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Biomedical subjects

M J Stewart

Publications and source records attributed to M J Stewart.

At least 127 records · Page 7Linked to original sources
PubMed1990

Professional interface with mutual-aid self-help groups: a review.

The ideal interface between self-help group and professional being of both theoretical and practical interest, this paper reviews the conceptual underpinnings of the interface issue and empirical studies in which the professional or self-help group member perspective on this issue was elicited or comparative analyses were conducted. Empirical studies measuring self-help group members' perceptions and studies of professionals' views indicate that professional interaction with self-help groups is desirable but that professional lack of information concerning self-help groups and lack of preparation for appropriate roles are perceived as barriers to such interaction. These studies clearly show that the indirect, non-authoritarian role of the professional as consultant receives the most support. Consultation and collaboration are recurrent themes in the empirical investigations of the professional interface with self-help groups. Balance and exchange theories could provide useful theoretical foundations for this collaborative practice. Clearly, educational preparation is needed to enable health professionals to embark on the essential transition from provider to partner with self-help groups.

Attitude of Health Personnel↗
PubMed1990

An NMR compatible model for solid tumour.

An NMR model for the study of drug interactions with solid tumour is described. It is based on the use of packed cells in a simple medium. The system is capable of dealing with cellular biochemistry at a molecular level through experiments conducted in a homogeneous field by 1H spin-echo NMR spectroscopy. However, through a simple imaging technique, it is also possible to introduce a spatial element into the chemistry of the packed cells. The use of these complementary NMR methods are illustrated by the action of the cytotoxic agent doxorubicin on cellular glycolysis. A pattern of signals observed in a homogeneous field experiment following oxidative stress are duplicated in the imaging experiment to illustrate the toxins' ability to penetrate the model tumour.

Antineoplastic Agents↗
PubMed1990

From provider to partner: a conceptual framework for nursing education based on primary health care premises.

An emerging need to educate nurses in innovative ways of working that respond to and interact with informal support networks was discerned. Accordingly, this study's purpose was to develop a conceptual framework for undergraduate nursing education that manifests a primary health care philosophy of consumer input and collaboration with lay helpers. This was predicated in part on a review of social-support theoretic premises, other theories germane to social support, and existing conceptual frameworks for the nursing discipline. Sixteen assumptions were developed and the four components of nursing's metaparadigm were defined to reflect primary health care premises of professional partnership with laypersons. Twenty core concepts were derived from social-support supplementary theories. A connecting structure was developed through creation of 20 relationship statements and 2 figures. The framework was favorably, albeit tentatively, evaluated against preselected criteria.

Education, Nursing↗
PubMed1990

trans activation of human alcohol dehydrogenase gene expression in hepatoma cells by C/EBP molecules bound in a novel arrangement just 5' and 3' to the TATA box.

A promoter sequence between nucleotide -51 and nucleotide -10 in the human alcohol dehydrogenase gene ADH2 has been shown to bind the transcription factor CCAAT/enhancer-binding protein (C/EBP). A series of 5'-end deletions of the ADH2 promoter was cotransfected with a C/EBP expression plasmid in a human hepatoma cell line, and trans activation by C/EBP was seen when at least 171 base pairs of 5'-flanking DNA was present. Mutations in the ADH2 promoter indicate that the mechanism of C/EBP trans activation involves two binding sites, one located just upstream of the TATA box and one located in an unusual location between the TATA box and the transcription start point.

Alcohol Dehydrogenase↗
PubMed1990

Plasmodium sporozoite-host cell interactions during sporozoite invasion.

In vitro and in vivo studies were performed to clarify the nature of some interactions between Plasmodium berghei sporozoites and rodent host cells. Videomicroscopic observations were made on in vitro interactions between sporozoites and cultured host cells (rodent peritoneal macrophages, W138 human lung fibroblasts, and HepG2 human hepatoma cells). The results showed a diversity of dynamic interactions and sporozoite activities, including active sporozoite penetration, often followed by sporozoite escape, killing of invaded macrophages, phagocytosis of sporozoites by macrophages, and elaboration of a weblike structure by the sporozoite, following its escape from cells. Other studies were performed to examine host cell inflammatory responses to challenge sporozoites in the livers of rats that had been previously immunized with radiation-attenuated sporozoites. The results showed a variety of focal inflammatory infiltrates in the livers of the challenged animals. The relevance of these observations to the problems of sporozoite invasion into natïve and immunized animals is discussed.

Animals↗
PubMed1990

Home or hospital care for acute myocardial infarction? A survey of general practitioners' attitudes in the thrombolytic era.

This study examines the issue of whether to give home or hospital care to patients with suspected myocardial infarction now that the value of thrombolytic therapy has been recognized. A questionnaire survey of 69 general practitioners showed that the majority were aware of the potential benefits of thrombolysis although few thought that these extended beyond six hours after the onset of symptoms. Most would opt for hospital care for patients under the age of 70 years, but would treat older patients with uncomplicated myocardial infarctions at home, depriving them of the opportunity to receive thrombolysis. The admission policies of general practitioners for patients with suspected myocardial infarction merit reappraisal so that thrombolysis can be considered for all patients up to 24 hours after the onset of symptoms.

Aged↗
PubMed1989

The Drosophila melanogaster RPS17 gene encoding ribosomal protein S17.

A human ribosomal protein S17 cDNA [Chen et al., Proc. Natl. Acad. Sci. USA 83 (1986) 6907-6911] was used as heterologous probe to isolate S17 clones from Drosophila genomic and cDNA recombinant libraries. Five S17 genomic clones were recognized; all contained overlapping regions of a single chromosomal site. Subsequently the Drosophila RPS17 gene was mapped by in situ hybridization to chromosome 3L, band 67B1-5. The locus spans approximately 1000 bp of DNA and includes four exons. It is preceded by conventional CAAT and TATA RNA polymerase II promoter motifs. The 131 amino acid protein encoded within Drosophila RPS17 is similar to ribosomal proteins from several other eukaryotes. Comparison of eukaryotic S17 proteins' primary structures as well as the number and location of their genes' intervening sequences suggest that S17 is a relatively recent addition to the ribosomal protein family, probably post-dating divergence of eukaryotes and prokaryotes.

Amino Acid Sequence↗
PubMed1989

Social support intervention studies: a review and prospectus of nursing contributions.

Nurse researchers have contributed some conceptual clarity, measurement devices and empirical studies of support resources and target populations to the social support literature. One apparent deficit, surprising when one considers nursing's practice-orientation, is the virtual absence of empirical intervention studies. Accordingly, potential foci for nursing investigations at five levels of social-support interventions (individual, dyadic, group, social system and community levels) are proposed here. Nurses can not only propose but can also validate concepts of social support in real-life situations with real-world populations. They are qualified to bring a unique perspective to the study of social support. Empirical intervention research conducted by appropriately educated nurses should enhance future theoretical and practical development of the social support field.

Adaptation, Psychological↗
PubMed1989

Target populations of nursing research on social support.

Nurses contribute to the social support field primarily through study of clinical and community populations. A review of the target populations identified in 63 empirical studies of social support conducted in the past decade revealed that nurses have, to date, studied populations central to their profession's activities and concerns. They have uniquely focused on surgical patients, the chronically ill, expectant couples and parents of infants, the bereaved, and lay caregivers. These target groups have suffered from maturational (transitional) and/or situational stressors. However, some at-risk groups have been overlooked; in particular, children, males only, native peoples, the poor, the unemployed, and the victims of child and elder abuse. Nurses practice in diverse institutional and community-based sites, and hence have direct contact with all these population groups. Once the features of a population that make it a fruitful focus of study by nurse investigators are identified, pertinent interventions can be tested.

Aged↗
PubMed1989

Social support: diverse theoretical perspectives.

The useful predictions and interpretations about social support which can be derived from attribution, coping, equity, loneliness and social comparison theories have typically not been recognized. Attribution theory can enable explanation of motives of donors, the phenomena of help-seeking and helping, and negative effects of support efforts. Coping theory demonstrates how social support and coping interface in the stress process; adds a cognitive dimension to support; and considers costs of support. Equity theory explains reactions to support from donor and recipient viewpoints and the reciprocal nature of social support. Loneliness theory attests to the significance of social relationships and emphasizes the affective dimension of support. Social comparison theory is helpful in interpreting positive and debilitating effects of support when the donor is a peer. Further, these five theories enhance theoretical interpretation of social support through their distinctive explanations of the concepts of 'appraisal' and 'helping'. Relevance to health professional assessment and practice can be delineated.

Adaptation, Psychological↗
PubMed1989

Comparison of microscale ultracentrifugation and equilibrium dialysis for the determination of the unbound fraction of theophylline in human serum.

A microscale ultracentrifugation procedure for the measurement of free theophylline in serum is described and evaluated by comparison with an equilibrium dialysis method. Provided an ultracentrifuge is available, micro-ultracentrifugation is a simple, cost-effective technique for the routine determination of free drug fractions.

Costs and Cost Analysis↗
PubMed1988

Doxorubicin-induced altered glycolytic patterns in the leukemic cell studied by proton spin echo NMR.

1H spin echo NMR of the leukemic cell line J-lll is reported. Phosphorylcholine, phosphorylcreatine, lactate and mobile triglyceride are identified as constituents of the cytosolic pool in the intact and viable cells. The concentration of cells in the NMR tube is high (approx. 10(9) in 0.4 ml) and as a result the available oxygen is restricted, making the NMR experiment a plausible in vitro tumour model in which kinetics in the living cell can be probed in a non-invasive manner. Treatment with pharmacological concentrations of the drug doxorubicin produced immediate enhanced anaerobic glycolysis and eventual cell death.

Doxorubicin↗
PubMed1988

The use of 1H spin echo NMR and HPLC to confirm doxorubicin induced depletion of glutathione in the intact HeLa cell.

The effects of doxorubicin on the cellular biochemistry of the HeLa cell using 1H spin echo nuclear magnetic resonance spectroscopy (NMR) of the intact and viable cell in conjunction with dual wavelength HPLC of cell lysates is reported. Directly dose-related changes were observed in lactate and reduced glutathione concentration. Doxorubicin induces a time-dependent depletion of the cytosolic pool of glutathione and a change in the glycolytic pattern of the cell. The glutathione depletion could be partially reversed by controlled pre-treatment of the cells with N-acetylcysteine and cysteine, the protection being linked to the intracellular concentration of the thiol.

Acetylcysteine↗
PubMed1988

Does biased gene conversion influence polymorphism in the circumsporozoite protein-encoding gene of Plasmodium vivax?

Variation between North Korean and Latin American isolates in the circumsporozoite (CS) protein encoding gene of the human malaria parasite Plasmodium vivax was studied. Polymorphic positions are confined to the central tandemly repeated sequences. Nucleotide substitutions in the tandem repeats produce variants; these substituted positions within the repeat array tend to be conserved between genes. The North Korean CS gene has a short insertion after the repeats encoding a 4-amino acid repeat (Ala-Gly-Gly-Asn) not found in the New World P. vivax genes. This sequence is found both flanking and within the tandem repeats of the CS genes of several strains of the Southeast Asian simian malaria parasite, Plasmodium cynomolgi. The intraspecific conservation of positions of variants within tandem repeat arrays and the interspecific conservation of probably ancestral repeat motifs at the end of these arrays are consistent with the occurrence of nonreciprocal genetic exchanges between the tandem repeats of these genes. However, a striking asymmetry in strand nucleotide composition within the tandem repeats of all CS genes leads us to suggest that biased correction of heteroduplexes formed during recombination plays a role in the evolution of these genes.

Amino Acid Sequence↗