PubMed Health⌕ Search

Biomedical subjects

J I Shapiro

Publications and source records attributed to J I Shapiro.

76 records · Page 5Linked to original sources
PubMed1985

The effect of verapamil on renal function after warm and cold ischemia in the isolated perfused rat kidney.

The potential usefulness of verapamil, a calcium channel blocker to renal allograft preservation, was investigated using the isolated perfused rat kidney. Two models of ischemic injury were used. In the first model, rat kidneys were exposed to 40 min of 37 degrees C ischemia on the perfusion circuit. Addition of verapamil in doses of 2.5, 5, and 100 microM concentration to the perfusate significantly improved inulin clearance (Cin) and total sodium absorption (TNa) in the hour of reperfusion following ischemia. Regeneration of adenosine triphosphate (ATP) and total adenine nucleotide TAN levels during reperfusion following warm ischemia were also significantly higher in verapamil-treated kidneys. In the second model, rat kidneys were flushed in situ with Collins C2 solution and stored at 0 degrees C for 8 hr. After this period of cold ischemia, they were perfused on a perfusion circuit with perfusion media. Verapamil 2.5 microM was absent from both flush and perfusate (control), or added to just the flush, both the flush and perfusate, or just the perfusate. Addition of verapamil to the flush or the flush and perfusate significantly improved Cin, urine flow rate (V) and TNa during reperfusion, compared with control. Addition of verapamil to just the perfusate did not effect Cin, TNa, or V but did significantly increase RPF. These findings suggest the verapamil may protect against organ damage occurring during both warm and cold ischemia in the absence of any systemic effects and thus may be useful for renal allograft preservation.

Adenine Nucleotides↗
PubMedDate not supplied

Magnetic resonance study of renal transplantation.

In the last few years, we have focused our research effort on the magnetic resonance spectroscopic (NMR) studies of organ transplantation in the rat. P-31 NMR was employed to study changes in high-energy phosphates, intracellular pH in vivo of transplanted kidneys either during normal function, while undergoing the rejection process or subjected to other insults (e.g. ischemia, cyclosporine nephrotoxicity, urinary obstruction) which may also cause graft dysfunction. Nuclear magnetic resonance (NMR) parameters, specifically relative peak areas and intracellular pH, accurately distinguished among the different causes of graft dysfunction. Ureteral obstruction was clearly identified by elevations in the phosphodiester/urine phosphate peak. Ischemia and rejection were both associated with increases in inorganic phosphates and phosphomonesters and decreases in the beta-phosphate peak of adenosine triphosphate but were distinguishable from each other by differences in intracellular pH which was normal in rejected allografts (7.33 +/- 0.07, n = 3) and low in ischemic allografts (7.00 +/- 0.05, n = 3, p less than 0.05). Grafts insulted with cyclosporine toxicity were not distinguishable from normal allografts by any of the parameters studied. To determine the temporal relationship of NMR changes in allograft rejection, similar studies were performed serially in a group of rejecting (R) kidneys (n = 7) and compared with a control group of nonrejecting (NR) kidneys (n = 7). Major decrease in adenosine triphosphate (ATP) with increases in Pi and a marked increase in the Pi/ATP ratio were noted in the R allografts over time. The R allografts could be completely segregated from the NR allografts on the basis of the Pi/ATP ratio by day 7. These data suggest that 31P NMR spectroscopy may have potential clinical application in differentiating among the causes of graft failure of human renal allografts.

Adenosine Triphosphate↗
PubMedDate not supplied

Acute renal failure. Recognition and prevention.

Acute renal failure remains a devastating syndrome associated with a high mortality rate. Accurate and rapid etiologic diagnosis is critical, since it may be possible to stop the injurious process and prevent further progression of renal insufficiency. To do this, one must understand and differentiate among the three broad categories of disorders that can cause acute renal failure-prerenal, postrenal, and intrarenal processes. This article compares and contrasts these three categories in regard to causes and predisposing factors, history and physical examination, urinalysis, and urine chemistries. Treatment focuses on correcting prerenal and postrenal factors; treating acute complications, such as hyperkalemia, hyponatremia, acidosis, and pulmonary edema; optimizing cardiac output and renal blood flow; and adjusting doses of drugs consistent with renal failure.

Acute Kidney Injury↗