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Biomedical subjects

W F Marshall

Publications and source records attributed to W F Marshall.

42 records · Page 3Linked to original sources
PubMed1989

Xanthomonas maltophilia: an emerging nosocomial pathogen.

Xanthomonas maltophilia is a potentially pathogenic organism with a broad clinical spectrum. Nosocomial colonization and infection are the most common manifestations. The incidence of clinical isolation of X. maltophilia is on the rise, possibly in part because of the selective pressure from the new antimicrobial agents to which it is resistant. The organism is usually resistant to commonly used antimicrobial agents, including most cephalosporins, aztreonam, antipseudomonal penicillins, imipenem, and the quinolones.

Bacterial Infections↗
PubMed1989

Atropine therapy and paralytic ileus in an infant.

Signs of intestinal obstruction developed in a 2-month-old infant with trisomy 21 during atropine therapy. Radiographic evaluation strongly suggested Hirschsprung's disease, but rectal biopsy yielded normal histologic results. Following cessation of atropine use, the symptoms resolved completely. This case report demonstrates the association between atropine therapy and intestinal ileus. Caution is advised when using topical atropine therapy in children, especially those with Down's syndrome.

Administration, Topical↗
PubMedDate not supplied

Mutagenicity of diesel exhaust particle extracts: influence of driving cycle and environmental temperature.

General Motors and Volkswagen diesel passenger cars (1980 and 1981 model year) were operated on a climate controlled chassis dynomometer and the particulate portion of the exhaust was collected on high volume filters. Dichloromethane extracts of the exhaust particles (soot) collected while the cars were operated under simulated highway, urban and congested urban driving cycles were assayed for mutagenicity in Salmonella strains TA-98 and TA-100. Driving pattern did not significantly influence the mutagenic potency of the exhaust particle extracts or estimates of the amount of mutagenicity emitted from the exhaust despite large differences in particle emission rates and extractable fraction of the particles. Mutagenicity of extracts of exhaust particles collected while the vehicles were operated at test chamber temperatures of 25, 50, 75 and 100 degrees F were also very similar. The results suggest that driving pattern and environmental temperature do not significantly alter the emission of genotoxic combustion products from the exhaust.

Animals↗
PubMedDate not supplied

Mutagenicity of diesel exhaust particle extracts: influence of fuel composition in two diesel engines.

The influence of diesel fuel composition on mutagenicity of exhaust particle associated organic compounds has been investigated using nine fuels varying in aromatic content and distillation properties. The tests were conducted with Oldsmobile Delta-88 and Peugot 504 diesel cars operated according to the EPA Federal Test Procedure. The particulate exhaust from each test was collected on a filter, extracted in dichloromethane and the resulting extract evaluated for mutagenicity in Salmonella strain TA-100. Mutagenicity of extracts of particles collected from the Oldsmobile were highest in the higher aromatic content fuels (greater than 30%) but similar for intermediate (20%) and low (13%) aromatic content fuels. No influence of aromaticity on mutagenicity was observed in samples collected from the Peugeot under the same conditions. Thus, fuel aromatic content may enhance the production of mutagenic combustion products at higher concentrations, but may be dependent upon engine type. A good correlation was observed between mutagenicity of the particle extracts and the initial boiling point of the fuel (r = 0.89). Gas chromatography/mass spectrometric analysis of the aromatic fraction of the fuels showed that the fuel producing the most mutagenic combustion products was highest in phenanthrene type compounds.

Animals↗
PubMedDate not supplied

Pretransplantation seronegative Epstein-Barr virus status is the primary risk factor for posttransplantation lymphoproliferative disorder in adult heart, lung, and other solid organ transplantations.

BACKGROUND: The relative importance and interrelationship of risk factors for posttransplantation lymphoproliferative disorder are poorly understood. METHODS: The prospective pretransplantation serologic testing for Epstein-Barr virus of all nonrenal solid organ transplant recipients at our institution made it possible to assess the relative risk for posttransplantation lymphoproliferative disorder in seropositive and seronegative recipients. RESULTS: Fourteen cases of lymphoproliferative disorder were identified in the first 389 consecutive transplant recipients (288 liver, 44 heart, 20 lung, 37 kidney-pancreas) undergoing transplantation from 1985 to 1992 (mean follow-up 33 months). The incidence rates of lymphoproliferative disorder (per 100 person-years) during the first 2 years after transplantation (a period in which all cases occurred) were 1.4 for liver, 2.0 for heart, 6.2 for lung, and 5.2 for kidney-pancreas transplant recipients and were significantly different between liver and lung (p = 0.005) and liver and kidney-pancreas (p = 0.002) groups. Of 367 seropositive patients, lymphoproliferative disorder developed in only three. The incidence rate ratios between seronegative and seropositive recipients were as follows: 76 ([95% confidence interval; 46, 144], p = 0.0000) for any form of lymphoproliferative disorder and 145 ([60, 347], p = 0.0000) for fatal or brain forms. The incidence rate of lymphoproliferative disorder was significantly higher for seronegative recipients who required antilymphocyte antibody therapy for rejection than for those who received none. CONCLUSIONS: The high intrinsic risk for lymphoproliferative disorder in the Epstein-Barr virus seronegative patient, which is amplified by higher levels of immunosuppression, may, in some instances, preclude transplantation.

Acyclovir↗