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Recruitment of community participants for clinical research studies is a challenging task. When possible, community-based recruitment efforts should involve members of the targeted community in the planning, community preparation, and actual recruitment process. It becomes even more difficult to recruit study participants from the community when the research involves an invasive procedure, or when diverse target groups require that a variety of recruitment methods be used. The Community Health and Stress Evaluation (CHASE) Study was designed to determine the role of psychosocial and biobehavioral factors in the etiology of coronary heart disease. It involved both an invasive medical procedure (a spinal tap) and the collection of survey and medical information from Black and White persons in different socioeconomic status (SES) groups. Interestingly, we experienced the greatest difficulty in recruiting lower SES white persons, while groups that typically are 'difficult to find' (such as Blacks) were actually easiest to recruit for the study. This paper describes the background of the CHASE study, the community recruitment methods used, and the results of the recruitment efforts by race, gender and SES gradient. We present an evaluation of the community recruitment component, why we think differences occurred, and the lessons learned from the experiences that may be applied to similar studies. [ABSTRACT FROM AUTHOR]

The importance of gut commensal bacteria in maintaining immune homeostasis is increasingly understood. We recently described that alteration of the gut microflora can affect a population of Foxp3(+)T(reg) cells that regulate demyelination in experimental autoimmune encephalomyelitis (EAE), the experimental model of human multiple sclerosis. We now extend our previous observations on the role of commensal bacteria in CNS demyelination, and we demonstrate that Bacteroides fragilis producing a bacterial capsular polysaccharide Ag can protect against EAE. Recolonization with wild type B. fragilis maintained resistance to EAE, whereas reconstitution with polysaccharide A-deficient B. fragilis restored EAE susceptibility. Enhanced numbers of Foxp3(+)T(reg) cells in the cervical lymph nodes were observed after intestinal recolonization with either strain of B. fragilis. Ex vivo, CD4(+)T cells obtained from mice reconstituted with wild type B. fragilis had significantly enhanced rates of conversion into IL-10-producing Foxp3(+)T(reg) cells and offered greater protection against disease. Our results suggest an important role for commensal bacterial Ags, in particular B. fragilis expressing polysaccharide A, in protecting against CNS demyelination in EAE and perhaps human multiple sclerosis.

Mucosal tolerance has been considered a potentially important pathway for the treatment of autoimmune disease, including human multiple sclerosis and experimental conditions such as experimental autoimmune encephalomyelitis (EAE). There is limited information on the capacity of commensal gut bacteria to induce and maintain peripheral immune tolerance. Inbred SJL and C57BL/6 mice were treated orally with a broad spectrum of antibiotics to reduce gut microflora. Reduction of gut commensal bacteria impaired the development of EAE. Intraperitoneal antibiotic-treated mice showed no significant decline in the gut microflora and developed EAE similar to untreated mice, suggesting that reduction in disease activity was related to alterations in the gut bacterial population. Protection was associated with a reduction of proinflammatory cytokines and increases in IL-10 and IL-13. Adoptive transfer of low numbers of IL-10-producing CD25(+)CD4(+) T cells (>75% FoxP3(+)) purified from cervical lymph nodes of commensal bacteria reduced mice and in vivo neutralization of CD25(+) cells suggested the role of regulatory T cells maintaining peripheral immune homeostasis. Our data demonstrate that antibiotic modification of gut commensal bacteria can modulate peripheral immune tolerance that can protect against EAE. This approach may offer a new therapeutic paradigm in the treatment of multiple sclerosis and perhaps other autoimmune conditions.

The immunity-related GTPases (IRG), also known as p47 GTPases, are a family of proteins that are tightly regulated by IFNs at the transcriptional level and serve as key mediators of IFN-regulated resistance to intracellular bacteria and protozoa. Among the IRG proteins, loss of Irgm1 has the most profound impact on IFN-gamma-induced host resistance at the physiological level. Surprisingly, the losses of host resistance seen in the absence of Irgm1 are sometimes more striking than those seen in the absence of IFN-gamma. In the current work, we address the underlying mechanism. We find that in several contexts, another protein in the IRG family, Irgm3, functions to counter the effects of Irgm1. By creating mice that lack Irgm1 and Irgm3, we show that several phenotypes important to host resistance that are caused by Irgm1 deficiency are reversed by coincident Irgm3 deficiency; these include resistance to Salmonella typhimurium in vivo, the ability to affect IFN-gamma-induced Salmonella killing in isolated macrophages, and the ability to regulate macrophage adhesion and motility in vitro. Other phenotypes that are caused by Irgm1 deficiency, including susceptibility to Toxoplasma gondii and the regulation of GKS IRG protein expression and localization, are not reversed but exacerbated when Irgm3 is also absent. These data suggest that members of the Irgm subfamily within the larger IRG family possess activities that can be opposing or cooperative depending on the context, and it is the balance of these activities that is pivotal in mediating IFN-gamma-regulated host resistance.

Ischemic stroke from a reduction in blood flow to the brain microvasculature results in a subsequent decreased delivery of oxygen (i.e., hypoxia) and vital nutrients to endothelial, neuronal, and glial cells. Hypoxia associated with stroke has been shown to increase paracellular permeability of the blood-brain barrier, leading to the release of cellular mediators and brain tissue injury. Whereas reperfusion does not occur in all ischemic strokes, increased permeability has been seen in posthypoxic reoxygenation. Currently, it is unknown whether these deleterious effects result from cellular mechanisms stimulated by decreased oxygen during stroke or posthypoxic reoxygenation stress. This study used primary bovine brain microvessel endothelial cells (BBMECs) to examine the involvement of nitric oxide (NO) as a mediator in hypoxia-induced permeability changes. Hypoxia-induced increased transport of [14C]sucrose across BBMEC monolayers compared with normoxia was attenuated by either posthypoxic reoxygenation or inhibition of NO synthase (NOS). The hypoxia-induced permeability effect was further reduced when NOS inhibition was combined with posthypoxic reoxygenation. Additionally, a significant increase in total NO was seen in BBMECs after hypoxic exposure. This correlation was supported by the increased [14C]sucrose permeability observed when BBMECs were exposed to the NO donor diethylenetriaamine NONOate. Western blot analyses of NOS isoforms showed a significant increase in the inducible isoform after hypoxic exposure with a subsequent reduction in expression on reoxygenation. Results from this study suggest that hypoxia-induced blood-brain barrier breakdown can be diminished by inhibition of NO synthesis, decreased concentration of NO metabolites, and/or reoxygenation.

This study examined differences in contextual factors, substance use, sexual risk behaviors, and comorbid histories between African-American, out-of-treatment, crack-abusing women who had either a single sexual partner or multiple partners. Bivariate analysis indicated that women with multiple partners were more likely than women with a single partner to be homeless, financially dependent, and to have histories of sexual, physical, and emotional abuse. Women with multiple partners reported higher levels of depression, anxiety, and more symptoms of posttraumatic stress disorder (PTSD). In multiple logistic regression analysis, being unemployed, difficult childhood, and number of days of crack use in the previous 30 days, longer crack runs, and more frequent unprotected fellatio were associated with increased odds of having multiple sexual partners. Being married or living as married was associated with decreased odds of having multiple sexual partners. The importance of assessing contextual and historical factors and implications for future research is discussed.

Co-culture with glial cells and glia-conditioned media can induce blood-brain barrier properties in microvessel endothelial cells and protect against hypoxia-induced blood-brain barrier breakdown. We examined the effect of two types of glia-conditioned media on brain microvessel endothelial cell permeability and tight junction protein expression, and studied potential mechanisms of action. We found that C6-glioma-conditioned media, but not rat astrocyte-conditioned media, protected against an increase in permeability induced by exposure to 1% oxygen for 24 hours. This hypoxic stress caused an increase in the expression of tight junction proteins claudin-1 and actin, particularly in cells treated with C6-conditioned media. We found that C6-conditioned media has a significantly higher level of both basic fibroblast growth factor and vascular endothelial growth factor. Treatment with C6-conditioned media for 1 or 3 days protects against hypoxia-induced permeability increases, and this protective effect may be mediated by signal transduction pathways terminating at the transcription factor NFkappaB.