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Biomedical subjects

S Falkmer

Publications and source records attributed to S Falkmer.

At least 127 records · Page 7Linked to original sources
PubMed1977

Microchemical assays of glutathione, zinc, cobalt and manganese in micro-dissected areas of the endocrine pancreas in the hagfish, Myxine glutinosa.

In hagfish islet parenchyma, consisting practically only of insulin-producing B-cells and agranular B-cell precursors, the contents of glutathione (GSH) and total protein-free thiols (NPSH) were determined on micro-dissected islet lobules. GSH was found to be of the same order of magnitude (22-25 mg/100 g wet weight) as in the islet parenchyma of a previously studied teleost fish and of some mammals, including man. However, the NPSH was found to be considerably higher in the islet lobules of the hagfish than in the teleostean islet parachyma. As in both teleost fish and mammals, GSH made up most of the NPSH in the hagfish erythrocytes, myocardium, and skeletal musculature. This discrepancy between hagfish islet parenchyma and other tissues indicates that the non-GSH portion of NPSH may be of particular significance for the insulin-producing B-cells. By means of flameless atomic absorption spectrophotometry the contents of zinc, cobalt, and manganese were determined in micro-dissected hagfish islet lobules. Neither zinc, nor cobalt, occurred in significantly higher concentrations in the islet parenchyma than in the liver or the skeletal musculature. Only manganese was found in somewhat higher amounts in the islet lobules than in the other tissues, but the contents were still low. The results indicate that none of the three heavy metals play any important role in the synthesis, storage, or release of insulin in the hagfish. The significance of this in relation to the prevailing hypotheses regarding the pathogenesis of alloxan diabetes is discussed.

Animals↗
PubMed1977

Some phylogenetical aspects on the occurrence of somatostatin in the gastro-entero pancreatic endocrine system. A histological and immunocytochemical study, combined with quantitative radioimmunological assays of tissue extracts.

Rodioimmunoassayable somatostatin (SRIF) was found in acid ethanol extracts from various parts of the gastro-entero-pancreatic (GEP) endocrine system in reptiles, amphibians, teleost bony fish, cartilaginous fish, and jawless fish, as well as in a deuterostomian invertebrate, the tunicate, Ciona intestinalis. The cellular sites could, as a rule, be easily visualized light-microscopically by the peroxidase-anti-peroxidase (PAP) immunocytochemical procedure, using guinea-pig and rabbit antisera against synthetic SRIF. The standard Hellerström-Hellman technique, used to detect argyrophi SRIF-storing D cells, failed to visualize the SRIF cells in teh GEP endocrine system of the tumicate and of the jaw-less fish. Moreover, the results comfirmed the previous description that this technique only exceptionally (and sometimes only after further modifications) gave positive results when applied to the GEP endocrine system of bony fish, amphibians, and reptiles. In cartilaginous fish, however, it worked adequately and confirmed the radio-immunological and immunocytochemical observations. In the mucosa of the alimentary tract and in the parenchyma of its associated glands of one echinoderm and two pelecypod molluscs and one crustacean arthropod no sgns of the occurrence of SRIF-storing cells were observed using the three correlated procedures. In several of these tissues, signs of the occurrence of insulin-producing cells had perviously been observed. Thus, SRIF seems to appear at a later evolutionary stage than insulin. The principal islets (Brockmann corpusles) of the marine teleost fish, Cottus scorpius, had the highest concentrations of radioimmunoassayable SRIF of all the GEP organs and tissues investigated, viz. about 200 ng/mg wet weight. Nevertheless, it was only 1/5 of the actual insulin content.

Animals↗
PubMed1977

Zinc and manganese contents of micro-dissected pancreatic islets of some rodents. A microchemical study in adult and newborn guinea pigs, rats, Chinese hamsters and spiny mice.

By a flameless atomic absorption spectrophotometry procedure, using a graphite furnace, it was possible to assay the contents of zinc and managanese in micro-dissected pancreatic islets of several rodents. Interest was focused upon the islets of guinea-pigs, due to the fact that guinea-pig insulin lacks a histidine residue in the B10 position of the molecule which normally binds zinc (or other heavy metals) in the hexamer formation, probably involved in the storage of insulin. Both the zinc and manganese contents were too low in the guinea-pig islet parenchyma to be reasonably involved in the storage of insulin in the beta-granules. Instead, it was suggested that guinea-pig insulin, like hagfish insulin, might crystallize without access to zinc or other heavy metals. Low zinc and manganese contents were also observed in newborn and diabetic guinea-pigs. The islet zinc content was high in the Wistar rat, the Chinese hamster, and the spiny mouse. No significant amounts of manganese were found in any of these kinds of islet parenchyma.

Animals↗
PubMed1976

Onto- and phylogenetical aspects on insulin-producing islet-cell tumors.

When onto- and phylogenetical aspects are taken into account when studying insulin-producing islet-cell tumors, it becomes clear that the recently discovered "type IV" islet parenchymal cells (or "delta 1" -cells) may play an important role in various states of hypoglycemia, both of neoplastic and non-neoplastic origin. Moreover, it becomes obvious that increased attention to this kind of islet cell through intensified light-microscopical, histochemical, ultrastructural and experimental investigations covering a wide range of animals, may help to clarify several unsolved problems in the cytological composition of the islets of Langerhans. The occurrence of islet-cell tumors (or hamartomas) in the most primitive vertebrate islet parenchyma known, viz. that of the hagfish, Myxine glutinosa, is reported, as well as an additional case of mixed carcinoid-islet-cell tumor in a human pancreas.

Adenoma, Islet Cell↗
PubMed1976

Scanning electron microscopy of the bronchial mucosa in some lung diseases using bronchoscopy specimens. A pilot study including cases of bronchial carcinoma, sarcoidosis, silicosis and tuberculosis.

In order to study the lung defence mechanisms and the mucociliary transport system scanning electron microscopy was performed on biopsy specimens obtained at bronchoscopy under local anaesthesia. There were great variations in the appearance of the cilitated epithelium from the large bronchi in 40 patients with bronchial carcinoma, sarcoidosis, silicosis, tuberculosis and other lung diseases. Areas with a low frequency of cilia were observed mainly in granulomatous disorders, and in silicosis, atypical cilia occurred abundantly. Squamous metaplasia with a complete loss of cilia was found in chronic bronchitis, bronchial carcinoma, after radiotherapy and in two of seven cases of sarcoidosis. Scanning electron microscopy seems to be an excellent method for studying the surface of the bronchial epithelium in many lung diseases, and may prove to be helpful in occupational medicine.

Adult↗
PubMed1975

Persistent neonatal hypoglycaemia. A clinical and histopathological study of three cases treated with diazoxide and subtotal pancreatectomy.

Two boys and one girl developed persisting hypoglycaemia 12, 24, and 48 hours after birth. Although there was no known history of hereditary diabetes mellitus, the birth weight was high in two cases, and some additional traits of foetopathia diabetica could not be excluded clinically. All had high serum insulin levels with frank hyperinsulinaemia in one case. Glucose tolerance tests also indicated hyperinsulinism. Diazoxide (8 to 27 mg/kg) elevated the blood glucose levels, but did not prevent severe hypoglycaemic episodes. The effects of subtotal pancreatectomy were only transient. The patients have now been kept on permanent diazoxide therapy for 2-4 years at dosages slightly lower than those used before operation. No islet-cell tumour was found at the subtotal pancreatectomy. In all 3 cases, the pancreatic islets were markedly hyperplastic and of irregular shape with the occurrence of large B-cells with giant hyperchromatic nuclei and chromophobe "agranular" or sparsely granulated cells. The predominating kind of islet cells showed tinctorial features of A2-cells but--in the absence of available material set aside for ultrastructural analysis--it could not be settled whether this was a result of a proliferation of A2-cells only or of "type IV cells" as well. Against the background of previously published reports, the present cases serve to illustrate that additional accuracy of diagnosis and classification of neonatal persistent hypoglycaemia requires quantitative information about the structural changes in the pancreatic islet cells, and that this can be obtained from conventional biopsy specimens.

Biopsy↗