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Biomedical subjects

C Smith

Publications and source records attributed to C Smith.

At least 1,027 records · Page 57Linked to original sources
PubMed1980

Prolonged increases in paradoxical sleep during and after avoidance-task acquisition.

Rats were trained in a two-way shock-avoidance task, either in a single training session of 100 trials or over a 5 day period with 20 trials per day. Electroencephalograph and electromyograph recordings were continuous for 2 days prior (base line), during, and following the experiments, except during the actual training sessions. Animals that learned the task showed marked increases in PS. Rats that learned the distributed trials training task showed PS increases in the 24 hr period prior to a maximum increase in correct performance. These PS elevations appeared after a 10 hr latency following the training session. The animals that learned the single training session exhibited PS increases that persisted for a period of 6 days, which appeared daily in a cyclic manner. The latency to onset of these PS changes was less than 1 hr. The PS increases in both types of training were due to an increase in the number of PS periods and are believed to be different manifestations of the same flexible mechanism. This mechanism is considered to be involved with some aspect of learning other than the acquisition process, such as retention.

Animals↗
PubMed1979

Oxygen consumption of rat tissue slices exposed to methylmercury in vitro.

The physiological significance of damage from methylmercury exposure was assessed by comparing the oxygen consumption of rat liver, kidney and brain tissue slices after direct exposure to methylmercury chloride. Standard Warburg respirometers were used. Methylmercury chloride was added during the preparation of the experimental flasks and the tissues were preincubated for up to one hour. Oxygen consumption was accelerated by tipping sodium succinate into the main chamber from the sidearm. During the ensuing 3 h of observation, oxygen was consumed at a uniform rate and all the organ slices were equally inhibited at the respective concentrations of methyl-mercury tested. Brain slices without excess succinate were slightly more sensitive to the presence of methylmercury, but this difference was significant only at 2 . 10(-4) M methylmercury. The results suggest (a) that all three organs are about equally sensitive to direct toxic insult by methylmercury under standardized conditions, (b) that any difference observed is due to metabolic reserve capacity and (c) that organ damage induced by methylmercury cannot be attributed to a direct interference with the glycolytic machinery of the cells since organ tissue levels at the point of intoxication are considerably lower.

Animals↗
PubMed1979

Search for viral nucleic sequences in rheumatoid cells.

DNA and RNA were extracted from synovial membranes, synovial fibroblast cells, peripheral blood lymphocytes, and synovial fibroblast cells strains derived from patients with rheumatoid arthritis and other joint conditions. They were hybridised after immobilisation on nitrocellulose filters with iodinated viral nucleic acids extracted from measles, rubella virus, SV--40, and a retrovirus, RD--114. In addition, in situ-hybridisation was carried out on sections of synovial membranes by means of iodinated measles and rubella virus RNA. In no case did any hybridisation occur. Positive control systems included synovial fibroblast strains transformed with SV--40, LLC--MK2 cells chronically infected with rubella virus and RD cells infected with RD--114. It was concluded tht the synovial cells did not contain viral genomes of measles, rubella virus, SV--40, or RD--114, or at least at a level equivalent to the positive control cells.

Arthritis, Rheumatoid↗
PubMed1978

Carcinoma in situ.

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Carcinoma in Situ↗
PubMed1978

On effects of relaxed selection in familial disorders.

Theoretical predictions are made of the effect of improved treatments, with consequent increase in fertility of affected individuals, on the frequency of familial disorders. Multifactorial inheritance and some two-locus models are considered. (Changes for simple Mendelian disorders have been estimated previously by many authors.) It is estimated that, with two-locus or multifactorial models, an increase in frequency per generation of not more than a few per cent of the frequency of a disorder may be expected. The greatest increase will be in the first generation following introduction of the new treatment.

Gene Frequency↗
PubMed1978

Immunological distinction between neurofilament and glial fibrillary acidic proteins by mouse antisera and their immunohistological characterization.

Antisera were raised in mice to the presumed protein subunits of the two types of 100 A filaments in nervous tissue, glial fibrillary acidic (GFA) protein and neurofilament (NF) protein. These antisera detect a pronounced antigenic distinction between these two proteins. Antiserum to GFA protein reacts only with astroglial cells and is therefore similar to antisera prepared in rabbits. Mouse antiserum to NF protein reacts with neurons and their processes known to be rich in 100 A filaments. Postsynaptic densities do not detectably react with anti-NF antiserum when assayed by the indirect immunoperoxidase method and studied at the electron microscopic level. The two antisera do not react with actin, myosin oe nervous system, NF protein is immunohistologically detectable at embryonic day 13 (the earliest stage tested). GFA protein is not detectable with this method during embryonal development but becomes apparent only at early postnatal ages. In several species (rabbit, rat, chicken, fish, turtle, and frog) anti-NF protein antiserum only reacts with neurons, and anti-GFA protein antiserum stains glia exclusively. On the surface of trypsin-dissociated, single liver cerebellar cells from 7-day-old mice, each antiserum detects antigenic specificities which are cross-reactive with its corresponding antigen.

Animals↗
PubMed1978

Roentgenologic appearance of fibromuscular dysplasia.

Clinical and roentgenologic findings in 100 hypertensive patients with fibromuscular disease of the renal arteries are presented and compared with the experiences obtained from previously reported large series. Frequency of bilateral disease and abnormal findings at urography, involvement of segmental arteries and occurrence of extrarenal manifestations are reported. A striking female preponderance is noted, and there is evidence that the disease inflicts middle-aged rather than young women.

Adolescent↗
PubMed1978

Arterial blood gases in Pranayama practice.

Pranayama is a Yogic breathing practice which is known experientially to produce a profound calming effect on the mind. In an experiment designed to determine whether the mental effects of this practice were accompanied by changes in the arterial blood gases, arterial blood was drawn from 10 trained individuals prior to and immediately after Pranayama practice. No significance changes in arterial blood gases were noted after Pranayama. A neural mechanism for the mental effects of this practice is proposed.

Adult↗