Rac2 GTPase activation by angiotensin II is modulated by Ca2C/calcineurin and mitogen-activated protein kinases in human neutrophils

Angiotensin II (Ang II) highly stimulates superoxide anion production by neutrophils. The G-protein Rac2 modulates the activity of NADPH oxidase in response to various stimuli. Here, we describe that Ang II induced both Rac2 translocation from the cytosol to the plasma membrane and Rac2 GTP-binding activity. Furthermore, Clostridium difficile toxin A, an inhibitor of the Rho-GTPases family Rho, Rac and Cdc42, prevented Ang II-elicited O2-/ROS production, phosphorylation of the mitogen-activated protein kinases (MAPKs) p38, extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase 1/2, and Rac2 activation. Rac2 GTPase inhibition by C. difficile toxin A was accompanied by a robust reduction of the cytosolic Ca(2)(+) elevation induced by Ang II in human neutrophils. Furthermore, SB203580 and PD098059 act as inhibitors of p38MAPK and ERK1/2 respectively, wortmannin, an inhibitor of phosphatidylinositol-3-kinase, and cyclosporin A, a calcineurin inhibitor, hindered both translocation of Rac2 from the cytosol to the plasma membrane and enhancement of Rac2 GTP-binding elicited by Ang II. These results provide evidence that the activation of Rac2 by Ang II is exerted through multiple signalling pathways, involving Ca(2)(+)/calcineurin and protein kinases, the elucidation of which should be insightful in the design of new therapies aimed at reversing the inflammation of vessel walls found in a number of cardiovascular diseases.

Lipoprotein lipase activity and mass, apolipoprotein C-II mass and polymorphisms of apolipoproteins E and A5 in subjects with prior acute hypertriglyceridaemic pancreatitis

BACKGROUND Severe hypertriglyceridaemia due to chylomicronemia may trigger an acute pancreatitis. However, the basic underlying mechanism is usually not well understood. We decided to analyze some proteins involved in the catabolism of triglyceride-rich lipoproteins in patients with severe hypertriglyceridaemia. METHODS Twenty-four survivors of acute hypertriglyceridaemic pancreatitis (cases) and 31 patients with severe hypertriglyceridaemia (controls) were included. Clinical and anthropometrical data, chylomicronaemia, lipoprotein profile, postheparin lipoprotein lipase mass and activity, hepatic lipase activity, apolipoprotein C II and CIII mass, apo E and A5 polymorphisms were assessed. RESULTS Only five cases were found to have LPL mass and activity deficiency, all of them thin and having the first episode in childhood. No cases had apolipoprotein CII deficiency. No significant differences were found between the non-deficient LPL cases and the controls in terms of obesity, diabetes, alcohol consumption, drug therapy, gender distribution, evidence of fasting chylomicronaemia, lipid levels, LPL activity and mass, hepatic lipase activity, CII and CIII mass or apo E polymorphisms. However, the SNP S19W of apo A5 tended to be more prevalent in cases than controls (40% vs. 23%, NS). CONCLUSION Primary defects in LPL and C-II are rare in survivors of acute hypertriglyceridaemic pancreatitis; lipase activity measurements should be restricted to those having their first episode during childhood.

Use of palliative radiotherapy in brain and bone metastases (VARA II study).

INTRODUCTION Metastases are detected in 20% of patients with solid tumours at diagnosis and a further 30% after diagnosis. Radiation therapy (RT) has proven effective in bone (BM) and brain (BrM) metastases. The objective of this study was to analyze the variability of RT utilization rates in clinical practice and the accessibility to medical technology in our region. PATIENTS AND METHODS We reviewed the clinical records and RT treatment sheets of all patients undergoing RT for BM and/or BrM during 2007 in the 12 public hospitals in an autonomous region of Spain. Data were gathered on hospital type, patient type and RT treatment characteristics. Calculation of the rate of RT use was based on the cancer incidence and the number of RT treatments for BM, BrM and all cancer sites. RESULTS Out of the 9319 patients undergoing RT during 2007 for cancer at any site, 1242 (13.3%; inter-hospital range, 26.3%) received RT for BM (n = 744) or BrM (n = 498). These 1242 patients represented 79% of all RT treatments with palliative intent, and the most frequent primary tumours were in lung, breast, prostate or digestive system. No significant difference between BM and BrM groups were observed in: mean age (62 vs. 59 yrs, respectively); gender (approximately 64% male and 36% female in both); performance status (ECOG 0-1 in 70 vs. 71%); or mean distance from hospital (36 vs. 28.6 km) or time from consultation to RT treatment (13 vs. 14.3 days). RT regimens differed among hospitals and between patient groups: 10 × 300 cGy, 5 × 400 cGy and 1x800cGy were applied in 32, 27 and 25%, respectively, of BM patients, whereas 10 × 300cGy was used in 49% of BrM patients. CONCLUSIONS Palliative RT use in BM and BrM is high and close to the expected rate, unlike the global rate of RT application for all cancers in our setting. Differences in RT schedules among hospitals may reflect variability in clinical practice among the medical teams.