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Biomedical subjects

R Chase

Publications and source records attributed to R Chase.

At least 73 records · Page 4Linked to original sources
PubMed1976

4S oop RNA is a leader sequence for the immunity-establishment transcription in coliphage lambda.

oop RNA, which is initiated at the po promoter and is 81 nucleotides long, can function as a leader sequence for the lambda immunity establishment transcription, previously believed to originate at a special promoter pre located in the y region. Thus, oop RNA seems to have a dual role, either favouring the lytic cycle as a primer for the initiation of lambda DNA replication, or leading to the establishment of lysogeny when elongated into the imm transcript, which directs synthesis of the repressor.

Coliphages↗
PubMed1976

Insulin resistance and acanthosis nigricans. Report of a case with antibodies to insulin receptors.

A 64-year-old black man presented with the syndrome of acanthosis nigricans and insulin-resistant diabetes mellitus requiring up to 3000 units of insulin per day. The patient's plasma contained circulating antibodies to insulin receptors thought to be responsible for the insulin resistance. The marked insulin resistance, the manifestations of acanthosis nigricans, the evidence of immunologic dysfunction by the absence of expected circulating antibodies to insulin, and the demonstration of circulating antibodies to insulin receptors put this patient in Kahn's category B of insulin resistance and acanthosis nigricans. There was no evidence of malignancy, lipodystrophy, or endocrine abnormality. The occurrence of acanthosis nigricans with insulin resistance due to binding of cell membrane insulin receptors by antibodies has been reported exclusively in women. This case report is the first description of a male patient with the syndrome of insulin resistance and acanthosis nigricans and focuses attention on features that might mislead one to suspect other causes of insulin resistance.

Acanthosis Nigricans↗
PubMed1975

Cardiobacterium hominis endocarditis with cerebral mycotic aneurysm.

Cardiobacterium hominis, a recently recognized Gram-negative pathogen, was recovered in blood cultures from a 65-year-old man with indolent endocarditis of previously normal heart valves. Despite the low virulence of the organism, major cardiac damage required valvular replacement, and there were multiple cerebral emboli with development of a mycotic aneurysm. After bacteriological cure, he died of a ruptured aneurysm.

Aneurysm, Infected↗
PubMed1975

The effects of delta9-tetrahydrocannabinol on action potentials in the mollusc Aplysia.

The effects of delta9-tetrahydrocannabinol (delta9-THC) on action potentials were examined during intrasomatic recordings from the isolated buccal and parieto-visceral ganglia of Aplysia californica. When added to the saline solution bathing the preparation, the compound (in concentrations 10(-4) - 10(-5) M) caused a reduction in spike overshoot (15-20% of total amplitude) and increased the lability of responses to electrical stimulation. The somatic membrane appeared to be more affected than the axonal membrane. Diffusion barriers in the ganglion probably account for the high degree of variability in drug response, such that both of the characteristic changes were observed in only about 30% of the tests. This is the first report to describe effects of delta9-THC on invertebrate neurones. The results indicate that delta9-THC causes a depression in nerve cell excitability, and these data are consistent with reported effects of THC compounds in mammals.

Action Potentials↗
PubMedDate not supplied

Interrelationships of the emotionally positive and negative regions of the brain of the edible snail.

The changes in the behavior of the garden snail during self-stimulation through electrodes chronically implanted in specific regions of the brain are described in this study. The stimulation of the mesocerebral region led to an increase in the frequency of reinforced behavior, whereas stimulation of the rostral portion of the parietal ganglia led to a decrease in the frequency of reinforced behavior. An inference is reached regarding the emotional coloration of the effects of the stimulation of these regions. The interrelationships of the neurons located in the mesocerebrum and the parietal ganglia were studied in neurophysiologic experiments. It was found that the activation of the cells of the mesocerebrum inhibits the spontaneous activity of the serotoninergic cells of the pedal ganglia which sensitize the defensive reactions of the snail, and simultaneosly attenuate the sensory input of the command neurons of defensive behavior, which leads to the effective inhibition of the defensive reactions that is necessary during the activation of sexual behavior.

Animals↗