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Biomedical subjects

Charles J Diskin

Publications and source records attributed to Charles J Diskin.

At least 19 recordsLinked to original sources

Effect of phosphate binders upon TSH and L-thyroxine dose in patients on thyroid replacement.

BACKGROUND: While calcium carbonate is known to interfere with the gastrointestinal absorption of levothyroxine, we hypothesized that other phosphate binders would also bind to levothyroxine and decrease bioavailability of levothyroxine in dialysis patients. METHODS: The records of 1,566 patients on hemodialysis who were being treated by the Hypertension, Nephrology, Dialysis, and Transplantation Center (the regional renal referral center for Eastern Alabama, USA) were evaluated. The type of phosphate binder and amount were then correlated (two-tailed Pearson Correlation) to TSH levels, serum phosphorus and the amount of levothyroxine taken. Friedman Test and Wilcoxon Signed Ranks Test were performed to analyze the significance of difference in thyroxine dosing and TSH levels between the different phosphate binders. RESULTS: Sixty-seven patients were identified who were taking levothyroxine while taking three different kinds of phosphate binders; namely, calcium carbonate, calcium acetate, and sevelamer HCl. We found that the TSH levels of patients on calcium carbonate (P = 0.002) and sevelamer HCl (P = 0.033) were significantly higher than patients on calcium acetate with the difference increasing with time on each binder. Sevelamer was also found to be associated with significantly higher dosing requirement of thyroid replacement than those on either calcium carbonate or calcium acetate (Z = -3.17, P = 0.001). CONCLUSION: Sevelamer (but not calcium acetate) in addition to calcium carbonate appears to interfere with the bioavailability of levothyroxine.

Acetates↗

Does the hyperfiltration of minoxidil result in increased proteinuria and loss of renoprotection conferred by angiotensin inhibition?

The objective of the present study was to retrospectively examine whether the addition of minoxidil to patients who were already treated with maximum doses of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers but who had not achieved target blood pressures, has any detrimental effect on proteinuria or renal function or whether its effect on blood pressure prove salutary. The clinical records of the patients seen at the Hypertension, Nephrology, Dialysis and Transplantation Clinic from June 1982 through May 2005 were reviewed to identify 54 patients (78% men, 82% African-American) who had taken minoxidil (with and without angiotensin inhibition and blockade) and who had documented 24-hour urines for creatinine clearance and quantification of proteinuria before the initiation of minoxidil and after the blood pressure had stabilized on its final dose. The study was done at the Hypertension, Nephrology, Dialysis and Transplantation Clinic, the regional referral center for renal problems in eastern Alabama, USA. Minoxidil, whether alone or in combination with maximum doses of ACEIs and ARBs, was very successful in reduction of mean arterial pressure, but there was a tendency towards an increase in proteinuria. When minoxidil was given alone, patients demonstrated a trend towards reduction of proteinuria associated with blood pressure reduction; however, when minoxidil was added after the maximal doses of ACEIs and ARBs had been reached there was a significant increase in proteinuria (p = 0.017) on paired comparison in the same patients whose proteinuria had already demonstrated a significant decrease (p = 0.02) on the ACEI and ARB alone despite further significant reduction of blood pressure with the minoxidil (p = 0.003). Renal function deterioration to end stage renal disease correlated with increase in proteinuria (p = 0.03). We conclude that minoxidil was very effective in lowering systemic blood pressure but when given to patients already on maximum doses of ACEI and ARBs, there was an increase in proteinuria which could be interpreted as a detrimental effect having in mind that the blood pressure was significantly lowered.

Angiotensin II Type 1 Receptor Blockers↗

Recurrent metabolic alkalosis and elevated troponins after crack cocaine use in a hemodialysis patient.

When acid-base disorders have been described after cocaine use, they are usually metabolic acidosis. We report a case of recurrent crack cocaine use associated with severe metabolic alkalosis on two successive admissions, in a patient in renal failure on hemodialysis and with minimal urine output, despite no history of vomiting or alkali ingestion. The metabolic alkalosis did not recur after counseling and abstention from cocaine.

Acidosis↗

Removal of methotrexate by peritoneal dialysis and hemodialysis in a single patient with end-stage renal disease.

BACKGROUND: Although methotrexate is highly bound to albumin, it is thought to be removed by hemodialysis and not by peritoneal dialysis. We are not aware of any direct comparison in the same patient. CASE REPORT/METHODS: A 60-year-old patient on continuous ambulatory peritoneal dialysis was admitted to the East Alabama Medical Center for stomatitis and pancytopenia after being given 10 mg of methotrexate for his rheumatoid arthritis. Measurements of total methotrexate levels were made before, during, and after sequential peritoneal and hemodialysis treatments. RESULTS: We found that the clearance of methotrexate measured in the dialysate was equal in the first hour of dialysis for both types of dialysis, although serum levels were markedly lower in hemodialysis compared to peritoneal dialysis. CONCLUSION: Methotrexate was cleared by peritoneal dialysis in the first hour of an exchange and was not associated with a rebound in serum levels. Hemodialysis was associated with lower serum levels; however, there was also a significant rebound 2 hours after the procedure ended. Since neither procedure was able to preclude the death of the patient, other more effective means of methotrexate elimination should be employed.

Arthritis, Rheumatoid↗

Can acidosis and hyperphosphataemia result in increased erythropoietin dosing in haemodialysis patients?

AIM: To evaluate whether factors such as acidosis and hyperphosphataemia that might cause an increased oxygen delivery to tissues could result in increased dosing requirements for intravenous erythropoietin (EPO) administration given to haemodialysis patients. METHODS: The clinical records of the patients seen at the Hypertension, Nephrology, Dialysis and Transplantation Clinic from December, 2004 through August, 2005 were reviewed to identify patients who had taken intravenous erythropoietin. Two-tailed, Pearson's correlation was performed to determine correlations between any of the parameters. Analysis of variance and stepwise regression for covariance were used to evaluate the relations of demographic and clinical characteristics and laboratory variables. Analysis of covariance and K means cluster analyses were also performed to examine linkage between variables. Kendall's Tau correlation was used for correlations of non-parametric data. RESULTS: There was a significant direct or positive correlation at the 0.01 levels between dry weight, age, intact parathyroid hormone level (PTH), and serum phosphorus and EPO dose. There was an inverse or negative correlation at that level between the serum bicarbonate and urea reduction ratio (URR) with the EPO dose at the same level while there was a weaker correlation but direct correlation between the white blood count (WBC) and EPO dose. There was significant colinearity between serum phosphorus and PTH but serum phosphorus showed a more significant correlation with EPO overall. Stepwise regression analysis for covariance revealed that phosphorus remained significantly correlated with EPO resistance after the removal of the effect of PTH while PTH lost its significance after the effect of phosphorus was removed. CONCLUSION: Acidosis and hyperphosphataemia are associated with apparent increased erythropoietin dosing requirements. While this study did not evaluate the mechanism of such requirements and indeed many mechanisms might be possible, a rightward shift in the oxygen-haemoglobin dissociation curve resulting in down-regulation of erythropoietin receptors is considered consistent with the data and present knowledge.

Acidosis, Renal Tubular↗