Prevalence and severity of abscesses and cellulitis, and their associations with other health outcomes, in a community-based study of people who inject drugs in London, UK

BACKGROUND

Skin and soft tissue infections (SSTI) are a common but preventable cause of morbidity and mortality among people who inject drugs (PWID). They can be severe, and hospitalisations of PWID with SSTI are rising. The most common SSTI presentations are abscesses and cellulitis.

METHODS

We used data from Care & Prevent, a cross-sectional community survey of PWID in London. We reported the lifetime prevalence of SSTI, severity of infections, key risk factors, and associated sequelae. Pictorial questions were used to assess SSTI severity.

RESULTS

We recruited 455 PWID. SSTI lifetime prevalence was high: 64% reported an abscess and/or cellulitis. Over one-third (37%) reported a severe infection, 137 (47%) reported hospitalisation. SSTIrisk factors were: aged 35+ years, injecting once or more times a day, subcutaneous or intra-muscular injections, and making four or more attempts to achieve an injection. Those who reported having other health conditions were at higher odds of having an abscess or cellulitis, with risk tending to increase with number of reported conditions. Half (46%) employed self-care for their worst SSTI, and 43% waited for ten or more days before seeking medical care or not seeking medical care at all.

CONCLUSIONS

Abscess and cellulitis are very common among PWID in London. We corroborate findings indicating SSTIs are associated with risks, e.g. venous access problems, as well as other co-morbid conditions: septicaemia, endocarditis, DVT, and kidney disease. These co-morbidities may impact SSTIs severity and outcomes. Delayed healthcare seeking potentially exacerbates infection severity, which in turn increases poorer health outcomes and complications.

LIVER FIBROSIS IN COMBINED COURSE OF CHRONIC HEPATITIS C AND HIV INFECTION

The urgency of the problem connected with HIV infection and parenteral forms of viral hepatitis largely stems from common epidemiological, social and economic indices. HIV infection accelerates progression of liver disease associated with HCV infection, especially in patients with more severe immunodeficiency. The aim of the study was to compare results of liver elastometry in patients co-infected with HIV/CHC and those monoinfected with CHC. Verification of the diagnosis was carried out on the basis of clinical-anamnestic data, by taking into account the epidemiological history of patients and confirming the results of enzyme immunoassay with the definition of markers of hepatitis C in paired sera and polymerase chain reaction with the detection of RNA virus in blood plasma. The degree of liver fibrosis was measured on a scale of METAVIR by means of FibroScan apparatus. The article presents the results of the comparative assessment of liver fibrosis in patients co-infected with HIV/CHC and those monoinfected with CHC. It suggests that patients co-infected with HIV/CHC are at a higher risk of severe fibrosis and cirrhosis.

COMPARATIVE ANALYSIS OF COMBINED COURSE OF CHRONIC HEPATITIS C AND HIV DEPENDING ON THE ROUTE OF INFECTION

At present, an infection caused by the hepatitis C virus is common among HIV-infected patients. The rapid growth of drug addiction, sexual route of infection transmission, HIV and HCV infection among young people, low efficiency of treatment and lack of specific means of prevention clearly means that this pathology is to be listed among the first in the modern infectology. The aim of the study was to investigate the characteristics of the course of chronic hepatitis C in HIV-infected patients, depending on the route of infection. Study design was open, non-randomized and prospective. A total of 58 HIV-infected patients with chronic hepatitis C registered in the dispensary at Karaganda Regional Center for Prevention and Control of AIDS were examined. The diagnosis of HIV infection was verified by immune blotting. Etiological hepatitis verification was performed by means of enzyme immunoassay and polymerase chain reaction. We present the clinical and laboratory results of HIV-infected patients with chronic hepatitis C, depending on the route of infection. Patients with the sexually transmitted infection experienced asymptomatic course of the disease. In comparison, injecting drug users showed greater clinical symptomatology and a moderate level of activity of the infectious process. These clinical and laboratory findings suggest that the characteristics of the course of chronic hepatitis C in HIV-infected patients depends on the route of infection.

Surgical treatment of infective endocarditis in active intravenous drug users: a justified procedure?

BACKGROUND

Infective endocarditis is a life threatening complication of intravenous drug abuse, which continues to be a major burden with inadequately characterised long-term outcomes. We reviewed our institutional experience of surgical treatment of infective endocarditis in active intravenous drug abusers with the aim of identifying the determinants long-term outcome of this distinct subgroup of infective endocarditis patients.

METHODS

A total of 451 patients underwent surgery for infective endocarditis between January 1993 and July 2013 at the University Hospital of Heidelberg. Of these patients, 20 (7 female, mean age 35 ± 7.7 years) underwent surgery for infective endocarditis with a history of active intravenous drug abuse. Mean follow-up was 2504 ± 1842 days.

RESULTS

Staphylococcus aureus was the most common pathogen detected in preoperative blood cultures. Two patients (10%) died before postoperative day 30. Survival at 1, 5 and 10 years was 90%, 85% and 85%, respectively. Freedom from reoperation was 100%. Higher NYHA functional class, higher EuroSCORE II, HIV infection, longer operating time, postoperative fever and higher requirement for red blood cell transfusion were associated with 90-day mortality.

CONCLUSIONS

In active intravenous drug abusers, surgical treatment for infective endocarditis should be performed as extensively as possible and be followed by an aggressive postoperative antibiotic therapy to avoid high mortality. Early surgical intervention is advisable in patients with precipitous cardiac deterioration and under conditions of staphylococcal endocarditis. However, larger studies are necessary to confirm our preliminary results.

HCV RNA levels in a multiethnic cohort of injection drug users: human genetic, viral and demographic associations

In patients with chronic hepatitis C, the hepatitis C virus (HCV) RNA level is an important predictor of treatment response. To explore the relationship of HCV RNA with viral and demographic factors, as well as IL28B genotype, we examined viral levels in an ethnically diverse group of injection drug users (IDUs). Between 1998 and 2000, the Urban Health Study (UHS) recruited IDUs from street settings in San Francisco Bay area neighborhoods. Participants who were positive by HCV enzyme immunoassay were tested for HCV viremia by a branched-chain DNA assay. HCV genotype was determined by sequencing the HCV nonstructural 5B protein region. For a subset of participants, IL28B rs12979860 genotype was determined by Taqman. Among 1,701 participants with HCV viremia, median age was 46 years and median duration of injection drug use was 26 years; 56.0% were African American and 34.0% were of European ancestry (non-Hispanic). Human immunodeficiency virus type 1 (HIV-1) prevalence was 13.9%. The overall median HCV RNA level was 6.45 log(10) copies/mL. In unadjusted analyses, higher levels were found with older age, male gender, African-American ancestry, hepatitis B virus infection, HIV-1 infection, and IL28B rs12979860-CC genotype; compared to participants infected with HCV genotype 1, HCV RNA was lower in participants with genotypes 3 or 4. In an adjusted analysis, age, gender, racial ancestry, HIV-1 infection, HCV genotype, and IL28B rs12979860 genotype were all independently associated with HCV RNA.

CONCLUSION

The level of HCV viremia is influenced by a large number of demographic, viral, and human genetic factors.

Prospective study of bone mineral density changes in aging men with or at risk for HIV infection

OBJECTIVE

To investigate rates and predictors of change in bone mineral density (BMD) in a cohort of aging men with or at risk for HIV infection.

DESIGN

A prospective cohort study among 230 HIV-infected and 159 HIV-uninfected men aged at least 49 years.

METHODS

Longitudinal analyses of annual change in BMD at the femoral neck, total hip, and lumbar spine.

RESULTS

At baseline, 46% of men had normal BMD, 42% had osteopenia, and 12% had osteoporosis. Of those men with normal BMD, 14% progressed to osteopenia and 86% continued to have normal BMD. Of the men initially with osteopenia, 12% progressed to osteoporosis and 83% continued to have osteopenia. Osteopenia incidence per 100 person-years at risk was 2.6 for HIV-uninfected men and 7.2 for HIV-infected men; osteoporosis incidence was 2.2 per 100 person-years at risk among men with osteopenia, regardless of HIV status. In multivariable analysis of annual change in BMD at the femoral neck, we found a significant interaction between heroin use and AIDS diagnosis, such that the greatest bone loss occurred with both AIDS and heroin use (adjusted predicted mean annual bone loss 0.0196 g/cm). Hepatitis C virus seropositivity was also associated with femoral neck bone loss (P = 0.04). The interaction between AIDS and heroin use also was associated with bone loss at the total hip, as was current methadone use (P < 0.01).

CONCLUSION

We found an association of heroin use and AIDS with BMD change, suggesting that heroin users with AIDS may be at particular risk for bone loss.

The standing heel-rise test: relation to chronic venous disorders and balance, gait, and walk time in injection drug users

Injection drug use can impair mobility. When mobility is impaired in combination with other potential pathologic changes to the veins, muscles, and joints of the lower legs, chronic venous disorders can develop. The heel-rise test, an assessment of eccentric-concentric muscle action of calf muscle function with regard to plantar flexion, can be used to measure ankle mobility. To examine the test-retest reliability and construct validity of the heel-rise test in relation to chronic venous disorders in persons with a history of injection drug use (N = 104), a test-retest study (M = 45.9+/-12.9 days from first to second test) was conducted. Participants were assessed for chronic venous disorders of the legs and walk time; they also completed the heel-rise and Tinetti Balance and Gait tests. Test-retest reliability was found to be good for full heel rise of right and left legs (ICC = .66 and .67, respectively). Heel-rise performance was positively correlated with balance (r = .38 to .47) and gait (r = .38 to .45) and negatively related to walk time (r = -.30 to -.35) (P <0.01). Participants who injected in the groin, legs, or feet performed fewer heel rises than those who injected in the arms and upper body only or those who did not inject drugs. Chronic venous disorders accounted for 7% to 17% of the variance in heel rise. The heel-rise test as a measure of calf muscle function is supported by these results, implicating the role of mobility restriction in the etiology of venous disease. Although more research is needed regarding its performance, the heel-rise test may be a low-cost, noninvasive screening or assessment tool in a variety of outpatient settings.

Comorbidities among HIV-infected injection drug users in Chennai, India

BACKGROUND & OBJECTIVE

HIV-infected injection drugs users (IDUs) are known to have high rates of co-infections. A few reports exist on comorbidities among HIV-infected IDUs in India. We carried out a retrospective study to analyse data on comorbidities in India and treatment challenges faced when treating HIV-infected IDUs in India.

METHODS

A retrospective chart review of 118 HIV-infected IDUs who accessed care at the YRG Centre for Substance Abuse-Related Research, Chennai, between August 2005 and February 2006 was done. Demographic, laboratory and clinical information was extracted from medical records. Descriptive demographic and clinical characteristics and distributions of comorbidities across CD4 cell count strata were analysed.

RESULTS

All IDUs were male with a median age of 35.5 yr. The majority were married with average monthly income less than INR 3000 per month. The prevalence of hepatitis B and C infections were 11.9 and 94.1 per cent, respectively. Other common co-morbidities included oral candidiasis (43.2%), tuberculosis (33.9%), anaemia (22.9%), lower respiratory tract infections (16.1%), cellulitis (6.8%), herpes zoster (9.3%) and herpes simplex (9.3%). Among participants with CD4+ < 200 cells/microl, the prevalence of TB was 60 per cent.

INTERPRETATION & CONCLUSION

IDUs in Chennai were commonly co-infected with HBV, HCV and tuberculosis, complicating use of antiretroviral and anti-tuberculous therapy. The current regimens available for the management of HIV and TB in India may need to be re-assessed for IDUs given the potential for increased rates of hepatotoxicity.

Increased breakpoints on a progressive ratio schedule reinforced by IV cocaine are associated with reduced locomotor activation and reduced dopamine efflux in nucleus accumbens shell in rats

RATIONALE

It has been hypothesized that sensitization of the neurochemical effects within the mesolimbic dopamine (DA) system might account for specific aspects of the addiction process. We have recently developed a self-administration procedure which produces increases in responding reinforced by cocaine on a progressive ratio (PR) schedule. This may reflect an increased motivation to self-administer cocaine, one hallmark of addiction.

OBJECTIVES

The goal of this experiment was to investigate behavioral and neurochemical changes associated with increased cocaine self-administration on a PR schedule.

MATERIALS AND METHODS

Rats self-administered cocaine over 14 days under a PR schedule. Cocaine-stimulated locomotor activity was evaluated before as well as 1 or 14 days after self-administration training. Cocaine-induced DA changes in the core and shell of the nucleus accumbens in the same animals were also examined.

RESULTS

Subjects showed increased responding over time, to about 200% of baseline. Cocaine-induced locomotor activation was decreased at both withdrawal times compared to naïve animals. Microdialysis showed no differences after self-administration in the nucleus accumbens core dopamine response at either time point. There was, however, a significant decrease in the dopamine response to cocaine in the shell of the nucleus accumbens.

CONCLUSION

The present results demonstrate that a progressive increase in breakpoints on a PR schedule can be established in rats at a time when the ability of cocaine to increase extracellular DA levels and stimulate locomotor activity is reduced. Therefore, sensitization of the mesolimbic DA system does not account for the observed change in drug-taking behavior.

The anatomy of risk: a quantitative investigation into injection drug users' taxonomy of risk attitudes and perceptions

The authors report on the first study to use the systematic quantitative methods of the psychometric paradigm of risk analysis to examine risk perceptions among substance abusers. Fifty opioid-dependent injection drug users (IDUs) and 50 matched, control individuals completed a series of measures to provide quantitative representations of risk perceptions about 53 risk-laden items (including activities, substances, technologies, and diseases). Results indicated that risk perceptions of IDUs and controls were highly correlated on many items; however, IDUs perceived several items, such as hepatitis, HIV, handguns, and unprotected sex, as markedly more risky. IDUs also perceived both themselves and others as having greater risk of contracting hepatitis and HIV. IDUs wanted significantly reduced regulation of drugs, including prescription drugs, heroin, valium, and barbiturates. Factor analyses conducted to understand how risk ratings related to various characteristics that have been shown to influence risk perception revealed 3 factors that account for approximately 80% of the variability in risk perception across groups: Factor 1, related to the severity of the risk; Factor 2, related to the certainty of the risk; and Factor 3, related to the immediacy of the risk. However, IDUs more strongly associated the extent to which they were personally affected by a risk item and the extent to which the risk affected fewer or more people to Factor 1, whereas control participants more strongly associated these characteristics with Factor 2. Identifying improved methodologies for evaluating the risk perceptions of IDUs may be of considerable utility in understanding their high-risk behavior.

High reinforcing efficacy of nicotine in non-human primates

Although tobacco appears highly addictive in humans, there has been persistent controversy about the ability of its psychoactive ingredient nicotine to induce self-administration behavior in laboratory animals, bringing into question nicotine's role in reinforcing tobacco smoking. Because of ethical difficulties in inducing nicotine dependence in naïve human subjects, we explored reinforcing effects of nicotine in experimentally-naive non-human primates given access to nicotine for periods of time up to two years. Five squirrel monkeys with no experimental history were allowed to intravenously self-administer nicotine by pressing one of two levers. The number of presses on the active lever needed to obtain each injection was fixed (fixed-ratio schedule) or increased progressively with successive injections during the session (progressive-ratio schedule), allowing evaluation of both reinforcing and motivational effects of nicotine under conditions of increasing response cost. Over time, a progressive shift toward high rates of responding on the active lever, but not the inactive lever, developed. The monkeys' behavior was clearly directed toward nicotine self-administration, rather than presentation of environmental stimuli associated with nicotine injection. Both schedules of reinforcement revealed a high motivation to self-administer nicotine, with monkeys continuing to press the lever when up to 600 lever-presses were needed for each injection of nicotine. Thus, nicotine, by itself, in the absence of behavioral or drug-exposure history, is a robust and highly effective reinforcer of drug-taking behavior in a non-human primate model predictive of human behavior. This supports the use of nicotinic ligands for the treatment of smokers, and this novel preclinical model offers opportunities to test future medications for the treatment of nicotine dependence.

Physical activity in a cohort of HIV-positive and HIV-negative injection drug users

Physical activity is beneficial for persons with HIV infection but little is known about the relationships between physical activity, HIV treatment and injection drug use (IDU). This study compared physical activity levels between HIV-negative and HIV-positive injection drug users (IDUs) and between HIV-positive participants not on any treatment and participants on highly active antiretroviral therapy (HAART). Anthropometric measurements were obtained and an interviewer-administered modified Paffenbarger physical activity questionnaire was administered to 324 participants in a sub-study of the AIDS Linked to Intravenous Experiences (ALIVE) cohort, an ongoing study of HIV-negative and HIV-positive IDUs. Generalized linear models were used to obtain univariate means and to adjust for confounding (age, gender, employment and recent IDU). Vigorous activity was lower among HAART participants than HIV-positive participants not on treatment (p=0.0025) and somewhat lower than HIV-negative participants (p=0.11). Injection drug use and viral load were not associated with vigorous activity. Energy expenditure in vigorous activity was also lower among HAART participants than both HIV-negative and HIV-positive participants not on treatment. Thus, HIV-positive participants on HAART spend less time on vigorous activity independent of recent IDU. More research is needed into the reasons and mechanism for the lack of vigorous activities, including behavioral, psychological and physiological reasons.

Dietary intake and body mass index in HIV-positive and HIV-negative drug abusers of Hispanic ethnicity

Objective:

Malnutrition in drug abusers has been attributed to poor diet. However, previous studies are conflicting. Many studies have not considered possible concurrent HIV disease. The purpose of this study was to determine the relationship between drug abuse and dietary intake in Hispanic Americans with and without HIV infection.

Design:

Dietary intake was measured using 3-day food records and 24-hour dietary recalls in three groups: HIV-positive drug abusers, HIV-negative drug abusers and HIV-positive persons who do not use drugs (‘non-drug abusers’).

Setting:

The baseline data from a prospective cohort study of the role of drug abuse in HIV/AIDS weight loss and malnutrition conducted in Boston, Massachusetts, USA.

Subjects:

The first 284 participants to enrol in the study.

Results:

HIV-positive drug abusers had a body mass index (BMI) that was significantly lower than that of HIV-positive non-drug abusers. Reported energy, fat and fibre intakes did not differ between groups. All groups had median reported intakes of vitamin A, vitamin B6, vitamin B12, selenium and zinc that were in excess of the dietary reference values (DRI). Intakes of α-tocopherol were below the DRI, but did not differ from intakes of the general US population. However, increasing levels of drug abuse were associated with lower reported intakes of vitamin B6, vitamin B12, selenium and zinc.

Conclusions:

Overall, this study does not support the notion that dietary intake can explain the lower BMI of HIV-positive drug abusers. Further studies examining non-dietary determinants of nutritional status in drug abusers are warranted.

Escalation of i.v. cocaine self-administration and reinstatement of cocaine-seeking behavior in rats bred for high and low saccharin intake

RATIONALE

Rats selectively bred for high saccharin (HiS) intake consume more alcohol, acquire intravenous (i.v.) cocaine self-administration more rapidly, and show more dysregulated patterns of cocaine self-administration than their low saccharin-consuming (LoS) counterparts.

OBJECTIVES

The purpose of the present study was to determine whether HiS and LoS rats also differ in the escalation, maintenance, extinction, and reinstatement of i.v. cocaine self-administration.

MATERIALS AND METHODS

Two experiments were conducted in separate groups of rats. In the first experiment, HiS and LoS female rats were allowed to self-administer cocaine [0.4 mg/kg; fixed ratio (FR) 1] under short (ShA, 2 h per day) or long (LgA, 12 h per day) access conditions for 21 days. Session lengths were subsequently equated (2 h), and FR1-maintained cocaine self-administration was examined. In the second experiment, additional groups of HiS and LoS female rats were given access to cocaine (0.4 mg/kg; FR 1) self-administration during 2-h sessions for 10 days. Subsequently, saline was substituted for cocaine, and responding was extinguished. After a 14-day extinction period, saline- and cocaine-[5, 10, and 15 mg/kg, intraperitoneal (i.p.)] induced reinstatement of drug-seeking behavior was measured.

RESULTS

HiS LgA rats escalated their cocaine intake more rapidly than LoS rats, and during the 2 h sessions after escalation cocaine self-administration was significantly higher in HiS LgA rats, compared to LoS LgA rats. HiS rats responded on the cocaine-paired lever more than LoS rats during maintenance, extinction, and cocaine-(15 mg/kg) induced reinstatement.

CONCLUSIONS

These results suggest that HiS and LoS rats have distinct drug-seeking and drug-taking profiles. The HiS and LoS rats differ along a wide range of behavioral dimensions and represent an important model to study the interactions of excessive intake of dietary substances and vulnerability to drug abuse.

Effect of rate of administration on subjective and physiological effects of intravenous cocaine in humans

The rate hypothesis of psychoactive drug action holds that the faster a drug reaches the brain and starts to act, the greater its reinforcing effects and abuse liability. A previous human study using a single cocaine dose confirmed the rate hypothesis for subjective responses, but found no rate effect on cardiovascular responses. We evaluated the rate hypothesis in 17 experienced cocaine users (7 [all men] provided complete data; 6 participated in only 1-2 sessions) by administering IV cocaine at each of three doses (10, 25, 50 mg) and injection durations (10, 30, 60 s) in a double-blind, placebo-controlled, escalating dose design. Heart rate, blood pressure, and positive (e.g., rush, high) and negative (e.g., feel bad, anxious) subjective effects (100-mm visual analogue scales) were measured for 1h after dosing. Peak change from baseline, time to peak, and area under the time-response curve were evaluated with repeated measures mixed linear regression analyses, allowing use of data from all sessions for all subjects, including non-completers. Both dose (mg) and infusion rate (mg/s) significantly influenced most subjective and cardiovascular variables. Analysis of the interaction suggested that dose had a stronger impact than rate. Rate had a stronger influence on positive subjective effects than on negative subjective effects or cardiovascular variables. These findings provide support for the rate hypothesis as it applies to both subjective and cardiovascular effects of IV cocaine administration in humans.

How to achieve chronic intravenous drug self-administration in mice

INTRODUCTION

Self-administration, the best animal model of drug addiction, requires implantation of indwelling jugular catheters. Surgical procedures in mice, the most common species for transgenic modeling, are difficult owing to size and scale. The goal of this paper was to describe how to achieve successful intravenous drug self-administration in mice.

METHOD

The surgical and self-administration training procedures developed for rats and other species have been adopted for mice and described in a step-by-step manner with reference to sources for equipment, materials, and parts.

RESULTS

The method can be used for studying self-administration behavior in freely moving mice up to 4 weeks. The relatively quick loss of catheter patency was due to growth of neointima tissue.

DISCUSSION

Drug self-administration is achievable in mice, and the model is limited only by eventual loss of catheter patency, a process probably triggered by mechanical damage of the endothelium, by the effect of drug injections, or a combination of these factors.

Investigating Neurocognitive Features of Hepatitis C Virus Infection in Drug Users: Potential Challenges and Lessons Learned from the HIV Literature

Studies of neurocognition in drug users with hepatitis C virus (HCV) infection are urgently needed but face many challenges. We review similarities between human immunodeficiency virus (HIV) and HCV infection in their neurocognitive features, discuss challenges associated with research among drug users, advocate that the HIV literature can usefully inform studies of HCV, and review findings by our group on neurocognition among substance users with HIV and/or HCV infection.

The effect of HIV infection on overdose mortality

OBJECTIVES

To quantify the association of HIV infection with overdose mortality and explore the potential mechanisms.

DESIGN

A prospective cohort study.

METHODS

A total of 1927 actively injecting drug users who were HIV seronegative at baseline, of whom 308 later HIV seroconverted, were followed semi-annually for death from 1988 to 2001. Survival analyses using marginal structural and standard Cox models were used to evaluate the effect of HIV infection on the risk of overdose mortality.

RESULTS

Overdose death rates were higher in HIV-seropositive than HIV-seronegative drug users: 13.9 and 5.6 per 1000 person-years, respectively (P < 0.01). The hazard ratio (HR) was 2.54 [95% confidence interval (CI) 1.47, 4.38] for the marginal structural model and 2.06 (95% CI 1.25, 3.38) for the standard Cox model, both adjusted for demographics, drug injection characteristics, alcohol abuse, substance abuse treatment, and sexual orientation. Adjusting for possible time-varying mediators (i.e. drug use, medical conditions and healthcare access) in extended marginal structural models reduced the effect of HIV on overdose mortality by 30% (HR 1.82, 95% CI 1.01, 3.30). Abnormal liver function was associated with a higher risk of overdose mortality (HR 2.00, 95% CI 1.05, 3.84); adjustment for this further reduced the effect of HIV on overdose mortality.

CONCLUSION

HIV infection was associated with a higher risk of overdose mortality. Drug use behavior, systematic disease and liver damage associated with HIV infection appeared to account for a substantial portion of this association. The data suggest a group to target with interventions to reduce overdose mortality rates.

Cocaine and heroin ('speedball') self-administration: the involvement of nucleus accumbens dopamine and mu-opiate, but not delta-opiate receptors

RATIONALE

The combined administration of heroin and cocaine ('speedball') is common among intravenous drug users. Dopamine receptors in the nucleus accumbens play a key role in cocaine self-administration; however, their role in speedball self-administration is unknown, as is the role of opiate receptors in this region.

OBJECTIVES

The effect of blocking dopamine D1, D2, mu-opiate or delta-opiate receptors in the nucleus accumbens on the intravenous self-administration of combined heroin and cocaine was examined in rats.

METHODS

Rats with bilateral cannulae implanted into the nucleus accumbens were trained to self-administer intravenous speedball (ratio of cocaine/heroin, 17:1) under a progressive ratio (PR) schedule. Prior to their self-administration session, rats were then microinjected with the dopamine D1 receptor antagonist SCH 23390 (1 and 6 nmol side(-1)), the D2 receptor antagonist raclopride (3 and 10 nmol side(-1)), the mu-opiate receptor antagonist CTOP (0.1, 0.3 and 1.0 nmol side(-1)), the delta-opiate receptor antagonist naltrindole (1.0, 3.0 and 10 nmol side(-1)) or a cocktail of SCH 23390 (1 nmol side(-1)) and CTOP (0.1 nmol side(-1)) into the nucleus accumbens.

RESULTS

Microinjection of SCH 23390, raclopride or CTOP into the nucleus accumbens produced dose-dependent decreases in breakpoints under the PR schedule, while naltrindole was without effect. The highest dose of SCH 23390 also significantly reduced locomotor activity measured during speedball self-administration. The combination of SCH 23390 and CTOP significantly reduced breakpoints, while not affecting locomotor activity.

CONCLUSIONS

These results indicate that dopamine and mu-opiate receptors, but not delta-opiate receptors, in the nucleus accumbens are involved in the reinforcing effects of speedball. Combined administration of D1 and mu-opiate receptor antagonists may be more selective at reducing the reinforcing effects of speedball self-administration than either drug alone.

Serial position effects in HIV-infected injecting drug users

This study examined memory and serial position effects in HIV-positive injecting drug users (IDUs), HIV-negative IDUs, and nondrug using control participants. Exploratory analyses investigating a possible mediating role of executive functions with HIV infection, drug use, and memory were also performed. Control participants showed stronger primacy effects than did both HIV-positive and HIV-negative IDUs and also outperformed the drug using groups on all memory measures. Interestingly, analysis of the role of executive functions with HIV infection, drug use, and memory suggested that executive functioning may mediate the verbal memory deficits associated with HIV infection, but not those associated with IDU.

Does drug abuse beget drug abuse? Behavioral analysis of addiction liability in animal models of prenatal drug exposure

Prenatal exposure to drugs of abuse is the single largest preventable cause of developmental compromise of American children today. In the clinical population, it is difficult to determine the independent effects of gestational exposure to a single drug on brain development, in part due to the confounding effects of additional risk factors that are encountered in the substance-abusing population. The enormous clinical and societal problem of gestational toxicity of drugs of abuse, both legal and illegal, has driven the need to develop and investigate animal models of gestational drug exposure in which these variables can be controlled. More specifically, as clinical data are gathered suggesting an increased liability to substance abuse among children of drug-abusing mothers, a mechanistic understanding of the lasting effects of early drug exposure on the developing brain and the behavioral repertoire of the developing animal is crucial. In this review we summarize experimental animal research that investigates the role of drug exposure in utero on the functional development of specific brain circuits that are involved in the reinforcing effects of drugs of abuse, and on the behaviors that are mediated by these brain reward systems.

Malaria in injection drug abusers in Vietnam

A prospective case-control study was conducted in a referral hospital in Ho Chi Minh City, Vietnam, to compare the clinical and laboratory features and outcome of severe falciparum malaria in injection drug abusers (IDAs) with those of patients who had acquired malaria by mosquito bite. From 1991 to 1996, 70 IDAs were admitted to the hospital, of whom at least 32 had acquired malaria by needle sharing. Although IDAs were more likely than control patients with severe malaria to be malnourished and to have coincident hepatitis B, hepatitis C, and human immunodeficiency virus infections, the overall rates of mortality, complications, and recovery were similar in the 2 groups. The route of malaria acquisition did not affect the outcome of severe malaria. The management of severe malaria in IDAs is similar to that for other patients.

Intravenous buprenorphine self-administration by detoxified heroin abusers

Several sources indicate that intravenously administered buprenorphine may have significant abuse liability in humans. The present study evaluated the reinforcing effects of intravenously administered buprenorphine (0, 2, and 8 mg) in detoxified heroin-dependent participants during a 7.5-week inpatient study. Participants (n = 6) were detoxified from heroin over a 1.5-week period immediately after admission. Testing subsequently occurred in three 2-week blocks. During the first week of each 2-week block, the reinforcing effects of buprenorphine were evaluated. Participants first received a dose of buprenorphine and $20 and then were given either the opportunity to self-administer the dose or $20 during choice sessions. During the second week of each 2-week block, the direct effects of heroin were measured to evaluate potential long-lasting antagonist effects of buprenorphine. Progressive ratio break-point values were significantly higher after 2 and 8 mg of buprenorphine compared with placebo. Correspondingly, several positive subjective ratings increased after administration of active buprenorphine relative to placebo. Although there were few differences in peak effects produced by 2 versus 8 mg of buprenorphine, the higher buprenorphine dose generally produced longer-lasting effects. Heroin also produced dose-related increases in several subjective effects. Peak ratings produced by heroin were generally higher than peak ratings produced by buprenorphine. There was little evidence of residual antagonism produced by buprenorphine. These results demonstrate that buprenorphine served as a reinforcer under these conditions, and that it may have abuse liability in nonopioid-dependent individuals who abuse heroin.

The correlates of dietary intake among HIV-positive adults

BACKGROUND

Dietary adequacy, as distinct from weight loss, has not been examined thoroughly in a diverse cohort of HIV-infected individuals.

OBJECTIVE

An analysis was undertaken to determine the correlates of inadequate dietary intake among HIV-infected adults.

DESIGN

In a cross-sectional study of 463 men and 170 women (aged 21-70 y) with HIV infection, dietary adequacy was evaluated by using 3-d diet records.

RESULTS

Among nondieting males, whites had higher energy intakes than did nonwhites. Injection drug users consumed less energy than did nonusers. Among nondieting females, only the absence of nausea and vomiting was marginally associated with higher energy intakes. Inadequate energy intake, which occurred in 38% of this population, was independently associated with female sex among nondieters. A significant proportion of the study cohort (52%) was consuming less than the recommended dietary allowance of vitamin A. Inadequate protein intake, found in 11% of the study population, occurred more often in females, those without a caregiving adult in the household, and individuals with reduced appetite. A considerable proportion of the participants (23%) reported that they were dieting to lose weight.

CONCLUSIONS

Dietary inadequacy was strongly correlated with being in the sociodemographic groups that are at heightened risk of adverse clinical outcomes. It may be worthwhile to study dietary intake as a potential determinant of the clinical outcomes of HIV infection.

Host genetic background at CCR5 chemokine receptor and vitamin D receptor loci and human immunodeficiency virus (HIV) type 1 disease progression among HIV-seropositive injection drug users

The effect of polymorphisms on genes encoding the CCR5 chemokine receptor and vitamin D receptor (VDR) in human immunodeficiency virus (HIV) type 1 disease progression was analyzed in a cohort of 185 HIV-seropositive injection drug users. Results confirmed a lack of association in patients with HIV disease between CCR5 wtDelta32 heterozygosity and a slow progression to AIDS and to a CD4 cell count <200 cells/microL. In contrast, a more rapid disease progression was associated with the VDR-BB genotype. A higher proportion of this genotype was found in patients with <200 CD4 cells/microL (P=.009; odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3-4.7), as well as a faster progression both to AIDS (1993 CDC classification [CDC 1993]) and to a CD4 cell count <200 cells/microL. When the analysis was restricted to patients with a VDR-bb genetic background, patients with CCR5 wtDelta32 heterozygosity were overrepresented in CDC 1993 nonprogressors (P=.033; OR, 0.28; 95% CI, 0.08-0.92) and in those with >200 CD4 cells/microL (P=.062; OR, 0.26; 95% CI, 0.06-1.08). Also, patients with CCR5 wtDelta32 heterozygosity showed a slow progression both to AIDS CDC 1993 and to a CD4 cell count <200 cells/microL.

Onset and pattern of substance use in intravenous drug users of an opiate maintenance program

OBJECTIVES

To assess the initiation of substance use of participants in an opiate maintenance program by a cross-sectional survey.

METHOD

Participants (n=184) filled out a questionnaire assessing age at initial substance use and age at onset of regular drug use.

RESULTS

Of 15 substances investigated, alcohol, nicotine, analgesics and marijuana were initiated and consumed regularly before the age of 18 years. Barbiturates, benzodiazepines, cocaine, and opiates were begun later. The time gap between initial and regular use varied depending on the substance. Regular use exceeded 50% for alcohol, benzodiazepines, cocaine, heroin, marijuana and nicotine.

CONCLUSIONS

Specific knowledge about the age of onset and sequence of substances used by drug addicts may help to prevent substance use more age specifically.

Heroin smoking by "chasing the dragon" in young opiate users in Ireland: stability and associations with use to "come down" off "Ecstasy"

We explored the frequency of commencing opiate use by "chasing the dragon" to "come down" off Ecstasy and the stability of heroin smoking in young opiate takers by assessing 102 subjects in Dublin using a semistructured interview. Ninety-two subjects had used Ecstasy. Of these, 68 reported "chasing" to "come down" off Ecstasy at some point in their history and were found to have used Ecstasy more frequently and in larger amounts. Thirty-six reported that their first experience of using opiates was to "come down" off Ecstasy, 28 citing this as their main reason for commencement.Eighty-six of the 102 commenced opiates by "chasing" heroin, 61 of whom progressed to injecting after a mean of 2.9 years. This was associated with starting illicit drug use earlier, starting heroin earlier, and a history of using Ecstasy. Implications for service planners in developing responses to illicit drug use among adolescents are discussed.

Adverse drinking consequences among alcohol abusing intravenous drug users

BACKGROUND

Heavy alcohol use is common among out-of-treatment injection drug users (IDUs); however, the relationship between alcohol and drug use behaviors in codependent populations is not well understood. Our specific objectives were (1) to describe the psychometric properties of the Drinker Inventory of Consequences (DrInC) in a sample of active IDUs, and (2) to compare DrInC scores of active IDUs with those reported for the alcohol treatment seeking sample on which the instrument was developed.

METHODS

Interview data were collected from 187 active IDUs who scored positively (> or = 8) on the Alcohol Use Disorders Identification Test, who were recruited from a Providence, RI, needle exchange program (1998-1999). DrInC total and subscale scores for the 159 (85%) participants who met DSM-IV criteria for alcohol abuse/dependence were analyzed. Six-month follow-up data were used to estimate test-retest reliability.

RESULTS

The DrInC total scale exhibited high internal consistency and test-retest reliability. With the exception of adverse physical consequences, reliability estimates for DrInC subscales were good to very good. These data indicate higher subscale redundancy than reported for the development sample. Active IDUs had significantly higher adverse impulse control consequences than the alcohol treatment seeking population on which the instrument was developed.

CONCLUSIONS

The DrInC exhibits desirable psychometric properties for assessing adverse drinking consequences in active IDU populations. IDUs who met DSM-IV criteria for alcohol abuse/dependence reported overall levels of adverse drinking consequences comparable with non-IDU alcohol treatment populations but were more likely to exhibit adverse impulse control consequences.

The Lazarus phenomenon following recreational drug use

A case is reported of the Lazarus phenomenon (the return of spontaneous circulation after cardiopulmonary resuscitation had been abandoned) in a patient following recreational drug use. The implications for management of cardiac arrest in the emergency department are discussed.

Body composition and dietary intake in relation to drug abuse in a cohort of HIV-positive persons

We examined the relationships between drug abuse, weight, body composition, and dietary intake in persons infected with HIV in a cross-sectional analysis of baseline data from a longitudinal study of nutritional status and HIV. Body composition was measured by bioelectrical impedance analysis. Dietary data were collected by 3-day food records or 24-hour recalls. We analyzed data from 39 current intravenous drug users (IVDU), 103 past intravenous drug users (past-IVDU), 239 users of nonintravenous drugs (users-NIVD), and 61 nonusers (reference category). In the men, there were no differences in weight, body mass index (BMI), or body composition among the drug-use groups. In the women, there was a trend to lower weight and BMI across the drug use categories: IVDU women had lower average weight (-13.7 kg; p = .006), BMI (-5.6 units; p = .003) and less fat mass than non-users (-9.8 kg; p = .0001). In women, drug users had higher weight-adjusted energy intakes than nonusers, whereas in the men both drug using groups, NIVD and IVDU, had higher energy intakes than nonusers. These data suggest that intravenous drug-abuse is associated with lower weight and fat mass in women with HIV infection despite adequate self-reported energy intake.

Nutrition, HIV, and drug abuse: the molecular basis of a unique role for selenium

HIV-infected injection drug users (IDUs) often suffer from serious nutritional deficiencies. This is a concern because plasma levels of micronutrients such as vitamin B12, zinc, and selenium have been correlated with mortality risk in HIV-positive populations. Injection drug use also increases lipid peroxidation and other indicators of oxidative stress, which, combined with antioxidant deficiencies, can stimulate HIV-1 replication through activation of NF-kappaB transcription factors, while weakening immune defenses. As detailed herein, these prooxidant stimuli can also increase the pathogenic effects of HIV-1 by another mechanism, involving viral selenoproteins. Overlapping the envelope coding region, HIV-1 encodes a truncated glutathione peroxidase (GPx) gene (see #6 in reference list). Sequence analysis and molecular modeling show that this viral GPx (vGPx) module has highly significant structural similarity to known mammalian GPx, with conservation of the catalytic triad of selenocysteine (Sec), glutamine, and tryptophan. In addition to other functions, HIV-1 vGPx may serve as a negative regulator of proviral transcription, by acting as an NF-kappaB inhibitor (a known property of cellular GPx). Another potential selenoprotein coding function of HIV-1 is associated with the 3' end of the nef gene, which terminates in a conserved UGA (potential Sec) codon in the context of a sequence (Cys-Sec) identical to the C-terminal redox center of thioredoxin reductase, another cellular regulator of NF-kappaB. Thus, in combination with known cellular mechanisms involving Se, viral selenoproteins may represent a unique mechanism by which HIV-1 monitors and exploits an essential micronutrient to optimize its replication relative to the host.

[Axillary plexus catheter block in accidental intra-arterial levomethadone HCl injection in an HIV-positive, hepatitis B and C active drug dependent patient]

We report the case of a 36-year-old male patient who inadvertently injected intraarterially (radial artery) levomethadon-HCl-solution (15 ml corresponding to 37.5 mg) which was intended for substitutional use only. He subsequently developed all clinical signs of malperfusion of his left lower arm and entire hand. Reaching the clinic only two hours after the injection, he received a continuous axillary plexus block which led to the nearly complete restoration of the perfusion of his left lower arm and hand. Thus, we were able to avoid further surgical interventions. We were using the new local anesthetic substance Ropivacain (Naropin), which offers the advantage of 12-hour-injection intervals. Already 36 hours after the "trauma", colour-coded Doppler sonography demonstrated normal flow-rates of the radial, ulnar, and common digital arteries. Only the arterial flow of the index and middle fingers was not detectable at that time--corresponding to partial hypaesthesia of the tip of the second and radial side of the third digits. Even if there are no studies concerning the continuous axillary plexus block in HIV, hepatitis B- and C-positive patients, this anaesthesiological technique should not be withheld from this group of immunocompromised patients.

Effects of an alternative reinforcer on intravenous heroin self-administration by humans

Five heroin-dependent research volunteers, maintained on divided daily oral morphine doses, participated in an inpatient study designed to evaluate intravenous (i.v.) heroin self-administration when money ($10, $20 or $40) was concurrently available. Each morning participants received a single injection of heroin (placebo, 6.25, 12.5, 25, or 50 mg/70 kg, i.v.) and each afternoon, they had the opportunity to self-administer all or part of the morning dose. Participants responded under a progressive-ratio schedule (50, 100, ..., 2800) during a 10-trial self-administration task. During each trial, participants could respond for 1/10th of the sampled heroin dose or 1/10th of a single money value. The progressive-ratio value increased independently for each option. The total amount of heroin and/or money chosen during the self-administration task was administered at the end of the task. Heroin dose-dependently increased ratings of 'good drug effect' and 'high', impaired task performance and decreased pupil diameter and blood oxygen saturation. Heroin also dose-dependently increased progressive-ratio break point values, which varied as a function of the alternative money amount. Consistent with previous studies, the present results demonstrate that alternative reinforcers, depending on magnitude, are effective in reducing heroin use in opioid-dependent individuals.

Effects of acute intravenous cocaine on cardiovascular function, human learning, and performance in cocaine addicts

Continuous non-invasive cardiovascular monitoring in eight healthy cocaine addicts receiving intravenous cocaine (0.325 mg/kg or 0.650 mg/kg) or placebo in double-blind, randomized, cross-over fashion demonstrated significant dose-dependent increases in pulse and mean arterial pressure following cocaine. Pulse and mean arterial pressure peaked 5 min post-cocaine injection and maximal response was sustained for a further 15 min and 35 min afterwards, respectively. Cocaine administration had no significant effect on peripheral oxygen saturation, and no clinically significant abnormalities of rhythm or conduction were seen on the electrocardiogram. These doses and method of single-dose intravenous cocaine administration, and our procedures for cardiovascular monitoring, appear relatively safe for laboratory studies of healthy cocaine addicts with no pre-existing cardiovascular disease. In addition, cocaine-taking (0.325 mg/kg i.v. and 0.650 mg/kg i.v.) was associated with enhanced attention (i.e. increased numbers of correct responses on the Rapid Visual Information Processing Task), but the trend towards reduced reaction time did not achieve statistical significance. Cocaine-taking resulted in a small but statistically insignificant improvement in learning on the Digit Symbol Substitution Task. These results suggest that cocaine-taking in rested subjects is associated with some cognitive enhancement.

A laboratory model of cocaine withdrawal in humans: intravenous cocaine

Seven adult intravenous (IV) cocaine users completed a protocol investigating changes in behavior after the self-administration of cocaine. During sessions, the participants could self-administer up to 6 doses of IV cocaine (32 mg/70 kg) twice each day. Both 2- and 3-day binge conditions were tested. At 39 hr after the 3-day but not the 2-day binge of cocaine use, total Beck Depression Inventory scores were increased and participants reported increased ratings of Irritable and decreased ratings of I Want Cocaine. Exposure to stimulus cues associated with IV cocaine increased ratings of I Want Cocaine during periods of abstinence after both 2- and 3-day binges and increased ratings of Depressed only after the 3-day binge of cocaine use. The cessation of binge cocaine use produced modest changes in mood and cocaine craving that were related to the length of the binge and varied as a function of time since last cocaine use. Responsiveness to cocaine cues also varied as a function of the length of the previous cocaine binge.

An HIV type 1 epidemic among injecting drug users in the former Soviet Union caused by a homogeneous subtype A strain

Epidemiological data have demonstrated rapid growth of HIV-1 infections among injecting drug users (IDUs) in the Ukraine and Russia, during 1996. Here we describe the results of genetic analysis of isolates derived from 12 HIV-1-infected IDUs in different sites of Russia and the Ukraine. The blood samples were taken within a 1- to 2-month period after the first HIV-1-positive test. The results of the heteroduplex mobility assay as well as gag/env phylogenetic analysis reveal that all sequences belong to gag/env genetic subtype A. Moreover, interpatient genetic distances between the nucleotide sequences encompassing the C2-V3, the V4-V5, and p17-encoding regions within this group were low (the average means were 0.9, 1.3, and 0.4%, respectively). These data show a marked homogeneity of HIV-1, probably spreading during primary infection. It is possible that the current epidemic of subtype A HIV-1 among IDUs in the former Soviet Union is caused by a point source exposure.

Sexuality in Montreal women living with HIV

The impact of learning a positive HIV test result on the sexuality of 161 women (47 injection drug users (IDU), 53 non-IDU women of Haitian or African origin (non-IDU-HA), and 61 non-IDU Caucasian women (non-IDU-C) was assessed using closed and open-ended questions. Self-reported CD4+ count correlated with any post-test (p = 0.001) and past month sexual activity (p = 0.007). After learning their HIV status, 110 women (68%) were sexually active, 48 (44%) of these within 1 month. After resuming sexual activity, 84% underwent a sexual adjustment period (median duration 8.5 months). IDU women were more likely to have frequent sex, be anorgasmic, and prefer sex less often. Consistent partner condom use was low in general (19% for IDU, 30% for non-IDU-HA, and 62% for non-IDU-C) and by partner type (new regular partner 58%, same regular partner 36%, casual partner 29%). Sexual satisfaction tended to decline post-test and then increase to higher than pre-test levels. Counselling focused on the safe and satisfying aspects of sex may assist women with HIV infection in sexual decision-making. Facilitating the access of IDU women with HIV infection to medically supervised drug provision and to detoxification and rehabilitation programmes can weaken the link between drug use and sex work.

Oral candidiasis in HIV infection: predictive value and comparison of findings in injecting drug users and homosexual men

The objectives of this study were to compare the relationship of oral candidiasis to HIV status, cohort and CD4+ lymphocyte values in injecting drug users and homosexual men and to examine its impact on prognosis. An oral examination was added to an ongoing longitudinal study of HIV infection. Data obtained at 6-month intervals included smoking, illicit drug use, medication use, symptoms and medical diagnoses, physical examination findings and laboratory data. In this study HIV+ subjects were much more likely to present with oral candidiasis than were HIV- subjects (OR = 6.3, P < 0.01). Injecting drug users, regardless of serostatus, were more likely than homosexual men to present with oral candidiasis (OR = 3.0, P = 0.001). In both cohorts oral candidiasis was associated with low CD4+ lymphocyte counts and percent ages, and Kaplan-Meier survival estimates showed that subjects with oral candidiasis had a poorer prognosis than those without candidiasis, even after controlling for CD4+ lymphocyte count.

Event-related potential changes in cocaine withdrawal: evidence for long-term cognitive effects

The effects of cocaine withdrawal on the latency of the P300 cognitive event-related potential were studied in 36 subjects. All subjects had used cocaine within 48 h of admission to an inpatient unit. P300 was recorded in a traditional auditory oddball paradigm 2 and 6 days following admission. P300 latency decreased from day 2 to day 6 in subjects with a history of intravenous use, but was unchanged in subjects who had only used cocaine orally. The neurotransmitter systems mediating this effect, and the differential cognitive effects of route of administration are discussed.

[Peripheral nerve and spinal cord complication in intravenous heroin addiction]

The neurological complications observed in 6 HIV negative intravenous drug users are reported. Four developed acute neuromuscular involvement in a lumbosacral or brachial distribution with rhabdomyolysis, myoglobinuria, hypovolemia, renal and hepatic failure in the 3 most severely affected patients. Despite evidence of immunologic abnormalities and especially presence of anti-heroin antibodies, we feel that causative mechanisms include mixed compression and ischemia with an underlying toxic myopathy, resulting in segmental myopathy with secondary compression of peripheral nerves. Two patients developed myelopathy with acute or chronic onset. The mechanisms were vascular with spinal cord infarction in the acute form and probably infectious with secondary compressive arachnoiditis in the chronic form. In these 2 patients with myelopathy, outcome was poor.

Cocaine, dopamine and the endogenous opioid system

Cocaine addiction and opiate addiction are both major health problems in the United States today. Prospective studies from our Laboratory, which were able to detect the advent of the HIV-1 epidemic in parenteral drug abusers in New York City beginning around 1978, also showed that, from the beginning of the AIDS epidemic, cocaine abuse was a very important co-factor significantly increasing the risk for developing cocaine dependency. Fundamental studies from many laboratories including our own have shown that cocaine has profound effects on dopaminergic function, primarily from its well-established primary action of blocking the reuptake of dopamine from the synaptic cleft, an action of cocaine directed at the specific dopamine transporter. It has also been well-established by others that cocaine similarly blocks the reuptake of serotonin and norepinephrine. However, recent studies from our laboratory have shown that chronic cocaine administration profoundly disrupts the endogenous opioid system. Extensive studies have been conducted using an animal model which we have developed in our laboratory, the "binge" pattern cocaine administration model. Findings from these studies have led us to recognize the profound disruption of both dynorphin gene expression and kappa opioid receptor gene expression in a setting of chronic cocaine administration and, in turn, have led us to question a possible role of disruption of this system in the acquisition and persistence of cocaine addiction. These findings may have significance for the development of new pharmacotherapeutic agents which may be directed to specific components of the endogenous opioid system and, in particular, possibly the kappa opioid receptor system. Therefore, we have initiated studies to examine further the role of the dynorphin peptide-kappa opioid receptor system in normal physiologic function in humans.

Weight loss associated with HIV seroconversion among injection-drug users

To describe symptoms associated with human immunodeficiency virus (HIV) seroconversion, we studied a cohort of 366 injection-drug users (IDUs) with a study design that included recall every 3 months to collect symptom histories using a structured questionnaire. Eleven HIV seroconversions were observed in 621.5 person years at risk (PYAR), equivalent to 1.8 seroconversions/100 PYAR. Cox regression analysis showed age < or = 35 years to be a significant risk factor for HIV seroconversion after controlling for gender, race, and the frequency of drug injection. An embedded case-control analysis then compared symptom histories of HIV seroconverters with those of age-(+/- 5 years) and visit number-matched controls who remained HIV seronegative for > or = 3 months longer than the HIV-seroconverters. Multivariate case-control analysis adjusted for injection frequency yielded significant associations of HIV seroconversion with histories of weight loss > or = 4.5 kg (seven of 11 cases; odds ratio [OR] = 11.6, 95% confidence interval [CI] 3.1, 43.1) and oral ulcers (three of 11 cases; OR = 7.6, 95% CI = 1.2, 48.2) in the 3 months before the subjects' first HIV-seropositive study visit. We conclude that histories of recent symptoms reported by HIV-seroconverting IDUs differ from those reported by non-HIV-seroconverting IDUs, and weight loss may be particularly common among IDUs experiencing primary HIV infection.

Doubling skeletal mass during adult life: the syndrome of diffuse osteosclerosis after intravenous drug abuse

A former intravenous substance abuser, seropositive for hepatitis C virus infection, was referred for diffuse osteosclerosis. There was no history of fracture or skeletal deformity. Cortical and trabecular bone density was approximately twice the mean value for controls. Skeletal histology revealed dense lamellar bone. Recognized causes of acquired generalized osteosclerosis or hyperostosis were excluded. This patient verifies the syndrome of painful diffuse osteosclerosis after intravenous drug abuse and shows that skeletal mass can be markedly increased with histologically normal, structurally sound bone during adult life. Elucidation of the etiology and pathogenesis could offer an effective treatment for osteoporosis.

Consistency of repeated event-related potentials in clinically stable HIV-1-infected drug users

This study investigated the stability over time of delays in auditory event-related potentials (ERPs) caused by HIV-1 infection of the brain. ERPs were recorded at two time points from 17 former parenteral drug users (PDUs) and 8 non-PDU control subjects. There was no significant effect of time, and peak measures for the two visits were significantly correlated with each other. For both visits, N1 was delayed only for the seropositive stage IV subjects, whereas N2 was delayed for both seropositive groups. Group differences remained stable, confirming previously reported studies.

The 90K tumor-associated antigen and clinical progression in human immunodeficiency virus infection

We investigated the possibility that a secreted glycoprotein of approximately 90,000 daltons, termed 90K and identified as a member of the protein superfamily characterized by the scavenger receptor cysteine-rich (SRCR) domain, might have value as a predictor of progression to acquired immunodeficiency syndrome (AIDS) in subjects infected with the human immunodeficiency virus (HIV). Among 488 HIV-seropositive intravenous drug users with a median follow-up of 32.5 months, high levels of serum 90K at baseline proved to be a significant predictor of faster progression to AIDS, either as a continuous variable (log 90K; p < 0.0001) or as a dichotomous variable with an optimized cutoff point of 30 U/ml (p < 0.00001). Analysis of 90K in relation to known prognostic factors found an association with CD4 count, beta 2-microglobulin, and p24 antigen but none with neopterin. In multivariate analysis, the baseline 90K level was an independent predictor of AIDS. As compared with subjects with low levels of 90K, the relative risk of developing AIDS was 3.5 (95% CI 1.9-6.5) among those with high levels of 90K. The predictive value of 90K was maintained after stratification by baseline CD4 count: among subjects with > or = 500 x 10(6)/L CD4 cells, the proportion in whom AIDS developed was 10.5% for those with 90K levels < or = 30 U/ml as compared with 20% for those with 90K above the cutoff point (p = 0.006). Serum 90K is an independent predictor of the risk for progression to AIDS in HIV-infected subjects, including those whose CD4 counts have not fallen.