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  • Ultrastructure  (67)
  • pharmacokinetics  (56)
  • Electron microscopy  (48)
  • kinetics
  • man
  • Springer  (181)
  • American Chemical Society
  • 1975-1979  (181)
  • 1979  (181)
Collection
Keywords
Publisher
  • Springer  (181)
  • American Chemical Society
Years
  • 1975-1979  (181)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Studies on the biology of fish bone. III. Ultrastructure of osteogenesis and resorption in osteocytic (cellular) and anosteocytic (acellular) bones (1979)
    Springer
    Calcified tissue international 28 (1979), S. 43-56 
    Details
    ISSN: 1432-0827
    Keywords: Bone resorption ; Osteogenesis ; Fish bone ; Osteocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The comparative ultrastructure of fish bone osteogenesis and resorption induced by scale removal was described in the osteocytic (cellular-boned)Carassius auratus and the anosteocytic (acellular-boned)Tilapia macrocephala. Osteocytes, present in osteocytic bone, were lacking in anosteocytic bone. In osteocytic bone the osteoblast secreted a collagenous preosseous matrix in which it became enmeshed and then was termed a preosteocyte. When the preosseous matrix mineralized, the preosteocyte was termed an osteocyte and was completely surrounded by bone. In anosteocytic bone the osteoblasts receded from the mineralizing front and never became trapped as osteocytes. During resorption, types A and B resorptive cells, present in both bone types, invaded the matrix and demineralized the osseous zone. These cells were characterized by large amounts of granular endoplasmic reticulum and intracellular inclusions containing crystal-like material. Although functionally similar to mammalian osteoclasts, these cells lacked a characteristic ruffled border and were not multinucleated. The osteocytes of cellular bone did not appear to be involved during demineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441217
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  • 2
    Electronic Resource
    Electronic Resource
    Time-related changes in the ultrastructure of osteoclasts after injection of parathyroid hormone in young rats (1979)
    Springer
    Calcified tissue international 27 (1979), S. 129-135 
    Details
    ISSN: 1432-0827
    Keywords: Parathyroid hormone ; Osteoclasts ; Electron microscopy ; Morphometry ; Metaphysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effects of parathyroid hormone (PTH) on the size of the osteoclasts, nuclei, ruffled borders, and clear zones in long bones of thyroparathyroidectomized (TPTX) rats were quantitated as a function of time. These data were compared with the number of osteoclasts in the bone and with plasma calcium levels. A significant increase in the average size of the ruffled borders was demonstrated 30 min after injection of 50 U of purified bovine PTH, and of the clear zones 30–90 min after PTH. This was followed at 90 min by an increase in the average size of the cells. The sizes of ruffled borders and clear zones dropped sharply to control levels after 6 h, whereas the size of the cells remained elevated up to 12 h and returned to control values at 24 h. Plasma calcium levels were increased, but not significantly, between 30 min and 6 h. An increase in the number of osteoclasts was significant after 12 h. Removal of the parathyroid glands did not diminish the normal activity of osteoclasts. In animals with intact glands injection of 50 U of PTH did not cause a significant change in cell size or resorbing apparatus. It is concluded that PTH acts to rapidly stimulate the bone resorptive activity of osteoclasts and to cause a delayed increase in their number.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441175
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructure of collagen in sea urchin embryos (1979)
    Springer
    Development genes and evolution 186 (1979), S. 65-70 
    Details
    ISSN: 1432-041X
    Keywords: Sea urchin ; Embryo ; Collagen ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Collagen fibrils with a main period banding of 610 Å and 220 Å in width were observed in the blastocoel of 72-h embryos of the sea urchin,Strongylocentrotus purpuratus. Non-striated fibrils of 50 Å diameter were also observed. The collagen is seen in highest concentration in the vicinity of mesenchyme cells which are richly endowed with endoplasmic reticulum and secretory vesicles. A role for collagen in cell attachment, orientation and spicule formation is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848108
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  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in the distal wing bud of the chick embryo after removal of the apical ectodermal ridge (1979)
    Springer
    Development genes and evolution 185 (1979), S. 333-346 
    Details
    ISSN: 1432-041X
    Keywords: Chick embryo ; Limb bud ; Ultrastructure ; Cell death
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural changes in the wing bud afterapical ectodermal ridge (A.E.R.) removal was studied to re-examine the issue of distal mesenchymal cell death. The A.E.R. of the right wing bud was removed microsurgically from chick embryos of stages 18 to 22 (HH 1951). The wing buds were examined at three hour intervals up to twelve hours after the operation with light, transmission and scanning electron microscopy. The main findings were: (1) Immediate and temporary shrinkage of the mesenchymal extracellular space 100 to 150 μm and chromatin condensation in the cells 50 to 75 μm from the wound. (2) Death of ectodermal and mesenchymal cells in the immediate vicinity of the wound. (3) Formation of a single squamous-like layer of mesenchymal cells to cover the wound. (4) Occasional evidence of cell death in the distal mesenchyme at later times after the operation. The pattern of cell death observed suggests only a traumatic etiology, and gives little evidence for the postulated developmental significance of cell death following A.E.R. removal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848520
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  • 5
    Electronic Resource
    Electronic Resource
    Orientation of apatite in single osteon samples as studied by pole figures (1979)
    Springer
    Calcified tissue international 29 (1979), S. 101-105 
    Details
    ISSN: 1432-0827
    Keywords: Osteon ; X-ray diffraction ; Pole figures ; Electron microscopy ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The X-ray diffraction method based on pole figures has been applied to single osteon samples in order to obtain information about the texture of the inorganic bone fraction and the way it changes during calcification. The osteon samples were cylindrically shaped, with axes corresponding to those of the haversian canals. Selection was carried out according to the degree of calcification and the orientation of collagen bundles and inorganic particles. Osteons at both the initial and final stages of calcification were chosen. Arrangements of fiber bundles and inorganic particles in successive lamellae characteristic of three types of osteons were selected: longitudinal, alternate, and transversal. The results indicate that in all three types of osteons, the long axis of the sample is apparently the only direction of orientation because the transversally oriented crystallites give an isotropic diffuse scattering as would be expected if all the inorganic particles were irregularly oriented around the osteon axis. The number of longitudinally oriented crystallites increases progressively from transversally oriented osteons to alternately and longitudinally oriented ones. The crystallite orientation in an axial direction increases in fully calcified osteons. This last result is in agreement with the electron microscopic finding that the long needle-shaped crystallites covering much more than a major collagen period and measuring 40–45 Å in width increase in number as calcification proceeds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408064
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  • 6
    Electronic Resource
    Electronic Resource
    Relationship between plasma concentration and effect of dantrolene sodium in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 203-209 
    Details
    ISSN: 1432-1041
    Keywords: dantrolene sodium ; spasticity ; twitch tension ; dose response ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Dantrolen sodium is a muscle relaxant, which is used in the treatment of spasticity. Although it is given chronically, little is known about its pharmacokinetic behaviour. The relationship between the effect of a single oral dose of dantrolene sodium and its plasma concentration in healthy volunteers was studied by measuring the effect on the twitch tension, and in spastic patients on the decrease in muscle hypertonia. On the twitch tension dantrolene gave a depression of 49.1±9.4% (±SD) within 1.15 and 3.45 h after ingestion of 100 mg. The mean maximal plasma concentration was 1.24±0.32 µg/ml (±SD). The effect and the plasma concentration were correlated. No relationship between the plasma concentration of dantrolene sodium and its effect could be established in patients, although definite activity in 6 out of 7 patients was observed after a single oral dose of 100 mg, and plasma concentration of dantrolene sodium greater than 0.3 µg/ml were consistently associated with better results than placebo treatment in 6 out of 7 patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562062
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  • 7
    Electronic Resource
    Electronic Resource
    Pharmacokinetic model based on circulatory transport (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 287-293 
    Details
    ISSN: 1432-1041
    Keywords: linear system theory ; perfusion model ; cardiac output ; pulmonary extraction ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Assessment of pharmacokinetics in terms of circulatory drug transport is proposed using the methods of linear system theory. In this model-independent approach drug distribution and disposition are characterized by the total extraction ratio, the mean residence time in the body and the volume of distribution at steady state. In analyzing concentration(c)-time(t) data, the procedure requires calculation only of the areas under the c(t)-and c(t)×t-curves to estimate kinetic parameters, and for prediction of the steady state concentration following continuous infusion or multiple doses. Pulmonary clearance of drugs is included in the theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608408
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  • 8
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of bromocriptine during continuous oral treatment of Parkinson's disease (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 275-280 
    Details
    ISSN: 1432-1041
    Keywords: Parkinson's disease ; bromocriptine ; pharmacokinetics ; plasma concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma kinetics of bromocriptine (BCT), a long-acting dopamine agonist, was studied in twelve patients with Parkinson's disease, using a newly developed gas chromatographic method of analysis. Each patient received BCT for at least three weeks in a constant but different dose regimen. Concomitant treatment with 1-DOPA was not allowed. During a 6-day hospitalization period, a blood sample was taken immediately before the afternoon dose at 14.00 h (Cmin) to determine the steady-state level. On the 6th day blood samples were collected every hour during two 8 h dose intervals. The results showed a significant correlation between the mean values of the AUC and the Cmin. First order elimination kinetics appeared to be followed by BCT, at least for the plasma concentrations commonly found. Considerable inter-individual variation was demonstrated both for the dose/plasma concentration ratio and for calculated plasma clearances. No serious side-effects were observed during the investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00618517
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  • 9
    Electronic Resource
    Electronic Resource
    Indobufen (K 3920), a new inhibitor of platelet aggregation: Effect of food on bioavailability, pharmacokinetic and pharmacodynamic study during repeated oral administration to man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 329-333 
    Details
    ISSN: 1432-1041
    Keywords: indobufen ; platelet aggregation ; food effect on bioavailability ; repeated administration ; pharmacodynamics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of food on bioavailability of indobufen tablets was investigated in 6 healthy volunteers. Subsequently, the same subjects took 100 mg b.i.d. for 7 days. Plasma levels and urinary excretion of indobufen were determined by GLC. Platelet aggregation induced by several concentrations of adrenaline was determined turbidimetrically at various times after the first and last doses. The absorption of indobufen tablets was not substantially impaired by the presence of food in the GI tract, although peak plasma levels and AUCs were slightly reduced after food. Pharmacokinetic analysis of plasma and urinary levels of indobufen did not indicate any change in drug disposition after repeated dosing. Adrenaline-induced platelet aggregation was markedly inhibited for up to 12 h after the first dose and the intensity and duration of this effect did not change after repeated administration. A twice-daily dosing appears suitable for clinical trials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558436
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  • 10
    Electronic Resource
    Electronic Resource
    Clofibrate disposition in renal failure and acute and chronic liver disease (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 341-347 
    Details
    ISSN: 1432-1041
    Keywords: clofibrate ; chlorophenoxyisobutyric acid ; disposition ; hepatitis ; cirrhosis ; renal failure ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition of clofibrate over 96 hours was observed following single oral dose in six patients with acute viral hepatitis, six patients with liver cirrhosis, seven patients with renal insufficiency, and six control subjects. No parameter of the disposition of CPIB (active form of clofibrate) was significantly altered in acute hepatitis. In liver cirrhosis, the mean plasma half-life was unchanged compared to controls (20.9 vs. 17.5 h), but plasma clearance of the non-protein bound drug was reduced (115 vs. 243 ml×min−1), plasma protein binding was reduced (92.8 vs. 97.2 percent), and the apparent volume of distribution was increased (0.20 vs. 0.141×kg−1). In renal insufficiency plasma half-life was prolonged 2 to 6-fold, depending on the degree of renal impairment. Total plasma clearance (3.4 vs. 7.1 ml×min−1) and plasma clearance of the unbound drug (81 vs. 243 ml×min−1 were reduced in patients with renal failure, the clearance of the unbound drug being inversely correlated with the serum creatinine concentration. Renal failure was also associated with decreased protein binding and an increased volume of distribution of CPIB, and with reduced urinary excretion of CPIB and its glucuronide metabolite. The dose of clofibrate should be halved in patients with cirrhosis. In renal insufficiency, the dose should be adjusted according to the individual serum creatinine level: only 10 to 15% of the usual weekly dose should be given in complete renal failure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558438
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  • 11
    Electronic Resource
    Electronic Resource
    The protein binding of methotrexate by the serum of normal subjects (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 363-366 
    Details
    ISSN: 1432-1041
    Keywords: methotrexate ; protein binding ; ultrafiltration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The protein binding of methotrexate by serum from eight normal volunteers was assessed by continuous ultrafiltration at pH 7.4 and 37°C. Methotrexate concentrations were measured by radioimmunoassay and the data analysed by the method of Scatchard. The major binding protein was albumin which bound 87.3% of the drug in serum. Analysis of the Scatchard plots indicated two distinct groups of binding sites. Class I was found to have 0.16±0.05 (S D) binding sites with an intrinsic association constant of 71.15±35.98 (S D)×104 M−1: Class II had 2.01±0.93 (S D) binding sites and an affinity of 0.18±0.15×104 M−1. No great change in the percentage of methotrexate bound occurred until the total concentration of the drug exceeded 50 µMol 1−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558441
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  • 12
    Electronic Resource
    Electronic Resource
    Improved oral glucose tolerance following antiserotonin treatment in patients with chemical diabetes (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 395-399 
    Details
    ISSN: 1432-1041
    Keywords: cyproheptadine ; metergoline ; glucose tolerance ; insulin secretion ; chemical diabetes ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of short-term treatment with either placebo or two serotonin antagonists, cyproheptadine and metergoline, on oral glucose tolerance and insulin secretion have been evaluated in normal subjects and in patients with chemical diabetes. Placebo treatment was not associated with any significant change in the parameters examined. Glucose tolerance in chemical diabetics was significantly improved both after cyproheptadine and metergoline; fasting plasma glucose was also reduced by metergoline. Treatment with the latter drug was also associated with a significant decrease in incremental glucose area in healthy subjects, which was not affected by cyproheptadine. Basal and glucose-stimulated insulin secretion were not affected by either drug in any subjects. Cyproheptadine and metergoline improve glucose metabolism in chemical diabetes probably by reducing insulin resistance. This may depend either on decreased secretion of counter-regulatory hormones or on a direct pharmacological action of the drugs on glucose utilization, possibly mediated by their common antiserotoninergic properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561737
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  • 13
    Electronic Resource
    Electronic Resource
    Timolol pharmacokinetics and effects on heart rate and blood pressure after acute and chronic administration (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 243-249 
    Details
    ISSN: 1432-1041
    Keywords: timolol ; beta blockade ; pharmacokinetics ; pharmcodynamics ; acute administration ; chronic administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and effects of various oral doses of timolol administered either acutely or after chronic medication for 7 days were studied in healthy volunteers. After acute administration of timolol maximum plasma concentrations were attained within 1–2 h and thereafter declined exponentially with time. The mean apparent half-life of elimination from plasma was 2.5 h and was independent of dose. Area under the plasma concentration-time curve (AUC) was proportional to the orally administered dose. Plasma concentrations, apparent elimination half-life and AUC were not altered after one week of chronic administration. The effect of timolol on heart rate and blood pressure response to three sequentially increasing ‘steady state’ work loads were studied. After acute administration of timolol maximum reduction of systolic blood pressure, resting heart rate, and the different parameters of the work-heart rate (or blood pressure) relationships were produced by 5 mg timolol. Increasing the dose prolonged the duration over which these variables were reduced. The relationship between timolol plasma concentration and inhibition of different parameters of the exercise response was hyperbolic with half maximum inhibition at concentrations of about 3–4 ng/ml of timolol and maximum inhibition above 30 ng/ml. Maximum drug effects and duration of action of timolol on the different variables were similar after acute and chronic administration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608402
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  • 14
    Electronic Resource
    Electronic Resource
    Pharmacokinetic and pharmacodynamic interactions of diazepam with different alcoholic beverages (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 263-270 
    Details
    ISSN: 1432-1041
    Keywords: diazepam ; alcoholic beverages ; plasma level ; pharmacokinetics ; co-ordination skills ; red wine ; white wine ; whisky
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Twenty paid healthy students ingested diazepam 10 mg 30 min after the administration of ethanol 0.8 g/kg. The alcoholic beverage used was varied in randomized double-blind experiments, which were repeated at one-month intervals. Psychomotor performance, plasma diazepam, and alcohol concentration in breath were measured 30, 60, 90 min and 2, 3, 4, 6 and 24 h after the ingestion of diazepam. Beer and white wine elevated the plasma level of diazepam and the effect lasted for up to 2 h. Whisky elevated the diazepam level for 90 min. Red wine did not affect it significantly. The alcohol-diazepam combination impaired tracking skills and oculomotor co-ordination and enhanced nystagmus, more than diazepam alone. Red wine produced a breath alcohol concentration higher than after white wine. More nystagmus was recorded after red wine and diazepam, although white wine led to a higher plasma diazepam concentration. It appears that simultaneous ingestion of alcohol and diazepam accelerates the absorption of diazepam. This pharmacokinetic alteration may not contribute much to the combined psychomotor effects of diazepam and alcohol, which were mainly due to pharmacodynamic interaction at receptor level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608405
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  • 15
    Electronic Resource
    Electronic Resource
    Analysis of the pharmacokinetics of lithium in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 271-277 
    Details
    ISSN: 1432-1041
    Keywords: lithium ; litarex ; single dose ; multiple dose ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary An analysis of the single and multiple dose pharmacokinetics of lithium in 7 healthy volunteers is presented. A solution of lithium chloride was administered in single dose experiments and the same solution and a sustained release preparation were employed in multiple dose experiments, which were carried out at steady state. A fixed dose of 24 mmol was used in the single dose experiments and in the subsequent multiple dose experiments in the same subjects the same dose was administered once daily for a week. Distinct two-compartment characteristics were found, with a mean disposition rate constant (β) of 0.035 h−1±0.010 SD, corresponding to a mean biological half-life of about 19.8 h. The mean half-time of the distributory α-phase was about 1.15 h. The absorption of lithium from an orally administered solution took place with a half-time of about 0.15 h in the single dose experiments. The apparent volume of distribution of the central compartment (Vc) was 0.307 1 kg−1±0.046 SD, less than half that of Vde at equilibrium. Vdβ (Vdarea) was 0.8291 kg−1±0.184 SD and mean total body clearance was 27.6 ml kg−1 h−1±4.7 SD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608406
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  • 16
    Electronic Resource
    Electronic Resource
    Kinetics of canrenone after single and multiple doses of spironolactone (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 255-262 
    Details
    ISSN: 1432-1041
    Keywords: spironolactone ; canrenone ; fluorimetry ; high performance liquid chromatography ; linear kinetics ; saturation kinetics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In Study I 20 normal volunteers received a single oral dose of spironolactone 100 mg. In Study II a further 20 normal volunteers were given first spironolactone 100 mg b.i.d. and subsequently spironolactone 100 mg once a day for a further 4 days. In Study III 5 normal subjects were given a single dose of spironolactone 500 mg. The concentration of canrenone in serum was determined both by fluorimetry and HPLC for 0–48 h in Study I, 120–168 h in Study II and 0–36 h in Study III. The total AUCs after the single 100 mg dose did not differ from the AUCs within the dosing interval during steady state. The half-lives of the terminal log-linear phases were almost identical (14.99±0.80 h and 15.69±0,80 h) when determined by fluorimetry, and were sligthly, but significantly (p〈0.01), longer when determined by HPLC — 20.14±1.62 and 18.71±1.04. The mean ratio of the specific AUC determined by HPLC and the fluorimetrically determined AUC was 0.3 after the single 100 mg dose. It did not differ from the corresponding value during steady state (0.34). In contrast, the ratio after the single 500 mg dose was approximately 50% higher. Fluorimetrically determined AUCs after 100 and 500 mg doses did not show dose-proportionality in contrast to the HPLC-determined AUCs. It was concluded that Canrenone contributes much less to the conventional fluorimetric determination than was previously assumed. It may not provide more than 1/10 and 1/4 of the antimineralocorticoid activity of spironolactone after single dose and multiple doses, respectively. Whereas linear kinetics apply after single and multiple 100 mg doses of spironolactone, after 500 mg saturation kinetics must be assumed with respect to metabolism. Thus, in bioavailability studies high doses of spironolactone should be avoided. For such studies the fluorimetric assay seems to be the appropriate bioanalytical method in spite of its lower specificity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00608404
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  • 17
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of quinidine related to plasma protein binding in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 187-192 
    Details
    ISSN: 1432-1041
    Keywords: quinidine ; plasma protein binding ; pharmacokinetics ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition and plasma protein binding of quinidine after intravenous administration were studied in 13 healthy subjects. Plasma protein binding, expressed as the fraction of quinidine unbound ranged from 0.134–0.303 (mean 0.221). Elimination rate constant (β) varied from 0.071 to 0.146 h−1 (mean 0.113), and apparent volume of distribution (Vβ) varied from 1.39–3.20 l · kg−1β (mean 2.27). Total body clearance was 2.32–6.49 ml min−1 · kg−1. There was a positive linear correlation between the plasma fraction of unbound quinidine and both Vβ (r=0.885, p〈0.01) and total body clearance (r=0.668, p〈0.05). No significant correlation existed between the fraction of unbound quinidine in plasma and the elimination rate constant. The results show that both the apparent volume of distribution and total body clearance of quinidine are proportional to the unbound fraction in plasma. This implies that the total plasma concentration of quinidine at steady state will change with alterations in plasma binding, whilst the concentration of unbound compund and its elimination rate will remain unaffected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00563104
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  • 18
    Electronic Resource
    Electronic Resource
    Oral absorption of cimetidine and its clearance in patients with renal failure (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 153-157 
    Details
    ISSN: 1432-1041
    Keywords: cimetidine ; renal failure ; elimination half life ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma concentration curve after a single oral dose of cimetidine 200 mg was followed in 27 patients with varying degrees of chronic renal failure (creatinine clearance 1–52 ml/min) and in 46 patients with normal serum creatinine. Compared to the latter patients, the plasma concentration was higher and the elimination rate was slower in all uraemic subjects, including a group with moderate renal impairment. The preliminary recommendations of dosage for patients with a creatinine clearance below 5 ml/min, and for patients on regular haemodialysis, is cimetidine 200 mg every 12 h, 5–15 ml/min 200 mg every 12 to 8 h, 15–30 ml/min 200 mg every 8 h and 30–52 ml/min 200 mg every 6 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00563098
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  • 19
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    Human pharmacokinetics of nitrazepam: Effect of age and diseases (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 163-170 
    Details
    ISSN: 1432-1041
    Keywords: nitrazepam ; epilepsy ; age ; disease ; plasma concentration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma concentrations of nitrazepam were measured by gas-liquid chromatography in: young healthy volunteers, in geriatric and psychiatric patients and in epileptic children. The disposition of nitrazepam was described in terms of a two-compartment open model. After a single oral dose of nitrazepam 5 mg the most prominent differences between the experimental groups were in the β-phase half-life-mean 29 h in the young volunteers and 40 h in geriatric patients, and in the apparent volume of distribution during the β-phase of 2.4 vs 4.8 l/kg. Total plasma clearance and the average steady state concentration in both groups were equal. The plasma level rose at a rate proportional to the β-phase half-life, and so, they were achieved more rapidly in the young than in the old subjects (3.5 vs 7.5 d). No change in steady-state level or in the half-life of nitrazepam were found during long term treatment, which indicates lack of enzyme induction or inhibition. In 95% of the epileptic children with a good to fair clinical response, the plasma concentration of nitrazepam was 40–180 ng/ml (mean 114 ng/ml). As all of the patients were on combined antiepileptic therapy, no attempt was made to correlate plasma level with therapeutic response.
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    Pharmacokinetics of clorazepate in pregnant and non-pregnant women (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 175-180 
    Details
    ISSN: 1432-1041
    Keywords: clorazepate ; nordiazepam ; pregnancy ; pharmacokinetics ; intramuscular injection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A single dose of clorazepate 20 mg was injected i.m. in 7 pregnant and 7 non-pregnant women. Blood samples were collected for one week, and urine was collected for 24 h after the dose. The concentrations of clorazepate and its metabolite nordiazepam were determined by electron capture gas liquid chromatography. There was no difference between the two groups on physical examinations. Clorazepate was rapidly absorbed and the peak concentration was reached within 2h. Mean pharmacokinetic parameters for clorazepate were absorption half life 0.77h in pregnant women and 0.56h in non-pregnant women; elimination half life 1.3h in pregnant women and 2.0h in non-pregnant women; volume of distribution: 0.43 l · kg−1 in the pregnant women and 0.33 l · kg−1 in non-pregnant women. Nordiazepam reached its peak concentration within 12h after dosing; its mean half life of elimination was 180h in pregnant women and 60h in non-pregnant women. Within 24h, 1.3% of the clorazepate was recovered in urine from pregnant women and 7% in urine from the non-pregnant women.
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    Blood level of cimetidine in relation to age (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 257-261 
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    ISSN: 1432-1041
    Keywords: cimetidine ; H2-receptor antagonist ; aging ; single dose ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The blood level versus time curve for unchanged cimetidine after a 200 mg oral dose has been determined in 20 apparently healthy subjects, ranging from 22 to 84 years of age. A significant relationship between the area under the curve (AUC) and age was found (r=0.81; P〈0.001). The peak concentrations of cimetidine were significantly inversely related to body weight (r=−0.71; P〈0.001). The age-related increase in bioavailability of oral cimetidine, as measured by AUC, was probably due to decreased total clearance of the drug, which resulted from the opposed changes (by themselves not significant) of distribution volume towards a decrease and of half-life towards an increase with age. Reduction in the standard oral dose of cimetidine by one third to one half should be feasible in the elderly without loss of efficacy, and it may be advisable in order to obviate extreme individual responses that may occur in this population.
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    URL: http://dx.doi.org/10.1007/BF00618514
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    Absolute bioavailability of chlorthalidone in man: A cross-over study after intravenous and oral administration (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 35-50 
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    ISSN: 1432-1041
    Keywords: chlorthalidone ; pharmacokinetics ; oral and i.v. doses ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Seven normal human volunteers each received a constant-rate infusion of chlorthalidone for 2 h, and the same (commonly 50 mg) single oral dose on separate occasions. The concentration of unchanged chlorthalidone was analyzed over a 100 to 220 h period in plasma, red blood cells, urine and faeces after both dosage forms. A three compartment model was required to describe the intravenous plasma concentrations in five of the subjects. A two compartment model sufficed to account for the decay of the oral plasma concentrations in all seven subjects. The mean plasma t1/2 after i.v. dosing was 36.5 h (±10.5 SD), and the mean plasma t1/2 after oral doses was 44.1 h (±9.6 SD). The mean red blood cell concentration t1/2 after i.v. doses was 46.4 h (±9.9 SD), and the mean red blood cell t1/2 after the oral doses was 52.7 h (±9.0 SD). The shorter i.v. half-live was not equally manifest in all subjects, being mainly apparent in three of them. In all cases the urinary excretion rate plots were parallel to the plasma concentration curves. As the faster decay after i.v. administration was not accompanied by increased renal clearance, the difference must have been due to non-renal mechanism. The mean total of 65.4 (±8.6 SD) % of the intravenous dose was excreted in urine over infinite time, whereas the mean total excretion after the oral dose was 43.8 (±8.5 SD) %. Faecal excretion ranged from 1.3–8.5% of dose in the i.v. study to 17.5–31.2% of dose in the oral study. The sum of the amounts present in urine plus faeces pointed strongly to an important metabolic route of elimination of chlorthalidone. Bioavailability estimates (F) from three sets of data were — a mean F of 0.61 from plasma concentrations, 0.67 from urinary excretion measurements and 0.72 from the erythrocyte concentrations. Simulations with a non-linear model indicated lesser validity of the estimate from erythrocyte concentrations. It was concluded that the average of plasma and urine data, F=0.64, yielded the best estimate of the oral availability of chlorthalidone 50 mg in man.
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    Use of a simulation model to study the acute haemodynamic effects of diazoxide in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 73-81 
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    ISSN: 1432-1041
    Keywords: simulation model ; diazoxide hypotension ; haemodynamics ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The acute haemodynamic effects of injected diazoxide (Hyperstat® Schering) have been studied in 8 hypertensive subjects. Aortic blood pressure was measured and cardiac output and peripheral conductance were assessed continuously using a simulation model. In six of the patients pulmonary artery end-diastolic pressure was also measured. Blood pressure fell in all subjects 5–10 min after injection of the drug cardiac output increased in all patients studied. However, the initial change in cardiac output differed, as it decreased in two subjects and did not change in one. The largest initial increases in cardiac output were seen in the subjects with the highest pulmonary artery end-diastolic pressure. Patients with an initial decrease in cardiac output were those with the least compliant (stiffest) aortas. We consider that the responsiveness of the baroreceptors determines the size of the increase in cardiac output immediately after reduction of blood pressure by diazoxide. Thus in a patient with a stiff aorta, particularly at low cardiac filling pressure, diazoxide might cause a fall in blood pressure to an unacceptable level.
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    Disposition of guanethidine during chronic oral therapy (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 121-125 
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    ISSN: 1432-1041
    Keywords: guanethidine ; chronic therapy ; urinary excretion ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma level and urinary excretion rate of guanethidine have been measured in 30 patients during oral maintenance therapy, and in 5 patients following discontinuation of therapy. A significant correlation was found between the daily average urinary excretion and the maintenance dose, although wide interindividual variation was noted among patients maintained on the same dose. A statistically significant correlation was also observed between the area under the plasma level curve during the dose interval and the oral maintenance dose. After discontinuation of chronic therapy, the half-life of 1.5 days of the initial phase of elimination was essentially in agreement with the half-life of almost 2 days determined in acute studies. In addition, a second phase of elimination with a half-life of 4 to 8 days was observed.
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    Pharmacokinetics of the placental transfer and distribution of clorazepate and its metabolite nordiazepam in the feto-placental unit and in the neonate (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 181-185 
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    ISSN: 1432-1041
    Keywords: clorazepate ; nordiazepam ; pregnancy ; placental transfer ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Clorazepate 20mg was given i. m. to 49 mothers during the first stage of labour. The elimination of the drug was studied in 27 newborns produced by these mothers. The same dose was given to 13 women who underwent amniocentesis and to 7 women who were breast-feeding. “Total nordiazepam”, i.e. the sum of clorazepate and its metabolite nordiazepam, was determined by gas-liquid chromatography in maternal blood, umbilical cord blood (both arterial and venous), amniotic fluid and in milk. Clorazepate was found to cross the placental barrier slowly, but nordiazepam was transferred more rapidly. Nordiazepam was found in the milk and in the blood of neonates after breast-feeding had started.
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    Disposition pharmacokinetics of bezafibrate in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 31-38 
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    ISSN: 1432-1041
    Keywords: bezafibrate ; hyperlipoproteinemia ; bioavailability ; pharmacokinetics ; GC-MS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disposition kinetics of bezafibrate, a newly developed drug of great lipid-lowering potency, were investigated in normal male subjects. Five male volunteers received14C-labelled bezafibrate orally in solution, and a further 10 were given the same dose (300 mg) of un-labelled drug as tablets. The concentration of bezafibrate in serum and urine from the latter was determined by GC, and in the former total radioactivity in serum, urine and feces was followed for 48 h, and urinary excretion products were analysed by TLC and GC-MS. Rapid absorption from the gastrointestinal tract led to peak serum levels 30 min and 2 h after administration of solution and tablets, respectively. Since approximately 95% of the administered14C-bezafibrate was excreted in urine within 48 h, and almost all the remainder was detected in feces, absorption can be regarded as complete after administration in solution. The relative optimal bioavailability from the tablets was also complete, since in both cases approximately 50% of the administered dose was detected as unchanged bezafibrate in urine within 24 h by GC in the tablet study, and by TLC in the solution study. Of the decomposition products, more than 20% of the dose was present as glucuronides and the remainder consisted of several more polar compounds, one of which was identified as a hydroxyderivative of bezafibrate. Since the apparent halflife of bezafibrate in serum was 2.1 h, this new drug possesses favourable pharmacokinetic features: rapid and complete absorption, even from tablets, combined with a conveniently short half-life, and clearance which is half renal (56 ml/min) and half metabolic (43 ml/min), giving a total clearance of 99 ml/min.
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    Pharmacokinetic, bioavailability and pharmacodynamic study of indobufen (K 3920), an inhibitor of platelet aggregation, after a single dose in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 323-327 
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    ISSN: 1432-1041
    Keywords: indobufen ; platelet aggregation ; single dose ; bioavailability ; pharmacodynamics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Six healthy volunteers received single iv and oral doses of 2-[p-(1-oxo-2-isoindolinyl)phenyl] butyric acid 100 mg (indobufen; K 3920), an inhibitor of platelet aggregation. Plasma levels and urinary excretion of the drug were determined by GLC. Collagen-induced platelet aggregation was assessed turbidimetrically at various intervals after administration. The plasma half-life of the drug was 7–8 h and more than 70% of the administered dose was recovered within 48 h in urine, as unchanged drug and as the glucuronide of indobufen. After oral administration of tablets of two different formulations, the drug was completely absorbed, but one formulation showed faster absorption. The maximal inhibitory effect on platelet aggregation was observed 1 to 4 h after iv administration, and it had decreased by 8 h. After tablets, peak effect and the time of the peak were similar, but activity was significantly prolonged, in accordance with the higher plasma levels found at 8 h. The data suggest that the effect of indobufen on platelets is reversible, and that for this drug platelets behave as a compartment that slowly equilibrates with plasma.
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    Cyclobarbital as a test substance for oxidative drug metabolism in man. Findings in neuropsychiatric patients (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 433-441 
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    ISSN: 1432-1041
    Keywords: cyclobarbital ; barbiturates ; pharmacokinetics ; drug interaction ; volunteers ; patients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The disappearance of cyclobarbital from plasma has been followed in healthy volunteers and in neurological and psychiatric patients after oral administration of one tablet of Phanodorm®, containing cyclobarbital calcium 200 mg. Plasma levels were measured by a thin-layer chromatographic method with in situ densitometry. The average t1/2 in healthy female and male volunteers was 13.3 h, and with the assumption of complete availability a mean distribution coefficient of 0.69 l/kg−1 and a clearance of 40.4 ml/min−1 were calculated. Repeated experiments in seven volunteers revealed good reproducibility of all values. When the healthy volunteers were combined with a group of untreated epileptics, a dependence of t1/2 and of the apparent volume of distribution on age was found, while clearance did not change with increasing age (range 17–54 years). Long half-lives caused by low clearance values were observed in several individuals with moderate obesity. No consistent change in cyclobarbital kinetics followed acute exposure of volunteers to alcohol or on treatment of neurological patients with carbamazepine. Patients under treatment with perazine exhibited more or less normal kinetic values. In terms of drug interaction, cyclobarbital differs from phenazone in several respects, and so it may prove a useful additional substance for measurement of the rate of drug oxidation in humans.
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    Lorcainide infusion in the treatment of ventricular premature beats (VPB) (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 1-6 
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    ISSN: 1432-1041
    Keywords: lorcainide ; ventricular premature beats ; plasma levels ; pharmacokinetics ; side effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma level and antiarrhythmic effect of lorcainide (R 15889) have been investigated in 15 patients with ventricular premature beats (VPB). Therapy was initiated with an intravenous dose of 1.9 mg/kg given over 10 min, followed by a constant infusion of 0.18 mg/kg/h for 24 h. In 8 patients the corresponding doses were increased to 2 mg/kg and 0.27 mg/kg/h. After the intravenous doses patients were treated orally with 100 mg tid for 6–7 days. The two dosage regimens were selected so as to achieve theoretical steady-state plasma levels (css) of 200 and 300 ng/ml, respectively. The combined intravenous treatment approached (181 ± 6.8 ng/ml and 273±28.5 ng/ml, respectively) the desired css within 2 to 4 h. During the oral administration, the minimal plasma concentrations following the lower intravenous dose (184±18 ng/ml) were significantly (p=0.0001) lower than after the higher intravenous dose (264±20.5 ng/ml). The dealkylated metabolite of lorcainide was not detectable after the intravenous doses, but it accumulated during oral treatment, when its concentration exceeded that of the parent compound. In 5 of the 7 patients receiving the lower dose VPB were effectively reduced. However, in only 4 of the 8 patients on the higher dosage schedule could a significant antiarrhythmic effect be demonstrated. In addition, side effects were observed in 6 of the subjects.
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    Single and chronic dose pharmacokinetic studies of sodium valproate in epileptic patients (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 23-29 
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    ISSN: 1432-1041
    Keywords: valproate ; epilepsy ; pharmacokinetics ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In four refractory epileptic patients, peak plasma levels of sodium valproate occurred within 1.5 to 3 h after a single oral dose of valproate and the decline in plasma levels followed a monoexponential course with a t1/2 of 11.4 ± 0.1 h. The mean value for apparent volume of distribution was 0.176 ± 0.013 l/kg and for total plasma clearance 0.0106 ± 0.0009 l/h/kg. Steady state plasma levels were predicted using the method of superposition utilizing pharmacokinetic parameters determined following a single dose of valproate and were 78–123% of the predicted values for two patients receiving valproate alone, and 37–64% of the predicted values for the two patients receiving carbamazepine in addition to valproate. In a further group of 20 patients the mean daily doses of valproate for 8 patients receiving valproate alone (25.4 ± 4.9 mg/kg) was significantly less than those for the 12 patients receiving concomitant anticonvulsant therapy (41.6 ± 12.3 mg/kg) (p〈0.005). In addition, the steady state predose plasma levels of valproate were significantly higher in the valproate alone patients (90.3 ± 8.7 µg/ml) compared to the patients receiving additional anticonvulsants (75.3 ± 13.8 µg/ml) (p〈0.01). The higher dose requirements of valproate and lower predose and steady state plasma levels for those patients on multiple anticonvulsants indicate an interaction between valproate and other anticonvulsants.
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    Absolute bioavailability of quinidine in two sustained release preparations (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 45-48 
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    ISSN: 1432-1041
    Keywords: quinidine ; slow release formulation ; pharmacokinetics ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability of quinidine in two sustained release preparations A and B has been compared in three females and three males with i.v. administration of quinidine. The initial rate of oral absorption did not differ between the two drug preparations; the peak concentration was observed after 4 h both for A and B, but was significantly higher after B. A slower decrease in plasma concentration was observed after preparation A than B. Absolute bioavailability did not differ significantly between A (median value 78.4%) and B (median 87.1%). Drug absorption in vivo was in good agreement with the results of in vitro dissolution tests on both preparations. The slower decrease in plasma concentration found for the new sustained release form of quinidine should be of clinical advantage.
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    Pharmacokinetics of cephacetrile in patients undergoing haemodialysis (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 49-52 
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    ISSN: 1432-1041
    Keywords: cephacetrile ; haemodialysis ; pharmacokinetics ; renal failure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of cephacetrile were studied after its administration as a single i.v. bolus injection of 15 mg/kg body weight to 11 patients with terminal renal inpairment undergoing haemodialysis for 6 h. A two-compartment kinetic model was used to describe the biphasic decrease in plasma concentration. The quantities of antibiotic in the central and peripheral compartments, and the amounts eliminated, were calculated for different times. During haemodialysis sessions, the average pharmacokinetic parameters of cephacetrile determined at the dialyser input were: α=5.03 h−1,β=0.458 h−1, K12=2.337 h−1, K21=1.996 h−1 K13=1.154 h−1, Vc=5.508 l, Vp=6.448 l, Vdss=11.956 l. As a function of the pharmacokinetic parameters of cephacetrile, a regimen of multiple doses was established for patients with terminal renal impairment, which will guarantee safe and effective concentrations of the antibiotic.
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    Pharmacokinetics of methadone during maintenance therapy: Pulse labeling with deuterated methadone in the steady state (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 53-57 
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    ISSN: 1432-1041
    Keywords: methadone ; mass fragmentography ; pulse labeling ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A technique is presented for study of steady state kinetics of methadone using pulse labeling with deuterated methadone (d3) and mass fragmentography to measure both unlabeled and labeled methadone in blood. Seven subjects maintained on methadone for at least 10 months were admitted to a closed metabolic ward. The daily dose of unlabeled methadone (d0) was substituted by one dose of methadone-d3 and plasma levels of methadone-d0 and methadone-d3 were followed for 48 h using a precise (SD±5%) and sensitive (30 pmol/ml) mass fragmentographic technique. Plasma half-lives (t1/2) for both methadone-d0 and metadone-d3 were calculated from samples obtained 8–24 h following the dose of methadone-d3. The t1/2 of oral methadone-d3 was shorter (22±2 h) than that of methadone-d0 (52±20 h). The same pattern was observed after intravenous administration. The results indicate multiple pools of methadone in the body.
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    Prazosin, pharmacokinetics and concentration effect (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 177-181 
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    ISSN: 1432-1041
    Keywords: prazosin ; alpha receptor blockade ; blood pressure ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and effects of prazosin have been studied after intravenous and oral dosing (1 mg) to 6 normal male volunteers. The mean terminal (β) half-life was 2.9 h after intravenous and oral routes. Oral bioavailability was 56.9%. The effects of prazosin on blood pressure were more pronounced after intravenous than oral administration, and the hypotensive effect greater on erect blood pressure. There was a significant correlation (P〈0.02) between the fall in blood pressure and the plasma drug concentration after intravenous prazosin.
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    Influence of the defective metabolism of sparteine on its pharmacokinetics (1979)
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    European journal of clinical pharmacology 16 (1979), S. 189-194 
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    ISSN: 1432-1041
    Keywords: sparteine ; pharmacogenetic defect ; defective metabolism ; pharmacokinetics ; renal excretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Sparteine is metabolized by N1-oxidation, which in some subjects is defective. The defect has a pronounced effect on the kinetics of the drug. In non-metabolisers elimination of sparteine proceeds entirely via renal excretion by a capacity-limited process, 99,9% of the dose being excreted as unchanged drug. In metabolisers the drug is mainly eliminated by metabolic degradation. Pronounced differences in β-phase half-life and total plasma clearance were observed between metabolisers (156 min; 535 ml · min−1) and nonmetabolisers (409 min; 180 ml · min−1).
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    Pharmacokinetics of metformin after intravenous and oral administration to man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 195-202 
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    ISSN: 1432-1041
    Keywords: metformin ; biguanides ; pharmacokinetics ; absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The kinetics of14C-metformin have been studied in five healthy subjects after oral and intravenous administration. The intravenous dose was distributed to a small central compartment of 9.9±1.61 ( $$\bar X$$ ±SE), from which its elimination could be described using three-compartment open model. The elimination half-life from plasma was 1.7±0.1 h. Urinary excretion data revealed a quantitatively minor terminal elimination phase with a half-life of 8.9±0.7 h. After the intravenous dose, metformin was completely excreted unchanged in urine with a renal clearance of 454±47 ml/min. Metformin was not bound to plasma proteins. The concentration of metformin in saliva was considerably lower than in plasma and declined more slowly. The bioavailability of metformin tablets averaged 50–60%. The rate of absorption was slower than that of elimination, which resulted in a plasma concentration profile of “flip-flop” type for oral metformin.
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    Food-induced reduction in bioavailability of atenolol (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 327-330 
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    ISSN: 1432-1041
    Keywords: atenolol ; food intake ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of food intake on the bioavailability of the beta-adrenoceptor blocker atenolol was assessed by measurement of its single-dose kinetics in ten healthy volunteers, who took 100 mg both in the fasting state and together with a standardized breakfast. Food intake significantly shortened the time to reach peak concentration (2.7 h vs 1.5 h), but caused a significant reduction in AUC values, the mean decrease being 20%. The elimination half-life was unaffected. Atenolol, which is relatively hydrophilic, is incompletely absorbed in the fasting state, and escapes first-pass metabolism. The present findings indicate that food intake causes further impairment of its absorption, even though the absorption rate may initially be enhanced. This contrasts with previous observations on the more lipophilic beta-adrenoceptor blockers propranolol and metoprolol.
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    Multicompartment pharmacokinetics of netilmicin (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 331-334 
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    ISSN: 1432-1041
    Keywords: netilmicin ; radioenzymatic assay ; drug accumulation ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of a single dose of netilmicin (NM) was studied in 6 healthy volunteers. Elimination of the drug was followed in serum and urine for 24 h and 72 h, respectively. NM concentrations were measured with a modified radioenzymatic assay. A three compartment open model was employed to calculate the pharmacokinetic parameters. Following the rapid initial distribution, biphasic elimination with half lives of 1.99 h (t1/2β) and 36.89 h (t1/2γ) was demonstrated. Measurable amounts of NM were excreted in the urine for up to 72 h. The volume of distribution at steady-state (Vdss) of 0.68 l/kg was 3 to 4 times larger than previously reported for this antibiotic. NM plasma clearance was 91 ml/min and the renal clearance was 67 ml/min. The data indicate that on repetitive dosing the amount of drug in the body would be considerably underestimated if the prolonged terminal elimination phase were not taken into account. During prolonged treatment, accumulation of NM in renal and other tissues is likely to occur, as has been described for other aminoglycosides. The possible consequences of this pharmacokinetic behaviour are discussed.
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    Bioavailability and pharmacokinetics of cimetidine (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 335-340 
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    ISSN: 1432-1041
    Keywords: cimetidine ; enterohepatic circulation ; irregular absorption ; bioavailability ; pharmacokinetics ; volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The bioavailability and pharmacokinetics of cimetidine have been studied in healthy volunteers after administration of single intravenous (100 mg) and oral doses (100, 400 and 800 mg). After i.v. administration, the kinetics of cimetidine could be described by a linear, two compartment open model. Substantial variation in half-life was observed between subjects, with a mean value of 2.1 h (range 0.9–4.7). Cimetidine had a low hepatic extraction ratio and a high total plasma clearance, due to extensive urinary excretion of unchanged drug. After oral administration, the plasma concentration vs time curves in most subjects exhibited two marked peaks, an observation that seemed to be constant within individuals and was independent of dose. Bioavailability, estimated as the area under the plasma concentration vs time curves (AUC), after oral doses as compared to the intravenous dose, in most cases exceeded 100%. There was no correlation between bioavailability estimated as AUC and as urinary excretion of unchanged drug. These observations may indicate an enterohepatic circulatory mechanism, predominantly after oral administration. Both unchanged drug and its sulphoxide metabolite appear to be excreted in bile. The latter was shown in vitro to be reduced to cimetidine by fecal bacteria.
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  • 40
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    Haemodynamic effects and pharmacokinetics of a new selective beta1-adrenoceptor agonist, prenalterol, and its interaction with metoprolol in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 9-13 
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    ISSN: 1432-1041
    Keywords: prenalterol ; metoprolol ; haemodynamics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The haemodynamic effects of the selectiveβ 1-adrenoceptor agonist prenalterol were studied in healthy subjects before and after therapeutic doses of the selectiveβ 1-adrenoceptor blocker metoprolol. Plasma levels of the drugs were also determined in order to calculate certain pharmacokinetic variables. Intravenous infusion of prenalterol 0.13, 0.25 and 0.50 mg induced a dose-dependent decrease in total electromechanical systole (QA2) and pre-ejection period (PEP). The effect on left ventricular ejection time (LVET) was not significant. Increases in systolic blood pressure and heart rate were dose-dependent. Diastolic blood pressure did not change significantly. When metoprolol had been administered in a cumulative dose of 150 mg (mean maximal plasma level, 284 nmol/1) prenalterol had to be administered in doses that were twelve times higher than before theβ-blocker in order to induce the same haemodynamic effects. Prenalterol was rapidly distributed with an average half life of 8 min. This indicates that distribution equilibrium will be achieved within 30 min after intravenous administration. The overall elimination rate in the post-distributive phase corresponded to an average half life of 2.0 h.
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  • 41
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    Influence of food on the absorption of phenytoin in man (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 269-274 
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    ISSN: 1432-1041
    Keywords: phenytoin ; food-intake ; bioavailability ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of food intake on the absorption of phenytoin was examined in eight healthy volunteers, by study of single-dose kinetics following ingestion of phenytoin 300 mg either with a standardized breakfast or on an empty stomach. Blood samples were collected at regular intervals from 0 to 48 h, and serum concentrations of unmetabolized phenytoin were determined by gas chromatography. Serum concentrations of the major metabolite of phenytoin, 4-hydroxyphenytoin, were measured by mass fragmentography. Concurrent intake of food and phenytoin appeared to accelerate absorption of the drug from the formulation used, and the peak concentrations were significantly higher (mean increase 40%) in the postprandial than in the preprandial state. As reflected by the AUC (area under the curve), the amount of drug absorbed was increased during postprandial conditions, although the difference only reached borderline significance. It is suggested that phenytoin should always be taken in a defined relation to meals.
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  • 42
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    A pharmacokinetic study of neostigmine in man using gas chromatography-mass spectrometry (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 367-371 
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    ISSN: 1432-1041
    Keywords: myasthenia gravis ; neostigmine ; gas chromatography-mass spectrometry ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To permit rational evaluation of the empirical pharmacotherapy of myasthenia with cholinesterase inhibitors, a sensitive and selective method for the determination of neostigmine has been developed. Analysis is based on ion-pair extraction of neostigmine into methylene chloride and determination by gas chromatography-mass spectrometry (chemical ionization). As neostigmine was found to be metabolized in plasma in vitro, deuterated (d6) neostigmine was immediately added to the plasma sample as the internal standard. The limit of quantitation of the method was about 1 ng/ml (∼ 3nmol/l). The kinetics following i. v. administration were studied in four patients, who received neostigmine 2.5–3.0 mg iv to antagonize pancurone administered during anaesthesia. Elimination was rapid with a half-life t1/2 (β-slope) of 0.89±0.05 h (mean ± SE). The volume of distribution was 1.08±0.11 l/kg and plasma clearance was 0.84±0.04 l/kg/h. In three fasting myasthenic patients plasma concentrations of neostigmine were followed for 5 h after a single oral dose of 30 mg. Considerable interindividual differences in absorption were expressed in the peak concentrations, which occurred 1–2 h following drug ingestion. The bioavailability of neostigmine was estimated to be 1–2% of the ingested dose. Neostigmine concentration in plasma was found to differ considerably (up to forty-fold) between myasthenic patients on their ordinary dose-schedules of cholinesterase inhibitors.
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    Pharmacokinetics of dihydroquinidine in congestive heart failure patients after intravenous quinidine administration (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 101-105 
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    ISSN: 1432-1041
    Keywords: dihydroquinidine ; congestive heart failure ; intravenous administration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of dihydroquinidine were studied in 8 patients with congestive heart failure following a 22 min intravenous infusion of a quinidine preparation that contained 5.9% dihydroquinidine as an impurity. Using a thin layer chromatography-fluorometric assay procedure for dihydroquinidine, the post-infusion plasma dihydroquinidine concentrations declined biexponentially. The half-life of the fast and slow dispositional processes was 4.42±1.81 min and 6.52±2.40 h, respectively. The central compartment volume for dihydroquinidine in these patients was 0.44±0.11 l/kg with an overall apparent volume of distribution of 1.14±0.38 l/kg. The computed values of total body plasma clearance of dihydroquinidine ranged from 1.29 to 2.69 ml/min/kg with a mean value of 1.94±0.60 ml/min/kg. In these patients, approximately 16% of the administered dihydroquinidine dose was excreted intact into the urine in 48 h. The estimated value of renal clearance was 0.314±0.129 ml/min/kg. When compared to control cardiac patients, the data showed that the apparent volume of distribution for dihydroquinidine is smaller in patients with congestive heart failure and as a result of this diminished volume, the clearance rate of dihydroquinidine was slower. The net effect of these differences was the production of higher plasma concentrations of dihydroquinidine in the heart failure group.
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    Pharmacokinetics of cefoxitin in patients with normal or impaired renal function (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 119-124 
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    ISSN: 1432-1041
    Keywords: cefoxitin ; renal impairment ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of cefoxitin have been determined after a single i.v. injection of 15 mg/kg body weight in 10 patients with normal renal function and 20 patients with varying degrees of renal impairment. The kinetics of the antibiotic followed an open two-compartment model. In patients with normal renal function the following pharmacokinetic parameters were found: $$\begin{gathered} \begin{array}{*{20}c} {\alpha = 8.66 h^{ - 1} } & {\beta = 1.21 h^{ - 1} } & {K_{12} = 3.47 h^{ - 1} } \\ \end{array} \hfill \\ \begin{array}{*{20}c} {K_{21} = 3.17 h^{ - 1} } & {K_{13} = 3.15 h^{ - 1} } & {V_c = 4.24 l.} \\ \end{array} \hfill \\ \begin{array}{*{20}c} {V_p = 4.87 l.} & { Vd_{ss} = 9.11 l.} \\ \end{array} \hfill \\ \end{gathered}$$ In the patients with renal impairment there was a significant decrease in $$\mathop \alpha \limits_, \mathop \beta \limits_, $$ K12, K21 and K13, and an increase in the apparent volume of distribution. The degree of plasma protein binding in patients with normal renal function was 73.6% and this was diminished in patients with renal impairment. A linear relationship between K13 of cefoxitin and creatinine clearance was demonstrated. The dosage regimen for patients with renal impairment should be adjusted by modifying the dosage interval whilst maintaining the amount administered.
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    Pharmacokinetics of theophylline in young children with asthma: Comparison of rectal enema and suppositories (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 133-139 
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    ISSN: 1432-1041
    Keywords: theophylline ; asthma ; pharmacokinetics ; children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Six children, aged 2 months – 4 years, received theophylline 5–6 mg/kg intravenously. Its disposition could be described by a two-compartment open model, the mean serum half life (t1/2 β) was 3.75 h, i. e., shorter than in adults, but there was a considerable interindividual variation (1.8–7.0 h, in one patient 13.3 h). Thirteen children (2 months – 4 years) received theophylline suppositories in a dose of 3.8–5.0 mg/kg, and ten (6 months – 4 years) in a dose of 8.4–14.5 mg/kg. Absorption was slow (mean half-time 43 min), incomplete and variable (biological availability 8–100%, mean 80%). Only four of the patients given the higher dose and none given the lower dose reached a therapeutic serum concentration (10–20 µg/ml). Nine children (6 months – 4 years) received rectal enemas of theophylline 4.1–9.2 mg/kg. Absorbtion was rapid (mean half-time 5.5 min) and biological availability averaged 100%. Six patients reached a serum concentration within the therapeutic range. Using the mean values of the calculated pharmacokinetic parameters, rectal enemas providing a dose of theophylline of 6–8 mg/kg t. i. d. were computed to give serum concentrations between 8–20 µg/ml, without producing too high a level during the absorption phase.
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  • 46
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    Kinetics of salicylates in blood and joint fluid (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 279-285 
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    ISSN: 1432-1041
    Keywords: salicylate ; synovitis ; osteoarthritis ; arthritis ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Samples of blood and joint fluid from 30 patients who had taken buffered acetylsalicylic acid were examined for concentrations of total salicylates (TSA), acetylsalicylate (ASA) and salicylate (SA). The data were arranged in groups according to diagnosis of the joint disease. Analysis of the data did not show significant difference in the kinetics of TSA into blood. In groups the time to first appearance of 0.3 mg/l averaged 6.3 min for TSA; these values averaged 7.7 min for ASA and 10.9 min for SA. Close to maximum concentrations in blood averaged 18.9 mg/l for TSA, 3.3 mg/l for ASA, and 23.3 mg/l for SA. The time for first appearance of 0.3 mg/l of total salicylates in joint fluid ranged from 10 to 34 min with an average of 18.1 min; the values of ASA averaged 19.4 min and those of SA 21.9 min. The maximum concentration in joint fluid averaged 15.7 mg/l for TSA, 2.5 mg/l for ASA, and 14.5 mg/l for SA. Transport of salicylates from blood to joint fluid showed a pattern consistent with the type of joint disease. Support was found for the hypothesis that diffusion was the major factor in the movement of salicylates from blood to joint fluid.
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    The disposition of intravenous doxapram in man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 411-416 
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    ISSN: 1432-1041
    Keywords: doxapram ; intravenous infusion regimen ; pharmacokinetics ; data-point weighting ; healthy subjects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of intravenous doxapram in healthy individuals is consistent with a three-compartment open model. Doxapram was administered by bolus injection (1.5 mg · kg−1) and by intravenous infusion (6.5 mg · kg−1 for 2 h) to 5 subjects on separate occasions. There was no significant difference in mean terminal plasma half-lives (355 and 448 min) or in mean total body clearances (5.9 and 5.6 ml · min−1 · kg−1) following i. v. bolus injection or infusion respectively. In 3 subjects plasma doxapram concentrations during and after i. v. infusion agreed with those predicted from pharmacokinetic values obtained from the bolus injection study. Since mean steady-state concentrations (9.9 µg · ml−1) would be reached only after an extended interval (mean 15.2 h), a variable-rate infusion regimen was calculated to produce and maintain a concentration of 2 µg · ml−1 from 15–25 min onwards. A regimen in which the infusion rate is reduced step-wise is recommended to achieve early near-constant plasma doxapram concentrations.
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    Pharmacokinetics of a single oral dose of muzolimine in cardiac failure (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 105-108 
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    ISSN: 1432-1041
    Keywords: muzolimine ; cardiac failure ; pharmacokinetics ; high ceiling diuretics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of a new “high ceiling” diuretic, muzolimine (Bay g 2821), were investigated after a single oral dose of 40 mg in 7 patients with cardiac failure (Stages I–IV, New York Heart Association classification), and in 2 healthy subjects. Plasma concentrations peaked 1–3 h after administration and declined according to a two-compartment model. The α-phase (distribution phase) lasted until 12–16 h after administration and the mean t1/2α was 3.6 h (range 2.3–4.7) in patients, and 2.6 h (range 2.3–2.9) in healthy subjects. The mean t1/2β was 13.5 h (range 7.4–22.4) in the patients and 14.0 h (range 12.4–14.6) in healthy subjects. T1/2β was not correlated with the degree of heart failure or with the area beneath the plasma concentration curve, which varied three-fold. The renal clearance of muzolimine was in the range 2.7–15.3 ml · min−1 in 5 subjects in whom it was investigated. The pharmacokinetics of muzolimine appear not to be significantly altered by cardiac failure. The prolonged half-lives of the drug are probably responsible for the longer duration of diuretic action reported for muzolimine than for furosemide and bumetamide.
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    Absorption of digoxin in severe right heart failure (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 115-120 
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    ISSN: 1432-1041
    Keywords: digoxin ; right heart failure ; absorption ; absolute bioavailability ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of digoxin has been investigated in 8 patients before and after successful treatment of severe right heart failure.3H-digoxin 0.1 mg as a solution, and un-labelled digoxin 0.25 mg as a tablet, were given to fasted patients. Blood samples were taken at various time intervals up to 120 hours and urine was collected over the same period. The concentrations of labelled digoxin in plasma and urine were measured in a liquid scintillation counter, unlabelled digoxin was estimated by radioimmunoassay, and various pharmacokinetic parameters were calculated. There was no significant difference in the plasma concentration curves in severe right heart failure and after its successful treatment, nor did any of the calculated pharmacokinetic parameters change significantly. Therefore, inhibition of the absorption of digoxin appears unlikely. In an additional study to estimate absolute bioavailability two different groups of patients in severe right heart failure were given3H-digoxin 0.1 mg or unlabelled digoxin 0.25 mg i. v. and the pharmacokinetic parameters were compared with those from the previous study. The bioavailability of the3H-digoxin solution and of the digoxin tablet were in the same range as values previously published for healthy volunteers, and patients both with and without cardiac failure.
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  • 50
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    Plasma levels and negative chronotropic effect of metoprolol following single doses of a conventional and sustained-release formulation (1979)
    Springer
    European journal of clinical pharmacology 15 (1979), S. 97-103 
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    ISSN: 1432-1041
    Keywords: metoprolol ; tachycardia ; healthy subjects ; conventional tablets ; slow release tablets ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma levels and associated reduction in exercise-induced tachycardia have been examined following the administration of single doses of metoprolol in conventional and slow-release tablets at different times to six healthy male subjects. The study was carried out in two parts. Initially, the tablets were given at 9 a. m. and the subjects were studied up to 14 h and then at 24 h. Subsequently, the same doses were given at 9 p. m. and the subjects were studied 12–24 h after drug administration (i. e. 9 a. m.–9 p. m. the next day). After giving the slow-release tablets the peak plasma levels were significantly lower but the drug persisted in the plasma at higher levels than after the conventional tablet. However, the beta-blocking effect was comparable from the two dosages. The results obtained for the period 12–24 h after the evening dose differed from the corresponding values after morning administration in that the plasma levels were higher and the betablocking effects more marked. Furthermore, the half-life values calculated from these data were significantly longer.
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    Plasma and urinary levels of triamterene and certain metabolites after oral administration to man (1979)
    Springer
    European journal of clinical pharmacology 16 (1979), S. 39-44 
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    ISSN: 1432-1041
    Keywords: triamterene ; pharmacokinetics ; diuretic effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The plasma and urinary levels of triamterene and two metabolites were measured using a specific method of analysis. Urinary excretion was completed after 48 h, which permitted a rough estimate of its half-life as longer than two hours. The areas under the curve were 672.5±160.3 and 1.311.3±399.1 µg/ml × h after the triameterene 150 mg and 300 mg p.o., respectively and correspondingly 4.2±1.4% and 3.7±0.6% of the dose were excreted as unchanged drug. The principal metabolite of triamterene found was the sulfate conjugate. The area under the curve of this metabolite amounted to 6.672±2.120 and 11.941±5.005 µg/ml × h after the of 150 mg and 300 mg triamterene doses, respectively. The urinary excretion of the metabolite varied between 25.0±4.0% and 17.5±3.5% of the dose after either dose. In healthy subjects an effect on sodium excretion was observed after a dose of 150 mg, whereas the potassium-retaining effect was observed only after the dose of 300 mg.
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    Acetobacter bacteriophage A-1 (1979)
    Springer
    Archives of microbiology 121 (1979), S. 193-197 
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    ISSN: 1432-072X
    Keywords: Acetobacter suboxydans ; Bacteriophage A-1 ; Restriction ; Modification ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A bacteriophage ofAcetobacter suboxydans was isolated and found to correspond to type A phage according to Bradley's classification. The phage contains double stranded DNA. The length of the latency period and burst size could not be precisely determined because of apparent non-synchronous release of phage from single infective cycles. The host range was determined using 24 strains ofAcetobacter andGluconobacter species. Evidence for a probable occurence of host determined restriction and modification was obtained withAcetobacter suboxydans strain ATCC 621. The phage is designated A-1 and it is the first one to be reported forAcetobacter.
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    Bdellovibrio-like parasite of cyanobacteria symbiotic in marine sponges (1979)
    Springer
    Archives of microbiology 123 (1979), S. 101-103 
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    ISSN: 1432-072X
    Keywords: Bdellovibrio ; Cyanobacteria ; Marine sponges ; Symbiosis ; Infection ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A bdellovibrio-like bacterium was observed infecting unicellular symbiotic cyanobacteria in two coral reef sponges, Neofibularia irata and Jaspis stellifera. The infecting bacterium, which was located between the cell wall and the cytoplasmic membrane of the cyanobacteria, was similar in size and appearance to previously described bdellovibrios. This observation is believed to extend the host range of the bdellovibrios.
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    Methanogenium, a new genus of marine methanogenic bacteria, and characterization ofMethanogenium cariaci sp. nov. andMethanogenium marisnigri sp. nov. (1979)
    Springer
    Archives of microbiology 121 (1979), S. 147-153 
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    ISSN: 1432-072X
    Keywords: Methanogenium cariaci ; Methanogenium marisnigri ; Marine methanogenic bacteria ; Ultrastructure ; TaxonomyMethanogenium gen. nov.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new genus of marine methanogenic bacteria and two species within this genus are described.Methanogenium is the proposed genus andMethanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells ofMethanogenium marisnigri are of similar shape but smaller diameter thanM. cariaci. The colonies ofM. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens.
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    A comparative ultrastructural study of the ascospores of some Saccharomyces and Kluyveromyces species (1979)
    Springer
    Archives of microbiology 121 (1979), S. 53-59 
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    ISSN: 1432-072X
    Keywords: Saccharomyces ; Kluyveromyces ; Ultrastructure ; Ascospore wall ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three types of structure of the ascospore wall were found among the haploid Saccharomyces species examined: a warty wall (S. rouxii), a smooth wall with a single electron-light inner layer (S. bailii) and a smooth wall with a double light inner layer (S. montanus, S. florentinus). The latter type also occurred in Kluyveromyces thermotolerans and K. waltii. In K. fragilis spores the wall had a single light inner layer. The taxonomic implications of these findings were discussed.
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    Electron microscopic study on the quaternary structure of the isolated particulate alcohol-acetaldehyde dehydrogenase complex and on its identity with the polygonal bodies of Clostridium kluyveri (1979)
    Springer
    Archives of microbiology 120 (1979), S. 255-262 
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    ISSN: 1432-072X
    Keywords: Alcohol dehydrogenase ; Acetaldehyde dehydrogenase ; Clostridium kluyveri ; Electron microscopy ; Polygonal bodies ; Enzyme complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The alcohol-acetaldehyde dehydrogenase complex of Clostridium kluyveri has been separated from contaminating β-hydroxybutyryl-CoA dehydrogenase by repeated precipitation with manganese and ammonium sulfate. Mn++ was required for maximum alcohol dehydrogenase activity. The molecular weight of the enzyme complex was 194,000 as determined by sucrose density gradient centrifugation. The enzyme complex has been shown to contain two types of subunits with molecular weights of 55,000±2,600 and 42,000±1,200, respectively which are arranged in “H”-shaped particles. In solutions with an ionic strength above 25 mM the enzyme complex precipitated in the form of lumps as has been shown with specific ferritin-conjugated antibodies. These lumps are assumed to be aggregated polygonal bodies present in C. kluyveri.
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    R-Bodies in newly isolated free-living hydrogen-oxidizing bacteria (1979)
    Springer
    Archives of microbiology 121 (1979), S. 9-15 
    Details
    ISSN: 1432-072X
    Keywords: R-Bodies ; Kappa particles ; Free-living hydrogen bacteria ; Induction ; Electron microscopy ; Chemical composition ; Defective prophages ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract R-Bodies have been found in a recently isolated pseudomonas-like free-living hydrogen oxidizing bacterium. Their isolation, fine structure and chemical composition are described and compared with the R-bodies from the kappa particles (Caedobacter), obligate endosymbionts of Paramecium aurelia. The 2K 1 R-bodies exhibited essential characteristics of the kappa R-bodies; however, their size and some other structural aspects proved that they represent a new type of R-bodies. The presence of phage tail-like particles in cells induced with Mitomycin C is in favour of the hypothesis that the R-bodies might be coded by defective prophages, or by extrachromosomal elements.
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    URL: http://dx.doi.org/10.1007/BF00409199
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    Capnocytophaga: New genus of Gram-negative gliding bacteria. II. Morphology and ultrastructure (1979)
    Springer
    Archives of microbiology 122 (1979), S. 17-27 
    Details
    ISSN: 1432-072X
    Keywords: Gliding bacteria ; CO2-requiring ; Periodontal disease ; Gram-negative ; Ultrastructure ; Capnocytophaga
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gram-negative, anaerobic gliding bacteria were isolated from normal supragingival plaque and from periodontal lesions. Isolates could be divided into two size classes: small 2.4–4.2 μm×0.38–0.5 μm and large 4.8–5.8 μm×0.42–0.6 μm cells. The outer membrane was either loose-fitting and wavy, or taut, and of variable thickness. An electron-dense fuzz was discernible on several of the isolates. The periplasmic region was of variable electron-density. The genus Capnocytophaga has been proposed for these organisms based on morphological and cultural characteristics.
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    URL: http://dx.doi.org/10.1007/BF00408041
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    The cell cycle of Bacillus subtilis as studied by electron microscopy (1979)
    Springer
    Archives of microbiology 123 (1979), S. 173-181 
    Details
    ISSN: 1432-072X
    Keywords: Bacillus subtilis ; Cell cycle ; DNA replication ; Cell division ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bacillus subtilis strain Marburg was grown exponentially with a doubling time of 65 min. To follow the time course of various cell cycle events, cells were collected by agar filtration and were then classified according to length. The DNA replication cycle was determined by a quantitative analysis of radioautograms of tritiated thymidine pulse labeled cells. The DNA replication period was found to be 45 min. This period is preceded and followed by periods without DNA synthesis of about 10 min. The morphology and segregation of nucleoplasmic bodies was studied in thin sections. B. subtilis contains two sets of genomes. DNA replication and DNA segregation seem to go hand in hand and DNA segregation is completed shortly after termination of DNA replication. Cell division and cell separation were investigated in whole mount preparations (agar filtration) and in thin sections. Cell division starts about 20 min after cell birth; cell separation starts at about 45 min and before completion of the septum.
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    URL: http://dx.doi.org/10.1007/BF00446817
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    Solid-solid reactions, I: Experimental study of barium metatitanate synthesis (1979)
    Springer
    Oxidation of metals 13 (1979), S. 77-88 
    Details
    ISSN: 1573-4889
    Keywords: BaTiO3 ; kinetics ; solid state
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The solid-state reaction between barium carbonate and rutile powders to form barium metatitanate BaTiO3 was studied by thermogravimetric analysis, X rays, and microscopy. Phase-stability domains were drawn in a temperature— $${\text{p}}_{CO_2 } $$ , diagram. The dependence of the reaction kinetics on $${\text{p}}_{CO_2 } $$ , $${\text{p}}_{O_2 } $$ or $${\text{p}}_{N_2 } $$ is discussed. In particular, the rate continuously decreases when $${\text{p}}_{CO_2 } $$ , or $${\text{p}}_{N_2 } $$ increases, but it reaches a maximum as a function of $${\text{p}}_{O_2 } $$ .
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    URL: http://dx.doi.org/10.1007/BF00715871
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    The oxidation of Fe-Cr surface and bulk alloys at 300°C (1979)
    Springer
    Oxidation of metals 13 (1979), S. 283-298 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; surface alloys ; Fe-Cr alloys ; iron ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation behavior of several surface and bulk Fe-Cr alloys and iron at 300°C and 4×10−6 Torr oxygen was studied. The surface alloys were fabricated by implantation of 25 keV Cr ions into the outermost 300Å of polycrystalline iron samples. The oxide thickness as a function of oxygen exposure was obtained using proton-excited X-ray analysis, and composition profiles of oxide films were obtained using Auger electron spectroscopy and ion sputtering. The addition of Cr to Fe by surface and bulk alloying caused the oxidation rate to decrease and changed the oxidation kinetics from parabolic (for Fe) to logarithmic (for Cr concentrations ≥4.7at.%). Interpretation of the data in terms of simple oxidation theories indicates that the Cr additions may reduce the oxidation rate by altering the electronic properties of the metal-oxide interface.
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    URL: http://dx.doi.org/10.1007/BF00603672
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    Oxidation of Fe-C alloys at 700°C (1979)
    Springer
    Oxidation of metals 13 (1979), S. 255-272 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; Fe-C ; graphite deposition ; nonadherent oxide ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of Fe-C alloys containing 0.5 and 1.0% C was studied in 1 atm O2 at 700° C. The oxidation rate is considerably slower than for pure Fe. The oxide scale formed is detached, multilayered, and overoxidized, containing little or no FeO. A thin film of graphite was identified at the metal-oxide interface by electron diffraction. It is proposed that the slow oxidation and abnormal scale are caused by a residue of graphite left at the metal surface from the oxidation of Fe3C. This inhibition of the oxidation of Fe by carbon at 700°C is in contrast to the stimulation observed at 500°C.
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    URL: http://dx.doi.org/10.1007/BF00603670
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    Kinetics interpretation of NiO electrical conductivity under low oxygen pressures (1979)
    Springer
    Oxidation of metals 13 (1979), S. 301-309 
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    ISSN: 1573-4889
    Keywords: NiO ; Electrical conductivity ; gas-solid equilibria ; kinetics ; equivalent circuit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In a previous work it has been stated that the NiO electrical conductivity changes connected to the oxygen pressure changes may be considered as a transitory phenomenon. A mixed kinetics case controlled by the formation of surface cation vacancies and their diffusion in the bulk is proposed to explain the reaction process. By means of an equivalent electrical circuit in good agreement with the kinetics model it was possible to reproduce the experimental phenomenon.
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    URL: http://dx.doi.org/10.1007/BF00609302
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    Kinetics and mechanism of high-temperature sulfur corrosion of Fe-Cr-Al alloys (1979)
    Springer
    Oxidation of metals 13 (1979), S. 481-504 
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    ISSN: 1573-4889
    Keywords: kinetics ; sulfidation ; Fe-Cr-Al alloys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The influence of aluminium on the kinetics and mechanism of high-temperature sulfidation of Fe-Cr alloys containing 20 at.% chromium has been investigated. It has been found that the addition of aluminum greatly improves the scaling resistance of Fe-Cr alloys against attack by sulfur vapors at high temperatures.
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    URL: http://dx.doi.org/10.1007/BF00812774
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    Low-temperature oxidation of Fe-24 wt.%Cr (1979)
    Springer
    Oxidation of metals 13 (1979), S. 437-456 
    Details
    ISSN: 1573-4889
    Keywords: Fe-Cr ; oxidation ; kinetics ; oxide morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Ferritic polycrystalline Fe-24 wt.% Cr was oxidized in pure oxygen at 190 ≤ T≤490° C and pressures in the range 5.3×10−2–13.3 Pa for periods of up to 5 hr. The reaction proceeded in three stages. An initial period of accelerating rate was accompanied by oxide island nucleation and growth. Following island coalescence the rate was approximately logarithmic at low temperatures and somewhat slower than parabolic at high temperatures. Rate control during this period was thought to be due to mass transport through the oxide grain boundaries left by the island impingement process. During these first two stages the oxide formed was γ-M2O3 with possibly some spinel. The final stage of reaction involved the appearance of α-M2O3 on the outer oxide surface and a substantial slowing of the oxidation rate due to the low diffusivity in this phase.
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    Solid-solid reactions, II: Mechanism of barium metatitanate synthesis (1979)
    Springer
    Oxidation of metals 13 (1979), S. 89-104 
    Details
    ISSN: 1573-4889
    Keywords: BaTiO3 ; kinetics ; solid state ; mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The authors propose a mechanism for the solid-solid reaction BaCO3+ TiO2→BaTiO3+CO2. This mechanism is based on the real structure of the present semiconductors. The reactions at different interfaces and the diffusing species are identified. The reaction rates are calculated and the dependence of the reaction rate upon O2, N2, and CO2 gas pressure is interpreted and discussed.
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    Oxidation of high-chromium Ni-Cr alloys (1979)
    Springer
    Oxidation of metals 13 (1979), S. 119-158 
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    ISSN: 1573-4889
    Keywords: nickel-chromium alloys ; oxidation ; high temperature ; kinetics ; mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of binary Ni-Cr alloys containing 44 and 50 wt. % Cr has been studied over a range of oxygen partial pressures at temperatures between 800 and 1100°C. The effects of cold work, surface preparation, and distribution of the Cr-rich second phase have been studied. The oxidation behavior is complex and cannot be described by a single model. The oxide grows by short-circuit diffusion as well as bulk transport through Cr 2 O 3 scales. The scale-growth mechanism includes extensive metal-oxide separation requiring Cr vapor transport to the scale, compressive stresses within the oxide which result in scale bulging and cracking, and the formation of a second oxide layer which results in voids being incorporated into the scale. Any factor which reduces the oxide grain size, such as cold work, finer distribution of the Cr-rich α phase or reduced oxygen pressure, results in an increased oxidation rate of binary alloys because of an increased number of grain-boundary short-circuit diffusion paths.
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    URL: http://dx.doi.org/10.1007/BF00611976
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    Distribution and fine structure of the lymphatic system in the human testis (1979)
    Springer
    Cell & tissue research 200 (1979), S. 15-27 
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    ISSN: 1432-0878
    Keywords: Lymph vessels ; Testis ; Man ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of lymph vessels in the human testis was investigated using ink injection methods, and light and electron microscopy. Lymph capillaries occur in the septula testis but are absent in the intertubular tissue. They consist of endothelial cells provided with an incomplete basal lamina and anchoring filaments of the adjacent connective tissue. Frequently, the endothelial cells are separated by gaps measuring up to 2μm. The lymph capillaries of the septula testis are connected to lymph vessels in the rete testis and tunica albuginea. These vessels have occasional smooth muscle cells and valves. At the posterior margin of the testis, the network of lymph vessels merges into collecting ducts, which together with vessels derived from the rete testis are drained by the lymphatic system in the spermatic cord.
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    URL: http://dx.doi.org/10.1007/BF00236883
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    Biosynthesis of the basal lamina as a result of interaction between thyroid and mesenchymal cells in culture (1979)
    Springer
    Cell & tissue research 200 (1979), S. 69-81 
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    ISSN: 1432-0878
    Keywords: Thyroid follicular cells ; Basal lamina, biosynthesis ; Cellular interaction ; Cell culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Porcine thyroid cells were cultured alone or in mixed cultures with mesenchymal cells. The formation of a basal lamina in vitro was investigated ultrastructurally. Follicular reassociation of thyroid cells occurred in both types of culture; however, it was followed by formation of the basal lamina only when mesenchymal cells were present. The present findings suggest an epithelial origin of the basal lamina resulting from an interaction with mesenchymal cells.
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    Ultrastructural identification of non-adrenergic, non-cholinergic nerves in the rat anococcygeus muscle (1979)
    Springer
    Cell & tissue research 200 (1979), S. 257-271 
    Details
    ISSN: 1432-0878
    Keywords: Anococcygeus muscle ; Innervation ; P-type nerves ; Purinergic nerves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the rat anococcygeus muscle has been investigated ultrastructurally following fixation with a modified chromaffin reaction for the demonstration of biogenic amines (Tranzer and Richards, 1976). Three types of nerve profiles were revealed: (1) 60–70 % of the profiles are adrenergic; (2) less than 5% of the profiles appear to be cholinergic; (3) up to 40% of the profiles are distinguished by the presence of a characteristically high proportion of electron-opaque, chromaffin-negative vesicles, 85–110nm in diameter. This third type of profile was not affected by 6-OHDA, and is considered to represent the non-adrenergic, non-cholinergic inhibitory innervation of this tissue. Because of the morphological similarity of this nerve type, apart from the smaller vesicle size, to classical peptidergic nerve endings, they have been termed “small p-type” (sp-type). These results are discussed in relation to a previous report describing only two types of nerve profiles in this tissue (Gillespie and Lüllmann-Rauch, 1974).
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    A stereological ultrastructural study of stimulated peritoneal macrophages in the germ-free mouse (1979)
    Springer
    Cell & tissue research 200 (1979), S. 299-309 
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    ISSN: 1432-0878
    Keywords: Germ-free mice ; Inflammation ; Macrophages ; Peritoneum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peritoneal macrophage ultrastructure was analysed stereologically in germ-free mice given a single intraperitoneal injection of sterile, pyrogen-free saline. Thus the stimulant was non-particulate, non-antigenic and inorganic, and effects of immune reactions were minimal. Macrophages were recovered 1, 6, 24 and 72 h after stimulation. A sequence of structural alterations is reported which may be fundamental to macrophage activation. The plasma membrane and nuclear envelope increased in area within only 1 h of saline injection. During the next 5 h loss of plasma membrane, probably by pinocytosis, caused cellular “rounding” and clear-cut alteration in surface configuration. At the same time lysosome-like granules enlarged but decreased in number. By 24 h most cellular structures and compartments (including the plasma membrane) were enlarged. Morphological evidence of nuclear activation accompanied a rather modest enlargement of the nucleus at this stage. The RER hypertrophied last and must, therefore, be judged sufficient in resident macrophages to support the initial growth response which results after stimulation. Thus hypertrophy was observed eventually in every structure examined. Even the minimally activated macrophages resident in the peritoneum of germ-free mice respond readily to stimulation.
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    The tanycyte of the rat median eminence (1979)
    Springer
    Cell & tissue research 200 (1979), S. 329-334 
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    ISSN: 1432-0878
    Keywords: Median eminence ; Axon terminals ; Tanycytes ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present ultrastructural study proves the existence of nerve terminals closely apposed to the plasmalemmata of tanycytes in the rat median eminence. Several of these “axo-tanycytic” endings display remarkable accumulations of agranular endoplasmic reticulum in the form of pleomorphic vesicles which are closely apposed on either side of the plasma membrane of each cell compartment. Some of these vesicular profiles give the impression of structural continuity across both membrane systems. This phenomenon is discussed in the context of being a potential substratum for communication between both cell compartments.
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    Ultrastructure of an excitatory synapse (1979)
    Springer
    Cell & tissue research 200 (1979), S. 291-298 
    Details
    ISSN: 1432-0878
    Keywords: Excitatory synapse ; Lateral line-canal organ ; Synaptic body ; Ultrastructure ; Lota lota (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the afferent synapse in hair cells of the lateral line-canal organ was studied using different fixation and staining techniques. Glutaraldehyde-fixed tissue without post-osmication, contrasted by section staining with uranyl acetate and lead citrate, was compared with (a) osmium tetroxide-fixed tissue followed by the same staining procedure, and with (b) glutaraldehyde-fixed tissue, block-impregnated with phosphotungstic acid (PTA). The results reveal a pronounced heterogeneity in the composition of the synaptic body, reflecting regional differences in chemical affinity to the fixatives and staining agents. It is proposed that the “intracleft substance”, the synaptic structure defined by the PTA staining technique, is actually due to the glutaraldehyde fixation procedure and is apparently the outer leaflet of the postsynaptic membrane. A special technique that allows alternate sections of a series to be differentially stained for electron microscopy is proposed.
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    Are there specialized junctions in the pars maculata of the distal tubule? (1979)
    Springer
    Cell & tissue research 200 (1979), S. 337-344 
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    ISSN: 1432-0878
    Keywords: Glomerulo-tubular feedback ; Tight junctions ; Macula densa ; Distal tubule ; Electron microscopy ; Freeze fracture ; Horseradish peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present study the tight junctions at the macula densa were compared to those of the adjacent straight and convoluted segments of the distal tubule using freeze fracturing and thin sectioning techniques. Only insignificant differences were found in the number of strands and the apico-basal depth of the tight junctions in the three distal tubular segments of rat, dog and tree shrew. In experiments with horseradish peroxidase on mice and tree shrews, the tracer did not penetrate the apical junctions in any of the distal tubular segments. Our findings do not support the concept of considerably higher permeability of the tight junctions at the macula densa, as previously reported. Gap junctions were never observed in the distal nephron. The present results suggest that the glomerulo-tubular feedback is more likely to be mediated by transcellular resorption of solutes than by passive diffusion through a leaky paracellular shunt pathway.
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    Ultrastructural morphometry of blastogenesis I: Transformation of small lymphocytes stimulated in vivo with dinitrochlorobenzene (1979)
    Springer
    Cell & tissue research 200 (1979), S. 495-509 
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    ISSN: 1432-0878
    Keywords: T-lymphocytes ; Blast cells ; Lymph node ; Electron microscopy ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes in the volumes and surfaces of subcellular compartments of unstimulated small lymphocytes and immunoblasts in mouse axillary lymph nodes have been established using stereological techniques. Blast transformation was induced in vivo with dinitrochlorobenzene (DNCB). Cell samples were obtained by random sampling regimes applied at light and electron microscopic levels. From electron micrographs the volume densities of euchromatin, heterochromatin, nucleoli, mitochondria, Golgi apparatus and rough endoplasmic reticulum were determined. Cell surface/volume ratios were also computed. By estimating mean nuclear volumes using light microscopy, it was possible to calculate absolute compartmental volumes and to evaluate the plasma membrane surface areas of average cells. Transformation in this model was characterized by a considerable cellular hypertrophy and a substantial increase in plasmalemma surface. Hypertrophy was the consequence of increases in the volumes of all measured intracellular compartments, notably euchromatin and “residual cytoplasm” (including ground cytoplasm and free ribosomes). These changes are discussed in the context of the altered metabolic status of cells.
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    Functional morphology of the midgut of Aedes aegypti L. (Insecta, Diptera) during blood digestion (1979)
    Springer
    Cell & tissue research 200 (1979), S. 193-203 
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    ISSN: 1432-0878
    Keywords: Mosquitoes ; Midgut ; Ultrastructure ; Stereology ; Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Morphometrische Untersuchungen des Magenepithels von A. aegypti weisen darauf hin, daß die Verdauung des ersten Blutmahls in eine Reihe von Phasen gegliedert werden kann, die sich mit physiologischen Daten aus der Literatur korrelieren lassen. In einer Phase Ia (0–10 h nach Blutmahl [BM]) entfalten sich die “whorls” des rauhen endoplasmatischen Retikulums, die Golgi-Zonen werden größer, und das basale Labyrinth wird erweitert. Dies stimmt mit Synthese- und Sekretionsprozessen (z.B. peritrophische Membran, Esterasen, Lipasen) und mit Transportvorgängen durch das Magenepithel überein. In Phase Ib (10–20 h nach BM) nehmen die gemessenen zellulären Parameter weiter zu und weisen damit auf hohe Synthese- und Sekretionsaktivitäten (z.B. Verdauungsenzyme) hin. In Phase Ic (20–30 h nach BM) zeigen die an Synthese und Sekretion beteiligten Zellstrukturen, in Übereinstimmung mit der maximalen Proteasenaktivität im Darm, immer noch hohe Werte. Vergrößerte Mikrovillioberfläche, auffallende Lipideinschlüsse und Auftreten von Glykogendepots im Magenepithel deuten auf erhöhte Resorptions-, Speicher- und Transportfunktionen der Zellen hin. In Phase II (30–36 h nach BM) läßt sich anhand der strukturellen Veränderungen der Wechsel von Synthese- und Sekretionvorgängen zu Resorption, teilweiser Speicherung und Transport von Verdauungsprodukten erkennen. In Phase III (36–72 h nach BM) wird der Zellapparat in Übereinstimmung mit dem Ende der Verdauung reduziert. Lipid- und Glykogendepots werden mobilisiert und verschwinden fast vollständig aus den Magenepithelzellen.
    Notes: Summary Morphometric analysis of the epithelial lining of the stomach of A. aegypti suggests that digestion of the first blood meal in the stomach of this species can be viewed as a series of phases that can be correlated with physiological data from the literature. In phase Ia (0–10 h after blood meal [abm]) the whorls of the rough endoplasmic reticulum unfold, the Golgi zones increase, and the basal labyrinth is enlarged. This coincides with processes of synthesis and secretion (e.g., peritrophic membrane, esterases and lipases) and transport by the stomach epithelium. In phase Ib (10–20 habm) the cellular parameters measured further increase, indicating high synthetic and secretory activities (e.g., digestive enzymes). In phase Ic (20–30 habm) cell structures involved in synthesis and secretion still exhibit high values coinciding with maximal activity of proteases in the gut. Enhanced surface area of microvilli, prominent lipid inclusions, and appearance of glycogen deposits in the gut epithelium suggest increased absorption, storage, and transport functions of the stomach cells. In phase II (30–36 habm) structural alteration points to a gradual shift from synthesis and secretion to absorption, partial storage, and transport of nutrients. In phase III (36–72 habm) the cellular apparatus is reduced concomitant with the ending of the digestive cycle. Lipid inclusions and glycogen deposits disappear from the stomach epithelum.
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    Demonstration of acid phosphatase activity induced by 20-hydroxyecdysone in the fat body of Calliphora (1979)
    Springer
    Cell & tissue research 200 (1979), S. 435-442 
    Details
    ISSN: 1432-0878
    Keywords: Fat body ; Calliphora ; Electron microscopy ; Cytochemistry ; Ecdysterone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the larval fat body of Calliphora erythrocephala, protein accumulation and autophagic activity occur prior to the onset of puparium formation. The involvement of the lysosomal system in the degradation of sequestered protein and cell organelles can be demonstrated by the electron microscopical cytochemical localization of the lysosomal marker enzyme acid phosphatase in so-called protein granules. These granules contain not only newly synthetized or absorbed protein but also remnants of cell organelles such as mitochondria and endoplasmic reticulum. Ligation of the larvae behind the brain-ring gland complex prevents the appearance of these acid phosphatase positive granules. They can be induced in ligated larvae by the injection of 20 hydroxyecdysone into the abdomen. These findings are briefly discussed in relation to the role of moulting hormones in normal development, especially with regard to the induction of autophagic activity.
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    URL: http://dx.doi.org/10.1007/BF00234854
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    An electron microscopic study of lipid absorption in the pyloric caeca of rainbow trout (Salmo gairdnerii) fed wax ester — rich zooplankton (1979)
    Springer
    Cell & tissue research 200 (1979), S. 475-486 
    Details
    ISSN: 1432-0878
    Keywords: Lipid absorption ; Pyloric caeca ; Electron microscopy ; Feeding experiment ; Rainbow trout
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rainbow trout were killed 4 and 18 h after being fed wax ester-rich marine Zooplankton and the absorptive epithelium of the pyloric caeca examined by electron microscopy. Numerous osmiophilic drops were seen in the lamina propria underlying the epithelium of fish killed at both times, but these drops were only abundant within columnar epithelial cells of fish killed 4 h after feeding. Pinocytotic profiles were not common at the luminal plasma membranes, nor were osmiophilic droplets seen in the terminal web area between the luminal plasma membrane and the extensive smooth endoplasmic reticulum. Numerous osmiophilic droplets, 30–100 nm in diameter, were present in the cisternae of the smooth endoplasmic reticulum with up to five separate droplets per individual cisterna. Columnar epithelial cells also contained up to 100 large osmiophilic drops (“conglomerates”) which tended to be concentrated in the supranuclear (Golgi) regions. The conglomerates were 250–1200 nm in diameter and were themselves made up of smaller droplets 30–400 nm in diameter. Conglomerates were present both within intracellular membranes and free in the cytoplasm. Osmiophilic droplets in the intercellular spaces and lamina propria were similar in size to individual droplets within conglomerates. We conclude that triacylglycerols are elaborated in the smooth endoplasmic reticulum, transferred to and processed in the Golgi region and finally discharged serosally as chylomicron-like particles of not greater than 400 nm diameter.
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    URL: http://dx.doi.org/10.1007/BF00234857
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    A new type of synapse in the ventral cochlear nucleus (1979)
    Springer
    Cell & tissue research 198 (1979), S. 373-380 
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    ISSN: 1432-0878
    Keywords: Ventral cochlear nucleus ; Calyceal processes ; Flattened synaptic vesicles ; Ultrastructure ; Morphometric study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In this paper we report the appearance of flat vesicle-containing endings in aldehyde-fixed ventral cochlear nucleus of rats with qualitative and quantitative properties suggesting they should be identified as calyceal processes. Their synaptic vesicles are elongate and significantly smaller than the vesicles in the calyces of Lenn and Reese (1966). Therefore these endings are flat vesicular calyceal processes, possibly of inhibitory function.
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    URL: http://dx.doi.org/10.1007/BF00232018
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    Control of the pars intermedia of the lizard, Anolis carolinensis (1979)
    Springer
    Cell & tissue research 198 (1979), S. 411-426 
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    ISSN: 1432-0878
    Keywords: Intermediate lobe ; Hypophysis ; Ultrastructure ; Colour change ; Control mechanisms ; Anolis carolinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the intermediate lobe of the hypophysis was studied in Anolis carolinensis with the use of a threefold aldehyde fixative. Lizards with a brown skin were selected. The possibility of two types of secretory cells is discussed; neither cell type is innervated. Type I cells are rarely found and contain dense granules approximately 0.3 μm in diameter; Type II cells vary widely in secretory activity. Most of the Type II cells contain a large number of dense secretory granules (up to about 1.3 μm in diameter) almost filling the cytoplasm. Rough endoplasmic reticulum (RER), Golgi apparatus and mitochondria are poorly developed. Only some of these cells show signs suggesting a high secretory activity, namely a well developed RER, Golgi apparatus and numerous mitochondria. In these cells the RER sometimes forms large intracisternal droplets (up to 7 μm in diameter). Two of the animals exhibited a more uniform, high secretory activity. Large (about 2 μm in diameter), pale vacuoles, probably of extracellular character, were found mostly in the vicinity of the perivascular septum. Their role in the release of MSH is discussed. The present data, which are discussed with reference to earlier findings (Forbes, 1972), form the morphological basis for an experimental study on regulation of MSH release (Larsson et al., 1979).
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    URL: http://dx.doi.org/10.1007/BF00234186
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    Formation of sarcomeres in the embryonic heart of the lobster (1979)
    Springer
    Cell & tissue research 198 (1979), S. 477-486 
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    ISSN: 1432-0878
    Keywords: Embryonic heart ; Myogenesis ; Sarcomere ; Crustacea (Homarus americanus) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cardiomyoblasts in the myocardium of embryonic lobsters at 3–4 weeks and 6 months of development were examined with the transmission electron microscope in order to describe the events in the formation of sarcomeres in a neurogenic cardiac system. Thick and thin myofilaments appear first in the cell periphery near the sarcolemma. They align in parallel in a sequential fashion to form consecutive sarcomeric units. Well-defined A and I bands appear before any semblance of a Z line is present. The initial sarcomere is anchored to the sarcolemma by the insertion of thin myofilaments into a region of electron dense material associated intimately with the sarcolemma. Myofibrils grow outward in several planes away from the electron-dense regions of membrane that serve as focal points for myofibril formation.
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    URL: http://dx.doi.org/10.1007/BF00234192
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    Quantitative comparison of low- and high-output neuromuscular synapses from a motoneuron of the lobster (Homarus americanus) (1979)
    Springer
    Cell & tissue research 198 (1979), S. 455-463 
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    ISSN: 1432-0878
    Keywords: Neuromuscular synapses ; Presynaptic density ; Ultrastructure ; Serial sections ; Crustaceans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Representative examples of lowand high-output neuromuscular synapses between motoneuron and distal accessory flexor muscle of the lobster were selected on the basis of their mean quantal content, and subsequently analysed by serial section electron microscopy. The high-output terminal has twice as many synapses as the low-output terminal. However, since the mean surface area of synapses is significantly smaller in the high-output terminal than in the low-output one, the total synaptic surface area between the two types of terminals is similar. Also, though the high-output terminal possesses a greater number of presynaptic dense bodies than its low-output counterpart, the mean number per synapse is similar for the two terminals. The terminals, however, differ significantly in the size of their dense bodies. Thus both the mean and total surface area of these bodies is greater in the high-output terminal than in the low-output one. Moreover, the mean ratio of dense body area to synaptic area is significantly greater for the high-output terminal than for its low-output counterpart. This difference in dense body area parallels the difference in quantal content of synaptic transmission between the lowand high-output terminals and supports the hypothesis that presynaptic densities represent the ultrastructural correlates of transmitter mobilization and/or release.
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    URL: http://dx.doi.org/10.1007/BF00234190
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    The effect of L-DOPA on the ultrastructure of the adenohypophysis of the Chinese quail, Excalfactoria chinensis (1979)
    Springer
    Cell & tissue research 198 (1979), S. 521-526 
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    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Electron microscopy ; L-DOPA ; Lysosomes ; Chinese quail, Excalfactoria chinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intraperitoneally injected L-DOPA was found to stimulate strongly the lysosomal system of all of the cell types of the adenohypophysis. We suggest that this amine may play a role in the regulation of the secretory activity of the gland by mediating the lysosomal activity, this role being of variable importance according to the fluctuations in hormonal activity. Ultrastructural changes occur in some cell types following injection of L-DOPA. The question as to whether these changes are induced directly by L-DOPA or via the monoaminergic system of the hypothalamus and its hypophysiotropic hormones is discussed.
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    URL: http://dx.doi.org/10.1007/BF00234195
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    Effects of pimozide on the ultrastructure of the pars distalis in the rat (1979)
    Springer
    Cell & tissue research 199 (1979), S. 483-492 
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    ISSN: 1432-0878
    Keywords: Pituitary gland ; Rat ; Luteotroph cells ; Pimozide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of pimozide, a dopamine receptor-blocking agent, were studied in the pars distalis of the rat. The animals received 100μg/100 g pimozide daily for 5, 10, 15, and 20 days. Pimozide induces striking ultrastructural changes after 5 days of treatment. The number of luteotroph (LTH) cells is significantly increased; they display characteristics of stimulation. The extrusion of granules into the intercellular space via exocytosis is frequently observed. The intercellular spaces are highly dilated, forming a lacunar system filled with an amorphous material, erythrocytes and involuted LTH cells. Transitional stages in the process of involution are observed in LTH cells. Luteotroph cells also form a syncytium. Twenty days after treatment the abovedescribed changes decrease in magnitude. The present findings suggest that pimozide stimulates the mechanism of synthesis and release in the luteotroph cells, an effect that is less evident with longer treatment.
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    URL: http://dx.doi.org/10.1007/BF00236084
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    Electron microscopic study of the giant cells in the olfactory bulb of labyrinth fish (Belontiidae, Perciformes) (1979)
    Springer
    Cell & tissue research 199 (1979), S. 509-517 
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    ISSN: 1432-0878
    Keywords: Olfactory bulb ; Giant cells ; Neurosecretion ; Electron microscopy ; Labyrinth fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The giant cells in the olfactory bulb of labyrinth fish, most likely belonging to the nervus terminalis, show ultrastructural features of active synthesis of secretory material. Dense core vesicles (70–100 nm in diameter), found in the perikaryon as well as in the axon, are the possible storage sites of the secretory substance. Its chemical nature is unknown. In some of these vesicles acid phosphatase is demonstrable. Large membrane-bound bodies (up to 2000 nm in diameter), either containing an electron dense matrix or debris of cytoplasmic organelles, are also acid phosphatase-positive, suggesting their lysosomal nature. Some other ultrastructural characteristics of these cells are also described.
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    URL: http://dx.doi.org/10.1007/BF00236086
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    The filum terminale of the frog spinal cord (1979)
    Springer
    Cell & tissue research 199 (1979), S. 519-528 
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    ISSN: 1432-0878
    Keywords: Filum terminale ; Spinal cord ; Glial cells ; Ultrastructure ; Frog (Rana pipiens)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The filum terminale, or terminal portion of the spinal cord, was studied in normal adult frogs (Rana pipiens) by means of light and electron microscopy. Astroglial cells are the predominant elements in this region. The rostral portion of the filum terminale consists mainly of (1) a peripheral dense ring of myelinated and some unmyelinated nerve fibers, and processes of astrocytes terminating at the subpial space; (2) an intermediate zone, in which astrocytes are the main cellular elements in addition to a few degenerated neurons; and (3) a central region where the central canal is lined by dark and light ependymal cells. In the caudal portion of the filum terminale, the amount of neuropil is greatly reduced. This region is formed mainly by astrocytic glial cells and very few neuronal elements. The central canal in the caudal portion is located ventrally and contains a lining consisting almost exclusively of dark ependymal cells.
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    Cytological changes in the pars distalis of the female rat hypophysis grafted under the kidney capsule (1979)
    Springer
    Cell & tissue research 199 (1979), S. 539-543 
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    ISSN: 1432-0878
    Keywords: Pars distalis ; Graft ; Ultrastructure ; Prolactin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intact female rats received transplants of two hypophysial partes distales under the kidney capsule. The plasma levels of prolactin were determined, and the ultrastructure of the grafted gland was studied 15, 45 and 90 days after the operation. Although prolactin levels in the three experimental groups were significantly higher than those in control rats, a decrease in prolactin level was detected in the 45-day samples. Parallel ultrastructural changes suggest that between the 45th and 90th postoperative day a process is initiated leading to hyperplasia and hypertrophy of prolactotrophs.
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    URL: http://dx.doi.org/10.1007/BF00236089
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    Maturation of secretory granules in the endosalpinx one to four days post coitum in sheep (1979)
    Springer
    Cell & tissue research 201 (1979), S. 145-158 
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    ISSN: 1432-0878
    Keywords: Ultrastructure ; Secretory granules ; Endosalpinx ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of granules in the secretory cells of the endosalpinx of 20 Merino ewes was examined on days 1, 2, 3, and 4 post coitum. Based on the different frequency of granules of different size and structure on days one to four post coitum, one can assume that the ovoid, membrane bounded secretory granules mature in five successive stages. In stage I small, electron-lucent vesicles with a finely granulated and filamentous content become apparent, initially in the neighbourhood of the Golgi complex. In stage II the granules become larger and progressively more eletron-dense by an increase of the granulated material. In stage III, the primarily granulated content forms membranes, that lie in characteristic stacks at different angles to one another, separated by electron-dense areas. This structure fragments when the granule comes to lie beneath the surface of the cell (stage IV) and opens into the lumen of the oviduct, where its content is discharged in membrane fragments or vesicles (stage V). This discharge is mainly observed shortly before the egg is transported into the uterus.
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    Ultrastructural responses of pancreatic β cells to metabolic alkalosis (1979)
    Springer
    Cell & tissue research 201 (1979), S. 159-163 
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    ISSN: 1432-0878
    Keywords: Insulin secretion ; Acid-base changes ; Electron microscopy ; Pancreas perfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes in pancreatic β cells were studied following glucose-induced insulin secretion in vitro, at two different extracellular pH (7.4 and 7.8). The pancreata perfused at pH 7.4 exhibited a biphasic insulin response to glucose challenge together with signs of increased emiocytotic activity and numerous microtubules in the β cells. Conversely, the pancreata perfused at pH 7.8 showed a significant decrease in insulin secretion, and their β cells revealed scarce emiocytotic images and a marked increase of intracellular granulolysis. These results represent the ultrastructural correlate of the reduced insulin secretion produced by metabolic alkalosis in the perfused rat pancreas.
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    URL: http://dx.doi.org/10.1007/BF00238055
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    Fine structure of the rabbit adrenal cortex and the effects of short-term ACTH administration (1979)
    Springer
    Cell & tissue research 201 (1979), S. 165-179 
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    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Steroid release ; Rabbit ; Electron microscopy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the rabbit adrenal cortex was investigated. The parenchymal cells display the ultrastructural features of steroid-producing cells, and also contain numerous electron-dense bodies frequently located near intercellular canaliculi, which open into the subendothelial space. Short-term ACTH-administration induced a noticeable decrease in the volume of the lipid compartment in the cells of all three cortical zones and a significant increase in the volume of dense bodies in the cells of zona fasciculata and zona reticularis. The hypothesis that these dense bodies are secretory granules is discussed in the light of biochemical evidence showing that ACTH increases the concentration of both corticosterone and cortisol in the decapsulated-enucleated adrenal homogenate and does not affect the activity of two lysosome-marker enzymes (i.e., acid phosphatase and β-glucuronidase).
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    Fine structure of the rhombencephalic tela of the bullfrog, Rana catesbeiana (1979)
    Springer
    Cell & tissue research 202 (1979), S. 479-491 
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    ISSN: 1432-0878
    Keywords: Ependyma ; Ultrastructure ; Posterior tela choroidea ; Rhombencephalon ; Rana catesbeiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The posterior rhombencephalic tela choroidea of the bullfrog was examined by electron microscopy. This membrane, the pia-ependymal roof of the caudal hindbrain, contains a large central region characterized by cuboidal ependymal cells which surround sizable microscopic apertures — the interependymal pores. Ultrastructurally ependymal cells of this area are characterized by infrequent apical microvilli and cilia. They contain irregularly shaped nuclei and few cytoplasmic organelles that are largely apical in position. The most striking feature is an abundance of cytoplasmic filaments forming an extensive cytoskeleton. Laterally these cells are joined by numerous elaborate desmosomes. The majority of the ependymal cells have a basal lamina consisting of single, double, or triple laminae lying parallel to the basal plasma membrane. Several unusual specializations are seen at the margins of the interependymal pores. The ependymal cells have lateral cytoplasmic processes that form the actual border of each pore. These processes originate from the apical surface of the cell and partially enclose an elaborate network of basal lamina associated with the interependymal pores. These findings demonstrate microscopic apertures in the roof of the fourth ventricle in the bullfrog that are associated with an unusual form of supportive ependyma.
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    URL: http://dx.doi.org/10.1007/BF00220439
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    Control of the pars intermedia of the lizard, Anolis carolinensis (1979)
    Springer
    Cell & tissue research 199 (1979), S. 1-23 
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    ISSN: 1432-0878
    Keywords: Neuro-intermediate lobe ; Hypophysis ; Disconnection ; Ultrastructure ; Colour change ; Control mechanisms ; Anolis carolinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphological changes in the disconnected neuro-intermediate lobe were studied in the lizard, Anolis carolinensis from the 2nd to the 14th post-operative day using a threefold aldehyde fixative (Rodríguez, 1969). Two phases of colour change capacity were exhibited: Phase I started immediately after the transection, lasted for 6 days (mean) and was characterised by an excessive MSH release (brown skin). This phase proceeded gradually into Phase II, designated by an interruption of the MSH release (green skin). The degenerative processes and final elimination of neurons in the disconnected neural lobe propagate in a rostro-caudal direction from the transected area. The aminergic fibres (Type II) disappear within 2 days postoperatively, whereas the degeneration continues for more than 10 days in the peptidergic fibres (Type III, IV and V). The glia cells (ependyma and pituicytes) serve as very active macrophages, engulfing fragments of axons already affected by autolysis and transferring them into glial lysosomes. No apparent morphological changes occur in the shift from Phase I to II. The great majority of the secretory cells of the intermediate lobe are not affected by degenerative processes and appear to be markedly activated by the stalk transection. They exhibit numerous mitochondria, well-developed Golgi complexes forming numerous Golgi vesicles and extensive parallel cisternae of the rough endoplasmic reticulum, sometimes forming large intracisternal droplets (7 μm in diameter). Numerous pale vacuoles are seen, especially toward the intact capillaries, suggesting their coupling to the MSH release by extension of the active membrane area toward the perivascular septum. The number of these vacuoles is very markedly reduced in Phase II (no release), whereas the formation of new granules seems to proceed in early stages. The interruption of the MSH release implies a successive refilling of gradually growing secretory granules and a concomitant reduction in the development of the synthetic apparatus. Mechanisms probably involved in the control of the synthesis and release of MSH are discussed.
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    URL: http://dx.doi.org/10.1007/BF00237724
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    Ultrastructural studies on erythropoiesis in the avian thymus (1979)
    Springer
    Cell & tissue research 199 (1979), S. 37-61 
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    ISSN: 1432-0878
    Keywords: Avian thymus ; Ultrastructure ; Erythropoiesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thymus lobes from three species of birds, Quelea quelea, Passer domesticus and Sturnus vulgaris, have been examined ultrastructurally. The component cell types are compared with their counterparts in mammalian thymus glands, and found to be similar. Greater differences exist between small, intermediate and enlarged lobes of one species than exist between species. Developing erythroid cells are present in most enlarging and some enlarged glands. They appear to be developing at the expense of lymphoid cells in some birds. The origin of these cells is discussed. Cells that are possible candidates for the production of some thymic hormones are also described.
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    An ultrastructural and cytochemical study of the interaction between latex particles and the haemocytes of the wax moth Galleria mellonella in vitro (1979)
    Springer
    Cell & tissue research 199 (1979), S. 127-137 
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    ISSN: 1432-0878
    Keywords: Haemocytes ; Phagocytosis ; Lysosomes ; Acid phosphatase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The plasmatocytes are the major phagocytic blood-cell type in the haemolymph of the wax-moth, Galleria mellonella. In the present study, these cells were allowed to attach to tissue culture dishes for 1 h, rinsed and then incubated with latex beads for up to 72 h. These cells were then fixed for routine transmission electron microscopy and acid phosphatase cytochemistry. Intracellular latex particles were found in tight, ill-defined phagosomes, which were often clearly associated with the Golgi complexes of the plasmatocytes. Fusion of both primary lysosomes and multivesicular bodies with the phagosomes occasionally occurred and this resulted in the accumulation of an acid phosphatase positive reaction product around the test particles. Subsequent experiments showed that this acid phosphatase activity was mainly associated with the primary lysosomes. The results of the lysosome/latex interactions are compared with those obtained from similar studies on the digestive mechanisms in other phagocytes.
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    Spatial distribution of excitatory innervation on a muscle fiber of the lobster (Homarus americanus) (1979)
    Springer
    Cell & tissue research 199 (1979), S. 171-175 
    Details
    ISSN: 1432-0878
    Keywords: Crustaceans ; Neuromuscular synapse ; Multiterminal innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of nerve terminals from a single excitatory motor axon has been followed along a fiber from the proximal accessory flexor muscle of the lobster by thin serial sectioning at periodic intervals. The excitatory motor axon provides small axonal branches (diameter 5–12 μm) of varying lengths that travel along the surface of the muscle fiber. Each of these branches gives rise to discrete synaptic terminals which are not uniformly distributed. Individual terminals vary in length from 10–60 μm and the majority possess neuromuscular synapses. The greatest distance between synapses is slightly over 1 mm which is well within the length constant (2.6 mm) of this muscle fiber. Thus the spatial distribution of synapses is such as to ensure adequate depolarization along the entire length of the muscle fiber.
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    URL: http://dx.doi.org/10.1007/BF00237737
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    Reformation of gap and tight junctions in regenerating liver after cholestasis (1979)
    Springer
    Cell & tissue research 199 (1979), S. 257-270 
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    ISSN: 1432-0878
    Keywords: Liver ; Bile duct ligation ; Tight junctions ; Gap junctions ; Ultrastructure ; Freeze-fracturing ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphometric analysis of the alterations in interhepatocyte junctions induced by bile duct ligation revealed that after 48 h, during which time the serum bilirubin increased 6 to 8 fold, the membrane area occupied by gap junctions on the apico-lateral and medio-lateral sides decreased from 3.6% in controls to 0.02% in the ligated group. The strands of the zonulae occludentes were reduced in number and showed increased discontinuities. Within 45 min of recanalization of the common bile duct, clusters of particles appeared within and adjacent to the tight junctional areas or in the lateral hepatocyte membrane. Subsequently, the particle aggregations localized in the apico-lateral membrane areas increased in number and size becoming finally indistinguishable from those of controls within 96 h after the onset of recanalization. The zonulae occludentes also rearranged and reestablished their original structure during this period. The serum bilirubin fell to normal within 24 h of recanalization. It is concluded that metabolic and ultrastructural restitution associated with the recanalization of the ligated bile duct have no strict temporal correlation to one another. These studies provide further evidence that alterations in gap and tight junctions induced by pathological processes, e.g. during bile duct ligation, are completely reversible when regeneration occurs.
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    Marginal bundles of axoplasmic microtubules at nodes of Ranvier within muscle (1979)
    Springer
    Cell & tissue research 199 (1979), S. 281-288 
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    ISSN: 1432-0878
    Keywords: Annular microtubules ; Nodes of Ranvier ; Nerve ; Axon ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using a special albumin technique, nodes of Ranvier have been examined within frog skeletal muscle, sciatic nerve and rat and frog cerebrum. Initial segments have been examined in cerebrum of frog and rat. Microtubules usually run longitudinally through these regions, but within the bare area of the intramuscular node of Ranvier, annular or helical bundles of microtubules run in a marginal band at right angles to the more centrally placed longitudinal microtubules. These nodal bare areas show a pronounced convexity and it is suggested that the annular microtubules serve to maintain this convexity during muscle contraction.
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    Vacuolated neurons in the hypogastric ganglion of the rat (1979)
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    Cell & tissue research 199 (1979), S. 373-386 
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    ISSN: 1432-0878
    Keywords: Hypogastric ganglion (rat) ; Vacuolated neurons ; Catecholamine fluorophore ; Ultrastructure ; Testosterone ; Castration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vacuolated neurons (VN) of the main hypogastric ganglion of the male rat were studied using the formaldehyde-induced fluorescence (FIF) method for the histochemical demonstration of catecholamines. Microspectrofluorimetry was performed to identify the fluorophores and to quantify the FIF. The thiocholine method (Koelle-Gomori) was used to demonstrate acetylcholinesterase activity. The fine structure of the VN was studied using glutaraldehyde/OsO4 fixation. (1) In the untreated adult male rat VN represent only a small population of the total number of hypogastric neurons (0.8–1.2%). The vacuoles are similar to those of the VN from the corresponding female ganglion. (2) The VN are considered to be adrenergic due to the nature of their fluorophore, indicating a primary catecholamine. (3) The first VN appear in the hypogastric ganglia at the age of 7 weeks. After testosterone administration to young rats, VN are found at the age of 4 weeks. (4) The basic fine structure of the VN is similar to that of other ordinary neurons of the hypogastric ganglia. (5) The content of the vacuoles could not be identified. (6) Indications of degeneration were not observed in the VN. (7) The VN are interpreted as being a functional stage of the “short” adrenergic neurons, which are under the control of steroid hormones. (8) Fifteen months after castration, no VN could be found in the hypogastric ganglia, while their number was normal in the corresponding control animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236076
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  • 99
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    Electronic Resource
    A new morphological aspect of the brush cells of the mouse gallbladder epithelium (1979)
    Springer
    Cell & tissue research 201 (1979), S. 37-44 
    Details
    ISSN: 1432-0878
    Keywords: Brush cell ; Receptor ; Lateral microvilli ; Gallbladder ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The brush cells of the gallbladder epithelium of the mouse have microvilli not only at their luminal border but also on their lateral surface, from the level of the nucleus to the junctional complex. The lateral microvilli radiate from the brush cell in all directions, contain a core of filaments, and penetrate up to 3 μm into the adjacent cells. The microvilli in these locations display small desmosomes at their base.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238045
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  • 100
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    Electronic Resource
    Ultrastructural heterogeneity of the mesocoxal muscles of Periplaneta americana (1979)
    Springer
    Cell & tissue research 201 (1979), S. 305-314 
    Details
    ISSN: 1432-0878
    Keywords: Cockroach ; Muscle heterogeneity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies have been performed upon the posterior coxal depressor muscle (136) and a coxal branch of the main depressor group (135d′) from the mesocoxa of the cockroach, Periplaneta americana. The quantitative stereometric analyses performed have shown the latter muscle to consist of a dorsal band of fibers having 25.5% mitochondria and 13.6% sarcoplasmic reticulum (SR) and T-tubules (TTS), and a ventral group of fibers with only 4.4% mitochondria and 26.6% SR/TTS. The volume fractions characteristic of the ventral fibers of muscle 135 d′ are also typical of muscle 136.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235066
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