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Biomedical subjects

S I Vas

Publications and source records attributed to S I Vas.

At least 37 records · Page 2Linked to original sources
PubMed1986

In vitro cytotoxicity and antibiotic activity of polymyxin B nonapeptide.

Polymyxin B nonapeptide, prepared by enzymic removal of the fatty acyl diaminobutyric acid side chain from polymyxin B, was about 100-fold less toxic to K562 cells than polymyxin B. MICs of polymyxin B nonapeptide against a test panel of bacteria were 2- to 64-fold lower than those of polymyxin B.

Bacteria↗
PubMed1985

Microbiological diagnosis of peritonitis in patients on continuous ambulatory peritoneal dialysis.

The fast and accurate etiological diagnosis of peritonitis in patients on continuous ambulatory peritoneal dialysis is essential. The concentration of larger volumes of peritoneal fluids may yield more isolates than conventional methods. The removal of antibiotics present in the fluids as a consequence of therapy by washing or using antibiotic-removing resins increases the yield considerably. The use of anaerobic culture media is justified if fecal organisms are suspected as the cause of the infection.

Bacteriological Techniques↗
PubMed1984

Continuous ambulatory peritoneal dialysis: no longer experimental.

Many patients with end-stage renal disease have now been maintained for 5 years or more with continuous ambulatory peritoneal dialysis (CAPD). Viewed initially as an experimental alternative to be used only when hemodialysis was not feasible, CAPD is now seen as the treatment of choice in an increasing number of situations. CAPD is suitable for self-care. The main concern in the early years--peritonitis--is now less frightening and less frequent (one episode occurring every 18 patient-months as compared with every 8 initially), and this has allowed chronic complications of CAPD, such as malnutrition and loss of the peritoneum's capacity for ultrafiltration, to come to light. As would be expected, among patients of advanced age and those who have heart disease or diabetes, survival rates tend to be lower than among other CAPD patients. However, hypertension seems to be more easily controlled, pre-existing anemia can be significantly ameliorated, and young children grow more normally than they do with hemodialysis. Diabetes-related changes in vision stabilize in most CAPD patients, and control of the blood glucose level is good; insulin is administered intraperitoneally. CAPD is thus showing itself to be a feasible form of long-term treatment for end-stage renal disease.

Adolescent↗
PubMed1983

Hepatitis B and the dental profession: response to hepatitis B vaccine in Canadian dental personnel. A study by the Canadian Red Cross Collaborative Group.

Reports from North America and Western Europe based on the prevalence of hepatitis B virus markers and frequency of hepatitis B in dentists indicate that this professional group is at increased risk of HBV infection. We gave hepatitis B vaccine (Merck Sharp and Dohme) to 251 dental students and faculty/staff members at faculties of dentistry in three Canadian universities. Participants received three 20 micrograms doses of vaccine, at 0, 1 and 5.5 months. Anti-HBs was detected in 42.9 per cent of persons after the first dose of vaccine, in 96.8 per cent after the second dose and in 99.6 per cent after the third dose. A follow-up of 150 persons 22 months after the first dose of vaccine indicated that high or medium levels of anti-HBs were maintained in nearly 87 per cent of the participants and only six per cent had no detectable antibody. Female vaccinees in each age group developed anti-HBs more promptly, and more of them were in the high antibody-response range in comparison to male participants. There were no unacceptable reactions to the vaccine. Our favourable experience with this vaccine would support recommendations for its routine use among dental professionals in Canada and other countries where this group is at increased risk of HBV infection.

Adult↗
PubMed1983

Quantitation of macrophage activation.

Chemoluminescence is a sensitive and relatively easy method to quantitate macrophage activation. Cytotoxic assay as measured by 51Cr release from tumour target cells is more involved and less sensitive. Our experiments indicate that, depending on the mode of activation, different effector mechanisms are operational. Thus, macrophages activated with double stranded yeast RNA show good chemoluminescence but no cytotoxic response while thioglycollate activated macrophages show the reverse response.

Animals↗
PubMed1981

Effects of the composition of peritoneal dialysis fluid on chemiluminescence, phagocytosis, and bactericidal activity in vitro.

Commercial fluid used for peritoneal lavage in peritonitis and in peritoneal dialysis suppressed the activity of peripheral blood leukocytes as measured by chemiluminescence, phagocytosis, and bacterial killing. Suppression was found to be due to the low pH and high osmolality of the fluid. The pH was adjusted to noninhibitory levels in vivo within 30 min, whereas osmolality changes were less rapid and remained at inhibitory levels for fluids of high dextrose concentration (4.25%). Chemiluminescence was the most sensitive assay for inhibitory effects of pH and osmolality, as well as for urea and heparin. The metabolic waste product urea at levels normally found in dialysate and heparin at concentrations routinely added to fluid inhibited only chemiluminescence, whereas creatinine and added insulin were not inhibitory. High fluid volume also resulted in a decrease in efficiency of bacterial killing. These results suggest some changes to be made in the treatment of peritonitis and in peritoneal dialysis.

Blood Bactericidal Activity↗
PubMed1978

Comparison of "invasive" and "non-invasive" strains of Staphylococcus epidermidis by phage typing.

Seventy strains of coagulase-negative staphylococci isolated from blood of patients together with 41 strains of these bacteria isolated from the skin were typed by three different phage sets. Different percentages of phage typability by compared phage sets were found. Blood culture strains showed phage pattern Ph10/U14/U16 while other strains were of different phage patterns.

Bacteriophage Typing↗
PubMed1976

Effects of endotoxin on carbohydrate metabolism in inbred mice.

Effects of endotoxin on carbohydrate metabolism were studied in A/HeJ (endotoxin-sensitive) and C3H/HeJ (endotoxin-resistant) inbred mice. A/HeJ mice developed hypoglycemia within two hours after endotoxin injection, yet liver glycogen content did not differ from controls. Similarly treated C3H/HeJ mice did not develop significant hypoglycemia. Administration of glucagon to endotoxin-treated A/HeJ mice failed to elevate their blood glucose concentrations, while endotoxin-treated mice of the same strain did respond to dibutyryl cyclic AMP with a significant elevation of blood glucose. C3H/HeJ mice on the other hand responded to glucagon and dibutyryl cyclic AMP with elevated blood glucose. Endotoxin-treated C3H/HeJ but not A/HeJ mice were able to carry out gluconeogenesis induced by prednisolone, while both inbred strains showed active glycogenesis after administration of an exogenous glucose load. Administration of glucagon resulted in diminished liver glycogen concentrations in A/HeJ endotoxin-treated mice suggesting no impairment of glycogenolysis. The inability of endotoxin-treated A/HeJ mice to respond to glucagon could be due to impairment of gluconeogenesis. Although endotoxin interfered with the capacity of both inbred strains to respond to glucagon administration with elevation of liver cyclic AMP, the effect was significantly more severe in A/HeJ mice. The susceptibility of A/HeJ mice to the lethal effect of endotoxin may be related to the apparent sensitivity of carbohydrate metabolic pathways to disturbance by endotoxin.

Animals↗
PubMed1975

Effect of nonspecific stimulation on the defense mechanisms of inbred mice.

Acquired resistance to facultative intracellular parasites was investigated in C57BL/6J inbred mice susceptibe to Salmonella typhimurium but inherently resistant to Listeria monocytogenes and in A/J inbred mice which showed the reverse relationship. A/J but not C57BL/6J mice were protected against S. typhimurium challenge by S. typhimurium phenol vaccine, S. typhimurium purified RNA, or L. monocytogenes purified RNA. C57BL/6J but not A/J could be protected against L. monocytogenes challenge by L. monocytogenes phenol vaccine, S. typhimurium RNA, or L. monocytogenes RNA. Yeast RNA, calf thymus RNA, BCG and poly (I:C) protected A/J against Salmonella and C57BL/6J against Listeria challenge. Enumeration of viable organisms in the RNA and BCG-stimulated animals after challenge indicated that macrophage activation had probably taken place. The RNA-elicited protection was long lasting and waned after about 60 days. Enhanced resistance to S. typhimurium and L. monocytogenes can be stimulated by nonliving substances bearing no known antigenic relationship to the pathogen. Enhanced resistance is elicited only in the host with a background of inherent resistance to the specific pathogen.

Animals↗