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Biomedical subjects

D Taylor

Publications and source records attributed to D Taylor.

At least 451 records · Page 25Linked to original sources
PubMed1985

A new vacuum-operated stress-providing instrument that applies static or variable duration cyclic tension or compression to cells in vitro.

An instrument providing cyclic stress to cells cultured in vitro has been developed. The unit uses a vacuum to deform a plastic Petri dish yielding 0.13% compression to cells on the inner surface, measured by strain gauge recordings. A regimen of 25 s stress and 5 min relaxation induced no significant change in synthesis of a 45 X 10(3) Mr protein that comigrates with actin, whereas a 52 X 10(3) Mr protein that comigrated with tubulin decreased from 12.7 +/- 0.451% of the total protein synthesized in control, static cells to 8.53 +/- 0.182% in stressed cells. The unit may have a broad application in monitoring biochemical changes in response to stress in cells such as muscle, lung, tendon, ligament and bone that are normally subjected to tension or compression.

Animals↗
PubMed1985

Screening?

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Age Factors↗
PubMed1984

Rapidly progressive posthemorrhagic hydrocephalus. Treatment with external ventricular drainage.

Nineteen premature infants with progressive posthemorrhagic hydrocephalus with increased intracranial pressure were treated with external ventricular drainage. Progression of hydrocephalus was arrested during the drainage period in each patient. Three of the 19 infants required no further therapy. Sixteen had recurrence of progressive ventricular dilatation, and all but one eventually had placement of a ventriculoperitoneal shunt, although under more favorable medical conditions than existed at the time of institution of external ventricular drainage. Three of the 19 infants died of causes unrelated to the external ventricular drainage. Of the 16 survivors, seven infants had a developmental quotient or formal IQ of over 75. Outcome was poorest for those infants with accompanying intracerebral hemorrhage. We consider ventriculostomy to be an effective temporizing measure in small infants with rapidly progressive posthemorrhagic hydrocephalus with increased intracranial pressure in whom ventricular decompression is necessary and placement of a ventriculoperitoneal shunt is not feasible.

Catheterization↗
PubMed1984

Regulation of mitotic activity and the cell cycle in primary chick muscle cells by neurotransferrin.

We previously demonstrated that neurotransferrin (NTF), a transferrin extracted from adult chicken peripheral nerves, promotes growth of primary chick muscle cells in the absence of embryo extract. NTF was shown to stimulate DNA synthesis and cell proliferation. In the present study, we demonstrate that NTF is a mitogen using two independent methods; counts of orcein-stained mitotic figures and analysis of cell cycle kinetics with a fluorescence-activated cell sorter. In low-density cultures mitotic activity increases with increasing doses of NTF followed by a plateau at concentrations greater than 6 micrograms/ml. Residual, embryonic mitotic activity progressively declines with time after plating muscle cells in the absence of NTF. Absence of NTF for 2 days causes cells to lose irreversibly their myogenic potential. In the presence of NTF, mitotic activity increases for 2 days followed by a decline concurrent with myoblast fusion and formation of myotubes. Cell cycle analysis showed that NTF addition causes cell populations to shift from G1 to S and G2 + M within 18.5 hr. Muscle cells, plated at high densities in the absence of NTF, show mitotic activities similar to those plated at low densities in the presence of NTF. Addition of NTF to high-density cultures is ineffective in stimulating mitosis. These studies show that at typical cell plating densities, NTF is a required mitogen for primary chick muscle cell cultures.

Animals↗
PubMed1984

Control of nucleic acid and protein synthesis in developing brain, kidney, and heart of the neonatal rat: effects of alpha-difluoromethylornithine, a specific, irreversible inhibitor of ornithine decarboxylase.

Ornithine decarboxylase (ODC) and the polyamines are thought to play a role in maturation of mammalian tissues. Daily postnatal administration of alpha-difluoromethylornithine (DFMO, a specific inhibitor of ODC) to newborn rats caused organ-specific deficits in tissue weight gain, with brain and kidney as the major targets. Subnormal organ weights were associated with deficits in the levels of nucleic acids and proteins in the affected tissues, and examination of the synthetic rates of DNA ([3H]thymidine incorporation), RNA ([3H]uridine incorporation) and protein ([14C]leucine incorporation) confirmed that macromolecule synthesis was inhibited in DFMO-treated pups. The time of onset of effect of DFMO on the synthesis of nucleic acids and proteins was the same as that reported for depletion of polyamines by this treatment. Potential adverse effects of DFMO on cell survival were also assessed by labeling DNA with [3H]thymidine on day 3 and examining retention of label 12 days later; DFMO did not cause an increase in cell death. In contrast to the sensitivity of brain and kidney to postnatally administered DFMO, development of cardiac tissue was relatively resistant to growth inhibition despite polyamine depletion. The organ specificity of effect of DFMO results, in part, from the different timetables for cellular events in tissue development displayed by each organ type; administration of DFMO earlier in development (during days 15 to 17 of gestation) did produce deficiencies in cardiac growth and nucleic acid levels similar to those which had been seen for brain and kidney. These data support the view that polyamines play a key role in cell replication, differentiation and growth during critical periods of mammalian organ development through their regulation of DNA, RNA, and protein synthesis.

Animals↗
PubMed1984

Which computer?

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Computers↗
PubMed1984

Mixed lymphocyte culture responses. Lack of correlation with cadaveric renal allograft survival and blood transfusions.

One-way and two-way mixed lymphocyte reactions (MLRs) between 65 cadaveric renal allograft recipients (R) and their specific-donor (D) and pooled third-party (P) cells were measured using a 5-day assay. There was no correlation between the results expressed as stimulation index, absolute counts, or the relative response and graft survival in transfused allograft recipients. Nontransfused recipients whose first graft failed had significantly higher responses to P, but not D, than those with successful grafts. The one-way MLRs to P of 61 cadaveric graft recipients and 52 potential recipients were measured. No correlation was found between the magnitude of the response and the number of transfusions, time since the last transfusion, or peak cytotoxic antibody production. Our results suggest that a standard 5-day MLR has little clinical value in predicting the results of cadaveric transplantation in HLA-A,B-mismatched recipient-donor pairs. We could not demonstrate any overall effect of transfusions on the MLR, suggesting that this may not be the mechanism by which transfusions exert their effect on graft survival.

Adolescent↗
PubMed1983

Smoking: the group.

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Community Health Nursing↗
PubMed1983

The significance of the accumulation of cadmium by aquatic organisms.

Cadmium, by virtue of its toxicity, persistence, and bioaccumulation appears on the "black list" of all the international conventions aimed at protecting the aquatic environment from pollution. Although there is no doubt that cadmium is both persistent and toxic to aquatic life at relatively low concentrations, its bioaccumulation potential appears to have been somewhat exaggerated. Median concentration factors for both marine and freshwater organisms are less than 100 times and for vertebrate (fish) species concentration factors are less than 20 times. There is no evidence in the literature for biomagnification of cadmium and bioconcentration is only likely to be of significance in a restricted range of gastropod mollusks and some crustacea.

Animals↗
PubMed1983

A physical comparison of two fixed-angle emission tomographic cardiac imaging systems.

Two 7-pinhole tomographic imaging systems for large and small field-of-view gamma cameras were compared with a standard rotating slant-hole system in terms of planar resolution and resolution with depth. Other measurements include the determination of the depths of the reconstructed planes, image miniaturization and scintislice area variation with depth, the effect of scatter on resolution and the variation in resolution across the reconstructed plane. The pinhole sensitivities and the relative reconstructed sensitivities with depth were also measured. The rotating slant-hole system is found to have better depth resolution, a better scatter correction, has more uniform reconstructed sensitivities, is easier to position over the patient but requires significantly longer data acquisition times than the 7-pinhole system.

Heart↗
PubMed1983

Reflections on parenting: a multigenerational perspective.

This paper presents some of the underlying patterns of parenting that have emerged from six years of ethnographic field research into the role of the family in children's acquisition and use of reading and writing skills. The research has provided some insights into the many complex and interrelated ways that children's literate activities are mediated and affected by multigenerational family patterns and by their personal experience of everyday life both within and outside the family. Two central themes are discussed: the spirit of change, which breaks the patterns of the past and brings new interpretations into the present, and the spirit of conservation, which maintains the continuation of family patterns from one generation to the next. Also described are the important parental attitudes of social flexibility and resiliency that are frequently evident in these processes of conservation and change of multigenerational patterns. One specific family story provides the background for the theoretical issues that are explored.

Adaptation, Psychological↗