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Biomedical subjects

M Kaye

Publications and source records attributed to M Kaye.

At least 19 recordsLinked to original sources

Correction of hypophosphatemia in patients on hemodialysis using a calcium-free dialysate with added phosphate.

Three patients on long term hemodialysis were found to be hypophosphatemic. They were treated using a calcium-free dialysate to which phosphate was added to give a final concentration of 1 or 2 mmol/l. All corrected their low phosphates. Hypocalcemia developed in two patients when the calcium infusion rate was 15 ml/hour of 10% CaCl2. It is recommended that this should be increased to 20 ml/hour. Under these circumstances, correction of hypophosphatemia is possible with the transfer of approximately 30-35 mmol phosphate over a four-hour dialysis.

Adult

Staining of bone for aluminum: use of acid solochrome azurine.

Fourteen individuals on long term hemodialysis, with varying amounts of aluminum in bone from 11 to 296 mg/kg by flameless atomic absorption spectrophotometry, were examined to see whether the aluminon or acid solochrome azurine (ASA) staining reactions best approximated the chemical determination. Correlation coefficients were 0.78 for aluminon and 0.88 for ASA. Together with 11 additional patients morphometric parameters were compared with the two aluminum stains. The aluminon stain gave satisfactory results in the osteomalacic group but underestimated the amount of aluminum present in those with hyperparathyroid, mixed or aplastic disease. Some individuals showed a striking difference between the two techniques which could have led to an erroneous conclusion regarding the amount of aluminum present. The aluminon stain was pH dependent and together with ASA could be enhanced by prior heat treatment of the sections. It is recommended that ASA either replace aluminon for routine use or be used together with the aluminon stain, particularly for bones without osteomalacia or with mild to moderate aluminum storage.

Aluminum

Metastatic carcinoma of the prostate with hypercalcemia.

A patient presented with advanced cancer of the prostate and underwent bilateral orchiectomy. After 2 years, hypercalcemia developed and was managed successfully with saline diuresis, furosemide, and oral glucocorticoid therapy. It is believed that the patient's hypercalcemia was caused by a metabolic complication of progressive, advanced disease.

Adenocarcinoma

Changes in intact parathyroid hormone levels during hemodialysis following exposure to either differing dialyzate calcium concentrations or calcium-free dialysis with varying calcium infusion rates.

To determine the optimal infusion rate for calcium, when using a dialyzate which was calcium free, six patients were treated sequentially, in random order, with six different dialyzates. Three were calcium free and they were infused with replacement calcium at either 10, 15 or 20 ml/hour using 10% CaCl2. The other three used standard bicarbonate dialyzate with either 1.25, 1.5 or 1.75 mmol/l calcium. Ionized calcium and intact parathyroid hormone (Nichols IRMA PTH) were measured at the start and end of each dialysis. Ionized calcium rose slightly with 15 ml/hour calcium infusion and PTH fell 137 +/- 111 pg/ml. These changes were similar to those of 1.5 mmol/l calcium in standard bicarbonate. More PTH suppression and higher end dialysis calcium resulted from 20 ml/hour infusion or 1.75 mmol/l dialyzate calcium. It was concluded that 15 ml/hour is a suitable calcium infusion rate under normal conditions when using calcium-free dialyzate.

Analysis of Variance

Malabsorption of calcium and phosphate in chronic renal failure: 32P and 45Ca studies in dialysis patients.

A modified double-isotope method was used to determine the absorption of calcium and phosphate in patients with chronic renal failure. Eight hemodialysis patients and six healthy control subjects received an intravenous dose of 45calcium and 32phosphate and an oral tracer dose of 45Ca and 32P was administered two weeks later. Timed plasma samples were obtained on each occasion to determine fractional absorption rates and cumulative absorption of either tracer from both tracer sets with deconvolution analysis. Stool collections were analyzed. Calcium absorption in normal subjects peaked at 12% over fifteen minutes at one hour and declined rapidly thereafter. Absorption was essentially complete at four hours and cumulative absorption at this time was 72 +/- 6%. The pattern of phosphate absorption was similar and cumulative absorption at 4 hours was 80 +/- 3%. Calcium absorption in dialysis patients was significantly impaired with a flattened profile, a maximal 15-min absorption rate of 2% and cumulative 4-h absorption of 20 +/- 2%. Phosphate absorption in dialysis patients was also impaired to a comparable degree with a maximal rate of 3.6% and a more delayed cumulative total of 35 +/- 5%. Stool data showed good agreement with deconvolution analysis in volunteers but always overestimated absorption in patients. Sequential double isotope analysis provided a simple and convenient method for the concurrent estimation of calcium and phosphate absorption in humans.

Aged

Elective total parathyroidectomy without autotransplant in end-stage renal disease.

Ten patients are reported following parathyroidectomy (PTX). In 9 all identifiable parathyroid tissue in the neck was deliberately removed, and in the tenth (operated 14 years ago) the remnant which had been left probably did not function. Their post-operative course resembled that of patients treated conventionally, and their subsequent course was likewise uneventful with disappearance of all symptoms associated with their osteodystrophy. All patients required oral calcium supplementation but none were given vitamin D compounds after the initial period of repletion following surgery. Mean serum values were (before PTX and current) for calcium 2.63 +/- 0.14 and 2.33 +/- 0.08 mmol/liter, P = NS, for phosphorus 1.96 +/- 0.13 and 1.38 +/- 0.09 mmol/liter, P less than 0.01, and for alkaline phosphatase 713 +/- 191 and 101 +/- 14 IU, P less than 0.05. Evidence for residual parathyroid tissue was present in each case; one patient remained mildly hyperparathyroid and several were mildly hypoparathyroid by the IRMA PTH assay. Bone histomorphometry in five subjects post-PTX showed either normal or low turnover. Radiologically, striking remineralization was seen with disappearance of all erosive changes. We suggest that residual areas of parathyroid tissue are stimulated and continue to secrete hormone even when all the discrete glands have been removed. It is recommended that when indicated, and in the absence of aluminum excess, total PTX without autotransplant should be the preferred form of therapy for long-term dialysis patients.

Adult

Calcium-free dialyzate: development and applications.

A calcium-free, bicarbonate-containing concentrate was prepared for hemodialysis, which, after dilution, gave analyzed concentrations of sodium of 146 mmol/l, Cl 110 mmol/l, HCO3 of 35 mmol/l and pH of 8.3. When compared with standard bicarbonate dialysis, no important differences in blood chemistries, symptoms or signs were seen. The solution has been trouble-free in over 300 dialyses. Total amount of calcium lost uncorrected for time, dialyzer or blood flow was 40.6 +/- 1.1 mmol, n = 62. This loss was replaced by a calcium infusion into the venous line giving 40 mmol calcium over 4 h. The dialyzate calcium loss could be accurately predicted by sampling without collecting the total dialyzate volume. The uses of this concentrate for bicarbonate dialysis, citrate anticoagulation and avoidance of hypercalcemia in patients treated with oral calcium for phosphate binding is discussed.

Bicarbonates

Successful human double-lung transplantation after five and one-half hours of preservation.

Successful clinical double-lung transplantation after 5 1/2 hours of pulmonary ischemia is reported. Static hypothermic preservation with a high-volume, high flow rate-modified Collin's solution pulmonary artery flush was used. Excellent early and late pulmonary function demonstrates the efficacy of the technique that is described in detail. Lung transplantation remains limited by the lack of reliable methods of long-term storage of donor organs, but refinement of current techniques may soon allow its wider application.

Adult

Sporadic aluminum osteomalacia: identification of patients at risk.

Chronic dialysis patients at risk for aluminum osteomalacia in areas of low water-aluminum content are not well identified. We, therefore, studied retrospectively a cohort of 59 patients who underwent bone biopsy at two hospital-based dialysis centers in Montreal (water aluminum content less than 10 micrograms/L). Overall, 25% of patients biopsied had aluminum-related osteomalacia defined by aluminum staining of more than 30% of the trabecular surface and low levels of bone formation as measured by tetracycline labeling. Multiple linear regression analysis showed high predialysis serum creatinine (P less than .05) and the amount of aluminum prescribed per month (P less than .05) as the most important determinants of aluminum staining. We conclude that aluminum-related osteomalacia can be a frequent disease entity in areas of low water-aluminum content. Our findings also suggest predialysis serum creatinine and the amount of aluminum prescribed per month are risk factors for the development of aluminum-related osteomalacia. Though the relationship between serum creatinine and aluminum staining of trabecular bone is unclear, serum creatinine is probably a marker for adequacy of dialysis in these patients.

Aluminum

Direct functional assessment of human osteoblasts by radioautography: methodology and application in end stage renal disease.

Fragments approximately 1 mm3 of freshly obtained iliac crest cancellous bone were incubated for 30 minutes at 37 degrees C in Krebs buffer containing 3H-leucine or 3H-proline followed by radioautography. Grains per osteoblast, reflective of protein synthetic activity, were counted in normal controls and patients with end stage renal disease with or without significant aluminum storage in their bones. Compared with control the end stage renal disease patients without significant aluminum storage had more large osteoblasts with increased grain counts which were ascribed to secondary hyperparathyroidism. Cells from patients with greater than 30% surface aluminum had more small osteoblasts with grain counts intermediate between control and less than 2% aluminum, ascribed to an inhibitory effect of aluminum on the secondary hyperparathyroidism. Cell activity did not depend on location next to a tetracycline label or osteoid and it was suggested that all bone lining cells could be considered as osteoblasts. Aluminum storage was associated with impaired mineralisation in the presence of normal or increased osteoblastic protein synthetic activity suggesting that in these patients the mineralisation defect was not primarily due to an abnormality in osteoblast function.

Aluminum