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Biomedical subjects

H Peck

Publications and source records attributed to H Peck.

At least 19 recordsLinked to original sources
PubMed1992

Investigation of an outbreak of methicillin-resistant Staphylococcus aureus in patients with skin disease using DNA restriction patterns.

OBJECTIVE: To investigate an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) among patients using chromosomal typing of the isolates. DESIGN: Comparison of epidemiological and clinical data to endonuclease restriction fragmentation analysis (RFA) of the MRSA isolates associated with an outbreak. Total DNA from the MRSA isolates was restricted with HINDIII and HAEIII for typing. SETTING: Tertiary care academic medical center. METHODS: An epidemiological investigation of an outbreak of MRSA among patients in private rooms was evaluated by routine infection control methods. The MRSA isolates from blood cultures of 7 patients and the nares of a nurse were collected during the outbreak. MRSA isolates from 23 patients not associated with the outbreak also were collected. The total DNA of the MRSA isolates were restricted with HINDIII and HAEIII and electrophoresed on 0.6% agarose gels. RESULTS: MRSA from 4 of the 7 bacteremic patients and the nurse on the outbreak unit had the same endonuclease restriction pattern. The patients were linked in that they were compromised by severe psoriasis or skin ulcers, were on the unit during the same period, and had oatmeal baths in a common bathtub. Of 50 staff members screened, the nurse was the only person detected as colonized by the strain. The other 3 patients on the unit as well as the 23 patients in other locations not associated with the outbreak had MRSA isolates with different RFA patterns. The use of the bathtub was discontinued and further transmission of MRSA was stopped. CONCLUSIONS: A comparison of the relatedness of MRSA by RFA demonstrated the uniqueness of the epidemiologically linked isolates and the utility of the RFA technique in the performance of routine infection control investigations.

Bacterial Typing Techniques↗
PubMed1988

Introduction of genes for leucine biosynthesis from Clostridium pasteurianum into C. acetobutylicum by cointegrate conjugal transfer.

A Clostridium pasteurianum gene bank was constructed in Escherichia coli, using plasmid pAT153, and several chromosomal fragments found which complemented both leuB and leuC mutations in auxotrophic E. coli K12 strains. No fragments capable of complementing leuA or leuD mutations were identified. Conjugal transfer of the leuB/leuC genes from Bacillus subtilis into two different Leu- C. acetobutylicum auxotrophic strains was elicited by their incorporation into a large plasmid cointegrate composed of the conjugal plasmid pAM beta 1 and a specially constructed gram-positive, replication-deficient plasmid, pMTL21 EC. Inheritance of the cointegrate plasmid restored one of the auxotrophic C. acetobutylicum strains to prototrophy. The second strain remained Leu-.

3-Isopropylmalate Dehydrogenase↗
PubMed1979

The occurrence of gamma-glutamylphenylalanine in the urine of newborn phenylketonurics.

The urine of untreated phenylketonurics in the first weeks of life contains gamma-glutamylphenylalanine (0.07--0.69 mmol/g creatinine, 12 samples) visible on the normal 2-dimensional electrophoreto-chromatogram. This compound is less prominent or absent when urine from older untreated phenylketonurics is examined and is not seen in normal urine.

Creatinine↗
PubMed1979

Frequency of tooth extraction in orthodontic treatment.

Orthodontic extraction frequency describes the percentage of an orthodontic patient population experiencing extractions of one or more permanent teeth, excluding third molars. It is a useful statistical measure of the many variables associated with the extraction-nonextraction decision. For a study sample of 537 North American white orthodontic patients, the frequency of tooth extraction was determined as 42.1 percent. This is compared with a range of 6.5 percent to 83.5 percent reported in the world dental literature. Factors responsible for the enormous differences in orthodontic extraction frequency are explored. The study of extraction frequency offers a simple, valuable aid for the clinician to understand better the nature of his patient population, his treatment methods, and his rationalizations.

Adolescent↗
PubMed1979

Acute toxicity of methyl fluorosulfonate (Magic Methyl).

Methyl fluorosulfonate (Magic Methyl), an active methylating agent used by research chemists, was studied for acute oral toxicity, acute inhalation toxicity, ocular irritation, and dermal irritation. This compound is very hazardous and may have been responsible for at least one human death. The results of these studies confirmed that Magic Methyl is markedly toxic by all routes studied and particularly by the inhalation route since the LC50 value for rats was found to be between 5 and 6 ppm.

Administration, Oral↗
PubMed1979

Radiographic features of Legionnaires' disease.

Serial chest radiographs of 35 patients with confirmed Legionnaires' disease were evaluated. A unilateral, unilobar alveolar infiltrate was, in general, the initial radiographic finding. Progression to consolidation or to new areas of involvement was typical. Every lobe was involved, but lower lobe involvement was most common. Pleural effusion was often present. Cavitation was not seen. Radiographic progression for several days following institution of therapy, and despite clinical response, was noted. In patients who survived, radiographic improvement of abnormalities was usually apparent within two weeks of therapy. Aradiographic spectrum exists and, although many features are typical, no single feature is pathognomonic.

Aged↗
PubMed1976

Mutagenic evaluation of ronidazole.

Ronidazole was evaluated for mutagenic potential using in vitro microbial tests and in vivo studies in mice. The microbial test used the histidine requiring mutants of Salmonella typhimurium with and without a rat liver microsomal activation system (Ames test). The studies in mice included the dominant lethal test, micronucleus test and cytogenetic assays. Ronidazole was given orally in doses of 50, 100 and 200 mg/kg/day in the in vivo studies. In the dominant lethal test, groups of male mice were treated for five consecutive days before being mated with untreated females. In the micronucleus test, the mice were administered the compound for 2 or 5 consecutive days; they were killed 6 h after the last dose and bone marrow was examined for the presence of micronuclei in developing erythrocytes. In the cytogenetic assays, bone marrow cells in metaphase were examined for chromosome aberrations, 6, 24 and 48 h after mice were treated acutely with the test compound. In addition, similar examinations of chromosomes were made on mice given five consecutive dosages of ronidazole and killed 6 h after the last dose. The results of the various in vivo studies did not suggest that ronidazole would be mutagenic for the mammal. Ronidazole at concentrations of 10 and 50 mug/plate was found to increase the number of back mutations of missense mutants in the in vitro bacterial test. This finding confirms the results of Voogd et al. [19]. Incorporation of the microsomal activation system had no effect on the mutagenic capability of the test compound. In conclusion, although ronidazole was shown to be mutagenic in in vitro bacterial systems, the in vivo systems did not suggest that the compound would be mutagenic for the mammal.

Animals↗
PubMed1975

Othodontic aspects of dental anthropology.

Variation in the size, shape, number, arrangement, and wear pattern of the teeth of man has long been an area of great interest to physical anthropologists. In this paper some of the remarkable variations to be found in the human dentition are identified and translated in orthodontic terms. Teeth are by nature imperfect structures, often just as disfigured individually as the malocclusions they form collectively. It is important that the orthodontist cultivates an anthropologist's eye for tooth variations. With this sensitivity he shall surely enlarge his understanding of the limitations of orthodontic therapy and shall appreciate the valuable role of tooth altering procedures in achieving treatment success.

Adolescent↗