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Biomedical subjects

M Matejka

Publications and source records attributed to M Matejka.

At least 55 records · Page 3Linked to original sources
PubMed1987

Increased plasma-6-oxo-PGF1-alpha but normal PGI2 half-life in patients with maxillo-facial tumors.

In 56 patients with histologically verified maxillo-facial cancer the plasma 6-oxo-PGF1-alpha was determined prior surgery using a specific RIA and the double antibody technique. Furthermore, the half-life of synthetic PGI2 has been assessed via the disappearance curve of biological activity on platelet aggregation inhibition. Part of the patients has been monitored by the same test different time intervals after radical surgery. Normal values of 6-oxo-PGF1-alpha amount below 1 pg/ml. - normal half-life of PGI2 in plasma in-vitro about 10 minutes. Prior surgery a significantly increased 6-oxo-PGF1-alpha can be seen, whereas the PGI2 half-life is unaffected. In patients without local or general recurrence normal 6-oxo-PGF1-alpha levels are monitored. No change occurred in the half-life of PGI2. These findings underline the additive value of 6-oxo-PGF1-alpha as a tumor marker. The data do not support the view presented earlier, that a change in plasmatic PGI2 half-life might favour the onset and the extent of recurrence at least in patients suffering on maxillo-facial cancer.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Modulation of NK activity in regional lymph nodes by preoperative immunotherapy with OK-432 in patients with cancer of the oral cavity.

The influence of preoperative perilesional therapy with the potent bacterial biological response modifier (BRM) OK-432 on natural killer (NK) cell activity in peripheral blood and tumor draining lymph nodes (LNs) of patients with head and neck cancer (HNC) has been investigated. Pretreatment NK activity in peripheral blood (PB) was comparable within the group of HNC patients. However, after perilesional OK-432 therapy, a significant increase in cytotoxicity was observed by day 8. Furthermore, postoperative suppression of PB NK activity was less pronounced in patients with OK-432 therapy. In tumor draining LNs, NK activity was significantly higher in patients receiving OK-432 therapy than in those treated by surgery alone. No differences were detected concerning the in vitro stimulatory capacity of interferon (IFN) and/or Staphylococcus protein A (SPA) on LN NK activity in both the OK-432 treated and untreated group. Furthermore, by immunoperoxidase technique, LNs of OK-432 treated patients were found to express a higher number of cells reacting with the monoclonal antibody HNK-1 compared to LNs of the untreated group. Both these results suggest that perilesional OK-432 therapy leads to an increase in number and function of NK cells in regional LNs, together with an increase in NK activity in PB in some but not all patients.

Adult↗
PubMed1986

Immunohistochemical detection of 6-oxo-PGF1 alpha and PGE2 in radicular cysts.

Prostaglandin synthesis in the wall of radicular cysts was determined by immunohistochemistry and radiothinlayer chromatography. PGE2 is predominantly produced by plasma cells and histiocytic elements, whereas much less is synthesized by fibroblasts and endothelial cells as estimated using immunohistochemistry. 6-oxo-PGF1 alpha, however, was primarily found to be generated by endothelial cells and fibroblasts; only small amounts seem to be derived from histiocytic elements and plasma cells. The response of the cystic epithelium to anti-PGE2 and anti-6-oxo-PGF1 alpha antibodies was negative or showed only minimal staining. It can thus be concluded that the granulation tissue and its cellular components modulating the inflammatory process are the main source of prostaglandin synthesis in the wall of radicular cysts and may therefore be responsible for the resultant osteolytic activity.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Organisation of experimental thrombosis by blood cells. Evidence of the transformation of mononuclear cells into myofibroblasts and endothelial cells.

To clarify whether thrombus organisation was carried out by local cell activity or by elements of the circulating blood we developed an artificial prosthesis, made of an impermeable polyurethane material with an athrombogenic surface but with a central part consisting of a DACRON velour ring which was thrombogenic. We implanted these devices into the aorta of 10 sheep. In these animals, organisation of the central thrombus by local aortic cells could be excluded. After varying periods of time (2-84 days), the device was removed and the organized thrombus investigated by light and electron microscopy. From our investigations the organisation process with the development of mesenchymal cellular elements proceeded in 3 steps: The activation of the mononuclear macrophage system, the appearance of myofibroblastic cells and endothelial formation. The activation of the mononuclear macrophage system is probably induced by chemospecific products of metabolism arising from aging thrombotic material. Apart from mononuclear elements such as monocytes, macrophages, and giant cells we observed fibroblast-like and myofibroblast-like cells. The matrix contained collagen. Endothelium developed on the surface of the organizing thrombus. The final stage was characterized by the formation of a pseudovessel wall, which followed the pattern of the vascular model. Our findings support the hypothesis that a thrombus may be organized by cells derived from the circulating blood.

Animals↗
PubMed1985

Prostaglandin synthesis in dental cysts.

The synthesis of prostaglandins by dental squamous cell cysts was studied. Radiothinlayer-chromatography (RTLC) showed C14-labelled arachidonic acid to be converted into the prostaglandins PGE2, 6-oxo-PGF1 alpha, PGF2 alpha and PDG2. In addition, hydroxyfatty acid synthesis in excess of total prostaglandin production was observed. The substances mentioned are thought to be causally involved in the osteolytic activity of dental cysts.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Evidence that PGI2-generation in human dental cysts is stimulated by leucotrienes C4 and D4.

Various prostaglandins, particularly PGE2 and PGI2, appear to play a major role in osteolytic processes. The bone-destructive action of dental squamous cell cysts is thought to be caused or at least mediated by prostaglandins. Both leucotrienes and prostaglandins are synthesized from a common precursor substance, i.e. arachidonic acid, in a series of reactions. There is a special relation between leucotrienes and PGI2 in that PGI2 synthesis in endothelial cells can be enhanced by LTC4 and LTD4. R-TLC showed conversion of the arachidonic acid added into PGI2 in 8 out of 12 cases, as reflected by the stable degradation product 6-oxo-PGF1 alpha. In 8 cases bioassay showed PGI2 synthesis without addition of LTC4 and LTD4. Incremental LTC4 and LTD4 additions were found to cause a highly significant increase of PGI2 synthesis rates. In summary, LTC4 and LTD4 stimulate PGI2 synthesis in chronic inflammatory processes in vivo and may thus elicit or accelerate osteolysis.

Arachidonic Acids↗
PubMed1984

[Scintigraphy using 111-indium-oxine-sulfate-labeled autologous granulocytes compared to scintigraphy using 99-Tc-pyrophosphate in inflammations of the jaw region].

The present paper compares scintigraphy using leucocytes labelled with 111 indium oxine sulphate with conventional 99Tc pyrophosphate scintigraphy for the investigation of inflammatory processes in the region of the jaw bones. It also tries to establish whether progress can be made in the field of differential diagnosis using a combination of these two methods of investigation. It is shown that conventional scintigraphy using 99Tc pyrophosphate represents an approved method of investigation, whereas scintigraphy using autologous leucocytes does not as yet fulfil the expectations that have been placed in it.

Abscess↗
PubMed1984

The cyclo-oxygenase and lipoxygenase pathways in human oral cancer tissue.

This paper reports on the synthesis of prostaglandins in oral squamous epithelial carcinomas. Using radio-thin-layer chromatography, we observed the conversion of 14C-labelled arachidonic acid into the prostaglandins PGE2, PGF2 alpha, PGI2 and PGD2. We also observed an approximately equal production of hydroxy fatty acids. The role of the above-mentioned substances in the growth of malignant tumours and the process of metastasis is discussed.

Adult↗
PubMed1983

Epidermal Langerhans cells in mycosis fungoides and Sézary syndrome.

The purpose of the study was to examine whether apposition between epidermal Langerhans cells and atypical lymphoid cells is a constant finding in mycosis fungoides (MF) and whether it also occurs in the Sézary syndrome (SS). Biopsies of 8 patients with MF and 2 patients with SS were examined by transmission electron microscopy. In both cases of SS and in 7 cases of MF appositions between the 2 types of cells were observed. The appositions were less frequently seen in stage III MF lesions than in MF stage II. The cell membranes of the Langerhans cells and the apposed atypical lymphoid cells formed gap junction-like structures in several instances. Our results indicate that the phenomenon of cellular interaction between epidermal Langerhans cells and atypical lymphoid cells is a constant finding in cutaneous T-cell lymphomas.

Aged↗