Terapia de defeito crítico em crânio de ratos pela associação de xenoenxerto bovino e células derivadas de periósteo autógeno

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Structural, functional, and bioinformatics studies reveal a new snake venom homologue phospholipase A(2) class

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Functional and Ultrastructural Analysis of Annexin A1 and Its Receptor in Extravasating Neutrophils during Acute Inflammation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An enzyme-linked immunosorbent assay (ELISA) for detection of antibodies against Toxocara vitulorum in water buffaloes

Toxocara vitulorum, a parasite of the small intestine of cattle and water buffaloes, is mainly acquired by calves via the colostrum/milk from infected cows. To understand the development of immune responses in calves, antibody levels to a soluble extract antigen (Ex) from T. vitulorum infective larvae were measured by an indirect ELISA with sera of 15 buffalo calves, which were sampled every 15 days for the first 180 days after birth and 9 buffalo cows during the perinatal period. From all serum samples examined during the first 180 days, antibody level was lowest and highest in calves at 1 day of age before and after suckling colostrum, respectively, suggesting that the origin of antibodies was the colostrum. Immediately after birth, antibody levels in suckled calves remained at high levels until day 15, began to decrease to lower levels between 15 and 30 days and remained relatively stable until 120 days. By comparing the immune responses of these animals with their parasitological status it was considered possible to determine if passively acquired or actively produced antibodies provided protection against the infection. High numbers of T. vitulorum eggs in the feces between 30 and 60 days indicated that passively acquired antibodies did not provide protection against the infection, at least during these first days, and the maximum fecal egg counts during 30-45 days were coincident with decreased antibody levels. Between 60 and 120 days, when serum antibodies were detected at reduced, but stable levels, adult nematodes were expelled from the intestines and no more T. vitulorum eggs were found, suggesting development of acquired resistance. However, the potential and functional protective role of the antibodies against T. vitulorum infection and the process of self-cure requires further investigation. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Cloning, overexpression, and purification of functional human purine nucleoside phosphorylase

Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolysis of the N-ribosidic bonds of purine nucleosides and deoxynucleosides. A genetic deficiency due to mutations in the gene encoding for human PNP causes T-cell deficiency as the major physiological defect. Inappropriate activation of T-cells has been implicated in several clinically relevant human conditions such as transplant tissue rejection, psoriasis, rheumatoid arthritis, lupus, and T-cell lymphomas. Human PNP is therefore a target for inhibitor development aiming at T-cell immune response modulation. In addition, bacterial PNP has been used as reactant in a fast and sensitive spectrophotometric method that allows both quantitation of inorganic phosphate (Pi) and continuous assay of reactions that generate P i such as those catalyzed by ATPases and GTPases. Human PNP may therefore be an important biotechnological tool for P i detection. However, low expression of human PNP in bacterial hosts, protein purification protocols involving many steps, and low protein yields represent technical obstacles to be overcome if human PNP is to be used in either high-throughput drug screening or as a reagent in an affordable P i detection method. Here, we describe PCR amplification of human PNP from a liver cDNA library, cloning, expression in Escherichia coli host, purification, and activity measurement of homogeneous enzyme. Human PNP represented approximately 42% of total soluble cell proteins with no induction being necessary to express the target protein. Enzyme activity measurements demonstrated a 707-fold increase in specific activity of cloned human PNP as compared to control. Purification of cloned human PNP was achieved by a two-step purification protocol, yielding 48 mg homogeneous enzyme from 1 L cell culture, with a specific activity value of 80 U mg -1. © 2002 Elsevier Science (USA). All rights reserved.

Functional activity of neutrophils and systemic inflammatory response of Down's syndrome patients with periodontal disease

Periodontal disease (PD) is characterized as an inflammatory process that compromises the support and protection of the periodontium. Patients with Down's syndrome (DS) are prone to develop PD. Neutrophils (NE) are the first line of defense against infection and their absence sets the stage for disease. Aim: To compare the activity and function of NE in the peripheral blood from DS patients with and without PD, assisted at the Center for Dental Assistance to Patients with Special Needs affiliated with the School of Dentistry of Araçatuba, Brazil. Methods: Purified NE were collected from peripheral blood of 22 DS patients. NE were used to detect the 5-lypoxigenase (5-LO) expression by RT-PCR. Plasma from peripheral blood was collected to measure tumor necrosis factor-a (TNF-α) and interleukin-8 (IL-8) by ELISA and nitrite (NO 3) using a Griess assay. Results: Data analysis demonstrated that DS patients with PD present high levels of TNF-a and IL-8 when compared with DS patients without PD. However, there was no statistically significant difference in the levels of NO 3 production between the groups. The levels of the inflammatory mediator 5-LO expression increased in DS patients with PD. Conclusions: According with these results, it was concluded that TNF-α and IL-8 are produced by DS patients with PD. Furthermore, DS patients with PD presented high levels of 5-LO expression, suggesting the presence of leukotriene B 4 (LTB 4) in PD, thus demonstrating that the changes in NE function due to the elevation of inflammatory mediators contribute to PD.