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Biomedical subjects

A P Ferreira

Publications and source records attributed to A P Ferreira.

At least 19 recordsLinked to original sources
PubMed2005

Usefulness of HBME-1, cytokeratin 19 and galectin-3 immunostaining in the diagnosis of thyroid malignancy.

AIMS: To investigate the usefulness of immunohistochemical expression and immunolocalization of a panel of thyroid malignancy markers including HBME-1, cytokeratin (CK) 19 and galectin-3. METHODS AND RESULTS: We evaluated 170 thyroid lesions including 148 neoplastic lesions [84 papillary carcinomas (PC), 38 follicular carcinomas (FC), 18 follicular adenomas, one hyalinizing trabecular tumour, five medullary carcinomas, two anaplastic carcinomas] and 22 non-neoplastic lesions (12 adenomatous nodules and 10 Hashimoto's thyroiditis). HBME-1, galectin-3 and CK 19 were expressed in 94%, 72.6%, 72.6% of PCs and in 63%, 21%, 21% of FCs. The three markers were mostly negative in all normal tissues. Although the most helpful marker in terms of sensitivity and specificity for the follicular variant of PC and for FC diagnosis was HBME-1, when we consider the differentiation between cases of follicular variant of papillary carcinoma (FVPC) and FC or adenoma, in terms of percentage of positive cells, galectin-3 and CK 19 were more relevant. CONCLUSIONS: HBME-1 is the most sensitive marker for thyroid malignancy but the three markers may be useful in specific cases. This panel of markers is useful to differentiate the follicular patterned lesions, with special reference to the FVPC.

Biomarkers, Tumor↗
PubMed2003

Immunomodulatory activity of Mollugo verticillata L.

This article describes the evaluation of immunomodulatory activity of Mollugo verticillata L. (Molluginaceae), a weed plant common in warm and/or wet regions of the American continent. Nitric oxide (NO) release was evaluated in mice peritoneal cell cultures treated in vivo using the ethanolic extract of M. verticillata with and without BCG. The plant extract showed immunostimulatory activity when peritoneal cells were stimulated in vitro with BCG antigen only. However, mice peritoneal cells treated with M. verticillata plus BCG showed a drastic reduction in NO production when they received the additional stimulus in vitro with BCG. Ethanolic extracts of M. verticillata could directly increase NO release by peritoneal cells, but suppress the immune response of these cells when treated with BCG antigen and Mycobacterium tuberculosis whole antigen (TB). Preliminary phytochemical tests allowed the detection of quercetin and triterpenoid glycosides in the ethanolic extract of M. verticillata, and those compounds are probably responsible for the effect of this plant material on the immune system.

Adjuvants, Immunologic↗
PubMed2001

Development of an evanescent-field fibre optic sensor for Escherichia coli O157:H7.

An intensity-modulated fibre optic sensor was developed for Escherichia coli O157:H7. The interaction between the whole natural bacteria and the guided lightwave was carried out by means of evanescent-field coupling. A correlation between optical response and the current number of bacteria was achieved. The device sensitivity had been calibrated for initial number of bacteria (N(0)) from 10-800. The sensor sensitivity was 0.016 (+/-0.001) dB/h/N(0). The sensing mechanism starts together with the log phase leading the present sensor response to be five to ten times faster than conventional bacteriological techniques.

Biosensing Techniques↗
PubMed1999

Effect of the injection of an extract of Ascaris suum on macrophage activation during the early phase of Mycobacterium bovis BCG infection in C57Bl/6 mice.

Injection of an Ascaris suum extract (Asc) affects both the humoral and cellular immune responses to unrelated antigens when it is co-administered with these antigens. In the present study we evaluated the effect of Asc on macrophage activation in the early phase of Mycobacterium bovis BCG (Pasteur strain TMCC 1173) infection in C57Bl/6 mice. C57Bl/6 mice were injected intraperitoneally (ip) with 0.1 mg BCG (BCG group) or BCG plus 1 mg Asc (BCG + Asc group). The peritoneal exudates were obtained at 2, 7 and 14 days after infection. The numbers of IFN-gamma-secreting cells were assessed by the ELISPOT assay. Nitric oxide (NO) production was measured by the Griess method and by the evaluation of NADPH diaphorase activity in the peritoneal exudates. The administration of Asc extract increased NADPH diaphorase activity (2 days: control = 0, BCG = 7%, BCG + Asc = 13%, and Asc = 4%; 7 days: control = 4, BCG = 13%, BCG + Asc = 21%, and Asc = 4.5%) and TNF-alpha levels (mean +/- SD; 2 days: control = 0, BCG = 169 +/- 13, BCG + Asc = 202 +/- 37, and Asc = 0; 7 days: control = 0, BCG = 545 +/- 15.5, BCG + Asc = 2206 +/- 160.6, and Asc = 126 +/- 26; 14 days: control = 10 +/- 1.45, BCG = 9 +/- 1.15, BCG + Asc = 126 +/- 18, and Asc = 880 +/- 47.67 pg/ml) in the early phase of BCG infection. Low levels of NO production were detected at 2 and 7 days after BCG infection, increasing at 14 days (mean +/- SD; 2 days: control = 0, BCG = 3.7 +/- 1.59, BCG + Asc = 0.82 +/- 0.005, Asc = 0.48 +/- 0.33; 7 days: control = 0, BCG = 2.78 +/- 1.54, BCG + Asc = 3.07 +/- 1.05, Asc = 0; 14 days: control = 0, BCG = 9.05 +/- 0.53, BCG + Asc = 9.61 +/- 0.81, Asc = 10.5 +/- 0.2 (2 x 10(6)) cells/ml). Furthermore, we also observed that Asc co-injection induced a decrease of BCG-colony-forming units (CFU) in the spleens of BCG-infected mice during the first week of infection (mean +/- SD; 2 days: BCG = 1.13 +/- 0.07 and BCG + Asc = 0.798 +/- 0.305; 7 days: BCG = 1.375 +/- 0. 194 and BCG + Asc = 0.548 +/- 0.0226; 14 days: BCG = 0.473 +/- 0.184 and BCG + Asc = 0.675 +/- 0.065 (x 10(2)) CFU). The present data suggest that Asc induces the enhancement of the immune response in the early phase of BCG infection.

Animals↗
PubMed1998

ELISA for the detection of venom antigens in experimental and clinical envenoming by Loxosceles intermedia spiders.

Enzyme linked immunosorbent assays (ELISA) were developed to detect antigens from Loxosceles intermedia spider venom. Hyperimmune horse anti-Loxosceles intermedia IgGs were prepared by immunoaffinity chromatography and used to set up a sandwich-type ELISA. The specificity of the assay was demonstrated by its capacity to correctly discriminate the circulating antigens in mice that were experimentally inoculated with L. intermedia venom from those inoculated with L. gaucho, L. laeta, and Phoneutria nigriventer spider venoms, Tityus serrulatus scorpion venom and Bothrops jararaca, Crotalus durissus terrificus, Lachesis muta muta and Micrurus frontalis snake venoms. Measurable absorbance signals were obtained with 0.8 ng of venom per assay. The ELISA also detected antigens in the sera of patients envenomed by L. intermedia. Therefore, after standardization for clinical use this ELISA may be a valuable tool for clinicians and epidemiologists.

Adult↗
PubMed1998

Immunomodulation induced by Ascaris suum extract in mice: effect of anti-interleukin-4 and anti-interleukin-10 antibodies.

Simultaneous immunization of mice with an Ascaris suum extract (Asc) and ovalbumin (OA) markedly affects the immune response to OA. The role of interleukin (IL)-4 and IL-10 induced by Asc immunization on the modulation of antigen-specific and mitogen-induced responses was investigated following single or combined cytokine-specific monoclonal antibody (MoAb) treatment of mice before immunization with OA + Asc. Immediate hypersensitivity reactions to aggregated OA and OA-specific immunoglobulin (Ig)G2a antibody production were completely restored only when both IL-4 and IL-10 were neutralized. These findings were associated with enhanced interferon (IFN)-gamma secretion by OA-stimulated lymph node (LN) cells. In addition, the Asc-specific cytokine response in anti-IL-4 plus anti-IL-10 MoAb treated mice was shifted towards a Th1 phenotype, with an increase in IFN-gamma and IL-2 levels and a decrease in IL-4, but not in IL-10, levels. Consequently, Asc-specific IgG2a antibody production increased, whereas IgE titres diminished in these animals. These results indicate that IL-4 and IL-10 act together in the Asc-induced mechanism of antigen-specific pansuppression. In contrast, modulation of Concanavalin A (Con A)-induced cytokine responses in Asc-immunized mice appears to be essentially mediated by an IL-4-dependent mechanism, since the neutralization of just IL-4 (and not of IL-10), either in vivo or in vitro, changed the cytokine profile from a Th2 towards a Th1 type. However, OA and Asc-specific cell responses were not modified by either anti-IL-4 or by anti-IL-4 + anti-IL-10 MoAbs in vitro treatments, suggesting that the induction of a Th2 response to Asc components concomitant to OA immunization has a strong suppressive effect on the priming stage of OA-specific Th1 type response.

Adjuvants, Immunologic↗
PubMed1998

Congenital absence of parotid glands and lacrimal puncta.

Bilateral parotid aplasia and lacrimal puncta are a rare disorder. A case is presented in which the clinical diagnosis was confirmed by ultrasonography. The importance to dentists in early recognition of bilateral parotid aplasia and lacrimal puncta is emphasized.

Child↗
PubMed1997

An enzyme-linked immunosorbent assay (ELISA) that discriminates between the venoms of Brazilian Bothrops species and Crotalus durissus.

Enzyme-linked immunosorbent assays (ELISAs) were developed to detect specific antigens from Bothrops sp. and Crotalus durissus snake venoms in Brazil. Cross-reactive immunoglobulins from hyperimmune horse anti-Bothrops and anti-Crotalus sera were removed by immunoaffinity chromatography. Specific IgGs for Bothrops sp. and C. durissus venom antigens were prepared and used to set up a sandwich-type ELISA. The specificity of the assay was demonstrated by its capacity to identify correctly the circulating antigens in mice experimentally inoculated with both venoms. Measurable absorbance signals were obtained with 5 ng of venom per assay. The ELISA was also used to identify circulating antigens in the sera of humans bitten by Bothrops sp. and C. durissus. These ELISAs could be valuable for clinicians and epidemiologists if they prove to have both the high sensitivity and specificity required for such tests.

Animals↗
PubMed1997

Neutralizing capacity of antibodies elicited by a non-toxic protein purified from the venom of the scorpion Tityus serrulatus.

Polyclonal rabbit antibodies raised against a non-toxic protein (TsNTxP) purified from the toxic fraction of the crude venom of Tityus serrulatus can neutralize the effects of the venom. The antigenic specificities of anti-TsNTxP were compared by an indirect enzyme-linked immunosorbent assay using TsNTxP, TstFG50 (toxic fraction of venom that represents most of the toxicity of the crude venom), and crude venoms from T. serrulatus, T. bahiensis, T. cambridgei, T. stigmurus, Androctonus australis Hector and Centruroides sculpturatus to coat microtitration plates. The anti-TsNTxP antibodies had a comparable high cross-reactivity with the toxic fraction and crude venom of T. serrulatus, moderate binding capacity for T. bahiensis, T. cambridgei, T. stigmurus and were unable to recognize the venoms of A. australis Hector and C. sculpturatus. Quantities of venom equivalent to 20 LD50 were effectively neutralized by 1 ml of the anti-TsNTxP serum. This result shows that this protein may be of interest in the production of antivenoms for clinical use.

Amino Acid Sequence↗
PubMed1996

Pharmacokinetics of Tityus serrulatus scorpion venom determined by enzyme-linked immunosorbent assay in the rat.

Experiments were performed in two groups of anaesthetized rats to study the genesis of pulmonary oedema and to determine the pharmacokinetic parameters following a subcutaneous (s.c.) injection of Tityus serrulatus scorpion venom. In group I, the rats were anaesthetized with pentobarbital (4 mg/100 g, i.p.); the s.c. injection of scorpion venom at the dose of 50 micrograms/100 g did not induce arterial hypertension, but unilateral pulmonary oedema was observed in three of six rats. The injection of a higher dose of venom (200 micrograms/100 g, N = 6) induced arterial hypertension and bilateral (N = 3) or unilateral (N = 1) pulmonary oedema. These data indicate that it is possible to evoke unilateral pulmonary oedema without previous arterial hypertension induced by the venom. For the study of pharmacokinetic parameters a second group of six rats was anaesthetized with urethane (140 mg/ 100 g, i.p.) and the venom injected at a dose of 200 micrograms/100 g, s.c. The plasma concentrations of venom were determined by enzyme-linked immunosorbent assay, at times 0, 5, 30, 60, 180, 360, and 720 min after venom injection. A biphasic curve was obtained with an ascending phase followed by a descending phase. The maximum plasma scorpion venom concentration was reached at 60 min. The pharmacokinetic parameters showed a fast absorption rate (Ka = 0.058 min-1), a fast and high distribution of venom to tissues (t1/2 alpha = 31.50 min and Vdarea = 6800.47 ml.kg-1, respectively), a great affinity of the venom for the tissues (KCT = 0.056 min-1 and KTC = 0.002 min-1) and a slow elimination half-life (t1/2 beta = 173.25 min).

Analysis of Variance↗
PubMed1996

Body distribution of Tityus serrulatus scorpion venom in mice and effects of scorpion antivenom.

In the present study we report the distribution of Tityus serrulatus scorpion venom in serum and various tissues of CFI mice and the efficacy of antivenom in reducing venom concentration. The animals were injected s.c. with 10 micrograms of scorpion venom, divided into groups of four animals and killed at different times from 15 min to 24 hr. Blood samples and samples of different tissues (heart, lung, liver, kidney, spleen, brain and injection site) were collected. Maximum venom levels occurred at 15 min in the kidney and liver and at 30 min in serum, lung, heart and spleen. After 2 hr the venom decreased rapidly in serum and in all other organs until venom levels were no longer detectable after 8 hr. No venom was detected in the central nervous system. In another experiment, 10 microliters of scorpion antivenom was injected i.v. together with the venom, and a rapid reduction of venom concentration was observed in the blood and tissues. In the third experiment, anti-scorpion venom was injected i.v. 1 hr after venom administration, and partial reduction of venom concentration was detected in tissues (lung and kidney). These studies contribute to the elaboration of more objective treatment that may result in a more economic, efficient and controlled use of scorpion antivenom in stings involving humans.

Animals↗
PubMed1995

Immunization with Ascaris suum extract impairs T cell functions in mice.

The effect of an Ascaris suum extract (Asc) on several T cell functions was studied in mice immunized with Asc and ovalbumin (OA) in complete Freund's adjuvant. Delayed-type hypersensitivity reactions following challenge with aggregated OA were markedly diminished in mice injected with OA plus a high dose of Asc compared to OA-immunized animals. Proliferation and IL-2, IFN-gamma, IL-4, and IL-10 production in OA-stimulated lymph node cells from the OA + Asc-immunized group were also inhibited. Titration of anti-OA antibodies also showed suppression of IgG1, IgG2a, and IgE isotypes in the animals injected simultaneously with the extract. The degree of suppression induced by Asc on OA-specific cell-mediated responses was dose dependent. The profile of cytokines synthesized in response to Asc also changed depending on the injected dose. IL-4 and IL-10 were mainly produced in response to high doses, whereas IL-2 and IFN-gamma were greatly enhanced at a low dose of Asc. These findings indicate that the A. suum extract may impair crucial T cell functions for cell-mediated as well as humoral immune responses to other antigens through the induction of a predominantly Th2-like response.

Animals↗
PubMed1991

Suppression of antibody response to an unrelated antigen in experimental murine paracoccidioidomycosis: effect of cyclophosphamide and indomethacin.

A suppressive effect of experimental paracoccidioidomycosis on the IgE antibody response to an unrelated antigen (ovalbumin) has been previously observed in mice. This effect was restricted to a short period, reaching maximum levels when OA was administered on the third day of Pb-infection. In order to study possible mechanisms involved in the establishment of this suppression, resistant (A/SN) and susceptible (B10.A) mice were treated with either a low dose of cyclophosphamide (CY) or indomethacin (INDO), a potent inhibitor of prostaglandin synthesis. While treatment with the first drug in A/SN mice induced only a recovery of the IgE anti-OA antibody response, in B10.A mice this effect was extended to IgG1, IgG2a and total levels of anti-OA antibodies. On the other hand, treatment with INDO reverted the anti-OA antibody suppression regarding each antibody class tested and in both strains of mice. These results suggest the participation of prostaglandins and of a cyclophosphamide-sensitive mechanism in the induction of the suppressive phenomenon in the human system.

Animals↗
PubMed1991

PAF antagonists do not modify IgE antibody production in mice.

The effect of selective PAF antagonists on the in vivo production of IgE antibodies was investigated. The anti-ovalbumin IgE antibody content was estimated by passive cutaneous anaphylactic reaction (PCA) in the plasma of Balb/c mice 10 days after immunization with ovalbumin and alum. The PAF antagonists, BN 52021 (5 mg/kg, ip), BN 50730 (20 mg/kg, po), WEB 2086 (2 mg/kg, ip) and WEB 2170 (5 mg/kg, ip) were administered 1 h before immunization and twice a day for 8 days thereafter. The effect of the antagonists on the PAF-induced vasopermeability was also assayed. In the immunized mice the level of antiovalbumin IgE antibody, estimated by PCA titer, was 1/640. The treatment with the PAF antagonists did not change this level. At the concentrations employed, the antagonists BN 50730, WEB 2086 and WEB 2170 significantly reduced the PAF-induced vascular permeability. These results suggest that PAF does not seem to have a relevant effect on the production of IgE antibodies in vivo in the system used in the present study.

Animals↗
PubMed1978

Fractures and dislocations of the ankle joint.

The classification of fractures of the ankle joint is based on the mechanism of injury, which provides the clue to successful reduction. The physiological movements of the ankle and foot are defined, and the pathological movements associated with injury are described.

Ankle Injuries↗