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Biomedical subjects

L Cohen

Publications and source records attributed to L Cohen.

At least 199 records · Page 11Linked to original sources
PubMed1994

Amnesia for arithmetic facts: a single case study.

We report the case of an anarithmetic patient with a selective deficit of memory for elementary arithmetic facts, who produced, for instance, "25" in answer to "4 x 5." The patient showed good language comprehension and production abilities, had minimal number transcoding difficulties, and mastered normally multidigit arithmetic procedures. She was submitted to a series of calculation, verification, and number classification tasks. The arithmetic deficit was evident in both recognition and recall tasks, was consistent across testing sessions, and did not vary as a function of the format used for presentation of the problems. The patient failed even when only implicit access to arithmetic facts was expected: In a timed addition verification task, she did not show a normal inhibition effect when rejecting addition problems in which the proposed result was the product of the two operands (e.g., "3 + 4 = 12"). We suggest that the deficit resulted from a specific and permanent degradation of some connections and nodes in arithmetic long-term memory.

Adult↗
PubMed1994

Post-therapy change in prostate-specific antigen levels as a clinical trial endpoint in hormone-refractory prostatic cancer: a trial with 10-ethyl-deaza-aminopterin.

OBJECTIVES: Serial changes in prostate-specific antigen (PSA) correlate with disease status in all stages of prostatic cancer. For hormone-refractory disease, post-therapy declines of 50% and 80% from baseline are associated with an improved survival. This study sought to evaluate edatrexate, a synthetic antifolate, in hormone-refractory prostatic cancer using post-therapy PSA change as the initial endpoint. METHODS: Fourteen patients with progression of disease despite castrate levels of testosterone received edatrexate. Serial changes in PSA were monitored and correlated with other parameters of outcome. RESULTS: Stabilization of a rising PSA level in parallel with clinical stabilization of disease was observed in one patient; disease in all others progressed. Toxic reactions were acceptable. CONCLUSIONS: With no objective evidence for antitumor activity as assessed by post-therapy PSA changes in any of the patients treated, edatrexate seems a poor candidate for future study. The use of post-therapy PSA change as the initial screening modality allows treatments to be evaluated rapidly in patients without measurable disease. The methodology proposed will require validation in prospective phase III investigations using survival as the endpoint.

Aged↗
PubMed1994

Dissociable mechanisms of subitizing and counting: neuropsychological evidence from simultanagnosic patients.

Do people have to count to determine visual numerosity, or is there a fast "subitizing" procedure dedicated to small sets of 1-3 items? Numerosity naming time and errors were measured in 5 simultanagnosic patients who suffered from severe difficulties in serial counting. Although these patients made close to 100% errors in quantifying sets comprising more than 3 items, they were excellent at quantifying sets of 1, 2, and sometimes 3 items. Their performances in visual search tasks suggested that they suffered from a deficit of serial visual exploration, due to a fundamental inability to use spatial tags to keep track of previously explored locations. The present data suggest that the patients' preserved subitizing abilities were based not on serial processing but rather on a parallel algorithm dedicated to small numerosities. Several ways in which this parallel subitizing algorithm might function are discussed.

Adult↗
PubMed1994

Psychological stress and platelet activation: differences in platelet reactivity in healthy men during active and passive stressors.

Blood platelets have been found to play a major role in the pathogenesis of coronary artery disease. This study examined the effects of active and passive stressors on platelet function and assessed the possible effects of perceived control on platelet reactivity to stress. Heart rate, blood pressure, catecholamine levels, and platelet factor 4 (PF 4) were assessed in 55 healthy males during resting baseline (25 min), 7-min stressor/task periods, and recovery (60 min). Results showed significant increases in PF 4 during the stressor/task periods for both active and passive stressor groups. Psychological stress involving both active and passive participation had a direct effect on platelet activation.

Adolescent↗
PubMed1994

Number words and number non-words. A case of deep dyslexia extending to Arabic numerals.

Although the ability to process numerical symbols may be considered a special case of more general linguistic abilities, deficits affecting numbers and words are usually interpreted within entirely independent frameworks. We report a patient presenting typical deep dyslexia, as confirmed in a series of word and non-word reading tasks. Moreover, the main features of his deficit extended to arabic numerals. The patient was equally unable to read aloud non-words and unfamiliar numerals, whereas he performed significantly better with real words and familiar arabic numerals such as famous dates or brands of cars. Additionally, familiar numerals and words yielded qualitatively similar errors, as did unfamiliar numerals and non-words. This contrasting performance with familiar and unfamiliar numerals seems incompatible with any single-route model of number reading. It is rather consistent with the existence of two routes for number reading: a 'surface' route mapping any digit string into a word sequence according to language-specific rules; and a 'deep' semantic route functioning only with familiar items that possess a specific lexical entry. We therefore suggest that number reading is architecturally similar to word reading, although these two processes probably rest on functionally and anatomically distinct pathways.

Adult↗
PubMed1994

Selective deficit of visual size perception: two cases of hemimicropsia.

Hemimicropsia is a rare disorder of visual perception characterized by an apparent reduction of the size of objects when presented in one hemifield. We report two cases of hemimicropsia resulting from focal brain lesions. The first patient was an art teacher and could accurately depict his abnormal visual perception. He subsequently died and his brain was examined post mortem. In the second patient, micropsia was assessed by a quantified size comparison task. The size of a given object is normally perceived as constant across any spatial position. Hemimicropsia may thus be considered a limited violation of the size constancy principle. Behavioural and anatomical data are discussed in relation to the neural basis of visual object perception in humans.

Autopsy↗
PubMed1994

Serotonergic sensitivity in borderline personality disorder: preliminary findings.

Twelve patients with borderline personality disorder and 15 healthy comparison subjects were challenged with single doses of oral m-chlorophenylpiperazine (m-CPP) and placebo. Following m-CPP, the patients experienced decreased anger and fear. Seven of the 12 patients reported a "spacy," "high," depersonalized/derealized experience following m-CPP, which was confirmed by clinicians' ratings. Compared with the normal male subjects, the male patients with borderline personality disorder had higher cortisol levels and marginally blunted prolactin responses after receiving m-CPP. These results suggest serotonergic dysfunction in borderline personality disorder.

Administration, Oral↗
PubMed1994

Neurological soft signs in female trichotillomania patients, obsessive-compulsive disorder patients, and healthy control subjects.

Female trichotillomania patients, obsessive-compulsive disorder patients, and normal control subjects did not differ in total scores on a neurological soft signs battery. Further studies should determine whether the increased neurological soft signs present in obsessive-compulsive disorder and perhaps in obsessive-compulsive spectrum disorders are associated with male gender only.

Adult↗
PubMed1994

Differential effects of active and passive laboratory stressors on immune function in healthy men.

The immunomodulatory effects of acute laboratory stressors were examined by comparing active and passive stressors in a between-subjects design. Healthy male volunteers (N = 67) were recruited and randomly assigned to an active, passive, or no stressor condition. Subjects were exposed to either the Stroop and mental arithmetic tasks (active). two surgery films (passive). or two nature films (no stress). Cardiovascular reactivity, plasma catecholamines and cortisol. and self-reported distress were measured pre-task and post-task. Lymphocyte proliferation to concanavalin A (Con A). pokeweed mitogen (PWM), and phytohemagglutinin was assessed a1 baseline, after the first task, after the second task, and 30 min later. Lymphocyte proliferation lo Con A and PWM was significantly reduced in response to the stressors. Different response patterns emerged, depending on the type of stressor and the mitogen used. Changes in lymphocyte proliferation were significantly associated with cardiovascular reactivity during the tasks. Results are discussed in terms of potency of the stressors and mechanisms underlying passive versus active laboratory tasks. Implications for future research are addressed.

Journal Article↗
PubMed1994

A conceptual scheme for assessing evenhandedness and (counter) self-serving attributional biases in relation to depression.

Various hypotheses have been proposed concerning the attributional styles of depressive and nondepressive persons. Some hypotheses are compatible with others; some are mutually exclusive. In this paper we present a scheme for organizing these hypotheses. A method is offered for deciding which hypothesis best fits data from samples which are heterogeneous with regard to extent of depression. The concepts reviewed include "self-serving bias," "counter-self-serving bias," "evenhandedness," "depressive lower self-enhancement," "counter-defensive attribution," the "Abramson, et al. hypothesis" that depressed persons attribute events with bad outcomes more to internal, stable, and global causes than do nondepressed persons, and the "Seligman, et al. hypothesis" that depressed persons attribute events of good outcome less to these causes than do nondepressed persons.

Depressive Disorder↗
PubMed1994

[Palliative treatment of tetralogy of Fallot by percutaneous dilatation of the right ventricular outflow tract. 40 cases].

This study was undertaken to assess the value of percutaneous dilatation of the right ventricular outflow tract as a substitute for surgical systemic pulmonary anastomosis in varieties of tetralogy of Fallot with severe irregularity or major pulmonary arterial hypoplasia unsuitable for complete repair of first intention. Fifteen neonates aged 3 to 23 days with severe desaturation (SaO2 = 73 +/- 11%) and twenty five children aged 1.2 to 174 months with anoxic crises or severe desaturation (SaO2 = 67 +/- 15%) fulfilled these criteria. They underwent right heart catheterisation completed by an attempted pulmonary dilatation. This manoeuvre failed in 6 cases, all neonates, because it was not possible to cross the annulus or maintain the balloon in position, or because of infundibular perforation. There were complications in 5 cases, all neonates: 2 tamponades with 1 death, one dissecting aneurysms of the annulus, 1 gastroenteritis and 1 caval thrombosis. Of the 34 patients dilated, 8 were poor results, mainly in the older age group (7 cases) and 26 were successful as judged by a significant improvement in arterial saturation. However, 7 patients rapidly deteriorated due to anoxic crises (6 infants and children) or fatal secondary tamponade (1 neonate). Therefore, there remained 19 stable successful procedures, 49% of attempts, representing 56% of successful attempts and 73% of primary successes. In neonates, these proportions were respectively: 47%, 78% and 87%, and in the older children: 48%, 48% and 63%.(ABSTRACT TRUNCATED AT 250 WORDS)

Balloon Occlusion↗
PubMed1993

Effects of time, sex, ethnic origin, and area of residence on prevalence of asthma in Israeli adolescents.

OBJECTIVES: To study effects of time, sex, ethnic origin, and area of residence on prevalence of asthma in Israeli adolescents. DESIGN: Retrospective survey of asthma from computerised medical draft records of conscripts examined up to the end of 1989. SETTING: Five regional centres in Israel. SUBJECTS: 443 186 conscripts (262 836 males and 180 350 females) aged 17-18 who were born over a nine year period. MAIN OUTCOME MEASURES: Asthma determined by medical history, physical examination, and lung function tests at rest and after exercise. RESULTS: Asthma was more prevalent in males than females (26.5/1000 v 21.4/1000, relative risk 1.25 (95% confidence interval 1.19 to 1.32)). Subjects were split into three groups according to year of birth, and prevalence of asthma increased over time from 18/1000 to 24/1000 to 36/1000 (risk of asthma 0.56 (0.54 to 0.59) for first birth group relative to last birth group and 0.69 (0.66 to 0.72) for second group relative to last group). Risk of asthma was also affected by ethnic origin (highest for Western origin and lowest for north African origin, relative risk 1.63 (1.56 to 1.71)) and area of residence (highest in the central coastal region--risk of 1.24 (1.19 to 1.30) relative to the north coastal region--and lowest in inland areas--risk of 0.67 (0.64 to 0.70) relative to north coastal region). CONCLUSIONS: Prevalence of asthma in Israel is increasing and is higher in males, in people of Western origin, and in those living in the most industrialised coastal region.

Adolescent↗