Crystallization and preliminary crystallographic analysis of SMase I, a sphingomyelinase from Loxosceles laeta spider venom.

SMase I, a 32 kDa sphingomyelinase found in Loxosceles laeta venom, is responsible for the major pathological effects of spider envenomation. This toxin has been cloned and functionally expressed as a fusion protein containing a 6 x His tag at its N-terminus to yield a 33 kDa protein [Fernandes-Pedrosa et al. (2002), Biochem. Biophys. Res. Commun. 298, 638-645]. The recombinant protein possesses all the biological properties ascribed to the whole L. laeta venom, including dermonecrotic and complement-dependent haemolytic activities. Dynamic light-scattering experiments conducted at 291 K demonstrate that the sample possesses a monomodal distribution, with a hydrodynamic radius of 3.57 nm. L. laeta SMase I was crystallized by the hanging-drop vapour-diffusion technique using the sparse-matrix method. Single crystals were obtained using a buffer solution consisting of 0.08 M HEPES and 0.9 M trisodium citrate, which was titrated to pH 7.5 using 0.25 M sodium hydroxide. Complete three-dimensional diffraction data were collected to 1.8 angstroms at the Laboratório Nacional de Luz Síncrotron (LNLS, Campinas, Brazil). The crystals belong to the hexagonal system (space group P6(1) or P6(5)), with unit-cell parameters a = b = 140.6, c = 113.6 angstroms. A search for heavy-atom derivatives has been initiated and elucidation of the crystal structure is currently in progress.

[Spinal cord involvement in Burkitt-type lymphoma: report of a case]. / Comprometimento medular por linfoma tipo Burkitt: relato de um caso.

Case report of Burkitt's type lymphoma with involvement of the spinal cord in a three years-old child. An epidural tumoral mass (T11-L1) was removed surgically (Fig. 2), and clinical conditions improved for a short period of time (1 and 1/2 months) after which symptoms reappeared. At this occasion a computerized tomography showed a tumoral mass occupying the spinal canal with high density at the L2 level. The patient died 6 months after the beginning of the disease. General considerations are made on Burkitt's lymphoma.

[Fibromyxosarcoma in a child; report of a case]. / Fibromixosarcoma em criança; registro de um caso.

The case of a six-year old boy's with intracranial hypertension and cranial deformities is reported. Radiological examination showed signs of intracranial hypertension and a large osteolitic area in the left posterior parietal region. Cerebral cintilography showed many abnormal captation areas. Pneumoencephalography showed deformation of the ventricular system without dilatation. Angiographic study gave images of tumoral compression by meningitic processes. Craniotomy in the osteolytic area showed an infiltrating tumoration between dura and piamater, reaching frontal, temporal and bilateral parietal areas. Histopathological examination confirmed the diagnostic of fibromixosarcoma.

[Hemangioblastoma of supra-tentorial location]. / Hemangioblastoma de localização supra-tentorial

A case of hemangioblastoma with supra-tentorial localization is reported. General considerations are made.