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Biomedical subjects

D Ouellette

Publications and source records attributed to D Ouellette.

10 recordsLinked to original sources
PubMed2001

Selection of specific endophytic bacterial genotypes by plants in response to soil contamination.

Plant-bacterial combinations can increase contaminant degradation in the rhizosphere, but the role played by indigenous root-associated bacteria during plant growth in contaminated soils is unclear. The purpose of this study was to determine if plants had the ability to selectively enhance the prevalence of endophytes containing pollutant catabolic genes in unrelated environments contaminated with different pollutants. At petroleum hydrocarbon contaminated sites, two genes encoding hydrocarbon degradation, alkane monooxygenase (alkB) and naphthalene dioxygenase (ndoB), were two and four times more prevalent in bacteria extracted from the root interior (endophytic) than from the bulk soil and sediment, respectively. In field sites contaminated with nitroaromatics, two genes encoding nitrotoluene degradation, 2-nitrotoluene reductase (ntdAa) and nitrotoluene monooxygenase (ntnM), were 7 to 14 times more prevalent in endophytic bacteria. The addition of petroleum to sediment doubled the prevalence of ndoB-positive endophytes in Scirpus pungens, indicating that the numbers of endophytes containing catabolic genotypes were dependent on the presence and concentration of contaminants. Similarly, the numbers of alkB- or ndoB-positive endophytes in Festuca arundinacea were correlated with the concentration of creosote in the soil but not with the numbers of alkB- or ndoB-positive bacteria in the bulk soil. Our results indicate that the enrichment of catabolic genotypes in the root interior is both plant and contaminant dependent.

Bacteria↗
PubMed2001

Open antireflux repairs for simple reflux esophagitis: short- and long-term results.

This analysis of the results of open antireflux surgery clearly shows a benefit for antireflux surgery in most patients who have severe esophagitis with or without hiatal hernia. The authors of this article have found many variations in the methodology used to evaluate these results. Aside from these problems, however, the authors also have noticed the remarkably serious and honest work performed by most surgeons in trying to report the truth with the methodologies available to them. The principles of antireflux surgery can be found among the different studies that are reviewed in this article. These principles include: 1. The necessity of closing the crura; 2. The importance of repositioning the distal esophagus into the abdominal cavity; 3. The necessity of increasing the LES pressure by using the musculature of the fundus; 4. The preference for using a short and floppy fundoplication to avoid side effects; and 5. The need for long-term follow-up in evaluating results.

Esophagitis, Peptic↗
PubMed1999

D4 dopamine receptor-mediated phospholipid methylation and its implications for mental illnesses such as schizophrenia.

Previous studies have shown D2-like dopamine receptor involvement in the regulation of phospholipid methylation (PLM), while others have documented impaired methionine and folate metabolism in schizophrenia. Utilizing [14C]formate labeling in cultured neuroblastoma cell lines, we now show that D4 dopamine receptors (D4R) mediate the stimulatory effect of dopamine (DA) on PLM. The effect of DA was potently blocked by highly D4R-selective antagonists and stimulated by the D4R-selective agonist CP-226269. DA-stimulated PLM was dependent upon the activity of methionine cycle enzymes, but DA failed to increase PLM in [3H]methionine labeling studies, indicating that a methionine residue in the D4R might be involved in mediating PLM. A direct role for MET313, located on transmembrane helix No. 6 immediately adjacent to phospholipid headgroups, was further suggested from adenosylation, site-directed mutagenesis and GTP-binding results. A comparison of PLM in lymphocytes from schizophrenia patients vs control samples showed a four-fold lower activity in the schizophrenia group. These findings reveal a novel mechanism by which the D4R can regulate membrane composition. Abnormalities in D4R-mediated PLM may be important in psychiatric illnesses such as schizophrenia.

Amino Acid Sequence↗
PubMed1998

Lung cancer in women compared with men: stage, treatment, and survival.

BACKGROUND: In cardiac disease there appears to be a difference in the treatment of men and women, and thus an advantage in survival in men. This study aimed to determine whether these differences exist in lung cancer. METHODS: We undertook a retrospective cohort study in a university hospital. The study population consisted of 104 consecutive women and 104 consecutive men with newly diagnosed lung cancer between March 1988 and June 1990. The following information was collected: sex, age, presenting symptoms, investigations, histology, stage, treatment, and survival. RESULTS: The location of the tumor, presenting symptoms, investigations, and stages were similar in men and women. There was a difference in the distribution of the various histologic types of lung cancer: Small cell lung cancer was more frequent in women (25% versus 11.5% in men) and squamous cell carcinoma more frequent in men (38% in women versus 51% in men). The overall survival was similar among the two sexes, but there was a survival advantage in women when adjusted for stage. CONCLUSIONS: There was a higher incidence of small cell carcinoma in women and squamous cell carcinoma in men. There was evidence of a difference in the survival rate of lung cancer in favor of women according to stage.

Bias↗
PubMed1997

Bowel preparation with polyethylene glycol electrolyte lavage solution is potentially hazardous in patients with carcinoma of the cardia: a case report.

Polyethylene glycol (PEG) electrolyte solution can induce potentially fatal complications when used as a lavage in preoperative bowel preparation. A 60-year-old man with carcinoma of the esophagogastric junction had a Mallory-Weiss tear after bowel preparation with PEG. He was successfully resuscitated, first with balanced salt solution then by transfusion. The literature on the subject is reviewed and recommendations are made, which include consideration of alternative methods of bowel preparation (e.g., sodium phosphate solution) in patients with esophageal obstruction.

Adenocarcinoma↗
PubMed1995

[Endoscopic YAG laser and palliative therapy of cancer of the esophagus].

In our institution, the YAG laser has been used to treat 110 patients with inoperable esophageal carcinoma. Therapy was palliative as patients presented metastases (41.8%), advanced systemic disease (22.7%), extensive local disease (18.2%) or recurrent carcinoma (10%). The study group included 92 men (mean age 68.4 years) and 18 women (mean age 67.0 years); 47.3% of the patients had received no previous treatment while 52.7% had been treated previously with either radiotherapy, chemotherapy, surgery, stents or dilatation. The majority of lesions were adenocarcinomas (57.3%) with squamous cell carcinomas in 37.3%; 66.3% of cancers were located in the distal third of the esophagus. The patients received a mean of 2.4 laser treatments with 4883 joules per treatment on average. The rate of major complications was 2.7% and the rate of mortality 1.8%. The median survival for the group was 4.5 months. No significant difference was found in the length of survival according to the histology of the tumour (p = 0.35), the presence of metastases (p = 0.24) and the association of other treatment modalities with the laser (p = 0.06). Functional results were considered good to excellent in 82.1% of cases. In conclusion, the YAG laser does not influence overall survival of inoperable patients, but this therapy is effective and safe and is presently the treatment of choice for these patients.

Adenocarcinoma↗