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Biomedical subjects

L Westbrook

Publications and source records attributed to L Westbrook.

34 records · Page 2Linked to original sources
PubMed1985

Comparison of the use of reserpine versus alpha-methyldopa for second step treatment of hypertension in the elderly.

A retrospective chart analysis was conducted on all new elderly hypertensive patients referred to a community hypertension clinic who were being treated with either reserpine or alpha-methyldopa plus a diuretic. There were no significant differences between the two groups on entry in age, gender, co-morbid diagnoses, or systolic or diastolic blood pressure. There were no significant differences between the two groups in terms of side effects over three years, but the proportion of persons having compliance problems was significantly lower in the reserpine group. Mean diastolic pressures were significantly lower after one, two, and three years, and systolic pressures were lower after one and two years in the reserpine group. Reserpine is at least as effective as alpha-methyldopa in treating hypertension in the elderly and is associated with fewer problems in compliance.

Aged↗
PubMed1983

Comparison of the efficacy of vidarabine, its carbocyclic analog (cyclaradine), and cyclaradine-5'-methoxyacetate in the treatment of herpes simplex virus type 1 encephalitis in mice.

The relative therapeutic effects of vidarabine (9-beta-D-arabinofuranosyladenine), cyclaradine (the adenosine deaminase-resistant carbocyclic analog of vidarabine), and cyclaradine-5'-methoxyacetate in the parenteral treatment of systemic herpes simplex virus type 1 infections in Swiss mice were determined. Among control mice inoculated intraperitoneally with virus, a mortality rate of 95% was observed. The intraperitoneal administration of nontoxic doses of vidarabine (125 to 250 mg/kg per day) or cyclaradine (113 to 450 mg/kg per day), by daily injections for 7 days beginning 4 h after virus inoculation, reduced mortality to 0 to 10%. Among control animals inoculated intracerebrally with 32 50% lethal doses of virus, 100% mortality was observed, with a mean survival time of 4.6 days. Treatment with either drug at equimolar dose levels ranging from ca. 32 to 750 mg/kg per day produced significant (P less than 0.0005), dose-dependent increases in the mean survival time of animals dying of herpesvirus encephalitis. Mice inoculated intracerebrally with 10 50% lethal doses of virus exhibited 97% mortality and a mean survival time of 5.5 to 6.4 days. Treatment with vidarabine, cyclaradine, or cyclaradine-5'-methoxyacetate significantly increased the mean survival time of dying animals and, at doses ranging from 250 to 750 mg/kg per day, produced significant increases in survival. The three drugs displayed equivalent antiviral efficacy in vivo. Drug toxicity (measured by weight loss) was not detected in mice treated with cyclaradine or cyclaradine-5'-methoxyacetate at 750 mg/kg per day, whereas severe toxicity (weight loss of greater than or equal to 3 g) was observed in mice treated with vidarabine at an equivalent dose level. Thus, cyclaradine or its 5'-methoxyacetic acid ester may possess some advantage over vidarabine in the treatment of severe herpesvirus infections and should therefore be considered for clinical trials in humans.

Animals↗
PubMed1981

Evaluation of carbodine, the carbocyclic analog of cytidine, and related carbocyclic analogs of pyrimidine nucleosides for antiviral activity against human influenza Type A viruses.

Carbodine, the carbocyclic analog of cytidine, was found to possess significant antiviral activity against influenza virus types A0/PR-8/34 and A2/Aichi/2/68 (Hong Kong) in vitro. The compound selectively inhibited PR-8 influenza virus-induced cytopathogenic effects in Madin-Darby canine kidney and inhibited Hong Kong influenza virus replication in primary rhesus monkey kidney cell cultures. The 50% minimum inhibitory concentration for inhibition of human influenza type A viruses by carbodine was approximately 2.6 microgram/ml (i.e., in the range of antiviral potency of ribavirin, but less potent than amantadine hydrochloride in concomitant assays). The fact that carbodine is metabolized to carbodine triphosphate in mammalian cells makes interference with the viral ribonucleic acid-dependent ribonucleic acid polymerase reaction a likely possibility for its principal mode of action. The carbocyclic analogs of uridine (the deamination product of carbodine), 2'-deoxycytidine, 3'-deoxycytidine, N,N-dimethylcytidine, N-methylcytidine, and some related carbocyclic analogs of pyrimidine nucleosides were inactive against PR-8 influenza virus in vitro. The combination of carbodine plus tetrahydrouridine was no more effective in vitro than carbodine alone, thus indirectly indicating that deamination of carbodine probably did not occur to a significant degree during the cell culture experiments. Although reproducibly active in vitro, carbodine did not exhibit any efficacy against lethal influenza virus infections in mice when administered by either the intraperitoneal or intranasal routes up to dose-limiting toxic levels.

Animals↗
PubMed1971

Quantitative studies on fabrics as disseminators of viruses. V. Effect of laundering on poliovirus-contaminated fabrics.

The effects of laundering with both anionic and nonionic detergents in cold, warm, and hot water on poliovirus-contaminated cotton sheeting, cotton terry cloth, washable wool shirting, wool blanketing, dull nylon jersey, and dacron/cotton shirting were determined. The fabrics were exposed to virus by aerosolization and direct contact (pipette) in separate studies. Although the results varied with each factor used in the study, virus titers on all the fabrics were generally reduced considerably by the laundering process. When the fabrics were dried for 20 hr after laundering, an additional decline in virus titers was seen, often to below detectable levels. The type of detergent used made little difference in effect on virus titer reduction, but the hot wash water markedly reduced the detectable virus. Fabric type was not a major factor in the majority of the experiments, although virus tended to be eliminated more readily from the nylon jersey, and in warm water the virus persisted longer on wool blanketing material laundered in anionic detergent. Sterile fabrics of each type laundered with similar fabrics which contained virus often became contaminated by the virus during the laundering process. Virus titers ranging from undetectable to 10(3.9) cell culture 50% infectious doses/ml were obtained from samples of the rinse water after warm- and cold-water laundering.

Animals↗
PubMed1971

Potentially infectious agents associated with shearling bedpads: effect of laundering with detergent-disinfectant combinations on Staphylococcus aureus and Pseudomonas aeruginosa.

Glutaraldehyde-tanned woolskins which are used as bedpads to prevent decubitus ulcers were contaminated with Staphylococcus aureus (ATCC 6538) and Pseudomonas aeruginosa (ATCC 15442). Two methods of exposure, direct contact and aerosol, were used in separate experiments. Attempts were made to decrease the bacterial population placed on the woolskins by laundering them in a quaternary ammonium disinfectant, a phenolic disinfectant, or alkalinized glutaraldehyde, in combination with an anionic or nonionic detergent. The effect of a commercial detergent-sanitizer was also studied. Bacterial populations were significantly reduced in all experiments, but only laundering in glutaraldehyde in combination with either detergent resulted in maximum removal of bacteria. Viable bacteria were usually not detected in the rinse water (<1 viable organism/5 ml of rinse water).

Aldehydes↗
PubMed1970

Potentially infectious agents associated with shearling bedpads. I. Effect of laundering with detergent-disinfectant combinations on polio and vaccinia viruses.

Glutaraldehyde-tanned woolskin pads which are used for the prevention of decubitus ulcers in bed patients were experimentally contaminated with polio or vaccinia viruses. Two methods of exposure, direct contact and aerosol, were used in separate experiments. Attempts were made to remove or inactivate these virus contaminants by laundering the woolskins in a quaternary ammonium disinfectant, a phenolic disinfectant, or alkalinized glutaraldehyde, in combination with an anionic detergent or a nonionic detergent. The effect of a commercial detergent-sanitizer was also studied. The virus titers were significantly reduced in all experiments, but only laundering in glutaraldehyde in combination with either detergent lowered the vaccinia virus titers to below detectable limits. High concentrations of glutaraldehyde altered the texture of the wool and leather apparently by precipitating a component of the detergent onto the fibers. In all the poliovirus experiments, the virus was still detectable on either or both the wool and the leather of the pads after laundering. The rinse water from each experiment was tested for the presence of virus. No vaccinia virus was recovered, but poliovirus was demonstrated in titers up to 10(3) cell culture 50% infectious doses.

Animals↗
PubMed1970

Quantitative studies on fabrics as disseminators of viruses. IV. Virus transmission by dry contact of fabrics.

Cotton and woolen fabrics and fabrics of synthetic fibers were exposed by direct contact (pipette) and by aerosolization to poliovirus and to vaccinia virus in separate experiments, allowed to dry for 16 hr at 25 C in 35% relative humidity, and randomly tumbled with sterile swatches of the same fabrics for 30 min. By use of a HEp-2 cell assay system, up to 10(3.5) CCID(50) of poliovirus per ml and 10(4.4) CCID(50) of vaccinia virus per ml were recovered from the originally sterile fabrics as early as 1 to 10 min after contact. Maximum transfer of both viruses was achieved with wool blanket material, although high titers of vaccinia virus were recovered from all fabrics tested. Poliovirus placed on the fabrics in an aerosol tended to be transferred to the sterile fabrics at a greater rate than when it was placed on the fabrics by direct contact. The method of exposure had essentially no effect on the rate of transfer of vaccinia virus.

Aerosols↗
PubMed1969

Factors affecting the persistence of Staphylococcus aureus on fabrics.

The persistence of Staphylococcus aureus (Smith) on wool blanket, wool gabardine, cotton sheeting, cotton knit jersey, cotton terry cloth, and cotton wash-and-wear fabrics was studied. The fabrics were exposed to bacterial populations by three methods: direct contact, aerosol, and a lyophilized mixture of bacteria and dust having a high content of textile fibers. The contaminated fabrics were held in 35 or 78% relative humidities at 25 C. In general, the persistence time of S. aureus populations on fabrics held in 35% relative humidity was substantially longer when the fabrics were contaminated by exposure to aerosolized cultures or to dust containing bacteria than when contaminated by direct contact. In a 78% relative humidity, bacterial populations on the fabrics persisted for substantially shorter periods of time regardless of the mode of contamination or fabric type. Cotton wash-and-wear fabric (treated with a modified triazone resin) was the material on which populations of S. aureus persisted for the shortest time. This organism retained its virulence for Swiss mice after being recovered from wool gabardine swatches held 4 weeks in 35% relative humidity and 6 weeks in 78% relative humidity.

Animals↗
PubMed1969

Procedure for the evaluation of the virucidal effectiveness of an ethylene oxide gas sterilizer.

A quantitative, reproducible method was developed for the evaluation of the virucidal activity of test gases. Using this method, we determined the virucidal effectiveness of a Steri-Vac ethylene oxide gas sterilizer. Wool gabardine material was exposed to high concentrations of herpes simplex, vaccinia, parainfluenza, or polio viruses and was processed through the sterilizer. Two time-temperature cycles of the machine, 29 C for 180 min and 60 C for 48 min, were used in separate experiments. The viruses were exposed to the gas when freshly pipetted onto the fabric or when pipetted on the material and allowed to dry 16 to 24 hr. In two experiments carried out under each condition, the virus titers were reduced by the sterilization process to less than detectable limits. These titer reductions were for the herpes virus >/= 2.7 to 5.0 log, for vaccinia virus >/= 4.0 to 6.1 log, for parainfluenza virus >/= 1.8 to 4.9 log, and for poliovirus >/= 4.9 to 7.7 log. The observed reductions in virus titers were the same whether the virus-contaminated fabrics were sealed in polyethylene packages or held in open petri dishes during exposure to ethylene oxide.

Antisepsis↗
PubMed1969

Persistence of Salmonella typhimurium on fabrics.

The persistence of Salmonella typhimurium (V-31) on wool blanket, wool gabardine, cotton sheeting, cotton knit jersey, cotton terry cloth, and cotton wash-and-wear fabrics was studied. Three methods of exposure were employed to contaminate the fabrics: direct contact, aerosol, and a lyophilized mixture of bacteria and dust having a high content of textile fibers. After contamination, the fabrics were held in 35 or 78% relative humidity at 25 C. The persistence time of S. typhimurium on fabrics held in 35% relative humidity was substantially longer when the fabrics were contaminated by direct contact or by exposure to dust containing bacteria than when contaminated by exposure to aerosolized cultures. Viable bacterial populations persisted for 24 weeks at relatively high population densities on swatches of wool gabardine, cotton sheeting, cotton knit jersey, and cotton terry cloth exposed by direct contact and held in a humidity of 35%. In 78% humidity, bacterial populations persisted on the fabrics for relatively shorter periods of time regardless of the mode of contamination or fabric type. This organism retained its virulence for Swiss mice after being recovered from wool gabardine swatches held 8 weeks in humidities of 35 or 78% and from cotton terry cloth swatches held 6 weeks in the same humidities.

Aerosols↗