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Biomedical subjects

C Norris

Publications and source records attributed to C Norris.

At least 91 records · Page 5Linked to original sources
PubMed1978

Effect of a high protein (meat) intake on calcium metabolism in man.

The effect of a high protein (meat) intake of 2 g/kg on the calcium excretions and retention and on the intestinal calcium absorption was studied in man. In the control study the protein intake averaged 1 g/kg. The studies were carried out during a low calcium intake of 200 mg/day and a normal calcium intake of 800 mg/day. Two additional studies were carried out during a calcium intake of 1100 mg/day and one during a 2000 mg calcium intake. During the high protein-low calcium intake and during the 800 mg calcium intake the urinary calcium did not significantly increase. It increased moderately in two studies during the higher calcium intakes, however, these excretions decreased with time to control levels. The lack of a significant increase of the urinary calcium in the majority of the studies is probably due to the higher phosphorus content of the high protein intake. The calcium absorption, determined with 47Ca, the fecal calcium and calcium balances did not differ significantly during the high protein intake. In studies carried out during a low protein (meat) intake of 0.5 g/kg the urinary calcium changed little and the fecal calcium, the 47Ca absorption, and the calcium balance remained unchanged.

Adult↗
PubMed1978

A simple, sensitive method for the quantitation of kanamycin in tissue and biological fluids.

A method is described for the quantitative determination of kanamycin in blood, urine, cochlear perilymph and kidney. The method is simple, involving only protein precipitation, chromatographic separation and fluorometric determination following reaction with fluorescamine. The method is sensitive, determining as little as 80--100 ng/ml of kanamycin. The method is reliable, recovering better than 90% of the kanamycin added to the fluids and tissues mentioned. It is also less cumbersome and less expensive than other methods currently used.

Animals↗
PubMed1976

Effect of conventional and newer forms of treatment on calcium absorption in osteoporosis.

Studies carried out in this Research Unit and by others have shown that patients with osteoporosis absorb less calcium from a high calcium intake than do patients without osteoporosis. To determine whether various treatment modalities would increase the intestinal absorption of calcium, the effects of conventional and new methods were investigated. Tracer doses of 47Ca were given orally to determine the absorption of calcium. Calcium balances were also determined. Estrogen decreased urinary calcium and testosterone increased the nitrogen balance. Vitamin D and strontium increased the urinary calcium but did not increase calcium absorption. Of the newer compounds, fluoride did not affect calcium absorption but decreased urinary calcium. Phosphate had a similar effect. Infusions containing up to 15 mg calcium/kg, given for 6 or 10 days, increased the retention of calcium but did not increase its absorption.

Adult↗
PubMed1975

Effect of calcium and phosphorus on fluoride metabolism in man.

The effect of orally administered calcium and phosphorus on the fluoride balance was studied in man during a low fluoride intake of about 4 mg/day and a high fluoride intake of 14 mg/day. Three calcium intake levels averaging 223, 1,481, and 2,312 mg and two phosphorus intakes averaging 915 and 1,430 mg/day were used. Calcium or phosphorus used singly or combined did not affect the urinary fluoride. Increasing the calcium intake from an average of 223 to 1,481 and to 2,312 mg/day during the low fluoride intake increased the fecal fluoride only slightly, from 0.13 to 0.17 and 0.20 mg/day, respectively, and during high fluoride intake from 0.31 to 0.58 and 0.56 mg/day, respectively. The addition of phosphorus to the low calcium intake did not change the fecal fluoride excretion during either low or high fluoride intake, but the fecal fluoride increased during the two higher calcium intakes by a factor of 1.5. As the fecal fluoride was very low in the control study and was still relatively low in the experimental studies, the increase in fecal fluoride did not change the fluoride balances. The studies have shown that the increased levels of calcium and phosphorus used had little effect on fluoride metabloism in man.

Adult↗
PubMed1975

Regulation and grinding ability of grit in the gizzard of Norwegian willow ptarmigan (Lagopus lagopus).

Fluctuations in grit composition in the gizzards of willow ptarmigans and the grinding ability of various grit assortments from wild ptarmigans were examined. We confirmed reports of other investigators that larger, fewer and rounder stones were present in the winter than in the autumn. Experiments showed that ptarmigans prefer stones with diameters between 2-5 mm. Birds on a constant diet maintained a constant stone intake throughout the year. The composition of gizzard grit was influenced by the availability of stones as well as of the type of food the ptarmigans ate. Using an artificial gizzard, grit from birds shot during the autumn was found to be a more efficient grinding material than grit from winter birds. We suggest that other functions than grinding, such as supplying minerals, may be equally important functions of the grit.

Animals↗