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  • Articles  (35)
  • Polymer and Materials Science  (21)
  • Aldosteron  (9)
  • Sarcoplasmic reticulum  (5)
  • 11
    ISSN: 1432-1440
    Keywords: Altern ; Renin ; Aldosteron ; Cortisol ; Katecholamine ; Austauschbares Natrium ; Blutvolumen ; Aging ; Plasma renin ; Plasma aldosterone ; Plasma cortisol ; Urinary catecholamines ; Blood volume ; Exchangeable sodium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Interrelations between age and plasma renin, aldosterone and cortisol levels, urinary catecholamines, plasma and blood volumes, exchangeable body sodium and blood pressure were studied in 28 young (19 to 29 years), 16 middle-aged (32 to 58 years) and 15 elderly (60 to 74 years) healthy subjects. Supine and upright plasma renin and supine aldosterone levels decreased while urinary noradrenaline excretion rate increased progressively with aging (r≥0.34;p〈0.05), with significant differences in mean values between young and elderly subjects (p〈0.02). There was also an age-related decrease in upright plasma aldosterone concentration, although this was not statistically significant. Furthermore, mean plasma cortisol concentrations increased in response to upright posture in elderly (+50%;p〈0.02), but not in young (−10%) or middle-aged (−8%) subjects. Blood pressure correlated with age (r=0.35;p〈0.05) or noradrenaline excretion rate (r=0.34) in the entire study population and with blood volume in the elderly (r=0.68), but not in the young or middle-aged study groups. There were no significant age-related differences in the body sodium/volume state, basal plasma cortisol levels or urinary adrenaline excretion rate, and plasma renin or aldosterone levels did not correlate with these parameters or with blood pressure. It is concluded that the influence of age on plasma renin or aldosterone levels, plasma cortisol responsiveness to upright posture, and urinary noradrenaline excretion should be taken into consideration, whenever these factors have to be interpreted in patients with arterial hypertension or other clinical disorders. Furthermore, these data are consistent with the possibility that in normal man increases in supine blood pressure with aging may be related at least partly to concomitant changes in free peripheral noradrenaline.
    Notes: Zusammenfassung Untersuchungen bei 28 jungen (19–29 Jahre), 16 mittel-alten (32–58 Jahre) und 15 älteren (60–74 Jahre) Normalpersonen zeigten eine mit zunehmendem Alter progressive Abnahme der Plasmareninaktivität und -aldosteronkonzentration sowie eine Zunahme der Noradrenalinexkretionsrate. Mit Ausnahme der im Stehen gemessen Plasmaaldosteronspiegel waren die Korrelationen dieser Parameter mit dem Alter (r≥0,34;p〈0.05) sowie die Unterschiede der Mittelwerte zwischen jungen und älteren Personen (p〈0,02) signifikant. Die Plasmacortisolkonzentration blieb beim Aufstehen bei jungen und mittel-alten Personen im Mittel unverändert (−10 und −8%), stieg jedoch bei älteren Menschen um 50% an (p〈0,02). Der Blutdruck korrelierte (p〈0,05) bei Analyse der gesamten Studienpopulation mit dem Alter (r=0,35) und der Noradrenalinexkretionsrate (r=0,34), bei den älteren Personen fand sich auch eine signifikante Beziehung zum Blutvolumen (r=0,68). Austauschbares Körpernatrium, Plasma- und Blutvolumina und Adrenalinexkretionsrate zeigten keine signifikanten altersbezogenen Variationen. Plasmarenin- und -aldosteronspiegel korrelierten weder mit diesen letzteren Parametern noch mit dem Blutdruck. Es wird gefolgert, daß der Einfluß des Alters auf Plasmarenin- und -aldosteronwerte, das freie periphere Noradrenalin und die Stimulierbarkeit von Plasmacortisol durch Orthostase in Betracht gezogen werden sollte, wenn immer diese Faktoren bei Patienten mit arterieller Hypertonie oder anderen klinischen Störungen interpretiert werden müssen. Diese Resultate sind außerdem mit der Möglichkeit vereinbar, daß die altersbezogene Zunahme des Liegendblutdrucks beim normalen Menschen zumindest teilweise auf dem parallelen Anstieg des freien peripheren Noradrenalins beruhen könnte.
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  • 12
    ISSN: 1432-1440
    Keywords: Aldosterone ; cortisol ; sodium ; potassium ; hemodialysis ; Aldosteron ; Cortisol ; Natrium ; Kalium ; Hämodialyse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Plasmaaldosteron, Plasmacortisol und die Serumkonzentrationen von Kalium und Natrium wurden bei 5 nierenlosen Patienten vor und in kurzen Zeitabständen bis zu 180 min nach Beendigung der Hämodialyse gemessen. Unter Hämodialyse stieg das Plasmaaldosteron bei 4 der 5 Patienten an, während bei allen Patienten Cortisol, Kalium und Natrium abfielen. Nur bei einem Patienten ließ sich unter Hämodialyse ein Abfall des Aldosterons nachweisen. Nach Beendigung der Hämodialyse kam es über den untersuchten Zeitraum bei 3 der 5 Patienten zu cinem fast kontinuierlichen Abfall des Plasmaaldosterons, während die beiden anderen Patienten Sekretionsepisoden des Aldosterons mit spontanen Anstiegen und anschließendem Abfall der Hormonkonzentration zeigten. Bei allen Patienten stieg nach Hämodialyse das Serumkalium rasch wieder an, während nur geringgradige Veränderungen des Serumnatriums nachweisbar waren. Plasmacortisol zeigte während der Beobachtungsperiode typische tageszeitliche Schwankungen. Wir nehmen an, daß ein noch unbekannter Faktor für den Anstieg des Plasmaaldosterons unter Hämodialyse verantwortlich ist. Einiges spricht dafür, daß über den nach Hämodialyse beobachteten Zeitraum die intracelluläre Kaliumkonzentration und nicht das Serumkalium die Aldosteronsekretion beeinflußt. Dies würde den bei 3 der 5 Patienten scheinbar paradoxen Abfall des Aldosterons bei steigendem Serumkalium erklären.
    Notes: Summary Plasma aldosterone, plasma cortisol and the serum concentrations of sodium and potassium were determined in 5 anephric patients before and at short time intervals up to 180 minutes after hemodialysis. Plasma aldosterone increased in 4 of 5 patients during hemodialysis while in all patients plasma cortisol, sodium and potassium decreased. Only one patient showed a fall in aldosterone during hemodialysis. After hemodialysis plasma aldosterone gradually decreased over a period of 3 hours in 3 of 5 patients, whereas the remaining two patients showed typical secretory episodes of aldosterone. In each patient serum potassium rapidly increased while serum sodium showed only minor variations. Plasma cortisol followed the normal circadian rhythm. We suggest that a still unknown factor had caused the observed increases in plasma aldosterone during hemodialysis. There are reasons to believe that over the period observed after hemodialysis the intracellular potassium concentration and not serum potassium levels has influenced adrenal aldosterone release. This would explain the paradoxical decrease in plasma aldosterone in 3 of the 5 patients while serum potassium increased.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 56 (1978), S. 229-234 
    ISSN: 1432-1440
    Keywords: Aldosteron ; Renin ; Cortisol ; Diabetes mellitus ; Hypoaldosteronismus ; Hyperkaliämie ; Aldosterone ; Renin ; Cortisol ; Diabetes ; Hypoaldosteronism ; Hyperkalemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary In three patients with diabetes and hyporeninemic hypoaldosteronism changes in renin activity, plasma aldosterone and cortisol were examined under various conditions: orthostasis and intravenous furosemide, infusion of synthetic β1–24 ACTH on two consecutive days and diurnal variations in basal hormone fluctuations. Each patient showed unmeasurably low renin activity unresponsive to orthostasis and intravenous furosemide while plasma aldosterone was below normal range. Under ACTH-infusion only marked increases in aldosterone were observed in one patient whereas cortisol responded normally in all diabetics tested. Analysis of diurnal night day fluctuations (20.00–8.00) in plasma aldosterone and cortisol revealed a close and statistically significant relationship between both hormones in each of the three patients (p〈0.05–〈0.001). Variations in plasma aldosterone thus were mediated through changes in endogenous pituitary ACTH. Compared with normal controls however, diurnal aldosterone curves were set at a lower level. Our results demonstrate that a reduced sensitivity of the adrenal gland to ACTH is not responsible for the observed subnormal plasma aldosterone levels in these patients. Therefore, the lack of circulating angiotensin II seems to be the causative reason of hypoaldosteronism. The exact mechanism of undetectable renin activity in these patients remains unknown.
    Notes: Zusammenfassung Bei drei Patienten mit Diabetes mellitus und hyporeninämischem Hypoaldosteronismus wurden Veränderungen der Plasmareninaktivität, des Plasmaaldosteron- und Plasmacortisolspiegels unter folgenden Bedingungen geprüft: Orthostase und intravenöse Furosemidapplikation, Infusion von synthetischem β1–24 ACTH an zwei aufeinanderfolgenden Tagen, Tag-Nacht-Rhythmus der basalen Hormonplasmaspiegel. Alle Patienten zeigten eine nicht meßbare und durch Orthostase und Furosemid nicht stimulierbare Reninaktivität. Gleichzeitig wurden subnormale Aldosteronplasmakonzentrationen gemessen. Unter ACTH-Infusion zeigte nur ein Patient einen deutlichen Anstieg des Plasmaaldosterons, während das Plasmacortisol in allen drei Fällen normal stimulierbar war. Die statistische Analyse der Tag-Nacht-Schwankungen von Plasmaaldosteron und Plasmacortisol zeigte in jedem der Fälle eine enge und statistisch signifikante Beziehung zwischen beiden Hormonen (p〈0,05–〈0,001). Es ist somit anzunehmen, daß Schwankungen des Plasmaaldosterons durch Veränderungen der hypophysären ACTH-Ausschüttung verursacht wurden. Jedoch war im Vergleich zu Normalpersonen die Rhythmik des basalen Plasmaaldosterons auf einem tieferen Niveau eingestellt. Unsere Ergebnisse lassen den Schluß zu, daß bei diesen Patienten nicht eine verminderte Sensitivität der Nebennierenrinde auf ACTH für die beobachteten subnormalen Aldosteronspiegel verantwortlich ist. Ursache für den Hypoaldosteronismus scheint somit der Mangel an zirkulierendem Angiotensin II zu sein. Der genaue Mechanismus der nicht meßbaren Reninaktivität bei diesem Patienten bleibt unbekannt.
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  • 14
    ISSN: 1432-2013
    Keywords: Heart function ; Postnatal development ; Thyroid hormones ; Sarcolemma ; Sarcoplasmic reticulum ; Ca2+ transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Newborn rats were rendered hyperthyroid (daily subcutaneous injections of L-triiodothyronine, 10 μg 100 g−1 body weight) or hypothyroid (0.05% 6-n-propyl-2-thiouracil in drinking water to nursing mothers) during the first 3 weeks of postnatal life. Compared with the euthyroid group, hyperthyroidism resulted in: (1) cardiac enlargement with right ventricular preponderance, (2) increased cardiac contractile function, (3) increased Ca2+ uptake by the sarcoplasmic reticulum (SR), (4) decreased sensitivity to the negative inotropic effect of verapamil and (5) greater inhibition of contractile function by ryanodine. Hypothyroidism generally resulted in opposite changes. The data suggest that the development of the heart and its contractile function during early postnatal life depends on the plasma level of thyroid hormones. In particular, the relative contribution of the SR and sarcolemmal Ca2+ transport to the control of cardiac contractility seems to be markedly affected by altered thyroid states. The postnatal maturation of the SR function is accelerated in hyperthyroidism but retarded in hypothyroidism. Consequently, hyperthyroid hearts appear to be less dependent and hypothyroid ones more dependent on trans-sarcolemmal Ca2+ fluxes when compared with age-matched euthyroid animals.
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  • 15
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The porous copolymer films of N-methacryloyl-L-alanine methyl ester and diethyleneglycol-bis-allylcarbonate (diallyl oxydiethylene dicarbonate) were hydrolyzed with 1 M NaOH solution for 40 min at 25°C. The pores of the films showed pH response in diameter. The pore diameter of 3,7 μm in the buffer solution of pH 3 was closed completely at pH 5.
    Additional Material: 4 Ill.
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  • 16
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Flow control for small metering pumps with continuous and pulsating flow. Metering of small flows with high discharge pressure is performed mainly by displacement metering pumps. The necessary mass-flow control shows problems with pulsating piston- or diaphragm metering pumps. A survey explains the presently available continuous and discountinuous methods of mass- and volume flow control. Special investigations have been performed with differential scales and mass flow meters based on the Coriolis- and the thermal principle. The differential weighing method shows good accuracy down to minimum mass flows of 0.1 kg/h. This method is expensive and requires vibration protected installation. The Coriolis flow meter, applicable over a similar range, precisely integrates the pulsating signal, but requires damping or signal averaging for regulation purposes. Thermal flow meters prove rather sensitive to temperature fluctuations. Under stable conditions and with proper calibration this principle may be applied to flows even below 0.1 kg/h.
    Additional Material: 26 Ill.
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  • 17
    ISSN: 0009-286X
    Keywords: Dosieren ; Schüttguttechnik ; Schneckendosierer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
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  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 65 (1993), S. 1088-1090 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 67 (1995), S. 1184-1185 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 67 (1995), S. 1185-1186 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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