Modeling the photoinactivation and transport of somatic and F-specific coliphages at a Great Lakes beach

Fecal indicator organisms (FIOs), such as Escherichia coli and enterococci, are often used as surrogates of contamination in the context of beach management; however, bacteriophages may be more reliable indicators than FIO due to their similarity to viral pathogens in terms of size and persistence in the environment. In the past, mechanistic modeling of environmental contamination has focused on FIOs, with virus and bacteriophage modeling efforts remaining limited. In this paper, we describe the development and application of a fate and transport model of somatic and F-specific coliphages for the Washington Park beach in Lake Michigan, which is affected by riverine outputs from the nearby Trail Creek. A three-dimensional model of coliphage transport and photoinactivation was tested and compared with a previously reported E. coli fate and transport model. The light-based inactivation of the phages was modeled using organism-specific action spectra. Results indicate that the coliphage models outperformed the E. coli model in terms of reliably predicting observed E. coli/coliphage concentrations at the beach. This is possibly due to the presence of additional E. coli sources that were not accounted for in the modeling. The coliphage models can be used to test hypotheses about potential sources and their behavior and for predictive modeling.

Biological Weighting Functions for Evaluating the Role of Sunlight-Induced Inactivation of Coliphages at Selected Beaches and Nearby Tributaries

Coliphages can indicate contamination of recreational waters and previous studies show that sunlight is important in altering densities of coliphages, other indicator microorganisms, and pathogens in aquatic environments. Here, we report on laboratory studies of light-induced inactivation of two coliphage groups-male-specific (F+) and somatic coliphage-under various conditions in phosphate-buffered water (PBW). Strains isolated from wastewater treatment facilities and laboratory strains (MS2 and phiX174 coliphages) were evaluated. Inactivation rates were determined in a series of irradiations using simulated solar radiation passed through light filters that blocked different parts of the ultraviolet spectral region. Inactivation rates and spectral irradiance from these experiments were then analyzed to develop biological weighting functions (BWFs) for the light-induced inactivation. BWFs were used to model the inactivation of coliphages over a range of conditions in aquatic environments that included two beach sites in Lake Michigan and one in Lake Erie. For example, modeled effects of sunlight attenuation, using UV absorption data from the three Great Lakes beach sites, inferred that direct photoinactivation rate constants, averaged over a one-meter water column in swimmable areas, were reduced 2- to 5-fold, compared to near-surface rate constants.

Using Integrated Environmental Modeling to Assess Sources of Microbial Contamination in Mixed-Use Watersheds

Microbial fate and transport in watersheds should include a microbial source apportionment analysis that estimates the importance of each source, relative to each other and in combination, by capturing their impacts spatially and temporally under various scenarios. A loosely configured software infrastructure was used in microbial source-to-receptor modeling by focusing on animal- and human-impacted mixed-use watersheds. Components include data collection software, a microbial source module that determines loading rates from different sources, a watershed model, an inverse model for calibrating flows and microbial densities, tabular and graphical viewers, software to convert output to different formats, and a model for calculating risk from pathogen exposure. The system automates, as much as possible, the manual process of accessing and retrieving data and completes input data files of the models. The workflow considers land-applied manure from domestic animals on undeveloped areas; direct shedding (excretion) on undeveloped lands by domestic animals and wildlife; pastureland, cropland, forest, and urban or engineered areas; sources that directly release to streams from leaking septic systems; and shedding by domestic animals directly to streams. The infrastructure also considers point sources from regulated discharges. An application is presented on a real-world watershed and helps answer questions such as: What are the major microbial sources? What practices contribute to contamination at the receptor location? What land-use types influence contamination at the receptor location? and Under what conditions do these sources manifest themselves? This research aims to improve our understanding of processes related to pathogen and indicator dynamics in mixed-use watershed systems.

Functional Evaluation of Three Manure-Borne Indicator Bacteria Release Models with Multiyear Field Experiment Data

Modeling the fate and transport of Escherichia coli is of substantial interest because of how this organism serves as an indicator of fecal contamination in microbial water quality assessment. The efficacy of models used to assess the export of E. coli from agricultural fields is dependent, in part, on submodels they utilize to simulate E. coli release from land-applied manure and animal waste. Although several release submodels have been proposed, they have only been evaluated and compared with data from laboratory or small plot E. coli release experiments. Our objective was to evaluate and compare performances of three manure-borne bacteria release submodels at field-scale: exponential release (EM), two-parametric Bradford and Schijven (B-S), and two-parametric Vadas-Kleinman-Sharpley (VKS); each was independently incorporated and tested as a submodel within the export model KINEROS2/STWIR, using E. coli. Dairy manure was uniformly applied via surface broadcasting once a year for six consecutive years on a 0.28 ha experimental field site. Two irrigation events followed each application: the first immediately followed the initial application and the second occurred one week later. Manure and soil samples were collected before and after irrigation, respectively, and manure, soil, and edge-of-field runoff samples were analyzed for E. coli. Model performance was evaluated with the Akaike criterion, coefficients of determination (R²), and root mean squared errors (RMSE) values. The percentage of exported manure-borne E. coli varied from 0.1% to 10% in most cases, generally reflecting the lag time between initiation of irrigation and initiation ofedge-of-field runoff. The export model performed better when using the VKS submodel which was preferred in 55% of cases. The B-S and EM submodels were preferred in 27% and 18% of cases, respectively. Two-parametric submodels were ultimately preferred over the single parameter submodel.

Capturing Microbial Sources Distributed in a Mixed-use Watershed within an Integrated Environmental Modeling Workflow

Many watershed models simulate overland and instream microbial fate and transport, but few provide loading rates on land surfaces and point sources to the waterbody network. This paper describes the underlying equations for microbial loading rates associated with 1) land-applied manure on undeveloped areas from domestic animals; 2) direct shedding (excretion) on undeveloped lands by domestic animals and wildlife; 3) urban or engineered areas; and 4) point sources that directly discharge to streams from septic systems and shedding by domestic animals. A microbial source module, which houses these formulations, is part of a workflow containing multiple models and databases that form a loosely configured modeling infrastructure which supports watershed-scale microbial source-to-receptor modeling by focusing on animal- and human-impacted catchments. A hypothetical application - accessing, retrieving, and using real-world data - demonstrates how the infrastructure can automate many of the manual steps associated with a standard watershed assessment, culminating in calibrated flow and microbial densities at the watershed's pour point.

Rainfall-induced release of microbes from manure: model development, parameter estimation, and uncertainty evaluation on small plots

A series of simulated rainfall-runoff experiments with applications of different manure types (cattle solid pats, poultry dry litter, swine slurry) was conducted across four seasons on a field containing 36 plots (0.75 × 2 m each), resulting in 144 rainfall-runoff events. Simulating time-varying release of Escherichia coli, enterococci, and fecal coliforms from manures applied at typical agronomic rates evaluated the efficacy of the Bradford-Schijven model modified by adding terms for release efficiency and transportation loss. Two complementary, parallel approaches were used to calibrate the model and estimate microbial release parameters. The first was a four-step sequential procedure using the inverse model PEST, which provides appropriate initial parameter values. The second utilized a PEST/bootstrap procedure to estimate average parameters across plots, manure age, and microbe, and to provide parameter distributions. The experiment determined that manure age, microbe, and season had no clear relationship to the release curve. Cattle solid pats released microbes at a different, slower rate than did poultry dry litter or swine slurry, which had very similar release patterns. These findings were consistent with other published results for both bench- and field-scale, suggesting the modified Bradford-Schijven model can be applied to microbial release from manure.

Survival of Manure-borne and Fecal Coliforms in Soil: Temperature Dependence as Affected by Site-Specific Factors

Understanding pathogenic and indicator bacteria survival in soils is essential for assessing the potential of microbial contamination of water and produce. The objective of this work was to evaluate the effects of soil properties, animal source, experimental conditions, and the application method on temperature dependencies of manure-borne generic , O157:H7, and fecal coliforms survival in soils. A literature search yielded 151 survival datasets from 70 publications. Either one-stage or two-stage kinetics was observed in the survival datasets. We used duration and rate of the logarithm of concentration change as parameters of the first stage in the two-stage kinetics data. The second stage of the two-stage kinetics and the one-stage kinetics were simulated with the model to find the dependence of the inactivation rate on temperature. Classification and regression trees and linear regressions were applied to parameterize the kinetics. Presence or absence of two-stage kinetics was controlled by temperature, soil texture, soil water content, and for fine-textured soils by setting experiments in the field or in the laboratory. The duration of the first stage was predominantly affected by soil water content and temperature. In the model dependencies of inactivation rates on temperature, parameter estimates were significantly affected by the laboratory versus field conditions and by the application method, whereas inactivation rates at 20°C were significantly affected by all survival and management factors. Results of this work can provide estimates of coliform survival parameters for models of microbial water quality.

Can E. coli or thermotolerant coliform concentrations predict pathogen presence or prevalence in irrigation waters?

An increase in food-borne illnesses in the United States has been associated with fresh produce consumption. Irrigation water presents recognized risks for microbial contamination of produce. Water quality criteria rely on indicator bacteria. The objective of this review was to collate and summarize experimental data on the relationships between pathogens and thermotolerant coliform (THT) and/or generic E. coli, specifically focusing on surface fresh waters used in or potentially suitable for irrigation agriculture. We analyzed peer-reviewed publications in which concentrations of E. coli or THT coliforms in surface fresh waters were measured along with concentrations of one or more of waterborne and food-borne pathogenic organisms. The proposed relationships were significant in 35% of all instances and not significant in 65% of instances. Coliform indicators alone cannot provide conclusive, non-site-specific and non-pathogen-specific information about the presence and/or concentrations of most important pathogens in surface waters suitable for irrigation. Standards of microbial water quality for irrigation can rely not only on concentrations of indicators and/or pathogens, but must include references to crop management. Critical information on microbial composition of actual irrigation waters to support criteria of microbiological quality of irrigation waters appears to be lacking and needs to be collected.

Comparing temperature effects on Escherichia coli, Salmonella, and Enterococcus survival in surface waters

The objective of this study was to compare dependency of survival rates on temperature for indicator organisms Escherichia coli and Enterococcus and the pathogen Salmonella in surface waters. A database of 86 survival datasets from peer-reviewed papers on inactivation of E. coli, Salmonella and Enterococcus in marine waters and of E. coli and Salmonella in lake waters was assembled. The Q10 model was used to express temperature effect on survival rates obtained from linear sections of semi-logarithmic survival graphs. Available data were insufficient to establish differences in survival rates and temperature dependencies for marine waters where values of Q10  = 3 and a survival rate of 0·7 day(-1) could be applied. The Q10 values in lake waters were substantially lower in marine waters, and Salmonella inactivation in lake water was, on average, twice as fast as E. coli; data on E. coli substantially outnumber data on Enterococcus and Salmonella. The relative increase in inactivation with increase in temperature is higher in marine waters than lake water, and differences in inactivation between Salmonella and E. coli at a given temperature were significant in lake water but not in marine waters.

SIGNIFICANCE AND IMPACT OF THE STUDY

Microbiological quality of surface waters is of paramount importance for public health. The novelty of this work is using a large compendium of published data to develop the first comparison of temperature effects on survival of the pathogen Salmonella and water quality indicator micro-organisms Escherichia coli and Enterococcus in natural waters. The existing relatively large body of knowledge on E. coli survival appears to be useful to assess the effect of temperature on survival of Salmonella. Moreover, results of this work constitute an essential input in models to support environmental management decisions on the use of surface water sources in agriculture, aquaculture and recreation.

Rainfall-induced fecal indicator organisms transport from manured fields: model sensitivity analysis

Microbial quality of surface waters attracts attention due to food- and waterborne disease outbreaks. Fecal indicator organisms (FIOs) are commonly used for the microbial pollution level evaluation. Models predicting the fate and transport of FIOs are required to design and evaluate best management practices that reduce the microbial pollution in ecosystems and water sources and thus help to predict the risk of food and waterborne diseases. In this study we performed a sensitivity analysis for the KINEROS/STWIR model developed to predict the FIOs transport out of manured fields to other fields and water bodies in order to identify input variables that control the transport uncertainty. The distributions of model input parameters were set to encompass values found from three-year experiments at the USDA-ARS OPE3 experimental site in Beltsville and publicly available information. Sobol' indices and complementary regression trees were used to perform the global sensitivity analysis of the model and to explore the interactions between model input parameters on the proportion of FIO removed from fields. Regression trees provided a useful visualization of the differences in sensitivity of the model output in different parts of the input variable domain. Environmental controls such as soil saturation, rainfall duration and rainfall intensity had the largest influence in the model behavior, whereas soil and manure properties ranked lower. The field length had only moderate effect on the model output sensitivity to the model inputs. Among the manure-related properties the parameter determining the shape of the FIO release kinetic curve had the largest influence on the removal of FIOs from the fields. That underscored the need to better characterize the FIO release kinetics. Since the most sensitive model inputs are available in soil and weather databases or can be obtained using soil water models, results indicate the opportunity of obtaining large-scale estimates of FIO transport from fields based on publicly available rather than site-specific information.

Using the Q10 model to simulate E. coli survival in cowpats on grazing lands

Microbiological quality of surface waters can be affected by microbial load in runoff from grazing lands. This effect, with other factors, depends on the survival of microorganisms in animal waste deposited on pastures. Since temperature is a leading environmental parameter affecting survival, it indirectly impacts water microbial quality. The Q10 model is widely used to predict the effect of temperature on rates of biological processes, including survival. Objectives of this work were to (i) evaluate the applicability of the Q10 model to Escherichia coli inactivation in bovine manure deposited on grazing land (i.e., cowpats) and (ii) identify explanatory variables for the previously reported E. coli survival dynamics in cowpats. Data utilized in this study include published results on E. coli concentrations in natural and repacked cowpats from research conducted the U.S. (Virginia and Maryland), New Zealand, and the United Kingdom. Inspection of the datasets led to conceptualizing E. coli survival (in cowpats) as a two-stage process, in which the initial stage was due to growth, inactivation or stationary state of the population and the second stage was the approximately first-order inactivation. Applying the Q10 model to these datasets showed a remarkable similarity in inactivation rates, using the thermal time. The reference inactivation rate constant of 0.042 (thermal days)(-1) at 20 °C gave a good approximation (R(2)=0.88) of all inactivation stage data with Q10=1.48. The reference inactivation rate constants in individual studies were no different from the one obtained by pooling all data (P<0.05). The rate of logarithm of the E. coli concentration change during the first stage depended on temperature. Duration of the first stage, prior to the first-order inactivation stage and the initial concentration of E. coli in cowpats, could not be predicted from available data. Diet and age are probable factors affecting these two parameters however, until their environmental and management predictors are known, microbial water quality modeling must treat them as a stochastic source of uncertainty in simulation results.

Escherichia coli survival in waters: temperature dependence

Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q₁₀ model. This suggestion was made 34 years ago based on 20 survival curves taken from published literature, but has not been revisited since then. The objective of this study was to re-evaluate the accuracy of the Q₁₀ equation, utilizing data accumulated since 1978. We assembled a database of 450 E. coli survival datasets from 70 peer-reviewed papers. We then focused on the 170 curves taken from experiments that were performed in the laboratory under dark conditions to exclude the effects of sunlight and other field factors that could cause additional variability in results. All datasets were tabulated dependencies "log concentration vs. time." There were three major patterns of inactivation: about half of the datasets had a section of fast log-linear inactivation followed by a section of slow log-linear inactivation; about a quarter of the datasets had a lag period followed by log-linear inactivation; and the remaining quarter were approximately linear throughout. First-order inactivation rate constants were calculated from the linear sections of all survival curves and the data grouped by water sources, including waters of agricultural origin, pristine water sources, groundwater and wells, lakes and reservoirs, rivers and streams, estuaries and seawater, and wastewater. Dependency of E. coli inactivation rates on temperature varied among the water sources. There was a significant difference in inactivation rate values at the reference temperature between rivers and agricultural waters, wastewaters and agricultural waters, rivers and lakes, and wastewater and lakes. At specific sites, the Q₁₀ equation was more accurate in rivers and coastal waters than in lakes making the value of the Q₁₀ coefficient appear to be site-specific. Results of this work indicate possible sources of uncertainty to be accounted for in watershed-scale microbial water quality modeling.

Bacterial infections of Chinook salmon, Oncorhynchus tshawytscha (Walbaum), returning to gamete collecting weirs in Michigan

Herein, we describe the prevalence of bacterial infections in Chinook salmon, Oncorhynchus tshawytscha (Walbaum), returning to spawn in two tributaries within the Lake Michigan watershed. Ten bacterial genera, including Renibacterium, Aeromonas, Carnobacterium, Serratia, Proteus, Pseudomonas, Hafnia, Salmonella, Shewanella and Morganella, were detected in the kidneys of Chinook salmon (n = 480) using culture, serological and molecular analyses. Among these, Aeromonas salmonicida was detected at a prevalence of ∼15%. Analyses revealed significant interactions between location/time of collection and gender for these infections, whereby overall infection prevalence increased greatly later in the spawning run and was significantly higher in females. Renibacterium salmoninarum was detected in fish kidneys at an overall prevalence of >25%. Logistic regression analyses revealed that R. salmoninarum prevalence differed significantly by location/time of collection and gender, with a higher likelihood of infection later in the spawning season and in females vs. males. Chi-square analyses quantifying non-independence of infection by multiple pathogens revealed a significant association between R. salmoninarum and motile aeromonad infections. Additionally, greater numbers of fish were found to be co-infected by multiple bacterial species than would be expected by chance alone. The findings of this study suggest a potential synergism between bacteria infecting spawning Chinook salmon.

High prevalence of buccal ulcerations in largemouth bass, Micropterus salmoides (Centrarchidae) from Michigan inland lakes associated with Myzobdella lugubris Leidy 1851 (Annelida: Hirudinea)

Widespread mouth ulcerations were observed in largemouth bass collected from eight inland lakes in the Lower Peninsula of Michigan during the summer months of 2002 and 2003. These ulcerations were associated with, and most likely caused by, leech parasitism. Through the use of morphological dichotomous keys, it was determined that all leeches collected are of one species: Myzobdella lugubris. Among the eight lakes examined, Lake Orion and Devils Lake had the highest prevalence of leech parasitism (34% and 29%, respectively) and mouth ulcerations (53% and 68%, respectively). Statistical analyses demonstrated that leech and ulcer prevalence varied significantly from one lake to the other. Additionally, it was determined that the relationship between the prevalence of ulcers and the prevalence of leech attachment is significant, indicating that leech parasitism is most likely the cause of ulceration. The ulcers exhibited deep hemorrhagic centers and raised irregular edges. Affected areas lost their epithelial lining and submucosa, with masses of bacteria colonizing the damaged tissues. Since largemouth bass is a popular global sportfish and critical to the food web of inland lakes, there are concerns that the presence of leeches, damaged buccal mucosa, and general unsightliness may negatively affect this important sportfishery.

Hepatitis B immunity in a population of drug and alcohol users

The objective of this study was to determine the level of immunity from Hepatitis B infection in an Australian population of drug and alcohol users, and the validity of self-reported immune status. A cross-sectional survey was employed of drug and alcohol users presenting for treatment, who were clients of De Paul House, a community-based drug and alcohol withdrawal service in Victoria. Outcome measures were: hepatitis B serology and personal reports of hepatitis B immunity. A total of 118 people were enrolled; 22% were injecting drug users and 48% reported past injecting drug use, while 55% were alcohol users; 51% had no general practitioner; 73% of participants were unaware of whether they were protected from hepatitis B infection, while 19.5% believed they were protected. However, serology demonstrated that 52.2% of those who believed they were protected were not immune. Only 21% of participants were immune. This is the first study in an Australian setting since the 1970s to examine the effectiveness of vaccination targeted to this population, and demonstrates low rates of immunity. New strategies are needed to deliver vaccination to this group. These will need to take account of the often chaotic nature of their lives, the poor validity of self-reported immunity, and the lack of primary care links.

Training program in the field of addiction medicine - an experience of learning while abroad

This paper illustrates the training program in the field of Addiction Medicine designed for primary care doctors by the Department of General Practice, School of Primary Care at Monash University in Melbourne. The nine month program was based around coursework, field visits and clinical observations. There were five modules that were completed and passed, twenty six Continuous Medical Education sessions attended, twenty nine field visits on Drug & Alcohol services, forty seven clinical visits and a total of three hundred and sixty clinical observations made. The comprehensive training program has benefited the first author in several ways to improve the Drugs & Alcohol services in Malaysia.

Isolation of viral haemorrhagic septicaemia virus from muskellunge, Esox masquinongy (Mitchill), in Lake St Clair, Michigan, USA reveals a new sublineage of the North American genotype

Viral haemorrhagic septicaemia virus (VHSV) was isolated from muskellunge, Esox masquinongy (Mitchill), caught from the NW portion of Lake St Clair, Michigan, USA in 2003. Affected fish exhibited congestion of internal organs; the inner wall of the swim bladder was thickened and contained numerous budding, fluid-filled vesicles. A virus was isolated using fish cell lines inoculated with a homogenate of kidney and spleen tissues from affected fish. Focal areas of cell rounding and granulation appeared as early as 24 h post-inoculation and expanded rapidly to destroy the entire cell sheet by 96 h. Electron microscopy revealed virions that were 170-180 nm in length by 60-70 nm in width having a bullet-shaped morphology typical of rhabdoviruses. The virus was confirmed as VHSV by reverse transcriptase-polymerase chain reaction. Sequence analysis of the entire nucleoprotein and glycoprotein genes revealed the virus was a member of the North American genotype of VHSV; however, the isolate was sufficiently distinct to be considered a separate sublineage, suggesting its origin may have been from marine species inhabiting the eastern coastal areas of the USA or Canada.

Substance misuse in first-episode psychosis: 15-month prospective follow-up study

BACKGROUND

Well-designed prospective studies of substance misuse in first-episode psychosis can improve our understanding of the risks associated with comorbid substance misuse and psychosis.

AIMS

To examine the potential effects of substance misuse on in-patient admission and remission and relapse of positive symptoms in first-episode psychosis.

METHOD

The study was a prospective 15-month follow-up investigation of 103 patients with first-episode psychosis recruited from three mental health services.

RESULTS

Substance misuse was independently associated with increased risk of in-patient admission, relapse of positive symptoms and shorter time to relapse of positive symptoms after controlling for potential confounding factors. Substance misuse was not associated with remission or time to remission of positive symptoms. Heavy substance misuse was associated with increased risk of in-patient admission, relapse and shorter time to relapse.

CONCLUSIONS

Substance misuse is an independent risk factor for a problematic recovery from first-episode psychosis.

Quantitative measure of muscle strength and size in chronic alcoholism: an early indication of tissue damage

We measured quadriceps strength and thickness in 101 male alcoholic patients and in 58 controls in order to investigate the force-size relationships of skeletal muscle in an alcoholic population. The relationship of these parameters with the duration of alcoholism, nutritional status and biochemical and haematological markers of heavy chronic alcohol use was investigated. Alcohol consumption of more than 42 standard drinks (420 g alcohol) per week for at least 5 years is associated with muscle weakness and wasting. There was no evidence of under-nutrition in these alcoholic subjects and muscle wasting occurred independently of peripheral neuropathy, a history of muscle pain, abnormalities of liver enzymes and elevation of mean red cell corpuscular volume. Quantitation of muscle size and strength in heavy drinkers may provide a useful early indicator of health impairment in alcoholics.

Assessment of methods of destruction of Syphacia muris eggs

An investigation was performed to identify methods suitable for decontamination of equipment being transferred from a facility contaminated with Syphacia muris to a new facility. Perianal samples were taken on clear sticky tape from rats known to be infected with S. muris. Tapes and attached worm eggs were treated with ethylene oxide, formaldehyde fumigation, potassium peroxysulphate, chlorine dioxide and didecyl di-methyl ammonium chloride, chlorine dioxide, alcohol/chlorhexidine, 100 degrees C dry heat for 30 min, ultraviolet light (UV), or left for 4 weeks at room temperature. The subsequent viability of the eggs was compared to untreated control samples. Heat and ethylene oxide produced a 100% kill rate of S. muris eggs. Formaldehyde gas and chlorine dioxide treatments showed marked effectiveness, with the number of eggs killed at 94% and 96%, respectively, while the other agents showed less efficacy (36-78% eggs killed). The percentage of eggs not hatching in the controls was 21%. Since so few agents were effective against S. muris eggs, care should be taken when choosing a method for decontaminating a facility.

LAAM maintenance vs methadone maintenance for heroin dependence

BACKGROUND

LAAM and methadone are both full mu opiate agonists and have been shown to reduce dependence on heroin when given continuously under supervised dosing conditions. LAAM has a long duration of action requiring dosing every two or three days compared to methadone which requires daily dosing. LAAM is not as widely available internationally as methadone, and may be withdrawn from the market following ten cases of life-threatening cardiac arrhythmias and an association with QT prolongation.

OBJECTIVES

To compare the efficacy and acceptability of LAAM maintenance with methadone maintenance in the treatment of heroin dependence.

SEARCH STRATEGY

We searched MEDLINE (January 1966 to August 2000), PsycINFO (1887 to August 2000), EMBASE (January 1985 to August 2000), and the Cochrane Controlled Trials Register (Issue 2 2000). In addition we hand searched NIDA monographs until August 2000 and searched reference lists of articles.

SELECTION CRITERIA

All randomised controlled trials, controlled clinical trials and controlled prospective studies comparing LAAM and methadone maintenance for the treatment of heroin dependence and measuring outcomes of efficacy or acceptability were included.

DATA COLLECTION AND ANALYSIS

Data on retention in treatment, heroin use, side-effects and mortality were collected by two reviewers independently. A meta-analysis was performed using RevMan. Discrepancies were resolved by consensus.

MAIN RESULTS

Eighteen studies, (15 RCTs, 3 Controlled prospective studies) met the inclusion criteria for the review. Three were excluded from the meta-analysis due to lack of data on retention, heroin use or mortality. Cessation of allocated medication (11 studies, 1473 participants) was greater with LAAM than with methadone, (RR 1.36, 95%CI 1.07-1.73, p=0.001, NNT=7.7 (or 8)). Non-abstinence was less with LAAM (5 studies, 983 participants; RR 0.81, 95%CI 0.72-0.91, p=0.0003, NNT=9.1 (or 10)). In 10 studies (1441 participants) there were 6 deaths from a range of causes, 5 in participants assigned to LAAM (RR 2.28 (95%CI 0.59-8.9, p=0.2). other relevant outcomes, such as quality of life and criminal activity could not be analysed because of lack of information in the primary studies.

REVIEWER'S CONCLUSIONS

LAAM appears more effective than methadone at reducing heroin use. More LAAM patients than methadone ceased their allocated medication during the studies, but many transferred to methadone and so the significance of this is unclear. There was no difference in safety observed, although there was not enough evidence to comment on uncommon adverse events.

Naltrexone for alcohol dependence: a randomized controlled trial

AIM

We examined the efficacy of naltrexone (an opioid antagonist) for alcohol dependence in a sample of alcohol-dependent men.

DESIGN

A 12-week randomized placebo-controlled clinical trial.

SETTING

The outpatient clinic of a combined war veteran and general teaching hospital in Melbourne, Australia.

PARTICIPANTS

Male alcohol-dependent subjects recruited from the community and from veteran groups.

INTERVENTION

Alcohol-dependent subjects were treated with 50 mg of naltrexone or placebo daily for 12 weeks. Both treatment groups attended a weekly education support group. Subjects were assessed weekly.

MEASUREMENTS

Primary study outcomes were the maintenance of abstinence and relapse to drinking.

FINDINGS

Fifty-five subjects were randomized to naltrexone and 56 to placebo. Forty subjects did not complete 12 weeks of therapy (17 naltrexone, 23 placebo). In the intention-to-treat sample (N = 111) fewer naltrexone treated subjects relapsed (p = 0.001). Among patients who completed the 12-week trial, naltrexone reduced the consumption of alcohol. Naltrexone was well tolerated and there were few adverse experiences.

CONCLUSIONS

These findings demonstrate that naltrexone is effective in preventing relapse to drinking in the setting of limited psychosocial treatment. Further studies should examine the duration of treatment needed to maintain the effect long term.

Naltrexone, a relapse prevention maintenance treatment of alcohol dependence: a meta-analysis of randomized controlled trials

The objective of this study was to review the evidence for the efficacy and toxicity of naltrexone, a treatment of alcohol dependence. A systematic review and meta-analysis of randomized controlled trials of naltrexone used in the treatment of alcohol dependence was conducted. We searched MEDLINE, EMBASE, PsychLIT and the Cochrane Controlled Trials Registry for articles published between 1976 to January 2001. The manufacturer of naltrexone was asked to submit additional complete trial reports not in the literature. We analysed data from seven studies that compared naltrexone to placebo. The meta-analysis of benefit indicates that naltrexone is superior to placebo. Subjects treated with naltrexone experience significantly fewer episodes of relapse, and significantly more remain abstinent when compared to placebo-treated subjects [risk difference of relapse rates = -14% [95% confidence interval (CI): -23%, -5%]; and risk difference of abstinence rates = 10% (95% CI: 4%, 16%)] after 12 weeks of treatment. The naltrexone-treated subjects also consume significantly less alcohol over the study period than do placebo-treated subjects. There is no significant difference between naltrexone and placebo in terms of the number of subjects with at least one adverse event or the number of subjects who discontinued the trial due to an adverse event.

Prevalence of psychiatric disorder in a methadone maintenance population

OBJECTIVE

The objective of this study was to examine the prevalence of psychiatric disorders in a group of patients who had recently entered a methadone maintenance programme.

METHOD

A total of 62 patients were interviewed using the Composite International Diagnostic Interview (CIDI) within 6 months of commencing methadone maintenance. The CIDI was used to establish symptoms of psychiatric illness at interview and in the 12 months prior.

RESULTS

In the 12 months prior to interview, 76% of the sample fulfilled ICD-10 criteria for a psychiatric disorder other than substance-use disorder. Over half of the group interviewed fulfilled ICD-10 criteria for an affective disorder, two-thirds fulfilled criteria for an anxiety disorder and just under half fulfilled diagnostic criteria for both an affective disorder and an anxiety disorder in the 12 months prior to interview. At the time of interview, 19% fulfilled ICD-10 diagnostic criteria for a moderate or severe affective disorder. Seventy per cent of males and 89% of females interviewed had a comorbid psychiatric illness. In 71% of the group who had a comorbid psychiatric illness, the onset of psychiatric symptomatology was reported to predate the use of heroin.

CONCLUSION

The prevalence of psychiatric disorder is up to 10 times higher in the population on methadone maintenance than in the general population and is two to three times higher than that found in community surveys of those with a substance-use disorder. These results are consistent with earlier findings and have implications for service planning.

Factorial invariance for combined Wechsler Adult Intelligence Scale-Revised and Wechsler Memory Scale-Revised scores in a sample of clients with alcohol dependency

This study examined the joint factor structure of the WAIS-R and WMS-R in a sample of 289 participants (mostly males) with alcohol dependency. In a confirmatory phase we contrasted a range of factor models derived from previous analyses of the Wechsler scales. The best fitting model incorporated five factors representing Verbal Comprehension, Perceptual Organization, Attention-Concentration, Verbal Memory, and Visual Memory, with reassignment of factor loadings for two subtests. The invariance of the measurement model was then examined comparing data from a large sample of healthy participants (J. R. Carstairs & E. A. Shores, 1999). The results indicated that the number of factors was invariant across samples, and four of the factors satisfied the criterion of partial measurement invariance.

Working memory impairments in alcohol-dependent participants without clinical amnesia

BACKGROUND

The delayed alternation (DA) task is highly sensitive to the deficits of nonhuman animals with alcohol-related brain damage. DA is thought to measure working memory which serves as a temporary store for processing of information. However, performance on this type of task has only been investigated in alcohol-dependent humans with severe cognitive deficits. The aim of the current study was to explore the validity of DA as a test sensitive to alcohol-related brain damage by manipulating storage and processing components in three versions of the task. It was hypothesized that alcohol-dependent people would perform worse than control participants and that their deficits would be more pronounced in DA versions with maximal working memory demands.

METHODS

A sample of 12 alcohol-dependent participants without Wernicke-Korsakoff syndrome was compared with a sample of 12 nonalcohol-dependent controls on three versions of DA. These versions, in order of increasing working memory demand, were single alternation (LR), double alternation (LLRR), and asymmetric alternation (LRRR). DA was administered on a personal computer and performance measured by the number of trials taken to reach criterion.

RESULTS

Alcohol-dependent participants, compared with the control participants, took more trials to reach learning criterion on DA on all versions when analyzed together (p = 0.002). Performance on DA was also found to deteriorate with increased working memory demands in both groups of participants (p < 0.001). However, the deficits of alcohol-dependent participants were most pronounced on the DA task with moderate (LLRR) as opposed to extreme (LRRR) working memory demands.

CONCLUSIONS

The results indicate that both storage and processing demands are necessary for task performance and demonstrate sensitivity of DA to alcohol-related brain injury.

Thiamin treatment and working memory function of alcohol-dependent people: preliminary findings

BACKGROUND

Wernicke-Korsakoff syndrome (WKS) is most often seen in people who are alcohol dependent. Treatment with thiamin may rapidly resolve acute symptoms. However, much evidence suggests that identification of WKS on clinical examination is relatively insensitive when compared with diagnosis at postmortem. No study has investigated the therapeutic effect of thiamin in a sample of alcohol-dependent people without the clinical triad of acute WKS.

METHODS

We conducted a randomized, double-blind, multidose study of thiamin treatment in 107 subjects who were detoxifying from alcohol. Five groups of subjects were assessed with the Mini-Mental State Examination and were examined for the presence of neurological signs. Subjects were given different doses of intramuscular thiamin for two consecutive days. The posttreatment performance of these groups then was examined on a test of working memory derived from comparative neuropsychology, namely, the delayed alternation task. This test has been established as sensitive to the neuropathology of WKS.

RESULTS

Pretreatment measures of mental status and neurological signs were equivalent across groups. Groups were equated with respect to the background variables of age, education, typical daily alcohol consumption, and years of drinking. On the posttreatment measure, a superior performance was found in the group that received the highest dose of thiamin, compared with the other four treatment groups.

CONCLUSIONS

A therapeutic relationship between dose and working memory performance was indicated. These results have important implications for the management and prevention of WKS, but further investigations are needed to substantiate the nature of the therapeutic relationship.

Anaesthesia of the common marmoset (Callithrix jacchus) using continuous intravenous infusion of alphaxalone/alphadalone

A safe means of anaesthetizing common marmosets (Callithrix jacchus) for a study using magnetic resonance imaging (MRI) to investigate cerebral ischaemia was required. Continuous infusion of alphaxalone/alphadalone was used to anaesthetize 37 marmosets for non-recovery and recovery experiments. This was found to give safe, reliable anaesthesia when coupled with pulse oximetry and electrocardiographic (ECG) monitoring.

Confirmatory factor analysis of the Wechsler Memory Scale-Revised in a sample of clients with alcohol dependency

Previous analyses of the Wechsler Memory Scale-Revised (WMS-R; Wechsler, 1987) have reported one-, two-, and three-factor solutions and raised questions about the validity of the visual memory subtests. These various findings may stem in part from different methods of analysis, and from the study of different participant samples. To address these issues, we analysed data from the WMS-R and a spatial maze test administered to 154 participants with a history of alcohol dependence. Results from confirmatory factor analysis supported the interpretation of three factors underlying the WMS-R subtests and the spatial maze score in this sample, namely, attention-concentration, immediate memory, and delayed recall. This result held despite the inclusion of the maze score which is a well-validated measure of visuo-spatial memory.

Comparison of alcohol consumption patterns and social problems between women and men drink-drivers

OBJECTIVE

To compare the sociodemographic characteristics, patterns of alcohol consumption and driving histories of women and men drink-drivers.

DESIGN

Cross-sectional descriptive study.

SETTING AND SUBJECTS

All 156 women who attended the Drink-Drive Program at St Vincent's Hospital, Melbourne, between January 1990 and December 1993, and an age-matched sample of 298 men attending in the same period. All had been disqualified from driving after a conviction for driving under the influence of alcohol.

OUTCOME MEASURES

Self-reported weekly alcohol consumption and expenditure on alcohol at apprehension and during the program; blood alcohol level (BAL) at apprehension; demographic characteristics; number of previous drink-drive and other traffic convictions; and score on the Michigan Alcoholism Screening Test (MAST).

RESULTS

Women had a higher educational level than men, and were more likely to be managers or professionals and to live in areas of high socioeconomic status. Women reported lower levels of weekly alcohol consumption at both apprehension (women: 15.2 standard drinks; men: 31.6 standard drinks) and during the program (women: 7.1 standard drinks; men: 12.0 standard drinks) but had similar BALs to men at apprehension (mean, 0.12% [26 mmol/L]). Sixty percent of women drank wine, or wine, beer and spirits, while 75% of men drank beer. Women had lower MAST scores than men (mean [standard deviation]: women, 5.8 [5.2]; men, 8.9 [8.2]). Women were less likely than men to have prior convictions for drink-driving or other traffic offences.

CONCLUSION

Although women presented with similar blood alcohol levels to men, their drinking patterns and sociodemographic characteristics differ greatly. Health education for women drink-drivers needs to have a different strategy to that for men.

Multimedia benchmarking analysis for three risk assessment models: RESRAD, MMSOILS, and MEPAS

This paper is one in a series that describes results of a benchmarking analysis initiated by the Department of Energy (DOE) and the United States Environmental Protection Agency (EPA). An overview of the study is provided in a companion paper by Laniak et al. presented in this journal issue. The three models used in the study--RESRAD (DOE), MMSOILS (EPA), and MEPAS (DOE)--represent analytically-based tools that are used by the respective agencies for performing human exposure and health risk assessments. Both single media and multimedia benchmarking scenarios were developed and executed. In this paper, the multimedia scenario is examined. That scenario consists of a hypothetical landfill that initially contained uranium-238 and methylene chloride. The multimedia models predict the fate of these contaminants, plus the progeny of uranium-238, through the unsaturated zone, saturated zone, surface water, and atmosphere. Carcinogenic risks are calculated from exposure to the contaminants via multiple pathways. Results of the tests show that differences in model endpoint estimates arise from both differences in the models' mathematical formulations and assumptions related to the implementation of the scenarios.

An overview of a multimedia benchmarking analysis for three risk assessment models: RESRAD, MMSOILS, and MEPAS

Multimedia modelers from the United States Environmental Protection Agency (EPA) and the United States Department of Energy (DOE) collaborated to conduct a detailed and quantitative benchmarking analysis of three multimedia models. The three models--RESRAD (DOE), MMSOILS (EPA), and MEPAS (DOE)--represent analytically-based tools that are used by the respective agencies for performing human exposure and health risk assessments. The study is performed by individuals who participate directly in the ongoing design, development, and application of the models. Model form and function are compared by applying the models to a series of hypothetical problems, first isolating individual modules (e.g., atmospheric, surface water, groundwater) and then simulating multimedia-based risk resulting from contaminant release from a single source to multiple environmental media. Study results show that the models differ with respect to environmental processes included (i.e., model features) and the mathematical formulation and assumptions related to the implementation of solutions. Depending on the application, numerical estimates resulting from the models may vary over several orders-of-magnitude. On the other hand, two or more differences may offset each other such that model predictions are virtually equal. The conclusion from these results is that multimedia models are complex due to the integration of the many components of a risk assessment and this complexity must be fully appreciated during each step of the modeling process (i.e., model selection, problem conceptualization, model application, and interpretation of results).

Induction of anaesthesia with halothane and isoflurane in the rabbit: a comparison of the use of a face-mask or an anaesthetic chamber

The effects of induction of anaesthesia with halothane or isoflurane were studied in rabbits. The anaesthetic agents were delivered either via a face-mask, or the animals were placed in an anaesthetic induction chamber. All rabbits had periods of apnoea during induction, lasting 30-120 s, resulting in moderate hypercapnia and acidosis. Periods of apnoea were associated with a marked bradycardia. The combination of bradycardia and hypercapnia during induction may represent an increased risk of anaesthetic associated mortality. Animals in all groups tried to avoid inhaling anaesthetic vapour, and this behaviour, together with the occurrence of breath-holding suggests that induction was aversive.

Alcohol-related health problems in the elderly

Alcohol misuse is common in the elderly, and the problem may be compounded by the body's reduced ability to metabolise ethanol and interactions with over-the-counter and prescription drugs. Older heavy drinkers are likely to present with mental health problems--anxiety, depression, dementia, confusion and sleep disturbance--or physical problems--gait disturbance, falls and liver disease. Alcohol use must be accurately assessed, and physical, neurological and mental state examinations performed. Treatment should be individualised, with the patient's needs being matched to the treatment options available.

Anaesthesia of laboratory rabbits using etorphine/methotrimeprazine and midazolam

The use of etorphine (a potent mu-opioid), methotrimeprazine (a phenothiazine tranquilizer) and midazolam (a benzodiazepine) in laboratory rabbits is described. The central ear artery was cannulated under local anaesthesia using lignocaine/prilocaine cream, enabling cardiovascular monitoring in conscious animals. Anaesthesia was characterized by respiratory arrest, profound analgesia and a stable cardiovascular system (after commencing intermittent positive pressure ventilation). Reversal of anaesthesia with buprenorphine (a partial mu agonist) did not reduce the degree of post-operative respiratory depression, but shortened the period of unconsciousness considerably. This anesthetic regimen can only be recommended for rabbits that are free of respiratory disease and if facilities for IPPV are available.

The use of etorphine/methotrimeprazine and midazolam as an anaesthetic technique in laboratory rats and mice

The results of a preliminary evaluation of etorphine/methotrimeprazine ('Small Animal Immobilon') and midazolam in rats and mice are reported, and this regimen is compared to fentanyl/fluanisone/midazolam in mice. In rats, a surgical plane of anaesthesia with good muscle relaxation was produced, but blood gas analysis showed the presence of severe hypoxia, hypercapnia and acidosis. In mice etorphine/methotrimeprazine/midazolam and fentanyl/fluanisone/midazolam produced adequate anaesthesia, but blood gas analysis showed severe respiratory depression with both regimens. Since etorphine/methotrimeprazine/midazolam produced severe respiratory depression in rats and mice it is suggested that this regimen is used with caution. Administration of supplemental oxygen would seem advisable when using either etorphine/methotrimeprazine/midazolam or fentanyl/fluanisone/midazolam in rats and mice.

The assessment of depth of anaesthesia in animals and man

The assessment of the depth of anaesthesia in man has received much attention in recent years, following a number of reports of people being aware during surgery. A range of different measures have been suggested for determining the adequacy of anaesthesia in man, but such a critical assessment is rarely applied to laboratory animals. This article describes the methods used to assess anaesthetic depth in both man and animals, and compares the relative states of knowledge about anaesthetic depth in animals and man.

Oesophageal propulsive force and its relation to manometric pressure

A fixed volume capsule incorporating a force transducer and a side hole for manometric measurements was constructed and calibrated. Simultaneous measurements of the propulsive (aboral) force and the manometric pressure (intraluminal pressure) were made at 5, 10, and 15 cm above the lower oesophageal sphincter and in response to dry and wet (5, 10, and 15 ml) swallows. The propulsive force and manometric pressure waves had a simultaneous onset and were of similar duration. Peak values of propulsive force for wet swallows increased significantly as measurements were made progressively more distally within the oesophagus and were greatest in the distal oesophagus. The association between manometric pressure and propulsive force is not strong (r = 0.61) suggesting that intraluminal pressure is a poor predictor of propulsive force and hence an unreliable measure of oesophageal 'function'.

Biological markers of alcoholism

The roles of two categories of biological markers--those relating to alcohol consumption and those relating to the risk of developing alcohol related problems--are reviewed. Platelet Mono-amino oxidase levels are low in individuals with a strong inheritance of their drinking problem (Cloninger Type II alcoholics). Elevated gamma-glutamyl transpeptidase (GGT) levels identify regular heavy drinkers with a sensitivity between 40-60%. Mean corpuscular volume (MCV) has a high specificity (95%) and is useful in detecting regular heavy drinkers in the ambulatory care population if other causes of an elevated MCV can be included.

Does a blood alcohol level of 0.15 or more identify accurately problem drinkers in a drink-driver population?

OBJECTIVE

To determine whether a blood alcohol concentration (BAC) of 0.15 or more identifies accurately problem drinking in an apprehended drinking driver.

DESIGN

Cross-sectional analytic study of 86 drink drivers ("diagnostic test study").

SETTING

St Vincent's Hospital, Melbourne, drink-driver education programme.

SUBJECTS

Men aged between 18-25 years, applying for relicensing after disqualification, who were participants at 10 consecutive drink-driver education courses conducted in early 1987.

OUTCOME MEASURES

Self-reports of the amount of alcohol consumed and the amount of money spent on alcohol per week, the standard Michigan Alcoholism Screening Test (MAST) score and the blood alcohol level at apprehension. The first three measures were used as reference standards for alcohol-related problems, against which the blood alcohol level was compared.

MAJOR RESULTS

Scatter plots of BAC against amount consumed, amount spent and the MAST scores showed that a large proportion of the heaviest drinkers were not identified by the BAC. Log-transformed correlation coefficients were: for amount spent v. amount consumed, r = 0.73; for MAST score v. amount consumed, r = 0.52, and for MAST score v. amount spent r = 0.53. Correlating the BAC with the log of the MAST score gave r = 0.21, BAC with log of the amount consumed, r = 0.20, and BAC with log of the amount spent, r = 0.15. Comparing a BAC of 0.15 or more with a MAST score of greater than or equal to 5, we obtained a sensitivity of 0.36, a specificity of 0.76, a positive predictive value of 0.86, and a negative predictive value of 0.23. The prevalence of heavy drinking as measured by the MAST score was 0.80.

CONCLUSION

A blood alcohol concentration of 0.15 or more identifies only a third of the problem drinkers in this sample of drink drivers. Although it selected a group of drinkers with alcohol-related problems, it missed most of the problem drinkers and did not reliably identify the heaviest drinkers.