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Biomedical subjects

D K Rex

Publications and source records attributed to D K Rex.

104 records · Page 6Linked to original sources
PubMed1984

Purification and characterization of mouse alcohol dehydrogenase from two inbred strains that differ in total liver enzyme activity.

Alcohol dehydrogenase activity in mouse liver homogenate-supernatants is 1.7 times greater in the C57BL/10 strain than in the BALB/c strain, regardless of whether activity is expressed in units per gram liver, total liver, or milligram DNA. The Km values for ethanol and NAD+, approximately 0.4 and 0.03 mM, respectively, of enzyme purified from both strains are similar. Moreover, the Ki for NADH, 1 microM, the pH optimum for ethanol oxidation, 10.5, and the Vmax for ethanol oxidation, 160 min-1, for ADH from the C57BL/10 and BALB/c strains are similar. Therefore, the difference in ADH activity in the two strains cannot be due to differences in the catalytic properties of the enzyme. The electrophoretic and isoelectric focusing patterns and two-dimensional tryptic peptide maps of the purified enzyme from both strains are identical. Thus the amino acid sequences of enzyme from C57BL/10 and BALB/c mice must also be identical or very similar. The difference in ADH activity in the two strains is most likely the result of genetic differences in the content of ADH protein in liver.

Alcohol Dehydrogenase↗
PubMedDate not supplied

Performing screening flexible sigmoidoscopy using colonoscopes: experience in 500 subjects.

There is still controversy regarding the optimal length of flexible sigmoidoscopes. We performed screening distal colon examinations using 168-cm colonoscopes in 500 asymptomatic subjects who were unsedated and had sigmoidoscopy cleansing preparation. The mean depth of penetration was 66 cm and was similar in persons in whom the examination was discontinued because of poor preparation versus those with discomfort. Polyps were detected in 87 patients, but only 5 subjects had polyps detected above 60 cm. We conclude that in a group of unsedated subjects scheduled for flexible sigmoidoscopy after a sigmoidoscopy prep, the use of instruments longer than 60 cm gives very little additional yield.

Colonic Neoplasms↗
PubMedDate not supplied

Endoscopic ultrasonography as an adjunct to fine needle aspiration cytology of the upper and lower gastrointestinal tract.

Twenty consecutive patients with either extrinsic or submucosal masses or gastric ulcers suspicious for malignancy with previously negative conventional forceps biopsies and/or brush cytology underwent a combined approach of endoscopic ultrasound (EUS) followed by fine needle aspiration cytology. Diagnostic results were obtained in 17 of 20 patients. The three patients with indeterminate aspirates had EUS findings strongly supportive of the final diagnosis. EUS combined with fine needle aspiration cytology appears to be of value in the evaluation of extrinsic, submucosal, and ulcerative lesions of the gastrointestinal tract.

Biopsy, Needle↗
PubMedDate not supplied

Colonoscopy and endoscopic therapy for delayed post-polypectomy hemorrhage.

Nine consecutive patients in whom endoscopic management of delayed post-polypectomy hemorrhage was attempted are described. Each patient presented with active rectal bleeding 12 hours to 12 days after snare resection of a colon polyp. In each patient, repeat colonoscopy identified the bleeding site and various combinations of injection therapy, electrocautery, or thermal injury led to cessation of hemorrhage. No complications resulted from repeat colonoscopy and endoscopic therapy. Colonoscopy and endoscopic therapy is feasible, effective, and safe in selected patients with active delayed post-polypectomy hemorrhage.

Colonic Polyps↗
PubMedDate not supplied

Quality of air contrast barium enema performed the same day as incomplete colonoscopy with air insufflation.

The quality of 17 air contrast barium enemas performed the same day as incomplete colonoscopies using air insufflation was compared with 21 air contrast barium enemas performed on a different day from incomplete colonoscopies. A gastrointestinal radiologist blinded to the timing of the procedures reviewed the barium studies scoring them as 1 (unsatisfactory) to 4 (excellent) in four areas. The mean overall quality score for the air contrast barium enemas done the same day as incomplete colonoscopy was 3.29 vs. 2.97 for those done on a different day (p = 0.24). There were no significant differences in quality scores between same-day versus different-day air contrast barium enemas for the specific parameters of quality of distention, barium coating, and amount of spasm. We conclude that when colonoscopy using air insufflation is incomplete because of looping or angulation, air contrast barium enema can be done the same day without impairing the quality of the barium study.

Air↗
PubMedDate not supplied

Alcohol and aldehyde dehydrogenase isoenzymes in North American Indians.

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) isoenzyme phenotypes were determined in autopsy liver samples from 50 North American Indians from New Mexico. Forty-six of the 50 livers had sufficient ADH activity to allow phenotyping at the ADH2 and ADH3 loci. All 46 livers possessed the "typical" ADH2 1-1 phenotype. The frequency of the ADH3(2) allele was 0.59 and is the highest thus far reported in any racial population. All 50 livers possessed the ALDH I isoenzyme which exhibits the greatest anodic mobility on starch gel electrophoresis at pH 7.6. The results show that ADH and ALDH phenotypes among American Indians living in New Mexico are very similar to those of Caucasian populations and quite different from those of Orientals.

Adolescent↗
PubMedDate not supplied

Clinical utility of enteroclysis.

The incidence of pathology in the small bowel is substantially lower than in the upper gastrointestinal tract or colon. This is fortunate since the small bowel, with its unique anatomy and remote location is the most difficult section of the gastrointestinal tract to study. Instillation of contrast into the small bowel lumen can be achieved by the oral route or by the more recently refined technique of small bowel intubation/infusion called enteroclysis. This brief review will focus on the clinical infusion indications for and efficacy of enteroclysis and the relative advantages of enteroclysis over oral methods of small bowel radiography.

Crohn Disease↗
PubMedDate not supplied

Endoscopic screening for colorectal cancer: recent studies from Indiana University.

Fecal occult blood testing is inadequate as a sole screening measure for colorectal cancer. Endoscopic screening and adenoma removal is now proven to reduce colorectal cancer mortality. At the Indiana University Colorectal Cancer Screening Center, studies have clarified several issues regarding endoscopic screening for colorectal cancer. Screening colonoscopy in 621 asymptomatic adults aged 50 to 75 years demonstrated that 27% had colonic adenomas. Increasing age and male gender were both powerful predictors of an increased prevalence of colonic adenomas. A family history of a single first-degree relative who developed colorectal cancer at age 60 or older did not predict a higher prevalence of colonic adenomas. All cancers and all adenomas greater than or equal to 1 cm in size found in average-risk persons were found in persons aged 60 or older. Half of the people with adenomas had no neoplasia within reach of the flexible sigmoidoscope. Based on these findings, we have suggested that a single screening colonoscopy performed in average-risk person in their early sixties may be an effective method to reduce colorectal cancer mortality. In the screening colonoscopy study, distal colonic hyperplastic polyps were shown to not predict proximal colon adenomas. Therefore, colonoscopy is not warranted when only hyperplastic polyps are detected by flexible sigmoidoscopy in asymptomatic, average-risk people. Screening sigmoidoscopic exams using colonoscopes showed that 60 cm scopes have the optimal length for flexible sigmoidoscopy in unsedated patients. Finally, a screening colonoscopy study demonstrated that women with a personal history of breast cancer do not have an increased prevalence of colonic adenomas.

Aged↗