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Biomedical subjects

R Cohen

Publications and source records attributed to R Cohen.

At least 217 records · Page 12Linked to original sources
PubMed1996

Effects of fish oil on metabolic responses to oral fructose and glucose loads in healthy humans.

This study examines the effect of the substitution of 6 g/day of fish oil in a saturated diet on glucose and fructose metabolism in healthy humans. Five subjects were submitted to two 3-wk controlled-diet periods (polyunsaturated/saturated = 0.21). During one period, 6 g/day of fat used for dressing were replaced by 6 g/day of fish oil [1.1 g/day of 20:5 (n-3) fatty acids and 0.7 g/day of 22:6 (n-3) fatty acids]. At the end of each period the subjects ingested a 1 g/kg fructose or glucose load 2 days apart. Plasma glucose fluxes were traced with the use of deuterated glucose and [U-13C]glucose. Substrate oxidation was measured by indirect calorimetry. Fish oil induced a 4% increase in basal and postload glycemia and a 40% decrease in insulinemia, whereas plasma C-peptide remained unaffected. Glucose fluxes were unaffected by fish oil, but carbohydrate (CHO) oxidation was reduced (fructose: 55.5 +/- 4.1 vs. 62.9 +/- 3.6 g/6 h; glucose: 36.7 +/- 4.7 vs. 50.5 +/- 4.7 g/6 h; all P < 0.05). Lipid oxidation was increased 35% by fish oil after both CHO loads. Nonoxidative glucose disposal was increased by fish oil (fructose: 9.4 +/- 2.5 vs. 2.9 +/- 1.1 g/6 h; glucose: 28.3 +/- 5.1 vs. 14.4 +/- 4.7 g/6 h; all P < 0.05). Fish oil could affect glucose transport and decrease CHO oxidation through the decrease in insulinemia and/or a specific effect on glycolytic pathway.

Administration, Oral↗
PubMed1996

Metabolic fate of an oral long-chain triglyceride load in humans.

To determine the steps involved in the metabolism of ingested triglycerides (TG), 10 healthy women were studied during 6 h after ingestion of 30 g olive oil labeled with [1,1,1-13C3] triolein. The appearance of 13C was followed in chylomicron-TG (CM-TG), nonesterified fatty acid (NEFA), very low-density lipoprotein (VLDL)-TG, and in expired gas. Indirect calorimetry was used to determine total lipid oxidation. After 90 min, labeling was higher in CM-TG than in NEFA or VLDL. At 180 min, a plateau of enrichment was obtained for CM-TG and NEFA, demonstrating the entry of exogenous lipids in the NEFA pool. After 300 min, a plateau was observed for VLDL-TG with levels of enrichment (0.38 +/- 0.04%) similar to those observed for NEFA (0.36 +/- 0.03%), suggesting a precursor-product relationship. Only 19 +/- 2% of the load was oxidized. From 300 to 360 min, 70% of total lipid oxidation was from exogenous TG. We conclude that, after ingestion of a lipid load, a cycle of fatty acids-TG occurs from CM to NEFA and from NEFA to VLDL. Furthermore, this lipid load has a sparing effect on endogenous lipid stores.

Adult↗
PubMed1996

Intradialytic parenteral nutrition after small bowel resection.

Malnutrition is frequently observed in the hemodialysis patient population. It may be associated with increased morbidity and mortality as well as affect overall quality of life, which may already be compromised from dialytic physical and psychological demands. In the past, intradialytic parenteral nutrition (IDPN) has been available to hemodialysis patients as an adjunct to their dietary intake. In this time of cost containment and the increasing need to scientifically justify the benefit of such therapies to have them paid for by third party reimbursers, IDPN is coming under much scrutiny. This report describes a case of inadequate enteral nutrient absorption in a malnourished hemodialysis patient. This is a case in which IDPN was beneficial and without which other alternatives would have proven more costly physically, emotionally, and economically to the patient.

Aged↗
PubMed1996

The consistency and uncertainty in examiners' definitions of pass/fail performance on OSCE (objective structured clinical examination) stations.

The Medical Council of Canada has made use of examiners' pass/fail classifications of candidates' behaviors in objective structured clinical examination (OSCE) stations in defining cutting scores for these stations. This process assumes that there is consistency in the judgments of examiners employed in the same stations at different testing sites and in the cutting scores derived from these judgments. These assumptions were tested using the results of the fall 1993 administration of part 2 of the Medical Council of Canada's Evaluating Examination to 744 candidates. The results of this study provided evidence of the consistency of the pass/fail and cutting score definitions for the stations used across examiners.

Canada↗
PubMed1996

The validity of classic symptoms and chest radiographic configuration in predicting pulmonary tuberculosis.

OBJECTIVE: Patients admitted to the pulmonary isolation service to rule out tuberculosis (TB) were prospectively studied to identify predictors of smear-positive TB. METHODS: History of symptoms--cough, sputum production, fever, weight loss, night sweats, hemoptysis, anorexia, and dyspnea; medical history--TB, tuberculin skin test (TST) status, TB contact; and social factors--crowding index, history of incarceration or living in a shelter, and employment status were obtained in face-to-face interviews. Chest x-rays (CXRs) were scored as typical, atypical, or negative. Serial morning sputa were collected. RESULTS: Complete data were collected on 101 patients; 44 had pulmonary TB; 33 patients were smear positive and considered infectious; 11 patients were smear negative but culture positive. There was no difference between TB and non-TB patients with respect to HIV status and social risk factors. Significant differences were found between patients who were smear positive for TB and smear negative with respect to cough, sputum, and typical CXR (79%, 76%, and 79% sensitivity, respectively). Eleven patients without TB had an atypical CXR and denied cough, sputum, and weight loss. Only one patient with TB presented this way. CONCLUSION: Even in high-risk populations, symptoms of cough, sputum, weight loss for less than 2 weeks, and the absence of a typical CXR are strong negative predictors for TB.

Female↗
PubMed1996

Performance of immunoassays for ca 19-9, ca 15-3 and ca 125 tumour markers evaluated from an international quality assessment survey.

Data collected in the 1993 and 1994 cycles of an international External Quality Assessment (EQA) programme were cumulatively analysed to evaluate the analytical performance of the methods currently in use for routine assay of mucinous tumour markers CA 19-9, CA 15-3 and CA 125. On average the between-laboratory variability was 14.7 and 15.8 CV% for CA 15-3 and CA 125 respectively. For CA 19-9, a markedly worse between-laboratory variability (on average 27.2 CV%) was found; the agreement of CA 19-9 results worsened in the last few years when new isotopic techniques became available. The variability component attributable to systematic differences between methods/kits was relatively small for CA 15-3 and CA 125 (17% and 21% of the total variability), while it was markedly larger for CA 19-9 (45% of the total variability). The precision of the methods/kits most often used in the survey ranged from 9.6 to 13.9 CV% for CA 125 and from 10.8 to 14.1 CV% for CA 15-3. For these two tumour markers the precision of the traditional IRMAs does not appear to be different from that of the new fully automated non-isotopic techniques. The precision of CA 19-9 methods was on average worse from (11.9 to 19.2 CV%), even though the precision of the two automated systems was better than that of IRMAs. In conclusion, the results of this study indicate that the between-laboratory agreement for CA 15-3 and CA 125 assays appears satisfactory while the CA 19-9 assay shows larger differences between methods and is affected by poorer precision of kits.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1996

6-day amoxicillin versus 10-day penicillin V for group A beta-haemolytic streptococcal acute tonsillitis in adults: a French multicentre, open-label, randomized study. The French Study Group Clamorange.

We compared the efficacy and safety of amoxicillin 1 g b.i.d. for 6 days and penicillin V 1 MU t.i.d. for 10 days in the treatment of group A beta-haemolytic streptococcal (GABHS) tonsillitis in adults. 342 patients with acute tonsillitis and a positive test for streptococcal antigen were included in a multicentre, randomized, open-label study; 338 patients were evaluable in an intention-to-treat analysis, and 234 with a positive throat swab culture in a per-protocol analysis. In the per-protocol analysis, the GABHS eradication rate at the end of treatment was comparable in the two groups: 92% (115/125) on amoxicillin and 92.7% (101/109) on penicillin (p = 0.95), as were the clinical success rates of 96% and 95.4%, respectively (p = 0.92). At the follow-up visit (day 28-32), 90.8% of patients treated with amoxicillin and 92.6% of those treated with penicillin V were free of GABHS (p = 0.85). Sore throat disappeared significantly faster on day 2 (p = 0.039) in the amoxicillin group. The intention-to-treat analysis gave similar clinical results. Tolerability was good in both groups. The efficacy and safety of amoxicillin 1 g b.i.d. for 6 days were not statistically different from those of penicillin V 1 MU t.i.d. for 10 days in the treatment of streptococcal tonsillitis in adults.

Acute Disease↗
PubMed1996

Longitudinal epiphyseal bracket: associated foot deformities with implications for treatment.

The longitudinal epiphyseal bracket is a rare ossification defect of bones of the hands and feet and results in an abnormal epiphysis that is C-shaped, longitudinally oriented, and vertically extends into the diaphysis. The longitudinal epiphyseal bracket may exist as an isolated deformity, but is commonly associated with digital deformities such as polydactyly, duplicated digits, congenital hallux varus, and clinodactyly. Five case histories of children with the longitudinal epiphyseal bracket in different bones of the foot are described with three distinct clinical presentations. The development of the longitudinal epiphyseal bracket and implications for treatment are considered.

Adolescent↗
PubMed1996

Behavior segmentation by boys as a function of aggressiveness and prior information.

Previous research documents a hostile attribution bias by aggressive boys when considering a social situation with ambiguous cues as to the intention of the participants. The present research evaluated whether this bias extends to the manner in which boys process incoming information. Aggressiveness of boys in grades 3-6 was assessed with peer behavior nominations. In a separate session, each child viewed a videotape of 2 boys playing tag on a playground and segmented the actions using a standard behavior segmentation procedure. A critical event occurred when one of the boys fell down after being tagged, slowly got up, then resumed the game. Prior to viewing the videotape each child received one of three information conditions: benign (the boys were friends), hostile (the boys did not like one another), or neutral (no specific information about the relationship between the boys). Aggressiveness predicted change in segmentation after the critical event only in the neutral prior information condition. Thus aggressiveness, found in other research to be associated with a hostile attribution bias, also was found to be related to differences in the organization of incoming information.

Aggression↗
PubMed1996

Ventricular laceration and cardiac tamponade during laparoscopic Nissen fundoplication.

Laparoscopic fundoplication is now accepted as an excellent alternative to long term medical therapy for select patients with gastroesophageal reflux disease. Morbidity is uncommon and usually not life threatening. The procedure requires retraction of the left lateral segment of the liver, which has emerged as one of the most troubling technical aspects. This case report represents an uncommon, albeit dramatic, complication involving traumatic injury to the right ventricle thought secondary to trauma from a non-disposable, fan shaped, liver retractor.

Aged↗
PubMed1996

The development of occupational aspirations and expectations among inner-city boys.

The occupational aspirations and expectations of two populations of boys in grades 2, 4, 6, and 8 were examined in order (1) to describe what is unique about the development of job preferences among urban ghetto children who live in settings where many adult males are not well attached to the labor force and (2) to examine 6 reasons for any age- and population-dependent patterns there might be in job aspirations and job expectations. Findings show that boys tend to be more realistic about occupational aspirations and expectations the older they are; that from second grade on the occupational expectations of inner-city boys mirror existing race and class differences in adult job holdings; that the gap between occupational aspirations and expectations is greater for the ghetto boys and remains roughly constant in size across the grades examined; and that the lower occupational expectations of the inner-city boys are strongly related to their lower educational expectations, with these educational expectations being associated with fewer poor boys having a biological father at home and with more of these boys seeing obstacles to success in the local social setting. But, the lower occupational expectations of the ghetto boys are not due to having fewer positive role models or believing that schooling will not pay off for them in the future as it does for others.

Adolescent↗
PubMed1995

Benzodiazepine receptors mediate regional blood flow changes in the living human brain.

We studied the effects of a high-affinity gamma-aminobutyric acid (GABA)-benzodiazepine-receptor agonist (lorazepam) and an antagonist (flumazenil) in humans, using H2(15)O positron-emission tomography. Administration of lorazepam to healthy volunteers caused time- and dose-dependent reductions in regional cerebral blood flow and self-reported alterations in behavioral/mood parameters. Flumazenil administration reversed these changes. These observations indicated that benzodiazepine-induced effects on regional cerebral blood flow and mood/behavior are mediated at some level through GABA-benzodiazepine receptors, although the specific mechanism remains unclear. The approach described here provides a method for quantifying GABA-benzodiazepine-receptor-mediated neurotransmission in the living human brain and may be useful for studying the role of these receptors in a variety of neuropsychiatric disorders.

Adult↗
PubMed1995

Smooth-pursuit eye-movement dysfunction and motor control in schizophrenia: a follow-up study.

Smooth-pursuit eye-tracking data of 63 schizophrenic patients and 52 normal controls are presented and compared with data collected on the same subjects 2 years earlier. Despite considerable clinical stabilization of the patients the overall eye-tracking performance did not improve. Intrasubject stability over 2 years was moderate. Eye-tracking impairment was significantly correlated with number of psychomotor soft signs and with number of errors in an antisaccade task. The correlations indicate that impairment of smooth-pursuit eye movements is likely to be a consequence of deficient motor control.

Adult↗
PubMed1995

Affective modulation of the startle reflex in schizophrenic patients.

Startle-elicited blinks were measured during the presentation of affective slides in order to investigate emotional responsiveness in 24 male healthy subjects and 34 male schizophrenic patients. Although the two groups did not differ with regard to their subjective and autonomic responses to the slide stimuli, there was a significant difference between the groups in their responses to the startle probes. Patients rated low in affective expression showed a linear response pattern comparable to that of normal controls with largest amplitudes during unpleasant slides and smallest during pleasant slides. Patients without apparent deficit in affective expression showed a quadratic relationship with smaller blink amplitudes during both pleasant and unpleasant slides. Diminished affective expression rated on the basis of a clinical interview is not associated with a general attenuation of the blink reflex or of its modulation by exposure to emotional slides. Thus, we found no indication of an impairment in the perception of affective stimuli nor of reduced appreciation of pleasant stimuli (anhedonia) in these patients.

Adult↗
PubMed1995

Electrodermal and vascular orienting response in schizophrenic patients: relationship to symptoms and medication.

Peripheral indicators of autonomic nervous system activity, including electrodermal activity and finger-pulse volume, were investigated in 100 schizophrenic inpatients. Healthy siblings of the patients and healthy subjects matched for age and gender served as control groups. Acoustic stimuli (70 dB) were presented and orienting response (OR) parameters were determined independently for the two response systems. The relationship of both OR measures to negative symptoms and medication was studied. The two OR measures were found to be not interrelated, i.e. most of the subjects were discordant with regard to presence or absence of their OR in the two different response systems. The electrodermal, but not the vascular OR, differed between patients and control groups. Among patients receiving medication with anticholinergic effects there were significantly more electrodermal nonresponders than among patients without such medication. There was no indication that electrodermal nonresponders show more negative symptoms or generally more severe psychopathology than electrodermal responders.

Adult↗
PubMed1995

Interleukin-2 and interleukin-4 display potent antitumour activity on rat medullary thyroid carcinoma cells.

Currently, surgical resection is the only treatment used for human medullary thyroid carcinoma (MTC). However, as metastases are commonly observed, we investigated the potential of adjuvant therapy with interleukin-2 (IL-2) and interleukin-4 (IL-4) in a rat model. The interleukins were delivered by means of xenogeneic tumour cells engineered to secrete IL-2 and IL-4. We found that when a mixture of MTC cells and IL-2 or IL-4 secreting cells were implanted in rats, the growth of the resulting tumours was inhibited as a function of the number of interleukin-secreting cells in the inoculum. Moreover, association of the two interleukins exerted a synergistic antitumour effect. These experimental results, showing thyroid C cell tumour rejection, are of major interest, as they show the potential therapeutic application for these two interleukins, which could be used, in particular, as postsurgical adjuvants.

Animals↗
PubMed1995

Station gender bias in a multiple-station test of clinical skills.

PURPOSE: To apply differential item functioning (DIF) procedures to investigate station gender bias in multiple-station tests of clinical skills, and to compare these results with those obtained by comparing the station-score distributions of men and women examinees. METHOD: The data were from 23 stations used in the selection of seven successive cohorts (1987-1993) of candidates to the Ontario Pre-Internship Program for graduates of foreign medical schools. The stations had been used on at least three occasions, with a minimum sample of about 210 candidates per station. Each station's score was expressed as both a binary score and a continuous score, and DIF was assessed using the Mantel-Haenszel procedure with the binary scores and analysis of covariance with the continuous scores. For each station, DIF effect sizes were calculated and compared with the gender-group mean differences. RESULTS: Using the binary scores, significant DIF was observed for three stations; using the continuous scores, significant DIF was observed for five stations. Significant gender differences were observed in the scores of nine stations. In eight, these differences favored women. Overall, in more stations the direction of DIF favored the men, while the women demonstrated higher levels of ability. CONCLUSION: The results suggest the importance of using a DIF approach for controlling the "ability factor" in studies of this kind: although significant gender differences were observed in the continuous score distributions of nine stations, generally these differences were not indicative of station gender bias.

Analysis of Variance↗