Search PubMed⌕ Search

Biomedical subjects

C Stevens

Publications and source records attributed to C Stevens.

At least 163 records · Page 9Linked to original sources
PubMed1984

Arginine aminopeptidase activity of phytopathogenic spiroplasmas.

The arginine aminopeptidase activity of arginine-utilizing phytopathogenic spiroplasmas was investigated with arginine beta-naphthylamide substrate using the fluorometric method. Hydrolysis of this substrate was demonstrated with broth cultures, washed concentrated whole cells, and cell-free extracts of corn stunt spiroplasma (CSS) and Spiroplasma citri. Growing CSS and S. citri in the presence of 47 mM arginine resulted in a reduction in aminopeptidase activity, indicating that synthesis of the enzyme might be subject to control by catabolic repression. Results of these experiments suggest a possible biochemical basis for pathogenicity of phytopathogenic spiroplasmas in vivo.

Aminopeptidases↗
PubMed1983

Relationship between a pulmonary function test (FEV1) and the ADAPT quality-of-life scale.

In a previous study the Additive Daily Activities Profile Test (ADAPT) correlated .83 with maximum oxygen consumption among pulmonary rehabilitation patients. The present study expanded the pulmonary population base and compared the ADAPT scores of 41 patients at two independent centers with a more readily available parameter, the forced expiratory volume in the first second of forced exhalation (FEV1). The relationships between the two major ADAPT subscales and FEV1 were significant but lower in magnitude than that found with maximum oxygen consumption. The ADAPT continues to be sensitive to physical impairment and in translating the effect of impairment upon daily physical activity.

Activities of Daily Living↗
PubMed1982

L-dopa treatment of Parkinson's disease: a ten-year follow up study.

A ten-year follow-up study of parkinsonian patients treated with L-dopa is presented. Originally 130 patients entered the study, and previous reports were presented in 1971 and 1973. This report concerns the 47 remaining patients now available for examination. The effectiveness of L-dopa diminished over the ten-year period, so that the disability states of these patients are now similar to those prevailing just before the study began ten years ago. Despite the decline, the interim improvement and the patients' relatively asymptomatic existence for part of the time confirm the effectiveness of L-dopa therapy in the treatment of Parkinson's disease.

Aged↗
PubMed1980

Transfusion-transmitted viruses study: experimental evidence for two non-A, non-B, hepatitis agents.

Plasma, serum, and a concentrate of factor VIII, implicated in human cases of non-A, non-B (NANB) hepatitis, were inoculated into four chimpanzees. All four animals demonstrated significant elevations of alanine aminotransferase levels within five weeks. After recovery from these NANB hepatitis episodes, the chimpanzees were cross-challenged with different inocula. A second episode of NANB hepatitis occurred after challenge in three animals. Reproducibility of the results was established by reversing the sequence of inoculation in two of the animals. A known infectious concentrate of factor VIII failed to induce hepatitis in a previously infected chimpanzee although the animal remained susceptible to a third inoculum, an event suggesting that the first inoculum might contain the same NANB hepatitis agent as the concentrate of factor VIII, which was supported by results of a subsequent cross-challenge experiment. Reinfection did not occur in two chimpanzees injected with their initial challenge strain of NANB hepatitis virus, providing evidence that strain-specific immunity had been established. Thus, experimental evidence is provided for the presence of two NANB hepatitis agents, supporting clinical and epidemiologic studies that favor the existence of more than one etiologic agent.

Alanine Transaminase↗
PubMed1979

Angiotensin convertase activities in human alveolar macrophages: effects of cigarette smoking and sarcoidosis.

Angiotensin I convertase activity has been found in human alveolar macrophages from normal volunteers and patients with pulmonary sarcoidosis. This activity is higher in the alveolar macrophages from smokers than from nonsmokers, and is even more elevated in sarcoid patients. The activity can be detected with both angiotensin I and bradykinin analogs and appears to require protein synthesis, but the enzyme is not secreted by alveolar macrophages in culture.

Granuloma↗
PubMed1979

Binding of beryllium to nuclear acidic proteins.

In vitro beryllium (Be) binding to rat liver nuclei has been reassessed (KAss = 2.0 X 10(6) M: n = 17 nmol Be/mg protein). Be also binds to rat liver nucleoli (KAss approx. 4 X 10(6) M: n = 10 nmol Be/mg protein). Examination of rat liver chromatin fractionated on a hydroxyapatite column shows that Be does not bind to histone or to the non-histone protein eluted by 0.05 M sodium phosphate. Be is strongly bound to the non-histone proteins eluted by 0.2 M sodium phosphate (KAss = 1.1 X 10(6) M: n = 55 nmol Be/mg protein) and also to the same extent to the fraction containing DNA which is subsequently eluted from the column. Evidence is provided that the latter binding is not due to DNA. The fractions containing the Be-binding proteins also contain the proteins which are phosphorylated to the greater extent.

Animals↗
PubMed1978

Metabolic responses of females to high intensity interval training of different frequencies.

The purpose of this investigation was to examine the effects of frequency and distance of high intensity, interval training on females. Thirty-two females participated in an eight-week program of interval run training. Subjects were assigned to either a 2 day/week or a 4 day/week group, as well as a high intensity, short distance (50,101,201 meters), or high intensity longer distance (604, 805, 1208 meters) group. Estimates of training intensity were 170% and 130% Vo2max for the short and longer distance groups, respectively. Maximal and submaximal measures of oxygen consumption (Vo2), heart rate (HR), and venous blood lactic acid were determined prior to and following the training program. After training, there was a significant increase (P less than 0.01) in Vo2max (13%) (deltax = 0.32 1/min or 5.2 ml/kg.min). Maximal VE increased approximately 12% after training (P less than 0.01). Max HR, max lactic acid, and submax Vo2 were not altered by the training. However, HR submax decreased significantly (P less than .05) after training by approximately 6%. Analysis of coveriance indicated that these changes were independent of training frequency, distance, and intensity. It was concluded that the changes in aerobic power and submaximal HR of females are independent of frequency, distance, and intensity of high-intensity interval training programs.

Adult↗
PubMed1977

Responses to moral dilemmas in medical students and psychiatric residents.

There has been an increasing interest in the area of medical ethics as indicated not only by the recent proliferation of books and articles but also in the re-emergence of crucial moral issues such as euthanasia, abortion and the like. The difficulty with the existing literature is that these reports are often descriptive, anecdotal and situationally relative to the decision maker. In this study, the authors utilized a cognitive developmental approach to studying responses to moral situations not only because this approach is cross-culturally universal but also because it is not subject to situational variables. In this regard, the results of the assessment of medical students and psychiatric residents are presented as well as a comparison of moral reasoning stages in relation to the C.M.A. Code of Ethics. Recommendations for further research are presented.

Codes of Ethics↗