Radiosensitivity of subterranean bacteria in the Hungarian Upper Permian Siltstone Formation.

The main purpose of this work was to study the radioresistance of subterranean aerobic and anaerobic isolates from the Hungarian Upper Permian Siltstone (Aleurolite) Formation, in order to assess the safety of potential sites of future underground repositories for nuclear waste. A total of 93 isolates were studied. The radiosensitivities of these aerobic and anaerobic bacteria isolates were determined: the D10 values (decimal reducing doses) of the aerobic spore-formers lay in the range 0.80 -2.44 kGy, and those of the anaerobic spore-formers lay in the range 1.86 4.93 kGy. The D10 values of the aerobic and anaerobic vegetative isolates were much lower, in the ranges 0.11 0.57 and 0.22-0.40 kGy. respectively. The variability in bacterial radioresistance indicates the biodiversity at this potential disposal site. These results can affect the construction of a future underground repository, since knowledge of the most resistant microorganism may be of importance as concerns calculation of the time required to inactivate the bacteria surrounding the containers.

Characterization of subterranean bacteria in the Hungarian Upper Permian Siltstone (Aleurolite) Formation.

The main purpose of this work was to study the microbiology of the Hungarian Upper Permian Siltstone (Aleurolite) Formation, to assess the safety of future underground repositories for nuclear waste. Sixty-seven air, groundwater, technical water, rock, and surface samples were collected aseptically from different depths. The number of aerobic and anaerobic isolates was 277. The mesophilic minimum and maximum CFU counts of the air samples were 1.07-5.84 x 10(2).mL-1 (aerobic) and 0.22-1.04 x 10(2).mL-1 (anaerobic), respectively; those of the water samples were 0.39-1.25 x 10(5).mL-1 (aerobic) and 0.36-3.9 x 10(3).mL-1 (anaerobic); those of the technical water samples were 0.27-5.03 x 10(6).mL-1 (aerobic) and 4 x 10(5)-->10(6).mL-1 (anaerobic); and those of the aleurolite samples were 2.32 x 10(2)-2.47 x 10(5).g-1 (aerobic) and 0.45-9.5 x 10(2).g-1 (anaerobic). In the groundwater, the thermophilic aerobic bacteria count was 0-2.4 x 10(2).mL-1 and the thermophilic anaerobic bacteria count was 0.43-4.6 x 10(4).mL-1. The gases produced by the 16 gas-forming isolates were CO2 (aerobic isolates), and CO2 and H2 (anaerobic isolates). About 20% of the aerobic isolates produced siderophores. The proportions of organic acid producers were lowest in aerobic and anaerobic isolates from the aleurolite, 13% and 14%, respectively. The highest proportions of acid producers in the aerobic and anaerobic isolates from the air samples were 63% and 54%. Altogether 160 of the aerobic isolates and 52 of the anaerobic isolates were spore formers. The radiosensitivity of the aerobic isolates was also determined; the D10 values of the sporeformers ranged between 0.8-2.44 kGy. Our results indicate that the sulfate-reducing bacteria and the production of complexing agents (siderophores) may contribute to the mobilization of radionuclides from underground repositories. As well, microbial gas production can influence the environmental conditions. The variability in bacterial radiotolerance indicates the biodiversity at this potential disposal site. These facts must be considered during the planning of a nuclear waste repository.

Intrasellar hamartoma associated with pituitary adenoma.

The histological, ultrastructural and immunocytochemical features are reported of an intrasellar neuronal and lipomatous hamartoma associated with pituitary growth hormone (GH) cell adenoma and acromegaly. Electron microscopy demonstrated a close contact between neurons and adenomatous GH cells. By immunohistochemistry the adenoma cells revealed a positive staining for GH and prolactin. The neurons of hamartoma showed neurosecretory activity which might have induced the development of pituitary GH cell adenoma.

Radiation response of E. coli after combined treatment with misonidazole and WR-2721 at various oxygen concentrations.

It has been reported that the aminothiol compound WR-2721 is a promising radioprotective agent and in combination with misonidazole (MISO) seems to be of therapeutic benefit. Since the radiomodification is oxygen-dependent, the actual oxygen status of cells and the surrounding media is an important factor influencing their effectiveness. Escherichia coli B/r radioresponse was studied either alone or in combination with these compounds at various oxygen concentrations ranging from anoxia to high oxygen content. WR-2721 had a protective effect under anoxic conditions and gave overall protection when oxygen was present. The maximum protection was seen at 3.2% O2 in N2 (PF 2.08). In combination with MISO the hypoxic sensitization of MISO was completely abolished by WR-2721, resulting in radioprotection under hypoxic conditions as well. Under euoxic conditions MISO was able to reduce the protective effect of WR-2721 by about 21%. According to our results MISO and WR-2721 influence each other in their radiomodifying effect in either fixation or repair of the radiation-induced damage.

The role of water in the radiation sensitization of acetone.

These experiments were aimed at the better understanding of the mechanism of the enhancement of radiation damage brought about by acetone in spores of Bacillus megaterium. Particularly, the intention was to examine the extent of involvement of water content in this action of acetone. The radiosensitization of acetone increased with increasing oxygen concentration and ultimately became zero at 2.1% O2 in N2. The extent of sensitization increased with rising concentration of acetone up to the first peak (50% acetone in water) under anaerobic condition. Further increase in acetone concentration resulted a maximum response seen at 90% acetone in water. To investigate the role of hydroxyl radical in the radiation sensitization caused by acetone two different types of hydroxyl radical scavengers (t-butanol and iso-propanol) were used.

Flow-cytophotometry of nuclear DNA in biopsies of 45 human gliomas and after primary culture in vitro.

DNA distribution in biopsies and cell cultures of human gliomas was examined by flow-fluorescence-cytometry using ethidium bromide staining. Glioblastomas (n = 25) showed "polyploid", "marked tetraploid", or "hypertetraploid" aneuploid karyograms, comparable to subtypes previously proposed by Japanese authors. "Diploid-hyperdiploid" DNA patterns were manifest in 3 cases plus 1 sarcoma--glioblastoma, containing abundant rapidly growing mesenchymal cells. Most tumors showed S-phase increment. "Near-diploid" patterns could be a result of aggregated cells, and small 4 C peaks could be due to non-representative specimens (3 cases). During cultivation, the DNA distribution usually remained stable, but maxima occasionally shifted. Oligodendrogliomas (n = 11) and astrocytomas (n = 9) of low-grade showed low 4 c peaks. High-grade gliomas, however, showed abnormal DNA patterns. Thus, one case of an oligodendroglioma--I developed an abnormal "marked tetraploid" glioblastoma after a 3-year interval presenting its malignant transformation. DNA distribution can obviously vary during tumor evolution. However, it may well support the assessment of grading and more closely define the prognosis in gliomas.

Morphological investigations of mixed pituitary adenomas.

Thirteen pituitary adenomas were investigated by light and electron microscopy and in tissue culture. In all adenomas the production of growth hormone and prolactin was proved by endocrine symptoms of the patients and by laboratory tests. Histopathological findings were compared with culture characteristics. In 3 cases the adenoma consisted of three kinds of cell population, in 7 cases of two kinds, and in other 3 cases of one kind. In cases where 3 kinds of cell population were found, beside the granulated cells star-shaped forms without secretion granules could be observed. They probably corresponded to follicular cells. In three cases one single cell population was found. In these cases two different hormones might have been produced by one type of cell. These cells could be considered stem-like cellular elements or differentiated committed cells.

Light- and electron-microscopic features of an endocrinologically active pituitary adenoma cultured in vitro.

A pituitary adenoma from an acromegalic female patient has been studied in cell cultures. Two populations of parenchymal cells, i.e., elongated shapes and big pale forms with irregular outlines, were distinguished light-microscopically. Ultrastructurally, three types of cells were found. Two of them contained secretory granules in varying numbers and sizes. Based on the proportion of the various cellular elements these cells were considered as counterparts of the elongated shapes being responsible for the GH secretion at different rates. The third cell type with very few secretory granules was identified with the big pale forms. Presumably, they could be exhausted GH-secreting cells. Besides fine structural characterisation, cultured cells of endocrinologically active human pituitary adenomas offer suitable models for studying some phases of exocytosis and membrane retrieval.

Optic nerve gliomas. II. Cytological characteristics. Observations on cell and tissue cultures.

Cytological characteristics of optic nerve gliomas were studied parallel with histological structures in cell and tissue cultures. Histologically the tumours consisted of four different cell types: spindle-shaped elongated cells, round cells, stellate forms, and multinucleated cells. Dynamic properties of cultured optic glioma cells showed that stable cellular elements of the parent tissue arise from two fundamental populations, viz from elongated (piloid), and from round cells. Cells of both populations displayed a series of changes in the course of their cultures. A certain part of the slender elongated cells enlarged and became plump piloid cells of various shapes, or big stellate astrocytes. Giant multinucleated variants of these forms also emerged by fusion of the mononucleate forms. The round cells gradually turned into immature Astrocytes, and by a subsequent cell fusion they gave birth to big stellate cells. With the ageing of the cultures a polymorphous cellular picture developed which was mainly due to the active migratory and intracellular movement of the elongated and round cellular elements. Mitoses played a negligible role in this process. Several characteristics suggest that the round shapes are immature glia cells, and represent the least differentiated elements among all the cell components. The stellate and giant multinucleated forms might be considered as end-products of glia cell differentiation and they could originate both from the elongated and the round cells.

[Similarities between cultured human fetal glia cells and cell types from gliomas; cell culture studies]. / Emberi tenyésztett fetális gliasejtek és gliomákból származó sejttípusok közötti hasonlóságokról; sejttenyészetekben végzett vizsgálatok.

Authors carried out a comparative study of cell-cultures of human fetal brain tissue and gliomas of various histological structures. In 180-days long cultures of fetal brain tissue four types of cells could be distinguished: 1. large, polygonal cells, 2. small, round, immature glia-cells, 3. bipolar spongioblasts, 4. gliant astrocytes. These types of cells could not be identified with the cell types of adult human brain culture, but similar types of cells were found in cultures prepared of gliomas of different degree of malignancy. There is some evidence to suggest, that among these types of cells the most important are immature glial cells, since they seem to be multipotent and may play a part in the gliogenesis and in the formation of gliomas as well.

[Similarities between human fetal glia cells and glioma cell type in tissue cultures]. / Anlichkeiten zwischen menschlichen fetalen Gliazellen und Gliomzelltypen in Gewebekulturen.

Comparative studies were carried out on cell cultures of human fetal brain tissue and of gliomas of different tissue structures. In the cultures of fetal brain tissue maintained for 180 days, four cell-types could be distinguished: 1 large polygonal cells showing epithelial type growth; 2 groups of small round cells; 3 bipolar spongioblasts; and 4 giant astrocytes. The monolayers consisting of large cells formed a nursing layer for the small round cells and could be considered neuroepithelial cells. The small round cells forming groups were regarded as immature gliacytes which created migrational forms by means of active motion. The bipolar spongioblasts were considered a variant of the immature gliacytes. The giant astrocytes displayed the lowest plasticity; their appearance was interpreted as a true differentation and not simply as a change in form of one of the cell types. The cells of the fetal brain tissue could not be identified with the cells of the adult human brain. Still, all the four cell types appeared in the cultures of gliomas with different textures and different degrees of malignity. It seems that with respect to gliogenesis, among the four described cell types the immature gliacytes are of the greatest importance.

[Role of bacterial endotoxins in the tourniquet shock in rats]. / Die Rolle der bakteriellen Endotoxine beim Tourniquet-Schock der Ratte.

By means of the lead acetate endotoxin sensitising method it was possible to demonstrate the development of endotoxaemia in tourniquet ischaemia of rats. The lethality of shock was greatly reduced by retreatment with radio-detoxified endotoxin (Tolerin). Prelinary liquidation of the Gram-negative enceroflora caused a similar reduction of lethality. On the basis of the results endotoxaemia of intestinal origin triggered by the vasoactive substances liberated during ischaemia and reaching the circulation are considered of importance in the pathogenesis of tourniquet shock.

Primary lymphomas of the central nervous system; in vitro culture observations.

Out of 960 human brain neoplasms seven primary lymphomas were cultured and grown up to twenty eight days. The monolayers had common cytological characteristics; /i/ immediately after plantation a high density of uniform cells was observed; /ii/ many cells were lost during subsequent medium changes; /iii/ the monolayers contained lymphocyte-like cells in different numbers. According to their individual characteristics the cultures could be classified into three categories: 1./ In the cultures of three tumours lymphocyte-like cells predominated. These tumours had low proliferative capacity in vitro. 2./ Cultures of three other tumours consisting mainly of tissue macrophages had a high proliferative capacity in vitro. 3./ Cultures of a single tumour showed the combined features of the former two categories: both lymphocyte-like cells, and tissue macrophages were present. These cultures showed the highest proliferative activity. On the basis of these findings it is quite possible that beside other methods, tissue culture technique may be useful in the classification of brain lymphomas.