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Biomedical subjects

M Bonneau

Publications and source records attributed to M Bonneau.

At least 55 records · Page 3Linked to original sources
PubMed1995

Absence of incorporation of plasma von Willebrand factor into porcine platelet alpha-granules.

In order to study the relationship between plasma and platelet von Willebrand factor (vWF), we used an experimental model of crossed bone marrow transplantation (BMT) between SLA immunocompatible normal and homozygous von Willebrand (vWD) pigs. A normal pig received bone marrow from a vWD pig and a second pig with vWD was engrafted with marrow from a normal pig. Each recipient, after total irradiation of 10 Grays, received by a central catheter 10(10) monocellular bone marrow cells without immunosuppression. The animals were followed for 50 d and no graft rejection or graft-versus-host disease was observed. After aplasia occurring 3 weeks after BMT, white blood cells and platelets returned to normal. Before transplantation, in the vWD pig, vWFAg and vWF activity were not detected in plasma and in platelet and megakaryocyte alpha-granules. After transplantation with normal marrow, platelet vWFAg and platelet vWF activity wer normal and high molecular weight multimers and numerous tubular structures were present in alpha-granules. Before transplantation, the normal pig had normal plasma and platelet vWFAg-vWF activity, normal multimeric pattern, and the platelet and megakaryocyte alpha-granules displayed many tubular structures, eccentrically located in one of their poles, coinciding with immunogold staining vWFAg. After transplantation with homozygous vWD marrow, platelet and megakaryocyte alpha-granules lacked tubular structures. Alpha-granule immunogold staining for vWF was consistently negative, although plasma vWF was at a normal level. In conclusion, this study shows that, unlike other plasma proteins such as fibrinogen. vWF endocytosis does not occur from plasma to the platelet alpha-granules. Platelet and megakaryocyte vWF solely originates from megakaryocyte endogenous synthesis and is independent of plasma vWF.

Animals↗
PubMed1995

Incorporation of fibronectin-impregnated vascular prostheses in the pig. Microscope study.

An interface near the endothelial extracellular matrix is necessary to augment and maintain endothelial cell attachment. The use of plasma lectins constitutes one of the present lines of research designed to improve this interface. We studied the incorporation of 2 series of arterial prostheses with a diameter of 4 mm and a mean length of 9 cm. They were implanted in the carotid arteries of adult Europig minipigs. Prostheses were of two types: polytetrafluoro-ethylene (PTFE) and knitted Dacron. Two series of 12 pigs each were used. One was explanted at 3 months and the other at six. Each pig was grafted with one prosthesis impregnated with the plasma components of diluted Fibrogel and one non-impregnated prosthesis which served as control. The explanted prostheses and adjacent parts of the carotid were prepared for light or scanning electron microscopy. Proximal, median and distal segments were cut and embedded in resin. Collagen distribution was revealed by Milligan's trichrome stain, and fibrin distribution by Picro-Mallory staining. Macroscopic examination showed discrete periprosthetic adhesion for impregnated prostheses and complete adhesion for non-impregnated prostheses. Scanning electron microscopy revealed a median endothelial cell coating on impregnated grafts whereas the only endothelial cells on non-impregnated grafts, were perianastomotic. On impregnated grafts, Milligan's trichrome staining revealed an even collagen distribution. The walls of non-impregnated grafts exhibited capillary cell infiltrations with breaches in the outer structures. In impregnated prostheses, the absence of such breaches enabled us to postulate that their incorporation was better than that of the non-impregnated grafts. The minipig model was hard to handle because of the aggressiveness engendered by restricted feeding designed to limit weight increases. In general, however, we may justifiably conclude that in this model, the use of plasma lectins improved prosthetic incorporation.

Animals↗
PubMed1994

Ontogeny of interferon alpha secreting cells in the porcine fetal hematopoietic organs.

We examined the ontogeny of IFN-alpha Secreting Cells (IFN-alpha SC) in different hematopoietic organs and blood of porcine fetuses at different stages of gestation. Cells were induced to produce IFN-alpha by incubation with the coronavirus TGEV and IFN-alpha SC were detected by ELISPOT. A striking finding was that IFN-alpha SC could be detected in the fetal liver as early as at 26 days of gestation, i.e., during the first quarter of gestation, a period at which T-cell markers could not be detected by flow cytometry. In addition, IFN-alpha SC could be detected in the cord blood, the spleen and the bone marrow of fetuses at later stages of gestation. These data indicate that IFN-alpha SC appear very early during the ontogeny of the immune system, long before the development of the specific immune system, and may therefore represent an early antiviral defence mechanism. IFN-alpha SC were found to be associated with hematopoietic organs, which argues for their hematopoietic lineage.

Animals↗
PubMed1994

The effects of immunization against luteinizing hormone-releasing hormone on performance, sexual development, and levels of boar taint-related compounds in intact male pigs.

The effect of a newly developed anti-LH-RH vaccine on the performance, sexual development, and incidence of boar taint-related compounds was investigated in young intact male pigs. At 29 kg BW, 40 crossbred intact males and 20 castrates were allocated to three groups. Castrates and half of the intact males were untreated. The remaining intact males were immunized against LH-RH at 29 kg and again at 89 kg BW. All pigs were slaughtered at 105 kg BW. Compared with control intact males, feed efficiency in castrates was decreased by 10%, muscle content was reduced by 5%, and carcass fat content was increased by 26%. Growth performance and carcass traits did not differ significantly between immunized and control intact males. Genital tract weight, measured at slaughter, was decreased (P < or = .002) by immunization. Plasma testosterone concentrations were not significantly affected at 89 kg BW, whereas they were sevenfold lower (P < .001) in immunized than in control intact males at 105 kg BW. Fat androsterone levels, measured at slaughter, were substantially reduced (P < .001) from .66 +/- .07 microgram/g in control to .21 +/- .01 microgram/g in immunized intact males. Rates of testicular steroid biosynthesis, measured in vitro, were decreased by immunocastration. Fat skatole levels were very low and did not differ significantly between the three groups. The present results demonstrate that anti-LHRH immunization was effective in reducing the level of androstenone, a boar taint-related compound, although having a limited effect on the performance of the animals.

Adipose Tissue↗
PubMed1994

Aprotinin could promote arterial thrombosis in pigs: a prospective randomized, blind study.

Haemostatic properties of aprotinin could be associated with an increased risk of thrombosis. A randomized, blinded study was conducted to consider the potential thrombogenicity of aprotinin, using the Folts' model on femoral arteries in 12 pigs. The flow variations were measured by a pulsed Doppler in anaesthetised animals. Ear immersion bleeding time was performed. During the first part of the study, a stenosis was performed successively on both femoral arteries, each for a period of 30 min, without prior injury, to assess the integrity of the vessel, and to check that the arteries did not develop cyclic flow reductions (CFR), permanent cessation of flow (PCF) or partial thrombosis, when a stenosis is applied. Then the clamp was released and a bolus of placebo (saline), or aprotinin (4 millions KIU, followed by a continuous infusion of 1 million KIU.h-1), was administered. At the end of the bolus, the second part of the study began. Stenosis was applied to the arteries. If CRF, PCF, or partial thrombosis were observed without prior injury then the infused drug (aprotinin or saline) was considered a prothrombotic drug, and the opposite artery was studied. For each animal, right and left femoral artery segments were fixed and studied (morphologic study). Eighteen arteries were studied. In the aprotinin group, 6 arteries out of 8 developed an unexpected thrombosis, as compared with only 2 out of 10 arteries in the control group (p = 0.02). The morphologic study confirmed the occurrence of thrombosis in 4 out of 7 arteries in the aprotinin group, as compared with only 1 out of 9 in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Evidence for linkage between K88ab, K88ac intestinal receptors to Escherichia coli and transferrin loci in pigs.

Segregation at the loci coding for the K88ab and K88ac small intestinal receptors to E. coli adhesins (K88abR, K88acR) and at the transferrin (TF) locus was studied in 38 pig families including 273 piglets. The TF locus showed a segregation deviation towards the B variant while each of the K88 receptors behaved as a single autosomal dominant gene. Recombinants between K88abR and K88acR provide evidence that they are under the control of two different loci. Thirty-two triple backcross families were selected to test linkage and estimate recombination rates (theta). Our results demonstrate that the two K88 receptor loci are closely linked (theta = 0.02) with a maximum lod score value (Zm) of 46.0. In addition, they are linked to the TF locus, theta = 0.14, Zm = 19.6 for the K88abR locus and theta = 0.16, Zm = 17.9 for the K88acR locus. The estimated recombination rates, smaller in males than in females, are consistent with the order TF-K88abR-K88acR. This linkage thus localizes the K88 loci, as the TF locus, on chromosome 13.

Adhesins, Escherichia coli↗
PubMed1993

Growth hormone response to GRF and insulin-induced hypoglycemia in Yorkshire and Meishan pigs.

Plasma glucose and porcine growth hormone (GH) responses to insulin and/or growth hormone-releasing factor (GRF) challenges were determined in Yorkshire (Y) and Meishan (MS) castrated male pigs at 140 days of age. The decline in glucose levels observed during the first 30 min after insulin injection was similar between the two breeds. In Y pigs, GH concentrations increased sharply after insulin injection. The GH response to insulin was much smaller in MS than in Y pigs (101 +/- 82 vs. 1,077 +/- 124 ng.min.ml-1, P < 0.001 after 0.30 U/kg insulin). The GH response to GRF (10 micrograms/kg) did not differ significantly between the two breeds. The GH response was larger after combined insulin (0.20 U/kg) plus GRF than after GRF alone in Y pigs (1,512 +/- 229 vs. 463 +/- 401 ng.min.ml-1, P < 0.05), whereas it did not differ in MS pigs (714 +/- 164 vs. 507 +/- 127 ng.min.ml-1, P > 0.10). The present data demonstrate that the GH response to insulin is dramatically altered in MS pigs. A possible explanation to this result is that somatostatin tone would not be depressed by insulin-induced hypoglycemia in MS pigs.

Animals↗
PubMed1993

Metabolic and endocrine changes associated with undernutrition in the peripubertal gilt.

The effect of feed restriction on circulating metabolites and metabolic and gonadotropic hormones was determined in Large White gilts. From 25 kg BW and 80 d of age, control gilts (CTRL, n = 10) were fed close to ad libitum intake, whereas restricted-fed gilts (REST, n = 10) were offered approximately 50% of the CTRL diet. Estrus was detected with a mature boar. Serial blood samples were collected at approximately 160 and 210 d of age from 0800 to 2000. A meal was supplied at 0900, and an i.v. injection of GnRH (80 ng/kg BW) was given at 1600. The gilts were slaughtered at 220 d of age. No REST and four CTRL gilts exhibited their first estrus between the two series of blood samplings. Feed intake, daily gain, and fat content of the carcass were reduced by 50% in REST gilts (P < .001). Preprandial concentrations of free fatty acids were significantly lower in CTRL gilts at 210 d of age than at 160 d and than in REST gilts at both ages. Within the CTRL group, concentrations were lower (P < .05) at both ages in gilts pubertal before 210 d than in others. After the meal, plasma insulin and urea increased in all gilts, whereas glucose increased and free fatty acids decreased in all except the 210-d CTRL gilts. The afternoon concentration of cortisol was slightly higher (P = .09) in REST than in CTRL gilts. The number of pulses and mean and interpulse concentrations of growth hormone did not show any clear variation with feed level and age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Comparative arterial antithrombotic activity of clopidogrel and acetyl salicylic acid in the pig.

We investigated the comparative antithrombotic properties of clopidogrel, an analogue of ticlopidine, and aspirin, using the Folts' model on femoral arteries in 22 pigs. On each animal, clopidogrel or aspirin were used to treat the thrombotic process on the left femoral artery and to prevent this process on the right femoral artery. Sequentially: an injury and stenosis were carried out on the left femoral artery; the thrombotic process was monitored with a Doppler during a 30-min observation period for cyclic flow reductions or permanent cessation of flow; after the first cyclic flow reduction occurred, clopidogrel (5 mg kg-1) or aspirin (2.5, 5, 100 mg kg-1) were injected intravenously; if cyclic flow reductions were abolished, epinephrine (0.4 micrograms kg-1 min-1) was injected to try to restore cyclic flow reductions and/or permanent cessation of flow; then injury and stenosis were applied on the right femoral artery. Before and after injection of clopidogrel or aspirin, ear immersion bleeding times and ex-vivo platelet aggregation were performed. Clopidogrel (n = 7) abolished cyclic flow reductions were efficiently prevented, even for two injuries. Basal bleeding time (5 min 28) was lengthened (> 15 min, 30 min after clopidogrel and remained prolonged even after 24 h). ADP-induced platelet aggregation was inhibited (more than 78%). Comparatively, aspirin had a moderate and no dose-dependent effect. Aspirin 2.5 mg kg-1 (n = 6) abolished cyclic flow reductions in 2 animals, CFR reoccurred spontaneously in one animal and epinephrine restored it in a second animal.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Performance, plasma hormones, histochemical and biochemical muscle traits, and meat quality of pigs administered exogenous somatotropin between 30 or 60 kilograms and 100 kilograms body weight.

Forty-five Large White barrows were injected daily i.m. with either excipient from 30 to 100 kg BW (CTRL), excipient from 30 to 60 and porcine somatotropin (pST; 100 micrograms/kg BW) from 60 to 100 kg BW (pST-60), or pST (100 micrograms/kg BW) from 30 to 100 kg BW (pST-30). Somatotropin accelerated overall growth rate (+4 and +9% for pST-60 and pST-30, respectively), increased longissimus (+10.3 and +14.7%) and semitendinosus (+17 and +13%) muscle weights, and decreased backfat (-49 and -58%) and leaf fat (-49 and -53%) weights. The administration of pST resulted in a similar increase in muscle fiber size for all fiber types in both longissimus (LM) and semispinalis (SS) muscles (+21%). Somatotropin had otherwise little effect on muscle fiber types and biochemical traits of LM, whereas dramatic changes were observed in SS. The relative area occupied by Type IIB fibers was increased (+22 and +29%) and that of Type I fibers was decreased (-10 and -15%). In pST-30 animals, myosin ATPase activity (+15%) and native myosin fast isoform proportion (+10%) were augmented, and energy metabolism was more glycolytic (lactate dehydrogenase: +25%) and less oxidative (citrate synthase: -13%; beta-hydroxyacyl-CoA dehydrogenase: -21%). Compared to CTRL animals, administration of pST increased muscle water concentration (LM: +.8 and +1.1%: SS: +3.3 and +3.3%) and decreased intramuscular fat (LM: -29 and -27%; SS: -39 and -50%). The pH measured 45 min and 24 h postmortem, glycogen content, reflectance, and index of light diffusion were mostly not affected by pST treatment. In conclusion, pST had a very favorable effect on growth performance without any important effect on meat quality traits except for the reduction in intramuscular lipid content. The results indicated that the effects of pST on muscular histochemical and biochemical characteristics were different in LM and SS muscles.

Adipose Tissue↗
PubMed1992

Effects of administration of growth hormone-releasing factor to sows during late gestation on growth hormone secretion, reproductive traits, and performance of progeny from birth to 100 kilograms live weight.

The effects of growth hormone-releasing factor (GHRF) injections to sows during late gestation were investigated in two experiments. In the first one, four treatments were applied to eight catheterized sows according to two 4 x 4 Latin squares: oral administration of 2 mg of pyridostigmine, a cholinesterase inhibitor, per kilogram of BW (PYR group); i.m. injection of 50 micrograms of GHRF/kg BW (GHRF group); a combination of the pyridostigmine and GHRF treatments (PYR+GHRF); or i.m. injection of glucose (control). Pyridostigmine slightly increased the plasma concentration of growth hormone (GH). Growth hormone responses to GHRF and PYR+GHRF treatments were similar, with significantly elevated GH concentrations from 5 to 240 min after GHRF injection. In the second experiment, 36 sows were allocated to two treatments at 102 d of gestation. Until farrowing, they were injected twice daily with 50 micrograms of GHRF/kg BW (GHRF group) or isotonic glucose (control). The DM, N, fat, and energy content of 24 pigs per group was determined at weaning at 22 d. Six pigs per litter had ad libitum access to feed until slaughter at 100 kg BW and their carcasses were evaluated. Treatment with GHRF increased pregnancy duration (114.8 vs 113.6 d, P less than .05), weight of pigs at 13 d (3.69 vs 3.54 kg, P less than .05) and at weaning (5.74 vs 5.48 kg, P less than .05), and improved pig survival (86 vs 71%, P less than .05). Lipid (on a DM basis) and energy contents of the pigs slaughtered at weaning were significantly higher in the GHRF group than in the control group (14.4 vs 12.5% and 2,178 vs 2,029 kcal/kg, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Characterization of a thrombopathy (type delta storage pool disease) affecting a pig colony.

An autosomal recessive thrombopathy in pigs is described and characterized functionally, morphologically and biochemically. The affected pigs have a severe bleeding diathesis and a markedly prolonged bleeding time but normal plasma and platelet von Willebrand factor (vWF) levels. Electron micrographs and fluorescence microscopy with mepacrine reveal reduced numbers of dense granules in platelets as compared to normals. This thrombopathy is a pure delta storage pool disease (SPD), as evidenced: a) biochemically by platelet serotonin content and metabolism and by comparative ATP/ADP content and secretion; b) functionally by reduced aggregability to low concentrations of convulxin and collagen but normal aggregability to other agents and normal synthesis of thromboxane B2. The affection was first discovered in a colony of von Willebrand's disease (vWD) pigs, but is biologically and genetically distinct. It is possible to completely separate the SPD from the vWD, although originally animals could be affected by both vWD and SPD. Normal plasma and platelet alpha granule content of vWF are found in diseased animals. An intermediate disorder is also detected in animals not severely affected, which may represent the heterozygous state.

Acetylserotonin O-Methyltransferase↗
PubMed1992

Heterosynapsis in two fertile but hypoprolific boars carriers of reciprocal translocations.

The authors report here two new cases of reciprocal translocations in two fertile and hypoprolific boars. Silver stained synaptonemal complexes in surface-spread pachytene nuclei from a boar heterozygous for a reciprocal translocation, and from another one carrying two different reciprocal translocations, were analyzed by electron microscopy. In such heterozygotes, cross-shaped quadrivalent configurations are expected to form in order to allow homologous pairing. In the same boar, the lengths of the fully synapsed arms of the quadrivalent varies from one quadrivalent to the other and heterosynapsis was obvious. Heterosynapsis was also observed with asymmetrical pairing of the non-homologous partners of the quadrivalent. This heterosynapsis is assumed to be a mechanism preventing spermatocyte loss, but inducing a secondary segregational type of impairment of fertility due to foetal wastage leading to reduced prolificacy.

Animals↗
PubMed1992

A method for cytogenetic analysis of boar spermatozoa using hamster oocytes.

In this paper, the authors detail a method for displaying boar spermatozoa chromosomes using heterospecific zona-free hamster oocyte penetration technique. Semen samples from two Large-White boars having a normal spermogram were studied. The first one had a normal karyotype (38,XY), the second carried a reciprocal translocation rcp(3;7)(p1,3;q2,1). After in vitro fertilization by capacitated sperm, culture and cytogenetic analysis of hamster eggs we obtained metaphase spreads of spermatozoa chromosomes. The ratio of X- and Y-bearing spermatozoa was 49.2% and 50.8%, respectively.

Animals↗
PubMed1991

Age-related changes in plasma porcine growth hormone (GH) profiles and insulin-like growth factor-I (IGF-I) concentrations in Large White and Meishan pigs.

Plasma GH profiles and IGF-I concentrations were determined in Large White intact male (LW-M), female (LW-F) and castrated male (LW-C) and in Meishan intact male (MS-M) pigs between 10 and 140 d of age. Mean GH levels slightly increased between 10 and 45 d of age in LW pigs, in connection with an alteration in the temporal distribution of GH peaks, whereas neither interpulse GH level nor maximum GH level were affected. Mean GH levels decreased after 45 d of age, in connection with a decline in maximum and interpulse GH levels. IGF-I concentrations were low between 10 and 45 d of age and increased thereafter. GH secretory profiles did not differ significantly between LW-M and LW-F at either age. Castration had no effect at 45 d of age whereas LW-C exhibited lower mean, maximum and interpulse GH levels and smaller sum of GH pulse areas and widths than LW-M or LW-F at 140 d of age. IGF-I was lower in LW-C or LW-F than in LW-M at 140 d of age. The pattern of age-related changes in GH and IGF-I was similar in MS and LW pigs. However, interpulse GH level was higher and sum of GH pulse widths was smaller in MS-M than in LW-M, whatever the age. The results indicate that: i), GH and IGF-I secretions were similar in Meishan, and Large White pigs; ii), in both breeds, GH secretion declined after 45 d of age, due to decreased maximum and interpulse GH levels; iii), sex and/or castration effects on GH and IGF-I secretion were observed after 45 d of age only.

Aging↗
PubMed1991

Biosynthesis of 16-androstene steroids and testosterone by porcine testis tissue in vitro: effect of age and relationships with fat 5 alpha-androstenone levels in vivo.

The relationships between testicular 16-androstene and testosterone formation in young pigs and levels of 5 alpha-androstenone in fat exhibited at older ages were investigated. Testis tissue samples were taken from Large White male pigs at 75, 100 and 125 days of age (8 pigs per age group) and incubated with a mixture of [3H]progesterone and [14C]pregnenolone. 5 alpha-androstenone levels in fat were measured in all 24 pigs at 125, 145 and 170 days of age. Less androstadienone, more 3 alpha-androstenol and 11-fold more 3 beta-androstenol + androstadienol were synthesized from pregnenolone than from progesterone. 5 alpha-androstenone synthesis increased significantly between 100 and 125 days, whereas that of androstadienone declined between 75 and 100 days of age. Litter had a significant effect on all 16-androstene rates of formation. Fat 5 alpha-androstenone levels were positively correlated with 5 alpha-androstenone formation from both precursors. They were correlated with 3 beta-androstenol + androstadienol (positively) and testosterone (negatively) rates of synthesis from progesterone. It is concluded that in vitro measurements of 5 alpha-androstenone formation by testis tissue could be used as an early predictor of fat 5 alpha-androstenone levels exhibited at older ages.

Adipose Tissue↗
PubMed1991

Effect of human growth hormone-releasing factor on bone and mineral metabolism in growing pigs.

Little information is available on the effects of growth hormone (GH) and growth hormone-releasing factor (GRF and GHRH) treatment on bone metabolism in pigs. Thus, tibial bending moments and ash contents were studied in 12, 6-wk-old pigs weighing 13 +/- .2 kg. Six pigs (GRF group) were injected s.c. twice daily with 75 micrograms GRF (hGRF [1-29] NH2)/kg BW for 52 d and six remained untreated (control group, C). Average daily gain was slightly (5%; P less than .10) increased in treated pigs. At slaughter, plasma measurements related to calcium homeostasis, such as concentrations of Ca, inorganic P, and vitamin D metabolites (25-OH and 1,25-(OH)2 vitamin D3), were not changed by GRF injection. At slaughter, plasma GH levels were 3.3 times greater in treated (11.3 +/- 3 ng/ml) than in untreated pigs (3.4 +/- .5 ng/ml, P less than .02), whereas those of insulin-like growth factor I were increased by approximately 38%. No difference was observed between the two groups at slaughter in tibial weight, density, bending moment, ash relative to bone volume (29 +/- 1 vs 30 +/- 2 g/100 cm3, GRF vs C), total ash content, or ash relative to dry matter in cortical or medullary bone. Our GRF treatment did not affect bone and mineral metabolism in young, growing pigs.

Animals↗