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M Hadchouel

Publications and source records attributed to M Hadchouel.

134 records · Page 8Linked to original sources
PubMedDate not supplied

Maternal inhibition of hepatitis B surface antigen gene expression in transgenic mice correlates with de novo methylation.

Differential modifications of the genome during gametogenesis result in a functional difference between the paternal and maternal genomes at the moment of fertilization. A possible cause of this imprinting is the methylation of DNA. The insertion of foreign DNA into transgenic mice allows the tagging of regions that are differentially methylated during gametogenesis. We describe here a transgenic mouse strain in which the expression of the hepatitis B surface antigen gene is irreversibly repressed following its passage through the female germ line. This inhibition is accompanied by the methylation of all the HpaII and HhaI sites within the foreign gene, which we have shown to be integrated into a site on chromosome 13. The irreversibility reported here contrasts with what is found with other transgenic mice sequences which are reversibly methylated after passage through the male or female germ line, though in both cases methylation appears to be important in the imprinting process.

Animals↗
PubMedDate not supplied

A study of liver HBV DNA during follow-up of acute viral hepatitis in children.

Twenty-nine children with acute icteric hepatitis were classified as follows after serological tests for the agents of viral hepatitis: hepatitis B 17 patients, hepatitis A 3 patients, hepatitis A + B 1 patient, possible non-A, non-B hepatitis 8 patients. In four of these cases, hepatitis A or non-A, non-B occurred in chronic HBsAg carriers. Hepatitis B virus (HBV) DNA was present in the initial serum of 15 of the 18 patients with acute hepatitis B. About 1 year after onset, HBsAg and HBV DNA were absent in 17 of them (16 of whom developed anti-HBs) and the remaining patient became a chronic HBsAg carrier without HBV DNA in his serum. At the same time, liver biopsy samples from all 29 patients were available for HBV DNA investigation. HBV DNA sequences in the liver were never found in any patient, neither under free form nor integrated into the cellular genome. The absence of HBV DNA integration in any of the liver samples taken about 1 year after the acute phase of hepatitis B suggests that such integration is either unlikely or is transitory during the symptomatic period.

Biopsy↗
PubMedDate not supplied

[Course of chronic hepatitis related to B virus in children. Study of serum viral DNA].

Nineteen children with chronic hepatitis related to the hepatitis B virus were followed for an average of 6 years. The determination of the hepatitis B virus DNA in the serum allowed us to know the state of viral replication. Thus three groups of patients could be defined: the first in which replication remained active during the total period of follow-up; the second in which the extinction of replication was observed; the third in which replication was inactive from the beginning of the serological follow-up. Symptoms, high levels of aminotransferases and histologically aggressive lesions, sometimes with cirrhosis, were more frequent in the presence of viral DNA. During the decrease of the replication, a clear-cut and time-limited increase of serum-aminotransferase levels was often noted. After the disappearance of hepatitis B virus DNA in the serum, clinical signs could be found only in children with cirrhosis or hepatocellular carcinoma. Four cases of hepatitis with initial aggressive lesions led to persistent chronic hepatitis without viral DNA in the serum. In all but one of the patients who started with an aggressive form, viral DNA disappeared in the serum. This loss occurred later and only in 2 patients of 5 who presented initially with chronic persistent hepatitis. Thus a long period of follow-up in childhood chronic hepatitis related to B virus shows frequent inactivation of viral replication. This evolution seemed to occur earlier when the initial histological lesions were aggressive as if this aggressiveness favored the elimination of the virus and the presence of specific antibodies in the serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

[Vitamin A status in liver diseases in children. Study based on 79 hepatic biopsies].

The authors studied the vitamin A status of 79 children, 71 of whom had liver disease. Plasma levels indicate low vitamin A concentration only when they are below 10 micrograms/dl. Study of liver concentration is currently the reference to appreciate vitamin A status. These concentrations are low in children with cholestasis. The lower the liver concentration, the higher the percentage of retinol in the liver. The percentage of the various retinyl esters is however independent of liver concentrations. The authors propose a model for the regulation of vitamin A metabolism within 4 pools.

Biopsy↗