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  • Electron microscopy  (84)
  • Immunocytochemistry  (44)
  • hypertension  (44)
  • Nitrate
  • Nitrogen fixation
  • Springer  (221)
  • 2025-2025
  • 1990-1994
  • 1980-1984  (221)
  • 1981  (116)
  • 1980  (105)
  • 1929
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Keywords
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  • 2025-2025
  • 1990-1994
  • 1980-1984  (221)
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  • 1
    Electronic Resource
    Electronic Resource
    Effects of cytochalasin B and dihydrocytochalasin B on calcium transport by intestinal absorptive cells (1981)
    Springer
    Calcified tissue international 33 (1981), S. 143-151 
    Details
    ISSN: 1432-0827
    Keywords: Calcium transport ; Cytochalasin B ; Dihydrocytochalasin B ; Colchicine ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In vivo calcium absorption was studied in normal and rachitic chicks. Cytochalasin B (CB) at a concentration of 25 µg/ml added to the medium inside the duodenal lumen inhibited calcium absorption (20 min) from 82.5±1.9% of calcium absorbed in the controls to 59.2±3% in normal and from 70.0±2.3% to 47.0±2.1% in rachitic chicks. In vitro studies by everted ileal sacs of young rabbits also showed an inhibition of active transport of calcium due to CB. Whereas in the controls the ratio of45Ca concentrations in serosal and mucosal media (60 min) was 7.2±0.32, the ratios were 5.24±0.52; 4.40±0.36; 3.40±0.42; 5.77±0.52; 1.38±0.08; and 1.06±0.02 in the presence of CB at concentrations of 5, 10 and 25 µg/ml; colchicine 10−4M, Na citrate 0.02M, and heat-devitalized conditions, respectively.45Ca concentration in the mucosal scrapings was also affected. It showed an increase from controls (15,101±404 cpm/mg) and correlated with CB concentration: 17,378±489, 19,015±1000, and 20,201±362 at 5, 10, and 25 µg/ml, respectively. Dihydrocytochalasin B also inhibited active calcium transport and caused an increase in45Ca concentration in the mucosal scrapings. Correlated electron microscopic studies showed certain changes in the brush border, especially in some actin microfilaments in the terminal web region. It seems that these morphological alterations may be related to transcytoplasmic movement of calcium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409427
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructure of the rat epiphyseal growth plate following chronic ethanol ingestion (1981)
    Springer
    Calcified tissue international 33 (1981), S. 381-384 
    Details
    ISSN: 1432-0827
    Keywords: Alcohol ; Electron microscopy ; Growth plate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have previously demonstrated that ethanol has a direct toxic effect on the rat skeleton characterized by decreased trabecular bone volume. In the present study, we examined the ultrastructure of the distal radial epiphyseal growth plates in these same animals. Eight weeks of ethanol administration to 12 male rats results in serum alcohol levels of 140 mg/dl but did not alter the width or light microscopic appearance of the radial growth plate. Quantitative electron microscopy failed to demonstrate morphologic evidence of toxicity in the skeletal cells. We conclude that although ethanol appears to have a direct effect on rat bone characterized by enhanced resorption, toxicity is not attended by ultrastructural changes in the skeletal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409460
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  • 3
    Electronic Resource
    Electronic Resource
    Biochemical and histological studies on various bone cell preparations (1981)
    Springer
    Calcified tissue international 33 (1981), S. 529-540 
    Details
    ISSN: 1432-0827
    Keywords: Bone cells ; Electron microscopy ; PTH ; PGE1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Four different cell populations—designated PF, OB, OC, and PC—were isolated from calvaria of 18-day-old chick embryos for analysis of the effects of hormones on bone tissue. The cell populations were studied with histological and biochemical methods. Apart from the well-known cell types present in calvaria, a new cell type was found in the noncalcified organic matrix between the osteoblastic layer and the calcified matrix. These cells were provisionally called osteocytic osteoblasts. They represent the “transition state” between osteoblasts and osteocytes. On the basis of histological studies with light microscopy (LM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), the PF population was considered to originate primarily from the periosteal fibroblasts, the OB population from the osteoblasts and osteocytic osteoblasts. The population of cells still present in calvaria after removal of periosteal fibroblasts and osteoblasts was called the OC population. This cell population was very much enriched with osteocytes. The fourth isolated population (PC) was a mixed population of fibroblasts, osteoblasts, and preosteoblasts. On exposure to parathyroid hormone (PTH), all four cell populations showed increased lactate production, but only the OB and OC populations displayed increased cAMP production. Prostaglandin E1 (PGE1) stimulated cAMP production in both OB and PF cells. From the results of this study it was concluded that PTH receptors are present on all of the cell types studied, but that occupancy of the receptor induces adenylate cyclase stimulation only in osteocytes and fully differentiated osteoblasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409485
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  • 4
    Electronic Resource
    Electronic Resource
    A scanning electron microscopic investigation of in vitro osteogenesis (1980)
    Springer
    Calcified tissue international 30 (1980), S. 43-50 
    Details
    ISSN: 1432-0827
    Keywords: Osteogenesis ; In vitro ; Electron microscopy ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chick limb mesenchymal cells differentiate into muscle, cartilage, fibrous, and bone tissue. Previous reports show that when stage 24 limb mesenchymal cells are cultured in vitro, chondrocytes, myocytes, fibrocytes, and osteoblasts can be identified on the basis of morphological and biochemical parameters. The study reported here demonstrates that phenotypic expression in culture seems to be dependent on the initial plating density, Scanning electron microscopic observations indicate that when stage 24 limb mesenchymal cells are initially seeded at high densities (5 × 106 cells per 35 mm culture dish), mounds of cells appear in culture. These mounds represent cartilage nodules composed of a fine fibrous matrix and chondrocytes, surrounded by a loose fibrous connective tissue matrix. Cultures initially plated at intermediate densities (2.0–2.5 × 106 cells/35 mm culture dish) produce a flattened layer of fibrocytes overlying a matrix of collagen fibers and calcium phosphate deposits as determined by electron-microprobe analysis; these observations are indicative of osteoblast expression. Cells seeded at this intermediate density appear larger and possess greater surface area than cells seeded at high density. It is suggested that conditions that permit such increased cell surface area coupled with a relative compaction due to cell crowding may provide conditions permissive for osteogenesis. Based on morphological criteria, it appears that chick limb mesenchymal cell osteogenesis in vitro is not associated with chondrogenesis but represents a separate route of phenotypic expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408605
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  • 5
    Electronic Resource
    Electronic Resource
    Fine structure of fetal rat calvarium; provisional identification of preosteoclasts (1980)
    Springer
    Calcified tissue international 31 (1980), S. 21-28 
    Details
    ISSN: 1432-0827
    Keywords: Rat ; Calvarium ; Electron microscopy ; Preosteoclasts ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive and relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407163
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of demineralization in an ethanolic solution of triethylammonium EDTA on solubility of bone matrix components and on ultrastructural preservation (1980)
    Springer
    Calcified tissue international 32 (1980), S. 175-179 
    Details
    ISSN: 1432-0827
    Keywords: Decalcification ; Electron microscopy ; Bone matrix ; Bone glycoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A solution of triethylammonium EDTA in 80% ethanol was evaluated as a demineralizing reagent for bone in comparison with aqueous solutions of EDTA. Biochemical analysis and acrylamide gel electrophoresis of extracts of finely powdered bovine bone showed that most of the macromolecular components of the organic matrix extractable in aqueous EDTA were retained when the triethylammonium EDTA reagent was used. Ultrastructural examination of chick tibias decalcified with the reagents showed a better preservation of cellular morphology, especially the membranous components, and more uniformly distributed ground substance, though slightly less in quantity, when the aqueous reagent was used. Use of the two reagents appears to be complementary, the alkylammonium reagent being more appropriate for use in studies of the organic matrix of bone, including immunohistochemical studies of bone glycoproteins. The aqueous reagent is more appropriate for use in studies of cellular ultrastructure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408537
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  • 7
    Electronic Resource
    Electronic Resource
    Crystal orientation in the shell of the domestic fowl: An electron diffraction study (1981)
    Springer
    Calcified tissue international 33 (1981), S. 119-124 
    Details
    ISSN: 1432-0827
    Keywords: Avian eggshell ; Microstructure ; Electron microscopy ; Electron diffraction ; Calcite growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The eggshell of the domestic fowl has been studied by transmission electron microscopy and diffraction. Thin sections of shell were prepared by chemical and ion-beam thinning techniques. Each calcite column of the palisade layer consisted of crystallites of diameter 20 to 30 µm with some tendency for crystallite alignment within a single column. Evidence indicates that there was no significant preferred orientation in the palisade layer as a whole. Only in the surface layer was any preferred orientation detected, and here {1014} planes tended to lie parallel to the surface. The results are compared with previously published data, and calcite nucleation and growth are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409423
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  • 8
    Electronic Resource
    Electronic Resource
    The roles of nitrate and ammonium in the regulation of the development of nitrate reductase in Chlamydomonas reinhardii (1980)
    Springer
    Planta 150 (1980), S. 13-18 
    Details
    ISSN: 1432-2048
    Keywords: Ammonium ; Chlamydomonas (mutant) ; Nitrate ; Nitrate reductase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The regulation of the development of nitrate reductase (NR) activity in Chlamydomonas reinhardii has been compared in a wild-type strain and in a mutant (nit-A) which possesses a modified nitrate reductase enzyme that is non-functional in vivo. The modified enzyme cannot use NAD(P)H as an electron donor for nitrate reduction and it differs from wild-type enzyme in that NR activity is not inactivated in vitro by incubation with NAD(P)H and small quantities of cyanide; it is inactivated when reduced benzyl viologen or flavin mononucleotide is present. After short periods of nitrogen starvation mutant organisms contain much higher levels of terminal-NR activity than do similarly treated wild-type ones. Despite the inability of the mutant to utilize nitrate, no nitrate or nitrite was found in nitrogen-starved cultures; it is therefore concluded that the appearance of NR activity is not a consequence of nitrification. After prolonged nitrogen starvation (22 h) the NR level in the mutant is low. It increases rapidly if nitrate is then added and this increase in activity does not occur in the presence of ammonium, tungstate or cycloheximide. Disappearance of preformed NR activity is stimulated by addition of tungstate and even more by addition of ammonium. The results are interpreted as evidence for a continuous turnover of NR in cells of the mutant with ammonium both stimulating NR breakdown and stopping NR synthesis. Nitrate protects the enzyme from breakdown. Reversible inactivation of NR activity is thought to play an insignificant rôle in the mutant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385608
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  • 9
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of reserve protein in the endoplasmic reticulum of developing bean (Phaseolus vulgaris) cotyledons (1980)
    Springer
    Planta 150 (1980), S. 419-425 
    Details
    ISSN: 1432-2048
    Keywords: Cotyledons ; Endoplasmic reticulum ; Ferritin labeling ; Immunocytochemistry ; Phaseolus ; Protein (reserve) ; Reserve protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ultrastructure of the storage parenchyma cells of the cotyledons of developing bean (Phaseolus vulgaris L.) seeds was examined in ultrathin frozen sections of specimens fixed in a mixture of glutaraldehyde, formaldehyde and acrolein, infused with 1 M sucrose, and sectioned at-80° C. Ultrastructural preservation was excellent and the various subcellular organelles could readily be identified in sections which had been stained with uranyl acetate and embedded in Carbowax and methylcellulose. The cells contained large protein bodies, numerous long endoplasmic reticulum cisternae, mitochondria, dictyosomes, and electron-dense vesicles ranging in size from 0.2 to 1.0 μm. Indirect immunolabelling using rabbit immunoglobulin G against purified phaseolin (7S reserve protein), and ferritin-conjugated goat immunoglobulin G against rabbit immunoglobulin G was used to localize phaseolin. With a concentration of 0.1 mg/ml of anti-phaseolin immunoglobin G, heavy labeling with ferritin particles was observed ober the protein bodies, the cisternae of the endoplasmic reticulum, and the vesicles. The same structures were lightly labeled when the concentration of the primary antigen was 0.02 mg/ml. Ferritin particles were also found over the Golgi bodies. The absence of ferritin particles from other organelles such as mitochondria and from areas of cytoplasm devoid of organelles indicated the specificity of the staining, especially at the lower concentration of anti-phaseolin immunoglobulin G.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00390179
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of combined nitrogen on anapleurotic carbon assimilation and bleeding sap composition in Phaseolus vulgaris L. (1980)
    Springer
    Planta 148 (1980), S. 338-345 
    Details
    ISSN: 1432-2048
    Keywords: Allantoin ; Amino acids ; Bleeding sap ; Nitrogen fixation ; Phaseolus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dwarf french beans, Phaseolus vulgaris L., were grown with or without inoculation with rhizobia (strain 3644), and with or without a combined nitrogen source (nitrate or ammonium ions). The distribution of radioactivity into products of dark 14CO2 assimilation was studied in roots or nodules from these plants. A detailed study was also made of the distribution and rates of excretion of nitrogen in xylem bleeding sap in 28 day old plants grown on the various sources of nitrogen. Whereas detached nodules accumulated radioactive glycine, serine and glutamate when incubated with 14CO2, bleeding sap from plants root fed 14CO2 contained low levels of radioactivity in these compounds but higher levels in allantoin. Chemical analysis showed allantoin to be the major compound transported in the xylem of nodulated plants, whether or not they were fed on combined nitrogen. In contrast uninoculated plants accumulated mainly amino acids in the bleeding sap, the amount and chemical composition of which depended on the combined nitrogen source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388121
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  • 11
    Electronic Resource
    Electronic Resource
    Effect of chemical inhibitors of photorespiration on nitrogenase activity in nodulated alfalfa plants (1980)
    Springer
    Planta 150 (1980), S. 299-302 
    Details
    ISSN: 1432-2048
    Keywords: Glyoxylate ; Isonicotinic acid hydracide ; Medicago ; Nitrogen fixation ; Photorespiration ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogen fixation (measured as acetylene reduction) by whole nodulated alfalfa plants was stimulated when the plants were treated with isonicotinic acid hydracide (INH) and glyoxylate, both inhibitors of the glycolate pathway of carbohydrate metabolism, at concentrations of 300 and 100 mM, respectively. Reducing energetic loses caused by photorespiration results in an increase in the symbiotic nitrogen fixation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384659
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  • 12
    Electronic Resource
    Electronic Resource
    On the cellular localization of phosphoenolpyruvate carboxylase in Sorghum leaves (1981)
    Springer
    Planta 151 (1981), S. 226-231 
    Details
    ISSN: 1432-2048
    Keywords: Immunocytochemistry ; (PEP carboxylase) ; PEP carboxylase ; Sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The localization of phosphoenol pyruvate carboxylase (EC 4.1.1.3.1.) in the leaf cells of Sorghum vulgare was investigated by using three techniques: the conventional aqueous and non aqueous methods gave conflicting results; the immunocytochemical techniques clearly showed that the enzyme is predominantly located in the cytoplasm of mesophyll cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395173
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  • 13
    Electronic Resource
    Electronic Resource
    15N2 Incorporation and metabolism in the lichen Peltigera aphthosa Willd (1981)
    Springer
    Planta 152 (1981), S. 544-552 
    Details
    ISSN: 1432-2048
    Keywords: Ammonium assimilation ; Lichens ; Nitrogen fixation ; Peltigera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Nostoc in the cephalodia of the lichen Peltigera aphthosa Willd. fixed 15N2 and the bulk of the nitrogen fixed was continuously transferred from it to its eukaryotic partners (a fungus and a green alga, Coccomyxa sp.). Kinetic studies carried out over the first 30 min, after exposure of isolated cephalodia to 15N2, showed that highest initial 15N2-labelling was into NH 4 + . After 12 min little further increase in the NH 4 + label occurred while that in the amide group of glutamine and in glutamate continued to increase. The 15N-labelling of the amino group of glutamine and of aspartate increased more slowly, followed by an increase in the labelling of alanine. When total incorporation of 15N-label was calculated, the overall pattern was found to be rather similar except that, throughout the experiment, the total 15N incorporated into glutamate was about six times greater than that into the amide group of glutamine. Pulse chase experiments, in which 14N2 was added to cephalodia previously exposed to 15N2, showed that the NH 4 + pool rapidly became depleted of 15N-label, followed by decreases in the labelling of glutamate, the amide group of glutamine and aspartate. The 15N-labelling of alanine, however, continued to increase for a period. When isolated cephalodia were treated with L-methionine-SR-sulphoximine, an inhibitor of glutamine synthetase (EC 6.3.1.2), and azaserine, an inhibitor of glutamate synthase (EC 2.6.1.53), there was no detectable labelling in glutamine although the 15N-labelling of glutamate increased unimpaired. On treating the cephalodia with amino-oxyacetate, an inhibitor of aminotransferase activity, the alanine pool decreased. Evidence was obtained that glutamine synthetase and glutamate synthase were located in the Nostoc, and that glutamate dehydrogenase (EC 1.4.1.4) and various amino-transferases were located in the cephalodial fungus. Possible implications of these findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380825
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  • 14
    Electronic Resource
    Electronic Resource
    Variable planar particle arrangements in the photosynthetic membrane of Rhodopseudomonas viridis (1981)
    Springer
    European biophysics journal 7 (1981), S. 209-212 
    Details
    ISSN: 1432-1017
    Keywords: Photosynthetic bacteria ; Electron microscopy ; Planar lattices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The thylakoids of Rhodopseudomonas viridis have been studied by freeze-fracturing whole cells. Depending on growth conditions and treatment before freezing, three different types of particle arrangements in the photosynthetic membrane are reported: a random arrangement, an isometric (quadratic) lattice arrangement with a lattice constant of 12.5 ± 0.8 nm, and a hexagonal lattice arrangement with a lattice constant of 12.5 ± 0.8 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539181
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  • 15
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of sotalol after chronic administration to patients with renal insufficiency (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 321-326 
    Details
    ISSN: 1432-1041
    Keywords: sotalol ; hypertension ; renal impairment ; chronic administration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Ten hypertensive patients with moderate to severe impairment of renal function were treated with sotalol for 5 to 10 weeks (average 6.4 weeks). Dosage was individually titrated (range 80 to 480 mg daily). The drug was given once daily in the morning. In eight patients blood pressure was satisfactorily controlled. Higher steady-state levels were observed than have been reported after similar doses in patients with normal renal function. The apparent first-order elimination rate constant and plasma clearance were significantly correlated with glomerular filtration rate. For an anuric patient, serum half-life was calculated to be 69 h. In relation to the raised plasma levels, side effects were uncommon. Since sotalol is excreted predominantly via the kidney, therapy in patients with impaired renal function should start with a low dose and any increase in dosage should be made carefully. As the anti-hypertensive effect does not appear to be correlated with the plasma level or with tolerance, adjustment of dose should be based on clinical response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561389
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  • 16
    Electronic Resource
    Electronic Resource
    Withdrawal of guanfacine after long-term treatment in essential hypertension (1981)
    Springer
    European journal of clinical pharmacology 19 (1981), S. 19-24 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; guanfacine ; central antihypertensives ; withdrawal ; catecholamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 1. Guanfacine (2–6 mg/day) a centrally acting antihypertensive drug, was effective in controlling blood pressure in 5 essential hypertensives and lowered plasma noradrenaline and urinary catecholamine excretion. 2. Withdrawal of guanfacine by blind substitution of identical placebo tablets under observation in hospital led to a gradual recovery of blood pressure over 2–4 days. 3. Salivary flow, which was reduced on guanfacine, returned to pretreatment levels by 2 days after withdrawal and significantly exceeded control for the next two days. 4. Urinary catecholamine excretion returned to pretreatment levels by 3 days but did not exceed control levels during the period of study. 5. Plasma noradrenaline returned gradually to pretreatment levels, and by day 4 significantly exceeded them. 6. No patient experienced symptoms suggesting catecholamine excess although four out of five reported a headache from the second day onwards. 7. Guanfacine, a centrally acting drug which pharmacologically resembles clonidine, has a slow offset of hypotensive effect over 2–3 days. Symptoms or biochemical evidence of catecholamine excess were not encountered within 48 h of withdrawal, possibly reflecting the longer duration of action and plasma half-life of guanfacine.
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    URL: http://dx.doi.org/10.1007/BF00558376
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  • 17
    Electronic Resource
    Electronic Resource
    Maximal exercise power after a single dose of metoprolol and of slow-release metoprolol (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 225-229 
    Details
    ISSN: 1432-1041
    Keywords: metoprolol ; hypertension ; slow-release preparations ; maximal exercise power ; fatigue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The treatment of hypertension with a single daily-dose of a beta-blocker gives rise to high peak-plasma concentrations 1.5 h after ingestion. After slow release-preparations of beta-blockers, the peak concentrations are half those produced by the conventional preparation at the same oral dose. A frequently occurring side-effect of beta-blocker therapy is fatigue. In this study the effect of a single dose of metoprolol 300 mg, 200 mg, 200 mg slow-release and a placebo on maximal exercise power was tested in 6 healthy subjects, 1.5 h and 24 h after ingestion. Maximal exercise power was significantly reduced 1.5 h after ingestion of metoprolol 300 mg and 200 mg. No change was found 1.5 h after 200 mg of a slow-release preparation. The possible reasons for reduced maximal exercise power are discussed. It is concluded that use of a beta-blocker for the treatment of hypertension in a single daily-dose regimen may be a reason to prefer a slow-release preparation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00563003
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  • 18
    Electronic Resource
    Electronic Resource
    Monoamine metabolites in cerebrospinal fluid during treatment of hypertension with prazosin (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 399-401 
    Details
    ISSN: 1432-1041
    Keywords: prazosin ; hypertension ; central monoaminergic neurons ; monoamine metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Six hypertensive patients were treated with prazosin up to a final dose of 3–4.5 mg/day. There was a significant reduction of blood pressure. The cerebrospinal fluid (CSF) concentrations of the major metabolites of noradrenaline, dopamine and serotonin were unchanged. This indicates that the antihypertensive effect is not mediated via central monoaminergic neurons as suggested by animal studies.
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    URL: http://dx.doi.org/10.1007/BF00636792
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  • 19
    Electronic Resource
    Electronic Resource
    Renin-angiotensin-aldosterone system (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 105-108 
    Details
    ISSN: 1432-1041
    Keywords: renin ; angiotensin ; aldosterone ; hypertension ; hypoaldosteronism ; pseudohypoaldosteronism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary There is increased activity of the renin, angiotensin, aldosterone (RAA) system in infancy and childhood. An inverse relationship between plasma renin, aldosterone and age has been demonstrated. In childhood hypertension due to renovascular disease or pyelonephritic scarring peripheral plasma renin is increased. Renal vein renin measurements in children with renal hypertension have proved valuable in predicting surgical curability of the underlying lesion. The upper limit of normal for the renal venous renin ratio in normotensive children without renal disease is 1.5. Pharmacological blockade of the RAA system has a place in diagnosis and treatment of hypertensive children. The plasma renin aldosterone profile is diagnostically useful in the investigation of salt-wasting disease and can easily distinguish between aldosterone biosynthetic defects and pseudohypoaldosteronism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561486
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  • 20
    Electronic Resource
    Electronic Resource
    Comparison of the effects of propranolol and labetalol on renal haemodynamics at rest and during exercise in essential hypertension (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 135-139 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; labetalol ; propranolol ; renal haemodynamics ; glomerular filtration rate ; blood pressure ; exercise ; renal blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of exercise on renal haemodynamics was examined in young patients with mild essential hypertension. Four groups of subjects were studied: 13 normotensive, healthy control subjects, and 15 untreated, 11 propranolol-treated, and 6 labetalol-treated patients. Renal plasma flow (RPF) and glomerular filtration rate (GFR) were measured during four consecutive periods, a pre-exercise control period, two exercise periods with loads of 450 kpm/min and 600 kpm/min, respectively, and a post-exercise control period. In the untreated patients RPF and GFR were lower during exercise than in the normotensive control subjects, whereas no significant differences were found at rest. In the propranolol-treated patients the reduction in RPF and GFR during exercise was more pronounced than in the untreated hypertensives. In the labetalol-treated patients however, RPF and GFR were reduced only to the same degree as in the untreated hypertensives. The reduced renal blood flow in propranolol-treated patients may be attributed to a compensatory increase in sympathetic activity caused by an impaired cardiac response to exercise. The lack of reduction in renal blood flow during labetalol therapy could partly be related to alpha-adrenergic blockade in the renal vascular bed induced by labetalol, and partly to the smaller reduction in cardiac output during labetalol than during propranolol therapy.
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    URL: http://dx.doi.org/10.1007/BF00561580
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    Double-blind controlled trial of molsidomine in hypertension (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 231-235 
    Details
    ISSN: 1432-1041
    Keywords: molsidomine ; hypertension ; hypotension ; angina pectoris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Molsidomine (M), a new long-lasting antianginal compound, was studied in 38 hypertensive patients to assess its antihypertensive properties. Six patients were selected for an acute, single dose comparative trial with placebo over 8 h after treatment. The remaining 32 patients were used in a 1 month trial to study the effect on BP of more prolonged treatment. Systolic, diastolic and mean BP were significantly reduced after a single dose of M 4 mg, and the effect lasted for about 8 h. M also inhibited the hypertensive response to isometric exercise in handgrip tests performed 1 and 8 h after M ingestion. A dose-related decrease in systolic and diastolic BP in the one month trial was also observed. In addition to its antianginal properties, M appears to possess an interesting effect on BP in mildly to moderately hypertensive patients. A fall in BP is also a valuable effect in coronary patients with augmented metabolic demands of the heart.
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    URL: http://dx.doi.org/10.1007/BF00563004
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  • 22
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    Relationship between the antihypertensive effect and steady-state plasma concentration of nifedipine given alone or in combination with a beta-adrenoceptor blocking agent (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 287-293 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; nifedipine ; beta-adrenoceptor blockade ; hypotensive action ; adverse effects ; combination therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive effect of nifedipine (10–20 mg t.i.d.) given alone, or in combination with a beta-adrenoceptor blocking drug, was related to the observed plasma concentration during one dosage interval at steady-state (Pl-Nifss). The study was carried out as a within-patient comparison of treatment with nifedipine or placebo for 4 weeks. A highly significant reduction in blood pressure was obtained during monotherapy, as well as during combined treatment. The blood pressure reduction when nifedipine was added to beta-adrenoceptor blockade was of the same magnitude as that observed on nifedipine monotherapy. A considerable variation in Pl-Nifss was noted (range: 2–70 ng/ml). No significant correlation was found between the percentage reduction in blood pressure and Pl-Nifss in either of the two groups. There was a close relationship between Pl-Nifss and the concentration found 4 h after the morning dose. Side-effects were common during nifedipine monotherapy and were the reason for discontinuation of treatment in 4 of 18 patients. In contrast, none of the 9 patients on combined treatment dropped-out. In neither of the treatment groups was there any evidence for sodium retention and volume expansion during the first 4 weeks expressed as weight gain or signs of cardiac insufficiency. However, in 13 patients who continued on long-term treatment for 3–14 months, a definite need for concomitant diuretic therapy was found. The results indicate that nifedipine is effective in lowering blood pressure in patients with mild to moderate essential hypertension, either when given alone or in addition to beta-adrenoceptor blockade. It appears best tolerated as combination therapy. Long-term treatment requires addition of a diuretic. Pl-Nifss did not seem to be a major determinant of the magnitude of the hypotensive response.
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    URL: http://dx.doi.org/10.1007/BF00561384
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  • 23
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    Antihypertensive and renal effects of orally administered verapamil (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 375-382 
    Details
    ISSN: 1432-1041
    Keywords: calcium antagonist ; verapamil ; hypertension ; vasodilators ; plasma renin activity ; mode of action ; sodium balance ; fluid balance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In 12 in-patients with moderate uncomplicated hypertension, maintained on constant sodium intake for 15 days, single-blind oral administration of verapamil 80–160 mg t. i. d. for 10 days had a significant antihypertensive effect: in the supine position systolic blood pressure decreased from 177±5 to 150±3 mmHg, and diastolic pressure from 111±3 to 96±2 mmHg; standing values were similarly lowered from 171±7 to 143±4 mmHg, systolic, and from 118±4 to 97±2 mmHg, diastolic. The heart rate did not show any significant change (from 79±3 to 77±2 beats/min, supine, and from 92±3 to 87±3 beats/min, upright). The antihypertensive effect was uniform throughout the day, being similar 2, 3, 6 and 8 h after administration of a dose. Dynamic exercise (75–100 watts on a cycle-ergometer) caused identical increases in arterial pressure and heart rate on the last day of placebo and again on the last day with verapamil, but the peak levels of systolic pressure reached during exercise were lower after verapamil than with placebo, because of the lower blood pressure before exercise. Reduction of arterial pressure by verapamil was not accompanied by increased plasma renin activity, or by renal retention of sodium and water: there was a small increase in sodium excretion, at least during the first days of verapamil administration (from 107±15 to 113±15 mEq Na+/day), and a slight significant reduction in body weight (from 74.2±3.7 to 73.5±3.7 kg). It is concluded that oral administration of verapamil significantly lowers blood pressure without simultaneously inducing cardiac stimulation, renin secretion or salt and water retention.
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    URL: http://dx.doi.org/10.1007/BF00636788
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  • 24
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    Double-blind trial comparing guanfacine and methyldopa in patients with essential hypertension (1981)
    Springer
    European journal of clinical pharmacology 19 (1981), S. 309-315 
    Details
    ISSN: 1432-1041
    Keywords: guanfacine ; methyldopa ; hypertension ; rebound hypertension ; withdrawal symptoms ; plasma noradrenaline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nine patients with essential hypertension completed a clinical trial designed to study the effects and side effects of administration and withdrawal of guanfacine (2 mg tds) and methyldopa (250 mg tds) on blood pressure, heart rate, and plasma noradrenaline. The study was of randomised doubleblind crossover design with two active therapy phases of eight weeks each, preceded by an initial 4 week placebo phase, separated by an intermediate 2 week placebo phase, and followed by a final 2 week placebo phase. Patients took bendrofluazide 5 mgs daily throughout the entire trial, during both active and placebo periods. Each patient was admitted to hospital at the end of the 8 week active treatment phases, so that the effects of drug withdrawal on blood pressure, heart rate, plasma noradrenaline and side reactions, could be closely observed and monitored. The main conclusions from analysis of the results were that: 1. The hypotensive efficacy of guanfacine and methyldopa was very similar in the doses used, each of the two drugs lowering the supine mean arterial pressure by about 15 mm Hg and the supine diastolic pressure by about 10 mm Hg. 2. The frequency of side effects was greater with guanfacine than with methyldopa. 3. There was no signficant early rebound phenomenon after withdrawal of either methyldopa or guanfacine. 4. There was tendency for the blood pressure to rise slowly and marginally above initial placebo values, 2 weeks after cessation of guanfacine treatment though this was not significant. It was however, accompanied by a significant increase in plasma noradrenaline at 2 weeks. This was not seen 2 weeks after cessation of methyldopa. There was no single incidence of worrying rebound hypertension or withdrawal symptoms either early or late in any patient following cessation of methyldopa or guanfacine.
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    URL: http://dx.doi.org/10.1007/BF00544579
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    Haemodynamic profile of captopril treatment in various forms of hypertension (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 163-168 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; captopril ; cardiac output ; extracellular fluid volume ; renin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of captopril 450 mg/day for 4 weeks on blood pressure, heart rate, cardiac output and extracellular fluid volume were compared in severe, often drug-resistant hypertension (n=23), mild to moderate hypertension associated with renal artery stenosis (n=10) and mild to moderate essential hypertension (n=20). Plasma renin in the three groups was 52±19, 58±17 and 20±4 µU/ml (mean ± SEM), respectively. Blood pressure fell by 18±4%, 21±2% and 18±1%. The pressure drop was mainly due to a fall in peripheral vascular resistance. Addition of the diuretic hydrochlorothiazide (25–100 mg/day) caused a further fall in resistance. Despite the vasodilator effect of captopril, reflex cardiostimulation and reactive fluid retention were not observed. In severe hypertension, captopril alone was more effective in lowering blood pressure than combined diuretic-betablocker-vasodilator therapy. Moreover, cardiac output in these patients was higher and resistance was lower after captopril than during combined treatment. Thus, captopril was capable of normalising the abnormal haemodynamic state in patients with essential hypertension, and in hypertension associated with renal artery stenosis. Despite marked differences in pre-treatment plasma renin, the effects of captopril on systemic haemodynamics were similar in all the patients.
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    URL: http://dx.doi.org/10.1007/BF00544593
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    Acute effects of a new vasodilator, Ro 12-4713, on blood pressure, plasma renin activity, aldosterone and catecholamine levels, and renal function in hypertensive and normal subjects (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 169-177 
    Details
    ISSN: 1432-1041
    Keywords: vasodilator ; hypertension ; haemodynamic effects ; renal plasma flow ; renal tubular function ; plasma renin activity ; aldosterone ; Ro 12-4713
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Selected cardiovascular and endocrine effects of the new oral vasodilator Ro 12-4713 have been evaluated in an acute single dose study. In five patients with essential hypertension, Ro 12-4713 caused a dose-dependent decrease in supine and upright blood pressure and an increase in heart rate. Initial effects occurred one to 2 h after drug ingestion and maximal effects were noted after five hours and persisted for at least 8 h. Blood pressure was normalized, and the antihypertensive and chronotropic effects persisted for 24 h after a dose of about 300 mg/1.73 m2. Plasma and urinary norepinephrine and plasma renin levels tended to be raised, whereas plasma and urinary epinephrine and plasma aldosterone did not change. Changes in supine heart rate were inversely correlated with changes in mean blood pressure (r=−0.60; P〈0.02), and positively with those in plasma norepinephrine (r=0.55; P〈0.05) and renin (r=0.62, P〈0.01); changes in supine plasma renin level were also inversely correlated with those in mean blood pressure (r=−0.65; P〈0.01), and positively with those in plasma norepinephrine (r=0.58; P〈0.05). 24 h-urinary sodium excretion was significantly (P〈0.001) decreased; it was positively correlated with mean blood pressure (r=0.51; P〈0.05) and inversely with supine plasma renin activity (r=−0.63; P〈0.01). In six normal subjects and six patients with essential hypertension, effective renal plasma flow and the renal clearance of sodium, potassium, calcium and uric acid were not significantly altered five hours after a dose of Ro 12-4713 of about 250 mg/1.73 m2; glomerular filtration rate tended to be slightly decreased, and filtration fraction was significantly (P〈0.05) reduced in the hypertensive patients. At the same time blood pressure was decreased and plasma norepinephrine (P〈0.01) and renin (ns) were slightly increased in both groups. Ro 12-4713 in a single oral dose of about 300 mg appeared to be a potent, long acting, hypotensive vasodilator.
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    URL: http://dx.doi.org/10.1007/BF00544594
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    Time-course of the anti-hypertensive action of atenolol: Comparison of response to first dose and to maintained oral administration (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 365-374 
    Details
    ISSN: 1432-1041
    Keywords: atenolol ; hypertension ; plasma renin activity ; pharmacokinetics ; pharmacodynamic effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To show whether repeated administration of atenolol for several days would influence its pharmacokinetic parameters and the extent and duration of the pharmacologic responses, the plasma level of atenolol and changes in heart rate, blood pressure and plasma renin activity were measured in 12 hypertensive patients at various times of day (9 a. m., 12 noon, 3 p. m. and 7 p. m.) after oral administration of the first dose of atenolol 100 mg, again during the 7th and 14th days of continued once-daily administration of the same dose, and finally during the three days following withdrawal of the drug. The peak plasma concentration of atenolol (about 600 ng/ml) was found 3 h after administration of the first dose, and measurable amounts (50–70 ng/ml) were found after 24 h. None of the pharmacokinetic characteristics were changed by administration of a single daily dose for two weeks. After withdrawal of the drug, detectable amounts of atenolol were found in plasma for at least 48 h. The first dose of atenolol caused prompt (3 h) and prolonged (up to 24 h) lowering of supine and standing systolic and diastolic blood pressures, slowing of supine and standing heart rate, reduction of the blood pressure and heart rate responses to dynamic exercise, and a decrease in plasma renin activity. The extent and time-course of all these responses were not influenced by repeated once-daily administration of the 100 mg dose for two weeks. Most of the effects continued during the withdrawal days, the lowering of blood pressure being somewhat more prolonged than the slowing of heart rate. It is concluded that a once-daily dose of atenolol 100 mg decreases blood pressure and heart rate throughout the following 24 h, without excessive daily fluctuation in its effects, and without signs of tolerance or accumulation.
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    URL: http://dx.doi.org/10.1007/BF00636787
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    Once-daily dosing of timolol in hypertension: A controlled study (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 239-241 
    Details
    ISSN: 1432-1041
    Keywords: timolol ; hypertension ; dose ranging ; double-blind trial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nine previously untreated patients with mild-moderate hypertension were included in a dose-ranging double-blind trial to determine the effectiveness of daily versus thrice daily timolol administration. In 8 patients control of blood pressure was equally effective though with significantly lower heart rate achieved in the once daily group. One patient was not satisfactorily controlled on the daily regimen demonstrating that many but not all hypertensives can be controlled with daily administration of timolol.
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    URL: http://dx.doi.org/10.1007/BF00625796
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    Relationship of propranolol pharmacokinetics to antihypertensive effect and beta-adrenergic blockade in the treatment of hypertension (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 391-394 
    Details
    ISSN: 1432-1041
    Keywords: propranolol ; hypertension ; beta-adrenergic blockade ; exercise heart rate ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of propranolol in 16 hypertensive patients was compared after the first oral dose of 80 mg and during chronic treatment with 80 mg bd. The degree of beta-adrenergic blockade was estimated by the reduction in maximal exercise heart rate. No significant change in plasma half-life occurred and there was no correlation between the mean steady-state propranolol concentration and beta-adrenergic blockade or antihypertensive effect. A linear relationship was observed between the decrease in blood pressure and the reduction in heart rate during maximal exercise. Therefore, the antihypertensive effect of propranolol can be explained by its peripheral beta-adrenergic blocking properties.
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    URL: http://dx.doi.org/10.1007/BF00636790
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    Long-term clonidine effects on autonomic function in essential hypertensive man (1981)
    Springer
    European journal of clinical pharmacology 19 (1981), S. 25-32 
    Details
    ISSN: 1432-1041
    Keywords: clonidine ; hypertension ; baroreceptor reflex ; mode of action ; sympathetic activity ; urinary catecholamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Acute studies of clonidine suggest that it lowers blood pressure by central enhancement of baroreflex sensitivity coupled with diminished evidence of sympathetic outflow, but longterm clonidine data have not been conclusive. We examined effects of one month of low dose clonidine (0.4 ± 0.15 mg/day) alone in 13 essential hypertensive men, assessing several biochemical indices of sympathetic function, as well as physiologic parameters, including baroreflex sensitivity, the cold pressor test, and the hypotensive response to alpha adrenergic blockade. Clonidine diminished mean arterial pressure (from 104±5 to 84±3 mmHg;p〈0.01), without associated changes in several biochemical parameters of sympathetic outflow (urinary excretion of catecholamines, metanephrines, and vanillylmandelic acid; allp〉0.1). Circulatory baroreflex function was not enhanced by clonidine, during either the amylnitrite test or the phenylephrine test, before or after parasympathetic blockade with atropine. The cold pressor test, an index of efferent sympathetic pressor function, was also unaltered. The enhanced mean arterial pressure response to phentolamine during clonidine therapy (from a fall of 14.8±4.3 to 39.4±5.2 mmHg,p〈0.01), suggested an increase in alpha adrenergic vascular tone, perhaps mediated by clonidine's alpha agonist properties in vascular smooth muscle. The antihypertensive mechanism of longterm low dose clonidine cannot reliably be ascribed either to baroreflex enhancement or to suppression of sympathetic outflow.
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    URL: http://dx.doi.org/10.1007/BF00558378
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    A clinical and pharmacokinetic evaluation of tolmesoxide in hypertensive patients (1981)
    Springer
    European journal of clinical pharmacology 19 (1981), S. 113-118 
    Details
    ISSN: 1432-1041
    Keywords: tolmesoxide ; vasodilators ; hypertension ; side-effects ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics, hypotensive effect and tolerability of a new vasodilator, tolmesoxide (T), have been studied in 6 uncontrolled hypertensive patients receiving atenolol and a diuretic. After a 50 mg oral dose mean (± SD) peak plasma concentration of T was 1.13±0.29 µg/ml−1 and occurred 0.79±0.40 h after the dose; mean peak plasma concentration of its sulphone metabolite (M) was 0.37±0.09 µg/ml−1 at 1.92±1.32 h after the dose. Following peak plasma concentrations there was a monoexponential decline in T and M concentrations with half-lives of 2.78±0.77 h and 10.78±7.85 h respectively. There was a linear increase in plasma concentration of T and M during incremental dosing with 50–200 mg t. i. d. During in-patient administration of 600–900 mg T daily (n=6) there was no significant change in blood pressure, pulse rate or body weight. Out-patient administration of 900 mg T daily (n=4) was associated with a significant fall in mean systolic but not diastolic bp (lying −15/+1 mm Hg. standing −25/−8 mm Hg). A further fall was observed in 2 subjects receiving 1200 mg and 1500 mg daily. Supine pulse rate increased (mean ± SD) significantly from 55±5/min to 66±8/min following 900–1500 mg T in 4 out-patients. Severe nausea and other gastro-intestinal side-effects in all subjects receiving 600–900 mg daily eventually necessitated drug withdrawal. In its present from T is not recommended for the treatment of hypertension.
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    URL: http://dx.doi.org/10.1007/BF00568397
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    A controlled study of the antihypertensive effect of carteolol, a newβ-adrenergic receptor blocking drug, in combination with hydrochlorthiazide and amiloride (1981)
    Springer
    European journal of clinical pharmacology 19 (1981), S. 239-244 
    Details
    ISSN: 1432-1041
    Keywords: carteolol ; hydrochlorthiazide ; amiloride ; hypertension ; double-blind clinical trial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive effect of carteolol, a new β-blocking agent, added to basal diuretic treatment (hydrochlorthiazide 50 mg and amiloride 5 mg) has been assessed in a controlled trial in 17 patients with mild-to-moderate hypertension. The trial was divided into 4 stages: 1) run-in period with no antihypertensive treatment, 2) diuretic period (the diuretic being continued as basal treatment during the two following periods), 3) carteolol titration period, and 4) double-blind cross-over period comparing carteolol with placebo, which lasted 2 times 4 weeks. Although the diuretic effectively reduced the blood pressure, 17 of the 20 patients originally studied still had an elevated diastolic blood pressure (≧ 95 mmHg) after the diuretic period, thus fulfilling the inclusion criteria for the study. During the titration period carteolol 5 to 20 mg b. i. d. significantly reduced the elevated blood pressure. The blood pressure was reduced to normal in all 17 patients, although in two patients this occurred only during the double-blind period. During the double-blind period, the dose of carteolol was used which had given a satisfactory response during the titration period. The blood pressure in the 14 patients who completed the trial remained low both with carteolol and placebo during the double-blind stage, and was only slightly lower with carteolol than with placebo. This is probably due to a “carry-over” effect. Three patients discontinued the trial due to side effects (1 urticaria, 1 insomnia and 1 nausea) while on carteolol. There was no other difference between carteolol and placebo in the number or severity of side effects.
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    URL: http://dx.doi.org/10.1007/BF00562799
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    Chronic treatment with the new potent vasodilator Ro 12-4713 in moderate to severe hypertension: Effects on blood pressure, endocrine function, sodium and plasma volume (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 79-84 
    Details
    ISSN: 1432-1041
    Keywords: vasodilator ; hypertension ; antihypertensive treatment ; catecholamines ; renin ; aldosterone ; blood volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive efficacy and endocrine profile of the new antihypertensive agent, Ro 12-4713, were evaluated in 23 patients (17 men and 6 women) with moderate to severe arterial hypertension. Following addition of Ro 12-4713 to pre-existing therapy with diuretics and beta-blockers or sympatholytics, blood pressure in most of the patients was normalized within one month by a daily dose of 60 to 120 mg. Heart rate was only slightly increased. Orthostatic hypotension was not observed. Weight gain or oedema formation occurred in 14 patients within the first four weeks, but could be controlled satisfactorily by intensified diuretic therapy. Increased hair growth occurred in most of the patients. After a mean duration of treatment of 2.8 months, plasma volume and plasma and urine sodium were unaltered, and plasma potassium was slightly decreased. Plasma renin activity was doubled, whereas plasma aldosterone concentrations were unaltered. Plasma norepinephrine levels were high before and increased only slightly during chronic Ro 12-4713 treatment, whereas urinary norepinephrine excretion was unchanged. Plasma and urinary epinephrine were unaltered by Ro 12-4713. Ro 12-4713 appears to be a potent vasodilator for the combination treatment of hypertension in men.
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    URL: http://dx.doi.org/10.1007/BF00607141
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    Serum lipoprotein changes during atenolol treatment of essential hypertension (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 335-338 
    Details
    ISSN: 1432-1041
    Keywords: atenolol ; atherosclerosis ; hypertension ; serum lipoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Serum lipoproteins were determined in 15 patients before and during antihypertensive treatment with atenolol 0.1–0.2 g/day for a mean of 8 months. The mean blood pressure fell from 171/103 to 154/93 mm Hg (p〈0.05). Significant lipoprotein changes were an increase in very low density triglycerides (VLDL-TG) from 1.21±0.95 (SD) to 1.62±1.24 mmol/l (p〈0.01) and in low density (LDL) TG from 0.46±0.12 to 0.51±0.12 mmol/l (p〈0.05). Together, these TG increases resulted in development of hypertriglyceridaemia in 7/15 patients during atenolol treatment. No effect on whole serum cholesterol or on the high density lipoprotein cholesterol concentrations were found. Thus, some patients on long term treatment with atenolol seem to receive the benefit of normotension at the cost of hypertriglyceridaemia. This may have practical implications, since hypertriglyceridaemia constitutes an important risk factor for atherosclerosis.
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    URL: http://dx.doi.org/10.1007/BF00615401
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    Prolactin secretion during reserpine and syrosingopine treatment (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 347-349 
    Details
    ISSN: 1432-1041
    Keywords: reserpine ; syrosingopine ; prolactin secretion ; hypertension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In 20 mild hypertensive women, reserpine induced a significant increase in mean plasma PRL, both under basal conditions (from 6.6±0.9 to 17.9±2.9 ng/ml), and on repeated determinations during the day. In contrast to reserpine, the administration of syrosingopine, a synthetic compound derived from reserpine, to the same subjects was not followed by a significant change in prolactin level. Beyond their pharmacological interest, these results are of clinical importance when considering that rauwolfia alkaloids are used for long term treatment, and that an increase in PRL levels is important in pathology, both in relation to the function of the hypophyseogonadal axis and in view of its possible facilitation of the growth and development of mammary cancer.
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    URL: http://dx.doi.org/10.1007/BF00615404
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    Reserpine, hydrochlorothiazide and pituitary-gonadal hormones in hypertensive patients (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 329-332 
    Details
    ISSN: 1432-1041
    Keywords: reserpine ; hydrochlorothiazide ; pituitary hormones ; gonadal hormones ; hypertension ; serum concentration ; antihypertensive therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Sex histories and serum samples were obtained from 27 hypertensive men before and after 3 months of therapy with either 100 mg of hydrochlorothiazide or 0.25 mg of reserpine daily. Sera were analyzed for testosterone, dihydrotestosterone, estradiol, luteinizing hormone and prolactin. Both drugs effectively lowered blood pressure. The incidence of impaired sexual performance was low and insignificantly different in the two treatment groups. There were no significant changes in serum hormone concentrations as a result of drug therapy.
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    URL: http://dx.doi.org/10.1007/BF00558444
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    Single daily dose penbutolol in the treatment of hypertension: A double blind crossover comparison with propranolol (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 409-413 
    Details
    ISSN: 1432-1041
    Keywords: penbutolol ; hypertension ; propranolol ; double-blind crossover comparison ; blood pressure ; heart rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Penbutolol is a potent long-acting non-cardioselective beta-adrenergic blocker with partial agonist activity. A double-blind cross-over comparison of penbutolol given in a single daily dose and propranolol given twice daily in the treatment of ambulant patients with moderate hypertension is described. Fourteen patients completed the study and were treated with each drug for 12 weeks. Penbutolol in daily doses of 20–120 mg and propranolol in daily doses of 80–400 mg produced similar significant reductions in both supine and erect blood pressure. Penbutolol did not reduce heart rate to the same extent as propranolol, in equivalent doses. Penbutolol appears to produce adequate control of moderate hypertension when administered once a day, and this effect appears to be equivalent to divided doses of propranolol. No serious adverse effects were reported, although one patient receiving penbutolol experienced severe eye pains at a dose of 40 mg which resolved on crossing over to treatment with propranolol.
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    Influence of propranolol and pindolol on the haemodynamic effects of papaverine, isoprenaline and noradrenaline in hypertensive patients (1980)
    Springer
    European journal of clinical pharmacology 18 (1980), S. 141-146 
    Details
    ISSN: 1432-1041
    Keywords: papaverine ; propranolol ; pindolol ; hypertension ; isoprenaline ; haemodynamic effects ; blood pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of two β-adrenoceptor antagonists, propranolol and pindolol, on the haemodynamic effects of papaverine, isoprenaline and noradrenaline was investigated in 9 male patients with first degree essential hypertension. Propranolol and pindolol were given according to a doubleblind, crossover scheme. Heart rate and blood pressure were measured before and after each treatment. Propranolol 670 µg/kg i. v. reduced the supine and standing systolic blood pressures by 2.3% and 1.6%, respectively. Similarly, the intravenous administration of pindolol 35 µg/kg reduced supine and standing systolic blood pressure by 5.5% and 8.3% respectively (clinically insignificant). Neither drug affected diastolic blood pressure. Following propranolol, there were moderate reductions in supine and standing heart rates, respectively by 24% and 20% (p〈0.001). Similarly, but to a lesser extent, pindolol reduced supine and standing heart rate by 12% and 17% (p〈0.001). The effects of papaverine, which, at 1.5 mg/kg i. v. reduced systolic blood pressure by 5–10% and increased heart rate by 8–15%, were not significantly influenced by the β-blockers. The blood pressure and heart rate responses to isoprenaline, on the other hand, were attenuated or inhibited by both β-blockers. While the β-blockers inhibited the β-adrenoceptor component of noradrenaline, the pressor component of noradrenaline, which is mediated through the α-adrenoceptors, was not influenced by propranolol, but was inhibited after pindolol. It is concluded that pindolol differs qualitatively from propranolol in that it inhibited both the α-and β-adrenoceptor effects of noradrenaline.
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    URL: http://dx.doi.org/10.1007/BF00561581
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  • 39
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    Fixed combination of sotalol and hydrochlorothiazide in the treatment of uncomplicated hypertension (1981)
    Springer
    European journal of clinical pharmacology 19 (1981), S. 395-401 
    Details
    ISSN: 1432-1041
    Keywords: sotalol ; hydrochlorothiazide ; hypertension ; combination fixed ratio ; serum potassium ; long term treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The combination of sotalol and hydrochlorothiazide in a fixed ratio of 6.4:1 was evaluated in thirty patients with uncomplicated hypertension. In the first part of the study, once daily administration of an optimal dose of the combination was significantly more effective than either hydrochlorothiazide or sotalol alone in lowering both the supine and standing systolic and diastolic blood pressure. Blood pressure was still controlled 24 h after the previous dose. Serum potassium fell by 0.37 mEq/l from the mean pretreatment value after treatment with the combination, but it still remained within the normal range. In the second part of the study the long term effect of the combination on blood pressure, heart rate and biochemical parameters was studied in twenty patients. Supine and standing blood pressure fell by 28.7/15.3 mmHg and 29.5/17.6 mmHg, respectively (p〈0.001). Serum potassium was 3.98±0.07 mEq/l after twelve months of therapy; potassium supplements were not administered. Like serum potassium, the other biochemical parameters remained within the normal range. The combination was well tolerated on long term use, and only one patient withdrew from the study.
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  • 40
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    Time course of blood pressure, pulse rate, plasma renin and metoprolol during treatment of hypertensive patients (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 321-328 
    Details
    ISSN: 1432-1041
    Keywords: metoprolol ; hypertension ; pharmacokinetics ; plasma renin ; blood pressure effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Eleven patients were treated for essential hypertension with metoprolol (Selokén®) for more than three months. The time course of changes in blood pressure, pulse rate and plasma renin activity was studied during treatment with an oral maintenance dose of 100 mg twice daily. Significant decreases in pulse rate, diastolic blood pressure and plasma renin activity were observed even after the first dose. The plasma concentration of metoprolol reached equilibrium after the second dose. After the third dose there was no further significant change in blood pressure. There was a significant correlation (p〈0.001) between the initial (after three doses) and final (after 〉90days) effect of metoprolol on blood pressure (r=0.86 and 0.91 for systolic and diastolic blood pressure change, respectively).
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  • 41
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    Role of various vasodepressor systems in the acute hypotensive effect of captopril in man (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 1-8 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; captopril ; angiotensin ; renin ; aldosterone ; catecholamines ; prostaglandins ; kininase II ; hypotensive action
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The acute hypotensive effect of captopril 25 mg was investigated in 26 hypertensive patients (11 with essential and 15 with renal arterial disease). Intra-arterial blood pressure was recorded continuously and arterial blood was sampled for renin, angiotensin I and II, aldosterone, kininase II, catecholamines and prostaglandins. Captopril led to an increase in plasma renin activity, active and total plasma renin concentration and angiotensin I, a decrease in plasma kininase II activity, angiotensin II, aldosterone, prostaglandins E2 and F2* and no change in plasma (nor)adrenaline, dopamine and inactive renin concentration. The hypotensive effect of captopril was related to the changes in plasma angiotensin II level and inversely to the change in prostaglandin E2; the correlation coefficients were low, respectively 0.61 and −0.44. It is likely that the acute hypotensive effect of captopril to some extent is related to changes in plasma angiotensin II and in prostaglandins E2 and F2*. There is no evidence for a role of the adrenergic systems in the hypotensive response.
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  • 42
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    Antihypertensive effect of E-643, a new alpha-adrenergic blocking agent (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 399-405 
    Details
    ISSN: 1432-1041
    Keywords: alpha-adrenergic blocker ; hypertension ; blood pressure ; pulse rate ; noradrenaline ; plasma renin activity ; plasma aldosterone ; dopamine-beta-hydroxylase ; E-643
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To determine whether E-643, a new α-blocking agent, would reduce the blood pressure, regardless of the posture, a 1 mg dose was given 3 times daily for 7 consecutive days, to 8 male and 7 female inpatients, aged 37–73 years, with essential hypertension. Blood pressure and pulse rate were measured daily in the supine, sitting and standing positions. Before and after the treatment with E-643, plasma levels of noradrenaline, adrenaline, dopamine-β-hydroxylase, renin and aldosterone were determined, samples being obtained with the subjects recumbent and after standing upright for 60 min. A significant reduction in the systolic and diastolic blood pressures was evident in the supine (172±31/100±12 → 151±28/89±14 mmHg), sitting (158±22/101±11 → 138±28/89±15 mmHg) and standing (153±32/103±21 → 129±31/89±20 mmHg) positions. The reduction in blood pressure remained unchanged throughout the period of administration of E-643. Pulse rate was not affected when the subjects were supine (67±10 → 69±10 beats/min), but was increased in the sitting (68±10 → 73±9 beats/min) and standing (73±10 → 81±11 beats/min) positions. The increased pulse rate tended to decline during continued administration of E-643. Treatment with E-643 produced no significant change in plasma levels of adrenaline, noradrenaline, dopamine-β-hydroxylase, renin and aldosterone. The antihypertensive effect of treatment was more prominent in the patients with higher levels of plasma catecholamines and dopamine-β-hydroxylase, and was less prominent in those with higher plasma renin and aldosterone. Two patients had temporary bouts of dizziness and visual disturbances, but there were no subjective complaints during treatment.
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  • 43
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    Chlorthalidone in mild hypertension — Dose response relationship (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 407-411 
    Details
    ISSN: 1432-1041
    Keywords: chlorthalidone ; hypertension ; dose response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The dose response curve for 25, 50, 75 and 100 mg doses of chlorthalidone was studied in double blind fashion over an 8 week period in patients who presented with untreated mild hypertension. One hundred and thirty four patients completed this multicentre, family practice study. After 2 week's medication, a decline in blood pressure was noted in all dosage groups and this was maximal by 4 weeks. At 8 weeks all doses of chlorthalidone induced a significant reduction in both systolic and diastolic blood pressures (mean −18 and −10 mmHg respectively). Amongst the 4 dosage groups, no differences in response were noted resulting in a flat dose response curve. During the study, mean blood urea and serum uric acid rose whilst serum potassium fell, the urea and potassium being least affected in the 25 mg dosage group. As the dosage of chlorthalidone increased, so the tendency for abnormal laboratory values increased. Unwanted effects sought during the study were relatively few in number. No clear dose response relationship was evident although the positive responses in the 25 mg dosage group were less than in the higher dosages. These results suggest that 25 mg chlorthalidone is the optimum dosage for initiation of therapy in patients with mild to moderate hypertension. This dosage is associated with less adverse biochemical changes and unwanted effects than the higher dosages studied.
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  • 44
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    The pharmacokinetics of trichlormethiazide in hypertensive patients with normal and compromised renal function (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 453-457 
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    ISSN: 1432-1041
    Keywords: diuretics ; trichlormethiazide ; hypertension ; pharmacokinetics ; renal insufficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of trichlormethiazide (TCZ) was studied in twelve patients after a single 4 mg dose. Seven patients had normal renal function with creatinine clearances greater than 90 ml/min. Five patients had compromised renal function with creatinine clearances averaging 48±29 ml/min. The TCZ plasma half life and area under the plasma concentration-time curve (AUC) were significantly greater in patients with impaired function, compared to patients with normal renal function. There were no significant differences between the two patient groups in terms of either rate of drug absorption or total urinary recovery of unchanged drug. Furthermore, there was no correlation between peak drug levels or AUC and renal excretion of water or electrolytes.
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  • 45
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    Combination therapy in hypertension (1981)
    Springer
    European journal of clinical pharmacology 21 (1981), S. 1-8 
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    ISSN: 1432-1041
    Keywords: hypertension ; combination therapy ; population survey ; drug treatment ; prescription patterns ; population incidence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a cross-sectional study, antihypertensive drug treatment was studied in a representative population sample of people aged 30–64 years, using a combination of postal survey, personal interview, clinical assessment and drug prescriptions. 11% of the men and 16% of the women were currently taking antihypertensives; 54% of patients used one, 38% used two, and 8% used three or more preparations. Men used slightly more drugs than women. Diuretics were used by 62% and betablockers by 49% of the sample population. Fixed combinations of thiazides and potassium-sparing agents formed 70% of all diuretic preparations used. Only 12% of the patients used fixed antihypertensive combinations, of which over half were diuretic-reserpine-vasodilator combinations; women and older patients used them most often. The most common freely combined preparations were diuretics and betablockers, which formed almost half of all two-drug combinations, and were also present in 70% of all triple combinations. Adequate control of blood pressure (DBP 〈100 mmHg) was achieved by slightly under 50% of the patients, the BP of women being more adequately controlled than that of men. Differences in BP control were found between the different drugs and combinations. Antihypertensive combination therapy is important in successful treatment, but we still cannot be sure whether fixed combination preparations or, as in this study, free combinations of marketed preparations are better alternatives for treatment.
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  • 46
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    Sotalol and metoprolol comparison of their anti-hypertensive effect (1981)
    Springer
    European journal of clinical pharmacology 21 (1981), S. 87-92 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; metoprolol ; sotalol ; comparison ; plasma levels ; serum uric acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 28 patients, aged 35–62 years, with uncomplicated hypertension, entered a double-blind, crossover study, in which the effects of single daily doses of sotalol and metoprolol were compared. Both drugs exerted a clinically useful anti-hypertensive effect as monotherapy, or in combination with a thiazide diuretic. No significant difference in hypotensive effects was noted between the two beta-blocking agents, when the dose was titrated to an optimal clinical effect. Treatment with sotalol and metoprolol was associated with a clinically insignificant increase in serum uric acid concentration. The side-effects observed were few, and in only two cases was therapy discontinued. We regard both sotalol and metoprolol as useful anti-hypertensive drugs.
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  • 47
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    The response to the angiotensin antagonist saralasin in predicting therapeutic outcome in hypertension treated with frusemide (1981)
    Springer
    European journal of clinical pharmacology 21 (1981), S. 165-168 
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    ISSN: 1432-1041
    Keywords: frusemide ; saralasin ; hypertension ; reninangiotensin ; sodium ; diet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The use of tests of the renin-angiotensin system for predicting antihypertensive responses to frusemide combined with dietary sodium deprivation was evaluated in eighteen patients with severe hypertension. No relationship could be shown between changes in blood pressure induced by the angiotensin analogue, saralasin, and the short-term or long-term therapeutic effects of diuretic- and diet-induced sodium depletion. Mean values for saralasin response and initial plasma renin activity in eight patients whose blood pressure was adequately controlled by therapeutic sodium depletion were closely similar to those obtained in the remaining ten patients, who proved refractory to this treatment.
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  • 48
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    Antihypertensive effect of fractionated sublingual administration of nifedipine in moderate essential hypertension (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 161-164 
    Details
    ISSN: 1432-1041
    Keywords: nifedipine ; hypertension ; blood pressure ; heart rate ; plasma renin activity ; aldosterone ; clinical trial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The magnitude and duration of the antihypertensive effect of nifedipine were studied in 7 cases of moderate essential hypertension. In a double-blind crossover study, nifedipine 10 mg or a placebo were administered sublingually 4 times a day for 2 days, and the results were compared. Each dose of nifedipine reduced systolic and diastolic blood pressure by 14% both in the supine and upright positions. The antihypertensive action lasted for about 3 h and it was not cumulative. The reduction in blood pressure was associated with a temporary increase in heart rate. Administration of nifedipine 10 mg did not significantly raise plasma renin activity or plasma aldosterone. The drug was well tolerated and no side effects were detected.
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  • 49
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    Pharmacokinetics of atenolol in hypertensive subjects with and without co-administration of chlorthalidone (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 333-337 
    Details
    ISSN: 1432-1041
    Keywords: atenolol ; chlorthalidone ; hypertension ; chronic treatment ; co-administration ; plasma half-life ; urine half-life
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of atenolol with and without the co-administration of chlorthalidone were studied in five hypertensive subjects. Concomitant administration of chlorthalidone appears to have little if any effect on the pharmacokinetics of atenolol during treatment for 7 days. The atenolol elimination half-lives were 6.7±1.1 and 6.3±0.9 h, respectively, with and without chlorthalidone. Two healthy volunteers also received a single 50 mg oral dose of chlorthalidone. Their blood profiles and pharmacokinetics were similar to those observed in hypertensive subjects, but a statistically significant difference (p〈0.01) was found between the urinary excretion half-lives of chlorthalidone. This difference may be because chronic administration of the drug caused saturation of red cell binding.
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  • 50
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    Antihypertensive and hormonal effects of single oral doses of Captopril and Nifedipine in essential hypertension (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 157-161 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; captopril ; nifedipine ; plasma renin activity ; aldosterone ; vasopressin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a single-dose crossover study Captopril (SQ 14225), 1 mg/kg body weight, and Nifedipine (Bay a 1040) 20 mg were administered orally to 12 hospitalized patients with essential hypertension (Stage 1 or 2, W. H. O.). Both drugs significantly reduced blood pressure, but each dose acted differently: the mean maximum arterial pressure reduction was faster and greater with Nifedipine than with Captopril: −23±2% at 37±15 min and −17±1% at 86±25 min, respectively. Captopril inhibited angiotensin II and aldosterone production, but did not accelerate heart rate or stimulate vasopressin release. Nifedipine stimulated vasopressin release and increased heart rate, but the renin angiotensin aldosterone system was not significantly affected. The blood pressure reduction was related to the initial level of activation of the renin angiotensin system only for Captopril. The blood pressure reduction induced by one drug was not related to that produced by the other in the same patient.
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  • 51
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    Use of labetalol in hypertensive patients during discontinuation of clonidine therapy (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 237-240 
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    ISSN: 1432-1041
    Keywords: labetalol ; clonidine ; hypertension ; adverse effects ; plasma catecholamines ; plasma cAMP ; withdrawal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Eleven hypertensive patients in whom clonidine therapy had to be discontinued, were treated prophylactically with labetalol, in order to avoid a possible hypertensive crisis. Most of the known side effects, which are consistent with the withdrawal phenomenon were observed, e.g. tremor, insomnia and apprehension, but headaches and flushing did not occur. Blood pressure levels remained unchanged, despite up to a 20-fold increase in plasma catecholamines. The lack of change in serial measurements of plasma cyclic AMP level appears to indicate that adequate adrenergic blockade was induced by labetalol. Since labetalol is a potent anti-hypertensive drug, and is also effective in avoiding a possible hypertensive crisis due to withdrawal of clonidine, we propose to use it as the drug of choice whenever discontinuation of clonidine therapy is indicated.
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  • 52
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    Correlation between propranolol in plasma and urine, renin-aldosterone system and blood pressure in essential hypertension (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 251-258 
    Details
    ISSN: 1432-1041
    Keywords: aldosterone ; hypertension ; propranolol ; blood pressure ; plasma level ; renin ; urine level
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Thirty patients with mild or moderate essential hypertension, and a fixed elevation of diastolic blood pressure, were randomly allocated to three groups and treated with propranolol 40 mg×4 (Group 1), 80 mg×4 (Group 2) and 160 mg×4 (Group 3). Blood pressure (BP), pulse rate (PR), plasma renin activity (PRA), plasma aldosterone concentration (PAC), total plasma propranolol (tPP), free plasma propranolol (fPP), and 24 h urinary propranolol excretion (UP) were determined at the end of four consecutive periods: (A) after four weeks without any treatment; (B) after two to three weeks during which the propranolol dose was gradually increased to the intended level; (C) after four weeks, and (D) after eight weeks of unchanged treatment. The maximum reduction in diastolic BP occurred after period B, and in systolic BP after Period C, for Groups 2 and 3, and for all groups together; for Group 1, however, the maximum diastolic BP reduction was first seen after period C. PR was reduced to the same level in all groups after period B. After period B, PRA and PAC fell in all groups, and remained reduced during C and D in Group 1. After periods C and D, PRA and PAC in Groups 2 and 3 did not differ significantly from the levels after period A; tPP, fPP and UP were significantly correlated with the propranolol dose, and were lowest in Group 1 and highest in Group 3; UP was negatively correlated with systolic but not diastolic BP in Periods B, C and D. In contrast neither fPP nor tPP were correlated with systolic or diastolic BP. There was no significant correlation between PRA, PAC and changes in PRA or PAC on the one hand and tPP, fPP, UP, BP or changes in BP on the other. It was concluded that propranolol effectively reduced BP, but diastolic BP reduction was most rapidly obtained at 320 and 640 mg daily, that the activity of the renin-aldosterone system was initially suppressed in all groups, but for unknown reasons it increased towards the control level after seven to eleven weeks of therapy with 320 and 640 mg/day, and that the reduction in systolic BP increased with higher doses of propranolol and with increasing urinary propranolol excretion.
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    Effect of minoxidil on sympathetic nervous activity in clonidine-treated hypertensive patients (1981)
    Springer
    European journal of clinical pharmacology 20 (1981), S. 259-262 
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    ISSN: 1432-1041
    Keywords: clonidine ; minoxidil ; hypertension ; sympathetic nervous activity ; plasma renin activity ; cardiovascular responses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of clonidine and minoxidil on sympathetic nervous activity has been studied in 10 patients with accelerated or resistant hypertension. Clonidine 150 to 900 µg/day caused a significant decrease in blood pressure of 18.6 mm Hg, of heart rate 16.4 beats/min, or plasma renin activity 1.13 ng/ml·h, and of urinary noradrenaline excretion 11.55 µg/day, and a significant lengthening of the pre-ejection period of 12.4 ms. Minoxidil 5 to 22.5 mg/day caused a further significant decrease in blood pressure of 24.2 mm Hg, and significant increases in heart rate 8.2 beats/min, plasma renin activity 1.68 ng/ml·h, and of urinary noradrenaline excretion 5.0 µg/day, and a significant shortening of the pre-ejection period of 20.6 ms. Neither clonidine nor minoxidil altered plasma dopamine β-hydroxylase activity or the cardiovascular responses to treadmill exercise. It is concluded that clonidine is a useful alternative agent to block a minoxidil-induced increase in sympathetic nervous activity.
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  • 54
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    Use of fixed doses of beta blocking drugs in the treatment of hypertension (1981)
    Springer
    European journal of clinical pharmacology 21 (1981), S. 93-96 
    Details
    ISSN: 1432-1041
    Keywords: atenolol ; penbutolol ; hypertension ; beta-blockers ; intrinsic sympathomimetic activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Atenolol 100 mg and penbutolol 40 mg given once a day were both effective in controlling moderate hypertension, as judged by a randomised controlled, double-blind trial in 45 patients treated for six weeks. Both drugs significantly reduced the resting supine and erect blood pressures. No serious adverse effects could be attributed to either drug. Bradycardia occurred more frequently with atenolol than with penbutolol. Penbutolol, which possesses intrinsic sympathomimetic activity, may be useful in the treatment of patients in whom some other beta-blocker has failed to bring about adequate control of the blood pressure, despite marked bradycardia.
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    The ultrastructure of cell wall formation and of gamma particles during encystment of Allomyces macrogynus zoospores (1980)
    Springer
    Archives of microbiology 128 (1980), S. 179-189 
    Details
    ISSN: 1432-072X
    Keywords: Allomyces ; Zoospores ; Cell wall ; Chitin ; Gamma particle ; Encystment ; Electron microscopy ; Calcofluor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Structural changes during cell wall formation by populations of semisynchronously germinating zoospores were studied in the water mold Allomyces macrogynus. Fluorescence microscopy using Calcofluor white ST (which binds to β-1,4-linked glycans) demonstrated that Calcofluor-specific material was deposited around most cells between 2–10 min after the induction of encystment (beginning when a wall-less zoospore retracts its flagellum and rounds up). During the first 15 min of encystment there was a progressive increase in fluorescence intensity. Ultrastructural analysis of encysting cells showed that within 2–10 min after the induction of encystment small vesicles 35–70 nm diameter were present near the spore surface, and some were in the process of fusing with the plasma membrane. The fusion of vesicles with the zoospore membrane was concomitant with the appearance of electron-opaque fibrillar material outside the plasma membrane. Vesicles similar to those near the spore surface were found within the gamma (γ) particles of encysting cells. These particles had a crystalline inclusion within the electron-opaque matrix. During the period of initial cyst cell wall formation numerous vesicles appeared to arise at the crystal-matrix interface. Approximately 15–20 min was required for the cell wall to be formed. We suggest that the initial response of the zoospore to induction of encystment is the formation of a cell wall mediated by the fusion of cytoplasmic vesicles with the plasma membrane.
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    Relative levels of guanosine 5′-diphosphate 3′-diphosphate (ppGpp) in some N2 fixing bacteria during derepression and repression of nitrogenase (1981)
    Springer
    Archives of microbiology 128 (1981), S. 341-342 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Regulation ; Guanosine 5′-diphosphate 3′-diphosphate (ppGpp)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Addition of ammonium to N2 fixing cultures of Azotobacter vinelandii, Klebsiella pneumoniae and Clostridium pasteurianum rapidly reduced the intracellular levels of guanosine 5′-diphosphate 3′-diphosphate (ppGpp) by 70–90%. This change might reflect a regulatory role of ppGpp in nitrogen metabolism.
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    URL: http://dx.doi.org/10.1007/BF00422542
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    Freeze fracture studies of reaction centers from Rhodospirillum rubrum in chromatophores and liposomes (1981)
    Springer
    Archives of microbiology 130 (1981), S. 125-128 
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    ISSN: 1432-072X
    Keywords: Rhodospirillum rubrum ; Chromatophores ; Reaction centers ; Liposomes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In freeze-fractures of chromatophores of Rhodospirillum rubrum the reaction centers are seen as hexagonal arranged particles of 13 nm diameter with a density of around 5,500 particles per μm2. Similar regions on the cytoplasmic membrane suggest that these parts are the prospective invagination sites. Isolated reaction centers are easily incorporated into liposomes. In freeze fractures of liposomes particles similar in shape and size, although less dense as in chromatophores are observed. In negative staining much smaller units of only 5 nm in diameter are found indicating that reaction centers occur in the membrane as tri- or tetramers. There is a strong correlation between particle density in chromatophores and titratable reaction centers remaining in these membranes after extraction of reaction centers by detergents; both values are in good agreement with the yield of reaction centers at a given detergent concentration.
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    Evidence for supercoiling in the DNA of bacteriophage heads (1980)
    Springer
    Archives of microbiology 126 (1980), S. 277-283 
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    ISSN: 1432-072X
    Keywords: Bacteriophage ; Myxococcus ; λ ; Superooiled DNA ; Cross-linking ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA was partially released from the heads of myxococcus phages and also coliphage λ and examined by electron microscopy by a modification of the Kleinschmidt technique, in which water was used as hypophase. DNA emerged from the heads in patterns suggestive of newly relaxed supercoils. The unreleased DNA appeared to occupy discrete regions in the head. Some closed circles were released from λ heads. When NaCl solution was used as hypophase, the DNA was observed either released from the tail or from the head, in the latter case, supercoiled regions were observed. When NH4OAc solution was used as hypophase, tightly wound structures were released from λ heads; these fields also contained supercoiled circles. The presence of constrained supercoiled domains in newly released phage DNA was confirmed by observing the effects of ethidium bromide on its conformation. Treatment of phage with nitrogen mustard, a bifunctional alkylating agent, preserved supercoiled domains, even when the phage were lysed over water as hypophase. Further experiments suggested that phage inactivation by nitrogen mustard is largely due to restraint of the supercoiled, native, tertiary structure and that DNA-protein cross-linking may be involved in this reaction. The implications of these findings for the conformation of phage DNA in vivo are discussed and a new model for the winding of DNA in phage heads is proposed.
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    URL: http://dx.doi.org/10.1007/BF00409932
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    The occurrence of coryneform bacteria in the leaf cavity of Azolla (1980)
    Springer
    Archives of microbiology 127 (1980), S. 163-165 
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    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Arthrobacter ; Corynebacterium ; Anabaena azollae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Coryneform bacteria were found associated with the nitrogen fixing blue-green alga, Anabaena azollae in the leaf cavity of Azolla caroliniana. Plate counts indicated ca. 7,400±1,900 bacterial cells per mature leaf cavity or approximately 1 bacterial cell for every algal cell. No other type of bacterium was found in these cavities.
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    Antigenic differences between Anabaena azollae fresh from the Azolla fern leaf cavity and free-living cyanobacteria (1980)
    Springer
    Archives of microbiology 128 (1980), S. 126-129 
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    ISSN: 1432-072X
    Keywords: Fluorescent antibody staining ; Nitrogen fixation ; Symbiosis ; Anabaena azollae ; Azolla caroliniana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fluorescent antibody staining indicated differences in surface antigenicity in Anabaena azollae cells fresh from the leaf cavities of the fern, Azolla caroliniana, and algae which were isolated and subcultured from this fern. Such results suggest that either changes in antigenicity occur in this phycobiont during culturing or that isolation selects for an antigenically different mutant strain capable of in vitro growth.
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    URL: http://dx.doi.org/10.1007/BF00422316
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    Relative numbers of selected bacterial forms in different regions of the cockroach hindgut (1981)
    Springer
    Archives of microbiology 129 (1981), S. 129-134 
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    ISSN: 1432-072X
    Keywords: Cockroach ; Hindgut ; Distribution ; Microbial morphotypes ; Transmission ; Electron microscopy ; Statistical analysis ; Eublaberus posticus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relative numbers of fourteen microbial morphotypes in transmission electron micrographs of the hindgut of a cockroach, Eublaberus posticus, were counted and their distribution was analyzed statistically. The microbiota of three wall-associated regions (the anterior paunch, the posterior paunch, and the black band region) was clearly different from that of the gut lumen. The three wall fractions were also significantly different from each other. Only one of the fourteen types, prosthecate bacteria, appeared to be distributed randomly in the four fractions. The five main wall-associated morphotypes individually constituted up to 41% of the microbes in some micrographs. They included one type with the characteristic morphology of Methanospirillum. Six morphotypes rarely made up over 2% of the population, but were consistently present. The numbers of the remaining three morphotypes were quite variable between micrographs and between individual insects, but when present often made up 5–10% of the population.
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    The uptake and hydrolysis of disaccharides by fast-and slow-growing species of Rhizobium (1981)
    Springer
    Archives of microbiology 129 (1981), S. 238-239 
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    ISSN: 1432-072X
    Keywords: Rhizobium ; Disaccharide ; Bacteroid ; Transport ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Slow growing strains of rhizobia appear to lack both uptake systems and catabolic enzymes for disaccharides. In the fast-growing strains of rhizobia there are uptake mechanisms and catabolic enzymes for disaccharide metabolism. In Rhizobium leguminosarum WU 163 and WU235 and R. trifolii WU290, sucrose and maltose uptake appears to be constitutive whereas in R. meliloti WU60 and in cowpea Rhizobium NGR234 uptake of these disaccharides is inducible. There is evidence that there are at least two distinct disaccharide uptake systems in fast-growing rhizobia, one transporting sucrose, maltose and trehalose and the other, lactose. Disaccharide uptake is via an active process since uptake is inhibited by azide, dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone but not by arsenate. Bacteroids of R. leguminosarum WU235 and R. lupini WU8 are unable to accumulate disaccharides.
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    Entrapment and lysis of the cyanobacterium Phormidium luridum by aqueous colonies of Myxococcus xanthus PCO2 (1981)
    Springer
    Archives of microbiology 129 (1981), S. 285-294 
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    ISSN: 1432-072X
    Keywords: Biological control ; Cyanobacteria ; Electron microscopy ; Entrapment ; lysis ; Myxococcus ; Phormidium ; Spherule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A Myxococcus xanthus isolate from a farm drainage ditch, designated strain PCO2, is capable of rapidly inducing lysis of both agar and liquid-grown cultures of the cyanobacterium, Phormidium luridum, var. olivacea. Microscopic studies of the predator-prey interaction demonstrate that lysis of the cyanobacterium occurs within clumps and spherules formed by the cells of M. xanthus PCO2. In the earliest stage, one sees the formation of irregular microclumps of bacteria and cyanobacterial filaments. As these clumps mature, colonies 1 to 6 mm in diameter develops. The center of these densely green colonies contains cyanohacteria in various stages of degradation, while the periphery is almost exclusively a tightly woven mass of myxobacterial cells. Electron microscopy shows that long extrusions from the outer membrane of the M. xanthus PCO2 cells are involved in the formation both of initial clumps and of mature colonial spherules. These extrusions appear to efficiently entangle the cyanobacterial filaments in the culture environment. Predator-to-prey ratios of 1/10, 1/100 and 1/1,000 have resulted in cyanobacterial lysis. Because the entrapment and lysis of P. luridum filaments by M. xanthus PCO2 appears to be independent of any other heterotrophic nutritional requirement, as well as of environmental agitation, this system has potential as a biological control technique for undesirable aquatic cyanobacteria.
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    Regulation of nitrogenase messenger RNA synthesis and stability in Klebsiella pneumoniae (1981)
    Springer
    Archives of microbiology 130 (1981), S. 38-43 
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    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Gene expression ; Regulation ; Messenger RNA ; Transcription ; Klebsiella pneumoniae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogenase messenger RNA synthesis in Klebsiella pneumoniae was determined by labelling cells with (3H)uracil and isolating total RnA, which was then hybridized to filterbound recombinant plasmid pSA30 DNA carrying the nitrogenase structural genes nifH, D, and K. Derepression of nitrogenase mRNA starts 1.5 h before the onset of nitrogenase activity (as measured by acetylene reduction). Exposure of nif-derepressed cultures to either NH 4 + , air, or high temperatures (39° C) results in a rapid decrease of the synthesis rates both of nitrogenase mRNA and nitrogenase polypeptides. Nitrogenase mRNA is remarkably stable. After blocking transcription with rifampicin, hybridizable and actively translatable nitrogenase mRNA survives with an average half-life of 18 min. Half-lives are considerably shorter when rifampicin-inhibited cultures are simultaneously shifted to conditions which are non-permissive for nitrogenase synthesis, pointing to some posttranscriptional influence on nitrogenase mRNA stability. In all experiments performed there was no evidence for uncoupling of nitrogenase mRNA synthesis from nitrogenase mRNA translation, indicating that nitrogenase synthesis is regulated solely by transcriptional control.
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    Electron microscopy and X-ray microanalysis of a halophilic leptospire (1981)
    Springer
    Archives of microbiology 130 (1981), S. 339-343 
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    ISSN: 1432-072X
    Keywords: Leptospira ; Halophilic ; Electron microscopy ; X-ray analysis ; Inclusions ; Cytoplasmic tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology of cells of strain Muggia, a slightly halophilic leptospire, was examined by the negative staining technique. The ultrastructure of the cells was rather similar to that of cells of Leptonema illini, i. e. the cells possessed cytoplasmic tubules. The basal complex of their flagella, however, was similar to the corresponding part of flagella on Gramnegative bacteria. The interior of the cells was densely packed with inclusions, except for the two outermost wavelengths at each end where these inclusions were absent. X-ray microanalysis showed that the inclusions contained sodium and chlorine as their main constituents. The inclusions disappeared upon storage of the cultures at room temperature.
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    Nitrogen fixation associated with a hotspring green alga (1980)
    Springer
    Archives of microbiology 124 (1980), S. 161-167 
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    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Photosynthesis ; Green alga ; Chl a and b ; DCMU ; Light and O2 dependency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A unicellular alga which can grow in the light without a combined nitrogen source was isolated from a hot spring. The cells were almost spherical, usually 5–10 μm in diameter. Absorption spectra of the watersoluble pigments and of the acetone-extracted ones revealed the existence of chlorophyll a and b and the absence of phycobilins. Thin sections examined by electron microscopy revealed an eukaryotic organization with features typical of the coccoid green algae (the Chlorococcales). Cells divided by internal cytokinesis and subsequent liberation of daughter cells from the parental wall, in a way similar to Chlorella. The alga reduced acetylene to ethylene and incorporated 15N2 into cell protoplasm when incubated in a low oxygen atmosphere. Nitrogenase activity was light-dependent, microaerophilic and thermophilic. Although the association of symbiotic nitrogen fixing prokaryotes with the cells may still be possible, any such organisms have not so far been detected.
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    Immunoferritin labeling of respiratory nitrate reductase in membrane vesicles of Bacillus licheniformis and Klebsiella aerogenes (1980)
    Springer
    Archives of microbiology 127 (1980), S. 39-46 
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    ISSN: 1432-072X
    Keywords: Immunoferritin labeling ; Electron microscopy ; Membrane vesicles ; Nitrate reductase ; Bacillus licheniformis ; Klebsiella aerogenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The indirect immunoferritin labeling method was used to localize the membrane-bound respiratory nitrate reductase in membrane vesicles and protoplasts or spheroplasts of Bacillus licheniformis and Klebsiella aerogenes, respectively. For a comparison of the labeling of the various vesicle preparations, which differed not only in size but also in the percentage of inside-out orientation, a quantification of the results was needed to circumvent the problem of non-specifically bound ferritin. From the results the sidedness of the nitrate reductase in the cytoplasmic membrane of the abovementioned bacteria was determined as being cytoplasmic in B. licheniformis and as transmembranous in K. aerogenes.
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    Expression of klebsiella his and nif genes in serratia marcescens, Erwinia herbicola and Proteus mirabilis (1980)
    Springer
    Archives of microbiology 127 (1980), S. 115-118 
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    ISSN: 1432-072X
    Keywords: Proteus mirabilis ; Serratia marcescens ; Erwinia herbicola ; Nitrogen fixation ; nif genes ; his genes ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plasmid pRD1, an R plasmid of the P incompatibility group which carries his and nif genes from Klebsiella pneumoniae in addition to drug resistance markers derived from RP4, was transferred to His- mutants of Serratia marcescens, Erwinia herbicola and Proteus mirabilis. His+ transconjugants were obtained at low but different frequencies according to recipient genus. Transconjugants all acquired the drug resistance, and were Nif+ in S. marcescens and E. herbicola, having acetylene-reducing activities of the same order of magnitude as the parent K. pneumoniae and fixing 15N2. No evidence for nif expression in P. mirabilis transconjugants was obtained though the nif genes were present.
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    Chemical composition and ultrastructure of cellular and extracellular Moraxella glucidolytica lipopolysaccharides (1980)
    Springer
    Archives of microbiology 128 (1980), S. 12-18 
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    ISSN: 1432-072X
    Keywords: Moraxella glucidolytica ; Electron microscopy ; Lipopolysaccharide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cellular (LPS I) and extracellular (LPS II) lipopolysaccharide were isolated from Moraxella glucidolytica cells grown on ethanol and from the culture fluid, respectively. Both LPS were toxic when injected to mice and chick embryos. These LPS contained glucose, galactose, glucosamine, galactosamine, 2-keto-3-deoxyoctonate and lipids. By permethylation studies, glucose was found to be linked (1→6) and (1→3) in LPS I and only (1→6) in LPS II. Galactose was the terminal non-reducing sugar. Branching occurred at positions 3 and 4 of galactose residues. LPS I was rich in α- and β-hydroxylauric and α-hydroxymyristic acids and LPS II contained mainly stearic and α-hydroxymyristic acids. LPS I was detoxified by mild acid and alkaline treatments. It was also dissociated by sodium deoxycholate and chromatographed on Sephadex G-75. The main fraction was reassociated by removing the surfactant by dialysis. The morphology of LPS I and LPS II was examined by electron microscopy. LPS I (original and reassociated fractions) consisted exclusively of ribbons while LPS II contained ribbons and vesicles.
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    Transformations of inorganic nitrogen by Azospirillum spp. (1981)
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    Archives of microbiology 130 (1981), S. 96-100 
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    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Nitrate respiration ; Denitrification ; Assimilatory nitrate reduction ; Dissimilatory nitrate reduction ; Acetylene reduction ; Azospirillum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Azospirillum spp. participate in all steps of the nitrogen cycle except nitrification. They can fix molecular nitrogen and perform assimilatory nitrate reduction and nitrate respiration. Culture conditions have been defined under which nitrate is used both as terminal respiratory electron acceptor and as nitrogen source for growth. Nitrate and, possibly to a very limited extent, nitrite, but not sulfate, iron or fumarate support anaerobic respiration. Under anaerobic conditions, nitrate can also supply energy for nitrogen fixation but without supporting growth. Nitrate-dependent nitrogenase activity lasts only for 3–4 h until the enzymes of assimilatory nitrate reduction are synthesized. Nitrite accumulates during this period and inhibits nitrogenase activity at concentrations of about 1 mM.
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    Molecular weight and quaternary structure of ribulose bisphosphate carboxylase from the cyanobacterium, Synechococcus sp. (1981)
    Springer
    Archives of microbiology 130 (1981), S. 344-348 
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    ISSN: 1432-072X
    Keywords: Ribulose bisphosphate carboxylase ; Quaternary structure ; Molecular weight ; Electron microscopy ; Cyanobacteria ; Synechococcus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ribulose bisphosphate (RuP2) carboxylase from the marme cyanobacterium, Synechococcus sp., comprised both large (57,000 dalton) and small (12,000 dalton) subunits. The undissociated, purified enzyme was considerably smaller than the spinach enzyme when compared by pore-gradient electrophoresis, gel filtration and density-gradient centrifugation. This suggested that the cyanobacterial enzyme might have a hexameric (L6S6) subunit structure, unlike the enzymes from spinach and many other organisms which are octamers (L8S8). However, the molecular weight of the Synechococcus enzyme was measured by equilibrium sedimentation and found to be 530,000, which is within the range observed for L8S8-type enzymes. Furthermore, electron microscopic studies of negatively stained preparations of both the native enzyme, and a preparation depleted of 87% of its small subunits by repeated mild-acid precipitation, revealed four-fold symmetry characteristic of an octameric, cubical structure. Synechococcus RuP2 carboxylase therefore must be an L8S8 octamer and its anomalous pore-penetration behaviour may be due to an asymmetric shape. Some support for the latter possibility was provided by electron miscoscopic observations of two different types of images which may be different views of the molecule in two planes.
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    Ultrastructure of Ascodichaena rugosa on beech bark (1980)
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    Archives of microbiology 126 (1980), S. 87-95 
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    ISSN: 1432-072X
    Keywords: Ascodichaena ; Beech bark ; Electron microscopy ; Host-fungus relationship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ascodichaena rugosa Butin is a corkinhabiting fungus, found frequently on the bark of Fagus sylvatica L. The hyphae of the fungus are distributed solely in the phellem cells, stopping their growth in the last-formed cork cell layer. The cell to cell invasion is effected by penetration hyphae, causing no extensive dissolution of the cork wall. Electron microscopical observations revealed fine structural details of the fruit bodies and of the intracellular hyphae. Of special interest were the finger-like hyaline hyphae in the last-formed layer of cork cells, which are interpreted as haustoria on the basis of the fine structure both of hyphae and host cells. This situation is considered as reflecting a parasitic relationship of Ascodichaena to beech bark. The activity of the fungus led also to the increased production of cork cells, perhaps related to the nutrient supply of the fungus.
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    Cytological localization of α-MSH, ACTH and β-endorphin in the pars intermedia of the cichlid teleost Sarotherodon mossambicus (1981)
    Springer
    Cell & tissue research 215 (1981), S. 625-633 
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    ISSN: 1432-0878
    Keywords: Teleost ; Pars intermedia ; Immunocytochemistry ; PAP-technique ; MSH ; ACTH ; Endorphin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars intermedia of S. mossambicus contains two different endocrine-cell types. The predominant cell type is lead-haematoxyline-positive and assumed to synthesize MSH and related peptides. The second cell type is PAS positive and its function and product(s) are unknown. Staining of light-microscopic and ultrathin sections with antisera against α-MSH, ACTH 1–24 and human β-endorphin revealed that only the lead-haematoxyline-positive cells of the pars intermedia react with these antisera, and that the secretory granules of these cells contain compounds that were immunoreactive to all three antisera. These findings are in line with the hypothesis that α-MSH, ACTH and endorphins are derived from the same precursor molecule. No specific reaction with one of the antisera could be detected in the PAS positive cells.
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    Evidence for somatostatin, gastrin and pancreatic polypeptide-like substances in the mucosa cells of the gut in fishes with and without stomach (1981)
    Springer
    Cell & tissue research 216 (1981), S. 193-203 
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    ISSN: 1432-0878
    Keywords: Digestive tract ; Fish ; Gastrin-immunoreactive cells ; Pancreatic polypeptide-immunoreactive cells ; Somatostatin-immunoreactive cells ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gastrin, pancreatic polypeptide and somatostatin immunoreactive cells in the gut of two fish with stomachs (perch and catfish) and a stomachless fish (carp) were studied by immunocytochemistry. In the gastric mucosa of perch and catfish, cells showing gastrin and somatostatin-like immunoreactivity are found, scattered among the surface mucous cells and mucous neck cells. No pancreatic polypeptide (P.P.) immunoreactive cells are detected in the gastric mucosa. Cells showing gastrin and P.P.-like immunoreactivity are observed in the intestinal mucosa of perch, catfish and carp. In this location no somatostatin immunoreactive cells are found.
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    Immunocytochemical localization of somatostatin-containing neurons in the brain of Rana temporaria (1980)
    Springer
    Cell & tissue research 205 (1980), S. 43-53 
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    ISSN: 1432-0878
    Keywords: Brain ; Rana temporaria ; Somatostatin-containing neurons ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The brain of the frog Rana temporaria was studied at the light microscopic level with the use of a double immunocytochemical staining method. The telencephalon, diencephalon and rhombencephalon contain somatostatin perikarya and fibers. In the telencephalon, the location of the somatostatin neurons largely corresponds to that of mammals. In the hypothalamus, the somatostatin perikarya are located in and near the magnocellular preoptic nucleus and also in the pars ventralis of the tuber cinereum. Like the somatostatin neurons of the rat hypothalamus, they form a separate subpopulation, different from the neurons producing neurohypophysial hormones. In Rana, somatostatin neurons are also present in (as well as in the vicinity of) the subfornical organ, in the thalamus, the tectum opticum, the interpeduncular nucleus and the caudal end of the roof of the calamus scriptorius. A precise localization of the perikarya of most somatostatin fibers, including those found in the median eminence and the neural lobe, was not attained.
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    Phagocytosis of spermatozoa by the ovum of the domestic fowl, Gallus gallus at the time of fertilization (1980)
    Springer
    Cell & tissue research 206 (1980), S. 55-63 
    Details
    ISSN: 1432-0878
    Keywords: Phagocytosis ; Spermatozoa ; Ovum ; Fertilization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spermatozoa with intact acrosomes, as well as those coming into contact with the ovum at a smaller angle, and morphologically abnormal spermatozoa reach the plasma membrane of the ovum via an extensively dissolved zone of the inner layer of the vitelline membrane. This zone is assumed to be formed by overlapping of two or more tunnels formed by spermatozoa that had previously come into contact with the ovum. When a spermatozoon comes into contact with the plasma membrane of the ovum, many cytoplasmic processes extend outwards and cover it. Thereafter, the plasma membranes of the processes fuse, thereby phagocytizing the spermatozoon. It is assumed that the phagocytized spermatozoa cannot undergo transformation into male pronuclei and that they degenerate soon after phagocytosis.
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    Ca++-induced structural changes in photoreceptor microvilli of diptera (1980)
    Springer
    Cell & tissue research 206 (1980), S. 225-232 
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    ISSN: 1432-0878
    Keywords: Compound eye ; Photoreceptor membrane ; Electron microscopy ; Calcium-induced changes ; Artefacts ; Diptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When the compound eyes of the fly Lucilia are fixed for electron microscopy with glutaraldehyde in common buffer solutions, artefactual whorls are liable to be formed from the photoreceptor microvilli. The whorls result from two factors: (i) a prolonged time interval prior to osmication, such as the “overnight” primary fixation or wash at 4° C commonly used in studies of compound eyes; (ii) as little as 1–2 mM Ca++ in the primary fixative and wash solutions. Osmication after short (1 h) glutaraldehyde fixation at 4° C, or omission of Ca++ and addition of 2 mM EGTA, prevent whorl-formation. In the tipulid fly Ptilogyna, similar artefacts are produced, but are confined to the distal zone of the microvilli that sheds during turnover.
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    URL: http://dx.doi.org/10.1007/BF00232766
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    Scanning and transmission electron microscopic observations of the cloacal epithelia of the domestic fowl (1980)
    Springer
    Cell & tissue research 211 (1980), S. 83-93 
    Details
    ISSN: 1432-0878
    Keywords: Epithelium ; Cloaca ; Electron microscopy ; Hen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithela of the three divisions (coprodaeum, urodaeum, proctodaeum) of the cloaca of the hen, and of the excretory ducts (colon, ureter, vagina) which join the divisions, are described using light microscopy, and scanning and transmission electron microscopy. Each region of the cloaca has its typical epithelium. Special attention is focussed in this study on the boundaries between the different epithelia. The coprodaeal epithelium does not differ considerably from that of the colon; a transitional zone is not visible. Distinct border zones, however, are observed between the other regions (ureter — urodaeum; vagina — urodaeum and proctodaeum; urodaeum-proctodaeum; proctodaeum — cutis). Although the vaginal opening is generally thought to lie in the urodaeum, our investigations show that at the vaginal opening into the cloaca the ciliated epithelium changes, on one border to a secretory epithelium characteristic of the urodaeum and on the other border to that characteristic of the proctodaeum. These observations are discussed in relation to functional aspects.
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    URL: http://dx.doi.org/10.1007/BF00233725
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  • 79
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    Ultrastructural alterations of the pancreatic D cell in the domestic fowl following vagotomy (1980)
    Springer
    Cell & tissue research 211 (1980), S. 171-174 
    Details
    ISSN: 1432-0878
    Keywords: Pancreatic D cell ; Neural control ; Vagotomy ; Electron microscopy ; Fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to determine the neural control of pancreatic D cells, the pancreatic islets of the domestic fowl were examined electron microscopically from 1 to 28 days after abdominal vagotomy. Exocytotic release of many secretory granules from D cells occurred one day after vagotomy. Rough endoplasmic reticulum developed and formed an arrangement of concentric whorls in the cytoplasm of D cells after axotomy. The altered D cells were also characterized by the occurrence of many peculiar dense bodies in the apical cytoplasm at all time periods studied. These bodies varied in shape and size, containing several round vesicles. The D cells were extensively depleted of granules after the longer time periods following vagotomy. The present results provide new morphological evidence for the vagus-nerve control of D cells, which may regulate the activity of islet cells.
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    URL: http://dx.doi.org/10.1007/BF00233732
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  • 80
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    Fetal hypothalamic transplants in the third ventricle of the adult rat brain (1980)
    Springer
    Cell & tissue research 211 (1980), S. 191-206 
    Details
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Transplants ; Vasopressin ; Median eminence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Blocks of anterior hypothalamus were transplanted from 19 day-old fetuses of Wistar/Lewis rats into the third ventricle of adult male Brattleboro rats. Physiological changes in graft recipients and in sham-operated animals were monitored daily. Twenty days after surgery, the graft recipients and shamoperated animals were killed and their brains examined by correlative scanning and transmission electron microscopy. Host animals that exhibited both decreased polydipsia and increased urine concentration were found to have viable grafts within the third ventricle. The observed physiological changes suggested that synthesis and release of vasopressin occurred in the transplanted neurons. Grafts were well vascularized by vessels arising from the host hypothalamus. Neurons, with perikarya ranging from 8 to 30 μm in diameter, glial cells, and neurites were located throughout the transplants. A neurohemal contact zone, similar to that normally seen in the median eminence, could not be demonstrated in the grafts. The absence of complete glial and ependymal barriers indicates a relatively close association between cells in the transplants and the cerebrospinal fluid. A large increase in supraependymal neurons and their processes, including an eruption of neurons through the floor of the third ventricle in one animal, was observed in graft recipients but not in shamoperated animals.
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    URL: http://dx.doi.org/10.1007/BF00236442
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  • 81
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    Immunohistochemical localisation of substances reactive to antisera against α-and β-endorphin and met-enkephalin in the brain of Rana temporaria L. (1981)
    Springer
    Cell & tissue research 217 (1981), S. 79-92 
    Details
    ISSN: 1432-0878
    Keywords: α- and β-Endorphins ; Met-enkephalin ; Brain ; Immunocytochemistry ; Rana temporaria (Amphibia, Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the brain of Rana temporaria, two distinct systems reactive with α- and β-endorphin antisera, respectively, and with a met-enkephalin antiserum, have been detected immunohistochemically. Neurons reacting with α- and β-endorphin antisera are located (1) in the preoptic nucleus, and (2) in the pars ventralis of the tuber cinereum. Immunoreactive nerve fibres of both groups of perikarya end in the infundibular floor near the capillaries and the preoptico-hypophysial tract. Control reactions have shown that the immunoreactivity is suppressed by the corresponding antigens, but also by β-LPH. In view of these results the immunoreactive systems examined correspond to an α/β-endorphin system or a lipotropinergic system. Neurons reacting with the met-enkephalin antiserum are located in the paraventricular organ. Intense immunofluorescence was observed in the infundibular floor. Controls show that the labelling by met-enkephalin antiserum is exclusively suppressed by met-enkephalin. In the pituitary gland, on the other hand, α- and β-endorphin antisera reveal: 1) the MSH/ACTH-like cells of the pars intermedia and 2) the ACTH-like cells of the pars distalis.
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    URL: http://dx.doi.org/10.1007/BF00233828
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    Fine structure of ependymal cysts in and around the area postrema of the rat (1980)
    Springer
    Cell & tissue research 206 (1980), S. 303-318 
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    ISSN: 1432-0878
    Keywords: Area postrema, rat ; Ependyma ; Cyst ; Circumventricular organs ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peculiar cells forming cysts were observed in the area postrema and sometimes also in the choroid plexus and the tela chorioidea near the area postrema, and were studied in detail by electron microscopy. The cytological features of the cyst cell and its junctional relationship to neighboring cells imply that cyst cells are derived from ependymal and choroid epithelial cells. The cyst cells usually contact directly the perivascular spaces of postremal, choroidal or pial capillaries, where the cytoplasm is often considerably attenuated. The cystic lumen is commonly filled with a flocculent material. The limiting membrane of the cystic lumen, which frequently bears cilia and microvilli, has the same thickness as the surface cell membrane. In many cases, the cyst is surrounded by the cytoplasm of a single cell. In some cases, however, two cells participate in the formation of the cyst, although one is only a slender process and joined by a zonula occludens with the main cyst cell. Horseradish peroxidase (HRP) injected into the cerebrospinal fluid (CSF) space failed to enter the cystic lumen. A possible significance of the cyst in relation to the CSF and blood circulation was considered.
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    URL: http://dx.doi.org/10.1007/BF00232774
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    Immunofluorescence study of LRH-producing neurons in prosimians (Tupaia and Galago) (1980)
    Springer
    Cell & tissue research 206 (1980), S. 355-365 
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    ISSN: 1432-0878
    Keywords: LRH neurons ; Prosimians (Tupaia, Galago) ; Fluorescence ; microscopy ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Reactive LRH neurons were characterized in prosimians (Tupaia and Galago) by immunofluorescence using rabbit immunesera against unconjugated synthetic LRH, or LRH conjugated with bovine serum albumin. These neurons, which vary individually in number in one species, are mainly concentrated in the rostral hypothalamus (medial preoptic area and anterior hypothalamic area) and in the lamina terminalis. In contrast to the simians and man, immunoreactive perikarya were not routinely found in the mediobasal hypothalamus of the prosimians investigated in the present study. Reactive axons of the hypothalamo-hypophyseal tract are more numerous and conspicuous in the retrochiasmatic area and in the postinfundibular eminence. They give rise to radiating collaterals ending mainly around the capillaries of the primary portal plexus of the median eminence and of the infundibular stem (where they are generally more numerous). Reactive axons of the preopticoterminal tract, originating from the perikarya of the lamina terminalis, end around the capillaries of the vascular organ or below and between the ependymal cells lining its ventricular side. In Galago a small but very distinct tract of reactive axons runs under the optic chiasma, between the lamina terminalis and the ventral labium of the infundibulum. Very fine reactive extrahypothalamic axons were observed in the posterior part of the habenular ganglia, along the preamygdaloid portion of the stria terminalis and along the blood vessels of the parolfactory area.
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    Incorporation of 3H-oleic acid by the proximal convoluted tubule cells of the chick (Gallus domesticus) (1980)
    Springer
    Cell & tissue research 210 (1980), S. 447-459 
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    ISSN: 1432-0878
    Keywords: Lipid ; Kidney tubules, proximal ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lipid metabolism in the cells of the renal proximal convoluted tubules (PCT) was investigated in healthy fowls and in fowls with the Fatty Liver and Kidney Syndrome (FLKS). The tissue was fixed at 10–25 min intervals after intravenous injection of 3H-oleic acid. The distribution of autoradiographic grains was analysed by the “circle method”. In normal cells most of the silver grains were associated with the cytoplasmic organelles. Lipid droplets and Golgi elements had the highest specific activity relative to the nuclear activity, which was little above background level. Lysosome-like bodies and mitochondria had lower values. In the cells of the FLKS-affected birds a large proportion of the grains was located over the lipid droplets, which are abundant in this condition. The specific activity of the cytoplasmic organelles was barely 2-fold higher than the nuclear activity. The results suggest that there is a diminished incorporation of esterified fatty acids by the organelles of these cells and that the excess is transferred to the lipid droplets. The identity of low electron density particles observed in the PCT cells of severely affected birds is discussed.
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    URL: http://dx.doi.org/10.1007/BF00220201
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    Gut hormones in Salamandra salamandra (1980)
    Springer
    Cell & tissue research 211 (1980), S. 331-343 
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    ISSN: 1432-0878
    Keywords: Gut hormones ; Endocrine cells ; Electron microscopy ; Immunocytochemistry ; Peptidergic innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological, cytochemical and immunocytochemical methods were used in light and electron microscopical studies to demonstrate the presence of a neuroendocrine system in the gut of the urodele, Salamandra salamandra. Cytochemical stains capable of detecting peptide-producing endocrine cells demonstrate cells reacting with Masson's silver (argentaffin) method, Grimelius' argyrophil silver method, masked metachromasia method and the lead haematoxylin stain. Using antisera raised to a variety of mammalian gut peptides, cells containing bombesin-, gastrin-, somatostatin-, substance P- and glucagon-like immunoreactivity were identified; vasoactive intestinal polypeptide- and substance P-like immunoreactivities were found in nerve fibres in the submucous and myenteric plexus. No immunoreactivity was detected for motilin, gastric inhibitory polypeptide, cholecystokinin or secretin. The ultrastructure of the immunoreactive cells and nerves was revealed by the semithin/thin method. All the cells identified contained numerous electrondense secretory granules, which varied in their chracteristic morphological structure from one cell type to another. The evidence collected in this study indicates that a complex neuroendocrine system regulating gut function is present in this amphibian and may have developed prior to the emergence of the phylum.
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    Immunocytochemical demonstration of peptidergic neurons in the central nervous system of the pond snail Lymnaea stagnalis with antisera raised to biologically active peptides of vertebrates (1981)
    Springer
    Cell & tissue research 216 (1981), S. 273-291 
    Details
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Biologically active peptides ; Lymnaea stagnalis ; Neurohormone ; Neurotransmitter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Perikarya and nerve fibers were immunocytochemically identified in the central nervous system of the pond snail Lymnaea stagnalis by means of the unlabelled antibody enzyme method with antisera to 15 biologically active peptides of vertebrates: vasopressin, vasotocin, oxytocin, α-melanocyte stimulating hormone (α-MSH), met-enkephalin, somatostatin, glucagon, insulin, glucose-dependent insulinotropic peptide (GIP), vaso-active intestinal polypeptide (VIP), gastrin, secretin, pancreatic polypeptide (PP), Substance P, calcitonin. No immunostaining was obtained with antisera to β-endorphin, cholecystokinin (CCK), neurophysin I and II. Particular neurons could be identified with two antisera (anti-vasopressin/vasotocin, anti-α-MSH/metenkephalin, anti-substance P/PP, anti-PP/gastrin). Apparently this indicates that populations of cells identified with a given antiserum may consist of more than one cell type. Only a few of the new peptidergic cells appeared to be identical with classical neurosecretory cells. Thus the growth hormone producing Light Green Cells stained with anti-somatostatin and the axon terminals of the ovulation hormone producing Caudo-Dorsal Cells with anti-met-enkephalin. Whether this indicates structural identity of the growth hormone with somatostatin and of the ovulation hormone with met-enkephalin remains to be investigated. Just like the classical neurosecretory cells a number of the new peptidergic cells (anti-glucagon, -insulin, -met-enkephalin, -somatostatin, and -PP positive cells) send their axons to the peripheries of commissures, connectives or nerves. Thus these cells can be considered as probably neuroendocrine. The classical neurosecretory cells release their products into the haemolymph from these sites. Other new peptidergic cells (e.g., anti-vasopressin, -vasotocin, -oxytocin and -GIP positive cells) have axons that terminate, probably synaptically, on other neurons, indicating that they are “more conventional” neurons, their products being neurotransmitters/neuromodulators. It can also not be excluded that some cells of a population containing a given peptide are neuroendocrine and others make contact with other neurons.
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    Adrenergic innervation of pancreatic islets and modulation of insulin secretion by the sympatho-adrenal system (1981)
    Springer
    Cell & tissue research 216 (1981), S. 15-30 
    Details
    ISSN: 1432-0878
    Keywords: Pancreatic islets ; Adrenergic innervation ; Insulin secretion ; Chemical sympathectomy ; Adrenalectomy ; Fluorescence histochemistry ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphological changes in the adrenergic innervation of pancreatic islets after chemical sympathectomy by use of 6-hydroxydopamine and the influence of the sympatho-adrenal system on insulin secretion were investigated in the mouse and rat. Fluorescence histochemistry revealed a clear-cut reduction in the number of adrenergic nerve fibers in the pancreatic islets 2 days after administration of 6-hydroxydopamine; the reduction was more pronounced in the rat than in the mouse. In the rat, a partial regeneration was seen after 6 weeks. In the pancreas of the mouse, after administration of 6-hydroxydopamine, a severe damage of unmyelinated nerve fibers was revealed electron microscopically. However, no ultrastructural or immunohistochemical alterations could be demonstrated in the endocrine cells of the islets. 6-Hydroxydopamine induced a depression of basal plasma insulin concentrations in mice and an elevation in rats. Adrenalectomy depressed basal plasma insulin levels in mice. The α-adrenoceptor antagonist phentolamine enhanced insulin secretion in normal mice. The secretory response of insulin to phentolamine was diminished by chemical sympathectomy and almost abolished by adrenalectomy or the combination of chemical sympathectomy and adrenalectomy. Thus, the effect of phentolamine is probably mediated by liberated catecholamines. It is concluded that basal insulin secretion is partially regulated by the sympatho-adrenal system and that species differences exist in this respect. In addition, the results suggest that endogenous catecholamines have the ability to promote insulin secretion.
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    Vasoactive intestinal polypeptide (VIP)-like immunoreactivity in anuran intestine (1981)
    Springer
    Cell & tissue research 216 (1981), S. 413-422 
    Details
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Vasoactive intestinal polypeptide ; Radioimmunoassay ; Gut hormones ; Anura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical and radioimmunological techniques with region specific antisera have been used to identify a vasoactive intestinal polypeptide-like material in the anuran intestine. Seven species of Anura were investigated: Bombina bombina, Alytes obstetricans, Rana temporaria, Rana esculenta, Hyla arborea, Hyla crepitans and Bufo bufo. In five of the species (A. obstetricans, R. temporaria, H. arborea, H. crepitans and B. bufo) vasoactive intestinal polypeptide-like immunoreactive mucosal endocrine cells and nerve fibres in all layers of the gut wall, were detected by both immunofluorescence and peroxidase-antiperoxidase methods. In the other two species, R. esculenta and B. bombina, no mucosal endocrine cells were detected although the vasoactive intestinal polypeptide-immunoreactive nerve fibres were plentiful. Radioimmunoassay showed the presence of significant amounts of vasoactive intestinal polypeptide-immunoreactivity in intestinal extracts from all species. The highest quantities were present in those anurans with both immunostained cells and nerves. Gel permeation chromatography showed that most of the vasoactive intestinal polypeptide-like peptide eluted in a position identical to that of natural mammalian (porcine) vasoactive intestinal polypeptide. The results indicate that a vasoactive intestinal polypeptide-like peptide is well represented in the Anura and that it is immunologically very similar to the mammalian peptide.
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    The isolated perfused rabbit ovary — A model for studies of ovarian function (1981)
    Springer
    Cell & tissue research 216 (1981), S. 471-479 
    Details
    ISSN: 1432-0878
    Keywords: Ovulation ; Perfusion ; Graafian follicle (Rabbit) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present investigation the ultrastructure of isolated rabbit ovaries, perfused with different media for various time periods, was studied. The steroid hormone production by the perfused ovary was also determined. Perfusion with Medium 199 results in prominent interstitial ovarian oedema which increases with perfusion time. Even after the addition of 6–10 % Dextran T40, oedema appears in the interstitial tissue of the ovary. Perfusion solutions with osmotically active colloid particles of large molecular size (Dextran T70; average molecular weight 70,000 and bovine serum albumin), cause less distortion in the ovarian structure, and ultrastructurally the ovarian tissues appear essentially the same as in the control ovaries. The results indicate that the perfused rabbit ovary, under strictly controlled conditions, can be used as an experimental model for studies of various aspects of ovarian function, including follicular rupture.
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    Differentiation of embryonic hypothalamic transplants cultured on the choroidal pia in brains of adult rats (1980)
    Springer
    Cell & tissue research 205 (1980), S. 217-228 
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    ISSN: 1432-0878
    Keywords: Hypothalamus (rat) ; Differentiation ; Transplant ; Histofluorescence ; Immunocytochemistry ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hypothalamic tissue from 16 to 18-day fetal rats was transplanted onto the choroidal pia overlying the superior colliculus in adult female rats. After survival periods of 2 weeks to 19 months, brains containing transplants were processed for monoamine fluorescence histochemistry, immunohistochemistry for three neuropeptides (LHRH, somatostatin, neurophysin), or for autoradiography in ovariectomized hosts that received [3H] estradiol. Most of the transplants survived and retained or increased in size; 14 of 25 transplants examined by fluorescence histochemistry were found to contain median eminence-like structures. In almost all of the transplants that were stained for neuropeptides, beaded processes and occasional cell bodies were observed. Although immunoreactive fibers were found near blood vessels, no palisade arrangement typical of the normal median eminence was evident. Each of the hypothalamic transplants on which steroid autoradiography was performed contained clusters of estrophilic neurons, the intensity of labeling of which was comparable to that seen in the host hypothalamus. These results indicate that many characteristic morphological and chemical features of the hypothalamus, which are not evident in the 16 to 18-day fetus, are elaborated in transplants during the survival period in the host. Transplantation of fetal hypothalamus to adult choroidal pia thus appears to be a valuable approach for studying the factors, humoral or neural, that regulate the differentiation of this brain region.
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    Evidence that lipolytic peptide B occurs in the ACTH/MSH-cells of the pituitary and in the brain (1980)
    Springer
    Cell & tissue research 205 (1980), S. 349-359 
    Details
    ISSN: 1432-0878
    Keywords: Lipolytic peptide B ; Pituitary ; ACTH/MSH cells ; Brain ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Several lipid-mobilizing peptides occur in the pituitary, among them β-lipotropin and “lipolytic peptide A and peptide B”. The latter two peptides are distinct from β-lipotropin and appear to be chemically related to the neurophysins. Immunohistochemistry has now revealed that the lipolytic peptide B of the pituitary is localized in the ACTH- and MSH-cells. In addition, immunoreactive peptide B was found in axons of the posterior lobe of the pituitary. Immunoreactive peptide B was found also in nerve fibers and nerve cell bodies in the hypothalamus, particularly in the hypothalamo-hypophyseal tract and in the magnocellular neuronal system. Immunoreactive nerve fibers were numerous also in the periventricular nucleus of the thalamus. The antiserum against peptide B cross-reacts with neurophysin I, and hence, it cannot be excluded that at least part of the immunostaining in the brain reflects the presence of the latter component. However, the regional distribution of immunoreactive peptide B and neurophysin was not identical. Therefore, it is possible that authentic peptide B occurs not only in the pituitary but also in the brain.
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    Monoaminergic neurons of the mudpuppy retina (1980)
    Springer
    Cell & tissue research 210 (1980), S. 269-282 
    Details
    ISSN: 1432-0878
    Keywords: Monoaminergic neurons ; Retina ; Amacrine cells ; Neurotoxins ; Mudpuppy, Necturus maculosus ; Neurotransmitters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mudpuppy retina was investigated with the histofluorescence method of Falck and Hillarp in normal animals and in animals injected intraocularly with α-methylnoradrenaline, 5,6-dihydroxytryptamine, or a combination of the two drugs. Catecholaminergic amacrine cells were found to form a thin layer of terminals at the border between the inner nuclear and the inner plexiform layers. Catecholaminergic interplexiform cells were not found. Indoleamine-accumulating amacrine cells were also observed. They are fifteen to twenty times more numerous than the catecholaminergic cells, and their terminals occur diffusely throughout the inner plexiform layer. In a number of eyes the majority of the indoleamine-accumulating terminals were eliminated with intraocular injections of the neurotoxin, 5,7-dihydroxytryptamine, but the reproducibility of this effect was not consistent. Intravitreal injections of 5,6-dihydroxytryptamine were used to label both types of neurons for electron microscopy. They were found to make conventional type synapses on amacrine cells and, less frequently, on bipolar cells.
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    Merkel cells and nerve endings in the labial epidermis of a lizard (1980)
    Springer
    Cell & tissue research 210 (1980), S. 353-357 
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    ISSN: 1432-0878
    Keywords: Merkel cells (reptiles) ; Epidermis ; Lizard ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination of the labial epidermis of the lizard Lacerta sicula revealed cells displaying all features of Merkel cells. These cells are located in the stratum basale of epidermal pegs and are arranged in clusters.
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    URL: http://dx.doi.org/10.1007/BF00237623
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    Ultrastructural changes in Paneth cells during hibernation in the ground squirrel Spermophilm lateralis (1980)
    Springer
    Cell & tissue research 211 (1980), S. 293-301 
    Details
    ISSN: 1432-0878
    Keywords: Paneth cell ; Hibernation ; Intestine ; Hypothermia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Paneth cells from jejuno-ileal segments of the small intestine of the ground squirrel, S. lateralis, was examined under normal euthermic conditions and during the profoundly depressed metabolic conditions of natural hibernation. Paneth cells obtained from hibernating animals gave evidence of markedly reduced activity when compared to Paneth cells from euthermic animals. In hibernating animals, the nuclei were smaller, with less prominent nucleoli and with an increased proportion of heterochromatin. In hibernating animals, the rough endoplasmic reticulum was fragmentary and poorly organized, in contrast to the typical arrangement of concentric lamellae seen in euthermic animals. Although the total number of ribosomes was decreased in hibernating animals, there were proportionally more free ribosomes than in euthermic animals. Paneth cells from hibernating animals also contained a greater number of apical secretory granules which were smaller and more variable in electron density than granules from control animals. These ultrastructural features indicate that during hibernation the Paneth cell is relatively quiescent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236450
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  • 95
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    The basement membrane of the insect and crustacean compound eye: Definition, fine structure, and comparative morphology (1981)
    Springer
    Cell & tissue research 216 (1981), S. 205-214 
    Details
    ISSN: 1432-0878
    Keywords: Compound eyes ; Insects ; Crustaceans ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The basement membrane of the compound eye of four insect species and three crustacean species was investigated employing electron microscopy. The basement membrane consists of an extracellular (basal lamina) and a cellular portion, the latter being composed of the flattened terminal extensions of cone cells and accessory pigment cells in insects and distal pigment cells in crustaceans. Other cells can also contribute to the basement membrane. It is thus a complex structure in all well-developed compound eyes. The cellular contributions vary in different species and were found to correlate to specific taxonomic units.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234555
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  • 96
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    Ultrastructural Identification of gastrin-like immunoreactive nerve fibres in the brain of Xenopus laevis by means of colloidal gold or ferritin immunocytochemical methods (1981)
    Springer
    Cell & tissue research 216 (1981), S. 581-589 
    Details
    ISSN: 1432-0878
    Keywords: Gastrin ; CCK ; Median eminence ; Electron microscopy ; Xenopus laevis (Amphibia, Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By use of an anti-gastrin serum and colloidal gold- or ferritin-labelled sheep anti-rabbit γ-globulins, nerve fibres and nerve terminals containing a gastrin-like substance were characterized at the ultrastructural level in the median eminence of Xenopus laevis. These immunoreactive fibres contain neurosecretory granules displaying medium to high electron density and a mean diameter of 75 nm. Labelling intensity varies from granule to granule. This is the first demonstration at the ultrastructural level of the precise location of a gastrin-like hormone in the median eminence of a vertebrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238653
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  • 97
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    Ultrastructure of the pars intermedia of the adult sheep hypophysis (1981)
    Springer
    Cell & tissue research 217 (1981), S. 211-223 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Pars intermedia ; Electron microscopy ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light microscopy of coronal sections of the sheep pars intermedia revealed a compact, incompletely lobulated V-shaped region about 15–20 cells thick, situated between the pars distalis and the pars nervosa. A prominent hypophysial cleft and follicles containing a colloid-like substance were seen. Using electron microscopy, five cell types could be distinguished: pars intermedia glandular cells, pars distalis-like glandular cells, interstitial cells, follicular cells and cleft lining cells. The polyhedral to pear-shaped pars intermedia glandular cells predominated. They contained dense-cored, membrane-bound granules near the Golgi complex, and larger, irregular vesicles with finely granular contents of varying electron density throughout the remaining cytoplasm; exocytotic release of granules was occasionally observed. Smaller numbers of cells resembling those seen in the pars distalis were scattered throughout the pars intermedia. Interstitial cells usually possessed elongated cytoplasmic processes which extended between the glandular cells, and were characterized by deeply indented nuclei, elaborate junctional complexes and an absence of cytoplasmic granules. Cells lining the follicles resembled the interstitial cells. The major cells bordering the hypophysial cleft were triangular in section and bore irregular microvilli on their free surface. The pars intermedia appeared to be less vascular than the remainder of the hypophysis and only occasional fenestrated capillaries were seen. Nerve profiles were rare.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233839
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  • 98
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    Effect of testosterone on the female hamster harderian gland pigmentation and ultrastructure (1980)
    Springer
    Cell & tissue research 207 (1980), S. 511-517 
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    ISSN: 1432-0878
    Keywords: Female hamster ; Harderian gland ; Testosterone ; Tubular clusters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Distinct differences occur in the pigmentation and ultrastructural features of the Harderian glands in male and female hamsters. The results of a study on the effect of testosterone on the fine structure of the female Harderian glands are presented here. Glands from three groups of hamsters were examined at intervals up to 49 days: (1) testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day; (2) sham-injected, receiving 0.1 ml sesame oil per day; (3) untreated controls. Testosterone injections caused a reduction in the number of dark-brown pigment granules in the acinar cells starting on the 6th day, whereas clusters of tubules, typical of adult male glands, appeared on the 4th day and increased in number thereafter. Lamellar structures, normally present in the female gland, decreased in testosterone treated specimens. These changes reversed after cessation of testosterone treatment. It is concluded that exogenous testosterone administered to female hamsters modifies the pigmentation and ultrastructure of their Harderian glands towards the male type and that this is a reversable phenomenon. There also appears to be an inverse relationship between the presence of tubular clusters in the acinar cells, and the degree of pigmentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224624
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  • 99
    Electronic Resource
    Electronic Resource
    Microtubules, dendritic spines and spine apparatuses (1980)
    Springer
    Cell & tissue research 208 (1980), S. 171-181 
    Details
    ISSN: 1432-0878
    Keywords: Microtubules ; Dendritic spine apparatus ; Synapse ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using techniques for enhanced microtubular preservation, including albumin pretreatment (Gray, 1975), occipital cortex of rats was studied electron microscopically at various ages of development. A close structural relationship was seen between microtubules, sacs of SER and the postsynaptic “thickening” in primordial spines and with the dense “plate” material of spine apparatuses. Stereoscopic preparations in addition show a more complicated substructure than previously described for the “plate”. Microtubules may contribute to the formation of the “plate” of the spine apparatus which in turn is associated with the postsynaptic “thickening” of the mature spine. Possible functional correlates are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234868
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  • 100
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    Survival of satellite cells following exposure to the local anesthetic bupivacaine (Marcaine) (1980)
    Springer
    Cell & tissue research 209 (1980), S. 131-135 
    Details
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Bupivacaine ; Degeneration ; Satellite cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat lumbrical muscles were incubated in a concentration of 10-2 M bupivacaine for 5 or 15 min and examined after further incubation in the absence of the drug for periods totalling 1, 2, and 3h. Electron microscopy showed that muscle fibers and their component organelles and myonuclei underwent a series of irreversible degenerative changes. However, satellite cells retained their normal morphology under similar conditions. It is concluded that satellite cells are responsible for the rapid regeneration of muscles that follows degeneration induced by bupivacaine. The role of satellite cells in muscle regeneration is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219929
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