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  • Ultrastructure  (5)
  • hypertension  (5)
  • Springer  (10)
  • PANGAEA
  • 1980-1984  (10)
  • 1983  (10)
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Verlag/Herausgeber
  • Springer  (10)
  • PANGAEA
Erscheinungszeitraum
  • 1980-1984  (10)
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 116 (1983), S. 1-13 
    ISSN: 1615-6102
    Schlagwort(e): Cuticle ; Peristomatal transpiration ; Stomata ; Ultrastructure ; Funaria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Cuticle and pore development in the guard cells ofFunaria were investigated with the electron microscope. Pore cuticle formation is simultaneous with the creation of the pore itself. The morphology of the pore cuticle is unlike that of any cuticle described in the literature. It has many lamellae which are penetrated by electron dense fibrils. Three different cuticular morphologies exist from the pore to the subsidiary cell walls. The cuticles on the pore and outer walls contain fibrils that sometimes reach to the surface. The subsidiary cell cuticle lacks fibrils altogether. It is hypothesized that (1) cuticularization of the middle lamella contributes to ventral wall separation and (2) differences in extent of cuticular fibrils are related to greater water loss from stomata than from subsidiary cells (peristomatal transpiration).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 228 (1983), S. 389-403 
    ISSN: 1432-0878
    Schlagwort(e): Lymph node, avian ; Ultrastructure ; Macrophages ; Phagocytic capacity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The structure of the avian lymph node (ALN) is characterized by a thin capsule, thin lymphoreticular cords, and an absence of trabeculae. It is not possible to subdivide the ALN into cortex, paracortex and medulla, or to subdivide the system of sinuses into marginal, trabecular and medullary divisions. The lymphoreticular cords contain avian germinal centers (AGC) with B-lymphocytes and the area of T-lymphocytes. Postcapillary venules are responsible for the recirculation of lymphocytes. Sinus reticular cells do not exist in the ALN, but free macrophages are present. The phagocytic capacity of the macrophages was determined by injection of vital dyes (India ink, Berlin blue) and inoculation with Candida cells. Macrophages filled with markers migrate from the lymph sinuses into the lymphoreticular cords and further into the AGC. The mobility of the macrophages is remarkably lower after phagocytosis of Candida cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 24 (1983), S. 15-19 
    ISSN: 1432-1041
    Schlagwort(e): hypertension ; mianserin ; clonidine ; methyldopa ; depression ; α2 receptors ; interaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The concurrent administration of tricyclic antidepressants has been shown in man to result in a clinically significant impairment of the antihypertensive effect of clonidine. This interaction is thought to be related to competition for central α2 receptors where clonidine acts as an agonist and the tricyclics act as antagonists. Although it seems to cause less cardiovascular effects than tricyclic antidepressants, the tetracyclic antidepressant, mianserin also has been reported to be an α receptor antagonist and may, therefore, also interfere with the antihypertensive activity of centrally-acting drugs. This study investigates the effects of acute and chronic mianserin administration in patients with essential hypertension established on long term treatment with either clonidine or methyldopa. The first dose of mianserin was not associated with an increase in blood pressure and during a further two weeks of mianserin therapy there were no significant alterations in blood pressure, supine or erect. Similarly, mianserin did not alter heart rate either after acute or after chronic administration. Mianserin itself had a sedative effect but there was no interference with the sedation attributable to clonidine or methyldopa. Mianserin caused no reduction in salivary flow and did not influence the reduced saliva production caused by clonidine. Both clonidine and methyldopa are associated with a reduction in sympathetic outflow but there was no evidence in this study of any further change in plasma noradrenaline or 24 h urinary catecholamine excretion. This study demonstrates that if mianserin is given acutely or chronically, it does not interfere with the effects of the centrally acting antihypertensive drugs, clonidine and methyldopa. Mianserin may therefore be a suitable antidepressant for patients receiving these antihypertensive agents if drug treatment for depression is indicated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 463-466 
    ISSN: 1432-1041
    Schlagwort(e): guanfacine ; hypertension ; phenobarbital ; withdrawal syndrome ; enzyme induction ; pharmacokinetics ; renal insufficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The unusual observation of a withdrawal syndrome due to guanfacine in a hypertensive patient with chronic renal failure led to a study of the kinetics of the drug in this patient. The principal pharmacokinetic parameters of guanfacine were greatly altered, with extended biotransformation and a decrease in the half-life compared to the values observed in other cases of severe renal insufficiency. Associated treatment with phenobarbital had had a considerable effect, as shown by the results of a further kinetic study 2 months after withdrawal of the phenobarbital. The findings then were in good agreement with reference values which strongly suggests a consequence of the enzyme inducing effect of phenobarbital. Advice about the dosage regimen in such cases is given.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 481-490 
    ISSN: 1432-1041
    Schlagwort(e): propranolol ; pharmacokinetics ; pregnancy ; hypertension ; naphthoxylactic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of propranolol (P) and its major metabolites, propranolol glucuronide (PGLUC), 4-hydroxypropranolol (4OHP), 4-hydroxypropranolol glucuronide (4OHPGLUC) and naphthoxylactic acid (NLA), (Walle et al. 1972) were determined, whenever possible, in the first, second and third trimesters of pregnancy in thirteen patients and also when these patients were at least three months post-partum. No correlations were found between the mean arterial blood pressure (post-therapy) or the fall in blood pressure as a result of the P therapy (p〉 〉0.05) and P dose, peak P plasma concentrations, peak 4-hydroxypropranolol (4OHP) plasma concentrations or peak (P plus 4OHP) plasma concentrations. However, a positive nonlinear relationship was found between the daily P dose (independent variable) and peak P plasma concentrations over the daily dose range 30–160 mg/day. The elimination half-lives of NLA for patients in the third trimester of pregnancy were significantly shorter (p=0.072, df=13) than those when the patients were at least three months post-partum. Also, the areas under the plasma level-time curves of NLA were significantly less (p〈0.05, df=13) for patients in the third trimester of pregnancy than when these patients were at least three months post-partum. The results of this study indicate that the pharmacokinetics of P, PGLUC, 4OHP and 4OHPGLUC are not significantly altered by pregnancy. However, the kinetics of NLA do appear to be altered. The formation of NLA by N-dealkylation of P and further oxidation, appears to be competitively inhibited by unidentified substances, perhaps endogenous steroids, especially in the third trimester when compared to at least three months post-partum.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 25 (1983), S. 571-575 
    ISSN: 1432-1041
    Schlagwort(e): beta-blocker ; felodipine ; calcium antagonist ; hypertension ; vasodilator ; side effects ; plasma levels ; metoprolol ; propranolol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In a double-blind, cross-over trial, 10 men with primary hypertension, not adequately controlled with a β-blocker alone, were also given felodipine or placebo for periods of one week. Placebo was administered single-blind for 2 weeks and 1 week, respectively, before randomization and between treatments. The dose of felodipine ranged from 6.25 mg to 25 mg. The addition of felodipine resulted in a pronounced (20%), statistically significant reduction in blood pressure (BP) and a small but significant increase in heart rate (HR). The effects were seen within 1–2 h and were maximal after 3–4 h. During steady state treatment the duration of BP reduction was at least 12 h. No orthostatic reaction was seen. There was a significant correlation between the plasma concentration of felodipine and change in BP. The most frequently reported side-effects were headache and ankle oedema, the latter probably being due to pronounced pre-capillary vasodilatation. There was no weight increase and thus no indication of general water retention. No clinically significant change in laboratory variables and no influence on the P-Q time were seen. Thus, felodipine in combination with a β-blocker seems to be a useful addition to the treatment of hypertensive patients whose BP is not adequately controlled with a β-blocker alone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1432-1041
    Schlagwort(e): furosemide ; hypertension ; plasma renin activity ; plasma adrenaline ; plasma noradrenaline ; body fluid loss ; diuretic response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary To evaluate the role of adrenergic mechanisms in the acute response of renin to furosemide, plasma renin activity (PRA) and plasma catecholamine concentrations were measured for 3 h after i.v. administration of furosemide 1 mg/kg to 8 patients with mild essential hypertension. Furosemide induced a prompt and long-lasting increase in renin, with PRA more than doubled at all times. The increase in PRA within the first 30 min paralleled the peak increases in urinary water and sodium flow rates, and significant decreases in plasma volume and central venous pressure. There was no change in plasma catecholamine concentrations. Plasma noradrenaline was increased significantly at 60 min and adrenaline at 90 min, once furosemide had induced a marked loss of body-fluid and ∼65% decrease in central venous pressure. Both catecholamines remained elevated until the end of the study, whereas urinary water and sodium flow rates had returned to their pre-treatment values by 150 min. Mean blood pressure was essentially unchanged throughout the study, whereas heart rate increased significantly after 90 min. The findings suggest that in mildly hypertensive patients adrenergic mechanisms are not involved in the initial renin response to furosemide, but they come into play later, probably as a result of reflex sympathetic activation triggered by marked volume depletion.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 71 (1983), S. 147-153 
    ISSN: 1573-5036
    Schlagwort(e): Cortex ; Endodermis ; Picea sitchensis ; Tilia cordata ; Transfer cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The endodermis of bothTilia cordata andPicae citchensis progressess through 3 characteristic phases of development. These developments are delayed somewhat in the xylem pole endodermis ofT. cordata, while inP. sitchensis 3–5 passage cells are found. The cortex ofT. cordata is characterised by very thick walls, while that ofP. sitchensis is characterised by a thick walled layer just outside the endodermis and by 2–3 outer layers of transfer cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    ISSN: 1432-0878
    Schlagwort(e): Corpus luteum ; Ultrastructure ; Secretory granules ; Hormones ; Quantitative study
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The granulosa luteal cells of the sheep corpus luteum secrete their hormonal products by exocytosis of granules. Electron micrographs of randomly selected granulosa cells from nine corpora lutea at day 10 of the oestrous cycle were examined to obtain the cellular density of these granules. From the area of the cell, calculated using an x -y digitiser, and the number of granules observed, the number of intracellular secretory granules per μm3 of luteal cell cytoplasm was calculated. There was a large variation in the number of granules per cell within the same corpus luteum and between corpora lutea taken at the same stage of the cycle. The number of intracellular granules in nine corpora lutea varied from 2.12±1.05 granules per μm3 (x, SD, n = 30) cells to 0.36±0.18 granules per μm3 ( x, SD, n = 26). These morphological data suggest that the variation in granule synthesis in individual cells may contribute to the variation in hormone content of corpora lutea at the same stage of the cycle, and the episodic release of hormone into the plasma.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    ISSN: 1432-0878
    Schlagwort(e): Sea star ; Development ; Cuticle ; Extracellular materials ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of conspicuous extracellular materials during the life history of a sea star (Patiria miniata) is described. The outer surface of the developing sea star is covered by two morphologically different cuticles that appear sequentially during ontogeny. The primary cuticle, which is about 120 nm thick and two-layered, is present from mid-blastula through the end of the larval stage. The secondary cuticle, which is about 1 μm thick and three-layered, first appears on the epidermis of the rudiment region of the larva and, after metamorphosis, covers the entire epidermis of the juvenile and adult stages. During ontogeny, there are only two conspicuous gut cuticles: the first lines the newly invaginated archenteron at the start of the gastrula stage, and the second lines the esophagus during the larval stage. A blastocoelic basal lamina first appears at mid-blastula and persists as subectodermal and subendodermal basal laminae. Ruthenium red-positive granules are detectable between the lateral surfaces of adjacent ectodermal cells during part of the gastrula stage; this transient intercellular material may possibly aid in lateral adhesion between cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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