Biomedical subjects
R H Coleman
Publications and source records attributed to R H Coleman.
Properties of beta-lactamase from Pseudomonas syringae.
Pseudomonas syringae isolate BR2R produces tabtoxin, a beta-lactam-containing antibiotic, and the causative agent of wildfire disease of green bean (Phaseolus vulgaris). beta-Lactamase production has been suggested as the mechanism that protects P. syringae from tabtoxin. We sought to determine whether the organism produces beta-lactamase and whether the enzyme plays a role in protection from this antibiotic. P. syringae and mutants defective in tabtoxin production and resistance produce beta-lactamase. Three distinct beta-lactamases with molecular weights of 41,000 were identified. The isoelectric points of the proteins were 6.1, 6.8, and 9.2. The enzymes preferentially hydrolyze cephalosporin. This investigation demonstrates that the organism produces multiple beta-lactamases and describes characteristics of the proteins.
A computerized expert system for handling the output of the Technicon H1 haematology analyser.
A computer-based expert system is described which handles the output of the Technicon H1 in the haematology laboratory of a large teaching hospital. Using patient request data, analyser results, error and morphology flags, the expert system decides; whether to validate the main indices plus differential; whether a blood film is required for manual review; and which abnormal results require phoning to the requesting doctor. The results of this computer-assisted analysis are sent to a printer adjacent to the analyser. The print-out details any further action required of the operator before release of results to the main hospital computer, and serves as a log of all samples run on that analyser. Benefits of the expert system include greatly simplified interpretation of the large array of analyser flags, and consistency in sample handling for all operators over all shifts.
Cloning and expression of the tabtoxin biosynthetic region from Pseudomonas syringae.
Pseudomonas syringae BR2, a causal agent of bean wildfire, was subjected to Tn5 mutagenesis in an effort to isolate mutants unable to produce the beta-lactam antibiotic tabtoxin. Three of the tabtoxin-minus (Tox-) mutants generated appeared to have physically linked Tn5 insertions and retained their resistance to the active toxin form, tabtoxnine-beta-lactam (T beta L). The wild-type DNA corresponding to the mutated region was cloned and found to restore the Tn5 mutants to toxin production. The use of cloned DNA from the region as hybridization probes revealed that the region is highly conserved among tabtoxin-producing pathovars of P. syringae and that the region deletes at a relatively high frequency (10(-3)/CFU) in BR2. The Tox- deletion mutants also lost resistance to tabtoxinine-beta-lactam. A cosmid designated pRTBL823 restored toxin production and resistance to BR2 deletion mutants. This cosmid also converted the tabtoxin-naive P. syringae epiphyte Cit7 to toxin production and resistance, indicating that pRTBL823 contains a complete set of biosynthetic and resistance genes. Tox- derivatives of BR2 did not produce disease symptoms on bean. Clones that restored toxin production to both insertion and deletion mutants also restored the ability to cause disease. However, tabtoxin-producing Cit7 derivatives remained nonpathogenic on bean and tobacco, suggesting that tabtoxin production alone is not sufficient to cause disease.
Rotating shift work schedules that disrupt sleep are improved by applying circadian principles.
Workers on rotating shifts dislike those aspects of their work schedules that violate circadian sleep-wake cycle physiology. Work schedule satisfaction, subjective health estimates, personnel turnover, and worker productivity improve when schedules are introduced that are designed to incorporate circadian principles.
Regulation of formation of aerial mycelia and spores of Streptomyces viridochromogenes.
Growth of Streptomyces viridochromogenes on a solid glycerol-NH4NO3 salts medium was accompanied by the formation of aerial mycelia and spores. Adding 0.5% or more casein hydrolysate to the medium stimulated growth while completely repressing the formation of aerial mycelia and spores. This repression was temporary, as evidenced by the fact that transfer of the organisms to media not containing casein hydrolysate resulted in the appearance of aerial mycelia and spores. The effects of individual amino acids were tested. Glycine retarded growth and repressed formation of both aerial mycelia and spores. L-Aspartic acid, L-glutamic acid, and L-histidine stimulated or had little effect on growth and repressed formation of spores but not aerial mycelia. Repression by casein hydrolysate could not be attributed to the carbon/nitrogen ratio or the pH of the medium. Adding 1.25 to 2.5 mM adenine to the medium caused a reversal of the casein hydrolysate repression of aerial mycelium formation but did not reverse repression of sporulation. Dimethyladenine and 8-azaguanine had an effect similar to that of adenine, but a variety of other purine or pyrimidine derivatives had no effect on casein hydrolysate repression. The repression of aerial mycelium and spore formation by casein hydrolysate occurred only in media containing 15 mM or more phosphate. Aerial mycelia and spores were formed in media containing casein hydrolysate and 3 mM or less phosphate.
Complementary and alternative medicine use among children in the Washington, DC area.
OBJECTIVE: To determine the prevalence and reasons for complementary and alternative medicine (CAM) use among children in primary pediatric care practice in the Washington, DC area. DESIGN: Cross-sectional survey of parents at 4 Children's National Medical Center Pediatric Research Network (PRN) practices from July 1998 through November 1998. Survey information included demographics, child health problems, satisfaction with health care, and CAM use over the past year. RESULTS: Parents completed 348 surveys. Forty percent (138) of parents were CAM users themselves, whereas 21% (72) had treated their child with CAM over the past year. Factors positively associated with child CAM use included parents' use of CAM (P <.0001); greater parent age (P =.0005); greater child age (P =.001); and complaints of frequent respiratory illnesses, asthma, headaches, and nosebleeds. Ethnicity and parental education were not associated with child CAM use. Over 50% of pediatric CAM users reported specific vitamin supplementation, whereas 25% used other nutritional supplements or elimination diets, and over 40% used herbal therapies. Thirty-two percent of CAM users had visited a CAM practitioner; 81% of pediatric CAM users would have liked to discuss it with their pediatrician, but only 36% did so. CONCLUSION: Treatment of children with CAM is common and is frequently undertaken by parents without the knowledge or advice of their pediatrician.