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F Ramelli

Publications and source records attributed to F Ramelli.

10 recordsLinked to original sources
PubMed1987

A disproportionate accumulation of fibrous tissue is not a causal factor in human goitre growth.

Histological preparations from human nodular goitres reveal the presence of variable and sometimes considerable amounts of acellular material separating the individual follicles. Part of this interstitial tissue consists histologically of fibrous strands. However, quantitative data on the fibrous tissue content of goitres are scarce. In the present study the proportion of fibrous tissue in normal human thyroids and human goitres was determined biochemically by measuring their content of collagen, the predominant component of fibrous tissue. Total collagen content increased in parallel to thyroid weight. The relative collagen content, however, decreased slightly but significantly with increasing thyroid weight. The collagen/DNA ratio (= fibrous tissue/cell number ratio) was not higher in goitres than in normal human thyroids. These results indicate that in goitre growth, there is no disproportionate accumulation of fibrous tissue accompanying the multiplication of thyroid follicular cells. They are in line with the earlier findings that despite histological heterogeneity, the main component of nodular goitres is newly generated follicles.

Age Factors↗
PubMed1983

[Autonomy and heterogeneity of the follicle in euthyroid and hyperthyroid human nodular goiter: answer to old riddles?].

The mechanisms responsible for the transformation of a morphologically and functionally normal thyroid into a heterogeneous eu- or hyperthyroid nodular goitre are summarized. The 3 basic processes of goitre pathogenesis are: 1. Each goitre develops from a normal thyroid gland by generation of new follicles. 2. New follicles are formed by multiplication of preferentially replicating cell clones of the follicular epithelium. Follicles already begin multiplying in response to a goitrogenic stimulus too weak to enhance metabolic functions other than replication. 3. The epithelial cells of normal follicles are not homogeneous and monoclonal, but belong to different populations with different metabolic equipment. Therefore, the daughter follicles may be metabolically different, e.g. in iodinating capacity. A certain degree of autonomous, i.e. TSH-dependent function is inborn to all follicles. The individual degree of autonomy of iodine turnover is not variable during goitrogenesis but determined by the metabolic individuality of the mother cell at the moment of folliculoneogenesis. These three basic processes explain the typical heterogeneity of nodular goitre. From autonomous highly iodinating cell families, autonomous "hot" daughter follicles arise which may be scattered all over the gland either as single follicles or as clusters of varying size (so-called "disseminated autonomy"). Particularly large clusters of "hot" follicles result in scintigraphically visible hot nodules, often called "toxic adenomas". Hyperthyroidism appears when the total joint autonomous hormone production of normal and "hot" follicles exceeds the requirements of the organism. The large majority of goitre nodules, including the so-called "toxic adenoma", are not true monoclonal benign neoplasias. Rather, they are built up by the same polyclonal heterogeneous follicles as extranodular goitre tissue. They have no choice but to expand in nodular fashion because they replicate within a poorly extensible network of connective tissue. This network of fibrous tissue results from scarring of multiple hemorrhagic necrosis occurring episodically during goitre growth.

Adult↗
PubMed1983

The site of leakage of intrafollicular thyroglobulin into the blood stream in simple human goiter.

Serum thyroglobulin is increased in many thyroid diseases, including simple goiter. We followed thyroglobulin levels in 19 patients with diffuse and nodular euthyroid goiters by serial measurements of 80 samples over 2 yr. The large intraindividual variations suggested episodic release of thyroglobulin in this thyroid disease. To test the hypothesis that the phenomenon was due to sporadic release of colloid from diseased follicles, we studied 98 multinodular goiters by conventional histological techniques. Sixty-four surgical samples were auto-radiographed. Focal necrosis of single follicles as well as large necrotic areas, involving multiple follicles together with interstitial stroma, were found in 42% of the goiter specimens. The earliest stage of necrosis was focal death of epithelial cells, often followed by hemorrhages. Through the epithelial gaps, colloid leaked out into the interstitial space. In later stages, granulation tissue containing numerous macrophages invaded damaged follicles. Fibrous scars remained as ultimate witness of repair processes. In one chance observation, acute release of highly labeled thyroglobulin from follicular lumina into the interfollicular interstitium was autoradiographically documented. We conclude that the varying concentrations of thyroglobulin in serum of patients with simple goiter may result from episodic necrosis of follicles, permitting leakage of colloid into the interfollicular space.

Epithelium↗
PubMed1982

Pathogenesis of thyroid nodules in multinodular goiter.

Pathogenesis of nodule formation was studied in over 100 nodular goiters from a subendemic area. 60 surgical specimens were autoradiographed. Only one classical, well-encapsulated adenoma was detected. All other nodules were incompletely encapsulated and consisted of follicles that were morphologically and functionally identical to those of nonnodular parenchyma. Most characteristic was the tremendous interfollicular heterogeneity appearing on autoradiographs. Nodular goiters contain multiple foci and strands of fibrous tissue, which result from scarring of multiple hemorrhagic necroses occurring during goiter growth. Therefore, the slowly growing number of newly formed follicles has to squeeze into the meshes of an inelastic network of connective tissue. Nodular growth pattern is the inevitable consequence. Some particular nodules expand because of excessive accumulation of colloid. We conclude that most thyroid nodules in long-standing goiters consist of ordinary, polyclonal goiter follicles which expand in nodular fashion because they replicate within a mold made out of a poorly extensible network of connective tissue.

Autoradiography↗
PubMed1979

[Treatment of hyperlipidemia type II with soybeans].

15 outpatients with type II hyperlipoproteinemia (7 with type IIa and 8 with type IIb) were treated with soybean. This diet induced a significant decrease of plasma cholesterol levels from 314 +/- 24 to 267 +/- 30 mg/100 ml. Triglycerides levels remained unchanged. LDL-cholesterol decreased significantly from 241 +/- 26 to 194 +/- 32 mg/100 ml, whereas HDL-cholesterol increased only slightly and not significantly from 38 +/- 7 to 40 +/- 8 mg/100 ml. In our efforts to reduce hyperlipidemia the very low cost of these vegetable proteins is a further advantage. The hypocholesterolemic mechanism of soybean diet is unknown.

Cholesterol↗