Occupational health : hearing of October 12, 1976, Los Angeles /

"no. 566."

Chlorination for degrading saxitoxins (paralytic shellfish poisons) in water

Chlorination was investigated as a treatment option for degrading and thus removing saxitoxins (paralytic shellfish poisons, PSPs) produced by cyanobacteria (blue-green algae) from water. It was found to be effective with the order of ease of degradation of the saxitoxins being GTX5 (B1) similar to dcSTX > STX > GTX3 similar to C2 > C1 > GTX2. However the effectiveness of chlorine was pH dependent. Degradation as a function of pH was not linear with the degree of degradation increasing rapidly at around pH 7.5. At pH 9 > 90% removal was possible provided a residual of 0.5 mg l(-1) free chlorine was present after 30 min contact time. The more effective degradation at higher pH was unexpected as chlorine is known to be a weaker oxidant under these conditions. The more effective degradation, then, must be due to the toxins, which are ionisable molecules, being present in a form at higher pH which is more susceptible to oxidation. The feasibility of using chlorine to remove saxitoxins during water treatment will therefore depend strongly on the pH of the water being chlorinated. Degradation may be improved by pH adjustment but may not be a practical solution. Although saxitoxins were degraded in that the parent compounds were not detected by chemical analysis, there is no indication as to the nature of the degradation products. However, acute toxicity as determined by the mouse bioassay was eliminated.

A comparison of the efficacy and safety of olanzapine versus haloperidol during transition from intramuscular to oral therapy

Background: Acutely agitated patients with schizophrenia who receive intramuscular (IM) medications typically are switched to oral (PO) antipsychotic maintenance therapy Objective: The goal of this study was to assess the efficacy and safety of olanzapine versus those of haloperidol during transition from IM to PO therapy We used additional data from a previously reported trial to test the hypothesis that the reduction in agitation achieved by IM olanzapine 10 mg or IM haloperidol 7.5 mg would be maintained following transition to 4 days of PO olanzapine or PO haloperidol (5-20 mg/d for both). We also hypothesized that olanzapine would maintain its more favorable extrapyramidal symptom (EPS) safety profile. Methods: This was a multinational (hospitals in 13 countries), double-blind, randomized, controlled trial. Acutely agitated inpatients with schizophrenia were treated with 1 to 3 IM injections of olanzapine 10 mg or haloperidol 7.5 mg over 24 hours and were entered into a 4-day PO treatment period with the same medication (5-20 mg/d for both). The primary efficacy measurement was reduction in agitation, as measured by the Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) score. Adverse events and scores on EPS rating scales were assessed. Results: A total of 311 patients (204 men, 107 women; mean [SD] age, 38.2 [11.6] years) were enrolled (131, 126, and 54 patients in the olanzapine, haloperidol, and placebo groups, respectively). In all, 93.1% (122/131) of olanzapine-treated patients and 92.1% (116/126) of haloperidol-treated patients completed the IM period and entered the PO period; 85.5% (112/131) of olanzapine-treated patients and 84.1% (106/126) of haloperidol-treated patients completed the PO period. IM olanzapine and IM haloperidol effectively reduced agitation over 24 hours (mean [SD] PANSS-EC change, -7.1 [4.8] vs -6.7 [4.3], respectively). Reductions in agitation were sustained throughout the PO period with both study drugs (mean [SD] change from PO period baseline, -0.6 [4.8] vs -1.3 [4.4], respectively). During PO treatment, haloperidol-treated patients spontaneously reported significantly more acute dystonia than olanzapine-treated patients (4.3% [5/116] vs 0% [0/122], respectively; P = 0.026) and akathisia (5.2% [6/116] vs 0% [0/122], respectively; P = 0.013). Significantly more haloperidol-treated patients than olanzapine-treated patients met categorical criteria for treatment-emergent akathisia (18.5% [17/92] vs 6.5% [7/107], respectively; P = 0.015). Conclusions: In the acutely agitated patients with schizophrenia in this study, both IM olanzapine 10 mg and IM haloperidol 7.5 mg effectively reduced agitation over 24 hours. This alleviation of agitation was sustained following transition from IM therapy to 4 days of PO treatment (5-20 mg/d for both). During the 4 days of PO treatment, olanzapine-treated patients did not spontaneously report any incidences of acute dystonia, and olanzapine had a superior EPS safety profile to that of haloperidol. The combination of IM and PO olanzapine may help improve the treatment of acutely agitated patients with schizophrenia. Copyright (C) 2003 Excerpta Medica, Inc.

Effectiveness and safety of repeat courses of hylan G-F 20 in patients with knee osteoarthritis

Objective: To compare the effectiveness and safety of repeat treatment with hylan G-F 20 based on data from a randomized, controlled trial [Raynauld JP, Torrance GW, Band PA, Goldsmith CH, Tugwell P, Walker V, et al. A prospective, randomized, pragmatic, health outcomes trial evaluating the incorporation of hylan G-F 20 into the treatment paradigm for patients with knee osteoarthritis (Part 1 of 2): clinical results. Osteoarthritis Cartilage 2002;10:506-17]. The hypotheses tested were whether the single-course and repeat-course subgroups would be superior to appropriate care and not different from each other. Method: A total of 255 patients with knee osteoarthritis were randomized to appropriate care with hylan G-F 20 or appropriate care without hylan G-F 20. The hylan G-F 20 group was partitioned into two subgroups: (1) patients who received a single course of hylan G-F 20; and (2) patients who received two or more courses of hylan G-F 20. Results: For the primary effectiveness measure, change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score as a percent of baseline, the single-course subgroup improved by 41%, the repeat-course subgroup by 35%, and the appropriate care group by 14%. Both subgroups improved significantly more than the appropriate care group (P < 0.05), and were not statistically significantly different from each other (70% power to detect a 20% difference). Secondary effectiveness measures showed similar results. In the repeat-course subgroup, no statistically significant differences were found in the number of local adverse events, the number of patients with local adverse events, or arthrocentesis rates between the first and repeat courses of treatment. Conclusions: Although the study was neither designed nor powered to examine repeat treatment, this a posteriori analysis provides support for a favorable effectiveness and safety profile of hylan G-F 20 in repeat course patients. (C) 2004 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Assessment of two arsenic-contaminated drinking water mitigation interventions in Bangladesh

Arsenic is a carcinogen. In Bangladesh, there are over 10 million tube-wells of which about 50% have arsenic concentrations exceeding the WHO recommended guideline value of 10 μg/L for drinking water. This study aimed to evaluate the efficacy of two relatively inexpensive mitigation interventions, three-pitcher filters and dug-wells. A randomised controlled field trial was conducted in Natore. Six Hundred and forty participants, 60 clusters of 47 villages were included in the trial. Two hundred and six participants were selected for the control group, 218 participants for the dug-wells, and 216 participants for the three-pitcher filters. The average arsenic in the drinking water was 128 μg/L in the three-pitcher trial. Twelve months post intervention, about 30% of the filtered water samples were >50 μg/L whereas dug-well water was

Interaction of psychosocial risk factors explain increased neck problems among female office workers

This study investigated the relationship between psychosocial risk factors and (1) neck symptoms and (2) neck pain and disability as measured by the neck disability index (NDI). Female office workers employed in local private and public organizations were invited to participate, with 333 completing a questionnaire. Data were collected on various risk factors including age, negative affectivity, history of previous neck trauma, physical work environment, and task demands. Sixty-one percent of the sample reported neck symptoms lasting greater than 8 days in the last 12 months. The mean NDI of the sample was 15.5 out of 100, indicating mild neck pain and disability. In a hierarchical multivariate logistic regression, low supervisor support was the only psychosocial risk factor identified with the presence of neck symptoms. Similarly, low supervisor support was the only factor associated with the score on the NDI. These associations remained after adjustment for potential confounders of age, negative affectivity, and physical risk factors. The interaction of job demands, decision authority, and supervisor support was significantly associated with the NDI in the final model and this association increased when those with previous trauma were excluded. Interestingly, and somewhat contrary to initial expectations, as job demands increased, high decision authority had an increasing effect on the NDI when supervisor support was low. Crown copyright (c) 2006 Published by Elsevier B.V. All rights reserved.