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Biomedical subjects

C Aussel

Publications and source records attributed to C Aussel.

At least 127 records · Page 7Linked to original sources
PubMed1981

Intrahepatic polyamine levels during rat liver carcinogenesis induced by N-2-fluorenylacetamide.

During a period of 200 days, the chronological changes of polyamine levels (putrescine, spermidine and spermine) were observed in the liver of adult female Sprague Dawley rats submitted to hepatocarcinogenesis by N-2-fluorenylacetamide (FAA). Three groups of 70 rats each were used: (1) Control 1: normal diet; (2) Control 2: low protein and low riboflavin diet; and (3) EXPERIMENTAL: 0.06% FAA added to the diet. No significant differences were noted for tissue levels of the three polyamines when the two control groups were compared. In contrast, considerable variations of these molecules were observed as a function of time in the FAA treated group: (a) an early and constant rise was seen in putrescine, with 3 maxima at days 10, 60 and 150. This last peak was the highest: 25 +/- 6 nmol/g (8 times the value for the controls at this time), and coincided with the appearance of cancerous lesions. (b) While spermidine levels varied during the experiment, no significant differences were noted in comparison with the control groups. Mean levels (nmol/g) were: 535 +/- 108 Control 1; 552 +/- 95 Control 2; 633 +/- 160 FAA-treated group. (c) Spermine levels were significantly lowered, with 3 minima corresponding to the putrescine maxima. The lowest minima was observed on day 60: 114 +/- 67 nmol/g, i.e., 4 times lower than the controls. This work shows that polyamine metabolism is profoundly modified during chemical carcinogenesis, but the possible effect of polyamines on tumorigenesis itself cannot be assessed at this point since modifications of polyamine levels are probably also associated with phenomena of liver necrosis and compensatory tissue proliferation observed during the experiment.

2-Acetylaminofluorene↗
PubMed1981

On the synthesis of alpha-fetoprotein during liver carcinogenesis by N-2-fluorenylacetamide and its relationships with the intracellular localization of the carcinogen.

Adult female Sprague-Dawley rats fed with 0.06% N-2-fluorenylacetamide presented an augmentation of plasma alpha-fetoprotein 2 days after the beginning of the experiment. This very early synthesis of alpha-fetoprotein was concomitant with the penetration of N-2-fluorenylacetamide detected by fluorescence microscopy, in the cytoplasm of the hepatocytes.

2-Acetylaminofluorene↗
PubMed1980

Modifications in adrenal activity during hepatocarcinogenesis by N-2-fluorenylacetamide.

During chemical hepatocarcinogenesis by N-2-fluorenylacetamide, the hormonal status of female Sprague Dawley rats is largely modified. Adrenals present a modified activity which is evidenced by an enlargement of glomerulosa and reticularis zones and a decrease of the fasciculata, while medulla remain unchanged. The level of aldosterone remain quite normal in N-2-fluorenylacetamide treated rats despite changes observed in the glomerulosa. The cortisol level was lowered in agreement with the decreased size of the fasciculata. The estradiol level was normal despite the reduced activity of the ovaries. The possibility of a participation of the reticularis zone in the regulation of the estradiol level is suggested. The possible protective action of the adrenals during hepatocarcinogenesis is discussed.

2-Acetylaminofluorene↗
PubMed1979

Changes in ovarian activity during hepatocarcinogenesis by N-2-fluorenylacetamide: role of alpha-fetoprotein.

During chemical hepatocarcinogenesis by N-2-fluorenylacetamide, the hormonal status of female Sprague Dawley rats is largely modified. Ovaries present a reduced activity which is evidenced by a decreased number of follicles and corpora lutea. The level of progesterone in N-2-fluorenylacetamide treated rats is low and agrees with the lack of corpora lutea. Conversely, estradiol level remains normal. This fact may be explained by the presence of alpha-fetoprotein, a carcino-embryonic protein which binds specifically estrogenic hormones.

2-Acetylaminofluorene↗
PubMed1979

Purification and characterization of an estrogen-binding peroxidase from human fetuses.

A peroxidase found under two forms with a molecular weight of 220,000 and 170,000 respectively, was purified from human fetuses. The purification procedure included ammonium sulfate precipitation, ion exchange chromatography, gel filtration and hydrophobic interaction chromatography. The purification factor approximated 400. These two forms of peroxidase were found to be immunologically identical as shown when utilizing immunodiffusion. They were able to bind estradiol in the presence of H2O2. This bond resisted to denaturation and solvent extraction therefore suggesting a covalent binding of estradiol to the enzyme.

Carrier Proteins↗
PubMed1978

Oestrone binding properties of nine molecular variants of rat alpha-foetoprotein.

Rat alpha-foetoprotein was separated into nine molecular variants by electrophoresis and affinity chromatography on Ricinus communis agglutinin and concanavalin-A. The nine variants are able to bind oestrone with the same capacity of one binding site per alpha-foetoprotein molecule. The association constants seem to vary with the sialic acid composition of the iso-alpha-foetoprotein.

Amniotic Fluid↗
PubMed1977

Ribonucleoprotein (RNP) soluble nuclear antigen: demonstration of its reaction with serum antibodies by counter-immunoelectrophoresis and further partial characterization.

The soluble ribonucleoprotein nuclear antigen reactive with specific antibodies present in sera from patients with Mixed Connective Tissure disease has alpha 2-beta 1 electrophoretic mobility, thus enabling its reaction with specific serum antibodies to be studied by counter-immunoelectrophoresis. Its molecular weight determined by elution from a calibrated Sephadex G-200 gel column is about 175,000. Its purification has been attempted by successive DEAE cellulose chromatography, Sephadex G-200 gel filtration and Hydroxyapatite chromatography. Polyacrylamide gel electrophoresis of RNP antigen-containing fractions showed persistent heterogeneity which could be due either to inadequate purification or to dissociation of the RNP-antigen during electrophoresis.

Antibodies, Antinuclear↗
PubMed1976

Alpha-foetoprotein and oestrogen metabolism. I. -Influence of alpha-foetoprotein on the metabolism of steroids by rat liver microsomes in vitro.

Rat alpha-foetoprotein (AFP) was shown to inhibit the formation of water soluble metabolities of oestrone and oestradiol by incubation with microsomes from rat liver in the presence of NADPH. The results support the proposal that in young animals the low activity of enzymes responsible of oestradiol metabolism may be due in part to the presence of AFP and not only to the low level of these enzymes.

Age Factors↗
PubMed1976

Alpha-fetoprotein: the major high-affinity estrogen binder in rat uterine cytosols.

Evidence is present that alpha-fetoprotein (AFP), a serum globulin, accounts mainly, if not entirely, for the high estrogen-binding properties of uterine cytosols from immature rats. By the use of specific immunoadsorbents to AFP and by competitive assays with unlabeled steroids and pure AFP, it has been demonstrated that in hypotonic cytosols AFP is present partly as free protein with a sedimentation coefficient of about 4-5 S and partly in association with some intracellular constituent(s) to form an 8S estrogen-binding entity. The AFP leads to 8S transformation results in a loss of antigenic reactivity to antibodies against AFP and a significant change in binding specificity. This change in binding specificity is manifested by an increase in binding affinity for estradiol, estriol, diethylstillbestrol, and nafoxidine ( a non-steroidal anti-estrogen), and by a concomitant decrease in estrone binding. Both the antigenic and binding properties of native AFP are recovered after dissociation of the 8S complex in 0.4 M KC1. An AFP-mediated mechanism of early intracellular events associated with estrogen entry in target cells is suggested and discussed with regard to current views on steroid action.

Animals↗