PubMed Health⌕ Search

Biomedical subjects

H Eyssen

Publications and source records attributed to H Eyssen.

At least 37 records · Page 2Linked to original sources
PubMed1988

Influence of a cecal volume-reducing intestinal microflora on the excretion and entero-hepatic circulation of steroids and bile acids.

From mouse fecal material we have isolated four strictly anaerobic bacteria which, when associated with germfree mice or rats, reduced the cecal volume by 80 and 60%, respectively. This cecal volume-reducing flora did not metabolize estrone-3-sulfate, taurolithocholate-3-sulfate or taurolithocholate but gnotobiotic rats associated with this particular flora (CRF-rats) excreted these compounds faster in feces plus urine than did germfree rats. The time needed for 50% excretion (t1/2) of orally administered estrone-3-sulfate was 32 h in germfree rats versus 13 h in CRF rats; for intraperitoneally injected taurolithocholate-3-sulfate the t1/2 was 63 h in germfree versus 17 h in CRF rats and for taurolithocholate the t1/2 was 199 h in germfree and 96 h in CRF rats. Association of germfree rats with the cecal volume-reducing flora did not change the cecal absorption rate of estrone-3-sulfate, but shortened the 50% small intestinal transit time of [14C]PEG from 10 to 3 h; a value also found in conventional rats. These results stress the important influence of the intestinal microflora on the absorption and excretion of steroids via its effect on the physiology of the whole intestinal tract and point to the deficiencies inherent to the use of germfree animals in excretion studies.

Animals↗
PubMed1988

Isolation and identification of intestinal steroid-desulfating bacteria from rats and humans.

We isolated 12 strictly anaerobic steroid-3-sulfate-desulfating strains from the intestinal floras of rats and humans. Two strains (S1 and S2) of the same atypical Clostridium species and an atypical Lactobacillus strain (termed R9) were obtained from rats. The human isolates were identified as Eubacterium cylindroides (two strains, H1 and H2), Peptococcus niger (two strains, H4 and H89), and Clostridium clostridiiforme. We also isolated, from different human fecal samples, four strains of phenotypically similar asaccharolytic Bacteroides strains, H6.2a, H6.2b, H65, and H175. Aryl steroid sulfatase activity for estrogen sulfates was present in all isolates. Alkyl steroid sulfatase activity for both 3 alpha- and 3 beta-sulfates was found only in P. niger H4. The same P. niger strain and Clostridium strains S1 and S2 also possessed bile acid sulfatase activity.

Animals↗
PubMed1987

Influence of an estrone-desulfating intestinal flora on the enterohepatic circulation of estrone-sulfate in rats.

The fecal and urinary excretion of orally administered [4-14C]estrone-3-sulfate was studied in germfree (GF) rats, conventional (CV) rats and gnotobiotic rats selectively associated with estrone-desulfating and/or cecal-volume reducing microorganisms. The time required to excrete 50% of the total label recovered (t 1/2) was 22 h in CV rats vs 32 h in GF rats. Gnotobiotic rats selectively associated with a cecal volume-reducing flora (CRF rats) excreted the label even faster (t 1/2 = 13 h) than CV rats. Association of GF rats as well as CRF rats with estrone-desulfating microorganisms (termed S1 + S2 + R9 rats and CRF + S1 + S2 + R9 rats, respectively) led to a slower excretion of labeled products (t 1/2 = 38 h in S1 + S2 + R9 rats and t 1/2 = 27 h in CFR + S1 + S2 + R9 rats). Intestinal microbial desulfation also increased the relative part of the urinary excretion from 4% in GF rats to 8% in S1 + S2 + R9 rats and from 3% in CRF rats to 9% in CFR + S1 + S2 + R9 rats. We conclude that intestinal microbial desulfation enhances the enterohepatic circulation of orally administered estrone-3-sulfate.

Animals↗
PubMed1987

Systematic analysis of the long-chain components of Eubacterium lentum.

The cellular long-chain component patterns of 33 strains of Eubacterium lentum were determined by gas chromatography. Two main types of long-chain component patterns were distinguished. The first (26 strains) was characterized by saturated branched-chain fatty acids (br14:0, br15:0, br16:0 and br17:0). The second (7 strains) did not contain branched-chain fatty acids and was characterized by saturated straight-chain fatty acids (11:0, 12:0, 14:0 and 16:0). Both types contained fatty aldehydes and their respective dimethyl acetals (14ald and 14dma, 16ald and 16dma). br16dma was only found in the first type. The G + C content of the DNA (Tm) of the 33 strains varied between 63.7 and 69.1 mol %. Canonical correlation analysis distinguished three subtypes within the first main type.

Base Composition↗
PubMed1986

Age-related differences in plasmalogen content of erythrocytes from patients with the cerebro-hepato-renal (Zellweger) syndrome: implications for postnatal detection of the disease.

Phosphatidylethanolamine plasmalogen levels were determined in erythrocytes from controls and 13 patients with the cerebro-hepato-renal (Zellweger) syndrome. It was found that in Zellweger patients 20 weeks of age or younger, erythrocyte phosphatidylethanolamine plasmalogen levels were lowered whereas in older patients (except in one) normal levels were found. The results obtained suggest a close relationship between the age of the patients at sampling and the phosphatidylethanolamine plasmalogen levels in their erythrocytes. A possible explanation for these findings and the implications for the postnatal detection of Zellweger syndrome are discussed.

Brain↗
PubMed1986

Isolation of a rat intestinal Clostridium strain producing 5 alpha- and 5 beta-bile salt 3 alpha-sulfatase activity.

An unnamed sporeforming microorganism, termed Clostridium sp. strain S2, possessing bile salt sulfatase activity was isolated from rat intestinal microflora. The microorganism was a strictly anaerobic, nonmotile, gram-negative, asaccharolytic, sporeforming rod requiring CO2, vitamin K, and taurine; the guanine-plus-cytosine content of the DNA was 40.8 mol% (Tm), and the strain was tentatively classified as an atypical Clostridium species. Sulfatase activity was specific for 3 alpha-sulfate esters of 5 alpha- and 5 beta-bile salts, leaving the 3 beta-, 7 alpha-, and 12 alpha-sulfates unchanged. Strain S2 also deconjugated tauro- and glyco-conjugated bile salts and partially reduced into the corresponding 6 alpha-hydroxy bile salts. By these reactions, alpha-muricholate and beta-muricholate were more than 80% converted into hyocholate and omega-muricholate, respectively. In addition, strain S2 produced 12 alpha-hydroxysteroid dehydrogenase converting deoxycholate into 3 alpha-hydroxy-12-oxo-5 beta-cholanoate. When strain S2 was associated with gnotobiotic rats, the fecal bile salts were more than 90% desulfated and the fecal excretion of allochenodeoxycholate was five times lower than in control rats.

Animals↗
PubMed1986

Biotransformation of Unsaturated Long-Chain Fatty Acids by Eubacterium lentum.

Eubacterium lentum (33 strains) isomerized the 12-cis double bond of C(18) fatty acids with cis double bonds at C-9 and C-12 into an 11-trans double bond before reduction of the 9-cis double bond. The 14-cis double bond of homo-gamma-linolenic acid was isomerized by 29 strains into a 13-trans double bond. The same strains isomerized the 14-cis double bond of arachidonic acid into a 13-trans double bond and then isomerized the 8-cis double bond into a 7-trans double bond; the 13-cis double bond of 10-cis, 13-cis-nonadecadienoic acid was isomerized into a 12-trans double bond. None of these isomerization products was further reduced. Studies with resting cells showed optimal isomerization velocity at a linoleic acid concentration of 37.5 muM; higher concentrations were inhibitory. The pH optimum for isomerization was 7.5 to 8.5. The isomerase was inhibited by the sulfhydryl reagents iodoacetamide, bromoacetate, and N-ethylmaleimide and by the chelators EDTA and 1,10-phenanthroline.

Journal Article↗
PubMed1985

A restriction endonuclease map of Streptomyces phage VWB.

A physical map of the actinophage VWB has been constructed using the restriction endonucleases BglII, ClaI, EcoRI, EcoRV, HindIII, KpnI and SphI. Phage VWB, genome size 47.3 kb, propagates on Streptomyces venezuelae, and it can also lysogenise this species. The three BglII-generated fragments of VWB DNA were cloned in pBR322, and subsequently mapped. In this manner the restriction map of the VWB phage genome was constructed.

Bacteriophages↗
PubMed1985

Influence of microbial bile salt desulfation upon the fecal excretion of bile salts in gnotobiotic rats.

The fecal excretion of intraperitoneally injected 24-14C-labeled taurocholate (TCA), taurolithocholate (TLCA) and the respective 3-sulfate esters (TCA-3-S; TLCA-3-S), were compared in germfree (GF) rats, conventional (CV) rats, and in gnotobiotic rats associated with Clostridium Cl-8 or this same strain Cl-8 plus the bile desulfating Clostridium S1, respectively. TCA and TLCA were about two times more rapidly excreted by CV animals than by GF animals; the time required for 50% excretion of total label injected (t 1/2) was 6.6 days vs 14.9 for TCA, and 4.4 vs 8.9 for TLCA. In GF and in CV animals, TCA-3-S and TLCA-3-S were excreted more rapidly than their nonsulfated analogues; the t 1/2 values of TCA-3-S and TCA were 2.7 days vs 14.9 in GF rats, and 3.1 vs 6.6 days in CV animals. The t 1/2 values of TLCA-3-S and TLCA were 2.7 days vs 8.9 in GF rats, and 1.5 vs 4.4 days in CV rats. In gnotobiotic rats associated with Clostridium strains S1 + Cl-8, fecal bile salts were nearly 100% deconjugated and desulfated and the 50% excretion times of TCA-3-S and TLCA-3-S approximated to those of TCA and TLCA in GF animals. T 1/2 of TCA-3-S in gnotobiotic S1 + Cl-8 animals was 12.2 days vs 14.9 for TCA in GF animals. In gnotobiotic S1 + Cl-8 animals the t 1/2 of TLCA and TLCA-3-S was 12.5 and 11.0 days, respectively. These results illustrate clearly the important effect the intestinal microflora has upon the metabolic half-life of bile salts. Moreover, they demonstrate that desulfation of bile salts by the intestinal microflora takes place in intestinal segments from where a certain degree of reabsorption is still possible, and thus point to the fact that microbial desulfation is an important variable in the overall elimination of bile salts.

Animals↗
PubMed1985

Bile acid abnormalities and the diagnosis of cerebro-hepato-renal syndrome (Zellweger syndrome).

The Zellweger or cerebro-hepato-renal syndrome (CHRS) is a congenital disorder characterized by cerebral dysfunction, craniofacial dysmorphic features, transient cholestasis and renal cysts. Patients fail to thrive, and usually die in their first year of life. In some cases, a definite diagnosis on purely clinical signs might not be possible. Several biochemical abnormalities have been observed in these patients and some of them have been tested as diagnostic markers. The aim of this study is to evaluate bile acid metabolites as biochemical markers of the CHRS. From a study of 20 CHRS patients, we conclude that screening for the presence of coprostanic acids and the C-29 dicarboxylic bile acid in serum or urine is for detection of CHRS and confirmation of the diagnosis.

Bile Acids and Salts↗
PubMed1984

Specificity of bile salt sulfatase activity in man, mouse and rat intestinal microflora.

Desulfation of bile acid 3-, 7- and 12-monosulfates was studied in incubates of fecal flora of man, rat and mouse. In anaerobic incubates, the 3 alpha-sulfates of the 5 beta-bile acids chenodeoxycholic acid and cholic acid, as well as the 3 alpha-sulfate of the 5 alpha-bile acid allochenodeoxycholic acid, were desulfated and further metabolized with the formation of a variety of metabolites. Desulfation yields were low in aerobically incubated samples, and aerobic subcultures were always negative. The 7- or 12-monosulfate esters of chenodeoxycholic acid and cholic acid were not hydrolyzed, neither anaerobically nor aerobically. High numbers (10(7) per 10(9) total count) of bile salt 3-sulfatase producing bacteria were present in rat cecal contents. No desulfating bacteria were detected in the proximal or medium small intestine of the rat, whereas low numbers were found in 2 out of 5 samples from the distal small intestine. These results reflect the predominantly anaerobic character of the bile salt sulfatase producing microflora in the intestine and suggest that the intestinal microflora of man, rat and mouse do not possess bile salt 7- or 12-sulfatase activity.

Anaerobiosis↗
PubMed1984

Biotransformation of linoleic acid and bile acids by Eubacterium lentum.

Eubacterium lentum is a gram-positive, nonsporeforming, nonmotile, asaccharolytic anaerobe. In the present investigations, 3 E. lentum strains (group E) isolated from rat feces were compared with 30 E. lentum strains (groups A, B, C, and D) previously studied by Macdonald et al. (I. A. Macdonald, J. F. Jellet, D. E. Mahony, and L. V. Holdeman, Appl. Environ. Microbiol. 37:992-1000, 1979). All strains alkalized (pH 8 to 8.5) arginine-containing (2 to 15 mg/ml) culture media, and growth of the majority of the strains was stimulated by arginine. All strains converted linoleic acid into transvaccenic acid by shifting the 12,13-cis double bond of linoleic acid into an 11,12-trans(?) double bond followed by biohydrogenation of the 9,10-cis double bond. Hence, biohydrogenation of linoleic acid is a new general characteristic of E. lentum. The 33 strains were also studied for bile acid deconjugase and hydroxysteroid dehydrogenase (HSDH) activities. The 6 strains in group D were steroid inactive; the 27 strains in groups A, B, C, and E were steroid active. The steroid-active group contained bile acid deconjugase-producing strains (groups C and E, plus strain 116 in group A) and nondeconjugating strains. All nondeconjugating strains of groups A and B developed 7 alpha- and 12 alpha-HSDH activities and contained 3 alpha-HSDH-positive strains and 3 alpha-HSDH-negative strains. Deconjugating strains varied in HSDH activities.

Arginine↗
PubMed1983

Cooperative formation of omega-muricholic acid by intestinal microorganisms.

Three anaerobic bacteria, isolated from the ceca of rats and mice, converted, through a concerted mechanism, beta-muricholic acid, the predominant bile acid in germfree rats, into omega-muricholic acid. One isolate was a Eubacterium lentum strain; the second and third isolates were tentatively identified as atypical Fusobacterium sp. strains. The conversion of beta-muricholic acid into omega-muricholic acid proceeded in two steps: E. lentum oxidized the 6 beta-hydroxyl group of beta-muricholic acid to a 6-oxo group, which was reduced by either of the two other species to a 6 alpha-hydroxyl group, yielding omega-muricholic acid. This transformation occurred both in vitro and in gnotobiotic rats. Monoassociation of germfree rats with the E. lentum strain gave rise to an unidentified fecal bile acid, probably a derivative of beta-muricholic acid having a double bond in the side chain.

Animals↗
PubMed1981

Ileal dysfunction and bacterial overgrowth in patients with Crohn's disease.

The intestinal bile acid metabolism was studied in sixty-one patients with non-operated Crohn's disease (twenty-seven ileitis and thirty-four ileocolitis patients) by means of the 14C-glycocholate breath test with marker-corrected faecal analysis before and after a short course of antibiotics. The results of the combined breath and faecal analysis were compared with the data of other tests detecting bacterial overgrowth and ileal dysfunction. Fifteen of the sixty-one patients (25%) presented with a 14C excretion pattern consistent with bacterial overgrowth of the small bowel. Repetition of the combined breath and faecal analysis after antibiotic treatment revealed that concurrent ileal dysfunction was present in at least six of these fifteen patients. In twenty other patients elevated marker-corrected 14C faecal excretion indicated ileal dysfunction. Thus, the overall incidence of ileal dysfunction amounted to 26/61 (44%). The sensitivity of the bile acid breath test with marker-corrected stool analysis was comparable to that of aerobic and anaerobic jejunal cultures in twenty non-selected patients for the detection of bacterial overgrowth, and to that of chemical bile acid measurement in stools for the detection of ileal dysfunction. The bile acid breath test with faecal analysis was more sensitive than measurement of glycine-taurine ratio in bile (twenty patients) and the Schilling test.

Adolescent↗
PubMed1980

Disturbances in bile acid metabolism of infants with the Zellweger (cerebro-hepato-renal) syndrome.

The bile acid pattern in bile and serum from two infants with the cerebro-hepato-renal syndrome of Zellweger was severely disturbed. An increased concentration particularly of trihydroxycoprostanic acid and also of dihydroxycoprostanic acid could be demonstrated. A generalized mitochondrial defect could explain these increased concentrations. This hypothesis is supported by the abnormal structure of the mitochondria in the liver biopsy of one of our patients. It is possible that the abnormal bile acids contribute to the liver damage of infants with Zellweger syndrome.

Bile Acids and Salts↗
PubMed1980

Antifungal and antibacterial activities of diarylamidine derivatives.

The antifungal and antibacterial properties of a series of 70 diarylamidine derivatives were evaluated. Several of these compounds exhibited considerable antimicrobial potency. A survey of the structure-activity relationship demonstrated that minor structural variations resulted in significant changes of antimicrobial activity. In general, the structural features required for antifungal activity coincided with those required for antibacterial activity. Both the antifungal and the antibacterial properties of the diarylamidines depended on the presence and the positions, of both amidino groups, on the nature of the central bridge connecting the two aryl moieties, and on the nature of these aryl residues (preferably indole). The most active compound was evaluated for its activity against Candida albicans infection in mice.

Amidines↗