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Biomedical subjects

M C Doherty

Publications and source records attributed to M C Doherty.

14 recordsLinked to original sources
PubMed2001

Implementation of the STOP protocol for Stroke Prevention in Sickle Cell Anemia by using duplex power Doppler imaging.

PURPOSE: To compare the results of the nonduplex ultrasonography (US) Stroke Prevention Trial in Sickle Cell Anemia (STOP) with those of transcranial duplex power Doppler US by using the STOP protocol and to correlate abnormal transcranial Doppler findings with magnetic resonance (MR) imaging and MR angiographic findings. MATERIALS AND METHODS: One hundred twenty-five asymptomatic patients aged 2-16 years with sickle cell anemia or sickle cell-beta thalassemia were examined by using transcranial duplex power Doppler US with a 2.5-MHz transducer and classified according to STOP criteria. The results were compared with those obtained in the nonduplex STOP study. Eight of 10 patients with abnormal results, as well as one who had normal results and a subsequent stroke, were examined with MR imaging and MR angiography. RESULTS: Ten (8.0%) patients were judged to have abnormal findings by using the duplex Doppler US and STOP criteria compared with 9.4% of patients in the nonduplex US STOP study. Of the eight patients with abnormal transcranial Doppler US results who underwent MR imaging and MR angiography, six had abnormal MR imaging findings and all eight had abnormal MR angiographic findings. CONCLUSION: The STOP protocol can be reproduced by using duplex power Doppler US. Abnormal results with the STOP criteria strongly suggest vascular abnormality.

Adolescent↗
PubMed2000

Correlates of HIV infection among young adult short-term injection drug users.

OBJECTIVES: To identify risks associated with HIV infection among young adult short-term injection drug users. METHODS: Current injection drug users, between 18 and 29 years of age, were recruited through street outreach to participate in a cross-sectional survey of HIV prevalence by circumstances of drug injection initiation, HIV-related risk behaviors, and a follow-up to estimate HIV incidence. RESULTS: At enrollment, 33 (14.4%) of 229 participants were HIV-seropositive. Significant bivariate associations with HIV at the time injection drug use was initiated included age less than or equal to 18 years, having receptive anal sex with the person who assisted with initiation, and having two or more 'trainers' before being able to self-inject. Injecting risks positively associated with HIV included cocaine or speedball (heroin and cocaine together) injection versus heroin or amphetamine injection, injecting five or more times per day, daily crack smoking, backloading, sharing needles at peak drug use, and not using a new needle for every injection. Sexual practices associated with HIV included reporting > 100 lifetime sex partners, a history of sexual assault, being gay or bisexual, and trading sex for money or drugs after starting to inject. In a multivariate model, trading anal sex for money or drugs after initiating injection drug use [odds ratio (OR), 14.2; 95% confidence interval (CI) 3.2-62.3], cocaine/speedball injection (OR, 10.3; 95% CI, 2.2-47.9), daily crack smoking (OR, 4.2; 95% CI, 1.7-10.5), and having two or more trainers (OR, 2.6; 95% CI, 1.1 - 5.9) were independently associated with HIV. During 12 months of follow-up, four persons seroconverted for HIV (annual incidence: 2.6%; 95% CI, 1.1 -5.9%) CONCLUSIONS: Among short-term injectors, both sexual and injecting practices were important predictors of HIV infection, indicating that a proportion of HIV infections among young injection drug users can be attributed to sexual transmission. The incidence rate for HIV infection suggests that immediate steps should be taken to prevent new infections among young injection drug users.

Adolescent↗
PubMed2000

Gender differences in the initiation of injection drug use among young adults.

To characterize the circumstances surrounding initiation of injecting drug use, data were collected from 229 young, recently initiated injection drug users enrolled through community-based recruitment in Baltimore, Maryland. Gender differences in the pattern of initiation, the number of persons present at initiation, risky injection, and sexual behaviors at initiation, as well as behaviors after initiation, were examined. Overall, men and women were similar statistically with respect to age at initiation (19.5 years) and risk behaviors at initiation. While men were initiated by men (77%), women were more often initiated by women (65%), most of whom were friends (75%) or relatives (23%). The percentage of women infected with human immunodeficiency virus (HIV) was slightly greater than that of men, 17% versus 11% (P < .2), whether initiated by a man or a woman. Persons who self-initiated had a lower HIV prevalence and fewer HIV-related risk behaviors. Analysis of variance assessed differences in the HIV risk profiles of female and male IDUs who were initiated by someone of the same sex, of the opposite sex, or who self-initiated. These results indicated that (1) young women and men had similar patterns of injection initiation; (2) most women were initiated by female friends, running counter to earlier literature claims that women were initiated to injection drug use by male sex partners; and (3) women initiated by men had a marginally greater mean score on the HIV risk profile.

Adolescent↗
PubMed2000

How cigarette additives are used to mask environmental tobacco smoke.

OBJECTIVE: To understand the tobacco industry's research on and use of cigarette additives that alter the perception of exposure to environmental tobacco smoke (ETS). DATA SOURCES: Internal documents from four websites maintained by the major US tobacco manufacturers and company patents pertaining to the use of ETS altering additives obtained from the US Patent and Trademark Office online database. STUDY SELECTION: Electronic searches of the four industry websites and the US patent database were conducted using keywords to identify relevant data. DATA EXTRACTION: Industry documents and patents obtained using an exploratory snowball sampling method were reviewed and grouped into four general categories according to whether the additive(s) described affected ETS visibility, odour, irritation, or emissions. Accuracy of isolated findings was validated through cross comparison of the data sources. DATA SYNTHESIS: Results of this preliminary study provide evidence that tobacco manufacturers have conducted extensive research on the use of chemical additives to reduce, mask, or otherwise alter the visibility, odour, irritation, or emission of ETS. CONCLUSIONS: Findings suggest that the tobacco industry uses additives to reduce the perception of ETS. To protect the public, appropriate regulation of tobacco additives should be mandated.

Humans↗
PubMed2000

The effect of a needle exchange program on numbers of discarded needles: a 2-year follow-up.

OBJECTIVES: This study estimates the quantity and geographic distribution of discarded needles on the streets of Baltimore, Md, during the 2 years after a needle exchange program opened. METHODS: Thirty-two city blocks were randomly sampled. Counts were taken of the number of syringes, drug vials, and bottles before the needle exchange program opened and then at 6 periodic intervals for 2 years after the program opened. Nonparametric and generalized estimating equation models were used to examine change over time. RESULTS: Two years after the needle exchange program opened, there was a significant decline in the overall quantity of discarded needles relative to that of drug vials and bottles (background trash). The block mean of number of needles per 100 trash items was 2.42 before the program opened and 1.30 2 years later (mean within-block change = -0.028, P < .05). There was no difference in the number of discarded needles by distance from the program site. CONCLUSIONS: These data suggest that this needle exchange program did not increase the number of distribution of discarded needles.

Baltimore↗
PubMed1999

HIV prevalence and risk behaviors among new initiates into injection drug use over the age of 40 years old.

Injection drug users (IDUs) who have recently initiated an injecting career have high risk behaviors for HIV infection. The average age of an IDUs first injection is typically reported as 19-20 years, and some literature has reported 'maturing out' of drug use typically around 40 years old. The purpose of this study was to discriminate risk behaviors among newer injectors by age of initiation. This cross-sectional study includes volunteers enrolled using extensive community recruitment techniques in 1988 and 1989 in Baltimore, MD. Of the 722 injection drug users who had initiated injection within the prior six years, 124 were over 35 years old of whom 53 were 40 years and older. Rates of HIV were lower among those over 40 years (13.2%) than those who were 35-39 years (22.5%) or under 35 years old (20.9%). The behavioral characteristics of those aged 35-39 were similar to those under 35 years old, but those over 40 years old when compared with less than 39 years reported injecting at least daily less frequently (88.7% vs 76.5%, p = 0.042), using a needle from a sterile wrapper (19.0% vs 36.6%, p = 0.006), and injecting with their own works (52.6% vs 28.8%, p = 0.021). This study shows that people initiate injection drug use across a wide age range and that needle hygiene practices early after initiation tend to be safer in older compared to younger initiates.

Adult↗
PubMed1998

Prevalence and incidence of hepatitis C virus infection among young adult injection drug users.

Through community-based outreach, young adult injection drug users (IDUs) were enrolled in a prospective study of the prevalence, incidence, and risk factors for hepatitis C virus (HCV) infection. Demographics and information on sexual and injecting practices were collected during semiannual interviews, and HCV infection was evaluated using a second-generation antibody assay. Of the 229 participants, 86 (37.6%) were HCV-seropositive at baseline. After adjusting for injecting frequency and duration by logistic regression, HCV seroprevalence was independently associated with reusing syringes at least once in the past 6 months (odds ratio [OR]=3.81, 95% confidence interval [CI] 1.39-11.00), injecting the first time with someone > or =5 years older (OR=2.99; 95% CI, 1.43-6.23) or alone (OR=4.02; 95% CI, 1.12-14.43) versus with someone <5 years older, and injecting cocaine or speedball exclusively (OR=4.29; 95% CI, 1.53-12.01) or with other drugs (OR=5.27; 95% CI, 2.62-10.64) versus injecting no cocaine in the past 6 months. Of the 105 originally HCV-seronegative participants who returned for follow-up, 13 seroconverted (incidence rate=16.0/100 person-years). On bivariate analysis, HCV seroconversion was significantly associated with injecting for <2 years (relative risk [RR]=7.3; 95% CI, 1.6-32.8) and continuing to inject during follow-up (RR=4.4; 95% CI, 1.0-19.9). Young adult IDUs are at high risk for HCV infection. These data support the need for wider legal access to sterile syringes, as well as expanded community outreach education to this population to prevent transmission of HCV.

Adult↗
PubMed1998

Gender differences in injection-related behaviors among injection drug users in Baltimore, Maryland.

Baseline data from 640 injection drug users in the Stop AIDS for Everyone study, an HIV preventive intervention were used to examine gender differences in self-reports of injection behaviors. In both the bivariate and multivariate analyses men reported injecting alone, in semipublic areas, and at their mother's residence more often than women. In the bivariate analyses, women reported denser personal networks, and in the multivariate analyses, women reported significantly greater overlap between their drug and sex networks. These data suggest that this overlap of sex and drug networks may reduce women drug injectors' ability to adopt and maintain HIV protective behaviors. The data also suggest that interventions need to address gender differences in the social context of risk behaviors.

Adult↗
PubMed1997

Discarded needles do not increase soon after the opening of a needle exchange program.

This study examines the effect of a Needle Exchange Program (NEP) on the quantity and geographic distribution of discarded needles on the streets of Baltimore, Maryland, and presents methods to survey discarded needles in the community. A random sample of 32 city blocks located within high-drug-use census tracts, stratified by east and west sides of the city and by proximity to the NEP, was selected for survey. Three teams surveyed the number of needles and the number of drug vials and unbroken glass bottles ("trash") to control for practice effects. Surveillance was conducted prior to initiation of the NEP in August 1994 and 1 and 2 months thereafter. Over the three study periods, the absolute count of discarded needles was 106, 130, and 128, respectively; the number of vials and bottles was 3,048, 3,825, and 3,796, respectively. The initial nonstatistically significant increase in needles (mean change = 0.38, 95% confidence interval (CI) -0.18 to 0.93) was offset by accounting for background trash. Regression models fitted with the generalized estimating equation method, which accounted for within-block correlation over time, showed no significant increase in the number of needles after adjustment for trash during the first 2 months of the NEP's operation. These data suggest that the initiation of NEPs does not result in an increase in the number of discarded needles on the street.

Baltimore↗
PubMed1996

Viral infections in short-term injection drug users: the prevalence of the hepatitis C, hepatitis B, human immunodeficiency, and human T-lymphotropic viruses.

OBJECTIVES: The purpose of this study was to estimate the prevalence and correlates of four blood-borne viral infections among illicit drug injectors with up to 6 years of injecting experience. METHODS: We analyzed data from 716 volunteers recruited in 1988 and 1989. Test results for hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus, type 1 (HIV), and human T-lymphotropic virus types I and II (HTLV) were examined across six sequential cohorts defined by duration of drug injection. RESULTS: Overall, seroprevalence of HCV, HBV, HIV, and HTLV was 76.9%, 65.7%, 20.5% and 1.8%, respectively, and 64.7%, 49.8%, 13.9%, and 0.5%, respectively, among those who had injected for 1 year or less. Among the newest initiates, HCV and HBV were associated with injecting variables, and HIV was associated with sexual variables. CONCLUSIONS: The high rates of HCV, HBV, and HIV infections among short-term injectors emphasizes the need to target both parenteral and sexual risk reduction interventions early. Renewed efforts at primary prevention of substance abuse are indicated.

Adolescent↗
PubMed1995

Acquisition and use of needles and syringes by injecting drug users in Baltimore, Maryland.

Our objective was to determine how injection drug users (IDUs) in Baltimore, Maryland obtain and use needles and syringes (NS) for drug injection, before the opening of a needle exchange program (NEP). The method of this study was a cross-sectional structured interview survey in 1992 of active IDUs in a longitudinal study of human immunodeficiency virus (HIV) infection. For 466 IDUs (94.6% black, 83% male), usual sources of NS were "street" dealers (49.6%), pharmacies (29.8%), diabetics (16.3%), friends/neighbors (2.2%), and "shooting galleries" (1.9%). Half (53.5%) reported pharmacy purchase of NS, and 55.6% had diabetic friends/relatives. Twenty-three percent traded drugs, and 5% traded sex for NS. Eighty-eight and two-tenths percent would use a needle exchange program; 24.6% currently own no NS (median owned = 2.2). NS reuse was common (median = three times). Concern about (55.2%) or history of (33.9%) hassle/arrest for NS possession was typical; 81% kept NS at home, and 67% do not carry NS when purchasing drugs. Pharmacy purchasers (versus "street") were less likely to have been jailed, shared NS, or used shooting galleries during the preceding 6 months. In Maryland, although IDUs can legally purchase NS at pharmacist discretion, possession remains illegal; fewer than one-third of IDUs use pharmacies, and most obtain NS from illegal sources. Most IDUs reuse NS, but discard them after several uses. Current patterns of NS acquisition and use in Baltimore are likely to increase HIV transmission. Increased availability and decriminalization of NS possession could decrease the risk of injection-related HIV transmission.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Inadequate bleach contact times during syringe cleaning among injection drug users.

Objectives were to measure syringe cleaning strategies used by injection drug users (IDUs) and to assess syringe contact with bleach during cleaning demonstrations. IDUs were interviewed about cleaning activities during their most recent injection episode; they demonstrated these activities on videotape. Coders reviewed the videotapes, categorized activities, and used stop watches to record bleach exposure. Of 161, 146 subjects reported cleaning at last injection, 85 (58%) of 146 used full strength bleach. Of bleach users, 20% had total contact time (duration of bleach inside syringe) of > or = 30 s; combining draw (time taken to fill syringe) and contact times, 54% of bleach users had total "flush" times of > or = 30 s. Median observed time per bleach flush was 16 s. Median reported cleaning times were twice as long as observed. Recent reports indicate 30 s of exposure to undiluted bleach is necessary to inactivate HIV in the laboratory; here, 80% of IDUs using bleach had contact of < 30 s. Judgment of contact time was inaccurate. On average, instructions advocating two bleach flushes may reach 30 s; here, half the subjects had insufficient time with two flushes. The majority showed inadequate techniques, therefore, alternate cleaning strategies should be developed.

Adult↗
PubMed1987

Ferroxidase II activity and serum cholesterol.

Ferroxidase II (Fox II) was developed in serum by acid incubation for 24 h. The resulting activity showed a strong positive correlation with the serum cholesterol concentration in normal subjects and patients with hyperlipidaemia. The potentiating effect of cholesterol on developed Fox II has been confirmed by the in-vitro addition of cholesterol to serum. There was no significant correlation between developed Fox II and caeruloplasmin (ferroxidase I) or between cholesterol and caeruloplasmin.

Ceruloplasmin↗