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Biomedical subjects

B Cohen

Publications and source records attributed to B Cohen.

At least 415 records · Page 23Linked to original sources
PubMed1981

Saccades of hyperactive and normal boys during ocular pursuit.

Eye movements of hyperactive and normal boys were compared on a visual pursuit task in three experiments. In the first series of tests, irregular pursuit occurred more often in hyperactive than in normal boys. Hyperactive boys made more saccadic movements, their average saccades were larger, and they looked away from the pursuit path more frequently than the normal boys. In a second series of tests three years later, the differences between normal and hyperactive boys still existed. In a third set of experiments the effects of an attention task, different stimulus velocities and stimulant medication were studied in another group of control and hyperactive boys. With or without the attention task, hyperactive boys not receiving stimulant medication made more saccades than normal boys. Differences were greatest at lower target velocities and decreased at higher stimulus velocities. Differences between hyperactive and normal boys disappeared when the former received both stimulant medication and the attention task. The findings were the same in the two groups of hyperactive boys: they had more saccades superimposed on ocular pursuit than did normal boys. Differences between the groups may be related to their relative ability to attend to the target. The differences are of a magnitude that might make them useful as an adjunct for diagnosis of hyperactivity or for evaluating the effects of treatment.

Adaptation, Physiological↗
PubMed1980

Educational therapy in a community mental health center.

The existence of serious psychosocial problems in adults caused by or strongly associated with various learning and educational difficulties has not been given sufficient attention by mental health programs. This paper discusses the nature, assessment, and amelioration of these problems through an educational therapy program located in a community mental health center. Educational therapy is essential for these adults because unless their learning and educational difficulties are corrected, no amount of psychotherapy by itself will fully resolve their psychosocial problems.

Adult↗
PubMed1980

Cloning DNA sequences from influenza viral RNA segments.

DNA sequences corresponding to gene segments that code for the nonstructural protein, the matrix protein, and the hemagglutinin of influenza A virus [strain A/Udorn/72 (H3N2)] were cloned in Escherichia coli pBR 322. Initially, positive and negative cDNA strands were prepared separately by reverse transcription. The positive strands of cDNA were transcribed from genomic RNA segments by using a specific dodecamer DNA sequence as a primer; the negative strands of cDNA were transcribed from cytoplasmic viral mRNA segments by using an oligo(dT) primer. DNA duplexes corresponding in size to the virus RNA segments were then purified, inserted into the plasmid DNA, and used for transformation of E. coli. The influenza virus-specific DNA sequences isolated from recombinant plasmid molecules were characterized by mapping restriction enzyme cleavage sites. In addition, the orientation of cloned DNA was determined with reference to the 3' terminus of viral RNA.

Base Sequence↗
PubMed1980

The gingival epithelium of rodent molars with limited eruption.

We have re-examined the arrangement of epithelia surrounding molar teeth with limited eruption in the rat, mouse and hamster. Our methods permitted enamel to be retained in paraffin and glycolmethacrylate sections, so providing optimal preservation of epithelial relationships. Three basic patterns of epithelial arrangement were observed on the various aspects of molars. Non-keratinized junctional epithelium covers the interdental septum and the base of all gingival crevices even in areas of gingival recession. In all areas other than the interdental septum, a fold of keratinized gingival epithelium lies beneath the lateral aspects of junctional epithelium. The buccal and lingual aspects of interdental septa show a zone of transition between these two basic types of epithelial arrangement. In intact gingiva the junctional epithelium can be seen to extend a considerable distance on to enamel surfaces, with the result that actual gingival crevice depths are even less than previously assumed. Artefacts resulting from loss of enamel during processing are discussed in the light of previous attempts to explain epithelial arrangements in rodent gingivae.

Animals↗
PubMed1980

Natural antibodies to EBV-VCA antigens in common marmosets (Callithrix jacchus) and response after EBV inoculation.

Healthy common marmosets from two separate colonies, one in England and one in France, were found to have antibodies cross-reacting with Epstein-Barr virus structural antigens (EBV-VCA). All seropositive animals were at least 2 years old. Experimental EBV infection of marmosets of different ages led to seroconversion of inoculated weanlings. Adult animals either developed antibody for the first time or showed an increase in their existing titers. Both control and infected animals developed a progressive interstitial nephritis. The lymphocytic infiltration was more extensive, diffuse and immature in appearance in inoculated animals, but no definite evidence of lymphoproliferative disease or lymphoma was found.

Animals↗
PubMed1980

Parafoveal retinal telangiectasis. Light and electron microscopy studies.

The clinical, histopathological, and ultrastructural features of a case of parafoveal telangiectasis are reported. No telangiectasis of retinal vessels was found. Instead, there was thickening of the wall of the retinal capillaries and narrowing of the calibre of the lumen. Thickening was due to marked proliferation of basement membrane in a multilayered configuration, Cellular debris from degenerated endothelial cells and pericytes, and multimembranous lamellar lipid material were entrapped between layers of basement membrane. Extensive degeneration of pericytes was observed, and occasional areas showed degenerated endothelial cells. These changes were not restricted to the clinical-affected parafoveal area but were also seen to a lesser degree throughout the retina. The changes are interpreted as being due to primary endothelial cell degeneration and regeneration, with successive waves of basement membrane production and secondary degeneration of pericytes.

Basement Membrane↗