Tumor necrosis factor beta (TNF-ß) NcoI polymorphism is associated with multiple sclerosis in Caucasian patients from Southern Brazil independently from HLA-DRB1.

This study evaluated the association of tumor necrosis factor beta (TNF-ß) NcoI polymorphism with the presence of multiple sclerosis (MS), disability, and HLA-DRB1 alleles in 208 Brazilian MS patients. As controls, 147 healthy individuals were included. The disability was evaluated at baseline and 5-year follow-up using the Expanded Disability Status Scale (EDSS). The TNF-ß genotypes were determined using PCR and restriction fragment length polymorphism and serum TNF-α level was determined using enzyme-linked immunosorbent assay. Among the MS patients, 166 (79.8 %) were white, 39 (18.7 %) were brown, and three (1.4 %) were Asian descents (those were excluded from the further analysis). Among the 205 MS patients, 149 (72.6 %) presented remitting-relapsing MS. The baseline and 5-year follow-up EDSS ranged from 0.0 to 3.0 and from 1.0 to 5.7, respectively. The TNFB2/B2 genotype was associated with the presence of MS among the white patients (p = 0.0443). Brown patients presented higher disability (p = 0.0234) and higher TNF-α levels (p = 0.0463) than white patients. White and brown patients carrying TNFB2/B2 genotype exhibited higher TNF-α levels (p = 0.0354 and p = 0.0309, respectively) than those with other geotypes. Association between TNF-ß NcoI genotypes and HLA-DRB1 alleles was not observed among the MS patients (p > 0.05). Taken together, TNFB2 allele was associated with the presence of MS independently of HLA-DRB1 in white patients and the TNFB2/B2 genotype was associated with increased TNF-α levels in white and brown patients, which could be an important genetic factor candidate for the susceptibility and pathogenesis of MS.

Possible association between TGF-ß1 polymorphism and oral cancer.

Oral squamous cell carcinoma (OSCC) is a worldwide health problem because it is a great cause of cancer morbidity and mortality. The transforming growth factor-ß1 (TGF-ß1) is involved in the regulation of numerous immunomodulatory processes. Thus, the aim of this case-control study was to investigate the possible association between the TGF-ß1T869C polymorphism and oral cancer. The genomic DNA extracted from peripheral blood of 62 male smoker patients diagnosed with OSCC and 62 smokers without cancer was analysed. The C allele was significantly more prevalent in the oral cancer group than in the controls, and individuals carrying this allele had an estimated 2.73-fold greater relative risk of developing cancer compared with C allele noncarriers (OR = 2.73, 95% CI = 1.19-6.28). Although T allele was not statistically significant among the controls, considering the genotypic analysis, the TT homozygous genotype showed a protector effect in relation to oral cavity cancer (OR = 0.37, 95% CI = 0.16-0.84). Some clinicopathological features were also analysed for genotype distribution, and no significant differences were observed: tumour size (P > 0.70), nodal status (P > 0.10) and tumour stage (P > 0.70). This is the first report of a study assessing the importance of T869C TGF-ß polymorphism in oral cancer. It is known that the TGF-ß T869C variation results in a Leu10Pro substitution in the signal peptide sequence. Our results suggested that the C allele could increase TGF-ß secretion which suppresses antitumour immune responses and may affect the OSCC risk.

Caveolin involvement and modulation in breast cancer.

Caveolae are highly enriched in numerous membrane-bound proteins and caveolin-1 is their major component. Caveolae and caveolin proteins are involved in a variety of cellular processes including lipid homeostasis, endocytosis, signal transduction, and tumorigenesis. Breast cancer is one of the most common cancers in women throughout the world. Clinical studies have shown that the correlation of caveolin-1 expression with tumor progression varies with tumor type. The data presented here extend the findings that caveolin-1 suppresses breast cancer but there are controversial studies. The potential function of caveolin-1 in scaffolding signaling factors also demonstrates the importance of its expression control and modulation, correlating with physiological or pathological conditions. Based on current research, this review presents the current understanding of their function and the involvement of caveolin-1 in breast cancer pathogenesis.

Genetic polymorphisms in the chemokine and chemokine receptors: impact on clinical course and therapy of the human immunodeficiency virus type 1 infection (HIV-1).

The natural history and pathogenic processes of infection by the human immunodeficiency virus type 1 (HIV-1) are complex, variable, and dependent upon a multitude of viral and host factors and their interactions. The CCR5-Delta32 allele remains the most important genetic factor known to be associated with host resistance to the HIV-1 infection. However, other mutations in the CCR5, CCR2, CX(3)CR1, CXCL12 (SDF1), and CCL5 (RANTES) genes have been identified and associated with host resistance and/or susceptibility to HIV-1 infection and disease progression. Some studies have also suggested that chemokine receptor gene polymorphisms may affect response to potent antiretroviral therapy. This article reviews the polymorphisms already described in the mutant chemokine receptors or ligands and their impact on the host susceptibility to HIV-1 infection and on the clinical course of the disease, as well as the development of new anti-HIV therapies that takes into account these potential targets in the host. These genetic polymorphisms could be used as genetic markers to detect individuals at higher risk of developing either a faster disease progression or therapeutic failure. Once these individuals are identified, therapeutic strategies based on either different, more aggressive drugs or combinations of drugs can be used, either alone or in combination with shorter intervals for therapeutic monitoring. Pharmacogenetics is very likely to underlie future therapies for HIV-1 infection, and current patients with multi-resistance to the existing antiretroviral agents could also benefit from this approach. These developments also underscore the importance of continuing the investigation of new therapies targeted to the host in order to inhibit the HIV-1 entry into the host cells.

Stromal cell-derived factor 1 (SDF1) genetic polymorphism in a sample of healthy individuals, seronegative individuals exposed to human immunodeficiency virus type 1 (HIV-1) and patients infected with HIV-1 from the Brazilian population.

The interaction of viral and host factors is believed to determine not only the risk for initial human immunodeficiency virus type 1 (HIV-1) acquisition but also the course of the infection. Genetic polymorphisms in the chemokine receptors and their ligands were related to the susceptibility and resistance to HIV-1 infection. A polymorphism in the conserved 3' untranslated region of the stromal cell-derived factor-1 (SDF1) gene, which encodes a ligand of the CXCR4 receptor, has been related either to delayed progression to AIDS or to rapid disease progression and death. Global, regional, and ethnic distributions of frequencies of SDF1 genotypes and of the SDF1-3'A allele vary significantly. Although the HIV-1 epidemic is increasing in Brazil, little information about the frequencies of host genetic mutations related to HIV/AIDS resistance in the Brazilian population has been reported. To address this question, this study was carried out in order to determine the frequencies of the SDF1 polymorphism and the SDF1-3'A allele on 1061 genomic DNA samples purified from peripheral blood cells of 136 healthy individuals (group 1), 147 HIV-1-exposed seronegative individuals (group 2), 161 HIV-1-infected asymptomatic individuals and with CD4(+) T-cells count 350 mm(-3) (group 3), and 617 HIV-1-infected individuals with AIDS and/or CD4(+) T-cells count < 350 mm(-3) (group 4). The frequencies of the SDF1-3'A homozygous mutation were 3.7%, 6.1%, 4.3%, and 5.3% among groups 1, 2, 3, and 4, respectively (P = 0.5120). The overall frequency of the SDF1-3'A allele was 0. 1984 and did not differ among the four groups (P = 0.2744). The results underscore the global distribution of the SDF1 polymorphism and the hypothesis that the SDF1-3'A allele, itself, may not be sufficient to prevent the risk of HIV-1 infection and may be not related to the progression of the disease in the Brazilian population.

Reactivity of antibodies from patients with acute and chronic paracoccidioidomycosis to a high molecular mass antigen from Paracoccidioides brasiliensis.

Yeast forms of Paracoccidioides brasiliensis produce polydispersed high molecular mass (h-MM) antigens. We investigated the antibodies to an h-MM antigen from P. brasiliensis by immunoblotting and ELISA in sera from paracoccidioidomycosis (PCM) patients. IgG from the sera of chronic PCM patients was able to recognize the h-MM antigen at a higher frequency in the cell-free antigen (CFA) (8/13) than in the somatic antigen (SA) (2/13), as assessed by immunoblotting. The CFA was fractionated by Sephadex G-200 chromatography, and fraction 17 (F17) with the h-MM antigen of approximately 366 kDa was used in ELISA to analyze specific levels of IgG and IgE. Patients with the chronic form showed significantly higher levels of IgG (P<0.05) but not IgE (P>0.05) to F17 by ELISA, compared to patients with the acute form or to healthy donors. In conclusion, CFA is better than SA as a source of the P. brasiliensis h-MM antigen. This study reveals a new characteristic to differentiate between the acute and chronic forms of PCM, by demonstrating a higher level of seric IgG to h-MM antigen in chronic compared to acute PCM patients.

The association of the HLA in patients with schizophrenia, schizoaffective disorder, and in their biological relatives.

To determine the association of the HLA in 50 patients with schizophrenia, schizoaffective disorder, 48 healthy controls, 41 biological relatives without psychiatric disease, and 48 biological relatives with mood disorder, the HLA genotype at the class I and class II were determined. The subjects were interviewed by structured diagnostic criteria categorized according to DSM-IV, axis I, (SCID-IV). Significant positive association was found with HLA-B.15 in patients, family with humor disorder and without mental disorder (p=0.003) and negative association of the HLA-B.35 in relatives without psychiatric disease (p=0.03). The HLA-B.15 frequency was significantly increased in a subgroup of patients with age at onset in the early 20s, lower educational achievement, occupational disability, chronically ill, more paranoid type. These findings suggest the existence of some involvement of an immunogenetic mechanism in a subgroup of schizophrenic, schizoaffective patients, and biological relatives.

Model of intracellular calcium cycling in ventricular myocytes.

We present a mathematical model of calcium cycling that takes into account the spatially localized nature of release events that correspond to experimentally observed calcium sparks. This model naturally incorporates graded release by making the rate at which calcium sparks are recruited proportional to the whole cell L-type calcium current, with the total release of calcium from the sarcoplasmic reticulum (SR) being just the sum of local releases. The dynamics of calcium cycling is studied by pacing the model with a clamped action potential waveform. Experimentally observed calcium alternans are obtained at high pacing rates. The results show that the underlying mechanism for this phenomenon is a steep nonlinear dependence of the calcium released from the SR on the diastolic SR calcium concentration (SR load) and/or the diastolic calcium level in the cytosol, where the dependence on diastolic calcium is due to calcium-induced inactivation of the L-type calcium current. In addition, the results reveal that the calcium dynamics can become chaotic even though the voltage pacing is periodic. We reduce the equations of the model to a two-dimensional discrete map that relates the SR and cytosolic concentrations at one beat and the previous beat. From this map, we obtain a condition for the onset of calcium alternans in terms of the slopes of the release-versus-SR load and release-versus-diastolic-calcium curves. From an analysis of this map, we also obtain an understanding of the origin of chaotic dynamics.

Mechanisms for discordant alternans.

INTRODUCTION: Discordant alternans has the potential to produce larger alternans of the ECG T wave than concordant alternans, but its mechanism is unknown. METHODS AND RESULTS: We demonstrate by one- and two-dimensional simulation of action potential propagation models that discordant alternans can form spontaneously in spatially homogeneous tissue through one of two mechanisms, due to the interaction of conduction velocity and action potential duration restitution at high pacing frequencies or through the dispersion of diastolic interval produced by ectopic foci. In discordant alternans due to the first mechanism, the boundaries marking regions of alternans with opposite phase arise far from the stimulus site, move toward the stimulus site, and stabilize. Dynamic splitting of action potential duration restitution curves due to electrotonic coupling plays a crucial role in this stability. Larger tissues and faster pacing rates are conducive to multiple boundaries, and inhomogeneities of tissue properties facilitate or inhibit formation of boundaries. CONCLUSION: Spatial inhomogeneities of electrical restitution properties are not required to produce discordant alternans.

Effect of the calcium phosphate-mediated RNA uptake on the transfer of cellular immunity of a synthetic peptide of HIV-1 to human lymphocytes by exogenous RNA.

It is known that exogenous RNA molecules can be taken up by eukaryotic cells and can exert a variety of biological effects both in vitro and in vivo. The modulation of human lymphocytes by exogenous RNAs has medical implications. The exogenous RNA used in this study was obtained from lymphoid organs of animals immunized with the synthetic peptide p12 of HIV-1 and was referred to as p12-RNA. Human lymphocytes were transfected with the p12-RNA and the transfer of immunoreactivity of p12 was assessed by the lymphocyte proliferation and the leukocyte adherence inhibition assays. Our results indicate that the transfer of cellular immune response to the p12 occurred in 9 donors (60%) who were named responsive individuals whereas 6 donors (40%) were non-responsives. We also found that the calcium phosphate-mediated RNA uptake method is effective in converting non-responsive into responsive donors. The calcium phosphate-mediated RNA uptake may also be used to increase the efficiency of RNA transfection in other models with medical implications and to contribute to a better understanding of the molecular events involved in the uptake of RNA. Our findings give support for the use of exogenous RNAs obtained from lymphoid organs of immunized animals with synthetic peptides of HIV-1 in the immune reconstitution of individuals infected with HIV-1.

Immunotherapy of metastases with lymphocytes treated with exogenous RNA in mice bearing B16 melanoma.

Subline B16-F10, a variant cell line of B16 melanoma, is highly metastatic to the lung when injected intravenously into C57BL/6 mice. This experimental metastasis model was used to test the anti-tumor effect of exogenous RNA extracted from the lymphoid organs of immunized animals with B16-F10 cells. This RNA preparation is referred to as B16-RNA. Adoptive immunotherapy with lymphocytes treated with B16-RNA was effective in reducing significantly the number of pulmonary metastatic nodules. Lymphocytes incubated with medium alone or with RNA from non-immunized animals (N-RNA) were used as controls. The ability of B16-RNA in modulating antimetastatic activity of normal lymphocytes is abolished by hydrolysis with KOH. This finding indicates that the integrity of the polynucleotide chain is essential for the activity of B16-RNA. The anti-tumor effect of lymphocytes treated with B16-RNA was enhanced by incubation with a low dose of interleukin-2 (IL-2). A possible role of the double-stranded RNA dependent protein kinase in this phenomenon is discussed.

Memory and complex dynamics in cardiac Purkinje fibers.

The contribution of cumulative changes in action potential duration (memory) to complex cellular electrophysiological behavior was investigated in canine cardiac Purkinje fibers. Complex behavior induced during constant pacing was caused by reciprocal interactions between the time to full repolarization (TFR), where TFR = response duration + latency, and the diastolic interval (DI). The relationship between TFR and the preceding DI during complex behavior differed from that obtained using a standard restitution protocol. In particular, higher-order periodicities and chaos were produced in fibers in which the restitution curve lacked the prerequisites for such behavior. To investigate whether shifts in the restitution curve might be expected during rapid pacing, the relationship between TFR of a test response (TFR(n + 1)) and the immediately preceding response (TFR(n)) was determined. For any fixed DI(n), reduction of TFR(n) from 240 to 130 ms was accompanied by a corresponding reduction of TFR(n + 1), whereas as TFR(n) was reduced further to 120 ms, TFR(n + 1) increased. Because of the dependence of TFR(n + 1) on TFR(n) (memory) and on the preceding DI(n) (restitution), the slope of the low-dimensional relationship between TFR(n + 1) and DI(n) at a constant pacing cycle length depended on the slopes of the restitution and memory functions. These results suggest that rapid accumulation and dissipation of memory may contribute importantly to complex electrical behavior in cardiac tissue.

Anti-tumor effect of splenocytes treated with RNA from animals immunized with bovine myelin basic protein.

Chemically and immunologically, myelin basic protein (MBP) is very similar with the basic protein extracted from animal and human tumors. The results of this study demonstrated that splenocytes from C57BL/6 mice bearing B16 melanoma cells are sensitized to MBP, suggesting that this protein may share common antigenic determinants with antigens from B16 melanoma cells. The RNA preparations isolated from lymphoid tissues of normal or immunized guinea pigs with bovine MBP are referred to as N-RNA or MBP-RNA, respectively. It was also found that MBP-RNA is active in transferring MBP reactivity to normal splenocytes whereas N-RNA had no effect. To investigate whether this transfer to MBP immunoreactivity could result in a protective immunity, C57BL/6 mice transplanted with B16 melanoma received normal splenocytes treated with N-RNA or MBP-RNA. Two weeks after injection of B16-F10 cells, the mice were sacrificed and the tumor of each animal was removed and weighed. A significant inhibition of B16 melanoma growth was only achieved in C57BL/6 mice treated by splenocytes incubated with MBP-RNA which acts as an anti-tumor RNA. In this context, MBP could be considered as a tumor antigen.