Prevalence and risk factors for anti-Toxoplasma gondii antibodies in goats of the Serido Oriental microregion, Rio Grande do Norte state, Northeast region of Brazil

The prevalence and risk factors for anti-Toxoplasma gondii antibodies were investigated in goats of the Serido Oriental microregion, Rio Grande do Norte state, Northeast region of Brazil. Three hundred and sixty-six blood samples from goats collected by jugular venopuncture were used. For the serologic diagnosis of Toxoplasma gondii infection, the indirect fluorescent-anti body test (IFAT) with cut-off value 1:64 was carried out. The prevalence of anti-T. gondii antibodies was 30.6% [95% CI = 25.9-35.6%] with titers ranging from 1:64 to 1: 16,384. The multivariate logistic regression analysis showed that the risk factors associated to anti-T. gondii antibodies were presence of cats in the herd, extensive/semi-intensive management systems and lack of mineral supplementation. (c) 2008 Elsevier B.V. All rights reserved.

Squamous Cell Carcinoma of the Tongue and Floor of the Mouth: Analysis of Survival Rate and Independent Prognostic Factors in the Amazon Region

Oral squamous cell carcinoma (OSCC) accounts for more than 95% of all malignant neoplasms in the oral cavity. Although several studies have shown the epidemiology of this cancer in Brazil, there do not seem to be any studies that describe the prognostic factors related to OSCC in the Amazon region. Therefore, the aim of this study was to determine the survival rate and prognostic significance of different factors in patients from this region affected by OSCC. Data from 85 patients with histologically confirmed squamous cell carcinoma of the tongue and floor of the mouth identified from the Ofir Loyola Hospital archives were collected and analyzed using univariate (log-rank test) and multivariate (Cox proportional hazard model) tests. The overall 5-year survival rate was found to be 27%. Univariate analysis showed that the 5-year survival rate was significantly higher for younger (<= 45 y) female patients, patients with T1-2 tumors and clinically clear neck nodes (N0), patients with early stage cancers (AJCC stage I-II), and patients treated with surgical procedures. However, multivariate analysis showed that the 5-year survival rate was significantly higher only in the younger patients and those who underwent surgical treatment. The age of the patient at the moment of diagnosis and treatment with surgical procedures were the only independent prognostic factors that affected the 5-year survival rate of the patients in this region.

Assessment of the Availability of Bone Volume for Grafting in the Donor Retromolar Region Using Computed Tomography: A Pilot Study

Purpose: The purpose of this study was to evaluate the area and volume of bone available for grafting in a donor retromolar region using computed tomography (CT). Materials and Methods: Ten patients previously scanned by multislice CT were selected for evaluation. Images from partially and completely dentate patients at least 18 years of age were included in the study; those from patients with impacted or erupted third molars or intrabony lesions in the study area were not included. Computer software with appropriate tools was used to handle the images. Two calibrated observers made measurements separately. Safety margins in relation to the lingual cortex, the base of mandible, and the alveolar canal were established in each cross-section of the CTs. Measurements were done by using cross-sectional views, and the results were calculated after three-dimensional reconstruction, providing area and volume data. Results: The mean area of bone available for grafting was 8.12 cm(2) ( range, 0.00 to 13.60 cm(2)) and 8.32 cm(2) ( range, 0.00 to 14.30 cm(2)) for observers 1 and 2, respectively. Mean available bone volume for grafting was 0.79 cm(3) ( range, 0.00 to 1.50 cm(3)) for observer 1 and 0.85 cm(3) ( range, 0.00 to 1.60 cm(3)) for observer 2. Interobserver analysis showed substantial agreement. Conclusion: The retromolar region showed a wide variety of anatomic differences among patients. Three-dimensional multislice CT allows reproducible measurements of the area and volume of the retromolar region. Int J Oral Maxillofac Implants 2010; 25: 374-378

Patients with oral squamous cell carcinoma are characterized by increased frequency of suppressive regulatory T cells in the blood and tumor microenvironment

Oral squamous cell carcinoma (OSCC) is a cancerous lesion with high incidence worldwide. The immunoregulatory events leading to OSCC persistence remain to be elucidated. Our hypothesis is that regulatory T cells (Tregs) are important to obstruct antitumor immune responses in patients with OSCC. In the present study, we investigated the frequency, phenotype, and activity of Tregs from blood and lesions of patients with OSCC. Our data showed that > 80% of CD4(+)CD25(+) T cells isolated from PBMC and tumor sites express FoxP3. Also, these cells express surface Treg markers, such as GITR, CD45RO, CD69, LAP, CTLA-4, CCR4, and IL-10. Purified CD4(+)CD25(+) T cells exhibited stronger suppressive activity inhibiting allogeneic T-cell proliferation and IFN-gamma production when compared with CD4(+)CD25(+) T cells isolated from healthy individuals. Interestingly, approximately 25% of CD4(+)CD25(-) T cells of PBMC from patients also expressed FoxP3 and, although these cells weakly suppress allogeneic T cells proliferative response, they inhibited IFN-gamma and induced IL-10 and TGF-beta secretion in these co-cultures. Thus, our data show that Treg cells are present in OSCC lesions and PBMC, and these cells appear to suppress immune responses both systemically and in the tumor microenvironment.

Characterization of CD4(+)CD25(+) natural regulatory T cells in the inflammatory infiltrate of human chronic periodontitis

Periodontitis is an infectious disease, where putative periodontopathogens trigger chronic inflammatory and immune responses against periodontal structures, in which an unbalanced host response is also determinant to the disease outcome. It is reasonable to assume that patient susceptibility to periodontal tissue destruction could be determined by the balance between the response against periodontopathogens and regulatory mechanisms of these events mediated by suppressive T cells. In the present study, we identified and characterized natural regulatory T cells ( Tregs) in the inflammatory infiltrate of human chronic periodontitis ( CP) with emphasis on phenotypic analyses that were carried out to address the participation of Tregs in CP. Results showed that patients with CP presented increased frequency of T lymphocytes and CD4(+)CD25(+) T cells in the inflammatory infiltrate of gingival tissues. These cells exhibited the phenotypic markers of Tregs such as forkhead box p3 ( Foxp3), CTLA- 4, glucocorticoidinducible TNFR, CD103, and CD45RO and seemed to be attracted to the inflammation site by the chemokines CCL17 and CCL22, as their expression and its receptor CCR4 were increased in CP patients. Moreover, besides the increased detection of Foxp3 mRNA, diseased tissues presented high expression of the regulatory cytokines IL-10 and TGF-beta. In addition, the inflammatory infiltrate in CP biopsies was composed of CD25(+)Foxp3(+) and CD25(+)TGF-beta(+) cells, thus corroborating the hypothesis of the involvement of Tregs in the pathogenesis of CP. Finally, these results indicate that Tregs are found in the chronic lesions and must be involved in the modulation of local immune response in CP patients.

CCR5-dependent regulatory T cell migration mediates fungal survival and severe immunosuppression

Paracoccidioidomycosis, a debilitating pulmonary mycosis, is caused by the dimorphic fungus Paracoccidioides brasiliensis. The infection results in the formation of granulomas containing viable yeast cells that are the fungal sources for disease reactivation. Because CD4(+)CD25(+) regulatory T cells (Tregs) are in the lesions of patients with paracoccidioidomycosis, the migration of Treg cells is dependent on the axis chemokine-chemokine receptors, and CCR5 ligands are produced in P. brasiliensis-induced lesions, we investigated the role of CCR5 in the control of the infection. The results showed that CCR5(-/-) mice are more efficient in controlling fungal growth and dissemination and exhibited smaller granulomas than wild-type (WT) mice. In the absence of CCR5, the percentage of CD4(+)CD25(+) T cells expressing Foxp3, glucocorticoid-induced TNFR (GITR), CD103, CD45(low), and CTLA-4 in the granulomas was significantly decreased. Interestingly, P. brasiliensis infection resulted in an absence of T cell proliferation in response to Con A in WT but not CCR5(-/-) mice that was abrogated by anti-CTLA-4 mAb and anti-GITR mAb. Moreover, the adoptive transfer of CD4(+)CD25(+) but not CD4(+)CD25(-) T cells from infected WT to infected CCR5(-/-) mice resulted in a significant increase in fungal load. Overall, CCR5 is a key receptor for the migration of Treg cells to the site of P. brasiliensis infections leading to down-modulation of effector immune response and the long-term presence of the fungus in the granulomas. Thus, a tight control of Treg cell migration to the granulomatous lesions could be an important mechanism for avoiding exacerbation and reactivation of the disease.

Human twinning is not linked to the region of chromosome 4 syntenic with the sheep twinning gene FecB

The tendency to dizygotic (DZ) twinning is inherited in both humans and sheep, and a fecundity gene in sheep (FecB) maps to sheep chromosome 6, syntenic with human 4q21-25. Our aim was to see whether a gene predisposing to human DZ twinning mapped to this region. DNA was collected from 169 pairs and 17 sets of 3 sisters (trios) from Australia and New Zealand who had each had spontaneous DZ twins, mostly before the age of 35, and from a replication sample of 111 families (92 affected sister pairs) from The Netherlands. Exclusion mapping was carried out after typing 26 markers on chromosome 4, of which 8 spanned the region Likely to contain the human homologue of the sheep FecB gene. We used nonparametric affected sib pair methods for linkage analysis [ASPEX 2.2, Hinds and Risch, 1999]. Complete exclusion of linkage (lod < -2) of a gene conferring a relative risk for sibs as low as 1.5 ((s) > 1.5) was obtained for all but the p terminus region on chromosome 4. Exclusion in the syntenic region was stronger, down to lambda (s) = 1.3. We concluded that if there is a gene influencing DZ twinning on chromosome 4, its effect must be minor. (C) 2001 Wiley-Liss, Inc.

Identification of the regulatory subunit of Arabidopsis thaliana acetohydroxyacid synthase and reconstitution with its catalytic subunit

Acetohydroxyacid synthase (EC 4.1.3.18; AHAS) catalyzes the initial step in the formation of the branched-chain amino acids. The enzyme from most bacteria is composed of a catalytic subunit, and a smaller regulatory subunit that is required for full activity and for sensitivity to feedback regulation by valine. A similar arrangement was demonstrated recently for yeast AHAS, and a putative regulatory subunit of tobacco AHAS has also been reported. In this latter case, the enzyme reconstituted from its purified subunits remained insensitive to feedback inhibition, unlike the enzyme extracted from native plant sources. Here we have cloned, expressed in Escherichia coil, and purified the AHAS regulatory subunit of Ambidopsis thaliana. Combining the protein with the purified A. thaliana catalytic subunit results in an activity stimulation that is sensitive to inhibition by valine, leucine, and isoleucine. Moreover, there is a strong synergy between the effects of leucine and valine, which closely mimics the properties of the native enzyme. The regulatory subunit contains a sequence repeat of approximately 180 residues, and we suggest that one repeat binds leucine while the second binds valine or isoleucine. This proposal is supported by reconstitution studies of the individual repeats, which were also cloned, expressed, and purified. The structure and properties of the regulatory subunit are reminiscent of the regulatory domain of threonine deaminase (EC 4.2.1.16), and it is suggested that the two proteins are evolutionarily related.

Japanese encephalitis on Badu Island, Australia: the first isolation of Japanese encephalitis virus from Culex gelidus in the Australasian region and the role of mosquito host-feeding patterns in virus transmission cycles

During investigation of an outbreak of Japanese encephalitis (JE) in the Torres Strait, Australia, in 2000, mosquitoes were collected in Badu Island community and at a newly established communal piggery about 3 km from the community. A total of 94285 mosquitoes, comprising 91240 (96.8%) unengorged females, 1630 (1.7%) blood-engorged females and 1415 (1.5%) males, were processed for virus isolation. One isolate of JE virus was obtained from Culex gelidus, with a minimum infection rate of 12.4:1000. This is the first isolate of JE virus from Cx. gelidus in the Australasian region. No isolates were obtained from Cx. annulirostris, the primary implicated Australian JE vector. Analysis of mosquito host-feeding patterns, using gel diffusion, demonstrated that Cx. annulirostris and 5 other species fed predominately on mammals, Analysis of blood-fed mosquitoes collected within the community demonstrated that the proportion of Cx. annulirostris feeding on pigs in 2000 (2.3%) was significantly lower than that for the 1995-97 period (31.3%). The removal of the pigs from Badu Island community has limited the contact between potential amplifying hosts and mosquitoes, thus potentially reducing the risk of transmission of JE virus to the human population.

The appearance of a second genotype of Japanese encephalitis virus in the Australasian region

In mid-January 2000, the reappearance of Japanese encephalitis (JE) virus activity in the Australasian region was first demonstrated by the isolation of JE virus from 3 sentinel pigs on Badu Island in the Torres Strait. Further evidence of JE virus activity was revealed through the isolation of JE virus from Cidex gelidus mosquitoes collected on Badu Island and the detection of specific JE virus neutralizing antibodies in 3 pigs from Saint Pauls community on Moa Island. Nucleotide sequencing and phylogenetic analyses of the premembrane and envelope genes were performed which showed that both the pig and mosquito JE virus isolates (TSOO and TS4152, respectively) clustered in genotype I, along with northern Thai, Cambodian, and Korean isolates. All previous Australasian JE virus isolates belong to genotype II, along with Malaysian and Indonesian isolates. Therefore, for the first time, the appearance and transmission of a second genotype of JE virus in the Australasian region has been demonstrated.

A molecular comparison of T lymphocyte populations infiltrating the liver and circulating in the blood of patients with chronic hepatitis B: Evidence for antigen-driven selection of a public complementarity-determining region 3 (CDR3) motif

Despite a large number of T cells infiltrating the liver of patients with chronic hepatitis B, little is known about their complexity or specificity. To characterize the composition of these T cells involved with the pathogenesis of chronic hepatitis B (CHB), we have studied the clonality of V beta T cell receptor (TCR)-bearing populations in liver tissue by size spectratyping the complementarity-determining region (CDR3) lengths of TCR transcripts. We have also compared the CDR3 profiles of the lymphocytes infiltrating the liver with those circulating in the blood to see whether identical clonotypes may be detected that would indicate a virus-induced expansion in both compartments. Our studies show that in most of the patients examined, the T cell composition of liver infiltrating lymphocytes is highly restricted, with evidence of clonotypic expansions in 4 to 9 TCR V beta subfamilies. In contrast, the blood compartment contains an average of 1 to 3 expansions. This pattern is seen irrespective of the patient's viral load or degree of liver pathology. Although the TCR repertoire profiles between the 2 compartments are generally distinct, there is evidence of some T cell subsets being equally distributed between the blood and the liver. Finally, we provide evidence for a putative public binding motif within the CDR3 region with the sequence G-X-S, which may be involved with hepatitis B virus recognition.