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Biomedical subjects

C Dupont

Publications and source records attributed to C Dupont.

At least 163 records · Page 9Linked to original sources
PubMed1996

Effect of BN 50727 on pathological findings and tissue platelet activating factor levels during ileal ischemia in newborn piglets.

The role of platelet activating factor (PAF), a potent ulcerogen mediator in the digestive tract, is thought to be important in the genesis of necrotizing enterocolitis. The aim of this study was to evaluate the role of PAF in the perpetuation and aggravation of gastrointestinal damage resulting from limited ischemia in the 2-day-old piglet using a natural PAF antagonist (BN 50727). Animals were separated into six groups: U4, controls; S, sham operated animals undergoing laparotomy; I4 and I9, ligation of the mesenteric vessels in the last ileal loop; IT4 and IT9, same procedure together with treatment with BN 50727 (50 mg/kg) orally before and after surgery and intraperitoneally during surgery. Animals were killed at day 4 in groups U4, S, I4 and IT4 and at day 9 in groups I9 and IT9, with histological studies and mediator measurements taken. Macroscopic and histological lesions of intestinal wall in groups I4, I9, IT4 and IT9 were similar to those of human neonatal necrotizing enterocolitis and did not vary according to the absence or the presence of BN 50727 treatment (P = .7, I4 v IT4 and P = .9, I9 v IT9). Peritoneal bands were significantly reduced in treated groups IT4 and IT9 as compared with untreated ones I4 and I9 (P = .003). Mucosal PAF levels in the terminal ileum were higher in group I4 than in groups U4 or I9. In the upper loop, mucosal PAF levels were comparable in all groups. An increase in stool PAF levels was observed only in group I9 (26.4 ng/g v 4.7 ng/g, I9 v U4 + S, P < .05), whereas values comparable to those observed in controls were detected in other groups (I4, 7.2 ng/g; IT4, 4.5 ng/g; IT9, 6.8 ng/g). Tumor necrosis factor alpha (TNF alpha) measurements did not exhibit any difference between groups. Using a PAF antagonist, the role of PAF in the aggravation of intestinal damage after ischemia was not remarkable because treatment did not induce any modifications of parietal intestinal lesions. PAF antagonists appeared to reduce significantly the local peritoneal consequences of local inflammation.

Animals↗
PubMed1996

Small-bowel bacterial overgrowth in children with chronic diarrhea, abdominal pain, or both.

OBJECTIVE: To evaluate the frequency of small-bowel bacterial overgrowth (SBBO) as a cause of chronic digestive symptoms in a large cohort of children, using the glucose breath hydrogen test (BHT). DESIGN: Patients were 53 children (aged 2 months to 12 years) with chronic diarrhea, abdominal pain, or both. Diagnosis of SBBO was defined with a BHT by a change in H2 concentration of 10 ppm H2 or more in expired air after an oral glucose load. Patients with a positive BHT result were included in group 1 and treated with a combination of colistin and metronidazole for 10 days; a second BHT was performed 1 month later. Group 2 comprised patients with a negative BHT result. Group 3 (n = 15) was a control group of healthy subjects, and group 4 (n = 6) a comparison group of subjects with bacteriologically documented SBBO. RESULTS: Eighteen patients (34%) had a positive BHT result and 35 a negative result. The BHT results were comparable in groups 1 and 4 and in groups 2 and 3, respectively. Fasting H2 levels were higher in group 1 than in groups 2 (p < 0.001) and 3 (p < 0.01). In group 1, children were younger than in group 2 (1 +/- 1 year vs 3.9 +/- 3 years; p < 0.001) and diarrhea was frequent (83%), but 17% of patients had abdominal pain alone. Fetid stools (p < 0.01), mucus in stools (p < 0.01), and flatulence (p < 0.05) were more frequent in group 1 than in group 2. Antibiotic treatment of children in group 1 led to a rapid disappearance of symptoms and normalization of BHT results. CONCLUSION: SBBO appears to be a frequent cause of chronic digestive symptoms in children, especially before the age of 2 years. The BHT provides a simple and noninvasive method of detecting it. The recognition of SBBO in children leads to effective treatment.

Abdominal Pain↗
PubMed1996

The threshold for immune cell reactivity to milk antigens decreases in cow's milk allergy with intestinal symptoms.

BACKGROUND: In cow's milk allergy (CMA) with intestinal symptoms, peripheral blood mononuclear cells (PBMCs) secrete tumor necrosis factor-alpha (TNF-alpha), altering intestinal function. However, the type of cow's milk protein (CMP) that triggers symptoms (intact or intestinally processed) is not known, and neither is the minimal amount required. METHODS: PBMCs were isolated from infants with active CMA or cured infants just before a new challenge and stimulated with intact or intestinally processed CMP. Supernatants were tested for cytokine content and for their ability to perturb intestinal barrier capacity, measured in Using chambers in HT29-19A intestinal cells. RESULTS: PBMCs from infants with active CMA secreted more TNF-alpha, when they were stimulated with intact rather than intestinally processed CMPs, and more TNF-alpha than PBMCs from cured infants. Accordingly, supernatants from PBMCs stimulated with intact but not intestinally processed CMPs significantly increased intestinal permeability. The CMP concentration required to trigger TNF-alpha secretion capable of altering intestinal function was very small in infants with active CMA (approximately 2 micrograms/ml), but about 300 times higher in cured infants. CONCLUSION: Intact rather than intestinally processed proteins stimulate PBMCs to release TNF-alpha and alter intestinal barrier capacity. The threshold for PBMC reactivity to milk antigens drops considerably during active CMA with intestinal symptoms.

Animals↗
PubMed1996

Unusual presentation of a tuberculous peritonitis in a patient with concomitant AIDS and liver cirrhosis.

We report a case of tuberculous peritonitis in a patient with concomitant HIV infection and liver cirrhosis. A 50-year-old man with viral B and delta liver cirrhosis and AIDS was diagnosed with spontaneous Escherichia coli peritonitis and successfully treated with beta-lactamins. Three months later, ascites reappeared and Mycobacterium tuberculosis was identified in peritoneal fluid cultures. The triple antituberculosis regimen was adjusted to his level of liver failure but the patient died of hepatic encephalopathy. Concomitant HIV infection and liver cirrhosis favour tuberculous peritonitis but they also make its diagnosis extremely difficult. Considering the poor prognosis of this infection when untreated, tuberculous peritonitis should be systematically suspected in such patients.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Current concepts and issues in the management of regurgitation of infants: a reappraisal. Management guidelines from a working party.

Regurgitation in infants is a common problem. Recent issues, such as the increased risk of sudden infant death in the prone sleeping position, the finding of persisting occult gastro-oesophageal reflux with feed thickeners, and the increasing awareness of the cost-benefit ratio of medications may challenge the currently recommended management approach. A round table was organized to elaborate on the impact of (i) the pro supine sleeping campaigns in relation to sudden infant death and (ii) advancement in medical treatment on therapeutic strategies in regurgitating infants. The participants were opinion leaders from Europe and North America (Belgium, Canada, France, UK, Italy, Switzerland and The Netherlands). The importance of parental reassurance is stressed. As a consequence of the supine sleeping campaigns aiming to decrease the incidence of sudden infant death syndrome, the "prone elevated sleeping position" is no longer advised as a first-line therapeutic approach, although it is still recommended in "complicated reflux". It is emphasized that milk thickeners are an adequate therapeutic tool for regurgitation, but not in reflux disease. According to the literature, the efficacy of (alginate )antacids, although very popular in some countries, is questionable. These recommendations will be of interest to first-line paediatricians, since about 40% of their patients, according to the literature, present because of regurgitation.

Anti-Ulcer Agents↗
PubMed1996

Improved Production of Mannanase by Streptomyces lividans.

Replacement of the natural promoter of the (beta)-mannanase gene of Streptomyces lividans by lacp resulted in a 15-fold increase in enzyme production over that of the previously reported clone S. lividans IAF36, a clone carrying multiple copies of manA, and a 350-fold increase over that of the wild-type strain S. lividans 1326. In addition, the use of lacp in the shuttle vector pIAF199 allowed synthesis of the enzymes on carbon sources that did not contain mannan, such as xylan and whey, which offers interesting possibilities for industrial production of the enzyme.

Journal Article↗
PubMed1996

Microbiological findings about pulmonary cryptosporidiosis in two AIDS patients.

There is no known treatment for pulmonary cryptosporidiosis, a rare complication of intestinal cryptosporidiosis in AIDS patients. We report two cases of cryptosporidiosis which were unusual because (i) extracellular invasive forms of the parasite were found in the bronchoalveolar lavage and (ii) the outcome was favorable in one patient after treatment with azithromycin.

AIDS-Related Opportunistic Infections↗
PubMed1996

Reversible model of magnesium depletion induced by systemic kainic acid injection in magnesium-deficient rats: I--Comparative study of various magnesium salts.

We developed three models of reversible magnesium depletion in rats resulting from the combined effects of kainic (KA) acid with magnesium deficiency, in order to compare the effects of various common magnesium salts (pidolate, aspartate, lactate, gluconate and chloride) and of magnesium acetyl taurinate (MgATa), administered daily (14 mg Mg2+, PO) for ten days. First, the immediate effects (wet dog shakes, clonic convulsions and death 1 h after injection) and late effects (fall from hole board between the second and tenth days post injection) of kainic acid at three different doses (3.6 and 11 mg/kg) were studied in magnesium deficient rats (50 ppm for 40 days) and in non-deficient rats (1700 ppm). The results showed that the effects of kainic acid were enhanced in magnesium deficient rats. Secondly, after ten days of physiological then pharmacological doses of magnesium, used as chronical supplementation, we showed that kainic acid administration combined with magnesium deficiency led to magnesium depletion of increasing severity depending on the dose of kainic acid. The observed magnesium depletions were weak at a dose of 3 mg/kg KA, moderate at a dose of 6 mg/kg and severe at a dose of 11 mg/kg. These depletions were more or less reversible, and this enabled the classification of the therapeutic effects of these salts on Mg depletion. Among common salts, magnesium pidolate presented the greatest efficacy but none of them fully prevented depletion. In contrast, MgATa was efficient on all the aspects of depletion, when administered preventively both chronically or acutely or as a single curative injection. Consequently the results we obtained in the present study, on a new model of magnesium depletion, showed the greatest efficacy of magnesium acetyl taurinate we demonstrated yet on other models of reversible magnesium depletion.

Administration, Oral↗
PubMed1995

Mutational analysis of the roles in catalysis and substrate recognition of arginines 54 and 305, aspartic acid 309, and tryptophan 317 located at subsites 1 and 2 in glucoamylase from Aspergillus niger.

The mutants Arg54-->Leu, Arg54-->Lys, Arg305-->Lys, Asp309-->Glu, and Trp317-->Phe, located at subsites 1 and 2 in glucoamylase from Aspergillus niger, provide insight into the importance of specific hydrogen bonds and hydrophobic interactions in substrate recognition, catalytic mechanism, and stability. As suggested from the crystal structure of a closely related glucoamylase [Aleshin, A. E., Firsov, L. M., & Honzatko, R. B. (1994) J. Biol. Chem. 269, 15631-15639], Arg54 in subsite 1 hydrogen bonds to the key polar group 4'-OH of maltose. The two mutants of Arg54 display losses in transition-state stabilization of 16-21 kJ mol-1 in the hydrolysis of different maltooligodextrins, which originate from a [(1.2-1.8) x 10(3)]-fold reduction in kcat and changes in Km ranging from 25% to 300% of the wild-type values. Arg305 similarly hydrogen bonds to 2'-OH and 3-OH, located at subsites 1 and 2, respectively. Arg305-->Lys glucoamylase is not saturated at concentrations of maltose or maltoheptaose of 400- and 40-fold, respectively, the Km of the wild-type enzyme. This mutant also has highly reduced kcat. On the other hand, for the alpha-1,6-linked isomaltose, the Lys305 mutant surprisingly has the same Km as the wild-type enzyme, while kcat is 10(3)-fold reduced. Arg305 is thus an important determinant in the distinction of the alpha-1,4 to alpha-1,6 substrate specificity. Arg305 interacts electrostatically and hydrophobically with the side chains of Asp309 and Trp317.(ABSTRACT TRUNCATED AT 250 WORDS)

Arginine↗
PubMed1995

Diagnostic procedures of GER in childhood lung disease.

Respiratory diseases are frequently related to gastroesophageal reflux (GER). In the absence of classic symptoms like vomiting, silent GER can only be ruled out by further studies. Esophageal pH monitoring of long duration (18 to 24 hr) is now recommended as the technique of choice in infants and children with atypical presentation of GER. Mechanisms of GER pathway are complex and may provoke chronic pneumonia or wheezing; pH monitoring cannot be considered an "all or nothing" exam. Several esophageal pH profiles have been described in various respiratory diseases.

Child↗