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Biomedical subjects

S Cohn

Publications and source records attributed to S Cohn.

At least 55 records · Page 3Linked to original sources

A pilot syringe exchange program in Washington, DC.

The Washington, DC City Council authorized a pilot syringe exchange program to operate for only 60 days at a single drug abuse treatment facility in the District. Only adults on the waiting list for treatment were eligible (n = 467). Of the 33 who enrolled, median duration of drug injection was 18 years. Twenty-seven participants denied needle sharing. Of 209 needles distributed, 69% were returned. Low enrollment might have been due to restrictive entry criteria, inconvenient location, incorrect syringe size, and attitudes of treatment staff. For future efforts to have a public health impact, wider accessibility will be needed.

Adult↗

Correlates of needle sharing among injection drug users.

OBJECTIVES: The sharing of contaminated injection equipment is the primary mode of human immunodeficiency virus (HIV) transmission for injection drug users. This study examined demographic factors, life events, and drug use practices that are potential risk factors for sharing injection equipment. METHODS: Between February 1988 and March 1989, 2921 active injection drug users were interviewed and questioned about their backgrounds, life-styles, and patterns of injection drug use. RESULTS: Of 2524 participants who reported injecting drugs within the 6 months prior to study enrollment, 70.4% reported recent needle sharing. A multivariate analysis found needle sharing to be more frequent among those with a history of arrest and lower socioeconomic status, even after accounting for other demographic and drug use variables. In addition, recent needle sharing was higher in male homosexual or bisexual men than in their heterosexual counterparts. CONCLUSIONS: These data suggest that injection drug users have an economic motive to share needles and that the availability of free and legal needles may reduce levels of needle sharing.

Adult↗

Comparison of clinical symptoms of human immunodeficiency virus disease between intravenous drug users and homosexual men.

BACKGROUND: To compare the prevalence of human immunodeficiency virus (HIV)-related clinical symptoms among male intravenous drug users and homosexual men stratified by HIV serostatus and CD4 cell levels. METHODS: A cross-sectional sample using concurrent longitudinal studies of the natural history of HIV-1 infection among intravenous drug users (N = 539) and homosexual men (N = 932) was recruited in Baltimore, Md. Participants were administered a risk behavior interview and physical examination, and had hematologic tests evaluated in a similar calendar period. RESULTS: Both risk groups demonstrated an inverse relationship between frequency of symptoms and CD4 cell count. Fever, night sweats, and lymphadenopathy were not evaluated because pilot data suggested a confounding association with drug injection. Among those with mild to moderate immune suppression, intravenous drug users were significantly more likely than homosexual men to experience fatigue, weight loss, diarrhea, and shortness of breath; to have oral candidiasis, palpable spleen, and lower mean weight on physical examination; and abnormal hematocrit, platelets, and total lymphocyte counts. However, participants in either risk group with CD4 cell levels below 0.2 x 10(9)/L experienced similar frequency of all clinical symptoms. Self-reported oral candidiasis increased fourfold with HIV infection and was as likely in both groups at all CD4 cell levels. Duration and recency of intravenous drug use was not significantly associated with the higher frequency of most clinical symptoms. CONCLUSION: Social factors are an important consideration in evaluating the association between clinical symptoms and HIV immunosuppression. Except for oral candidiasis, there are limitations for the use of clinical symptoms as intermediate outcome measures for HIV infection among intravenous drug users.

Adult↗

Differences in risk factors for human immunodeficiency virus type 1 seroconversion among male and female intravenous drug users.

To examine sex-specific risk factors for human immunodeficiency virus (HIV) type 1 seroconversion among intravenous drug users, the authors conducted a nested case-control study in Baltimore, Maryland, from 1988 to 1992 comparing 146 seroconverters and 539 HIV seronegative controls. Controls were matched on sex, race, date of study entry, and duration of follow-up. Risk factor data were obtained from interviews conducted at the first seroconversion visit for the case and the closest visit for the corresponding seronegative control. Since test results were not available until several weeks after interview, both interviewers and participants were unaware of seroconversion status at the time of interview. When data were analyzed using conditional logistic regression techniques, the variables which were significantly associated with seroconversion among male intravenous drug users included age less than 35 years, a sexually transmitted disease within the past 6 months, lifetime history of syphilis, and current intravenous drug use with an abscess at the injection site. Among women, only a history of three or more sex partners was positively associated with seroconversion and having a biological child under age 18 years was inversely associated with HIV seroconversion. Although the small sample size may have limited the ability to ascertain differences in risks of seroconversion among males and females, these data suggest that sexual transmission contributes to HIV infection among intravenous drug users, especially women.

Adult↗

Changes in T-lymphocyte subsets in intravenous drug users with HIV-1 infection.

OBJECTIVE: To evaluate changes in T-cell subsets in prevalent human immunodeficiency virus type 1 (HIV-1) seronegative and seropositive intravenous drug users (IVDUs) and in HIV-1 seropositive IVDUs with known time of seroconversion. DESIGN: Cohort study with a median 18-month follow-up. SETTING: Community-based clinic established to study the natural history of HIV infection in IVDUs. SUBJECTS: Eight hundred fifty-nine self-referred IVDUs aged 18 through 49 years who injected drugs within the last 10 years and who did not have an AIDS (acquired immunodeficiency syndrome)--defining illness; 152 were seronegative for HIV-1, 621 were seropositive, and 86 seroconverted during the study. OUTCOME MEASURES: Proportions and absolute numbers of lymphocytes and CD3, CD4, and CD8 T cells as determined at 6-month intervals by flow cytometry and complete blood cell counts with automated differential. RESULTS: Median numbers of CD4 lymphocytes at enrollment were 1061/microL (1.06 x 10(9)/L) for seronegative IVDUs, 508/microL for seropositive IVDUs, and 733/microL for those who seroconverted (enrolled a median of 4.5 months after seroconversion); the corresponding figures for CD8 lymphocytes were 628, 894, and 889/microL, respectively. Median rates of decline in absolute numbers and percentages of CD4 lymphocytes per 6 months were 7.6/microL (0.0%) for seropositive IVDUs and 55.1/microL (1.9%) for IVDUs who seroconverted (median follow-up after seroconversion was 12 months). Multivariate regression analysis that incorporated the within-individual correlation of the CD4 lymphocyte counts showed no significant change in these cells over time and no change due to use of drugs. CONCLUSION: Our data suggest that progression of HIV-1 infection in IVDUs, as reflected in decline of CD4 cell counts, is no more rapid than that reported for other risk groups.

Adult↗

Hemodynamic effects of primary closure versus patch angioplasty of the carotid artery.

This study evaluated the hemodynamic changes associated with patch angioplasty compared to primary closure of the canine carotid artery. A standard arteriotomy was closed either primarily, with a 5x28 mm expanded polytetrafluoroethylene (ePTFE) patch, or with a 10x28 mm ePTFE patch. Measurements for the primary closure group showed a systolic pressure gradient of 17 mmHg across the closure and a peak systolic velocity increase of 58% at mid-closure compared to proximal inflows. Flow turbulence increased at mid-closure in the 10 mm patch group, with the percent spectral window lowered from 0.50 to 0.36. These data show that primary vessel closure creates a mild local stenosis with flow acceleration but no flow turbulence. No significant hemodynamic disturbances are caused by a moderate sized patch; however, a large patch relative to native vessel dimensions creates marked flow disturbances throughout the cardiac cycle. As turbulence and flow separation are felt to contribute to restenosis, care should be taken in the selection of patch size when used following carotid endarterectomy.

Angioplasty↗

Focal myocardial injury following blunt chest trauma: a comparison of indium-111 antimyosin scintigraphy with other noninvasive methods.

The diagnosis of myocardial contusion is often difficult, as traditional methods such as serial electrocardiograms, cardiac enzyme (creatine kinase [CK-MB]) analysis, and echocardiography lack sensitivity and specificity. Recent reports have shown that 111In labelled antimyosin scanning has high sensitivity for detecting cardiac injury. However, no prior studies have been reported for antimyosin imaging with patients suspected of sustaining a cardiac contusion. Accordingly, 17 patients with severe multisystem trauma (intrathoracic vascular injury in eight patients, pneumothorax and pulmonary contusion in 13) underwent antimyosin scintigraphy, echocardiography, 12-lead electrocardiograms, and CK-MB determinations. Arrhythmias were noted in seven patients, four of whom died. All patients has elevated CK levels but CK-MB isoenzyme was greater than 4% in only three. Abnormal ST segments were noted in nine subjects, only one of whom had CK-MB elevation. Echocardiography revealed pericardial effusions in four patients but was technically suboptimal in 53% of the studies. Blinded interpretation of the antimyosin scans revealed only one with focal myocardial uptake; this same patient had the only discrete wall motion abnormality on the echocardiogram and also had ST depression with ectopy but normal CK-MB. Thus in patients with suspected myocardial contusion, echocardiography is frequently limited technically and the electrocardiogram and CK analysis appear to lack diagnostic accuracy. In contrast, monoclonal antimyosin imaging may be performed in patients with trauma without limitation and yields results that are concordant with echocardiograms. In patients with suspected myocardial contusion, focal antimyosin uptake is uncommon despite severe thoracic injury, which suggests that extensive myocardial necrosis is not the primary method of injury.

Adult↗

Narcotic-induced suppression of natural killer cell activity in ventilated and nonventilated rats.

Surgical stress and general anesthesia can suppress immune function and thus may increase postsurgical infections and tumor metastasis. We previously reported that two narcotics commonly used in high-dose opiate anesthesia (fentanyl and sufentanil) suppress natural killer (NK) cell activity in rats. Such doses of narcotics also cause respiratory depression accompanied by hypoxia, hypercarbia, and acidosis, which might account for the observed narcotic-induced NK suppression. In the present study, we compared the effects of fentanyl on NK activity in ventilated and non-ventilated rats. Fentanyl significantly suppressed NK cell activity to the same magnitude in the two groups, although the groups significantly differed in CO2 and O2 levels. The fact that high-dose fentanyl-induced NK suppression can be demonstrated in ventilated rats accentuates the relevance of these findings to clinical studies showing NK suppression in the immediate postoperative period. Such immunosuppression could be a risk factor for patients undergoing surgery, especially in cancer-related operations.

Animals↗

Needle-cleaning practices among intravenous drug users who share injection equipment in Baltimore, Maryland.

In Baltimore, Maryland, between 1988 and 1989, 2,921 intravenous drug users were recruited into a study of drug injection practices and human immunodeficiency virus (HIV) infection. Sixty-three percent reported both current use and sharing of needles; almost all these (N = 1,757) reported using injection equipment immediately after it was used by another intravenous drug user. Of the 1,757, 62% said that they "typically" cleaned the used equipment with bleach or alcohol before injecting. These data suggest that information about disinfecting needles has disseminated into this population and identifies several groups to target for interventions.

Adult↗

Immune serum markers and CD4 cell counts in HIV-infected intravenous drug users.

We examined the association of three serum immune markers with CD4 cell counts in a large cohort of i.v. drug users with and without human immunodeficiency virus (HIV) infection. Levels of beta 2-microglobulin and neopterin were significantly elevated in HIV-infected subjects and increased in association with decline in CD4 cell counts (all p less than 0.001). Serum IgA levels in HIV-seropositive individuals were significantly elevated only when the CD4 cell count was less than 200/microliters (p less than 0.001). After controlling for HIV status and CD4 count, recent history of hepatitis was associated with significantly higher beta 2-microglobulin (p = 0.028) and marginally higher neopterin (p = 0.052) levels. There was no association of race, gender, or drug use patterns with levels of serum immune markers after controlling for HIV status and CD4 count. These data indicate that immune activation is coupled with immunosuppression in HIV-infected i.v. drug users. In addition, beta 2-microglobulin and neopterin levels are elevated in persons with a recent history of hepatitis but not in those with recent non-AIDS-defining bacterial infections. Markers of immune activation do not vary by race, gender, or drug use patterns among i.v. drug users.

Biomarkers↗

Prognostic indicators for development of AIDS among intravenous drug users.

A cohort of 544 human immunodeficiency virus-1 (HIV-1) seropositive intravenous drug users (IVDUs) was recruited in 1988 and early 1989; data on laboratory markers, clinical symptoms, intravenous drug use, and demographics were collected. Forty-one IVDUs developed AIDS within 2 years of enrollment. Data were analyzed using methods of survival analysis. None of the individuals reported use of antiviral agents or Pneumocystis carinii prophylaxis at baseline. A very strong (p less than 0.001) dose-response relationship was identified between CD4 cell count at baseline and the subsequent development of AIDS. In multivariate analysis, both the presence of more than one clinical HIV-1-related symptom and serum neopterin greater than 12 nmol/L showed significant associations with the relative hazard (95% confidence interval) of AIDS after controlling for CD4 of 2.9 (1.6, 5.6) and 2.0 (1.0, 3.7), respectively. In these IVDUs, serum beta 2-microglobulin did not add predictive power for progression to AIDS. The effect of clinical symptoms was stronger for high CD4 cell counts, indicating the need to monitor HIV seropositive IVDUs with both laboratory studies and clinical evaluation.

Acquired Immunodeficiency Syndrome↗

New evidence on intravenous cocaine use and the risk of infection with human immunodeficiency virus type 1.

To examine whether recent intravenous use of cocaine might be associated with increased risk of human immunodeficiency virus type 1 (HIV) infection, the authors studied 2,597 active intravenous drug users: 2,399 with recent cocaine injection and 198 with recent injection of heroin or other drugs but not cocaine. These subjects were adult residents of Baltimore City and the surrounding Maryland counties, recruited via outreach into the community between February 1988 and March 1989. In contrast to the first report on the cocaine-HIV association, the present study sample was not recruited solely from drug treatment programs. In the present study, estimated HIV seroprevalence was 26.4% for recent cocaine injectors as compared with 10.6% among all other recent intravenous drug users; the relative odds estimate was 3.03. In the untreated segment of the sample, HIV seroprevalence was 26.0% for recent cocaine injectors as compared with 8.9% among others (relative odds (RO) = 3.61). The estimated degree of association did not change appreciably when multiple logistic regression was used to hold constant potentially confounding and/or mediating variables such as receptive anal intercourse, number of sex partners, and use of injection equipment obtained at shooting galleries (RO = 2.64). Augmenting these cross-sectional data, preliminary prospective data showed excess risk of HIV seroconversion among recent cocaine injectors (estimated relative risk = 2.11). While other research has examined the cocaine-HIV association, the present study differs in that it has allowed a test for whether the association was a spurious artifact of studying drug users recruited solely from drug treatment programs, a broad array of alternative determinants of HIV infection have been held constant, and the association has been examined with seroconversion data. The results lend support to the abiding concern about the risk of HIV infection among cocaine users.

Adolescent↗

Antibody to hepatitis C virus among cardiac surgery patients, homosexual men, and intravenous drug users in Baltimore, Maryland.

In order to define the risk factors for infection with hepatitis C virus, the authors determined the prevalence and incidence of antibodies to hepatitis C in three cohorts in Baltimore, Maryland, enrolled in prospective studies of human immunodeficiency virus (HIV-1) infection. Among 500 multi-transfused patients who underwent cardiac surgery in 1985 and 1986, 12 (2.4%) were hepatitis C seropositive before surgery while 19 (3.9%) developed antibodies in the 8-12 months after surgery. The seroprevalence of hepatitis C virus among 225 intravenous drug users followed since 1988 was 85%, which did not vary by HIV-1 status. Longer duration of intravenous drug use was significantly associated with hepatitis C seropositivity. Among 926 homosexual/bisexual men followed since 1984, 15 (1.6%) were hepatitis C seropositive; only intravenous drug use and a history of hepatitis A were marginally associated with hepatitis C in this population. No association was found between hepatitis C virus and HIV-1 or sexual behavior variables in this population. These data suggest that hepatitis C is readily transmitted by blood exposure, but is transmitted inefficiently by sexual means.

Adult↗

Smallest region of overlap in Wilms tumor deletions uniquely implicates an 11p13 zinc finger gene as the disease locus.

The development of Wilms tumor (WT) has been associated with the inactivation of a "tumor suppressor" locus in human chromosome 11 band p13. Several WTs that exhibit homozygous deletions of an 11p13 candidate WT gene in its entirety have been reported. We report here a partial deletion of the candidate gene which, upon comparison with other documented homozygous deletions, permitted a precise definition of the critical genomic target in Wilms tumor. The smallest region of overlap between these deletions is a 16-kb segment of DNA encompassing the 5' exon(s) of an 11p13 gene coding for a zinc finger protein, together with an associated CpG island. This finding supports the notion that the candidate gene in question corresponds to the 11p13 WT1 Wilms tumor locus.

Child, Preschool↗