Gamma-radiation-induced damage of chicken myosin and actin

The single 60Co gamma radiation-induced damage of purified chicken myosin and actin in N2O saturated solution is dose dependent protein cross-linking. The differences in myosin and actin conformation and Mm do not influence the type of radiation-induced damage, but they influence the extent of radiation-induced damage, judged by the lower cross linking of fibrillar myosin compared to actin. The radiolytic behavior of myosin and actin in purified forms is different from their radiolysis in intact muscle, according to the absence of protein fragmentation in the former. The results confirm that industrially sterilized meat may contain significant amount (25- 35%) of structurally altered proteins.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Verbal violence in plays by Harold Pinter and Peter Handke Вербальное насилие в драматическом творчестве Гарольда Пинтера и Петера Хандке

Докторска дисертација Вербално насиље у драмском стваралаштву Харолда Пинтера и Петера Хандкеа обухвата истраживање начина употребе и функције вербалног насиља у изабраним драмским текстовима Харолда Пинтера и Петера Хандкеа. Оба писца у средиште својих драма стављају језик и сагледавају начине контроле човека, јунаци бивају преображени, уништени и присиљени на вербалне калупе који указују на утицаје владајуће идеологије на драмску праксу. Осветљава се Пинтеров и Хандкеов песимистичан поглед на човекову људскост и могућност да појединац остане слободан када се суочи с вербалном принудом, као и њихово упозорење да је човек постао затвореник свог говора. Вербална агресија у њиховим делима бива усмерена против публике и драмских ликова, њом се обликује стварност док је критичко мишљење немогуће, замењено је аутоматским дискурсом чиме је онемогућена самосвојност. У складу са овим сазнањем испитује се тематска повезаност Хандкеових и Пинтерових драма и указује се човекова подређеност кроз наметнуте језичке структуре. Потврдиће се хипотеза да језик затвара у своја правила и приморава да поштујемо та правила, његове форме и ограничења. Закључићемо да оба писца показују забринутост због немогућности остваривања саобраћања и односа међу људима. Упркос протесту против друштва и вербалног насиља, ови драмски писци не искључују себе и сатирично се односе према таквом животу. Са ликовима деле осећај угрожености, те постају носиоци њихових тежњи и реализатори идеја. Стога се и ми као публика осећамо угрожено и доживљавамо драме кроз сву неизвесност живљења и тешко искушење. Јунаци разоткривају стварност, али и немогућност њене промене. Њихове драме на неки начин постају наша иницијација – пружају нам јаснији увид и извесни осећај препорода.The doctoral dissertation Verbal Violence in Plays by Harold Pinter and Peter Handke includes research into the use and function of verbal violence in selected plays by Harold Pinter and Peter Handke. Focusing on language in plays by Pinter and Handke forms of human control are explored, where the heroes are transformed, destroyed and forced into verbal molds that indicate the influences of the ruling ideology on dramatic practice. Pinter and Handke's pessimistic view of humanity and the possibility of an individual remaining free when faced with verbal violence will be illuminated, as well as their warning that man has become a prisoner of his speech. Verbal aggression in their works is directed against the audience and dramatic characters, it shapes reality while critical thinking is impossible, it is replaced by automatic discourse, which prevents independence. In accordance with this knowledge, the thematic connection of Handke's and Pinter's plays is examined, where, above all, human subordination is indicated through imposed linguistic structures. The hypothesis that language encloses individuals in its rules and forces us to respect those rules, language forms and restrictions will be confirmed. It will be concluded that both writers show concern about the impossibility of establishing communication and relationships between people. Despite the protest against society and verbal violence, these playwrights do not exclude themselves and are satirical about such life. They share a sense of threat with the characters, and become the bearers of their aspirations and the implementers of ideas. Therefore, we as an audience feel threatened and experience plays through all the uncertainty of life and heavy temptation. The heroes reveal reality, but also the impossibility of changing it. In a way, their plays become our initiation – they give us a clearer insight and a certain feeling of rebirth

Effect of different types of stress on adrenal gland parameters and adrenal hormones in the blood serum of male Wistar rats

In the present study, we examined gross changes in the mass of whole adrenal glands and that of the adrenal cortex and medulla in mature male Wistar rats subjected to three different stress types: acute, chronic, and combined, i.e., chronic followed by acute stress. These parameters were correlated with adrenal activity as judged from serum levels of corticosterone and catecholamine, respectively, as well as with serum levels of ACTH and glucose. Under all three conditions, we observed bilaterally asymmetric and stress-type-independent hypertrophy of whole adrenals, as well as adrenal cortices and medullas. Under acute and combined stress, adrenal hypertrophy was followed by increase of adrenal hormones in the blood serum. However, under chronic stress, both cortical and medullar activities as judged from low or unaltered levels of the respective hormones and glucose were compromised and disconnected from the input signal of ACTH. Since all of the studied adrenal activities could be restored by subsequent acute stress, it is concluded that chronic isolation can be viewed as partly maladaptive stress with characteristics resembling stress resistance rather than the stress exhaustion stage of the general adaptation syndrome

Redox-sensitive transcription factor NFkB in brain of stressed wistar rats

Neuroendocrine stress (NES) causes stress-hormones increase and alters balance of intracellular reactive oxygen species (ROS) leading to vulnerability of brain neurons. Prolonged alterations of cell redox milieux may also lead to altered expression of redox sensitive transcription factors, such as NFκB, resposible for brain cell protection. In the presented study NFκB p65 (NFκB) levels were determined in hippocampus and brain cortex of Wistar male rats.exposed to stress of different duration The cytosolic NFκB level was unchanged in acute stress (A, 2h), but significantly down-regulated in either chronic (C,21-day) or combined (C+A) stress. The depletion of NFκB from cell cytosol probably reflected its nuclear translocation and decoupling from the repressive action of glucocorticoid receptor. Through initially protective, NFkB overactivity may lead to accumulation of toxic H2O2 and compromise brain cell capacity to restore homeostasis.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Independent associations of childhood and current socioeconomic status with risk of self-reported doctor-diagnosed arthritis in a family-medicine cohort of North-Carolinians

Most experimental models, including cell culture studies, have demonstrated that over-expression of manganese superoxide dismutase (MnSOD) in cells bearing a carcinoma phenotype has anti-proliferative and tumour suppression characteristics. In contrast, when cervical carcinoma biopsies express MnSOD, there is a poor prognosis and resistance to radiation therapy. The results herein indicate that human cervical adenocarcinoma (HeLaS3) cells have increased MnSOD activity (up to 50 % of the total SOD activity) due to low expression of its repressor p53 and a high level of oxidative stress arising from the cell culture conditions. High MnSOD activity may be related to I-IcLaS3 cell radioresistance. illustrated by a high IC50 of 3.4 Gy and by a relatively high level of cell viability after gamma irradiation. In contrast to MnSOD activity, cytosolic CuZnSOD activity decreased after ionising radiation. The catalase (Cat) activity was unchanged. IR also increased the nitric oxide synthase (NOS) activity. Such conditions lead to increased concentrations of the superoxide radical, hydrogen peroxide and NO, which together may be responsible for the decreased expression of NF-B-K and unaltered Cat activity. Therefore, the disturbed redox balance within HeLaS3 cells may be responsible for the cytotoxicity observed at higher irradiation doses. It could be concluded that inhibition of the CuZrISOD activity may be an important target for the selective killing of radioresistant cancer cells

Antioxidant enzymes expression in liver of stressed wistar rat

The antioxidant enzymes (AOEs) expression was studied in Wistar rat liver under two types of stress: acute (immobilization) and chronic (isolation). The acute stress induced increase in blood corticosterone (CORT) and glucose (GLU), but decreased AOEs expression, and such conditions may result in oxidative stress. In contrast to acute stress, in chronic stress conditions, when both CORT and GLU were low, the AOEs expression was markedly induced. This increase in MnSOD, CuZnSOD, and catalase exhibited similar trend implying efficient detoxification of O2 .- and H2O2.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Adjuvant antiproliferative and cytotoxic effect of aloin in irradiated HeLaS3 cells

Naturally occurring phytoanthracycline, aloin, was used to radiosensitize HeLaS3 human cervix carcinoma cells. The results indicated that the cytotoxic adjuvant effect of aloin was synergistic with IR at all drug concentrations and comparable to the cytotoxicity of 5-10Gy IR alone. Radiosensitization of HeLaS3 cells was achieved by 60µM aloin which reduced IC50 dose of IR from 3.4- to 2Gy. The cell damage by both agents compromised cell capacity to conduct programmed cell death by apoptosis, and led to the synergic cytotoxic cell death by necrosis.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Gamma-radiation induced agglomeration of chicken muscle myosin and actin

Radiolytic behaviour of the major vertebrate muscle proteins: fibril Jar myosin (rnolar mass, M-m = 520,000 g/mol) and filament fortning actin (M-m = 42,050 g/mol) was studied using a SDS-polyacrylamide gel electrophoresis and quantified by high precision laser-densitometry. In order to study the OH radical contribution to the radiation damage, purified chicken myosin and actin (4 muM) were prepared in N2O saturated solution and irradiated with 1-3 kGy at Co-60 gamma source. With respect to changes in the molecular mass, the only observed myosin and actin damage was dose dependent agglomeration of proteins. The corresponding radiation chemical yields of 5 x 10(-8) mol J(-1) and 6.3 x 10(-8) mol J(-1) were obtained for myosin and actin, respectively. This result confirmed that only the radiation-induced agglomeration is initiated with the reaction of the OH radical even in the situation where the OH radical concentration produced exceeds the protein concentration 500 times, thus enabling the multi-radical attack to occur

Superoxide dismutases in radioresistant PC-3 human prostate carcinoma cells

The molecular mechanism of gamma-ionizing radiation (IR) resistance of human prostate cancer cells PC-3 is not known. Since low-LET-IR effects are primarily achieved through generation of reactive oxygen species (ROS), IR-induced expression of ROSmetabolizing antioxidant enzymes, Mn- and CuZn-superoxide dismutase (Mn- and CuZnSOD) and catalase (CAT), and their upstream regulator transcription factor NFκB was followed. Significant elevation of both SODs was found in cells irradiated with 10- and 20 Gy, while CAT and NFkB expression was unchanged. Since, such conditions lead to accumulation of H2O2, it is concluded that radioresistance of PC-3 cells may emerge from positive feed-forward vicious circle established between H2O2 activation of NFκB and elevated MnSOD activity.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Superoxide dismutases and p53 protein levels in blood cells of breast cancer patients

Purpose: Radiation treatment of breast cancer (BC) often results in post-therapy complications. The undesired sequelae could be avoided by the diagnostic screening of biomarkers for prediction of ionizing radiation (IR)-linked injury of healthy tissues. Patients and methods: The expression of antioxidative defence enzymes CuZn- and Mn-superoxide dismutase (CuZnSOD, MnSOD) and tumor suppressor protein p53 was measured in blood cells of 19 women with BC (age groups 30-45 and 46-60 years) and of the respective controls. The proteins were detected by specific immunostaining and quantified by laser-scanning densitometry. Results: Constitutive expression of CuZnSOD was significantly elevated in the group of BC patients (up to 254 arbitrary units, AU/mL) relative to the control group (105-130 AU/mL). The constitutive expression of MnSOD was elevated (up to 94 AU/mL) in the group of BC patients relative to the controls (53-56 AU/mL). p53 was also constitutively more expressed in BC patients (35-42 AU/mL) than in controls (32-33 AU/mL). Both MnSOD and p53 were inducible by 60Co gamma-ray IR (up to 170 AU/mL and 51 AU/mL, respectively) in the BC patient group. The levels of IR-induced p53 correlated inversely with MnSOD levels. Conclusion: The constitutive expression of all 3 proteins could be a useful biomarker for the presence of BC, but only MnSOD overexpression may be the predictive biomarker for selection of BC patients that would be less susceptible to IR-linked complications. © 2004 Zerbinis Medical Publications