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Objetivo: Diferenciar el angiomiolipoma atípico del carcinoma de células renales del mismo tamaño mediante hallazgos tomográficos. Materiales y métodos: Se realizó un estudio retrospectivo con 68 pacientes (17 con angio-miolipomas atípicos y 51 con carcinoma de células renales) nefrectomizados por diagnóstico presuntivo preoperatorio, mediante tomografía computada trifásica (fases sin contraste, corticomedular y excretora temprana), de carcinoma de células renales menor de 45mm. Dos radiólogos que desconocían el diagnóstico definitivo evaluaron retrospectivamente las características generales del tumor, su atenuación en fase sin contraste y las características de su realce. Se realizó un análisis estadístico con software R, aplicándose el modelo logit para diferenciar el angiomiolipoma atípico del carcinoma de células renales a partir de los hallazgos tomográficos de masa renal, incluidos en el modelo final el contorno, la atenuación en fase sin contraste y el patrón de realce con el tiempo. Resultados: Los hallazgos de angiomiolipoma atípico que resultaron significativos fueron atenuación tumoral en fase sin contraste hiperdensa y patrón de realce con tiempo prolongado con chance de ocurrencia de 10,49 (p=0,0381) y 36,71 (p=0,0009), respectivamente. En los pacientes, según el valor de cada hallazgo incluido en el modelo, se calculó probabilidad, sensibilidad (0,2941) y especificidad (0,9804). La curva característica operativa del receptor (ROC) determinó un punto de corte óptimo (0,9694) para discriminar el angiomiolipoma atípico, por lo que se confirmó su presencia. Conclusión: La tomografía computada helicoidal trifásica es útil para diferenciar el angiomiolipoma atípico del carcinoma de células renales, siendo la atenuación hiperdensa sin contraste del tumor y su patrón de realce prolongado los hallazgos tomográficos más valiosos.

Objective: To compare various computed tomographic features of atypical angiomyolipoma with those of size-matched renal cell carcinoma. Materials and methods: Sixty-eight patients (17 with atypical angiomyolipomas and 51 with carcinoma renal cells) who had undergone nephrectomy by presumptive diagnosis of carcinoma renal cell<45mm on diameter by preoperative triphasic computed tomography (CT) (with unenhanced, corticomedullary, and early excretory phase scanning) were evaluated in a retrospective study. Two reviewers who were unaware of the diagnosis retrospectively recorded tumor attenuation on unenhanced scans, enhancement characteristics and general characteristics of the tumor. Statistical analysis was performed with R software, applying logit model to differentiate atypical angiomyolipoma from renal cell carcinoma from CT findings of renal mass, included in the final model the tumor margin, its attenuation on unenhanced scans and the enhancement pattern over time. Results: For atypical angiomyolipomas the most valuable CT findings were hyperdense attenuation tumour in unenhaced phase scan and prolonged enhancement pattern, with chance of occurrence of 10.49 (p=0.0381) and 36.71 (p=0.0009), respectively. In the patients, as each finding value in the model, probability, sensitivity (0.2941) and specificity (0.9804) was calculated ROC curve was constructed that determined optimal cutoff (0.9694) to discriminate atypical angiomyolipoma, confirming their presence. Conclusion: Triphasic helical CT may be useful in differentiating atypical angiomyolipoma from renal cell carcinoma, with hyperdense tumor attenuation on unenhanced scans and prolonged enhancement pattern being the most valuable CT findings.

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To investigate the importance of serine proteases in Leishmania amazonensis promastigotes, we analyzed the effects of classical serine protease inhibitors and a Kunitz-type inhibitor, obtained from sea anemone Stichodactyla helianthus (ShPI-I), on the viability and morphology of parasites in culture. Classical inhibitors were selected on the basis of their ability to inhibit L. amazonensis serine proteases, previously described. The N-tosyl-L: -phenylalanine chloromethyl ketone (TPCK) and benzamidine (Bza) inhibitors, which are potential Leishmania proteases inhibitors, in all experimental conditions reduced the parasite viability, with regard to time dependence. On the other hand, N-tosyl-lysine chloromethyl ketone (TLCK) did not significantly affect the parasite viability, as it was poor Leishmania enzymes inhibitor. Ultrastructural analysis demonstrated that both Bza and TPCK induced changes in the flagellar pocket region with membrane alteration, including bleb formation. However, TPCK effects were more pronounced than those of Bza in Leishmania flagellar pocket in plasma membrane, and intracellular vesicular bodies was visualized. ShPI-I proved to be a powerful inhibitor of L. amazonensis serine proteases and the parasite viability. The ultrastructural alterations caused by ShPI-I were more dramatic than those induced by the classical inhibitors. Vesiculation of the flagellar pocket membrane, the appearance of a cytoplasmic vesicle that resembles an autophagic vacuole, and alterations of promastigotes shape resulted.

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A serine protease was purified 942-fold from culture supernatant of L. amazonensis promastigotes using (NH4)2SO4 precipitation followed by affinity chromatography on aprotinin-agarose and continuous elution electrophoresis by Prep Cell, yielding a total recovery of 61%. The molecular mass of the active enzyme estimated by SDS-PAGE under conditions of reduction was 56 kDa and 115 kDa under conditions of non-reduction, suggesting that the protease is a dimeric protein. Additionally, it was found to be a non-glycosylated enzyme, with a pI of 5.0. The optimal pH and temperature of the enzyme were 7.5 and 28 degrees C respectively, using alpha-N-rho-tosyl-L-arginine-methyl ester (L-TAME) as substrate. Assays of thermal stability indicated that 61% of the enzyme activity was preserved after 1 h of pre-treatment at 42 degrees C. Haemoglobin, bovine serum albumin (BSA), ovalbumin, fibrinogen, collagen, gelatin and peptide substrates containing arginine in an ester bond and amide substrates containing hydrophobic residues at the P1 site were hydrolysed by this extracellular protease. The insulin beta-chain was also hydrolysed by the enzyme and many peptidic bonds were susceptible to the protease action, and 4 of them (L11-V12, E3-A14, L15-Y16 and Y16-L17) were identified. Inhibition studies suggested that the enzyme belongs to the serine protease class inhibited by calcium and manganese and activated by zinc. These findings show that this enzyme of L. amazonensis is a novel serine protease, which differs from all known flagellate proteases characterized.

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Extracellular proteolytic activity was detected in a Leishmania ( L.) amazonensis culture supernatant and a 56-kDa protein was purified using (NH4)2SO4 precipitation followed by affinity chromatography on aprotinin-agarose. A rabbit serum obtained against the 56-kDa extracellular serine protease was used in order to analyze its location in L. ( L.) amazonensis parasites. Immunocytochemistry studies revealed that the enzyme is mainly found in the flagellar pocket and cytoplasmic vesicles of promastigote forms, whereas in amastigotes, it is located in electron-dense structures resembling megasomes. These results indicate that the 56-kDa serine protease is released into the extracellular environment through the flagellar pocket; and its intracellular location suggests either a correlated enzymatic activity or intracellular trafficking.

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A case-control study was undertaken to evaluate the possible relationship between cholecystectomy and right colon cancer. Two hundred patients with adenocarcinoma of the cecum or ascending colon (diagnosed between 1984 and 1989) were compared with 200 matched neighborhood controls. Cholecystectomy history was obtained through interviews using structured questionnaires and subsequently validated from hospital records. A statistically significant association (odds ratio = 2.14) was found between right colon cancer and a history of prior cholecystectomy. The altered bile metabolism which occurs after removal of the gallbladder may have a carcinogenic effect on the right colon. Dietary habits of the colon cancer patients in our study were consistent with prior reports in the literature, showing that this group has a lower intake of vegetables and cereal fiber than the control population.

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