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Biomedical subjects

M Torrens

Publications and source records attributed to M Torrens.

At least 19 recordsLinked to original sources
PubMed2006

Psychiatric comorbidity in young heroin users.

In order to determine the prevalence of psychiatric comorbidity in a population of young heroin users recruited from outside of the healthcare context, a sample was assembled by targeted sampling and nomination techniques; it was comprised of regular current users of heroin aged between 18 and 30 years and resident in Barcelona, Spain. Psychiatric evaluation was done with the Psychiatric Research Interview for Substance and Mental Disorders (PRISM) semi-structured interview. Of 149 individuals evaluated, 33% were women, whose mean age was 25.1 years; 93% received a diagnosis of heroin dependence and 71% of cocaine dependence. Thirty-two percent of the subjects had never been treated for substance use. Around two-thirds (67.1%, 95% CI: 59.6-74.7%) of the sample had lifetime psychiatric comorbidity, with antisocial personality and mood disorders being the most frequent conditions (33% and 26%, respectively). Mood, anxiety and eating disorders were more common among women than men. There were no differences in ever having been in treatment for drug use according to the presence of psychiatric comorbidity, although comorbidity was lower among those currently in treatment. Young heroin users recruited on the street presented a high prevalence of psychiatric comorbidity which was unrelated to past treatment history.

Adolescent↗
PubMed2005

Three-dimensional dose verification of the clinical application of gamma knife stereotactic radiosurgery using polymer gel and MRI.

This work seeks to verify multi-shot clinical applications of stereotactic radiosurgery with a Leksell Gamma Knife model C unit employing a polymer gel-MRI based experimental procedure, which has already been shown to be capable of verifying the precision and accuracy of dose delivery in single-shot gamma knife applications. The treatment plan studied in the present work resembles a clinical treatment case of pituitary adenoma using four 8 mm and one 14 mm collimator helmet shots to deliver a prescription dose of 15 Gy to the 50% isodose line (30 Gy maximum dose). For the experimental dose verification of the treatment plan, the same criteria as those used in the clinical treatment planning evaluation were employed. These included comparison of measured and GammaPlan calculated data, in terms of percentage isodose contours on axial, coronal and sagittal planes, as well as 3D plan evaluation criteria such as dose-volume histograms for the target volume, target coverage and conformity indices. Measured percentage isodose contours compared favourably with calculated ones despite individual point fluctuations at low dose contours (e.g., 20%) mainly due to the effect of T2 measurement uncertainty on dose resolution. Dose-volume histogram data were also found in a good agreement while the experimental results for the percentage target coverage and conformity index were 94% and 1.17 relative to corresponding GammaPlan calculations of 96% and 1.12, respectively. Overall, polymer gel results verified the planned dose distribution within experimental uncertainties and uncertainty related to the digitization process of selected GammaPlan output data.

Acrylic Resins↗
PubMed2004

Repeated doses administration of MDMA in humans: pharmacological effects and pharmacokinetics.

RATIONALE: 3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") is increasingly used by young people for its euphoric and empathic effects. MDMA presents non-linear pharmacokinetics, probably by inhibition of cytochrome P450 isoform 2D6. Users are known to often take more than one dose per session. This practice could have serious implications for the toxicity of MDMA. OBJECTIVE: To evaluate the pharmacological effects and pharmacokinetics of MDMA following the administration of two repeated doses of MDMA (24 h apart). METHODS: A randomised, double-blind, cross-over, placebo controlled trial was conducted in nine healthy male subjects. Variables included physiological, psychomotor performance, subjective effects, endocrine response and pharmacokinetics. MDMA 100 mg or placebo was administered in two successive doses separated by an interval of 24 h. RESULTS: MDMA produced the prototypical effects of the drug. Following a second dose, plasma concentrations of MDMA increased (AUC 77% and Cmax 29%) in comparison with the first. The increase is greater than those expected by simple accumulation and indicates metabolic inhibition. The pharmacological effects after the second dose were slightly higher than those observed after the first in the majority of variables including blood pressure, heart rate, most subjective effects and cortisol concentrations. The effects were similar in the case of pupil diameter, esophoria and prolactin. CONCLUSIONS: Pharmacological effects after the second administration were higher than those following the first but lower than expected. A disproportionate increase in plasma concentrations in MDMA and MDA was observed most likely due to metabolic inhibition. This inhibition lasts at least 24 h. Further experiments need to be conducted to evaluate its duration.

Adult↗
PubMed2001

Differences in severity of heroin dependence by route of administration: the importance of length of heroin use.

To explore differences in the severity of heroin dependence by route of administration, we interviewed 909 heroin users in three Spanish cities. Dependence was measured with the severity dependence scale (SDS). No major differences in the severity of heroin dependence were detected among users with 5 or more years of heroin use (long-term users), but differences were found among newer users (SDS mean scores, 7.3 in heroin injectors; 7.9 in smokers and 4.6 in sniffers; P = 0.006), especially those with fewer than 3 years of use. Similar differences by route of administration were found when frequency of heroin use (days/month) was considered rather than severity of dependence. However, in the latter case major differences were also found among long-term users. These findings suggest that the route of administration probably influences the rate of progression to dependence but has little influence on the long-run level of dependence. They also help explain some aspects of the transition between routes of heroin administration, which is occurring in different areas.

Adolescent↗
PubMed2001

Psychometric properties of the Temperament and Character Inventory (TCI) questionnaire in a Spanish psychiatric population.

OBJECTIVE: The psychometric properties of the Spanish version of Cloninger's Temperament and Character Inventory (TCI) were examined in a psychiatric population. METHOD: Internal consistency, factor structure and concurrent validity were studied in a sample of 416 psychiatric patients. RESULTS: A moderate to high internal consistency for all personality dimensions was found, except for Persistence. A confirmatory factor analysis of the TCI performed at the subscale level revealed an uncertain factor structure. However, when analysed separately, both the 11 temperament subscales (plus Persistence) and the 13 character subscales shaped four and three factors, respectively, in agreement with the biosocial model of personality. Finally, concurrent validity analyses were conducted using EPQ, SPSR and SSS questionnaires showing results consistent with theory. CONCLUSION: The Spanish version of the TCI is a reliable and valid instrument, although the Persistence dimension might require further revision.

Adult↗
PubMed2001

Analytical methodology for the detection of benzodiazepine consumption in opioid-dependent subjects.

Benzodiazepines are frequently abused by heroin users, but not all compounds have shown the same abuse liability. We developed an analytical method that was able to detect various benzodiazepine compounds in a single run. Enzymatically hydrolyzed urine underwent a liquid-liquid extraction procedure with chloroform/isopropanol (9:1) at pH 8-9 followed by a solid-liquid clean-up (Bond Elut TCA C18) to obtain appropriate extracts for HPLC analysis. Mobile phase composition was optimized by means of the linear solvation energy relationship methodology based on Reichardt's normalized solvatochromic parameter (E(T)N). The method was validated for the simultaneous detection and quantitation of alprazolam, alpha-hydroxyalprazolam, oxazepam, 7-aminoflunitrazepam, flunitrazepam, nordiazepam, lorazepam, and diazepam. The prevalence of benzodiazepine consumption in 229 opioid-dependent subjects on methadone-maintenance treatment was 48%. Oxazepam and nordiazepam were the benzodiazepines most frequently recoved in urine samples. The prevalence of alprazolam use (40%) was higher than that of flunitrazepam (10%).

Adult↗
PubMed1999

Methadone treatment in Spain, 1994.

The objective of this study was to describe the methadone treatment (MT) network in Spain, and to evaluate compliance with criteria known to influence the spread of human immunodeficiency virus (HIV). During the last 3 months of 1994, a mailed questionnaire was sent to the coordinators of all methadone treatment centers in Spain. A total of 224 centers completed the questionnaire (90% response rate). The total number of patients receiving MT in the studied centers was 13,402. Their mean age was 29 years, 79% were male, and approximately 60% were HIV positive. The rate of patients in MT varied by Region (mean: 6.7 patients in MT per 10,000 inhabitants). Although the global mean of reported daily dose of methadone was 60 mg, in 44% of the centers it was lower than that. Despite the high number of centers involved with MT in Spain, the coverage by regions is unequal. Studied centers revealed only a moderate adherence to procedures considered to be effective in HIV prevention. Given the magnitude of HIV infection in Spain, there is a clear need for improvement.

Adolescent↗
PubMed1998

Plasma methadone concentrations as an indicator of opioid withdrawal symptoms and heroin use in a methadone maintenance program.

Plasma methadone concentrations and its main metabolite D,L-2-ethylidiene-1,5-dimethyl-3,5-diphenylpyrrolidine (EDDP) were determined in 93 patients under methadone maintenance treatment to assess their relationship with heroin use and opioid withdrawal symptoms. Neither plasma concentrations of methadone nor EDDP were significantly different when patients that used heroin in last 3 months were compared with those testing negative for this drug (methadone, 355 +/- 217 versus 369 +/- 216 ng/ml, t = 0.29, P = NS; EDDP, 49 +/- 28 versus 54 +/- 40 ng/ml, t = 0.51, P = NS). No correlation between opioid withdrawal scale scores and plasma concentrations of methadone (r = 0.02, P = NS) and EDDP (r = -0.14, P = NS) was found. Therapeutic drug monitoring during methadone maintenance seems to be useful for assessing compliance with treatment but not for predicting heroin use and subjective withdrawal symptoms.

Adult↗
PubMed1998

Abuse liability of flunitrazepam among methadone-maintained patients.

Abuse liability and acute subjective and psychomotor effects of flunitrazepam were assessed in ten methadone-maintained males with history of benzodiazepine and alcohol use, who voluntarily participated in a double-blind, controlled, cross-over, randomized clinical trial. There were six experimental sessions in which a single oral dose of flunitrazepam 1, 2, and 4 mg; triazolam 0.5 and 0.75 mg; and placebo was given. Evaluations included physiological measures; psychomotor performance tasks (simple reaction time, Digit Symbol Substitution Test, balance task, Maddox-wing device); and self-administered subjective effects questionnaires [Addiction Research Center Inventory (ARCI), Profile of Mood States (POMS), a series of visual analog scales (VAS)]. All drugs but flunitrazepam 1 mg caused an impairment of psychomotor tasks. Effects were more evident with the highest doses of both drugs. Only flunitrazepam 4 mg produced a significant decrease in balance time. Triazolam 0.75 mg induced increases in sedation measured by ARCI-PCAG, depression in POMS, and VAS-drowsiness scores. Flunitrazepam 4mg caused euphoria-related effects as measured by increases in ARCI-MBG and "high" scores in the VAS. Our findings of flunitrazepam-induced euphoria in methadone-maintained subjects together with epidemiological evidence of flunitrazepam abuse by opioid dependents, suggest that it may be included in the group of benzodiazepines with a relatively high abuse potential.

Adult↗
PubMed1997

Dorsal root entry zone lesion performed with Nd:YAG laser.

Thermocoagulation of the dorsal root entry zone (DREZ) is the current surgical management of deafferentation pain syndromes. It is usually performed with the assistance of specially designed lesion generators. We report a patient who underwent a DREZ lesion with a Nd:YAG laser as an alternative to standard thermocoagulation technique. A 62-year-old woman with a 5-year history of bilateral dysaesthetic (burning) type of leg pain, after a crush fracture of the fourth thoracic vertebra and complete cord transection, was managed by inducing a bilateral dorsal root entry zone lesion at T2-T5 myelotomes using a Nd:YAG laser, which was used as an alternative to the conventional electrically generated thermocoagulation. A significant reduction of deafferentation type of pain was achieved.

Female↗
PubMed1997

Use of the Nottingham Health Profile for measuring health status of patients in methadone maintenance treatment.

This study was conducted to assess changes in health-related quality of life over a 3-year follow-up period in a cohort of 135 opioid dependent patients using the Nottingham Health Profile (NHP) questionnaires. Data obtained at 12 months from 80 patients retained in the programme are presented. In summary, opioid addicts in a methadone maintenance programme for a 12-month period experienced an early and substantial improvement in health-related quality of life. The use of the NHP questionnaire to monitor changes in the subjective health of opioid-dependent patients over time provides new insights in the assessment of treatment effectiveness of methadone maintenance programmes.

Adult↗
PubMed1996

Retention in a low-threshold methadone maintenance program.

In 370 opioid-dependent patients included consecutively in a low-threshold methadone maintenance program, the effect of different variables on the retention rate was assessed. The variables included the patients' age, sex, family situation, employment status, length of heroin use, current route of drug consumption, previous treatments, current consumption of cocaine, alcohol and benzodiazepines, needle sharing, HIV serostatus and methadone dose. The retention rate after 2 years of methadone maintenance was 72%. Dose of methadone > 80 mg/day, age > 30 years, living with family or stable partner and non-current use of alcohol were significant predictive variables for retention.

Adult↗
PubMed1996

Clinical evaluation of the Triage analytic device for drugs-of-abuse testing.

In the present clinical evaluation of Triage immunoassay for detection of drugs of abuse, we examined a possible connection between the laboratory skills of the personnel using it and the quality of analytical results; we also evaluated the degree of concordance between the Triage results and those obtained by an instrumented fluorescence polarization immunoassay (FPIA). Three groups of evaluators with different laboratory skills and two sets of urine samples from subjects with different rates of drug consumption prevalence were included in the study. Urines were analyzed by the Triage analytical device at the collection site. A second analysis was performed in a toxicology laboratory, and the results were compared with those obtained by FPIA. Nonconcordant results were confirmed by gas chromatography-mass spectrometry and HPLC. Results were independent of the laboratory skills of the evaluators. The agreement for each drug calculated for two populations with differences in prevalence of drug consumption was almost the same, except for benzodiazepines. No differences between Triage and FPIA results were observed for samples clearly over or under cutoff concentrations. Globally, the Triage device, in a clinical situation, demonstrated performance comparable with that of an instrument-based immunoassay and, in some cases (e.g., for benzodiazepines), the Triage performance was even better.

Adult↗
PubMed1994

[Detection and evaluation of drug addict patients seen at a primary care center].

OBJECTIVE: Description of drug-dependent patients who attend a primary care centre (PCC). DESIGN: A prospective study. SETTING: Barceloneta PCC, located in a waterside area of Barcelona's old quarter. PATIENTS AND OTHER PARTICIPANTS: The analysis was carried out on 43 drug-dependent patients who attended the PCC over a two-year period requesting detoxication treatment as well as on patients who attended for treatment of other organic pathologies or to request medication and in whom an addiction problematic was detected. Patients who were already following a course of treatment in a specialised drug dependency centre or who were dependent on alcohol were excluded. INTERVENTIONS: Detection and evaluation of drug dependency and of hygienic-dietary problems. MEASUREMENTS AND MAIN RESULTS: A structured interview which looked at the drug history, sociodemographic characteristics and hygienic-dietary habits was employed. It was observed that 90.7% of the drug-dependent patients used heroin and 44% of these had not been previously treated for addiction. 88.4% were male and 51.2% had a criminal record. 72% practised one of the types of behaviour putting them at risk of HIV infection. CONCLUSIONS: The majority of patients addicted to drugs who were identified at a PCC are dependent on heroin as their primary drug. 44% of them had received no previous treatment for their addiction.

Adolescent↗