Back-projection estimates of the number of dependent heroin users in Australia

AIMS

To plan an appropriate response to heroin use in Australia, good estimates are needed of the numbers of dependent heroin users, the group who are most in need of treatment, most at risk of fatal opioid overdose and most at risk of contracting and transmitting blood-borne viruses.

METHODS

Back-projection methods were used to estimate the numbers of people starting dependent heroin injecting in Australia between 1960 and 1997. Separate analyses were based on national opioid overdose deaths and numbers of new entrants to methadone treatment in New South Wales (NSW). Estimates of the rates at which dependent heroin users cease heroin use, commence methadone treatment or die from opioid overdoses were estimated from external data sources.

RESULTS

Back-projection estimates derived from opioid overdose deaths indicated that there were 104 000 (lower limit of 72 000 and upper limit of 157 000) people who were heroin dependent in Australia between 1960 and 1997. Of these it was estimated that 67 000 (39 000-120 000) were still heroin dependent at the end of 1997. Back-projection estimates based on numbers of new entrants to methadone treatment in NSW indicated that there were 108 000 (82 000-141 000) heroin-dependent people in Australia between 1960 and 1997, of whom 71 000 (47 000-109 000) were estimated to be heroin dependent at the end of 1997. Both analyses indicated that the number of heroin-dependent people in Australia has increased substantially from the early 1970s onwards.

CONCLUSIONS

Back-projection estimates based on analyses of treatment entries and opioid overdose deaths provide an additional method for estimating the numbers of heroin-dependent people in the population. The addition of these methods to existing methods, using different data sources and statistical methods, should improve consensus estimates of the numbers of heroin-dependent people.

Dating the common ancestor of SIVcpz and HIV-1 group M and the origin of HIV-1 subtypes using a new method to uncover clock-like molecular evolution

Attempts to estimate the time of origin of human immunodeficiency virus (HIV)-1 by using phylogenetic analysis are seriously flawed because of the unequal evolutionary rates among different viral lineages. Here, we report a new method of molecular clock analysis, called Site Stripping for Clock Detection (SSCD), which allows selection of nucleotide sites evolving at an equal rate in different lineages. The method was validated on a dataset of patients all infected with hepatitis C virus in 1977 by the same donor, and it was able to date exactly the known origin of the infection. Using the same method, we calculated that the origin of HIV-1 group M radiation was in the 1930s. In addition, we show that the coalescence time of the simian ancestor of HIV-1 group M and its closest related cpz strains occurred around the end of the XVII century, a date that could be considered the upper limit to the time of simian-to-human transmission of HIV-1 group M. The results show also that SSCD is an easy-to-use method of general applicability in molecular evolution to calibrate clock-like phylogenetic trees.

Prevalence, comorbidity, disability and service utilisation. Overview of the Australian National Mental Health Survey

BACKGROUND

Health planning should be based on data about prevalence, disability and services used.

AIMS

To determine the prevalence of ICD-10 disorders and associated comorbidity, disability and service utilisation.

METHOD

We surveyed a national probability sample of Australian households using the Composite International Diagnostic Interview and other measures.

RESULTS

The sample size was 10 641 adults, response rate 78%. Close to 23% reported at least one disorder in the past 12 months and 14% a current disorder. Comorbidity was associated with disability and service use. Only 35% of people with a mental disorder in the 12 months prior to the survey had consulted for a mental problem during that year, and most had seen a general practitioner. Only half of those who were disabled or had multiple comorbidity had consulted and of those who had not, more than half said they did not need treatment.

CONCLUSIONS

The high rate of not consulting among those with disability and comorbidity is an important public health problem. As Australia has a universal health insurance scheme, the barriers to effective care must be patient knowledge and physician competence.

The tripeptide glycyl-prolyl-glycine amide does not affect the early steps of the human immunodeficiency virus type 1 replication

OBJECTIVE

To determine whether the peptide glycyl-prolyl-glycine amide (GPG-NH2) corresponding to a conserved motif in the tip of the third hypervariable region of gp120 affected the early events in the human immunodeficiency virus type 1 (HIV-1) replication.

DESIGN/METHODS

Glycyl-prolyl-glycine amide was tested for its effect on HIV-1 adsorption, co-receptor usage, proviral DNA synthesis, messenger RNA (mRNA) synthesis and splicing, translation, tat/TAR transactivation, and virus protease activity.

RESULTS

Glycyl-prolyl-glycine amide did not appear to affect the early events of the virus replication. HIV-1 having glycine-leucine-glycine instead of GPG in the V3 loop and the mutants deleted of the GPG motif were still inhibited by the peptide. Glycyl-prolyl-glycine-NH2 had no discernible effect on any of the other steps in the virus replication cycle tested. The only effect observed was an increased sodium dodecyl sulfate polyacrylamide amide gel electrophoresis mobility of gp160/120 at high concentrations of GPG-NH2.

CONCLUSIONS

The tripeptide GPG-NH2 is a nontoxic compound that inhibits the replication of HIV-1 by an apparently new mode of action.

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.

Impact of increasing the re-supply interval on the seasonality of subsidised prescription use in Australia

OBJECTIVE

To evaluate the impact of increasing the minimum re-supply period for prescriptions on the Pharmaceutical Benefits Scheme (PBS) in November 1994. The intervention was designed to reduce the stockpiling of medicines used for chronic medical conditions under the PBS safety net.

METHODS

Interrupted times series regression analyses were performed on 114 months of PBS drug utilisation data from January 1991 to June 2000. These analyses assessed whether there had been a significant interaction between the onset of the intervention in November 1994 and the extreme levels of drug utilisation in the months of December (peak utilisation) and January (lowest utilisation) respectively. Both serial and 12-month lag autocorrelations were controlled for.

RESULTS

The onset of the intervention was associated with a significant reduction in the December peak in drug utilisation; after the introduction of the policy there were 1,150,196 fewer prescriptions on average for that month (95% CI 708,333-1,592,059). There was, however, no significant change in the low level of utilisation in January. The effect of the policy appears to be decreasing across successive post-intervention years, though the odds of a prescription being dispensed in December remained significantly lower in 1999 compared to each of the pre-intervention years (11% vs. 14%).

CONCLUSION

Analysis of the impact of increasing the re-supply period for PBS prescriptions showed that the magnitude of peak utilisation in December had been markedly reduced by the policy, though this effect appears to be decreasing over time. Continued monitoring and policy review is warranted in order to ensure that the initial effect of the intervention be maintained.

The effects of adolescent cannabis use on educational attainment: a review

This paper reviews research examining the link between cannabis use and educational attainment among youth. Cross-sectional studies have revealed significant associations between cannabis use and a range of measures of educational performance including lower grade point average, less satisfaction with school, negative attitudes to school, increased rates of school absenteeism and poor school performance. However, results of cross-sectional studies cannot be used to determine whether cannabis use causes poor educational performance, poor educational performance is a cause of cannabis use or whether both outcomes are a reflection of common risk factors. Nonetheless, a number of prospective longitudinal studies have indicated that early cannabis use may significantly increase risks of subsequent poor school performance and, in particular, early school leaving. This association has remained after control for a wide range of prospectively assessed covariates. Possible mechanisms underlying an association between early cannabis use and educational attainment include the possibility that cannabis use induces an 'amotivational syndrome' or that cannabis use causes cognitive impairment. However, there appears to be relatively little empirical support for these hypotheses. It is proposed that the link between early cannabis use and educational attainment arises because of the social context within which cannabis is used. In particular, early cannabis use appears to be associated with the adoption of an anti-conventional lifestyle characterized by affiliations with delinquent and substance using peers, and the precocious adoption of adult roles including early school leaving, leaving the parental home and early parenthood.

Inactivation of p53 by HTLV type 1 and HTLV type 2 Tax trans-activators

Human T cell lymphotropic virus type II (HTLV-2) was originally isolated from a patient with a hairy T cell leukemia. It has been associated with rare cases of CD8(+) T lymphoproliferative disorders, and has a controversial role as a pathogen. The loss of p53 function, as a consequence of mutation or inactivation, increases the chances of genetic damage. Indeed, the importance of p53 as a tumor suppressor is evident from the fact that over 60% of all human cancers have a mutant or inactive p53. p53 status has been extensively studied in HTLV-1-infected cell lines. Interestingly, despite the fact that p53 mutations have been found in only a minority of cells, the p53 functions were found to be impaired. We have analyzed the functional activity of the p53 tumor suppressor in cells transformed with HTLV-2 subtypes A and B. As with HTLV-1-infected cells, abundant levels of the p53 protein are detected in HTLV-2 virus-infected cell lines. Using p53 reporter plasmid or induction of p53-responsive genes in response to gamma-irradiation, the p53 was found to be transcriptionally inhibited in HTLV-2-infected cells. Interestingly, although Tax-2A and-2B inactivate p53, the Tax-2A protein appears to inhibit p53 function less efficiently than either Tax-1 or Tax-2B in T cells, but not in fibroblasts.

Spontaneous production of C-C chemokines by individuals infected with human T lymphotropic virus type II (HTLV-II) alone and HTLV-II/HIV-1 coinfected individuals

To investigate the immunological features of human T lymphotropic virus type II (HTLV-II) infection and specific mechanisms whereby HTLV-II might influence the progression of HIV-1 disease in coinfected individuals, we have analyzed the production of the C-C chemokines RANTES and macrophage inflammatory proteins 1alpha and 1alpha (MIP-1alpha and MIP-1beta) by PBMCs from HTLV-II-infected and HTLV-II/HIV-1-coinfected individuals. We observed spontaneous production of significant levels of MIP-1alpha and -1beta and, to a lesser extent, RANTES, from individuals infected with HTLV-II alone or with concomitant HIV-1 infection. Spontaneous C-C chemokine production was not observed in PBMCs from uninfected or HIV-1-infected individuals. Although HTLV-II is known to preferentially infect CD8+ lymphocytes in vivo, we observed that whereas RANTES was produced exclusively by the CD8+-enriched fraction, MIP-1alpha and -1beta were produced by both the CD8+-enriched and CD8+-depleted fractions of HTLV-II-infected PBMCs. RT-PCR demonstrated active expression of the HTLV-II regulatory protein Tax in the infected CD8+ T lymphocyte population, and it was further shown that Tax transactivates the promoters of MIP-1beta and RANTES. Therefore, it appears that HTLV-II stimulates the production of C-C chemokines both directly at a transcriptional level via the viral transactivator Tax and also indirectly. Although the HTLV-II-infected individuals in this study are all virtually asymptomatic, they certainly display an abnormal immune phenotype. Moreover, our findings suggest that HTLV-II, via chemokine production, would be expected to alter the progression of HIV-1 infection in coinfected individuals.

The THC content of cannabis in Australia: evidence and implications

OBJECTIVE

To examine evidence on three claims that: 1) the THC content of Australian cannabis plants has increased up to 30 times; 2) problems experienced by cannabis users have increased in Australia in recent years; and 3) an increase in THC content is the most likely explanation of any increase in cannabis-related problems.

METHODS

These claims were assessed by examining data: 1) on THC potency in Australia, the United States and New Zealand; 2) on cannabis-related problems; and 3) from the 1998 National Drug Strategy Household Survey on patterns of cannabis use.

RESULTS

1) Published data do not show a 30-fold increase in THC potency of cannabis but show a more modest increase in the US. 2) There is suggestive evidence of an increase in cannabis-related problems among people seeking treatment for alcohol and drug problems, juvenile offenders and young adults with psychosis. 3) There are two other more plausible explanations for these reportedly higher rates of cannabis-related problems among adolescents and young adults: (i) more potent forms of cannabis ('heads') are more widely used; and (ii) cannabis users are initiating cannabis at an earlier age, thereby increasing the prevalence of harmful patterns of use.

CONCLUSIONS

There has probably been a modest increase in the THC content of cannabis, but changing patterns of cannabis use have probably made a larger contribution to any increase in rates of cannabis-related problems among young Australian adults.

IMPLICATIONS

Better data on the THC content of cannabis, the extent of cannabis-related problems and the ability of users to titrate the dose of cannabis would contribute to more informed debate.

Differences in the ability of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 tax to inhibit p53 function

We have analyzed the functional activity of the p53 tumor suppressor in human T-cell lymphotropic virus type 2 (HTLV-2)-transformed cells. Abundant levels of the p53 protein were detected in both HTLV-2A and -2B virus-infected cell lines. The p53 was functionally inactive, however, both in transient-transfection assays using a p53 reporter plasmid and in induction of p53-responsive genes in response to gamma irradiation. We further investigated HTLV-2A Tax and HTLV-2B Tax effects on p53 activity. Interestingly, although Tax-2A and -2B inactivate p53, the Tax-2A protein appears to inhibit p53 function less efficiently than either Tax-1 or Tax-2B. In transient-cotransfection assays, Tax-1 and Tax-2B inactivated p53 by 80%, while Tax2A reduced p53 activity by 20%. In addition, Tax-2A does not increase the steady-state level of cellular p53 as well as Tax-1 or -2B does in the same assays. Cotransfection assays demonstrated that Tax-2A could efficiently transactivate CREB-responsive promoters to the same level as Tax-1 and Tax-2B, indicating that the protein was functional. This report provides evidence of the first functional difference between the HTLV-2A and -2B subtypes. This comparison of the action of HTLV-1 and HTLV-2 Tax proteins on p53 function will provide important insights into the mechanism of HTLV transformation.

Cohort trends in the age of initiation of drug use in Australia

AIM

To examine birth cohort trends in the prevalence of use and the age of initiation of use of: alcohol, tobacco, cannabis, amphetamines, LSD, and heroin.

METHOD

Data were taken from the 1998 National Drug Strategy Household Survey, a survey of a representative sample of Australians aged 14 years and over. Nine five-year cohorts were examined among persons born between 1940 and 1984. The weighted prevalence of use by ages 15 years, 21 years, and lifetime use, was estimated, as was the average age of first use among users. The significance of trends was tested using logistic regression (for lifetime use, use by 15 and 21 years) and linear regression (for age of first use).

RESULTS

Lifetime prevalence of alcohol and tobacco use was similar among all birth cohorts. The prevalence of illicit drug use--cannabis, amphetamines, LSD and heroin--increased with successive birth cohorts and more recent birth cohorts reported using licit and illicit drugs at a younger age.

CONCLUSIONS

More recent cohorts are more likely to use illicit drugs at some point in their lives. Greater numbers of persons from more recent birth cohorts may be at risk of developing substance-related problems.

Hepatitis C infection in an Irish antenatal population

BACKGROUND

Hepatitis C infection (HCV) has an estimated seroprevalence of 1-2% in women of child-bearing age and vertical transmission rate of 5-15%.

AIMS

To characterise the current trends of HCV in an Irish antenatal population.

METHODS

Infants of HCV seropositive women, born 1994 to 1999, were referred to the Paediatric Infectious Diseases service. Maternal details were collected retrospectively.

RESULTS

296 HCV seropositive women were studied. 244 (82%) were infected through intravenous drug use (IVDU), 25 (8%) through heterosexual contact and 13 (7%) via blood products. Nine women had no identifiable risk factors. Coinfection with other blood borne viruses was uncommon (4.7% HIV, 3.4% hepatitis B). Of 84 women tested for HCV-RNA, 46 (55%) were positive. Eighty three (26%) delivered prematurely; the caesarean section rate was 11%.

CONCLUSIONS

HCV is increasingly detected in antenatal clinics. Heterosexual contact is a mode of spread. Maternal HCV viraemia can be variable in pregnancy. Further study of HCV in pregnancy is needed to define the impact of pregnancy on HCV, accurately predict infant outcome and selectively target interventions to women at greatest risk of transmission.

Transcriptional activation of JC virus by human T-lymphotropic virus type I Tax protein in human neuronal cell lines

Polyomavirus JC (JCV) causes the human demyelinating disease, progressive multifocal leukoencephalopathy (PML). The recent demonstration of cases of PML in association with human T-lymphotropic virus type I (HTLV-I) infection prompted us to examine whether the HTLV-I-encoded regulatory protein Tax activates JCV transcription. By employing a dual luciferase assay, we initially found that the expression of Tax activated the transcriptional potential of both early and late promoters of JCV in human neuronal but not in non-neuronal cells. We subsequently analyzed the mechanism of Tax-induced activation of the JCV promoter in neuronal cells with the following results: 1) the JCV promoter that lacks the NF-kappaB-binding motif could not be activated by Tax; 2) the overexpression of IkappaBalpha abolished Tax-induced transcriptional activation of the JCV promoter; 3) a Tax mutant (M22) lacking the potential for activation via the NF-kappaB pathway did not activate the JCV promoter. Furthermore, Tax enhances the gene expression of JCV T antigen and VP1. We examined mechanisms of the cell-specific activation of the JCV promoter by Tax. Electrophoretic mobility shift assay demonstrated the presence of Tax-bound protein(s) that were specifically present in non-neuronal cells. This study is the first demonstration of the activation of JCV promoter by HTLV-I Tax in an NF-kappaB-dependent manner.

One year follow-up of cannabis dependence among long-term users in Sydney, Australia

Eighty one percent of a sample of long-term cannabis users was followed up at 1 year (162/200). Half (51%) were daily smokers, while 20% had substantially decreased or ceased use. More than half received a dependence diagnosis on each of three measures in the last year, with 44% dependent on all three. Remission was much more common than incidence of dependence. Nevertheless, use and dependence patterns were strongly related over time. Longitudinal analyses revealed that quantity of use and severity of dependence at baseline were the primary predictors of those same variables at follow-up. These data suggest that cannabis use and dependence are fairly stable among long-term users.

Cohort trends in youth suicide in Australia 1964-1997

OBJECTIVE

This paper examines trends in the rate of suicide among young Australians aged 15-24 years from 1964 to 1997 and presents an age-period-cohort analysis of these trends.

METHOD

Study design consisted of an age-period-cohort analysis of suicide mortality in Australian youth aged between 15 and 24 for the years 1964-1997 inclusive. Data sources were Australian Bureau of Statistics data on: numbers of deaths due to suicide by gender and age at death; and population at risk in each of eight birth cohorts (1940-1944, 1945-1949, 1950-1954, 1955-1959, 1960-1964, 1965-1969, 1970-1974, and 1975-1979). Main outcome measures were population rates of deaths among males and females in each birth cohort attributed to suicide in each year 1964-1997.

RESULTS

The rate of suicide deaths among Australian males aged 15-24 years increased from 8.7 per 100,000 in 1964 to 30.9 per 100,000 in 1997, with the rate among females changing little over the period, from 5.2 per 100,000 in 1964 to 7.1 per 100,000 in 1997. While the rate of deaths attributed to suicide increased over the birth cohorts, analyses revealed that these increases were largely due to period effects, with suicide twice as likely among those aged 15-24 years in 1985-1997 than between 1964 and 1969.

CONCLUSIONS

The rate of youth suicide in Australia has increased since 1964, particularly among males. This increase can largely be attributed to period effects rather than to a cohort effect and has been paralleled by an increased rate of youth suicides internationally and by an increase in other psychosocial problems including psychiatric illness, criminal offending and substance use disorders.

Isolation, cloning, and complete nucleotide sequence of a phenotypically distinct Brazilian isolate of human T-lymphotropic virus type II (HTLV-II)

Analysis of human T-lymphotropic virus type II (HTLV-II) isolates from North America and Europe have demonstrated the existence of two molecular subtypes of the virus, HTLV-IIa and HTLV-IIb. Recently, studies on HTLV-II infections in Brazil have revealed isolates that are related phylogenetically to the HTLV-IIa subtype but have a HTLV-IIb phenotype with respect to the transactivating protein, tax. To more clearly define this relationship, HTLV-II was isolated from peripheral blood of an IVDA from Sao Paulo, Brazil (SP-WV), and the complete provirus was cloned and sequenced. Comparison of HTLV-II(SP-WV) nucleotide sequences to other available complete HTLV-II proviral sequences revealed that HTLV-II(SP-WV) is most closely related to HTLV-II(Mo), the prototypic HTLV-IIa subtype sequence. Phylogenetic analysis of LTR, env, and tax regions unequivocally demonstrated that HTLV-II(SP-WV) and all other Brazilian sequences examined are members of the IIa subtype. The predicted amino acid sequences of the major coding regions of HTLV-II(SP-WV) are also most closely related to HTLV-II(Mo), with the important exception of tax. The tax protein encoded by HTLV-II(SP-WV) is 96-99% identical to the tax of IIb isolates and is similar in that it has an additional 25 amino acids at the carboxy-terminus compared to the HTLV-II(Mo) tax with which it shares 91% identity. Analysis of tax stop codon usage of a number of HTLV-IIa isolates from North American, Europe, and Brazil demonstrated that isolates from the last region appear to be unique in their extended tax phenotype. It could be demonstrated that the extended tax proteins in the HTLV-IIb and Brazilian isolates had equivalent ability to transactivate the viral LTR, and studies with deletion mutants indicated that the extended C-terminus is not essential for transactivation. In contrast, the HTLV-IIa tax was found to have a greatly diminished ability to transactivate the viral LTR, which appeared to be a consequence of reduced expression of the protein. The studies show that although the Brazilian strains do not represent an entirely new subtype based on nucleotide sequence analysis they are a phenotypically unique molecular variant within the HTLV-IIa subtype.

Microvascular anastomosis using 2-octyl cyanoacrylate in the rat femoral artery

Patency of the microvascular anastomosis is the most important requirement for tissue survival in free tissue transfer and in replantation. In efforts to improve on the standard suture method of microvascular anastomosis, new techniques such as limited-suture sleeve anastomoses and histoacryl glue anastomoses have been employed experimentally. However, as a result of factors such as tissue toxicity and suboptimal outcome, cyanoacrylates have not enjoyed clinical use. In addition, sleeve anastomoses continue to utilize suture, increasing the risks of intimal damage, platelet adhesion, and thrombosis. In an attempt to surmount these problems, the authors investigated the use of a new 2-octyl cyanoacrylate glue and a sutureless sleeve anastomosis. Anastomosis of 20 rat femoral arteries with a sutureless sleeve technique bonded with glue resulted in an 80% patency rate at 1 day to 3 weeks. Failures occurred in the first few attempts as the technique was evolving. These encouraging results suggest that 2-octyl cyanoacrylate may have applicability in quick, sutureless microvascular anastomoses.

Fluid phase endocytosis in oral epithelia: variation with site and effect of cancer

The structure of the oral mucosa has been extensively studied but its cell physiology has been less well characterised. This study aimed to show the range in variation in fluid phase endocytic capability in biopsies from different oral sites. Oral epithelial cells were obtained from both biopsies and single-cell suspensions obtained by brushing the oral cavity. Biopsies in organ culture and single cells in suspension were incubated with fluorescent microspheres of 0.02, 0.1 or 1.0 microm diameter. Endocytosis of fluorescent microspheres was quantitated by flow cytometry and visualised by confocal microscopy. Epithelial cells from all oral sites that were sampled internalised 0.02 microm and 0.1 microm but not 1.0 microm microspheres, with no significant differences observed between oral regions. Single cells from non-cancer patients endocytosed significantly more 0.02 microm microspheres than cells removed from patients with oral cancer. This model may be used to study integrated oral cell function both in health and disease.