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Biomedical subjects

V Roger

Publications and source records attributed to V Roger.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Treatment of congenital dilatation of the bile ducts. Apropos of 3 cases].

Congenital dilatation of the bile duct is an uncommon lesion requiring surgical treatment. Complete excision of the diseased bile duct prevents development of carcinoma of the bile duct. We report three cases of congenital dilatation of the biliary three, each illustrating a particular aspect of the therapeutic strategy. One patient had an unusual anomaly of the pancreaticobiliary junction that required pancreaticoduodenectomy. Another patient developed carcinoma of the bile duct 15 years after an internal derivation of a choledochal cyst. The last patient had dilatations of the common and intrahepatic bile ducts associated with congenital hepatic fibrosis.

Adolescent↗
PubMed1996

[A good model of acute hepatic failure: 95% hepatectomy. Treatment by transplantation of hepatocytes].

The aim of this study was to develop in rats, a model of acute hepatic failure that mimics human fulminant hepatitis and to study the effect on survival of transplantation of isolated hepatocytes. This study showed that the mortality after 90% hepatectomy was reduced by the sole correction of hypoglycemia. On the other hand, 95% hepatectomy appeared as a reliable and reproductable model, associated with a period of hepatic coma, a deep disorder of coagulation, and a high mortality rate (> 80%) despite correction of hypoglycemia. In this model of acute hepatic failure, intraperitoneal transplantation of encapsulated isolated hepatocytes significantly reduced the mortality rate from 80% in the control groups to 31% in the transplanted group. A complete regeneration of the native liver was observed in all rats surviving. All animals survived after explantation of the hollow fibers. Well preserved hepatocytes were observed in hollow fibers two months after transplantation.

Animals↗
PubMed1994

Plasma atrial natriuretic factor and blood pressure drops during hemodialysis.

The potential role of atrial natriuretic factor (ANF) in blood pressure (BP) drops during hemodialysis (HD) has been examined in 30 patients with end-stage chronic renal failure. Echocardiographic measurements and evaluation of cardiac parasympathetic function were performed prior to HD sessions, simultaneously with hormonal determinations. The plasma ANF level was correlated with the peak value of the E wave and the Doppler index of the left ventricular preload and was more elevated in 'denervated' than in intact patients. During the HD sessions, the BP fell in 18 patients (group 1) and remained stable in 12 others (group 2), despite similar weight losses. Both groups differed by the basal values of plasma ANF, greater in group 1 than in group 2 (100.0 +/- 13.3 vs. 65.7 +/- 3.4 fmol/ml; p < 0.05). The magnitude of plasma ANF decrease was identical in both groups despite the BP decrease in group 1 at the end of the session. These results suggest that the ANF release depends not only on hemodynamics but also on cardiac innervation in dialyzed patients and that high plasma ANF levels are implied in the BP drops during HD session.

Adult↗
PubMed1994

Lysozyme and lactoperoxidase inhibit the adherence of Streptococcus mutans NCTC 10449 (serotype c) to saliva-treated hydroxyapatite in vitro.

Lysozyme, lactoperoxidase and salivary peroxidase inhibit the metabolism and growth of mutans streptococci, but any possible effects on the adherence of these bacteria are unknown. In this study the effects of lysozyme and lactoperoxidase on the adhesion of 3H-labelled Streptococcus mutans (NCTC 10449, serotype c strain) to saliva-coated hydroxyapatite were studied at pH 5.0 and 7.0. Human whole saliva was either lysozyme-depleted and centrifuged, or sterilized and dialysed to achieve no detectable lysozyme and peroxidase activities; this modified saliva was used to form experimental pellicles. The incorporation of lysozyme (50-200 micrograms/ml) to the pellicle caused a significant (p < 0.01) reduction in the adherence of S. mutans without any loss of bacterial viability. Pretreatment of either saliva-coated apatite or S. mutans cells with lysozyme did not change the results but lysozyme bound more readily to bacteria than to the experimental pellicles. Also, lactoperoxidase (10-200 micrograms/ml) reduced significantly (p < 0.001) the adherence of S. mutans but, in contrast to lysozyme, in a dose-dependent way. The strongest inhibition of adhesion was found when both saliva-coated apatite and bacteria were pretreated with lactoperoxidase. This enzyme bound to experimental pellicles in preference to streptococci. A non-specific protein control, albumin, did not block the inhibition by lysozyme or lactoperoxidase. The inhibition of adherence of a serotype c strain of S. mutans to saliva-coated hydroxyapatite is a novel antibacterial mechanism for both lysozyme and lactoperoxidase.

Albumins↗
PubMed1994

Fluoride inhibits the antimicrobial peroxidase systems in human whole saliva.

Fluoride (F-) ions at concentrations present in vivo at the plaque/enamel interface (0.05-10 mM) inhibited the activities of lactoperoxidase (LP), myeloperoxidase (MP) and total salivary peroxidase (TSP) in a pH- and dose-dependent way. The inhibition was observed only at pH < or = 6.5 and with F- concentrations > or = 0.1 mM. At pH 5.5 LP activity was inhibited by 85% and MP by 34% with 10 mM F-. TSP activity was also inhibited only at low pH (5.5) by approximately 25%. Furthermore, the generation of the actual antimicrobial agent in vivo, hypothiocyanite (HOSCN/OSCN-), of the oral peroxidase systems was inhibited by F-, again at low pH (5.0-5.5) both in buffer (by 45%) and in saliva (by 15%). This inhibition was observed only with the highest F- concentrations studied (5-10 mM). Fluoridated toothpaste (with 0.10 or 0.14% F) mixed with saliva did not inhibit TSP or HOSCN/OSCN- generation. This may have been due to the 'buffering' effect of toothpaste which did not allow salivary pH to drop below 5.9. We conclude that the F- ions in acidic fluoride products, e.g. in gels or varnishes (but not in toothpastes), may have the potential to locally inhibit the generation of a nonimmune host defense factor, HOSCN/OSCN/SCN-, produced by oral peroxidase systems. The possible clinical significance of this finding remains to be shown.

Animals↗
PubMed1992

Effects of glycerol on the growth, adhesion, and cellulolytic activity of rumen cellulolytic bacteria and anaerobic fungi.

The effect of glycerol on the growth, adhesion, and cellulolytic activity of two rumen cellulolytic bacterial species, Ruminococcus flavefaciens and Fibrobacter succinogenes subsp. succinogenes, and of an anaerobic fungal species, Neocallimastix frontalis, was studied. At low concentrations (0.1-1%), glycerol had no effect on the growth, adhesion, and cellulolytic activity of the two bacterial species. However, at a concentration of 5%, it greatly inhibited their growth and cellulolytic activity. Glycerol did not affect the adhesion of bacteria to cellulose. The growth and cellulolytic activity of N. frontalis were inhibited by glycerol, increasingly so at higher concentrations. At a concentration of 5%, glycerol totally inhibited the cellulolytic activity of the fungus. Thus, glycerol can be added to animal feed at low concentrations.

Animals↗
PubMed1992

Degradation of maize stem by two rumen fungal species, Piromyces communis and Caecomyces communis, in pure cultures or in association with cellulolytic bacteria.

Two species of rumen fungi, Piromyces (Piromonas) communis FL and Caecomyces (Sphaeromonas) communis FG10, were cultured alone or in association with the cellulolytic bacteria Ruminococcus flavefaciens or Fibrobacter succinogenes on maize stem. A kinetic study of the degradation of the substrate was then made. After 48 h of culture, all non-lignified tissues observed by scanning electron microscopy disappeared with P communis and degradation was as complete as that observed in the rumen. In contrast, C communis degraded little of the plant cell walls. The ability of P communis to more rapidly degrade maize stem was probably due to the presence of filamentous rhizoids. The extent of dry matter loss after 8 days of incubation was practically the same in all the monocultures and in the 4 cocultures. However, the rate of degradation was faster in the bacterial than in the fungal monocultures and the co-cultures. No metabolic interaction was observed.

Animals↗
PubMed1992

[Prognosis of reoperation for prosthesis dysfunction].

Between 1969 and 1990, 75 adults living in mainland France underwent reoperation for bioprosthetic valve dysfunction. The average time between the initial operation and reoperation was 65 +/- 41 months. The average age was 44 years and half of the patients were severely symptomatic (NYHA Stages III or IV in half the cases). Dysfunction of an aortic valve prosthesis was observed in 65% of cases (N = 49) and of a mitral valve prosthesis in 35% of cases (N = 26). The causes of reoperation were: 50 primary degenerations (67%), 19 infectious endocarditis (25%) and 6 perivalvular leaks (8%). Valve replacement was performed in 74 cases and suture of the sewing ring in 1 case. An associated procedure was performed in 24 cases: 12 drainage of abscess, 10 double valve replacements and 2 tricuspid valvuloplasties. The operative mortality was 9.3% and early morbidity was 46%. Univariate and multivariate analysis identified two factors predictive of operative mortality: the duration of cardiopulmonary bypass and the cardiothoracic ratio. During follow-up, which lasted 36 +/- 31 months, there were 12 deaths, 4 of cardiac failure; 4 sudden deaths, 3 deaths related to the prosthesis and 1 extracardiac death. The 6 year actuarial survival rate was 71%. The cardiothoracic ratio, the preoperative ejection fraction and the bypass time were factors predictive of global showed bypass time and the cardiothoracic ratio to be prognostic factors. The 6 year survival without cardiac events was 40%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Detection of prosthetic valve thrombosis using 111indium platelet imaging.

The diagnosis of prosthetic valve thrombosis (PVT) may be difficult in cases without valve obstruction. The aim of this study was to evaluate the diagnostic accuracy of 111indium-labelled autologous platelet imaging in the detection of PVT. We studied 41 patients with 45 prostheses, mechanical (37) or biological (8), in the mitral (26) or aortic (19) site. Mean age was 55 +/- 13 years. All these patients experienced one or several thromboembolic events (mean: 2.3 per patient). The mean interval between the last embolic event and indium test (IT) was 32 +/- 25 days. Scintigrams were recorded in two views daily for 5 days. IT showed an abnormal platelet deposition on the prosthetic area in 24 patients. Platelet half-life was 3.8 +/- 1.0 days for patients with a positive IT and 4.6 +/- 0.6 days for those with a negative IT (P less than 0.01). Anatomical data were obtained in 10 cases (surgery nine, autopsy one) 16 +/- 5 days after IT. All these patients had PVT, and IT was positive in eight cases. In the other 31 medically treated patients, recurrent embolism occurred within 12 months after IT in four cases, three of whom previously had a positive test. We conclude that IT is a useful means for detecting PVT.

Aortic Valve↗
PubMed1990

Effects of Physicochemical Factors on the Adhesion to Cellulose Avicel of the Ruminal Bacteria Ruminococcus flavefaciens and Fibrobacter succinogenes subsp. succinogenes.

Ruminococcus flavefaciens adhered instantly to cellulose, while Fibrobacter succinogenes had the highest percentage of adherent cells after about 25 min of contact between bacteria and cellulose. Adhesion of R. flavefaciens was unaffected by high concentrations of sugars (5%), temperature, pH, oxygen, metabolic inhibitors, and lack of Na. In contrast, the attachment was affected by the removal of divalent cations (Mg and Ca), the presence of cellulose derivatives (methylcellulose and hydroxyethylcellulose), and cystine. Adhesion of F. succinogenes was sensitive to low and high temperatures, high concentrations of glucose and cellobiose (5%), hydroxyethylcellulose (0.1%), redox potential, pH, lack of monovalent cations, and the presence of an inhibitor of membrane ATPases or lasalocid and monensin. Cells of F. succinogenes heated at 100 degrees C no longer were adherent. On the other hand, adhesion was insensitive to the lack of divalent cations (Mg and Ca), the presence of 2,4-dinitrophenol, tetrachlorosalicylanilide, or inhibitors of the electron transfer chains. Adhesion of F. succinogenes seems to be related to the metabolic functions of the cell. External proteins and/or cellulases themselves might play a part in the attachment process. Several mechanisms are probably involved in the adhesion of R. flavefaciens, the main one being the interaction between the large glycocalyx and the divalent cations Ca and Mg. Hydrophobic bonds and enzymes may also be involved.

Journal Article↗
PubMed1990

[Semi-invasive aspergillosis with involvement of the thoracic wall cured by itraconazole].

Pulmonary aspergillosis invading the thoracic wall is rare and of sombre prognosis. We report the case of a 49-year old man who developed a pulmonary aspergilloma some time after lung resection and radiotherapy for bronchial adenocarcinoma. Surgical excision of the aspergilloma was followed by sternal, then costal aspergillosis. Conventional surgery and antifungal therapy failed, and the lesion stubbornly followed a chronic course until itraconazole therapy was instituted, resulting in a complete cure which still persists nearly 4 years after withdrawal of any chemotherapy.

Antifungal Agents↗
PubMed1990

[Importance of masseter insertion surface in different mammal groups].

The objective of this study is to compare the strength of the masseter muscle in various mammals by calculating the ratio between insertion area of the masseter and total mandibular surface. We will also determine the factors capable of modifying the insertion area of this masticatory muscle.

Anatomy, Comparative↗
PubMed1987

[Traumatic tricuspid insufficiency. Apropos of a case treated by conservative surgery].

Traumatic tricuspid insufficiency is a rare condition which raises the problem of when and how should its surgical correction be performed. Its diagnosis has been considerably facilitated by echocardiography. We report a case of traumatic tricuspid insufficiency with extensive lesions of the tricuspid valve system, which was diagnosed after a 15-year period without functional signs. Echocardiography and Doppler ultrasounds provided very accurate information on the lesions. Optimal correction was obtained by conservative surgery. The excellent results observed at short and medium term suggest that surgical indications should be extended.

Accidents, Traffic↗
PubMed1987

[Doppler measurement of transvalvular gradients. Simultaneous Doppler-catheterization recordings on 78 patients].

Several studies have demonstrated the value of Doppler ultrasound as a means of measuring gradients across cardiac valves. However, in view of sudden variations in cardiac output gradients should be measured simultaneously by Doppler and catheterization in order to validate the former method and determine its accuracy. We conducted a prospective study with simultaneous recordings in 78 patients with aortic valve stenosis (33) or mitral valve stenosis (19) or cardiac valve prosthesis (26). Mean age of the patients was 55 +/- 14 years, and 50% of them were male. Subjects with pure or predominant regurgitation were excluded from the study. In the whole of the population studied, correlation between Doppler ultrasound and haemodynamics was very good with r = 0.98, p less than 0.001 for maximum gradient and r = 0.96, p less than 0.001 for mean gradient. The perfect simultaneity of the haemodynamic and ultrasonic recordings was confirmed by comparing the duration of gradients measured by the two methods (r = 0.996, p less than 0.001). There also was very close correlation between ultrasounds and catheter in patients with mitral stenosis (maximum gradient r = 0.98, p less than 0.001; mean gradient r = 0.97, p less than 0.001). Mean Doppler-catheter differences were not significant, and no underestimation by Doppler reached or exceeded 5 mmHg. Correlations were also satisfactory in patients with aortic stenosis (maximum gradient r = 0.97, p less than 0.01; mean gradient r = 0.90, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Stenosis↗