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Biomedical subjects

P Mitchell

Publications and source records attributed to P Mitchell.

At least 487 records · Page 27Linked to original sources
PubMed1984

Sodium butyrate-induced alteration of growth properties and glycogen levels in cultured human colon carcinoma cells.

The effect of sodium butyrate on three cultured human colon carcinoma cell lines was studied. Exposure to butyrate caused morphological changes and resulted in the alteration of several growth properties. Doubling times of treated cells were increased five-fold and saturation densities and cloning efficiencies were decreased, compared to untreated cells. Histochemical studies using the periodic acid-Schiff reaction in conjunction with diastase digestion showed that butyrate induced increased glycogen levels in all three cell lines. This increase was confirmed by biochemical techniques. These effects of butyrate were reversed when treated cells were subsequently grown in the absence of butyrate. These changes are consistent with findings from several laboratories that butyrate can induce phenotypic changes in cultured tumour cells.

Butyrates↗
PubMed1983

Evaluation of the effectiveness of a low sodium diet in the treatment of mild to moderate hypertension.

28 patients who had a sustained diastolic blood pressure of 95 to 104 mm Hg and who had no treatment for it for at least 13 months before the trial, but who were otherwise unselected, took part in a randomised controlled trial in which the effect of a restricted sodium diet was compared with that of a general health package. The general health package did not include any specific hypotensive procedures. Changes in blood pressure were measured at predetermined intervals over the course of a year. Within each group both systolic and diastolic blood pressure fell to a highly significant extent after a year, but there was no significant difference between the groups. It would thus seem that the antihypertensive effect of a restricted sodium diet may be related to the increased consultation and monitoring activity of such intervention rather than to the dietary manipulation itself.

Clinical Trials as Topic↗
PubMed1983

Alternative hypotheses of proton ejection in cytochrome oxidase vesicles. Transmembrane proton pumping or redox-linked deprotonation of phospholipid-cytochrome c complex(es).

A review of published experimental and interpretative knowledge concerning proton ejection associated with cytochrome c oxidation by artificial phospholipid vesicles inlaid with cytochrome c oxidase indicates that the detailed characteristics of the redox-linked proton ejection cannot be simply explained by proton pumping. We propose an alternative hypothesis according to which proton ejection is due to the redox-linked deprotonation of a complex involving phospholipid and cytochrome c at the surface of the vesicles. The postulates upon which this hypothesis depends are explicitly outlined, and some methods of testing the hypothesis are suggested.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗
PubMed1983

Self-reported dark red bleeding as a marker comparable with occult blood testing in screening for large bowel neoplasms.

The study was designed to determine the prevalence of large bowel symptoms in an adult working population and to assess their value in screening for large bowel neoplasms. A symptom questionnaire was sent to workers in two large organizations and the results were compared with faecal occult blood testing in the same individuals using Haemoccult (Eaton Laboratories). Completed symptom questionnaires and Haemoccult test kits were returned by 916 out of a total of 1805 employees over the age of 40 (compliance 50.7 per cent). Twenty-eight (3.1 per cent) were Haemoccult positive and 114 (12.4 per cent) had one or more symptoms. All positives (129 persons) were examined by flexible sigmoidoscopy and barium enema. No cancer was found but 7 patients with adenomas greater than 10 mm diameter were discovered. Each of the 7 patients reported at least one symptom (dark red bleeding in 4, bright red bleeding in 2 and diarrhoea in 1) and 6 were Haemoccult positive. There was no individual with a Haemoccult positive adenoma without symptoms. Predictive values for adenomas over 10 mm for Haemoccult positive tests (21 per cent), self-reported dark bleeding (16 per cent) and diarrhoea (17 per cent), were significantly higher than for other symptoms. The predictive value rose significantly to 46 per cent for Haemoccult-positive patients who in addition had at least one symptom (P less than 0.05) and to 57 per cent for Haemoccult positive with dark bleeding. These combinations of Haemoccult- and symptom-positive results increased the specificity of 97.6 per cent for Haemoccult alone to values over 99 per cent without reducing sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1982

Contrast sensitivity in diabetics with retinopathy and cataract.

Contrast sensitivity responses were determined in diabetic subjects with retinopathy, macular disease and cataract. The test proved reliable in discriminating between different degrees of cataract and between diabetics with no retinopathy, mild background retinopathy and early maculopathy. Background retinopathy was shown to produce a loss of contrast sensitivity particularly at the low and medium frequencies. These thresholds increased with macular involvement. Mild cataract was correlated with loss at the low and medium spatial frequencies, whilst moderate cataract suppressed sensitivity to all frequencies. Results are compared to colour discrimination in each patient.

Adolescent↗
PubMed1981

Lymphocytotoxic and microbial antibodies in Crohn's disease and matched controls.

Patients with Crohn's disease and age, sex and seasonally matched healthy controls were studied for cold lymphocytotoxic and a variety of microbial antibodies. Lymphocytotoxic antibody titers were increased significantly in the Crohn's patients compared to controls, but did not correlate with any of the microbial titers. Antibodies to a Pseudomonas-like bacterium and Bacteroides vulgatus were also increased in the patients, but titers to Chlamydia trachomatis, rotavirus and Norwalk virus were not elevated above control values. Analysis of microbial antibody within the patient and control groups revealed a significant (P = .001) correlation between antibodies to the Pseudomonas-like bacterium and Bacteroides vulgatus. The elevated titers to the Pseudomonas-like organisms and B. vulgatus are of potential importance, but their significance is not known at this time. There is no evidence of an increased incidence of infection with C. trachomatis, rotavirus or Norwalk virus in Crohn's disease.

Adult↗
PubMed1981

Induction by butyrate of differentiated properties in cloned murine rhabdomyosarcoma cells.

A cell line derived from the murine rhabdomyosarcoma BW10139 (Dexter, Cancer Res. 37: 3136, 1977) was subcloned and examined with respect to growth and myogenic characteristics in the presence and absence of 1 mM butyrate. Without butyrate, these cells behave as typical transformed cells: they grow rapidly and chaotically, do not form multinucleated muscle fibers and have little or no creatine kinase activity. In the presence of 1 mM sodium butyrate or butyric acid, growth slows, cells become arranged in whorl patterns, and creatine kinase activities increase to levels comparable to those found in normal chick myoblasts immediately prior to cell fusion. The increase in creatine kinase activity is detectable within 2 h exposure to butyrate, reaches a maximum by 24 h, and the elevated level can be maintained for at least six weeks. The induction is reversible upon sequential addition, deletion, and readdition of butyrate to the culture medium. Isoenzyme analyses demonstrated that only the BB form of creatine kinase is induced; MM creatine kinase was not detected. Although formation of multinucleated cells increases after exposure to butyrate, no typical myotubes form. The results suggest that this rhabdomyosarcoma cell line can, under appropriate conditions, re-express some properties characteristic of skeletal muscle, but not the complete muscle phenotype.

Animals↗
PubMed1981

Intimacy and emotional illness in the general population.

Ninety married couples in the general population received a structured interview to assess their level of intimacy. The couples also completed self-report questionnaires to assess non-psychotic emotional illness and marital adjustment. High levels of intimacy were associated with martial adjustment. Low ratings of marital intimacy were significantly associated with non-psychotic emotional illness and psychiatric help-seeking. These findings are discussed in relationship to recent studies which explore the role of lack of marital intimacy as a vulnerability factor in the development of non-psychotic emotional illness. Implications for treatment of non-psychotic emotional illness in married individuals is briefly discussed.

Adult↗