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K J Ellis

Publications and source records attributed to K J Ellis.

At least 145 records · Page 8Linked to original sources
PubMed1976

Effect of graded doses of cortisol on total body calcium in rats.

Male rats with an average body weight of 250 g were injected (sc) daily for 4 wk with 0.05, 0.20, 0.75, or 3.00 mg of cortisol acetate. Intact and adrenalectomized control animals were injected daily with 0.1 ml of vehicle (corn oil). Total body calcium (TBCa) was measured weekly in each rat by in vivo neutron activation analysis. The gain is body weight of rats treated with 0.75 mg cortisol was significantly less than controls, and the animals treated with 3.00 mg cortisol lost weight. In spite of these differences in body weight, the TBCa of all rats increased to an equal degree from an average of 1.93 g to 2.81 g in 4 wk. In addition, there were no significant differences in tibial ash calcium. However, calcium (mg) per unit length (mm) of tibia was increased in rats treated with the higher doses of cortisol; thus bone density was increased. These results demonstrate that the TBCa increases even when rats are subjected to cortisol. This is explained in part by the normal rate of intestinal calcium absorption in cortisol-treated rats.

Animals↗
PubMed1976

Effect of hydrocortisone on total body calcium in rats.

Administration of 5 mg. of hydrocortisone acetate to rats every other day for 2 weeks resulted in growth retardation and weight loss as indicated by body weights of experimental animals, which averaged 33 per cent lower than those of the controls, and a significant decrease in the length of the tibiae and femurs (p less than 0.01 for treated vs controls). However, despite the smaller size of the treated animals, the values for total body calcium (TBCa) and the calcium in the tibia and femur did not differ significantly from control values. Thus, there was more calcium per unit length of bone, resulting in an increase in the skeletal density of treated rats. This finding was confirmed by x-ray examination of these bones. The net intestinal absorption of calcium (rate of initial entry) calculated from plasma levels following an oral and intravenous dose of 47Ca and 85Sr, respectively, was not significantly different in hydrocortisone-treated rats compared to controls. This would indicate that the rate of intestinal absorption of calcium is unimpaired despite the administration of massive doses and corticosteroids. When the animals were placed on a calcium-deficient diet, both TBCa and tibia and femur calcium levels were decreased. Subsequent administration and hydrocortisone did not alter the calcium values. The results of this study are compatible with the hypothesis that hydrocortisone promotes weight loss, retards growth, but inhibits the rate of bone resorption.

Animals↗
PubMed1975

Creatinine excretion and total body potassium in renal failure.

Total body potassium (TB K) and daily urinary creatinine excretion were measured in 12 patients with mild chronic renal disease (CCr/1.73 m2 BSA greater than 40 ml/min, Group I) and 12 patients with severe renal disease (CCr/1.73 m2 BSA less than 19 ml/min, Group II). Creatinine excretion as a function of total body potassium was significantly lower in the males and females of Group II as compared to males and females in Group I. TB K was linearly related to creatinine excretion in both groups of patients. Mean TB K was not significantly different from mean predicted normal values (TB Kp) in both groups. The decreased creatinine excretion observed in severe renal failure cannot be due to a significant loss of lean body mass because TB K was not significantly decreased below predicted normal values. Decreased creatinine biosynthesis, alternate routes of excretion, metabolic reutilization, or conversion of creatinine to other metabolites may have contributed to the decreased creatinine excretion noted in this group of patients with renal failure.

Body Weight↗
PubMed1975

Correlation of radial bone mineral content with total body calcium in chronic renal failure.

Loss of bone mineral of the skeleton in renal disease can be measured directly by total body neutron activation analysis (TBNAA), and also by an absorptiometric technique applied to the appendicular skeleton (radius). In the present study the results of these two techniques are compared in 25 patients with renal insufficiency, 53 patients with end-stage renal failure on dialysis, and 24 normal control subjects. It is apparent that there is good correlation between total body calcium(TBCa) and bone mineral content (BMC) in all groups studied. The correlation in the normal contrast group was 0.944 as compared to 0.919 for the renal patients and 0.892 for patients with end-stage renal failure on dialysis. In order to measure the relative deficit in TBCa in individual patients from the absolute Ca measurement, it is necessary to normalize the data for sex, age, and skeletal size. For this purpose, an empirically derived relationship was used to predict the normal skeletal Ca in each subject, based on weight, height, sex, and age. The measured TBCa divided by the predicted TBCa is referred to as the calcium ratio. This ratio is useful in expressing the relative deficit of Ca in individual renal patients. In similar manner, BMC data were normalized, with the same relationship used to obtain BMC ratios. The normalization procedures allow both the TBCa and BMC measurements to be used to quantitate the Ca deficit in individual patients with renal insufficiency. However, the correlation coefficient relating changes in TBCa and BMC in individual patients on dialysis was very poor (0.25). It is clear that the BMC measurement alone cannot always predict the level of the total body Ca in individual patients with renal failure. In like manner, TBCa measurement alone does not define the distribution of total body Ca between the skeleton and soft tissue in these patients. However, taken together, the BMC measure along with that of TBCa does suggest possible alterations in the skeletal calcium distribution associated with renal disease.

Absorption↗