Phagocytosis of apoptotic cells: a matter of balance.

Efficient clearance of apoptotic cells is required to control homeostasis in normal and pathological circumstances, and inappropriate clearance of cell corpses may lead to autoimmune diseases and inflammation. The multiplicity of phagocytotic mechanisms points to the relevance of removing apoptotic cells. A variety of surface molecules present in either the apoptotic bodies or phagocytes help in attachment and initiation of engulfment. Nonetheless, uncontrolled phagocytosis of apoptotic cells and other particles may lead to tissue injury; therefore, negative signals are important in balancing phagocytotic activity. This review aims at a systematic examination of positive and negative signals that modulate the uptake of apoptotic bodies and the signaling mechanisms involved in the clearance of apoptotic cells.

[Frequency of stenosis of renal the artery in 676 renal transplantations]. / Freqüência de estenose de artéria renal em 676 transplantes renais.

UNLABELLED: Kidney transplantation is the permanent and safe treatment for patients with chronic renal failure, although surgical treatment is susceptible both to urological and many vascular complications, and post-transplantation, renal artery stenosis being the most important. OBJECTIVE: To verify the incidence of renal artery stenosis of 676 patients submitted to renal transplants, from living and cadaver donors, in the period of February of 1985 to December of 1994, when compared the end-to-end and end-to-side anastomosis with the external iliac-artery of the recipient. METHODS: The data shown were obtained from charts of 676 patients submitted to renal transplants performed by the same surgery staff at the Hospital São Paulo--Universidade Federal de São Paulo--Escola Paulista de Medicina, between 1985 and 1994. RESULTS: Eleven cases (1.63%) of post-transplantation renal artery stenosis were found. CONCLUSION: 1) Frequency of post-transplantation renal artery stenosis was low and observed only in recipients of cadavers donors. 2) Frequency of post-transplantation renal artery stenosis with end-to-end artery anastomosis did not significantly differ from end-to-side anastomosis. 3) Age, sex and ethnic groups of patients did not interfere in the frequency of renal artery stenosis.