Biomedical subjects

M Bonneau

Publications and source records attributed to M Bonneau.

At least 37 records · Page 2Linked to original sources

PubMed1998

Role of plasma and platelet von Willebrand factor in arterial thrombogenesis and hemostasis in the pig.

To evaluate the relative role of plasma and platelet von Willebrand factor (vWF) pools in hemostasis and arterial thrombogenesis, pigs with vW disease (vWD) were injected with vWF concentrate and/or grafted with bone marrow from a normal pig. Hemostasis was assessed by measurement of ear immersion bleeding time, factor VIII (FVIII) activity, and plasma and platelet vWF antigen levels. The thrombotic process was explored at 650 s(-1) and 1600 s(-1) in an ex vivo cylindrical perfusion chamber. Pigs with vWD exhibited a prolonged bleeding time (>30 minutes) compared with normal pigs (<5 minutes); in addition, they showed normal platelet adhesion and thrombus formation at 650 s(-1) but profoundly reduced platelet adhesion and thrombus formation at 1600 s(-1). Each experiment was performed before and 3 and 24 hours after injection of vWF concentrate. In our bleeding time study, only plasma vWF restoration induced a partial but delayed correction (24 hours postinjection), which was correlated with the highest measured level of FVIII activity. In the perfusion chamber model, restoration of plasma or platelet vWF pools resulted in similar partial correction of platelet adhesion and average thrombus size. In the perfused pigs, the maximum correction occurred 3 hours postinjection. Platelet deposition reached normal values after vWF concentrate was injected into a grafted pig. The present results suggest that when both plasma and platelet vWF levels are restored in vWD pigs, bleeding time and the thrombotic process are normalized according to different kinetics and with differing degrees of effectiveness.

Animals↗

PubMed1997

Developmental changes in lipogenic enzymes in muscle compared to liver and extramuscular adipose tissues in the rabbit (Oryctolagus cuniculus).

The developmental changes in the activities of acetyl-CoA-carboxylase, malic enzyme and glucose-6-phosphate dehydrogenase were compared in longissimus muscle, liver and adipose tissues in growing rabbits. Activities of lipogenic enzymes were low in muscle, as compared to the other tissues studied. The lipogenic activities in longissimus muscle increased with age. This increase was well correlated with the age-related increase in intramuscular lipid content, suggesting that intramuscular adipose tissue results from in situ lipid synthesis. During growth, each tissue displayed a specific developmental pattern for lipogenic enzyme activities. In liver and adipose tissues, the three lipogenic enzyme activities first increased and subsequently decreased, during the postweaning period. In the muscle, no such decrease was observed, suggesting that intramuscular adipose tissue develops later than the other tissues tested. Throughout postnatal period, the ratio of malic enzyme to glucose-6-phosphate dehydrogenase was reversed in muscle compared to other fat sites (5 vs 0.04). Further studies are necessary to determine the role of malic enzyme in rabbit intramuscular lipid metabolism.

Acetyl-CoA Carboxylase↗

PubMed1997

Effects of simultaneous gestation and lactation in rabbit does on muscular characteristics of the youngs.

The aim of the experiment was to determine the influence of concurrent gestation and lactation in rabbit does on the post-natal growth and muscular characteristics of the progeny. Myosin heavy chain (MHC) isoform proportion, myofibrillar protein content and size of the myofibres were determined on day 29 or day 70 in the semitendinosus muscle of young rabbits born from either simultaneously pregnant and lactating does (PL group) or from only pregnant does (P group). There were no significant differences in the weight of the young rabbits of the two groups throughout the post-natal period, despite a non-significant reduction of birth weight by 9% in the PL group. On day 29, the proportion of perinatal MHC was higher (5.8% vs 2.3%) and that of the type-II isoforms was lower (91.5% vs 95.0%) in the PL group than in the P group (P < 0.01). The simultaneous gestation and lactation affected the maturation of secondary fibres. On day 70, the proportion of the MHC isoforms was similar in the two groups. These results suggest that concurrent gestation and lactation delayed the myofibrillar maturation rate.

Animals↗

PubMed1997

Moderate food restriction affects skeletal muscle and liver growth hormone receptors differently in pigs.

The present study was conducted to determine the influence of food restriction on growth hormone receptor (GHR) in porcine skeletal muscle (longissimus dorsi and trapezius) and liver in relationship to plasma growth hormone binding protein (GHBP). At 76 d of age, pigs were allotted to one of three groups. In Group R100kg-196d, pigs were fed 70% of control food intake and slaughtered at 100 kg. Control pigs had free access to food and were slaughtered either at the same weight (Group C100kg-161d) or at the same age (Group C130kg-196d) as R100kg-196d pigs. Plasma insulin-like growth factor-I concentrations tended to be lower in food-restricted pigs than in control pigs at 40 kg (P < 0.1) and 70 kg (P < 0.05). At slaughter, there were no significant differences among the three groups. In liver, 125I-labeled bovine GH specific binding was higher (P < 0.05) in food-restricted pigs than in control pigs, and GHR mRNA level was higher (P < 0.05) in food-restricted pigs than in C100kg-161d pigs. In trapezius, 125I-labeled bovine GH specific binding was lower (P < 0.05) in food-restricted pigs than in C130kg-196d pigs, and the level of GHR mRNA was higher (P < 0.01) in food-restricted pigs than in control pigs. The levels of GHR in longissimus dorsi were not affected by food restriction. The level of plasma GHBP was lower (P < 0.05) in food-restricted pigs than in C130kg-196d pigs. These data indicate that nutritional status regulates GHR in a tissue-specific manner and that there is no simple relationship between plasma GHBP and hepatic GHR in pigs.

Animals↗

PubMed1997

Isolation and identification of Salmonella species from chelonians using combined selective media, serotyping and ribotyping.

Thirty-two faecal samples from various pet chelonians were bacteriologically examined using various combinations of selective media for Salmonella detection. Strains identified as Salmonella were clustered by rRNA gene restriction pattern (ribotyping) analysis prior to serological typing. The combination of selenite broth and Rambach or Salmonella-Shigella agars gave the maximum rate of Salmonella recovery. Of the 32 samples examined, 13 (40%), were positive for Salmonella. Five serovars were identified, Muenchen, Rubislaw, Newport, Ferruch and a non-motile O:4,5,12, with Salmonella Muenchen the most common. This result indicates that biochemical characterization combined with ribotyping prior to serotyping can contribute to Salmonella detection on a large scale.

Animals↗

PubMed1997

Effect of GH administration on GH and IGF-I receptors in porcine skeletal muscle and liver in relation to plasma GH-binding protein.

The present study was undertaken to determine the effect of GH administration on GH and IGF-I receptors in skeletal muscle compared with liver in growing pigs. Plasma IGF-I and GH-binding protein (GHBP) levels were also determined. Twelve Large White pigs (castrated males) were treated daily with 100 micrograms pituitary porcine GH (pGH) per kg body weight or vehicle for 41 days intramuscularly. Relative to controls, pGH administration increased plasma IGF-I concentrations by 3.3-fold. Administration of pGH had no effect on plasma GHBP levels. In liver, 125I-labelled bovine GH (bGH)-specific binding (P < 0.05) and GH receptor (GHR) mRNA levels (P < 0.05) were higher in pGH-treated than in control pigs. In longissimus dorsi (LD), 125I-labelled bGH specific binding did not differ significantly between the two groups while GHR mRNA levels (P < 0.05) were lower in pGH-treated than in control pigs. Administration of pGH had no effect on 125I-labelled bGH-specific binding and GHR mRNA levels in trapezius (TR). 125I-Labelled IGF-I-specific binding in liver was unaffected by pGH administration. Similarly, in liver, LD and TR, IGF-I receptor mRNA levels were not different between pGH-treated and control animals. It can be concluded that (1) GH binding and IGF-I receptor mRNA are not affected by GH in skeletal muscle, (2) GH influences GHR in a tissue-specific manner and (3) hepatic GHR and GHBP levels are not co-regulated.

Analysis of Variance↗

PubMed1996

Aortocaval fistulae: a percutaneous model and treatment with stent grafts in sheep.

BACKGROUND: Treatment of aortocaval fistulae (ACFs) by open surgery is known to be a high-risk procedure. In this experimental study, we developed a percutaneous model of ACF to test a new nonsurgical method of treatment of ACF using endovascular stent grafts. METHODS AND RESULTS: An ACF was created percutaneously in eight sheep. Via a combined venous and arterial femoral approach, angioplasty balloons were inserted to occlude the infrarenal aorta and inferior vena cava (IVC). The IVC was punctured through the lateral aortic wall with a transjugular liver biopsy needle. The fistulous tract was then dilated with an 8-mm angioplasty balloon, and the animal was heparinized. Two weeks later, a 10-mm Cragg-Endopro-Stent was inserted into the aorta at the level of the fistula via a percutaneous femoral approach. ACFs were successfully created in all animals, with rapid dye shunt through the fistula and a 20% increase in cardiac pulsations. Follow-up angiograms at 2 weeks showed a patent ACF, and stent implantation excluded the fistula in every case. Angiographic and pathological examinations up to 6 months demonstrated normal aortic patency and persistent exclusion of the fistulae. CONCLUSIONS: ACFs were effectively treated by endovascular grafting of the aorta. The animal model and the stenting procedures were both performed percutaneously.

Angioplasty, Balloon↗

PubMed1996

Platelet functions and haemostasis parameters in pigs: absence of side effects of a procedure of general anaesthesia.

Pigs are largely used as experimental animal models of thrombosis and for testing the anti thrombotic drug efficacy. Generally experiments are performed on pigs under general anaesthesia and observations can be affected by the anaesthetic drugs used. The effects of a general anaesthetic procedure were checked on pig haemostasis parameters; the pig was pre-anaesthetized with ketamine chloride, then intubated and ventilated with a mixture containing halothane, nitrous oxide and oxygen. Bleeding time, platelet aggregations, coagulation factors, coagulation inhibitors, fibrinolysis parameters and markers of activation of coagulation were determined on 30 Large White pigs before and under this anaesthesia procedure. Compared to human coagulation, pig is characterized by very high levels of factor V, VIII, IX, XI, XII activities, same levels of factor II, fibrinogen, antithrombin III (ATIII), low levels of protein C activities. Thrombin-antithrombin complex (TAT) and tissue plasminogen activator antigen (tPA) values were dispersed. With the reagents used, protein S, prothrombin fragment 1 + 2 (F1 + 2), D Dimers (D-D), plasminogen activator inhibitor (PAi) levels could not be determined. No difference was observed between results obtained before and under anaesthesia, particularly to increase of bleeding time, no modification of platelet aggregations and no activation of coagulation. This anaesthetic procedure does not induce any modification of pig haemostasis and can be used, without side effects, for experimental thrombosis studies in pigs.

Anesthesia, General↗

PubMed1996

Developmental changes in insulin-like growth factor-I (IGF-I) receptor levels and plasma IGF-I concentrations in large white and Meishan pigs.

The developmental pattern of insulin-like growth factor-I receptor (IGF-IR) and plasma IGF-I concentrations were examined in longissimus dorsi (LD), trapezius (TR), and liver from the last third of gestation up to 1 year of age in male Large White (LW) and Meishan (MS) pigs. Plasma IGF-I concentrations increased between 75 days of gestation and 180 days of age with a 100-fold increase and decreased thereafter. At 180 and 365 days of age, plasma IGF-I concentrations were higher in LW than in MS pigs. 125I-IGF-I specific binding was detected in liver and skeletal muscle (not determined in fetal TR) from 75 days of gestation until the adult stage in both breeds. Affinity cross-linking experiments followed by electrophoresis under reducing conditions revealed the presence of one band with an apparent molecular weight of 140 kDa in fetal liver and LD. In displacement experiments, data indicated that IGF-I bound specifically to IGF-IR in both prenatal and postnatal tissues. Specific binding increased between 75 and 90 days of gestation in both liver and LD. It remained elevated until 103-113 days of gestation and tended to be higher in MS than in LW fetal liver. After birth, it decreased to remain stable thereafter. The developmental pattern of IGF-IR is concluded to be similar in liver and skeletal muscle of LW and MS pigs. The few differences observed between LW and MS pigs cannot account for their different growth performances. The high binding in fetus suggests that IGF-IR may play an important role in fetal growth and development.

Aging↗

PubMed1996

Myosin isoform transitions in four rabbit muscles during postnatal growth.

Four rabbit muscles (i.e. semimembranosus proprius, psoas major, biceps femoris and longissimus lumborum), differing in their fibre type composition in the adult, were investigated during postnatal development. Muscle samples were taken at 1, 7, 14, 21, 28, 35, 49 and 77 days of age. Complementary techniques were used to characterize myosin heavy chain (MHC) isoform transitions, i.e. SDS-PAGE, immunocytochemistry and conventional histochemistry. Good accordance was found between electrophoretic and immunocytochemical techniques. Our results show that rabbit muscles were phenotypically immature at birth. At 1 day of age, perinatal isoform represented 70-90% of the total isoform content of the muscles. Two generations of myofibres could be observed on the basis of their morphology and reaction to specific antibodies. In all muscles, primary fibres expressed slow MHC. In contrast, secondary generation of fibres never expressed slow MHC in future fast muscles, while half of them expressed slow MHC in the future slow-twitch muscle, the semimembranosus proprius. During the postnatal period, all muscles displayed a transition from embryonic to perinatal MHC isoforms, followed by a transition from perinatal to adult MHC isoforms. These transitions occured mainly during the first postnatal month. The embryonic isoform was no longer expressed after 14 days, except in longissimus where it disappeared after 28 days. On the contrary, large differences were found in the timing of disappearance of the perinatal isoform between the four muscles. The perinatal isoform disappeared between 28 and 35 days in semimembranosus proprius and 35 and 49 days in psoas and biceps femoris. Interestingly, the perinatal isoform was still present in 6% of the fibres in longissimus at 77 days, the commercial slaughter age, denoting a great delay in the maturation. Fate of each generation of fibres differed between muscles.

Aging↗

PubMed1996

Effect of a growth hormone infusion on plasma insulin-like growth factor-I in Meishan and large white pigs.

Plasma growth hormone (GH) and insulin-like growth factor-I (IGF-I) levels were determined in Large White (LW) and Meishan (MS) female pigs at 80 and 185 days of age before and after an infusion of porcine GH. Plasma GH concentration declined with age and was similar in both breeds. Plasma IGF-I concentration did not differ between MS and LW pigs at 80 days of age. It increased with age in LW pigs whereas it remained almost unchanged in MS pigs. GH infusion led to an increase in plasma GH concentration and elicited a rapid and persistent rise in plasma IGF-I levels in both breeds. IGF-I response to GH was lower in LW than in MS pigs at 80 days, whereas the reverse was observed at 185 days of age. It increased with age in LW while it declined in MS pigs. The present results suggest the development of a GH resistance in MS pigs. This is likely associated with sexual maturity. Whether such GH resistance would also be observed in postpubertal LW female pigs remains to be investigated.

Animals↗

PubMed1996

Which experimental model to choose to study arterial thrombosis and evaluate potentially useful therapeutics?

The use of experimental models of arterial thrombosis both in vivo and ex vivo in animals and ex vivo in humans is an obligatory step for the understanding of mechanisms involved in thrombogenesis as well as in the evaluation of anti-thrombotic therapeutics. Arterial thrombogenesis is a complex phenomenon which involves multiple systems, mechanisms and parameters. Therefore studies of thrombogenesis from a pathological as well as a therapeutic point are necessary for understanding this problem in its entirety. For these reasons, it is necessary to use models as representative as possible of the human pathological condition. Besides these theoretical requirements, practical needs have also to be fulfilled (accessibility of the models, adaptation to the type of the technique to different animal model and/or of the size of the animal to the amount of molecule available, cost...) which necessarily lead to some compromises. In this review we have tried to underline the criteria for the choice, characteristics, advantages and disadvantages of the major models commonly accepted and used, in such a form that the reader who may not be an expert in the field would be led either to a choice of a particular model for a specific purpose or to appreciate a paper or a report based on an experimental model of arterial thrombosis. In vitro models of arterial thrombosis are so far removed from reality and due to their nature can generate so much artifacts that we have omitted their discussion from this paper.

Animals↗

PubMed1996

Ontogeny of GH receptor and GH-binding protein in the pig.

The present study was undertaken to examine the developmental pattern of GH receptor (GHR) and GHR gene expression in skeletal muscle (longissimus dorsi and trapezius (TR)) and liver from the last third of gestation until 1 year of age in male Large White (LW) and Meishan (MS) pigs. Plasma GH-binding protein (GHBP) levels were also measured. 125I-Labelled bovine GH (bGH) specific binding (not determined in foetal TR) and GHR mRNA were detected in skeletal muscle from 75 days of gestation until the adult stage with no clear age-related changes. By contrast, 125I-labelled bGH specific binding and GHR mRNA were undetectable or barely detectable in foetal liver. After birth, 125I-labelled bGH specific binding (P < 0.001) and GHR mRNA in liver increased with age. The level of bGH binding to liver membranes was higher in MS than in LW pigs at 1, 45, 80 and 120 days of age and did not differ between breeds at the other ages. Specific binding of 125I-labelled human GH (hGH) to plasma GHBP was easily detected as early as 75 days of gestation and increased with age (P < 0.001). The level of hGH binding to plasma GHBP was higher in MS than in LW pigs at 1, 80 and 120 days of age. It can be concluded that (1) the developmental expression of the GHR is tissue-specific, (2) the presence of GHBP in foetuses despite the absence of GHR in liver suggests that other tissues such as skeletal muscle could contribute to the generation of GHBP and (3) the presence of GHR in skeletal muscle as early as 75 days of gestation suggests that GH may play a role in foetal muscle growth.

Animals↗

PubMed1996

Factors regulating the concentrations of 16-androstene steroids in submaxillary salivary glands of pigs.

The measurement of 16-androstene steroids in submaxillary salivary glands is a potentially good way to estimate boar taint. The objective of this work was to identify factors regulating the concentrations of these steroids in salivary glands. Large White x Pietrain male pigs were divided into four treatments: T-1, intact untreated (n = 18); T-2, intact treated with porcine somatotropin (pST, n = 18); T-3, intact immunized against LHRH (n = 20); and T-4, castrated untreated (n = 19). The pigs were slaughtered at 105 mg of live weight. The mean concentrations of the compounds measured after slaughter for T-1 were as follows: 16-androstene steroid binding protein (pheromaxein) in salivary glands, 2.08 +/- .19 micrograms/g; 16-androstene steroids in salivary glands, 43.3 +/- 2.9 micrograms/g; androstenone in fat, .67 +/- .07 micrograms/g. In all other treatments, the concentrations were reduced (P = .001); T-2 and T-3 had intermediate and T-4 had the least concentrations of the measured compounds. The reduction of 16-androstenes in salivary glands was less than androstenone in fat, probably due to pheromaxein. The overall correlation between androstenone and 16-androstenes was r = .602 (P < .001) and for T-1 was r = .613 (P < .001). The overall correlation between pheromaxein and 16-androstenes was r = .777 (P < .001) and r = .928 (P < .001) for T-1. Only in T-3 was the estimation of the relationship between androstenone and 16-androstenes improved by measuring pheromaxein. These results indicate that pheromaxein is more closely related to the concentration of 16-androstene steroids in salivary glands than in fat. Synthesis of pheromaxein is dependent on mature, functional testes. We conclude that boar taint can be estimated by measuring the concentrations of 16-androstene steroids in salivary glands.

Androstenes↗

PubMed1996

An experimental model for testing von Willebrand factor function: successful SLA-matched crossed bone marrow transplantations between normal and von Willebrand pigs.

To assess the relative in vivo roles of von Willebrand factor (vWF) of different origins, we performed crossed bone marrow transplantations (BMTs) among normal pigs and pigs with the von Willebrand disease(vWF). The two groups were fully compatible immunologically according to typing by swine leukocyte antigen (SLA). After total-body irradiation (8-10 Gy), all pigs received 0.5X10(9) to 10(10)/kg mononuclear bone marrow cells without any immunosuppression. The nadir of aplasia occurred between days 5 and 7 after irradiation (white blood cell [WBC] count 0.6X10(9)/L, platelet [Plt] count 76X10(9)/L. Three weeks after the graft, WBC and Plt counts had returned to normal levels. Animals were followed for at lease 50 days, during which no bone marrow rejection occurred; no evidence of graft-vs-host disease (GVHD) was observed. Each BMT was confirmed by karyotype analysis. In the six homozygous pigs with vWD grafted with normal marrow, platelet vWF antigen (vWFAg) and platelet vWF activity rose from <3 to 450 U/dl with a normal multimeric pattern; plasma vF increases slightly. No correction of bleeding time was observed. In the five normal pigs grafted with bone marrow form pigs with vWD, platelet vWFAg and platelet vWF activity decreased from >100 U/dl to undetectable levels; bleeding time and plasma vWFAg remained unchanged. A derivative of normal porcine plasma, a concentrate containing factor VIII and vWF, was infused into a homozygous vWD pig before and after BMT from a normal pig. Co correction of bleeding time was obtained, even though plasma nd platelet vWFAg levels were normal. W concluded that crossed BMT among SLA-identical pigs is a feasible model of studying the synthesis and the roles of vWF in hemostasis and thrombosis.

Animals↗

PubMed1996

[What are the criteria for choosing a model for evaluating arterial antithrombotic therapy?].

The use of models of experimental arterial thrombosis both in vivo and ex vivo in animals and ex vivo in humans is an obligatory step to the understanding of mechanisms involved in thrombogenesis as well as in the evaluation of anti-thrombotic therapeutics. Arterial thrombogenesis is a complex phenomenon which involves multiple systems, mechanisms and parameters. Therefore studies of thrombogenesis from a pathological as well as a therapeutic point are necessary for understanding this problem in its entirety. For these reasons, it is necessary to use models as representative as possible of the human pathological condition. Besides these theoretical requirements, practical needs have also to be fulfilled (accessibility of the models, adaptation to the type of the technique to different animal model and/or of the size of the animal to the amount of molecule available, cost ...) which necessary lead to some promises. In this review we have tried to underline the criteria for the choice, characteristics, advantages and disadvantages of the major models commonly accepted and used, in such a form that the reader who may not be an expert in the field would be led either to choose a particular model for a specific purpose or to appreciate a paper or a report based on an experimental model of arterial thrombosis. In vitro models of arterial thrombosis are so far removed from reality and due to their nature can generate so much artifacts thus we have omitted their discussion from this paper.

Animals↗

PubMed1995

Characterization of a new gene family developing pleiotropic phenotypes upon mutation in Saccharomyces cerevisiae.

The aim of this paper is to gather and complete data about four members of a new gene family. Mutation in SUR4 gene was originally selected as a suppressor of defects caused by mutations in RVS161 or RVS167 genes. Cloning and sequencing of the SUR4 gene were performed. The deduced protein contains six putative transmembrane domains. Sequence comparison revealed that two yeast genes, FEN1 and JO343, shared significant similarities with SUR4. Mutants for SUR4 and FEN1 have the same pleiotropic phenotype, including bud localization defects, resistance to an immunosuppressor and resistance to ergosterol biosynthesis inhibitors. The double inactivation of SUR4 and FEN1 genes is lethal. These data and other aspects implicating SUR4 in glucose metabolism, suggest an involvement of these genes in the dynamics of cortical actin cytoskeleton in response to nutrient availability. Moreover, the existence of a fourth homologous gene in C. elegans extends the family to pluricellular organisms.

Amino Acid Sequence↗

PubMed1995

Function of von Willebrand factor after crossed bone marrow transplantation between normal and von Willebrand disease pigs: effect on arterial thrombosis in chimeras.

von Willebrand factor (vWF) is essential for the induction of occlusive thrombosis in stenosed and injured pig arteries and for normal hemostasis. To separate the relative contribution of plasma and platelet vWF to arterial thrombosis, we produced chimeric normal and von Willebrand disease pigs by crossed bone marrow transplantation; von Willebrand disease (vWD) pigs were engrafted with normal pig bone marrow and normal pigs were engrafted with vWD bone marrow. Thrombosis developed in the chimeric normal pigs that showed normal levels of plasma vWF and an absence of platelet vWF; but no thrombosis occurred in the chimeric vWD pigs that demonstrated normal platelet vWF and an absence of plasma vWF. The ear bleeding times of the chimeric pigs were partially corrected by endogenous plasma vWF but not by platelet vWF. Our animal model demonstrated that vWF in the plasma compartment is essential for the development of arterial thrombosis and that it also contributes to the maintenance of bleeding time and hemostasis.

Animals↗