Biomedical subjects

F Mathieu

Publications and source records attributed to F Mathieu.

At least 19 recordsLinked to original sources

PubMed2006

Lack of influence of COMT and NET genes variants on executive functions in schizophrenic and bipolar patients, their first-degree relatives and controls.

Abnormal dopaminergic function in the prefrontal cortex (PFC) may be a key factor in the etiopathogeny of schizophrenia and bipolar disorder. Both schizophrenic and bipolar subjects have executive functions (EF) deficits, thought to reflect abnormal PFC function. The main inactivation pathways for dopamine in the PFC are enzymatic cleavage by the Carboxy-O-Methyl-Transferase (COMT) and reuptake by the nor-epinephrine transporter (NET). Our aim in this study was to replicate previous studies that investigated influence of the COMT genotype on EF in schizophrenic subjects, their relatives and controls and extend their scope by including bipolar patients, and their relatives and by exploring NET gene polymorphisms influence on executive performances. We investigated one functional polymorphism of the COMT gene and two polymorphisms of the NET gene. EF were assessed by means of the Trail Making Test (TMT) and the Wisconsin Card Sorting Test (WCST). We assessed the effect of each of the three genotypes on EF for the whole sample (N = 318) and separately in schizophrenic (N = 66), bipolar (N = 94) and healthy subjects (i.e., relatives and controls N = 158). Separate analyses were performed because of the presence, in patients samples, of potentially confounding factors, especially medication. Genotype had no significant effect on the cognitive measures in any of the analyses (for the two EF measures, the three polymorphisms, and the four groups). In our sample we found no evidence in favor of a major effect of COMT or NET polymorphisms on the two tests of EF.

Adult↗

PubMed2006

Black aspergilli and ochratoxin A production in French vineyards.

A survey on the occurrence on grape of black Aspergillus species and their capability to produce ochratoxin A (OTA) was conducted in France over three years (2001-2003) in 10 vineyards from four winemaking regions with different geographical locations and climatic conditions. During 2001 and 2002, from setting to harvest, the total numbers of fungal isolates were respectively 721 and 711 increasing in 2003 to reach 1035. The Aspergillus genus was essentially represented by Section Nigri (99%) and it was predominant (80%+/-4.6) when compared to Penicillium (20%+/-4.6). Regardless of sampling year, 32.5% (+/-sigma=1.26) of the fungal isolates were OTA producers and 93% (+/-sigma=2.65) belonging to black aspergilli. The ochratoxigenic potential of the isolates and their occurrence on grapes revealed that Aspergillus carbonarius was the main OTA producer (up to 37.5 mug/g). At harvest time, the fungal population was maximal and this was the most critical period influencing OTA contamination. Grapes from Languedoc-Roussillon region were most infested with ochratoxigenic fungi and had the highest concentrations of OTA (up to 2.8 ng/g).

Aspergillus niger↗

PubMed2006

Genome-wide scan for genes involved in bipolar affective disorder in 70 European families ascertained through a bipolar type I early-onset proband: supportive evidence for linkage at 3p14.

Preliminary studies suggested that age at onset (AAO) may help to define homogeneous bipolar affective disorder (BPAD) subtypes. This candidate symptom approach might be useful to identify vulnerability genes. Thus, the probability of detecting major disease-causing genes might be increased by focusing on families with early-onset BPAD type I probands. This study was conducted as part of the European Collaborative Study of Early Onset BPAD (France, Germany, Ireland, Scotland, Switzerland, England, Slovenia). We performed a genome-wide search with 384 microsatellite markers using non-parametric linkage analysis in 87 sib-pairs ascertained through an early-onset BPAD type I proband (AAO of 21 years or below). Non-parametric multipoint analysis suggested eight regions of linkage with P-values<0.01 (2p21, 2q14.3, 3p14, 5q33, 7q36, 10q23, 16q23 and 20p12). The 3p14 region showed the most significant linkage (genome-wide P-value estimated over 10 000 simulated replicates of 0.015 [0.01-0.02]). After genome-wide search analysis, we performed additional linkage analyses with increased marker density using markers in four regions suggestive for linkage and having an information contents lower than 75% (3p14, 10q23, 16q23 and 20p12). For these regions, the information content improved by about 10%. In chromosome 3, the non-parametric linkage score increased from 3.51 to 3.83. This study is the first to use early-onset bipolar type I probands in an attempt to increase sample homogeneity. These preliminary findings require confirmation in independent panels of families.

Adolescent↗

PubMed2006

Effect of the frequency of the mixing of coffee cherries put out for drying on the kinetics of drying and the relationship to ochratoxin A production.

The effect of the frequency of the mixing of coffee cherries put out for sun drying on the kinetics of the drying, fungal growth and kinetics of ochratoxin A production was evaluated. The results showed that the more coffee cherries were mixed, the quicker they dried. This rapidity of drying led to a reduction of fungal development. Indeed, coffee cherries mixed eight and ten times a day, dried quickly and were free inside of fungi. However, infection by fungi gives little indication of ochratoxin A production in coffee cherries. Indeed, although coffee cherries mixed twice a day were more contaminated by fungi, the analysis of ochratoxin A content showed they were free of this mycotoxin. The coffee cherries that were more contaminated by ochratoxin A were those mixed four times a day (containing 0.35-5.46 microg kg(-1) ochratoxin A). Ochratoxin A contamination was essentially due to the presence of Aspergillus species capable of producing ochratoxin A inside the coffee cherries.

Aspergillus↗

PubMed2006

Effect of amino acids containing sulfur on dithiolopyrrolone antibiotic productions by Saccharothrix algeriensis NRRL B-24137.

AIMS: To study the effect of sulfur-containing amino acids (L-cysteine, L-cystine, L-methionine and DL-ethionine) on the production of dithiolopyrrolone antibiotics by Saccharothrix algeriensis NRRL B-24137. METHODS AND RESULTS: The production levels of dithiolopyrrolones were investigated by using high performance liquid chromatography in a chemically semi-synthetic medium. The production of the studied antibiotics depends upon the nature, concentration and the time of addition of these sources in the culture medium. Both cysteine and cystine favoured the specific productions of dithiolopyrrolones; iso-butyryl-pyrrothine (ISP) by cysteine, however butanoyl-pyrrothine, senecioyl-pyrrothine and tigloyl-pyrrothine by cystine, when added initially to the culture medium. The maximum specific productions of dithiolopyrrolones were observed in the presence of 5 mmol l(-1) cystine for thiolutin, 5 mmol l(-1) cysteine for ISP, and 10 mmol l(-1) cystine for others studied dithiolopyrrolones as shown in Fig. 3. The production of these antibiotics was decreased when the concentrations of cysteine and cystine were in excess. All dithiolopyrrolone specific productions were strongly inhibited by addition of methionine and ethionine, without inhibition of mycelial growth. CONCLUSIONS: Among all studied amino acids, cystine and cysteine can be used as supplements for improvement the production of dithiolopyrrolone antibiotics by S. algeriensis NRRL B-24137. SIGNIFICANCE AND IMPACT OF THE STUDY: Dithiolopyrrolone antibiotics have many important applications for employing them as medicaments, particularly in the treatment of human and animal cancers. In the present work, the influence of containing-sulfur amino acids on dithiolopyrrolone antibiotic productions was studied. The obtained results can be employed for the optimization of the culture medium for the dithiolopyrrolone productions in higher quantities.

Actinomycetales↗

PubMed2006

Antimicrobial compounds produced by Actinomadura sp. AC104 isolated from an Algerian Saharan soil.

During a search for nonpolyenic antifungal antibiotics, an actinomycete designated AC104 was isolated from a Saharan soil sample by a dilution agar plating method using a chitin - vitamins B medium supplemented with rifampicin. Isolate AC104 presented the morphological and the chemical characteristics of the genus Actinomadura. On the basis of 76 physiological tests and 16S rDNA analysis, this isolate was determined to be quite different from the known species of Actinomadura. It is active against filamentous fungi and both Gram-positive and Gram-negative bacteria. The production of antibiotic substances was investigated using several culture media. The highest antimicrobial activities were obtained on ISP2 medium. The benzenic extract contained five bioactive spots detected on thin layer chromatography plates. Among these antibiotics, a complex called 104A, which showed the more interesting antifungal activity, was selected and purified by reverse-phase high-pressure liquid chromatography. This complex is composed of four compounds. Ultraviolet-visible, infrared, mass, and 1H nuclear magnetic resonance spectroscopy studies showed that these molecules contain an aromatic ring substituted by aliphatic chains. These compounds differ from the known antibiotics produced by Actinomadura species.

Actinomycetales↗

PubMed2005

Conidia of black aspergilli as new biological adsorbents for ochratoxin A in grape juices and musts.

Biological removal of ochratoxin A (OTA) by living and heat-treated dead conidia of black Aspergillus isolates representing the species Aspergillus niger, Aspergillus carbonarius, and Aspergillus japonicus in synthetic and natural grape juices was found to be a two-stage phenomenon. Several lines of evidence suggest that the first observed stage was passive, metabolism was not required, and OTA adsorption on conidia of black aspergilli could be involved. This removal was fast, without delay just after conidial inoculation both in synthetic and natural grape juices. Moreover, even nonviable, heat-treated conidia were capable of removing OTA. Finally, no OTA degradation products were detected. In the second observed stage, removal of OTA was linked to degradation by live conidia only. Ochratoxin alpha, a degradation product of OTA, was detected in the medium after incubation for 30 and 14 h for biseriate (A. niger and A. carbonarius) and uniseriate (A. japonicus) black aspergilli, respectively, when well-developed mycelium appeared. Comparisons between the three black Aspergillus isolates tested showed that A. carbonarius detoxified grape juice most effectively. However, this species often produces OTA. A. niger and A. japonicus isolates were also effective and because those species are not systematically OTA producers, they could be interesting for further OTA detoxification processes in grape juices and musts.

Adsorption↗

PubMed2005

[Acute cardiomyopathy and severe hypocalcaemia].

Severe electrolyte imbalance is rarely the cause of cardiac decompensation. We report the case of a young patient with acute left ventricular failure due to severe hypocalcaemia secondary to the intestinal malabsorption of calcium with inflammatory bowel disease. The interesting feature of this case was the rapid haemodynamic deterioration and the total reversal within one week following correction of the hypocalcaemia.

Adult↗

PubMed2004

Saccharothrix algeriensis sp. nov., isolated from Saharan soil.

The taxonomic position of a soil isolate, strain SA 233T, recovered from Saharan soil from Algeria was established using a polyphasic approach. This isolate has been previously reported to produce three novel dithiolopyrrolone antibiotics, and preliminary chemotaxonomic and morphological characteristics suggested that it was representative of a member of the genus Saccharothrix. Phylogenetic analysis of the strain from 16S rDNA sequences, along with a detailed analysis of morphological, chemotaxonomic and physiological characteristics, indicates that it belongs to the genus Saccharothrix and represents a novel species that is readily distinguished from all recognized Saccharothrix species. The name Saccharothrix algeriensis sp. nov. is proposed for the isolate, with type strain SA 233T (=NRRL B-24137T=DSM 44581T).

Actinomycetales↗

PubMed2004

Ochratoxin A removal in synthetic and natural grape juices by selected oenological Saccharomyces strains.

AIMS: To assess, for the first time the efficiency in removing ochratoxin A (OTA) from laboratory medium [yeast peptone glucose (YPG)], synthetic grape juice medium (SGM) and natural grape juice by viable and dead (heat and acid-treated) oenological Saccharomyces strains (five S. cerevisiae and one S. bayanus) compared with a commercial yeast walls additive. METHODS AND RESULTS: Levels of OTA during its interaction with six oenological Saccharomyces strains (five S. cerevisiae and one S. bayanus) or with a commercial yeast walls additive in YPG medium, in SGM or in natural grape juices was assessed by HPLC after appropriate extraction methods. A significant decrease of OTA levels in YPG medium and SGM was observed for many of the growing strains reaching a maximum of 45%, but no degradation products were detected. With both heat and acid pretreated yeasts, OTA removal was enhanced, indicating that adsorption, not catabolism, is the mechanism to reduce OTA concentrations. Adsorption was also improved when the yeast concentration was increased and when the pH of the medium was lower. Approximately 90% of OTA was bound rapidly within 5 min and up to 72 h of incubation with heat-treated cells of either S. cerevisiae or S. bayanus. A comparative study between heat-treated cells (HC) and commercial yeast walls (YW) (used as oenological additive), introduced at two different concentrations (0.2 and 6.7 g l(-1)) in an OTA-contaminated grape juice, showed the highest efficiency by HC to adsorb rapidly within 5 min the total amount of the mycotoxin. CONCLUSIONS: Oenological S. cerevisiae and S. bayanus were able to remove ochatoxin A from synthetic and natural grape juices. This removal was rapid and improved by dead yeasts having more efficiency than commercial yeast walls. SIGNIFICANCE AND IMPACT OF THE STUDY: The efficiency of heat-treated yeasts to remove OTA gives a new hope for grape juice and must decontamination avoiding negative impacts on human health.

Adsorption↗

PubMed2004

[Syncope].

Syncope remains a clinical challenge. Accurate history taking, physical examination and EKG are mainstays of the diagnosis work up. The most important parameter for prognosis and requiring aggressive management is a structural heart disease. Patient without cardiopathy presenting multiple episodes may be candidate for tilt testing and loop EKG recorder.

Diagnosis, Differential↗

PubMed2001

Kashin-Beck disease: from etiology to prevention or from prevention to etiology?

The aetiology of Kashin-Beck disease (KBD) remains elusive. Four factors have been convincingly associated with the disease: selenium deficiency, iodine deficiency, grain contamination with mycotoxin-producing fungi, and water pollution with organic material and fulvic acid. The most credible studies from a scientific standpoint, i.e. randomised placebo controlled trials and observational cohort studies have either not been conducted or did not provide unequivocal demonstration in favour of any of these hypotheses. Many studies such as case-control, cross-sectional, "before-after", and even more so, ecological studies have been conducted. They merely produced weak evidence and fail to support any single factor to the exclusion of the others. The most scientifically sound studies have included animal models, laboratory experiments and pathology studies; however, these have only provided indirect evidence. Although none of the competing theories prevails when they are compared using a predefined and standard set of causality criteria (temporality, strength of the association, biological gradient, experimental evidence, biological plausibility, coherence, specificity and analogy), none should be discounted. This is an indication that a comprehensive and unifying theory is most likely to be multifactorial. Because the ultimate goal of those who are compelled by the challenge of KBD is to prevent its occurrence, a perfect understanding of its mechanisms is not indispensable for action. Well-conducted randomised intervention should be the priority of researchers as well as public health professionals to demonstrate what works and what does not.

Causality↗

PubMed2001

Histology of Kashin-Beck lesions.

There are few papers in existence describing the histopathology of Kashin-Beck disease. The few existing papers mention chondronecrosis within the epiphyseal primodium and metaphyseal cartilage. In the present study, two series of samples were available for histology: supernumerary fingers removed from young subjects and intra-articular bodies collected in more advanced cases of the disease. The prevailing characteristic of the samples is the absence of vascularisation within the proximal cartilage end plate of the phalanx associated with an alteration of the epiphyseal bone formation. These observations suggest that Kashin-Beck disease could develop from an alteration of the angiogenesis of the metaphyseal cartilage resulting in degeneration with consequent joint dysplasia, which may be associated with a decrease in growth of the diaphyseal bones.

Adolescent↗

PubMed2001

Anthropometry and clinical features of Kashin-Beck disease in central Tibet.

We compared two different populations living in central Tibet with the purpose of establishing standard values for different anthropometric parameters in a rural population. Later on, these values were used as references for a similar study on a KBD population. One group (KBD) (n=1,246) came from the endemic areas, and the other group, serving as the control population (n=815), came from non-endemic areas. Both groups included children and adults and were of the Mongoloid type; they were farmers or semi-nomads. Height, weight, segment length, joint perimeter, joint diameter, joint movement were recorded. Also more subjective information such as general feeling of tiredness, rapid fatigue at work, work limitation, joint pain, muscle weakness, muscular atrophy, dwarfism, flatfoot, and waddling gate was also collected. Those variables were compared between the two groups.

Adolescent↗

PubMed2001

Kashin-Beck disease and drinking water in Central Tibet.

A cross-sectional survey was carried out in order to study the relationship between Kashin-Beck disease and drinking water. The average volume of the water containers was larger in families unaffected by the disease. Organic material was measured by ultraviolet (UV) spectroscopy. The UV absorbency was significantly lower in drinking water of unaffected families. Thus, the organic material in drinking water may play a role in the pathogenesis of Kashin-Beck disease.

Cross-Sectional Studies↗

PubMed2001

Effects of physical therapy on patients with Kashin-Beck disease in Tibet.

A clinical trial of physical therapy treatment for patients suffering from Kashin-Beck disease (KBD) has been carried out in Tibet. One-hundred and thirty-five patients with Kashin-Beck disease were allocated to either physical therapy (72 patients) or prescription of multivitamins (63 patients). The patients were followed for 4 years. This study suggested a beneficial effect of physical treatment.

Adolescent↗

PubMed2001

Ethno-agricultural approach to the rural environment in the prevention of Kashin-Beck disease.

Kashin-Beck disease occurs in several villages of Tibet; however, its local importance varies greatly. The ecoclimatological as well as the phytogeographical framework of the studied area are presented. An ecological approach based upon the ethno-ecosystem concept was carried out in the vicinity of each village. This study identifies 18 vegetation units on a structural basis; they were named for the dominant plants of each unit. Half of them belonged to the aquatic milieu. The different factors controlling their distribution were also identified. Particular attention will be paid to the links between man and the environment, particularly regarding alternative food intakes and water supply access.

Agriculture↗

PubMed2001

Kashin-Beck disease and iodine deficiency in Tibet.

We evaluated iodine and selenium status in 575 children between 5 and 15 years with Kashin-Beck disease from endemic and non-endemic areas. Of these 267 (46%) children had goiter. The proportion of subjects with goiter was higher in the villages with Kashin-Beck disease than in the control village. In the villages with Kashin-Beck disease, 105 (23%) of the subjects had a serum thyrotropin greater than 10 mU/l as compared with 3 (4%) in the control village. The percentages of low serum thyroxine values and low serum tri-iodothyronine were greater in the villages where Kashin-Beck disease was endemic than in the control village. The percentages of low urinary iodine concentration were significantly greater in the subjects with Kashin-Beck disease. The results suggest that in areas where severe selenium deficiency is endemic, iodine deficiency is a risk factor for Kashin-Beck disease.

Adolescent↗