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Biomedical subjects

John Strang

Publications and source records attributed to John Strang.

At least 19 recordsLinked to original sources
PubMed2006

Methodology for the Randomised Injecting Opioid Treatment Trial (RIOTT): evaluating injectable methadone and injectable heroin treatment versus optimised oral methadone treatment in the UK.

Whilst unsupervised injectable methadone and diamorphine treatment has been part of the British treatment system for decades, the numbers receiving injectable opioid treatment (IOT) has been steadily diminishing in recent years. In contrast, there has been a recent expansion of supervised injectable diamorphine programs under trial conditions in a number of European and North American cities, although the evidence regarding the safety, efficacy and cost effectiveness of this treatment approach remains equivocal. Recent British clinical guidance indicates that IOT should be a second-line treatment for those patients in high-quality oral methadone treatment who continue to regularly inject heroin, and that treatment be initiated in newly-developed supervised injecting clinics. The Randomised Injectable Opioid Treatment Trial (RIOTT) is a multisite, prospective open-label randomised controlled trial (RCT) examining the role of treatment with injected opioids (methadone and heroin) for the management of heroin dependence in patients not responding to conventional substitution treatment. Specifically, the study examines whether efforts should be made to optimise methadone treatment for such patients (e.g. regular attendance, supervised dosing, high oral doses, access to psychosocial services), or whether such patients should be treated with injected methadone or heroin. Eligible patients (in oral substitution treatment and injecting illicit heroin on a regular basis) are randomised to one of three conditions: (1) optimized oral methadone treatment (Control group); (2) injected methadone treatment; or (3) injected heroin treatment (with access to oral methadone doses). Subjects are followed up for 6-months, with between-group comparisons on an intention-to-treat basis across a range of outcome measures. The primary outcome is the proportion of patients who discontinue regular illicit heroin use (operationalised as providing >50% urine drug screens negative for markers of illicit heroin in months 4 to 6). Secondary outcomes include measures of other drug use, injecting practices, health and psychosocial functioning, criminal activity, patient satisfaction and incremental cost effectiveness. The study aims to recruit 150 subjects, with 50 patients per group, and is to be conducted in supervised injecting clinics across England.

Journal Article↗
PubMed2006

Excessive drinking and other problem behaviours among 14-16 year old schoolchildren.

The study investigates excessive drinking and associations with other problem behaviours in 2078 school students aged 14-16 years in seven London secondary schools. Using a cross-sectional design, a self-completion questionnaire assessed lifetime and recent (past month) alcohol and drug consumption, attitudes to alcohol use education, alcohol-related problems, psychological problems, educational aspirations, truancy, and delinquent behaviour. Excessive drinking was operationally defined as 10 or more units of alcohol per drinking occasion. At least one episode of excessive drinking was reported by 32% of the sample, with 10% reporting five or more episodes. Excessive drinking was positively associated with frequency of cigarette smoking, use of cannabis, positive attitudes towards illicit drugs, low educational aspirations, higher depression scores, frequent truancy, and involvement in delinquent behaviours. Excessive drinking is a problematic behaviour in its own right but it is also a marker for other problem behaviours, including illicit drug misuse and delinquency. Understanding and responding to alcohol misuse among adolescents requires attention to psychological, social and developmental factors other than alcohol consumption alone.

Adolescent↗
PubMed2006

The reliability of drug use data collected in the classroom: what is the problem, why does it matter and how should it be approached?

Difficulties in collecting reliable data on drug use in the context of an exploratory trial of a drug prevention intervention have led to a consideration of the wider issues of the reliability of routinely collected data. A problem is identified, and although its magnitude cannot currently be described, its nature and possible significance are considered. In this methodological discussion, significant practical and ethical issues are explored, including some of the complexities inherent in conducting research on drug use in schools, along with the need to develop improved methods of study which address the specific challenges posed by the school environment. Implications for the development of effective drug prevention interventions in schools are also examined.

Data Collection↗
PubMed2006

Heroin and methadone prescriptions from a London drug clinic over the first 15 years of operation (1968-1983): old records examined.

We charted changes in the prescriptions issued to opiate addicts in treatment at a London clinic over the first 15 years of operation of one of the new National Health Service (NHS) drug clinics established in 1968. Having located the original handwritten ledger records of prescriptions issued by the drug addict treatment clinic, an SPSS data file was created of the prescriptions given to each of the clinic patients each month over the period 1968-1983 to permit examination of changes over this 15-year period in the drugs prescribed (e.g., heroin, methadone), the form (e.g., injectable or oral), the daily doses, and the extent of multiple items for single patients (e.g., both injectable ampule and oral forms). For each month, a list was available of all current patients detailing which drug(s) they had received during that month, in what form(s) and what dose(s). These items were the basic units of study. We report changes over the 15-year period for which the data were available. For the first 5 years, more than half of the prescriptions were for heroin (diamorphine hydrochloride), with the remainder of the prescriptions mostly comprising oral methadone. After 1973, methadone ampules for injection were increasingly commonly prescribed and thereafter remained at about a quarter of the prescriptions for the remaining 10 years for which data are available, whereas heroin prescriptions declined over the mid-1970s to only 20%. From 1973 onward, oral methadone was increasingly prescribed, rising from approximately one third of prescriptions in the early 1970s to more than two thirds by the early 1980s. Individual patients often received more than one drug or form of drug: From 1969 onward, oral methadone was commonly prescribed as a supplement to heroin prescriptions. This same practice was widespread with prescriptions for methadone ampules prescribed as a supplement to heroin prescriptions. Daily doses of heroin were at a mean of from 160 to 540 mg, in contrast with means of 20 to 40 mg and 25 to 50 mg daily for the injectable methadone ampules and the oral methadone solution, respectively. Major changes occurred in the prescribing practices of this London drug clinic over the first 15 years of operation of the new NHS clinics. However, these changes did not occur overnight and can be seen to have been gradual evolutions of practice with the preservation of heroin prescription through the first 5 years and the subsequent move to increased prescribing of injectable methadone, with both these practices being overtaken by the subsequent increased prominence of oral methadone syrup as the main drug prescribed. Reference to the original records reveals a more interesting picture than might be evident from the potentially selective recall of contemporary or historical commentators.

Drug Prescriptions↗
PubMed2006

Interactions on mixing diazepam with methadone or buprenorphine in maintenance patients.

Benzodiazepine use by patients in methadone and buprenorphine substitution treatment is common, despite safety concerns regarding these drug interactions. The relative safety of diazepam use by methadone- or buprenorphine-treated patients has not been systematically examined. This study aimed to examine the effect of single diazepam doses, within normal therapeutic range (doses: 0, 10, and 20 mg), upon physiological, subjective, and performance measures in stable methadone and buprenorphine-treated patients. In a double-blind, randomized crossover design, methadone- or buprenorphine-treated patients were administered their normal opioid dose and either placebo, 10-, or 20-mg diazepam, in balanced order over 3 sessions. Eight methadone- and 8 buprenorphine-prescribed patients with no concurrent benzodiazepine dependence or significant comorbidity were recruited from an outpatient addiction clinic in London. Measures were taken at baseline and for 6 hours after dosing, and included physiological responses (pulse rate, blood pressure, pupil size, respiratory rate, and peripheral pO2), subjective drug effects (Addiction Research Center Inventory subscales, visual analog scales of strength of drug effect, drug-liking, and sedation), and performance measures (simple reaction time, cancellation task, digit symbol substitution task, and balance). The 10- and 20-mg diazepam doses resulted in comparable subjective experiences of greater sedation and strength of drug effects in both patient groups, and had minimal impact on physiological parameters. However, diazepam had greater peak effects on performance measures (simple reaction time, digit symbol substitution task, and cancellation time) in methadone-treated than in buprenorphine-treated patients. Diazepam may significantly alter the response to opioid substitution treatment with methadone or buprenorphine.

Adolescent↗
PubMed2006

Persistence of drug use during imprisonment: relationship of drug type, recency of use and severity of dependence to use of heroin, cocaine and amphetamine in prison.

AIM: To investigate the persistence of use of heroin, cocaine and amphetamine drugs during imprisonment, and to identify factors associated with increased levels of persistence. DESIGN: The use of heroin, cocaine and amphetamine by current prison inmates has been examined and, in particular, the relationship between drug use within prison and the type of drug used prior to imprisonment, recency of use and severity of dependence. SETTING AND PARTICIPANTS: A randomly selected sample of 1009 adult male prisoners in 13 prisons in England and Wales during 1994/95; structured confidential interviews conducted by independent research staff. Enquiry about prior use of heroin, cocaine or amphetamine focused on three time-periods (ever, last year and last month pre-prison) and the use of these drugs during the first month of imprisonment. FINDINGS: A total of 557 (55%) of the 1009 prisoners had used previously one of the three drugs selected for study: 58% had used heroin, 69% cocaine and 75% amphetamine. More than half (59%; 327/557) had used these drugs in the month before the current imprisonment. Drug use in prisons was most likely to occur among those who had used in the month prior to imprisonment. The persistence of heroin use in prison occurred more frequently (70%) than use of cocaine (20%) or amphetamine (15%). Of those using heroin pre-imprisonment, 67% considered they were dependent, compared to 15% and 22%, respectively, for cocaine and amphetamine users. CONCLUSIONS: Changes in the drug-taking behaviour of drug users after imprisonment vary according to the type of drug being taken. Prisoners were much more likely to continue to use heroin than either cocaine or amphetamines while in prison. Heroin was most likely to be used by those who had been using heroin during the immediate pre-imprisonment period, and particularly by the two-thirds of heroin users who considered themselves dependent. In view of the high prevalence of prior use of these drugs by individuals currently imprisoned, continuing attention is required to study of their behaviour and of the impact of interventions that may be introduced during or following their incarceration.

Adolescent↗
PubMed2006

Hybrid dosimetry: feasibility of mixing angulated and parallel needles in planning prostate brachytherapy.

Pubic arch interference (PAI) often caused inadequate prostate coverage during transperineal brachytherapy using all parallel needles. In this paper, a hybrid implantation approach is presented in which additional angulated needles can be used to avoid PAI. This approach can be applied in prostate brachytherapy using a robotic assisted device. To examine the feasibility of this approach, volume data from three prostate seed implant patients were selected, which represent small, medium, and large prostates. As the blocking area was artificially increased simulating pubic arch overlap, the dosimetry outcomes and ratio of number of angulated needles to the total number of needles were analyzed. The hybrid dosimetry broke down when blocking is over 42%. As the percent of blocking increased, the ratio of the number of angulated needles to the total number of needles increased, while the dosimetry outcomes only had a slight trend of worsening. When close to the breakdown point, the dosimetry outcomes worsen drastically. Therefore, for moderate PAI the hybrid dosimetry is feasible.

Brachytherapy↗
PubMed2006

Vivo motion and force measurement of surgical needle intervention during prostate brachytherapy.

In this paper, we present needle insertion forces and motion trajectories measured during actual brachytherapy needle insertion while implanting radioactive seeds in the prostate glands of 20 different patients. The needle motion was captured using ultrasound images and a 6 degree-of-freedom electromagnetic-based position sensor. Needle velocity was computed from the position information and the corresponding time stamps. From in vivo data we found the maximum needle insertion forces to be about 15.6 and 8.9 N for 17 gauge (1.47 mm) and 18 gauge (1.27 mm) needles, respectively. Part of this difference in insertion forces is due to the needle size difference (17G and 18G) and the other part is due to the difference in tissue properties that are specific to the individual patient. Some transverse forces were observed, which are attributed to several factors such as tissue heterogeneity, organ movement, human factors in surgery, and the interaction between the template and the needle. However, theses insertion forces are significantly responsible for needle deviation from the desired trajectory and target movement. Therefore, a proper selection of needle and modulated velocity (translational and rotational) may reduce the tissue deformation and target movement by reducing insertion forces and thereby improve the seed delivery accuracy. The knowledge gleaned from this study promises to be useful for not only designing mechanical/robotic systems but also developing a predictive deformation model of the prostate and real-time adaptive controlling of the needle.

Brachytherapy↗
PubMed2006

Feasibility and acceptability of an intranasal diamorphine spray as an alternative to injectable diamorphine for maintenance treatment.

An intranasal (IN) diamorphine spray was investigated as a possible alternative to injectable diamorphine for maintenance treatment. Plasma morphine and 6-monoacetylmorphine (6MAM) concentrations and pharmacodynamic responses were measured for 4 h following intravenous (IV) and IN administration of 40 mg diamorphine in 4 patients prescribed injectable diamorphine. The two routes were primarily differentiated by the significantly greater speed and magnitude of peak plasma morphine and 6MAM concentrations for IV versus IN diamorphine. Beyond this initial peak, mean ratings suggested that withdrawal suppression and positive effects were at least as strong for IN compared to IV administration. All subjects gave favourable appraisals of the IN diamorphine spray, citing advantages including ease of use, the avoidance of needle hazards, and reduced stigma. IN administration may be an alternative or supplementary form of diamorphine maintenance and deserves serious further investigation.

Administration, Intranasal↗
PubMed2005

The effectiveness of motivational interviewing delivered by youth workers in reducing drinking, cigarette and cannabis smoking among young people: quasi-experimental pilot study.

AIM: To test whether a single session of Motivational Interviewing (MI) focussing on drinking alcohol, and cigarette and cannabis smoking, would successfully lead to reductions in use or problems. METHODS: Naturalistic quasi-experimental study, in 162 young people (mean age 17 years) who were daily cigarette smokers, weekly drinkers or weekly cannabis smokers, comparing 59 receiving MI with 103 non-intervention assessment-only controls. MI was delivered in a single session by youth workers or by the first author. Assessment was made of changes in self-reported cigarette, alcohol, cannabis use and related indicators of risk and problems between recruitment and after 3 months by self-completion questionnaire. RESULTS: 87% of subjects (141 of 162) were followed up. The most substantial evidence of benefit was achieved in relation to alcohol consumption, with those receiving MI drinking on average two days per month less than controls after 3 months. Weaker evidences of impact on cigarette smoking, and no evidence of impact on cannabis use, were obtained. CONCLUSIONS: Evidence of effectiveness for the delivery of MI by youth workers in routine conditions has been identified. However, the extent of benefit is much more modest than previously identified in efficacy studies.

Adolescent↗
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

Are cannabis users exposed to other drug use opportunities? Investigation of high-risk drug exposure opportunities among young cannabis users in London.

In a study of young cannabis users attending further education colleges across London which specifically excluded young heroin users or injecting drug users, 35% were found to have been offered heroin, 36% had been present during heroin smoking, and 12% present at injecting. Factors associated with these exposure opportunities were investigated. The proportion of friends who use drugs other than cannabis was also considered, both as an indicator of risk in its own right and as a possible mechanism for high-risk drug exposure opportunities involving heroin and/or injecting. Alcohol variables and interactional problems perceived by the study subjects to be caused by their own drug use were found to be predictive of the involvement of friends in drug use other than cannabis and of exposure to heroin and injecting drug use. Non-cannabis illicit drug use among friends was also found to be associated with offers of heroin and with having been present during injecting drug use by others. Interpretations of these data are considered and the need for more detailed study with an area of increasing public policy significance is discussed.

Adolescent↗
PubMed2005

Cannabis use in adolescents: the impact of risk and protective factors and social functioning.

The study uses a school-based sample to test the social and familial risk and protective factors relating to cannabis use. Based on a self-completion survey of 2078 14-16-year-olds (mean age of 15 years) attending seven standard state-run secondary schools in south London, an assessment was made of rates and risk factors for cannabis use. Twenty-four per cent of the total sample had ever used cannabis, with 15% having done so in the month prior to assessment. In addition to greater likelihood of illicit drug use, lifetime cannabis users were less likely to spend time regularly with both their mothers and fathers, but more likely to spend free time with friends who smoked, drank alcohol and used illicit drugs, and with friends involved in criminal activities. Among those who had ever used cannabis, frequency of cannabis use was predicted (using linear regression) by two onset factors (earlier initiation of drinking and cannabis use were both linked to more frequent use) and two social factors (more time spent with drug-using friends and less time spent with the mother). Overall, the study showed that early onset, itself predicted by social networks, is linked to more frequent use of cannabis and that this appears to be sustained by less time spent with parents and more with drug-using peers.

Adolescent↗
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

Dying for heroin: the increasing opioid-related mortality in the Republic of Ireland, 1980-1999.

BACKGROUND: Over the past 20 years there has been a steady rise in mortality associated with opioid misuse in several Western countries. We aimed to examine trends in opioid-related mortality over a 20-year period in the Republic of Ireland. METHODS: Retrospective analysis of deaths attributed to ICD-9 codes 304.0 (morphine-type dependence) and E850.0 (accidental poisoning by opiates and related narcotics) in the Republic of Ireland between 1980 and 1999. RESULTS: The Republic of Ireland has seen a rapid increase in the number of opioid-related deaths over the 20-year period studied, from 0.01% of total deaths in 1980 to 0.15% in 1999. This is most marked in the younger age groups where, for example, it rose to 23% of 15-19 year old male deaths for 1997. The opioid-related mortality rate in the 15-44 years age range increased by nearly 14 times between 1980-1984 and 1995-1999. Over the whole period, 87% of opioid-related deaths were amongst males. Outside Dublin there has been a considerable increase in opioid-related mortality, nearly doubling the percentage of the total from 6% in the 1980s to 11% in the 1990s. CONCLUSIONS: Opioid-related mortality is an increasing problem in the Republic of Ireland, as in other Western countries. Today, young people have a very low mortality rate, and hence this rapid increase may need specific targeted interventions. The spread of opioid-related mortality outside Dublin to rural and other urban areas will have implications for service planning and provision.

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↗