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Biomedical subjects

John Strang

Publications and source records attributed to John Strang.

At least 19 recordsLinked to original sources
PubMed2005

Bouquet brachytherapy: feasibility and optimization of conically spaced implants.

PURPOSE: To examine the dosimetric feasibility of a conical implantation approach to robotic-assisted prostate brachytherapy. METHODS AND MATERIALS: An in-house inverse planning software based on the genetic algorithm (GA) was used to optimize the needle angulations and the seed positions along needles that form one or two bouquets. Volume data from 20 prostate seed implant patients (six 125I and 14 103Pd) previously treated using the conventional rectilinear template approach were used. The dosimetry outcomes of the optimized treatment plan in the conical approach were compared with those from the original treatment plans based on the conventional rectilinear template approach. RESULTS: When seed spacing is restricted to nominal 1 cm center-to-center spacing, dosimetry results in the conical approach suffer from a higher urethra dose and higher dose heterogeneity compared with the original rectilinear template plans. When the seed loading patterns are optimized as part of inverse planning, the resulting dosimetry plans exhibit adequate dose coverage and uniformity through the target volume, as well as satisfactory sparing of the urethra and rectum. CONCLUSIONS: Conically spaced implantation for prostate brachytherapy with 125I and 103Pd seeds is feasible in terms of dosimetry outcomes. Techniques for optimized inverse planning for this approach have been developed.

Brachytherapy↗
PubMed2005

Age of first use and ongoing patterns of legal and illegal drug use in a sample of young Londoners.

The significance of ages of first use of cigarettes, alcohol, cannabis, and stimulant drugs were investigated in a sample of young drug users entering an intervention study in London. Age of first cigarette smoking emerges as a robust predictor of age of first cannabis use, and age of first cannabis use in turn is predictive of age of first stimulant use, among those using both drugs. In this sample, ages of first use of cigarettes, alcohol, and cannabis are not predictive of whether stimulant drugs are used. In a series of regression models that take account of the influence of other factors, age of first use is found to have no relationship to levels of ongoing consumption of cigarettes, alcohol, and cannabis.

Adolescent↗
PubMed2005

Deterioration over time in effect of Motivational Interviewing in reducing drug consumption and related risk among young people.

AIM: To test whether beneficial effects of a single session of Motivational Interviewing (MI) on alcohol, tobacco and illicit drug use apparent after 3 months were maintained until 12 months. DESIGN: Cluster randomized trial, allocating 200 young people in the natural groups in which they were recruited to either MI (n = 105) or to an assessment-only control condition (n = 95). SETTING: Ten further education colleges across inner London. PARTICIPANTS: Two hundred young people who were current users of illegal drugs (age range 16-20 years) with whom contact was established through peers trained for the project. INTERVENTION: The intervention was adapted from MI in the form of a topic-based 1-hour single-session discussion. MEASUREMENTS: Changes in cigarette, alcohol, cannabis and other drug use and perceptions of risk and harm between the time of recruitment and follow-up interviews after 3 and 12 months. FINDINGS: A satisfactory follow-up rate (81%) was achieved. After 12 months, 3-month differences between MI and assessment-only groups have disappeared almost entirely. Unexpected improvements by the assessment-only control group on a number of outcomes suggest the possibility of reactivity to the research assessment at 3-month follow-up. CONCLUSION: In the terms of the original experiment, there is little evidence of enduring intervention effectiveness shown by between-group differences after 12 months. Deterioration of effect is the most probable explanation, although reactivity to 3-month assessment, a late Hawthorne effect, cannot be ruled out.

Adolescent↗
PubMed2005

The prescribing of methadone and other opioids to addicts: national survey of GPs in England and Wales.

BACKGROUND: GPs occupy a pivotal position in relation to providing services to opiate misusers in the UK, and this is now cited to support initiatives in other countries. AIMS: To investigate GP involvement in the management of opiate misusers; and to examine the nature of this prescribing of methadone and other opioids. DESIGN: GP data collected via self-completion postal questionnaire from a 10% random sample of the 30 000 GPs across England and Wales. Patient prescription data obtained on opiate misusers treated during the preceding 4 weeks. SETTING: Primary healthcare practice in England and Wales in mid-2001. METHOD: A questionnaire was mailed to a random 10% sample of GPs stratified by number of partners in the practice, with three follow-up mailshots. Data on drugs prescribed by these practitioners were also studied, including drug prescribed, form, dose and dispensing arrangements. RESULTS: The response rate was 66%. Opiate misusers had been seen by 51% of GPs in the preceding 4 weeks (mean of 4.1 such patients), of whom 50% had prescribed opiate-substitution drugs. This provided a study sample of 1482 opiate misusers to whom GPs were prescribing methadone (86.7%), dihydrocodeine (8.5%) or buprenorphine (4.4%). Of 1292 methadone prescriptions, mean daily dose was 36.9 mg - 47.9% being for 30 mg or less. Daily interval dispensing was stipulated by 44.6%, while 42.9% permitted weekly take-away supply. CONCLUSIONS: In 2001 nearly three times as many GPs were seeing opiate misusers than was the case in 1985. Half were prescribing substitute-opiate drugs such as methadone (to an estimated 30 000 patients). However, there are grounds for concern about the quality of this prescribing. Most doses were too low to constitute optimal methadone maintenance; widespread disregard of the availability of supervised or interval dispensing increases the risks of diversion to the blackmarket and deaths from methadone overdose. Increased quantity of care has been achieved. Increased quality is now required.

Analgesics, Opioid↗
PubMed2004

Changes in route of drug administration among continuing heroin users: outcomes 1 year after intake to treatment.

This study investigates the type and extent of changes in route of drug administration among heroin users after treatment: whether injectors move to other routes of use; whether changes in route for one drug influence routes used for other drugs; and associations between changes in route of administration and other substance use outcomes. The sample comprised 641 heroin users recruited to 54 UK treatment programmes. At intake, the main routes of heroin use were injecting (61%) and "chasing the dragon" (37%). After 1 year, 81% of those using heroin took it by the same route as at intake, while 19% reported a change, with 14% switching from injecting to chasing. Changes from injecting to chasing were associated with improvements in other substance use behaviours. Changes in route represent an important aspect of drug-taking behaviours. Interventions to prevent the change to injecting should be developed and offered to noninjectors. "Reverse transitions" (from injecting to chasing) may represent a useful intermediate treatment goal for drug injectors who cannot achieve abstinence.

Administration, Inhalation↗
PubMed2004

Can the practitioner correctly predict outcome in motivational interviewing?

We have examined whether practitioner ratings (immediately post-intervention) or other recorded characteristics of a single-session 1-hour motivational intervention were predictive of 3-month cannabis use outcome. In the context of a cluster randomized trial involving 200 non help-seeking illegal drug users (age range 16-20), 105 were randomized to the intervention, of whom 97 (92%) were interviewed for followup at 3 months, 96 of whom were current cannabis users at study entry. Six intervention characteristics and seven practitioner ratings as well as patterns of self-motivational statements were investigated in relation to substantial change in use, (which was defined as cessation or reduction by more than 50%). Both practitioner ratings post-session, and also the subject's own elicited self-motivational statements, were found to be predictive of outcome 3 months later. The strongest predictor of substantial change, however, was simply whether change had been discussed during the session. On the basis of the above findings, it does indeed appear possible for outcome to be predicted by the motivational interviewing practitioner immediately following delivery of the intervention, on the basis of simple observations and ratings. This area warrants more specific study.

Adolescent↗
PubMed2004

Engaging the reluctant GP in care of the opiate misuser: Pilot study of change-orientated reflective listening (CORL).

BACKGROUND: The GP is central to plans for improved general health care and increased availability and delivery of addiction treatment to drug misusers in the UK. Attention to the actual quality of overall primary care, rather than just the treatment of dependence, has, however, been limited. OBJECTIVES: The purpose of this study was to test the feasibility of delivery and potential value of a brief motivational enhancement intervention targeting the quality of primary care given to opiate misusers by GPs. METHOD: This study had an observational 'before and after' design with follow-up assessment after 2-3 months. The target population was all GPs in two Primary Care Groups who had neither attended training events nor were involved in the treatment of drug dependence (n = 66), who were then approached via a telephone-administered change-orientated reflective listening intervention, based on principles of motivational interviewing, with informational adjunct. Outcome measures for the study sample (n = 29) were overall therapeutic commitment and motivation to follow up and actual clinical activity and willingness to deliver specified general health care interventions for drug misusers. RESULTS: Across the study sample, therapeutic commitment improved over time, whilst motivation did not. Change among individual practitioners in receipt of the intervention was observed in both positive and negative directions, and in four of the positive changers, this was judged attributable to the intervention. Positive changes were more than twice as frequent as negative changes. CONCLUSIONS: The direction and extent of change detected were encouraging. Further initiatives are needed to influence practitioner motivation, based on improved understanding of GPs' views on the delivery of primary care for drug misusers.

Adult↗
PubMed2004

The efficacy of single-session motivational interviewing in reducing drug consumption and perceptions of drug-related risk and harm among young people: results from a multi-site cluster randomized trial.

AIM: To test whether a single session of motivational interviewing (discussing alcohol, tobacco and illicit drug use) would lead successfully to reduction in use of these drugs or in perceptions of drug-related risk and harm among young people. DESIGN: Cluster randomized trial, allocating 200 young people in the natural groups in which they were recruited to either motivational interviewing (n=105) or non-intervention education-as-usual control condition (n=95). SETTING: Ten further education colleges across inner London. PARTICIPANTS: Two hundred young people (age range 16-20 years) currently using illegal drugs, with whom contact was established through peers trained for the project. INTERVENTION: The intervention was adapted from the literature on motivational interviewing in the form of a 1-hour single-session face-to-face interview structured by a series of topics. MEASUREMENTS: Changes in self-reported cigarette, alcohol, cannabis and other drug use and in a range of drug-specific perceptions and other indicators of risk and harm. Measurement at recruitment and follow-up interview 3 months later. FINDINGS: A good follow-up rate (89.5%; 179 of 200) was achieved. In comparison to the control group, those randomized to motivational interviewing reduced their of use of cigarettes, alcohol and cannabis, mainly through moderation of ongoing drug use rather than cessation. Effect sizes were 0.37 (0.15-0.6), 0.34 (0.09-0.59) and 0.75 (0.45-1.0) for reductions in the use of cigarettes, alcohol and cannabis, respectively. For both alcohol and cannabis, the effect was greater among heavier users of these drugs and among heavier cigarette smokers. The reduced cannabis use effect was also greater among youth usually considered vulnerable or high-risk according to other criteria. Change was also evident in various indicators of risk and harm, but not as widely as the changes in drug consumption. CONCLUSIONS: This study provides the first substantial evidence of non-treatment benefit to be derived among young people involved in illegal drug use in receipt of motivational interviewing. The targeting of multiple drug use in a generic fashion among young people has also been supported.

Adolescent↗
PubMed2004

Relationship between prescribing and risk of opiate overdose among drug users in and out of maintenance treatment.

Opiate users (n = 135) from southern England, Glasgow and Edinburgh were interviewed about opiate overdose (lifetime). Fifty-six percent had overdosed. The majority (66%) reported mixing opiates with at least one other drug (mainly alcohol and/or benzodiazepines) at their last overdose. Patients identified misjudgements of purity, mixing drugs and misjudgements of tolerance as causes of overdose. The sample was divided into groups: (1) 'no prescription', (2) prescribed 'diazepam only', (3) prescribed 'methadone only' and (4) prescribed 'methadone + diazepam'. The 'methadone + diazepam' group reported more lifetime and deliberate overdoses, the 'methadone only' group were more likely to have used several drugs at the time of their last overdose and the 'no prescription' group to have used only heroin. Drug users' overdose risk may vary as a result of their prescribed and non-prescribed drug use. Interventions should be developed and tailored according to clients' needs and current use patterns.

Adult↗
PubMed2004

Does anyone care about names? How attendees at substance misuse services like to be addressed by health professionals.

OBJECTIVE: To determine the preference of substance misusers for the terms 'patient', 'client' and 'service user' in the context of their contact with health professionals, if they consider substance misuse problems to exist appropriately under the category of mental health problems and if they consider themselves to have mental health problems. METHODS: A self-completion questionnaire was administered to 150 National Health Service and private in- and outpatients with alcohol, drug and smoking problems. RESULTS: The majority (54%) preferred the term 'patient', felt substance misuse problems was a category of mental health problems (59%), even though the majority (62%) did not consider themselves to have a mental health problem. Broadly similar preferences were found for those attending drug services and alcohol services whilst those attending the smoking cessation service were less likely to consider it an appropriate location or description. DISCUSSION: The majority of substance misusers preferred to be called 'patients'. The location of substance misuse services within mental health provision was widely tolerated.

Adult↗
PubMed2003

Automatic localization of implanted seeds from post-implant CT images.

An automatic localization method of implanted seeds from a series of post-implant computed tomography (CT) images is described in this paper. Post-implant CT studies were obtained for patients who underwent prostate brachytherapy. Bright areas were segmented using binary thresholding in each CT slice, and geometrical information on these areas was collected. Large areas (possibly containing two connected seeds) were split into smaller ones by geometry-based filtering in each slice. The area connectivity along the longitudinal direction was analysed using a geometry-based connection search algorithm executed on every area slice by slice, so that the connected areas were combined into one object. The weighted centroid of each object was taken as the seed position. This method was tested on a seed-containing prostate phantom as well as using CT studies from patients. Statistical analysis demonstrates that it can achieve above 99% detection rate with reliable localization accuracy and high speed. It is reliable and convenient for localizing implanted seeds on CT and can be used to assist post-implant dosimetry for prostate brachytherapy.

Algorithms↗
PubMed2003

Getting by with a little help from your friends: the impact of peer networks on criminality in a cohort of treatment-seeking drug users.

This study investigates the links between social networks of drug users and criminal activity. Opiate misusers (n=128) receiving in-patient treatment were interviewed about substance use, social networks, and crime in the month before treatment. Almost 60% of participants reported an average of more than 70 crimes each. Less than one-fifth of the subjects spent no time with other users, while just over half spent either "quite a lot" or "a lot" of time with drug users. Time with users increased the risk of crime. Spending no time with users provided a protective effect. Time with criminally involved drug users was associated with greater levels of crime. Social networks represent an important marker for integration in criminal networks in treatment-seeking drug users and a long-term barrier to rehabilitation.

Adult↗
PubMed2003

Measuring therapeutic attitude among drug workers.

A reluctance of nonspecialists to work with drug and alcohol misusers have focused upon belief-based systems, including therapeutic commitment (TC) and situation-specific constraints. This paper describes the development and assessment of a theoretical model for nonspecialist drug workers, characterised as a synthesis of attitudinal and constraints explanations. A cohort of 189 nonspecialist drug workers completed self-report measures of overall TC and situational constraints scales. Predictive analysis of associations between TC, role security (RS), role requirements, and situational constraints was performed to explore direct and indirect effects. Such assessment allowed for the identification of a predictive process by which TC may be established, manipulated, and maintained. Levels of TC were found to be explained by the direct effects of self-esteem (SE), situational constraints, role support, and RS. Role support and situational constraints were also found to have indirect effects. Experience with working with drug users and education on drug-related issues were found to have predominantly indirect effects on TC via situational constraints and RS. Findings show the synthesised model to be partially supported. Implications for the development of a process-driven theoretical understanding of TC and situational constraints are discussed, and applied recommendations for training intervention are presented.

Adult↗
PubMed2003

Development of a structured generic drug intervention model for public health purposes: a brief application of motivational interviewing with young people.

Brief applications of Motivational Interviewing (MI) emerged around 15 years ago to target problematic alcohol and other drug use. Interventions which specifically target illicit drug use, young people, or which are delivered in settings other than health-care services have, however, been relatively slow to develop. The needs of young people for interventions distinct from those offered to adults are considered, as a precursor to an outline of the structure of a newly adapted intervention targeting drug use in general among young people. Based upon earlier topic-based approaches developed by Rollnick et al. this intervention is innovative in simultaneously targeting a range of drugs in pursuit of secondary prevention objectives, while also seeking to manifest the spirit of MI. The intervention consists of a single-session face-to-face conversation of up to 60 minutes duration. Data are presented which describe the development and conduct of this intervention during the course of an efficacy trial, with promising efficacy data themselves reported elsewhere. Observations are made on intervention delivery and consideration is given to implications for further novel targeting of young people and within the field of addiction interventions more generally. [McCambridge J, Strang J. Development of a structured generic drug intervention model for public health purposes: a brief application of motivational interviewing with young people.

Adolescent↗