Current Injectors Research Articles

Analysis of ground states of0−πlong Josephson junctions

We investigate analytically a long Josephson $0\ensuremath{-}\ensuremath{\pi}$ junction with several $0$ and $\ensuremath{\pi}$ facets which are comparable to the Josephson penetration length ${\ensuremath{\lambda}}_{J}.$ Such junctions can be fabricated exploiting (a) the d-wave order-parameter symmetry of cuprate superconductors; (b) the spacial oscillations of the order parameter in superconductor-insulator-ferromagnet-superconductor structures with different thicknesses of ferromagnetic layer to produce 0 or $\ensuremath{\pi}$ coupling; or (c) the structure of the corresponding sine-Gordon equations and substituting the phase $\ensuremath{\pi}$ discontinuities by the artificial current injectors. We investigate analytically the possible ground states in such a system and show that there is a critical facet length ${a}_{c},$ which separates the states with half-integer flux quanta (semifluxons) from the trivial ``flat phase state'' without magnetic flux. We analyze different branches of the bifurcation diagram, derive a system of transcendental equations which can be effectively solved to find the crossover distance ${a}_{c}$ (bifurcation point), and present the solutions for different number of facets and the edge facets length.

Hepatitis C-related discrimination in New South Wales

Hepatitis C-related discrimination was examined. Intake interviews with 606 HepCare trial participants from New South Wales were analysed to determine the prevalence and correlates of hepatitis C related discrimination. The sample was a mean age of 37 years, 54% were males, 79% reported a history of drug injecting and 35% were current injectors. Forty percent of the sample reported experiencing hepatitis C-related discrimination. Multivariate analysis revealed that current injectors, 35-44 year olds, females, those who had recently consulted a general practitioner and those who had been referred to a specialist for their hepatitis C were more likely to report discrimination than other groups. More research is required to attain a better understanding of hepatitis C-related discrimination.

Effects of drug treatment for heroin sniffers: a protective factor against moving to injection?

We explore the relationship between contact with treatment and transition to injection for heroin sniffers. Our primary research question is, does contact with treatment delay onset of injection for heroin sniffers? A stratified network-based sample was recruited from multiple communities in South Florida which were known for high drug use. Three categories of respondents were recruited based on injection outcome: long-term injectors, short-term injectors, and sniffers ( n=900). We answer our research question in two steps. First, we investigate the prevalence of drug treatment for heroin sniffers and injectors using case-control methods. The preliminary findings indicate a positive relationship between contact with treatment and injection status outcome. Second, we further examine the relationship by attempting to identify the causal factors that delay initial injection for a subgroup of current injectors using survival regression procedures. Delaying or preventing transition to injection could significantly decrease risk of HIV transmission by reducing or eliminating risky injecting behaviors. We conclude with a discussion of policy implications and suggestions for future research.

Witnessing heroin-related overdoses: the experiences of young injectors in San Francisco.

Assessment of young injectors' exposure and response to others' heroin-related overdose. Cross-sectional survey. San Francisco, CA, United States. Nine hundred and seventy-three street-recruited current injectors under 30 years old. Self-reported experiences of witnessing heroin-related overdoses from structured interviews. Seven hundred and nine of 973 (73%) had ever witnessed at least one heroin-related overdose, and 491 of 973 (50%) had witnessed an overdose in the last 12 months. Fourteen per cent of those who had witnessed an overdose in the past year reported that the outcome of the overdose was death. Emergency services were called to 52% of most recent witnessed overdoses. Cardiopulmonary resuscitation (CPR) or expired air resuscitation (EAR or 'rescue breathing') was performed in 61% of cases. Inappropriate strategies such as injection with stimulants or application of ice were rare. In 67% of cases in which emergency services were not called the witness said this was because the victim regained consciousness. In the remaining 33%, 56% stated emergency services were not called due to fear of the police. Respondents were willing to act at overdoses at which they were present, but frequently did not do so in the most efficacious manner. Fear of police was identified as the most significant barrier to the ideal first response of calling emergency services.

Attitudes of novice heroin injectors towards non-injecting routes of administration to prevent the transmission of blood borne viruses

This study aimed to investigate attitudes towards and experiences with heroin use, by means other than injecting, in the West Australian city of Perth. As part of a major study of hepatitis C, injecting and the prevention of hepatitis C, a study group of 65 current drug injectors were invited to describe their experiences with heroin chasing, smoking or snorting and to discuss their attitudes towards the suggestion that using heroin by non-injecting methods could be utilised as a prevention strategy for hepatitis C. Experience with non-injecting (smoking or chasing) for the study group was limited, with less than half having initiated heroin use by non-injecting means and none having sustained the practice. Attitudes towards the promotion of non-injecting methods were largely negative. A small proportion of the study group expressed support for using non-injecting methods for health reasons, the majority being dismissive of the idea. The major barriers from the injectors’ perspective were seen to be related to cost and drug effect. A pre-existing barrier in Australia to using non-injecting methods is the predominance of salt of heroin, which does not lend itself to chasing or smoking. The results of this investigation are discussed in terms of the barriers to the promotion of non-injecting drug use and methods by which such barriers might be overcome to encourage a cultural change from heroin injection to non-injecting means of administration.

Pumping iron, risking infection? Exposure to hepatitis C, hepatitis B and HIV among anabolic–androgenic steroid injectors in Victoria, Australia

Aims: To measure exposure to the hepatitis C and B viruses and HIV among Victorian steroid injectors and evaluate associations between exposure and risk behaviour, and report other characteristics of the study group. Design: Seroprevalence study using a convenience sample. Setting: Victoria, Australia. Participants: Current injectors of illicit anabolic steroids. Measurements: Prevalences of exposure to HIV and the hepatitis B and C viruses; associations of characteristics and behaviours with exposure; descriptive statistics for the sample. Findings: Six of 63 blood samples (9.5%) contained hepatitis C virus antibodies; 12.0% tested positive for hepatitis B core antibody; none contained anti-HIV. Hepatitis C virus exposure was associated with heroin injection, imprisonment, sharing needles to inject other drugs, number of tattoos, and hepatitis B virus exposure. No significant differences existed in the steroid-related risk behaviour of exposed and non-exposed individuals. Hepatitis B virus exposure was associated only with hepatitis C virus exposure, past imprisonment and age of first injection. Conclusions: Exposure to the hepatitis B and C viruses was detected; hepatitis C virus exposure was at much lower prevalence than normally found among other drug injectors. Factors other than steroid injecting were associated with exposure. Nonetheless, the hepatitis C-exposed reported many steroid-related and other risk behaviours which could spread the virus. Steroid injectors should not be neglected in blood-borne virus prevention efforts.

Patterns of Needle Acquisition and Sociobehavioral Correlates of Needle Exchange Program Attendance in Baltimore, Maryland, U.S.A.

Objectives: This study examined factors associated with obtaining syringes from a needle exchange program (NEP) and other safer sources in Baltimore, Maryland, U.S.A. Design and Methods: A cross-sectional face-to-face survey was administered to 741 current drug injectors recruited by snowball sampling techniques. A brief openended interview was conducted on a subsample. Results: Most (85%) participants obtained needles from street needle sellers. Only 8% obtained their needles exclusively from safer sources (NEPs, pharmacies, hospitals, or patients with diabetes). Cocaine use was associated with obtaining needles from the NEP but not from exclusively safer sources. Obtaining needles from only safer sources was associated with being female and less frequent needle sharing and shooting gallery attendance. Among HIV-seropositive participants, those who were diagnosed before the year that the NEP began were more likely to obtain needles from safer sources. Participants who sold needles reported that it was easy to make used needles appear to be unused, and some admitted to selling used syringes as new. Conclusions: Street needle sellers are an important source of needles for drug injectors, and few injectors appear able to determine whether these needles are clean. Individual sealing of diabetic syringes may reduce the risk of blood-borne infections by enabling both drug injectors and patients with diabetes to better judge the sterility of the needles they purchase.

Patterns of needle acquisition and sociobehavioral correlates of needle exchange program attendance in Baltimore, Maryland, U.S.A.

This study examined factors associated with obtaining syringes from a needle exchange program (NEP) and other safer sources in Baltimore, Maryland, U.S.A. A cross-sectional face-to-face survey was administered to 741 current drug injectors recruited by snowball sampling techniques. A brief open-ended interview was conducted on a subsample. Most (85%) participants obtained needles from street needle sellers. Only 8% obtained their needles exclusively from safer sources (NEPs, pharmacies, hospitals, or patients with diabetes). Cocaine use was associated with obtaining needles from the NEP but not from exclusively safer sources. Obtaining needles from only safer sources was associated with being female and less frequent needle sharing and shooting gallery attendance. Among HIV-seropositive participants, those who were diagnosed before the year that the NEP began were more likely to obtain needles from safer sources. Participants who sold needles reported that it was easy to make used needles appear to be unused, and some admitted to selling used syringes as new. Street needle sellers are an important source of needles for drug injectors, and few injectors appear able to determine whether these needles are clean. Individual sealing of diabetic syringes may reduce the risk of blood-borne infections by enabling both drug injectors and patients with diabetes to better judge the sterility of the needles they purchase.

Access to medical care and service utilization among injection drug users with HIV/AIDS

Access to care and optimal service utilization among 287 low income African American former and current drug injectors was examined. Results indicated suboptimal outpatient care, and no evidence of alternative use of hospital services. Participation in drug treatment and case management were associated with greater access to care and use of outpatient services, even after controlling for current drug use, gender, and insurance. AIDS and physical functioning limitation were associated with emergency room (ER) use and hospitalization. Participation in drug treatment and case management and an AIDS diagnosis were associated with optimal outpatient service use. Daily alcohol use was associated with ER as the usual facility for care. Integration of substance abuse treatment, case management, and medical services delivery may contribute to improved HIV care for this population.

Projecting severe sequelae of injection-related hepatitis C virus epidemic in the UK - Part 2

In Part 2, we illustrate how available data can be used to obtain preliminary estimates for Scotland of prevalent injection-related hepatitis C carriers and of maternally hepatitis C virus (HCV)-infected infants. Novel approaches to reducing uncertainty about the number of Scotland's HCV infected children of injector parents are discussed in brief. Three approaches, one direct and two indirect, to estimating the number of current and ever-injectors are presented for England and Wales. Diagnosed HCV infections in injectors and HCV test uptake by current injectors are combined with survey estimates for the ratio of ever-injectors to current injectors to estimate prevalent injection-related hepatitis C carriers. Household surveys give direct but potentially biased estimates of the number of current and ever-injectors. Indirect estimates make use of hepatitis C diagnoses in injectors, HCV prevalence and test-uptake by injectors, or exploit international comparisons. We comment on key reporting problems that inhibit synthesis of HCV progression studies; and suggest how to derive preliminary gender-and-age specific progression rates to liver cirrhosis for use in projections. Preliminary estimates for Scotland of prevalent injection-related hepatitis C carriers are: central estimate 39,000, inner uncertainty 16,000-59,000; of maternally hepatitis C virus (HCV)-infected infants central estimate 260, uncertainty 110-1100; and for England and Wales estimates of the number of prevalent ever-injectors are central estimate 360,000, uncertainty 240,000-835,000. Both hepatitis C prevalence in injectors and estimated numbers of current injectors are similar in Australia, and England and Wales (but not so for Scotland), Australian work on projections of severe HCV sequelae from hepatitis C infections may therefore be a suitable starting point for projections for England and Wales. Australia anticipates a doubling in the number of persons living with hepatitis C cirrhosis from 8500 in 1997 to over 17,000 in 2010. Australian projections of severe HCV sequelae used progression rates that, for simplicity, were independent of gender and of age at HCV infection. Faster HCV progression for males, and their higher injector prevalence, means that the impact of HCV infection on, for example, liver cancer may be evident to a greater extent and earlier in males.

Projecting severe sequelae of injection-related hepatitis C virus epidemic in the UK - Part 1

Hepatitis C is transmitted by transfusion of unscreened blood, through injecting drugs, from mother-to-child and, on occasion, sexually. Transmission generally requires that the infector is hepatitis C virus (HCV) RNA positive, a 'carrier'. About three-quarters of injectors who are hepatitis C antibody positive are HCV-RNA positive and so infectious to others. Incubation periods from HCV infection to cirrhosis and hepatocellular carcinoma are even longer than from HIV infection to AIDS, being counted in decades; they depend on age, gender, alcohol consumption and co-infection with other viruses. We identify 25 data sources that are available, or required, for projecting the severe sequelae of the injection-related hepatitis C epidemic. Three data sources relate to hepatitis C diagnosis: register of confirmed HCV infections (with initial of first name + soundex of surname + date of birth + gender = master index, exposure category, year of starting to inject, and region); surveys of HCV test-uptake by injectors and others; documentation of pregnancy and its outcome in HCV-infected women (injectors and others). Four data sources relate to HCV prevalence and incidence among injectors and others: anonymous testing for HCV antibodies in blood or saliva (for sentinel groups ranging from new blood donors, pregnant women, patients awaiting kidney transplantation, non-injector prisoners, health-care workers, non-injector heterosexuals attending genitourinary medicine clinics; to injectors in the community, at drug treatment centres or in prison); historical data on HCV prevalence in injectors; HCV incidence studies in injectors; and uptake of harm reduction measures--frequency of sharing and methadone substitution--by injectors. Key reporting problems in HCV incidence studies, which inhibit checks on the convenient exponential assumption for time from start of injecting to hepatitis C infection, are discussed. Nine critical data sources are identified for monitoring the late sequelae of hepatitis C carriage, its investigation and treatment: linkage surveillance, for example by master index, to identify deaths, hospitalisations or cancer registrations among confirmed HCV infections; surveys of HCV status among patients who undergo liver biopsy, are newly diagnosed with cirrhosis or are newly diagnosed with liver cancer; surveys of liver-biopsy rate in HCV-infected injectors and others; uptake and outcome of interferon + ribavirin in the treatment of hepatitis C carriers; cohort studies of HCV progression; sample surveys of genotype in HCV-infected injectors, and others; acute hepatitis B infections and uptake of hepatitis B immunisation by injectors; liver transplantation in HCV-infected patients; and hepatitis C-status and other risk factors in deaths from cirrhosis or liver cancer, to determine whether they are HCV and injector-related. Finally, nine critical data sources are identified for quantitative understanding of the underlying injector epidemic: drug misuse databases plus capture-recapture methods to assess number of injectors, drug-related deaths by region to assess injector numbers; number of HIV-infected injectors; HIV progression in injectors; overdose and other causes of death in injectors; expert opinion on injector incidence historically, plus survey information on age-distribution at initiation and duration of injector careers; injector incidence historically inferred from hepatitis C infected blood donors; age-distribution of current injectors and at initiation, as a check on the assumptions made in stochastic simulation about injector incidence and 'outcidence' from injecting historically; mortality of former injectors; and general population or other survey ratios of surviving ever-injectors to injectors in the last 5 years, last year and currently, as a check on simulations. We recommend a common HCV diagnosis report form to improve ascertainment of risk-factor information, especially year of starting to inject--which is a key date epidemiologically. We also recommend updated surveys of current and former injectors' HCV-test uptake, or a denominator study that registers master index and risk factor information for all HCV testees. We recommend that injector surveys ask about typical frequency of needle sharing per 4 weeks in three distinct periods this year, last year and in the first year of injecting. We also recommend the location of stored historical samples from injectors to be tested retrospectively and anonymously for HCV antibodies. We recommend immediate attention to the uptake of, and response to, combination treatment by hepatitis C carriers who are former or recovering injectors. We rec

Peer education has no significant impact on HIV risk behaviours among gay men in London.

Peer education has no significant impact on HIV risk behaviours among gay men in London.

Drug-using men who have sex with men: Sexual behaviours and sexual identities

Men who have sex with men (MSM) and use drugs are at high risk for H V. This study assessed drug and sex-related risk behaviours and sexual identities for MSMIdrug injectors and crack smokers. One hundred and forty four MSM drug injectors and crack smokers from five USA cities were interviewed. One-third of the men were current injectors, twice as many reported lifetime injection. Most (56%) reported sex with women in the prior year; sex trading was reported by 32% with males and 53% with females. There were significant differences between private and public sexual identities. For example, while 31% reported being behaviourally bisexual, only 17% identified themselves to others as bisexual. Drug using MSM are clearly a heterogenous group and prevention messages addressing this diversity are needed.

Neural responses associated with cue evoked emotional states and heroin in opiate addicts

Ten male opiate addicts, who were current heroin injectors, underwent positron emission tomographic (PET) scanning during exposure to a sequence of six alternating drug related and neutral video cues, on two occasions. After the second scan, each subject received heroin or placebo using a randomised single-blind procedure. This design allowed the investigation of patterns of brain activity during a range of self-reported cue evoked emotional states, both in the presence and absence of heroin. Self-reports of ‘urge to use’ correlated strongly with increased regional blood flow (rCBF) in the inferior frontal and orbitofrontal cortex target regions of the mesolimbic dopaminergic system, implicated in conditioning and reward. ‘Urge to use’ was also associated with highly significant increased rCBF in the right pre-cuneus, an area associated with episodic memory retrieval, and in the left insula, implicated in the processing of the emotional components of stimuli. Self-reports of feeling ‘high’ correlated with rCBF activation in the hippocampus, an area relevant to the acquisition of stimulus-associated reinforcement.

High current injectors for heavy ion driven inertial fusion

Conceptual heavy ion driven inertial fusion (HIF) drivers typically have an array of up to 100 parallel beams each supplying a beam current of ≈0.25 A. According to space-charge limitations in beam extraction and in the low energy beam transport section, there are two options in building injectors for HIF drivers. The traditional way is to use low current density, large aperture, contact ionization sources. The major disadvantage of this approach is the very large size of the injector and matching section. The other option is to use high current density, multiple beamlet ion sources. From various scaling rules, it is found that the multiple beamlet approach is the more attractive one because it can be smaller, and more efficient, although the requirements on the ion source are more demanding.

Extent and contributing factors of drug expenditure of injectors in Glasgow. Multi-site city-wide cross-sectional study.

Recent concern about drug use has focused attention on the illegal income generated by users. To investigate factors associated with drugs expenditure and to estimate the cost of illegal acquisitions used to pay for drugs. We collected self-report data from 954 current injectors, interviewed at multiple street, needle/syringe exchange and drug treatment sites throughout Glasgow. Injectors' mean weekly drug spending was 324 Pounds. The mean annual illegal drugs spend was estimated to be 11,000 Pounds per injector. We provide a central estimate--194 million Pounds per annum--of the retail value of goods acquired illegally by injectors in Glasgow in order to pay for drugs. Higher drug spends were associated with having been imprisoned more often and with those reporting acquisitive crime, drug dealing and prostitution. Treatment with methadone, among individuals who injected in the previous two months, was associated with a 20% reduction in a typical spend on drugs. Treatment effectiveness needs to be measured both in terms of health benefit and in terms of reduction in drugs expenditure and recidivism.

Perceived compliance with AZT dosing among a sample of African-American drug users

The purpose of this report was to present findings from a pilot study conducted to explore the associations between sociodemographic, drug use, and health belief factors and perceived compliance with zidovudine (AZT) among African-American drug users. Data were collected in Washington, DC, USA from individuals who were African-American; were recent or current drug injectors or crack smokers; were HIV-seropositive, and were receiving treatment for HIV infection. Participants were recruited through local organizations that provide services to HIV-infected persons. Participants were interviewed using a questionnaire that solicited sociodemographic, lifetime and current drug use, current sexual behaviours, health status, HIV and drug treatment history, and health belief data. Analyses were limited to individuals currently using an illicit substance and who had received AZT during their medical treatment. Parametric (Pearson's r) and nonparametric (Spearman's rho) statistics were used to assess correlations between perceived compliance with AZT dosing and independent variables. As the study was intended to be both descriptive and exploratory, the level of statistical significance was set at 0.10, rather than the customary 0.05. Antiretroviral medications recognized and recalled by participants are presented. The most commonly recalled medication was AZT. Slightly less than one-third of participants reported being completely compliant with an AZT regimen. Perceived compliance was found to be negatively associated with 5 variables: age, homelessness, number of injections in the previous 30 days, trading sex for drugs, and the perception that AIDS is no longer a serious disease since the development of new antiretroviral medications. Intensity of feelings of joy, fear, and the belief that taking more anti-HIV medications would result in better health were found to be positively correlated. Bivariate associations between perceived compliance and sociodemographic, drug use, sexual behaviour, and health belief variables suggest further avenues of study and potential points for intervention to increase compliance with antiretroviral medications among racial/ethnic minority drug users receiving treatment for HIV infection.

Preventing and curtailing injecting drug use: a review of opportunities for developing and delivering ‘route transition interventions’

AbstractInjecting is an important cause of viral and bacterial infection among drug users and is also associated with increased risk of overdose and severe dependence. Even when aggregate numbers of illicit drug users remain constant, significant health and social benefits may be achieved by a reduction in the prevalence and/or frequency of injecting. Yet, to date, little attention has been paid to reducing injecting (rather than drug use) as a policy objective. This paper reviews a range of ‘route transition interventions' (RTIs) that can be used to reduce injecting and its associated harms. Two points for intervention are distinguished: preventing injecting among existing non‐injecting drug users and promoting the transition away from injecting among current injectors. Targets for basic research and programme evaluation are discussed. In particular, it is argued that the time is now right for regional or national case studies that investigate how injecting can be reduced. [Hunt N, Griffiths P, Southwell M, Stillwell G, Strang J. Preventing and curtailing injecting drug use: a review of opportunities for developing and delivering route transition interventions’. Drug Alcohol Rev 1999;18:441–451]

Methadone maintenance treatment modalities in relation to incidence of HIV: results of the Amsterdam cohort study.

To evaluate methadone maintenance treatment modalities, prescribed within the concept of harm reduction, in relation to incidence of HIV infection among drug users with a history of methadone treatment in Amsterdam, The Netherlands. Prospective observational cohort study among 582 HIV-negative drug users. To ensure valid and detailed assessment of methadone treatment, data from the Central Methadone Register in Amsterdam were linked to the Amsterdam cohort study among drug users. Poisson regression analysis was used to identify independent and significant predictors of incidence of HIV. During 1906 person years, 58 drug users seroconverted, the overall incidence of HIV being 3.0 per 100 person years with a declining trend for current injectors. An increase in frequency of methadone programme attendance [relative risk (RR), 2.4; 95% confidence interval (CI), 1.2-4.6, compared with no change] and increase in methadone dosage (RR, 0.8; 95% CI, 0.6-1.0, per category of change of 10 mg/day) were significantly associated with incidence of HIV in multivariate analysis. Methadone dosage and frequency of programme attendance in itself were not significant predictors. Other multivariate significant risk factors were homelessness, current injecting and in-patient hospital care. Among drug users who receive methadone maintenance treatment in a harm-reduction setting, which includes ancillary services such as needle-exchange programmes and HIV testing and counselling, prescription of high methadone dosages is not sufficient to stop the spread of HIV. However, an individual increase of the methadone dosage and measures to achieve high treatment retention could contribute to the prevention of HIV among drug users.

Lack of legal income is strongly associated with an increased risk of AIDS and death in HIV-infected injecting drug users

The aim of the study was to analyze the impact of soci-economic status in addition to other risk factors in the progression of HIV disease in a cohort of injecting drug users (IDUs) with a mean follow-up of two years. Between 1989 and 1992, 124 HIV-infected IDUs were recruited in a primary care outpatient clinic providing free consultations and free access to therapy. The main outcome measures were death and AIDs-defining events. The proportion of current daily injectors at entry in the study and at the end of follow-up was 67.7% and 57.2%, respectively. The proportion of individuals on maintenance opioid therapy at entry in the study and at the end of follow-up was 0 and 12.1%, respectively. CD4 cell counts below 200 106/L at baseline, positive p24 antigenemia at baseline, the lack of legal income and occasional drug use at entry were risk factors for clinical progression and death. When adjusted in a multivariate analysis, the absence of legal income remained associated with death and occurrence of an AIDS-defining event with a relative risk of 5.2 (1.5-18.1) (p = 0.004). Lack of legal income is a strong risk factor for progression of HIV disease in IDUs, that is independent of CD4 cell count and p24 antigenemia.