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Biomedical subjects

H Cohen

Publications and source records attributed to H Cohen.

At least 253 records · Page 14Linked to original sources
PubMed1995

Auditory cerebral lateralization following cross-gender hormone therapy.

In this study, 10 men, 10 women, and 13 genetic male transsexuals, all of them righthanded, were tested on two verbal (CV and nonsense polysyllables) and two nonverbal (melodies and triple tone [3T]) dichotic tasks to investigate relations between hormone therapy and auditory cerebral specialization for speech and non speech stimuli in adults. At time of testing, all transsexuals had been made under hormonal treatment for at least one year and eight had had corrective surgery. ANOVA results showed a right ear advantage and similar pattern of performance for the three groups in the treatment of speech. In nonverbal tasks, interactions revealed a left ear advantage in the processing of melodies and 3T for men only: women and transsexuals exhibited similar performance in both nonverbal tasks. In accord with generalization from the animal literature, cautious interpretation of the data is some possible hormonal involvement, in adults, in the modulation of right hemispheric cognitive processing.

Adult↗
PubMed1995

Interobserver agreement and predictive value of endoscopic findings for H. pylori and gastritis in normal volunteers.

BACKGROUND: Endoscopic findings such as erythema are frequently labeled as gastritis. We sought to determine interobserver agreement for specific endoscopic features and assess the diagnostic value of features with good agreement for Helicobacter pylori and histologic gastritis. METHODS: Fifty-two healthy subjects without ulcers, erosions, or hemorrhages had a full endoscopy recorded on video tape. Biopsy specimens were examined for H. pylori and gastritis. Two endoscopists independently reviewed the tapes for predefined features (erythema, area gastricae, clefts, and nodularity) in the gastric body and antrum. Diagnostic value of endoscopic features with acceptable agreement (kappa > 0.40) was then determined for H. pylori and gastritis. RESULTS: Kappa was greater than 0.40 only for prominent body area gastricae (0.49), body nodularity (0.65), and antral nodularity (0.68). For antral nodularity, sensitivity was 32%, specificity was 96%, and positive predictive value was 90% for H. pylori. when both antral nodularity and body area gastricae were both present, sensitivity was only 18% but specificity and positive predictive value were 100%. CIRCULATION: Interobserver agreement is poor for some features such as erythema labeled as gastritis. Antral nodularity is a fairly reproducible finding and is very specific, though not sensitive, for H. pylori gastritis.

Adult↗
PubMed1995

Postinfectious purpura fulminans caused by an autoantibody directed against protein S.

OBJECTIVE: To determine the mechanism responsible for idiopathic purpura fulminans, we investigated the procoagulant and anticoagulant pathways in five consecutive patients, four after varicella, and the fifth after a nonspecific infection. METHODS: Procoagulant and anticoagulant factors, including protein C, protein S, and antithrombin III, were measured by quantitative or functional assays. Anti-protein S autoantibodies were identified by dot blotting and Western blotting, and quantified serially by enzyme-linked immunosorbent assay. Clinical and laboratory data were collated retrospectively. RESULTS: In each case the disease began 7 to 10 days after the onset of the precipitating infection, with rapidly progressive purpura leading to extensive areas of skin necrosis. The illness was complicated by impaired perfusion of limbs or digits (two patients), peripheral gangrene resulting in an above-knee amputation (one patient), and major organ dysfunction caused by thromboembolic phenomena involving the lungs (two patients), the heart (one patient), or the kidneys (one patient). Protein S levels were virtually undetectable at the time of admission and failed to respond to infusions of fresh frozen plasma, despite correction of other procoagulant and anticoagulant factors. All five children had anti-protein S IgM and IgG autoantibodies, which persisted for less than 3 months after admission. Decline in the anti-protein S IgG antibody concentration was associated with normalization of the plasma protein S levels. CONCLUSIONS: Autoimmune protein S deficiency may be a common mechanism causing postinfectious idiopathic purpura fulminans. Recognition of the pathophysiologic mechanism may provide a rational basis for treatment. Immediate heparinization, infusions of fresh frozen plasma, and, in cases complicated by major vessel thrombosis, the use of tissue-type plasminogen activator may limit thromboembolic complications.

Acute Disease↗
PubMed1995

Prevention of blinking alters iris configuration in pigment dispersion syndrome and in normal eyes.

PURPOSE: To examine the effect of blinking on iris configuration and aqueous humor distribution between the posterior and anterior chambers in eyes with pigment dispersion syndrome compared with healthy eyes. METHODS: High-resolution, anterior segment ultrasound biomicroscopy was performed on ten eyes of ten patients with untreated pigment dispersion syndrome and on ten control subjects. Patients were scanned continuously for 15 minutes or until the maximal change in iris configuration occurred. During this time, the eyelids were held open mechanically, and blinking was prevented. Eyes then were rescanned immediately after blinking. RESULTS: Initial iris configuration was concave in all eyes with pigment dispersion syndrome, whereas in control eyes it was concave in four eyes, planar in four eyes, and convex in two eyes. Iridozonular contact occurred in eyes with pigment dispersion syndrome only. Iridolenticular contact was greater in eyes with pigment dispersion syndrome than in control eyes. Analysis of covariance controlling for age, sex, and refractive error showed pigment dispersion syndrome to be a significant predictor of increased iris concavity. During continuous scanning, the mean change in iris position, from most concave to most convex, and mean time to the maximal change in iris configuration were greater for eyes with pigment dispersion syndrome than in control eyes and were related to the degree of initial iris concavity only (analysis of covariance). In six eyes with pigment dispersion syndrome, the eye cup was removed, normal blinking was permitted, and the eye was rescanned. The iris resumed a concave configuration in all eyes. CONCLUSION: Increased iris concavity in pigment dispersion syndrome appears to be related to increased iridolenticular contact. This creates an anatomic configuration that predisposes to reverse pupillary block. The accumulation of aqueous humor in the posterior chamber, when blinking is prevented, alters iris position in pigment dispersion syndrome and in healthy eyes and increases iridozonular and iridociliary-process distances while minimizing iridolenticular contact. Normal blinking appears to create transient vector forces which promote aqueous humor flow from the posterior to anterior chamber.

Adult↗
PubMed1995

High prospective fetal loss rate in untreated pregnancies of women with recurrent miscarriage and antiphospholipid antibodies.

Antiphospholipid antibodies (APA), lupus anticoagulant (LA) and/or anticardiolipin antibodies (ACA), are associated with thrombosis and recurrent miscarriage. We studied the outcome of 20 pregnancies in women (median age 32 years; range 23-41) with APA (14 LA positive; three immunoglobulin (Ig) G ACA positive; two IgM ACA positive and one LA and IgG ACA positive) and history of recurrent miscarriage (median 4; range 3-11) who declined pharmacological treatment in their next pregnancy. Comparison was made with a cohort of 100 consecutive women (median age 33 years; range 23-44) with recurrent miscarriage (median 4; range 3-10), in whom no underlying cause to account for their pregnancy losses was found. Of the 20 women with APA, 18 (90%) miscarried compared to 34 of the 100 women (34%) with normal investigations (P < 0.001). The majority (94%) of miscarriages in women with APA occurred in the first trimester. Fetal heart activity was seen prior to fetal death in 86% of women with APA compared to 43% of women with normal investigations (P < 0.01). The first trimester loss of embryonic pregnancies is the most common type of miscarriage in women with APA. This may be a result of defective implantation and subsequent placentation.

Abortion, Habitual↗
PubMed1995

Antiphospholipid antibodies and beta 2-glycoprotein-I in 500 women with recurrent miscarriage: results of a comprehensive screening approach.

Five hundred consecutive women (median age 33 years; range 19-45) with a history of recurrent miscarriage (median 4; range 3-16) were screened for the presence of antiphospholipid antibodies (APA)-lupus anticoagulant (LA) and/or anticardiolipin antibodies (ACA). The prevalence of persistently positive tests for LA was 9.6% and for immunoglobulin G (IgG) and immunoglobulin M (IgM) ACA was 3.3 and 2.2% respectively. Only seven women (1.4%) were LA and ACA positive. Repeat testing, after an interval of at least 8 weeks, demonstrated that only 65.7% of LA positive, 36.6% IgG ACA positive and 36.0% IgM ACA positive women on initial testing had a second positive test result. The dilute Russell's viper venom time detected the LA significantly more often than either the activated partial thromboplastin time or the kaolin clotting time (P < 0.001). There was no difference in the gestation of previous miscarriages between APA positive and APA negative women. There was no difference in the plasma beta 2-glycoprotein-I concentrations between APA positive and APA negative women with miscarriages and normal women. All women with a history of recurrent miscarriage should be tested for the presence of both LA and ACA. A second confirmatory test should be performed in those with an initial positive test result.

Abortion, Habitual↗
PubMed1995

Optimal management of the pancreatic remnant after pancreaticoduodenectomy.

OBJECTIVE: The authors evaluated methods of operative management of the pancreatic remnant after pancreaticoduodenectomy. SUMMARY BACKGROUND DATA: Despite reductions in mortality after pancreaticoduodenectomy, leakage from the pancreatic remnant still may cause significant morbidity. Patients with small, unobstructed pancreatic ducts or soft, friable pancreata are at particularly high risk. Although numerous surgical techniques have been described to avoid such complications, no single method is suitable for all patients. METHODS: The authors retrospectively reviewed the medical records of 114 consecutive patients who underwent pancreaticoduodenectomy. Sixty-nine patients were men (61%) and 45 were women (39%), with median age 66 years. Underlying disease was malignant in 87 (76%) and benign in 27 (24%). Patients were divided into groups based on risk for postoperative pancreatic fistula and on the operative management of the pancreatic remnant. Sixty-eight patients underwent end-to-side pancreaticojejunostomy, 13 of whom were high risk (group 1A) and 55 of whom were low risk (group 1B). Thirty-seven patients, all high risk, had either pancreatic duct closure by oversewing (N = 19, group 2) or end-to-end pancreaticojejunal invagination (N = 18, group 3). Nine patients underwent total pancreatectomy (group 4). Morbidity related to prolonged pancreatic drainage (PPD) of greater than 20 days was determined. RESULTS: Overall incidence of PPD was 17% and caused the only death. Patients considered high risk for postoperative pancreatic fistula had a 36% incidence of PPD compared with 2% in patients considered low risk (p < 0.0001). Prolonged pancreatic drainage frequency related to the method of pancreatic remnant management was as follows: group 1A, 15%; group 1B, 2%; group 2, 79%; and group 3, 6% (p < 0.001 for group 2 vs. other groups). No serious sequelae followed PPD in 15 patients (79%); however, 4 patients required reoperation for pseudocyst or abscess drainage; one in group 1A (who died) and three in group 2. Multivariate analysis revealed that operative technique (oversewing of the pancreatic duct) and male sex were significant factors predisposing a patient to the development of PPD. CONCLUSION: After pancreaticoduodenectomy, pancreatic remnant management by end-to-side pancreaticojejunostomy appeared safe in low-risk patients. In high-risk patients, end-to-end pancreaticojejunal invagination was the safest option. Morbidity was greatest after pancreatic duct closure without anastomosis.

Adolescent↗
PubMed1995

Angina pectoris by Rose questionnaire does not predict cardiovascular disease in treated hypertensive patients.

OBJECTIVE: To determine the predictive value of angina pectoris diagnosed by Rose questionnaire for cardiovascular disease among treated hypertensives. METHODS: The cardiovascular experience of 4093 patients who had no history of cardiovascular disease and had been administered the Rose questionnaire for angina in a worksite treatment program was evaluated. RESULTS: Among 2659 men and 1434 women of similar age (53 versus 54 years), the race distribution was 44 versus 31% whites, 27 versus 41% blacks and 29 versus 28% Hispanics. Overall, the prevalence of angina by Rose questionnaire in women (15%) was twice that in men (7%) in all three races, with Hispanics having the highest (20 versus 10%) prevalence. Those with angina (Rose-plus) and those without (Rose-minus) had similar initial and final blood pressures. In 4.0 years of average follow-up study, the crude incidence rates (per 1000 person-years) of the recorded 120 myocardial infarctions and 35 strokes did not differ significantly between Rose-plus and Rose-minus patients, except for myocardial infarction in Hispanic men (20.5 versus 5.9). When myocardial infarction incidence was adjusted for age within each sex-race subgroup, only Rose-plus Hispanic men had a significantly greater relative risk with Rose-minus as referent (relative risk 3.13, 95% confidence interval 1.31-7.50). Overall, in the Cox proportional hazards regression model, angina by Rose questionnaire was not predictive of myocardial infarction after accounting for other recognized risk factors. CONCLUSIONS: The present data suggest that the Rose questionnaire as a diagnostic tool for angina is not predictive of subsequent clinical events among treated hypertensive patients.

Adult↗
PubMed1995

Medical students' contribution to the development of a smoke-free hospital policy in a university medical centre: a relevant learning experience.

In a research methodology course, second-year medical students conducted a survey on 'Enforcing a Smoking Ban in the Soroka Medical Center: a Survey of Hospital Employees on Facilitating Factors and Obstacles'. They defined the study objectives and design, developed the study instrument, carried out the survey, coded and entered the data into mainframe computers, analysed the computer output, and prepared oral and written reports. The aims of the project were twofold: to survey employees' attitudes to a hospital smoking ban and to train medical students in the planning and conduct of a research project on public health or preventive medicine. Twelve students conducted a cross-sectional survey of 208 hospital employees (10% of the hospital staff). Employees were surveyed regarding smoking status, interest in quitting smoking, knowledge of the law banning smoking in public places, knowledge of the health effects of passive smoking, attitudes towards a hospital smoking ban and potential obstacles to its implementation. The students rated the course as excellent. They gained important research skills, as well as practical medical and public health experience through active participation in the design and execution of a study project with public health implications. At the first meeting of the hospital committee appointed to enforce a smoke-free hospital, the students' findings were reported in full, and their recommendations have guided policy decisions.

Health Policy↗
PubMed1995

Low urinary sodium is associated with greater risk of myocardial infarction among treated hypertensive men.

A sodium-reduced diet is frequently recommended for hypertensive individuals. To determine the relationship of sodium intake to subsequent cardiovascular disease, we assessed the experience of participants in a worksite-based cohort of hypertensive subjects. The 24-hour urinary excretion of sodium (UNaV), potassium, creatinine, and plasma renin activity was measured in 2937 mildly and moderately hypertensive subjects who were unmedicated for at least 3-4 weeks. Morbidity and mortality in these systematically treated subjects were ascertained. Men and women were stratified according to sex-specific quartiles of UNaV. Subjects in these strata were similar in race, cardiovascular status, and pretreatment and intreatment blood pressure. Subjects with lower UNaV were thinner, excreted less potassium, and had higher plasma renin activity. During an average 3.8 years of follow-up, a total of 55 myocardial infarctions occurred. Myocardial infarction and UNaV were inversely associated in the total population and in men but not in women, who sustained only nine events. In men, age- and race-adjusted myocardial infarction incidence in the lowest versus highest UNaV quartile was 11.5 versus 2.5 (relative risk, 4.3, 95% confidence interval, 1.7-10.6). No association was observed between non-cardiovascular disease mortality (n = 11) and UNaV. There was a significant linear trend in proportions of myocardial infarction by UNaV quartile, with a break point after the lowest UNaV quartile.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Isolated diastolic hypertension. A favorable finding among young and middle-aged hypertensive subjects.

To identify pretreatment characteristics associated with subsequent myocardial infarction in young and middle-aged previously untreated hypertensive individuals, we examined the experience of 1560 participants in a work-site hypertension control program who were younger than 60 years. Subjects were categorized by initial blood pressure as having isolated diastolic hypertension (< 160/> or = 90 mm Hg, n = 965) or combined systolic and diastolic hypertension (> or = 160/> or = 90 mm Hg, n = 595). During 4.5 years of follow-up, there were 24 myocardial infarctions, yielding an overall incidence of 3.89 per 1000 person-years. Subjects with systolic/diastolic hypertension were older, had higher cholesterol and blood sugar levels, and included more smokers and people with left ventricular hypertrophy on electrocardiogram than those with isolated diastolic hypertension. Age-adjusted incidence rates for myocardial infarction were 5.20 and 2.21 per 1000 person-years in systolic/diastolic hypertension and isolated diastolic hypertension, respectively, and the relative risk of systolic/diastolic hypertension was 2.31 (95% confidence interval, 1.29-4.15). Among subjects with isolated diastolic hypertension, no myocardial infarction occurred in those with systolic pressure less than 140 mm Hg. Cox regression analysis including other known risk factors showed that pulse pressure, as a continuous variable (hazards ratio, 1.54; 95% confidence interval, 1.08-2.20), and type of hypertension, ie, systolic/diastolic hypertension versus isolated diastolic hypertension (hazards ratio, 2.11; 95% confidence interval, 1.08-4.13), were independently associated with myocardial infarction. These results suggest that young and middle-aged treated hypertensive individuals with normal pretreatment systolic pressure enjoy a more favorable prognosis than do those with systolic elevation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Enhanced interleukin-8 release and gene expression in macrophages after exposure to Mycobacterium tuberculosis and its components.

Mycobacterium tuberculosis infection is accompanied by acute and chronic inflammatory infiltrates associated with necrotizing granulomas in lung tissue. The cellular infiltrate is characterized by inflammatory cells which include neutrophils, lymphocytes, and macrophages. In animal and in vitro models of mycobacterial infection, cytokines including tumor necrosis factor-alpha (TNF-alpha), interferon gamma (IFN-gamma), and interleukin-1 beta (IL-1 beta) participate in granulomatous inflammation. We hypothesized that interleukin-3, a potent chemoattractant for neutrophils and lymphocytes, could be released by activated alveolar macrophages after exposure to M. tuberculosis or its components and contribute to granulomatous lung inflammation. A quantitative immunoassay revealed that IL-8 protein release was significantly elevated in supernatants of macrophages and in lavage fluid obtained from patients with pulmonary tuberculosis compared to normal controls. In addition, Northern blots demonstrated striking up-regulation of IL-8 mRNA in macrophages from these patients. M. tuberculosis and its cell wall components lipoarabinomannan (LAM), lipomannan (LM), and phosphoinositolmannoside (PIM) stimulated IL-8 protein release and mRNA expression in vitro from alveolar macrophages, but deacylated LAM did not. Neutralizing antibodies to TNF-alpha and/or IL-1-alpha and beta blocked 83% of the stimulation. IL-8 synthesis and release is an early response of macrophages after phagocytosis of M. tuberculosis. Its production serves to attract both acute and chronic inflammatory cells of active infection and thus participates in the process of containment of the pathogen.

Adult↗
PubMed1995

Occupation and visual/vestibular interaction in vestibular rehabilitation.

Otolaryngologists often prescribe head movement exercise programs for patients with vestibular disorders, although the effectiveness of these programs and the critical features of the exercises are poorly understood. Because many patients who dislike exercising do not follow through with their exercises, alternatives to the traditional repetitive exercises would be useful. Subjects diagnosed with vestibular disorders were treated for 6 weeks with either an outpatient exercise program that incorporated interesting, purposeful activities or a simple home program of head movements, comparable with the exercises otolaryngologists often give their patients when they do not refer to rehabilitation. Both treatments incorporated repetitive head movements in all planes in space, graduated in size and speed. Subjects were all tested before and after treatment with standard measures of vestibulo-ocular reflex and balance, level of vertigo, gross motor skills, and self-care independence. Subjects in both groups improved significantly on the functional measures, with slightly greater improvements in the occupational therapy group. The results were maintained 3 months after the cessation of intervention. These data suggest that graded purposeful activities are a useful alternative for treating this patient population and that the essential factor in any exercise program is the use of repetitive head movements.

Adult↗
PubMed1995

Absence of steroid biosynthetic defects in heterozygote individuals for classic 11 beta-hydroxylase deficiency due to a R448H mutation in the CYP11B1 gene.

Steroid 11 beta-hydroxylase deficiency (failure to convert 11-deoxy-cortisol to cortisol) is responsible for less than 5% of cases of classic congenital adrenal hyperplasia, but it is relatively frequent in Israel, among Jews of Moroccan origin. Affected individuals have a single base substitution in exon 8 of CYP11B1 gene, codon 448, from CGC (arginine) to CAC (histidine) (R448H), a mutation that abolishes enzyme activity completely. We studied the hormonal response to ACTH stimulation in individuals genotyped to have the R448H mutation in one allele only (heterozygotes), and who were therefore assumed to have 50% of 11 beta-hydroxylase activity. No demonstrable hormonal abnormalities were found in the 6 adults (3 mothers and 3 fathers) and 2 sons studied, suggesting that a quantitatively reduced 11 beta-hydroxylase is still enough for normal adrenal biosynthesis.

Adrenal Hyperplasia, Congenital↗
PubMed1995

Stereotactic ventrolateral thalamotomy: is ventriculography necessary?

In the computed tomography/magnetic resonance imaging (CT/MRI) era, the need for ventriculography to perform ventrolateral thalamotomy accurately has been debated. We retrospectively compared CT/MRI-derived coordinates for ventrolateral thalamotomy with the final lesion coordinates that were determined by ventriculography and microelectrode recording in 74 thalamotomies performed from 1984 to 1994. The median three-dimensional distance between the CT/MRI-derived loci and the ventriculography/microelectrode loci was 4.7 mm (range, 1.0-11.7 mm). The techniques correlated least along the Y axis (median, -0.3 mm; range, -8.2 to 8.0 mm). Correlation along the X axis was most consistent (median, 0.5 mm; range, -4.2 to 5.0 mm). Since 1990, the CT/MRI-derived coordinates have been generated by a multimodality correlative imaging technique (MCIT). A comparison of thalamotomies performed with and without the MCIT revealed a significant improvement in the correlation of CT/MRI- and ventriculography/microelectrode-derived coordinates when the MCIT was employed. The greatest improvement was noted along the Y axis where the median absolute difference was reduced from 4.0 to 1.8 mm (P = 0.0001). The result was a statistically significant reduction in the median three-dimensional distance from 5.6 to 3.7 mm (P = 0.0007). The authors conclude that thalamotomies can be safely and effectively performed without ventriculography when the MCIT is employed and supported by neurophysiological monitoring.

Adolescent↗
PubMed1995

Current treatment of normal-pressure hydrocephalus: comparison of flow-regulated and differential-pressure shunt valves.

FROM THE RECORDS of approximately 1500 shunt operations performed between 1987 and 1992, we identified 37 adults between ages 38 and 86 years (mean, 70 yr) with the normal-pressure hydrocephalus (NPH) syndrome who underwent surgery by a single surgeon. Since 1990, we have routinely used a flow-regulated shunt system (Orbis-Sigma valve [OSV]; Cordis Corporation, Miami, FL) in these patients. In this study, we compared the OSV system with conventional differential-pressure (DP) shunt systems uniformly used before 1990. This series (n = 37) consisted of 62% men (n = 23) and 38% women (n = 14). We excluded all patients with hydrocephalus associated with central nervous system neoplasms, intracerebral hemorrhage, or trauma as well those with radiographically documented late-onset aqueductal stenosis. All patients presented with the NPH clinical syndrome, chiefly with magnetic gait. In addition, 75% of patients experienced cognitive loss and 59% experienced urinary incontinence. The mean duration of preoperative symptoms was 35 months (range, 7-120 mo). Eight patients (22%) had undergone previous shunting procedures before referral to our service. A total of 89 shunt operations were performed in the 37 patients. Using actuarial methods and controlling for a history of prior shunt surgery, we found no significant difference in the time to initial malfunction (shunt survival) between the OSV and the DP shunts. There were three subdural hematomas and one infection in the OSV group compared with no complications in the DP valve group (P = 0.11). Thirty-six patients were available for follow-up, at a mean of 14 months after surgery. Nearly 90% of all patients experienced improvement in gait after shunting, regardless of the valve system that was used. There was one unrelated death. Realizing the limitations of a retrospective analysis and on the basis of the limited number of patients in this study, we conclude that using actuarial methods, we found no significant difference in shunt survival when comparing the OSV with the standard DP valve shunt systems with antisiphon devices in patients with NPH. Contrary to previous reports, the OSV is not free of overdrainage complications. Most patients (89%) with the NPH syndrome who primarily presented with gait disorder experienced significant improvement in gait after either OSV or DP shunting procedures when selected for surgery on the basis of the clinical syndrome and confirmatory radiographic data.

Adult↗