Isolation of an aspartic proteinase precursor from the egg of a hard tick, Boophilus microplus.

An aspartic proteinase precursor, herein named BYC (Boophilus Yolk pro-Cathepsin) was isolated from eggs of the hard tick, Boophilus microplus. As judged by electrophoresis on sodium dodecyl sulfate polyacrylamide slab gel (SDS-PAGE), purified BYC presented 2 bands of 54 and 49 kDa, bearing the same NH2-terminal amino acid sequence. By Western blot analysis, BYC was also found in the haemolymph, indicating an extraovarian site of synthesis. Several organs were incubated in culture medium with [35S]methionine, and only the gut and fat body showed synthesis of BYC polypeptides. Protein sequencing of both the NH2-terminal and an internal sequence obtained after cyanogen bromide (CNBr) cleavage of BYC revealed homology with several aspartic proteinase precursors. Incubation at pH 3.5 resulted in autoproteolysis of BYC, which produced the mature form of the enzyme, that displayed pepstatin-sensitive hydrolytic activity against haemoglobin. Western blot analysis using anti-BYC monoclonal antibodies showed proteolytic processing of BYC during embryogenesis and suggested activation of the enzyme during development. A role of BYC in degradation of vitellin, the major yolk protein of tick eggs, is discussed.

Changing patterns of vitellin-related peptides during development of the cattle tick Boophilus microplus.

The major components of protein extracts from the cattle tick Boophilus microplus eggs and larvae of various ages were characterized by molecular sieving chromatography, ion exchange chromatography and SDS-PAGE. The fractions analysed showed a changing chromatographic pattern development. A serum raised against the components of a fraction showing characteristics of vitellin strongly reacted in Western blots with the major peptides of extracts from eggs, larvae, gut and ovary. Comparison of patterns obtained by electrophoresis in non-denaturing PAGE, stained with Coomassie blue or with benzidine/hydrogen peroxide, revealed that the major proteins of these extracts are haemoproteins, possibly in different aggregation states or heterogeneous in composition.

Ocorrência de Boophilus microplus livre de Babesia spp em regiäo indene (Santa Vitória do Palmar, RS, Brasil) / Occorrence of Boophilus microplus free from Babesia spp in undamaged region (Santa Vitória do Palmar, RS, Brazil)

A entrada de animais infestados por carrapatos nas regiöes livres, nos meses de veräo, provoca surtos de tristeza parasitária nos animais nativos, que normalmente se encontram sem proteçäo para esta enfermidade. Nos veröes de 1987 e 1988, ocorreram vários focos isolados de carrapatos em Santa Vitória do Palmar, regiäo indene do extremo sul do Brasil. O presente trabalho teve como objetivo colaborar no esclarecimento do assunto, chegando os autores à conclusäo de que o carrapato ali existente é o Boophilus microplus, naturalmente livre de Babesia spp

Total disconnection of the right ventricular free wall: surgical treatment of right ventricular tachycardia associated with right ventricular dysplasia.

Arrhythmogenic right ventricular dysplasia is a myopathy that affects the right ventricular free wall (RVFW) and gives rise to recurrent reentrant ventricular tachycardia (VT). Because the entire right ventricle is potentially arrhythmogenic, ablating a single site of VT may not eliminate the arrhythmia. We developed an operation to confine any arrhythmic activity arising from the right ventricle to that chamber: total disconnection of the RVFW from the left ventricle. We performed RVFW disconnection in two patients with refractory VT associated with arrhythmogenic right ventricular dysplasia. At least two sites or origin of morphologically distinct VT were identified in the RVFW in each patient. RVFW disconnection was carried out under normothermic cardiopulmonary bypass. An encircling incision was made along the attachment of the RVFW to the aortoventricular unit and the tricuspid annulus; the right coronary artery and its RVFW branches were left intact. Electrical activity of the two chambers became dissociated, and VT arising from the RVFW was confined to that chamber. Postoperatively, there was no clinical evidence of hemodynamic impairment (follow-up 4 months and 3 months). Left ventricular function was unchanged and right ventricular flow was maintained by atrial contraction and motion of the septum toward the RVFW during left ventricular systole. One patient had incessant right ventricular tachycardia confined to the RVFW for 3 weeks. We conclude that RVFW disconnection is feasible and applicable to patients with refractory VT originating in the diffusely diseased RVFW.

Varices colonicas. Presentacion de dos casos y revision de la literatura / Colonic varices. Report of 2 cases and review of the literature

Se presentan 2 pacientes con varices colonicas. Se hace una breve revision de la literatura, la cual incluye un total de otros 33 casos. La mayoria de los pacientes tienen hipertension portal. El motivo de consulta mas frecuente es el sangramiento rectal. La endoscopia es el metodo mas util para el diagnostico. El tratamiento que mejores resultados parece dar en los casos de hemorragia masiva es la anatomosis porto-cava

Tumor-induced hypoglycemia: a result of ectopic insulin production.

A 73-year-old woman with a pelvic tumor of nerve cell origin who presented with recurrent episodes of hypoglycemia was demonstrated to have inappropriately elevated plasma insulin and hypoglycemia. The tumor contained Insulin (RIA), proinsulin and secretory type of granules. Removal of the tumor promptly produced hyperglycemia. Also no islet cell tumor was found in the pancreas, suggesting the tumor as the site of ectopic insulin production.