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  • 1
    ISSN: 1432-0568
    Keywords: Pantothenic acid deficiency ; Corticotropin-releasing factor ; Corticoids ; Histologie ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the outer layer of the rat median eminence “Gomori-positive” granules occur which are assumed to be the morphological correlate of the corticotropin-releasing factor (CRF). The present study was carried out in order to establish whether the amount of these CRF-granules is influenced by a pantothenic acid (PA)-deficiency, which is known to result in an inhibition of corticosteroid production. Female SPF Wistar rats were used. PA-deficiency was induced by PA-free nutrition and/or administration of the PA-antagonist Ω-methyl-PA. Corresponding experimental groups were given either tap water or a solution of 1% NaCl and 5% glucose in tap water to drink. In rats fed with a diet free of PA and in addition treated with Ω-methyl-PA a severe disturbance of the corticoid balance developed within 6 weeks. The corticosterone production was depressed to about 11–16% of the control values. The adrenal cortex showed necrotic changes which either involved the whole parenchyma or were confined to the inner zones. In those animals in which a subcapsular region, in its extent corresponding to the zona glomerulosa, remained intact, an augmentation of the CRF-granules was observed. In those animals, however, in which the whole adrenal cortex was damaged, the amount of CRF-granules did not increase. Administration of the 1% NaCl containing drinking fluid did not influence the augmentation of the CRF granules, but had a protective effect on the development of necrotic changes in the zona glomerulosa of the adrenal cortex. The findings show that a functional relationship exists between the inner zones of the adrenal cortex and the CRF-granules in the median eminence.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 157 (1998), S. S135 
    ISSN: 1432-1076
    Keywords: Key words Homocysteine ; Folate ; Vitamin B12 ; Vitamin B6 ; Healthy population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The metabolism of a substrate is closely linked to that of its cofactor(s). In the case of homocysteine, the vitamins B12, B6 and folic acid are involved in its metabolism, acting as coenzymes. To evaluate the role of these vitamins as determinants of homocysteine concentration in the healthy population, only data from this group should be considered. Studies dealing with vitamin deficiency and the occurrence of elevated homocysteine levels as well as with the treatment of elevated homocysteine levels by supplementing one or more of the vitamins have to be omitted. In the healthy population with “normal” homocysteine levels and a vitamin status currently regarded as adequate, folate seems to play the most important role in determining the blood homocysteine level. This has been derived from supplementation studies as well as from statistical correlation analysis regarding the relationship of the three vitamins to homocysteine. Until now, recommended dietary allowances for folate have been defined on the basis of the absence of clinical signs of deficiency as well as morphological alterations of blood cells indicating an early stage of folate deficiency. However, these recommended dietary allowance values do not seem to be sufficient when looking at homocysteine as a functional parameter of folate status. Due to the important role of folate status as a determinant of homocysteine concentration, it may be necessary to redefine an adequate blood folate level and probably reformulate dietary allowances for this B-vitamin.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 669 (1992), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0039-128X
    Keywords: adrenarche ; body surface area ; creatinine ; dehydroepiandrosterone sulfate (DHEAS) ; radioimmunoassay ; urinary excretion
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 254 (1993), S. 1293-1294 
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 254 (1993), S. 1388-1389 
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 28 (1989), S. 130-141 
    ISSN: 1436-6215
    Keywords: bioavailability ; folic acid ; pharmaceutical preparation ; Bioverfügbarkeit ; Folsäure ; Arzneimittelzubereitung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Untersuchungen zur Bioverfügbarkeit essentieller Mikronährstoffe (Vitamine, Mineralstoffe, Spurenelemente) aus Lebensmitteln wie auch aus Arzneimittelzubereitungen sind von entscheidender Bedeutung bei der Beurteilung des jeweiligen Beitrages zur Nährstoffversorgung bzw. zur Abschätzung eines möglichen Therapieerfolges. Die Durchführung derartiger Prüfungen erfolgt in der Praxis nicht selten nach unterschiedlichen Kriterien. Deshalb werden zunächst die Grundsätze erläutert, die bei entsprechenden Prüfungen für eine valide Bewertung von Nähr- bzw. Wirkstoffgemischen oder Monopräparaten bedeutsam sind. Abschließend wird die Ermittlung der Bioverfügbarkeit von Folsäure an einem Beispiel demonstriert. Zur Testung werden die postresorptiven Kurvenintegrale ermittelt, wobei die Daten auf das basale Ausgangsniveau bezogen werden. Zur Beurteilung der Bioverfügbarkeit findet neben dem maximalen Vitaminanstieg im Serum sowie der Zeit bis zum Konzentrationsmaximum insbesondere der Bioverfügbarkeitsquotient von Test- und Referenzzubereitung mit seinem 95%-VB Berücksichtigung. Die Ergebnisse zeigen, daß die exemplarisch eingesetzte Testsubstanz, 5-Formyl-Tetrahydrofolsäure, eine sehr gute Bioverfügbarkeit aufweist und daß unter Anwendung der beschriebenen Rahmenbedingungen eine objektive Bewertung der Bioverfügbarkeit möglich ist.
    Notes: Summary Bioavailability studies of micronutrients (vitamins, minerals) from different food stuffs, as well as from pharmaceutical preparations are of great importance for the calculation of nutrient intake and/or the evaluation of the therapeutic value. In practice, bioavailability studies are not generally performed on a standardized level. For this reason basic criterions are presented and discussed. Finally, the investigation of the bioavailability of folate is demonstrated by an example. The parameters investigated are: the maximal concentration (cmax), the time to reach this maximum (tmax), and especially the bioavailability ratio determined from the area under the curve (AUC) after administration of the folic acid containing test and reference preparation. The results indicate that 5-formyl-tetrahydrofolic acid given in the tested form has nearly the same bioavailability (ratio: 1.02) as folic acid (pteroylmonoglutamic acid) in aqueous solution.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 35 (1996), S. 32-38 
    ISSN: 1436-6215
    Keywords: Dietary fiber ; dehydroepiandrosterone sulfate ; dehydroepiandrosterone ; 3α-androstanediol glucuronide ; peptide ; steroid metabolism ; Diätetischer Ballaststoff ; Dehydroepiandrosteronsulfat ; Dehydroepiandrosteron ; 3α-Androstendiol glucuronide ; steroidmetabolismus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Es gibt kaum Untersuchungen zu den Auswirkungen einzelner Nahrungskomponenten auf die Plasmaspiegel von Dehydroepiandrosteron (DHEA) und Dehydroepiandrosteron-Sulfat (DHEAS). Insbesondere fehlen Studien zum Einfluß von speziellen Ballaststoffen. Der Effekt von Pektin (ein typischer Ballaststoff mit Wirkung auf die enterohepatische Rezirkulation von Gallensäuren) wurde in 3 aufeinanderfolgenden, jeweils 4tägigen Diätphasen an 6 männlichen Erwachsenen im Rahmen einer randomisierten cross-over-Studie überprüft. Am Ende jeder Diätphase (konstante Nahrungszusammensetzung, Pektinzusatz: 0, 15 bzw. 30 g/die) wurden 24h-Urine gesammelt und venöses Blut entnommen. Die Pektinzulagen führten weder bei DHEA und Cortisol noch beim wichtigsten Plasmabindungsprotein von DHEAS, dem Albumin, zu Veränderungen der Plasmakonzentrationen. Auch blieb die Ausscheidung verschiedener Urin-Analyte (einschließlich des DHEAS) konstant. Allerdings zeigten sich bei 30 bzw. 15 versus 0 g Pektin/die Effekte in bezug auf Plasma-DHEAS (9,3±2,8; 9,2±2,6; 8,0±3,1 µmol/L, p〈0,01) und Plasma-Cholesterin (4,4±0,7; 4,5±0,7; 4,7±0,8 mmol/L, p=0,1). Die Auswirkungen einer veränderten Pektinzufuhr auf zirkulierendes DHEAS und Cholesterin sind also offensichtlich entgegengerichtet. Die Ursache hierfür ist nicht bekannt, allerdings wird eine diätetisch induzierte Änderung der Bindungseigenschaften von Albumin für DHEAS vermutet. Die Befunde deuten an, daß der biologisch aktive, nicht proteingebundene Anteil des zirkulierenden DHEAS (der durch die renale DHEAS-Ausscheidung reflektiert wird) nicht notwendigerweise verändert sein muß, wenn das Gesamt-DHEAS im Plasma variiert.
    Notes: Summary Studies specifically investigating the effects of single dietary components on plasma levels of dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) are rare. Especially no data is available with regard to specific dietary fibers. Therefore, the impact of pectin (a representative fiber that affects the enterohepatic recirculation of bile acids) was studied in a randomized crossover trial consisting of three diet periods characterized by the same food supply and daily doses of 0 g, 15 g or 30 g pectin. Blood and 24-h-urine samples were collected at the end of each 4-day diet period from 6 healthy male volunteers. Plasma levels of DHEA, cortisol and the major binding protein of DHEAS albumin remained unchanged with the varying pectin supplements. Also, no changes were observed for several urinary analytes including urinary DHEAS. However, effects of pectin intake (30, 15 versus 0 g/d) were seen for plasma DHEAS (9.3±2.8, 9.2±2.6, 8.0±3.1 µmol/L, p〈0.01) and total plasma cholesterol (4.4±0.7, 4.5±0.7, 4.7±0.8 mmol/L, p=0.1). Obviously, the altered intake of fiber in the form of pectin affects plasma concentrations of DHEAS and cholesterol in an opposite direction. The reason for this is not known but a dietetically induced modulation of the binding properties of plasma albumin for DHEAS appears possible. Our findings suggest that the target tissue-available, not protein-bound fraction of circulating DHEAS (as reflected by the renal DHEAS output) is not necessarily altered when total plasma concentrations of DHEAS vary.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Optimierung der quantitativen Erfassung von Diäthylstilböstrol und Dienöstrol mit der schnellen Flüssigkeits-Chromatographie wird beschrieben. Von der Erfassungsgrenze von 2 ng/20 mm3 Einspritzmenge bis in den oberen gemessenen Bereich von 500 ng/20 mm3 Einspritzmenge wurde eine lineare Eichkurve erhalten.
    Notes: Summary Optimisation of the estimation of diethylstilboestrol and dienoestrol by high-speed liquid chromatography is presented. Calibration has been shown to be linear between the detection limit (2 ng/20 mm3 per injection) to the highest measured concentration of 500 ng/20 mm3 per injection).
    Type of Medium: Electronic Resource
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