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Biomedical subjects

M Riviere

Publications and source records attributed to M Riviere.

At least 19 recordsLinked to original sources
PubMed2005

Discrimination between closed and open forms of lipases using electrophoretic techniques.

The enhanced catalytic activity of lipases is often associated with structural changes. The three-dimensional (3D) structures showed that the covalently inhibited lipases exist under their open conformations, in contrast to their native closed forms. We studied the inhibition of various lipases--human and dog gastric lipases, human pancreatic lipase, and Humicola lanuginosa lipase--by the octyl-undecyl phosphonate inhibitor, and we measured the subsequent modifications of their respective electrophoretic mobility. Furthermore, the experimental values of the isoelectric points found for the native (closed) and inhibited (open) lipases are in agreement with theoretical calculations based on the electrostatic potential. We concluded that there is a significant difference in the isoelectric points between the closed (native) and open (inhibited) conformations of the four lipases investigated. Thus, analysis of the electrophoretic pattern is proposed as an easy experimental tool to differentiate between a closed and an open form of a given lipase.

Animals↗
PubMed2003

In vitro lipolysis by human pancreatic lipase is specifically abolished by its inactive forms.

In human adults, the enzymatic hydrolysis of dietary fat along the digestive tract is sequentially catalyzed by two main enzymes, human gastric lipase (HGL) and human pancreatic lipase (HPL). Both a chemically inhibited form of HPL as well as an inactive HPL mutant with a glycine residue substituted for its catalytic serine were found to be strong inactivators of HPL activity. In the presence of bile salts, this inhibition was clearly due to competition for colipase. We established that the chemically inhibited HPL, probably in its open conformation, had a much greater affinity for colipase than the closed native form of HPL. These inhibitory effects are quite substantial, because a 0.2-M excess of the chemically inhibited HPL form relative to HPL reduced the catalytic lipolytic activity by 50% in the presence of an equimolar amount of colipase.

Anthracenes↗
PubMed1999

Deglycosylation of the 45/47-kilodalton antigen complex of Mycobacterium tuberculosis decreases its capacity to elicit in vivo or in vitro cellular immune responses.

A protection against a challenge with Mycobacterium tuberculosis is induced by previous immunization with living attenuated mycobacteria, usually bacillus Calmette-Guérin (BCG). The 45/47-kDa antigen complex (Apa) present in culture filtrates of BCG of M. tuberculosis has been identified and isolated based on its ability to interact mainly with T lymphocytes and/or antibodies induced by immunization with living bacteria. The protein is glycosylated. A large batch of Apa was purified from M. tuberculosis culture filtrate to determine the extent of glycosylation and its role on the expression of the immune responses. Mass spectrometry revealed a spectrum of glycosylated molecules, with the majority of species bearing six, seven, or eight mannose residues (22, 24, and 17%, respectively), while others three, four, or five mannoses (5, 9, and 14%, respectively). Molecules with one, two, or nine mannoses were rare (1.5, 3, and 3%, respectively), as were unglycosylated species (in the range of 1%). To eliminate the mannose residues linked to the protein, the glycosylated Apa molecules were chemically or enzymatically treated. The deglycosylated antigen was 10-fold less active than native molecules in eliciting delayed-type hypersensitivity reactions in guinea pigs immunized with BCG. It was 30-fold less active than native molecules when assayed in vitro for its capacity to stimulate T lymphocytes primed in vivo. The presence of the mannose residues on the Apa protein was essential for the antigenicity of the molecules in T-cell-dependent immune responses in vitro and in vivo.

Animals↗
PubMed1998

An analysis of extended survival in patients with amyotrophic lateral sclerosis treated with riluzole.

BACKGROUND: In an attempt to better understand and define the progression of amyotrophic lateral sclerosis (ALS), we developed a classification of 5 discrete health states that reflect patients' activities of daily living. These health states were used to determine whether patients with ALS who are treated with riluzole differed from those treated with placebo. SETTING: Clinics for patients with ALS. DESIGN: Placebo-controlled trial of riluzole treatment in 959 patients with ALS. INTERVENTIONS: Treatment with riluzole or placebo. MAIN DEPENDENT MEASURES: A Cox model was used to assess whether, from the initial randomization to the end of an 18-month follow-up, there was a difference in the times of transition into subsequent health states between patients treated with riluzole and those treated with placebo. RESULTS: Our analysis showed a significant difference in the time to transit between the riluzole and the placebo groups in less severely affected cases, ie, state 2 and state A (the milder states) of ALS. CONCLUSION: Patients receiving riluzole remained in the milder health states longer (P<.05).

Amyotrophic Lateral Sclerosis↗
PubMed1994

The genes encoding the glutamate receptor subunits KA1 and KA2 (GRIK4 and GRIK5) are located on separate chromosomes in human, mouse, and rat.

The chromosomal localization of the human and rat genes encoding the kainate-preferring glutamate receptor subunits KA1 and KA2 (GRIK4 and GRIK5, respectively) was determined by Southern analysis of rat x mouse and human x mouse somatic cell hybrid panels and by fluorescence in situ hybridization. The localization of the mouse genes (Grik4 and Grik5) was established by interspecific backcross mapping. GRIK4 and GRIK5 are located on separate chromosomes (Chrs) in all species. GRIK4 mapped to human Chr 11q22.3, mouse Chr 9, and rat Chr 8. GRIK5 mapped to human Chr 19q13.2, mouse Chr 7, and rat Chr 1. The genes encoding the (R,S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-preferring subunit GluR4, or GluRD (GRIA4), the neural cell adhesion molecule (NCAM), the D2 dopamine receptor (DRD2), and the Thy-1 cell surface antigen (THY1) have all been previously mapped to the human Chr 11q22 region. The mapping of the human GRIK4 and GRIK5 genes confirms and extends the relationship between human Chr 11 and mouse Chr 9 and also human Chr 19 and mouse Chr 7. GRIK4 is the fifth gene shared by human Chr 11 and rat Chr 8, whereas GRIK5 is 1 out of the 12 genes that are located on both human Chr 19 and rat Chr 1. Our data extend the conserved synteny established between certain human, mouse, and rat Chrs.

Animals↗
PubMed1994

Localization of the gene for DNA polymerase epsilon (POLE) to human chromosome 12q24.3 and rat chromosome 12 by somatic cell hybrid panels and fluorescence in situ hybridization.

DNA polymerase epsilon [DNA pol epsilon (EC 2.7.7.7)] is one of the four nuclear DNA polymerases in eukaryotic cells. The mammalian enzyme is involved in DNA repair and possibly also in replication of chromosomal DNA. The gene encoding pol epsilon (POLE) was assigned to human and rat chromosomes 12 by Southern blot analysis of genomic DNA from mouse-human and mouse-rat somatic cell hybrid panels using human cDNA probe. The human gene was then regionally localized to band 12q24.3 by fluorescence in situ hybridization of metaphase spreads of chromosomes from human lymphocytes using genomic DNA probe. POLE is closely linked to HNF1A, a gene encoding a liver-enriched transcription factor, HNF1 alpha. The two genes thus define a new synteny group retained on human and rat chromosomes 12. Another gene mapping to the same or close-by region as human POLE is a gene for inherited disorder tuberous sclerosis 3, TSC3.

Animals↗
PubMed1994

The complete DNA sequence and the genetic organization of the short unique region (US) of the bovine herpesvirus type 1 (ST strain).

The DNA sequence of bovine herpesvirus type 1 (BHV-1) ST strain (BHV-1.2 subtype) entire unique short (US) region and part of adjacent flanking sequences of the inverted repeats was determined. The BHV-1 ST US region is 9745 bp in size and has a 70.5% G + C content. Eight potential open reading frames (ORFs) longer than 100 amino acids and designated ORF1 to ORF8 were identified on this sequence. Seven of these had counterparts in the US of herpes simplex type 1 (HSV-1), pseudorabies virus (PRV), and equine herpesvirus type 1 (EHV-1). BHV-1 ORF2 encodes a protein homologous to HSV-1 US2; ORF3 putative protein exhibits homology with HSV-1 US3 (serine-threonine protein kinase); ORF4 encodes a putative glycoprotein homologous to PRV gG (gX) and EHV-1 gG (gX); ORFs 5,6, and 7 encode respectively HSV-1 glycoproteins gD, gl, and gE homologues; and ORF8 codes for a putative homologue of HSV-1 US9. Although BHV-1 ST strain apparently lacks a HSV-1 US1 homologue, the genetic content and the genomic organization of its US region was found to be similar to the general organization already described for HSV-1, EHV-1, PRV, and avian herpesviruses HVT and MDV US regions. In fact, the BHV-1 US region genomic organization is the closest to the general consensus determined from the comparison of known alphaherpesvirus US regions.

Amino Acid Sequence↗
PubMed1993

Improved purification and biochemical characterization of phospholipase D from cabbage.

Phospholipase D (phosphatidylcholine phosphatidohydrolase, EC 3.1.4.4) was purified from cabbage leaves. The two step purification procedure involved hydrophobic chromatography on Octyl-Sepharose followed by a Mono-Q/FPLC-column with a total yield of 23% and a purification factor of 1000. A zymographic assay was used to detection of PL D activities at various stages of purification under non denaturing PAGE. The molecular mass was determined to be 90 kDa using the SDS/PAGE method, and 90,200 Da as calculated from the amino acid analysis. The isoelectric point of the enzyme is acidic (pI = 4.7). The amino-acid composition and 29 residues of the NH2-terminal amino-acid sequence were determined.

Amino Acid Sequence↗
PubMed1993

Structures and chromosomal localizations of two rat genes encoding S-adenosylmethionine decarboxylase.

S-Adenosylmethionine decarboxylase (AdoMetDC) is a ubiquitous enzyme in eukaryotic cells and responds to a wide variety of stimuli affecting growth. To provide a framework for understanding the molecular basis of the mechanisms responsible for regulating the expression of this enzyme activity, we recently cloned and sequenced the rat gene for AdoMetDC. Now we have isolated another, slightly different AdoMetDC gene from a rat genomic library. Comparison of the two genes shows a high degree of conservation of sequence and structural organization. The two genes share the following characteristics: (1) both are approximately 16 kb in size, have identical exon/intron boundaries, and exhibit similar intron/exon structural organization; and (2) the nucleotide sequences are highly conserved in the coding regions and in many introns. Analysis of mouse-rat somatic cell hybrids has localized both rat genes to chromosome 20. The most interesting feature of these genes is that their 5' flanking regions are totally different. The promoter activities of the 5' regulatory regions were assessed by transient gene expression assays in Rat-2 cells after fusion to the chloramphenicol acetyltransferase gene. Transient transfections with the chimeric DNAs demonstrated that these fragments were able to function as efficient promoters, indicating that the diverging 5' regions of two AdoMetDC genes contain functional, but different, regulatory transcription elements.

Adenosylmethionine Decarboxylase↗
PubMed1993

Vaccination of pigs against pseudorabies with highly attenuated vaccinia (NYVAC) recombinant viruses.

Poxvirus recombinants, based on the highly attenuated NYVAC strain of vaccinia virus (Tartaglia et al., 1992), containing single gene inserts encoding the pseudorabies virus (PRV) gII, gIII, or gp50 glycoproteins were tested for their immunogenicity in pigs. Twenty-four pigs were randomly divided into six groups of four. Groups 1-3 were inoculated with 10(7) CCID50 of NYVAC/PRV gII, NYVAC/PRV gIII, or NYVAC/PRV gp50, respectively, while groups 4 and 5 received the NYVAC parent virus or an inactivated PRV vaccine control, respectively. Group 6 represented the sham vaccinated control group. All inoculations were given by the intramuscular route on weeks 0 and 4. The candidate vaccines were shown to be safe with no local or systemic reactions. At 4 weeks following the second inoculation, all pigs were challenged by an oronasal administration of a virulent PRV strain. Pigs were monitored before and after challenge for clinical manifestations resulting from vaccination and challenge exposure, respectively. Sera were analyzed for PRV neutralizing activity. Virological analyses after challenge included assessment of virus shedding and the development of latent PRV infections. All but one animal developed latent PRV infection following challenge exposure; however, significant protection against PRV-induced signs was afforded by vaccination with either the NYVAC/PRV gp50 or NYVAC/PRV gII recombinant viruses, as well as with the inactivated PRV vaccine. The NYVAC/PRV gp50 also reduced overall virus shedding after challenge. The extent of protection against PRV-induced clinical signs, in general, was associated with the level of pre-challenge virus neutralizing activity.

Animals↗
PubMed1993

The complete sequence and gene organization of the short unique region of herpesvirus of turkeys.

The DNA sequence of the whole of the short unique region (U(s)) and that of part of the short terminal repeat (TRs) of herpesvirus of turkeys (HVT) were determined. HVT U(s) is 8.6 kbp long and contains eight potential open reading frames (ORFs). Seven of these have counterparts in the U(s) of herpes simplex virus type 1 (HSV-1). The homologous proteins include US1, US2, US10, protein kinase (US3) and the glycoproteins gD, gI and gE. In addition, HVT contains one ORF which has a counterpart in the U(s) of Marek's disease virus (MDV) but is not homologous to any other known herpesvirus gene. Although HVT and MDV proteins encoded by U(s) genes have evident similarities with proteins encoded by alphaherpesviruses, multiple alignment analysis of predicted amino acid sequences show that HVT proteins are more closely related to MDV proteins than to homologous proteins of mammalian alphaherpesviruses. The percentage amino acid identity between HVT and MDV U(s)-encoded proteins ranges from 35 to 65, the most conserved protein being encoded by the homologues of the HSV-1 US2 gene. Most of the genes are colinear with those of HSV-1 except US10 which is transposed in HVT and MDV. A characteristic feature of HVT is the fact that approximately two-thirds of the gE gene is located in the inverted repeats flanking U(s).

Amino Acid Sequence↗
PubMed1992

Specific binding of phenolic glycolipid antigens from Mycobacterium bovis BCG with antibodies.

We studied the molecular binding specificity of two rabbit polyclonal sera generated against phenolic glycolipid antigens namely PheG1 B and PheG1 B-3 from Mycobacterium bovis BCG. PheG1 B is the well-known mycoside B (2-O-Me-alpha-L-Rhap 1----aglycone), while PheG1 B-3 is a recently found glycolipid (alpha-L-Rhap-(1----3)-2-O-Me-alpha-L-Rhap 1----aglycone). The interaction specificity was mainly explained in terms of the cavity volume of the antibodies paratope. The anti-PheG1 B antibodies paratope fits the 2-O-Me-alpha-L-Rhap ligand, while that of anti-PheG1 B-3 binds the disaccharide moiety of PheG1 B-3, and, with a higher affinity, the monosaccharidic unit localized at the non-reducing end. The B-3 antigen affinity is higher than that of antigen B for their homologous antibodies. This can be explained by the fact that the antibodies against phenolic glycolipid B-3 bind optimally to two sequential glycosyl residues suggesting the presence of two subsites. The immunoglobulin subsite with the major affinity binds the monosaccharidic unit localized at the non-reducing end.

Animals↗
PubMed1992

NYVAC: a highly attenuated strain of vaccinia virus.

A highly attenuated vaccinia virus strain, NYVAC (vP866), was derived from a plaque-cloned isolate of the Copenhagen vaccine strain by the precise deletion of 18 open reading frames (ORFs) from the viral genome. Among the ORFs deleted from NYVAC (vP866) are two genes involved in nucleotide metabolism, the thymidine kinase (ORF J2R) and the large subunit of the ribonucleotide reductase (ORF I4L); the gene encoding the viral hemagglutinin (ORF A56R); the remnant (ORF A26L) of a highly expressed gene responsible for the formation of A-type inclusion bodies; the disrupted gene (ORFs B13R/B14R) normally encoding a serine protease inhibitor; and a block of 12 ORFs bounded by two known viral host range regulatory functions (ORFs C7L through K1L). Within this block a secretory protein (ORF N1L) implicated in viral virulence and a functional complement 4b binding protein (ORF C3L) are encoded. The ORFs were deleted in a manner which prevents the synthesis of undesirable novel gene products. The attenuation characteristics of the derived NYVAC strain were compared in in vitro and in vivo studies with those of the Western Reserve (WR) laboratory strain, the New York City Board of Health vaccine strain (Wyeth), the parental plaque-cloned isolate (VC-2) of the Copenhagen vaccine strain used to derive NYVAC, and the avipox virus canarypox (ALVAC), which is naturally restricted for replication to avian species. The NYVAC strain was demonstrated to be highly attenuated by the following criteria: (a) no detectable induration or ulceration at the site of inoculation on rabbit skin; (b) rapid clearance of infectious virus from the intradermal site of inoculation on rabbit skin; (c) absence of testicular inflammation in nude mice; (d) greatly reduced virulence as demonstrated by the results of intracranial challenge of both 3-week-old or newborn mice; (e) greatly reduced pathogenicity and failure to disseminate in immunodeficient (nude or cyclophosphamide treated) mice; and (f) dramatically reduced ability to replicate on a variety of human tissue culture cells. Despite these highly attenuated characteristics, the NYVAC strain, as a vector, retains the ability to induce strong immune responses to extrinsic antigens.

Animals↗
PubMed1992

Chromosomal localization in man and rat of the genes encoding the liver-enriched transcription factors C/EBP, DBP, and HNF1/LFB-1 (CEBP, DBP, and transcription factor 1, TCF1, respectively) and of the hepatocyte growth factor/scatter factor gene (HGF).

By means of somatic cell hybrids segregating either human or rat chromosomes, we determined the chromosome localization of three genes encoding transcription factors expressed in hepatocytes, namely, C/EBP (CCAAT/enhancer binding protein), DBP (D site of albumin promoter binding protein), and HNF1/LFB-1 (designated transcription factor 1, gene symbol: TCF1), and of the hepatocyte growth factor gene, which is identical to the mitogenic and chemotactic factor designated scatter factor (gene symbol:HGF). The CEBP and DBP genes, encoding two related transcription factors, were found to be syntenic both on human chromosome 19 and on rat chromosome 1. These results provide further evidence for conservation of synteny on these two chromosomes (and on mouse chromosome 7). The TCF1 gene was found to be located on chromosome 12 in both man and rat, thereby defining a new segment of homology between these two species (and a segment of mouse chromosome 5). The HGF gene was mapped to rat chromosome 4, confirming homology between this chromosome and human chromosome 7, which carries the human HGF gene.

Animals↗
PubMed1992

Protection of mice and swine from pseudorabies virus conferred by vaccinia virus-based recombinants.

Glycoproteins gp50, gII, and gIII of pseudorabies virus (PRV) were expressed either individually or in combination by vaccinia virus recombinants. In vitro analysis by immunoprecipitation and immunofluorescence demonstrated the expression of a gII protein of approximately 120 kDa that was proteolytically processed to the gIIb (67- to 74-kDa) and gIIc (58-kDa) mature protein species similar to those observed in PRV-infected cells. Additionally, the proper expression of the 90-kDa gIII and 50-kDa gp50 was observed. All three of these PRV-derived glycoproteins were detectable on the surface of vaccinia virus-PRV recombinant-infected cells. In vivo, mice were protected against a virulent PRV challenge after immunization with the PRV glycoprotein-expressing vaccinia virus recombinants. The coexpression of gII and gIII by a single vaccinia virus recombinant resulted in a significantly reduced vaccination dose required to protect mice against PRV challenge. Inoculation of piglets with the various vaccinia virus-PRV glycoprotein recombinants also resulted in protection against virulent PRV challenge as measured by weight gain. The simultaneous expression of gII and gp50 in swine resulted in a significantly enhanced level of protection as evaluated by weight evolution following challenge with live PRV.

Animals↗
PubMed1991

Recombinant vaccinia virus expression of the bovine leukaemia virus envelope gene and protection of immunized sheep against infection.

The bovine leukaemia virus (BLV) envelope gene encoding extracellular glycoprotein gp51 and transmembrane glycoprotein gp30 was cloned into the HA locus of vaccinia virus (Copenhagen strain), downstream of the vaccinia virus early-late promoter, H6, or a triple promoter element consisting of the promoter for the vaccinia virus H6 gene, the promoter for the cowpox virus A-type inclusion (ATI) gene and the promoter for the vaccinia virus HA gene. Inoculation of rabbits or sheep with the recombinant vaccinia virus coding for gp51 and gp30 or an uncleaved env precursor induced neutralizing antibodies to BLV. These antibodies competed with monoclonal antibodies directed against gp51 epitopes F, G, and H previously shown to be of crucial importance for BLV infection. Seven out of eight sheep vaccinated with the vaccinia recombinants resisted a drastic challenge (1.5 x 10(3) sheep infectious doses) with BLV-infected lymphocytes. These results show that vaccination with BLV env vaccinia recombinants protects sheep against infection with extremely high doses of BLV-infected heterologous lymphocytes.

Animals↗