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Biomedical subjects

C D Kaplan

Publications and source records attributed to C D Kaplan.

At least 19 recordsLinked to original sources
PubMed1995

Retinal degeneration characterizes a spinocerebellar ataxia mapping to chromosome 3p.

A heterogeneous group of neurological disorders known as the spinocerebellar ataxias (SCA) are characterized by degeneration of the cerebellum, spinal cord and brainstem. We describe linkage analysis in four unusual SCA families revealing a distinct disease locus on chromosome 3p14-21.1. The disease in these families is distinguished from other forms of SCA by concomitant retinal degeneration. Initial visual problems leading to blindness, disabling ataxia and anticipation are seen in all kindreds. The anticipation in these families suggests a dynamic mutation at this locus. Eventual molecular characterization of this disease may provide valuable insights into the processes of both neural and retinal degeneration.

Adolescent↗
PubMed1994

The prevention of stimulant misuse.

The term 'stimulant' refers to a class of drugs that increase psychophysiological arousal. From the viewpoint of prevention, it is more useful to look primarily at the social consequences and functions of stimulants. Every society has a documented use of stimulants. When planning interventions the dynamics of use must be placed in the foreground. Stimulant epidemics, like problematic stimulant users, have a natural tendency to burn themselves out. Different types of stimulants may differ in their origins, but their epidemiological consequences and use functions tend to be similar. Implications for prevention can be drawn from the characteristics of stimulant use epidemics. Users at risk for socially unacceptable patterns should be targeted for prevention efforts. Mass media campaigns that single out stimulants should be avoided. Much of the harm associated with stimulants is a consequence of life-styles characterized by polydrug use and unhealthy practices. Prevention should be timed to the appropriate period of the epidemic. Interventions useful at period 1 will not work at period 2. The recommendations of the WHO Advisory Group on the Adverse Effects of Cocaine and Coca provide a good model for primary, secondary and tertiary prevention for all forms of stimulant misuse. Stimulant prevention must be creative in finding ways of encouraging the movements of the drug to the periphery of users' lives.

Amphetamines↗
PubMed1992

Are there 'casual users' of cocaine?

Medical and public opinion about cocaine use have shifted dramatically over the past decade. New research methodologies and definitions to evaluate the impact of cocaine are needed. This paper presents a theoretical definition and empirical analysis of the 'casual user' of cocaine. Data have been drawn from a subsample of 58 cocaine users and their cocaine-using contacts in Rotterdam. The methodology of the study presents a novel approach to patterns of cocaine use involving the integration of social network variables with 'snowball' sampling data collection techniques. The theoretical definition is systematically related to two social context variables: (1) the scope of settings where contacts use cocaine; (2) the degree of involvement in social network relations of actual cocaine use. Scope of settings has been defined in terms of the number of cocaine-using social circuits contacts are drawn from: i.e. 'narrow' setting where all contacts originate from one circuit while a 'wide' setting indicates contacts come from two or more circuits. Involvement has been defined in terms of the percentage of contacts where the relation with study participants is characterized by cocaine use most or all of the time. Additional social network variables measuring the mean duration (in years) of contacts' cocaine use and the use of cocaine with contacts in the last six months are subsequently related to the scope and involvement variables. The implications of the analysis for a new cross-classification of cocaine use patterns are discussed with special reference to public health policy issues.

Analysis of Variance↗
PubMed1992

Prevalence of psychopathology in drug-addicted Dutch.

In Dutch samples of treated heroin addicts, high prevalences of a heterogeneous psychiatric co-morbidity can be found with regard to Diagnostic and Statistical Manual (third edition) (DSM-III) classifications, Zung Depression Inventory, and sum scores of a 90-item Symptom Checklist (SCL-90). A high-threshold (N = 87) and a low-threshold (N = 116) program are compared with regard to psychopathology and severity of psychopathology. A consecutive admissions design was used. More than 50% of the respondents suffered from a lifetime DSM-III Axis I disorder (70% with antisocial personality disorder included), and 40% were still suffering from one of the disorders in the year preceding the interview. Schizophrenia was diagnosed five times as much as in normal population samples (5%). The most frequently diagnosed disorders were recurrent major depression, phobic disorders, alcohol abuse and dependence, dysthymic disorder, and antisocial personality disorder. The prevalences of DSM-III disorders, the total number of symptoms, and the score on the Zung Depression Inventory and 90-item Symptom Checklist were all significantly higher in treatment-seeking drug addicts entering the high-threshold program. Within each program, three clinically meaningful subgroups can be distinguished: one group with DSM-III Axis I lifetime or current psychopathology and/or antisocial personality disorder, one with antisocial personality disorder only, and one with neither DSM-III psychopathology nor antisocial personality disorder. Possibly, self-selection results in patients with more serious conditions entering more treatment-oriented facilities. Odds ratios show that schizophrenia and mood disorders and especially associated on a lifetime and current basis.

Adult↗
PubMed1992

The effects of orally active enkephalinase inhibitors on morphine withdrawal syndrome.

Considerable evidence has accumulated to suggest that intracerebroventricular administration of enkephalinase inhibitors, which do not penetrate the blood-brain barrier, significantly attenuates opioid withdrawal syndrome. Therefore, the aim of this study was to examine the effect of intraperitoneal (i.p.) administration of orally active enkephalinase inhibitors, acetorphan (2.5-20 mg kg-1) and SCH 34826 (15-120 mg kg-1). These drugs significantly decreased the severity of the naloxone precipitated withdrawal syndrome in morphine dependent rats and mice. It therefore appears that these orally active enkephalinase inhibitors are promising tools in studying modulation of opioid dependence phenomena.

Administration, Oral↗
PubMed1992

Drug use contexts and HIV-consequences: the effect of drug policy on patterns of everyday drug use in Rotterdam and the Bronx.

Epidemiological data on HIV seroprevalence has been essential in assessing the (future) extent of the AIDS epidemic. By coupling these data with quantifiable variables related to injection drug use (frequency of injecting, number of needle sharing partners) specific 'risk behaviors' could be determined, accounting for the rapid spread of the virus in the injecting drug user (IDU) population. Yet, such data give little information on the social mechanisms and setting generating such risk behaviors. In order to understand the transmission of HIV among the IDU population one needs to study the micro settings and social context of drug use. This paper describes and explores certain patterns of drug use, sharing, and natural support systems found amongst IDUs in two very different cities, Rotterdam (The Netherlands) and the Bronx, New York City (USA). By specifying details of the micro-settings of everyday drug use in both locales, it is possible to identify certain common elements and consequences of personal and social behavior driven by drug use per se (e.g. drug preference), and to differentiate these from behaviors and consequences determined by drug policy and the social context in which drug use actually occurs. These policies and the social context they create can in turn be shown to relate to risks for HIV transmission, e.g. the increased likelihood of sharing injection equipment. A more careful ethnographic approach, taking advantage of natural experimental opportunities, comparisons and controls, may be utilized to examine drug-related behaviors in their social context and to better assess their relevance to public health--especially to AIDS.

Cross-Cultural Comparison↗
PubMed1991

Changing cocaine smoking rituals in the Dutch heroin addict population.

Recently the use patterns, circumstances and consequences of cocaine have become of interest to both researchers and policy makers in Europe. Currently only a few studies have been conducted of the social epidemiology of cocaine. In this article, focus is placed upon the use of cocaine in one subpopulation, heroin addicts. Based mainly upon ethnographic research conducted in the city of Rotterdam it can be estimated that the prevalence of cocaine use in this population has reached a very high level. The mode of ingesting cocaine parallels that of heroin; Injecting Drug Users inject cocaine-hydrochloride, heroin smokers smoke cocaine base. This cocaine base is mainly processed by users themselves. An exception to this rule of self-processing can be found in the most marginalized addicts who do not have access to the house addresses where both heroin and cocaine-hydrochloride are sold. In this group the selling of 'cooked cocaine', a crack-like product, has occurred. The circumstances and potential consequences of the emergence of 'cooked cocaine' are discussed.

Cocaine↗
PubMed1991

What works in drug abuse epidemiology in Europe.

This paper discusses what works and what does not work in drug abuse epidemiology in Europe. Given the tradition in European countries of defining the drug abuse problem in terms of social and medical interventions, epidemiological research is also tied to these interventions, and consequently to community-based research. What seems not to work, and what is generally suspect are grand legal designs to solve the drug problem. Promising initiatives are going towards a compromise between a relaxation of legal sanctions but a tendency away from legalization. What is recommended is striving towards a more analytic and multidisciplinary epidemiology that can help society critically evaluate the truth-value of its moral prerogatives.

Community Health Services↗
PubMed1991

Needle sharing in The Netherlands: an ethnographic analysis.

BACKGROUND: Needle sharing has been reported to be the main cause of the rapid spread of the human immunodeficiency virus (HIV) among injecting drug users. Risk behaviors such as needle sharing are, however, the end result of complicated interaction patterns in drug user networks, which have their specific rules and rituals, and larger social structures and official drug policy. METHODS: To study these interaction patterns we examined the drug administration rituals of heroin addicts in Rotterdam, The Netherlands. Intensive ethnographic descriptions were collected by participant observation. RESULTS: In less than 10% of the observed self-injections unsafe syringes were used. In 68% of the self-injections new, sterile syringes were used. Needle sharing as a planned sequence was not observed. Sharing was determined primarily by the availability of syringes, experience with the injecting ritual, and drug craving. In all observed needle-sharing events, subjects were aware of the risks involved and undertook efforts to clean the injection equipment. CONCLUSIONS: In contrast to psychological approaches aimed at reducing individual "risk behavior," these findings suggest that HIV prevention can be made more effective if active drug injectors are organized to help themselves and their peers prevent high-risk exchange situations.

Adult↗
PubMed1989

The Addiction Severity Index: reliability and validity in a Dutch addict population.

In order to meet the need for a multidimensional diagnostic instrument in the field of drug addiction in The Netherlands, the Addiction Severity Index (ASI) has been applied to a sample of Dutch drug addicts. In this article the usefulness and psychometric characteristics of the Dutch version of the ASI are discussed. Overall, there was no evidence of a general relationship between the ASI ratings of problem severity. The severity ratings showed good concurrent validity, and subscales of selected items in each problem area of the ASI were demonstrated to have good internal consistency reliability. Regression analysis indicated that the ASI items accounted for a considerable proportion of the variance in the severity ratings, indicating a strong relationship between "subjective" rating and "objective" data. On the basis of the general concept of the ASI and the satisfactory psychometric characteristics, implementation of the instrument in The Netherlands is advocated.

Adult↗
PubMed1988

The pleasure dome with caves of ice. Cerebral lateralization, creativity, and the drug experience.

The drug experience is not a phenomenon of isolated interest to the neurosciences. The investigation of the phases of the drug experience can tell us much about the process of stimulating and losing creativity. This paper aimed to present a human model of creativity and the drug experience to complement the existing animal models. It remains for future research to reject or confirm the hypotheses sketched here. The exploration of these hypotheses would give us better insight into the control mechanisms determining the delicate process of creating functional forms that link words and images to feelings (for example, art). The examination of the drug experience from the point of view of cerebral lateralization provides a better understanding of how the quest for art may be tied up with the consequences of self-destruction. As Luria has noted, the gnostic disturbances associated with damages of the right hemisphere are "the remarkable absence of perception of the patient of his own defects; . . . such patients have unimpaired speech but they lack the precise analysis of the direct flow of information about their own body." Perhaps this was intuitively known by Coleridge, who in 1803 had already passed into the maintenance phase and wrote the fragment "Reality's Dark Dream": I know 'tis but a dream, yet feel more anguish Than if 'twere truth. It has been often so: Must I die under it? Is no one near? Will no one hear these stifled groans and wake me?

Animals↗
PubMed1987

Temporal and social contexts of heroin-using populations. An illustration of the snowball sampling technique.

Snowball sampling is a method that has been used in the social sciences to study sensitive topics, rare traits, personal networks, and social relationships. The method involves the selection of samples utilizing "insider" knowledge and referral chains among subjects who possess common traits that are of research interest. It is especially useful in generating samples for which clinical sampling frames may be difficult to obtain or are biased in some way. In this paper, snowball samples of heroin users in two Dutch cities have been analyzed for the purpose of providing descriptions and limited inferences about the temporal and social contexts of their lifestyles. Two distinct heroin-using populations have been discovered who are distinguished by their life cycle stage. Significant contextual explanations have been found involving the passage from adolescent peer group to criminal occupation, the functioning of network "knots" and "outcroppings," and the frequency of social contact. It is suggested that the snowball sampling method may have utility in studying the temporal and social contexts of other populations of clinical interest.

Activities of Daily Living↗
PubMed1981

Lateralized differences associated with semantically varied auditory material.

EEGs were recorded from 13 subjects while they listened to four tape-recorded passages differing in semantic content. The distribution of alpha band power over the two hemispheres, measured at T3/T4, was found to show significant task-dependent shifts. More reality-oriented passages tended to be processed with greater left-hemisphere involvement, while "pleasurable" material showed significant right-hemisphere involvement. Since the differences in laterality were not related to grammatical measures of linguistic complexity, the apparent shifts were attributed to semantic differences between the tasks. Explanation of the results is made in terms of a theory of the metacontrol of cerebral processing.

Dominance, Cerebral↗