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Biomedical subjects

F E Pereira

Publications and source records attributed to F E Pereira.

At least 19 recordsLinked to original sources
PubMed2001

Short report: do intestinal nematodes increase the risk for multibacillary leprosy?

Intestinal helminths are known to subvert the host's immune response towards a Th2 response, which in turn may lead to both eosinophilia and high immunoglobulin E titers often associated with these parasites. Mycobacterium leprae infection may lead to different clinical and pathological forms. Multibacillary forms are associated with Th2 cytokines, whereas paucibacillary forms are associated with Th1 cytokines. We report a significantly higher frequency of intestinal helminthic infections in patients with the lepromatous form, a multibacillary form of leprosy (odds ratio, 2.99; 95% confidence interval, 1.82-4.95; P = 0.006) when compared with patients with paucibacillary leprosy or to a control group without leprosy. A direct correlation was also found between mycobacterial index and the frequency of intestinal helminths. Our results suggest that the presence of intestinal helminths may facilitate the establishment of M. leprae infection or the progression to more severe forms of leprosy.

Adolescent↗
PubMed2000

Intestinal nematodes, Toxocara infection, and pyogenic liver abscess in children: a possible association.

Eosinophilia and intestinal helminths are frequent in children with pyogenic liver abscess (PLA) diagnosed in Vitória (Brazil). For these reasons we hypothesized that nematode infection with larvae migrating through the tissues (Ascaris, Strongyloides, Ancylostoma, Necator and Toxocara) may be a predisposing factor for PLA in children. We compared the prevalence of intestinal helminth and Toxocara infection between children with PLA and a control group of children with no evidence of PLA at the Children's Hospital N.S. da Glória in Vitória. From October 1996 to February 1998, 13 children with PLA and 110 children with diseases other than PLA provided five stool samples (Hoffman, Baerman and Kato-Katz methods) and one blood sample for anti-Toxocara antibodies (ELISA IgG, with previous adsorption with Ascaris suum antigen). All PLA and comparison children belonged to a low socioeconomic class and lived in similar conditions. The frequency of intestinal nematodes and anti-Toxocara antibodies were significantly higher in PLA patients than in controls (intestinal helminths: 10/13 or 76.9 per cent in PLA cases and 31/110 or 28.1 per cent in controls; OR = 8.94; 95 per cent confidence interval (CI): 1.97 < OR < 50.06; anti-Toxocara antibodies: 9/13 or 69.2 per cent in PLA and 31/110 or 28.1 per cent in controls; OR = 6.59; 95 per cent CI: 1.65 < OR < 31.05). Moreover, the degree of eosinophilia was higher in PLA patients. Malnutrition was present in both groups. Hemoglobin was 9.5 g/dl in PLA patients and 9.7 g/dl in controls; p = 0.900. Serum levels of IgA and IgM were normal or above normal, with no difference between the two groups, but the levels of IgG and IgE were higher in PLA patients. Although there is some missing data in respect to some socioeconomic parameters in affected and comparison groups. these results support the hypothesis that helminth infection with larvae migrating through tissues may be a predisposing factor for PLA in children. Th2 cell activation and downregulation of Th1 cells, induced by helminths, thus reducing the microbicidal activity of phagocytes, as well as the granulomatous reaction around the larvae (mainly of Toxocara sp.) causing the trapping of bacteria in liver, may be possible explanations for the increased risk for PLA in children with intestinal nematodes and/or Toxocara infection.

Animals↗
PubMed1992

Histamine levels in tissues of Trypanosoma cruzi-infected mice.

Histamine levels of several organs from mice chronically infected with a myotropic strain of Trypanosoma cruzi were determined by bioassay. An increase in histamine content was observed in stomach, small intestine, colon, heart and skeletal muscle, when compared with noninfected weight and age-matched mice. These results suggest that mast cells, the main storage site of peripheral histamine, can play a role in the inflammatory and/or immunologic components of experimental trypanosomiasis.

Animals↗
PubMed1988

Chronotropic responses to acetylcholine in atria of mice chronically infected with Y and CL strains of Trypanosoma cruzi.

Cardiac parasympathetic denervation has been reported to occur in human and experimental T. cruzi infections. We have used acetylcholine to investigate the in vitro chronotropic sensitivity of atrial muscarinic receptors in mice chronically infected with either a reticulotropic (Y) or a myotropic (CL) strain of T. cruzi. The dose-response curves did not differ from that obtained for control mice, a result that may be due to reinnervation processes.

Acetylcholine↗
PubMed1987

Trypanosoma cruzi (CL strain) infection in mice changes the chronotropic effect of isoproterenol in vitro.

Cardiac autonomic denervation has been reported to occur in experimental T. cruzi infection. We used isoproterenol (IP) to investigate the in vitro chronotropic sensitivity of atrial beta-adrenoceptors from mice acutely (30 days) or chronically (180 days) infected with T. cruzi, CL strain (a myotropic strain). Displacement of the dose-response curve to IP to the right occurred in the acute phase group. In the chronic phase group the opposite effect occurred (hyperreactivity to IP) although to a lesser extent. These results suggest that infection of mice with this strain of T. cruzi induces quantitative or qualitative changes in atrial beta-adrenoceptors.

Animals↗
PubMed1981

The association of hepatitis B surface antigen (HBs Ag) with hepatocellular carcinoma in Espírito Santo State, Brazil.

1. The occurrence of hepatitis B surface antigen (HBs Ag) was investigated in 46 cases of hepatocellular carcinoma (HCC) diagnosed in Vitória, Espírito Santo State, Brazil. 2. Twenty cases were patients in which the HCC was diagnosed by biopsy, laparoscopy or on autopsy from 1977 to 1980. HBs Ag was measured in the serum by reverse passive hemagglutination (13 cases) and radioimmunoassay (7 cases). Twelve cases (60%) were HBs Ag positive. 3. The presence of HBs Ag was studied in 26 cases diagnosed on autopsy using paraffin-embedded liver sections stained with orcein. Eleven cases (42%) showed orcein granules in hepatocytes surrounding the tumor. In only one case were orcein-positive granules detected in the tumor cells. 4. The 50% incidence of HBs Ag among patients with HCC is higher than the occurrence of HBs Ag in the general population of the State of Espírito Santo, i.e. 3.5% among 1300 blood donors to the University Hospital. 5. These data provide additional evidence for the hypothesis that there is a relationship between the hepatitis B virus and the etiology of HCC.

Adolescent↗