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Biomedical subjects

I Nachshon

Publications and source records attributed to I Nachshon.

At least 19 recordsLinked to original sources
PubMed1987

Birth stress and lateral preferences.

Conflicting evidence exists concerning the possible role of birth stress in the etiology of left-sided lateral preferences. In order to clarify this issue, associations among lateral preferences of hand, eye, and foot and eight indices of prenatal and perinatal stress were examined in the present study on a sample of 987 boys and girls who participated in the Philadelphia Collaborative Perinatal Project. Controls were instituted for some of the methodological and measurement problems encountered in past birth stress and laterality research. Results showed that subjects with different lateral preferences did not differ significantly in their distributions of all but one birth stress items. Hence, there was no substantial evidence for a link between birth stress and left-sided preferences. Alternative hypotheses for the etiology of left-sidedness should therefore be explored.

Apgar Score↗
PubMed1987

Effect of lithium carbonate on lateralized cognitive functions.

The effect of lithium carbonate on lateralized cognitive functions was studied by asking a patient suffering from a manic-depressive disorder to repeatedly recognize a given series of digits delivered dichotically while varying the dosage of lithium carbonate intake. The data showed that, whereas digit recognition from the right ear (left hemisphere) was about the same across tests, recognition from the left ear (right hemisphere) varied systematically with dosage variations. Specifically, it was found that an increase in dosage of lithium carbonate was associated with a decrease in recognition from the left ear. These data might indicate unilateral hemispheric effects of lithium carbonate on the dysfunctional right hemisphere of patients suffering from bipolar affective disorders. Clinical implications of the findings of the present case study are also discussed.

Adult↗
PubMed1986

Protease inhibitor activity in human skeletal muscle.

Myofibrillar protease activity and activity of inhibitors toward trypsin, chymotrypsin, elastase, and the myofibrillar protease were determined in human skeletal muscle. The protease activity was found to increase in patients with acute and chronic inflammation as well as in patients with metastatic and nonmetastatic tumors. The inhibitory activity directed against trypsin and chymotrypsin was not affected by acute inflammation, while the inhibition of elastase and the myofibrillar protease was increased. Chronic inflammation did not affect the ability of the muscle cytosol to inhibit trypsin and elastase, but increased the inhibition of chymotrypsin and the myofibrillar protease. Nonmetastatic tumors produced an increase in the activity of inhibitors toward trypsin, chymotrypsin, and elastase, while patients bearing metastatic tumors had a high level of cytosolic inhibitors of all the tested proteolytic activities. These results indicate that the myofibrillar protease and the cytosolic protease inhibitors in human skeletal muscle are differentially affected by catabolic conditions.

Abdominal Muscles↗
PubMed1986

Birth order and lateral preferences.

Associations between birth order and lateral preferences of hand, eye and foot were examined in a sample of 6436 black seven year old boys and girls whose mothers participated in the Collaborative Perinatal Project (CPP) in Philadelphia. Overall, most of the subjects (87%) showed right hand preference, and the majority of subjects showed right eye (55%) and foot (63%) preferences. Analysis of cross preferences indicated some tendency for a consistent right side orientation. However, patterns of lateral preferences were similar for both boys and girls across seven birth order groups. The data were interpreted as showing that birth order and lateral preferences are not interrelated.

Black or African American↗
PubMed1986

Cross-cultural differences in laterality.

Twenty Hebrew speaking subjects identified sets of six digits paired with environmental sounds. Comparison of their performance with those of Japanese- and English-speakers (Hatta & Dimond, 1981) showed that while there were no group differences in overall level of performance, right ear superiority effects were larger for the English- than for the Hebrew- and Japanese-speakers. The data can be interpreted as reflecting the effects of either the linguistic properties of the native language, or of the sequence of language acquisition.

Cross-Cultural Comparison↗
PubMed1986

Functional assay of plasminogen activator by hydrolysis of 14C-globin.

A functional method for estimation of plasminogen activator (PA) activity is described. The end-point method follows the PA-dependent conversion of the inactive plasminogen to the potent protease plasmin. The formation of plasmin is monitored by its activity on 14C-globin to form acid-soluble radioactive products. The globinolytic assay of PA shows sensitivity similar to that of the 125I-fibrinolytic assay, and is superior in sensitivity to both the chromogenic (Pyro-Glu-Gly-Arg-pNA, S-2444) and the fluorimetric (Glu-Gly-Arg-methylcoumarin amide) methods. The assay is applicable for estimation of tissue type and urokinaselike PA activity in biologic samples, including viable cells in suspension and conditioned medium.

Cell Line↗
PubMed1985

Directional preferences in perception of visual stimuli.

The present paper reviews a series of studies regarding the effects of hemispheric asymmetry and reading and writing habits on directional preferences in reproducing horizontally-displayed visual stimuli. Hebrew readers, English readers, and Arabic readers were presented with arrays of horizontally-displayed directional and nondirectional stimuli, as well as with single stimuli. They were asked to reproduce the stimuli, and the direction of their reproduction, left-right or right-left, was recorded for analysis. Generally, in reproducing arrays of stimuli, English readers showed left-right directionality, whereas Hebrew readers showed right-left directionality. But in reproducing arrays of English and Hebrew letters, subjects of both groups showed left-right and right-left preferences, respectively. However, the right-left directional preferences shown by Hebrew readers were weaker than the left-right preferences shown by English readers. It was hypothesized that these differences are due to differential reading and writing habits acquired in school by English- and Hebrew-readers. In support of the reading and writing habit hypothesis, it was subsequently found that: (a) Arabic readers, who have stronger right-left reading and writing habits than Hebrew readers, show relatively stronger right-left directional preferences, and (b) with the introduction of English as a foreign language in the fifth grade, children show an increase in left-right directionality. Further investigation showed that, depending on the experimental conditions, directional preferences may be a function of either reading and writing habits, or hemispheric asymmetry, or both. Finally, the bearing of these findings on the "nature-nurture" controversy regarding the development of perceptual exploration in children is discussed.

Dominance, Cerebral↗
PubMed1984

Plasminogen activator activity in differentiating leukemia cells.

Plasminogen activator (PA) activity of human promyelocytic leukemia cell line HL-60 was assayed by following the conversion of plasminogen to plasmin and the plasmin-mediated hydrolysis of 14C-labeled globin. When HL-60 cells were induced to differentiate into macrophages by 12-O-tetradecanoyl-phorbol-13-acetate (TPA), cell-associated PA activity and secretion of PA into the conditioned medium increased profoundly. PA activity increased earlier and as a result of lower concentrations of TPA than the ability of the cells to adhere. Exposure to 10(-6)M dexamethasone did not prevent TPA-induced adherence and produced a slight inhibition of cellular PA activity. These findings imply that TPA-induced differentiation of HL-60 cells to macrophage-like cells is associated with induction of PA activity.

Cell Adhesion↗
PubMed1983

Phorbol ester-induced adhesion of murine erythroleukemia cells: possible involvement of cellular proteases.

Phorbol ester tumor promoters produce a rapid increase in adhesiveness of murine erythroleukemia (MEL) cells. Following treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and other tumor promoters, these cells adhere to the surface of the culture dish or become agglutinated to each other. Structurally related compounds which are devoid of tumor promoting activity failed to induce agglutination of MEL cells. Pentamidine isethionate (PI) and tosylamide-phenylethyl-chloromethyl ketone, two known inhibitors of trypsin-like enzymes, prevent the phorbol esters-induced adherence and agglutination. A short exposure to TPA results in an increase in protease activity at the alkaline pH range. This TPA-induced proteolytic activity is inhibited by PI. Induction of erythroid differentiation by hexamethylene-bisacetamide is associated with a decrease in TPA-induced cell adhesion and TPA-induced proteolytic activity. Taken together, these results suggest the participation of an alkaline proteolytic activity in the membranal changes evoked by phorbol esters.

Animals↗
PubMed1983

Directional preferences of bilingual children.

Effects of simultaneous acquisition of differential reading and writing habits (in English and Hebrew) on directional preferences were investigated for 72 bilingual children in Grades 1 to 6. The children reproduced series of single and multiple stimuli; horizontal directions of their responses were recorded. Increased age was accompanied by growing left-right directional preferences in response to all stimuli but Hebrew letters, for which the reversed right-left preferences appeared. These data corroborate previous findings showing effects of reading and writing habits on directional preferences.

Child↗
PubMed1983

Lateral preferences of hand, eye and foot: relation to cerebral dominance.

Patterns of lateral preferences of hand, eye and foot were analyzed on 7364 children, differing in race (black and white) and sex. Right hand and foot preferences were found in over 80%, and right eye preferences were found in over 50% of the subjects. No sex or race differences appeared in left-right preferences. However, significantly more females than males, and more blacks than whites, showed variable foot preference. Further analyses of cross preferences indicated that about 40% of the subjects showed consistent lateral preferences of hand, eye, and foot (about 37% right, and about 3% left), whereas the other 60% were divided among ten groups of different preference combinations. The three lateral measures were correlated to differing degrees. The data were interpreted as showing the effects of cerebral dominance on lateral preferences of hand, eye and foot. The effects seemed to be considerably stronger for hand and foot than for eye preferences. Due to a lack of supporting data, interpretation of race differences in variable foot preference must be considered tentative.

Black or African American↗
PubMed1983

Asymmetry in lateral directionality.

Effects of laterality and reading habits on directional preferences were investigated in two experiments. The subjects (N = 40 and 33 in Experiments I and II respectively) were right-and left-handed, male and female Israelis, whose native tongue was Hebrew. They identified and reproduced horizontal arrays of visual stimuli, which were presented either simultaneously (Experiment I), or sequentially (Experiment II). Directional preferences of the subjects' responses were recorded and analyzed. In Experiment I subjects of all groups showed similar, left-right directional preferences. In Experiment II right handers showed right-left preferences, whereas left handers showed inconsistent response patterns. Sex differences appeared among left handers only. The results were interpreted as showing the predominance of reading habit effects in Experiment I, and of laterality effects in Experiment II. It was therefore concluded that, depending on the experimental conditions, directional preferences may be a function of either reading habits, or laterality, or both.

Analysis of Variance↗
PubMed1982

Early cognitive functioning: sex and race differences.

Six scales of early cognitive functioning were administered at three times (eight months, four and seven years) to 3013 black and white, male and female children. Hypotheses addressed the nature and extent of longitudinal sex differences in cognitive abilities among racial groups varying in physical maturation. Controlling for selected socioeconomic influences, a slight sex by race interaction was found at four and seven years. Generally, white females scored somewhat lower on cognitive tests than white males, whereas black females scored equivalently or somewhat higher than black males. Test score differences among the four sex and race groups were more apparent in seven-year spatial abilities relative to verbal abilities. Findings are discussed in terms of possible maturational and environmental influences on cognitive abilities among different sex and race groups.

Child↗
PubMed1980

Hemispheric dysfunctioning in schizophrenia.

Reinterpretation of old data (J. Nerv. Ment. Dis., 164:247-252, 1977), which showed greater right ear superiority effects for schizophrenic patients than for normal controls in dichotic listening, lends support to the assumption of left hemisphere overactivation among schizophrenics. This overactivation seems to be more pronounced among paranoid than among nonparanoid schizophrenics.

Auditory Perception↗
PubMed1980

Localization of cholinesterase in Pseudomonas aeruginosa strain K.

The inducible cholinesterase of Pseudomonas aeruginosa strain K (ATCC 25102) degraded propionylcholine, acetylthiocholine, acetylcholine and acetyl-beta-methylcholine at a high rate and butyrylcholine and succinylcholine at very low rates. The localization of the enzyme in the periplasmic space was indicated by a similar rate of acetylcholine degradation by intact cells or their extracts, by release of cholinesterase together with alkaline phosphatase into the culture medium during cell growth in a low phosphate-containing medium, by liberation of cholinesterase and alkaline phosphatase during lysozyme-induced conversion of cells to spheroplasts and by freezing and thawing. Threatment of cells with diazo-7-amino-1,3-naphthalenedisulphonic acid, which inactivates surface-located enzymes, abolished most of the cholinesterase and 5'-nucleotidase activities.

Alkaline Phosphatase↗
PubMed1978

Handedness and dichotic listening to nonverbal features of speech.

The assumption that pitch and loudness are processed in the right hemisphere was tested by comparing left-handers' with right-handers' performance on pitch and loudness discrimination tasks. Four groups of left-handers (20 subjects in each group) were dichotically presented either with digits varying in pitch or loudness or with pure tones varying in pitch. The subjects identified the digits, or the pitch and loudness variations, from both ears. Confirming the assumption, the data showed that the left-handers, who had no ear preference on any of these tasks, differed significantly from the right-handers, who, preferring the right ear for digit identification, preferred the left ear for the discrimination of the nonverbal features (pitch and loudness) of these digits.

Functional Laterality↗
PubMed1977

Responses of paranoid and nonparanoid schizophrenics in a dichotic listening task.

Differences in attentional processes between normals, paranoid schizophrenics, and nonparanoid schizophrenics were studied by delivering dichotically presented digits for identification. Thirty paranoid schizophrenics (20 acute and 10 chronic), 30 nonparanoid schizophrenics (20 acute and 10 chronic), and 20 normal controls were tested. The data were analyzed in terms of the overall level of correct identification of stimuli presented to the two ears, the number of shifts in report from one ear to the other, and the magnitude of ear differences in recall. The results showed that overall level of performance was higher for the normals than for the schizophrenics; the number of ear shifts was greater for normals and nonparanoid than for paranoid schizophrenics; and ear differences were biggest for the paranoid schizophrenics and smallest for the normals. The results were interpreted in terms of differences in attentional style and rate of information processing.

Adolescent↗