Biomedical subjects
I Finseth
Publications and source records attributed to I Finseth.
Ultrastructural morphometry of thyroid neoplasms.
This paper presents the first comprehensive morphometry analysis of normal thyroid, adenomas, and follicular and papillary carcinomas. The mean nuclear volume and the mean nuclear surface increased, while the volume densities of rough endoplasmic reticulum and dense bodies decreased from normal thyroid through adenomas and follicular carcinomas to papillary carcinomas. The different amounts of cytoplasmic organelles probably are related to endocrine function rather than to malignant potential. Papillary carcinomas with a predominantly follicular growth pattern are related more closely to follicular carcinomas than to papillary carcinomas dominated by papillae. This probably indicates a more active endocrine function rather than a different degree of malignancy. Papillary carcinomas, where follicular structures dominate, are therefore expected to respond to radioiodine treatment more favorably than those mainly forming papillae. Papillary carcinomas with abundant ground glass nuclei do not seem to have a lower volume density of heterochromatin than tumors lacking this nuclear feature. In the individual problem case with a follicular tumor, electron microscopy and morphometry cannot even distinguish between an adenoma and a well-differentiated follicular carcinoma.
Electron micrographs in five minutes.
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Papillary carcinomas of the thyroid have pore-deficient nuclei.
A significant reduction in nuclear pore density observed in papillary carcinomas compared to normal thyroid, adenomas and follicular carcinomas probably disturbs the nucleo-cytoplasmic transfer of ribonucleoproteins. This may contribute to the slow growth and indolent biological behavior of these tumors where even the presence of regional lymph node metastases does not worsen the prognosis. The signs of nuclear hyperactivity may result from an attempt to compensate for the nuclear membrane defect.
The pathology of experimental obstructive hydrocephalus. A scanning electron microscopic study.
Obstructive hydrocephalus was produced in 14-day old rabbits by injection of kaolin into the cisterna magna. The ependymal lining was studied by scanning electron microscopy. Marked hydrocephalus was present 1 or 2 weeks after the kaolin injection. The ependymal lining adapted remarkably well to the rapid expansion by increasing the surface area of the ependymal cells. No breaks or denudement of the ependymal lining was observed except at the sites of ruptured ventricular synechiae. Generally, these findings confirm previous light and electron microscopic observations on the same model (Torvik et al. 1976; Torvik and Stenwig 1977). The results are discussed in relation to current theories concerning the pathophysiology of acute hydrocephalus.
A new approach to low power photomicrography.
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