Search PubMed⌕ Search

Biomedical subjects

R Cohen

Publications and source records attributed to R Cohen.

At least 379 records · Page 21Linked to original sources
PubMed1990

Development of competence in clerkship.

Students' perceptions of their educational experience on Surgery and Medicine rotations of a clerkship program were analysed. Six components of the education process, namely (1) frequency of individual teaching, (2) quality of contact with staff-clinicians, (3) appropriateness of responsibility for patient care, (4) appropriateness of supervision received, (5) frequency of admissions reviewed and (6) frequency of opportunity to follow-up patients admitted, were correlated with students' confidence in their ability to function competently. Mean scores of clerks' confidence in their competence was the same for both rotations. Breakdown by sex revealed females to feel more competent on medicine, and males on surgery. On the medicine rotation a moderate relationship was found between two of the components tested and the dependent variable; on surgery, strong correlations were found between four of the components tested and the dependent variable. Regression analysis demonstrated appropriateness of responsibility for patient care to have a low predictor value for achievement of competence on medicine, while quality of contact with staff-clinician and appropriateness of supervision received were strong predictors of achievement of competence on the surgery rotation.

Attitude of Health Personnel↗
PubMed1990

The surgeon simulator.

A new technique of small group surgical teaching has been developed wherein the surgeon takes on the role of the patient. This technique, which incorporates extensive and immediate formative evaluation, has all the advantages of simulation techniques while avoiding the major problems of training, scheduling and cost. This method has been used to teach a wide variety of surgical disease processes with the major emphasis being teaching patient management strategies. Sixty-one medical students have been taught using this method and they have found it superior to conventional seminar teaching, particularly in the domains of problem solving, patient management strategies and thought provocation.

Education, Medical, Undergraduate↗
PubMed1990

[Brucellosis in a 3 month-old infant].

During the course of a bronchiolitis in a 3 month-old child, one blood culture yielded Brucella melitensis. The diagnosis of brucellosis is difficult in infancy because the symptoms are nonspecific and the disease may be mild and self-limited. The child received only breast milk and dietetic preparations. So, the detection in the maternal serum of a significant titer of Brucella agglutinin enabled us to consider the very rare human-to-human transmission from mother to child. Because the efficacy of ceftriaxone assessed by a favorable initial response, and in order to avoid complications due to the use of tetracyclines and cotrimoxazole in infant, our patient was successfully treated with ceftriaxone plus rifampin.

Breast Feeding↗
PubMed1990

[Low density lipoprotein (LDL) heterogeneity and atherosclerosis].

LDL particles constitute the predominant form of transport of cholesterol towards tissues, and a major risk factor for atheroma. The pathogenesis of atherosclerosis is, as yet, far from completely elucidated and, indeed, within the LDL particles themselves, there is a structural heterogeneity. Approximately fifteen subfractions have been isolated so far, presenting differing profiles in normal and hyperlipidemic subjects. Some of these subgroups seem to be linked with an atherogenic potential, this is the case for the smaller and the more dense of the particles. LDL particles are normally cleared from the blood stream via the BE receptor, whose synthesis is regulated by the intracellular content of cholesterol. The particules must however undergo several, in vivo and in vitro, transformations which modify their metabolism and are all the more important when their half life is prolonged. These transformations, and in particular oxydation, lead, via the macrophage pathway, to the accumulation of cholesterol, the creation of foam cells, and ultimately to the formation of the lipid streak. Antioxydants therefore open the way to new therapeutic pathways by acting in synergy with cholesterol lowering agents.

Arteriosclerosis↗
PubMed1990

[Randomized study of cefatrizine versus cefaclor in conjunctivitis otitis syndrome].

The association conjunctivitis-otitis is highly suggestive of Haemophilus influenzae infection. This conjunctivitis otitis syndrome could be a good model to assess the efficacy of different antibiotic regimen in the treatment of acute otitis media due to HI without tympanocentesis. This prospective randomized trial compared the efficacy of two orally cephalosporins which demonstrate in vitro an activity against HI. This study was conducted from 4.20.1988 to 3.15.1989 and involved 73 children with COS examined in an outpatient clinic. The mean age was 17.7 months. Before treatment culture were taken from the lower palpebral conjunctivae. 81 strains was found: HI 61 (beta-lactamase-producing 15), Streptococcus pneumoniae 16, Branhamella Catarrhalis 4. The 73 patients were treated with 40 to 50 mg/kg/day of the test drug for ten days, 25 with Cefaclor in 3 divided dose (group 1), 24 with Cefatrizine in 3 divided dose (group 2), 24 with Cefatrizine in 2 divided dose (group 3). The recoveries was obtained in 17/25 in the group 1, 18/24 in the group 2, 15/24 in the group 3. There was no significant difference between the 3 groups.

Acute Disease↗
PubMed1990

Hormonal and metabolic effects of chronic interleukin-2 infusion in cancer patients.

Interleukin-2 (IL-2) is secreted during the immune response to trauma, sepsis, and transplant rejection. Its role in the development of the metabolic abnormalities observed in these circumstances is not well defined. We studied the clinical, hormonal, and metabolic response to a 5-day IL-2 infusion (3 x 10(6) U/m2/day) of nine patients with metastatic renal carcinoma. IL-2 induced systemic manifestations after a latent period of 4 h (fever, tachycardia) or 8 h (hypotension). These manifestations persisted until the end of the infusion. Insulin levels were not modified. Among the stress hormones, cortisol increased at the onset of fever and tachycardia, whereas the rise in catecholamines occurred later (24 h) and appeared more as a response to the development of hypotension. The only metabolic effects observed were a late (third day) rise of lactate and a late and transient (third to fourth day) decrease of glycerol and nonesterified fatty acids. These metabolic modifications were temporally related to the development of hypotension and result more likely from low tissue perfusion rather than from a direct or hormone-mediated effect of IL-2.

Adult↗
PubMed1989

The effect of organotin compounds on chloride secretion by the in vitro perfused rectal gland of Squalus acanthias.

The effects of various organotins on membrane function and electrolyte transport were studied in the marine elasmobranch, Squalus acanthias. The isolated perfused rectal gland was used as a model of electrolyte transport. This gland can be stimulated to secrete chloride by atrial natriuretic peptide, veratrine, and vasoactive intestinal polypeptide although the mechanism of action of each secretagogue is different. By analysis of the inhibitory effect of an organotin in the presence of each secretagogue, the mechanism of inhibition can be inferred. Tributyltin (TBT) produced a reversible inhibition of epithelial transport at 10(-8) to 10(-7) M which resulted from inhibition of stimulus-secretion coupling in VIP-containing neurons within the gland. The transporting epithelial cells were unaffected at these concentrations. Trimethytin (TMT) produced inhibition at 10(-7) M which was not reversible and which affected primarily the transporting epithelial cells. Triethyltin and triphenyltin were without effect. The inhibitory effect of TBT and TMT was not affected by simultaneous administration of dithiothreitol. TBT also produced inhibition of oxygen consumption, Na+,K-ATPase, and proton ATPase in dispersed rectal gland cells. These results indicate that organotins are toxic to cell membrane functions which are intimately involved in the movement of electrolytes. This is the first evidence of toxicity to membrane transport functions in a marine species which is at risk from environmental exposure.

Animals↗
PubMed1989

Elevated levels of calcitonin mRNA: a marker for the spontaneous development of medullary thyroid carcinoma in rats.

The aging WAG/Rij rats (a Wistar derived strain) develop spontaneously medullary thyroid carcinoma with a high frequency (50%). We have studied calcitonin biosynthesis in Wistar and WAG/Rij rats strains in order to determine if early changes in this parameter occurred in the WAG/Rij strain. Thyroidal and plasma CT levels were measured in three months old WAG/Rij and Wistar rats before and after acute calcium challenge. Total RNA was extracted from thyroid glands and specific CT messenger RNA levels estimated by dot and Northern blot analysis with a 32P-labeled probe specific for CT mRNA. The capacity of mRNA to direct synthesis of CT precursor was also measured by translation in an in vitro system. Though mean basal circulating CT levels were equivalent in both strains, CT release after calcium stimulation was much increased in the WAG/Rij rat. CT content of the glands and CT mRNA levels were two fold higher in the WAG/Rij strain. Thus, in this strain, CT biosynthesis and secretion were increased long before the development of a C-cell carcinoma.

Animals↗
PubMed1989

Neonatal hyperbilirubinemia at high altitude.

A previous retrospective study showed an increased frequency of neonatal hyperbilirubinemia at high altitude in Colorado. In a prospective study we found that 39% of newborns at 3100 m altitude vs 16% at 1600 m exhibited hyperbilirubinemia, defined as a day 3 serum bilirubin level of 205 mumol/L or higher. Increased bilirubin production at 3100 m vs 1600 m was shown by increased levels of corrected carboxyhemoglobin. This finding was supported by increased erythropoietin and bilirubin values in cord blood and increased hematocrit values at day 3 among infants at 3100 m vs 1600 m. The sustained elevation in bilirubin for breast-fed vs formula-fed infants at 1600 m was observed for both feeding types at 3100 m. The findings suggested that there is a hematologic response to decreased oxygen availability at high altitude, resulting in increased bilirubin production accompanied by delayed bilirubin clearance.

Adult↗
PubMed1989

A developmental analysis of the influence of body weight on the sociometry of children.

The influence of relative weight on sociometric nominations (liking and disliking) and sociometric ratings by first, third, and fifth graders was assessed. In terms of nominations, first grade overweight males, relative to other males and to overweight females, received fewer liking nominations. On the sociometric ratings, third grade overweight males were rated lower by other males. Ratings by females at each grade level, and by fifth grade males, were influenced by gender considerations and not by weight considerations. That is, boys rated boys higher than they rated girls, and girls rated girls higher than they rated boys, regardless of the child's weight status. Additional analyses demonstrated that these findings were not qualified by the weight of the child making the ratings. Thus, developmental evidence was found for less liking (but not disliking) of overweight peers among first and third grade males, while weight did not appear to influence the decisions of fifth graders. These results call into question the validity of a social stigma often assumed to be associated with overweight children.

Body Weight↗
PubMed1989

Xanthogranulomatous pyelonephritis and amyloidosis: a rare association.

The coincidence of systemic amyloidosis and xanthogranulomatous pyelonephritis has been reported previously only once. Clinical findings, such as the nephrotic syndrome, cardiac and autonomic nervous system dysfunction, and adrenal insufficiency, are suggestive and a thorough investigation to rule out other causes of secondary amyloidosis is warranted. We report a case of xanthogranulomatous pyelonephritis associated with secondary systemic amyloidosis and the nephrotic syndrome. Treatment consisted of nephrectomy and intensive supportive care. The unique clinical, radiographic and pathological aspects of this case are discussed.

Amyloidosis↗
PubMed1989

Castleman's tumor and erosive lichen planus: coincidence or association?Report of a case.

The rare association of severe erosive lichen planus and Castleman's tumor is presented. Castleman's tumor, or giant lymph node hyperplasia, is a benign neoplasm resembling thymic tumors and is associated with several immunologic abnormalities. Lichen planus also is associated with immunologic defects. One hypothesis linking these two diseases is that lymphocytes may become sensitized to tumor antigens on the Castleman's tumor and attack cross-reacting structures in the skin and other stratified squamous mucosae to produce the clinical picture of lichen planus.

Adult↗
PubMed1989

Filling the preparatory interval with temporal information or visual noise: crossover effect in schizophrenics and controls.

Three variants of a simple reaction time task with regular and irregular series of different preparatory intervals (PIs) were presented to schizophrenics and a control group of alcoholics and normals: the visual warning signal (WS) either (1) remained fixed, (2) shrank at a constant rate, or (3) changed in size erratically. Time information provided by shrinking WSs reduced the average reaction time in all groups and attenuated the crossover effect (COE) of schizophrenics, although even here more schizophrenics than controls had COE-scores greater than or equal to 25 msec. Erratically changing WSs introduced the COE in controls. Within groups the COE was not related to general response speed, age, duration of hospitalization, or medication. Results are interpreted as indicating that schizophrenics eschew controlled anticipatory processes on the basis of WS- and PI-information which are crucial for motor preparation when PIs are too long to allow an automatic perceptual grouping of warning and imperative stimulus. This may also occur in controls when time estimation is impeded by distraction.

Adult↗
PubMed1989

Structural family versus psychodynamic child therapy for problematic Hispanic boys.

Structural family therapy, psychodynamic child therapy, and a recreational control condition were compared for 69 six-to-twelve-year-old Hispanic boys who presented with behavioral and emotional problems. The results suggest that the control condition was significantly less effective in retaining cases than the two treatment conditions, which were apparently equivalent in reducing behavioral and emotional problems as well as in improving psychodynamic ratings of child functioning. Structural family therapy was more effective than psychodynamic child therapy in protecting the integrity of the family at 1-year follow-up. Finally, the results did not support basic assumptions of structural family systems therapy regarding the mechanisms mediating symptom reduction.

Child↗
PubMed1989

Coding and recall of categorized material in aphasics.

The aim of the present study was to examine whether the often reported impairments of aphasics in different short-term memory tasks could be the result of a failure to use the facilitating strategy of clustering. Aphasics (n = 60), right hemisphere brain-damaged (n = 36) and normal (n = 10) controls were tested with a modification of tasks developed by Petrides and Milner (1982). They were presented with sets of 16 cards with a random arrangement of the same 16 stimuli. On each card subjects had to point to one of the stimuli, trying not to point to the same stimulus in different cards. In some of the tasks pictures were selected to suggest a clustering into four equally sized subsets; in others the stimuli were highly heterogeneous with respect to perceptual and semantic characteristics. Prior to each task with items easy to categorize, half of the subjects were requested to sort the pictures into subsets, while the other half were given the pictures without any specific instruction, having been requested to do the sortings only after the main task. Aphasics (1) showed less clustering, i.e., sequential pointing according to the predefined categories, and (2) made significantly more errors than RH-controls especially in the tasks easy to categorize. While RH-controls benefited from the preceding sorting of the pictures aphasics made more errors when first introduced to the categorization task.

Adolescent↗
PubMed1989

Control-related cognitions and depression among inpatient children and adolescents.

In previous studies, children with numerous depressive symptoms have shown two patterns of control-related cognition: (1) low levels of perceived personal competence, and (2) "contingency uncertainty"--confusion regarding the causes of significant events. The generality of these findings was tested for more seriously disturbed children. Three child inpatient samples, from separate psychiatric hospitals, completed the Children's Depression Inventory (CDI) plus measures of control-related beliefs. In all three samples, the findings resembled those of previous studies: CDI scores were significantly related to low perceived competence and to contingency uncertainty; by contrast, CDI scores were only weakly related to perceived noncontingency. The findings suggest that depressive symptoms in children may be (1) more closely linked to "personal helplessness" than to "universal helplessness," and (2) more closely linked to uncertainty about the causes of events than to firm beliefs in noncontingency. The findings carry implications for etiology and treatment of child depression.

Adolescent↗