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Biomedical subjects

U Askensten

Publications and source records attributed to U Askensten.

22 records · Page 2Linked to original sources
PubMed1987

Electronmicroscopical, immunohistochemical, immunocytochemical and biological evidence for the occurrence of cardiac hormones (ANP/CDD) in chondrichthyes.

As representatives of the vertebrate class of chondrichthyes the plagostomian species Squalus acanthias, Scyliorhinus canicula and Raja clavata as well as the holocephalan species Chimaera monstrosa were investigated for the presence of cardiac hormones of the atrial natriuretic polypeptide/cardiodilatin- (ANP/CDD-) family. ANP/CDD-immunoreactive cells were detected in the atria and the ventricles of all species studied. While these cells failed to react with antisera raised against the N-terminus of CDD-126 (= gamma-ANP) they reacted with all antisera directed against sequences of the C-terminus of CDD-126 (CDD 99-126) which is identical to alpha-ANP. The ANP/CDD-immunoreactive cells were found in high numbers in all regions of the atria and in moderate density also in the ventricles. In correspondence, in the electron microscope, myoendocrine cells which were characterized by dense-cored secretory granules were identified in the atrial and ventricular myocardium. With the use of the protein A-gold technique, ANP/CDD-immunoreactivity was determined within the secretory granules. Furthermore, in the bioassay, prepurified extracts of the atria and the ventricles of Scyliorhinus and Chimaera exerted dose-dependent relaxations of the pre-contracted mammalian (rabbit) aorta. In both cases the atrial extracts proved to be more potent than the ventricular extracts. The present findings indicate that myoendocrine cells occur in the atria and ventricles of chondrichthyes and that these cells contain homologous cardiac hormones of the ANP/CDD-family in their secretory granules. The results are compared with those obtained earlier for the other vertebrate classes and their phylogenetic and functional significance is discussed.

Animals↗
PubMed1987

Comparison between slide and flow cytophotometric DNA measurements in breast tumors.

Nuclear DNA analysis was performed in 37 human mammary adenocarcinomas in order to elucidate the difficulties and pitfalls connected with the interpretation of DNA histograms obtained using different methodologic approaches. For each tumor, DNA profiles were obtained by means of slide microspectrophotometry on a fine needle aspirate, slide cytophotometry on a 4-micron histologic section and flow cytometry on a suspension prepared from a cube of fresh tissue. When the DNA histograms were interpreted according to criteria usually applied to discriminate low-grade malignant tumors from high-grade malignant tumors, some tumors classified as euploid by one method were classified as aneuploid by another method. The main reasons for this weak correlation seem to be in specimen preparation and in tumor cell representation within the specimen between the methods. Another reason is that slide and flow techniques exhibit different sensitivities for malignancy-associated nuclear DNA changes: minor alterations of the DNA content of the tumor stemlines seem to be more exactly reported by means of the flow technique whereas structural alterations of the nuclear chromatin seem to be more sensitively recorded by means of the slide technique. It is suggested that thorough control of each step of the various DNA analysis procedures and the use of information obtainable by slide and flow techniques taken together may significantly improve the prognostic value of DNA measurements.

Adenocarcinoma↗
PubMedDate not supplied

Cytochemical assessments of the nuclear DNA distribution pattern by means of image and flow cytometry in thyroid neoplasms and in non-neoplastic thyroid lesions. A comparative methodological study.

The two most prevalent techniques for cytochemical DNA assessment of the nuclear DNA distribution pattern in neoplastic cells are image cytometry (ICM) and flow cytometry (FCM). The aim of the present study was to compare the results of nuclear DNA assessments, obtained by means of these two methods, in fresh surgical biopsy specimens from the thyroid gland, both in neoplasms and in nonneoplastic lesions. Material for DNA analysis was taken preoperatively by fine needle aspiration (FNA) biopsy from 13 papillary thyroid carcinomas and analyzed by the two methods. Surgical specimens were taken from 48 papillary thyroid carcinomas (one of which showed low differentiated papillary and anaplastic giant cell formations at autopsy), 2 follicular carcinomas, 66 follicular adenomas, 7 medullary carcinomas as well as from the nodules of 17 non-toxic colloid goitres and 19 specimens from the diffusely hyperplastic thyroid parenchyma in patients with hyperthyroidism. For the ICM assessments, FNA biopsies or imprints were made from the macroscopically identified fresh thyroid biopsy specimens; for the FCM assessments FNA specimens from the same region were used. In 155 out of the 159 specimens the results obtained by means of the two methods were the same. The DNA distribution pattern in 106 of the neoplasms and in all the 36 non-neoplastic lesions were of the "euploid" type (i.e. "diploid" or diploid/tetraploid"), whereas that of 17 neoplasms were of the "aneuploid" type. Fifteen of the histopathologically benign follicular adenomas showed a cytochemical DNA distribution pattern that by means of FCM was of the "aneuploid" type.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗