Vergleichende elektronenmikroskopische Untersuchungen normaler menschlicher Pankreasinseln und eines hormonell-aktiven Inselzell-Carcinoms mit Hyperinsulinismus

Georgsson, Guðmundur; Wessel, W.

doi:10.1007/bf00571743

Cited by 13 publications

(3 citation statements)

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“…Therefore, it has been concluded that hyperinsnlinism in patients with an insulinoma is not due to an excessive production of insulin but to an inability to control its storage and release [12,34]. Reports about ultrastruetural investigations of insulinomas are usually confined to single or few cases [3,14,20,21,25,26,28,41] and, therefore, do not give sufficient information about the broad scale from nearly normal B-cells [3,21,25,26,28] to atypical cells [3,14,20] and the frequency in which they occur in different insulinomas. Of special interest is the correlation of the histology and ultrastrnctm'e of insulinomas with the insulin content of the tissue; this i The expression "insulinoma" is used throughout this article instead of "insulin-producing islet tumour" or "insulin-producing insulinoma" or "insulin-producing pancreatic tumour".…”

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confidence: 99%

Biochemical and morphological investigations of 30 human insulinomas

et al. 1973

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Thirty human insulinomas have been investigated histologically and their immunoreaetive insulin (IRI) content estimated. In most eases immunohistological and ultrastruetural studies were also performed and the percentage of proinsulin-like components (PLC) in the tumour determined. Except for 1 ease the II~I concentration in the tumours was lower (0.01-89.0 U/g) than in the islet tissue. Histologically, immunohistologically and ultrastrueturally a variable number of tumour cells contained few and often no beta-granules, indicating a decreased storage capacity for insulin. This defective storage capacity seems to be the major functional abnormality of insulinoma cells. Ultrastrueturally four types of insulinoma can be distinguished. The ultrastructural diagnosis of an insulinoma can only be made in t?~e I (typicai beta-granules, 13 cases) and type II (typieM and at~2pical granules, 7 eases) but, not in type III (atypical granules only, 4 eases) and type IV (virtually agranular, 4 eases). The type IV tumours had the lowest IRI concentration and did not respond to diazoxide treat-merit. The IRI concentration of the uninvolved pancreas of 19 patients was 2.0~0.2 U/g and in the range of nondiabetic adults.-The percentage PLC in 19 insulinomas was higher (5.3-22%) than in the pancreas of human adults with and without insulinoma (1.7-4.8%). The percentage of PLC in the serum of patients with insulinoma was always higher than in their tumours (33-61%). It is suggested that the higher PLC levels found in the tumour and serum of insulinoma patients are the consequence of the reduced storage capacity of the tumour cells resulting in a rapid passage through the granular route or even a non-granular release of newly synthesized insulin.

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confidence: 99%

Biochemical and morphological investigations of 30 human insulinomas

et al. 1973

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“…Electron microscopic findings: T h e tumor cells of both types were relatively rich in cytoplasmic organelles (Figs,3,8). Mitochondria were abundant in number, relatively large but varied in size, and oval or spherical in shape.…”

Section: Resultsmentioning

confidence: 98%

Ultrastructure of functioning beta cell tumors of the pancreatic islets

Suzuki

Matsuyama

1971

Cancer

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Eight cases of functioning beta cell tumors with recurrent hypoglycemia, including 3 with metastases, were studied by electron microscopy. Based on their ultrastructure, the tumors were classified into 2 types. Type 1 was composed of cells with abundant typical beta granules which showed a close resemblance to the non‐neoplastic beta cells of the pancreatic islets. Type 2 consisted mainly of cells without the typical granules, intermingling with a small number of cells which revealed a few, immature beta granules. Numerous dense granules resembling lysosomes were found in the majority of the cells. The cells of this type possessed extensive interdigitation of the cell membrane forming the intercellular spaces. Sometimes intracellular canaliculi were also found. Thus, it was demonstrated that the cells of type 2 tumors had morphological similarities to the cells of the terminal ductules of the pancreas. These results tend to suggest that the ultrastructure, including the formation of the secretory granules, reflects the stages of differentiation of the tumor cells.

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“…Most tumor cells had abundant mitochondria and rough-and smooth-surfaced endoplasmic reticulum frequently forming conspicuous vesicles and sometimes showing cysternal dilatation and well-developed Golgi apparati (Figs. 6,7,8). Development of these cell organelles was most prominent in the tumor cells for Case 1.…”

Section: Electron Microscopymentioning

confidence: 88%

Histology, ultrastructure, and tissue culture of human insulinomas

Akagi

Fujii

1981

Cancer

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Four cases of insulinoma were studied by electron microscopy. Insulinoma cells were also cultured in vitro. Ultrastructure was correlated with the content of immunoreactive insulin (IRI) and the percentage of proinsulin-like component (PLC) in the serum, tumors, and culture fluid. The number and shape of secretory granules varied amont the samples, from the tumors having typical beta granules to poorly granulated tumors having a few atypical granules. High levels of IRI in the serum and a high percentage of PLC in the serum and tumor, found in a patient with a virtually agranular tumor, combined with the fact of rare occurrence of emiocytosis, suggest a defective insulin storage mechanism and alternative routes of insulin release in insulinoma cells.

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Vergleichende elektronenmikroskopische Untersuchungen normaler menschlicher Pankreasinseln und eines hormonell-aktiven Inselzell-Carcinoms mit Hyperinsulinismus

Cited by 13 publications

References 13 publications

Biochemical and morphological investigations of 30 human insulinomas

Biochemical and morphological investigations of 30 human insulinomas

Ultrastructure of functioning beta cell tumors of the pancreatic islets

Histology, ultrastructure, and tissue culture of human insulinomas

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