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J P Renard

Publications and source records attributed to J P Renard.

At least 19 recordsLinked to original sources
PubMed2006

Assessing the quality of products from cloned cattle: an integrative approach.

Scientific expertise was developed during a 3-year study to evaluate a large number of bovine female clones (n=37; from 4 to 36 months of age) and their products through a multidisciplinary approach and compare them to non-cloned breed, age and sex-matched contemporary control animals (n=38) maintained under the same conditions at the same experimental farm of INRA. In clone and control groups, most parameters measured for health and development of the animals as well as evaluation of milk and meat products were within the normal range for the breed. The strict comparison between cloned animals and controls allowed us to detect slight significant differences between the two groups. Cloned heifers reached puberty significantly later (+62 days) and at higher body weight (+56kg) than controls. There were slight differences in antigen-specific induced proliferation of lymphocytes after vaccination with ovalbumin before 10 months of age, but responses were normal responses in older animals. There were differences in the fatty acid (FA) composition of milk and muscle arising from two families of clones, suggesting a possible deviation in lipid metabolism as assessed by higher Delta-9 desaturase activity indices in both milk and muscle from clones compared to controls. Nutritional evaluation of milk and meat using the rat model did not reveal any difference between products derived from clones versus controls.

Animals↗
PubMed2006

Large offspring or large placenta syndrome? Morphometric analysis of late gestation bovine placentomes from somatic nuclear transfer pregnancies complicated by hydrallantois.

Somatic nuclear transfer (NT) in cattle is often complicated by fetal oversize (i.e., large offspring syndrome), hydrallantois, and placentomegaly in late gestation. The aims of this work were to obtain data on the placentome structure in NT-recipient cows with hydrallantois (NTH) and to relate these with fetal and placental weights to better understand the abnormalities observed in NTH pregnancies during the third trimester. Pregnant cows were slaughtered between Gestation Days 180 and 280. The fetuses were weighed, and the placentomes were numbered and weighed. Placentomes were examined by histologic and stereological techniques. Macroscopic data showed that placental overgrowth preceded fetal overgrowth, and the ratio of the fetal to the total placentome weight in the NTH group was lower than that in controls after Gestation Day 220. This suggests that placental overgrowth is due to placental default rather than due to fetal overgrowth, as shown also by stereological analysis showing primary deregulation of the growth of cotyledonary tissues. Observed alterations, such as thinning of the maternal epithelium within placentomes and increased trophoblastic surface, could be secondary adaptations. Thus, placental growth deregulations would be due to modifications of the expression of placental factors. Various examples of placental deficiency were observed, suggesting that some fetal abnormalities observed in NTH calves, such as enlarged heart, enlarged umbilical cord, and abdominal ascites, are consequences of placental dysfunction. Therefore, the condition described by the term "large offspring syndrome" might better be described by "large placenta syndrome," because this syndrome affects an average of 50% of late-gestation NT pregnancies. No conclusion can be drawn from this work on apparently normal pregnancies.

Allantois↗
PubMed2005

SSH adequacy to preimplantation mammalian development: scarce specific transcripts cloning despite irregular normalisation.

BACKGROUND: SSH has emerged as a widely used technology to identify genes that are differentially regulated between two biological situations. Because it includes a normalisation step, it is used for preference to clone low abundance differentially expressed transcripts. It does not require previous sequence knowledge and may start from PCR amplified cDNAs. It is thus particularly well suited to biological situations where specific genes are expressed and tiny amounts of RNA are available. This is the case during early mammalian embryo development. In this field, few differentially expressed genes have been characterized from SSH libraries, but an overall assessment of the quality of SSH libraries is still required. Because we are interested in the more systematic establishment of SSH libraries from early embryos, we have developed a simple and reliable strategy based on reporter transcript follow-up to check SSH library quality and repeatability when starting with small amounts of RNA. RESULTS: Four independent subtracted libraries were constructed. They aimed to analyze key events in the preimplantation development of rabbit and bovine embryos. The performance of the SSH procedure was assessed through the large-scale screening of thousands of clones from each library for exogenous reporter transcripts mimicking either tester specific or tester/driver common transcripts. Our results show that abundant transcripts escape normalisation which is only efficient for rare and moderately abundant transcripts. Sequencing 1600 clones from one of the libraries confirmed and extended our results to endogenous transcripts and demonstrated that some very abundant transcripts common to tester and driver escaped subtraction. Nonetheless, the four libraries were greatly enriched in clones encoding for very rare (0.0005% of mRNAs) tester-specific transcripts. CONCLUSION: The close agreement between our hybridization and sequencing results shows that the addition and follow-up of exogenous reporter transcripts provides an easy and reliable means to check SSH performance. Despite some cases of irregular normalisation and subtraction failure, we have shown that SSH repeatedly enriches the libraries in very rare, tester-specific transcripts, and can thus be considered as a powerful tool to investigate situations where small amounts of biological material are available, such as during early mammalian development.

Animals↗
PubMed2005

[Confinement and consumption of cloned and transgenic animals].

Reproduction by cloning can eliminate some of the problems inherent to sexual reproduction, but it creates others. The genetic heritage of nucleus donor cells and the genetic status of clones are not precisely known. Furthermore, reprogramming of the genome of nucleus donor cells by the ovocyte cytoplasm is often incomplete. Animals obtained through cloning are thus essentially genetically identical to their genitors, but they are often epigenetically modified, with unpredictable effects. Transgenesis results in most cases from the addition to a genome of one or more known genes. The direct and indirect effects of transgenesis cannot all be predicted. Specific confinement measures make it possible to raise animals in high-security conditions, preventing their dissemination in the human food chain, in animal feed or in the environment. The toxicity, allergenicity and infectiousness of cloned ortransgenic animals can be evaluated by means of tests.

Animals↗
PubMed2004

Magnetic filaments in resistive manganites.

The magnetic phase separation in single crystals of the Pr0.67Ca0.33MnO3 manganites is studied using polarized small angle neutron scattering. The measured spectra give a fractal dimension consistent with a configuration in ferromagnetic filaments of nanometric diameter. We argue here that localized charge carriers hop in a random walk fashion mediating a ferromagnetic "hopping exchange" which coexists with superexchange to create the filamentary phase separation. The arguments for this physical picture are validated by Monte Carlo simulations, where magnetism and transport are treated in a self-consistent manner.

Journal Article↗
PubMed2003

Preliminary results on variability in oocyte recovery and developmental competence in cattle derived from embryonic cloning: work in progress.

To investigate female gamete developmental competence and variability in cloned cattle, we performed ovum pick-up and in vitro fertilization in four sets of cloned heifers (n = 10, two sets of triplets and two sets of twins), and four groups of non-genetically related control animals (n = 13). A total of 304 OPU were performed and 1798 oocytes were recovered. Mean oocyte production per female per OPU (+/-S.D.) was similar for clone or control animals (5.7+/-2.9 versus 6.1+/-4.5, respectively), however, in two sets of clones variance for the number of oocytes recovered differed significantly (7.1 versus 23.9 and 7.3 versus 26.7, respectively P<0.001) between clone groups and their respective controls, cloned animals being more homogenous. After in vitro maturation, fertilization with semen from the same bull, and culture, the proportion of oocytes from cloned animals that developed into blastocysts was 35.0+/-29.2% and was not significantly different from controls (29.4+/-30.9). The CV for oocyte recovery, and blastocyst rates was lower in all groups of cloned animals than in controls. Nevertheless, within each set of clones, CV values indicated some degree of variability between animals, thus confirming that cloned cattle are not the exact phenotypic copy of each other. Despite the large number of oocytes analyzed, results should be interpreted with caution due to the limited number of cloned animals.

Animals↗
PubMed2003

Identification of differentially expressed mRNAs in bovine preimplantation embryos.

We have characterised the changes in preimplantation embryos that occur in the mRNA population during the transition from maternal to zygotic control of embryogenesis. We connected the mRNA differential display method and RT-PCR based method that allows amplification of the whole population of messengers. In the early stages of development we have further characterised the level of individual mRNAs with the help of semiquantitative RT-PCR used with specific primers. This report concerns four of 12 cDNA fragments that appeared to be differentially expressed between the 4- and late 8-cell stages. A transcript corresponding to fragment no. 1/12 appears to be analogous to the maternal mRNA since it is abundant in 1-, 2-, 4- and 8-cell embryos and rapidly decreases in the later stages. A similar pattern of expression was revealed in the transcript corresponding to fragment no. 8/9. A transcript corresponding to fragment no. 20/8 is newly synthesised from the embryonic genome at the late 8-cell stage and its amount rapidly increases during the following stages. This messenger shows a 91.7% identity with mRNA for human S3A ribosomal protein and 92.2% identity with mRNA for Felis domesticus S3A ribosomal protein. A transcript corresponding to fragment no. 8/19 is stage-specific, being newly synthesised from an embryonic genome at the late 8-cell stage and decreasing in the later stages. This messenger shows 86.6% identity with a mouse mRNA for proline-rich protein and 91.6% identity with human mRNA for KIAA-0058 gene. A complex of these molecular markers represents a suitable tool for answering questions concerning the molecular control of major gene activation during bovine embryogenesis.

Animals↗
PubMed2003

Consequences of transvaginal follicular puncture on well-being in cows.

The purpose of this study was to evaluate the impact of repeated follicular puncture used in the ovum pick-up technique on the welfare of cows. The evaluation relies on the physiological measurement of stress, milk production criteria, immune status, and the histological examination of ovaries. Two groups of five Holstein cows were submitted to epidural anaesthesia and genital palpation with insertion of an intravaginal ultrasound probe for transvaginal puncture (the puncture was not performed in the control group). Animals were manipulated twice a week for 8 weeks (16 manipulation sessions). The blood cortisol concentrations increased after each session; however, the concentrations were the same in both the control and the punctured groups. Two adrenocorticotrophic hormone challenge tests, performed before the first session and after the last session, showed an unchanged adrenal sensitivity through repeated puncture sessions. The transvaginal puncture did not affect milk production, or blood and milk somatic cell counts. Ovariectomies were performed on another group of four Holstein cows at various intervals (0 to 30 days) after five similar puncture sessions. Histological examination of the ovaries 4 days after puncture revealed blood-filled follicles and haemorrhagic foci in ovarian stroma, but the examination 30 days after the last puncture session demonstrated very limited, if any, fibrosis. On the basis of the criteria chosen for this study, repeated transvaginal follicular puncture on its own does not impact adversely on the welfare of cows.

Animals↗
PubMed2003

Evidence of oocyte donor cow effect over oocyte production and embryo development in vitro.

There have been few studies on a possible maternal influence on in vitro embryo production in cows. The objective of this study was to evaluate the maternal influence on oocyte production and in vitro blastocyst formation rate using repeated ovum pick-up and in vitro fertilization. Six contemporary cows raised on the same farm and with varied genetic origins were submitted to 42 weeks of ovum pick-up organized into four series. Collected oocytes were fertilized in vitro with spermatozoa from a different bull for each series. In total, 1933 oocytes were recovered from 3936 follicles with a recovery rate of 57.2% and a mean oocyte collection of 4.6+/-0.2 (mean+/-SEM) per animal per session. Animals were ranked according to their oocyte production. The best oocyte donor was the same female in all four series. No relationship was identified between oocyte production and blastocyst production rate (r=-0.08). The mean blastocyst rate was 28.8% with significant variation among animals. The best and the worst blastocyst producers were always the same animals independent of the semen used. The results of the present study support the hypothesis that in cattle, the oocyte donor influences the production of blastocysts. Furthermore, they demonstrate that oocyte and embryo production are independent factors. Further studies are necessary to identify the maternal or oocyte factors responsible for such differences.

Animals↗
PubMed2002

Up-regulation of glucose metabolism during male pronucleus formation determines the early onset of the s phase in bovine zygotes.

After in vitro fertilization with spermatozoa from bulls with high in vitro fertility, a beneficial paternal effect is manifested during the G1 phase of the first cell cycle. This benefit determines an earlier onset of the first S phase, and then a successful morula-blastocyst transition 7 days later. We hypothesized that the origin of the paternal effect could be a shift of the metabolism of the fertilized oocyte, because in mice, sperm decondensation is responsible for a dramatic increase in glucose metabolism. In this study we investigated the interaction between both pronuclei and compared glycolysis and pentose phosphate pathway (PPP) activities in bovine oocytes fertilized with spermatozoa from bulls of high or low fertility. Here we demonstrate that male pronucleus formation is necessary for the onset of the S phase in the female pronucleus, and that the component promoting an early S phase in both pronuclei is metabolic and linked to an up-regulation of the PPP during the male pronucleus formation. This long-lasting paternal effect is more evidence of the important role of epigenetic control during early embryo development.

6-Aminonicotinamide↗
PubMed2002

Nuclear transfer technologies: between successes and doubts.

Cloning of mammals by nuclear transfer can lead to the birth of healthy adult animals but more often compromises the development of the reconstructed embryos. A high incidence of fetal and postnatal losses has been observed in several species, revealing the existence of long-lasting effects induced by the nuclear transfer procedures. Remodeling of donor chromatin by the recipient cytoplasm after nuclear transfer is frequently associated with the deregulation of specific genes, and recent observations point to the potential importance of time-dependent DNA methylation events in the occurrence of these alterations. Screening strategies to design nuclear transfer procedures that would mimic the epigenetic remodeling occurring in normal embryos are being designed, and improvement in the efficiency of procedures could imply a pre-conditioning of donor cells. Early mammalian development appears to be rather tolerant to epigenetic abnormalities, raising the possibility that even a fully functional reprogrammed genome may have been subjected to some epigenetic alterations. Bringing nuclear transfer to routine practice requires greater knowledge and understanding of the basic biological processes underlying epigenetic controls of nuclear activities. An important issue at present is to limit the production of those aberrant phenotypes that may result in significant insult to the nature and welfare of animals.

Animals↗
PubMed2002

[Paraneoplastic dermatopolymyositis with mild glomerular lesion nephropathy associated with non-Hodgkin's lymphoma].

INTRODUCTION: Dermatopolymyositis is an inflammatory disorder of an unknown origin. Twenty to thirty percent cases of this disease are associated with a cancer. Glomerular lesions in dermatopolymyositis are rare. EXEGESIS: We describe the case of a patient who presented a dermatopolymyositis together with a glomerulopathy and then a non Hodgkin's lymphoma. A treatment by corticoid and secondary intravenous immune globulins because of corticoid-resistance of the dermatopolymyositis and oesophagus injury led to a significant improvement of the cutaneous signs and of the muscular weakness. This favourable evolution was also determined by the chemotherapy for lymphoma. Nine months after the diagnosis of dermatopolymyositis remission for dermatopolymyositis and lymphoma is obtained. We also noticed a regression of the glomerular signs. CONCLUSION: A diagnosis of dermatopolymyositis must lead to a meticulous search for an associated cancer. Data from literature indicate that a cancer is usually discovered within the first year of dermatopolymyositis' diagnosis but it can appear until five years after this diagnosis. The most frequent organs concerned by cancer are ovary and the digestive tract. A meta-analysis showed an incidence-standardised rate for lymphoma important in patients suffering from dermatopolymyositis. The treatment of the cancer can improve the evolution of the dermatopolymyositis. However corticoid must be the first treatment for dermatopolymyositis. In case of corticoid-resistant dermatopolymyositis or dermatopolymyositis involving oesophagus treatment by intravenous immune globulins is justified. At last when a glomerular nephropathy is discovered in such a situation, paraneoplasic glomerulopathy, renal lymphomatous infiltration or another associated immune disease must be called to mind.

Aged↗
PubMed2002

Novel approaches and hurdles to somatic cloning in cattle.

The overall efficiency of somatic cloning in cattle is still low. Many factors are necessary for successful birth of live offspring. Among them, the source of donor cells reveals the importance of the donor genotype but also the influence of the cell line itself. The cell cycle stage has been intensively investigated, and recent results indicate that, in cattle, the G0 stage of the donor nuclei is not a prerequisite for reprogramming, as highly proliferating cultured fibroblasts also result in live offspring after nuclear transfer. A technical approach using direct microinjection of fibroblast nuclei, instead of fusion of the whole cell, has proved to result in high in vitro development rates in cattle. However, full-term development of somatic cloned embryos is still limited by long-lasting effects and a high incidence of losses at periimplantation time (as well as in late gestation and around calving).

Animals↗
PubMed2002

Frequency and occurrence of late-gestation losses from cattle cloned embryos.

Nuclear transfer from somatic cells still has limited efficiency in terms of live calves born due to high fetal loss after transfer. In this study, we addressed the type of donor cells used for cloning in in vivo development. We used a combination of repeated ultrasonography and maternal pregnancy serum protein (PSP60) assays to monitor the evolution of pregnancy after somatic cloning in order to detect the occurrence of late-gestation losses and their frequency, compared with embryo cloning or in vitro fertilization (IVF). Incidence of loss between Day 90 of gestation and calving was 43.7% for adult somatic clones and 33.3% for fetal somatic clones, compared with 4.3% after embryo cloning and 0% in the control IVF group. Using PSP60 levels in maternal blood as a criterion for placental function, we observed that after somatic cloning, recipients that lost their pregnancy before Day 100 showed significantly higher PSP60 levels by Day 50 than those that maintained pregnancy (7.77 +/- 3.3 ng/ml vs. 2.45 +/- 0.27 ng/ml for normal pregnancies, P < 0.05). At later stages of gestation, between 4 mo and calving, mean PSP60 concentrations were significantly increased in pathologic pregnancy after somatic cloning compared with other groups (P < 0.05 by Day 150, P < 0.001 by Day 180, and P < 0.01 by Day 210). In those situations, and confirmed by ultrasonographic measurements, recipients developed severe hydroallantois together with larger placentome size. Our findings suggest that assessing placental development with PSP60 and ultrasonography will lead to better care of recipient animals in bovine somatic cloning.

Animals↗
PubMed2002

Nucleolar changes in bovine nucleotransferred embryos.

This study focused on nucleolar changes in bovine embryos reconstructed from enucleated mature oocytes fused with blastomeres of morulae or with cultured, serum unstarved bovine fetal skin fibroblasts (embryonic vs. somatic cloning). The nucleotransferred (NT) embryos were collected and fixed at time intervals of 1-2 h (early 1-cell stage), 10-15 h (late 1-cell stage), 22-24 h (2-cell stage), 37-38 h (4-cell stage), 40-41 h (early 8-cell stage), 47-48 h (late 8-cell stage), and 55 h (16-cell stage) after fusion. Immunocytochemistry by light and electron microscopy was used for structure-function characterization of nucleolar components. Antibodies against RNA, protein B23, protein C23, and fibrillarin were applied. In addition, DNA was localized by the terminal deoxynucleotidyl transferase (TdT) technique, and the functional organization of chromatin was determined with the nick-translation immunogold approach. The results show that fully reticulated (active) nucleoli observed in donor cells immediately before fusion as well as in the early 1-cell stage after fusion were progressively transformed into nucleolar bodies displaying decreasing numbers of vacuoles from the 2- to 4-cell stage in both types of reconstructed embryos. At the late 8-cell stage, morphological signs of resuming nucleolar activity were detected. Numerous new small vacuoles appeared, and chromatin blocks reassociated with the nucleolar body. During this period, nick-translation technique revealed numerous active DNA sites in the periphery of chromatin blocks associated with the nucleolar body. Fully reticulated nucleoli were again observed as early as the 16-cell stage of embryonic cloned embryos. In comparison, the embryos obtained by fetal cloning displayed a lower tendency to develop, mainly during the first cell cycle and during the period of presumed reactivation. Correlatively, the changes in nucleolar morphology (desegregation and rebuilding) were at least delayed in many somatic NT embryos in comparison with the embryonic NT group. It is concluded that complete reprogramming of rRNA gene expression is part of the general nuclear reprogramming necessary for development after NT.

Animals↗
PubMed2002

Clinical, hormonal, and hematologic characteristics of bovine calves derived from nuclei from somatic cells.

Although healthy animals are born after nuclear transfer with somatic cells nuclei, the success of this procedure is generally poor (2%-10%) with high perinatal losses. Apparently normal surviving animals may have undiagnosed pathologies that could develop later in life. The gross pathology of 16 abnormal bovine fetuses produced by nuclear transfer (NT) and the clinical, endocrinologic (insulin-like growth factors I and II [IGF-I and IGF-II], IGF binding proteins, post-ACTH stimulation cortisol, leptin, glucose, and insulin levels), and biochemical characteristics of a group of 21 apparently normal cloned calves were compared with those of in vitro-produced (IVP) controls and controls resulting from artificial insemination. Oocytes used for NT or IVP were matured in vitro. NT to enucleated oocytes was performed using cultured adult or fetal skin cells. After culture, Day 7, grade 1-2 embryos were transferred (one per recipient). All placentas and fetuses from clones undergoing an abnormal pregnancy showed some degree of edema due to hydrops. Mean placentome number was lower and mean placentome weight was higher in clones than in controls (69.9 +/- 9.2 placentomes with a mean weight of 144.3 +/- 21.4 g in clones vs. 99 and 137 placentomes with a mean individual weight of 34.8 and 32.4 g in two IVP controls). Erythrocyte mean cell volume was higher at birth (P < 0.01), and body temperature and plasma leptin concentrations were higher and T4 levels were lower during the first 50 days and the first week (P < 0.05), respectively, in clones. Plasma IGF-II concentrations were higher at birth and lower at Day 15 in clones (P < 0.05). Therefore, apparently healthy cloned calves cannot be considered as physiologically normal animals until at least 50 days of age.

Adrenocorticotropic Hormone↗
PubMed2002

[Corneal burns and matrix metalloproteinases (MMP-2 and -9): the effects of human amniotic membrane transplantation].

PURPOSE: Human amniotic membranes have recently been used in ophthalmology to restore deleted ocular surface after burns. Matrix metalloproteinases-2 and -9 have been implicated in the development of neovascularization. In this study, MMP-2 and MMP-9 expression was analyzed by in situ zymography on rabbit corneal chemical burns with and without human amniotic membrane graft. METHOD: Corneal neovascularization was induced in 10 Fauve de Bourgogne rabbits by means of a heptanol chemical burn on controlled deep keratotomy using a Chiron ALK-E corneal shaper. Half of rabbits received acute amniotic membrane transplantation 30mn after chemical burn; the remaining five rabbits received medical treatment. In situ zymography is a recent nondestructive technique which preserved the fine morphological details of the cornea and showed the active enzyme location in different corneal layers. The MMP-2 and -9 substrate was gelatin, which was detected by fluorescent microscopy. RESULTS: There was an overexpression of MMP-2 and -9 in corneal burns versus control corneas. Expression of MMP-2 and -9 was low in corneal burn without amniotic membrane graft. Following amniotic membrane transplantation, MMP-2 and -9 were strongly expressed and clinical neovascularization and inflammation decreased. Active enzymes were located in epithelium layers in the uncovered group. In the covered group, the active enzymes were located in the anterior and posterior stromal layers. CONCLUSION: The results support a role for MMP-2 and MMP-9 in corneal burn neovascularization. Amniotic membrane transplantation can play a protective role by up-regulation of their biological expression.

Amnion↗