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Biomedical subjects

D H Williams

Publications and source records attributed to D H Williams.

At least 163 records · Page 9Linked to original sources
PubMed1983

Cardiovascular and metabolic responses of trained and untrained middle-aged men to a graded treadmill walking test.

A treadmill walking test was developed in order to provide a suitable method of assessing the fitness levels of sedentary middle-aged men (mean age, 44.3 yrs) at submaximal intensity. The incremental stages of the test enabled subjects to terminate the workload whenever undue discomfort was experienced. The test procedure was used in a preliminary experiment to compare the cardiovascular and metabolic responses of trained and untrained middle-aged men to exercise. Heart rate responses to the test were significantly higher (p less than 0.01) in the untrained, compared with the trained, men as were the post-exercise blood lactic acid concentrations (p less than 0.01), Respiratory Exchange Ratios (p less than 0.01), Ventilatory Equivalents (p less than 0.05) and Rate of Perceived Exertion (p less than 0.01). However, there were no differences in the oxygen cost of walking between the two groups.

Adult↗
PubMed1983

Immunobiology of primary intracranial tumors. Part 7: Active immunization of patients with anaplastic human glioma cells: a pilot study.

Twenty patients with malignant gliomas were selected for active immunization within 4 weeks following surgery. Each patient had a Karnofsky Functional Rating equal to or greater than 70, a peripheral blood lymphocyte count equal to or greater than 1000 cells/cu mm, skin test responses to one or more of four recall antigens, peripheral blood T-cells equal to or greater than half that of control, and was not receiving steroid therapy at the time of entry into the study. Each patient received subcutaneous inoculations with one of two human glioma tissue culture cell lines (D-54MG or U-251MG) monthly, with 500 micrograms of bacillus Calmette-Guérin cell wall (BCG-CW) being included with the first inoculation. Each patient also received levamisole, 2.5 mg/kg 3 days per week every other week. Radiotherapy and chemotherapy with BCNU were begun after the first month of immunization. Follow-up evaluations included computerized tomography brain scans, neurological examinations, Karnofsky Functional Ratings, and studies of general immune competence. No evidence of allergic encephalomyelitis was noted clinically, nor was any gross or microscopic evidence of such pathology obtained upon autopsy of three of these patients. Serial studies of general immune competence showed no alterations from those previously described with non-immunized patients. Patients who were inoculated with the U-251MG cell line have had a longer survival time compared to those inoculated with the D-54MG cell line (p less than 0.0590) or compared to 58 historical cases of glioma patients treated with levamisole, radiation therapy, and chemotherapy alone (p less than 0.02).

Adult↗
PubMed1982

Identification of the NH2-terminal blocking group of calcineurin B as myristic acid.

The NH2-terminal blocking group of the Ca2+-binding B-subunit of calcineurin (protein phosphatase-2B) has been identified as myristic acid by fast atom bombardment mass spectrometry and gas chromatography. The sequence, myristyl-Gly-Asn-Glu-Ala-, is very similar to that of the catalytic subunit of cyclic AMP-dependent protein kinase, the only other protein known to contain this fatty acid. This finding, and the elution of all myristyl peptides at 57% acetonitrile on reverse phase HPLC, may facilitate the identification of other proteins with this blocking group.

Amino Acids↗
PubMed1982

Fast-atom-bombardment mass spectrometry. A new technique for the determination of molecular weights and amino acid sequences of peptides.

A detailed study of the mass spectra of peptides produced by the new technique of fast-atom bombardment is reported. Molecular weights of unmodified peptides containing up to 21 amino acids have been determined. In favourable cases, the molecular-weight determination may be made on as little as 0.1 nmol of sample. Positive-ion and negative-ion spectra are obtained with equal facility. With sample sizes in the range 2-50nmol, sequence information can be obtained in many cases. The technique represents an important contribution to structural studies on peptides, since (i) blocked peptides may be studied, (ii) no prior formation of chemical derivatives is necessary (except for distinction between lysine and glutamine), (iii) sensitivity is good, (iv) large peptides, and, in some cases, mixtures of peptides, can be studied, and (v) the technique is easy to operate, with ions being produced over a long period (5-30 min).

Amino Acid Sequence↗
PubMed1982

Configuration assignments of the amino acid residues and the presence of N-methyldehydroalanine in toxins from the blue-green alga, Microcystis aeruginosa.

The configuration assignment of the alpha-carbon atom of amino acid residues in four toxin variants from Microcystis aeruginosa have been made by stereospecific enzymic transformations. The relative conformation assignment of the beta-carbon atom of beta-CH3-aspartic acid could be made by comparison of the electrophoretic mobility with literature values reported for the authentic compound. The presence of an N-methyldehydroalanine residue, which, due to elimination of methylamine under hydrolytic conditions, previously escaped detection by conventional means, has been confirmed by identification of N-methylalanine in the hydrolysate after reduction of toxin with sodium borohydride.

Alanine↗
PubMed1982

Structure and conformation of fourteen antibiotics of the quinoxaline group determined by 1H NMR.

Nuclear magnetic resonance has been employed to characterize fourteen new antibiotics belonging to the quinoxaline group, produced by feeding aromatic acids to Streptomyces echinatus. Twelve of the antibiotics are the expected substituted quinomycins and adopt conformations very similar to that of echinomycin. This is discussed in relation to their different DNA-binding characteristics. The other two antibiotics are triostins, supporting the proposal that triostins serve as biosynthetic precursors of the quinomycins.

Anti-Bacterial Agents↗
PubMed1981

Mass spectrometric sequence studies of a superoxide dismutase from Bacillus stearothermophilus.

A partial sequence of the manganese-containing superoxide dismutase from Bacillus stearothermophilus has been determined by mass spectrometry. A new fragmentation reaction at N-terminal proline is described and an 'in-chain' fragmentation, also occurring at proline, has been observed. There is some evidence that the latter cleavage may also occur at other residues. Some differences from the classically determined sequence are reported, and the validity of these observations is discussed.

Amino Acid Sequence↗
PubMed1980

Assessment of social adjustment in chronic ambulatory schizophrenics.

Fifty-six chronic schizophrenic outpatients and their significant others were interviewed separately and given the Social Adjustment Scale II. Intraclass correlations revealed a statistically significant level of agreement between the patients' and the significant others' reports of social adjustment. The mean scores for different areas of social adjustment showed considerable variation, and there were interesting differences between the raters' and significant others' judgments of the social adjustment of the patient.

Employment↗
PubMed1980

Deinstitutionalization and social policy: historical perspectives and present dilemmas.

The influence of social and economic forces on the placement and treatment of the chronically mentally ill is traced historically. This review suggests that minorities and the poor, who have in the past suffered the worst institutional care, will be most at risk in the community during the present era of cutbacks in social services. Deinstitutionalization, in making claims on resources that the larger community is reluctant to grant, seen as jeopardizing needed incremental reforms.

Deinstitutionalization↗
PubMed1979

Treatment of secondary depression in schizophrenia. A double-blind, placebo-controlled trial of amitriptyline added to perphenazine.

The combination of antidepressants and neuroleptics has been widely recommended and commonly used clinically for the schizophrenic patient who becomes depressed. However, the value of the combination for these patients has not been clearly demonstrated. This report presents results of a double-blind, randomized, placebo-controlled clinical trial designed to evaluate the combination of perphenazine and amitriptyline hydrochloride with that of perphenazine alone in the treatment of 35 ambulatory chronic schizophrenic patients in whom depressive symptoms developed. Results showed that the addition of amitriptyline to perphenazine, when compared with perphenazine alone, was more effective in reducing symptoms of depression after four months of treatment, but less effective in reducing thought disorder. The study concludes that the value of adding an antidepressant to the usual neuroleptic in the treatment of secondary depression in schizophrenia should be reviewed.

Adolescent↗
PubMed1979

Time course of increased collateral arterial and venous endothelial cell turnover after renal artery stenosis in the rat.

We induced left renal artery stenosis in rats and studied collateral arterial formation by angiography, histology, and radioautography with tritiated thymidine. Endothelial cell turnover was estimated by radioautography with tritiated thymidine in the periureteric blood supply of 10 normal and 38 collateral-forming kidneys 1 to 100 days after stenosis. Periureteric arterial endothelial cell labeling showed a highly significant (P less than 0.005) increase, apparent within 1 day and gradually falling as the vessels grew, until a baseline was reached in 35 days. A smaller but statistically significant increase in the labeling index also was found in endothelial cells of the renal vein during the first week (P less than 0.01), and had a similar time course. A marked increase in epithelial cell labeling in the ureters draining the stenotic kidneys also was evident (P less than 0.005). Thus, collateral vessel development is characterized by active DNA synthesis in the cellular elements which is maximal during the first week. A humoral factor is implicated in the vascular response by the parallel proliferation of venous and uretic cellular elements that are unlikely to experience the biophysical forces, such as increased blood flow or tangential wall force, which might stimulate proliferation in ther arterial vessels.

Animals↗