Complete regression of hepatocellular carcinoma under tamoxifen.
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Biomedical subjects
M Fabre
Publications and source records attributed to M Fabre.
Aberrant development of hippocampal circuits and altered neural activity in netrin 1-deficient mice.
Diffusible factors, including netrins and semaphorins, are believed to be important cues for the formation of neural circuits in the forebrain. Here we have examined the role of netrin 1 in the development of hippocampal connections. We show that netrin 1 and its receptor, Dcc, are expressed in the developing fimbria and in projection neurons, respectively, and that netrin 1 promotes the outgrowth of hippocampal axons in vitro via DCC receptors. We also show that the hippocampus of netrin 1-deficient mice shows a misorientation of fiber tracts and pathfinding errors, as detected with antibodies against the surface proteins TAG-1, L1 and DCC. DiI injections show that hippocampal commissural axons do not cross the midline in these mutants. Instead, when axons approach the midline, they turn ventrally and form a massive aberrant projection to the ipsilateral septum. In addition, both the ipsilateral entorhino-hippocampal and the CA3-to-CA1 associational projections show an altered pattern of layer-specific termination in netrin 1-deficient mice. Finally, optical recordings with the Ca(2+) indicator Fura 2-AM show that spontaneous neuronal activity is reduced in the septum of netrin 1-mutant mice. We conclude that netrin 1 is required not only for the formation of crossed connections in the forebrain, but also for the appropriate layer-specific targeting of ipsilateral projections and for the control of normal levels of spontaneous neural activity.
Animals↗
[Primary muscular antro-pyloric hypertrophy in the adult: case report].
Primary hypertrophic antro-pyloric stenosis in adults is a misleading anatomic and radioclinical entity. It consists of hypertrophy of the internal muscular layer. Distal gastrectomy is the only effective treatment of the symptomatic form and allows a pathologic study of the gastrectomy, thus ruling out most causes of obstruction, including neoplastic ones. Its congenital origin has not been established. We report the case of a 59 year-old man who had primary hypertrophic pyloric stenosis.
Adult↗
[How fine needle aspiration biopsy make it possible to avoid extensive surgery. A case of abdominopelvic actinomycosis].
A case of abdominopelvic actinomycosis diagnosed by fine needle aspiration biopsy is reported. The patient, using an intrauterine device for five years, had a pelvic mass infiltrating the left ovary and five hepatic masses. Cytological smears prepared from an ultrasound-guided fine needle aspiration biopsy of one of the hepatic masses, showed actinomycotic granule. In the literature, few cases of abdominopelvic actinomycosis diagnosed by fine needle aspiration biopsy are reported. This affection, able to simulate a neoplasia on clinical and radiological grounds, is usually diagnosed on the histology of the surgical specimen. Ultrasound and computerized tomography allows to guide fine needle into necrotic areas where the probability to meet actinomycotic granules is maximum and so to avoid an extensive surgery.
Actinomycosis↗
[Vascular cerebral thrombosis during pregnancy and post-partum].
Pregnancy and puerperium are associated with a number of cerebrovascular conditions that may result in stroke. Those include cerebral venous thrombosis and cerebral arteries occlusions. Comparing stroke rates during pregnancy with those of non-pregnant women showed only a marginal excess risk during pregnancy and puerperium. Strokes due to cerebral venous thrombosis represent 10-20 per 100 000 deliveries in western countries. The cause of intracranial venous thrombosis is usually unknown. However, better understanding of abnormalities in coagulation leading to intravascular clotting in the early puerperium is resulting in better understanding of this disease. Nevertheless, an etiological work up should be performed, particularly when the thrombosis occurs during pregnancy. Its clinical manifestations often include focal neurological signs, seizures and headache. Alterations in consciousness occur as intracranial pressure increases. Arterial occlusions account for about 60% to 80% of cerebral ischemic lesions. A probable cause of ischemic stroke is diagnosed on the basis of clinical, biological and radiological data. Eclampsia is the main cause of nonhemorrhagic stroke. A search for rare causes of stroke linked to pregnancy such as post-partum cardiomyopathy, paradoxical embolism, choriocarcinoma, cardiac and hematological disorders may be appropriate.
Female↗
[Papillary solid tumor of the pancreas in a child: a case report].
We present a case of a papillary solid neoplasm of the head of the pancreas incidentally diagnosed after an abdominal trauma in a thirteen year old boy. Imaging features (US, CT) of the lesion were not specific enough to permit a precise diagnosis with certainty. Preoperative percutaneous needle biopsy can give presumptive evidence which may guide the treatment. Prognosis is fairly better than other pancreatic neoplasms in children (particularly pancreatoblastoma). Treatment relies only on surgery.
Adolescent↗
[Macrophage activation syndrome in primary human herpes virus-6 infection: a rare condition after liver transplantation in infants].
Human herpes virus-6 primary infection generally occurs during the first three years of childhood and is generally asymptomatic. The virus has been identified as the causal agent of exanthemum subitum in children or mononucleosis-like disease in adults, and may also cause several disorders in immunocompromised patients. We report a clinical case of acute rejection observed 29 days after orthotopic liver transplantation in a 22-month-old child associated with acute hepatitis and a hemophagocytic syndrome on day 38. Human herpes virus-6 primary infection was identified based on several virological tests: seroconversion, detection of viral DNA in bone marrow and peripheral blood after polymerase chain reaction, and detection of viral replication in peripheral blood. Tests for Epstein-Barr virus, cytomegalovirus or Parvovirus B19 infections were negative. After treatment by ganciclovir (Cymévan(R)), clinical status improved.
Acute Disease↗
Jeune syndrome and liver disease: report of three cases treated with ursodeoxycholic acid.
Three children with Jeune syndrome (asphyxiating thoracic dystrophy) had clinical and laboratory evidence of liver disease. In two patients the disease evolved to biliary cirrhosis, whereas in the third it was recognized when extensive fibrosis was developing. In the three patients, treatment with ursodeoxycholic acid appeared to control the progression of the hepatic dysfunction.
Alanine Transaminase↗
Independent regulation of adherens and tight junctions by tyrosine phosphorylation in Caco-2 cells.
To study the role of tyrosine phosphorylation in the control of intercellular adhesion of intestinal cells, we have generated several clones of Caco-2 cells that express high levels of pp60v-src only after addition of butyrate. Expression of this oncogene in cells 5 days after confluence induced beta-catenin and p120-ctn tyrosine phosphorylation, redistribution of E-cadherin to the cytosol and disassembly of adherens junctions. However, tight junctions of Caco-2 cells at 5 days after confluence were not altered by expression of pp60v-src. Similar results were obtained when Caco-2 cells were incubated with phosphotyrosine phosphatase inhibitor orthovanadate. Although addition of this compound to postconfluent cells disrupt adherens junctions, tight junctions remain unaltered, as determined measuring monolayer permeability to mannitol or hyperphosphorylation of Triton-insoluble occludin. Modifications in tight junction permeability of Caco-2 were only observed at high concentrations of orthovanadate (1 mM). Interestingly, this tyrosine phosphorylation-refractory state was achieved after confluence since early postconfluent cells (day 2) showed a limited but significant response to low doses of orthovanadate. These results suggest that tight junctions of differentiated Caco-2 cells are uncoupled from adherens junctions and are insensitive to regulation by tyrosine phosphorylation.
Caco-2 Cells↗
Paradoxical inhibition of c-myc-induced carcinogenesis by Bcl-2 in transgenic mice.
Here, we investigated changes in apoptosis during tumor progression by analyzing the effect of coexpressing various antiapoptotic genes on the multistage process of c-myc-induced hepatocarcinogenesis in transgenic mice. Whereas continuous c-myc gene overexpression in the liver led to cellular hepatocarcinoma, the coexpression of the bcl-2 gene inhibited the emergence of liver tumors, by inhibiting a pretumoral phase characterized by increased proliferation and apoptosis. This antioncogenic effect was specific to Bcl-2 and was not shared by other antiapoptotic genes such as bcl-xL and a dominant negative form of p53. Thus, we have shown that Bcl-2 can have a tumor suppressor effect in vivo on c-myc-induced hepatocarcinogenesis during the emergence of neoplastic foci.
Animals↗
Liposomal encapsulation of ganciclovir enhances the efficacy of herpes simplex virus type 1 thymidine kinase suicide gene therapy against hepatic tumors in rats.
Suicide gene therapy based on ganciclovir (GCV) metabolism by transgene herpes simplex thymidine kinase (HSV-1 TK) has been used to selectively kill proliferating cells in clinical settings such as cancer, vascular restenosis, and immunological disorders. We investigated whether encapsulation of ganciclovir (GCV) into liposomes would improve its efficacy, especially against hepatic tumors. Large unilamellar liposomes containing GCV were prepared by reversed-phase evaporation. Pharmacokinetic studies in rats showed that, compared with free GCV, the intravenous injection of liposome-encapsulated GCV (lip-GCV) led to a faster decrease in GCV plasma concentrations, but higher liver-blood ratios. After treatment of syngeneic HSV-1 TK+ liver metastases in rats, histologically active tumors were found in 95% of the transplanted lesions when physiological saline had been given and in 50% when free GCV had been given at 90.2 microM/kg twice daily. This dose is known to be insufficient for the eradication of HSV-1 TK+ tumors. In contrast, only 5% viable tumors were found in rats receiving lip-GCV at this same concentration. Average tumor volumes were 19 +/- 15, 7 +/- 9, and <1 mm3 for the control, free GCV, and lip-GCV groups, respectively. GCV-related toxicity was no longer observed. The results demonstrate that liposomal encapsulation of GCV is feasible and significantly enhances its efficacy against HSV-1 TK+ hepatic tumors.
Animals↗
In vitro analysis of the role of DCC in mucus-secreting intestinal differentiation.
The deleted in colorectal cancer (DCC) gene was initially described as a colon cancer-associated tumor suppressor gene and subsequently proposed to be involved in goblet cell differentiation, but its precise role in normal intestine physiology and in cancer remains to be established. We have analyzed DCC mRNA expression in a panel of human colorectal cancer cell lines with a variety of differentiation phenotypes by reverse transcription-polymerase chain reaction (RT-PCR) and have shown that (1) most cell lines showed lower levels of DCC mRNA than normal colonic tissue; (2) only 1 cell line lacked detectable levels of DCC mRNA expression; (3) a discrepancy was found between the detectability of RT-PCR products corresponding to the extracellular and intracellular domains of DCC; and (4) there was no association between the presence of DCC transcripts and the differentiation phenotype. Specifically, DCC was not exclusively associated with the mucus-secreting phenotype, as determined by Alcian blue staining and Northern blotting with mucin gene probes. This was further supported by immunohistochemical results on DCC product and mucins in normal colon: DCC was detected in both goblet and absorptive cells. The introduction of full-length DCC cDNA in undifferentiated HT-29 cells did not have any effect on their differentiation phenotype, as shown by morphological studies and analysis of markers for this process in colon, such as mucins, dipeptidylpeptidase IV, villin and sucrase-isomaltase. There were no effects on cell proliferation in vitro. Our results indicate that DCC is not selectively involved in the mucosecretory differentiation pathway and that it is neither sufficient nor essential for normal intestinal differentiation.
Cell Adhesion Molecules↗
In vivo hepatocyte retrovirus-mediated gene transfer through the rat biliary tract.
Delivering retroviruses targeted to hepatocytes in vivo involves the injection of retroviruses directly into the blood stream of the portal vein. The aim of this work was to delineate the conditions for delivering retroviruses in vivo by perfusing in situ the bile duct of the regenerating rat liver, and to study the hepatocyte transgene expression. At 24 hr after partial hepatectomy, during the S phase of the cell cycle, regenerating livers were perfused for 2.8+/-0.5 hr through the bile duct with 36.2+/-6.8 ml (0.3+/-01 ml/min) of fresh culture supernatant containing amphotropic recombinant retroviruses encoding the beta-galactosidase gene. The virus total titer was 1.5 x 10(8) ffu (group I) or 6.5 x 10(8) ffu (groups II and III). The hepatic artery blood flow was either maintained (groups I and II) or interrupted (group III) during bile duct perfusion. Liver biopsies taken 7 days later showed that 31.4+/-24.2% (group I), 58.7+/-23.6% (group II), and 45.1+/-21.4% (group III) of hepatocytes expressed beta-galactosidase activity, predominantly in the periportal and mediolobular zones. This study demonstrates that hepatocytes of regenerating rat livers that have entered the S phase of the cell cycle as a result of partial hepatectomy can be transduced in vivo by retroviral vectors delivered in situ by bile duct perfusion. Furthermore, the number of transduced hepatocytes closely correlated with the viral total titer and was diminished by hepatic artery blood flow occlusion during perfusion.
Animals↗
Use of von Willebrand diseased kidney as donor in a pig-to-primate model of xenotransplantation.
BACKGROUND: The coagulation process in hyperacute and delayed xenograft rejection is essential and depends upon platelet adhesion and aggregation. The initial binding of platelets to the damaged endothelium is due to the interaction of the platelet receptor glycoprotein Ib with von Willebrand factor (vWF), which is present on activated endothelial cells and bound to the subendothelial matrix. We hypothesized that the use of organs from animals with homozygous von Willebrand disease (vWD), severely deficient in vWF, might prevent the thrombosis encountered in delayed xenograft rejection. METHODS: Ten baboons were treated by extracorporeal immunoadsorption of xenoreactive natural antibodies (XNA) through the donor pig liver to inhibit hyperacute rejection and received heterotopic vWD or control pig kidney xenografts. XNA levels, coagulation, and platelet activation markers were studied, and specimens of rejected kidneys were analyzed histologically. RESULTS: Although XNA depletion was comparable in both groups, neither kidney function nor survival times of control (n=5) or vWD (n=5) porcine kidneys showed any difference. Platelet and coagulation activation was evidenced in both groups after surgery and at rejection time. Immunohistochemical analysis revealed a weak endothelial vWF immunostaining in the rejected vWD kidneys, whereas it was undetectable in the nongrafted vWD kidneys, suggesting the deposition of baboon plasma vWF on the porcine vessels. CONCLUSIONS: The use of vWD organs did not improve the survival time of grafted kidneys in this xenotransplantation model. Further studies on the use of vWD organs, in association with other therapeutic approaches, such as complement inhibition, are nevertheless necessary to evaluate the usefulness of vWF deficiency as an adjunctive therapy to decrease the coagulation process during xenograft rejection.
Animals↗
Ischemic necrosis of bile ducts complicating Schönlein-Henoch purpura.
Gastrointestinal complications of Schönlein-Henoch purpura are frequent and sometimes severe. However, there seem to be no reports of liver involvement. A child is described in whom Schönlein-Henoch purpura was complicated by bile duct lesions, resulting in biliary cirrhosis and requiring liver transplantation. At surgical removal, the liver had lesions of bile ducts and of adjacent small blood vessels in the hilum, very similar to those complicating hepatic artery thrombosis after liver transplantation. These findings suggest that Schönlein-Henoch purpura can be complicated by vasculitis of the peribiliary vessels resulting in ischemic necrosis of the bile ducts. Schönlein-Henoch purpura can be added to the list of causes of ischemic cholangiopathies.
Bile Ducts↗
Expression of collagens type I and IV, osteonectin and transforming growth factor beta-1 (TGFbeta1) in biliary atresia and paucity of intrahepatic bile ducts during infancy.
BACKGROUND/AIMS: Biliary atresia and paucity of intrahepatic bile ducts are the main causes of neonatal cholestasis leading to hepatic fibrosis. Fibrotic evolution is slow in paucity of bile ducts as compared to the rapid progression to biliary cirrhosis in biliary atresia when cholestasis persists despite hepatoportoenterostomy. Our aim was to compare the expression of collagens type I and IV, alpha-smooth muscle actin, osteonectin and transforming growth factor beta1 in biliary atresia and paucity of bile ducts. METHODS: Liver biopsies were obtained in 12 children with biliary atresia and in five with paucity of bile ducts. Collagens type I and IV, alpha-smooth muscle actin were detected with immunostaining. Collagens type I and IV, osteonectin and transforming growth factor beta1 mRNAs were detected by in situ hybridization. RESULTS: Expression of mRNA and proteins was roughly parallel. In ductular proliferation areas of biliary atresia: (1) the expression of collagens type I and IV and osteonectin was increased, and was localized to periductular myofibroblasts; (2) transforming growth factor beta1 was expressed around biliary ductules, probably in inflammatory cells, and also in biliary cells. Osteonectin expression was also increased in the lobules. In paucity of bile ducts, there was no overexpression of collagens type I and IV and transforming growth factor beta1, except in the only child with marked fibrosis. However, osteonectin expression was enhanced at the periphery of the lobules, even when fibrosis was mild or absent. CONCLUSIONS: These findings suggest that in biliary atresia ductular proliferation areas are the site of a marked production of extracellular matrix proteins in periductular myofibroblasts, probably secondary to transforming growth factor beta1 production by inflammatory cells and by biliary cells. The weak expression of transforming growth factor beta1 could explain the slow progression of fibrosis in paucity of bile ducts.
Actins↗
Peliosis hepatis with initial presentation as acute hepatic failure and intraperitoneal hemorrhage in children.
Peliosis hepatis, a condition characterized by the presence of blood-filled lacunar spaces in the liver, usually has a chronic presentation pattern and is mainly reported in adult patients in association with chronic wasting disorders and after administration of various drugs. The present report concerns two previously healthy young children in whom peliosis hepatis initially presented as acute hepatic failure and who had Escherichia coli pyelonephritis. Both patients had active intraperitoneal hemorrhage from the peliotic liver lesions, and liver ultrasonography showed multiple hypoechoic areas of different sizes, which in this context should suggest the diagnosis. One child died from hypovolemic shock and the other recovered. This study indicates that acute peliosis hepatis can be a serious life-threatening disease in children.
Acute Disease↗
[Retina where the neurons become tangled].
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