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Biomedical subjects

D Levy

Publications and source records attributed to D Levy.

At least 343 records · Page 19Linked to original sources
PubMed1988

Tritium labeling of a powerful methylphosphonate inhibitor of cholinesterase: synthesis and biological applications.

7-(Methylethoxy phosphinyloxy)-1-methyl-quinolinium iodide (MEPQ), a powerful anti-cholinesterase methylphosphonate ester, was labeled with tritium (9 Ci/mmol) at the methylphosphonyl moiety (TCH2P(O)(OR)X) by an iodine-tritium replacement reaction. Kinetic measurements of the rate of inhibition of acetylcholinesterase (AChE) by [3H]MEPQ and its rate of hydrolysis in alkaline solution confirmed the identity of [3H]MEPQ with authentic MEPQ, which was prepared by the same reaction sequences. Gel-filtration experiments verified the radiospecificity of [3H]MEPQ. In vitro radiolabeling of both AChE and butyrylcholinesterase along with the whole-body autoradiography of [3H]MEPQ-treated mice suggests that [3H]MEPQ is a convenient marker for studying biological systems containing these esterases.

Acetylcholinesterase↗
PubMed1988

Cardiovascular risks: new insights from Framingham.

Although cardiovascular disease remains the leading cause of death in the United States, its incidence has decreased steadily during the past 20 years. This trend is largely attributable to improved detection and management of cardiovascular risk factors. The pioneering work of the Framingham Heart Study, which has followed subjects since the late 1940s, has helped shed light on the risks conferred by factors such as advancing age, hypertension, smoking, elevated serum cholesterol, diabetes, left ventricular hypertrophy, and obesity. As a result of this ongoing investigation, clinicians have gained a better understanding of the ways in which cardiovascular risks can be modified so that mortality rates will hopefully continue to decline.

Age Factors↗
PubMed1988

Silent myocardial ischemia in asymptomatic survivors of unrecognized myocardial infarction and matched controls.

Although silent myocardial ischemia (SI) occurs frequently in patients with angina and is of prognostic significance, little is known of its occurrence in other subgroups. We assessed the incidence of SI in offspring of Framingham Heart Study (FHS) patients following unrecognized myocardial infarction (UMI) and in controls without MI but who were matched for age, sex, hypertension, diabetes, smoking, and total cholesterol at entry into the FHS. Of the 20 UMI patients, six had died and one with left bundle branch block was excluded. The remaining 13 UMI patients and 26 control patients underwent 24-hour ambulatory electrocardiographic monitoring (AECG) for SI. Two patients (one from each group) with angina were excluded from the AECG analysis. Only two (15.4%) of the UMI patients and two (7.7%) of the control patients had any AECG evidence of SI. These preliminary results suggest that routine monitoring for SI is not indicated in asymptomatic long-term survivors of UMI or in asymptomatic patients without prior MI but with otherwise similar risk profiles.

Adult↗
PubMed1988

Extraction of the third molar and patient satisfaction.

Patient satisfaction is an important outcome measure of health care. This study was designed to evaluate patient satisfaction with extraction of the third molar in relation to certain criteria involving structure, process, and outcome. A 16-item patient-satisfaction questionnaire was developed and mailed to 262 patients who had third molars extracted in a university-based clinical department during an 18-month period. The returned questionnaires were subjected to a factor analysis by means of the varimax method; the analysis yielded three "clusters" that we labeled "general satisfaction," "interpersonal satisfaction," and "satisfaction with cost." Two-tailed Student's t tests were used to relate the clinical data to each area of satisfaction. There were a total of six statistically significant interactions in the data matrix at the 0.05 level. Three of these pertained to general satisfaction and three to interpersonal satisfaction. The methods used in this study can be used to relate components of patient satisfaction to elements of dental care.

Consumer Behavior↗
PubMed1988

The collaborative study of the international standard of dog, Canis domesticus, hair/dander extract.

A collaborative study was carried out to assess the suitability of a chosen preparation to serve as the international standard (IS) for dog (Canis domesticus) hair/dander extract. Sets of five coded preparations of dog extract, including the proposed IS, were delivered to each participating laboratory in glass-sealed ampules. Fifteen laboratories in nine different countries examined the preparations by RAST inhibition, crossed immunoelectrophoresis/crossed radioimmunoelectrophoresis, histamine release, and by other methods. In spite of the use of different versions of methods and different reagents, quite consistent results were obtained, and the proposed IS was found to have a satisfactory activity in all assays and to be useful as a calibrator when allergenic potency of similar dog allergenic extracts was estimated. Four laboratories estimated the specific content of allergens Ag 3, Ag 13, and albumin and found the proposed IS to be a suitable standard for these assays. On the basis of the results from this study, the World Health Organization established the preparation as the international standard for dog hair/dander extract with an assigned unitage of 100,000 IU per ampule. The units refer to both the total allergenic activity of the ampule and to that of individual allergens.

Allergens↗
PubMed1988

Increased REM sleep in rats selectively bred for cholinergic hyperactivity.

We have examined the sleep profile of the Flinders Sensitive Line (FSL) of rats, which were selectively bred for supersensitive responsivity to an acetylcholinesterase inhibitor (DFP). These animals have an increased density of muscarinic receptors in striatum and hippocampus and display a number of behavioral and neuroendocrine characteristics that may represent a rodent analogue of clinical depression. A continuous 48-hour sleep EEG recording was obtained. Compared to control rats (the Flinders Resistant Line), the FSL rats had selectively more rapid-eye-movement (REM) sleep as a percentage of total sleep time. In addition, the REM sleep latency was significantly shorter and the REM-REM cycle length was significantly faster in the FSL than in the FRL strain. The two strains did not differ in total sleep time, drowsy sleep, or slow-wave sleep. The increased REM sleep in the FSL rats is consistent with the amassed evidence that cholinergic mechanisms selectively promote REM sleep, and suggests that the FSL rats may be useful in understanding the mechanism responsible for short REM latency in depression and narcolepsy.

Animals↗
PubMed1988

Immortalization of precursor cells from the mammalian CNS.

Recent studies show that the nervous system contains many molecularly distinct cell types. Clonal cell marking experiments demonstrate that different cell types in some areas of the CNS are products of a multipotential stem cell. The factors controlling the differentiation of vertebrate CNS precursor cells would be more accessible to molecular analysis if cell lines with precursor properties could be established. Here we show that cell lines expressing an antigenic marker specific for a major brain precursor cell population can be established from rat cerebellum. We demonstrate that cell lines express the precursor, neuronal or glial properties depending on the growth conditions. This work supports the view that brain precursor cells expressing the marker Rat 401 are multipotential and can differentiate into cells with either neuronal or glial properties. Cell lines capable of differentiation should be useful in defining the signaling systems generating the cell types of the brain.

Animals↗
PubMed1988

Expectations, information, and migration: the case of the West Bank and Gaza.

"This study evaluates the determinants of Palestinian migration from the West Bank and Gaza. Data are employed for the post-1967 period of Israeli rule to specify and test competing models as well as the strucure of expectations in the migration decision. Results of the analysis support a simple static expectation formulation, as is consistent with much of the short-term, low mobility cost migration between the West Bank and Jordan. Findings further point to the importance of various Israeli-Palestinian economic and political economic interactions in the determination of this controversial movement of population, including those associated with employment opportunity for Palestinian labour in Israel, elements of Israeli West Bank settlement policy and changes in local standard of living. Various policy implications of the research are indicated."

Asia↗
PubMed1988

Transcription of interferon-stimulated genes is induced by adenovirus particles but is suppressed by E1A gene products.

Interferon treatment of cell cultures results in the rapid transcriptional induction of a specific set of genes. In this paper we explore the effect of cellular infection by several adenoviruses, both wild type and mutant, on the expression of these genes. Infection with adenovirus induces the transcription of the interferon-stimulated genes in the absence of any protein synthesis. In fact, the inhibition of protein synthesis during a wild-type infection produces enhanced stimulation of transcription of these genes. Experiments with viral mutants indicate the ability to specifically suppress this transcription maps to the E1A gene. In addition, the E1A gene products are capable of suppressing the specific transcriptional induction of interferon-stimulated promoters during cotransfection experiments and therefore presumably during viral infection. The dual effect of adenovirus on the expression of interferon-stimulated genes may represent an example of action and evolutionary reaction between virus and host.

Adenovirus Early Proteins↗
PubMed1988

Neonatal brain: color Doppler imaging. Part I. Technique and vascular anatomy.

Color Doppler imaging (CDI) can demonstrate the relative direction and velocity of blood flow in color, superimposed on a conventional gray-scale ultrasound image that depicts stationary tissue. Twenty-five infants were studied with portable CDI in the coronal, sagittal, and axial planes. Bilateral antegrade flow was noted in the anterior, middle, and posterior cerebral arteries in all patients. Multiplanar CDI can image flow in the circle of Willis and its tributaries and branches.

Arteries↗
PubMed1988

Left ventricular hypertrophy. Epidemiological insights from the Framingham Heart Study.

Left ventricular hypertrophy (LVH) has assumed an important role in clinical medicine as a result of the clinical implications of this often asymptomatic finding. Epidemiological data from the Framingham Heart Study have permitted an examination of prevalence, incidence, underlying predisposing factors and prognosis of LVH. Although LVH is an infrequent finding on the electrocardiogram, it is a forerunner of coronary disease, congestive heart failure, stroke and even peripheral arterial disease. Despite being strongly related to hypertension, LVH remains associated with excess risk for adverse cardiovascular morbid and fatal outcomes, even after adjusting for blood pressure. The risks associated with LVH are comparable with those of myocardial infarction. The recent introduction of echocardiography at the Framingham Heart Study has permitted the development of new criteria for LVH based on M-mode determined left ventricular mass. Unlike its electrocardiographic counterpart, echocardiographically determined LVH is a common finding, occurring in over 15% of the general population. Echocardiographic LVH is related to hypertension, obesity, valvular heart disease, coronary disease and advancing age. Ambulatory ECG results in subjects with echocardiographic LVH demonstrate increased risk for ventricular arrhythmias, which have been shown in other clinical settings to predict risk for sudden cardiac death. Preliminary data from Framingham and elsewhere suggest that echocardiographic LVH is associated with increased risk for cardiovascular disease morbidity and all-cause mortality.

Cardiomegaly↗
PubMed1988

Echocardiographically detected left ventricular hypertrophy: prevalence and risk factors. The Framingham Heart Study.

The prevalence of and risk factors associated with echocardiographically determined left ventricular hypertrophy were examined in 4976 participants in the Framingham Heart Study (age, 17 to 90 years). Left ventricular hypertrophy was detected in 356 men (16%) and 513 women (19%). Prevalence increases dramatically with age (P less than 0.001), with 33% of men and 49% of women age 70 or older affected. A significant association between blood pressure and left ventricular hypertrophy is present and occurs at levels of systolic pressure below 140 mm Hg (age adjusted, P less than 0.001). There is a ninefold (women) to tenfold (men) increase from leanest to most obese group (age adjusted, P less than 0.001). In multivariate analysis, age, blood pressure, obesity, valve disease, and myocardial infarction are independently associated in both sexes. We conclude that left ventricular hypertrophy is a common echocardiographic finding for which several risk factors can be identified. These findings support weight reduction and blood pressure control for prevention or regression of this condition.

Adult↗
PubMed1988

T-B cell cooperation for bovine leukemia virus expression in ovine lymphocytes.

Bovine leukemia virus (BLV) replication in B lymphocytes from experimentally infected sheep depends on three conditions. First, viral production is detected only when the infected animals exhibit blood lymphocytosis. Second, it requires in vitro cultivation but is never observed in vivo. Third, enhancement of virus expression after phytohemaglutinin (PHA) or concavalin A stimulation is observed in lymphocyte cultures for all infected animals, whereas specifically B cell mitogens are inefficient. The PHA effect is linked to the presence of T lymphocytes. In addition, the conditioned medium prepared from PHA-stimulated normal lymphocytes greatly enhances BLV production. Altogether, these results establish that T lymphocytes, through a lymphokine production, are important and may be essential for BLV growth in B lymphocytes.

Animals↗
PubMed1987

Population implications of electrocardiographic left ventricular hypertrophy.

Left ventricular (LV) hypertrophy on the electrocardiogram is an ominous harbinger of cardiovascular disease in the general population markedly increasing the risk of coronary heart disease, cardiac failure, stroke and peripheral arterial disease. This contribution to risk exceeds that of the often accompanying hypertension. Once overt coronary disease occurs, electrocardiographic LV hypertrophy also further escalates risk of cardiovascular morbidity and mortality. The risk associated with electrocardiographic LV hypertrophy is particularly great when repolarization abnormality is present. Electrocardiographic LV hypertrophy and silent electrocardiographic myocardial infarction are similar in evolution and prognosis. LV hypertrophy is an important predictor of risk of cardiac failure; the electrocardiographic manifestation of LV hypertrophy predisposes to cardiac failure more than x-ray cardiac enlargement. Electrocardiographic LV hypertrophy heralds the onset of serious cardiovascular disease and premature mortality despite lack of associated symptoms. The serious prognosis of this abnormality warrants vigorous preventive management. More prospective data are needed comparing the prognosis of echocardiographic anatomical hypertrophy with that diagnosed by electrocardiography.

Adult↗