Exposure to fractionated dose of 60 Gy affects molecular response of HL-60 cells to irradiation

In this work we evaluated changes in molecular response of human promyelocyte leukemia cells HL-60 and HL-60-IR cells (HL-60 irradiated by 10 cycles of radiation with total dose of 60 Gy, given over a period of 3 months) to irradiation by the dose of 2 and 8 Gy. Analysis of CD11b and apoptosis by flow-cytometry revealed that on 3rd day after irradiation by 8 Gy the HL-60-IR are more resistant to radiation-induced apoptosis and more differentiated (increase in CD11b in non-apoptotic cells) than regular HL-60. We found that both types of cells have high basal level of phosphorylated extracellular signal-regulated kinases Erk1/2 . Irradiation induces decrease in Erk1/2 phosphorylation after 4 and 8 h in both cell types. However, in HL-60-IR cells Erk1/2 phosphorylation is restored faster than in HL-60. Also it was found that in contrary to HL-60 cells, the HL-60-IR cells react to 2 Gy irradiation by p53 independent increase in p21(WAF1/Cip1), and not by activation of checkpoint kinase Chk-2. Therefore we concluded that relatively high dose of radiation (6 Gy) does not lead after 10 repetitive irradiations to eradication of HL-60 cells, but instead increases their radioresistance, increases the ability to differentiate, alters MAPK response, increases amount of p21(WAF1/Cip1), and decreases induction of apoptosis by ionizing radiation. p21(WAF1/Cip1) might prevent apoptosis induction and trigger permanent cell-cycle arrest, which can also contribute to regression of this leukaemia after therapy.

Confocal laser endomicroscopy in experimental pigs. Methods of ex vivo imaging

BACKGROUND

Confocal laser scanning endomicroscopy (CLSE) enables online in vivo cellular surface and subsurface imaging of normal and pathological tissue at high resolution and magnification. The aim of this study was to work out a method of ex vivo in vitro CLSE in experimental pigs and to compare CLSE images with those of "classic" histology.

MATERIAL AND METHODS

Five mature female pigs entered the study. CLSE on an ex vivo in vitro basis was started 10 minutes after pharmacological euthanasia and carried out for 30 minutes. Fluorescein was administrated i.v. as a fluorescence substance.

RESULTS

CLSE was successful in all tissue samples of all animals (the oesophagus, stomach, small intestine, large bowel). We have succeeded to obtain high quality images within the first 30 minutes that means 40 minutes after the euthanasia of experimental animals. CLSE images corresponded well with those of haematoxylin-eosin staining.

CONCLUSIONS

CLSE on an ex vivo in vitro basis in experimental pigs is feasible.

Gamma-radiation-induced phosphorylation of p53 on serine 15 is dose-dependent in MOLT-4 leukaemia cells

Molecular indicators of the absorbed dose of ionizing radiation are powerful tools in biodosimetry. The studies reported here were undertaken with the motivation to find such a marker among the mo lecules involved in ataxia-telangiectasia mutated kinase- dependent signalling induced by ionizing radiation (ATM-kinase, checkpoint kinase-2, protein p53, and oncoprotein Mdm2). In our previous work on T-lymphocyte leukaemia MOLT-4 cells we described the mentioned molecules of ATM-dependent pathway and none of them showed a pronounced dosedependent response. Here we employed Western blotting and ELISA assay to investigate the response of post-translationally modified p53 (particularly phosphorylated on serine 15) after gamma-irradiation. We have found the amount of phosphorylated p53 to be homogenously increased after irradiation by the doses of 0.5 to 7.5 Gy. The dose-dependent response was pronounced especially after the doses up to 3.0 Gy. The presented data indicate that p53 phosphorylated on serine 15 might be used as a potential biodosimetric marker.

Different solutions used for submucosal injection influenced early healing of gastric endoscopic mucosal resection in a preclinical study in experimental pigs

Background

We hypothesised that different solutions for submucosal injection may influence early healing of endoscopic mucosal resection (EMR). The aim of this study was to evaluate histological and immunological changes after EMR in experimental pigs.

Materials and methods

Two parallel EMRs on the anterior and posterior wall of the gastric body were performed by means of the cap technique in 21 female pigs. A glycerol-based solution (anterior EMR) and hydroxypropyl methylcellulose solution (posterior EMR) were applied for submucosal injection. The animals were sacrificed 7 days later, and tissue sections of all EMRs were stained using combined trichrome. Computer image analysis was used for objective evaluation of elastic and collagen fibres content. Two-colour indirect immunophenotyping of blood and gastric samples were performed using mouse anti-pig monoclonal antibodies.

Results

The values of collagen fibre content 7 days after EMR were significantly higher in lesions after the use of solution A in comparison with solution B (2.10 ± 0.25% versus 1.57 ± 0.25%, p = 0.009). Concordant results were found in elastic fibres (3.23 ± 0.49% versus 2.93 ± 0.61%, p = 0.018). No systemic changes in major leukocyte subpopulations were found. In gastric tissue, lymphocyte subsets exhibited only minor changes. CD4⁺ T-lymphocytes were increased in the healing tissue after EMR using solution A (17.08 ± 9.24% versus 9.76 ± 7.97%, p = 0.011). Significant increase of SWC3⁺ leukocytes was observed after EMR using solution B (47.70 ± 25.41% versus 18.70 ± 12.16%, p = 0.001).

Conclusions

The use of glycerol-based solution for submucosal injection was associated with more pronounced histological signs of early healing of EMRs compared with hydroxypropyl methylcellulose.

The influence of acetylcholinesterase reactivators on selected hepatic functions in rats

The aim of our study was to evaluate the impact of acetylcholinesterase reactivators--K027 [1-(4-carbamoyl pyridinium)-3-(4-hydroxyiminomethyl pyridinium) propane dibromide], HI-6 [1-(4-carbamoylpyridinium)-3-(2-hydroxyimino methylpyridinium) oxapropane dichloride] and obidoxime [1,3-bis(4-hydroxyiminomethyl pyridinium)oxapropane dichloride] on hepatic functions in vivo. Male Wistar rats were randomly divided to seven groups and intramuscularly administered with saline and acetylcholinesterase reactivators (K027, HI-6 and obidoxime) at doses of 5% LD(50) and 50% LD(50). Liver tissue samples were taken 24 hr after administration. Histochemical detection of lipid droplets and immunohistochemical detection of multidrug resistance protein 2 (Mrp2) were provided. Lipid droplet count in rat liver did not show any significant differences in animals administered with K027, HI-6 and obidoxime in comparison with the control group. Mrp2 protein expression significantly decreased when animals were administered with K027 at a dose of 50% LD(50) and HI-6 and obidoxime at doses of 5% LD(50) and 50% LD(50), when compared to the controls. No statistical differences of Mrp2 expression were measured when animals were administered with K027 at a dose of 5% LD(50) in comparison with control animals. We found impaired hepatic transporter function after administration of HI-6, obidoxime and higher concentration of K027, which might be the underlying mechanism of acetylcholinesterase reactivators' hepatotoxicity.

Alteration of Mitogen-Activated Protein Kinase Pathway After Soman Poisoning

The p38 mitogen-activated protein kinase (MAPK) and activated MAPK transcription factors c-jun, c-myc, and elk-1 were investigated in rat enterocytes after sublethal poisoning with soman to study the pathogenetic mechanism of nonspecific long-term effects of nerve agents. Wistar rats were poisoned by intramuscular administration of soman at a dose 60 microg x kg(-1) (70% LD(50)) and sacrificed by cervical dislocation 3 and 5 days after poisoning. Control groups were administered physiologic saline instead of soman. Protein expression in immunohistochemically stained samples from colon transversum of control and poisoned rats was measured using image analysis. In comparison with control groups, activated p38 MAPK from soman-poisoned rats was significantly depressed at both time intervals. c-myc and c-jun expression was significantly increased 3 days after soman poisoning. On the other hand, a decrease in c-myc and c-jun expression was observed 5 days after soman poisoning. No changes in elk-1 expression were found. Long-term depression of MAPK pathway members might allow cells to proliferate in poisoned rats. This mechanism can be linked with apoptosis and carcinogenesis.

Gamma irradiation of human leukaemic cells HL-60 and MOLT-4 induces decrease in Mcl-1 and Bid, release of cytochrome c, and activation of caspase-8 and caspase-9

PURPOSE

Apoptosis is significantly controlled by proteins of Bcl-2 (B-cell lymphoma 2) family promoting cell death or maintaining cell survival. We selected two representatives of Bcl-2 family (anti-apoptotic Mcl-1 - myeloid cell line-1 and pro-apoptotic Bid - Bcl-2 homology domain 3 interacting death agonist), cytochrome c (cyt-c), and two initial caspases (-8 and -9) to evaluate their function in ionizing radiation (IR)-induced apoptosis in human leukaemic cell lines diverging in p53 (TP53 tumor suppressor gene) status.

MATERIALS AND METHODS

A total of 30 microg of proteins of whole-cell lysates or 10 microg of mitochondrial protein fractions were electrophoretically separated and analyzed by Western-blotting.

RESULTS

Here we show that in both HL-60 (p53 null) and MOLT-4 (p53 wild type) leukaemic cells the amount of Mcl-1 initially increased after irradiation by sublethal but not by lethal dose and later (when apoptosis occurred) it decreased in a dose-dependent manner. Caspase-8 was cleaved and afterwards the amount of Bid decreased as it was truncated. We also found cyt-c release from the inner mitochondrial membrane space into cytoplasm to be dose-dependent and it was followed by induction of apoptosis. In the p53-null cells caspase-8 was activated prior caspase-9, whereas the cells harboring p53 exhibited a simultaneous activation of both initial caspases.

CONCLUSION

IR induced a decrease in Mcl-1, activation of Bid, caspase-8, and -9, and release of cyt-c. Presented data indicate that both extrinsic and intrinsic apoptosis signalling pathways were activated in HL-60 and MOLT-4 cells upon exposure to IR regardless to the p53 status.

Zonation of multidrug resistance-associated protein 2 in rat liver after induction with dexamethasone

BACKGROUND AND AIM

The present study was aimed to evaluate the hepatic zonation of multidrug resistance-associated protein 2 (mrp2), an important drug transporter, and its potential changes during the induction of its expression by known inducer, dexamethasone (DEX).

METHODS

The hepatic expression of mrp2 was studied by immunohistochemistry with consequent quantification by measurement of integral optical densities of mrp2 staining in the periportal and perivenous areas of the liver acinus in control and DEX-pretreated rats (1 mg/kg daily per os for 4 days). Overall changes in mrp2 expression and function produced by DEX were monitored using Western blotting and an in vivo clearance study of endogenous-conjugated bilirubin, a mrp2 substrate.

RESULTS

In the control animals, a quantitative image analysis revealed the primary periportal localization of mrp2 within the liver acinus with the expression of mrp2 being 16.7-fold of that in the perivenous area. After DEX pretreatment, the expression of mrp2 increased, especially in the perivenous hepatocytes. The overall expression of mrp2 increased 3.2-fold in comparison with the control group. This observation was confirmed by Western blotting, which showed a 1.3-fold increase in the mrp2 protein after DEX pretreatment. The functional consequences of the induced mrp2 protein in the livers of the DEX-pretreated rats were demonstrated by the increased biliary excretion of conjugated bilirubin.

CONCLUSION

In conclusion, these results indicate the zonation of mrp2 protein expression primarily to periportal hepatocytes. The induction by DEX produced spatially disproportional changes with an increase in the mrp2 protein being most prominent in the perivenous hepatocytes.

Changes in phosphorylation of histone H2A.X and p53 in response of peripheral blood lymphocytes to gamma irradiation

The main aim of this study was to compare the reaction of quiescent and proliferating, i.e. phytohemagglutinin (PHA)-stimulated, human peripheral blood mononuclear cells (PBMCs) to gamma-radiation, and analyse changes of proteins related to repair of DNA damage and apoptosis, such as gammaH2A.X, p53, p53 phosphorylation at serines-15 and -392, and p21 and their dose dependence. Freshly isolated PBMCs in peripheral blood are predominantly quiescent, in G(0) phase, and with very low amounts of proteins p53 and p21. Using confocal microscopy we detected dose dependent (0.5-5 Gy) induction of foci containing gammaH2A.X (1 h after gamma-ray exposure), which are formed around radiation-induced double strand breaks of DNA. Apoptosis was detected from 24 h after irradiation by the dose of 4 Gy onwards by Annexin V binding and lamin B cleavage. Seventy two hours after irradiation 70% of CD3(+) lymphocytes were A(+). Neither increase in p53 nor its phosphorylation on serine-392 after irradiation was detected in these cells. However, massive increase in p21 (cyclin-dependent kinase inhibitor 1A) was detected after irradiation, which can be responsible for late occurrence of apoptosis in these quiescent cells. PHA-stimulation itself (72 h) caused an increase in early apoptosis (A(+)PI(-)) in comparison to non-stimulated PBMCs (38% A(+) resp. 13.4%). After PHA-stimulation also the amount of gammaH2A.X, p53, and p21 increased, but no phosphorylation of p53 on serine-392 or -15 was detected. Reaction to gamma-radiation was different in PHA-stimulated lymphocytes: the p53 pathway was activated and p53 was phosphorylated on serines-15 and -392 4 h after irradiation by the dose of 4 Gy. Phosphorylation of p53 at serine-15 increased in a dose-dependent manner in the studied dose range 0.2-7.5 Gy. Also the amount of p21 increased after irradiation. Seventy two hours after irradiation of PHA-stimulated CD3(+) T lymphocytes by the dose of 4 Gy 65% of cells were A(+).

Re-expression of nestin in the myocardium of postinfarcted patients

Intact cardiac muscle cells in the adult heart do not express intermediate filament nestin. In this study, we report on widespread expression of intermediate filament nestin in human myocardium of patients who died from the myocardial infarction. Nestin was detected in cardiomyocytes, endothelial cells, and few interstitial cells. Elevated levels of nestin were observed in cardiac muscle cells in all specimens, although the intensity of immunoreactivity and distribution of the signal differed. The strongest immunoreactivity was observed from 4 days after myocardial infarction in the infarction border zone where nestin was distributed homogeneously in the entire sarcoplasm of cardiac muscle cells. Within the following week, nestin in immunoreactive cardiomyocytes was redistributed and restricted to small subsarcolemmal foci and to intercalated discs. Angiogenic capillaries that grew between vital nestin-positive cardiomyocytes and entered the necrotic area expressed also high levels of nestin. Nestin-positive endothelial cells were often observed in mutual interactions with nestin-positive cardiac muscle cells. These findings document a crucial role of nestin in remodeling cytoskeleton of cells in the human postinfarcted myocardium.

Changes in phosphorylation of histone H2A.X and p53 in response of peripheral blood lymphocytes to gamma irradiation

The main aim of this study was to compare the reaction of quiescent and proliferating, i.e. phytohemagglutinin (PHA)-stimulated, human peripheral blood mononuclear cells (PBMCs) to gamma-radiation, and analyse changes of proteins related to repair of DNA damage and apoptosis, such as gammaH2A.X, p53, p53 phosphorylation at serines-15 and -392, and p21 and their dose dependence. Freshly isolated PBMCs in peripheral blood are predominantly quiescent, in G(0) phase, and with very low amounts of proteins p53 and p21. Using confocal microscopy we detected dose dependent (0.5-5 Gy) induction of foci containing gammaH2A.X (1 h after gamma-ray exposure), which are formed around radiation-induced double strand breaks of DNA. Apoptosis was detected from 24 h after irradiation by the dose of 4 Gy onwards by Annexin V binding and lamin B cleavage. Seventy two hours after irradiation 70% of CD3(+) lymphocytes were A(+). Neither increase in p53 nor its phosphorylation on serine-392 after irradiation was detected in these cells. However, massive increase in p21 (cyclin-dependent kinase inhibitor 1A) was detected after irradiation, which can be responsible for late occurrence of apoptosis in these quiescent cells. PHA-stimulation itself (72 h) caused an increase in early apoptosis (A(+)PI(-)) in comparison to non-stimulated PBMCs (38% A(+) resp. 13.4%). After PHA-stimulation also the amount of gammaH2A.X, p53, and p21 increased, but no phosphorylation of p53 on serine-392 or -15 was detected. Reaction to gamma-radiation was different in PHA-stimulated lymphocytes: the p53 pathway was activated and p53 was phosphorylated on serines-15 and -392 4 h after irradiation by the dose of 4 Gy. Phosphorylation of p53 at serine-15 increased in a dose-dependent manner in the studied dose range 0.2-7.5 Gy. Also the amount of p21 increased after irradiation. Seventy two hours after irradiation of PHA-stimulated CD3(+) T lymphocytes by the dose of 4 Gy 65% of cells were A(+).

Expression of phospho-Elk-1 in rat gut after the whole body gamma irradiation

Gastrointestinal form is the second stage of acute radiation syndrome (ARS) with a threshold dose of 8 Gy in man. It represents an absolutely lethal clinical-pathological unit, necro-hemorrhagic enteritis and proctocolitis, with unknown causal therapy. Elk-1 is a protein acting as a transcription factor activating specified genes. The purpose of our study was to examine the expression of phospho-Elk-1 in irradiated jejunum and transversal colon of rats with radiation-induced enterocolitis and to assess the importance of this transcriptional factor as a biodosimetric marker of radiation-induced enteropathy. The laboratory rats were randomly divided into 21 groups, 10 animals per group, and irradiated with whole body gamma-irradiation of 1, 5, 10, 15, and 20 Gy. Samples of jejunum and transversal colon were taken 24, 48, 72, and 96 hours later, immunohisto-chemically stained, and the phospho-Elk-1 expression was examined using computer image analysis. A group of 10 sham-irradiated animals was used as control. Significantly increased expression of phospho-Elk-1 in rat jejunum has been found in all time intervals after irradiation by sublethal doses of 1 and 5 Gy, whereas after the irradiation by lethal doses, the expression of phospho-Elk-1 in rat jejunum varied considerably. Significantly increased expression of phospho-Elk-1 in transversal colon has also been found in the first days after irradiation by sublethal doses of 1 and 5 Gy. After irradiation by lethal doses, there was no uniform pattern of the changes in the expression of phospho-Elk-1 in rat transversal colon. The detection of phospho-Elk-1 might be considered as a suitable and very sensitive biodosimetric marker of radiation-induced injury of small and large intestine. According to our knowledge, this is the first study on the phospho-Elk-1 expression in irradiated jejunum and transversal colon in the rat.

CD27(+) peripheral blood B-cells are a useful biodosimetric marker in vitro

The CD8(+) natural killer (NK) subpopulation has recently been identified as a fast and reliable biodosimetric indicator within human peripheral blood mononuclear cells (PBMC) in vitro. In irradiated and subsequently cultivated PBMC, a decrease of the relative number of intact CD3(-)CD8(+) lymphocytes 16 and 48 h after treatment has allowed for estimating the received dose in the range of 0 - 10 Gy and lethal/sublethal dose discrimination, respectively. Here we show that suitable biodosimeters can also be found in the peripheral blood B-cell compartment. Multiparameter flow cytometric analysis of irradiated and subsequently cultivated human PBMC revealed that both the CD27(+) and CD21(-) B-cell subpopulations can be used as biodosimeters and the CD19(+)CD27(+) lymphocytes have proved useful for retrospective determination of the received dose in the range of 0 - 6 Gy. In addition, several CD19(+) lymphocyte subsets characterized by co expression of CD21, CD27 and CD38 have been shown to bear biodosimetric potential, too. However, when important parameters like the original size within the CD19(+) compartment, its radiation-induced changes and data variation had been taken into account, the CD27(+) subpopulation proved superior to the other B-cell subpopulations and subsets. It appears that, in the dose range of 0 - 6 Gy, the relative decrease of CD27(+) B lymphocytes provides more sensitive and reliable data than that of CD8(+) NK-cells due mainly to lower data variation. In contrast to CD27(+) B cells, the proportions of CD27(+) subpopulations of T-cells were not affected by irradiation. We have also proposed a simple experimental protocol based on full blood cultivation and three-color CD27/CD3/CD19 immuno-phenotyping as a time-saving and inexpensive approach for practical biodosimetric evaluations on simple, three-to-four color flow cytometers.

Gamma-radiation-induced ATM-dependent signalling in human T-lymphocyte leukemic cells, MOLT-4

ATM kinase (ATM) is essential for activation of cell cycle check points and DNA repair in response to ionizing radiation (IR). In this work we studied the molecular mechanisms regulating DNA repair and cell death in human T-lymphocyte leukemic cells, MOLT-4. Apoptosis was evaluated by flow-cytometric detection of annexin V. Early apoptotic cells were determined as sub-G1 cells and late apoptotic cells were determined as APO2.7-positive ones. Proteins involved in ATM signalling pathway were analysed by Western-blotting. We observed a rapid (0.5 h) phosphorylation of ATM declining after 6 h after irradiation by all the doses studied (1.5, 3.0, and 7.5 Gy). Checkpoint kinase-2 (Chk-2) was also phosphorylated after 0.5 h but its phosphorylated form persisted 4, 2, and 1 h after the doses of 1.5, 3.0, and 7.5 Gy, respectively. The amount of p53 protein and its form phosphorylated on Ser-392 increased 1 h after irradiation (1-10 Gy). The lethal dose of 7.5 Gy caused an immediate induction and phosphorylation of p53 after 0.5 h post-irradiation. At the time of phosphorylation of p53, we found simultaneous phosphorylation of the oncoprotein Mdm2 on Ser-166. Neither ATM nor its downstream targets showed a dose-dependent response after 1 h when irradiated by the doses of 1-10 Gy. MOLT-4 cells were very sensitive to the effect of IR. Even low doses, such as 1.5 Gy, induced apoptosis 16 h after irradiation (evaluated according to the cleavage of nuclear lamin B to a 48-kDa fragment). IR-induced molecular signalling after exposure to all the tested doses was triggered by rapid phosphorylation of ATM and Chk-2. Subsequent induction of p53 protein and its phosphorylation was accompanied by concomitant phosphorylation of its negative regulator, oncoprotein Mdm2, and followed by induction of apoptosis.

Morphological changes of rat jejunum after whole body gamma-irradiation and their impact in biodosimetry

Gastrointestinal form is the second stage of the Acute Radiation Syndrome (ARS) with a threshold dose of 8 Gy. It represents an absolutely lethal clinical-pathological unit, enteritis necro-hemorrhagica (duodenitis, jejunitis, ileitis, respectively) with unknown causal therapy. The purpose of our study has been to evaluate the morphological changes in a model of radiation-induced enteritis in rats and estimate the significance of changes in biodosimetry. Wistar rats were randomly divided into 21 groups, 10 animals per group. Samples of the jejunum were taken 24, 48, 72, and 96 h after the whole-body gamma-irradiation with the doses of 1, 5, 10, 15, and 20 Gy, and routinely stained with hematoxylin and eosin. Five morphometric markers--intercryptal distance, enterocytal height on the top and base of villus, length of basal lamina of 10 enterocytes and enterocytal width--in irradiated rat jejunum were examined. The results were compared with sham-irradiated control group. After lethal doses of irradiation, all morphometric parameters of jejunum significantly changed. With the exception of intercryptal distance, they might be considered as suitable biodosimetric markers under these experimental conditions. Our morphometry results in radiation-induced jejunitis are in accordance with those in other studies. We were the first who quantified morphological post-irradiation changes in animal jejunum. Some of them might be used under experimental conditions. This experimental study is a predecessor of the clinical assessment of a specific marker. Under clinical practice, the sensitive biodosimetric parameter could serve as one of the guidance for evaluation of the absorbed dose in irradiated troops as well as rescue workers. This is in accordance with tasks and Standardization Agreement of the North Atlantic Treaty Organization.

Morphological and functional changes in p-glycoprotein during dexamethasone-induced hepatomegaly

1. The effect of dexamethasone on hepatic and renal P-glycoprotein (P-gp) expression, localization and activity was investigated in rats after 4 days oral administration of two dose regimens (1 or 25 mg/kg per day). Simultaneous increases in liver weight were evaluated by quantitative histological examination. 2. In the liver, dexamethasone pretreatment produced hepatomegaly as a consequence of extensive periportal fat accumulation, which was quantified by densitometry of oil red O-stained liver sections. Quantitative immunohistochemical analysis revealed preferential periportal zonation of P-gp in control animals. Dexamethasone pretreatment resulted in spatially disproportional induction of P-gp protein expression within the liver acinus characterized by preferential increase in pericentral areas, with consequent uniform panlobular distribution. Western blot analysis confirmed these results, showing increases in P-gp protein. Quantitative reverse transcription-polymerase chain reaction analysis revealed no statistically significant change in liver mdr1b mRNA expression after either dexamethasone treatment regimen. The expression of mdr1a mRNA was significantly decreased by 85-87%. 3. In the kidney, dexamethasone reduced mdr1a mRNA expression by 69-89%, whereas mdr1b mRNA expression was increased in a dose-dependent manner. However, despite tendencies, no significant increases in P-gp expression were observed at the protein level. 4. The in vivo function of P-gp was evaluated by measuring renal and biliary secretion of rhodamine-123 (Rho123) under a steady state plasma concentration. The biliary, renal and tubular secretory clearance of Rho123 was significantly increased only after high-dose dexamethasone. 5. In conclusion, the present study suggests that drug interactions observed during corticosteroid therapy may be mediated, at least in part, through increased biliary, and also renal, excretion of P-gp substrates. Expression of P-gp in the liver showed primary periportal zonation with differential changes during induction. Accompanying hepatomegaly may be explained by severe microvesicular steatosis selectively localized to the periportal areas.

Oncogynaecological quadruplicity--case report

A case of a 54-year-old woman with bilateral breast, endometrial, and ovarian cancer was referred to our clinic by the Oncology Department where she had been treated with chemotherapy for the breast cancer. The clinical aspects of this unique case and follow-up are presented. This is the first such serious case of primary oncogynaecological quadruplicity to be described in the literature. Forty-two months after the initial diagnosis, the patient is in good health with no signs of cancer recurrence.

Gamma-radiation-induced ATM-dependent signalling in human T-lymphocyte leukemic cells, MOLT-4

ATM kinase (ATM) is essential for activation of cell cycle check points and DNA repair in response to ionizing radiation (IR). In this work we studied the molecular mechanisms regulating DNA repair and cell death in human T-lymphocyte leukemic cells, MOLT-4. Apoptosis was evaluated by flow-cytometric detection of annexin V. Early apoptotic cells were determined as sub-G1 cells and late apoptotic cells were determined as APO2.7-positive ones. Proteins involved in ATM signalling pathway were analysed by Western-blotting. We observed a rapid (0.5 h) phosphorylation of ATM declining after 6 h after irradiation by all the doses studied (1.5, 3.0, and 7.5 Gy). Checkpoint kinase-2 (Chk-2) was also phosphorylated after 0.5 h but its phosphorylated form persisted 4, 2, and 1 h after the doses of 1.5, 3.0, and 7.5 Gy, respectively. The amount of p53 protein and its form phosphorylated on Ser-392 increased 1 h after irradiation (1-10 Gy). The lethal dose of 7.5 Gy caused an immediate induction and phosphorylation of p53 after 0.5 h post-irradiation. At the time of phosphorylation of p53, we found simultaneous phosphorylation of the oncoprotein Mdm2 on Ser-166. Neither ATM nor its downstream targets showed a dose-dependent response after 1 h when irradiated by the doses of 1-10 Gy. MOLT-4 cells were very sensitive to the effect of IR. Even low doses, such as 1.5 Gy, induced apoptosis 16 h after irradiation (evaluated according to the cleavage of nuclear lamin B to a 48-kDa fragment). IR-induced molecular signalling after exposure to all the tested doses was triggered by rapid phosphorylation of ATM and Chk-2. Subsequent induction of p53 protein and its phosphorylation was accompanied by concomitant phosphorylation of its negative regulator, oncoprotein Mdm2, and followed by induction of apoptosis.

Differentiation of neural stem cells into cells of oligodendroglial lineage

We described three different conditions that induce differentiation of dissociated neural stem cells derived from mouse embryonic CNS. In the first set of experiments, where the cell differentiation was triggered by cell adhesion, removal of growth factors and serum-supplemented medium, only sporadic neuronal and astroglial cells survived longer than two weeks and the latter formed a monolayer. When differentiation was induced in serum-free medium supplemented with retinoic acid, rapid and massive cell death occurred. A prolonged survival was observed in cultivation medium supplemented with serum and growth factors EGF plus FGF-2. One third of the cells did not express cell differentiation markers and were responsible for an increase in cell numbers. The remaining cells differentiated and formed the astrocytic monolayer on which occasional neuronal cells grew. One third of the differentiated phenotypes were represented by cells of oligodendroglial lineage. Differentiation of oligodendroglial cells occurred in a stepwise mechanism because the culture contained all successive developmental stages, including oligodendrocyte progenitors, preoligodendrocytes and immature and mature oligodendrocytes. Maturing oligodendrocytes displayed immunocytochemical and morphological features characteristic of cells that undergo physiological development. The cultivation conditions that supported growth and differentiation of neural stem cells were optimal for in vitro developmental studies and the production of oligodendroglial cells.

Progressive Reparative Gliosis in Aged Hosts and Interferences with Neural Grafts in an Animal Model of Huntington's Disease

1. Neural transplantation in Huntington's diseased patients is currently the only approach in the treatment of this neurodegenerative disorder. The clinical trial, unfortunately, includes only a small number of patients until now, since many important questions have not been answered yet. One of them is only mild to moderate improvement of the state in most of grafted patients. 2. We examined the morphological correlates in the response to intrastriatal grafting of fragments of foetal rat ventral mesencephalic tissue 1 month after transplantation in male Wistar rats within varying durations (from 2 to 38 weeks) of experimentally induced neurodegenerative process of the striatum (used as a model of Huntington's disease). Our goal was to determine the impact of advanced striatal damage and gliosis on the graft viability and host-graft integration. 3. The findings can be summarized as follows: The progressive reactive gliosis, which is not able to compensate continual reduction of the grey matter leading to an extensive atrophy of the striatum in a long-term lesions, results in formation of the compact glial network. This tissue cannot be considered the suitable terrain for successful graft development and formation of host-graft interconnections. 4. The progression of irreversible morphological changes in long-lasting neurodegenerative process within the striatum can be supposed one of the important factors, which may decrease our prospect of distinct improvement after neural grafting in patients in advanced stage of Huntington's disease, who still remain the leading group in clinical trials.

Proliferation and Differentiation of Adult Endogenous Neural Stem Cells in Response to Neurodegenerative Process within the Striatum

The ongoing process of neurogenesis in the adult mammalian forebrain suggests the possible capacity for limited self-repair after brain injury. Previously, we have demonstrated that in an animal model of Huntington's disease the neurodegenerative process initiates immediate intensive cell proliferation and differentiation resulting in characteristic enlargement of the subependymal zone (SEZ) of lateral brain ventricles. Now, our interest is focused on the architecture of the neurogenic niche of the SEZ in the identical model, particularly on characteristic features of astrocyte-like cells which are considered to be not only niche cells but also neural stem cells. Our findings prove higher activation of the lateral part of the SEZ (L-SEZ) adjacent to the degenerated striatum compared with the rostral part of the SEZ (R-SEZ). In the activated L-SEZ, niche cells which ensheathe clusters of neural progenitors are of immature astrocytic phenotype because of nestin and vimentin expression (except the expression of glial fibrillary acidic protein). However, the coexpression of all three filaments is not always found. Intermediate filaments also enable us to distinguish the basic shape of astrocytic cells within the SEZ, majority of which resemble protoplasmic rather than fibrillary astrocytes. Furthermore, our results show a wide plasticity of these astrocyte-like cells in immediate response to an extensive pathological process in the brain. These observations are consistent with the fact that adult stem cells undergo different processes in an already mature environment, and therefore can exhibit some specific characteristics unlike the embryonic or fetal neural stem cells.

Nestin expression by newly formed human blood vessels

Nestin is a type VI intermediate filament protein originally described in neural stem cells. Here we report that immature endothelial cells generated in the course of angiogenesis express nestin. Endothelial cells of embryonic capillaries destined to vascularize growing organs also express this intermediate filament protein. Whereas nestin was sporadically expressed in mature adult human endothelial cells sporadically express nestin, this protein was consistently expressed in adult angiogenic vasculature. Nestin expression was also detected in capillaries of the corpus luteum, which replenishes itself by angiogenesis. Nestin-immunoreactive vessels were also observed in the infarcted hearts where transient ischemia triggered regeneration accompanied with neovascularization of the myocardium. Nestinpositive endothelial cells lined vessels nourishing solid growing tumors, including melanoblastomas and glioblastomas. Our data provide definitive evidence that endothelial precursors express the neural stem cell marker nestin and that this protein participates in formation of the cytoskeleton of newly formed endothelial cells. Because nestin expression was recognized under all conditions of vascular development, nestin represents a novel and reliable marker of neovascularization.

Role of type II pneumocytes in pathogenesis of radiation pneumonitis: dose response of radiation-induced lung changes in the transient high vascular permeability period

We studied the dose response of pulmonary changes at 3 weeks after 1-25 Gy irradiation and we investigated the effects of an anti-inflammatory drug. Wistar rats were given a single dose of 1-25Gy irradiation to the thorax. Group one was treated with saline only, while group two was administered subcutaneously a combination of pentoxifylline (35 mg/kg) and dexamethasone (1 mg/kg) twice per week. Lungs were examined histochemically and number of neutrophile granulocytes, alveolar septal thickness, air/tissue ratio, number of alveoli per field, number of type II pneumocytes per alveolus, and occludin 1 expression were measured. A significant dose-dependent depletion of type II pneumocytes was found after irradiation with a dose of 1 Gy and higher. Alveolar neutrophils increased after 1 Gy with a dose dependency noted after 10-25Gy and alveolar septa thickening followed 5-25 Gy. A lower occludin 1 expression was observed in animals irradiated with the doses of 5 20 Gy, indicating an effect on vascular permeability. Anti-inflammatory therapy partially inhibited the increase of neutrophils at all radiation doses and the depletion of type II pneumocytes after doses of 1, 10, and 15 Gy. Occludin 1 did not decrease in the lungs of rats treated with the anti-inflammatory drugs as it did in most rats treated only with saline. Our results suggest that pneumocytes depletion is a major factor responsible for radiation pneumonitis development and that these changes may be compensated for provided radiation doses are below the threshold.

Expression of MRP2 and MDR1 transporters and other hepatic markers in rat and human liver and in WRL 68 cell line

Here we describe a comparative study of phenotypic properties of hepatic cells in situ and in vitro. We analyzed the expression levels and distribution patterns of ABC transporters MRP2 and MDR1, pan-cytokeratin, cytokeratin 18, albumin, alpha-fetoprotein and the specific hepatocyte marker OCH1E5 in the fetal and adult rat as well as human liver tissue and in human fetal hepatocytes of WRL 68 cell line using peroxidase immunohistochemistry or immunofluorescence. Transporters MRP2 and MDR1 were expressed in all examined liver tissues, except rat ED13 embryo. The immunopositivity of these proteins was localized to the canalicular membrane of differentiating and mature hepatocytes but in the later developmental stages and in the adult liver tissues it was also found in the apical membrane of cholangiocytes. In WRL 68 cells, MRP2 and MDR1 immunoreactivity appeared after 5-6 days of cultivation and both transporters were fully expressed in the plasmalemma and in the cytoplasm 9 days after the passage. In conclusion, we observed only moderate variances reflecting diverse ontogenetic phases between the fetal and adult liver tissue. To study functions of hepatocytes in vitro, WRL 68 cells have to differentiate prior to the examination. Our findings indicate that WRL 68 cells can undergo differentiation in vitro and their antigenic profile closely resembles hepatocytes in the human liver.

[Proliferation and differentiation of neural stem cells within the subependymal layer of lateral brain ventricles in response to the neurodegenerative process in the striatum]

It is known that the subependymal layer (SEL) of the lateral brain ventricles' wall is a source of neural stem cells (NSCs) of adult mammalian brain including the human brain. The NSCs in relation to the striatum differentiate only into glial phenotype. Therefore we focused on proliferative activity of NSCs and precursors in the SEL and on the course of their differentiation into the astrocytes in reaction to the neurodegenerative process in the striatum like in Huntington's disease. Increased gliogenesis, differentiation of newly generated cells and their ability to migrate into the striatum were evaluated in two groups of the rats surviving 1 and 3 months after the application of the neurotoxic (ibotenic) acid into the striatum. For evaluation of the proliferative activity we compared the results obtained using two proliferative markers--Bromodeoxyuridine (BrdU) and Ki-67. Characterization of newly generated cells and of their differentiation was based on the detection using the following antibodies: Nestin (a marker for NSCs and precursors), GFAP (detection of astrocytes), also the double-staining method with BrdU and GFAP.

Radioprotective effects of amifostine (WR-2721) or cystamine on radiation damage and its repair in rats whole body exposed to fission neutrons

Sulphur containing radioprotective drugs amifostine (gammaphos, WR-2721) or cystamine (disulfide of meracaptoethylamine) of Czechoslovak production were examined in whole body fission neutrons irradiated rats in the thermal column of reactor VVR-S. Using the split-dose technic the first sublethal neutron dose in the range 1-2 Gy was followed by second lethal exposures in the two time intervals (3 or 6 days) using whole body fission neutrons irradiations (3 days interval) or whole body gamma-irradiations (6 days interval) for LD50/30 evaluation within next 30 days survival observation. In other experiments the mean survival time (MST) in days was estimated in different rats group, when animals were whole body fission neutrons irradiated twice with 3-days interval using the total lethal doses of 4 or 5 Gy. Protected rats received amifostine (160 mg.kg(-1) i.p. and 200 mg.kg(-1) i.m.) or cystamine (40 mg.kg(-1) i.p. and 50 mg.kg(-1) i.m.), control rats obtained saline 20 min before beginning of irradiation in the amount of 0.5 ml.100 g(-1) of the rat's body weight. Non-significant DRF value 1.13 for WR-2721 i.p. was calculated in survival studies in rats twice neutron irradiated with 3 days interval (DRF 1.04 for cystamine). Chemical protectors were administered before each neutron exposure. MST of twice neutron lethal iradiated rats was prolonged not regularly by radioprotectors tested. WR-2721 and cystamine i.m. were not able to increase 6 days reparation processes after sublethal 2 Gy fission neutrons whole body irradiated rats.

The reaction of the subependymal layer of lateral brain ventricles to striatal ibotenic acid lesions in a long-term study

The proliferative activity in the subependymal layer of lateral brain ventricles in adulthood is known. We were interested in the reaction of this layer to ibotenic acid lesions, which simulate neurodegenerative processes in Huntington's disease. Animals with a unilateral ibotenic acid lesion were compared with sham-lesioned animals and control animals with intact brains at 5 and 13 weeks after surgery. Five weeks after surgery, increased proliferation was found in most GFAP-positive astrocytes and to a lesser extent in CNPase-positive oligodendrocytes in comparison with controls. Interestingly, a slight increase in proliferation was found as well in the contralateral non-lesioned hemispheres. Moderate elevation of cell proliferation was found after induction of sham-lesions as well. The intensity of the reaction in the subependymal layer decreased in the following 8 weeks. Only a few scattered cells that originated from the subependymal layer had migrated over a short distance to adjacent brain tissue. We conclude that the reaction of the subependymal layer is (a) non-specific, as it is a response to any type of lesion, and (b) slowly decreases in time.

Experimental brain injury induces activation of neural stem cells in the forebrain subependyma

The subependymal zone (SEZ) of adult mammalians contains relatively quiescent neural stem cells that can be stimulated toward proliferation in response to specific stimuli. We used immunophenotypization to demarcate sharp boundaries of the SEZ and identify cell populations constituting the rat intact SEZ. Moreover, we studied the proliferation rates of SEZ cells under various experimental conditions that induced the lesion of the neighboring brain parenchyma or SEZ cells. Four groups of experimental animals included rats that were (1). mechanically injured, (2). intracerebrally injected with kainic acid, (3). treated with intracerebral injection of neurotoxic sodium nitroprusside, or (4). treated with intraperitoneal injection of cyclophosphamide. Animals were killed after 4 or 8 days. The number of SEZ proliferating cells was counted in coronal sections immunostained for proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine. Our results show that all types of injury induced activation of SEZ neural stem cells, evidenced by the increase of corresponding proliferation indices when compared with intact brains. The increase was detected not only in ipsilateral but also in contralateral (intact) SEZ. After mechanically induced trauma of the right cerebral hemisphere, the increase in the number of SEZ proliferative cells was observed after 8 days in the right cerebral ventricle. Injection of kainic acid induced early responses in SEZ cells that reached the highest values. Injury induced by sodium nitroprusside evoked early increase of PCNA, whereas bromodeoxyuridine increase was detected in SEZ at day 8. Cyclophosphamide activated SEZ proliferation after 4 days, and the level of proliferation indices remained approximately the same at day 8. Our data suggest that each type of brain injury induces a SEZ proliferative response with a specific temporal pattern.

Cell analysis with the new Leipzig high-energy ion nanoprobe

The high-energy ion nanoprobe LIPSION at the University of Leipzig has been in operation since 1998. The ultrastable, 3.5 MV SINLETRON accelerator supplies the H+ or He+ ion beam. A magnetic scanning system moves the focused beam across the sample. At present, a resolution of 41 +/- 4 nm in the low current mode and 300 nm at 5 pA can be achieved. The experimental chamber is equipped with electron-, energy dispersive X-ray-, and particle detectors. They can be used simultaneously to analyse the sample by means of PIXE (particle induced X-ray emission), RBS (Rutherford backscattering), and in the case of thin sections or monolayer samples STIM (scanning transmission ion microscopy). A goniometer allows the application of channeling measurements in single crystals in combination with these methods. In contrast to previous publication describing microbeam facility at LIPSION, the current biomedical research has concentrated on microscopy and tomography on chondrocytes in pig cartilages and fixed single endothelial cells (HUVEC). For the irradiation of single living cells, an external beam facility with irradiation platform, fast beamgate and mini-Petri dishes is under construction.

Radiation-induced bystander effects. Mechanisms, biological implications, and current investigations at the Leipzig LIPSION facility

BACKGROUND

The bystander effect is a relatively new area of radiobiological research, which is aimed at studying post-radiation changes in neighboring non-hit cells or tissues. The bystander effect of ionizing irradiation is important after low-dose irradiation in the range of up to 0.2 Gy, where a higher incidence of stochastic damage was observed than was expected from a linear-quadratic model. It is also important when the irradiation of a cell population is highly non-uniform.

OBJECTIVE

This review summarizes most of the important results and proposed bystander effect mechanisms as well as their impact on theory and clinical practice. The literature, in parts contradictory, is collected, the main topics are outlined, and some basic papers are described in more detail. In order to illustrate the microbeam technique, which is considered relevant for the bystander effect research, the state of the Leipzig LIPSION nanoprobe facility is described.

RESULTS

The resistance of a radiation-induced bystander effect is now generally accepted. The current state of knowledge on it is summarized here. Several groups worldwide are working on understanding its different aspects and its impact on radiobiology and radiation protection.

CONCLUSION

The observation of a bystander effect has posed many questions, and answering them is a challenging topic for radiobiology in the future.

Beta1-integrin and IL-1alpha expression as bystander effect of medium from irradiated cells: the pilot study

Bystander effects have been proposed as a third action pathway of ionising radiation besides direct and indirect effects. The purpose of the study was to investigate whether expression of interleukin-1alpha (IL-1alpha) and beta1-integrin is elevated in bystander cells as a marker for bystander effects in comparison with classical markers such as the clonogenic assay, apoptosis and the presence of micronuclei. The hybrid cell line E.A. hy.926 obtained by fusion of HUVEC cells with the epithelial cell line A 459 was irradiated with 0-5 Gy. Bystander effects were established via medium transfer at 45 min and 4 h after irradiation from irradiated to nonirradiated cell populations. In order to exclude effects of the irradiated medium itself, irradiated medium only was also used for transfer to nonirradiated cells. Then, cells were fixed at 1, 2, 6, and 24 h after irradiation or medium transport and IL-1alpha and beta1-integrin were detected and evaluated. A higher number of beta1-integrin-positive cells was observed in both irradiated and bystander cell populations than in the control group at 1 and 24 h after irradiation with 1 Gy or medium transfer. Significantly higher numbers of IL-1alpha-positive cells were found at 1, 2, and 6 h after irradiation with 1 Gy or medium transfer as well as at 2 and 6 h after irradiation with 5 Gy or medium transfer. Clonogenic survival decreased dependently on the dose in irradiated cells but did not show any significant difference between the bystander cell populations and sham-irradiated cells. The irradiated medium itself did not have any effect. It is concluded that beta1-integrin and IL-1alpha expression may serve as more sensitive markers of post-irradiation responses in bystander cell populations than the classical radiobiological markers. Moreover, overexpression of beta1-integrin and IL-1alpha may induce increased susceptibility to inflammation of bystander cells.

Non-T cell activation linker (NTAL): a transmembrane adaptor protein involved in immunoreceptor signaling

A key molecule necessary for activation of T lymphocytes through their antigen-specific T cell receptor (TCR) is the transmembrane adaptor protein LAT (linker for activation of T cells). Upon TCR engagement, LAT becomes rapidly tyrosine phosphorylated and then serves as a scaffold organizing a multicomponent complex that is indispensable for induction of further downstream steps of the signaling cascade. Here we describe the identification and preliminary characterization of a novel transmembrane adaptor protein that is structurally and evolutionarily related to LAT and is expressed in B lymphocytes, natural killer (NK) cells, monocytes, and mast cells but not in resting T lymphocytes. This novel transmembrane adaptor protein, termed NTAL (non-T cell activation linker) is the product of a previously identified WBSCR5 gene of so far unknown function. NTAL becomes rapidly tyrosine-phosphorylated upon cross-linking of the B cell receptor (BCR) or of high-affinity Fcgamma- and Fc epsilon -receptors of myeloid cells and then associates with the cytoplasmic signaling molecules Grb2, Sos1, Gab1, and c-Cbl. NTAL expressed in the LAT-deficient T cell line J.CaM2.5 becomes tyrosine phosphorylated and rescues activation of Erk1/2 and minimal transient elevation of cytoplasmic calcium level upon TCR/CD3 cross-linking. Thus, NTAL appears to be a structural and possibly also functional homologue of LAT in non-T cells.

Apoptosis and bcl-2 expression in irradiated lungs and the effect of pentoxifylline

We measured number of bcl-2, apoptotic, neutrophil, and surfactant apoprotein D (SP-D) positive cells in irradiated rat lungs during different time points after the sublethal whole-thorax irradiation of rats. We also investigated the influence of pentoxifylline (PTX) therapy on these markers. Wistar rats were given 15 Gy thoracic irradiation and PTX (35 mg/kg) twice a week. Animals were examined histologically and imunohistochemically at intervals from 1-12 weeks. In non-treated rats compared with treated rats, bcl-2 expression was significantly inhibited from 4 weeks after irradiation. A higher apoptosis presence in non-treated rats from 4 weeks was found and apoptosis development in PTX-treated animals was delayed and started 8 weeks after irradiation. Similar differences were measured during neutrophil granulocytes examination. Neutrophil penetration in non-treated rats was found 5 weeks after irradiation in contrast to the RP onset of PTX-treated animals 8 weeks after irradiation. The number of SP-D positive cells in non-treated rats observed until 5 weeks after irradiation was higher than in the control group. PTX-treated animals expressed higher number of SP-D positive cells during the whole experiment than the control group. We suggest that apoptosis is linked to neutrophil granulocyte actions during the RP onset and that PTX-therapy causes diminished inflammation development.

[An animal model of Huntington's disease: the development of histopathological changes within the neurotoxic lesions of the striatum in long-term surviving rats]

The neurotoxic lesion of the rat brain, induced by stereotaxic infusion of the ibotenic (IA) or kainic (KA) acids, is a commonly used model of Huntington's disease (HD) in animal studies. Neurodegenerative process in HD develops for 10-20 years. However, the majority of studies related to the animal models of HD deal with only the several weeks surviving animals. For that reason, a detailed description of the development of histopathological changes in the striatum in the rat brain is presented in this study. Intrastriatal instillation of both, the IA or the KA causes the partial necrosis of the striatum, accompanied by a rarefaction of the neuropil. Owing to a rather low number of subsequently in situ proliferating glial cells, predominantly astrocytes, the whole process results in a shrinkage of the striatum compensated by an enlargement of the lateral brain ventricles. Although, the fully developed IA lesion is envisaged at 1 week and KA lesion at 3-4 weeks after the injection of neurotoxic acids, the degenerative process within the striatum develops in a rather long time -- at least 6 months. The only morphological observation that doesn't correlate to the findings from the HD patients, is the needle-track area, which is repaired by a conspicuous glial or glial-fibrotic scar. There is no substantial difference in the histopathological characteristics of both the neurotoxic acids used in our studies. However, if the IA must be applied into 3-4 sites in each hemisphere in comparison with only one injection of the KA, the use of KA is, from the morphological point of view, more suitable in relation to the number of artificial needle-track areas.

The dialysis of Ochratoxin A (OTA)

Standard dialysis did not result in a decrease of the OTA level in the blood serum of patients regularly treated by dialysis. Therefore, we examined the effect of dialysis on both OTA bound to the blood plasma proteins and free OTA. We carried out an in vivo experiment to determine OTA levels in the serum of patients in the terminal stage of chronic renal insufficiency (CHRI) before and after dialysis and also in the dialysate in which we did not find OTA. OTA bound to blood plasma proteins did not penetrate the dialysis membrane. In contrast, free OTA during an in vitro experiment with the identical dialyzer (as during the in vivo experiment), easily penetrated the same dialysis membrane.

The alveolar septal thickness and type II pneumocytes number in irradiated lungs, time expression and the effect of pentoxifylline

PURPOSE

We studied the relationship between type II pneumocytes number and alveolar septal thickness during different time after sublethal whole-thorax irradiation of rats and we investigated the influence of pentoxifylline (TNF-alpha inhibitor).

MATERIALS AND METHODS

Wistar rats were exposed to 15 Gy thoracic irradiation and pentoxifylline (35 mg/kg) twice a week. Lungs were examined histologically and immunohistochemically at intervals ranging from 1-12 weeks and alveolar septal thickness, number of type II pneumocytes (identified by immunoreactivity for cytokeratin 18), and neutrophile granulocytes were counted.

RESULTS

Significant increase of alveolar septal thickness and type II pneumocytes depletion 3 weeks after irradiation were found. Correlation of these markers was r = -0.759. Pentoxifylline significantly inhibits increased alveolar septal thickness without the influence on type II pneumocytes number. Neutrophil penetration started 5 weeks after irradiation in non-treated animals, 8 weeks after irradiation in PTX-treated rats.

CONCLUSIONS

We suggest that pneumocytes depletion is linked to increased vascular permeability, and pentoxifylline therapy does not influence on pneumocytes kinetics after irradiation.

Differential expression of the Ca2+ binding S100A6 protein in normal, preneoplastic and neoplastic colon mucosa

The expression of calcium-binding protein S100A6 was investigated in normal colon tissue, in colon adenomas and in colorectal carcinomas. Using an immunoblotting approach we detected four S100A6 variants with Mwt of 10 kDa and pI of 5.05 (isoform I), 5.15 (isoform II), 5.23 (isoform III) and 5.32 (isoform IV) that were differentially expressed in the analysed samples. The quantitative examination of S100A6 variant expression in 25 pairs of colorectal carcinoma and matched control mucosa proved a statistically significant increased abundance of S100A6 isoforms I (P = 0.004) and III (P = 0.025) in malignant tissue, and conversely, an increased level of S100A6 isoform IV in healthy tissue (P = 0.022). The expression of isoforms I and III and the loss of isoform IV were also observed in colon cancer cell lines. In addition, the immunohistochemical study of 16 primary colorectal carcinomas revealed both in the non-paired Student t-test and in the Mann Whitney test the statistically significant accumulation of S100A6 protein (P < 0.001) in the invasive margin of the tumour. The immunohistochemical analysis of S100A6 protein in polyps differing in clinical severity gave a strong staining that was maximal in dysplastic lesions. Thus, our results indicate a possible, statistically significant correlation (non-paired Student t-test P = 0.036) between S100A6 expression and colon carcinoma progression.

Protein abundance alterations in matched sets of macroscopically normal colon mucosa and colorectal carcinoma

Our current results, aimed at the detection of protein abundance alterations that could be associated with the process of colon tumorigenesis, are summarized. The matched sets of macroscopically normal colon mucosa and colorectal carcinoma were examined by a one- or two-dimensional electrophoretic approach and proteins were identified using immunoblotting or mass spectrometry. The following results were observed: The levels of liver fatty acid-binding protein, actin-binding protein/smooth muscle protein 22-alpha and cyclooxygenase 2 were downregulated in colorectal carcinoma compared to normal colon mucosa. Conversely, the expression of a novel variant of heat shock protein70 and several members of the S100 protein family of calcium-binding proteins (two isoforms of S100A9, S100A8, S100A11 and S100A6) were upregulated in transformed colon mucosa. Despite the variations of the levels of expression of given protein among analyzed samples, all quantitative changes were found to be statistically significant (Mann-Whitney test assuming p < or = 0.05). We conclude that the proteomic approach is useful for the study of complex biological events underlying the process of colorectal tumorigenesis.

Protein abundance alterations in matched sets of macroscopically normal colon mucosa and colorectal carcinoma

Our current results, aimed at the detection of protein abundance alterations that could be associated with the process of colon tumorigenesis, are summarized. The matched sets of macroscopically normal colon mucosa and colorectal carcinoma were examined by a one- or two-dimensional electrophoretic approach and proteins were identified using immunoblotting or mass spectrometry. The following results were observed: The levels of liver fatty acid-binding protein, actin-binding protein/smooth muscle protein 22-alpha and cyclooxygenase 2 were downregulated in colorectal carcinoma compared to normal colon mucosa. Conversely, the expression of a novel variant of heat shock protein70 and several members of the S100 protein family of calcium-binding proteins (two isoforms of S100A9, S100A8, S100A11 and S100A6) were upregulated in transformed colon mucosa. Despite the variations of the levels of expression of given protein among analyzed samples, all quantitative changes were found to be statistically significant (Mann-Whitney test assuming p < or = 0.05). We conclude that the proteomic approach is useful for the study of complex biological events underlying the process of colorectal tumorigenesis.

Protein abundance alterations in matched sets of macroscopically normal colon mucosa and colorectal carcinoma

Our current results, aimed at the detection of protein abundance alterations that could be associated with the process of colon tumorigenesis, are summarized. The matched sets of macroscopically normal colon mucosa and colorectal carcinoma were examined by a one- or two-dimensional electrophoretic approach and proteins were identified using immunoblotting or mass spectrometry. The following results were observed: The levels of liver fatty acid-binding protein, actin-binding protein/smooth muscle protein 22-alpha and cyclooxygenase 2 were downregulated in colorectal carcinoma compared to normal colon mucosa. Conversely, the expression of a novel variant of heat shock protein70 and several members of the S100 protein family of calcium-binding proteins (two isoforms of S100A9, S100A8, S100A11 and S100A6) were upregulated in transformed colon mucosa. Despite the variations of the levels of expression of given protein among analyzed samples, all quantitative changes were found to be statistically significant (Mann-Whitney test assuming p < or = 0.05). We conclude that the proteomic approach is useful for the study of complex biological events underlying the process of colorectal tumorigenesis.

Radiation pneumonitis: the model of interstitial edema

We used the measurement of the thickness of alveolar septa in the lungs in (C57BI/6xDBA/2)F1 mice irradiated locally in the area of the thorax with absorbed doses of 14, 16 and 18 Gy of gamma rays. The thickness of alveolar septa of the pulmonary tissue was measured using a computer image analysis. 24 weeks after irradiation we found a significant increase in the thickness of alveolar septa in direct relation to the dose within a range of 14 to 18 Gy. This indicator can be used for observation of the radioprotective and remedial interventions against the inception and the development of radiation pneumonitis.

The analysis of S100A9 and S100A8 expression in matched sets of macroscopically normal colon mucosa and colorectal carcinoma: the S100A9 and S100A8 positive cells underlie and invade tumor mass

The expression of calcium-binding protein S100A9 was investigated in 23 matched sets of colorectal carcinoma and normal colon mucosa using two-dimensional gel electrophoresis. We found that, from a group of 23 patients, the level of S100A9 protein, in comparison with matched normal colon mucosa, was significantly increased in malignant tissues of 16 patients (70%). Furthermore, an additional protein, identified by matrix-assisted laser desorption/ionization - mass spectrometry (MALDI-MS) as S100A8, exhibited an increased expression in the same specimens of malignant tissues as the S100A9 protein. The immunohistological analysis revealed the accumulation of S100A9 positive cells, macrophages and polymorphonuclear leukocytes along the invasive margin of colorectal carcinoma. The S100A8 protein was found to be produced in the same location. The possible participation of both proteins and, especially, its heterodimeric complex calprotectin in colorectal carcinoma regression could be taken into account.

The analysis of S100A9 and S100A8 expression in matched sets of macroscopically normal colon mucosa and colorectal carcinoma: the S100A9 and S100A8 positive cells underlie and invade tumor mass

The expression of calcium-binding protein S100A9 was investigated in 23 matched sets of colorectal carcinoma and normal colon mucosa using two-dimensional gel electrophoresis. We found that, from a group of 23 patients, the level of S100A9 protein, in comparison with matched normal colon mucosa, was significantly increased in malignant tissues of 16 patients (70%). Furthermore, an additional protein, identified by matrix-assisted laser desorption/ionization - mass spectrometry (MALDI-MS) as S100A8, exhibited an increased expression in the same specimens of malignant tissues as the S100A9 protein. The immunohistological analysis revealed the accumulation of S100A9 positive cells, macrophages and polymorphonuclear leukocytes along the invasive margin of colorectal carcinoma. The S100A8 protein was found to be produced in the same location. The possible participation of both proteins and, especially, its heterodimeric complex calprotectin in colorectal carcinoma regression could be taken into account.

The analysis of S100A9 and S100A8 expression in matched sets of macroscopically normal colon mucosa and colorectal carcinoma: the S100A9 and S100A8 positive cells underlie and invade tumor mass

The expression of calcium-binding protein S100A9 was investigated in 23 matched sets of colorectal carcinoma and normal colon mucosa using two-dimensional gel electrophoresis. We found that, from a group of 23 patients, the level of S100A9 protein, in comparison with matched normal colon mucosa, was significantly increased in malignant tissues of 16 patients (70%). Furthermore, an additional protein, identified by matrix-assisted laser desorption/ionization - mass spectrometry (MALDI-MS) as S100A8, exhibited an increased expression in the same specimens of malignant tissues as the S100A9 protein. The immunohistological analysis revealed the accumulation of S100A9 positive cells, macrophages and polymorphonuclear leukocytes along the invasive margin of colorectal carcinoma. The S100A8 protein was found to be produced in the same location. The possible participation of both proteins and, especially, its heterodimeric complex calprotectin in colorectal carcinoma regression could be taken into account.