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J M Letteri

Publications and source records attributed to J M Letteri.

34 records · Page 2Linked to original sources
PubMed1977

Distribution of calcium in the rat due to chronic renal failure.

During the 12 weeks following 5/6 nephrectomy in rats with moderate uremia (creatinine 0.7-1.2 mg/100 ml, BUN 53-89 mg/100 ml), no significant increases in total soft tissue calcification were observed. The calcium concentration of skeletal muscle remained unchanged at 4, 8, and 12 weeks after surgery. A slight but not significant increase in skin calcium was found. However, a significant decrease in cardiac calcium was found for the uremic animals. Total body calcium as determined by neutron activation analysis was significantly lower in the uremic rat when compared with the age-matched animal. However, when normalized for body weight, the total calcium content in uremic rats did not differ from the controls. Similar findings were observed for the absolute calcium content of the tibia and when normalized for weight. Furthermore, a highly significant linear relationship (r = 0.92, p less than 0.001) was established between absolute levels of total body calcium and tibia calcium which was identical for control and uremic groups.

Animals↗
PubMed1977

Effect of hemodialysis on methylprednisolone plasma levels.

The effect of hemodialysis on methylprednisolone levels in uremia was investigated. Methylprednisolone 15 mg/kg was given intravenously over a period of 20 min to five patients undergoing routine maintenance hemodialysis. Dialysis began 5 min after the infusion ended and continued for 5 h. Pre- and post-coil plasma levels and the dialysate level of methylprednisolone were measured at intervals. Dialysance averaged 18.4 +/- 6.1 ml/min, and mean half-life 149 +/- 26 min. The volume of distribution was 0.80 of body weight. The significant dialysance of methylprednisolone may require adjustment of dosage in certain clinical situations when hemodialysis is necessary for patients receiving the steroid.

Half-Life↗
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↗