Search PubMed⌕ Search

Biomedical subjects

H Cohen

Publications and source records attributed to H Cohen.

At least 649 records · Page 36Linked to original sources
PubMedDate not supplied

Lack of uniformity in evaluation of endoscopic prognostic features of bleeding ulcers.

Management strategies in patients with bleeding ulcers are based on ulcer appearance. We assessed the level of agreement among endoscopists regarding the labeling of endoscopic features of bleeding ulcers and also evaluated the effect of a short teaching session on the level of agreement. Two hundred two endoscopists at the 1992 American College of Gastroenterology Postgraduate Course answered multiple-choice questions using interactive keypads. They were shown 6 slides of typical ulcer stigmata of recent hemorrhage, attended a brief teaching session, and then saw 6 different slides of comparable stigmata plus 2 additional slides. Color of stigmata was assessed in 9 slides. Information on years of endoscopic experience and numbers and types of procedures performed was also obtained. The proportion of correct answers before the teaching session increased significantly with years of experience, reaching a plateau in endoscopists who were 6 years or more beyond training. The proportion of correct answers for physicians performing no more than 5 upper gastrointestinal endoscopies per month was significantly lower than for those performing more than 5 per month: 33/56 (59%) compared with 647/891 (73%), a difference of 14% (95% CI, 0.4% to 27%; p = 0.03), but performance of a greater number of endoscopies was not associated with a further increase in the rate of correct answers. The total number of correct answers increased from 845/1181 (72%) before the teaching session to 1268/1554 (82%) afterwards, a difference of 10% (95% CI, 7% to 13%; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Education, Medical, Continuing↗
PubMedDate not supplied

The role of prosody in discourse processing.

The influence of prosody and its visual analog, punctuation, in text comprehension was investigated in two experiments. In the first experiment 20 subjects listened to three taped passages of equal length and difficulty varying in intonation (normal, monotonous, or altered) and were tested on tasks of text comprehension and word recognition. In the second experiment 20 new subjects read the same passages but with varying punctuation (appropriate, no punctuation, or altered) and were also tested on text comprehension and word recognition. Subjects' reading time was also recorded. ANOVA results revealed that altered prosody and punctuation affect performance in a similar fashion and seriously impair text comprehension and word recognition. This sensitivity to altered intonation suggests that linguistic prosody not only supplies redundant cues for judging sentence structure but that it also manages attentional resources to help with semantic encoding of lexical units and with the organization of linguistic information in long term memory.

Adult↗
PubMedDate not supplied

Language evolution in children with cochlear implants.

The capacity to incorporate significant words into the existing vocabulary and to use these words to form sentences with more mature syntactic structures emerges over a considerable time course in young deaf children who have undergone a cochlear implantation. The purpose of this follow-up study is to document the nature and time span of language production--in morphosyntactic and lexical skills--when a child's first experience with language sounds is provided artificially through electrical stimulation. To examine the development of these two aspects of linguistic processing, five deaf French children, all enrolled in similar postimplantation educational settings, were individually assessed at 6-month intervals over a period of 18 months. Computerized analyses were derived from their spontaneous speech in a 20-min standardized play session. Results for mean length of utterance and vocabulary revealed gradually improving performance for most children, in spite of the generally low starting point. Both measures of production nevertheless remained well below the norms established for normally hearing children. Although the achievement of higher production scores, which underlies more effective interpersonal exchanges, is evident after only 1 year of device use, it is clear that improvement does not always occur at the same pace, as shown by two of the children. This emphasizes the importance of longitudinal studies in documenting intersubject variability and intrasubject stability throughout the experience with an implant.

Child Language↗
PubMedDate not supplied

Short-term memory impairment and unilateral dichotic listening extinction in a child with Landau-Kleffner syndrome: auditory or phonological disorder?

The neuropsychological profile of a child with a Landau-Kleffner syndrome is presented here. The observed cognitive difficulties included verbal short-term memory and seemed partially compensated for when the experimental assessments bypassed the auditory channel. This case study is especially challenging since the child, whose phonological skills were quite efficient and who exhibited a dichotic listening unilateral extinction, had developed average reading and spelling abilities. The fact that B.E.'s performance on memory tasks was quite poor when the stimuli were presented auditorily and more efficient when the stimuli were presented visually, strongly suggests that the observed memory impairment was due to a deficit at the level of cortical auditory processing. B.E.'s phonological skills were efficient, suggesting a neuropsychological dissociation between phonological ability and auditory processing. The fact that B.E. dramatically recovered language and easily acquired reading and spelling accounts for the hypothesis that compensatory strategies allowed him to develop phonological skills from predominantly visual input.

Auditory Perceptual Disorders↗
PubMedDate not supplied

Ability of caregivers to read delayed hypersensitivity skin tests in children exposed to and infected by HIV. The Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted HIV Study Group.

OBJECTIVES: To identify whether nonmedical home caregivers (parents, guardians) could accurately interpret the results of delayed hypersensitivity skin tests in children, thereby obviating the need for a return visit for a professional reading. METHODS: Patients who were enrolled in the Pediatric Pulmonary and Cardiac Complications of HIV (P2C2HIV) study were given annual skin tests to tuberculin purified protein derivative, Candida, and tetanus as part of the study protocol. Caregivers were instructed verbally about how to read and measure erythema and induration. They were given written instructions to take home as well and were asked to return in 48 to 72 hours for the professional reading. On the morning of their return visit, they were to read the skin tests and record the results before coming to the clinic. RESULTS: When compared with readings by professional staff, caregivers had a high percentage of false-negative readings for both Candida (24%) and tetanus (41%) skin tests. These false-negative readings did not correlate with age, gender, race, or educational level of the caregivers. CONCLUSIONS: The high percentage of false-negative readings by the caregivers emphasizes the need for professional reading of delayed hypersensitivity skin tests.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Xanthogranulomatous appendicitis--an incidental finding of localized pathology.

The clinical, histopathological, and electron microscopic features of an unusual case of xanthogranulomatous appendicitis are reported. The patient, a 37-year-old female, presented with typical signs of acute appendicitis and the appendix appeared slightly dilated at laparatomy. The histopathological sections showed numerous xanthoma cells mixed with inspissated fecaliths. Electron microscopy disclosed the presence of xanthoma cells filled with electron-lucent lipid droplets of variable size. The ultrastructural characteristics of these cells enabled the distinction of two types of lipid-laden histiocytes, in relationship to the size of the lipid droplets. Since the lipid droplets were seen also in cells other than histiocytes, it appears that these changes are secondary to a common mechanism, comprising factors such as obstruction, hemorrhage, inflammation, and local hypoxia.

Adult↗
PubMedDate not supplied

Protein synthesis inhibition and cardiac lesions associated with deoxynivalenol ingestion in mice.

Deoxynivalenol (DON), an occasional contaminant of foodstuffs, has been implicated in outbreaks of mycotoxicosis. Balb-c mice that had ingested 0.35 mg/kg of DON showed a drastic decrease in food intake and concomitant loss of weight. Severe depletion of the lymphoid organs and liver were also observed. Cardiac lesions, appeared as calcified pericarditis foci in young animals fed a diet contaminated by 10 to 20 ppm of DON for a period of a few weeks. DON inhibited protein synthesis. This inhibition occurred at lower doses for the heart than for the other organs. This preferential effect on cardiac tissue correlated with the cardiotoxicity observed.

Administration, Oral↗
PubMedDate not supplied

Ethnic difference in duration of pregnancy.

It is suggested that the observed difference in duration of pregnancy between Blacks and Whites is partly physiological since it is not entirely explained by social inequities alone. This study compares women with well-defined gestational periods seeking attention at the Antoine Béclère Maternity Clinic. Group A consists of French women of European ancestry, Group B, those born in the French Antilles of mixed ancestry, and Group C black African women with insignificant European admixture. When compared to Group A, within each socio-economic class, group B and C have shorter gestational periods. These differences persist after adjustment for socio-economic variables, so that other explanations should be considered, specifically genetic determinants.

Africa↗
PubMedDate not supplied

The representation of semantic categories in aging.

Age differences in the representation of semantic information may underlie the cognitive decline observed in aging. The objective of the present study was to determine to what extent elderly and young subjects agreed in the representations of semantic categories. Ninety elderly (77 women, 13 men) and 90 young (74 women, 16 men) participants wrote down the first four associations evoked by each of 30 semantic category names. Results showed differences between the two groups in items selected as most common responses (MCRs); frequency of occurrence of the MCRs differed between the two groups in 21 semantic categories. Results suggest that young and elderly subjects hold different representations of semantic categories and also highlight the importance of using age-appropriate norms in the evaluation of cognitive functions in aging.

Aged↗
PubMedDate not supplied

Copper exposure and metal fume fever: lack of evidence for a causal relationship.

A systematic search was made of the world literature concerned with possible adverse health effects of inhalation exposure to copper fume and dust. Seven reports published over the past 88 years were identified that contain original human data and purport to document that exposure to copper dust or fume caused metal fume fever (MFF) or an MFF-like syndrome. Insufficient evidence was found to conclude that exposures to copper dust and copper fume cause MFF. Limitations included absence of exposure measurements, atypical symptoms and complaints, and lack of consistency among types of work associated with symptoms. Given the extensive use of copper in many industries and operations, it is evident that if copper-induced MFF does occur, it is a rare event.

Causality↗
PubMedDate not supplied

Two injections of diphtheria-tetanus-pertussis-polio vaccine as the backbone of a simplified immunization schedule in developing countries.

From studies of antibody levels induced against poliovirus types 1, 2, and 3 and against diphtheria and tetanus toxins as well as from epidemiologic studies comparing the protective effect in children of two and three doses of diphtheria-tetanus-pertussis (DTP) vaccine, respectively, it can be concluded that two injections of DTP-polio vaccine administered at least four months apart will induce immunity against the four diseases. An immunization schedule can be built up in which bacille Calmette-Guérin (BCG) vaccine is given simultaneously with the first DTP-polio injection at the age of three to eight months and vaccination against measles and--if needed--yellow fever is performed simultaneously with the second DTP-polio immunization at the age of nine to 14 months.

Developing Countries↗
PubMedDate not supplied

Effect of Zanchol and chenic acid on bile acid pool size and gallstones in hamsters.

After receiving a lithogenic regime for 12 weeks (Phase I), 60 hamsters were allocated to groups of 10 animals. During Phase II, except for one group which remained on the lithogenic regime, all groups were switched to a standard diet and chenic acid 20 mg/kg/day or Zanchol 5, 15 or 25 mg/kg/day or no other therapy. Half the animals in each group were sacrificed at 3 weeks and the remainder at 10 weeks. Gallstones were found in all animals except those receiving chenic acid for 10 weeks. At 3 weeks in Phase II, with chenic acid, the bile acid pool size was not significantly decreased and bile remained saturated despite a 38% lower rate of hepatic synthesis of cholesterol (p less than 0.01), but became unsaturated at 10 weeks at which time the bile acid pool size was increased by 37% (p less than 0.01). The highest at which time the bile acid pool size was increased by 37% (p less than 0.01). The highest dose of Zanchol increased the bile acid pool size by 74% (p less than 0.01) while increasing the hepatic synthesis of file acid by 38% (p less than 0.01). None of the doses of Zanchol, however, significantly changed biliary cholesterol saturation. In conclusion, chenic acid decreased the hepatic synthesis of cholesterol prior to increasing the bile acid pool, unsaturating bile and dissolving gallstones. Zanchol did not affect the biliary cholesterol saturation of dissolve gallstones despite an increase in the synthesis and pool size of the bile acids.

Animals↗
PubMedDate not supplied

Serum vitamin B6 in schizophrenic and schizoaffective patients with and without tardive dyskinesia.

There are several reports regarding the efficacy of vitamin B6 in the treatment of tardive dyskinesia (TD). Vitamin B6 plays a key role in the synthesis of several neurotransmitters, including serotonin, dopamine, norepinephrine, and gamma-aminobutyric acid, all of which have been proposed to be involved in the development of TD. The purpose of this study was to examine whether there are special markers to distinguish long-term neuroleptic exposure patients who have TD from those patients who do not develop this side effect. In view of the pivotal role of vitamin B6 in the synthesis of all neurotransmitters believed to take part in the pathogenesis of TD, we decided to examine whether basal levels of vitamin B6 might explain the difference between these two groups. Such a finding could provide a predictive marker for vulnerable patients. The active metabolite of vitamin B6 is pyridoxal phosphate (PP). Pyridoxal phosphate blood levels were measured in 15 schizophrenic and schizoaffective patients with TD and compared with 15 patients without evidence of TD (matched by sex, age, smoking, and diagnosis). We found that, although patients in the TD group were exposed to neuroleptic drugs for significantly longer periods of time, there were no differences in serum PP levels between the groups. The reports of the effectiveness of vitamin B6 supplementation in the treatment of TD could therefore be explained by the assumption that central nervous system or intracellular vitamin B6 levels, which are involved in the pathogenesis of TD, are not the same as vitamin B6 peripheral serum levels. There is need for further studies, which will clarify the relationship between vitamin B6 and TD.

Adult↗
PubMedDate not supplied

Reversal of pathologic cardiac parameters after transition from clozapine to olanzapine treatment: a case report.

Antipsychotic medications have been associated with significant cardiovascular adverse effects and instances of sudden cardiac death. Recently, we started to evaluate cardiac parameters in medicated patients with schizophrenia using power spectrum analysis of heart rate variability. We present a case of a patient with long-standing schizophrenia who was treated with clozapine. His electrocardiogram revealed minor abnormalities, including a prolonged QT interval. Power spectrum analysis of heart rate variability demonstrated marked abnormalities in autonomic nervous system activity. Two years later, his treatment was switched to olanzapine. We reevaluated his cardiac parameters. Power spectrum analysis studies revealed that heart rate had significantly improved and that power spectrum cardiovascular parameters had returned to normal. Serial electrocardiograms revealed a minimally and asymptomatically prolonged QT interval. This case demonstrates the importance of screening electrocardiograms, even in healthy young patients. It also emphasizes how minor changes in electrocardiogram can be overlooked on standard electrocardiograms. Power spectrum analysis of heart rate variability is useful in this instance because it magnifies the trace and detects even minor disturbances. Care should be taken in prescribing antipsychotic drugs to patients who are prone to cardiovascular side effects, and alternatives to antipsychotics with prominent anticholinergic profile, in particular, should be sought.

Adult↗
PubMedDate not supplied

Phosphorous burns: evaluation of various modalities for primary treatment.

White phosphorus is used in many types of military munitions, in fireworks, and in industrial and agricultural products. It ignites spontaneously and causes deep thermal injuries. It may also cause multiorgan failure because of its toxic effects on erythrocytes, liver, kidneys, and heart. Our previous studies demonstrated deleterious effects of copper sulfate. Only copious water irrigation was effective. This study examined other modalities of treatment and a free oxygen radical scavenger. One of the treatments seemed to have some beneficial effects, but simple water irrigation was much more effective. Superoxide dismutase, a free radical scavenger, reduced hepatic damage and adjacent skin flap destruction but did not prevent death of the animal receiving the high dose of white phosphorus used in the present setup.

Animals↗
PubMedDate not supplied

Power spectral analysis of heart rate variability in psychiatry.

Power spectrum analysis of heart rate variability (PSA of HRV) is a promising method, which can be used as an index of cardiac autonomic balance. PSA of HRV is a noninvasive technique, based on ECG sampling of RR interval variation, thus providing a dynamic assessment of sympathetic and parasympathetic tone, reflecting the interactions between the two. It has been shown to have potential value in various laboratory and clinical conditions. It is influenced by many factors such as age, sex, position, breathing, smoking, hour of the day and medications. Different methods of data processing by various authors have often elicited conflicting results. Standard values are not yet available to be used or compared in different settings. From the interest it has raised, it may be expected that this method will be in widespread use in clinical practice in the future, providing a useful tool, both for diagnostic and prognostic purposes, as well as serving as a further aid towards monitoring therapeutic interventions. This review highlights techniques of dynamic assessment of HRV and studies of its clinical applications in psychiatry in particular. It raises the potentially important prognostic implications of protracted autonomic dysfunction in psychiatric patient populations, especially for cardiovascular morbidity and mortality.

Analysis of Variance↗