PubMed Health⌕ Search

Biomedical subjects

M Vaiman

Publications and source records attributed to M Vaiman.

At least 37 records · Page 2Linked to original sources
PubMed1995

Distinct tissue distribution in pigs of tenascin-X and tenascin-C transcripts.

Tenascin-X and tenascin-C glycoproteins are phylogenetically conserved components of the extracellular matrix, although their specific roles remain to be determined. cDNA probes were produced from pig tenascin-X and tenascin-C genes and were used to examine the tissue distribution of the transcripts in 28 tissues from Large-White pigs, 4.5-42-months old (called adults) and 17 tissues from 87-day-old fetuses. The hybridization of Northern blots with tenascin-X probes revealed, in most tissues, a complex pattern of bands including a major band of about 13 kb, assumed to correspond to the main tenascin-X transcript. Hybridization with the tenascin-C probe showed two transcripts of 6.8 kb and 8.2 kb. The data from the ribonuclease-protection technique showed that both genes displayed large variations in the transcription levels among the tissues analysed. Overall, the tenascin-X gene was significantly expressed in two thirds of the tissues, and the tenascin-C gene in about 50% of them. The highest tenascin-X signals were observed in tendons, ligaments and, unexpectedly, in peripheral nerves. Other tissues, including colon, dermis, skin, heart, uterus, stomach, jejunum, placentae, aorta, lung, mammary and adrenal glands also exhibited significant signal intensities. In fetuses, mainly testes and skeletal muscle showed higher transcription levels than the adult counterparts. The tenascin-C gene was predominantly transcribed in the ligament, tendon, adrenal gland and colon, and more weakly in the stomach, jejunum, lung and spinal cord. In fetuses, the tenascin-C signal in the brain was higher than the signal in the brain of adult, whereas the reverse was true for the adrenal gland and the colon. Within a given tissue, the level of tenascin-X and tenascin-C transcripts varied greatly, indicating independent tenascin-X and tenascin-C transcription regulation mechanisms; this was particularly obvious in adult and fetal nerves but also in the dermis, skin, heart, uterus, placentae and aorta, where tenascin-X RNA molecules were much more abundant than those of tenascin-C. In addition, similar differences were observed in the skeletal muscle and adrenal gland of fetuses. In contrast, the amount of tenascin-C transcripts in the fetal brain and adult spinal cord was higher than those for tenascin-X. Our results draw attention to a possible specific role of tenascin-X in the peripheral nerve physiology.

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↗
PubMed1995

The BAT1 gene in the MHC encodes an evolutionarily conserved putative nuclear RNA helicase of the DEAD family.

The BAT1 gene has previously been identified about 30 kb upstream from the tumor necrosis factor (TNF) locus and close to a NF kappa b-related gene of the nuclear factor family in the major histocompatibility complex (MHC) of human, mouse, and pig. We now show that the BAT1 translation product is the homolog of the rat p47 nuclear protein, the WM6 Drosophila gene product, and probably also Ce08102 of Caenorhabditis elegans, all members of the DEAD protein family of ATP-dependent RNA helicases. This family has more than 40 members, including the eukaryotic translation initiation factor-4A (eIF-4A), the human nuclear protein p68, and the Drosophila oocyte polar granule component vasa. BAT1 spans about 10 kb, is split into 10 exons of varying length, and encodes a protein of 428 amino acids (approximately 48 kDa). Human and pig BAT1 cDNAs display 95.6% identity in the coding region and 80% identity in the 5' and 3' noncoding regions. Several repeat sequences of different types were identified in introns of the porcine BAT1 gene. Three different mRNAs, 4.1, 1.7, and 0.9 kb, respectively, were detected in all tissues analyzed upon hybridization with porcine BAT1 cDNA. Transfection and expression of human BAT1 cDNA after tagging with a heterologous antibody recognition epitope revealed a nuclear localization of the hybrid protein. An MspI RFLP was detected in an SLA class I typed family, confirming the localization of the BAT1 gene in the porcine MHC. BAT1 thus encodes a putative nuclear ATP-dependent RNA helicase and is likely to have an indispensable function.

Amino Acid Sequence↗
PubMed1995

Individual differences in cell-mediated and humoral immunity in pigs.

Previous experiments displayed consistent individual behavioural differences in pigs. Some showed a more active behavioural response (aggressive and resistant; so-called A/R pigs), other a more passive behavioural response (non-aggressive and non-resistant; so-called NA/NR pigs). Moreover, these behavioural coping strategies were associated with different behavioural, physiological and endocrine responses under stress conditions. In the present study we selected 32 A/R and 32 NA/NR individuals and tested their immune reactivity in reaction to stress using several cell-mediated (CMI) and humoral immunological tests. Active A/R pigs had a higher in vivo and in vitro CMI to nonspecific and specific antigens, while after stress CMI reduced more in A/R than in NA/NR pigs. In contrast, humoral immunity was highest in NA/NR pigs. Furthermore, some serologically typed swine lymphocyte antigen (SLA) class I haplotypes were not equally distributed between A/R and NA/NR pigs. In general, these findings show that measurement of immune reactivity is an important tool to define how animals cope with environmental demands.

Animals↗
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

Frequency of interferon-alpha-secreting blood leukocytes in irradiated and bone-marrow-grafted pigs.

The effects of irradiation were studied on porcine interferon-alpha (IFN-alpha) secreting cells (IFN-alpha SC). IFN-alpha SC were characterized by an ELISPOT assay on non-adherent PBMC following incubation with the transmissible gastroenteritis coronavirus. In vitro irradiation of PBMC was followed by a decrease in the number of IFN-alpha SC while IFN-gamma production and cell viability were not affected. These data indicate that porcine IFN-alpha SC are relatively radiosensitive. Indeed, the frequency of blood IFN-alpha SC decreased markedly and rapidly after in vivo whole body or partial lymphoid irradiation. In addition, within several days of compatible bone-marrow engraftment in the irradiated animals, the number of blood IFN-alpha SC returned to normal values. These data demonstrate that circulating porcine IFN-alpha SC are derived from bone-marrow progenitors.

Animals↗
PubMed1994

Characterization of six new loci within the swine major histocompatibility complex class III region.

A search for new potential coding sequences was conducted within two overlapping cosmid genomic DNA clusters of about 170 and 45 kb from the swine major histocompatibility complex class III region. The sequences were detected with various probes, including pools of swine cDNA, homologous and heterologous genomic sequences, and synthetic oligonucleotides. The 170 kb cluster was centered on the tumor necrosis factor genes (TNF), and the 45 kb cluster contained the heat-shock protein 70 genes (HSP70). The TNF cluster revealed the presence of five new genes: lymphotoxin beta, BAT1, BAT2, BAT3, and a sequence related to DNA-binding factors. No sequence homologous to B144 was found in the TNF cluster, although other unidentified coding sequences may be present in this cluster. The HSP70 cluster contained a gene identified as BAT6, that is, tRNA-valyl synthetase. These results provide new evidence that the genomic maps of these various genes in the TNF and HSP70 sub-regions are similar in swine and human.

Animals↗
PubMed1993

Characterization of a polymorphic heat shock protein 70 gene in swine outside the SLA major histocompatibility complex.

To characterize a hitherto unidentified swine Hsp70 gene, a cDNA library was prepared from total RNA isolated from swine lymphocytes and heat-shocked at 42 degrees C for 2 h. One positive clone with a 2.6 kb insert was found. Its sequencing revealed a maximum homology with the human inducible Hsp70B' gene. The genomic polymorphism of this insert was investigated by restriction fragment length polymorphism (RFLP) in an informative family for the major histocompatibility complex SLA. Digestion with PvuII generated 8 bands which were common to both parents, and for the male two extra bands at 0.69 and 0.64 kb. After digestion with PstI, there was also an extra band at 1.6 kb for the male in addition to the seven bands common to both parents. The eleven offsprings' RFLP patterns exhibited all the common parental bands, but four piglets displayed the male's specific bands in addition. All the polymorphic bands belonged to the same locus and segregated independently of SLA. Restriction mapping of the Hsp70 gene indicated the absence of introns, and showed that the polymorphic PstI site was located upstream of the gene's 5' coding region, and the PvuII site inside its coding region.

Amino Acid Sequence↗
PubMed1993

Accurate characterization of porcine bivariate flow karyotype by PCR and fluorescence in situ hybridization.

The 19 chromosomal pairs of the swine karyotype are resolved into 18 peaks denoted A to Q and Y by dual-beam flow cytometry. The chromosomal content of six peaks has previously been determined by analyzing male/female differences, karyotypes of animals carrying translocations, and PCR studies of genes with known assignments. For the remaining chromosomes, putative assignments to flow peaks were deduced from comparison of DNA contents, determined by flow cytometry, and chromosomal size. We present here the complete characterization of the pig bivariate flow karyotype using the PARM-PCR technique combined with fluorescence in situ hybridization. Chromosome-specific probes were generated by PCR amplification of 300 sorted chromosomes with primers under nonspecific conditions and used to paint chromosomes by FISH. The chromosomal content of each peak was identified: peaks A (chromosome 1), B (13), C (6), D (2), E (14), F (3), G (7), H (9,4,X), H1 (9), I (15), J (8), K (5), L (10), M (12), N (16), O (11), P (17), Q (18), Y (Y). We were able to characterize perfectly the pig bivariate flow karyotype. Such techniques could be applied to any other species.

Animals↗
PubMed1993

Isolation of four HSP70 genes in the pig and localization on chromosomes 7 and 14.

For insight into the general organization of the swine leukocyte antigen (SLA) complex, the swine major histocompatibility complex (MHC), four sequences related to the heat-shock proteins HSP70 were characterized by screening of a pig genomic cosmid library with a swine cDNA HSP70 2.6-kb probe. This yielded three positive clones: HC2.2, HC3.2, and HC4.2. Restriction site maps revealed a large overlap of HC2.2 with HC3.2, whereas HC4.2 was independent. Southern blot hybridization with the 5' section, the central section, and the 3' section of the 2.6-kb probe and also with a swine 4.5-kb HSP70 genomic probe suggested the existence, within the overlapping clones, of three distinct HSP70 sequences encompassing a segment no longer than 22 kb. The HC4.2 clone, which hybridized with the same probes, displayed a single band of 7.3 kb, probably corresponding to one gene only. Fluorescent in situ hybridization on swine chromosome metaphases with the whole HC2.2 or HC4.2 cosmids allowed the assignment of HC2.2 to MHC region on Chromosome (Chr) 7 (Cen-p1.1), and of HC4.2 to Chr 14 (q2.4-2.5). Thus, as in humans, the swine MHC comprises three closely linked HSP70 loci. The presence of additional genes belonging to the same inducible HSP70 gene family can be expected from what is known in humans. The HSP70 gene found here on the pig Chr 14 may be one of these putative unidentified genes.

Animals↗
PubMed1993

A PCR-based method to amplify DNA with random primers: determining the chromosomal content of porcine flow-karyotype peaks by chromosome painting.

We present here a new PCR-based technique that allows the production of several micrograms of DNA from only 300 flow-sorted chromosomes. During the first two PCR cycles, the annealing temperature is decreased to 30 degrees C, and numerous random loci are amplified under nonspecific conditions. As demonstrated here for pig chromosomes 1 and 18, the PCR products may be used to identify the chromosomal content of the flow-karyotype peaks of any species by fluorescence in situ hybridization.

Animals↗
PubMed1992

Sequences of the swine 21-hydroxylase gene (CYP21) and a portion of the opposite-strand overlapping gene of unknown function previously described in human.

We sequenced a 4.8 kb BamHI swine genomic fragment comprising the entire 21-hydroxylase gene (CYP21) and its 5' and 3' flanking segments. The CYP21 coding sequence spanned 3050 bp and as in other species, comprised 10 exons separated by the corresponding introns. The deduced protein corresponded to 492 amino acid residues, 8 of which differed from a previously sequenced swine CYP21 enzyme. The 5' flanking region displayed several putative cis-acting elements which may be involved in either constitutive or cyclic adenosine 3',5'-monophosphate (cAMP) dependent transcriptional expression. We also characterized within the 5' region a 139 bp repetitive element of the short interspersed nucleotide element (SINE) family located on the opposite strand. In addition, we characterized the last five exons of a human-like opposite strand gene (OSG/X) located in the swine at the 3' end of CYP21. The sequenced part of this OSG/X displayed a very strong homology with its human counterpart.

Amino Acid Sequence↗
PubMed1992

Swine chromosomal DNA quantification by bivariate flow karyotyping and karyotype interpretation.

Human and swine chromosomes were analyzed separately and as a mix to obtain bivariate flow karyotypes. They were normalized to each other in order to use the human chromosomal DNA content as standard. Our results led to the characterization of the "DNA line" in swine identical to the human "DNA line." Estimation of the DNA content in mega-base pairs of the swine chromosomes is proposed. Chromosomal assignment to the various resolved peaks on the bivariate swine flow karyotype is suggested from the relation between DNA content quantified by flow cytometry and chromosomal size. Swine chromosomes 1, 13, 6, 5, 10, 16, 11, 18, and Y were assigned to peaks A, B, C, K, L, N, O, Q, and Y, respectively. Peaks D and E were assumed to contain chromosomes 2 and 14, but without specific assignment. Similarly, P and M peaks were expected to correspond to chromosomes 12 and 17. Of the remaining chromosomes (3, 7, X, 8, 15, 9, and 4), chromosomes 3, 7, and X, which were assigned previously to peaks F, G, and H, respectively, led us to deduce that chromosomes 15 and 8 belonged to peaks I and J, and chromosomes 9, 4, and X to peak H.

Animals↗
PubMed1992

Pig standard bivariate flow karyotype and peak assignment for chromosomes X, Y, 3, and 7.

A standard pig flow karyotype (2N = 38 chromosomes) was defined by standardization of several flow karyotypes obtained from stimulated peripheral blood lymphocytes of normal male and female pigs. Depending on the animals under study, the flow analysis of their chromosome suspensions gave rise to bivariate flow karyotypes comprising from 15 to 17 peaks, of which 11 to 15 represented single chromosomes. The results were used to propose a peak nomenclature. In addition, a male miniature pig lymphoblastoid cell line was characterized by flow cytogenetics. A very high-resolution flow karyotype, in which all peaks but one superimposed on those of the standard karyotype, was obtained. Peaks were assigned for chromosomes X and Y. Analysis of flow karyotypes obtained from translocated t(3,7)(p1.3;q2.1) pigs combined with polymerase chain reaction (PCR) studies of major histocompatibility complex (MHC)-linked sequences on flow-sorted chromosomes allowed identification of peaks 3 and 7 of normal pig chromosomes and of the derivative chromosomes associated with the t(3,7)(p1.3;q2.1) translocation.

Animals↗
PubMed1992

Anti-major histocompatibility complex antibody removal assay in a swine model.

A swine model of anti-MHC (SLA) immunization by skin grafting was established with the aim of removing preformed anti-MHC antibodies and preventing their resynthesis, in a situation close to that of hyperimmunization in humans. Plasma exchange therapy with or without associated immunosuppressive therapy was used. The feasibility of this animal model in terms of anti-MHC immunization and its therapeutic management have been proven. However, frequent early deaths of animals still mar the experimental protocol. Synchronization of plasma exchange and subsequent cyclophosphamide pulses seemed to abolish the antibody rebound phenomenon and cause marked drop of anti-MHC antibodies. Restimulation by a new skin graft is responsible for an intense polyclonal antibody stimulation, which suggests that we have to be careful in grafting patients with positive historical crossmatches and negative current ones.

Animals↗