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Biomedical subjects

O Bernard

Publications and source records attributed to O Bernard.

At least 127 records · Page 7Linked to original sources
PubMed1995

Transient behavior of biological loop models with application to the Droop model.

In this paper we study the transient behavior of a class of nonlinear differential systems verifying sign conditions through the succession of extrema of the state variables. This analysis does not depend, for the main part, on the analytical formulation of the model. The possible scenarios of sequences for the extrema, are represented on a graph and can be compared with the experimental data to validate the model. An application to the Droop model illustrates this method; we obtain as a result the global stability of the equilibrium and the possible successions of the extrema.

Mathematics↗
PubMed1995

Pulmonary arteriovenous shunting in children with liver disease.

Pulmonary arteriovenous shunting (PAVS) with hypoxemia is a severe complication of cirrhosis that may regress after liver transplantation. We report PAVS in 25 children with cirrhosis and in 1 with portal vein obstruction; proof of shunting was obtained by technetium Tc 99m microaggregated albumin pulmonary scanning or a high alveoloarterial O2 gradient or both. Cyanosis or dyspnea or both occurred at ages ranging from 6 months to 14 years, earlier in children with biliary atresia and polysplenia syndrome (p < 0.01). Mean arterial oxygen tension (PaO2) was 57 mm Hg (range, 42 to 81 mm Hg) during breathing of 21% O2 and 367 mm Hg (range, 179 to 535 mm Hg) in 100% O2. Cardiac index was always raised, significantly more in children with biliary atresia and polysplenia syndrome (p < 0.01). Seven untreated children died 3 months to 8 years after the diagnosis of PAVS. Eleven underwent liver transplantation: seven are alive (follow-up, 1 to 4 years) and have no signs of PAVS. The PaO2 value during breathing of 100% O2 was > 300 mm Hg in the survivors and < 200 mm Hg in the four nonsurvivors (p < 0.01). These results indicate (1) that PAVS can occur at any age in children with portal hypertension, and that the risk is highest and earliest in children with biliary atresia and polysplenia syndrome, (2) that early liver transplantation allows regression of PAVS, and (3) that the prognosis may in part be related to the level of PaO2 while the patient is breathing 100% O2. The results indicate that systematic screening for PAVS should be part of the examination of these children.

Adolescent↗
PubMed1995

[Bilateral tumors of the testis: the role of the diagnosis of carcinoma in situ in early detection].

In a series of 540 patients with testicular germ cell tumors, the diagnosis of bilateral tumor was observed nine times. Two patients presented a simultaneous bilateral tumor and for seven others a second tumor occurred after an interval varying from 1 to 16 years. The often late discovery of the contralateral cancer sometimes requires a prolonged follow up for patients with unilateral testicular malignancy. Incidence, risk factors and therapy are discussed, in particular the anomalies in testicular migration, hypofertility, testicular atrophy and carcinoma in situ. Prevention of bilateral consecutive tumors depends on the research of carcinoma in situ thanks to testicular biopsy. A slight radiotherapy allows eradication of this tumor, whose evolution towards invading cancer is particularly high. A rigorous watch of these patients can be considered. With the absence of early detection, the treatment of the simultaneous tumor needs taking into consideration the treatment of the initial tumor. In case of a diagnosis at stage 1, observation after orchidectomy is possible without further treatment.

Adult↗
PubMed1995

Pediatric liver transplantation for Langerhans' cell histiocytosis.

Langerhans' cell histiocytosis (LCH) represents 15% to 20% of sclerosing cholangitis (SC) in children. In LCH-associated SC, a very poor response to chemotherapy has been reported, and spontaneous prognosis is very bad. Few cases of orthotopic liver transplantation (OLT) for LCH have been reported and little is known about the risk of recurrence and the effect of immunosuppression after OLT. Since 1986, five children (mean age +/- SD, 12.6 +/- 3.6 years) underwent OLT for SC complicating LCH. All patients presented with growth retardation, and severe liver disease including repeated episodes of variceal bleeding (n = 5), liver insufficiency (n = 4), jaundice (n = 5), and ascitis (n = 4). Four patients presented with previous abdominal surgery (mesocaval shunt in two and explorative laparotomy in two). OLT was performed using a whole (n = 2) or a reduced liver graft (n = 3). Pathological examination of the recipient liver showed biliary cirrhosis in all cases. Three patients are alive and well 9 to 88 months after OLT. None presented with recurrence of LCH or SC within the liver graft or in other organs. General condition (including growth and puberty) improved dramatically in the three surviving patients. Absence of recurrence after up to 7 years of follow-up after liver transplantation in our patients, as well as in all other reported cases, is encouraging and shows that OLT may be indicated in end-stage liver disease complicating LCH. Furthermore, cyclosporine may be beneficial for preventing recurrence of LCH, in which autoimmunologic mechanisms have been advocated.

Adolescent↗
PubMed1994

Genetic heterogeneity of Crigler-Najjar syndrome type I: a study of 14 cases.

Crigler-Najjar syndrome type I (CN-I) is an autosomal recessive condition characterized by severe unconjugated hyperbilirubinemia caused by the lack of bilirubin-UDP-glucuronosyltransferase (B-UGT) activity in the liver. Two B-UGTs are coded for by a gene complex (UGT1) that maps to chromosome 2q37 and that also encodes two phenol-UDP-glucuronosyltransferases. Here, we report eleven mutations (including nine novel mutations) of the B-UGT1 gene in a large series of 14 unrelated CN-I children of various geographic origins: France (seven patients: A401P, Q357X, W335X, A368T, 1223insG, A291V, K426E, K437X); Portugal (two patients: G308E); Tunisia (two patients; Q357R); Turkey (one patient: S381R); italy (two siblings: S381R). Interestingly, 6/14 mutant alleles carried by unrelated probands of French ancestry bore the A401P mutation, indicating a founder effect; this effect is probably also present in Portugal, Turkey, and Tunisia. Since mutations occurred in exons 2-5 shared by all mRNAs species of the gene, a combined deficiency of B-UGT and P-UGT was observed in the liver of five patients in whom these activities were measured. The present study confirms that CN-I is genetically heterogeneous and suggests that different founder effects are involved in Western Europe, the Middle East, and North Africa.

Crigler-Najjar Syndrome↗
PubMed1994

Evidence for defective primary bile acid secretion in children with progressive familial intrahepatic cholestasis (Byler disease).

To clarify the relationship of progressive familial intrahepatic cholestasis (Byler disease) to bile acid metabolism, we analysed, by high performance liquid chromatography, the bile acid composition of serum and bile in seven children with Byler disease and in eight control children with other cholestatic diseases. In serum, total bile acid concentration was increased in patients with Byler disease (0.30 +/- 0.05 mmol/l) and in control patients (0.21 +/- 0.08 mmol/l). Cholate (C) and chenodeoxycholate (CDC) comprised the major proportion of total bile acids in patients with Byler disease as in control patients. Hyocholate (HC) was only detected in patients with Byler disease and lithocholate was only present in control children. In bile, total bile acid concentration was very low in patients with Byler disease (1.1 +/- 1.4 mmol/l) compared to control patients (88.9 +/- 83.2 mmol/l). C and CDC were the major bile acids in control patients, whereas C and HC comprised the major proportion of bile acids in patients with Byler disease. These results suggest the existence of a defect of primary bile acid secretion in Byler disease characterized by the presence of high concentration of bile acids in serum and absence or very low concentration of bile acids in bile.

Bile↗
PubMed1994

Portal cavernoma in congenital hepatic fibrosis. Angiographic reports of 10 pediatric cases.

A retrospective pediatric study of 30 angiograms in congenital hepatic fibrosis (CHF) was undertaken to analyze the different aspects of the portal venous system in this disease. Besides the classical angiographic signs (hepatofugal veins and intrahepatic duplications), a hepatopetal venous network was present in ten children, contrasting with the patency of the portal venous system. Analysis of the medical charts for these ten patients showed that the clinical signs and outcome were similar to classical CHF. Liver biopsies were available in six cases and, in addition to the diagnostic features of CHF, demonstrated paucity or absence of portal venules. This unusual association of hepatopetal and hepatofugal collateral veins in an intrahepatic block could be explained by hypoplasia or thrombosis of portal venules. Thus, the association between hepatomegaly and hepatopetal collateral veins without portal obstruction should be suggestive of CHF.

Angiography, Digital Subtraction↗
PubMed1994

A new cause of progressive intrahepatic cholestasis: 3 beta-hydroxy-C27-steroid dehydrogenase/isomerase deficiency.

There have been a few reports of infants with severe neonatal cholestasis related to a defect in primary bile acid synthesis. To assess the importance of such deficiency among children with progressive intrahepatic cholestasis (Byler disease), screening for inborn errors in bile acid synthesis was performed by fast atom bombardment ionization-mass spectrometry of urine samples from 30 affected children. Bile acid analysis revealed a specific fast atom bombardment ionization-mass spectrometry profile for 3 beta-hydroxy-C27 steroid dehydrogenase/isomerase deficiency in five children who had jaundice, hepatosplenomegaly, and fatty stools beginning at ages ranging from 4 to 46 months. None of them had pruritus. Liver function tests showed persistently normal serum gamma-glutamyltransferase activity, low serum cholesterol and vitamin E levels, normal serum bile acid concentrations despite raised serum bilirubin levels, and decreased prothrombin time and clotting factor V. In four of the cases a similar disease was observed in siblings. Liver function returned to normal after oral ursodeoxycholic acid therapy. We conclude that 3 beta-hydroxy-C27-steroid dehydrogenase/isomerase deficiency should be considered when idiopathic cholestatic liver disease with clinical features akin to Byler disease is characterized by the association of normal serum gamma-glutamyltransferase activity, normal serum bile acid concentration, absence of pruritus, and a return to normal liver function during ursodeoxycholic acid therapy. Early identification of these children is essential because they benefit from bile acid therapy and might thus avoid the need for liver transplantation.

Alanine Transaminase↗
PubMed1994

Sclerosing cholangitis in children.

We report on 56 children with sclerosing cholangitis (SC) seen between 1972 and 1992. The first symptoms occurred at a mean age of 3.7 years; 15 infants had neonatal cholestatic jaundice. At diagnosis, cholestatic jaundice was present in 25 children, hepatomegaly in 54, splenomegaly in 41, and ascites in 12. Serum alkaline phosphatase activity was increased in 49 patients and gamma-glutamyltransferase activity in all patients tested. Most often the histopathologic findings were extensive portal fibrosis and neoductular proliferation. Cholangiography showed abnormal intrahepatic bile ducts in all children and abnormal extrahepatic bile ducts in 35 (63%). The children were separated into three groups: (1) those with SC of neonatal onset (27%); (2) those with SC of postneonatal onset associated with another disease (55%)--histiocytosis X in 14 children, immunodeficiency syndromes in 8, chronic inflammatory bowel disease or autoimmune hepatitis in 8, and congenital psoriasis in 1; and (3) those with SC of postneonatal onset without an associated disease (18%). Biliary cirrhosis was present in all but three children after 6 months to 19.3 years of follow-up. Eleven children died of portal hypertension or liver failure, and six died of a complication related to the associated disease. Fifteen children had liver transplantation; 11 of these are alive 6 months to 6 1/2 years later without recurrence of SC. The overall estimated median survival time of children with SC was 10 years from clinical onset. These results indicate that SC should be suspected in all children with a chronic cholestatic disease and increased serum gamma-glutamyl transferase activity, especially when diseases known to be associated with SC are present. The prognosis is poor, but liver transplantation should be considered except in those with severe immunodeficiency syndromes.

Adolescent↗
PubMed1994

Long-term follow-up of growth in height after successful liver transplantation.

Quantitative assessment of growth in height during the long-term follow-up of children who underwent orthotopic liver transplantation was done to allay concerns related to the progress of the children in terms of normal relationships with peers. Height curves were constructed for 119 children who received transplants at Bicêtre and Cochin Hospitals and were followed for more than 1 year. Poor linear growth was observed during the first 6 months after transplantation, during which time children received corticosteroids daily. The onset of catch-up growth was observed between 6 and 24 months after transplantation, and its magnitude did not differ between male and female patients. Both boys and girls underwent a normal pubertal growth spurt and normal development of secondary sexual characteristics. All adolescent girls had regular menstrual cycles, and one delivered a normal infant 6 years after transplantation. Patients who received transplants before the age of 2 years had poor average growth velocity by the third year after transplantation. Linear growth improved in almost all children and was not affected by the cause of the liver disease that existed before the liver transplantation except that fulminant hepatic failure was associated with poor growth. Long-term improvement of growth in height usually is obtained after liver transplantation in most children with chronic liver diseases. The use of low doses of corticosteroids, administered on an alternate-day basis, contributes to this improvement. Young age of the patient, but not the cause of the chronic liver disease, appears to influence the long-term outcome of linear growth.

Adolescent↗
PubMed1994

Liver transplantation for end-stage liver disease associated with alpha-1-antitrypsin deficiency in children: pretransplant natural history, timing and results of transplantation.

Alpha-1-antitrypsin deficiency is an inborn metabolism error which can cause emphysema and liver disease. As regards the pathophysiology of liver disease, this deficiency is poorly understood, and it is also not known why only a small proportion of Pi ZZ individuals progress towards cirrhosis and liver failure. Since there is no specific therapy for end-stage liver disease associated with alpha-1-antitrypsin deficiency, patients are considered candidates for liver transplantation. In this paper, the natural history of 16 children who underwent liver transplantation is reviewed. Fourteen patients had neonatal cholestasis as a first symptom of the disease and hepatosplenomegaly was present in all children by the age of 12 months. In 11 children, jaundice recurred, always with liver function deterioration. Two patients had a histological paucity of interlobular bile ducts and required early transplantation due to rapid progression of liver failure. At the time of pretransplant assessment, all the patients in this study had portal hypertension and seven of them had experienced at least one episode of gastrointestinal bleeding. One child had moderate intrapulmonary shunts with hypoxemia, but the others had normal spirometry and blood gases. There was no other extrahepatic complication of alpha-1-antitrypsin deficiency. Eighteen orthotopic liver transplantations were performed in 16 patients. One patient died 8 days after retransplantation due to graft necrosis. Fifteen patients (94%) were alive after a median follow-up of 22 months with an excellent quality of life, normal serum alpha-1-antitrypsin levels and without evidence of liver disease recurrence or pulmonary complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1994

Orthotopic liver transplantation in children with chronic liver disease and severe hypoxemia.

Liver transplantation has been considered until recently as an absolute contraindication in hypoxemic patients. We report our experience in nine patients who had orthotopic liver transplantation between June 1986 and June 1992. These patients had cirrhosis-related hypoxemia with intrapulmonary shunting (IPS). The arterial oxygen pressure (PaO2) on room air ranged from 47 to 78 mmHg. OLT resulted in resolution of hypoxemia and closure of IPS in five patients whose hypoxemia was higher than 60 mmHg, and in death for the remaining four patients who had severe hypoxemia (PaO2 < 60 mmHg). We conclude that hypoxemia is no longer a contraindication to liver transplantation. Patients having PaO2 levels higher than 60 mmHg should have OLT as soon as possible before reaching lower levels of PaO2, and combined lung-liver transplantation or heart-lung-liver transplantation should be discussed in patients with severe hypoxemia (PaO2 < 60 mmHg).

Adolescent↗
PubMed1994

Distinct MLL gene rearrangements associated with successive acute monocytic and lymphoblastic leukemias in the same patient.

A patient with acute monocytic leukemia (AMoL) and t(6;11)(q27;q23) developed acute lymphoblastic leukemia (ALL) and t(4;11)(q21;23), 10 months after complete remission of the AMoL. The MLL gene, normally located at band 11q23, appeared differently rearranged in the cells of these two leukemias, showing a different origin for the two malignant clones. The responsibility of etoposide, used in treatment of the AML, in the occurrence of the ALL is probable in this patient.

Adult↗