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Biomedical subjects

O Bernard

Publications and source records attributed to O Bernard.

At least 109 records · Page 6Linked to original sources
PubMed1996

Inactivation of the P16INK4/MTS1 gene by a chromosome translocation t(9;14)(p21-22;q11) in an acute lymphoblastic leukemia of B-cell type.

We have reported previously a preliminary study of a t(9;14)(p21-22; q11) in B-cell acute lymphoblastic leukemia. This translocation had rearranged the TCRA/D locus on chromosome band 14q11 and the locus encoding the tumor suppressor gene P16INK4/MTS1 (P16) on band 9p21 (D. Duro et al., Oncogene, 11: 21-29, 1995). In the present report, the breakpoints were precisely localized on each chromosome partner. On the 14q- derivative, the sequence derived from chromosome 9 was interrupted at 1.0 kb upstream of the first exon of P16, close to a consensus recombination heptamer, CACTGTG. In addition, the chromosome 14 breakpoint was localized at the end of the TCRD2 (delta 2) segment, and 22 residues with unknown origin were present at the translocation junction. On the 9p+ derivative, chromosome 9 sequences were in continuity with those displaced onto chromosome 14, and the 14q11 breakpoint was located within TCRJA29 segment. These features are consistent with aberrant activity of the TCR gene recombinase complex. Although all three coding exons of P16 were displaced onto the chromosome 14q-derivative, no P16 transcript was detected in the leukemic cells. Because the region spanning the P16 exon 1 was not inactivated by methylation and because the other P16 allele was deleted, the implication is that the chromosome breakpoint was likely to disrupt regulatory elements involved in the normal expression of the gene. As a whole, then, our results show that translocations affecting band 9p21 can participate to the inactivation of P16, thus justifying a systematic survey of translocations of the 9p21 band in acute lymphoblastic leukemia.

Base Sequence↗
PubMed1996

Defect of multidrug-resistance 3 gene expression in a subtype of progressive familial intrahepatic cholestasis.

Disruption of the murine mdr2 (multidrug-resistance) gene, which encodes a phosphatidylcholine flippase, leads to a hepatic disorder because of loss of biliary phospholipid secretion. Among the hereditary human cholestasis, a subtype of progressive familial intrahepatic cholestasis with high gamma-glutamyltranspeptidase (GGT) serum activity shares histological, biochemical, and genetic features with mice lacking mdr2 gene expression (mdr2 -/- mice). No MDR3 (human mdr2 homolog) messenger RNA (mRNA) was detected by Northern blotting in the liver of a patient suffering from this form of PFIC, and the biliary phospholipid level in a second patient was substantially decreased. Thus, the absence of the MDR3 P-glycoprotein may be responsible for this type of PFIC, which, as in the murine model, may be due to a toxic effect of bile acids on the biliary epithelium in absence of biliary phospholipids.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1996

How valid is emergency liver transplantation for acute liver necrosis in patients with multiple-organ failure?

Multiple-organ failure (MOF), defined as the failure of initially uninvolved organs, is the final step of definitive and massive liver necrosis. Emergency liver transplantation (ELT) has radically modified the outcome of acute liver failure and early primary graft failure, but the results of ELT in cases of MOF are unknown. From May 1988 to June 1993, 243 patients underwent a liver transplantation (LT). Thirty-seven patients (15.2%) who had an acute liver necrosis complicated by a MOF underwent an ELT. Twenty-one patients were children. An emergency retransplantation was performed in 16 patients. Three or 4 organ-system failures (OSF) were present in 13 patients. Before ELT, the mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 26.3 +/- 5.1. Six-month and 1-year survival rates were 37.8% and 25.9%, respectively, after ELT complicated by MOF, and 78% and 73.5%, respectively, in other cases of LT. Twenty-six patients had surgical complications (70%), whereas thirty-one patients had medical complications (84%). Twenty-two patients died during the postoperative period (60%). Before ELT, infection (P < .05), cardiovascular failure (P < .03), and more than two OSF (P < .05) were more frequent in patients who died after intervention. The APACHE II score (P < .05) and the length of stay in the intensive care unit before ELT (P < .05) were lower among survivors. In the context of liver allograft shortage, our results suggest that an ELT should not be performed in patients with cardiac failure, more than two OSF, or an APACHE II score higher than 30.

Acute Disease↗
PubMed1996

[Vitamin A poisoning revealed by hypercalcemia in a child with kidney failure].

BACKGROUND: Patients with chronic renal failure are at risk of vitamin A intoxication, a risk that must be evoked when unexplained hypercalcemia occurs. CASE REPORT: An 8 year-old boy with Alagille syndrome and chronic renal failure was admitted because of general deterioration, and bone pain. Severe hypercalcemia (3.9 mmol/L) was present. Serum phosphate, parathyroid hormone and 25 OH D3 levels were normal; 1-25 (OH)2 D3 levels were undetectable. Hypercalcemia was attributed to vitamin A intoxication, due to the administration of a mean daily dose of 12000 IU of vitamin A for at least 2 years. The diagnosis was confirmed by high plasma levels of retinol (1475 micrograms/L). Hypercalcemia only partially responded to treatment with bisphosphonates, calcitonin and dialysis with low calcium dialysate. Serum vitamin A levels remained elevated one month after vitamin A withdrawal. The boy died two months after admission from atrioventricular block. CONCLUSION: Vitamin A administration induces a high risk of intoxication in patients with chronic renal failure. Serum vitamin A concentrations are elevated in these patients, because of decreased renal metabolism of retinol, and vitamin A supplements must be avoided.

Alagille Syndrome↗
PubMed1996

Spontaneous perforation of the biliary tract in infancy: a series of 11 cases.

Eleven patients presenting with spontaneous perforation of the biliary tract were treated at Bicêtre Hospital between 1971 and 1993. Three groups were individualised, each with a different pattern of local presentation: generalised biliary peritonitis (n = 2), localised biliary peritonitis (n = 4), secondary biliary stenosis (n = 5). In each case, cholestatic jaundice developed after a postnatal symptom-free interval. Ten patients were operated on. Perforation was located in the cystic duct (n = 2), at the junction of the cystic and hepatic ducts (n = 4), in the common hepatic duct (n = 1) or common bile duct (n = 1). The site of perforation was no longer identifiable in two cases with stenosis. A cholecystectomy was performed in the 2 cases with cystic duct perforation; in the cases of lesions of the main duct, either simple external biliary drainage (n = 3) or biliary reconstruction (n = 5) was carried out. Postoperative complications included bile leak (n = 2), ascending cholangitis (n = 1), portal vein thrombosis (n = 2). Five patients were submitted to further surgery including biliary revision (n = 3), porto-systemic shunt (n = 1), and other procedures (n = 2). One infant died from postoperative sepsis; 2 were lost to follow-up, one of which probably did not survive; 4 are alive and well. Late sequelae are present in 4 children: portal hypertension (n = 1), mild residual bile duct dilatation without cholestasis (n = 1), and mild to moderate liver fibrosis (n = 2). Prompt diagnosis and appropriate treatment should improve the prognosis of this rare condition.

Bile Duct Diseases↗
PubMed1996

Neonatal cholestasis as the presenting feature in cystic fibrosis.

Between 1960 and 1994 cystic fibrosis was found in nine out of 1474 infants investigated for neonatal cholestasis. Four had delay in passing meconium. In all patients cholestatic jaundice was present during the first 48 hours and in three patients cholestasis was complete, mimicking biliary atresia. Serum cholesterol concentrations were normal in all but two children. Sweat chloride was repeatedly above 95 mmol/l in all instances. Three children had another condition enhancing the risk of cholestasis (alpha1-antitrypsin deficiency, hypopituitarism, perinatal asphyxia, and total parenteral nutrition). Liver histology displayed portal fibrosis and inflammation with bile duct proliferation; mucous plugs in bile ducts were observed in only one patient. Only one child died from cirrhosis. These results indicate that cystic fibrosis is not a major cause of neonatal cholestasis. However early signs of intestinal obstruction and low concentrations of serum cholesterol may indicate cystic fibrosis, regardless of liver histology. Neonatal cholestasis has no prognostic value concerning evolution to cirrhosis.

Cholestasis↗
PubMed1996

Deletion of the short arm of chromosome 12 is a secondary event in acute lymphoblastic leukemia with t(12;21).

Translocation t(12;21) has been described as a nonrandom event in acute lymphoblastic leukemia (ALL) in patients with deletion of the short arm of chromosome 12, using fluorescence in situ hybridization techniques. Extensive FISH experiments were performed in order to re-examine the short arm of chromosome 12 in three children with ALL, previously shown to have t(12;21). It was shown that the t(12;21) is undetectable by routine R-banding technique and that the translocated 12 looks like a cytogenetically normal chromosome 12 in the three patients. Partial 12p deletion involving the TEL locus was shown to be interstitial in one patient with 12p- by using cosmid and YAC probes. In the second patient, the 12p- chromosome was secondary to the translocation since it was observed in about one half of the metaphases analyzed with FISH. In the third patient, the region of TEL usually rearranged in the t(12;21) displayed a germline pattern by Southern blotting, at diagnosis and in relapse. A few metaphases showed associated 12p- by standard cytogenetics, only in relapse. Thus we conclude that the TEL allele not involved in t(12;21) is inconstantly lost in patients with this subtype of ALL and occurs on the 12p- chromosome. These data question the status of tumor suppressor gene hypothesized for TEL.

Blotting, Southern↗
PubMed1995

Breakpoint heterogeneity in t(10;11) translocation in AML-M4/M5 resulting in fusion of AF10 and MLL is resolved by fluorescent in situ hybridization analysis.

Ten AML-M4/M5 patients' samples containing a t(10;11) translocation, but with different cytogenetic breakpoints on chromosome 11q (11q13-23), were studied by G- and R-banding and fluorescent in situ hybridization. Southern blotting analysis, studied in five patients, revealed a rearranged MLL gene. Reverse transcription-PCR analysis carried out in six patients showed a 5' MLL-3' AF-10 fusion transcript. Fluorescent in situ hybridization studies suggested that in 8 of 10 patients, the rearrangement/fusion transcript resulted from an inversion of a part of 11q (q13q23) translocated to 10p12. In the other two patients, it is assumed that an inversion/translocation has occurred of a part of 10p to the der(11). The results suggest that the orientation of the AF-10 gene on 10p is 5' telomeric and 3' centromeric. This is the first example of opposite-oriented genes being involved in translocation to yield fusion transcripts.

Adult↗
PubMed1995

The t(10;11) translocation in acute myeloid leukemia (M5) consistently fuses the leucine zipper motif of AF10 onto the HRX gene.

The gene on chromosome 10 at band p12 (AF10), involved in the t(10;11) translocation in acute myeloid leukemia, has been identified and shown to contain conserved zinc finger and leucine zipper domains. These regions are highly homologous to the equivalent regions on AF17, the gene involved in the t(11;17) translocations. A series of adult, childhood, and infant leukemias with either simple or complex versions of the t(10;11) has been examined by Southern analysis and shown to involve rearrangement to the HRX locus. Reverse transcriptase-polymerase chain reaction from either bone marrow or peripheral blood cells showed that HRX sequence was fused to AF10 sequence in all 8 cases and subsequent sequence analysis showed an in-frame fusion between the HRX and AF10 sequence. A consistent feature of these fusions was the juxtaposition of the leucine dimerization motif of AF10 onto the NH2-terminal region of HRX. The published data suggest that a similar conclusion can be drawn about the t(11;17) translocation, implying a critical role for this motif in the chimaeric HRX protein.

Adult↗
PubMed1995

Liver transplantation in children with Alagille syndrome--a study of twelve cases.

Cholestasis associated with Alagille syndrome may, in a few cases, be extremely severe and result in major impairment in the quality of life during early childhood and end up in cirrhosis eventually. We report the results of liver transplantation in 12 children with a severe hepatic form of Alagille syndrome. All children presented with cholestatic jaundice from birth, peculiar facies, stenosis of the peripheral pulmonary artery, and posterior embryotoxon; butterfly-like vertebrae were present in 9 children. At the time of transplantation (mean age 7 years 10 months) refractory pruritus was present in 9 children, xanthoma in 11, and height and weight retardation in 11. Total serum bilirubin ranged from 116 to 322 mumol/L and total serum cholesterol from 3.5 to 29 mmol/L. Systolic right ventricular pressure was moderately raised (36 to 48 mmHg) in 5 children; mean creatinine clearance was 99 ml/min/1.73 m2. Histologic examination of the removed livers showed cirrhosis, severe annular fibrosis, and moderate portal fibrosis in 4 children each. Follow-up in the 11 survivors has ranged from 14 months to 5 1/2 years. All lead normal lives. Pruritus and xanthomas disappeared. Increase in height was observed in 8 of the 10 survivors who had growth retardation prior to transplantation. School level is normal in 4 (median age at LT: 5 yr 9 mo) and below normal in 6 (median age at OLT: 9 yr 9 mo). Liver function tests are normal in 10 children. Mean creatinine clearance is 101 ml/min/1.73 m2. These results indicate that the quality of life can be considerably improved after liver transplantation in children with a severe hepatic form of Alagille syndrome and suggest that it could be carried out before these children attend elementary school.

Alagille Syndrome↗
PubMed1995

A new type of p16INK4/MTS1 gene transcript expressed in B-cell malignancies.

Chromosome band 9p21-22 is frequently altered by nonrandom abnormalities, mainly deletions, in hemopoietic malignancies of the lymphoid lineage. We have analysed a translocation t(9;14)(p21-p22;q11) in a B-cell type acute lymphoblastic leukemia. Location of the 14q11 breakpoint within the TCR-alpha/delta locus allowed the isolation of a fusion transcript composed of a 3' segment containing part of the constant region of the TCR-alpha gene and a 5' segment from chromosome 9, designated 0.18. This 0.18 segment was also part of cDNAs isolated from two tumoral B-cell lines (RPMI-8226, Raji). In both cases, 0.18 was juxtaposed 5' to a sequence corresponding to exons 2 and 3 of the p16INK4/MTS1 gene which is located on band 9p21-22. Unexpectedly, none of the two ATG codons found in 0.18 was in phase with that of the exons 2 and 3 of p16INK4/MTS1. Furthermore, in vitro translation product of a RPMI-8226 cDNA clone generated a product that was not immunoprecipitated by antibodies specific of the C-terminal end of the p16INK4/MTS1 protein. Evidence for similar transcripts in non tumoral lymphoid B cells (unstimulated peripheral blood lymphocytes (PBL) and lymphoblastoid cell lines) were obtained by using amplimers representative of the 0.18 segment and the p16INK4/MTS1 exon 2. Altogether, these data are consistent with the existence of a new type of p16INK4/MTS1 transcript whose significance is discussed.

Base Sequence↗
PubMed1995

[Lymphoproliferative syndrome induced by Epstein-Barr virus after kidney transplantation: value of genotypic analysis].

Forty-six days after renal transplantation for inborn tubulointerstitial nephropathy, an 18-year-old man was rehospitalized for renal failure with creatinine at 200 mumol/l. There was no sign of infection and ciclosporin level was within therapeutic range. Transplant biopsy showed minor interstitial infiltration with mononucleated cells. Methylprednisolone by 10 mg/kg/d bolus did not improve renal function and OKT3 5 mg/d was substituted for ciclosporin but had to be stopped on day 8 because of a severe infectious syndrome. The patient developed fever (39 degrees C), erythemato-pultaceous pharyngitis followed by major multiple lymph node and spleen enlargement. The diagnosis of primary Epstein-Barr infection was confirmed serologically. Histology of a submaxillary lymph node reported monomorphic immunoblastic lymphoproliferation. Immunologic phenotyping showed CD19, CD20 and CD22 surface antigens characteristic of B cells and in situ Epstein-Barr hybridization was positive in 100% of the cells. Southern Blot showed an oligoclonal pattern. Ciclosporin and azathioprin were stopped and the patient was treated with corticosteroids (15 mg/d) and aciclovir given orally (3.2 g/d) for 3 months. Outcome at six months was favorable with normalization of the renal function and complete regression of the infectious syndrome. This case demonstrated the importance of molecular biology techniques for virologic and genotypic assessment of lymphomatous proliferation allowing positive aetiologic diagnosis.

Acyclovir↗
PubMed1995

bcl-2 transgene expression can protect neurons against developmental and induced cell death.

The bcl-2 protooncogene, which protects various cell types from apoptotic cell death, is expressed in the developing and adult nervous system. To explore its role in regulation of neuronal cell death, we generated transgenic mice expressing Bcl-2 under the control of the neuron-specific enolase promoter, which forced expression uniquely in neurons. Sensory neurons isolated from dorsal root ganglia of newborn mice normally require nerve growth factor for their survival in culture, but those from the bcl-2 transgenic mice showed enhanced survival in its absence. Furthermore, apoptotic death of motor neurons after axotomy of the sciatic nerve was inhibited in these mice. The number of neurons in two neuronal populations from the central and peripheral nervous system was increased by 30%, indicating that Bcl-2 expression can protect neurons from cell death during development. The generation of these transgenic mice suggests that Bcl-2 may play an important role in survival of neurons both during development and throughout adult life.

Aging↗
PubMed1995

Risk and prognostic factors of gut perforation after orthotopic liver transplantation for biliary atresia.

The aim of this study was to assess the risk and prognostic factors of gut perforation after orthotopic liver transplantation in children with biliary, atresia using univariate and stepwise regression analysis. Among 51 pediatric recipients who underwent transplantation because of biliary atresia after failure of portoenterostomy, 10 patients (20%) had 19 episodes of gut perforations after 14 transplantations. The median delay between transplantation and perforation was 13 days. These perforations were treated either by suture (n = 21) or ostomy (n = 11). The study of preoperative and perioperative variables showed that children with gut perforation were in surgery for a significantly longer period of time including a longer period of receiving hepatectomy and undergoing portal venous clamp. These children also needed large amounts of blood transfused during hepatectomy. After transplantation there was no difference regarding total steroid doses and early occurrence of cytomegalovirus disease between the two groups. Stepwise regression analysis identified three factors associated with the occurrence of gut perforation: duration of transplant operation, posttransplant intra-abdominal bleeding requiring reoperation, and early portal vein thrombosis. During the postoperative course, severe fungal infections were significantly more frequent in the gut perforation group. The 3-year patient survival rate was 70% in the group with gut perforation and was not different from the group without perforation (80%). This study shows that children with previous portoenterostomy carry a high risk of developing gut perforation after liver transplantation. This is especially true for those patients with the most difficult hepatectomies, which are responsible for the iatrogenic injury of the bowel. Other risk factors pointed out in this study were splanchnic congestion in case of prolonged portal venous clamp time or early portal vein thrombosis and repeated trauma of the bowel caused by reoperations. On the other hand, other well known risk factors, such as steroid therapy and viral diseases, were not involved in the occurrence of gut perforations in this study. Besides emergent surgical treatment, this type of complication requires aggressive therapy against fungal infections.

Biliary Atresia↗