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Biomedical subjects

P Brissot

Publications and source records attributed to P Brissot.

At least 19 recordsLinked to original sources
PubMed1992

[Non surgical treatment of hepatocellular carcinoma].

During the last past years, the curative and preventive treatment of hepatocellular carcinoma (HCC) has improved. The regular follow-up of patients with chronic liver disease using ultrasound examination and serum alpha-fetoprotein determination, leads to diagnose hepatocellular carcinoma at an early stage, when curative treatment could be quite efficient. Besides surgery which has been the only hope of cure for a few patients, efficient medical procedures--ie chemoembolization, in situ radiotherapy and alcohol injection--are emerging. The place of these different therapeutic procedures is to be defined. In addition, the prevalence of hepatocellular carcinoma should decrease due to the improvement of preventive policy--ie vaccination against hepatitis B infection and familial screening for genetic hemochromatosis.

Carcinoma, Hepatocellular↗
PubMed1992

Inhibition of iron overload toxicity in rat hepatocyte cultures by pyoverdin Pf, the siderophore of Pseudomonas fluorescens.

The effect of the pyoverdin Pf (an iron chelating agent isolated and purified from Pseudomonas fluorescens CCM 2798) was studied on iron overloaded rat hepatocyte cultures. Iron overload was obtained by addition of 5-80 microM ferric nitrilotriacetate to the culture medium. Twenty-four hours after iron treatment, a significant increase in aspartate aminotransferase and lactate dehydrogenase in the culture medium was observed. This corresponded to intracellular decrease in the activity of these two enzymes and correlated with a decrease in albumin secretion and an increase in total free malondialdehyde production. The iron toxicity was inhibited by desferrioxamine B. Pyoverdin Pf added to the hepatocyte cultures served as an effective agent to prevent iron toxicity induced in overload. The observed effect of the pyoverdin Pf was as potent as that of desferrioxamine B.

Amino Acid Sequence↗
PubMed1992

Liver pathology in genetic hemochromatosis: a review of 135 homozygous cases and their bioclinical correlations.

Liver pathology was assessed in 135 patients with well-defined genetic hemochromatosis ranging from mild disease to severe overload. Three lesions were clearly linked to iron-overload intensity--scarce sidero-necrosis, mild inflammation, and progressive fibrosis. Iron-free foci made of typical or dysplastic hepatocytes were found in 7.4% of the cases. An original grading allowed a reliable quantification of iron and the study of cellular and lobular distribution of iron, which permitted (a) the accurate identification of a decreasing iron gradient in hepatocytes from zone 1 to zone 3 in all cases, (b) the definition of a threshold hepatocytic/mesenchymal iron ratio related to the appearance of sidero-necrosis and to the development of fibrosis, and (c) demonstration that non-iron-related factors (mainly alcoholism) could shift iron from hepatocytes to sinusoidal cells without an increase in the total liver iron amount. This study provides a dynamic view of the iron overload process and suggests that sidero-necrosis and progressive sinusoidal iron overload play a role in the development of fibrosis in human genetic hemochromatosis.

Adolescent↗
PubMed1992

Magnetic resonance imaging and assessment of liver iron content in genetic hemochromatosis.

Computed tomography (CT) scanning is not highly sensitive in the assessment of liver iron content and magnetic resonance imaging (MRI) appears to be more efficient. The aim of this study was to determine the effectiveness of MRI in the evaluation of liver iron content using a standard spin-echo technique. The study included 23 patients with genetic hemochromatosis and 24 non-iron-overloaded patients as controls. A comparison was made of: (a) MRI signal intensity of liver, spleen, paravertebral muscles and subcutaneous adipose tissue using two different spin-echo sequences (SE 500/28; SE 2000/28,56); (b) liver attenuation determined by a single energy CT scan; and (c) a biochemical determination of hepatic iron. There was a significant decrease in liver signal intensity in the genetic hemochromatosis group (256 +/- 201, mean +/- S.D.) compared with the control group (801 +/- 413, p less than 0.001), but there was no correlation with liver iron concentration. However, such a correlation was found and was even more highly significant than in CT when the ratio between the liver and another organ was taken into account. For a lower limit of liver/spleen ratio calculated at 0.46 (mean 2 S.D. in the control group), the specificity (0.96) of MRI was satisfactory, but the sensitivity (0.78) remained insufficient (MRI being unable to detect an iron overload of up to 125 mumol/g). Hopefully, these results might be improved in the near future by using more sensitive sequences such as gradient echo sequences.

Adipose Tissue↗
PubMed1992

Antioxidant and free radical scavenging activities of the iron chelators pyoverdin and hydroxypyrid-4-ones in iron-loaded hepatocyte cultures: comparison of their mechanism of protection with that of desferrioxamine.

The protective effect on iron-supplemented hepatocyte cultures of three iron chelators, pyoverdin Pa and hydroxypyrid-4-one derivatives CP20 and CP22, was compared to that of the widely known desferrioxamine B (Desferal:DFO), on the basis of two criteria: (a) their effectiveness in inhibiting free malondialdehyde (MDA) production as an index of iron-induced lipid peroxidation; and (b) their ability to reduce intracellular enzyme leakage. In view of these two markers of iron toxicity, the protective effect of these chelators was classified as follows: DFO > CP20 > or = CP22 > Pa. The mechanism of cellular protection was elucidated by investigating both the iron-chelating activity and the free radical scavenging property of these agents. As concerns the iron chelation, DFO and Pa exerted the same rank order as for cytoprotection (DFO > Pa). The free radical scavenging property toward hydroxyl radical .OH and peroxyl radical ROO. was investigated in a cell-free experimental model. The two siderophores, DFO and Pa, appeared to have a lower antiradical activity toward .OH than hydroxypyrid-4-one CP22. This .OH scavenging activity was classified as follows: CP22 >> Pa > DFO. Moreover, the chelators exhibited for the quenching of ROO. the same order of effectiveness as that observed for cellular protection: DFO > CP20 > or = CP22 > Pa. These data indicate that, in addition to the iron-chelating activity which represents the most important property for determining the protection capacity of these iron chelators, their free radical scavenging ability also must be taken into account. This direct demonstration of a strong association between the free radical scavenging activity and the protective effect of iron chelators further increases the prospects for the development and clinical applications of new oral chelating drugs.

Animals↗
PubMed1992

Liver fibrosis in genetic hemochromatosis. Respective roles of iron and non-iron-related factors in 127 homozygous patients.

A retrospective study of 127 patients with untreated homozygous genetic hemochromatosis (HGH) was conducted to evaluate the respective roles of iron overload and non-iron-related factors in the development of hepatic fibrosis in HGH. Twenty-seven percent of the patients had cirrhosis, 21% had liver fibrosis and 52% had no fibrosis (prefibrotic group). The mean value of liver iron concentration was increased significantly (p < 0.001) in cirrhotic (378 +/- 144 mumol/g dry wt.) and in fibrotic (331 +/- 168) subjects compared to prefibrotic (237 +/- 108) patients. Of 13 patients with liver iron concentration > or = 500, 12 had liver fibrosis or cirrhosis, versus 48/134 with liver iron concentration < 500. Chronic alcoholic men exhibited hepatic fibrosis or cirrhosis more frequently than non-alcoholic men (p < 0.001). Non-alcoholic men had hepatic fibrosis or cirrhosis more often than non-alcoholic women (p < 0.05). Cirrhotic and fibrotic patients were significantly older than prefibrotic patients whilst a significant correlation between age and liver iron concentration was found in younger patients only. These results suggest that the iron overload threshold necessary to induce fibrosis is modulated by non-iron-related factors such as alcoholism, sex and age. The development of fibrosis in HGH with liver iron concentration < 500 mumol/g is frequent and must lead to a search for associated non-iron-related fibrogenic factors.

Adult↗
PubMed1992

[Histochemical detection of hepatic iron. A comparative study of four stains].

Due to its specificity and easiness, Perls' stain is widely used in the histochemical assessment of liver iron content. However, it can underestimate slight iron overload, which can hamper screening for genetic hemochromatosis, especially in young people. The aim for the present study was to compare Perls' stain to three other specific iron stains (Tirmann-Schmeltzer (TRM); Hukill and Putt (HPT); Perls with Diaminobenzidine (DAB)), biochemical liver iron concentration (LIC) being used as the reference. 1) There is a significant difference between number of stained cells with TRM or DAB, compare with Perls' stain (p < 0.05). 2) Correlation (r) between histological assessment (T) and LIC was 0.39 for Perls' stain, 0.64 for TRM 0.53 for HPT and 0.64 for DAB. These data suggest that Perls' stain is not the most sensitive method for the assessment of slight iron overload. Tirmann-Schmeltzer's stain and Perls plus dAB should be preferred, especially in the screening of early liver siderosis.

Histocytochemistry↗
PubMed1991

[Metabolic cirrhosis (hemochromatosis, Wilson's disease, erythropoietic protoporphyria)].

The possibility of a metabolic chronic liver disease must always be borne in mind since in certain cases treatment can prevent the lesions from getting worse. The clinical and biochemical context should suggest either (1) genetic haemochromatosis when faced with high serum iron and ferritin levels and elevated transferrin saturation or with a suggestive clinical context (melanoderma, diabetes, hypogonadism, arthropathy, myocardiopathy); or (2) Wilson's disease in young subjects, especially in the presence of neurological and ocular signs or of haemolytic anaemia; or (3) porphyria in case of cutaneous manifestations caused by exposure to sun light. Hence the importance of full clinical examination in patients with chronic liver disease.

Hemochromatosis↗
PubMed1991

Acute infusions of bile salts increase biliary excretion of iron in iron-loaded rats.

The mechanisms of biliary excretion of iron are not well known. The aim of this study was to examine the effect of choleresis induced by several agents on biliary iron excretion in iron-loaded rats. Iron overload was obtained with a diet supplemented by 3% iron carbonyl during a 6-week period. Bile was collected with an external bile fistula. Biliary iron concentration was measured by atomic absorption spectrophotometry, and hepatic iron concentration was measured by a chemical method. Compared with controls, iron overload resulted in a 14-fold increase in hepatic iron concentration but only a 3.9-fold increase in biliary iron output. In iron-loaded rats, taurocholate infusion caused a 1.8-fold significant increase in biliary iron output. Dehydrocholate, given at the same dose, induced a significant but less pronounced (1.3-fold) increase in biliary iron output in spite of a higher bile flow. Taurochenodeoxycholate, tauroursodeoxycholate, and tauro-7-ketolithocholate induced an increase in biliary iron output similar to that observed with taurocholate. The canalicular bile salt-independent choleretic dihydroxydibutyl ether caused a significant but less pronounced increase in biliary iron output (1.4-fold). These results confirm that in iron-loaded rats biliary iron excretion is increased much less than hepatic iron concentration. They show that in iron loaded rats (a) bile salts can increase biliary iron secretion, and (b) this increase is related in part to choleresis and in part to bile salts themselves. This increase may be related to an interaction of iron with bile salt monomers and/or micelles.

Animals↗
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↗
PubMed1991

Short-term prednisolone followed by recombinant human alpha-interferon alone or combined with adenine-arabinoside in chronic hepatitis B. A prospective and randomized trial.

Twenty-nine patients with chronic hepatitis B, presenting both hepatitis B surface antigen and hepatitis B virus deoxyribonucleic acid in serum, were studied in a randomized trial treatment consisting of oral prednisolone for 28 days followed 14 days after steroid withdrawal, by either a 55 s.c. injection course of 5 M unit recombinant human alpha-interferon (group 1, 14 patients) or by adenine-arabinoside (for 21 days) combined from the fourteenth day on with the same 55 s.c. injection schedule of interferon (IFN) (group 2, 15 cases). The two groups were well matched with respect to demographic, biochemical, virological and histologic features. Significant side-effects leading to premature discontinuation of interferon were observed in only four cases in group 2 and were always reversible. Efficacy was judged on a mean follow-up period of 17 months. For the whole population, 17 patients (59%) exhibited a sustained serum hepatitis B virus deoxyribonucleic acid disappearance which corresponded to a marked improvement in liver function as demonstrated by a quasi-normalization of their serum transaminase values (ALT with n less than 22 UI/l: 23 +/- 24 vs. 139 +/- 115 before treatment; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Increase in glycosylated and nonglycosylated serum ferritin in chronic alcoholism and their evolution during alcohol withdrawal.

Increase in serum ferritin, which occurs in 40 to 70% of chronic alcoholics, remains poorly understood. We tested the hypothesis which links hyperferritinemia in chronic alcoholism not only to ferritin release from damaged liver cells, but also to increased ferritin secretion. Fifty-eight chronic alcoholic patients hospitalized for alcohol withdrawal were subdivided into three groups according to liver damage. Their serum levels of ferritin and ferritin bound to concanavalin A (ferritin Con A, which represents glycosylated, i.e., secreted ferritin) were measured serially on days 1, 7, and 11 of withdrawal and compared with a control group. The results were: (1) Total serum ferritin increased in alcoholics. Both free and Con A ferritins increased in equal proportions, the ferritin Con A to total ferritin ratio remaining unchanged. The increase was dependent on liver disease, as both free and Con A ferritins increased significantly with the severity of liver illness. Serum ferritin levels were related to iron status: it correlated with hepatic iron concentration (obtained in 19 patients); however, high ferritin values were not related to the degree of iron overload, which remained low. Finally, there was no correlation between serum ferritin and the average of alcohol consumption. (2) Both free and Con A ferritin decreased by about 40% during alcohol withdrawal. In conclusion, we have demonstrated that (1) total serum ferritin is increased in chronic alcoholism and (2) that this ferritin increase is due in part to an increase in ferritin Con A, proof of the induction of ferritin secretion by alcohol in humans.

Adult↗
PubMed1991

Iron load increases ferritin synthesis and secretion in adult human hepatocyte cultures.

In order to determine if iron load was able to stimulate specifically ferritin synthesis and secretion in adult human hepatocytes, primary cultures were submitted to increasing concentrations of ferric iron. The following results were obtained: 1. iron incorporation within the hepatocytes increased as a function of culture time and reached a high level after 48 h of treatment; 2. a dose-dependent significant stimulation of ferritin synthesis and secretion was observed when the medium iron concentration increased from 1 to 40 mumols.1(-1); 3. transferrin and albumin secretions were unaffected. The present data demonstrate that, in adult human primary cultures, iron load increases ferritin synthesis and secretion in a specific manner.

Cells, Cultured↗
PubMed1990

[Transmission of viruses (from A to E) and prevention].

Recent advances in epidemiology, virology and molecular biology have made it possible: 1) to isolate and characterize the hepatitis C and D viruses (and soon the virus of hepatitis E); 2) to develop vaccines against hepatitis A and recombinant vaccines against hepatitis B; and 3) to obtain a better understanding of the modes of transmission of the viruses and, consequently, to devise and offer an efficient prophylaxis.

Hepatitis A↗
PubMed1990

Kinetic evaluation of free malondialdehyde and enzyme leakage as indices of iron damage in rat hepatocyte cultures. Involvement of free radicals.

The present study relates to the effect of ferric iron supplementation on lipid peroxidation of adult rat hepatocyte pure cultures. Lipid peroxidation was evaluated by free malondialdehyde (MDA) using size exclusion chromatography (HPLC) as a specific and sensitive method. The ferric iron used under its complexed form with nitrilotriacetic acid (NTA) exhibited a prooxidant activity corresponding to an increase of free MDA recovery in the cells and in the culture medium. This enhancement of lipid peroxidation in the hepatocyte cultures supplemented with ferric iron was correlated with an intracellular enzyme leakage (lactate dehydrogenase and transaminase), suggesting that lipid peroxidation and enzyme release represented good parameters for cytotoxicity evaluation. The toxic effect of Fe-NTA on hepatocyte cultures was a function of the incubation time (from 0 to 48 hr) and of the concentration of ferric iron loading (i.e. 5, 20 and 100 microM). The mechanism by which Fe-NTA induced cellular damage involved free radical production, as increasing amounts of free radical scavengers corresponded to diminishing rates of both total free MDA and enzyme release. However, this reducing capacity varied from one scavenger to another, where they exhibited preferentially a decrease in lipid peroxidation or in enzyme leakage. This suggested a dissociation between the two parameters of cytotoxicity considered. Lipid peroxidation corresponding to alterations of both inner membranes and the plasma membrane, whereas enzyme release mainly corresponded to the damage of plasma membrane. Subsequently, some scavengers (superoxide dismutase, mannitol, alpha tocopherol, beta carotene) presented an intracellular activity, as they reduced mostly lipid peroxidation. Other ones (catalase, dimethylpyrroline N-oxide, thiourea) seemed essentially efficient in protecting the external plasma membrane, as shown an important decrease in enzyme leakage.

Acetates↗