11 research outputs found

    Can high dose rates used in cancer radiotherapy change therapeutic effectiveness?

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    Current cancer radiotherapy relies on increasingly high dose rates of ionising radiation (100–2400 cGy/min). It is possible that changing dose rates is not paralleled by treatment effectiveness. Irradiating cancer cells is assumed to induce molecular alterations that ultimately lead to apoptotic death. Studies comparing the efficacy of radiation-induced DNA damage and apoptotic death in relation to varying dose rates do not provide unequivocal data. Whereas some have demonstrated higher dose rates (single dose) to effectively kill cancer cells, others claim the opposite. Recent gene expression studies in cells subject to variable dose rates stress alterations in molecular signalling, especially in the expression of genes linked to cell survival, immune response, and tumour progression. Novel irradiation techniques of modern cancer treatment do not rely anymore on maintaining absolute constancy of dose rates during radiation emission: instead, timing and exposure areas are regulated temporally and spatially by modulating the dose rate and beam shape. Such conditions may be reflected in tumour cells’ response to irradiation, and this is supported by the references provided

    Jerzy Andrzejewski

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    Dynamika systematycznego wzrostu, nowoczesna przestrzeń intelektu, labirynt znaków, magia zaangażowanych w swoją pracę ludzi z pasją – to tylko kilka haseł, które przychodzą na myśl, kiedy chcemy przywołać nazwę Biblioteki Uniwersytetu Łódzkiego i 70 lat jej historii. Łódź przed dwoma wiekami powstawała z tradycji niejednorodnych, i podobnie powstawał – jako mozaika różnych treści intelektualnych – Uniwersytet Łódzki

    VDR gene single nucleotide polymorphisms and their association with risk of oral cavity carcinoma

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    Vitamin D3 (1,25(OH)2D3 (1,25-dihydroxyvitamin D3)) is a hormone playing a crucial role in numerous biological processes in the human body, including induction and control of cell proliferation and differentiation. Numerous data relate the vitamin D3 level with various types of cancer. It has been suggested that SNPs in the vitamin D3 receptor (VDR) gene might influence both the risk of cancer occurrence and cancer progression. The aim of this study was to search for genetic correlations between individual SNPs in the VDR gene and the risk of oral cavity carcinoma. Two SNPs were selected based on the literature and our previous results. Seventy-three patients with squamous cell carcinoma of the head and neck and one hundred control subjects were investigated. Two SNPs in the VDR gene were genotyped in minisequencing reactions followed by capillary electrophoresis. Hardy-Weinberg equilibrium (HWE), the χ2 test and logistic regression were used for statistical analysis. The SNP rs2238135 in the VDR gene displayed statistical differences in frequency between the tested groups (p=0,0007). Furthermore, the G/C genotype of the rs2238135 in the VDR gene was characterized by a 3.16 fold increased risk of oral cavity carcinoma. The obtained results provide evidence for a genetic association between rs2238135 in the VDR gene and the occurrence and risk of oral cavity cancer


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    Abstract. Radiation-induced bystander effects occur in cells that are not directly irradiated but that communicate with irradiated cells via secreted into culture medium soluble factors or gap junction. This effect induces in irradiated and neighboring cells persistent long-term changes that result in delayed death or genomic instability leading to neoplastic transformation. Non-irradiated human normal lymphocytes were incubated in a medium transferred from irradiated another samples of lymphocytes (ICM -irradiation-conditioned medium). Immediately after replacement of the normal or conditioned medium antioxidant vitamins C or E were added. In lymphocytes incubated in a normal medium (control) or conditioned medium, with or without vitamins, the chromosomal damage and apoptosis were estimated. The results show that medium from irradiated cells (ICM) induces in normal lymphocytes micronuclei and condensation of chromatin characteristic of processes of apoptosis. Conditioned medium did not influence cell cycle division. Bystander effect-induced formation of micronuclei was inhibited by antioxidant vitamins C and E, but this had no effect on the induction of apoptosis. These observations suggest that antioxidant vitamins are able to modify radiation-induced bystander effect (by preventing the increase in micronuclei), without inhibiting elimination of damaged cells via apoptosis. This finding could have significant implication for estimating risks of radiation exposure

    Modulatory effects of the antioxidant ascorbic acid on the direct genotoxicity of doxorubicin in somatic cells of Drosophila melanogaster

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    In this study two different crosses involving the wing cell markers mwh and flr³ (standard (ST) cross and high bioactivation (HB) cross, the latter being characterized by a high constitutive level of cytochrome P450 which leads to an increased sensitivity to a number of promutagens and procarcinogens) were used to investigate the modulatory effects of ascorbic acid (AA) combined with the antitumor agent doxorubicin (DXR) in Drosophila melanogaster. We observed that the two different concentrations of AA (50 or 100 mM) had no effect on spots frequencies, while DXR treatments (0.2 or 0.4 mM) gave positive results for all types of spots, when compared to negative control. For marker-heterozygous (MH) flies, a protective effect was observed with the lower concentration of AA (50 mM) that was able to statistically decrease the frequency of spots induced by DXR (0.2 mM), while an enhanced frequency of spots induced by DXR was observed with the higher concentration of AA (100 mM), when compared to DXR treatment (p < 0.05). These results suggest that AA may interfere with free radicals generated by DXR and with other possible reactive metabolites. The efficiency of AA in protecting the somatic cells of D. melanogaster against mutation and recombination induced by DXR is dependent on the dose used and the protection is directly related to the activity of cytochrome P450 enzymes

    Thiamine prevents X-ray induction of genetic changes in human lymphocytes in vitro.

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    The effects of thiamine (vitamin B1) on the level of spontaneous or radiation-induced genetic changes in human lymphocytes in vitro were studied. Cultured lymphocytes were exposed to increasing concentrations of thiamine (0-500 μg/ml) and irradiated with X-rays. The DNA damage was estimated as the frequency of micronuclei and apoptotic or necrotic morphological changes in fixed cells. The results show that thiamine alone did not induce genetic changes. A significant decrease in the fraction of apoptotic and necrotic cells was observed in lymphocytes irradiated in the presence of vitamin B1 at concentrations between 1-100 μg/ml compared to those irradiated in the absence of thiamine. Vitamin B1 at 1 and 10 μg/ml decreased also the extent of radiation-induced formation of micronuclei. Vitamin B1 had no effect on radiation-induced cytotoxicity as measured by nuclear division index. The results indicate that vitamin B1 protects human cells from radiation-induced genetic changes


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    Представленный текст является небольшим материалом к вопросу об исследованиях истории чтения и посвящён одному из видов предварительных заметок, какими являются рукописные авторские дедикации. Состоит он из четырёх основных частей. Первая из них это обзор исследовательских работ по рукописным авторским дедикациям в польской письменности. Следующая часть рассматривает историю книжной коллекции Яна Кароля Корвин-Коха- новского, которая попала в коллекцию библиотеки Лодзинского университета. Очередная часть представляет 250 авторских дедикаций, которые украшают вышеупомянутую библиотеку книг. Последняя же часть содержит перепечатку нескольких выбранных дедикаций. Дополнением всего является индекс всех авторов, которые посвящали свои книги