Publications

Lifestyle modifications are first-line therapy for patients with gastroesophageal reflux disease (GERD). We applied an evidence-based approach to determine the efficacy of lifestyle measures for GERD management. We used PubMed and Ovid to perform a search of the literature published between 1975 and 2004 using the key words heartburn, GERD, smoking, alcohol, obesity, weight loss, caffeine or coffee, citrus, chocolate, spicy food, head of bed elevation, and late-evening meal. Each study was reviewed by 2 reviewers who assigned one of the following ratings: evidence A, randomized clinical trials; evidence B, cohort or case-control studies; evidence C, case reports or flawed clinical trials; evidence D, investigator experience; or evidence E, insufficient information. We screened 2039 studies and identified 100 that were relevant. Only 16 clinical trials examined the impact on GERD (by change in symptoms, esophageal pH variables, or lower esophageal sphincter pressure) of the lifestyle measure. Although there was physiologic evidence that exposure to tobacco, alcohol, chocolate, and high-fat meals decreases lower esophageal sphincter pressure, there was no published evidence of the efficacy of dietary measures. Neither tobacco nor alcohol cessation was associated with improvement in esophageal pH profiles or symptoms (evidence B). Head of bed elevation and left lateral decubitus position improved the overall time that the esophageal pH was less than 4.0 (evidence B). Weight loss improved pH profiles and symptoms (evidence B). Weight loss and head of bed elevation are effective lifestyle interventions for GERD. There is no evidence supporting an improvement in GERD measures after cessation of tobacco, alcohol, or other dietary interventions.

Adaptive immune responses require clonal expansion and differentiation of naive T cells into cytokine-secreting effector cells. After priming via signals through the T cell receptor, naive T helper cells express cytokine mRNA but do not secrete cytokine protein without additional T cell receptor stimulation. Here we show that primed T cells demonstrated phosphorylation of eukaryotic initiation factor 2-alpha (eIF2alpha), a 'collapsed' polysome profile, increased expression of stress-response genes and accumulation of cytoplasmic granules associated with RNA-binding proteins, all features of the integrated stress response. Restimulation of the cells resulted in rapid eIF2alpha dephosphorylation, ribosomal mRNA loading and cytokine secretion. Interference with the function of granule-associated proteins or accumulation of phosphorylated eIF2alpha enhanced release of interleukin 4 during T helper type 2 priming. Therefore, T lymphocytes require components of the integrated stress response to uncouple differentiation from the execution of effector functions.

To defend against external pathogens, metazoan organisms have evolved numerous defenses that generally fall within the innate and adaptive immune responses. Considerable effort continues to focus on developing a vaccine to manipulate the adaptive immune system to protect against or control HIV-1. However, recent advances in our understanding of the innate immune system have revealed that cells have a potent intrinsic antiretroviral defense in the form of APOBEC3G, which is a member of a larger family of cytidine deaminases that are active against HIV-1 and other retroviruses. Insights into how the action of A3G is circumvented by HIV-1 through the action of its Vif protein, and the surprising mechanisms by which A3G is regulated within the cell, offer exciting new opportunities for developing novel anti-HIV-1 therapies that exploit this intrinsic antiretroviral system.

Histamine, signaling via the type 1 receptor (H1R), has been shown to suppress Th2 cytokine production by in vitro cultured T cells. We examined the role of H1R in allergic inflammation in vivo using a murine asthma model. Allergen-stimulated splenic T cells from sensitized H1R-/- mice exhibited enhanced Th2 cytokine production. Despite this Th2 bias, allergen-challenged H1R-/- mice exhibited diminished lung Th2 cytokine mRNA levels, airway inflammation, goblet cell metaplasia, and airway hyperresponsiveness (AHR). Restoration of pulmonary Th2 cytokines in H1R-/- mice by intranasal IL-4 or IL-13 restored inflammatory lung responses and AHR. Further investigation revealed that histamine acts as a T cell chemotactic factor and defective T cell trafficking was responsible for the absence of lung inflammation. Cultured T cells migrated in response to histamine in vitro, but this was ablated by blockade of H1R but not H2R. In vivo, allergen-specific WT but not H1R-/- CD4+ T cells were recruited to the lungs of naive recipients following inhaled allergen challenge. H1R-/- T cells failed to confer airway inflammation or AHR observed after transfer of WT T cells. Our data establish a role for histamine and H1R in promoting the migration of Th2 cells into sites of allergen exposure.