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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 61 (1983), S. 343-347 
    ISSN: 1432-1440
    Keywords: Captopril ; Aortic insufficiency ; Mitral insufficiency ; Regurgitant fraction ; Coronary blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to evaluate the acute effects of pharmacological blockade of the renin-angiotensinogen system in patients with chronic left ventricular volume overload, 50 mg of the converting enzyme inhibitor captopril were administered to 4 patients with aortic insufficiency and 5 patients with mitral regurgitation. Mean aortic pressure decreased from 108±17 to 89±18 mmHg (P〈0.001) and systemic vascular resistance decreased from 2,300±1,087 to 1,540±547 dyn s cm−5 (p〈0.01). Left ventricular filling pressures decreased significantly. This resulted in an increase in cardiac index from 2.6±0.8 to 2.9±0.7 1/min/m2 (p〈0.001) and an increase in the forward stroke volume index from 31±7 to 37±7 ml/m2 (p〈0.001). Left ventricular end-diastolic and end-systolic volumes decreased significantly (p〈0.05). No changes in left ventricular ejection fractions and heart rate were observed. Regurgitant stroke volume was reduced from 58±27 to 32±9 ml/m2 (p〈0.01) and the regurgitant fraction from 64±13 to 46±8% (p〈0.001). Coronary sinus blood flow decreased from 174±57 to 144±58 ml/min (p〈0.05); coronary vascular resistance remained constant. Myocardial oxygen consumption was reduced from 26±11 to 21±12 mlO2/min (p〈0.05). Captopril, therefore, has benefical hemodynamic effects in patients with chronic left ventricular volume overload due to aortic or mitral incompetence. Cardiac performance is increased at reduced metabolic costs.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Research in experimental medicine 158 (1972), S. 211-218 
    ISSN: 1433-8580
    Keywords: Hypothermic kidney preservation ; Lactate/pyruvate ratio ; pH ; Oxygen tension ; Exchanging the perfusate ; Hypotherme Nierenkonservierung ; Lactat/Pyruvat-Quotient ; pH ; Sauerstoffspannung ; Austausch des Perfusates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Hundenieren wurden bis zu 72 Std hypotherm mit Hundebzw. Humanplasma perfundiert und anschließend reimplantiert. In regelmäßigen Abständen wurden Perfusatproben entnommen und Lactat und Pyruvat gemessen. In allen Versuchen konnte ein charakteristischer Verlauf des Lactat/Pyruvat-Quotienten beobachtet werden, der nicht mit der Vitalität der Nieren korrelierte: einem Abfall des Quotienten in den ersten 20 Std der Perfusion folgte ein allmählicher Anstieg. Nieren, die mit ungenügenden Sauerstoffspannungen (pO2 unter 80 mm Hg) perfundiert worden waren, zeigten hohe Quotienten. Außerdem wurde die pH-Abhängigkeit des Lactat/Pyruvat-Quotienten geprüft. Sauerstoffspannungen zwischen 140 und 400 mm Hg und ein pH zwischen 7,0 und 7,8 beeinflußten nicht die Vitalität der Nieren. Der Anstieg des Lactat/Pyruvat-Quotienten nach 20–24 Std wird mit der Anhäufung von Toxinen im Perfusat erklärt; es wird vorgeschlagen, das Perfusat zu diesem Zeitpunkt auszuwechseln, um die Konservierungsergebnisse zu verbessern.
    Notes: Summary Dog kidneys were hypothermic perfused with canine or human plasma up to 72 hrs and then transplanted. Samples were taken regularly from the perfusate and lactate and pyruvate were measured. A characteristic behaviour of the lactate/pyruvate ratio, not corresponding with the viability of the kidneys, was seen in all experiments: after decreasing in the first 20 hrs of perfusion the lactate/pyruvate quotient gradually rose. Kidneys perfused insufficiently with oxygen (pO2 less than 80 mm Hg) showed high quotients. Besides the lactate/ pyruvate ratio was tested depending on the pH. Varying the oxygen tensions between 140 and 400 mm Hg and the pH between 7.0 and 7.8 didn't influence the viability of the kidneys. The rising of the lactate/pyruvate ratio after 20–24 hrs is explained with the accumulation of toxic products in the perfusate; exchanging the perfusate at this time is proposed to improve the results of kidney preservation.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2013
    Keywords: Glomerulo-Tubular Balance ; Reabsorptive Capacity ; Variations of GFR ; Renal Artery Constriction ; Glomerulo-tubuläre Balance ; Resorptionskapazität ; Filtravariationen ; Constriction der Nierenarterie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present study it is demonstrated that reabsorptive functions of the proximal tubule during partial renal artery clamping display significant differences when compared to spontaneous GFR variations. During moderate clamping fractional fluid reabsorption was 69.8% and fell during severe clamping to 55.2%. Proximal tubular passage time increased progressively with the degree of clamping. This indicates that radius does not change as a function of GFR, a finding supported by microphotography of the renal surface. During moderate arterial clamping proximal reabsorptive rate was correlated to the tubular cross-sectional area, but in the face of severe clamping this relationship was abolished. We conclude, therefore, that mechanisms other than tubular geometry participate in regulating proximal tubular reabsorption, when GFR is altered by arterial constriction.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 304 (1968), S. 57-68 
    ISSN: 1432-2013
    Keywords: Renal Autoregulation ; Dog Kidney Micropuncture ; Proximal Tubular Function ; Hypotension ; Renale Autoregulation ; Mikropunktion an Hundenieren ; Proximale Tubulusfunktion ; Hypotension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Micropuncture studies were carried out on the dog kidney in order to delineate the response of micropuncture parameters to changes in blood pressure within and below the autoregulatory range. By the use of chloralose anaesthesia and carotid sinus denervation elevations in systemic blood pressure were induced, while the use of Regitine permitted the induction of lower BP levels both in the lower part of the autoregulatory range and to frankly hypotensive levels. The results indicate a constancy of intratubular function (TF/P inulin, transit time, single nephron GFR, intratubular pressure) so long as blood pressure remained within the autoregulatory range, supporting the concept of a preglomerular site for autoregulation. During hypotension the single nephron GFR decreased, the transit time was prolonged, but the end proximalTF/P inulin did not change significantly. These changes in tubular function corresponded to a fall in total GFR, RBF, and filtration fraction. The fall in single nephron GFR was greater than the corresponding fall in total GFR suggesting that during hypotension the filtrate of the punctured superficial nephrons is less well protected than that of other nephrons in the dog kidney.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-2013
    Keywords: Renal Transport ; Proximal Glomerulo-Tubular Balance ; Lateral Net Flux ; Variations of GFR ; Tubular Diameter ; Renaler Transport ; Proximale glomerulo-tubuläre Balance ; Lateraler Nettofluß ; GFR-Variationen ; Tubulärer Durchmesser
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In rats with hereditary Diabetes insipidus (Brattleboro strain) proximal fluid reabsorption was studied during spontaneous variations of GFR. Independent of kidney weight and arterial blood pressure total kidney GFR varied between 0.35 ml/min×gKW and 1.8 ml/min×gKW, while single nephron filtrate showed a variation between 18 nl/min×gKW and 66 nl/min×gKW. End-proximal TF/P inulin of 78 fluid samples did not correlate with filtration rate and averaged 2.38±0.55 S.D. Also, proximal transit time was independent of filtration rate with a mean of 9.7 sec±1.1 S.D. These results imply a direct correlation between mean luminal radius and filtration rate, which was demonstrated by microphotography of the renal surface. Our data show that complete glomerulo-tubular balance in the proximal tubule exists during spontaneous variations of glomerular filtration rate. In support of the hypothesis ofGertz [4,6] the lateral net fluid flux was found to be linearly dependent upon tubular surface area. In addition, intratubular volume changed in direct proportion to single nephron filtrate. The present results are interpreted to further strengthen the assumption of a critical influence of tubular geometry on proximal fluid reabsorption during spontaneous variations of GFR.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2013
    Keywords: Hereditary Diabetes Insipidus ; Proximal Convolution ; Loops of Henle ; ADH ; Hereditärer Diabetes Insipidus ; Proximales Konvolut ; Henle'sche Schleife ; ADH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Micropuncture studies were carried out on rats with hereditary hypothalamic diabetes insipidus, in order to measure net sodium and water reabsorption in proximal convolutions and short loops of Henle during water diuresis and ADH-induced antidiuresis. Intravenous infusion of 0.15 mU ADH per minute reduced urine flow from 74.5 μl per kidney per minute to 10.8 μl, and increased urine osmolality from 117 to 605 mOsm/kg. These changes could be reversed by stopping ADH. ADH did not alter the fractional reabsorption of fluid or the reabsorptive capacity for sodium in the proximal tubules. Nor did it change glomerular filtration rates of single superficial nephrons or of the entire kidney. Fractional reabsorption of the glomerular filtrate up to the early distal convolution was significantly higher (82.0%) in water diuresis than in antidiuresis (74.4%). Since this reabsorption remained unchanged in the proximal convolutions, the decreased reabsorption during antidiuresis must have occurred in the short loops. Fractional reabsorption of sodium up to the early distal tubule was essentially identical during water diuresis and antidiuresis, indicating that ADH does not enhance urinary concentration by increasing the reabsorption of sodium from short loops.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 304 (1968), S. 365-375 
    ISSN: 1432-2013
    Keywords: Dog Kidney Micropuncture ; Glomerulo-Tubular Balance ; Proximal Tubular Function ; Ethacrynic Acid ; Mikropunktion an Hundenieren ; Glomerulo-tubuläre Balance ; Proximale Tubulusfunktion ; Ethacrynsäure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Micropuncture studies have been carried out on the dog kidney in order to evaluate the proximal tubular response in different experimental settings. When total and single nephron GFR varied spontaneously, a constancy of fractional reabsorption was observed. When GFR was drastically reduced following regitine-induced hypotension no significant difference in late proximal fractional reabsorption was noted when compared to controls, but lateral water flux and reabsorptive capacity fell markedly. Finally, during ethacrynic acid administration late proximal TF/P inulin remained constant, transit time was prolonged, and tubular radius and intratubular pressure increased. The lateral water flux was slightly reduced and reabsorptive capacity showed a moderate decrease. These studies have provided normal values for the reabsorptive characteristics of the canine proximal tubule (radius, transit time, intratubular pressure, lateral water flux, and reabsorptive capacity) and indicate that, under control conditions and during hypotension and diuretic administration, the dog and the rat have similar proximal tubular responses.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 15 (1954), S. 112-116 
    ISSN: 1432-0738
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 60 (1982), S. 107-113 
    ISSN: 1432-1440
    Keywords: Heart failure ; Angiotensin blockade ; Vasodilation ; Herzinsuffizienz ; Angiotensinhemmer ; Vasodilatation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Captopril (Lopirin Squibb, von Heyden) ein Hemmer des Angiotensin-Converting-Enzyms blockiert bei herzinsuffizienten Patienten, die durch Angiotensin II vermittelte Vasokonstriktion und Aldosteron-Stimulation. Daraus resultiert eine hochsignifikante Reduktion des kardialen Preloads und des Afterloads. Dieser Effekt führt zu einem Anstieg des Herzzeitvolumens und zum Druckabfall im Lungenkreislauf. Captopril vereinigt damit die Wirkung von arteriellen und venösen Gefäßerweiterern und entspricht in seinem vasodilatierenden Effekt etwa dem des Nitroprussid Natrium. Einheitliche Dosierungsrichtlinien für herzinsuffiziente Patienten liegen noch nicht vor. Die bisher verwendeten Dosierungen schwanken zwischen 3 × 12,5 mg täglich und 3 × 150 mg täglich. Eine Tachyphylaxie bzw. Toleranzentwicklung unter Captopril wird nicht beschrieben. Sowohl in Akutuntersuchungen als auch bei Langzeittherapie bis zu einem Jahr führt Captopril bei Patienten mit schwerer Herzinsuffizienz zu einer deutlichen Verbesserung der Hämodynamik und des klinischen Schweregrades der Herzinsuffizienz, unabhängig von deren Ätiologie. Unter den Nebenwirkungen ist besonders auf das Auftreten einer Proteinurie, Leukopenie und Verschlechterung der Nierenfunktion zu achten. Unter den leichteren dosisabhängigen Nebenwirkungen werden Geschmacksveränderungen, Hauterscheinungen, Hypotonie und orthostatische Beschwerden beschrieben. Nach den bislang vorliegenden Erfahrungen stellt Captopril eine Bereicherung für die Vasodilatantientherapie der schweren Herzinsuffizienz dar. Ebenso wie die anderen Gefäßerweiterer ersetzt Captopril bei diesen Patienten nicht die Basistherapie mit Diuretika und Digitalis. Vielmehr stellt es eine wichtige additive Therapie in Kombination mit diesen Präparaten dar.
    Notes: Summary Captopril (Lopirin, Squibb, von Heyden) is an inhibitor of the angiotensin-I converting enzyme. In congestive heart failure angiotensin mediated vasoconstriction and aldosterone secretion is reversed by captopril. Both effects of captopril induce reduction of cardiac preload and afterload. The clinical state of patients with congestive heart failure therefore improves since cardiac output increases and pulmonary pressures decrease. Captopril acts orally and the dosage used for the treatment of congestive heart failure ranges from 50 to 150 mg daily. After oral ingestion of a single dose the maximum haemodynamic effect is observed after 45–90 min. No tolerance induction or tachyphylaxis has been observed during maintenance therapy over a period of 18 months. There are some reversible adverse reactions like pruritus, skin rash and partial or complete taste loss which are dose related. Serious side effects include leucopenia, agranulocytosis, renal failure and membranous glomerulonephritis. Therefore regular urinary and blood analysis is necessary during captopril therapy.
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  • 10
    ISSN: 1432-1440
    Keywords: Hypogonadismus ; Androgene ; Gonadotropine ; Dauerdialyse ; Testicular insufficiency ; Testosterone ; Gonadotrophins ; Dialysis treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 13 männliche Dialysepatienten im Alter von 25–65 Jahren erhielten Gonadotropine (HCG-Primogonly®) zunächst 2 × wöchentlich 2000 IE und nach einer 2–3-wöchigen Therapiepause 1 × wöchentlich 2000 IE. Vor HCG und während der 4monatigen Behandlung wurden in 1- bis 2wöchentlichen Abständen Testosteron-, Dihydrotestosteron-, Androstan-Diol-, LH- und FSH-Spiegel radioimmunologisch bestimmt. Vor HCG-Zufuhr waren die Testosteronspiegel stark erniedrigt, die Testosteronmetaboliten (DHT und A-Diol) sowie die Gonadotropine (FSH und LH) im Plasma erhöht. Nach HCG kam es zu einem verzögerten und inadäquaten Anstieg der Testosteronspiegel auf Normalwerte. In der Therapiepause fielen die Werte sofort auf die Ausgangswerte ab. Mit einer reduzierten Dosis (2. Therapiephase) war es nicht möglich, eine anhaltende Erhöhung der Testosteronspiegel zu erzielen. DHT und A-DIol waren vor der HCG-Zufuhr erhöht und zeigten unter HCG — von einzelnen Ausnahmen abgesehen — keinen signifikanten Anstieg. Die Messung der LH-Spiegel ergab stark erhöhte Werte während der ersten Therapiephase. In der Therapiepause, während der 2. Therapiephase und am Ende der Behandlung lagen die LH-Konzentrationen wieder in Höhe der Ausgangswerte. Das Absinken der FSH-Spiegel während der HCG-Zufuhr wird auf den hemmenden Einfluß der ansteigenden Testosteronspiegel zurückgeführt. Unter der HCG-Zufuhr zeigten Körpergewicht, Serumeiweißspiegel, Hämoglobin und Hämatokrit keinen signifikanten Anstieg im Vergleich zu den vorher erhobenen Befunden. Ebenso war eine Besserung der bei 8 Patienten nachgewiesenen schweren Fertilitätsstörungen nicht festzustellen. Die erhobenen Befunde sprechen dafür, daß bei Patienten mit chronischer Niereninsuffizienz eine schwere urämisch-toxische Schädigung des Leydigzell-Systems vorliegt, die durch die Dauerdialysebehandlung nicht beseitigt wird. Der im Vergleich zu den stark erniedrigten Testosteronspiegeln inadäquate Anstieg der Gonadotropine erklärt sich möglicherweise durch einen negativen feed-back-Effekt der Testosteronmetaboliten. Die erhöht gefundenen Werte dieser Abbauprodukte kommen wahrscheinlich durch Akkumulation bei gestörter Nierenfunktion zustande.
    Notes: Summary Thirtheen male patients with chronic renal failure undergoing regular dialysis treatment (2 × 8−10 hours/week) were treated with gonadotropins (HCG, Primogonyl ©) primarily 2 × 2,000 IU/week and later 2,000 IU/week. Before HCG administration and during 4-months HCG-therapy testosterone, dihydrotestosterone, Androstandiol, LH and FSH levels were determined by RIA-methods in 7–14 days intervals. Before HCG-application plasma testosterone levels were low and did not increase in the course of regular dialysis treatment. Derivates from testosterone like dihydrotestosterone and Androstandiol were elevated in plasma, presumably because of accumulation in renal failure. LH-levels were slightly elevated on the average. FSH-levels showed high individual variation but also seemed to be elevated on the average. HCG stimulation by exogenous HCG administration for short time resulted in a insufficient rise of testosterone levels as compared to normals. During prolonged HCG administration plasma testosterone levels increased to normal but dropped immediately after cessation of therapy or reduction to less than 2,000 IU HCG twice/week. Body weight, plasma proteins, haematocrite and fertility did not improve significantly. These results indicate that in chronic renal failure androgen synthesis by testicular tissue is seriously impaired and does not improve under usual dialysis treatment. Feedback regulation of testosterone levels by increase of LH levels seems not to be sufficient although pituitary response is found to be normal. This may be explained by elevated levels of testosterone derivates which exert negative feedback effects.
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