Varicella-zoster virus induces apoptosis in cell culture

peer reviewedaudience: researcherApoptosis is an active mechanism of cell death which can be initiated in response to various stimuli including virus infections. In this work, we demonstrate that lytic infection by varicella-zoster virus (VZV), a human herpesvirus, is characterized by nuclear fragmentation of DNA into oligonucleosomal fragments and by chromatin condensation. In vitro, VZV-induced cell death is actually mediated by apoptosis. The mechanisms developed by cells to protect themselves against apoptosis could be one of the parameters allowing the establishment of virus latency. In the case of VZV, which can remain latent in sensory ganglia, we have not yet identified a cellular or viral protein which could play this protective role, since the observed apoptosis mechanism seems to be independent from Bcl-2, the most frequently described inhibitor of apoptosis

Stressors and resources mediate the association of socioeconomic position with health behaviours

Peer reviewedPublisher PD

Large decline in injecting drug use in Amsterdam, 1986-1998: explanatory mechanisms and determinants of injecting transitions

OBJECTIVES—To study community wide trends in injecting prevalence and trends in injecting transitions, and determinants.
DESIGN—Open cohort study with follow up every four months (Amsterdam Cohort Study). Generalised estimating equations were used for statistical analysis.
SETTING—Amsterdam has adopted a harm reduction approach as drug policy.
PARTICIPANTS—996 drug users who were recruited from 1986 to 1998, mainly at methadone programmes, who paid 13 620 cohort visits.
MAIN RESULTS—The prevalence of injecting decreased exponentially (66% to 36% in four to six monthly periods). Selective mortality and migration could maximally explain 33% of this decline. Instead, injecting initiation linearly decreased (4.1% to 0.7% per visit), cessation exponentially increased (10.0% to 17.1%), and relapse linearly decreased (21.3% to 11.8%). Non-injecting cocaine use (mainly pre-cooked, comparable to crack) and heroin use strongly increased. Trends were not attributable to changes in the study sample.
CONCLUSIONS—Harm reduction, including large scale needle exchange programmes, does not lead to an increase in injecting drug use. The injecting decline seems mainly attributable to ecological factors (for example, drug culture and market). Prevention of injecting is possible and peer-based interventions may be effective. The consequences of the recent upsurge in crack use requires further study.


Keywords: substance abuse; surveillance; cohort studie

Needle sharing and participation in the Amsterdam Syringe Exchange program among HIV-seronegative injecting drug users

To enhance the prevention of human immunodeficiency virus infection, factors related to regular participation in the Amsterdam Syringe Exchange and the borrowing of syringes were studied in 131 HIV-seronegative injecting drug users in a 1989-90 survey. A total of 29 percent of the users reported borrowing syringes, that is injecting drugs at least once in the past 4-6 months with a needle or syringe previously used by someone else. Users at increased risk of borrowing are previous borrowers, long term moderate-to-heavy alcohol users, current cocaine injectors, and drug users without permanent housing. Regular clients of the syringe exchange, when compared with other injecting drug users, were found more often to be frequent, long term injectors. They borrowed slightly less often than other users, but this was not statistically significant, even after controlling for frequency of injecting or other potential confounders. The results suggest that, 5 years after the start of the Amsterdam Syringe Exchange, drug use characteristics govern an individual injecting drug user's choice of exchanging or not exchanging syringes. The conclusion is that it seems more important to direct additional preventive measures at injecting drug users with an increased risk of borrowing rather than at users who do not participate in the syringe exchange or who do so irregularl

HIV prevalence and risk behaviour in young drug users in Amsterdam

Objectives: To assess the HIV prevalence and risk behaviour among regular young drug users (YDU) in Amsterdam. Design: Subjects were 282 YDU (using heroin, cocaine, methadone and/or amphetamines at least 3 days/week) aged 30 years or less who participated in a cross-sectional survey in Amsterdam in 1998. Participants were recruited both directly (41%) through healthcare institutions, and indirectly (59%) by referrals from YDU already enrolled. A comparison sample of YDU from the Amsterdam Cohort Study recruited between 1985 and 1989 was used to describe trends in HIV prevalence and risk behaviour. Results: Mean age was 25 years, 22% were women, 39% had at least once injected drugs, and 22% currently injected in 1998. Cocaine was more often used regularly (70%) than heroin (42%). Of the 282 YDU, 21 (7.4%) were infected with HIV. Among those who had injected drugs, HIV prevalence was 16.2%. Among those who had never injected, the prevalence of HIV infection was 1.8%. A history of injecting declined from 83% in 1985-1989 to 56% in 1998. Compared with 1985-1989, the lack of a recent steady partner appeared to be an important risk factor for a positive HIV status among injectors in 1998, whereas borrowing of used needles/syringes was no longer a risk factor. Conclusion: The use of cocaine among YDU is very popular in Amsterdam. A strong decrease in injecting behaviour has taken place, but among those who inject, risk behaviour is still considerable, and HIV infection is still widespread. Preventative activities should be expanded, specifically among YDU. (C) 2002 Lippincott Williams Wilkin