Biomedical subjects

C Gaillard

Publications and source records attributed to C Gaillard.

At least 91 records · Page 5Linked to original sources

PubMed1995

Dipeptide transport in barley mesophyll vacuoles.

The transport of [14C]glycyl-glycine (Gly-Gly) across the tonoplast of isolated barley vacuoles has been characterized. Uptake of the dipeptide Gly-Gly into barley mesophyll vacuoles was strongly increased by the addition of ATP, while Mg2+ inhibited the ATP-dependent fluxes. Inhibition of the vacuolar proton pump by bafilomycin or dissipation of the delta pH had no effect on the ATP-dependent Gly-Gly uptake. Only the non-hydrolysable ATP analogue 5'-adenylylimidodiphosphate could partially substitute for ATP; ADP, GTP and UTP had no effect. Transport of Gly-Gly was saturable exhibiting an apparent Km of 49 +/- 5 mM. Uptake was inhibited by the sulphydryl reagents N-ethylmaleimide and p-chloromercuribenzenesulphonic acid. When present at 30 mM, various dipeptides as well as tri-glycine inhibited Gly-Gly (10 mM) uptake by 30-50%, whereas 5 mM phenylalanine was able to inhibit Gly-Gly uptake almost completely. Comparison with published data suggests that Gly-Gly is transferred across the tonoplast by the same system as several amino acids and inorganic ions.

Adenosine Triphosphate↗

PubMed1995

Microsatellite-based parentage control in cattle.

As a new approach to parentage control we developed two multiplex coamplification polymerase chain reaction (PCR) systems containing a total of six different short tandem repeat (STR) loci; the microsatellite polymorphisms were visualized by automated fluorescence detection on the Applied Biosystems 373 DNA Sequencer with 672 Genescan Analysis software. Allele frequency data were determined from 238 animals. Thirty-five bovine parentage control cases not solvable by conventional blood typing could be solved.

Alleles↗

PubMed1995

Features of the DNA fingerprinting probe pITZ1.

Stringently controlled plasmids generate DNA fingerprint patterns in mammals when used at low hybridization temperatures. In order to develop a probe for use in paternity testing in cattle we screened a bovine, partial genomic plasmid library with the PCR-amplified ori region of plasmid P1. Of eight isolated clones one generated strong band patterns at high stringency in various mammalian species (data not shown). Sequence analysis revealed an imperfect, compound dinucleotide repeat region, which was PCR-amplified and cloned into the plasmid vector pUC19. Fingerprint results generated by this probe (termed pITZ1) in cattle are compared with the results generated by VNTR-probe pV47, which itself was developed by screening a human chromosome 16 library with tandem repeats of bacteriophage M13. Probe pITZ1 is useful in conjunction with other VNTR-probes for DNA fingerprinting in cattle and donkey populations. The dinucleotide repeat region responsible for the band patterns generated with pITZ1 is close to an Alu-like sequence, which may be involved in eukaryotic replication mechanisms.

Animals↗

PubMed1995

Use of an oral antiseptic bioadhesive tablet in dogs.

V3703 (Stomadhex) is a tablet with bioadhesive properties enabling it to remain in place for several hours after it has been placed on the oral mucosa. It continuously releases chlorhexidine and niacinamide. In a study conducted in 15 dogs, the tablets were well tolerated by the animals. The product significantly reduced (p < 0.05): dental plaque; quantitative periodontopathogen and total anaerobic bacterial counts; spirochetes; and halitosis when used daily over a 14 day period. Gingivitis was also reduced, though not significantly (p = 0.07). Stomadhex treatment can provide a carry-over effect following dental scaling by reducing oral microflora and retarding the reappearance of dental plaque.

Administration, Topical↗

PubMed1994

Identity of the RNA-binding protein K of hnRNP particles with protein H16, a sequence-specific single strand DNA-binding protein.

Protein H16, which we have identified previously in mammalian cell lines, binds in vitro to two single stranded DNA sites on the late strand of the early promoter of SV40. It has no other single strand binding site in the SV40 genome and does not bind to double stranded DNA. In vitro, H16 can be shown to stimulate strongly the activity of purified RNA polymerase II. Here we have purified this 70 kDa protein from cultured monkey cells and have sequenced three of its tryptic peptides. The analysis indicates that H16 is the simian homolog of human protein K, a nuclear RNA-binding protein found in heterogeneous nuclear ribonucleoprotein (hnRNP) particles, which contains a KH domain present in several proteins including the fragile X mental retardation gene product (FMR1). The binding affinities of protein K/H16 for RNA and DNA were subsequently compared in detail. They showed that under conditions where K/H16 binds strongly to its single stranded DNA site, it binds very weakly to the corresponding RNA sequence. This result suggests a possible shuttling of the protein from RNA to DNA during processes which involve opening of the DNA double helix.

Amino Acid Sequence↗

PubMed1994

A herbicide antidote (safener) induces the activity of both the herbicide detoxifying enzyme and of a vacuolar transporter for the detoxified herbicide.

In plants potentially toxic compounds are ultimately deposited in the large central vacuole. In this report we show that isolated barley mesophyll vacuoles take up the glucoside conjugate of the herbicide derivate [5-hydroxyphenyl]primisulfuron. Transport is stimulated by Mg-ATP and is distinct from that previously described for glutathione conjugates. Treatment of barley with different herbicide antidotes (safeners) revealed that the safener cloquintocet-mexyl doubles the vacuolar transport activities for both the glutathione and glucoside conjugates. Stimulation of the uptake of the metolachlor-glutathione conjugate was the result of an increased uptake velocity whereas the Km remained unaltered, suggesting that the higher activity was due to a higher expression of the transporter. These results indicate that modulation of vacuolar transport activities are an integral part of the detoxification mechanism of plants.

Acetamides↗

PubMed1994

Association of poly(CA).poly(TG) DNA fragments into four-stranded complexes bound by HMG1 and 2.

The tandemly repeated DNA sequence poly(CA).poly(TG) is found in tracts up to 60 base pairs long, dispersed at thousands of sites throughout the genomes of eukaryotes. Double-stranded DNA fragments containing such sequences associated spontaneously with each other in vitro, in the absence of protein, forming stable four-stranded structures that were detected by gel electrophoresis and electron microscopy. These structures were recognized specifically by the nuclear nonhistone high mobility group (HMG) proteins 1 and 2 as evidenced by gel retardation. Such sequence-specific complexes might be involved in vivo in recombination or other processes requiring specific association of two double-stranded DNA molecules.

Base Sequence↗

PubMed1994

Role of CD40 antigen and interleukin-2 in T cell-dependent human B lymphocyte growth.

In the present study, we examined the participation of CD40 ligand (L)-CD40 interaction in T cell-dependent B cell responses. To this end, purified B lymphocytes were cultured over irradiated CD4+ cloned T cells activated with immobilized anti-CD3 antibody. The anti-CD40 mAb 89 strongly blocked, in a specific fashion, both proliferation and Ig secretion of tonsil B cells. Interestingly, proliferation of surface (s)IgD+ B cell was significantly less inhibited by anti-CD40 than that of sIgD- cells. Preactivated T cells induced B cells to grow and secrete immunoglobulins preferentially in response to IL-2. This contrasts with the CD40 system where B cells are essentially responsive to IL-4 and IL-10 but not to IL-2 alone. Collectively, these data indicate that CD40L-CD40 interaction plays an important role in IL-2 mediated T cell-dependent B cell responses. However, the activation of a subset of sIgD+ cells may be independent of this interaction.

Antigens, CD↗

PubMed1994

B cells regulate expression of CD40 ligand on activated T cells by lowering the mRNA level and through the release of soluble CD40.

The expression of CD40 ligand (CD40L) on activated T cells (CD4+ T cell clone MT9) is diminished when the T cells are cultured in the presence of B cells. This effect, observed both with normal tonsil B cells and with the B cell line JY, was detected after 6 h and sustained at least until 18 h of co-culture. Analysis of mRNA showed that CD40L mRNA levels were not modified after 6 h, but were significantly down-regulated after 18 h of co-culture with B cells. Although CD40L expression could not be detected by a CD40-Fc chimera, the molecule was still expressed at the membrane as shown with a polyclonal antiserum against CD40L (anti-TRAP). In addition, T cells activated in the presence of B cells were stained by a polyclonal antiserum against CD40, without the appearance of CD40 mRNA. These results indicated that a soluble form of CD40 (sCD40) bound to the expressed CD40L on T cells. The existence of sCD40 was confirmed by detection of sCD40 in B cell supernatants using a specific enzyme-linked immunosorbent assay. Collectively, these data show that B cells can regulate the expression of CD40L on activated T cells at least by two different mechanisms.

Antigens, CD↗

PubMed1994

In vitro antibacterial activity of sucralfate.

The effect of sucralfate (12.5 mg/ml) on the growth of Escherichia coli (ATCC 25922), Enterococcus faecalis (ATCC 29212) and two isolates of Pseudomonas aeruginosa (ATCC 27853 and a multi-resistant clinical isolate) was studied in vitro at pH values of 3.0, 4.5, 6.0 and 7.4. A bacteriostatic effect of sucralfate was demonstrated for Pseudomonas aeruginosa at a pH of 6.0 and 7.4 and for Escherichia coli and Enterococcus faecalis at a pH of 6.0. The bacteriostatic effect was most pronounced at high pH values. Sucralfate had no bactericidal effect on the bacteria tested at the concentration used.

Bacteria↗

PubMed1994

Repetitive plasmid sequences generate DNA fingerprinting patterns in mammals.

Bacterial plasmids with stringently regulated copy numbers have directly repeated DNA sequences, termed iterons, in the vicinity of their replication origins. These sequences bind a specific protein exerting a key role in the initiation of plasmid replication. Plasmids P1, pSC101 and RFS1010 have different iteron sequences and belong to three different incompatibility groups. Used as DNA probes each of these plasmids generates specific patterns in mammals similar to those obtained by the DNA fingerprinting technique. The iteron-containing regions were identified as the part of the plasmids responsible for those patterns by using polymerase chain reaction (PCR) amplified DNA segments that contained the iteron regions as probes.

Animals↗

PubMed1994

Studies on the frequency and associations of equine leucocyte antigens in sarcoid and summer dermatitis.

The equine leucocyte antigen (ELA) types and the clinical diagnosis for equine sarcoid and summer dermatitis were evaluated in 2026 horses representing five breeds. Data were analysed in unrelated animals and in family material. In the case of equine sarcoid, a strong association was observed between the ELA class II DW13 antigen and its effect on Swiss (cP < 0.001), French (cP < 0.0001) and Irish (cP < 0.01) Warmblood horses. The class I antigen A3 occurred more frequently in sarcoid-affected French horses (cP < 0.001). These results confirm our earlier findings (Gerber et al. 1988). Among Freiberger horses, which lack the ELA DW13 and A3 specificities, a breed-specific class I antigen, ABe108, displayed an increased frequency (cP < 0.05) in the affected group. Among Arabian horses, a tendency for increased frequency of the A1 antigen was observed in the affected animals, but the number of affected horses is too small for statistical significance. The Mendelian segregation in diseased half-siblings by ELA DW13 heterozygous stallions showed a strong association (P < 0.0001) between the inherited DW13 antigen and susceptibility to the sarcoid effect. In the case of summer dermatitis, previously published data (Marti et al. 1992) have been extended. The ELA types in four multiple-case families, founded by the same stallion, were analysed for an association with the effect of sarcoid. Eight out of nine ELA-typed affected offspring inherited the paternal haplotype A15, DW23 in contrast to nonaffected offspring where three out of 12 displayed these antigens (P < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗

PubMed1994

[Genetic basis of idiopathic epilepsy in the golden retriever].

The genetic aspect of idiopathic epilepsy in the Golden Retriever was examined. 336 pedigrees of a population of normal and epileptic dogs from five different generations were statistically evaluated. Most patients showed generalized Grand-mal seizures and the onset was within one to three years in 75% of the dogs. A significant sex predisposition for males was found. The increased manifestation of seizures in some subpopulations and the repeated occurrence in different families of the same sires revealed that there is a genetic basis for the condition of this breed. The results of pedigree analyses and binomial test support the hypothesis of an autosomal multifactorial recessive mode of inheritance. However, only an objective test-mating programme is likely to delineate the exact mode of inheritance.

Age Factors↗

PubMed1993

Enzyme immunoassay using a rat prolactin-alkaline phosphatase recombinant tracer.

This paper describes a competitive enzyme immunoassay of rat prolactin (rPrl) using a recombinant conjugate as a colorimetric tracer. rPrl was inserted into the N-terminal end of Escherichia coli alkaline phosphatase (AP), using an expression vector which allows insertion of foreign DNA sequences between codons +6 and +7 of the phoA gene. The assay was performed in 96-well microtiter plates coated with a mouse monoclonal antibody raised against rabbit immunoglobulin G. Each component (recombinant tracer, rabbit antiserum against rPrl, and rPrl standard) was added in a volume of 50 microL. The sensitivity of the assay was sufficiently high to allow titration of rPrl in plasma. The detection threshold was 15 pg (0.3 ng/mL) and the B/B0 50% value was 150 pg (3 ng/mL). The intraassay coefficient of variation was less than 10% over a wide range of rPrl concentrations (2.9-50 ng/mL). The interassay coefficient of variation was less than 15% for rat plasma samples in the concentration range of 4-40 ng/mL. The good parallelism observed between the standard curve and sample dilution curves showed that the immunoreactivity in rat plasma behaves like standard rPrl. Together with recovery experiments, these results indicated that assay without extraction is possible. A single immunoreactive peak that comigrates with standard rPrl is observed after molecular sieve fractionation of plasma samples. The reliability of the assay was confirmed by good correlation with conventional radioimmunoassay (r = 0.996, slope 0.978).

Alkaline Phosphatase↗

PubMed1993

Expression of a 32-kDa ligand for the CD40 antigen on activated human T lymphocytes.

To identify the ligand(s) of the human CD40 antigen, a cDNA encoding the extracellular domain of the CD40 antigen was fused to a cDNA encoding the constant region (Fc) of human IgG1. The CD40-Fc fusion protein was able to specifically bind to CD4+ and various CD8+ T cell clones activated with immobilized anti-CD3. The 125I-labeled CD40-Fc fusion protein bound anti-CD3 activated CD4+ T cell clone (MT9) with an equilibrium dissociation constant (Kd) of 10-20 nM. The human CD40-binding protein expressed on the cell surface of activated T lymphocytes is a monomeric protein of approximately 32 kDa. Minor components of 29 kDa and 17 kDa were also detected. A small proportion of CD4+ and CD8+ blood mononuclear T cells activated by anti-CD3 expressed the CD40 ligand but its detection was best observed following depletion of B cells. Addition of B cells to purified T cells abolished the binding of CD40-Fc obtained after anti-CD3 activation.

Antigens, CD↗

PubMed1993

Quantitative traits in chicken associated with DNA fingerprint bands.

In an unselected control line of a selection experiment in chicken the following traits were evaluated: number of eggs, average egg weight, egg mass, age at first egg, body weight at 20 weeks, body weight at 40 weeks, feed consumption and feed efficiency (feed consumption/egg mass). Data and blood samples of 143 females of the same age were available for analysis. The animals were ranked for each trait according to the phenotypic performance adjusted for hatch and laying house effect rather than the breeding value. DNA mixes of the top 5 and the bottom 5 hens were compared to each other by DNA fingerprinting. The most striking differences could be observed with the probe pV47 in the mixes for body weight at 20 weeks and the feed efficiency. In the following the study focused on feed efficiency. Five groups of 10 hens each, around quantiles 0%, 25%, 50%, 75% and 100%, were analyzed with respect to the occurrence of 7 particular DNA fingerprint bands. The association of the groups' mean feed efficiency with the groups' band frequencies was assessed by linear regression. For 2 bands significant regression coefficients (P < 0.005) were found.

Alleles↗

PubMed1993

Effect of cutting on solute uptake by plasma membrane vesicles from sugar beet (Beta vulgaris L.) leaves.

The uptake of sucrose, 3-O-methylglucose (3-O-MeG), and valine were studied in discs and in purified plasma membrane vesicles (PMV) prepared from sugar beet (Beta vulgaris L.) exporting leaves. The uptake capacities of freshly excised leaf discs were compared with the uptake in discs that had been floated for 12 h on a simple medium (aging) and with discs excised from leaves that had been cut from the plant 12 h before the experiments (cutting). After cutting, sucrose uptake amounted to twice the uptake measured in fresh discs, whereas the uptake of 3-O-MeG and valine remained unaffected. In aged leaf discs, there was a general stimulation of uptake, which represented 400, 300, and 400% of the uptake measured in fresh discs for sucrose, 3-O-MeG, and valine, respectively. Sucrose uptake in fresh discs was sensitive to N-ethylmaleimide (NEM), to p-chloromercuribenzenesulfonic acid (PCMBS), and to mersalyl acid (MA). Although cutting induced the appearance of a sucrose uptake system that is poorly sensitive to NEM but sensitive to PCMBS and MA, aging induced the development of an uptake system that is sensitive to NEM but poorly sensitive to PCMBS and MA. Autoradiographs of discs fed with [14C]sucrose show that cutting resulted in an increase of vein labeling with little effect in the mesophyll, whereas aging induced an increase of labeling located mainly in the mesophyll. The data show that cutting is sufficient to induce dramatic and selective changes in the uptake properties of leaf tissues and that the effects of cutting and aging on the uptake of organic solutes are clearly different. Parallel experiments were run with purified PMV prepared from fresh and cut leaves. The uptake of sugars and amino acids was studied after imposition of an artificial proton motive force (pmf). Comparison of the uptake properties of PMV and of leaf tissues indicate that the recovery of the sucrose uptake system in PMV is better than the recovery of the hexose and of the valine uptake systems. As observed with the leaf discs, cutting induced a 2-fold increase of the initial rate of sucrose uptake in PMV but did not affect the uptake of valine and 3-O-MeG. Cutting induced an increase of both Vmax and Km of the sucrose transport system in PMV. Measurements of the pmf imposed on the vesicles indicated that the increase of sucrose uptake induced by cutting was not due to a better integrity of the vesicles. Hexoses did not compete with sucrose for uptake in PMV from fresh and cut leaves, and maltose was a stronger inhibitor of sucrose uptake in PMV from cut leaves than in PMV from fresh leaves. The sensitivity of sucrose uptake to NEM, PCMBS, and MA in PMV from fresh and cut leaves paralleled that described above for the corresponding leaf discs. These data show that (a) the changes induced by cutting on sucrose uptake by leaf discs are due to membrane phenomena and not to the metabolism of sucrose; (b) the study of sucrose uptake with PMB gives a good account of the physiological situation; and (c) the specific effects induced by cutting on the sucrose uptake system are not lost during the preparation of the PMV.

3-O-Methylglucose↗

PubMed1992

The immune response to p53 in breast cancer patients is directed against immunodominant epitopes unrelated to the mutational hot spot.

Alteration of the p53 gene is the most frequent genetic feature of human cancer and leads to overexpression of the altered protein in the tumor cell nucleus. Two diagnostic procedures are currently available to assess p53 mutations: (a) molecular analysis of the gene sequence; and (b) immunohistochemical analysis of p53 protein accumulation. We now report a third approach, serological analysis. Fifteen % of primary breast cancer patients were found to have circulating antibodies to p53 protein by immunoprecipitation or immunoblotting. We have found a close correlation between the presence of such antibodies and bad prognosis such as high histological grade and the absence of hormone receptors. Furthermore, we found that the B-cell response to p53 protein is induced by two immunodominant regions located at the carboxy and amino termini of the protein, outside the central mutational hot spot region. These findings suggest that serological analysis, combined with molecular and histochemical methods, may be suitable for assessing the state of the p53 gene in cancer patients.

Antibodies, Neoplasm↗