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Biomedical subjects

A Vallet

Publications and source records attributed to A Vallet.

17 recordsLinked to original sources
PubMed2006

Recombinant protein Bd37 protected gerbils against heterologous challenges with isolates of Babesia divergens polymorphic for the bd37 gene.

The Bd37gene encoding for a glycosyl-phosphatidyl-inositol anchored protein of Babesia divergens displays genetic polymorphisms among isolates. Five major polymorphic groups (clades) were shown by PCR-RFLP among different B. divergens isolates. Each group has been characterized according to a reference Bd37 gene (Rouen87, W8843, Y5, 6303E and 1705B). Recombinant (GST fusion) protein (Bd37r) expressed from the Bd37 gene, was used as antigen in a saponin-based formulation and was able to protect gerbils, after 2 injections at low dose vaccine concentration (1 mug per dose), against a virulent challenge with the B. divergens Rouen87 isolate. In spite of polymorphism of Bd37 gene, Bd37r induced complete immunoprotection against challenges with each of the 5 reference isolate groups defined by PCR-RFLP.

Amino Acid Sequence↗
PubMed2005

[Heat stroke and fulminans hepatitis: is MARS system relevant?].

Exertional heat stroke (EHS) is a life-threatening condition caused by an extreme elevation in core body temperature. Acute liver failure has been reported during EHS justifying liver transplantation in some cases. The Molecular Adsorbent Recirculating System (MARS) could be indicated in such situations. We report a case of a 58-year old patient who suffered acute liver failure occurring after EHS. The patient was referred for liver transplantation and benefited of MARS therapy. After three sessions of MARS, liver function improved progressively and the transplantation was not necessary. The patient completely recovered.

Bilirubin↗
PubMed2005

Changes to hepatocyte ploidy and binuclearity profiles during human chronic viral hepatitis.

BACKGROUND AND AIMS: The importance of the hepatocyte ploidisation pattern to the control of cell proliferation and differentiation has been well established. However, there are no data that have characterised hepatocyte ploidy at various stages of chronic liver inflammation and fibrosis in vivo. METHODS: We therefore investigated hepatocyte ploidy/binuclearity patterns in 57 patients with chronic hepatitis, using a recently developed methodology which allows simultaneous hepatocyte ploidy and binuclearity analyses on the same liver section. RESULTS: The percentage of mononuclear diploid hepatocytes was significantly reduced in patients with high hepatitis activity and marked fibrosis (low activity: 75.1 (18.8)% v high activity: 61.8 (21.6)%, p=0.0111, and low fibrosis: 77.3 (13.8)% v high fibrosis: 57.4 (23.3)%, p=0.0002). Accordingly, the percentage of mononuclear polyploid hepatocytes increased in patients with high hepatitis activity and marked fibrosis (low activity: 11.9 (15.5)% v high activity: 22.2 (20.1)%, p=0.0166, and low fibrosis: 9.4 (10.7)% v high fibrosis: 26.4 (21.6)%, p=0.0001). In addition, the fraction of binuclear hepatocytes was significantly higher in patients with hepatitis B virus (HBV) than in those with hepatitis C virus (HCV) infections (HBV: 18.2 (7.6)% v HCV: 12.0 (4.8)%; p=0.0020). Under multivariate analysis, HBV infection was an independent factor accounting for the larger binuclear hepatocyte fraction (p=0.0294). CONCLUSION: Our results revealed an increase in the polyploid hepatocyte fraction which correlates with the severity of chronic hepatitis; moreover, we demonstrated that HBV and HCV related chronic hepatitis exhibited distinctive hepatocyte ploidy patterns, thus allowing the suggestion that these two viral infections may modulate liver ploidy through different mechanisms.

Adult↗
PubMed2004

Association between sequence polymorphism in an epitope of Babesia divergens Bd37 exoantigen and protection induced by passive transfer.

In Europe, Babesia divergens is the major agent responsible for babesiosis in cattle and can occasionally infect splenectomised humans. Recently, we reported the characterisation of a 37 kDa exoantigen (Bd37) anchored in the merozoite membrane of B. divergens by a glycosylphosphatidyl-inositol. After phospholipase hydrolyse of the glycosylphosphatidyl-inositol anchor, the Bd37 antigen could be isolated in the plasma of the infected host and from the in vitro culture supernatants. Immunisation of mice with a gel-filtration protective fraction of B. divergens exoantigens, produced a monoclonal antibody (MAb), called F4.2F8-INT, directed against Bd37. In the present study, we report data on passive protection using MAb F4.2F8-INT. This MAb was able to completely protect against virulent challenges with B. divergens isolates Rouen 1987 (Rouen87) and Weybridge 8843 (W8843) but had no protective effect against another French isolate from Massif Central (6303E). Physical characterisation of the epitope recognised by F4.2F8-INT allowed us to explain the differences observed between these isolates by western blotting and passive protection. These results suggest that the antigen carrying this epitope could be used as a target in the development of a recombinant vaccine against B. divergens babesiosis.

Amino Acid Sequence↗
PubMed2002

Babesia divergens: cloning and biochemical characterization of Bd37.

The immunoprotective potential of Babesia divergens antigens released in supernatants of in vitro cultures of the parasite is generally known. Among a number of parasite molecules, a 37 kDa protein has been found in the supernatants of Babesia divergens cultures. In this report the cloning and biochemical characterization of this protein, called Bd37, are described. In addition, the processing of the protein was studied in vitro. Results suggest that Bd37 is encoded by a single copy gene. Bd37 appears to be a merozoite-associated molecule attached to the surface by a glycosylphosphatidylinositol moiety containing a palmitate residue attached to the inositol ring. In addition, it is demonstrated that both extremities of the protein are linked by a disulphide bond. Results further indicate that a soluble, hydrophilic form of Bd37 can be released from the merozoite surface by GPI-specific phospholipase D. The potential role the Bd37 protein and the GPI anchor are discussed.

Amino Acid Sequence↗
PubMed1993

Pontine myelinolysis following liver transplantation: a report of two cases.

Two cases of central pontine myelinolysis (CPM) following orthotopic liver transplantation (OLT) are reported. Several months after the onset of this neurological syndrome, the two patients are still alive but with severe neurological sequelae. Some patients undergoing emergency OLT present a high risk of CPM because of pre-existing malnutrition, encephalopathy, and hepatic insufficiency. All of these are associated with an inevitable abrupt rise in sodium serum concentration due to intraoperative compensation of blood losses with high-sodium content blood products. Whenever the renal capacity to excrete sodium is impaired by the surgical procedure, continuous intraoperative venovenous hemofiltration is recommended.

Adult↗
PubMed1991

[Use of homologous erythrocyte concentrates. Analysis of economical factors].

The factors involved in reducing consumption of bank packed red cells (PRC) were studied over three one year periods (1983, 1987 and 1989) in a Department of Vascular and General Surgery. The effects of autologous blood salvage (started in 1987), associated with the management of homologous blood by a branch of the blood bank inside the operating theater suite were assessed. In 1989, intentional normovolaemic haemodilution became virtually systematic, on top of the intraoperative blood salvage, for all patients due to undergo surgery with a risk of severe blood loss. The number of surgical procedures carried out during those three years did not vary. However, in the same time, the annual consumption of homologous PRC decreased by an overall 56% (36.7% between 1983 and 1987, and 29.8% between 1987 and 1989). This decrease was mostly due to a fall in prescription in the operating theaters, and not in the wards. In the same time, albumin consumption increased sixfold. Such transfusional policies can only be carried out if there is good cooperation between the blood bank and the prescribers of blood products.

Blood Banks↗
PubMed1987

[Hemodynamic changes caused by laparotomy during aorto-iliac surgery].

A haemodynamic study was carried out on 53 patients undergoing elective surgery of the abdominal aorta in order to assess the haemodynamic changes consequent to abdominal manipulations prior to aortic clamping. Surgery was carried out under general anaesthesia and ventilation was controlled. The following parameters were monitored: mean arterial pressure (Pa), cardiac index (CI), systolic index (SI), systemic vascular resistances (Rsa), pulmonary vascular resistances (Rpa), heart rate (fC). Cutaneous circulation was monitored using a photoplethysmographic transducer. The following haemodynamic pattern was seen as the peritoneal cavity was opened and traction on the mesentery was applied: CI +40.7%; fC +28.61%; SI +9.85%; Rsa -39.16%; Rpa -28.43%; Pa -15.7%. The recording of the facial cutaneous photoplethysmographic wave showed an increase of 50%. In some extreme cases, a state of cardiovascular collapse with marked cutaneous erythema strongly resembling anaphylactic shock ensued. The physiopathology of these cardiovascular reactions is unclear, but the haemodynamic pattern as well as the cutaneous vasodilation suggest a stimulation of both vagal and sympathetic nervous systems and the release of vasoactive substances into the general circulation.

Adult↗
PubMed1987

Treatment of deep venous thrombosis with a very low molecular weight heparin fragment (CY 222).

Thirty patients presenting with phlebographically confirmed deep venous thrombosis were treated with a very low molecular weight heparin fragment (CY 222) in an open and prospective phase-2 trial. A uniform dosage of 750 IC anti-factor Xa units/kg/day was administered subcutaneously for 10 days or more to patients whose thromboses were categorized as postsurgical (17 cases) or medical (13 cases). The clinical symptoms of venous thrombosis diminished in 93% of the patients overall. The extent of vascular clearing was assessed by an original scoring system which compared the pre- and posttreatment phlebographies. The effect of treatment was globally rated 'very good' (more than 75% lysis) in 37% of the patients, 'good' (about 50% lysis) in 40% and 'poor' (0-25% lysis) in 17%; the phlebographic thrombosis worsened in 6.6%. Little change occurred in laboratory tests exploring thrombolysis, but a strong anti-factor Xa activity was detected.

Adolescent↗
PubMed1986

[Peroperative autotransfusion].

Between April 1976 and December 1984, 297 patients underwent major elective and emergency surgery using intraoperative autotransfusion (Bentley ATS unit). An amount of 732 l of blood was reinfused, representing 61% of the total intraoperative blood transfusion. Thanks to this method, an average 2.46 l of blood per patient was spared, with a range of 0.9 to 6 l according to the type of surgery (elective or emergency). Twelve accidents are reported, including four bradycardias (less than 45 b X min-1), two air emboli and six haemorrhages due to an excess of anticoagulation. These complications were related either to poor technique (too great a transfusion output) or insufficient blood anticoagulation control. Simplicity of use and high transfusion output of the device adapted to the blood loss are the advantages of intraoperative autotransfusion.

Adult↗
PubMed1985

[Influence of rearing conditions on the frequency of diarrhea in newborn calves and the efficacy of oral treatment].

A survey was carried out in 181 holdings of various production types to measure the influence of calf housing conditions and feeding of cows during late pregnancy on the frequency of calf diarrhea and an oral treatment efficiency. A second objective was to compare the efficiency of the different oral rehydratants used. The frequency of diarrhea was 51%. Slightly more than half the cases occurred during the first week of life. The dam's unadequate feeding increased morbidity (53% versus 47% with adequate feeding). We were unable to measure the efficiency of good housing conditions, because only five holdings fitted the quality criteria which had been initially specified. In the other holdings, the cohabitation was found to be less harmful than separation in bad conditions: too many calves together, too small an area per animal, draughts or deficient air removal. Therapy efficiency was not significantly higher when appropriate feeding was given than with unadequate feeding. Treatment efficiency by an oral rehydratant only was lower with calves which were housed with their dam's than when they were outdoors. Three rehydratants, Electydral ND, Biodiet ND, Ionidiar ND had similar results that were significantly higher than those of the others. With the sodium acetate-based formula, Electydral ND, 30% of the calves recovered when it was given alone for 36 hours, 96% recovered when it was given for 72 hours, combined with oral antibiotic therapy for 36 hours.

Animal Husbandry↗
PubMedDate not supplied

[Hemodynamic and gasometric modifications during the anesthesia recovery period in patients undergoing ventilation after surgery of the abdominal aorta].

This study was carried out on 12 patients (mean age 61) in order to assess the oxygen consumption (VO2) in the post-operative stage of an elective surgical procedure (replacement of the abdominal aorta). Anesthesia was a combination of thiopentone, pancuronium bromide and high doses of droperidol and fentanyl. Patients were kept intubated and ventilated in the post-operative period. VO2 and other related metabolic parameters as well as hemodynamic parameters were measured every 45 minutes over a period of 5 hours. A VO2 increase (127%) related to the increase in body temperature was noted. Mean VO2 for all patients during the whole period was 170 +/- 13 ml.min-1.m-2 (range: 51-411 ml.min-1.m-2). Mean value of maximal VO2 was 240 +/- 21 ml.min-1.m-2 (range: 1471-411 ml.min-1.m-2). Large dose of droperidol are shown to limit VO2 increase. In patients with shivering, the maximal value of VO2 was found during shivering. The amount of droperidol administered during anesthesia was greater in patients without shivering. VO2 increase was due to a rise in tissular O2 extraction. Cardiac index was insufficiently increased (+ 9.4%) and a certain extent of myocardial inadaptability was suspected in relation with: high blood pressure, hypovolaemia and/or myocardial effect of anesthesia agents.

Anesthesia Recovery Period↗