Crystallization and preliminary X-ray diffraction studies of mammalian purple acid phosphatase

The oxidized form of purple acid phosphatase from pig allantoic fluid has been crystallized in the presence of phosphate using the hanging-drop technique. The crystals belong to the space group P2(1)2(1)2(1) and have unit-cell parameters a = 66.8, b = 70.3, c = 78.7 Angstrom. Diffraction data collected from a cryocooled crystal using a conventional X-ray source extend to 1.55 Angstrom resolution. A knowledge of the three-dimensional structure of mammalian purple acid phosphatase will aid in understanding the substrate specificity of the enzyme and will be important in the rational design of inhibitors, with potential in the treatment of bone diseases.

Emergence of multidrug-resistant tuberculosis in a community-based directly observed treatment programme in rural South Africa

OBJECTIVE: Although little studied in developing countries, multidrug-resistant tuberculosis (MDR-TB) is considered a major threat. We report the molecular epidemiology, clinical features and outcome of an emerging MDR-TB epidemic. METHODS: In 1996 all tuberculosis suspects in the rural Hlabisa district, South Africa, had sputum cultured, and drug susceptibility patterns of mycobacterial isolates were determined. Isolates with MDR-TB (resistant to both isoniazid and rifampicin) were DNA fingerprinted by restriction fragment length polymorphism (RFLP) using IS6110 and polymorphic guanine-cytosine-rich sequence-based (PGRS) probes. Patients with MDR-TB were traced to determine outcome. Data were compared with results from a survey of drug susceptibility done in 1994. RESULTS: The rate of MDR-TB among smear-positive patients increased six-fold from 0.36% (1/275) in 1994 to 2.3% (13/561) in 1996 (P = 0.04). A further eight smear-negative cases were identified in 1996 from culture, six of whom had not been diagnosed with tuberculosis. MDR disease was clinically suspected in only five of the 21 cases (24%). Prevalence of primary and acquired MDR-TB was 1.8% and 4.1%, respectively. Twelve MDR-TB cases (67%) were in five RFLP-defined clusters. Among 20 traced patients, 10 (50%) had died, five had active disease (25%) and five (25%) were apparently cured. CONCLUSIONS: The rate of MDR-TB has risen rapidly in Hlabisa, apparently due to both reactivation disease and recent transmission. Many patients were not diagnosed with tuberculosis and many were not suspected of drug-resistant disease, and outcome was poor.

Traditional healers as tuberculosis treatment supervisors: precedent and potential

SETTING: Hlabisa, South Africa. OBJECTIVE: To determine precedent and potential for traditional healers to act as tuberculosis (TB) treatment supervisors. METHODS: Literature review to describe precedent for the involvement of traditional healers in TB treatment supervision. Interviews with 100 TB patients to determine use of healers and their acceptability as supervisors. Interviews with 24 healers in the project sub-district to determine willingness to act as supervisors. RESULTS: Despite extensive literature on the interaction between traditional healers and conventional health services, including descriptions of traditional understandings of TB, no published work was identified that reported supervision of TB patients by traditional healers. Of 100 patients interviewed, only 10% had used a healer as the first health provider for their illness, but 40% had attended a healer at some time prior to diagnosis. Although only 4% believe healers can cure TB, 84% would consider choosing a healer as a treatment supervisor. Of the 24 healers, 15 (63%) distinguished between two types of diagnosis made among patients with. symptoms suggestive of TB: TB and idliso. Idliso is poisoning or bewitching, and is said to be best cured by healers, while TB is infectious and cannot be cured by healers. Most healers (88%) reported having referred patients with possible TB to hospital in the past; all were keen to negotiate collaboration with health services, and 92% were willing to act as treatment supervisors. CONCLUSIONS: While there is little reported precedent for traditional healers to interact formally with tuberculosis treatment services, the potential for collaboration seems to be high, at least in our setting.

Treatment of schizophrenia

This selective review on the treatment of schizophrenia provides an update on two important issues. Firstly, new antipsychotic drugs have improved the quality of life for people with schizophrenia. This review outlines some practical issues surrounding the use of these drugs. Secondly, evidence suggests that the prompt identification and treatment of people with psychoses (including schizophrenia and affective psychoses) results in improved clinical outcomes.1 The important role that general practitioners can play in reducing the duration of untreated psychosis is also discussed.

Weathering of hydrocarbons in mangrove sediments: testing the effects of using dispersants to treat oil spills

This field study was a combined chemical and biological investigation of the relative effects of using dispersants to treat oil spills impacting mangrove habitats. The aim of the chemistry was to determine whether dispersant affected the short- or long-term composition of a medium range crude oil (Gippsland) stranded in a tropical mangrove environment in Queensland, Australia. Sediment cores from three replicate plots of each treatment (oil only and oil plus dispersant) were analyzed for total hydrocarbons and for individual molecular markers (alkanes, aromatics, triterpanes, and steranes). Sediments were collected at 2 days, then 1, 7, 13 and 22 months post-spill. Over this time, oil in the six treated plots decreased exponentially from 36.6 +/- 16.5 to 1.2 +/- 0.8 mg/g dry wt. There was no statistical difference in initial oil concentrations, penetration of oil to depth, or in the rates of oil dissipation between oiled or dispersed oil plots. At 13 months, alkanes were >50% degraded, aromatics were similar to 30% degraded based upon ratios of labile to resistant markers. However, there was no change in the triterpane or sterane biomarker signatures of the retained oil. This is of general forensic interest for pollution events. The predominant removal processes were evaporation (less than or equal to 27%) and dissolution (greater than or equal to 56%), with a lag-phase of 1 month before the start of significant microbial degradation (less than or equal to 7%). The most resistant fraction of the oil that remained after 7 months (the higher molecular weight hydrocarbons) correlated with the initial total organic carbon content of the soil. Removal rate in the Queensland mangroves was significantly faster than that observed in the Caribbean and was related to tidal flushing. (C) 1999 Elsevier Science Ltd. All rights reserved.

Who fails to complete tuberculosis treatment? Temporal trends and risk factors for treatment interruption in a community-based directly observed therapy programme in a rural district of South Africa

SETTING: Hlabisa Tuberculosis Programme, Hlabisa, South Africa. OBJECTIVE: To determine trends in and risk factors for interruption of tuberculosis treatment. METHODS: Data were extracted from the control programme database starting in 1991. Temporal trends in treatment interruption are described; independent risk factors for treatment interruption were determined with a multiple logistic regression model, and Kaplan-Meier survival curves for treatment interruption were constructed for patients treated in 1994-1995. RESULTS: Overall 629 of 3610 surviving patients (17%) failed to complete treatment; this proportion increased from 11% (n = 79) in 1991/1992 to 22% (n = 201) in 1996. Independent risk factors for treatment interruption were diagnosis between 1994-1996 compared with 1991-1393 (odds ratio [OR] 1.9, 95% confidence interval [CT] 1.6-2.4); human immunodeficiency virus (HIV) positivity compared with HIV negativity (OR 1.8, 95% CI 1.4-2.4); supervised by village clinic compared with community health worker (OR 1.9, 95% CI 1.4-2.6); and male versus female sex (OR 1.3, 95% CI 1.1-1.6). Few patients interrupted treatment during the first 2 weeks, and the treatment interruption rate thereafter was constant at 1% per 14 days. CONCLUSIONS: Frequency of treatment interruption from this programme has increased recently. The strongest risk factor was year of diagnosis, perhaps reflecting the impact of an increased caseload on programme performance. Ensuring adherence to therapy in communities with a high level of migration remains a challenge even within community-based directly observed therapy programmes.

Diagnosis and treatment of mental disorders: a survey of Singapore mental health professionals

Background: A series of surveys of mental health literacy have been undertaken in Australia, involving members of the general public as well as general practitioners and mental health professionals, whereby respondents consider vignettes of depression and of schizophrenia, offer a diagnosis and rate a series of possible interventions for their judged helpfulness. A similar survey was undertaken in Singapore and is reported in this paper. Methods: The survey was undertaken at a large state psychiatric hospital with staff (psychiatrists, allied health professionals, psychiatrically and generally trained nursing staff) rating a vignette of mania, in addition to the vignettes derived in Australia for depression and schizophrenia, and with the Australian intervention options extended somewhat to respect Singapore facilities. Results: Responses of those in the four professional groups were compared. The psychiatrists were highly accurate in generating diagnoses, other staff somewhat less so for diagnosing depression (with a percentage instead choosing a diagnosis of stress) and mania (with a percentage instead diagnosing a schizophrenic condition). Reported helpfulness ratings identified those interventions judged consensually as likely to be helpful or harmful, as well as establishing some differences across the four professional groups. Conclusions: The consensus decisions of helpful treatments for depression and schizophrenia revealed very similar findings to judgements made by Australian professionals. The treated outcome of schizophrenia was judged as somewhat worse than that for mania and depression. While non-medical staff differed from psychiatrists in judging the comparative utility of some drug interventions and lifestyle issues, there was clear evidence of a relatively dominant 'medical model' to recommended treatments, while traditional healing practices and services were rated as distinctly unhelpful.

Knowledge discovery and data mining in biological databases

The new technologies for Knowledge Discovery from Databases (KDD) and data mining promise to bring new insights into a voluminous growing amount of biological data. KDD technology is complementary to laboratory experimentation and helps speed up biological research. This article contains an introduction to KDD, a review of data mining tools, and their biological applications. We discuss the domain concepts related to biological data and databases, as well as current KDD and data mining developments in biology.

The role of disulfide-linked dimerization in interleukin-3 receptor signaling and biological activity

Cysteine residues 86 and 91 of the beta subunit of the human interleukin (hIL)-3 receptor (h beta c) participate in disulfide-linked receptor subunit heterodimerization. This linkage is essential for receptor tyrosine phosphorylation, since the Cys-86 --> Ala (Mc4) and Cys-91 --> Ala (Mc5) mutations abolished both events. Here, we used these mutants to examine whether disulfide-linked receptor dimerization affects the biological and biochemical activities of the IL-3 receptor. Murine T cells expressing hIL-3R alpha and Mc4 or Mc5 did not proliferate in hIL-3, whereas cells expressing wild-type h beta c exhibited rapid proliferation. However, a small subpopulation of cells expressing each mutant could be selected for growth in IL-3, and these proliferated similarly to cells expressing wild-type h beta c, despite failing to undergo IL-3-stimulated h beta e tyrosine phosphorylation. The Mc4 and Mc5 mutations substantially reduced, but did not abrogate, IL-3-mediated anti-apoptotic activity in the unselected populations. Moreover, the mutations abolished IL-3-induced JAK2, STAT, and AKT activation in the unselected cells, whereas activation of these molecules in IL-3-selected cells was normal. In contrast, Mc4 and Mc5 showed a limited effect on activation of Erk1 and -2 in unselected cells. These data suggest that whereas disulfide-mediated cross-linking and h beta c tyrosine phosphorylation are normally important for receptor activation, alternative mechanisms can bypass these requirements.

Can tissue drug concentrations be monitored by microdialysis during or after isolated limb perfusion for melanoma treatment?

Isolated limb perfusion (ILP) with melphalan is used to treat recurrent melanoma. This study aimed to develop a microdialysis technique for melphalan tissue concentration measurement during ILP. The effects of melphalan concentration (50-600 mu g/ml), microdialysis flow rate (0.55-17.5 mu l/min), probe length (5-50 mm) and temperature (25-41.5 degrees C) on in vitro recovery were studied. In addition, in vivo recovery was measured in rat hindlimbs perfused with melphalan using 50 mm microdialysis probes implanted subcutaneously and into muscle. Both dialysate and tissue sample melphalan concentrations were determined by high performance liquid chromatography. The in vitro recovery of melphalan was not affected by melphalan concentration or temperature, but increased with probe length and decreased with flow rate. The melphalan concentrations in subcutaneous and muscle dialysates were not significantly different. A linear relationship was found between tissue dialysate concentrations and actual tissue concentrations of melphalan (r(2) = 0.97). Microdialysis is a potential method for tissue drug monitoring which may assist in the efficacious use of cytotoxics in human ILP. (C) 2000 Lippincott Williams & Wilkins.

Optimal release strategies for biological control agents: an application of stochastic dynamic programming to population management

1. Establishing biological control agents in the field is a major step in any classical biocontrol programme, yet there are few general guidelines to help the practitioner decide what factors might enhance the establishment of such agents. 2. A stochastic dynamic programming (SDP) approach, linked to a metapopulation model, was used to find optimal release strategies (number and size of releases), given constraints on time and the number of biocontrol agents available. By modelling within a decision-making framework we derived rules of thumb that will enable biocontrol workers to choose between management options, depending on the current state of the system. 3. When there are few well-established sites, making a few large releases is the optimal strategy. For other states of the system, the optimal strategy ranges from a few large releases, through a mixed strategy (a variety of release sizes), to many small releases, as the probability of establishment of smaller inocula increases. 4. Given that the probability of establishment is rarely a known entity, we also strongly recommend a mixed strategy in the early stages of a release programme, to accelerate learning and improve the chances of finding the optimal approach.

Alcohol- and drug-use disorders in Australia: implications of the National Survey of Mental Health and Wellbeing

Objective: This study reports the prevalence and correlates of ICD-10 alcohol- and drug-use disorders in the National Survey of Mental Health and Wellbeing (NSMHWB) and discusses their implications for treatment. Method: The NSMHWB was a nationally representative household survey of 10 641 Australian adults that assessed participants for symptoms of the most prevalent ICD-10 and DSM-IV mental disorders, including alcohol- and drug-use disorders. Results: In the past 12 months 6.5% of Australian adults met criteria for an ICD-10 alcohol-use disorder and 2.2% had another ICD-10 drug-use disorder. Men were at higher risk than women of developing alcohol- and drug-use disorders and the prevalence of both disorders decreased with increasing age. There were high rates of comorbidity between alcohol- and other drug-use disorders and mental disorders and low rates of treatment seeking. Conclusions: Alcohol-use disorders are a major mental health and public health issue in Australia. Drug-use disorders are less common than alcohol-use disorders, but still affect a substantial minority of Australian adults. Treatment seeking among persons with alcohol- and other drug-use disorders is low. A range of public health strategies (including improved specialist treatment services) are needed to reduce the prevalence of these disorders.

Effect of coinfection with STDs and of STD treatment on HIV shedding in genital-tract secretions - Systematic review and data synthesis

Objective: To determine whether coinfection with sexually transmitted diseases (STD) increases HIV shedding in genital-tract secretions, and whether STD treatment reduces this shedding. Design: Systematic review and data synthesis of cross-sectional and cohort studies meeting. predefined quality criteria. Main Outcome Measures: Proportion of patients with and without a STD who had detectable HIV in genital secretions, HIV toad in genital secretions, or change following STD treatment. Results: Of 48 identified studies, three cross-sectional and three cohort studies were included. HIV was detected significantly more frequently in participants infected with Neisseria gonorrhoeae (125 of 309 participants, 41%) than in those without N gonorrhoeae infection (311 of 988 participants, 32%; P = 0.004). HIV was not significantly more frequently detected in persons infected with Chlamydia trachomatis (28 of 67 participants, 42%) than in those without C trachomatis infection (375 of 1149 participants, 33%; P = 0.13). Median HIV load reported in only one study was greater in men with urethritis (12.4 x 10(4) versus 1.51 x 10(4) copies/ml; P = 0.04). In the only cohort study in which this could be fully assessed, treatment of women with any STD reduced the proportion of those with detectable HIV from 39% to 29% (P = 0.05), whereas this proportion remained stable among controls (15-17%), A second cohort study reported fully on HIV load; among men with urethritis, viral load fell from 12.4 to 4.12 x 10(4) copies/ml 2 weeks posttreatment, whereas viral load remained stable in those without urethritis. Conclusion: Few high-quality studies were found. HIV is detected moderately more frequently in genital secretions of men and women with a STD, and HIV load is substantially increased among men with urethritis, Successful STD treatment reduces both of these parameters, but not to control levels. More high-quality studies are needed to explore this important relationship further.

Neurons in the hilus region of the rat hippocampus are depleted in number by exposure to alcohol during early postnatal life

We have previously shown that exposing rats to a relatively high dose of ethanol during early postnatal life resulted in a deficit in spatial learning ability. This ability is controlled, at least in part, by the hippocampal formation. The purpose of the present study was to determine whether exposure of rats to ethanol during early postnatal life affected the number of specific neurons in the hippocampus. Wistar rats were exposed to a relatively high daily dose of ethanol between postnatal days 10 and 15 by placing them for 3 h each day in a chamber containing ethanol vapor. The blood ethanol concentration was about 430 mg/dl at the end of the exposure period. Groups of ethanol-treated (ET) rats, separation controls (SC), and mother-reared controls (MRC) were anesthetized and killed at 16 days of age by perfusion with phosphate-buffered glutaraldehyde (2.5%). The Cavalieri principle was used to determine the volume of various subdivisions of the hippocampal formation (CA1, CA2+CA3, hilus, and granule cell layer), and the physical disector method was used to estimate the numerical densities of neurons within each subdivision. The total number of neurons was calculated by multiplying estimates of the numerical density with the volume. There were, on average, about 441,000 granule cells in the granule cell layer and 153,000 to 177,000 pyramidal cells in both the CA1 and CA2+CA3 regions in all three treatment groups. In the hilus region, ET rats had about 27,000 neuronal cells. This was significantly fewer than the average of 38,000 such neurons estimated to be present in both MRC and SC animals. Thus, neurons in the hilus region may be particularly vulnerable to the effects of a high dose of ethanol exposure during early postnatal life. (C) 2000 Wiley-Liss, Inc.