Biomedical subjects

J B Wright

Publications and source records attributed to J B Wright.

At least 37 records · Page 2Linked to original sources

PubMed1991

Decreased biocide susceptibility of adherent Legionella pneumophila.

In a study of the in vitro effectiveness of biocides against Legionella pneumophila, some aspects of the cooling tower environment were replicated in the laboratory, paying particular attention to water hardness and pH. Pieces of Douglas fir and polyvinyl chloride were colonized in a recirculating system and the comparative efficacy of two biocides (Bronopol and Kathon) against the sessile and planktonic populations was examined. While the biocides were relatively effective against the planktonic L. pneumophila population over a short period of time (minimum 9-12 h), substantially longer periods of time (maximum greater than 48 h) were required to reduce the number of cultivable bacteria to below detectable levels in the adherent population. The results indicate that failure to monitor the sessile population of L. pneumophila in laboratory studies of biocides may result in the use of incorrect dosages and/or contact times in field trials with apparently reduced in situ efficacy.

Anti-Bacterial Agents↗

PubMed1989

Atypical legionellosis: isolation of Legionella pneumophila serogroup 1 from a patient with aspiration pneumonia.

It has been suspected that the number of Legionella pneumophila infections is substantially higher than commonly reported, due to subclinical infections. We report a patient where the diagnosis of a legionella infection was made only because of a large-scale surveillance programme for legionellosis. The case demonstrates the possibility of legionellas being involved in lung disease though not necessarily causing overt legionellosis.

Adult↗

PubMed1989

Legionella pneumophila grows adherent to surfaces in vitro and in situ.

Legionella pneumophila continues to play a role in both community- and nosocomially-acquired pneumonia. We investigated the ability of L pneumophila to adhere to various types of materials such as those found in the hospital air-cooling and portable water distribution systems. Through the use of a unique sampling apparatus, we were able to regularly acquire planktonic and sessile samples and determine the numbers of bacteria present in both populations, in vitro and in situ. Portions of these apparatuses could be aseptically removed for examination by scanning electron microscopy, or for the determination of the number of viable adherent L pneumophila. The number of bacteria present in each sample was determined by direct plate count, with presumptive L pneumophila colonies being positively identified by direct fluorescent antibody staining techniques. The results demonstrated that not only are legionellae capable of colonizing various metallic and nonmetallic surfaces but that they are preferentially found on surfaces. Surface-adherent bacteria may play a profound role as a reservoir of these potential pathogens in aquatic environments. Furthermore, these results suggest that any comprehensive legionella monitoring program must include not only water samples but also an examination of the adherent populations.

Air Conditioning↗

PubMed1986

Are patients attracted to family physicians by the AAFP's "Competitive Edge" marketing materials?

A prospective study was conducted at a large military family practice clinic to assess the effectiveness of the AAFP's "Competitive Edge" marketing package. Four hundred and sixty-six Army families were randomly assigned to three study groups when they first arrived at Fort Benning, Georgia. One of these groups received two marketing brochures from the "Competitive Edge." The three groups were then followed for two years. There was no significant difference in the rate of enrollment for care in the Family Practice Clinic among the three groups (power = .95). Demographic data suggested that older soldiers who had higher military rank, smaller families, and those who had received care from a family physician in the past were more likely to enroll in family practice. The study demonstrated that the attitudes and knowledge of enrollees and non-enrollees toward the clinical skills of a family physician were similar. A study like this is relatively easy to perform and can be very useful market research for an individual practice.

Adult↗

PubMed1985

Antibiotic resistance of Pseudomonas aeruginosa colonizing a urinary catheter in vitro.

A modified Robbins Device was used to establish coherent biofilms of Pseudomonas aeruginosa on the surface of catheter material in an artificial urine milieu and the ability of an antibiotic to penetrate the biofilm and kill the enclosed bacteria was assessed. The Pseudomonas aeruginosa strain used had been isolated from a patient with urinary tract infection. Although planktonic (floating) cells of the Pseudomonas aeruginosa strain were inhibited by less than 1 mg/l of tobramycin and killed by 50 mg/l, contact with 1,000 mg/l of tobramycin for 12 h failed to kill all the sessile (adherent) bacteria in the biofilms on the surface of the catheter material. Surviving sessile bacteria recovered directly from the exposure to 1,000 mg/l of tobramycin were inhibited by 0.4 mg/l of this agent when tested as dispersed planktonic cells by standard MIC methods. It is suggested that growth within thick adherent biofilms confers upon cells of Pseudomonas aeruginosa a large measure of resistance to aminoglycosides and other antibiotics that may help to explain the frequent failure of antibiotic chemotherapy in catheter-associated urinary tract infections.

Anti-Bacterial Agents↗

PubMed1985

Tobramycin resistance of Pseudomonas aeruginosa cells growing as a biofilm on urinary catheter material.

When disks of urinary catheter material were exposed to the flow of artificial urine containing cells of Pseudomonas aeruginosa, a thick adherent biofilm, composed of these bacteria and of their exopolysaccharide products, developed on the latex surface within 8 h. After this colonization, sterile artificial urine containing 1,000 micrograms of tobramycin per ml was flowed past this established biofilm, and a significant proportion of the bacterial cells within the biofilm were found to be still viable after 12 h of exposure to this very high concentration of aminoglycoside antibiotic. Planktonic (floating) cells taken from the test system just before the exposure of the biofilm to the antibiotic were completely killed by 50 micrograms of tobramycin per ml. The MIC of tobramycin for cells taken from the seeding cultures before colonization of the catheter material, and for surviving cells recovered directly from the tobramycin-treated biofilm, was found to be 0.4 micrograms/ml when dispersed cells were assayed by standard methods. These data indicate that growth within thick adherent biofilms confers a measure of tobramycin resistance on cells of P. aeruginosa.

Equipment Contamination↗

PubMed1983

Lymphedema treated with a linear pump: pediatric case report.

This first report on the use of the Wright linear pump and its successful application in the treatment of a child with Park-Weber syndrome indicates that sequenced linear pumping is efficacious when previously tried single cell intermittent compression fails. Programmable intermittent pressure in the management of lymphedema in children offers a preferable choice.

Angiomatosis↗

PubMed1979

The effect of lodoxamide ethyl [diethyl N,N'-(2-chloro-5-cyano-m-phenylene)dioxamate] on in vivo anaphylactic reactions.

Orally administered iodoxamide ethyl (U-42,718) inhibited anaphylactic reactions in a dose-related manner in the following test animals: (1) in the rat PCA reaction, excellent activity (75% inhibition at 0.1 mg/kg) was seen with a duration of activity of 30 min, (2) In the ascaris-sensitive primate (45% inhibition at 1.0 mg/kg) in lung parameters related to increased resistance and decreased compliance which persisted for up to 3 h, and (3) 50 mg/kg protected guinea pigs, sensitized to egg albumin, from lung function changes. Activity in these animal systems indicates that this orally active drug may hold promise in clinical asthma.

Aerosols↗

PubMed1978

N,N'-(Phenylene)dioxamic acids and their esters as antiallergy agents.

A series of dialkyl N,N'-(m-phenylene)dioxamates was synthesized by treatment of the requisite m-phenylenediamines with an alkyloxalyl chloride in the presence of triethylamine. Hydrolysis with sodium hydroxide solution gave the corresponding N,N'-(m-phenylene)dioxamic acids. Several N,N'-(p-phenylene)dioxamic acids were synthesized also in the same manner starting with the requisite p-phenylenediamines. These compounds were tested in the rat passive cutaneous anaphylaxis (PCA) assay. When tested iv, activity was found in the N,N'-(m-phenylene) dioxamic acids up to 2500 times that shown by disodium cromoglycate [50% inhibition at 0.001 mg/kg for N,N'-(2-chloro-5-cyano-m-phenylene)dioxamic acid (compound 61)]. Oral activity was seen in this series of compounds with duration of activity up to 120 min. Oral activity was detected in diethyl N,N'-(2-chloro-5-cyano-m-phenylene)dioxamate (compound 38) at levels of drug as low as 0.1 mg/kg.

Administration, Oral↗

PubMed1978

Structure-activity correlations for a series of antiallergy agents. Oxanilic, quinaldic, and benzopyran-2-carboxylic acids.

Ab initio Hartree-Fock SCF calculations with the molecular fragment technique have been performed on several drugs which exhibit activity in the rat passive cutaneous anaphylaxis (PCA) assay. Representative molecules of the following types were included in the series: oxanilic acids, 1,4-dihydro-4-oxoquinaldic acids, and 4-oxo-4H-1-benzopyran-2-carboxylic acids. A quantitative relationship has been established between the observed biological activity and an electronic index obtained from the calculations. The correlation is rationalized in terms of charge-transfer stabilization of the drug-receptor complex.

Amino Acids↗

PubMed1978

Inhibition of allergic reactions by cromoglycate and by a new anti-allergy drug U-42,585E. I. Activity in rats.

A new inhibitor of IgE-mediated allergic reactions has been studied in rats. This new inhibitor is chemically different from cromoglycate and shows qualitative and quantitative advantages over it. It is 2,500 times more active in rats than disodium cromoglycate and shows oral activity. This new inhibitor possesses no bronchodilator or end-organ antagonism activity and does not raise intracellular cAMP levels but as cromoglycate acts by inhibition of mediator release. Multiple high (25 mg/kg) doses in rats lead to tachyphylaxis. This effect is reversed both by decreasing the first dose and increasing the time between doses. Over a 5- to 10-fold concentration range, this inhibitor in mast cells can be stimulatory or inhibitory to 45Ca++ flux into cells. This ability to inhibit ionophore-induced 45Ca++ flux correlates well with inhibition of histamine release.

Administration, Oral↗

PubMed1978

Inhibition of allergic reactions by cromoglycate and by a new antiallergy drug U-42,585E. II. Activity in primates against aerosolized Ascaris suum antigen.

Immediate type hypersensitivity to Ascaris antigen in Rhesus reactor monkeys was used to assess the pharmacologic profile of cromolyn Na (DSCG) and a new inhibitor of IgE-mediated lung function changes (U-42,585E). Two parameters used to measure lung function, respiratory rate increase and tidal volume decrease, were significantly altered in a dose-related fashion by U-42,585E when the latter was administered either by the intravenous, intrabronchial, or the oral route. Oral activity of U-42,585E was demonstrated with doses as low as 5 mg/kg in Ascaris reactor primates.

Administration, Intranasal↗

PubMed1977

(2-Carboxy-1,4-dihydro-4-oxoquinolyl)oxamic acids and (2-carboxy-1,4-dihydro-4-oxobenzo[h]quinolyl)oxamic acids as antiallergy agents.

A group of (2-carboxy-1,4-dihydro-4-oxoquinolyl)oxamic acids (5) containing the oxamic acid group in the 5,6, or 7 positions were synthesized and investigated for antiasthma activity as indicated by the passive cutaneous anaphylaxis (PCA) reaction in rats. Also synthesized and investigated were two (2-carbosy-1,4-dihydro-4-oxobenzo[h]-quinolyl)oxamic acids (9 and 10). Several of the compounds synthesized (viz. 5e, 5f, and 10) showed activity in the PCA test approximately 25 times that shown by disodium cromoglycate (1), as measured by the ID50 doses.

Animals↗

PubMed1977

Quinoline derivatives as antiallergy agents. 2. Fused-ring quinaldic acids.

A series of compounds containing two or more 4-oxo-1,4-dihydropyridine-2-carboxylic acid units fused to a central aromatic nucleus was synthesized and tested in the rat passive cutaneous anaphylaxis (PCA) assay for potential antiallergy activity. Most of the compounds of this series showed significant activity in the PCA assay. Three of these compounds. 11d, 13f, and 21, were more than 250 times as active as the standard drug, cromolyn sodium. The synthesis and biological activity are discussed.

Animals↗

PubMed1974