Effects of zinc on the mineralization of bone nodules from human osteoblast-like cells.

Zinc is an important mineral that is required for normal bone development. However, the direct effects of zinc on the mineralization of bone cells of human origin are not clear. The objective of this study was to determine the effects of zinc on the differentiation of SaOS-2 human osteoblastlike cells and the formation of mineralized bone nodules. Cells were cultured for 8 d and then transferred to zinc-free medium and treated with varying concentrations (0-50 microM) of zinc. Alkaline phosphatase (ALP) activity was used as a measure of osteoblast differentiation, and bone nodules were detected by von Kossa staining. After 4, 6, and 8 d of treatment, zinc increased ALP activity at 1 and 10 microM, but decreased activity at 50 microM. After 9 d of treatment, zinc increased both the number and area of mineralized bone nodules at low concentrations (1 and 10 microM), but decreased both at higher concentrations (25 and 50 microM). These findings demonstrate that zinc has biphasic effects on the differentiation and mineralization of human osteoblast-like cells.

Effect of dietary zinc on the levels and distribution of Fatty acids and vitamin A in blood plasma chylomicrons.

The aim of this work was to explore the effects of a low- and high-zinc diet and vitamin Aon the distribution of fatty acids in chylomicrons. Mongolian Gerbils were fed a basal diet (for 3 wk) containing 8 or 38 mg zinc/kg of feed (low-zinc group [termed LZ group] and saturated zinc group [termed SZ group], respectively). The following day, the animals were given sunflower oil containing 50 nmol vitamin A. The results showed that the concentration of zinc in blood plasma was similar in both groups. The amount of plasma chylomicrons was lower in the LZ group than in the SZ group (p < 0.001). The concentration of retinol in blood plasma was lower in the LZ group than in the SZ group (p < 0.01). However, the results demonstrated an increase in the blood plasma retinol concentration in the LZ group compared to the SZ group when calculated per milligram of plasma chylomicrons (p < 0.01). In plasma chylomicrons, fatty acids corresponding to 16:0, 16:1, 17:0, 17:1, 18:0, 18:1, 18:2, 18:3, 20:0, 21:0, and 20:4 were detected. The fatty acid distribution was similar in both groups. There was no major difference in the concentration of fatty acids in plasma chylomicrons between both experimental groups, except for 20:4 (a lower amount was found in the SZ group). Our results show that dietary zinc influences both the amount of chylomicrons in blood plasma and the concentrations of retinol and arachidonic acid in chylomicrons.

The dry plant extract of common bean seed (Phaseoli vulgari pericarpium) does not have an affect on postprandial glycemia in healthy human subject.

The aim of present study was to assess the effects and safety of a dry Phaseoli vulgari pericarpium (PVP) extract on postprandial glycemia in healthy participants. A randomized crossover experiment where participants received either PVP extract or placebo. Chemical compounds in dry extract were assessed by established methods. Eighteen healthy participants (9 male and 9 female) aged 29+/-4,8 years, body mass index (BMI) 23+/-3,7 kg/m(2) were recruited among students and staff at the Faculty of Pharmacy, University of Belgrade. All participants were able to follow the study protocol without difficulty. The participants received either PVP extract or placebo 30 minutes before a 50g oral glucose tolerance test (OGTT). The protocol followed the guidelines for the OGTT with blood samples drawn at 0, 15, 30, 60, 90 and 120 min. This study demonstrated that there was no significantly effect of the PVP extract on incremental blood glucose (IBG) and their areas under the curve (AUC) neither male nor female participants. However, IBG together with AUC changes were significantly lower in male compared with female participants in treated and untreated groups. The presence of chrome, soluble fiber, vitamin C, protein, glucose and lectins were also quantified. The applied amount of PVP extract was unable to produce the postprandial hypoglycemia. We assumed that amounts of chrome, soluble fiber, vitamin C which have beneficial effects on diabetes treatment were sufficient to produce hypoglycemia.