Showing papers by "Federal University of São Paulo published in 1991"

Complement-mediated lysis of Trypanosoma cruzi trypomastigotes by human anti-alpha-galactosyl antibodies.

Abstract: Antibodies that lyse trypomastigotes in a complement-mediated reaction are believed to be the main participants in the protection against virulent Trypanosoma cruzi Antibodies with a specificity for alpha-galactosyl-containing determinants--generally called antiGal--were studied to determine their role in the lysis of trypomastigote forms The titers of antiGal markedly increase in Chagas's disease In the present study we demonstrate binding of this antibody to T cruzi and the complement-mediated lysis of trypomastigotes by antiGal Lysis of metacyclic trypomastigotes by whole Chagasic (Ch) serum or isolated antiGal fractions was equally inhibited by alpha- but not by beta-galactosides Most of the lytic power of the Ch antiGal as well as of the whole Ch serum was removed by absorption on Synsorb-linked Gal alpha 1, 3Gal beta 1, 4GlcNAc followed by rabbit erythrocyte absorption The Ch antiGal had a lower affinity for melibiose bound to agarose than for the trisaccharide linked to Synsorb, and was several times more effective in the immunolysis of trypomastigotes than the corresponding antiGal from normal human serum Lytic antibodies were partly absorbed by Serratia marcescens but not by Escherichia coli O111 A human volunteer immunized with an S marcescens vaccine elicited a specific antiGal response that was lytic to trypomastigotes (70% lysis) We suggest that in vivo high-affinity antiGal antibody clones, as occur in Ch patients, may significantly contribute to the destruction of the parasite, whereas low-affinity antiGal clones are much less effective in the protection against T cruzi infection

Prognostic factors in laryngeal cancer patients submitted to surgical treatment.

Abstract: The authors studied some demographic, clinical, pathologic, and therapeutic variables in relation to the disease-free interval (DFI) and to the overall survival of laryngeal cancer patients. The patient population consisted of 278 consecutive cases of primary laryngeal cancer who had been admitted to four head and neck surgery services in Sao Paulo and Curitiba (Brazil) between 1973 and 1986. All patients had surgical treatment. Although several variables exhibited individual associations with survival, only a few were deemed to have independent prognostic value using multivariate regression techniques based on Cox's proportional hazards model. The primary tumor stage (T index) represented the variable with the highest predictive strength with respect to survival. Hazard ratios for the risk of disease recurrence were 2.3 (T2-3 vs. T1) and 4.3 (T4 vs. T1). Hazard ratios for the risk of death were 1.6 (T2-3 vs. T1) and 3.3 (T4 vs. T1). The following additional factors were also independently associated with the DFI: age, site of primary tumor (transglottic, glottic, or supraglottic), extracapsular spread of lymph node metastasis, surgical margins, type of paratracheal node dissection, and prior tracheostomy. Except for extracapsular spread, the same factors related to the DFI were also significantly related to the overall survival. Race, sex, N-stage, vascular embolization, and histological grade were other independent predictors of the risk of death.

Intraocular lens implantation in anterior megalophthalmus. Case report.

Abstract: We report three cases of extracapsular cataract extraction with intraocular lens implantation in two patients with anterior megalophthalmus. This is the first report, to our knowledge, of intraocular lens implantation in this rare condition.

Decrease in sulphated glycosaminoglycans in aortic dissection—possible role in the pathogenesis

Abstract: Study objective — The aim was to investigate alterations in sulphated glycosaminoglycans in aortic dissection. Design — Aortic fragments were taken from 10 patients within the first 3 d after onset of symptoms of aortic dissection and from nine age matched patients with no aortic disease. Sulphated glycosaminoglycans were analysed and quantified by agarose gel electrophoresis and densitometry after degradation with specific enzymes. Measurements and main results — The amount of chondroitin sulphate was similar (7.14 ν 7.60 mg·g−1 of dry tissue, n = 10, p>0.5) in patients with dissection and in the control group. Total sulphated glycosaminoglycan content was decreased (11.51 ν 14.26 mg·g−1 of dry tissue, n = 10, p<0.001). This difference was due to heparan sulphate (1.79 ν 2.48 mg·g−1 of dry tissue, n = 10, p<0.05) and mainly to dermatan sulphate (2.58 ν 4.18 mg·g−1 of dry tissue, n = 10, p<0.001). The ratio of 6-/4-sulphated disaccharides after chondroitinase ABC digestion was increased in the affected group. No correlation between these biochemical results and a histological evaluation of mucoid content was found. On the other hand, a significant increase in chondroitin sulphate could be observed related to aging. Conclusions — The diminution in sulphated glycosaminoglycans and its possible relationship with fat, collagen, and other extracellular matrix molecules could lead to a weakness in the aortic wall related to the dissection.

Reinnervation of the transplanted vas deferens : differential recovery of various biochemical and pharmacological parameters

Abstract: Biochemical and pharmacologcial parameters were used to follow the innervation characteristics of the rat was deferens transplanted (T) to the caecum. After about 5 months, a regeneration of autonomic nerves was clearly shown: first, by a complete recovery of neuronal uptake, indicated by: a) potentiation by cocaine of epinephrine (EPI) dose-response curves (T=1.47±0.25, controls (C)=1.50±0.14 log units); b) reversion to normal levels of pD2 values for norepinephrine (NE) and EPI (T=6.6.±0.1; 7.0±0.1, and C=6.4±0.1; 6.9±0.1, respectively); second, a partial restoration of nerve terminals, and corresponding pools of NE, which was seen through histofluorescence and was indicated by a percent increase of: a) NE content, 47% (T=3.8±0.8, C=8.5±0.7 =μg/g); b) dopamine-β-hydroxylase (DBH) activity, 37% (T=136±80, C=364±15 nmol(hr.g); c) release of NE by 57 mM-potassium, 23% (T=33.0±12.0, C=147±14 ng/g. 5 min). Yet, two peculiarities of denervated organs remained practically unchanged even after 5-month transplantation: NE supersensitivity, measured by the relative responsiveness (p) ratio (T=0.96±0.02, C=0.69±0.03), and tyramine-induced contraction, that was recovered by only 14% (T=10.0±2.4, C=72.0±3.5 mm). This differential recovery of the forementioned parameters is discussed in the light of receptor mechanisms and functional changes following reinnervation.

Increased expression of laminin receptors during myeloid differentiation

Abstract: Variation of laminin receptor levels (LNR) during myeloid-cell differentiation and in acute leukemia were investigated by 125I-laminin-binding determination during HL60 cell differentiation and in cells of patients with different types of leukemia, characterized according to the FAB classification. LNR levels in HL60 cells increased during differentiation, being significantly higher in cells exposed to phorbol myristate acetate (PMA) and ethanol (55,391 +/- 27,845 and 29,314 +/- 6,435 sites/cell respectively) as compared with HL60 controls (8,549 +/- 4,000 sites/cell). The control cells do not adhere to laminin-coated surfaces, but differentiation with PMA results in their rapid adherence on this substratum. Short treatment with PMA does not increase the number of adherent cells or the receptor expression. Granulocytes also presented equally high LNR concentration (29,739 +/- 13,516 sites/cell). The lymphoid cells (lymphocyte, acute lymphoid leukemia and chronic lymphocytic leukemia) shared low LNR numbers (less than 6,500 sites/cell). Myeloid cells displayed a wide range of LN receptors with higher levels being associated with the more differentiated FAB subgroups. 125I-laminin binding to lymphoid or myeloid leukemic cells was mainly inhibited by P1 fragments, whereas granulocytes and differentiated HL60 cells displayed a dual binding pattern for laminin fragments P1 and E8. These results were confirmed by assays using 125I-labelled P1 and E8 fragments. We conclude that magnitude of LNR levels and variation in expression of P1 and E8 receptors appear to be linked to lineage and maturation status in hematopoietic cells.