Giant visible and infrared light attenuation effect in nanostructured narrow-bandgap glasses.

A unique effect of Bi on the optical and electrical properties of mixed Ga-containing Ge-Se and Ge-Te glasses is discovered. It is shown that glass with a low Bi content is completely transparent in a 3-16 µm spectral range, while the glass with a slightly higher Bi content possesses a large (>10 db/mm) attenuation coefficient, making a ∼millimeter thick glass sample fully opaque to VIS-IR radiation. Despite this contrast, both types of glass are found to retain their semiconducting properties, the DC conductivity at room temperature, σDC∼10-3 S/m, being comparable to that of silicon.

Nanoscale Inhomogeneities Mapping in Ga-Modified Arsenic Selenide Glasses.

Nanoscale inhomogeneities mapping in Ga-modified As2Se3 glass was utilized exploring possibilities of nanoindentation technique using a Berkovitch-type diamond tip. Structural inhomogeneities were detected in Gax(As0.40Se0.60)100-x alloys with more than 3 at.% of Ga. The appeared Ga2Se3 nanocrystallites were visualized in Ga-modified arsenic selenide glasses using scanning and transmission electron microscopy. The Ga additions are shown to increase nanohardness and Young's modulus, this effect attaining an obvious bifurcation trend in crystallization-decomposed Ga5(As0.40Se0.60)95 alloy.

Protection of L5178Y cells by vitamin E against acute hydroxyurea toxicity does not change the efficiency of ribonucleotide reductase-mediated hydroxyurea-induced cytotoxic events.

Exposure of L5178Y cells in culture to 0.2 mM hydroxyurea (HU) for up to 48 h induces inhibition of DNA synthesis, killing of about 20% of cells during the first 24 h exposure, gradual progress of cells into the state of unbalanced growth (measured as progressive increase in cell size, DNA protein ratio and acid phosphatase activity) with final death of the majority of cells. These effects were used to compare effectiveness of rapid and late HU cytotoxicity in cells treated with HU in the presence or absence of vitamin E, employed as a protective agent against non-specific toxicity of HU. It has been found that while the presence of vitamin E prevents cell killing induced by HU treatment during first 24 h, its presence does not change the progress of cells into the state of unbalanced growth and final cell killing. It is suggested that the protection exerted by vitamin E against HU-induced side toxicity does not change the effectiveness of ribonucleotide reductase-mediated DNA synthesis inhibition, leading to cell death through the state of unbalanced growth.

Early hepatic changes in rats induced by permethrin in comparison with DDT.

In this study permethrin [(3-phenoxyphenyl)-methyl-3-(2,2-dichloroethenyl)-2,2-dim ethylcyclopropanecarboxylate] and DDT [1,1-(2,2,2 trichloroethylidene)-bis-(4-chlorobenzene)] were compared in rats for their effects on early hepatic changes, proposed in the literature to be useful endpoints in screening for non-genotoxic hepatocarcinogenesis and/or liver tumour promotion. We compared the effects of both insecticides on the following endpoints: hepatomegaly, mitogenesis (DNA synthesis, mitotic activity, percentage of binuclear cells) and liver pathology. Male Wistar rats received permethrin (PERM) or DDT in one, three, five and 14 daily oral doses (at 24-h intervals) equivalent to 1/10 LD50. Distinct differences in early liver response between PERM and DDT were observed. DDT stimulated the early effect consisting of hepatomegaly accompanied by an increase in hepatocellular proliferation with signs of cell necrosis. Thus, it might be concluded, that the mitogenic effect of DDT was at least partly related to a regenerative liver response. Although PERM significantly affected DNA synthesis and increased binuclear hepatocytes, this compound did not increase the number of mitotic figures. These results suggest that PERM may inhibit of phase G2 in the cell cycle and consequently it may suppress the cell entering into the stage of mitosis (M-phase). In addition, the present findings provide evidence for the occurrence of abnormal mitoses in the hepatocytes of rats treated with DDT.

Studies of early hepatocellular proliferation and peroxisomal proliferation in Wistar rats treated with herbicide diclofop.

A study was performed to determine whether diclofop (2-(4-(2,4-dichlorophenoxy) phenoxy)propionic acid), introduced as a herbicide, exhibits the properties of peroxisome proliferators (PPs). Diclofop was administered orally at 7-56 mg/kg body weight per day to male Wistar rats for 2, 4, 7 or 14 consecutive days and some effects regarded as early hepatic markers of PPs were studied. The early changes in rat liver, produced by short-term treatment with diclofop consisted of mitogenesis and, time- and dose-related increase in liver weight. Hepatomegaly was typically associated with proliferation of smooth endoplasmic reticulum (SER) and peroxisomes. The parallel biochemical measurements showed that there was a dose-dependent increase in peroxisomal palmitoyl-CoA oxidation and catalase activity in treated rats. Markers of hepatocellular proliferation (S- and M-phase) indicated that mitogenesis was transient and declined despite continuation of diclofop treatment. The threshold exposure level for the palmitoyl-CoA oxidation (one of the peroxisome proliferation markers) was approximately the same (14 mg/kg body weightxper day) as for the stimulation of mitogenesis in Wistar rats. However, for hepatomegaly and catalase activity the threshold exposure level was 7 mg/kg body weightxper day. The results presented here demonstrate clearly that diclofop belongs to a class of rodent PPs.

Hydroxyurea-induced toxic side-effects in animals and an attempt at reducing them with vitamins E and C.

Using the changes in several blood parameters and in the histological picture of the liver as markers of toxicity, the effect of hydroxyurea (HU) in healthy rabbits or mice was examined during two weeks after a single administration of this drug. In rabbits a transient significant decrease in blood erythrocyte count with a gradual increase in their osmotic resistance, a suppression of granulocyte phagocytic capacity, and an elevation of acid phosphatase activity in the serum were found. An increase in the proportion of lymphocytes without detectable lysosomes as tested by supravital staining also appeared. No significant difference was observed in the white cell count and lipoperoxide levels after HU administration. Histological picture of the liver, excised from HU-treated mice, indicated a marked hepatotoxicity of the drug. Some of the toxic effects were reduced in animals supplemented with vitamins E and C.

Degenerative changes, DNA synthesis and mitotic activity in rat liver following single and repeated exposure to fenarimol.

Degenerative changes were observed in liver of rats treated with single and repeated doses of fenarimol (250 mg/kg body weight x day). Regenerative changes i.e. increase in: DNA synthesis, hepatic DNA, mitotic activity and number of binuclear hepatocytes, were also noted.

[Changes in serum calcium level in rats as the effect of administration of fenarimol]. / Zmiany poziomu wapnia w surowicy krwi szczurów jako efekt dzialania fenarimolu.

The Ca2+ concentration in rats serum after intragastrically fenarimol administration (doses 1/40, 1/20 and 1/10 LD50) during 5 days was investigated. The significant decrease of Ca2+ concentration in serum after 3 and 5 days of fenarimol administration was observed.

[Protection of human peripheral blood leukocytes with vitamin E and C from toxic effects of fenarimol in vitro]. / Oslanianie leukocytów ludzkiej krwi obwodowej za pomoca witamin E i C przed skutkami toksycznego dzialania fenarimolu in vitro.

The work was undertaken in a trial to protect leukocytes against the toxic effect of fenarimol with vitamin E and C. The experiment was carried out in vitro. These vitamins were chosen since they are the components of the physiological antioxidative mechanism in the cell. The protective effect of the vitamins varied depending on the type of the cell and the studied structure as well as on the dose of the antioxidant used. Improvement of the phagocytic activity of the granulocytes was observed after preincubation with vitamin E and using vitamin C it was possible to achieve control values of the phagocytosis index and per cent of non-phagocytizing granulocytes. Both these vitamins in a satisfactory degree improved the morphological and quantitative pattern of lysosomes in cultured lymphocytes treated with fenarimol. The use of vitamin E in doses of 15 micrograms/ml and vitamin C - 0.5 microgram/ml, made possible achieving of complete normalization of the nucleologram in the lymphocytes. The observed effective protection of the leukocytes against the effects of fenarimol by means of antioxidants suggests that these cells are damaged by the mechanism of lipid peroxidation.

[The effect of selected polychlorinated hydrocarbon pesticides on proliferation of cells in rat liver (14 day experiment)]. / Wplyw wybranych pestycydów z grupy polichlorowanych weglowodorów na proliferacje komórkowa w watrobie szczurów (doswiadczenie 14 dniowe).

The aim of present studies was to describe the effect of two organochlorine pesticides: nuarimol and DDT on the changes in rat liver, proposed in the literature to be useful endpoints in screening of non-genotoxic hepatocarcinogens and/or liver tumor promoters. The effects on the following endpoints: mitogenesis (DNA synthesis and mitotic activity), hepatomegaly as well as histological changes in rat liver have been investigated. Male Wistar rats received nuarimol or DDT in one, five and fourteen daily oral administration of the doses of 125 and 12 mg/kg b.w. day-1 respectively. In the case of both pesticides the effects observed consisted of hepatomegaly and hepatocyte proliferation (DNA synthesis and mitotic activity), although our studies indicated several distinct differences in the hepatic response between nuarimol, on the one hand and DDT on the other. The differences were reflected in the character and the basal rate of hepatocyte proliferation. Nuarimol elicited rapid but transient wave of hepatocyte proliferation during the first day of exposure. As opposite to nuarimol, DDT induced sustained hepatocyte proliferation during experimental period (14 days). Moreover, DDT induced evident focal necrosis and abnormal mitoses whereas nuarimol caused only slight vacuolated cytoplasm. Thus it can be concluded that nuarimol induced in rat liver direct mitogenic effect. On the other hand, DDT which is well known hepatocarcinogen, was found to produce mitogenic effect appearing to be related to regenerative response, since histological signs of necrosis were apparent.

[Cytotoxic effect of fenarimol on peripheral blood cells and organs]. / Cytotoksyczne dzialanie fenarimolu na komórki krwi obwodowej i narzady.

The effect of fenarimol in blood cells and changes in liver and kidneys in rats were investigated. Fenarimol applied in doses 25 mg/ml intragastrically during 5 days, at 24h after the last doses caused functional and structural changes of blood cells and organs. The decreases of osmotic fragility of erythrocytes and phagocytic activity of neutrophils, and the increase of the percentage of lymphocytes without detectable lysosomes accompanied by the minor decrease of the number of blood cells was observed in the peripheral blood. The indistinctness of the structure of the hepatic lobules and of liver laminae and the vacuolized hepatic cells with pycnotic nuclei were visible in the liver. The abnormally enlarged cortical Malphighian++ glomeruli in kidney were found. The observed changes indicate the cytotoxic effect of fenarimol in strongly intoxicated rats. The impaired phagocytic activity of neutrophils may cause the growth of susceptibility to bacterial infection.

[Organ cytotoxicity of selected polycyclic aromatic hydrocarbons in mice]. / Cytotoksycznosc narzadowa wybranych policyklicznych weglowodorów aromatycznych (WWA) u myszy.

The cytotoxic effects of some PAHs: DMBA, 3-MC and B(a)P on the lymphatic organs, liver and kidney of mice have been investigated. These PAHs in doses of 100 mg/kg were dissolved in 0.5 ml 20% DMSO and were given intraperitoneally in female mice Balb/c. After 7 days, organs weight, cellularity in lymphoid organs and tissue structure of liver and kidney were analyzed. The greatest effect of DMBA was observed on cellularity of spleen. 3-MC and B(a)P caused significant hepatotoxic and nephrotoxic changes. 3-MC induced focal destruction of hepatocytes and sometimes--irregular mitotic figures (c-mitosis). After B(a)P administration in liver cells were mainly observed the changes in distribution of interphase nucleolar organizer region (AgNOR). In kidney--irregular glomeruli and tubuli after 3-MC and B(a)P were noted. The above results may indicate that the cytotoxic effects of PAHs depend on the type of compound administered.

Protective action of vitamin E on the subcellular structures of lymphocytes intoxicated with pesticides in vitro.

Vitamin E was used as a protection for human lymphocytes in vitro against the toxic effects of dichlorvos, an organic phosphate pesticide. As the markers of the toxic changes in the lymphocytes lysosomes were chosen as a membrane structure, and nucleoli as a structure connected with protein synthesis. The obtained results were compared with the effects obtained previously in analogous studies after intoxication of lymphocytes with lindan and fenarimol. The experiment showed that vitamin E protected the lysosomal membranes more effectively than the nucleolar structure in these cells.

Inhibition of leucocyte migration by cancer chemotherapeutic agents and its prevention by free radical scavengers and thiols.

The exposure of human blood in vitro to a range of concentrations of adriblastine, hydroxyurea, methotrexate, 5-fluorouracil, 6-mercaptopurine, cytosine arabinoside and nitrogen mustard induced reduction in leucocyte migration rate in all drug dilutions under study. The reduction was dose-dependent. This effect was used to examine the protection of alfa tocopherol, acetylosalicylic acid and thiourea against drug-induced cytotoxicity. It has been found that at the suitable concentration of the protecting agent, a preventive effect of tocopherol against toxicity of all drugs, except nitrogen mustard, can be achieved. Acetylosalicylic acid protected the cells against adriblastine, cytosine arabinoside, hydroxyurea and methotrexate toxicity. Thiourea prevented the toxic effect of adriblastine, fluorouracil, hydroxyurea, methotrexate and nitrogen mustard.

Protective effects of vitamins E and C on erythrocytes in blood preserved in ACD solution and stored at 4 degrees C.

Vitamins E and C were used for the enrichment of the fluid for blood preservation. Whole blood with added ACD solution and vitamins E and C was stored at 4 degrees C for 21 days. The performed determinations included: haematocrit, osmotic fragility of the erythrocytes, ATP and 2,3-DPG content in the erythrocytes, and echinocyte count. A protective effect of these vitamins on erythrocytes was manifested by the decreased osmotic fragility, the steep fall of 2,3-DPG compared with the blood preserved in the vitamin-free ACD solution.