A Longitudinal Investigation of Lower-Risk Gambling Limits in the Canadian National Study

Recent years have seen increased attention given to identifying and describing the levels of gambling participation that confer a risk of harm in order to generate public health advice regarding lower-risk gambling. However, most of the existing literature has failed to explicitly assess these limits in a prospective manner. The purpose of this study is to employ a methodology consistent with prior investigations to evaluate the level of gambling participation associated with an increased risk of future gambling-related harm. Using data from the Alberta Gambling Research Institute's National Project Online Panel Survey, risk ratios and Receiver Operating Characteristic (ROC) analyses were used to determine the relative risk of gambling-related harm associated with participating in a greater number of gambling formats, gambling more days per month, and spending a greater proportion of income gambling. Prospective lower-risk limits were largely consistent with those identified in previous cross-sectional analyses (e.g., no more than two gambling formats, no more than once a week), with the exception that higher limits were found for the percent of household income spent gambling (3.4-6.4% vs. 1%). We advise that future research on lower-risk gambling limits consider the use of more granular assessment instruments and prospective methods to more closely evaluate the association between gambling participation and gambling harm.

Trends of repeated emergency department visits among adolescents and young adults for substance use: A repeated cross-sectional study

Emergency Department (ED) visits for substance-related concerns among young people have been increasing in recent years. Understanding the factors related to repeated ED visits (two or more ED visits per year) for substance use concerns among young people is critical to developing a more efficient mental healthcare system that does not overburden ED and that provides efficient care for substance use patients. This study examined trends of substance use-related ED visits and factors related to repeated ED visits (two or more ED visits per year, in comparison to one ED visit per year) among adolescents and young adults (aged 13 to 25 years) in the province of Ontario, Canada. Binary logistic regression models were conducted to examine associations between hospital-related factors (hospital size, urbanicity, triage level, ED wait time) and visit status (2+ vs 1 ED visit/year), controlling for patient characteristics (age/sex). A population-based, repeated cross-sectional data over a 10-year period (2008, 2013, and 2018) was used. The proportion of substance use-related repeated ED visits significantly and consistently increased in the year 2013 and 2018 compared to 2008 (2008 = 12.52%, 2013 = 19.47%, 2018 = 20.19%). Young adult, male, medium-sized hospital, urban location, wait times longer than 6 hours, and symptom severity was associated with increased numbers of repeated ED visits. Furthermore, polysubstance use, opioid use, cocaine use, and stimulant use were strongly associated with repeated ED visits compared with the use of substances such as cannabis, alcohol and sedatives. Current findings suggest that repeated ED visits for substance use concerns could be reduced by policies that reinforce evenly distributed mental health and addiction treatment services across the provinces in rural areas and small hospitals. These services should put special efforts into developing specific (e.g., withdrawal/treatment) programming for substance-related repeated ED patients. The services should target young people using multiple psychoactive substances, stimulants and cocaine.

Antimicrobial resistance profile of Escherichia coli isolated from poultry litter

Antimicrobial resistance is a threat to animal and human health. As a commensal and zoonotic bacterium, Escherichia coli has the potential to be a pathogenic source of antimicrobial resistance. The purpose of this study aimed to investigate the antimicrobial resistance profile of E. coli isolated from litter collected from pens in a broiler chicken experiment. E. coli was isolated from litter samples (n = 68 isolates) of 16 pens housing broilers to d 53 of age. Resistance to 10 antimicrobials was observed by disc diffusion. The presence of 23 antimicrobial and heavy metal resistance genes, O serogroups, and avian pathogenic E. coli (APEC-like) minimal predictor genes were identified through PCR. E. coli isolates presented the greatest resistance to cephalothin (54.4%), tetracycline (27.9%), streptomycin (29.4%), ampicillin (20.6%), colistin (13.2%), sulphonamides (8.8%), and imipenem (1.5%). Multidrug resistance to at least 3 antimicrobials was observed in 22.1% of isolates. The identified O-types of the E. coli isolates were O15, O75, O78, and O91. There was a greater likelihood that the genes groEL, aph(3)IA, silP, sull, aadA, qacEdelta1, iroN, ompTp, and hlyF were present in isolates that exhibited ampicillin resistance (P ≤ 0.05). There was a greater likelihood that the groEL gene was present in isolates resistant to ampicillin, colistin, tetracycline, sulphonamides, or cephalothin (P ≤ 0.05). Further characterizing E. coli antimicrobial resistance is essential and aids in developing effective solutions, thereby furthering the One Health objective.

In search of lower risk gambling levels using behavioral data from a gambling monopolist

BACKGROUND AND AIMS

Lower-risk recommendations for avoiding gambling harm have been developed as a primary prevention measure, using self-reported prevalence survey data. The aim of this study was to conduct similar analyses using gambling company player data.

METHODS

The sample (N = 35,753) were Norsk Tipping website customers. Gambling indicators were frequency, expenditure, duration, number of gambling formats and wager. Harm indicators (financial. social, emotional, harms in two or more areas) were derived from the GamTest self-assessment instrument. Receiver operating characteristics (ROC) curves were performed separately for each of the five gambling indicators for each of the four harm indicators.

RESULTS

ROC areas under the curve were between 0.55 and 0.68. Suggested monthly lower-risk limits were less than 8.7 days, expenditure less than 54 €, duration less than 72-83 min, number of gambling formats less than 3 and wager less than 118-140€. Most risk curves showed a rather stable harm level up to a certain point, from which the increase in harm was fairly linear.

DISCUSSION

The suggested lower-risk limits in the present study are higher than limits based on prevalence studies. There was a significant number of gamblers (5-10%) experiencing harm at gambling levels well below the suggested cut-offs and the risk increase at certain consumption levels.

CONCLUSIONS

Risk of harm occurs at all levels of gambling involvement within the specific gambling commercial environment assessed in an increasingly available gambling market where most people gamble in multiple commercial environments, minimizing harm is important for all customers.

Messenger effects in COVID-19 communication: Does the level of government matter?

Public efforts to limit the spread of the coronavirus rely on motivating people to cooperate with the government. We test the effectiveness of different governmental messengers to encourage preventive health actions. We administered a survey experiment among a sample (n = 1,545) of respondents across the United States, presenting them with the same social media message, but experimentally varying the government sender (i.e., Federal, State, County, a combination of Federal + County, and a control condition) to test whether local relevance influences messaging efficacy. We find that in an information saturated environment the messenger does not matter. There is, however, variation in treatment response by partisanship, education, income, and the degree to which respondents are affected by the pandemic. While the main effect of the level of government on intended behavior is null, public health organizations are universally perceived as more trustworthy, relevant, and competent than anonymous messengers.

Attributable fractions for substance use in relation to crime

AIMS

Building upon an existing methodology and conceptual framework for estimating the association between the use of substances and crime, we calculated attributable fractions that estimate the proportion of crimes explained by alcohol and six other categories of psychoactive substances.

DESIGN

Cross-sectional surveys.

SETTING

Canadian federal correctional institutions.

PARTICIPANTS

Canadian men (n = 27 803) and women (n = 1335) offenders who began serving a custodial sentence in a Canadian federal correctional institution between 2006 and 2016.

MEASUREMENTS

Offenders completed the computerized assessment of substance abuse, a self-report tool designed to assess (1) whether the offence for which they were convicted would have occurred had they not been intoxicated from alcohol or another substance, (2) whether they committed the offence to support their alcohol or other substance use and (3) whether they were dependent on alcohol (alcohol dependence scale) or another substance (drug abuse screening test). Offences were grouped into four mutually exclusive categories: violent crimes, non-violent crimes, impaired driving and substance-defined crimes. This study focused on violent and non-violent crime categories. Substances assessed were: alcohol, cannabis, opioids, other central nervous system (CNS) depressants, cocaine, other CNS stimulants and other substances.

FINDINGS

According to offender self-report, 42% of all violent and non-violent crime would probably not have occurred if the perpetrator had not been under the influence of, or seeking, alcohol or other substances. Between 2006 and 2016, 20% of violent crimes and 7% of non-violent crimes in Canada were considered attributable to alcohol. In contrast, all other psychoactive substance categories combined were associated with 26% of all violent crime and 25% of non-violent crime during the same time-frame.

CONCLUSIONS

Attributable fraction analyses show that more than 42% of Canadian crime resulting in a custodial sentence between 2006 and 2016 would probably not have occurred if the perpetrator had not been under the influence of or seeking alcohol or other drugs. Attributable fractions for alcohol and substance-related crime are a potentially useful resource for estimating the impact of alcohol and other substances on crime.

Psychotic disorder and cannabis use: Canadian hospitalization trends, 2006-2015

INTRODUCTION

Given the recent and impending changes to the legal status of nonmedical cannabis use in Canada, understanding the effects of cannabis use on the health care system is important for evaluating the impact of policy change. The aim of this study was to examine pre-legalization trends in hospitalizations for mental and behavioural disorders due to the use of cannabis, according to demographics factors and clinical conditions.

METHODS

We assessed the total number of inpatient hospitalizations for psychiatric conditions with a primary diagnosis of a mental or behavioural disorder due to cannabis use (ICD-10-CA code F12) from the Hospital Mental Health Database for ten years spanning 2006 to 2015, inclusive. We included hospitalizations from all provinces and territories except Quebec. Rates (per 100 000 persons) and relative proportions of hospitalizations by clinical condition, age group, sex and year are reported.

RESULTS

Between 2006 and 2015, the rate of cannabis-related hospitalizations in Canada doubled. Of special note, however, is that hospitalizations during this time period for those with the clinical condition code "mental and behavioural disorders due to use of cannabinoids, psychotic disorder" (F12.5) tripled, accounting for almost half (48%) of all cannabis-related hospitalizations in 2015.

CONCLUSION

Further research is required to investigate the reasons for the increase in hospitalizations for cannabis-related psychotic disorder. The introduction of high-potency cannabinoid products and synthetic cannabinoids into the illicit market are considered as possible factors.

Gambling Self-Control Strategies: A Qualitative Analysis

There is limited research exploring the perceptions of people who gamble on the self-control strategies used to limit their gambling. This qualitative study examines self-control strategies used to limit money spent gambling, frequency of gambling, and time spent gambling. A total of 56 people who gamble (27 males and 29 females) participated in nine focus groups and five individual interviews in Montreal, Calgary, and Toronto (Canada). Self-control strategies used to limit their gambling expenditure were more common than frequency or time limiting strategies. Strategies to limit expenditure included: restricting access to money; keeping track of money allocated to gambling activities; and avoiding certain types of gambling activities. Various contextual factors were identified to influence those strategies, including social influences; winning or losing; using substances. Findings from this study emphasize the importance of communicating clear gambling limits to people who gamble, as well as the value of developing individual self-control strategies to limit frequency, time and money spent gambling.

Artificial intelligence, bureaucratic form, and discretion in public service

This article examines the relationship between Artificial Intelligence (AI), discretion, and bureaucratic form in public organizations. We ask: How is the use of AI both changing and changed by the bureaucratic form of public organizations, and what effect does this have on the use of discretion? The diffusion of information and communication technologies (ICTs) has changed administrative behavior in public organizations. Recent advances in AI have led to its increasing use, but too little is known about the relationship between this distinct form of ICT and to both the exercise of discretion and bureaucratic form along the continuum from street- to system-levels. We articulate a theoretical framework that integrates work on the unique effects of AI on discretion and its relationship to task and organizational context with the theory of system-level bureaucracy. We use this framework to examine two strongly differing cases of public sector AI use: health insurance auditing, and policing. We find AI’s effect on discretion is nonlinear and nonmonotonic as a function of bureaucratic form. At the same time, the use of AI may act as an accelerant in transitioning organizations from street- and screen-level to system-level bureaucracies, even if these organizations previously resisted such changes.

Novel psychoactive substances: What educators need to know

Novel psychoactive substances (NPS) are synthetic, psychoactive drugs that are generally not under international regulatory control. NPS are frequently sold as alternatives to classic "street drugs" such as ecstasy or LSD. However, little is known about their pharmacology and toxicity and they therefore pose unknown health risks. Further, risk for harms are elevated because users often do not know what they are taking, and therefore cannot predict dose, potency, or other potential properties.

Detecting a signal in the noise: monitoring the global spread of novel psychoactive substances using media and other open-source information

OBJECTIVE

To determine the feasibility and utility of using media reports and other open-source information collected by the Global Public Health Intelligence Network (GPHIN), an event-based surveillance system operated by the Public Health Agency of Canada, to rapidly detect clusters of adverse drug events associated with 'novel psychoactive substances' (NPS) at the international level.

METHODS AND RESULTS

Researchers searched English media reports collected by the GPHIN between 1997 and 2013 for references to synthetic cannabinoids. They screened the resulting reports for relevance and content (i.e., reports of morbidity and arrest), plotted and compared with other available indicators (e.g., US poison control center exposures). The pattern of results from the analysis of GPHIN reports resembled the pattern seen from the other indicators.

CONCLUSIONS

The results of this study indicate that using media and other open-source information can help monitor the presence, usage, local policy, law enforcement responses, and spread of NPS in a rapid effective way. Further, modifying GPHIN to actively track NPS would be relatively inexpensive to implement and would be highly complementary to current national and international monitoring efforts.

Effectiveness of brief interventions as part of the Screening, Brief Intervention and Referral to Treatment (SBIRT) model for reducing the nonmedical use of psychoactive substances: a systematic review

BACKGROUND

The purpose of this systematic review is to assess the effectiveness of brief interventions (BIs) as part of the Screening, Brief Intervention, and Referral to Treatment (SBIRT) model for reducing the nonmedical use of psychoactive substances.

METHODS

Bibliographic databases (including MEDLINE, Embase, The Cochrane Library, CINAHL, and PsycINFO to April 2012) and gray literature sources were searched. We included randomized controlled trials that opportunistically screened adolescents or adults and then provided a one-to-one, verbal BI to those at risk of substance-use harm. Of interest was the nonmedical use of psychoactive substances (for example, drugs prohibited by international law), excluding alcohol, nicotine, and caffeine. Interventions comprised four or fewer sessions and were compared with no/delayed intervention or provision of information only. Studies were assessed for bias using the Cochrane risk of bias tool. Results were synthesized narratively. Evidence was interpreted according to the GRADE framework.

RESULTS

We identified 8,836 records. Of these, five studies met our inclusion criteria. Two studies compared BI with no BI, and three studies compared BI with information only. Studies varied in characteristics such as substances targeted, screening procedures, and BI administered. Outcomes were mostly reported by a single study, leading to limited or uncertain confidence in effect estimates.

CONCLUSIONS

Insufficient evidence exists as to whether BIs, as part of SBIRT, are effective or ineffective for reducing the use of, or harms associated with nonmedical use of, psychoactive substances when these interventions are administered to nontreatment-seeking, screen-detected populations. Updating this review with emerging evidence will be important.

TRIAL REGISTRATION

CRD42012002414.

Effectiveness of brief interventions as part of the screening, brief intervention and referral to treatment (SBIRT) model for reducing the non-medical use of psychoactive substances: a systematic review protocol

BACKGROUND

There is a significant public health burden associated with substance use in Canada. The early detection and/or treatment of risky substance use has the potential to dramatically improve outcomes for those who experience harms from the non-medical use of psychoactive substances, particularly adolescents whose brains are still undergoing development. The Screening, Brief Intervention, and Referral to Treatment model is a comprehensive, integrated approach for the delivery of early intervention and treatment services for individuals experiencing substance use-related harms, as well as those who are at risk of experiencing such harm.

METHODS

This article describes the protocol for a systematic review of the effectiveness of brief interventions as part of the Screening, Brief Intervention, and Referral to Treatment model for reducing the non-medical use of psychoactive substances. Studies will be selected in which brief interventions target non-medical psychoactive substance use (excluding alcohol, nicotine, or caffeine) among those 12 years and older who are opportunistically screened and deemed at risk of harms related to psychoactive substance use. We will include one-on-one verbal interventions and exclude non-verbal brief interventions (for example, the provision of information such as a pamphlet or online interventions) and group interventions. Primary, secondary and adverse outcomes of interest are prespecified. Randomized controlled trials will be included; non-randomized controlled trials, controlled before-after studies and interrupted time series designs will be considered in the absence of randomized controlled trials. We will search several bibliographic databases (for example, MEDLINE, EMBASE, CINAHL, PsycINFO, CORK) and search sources for grey literature. We will meta-analyze studies where possible. We will conduct subgroup analyses, if possible, according to drug class and intervention setting.

DISCUSSION

This review will provide evidence on the effectiveness of brief interventions as part of the Screening, Brief Intervention, and Referral to Treatment protocol aimed at the non-medical use of psychoactive substances and may provide guidance as to where future research might be most beneficial.

Cortisol Rise Following Awakening Among Problem Gamblers: Dissociation from Comorbid Symptoms of Depression and Impulsivity

Gambling pathology has been associated with elevated levels of distress, depression and impulsivity. The present investigation assessed whether these behavioral features would be evident among problem gamblers as they are among pathological gamblers. As well, given that gambling has been associated with increased life stress, as an objective index of ongoing distress, elevations of morning cortisol levels were assessed in problem and pathological gamblers relative to recreational gamblers, and their relations to depressive symptoms and impulsivity were assessed. Recreational, problem, and pathological gamblers (N = 140) completed the Beck Depression Inventory and the Barratt Impulsiveness Scale-11, and provided saliva samples at awakening, 30 min, 3.5 h, and 5.5 h afterward. Consistent with the view that problem and pathological gambling are associated with elevated life stressors, the rise of morning cortisol from awakening to 30 min following awakening was greater than in recreational gamblers. Heightened impulsivity was evident among both problem and pathological gamblers, whereas depressive symptoms were only evident among pathological gamblers. In neither instance were these psychological indices related to the morning cortisol rise. Indeed, increased depressive symptoms were not evident among problem gamblers, despite the fact that elevated morning cortisol levels were evident. The elevated morning cortisol rise may be secondary to gambling problems or distress related to gambling problems. Furthermore, the sustained morning cortisol elevations may be indicative of allostatic overload, and could potentially be a harbinger for potential health risks among problematic gamblers.

Self-perceptions of dispositional luck: relationship to DSM gambling symptoms, subjective enjoyment of gambling and treatment readiness

In the present study, we examined whether having a gambling disorder is related to: (a) the personality trait of perceived personal luck and (b) subjective enjoyment associated with placing bets. We also examined whether the presence or absence of disordered gambling and wagering enjoyment are related to probability of treatment entry. In 2001, we surveyed 82 young adults at the University of Windsor who gambled, but were not in treatment. They completed measures assessing symptoms of pathological gambling (American Psychiatric Association [APA], 1994), dispositional luck (Steenbergh, Meyers, May, and Whelan, 2002), enjoyment of gambling (Ben-Tovim, Esterman, Tolchard, and Battersby, 2001), and attitudes toward treatment (adapted from Fisher and Turner, 1970). Results showed elevated perceptions of personal luck, enjoyment of gambling, and more negative attitudes toward seeking treatment among those who exhibited sub-clinical levels of disordered gambling (n = 41) compared to recreational gamblers (n = 41). Other results showed that, after controlling for the effects of personal luck, the strength of the positive relationship between level of disordered gambling and subjective pleasure of wagering was diminished. Removing the effects of personal luck also weakened the positive association between having a gambling problem and having a negative attitude toward seeking treatment. In light of these results, we suggest cognitive interventions that seek to prevent and treat problematic wagering in early stage gamblers might be efficacious to the extent to which they can modify these young people's belief that they are charmed by high levels of dispositional luck.

Risk factors for invasive meningococcal disease in southern Queensland, 2000-2001

AIM

The aim of this paper is to describe the risk factors for invasive meningococcal disease (IMD) in southern Queensland.

METHODS

A case control study during the calendar years 2000-2001 was undertaken.

RESULTS

Eighty-four laboratory-confirmed cases of IMD were notified. Four patients died and were excluded from the present study. Sixty-two (78%) eligible cases and 79 controls selected from the same age group and medical practice as cases, were interviewed. Univariate analysis found that IMD was associated with sharing bedrooms with two or more people (odds ratio (OR) 4.3; 95% confidence interval (CI) 1.2-17.0, P = 0.01), any exposure to tobacco smoke (smoker or passive exposure; OR 2.3; 95% CI 1.1-4.8, P = 0.02), passive exposure to tobacco smoke (OR 2.4; 95% CI 1.0-5.6, P = 0.03) and recent upper respiratory tract infection (OR 1.9, 95% CI 0.9-4.1, P = 0.06). Children who were breast-fed were less likely to develop IMD (OR 0.3; 95% CI 0.1-1.1, P = 0.04). Attendance at a childcare centre was not associated with an increased risk of IMD. In multivariate analysis, IMD was associated with children under 6 years of age who shared a bedroom with two or more people (OR 7.4; 95% CI 1.5-36.1, P = 0.01) or who had a primary carer who smoked (OR 9.1; 95% CI 2.1-39.9, P = 0.003).

DISCUSSION

This is the second Australian study that identifies links between risk of IMD and exposure to cigarette smoke. The risk of IMD in young children could be further reduced if primary caregivers did not smoke. This information may contribute a new perspective to antismoking campaigns.

Design, docking, and evaluation of multiple libraries against multiple targets

We present a general approach to the design, docking, and virtual screening of multiple combinatorial libraries against a family of proteins. The method consists of three main stages: docking the scaffold, selecting the best substituents at each site of diversity, and comparing the resultant molecules within and between the libraries. The core "divide-and-conquer" algorithm for side-chain selection, developed from an earlier version (Sun et al., J Comp Aided Mol Design 1998;12:597-604), provides a way to explore large lists of substituents with linear rather than combinatorial time dependence. We have applied our method to three combinatorial libraries and three serine proteases: trypsin, chymotrypsin, and elastase. We show that the scaffold docking procedure, in conjunction with a novel vector-based orientation filter, reproduces crystallographic binding modes. In addition, the free-energy-based scoring procedure (Zou et al., J Am Chem Soc 1999;121:8033-8043) is able to reproduce experimental binding data for P1 mutants of macromolecular protease inhibitors. Finally, we show that our method discriminates between a peptide library and virtual libraries built on benzodiazepine and tetrahydroisoquinolinone scaffolds. Implications of the docking results for library design are explored.

Esophageal reconstruction for benign disease: self-assessment of functional outcome and quality of life

BACKGROUND

Little information exists regarding functional outcome and quality of life after esophagectomy and subsequent esophageal reconstruction for benign disease as evaluated by the patients themselves.

METHODS

Eighty-one patients completed a combined two-part questionnaire regarding esophageal function and quality of life (MOS SF-36) a median of 9.8 years (range, 10 months to 18.9 years) after esophageal reconstruction for benign disease. There were 43 men (53.1%) and 38 women (46.9%). Median age at time of esophageal reconstruction was 51 years (range, 6 to 78 years). Intestinal continuity was established with stomach in 58 patients (71.6%), colon in 16 patients (19.8%), and small bowel in 7 patients (8.6%).

RESULTS

Dysphagia to solids was present in 48 patients (59.3%) and 27 patients (33.3%) required at least one postoperative dilatation. Heartburn was present in 50 patients (61.7%) which required medication for control in 37 patients (45.7%). The number of meals per day was three to four in 58 patients (71.6%), more than four in 15 patients (18.5%), less than three in 6 patients (7.4%), and unknown in 2 patients (2.5%). The size of each meal was smaller than preoperatively in 46 patients (56.8%), larger in 22 patients (27.2%), unchanged in 12 patients (14.8%), and unknown in 1 patient (1.2%). The number of bowel movements per day increased in 37 patients (45.7%), was unchanged in 36 patients (44.4%), and decreased in 8 patients (9.9%). Resection for perforation was associated with smaller postoperative meals compared with resection for stricture (p < 0.05). Age, sex, and type of esophageal reconstruction did not affect late functional outcome. Regarding quality of life, physical functioning, social functioning, and health perception were decreased (p < 0.05). No significant change was observed in role-physical, mental health, bodily pain, energy/fatigue, and role-emotional scores.

CONCLUSIONS

Self-assessment of postoperative esophageal symptoms after esophagectomy and reconstruction for benign disease demonstrates that symptoms are frequently present at long-term follow-up and unaffected by the type of reconstruction.

Esophageal reconstruction for benign disease: early morbidity, mortality, and functional results

BACKGROUND

Esophagectomy for benign disease is performed infrequently. We reviewed the Mayo Clinic's experience with patients who required esophageal reconstruction for benign esophageal disease.

METHODS

From March 1956 to October 1997, all patients who required resection and reconstruction for a benign condition of the esophagus were reviewed.

RESULTS

There were 255 patients (141 male, 114 female). Median age was 55 years (range, 2 to 100). The original diagnosis was an esophageal stricture in 108 patients (42%), primary motility disorder in 84 (33%), perforation in 36 (14%), hiatal hernia in 18 (7%), and other in 9 (4.0%). Reconstruction was with stomach in 168 patients (66%), colon in 70 (27%), and small bowel in 17 (7%). The anastomosis was intrathoracic in 144 patients (57%) and cervical in 111 (43%). There were 13 postoperative deaths (mortality 5%); 142 patients (56%) had at least one complication. Median hospitalization was 14 days (range, 6-95 days). Follow-up was complete in 226 patients (88.6%) for a median of 52 months (range, 1 month to 29 years). A total of 175 patients (77.4%) were improved. Functional results were classified as excellent in 72 patients (31.8%), good in 23 (10.2%), fair in 80 (35.4%), and poor in 51 (22.6%).

CONCLUSIONS

Esophageal reconstruction for benign disease resulted in functional improvement in a majority of patients. It can be done with low mortality and acceptable morbidity. Early morbidity is adversely affected by the diagnosis of perforation and the route through which the conduit is placed. Late functional outcome is adversely affected by the diagnosis of paraesophageal hernia and a cervical anastomosis.

Videoendoscopic thoracic aorta-to-femoral artery bypass in the pig

BACKGROUND

The thoracoscopic approach to the aorta has the advantages of easy aortic dissection, excellent inflow, improved exposure in the thorax without insufflation, and ability to employ both laparoscopic and traditional instruments. Our aim was to develop a thoracoscopic technique for descending thoracic aorta-to-femoral artery bypass (TAFB) in the pig that results in acceptable short-term survival and graft patency.

MATERIALS AND METHODS

Thoracoscopic TAFB was performed in 11 pigs. Using two-lung ventilation, the animals were placed in a 45 degrees left lateral semidecubitus position. A fan lung retractor, two dissecting ports, intercostal artery loops, and camera were placed through five 10- to 20-mm thoracoscopic incisions. After aortic dissection, an 8-mm graft was passed through a retroperitoneal tunnel. Rumel tourniquets were used for aortic occlusion after placement of a shunt. End-to-side endoscopic anastomosis was completed with knots tied extracorporeally. The left femoral anastomosis was completed under direct vision. Duplex ultrasound of the graft was done on postoperative days 1, 3, and 7.

RESULTS

Thoracoscopic TAFB was completed in all animals. Mean aortic anastomosis time was 57 min (range, 34-145); and mean cross-clamp time, 74 min (range, 53-155). Mean operative time was 310 min; the first six operations lasted longer than the last five (338 min vs 276 min, P < 0.04). Average blood loss was 611 ml (range, 250-1300). Two animals died due to anesthetic complications. One (11%) of the nine surviving pigs died on day 2 due to bleeding. Complications were paraplegia in one (11%) and graft thrombosis in another (11%).

CONCLUSIONS

Videoendoscopic TAFB can be completed in pigs with acceptable short-term patency and survival. Further experience in thoracoscopic techniques can make TAFB a feasible and low-risk option for selected patients with aortoiliac occlusive disease.

High throughput protein fold identification by using experimental constraints derived from intramolecular cross-links and mass spectrometry

We have used intramolecular cross-linking, MS, and sequence threading to rapidly identify the fold of a model protein, bovine basic fibroblast growth factor (FGF)-2. Its tertiary structure was probed with a lysine-specific cross-linking agent, bis(sulfosuccinimidyl) suberate (BS(3)). Sites of cross-linking were determined by tryptic peptide mapping by using time-of-flight MS. Eighteen unique intramolecular lysine (Lys-Lys) cross-links were identified. The assignments for eight cross-linked peptides were confirmed by using post source decay MS. The interatomic distance constraints were all consistent with the tertiary structure of FGF-2. These relatively few constraints, in conjunction with threading, correctly identified FGF-2 as a member of the beta-trefoil fold family. To further demonstrate utility, we used the top-scoring homolog, IL-1beta, to build an FGF-2 homology model with a backbone error of 4.8 A (rms deviation). This method is fast, is general, uses small amounts of material, and is amenable to automation.

NMDA and AMPA glutamate receptor subtypes in the thoracic spinal cord in lean and obese-diabetic ob/ob mice

Quantitative autoradiography was used to characterise the binding of selective radiolabelled antagonists for the N-methyl-D-aspartate (NMDA) receptor and the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor in the dorsal, intermediate and ventral subregions of the grey matter of the upper thoracic spinal cord in male and female lean and obese-diabetic (ob/ob) mice. The density of binding sites for both receptor subtypes was greater in diabetic mice, in all three subregions of the grey matter, than the corresponding subregions in the lean mice. The affinity of the binding site for the NMDA antagonist was significantly higher in obese mice than lean mice, consistent with the presence of two subpopulations of NMDA receptors with different ligand binding affinities in obese mice. The increase in expression of the glutamate receptor subtypes, and altered ligand affinity for the NMDA receptor subtype in the obese mice may be causally involved in the peripheral neuropathies which can accompany diabetes mellitus.

Effect of sympathectomy on the expression of NMDA receptors in the spinal cord

The expression of NMDA receptors in the intermediolateral (IML) region of the upper thoracic spinal cord, was studied in 3 week old rats. The effect of section of the cervical sympathetic nerve on neuronal cell number and receptor expression was examined up to two weeks after the operation. Age-matched sham-operated and unoperated animals were used as controls. It was shown using quantitative autoradiography with the NMDA receptor antagonist [(3)H]MK-801 (dizocilpine maleate), that there was a marked downregulation of receptors in all groups of animals, beginning at approximately 4 weeks of age. However after sympathectomy, which resulted in the death of 44% of neurones in the IML by 7 days, there was a significant increase in receptor density per neurone compared to sham-operated controls. In the control animals there was a significant increase in the Kd value of the binding between 21 and 24 days after birth indicating an increased expression of a low affinity receptor, but no such increase was seen after axotomy. The results are consistent with two populations of NMDA receptors being transiently expressed in the IML in developing animals, and the higher affinity receptor being down-regulated between 4 and 5 weeks of age. The presence of the high affinity receptor subtype may predispose neurones to die after axotomy.

Laparoscopic transureteroureterostomy: demonstration of its feasibility in swine

PURPOSE

To evaluate the feasibility of laparoscopic transureteroureterostomy (TUU) in a porcine model.

MATERIALS AND METHODS

Nine female pigs had bilateral ureteral stents placed 3 weeks prior to surgery. At surgery, a left-to-right laparoscopic TUU was performed. Ureteral stents were placed across the anastomosis in seven cases. Six weeks after surgery, the stents were removed. After an additional 3 weeks, an excretory urogram, retrograde ureteropyelogram, and ureteroscopic examination of the anastomosis were performed. Serum creatinine assay and urine cultures were performed at regular intervals. Antibiotic prophylaxis was used for 1 week after each procedure.

RESULTS

Of the nine animals, eight underwent successful laparoscopic TUU. Excretory urograms revealed prompt function and washout in all these cases. One animal developed an anastomotic stricture; in this animal, the ureters had remained nondilated after initial stent placement. Serum creatinine values remained within the normal range for all animals undergoing successful surgery. Additional complications included one urinary tract infection and one postoperative ileus, which were treated without difficulty. The operative time ranged from 2.5 to 6 hours, with shorter procedures later in the series.

CONCLUSIONS

Laparoscopic TUU is practical in the porcine model. It may prove to be an alternative to an open TUU in patients with lower ureteral lesions when ureteroneocystostomy is not feasible.

Lack of association between genetic variation in the beta3-adrenergic receptor gene and insulin resistance in patients with coronary heart disease

The beta-adrenergic system plays a critical role in regulating lipolysis and thermogenesis. Recent studies have suggested that a missense Trp64Arg mutation in the beta3-adrenergic receptor gene is involved in visceral obesity and insulin resistance. We investigated the effect of this mutation on insulin resistance in patients with angiographically documented coronary heart disease ([CHD]n = 137) and normal subjects (n = 188). Plasma glucose and insulin responses to a 75-g oral glucose tolerance test and insulin resistance measured by the insulin suppression test, were determined in 58 (42%) patients with CHD and 121 (64%) controls. The genotype and allele frequency of the beta3-adrenergic receptor did not differ between patients with CHD and controls. The blood pressure, body mass index (BMI), waist to hip ratio, fasting plasma glucose, insulin, and lipid, and plasma glucose and insulin responses to the glucose load were relatively similar in subjects with and without the mutation in CHD and normal groups. The degree of insulin sensitivity, ie, the steady-state plasma glucose concentration, was not significantly different between subjects with and without the mutation in the CHD group (11.3 +/- 1.2, n = 11 v 11.9 +/- 0.6 mmol/L, n = 47, P = NS) and control group (8.4 +/- 0.7, n = 30 v 8.2 +/- 0.4 mmol/L, n = 91, P = NS). We conclude that Trp64Arg polymorphism of the beta3-adrenergic receptor gene does not likely play a major role in the development of CHD in the Chinese population. In addition, it appears to have no association with the insulin resistance syndrome in either CHD or non-CHD subjects.

Troglitazone has no effect on red cell mass or other erythropoietic parameters

OBJECTIVE

Troglitazone is a new anti-diabetic agent for the treatment of type 2 diabetes. In placebo-controlled trials troglitazone improves glycaemic control, reduces hyperinsulinaemia and has beneficial effects on blood lipids. However, minor, reversible reductions in erythrocyte count, haemoglobin and haematocrit with no associated clinical symptoms have been observed in some troglitazone-treated patients. The primary objective of the present study was to determine if these changes could be explained by a decrease in red cell mass or change in plasma volume.

METHODS

Twenty-four healthy males were randomized in a double-blind manner to troglitazone (200 or 600 mg per day) or placebo for 6 weeks. Blood samples for the measurement of red cell mass and plasma volume were obtained in the 2 weeks prior to treatment and after 6 weeks of treatment. Reticulocyte and erythrocyte counts, haemoglobin and haematocrit were also measured.

RESULTS

At the end of the treatment period there were no statistically significant changes in red cell mass. Similarly there were no changes in reticulocyte count, erythropoietin or soluble transferrin receptors. These data indicate that troglitazone does not affect erythropoiesis. In addition, troglitazone was not associated with increased red blood cell destruction or haemolysis. There was a trend towards increased plasma volume in the troglitazone groups: increases of 2.5 ml x kg(-1) (5.7% increase) in the troglitazone 200 mg group and 3.4 ml x kg(-1) (7.8% increase) in the troglitazone 600 mg group were observed compared with placebo.

CONCLUSION

These data suggest that dilutional effects related to a modest increase in plasma volume may explain the haematological changes seen in other clinical trials with high doses of troglitazone, although this study has shown that the changes in plasma volume are not statistically significant.

A rapid method for exploring the protein structure universe

We have developed an automatic protein fingerprinting method for the evaluation of protein structural similarities based on secondary structure element compositions, spatial arrangements, lengths, and topologies. This method can rapidly identify proteins sharing structural homologies as we demonstrate with five test cases: the globins, the mammalian trypsinlike serine proteases, the immunoglobulins, the cupredoxins, and the actinlike ATPase domain-containing proteins. Principal components analysis of the similarity distance matrix calculated from an all-by-all comparison of 1,031 unique chains in the Protein Data Bank has produced a distribution of structures within a high-dimensional structural space. Fifty percent of the variance observed for this distribution is bounded by six axes, two of which encode structural variability within two large families, the immunoglobulins and the trypsinlike serine proteases. Many aspects of the spatial distribution remain stable upon reduction of the database to 140 proteins with minimal family overlap. The axes correlated with specific structural families are no longer observed. A clear hierarchy of organization is seen in the arrangement of protein structures in the universe. At the highest level, protein structures populate regions corresponding to the all-alpha, all-beta, and alpha/beta superfamilies. Large protein families are arranged along family-specific axes, forming local densely populated regions within the space. The lowest level of organization is intrafamilial; homologous structures are ordered by variations in peripheral secondary structure elements or by conformational shifts in the tertiary structure.

Antimutagens in food plants eaten by Polynesians: micronutrients, phytochemicals and protection against bacterial mutagenicity of the heterocyclic amine 2-amino-3-methylimidazo[4,5-f]quinoline

We have previously suggested that differences in cancer incidence between Polynesians (including Maoris and people from several Pacific islands) and Europeans in New Zealand may at least partially relate to differences in the species of food plants (fruits, vegetables and cereals) preferentially eaten by these groups. Twenty-five food plants that are typically eaten in different amounts by these two population groups were selected for detailed study. Antimutagenic properties of three extracts from each of the selected plants were investigated using a preincubation mutagenicity assay with Salmonella typhimurium strain TA1538 against the mutagenicity of the heterocyclic amine 2-amino-3-methylimidazo[4,5-f]quinoline (IQ). The data revealed strong antimutagenic properties in several of the food plants commonly eaten by Polynesians, especially rice, watercress, pawpaw, taro leaves, green banana and mango. Using the New Zealand food database, a number of nutrients and micronutrients with antimutagenic and anticarcinogenic potential were identified from the selected food plants. Some of these were tested for antimutagenic potential in parallel experiments to those done with the food plant extracts. Although some of these micronutrients are antimutagens against IQ, their concentrations in the food plants failed to explain the protection against mutagenicity found in the experiments with extracts of the food plants. Thus, other types of chemical, not identified in the database, must be leading to antimutagenesis. Possible active molecules include chlorophylls, carotenoids, flavonoids and coumarins, many of which are also known to be anticarcinogens. If human cancer data are to be interpreted in terms of cancer protection, these components need urgently to be quantified in food plants in the New Zealand diet, especially in those food plants eaten in large amounts by Polynesians.

Necrobiosis lipoidica: only a minority of patients have diabetes mellitus

Although it is commonly accepted that necrobiosis lipoidica (NL) is associated with diabetes mellitus (DM), there is some controversy regarding the degree of this association. In a retrospective review of 65 patients with NL attending our dermatology out-patient clinics we found that just seven (11%) were known to have DM at the time of presentation. Seven further patients (11%) were diagnosed as having impaired glucose tolerance/DM at presentation and over a 15-year follow-up period. Thus, only a minority of our patients with NL had DM.

Troglitazone increases the resistance of low density lipoprotein to oxidation in healthy volunteers

The oxidative modification of low density lipoprotein is of importance in atherogenesis. Antioxidant supplementation has been shown, in published work, to increase low density lipoprotein resistance to oxidation in both healthy subjects and diabetic subjects; in animal studies a contemporary reduction in atherogenesis has been demonstrated. Troglitazone is a novel oral antidiabetic drug which has similarities in structure with vitamin E. The present study assessed the effect of troglitazone 400 mg twice daily for 2 weeks on the resistance of low density lipoprotein to oxidation in healthy male subjects. Ten subjects received troglitazone and ten received placebo in a randomised, placebo-controlled, parallel-group design. The lag phase (a measure of the resistance of low density lipoprotein to oxidation) was determined by measurement of fluorescence development during copper-catalysed oxidative modification of low density lipoprotein. The lag phase was increased by 27 % (p < 0.001) at week 1 and by 24% (p < 0.001) at week 2 in the troglitazone treated group compared with the placebo group. A number of variables known to influence the resistance of low density lipoprotein to oxidation were measured. They included macronutrient consumption, plasma and lipoprotein lipid profile, alpha-tocopherol, beta-carotene levels in low density lipoprotein, low density lipoprotein particle size, mono and polyunsaturated fatty acid content of low density lipoprotein and pre-formed low density lipoprotein hydroperoxide levels in low density lipoprotein. Troglitazone was associated with a significant reduction in the amount of pre-formed low density lipoprotein lipid hydroperoxides. At weeks 1 and 2, the low density lipoprotein hydroperoxide content was 17% (p < 0.05) and 18% (p < 0.05) lower in the troglitazone group compared to placebo, respectively. In summary the increase in lag phase duration in the troglitazone group appeared to be due to the compound's activity as an antioxidant and to its ability to reduce the amount of preformed low density lipoprotein lipid hydroperoxides. This antioxidant activity could provide considerable benefit to diabetic patients where atherosclerosis accounts for the majority of total mortality.

Effect of the non peptide angiotensin II antagonist, GR117289C on the vasoconstrictor actions of angiotensin II in the human forearm

AIMS

GR117289C is a non peptide, selective angiotensin (AT1) receptor antagonist. The purpose of this study was to determine whether this agent, given orally, could attenuate the vasoconstrictor effects of angiotensin II(AII) infused locally into the forearm circulation in man.

METHODS

Eight healthy male subjects were studied on four occasions in a randomized, double-blind, placebo controlled, crossover study. Five hours (approximate time of peak dynamic effect) following dosing with GR117289C (300 mg, 100 mg, 10 mg or placebo), A II was infused in incremental doses (0, 0.1, 0.4, 1.6, 6.2, 25 and 100 pmol min-1) into the left brachial artery, each for 10 min. Forearm blood flow was measured using venous occlusion plethysmography.

RESULTS

GR117289C inhibits the vasoconstrictor effects of A II in a dose dependent manner. The active treatment: placebo ratios of forearm blood flow in the infused arm during the highest dose of AII (100 pmol min-1) were: GR117289C 10 mg, 1.12 (95% C.I. 0.81-1.55; P = 0.478), 100 mg, 1.43 (95% C.I. 1.01-2.01; P = 0.042) and 300 mg, 1.62 (95% C.I. 1.17-2.24; P = 0.006). There was no significant difference in blood pressure between each of the treatment groups and placebo.

CONCLUSIONS

GR117289C is a pharmacologically active, oral A II antagonist in healthy men.

Three keratin gene mutations account for the majority of dominant simplex epidermolysis bullosa cases within the population of Ireland

We have located three extended families in Ireland (population 3.5 million) with autosomal dominant simplex forms of Epidermolysis Bullosa (EBS). A mutation within the keratin type I (K14) gene (Met-->272-->Arg) in one family suffering from the generalized simplex (Koebner) form of the disease has been previously described (Humphries et al., Hum Mutat 2:37-42, 1993). Here we report on the identification of mutations within the remaining two families, both of whom suffer from the Weber-Cockayne form of the disease. These mutations, within the type II keratin (K5) gene, are Asn-->193-->Lys and Met-->327-->Thr. They have been shown in each case to co-segregate with the disease and are not present in the normal population. Within the three families, a total of 44 living persons with such mutations have been identified, providing a minimum prevalence estimate for the disease in the Irish population of approximately 1 in 80,000, compared to an overall estimated global incidence at birth for all forms of EB of 1 in 50,000. Therefore, these three mutations probably account for the majority of cases of EBS within this population.

Insulin resistance, glucose intolerance, and hyperinsulinemia in patients with microvascular angina

Plasma glucose and insulin responses to oral glucose and insulin-mediated glucose disposal were determined in 20 patients with microvascular angina and 20 normal volunteers who were similar in terms of age, gender distribution, and degree of obesity. Plasma glucose and insulin responses to a 75-g oral glucose challenge were significantly higher in those with microvascular angina (P < .001), as were steady-state plasma glucose concentrations after a 180-minute infusion of somatostatin, glucose, and insulin (12.2 +/- 1.0 v 7.6 +/- 0.6 mmol/L, P < .001). Since steady-state plasma insulin concentrations were similar in the two groups (627 +/- 32 v 631 +/- 29 pmol/L), these data indicate that patients with microvascular angina are insulin-resistant, glucose-intolerant, and hyperinsulinemic compared with a matched group of normal volunteers.

Putative cocaine receptor in striatum is a glycoprotein with active thiol function

Dopamine transporters of bovine and rat striata were identified by their specific [3H]cocaine binding and cocaine-sensitive [3H]dopamine [( 3H]DA) uptake. Both binding and uptake functions of bovine striatal transporters were potentiated by lectins. Concanavalin A (Con A) increased the velocity but did not change the affinity of the transporter for DA; however, it increased its affinity for cocaine without changing the number of binding sites. This suggests that the DA transporter is a glycoprotein and that Con A action on it produces conformational changes. Inorganic and organic mercury reagents inhibited both [3H]DA uptake and [3H]cocaine binding, though they were all more potent inhibitors of the former. n-Ethylmaleimide inhibited [3H]DA uptake totally but [3H]cocaine binding only partially. Also, n-pyrene maleimide had differential effects on uptake and binding, inhibiting uptake and potentiating binding. [3H]DA uptake was not affected by mercaptoethanol up to 100 mM, whereas [3H]cocaine binding was inhibited by concentrations above 10 mM. On the other hand, both uptake and binding were fairly sensitive to dimercaprol (less than 1 mM). The effects of all these sulfhydryl reagents suggest that the DA transporter has one or more thiol group(s) important for both binding and uptake activities. The Ellman reagent and dithiopyridine were effective inhibitors of uptake and binding only at fairly high concentration (greater than 10 mM). Loss of activity after treatment with the dithio reagents may be a result of reduction of a disulfide bond, which may affect the transporter conformation.

Treatment of sarcomas of the chest wall using intensive combined modality therapy

As part of two sequential protocols using intensive combined modality treatment in pediatric and adolescent sarcomas, 31 consecutive patients with primary chest wall tumors were treated between November 1977 and March 1986. This group included 13 patients with peripheral neuroepithelioma (Askin's tumor), 11 patients with Ewing's sarcoma, 3 patients with rhabdomyosarcoma, and 4 patients with undifferentiated sarcomas. Following complete work-up, 17 patients presented with localized disease and 14 patients presented with metastases. Patients received intensive combined modality treatment with combination chemotherapy (vincristine, cyclophosphamide, Adriamycin, +/- actinomycin-D and DTIC) and high-dose conventionally fractionated radiation therapy to the primary (55-60 Gy) and non-pulmonary metastases (45-50 Gy). Radiation techniques used for the primary chest wall tumor varied with the clinical presentation. Patients achieving a complete response received either low-dose fractionated TBI (1.5 Gy/0.15 Gy fx/5 weeks) or high-dose TBI (8 Gy/4 Gy fx/2 days) and an intensive cycle of chemotherapy followed by autologous bone marrow transplantation. Twenty-five of 31 patients were judged to have a complete response (including 1 patient with complete resection). With minimum follow-up of 6 months and median follow-up of 36 months from completion of treatment, 14 patients remain disease-free with 2 additional patients alive in second remission after relapse. Patients with localized disease at presentation have improved disease-free survival and overall survival compared to patients with metastases at presentation. All 17 localized patients achieved a CR and 11 are NED compared to 8 of 14 metastatic patients achieving a CR and only 3 are NED. There have been 5 loco-regional recurrences with 3 "in-field" failures and 2 failures in the regional pleura. There were no treatment-related deaths and no clinically significant cases of pneumonitis. To date, 2 patients have significant treatment related morbidity, including 1 patient with scoliosis requiring surgery and 1 patient with acute leukemia developing 42 months after the start of therapy (presently in remission). We conclude that this intensive combined modality therapy results in a high CR rate and good local control with acceptable morbidity. Patients with metastatic disease at presentation remain a therapeutic challenge.

Enhanced chemiluminescence production by phagocytosing neutrophils in psoriasis

Using serum-coated zymosan, the generation of reactive oxidants by measurement of chemiluminescence was shown to be significantly enhanced in isolated peripheral psoriatic neutrophils compared to normal controls. This response was observed irrespective of whether zymosan was opsonized with fresh autologous or normal AB serum. However, this increased activity was reduced with zymosan was opsonized with serum that was preheated at 56 degrees C for 30 min. There was no statistical correlation of chemiluminescence activity with degranulation of beta-glucuronidase in either normal or psoriatic subjects. In addition, chemiluminescence produced by normal cells was significantly increased when zymosan was opsonized with psoriatic serum. The plasma membrane-bound enzyme, NAD(P)H oxidase, which produces superoxide in response to phagocytic stimulation, was significantly increased in psoriatic neutrophils compared to normal controls. These data add further evidence for activated neutrophils in psoriasis.

5-Hydroxytryptamine-stimulated inositol phospholipid hydrolysis in the mouse cortex has pharmacological characteristics compatible with mediation via 5-HT2 receptors but this response does not reflect altered 5-HT2 function after 5,7-dihydroxytryptamine lesioning or repeated antidepressant treatments

5-Hydroxytryptamine (5-HT; 3 x 10(-8)-1 x 10(-5)M) produced a dose-dependent increase in phosphatidylinositol/polyphosphoinositide (PI) turnover in mouse cortical slices, as measured by following production of 3H-labelled inositol phosphates (IPs) in the presence of 10 mM LiCl. Analysis of individual IPs, in slices stimulated for 45 min, indicated substantial increases in inositol monophosphate (IP1; 140%) and inositol bisphosphate (IP2; 95%) contents with smaller increases in inositol trisphosphate (IP3; 51%) and inositol tetrakisphosphate (IP4; 48%) contents. The increase in IP3 level was solely in the 1,3,4-isomer. This response was inhibited by the nonselective 5-HT antagonists methysergide, metergoline, and spiperone. It was also inhibited by the selective 5-HT2 antagonists ketanserin and ritanserin but not by the 5-HT1 antagonists isapirone, (-)-propranolol, or pindolol. 5-HT-stimulated IP formation was also unaltered by atropine, prazosin, and mepyramine. Lesioning brain 5-HT neurones using 5,7-dihydroxytryptamine (5,7-DHT; 50 micrograms i.c.v.) produced a 210% (p less than 0.01) increase in the number of 5-HT2-mediated head-twitches induced by 5-methoxy-N,N-dimethyltryptamine (2 mg/kg). However, 5,7-DHT lesioning had no effect on 5-HT-stimulated PI turnover in these mice. Similarly, an electroconvulsive shock (90 V, 1 s) given five times over a 10-day period caused an 85% (p less than 0.01) increase in head-twitch responses but no change in 5-HT-stimulated PI turnover. Decreasing 5-HT2 function by twice-a-day injection of 5 mg/kg of zimeldine or desipramine (DMI) produced 50% (p less than 0.01) and 56% (p less than 0.01), respectively, reductions in head-twitch behaviour.(ABSTRACT TRUNCATED AT 250 WORDS)