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Biomedical subjects

R Irwin

Publications and source records attributed to R Irwin.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effects of modulators of the renin-angiotensin-aldosterone system on cough. Losartan Cough Study Group.

OBJECTIVE: To compare the incidence of cough in patients with a history of angiotensin converting enzyme (ACE) inhibitor-related cough who received losartan [a type 1 angiotensin II (Ang II) receptor antagonist], lisinopril (an ACE inhibitor) or hydrochlorothiazide (a diuretic). DESIGN: An international, multicentre, randomized double-blind, parallel-group controlled trial. SETTING: Outpatient clinics at 20 tertiary care medical centres in 11 countries. PATIENTS: One hundred and thirty-five patients with uncomplicated primary hypertension with a history of ACE inhibitor-related cough were randomly assigned to the double-blind treatment phase and completed the study. INTERVENTION: After confirming that the cough was ACE inhibitor-related by a single-blind rechallenge, followed by a placebo washout period, patients were randomly assigned to receive 50mg losartan, 20mg lisinopril or 25mg hydrochlorothiazide once a day for 8 weeks. MAIN OUTCOME MEASURES: Cough incidence, severity and frequency were assessed by a self-administered questionnaire and a visual analogue scale. RESULTS: The percentage of patients who complained of cough was significantly higher with lisinopril than with losartan or hydrochlorothiazide. The mean visual analogue scale scores for patients treated with lisinopril demonstrated that these patients coughed more frequently than those who received losartan or hydrochlorothiazide. CONCLUSION: The incidence of cough related to the type 1 Ang II receptor antagonist losartan is significantly lower than that observed with lisinopril, and similar to that observed with hydrochlorothiazide in patients with a rechallenged ACE inhibitor cough. Type 1 Ang II receptor antagonists represent a potential new treatment for hypertensive patients in whom ACE inhibitors are indicated, but who develop a cough with these agents.

Adult↗
PubMed1993

Toxicokinetics of pentachloroanisole in F344 rats and B6C3F1 mice.

1. Toxicokinetics of pentachloroanisole (PCA) were studied in F344 rat and B6C3F1 mouse of both sexes by gavage at doses of 10, 20 and 40 mg/kg and by i.v. at 10 mg/kg. 2. PCA was rapidly demethylated to pentachlorophenol (PCP) in both rat and mouse and the resulting PCP plasma concentrations were much higher than that of parent PCA due to the much smaller apparent volume of distribution of PCP. 3. Peak plasma concentrations of PCA and PCP increased with dose in both rat and mouse. 4. Bioavailability of PCA was low in both rat and mouse and was sex independent. 5. The high plasma concentrations and relatively long biological half-life of PCP in both species after both i.v. and oral dosing with PCA indicate possible bioaccumulation of PCP upon multiple oral administrations of PCA.

Animals↗
PubMed1992

Identifiable semen donors--attitudes of donors and recipient couples.

Fifty-three couples embarking on donor insemination (DI) replied to an anonymous questionnaire asking what they wanted to know about the donor should they become pregnant. Fifty-one percent were definitely and 32% probably going to tell a child of its donor origins. Items most frequently listed for themselves and on behalf of a child were--interests/sports (57%), physical attributes (41%), occupation (37%) and family background (26%). Forty-two percent of the women and 28% of the men thought the child should have access to the identity of the donor eventually. Thirty-eight donors were surveyed by a questionnaire; 68% were agreeable to their identity being available to a donor insemination child when the child reached maturity. When the category of identifiable donor was created, 20 of 36 (56%) new donors and donors still donating chose this option.

Adult↗
PubMed1992

Efficacy of ticarcillin-clavulanic acid for treatment of experimental Staphylococcus aureus endocarditis in rats.

The efficacy of ticarcillin-clavulanic acid was compared with the efficacies of standard antistaphylococcal agents (flucloxacillin, oxacillin, nafcillin, and vancomycin) and ticarcillin in an experimental model of Staphylococcus aureus endocarditis. Therapy was either initiated soon (8 h) after infection, when numbers of bacteria in aortic valve vegetations were relatively low (approximately 6 to 8 log10 CFU/g), or delayed until 24 h after infection, when the vegetations usually contained greater than 9 log10 CFU/g. Doses of the antibiotic were selected to produce peak concentrations in rat serum similar to those achievable in humans after administration of parenteral therapeutic doses. Ticarcillin-clavulanic acid was more effective overall than ticarcillin alone against endocarditis caused by beta-lactamase-producing strains of S. aureus, illustrating the beta-lactamase-inhibitory activity of clavulanic acid in vivo. Ticarcillin-clavulanic acid was as effective as the standard antistaphylococcal beta-lactam agents flucloxacillin, oxacillin, and nafcillin in these infections, whereas vancomycin was generally less active. These results illustrate the clinical potential of ticarcillin-clavulanic acid in the prophylaxis or therapy of severe staphylococcal infections.

Animals↗
PubMed1992

NTP technical report on the toxicity studies of Castor Oil (CAS No. 8001-79-4) in F344/N Rats and B6C3F1 Mice (Dosed Feed Studies).

Castor oil is a natural oil derived from the seeds of the castor bean, Ricinus communis. It is comprised largely of triglycerides with a high ricinolin content. Toxicity studies with castor oil were performed by incorporating the material at concentrations as high as 10% in diets given to F344/N rats and B6C3F1 mice of both sexes for 13 weeks. Genetic toxicity studies also were performed and were negative for mutation induction in Salmonella typhimurium, for induction of sister chromatid exchanges or chromosomal aberrations in Chinese hamster ovary cells, and for induction of micronuclei in the peripheral blood erythrocytes of mice evaluated at the end of the 13-week studies. Exposure to castor oil at dietary concentrations as high as 10% in 13-week studies did not affect survival or body weight gains of rats or mice (10 per sex and dose). There were no biologically significant effects noted in hematologic analyses in rats. Mild increases in total bile acids and in serum alkaline phosphatase were noted at various times during the studies in rats receiving the higher dietary concentrations of castor oil. Liver weights were increased in male rats receiving the 10% dietary concentration and in male and female mice receiving diets containing 5% or 10% castor oil. However, there were no histopathologic lesions associated with these liver changes, nor were there any compound-related morphologic changes in any organ in rats or mice. No significant changes were noted in a screening for male reproductive endpoints, including sperm count and motility, and no changes were observed in the length of estrous cycles of rats or mice given diets containing castor oil. Thus, no significant adverse effects of castor oil administration were noted in these studies. Synonyms: Ricinus Oil, oil of Palma Christi, tangantangan oil, phorboyl, Neoloid.

Journal Article↗
PubMed1991

Efficacy of amoxycillin/clavulanic acid in experimental Staphylococcus aureus endocarditis in the rat.

The efficacy of amoxycillin/clavulanic acid was compared with that of flucloxacillin, vancomycin and amoxycillin in an experimental model of Staphylococcus aureus endocarditis. Doses of the antibiotics were selected to produce peak concentrations in rat serum similar to those achievable in man after administration of parenteral therapeutic doses. Amoxycillin clavulanic acid was more effective than amoxycillin alone against endocarditis caused by beta-lactamase producing strains of Staph. aureus, illustrating the beta-lactamase inhibitory activity of clavulanic acid in vivo. Amoxycillin/clavulanic acid was as effective as flucloxacillin in these infections whereas vancomycin was generally less active. These results illustrate the clinical potential of amoxycillin/clavulanic acid in the prophylaxis, or in the therapy of severe staphylococcal infections.

Amoxicillin↗
PubMed1990

Self-monitored smoking motives.

The motives for smoking in 73 low, medium, and high rate smokers were surveyed and were evaluated the validity of the Reasons for Smoking scale (RFS) by correlating RFS scores with self-monitored reasons for smoking. Combined sample correlations were significant for 5 of the 6 RFS reasons. However, all correlations were modest, the number of correlations varied with smoking rate, and the RFS was not a valid measure of pleasurable relaxation, the reason most frequently reported during self-monitoring. The unexpected finding that pleasurable relaxation, not reduction of negative affect, was the most frequently endorsed reason conflicts with previous surveys, almost all of which sampled older smokers. Smoking behavior of younger smokers may differ from older smokers in ways important to the study of smoking motivation. These differences may explain why experimental studies with undergraduates generally find no relationship between smoking and negative affect while studies with older subjects do.

Adolescent↗
PubMed1990

Sequential technetium-99m sulfur colloid/indium-111 white blood cell imaging in macroglobulinemia of Waldenstrom.

Technetium-99m sulfur colloid (SC) and indium-111 labeled leukocyte (In-111 WBC) scintigraphy was performed on a 77-year-old female patient to rule out a left periprosthetic infection. Anterior Tc-99m SC and In-111 WBC images of the pelvis and femurs revealed no abnormal deposition of radiotracer about the Austin-Moore prosthesis. Absent radiotracer uptake, however, was demonstrated within the left hemipelvis. A left iliac bone marrow aspirate and biopsy revealed a lymphoplasmacytic infiltrate consistent with Waldenstrom's macroglobulinemia.

Aged↗
PubMed1985

Comparative chronic toxicities and carcinogenic potentials of 2-ethylhexyl-containing compounds in rats and mice.

Four compounds containing a 2-ethylhexyl moiety [di(2-ethylhexyl)phthalate (DEHP), di(2-ethylhexyl)adipate (DEHA), tris(2-ethylhexyl)phosphate (TEHP), and 2-ethylhexyl sulfate (EHS)] were tested for carcinogenic and other chronic and subchronic toxic effects in 90-day and 2-year studies in male and female Fischer 344 rats and B6C3F1 mice. The low generalized toxic potencies of the test chemicals allowed relatively high doses of all of these compounds to be administered. Despite differences in chemical structure, all four chemicals were related to increased occurrences of hepatocellular neoplasms, principally carcinomas, in female mice. DEHA and DEHP also induced hepatocellular neoplasms in male mice, while DEHP caused hepatocellular neoplasms in both male and female rats. No other neoplasms were considered to be unequivocally related to compound administration in these studies. There was a positive correlation between the magnitude of the hepatocarcinogenic response in female mice and the probability of a hepatocarcinogenic response in male mice and in male and female rats, suggesting quantitative differences in the carcinogenic potentials of these agents. These results suggest that compounds containing a 2-ethylhexyl moiety (and 2-ethylhexanol, by implication) may possess some carcinogenic potential, especially for the rodent liver. No other organ-specific toxic effects common to two or more test chemicals were observed in these studies.

Adipates↗
PubMed1982

On office design.

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Dental Offices↗
PubMed1979

Isolation of a single polypeptide leucyl-tRNA synthetase from bakers' yeast.

A single polypeptide of leucyl-tRNA synthetase (LRS) has been purified from budding bakers' yeast by a modification of the procedure published earlier. On denaturing polyacrylamide gel electrophoresis LRS was one band corresponding to molecular weight of 120,000 +/- 5,000 daltons. Variable amounts of LRS with a similar molecular weight but which dissociated into equal subunits of 58,000 were also isolated. The affinities (KM) for substrates for this form of the enzyme were similar to those previously reported for the dimeric form of the enzyme.

Amino Acyl-tRNA Synthetases↗