bluuebunny/crossref_metadata_2025_split huggingface dataset:
High mortality among young crack cocaine users in Brazil: a 5‐year follow‐up study
Authors: Ribeiro Marcelo , Dunn John , Laranjeira Ronaldo , Sesso Ricardo 
Published: August 2004

ABSTRACTAims  Follow‐up studies show that smokers, alcoholics and heroin addicts have high mortality rates, but there is little information on crack users. We have investigated the mortality rate among this population, including its risk factors and causes of death.Design  A 5‐year follow‐up study.Participants and setting  A cohort of 131 crack‐dependent patients, admitted to a public detoxification unit in São Paulo between 1992 and 1994.Measurements  Data collected from a structured personal interview and from a review of patients’ hospital records, confirming the deaths from records held at the Municipal Offices.Findings  Of the 124 (94.6%) patients located, 23 (18.5%) had died (a mortality ratio of 7.6). Homicide was the most common cause of death (n = 13). Observed mortality rate, adjusted for age and sex, was 24.92 per 1000, while the expected all‐cause mortality rate in São Paulo, also adjusted for age and sex, was 3.28 per 1000, giving an excess mortality rate of 21.64 per 1000. Survival analysis showed that the probability of being alive 5 years post‐treatment was 0.80 (95% CI = 0.77–0.84). Cox's proportional hazards regression showed three factors predicted mortality: history of intravenous drug use (hazard ratio 3.28, 95% CI 1.42–7.59), unemployment at index admission (hazard ratio 3.48, 95% CI 1.03–11.80) and premature discharge from index admission (hazard ratio 2.21, CI 0.94–5.18).Conclusions  Community‐based and tailored interventions should be considered to improve those patients’ social support and permanence in treatment.
Changing profiles of injecting drug users with AIDS in a Hispanic population
Authors: Amill Alejandro , Gómez María De Los A. , Fernández Diana M. , Bangdiwala Shrikant I. , Ríos Eddy , Hunter Robert F. 
Published: August 2004

ABSTRACTAims  To describe and assess the changing trends in socio‐demographic, risk, clinical and immunological parameters in male intravenous drug users (IDU) with AIDS.Design, setting and participants  Baseline description by year of entry of 610 male IDU with AIDS who entered into a cohort study in Bayamón, Puerto Rico, from 1992 to 2000. Study participants were evaluated at in‐patient health‐care facilities in the University Hospital Ramón Ruiz Arnau or in the ambulatory immunology clinic facilities.Findings  The median age at which subjects entered the study and the proportion of patients with an educational level lower than a high school degree increased from 1992 to 2000. Upward trends were also observed in the practice of injecting non‐prescription drugs during the last 12‐month period, the practice of needle sharing and the use of a combination of heroin and cocaine (‘speedballs’). Higher proportions of subjects were also diagnosed with wasting syndrome and bacterial pneumonia. The median CD4 count recorded at entry decreased over the course of the study.Conclusions  Puerto Rican male IDU diagnosed with AIDS are arriving at health‐care facilities in the latest stages of the disease. Better and early interventions with different health care approaches need to be developed.
Efficacy of bupropion and predictors of successful outcome in a sample of French smokers: a randomized placebo‐controlled trial
Authors: Aubin H. J. , Lebargy F. , Berlin I. , Bidaut‐Mazel C. , Chemali‐Hudry J. , Lagrue G. 
Published: August 2004

ABSTRACTBackground  Previous published studies assessed the efficacy of bupropion in smoking cessation only in North American populations of smokers. Results of therapeutic drug trials are not always directly applicable in other populations.Aims  To confirm the efficacy of bupropion in smoking cessation in European smokers.Design  A multi‐centre, randomized, double‐blind placebo‐controlled trial.Setting  Seventy‐four smoking cessation out‐patient clinics in France.Participants  The study included 509 smokers motivated to quit smoking.Intervention  Subjects were randomized to either slow‐release bupropion 150 mg b.i.d. (B) or to placebo (Pl) in a 2 : 1 ratio, treated for 7 weeks, and followed‐up for 26 weeks.Measurements  Main outcome measure: 6 months’ point prevalence abstinence, determined by self‐report and expired air carbon monoxide measurement. Secondary outcome measures: weeks 4–7 and weeks 4–26 continuous abstinence rates, craving, withdrawal symptoms, weight and cigarette consumption in smokers unable to quit. Adverse events were recorded systematically.Findings  Six months’ point prevalence abstinence rates were 31% and 16%[odds ratio = 2.3, confidence interval (CI) 95%: 1.4–3.7] in the B and Pl groups, respectively. Continuous abstinence rates were 41% (B) and 21% (P) with OR = 2.5 (CI 95%: 1.6–3.9) for weeks 4–7, and 25% (B) and 13% (P) with OR = 2.2 (CI 95%: 1.3–3.6) for weeks 4–26, respectively. Craving decreased significantly more with B than with Pl during treatment period, but there was no difference for total withdrawal symptoms score. Abstinent subjects gained significantly less weight at week 7 with B than with Pl. Low level of nicotine dependence, high motivation, absence of smoking‐related disease, long duration of previous quit attempts, male gender, low level of current alcohol problems and living as a couple were predictive of successful cessation. With the exception of marital status, no interaction was observed between any of these predictive factors and the efficacy of bupropion. More of those who continued smoking in the B group than the P group reduced their consumption by at least 50%.Conclusions  Sustained‐release bupropion is efficacious as an aid to smoking cessation in European smokers. No outcome predictors were identified that might indicate that certain subgroups of smokers would benefit more than others from treatment with bupropion.
Age, period and cohort influences on beer, wine and spirits consumption trends in the US National Alcohol Surveys
Authors: Kerr William C. , Greenfield Thomas K. , Bond Jason , Ye Yu , Rehm Jürgen 
Published: August 2004

ABSTRACTAims  To estimate the separate influences of age, period and cohort on the consumption of beer wine and spirits in the United States.Design  Linear age–period–cohort models controlling for demographic change with extensive specification testing.Setting  US general population 1979–2000.Measurements  Monthly average of past‐year consumption of beer, wine and spirits in five National Alcohol Surveys.Findings  The strongest cohort effects are found for spirits; cohorts born before 1940 are found to have significantly higher consumption than those born after 1946, with especially high spirits consumption for men in the pre‐1930s cohorts. Significant cohort effects are also found for beer with elevated consumption in the 1946–65 cohorts for men but in the pre‐1940 cohorts for women. Significant negative effects of age are found for beer and spirits consumption, although not for wine. Significant period effects are found for men's beer and wine consumption and for women's spirits consumption. Increased educational attainment in the population over time is associated with reduced beer consumption and increased wine consumption.Conclusions  Changing cohort demographics are found to have significant effects on beverage‐specific consumption, indicating the importance of controlling for these effects in the evaluation of alcohol policy effectiveness and the potential for substantial improvement in the forecasting of future beverage‐specific consumption trends, alcohol dependence treatment demand and morbidity and mortality outcomes.
Treatment of chronic hepatitis C in patients with drug dependence: time to change the rules?
Authors: Schaefer Martin , Heinz Andreas , Backmund Markus 
Published: August 2004

ABSTRACTAims Approximately 170 million people world‐wide are chronically infected with the hepatitis C virus (HCV). While the seroprevalence in the general population ranges between 0.2 and 2%, 50–90% of injection drug users are chronically HCV‐infected. However, most patients who are drug abusers are still excluded from treatment of chronic HCV infection with interferon (IFN)‐α. Due to the recent treatment advances resulting in sustained response rates between 50 and 80%, it becomes increasingly important to reflect the still existing contraindications and restrictions for IFN‐α treatment, especially for patients with intravenous drug use (IDU) with or without psychiatric comorbidity.Methods We reviewed clinical trials that focus on the treatment of chronic hepatitis C in patients with drug addiction published between 1987 and 2003.Findings Only seven clinical trials investigating HCV treatment among drug users were found: four open prospective uncontrolled trials and three controlled trials. Thus far, no trials using pegylated IFN‐α have been conducted. Data about sustained response and adherence in HCV‐infected methadone substituted patients were either comparable to control groups or to representative clinically controlled trials using the same treatment regimen (IFN‐α monotherapy or combined with ribavirin). Patients with former or present drug abuse seem more likely to discontinue treatment early. HCV‐infected IDUs tended to be older with higher inflammatory activity and stage of fibrosis when interferon treatment was started. Psychiatric comorbidity did not negatively influence adherence or treatment outcome.Conclusions There is no clinical evidence suggesting that HCV treatment with IFN‐α should be limited to IDUs or methadone substituted patients. However, more prospective controlled trials on HCV treatment for patients with IDU are needed to establish and apply new rules and guidelines.
Randomized controlled trial of brief cognitive–behavioural interventions for insomnia in recovering alcoholics
Authors: Currie Shawn R. , Clark Stewart , Hodgins David C. , El‐Guebaly Nady 
Published: August 2004

ABSTRACTAims  To test the efficacy of a cognitive–behavioural approach to treating disturbed sleep in abstinent alcoholics.Design  Sixty recovering alcoholics with insomnia were assigned randomly to individual therapy, self‐help with telephone support or waiting‐list control.Setting  Participants were volunteers recruited from out‐patient treatment programs and through the media.Measurements  Outcomes were assessed at post‐treatment, 3‐month and 6‐month follow‐ups using sleep diaries, the Pittsburgh Sleep Quality Index, wrist actigraphs and time‐line follow‐back interviews.Intervention  Five sessions of out‐patient cognitive–behavioural therapy for insomnia or a self‐help manual with five telephone support calls. Treatment duration was 7 weeks.Findings  Treated participants were significantly more improved than control participants on diary measures of sleep quality, sleep efficiency, awakenings and time to fall asleep. No significant differences between the individual therapy and self‐help treatment conditions on measures of insomnia severity were evident at post‐treatment. Self‐reported improvement in sleep was corroborated by clinician and spousal ratings of insomnia severity, but not by actigraph recordings of nocturnal activity. At 3‐ and 6‐month follow‐up assessments treatment gains were reasonably maintained in both treatment groups, although individual therapy was associated with a higher rate of clinically significant improvement. At the 6‐month follow‐up, 60% participants who were regular users of sedative medication at baseline discontinued the use of their medication. Treatment appeared to have little impact in preventing relapses to alcohol.Conclusions  Recovering alcoholics with insomnia can achieve better sleep by applying cognitive–behavioural strategies.
Is competition important to arctic zooplankton community structure?
Authors: Dzialowski Andrew R. , John O'Brien W. 
Published: August 2004

Summary1. Daphnia pulex and Daphnia middendorffiana are commonly found in the Toolik Lake region of arctic Alaska. These two species are very similar morphologically, although their natural distributions differ markedly: D. pulex is restricted to shallow ponds, while D. middendorffiana is widely distributed and found in a variety of ponds and lakes. We compared the reproductive capabilities of D. pulex and D. middendorffiana grown under similar resource conditions and in the absence of the invertebrate predator Heterocope septentrionalis. In situ life table and mesocosm experiments were conducted in Toolik Lake and Dam Pond, habitats that have historically contained natural populations of D. middendorffiana, but never D. pulex.2. Daphnia pulex exhibited a significantly higher net growth rate than D. middendorffiana in both life table and mesocosm experiments although D. pulex has never been found in either Toolik Lake or Dam Pond. Daphnia middendorffiana exhibited a negative net growth rate in Dam Pond, which had lower resource levels then Toolik Lake. Therefore, the smaller D. pulex appears to have a lower food threshold concentration than the larger D. middendorffiana.3. Our results indicate that D. pulex is a superior resource competitor in the Toolik Lake region. These results combined with distributional patterns suggest that the restricted distribution of D. pulex in these arctic lakes and ponds cannot be explained by resource competition alone. We suggest that in the presence of H. septentrionalis, predation is an important factor structuring arctic zooplankton communities in the Toolik Lake region.
Quantitative analysis of the importance of wind‐induced circulation for the spatial structuring of planktonic populations
Authors: Thackeray Stephen J. , Glen George D. , Jones Roger I. , Winfield Ian J. 
Published: August 2004

Summary1. Several studies have shown that wind‐induced water movements have an important effect on the spatial distribution of crustacean zooplankton. However, few attempts have been made to quantify the effect of physical processes on these broad‐scale patterns. Much of our understanding of this spatial structure has been based on the results of isolated surveys, which do not capture the dynamic nature of the pelagic environment.2. In this study, we have used a combination of high‐speed sampling (at a spatial resolution of 240 m) and spatial data analysis to quantify the factors influencing the horizontal spatial structure of the Daphnia galeata population in Windermere.3. The results show that lake‐wide circulation patterns, as indicated by water temperature, account for 29–47% of the basin‐scale spatial variance in D. galeata abundance. However, these patterns are highly dynamic and change in response to the prevailing weather. This lack of temporal persistence means that the results of single‐survey sampling campaigns must be interpreted with caution.
Response of American dippers (Cinclus mexicanus) to variation in stream water quality
Authors: Feck Jules , Hall Robert O. 
Published: August 2004

Summary1. Semi‐aquatic birds may be sensitive to altered water quality. While avian species are not used in the bioassessment of streams, they may complement the more common use of benthic macroinvertebrates and fish. We estimated the extent to which water quality can predict attributes of the populations of one common semi‐aquatic bird, the American dipper (Cinclus mexicanus).2. First, we estimated dipper presence/absence in relation to water quality as measured by a multimetric assessment index and individual bioassessment metrics. Second, we estimated dipper territory area and reproductive success in response to variation in water quality. We studied the diet, territory area and fecundity of dippers and sampled benthic macroinvertebrates, water chemistry and physical variables at 32 sites with and 17 sites without nesting dippers.3. Dipper presence was only weakly related to chemical, physical and commonly recorded bioassessment metrics such as per cent Ephemeroptera, Plecoptera and Trichoptera (%EPT). Dippers were strongly related to the abundance of their common prey, Drunella and Heptageniidae, which are only a small component of the commonly recorded bioassessment metrics. The variances in territory area and reproductive success were weakly predicted by water quality variables.4. Dipper presence reflected disturbance as measured by their common prey, showing that lower abundance of these stream invertebrates affected this semi‐aquatic bird. We suggest dipper presence/absence might be used in multimetric indices of biotic integrity for the bioassessment of streams.
Effects of food quality on life history of the rotifer Brachionus calyciflorus Pallas
Authors: Jensen Thomas C. , Verschoor Antonie M. 
Published: August 2004

Summary1. Herbivorous zooplankton face considerable temporal and spatial variation in food quality, to which they respond by adapting their life histories. Zooplankton may even take up mineral nutrients directly, and use these to counter the effects of algal nutrient limitation (mineral compensation). This study examined the life history of the rotifer Brachionus calyciflorus fed phosphorus‐, and nitrogen‐limited Scenedesmus obliquus (Chlorophyta), and investigated whether B. calyciflorus was capable of mineral compensation.2. Both phosphorus‐ and nitrogen‐limited algae gave similar life history responses: somatic growth and reproduction were reduced, whereas lifespan remained unaffected.3. No evidence was found for mineral compensation in B. calyciflorus in relation to detrimental life history effects, so mineral compensation does not seem to be relevant for this species under field conditions.4. The similarity in life history responses of B. calyciflorus and the low levels of ω‐3 PUFAs in both phosphorus‐ and nitrogen‐depleted algae suggest that ω‐3 PUFAs were limiting to B. calyciflorus, although other (bio)chemicals or mineral nutrients may also have been important.5. No trade‐off was observed between life span and reproduction during algal nutrient limitation. Reduced population growth rates of B. calyciflorus were caused by shorter reproductive periods.
Effects of habitat complexity on benthic assemblages in a variable environment
Authors: Taniguchi Hiromi , Tokeshi M. 
Published: August 2004

Summary1. Habitat complexity is thought to exert a significant influence on ecological communities, but its operation under variable natural conditions is not well understood, particularly in freshwater. To elucidate the role of habitat complexity, in particular the fractal structure of surface irregularity, in a stream system, field colonisation experiments were conducted at three times of year (summer, winter and spring) using natural substrates with different levels of fractal dimension in a small coastal mountain stream of southern Japan.2. In the winter experiment, comparison was also made between the standard (control) treatment and the resource‐preconditioning treatment whereby experimental plates were conditioned in the natural stream environment to allow the accumulation of potential food resources (algae and detritus) for 1 month prior to the experiment.3. Species abundance patterns observed at different times of year showed little systematic variation with levels of habitat complexity but largely followed the patterns expected from, or lying in between, the Random Assortment model and the random fraction model.4. Taxon richness and density increased with habitat complexity in all seasons except for density in spring. Different taxa showed different patterns of change with habitat complexity, which also varied with seasons. Biomass of invertebrates showed no systematic trend with an increase in habitat complexity.5. Chlorophyll‐a concentrations tended to be lower in more complex habitats, particularly in summer. In contrast, fine particulate organic matter (FPOM) tended to increase with habitat complexity. However, the relationship between these potential food resources and invertebrate assemblages remain unclear.6. While there were no significant differences in taxon richness and biomass of invertebrates between the resource‐preconditioning and the control treatment, density was higher in the former than in the latter. The abundance of relatively large, surface‐dwelling animals showed more marked temporal variation over the entire period of colonisation in the resource‐preconditioning treatment than in the control treatment.7. Body size of invertebrates tended to decline with fractal complexity, indicating that crevice sizes could affect habitat use by benthic animals of different sizes. In addition, body size was larger in the resource‐preconditioning treatment than in the control treatment, suggesting that body size in invertebrate assemblages was controlled by a mixture of factors. Thus, the present study demonstrates that habitat structure affects benthic invertebrate assemblages in a complex manner.
Distribution of Daphnia in a trade‐off between food and temperature: individual habitat choice and time allocation
Authors: Kessler Kirsten 
Published: August 2004

Summary1. In a thermally stratified water column with a deep‐water algal maximum, Daphnia face a trade‐off between food (high fecundity) and temperature (fast development). Recent studies showed that Daphnia populations move up and down the entire water column to take advantage of both, but the proportion of time allocated by individuals to the epilimnion, metalimnion and hypolimnion with their specific food and temperature conditions is not yet known.2. In a system of 1 m deep, vertical perspex tubes, I established three temperature gradients with 2, 5 and 10 °C differences between the surface (epilimnion) and the bottom layer (hypolimnion). Algae were added to the hypolimnion to simulate a deep‐water algal maximum.3. The migration behaviour of individual neonate and egg‐bearing Daphnia hyalina × galeata was monitored in order to measure the proportions of time the individuals allocated to the different vertical habitats and to assess the frequency of their shifts between epilimnion and hypolimnion.4. Neonates stayed continuously at the surface, taking advantage of the higher temperature, possibly because feeding was less important for them because of egg yolk reserves. In contrast, egg‐bearing females spent more time feeding in the hypolimnion when the temperature gradient was weak, but also migrated into the epilimnion to take advantage of the higher temperature. In the steepest temperature gradient, the egg‐bearing females either shifted between epilimnion and hypolimnion, or dwelled constantly in the metalimnion with intermediate conditions.