scholarly journals Plasma Level of 1, 25-Dihydroxyvitamin D in Neonatal Calves

1983 ◽  
Vol 45 (4) ◽  
pp. 533-535 ◽  
Author(s):  
Yoshihisa NAITO ◽  
Eiji WATANABE ◽  
Akinori OSHIBE ◽  
Reeko SATO ◽  
Daizo MURAKAMI
2007 ◽  
Vol 97 (4) ◽  
pp. 611-616 ◽  
Author(s):  
Jean-Philippe Bonjour ◽  
Thierry Chevalley ◽  
Patrice Fardellone

An association between Ca intake and the risk of prostate cancer has been reported in some but not all epidemiological studies. Assuming that a pathophysiological relationship would underlie this association, a favoured hypothesis proposes that relatively high Ca consumption could promote prostate cancer by reducing the production of 1,25-dihydroxyvitamin D (1,25(OH)2D; calcitriol), the hormonal form of vitamin D. The present review analyses the plausibility of this hypothesis by considering the quantitative relationships linking Ca intake to 1,25(OH)2D production and action in healthy conditions and in prostate cancer. Changes in the plasma level of 1,25(OH)2D in response to Ca intake are of very small magnitude as compared with the variations required to influence the proliferation and differentiation of prostate cancer cells. In most studies, 1,25(OH)2D plasma level was not found to be reduced in patients with prostate cancer. The possibility that the level of 1,25(OH)2D in prostate cells is decreased with a high-Ca diet has not been documented. Furthermore, a recent randomised placebo-controlled trial did not indicate that Ca supplementation increases the relative risk of prostate cancer in men. In conclusion, the existence of a pathophysiological link between relatively high Ca intake and consequent low production and circulation level of 1,25(OH)2D that might promote the development of prostate cancer in men remains so far an hypothesis, the plausibility of which is not supported by the analysis of available clinical data.


2000 ◽  
Vol 70 (3) ◽  
pp. 92-101 ◽  
Author(s):  
Burim Ametaj ◽  
Brian Nonnecke ◽  
Ronald Horst ◽  
Donald Beitz

Individual and combined effects of several isomers of retinoic acid (RA) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on interferon-gamma (IFN-gamma) secretion by blood mononuclear leukocytes (MNL) from nulliparous and postparturient Holstein cattle were evaluated in vitro. In the first experiment, effects on incubation period (24 to 72 hours) and time of supplementation (0 to 32 hours) with all-trans, 9-cis, 13-cis-, and 9,13-dicis-RAs (0 to 100 nM) on IFN-gamma secretion by pokeweed mitogen (PWM)-stimulated (0 and 10 mug/ml) MNL from nulliparous cattle were evaluated. In the second experiment, MNL from postparturient cows (bled at 0, 2, 4, and 16 days postpartum) were stimulated with PWM (0 and 10 mug/ml) in the presence of RA isomers (9-cis- or 9,13-dicis-RA; 0 to 100 nM), 1,25-(OH)2D3 (0 to 100 nM), or with combinations of these metabolites. The results show that individual isomers of RA had no effect on IFN-gamma secretion by PWM-stimulated MNL from nulliparous or postparturient cows. Furthermore 1,25-dihydroxyvitamin D3 inhibited IFN-gamma secretion by MNL from nulliparous and postparturient dairy cows; however, the degree of inhibition was greater when 9-cis- and 9,13-dicis-RA were also present in the cultures. Finally mononuclear leukocytes from postparturient dairy cows produced substantially less IFN-gamma than did MNL from nulliparous cattle. It is concluded that retinoic acids individually did not affect the capacity of leukocytes from dairy cattle to secrete IFN-gamma. This result is in marked contrast to studies in monogastric species indicating that RAs inhibit IFN-gamma secretion by peripheral blood T cells. Inhibition of IFN-gamma secretion by 1,25-(OH)2D3 was potentiated by 9-cis- and 9,13-di-cis-retinoics acids, suggesting that an excess of dietary vitamins A and D may compromise further the naturally immunosuppressed postparturient dairy cow. Additional research is necessary to determine if the combined effects of these metabolites on IFN-gamma secretion represent an increased susceptibility of the dairy cow to infectious diseases during the periparturient period. Lower secretion of IFN-gamma by MNL from postpartutient dairy cows, relative to nulliparous cattle, suggests that recently-calved cows are naturally immunosuppressed.


1979 ◽  
Vol 41 (02) ◽  
pp. 365-383 ◽  
Author(s):  
C Kluft

SummaryEffects due to plasma plasminogen activators and proactivators are usually studied in assay systems where inhibitors influence the activity and where the degree of activation of proactivators is unknown. Quantitative information on activator and proactivator levels in plasma is therefore not availableStudies on the precipitating and activating properties of dextran sulphate in euglobulin fractionation presented in this paper resulted in the preparation of a fraction in which there was optimal recovery and optimal activation of a number of plasminogen activators and proactivators from human plasma. The quantitative assay of these activators on plasminogen-rich fibrin plates required the addition of flufenamate to eliminate inhibitors. The response on the fibrin plates (lysed zones) could be coverted to arbitrary blood activator units (BAU). Consequently, a new activator assay which enables one to quantitatively determine the plasma level of plasminogen activators and proactivators together is introduced.Two different contributions could be distinguished: an activity originating from extrinsic activator and one originating from intrinsic proactivators. The former could be assayed separately by means of its resistance to inhibition by Cl-inactivator. Considering the relative concentrations of extrinsic and intrinsic activators, an impression of the pattern of activator content in plasma was gained. In morning plasma with baseline levels of fibrinolysis, the amount of extrinsic activator was negligible as compared to the level of potentially active intrinsic activators. Consequently, the new assay nearly exclusively determines the level of intrinsic activators in morning plasma. A pilot study gave a fairly stable level of 100 ± 15 BAU/ml (n = 50). When fibrinolysis was stimulated by venous occlusion (15 min), the amount of extrinsic activator was greatly increased, reaching a total activator level of 249 ± 27 BAU/ml (n = 7).


1991 ◽  
Vol 65 (04) ◽  
pp. 364-368 ◽  
Author(s):  
Hideo Wada ◽  
Shigehisa Tamaki ◽  
Motoaki Tanigawa ◽  
Mikio Takagi ◽  
Yoshitaka Mori ◽  
...  

SummaryThe plasma level of interleukin-1β (IL-1β) was determined in normal individuals, patients with disseminated intravascular coagulation (DIC), patients in the pre-DIC period (within 7 days before the onset of DIC), and non-DIC patients to examine the relationship between DIC and the plasma ILlp level. The plasma IL-1β level was 0-0.085 ng/ml in normal individuals, with little difference being seen according to related age. It was significantly higher in the DIC group (0.19 ± 0.19 ng/ml) than in the pre-DIC group (0.05 ± 0.08 ng/ml) or the non-DIC group (0.09 ± 0.01 ng/ml). The plasma IL-1β level was not markedly elevated in leukemia patients, even in the DIC group, but it was significantly increased in the DIC group of solid cancer patients and was generally elevated in patients with sepsis. It was markedly elevated to 0.39 ± 0.26 ng/ml in patients with organ failure. When mononuclear cells were incubated with lipopolysaccharide, it was found that IL-1β, tumor necrosis factor, and tissue factor (TF) were released into the medium, and there was an increase of TF release from endothelial cells incubated with this medium. These results suggest that the increase in IL-Iβ reflected the activation of monocytes and may be an important factor in DIC and its associated organ failure.


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