Injection drug users, crack smokers, and the use of human services.
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Adult↗
Biomedical subjects
R G Carlson
Publications and source records attributed to R G Carlson.
Reducing HIV needle risk behaviors among injection-drug users in the Midwest: an evaluation of the efficacy of standard and enhanced interventions.
This study compares the impact of a standard and an enhanced intervention on the needle-use behaviors reported by injection-drug users (IDUs) living in a low-seroprevalence area in the Midwest. Data on the drug- and needle-use practices of 381 IDUs completing a standard (n = 232) or an enhanced (n = 149) intervention who were followed-up five to nine months after a baseline interview were analyzed using bivariate and multivariate techniques. The results indicate that IDUs who participated in the enhanced intervention reported safer needle practices than standard intervention IDUs at follow-up. In addition, less frequent injectors were much more likely to adopt safer needle-use practices than were daily drug injectors, regardless of intervention track. The results suggest that more intensive interventions have advantages over minimalist efforts--in specific contexts. This finding has important implications for the HIV needle risk-reduction efforts targeting IDUs.
Adult↗
Injection drug users, crack-cocaine users, and human services utilization: an exploratory study.
Estimates of the number of people addicted to heroin and cocaine run into the millions. How these drug abusers interact with the social services system is not well understood. To gain insight into the nature and extent of such interactions, an exploratory study was conducted to gather information on the perceptions and utilization of human services by 44 drug abusers not in treatment. Twenty-nine injection drug users and 15 crack-cocaine users participated in focus group sessions and structured interviews. Participants were recruited by indigenous outreach workers in Dayton and Columbus, Ohio. Findings revealed a very high rate of service use by the drug users. The results raise questions about the role and efficacy of the social services system in identifying drug users and addressing their needs. In addition, the findings raise perplexing questions regarding the effectiveness of acquired immune deficiency syndrome risk-reduction efforts among injection drug users and crack-cocaine users.
Adult↗
Qualitative research methods in drug abuse and AIDS prevention research: an overview.
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Acquired Immunodeficiency Syndrome↗
Usefulness of the health belief model in predicting HIV needle risk practices among injection drug users.
A health belief model (HBM) that included the dimensions of perceived susceptibility, seriousness, benefits, barriers, and self-efficacy was employed to predict which injection drug users (IDUs) were engaged in needle-use practices that reduced their risk for contracting the human immunodeficiency virus (HIV). A sample of 118 active IDUs, many of whom also used crack cocaine, responded to interviewer-administered questionnaires that gathered information on their drug-use practices in the last thirty days, as well as their health beliefs. Logistic regression analysis revealed that two health beliefs--perceived self-efficacy (OR = 1.27, 95% CI = 1.04, 1.55) and perceived susceptibility (OR = .82, 95% CI = .71, .94)--were significantly related to safer injection practices. Other predictors of safer injection were black ethnicity (OR = 3.18, 95% CI = 1.19, 8.47) and injection frequency (OR = .99, 95% CI = .98, .99). The results of this study suggest that the HBM has a role to play in risk-reduction programs targeting IDUs.
Adult↗
Injection drug users' needle-cleaning practices.
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Disinfection↗
Case management to enhance HIV risk reduction among users of injection drugs and crack cocaine.
Case management is being applied to increasingly diverse client populations. This article describes the application of a field-based, service-broker model of case management with a population of injection drug users and crack cocaine users within the context of an AIDS risk-reduction program. The major problem encountered involved client engagement. The feasibility of implementing an effective case management program with active users of injection drugs and crack is questionable so long as involvement with such drugs is cast primarily as a criminal justice problem.
Adult↗
Isolation of endogenous modulators for the GABAA and taurine receptors.
Several endogenous brain substances which inhibit [3H]muscimol binding were isolated, and one of them has been purified to apparent homogeneity. The purification involved the extraction of brain tissue with water, followed by several steps of gel filtration column chromatography and high performance liquid chromatography (HPLC). The muscimol binding inhibitor (MBI) thus obtained appeared to be homogeneous as judged from the elution profile of an HPLC column, in which a symmetrical peak was obtained when the eluate was monitored at either 220 or 280 nm. Furthermore, the MBI activity coincided with the absorption peak. The purified MBI is not gamma-amino butyric acid (GABA), beta-alanine or taurine since these amino acids are clearly separated from the MBI in the purification procedures. The MBI has no effect on benzodiazepine (BZ) binding or glutamate binding to their respective receptors. However, the MBI is a more potent inhibitor for [3H]taurine binding than that of [3H]muscimol binding. The MBI appears to be a small molecule (< 2000 Da) that is heat and acid/base stable. The chemical nature of the MBI is currently under investigation.
Animals↗
Does selective vagotomy prevent delayed gastric emptying and altered myoelectric activity following Roux-en-Y gastrojejunostomy?
Delayed gastric emptying occurs frequently following Roux-en-Y gastrojejunostomy. The role of vagal denervation in the etiology of this "Roux-stasis syndrome" is controversial. This study evaluates the effect of selective vagotomy on gastric emptying and motility following Roux-en-Y. Four dogs underwent control gastric emptying studies. The animals then underwent selective vagotomy, antrectomy, and Billroth II gastrojejunostomy, with placement of serosal electrodes. Gastric emptying was assessed with simultaneous myoelectric recordings, and the animals were converted to Roux-en-Y, followed by repeat studies. Gastric emptying was unchanged following selective vagotomy, antrectomy, and Billroth II gastrojejunostomy (T 1/2: 132 +/- 18 min [SEM] versus 118 +/- 14 min control) but was markedly delayed following Roux-en-Y diversion (T 1/2: 286 +/- 44 min; p less than 0.01). All animals went into the fed pattern following Billroth II gastrojejunostomy (migrating myoelectric complex [MMC] interval: 326 +/- 6 min postprandial versus 92 +/- 5 min fasting; p less than 0.01), but no fed pattern was recognized in three of four animals following Roux-en-Y diversion (MMC interval: 68 +/- 12 min postprandial versus 62 +/- 1.5 min fasting; p = NS). In a canine model, selective vagotomy does not prevent delayed gastric emptying or myoelectric alterations following Roux-en-Y.
Anastomosis, Roux-en-Y↗
Symbolic mediation and commoditization: a critical examination of alcohol use among the Haya of Bukoba, Tanzania.
Low-alcohol-content fermented beverages are thoroughly enmeshed in the social, economic, commensal, and cosmological spheres of life among most peoples of sub-Saharan Africa. This paper describes and analyzes the role of alcoholic beverages as symbolic mediators and commodities among the Haya of northwest Tanzania. Data gathered during field research in 1985-86 are employed to describe the ways in which the Haya portray excessive drinking and the indigenous strategies they use to address frequent drunkenness when it is perceived as a health problem. A central feature of the paper contrasts the role of a cultural schema of four levels of intoxication in processes of symbolic mediation and commoditization, thereby contributing to critical medical anthropological analysis.
Alcohol Drinking↗
Case management to enhance AIDS risk reduction for injection drug users and crack cocaine users: practical and philosophical considerations.
The AIDS intervention model described herein represents a new "mixed" model of case management, one that combines AIDS risk-reduction education with a modified version of the traditional broker of services model. The case management component of the model is designed to heed and address those immediate needs that may distract a person from attending to the AIDS risk-reduction messages. The educational component of the model can help a person develop interest in the case management services. The result is a model that, theoretically, can have a greater impact than either component alone would have. The advantages of the model are its flexibility, its ability to quickly assess and address clients' concerns, and its short duration that enhances the likelihood that drug users will complete the process.
Acquired Immunodeficiency Syndrome↗
Erythromycin enhances delayed gastric emptying in dogs after Roux-Y antrectomy.
Delayed gastric emptying occurs in up to 50% of patients after truncal vagotomy and Roux-Y antrectomy and is often resistant to nonsurgical therapy. This study evaluates the effect of erythromycin, metoclopramide, and motilin on delayed gastric emptying in four dogs after Roux-Y antrectomy. Solid food gastric emptying was measured using a radionuclide technique. Study groups were: (1) saline control; (2) erythromycin 1 mg/kg intravenously over 1 hour; (3) erythromycin 3 mg/kg by mouth 45 minutes prior to feeding; (4) metoclopramide 0.6 mg/kg intravenously over 1 hour; and (5) motilin 500 ng/kg intravenously over 1 hour. After Roux-Y antrectomy, saline control dogs had 73% +/- 5% (SEM) gastric retention at 2 hours. After intravenous and oral erythromycin, gastric emptying improved at 2 hours to 27% +/- 6% and 39% +/- 5% (p less than 0.01 compared with control). Erythromycin intravenously and by mouth improved gastric emptying compared with metoclopramide (64% +/- 8%, p less than 0.05). Motilin enhanced gastric emptying to a similar degree as erythromycin, with a 2-hour gastric retention of 37% +/- 4% (NS). Erythromycin improved gastric emptying in dogs with severe Roux-Y gastroparesis and may have clinical application.
Administration, Oral↗
Erythromycin acts through a cholinergic pathway to improve canine-delayed gastric emptying following vagotomy and Roux-Y antrectomy.
We have demonstrated that erythromycin improves gastric emptying in dogs following truncal vagotomy and Roux-en-Y antrectomy (VRYA). To explore its mechanism of action we studied gastric emptying and myoelectric activity in a canine Roux model and administered atropine simultaneously with erythromycin. Tachyphylaxis was evaluated following short-term administration. Four dogs with delayed gastric emptying following VRYA were studied. Radionuclide solid gastric emptying was measured, with simultaneous myoelectric recordings obtained from the duodenum and Roux limb. Study groups were: (1) saline control (VRYA dogs); (2) erythromycin 1 mg/kg iv over 1 hr; (3) erythromycin 3 mg/kg po tid for 1 week, with repeat studies using erythromycin 1 mg/kg iv over 1 hr; and (4) atropine 0.5 mg/kg iv bolus, followed by a 1-hr infusion of atropine 0.05 mg/kg and erythromycin 1 mg/kg. Control Roux animals had severe gastric retention (73 +/- 5% at 2 hr, compared to 27 +/- 6% following iv erythromycin (P less than 0.01). Clustered spike bursts were observed in the Roux limb following erythromycin. Atropine abolished the gastrokinetic response and suppressed the myoelectric response to erythromycin (81 +/- 3% retention at 2 hr, P less than 0.01 compared to erythromycin alone). The response to erythromycin was unchanged after 1 week of tid administration (40 +/- 14% retention at 2 hr postprandial, P = NS). Erythromycin improves gastric emptying in VRYA dogs via a cholinergic pathway and does not exhibit tachyphylaxis following short-term administration.
Anastomosis, Roux-en-Y↗
Radiation-associated valvular disease.
The prevalence of radiation-associated cardiac disease is increasing due to prolonged survival following mediastinal irradiation. Side effects of radiation include pericarditis, accelerated coronary artery disease, myocardial fibrosis and valvular injury. We evaluated the cases of three young patients with evidence of significant valvular disease following mediastinal irradiation. One patient underwent the first reported successful aortic and mitral valve replacement for radiation-associated valvular disease (RAVD) as well as concurrent coronary artery revascularization. A review of the literature revealed 35 reported cases of RAVD, with only one successful case of valve replacement that was limited to the aortic valve. Asymptomatic RAVD is diagnosed 11.5 years after mediastinal irradiation compared with 16.5 years for symptomatic patients, emphasizing that long-term follow-up is important for patients receiving mediastinal irradiation. This study defines a continuum of valvular disease following radiation that begins with mild asymptomatic valvular thickening and progresses to severe valvular fibrosis with hemodynamic compromise requiring surgical intervention.
Adolescent↗
HIV infection and risk behaviors among intravenous drug users in low seroprevalence areas in the Midwest.
We studied behavioral factors that place intravenous drug users at risk for the acquisition and transmission of the human immunodeficiency virus (HIV) in a sample of 855 individuals not in drug treatment, living in central and southwestern Ohio. The HIV seropositivity rate for the sample was 1.5%. Three factors were significantly related to HIV infection: homeless shelter residence (odds ratio [OR] = 7.7, 95% confidence interval (CI) = 3.0-20.0), travel to northeastern HIV hyperendemic areas (OR = 5.2, 95% CI = 1.8-15.4), and recent male homosexual or bisexual behavior (OR = 11.2, 95% CI = 2.9-43.9).
Adult↗
Oxalate/hydrogen peroxide chemiluminescence reaction. A 19F NMR probe of the reaction mechanism.
The mechanism of the oxalate/hydrogen peroxide chemiluminescence reaction has been examined by magnetic resonance techniques. Investigation of the reactive intermediates involved in chemiluminescence was carried out with bis(2,6-difluorophenyl)oxalate (DFPO) using 19F NMR to probe its reactions with aqueous hydrogen peroxide. Formation and reactions of the intermediate hydroperoxy oxalate ester B along with the formation of the half ester product C and difluorophenol D were monitored by 19F NMR. When the reaction of DFPO and aqueous hydrogen peroxide was carried out in the presence of dansylphenylalanine, a typical fluorescent analyte, the intensity of the resonance due to the intermediate B was diminished in direct proportion to the concentration of the analyte. Comparison of the time/intensity profile of the chemiluminescence emission with that of the 19F NMR transient suggests that the hydroperoxy oxalate ester B is the likely 'reactive' intermediate, capable of participating in a chemically initiated electron exchange luminescence mechanism.
Fluorine↗
Altered motility and bacterial flora after functional end-to-end anastomosis.
The functional end-to-end technique with a gastrointestinal stapler is commonly used for small-bowel anastomosis, but the effects of this anatomically side-to-side anastomosis on motility are unknown. Fasting small-bowel myoelectric activity and culture results were compared in six animals undergoing handsewn end-to-end and functional end-to-end anastomoses. Serosal electrodes were placed at 10 cm intervals, and the small bowel was divided 25 and 55 cm from the ligament of Treitz. The functional end-to-end and end-to-end techniques were performed in each animal in random order. Fasting myoelectric recordings were obtained at weekly intervals for up to 20 weeks after operation. New electrodes were placed, and additional recordings were obtained from 29 to 39 weeks, 51 to 63 weeks, and 108 to 112 weeks after operation. The recordings were visually inspected for passage of phase 3 of the migrating myoelectric complex (MMC). By 12 to 20 weeks after operation, 91% of MMCs crossed the end-to-end anastomoses versus 22% across the functional end-to-end anastomosis (p less than 0.001). Even 2 years after surgery only 56% of MMCs crossed the functional end-to-end anastomosis. Quantitative bacterial cultures suggested a trend toward bacterial overgrowth in the functional end-to-end anastomosis. These results demonstrate that the functional end-to-end anastomosis alters small-bowel motility to a greater degree than an end-to-end anastomosis and may predispose to bacterial overgrowth.
Anastomosis, Surgical↗
Pathogenesis of cardiovascular alterations in dogs treated with minoxidil.
Minoxidil and other potent vasodilators cause coronary arterial injury, right atrial hemorrhagic lesions, and subendocardial necrosis in dogs. This paper discusses the pathogenesis of coronary arterial and right atrial lesions associated with minoxidil in the dog. Acute coronary vascular injury characterized by segmental medial hemorrhage and necrosis and perivascular inflammation occurred only during the first few days of treatment, after which tolerance to further acute injury developed. At 30 d or more of treatment, coronary vascular injury was characterized by perivascular fibrosis rarely attended by medial distortion or hyperplasia and subintimal thickening, changes consistent with responses to previous injury. Right atrial hemorrhagic lesions, unlike coronary vascular injury, often became progressively more extensive with continued treatment. At 3 d, atrial hemorrhage and inflammation were confined to the subepicardium of the right atrium, evidently around affected subepicardial branches of the right coronary artery. At 30 d, fibrovascular proliferative right atrial lesions (granulation tissue with evidence of continual hemorrhage) extended from the epicardium to the myocardium, with eventual replacement of the atrial wall by mature connective tissue at 1 yr of treatment. Minoxidil-induced cardiovascular lesions were not prevented by treatment with a beta-blocker (propranolol), or an alpha-blocker (dibenzylene), or by sympathetic neural activity suppression (surgical sympathectomy or constant carotid sinus nerve stimulation), suggesting that the sympathetic response to the pharmacologic activity of minoxidil was not responsible for the induction of the cardiovascular lesions. Minoxidil-related vascular lesions were confined to the most pharmacologically responsive segment of the arterial system, the coronary arteries, suggesting that medial injury may have been associated with tensile changes in the arterial wall.
Adrenergic beta-Antagonists↗