Heroin users: notifications to the Home Office Addict's Index by general practitioners.

In a study of 113 heroin users who attended a Scottish general practice of 11 doctors information was gathered retrospectively regarding notification of these patients to the Home Office. The doctors were questioned about their practices for notification. Surprisingly few of the patients had been correctly notified and renotified where appropriate, and there was great variation in the doctors'' notification practices, particularly with respect to defining addiction. General practitioners are now the largest source of notifications of controlled drug users, and the statistics issued by the Home Office must be interpreted in the light of their notification practices.     

Drug users in contact with general practice.

A group of heroin users who are in contact with a general practice in north west Edinburgh are described. The study group was younger and included more women than previous studies. These people used a large variety of drugs and mainly purchased them locally. Frequent and often prolonged abstinent periods occurred with no prescribed opiate treatment. The group had experienced a high rate of drug related medical disorders. All these points raise the possibility that opiate users who are known to general practitioners may be a distinctly different population from those who attend drug dependency clinics. The frequency of remission and the prevalence of polydrug use have profound implications for planning and evaluating an effective medical response.     

Hepatitis B in general practice: epidemiology,clinical and serological features,and control.

In an outbreak of hepatitis B virus infection in a south Wales village 31 cases were identified over 16 months. Spread of the infection was by sharing needles and by sexual contact. Twenty seven patients were known to have symptoms, of whom nine had an anicteric illness. Generally the illness was mild with no deaths, and there was only one chronic carrier. Two patients were only transiently positive for hepatitis B surface antigen. The outbreak was controlled by vigorous contact tracing and counselling. Despite an enormous increase in workload for the general practitioner and problems including disposal of contaminated needles, outbreaks of hepatitis B virus infection may adequately be treated in the community.     

Inherent intractability of the ascertainment problem for pedigree data: a general likelihood framework.

The problem of ascertainment in segregation analysis arises when families are selected for study through ascertainment of affected individuals. In this case, ascertainment must be corrected for in data analysis. However, methods for ascertainment correction are not available for many common sampling schemes, e.g., sequential sampling of extended pedigrees (except in the case of "single" selection). Concerns about whether ascertainment correction is even required for large pedigrees, about whether and how multiple probands in the same pedigree can be taken into account properly, and about how to apply sequential sampling strategies have occupied many investigators in recent years. We address these concerns by reconsidering a central issue, namely, how to handle pedigree structure (including size). We introduce a new distinction, between sampling in such a way that observed pedigree structure does not depend on which pedigree members are probands (proband-independent [PI] sampling) and sampling in such a way that observed pedigree structure does depend on who are the probands (proband-dependent [PD] sampling). This distinction corresponds roughly (but not exactly) to the distinction between fixed-structure and sequential sampling. We show that conditioning on observed pedigree structure in ascertained data sets obtained under PD sampling is not in general correct (with the exception of "single" selection), while PI sampling of pedigree structures larger than simple sibships is generally not possible. Yet, in practice one has little choice but to condition on observed pedigree structure. We conclude that the problem of genetic modeling in ascertained data sets is, in most situations, literally intractable. We recommend that future efforts focus on the development of robust approximate approaches to the problem.