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D Mitchell

Publications and source records attributed to D Mitchell.

405 records · Page 23Linked to original sources
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12 steps to heaven?

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Humans↗
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Is prostaglandin E the neural mediator of the febrile response? The case against a proven obligatory role.

We have reviewed the evidence in favor of a prostaglandin mediator of the thermal responses in fever and found that PGE injected into the hypothalamus does not always cause fever, that cerebrospinal fluid concentrations of PGE are not reliable reflections of hypothalamic events, and that antipyretic drugs may act in ways other than inhibiting PGE synthesis. Fever is not blocked by prostaglandin antagonists, nor by ablation of PGE-sensitive areas of the brain. There is poor correlation between the effects of pyrogens and of PGE on cerebral neurons. There is evidence that at least one prostanoid other than prostaglandin is a mediator of fever, but the prostanoid has not been identified yet. We conclude that PGE may contribute to the neural responses in fever but is not essential.

Animals↗
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Conditioned taste aversions accompanied by geophagia: evidence for the occurrence of "psychological" factors in the etiology of pica.

A conditioned taste aversion procedure was used to produce an avoidance of saccharin by rats. In the first experiment, saccharin consumption was paired with cyclophosphamide in two conditioning trials during which the animals were permitted to engage in pica. In the second experiment, saccharin consumption was paired with lithium chloride in four conditioning trials during which the animals were not allowed to engage in pica. Conditioned animals in both experiments subsequently engaged in geophagia when presented with saccharin alone. The absence of geophagia in noncontingently poisoned and "sham" injected control groups indicates that the pica was due to the acquisition of a conditioned illness during the conditioning trials. In addition to providing a demonstration of "psychological" involvement in the etiology of pica, these results indicate that visceral conditioning may accompany the formation of conditioned taste aversions. It is suggested that if there is a relationship between infantile pica and adult drug addiction, a plausible mediational mechanism is that pica-prone and addiction-prone individuals are similar in possessing a high susceptibility to visceral conditioning.

Animals↗
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Inhibition of ultraviolet light induced skin carcinogenesis in SKH-1 mice by apigenin, a plant flavonoid.

Apigenin, a widely distributed plant flavonoid, was previously found to inhibit chemically induced ornithine decarboxylase (ODC) activity and skin tumor promotion. The purpose of the present research was to determine if apigenin is effective in the prevention of ultraviolet-B light (UVB) induced skin carcinogenesis. Further studies ascertained if apigenin would be expected to absorb UVB light in a manner to prevent DNA damage in a cell free system. ODC activity was induced with 0.45 J/cm2 ultraviolet A and B (UVA/B) light. Apigenin (5 mumoles/200 microliters DMSO:acetone, 1:9) treatment from 12 hours before until 1 hour following UVA/B exposure was effective in inhibition (25-45% inhibition) of ODC activity measured at 28 hours following UVA/B exposure. Mouse skin carcinogenesis was induced by exposure to a total dose of 40 J/cm2 UVB over 11 weeks. Treatment with 10 mumoles apigenin in 200 microliters DMSO:acetone (1:9) prior to each UVB exposure resulted in reduction in cancer incidence (52% inhibition) and an increase in tumor free survival in comparison with control mice (P < 0.01). Apigenin (0-100 microM) did not prevent the in vitro production of photoproducts in salmon sperm DNA suggesting that apigenin did not inhibit UVA/B induced ODC activity or UVB induced skin carcinogenesis by simply absorbing ultraviolet light or decreasing DNA damage.

Animals↗
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Understanding learning styles. Implications for staff development educators.

The authors present information for understanding diverse learning styles among RNs. Various learning-style assessment tools are presented. Emphasis is placed on the use of a learning-style instrument that addresses multiple learning-style constructs. Implications for staff development educators are discussed.

Education, Nursing, Continuing↗