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  • 1
    ISSN: 0032-8332
    Keywords: Zinc deficiency ; Rhesus monkey ; Purified diets ; Pregnancy ; Reproduction ; Zinc ; Nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although non-human primates are widely used models of human diseases, often studied for long periods of time, their dietary requirements are not well defined. Over a two—three-year time period, female rhesus macaques were fed either a marginally zinc-deprived diet or a comparable zinc replete purified diet. The purified diets were based on current NRC recommendations. Interestingly poor pregnancy outcome was noted in both the zinc-deprived as well as in the control group. Twenty-eight percent of controls (N=16) and 20% of zinc-deprived animals (N=15) failed to conceive after at least seven matings. Pregnancy loss was also high in both groups of animals including 31% of conceptions in controls (N=11) and 33% of conceptions in zinc deficient animals (N=12). The majority of pregnancy losses occurred after animals had been fed purified diet for over two years. In contrast, normal colony pregnancy loss is estimated at 11%. Furthermore, 3 of 18 live-born infants died prior to 7 months of age and one third of surviving offspring were growth-retarded during the 1st year of life compared to established colony norms. Our data demonstrate the difficulty of constructing adequate purified diets for long-term studies in primates even when based upon available and recommended nutritional information.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0730-2312
    Keywords: α2-macroglobulin ; albumin ; placenta ; zinc ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We have investigated the binding and internalization of α2-macroglobulin and serum albumin by human placental syncytiotrophoblast cells in vitro. The time course (obtained at 4°C) of α2-macroglobulin binding indicated that an equilibrium was reached after 4 h. The binding of 125I-labelled α2-macroglobulin to syncytiotrophoblast cells was competitively reduced in the presence of excess unlabelled α2-macroglobulin. When the concentration-dependence of binding was examined over a wide concentration range, non-linear regression analysis yielded a Kd of 6.4 nM. In the case of albumin, binding was weak and ligand dissociated from the cell surface during aqueous washing making it impractical to analyze the binding reaction. In other experiments, syncytiotrophoblast cells were incubated with 125I-labelled α2-macroglobulin at 37°C. Under these conditions, trypsin-resistant cell-associated radioactivity increased with time consistent with ligand internalization. 125I-Labelled-ligand was internalized with a t1/2 of about 5 min. After a lag period some radioactivity was released back into the incubation medium. When measured at times up to 210 min, this was found to consist of mostly TCA-precipitable material that had been lost from the cell surface. However, when the incubation was extended to 24 h, almost 15% of the initial cell-associated radioactivity was released to the extracellular medium as TCA-soluble material, consistent with a slow rate of ligand degradation. The specific binding of 65Zn-labelled α2M was similar to that of the 125I-labelled ligand and trypsin-resistance measurements provided evidence of α2M-mediated 65Zn uptake. These results support a role for syncytiotrophoblast in the metabolism of α2-macroglobulin during pregnancy and are also consistent with a role for α2-macroglobulin in the maternal-fetal transport of zinc. J. Cell. Biochem. 68:427-435, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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