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Biomedical subjects

R W Beck

Publications and source records attributed to R W Beck.

124 records · Page 7Linked to original sources
PubMed1979

The effect of ribonuclease on the replicative forms of Sindbis virus RNA.

Three species of double-stranded RNA, designated RF I, RF II, and RF III in order of decreasing size (25), are produced by ribonuclease treatment of extracts of chicken embryo cells infected for 6 hours with Sindbis virus. Only one class of replicative form RNA is present in extracts not treated with ribonuclease; this class contains some molecules which can be enzymatically cleaved to produce the other two replicative forms. At a low level of enzyme (0.001 microgram/ml) the major species obtained was RF I, the replicative form of the genome. When the enzyme concentration was increased 10-, 100-, and 1000-fold, there was a progressive increase in the proportions of RF's II and III and a concomitant decrease in the proportion of RF I. The generation of RF's II and III by nuclease resulted in the ratio expected for these two species if they are produced by cleavage of RF I-like molecules. In preparations of isolated double-stranded RNA, only RF I and replicative intermediate RNA were present. Mild nuclease treatment of these preparations converted the replicative intermediates primarily to RF I. Higher enzyme levels generated greater proportions of RF II and RF III, but RF I-like molecules were the major source for these increased proportions. Treatment of the isolated naturally occurring replicative form with 0.01 microgram of ribonuclease per ml cleaved some molecules migrating as RF I during gel electrophoresis into molecules which migrated as RF II and RF III.

Animals↗
PubMed1977

The effect of alcohol and smoking on testosterone function and aggression in chronic alcoholics.

Forty alcoholics without other significant medical or psychiatric problems were studied on a research ward for two weeks. All subjects abstained from alcohol and cigarettes during the first week; 30 randomly selected subjects were permitted unlimited alcohol and/or cigarettes during the second week. Plasma testosterone levels were normal during the first week but decreased rapidly and significantly in those subjects allowed alcohol. A variety of measures of affect failed to show a significant correlation between hostility/aggression and plasma testosterone levels or alcohol ingestion.

Adult↗
PubMed1971

Properties of aldolase from Francisella tularensis.

The aldolase of Francisella tularensis resembles Class II aldolases in its requirement for divalent ions and its inactivation by metal chelating agents. Cysteine and other reducing agents stimulated the activity of the enzyme.

Chelating Agents↗
PubMed1968

Activities of arginine dihydrolase and phosphatase in Streptococcus faecalis and Streptococcus faecium.

Strains of Streptococcus faecalis and S. faecium are known to produce ammonia from arginine, but only S. faecalis couples the adenosine triphosphate (ATP) produced through the arginine dihydrolase pathway to growth processes. The specific activities of the arginine dihydrolase enzymes were found to be much lower in S. faecium (0.01 to 0.10) than in S. faecalis (0.24 to 1.60). Phosphatase activities in both strains were similar (up to 0.11), but equaled or exceeded the activities of the arginine dihydrolase enzymes in S. faecium. The failure of S. faecium to show increased growth in arginine media is explained on the basis of low activities of the arginine dihydrolase enzymes coupled with sufficient phosphatase activity to negate any benefit from ATP formed.

Adenosine Triphosphatases↗
PubMed1966

Occurrence and Distribution of Proteinase of Streptococcus faecalis var. liquefaciens.

Shugart, Lee R. (University of Tennessee, Knoxville), and Raymond W. Beck. Occurrence and distribution of proteinase of Streptococcus faecalis var. liquefaciens. J. Bacteriol. 92:338-341. 1966.-The proteolytic enzyme produced by Streptococcus faecalis var. liquefaciens (ATCC 13398) was shown to be an exoenzyme. The production of the proteinase was followed in growing cultures, and its distribution was compared with that of the intracellular enzymes reduced nicotinamide adenine dinucleotide (NADH(2)) peroxidase and lactate dehydrogenase. The proteinase appeared in the culture medium prior to the stationary phase of growth, whereas the other enzymes could be found only in whole cells. Fractionation of whole cells by sonic treatment and by treatment with lysozyme showed the proteinase to be associated primarily with the cell wall and cell membrane, and NADH(2) peroxidase to be associated only with the cytoplasmic fractions.

Journal Article↗
PubMedDate not supplied

Retinitis pigmentosa. A mimic of neurologic disease.

Six patients with various forms of retinitis pigmentosa who were misdiagnosed as having neurologic disease are presented. In five of the patients, visual field defects were misinterpreted as being secondary to a neurologic rather than a retinal problem. In two patients, optic nerve drusen, which accompanied the retinal degeneration, were mistaken for papilledema. Since the diagnosis of retinitis pigmentosa is not always obvious on ophthalmoscopy, the clinician must be aware of the various manifestations of this disorder and be able to distinguish visual field defects on a retinal from a neurologic basis.

Adolescent↗
PubMedDate not supplied

What to tell the patient with optic neuritis about multiple sclerosis.

If the ophthalmologist tells the patient with an initial isolated attack of optic neuritis that multiple sclerosis may develop, will he/she worry the patient needlessly or provide useful information that the patient is rightfully entitled to have? In this set of articles, the philosophies and individual circumstances that should influence the ophthalmologist in deciding what information to supply are discussed.

Delivery of Health Care↗
PubMedDate not supplied

Neuroretinitis in childhood.

We report the clinical features and results of laboratory testing of seven children with neuroretinitis, diagnosed on the basis of reduced visual acuity, relative afferent pupillary defect, and distinctive appearance of the fundi. Disc swelling was segmental in five patients with unilateral disease and diffuse in two patients with bilateral disease. Retinal infiltrates were transiently present in two patients. Swelling of the optic disc and peripapillary retina, along with the inflammatory vitritis resolved by 2 to 6 weeks but macular exudates persisted for 3 to 12 months. Two patients developed optic atrophy with permanent visual loss and two patients had visual acuity reduction detected only under low contrast conditions. Cat-scratch disease was implicated as the cause of the neuroretinitis in two patients; the etiology of the remaining cases was not established.

Adolescent↗