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Biomedical subjects

R Cohen

Publications and source records attributed to R Cohen.

At least 541 records · Page 30Linked to original sources
PubMed1981

The Bristol Social Adjustment Guide: comparison between the offspring of alcoholic and non-alcoholic mothers.

A German translation of the BSAG was completed by class-teachers of children whose mothers had a history of alcoholism. These children were judged as showing significantly more over-reactive behaviour in school than a control group of children whose mothers had no previous alcohol abuse. Furthermore, the alcoholic mothers also reported more over-active behaviour in their own childhood. The results are supportive of retrospective studies with adult alcoholics which indicate that childhood hyperactivity may be one precursor of subsequent alcohol abuse.

Adult↗
PubMed1981

The correction of Hunter fibroblasts by exogenous iduronate sulfate sulfatase: biochemical and ultrastructural studies.

The exogenous addition of iduronate sulfate sulfatase to cultured fibroblasts of Hunter patients resulted in a full correction of the metabolic defect as demonstrated by chemical and ultrastructural analyses. As little as 25% of the normal fibroblasts' enzyme levels were sufficient for this correction. The half-disappearance time of the internalized enzyme was 3-4 days. Prolonged incubation of corrected cells resulted in a gradual reaccumulation of mucopolysaccharides.

Cells, Cultured↗
PubMed1981

The effect of barriers on spatial representations.

48 first graders and 48 fifth graders learned the arrangement of 6 objects in a novel environment containing 2 large barriers. 3 nonoverlapping paths, each connecting all locations, were devised. Children were assigned to 4 experimental conditions representing the factorial combination of number of trials of walking (2 vs. 3) and path experience (same vs. different). Those in the same path-experience group walked the same path over trials, while those in the different path-experience group walked a different path on each trial. Following these walking experiences, the children used markers to reconstruct the environmental configuration from memory. Based on the interpoint distances calculated from these placements, the presence of barriers led to overestimations of distance only for those children who received less experience, which was distributed across a variety of paths (different path experience/2-trials group). These overestimations occurred primarily for barrier-present interpoint distances viewed but not directly walked. These results are discussed in terms of the opportunities for coordinating and integrating spatial perspectives provided by these environmental experiences.

Child↗
PubMed1981

Chemically sensitive field-effect transistor to detect organophosphorous compounds and pesticides.

A critical assessment is made concerning the application of a chemically sensitive field-effect transistor (CHEMFET) to detect organophosphorous compounds and pesticides in the ambient environment at the ppb concentration level. A performance analysis of the four types of CHEMFET structures -- enzyme-coupled, galvanostatic, catalytic, and work-function -- is presented. The integration of chemically sensitive polymers with the field-effect transistor structure is addressed. The focus of the assessment deals with practical performance criteria such as sensitivity, response time, reversibility, shelf-life, operational life, and lifetime.

Catalysis↗
PubMed1980

[Influence of mnemonic, semantic, and conceptual factors on the performance of aphasic patients in the Token Test (author's transl)].

Three experimental modifications of the Token Test were presented to 40 aphasics with predominantly expressive disturbances and 40 control patients with diffuse brain damage. On each token a human figure was drawn (a man, woman, boy, or girl); the size, color, and form of the token were given in the instructions, or the depicted figure was given as the target either in addition to or instead of the size and form. The mere fact that a figure was depicted on the tokens did not affect the performance of the patients. However, when the figures were mentioned in the instructions, the aphasics' performance improved significantly, although it never reached the level of the controls. An analysis of the error types suggested that the poor performance of the aphasics in the Token Test is at least in part due to difficulties identifying complex stimuli when the features are separately named in the instructions.

Aphasia↗
PubMed1980

Loudness judgments, evoked potentials, and reaction time to acoustic stimuli early and late in the cardiac cycle in chronic schizophrenics.

Two experiments were performed to test Broen's (1968) theory that chronic schizophrenics show increased sensitivity of the inhibitory mechanisms assumed to follow cardiovascular baroreceptor stimulation. Subjects were chronic schizophrenics and normals matched for age and education. In Experiment I reaction times, vertex potentials, and loudness judgments to single tones presented during systole or diastole were analyzed. Contrary to expectation, schizophrenics more often judged tones presented during systole to be louder than tones presented during diastole; the opposite was true for normals. A similar pattern was found in Experiment II, where pairs of tones were presented instead of single tones. No influence of cardiac cycle on reacion time or evoked potentials emerged. Results do not support Broen's assumption.

Acoustic Stimulation↗
PubMed1980

Microsurgical reversal of female sterilization: the role of tubal length.

A group of 25 women who had undergone tubal sterilization by a variety of techniques underwent microsurgical reanastomosis. The length of tube remaining and the segments of tube involved were carefully noted preoperatively, but were not used as a basis for selection of patients. The only criterion utilized for selecting patients was the presence of fimbriae on at least one side. In all patients, anatomical patency was achieved at surgery. Normal intrauterine pregnancy was directly related to tubal length. Of seven patients who had less than 3 cm of tube, none achieved pregnancy. Of seven patients who had 3 to 4 cm of tube, three achieved a normal intrauterine pregnancy. Among 11 patients who had over 4 cm of tube, all 11 achieved a normal intrauterine pregnancy. No significant difference in pregnancy rate was noted in women who had short segmants of ampulla so long as total tubal length was adequate.

Fallopian Tubes↗
PubMed1980

Laparoscopy for cryptorchidism.

Laparoscopy is suggested as an accurate way to localize the non-palpable testicle or to diagnose anorchia without an abdominal exploration. From our early experience laparoscopy will aid greatly in the management of the intra-abdominal testicle.

Adult↗
PubMed1980

Substrate-induced dissociation of glycerol-3-phosphate dehydrogenase and its complex formation with fructose-bisphosphate aldolase.

A threefold decrease in specific activity of glycerol-3-phosphate dehydrogenase was found on going from 800 nM to 10 nM enzyme concentration. According to ultracentrifugal analyses the dimeric glycerol-3-phosphate dehydrogenase (molecular weight 78,000) dissociates into monomers in the equilibrium mixture of its substrates and products. The concentration-dependent decrease in the specific activity is interpreted as a consequence of subunit dissociation and the estimated dissociation constants are 0.7 micro M and 3.5 micro M at 38 degrees C and 20 degrees C respectively. According to active-enzyme-band centrifugation experiments and kinetic analysis aldolase forms a complex with glycerol-3-phosphate dehydrogenase and this complex formation influences the specific activity of the dehydrogenase. The interaction between glycerol-3-phosphate dehydrogenase and aldolase can provide a regulatory mechanism at the branching point of glycolytic and lipid metabolic pathways.

Animals↗
PubMed1980

Studies of orthotopic allografts of oral mucosa and skin across a histocompatibility barrier in a model system.

The mucosal allograft offers a reproducibile model for the characterization of the response of the oral mucosa to immunopathologic processes. Orthotopic allografts of oral mucosa or of skin were exchanged between pairs of unrelated rabbits known to be either matched or mismatched at the major histocompatibility locus (RLA). Rabbits with autografts of these tissues served as controls. The behavior of allografts of oral mucosa and of skin, although similar in many ways, showed marked differences in the morphology of the rejection reaction including more striking vascular damage and vascular occlusion in skin and in the longer persistence of granulocytes throughout the period of rejection in mucosal allografts. The rejection of matched allografts appeared morphologically similar to that of mismatched grafts but the time sequence was delayed. Morphological differences between the rejection reactions in allografts or oral mucosa and those of skin may result from differences in the expression of histocompatibility and tissue specific antigens in these tissues as well as other local factors such as the nature and distribution of mucosubstances of the connective tissue ground substance, the regional blood flow, and the absorption of salivary components including water in an oral wound.

Animals↗