Publications by authors named "Waldir Pereira"

β-Glucosidases have been extensively investigated to integrate the enzyme complex for cellulose fiber saccharification and for improving the aroma of wine. To produce these enzymes, greater attention has been given to filamentous fungi and bacteria, and few investigations have targeted the potential applications of enzymes secreted by yeasts. Addressing this issue, in this study, β-glucosidases were produced by the and yeasts, via solid state fermentation with wheat bran as a substrate.

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Proteases are produced by the most diverse microorganisms and have a wide spectrum of applications. However, the use of wild microorganisms, mainly fungi, for enzyme production has some drawbacks. They are subject to physiological instability due to metabolic adaptations, causing complications and impairments in the production process.

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Aim: Maintenance therapy is an important phase of the childhood ALL treatment, requiring 2-year long therapy adherence of the patients and families. Weekly methotrexate with daily 6-mercaptopurine (6MP) constitutes the backbone of maintenance therapy. Reduction in the maintenance therapy could overweight problems related with poverty of children with ALL living in limited-income countries (LIC).

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Background: Large cooperative group studies have shown the efficacy of risk-adapted treatment for Ewing sarcoma. However, validation and local adaptation by National cooperative groups is needed. A multicenter protocol to determine the efficacy and safety of a risk-adapted intensive regimen was developed by the Brazilian cooperative group.

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The infections caused by Dipodascus capitatus are rare, and the treatment is difficult. We reported a case of a patient with acute myeloid leukemia. The fungus was first isolated from hemocultures, and the phenotypic identification was based on mycological methods.

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PURPOSE To describe event-free survival (EFS) and toxicities in children with low-risk acute lymphoblastic leukemia (ALL) assigned to receive either continuous 6-mercaptopurine (6-MP) and weekly methotrexate (MTX) or intermittent 6-MP with intermediate-dose MTX, as maintenance treatment. PATIENTS AND METHODS Between October 1, 2000, and December 31, 2007, 635 patients with low-risk ALL were enrolled onto Brazilian Childhood Cooperative Group for ALL Treatment (GBTLI) ALL-99 protocol. Eligible children (n = 544) were randomly allocated to receive either continuous 6-MP/MTX (group 1, n = 272) or intermittent 6-MP (100 mg/m(2)/d for 10 days, with 11 days resting) and MTX (200 mg/m(2) every 3 weeks; group 2, n = 272).

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Extramedullary involvement occurs infrequently in acute promyelocytic leukemia and is said to be more common after treatment with all-trans retinoic acid. We describe a 9-year-old girl who had an isolated external auditory canal and middle ear relapse after treatment with all-trans retinoic acid and chemotherapy. A patient with cytogenetically and molecularly confirmed acute promyelocytic leukemia developed isolated extramedullary relapse in the auditory canal and middle ear 4 years and 9 months after initial diagnosis, while in hematologic and molecular remission, successfully treated with arsenic trioxide alone.

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Rio Grande do Sul (RS), in South Brazil, with about 10 million inhabitants, is known for its agricultural activities and consequent increased human exposure to toxic agents. Patients with de novo acute myeloid leukemia (AML) were included based on information retrieved from all referral hospitals in RS between 1996 and 2000. A total of 532 patients were registered.

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The use of all trans-retinoic acid (ATRA) is the basis of treatment of acute promyelocytic leukemia (APL) and represents the paradigm of differentiation therapy. In general, ATRA is well-tolerated but may be associated with a potentially lethal side-effect, referred to as retinoic acid or differentiation syndrome (DS). The cellular and molecular mechanisms of DS are poorly understood and involve changes in the adhesive qualities and cytokine secretion of leukemic cells during ATRA-induced differentiation.

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The presence of the t(12;21)(p13;q22) distinguishes a subset of children with acute lymphoblastic leukemia (ALL) that present a favorable prognosis. This is a cryptic translocation difficult to detect through conventional cytogenetics. In this study, bone marrow samples from 30 children with ALL from southern Brazil were evaluated by fluorescence in situ hybridization (FISH) for the t(12;21), using locus specific probes to detect the TEL/AML1 rearrangement.

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