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Biomedical subjects

M S Siskind

Publications and source records attributed to M S Siskind.

13 recordsLinked to original sources

The effect of dialyzer reprocessing on performance and beta 2-microglobulin removal using polysulfone membranes.

Increased biocompatibility and lower cost are the two major arguments favoring routine dialyzer reprocessing. The impact of longer-term reprocessing is critical to the practical use of polysulfone membranes (PMs), because of the possibility of decreasing efficiency and performance, especially in the removal of beta 2-microglobulin (beta 2M), a protein that has been implicated in the development of dialysis-associated amyloidosis (DDA). In this study, we examine urea clearance (Kd), urea mass transfer coefficient (h0), ultrafiltration coefficient (K(uf)), and percent removal of beta 2M up to 24 uses. The study involved 11 patients on hemodialysis for 5.27 +/- 4.6 years, with a mean age of 62.5 +/- 9.7 years and average run-time treatment of 2.78 +/- 0.3 hours. PMs were tested after being reprocessed manually using bleach and formaldehyde. The efficacy of the dialyzer was examined on uses 1, 5, 10, 15, 20, and 24, and the percent removal of beta 2M was determined except in the twentieth use and corrected for ultrafiltration. The Kd obtained through 24 uses showed no significant change, although h0 was significantly increased in the fifteenth use, and K(uf) was significantly increased in the 10th and 20th use (P < 0.05). The percent removal of beta 2M increased significantly from 44.1 +/- 2.8 (mean +/- SEM) in the first use to 59.4 +/- 2.19 (P < 0.05) in the 10th use, and 62.1 +/- 4.07 and 63.1 +/- 4.27 in the 15th and 24th uses, respectively (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Ciprofloxacin-induced granulomatous interstitial nephritis and localized elastolysis.

Ciprofloxacin is known to cause acute interstitial nephritis. We report the first case of ciprofloxacin-induced granulomatous interstitial nephritis and localized elastolysis. The patient presented with acute renal failure and skin lesions following a 14-day course of ciprofloxacin administered for cellulitis. The patient had symmetric, palm-sized, tender violaceous plaques on both axillae. The renal biopsy revealed granulomatous interstitial disease. A skin biopsy revealed an elastolytic process with histocytic infiltration and calcification. After discontinuing ciprofloxacin and starting a short course of steroid therapy, the skin lesion and renal function improved promptly. The nephritis relapsed after prednisone was discontinued and responded to a second course of steroid therapy. Ciprofloxacin, like penicillin, can cause granulomatous interstitial nephritis and elastolysis. A prolonged course of steroid therapy may be indicated in patients with ciprofloxacin-induced granulomatous interstitial nephritis to avoid early relapse.

Ciprofloxacin↗

Association of cyclosporin A with acquired cystic kidney disease of the native kidneys in renal transplant recipients.

Acquired cystic kidney disease (ACKD) is a common complication in patients treated with long-term dialysis. Previous studies performed prior to the cyclosporin A (CsA) era indicate that successful renal transplantation causes regression of ACKD. Little has been published, however, on the occurrence of ACKD in CsA-treated transplant recipients. We conducted a prospective sonographic study in 33 renal transplant recipients and 32 dialysis patients to evaluate the effect of CsA on ACKD in transplant recipients. Transplant recipients had a lower prevalence (39% vs. 56% in dialysis patients) and severity (smaller kidneys and lower cyst grades) of ACKD when compared with dialysis patients. Renal cell carcinoma was found in two dialysis patients. Using multiple regression analysis, we found that the use of CsA was significantly correlated with the presence of ACKD in transplant recipients (57% in CsA-treated vs. 8% in non-CsA-treated patients). We conclude that renal transplantation reduces the prevalence and severity of ACKD in the native kidneys; however, among transplant patients, CsA administration is associated with a greater prevalence of ACKD.

Adult↗

Isoniazid-induced neurotoxicity in chronic dialysis patients: report of three cases and a review of the literature.

This report describes an increased incidence of neurotoxic side effects secondary to isoniazid therapy in patients with end-stage renal disease. Toxicity was observed only in those patients receiving pyridoxine supplements of less than 100 mg/day. The increased sensitivity of the dialysis population to isoniazid neurotoxicity is predominantly due to abnormal metabolism of pyridoxine resulting in low serum levels of the active metabolite, pyridoxal phosphate. In addition, there is rapid clearance of pyridoxal phosphate by hemodialysis, resulting in a severer deficiency of this active metabolite. In order to prevent the neurotoxicity associated with isoniazid therapy, we recommend that 100 mg/day of pyridoxine be given as a supplement to hemodialysis patients requiring isoniazid therapy.

Aged↗

Effect of intradialytic parenteral nutrition on quality of life in hemodialysis patients.

The purpose of this study was to determine the effect of intradialytic parenteral nutrition (IDPN) on the quality of life of malnourished patients with end-stage renal disease on high-efficiency and high-flux hemodialysis therapy. Patients, who met the Medicare eligibility requirements for IDPN, were asked to fill out and extensive questionnaire covering several measures of quality of life prior to initiating and again after completing four months of IDPN therapy. Although the IDPN improved serum albumin levels significantly, aside from improved sleep patterns, no significant improvements in quality of life could be demonstrated. The mortality rate of these enrolled patients was as high as 28% within 4 months. We concluded that the limited amount of nutrition delivered over the course of a short dialysis session may not be enough to appreciably change the lives of our malnourished patients.

Female↗

Hyperlipidemia associated with alpha-mercaptopropionylglycine therapy for cystinuria.

Treatment of cystinuria with alpha-mercaptopropionylglycine has been associated with fewer side effects than traditional therapy with D-penicillamine. In this report, we describe a patient who developed hyperlipidemia secondary to alpha-mercaptoproprionylglycine therapy. This abnormality resolved after the therapy was discontinued and did not recur with lower dose therapy. Patients treated with alpha-mercaptoproprionylglycine should be monitored closely for the development of lipid abnormalities.

Adult↗

Postpartum hypercalcemia in a patient with medullary sponge kidneys.

Previous associations of primary hyperparathyroidism-induced hypercalcemia and medullary sponge kidney (MSK) have been reported. In this report, we describe a lactating woman MSK noted to be hypercalcemic throughout lactation, without evidence of hyperparathyroidism. After the baby was weaned, the serum calcium returned to normal. A bone biopsy performed while the patient was hypercalcemic was consistent with hyperparathyroidism, suggesting the presence of a parathyroid-like protein produced during lactation.

Adult↗

Regulation of cGMP production by intracellular alkalinization in cultured rat inner medullary collecting duct cells.

We evaluated the relationship between cell pH and cGMP production in cultured rat renal inner medullary collecting duct cells. The cGMP level, 21 +/- 6, was not different in control vs. alkalinized cells, 49 +/- 17 fmol/mg protein (p greater than 0.5). 10(-11) M atrial natriuretic peptide (ANF) enhanced cGMP production in alkalinized cells, 426 +/- 34 vs. 141 +/- 9*. Conversely, alkalinization inhibited 10(-4)M nitroprusside (SNP) induced cGMP formation, 29 +/- 9 vs. 332 +/- 67*. Phosphodiesterase inhibition abolished the difference in cGMP production by ANF but did not reverse the inhibitory effect of alkalinization on SNP induced cGMP production. In rat renal inner medullary collecting duct cells, cellular alkalinization plays a significant role in the regulation of guanylate cyclase mediated cGMP production. * = p less than 0.05).

Ammonium Chloride↗

Regulation of intracellular calcium by cell pH in vascular smooth muscle cells.

Intracellular calcium (Cai2+) and intracellular pH (pHi) are important regulators of a variety of intracellular processes. Cai2+ is a regulator of muscle contraction, but the role of pHi is unclear. The purpose of this study was to determine the effect of alterations of pHi on Cai2+. A7r5 vascular smooth muscle cells (VSMC) were grown to confluence on glass cover slips. Cai2+ was determined with the fluorescent probe fura-2 and pHi with 2,7-bis-carboxyethyl-5(6)-carboxy-fluorescein (BCECF). Alkalinization of the VSMC by exposure to 20 mM NH4Cl (delta pHi 0.41 +/- 0.07) resulted in a rise in Cai2+ from 99 +/- 8 to 146 +/- 13 nM (n = 5) in the presence of extracellular Ca2+ (Cao2+). In the absence of Cao2+, NH4Cl-induced alkalinization also resulted in a Cai2+ rise (delta Cai2+ = 26 +/- 4 nM, n = 5). Similar changes in Cai2+ were observed when cells were alkalinized by exposure to nigericin in a KCl buffer (pH 7.7). Neither 100 microM verapamil or 100 microM 8,8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate HCl (TMB-8) altered the alkaline-induced changes. After cellular Ca2+ stores were partially depleted by exposure to AVP in a Ca2+-free solution, subsequent cell alkalinization induced no changes in Cai2+. These results demonstrate that alkalinization of VSMCs leads to a rise in cytosolic Ca2+ via release of intracellular Ca2+ stores. The intracellular Ca2+ storage sites appear to be the same as those sites sensitive to AVP. Thus pHi may regulate Cai2+ and thereby play a role in the regulation of vascular smooth muscle tone.

Ammonium Chloride↗

Dialysis access via a right ventricular assist device.

In this report, we describe the successful utilization of an external right ventricular assist device as vascular access for hemodialysis and continuous arteriovenous hemodialysis in a critically ill patient on biventricular mechanical assist support. Utilization of the right ventricular assist device lines provided relatively easy and safe dialysis access and temporarily reduced the risks associated with the conventional vascular access techniques.

Heart Failure↗