Search PubMed⌕ Search

Biomedical subjects

G Seifert

Publications and source records attributed to G Seifert.

At least 127 records · Page 7Linked to original sources
PubMed1985

[Adenocarcinoma of the salivary glands. The pathohistology and subclassification of 77 cases].

Seventy-seven adenocarcinomas of the salivary glands recorded in the Salivary Gland Register between 1965 and 1984 were analysed and classified histopathologically. The following results were obtained: 1. 2% of all salivary gland tumours and 10% of all malignant epithelial salivary gland tumours were allotted to the group of adenocarcinomas. The age peak lies in the 7th to 8th decade. 60% occurred in women, 58.5% were localized to the parotid gland, 28.5% to the minor salivary glands (palate, lips, and cheek), 11.5% to the submandibular gland and only 1.5% to the sublingual gland. 2. Solid, tubular and papillary adenocarcinomas can be distinguished. Additional criteria are microcysts, mucus production and grade of differentiation. 3. The solid adenocarcinoma (13%) is predominantly localized in the parotid gland and characterized by a low differentiation, invasive growth and metastases. 4. 62.5% of tubular adenocarcinomas (52%) are localized in the parotid gland, 27.5% to the minor salivary glands and 10% to the submandibular gland. Most of the tumours are highly differentiated. A distinct mucus production is present in 40% of the cases. Microcysts are very frequent. 5. Papillary adenocarcinomas (28.5%) are localized in almost 50% of cases to the minor salivary glands, 45% to the parotid and only 5% to the submandibular gland. Microcysts and mucus production can be observed in 50% of the cases. 6.5% of the cases have a mixed tubular papillary structure. 6. In differential diagnosis, thyroid gland carcinomas and metastases of other adenocarcinomas must be distinguished, the former by negative result of the thyroglobulin reaction, and absent mucus production. 7. Adenocarcinomas arise from the salivary duct system. Solid or tubular adenocarcinomas imitate stages of the embryonal development of the salivary ducts.

Adenocarcinoma↗
PubMed1984

Mast cells in cystadenolymphomas.

Cystadenolymphomas are a special kind of salivary gland tumours with an epithelial and a stromal part. Mast cells, which in this tumour were only rarely mentioned, were observed in large amounts in the stroma and in the epithelium. This type of cell is present especially in those cystadenolymphomas rich in epithelial parts. The possible significance of this observation is discussed.

Adenolymphoma↗
PubMed1984

Extraocular photoreceptors in the brain of Epilachna varivestis (Coleoptera, Coccinellidae).

Within the optic lobe of adult Mexican bean beetles, Epilachna varivestis, three complex areas were detected that display elements with the morphological appearance of photoreceptors. Each of these complexes contains about eight cells that show fully differentiated rhabdomeres, screening pigments and other features typical of photoreceptors. It was shown that these areas originate from larval stemmata, which move into the depth of the head capsule during metamorphosis and are finally embraced by the outgrowing optic lobes. Although the function of these formations is not yet known, there are some indications that they may play a role in the entrainment of circadian clocks.

Animals↗
PubMed1984

Reaction pattern of xenografted human salivary glands in nude mice. An immunohistological and autoradiographical study.

35 specimens of human parotid gland and 37 of submandibular gland were transplanted into athymic nude mice. At distinct time intervals, from 1 day to 8 months the transplants were collected and examined. The transplanted glands were studied by light microscopy, immunohistology and autoradiography. The following changes were detectable: acute injury to the xenograft and inflammatory reaction (day 1-7), regeneration of the transplant and the beginning of adaptation to the "mouse milieu" (day 8-30), completion of adaptation (day 30 and later). The presence of the following substances was analysed: amylase, lactoferrin, secretory component, tissue polypeptide antigen (TPA). Amylase was only detected in the early transplants. Lactoferrin was seen only in the small duct system. TPA was present during all transplantation periods and was quantitatively correlated with the 3H thymidine labeling index. From our observations we can say that the salivary glands show two different reacting compartments: a large and a small duct system. The histogenesis of the xenografts, and the relationships of the changes observed to human salivary gland diseases were discussed.

Amylases↗
PubMed1984

Immunoelectron microscopy of amylase in the human parotid gland. Ultrastructural localization by use of both the protein A-gold and the biotin-avidin-gold technique.

Specimens of the human parotid gland were studied by immuno-electron microscopy for the presence of amylase. Both the protein A-gold technique and the biotin-avidin-gold technique were used on the same specimens. Different fixations were tried. Amylase was detected in the zymogen granules in high amounts. This enzyme could even be seen in glutaraldehyde fixed and routinely embedded material. The subcellular localization of this enzyme opens a new field of functional morphological studies and studies in special tumours including acinic cell carcinomas.

Amylases↗
PubMed1984

Calcium redistribution, calcification and stone formation in the parotid gland during experimental stimulation and hypercalcaemia. Cytochemical and X-ray microanalytical investigations.

Distribution and redistribution of intra- and pericellular calcium was investigated in the parotid gland of rats under secretory stimulation and hypercalcaemia. The effects of hypercalcaemia and secretory stimulation and of the combination of both were compared. Calcium content was determined by atomic absorption spectrometry. Calcium distribution within the tissue was demonstrated by light microscopical ( GBHA ) staining and electron microscopical (pyroantimonate method) cytochemistry in combination with X-ray microanalysis. Typical calcium depot sites were the basal and cellular membranes, the calcium buffer organelles (i.e. mitochondria) the secretory granules and the acinar lumina. After stimulation (by isoprenalin ) a decrease of calcium-enriched secretory granules and a depletion of intracellular calcium buffer organelles occurred. During hypercalcaemia (induced by dihydrotachysterol), a calcium overloading of the cell membrane and intracellular buffer organelles without calcification was observed. Combined stimulation and hypercalcaemia induced an excessive calcium overloading of all intra- and extracellular calcium depots with excessive calcium release into the acinar lumina resulting in calcium phosphate aggregates and stone formation. Secretory stimulation and simultaneous hypercalcaemia exert potentiating effects on intracellular and intraluminal calcification proposing an importance for pathogenesis of human sialolithiasis.

Animals↗
PubMed1984

The embryonal carcinoma of the parotid gland. A rare example of an embryonal tumor.

Embryonal tumors are a neoplastic proliferation of cells of organ rudiments. Morphologically, these tumors are similar to the developmental stages of these organ rudiments. Embryonal tumors of the salivary glands have not been previously described. In the salivary gland register, reviewing the years 1965-1982 (n = 8043), we diagnosed 2,878 tumors of the salivary glands, of these 73 were tumors in children. One case was a malignant epithelial tumor in a 12-year-old boy, which showed the criteria of an embryonal carcinoma in light- and electron microscopy. The tumor revealed solid undifferentiated areas, epidermoid structures with keratinization and acinic structures. Immunhistochemically, the better differentiated epidermoid cells reacted positively with anti-CEA and anti-keratin, the acinic cells were positive with anti-amylase. The ultrastructure was characterized by primitive ductular epithelial cells and acinic cells with their typical morphological features. The embryonal carcinoma has to be distinguished from undifferentiated carcinomas of the salivary glands, which consist of primitive ductular structures only. The failure to detect other tumor markers (lactoferrin, tissue polypeptid antigen) indicates that poorly and well differentiated areas can exist simultaneously in embryonal carcinomas.

Child↗
PubMed1984

Adenolymphoma: an immunohistochemical study with monoclonal antibodies against lymphocyte antigens.

Twenty-two adenolymphomas (Warthin's tumours) were investigated with respect to their lymphoid stroma; 4 were analyzed by monoclonal antibodies against B-cells and T-cells. A slight predominance of B-cells was found. In the T-cell fraction, the T-helper cells outnumbered the T-suppressor cells by a factor of 4. These and other cell types were found in the stroma and in the epithelium. Mast cells were associated with those adenolymphomas having a high proportion of epithelium.

Adenolymphoma↗
PubMed1983

Amylase as an additional marker of salivary gland neoplasms. An immunoperoxidase study.

The presence of amylase in normal and neoplastic salivary gland tissue was investigated by immunoperoxidase techniques. Apart from normal and inflamed parotid glands, different kinds of tumours were studied with regard to amylase: acinic cell tumours, adenocarcinomas, adenoidcystic carcinomas, salivary duct carcinomas, mucoepidermoid tumours and squamous cell carcinomas. Amylase could be seen in acinic cell tumours, but not in other neoplasms. The results were discussed with respect to the diagnostic implications.

Adenocarcinoma↗
PubMed1983

Tumor markers in parotid gland carcinomas: immunohistochemical investigations.

Substances with "marker" characteristics for tumors were studied in parotid gland neoplasms. The substances included intermediate-sized filaments, oncofetal and proliferation antigens, metalloproteins, antigens related to the blood group system, and enzymes and other cellular products. The immunoperoxidase technique was applied on the following kind of tissues: normal parotid glands, Morbus Sjögren, cystadenolymphomas, pleomorphic adenomas, adenocarcinomas, adenoid cystic carcinomas, salivary duct carcinomas, mucoepidermoid tumors, squamous cell carcinomas, and anaplastic carcinomas. The intermediate-sized filaments of the prekeratin type were demonstrated in the ducts and myoepithelial cells of the normal parotid glands, and in the epithelial tumors, which all were vimentin negative. Carcinoembryonic antigen was found in squamous cell carcinomas and glandular differentiated tumors, whereas lactoferrin was detected only in a part of glandular tumors. Amylase was seen in acinic cell tumors.

Amylases↗
PubMed1983

Detection of tissue polypeptide antigen in salivary glands and salivary gland tumors. An immunohistochemical study.

Tissue polypeptide antigen (TPA) was analyzed immunohistochemically in parotid gland tissue. This antigen, which is generally regarded as a proliferative antigen, was detected in the ductal system of the normal parotid gland. Parotid gland tumors were analyzed as well: pleomorphic adenomas; cystadenolymphomas; adenoid cystic carcinomas, and mucoepidermoid tumors. TPA could be found in distinct parts of every kind of tumor. However, apart from the TPA-positive cells, negative cells could be observed. The implications of these investigations are discussed.

Adenolymphoma↗
PubMed1982

[Use of tumor markers in the diagnosis of salivary gland tumors].

The group of tumour markers contain antigens and cell products which can be demonstrated in tumour cells by immunocytochemical methods (immunofluorescence, immunoperoxidase) and can, thus, be analysed for the classification of tumour. In human salivary gland tumours the distribution of cytoplasmatic antigens as components of the cytoskeleton, the occurrence of cell membrane antigens and of enzymatic cell products is demonstrated. Prekeratin, as an intermediate-sized filament protein, is a specific marker of epithelial tumours, whereas vimentin is a marker of mesenchymal cells. A special feature is the occurrence of prekeratin and vimentin in spindle-shaped cells of pleomorphic adenomas. The tumour-associated carcinoembryonic antigen (CEA) is found in glandular tumours and highly differentiated keratinized squamous cell carcinomas. With regard to enzymatic cell products, lactoferrin is present in glandular tumours and amylase in acinic cell tumours, but lysozyme is not detectable. The implementation of tumour markers contributes not only to an improvement in tumour diagnosis, but opens up new aspects in the cyto- and histogenesis of tumours.

Amylases↗