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Biomedical subjects

R S Duff

Publications and source records attributed to R S Duff.

At least 19 recordsLinked to original sources
PubMed1992

Coordination of ATP production and consumption in brain: parallel regulation of cytochrome oxidase and Na+, K(+)-ATPase.

Previous studies have shown that most neuronal ATP is produced by oxidative metabolism, and consumed by Na+,K(+)-ATPase. We hypothesized that the distribution of Na+,K(+)-ATPase in brain would correlate with that of the energy-producing enzyme, cytochrome oxidase (CO). We localized these enzymes in monkey hippocampus and striate cortex by histochemistry and immunohistochemistry. Their distributions were generally similar, although some differences were observed. We also studied regulation of enzyme levels, using monocular impulse blockage with tetrodotoxin (TTX) to alter neuronal activity in the visual system. Parallel changes in CO and Na+,K(+)-ATPase activity were induced in striate cortex. These results provide further evidence that neuronal energy demands regulate CO levels and distribution.

Adenosine Triphosphate↗
PubMed1991

In vitro clonal analysis of progenitor cell patterns in dorsal root and sympathetic ganglia of the quail embryo.

The possible presence of pluripotent cells in dorsal root (DRG) and sympathetic ganglia (SG) of the quail embryo has been investigated by in vitro clonal analysis. Both types of ganglia originate from the neural crest. At, or soon after, initiation of emigration from the neural tube, the neural crest appears as a mixed population of pluripotent cells and cells with more restricted developmental capacities. In the present study it was determined that pluripotent cells and precursor cells with restricted developmental potentials are also present in early DRG and SG, and that their proportions change with progressing age of the embryo. As in the neural crest, cells in one class are at least tripotent, able to give rise to pigment cells, sensory neurons, and cells in the sympathoadrenal lineage. Cells in the other class appear to have lost the melanogenic potential, but generate cells in the sensory neuron and sympathoadrenal lineages. In addition, there are two types of cells that seem to be committed to the melanogenic and sensory neuron lineages, respectively. Apparently committed melanogenic cells within the DRG are not detected after the first third of embryonic development, whereas precursor cells that are at least bipotent and generate both types of neurons persist in both DRG and SG at least through the first half of embryonic development. Neurogenic cells that are apparently committed to the sensory neuron or sympathoadrenal lineages were observed in the appropriate type of ganglion only, suggesting that location-specific cues influence the choice of phenotype generated by pluripotent neural crest cells.

Animals↗
PubMed1981

Counseling families and deciding care of severely defective children: a way of coping with 'Medical Vietnam'.

Medical paternalism supported by hospitals and courts has been, will be, and should be used in those few situations where clearly incompetent or irresponsible parents resist treatment that health professionals generally agree is needed and effective. If used in other circumstances, it is likely to erode family and professional autonomy and bring about an oppressive "medical Vietnam" (costly, sometimes abusive, use of technology to ensure biologic existence with little regard for quality of child and family life and competing interests). Families must be relied upon to help resolve most complex tragedies because there is no better alternative. They are likely to become stronger if they participate in decisions for care of their severely defective children. Such decisions logically include those for life or death.

Conflict, Psychological↗
PubMed1979

Guidelines for deciding care of critically ill or dying patients.

Medical technology is usually beneficial in the care of sick or injured persons, sometimes dramatically so. However, since it is often intrusive, occasionally cruel, sometimes of little or no value, and almost always expensive, its use must be assessed critically, particularly in ICUs. Guidelines for doing this are proposed. To ensure the most caring approach to patient care and family support, the values and autonomy of patients and their families, one by one, are emphasized in all decision making and the roles of nurses and social workers as well as those of physicians are considered central. If these guidelines are used, many, perhaps most, of the ethical and legal issues and the problems of human relationships in ICUs will be resolved.

Adolescent↗
PubMed1976

Symptomatic mitral myxomatous transformation in the elderly.

The clinical and pathological features of four patients with intractable heart failure, due to myxomatous change in the mitral valve, are described. It is suggested that this change may represent a response of ageing connective tissue to mechanical stress.

Aged↗
PubMed1976

On deciding the care of severely handicapped or dying persons: with particular reference to infants.

Two philosophies of deciding the care of severely handicapped or dying persons are commonly used. The first is "disease-oriented" which places death in the extreme negative position. The second is "person-oriented" which regards some kinds of severely compromised living as worse than death. The first philosophy is convenient for the development and the use of medical technology but its unbridled application commonly dehumanizes patients and aggravates suffering. The second philosophy may protect persons from the indignities of pointless treatment or the cruelties of disease. But its use in some respects is illegal and may be unwise; also, in caring for infants, children, and incompetent adults, the second philosophy creates special problems since the patient himself cannot participate in decision-making. In deciding which philosophy to follow in a given situation we believe the patient (when able), the sorrowing family, and the concerned physician are the best judges. Since these persons vary widely, they must be entrusted with more freedom to change or to ignore commonly accepted principles if the values of patients and families in the many unique situations of living, illness, and dying are to be protected. We believe with few exceptions that these persons are now worthy of this trust and with experience they would use it with growing wisdom.

Decision Making↗
PubMed1975

Evaluation of [3-H]proline for radioautographic tracing of axonal projections in the teleost visual system.

The efficacy of [3-H]proline radioautography for tracing retinal ganglion cell projections to the optic tectum of the jewel fish, Hemichromis bimaculatus, has been compared with that of degeneration techniques. There was good agreement between the various methods. Retinal projections to the optic tectum of two other teleosts, the oscar, Astronotus ocellatus, and the goldfish, Carrasius auratus, were examined radioautographically. In addition to conventional methods of analysis, radioautograms were scanned in a slit microdensitometer and by an automated isodensity scanning system. Results of studies with the protein synthesis inhibitor, cycloheximide, are compatible with the suggestion that axonally transported proteins labeled with [3-H]proline may release diffusible precursors that are reincorporated into protein in adjacent regions. The possible advantages and limitations of radioautography of [3-H]proline-labeled axonally transported protein in brief or extended studies are discussed in terms of the results obtained in the teleost visual system.

Animals↗
PubMed1975

A review of pediatric inpatient care.

Between 101 and 188 medical records of children hospitalized in each of three community hospitals and one major teaching hospital were examined to determine need for admission and quality of care administered. Two of the hospitals had been similarily studied two years before. Twenty-five percent of all admissions and 17% of all patient days were considered unnecessary. The smallest number of inappropriate admissions was found in the major teaching institution, but one of the community hospitals without any teaching affiliation was notably better than the other two. The teaching hospital and the same community hospital also achieved the lowest questionable management rates. Significant (P less than 0.5) but minimal reduction had occurred in number of unnecessary admissions when first and second utilization studies in these two hospitals were compared.

Child↗