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Biomedical subjects

M C Clark

Publications and source records attributed to M C Clark.

32 records · Page 2Linked to original sources

Social support, perceived control, and well-being: a study of an environmentally stressed population.

Interviews were conducted with elderly residents of an area targeted for massive redevelopment. Social support was considered simultaneously with health and personal control beliefs in relation to well-being, and the unresolved issue of the sufficiency of one support figure was explored. Health, control, and support each emerged as independent predictors of after and life satisfaction, and affect was significantly lower for those with no close support figure than for those with one close relationship. The results suggest that one close support figure may be sufficient to promote well-being, but alternative interpretations are possible.

Aged↗

Characterization of a plasmid in isolates of Corynebacterium sepedonicum.

Lysis of mid-log phase cells of the Gram-positive bacterium, Corynebacterium sepedonicum, by a combination of lysozyme treatment and incubation with alkaline sodium dodecyl sulfate at 56 degrees C led to the recovery of a single plasmid. The plasmid was purified in CsCl density gradients, and its molecular weight estimated to be 31 megadaltons (46 kilobases), as determined from its relative mobility in agarose gels, from its contour dimensions in electron micrographs, and from the size of the fragments generated when it was cleaved with various restriction endonucleases. Thirteen widely divergent isolates of C. sepedonicum were screened for the presence of plasmid, and of these, 11 were shown to harbour a single plasmid at a level of about 30 copies per cell. Cleavage of the plasmid with PstI gave an identical banding pattern in agarose gels for the fragments from all of the plasmid-carrying isolates. The relevance of plasmid incidence and distribution in C. sepedonicum is discussed in relation to the possibility of developing a test for the detection of bacterial ring rot by using plasmid DNA as a hybridization probe.

Corynebacterium↗

Comparison of the echocardiographic and hemodynamic diagnosis of rheumatic tricuspid stenosis.

Two-dimensional echocardiography has proved to be reliable in the diagnosis of mitral, aortic and pulmonary stenosis. Its role in the diagnosis of rheumatic tricuspid stenosis is still being defined; therefore, the tricuspid valve echograms of 147 patients with rheumatic heart disease were examined. Thirty-eight of these patients also underwent hemodynamic evaluation. Tricuspid stenosis was defined echocardiographically as diastolic anterior leaflet doming, thickening and restricted excursion of the other two tricuspid leaflets and decreased separation of the leaflet tips. Using these criteria, the sensitivity and specificity of the echocardiogram in detecting tricuspid stenosis were 69 and 96%, respectively, in the group of 38 patients who had both echocardiographic and hemodynamic evaluations. However, when the smaller group of 17 patients who had simultaneous right atrial and right ventricular pressure recordings were considered separately, there was complete agreement between the echocardiographic and hemodynamic data. Thus, the two-dimensional echocardiogram is a sensitive and specific test for diagnosing rheumatic tricuspid stenosis. In addition, these data provided an opportunity to determine the prevalence of tricuspid stenosis in this group of patients with chronic rheumatic valvular disease. Tricuspid stenosis was present in 14 (9.5%) of the total group of 147 patients who had two-dimensional echocardiograms, and in 10 (26.3%) of the 38 who had both echocardiographic and hemodynamic studies. In patients with rheumatic heart disease about to undergo cardiac catheterization, an echocardiographic study should prove useful in making the diagnosis of tricuspid stenosis.

Adult↗

Permeability pulmonary edema caused by venous air embolism.

A 22-yr-old man developed severe pulmonary edema after blowing air into tubing connected to a catheter inserted in a vein in his forearm. Pulmonary edema was rapid in onset, peaking in intensity about 12 h after the air had been insufflated. The patient's edema fluid to plasma protein concentration ratio of 0.79 showed that the edema fluid was rich in protein. Vascular pressures were normal except for mild pulmonary arterial hypertension and systemic hypotension. The patient's clinical course, edema fluid protein concentration, and vascular pressures were characteristic of an increased microvascular permeability type of pulmonary edema. The patient recovered fully within 48 h of the air infusion. His response to venous air embolism was similar to findings in an experimental model of pulmonary edema in sheep infused with venous air emboli. As long as air is not infused continuously for long periods or in very large amounts, this disorder is probably self-limiting, and supportive care may be the only treatment necessary.

Adult↗

Purine metabolism and differential inhibition of spore germination in Phytophthora infestans.

An analysis of the effect of various purines and pyrimidines on the germination process in three different isolates of the late blight fungus, Phytophthora infestans, revealed increased rates of indirect germination in one isolate by adenine, hypoxanthine, and the riboside of dimethylaminopurine. This observation coupled with the capacity of sporangia of the race affected (1.2.3.4) for the uptake and interconversion of purines, as demonstrated by experiments with labelled purines under in vivo and in vitro conditions, pointed to hypoxanthine as a key intermediate in the purine metabolism directly associated with spore formation and development. This enhanced germination contrasted sharply with the almost complete arrest of indirect germination that occurred when sporangia were incubated with the purine analogue, benzimidazole, or with either of the respiratory inhibitors, sodium azide and 2,4-dinitrophenol. The pattern of differential inhibition exhibited by sporangia versus zoospores upon treatment with actinomycin D, 4-FLUOROURACIL, OR CYCLOHEXIMIDE INDICATED THat continued translation on preformed messenger RNA may be one essential requirement for the formation and release of zoospores, whereas their subsequent germination and development may depend upon renewed transcription as well.

Azides↗

Women's self-perception and self-care practice: implications for health care delivery.

Mexican American women experience unique health care needs related to integration of Mexican and American cultures. To learn how to better promote self-care practices and service utilization in women of Mexican origin living in Texas, researchers used a qualitative approach to interview a convenience sample of 11 low-income women attending a health clinic. Researchers collected narrative data about the women's perceptions of health, wellness, and self-care. Using the matrix approach described by Miles and Huberman, we organized findings around women's roles, including participants' descriptions of themselves, their health and wellness awareness, self-care practices for health/illness and wellness/nonwellness, barriers to self-care, origin of self-care practices, and perceptions of life control. Implications for health planning and service delivery are presented.

Adult↗

Social support and well-being: preliminary indicators based on two samples of the elderly.

The structure of social support and its relation to health, affect, and life satisfaction are compared for two samples of the elderly. The first is a national representative sample; the second is a distressed sample from South Miami Beach. Although there are similarities in the structure of social support across the two groups, those in the Miami Beach sample report fewer support figures, and far fewer within geographic proximity, than do those in the national sample. This comparative network impoverishment is particularly marked for male respondents and is accentuated by a high number of isolates in this group. In addition, stronger relationships are found between support network size and affect, and among affect, life satisfaction, and health in the South Miami Beach sample. Older men in poor health and without supportive relationships are targeted as a particularly high risk subgroup. The discussion includes a focus on personal, situational, and life span differences related to variations in support and well-being and a consideration of implications for more recent waves of elderly sun-belt migrants.

Affect↗

The caregiving story: how the narrative approach informs caregiving burden.

The burdens of giving care to a chronically ill or dependent family member can be overwhelming. The therapeutic utilization of narrative can assist elderly female caregivers to transform their feelings of depression and burden into a healthy acceptance of the required care and disabilities of the elder for whom they care. This technique, which assists clients to restory negative aspects of their perceived reality, has emerged from the theoretical framework of postmodernism. Using the narrative approach to a family case study involving a daughter and dependent mother, this article examines interventions that can facilitate the positive development of a client's caregiving story.

Adaptation, Psychological↗

Perfluorocarbons: future clinical possibilities.

Perfluorocarbons are now being used as oxygen carriers in clinical settings. Because these chemicals may have a role as a blood substitute, in organ preservation, and in the management of respiratory failure, we have reviewed some of the research leading to these applications.

Biological Transport↗

Chest pain.

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Adult↗

Enhancing critical-thinking skills: faculty-student partnerships in community health nursing.

The enhancement of critical-thinking skills empowers students to participate in the building of healthy environments in a variety of settings. The authors describe the development and implementation of unique classroom strategies emphasizing the use of critical thinking by students, the forging of faculty-student partnerships in community health nursing, and the potential impact of these strategies on the expanding horizons of practice.

Clinical Competence↗