Chondrogenic and adipogenic potential of microvascular pericytes.

BACKGROUND: Previous studies have shown that pericytes can differentiate into osteoblasts and form bone. This study investigated whether pericytes can also differentiate into chondrocytes and adipocytes. METHODS AND RESULTS: Reverse transcription-polymerase chain reaction demonstrated that pericytes express mRNA for the chondrocyte markers Sox9, aggrecan, and type II collagen. Furthermore, when cultured at high density in the presence of a defined chondrogenic medium, pericytes formed well-defined pellets comprising cells embedded in an extracellular matrix rich in sulfated proteoglycans and type II collagen. In contrast, when endothelial cells were cultured under the same conditions, the pellets disintegrated after 48 hours. In the presence of adipogenic medium, pericytes but not endothelial cells expressed mRNA for peroxisome proliferator-activated receptor-gamma2 (an adipocyte-specific transcription factor) and incorporated lipid droplets that stained with oil red O. To confirm that pericytes can differentiate along the chondrocytic and adipocytic lineages in vivo, these cells were inoculated into diffusion chambers and implanted into athymic mice for 56 days. Accordingly, mineralized cartilage, fibrocartilage, and a nonmineralized cartilaginous matrix with lacunae containing chondrocytes were observed within these chambers. Small clusters of cells that morphologically resembled adipocytes were also identified. CONCLUSIONS: These data demonstrate that pericytes are multipotent cells that may contribute to growth, wound healing, repair, and/or the development and progression of various pathological states.

Testing of saliva for antibodies to HIV-1.

To determine whether saliva is a potentially useful sample for screening for HIV infection when serum is not obtainable, saliva and serum samples from 50 HIV-infected and 50 uninfected subjects were tested for antibody to HIV-1 (anti-HIV-1) using a second-generation enzyme-linked immunosorbent assay (ELISA; Abbott) and prototype antibody-capture ELISA (Wellcome). Of saliva specimens from HIV-infected people, six gave negative results on the Abbott and one on the Wellcome assays; all specimens from uninfected people were negative by both assays. Sensitivity for the Abbott assay was therefore 88.0% [95% confidence interval (Cl) 76.2-94.4%], an unacceptable level for screening purposes. Sensitivity for the Wellcome assay was 98% (95% Cl 89.5-99.6%), a more satisfactory level for population screening. Further validation of this technique is necessary, and of methods for collection of saliva specimens in particular.

Declining risk for HIV among injecting drug users in Kathmandu, Nepal: the impact of a harm-reduction programme.

OBJECTIVE: To measure changes in self-reported risk behaviour for HIV infections and HIV seroprevalence among injecting drug user (IDU) clients of an outreach harm-reduction programme in Kathmandu, Nepal. METHODS: The Lifesaving and Lifegiving Society (LALS) of Kathmandu began providing sterile injecting equipment and education to Nepalese IDU in 1991. A sample of these IDU were interviewed and tested for HIV each year from 1991 through 1994. RESULTS: Indicators of unsafe injecting fell, as knowledge of HIV rose more in 1994 for those who had been in touch with LALS for longer. Indicators of unsafe sex did not change. HIV seroprevalence remained low, 1.6% in 1991 and 0% in 1994. CONCLUSION: We conclude that programmes for the prevention of HIV spread among IDU are possible and effective in Asia, and are urgently needed.

PIP: To reduce the high rate of human immunodeficiency virus (HIV) infection among intravenous drug users in Nepal, the Lifesaving and Lifegiving Society of Kathmandu has been distributing sterile injecting equipment in exchange for contaminated materials since 1991. In addition, community health outreach workers affiliated with the program provide condoms and bleach, HIV counseling and education, and primary health care to about 750 of the estimated 1500-2000 intravenous drug users in the Kathmandu valley. Of the 48,386 client contacts in 1991-94, over half involved syringe exchange. During this period, 586 randomly selected clients were selected for interviews and serologic testing. The number of times drug users shared equipment declined from 14 times per week in the 1991 subsample to once a day or less in the 1993 and 1994 subsamples. Knowledge of HIV infection rose from 58% in 1991 to almost 100% in 1994, while the proportion of drug users considering themselves at risk of HIV increased from 25% to 47%. There were no significant changes in HIV seropositivity (1.6% in 1991) during the study period, and no new cases were recorded in 1993 or 1994. This finding confirms the effectiveness of needle/syringe exchange programs in controlling the spread of HIV infection among intravenous drug users.

AIDS in Malaysia.

PIP: The first people to be infected with HIV in Malaysia were mainly homosexual men with foreign connections. IV drug users, however, rapidly became the population group with the highest prevalence of HIV. Accurate, timely data are needed in order to responsibly describe the pattern of HIV infection and AIDS in any given setting. In Malaysia, however, there has been little systematic surveillance in population groups other than blood donors. This surveillance indicates the existence of a rapidly increasing rate of seropositivity among blood donors. Otherwise, many people are loathe to undergo voluntary HIV testing to determine their serostatus. Moreover, some people with STDs avoid contact with the health system and the potential for HIV testing. The extent to which AIDS cases are underreported or reported late is unknown. On the other hand, an estimated 10% of notified AIDS cases have been wrongly classified as such. The lack of hard data on HIV/AIDS in Malaysia makes it difficult to project the future course of the epidemic in the country. Since Malaysia shares a land border with Thailand and there is much sea-borne traffic between the two countries, it is highly possible that Malaysia will experience a significant epidemic of HIV infection similar to its neighbors. A National AIDS Committee was established April 1985 to develop responses to the HIV epidemic, while the National AIDS Program Manager of the Ministry of Health is responsible for controlling STDs. A national plan of action for the prevention and control of AIDS, drawn up in 1985 and revised in 1988, includes planning for the continued surveillance of HIV infection and AIDS through existing notification systems, and for screening and sentinel programs for IV drug users, prostitutes, and STD patients. Recent nongovernmental organization responses complement government efforts to prevent HIV and AIDS in Malaysia.^ieng

The pattern of diagnosed HIV infection in Australia, 1984-1992.

OBJECTIVE: To describe the pattern of newly diagnosed HIV infection in Australia, between 1984 and 1992. METHODS: State and Territory health authorities reported cases of newly diagnosed HIV infection to the national HIV surveillance centre. Information sought on each case included the State or Territory of diagnosis, the case identifying number, the sex, date of birth and postcode of residence of the person with newly diagnosed HIV infection, the source of exposure to HIV and the date of specimen collection for the diagnosis of infection. RESULTS: By the end of December 1992, a total of 16,765 cases of newly diagnosed HIV infection had been reported in Australia. The annual number of cases declined between 1985 and 1992. Most diagnoses were among males, and exposure to HIV was attributed to male homosexual contact for more than 80% of cases for which information on exposure to HIV was available. Cases of HIV infection attributed to heterosexual contact represented an increasing proportion of the annual number of diagnoses over the period 1985-1992, among both men and women. CONCLUSION: National surveillance for newly diagnosed HIV infection has complemented national surveillance for diagnoses of AIDS as a key mechanism for monitoring the course of the HIV epidemic in Australia. The pattern of newly diagnosed HIV infection was similar to the pattern of AIDS diagnoses, with the overwhelming majority of diagnoses of infection being in adult males whose exposure to HIV was attributed to homosexual contact. Limitations of HIV surveillance include the lack of information on HIV testing patterns, incomplete information on HIV exposure histories and duplication of reported diagnoses.

Evaluation of enzyme-linked immunosorbent assays: a method of data analysis.

Diagnostic tests are usually evaluated in terms of simple qualitative measures of sensitivity and specificity. When comparing different quantitative assays such as ELISAs, it is often more useful to deal with actual values (sample optical density/cut-off optical density ratio (OD ratio] rather than the qualitative relationship to the cut-off, i.e. positive or negative. This allows for a statistical approach to the questions of sensitivity and specificity. The National HIV Reference Laboratory of Australia has developed an approach for determining statistical estimates of sensitivity and specificity in terms of delta (delta). Delta is defined as the distance of the mean OD ratio of the sample population from the cut-off measured in standard deviation units. This paper discusses the derivation of this measurement and its usefulness when evaluating ELISA tests.

An evaluation of competitive and second generation ELISA screening tests for antibody to HIV.

Two competitive anti-HIV ELISA screening assays (Behring and Wellcozyme) and two second generation assays using antigens generated by recombinant DNA technology (Abbott) and synthetic peptides (Biochrom) were evaluated against common panels of anti-HIV positive sera and sera known or thought likely to give false positive reactions. The assays were also tested on fresh sequential blood donations. Conventional estimates of sensitivity and specificity did not reveal a significant difference between the assays. Statistical analyses using log10 transformed data to determine delta values (the distance of the mean optical density (OD) ratio from the cut-off measured in standard deviation units) showed the Abbott assays to have the highest probability (greater than 99.99%) of detecting anti-HIV positive samples and the Behring assay as having the highest probability (greater than 99.99%) of correctly identifying anti-HIV negative specimens. The combined data from conventional estimates of sensitivity and specificity and delta values suggests that the Abbott assay is the test of choice for screening purposes.

Tuberculosis infection and homelessness in Melbourne, Australia, 1995-1996.

OBJECTIVE: To describe tuberculosis infection among persons experiencing homelessness in inner Melbourne, Australia. DESIGN: Homeless people were surveyed during late 1995 and early 1996. In stage one of the study 284 homeless people from crisis and long-term accommodation sites were recruited by means of stratified, systematic, random sampling. In stage two a convenience sample of 100 homeless people from squats and the streets were recruited. Participants completed a questionnaire and Mantoux testing was performed. RESULTS: A past history of tuberculosis was reported by 3%. Thirty-seven per cent had a Mantoux > or =10 mm; 21% > or =15 mm; and 11% > or =20 mm. A Mantoux > or =15 mm was independently associated with being aged > or =40 years, coming from the accommodated sample, overseas birth, and a past history of tuberculosis. Using logistic regression modelling, a Mantoux > or =15 mm was predicted by being aged > or =40 years, overseas birth, and past history of tuberculosis. CONCLUSION: Mantoux test results suggest that this group of homeless people had a high prevalence of infection with the tubercle bacillus. Many aspects of the physical and social circumstances of homeless people predispose to reactivation and have the potential to enhance rapid spread should latent infection become active disease.

The effects of methadone on immune function among injecting drug users: a review.

Methadone maintenance therapy is advocated as a major preventive strategy for the spread of the human immunodeficiency virus (HIV) and other blood-borne infectious agents among injecting drug users (IDUs) because of its effects in decreasing the frequency of injecting and presumably sharing of equipment. As an opioid agonist, methadone may share the direct and indirect immunoregulatory effects of other opioids, and thus affect susceptibility to, and the natural history of, HIV infection. Available evidence pertaining to methadone and immune function is reviewed. The long-term immunosuppression observed in heroin injectors on present (incomplete) evidence appears to be caused by factors associated with a drug-using lifestyle rather than by a direct action of heroin. Although data are conflicting, it is most likely that methadone does not significantly impair immune function and is safe for HIV-infected IDUs, possibly even allowing some improvement of immune function to occur. The increasing reliance placed on methadone maintenance to control the epidemic of HIV infection in IDUs requires that remaining uncertainties regarding methadone and immune function are clarified urgently.

The first hit: circumstances surrounding initiation into injecting.

Initiation into injecting is a crucial event for continued reproduction of an injecting drug using (IDU) population and for exposure to blood-borne viruses, but little is known about how this happens. Three hundred young injectors were interviewed in Melbourne by peer workers within the first few years of beginning to inject, about the circumstances surrounding their initiation. Most had indications of social disruption, including having left school early, unemployment, family disruption, homelessness and incarceration. First drug injected was most often amphetamines (average age 16 years), most having already used amphetamines by a different route of administration, but with a steady movement thereafter to heroin as the drug of choice. The most common scenario was one in which injecting was unplanned but the person was active in bringing about the initiation. Most identified a significant other who initiated them (few of whom were dealers), and over half had subsequently initiated others into injecting, on average 0.6 per year; after 5 years 237 young injectors had initiated at least 420 others. Those who initiated multiple others were more likely to be unemployed, to inject multiple drugs and to have dealt. Modelling injecting as a communicable phenomenon, where appropriate, may help estimate population dynamics among IDUs. Peer education programmes are likely to be the most effective harm reduction approach among new injectors.

Methadone maintenance and hepatitis C virus infection among injecting drug users.

Harm reduction strategies for the prevention of transmission of human immunodeficiency virus (HIV) transmission among injecting drug users (IDUs) have been widely implemented in Australia and are seen to have been effective in preventing the spread of HIV. A major strategy has been increasing the availability of and accessibility to methadone maintenance therapy (MMT) programmes. We have reviewed the experience of a major MMT general practice with hepatitis C virus (HCV) infection from 1991 to 1995. Of 1741 individuals tested for HCV antibodies at least once 66.7% were positive. Of 73 IDUs who were initially seronegative and were retested at least once, 19 were subsequently seropositive. Seroconverters to HCV were younger than non-seroconverters, and were more likely to have evidence of previous hepatitis B infection. The overall HCV incidence rate was 22 cases per 100 person-years, and this did not differ between those on MMT programs (continuous or interrupted) between HCV tests and those not on MMT. These findings suggest that the role of MMT in the control of the spread of HCV infection among IDUs needs further assessment, and that control of the current epidemic of HCV infection among IDUs in Australia will be very difficult.

Epidemiology of hepatitis C virus infection among injecting drug users in Australia.

STUDY OBJECTIVE: To review the epidemiology of hepatitis C virus (HCV) infection among injecting drug users (IDUs) in Australia, and consider needs for further research and prevention policies and programmes. DESIGN: (1) Review of the results of surveillance for HCV; (2) review of published literature on prevalence, incidence, and risk factors for HCV among IDUs; and (3) reconstruction of incidence rates from prevalence studies of HCV in IDUs. SETTING AND PARTICIPANTS: Field and clinic based studies of IDUs in Australia. MAIN RESULTS: HCV has been present at high prevalences (of the order of 60-70%) in populations of Australian IDUs since at least 1971. Duration of injecting and main drug injected were the main predictors of seropositivity, the latter possibly a surrogate for frequency of injecting and both together as surrogate for cumulative numbers of times injected. Risk of infection begins with first injection and continues as long as injecting does. Current incidence is approximately 15 per 100 person years, and up to 40 per 100 person years in some subpopulations. Incidence may have decreased through the 1980s as a result of behaviour change in relation to HIV, as it has for hepatitis B, but not significantly so. CONCLUSIONS: Control of HCV infection in Australia will depend on effectiveness of measures to control HCV spread among IDUs. This will be a greater challenge than the control of HIV in this population has been. Needs identified include improved surveillance, especially for recently acquired infection, better understanding of exact transmission modes, and urgent improvement in prevention strategies.

A possible outbreak of listeriosis caused by an unusual strain of Listeria monocytogenes.

During 1987, a cluster of 23 cases of listeriosis due to an unusual serotype of Listeria monocytogenes was identified. All the 'epidemic' strains (designated serovar 4b(X)) were indistinguishable by serotyping, phage-typing and monoclonal antibody-typing. Clusters of cases due to this type have not been identified previously in Britain at such a high frequency. In an epidemiological survey, patients were interviewed so as to identify risk factors but none common in all cases was identified.

Late presentation of HIV infection associated with prolonged survival following AIDS diagnosis--characteristics of individuals.

Individuals who present late with human immunodeficiency virus (HIV) infection do not benefit from advances in drug therapies that delay their progression to acquired immunodeficiency syndrome (AIDS). This paper describes these individuals and their subsequent survival and investigates predictors of late presentation. All AIDS diagnoses from 1992-1998 notified to the Victorian State AIDS Registry were included. Subjects were grouped as individuals diagnosed with AIDS within 8 weeks of a first positive HIV test (late presenters), or individuals for whom there was more than 8 weeks between AIDS diagnosis and first positive HIV test (non-late presenters). Of 1021 AIDS diagnoses notified, 24% were late presenters. Late presentation was associated with increasing age, being bisexual or heterosexual, being born in Asia, southern Europe or South America and being diagnosed at a hospital. Late presenters survived longer following AIDS diagnosis (P < 0.0001). This increased survival may indicate a positive response by drug naïve patients to antiretroviral therapies following AIDS diagnosis.

Hepatitis infection among adolescents resident in Melbourne Juvenile Justice Centre: risk factors and challenges.

OBJECTIVE: To describe patterns of infection with, and risks for, hepatitis A, B and C viruses (HAV, HBV, and HCV) in male adolescents detained in the Melbourne Juvenile Justice Centre (MJJC). METHODS: A cross-sectional serosurvey for HAV, HBV, and HCV among 90 male adolescents aged 15-18 years who were resident in MJJC for more than 1 week in 1996. RESULTS: Nine percent had been exposed to HAV, 8% were positive or equivocal for exposure to HBV, and 21% were antibody positive for HCV. All those with hepatitis markers except one positive for HAV had been injection heroin users for more than 1 year. Of those who were not HBcAb positive, only 28% were immune to HBV. For most respondents, sexual and drug-using risks began in the early teens and were associated with leaving school prematurely. CONCLUSIONS: Respondents were vulnerable to exposure to blood-borne viruses from an early age, posing a challenge for health education programs. An opportunity exists for harm minimization and prevention of spread of blood-borne viruses within the first year of injection drug use in this population.

Hitting up in the top end: characteristics of needle exchange clients in Darwin.

OBJECTIVE: Little is known about injecting drug use (IDU) and blood-borne viral (BBV) infection in rural Australia. METHOD: These repeat cross-sectional studies were conducted during a two-week period in July and October-November 1998 at the Darwin needle exchange, with 129 and 121 respondents respectively. RESULTS: The commonest drug of choice was heroin, but the commonest drug injected was morphine. Self-reported sharing of needles and syringes was uncommon. Self-reported serostatus for HIV was high (8% and 11.4% respectively), but seemingly mostly associated with sexual rather than IDU risk; for hepatitis C (HCV) status, these were 54% and 37%. Among IDUs of Aboriginal or Torres Strait Islander (ATSI) background, who made up 14% of the first round respondents, patterns of IDU and of BBV infection were the same as among non-ATSI respondents. CONCLUSIONS: These surveys reveal patterns of IDU in Darwin that have both similarities and differences with those in the major urban centres in Australia. In the absence of a comprehensive methadone maintenance program, many participate in a more or less informal morphine substitution program. HIV is present among these IDUs, and the risks of further sexual transmission may be high. IMPLICATIONS: These surveys confirm the presence among injecting drug users in Darwin of HIV, HBV and HCV, and of the risk for further spread of these viruses. Control of blood-borne virus transmission among IDUs requires an even greater commitment to abolishing sharing of needles and syringes, and therefore continued support and enhancement of needle and syringe availability.

Health care costs of a continuing epidemic of hepatitis C virus infection among injecting drug users.

OBJECTIVES: To estimate the direct health care costs of a continuing epidemic of hepatitis C virus (HCV) infection among injecting drug users (IDUs) in Australia from the formal health care system's perspective. DESIGN: A Markov cohort model is used to map the disease paths of successive hypothetical cohorts of 1,000 patients as they develop the sequelae of HCV over an extended period of time. PATIENTS AND SETTING: IDUs becoming infected with HCV. OUTCOME MEASURES: Estimates of the number of persons in each of a limited number of disease states are used in conjunction with direct medical costs associated with ambulatory visits and inpatient hospital admissions over the course of the disease to estimate the long-term impact on the health care system of HCV infection among successive cohorts of IDUs. RESULTS: For every 1,000 IDUs newly infected with hepatitis C in a given year, there is an implied $14.32 million in health care spending over the years as sequelae become manifest, with cumulative total costs of some $0.5 billion (1994 dollars) after 60 years as the costs of successive cohorts of HCV-infected IDUs are added to the prevalence pool. If the estimated 10,000 new HCV infections in IDUs in Australia per year continue for the next 60 years, total direct health care costs will be around $4 billion over that period. CONCLUSIONS: Efforts to prevent HIV transmission among IDUs have been shown to be clearly cost-effective. These data imply that there is an even more pressing need to halt or slow the current epidemic of HCV infection among IDUs on fiscal grounds alone.

Tracing and recruiting a cohort with community acquired hepatitis 25 years later.

OBJECTIVE: We describe the methods used to trace and recruit a cohort (including injecting drug users) 25 years after admission to hospital in Melbourne with hepatitis. METHODS: Information recorded in the original medical record was used for tracing purposes. Subjects were located using the electoral roll, CD-ROM telephone directory, the Health Insurance Commission database, Hepatitis Foundation newsletters, advertising and features in the press and local radio. Other approaches included contacting local medical officer or next of kin from the original admission, and the National Death Registry. RESULTS: Tracing was undertaken on all members of the cohort; two-thirds were located. Methods were applied sequentially and 36% were found by CD-ROM telephone directory and the electoral roll, 33% from Health Insurance records, 15% by letter to last known address, 10% from contact of original next of kin, 3% from radio publicity and 1% from media advertisements. Of those who were located, 85% participated in the study. CONCLUSIONS: Accurate ascertainment of birth date and full name from original case records was essential for tracing purposes. Use of Health Insurance records and CD-ROM telephone directory and the electoral roll were the most successful means of locating subjects while newspaper advertising was non-productive and expensive. History of IDU was the major association with failure to trace and unwillingness to enrol, but despite this tracing and recruitment was high in this group. The high participation rate in those located appears to be due to the experience of the staff member making the initial contact.

A profile of HIV testing in Victoria to the end of 1993. Victorian Collaborative Group on HIV and AIDS Surveillance (VCGHAS).

Examination of testing patterns for human immunodeficiency virus (HIV) in a population is important because it affects interpretation of surveillance data on new HIV diagnoses and can guide the targeting and evaluation of campaigns to encourage appropriate antibody testing. This report describes a relatively inexpensive mechanism of collecting information on who is being tested for HIV in Victoria (other than at the Blood Bank). The annual number of HIV tests performed in Victoria increased steadily throughout the 1980s but the rate of increase slowed in the early 1990s. By 1993, women accounted for almost half of HIV tests, although they made up only 8 per cent of positive tests. There were marked differences in the volume of testing and testing profiles of different laboratories. The information available on personal risk category and the reasons for HIV tests show that many people of low risk are tested, although conclusions are limited by inadequate information elicited or provided by many requesting doctors. For better information on what is occurring with respect to HIV testing, the fundamental requirement is better compliance from requesting doctors in supplying basic information on who they test and why.

Vietnamese-speaking injecting drug users in Melbourne: the need for harm reduction programs.

While research on aspects of injecting drug use (IDU), including injecting and sexual risks for HIV transmission, has been progressing in 'mainstream' Australian populations, there has been little among non-English speaking background (NESB) communities in Australia, particularly the South-East Asian communities, of which the Vietnamese is the largest. This exploratory study employed and trained peer workers to recruit and interview IDUs of Vietnamese origin in Melbourne on a wide range of subjects related to risks associated with their drug using, as an initial assessment of risk-taking behaviours for blood-borne viruses among Vietnamese-speaking IDUs. A finger-prick blood sample was taken where possible to measure antibody status to HIV, HBV and HCV. The profile which emerged was not dissimilar to that of their English-speaking counterparts prior to the benefit of currently available harm-reduction programs. A relatively isolated group whose social world often related only to other Vietnamese-speaking drug users, they were engaging in unsafe sex and unsafe injecting and were unfamiliar with procedures for cleaning injecting equipment and where they could seek out information and services, including needle exchanges. This study has identified an urgent need not only to promote currently available information and services to this group, but also to provide culturally relevant education and other harm-reduction measures needed to prevent transmission of HIV, other BBVs and STDs. The study has highlighted the lack of responsiveness of mainstream health services to the needs of Vietnamese-speaking IDUs.