Biomedical subjects

Marie Brevet

Publications and source records attributed to Marie Brevet.

5 recordsLinked to original sources

PubMed2006

Constitutive activation of Stat5 promotes its cytoplasmic localization and association with PI3-kinase in myeloid leukemias.

Persistent activation of Stat5 is frequently found in hematologic neoplasms. Studies conducted with constitutively active Stat5 mutants (Stat51*6 and cS5F) have shown that deregulated Stat5 activity promotes leukemogenesis. To investigate the oncogenic properties of these mutants, we used cS5F-expressing bone marrow cells which induce a multilineage leukemia when transplanted into recipient mice. Here, we show by immunocytochemistry that cS5F is localized mainly in the cytoplasmic compartment of leukemic cells, suggesting that the transforming nature of cS5F may be associated with a cytoplasmic function. In support of this hypothesis, we found that cS5F forms a complex with the p85 subunit of the phosphatidylinositol 3-kinase (PI3-K) and the scaffolding adapter Gab2 in leukemic bone marrow cells, resulting in the activation of Akt/PKB, a crucial downstream target of PI3-K. By using transducible TAT-Gab2 or TAT-Akt recombinant proteins, we were able to demonstrate that activation of the PI3-kinase/Akt pathway by cS5F molecules through Gab2 is essential for induction of cell growth. We also found that persistently phosphorylated Stat5 in primary cells from patients with myeloid leukemias has a cytoplasmic localization. These data suggest that oncogenic Stat5 proteins exert dual transforming capabilities not only as transcriptional activators but also as cytoplasmic signaling effectors.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Colonic pseudolipomatosis: clinical, endoscopical and pathological features in nine cases.

UNLABELLED: Colonic pseudolipomatosis is a rare and benign condition. It is not well known by gastroenterologists and its pathogenesis is still unclear. METHODS: All cases of colonic pseudolipomatosis seen between February 2002 and June 2004 at the Amiens Universisty Hospital were identified and analyzed. RESULTS: During this period, 2099 colonoscopies were performed and 9 cases of colonic pseudolipomatosis were diagnosed (0.4%). Patients were all males aged from 41 to 67 (median age 52 years). They consulted for rectal bleeding (two patients), diarrhea (two patients) or abdominal pain (two patients). In three patients, colonic pseudolipomatosis was a fortuitous discovery during colonoscopy for polyp surveillance. The lesions presented as whitish and yellowish slightly elevated plaques ranging in size from a few millimeters to 4 cm. They extended over a two to 20 cm-long area, located in the right (two patients), transverse (four patients) or left colon (three patients). Microscopic examination showed empty spaces in the lamina propria measuring from 50 to 600 microm. They were negative for anti-CD31, CD34 and PS100 antibodies at immunohistochemistry and negative for Sudan black in three cases. The ultrastructural study showed in two cases round spaces containing small fibrillary protein-like deposits that might be lymph. CONCLUSION: Colonic pseudolipomatosis is rare. Its pathogenesis is not well-known but could be due to gas invasion or extravasation of lymph into lamina propria, maybe induced by mucosal lesions related to barotrauma or certain colonoscope cleaning solutions.

Abdominal Pain↗

PubMed2006

Adult Hirschsprung's disease diagnosed during forensic autopsy.

We report a case of fatal Hirschsprung's disease (HD) discovered at autopsy. A 20-year-old man collapsed at home. Emergency medical personnel found him in cardiac arrest and all resuscitative efforts failed. He had a past history of chronic constipation since infancy. Forensic autopsy revealed a megacolon full of gas and stools. Microscopic examination showed absence of ganglion cells in a short segment of the rectum and enterocolitis in the left and transverse colon. HD is rarely described in adults. In many cases, patients complained of constipation since infancy but the affection remained misdiagnosed. The relative good tolerance of the disease is usually due to a short aganglionic bowel segment. Enterocolitis is a frequent and severe complication of HD in children but is rarely described in adults. This case suggests the importance of HD diagnosis in childhood in order to avoid fatal complications with forensic consequences.

Adult↗

PubMed2005

Cholesterol crystal embolization diagnosed on bladder transurethral resection.

Cholesterol crystal embolization (CCE) is a severe systemic disorder caused by vascular migration of cholesterol crystals originating from ulcerative atherosclerotic plaques located in large arteries. We report 2 cases of CCE diagnosed on bladder transurethral resection in 2 men aged 94 and 72 years. Both patients had atherosclerosis disease. One patient had been treated by heparin 1 month before for pulmonary embolism and the other had had a coronary angiography and bypass graft surgery 5 months before for silent myocardial infarction. One patient presented with hematuria and the other with acute renal failure. Cystoscopy showed multiple papillary tumors of the bladder wall. Bladder transurethral resections showed transitional cell carcinoma with cholesterol crystals occluding the lumen of small arterioles in the submucosa. Eight cases of CCE in the bladder wall have been reported in the literature in 3 women and 5 men aged 56 to 79 years. Cholesterol crystal embolization is often discovered in the bladder wall on necropsy specimens. Only 2 cases have been fortuitously discovered on bladder transurethral resection performed for transitional cell carcinoma. Cholesterol crystal embolization in the bladder wall is often a marker of severe disease although the evolution is quite favorable in our patients, still alive 1 and 2 years after diagnosis.

Aged↗

PubMed2005

Groove pancreatitis and pancreatic heterotopia in the minor duodenal papilla.

Groove pancreatitis is a rare form of segmental chronic pancreatitis that involves the anatomic space between the head of the pancreas, the duodenum, and the common bile duct. We report 2 cases of groove pancreatitis with pancreatic heterotopia in the minor papilla. Patients were a 44-year-old woman and a 47-year-old man. Both had a past history of alcohol consumption and presented with abdominal pain, vomiting, and weight loss caused by duodenal stenosis. Abdominal computed tomography revealed thickening of the duodenal wall and enlargement of the pancreatic head in both patients. In 1 patient, ultrasound endoscopy showed a dilated duct in the head of the pancreas. Pancreaticoduodenectomy was performed to rule out pancreatic adenocarcinoma and because of the severity of the symptoms. In both cases, gross and microscopic examinations showed fibrous scar of the groove area. The Santorini duct was dilated and contained protein plugs in both patients, with abscesses in 1 of them. In both cases, there were microscopic foci of heterotopic pancreas with mild fibrosis in the wall of the minor papilla. Groove pancreatitis is often diagnosed in middle-aged alcoholic men presenting with clinical symptoms caused by duodenal stenosis. The pathogenesis of this rare entity could be because of disturbance of the pancreatic secretion through the minor papilla. Pancreatitis in heterotopic pancreas located in the minor papilla and chronic consumption of alcohol seem to be important pathogenic factors.

Adult↗