The local safety net, health insurance, preventable hospitalizations and costs: Harris County (Houston), Texas

The aim of this study was to examine the association between determinants of access to healthcare and preventable hospitalizations, based on Davidson et al.'s framework for evaluating the effects of individual and community determinants on access to healthcare. The study population consisted of the low income, non-elderly, hospitalized adults residing in Harris County, Texas in 2004. The objectives of this study were to examine the proportion of the variance in preventable hospitalizations at the ZIP-code level, to analyze the association between the proximity to the nearest safety net clinic and preventable hospitalizations, to examine how the safety net capacity relates to preventable hospitalizations, to compare the relative strength of the associations of health insurance and the proximity to the nearest safety net clinic with preventable hospitalizations, and to estimate and compare the costs of preventable hospitalizations in Harris County with the average cost in the literature. The data were collected from Texas Health Care Information Collection (2004), Census 2000, and Project Safety Net (2004). A total of 61,841 eligible individuals were included in the final data analysis. A random-intercept multi-level model was constructed with two different levels of data: the individual level and the ZIP-code level. The results of this study suggest that ZIP-code characteristics explain about two percent of the variance in preventable hospitalizations and safety net capacity was marginally significantly associated with preventable hospitalizations (p= 0.062). Proximity to the nearest safety net clinic was not related to preventable hospitalizations; however, health insurance was significantly associated with a decreased risk of preventable hospitalization. The average direct cost was $6,466 per preventable hospitalization, which is significantly different from reports in the literature. ^

Club drug use and unprotected anal intercourse among HIV-seronegative men who have sex with men seeking HIV/STD testing at a local STD clinic in Houston

Objective. To explore (1) the association between "club drug" use and unprotected anal intercourse (UAI) and (2) the association between binge drug use and UAI among HIV seronegative men who have sex with men (MSM) seeking HIV/STD testing at a local clinic in Houston. ^ Study design. A sub-sample of 297 HIV seronegative MSM from a cross-sectional study of drug and sexual behavior in Houston was conducted in 2006. Patients who were seeking HIV/STD testing at a local MSM-identified STD clinic were recruited for an anonymous computer-assisted interview. Analysis of identified secondary data consisted of self-reported information about demographic characteristics, use of drugs, and sexual behaviors. ^ Results. With new and casual sex partners, there was a strong and statistically significant association between use of "club drugs" and UAI. No association between binge drug use and UAI was evident. Men aware of HIV seropositivity or unaware of the HIV serostatus of their primary partner were less likely to report UAI. ^ Conclusion. These data suggest that in the Houston area, HIV-negative MSM club drug users, particularly multiple drug users, are at higher risk of UAI than comparable MSMs who do not use club drugs. Episode-level data regarding binge use of these and other drugs, and UAI should be collected in future studies to explore their relationship. The 'new partner' category should be added to sex partner types to measure sex and drug use behaviors in future studies.^ Keywords. HIV-negative MSM; club drugs; unprotected anal intercourse; binge drug use. ^

Suspected outbreak of dengue fever in Houston: Clinical characteristics and determination of autochthonous transmission between 2003 and 2005

Houston, Texas maintains the appropriate climate and mosquito populations to support the circulation of dengue viruses. The city is susceptible to the introduction and subsequent local transmission of dengue virus with its proximity to dengue-endemic Mexico and the high degree of international travel routed through its airports. In 2008, a study at the University of Texas School of Public Health identified 58 suspected dengue fever cases that presented at hospitals and clinics in the Houston area. Serum or CSF samples of the 58 samples tested positive or equivocal for the presence of anti-dengue IgM antibodies (Rodriguez, 2008). Here, we present the results of an investigation aimed to describe the clinical characteristics of the 58 suspected dengue fever cases and to determine if local transmission had occurred. Data from medical record abstractions and personal telephone interviews were used to describe clinical characteristics and travel history of the suspected cases. Our analysis classified six probable dengue fever cases based on the case definition from the World Health Organization. Three of the probable cases for which we were able to obtain travel history had not recently traveled to an endemic area prior to onset of symptoms suggesting the illnesses were locally acquired in Houston. Further analysis led us to hypothesize that additional cases of dengue fever are present in our study population. Fifty-one percent of the study population was diagnosed with meningitis and/or encephalitis. Sixty percent of the individuals who received a lumbar puncture had abnormal CSF. Together these findings indicate viral infection with neurological involvement, which has been reported to occur with dengue fever. Among the individuals who received liver enzyme analysis, 54% had evidence of abnormal liver enzyme levels, a clinical sign commonly observed with dengue. Our results indicate that a suspected outbreak of dengue fever with autochthonous transmission occurred in the Houston area between 2003 and 2005. ^

Immunologic characteristics of immunogenic variants generated by {\it in vitro\/} treatment of a methylcholanthrene-induced murine fibrosarcoma MCA-F with 1 methyl-3-nitro-1-nitrosoguanidine, 5 -aza-2$\sp\prime$-deoxycytidine, or ultraviolet radiation

This study addresses the questions of whether the frequency of generation and in vivo cross-reactivity of highly immunogenic tumor clones induced in a single parental murine fibrosarcoma cell line MCA-F is more closely related to the agent used to induce the Imm$\sp{+}$ clone or whether these characteristics are independent of the agents used. These questions were addressed by treating the parental tumor cell line MCA-F with UV-B radiation (UV-B), 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), or 5-aza-2$\sp\prime$-deoxycytidine (5-azaCdR). The frequency of Imm$\sp{+}$ variant generation was similarly high for the three different agents, suggesting that the frequency of Imm$\sp{+}$ generation was related more closely to the cell line than to the inducing agent used. Cross-reactivity was tested with two Imm$\sp{+}$ clones from each treatment group in a modified immunoprotection assay that selectively engendered antivariant, but not antiparental immunity. Under these conditions each clone, except one, immunized against itself. The MNNG-induced clones engendered stronger antivariant immunity but a weaker variant cross-reactive immunity could also be detected.^ This study also characterized the lymphocyte populations responsible for antivariant and antiparental immunity in vivo. Using the local adoptive transfer assay (LATA) and antibody plus complement depletion of T-cell subsets, we showed that immunity induced by the Imm$\sp{+}$ variants against the parent MCA-F was transferred by the Thy1.2$\sp{+}$, L3T4a$\sp{+}$, Lyt2.1$\sp{-}$ (CD4$\sp{+}$) population, without an apparent contribution by Thy1.2$\sp{+}$, L3T4a$\sp{-}$, Lyt2.1$\sp{+}$ (CD8$\sp{+}$) cells. A role for Lyt2.1$\sp{+}$T lymphocytes in antivariant, but not antiparent immunity was supported by the results of LATA and CTL assays. Immunization with low numbers of viable Imm$\sp{+}$ cells, or with high numbers of non viable Imm$\sp{+}$ cells engendered only antivariant immunity without parental cross-protection. The associative recognition of parental antigens and variant neoantigens resulting in strong antiparent immunity was investigated using somatic cells hybrids of Imm$\sp{+}$ variants of MCA-F and an antigenically distinct tumor MCA-D. An unexpected result of these latter experiments was the expression of a unique tumor-specific antigen by the hybrid cells. These studies demonstrate that the parental tumor-specific antigen and the variant neoantigen must be coexpressed on the cell surface to engender parental cross-protective immunity. (Abstract shortened with permission of author.) ^