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.

Mitral valve replacement: a comparison of two prostheses.

Between November, 1965 and June, 1970, 175 patients underwent mitral valve replacement with the Smeloff-Cutter prosthesis (109 patients) or the toroidal valve (66 patients). The early mortality for patients with a toroidal mitral prosthesis was 18.2 percent (12 patients) and the late mortality 34.8 percent (23 patients). Among patients in whom Smeloff-Cutter mitral valves were inserted, the early mortality was 15.6 percent (17 patients) and the late mortality 23.9 percent (26 patients). During a follow-up period extending at least five years, thromboembolic complications occurred in 25.9 percent (14) of patients with toroidal valves and 7.6 percent (7) of patients with Smeloff-Cutter valves. Reoperation was necessary because of thrombosis of the prosthesis in seven patients with toroidal valves and two patients with Smeloff-Cutter valves. The incidence of endocarditis was the same in both groups. In this study, the Smeloff-Cutter mitral prosthesis proved to be superior to the toroidal valve because of a lower incidence of thromboembolism.

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.

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.

Fetal cardiac interval recorder.

A recorder is described which is capable of continuously measuring intervals between two events of the fetal cardiac cycle, as well as functioning as a routine intrapartum monitor. We have primarily measured the interval between the R wave of the fetal ECG and the second fetal heart sound (R-S2), but the recorder is also capable of measuring R-R, R-A0 (opening of aortic valve), R-Pl (placenta), and R-Sc (scalp) intervals. In the discussion, we endeavor to show that these intervals reflect fetal cardiac performance, which is altered by drugs and acidemia.

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.

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.

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.

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.

A preliminary evaluation of a modified needle-cleaning intervention using bleach among injection drug users.

This study examines an intervention designed to improve needle-cleaning practices among injection drug users (IDUs) in Dayton and Columbus, Ohio, to meet the recommended bleach exposure time of at least 30 seconds. Simulated needle-cleaning practices were observed in offices at baseline and after an intervention at 2 to 4 week and 6-month follow-ups. Descriptive statistics, t-tests, logistic, and multiple regressions were used to examine behavior change and the correlates of safer cleaning practices. At baseline (n = 541), the mean bleach exposure time was 13.8 seconds. At first follow-up (n = 410), the mean bleach contact time (23.4 s) increased significantly (t = 8.59; p < .05). At 6-month follow-up (n = 83), the mean bleach exposure time (21.1 s) also increased significantly (t = 2.98; p < .05). Longer bleach contact time was associated with higher injection frequency and needle transfer at 6-month follow-up. Although mean bleach exposure time increased significantly at both follow-ups, only 30.3% of the IDUs kept bleach in the syringe for at least 30 seconds at 6-month follow-up. Improved interventions are needed.

Conducting HIV outreach and research among incarcerated drug abusers: a case study of ethical concerns and dilemmas.

This case involves the examination of an ethically problematic event that arose while we were conducting an outreach/early intervention research demonstration project targeted at women who exchange sex for drugs. Subjects were drug abusers--primarily crack-cocaine smokers--recruited by outreach workers on "the street" and in jail. Participants were offered counseling, HIV and syphilis screening, and risk-reduction education. A woman who was a jail inmate tested positive for HIV. In order to obtain medical and other assistance, she would have to reveal her serostatus to jail officials. This could result in isolation and the possibility of harm from others in the jail once the information about her circulated. The case highlights the problems inherent in HIV testing of incarcerated drug abusers, especially in low HIV seroprevalence areas. We recommend that a community empanel a committee composed of substance abuse treatment and medical professionals, civil rights advocates, criminal justice personnel, and ethicists to formulate humane and effective policy in light of its drug abuse and HIV problems and its resources.

Crack-cocaine use and health status as defined by the SF-36.

The Medical Outcomes Study Short Form 36 (SF-36) was administered to 443 not-in-treatment, crack-cocaine smokers to explore the relationship between frequency of crack, alcohol, and tobacco use, addiction to these drugs, and health status. The reliability of the SF-36 with crack smokers was also assessed. Statistically significant, negative associations emerged between frequency of crack use and all SF-36 subscales except physical functioning. There were not significant associations between frequency of alcohol or tobacco use and any SF-36 subscale. Self-assessed addiction to crack was strongly and negatively associated with all SF-36 subscales: alcohol and tobacco addiction were also negatively associated with health status, but not to the degree of crack. The SF-36 produces reliable data on the health status of crack users and, as such, may have a useful role in assessments involving crack-using populations.

Crack-cocaine users as victims of physical attack.

This study evaluates the correlates of physical attack among people who use crack cocaine in Dayton, Ohio. Using a retrospective and prospective natural history design, data from baseline and 1-year follow-up interviews were used to calculate the prevalence of physical attack and the annual rate of physical attack suffered by 440 not-in-treatment crack-cocaine users. Logistic regression was used to determine the correlates of physical attack. The lifetime prevalence of physical attack was 63.0%; the annual rate was 36.8%. At baseline, daily crack users were more likely to report a previous attack since they began using crack (odds ratio [OR], 1.81; 95% confidence interval [CI], 1.18-2.77). Longer duration of crack use was also associated with experiencing an attack (OR, 1.09; 95% CI, 1.04-1.14). Between baseline and 12-month follow-up, the odds of men being attacked were significantly less than those for women (OR, 0.48; 95% CI, 0.23-0.99). Physical attack is widespread among crack-cocaine users, and does not vary by ethnicity. Injuries often result in the need for medical care. Over the short term, women are at increased risk. Accessible and effective drug abuse treatment is needed to diminish the harm this population suffers.

A comparison of total body water analyses: bioelectric impedance analysis versus the tritiated water method.

Bioelectric impedance analysis (BIA) is used to measure the body composition and total body water of normal subjects. The purpose of this study was to determine if the hydration of patients with burns could be assessed by BIA. Assessments of total body water as determined by BIA and the tritiated water method were prospectively compared. The 2 analyses were performed 48 hours after admission for 5 patients with acute burns to determine the correlation of the 2 methods. The patients had a mean age of 36.4+/-14.7 years (range, 20-56 years), a mean burn size of 39.4%+/-15.9% of the body surface area (range, 23%-65%), and a mean full-thickness burn size of 27.7% of the body surface area. The total body water was measured on admission and again at 48 hours postburn. There is an excellent relationship between BIA and tritiated-water-method determinations of the total body water of patients with severe burns (r = 0.958). This correlation suggests that BIA provides an accurate measure of total body water, and so it is a reliable means of monitoring fluid resuscitation in patients with burns.

Catalytic antibodies for complex reactions: hapten design and the importance of screening for catalysis in the generation of catalytic antibodies for the NDA/CN reaction.

Success in generating catalytic antibodies as enzyme mimics lies in the strategic design of the transition-state analog (TSA) for the reaction of interest, and careful development of screening processes for the selection of antibodies that are catalysts. Typically, the choice of TSA structure is straightforward, and the criterion for selection in screening is often binding of the TSA to the antibody in a microtiter-plate assay. This article emphasizes the problems of TSA design in complex reactions and the importance of selecting antibodies on the basis of catalysis as well as binding to the TSA. The target reaction is the derivatization of primary amines with naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide ion. The desired outcome is selective catalysis of formation of the fluorescent derivative in preference to nonfluorescent side-products. In the study, TSA design was directed toward the reaction branch leading to the fluorescent product. Here, we describe a microtiter plate-based assay that is capable of detecting antibodies showing catalytic activity at an early stage. Of the antibodies selected, 36% showed no appreciable binding to any of the substrates tested, but did show catalytic activity in derivatizing one or more of the amino acids screened. In contrast, only two out of 77 clones that showed binding did not show catalysis. Thus, in this complex system, observation of binding is a good predictor of the presence of catalytic activity, and failure to observe binding is a poor predictor of the absence of catalytic activity.

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.

Evaluation of HIV risk reduction intervention programs via latent growth model.

The latent growth model (LGM) has drawn increasing attention in behavioral studies using longitudinal data. The LGM captures the level and trajectory of behavior change, variation in both the initial status and the trend of behavior change, as well as the time-ordered covariation between the initial status and change. This study demonstrates how the LGM can be applied in the evaluation of intervention programs targeting HIV risk behavior among drug users. Multi-group piecewise latent growth models were fit to longitudinal data with three repeated response measures.

The crack life: an ethnographic overview of crack use and sexual behavior among African-Americans in a midwest metropolitan city.

The use of crack cocaine and its associations with high-risk sexual behavior in view of the AIDS epidemic is reported commonly for major East and West Coast urban centers. This article describes and analyzes ethnographic data on crack use in Dayton, Ohio, a small midwestern city of less than 200,000 people. The results of 15 tape-recorded interviews are employed to sketch the basic outlines of crack use among African-Americans. A major focus is placed on analyzing the characteristics of the exchange of crack for sexual favors. High-risk behaviors for the transmission of HIV and other sexually transmitted diseases are explored.

HIV needle risk behaviors and drug use: a comparison of crack-smoking and nonsmoking injection drug users in Ohio.

This study compares the drug use and needle risk behaviors among 733 crack-smoking injection drug users (IDUs) and 518 nonsmoking IDUs. Participants were recruited in Dayton and Columbus, Ohio, for the Cooperative Agreement for AIDS Community-Based Outreach/Intervention Research Program from 1992 to 1996. Crack-smoking IDUs were more likely to be male, African-American, and 30 to 40 years of age, but less likely to be married or living with a sex partner compared to nonsmokers. Daily crack users were less likely to be daily injectors but more likely to use alcohol daily when compared to non-crack users and less-than-daily crack smokers. IDUs who smoked crack less than daily were more likely to have injected with needles and syringes used by others. There is an urgent need for additional research on the relationship between drug injection and crack smoking as well as improved HIV risk-reduction interventions that include drug abuse treatment components focusing on issues surrounding crack-cocaine addiction.

Injection drug users in the Midwest: an epidemiologic comparison of drug use patterns in four Ohio cities.

Variations in the drug use patterns of injection drug users (IDUs) can have important implications for public health efforts aimed at reducing drug abuse and the transmission of the human immunodeficiency virus. This article describes and compares the characteristics of IDUs living in four Ohio cities and compares African-American and White IDUs at a statewide level. Data from 2,001 IDUs who were recruited for the National AIDS Demonstration Research project between 1989 and 1991 in Columbus, Cleveland, Cincinnati, and Dayton were compared on a number of variables by city and by ethnicity using descriptive statistics and ANCOVA analysis. Significant differences among IDUs in the four cities exist for the use of alcohol, marijuana, cocaine, crack, heroin, speedball, other opioids, shooting gallery use, "safer" needle practices, treatment history, and self-help participation. Differences by ethnicity emerged on all variables except marijuana use, overall injection frequency, and incarceration experience. The results suggest that dramatic differences exist between African-American and White IDUs, and among IDUs in cities relatively close together, regardless of ethnicity. These findings should be considered when developing policy and programs for prevention and treatment activities targeting IDUs.