The Experts below are selected from a list of 1140 Experts worldwide ranked by ideXlab platform
Antoine Blancher - One of the best experts on this subject based on the ideXlab platform.
-
Impact of MHC class II polymorphism on blood counts of CD4+ T lymphocytes in Macaque
Immunogenetics, 2011Co-Authors: Alice Aarnink, P. A. Apoil, Henri-Jean Garchon, Marie Blancher-Sardou, Bénédicte Puissant-lubrano, Antoine BlancherAbstract:While the number of peripheral blood T lymphocytes and of their two main subsets (CD4+CD8− and CD4−CD8+) varies little in a given healthy individual, substantial variation is observed between individuals. It was proposed that these counts could be influenced by MHC polymorphisms because of the well-established role of MHC molecules in thymic T lymphocyte maturation and presentation of antigenic peptides to peripheral T lymphocytes. To test this hypothesis, we have chosen the Crab-Eating Macaque (Macaca fascicularis), an animal model phylogenetically close to man. We selected the Philippine Macaque population because of a restriction of the MHC polymorphism in this islander population. Peripheral blood lymphocytes were counted with an automated analyzer and T lymphocyte subsets were assessed by immunolabeling and flow cytometry. The MHC polymorphism was investigated in 200 unrelated subjects using 14 microsatellites markers distributed across the MHC and the DRB locus that was genotyped by denaturing gradient gel electrophoresis and sequencing. All markers were in Hardy–Weinberg equilibrium. Allelic associations were tested with the UNPHASED software. We revealed a significant influence of the MHC class II region on CD4+ T lymphocyte blood count with the largest effect associated with a two-locus haplotypes combining the DRACA allele 274 and the DRB haplotype #8a (p
-
Comparison of allele O sequences of the human and non-human primate ABO system
Immunogenetics, 1999Co-Authors: Nathalie Kermarrec, P. A. Apoil, Francis Roubinet, Antoine BlancherAbstract:Like humans, non-human primates express the antigens A and B of the ABO histoblood group system. In chimpanzees, only A and O types are found, while the types A, B, AB, and O are found in Macaques. The sequences of exons 6 and 7 of two chimpanzee O alleles (Odel and Ox), two Macaque species O alleles (rhesus monkey and Crab-Eating Macaque), and sequences of exon 7 of two major chimpanzee A alleles (A1ch and A2ch) were established. The sequences of cDNAs corresponding to the chimpanzee and rhesus monkey O alleles were characterized from exon 1 to 7 and from exon 4 to 7, respectively. A comparison of our results with ABO gene sequences already published by others demonstrates that human and non-human primate O alleles are species-specific and result from independent silencing mutations. These observations reinforce the hypothesis that the maintenance of the ABO gene polymorphism in primates reflects convergent evolution more than transpecies inheritance of ancestor alleles.
-
Characterization of the three immunoglobulin G subclasses of Macaques
Scandinavian Journal of Immunology, 1999Co-Authors: Patrick Calvas, P. A. Apoil, Francis Roubinet, F. Fortenfant, J. Andris, Daniela Capra, Antoine BlancherAbstract:Southern blot experiments with genomic DNA samples of rhesus monkeys and Crab-Eating Macaques and human C gamma-specific probes indicated that the two Macaque species studied here possessed three C gamma genes per haploid genome. By amplifying the cDNA from Macaque-mouse hybridomas, the coding sequences of two different rhesus monkey immunoglobulin (Ig)G subclasses, IgG1rh (Cgamma1rh) and IgG2rh (Cgamma2rh), and one Crab-Eating Macaque IgG subclass IgG1mafa (Cgamma1mafa), were characterized. None of the 16 rhesus monkey-mouse hybridomas studied here secreted IgG of the third subclass IgG3rh (Cgamma3rh). The Cgamma3rh gene was partly characterized at the genomic level. The cDNA of the Cgamma3rh gene was amplified from mRNA of rhesus monkey peripheral blood mononuclear cells (PBMC). The results are analysed in terms of phylogenesis of the C gamma genes. The cDNA sequences coding for the Cmu and the Ckappa domains of rhesus monkey Ig were established and compared to their human and non-human primate counterparts.
-
Structural analysis of the RH-like blood group gene products in nonhuman primates
Immunogenetics, 1995Co-Authors: Isabelle Salvignol, Caroline Kim, W W Socha, Patrick Bailly, Y. Colin, J Ruffie, Patrick Calvas, Jean-pierre Cartron, Antoine BlancherAbstract:Rh-related transcripts present in bone marrow samples from several species of nonhuman primates (chimpanzee, gorilla, gibbon, Crab-Eating Macaque) have been amplified by RT-polymerase chain reaction using primers deduced from the sequence of human RH genes. Nucleotide sequence analysis of the nonhuman transcripts revealed a high degree of similarity to human blood group Rh sequences, suggesting a great conservation of the RH genes throughout evolution. Full-length transcripts, potentially encoding 417 amino acid long proteins homologous to Rh polypeptides, were characterized, as well as mRNA isoforms which harbored nucleotide deletions or insertions and potentially encode truncated proteins. Proteins of 30–40 000 Mr, immunologically related to human Rh proteins, were detected by western blot analysis with antipeptide antibodies, indicating that Rh-like transcripts are translated into membrane proteins. Comparison of human and nonhuman protein sequences was pivotal in clarifying the molecular basis of the blood group C/c polymorphism, showing that only the Pro103Ser substitution was correlated with C/c polymorphism. In addition, it was shown that a proline residue at position 102 was critical in the expression of C and c epitopes, most likely by providing an appropriate conformation of Rh polypeptides. From these data a phylogenetic reconstruction of the RH locus evolution has been calculated from which an unrooted phylogenetic tree could be proposed, indicating that African ape Rh-like genes would be closer to the human RhD gene than to the human RhCE gene.
Chaitip Wanichanon - One of the best experts on this subject based on the ideXlab platform.
-
Stereo architecture of the connective tissue cores of the lingual papillae in the treeshrew (Tupaia glis)
Anatomy and Embryology, 1992Co-Authors: Kan Kobayashi, Chaitip WanichanonAbstract:The stereo architecture of the lingual connective tissue cores (CTC) in the treeshrew ( Tupaia glis ) (which has the primitive characteristics of primates) was observed by scanning electron microscopy, and compared to that of other animal orders. The tongue of the treeshrew has three vallate papillae which are situated in the posterior part of the tongue, while some Macaques have several vallate papillae. Among numerous filiform papillae, fungiform papillae are sporadically distributed. A filiform papilla consists of a bundle of several slender spine-like processes arranged in a circle at the basal margin. After removal of the epithelium, the CTC of the filiform papilla looks like a human hand raised with the palm facing towards the tongue tip. The fungiform CTC in the threeshrew is columnar in shape (rather similar to that of Insectivora and Rodentia) and at the top there are several round depressions for taste buds. In the treeshrew several large rod-shaped processes are derived from the postero-lateral margin of the tongue, as in Carnivora (dogs and cats), where foliate papillae are located in many other animal species. The treeshrew has numerous characteristics similar to those of the Crab-Eating Macaque (Primates), but at the same time it has some characteristics similar to those of Insectivora, Rodentia, Carnivora and Artiodactyla.
Marys-ann Stanley - One of the best experts on this subject based on the ideXlab platform.
-
Population genetics of Crab-Eating Macaques (Macaca fascicularis) on the island of mauritius.
American journal of primatology, 1993Co-Authors: Mikiko Kondo, Yoshi Kawamoto, Ken Nozawa, Kiyoaki Matsubayashi, Tsuyoshi Watanabe, Owen Griffiths, Marys-ann StanleyAbstract:Protein polymorphisms of the Crab-Eating Macaque (Macaca fascicularis) on the island of Mauritius in the southwest Indian Ocean were examined electrophoretically for 201 blood samples. All of the variant types detected were those found previously in the Asian populations. Genetic variability of the island population was estimated to be Ppoly = 16% and H = 6.5%, which was lower than that of the Asian populations. A tendency that a small number of loci were highly polymorphic was observed. These results may reflect the establishment of the island population from a small number of introduced ancestors, or the existence of the bottleneck effect. For the origin of the Mauritian monkeys, comparison of electrophoretic variants suggested that they originated from the Malay Peninsula or the Greater Sunda Islands, especially from Java. Though the homozygous individuals exceeded in number as a whole, a significant subdivision was not detected in the population. © 1993 Wiley-Liss, Inc.
Tim Herrmann - One of the best experts on this subject based on the ideXlab platform.
-
Metamaterial-based transmit and receive system for whole-body magnetic resonance imaging at ultra-high magnetic fields.
PloS one, 2018Co-Authors: Tim Herrmann, Thorsten Liebig, Johannes Mallow, Christian Bruns, Jörg Stadler, Judith Mylius, Michael Brosch, Jan Taro Svedja, Zhichao Chen, Andreas RenningsAbstract:Magnetic resonance imaging (MRI) at ultra-high fields (UHF), such as 7 T, provides an enhanced signal-to-noise ratio and has led to unprecedented high-resolution anatomic images and brain activation maps. Although a variety of radio frequency (RF) coil architectures have been developed for imaging at UHF conditions, they usually are specialized for small volumes of interests (VoI). So far, whole-body coil resonators are not available for commercial UHF human whole-body MRI systems. The goal of the present study was the development and validation of a transmit and receive system for large VoIs that operates at a 7 T human whole-body MRI system. A Metamaterial Ring Antenna System (MRAS) consisting of several ring antennas was developed, since it allows for the imaging of extended VoIs. Furthermore, the MRAS not only requires lower intensities of the irradiated RF energy, but also provides a more confined and focused injection of excitation energy on selected body parts. The MRAS consisted of several antennas with 50 cm inner diameter, 10 cm width and 0.5 cm depth. The position of the rings was freely adjustable. Conformal resonant right-/left-handed metamaterial was used for each ring antenna with two quadrature feeding ports for RF power. The system was successfully implemented and demonstrated with both a silicone oil and a water-NaCl-isopropanol phantom as well as in vivo by acquiring whole-body images of a Crab-Eating Macaque. The potential for future neuroimaging applications was demonstrated by the acquired high-resolution anatomic images of the Macaque's head. Phantom and in vivo measurements of Crab-Eating Macaques provided high-resolution images with large VoIs up to 40 cm in xy-direction and 45 cm in z-direction. The results of this work demonstrate the feasibility of the MRAS system for UHF MRI as proof of principle. The MRAS shows a substantial potential for MR imaging of larger volumes at 7 T UHF. This new technique may provide new diagnostic potential in spatially extended pathologies such as searching for spread-out tumor metastases or monitoring systemic inflammatory processes.
-
High-resolution in vivo imaging of the Macaque’s head.
2018Co-Authors: Tim Herrmann, Thorsten Liebig, Johannes Mallow, Christian Bruns, Jörg Stadler, Judith Mylius, Michael Brosch, Jan Taro Svedja, Zhichao Chen, Andreas RenningsAbstract:(A) Sketch of the experimental setup with one ring antenna for transmit and an additional ring antenna acting as a wave reflector for improving the directivity of the electromagnetic waves for head imaging when using the 3-element, phased-array head receive coil. (B) In vivo MR image acquired with the system depicted in Fig 6A. The high-resolution images show a detailed view of the main parts of the Crab-Eating Macaque brain (gray and white matter, cerebellum, and hippocampus). In the upper left corner a small back-folding artifact is visible which does not affect the imaging of the brain parts. The ticks indicate the distance to the y and z position of the iso-center of the MRI system.
-
Ultra-high field MRI for primate imaging using the travelling-wave concept
Magnetic Resonance Materials in Physics Biology and Medicine, 2013Co-Authors: Johannes Mallow, Tim Herrmann, Judith Mylius, Michael Brosch, Kyoung-nam Kim, Joerg Stadler, Johannes BernardingAbstract:Object Ultra-high field (UHF) neuroimaging is usually conducted with volume transmit (Tx) and phased array receive (Rx) coils, both tightly enclosing the object. The travelling-wave (TW) concept allows a remote excitation offering more flexible experimental setups. To investigate the feasibility of primate MRI in horizontal UHF MRI, we first compared the distribution of the electromagnetic fields in an oil phantom and then verified the concept with an in vivo experiment. Materials and methods In the phantom experiments an in-house circularly polarized hybrid birdcage coil and a self-developed patch antenna were used for Tx and an eight-element phased array antenna for Rx. B _1 ^+ fields were calculated and measured for both approaches. For in vivo experiments the Rx part was replaced with an optimized three-element phased array head coil. The SAR was calculated using field simulation. Results In the phantom the field distribution was homogenous in a central volume of interest of about 10 cm diameter. The TW concept showed a slightly better homogeneity. Examination of a female Crab-Eating Macaque led to homogeneous high-contrast images with a good delineation of anatomical details. Conclusion The TW concept opens up a new approach for MRI of medium-sized animals in horizontal UHF scanners.
Isabelle Salvignol - One of the best experts on this subject based on the ideXlab platform.
-
Structural analysis of the RH-like blood group gene products in nonhuman primates
Immunogenetics, 1995Co-Authors: Isabelle Salvignol, Caroline Kim, W W Socha, Patrick Bailly, Y. Colin, J Ruffie, Patrick Calvas, Jean-pierre Cartron, Antoine BlancherAbstract:Rh-related transcripts present in bone marrow samples from several species of nonhuman primates (chimpanzee, gorilla, gibbon, Crab-Eating Macaque) have been amplified by RT-polymerase chain reaction using primers deduced from the sequence of human RH genes. Nucleotide sequence analysis of the nonhuman transcripts revealed a high degree of similarity to human blood group Rh sequences, suggesting a great conservation of the RH genes throughout evolution. Full-length transcripts, potentially encoding 417 amino acid long proteins homologous to Rh polypeptides, were characterized, as well as mRNA isoforms which harbored nucleotide deletions or insertions and potentially encode truncated proteins. Proteins of 30–40 000 Mr, immunologically related to human Rh proteins, were detected by western blot analysis with antipeptide antibodies, indicating that Rh-like transcripts are translated into membrane proteins. Comparison of human and nonhuman protein sequences was pivotal in clarifying the molecular basis of the blood group C/c polymorphism, showing that only the Pro103Ser substitution was correlated with C/c polymorphism. In addition, it was shown that a proline residue at position 102 was critical in the expression of C and c epitopes, most likely by providing an appropriate conformation of Rh polypeptides. From these data a phylogenetic reconstruction of the RH locus evolution has been calculated from which an unrooted phylogenetic tree could be proposed, indicating that African ape Rh-like genes would be closer to the human RhD gene than to the human RhCE gene.
