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Biomedical subjects

M Audebert

Publications and source records attributed to M Audebert.

At least 19 recordsLinked to original sources
PubMed2002

[Pulmonary embolism and sibilant types of chronic obstructive pulmonary disease decompensations].

Pulmonary Embolism (PE) poses an important diagnostic problem in patients with chronic obstructive pulmonary disease (COPD). Indeed PE may aggravate the already precarious respiratory state of these fragile patients. Moreover, these two conditions share common symptoms: dyspnoea, wheezing, pleural pain, haemoptysis, palpitations and signs of right cardiac insufficiency. In two studies, one retrospective and the other prospective, we investigated the incidence of PE in patients with non-infective exacerbations of their COPD. The retrospective study was carried out over two years and involved 50 COPD patients with non-infective respiratory exacerbations. In this population, 10 patients out of 50 (20%) had a documented PE. No predictive factor was identified. The prospective study was conducted over one year and COPD patients admitted to hospital with exacerbations were included in the study if they had a positive D-dimer blood test and no evidence of acute respiratory infection. 31 patients were studied with Doppler ultra-sound examination of the legs and a lung perfusion scan. The presence or absence of PE was determined and the two groups were compared. 9 patients out of 31 (29%) had a documented PE. Six of these nine patients had a deep venous thrombosis (DVT). Two predictive factors of PE were identified: existence of a DVT and a significant fall in PaO(2) from baseline state (DeltaPaO(2) > 22 mmHg). We conclude that PE is a frequent (20 to 30%) of non-infective respiratory decompensation in COPD patients. Faced with an unexplained respiratory exacerbation in these patients, a lung perfusion scan should be routinely undertaken to rule out a PE when the D-dimers are positive.

Aged↗
PubMed2000

Alterations of the DNA repair gene OGG1 in human clear cell carcinomas of the kidney.

The OGG1 gene, which codes for a DNA repair protein with antimutator activity, is located on chromosome 3p25, a frequent site of allelic deletions in many types of human tumors, including renal clear cell cancers. We present the analysis of 99 renal tumors for alterations in the OGG1 gene to determine its association with tumorigenesis. Loss of heterozygosity in the 3p25 region was found for 85% of the informative cases. We detected somatic missense mutations of the OGG1 gene in 4 of the 99 tumor samples. Biochemical analysis of the mutant proteins revealed that a substitution at codon 46 impairs the enzymatic activity. We also describe the occurrence of several polymorphisms as well as aberrantly spliced OGG1 transcripts.

Adenocarcinoma, Clear Cell↗
PubMed2000

Effect of single mutations in the OGG1 gene found in human tumors on the substrate specificity of the Ogg1 protein.

We have investigated the effect of single amino acid substitutions of conserved arginines on the catalytic activities of the human Ogg1 protein (alpha-hOgg1-Ser(326)) (wild-type alpha-hOgg1). Mutant forms of hOgg1 with mutations Arg(46)-->Gln (alpha-hOgg1-Gln(46)) and Arg(154)-->His (alpha-hOgg1-His(154)) have previously been identified in human tumors. The mutant proteins alpha-hOgg1-Gln(46) and alpha-hOgg1-His(154) were expressed in Escherichia coli and purified to homogeneity. The substrate specificities of these proteins and wild-type alpha-hOgg1 were investigated using gamma-irradiated DNA and the technique of gas chromatography/isotope-dilution mass spectrometry. All three enzymes excised 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua) and 8-hydroxyguanine (8-OH-Gua) from gamma-irradiated DNA containing a multiplicity of base lesions. Michaelis-Menten kinetics of excision were measured. Significant differences between excision kinetics of these three enzymes were observed. Excision of FapyGua and 8-OH-Gua by wild-type alpha-hOgg1 was greater than that by alpha-hOgg1-Gln(46) and alpha-hOgg1-His(154). The latter mutant protein was less active than the former. The diminished activity of the mutant proteins was more pronounced for 8-OH-Gua than for FapyGua. Cleavage assays were also performed using (32)P-labeled 34mer oligonucleotide duplexes containing a single 8-OH-Gua paired to each of the four DNA bases. The results obtained with the oligonucleotide containing the 8-OH-Gua/Cyt pair were in good agreement with those observed with gamma-irradiated DNA. Wild-type alpha-hOgg1 and its mutants repaired the three mismatches less efficiently than the 8-OH-Gua/Cyt pair. The substitution of Arg(154), in addition to diminishing the activity on 8-OH-Gua, relaxes the selectivity found in the wild-type alpha-hOgg1 for the base opposite 8-OH-Gua. Taken together the results show that the mutant forms alpha-hOgg1-Gln(46) and alpha-hOgg1-His(154) found in human tumors are defective in their catalytic capacities.

DNA↗
PubMed1998

[Value of imaging in early diagnosis of peripheral vein tumors].

Peripheral venous tumors are uncommon and their delayed clinical expression leads to poor prognosis. We report a series of 7 cases including 6 leiomyosacromas and 1 hemangioendothelioma. Duplex Doppler and MR imaging appeared to be best suited for diagnosis, allowing an evaluation of extension and an analysis of associated endoluminal thrombi. These imaging techniques help guide surgery and improve prognosis.

Adolescent↗
PubMed1986

[Biermer's disease and selective IgA deficiency. Apropos of a case].

The authors report a case of pernicious anaemia in a 41-year old white man; this case has particular features: rise in mean corpuscular volume, neurological manifestation 8 and 2 years respectively before diagnosis, association with selective IgA deficiency. Relations between pernicious anaemia and immunoglobulin deficiency are discussed.

Adult↗
PubMed1984

[Gallbladder atony and celiac disease in adults. Radiographic and echographic study of 15 cases].

Gallbladder emptying was evaluated in 15 adult celiac disease patients by oral cholecystography or ultrasonography, after fatty meal or cholecystokinin stimulation. Gallbladder inertia was found in 13 cases. Our study agrees with previously reported results; however it is the first one in which this abnormality was demonstrated by ultrasonography. Our findings may suggest that gallbladder inertia is due to duodenal release of an inactive endogenous cholecystokinin. Control studies demonstrates that gallbladder inertia is reversible after gluten-free diet, recurs with relapse, and thus represents a true celiac disease sign, and not an associated condition. Finally, our cases suggest that gallbladder inertia may be radiologically evident before clinical features of malabsorption become apparent. Awareness of this possibility may persuade the radiologist to research in this condition an occult celiac disease.

Adult↗
PubMed1983

[Choledochocele in adults].

Choledochocele are cystic polypoid lesions of the end portion of the common bile duct. The occurrence of choledochocele is 4 p. cent among choledochal cysts. One case is presented in a 78-year-old woman. The treatment was surgical excision. This case was unusual by the age of the patient and by the diagnosis missed at the time of a cholecystectomy performed one year previously.

Adult↗
PubMed1979

[Complications of digestive involvement in CRST syndrome. 3 cases (author's transl)].

In CRST syndrome, latent oesophageal involvement is common but not usually associated with any clinical manifestations. Involvement of the small intestine is rare. In three patients there occurred severe complications related to digestive involvement in the condition. In one case, involvement of the small intestine was associated with functional obstruction. In the other two patients, oesophageal involvement progressed to very tight stenosis of the lower end of the eosophagus. The generally accepted bening nature of this form of scleroderma must therefore be questioned.

Aged↗