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Biomedical subjects

T R Williams

Publications and source records attributed to T R Williams.

81 records · Page 5Linked to original sources
PubMedDate not supplied

Fibroepithelial polyps of the urinary tract.

BACKGROUND: Fibroepithelial polyps of the urothelium are rare but frequently mistaken for transitional cell carcinoma. To better define the demographics, urothelial distribution, and typical gross anatomic and radiologic appearances, we reviewed 41 pathologically proven cases. METHODS: We reviewed 41 cases of fibroepithelial polyps from the archives of the Armed Forces of Pathology. Data were collected from radiographic studies, gross anatomic pathology, and pathology and radiology reports and categorized by age, sex, clinical presentation, lesion size, location, and morphology. RESULTS: The mean patient age was 21 years, and 58% were male. Most presented with hematuria and/or flank pain (68%). Most polyps were located in the upper ureter or renal pelvis (87%). Posterior urethral and bladder polyps were present in children. Most polyps were single or bilobed (73%) and 1-6 cm. CONCLUSION: Because most urothelial tumors are malignant epithelial tumors, fibroepithelial polyps are commonly mistaken for transitional cell carcinomas. However, because fibroepithelial polyps and malignant urothelial tumors typically present in different patient populations, different locations in the urinary tract, and appear different radiographically, distinguishing features between these entities is helpful in determining the differential diagnosis of a urothelial mass. In the appropriate clinical setting, fibroepithelial polyps should be considered in the differential diagnosis, which will affect surgical treatment.

Adolescent↗
PubMedDate not supplied

Diffuse esophageal stricture secondary to esophageal lichen planus.

There are many well-known causes of diffuse esophageal stricture, including lye burns, reflux, radiation, and several mucocutaneous diseases. We report a case of esophageal stricture secondary to lichen planus. Esophageal lichen planus is rare and frequently mistaken for other more common disorders such as gastroesophageal reflux disease, which delays diagnosis and appropriate treatment, but it should be considered in female patients with cutaneous and oral lichen planus.

Catheterization↗
PubMedDate not supplied

Effect of vitamin A on longevity.

Increasing the dietary content of Vitamin A from inadequate to adequate during the developmental stages of Drosophila increased the median life span by as much as 17.5%. The optimum dietary range of concentrations of Vitamin A for increasing the life span of Drosophila was found to be between 4 and 8 IU/g food. The maximum life span was reduced as dietary concentrations of Vitamin A exceeded this value. Vitamin A palmitate and retinal inhibited the peroxidation of linolenic acid induced by the generation of superoxide radicals from acetaldehyde. Other forms of Vitamin A, such as retinol and retinoic acid, moderately inhibited lipid peroxidation at low concentrations but stimulated peroxidation considerably when present at high concentrations. Based upon the ability of these retinoids to inhibit the reduction of cytochrome c by superoxide radicals, we propose that retinoids can inhibit and stimulate lipid peroxidation depending upon their concentration by reacting with superoxide radicals. We suggest that this reaction is the basis for the apparent ability of Vitamin A to prolong and shorten life span depending upon the dietary intake.

Animals↗
PubMedDate not supplied

Kinetic determination of granulocyte alkaline phosphatase by the GEMSAEC.

Granulocyte alkaline phosphatase (ALP) activity is measured kinetically using the GEMSAEC centrifugal analyzer and p-nitrophenylphosphate as substrate. Measurements of enzyme activity are made at pH 9.8 utilizing 1.0 M diethanolamine as a buffer containing 0.5 mM magnesium chloride. Granulocytes are separated from heparinized blood using dextran sedimentation, followed with ficoll-hypaque separation. The separated cells are suspended in saline, and the red cells are lysed. Manual counting of stained smears of the cells isolated showed that 95 percent of these cells were granulocytes. After lysing the red cells, the granulocyte suspension is rinsed in 12.5 percent heat inactivated serum in saline and separated by centrifugation. After 200 microliters of the diluent solution (12.5 percent heat inactivated serum in saline) is added to the cells, they are sonicated for seven sec at 0 degrees in an ice bath. The extracts are then assayed kinetically for ALP activity. Granulocyte ALP activity varies from day to day in normal individuals. The daily variation of ALP activity observed correlates closely with and is confirmed by the Sigma Histochemical Procedure based on Kaplow' Scoring Method. The coefficient of variation of the ALP method within assay performed on two consecutive days on a pooled sample is 0.75 percent and 1.38 percent, respectively, and between assays 4.82 percent.

Adult↗