Biomedical subjects

T S Lau

Publications and source records attributed to T S Lau.

5 recordsLinked to original sources

PubMed1992

Mucin associated Tn and sialosyl-Tn antigen expression in colorectal polyps.

Sialosyl-Tn antigen and its immediate precursor, Tn antigen, are carbohydrate structures associated with the earliest steps of mucin O-linked glycosylation. Both antigens have been shown previously to be highly sensitive and specific markers of colorectal cancer. One hundred and three colorectal polyps (79 adenomatous; 24 hyperplastic) were examined for expression of Tn antigen using vicia villosa isolectin B4, and for sialosyl-Tn antigen by monoclonal antibody TKH2. Tn antigen was expressed by all of the polyps studied. Sialosyl-Tn, on the other hand was expressed weakly by a few cells in 7 of 24 (29%) hyperplastic polyps. Among the adenomatous polyps, 56% expressed sialosyl-Tn and expression correlated with larger adenoma size, greater villous component, and more severe grades of dysplasia. In individuals with two or more synchronous adenomas, the level of sialosyl-Tn expression within an adenoma was associated with the severity of cytological atypia. All the adenomas that contained a focus of invasive carcinoma expressed sialosyl-Tn. These results indicate that colorectal polyps manifest incomplete glycosylation, exposing antigens in the innermost region of mucin oligosaccharides. In addition, the correlation of sialosyl-Tn antigen expression with the adenoma-carcinoma sequence may make this a useful marker for studying malignant progression in the colon.

Antigens, Neoplasm↗

PubMed1991

Radiation-induced meningiomas: experience at the Mount Sinai Hospital and review of the literature.

From the records of The Mount Sinai Hospital, seven cases which met established criteria for radiation-induced meningiomas were identified. This represents the largest series of radiogenic meningiomas documented in North America and includes both intracranial and intraspinal tumors. The records and pathological specimens were reviewed and these data analyzed with other cases retrieved from the world literature. This study reveals that radiation-induced meningiomas can be categorized into three groups based on the amount of radiation administered: 1) low dose; 2) moderate dose and miscellaneous; and 3) high dose. The overwhelming majority of cases had received low-dose irradiation (800 rad) to the scalp for tinea capitis and the second largest group resulted from high-dose irradiation for primary brain tumors (greater than 2000 rad). The unique features distinguishing radiation-induced meningiomas from other meningiomas are reviewed. Although histologically atypical tumors were common in this series, overt malignancy was not encountered. The preoperative management of these lesions should include angiography to evaluate for large-vessel occlusive vasculopathy, a known association of meningiomas induced by high-dose irradiation. Given the propensity these tumors possess for recurrence, a wide bony and dural margin is recommended at surgical resection.

Adult↗

PubMed1991

On dependent repeated screening tests.

A screening test is applied n times to a person with known true status. If more than k tests have positive outcomes, then the person is assigned to be screen-positive; otherwise, the person is assigned to be screen-negative. Assuming that the tests are exchangeable, we can characterize the possible dependence among tests by at most n parameters called canonical moments, which can be estimated from the data. The performance characteristics of the composite test (such as likelihood ratios, sensitivity, and specificity) can be computed based on these estimates. Thus, we can choose n and k so that the desired levels of likelihood ratios, sensitivity, and specificity can be achieved. We study the cases n = 2 and n = 3 in detail.

Biometry↗

PubMed1976

Cysticercosis.

Explore the source record for details and available documents.

Adult↗

PubMed1976

Insulin metabolism in depancreatized dogs during hemorrhagic shock.

This study was done to determine why the plasma insulin remained elevated during shock. Mongrel Female dogs (12-15 kg) were depancreatized and maintained on a constant intraportal infusion of porcine insulin while they were bled to reduce and maintain the mean arterial blood pressure at 50 mm Hg for 165 min. Blood samples were taken for glucose and plasma insulin at 15 min intervals. The data show that there was a progressive rise of plasma insulin during the course of hemorrhagic shock. This occurred despite a constant infusion of insulin, the sole source of insulin available to these depancreatized dogs. Since removal of plasma insulin is largely due to insulin utilization, our findings imply that the rise of plasma insulin in hemorrhagic shock is caused by decreased utilization.

Animals↗