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Biomedical subjects

J Levitan

Publications and source records attributed to J Levitan.

10 recordsLinked to original sources
PubMed2005

Statistical analysis of the DIAMOND MI study by the multipole method.

We present a new method to describe the dynamics of the beat-to-beat RR time series. The classification of the phase-space plots obtained from RR time series is performed by a calculation of parameters which describe the features of the two-dimensional plot. We demonstrate that every parameter has its specific consequence on the evaluation of the state of the cardiac function. By applying the method to the DIAMOND MI study we demonstrate that these parameters have more prognostic power than previously suggested risk markers. The results suggest that the RR intervals constitute a highly complex time series which necessitates the use of refined mathematical-statistical methods in order to reveal pathologies in the heart rate.

Double-Blind Method↗
PubMed2001

Classical nonlinearity and quantum decay: the effect of classical phase-space structures.

We investigate the decay process from a time dependent potential well in the semiclassical regime. The classical dynamics is chaotic and the decay rate shows an irregular behavior as a function of the system parameters. By studying the weak-chaos regime we are able to connect the decay irregularities to the presence of nonlinear resonances in the classical phase space. A quantitative analytical prediction that accounts for the numerical results is obtained.

Journal Article↗
PubMed2001

What parents are told after prenatal diagnosis of a sex chromosome abnormality: interview and questionnaire study.

OBJECTIVE: To investigate how the prenatal diagnosis of a sex chromosome anomaly is first communicated to parents. DESIGN: Health professionals were interviewed by telephone and the conversation was taped; parents were sent questionnaires at 1 month after diagnosis and those who responded were sent another at 6 months. PARTICIPANTS: 29 health professionals who had recently informed parents that a sex chromosome anomaly had been identified in an apparently anatomically normal, viable fetus. 23 mothers and partners who had been informed of such a diagnosis. MAIN OUTCOME MEASURES: Health professionals' knowledge about sex chromosome anomalies and parents' responses to information provided by health professionals. RESULTS: Analysis of the telephone interviews identified great variation in what different healthcare professionals know, think, and say about the same sex chromosome anomaly. The small numbers and the low response rate for the questionnaire (39% for women and 30% for men) meant that statistical analysis was not appropriate. CONCLUSIONS: It is essential for obstetric units to have an established protocol for giving results and for all staff who communicate results to parents to have accurate, up to date information about the condition identified.

Adult↗
PubMed1998

Naturalistic experience with the use of divalproex sodium on an in-patient unit for adolescent psychiatric patients.

This paper focuses on the importance of data collected not only from controlled clinical trials, but also from naturalistic treatment experience. In particular we examine the use of divalproex sodium either as monotherapy or as part of combined therapy on an in-patient ward for adolescents aged 13-18 years. All admissions in which divalproex sodium use was attempted (n=36) were analysed over a 1-year period. The most common use was in patients with a mixed-presentation bipolar disorder (n=16), followed by patients with major depression (n=7), mania (n=4) or psychoses not otherwise specified (n=4). Divalproex sodium use was evaluated in the control of mania, psychosis, agitation, mood swings, aggression and/or anxiety. Overall, the use of divalproex sodium was associated with a marked improvement along all psychopathological variables in the vast majority of patients. Few side-effects or medical complications were noted. We believe that divalproex sodium is a potentially useful drug in adolescent patients with varying forms of psychopathology.

Adolescent↗
PubMed1989

Silicone synovitis.

Silicone synovitis around a broken silicone elastomer finger joint implant was first described by Aptekar et al in 1974. More recently, it has become apparent that synovitis can result from abraded particles from intact prostheses, which can cause severe damage to adjacent bones and joints. Early recognition of this complication is important because prompt removal of the implant may be necessary to arrest a progressive, destructive process.

Aged↗
PubMed1986

Serum prolactin correlates with depressed mood during alcohol withdrawal.

Alterations in central dopamine function have been identified in depression and in alcohol withdrawal. Attempts to determine the magnitude and direction of the central dopamine alteration in alcohol withdrawal have produced conflicting results. In this study serum prolactin (PRL) was used as an indicator of central dopamine activity since dopamine is the most important factor in the control of prolactin secretion from the pituitary. Increased serum PRL levels were found during alcohol withdrawal and they correlated significantly with high scores on the Hamilton Depression Rating Scale (HDRS). No significant correlations were identified with The Brief Psychiatric Rating Scale (BPRS), the 'Mini-Mental State' of Folstein (MMS), The Beck Depression Inventory (BDI) or The Modified Gross Alcohol Withdrawal Selective Severity Assessment Scale (GAWSSA). The authors concluded that the transient depressive symptomatology typically found in detoxifying alcoholic patients may be, in part, the result of a central hypodopaminergic state.

Adult↗
PubMed1980

Sebaceous differentiation in adenoid cystic carcinoma of the parotid gland.

The first reported case of sebaceous differentiation in adenoid cystic carcinoma is presented. The tumor arose in the superficial lobe of the left parotid gland of a 48-year-old white man, had a predominantly solid histologic pattern, and manifested focal sebaceous differentiation in each of three recurrences over a two-year period. Review of the medical literature suggests that sebaceous differentiation is a normal property of some salivary ducts and may be found in any type of salivary gland neoplasm which has a ductal component. The differential diagnosis of sebaceous and clear cell lesions of salivary glands is discussed.

Ameloblastoma↗