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F Savoie

Publications and source records attributed to F Savoie.

17 recordsLinked to original sources
PubMed1998

Chronic blockade of NO synthase activity induces a proinflammatory phenotype in the arterial wall: prevention by angiotensin II antagonism.

Chronic blockade of NO production induces hypertension and early occlusive and fibrotic end-stage organ damage owing to vascular lesions in the brain, kidney, and heart. In this study, we evaluated the inflammatory phenotypic changes induced in the arterial wall by chronic N(G)-nitro-L-arginine methyl ester (L-NAME) administration and the effect of an angiotensin II receptor (AT1) antagonist, irbesartan, on these changes. For this purpose, 2 groups of rats received L-NAME in the drinking water (50 mg x kg(-1) x d(-1)) for 2 months. One group received no other treatment and the other was treated with irbesartan (10 mg x kg(-1) x d(-1)). A third group (controls) received neither L-NAME nor irbesartan. After 8 weeks, plasma, aortas, and left ventricles were sampled from all 3 groups. Expression of inducible NO synthase (iNOS) was evaluated at both the mRNA (quantitative reverse transcription-polymerase chain reaction) and the protein (Western blot and immunohistochemistry) level in the aorta. Expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was evaluated by reverse transcription-polymerase chain reaction, Western immunoblotting, and immunohistochemistry; inflammatory cell infiltration by immunohistochemistry; and fibrosis by Sirius red staining. Chronic L-NAME administration induced the expression of iNOS in the aorta, which was localized in smooth muscle cells as shown by immunohistochemistry and NADPH diaphorase activity. ICAM-1 and VCAM-1 expression was also increased in aortas of L-NAME-treated rats. These phenotypic changes of the vascular wall were associated with inflammatory cell infiltration and fibrosis in the heart. All of these pathological phenomena were prevented by the angiotensin II antagonist irbesartan. The proinflammatory phenotypic changes of the vascular wall induced by blockade of NOS activity could be involved in the interaction between endothelial dysfunction and the development of arteriosclerosis.

Angiotensin II↗
PubMed1997

The rotator cuff. Commentary.

To add clinical perspective to the articles of this two-issue collection, eight prominent shoulder surgeons discuss their approach to the treatment of rotator cuff disease. There is broad agreement in many areas, however, significant controversies remain.

Adult↗
PubMed1996

Development of enzyme-linked immunoassays for human angiotensin I converting enzyme suitable for large-scale studies.

OBJECTIVE: To develop and validate a simple immunological assay for human angiotensin converting enzyme (ACE) based on monoclonal antibodies. METHODS: Microtitre plates were coated with mouse monoclonal antibody (MoAb) to human ACE (9B9) and incubated with diluted samples of human plasma. In the sandwich enzyme-linked immunosorbent assay (ELISA), the plasma ACE, bound to MoAb 9B9, was revealed using polyclonal anti-ACE antibodies and alkaline phosphatase conjugated to goat anti-rabbit immunoglobulin G. In the plate precipitation assay the ACE activity, quantitatively precipitated from human plasma by MoAb 9B9, was measured by enzymatic fluorimetric assay with p-benzyloxycarboxyl-glycyl-L-histidyl-L-leucine or p-benzyloxycarboxyl-L-phenylalanyl-L-histidyl-L-leucine as substrate, directly in the wells. RESULTS: These assays are specific for the amino-terminal domain of ACE and recognize differences in the conformations of native and recombinant ACE. The sensitivity of the sandwich ELISA was 200 pg/ml assay medium; it quantifies the ACE in 10 microliters human plasma or less. Intra- and inter-assay variability coefficients were 6.2 and 13.6%, respectively. Both variants of the assay determined the plasma ACE concentration in the presence of ACE inhibitors or EDTA. The ACE concentrations were determined by sandwich ELISA in a population of 138 middle-aged healthy Caucasian subjects. They were strongly correlated with the ACE gene insertion/deletion (I/D) polymorphism, which accounted for 20% of the variance of plasma ACE concentration in this population and 16-24% of the variance in plasma ACE activity as measured with three different enzymatic assays. CONCLUSION: The ACE concentration (but not inhibition) can be determined by this ELISA which is suitable for large-scale studies of plasma ACE levels.

Animals↗
PubMed1994

Structure-function analysis of angiotensin I-converting enzyme using monoclonal antibodies. Selective inhibition of the amino-terminal active site.

Angiotensin I-converting enzyme (ACE; kininase II) contains two very similar domains (the NH2- and COOH-terminal domains (N and C domains, respectively)), each bearing an active site. These active sites hydrolyze the same peptides, but do not have the same catalytic properties and substrate specificities. In an attempt to develop domain-specific immunological probes, two series of monoclonal antibodies (mAbs), 19 clones in all, were produced and tested against human ACE. These mAbs recognized at least nine different epitopes within three antigenic regions of the ACE molecule. Testing on wild-type recombinant ACE and several mutants with only one intact domain showed that these epitopes were all located in the N domain. None of the mAbs recognized the C domain. This particular specificity and analysis of results obtained with several polyclonal antibodies to human ACE suggest that ACE immunogenicity is determined mainly by the N domain. Two mAbs (3A5 and i2H5) recognizing epitopes from different antigenic regions of ACE inhibited the enzymatic activity of the N (but not of the C) domain. mAb 3A5 had the same inhibitory potency toward hippuryl-His-Leu, benzyloxycarbonyl-Phe-His-Leu, and angiotensin I hydrolysis, with 50% inhibition achieved at a mAb/ACE molar ratio of 6. mAb i2H5 was roughly three times more effective than mAb 3A5 inhibiting the hydrolysis of benzyloxycarbonyl-Phe-His-Leu and the natural substrates angiotensin I and bradykinin (50% inhibition at a molar ratio of 1-2), but was less effective in inhibiting hippuryl-His-Leu cleavage (50% inhibition at a molar ratio of 22-25), indicating that this substrate interacts with a specific subsite. mAb i2H5 almost completely inhibited the hydrolysis of the luteinizing hormone-releasing hormone by the isolated N domain. Both the primary carboxyl- and amino-terminal cleavages of this peptide were suppressed. This antibody suppressed the primary amino-terminal cleavage of the luteinizing hormone-releasing hormone by wild-type ACE by > 90%, indicating that this particular ACE function is mediated mainly by the N domain active site. These data provide evidence for structural differences between the two homologous domains of ACE despite their high degree of sequence homology and show that monoclonal antibodies are able to distinguish between the two active sites in ACE.

Angiotensin I↗
PubMed1992

Biochemical and physiological studies on two T-kininogen species using monoclonal antibodies.

Rat T-kininogens were characterized in plasma, urine and liver slice incubation medium in different physiological conditions using monoclonal antibodies that allow to distinguish between the two forms of T-kininogen. T-kininogen purified from the plasma of both normal and inflamed Wistar and Sprague-Dawley rats was found to contain the two forms of T-kininogen, TI and TII, separated by non-denaturing polyacrylamide gel electrophoresis. The two forms were also found in the plasma of several strains of normal and inflamed rats, except in the plasma of the Buffalo rat which contained only TII-kininogen. The two forms of T-kininogen were also found in the media in which liver slices from inflamed and non-inflamed wistar rats had been incubated. The urine T-kininogen of normal rats was chiefly TI-kininogen, but both forms were found in the urine of inflamed rats. T-kininogen in the plasma of normal and inflamed rats was further characterized by chromatography on Con A-Ultrogel. In normal plasma, we observed a ratio of non-retained to retained T-kininogen of 0.41. The retained T-kininogen was eluted as two peaks, one eluted with 45 mM and the other with 120 mM alpha-methyl-D-glucoside. The ratio of non-adsorbed to adsorbed T-kininogen in inflamed Wistar rat plasma was 1.40 and the retained material was almost exclusively in a single peak, which eluted with 50 mM alpha-methyl-D-glucoside. The non-adsorbed and adsorbed fractions contained both forms of T-kininogen, but the protein bands in the non-retained fraction had greater mobilities on non-denaturing PAGE. SDS-PAGE analysis of T-kininogen deglycosylated by N-glycosidase F showed a major band with a molecular mass of 50 kDa, whereas the molecular mass of the native form was 66 kDa. We concluded that both forms of T-kininogen exist in the non-inflamed and the inflamed rat plasma, except for the Buffalo rat, and that T-kininogen displays a different chromatographic pattern on Con A-Ultrogel after inflammation suggesting altered glycosylation.

Amidohydrolases↗
PubMed1992

Hypertension in Dahl salt-sensitive rats: biochemical and immunohistochemical studies.

1. The renin-angiotensin and kinin-kallikrein systems of Dahl salt-sensitive and salt-resistant rats fed diets with different salt contents were analysed using biochemical and immunocytochemical techniques. 2. Blood pressure increased by 45% in salt-sensitive rats only, after 4 weeks on a high-salt diet. The plasma renin activity and plasma angiotensin II concentration remained at the same levels in salt-sensitive rats on the high-salt diet as on the normal salt diet, whereas the plasma renin activity and plasma angiotensin II concentration of salt-resistant rats fed the high-salt diet were lower. The plasma renin activity and the plasma angiotensin II concentration were elevated in both salt-resistant and salt-sensitive rats fed the salt-deficient diet but were much more elevated in salt-resistant than in salt-sensitive rats. 3. The kidney immunocytochemical data paralleled the data on plasma parameters. Salt-sensitive rats had fewer renin positive juxtaglomerular apparatuses than salt-resistant rats on the normal diet, and the increase on the sodium-deficient diet was also smaller in salt-sensitive rats. Salt-sensitive rats fed the high-salt diet and the standard diet had almost no angiotensin II immunoreactivity compared with the salt-resistant rats on the same diets. 4. The total renal kallikrein content of salt-sensitive rats was lower than that of salt-resistant rats on all three diets, as was the amount of kallikrein excreted in the urine on the standard and the high-salt diets. The differences resulted from a reduction in active kallikrein. The increase in kallikrein in salt-sensitive and salt-resistant rats on the salt-deficient diet was not significantly different. 5. There were similar changes in immunopositive kallikrein in the kidneys of salt-sensitive and salt-resistant rats with diet, with a large increase in kallikrein biosynthesis on the low-salt diet. The plasma concentration of high-molecular-mass kininogen was not significantly different in salt-sensitive and salt-resistant rats, but there was a significant increase in T-kininogen in salt-sensitive rats fed the high-salt diet. 6. In conclusion, the absence of decreases in the plasma renin activity and the plasma angiotensin II concentration in salt-sensitive rats fed the high-salt diet might partially explain the increase in blood pressure.

Angiotensin II↗
PubMed1989

Effect of sex hormones on plasma T-kininogen in the rat.

The influence of sex hormones on rat plasma T-kininogen concentration was examined. The level of T-kininogen in the post-pubertal female rat is about 3-times that of the male animal. Female rats castrated as adults or 15 days after birth, had low T-kininogen concentrations, near those of male rats. In contrast, castration of mature or immature male animals induced no change in T-kininogen. Treatment of castrated female or male rats with 17 alpha-ethinylestradiol significantly increased the T-kininogen level, whereas administration of testosterone or progesterone had no effect. The influence of estrogen was specific for T-kininogen, since plasma HMW kininogen concentration was the same in male and female rats and was not affected by castration or sex hormone treatment. T-kininogen concentration was not significantly changed in pregnant rat between the 12th and the 20th day of pregnancy, but increased after parturition. It was high in the newborn rat at birth and then decreased similarly over the next 3 weeks in males and females. It continued to decrease in the males, reaching the level of the adult rat, but it increased in the female from 3-4 weeks of age and reached the adult level at about 6-8 weeks. These data indicate that natural estrogens have a physiological influence on the plasma level of T-kininogen in female rats whereas testosterone had no effect on either male or castrated female rats. HMW kininogen is not physiologically dependent on sex hormones.

Acute-Phase Proteins↗
PubMed1988

Effect of dexamethasone on kininogen production by a rat hepatoma cell line.

T Kininogen and High Molecular Weight Kininogen were characterized in the cell culture medium of Fao cells, a highly differentiated cell line derived from the Reuber H35 rat hepatoma. Immunoreactive T Kininogen and High Molecular Weight Kininogen identified by direct and specific RIAs were indistinguishable from standard kininogens. Immunoreactive T Kininogen was further identified by HPLC analysis of T kinin released after trypsin hydrolysis of the cell culture medium. The basal release rate of T kininogen was ten-fold higher than that of High Molecular Weight Kininogen. T Kininogen was not stored within the cells contrary to High Molecular Weight Kininogen. The production of the two kininogens in the cell medium was stimulated by dexamethasone up to five times in a dose-dependent manner. The specific antiglucocorticoid compound RU 38486 did not alter the basal rate of kininogen release by Fao cells, but abolished the stimulation by dexamethasone, indicating that dexamethasone exerts a true glucocorticoid type effect.

Animals↗
PubMed1988

Differential effects of inflammation models on rat T-kininogen and rat angiotensinogen.

The effect of different experimental models of inflammation on plasma concentrations of T-kininogen and angiotensinogen was examined in the rat. T-kininogen, a major phase protein which inhibits cysteine proteinase is increased in all cases of induced inflammation: administration of lipopolysaccharide and turpentine, bilateral nephrectomy or sham-operation and intraperitoneal injection of peanut oil. Angiotensinogen, the renin-substrate, is increased by lipopolysaccharide but is decreased by turpentine. Sham-operation or peanut oil injection have no effect on angiotensinogen whereas, bilateral nephrectomy and dexamethasone increase its concentration. Therefore, angiotensinogen is regulated differently than T-kininogen during inflammation.

Angiotensinogen↗
PubMed1988

Effect of thyroidectomy on rat T-kininogen.

The thyroid state affects the inflammatory reaction; in general, thyroid hormones increase and hypothyroidism decreases the inflammatory response. T-kininogen is an acute phase protein that inhibits cysteine proteases. The influence of thyroidectomy and 3,5,3'-triiodothyronine (T3)-treatment of thyroidectomized animals was examined on rat plasma T-kininogen concentration. Thyroidectomy increased the T-kininogen level three- to fourfold. A single administration of 10 micrograms T3/100 g body wt in 7-wk postthyroidectomy rats decreased it by approximately 50%. Daily treatment with 0.5 micrograms T3/100 g body wt prevented the increases in T-kininogen. The modifications in plasma T-kininogen concentration were confirmed by high-performance liquid chromatography analysis of the plasma kinins released by trypsin. They demonstrated that T-kinin was greatly and bradykinin slightly increased after thyroidectomy and that T-kinin concentration in T3-treated thyroidectomized animals was almost restored to the control level. The ability of thyroidectomized animals to produce a higher plasma T-kininogen compared with euthyroid animals was further documented when T-kininogen production was stimulated by laparotomy. This procedure resulted in a fourfold increase in T-kininogen in thyroidectomized animals compared with controls. The increase of plasma T-kininogen level after thyroidectomy results from a more active synthesis of the protein, since liver slices from thyroidectomized rats synthesized T-kininogen at a rate about two times higher than normal rats. These data may account at least in part for the diminution of the inflammatory response observed after thyroidectomy.

Animals↗
PubMed1983

Would I-123 di-iodotyrosine provide a harmless deiodination test? Concise communication.

Defective iodotyrosine deiodinase activity may benefit from a specific treatment, thus requiring an unequivocal diagnosis. In reported cases this diagnosis has been obtained from an in vivo deiodination test making use of di-iodotyrosine (DIT) labeled either with I-131 or I-125. Dosimetric calculation indicates that such tests may result in unacceptable irradiation of the thyroid of a child wrongly suspected of having defective iodotyrosine deiodinase activity; therefore other methods are needed. The use of I-123 DIT is shown to be feasible, but even a 1:30 reduction in the thyroid dose still remains too high. Suppression of thyroid I- uptake by ClO4-, together with I-125 DIT, eliminates almost all thyroid irradiation and provides a sensitive, harmless, and rapid test.

Adolescent↗
PubMed1982

[Unusual concentrations of triiodothyronine in the serum due to anti-T3 autoantibodies].

Abnormally high T3 serum concentrations incompatible with the patients' clinical thyroid status were observed in a case of Graves' disease and in a euthyroid patient with hyperlipaemia. T3 was in the form of immune complexes precipitable by polyethyleneglycol. Specific anti-T3 autoantibodies were detected in the serum gammaglobulin fraction. The T3 affinity constants of these autoantibodies were found to be as high as 1.10(10) and 7.2.10(10)l/mol respectively. The antibodies interfered with radioimmunological T3 determination, resulting in an apparent increase of T3. However, after extraction, true T3 serum levels remained higher than expected. These findings illustrate the importance of hormone concentrations, affinity constants of binding proteins and equilibrium between free and bound forms in the resulting hormonal effect.

Adult↗
PubMed1973

Studies on mono- and diiodohistidine. I. The identification of iodohistidines from thyroidal iodoproteins and their peripheral metabolism in the normal man and rat.

The problem as to whether iodohistidines are normally biosynthetized in thyroglobulin and thyralbumin has been examined both in man and the rat. Evidence has been obtained for the first time that diiodohistidine (DIH) is present in both species in these two iodoproteins. The biosynthesis of monoiodohistidine (MIH) in the thyroglobulin of the normal rat has been confirmed and extended to rat thyralbumin and to human thyroid iodoproteins. THE IODOHISTIDINE IDENTIFICATION IS BASED ON FIVE ORIGINAL METHODS INCLUDING: (a) the preparation of stable and radioiodine-labeled iodohistidines; (b) the protection of the labile iodohistidines during the iodoprotein enzymatic hydrolysis; (c) the isolation of iodohistidines by ion-exchange resin chromatography; (d) their separation from each other and from iodinated cationic butanol-insoluble compounds by Sephadex G-10 chromatography; and (e) their purification by successive crystallizations to a constant specific activity. Iodohistidine levels (in percent of protein radioactivity from iodide given in vivo) were found comparable in man and the rat. However, the values (mean +/-SE) for thyroglobulin (MIH, 0.61+/-0.10%; DIH, 0.050+/-0.015%) and for thyralbumin (MIH, 2.61+/-0.57%; DIH, 0.28+/-0.09%) differ significantly (P < 0.05). Iodohistidines are stable during in vitro exposure to iodotyrosine dehalogenase preparations. In contrast to iodotyrosines the iodohistidines when given in vivo to man either orally or intravenously were in large part recovered in 24-h urines.

Administration, Oral↗
PubMed1973

Studies on mono- and diiodohistidine. II. Congenital goitrous hypothyroidism with thyroglobulin defect and iodohistidine-rich iodoalbumin production.

Butanol-insoluble iodinated compounds in the urine of patients with congenital goiters have been generally regarded as iodopeptides. Monoiodohistidine (MIH) and diiodohistidine (DIH) were identified from the urine of four patients with congenital goitrous hypothyroidism. From radioiodine studies, 40-70% of the urinary radioactivity was in the iodide-free fraction from which about 40% was identified as MIH and DIH by crystallizations to a constant specific activity. Iodotyrosines were simultaneously identified in the urine. However the presence of an iodotyrosine-deiodinase activity was demonstrated in the two removed goiters with a normal K(m) for MIT. In vivo iodotyrosine deiodination was normal for hypothyroid subjects. No thyroglobulin was identified in the thyroids from these patients. The major iodoprotein was iodoalbumin which, after in vivo labeling, contained 84-89% of the total soluble protein radioactivity. The thyroxine content of the goiter iodoalbumins and other iodoproteins was extremely low. Iodohistidines were identified in comparable proportions in the iodoalbumin and in the other iodoproteins isolated from each goiter. The average iodohistidine content of these proteins as crystallizable MIH and DIH was in the individual cases 15 and 4% of the in vivo incorporated radioiodine. DIH was identified in all iodoprotein fractions. The mean DIH/MIH ratios from the individual cases were 1.16 and 0.35. The corresponding DIT/MIT ratios were 3.19 and 1.45, respectively. The major consequence of this thyroglobulin defect is the iodination of inappropriate proteins (mainly albumin) resulting in low yields of thyroxine and high yields of iodohistidines. Iodohistidines from the goiter iodoproteins were not deiodinated and, at least for MIH, were quantitatively excreted in the urine of these patients. From the MIH iodoalbumin content and the MIH urinary excretion, goiter iodoalbumin turnover estimates were made and, although elevated, could not maintain a normal thyroxine secretion. The urinary excretion of iodohistidines easily demonstrated by column chromatography is offered as a test for detecting this variety of congenital goiter.

Adult↗
PubMedDate not supplied

[Quantitative aspects of iodine metabolism in one case of congenital iodotyrosine deiodinase defect (author's transl)].

In a 27 years old patient an iodotyrosine deiodinase defect was responsible for a profound hypothyroidism (T4-RIA: indetectable -- TSH: 190 microU/ml) associated with a large goiter (about 300 g). MIT and DIT secretions were measured from the urinary cumulative specific activities, and the molar MIT/DIT ratio was 2.2. The thyroidal iodine exchangeable pool was as low as 177 micrograms. In two comparable patients rendered euthyroid by Lipodol injection, total thyroidal 127I pool was around 40 mg and the MIT/DIT ratio was degraded to 7 suggesting a mild biosynthetic defect by iodine excess.

Adult↗