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Biomedical subjects

N W Levin

Publications and source records attributed to N W Levin.

At least 127 records · Page 7Linked to original sources
PubMed1983

Effect of cooled dialysate on serum catecholamines and blood pressure stability.

In the current study dialysis at 34 degrees C resulted in improved vascular stability in a group of patients who developed hypotension on conventional dialysis at 37 degrees C. Side effects of dialysate cooling were not noteworthy. The stability of blood pressure during cool dialysis may at least in part be due to an increase in plasma norepinephrine concentrations not observed during warm dialysis. Although pathogenesis of dialysis induced hypotension has not been clearly elucidated, a reduced vasoconstrictor and catecholamine response may be an important mechanism.

Blood Pressure↗
PubMed1982

Genetic counseling in adult polycystic kidney disease.

We evaluated 22 patients with end-stage renal disease (ESRD) due to adult polycystic kidney disease (APKD) to assess their knowledge of the hereditary nature of the condition and to determine whether they received adequate genetic counseling. Patients were evaluated by means of a questionnaire and a review of their medical records. Only 5 of 22 (23%) knew their disorder was hereditary at the time of diagnosis, and in only 4 (18%) was genetic counseling suggested. In no instance had proband and spouse received genetic counseling together. Diagnostic studies of children at risk were rarely suggested. We also evaluated the children of 9 probands for APKD. Of 26 children evaluated, 17 had APKD (65%). Sixteen had no children at the time of testing. All but two of the 26 were less than 25 years old. Of the probands' children over 15 years of age, 55% knew the name of the condition in the family but only 9% knew they should be tested. Our study demonstrated inadequacy of genetic counseling and follow-up in this group of patients; we suggest that referral for counseling become a routine part of their management. Early diagnosis and effective counseling has the potential benefit for the individuals of making rational reproductive decisions appropriate for their situation. Counseling may have to be repeated during the course of the patients' disease, as their perception of risk may change with time. With advances in dialysis and transplantation, ESRD may not be as devastating in years to come as it is now.

Adolescent↗
PubMed1982

Effects of early diabetes on uridine diphosphosugar synthesis in the rat renal cortex.

To assess the effects of streptozotocin-induced diabetes on the substrates utilized in the formation of glycoproteins, the pools of uridine 5'-diphosphoglucose (UDPG), uridine 5'-diphosphogalactose (UDP-GAL), uridine 5'-diphosphoglucuronic acid (UDPGA), and uridine 5'-diphospho N-acetyl galactosamine (UDPA-GAL) were measured in the renal cortex of control and over a 48-hr period in diabetic rats. In control rats these pools measured: UDPG, 256 +/- 23; UDP-GAL, 75 +/- 14; UDPGA, 147 +/- 16; UDPAG, 367 +/- 23; UDPG-GAL, 131 +/- 13 nmoles/mg DNA. In diabetic rats, except for UDP-GAL, all pools were increased 41 to 68%. The incorporation of radiolabeled orotate was increased in all pools, except UDP-GAL, in diabetic rats by 41 to 77% compared to control rats. The incorporation into UDPG and UDPAG was increased even after correction for the specific radioactivity of their immediate precursor, uridine 5'-triphosphate (UTP). Expansion of the UTP pool after orotate infusion was associated with an increase in the size of the UDPG and UDPAG pools in both control and diabetic rats. Depletion of the UTP pool after adenine infusion in controls was associated with a decrease in all pools. This study demonstrates that after the induction of diabetes there is a rapid increase in the bioavailability of substrates utilized in the synthesis of glycoproteins and glycosaminoglycans. It is theorized that this increase is necessary for the augmented synthesis of basement membrane-like material in the diabetic kidney.

Animals↗
PubMed1982

Psychosocial factors affecting adherence to medical regiments in a group of hemodialysis patients.

The present research was designed to identify psychosocial correlates of adherence among patients receiving hemodialysis at two outpatient clinics. The 116 participants were interviewed concerning their knowledge of treatment, health beliefs, treatment history, social support, personal characteristics, and adherence to the medication, diet and fluid-intake aspects of the regimen. In addition, medical record data were obtained on serum phosphorus and serum potassium levels, and on between-dialysis weight gains. The magnitude of relationships between predictors and adherence measures varied, depending on the method used to measure adherence. For the self-report measures, beliefs concerning the efficacy of the behavior and barriers to the behavior, along with reported family problems, proved to be consistent predictors. Other beliefs and characteristics did not contribute significantly. For the medical chart information, however, the predictive factors were less consistent. In general, situational factors seem to be the major contributors to patient adherence, and adherence itself is seen as a complex and multidimensional phenomenon.

Adult↗
PubMed1982

Long-term alternate day steroid therapy in renal transplantation. A controlled study.

Seventy-six adult renal allograft recipients were allocated 5 months post-transplantation to daily or alternate day maintenance methylprednisolone therapy. All 15 recipients of living related kidneys and 23 recipients of cadaver kidneys were placed on the alternate day regimen, while 38 patients with cadaveric grafts remained on daily methylprednisolone. In patients on alternate day methylprednisolone, serum creatinine concentrations, frequency of acute rejection episodes, and prevalence of chronic rejection were similar to those of patients on daily steroids. Furthermore, no differences were noted in the rate of loss of graft function between recipients of cadaver kidneys on daily versus alternate day steroids. There were no differences in body weight, blood pressure, degree of hyperglycemia, or hyperlipidemia between patients on the daily or alternate day schedules. However, the prevalence of clinical osteonecrosis and the rate of infectious complications requiring hospitalization were significantly decreased in patients on alternate day methylprednisolone. We conclude that alternate day methylprednisolone therapy is as effective as daily steroids for the maintenance of graft function in renal transplant recipients. The decreased incidence of osteonecrosis and the lower frequency of infectious complications represent a strong argument in favor of alternate day steroid therapy.

Adult↗
PubMed1982

Renal parenchymal disease: sonographic-histologic correlation.

A retrospective study of 109 patients who underwent renal biopsy was designed to correlate the sonographic appearance of the kidney with the histologic changes and clinical and laboratory findings in various renal parenchymal diseases. The clinical, pathologic, and sonographic data were analyzed blindly and independently by a team from each corresponding discipline. There was no correlation between the specific sonographic appearance and the type of renal disease. There was a significant correlation between renal length and the prevalence of global sclerosis, focal tubular atrophy, and the number of hyaline casts per glomerulus. A significant positive correlation was also found between cortical echogenicity and the severity of global sclerosis, focal tubular atrophy, the number of hyaline casts per glomerulus, and focal leukocytic infiltration. While there was overall significant correlation between the degree of cortical echogenicity and blood urea nitrogen and creatinine concentrations in each group, a wide range of variance was present. It is not currently feasible to distinguish different types of renal medical disorders using diagnostic ultrasound.

Adolescent↗
PubMed1981

Intervention strategies to improve compliance with medical regimens by ambulatory hemodialysis patients.

This research examined the relative efficacies of three intervention strategies designed to increase compliance to medical regimens in a group of ambulatory hemodialysis patients. The interventions examined included behavioral contracting (with or without the involvement of a family member or friend) and weekly telephone contacts with patients. Compliance was assessed with regard to following dietary restrictions and limiting fluid intake. Data were collected from 116 patients drawn from two outpatient clinics. Within clinics, patients were randomly assigned either to an intervention program or to a control group. The study employed a pretest-posttest control group design. Patients were interviewed before the intervention programs began (T1), after a 6-week intervention period (T2), and 3 months after completion of the intervention period (T3). Results showed that the interventions achieved substantial reductions in patients' serum potassium levels and in weight gains between dialysis treatments between T1 and T2. In general, however, these program effects tapered off to preintervention levels between T2 and T3. The findings thus indicate a need for long-term intervention programs.

Attitude to Health↗
PubMed1981

Alterations in glomerular RNA in diabetic rats: roles of glucagon and insulin.

Incorporation in vivo of labeled orotate into RNA and total nucleotides was measured in isolated glomeruli and whole renal cortex. In 2-day diabetic animals, glomerular RNA was increased, and there was greater incorporation of orotate into total nucleotides and RNA as compared with controls. Insulin reversed the exaggerated incorporation at infusion rates that corrected hyperglucagonemia without reducing plasma glucose and with only minimal changes in insulin concentrations. The addition of glucagon to insulin infusions reproduced the increased incorporation observed in untreated diabetics. Similar changes occurred in renal cortex, where differences in orotate incorporation into nucleotide precursors seemed to be the main cause for alterations in RNA labeling. Isotope incorporation in glomeruli correlated positively with plasma glucagon, but not with insulin or glucose concentrations. Although in 7-month diabetic animals orotate incorporation into RNA was less than in controls, probably as a consequence of renal disease, 24-hour insulin infusion decreased it further. Our results confirm that in the diabetic kidney, abnormal uracil nucleotide metabolism and increased cellular content of RNA are demonstrable in glomeruli as in the renal cortex. These changes appear to be related directly to hyperglucagonemia.

Adenine↗
PubMed1980

Phosphoribosylpyrophosphate bioavailability in diabetic rat renal cortex in vivo.

Experimental diabetes induces increased content of RNA and UTP in the renal cortex. Studies were designed to assess the bioavailability of 5-phosphoribosyl-1-pyrophosphate (PRPP) in the diabetic renal cortex because PRPP is an important determinant of the de novo synthesis of nucleotides. The tissue bioavailability of PRPP determines the effects of orotate or adenine administration on UTP, ATP, and GTP content and on the incorporation of labeled precursors into UTP and ATP. Diabetic and control rats with chronic intravenous cannulas were infused over 2.5-24 h with orotate or adenine. Orotate administration induced greater decreases in ATP and GTP and in labeled adenine incorporation into ATP concomitant with smaller increases in UTP in controls than in diabetic animals. Adenine administration induced a greater decrease of labeled orotate incorporation into UTP and a smaller increase in ATP in controls than in diabetic animals. Prolonging the adenine infusion resulted in disappearance of these differences. The results are compatible with greater initial bioavailability of PRPP in the diabetic renal cortex than in controls but with a rate of maximal PRPP generation that is the same in both tissues.

Adenine↗