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Biomedical subjects

K Sheahan

Publications and source records attributed to K Sheahan.

44 records · Page 3Linked to original sources
PubMed1989

Associations between smoking status and stage of colorectal cancer at diagnosis in Massachusetts between 1982 and 1987.

To examine the relationship between smoking and stage of colorectal cancer at diagnosis, data on 2788 current smokers and 6313 nonsmokers with known stage at diagnosis were obtained from the Massachusetts Cancer Registry. The stage at diagnosis was treated as a polytomous response variable in a logit-type, log-linear (Poisson) model, with smoking status, age, sex, and race as covariates. The relative frequency of disseminated colorectal cancer was 45% greater in smokers, compared with nonsmokers (relative risk [RR] = 1.45; 95% confidence interval, 1.00 to 2.09). A substudy was conducted to determine the accuracy of the registry's smoking data; the findings suggest that the actual association may be larger than that presented above. These results confirm the presence of an association between smoking and advanced stage of colorectal cancer at diagnosis. Whether the association is due to a biologic or behavioral phenomenon cannot be determined from these data.

Aged↗
PubMed1989

Cysteine protease activities and tumor development in human colorectal carcinoma.

Many studies of malignant cells or tissues in culture have implicated cysteine proteases in the progression of malignancy. We have extended these observations by measuring quantitative and qualitative changes in the expression of cathepsin B-like and L-like cysteine proteases during the growth and development of human colorectal carcinomas. Data derived from matched pairs of normal colorectal mucosa and carcinoma tissue from 27 patients demonstrated that both cathepsin B-like and cathepsin L-like specific activities were significantly elevated (P less than 0.005) in the carcinoma tissue, while levels of endogenous cysteine protease inhibitor remained constant. Correlation of cathepsin enzyme activities with different stages of colorectal cancer demonstrated significantly higher cysteine protease activities in individuals with Dukes' A tumors (tumors confined to the bowel wall) than in patients with more advanced tumors (Dukes' B, C, or D tumors) (P less than 0.01-0.05). The relative proportion of activities contained in tumor epithelial and stromal elements remains to be elucidated. These results suggest an important role for cysteine proteases in the early progression of human colorectal carcinoma.

Adenocarcinoma, Mucinous↗
PubMed1988

Inflammatory pseudotumor of the spleen: a clinicopathology study of three cases.

The clinical and pathologic findings of three cases of splenic inflammatory pseudotumor are described, and differential diagnostic features are discussed. This benign lesion is extremely rare, only four having been previously reported. Inflammatory pseudotumors often pose diagnostic difficulties because they form infiltrative masses which have clinical and gross pathologic features that suggest malignancy. Although these lesions are usually easily recognizable microscopically as benign processes, the admixed component of lymphoid and other hematopoietic cells may sometimes raise the question of a lymphoreticular malignancy, requiring immunohistologic studies for resolution in some cases. Alternatively, pseudotumors may be mistaken for infectious granulomatous processes, sarcoidosis, or hamartomas.

Adult↗
PubMed1987

Functional oncocytoma of the kidney: evaluation by dual tracer scintigraphy.

We report a case of renal oncocytoma with a unique scintigraphic pattern. The tumor showed strong avidity for [123I]iodohippurate, but no affinity for [99mTc] glucoheptonate. We offer an explanation for such exceptional scintigraphic finding, which may potentially enable us to make a pre-operative diagnosis of renal oncocytoma in the future.

Adenoma↗
PubMedDate not supplied

Ret-proto-oncogene analysis in medullary thyroid carcinoma.

INTRODUCTION: Medullary carcinoma of the thyroid (MTC) is a rare tumour which occurs in both sporadic and hereditary forms. Mutations of the RET proto-oncogene have been identified in hereditary forms. The aim of our study was to confirm or exclude familial disease by examining for germline mutations in the RET proto-oncogene in patients with medullary thyroid carcinoma. METHODS: Nine patients with medullary thyroid carcinoma and 4 of their children were studied. Peripheral blood was used to examine for mutations in the RET proto-oncogene. When this was not available, archival thyroid tissue was used. RESULTS: Seven patients had clinically sporadic tumours confirmed by mutational analysis of RET. Four children were at risk of being carriers of a mutated gene, as their fathers had histologically proven MTC and had tested positive for the mutation at codon 618 on exon 10 of the RET proto-oncogene. Three of these children carried the 618 mutation. To date, 2 have had a prophylactic thyroidectomy, the pathology of which revealed C-cell hyperplasia. One child had familial disease excluded by mutational analysis. One patient had a clinical diagnosis of MEN2B confirmed by detection of the 918 mutation on exon 16 of the RET proto-oncogene. CONCLUSIONS: RET proto-oncogene analysis is a reliable method of differentiating familial from sporadic MTC. Mutational information determines which family members of affected kindreds are at risk of developing the disease and can be used to affect clinical management.

Adolescent↗
PubMedDate not supplied

Evidence for the polyp-cancer sequence in gallbladder cancer.

We report a patient with symptomatic biliary disease and who was diagnosed by ultrasound to have a large polypoid gallbladder lesion. Histopathology revealed adenoma in combination with carcinoma in situ. The evidence for the adenoma-carcinoma sequence in gallbladder cancer and diagnostic and therapeutic implications are discussed.

Adenocarcinoma↗