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141.
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143.
Groblewska M Siewko M Mroczko B Szmitkowski M 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2012,50(1):12-19
Esophageal cancer (EC) is one of the most aggressive malignant tumors of the gastrointestinal tract. There are two distinct histological types of EC: esophageal squamous cell carcinoma and adenocarcinoma of the esophagus. Etiologic factors and the patterns of incidence of both subtypes are different. Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play an important role in esophageal carcinogenesis. Gellatinases MMP-2 and MMP-9 are able to degrade collagen IV from basement membranes and extracellular matrix which is related to tumor progression, including invasion, metastasis, growth and angiogenesis. It has been shown that increased expression of MMPs plays a crucial role in the development of several human malignancies, including esophageal cancer. The activity of MMPs is regulated by their endogenous natural inhibitors (TIMPs). Among these, the roles of TIMP-1 and TIMP-2 in EC development, tumor progression and formation of metastases have been most extensively characterized and best recognized. 相似文献
144.
The relationship between seedling growth and grain yield under drought conditions in maize and triticale genotypes 总被引:1,自引:0,他引:1
Maciej T. Grzesiak Izabela Marcińska Franciszek Janowiak Andrzej Rzepka Tomasz Hura 《Acta Physiologiae Plantarum》2012,34(5):1757-1764
The effects of drought stress on seedlings?? growth and grain yield of 13 single cross maize hybrids and 11 breeding lines and cultivars of spring triticale were studied in greenhouse and field experiments. In the field experiment, the drought susceptibility index (DSIGY) was calculated by determining the change in grain yield (GY) in conditions with two soil moisture levels (IR, irrigated; D, drought). In the greenhouse experiment the response to soil drought was evaluated using DSIDW, by determining changes in the dry weight (DW) of vegetative plant parts. Marked variations in GY and DW were observed among the studied genotypes. In control conditions, the GY and DW in drought-sensitive genotypes were higher compared to the drought-resistant ones; but in drought conditions, the decreases in GY and DW in resistant genotypes were smaller than in drought-sensitive ones. DSIGY and DSIDW revealed variations in the degree of drought tolerance among the examined maize and triticale genotypes. The values of DSIGY in the field experiment and DSIDW in the greenhouse experiment enabled a division of the studied genotypes into drought-resistant or -sensitive groups. A close correlation between DSIGY and DSIDW was found. The positive linear correlation and determination coefficients between DSIGY and DSIDW were statistically significant (P?=?0.05), being equal to R 2?=?0.614 (maize) and R 2?=?0.535 (triticale). The ranking of the studied genotypes based on DSIGY was in most cases consistent with the ranking based on DSIDW, which indicates that genetically conditioned drought tolerance is similar for plants in the seedling and reproductive growth stages or may at least partly have a common genetic background. 相似文献
145.
Cadmium-induced changes in genomic DNA-methylation status increase aneuploidy events in a pig Robertsonian translocation model 总被引:1,自引:0,他引:1
Inglot P Lewinska A Potocki L Oklejewicz B Tabecka-Lonczynska A Koziorowski M Bugno-Poniewierska M Bartosz G Wnuk M 《Mutation research》2012,747(2):182-189
Although cadmium is a well-established human carcinogen, the mechanisms by which it induces cancer are poorly understood. It is suggested that cadmium-mediated carcinogenesis may include the modulation of gene expression and signal-transduction pathways, interference with antioxidant enzymes, inhibition of DNA repair and DNA methylation, and induction of apoptosis. Nevertheless, no predominant mechanism playing a role in metal-induced carcinogenesis has been reported. In the present study, we used a pig Robertsonian translocation model, which is a cross between a wild boar and domestic pig resulting in Robertsonian translocation (37,XX,der15;17 or 37,XY,der15;17), to determine the role of cadmium sulfate in the modulation of genomic DNA-methylation status and the induction of aneuploidy. We found a cadmium-mediated increase in aneuploidy within chromosome group A and C, but not within chromosome group D containing the translocated chromosome der15,17 which indicates that translocated chromosome is not more prone to chromosomal aberrations than are other chromosomes. We suggest that cadmium-induced aneuploidy (up to 5-μM concentration) may be mediated by global DNA hypermethylation as monitored with HPLC and 5-mdC immunostaining. In addition, the cyto- and genotoxic potential of cadmium was evaluated. Cadmium sulfate was able to induce apoptosis, inhibit cell-proliferative status and expression of nucleolar organizer regions (NORs), and increase oxidative DNA damage (8-oxoG content). 相似文献
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148.
Milena Wiech Maciej B. Olszewski Zuzanna Tracz-Gaszewska Bartosz Wawrzynow Maciej Zylicz Alicja Zylicz 《PloS one》2012,7(12)
Numerous p53 missense mutations possess gain-of-function activities. Studies in mouse models have demonstrated that the stabilization of p53 R172H (R175H in human) mutant protein, by currently unknown factors, is a prerequisite for its oncogenic gain-of-function phenotype such as tumour progression and metastasis. Here we show that MDM2-dependent ubiquitination and degradation of p53 R175H mutant protein in mouse embryonic fibroblasts is partially inhibited by increasing concentration of heat shock protein 70 (HSP70/HSPA1-A). These phenomena correlate well with the appearance of HSP70-dependent folding intermediates in the form of dynamic cytoplasmic spots containing aggregate-prone p53 R175H and several molecular chaperones. We propose that a transient but recurrent interaction with HSP70 may lead to an increase in mutant p53 protein half-life. In the presence of MDM2 these pseudoaggregates can form stable amyloid-like structures, which occasionally merge into an aggresome. Interestingly, formation of folding intermediates is not observed in the presence of HSC70/HSPA8, the dominant-negative K71S variant of HSP70 or HSP70 inhibitor. In cancer cells, where endogenous HSP70 levels are already elevated, mutant p53 protein forms nuclear aggregates without the addition of exogenous HSP70. Aggregates containing p53 are also visible under conditions where p53 is partially unfolded: 37°C for temperature-sensitive variant p53 V143A and 42°C for wild-type p53. Refolding kinetics of p53 indicate that HSP70 causes transient exposure of p53 aggregate-prone domain(s). We propose that formation of HSP70- and MDM2-dependent protein coaggregates in tumours with high levels of these two proteins could be one of the mechanisms by which mutant p53 is stabilized. Moreover, sequestration of p73 tumour suppressor protein by these nuclear aggregates may lead to gain-of-function phenotypes. 相似文献
149.
Wee Ling Heng Chong Hee Lim Ban Hock Tan Maciej Piotr Chlebicki Winnie Hui Ling Lee Tracy Seck Yeong Phang Lim 《PloS one》2012,7(12)
Background
In February 2012, the National Cardiovascular Homograft Bank (NCHB) became the first tissue bank outside of North America to receive accreditation from the American Association of Tissue Banks. From 2008 to 2009, NCHB had been decontaminating its cardiovascular homografts with penicillin and streptomycin. The antibiotic decontamination protocol was changed in January 2010 as amikacin and vancomycin were recommended, in order to cover bacteria isolated from post-recovery and post- antibiotic incubation tissue cultures.Aim
The objective of this study is to determine the optimal incubation conditions for decontamination of homografts by evaluating the potencies of amikacin and vancomycin in different incubation conditions. Retrospective reviews of microbiological results were also performed for homografts recovered from 2008 to 2012, to compare the effectiveness of penicillin-streptomycin versus the amikacin-vancomycin regimens.Methods
Based on microbiological assays stated in United States Pharmacopeia 31, potency of amikacin was evaluated by turbidimetric assay using Staphylococcus aureus, while vancomycin was by diffusion assay using Bacillus subtilis sporulate. Experiments were performed to investigate the potencies of individual antibiotic 6-hours post incubation at 4°C and 37°C and 4°C for 24 hours, after the results suggested that amikacin was more potent at lower temperature.Findings
Tissue incubation at 4°C for 24 hours is optimal for both antibiotics, especially for amikacin, as its potency falls drastically at 37°C.Conclusion
The decontamination regimen of amikacin-vancomycin at 4°C for 24 hours is effective. Nevertheless, it is imperative to monitor microbiological trends closely and evaluate the efficacy of current antibiotics regimen against emerging strains of micro-organisms. 相似文献150.
Piotr H. Ma?eckiWojciech Rypniewski Maciej SzymańskiJan Barciszewski Arne Meyer 《Biochimica et Biophysica Acta - Proteins and Proteomics》2012,1824(2):334-338
The crystal structure of the ribosome inhibiting protein Mistletoe Lectin I (ML-I) derived from the European mistletoe, Viscum album, in complex with kinetin has been refined at 2.7 Å resolution. Suitably large crystals of ML-I were obtained applying the counter diffusion method using the Gel Tube R Crystallization Kit (GT-R) on board the Russian Service Module on the international space station ISS within the GCF mission No. 6, arranged by the Japanese aerospace exploration agency (JAXA). Hexagonal bi-pyramidal crystals were grown during three months under microgravity. Before data collection the crystals were soaked in a saturated solution of kinetin and diffraction data to 2.7 Å were collected using synchrotron radiation and cryogenic techniques. The atomic model was refined and revealed a single kinetin molecule in the ribosome inactivation site of ML-I. The complex demonstrates the feasibility of mistletoe to bind plant hormones out of the host regulation system as part of a self protection mechanism. 相似文献