Crab-eating fox (Cerdocyon thous), a South American canid, as a definitive host for Hammondia heydorni

Hammondia heydorni is a cyst forming coccidia closely related to other apicomplexans, such as Toxoplasma gondii, Neospora caninum and Hammondia hammondi with a two-host life cycle. Dogs and other canids as red foxes (Vulpes vulpes) and coyotes (Canis latrans) may serve as definitive hosts for H. heydorni. Sporulated oocysts are infective for cattle, sheep and goats, which may serve as intermediate hosts. Herein, we describe the ability of crab-eating fox (Cerdocyon thous), a wild carnivore that is commonly found from northern Argentina to northern South America, to serve as definitive host of H. heydorni. The whole masseter muscle and brain from two 2-year-old bovines were collected, minced and pooled together for the fox infection. The bovine pooled tissues were equally administered to four foxes, in two consecutive days. Two foxes shed subspherical unsporulated oocysts measuring 10-15 mu m, after 8 and 9 days post-infection, respectively. One of the foxes eliminated oocysts for 5 days, while the other fox shed oocysts for 9 days. A DNA sample of oocysts detected at each day of oocyst elimination was tested by two PCRs, one of them carried out employing primers directed to the common toxoplasmatiid 18S and 5.8S ribosomal RNA coding genes (PCR-ITS1) and the other based on heat-shock protein 70 kDa coding gene (PCR-HSP70). These samples were also submitted to a N. caninum specific nested-PCR protocol based on a N. caninum specific gene (Nc5-nPCR). All of them were positive by PCR-ITS1 and PCR-HSP70 but negative by Nc5-nPCR. The PCR-ITS1 and PCR-HSP70 nucleotide sequences amplified from the oocysts shed by the foxes revealed 100% identity with homologous sequences of H. heydorni. In conclusion, it is clear that H. heydorni also uses the crab-eating fox as a definitive host. The crab-eating fox is usually reported to live in close contact with livestock in several regions of Brazil. Therefore, it is reasonable to infer that such carnivores may play an important role in the sylvatic and domestic cycles of H. heydorni infection. (C) 2009 Elsevier B.V. All rights reserved.

The success of endosseous implants in human immunodeficiency virus-positive patients receiving antiretroviral therapy A pilot study

Background. In a pilot study, the authors aimed to determine the success rate of dental implants placed in patients who were positive for human immunodeficiency virus (HIV) and were receiving different regimens of highly active anti-retroviral therapy (HAART). They considered patients` levels of cluster of differentiation (CD) 4(+) cells and viral load, and they attempted to verify whether patients with baseline biochemical signs of bone mineral density loss could experience osseointegration impairment. Materials and Methods. One of the authors, a dentist, placed dental implants in the posterior mandibles of 40 volunteers, divided into three groups: one composed of HIV-positive patients receiving protease inhibitor (PI)-based HAART; a second composed of HIV-positive patients receiving nonnucleoside reverse transcriptase inhibitor based HAART (without PI); and a control group composed of HIV-negative participants. The authors assessed pen-implant health six and 12 months after implant loading. They analyzed the success of the implants in relation to CD4(+) cell counts, viral load and baseline pyridinoline and deoxypyridinoline values. Results. The authors followed 59 implants for 12 months after loading. Higher baseline levels of pyridinoline and deoxypyridinoline found in HIV-positive participants did not interfere with osseointegration after 12 months of follow-up. Average pen-implant bone loss after 12 months was 0.49 millimeters in group 1, 0.47 mm in group 2, and 0.55 mm in the control group. Conclusions. The placement of dental implants in HIV-positive patients is a reasonable treatment option, regardless of CD4(+) cell count, viral load levels and type of antiretroviral therapy. Longer, follow-up periods are necessary to ascertain the predictability of the long-term success of dental implants in these patients. Clinical Implications. Limited published scientific evidence is available to guide clinicians in regard to possible increased risks associated with dental implant placement in HIV-positive patients.

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.