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Biomedical subjects

H White

Publications and source records attributed to H White.

At least 127 records · Page 7Linked to original sources
PubMed1989

Carboxylic acid reductase: a new tungsten enzyme catalyses the reduction of non-activated carboxylic acids to aldehydes.

An enzyme which we call carboxylic acid reductase (aldehyde dehydrogenase) seems to be the first which is able to reduce non-activated carboxylic acids to aldehydes at the expense of reduced viologens. There is no further reduction of the aldehydes to the corresponding alcohols. In the presence of oxidized viologens aldehydes can be dehydrogenated to carboxylic acids roughly 20 times faster than the latter are reduced. The specific enzyme activity in crude extracts is about 100 times increased if 10 microM tungstate and a sulphur source in addition to sulphate is given to the growth medium of Clostridium thermoaceticum. Carboxylic acid reductase seems to be present in two forms. One has an apparent molecular mass of about 240 kDa and is bound to red-Sepharose, whereas, the other, a form of an apparent molecular mass of about 60 kDa, is not bound. SDS gel electrophoresis shows a higher complexity. The very labile enzyme has been enriched by a factor of about 145 by binding to octyl-Sepharose and further chromatographic separation by red-Sepharose and FPLC using Mono-Q and phenyl-Superose columns. After cell growth in the presence of [185W]tungstate, radioactivity coincides with the two forms of enzyme activity during all purification steps. This is also the case when the enzyme is electrophoretically separated on polyacrylamide slab gels.

Aldehyde Oxidoreductases↗
PubMed1989

Omental transposition in the treatment of locally advanced and recurrent breast cancer.

An analysis was carried out of 43 patients treated by omental transposition for locoregional problems associated with breast cancer. Indications for surgery included advanced primary tumour (five), locally recurrent tumour (32), radiation induced sarcoma (two), and radionecrosis (four). Tumours were typically extensive (mean diameter 7.2 cm) and skin ulceration affected 30 patients. Other treatment modalities had been exhausted. Surgical excision followed by reconstruction using transposed omentum resulted in worthwhile local control and symptom relief in 31 patients (median duration 22 months). Chest wall disease rapidly recurred peripheral to the omental graft in 12 patients. On multiple regression analysis, duration of local control was significantly related to tumour diameter, ulceration, and earlier radioresistance (hazard ratios 15.8, 3.8 and 14.8 respectively). Survival (median 21, range from 1.5 to 122 months) correlated with tumour size, previous chemotherapy, and early re-recurrence (hazard ratios 7.2, 3.0 and 4.3). Omental transfer is a reliable method of restoring epithelial cover after radical surgery and is particularly useful after previous irradiation injury. In advanced and recurrent breast cancer, an aggressive surgical approach significantly improved the quality of life of most patients, but careful case selection is required to avoid inappropriate surgery for irremediable tumours.

Adult↗
PubMed1989

Hemispheric asymmetries in interpreting forms vs colors in ambiguous patterns.

Prior to receiving briefly lateralized presentations of ambiguous visual patterns (Rorschach inkblots), 28 normal right-handed males heard two words, each describing a different interpretation of the pattern, e.g., one word might describe an interpretation based on attending to shapes or forms (form choices) and the other might describe an interpretation based on attending to chromatic color (e.g., color choices). Color choices were more frequent than form choices on left-hemisphere (LH) presentations of the patterns, and form choices were more frequent than color choices on right-hemisphere (RH) presentations. These results were interpreted as consistent with the theory that the LH's favored mental representation is semantic (i.e., frequent choices of concepts associated with names of colors in the patterns) and the RH's favored representation is imaginal (i.e., frequent choices of concepts associated with difficult-to-label forms in the patterns).

Adult↗
PubMed1989

Short-term exposure to nitrogen dioxide enhances susceptibility to murine respiratory mycoplasmosis and decreases intrapulmonary killing of Mycoplasma pulmonis.

In C57BL/6N and C3H/HeN mice known to be free of all murine pathogens and matched for age, sex, microbiologic, and environmental factors, exposure to NO2 for 4 h prior to exposure to infectious aerosols of Mycoplasma pulmonis resulted in potentiation of murine respiratory mycoplasmosis (MRM). In the C57BL/6N mice, NO2 increased the incidence of death, incidence of gross lung lesions, and incidence of microscopic lung lesions, but did not increase the incidence of infection in the lungs. Nitrogen dioxide affected the C3H/HeN mice (a strain known to be more susceptible than the C57BL/6N strain to MRM) similarly, with the exception that the incidence of death and microscopic lesions were not affected in this strain at the concentrations of M. pulmonis used. Exposure to the oxidant also increased the severity of microscopic lesions and the numbers of Mycoplasma organisms in the lungs of both mouse strains. Thus, NO2 appeared to affect host lung defense mechanisms responsible for limiting the extent of infection. The NO2 exposure level required to produce potentiation varied with the genetic background of the host, the number of Mycoplasma organisms administered, and the end point measured. In further experiments in C57BL/6N mice, exposure to 5 or 10 ppm of NO2 for 4 h prior to infection with aerosolized, radiolabeled M. pulmonis reduced clearance of these organisms from the lungs over a 72-h time period. Nitrogen dioxide exposure did not change the rate of physical removal of Mycoplasma organisms from the lung. Reduced clearance was due to impaired intrapulmonary killing of Mycoplasma organisms in NO2-exposed mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1989

Isolation of bovine herpesvirus-3 from African buffaloes (Syncerus caffer).

Eleven virus isolations were made from the blood of 45 free living healthy African buffaloes by long term cocultivation of their leucocytes with bovine thymus or spleen cells. The isolates were indistinguishable from each other or from herpesviruses isolated from a severely ill buffalo calf and from a dead buffalo. These viruses possessed the characteristics of the bovine herpesvirus-3 (BHV-3) group and were indistinguishable by serology and restriction endonuclease analysis from the BHV-3 type strains Movar 33/63 and DN599. There was a 93.6 per cent prevalence of indirect immunofluorescent antibody to BHV-3 in the sera of 94 buffaloes in the sample population. No clinical signs or viraemia were detected in five cattle inoculated with 10(8.7) log10 TCID50 of the isolate from the sick buffalo calf. Two of three cattle hyperimmunised with this virus resisted challenge with malignant catarrhal fever herpesvirus, which proved fatal for the other immunised animal and for three control cattle.

Animals↗
PubMed1988

Fibrils from brains of cows with new cattle disease contain scrapie-associated protein.

During the past two years, more than 1,000 cases of a neurological disorder of cattle, bovine spongiform encephalopathy (BSE), have been confirmed from farms throughout Great Britain. The neurological signs and brain pathology of BSE resemble those produced in other species by the pathogens of scrapie and related disorders. The discovery of fibrils similar to scrapie-associated fibrils in detergent extracts o BSE-affected brain supported the clinical and pathological diagnosis of the disease, but has been controversial. Scrapie-associated fibrils are found in brain extracts of all species affected by scrapie and diseases caused by related pathogens. They are pathological aggregates of a neuronal membrane protein termed PrP and a protease-resistant form of PrP is a molecular marker of scrapie-associated fibrils. In this report, we show the major protein of BSE fibrils is the bovine homologue of PrP as judged by its size, protease resistance, immunoreactivity, lectin binding and partial N-terminal protein sequence. This confirms that BSE is a scrapie-like disease.

Amino Acid Sequence↗
PubMed1988

Serological comparisons of antigenically related herpesviruses in cattle, red deer and goats.

Serological comparisons were made using related herpesviruses from cattle (bovid herpesvirus 1), red deer (herpesvirus of cervidae 1) and goats (bovid herpesvirus 6) by virus neutralization and enzyme-linked immunosorbent assays. The test samples comprised field sera from British cattle, red deer and goats and sera from experimentally infected or immunized animals. Both the cervine and caprine viruses appeared to be more closely related to bovid herpesvirus 1 than they were to each other. Cattle sera reacted most strongly with the bovine virus and deer sera with the cervine virus. Antibodies to the caprine virus were not detected in the samples from British goats.

Animals↗
PubMed1988

Colonic metaplasia with colonic-type polyps on an ileostomy stoma in polyposis coli. Report of a case.

A unique case is reported in which chronic physical and chemical irritation of an ileostomy stoma (after proctocolectomy for polyposis coli) was associated with colonic metaplasia and formation of colonic-type tubular adenomas on the external surface of the ileostomy. The remainder of the terminal ileum and the upper gastrointestinal tract were normal, with no evidence of Gardner's syndrome. This case demonstrates that even metaplastic colonic epithelium is susceptible to the formation of adenomas in polyposis coli patients.

Adenomatous Polyposis Coli↗