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Biomedical subjects

M Bourel

Publications and source records attributed to M Bourel.

At least 19 recordsLinked to original sources
PubMed1998

[Hepatocytes in cell therapy].

Cell-based therapy could represent an alternative treatment to orthotopic liver transplantation in acute liver failures and for the correction of genetic defects of various enzymatic functions. Several recent studies indicate that hepatocytes injected either in the spleen or in portal vein can restore liver-specific function(s) in animal model systems. Alternatively, an extracorporal hybrid bioartificial liver might provide liver-specific functions, maintain the patient alive and allow spontaneous recovery of the patient's own liver, or act as a bridge toward liver transplantation in acute liver failures. Various drawbacks of devices such as flat culture substrates, hollow-fiber bioreactors or microcarriers led us to develop a reliable extracorporeal bioartificial liver based on alginate-entrapped hepatocytes. This system was used successfully for the correction of the Gunn rat genetic defect which results in the lack of bilirubin conjugation. The development of this system for clinical purposes requires large yields of functional hepatocytes. We isolated porcine hepatocytes by collagenase perfusion of the liver and cells were immobilized within alginate beads which were subsequently inoculated in a bioreactor. Porcine hepatocytes expressed liver-functions at high levels, particularly those involved in detoxification and biotransformation processes; they were immunoisolated from immunoglobins and could be cryopreserved. This system represents a promising tool for the design of an extracorporeal bioartificial liver in human beings.

Animals↗
PubMed1996

[Cellular therapy].

Explore the source record for details and available documents.

Cell Transplantation↗
PubMed1996

[A step towards a bioartificial liver: temporary extracorporeal replacement using isolated hepatocytes].

The mortality rate of fulminant hepatic failure is about 80%. Besides orthotopic liver transplantation, specific therapies are not currently available. Indeed, not only removal of toxins is required, by means of dialysis or hemoperfusion, but specific hepatic functions must be provided to allow spontaneous liver regeneration or as a bridge before liver transplantation. Treatment with an extracorporeal bioartificial liver is an attractive approach. This system was successfully used for the correction of the Gunn rat genetic defect which results in the lack of bilirubin conjugation. The development of this system for clinical purpose requires both a large yield of functional hepatocytes and their immunoprotection in an appropriate device. We have isolated normal porcine hepatocytes by collagenase perfusion of the liver; cells are subsequently entrapped within membrane-coated alginate beads which are inoculated in a bioreactor. Plasma from an animal undergoing fulminant hepatic failure by end-to-site portocaval shunt and whole porta hepatic tightening circulates within the bioreactor. Porcine hepatocytes express liver-specific functions at high levels, particularly secretion of plasma proteins and several enzyme activities involved in the detoxication and biotransformation of xenobiotics. In addition, hepatocytes are immunoseparated from circulating immunoglobulins. Ethical concerns are discussed in the field of physiopathology, immunopathology and public health, as a prerequisite to create departments of Cell Therapy, in the near future.

Animals↗
PubMed1991

[Hemochromatosis].

The first part of this study deals with well known as well as new data on normal iron metabolism. The second part will concern Genetic Haemochromatosis, a recessively transmitted disease principally determined by a gene located on the sixth chromosome near the A locus of HLA system: phenotypic expression of the gene, clinical features, iron overload assessment, mechanism of iron toxicity, pathogenesis of iron overload. The third part considers iron overload secondary to anaemias, to chronic alcoholic liver diseases, to porphyria cutanea tarda, to chronic haemodialysis... and their relation to the Genetic Haemochromatosis. Beyond what is already well established still lies a large number of questions with answers, at this stage, uncertain or incomplete.

Hemochromatosis↗
PubMed1991

Hepatitis B virus infection markers in genetic haemochromatosis. A study of 272 patients.

Serum hepatitis B virus (HBV) infection markers were studied in 272 patients with homozygous genetic haemochromatosis complicated (n = 33) or not (n = 239) with primary liver cancer (PLC). Controls consisted of 255 029 healthy blood donors from whom age- and sex-matched control groups were extracted for statistical evaluation using the Fisher exact test. In blood donors, HBsAg was positive in 0.075% of males and 0.04% of females. This population was not screened for anti-Hbs. Anti-Hbc alone (without HBsAg) was present in 3.7% of men and 1.8% of women. In patients with genetic haemochromatosis without liver cancer (183 males, 45.6 +/- 11.3 yrs and 56 women, 48 +/- 12.4 yrs), HBsAg was found in 1.1% of men and in none of the women. Anti-HBs was present in 7.3% of males and 1.8% of females. Anti-HBc alone was found in 13% of males (p less than 0.005 vs. controls) and 2.1% of females. From male patients with primary liver cancer complicating genetic haemochromatosis (32 males, 61.7 +/- 6.8 yrs and one female), 6.2% were HBsAg positive, 3.4% were anti-HBs positive and 16.6% anti-HBc positive (p = 0.05 vs. controls). No serum HBV marker was found in the woman. In conclusion, the prevalence of HBV infection markers--especially anti-HBc--is significantly increased in patients with genetic haemochromatosis complicated or not with primary liver cancer.

Adult↗
PubMed1990

[Medicine and archaeology: comparison of methods].

Medicine and archaeology are human sciences: their diagnostic claim consists of establishing the link between the singular case and the general model. Comparing and contrasting the two processes is not limited to a game of "similarities-differences". It makes possible a finer analysis of different methods of data collection, either with or without the help of instruments, and a comparison of different ways of handling and classifying symptoms observed and documentary evidence gathered. It shows that archaeology, in contrast to medicine (with physiology and health), has as a discipline, no real precisely defined reference. It is suggested that it is in the interest of medicine and archaeology to compare their own working methods...and their imperfections.

Archaeology↗
PubMed1989

Evaluation of computed tomography in the assessment of liver iron overload. A study of 46 cases of idiopathic hemochromatosis.

The aim of the present study was to evaluate the effectiveness of single-energy computed tomography in determining iron overload in idiopathic hemochromatosis, with special reference to slightly overloaded cases. Liver attenuation was determined in 100 patients (46 cases of idiopathic hemochromatosis, 32 cases of chronic liver disease, and 22 normal controls). The iron load was determined for the first two groups by biochemical determination of liver iron concentration (performed in all but 12 subjects in the chronic liver disease group) and hepatic histologic grading. The main results for liver attenuation (upper normal limit, 72 Hounsfield units) showed that despite a high specificity (0.96), this parameter was of low sensitivity (0.63). Although mean liver attenuation in idiopathic hemochromatosis (77 +/- 14) was significantly higher than in chronic liver diseases (53 +/- 17; p less than 10(-4) and normal controls (66 +/- 3; p less than 10(-3], and despite an overall good correlation between liver attenuation and liver iron concentration (r = 0.72; p less than 10(-3], liver attenuation was unable to detect moderate iron overload. Fourteen of 18 patients with a liver iron concentration of less than 150 mumol/g dry liver wt had liver attenuation values of less than 72. Moreover, 3 of 18 subjects with a liver iron concentration of greater than 150 had a liver attenuation of less than 72. Of these 17 false-negatives, only 7 could be attributed to associated steatosis. On the whole, single-energy computed tomography, when used on a routine basis for diagnosing iron overload, is of limited clinical value in idiopathic hemochromatosis due to its poor sensitivity. Hepatic histologic examination together with biochemical determination remains the most accurate means to assess liver iron.

Fatty Liver, Alcoholic↗
PubMed1989

Modulation of albumin secretion by ornithine alpha-ketoglutarate in adult rat hepatocyte cultures and a human hepatoma cell line (HepG2).

Cocultured adult rat hepatocytes and a human hepatoma cell line (HepG2) were maintained in an arginine-free medium with or without ornithine alpha-ketoglutarate. This drug increased greatly hepatocyte albumin secretion in both culture models. L-Ornithine was the component accounting for these effects since similar data were obtained by using this sole amino acid. Moreover, we observed that L-ornithine stimulation of albumin production was via polyamine synthesis. Since a correlated increase in albumin mRNA was observed, it may be postulated that ornithine alpha-ketoglutarate acts at a pretranslational level.

Albumins↗
PubMed1989

[Drugs and the culturing of hepatocytes].

Two model systems are described for studying isolated hepatocytes in vitro: pure culture for short-term designs and co-culture with epithelial rat liver cells (for long duration procedures). Acute or chronic liver toxicities are discussed as well as indirect toxicities. Examples of species differences and genetic polymorphism are shown. Data on drugs used for the treatment of liver diseases are also presented.

Cells, Cultured↗