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Biomedical subjects

E Karam

Publications and source records attributed to E Karam.

13 recordsLinked to original sources
PubMed2000

Use and abuse of licit and illicit substances: prevalence and risk factors among students in Lebanon.

OBJECTIVE: This study aims at examining the patterns of 'substance' use in Lebanon among an 'at risk' population, the university students. METHOD: A stratified cluster sample of 1,851 students from two major universities was included in the study and the Diagnostic Interview Schedule (version 3) was administered. RESULTS: The prevalence of nicotine users in the sample was 18.3% and of ever consuming alcohol 49.4%. 2.1% of the sample were alcohol abusers and 2.4% alcohol dependents according to DSM-III criteria. For the remaining substances, tranquilizers were found to have the highest rate of ever use (10.2%), whereas heroin had the lowest rate (0.4%); the rates of abuse and dependence in these categories (other than alcohol and nicotine) following DSM-III criteria ranged from 0.1 to 0.8%. CONCLUSION: University students in Lebanon in this study have relatively low rates of use and abuse of substances but this might be changing.

Adolescent↗
PubMed1999

Optociliary veins in optic nerve sheath meningioma. Indocyanine green videoangiography findings.

OBJECTIVE: To report the indocyanine green videoangiography (ICG-V) characteristics of optociliary veins (OV) in optic nerve sheath meningioma (ONSM). DESIGN: Case series. PARTICIPANTS: Four eyes (patients) with OV and ONSM were examined. INTERVENTION: Indocyanine green videoangiography and intravenous fluorescein angiography (IVFA) were prospectively performed. MAIN OUTCOME MEASURES: The course of OV in ONSM cases was observed with ICG-V and IVFA. RESULTS: On ICG-V, the course of OV was followed from their origin at small tributaries of the central retinal vein, their junction with choroidal veins, and finally to their drainage in the vortex venous system. The authors found an inverse relationship between the degree of optic disc edema and the development and ease of visualization of the optociliary veins and their draining course through the choroidal circulation. The mean time from the injection of indocyanine green to the visualization of OV's draining choroidal vessels was 35.4 seconds (range, 25.4-50 seconds). Intravenous fluorescein angiography allowed visualization of OV only at the margins of the optic disc in all cases. CONCLUSION: Indocyanine green videoangiography provides important and new information in cases with OV and ONSM that is not obtained with IVFA. Such information may provide important knowledge regarding the hemodynamics of the choroidal circulation in normal and pathologic states.

Adult↗
PubMed1998

Mental health services and research in the Arab world.

Although there are 22 Arab countries in the Arab League, the mental health services provided in those countries show several forms of variation. Economic, political, social and cultural factors seem to play a major role in determining the state of the psychiatric profession and the access of the service to citizens. The different needs expressed by Arab colleagues at times seem incompatible with the available allocated resources. Some Arab countries enjoy the highest income per capita, yet this is inconsistent with the quality of mental health services available there. The per capita mental health services, the availability of a Mental Health Act, and the space allocated for mental health in medical curricula are but a few of the concerns that have been expressed by colleagues from the different countries of the Arab region. The following review will attempt to draw up a profile of the situation for mental health services and research in the region, and to suggest some measures for intervention.

Delivery of Health Care↗
PubMed1997

Transforming growth factor beta-induced phosphorylation of Smad3 is required for growth inhibition and transcriptional induction in epithelial cells.

Drosophila Mad proteins are intracellular signal transducers of decapentaplegic (dpp), the Drosophila transforming growth factor beta (TGF-beta)/bone morphogenic protein (BMP) homolog. Studies in which the mammalian Smad homologs were transiently overexpressed in cultured cells have implicated Smad2 in TGF-beta signaling, but the physiological relevance of the Smad3 protein in signaling by TGF-beta receptors has not been established. Here we stably expressed Smad proteins at controlled levels in epithelial cells using a novel approach that combines highly efficient retroviral gene transfer and quantitative cell sorting. We show that upon TGF-beta treatment Smad3 becomes rapidly phosphorylated at the SSVS motif at its very C terminus. Either attachment of an epitope tag to the C terminus or replacement of these three serine residues with alanine abolishes TGF-beta-induced Smad3 phosphorylation; these proteins act in a dominant-negative fashion to block the antiproliferative effect of TGF-beta in mink lung epithelial cells. A Smad3 protein in which the three C-terminal serines have been replaced by aspartic acids is also a dominant inhibitor of TGF-beta signaling, but can activate plasminogen activator inhibitor 1 (PAI-1) transcription in a ligand-independent fashion when its nuclear localization is forced by transient overexpression. Phosphorylation of the three C-terminal serine residues of Smad3 by an activated TGF-beta receptor complex is an essential step in signal transduction by TGF-beta for both inhibition of cell proliferation and activation of the PAI-1 promoter.

Amino Acid Sequence↗
PubMed1994

Premedication with Midazolam (Dormicum) compared with Promethazine, Droperidol and placebo in relieving anxiety using Beck's anxiety inventory.

In a randomized double-blind study, Midazolam (Dormicum) (7.5 mg) was compared with Promethazine (Phenergan) (25 mg), Droperidol (2.5 mg) and placebo as premedication for 98 pre-selected patients undergoing surgery. The anxiolytic effect of the above drugs was monitored by Beck's Anxiety Inventory. 83.3% of patients who received Midazolam had a decrease in their anxiety state compared to 55.6% for Promethazine, 12% for Droperidol and 25% for placebo. The study clearly proved that Midazolam is a better anxiolytic drug compared to Droperidol and Promethazine.

Adolescent↗
PubMed1993

Mechanics of the occlusive arm cuff and its application as a volume sensor.

Although a common medical instrument, the mechanical function of an occlusive arm cuff has not been fully described in an engineering sense. The occlusive arm cuff is examined here using a mathematical mechanics model and experimental measurements. Cuff stretch was modeled by a nonlinear pressure-volume function. Air compression was represented by Boyle's law. An apparatus was developed to measure pressure due to the air volume pumped into the cuff for fixed arm volume. Data were obtained for two different cuff designs, and reveal a nonlinear cuff pressure-volume relationship that could be represented accurately by the mathematical model. Calibration constants are provided for the two types of occlusive cuff. Thus, the cuff pressure was found to consist of a balance between that produced by stretch of the elastic cuff bladder and that of the compression of the air contained within the bladder. The use of the gas law alone was found to be inadequate to represent the cuff mechanics. When applying the cuff to measure change in arm volume, such as during plethysmography or oscillometry, it cannot be assumed that the cuff sensitivity is constant. More precisely, it was found that the occlusive cuff is a transducer with a volume sensitivity that increases with cuff pressure and volume until it becomes nearly constant at high levels of cuff pressure (150 mmHg). A hypothetical case of a linear elastic artery with constant pulse pressure was used as input to the cuff model to illustrate the change in cuff pressure oscillations that occurs while cuff pressure is released.(ABSTRACT TRUNCATED AT 250 WORDS)

Arm↗
PubMed1992

Cardiac adaptation of sarcomere dynamics to arterial load: a model of hypertrophy.

In the past, the dynamics of the left ventricle were studied by its response to altered venous and arterial load for a given heart. This led researchers to propose the concept of an arterioventricular match or optimal point of function. The model of this paper reverses that idea by fixing preload and afterload while computing cardiac function due to altered left ventricular size or shape, resulting from modification of the number of parallel and series sarcounits. A mathematical model of physiological hypertrophy is introduced. Series and parallel arrangements of sarcounits constitute a cylindrical model of the left ventricle. Filling occurs from a venous reservoir with constant pressure through a valve, while ejection takes place into a three-element model of the systemic arterial system through another valve. It is found that the dynamics of the myofibrils can be matched to those of the left ventricle by choosing a ventricular shape that results in a minimum in myocardial O2 consumption (MVO2) for any constant ventricular load. A unique solution for the size of the ventricle results if the rate of MVO2 is specified. The model is able to predict correctly hypertrophy due to hypoxia and due to pressure (concentric) and volume (eccentric) overloads.

Adaptation, Physiological↗
PubMed1992

[Cognitive therapy].

This paper offers an introduction to cognitive therapy which gives special importance to schemas of thinking in the expression of affect and behavior. Depression is a disease in which distorted and idiosyncratic patterns of thinking are activated; these are the major target of cognitive therapy. This therapy obeys specific laws and techniques based on scientific data and thus requires special training. The improvement of depression through cognitive therapy leads to the disappearance of depressive symptoms and the birth of adequate patterns for the management of psychic equilibrium. A plethora of publications emphasize the efficacy of cognitive therapy in the treatment of depression. This technique is in use, in Lebanon, in the Clinical and Research Service of Psychiatry and Psychology at St. Georges Hospital, Beirut.

Clinical Trials as Topic↗
PubMed1989

Physiological basis for mechanical time-variance in the heart: special consideration of non-linear function.

A relationship between ventricular pressure and volume is developed starting from basic cardiac muscle mechanics. The known and measurable properties of myocardium, such as the Hill law, the periodic excitation-contraction mechanism, and non-linear elasticity of the surrounding elastin and collagen structure, are formulated into a myofibril unit. A cylindrical geometry is chosen to represent the structure of the ventricle, using the myofibril unit as the basic building block. Pressure-volume isochrones computed from this model illustrate non-linear function in the heart which arises from both geometric effects and muscle effects. The above theory and model is linearized to provide a special study case. The behavior that resulted is that of a time-varying elastance, E(t), and, hence, can help in the interpretation of its meaning. It is found that the minimum in E(t) is the consequence of the stiffness of the myocardial fibrous network, adjusted by a geometric factor. In addition, the magnitude of E(t) is governed by myocardial contractility, a geometric factor, and the excitation-contraction mechanism, where time-dependency is imparted by periodic excitation. Since the elastic fibers are the only true elastic elements, the quantity of elastance is determined by controlled volume feedback. A circuit model is provided to illustrate this concept. The non-linear active and passive heart function curves are specified independently. These curves are required to intersect below the resting volume and result in a negative pressure at the intersection. This is found to explain the phenomenon of ventricular suction. In addition, they lead to a time-varying dead volume by virtue of time-dependent isochronal slope. Non-linear function is introduced to the model and is found to explain the variation in curvature of the ventricular isochrones.

Animals↗
PubMed1980

Hopelessness, depression, and suicide intent.

Seventy-three inpatients completed Beck's Suicide Ideator Scale, Beck's Hopelessness Scale and the MMPI Depression Scale. As hypothesized, suicide intent was significantly more correlated with hopelessness than with depression. When the effect of hopelessness was removed statistically, there was no relationship between suicide intent and depression.

Adult↗