Biomedical subjects
R Swenson
Publications and source records attributed to R Swenson.
Reducing response time in potential MI cases.
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Crossed aphasia in early childhood.
A four-year-old child was admitted to hospital with an infarct of the right middle cerebral artery involving the frontoparietal area. His symptoms included left hemiplegia and aphasia. After two weeks, he had hemiparesis, word-finding and naming problems and enuresis. A year later he demonstrated elective mutism at school, had attention and short-term memory impairments, occasional enuresis and an average IQ. He was shy and withdrawn; this is interesting, since depression is usually associated with left-hemispheric lesions. It is suggested that an early period of mutism should be included among the criteria for the study of crossed aphasia in children, as this is a common occurrence in such cases. Even after recovery of speech, impairments in attention and academic skills may persist.
A seasonal pineal peptide rhythm persists in superior cervical ganglionectomized rats.
Neurohypophyseal peptide hormone activity is present in the pineal gland of mammals, and varies over a seasonal cycle. Pineal peptide levels, measured by arginine vasotocin (AVT) radioimmunoassay, increase dramatically for a brief time during August each year. The manner in which this cycle is regulated is as yet unknown. Input to the pineal from sympathetic axons arising in the superior cervical ganglia (SCG) is essential for the generation and regulation of the circadian rhythm in melatonin synthesis, and is the only pathway known to regulate pineal biochemical processes. It was of interest then to determine the impact of the SCG on the seasonal peptide cycle. Levels of pineal arginine vasotocin immunoactivity (iAVT) were monitored during August, 1984, in rats which had been superior cervical ganglionectomized (SCGX), in sham-operated and intact controls (L:D 12:12), and in rats subjected to L:D 22:2. The results indicate that SCGX does not abolish the seasonal cycle, but may influence the timing of the iAVT peak. Inhibition of pineal melatonin synthesis by exposure of rats to L:D 22:2 did not mimic the phase delay seen with SCGX, but did cause a significant increase in the amplitude of the August iAVT activity peak.
Phenotypic characterization of Neisseria gonorrhoeae isolated from three cases of meningitis.
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Ebstein's disease associated with complete atrioventricular block.
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Nuclear morphometry during the cell cycle.
Directly measured and derived geometric and densitometric parameters were obtained by means of the automated image analyzer Quantimet 720-D in Feulgen-stained HeLa cells synchronized by selective mitotic detachment. These data indicate substantial alteration of nuclear morphology during the entire cell cycle, even during the G1 and G2 phases, and the late G1-early S and late S-G2 transitions.
Letter: Electrolyte disturbances in beer drinkers.
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Cardiac arrest due to oral potassium administration.
Cardiac arrest developed in two patients after the administration of oral potassium. Neither patient had renal insufficiency, but both had underlying heart disease. In one patient fatal ventricular fibrillation developed 4 days after he received an aortic valve replacement for aortic stenosis and while he was receiving oral potassium supplements. The serum potassium level before cardiac arrest was 8.1 meq. The second patient had angina and was given 40 meq of potassium orally 15 minutes after an exercise test which produced chest pain and S-T segment depression. One hour later, ventricular fibrillation developed. Resuscitation was successful. Both patients had electrocardiographic evidence of hyperkalemia. Oral administration of potassium may produce severe cardiac toxicity in patients with heart disease even when renal function is clinically normal.
Binswanger's disease: some neuropsychological considerations.
The literature regarding Binswanger's disease is reviewed. Emphasis is placed on reviewing the neuropsychological literature related to Binswanger's disease. In addition, a retrospective analysis was carried out among four groups of subjects (N = 61) who were divided according to the presence or absence of dementia and deep white-matter alterations. A main effect for deep white-matter alterations was found for almost all measures of diastolic and systolic blood pressure. Among the two nondemented groups there was an effect of deep white matter alteration on neuropsychological functioning. Subjects with deep white matter changes performed worse on tests of immediate and delayed recall of a prose passage. Among the two demented groups there were no differences on any of the neuropsychological measures, although subjects with deep white matter alterations exhibited a higher incidence of focal neurologic signs and stroke. We conclude that Binswanger's disease is probably more prevalent than currently appreciated. Also, among clinically nondemented individuals periventricular white-matter alterations may be associated with subtle but definable neuropsychological deficits, and these individuals may be at risk for developing a dementing illness.
Changes in chromatin morphology after infection of mouse embryo fibroblasts with polyoma virus, detected by image analysis.
Nuclear chromatin properties in control, SV40-infected and polyoma-infected cultures of mouse embryo fibroblasts were studied using quantitative image analysis. Distribution of Feulgen-DNA-content per nucleus was found to be similar in all three groups of cultures. No differences in nuclear area, mean optical density of chromatin and area of chromatin at different optical density thresholds were measurable between control and SV40-infected fibroblasts. Polyoma-infected fibroblasts were found to have smaller nuclei, more dense and less homogeneous chromatin than non-infected cells. The changes of chromatin in polyoma-infected cells occur in G1, middle S and G2 nuclei. The results are interpreted as an early manifestation of the cytopathic effect of polyoma virus.
Image analysis of nuclei of cultured fibroblasts obtained from human uterine cervix with various lesions.
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