Biomedical subjects

Philippe Patra

Publications and source records attributed to Philippe Patra.

5 recordsLinked to original sources

PubMed2006

Hyaluronan induces vascular smooth muscle cell migration through RHAMM-mediated PI3K-dependent Rac activation.

OBJECTIVE: Hyaluronan (HA) is an important constituent of the extracellular matrix and is known to regulate cellular events through binding to CD44 and the receptor for HA-mediated motility (RHAMM). Here we investigated the role of these receptors and the signaling pathways involved in HA-mediated effects in arterial smooth muscle cells (ASMC). METHODS: Effects of high-molecular weight HA (1 to 5 mg/ml) were analyzed in cultured ASMC from rat aorta. RESULTS: HA promoted actin stress fiber and lamellipodia formation and dose-dependently induced ASMC migration without effect on proliferation. Pull-down assay of Rho protein activity indicated that HA activated RhoA and Rac. HA-induced ASMC migration was not affected by the RhoA inhibitor Tat-C3 (10 microg/ml), the Rho kinase inhibitor Y-27632 (10 microM) and blocking anti-CD44 antibody ,but was reduced by the non-selective Rho protein inhibitor simvastatin (10 microM), the Rac inhibitor LT-toxin (1 mug/ml), small interfering RNA (siRNA) targeting Rac and the phosphatidyl inositol 3-kinase (PI3K) inhibitor LY294002 (25 microM), which also blocked HA-induced Rac activation. CD44 knockdown by siRNA inhibited HA-mediated RhoA activation without effect on ASMC migration. In contrast, siRNA targeting RHAMM inhibited both HA-induced migration and Rac activation. CONCLUSIONS: High-molecular weight HA independently activates RhoA and Rac through CD44 and RHAMM, respectively. HA-induced migration depends exclusively on RHAMM-mediated PI3K-dependent Rac activation.

Actins↗

PubMed2005

Association of aneurysmal and occlusive lesions in Behçet's disease.

Arterial involvement in Behçet's disease is rare, occurring in various locations with multiple clinical expressions. When Behçet's disease is associated with large arteries, lesions are usually in the form of aneurysms or occlusions. The simultaneous occurrence of these two lesions is even more unusual. We present a case of Behçet's disease in which arterial involvement included an iliac artery thrombosis and an asymptomatic aneurysm of the infrarenal abdominal aorta. Behçet's disease must be considered in the diagnosis of any unexplained inflammatory arteriopathy. Surgery is indicated for the majority of aneurysms and severe symptoms. The postoperative follow-up is based on noninvasive radiologic examinations.

Adult↗

PubMed2005

Evidence for early nasogastric tube removal after infrarenal aortic surgery: a randomized trial.

OBJECTIVE: Nasogastric tube (NGT) decompression after abdominal surgery is still largely used to prevent nausea and vomiting. However, indications are based more on practice than on studies. Moreover, prolonged NGT decompression can lead to complications. In this prospective and randomized study, we evaluated the effects of early withdrawal of NGTs in patients undergoing surgery of the infrarenal aorta. METHODS: Between October 2001 and May 2002, consecutive patients underwent scheduled infrarenal aortic operations. Patients were prospectively randomised into two groups: group 1, NGT maintenance until the passage of flatus; and group 2, NGT removal at the time of tracheal extubation. Preoperative and perioperative data were collected. The main end point was the occurrence of nausea and vomiting. Secondary end points were tolerance of NGT withdrawal and postoperative complications. Criteria were compared between groups by using Mann-Whitney or Fisher exact tests. RESULTS: Forty-six patients underwent aortic operations. Six patients were subsequently excluded from the study. Of the 40 randomized subjects, 20 patients were included in each group. Preoperative and intraoperative data were similar in both groups. There was no statistical difference between groups regarding nausea and vomiting. In group 1, the occurrence of respiratory complications was more frequent compared with group 2 (5 vs 0 complications; P = .023). There was no significant difference in intensive care unit stay, but the hospital stay was shorter in group 2 (mean, 9 +/- 3 days vs 15 +/- 9 days; P = .016). There were no differences in other adverse events. CONCLUSIONS: This study does not support a significant effect of early removal of NGTs on nausea and vomiting in patients undergoing open repair of the infrarenal aorta. However, these findings suggest that NGT maintenance increases the risk of respiratory complications and the length of hospital stay.

Aged↗

PubMed2002

Superior mesenteric artery dissection: case report.

Spontaneous dissections of the superior mesenteric artery are exceptional events because only 26 reports have been published. We present a new case, revealed with an acute abdominal syndrome. Computed tomographic angiography and arteriography allowed a rapid diagnosis and urgent surgical intervention. Progress in imagery makes diagnosis and follow-up examination easier. Surgery is indicated for acute symptomatic forms with suspicion of mesenteric ischemia. In the other cases, a simple follow-up examination may be appropriate.

Dissection↗

PubMed2002

Surgical treatment of nonaneurysmal aortic arch lesions in patients with systemic embolization.

PURPOSE: Atherosclerotic lesions of the aortic arch are potential sources of arterial embolism. Here we investigate whether surgery, with the necessary circulatory supports, can be proposed as a good option for treatment of this problem. Study of these lesions on a national scale in France has made possible the assessment for future indications of techniques and results of the surgical management of aortic arch lesions, which retrospectively proved to be embolic. METHODS: Thirty-eight patients, (19 men and 19 women) underwent surgery between 1976 and 1996 in 17 French cardiovascular surgical centers. The average age at the time of surgery was 49 +/- 12 years (range, 31 to 82 years). Atherosclerotic lesions were detected with transesophagial echocardiography (n = 19), angiography of the aortic arch (n = 16), computed tomography (n = 9), and magnetic resonance imaging (n = 10). Surgery consisted of thrombectomy and endarterectomy (n = 22), aortic resection and graft replacement (n = 10), and patch aortoplasty (n = 5; one thrombus disappeared spontaneously before surgery was performed). RESULTS: The average postoperative period was 30 months (range, 3 to 82 months). Contact was lost with four patients after a follow-up period of 12 months. On pathologic specimens obtained at surgery, an atherosclerotic plaque was found in 73% of the cases (n = 28). In 15% of the cases, the aorta appeared normal (n = 6) and four other types of lesion were identified: angiosarcoma (n = 1), ectasia at the insertion of the remains of the ductus arteriosus (n = 1), rupture of tunica intima (n = 1), and a fibroblastic plaque (n = 1). A thrombus was identified in 26 cases, attached to the arterial wall in 18 cases. When transesophagial echocardiographic results showed mobile lesions (n = 22), histopathologic examination of specimens allowed the detection of a thrombus in 18 cases and an atherosclerotic plaque with a mobile projection in four cases. The postoperative mortality rate was 2.6%. The morbidity rate (28.9%; n = 11) was related to neurologic complications (n = 6), vascular complications (n = 4), and infection (n = 1). Four cases (12%) were reoperated. CONCLUSION: Nonaneurysmal aortic arch lesions are a frequent and still underestimated source of stroke and peripheral embolization. Surgery with circulatory support can be recommended in good operative candidates with recurrent critical events despite medical management and with high embolic potential (young patients with no calcified plaques).

Adult↗