Geographic approaches to quantifying the risk environment: drug-related law enforcement and access to syringe exchange programmes

The concept of the "risk environment"--defined as the "space ... [where] factors exogenous to the individual interact to increase the chances of HIV transmission"--draws together the disciplines of public health and geography. Researchers have increasingly turned to geographic methods to quantify dimensions of the risk environment that are both structural and spatial (e.g., local poverty rates). The scientific power of the intersection between public health and geography, however, has yet to be fully mined. In particular, research on the risk environment has rarely applied geographic methods to create neighbourhood-based measures of syringe exchange programmes (SEPs) or of drug-related law enforcement activities, despite the fact that these interventions are widely conceptualized as structural and spatial in nature and are two of the most well-established dimensions of the risk environment. To strengthen research on the risk environment, this paper presents a way of using geographic methods to create neighbourhood-based measures of (1) access to SEP sites and (2) exposure to drug-related arrests, and then applies these methods to one setting (New York City [NYC]). NYC-based results identified substantial cross-neighbourhood variation in SEP site access and in exposure to drug-related arrest rates (even within the subset of neighbourhoods nominally experiencing the same drug-related police strategy). These geographic measures--grounded as they are in conceptualizations of SEPs and drug-related law enforcement strategies--can help develop new arenas of inquiry regarding the impact of these two dimensions of the risk environment on injectors' health, including exploring whether and how neighbourhood-level access to SEP sites and exposure to drug-related arrests shape a range of outcomes among local injectors.     

Surgical bacterial infections and antimicrobial susceptibility patterns at Lilongwe Central Hospital

A cross sectional study was done between October 1999 and February 2000 to determine antimicrobial susceptibility patterns of consecutive bacterial isolates of 102 clinical samples among surgical in-patients at Lilongwe Central Hospital (LCH), Malawi. Antimicrobial susceptibility was determined using comparative disc diffusion techniques. 83 (81.4%) samples were culture positive for bacterial growth while 19 (18.6%) grew nothing. Of the 93 culture positive specimens, Staphylococcus aureus was the predominant organism 43(51.8%) followed by Proteus species 8(9.6%) and E. coli 7(8.4%). Overall, 98.6% of all isolates tested against ciprofloxacin were susceptible, and against gentamicin and flucloxacin were 84.8% and 66.7% respectively. 59.3% of isolates tested against chloramphenicol were resistant. We recommend a review on the use of chloramphenicol as first-line antimicrobial therapy among surgical in-patients at Lilongwe Central Hospital. We also recommend restricted use of antimicrobials so as to minimise development of drug resistance. Periodic susceptibility studies are necessary to guide judicious use of antibiotics.     

Reduced risk of hepatitis B and hepatitis C among injection drug users in the Tacoma syringe exchange program.

OBJECTIVES. This case-control study examined the association between syringe exchange use and hepatitis B and C in injection drug users. METHODS. Case patients included 28 injection drug users with acute hepatitis B and 20 with acute hepatitis C reported to the health department in a sentinel hepatitis surveillance county; control subjects were injection drug users with no markers of exposure to hepatitis B or C (n = 38 and 26, respectively) attending health department services during the same period. Data were abstracted from clinic records. RESULTS. Seventy-five percent of case patients with hepatitis B and 26% of control subjects had never used the exchange; similar proportions were found for the hepatitis C case and control groups. After adjustment for demographic characteristics and duration of injecting drugs, nonuse of the exchange was associated with a sixfold greater risk of hepatitis B (odds ratio [OR] = 5.5; 95% confidence interval [CI] = 1.5, 20.4) and a sevenfold greater risk of hepatitis C (OR = 7.3; 95% CI = 1.6, 32.8). CONCLUSIONS. The results suggest that use of the exchange led to a significant reduction in hepatitis B and hepatitis C in the county and may have also prevented a substantial proportion of human immunodeficiency virus infections in injection drug users.     

The effects of GM-CSF and G-CSF in promoting growth of clonogenic cells in acute myeloblastic leukemia

A small subset of leukemic cells from most patients with acute myeloblastic leukemia (AML) have properties of stem cells and can be assayed by colony formation in agar or methylcellulose. Colony formation generally requires the addition of exogenous growth factors, but the exact factors required are incompletely defined. The AML colony- promoting activities of two recombinant human colony-stimulating factors (GM-CSF and G-CSF) were investigated by using blasts from 48 patients with AML. In nine cases, no colonies formed with either CSF. In seven cases colonies formed only in response to G-CSF and in 11 cases only in response to GM-CSF. In 21 cases colonies formed in response to either GM-CSF or G-CSF, and in 12 of these cases there was an additive effect between the two CSFs in determining maximum colony size. For cases responding to both GM- and G-CSF, the total number of colonies formed in response to the combination of both CSFs was almost always less than additive compared with the number of colonies formed in response to the individual CSFs. Further, the AML-CFU responding to either GM-CSF or G-CSF could not be distinguished by surface markers or by the cytochemical staining pattern of the colonies. These results suggest that there is considerable overlap between the GM-CSF- and G- CSF-responsive AML-CFU subpopulations in most cases. For five of seven cases, the combination of GM-CSF and G-CSF could replace a leukocyte feeder layer in providing maximum growth stimulation. These results indicate that GM-CSF and G-CSF are active growth factors for AML cells and are frequently additive in promoting maximum colony size.     

促红细胞生成素对实验性肾性贫血的作用

促红细胞生成素(erythropoietin,EPO)是由肾细胞分泌的一种糖蛋白激素。从人胚肾细胞中诱导,经生物化学方法分离、提纯得到此品。本试验用5/6肾切除的方法造成大鼠慢性肾衰性(CRF)贫血,研究不同剂量EPO对CRF贫血的作用。结果表明EPO有显著的促进红细胞生成,改善CRF贫血状态,使其接近或达到正常水平,最佳剂量为1000 U/kg,并可预防实验性贫血,对正常鼠未见明显作用。     

What's community got to do with it? Implementation models of syringe exchange programs.

Syringe exchange programs (SEPs) have been shown to be highly effective in reducing HIV transmission among injection drug users (IDUs). Despite this evidence, SEPs have not been implemented in many communities experiencing HIV epidemics among IDUs. We interviewed 17 key informants in nine U.S. cities to identify factors and conditions that facilitated or deterred the adoption of SEPs. Cities were selected to represent diversity in size, geographic location, AIDS incidence rates, and SEP implementation. Key informants included HIV prevention providers, political leaders, community activists, substance use and AIDS researchers, and health department directors. SEPs were established by one or more of three types of implementation models: (a) broad community coalition support, (b) community activist initiative, and (c) top-down decision making by government authorities. In each model, coalition building and community consultation were critical steps for the acceptance and sustainability of SEPs. When others were not prepared to act, community activists spearheaded SEP development, taking risks in the face of opposition, but often lacked the resources to sustain their efforts. Leadership from politicians and public health officials provided needed authority, clout, and access to resources. Researchers and scientific findings lent force and legitimacy to the effort. Rather than adopting adversarial positions, successful SEP implementers worked with or avoided the opposition. Fear of repercussions and lack of leadership were the greatest barriers to implementing SEPs. Communities that successfully implemented SEPs were those with activists willing to push the agenda, public officials willing to exercise leadership, researchers able to present authoritative findings, and proponents who effectively mobilized resources and worked to build community coalitions, using persistent but nonadversarial advocacy.