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M Danton

Publications and source records attributed to M Danton.

12 recordsLinked to original sources
PubMed2005

Harderoporphyrin: a misnomer.

More than 30 years ago it was reported that rodent Harderian glands contained a tricarboxylic acid porphyrin, which the authors named Harderoporphyrin. The recent finding in rat Harderian glands of the porphyrin glycoconjugate, protoporphyrin-1-O-acyl-beta-xyloside as a major component led to scrutiny of earlier publications. It became apparent that the results were flawed and that the conclusions were unsustainable. The procedural artefacts which led to the errors are discussed and their bases are demonstrated experimentally. Harderoporphyrin as originally defined never existed.

Animals↗
PubMed2000

Is the secretion of atrial natriuretic peptide in man under neural control?

AIMS: Previous work has described short-term variation in the circulating plasma level of atrial natriuretic peptide (ANP), but the mechanism remains unknown. Our aim was to investigate the role of cardiac innervation in this variability. METHODS AND RESULTS: Blood samples were obtained from the right atrium via a pulmonary artery flotation catheter every 2 min over a 90 min period. Seven patients who underwent cardiac transplantation by the standard biatrial technique (partial innervation) and ten patients who underwent transplantation by the bicaval technique (total denervation) were studied. ANP levels were measured by radioimmunoassay. The median ANP levels were somewhat higher in the biatrial group compared to the bicaval group [470 (150-1095) vs. 216 (100-605) pg. ml(-1); median (range); P = ns], and both were much higher than normal levels in the pulmonary artery (40 (24, 56) pg ml(-1); median and interquartile range). In both transplant groups circulating plasma ANP levels showed considerable variability. The median number of 'peaks' and 'troughs', as counted by visual inspection, were not significantly different between the two groups. Computer analysis identified 12-16 and 6-15 'pulses' in the biatrial and bicaval group, respectively. Further analysis revealed that pulse amplitude, height and area were significantly higher in the biatrial compared to the bicaval group. CONCLUSION: It would appear that variability of circulating plasma levels of ANP is preserved despite complete or partial cardiac denervation, and so a neural mechanism does not appear to account for such variation.

Adult↗
PubMed2000

Narrowing of the region of allelic loss in 21q11-21 in squamous non-small cell lung carcinoma and cloning of a novel ubiquitin-specific protease gene from the deleted segment.

We examined 42 fresh non-small cell lung carcinomas for allelic loss using 4 microsatellite markers located in a 4.5 Mb region in 21q11-21, a gene-poor interval recently found by others to be homozygously deleted and exhibiting frequent allelic loss in lung cancer. We found allelic loss across the entire segment in 13/34 informative squamous carcinomas, with 2 cases showing loss in only part of the region. Analysis by fluorescence in situ hybridization of P1-derived artificial chromosomes from the region directly on paraffin sections of the tumor is in concordance with the loss of heterozygosity (LOH) results, and tentatively excludes a 2 Mb segment bearing 2 of the only 3 known genes in the area. Exon trapping in the remaining segment of loss led to identification and cloning of a novel gene spanning 150 kb within the deletion. The full-length gene encodes a protein of 1,055 amino acids with homology to ubiquitin-specific proteases across the eukaryotic evolutionary spectrum. The expressed protein acts as a de-ubiquitinating enzyme as proved by the ability to cleave ubiquitin from a model fusion protein. We found no mutations in the sequence of the functional domains of this gene in any of the LOH-exhibiting tumor DNA samples. It is, however, interesting that genes of the same superfamily have been reported on 3p21, a locus showing the most frequent allelic instability and deletions in lung cancer. Genes Chromosomes Cancer 27:153-161, 2000.

Amino Acid Sequence↗
PubMed1995

[Epidemiology of infectious hematopoietic necrosis (IHN) of salmonid fish in France: study of the course of natural infection by combined use of viral and seroneutralization test and eradication attempts].

Infectious haematopoietic necrosis (IHN), a rhabdoviral infection of salmonid fish, was considered to be an exotic disease in Europe until it was recognized in France and Italy in 1987. In France, the existence of this new condition led the authorities in charge of animal health to order epidemiological studies to be undertaken. These studies were based upon virological, serological and experimental diagnostic methods and also encompassed disease eradication attempts. Studies were conducted at 7 fish farming sites, involved 1,545 salmonid fish, of which 848 were sacrificed, and represented 262 virological examinations and 1,782 serum neutralization tests. The presence of the IHN virus was detected in the 7 trout farm fish populations that were located in 5 regions, one of which was situated 600 km from the place where the first isolation of IHN virus was made. Moreover, 6 out of 7 rainbow trout populations reared in these farms also harboured viral haemorrhagic septicaemia virus (VHSV) often resulting in overt disease. Rainbow trout was the only salmonid fish species found infected with IHN. Overt infection, which was observed in fish ageing less than 2,200 degrees-days, always occurred at water temperatures below 14 degrees C, and the younger fish were more susceptible (mortality rate > or = 80%). Although the IHN virus is easily isolable from fish undergoing overt infection, it was hardly detectable in survivors until they were adults, at which stage the virus was shedded via sexual products which constituted suitable materials for virological examination and disease transmission assays. Survivors of overt and dormant IHN infection developed consistent immune response and special attention was paid to neutralizing antibodies (NAb) to IHN virus. The detection of such NAb in fish from infected farming sites or other NAb from presumably IHN-free sites, correlated fairly well with the presence and further detection of IHN virus among such fish populations. Our data provide arguments for considering the serological technique as a suitable means of completing fish health surveillance programmes for IHN. Although our results are in agreement with part of the existing knowledge on IHN, they differed in several points: rainbow trout was the only susceptible fish species; overt IHN was always recorded in juveniles and at water temperatures below 14 degrees C; IHN virus could not be recovered from the mucus of infected broodfish; IHN infection usually coexisted with VHS infection in same fish population; and serology was widely and successfully used for the diagnosis of IHN.

Animals↗
PubMed1995

Serum neutralization test for epidemiological studies of salmonid rhabdoviroses in France.

Serological examination is not yet accepted as being a suitable diagnostic method for fish that are asymptomatic virus carriers. Nevertheless, encouraging preliminary results using an end-point serum neutralization test (SNT) in several French trout farm populations have demonstrated an excellent correlation between the SNT and the previously established virus histories of the tested populations. Following the isolation of infectious haematopoietic necrosis virus (IHNV) in France, serological screening of fish for a neutralizing antibody (NAb) to IHN was conducted on a national scale. This survey confirmed the relationship between the serum-neutralizing immune response of the fish and the presence of IHNV in a given trout farm population. Insofar as many trout populations underwent dual rhabdovirus infections with both IHNV and viral haemorrhagic septicemia virus (VHSV), NAbs to both viruses were also detected in the fish from such populations, often in distinct individuals. NAb-responding fish became detectable 2-3 months post-infection (pi). The number of responding fish reached a mean prevalence of 20% between 3 and 6 months pi and disappeared after 8 months. The neutralizing serum titres (NST) were considered positive at > or = 32 and 64 for VHSV and IHNV, respectively. Both the NST results and the prevalence varied greatly according to individuals, populations and the number of repeated stimuli involved in a given serum sampling series. Conversely, the thousands of sera collected from trout in virus-free farms did not display any neutralizing activity against either VHSV or IHNV.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed1995

Conformational studies of the beta-subunit of the high affinity IgE receptor: circular dichroism and molecular modelling.

The receptor with high affinity for immunoglobulin E (Fc epsilon RI) on mast cells and basophils plays an important role in mediating many of the pathophysiological phenomena associated with allergy. Fc epsilon RI is a tetrameric complex, alpha beta gamma2, of non-covalently attached subunits: one IgE-binding alpha-subunit with the binding site in the extracellular part of the chain, one beta-subunit and a dimer of disulphide linked gamma-subunits. In the present work, prediction of the three-dimensional structure of the four membrane-spanning segments of the beta-subunit has been achieved using rules of helix-helix packing arrangements and molecular dynamics calculations. It yielded a four-helix bundle with specific Van der Waals interactions between the helices. This four-helix bundle was used as a framework upon which to calculate the conformation of the beta-subunit excluding the C and N terminal cytoplasmic tails, but including the three chains that connect the four helices in the bundle. Separately, these synthetic 11, 17 and 29 residue bridge peptides were examined by circular dichroism (CD) spectroscopy and a degree of alpha-helical content in these bridge peptides was found. Additional molecular modelling of the bridge peptides indicate the central residues of these as the location of the helical moieties. Finally, in the model proposed for the beta-subunit, for each pair of consecutive transmembrane (TM) helices and its bridge peptide, a helix-loop-helix-loop-helix motif was found.

Amino Acid Sequence↗
PubMed1992

Prophylactic digitalisation in pulmonary surgery.

BACKGROUND: Prophylactic digoxin is widely used in patients undergoing pulmonary surgery to prevent or control cardiac arrhythmias, but whether it is helpful or not is uncertain. METHODS: An open, controlled randomised prospective clinical study of 111 patients was undertaken to compare the incidence of cardiac arrhythmias in the 58 patients who received preoperative digoxin and the 53 who did not. RESULTS: Cardiac arrhythmia occurred in half (29/58) of those given prophylactic digoxin and in 36% (19/53) of those who were not. The overall incidence of arrhythmia was 43%, with no statistically significant difference between the groups. CONCLUSION: Cardiac arrhythmias remain an important complication of pulmonary surgery and the incidence is not reduced by prophylactic digoxin.

Aged↗
PubMed1980

[SVCV infection of Carp (author's transl)].

This word was carried out to confirm several pathogenical points which had been previously outlined during SVCV infection trials of carp performed in autumn at + 11 degrees C, when the temperature was naturally decreased. Here, 50 g carp which had undergone the wintering, were infected in spring either via the water-route (2 h in 5 x 10(3) pfu/ml water) or intraperitoneally (5 x 10(3) pfu/fish) when the natural elevation of the water temperature had reached + 11 degrees C. Then the fish appeared to be readily susceptible to infection and the course of the disease estimated by the virus detection in gill, blood and water, was 3 to 4 times quicker than that of the autumn infection. The virus detection in gill is the first clue of contamination and the viraemia accounts for the spleen and kidney target cells infection and its increase is fatal.

Animals↗