Don W. Watkins

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Following lesions of the dorsal column nuclei, spinal cord and sensorimotor cortex, anterograde degeneration was traced to a common target in the central midbrain; the intercollicular terminal zone. Although not all the midbrain projections of the three pathways are contained within this zone, it receives overlapping projections from each of the three(More)
In order to evaluate whether the hypozincemia associated with chronic renal failure represents true negative zinc balance, male Lewis rats were randomized and pair-fed zinc replete (+Zn) or deplete (-Zn) diets. Subsequently, each animal underwent one- and two-thirds nephrectomy, or a sham operation. Complete balances for zinc, calcium, and magnesium were(More)
To investigate the role of zinc depletion in the response of calcitriol to a single provocative stimulus, we studied vitamin D metabolites, parathyroid hormone (PTH), and mineral balance during phosphorus depletion in animals with different zinc nutritional status. Male Lewis rats (66) were pair fed normal phosphorus (NP), zinc-replete (+) or -deplete (-)(More)
Cholestyramine is an effective drug for the reduction of plasma cholesterol because of its ability to sequester intestinal bile acids. Since metabolic alterations, including diminished intestinal absorption of vitamin D and osteomalacia have been reported with long-term use of this resin, the influence of cholestyramine on dietary balance of four mineral(More)
BACKGROUND Previous studies from our laboratories suggested that zinc depletion reduces the circulating level of 1,25-dihydroxycholecalciferol (1,25(OH)2D, calcitriol) in calcium- and phosphorus-depleted rats with normal renal function, and rats with uremia. Since calcitriol synthesis is in part dependent on renal function, we studied levels of circulating(More)
Male Lewis rats (n = 27) were fed a nonpurified diet containing 0.9% calcium, 0.7% phosphorus, and 0.005% zinc until 8 wk of age. At this time rats were assigned randomly to one of two groups. Both groups were fed a low calcium, low zinc, purified diet (0.2% calcium, 0.4% phosphorus, less than 0.00007% zinc), but one group was fed 1.78 mg Zn/(animal.d). The(More)
The effect of zinc on sodium coupled glucose uptake was studied in pig intestinal brush border membrane vesicles. In this system zinc inhibited glucose uptake and appeared to have a K i of 0.25 mM. When tested by spectrophotometry, electron microscopy and protein determination following centrifugation, no evidence of significant vesicle aggregation was(More)