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Biomedical subjects

S Kobrin

Publications and source records attributed to S Kobrin.

17 recordsLinked to original sources
PubMed2001

Dramatic recovery of renal function after 6 months of dialysis dependence following surgical correction of total renal artery occlusion in a solitary functioning kidney.

Revascularization of renal artery stenosis for the treatment of hypertension is an established procedure. In selected clinical scenarios, successful revascularization procedures may preserve or restore renal function. We present a 31-year-old man who underwent successful renal revascularization of a solitary functioning kidney after being dialysis dependent for approximately 190 days. He had dramatic improvement of renal function and has remained off dialysis since his surgery 18 months ago. He continues to have severe but controllable hypertension.

Acute Kidney Injury↗
PubMed2001

Preliminary observations of sildenafil treatment for erectile dysfunction in dialysis patients.

Erectile dysfunction is common in dialysis patients. We report our experience with sildenafil citrate in patients undergoing dialysis therapy. Male subjects attending the Outpatient Dialysis Unit at the University of Pennsylvania (Philadelphia, PA) who were prescribed sildenafil by their primary physician or nephrologist were asked to complete the International Index of Erectile Function before their first dose of sildenafil and after at least 4 weeks of therapy. Subjects' mean age was 50.3 +/- 14.63 (SD) years. Ninety-three percent of the subjects were black. Based on a global efficacy question, 66.7% of the subjects believed that treatment had improved their erections. Subjects reported no increase in the sexual desire domain despite experiencing a significant increase in erectile function, orgasmic function, and satisfaction with intercourse. Sildenafil was well tolerated in a selected group of patients who reported improved sexual function with no major adverse effects.

Adult↗
PubMed2000

Predictive performance study of two digoxin assays in subjects with various degrees of renal function.

This prospective study was conducted to compare the predictive performance of fluorescence polarization immunoassay (FPIA, Abbott TDx Digoxin II) and radioimmunoassay (RIA, Kallestad Labs) with combined low-pressure liquid chromatography/RIA (LPLC/RIA) digoxin assay in measuring 15-17 serum digoxin concentrations (SDC) obtained after a single 10 microg/kg intravenous digoxin dose in patients with various degrees of renal function and at different SDC ranges. Eighteen men and women were stratified into 3 age- and gender-matched groups based upon renal function [N = 6 in each, group I (Cl(cr) < 10 mL/min), group II (Cl(cr) = 10-50 mL/min), and group III (Cl(cr) > 50 mL/min)]. Serum digoxin concentrations were measured at time zero; at 0.25, 0.5, 0.75, 1, 2, 3, 4, 6, 8, and 12 hours; and at 2, 3, 4, and 5-7 days after the digoxin dose, using the three different digoxin assays. TDx Digoxin II was unbiased [mean error -0.09 (95% CI -0.19, 0.01)] and RIA biased [mean error -0.29 (95% CI -0.36, -0.21)] to over-predict SDC by 14.2%. In group I patients, the analysis revealed a bias to over-predict SDC by 6.0% for TDx Digoxin II [mean error -0.16 (95% CI -0.29, -0.07)] and an unbiased performance by RIA. In groups II and III, both TDx Digoxin II and RIA showed biased performance, the mean magnitude of bias was low (< 20%). For intermediate SDC range (> 0.5 ng/mL and < or = 3.0 ng/mL), TDx Digoxin II was unbiased in predicting SDC, whereas RIA was biased to under-predict SDC [mean error 0.13 (95% CI 0.10, 0.16)] by 9.9%. The magnitude of bias observed in all cases was less than 20%. Both assays, TDx Digoxin II and RIA, imprecisely measured SDC for all samples combined, different groups and SDC ranges. In all time-paired samples, TDx Digoxin II (FPIA) performed better than the RIA. In conclusion, the magnitude of bias observed with either assay at different groups and SDC ranges was not likely to be clinically relevant. Therefore, either assay may be used to measure SDC in clinical practice.

Anti-Arrhythmia Agents↗
PubMed1998

Outbreak of sterile peritonitis among continuous cycling peritoneal dialysis patients.

BACKGROUND: Approximately 30,000 patients receive peritoneal dialysis in the United States. In August 1996, several dialysis centers from different states reported sterile peritonitis among CCPD patients using sterile peritoneal dialysis solution (PDS) from a single manufacturer. The manufacturer recalled 53 lots of PDS that had passed established industry guidelines and Food and Drug Administration (FDA) approved quality control tests [including endotoxin levels <0.5 endotoxin units (EU)/ml], but had pre-sterilization bacterial colony counts >1 cfu/ml. METHODS: At one outpatient dialysis center, Hospital of the University of Pennsylvania (HUP), we conducted a retrospective cohort study of all CCPD patients treated during July 15 to August 30, 1996. A case-patient was defined as any HUP patient with culture-negative peritoneal fluid with a white blood cell count >100/mm3, cloudy peritoneal fluid, and/or abdominal pain. PDS and tubing were cultured for bacteria and assayed for endotoxin. RESULTS: Overall, 14 of 28 patients had sterile peritonitis. The only risk factor identified was exposure to > or =1 lot of recalled PDS (14 of 22 vs. 0/6, P = 0.02); the more recalled lots received, the higher the attack rate (P = 0.0001). Five of 47 PDS bags had detectable endotoxin; recalled lots were more likely to have measurable endotoxin than nonrecalled lots (5/19 vs. 0/17, P = 0.05). When case-patients resumed CCPD using PDS from non-recalled lots, no further cases were reported. CONCLUSIONS: Our results suggest that this outbreak was caused by intrinsic PDS contamination with endotoxin. Pre-sterilization colony counts may be an important quality control indicator for CCPD fluids in conjunction with endotoxin levels.

Adult↗
PubMed1998

Engagement of African American families in research on chronic illness: a multisystem recruitment approach.

Our multisystem approach addressed the recruitment of African American families with a chronically, physically ill member. The approach focused on the social transactions between the family, the healthcare team, and the research staff, and the influence of these transactions on family recruitment. This multisystem approach included three core strategies: defining the membership of families in a culturally appropriate fashion and engaging those members; engaging the healthcare team; and building and maintaining the skills and morale of the research staff. A description of a longitudinal family health study and potential sources of recruitment biases is provided. Descriptive and bivariate analyses examined the effectiveness of the recruitment approach. A focus groups explored the reciprocal process of family protectiveness that both facilitated and hindered family recruitment and the research staff's alliance with families and the dialysis staff. Discussion focuses on the family health study's recruitment rate, sampling biases, and methods for improving the effectiveness of the multisystem recruitment approach.

Adaptation, Psychological↗
PubMed1996

Staff security and work pressure: contrasting patterns of stability and change across five dialysis units.

Differences among clinical care units in social dynamics and social organization are associated with differences in the clinical course of patients with a range of chronic illness. These differences are also associated with well-being of staff members. Recent attention has focused on understanding these differences among units with an eye towards correcting deficiencies and enhancing strengths of clinical care units. The current study sought to delineate the effect of social and organizational dynamics unique to each unit on staff perceptions of the security of their relationships with other staff and their perceived work pressure. The unit as a major source of differences among staff subjects was compared with the impact of ethnic identity, of work in the morning shift vs other shifts, and of professional role. Results confirmed that unit membership was, by far, the most important correlate of staff perceptions of the unit, particularly those concerning security of relationships with others and perceived work pressure. Moreover, the results suggested that unit differences in perceived security were due to differences among units in long standing turmoil within the unit or long standing problematic ties between the unit and the larger institution which controls it. However, perceived work pressure seems more transient and may reflect the challenge of shorter-term fluctuations in the demands of patient care.

Adult↗
PubMed1996

Hemodialysis vascular access morbidity.

Complications associated with hemodialysis vascular access represent one of the most important sources of morbidity among ESRD patients in the United States today. In this study, new data on the magnitude and growth of vascular access-related hospitalization in the United States is presented, demonstrating that the costs of this morbidity will soon exceed $1 billion per yr. This study also reviews published literature on the morbidity associated specifically with native arteriovenous fistulae, polytetrafluoroethylene bridge grafts, and permanent central venous catheters. Next, new information on the changing patterns of vascular access type in the United States is presented, demonstrating the continuing evolution of medical practice away from the use of arteriovenous fistulae in favor of more reliance on synthetic bridge grafts. Based on these data, a discussion is provided of the tradeoffs among the most commonly available modalities of vascular access today. Although radial arteriovenous fistulae continue to represent the optimal access modality, the appropriate roles for brachial arteriovenous fistulae, synthetic bridge grafts, and central venous catheters are less certain because of inadequate data on the long-term function of the first and the high rates of complications associated with the latter two. To reduce vascular access-related morbidity, strategies must be developed not only to prevent and detect appropriately early synthetic vascular access dysfunction, but to better identify the patients in a whom radial arteriovenous fistula is a viable clinical option.

Age Factors↗
PubMed1995

The effect of renal function on serum levels of CA 125.

OBJECTIVE: Serum assays for CA 125 are used to monitor disease status in patients undergoing treatment for epithelial ovarian cancer. While a number of benign gynecologic as well as benign and malignant nongynecologic conditions are associated with CA 125 elevations, the established "normal" range describes a healthy population of women. The metabolism and clearance of CA 125 is not well understood. Because mild degrees of renal impairment frequently occur in ovarian cancer patients, we investigated the effect of impaired renal function on basal CA 125 in a population of female dialysis patients. METHODS: Twenty-five women on hemodialysis were selected at random. Patients ranged in age from 29 to 87 years. Renal disease was secondary in most cases to diabetes mellitus or hypertension. The creatinine clearance was less than 10 cc/min for all patients. The duration of dialysis ranged from 3 months to 14 years. Serum levels of CA 125 were measured using monoclonal antibodies in an immunoradiometric assay. RESULTS: The mean of duplicate determinations for 23 of 25 (92%) patients fell within the normal range for otherwise healthy women (< 35 U/ml). There was no apparent correlation between CA 125 level and age, menopausal status, BUN, serum creatinine, adequacy of dialysis, or primary underlying diagnosis. Of the 2 patients (8%) with CA 125 levels above the normal range, 1 was premenopausal and the other was postmenopausal; their CA 125 elevations were marginal (49.81 and 50.51). CONCLUSIONS: The results of this study demonstrate that even marked renal insufficiency is not itself associated with significant elevations of CA 125 above the normal range selected for otherwise healthy women. The development of renal insufficiency during treatment for ovarian cancer should not alter the interpretation of serum levels of CA 125.

Adult↗
PubMed1994

The effects of computer-tailored smoking cessation messages in family practice settings.

BACKGROUND: Many conventional health education materials, such as pamphlets and booklets, are designed to reach as wide an audience as possible; they are therefore often lengthy and contain information irrelevant to many consumers. Computer technologies allow sophisticated tailoring of messages targeted to individual patients and free of irrelevant information. METHODS: In two studies in North Carolina (study 1, N = 51; study 2, N = 197), adult cigarette smokers were identified from a cohort of family practice patients. Cigarette consumption, interest in quitting smoking, perceived benefits and barriers to quitting, and other characteristics relevant to smoking cessation were collected. Based on this information, smoking cessation letters were tailored by computer to individuals. Smokers were randomly assigned to experimental (tailored health letters) or comparison groups (generic health letter in study 1, no health letter in study 2). Smoking status was assessed again at 4 months (study 1) or 6 months (study 2). RESULTS: Both studies found statistically significant positive effects of tailored health letters among moderate to light smokers. In study 1, 30.7% reported quitting after 6 months vs 7.1% in the control group (P < .05); in study 2, 19.1% vs 7.3% (P < .05). CONCLUSIONS: Results from both studies indicate positive effects of computer-tailored smoking messages among moderate to light smokers. These findings are consistent with the focus of our computer-tailored program on psychological and behavioral factors related to smoking cessation. Smoking cessation outcomes may be enhanced by combining tailored messages with nicotine replacement therapies to treat physical dependency. Methods of tailoring health messages and incorporating the results into family practice are described.

Adult↗
PubMed1992

A controlled clinical trial of angiotensin-converting enzyme inhibition in type I diabetic nephropathy: study design and patient characteristics. The Collaborative Study Group.

A placebo-controlled, double-blind clinical trial has been initiated to determine whether angiotensin-converting enzyme inhibitor (ACEI) therapy with captopril (25 mg three times daily) slows the progressive loss of renal function in patients with type 1 diabetes mellitus. Entry criteria include; (1) ages 18 to 50 yr; (2) onset of insulin-dependent diabetes before the age of 30 yr, insulin dependent for at least 7 yr; (3) 24-h urine protein excretion > 500 mg, plus: (a) diabetic retinopathy or (b) if no retinopathy, a renal biopsy diagnosis of diabetic nephropathy; (4) serum creatinine (SCr) < 2.5 mg/dL; (5) informed consent. Patients follow strict medical management protocols. Systemic blood pressure is controlled to predefined goals (< 140-90 mm Hg). The primary outcome of the Study is a doubling of the patients' entry SCr to at least 2 mg/dL confirmed by a > 50% decrease in GFR by radioactive iothalamate clearance technique. Baseline characteristics of the cohort at entry into the Study are (mean +/- SD): male/female, 52%/48%; age, 35 +/- 8 yr; duration of diabetes, 21 +/- 7 yr; duration of proteinuria, 2.8 +/- 3.3 yr; duration of retinopathy, 4.5 +/- 4.1 yr; 50% of cohort presented with hypertension, duration, 4 +/- 4.7 yr; blood pressure, 139/86 +/- 19/12; SCr, 1.35 +/- 0.44 mg/dL; GFR 78 +/- 32 mL/min; BUN, 24 +/- 11 mg/dL; proteinuria, 3.1 +/- 3.3 g/day; cholesterol, 236 +/- 50 mg/dL; total glycosylated hemoglobin, 11.1 +/- 2.1%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Renal transplantation at the University of Pennsylvania Medical Center: an update of results in the cyclosporine era.

This chapter presents a summary of living-related, living-unrelated, and cadaver renal transplantation performed at the University of Pennsylvania Medical Center between January 1984 and October 1992. Over the past 9 years, 895 patients (557 males, 338 females, mean age 42 yrs) received 942 renal transplants; 599 patients received kidneys from cadaver donors (n = 627) and 296 patients received kidneys (n = 315) from living donors of all types. During this period, 151 patients were retransplanted, sometimes more than once (159 total retransplants, 124 secondary grafts, and 35 third or more transplants). An analysis of patient ant graft survival rates (calculated by actuarial methods) for different categories of transplant recipients was performed. Black recipients, as a racial subcategory, had the poorest graft outcome, especially when followed over the long term. Graft survival rates for Black recipients who were retransplanted with cadaver grafts were even worse and were noted to be similar to the diabetic population that received cadaver retransplants (66% vs 62% at 1 yr and 32% vs 25% at 5 yrs). Diabetic recipients of living-donor transplants had excellent graft survival results, similar to nondiabetic, living-donor recipients (patient survival rates 98% and 92% vs 97% and 92% at 1 and 5 yrs; graft survival rates 92% and 82% vs 92% and 82% at 1 and 5 yrs). HLA-identical recipients of first cadaver grafts demonstrated the best outcome in the entire cadaver series (graft survival rates 91% and 83% at 1 and 5 yrs, respectively). HLA-identical recipients of second or more cadaver grafts had poorer results than expected (50% graft survival at 1 yr) despite a 100% patient survival rate. HLA-identical recipients of living-related grafts had the best graft survival rates (96% at 1 yr and 94% at 5 yrs) and superior graft survival rates for retransplanted grafts as well (100% at 1 and 5 yrs). We conclude that in the last decade, patient and graft survival rates for cadaveric and living-donor renal transplants have improved dramatically relative to the results obtained in the pre-CsA era. Long-term graft survival in Black recipients remains lower than in other races, suggesting the need to analyze other factors to explain poorer graft survival in this recipient population. Results in diabetic recipients continue to be excellent at our center, encouraging the continuation of our aggressive approach to try to transplant diabetics as early as possible, particularly when a living donor is available.

Academic Medical Centers↗
PubMed1991

Systemic lupus erythematosus and the syndrome of inappropriate secretion of antidiuretic hormone.

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) has been reported rarely in systemic lupus erythematosus (SLE) with central nervous system disease. Previous case reports linking SIADH with lupus have either not documented clearly that SLE was the sole cause of the problem, or have not demonstrated a correlation between indicators of lupus activity and the onset and resolution of antidiuretic hormone secretion. We describe a case in which SLE was the sole contributor to the initiation of SIADH and where other evidence of lupus activity correlated temporally with inappropriate antidiuretic hormone secretion.

Dose-Response Relationship, Drug↗
PubMed1982

Chemistry and hypoglycemic activity of N-[[(Dialkylamino)alkoxy]phenyl]benzamidines.

A series of N-[[(dialkylamino)alkoxyl]phenyl]benzamidines was synthesized and evaluated for hypoglycemic activity in the glucose-primed rat. Structure-activity relationship indicated that N'-phenyl-N-[4-[2(diisopropylamino)-ethoxy]phenyl]benzamidine dihydrobromide (7), N'-(4-chlorophenyl)-N-[4-[2-(diisopropylamino)ethoxy]phenyl]-benzamidine dihydrochloride (31), and N'-phenyl-N-[4-[(diisopropylamino)propoxy]phenyl]benzamidine dihydrobromide (11) are some of the more interesting compounds. A comparison of these hypoglycemic agents with classical standards (tolazamide, phenformin, and buformin) in several experimental models showed that the benzamidines seem to combine in one molecule some of the biological activities of the beta-cytotrophic sulfonylureas and some of the activities of the biguanides.

Adrenalectomy↗
PubMed1981

Chemistry and hypoglycemic activity of benzimidoylpyrazoles.

A series of benzimidoylpyrazoles was synthesized and evaluated as hypoglycemic agents. Methyl 1-(N-cyclohexylbenzimidoyl)-5-methyl-3-pyrazolecarboxylate (13) and methyl 1-[N-(4-methoxyphenyl)benzimidoyl]-5-methyl-3-pyrazolecarboxylate (33) are two of the more interesting compounds. A comparison of these benzimidoylpyrazoles with classical standards (tolazamide, phenformin, and buformin) in several experimental models show that these compounds seem to combine in one molecule some of the biological activities of the beta-cytotrophic sulfonylureas and some of the activities of the biguanides. A synthetic scheme for the preparation of the benzimidolypyrazoles and a preliminary structure-activity relationship are presented.

Adrenalectomy↗
PubMedDate not supplied

Is the volume of distribution of digoxin reduced in patients with renal dysfunction? Determining digoxin pharmacokinetics by fluorescence polarization immunoassay.

STUDY OBJECTIVE: To determine digoxin pharmacokinetics in subjects with different degrees of renal function using fluorescence polarization immunoassay (FPIA), which is associated with less interference from digoxin-like immunoreactive substances (DLIS) than radioimmunoassay. SETTING: University hospital clinical research center. PARTICIPANTS: Eighteen subjects (mean age 44 yrs) with different degrees of renal function: group 1, creatinine clearance (Clcr) below 10 ml/minute; group 2, Clcr 10-50 ml/minute; and group 3, Clcr greater than 50 ml/minute (6 patients in each group). INTERVENTION: Over 5-7 days, 15 serum samples were collected after a single intravenous dose of digoxin 7 or 10 micrograms/kg actual body weight (WT) for serum concentration measurements by FPIA. Two-compartment pharmacokinetic parameters (zero-time intercept of the concentration-time curve of the initial distribution phase [A], zero-time intercept of the concentration-time curve of the terminal elimination phase [B], initial distribution phase constant [alpha], terminal elimination rate constant [beta], volume of distribution in the central compartment [Vc] and at steady state [Vss], total body clearance [Cl], mean residence time [MRT], area under the concentration-time curve [AUC]) were determined using a nonlinear least squares regression program. MEASUREMENTS AND MAIN RESULTS: No significant differences were found among groups for A, B, alpha, beta, beta-half-life Vc/WT, MRT, AUC, and Cl/WT. Significant differences were observed in Vss/WT (4.8 +/- 1.0, 6.6 +/- 0.5, 6.4 +/- 0.7 L/kg) between group 1 versus group 2 and group 1 versus group 3 (p < 0.01). Measured Clcr was correlated with Cl (r2 = 0.40, p < 0.01), Cl/WT (r2 = 0.29, p < 0.05), Vss (r2 = 0.35, p = 0.01), and Vss/WT (r2 = 0.24, p < 0.05). CONCLUSION: This study confirmed that Vss is smaller in patients with chronic renal failure (Clcr < 10 ml/min) than those without chronic renal failure. Therefore, previous recommendations that lower digoxin loading doses should be administered in patients with renal failure are applicable to digoxin serum concentration monitoring using FPIA.

Adolescent↗