Lactobacillus allograft pyelonephritis and bacteremia.
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Biomedical subjects
Publications and source records attributed to R Dunlay.
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Statin-fibrate combinations are commonly used to treat hyperlipidemia. These drugs have been previously reported to cause rhabdomyolysis with acute renal failure. Whether different statin-fibrate combinations have different risks for rhabdomyolysis is not known. We report a patient who developed rhabdomyolysis with acute renal failure promptly after switching from the combination of pravastatin and fenofibrate to simvastatin and gemfibrozil.
Parathyroid function was studied in three different histological forms of renal osteodystrophy: osteitis fibrosa (OF), low-turnover aluminium-associated bone disease (LTAABD), and aplastic bone disease without aluminium (ABD). Parathyroid function was determined by the evaluation of the sigmoidal parathyroid hormone-(PTH)-calcium curve, which was obtained by the performance of a reduced calcium and an increased calcium haemodialysis. Parameters of the sigmoidal PTH-calcium curve evaluated included maximally stimulated (PTHMax) and inhibited (PTHMin) PTH, the set point of calcium for PTH (ICA50), defined as the ionised calcium concentration at which PTHMax was reduced by 50%, the ratio of basal PTH to maximally stimulated PTH (PTHBase:PTHMax), the ionised calcium concentration at which basal (ICABase), maximally stimulated (ICAMax), and maximally inhibited (ICAMin) PTH values were observed, and the slope of the PTH-calcium curve. Both PTHMax and PTHMin were greater in OF than the other two groups (P less than 0.02). The ratio of basal to maximally stimulated PTH was greater (P less than 0.02) in OF (61 +/- 7%) than LTAABD (33 +/- 5%) and ABD (36 +/- 7%). The ICA50 and the ICAMax were greater (P less than 0.03) in OF than the other two groups; however, no differences were observed in the ICABase and ICAMin. The slope of the PTH-calcium curve (% maximal PTH), which should indicate the sensitivity of parathyroid cells, was greater in OF than LTAABD (P less than 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)
The parathyroid hormone (PTH) receptor is coupled via a guanine nucleotide-binding regulatory protein (G protein) to phospholipase C (PLC). Binding of PTH to its receptor leads to activation of PLC with the subsequent hydrolysis of phosphatidylinositol 4,5-bisphosphate to inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). IP3 generation leads to the release of intracellular calcium stores, which produces an increase in the intracellular calcium concentration. DAG activates protein kinase C (PKC). Both IP3 metabolites and PKC may play a role in returning the intracellular calcium concentration back to base line, by stimulating the movement of calcium from the intracellular to the extracellular compartment, as well as by sequestering calcium within intracellular organelles. PKC appears to be important in the development of desensitization and downregulation of the PTH receptor to PTH. Activation of PLC may be important in modulating the well-known effects of PTH on bone and kidney and also may be relevant to recently described actions, such as the possible role of PTH as a growth factor in skeletal tissue. Important issues that need to be addressed in this field include 1) characterization of the PTH receptor, 2) the possible role of low-molecular-weight G proteins in PTH signal transduction, and 3) further description of the role of alternate pathway signal transduction in producing the effects of PTH.
A two-needle method for calculating recirculation was compared with the standard three-needle method, substituting the standard phlebotomy of a remote vessel during dialysis with blood obtained from the dialyzer inlet needle 15 minutes after the termination of dialysis. Twenty patients were studied prospectively. There was no significant difference between corrected blood flow calculated with the standard and two-needle methods. The BUN obtained from the inlet line needle 15 minutes after conclusion of the treatment did not differ significantly from the BUN concentration in the specimen from a contralateral arm drawn five minutes before termination of dialysis. Recirculation calculated by the two-needle method correlated well with the results obtained with the standard three-needle method. The two-needle method provides a convenient alternative to the standard three-needle method of determining recirculation.
STUDY OBJECTIVE: To determine the efficacy and safety of nebulized albuterol in the acute treatment of hyperkalemia in patients on chronic hemodialysis. DESIGN: Prospective, double-blind, and placebo-controlled study. SETTING: Outpatient hemodialysis clinic at a university medical center. PATIENTS: Ten patients on maintenance hemodialysis who had chronic hyperkalemia. INTERVENTIONS: Patients received nebulized albuterol therapy (10 mg or 20 mg) or placebo (saline) on three separate occasions, serial measurements of plasma potassium levels, blood pressure, and pulse were then taken for a 2-hour period. MEASUREMENTS AND MAIN RESULT: Patients had a significant decrease in plasma potassium concentrations that was evident by 30 minutes and sustained for at least 2 hours after albuterol treatment. After the administration of 10- and 20-mg doses of albuterol, the maximal decrease in the plasma potassium levels was 0.62 +/- 0.09 and 0.98 +/- 0.14 mmol/L (SE), respectively. Nebulized saline administration did not produce a significant change in the plasma potassium concentrations. Patients did not develop symptoms or significant changes in blood pressure or heart rate with albuterol treatment. CONCLUSIONS: In the doses used, nebulized albuterol therapy resulted in a prompt and significant decrease in the plasma potassium concentrations in patients on hemodialysis, and caused no adverse cardiovascular effects. This treatment should be considered as an important adjunct for acute treatment of serious hyperkalemia in this population of patients.
The effect of intravenous calcitriol on parathyroid function was evaluated in nine chronic hemodialysis patients with secondary hyperparathyroidism. Two micrograms of calcitriol were administered intravenously after dialysis thrice weekly for ten weeks. Parathyroid function was assessed by inducing hypo- and hypercalcemia with low calcium (1.0 mEq/liter) and high calcium (4.0 mEq/liter) dialyses before and after ten weeks of intravenous calcitriol therapy. To avoid hypercalcemia during calcitriol administration, the dialysate calcium was reduced to 2.5 mEq/liter. Parathyroid hormone (PTH) values (pg/ml) from dialysis-induced hypo- and hypercalcemia were plotted against serum ionized calcium, and the sigmoidal relationship between PTH and calcium was evaluated. Basal PTH levels fell from 902 +/- 126 pg/ml to 466 +/- 152 pg/ml (P less than 0.01) after therapy without a significant change in the serum total calcium concentration. The ionized calcium-PTH sigmoidal curve shifted to the left and downward after calcitriol therapy. The maximal PTH response during hypocalcemia decreased after calcitriol from 1661 +/- 485 pg/ml before calcitriol to 1031 +/- 280 pg/ml afterward (P less than 0.05). The PTH level at maximal inhibition due to hypercalcemia decreased from 281 +/- 76 pg/ml before calcitriol to 192 +/- 48 pg/ml afterward (P less than 0.05). The slope of the sigmoidal curve changed from -2125 +/- 487 to -1563 +/- 385 (P less than 0.05). The set point of ionized calcium (4.60 +/- .11 mg/dl before vs. 4.44 +/- .07 mg/dl after) did not change significantly with calcitriol therapy.(ABSTRACT TRUNCATED AT 250 WORDS)