In vivo induction of human immunodeficiency virus type 1 entry into nucleus-free cells by CD4 gene transfer to hematopoietic stem cells: a hypothetical possible strategy for therapeutic intervention

As a useful alternative to employing soluble CD4 to inhibit binding of human immunodeficiency virus type 1 (HIV-1) to target cells, the introduction of CD4-bearing erythrocyte has been proposed by two study groups (see Refs. (5,6)). Prominently, Nicolau and colleagues demonstrated that the electroinserted CD4 molecules in the membranes of erythrocytes are capable of mediating HIV-1 entry. The implications of the studies are that inactivation of the integration-dependent retrovirus by the facilitation of entry into the nucleus-free cells, referred to as 'fake host trap' or 'host cell decoy', may be a possible therapeutic approach. Here we expand this concept to include genetic modification of autologous hematopoietic stem cells and review the relevant theoretical basis. Effective application of molecular technologies to induce partial replacement of hematopoiesis may be critical for this strategy.

The genetics of tobacco use: methods, findings and policy implications

Research on the genetics of smoking has increased our understanding of nicotine dependence, and it is likely to illuminate the mechanisms by which cigarette smoking adversely effects the health of smokers. Given recent advances in molecular biology, including the completion of the draft sequence of the human genome, interest has now turned to identifying gene markers that predict a heightened risk of using tobacco and developing nicotine dependence

Molecular evidence of mother-to-child transmission of HTLV-IIc in the Kararao Village (Kayapo) in the Amazon region of Brazil

Blood samples from native Indians in the Kararao village (Kayapo), were analysed using serological and molecular methods to characterize infection and analyse transmission of HTLV-II. Specific reactivity was observed in 3/26 individuals, of which two samples were from a mother and child. RFLP analysis of the pX and env regions confirmed HTLV-II infection. Nucleotide sequence of the 5' LTR segment and phylogenetic analysis showed a high similarity (98%) between the three samples and prototype HTLV-IIa (Mot), and confirmed the occurrence of the HTLV-IIc subtype. There was a high genetic similarity (99.9%) between the mother and child samples and the only difference was a deletion of two nucleotides (TC) in the mother sequence. Previous epidemiological studies among native Indians from Brazil have provided evidence of intrafamilial and vertical transmission of HTLV-IIc. The present study now provides molecular evidence of mother-to-child transmission of HTLV-IIc, a mechanism that is in large part responsible for the endemicity of HTLV in these relatively closed populations. Although the actual route of transmission is unknown, breast feeding would appear to be most likely.

Alcohol, cannabis and tobacco use among Australians: a comparison of their associations with other drug use and use disorders, affective and anxiety disorders, and psychosis

AIM

To compare relationships between alcohol, cannabis and tobacco and indicators of mental health problems in the general population.

METHOD

A survey of a nationally representative sample of 10 641 Australian adults (the National Survey of Mental Health and Well-Being (NSMHWB)) provided data on alcohol, cannabis and tobacco use and mental health (DSM-IV anxiety disorders, affective disorders, other substance use disorders and screening positively for psychosis).

FINDINGS

Alcohol showed a "J-shaped" relationship with DSM-IV affective and anxiety disorders: alcohol users had lower rates of these problems than non-users of alcohol, while those meeting criteria for alcohol dependence had the highest rates. Tobacco and cannabis use were both associated with increased rates of all mental health problems examined. However, after controlling for demographics, neuroticism and other drug use, cannabis was not associated with anxiety or affective disorders. Alcohol dependence and tobacco use remained associated with both of these indicators of mental health. All three types of drug use were associated with higher rates of other substance use problems, with cannabis having the strongest association.

CONCLUSIONS

The use of alcohol, tobacco and cannabis are associated with different patterns of co-morbidity in the general population.

The relationship between cannabis use and other substance use in the general population

This study examined if (1) there is an association in the general population between cannabis use, DSM-IV abuse and dependence, and other substance use and DSM-IV substance abuse/dependence; (2) if so, is it explained by demographic characteristics or levels of neuroticism? It used data from the Australian National Survey of Mental Health and Well-Being (NSMHWB), a stratified, multistage probability sample of 10,641 adults, representative of the general population. DSM-IV diagnoses of substance abuse and dependence were derived using the Composite International Diagnostic Interview (CIDI). There was a strong bivariate association between involvement with cannabis use in the past 12 months and other substance use, abuse and dependence. In particular, cannabis abuse and dependence were highly associated with increased risks of other substance dependence. These associations remained after including other variables in multiple regression. Cannabis use without disorder was strongly related to other drug use, an association that was not explained by other variables considered here. The high likelihood of other substance use and substance use disorders needs to be considered among persons seeking treatment for cannabis use problems.

Ambulance calls to suspected overdoses: New South Wales patterns July 1997 to June 1999

AIM

Using data on New South Wales ambulance calls to suspected overdoses from July 1997 to June 1999 to: a) examine temporal and geographic trends in calls; and b) compare geographic patterns of fatal and non-fatal opioid overdose.

METHOD

The NSW Ambulance Service provided data on the occasions when an ambulance attended a person on whom the drug overdose/poisonings protocol was used, and to whom naloxone was administered. The geographic distribution of ambulance attendances was approximated to the Australian Bureau of Statistics Statistical Local Area (SLA) and Statistical Subdivision (SSD). Estimates of social disadvantage were correlated with the rate of ambulance attendances for each region.

RESULTS

9,116 callouts were made. In cases with data on age and gender, 89% were aged 15-44 years, and 31% were female. South Sydney (n=1,819) and Liverpool (n=1,602) SLAs accounted for 37% of calls; the higher rates outside Sydney were in Newcastle, Orange and Kiama. There was a strong correlation between rates of ambulance callouts and fatal heroin overdoses. The number of calls increased from an average of 361 calls per month in 1997-98 to 399 in 1998-99. The majority of calls (54%) were made between midday and 9 pm.

CONCLUSIONS

Rates of ambulance attendance at suspected overdoses is a promising indicator that allows monitoring of trends and identification of areas with high rates of opioid use.

Pilot randomized controlled study of dexamphetamine substitution for amphetamine dependence

AIMS

To test the feasibility of conducting a definitive randomized controlled trial of dexamphetamine substitution for amphetamine dependent people and provide preliminary data.

DESIGN

An open, two-group pre-post randomized controlled trial.

PARTICIPANTS

Forty-one long-term, dependent amphetamine users seeking treatment.

INTERVENTION

Twenty subjects were offered weekly counselling. Twenty-one subjects were, in addition, prescribed up to 60 mg dexamphetamine daily.

MEASUREMENTS

Immunoassay and mass spectrometric urinalysis techniques were used to identify the presence of amphetamine and methylamphetamine in urine. The Opiate Treatment Index and Severity of Dependence Scale were used to collect pre- and post-self-report data. Subjects were screened using the Composite International Diagnostic Interview.

FINDINGS

Reduced street amphetamine use and amphetamine dependence was observed both in subjects prescribed dexamphetamine and subjects receiving counselling only. Treatment subjects appeared more likely to attend counselling.

CONCLUSIONS

A definitive randomized controlled trial of dexamphetamine substitution using the techniques and instruments piloted in this study is feasible. Users appeared to be attracted and retained in substitution treatment. The intervention also appeared to be acceptable to clinicians.

Challenges and approaches to estimating mortality attributable to the use of selected illicit drugs

A number of unique challenges are faced when attempting to estimate mortality attributable to illicit drugs. The hidden nature of illicit drug use creates difficulties in quantifying the prevalence of such use; identifying adverse health effects associated with exposure, and calculating the risk of these effects. The use of cohort studies of drug users allows the identification of causes of mortality associated with drug use and the determination of the risk of these causes. This risk estimate can then be used in conjunction with estimates of the prevalence of drug use to extrapolate the burden of mortality. We identify a number of such studies and present some solutions to the major challenges faced when attempting to estimate the global burden of mortality attributable to illicit drug use.

Heroin overdose: causes and consequences

Over the past decade fatal opioid overdose has emerged as a major public health issue internationally. This paper examines the risk factors for overdose from a biomedical perspective. While significant risk factors for opioid overdose fatality are well recognized, the mechanism of fatal overdose remains unclear. Losses of tolerance and concomitant use of alcohol and other CNS depressants clearly play a major role in fatality; however, such risk factors do not account for the strong age and gender patterns observed consistently among victims of overdose. There is evidence that systemic disease may be more prevalent in users at greatest risk of overdose. We hypothesize that pulmonary and hepatic dysfunction resulting from such disease may increase susceptibility to both fatal and non-fatal overdose. Sequelae of non-fatal overdose are recognized in the clinical literature but few epidemiological data exist describing the burden of morbidity arising from such sequelae. The potential for overdose to cause persisting morbidity is reviewed.

The relationship between tobacco use, substance-use disorders and mental health: results from the National Survey of Mental Health and Well-being

AIMS

To examine comorbidity between tobacco use, substance-use disorders and mental health problems among Australian adults aged 18 years and over.

METHOD

Data from the 1997 Australian National Survey of Mental Health and Well-being were analyzed. This survey was a stratified, multistage probability sample of 10,641 adults, representative of the Australian population. Univariate associations between tobacco use, substance use and mental health were examined, and then multivariate analyses were conducted to control for demographic characteristics, neuroticism, and other drug use.

MEASUREMENTS

Tobacco use status was defined as: never smoker, former smoker and current smoker. DSM-IV diagnoses of substance use, anxiety, and affective disorders were derived using the Composite International Diagnostic Interview (CIDI). Other measures included a screener for psychosis and measures of psychological distress and disability.

FINDINGS

Current tobacco use was strongly associated with abuse/dependence upon alcohol, cannabis, and other substances, and with higher rates of anxiety and affective disorders. Current smokers were more likely to screen positively for psychosis and reported greater psychological distress and disability than non-smokers and never smokers. These higher rates of other problems were not explained by differences in demographic characteristics, neuroticism scores, or by other drug use. Former smokers did not have higher rates of affective or anxiety disorders; however, they had higher rates of alcohol-use disorders, and of cannabis-use disorders after adjusting for covariates.

CONCLUSIONS

Current tobacco use is associated with a range of other substance-use and mental health problems. These are likely to reduce the success of attempts to quit smoking. The presence of these other problems needs to be considered when considering smoking-cessation treatment, and further research may provide information on more effective treatment strategies for persons with co-existing substance-use and mental health problems.

Characteristics of DSM-IV and ICD-10 cannabis dependence among Australian adults: results from the National Survey of Mental Health and Wellbeing

A representative sample (n = 10641) of Australian adults completed a structured diagnostic interview assessing the prevalence of mental and substance use disorders in the last year. The prevalence of DSM-IV (1.5%) and ICD-10 (1.7%) cannabis dependence was similar. DSM-IV and ICD-10 dependence criteria comprised unidimensional syndromes. The most common symptoms among dependent and non-dependent users were difficulties with controlling use and withdrawal, although there were marked differences in symptom prevalence. Dependent users reported a median of four symptoms. There was good to excellent diagnostic concordance (kappas = 0.7-0.9) between systems for dependence but not for abuse/harmful use (Y = 0.4). These findings provide some support for the validity of cannabis dependence.

Attention deficit hyperactivity disorder and substance use disorders: Is there a causal link?

Attention-deficit hyperactivity disorder (ADHD), characterized by restless, inattentive and hyperactive behaviours, is a relatively common childhood disorder that affects approximately 5% of the general population. There has been controversy about whether ADHD increases risks of developing substance use disorders. The available evidence suggests that, in the absence of conduct disorder, ADHD is not associated with an increased risk of substance use problems in males. There is only limited evidence on the role of ADHD in the aetiology of substance use disorders among females. While ADHD has traditionally been considered as a childhood disorder, it may also occur in adults; research needs to examine the extent to which ADHD in adulthood increases the risk of substance use disorders.

The relationship between cannabis use, depression and anxiety among Australian adults: findings from the National Survey of Mental Health and Well-Being

BACKGROUND

This study aimed to examine the patterns of association between cannabis use, and anxiety and affective disorders, in the general population.

METHOD

Data from the Australian National Survey of Mental Health and Well-Being, a representative survey of Australians aged 18 years and over, were analysed to address the following questions: (1) is there an association between cannabis use, DSM-IV abuse and dependence, and DSM-IV affective and anxiety disorders; (2) if so, is it explained by: demographic characteristics, levels of neuroticism, or other drug use; and (3) does the presence of a comorbid affective or anxiety disorder affect the likelihood of treatment seeking among cannabis users?

RESULTS

There was a moderate univariate association between involvement with cannabis use in the past 12 months and the prevalence of affective and anxiety disorders. Among those with DSM-IV cannabis dependence, 14% met criteria for an affective disorder, compared to 6% of non-users; while 17% met criteria for an anxiety disorder, compared to 5% of non-users. These associations did not remain significant after including demographics, neuroticism and other drug use in multiple regressions.

CONCLUSIONS

Cannabis use did not appear to be directly related to depression or anxiety when account was taken of other drug use. However, the association between heavier involvement with cannabis use and affective and anxiety disorders has implications for the treatment of persons with problematic cannabis use.

Cannabis use and dependence among Australian adults: results from the National Survey of Mental Health and Wellbeing

AIMS

To examine: (i) the prevalence of cannabis use and DSM-IV cannabis dependence among Australian adults, and (ii) correlates of level of cannabis involvement.

DESIGN

Cross-sectional survey assessing substance use and DSM-IV substance use disorders (abuse and dependence). Setting and participants. A household survey of a nationally representative sample of 10 641 Australians aged 18 years and older.

MEASUREMENTS

Trained interviewers administered a structured, modified version of the Composite International Diagnostic Interview (CIDI).

FINDINGS

In the past 12 months, 2.2% (95%CI:1.8, 2.6) of adults were diagnosed with DSM-IV cannabis use disorder, comprising cannabis dependence (1.5%; 95%CI: 1.2, 1.8) and cannabis abuse (0.7%, 95%CI: 0.6, 0.8). Almost one-third of cannabis users (31.7%; 95%CI: 27.7, 35.7) met criteria for cannabis dependence (21%; 95%CI: 16.7, 25.3) and abuse (10.7%; 95%CI: 8.0, 13.4). Multinomial logistic regression revealed that compared to non-dependent cannabis users, non-users were more likely to be female, aged 25 + years, out of the labour force and married/de facto, and displayed lower levels of co-morbidity. In contrast, dependent cannabis users were more likely to be 18-24 years old, unemployed, and displayed higher levels of co-morbidity than non-dependent users.

CONCLUSIONS

Cannabis use disorders affect approximately 300 000 Australian adults. A better understanding of the factors associated with cannabis dependence may help identify groups who have difficulties controlling use and aid the development of strategies for reducing cannabis-related harm.

Reducing the harms caused by cannabis use: the policy debate in Australia

The debate about cannabis policy in Australia has revolved around the harms that cannabis causes to users and the community, on the one hand, and the harms that are caused by the prohibition of its use, on the other. This paper assesses evidence on: (1) the harms caused to users and the community by cannabis use (derived from the international scientific literature) and (2) the harms that arise from prohibition (as reflected in Australian research). The most probable harms caused by cannabis use include: an increased risk of motor vehicle accidents; respiratory disease; dependence; adverse effects on adolescent development; and the exacerbation of psychosis. The harms of the current prohibition on cannabis use policy are less tangible but probably include: the creation of a large blackmarket; disrespect for a widely broken law; harms to the reputation of the unlucky few cannabis users who are caught and prosecuted; lack of access to cannabis for medical uses; and an inefficient use of law enforcement resources. Cannabis policy unavoidably involves trade offs between competing values that should be made by the political process. Australian cannabis policy has converged on a solution which continues to prohibit cannabis but reduces the severity of penalties for cannabis use by either removing criminal penalties or diverting first time cannabis offenders into treatment and education.

The association between psychosis and problematical drug use among Australian adults: findings from the National Survey of Mental Health and Well-Being

BACKGROUND

The present paper aimed to: (a) provide Australian estimates of the population-level association between psychotic 'caseness' and substance use; (b) examine liability to problematical substance use according to 'caseness' via the conditional prevalence (prevalence among users); and (c) examine associations between problematical substance use and the number of psychotic symptoms using ordinal logistic regression.

METHOD

Data were from the National Survey of Mental Health and Well-Being (NSMHWB), a stratified multi-stage probability sample of Australian adults, using a subset of persons under the age of 50 years (N = 6722). A screener assessed the presence of characteristic psychotic symptoms. Associations between 'case' status and DSM-IV alcohol, cannabis and other drug use disorders were examined. Ordinal logistic regressions predicting psychosis scores were carried out, including demographic, mental health and drug use variables.

RESULTS

Ninety-nine persons (1.2%) screened positively for psychosis. Regular tobacco, alcohol and cannabis use were much more common among persons screening positively, as were alcohol, cannabis and other drug use disorders. Among alcohol and cannabis users, psychosis 'cases' were much more likely to be dependent. Ordinal logistic regressions revealed that regular tobacco use, cannabis and alcohol dependence, and opiate abuse were predictors of psychosis scores.

CONCLUSIONS

The mental health risks of problematical substance use need to be disseminated to persons at risk of, or suffering from, psychotic illness, and to heavy substance users. Work is needed to develop effective treatment approaches for problematical substance use among persons with psychosis.

Antenatal hepatitis B screening - is there a need for a national policy?

Routine antenatal testing for hepatitis B carriage with maternal consent was introduced at the Rotunda in January 1998. The uptake of testing has been excellent; 99.98% of women presenting for antenatal care accepted hepatitis B (HBV) screening in the 30-months from January 1998 through June 2000. The prevalence of HBV carriage was 0.35% (58 pregnancies of 16,222 tested) increasing from 0.25% in 1998 (16 of 6227) to 0.45% in the first six months of 2000 (16 of 3484). Fifty-five women had 58 pregnancies (three women had two pregnancies). Two of these were e-antigen positive. HBV carrier status was previously unknown in 48 (87%). Two additional women had acute HBV infection in pregnancy. Forty-five infants have been born to mothers included in this screening programme. Audit of infant outcome reveals excellent compliance with immunisation and follow-up: 29 (64%) have completed the 3 dose HBV vaccination schedule to date. Thirteen infants (31%) are still attending; three are lost to follow-up including one whose family has emigrated. Routine antenatal screening for hepatitis B carriage is cost-effective and should be considered a standard of care in maternity practice.

Outcome of infants born to hepatitis C infected women

BACKGROUND

Hepatitis C virus (HCV) can be transmitted vertically from mother to infant, either late in pregnancy or at delivery.

AIMS

To determine the outcome of infants born to HCV infected women, to characterise epidemiology and to design an appropriate infant monitoring schedule.

METHODS

Three hundred and fourteen infants, born to 296 HCV positive women between 1994 and 1999 were monitored for a median of 18 months (range 1-52).

RESULTS

Forty per cent of infants were small for age and 46% had neonatal abstinence syndrome (NAS). Of 173 infants of defined status, 11 were infected (vertical transmission rate [VTR] 6.4%, 95% CI 2.8-10). Infected infants were diagnosed at a median of three months (range 0.5-10). Liver transaminases elevation was documented in 8% of uninfected infants. A negative HCV PCR test before one month of age did not exclude infection but all infected patients had detectable HCV RNA when next tested (range 2-10 months).

CONCLUSIONS

94% of infants born to HCV antibody positive women are not HIV infected. Liver transaminase elevation in exposed infants is not always indicative of infection. A minimum monitoring schedule of testing (PCR and antibody) at six to eight weeks, six and 18 months allows early diagnosis while detecting late seroconversions.

Laboratory guidelines for the practical use of HIV drug resistance tests in patient follow-up

HIV drug resistance is one of the major limitations in the successful treatment of HIV-infected patients using currently available antiretroviral combination therapies. When appropriate, drug susceptibility profiles should be taken into consideration in the choice of a specific combination therapy. Guidelines recommending resistance testing in certain circumstances have been issued. Many clinicians have access to resistance testing and will increasingly use these results in their treatment decisions. In this document, we comment on the different methods available, and the relevant issues relating to the clinical application of these tests. Specifically, the following recommendations can be made: (i) genotypic and phenotypic HIV-1 drug resistance analyses can yield complementary information for the clinician. However, insufficient information currently exists as to which approach is preferable in any particular clinical setting; (ii) when HIV-1 drug resistance testing is required, it is recommended that testing be performed on plasma samples obtained before starting, stopping or changing therapy, on samples that have a viral load above the detection limit of the resistance test; (iii) the panel recommends that genotypic and phenotypic HIV-1 drug resistance testing for clinical purposes be performed in a certified laboratory under strict quality control and quality assurance standards; and (iv) the panel recommends that resistance testing laboratories provide clinicians with resistance reports that include a list of drug-related resistance mutations (genotype) and/or a list of drug-related fold resistance values (phenotype), with interpretations of each by an experienced virologist. The interpretation of genotypic and phenotypic analysis is a complex and developing science, and in order to understand HIV-1 drug resistance reports, communication between the requesting clinician and the expert that interpreted the resistance report is recommended.