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Biomedical subjects

S I Vas

Publications and source records attributed to S I Vas.

At least 55 records · Page 3Linked to original sources
PubMed1971

Effects of serum components on gram-negative bacteria during bactericidal reactions.

Biochemical changes which occur in a smooth strain of Escherichia coli were investigated with hyperimmune rabbit serum as a source of antibody and fresh normal guinea pig serum as a source of complement. Ribonucleic acid synthesis, as shown by incorporation of (3)H-uridine, was decreased as early as 5 min, and deoxyribonucleic acid synthesis, shown by incorporation of (3)H-thymidine, was decreased after 15 min of reaction. Incorporation of glycerol-2-(3)H into membrane lipid ceased after 25 to 30 min, probably as a result of functional or physical disruption of the membrane, or both. Permeability control (as indicated by loss of (3)H-uridine-labeled compounds and by decrease in optical density) and protein synthesis were subsequently shown to be affected after 30 min. The metabolic state of the bacteria was found to be important in determining the outcome of the reaction. This was shown by the influence of the type of medium on the reaction. A complex nutrient medium decreased susceptibility as compared with a simple medium. The energy sources glycerol and acetate also decreased susceptibility. It is postulated that the ability of the cell to prevent or repair damage to the cell membrane may be involved. Therefore, metabolic conditions which allow retention of vital processes associated with the cytoplasmic membrane and cell surface will mitigate the bactericidal effect. Such conditions may occur in vivo during bactericidal reactions.

Journal Article↗
PubMedDate not supplied

Update on continuous ambulatory peritoneal dialysis.

By now many patients have been successfully maintained on CAPD for five years or more, thus demonstrating that CAPD is a viable long-term treatment for end-stage renal disease. Peritonitis--the main concern of the earlier years--is now a less frightening complication. We know better how to treat peritonitis and its incidence has decreased from one episode every 8 months initially to one episode every 18 months now. In addition, several innovations, which have been or soon will be introduced, promise to decrease the frequency of peritonitis to an even lower rate. The problem of peritonitis is now being replaced by the chronic complications of CAPD, predominantly malnutrition and decrease in peritoneal ultrafiltration. CAPD has become an important adjunct in the treatment of children with ESRD, especially the very young. Even though not normal, their growth on CAPD is better than that of children on hemodialysis and as good as that after a successful transplant. CAPD has become a promising treatment for the diabetic with ESRD. This experience has stimulated interest and research in the role of intraperitoneal administration of insulin for blood glucose control. With the present worldwide experience of CAPD, this treatment has ceased to be experimental. A percentage of patients requiring dialysis will be better off on CAPD than on hemodialysis. Even though this percentage will vary among various countries, the nephrologist who wants to provide the best treatment for each patient must be well experienced in and have all treatments at his disposal including CAPD.

Adult↗
PubMedDate not supplied

The effect of small solute clearances on survival of anuric peritoneal dialysis patients.

OBJECTIVE: Primarily, to determine whether peritoneal small solute clearance is related to patient and technique survival among anuric peritoneal dialysis [continuous ambulatory (CAPD) and automated peritoneal dialysis (APD)] patients. A secondary goal was to describe the ability to attain Dialysis Outcomes Quality Initiative (DOQI) targets among anuric patients on peritoneal dialysis. DESIGN: Retrospective cohort study via chart reviews. SETTING: Peritoneal Dialysis Unit of Toronto Hospital (Western Division). PATIENTS: The study included 122 CAPD and APD patients between January 1992 and September 1997, with 24-hour urine volume less than 100 mL, or renal creatinine clearance (CCr) less than 1 mL/minute. Adequacy data were available for 115 patients. OUTCOME MEASURES: Mortality and technique failure (TF). Regression analysis was used to estimate the mortality and TF rate ratios (RR) for peritoneal Kt/V urea (pKt/V) and pCCr, adjusting for age, gender, diabetes, months of follow-up prior to anuria, albumin, transport status, coronary artery disease, cardiovascular disease, and peripheral vascular disease. RESULTS: Fifty seven per cent (51/89) of patients on CAPD and 81% (21/26) on APD had a weekly pKt/V > or = 2 and > or = 2.2, respectively (DOQI targets); whereas only 35% on CAPD (31/89) and 35% (9/26) on APD had a weekly pCCr > or = 60 U1.73 m2 and 66 L/1.73 m2, respectively. Median follow-up times among patients were 16.5 and 19.5 months pre- and postanuria, respectively. Patients with pKt/V > or = 1.85 experienced a strong decrease in patient mortality (RR = 0.54, p= 0.10); the effect was less pronounced for pCCr > or = 50 L/1.73 m2 (RR = 0.63, p = 0.25). No relationship was observed between pKt/V or pCCr and TF. CONCLUSION: Mortality was noticeably less frequent among patients with a pKt/V > or = 1.85 compared with those with a Kt/W < 1.85 (p = 0.10). Given the magnitude of the association, the failure to observe statistical significance relates to the size of the patient cohort. Our results imply that it is, in fact, possible to achieve DOQI targets among anuric patients on peritoneal dialysis.

Anuria↗
PubMedDate not supplied

Recurrence of hyperparathyroidism after total parathyroidectomy and autotransplantation in peritoneal dialysis patients.

OBJECTIVE: To evaluate the effectiveness of total parathyroidectomy (PTX) with autotransplantation in the treatment of secondary hyperparathyroidism (HPT), and to assess recurrence rate of HPT in this peritoneal dialysis (PD) population. DESIGN: A retrospective study in a single home PD unit. PATIENTS: Between 1994 and 1998, 19 of 574 patients on PD underwent PTX for treatment of secondary HPT. MAIN OUTCOME MEASURES: Clinical and biochemical improvement, recurrence of HPT, improvement in anemia post-PTX. RESULTS: Nineteen (3.3%) patients required PTX between 1994 and 1998. These 5 men and 14 women ranged in age from 22 to 66 years; they had been on maintenance PD pre-PTX for 47.5 +/- 38.1 months, and were followed for 26.1 +/- 15.5 months post-PTX. Sixteen patients had temporary hypocalcemia that was managed by oral (n = 10) or intravenous (n = 6) calcium supplements and calcitriol, while 3 patients had severe "hungry bone" syndrome postoperatively. One patient had recurrent laryngeal nerve palsy post-PTX. Bone pain disappeared in all 12 patients. Pruritus improved in 12/13 patients; fatigue improved in 15/16 patients. Comparison showed significant differences between hemoglobin and hematocrit values 1 month pre-PTX and 12 months post-PTX (p < 0.05). Parathyroid hormone (PTH) level in 15 (79%) patients returned to normal (< or = 7.6 pmol/L) during the first month post-PTX. In 5/12 (42%) patients, PTH level was < or = 7.6 pmol/L 2 years post-PTX, while in 2/12 (17%), PTH was > 22.8 pmol/L (three times normal) 2 years post-PTX, and 3/5 (60%) patients had a PTH > 22.8 pmol/L 3 years post-PTX. CONCLUSIONS: Total PTX with autotransplantation is associated with a tendency for recurrence of HPT. Our findings suggest that total PTX with autotransplantation may be an ineffective procedure in controlling HPT over the long term.

Adult↗