Publications by authors named "Ananaba G"

Nitrergic neurons of the dorsal raphe nucleus (DRN) may play a role in physiological stress responses. The caudal lateral wings (CLW) are unique compared to other rostral-caudal DRN sub-regions because they contain distinct nitric oxide (NO) synthase (NOS) populations that are independent of tryptophan hydroxylase (TPH). NOS neurons in the CLW are also highly activated during acute restraint stress.

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Vitamin D hormone (1,25-dihydroxyvitamin D) is involved in innate immunity and induces host defense peptides in epithelial cells, suggesting its involvement in mucosal defense against infections. Chlamydia trachomatis is a major cause of bacterial sexually transmitted disease worldwide. We tested the hypothesis that the vitamin D endocrine system would attenuate chlamydial infection.

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Background: To date there has not been any nationwide age-standardized incidence data reported for prostate cancer in Nigeria. We examined and integrated diverse trends in the age-specific incidence of prostate cancer into a comprehensive trend for Nigeria, and examined how best the existing data could generate a countrywide age-standardized incidence rate for the disease.

Methods: Data were obtained from studies undertaken between 1970 and 2007 in referral hospital-based cancer registries.

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Background: The purpose of our study was to show the distinction between the apoptotic and anti-proliferative signaling of phytosterols and cholesterol-enrichment in prostate cancer cell lines, mediated by the differential transcription of caveolin-1, and N-myc downstream-regulated gene 1 (NDRG1), a pro-apoptotic androgen-regulated tumor suppressor.

Methods: PC-3 and DU145 cells were treated with sterols (cholesterol and phytosterols) for 72h, followed by trypan blue dye-exclusion measurement of necrosis and cell growth measured with a Coulter counter. Sterol induction of cell growth-suppressor gene expression was evaluated by mRNA transcription using RT-PCR, while cell cycle analysis was performed by FACS analysis.

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The search for a classic biomarker for prostate cancer has been on for a very long time, and it is still elusive. Despite the extensive and prolonged use of the prostate-specific antigen (PSA) as a screening tool for prostate cancer, many clinicians still identify its limitations in the grading of tumors, and monitoring of response to treatment. These limitations are based on the concealment of cancer by low levels of PSA, and over diagnosis and over treatment that are resultant of excessively high levels of antigens.

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Vaccines are needed to prevent the oculogenital diseases of Chlamydia trachomatis. Infected hosts develop immunity, although temporary, and experimental vaccines have yielded significant protective immunity in animal models, fueling the impetus for a vaccine. Because infections cause sequelae, the functional relationship between infection- and vaccine-induced immunity is unclear.

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Background: The purpose of our study was to show the apoptotic and anti-proliferative effects of phytosterols as distinct from cholesterol effects on prostate cancer cell lines, and also their differential expression of caveolin-1, and a prostate specific gene, PCGEM1.

Methods: PC-3 and DU145 cells were treated with sterols (cholesterol and phytosterols) for 48h, followed by trypan blue dye exclusion measurement of cytotoxicity and MTT cell proliferation assays, respectively. Cell cycle analysis was carried out microscopically, and by propidium iodide uptake using flow cytometry.

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The Vibrio cholerae ghost (rVCG) platform is an effective carrier and delivery system for designing efficacious Chlamydia vaccines. We investigated whether CTA2B, the nontoxic derivative of cholera toxin, can augment protective immunity conferred by an rVCG-based chlamydial vaccine and enhance cross-protection against heterologous chlamydial strains. An rVCG vaccine coexpressing chlamydial major outer membrane protein and CTA2B was genetically constructed and antigens were targeted to the inner membrane of V.

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We investigated the hypothesis that the enhanced Ag-presenting function of IL-10-deficient dendritic cells (DCs) is related to specific immunoregulatory cytoskeletal molecules expressed when exposed to Ags. We analyzed the role of a prominent cytoskeletal protein, LEK1, in the immunoregulation of DC functions; specifically cytokine secretion, costimulatory molecule expression, and T cell activation against Chlamydia. Targeted knockdown of LEK1 expression using specific antisense oligonucleotides resulted in the rapid maturation of Chlamydia-exposed DCs as measured by FACS analysis of key activation markers (i.

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Background And Purpose: Genital infections due to Chlamydia trachomatis pose a considerable public health challenge worldwide and a vaccine is urgently needed to protect against these infections. We examined whether a vaccine composed of a combination of the major outer membrane protein (MOMP) and porin B protein (PorB) of C. trachomatis would have a protective advantage over a single subunit construct.

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Effective delivery systems are needed to design efficacious vaccines against the obligate intracellular bacterial pathogen, Chlamydia trachomatis. Potentially effective delivery vehicles should promote the induction of adequate levels of mucosal T-cell and antibody responses that mediate long-term protective immunity. Antigen targeting to the nasal-associated lymphoid tissue (NALT) is effective for inducing high levels of specific immune effectors in the genital mucosa, and therefore suitable for vaccine delivery against genital chlamydial infection.

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T cell immunity protects against diseases caused by the obligate intracellular bacterium Chlamydia trachomatis. Incidentally, host inflammatory response that includes T cells appears to also contribute to the pathogenesis of chlamydial diseases such as trachoma and tubal factor infertility (TFI). Therefore, designing effective prevention strategies requires a delineation of immune processes responsible for pathology and those mediating immunity, and identification of the immunogenetic factors predisposing to complication development.

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Identification and targeting of novel immunobiological factors that regulate the induction of Th1 cells are crucial for designing effective vaccines against certain intracellular pathogens, including Chlamydia. IL-10-deficient dendritic cells (DC) are potent APCs and effective cellular vaccines that activate a high frequency of specific Th1 cells. To elucidate the molecular basis for the potency of the IL-10-deficient APC system, we tested the hypothesis that Chlamydia Ag-primed IL-10 knockout (IL-10KO) DC are quantitatively and qualitatively distinct in their metabolic characteristics relating to T cell activation.

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The administration of an efficacious vaccine is the most effective long-term measure to control the oculogenital infections caused by Chlamydia trachomatis in humans. Chlamydia genome sequencing has identified a number of potential vaccine candidates, and the current challenge is to develop an effective delivery vehicle for induction of a high level of mucosal T and complementary B cell responses. Vibrio cholerae ghosts (VCG) are nontoxic, effective delivery vehicles with potent adjuvant properties, and are capable of inducing both T cell and Ab responses in mucosal tissues.

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Immunity to intracellular microbial pathogens, including Chlamydia species, is controlled primarily by cell-mediated effector mechanisms, yet, the absence of antibodies results in inefficient microbial clearance. We investigated the hypothesis that certain Fc receptor functions promote the rapid induction of elevated T helper type 1 (Th1) response, which effectively clears chlamydiae. FcR(-/-) mice exhibited a delayed and reduced frequency of Chlamydia-specific Th1 cells, compared to FcR(+/+) mice.

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An efficacious vaccine is needed to control the morbidity and burden of rising healthcare costs associated with genital Chlamydia trachomatis infection. Despite considerable efforts, the development of reliable chlamydial vaccines using conventional strategies has proven to be elusive. The 40kDa major outer membrane protein (MOMP) of C.

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The prevailing paradigm for designing potentially efficacious vaccines against the obligate intracellular bacterium, Chlamydia trachomatis, advocates regimens capable of inducing a mucosal antigen-specific T helper type 1 (Th1) response. However, recent reports indicate that rapid and efficient clearance of a secondary infection also requires certain B-cell functions. We investigated the hypothesis that Fc receptor (FcR)-mediated antibody effector mechanisms are important B-cell-related functions involved in controlling a chlamydial genital reinfection.

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Current design strategies for vaccines against certain microbial pathogens, including Chlamydia trachomatis, require the induction and targeting of specific immune effectors to the local sites of infection known as the mucosal effector sites. Chemokines and their receptors are important mediators of leukocyte trafficking and of the controlled recruitment of specific leukocyte clonotypes during host defense against infections and during inflammation. We analyzed the dynamics of chemokine and chemokine receptor expression in genital mucosae during genital chlamydial infection in a murine model to determine how these molecular entities influence the development of immunity and the clearance of infection.

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A new paradigm for designing vaccines against certain microbial pathogens, including Chlamydia trachomatis, is based on the induction of local mucosal Th1 response. IL-10 is an anti-inflammatory cytokine that exerts negative immunoregulatory influence on Th1 response. This study investigated whether biochemical modulation of endogenous IL-10 expression at the level of APCs is a practical strategy for enhancing the specific Th1 response against pathogens controlled by Th1 immunity.

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Recent studies in animal models of genital chlamydial disease revealed that early recruitment of dendritic cells and specific T helper type-1 (Th1) cells into the genital mucosae is crucial for reducing the severity of the acute phase of a cervico-vaginal infection and arresting ascending disease. These immune effectors are therefore important for preventing major complications of genital chlamydial infection. Other in vitro studies showed that intercellular adhesion molecule-1 (ICAM-1) plays a role in the antichlamydial action of specific CD4+ and CD8+ T cells.

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The antimicrobial activity of T cell-derived cytokines, especially interferon (IFN)-gamma, against intracellular pathogens, such as Chlamydia trachomatis, involves the induction of 3 major biochemical processes: tryptophan catabolism, nitric oxide (NO) induction and intracellular iron (Fe) deprivation. Since the epithelial cell is the natural target of chlamydial infection, the presence of these antimicrobial systems in the cell would suggest that they may be involved in T cell control of intracellular multiplication of Chlamydia. However, the controversy over whether these 3 antimicrobial processes are present in both mice and humans has precluded the assessment of the relative contribution of each of the 3 mechanisms to chlamydial inhibition in the same epithelial cell from either mice or humans.

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The induction of local T helper type 1 (Th1)-mediated cellular immunity is crucial for resistance of mice to genital infection by the obligate intracellular bacterium Chlamydia trachomatis. We tested the hypothesis that the route of immunization that elicits relatively high numbers of chlamydia-specific, gamma interferon (IFN-gamma)-secreting T lymphocytes (ISTLs) in the genital tract would induce optimal protective immunity against reinfection. Female BALB/c mice were infected intravaginally (i.

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Type 1 CD4+-T-cell-mediated immunity is crucial for the resolution of chlamydial infection of the murine female genital tract. Previous studies demonstrating a correlation between CD4+-T-cell-mediated inhibition of chlamydial growth and gamma interferon (IFN-gamma)-mediated induction of nitric oxide synthase suggested a potential role for the nitric oxide (NO) effector pathway in the clearance of Chlamydia from genital epithelial cells by the immune system. To clarify the role of this pathway, the growth levels of Chlamydia trachomatis organisms in normal (iNOS+/+) mice and in genetically engineered mice lacking the inducible nitric oxide synthase (iNOS) gene (iNOS-/- mice) were compared.

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A key impediment to developing respiratory syncytial virus (RSV) vaccines is a lack of understanding of enhanced disease that occurred in children who received a formalin-inactivated RSV (FI-RSV) vaccine. Studies in mice have suggested that the FI-RSV vaccine induces a TH2 and live RSV induces a TH1 memory T cell response. In this study, the cytokine mRNA response of peripheral blood mononuclear cells (PBMC) from adults and children with and without previous RSV infection was characterized using a semiquantitative polymerase chain reaction (PCR).

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The clinical and epidemiologic features of respiratory syncytial virus (RSV) infections suggest that RSV-specific antibody may sometimes contribute to the disease process. Recently, it has been demonstrated that virus-specific antibody can enhance RSV infection of macrophagelike cells in vitro. We evaluated the possibility that antibody might also enhance RSV stimulation of the bronchoactive mediator of inflammation leukotriene C-4 (LTC4)in a macrophagelike cell line, U937.

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