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Biomedical subjects

R Cook

Publications and source records attributed to R Cook.

At least 145 records · Page 8Linked to original sources
PubMed1981

The same normal cell protein is phosphorylated after transformation by avian sarcoma viruses with unrelated transforming genes.

The phosphorylation of a normal cellular protein of molecular weight 34,000 (34K) is enhanced in Rous sarcoma virus-transformed chicken embryo fibroblasts apparently as a direct consequence of the phosphotransferase activity of the Rous sarcoma virus-transforming protein pp60src. We have prepared anti-34K serum by using 34K purified from normal fibroblasts to confirm that the transformation-specific phosphorylation described previously occurs on a normal cellular protein and to further characterize the nature of the protein. In this communication, we also show that the phosphorylation of 34K is also increased in cells transformed by either Fujinami or PRCII sarcoma virus, two recently characterized avian sarcoma viruses whose transforming proteins, although distinct from pp60src, are also associated with phosphotransferase activity. Moreover, comparative fingerprinting of tryptic phosphopeptides shows that the major site of phosphorylation of 34K is the same in all three cases.

Animals↗
PubMed1981

Effect of cortisol and dexamethasone on the oestrogen-induced release of luteinizing hormone in the anoestrous ewe.

The oestrogen-induced of LH in anoestrous ewes was used as a model for studying the effect that glucocorticoids have on the secretion of LH. It was found that neither the repeated administration of the synthetic glucocorticoid, dexamethasone, nor the infusion of cortisol blocked the oestrogen-induced release of LH in the anoestrous ewe. These findings indicate that, in the ewe, glucocorticoids do not alter the ability of oestrogen to induce LH secretion.

Anestrus↗
PubMed1979

Sensory extinction and sensory reinforcement principles for programming multiple adaptive behavior change.

The role of sensory reinforcement was examined in programming multiple treatment gains in self-stimulation and spontaneous play for developmentally disabled children. Two phases were planned. First, we attempted to identify reinforcers maintaining self-stimulation. Sensory Extinction procedures were implemented in which auditory, proprioceptive, or visual sensory consequences of self-stimulatory behavior were systematically removed and reintroduced in a reversal design. When self-stimulation was decreased or eliminated as a result of removing one of these sensory consequences, the functional sensory consequence was designated as a child's preferred sensory reinforcer. In Phase 2, we assessed whether children would play selectively with toys producing the preferred kind of sensory stimulation. The results showed the following. (1) Self-stimulatory behavior was found to be maintained by sensory reinforcement. When the sensory reinforcer was removed, self-stimulation extinguished. (2) The sensory reinforcers identified for self-stimulatory behavior also served as reinforcers for new, appropriate toy play. (3) The multiple treatment gains observed appeared to be relatively durable in the absence of external reinforcers for play or restraints on self-stimulation. These results illustrate one instance in which multiple behavior change may be programmed in a predictable, lawful fashion by using "natural communities of sensory reinforcement."

Autistic Disorder↗
PubMed1975

The attractiveness to males of female Drosophila melanogaster: effects of mating, age and diet.

Decapitated females were used to examine the attractiveness to males (duration of courtship elicited) of female Drosophila melanogaster. Decapitated females show but few behavioural responses. The attractiveness of virgin females varied with age, being at a maximum on the day of eclosion, and declining thereafter. Even though decapitated inseminated females do not extrude their genitalia they received less courtship than decapitated virgin females. In protein-fed inseminated females attractiveness to males returned in parallel with sexual receptivity. A sucrose diet rendered both virgin and inseminated decapitated females more attractive to males, but did not prevent the change in attractiveness due to mating. The ejaculate and ovarian activation are suggested as causal factors in these processes.

Age Factors↗