60Co-γ Radiation Alters Developmental Stages of Zeugodacus cucurbitae (Diptera: Tephritidae) Through Apoptosis Pathways Gene Expression.

Radiation is considered as a promising insect pest control strategy for minimizing postharvest yield losses. Among various techniques, irradiation is a method of choice as it induces lethal biochemical or molecular changes that cause a downstream cascade of abrupt physiological abnormalities at the cellular level. In this study, we evaluated the effect of 60Co-γ radiation on various developmental stages of Zeugodacus cucurbitae Coquillett and subsequent carry-over effects on the progeny. For this purpose, we treated eggs with 30- and 50-Gy radiation doses of 60Co-γ. We found that radiation significantly affected cellular antioxidants, insect morphology, and gene expression profiles. Our results indicate that in response to various doses of irradiation reactive oxygen species, catalase, peroxidase, and superoxide dismutase activities were increased along with a significant increase in the malondialdehyde (MDA) content. We observed higher mortality rates during the pupal stage of the insects that hatched from irradiated eggs (50 Gy). Furthermore, the life span of the adults was reduced in response to 50 Gy radiation. The negative effects carried over to the next generation were marked by significantly lower fecundity in the F1 generation of the irradiation groups as compared to control. The radiation induced morphological abnormalities at the pupal, as well as the adult, stages. Furthermore, variations in the gene expression following irradiation are discussed. Taken together, our results signify the utility of 60Co-γ radiation for fruit fly postharvest management.

The effect of computed tomography on oxidative stress level and some antioxidant parameters.

BACKGROUND: X-rays are defined as ionizing radiation and hydrolyze the water, causing free radical formation. Oxidative stress is the damage that occurs in cells due to the lack of antioxidants, which detoxifies them, with the increased production of free radicals that occur during normal cellular metabolism. PURPOSE: To examine the acute effects of computed tomography (CT), i.e. ionizing radiation, on oxidative stress and antioxidant defense mechanisms. MATERIAL AND METHODS: The study included a total of 53 patients that were selected among the patients that underwent non-contrast full-body CT. Malondialdehyde (MDA) and reduced glutathione (GSH) levels and superoxide dismutase (SOD) and catalase (CAT) activities were investigated in blood samples taken from patients. RESULTS: The post-scan levels of MDA increased significantly while the post-scan levels of GSH, SOD, and CAT decreased significantly compared to their pre-scan levels. CONCLUSION: CT, which is a widely used X-ray imaging technique and has numerous known side effects, was found to increase the levels of MDA, which is an indicator of oxidative stress, and to decrease the levels of some antioxidants including GSH, SOD, and CAT.

Prophylactic application of laser light restores L-FABP expression in the livers of rats submitted to partial ischemia.

OBJECTIVES: The objective of the present study was to evaluate the protective effect of pre-conditioning treatment with laser light on hepatic injury in rats submitted to partial ischemia using mitochondrial function and liver fatty acid binding protein as markers. METHODS: Rats were divided into four groups (n=5): 1) Control, 2) Control + Laser, 3) Partial Ischemia and 4) Partial Ischemia + Laser. Ischemia was induced by clamping the hepatic pedicle of the left and middle lobes of the liver for 60 minutes. Laser light at 660 nm was applied to the liver immediately prior to the induction of ischemia at 22.5 J/cm2, with 30 seconds of illumination at five individual points. The animals were sacrificed after 30 minutes of reperfusion. Blood and liver tissues were collected for analysis of mitochondrial function, determination of malondialdehyde and analysis of fatty acid binding protein expression by Western blot. RESULTS: Mitochondrial function decreased in the Partial Ischemia group, especially during adenosine diphosphate-activated respiration (state 3), and the expression of fatty acid binding protein was also reduced. The application of laser light prevented bioenergetic changes and restored the expression of fatty acid binding protein. CONCLUSION: Prophylactic application of laser light to the livers of rats submitted to partial ischemia was found to have a protective effect in the liver, with normalization of both mitochondrial function and fatty acid binding protein tissue expression.

Prophylactic application of laser light restores L-FABP expression in the livers of rats submitted to partial ischemia

OBJECTIVES: The objective of the present study was to evaluate the protective effect of pre-conditioning treatment with laser light on hepatic injury in rats submitted to partial ischemia using mitochondrial function and liver fatty acid binding protein as markers. METHODS: Rats were divided into four groups (n=5): 1) Control, 2) Control + Laser, 3) Partial Ischemia and 4) Partial Ischemia + Laser. Ischemia was induced by clamping the hepatic pedicle of the left and middle lobes of the liver for 60 minutes. Laser light at 660 nm was applied to the liver immediately prior to the induction of ischemia at 22.5 J/cm2, with 30 seconds of illumination at five individual points. The animals were sacrificed after 30 minutes of reperfusion. Blood and liver tissues were collected for analysis of mitochondrial function, determination of malondialdehyde and analysis of fatty acid binding protein expression by Western blot. RESULTS: Mitochondrial function decreased in the Partial Ischemia group, especially during adenosine diphosphate-activated respiration (state 3), and the expression of fatty acid binding protein was also reduced. The application of laser light prevented bioenergetic changes and restored the expression of fatty acid binding protein. CONCLUSION: Prophylactic application of laser light to the livers of rats submitted to partial ischemia was found to have a protective effect in the liver, with normalization of both mitochondrial function and fatty acid binding protein tissue expression.

Comparison of the trapping effect and antioxidant enzymatic activities using three different light sources in cockchafers.

Light traps have been widely used for controlling underground pests. However, very little is known regarding the relationship between trapping effect and antioxidant enzymatic activities using light irradiation in underground pests. Thus, we determined the trapping effect of three light sources of the frequoscillation pest-killing lamp on two species of cockchafers, Serica orientalis Motschulsky (Coleoptera: Melolonthidae) and Anomala corpulenta Motschulsky (Coleoptera: Rutelidae), and evaluated the effect of the same three light sources on the activities of their antioxidant enzymes. The catches of S. orientalis were significantly higher compared to A. corpulenta using light source A in peanut fields in China. After irradiation by light source A, the malondialdehyde (MDA) contents and activities of superoxide dismutase (SOD) and glutathione S-transferases (GST) in S. orientalis were significantly and marginally significantly lower compared to A. corpulenta. Taken together, these results indicated a weaker antioxidant enzyme activity response to light stress and a larger quantity of trapping catches using light irradiation in cockchafers. Thus, we proposed a potential negative relationship between trapping effect and antioxidant enzymatic activities in response to light irradiation in cockchafers.

Acute effects of low-level laser therapy (660 nm) on oxidative stress levels in diabetic rats with skin wounds.

BACKGROUND: Laser therapy influences oxidative stress parameters such as the activity of antioxidant enzymes and the production of reactive oxygen species. OBJECTIVE: To analyze the effects of low-level laser therapy on oxidative stress in diabetics rats with skin wounds. METHODS: Thirty-six animals were divided into 4 groups: NDNI: non-diabetic rats with cutaneous wounds that not received laser therapy; NDI: non-diabetic rats with cutaneous wounds that received laser therapy; DNI: diabetic rats with skin wounds who did not undergo laser therapy; DI: rats with diabetes insipidus and cutaneous wounds and received laser therapy. The animals were treated with LLLT (660 nm, 100 mW, 6 J/cm, spot size 0.028 cm). On the day of killing the animals, tissue-wrapped cutaneous wounds were collected and immediately frozen, centrifuged, and stored to analyze malondialdehyde (MDA) levels. RESULTS: Significant difference was observed within the groups of MDA levels (ANOVA, p = 0.0001). Tukey's post-hoc test showed significantly lower values of MDA in irradiated tissues, both in diabetic and non-diabetic rats. ANOVA of the diabetic group revealed a significant difference (p < 0.01) when all groups, except NDI and DI, were compared. CONCLUSIONS: LLLT was effective in decreasing MDA levels in acute surgical wounds in diabetic rats.

The apoptotic effect and the plausible mechanism of microwave radiation on rat myocardial cells.

Microwaves may exert adverse biological effects on the cardiovascular system at the integrated system and cellular levels. However, the mechanism underlying such effects remains poorly understood. Here, we report a previously uncharacterized mechanism through which microwaves damage myocardial cells. Rats were treated with 2450 MHz microwave radiation at 50, 100, 150, or 200 mW/cm(2) for 6 min. Microwave treatment significantly enhanced the levels of various enzymes in serum. In addition, it increased the malondialdehyde content while decreasing the levels of antioxidative stress enzymes, activities of enzyme complexes I-IV, and ATP in myocardial tissues. Notably, irradiated myocardial cells exhibited structural damage and underwent apoptosis. Furthermore, Western blot analysis revealed significant changes in expression levels of proteins involved in oxidative stress regulation and apoptotic signaling pathways, indicating that microwave irradiation could induce myocardial cell apoptosis by interfering with oxidative stress and cardiac energy metabolism. Our findings provide useful insights into the mechanism of microwave-induced damage to the cardiovascular system.

Modulation of wireless (2.45 GHz)-induced oxidative toxicity in laryngotracheal mucosa of rat by melatonin.

It is well known that oxidative stress induces larynx cancer, although antioxidants induce modulator role on etiology of the cancer. It is well known that electromagnetic radiation (EMR) induces oxidative stress in different cell systems. The aim of this study was to investigate the possible protective role of melatonin on oxidative stress induced by Wi-Fi (2.45 GHz) EMR in laryngotracheal mucosa of rat. For this purpose, 32 male rats were equally categorized into four groups, namely controls, sham controls, EMR-exposed rats, EMR-exposed rats treated with melatonin at a dose of 10 mg/kg/day. Except for the controls and sham controls, the animals were exposed to 2.45 GHz radiation during 60 min/day for 28 days. The lipid peroxidation levels were significantly (p < 0.05) higher in the radiation-exposed groups than in the control and sham control groups. The lipid peroxidation level in the irradiated animals treated with melatonin was significantly (p < 0.01) lower than in those that were only exposed to Wi-Fi radiation. The activity of glutathione peroxidase was lower in the irradiated-only group relative to control and sham control groups but its activity was significantly (p < 0.05) increased in the groups treated with melatonin. The reduced glutathione levels in the mucosa of rat did not change in the four groups. There is an apparent protective effect of melatonin on the Wi-Fi-induced oxidative stress in the laryngotracheal mucosa of rats by inhibition of free radical formation and support of the glutathione peroxidase antioxidant system.

Anti-ulcerogenic effect of aqueous propolis extract and the influence of radiation exposure.

PURPOSE: To study the effect of aqueous propolis extract (AEP) against indomethacin (Indo)-induced gastric ulcers in irradiated and non-irradiated rats. MATERIALS AND METHODS: Animals were irradiated at different radiation dose levels before the induction of ulcers. AEP was injected orally 1 hour before induction of gastric ulcers and the effects compared with those of lansoprazole (Lanso), which was used as a reference anti-ulcerogenic drug. RESULTS: Pretreatment of rats, either irradiated or non-irradiated, with AEP effectively protected against Indo-induced gastric ulceration. This was associated with a reduction in acid output and peptic activity and an increase in the secretion of mucin. The mucosal prostaglandin E(2) (PGE(2)) level was also increased. The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1ß) were suppressed to the same extent after treatment. Both propolis and Lanso were effective in reducing the number of gastric lesions as well as the plasma level of malondialdehyde (MDA). CONCLUSIONS: These findings indicate that the gastroprotective effect of AEP could be of value in the management of excessive gastric damage induced by radiation exposure.

Photosynthetic response of clusterbean chloroplasts to UV-B radiation: energy imbalance and loss in redox homeostasis between Q(A) and Q(B) of photosystem II.

The effects of ultraviolet-B (UV-B: 280-320 nm) radiation on the photosynthetic pigments, primary photochemical reactions of thylakoids and the rate of carbon assimilation (P(n)) in the cotyledons of clusterbean (Cyamopsis tetragonoloba) seedlings have been examined. The radiation induces an imbalance between the energy absorbed through the photophysical process of photosystem (PS) II and the energy consumed for carbon assimilation. Decline in the primary photochemistry of PS II induced by UV-B in the background of relatively stable P(n), has been implicated in the creation of the energy imbalance(.) The radiation induced damage of PS II hinders the flow of electron from Q(A) to Q(B) resulting in a loss in the redox homeostasis between the Q(A) to Q(B) leading to an accumulation of Q(A)(-). The accumulation of Q(A)(-) generates an excitation pressure that diminishes the PS II-mediated O(2) evolution, maximal photochemical potential (F(v)/F(m)) and PS II quantum yield (Φ(PS II)). While UV-B radiation inactivates the carotenoid-mediated protective mechanisms, the accumulation of flavonoids seems to have a small role in protecting the photosynthetic apparatus from UV-B onslaught. The failure of protective mechanisms makes PS II further vulnerable to the radiation and facilitates the accumulation of malondialdehyde (MDA) indicating the involvement of reactive oxygen species (ROS) metabolism in UV-B-induced damage of photosynthetic apparatus of clusterbean cotyledons.

900 MHz pulse-modulated radiofrequency radiation induces oxidative stress on heart, lung, testis and liver tissues.

Oxidative stress may affect many cellular and physiological processes including gene expression, cell growth, and cell death. In the recent study, we aimed to investigate whether 900 MHz pulse-modulated radiofrequency (RF) fields induce oxidative damage on lung, heart and liver tissues. We assessed oxidative damage by investigating lipid peroxidation (malondialdehyde, MDA), nitric oxide (NOx) and glutathione (GSH) levels which are the indicators of tissue toxicity. A total of 30 male Wistar albino rats were used in this study. Rats were divided randomly into three groups; control group (n = 10), sham group (device off, n = 10) and 900 MHz pulsed-modulated RF radiation group (n = 10). The RF rats were exposed to 900 MHz pulsed modulated RF radiation at a specific absorption rate (SAR) level of 1.20 W/kg 20 min/day for three weeks. MDA and NOx levels were increased significantly in liver, lung, testis and heart tissues of the exposed group compared to sham and control groups (p < 0.05). Conversely GSH levels were significantly lower in exposed rat tissues (p < 0.05). No significantly difference was observed between sham and control groups. Results of our study showed that pulse-modulated RF radiation causes oxidative injury in liver, lung, testis and heart tissues mediated by lipid peroxidation, increased level of NOx and suppression of antioxidant defense mechanism.

Exposure to gamma rays induces early alterations in skin in rodents: Mechanical, biochemical and structural responses.

In this study, the effect of gamma rays has been investigated on the normal rat skin using biomechanical, biochemical and histological techniques. Seventeen male Wistar albino rats were divided into two groups (control (n=7) and irradiated (n=10)). The irradiated group was treated with a (60)Co gamma source at a dose of 10Gy at room temperature. Skin biomechanics were measured with tensile test using biomaterial testing machine and maximum load, stiffness, energy absorption capacity, ultimate stress, ultimate strain and elastic modulus were calculated. In the irradiated group, energy, strain and toughness were significantly lower than in the control group (p<0.05). However, strength, displacement, stiffness, stress and elastic modulus were similar to that of the control group (p>0.05). Catalase (CAT) activities and the levels of malondialdehyde (MDA) in the skin of rats were measured using the biochemical methods. MDA levels significantly increased whereas CAT activities decreased in the irradiated group as compared with the control group (p<0.05). Diameters of collagen fibers were measured by transmission electron microscopy. There was no significant difference (p>0.05) between control and irradiated groups for collagen fiber diameter. Thickness of epidermis was significantly lower than the control group. There were no changes in the epidermis between the irradiated group and the control group ultrastructurally. The results of this study show that the gamma irradiation has a significant effect on normal healthy skin.

[The effect of microwave radiation on the levels of MDA and the activity of SOD of nasopharyngeal carcinoma cells].

OBJECTIVE: To study the effect of microwave radiation on the levels of malondialdehyde (MDIA) and activity of superoxide dismutase (SOD) of Nasopharyngeal carcinoma cells. METHOD: The experiment were divided into four groups included control, 10, 20 and 30 mW/cm2 groups. The methods, such as TBA colorimetric assay and modified NBT hydroxylamine method, were used to detect the effect of microwave radiation on the levels of MDA and activity of SOD of nasopharyngeal carcinoma cells. RESULT: With increase of microwave radiation, TBA assay showed that the levels of MAD were 1.4 and 3.5 times in 20 mW/cm2 group and 30 mW/cm2 group respectively compared with control group, there were significant differences among them (P < 0.05). NBT method shows that the activity of SOD were 68.2%, 46.2% and 36.0% of 10, 20 and 30 mW/cm2 groups respectively compared with control group, there were significant differences among them too (P < 0.01). CONCLUSION: Microwave Radiation could up-regulate the levels of MAD) while down-regulate the SOD activity.

Effect of alpha-tocopherol on pro-oxidant and antioxidant enzyme status in radiation-treated oral squamous cell carcinoma.

OBJECTIVES: The relationships between alpha-tocopherol, pro-oxidant and antioxidant enzyme status, and radiation toxicity were studied in stage II, III, and IVA oral squamous cell carcinoma patients. The low levels of malondialdehyde and increased activities of antioxidant enzymes were correlated with decreased oxidative stress by alpha-tocopherol in oral cancer patients treated with radiotherapy. The objective of the present study was to evaluate the effect of alpha-tocopherol on oxidant-antioxidant enzyme status in oral squamous cell carcinoma patients treated with radiotherapy. MATERIALS AND METHODS: The study included three groups with histologically confirmed oral squamous cell carcinoma patients (untreated), and they were further divided into two groups, viz., one consisting of patients who underwent radiotherapy alone (radiotherapy was given at the dosage of 6000 cGy in five fractions per week for a period of 6 weeks); and the other group treated with radiotherapy plus alpha-tocopherol supplementation (alpha-tocopherol was supplemented at a dosage of 400 IU/day) for the entire period of radiotherapy. RESULTS: A significant decrease ( P < 0.001) in malondialdehyde levels and increase in activities of antioxidant enzymes ( P < 0.001) in hemolysate were noticed in patients treated with radiotherapy and simultaneously supplemented with alpha-tocopherol when compared to radiation-treated patients. CONCLUSION: It was seen that alpha-tocopherol played a role in protecting against the damage caused by irradiation in oral squamous cell carcinoma patients treated with radiotherapy, by enhancing the antioxidant enzyme status and reducing the pro-oxidant status.

Formulation of ELF magnetic fields' effects on malondialdehyde level and myeloperoxidase activity in kidney using genetic programming.

In vivo exposure effects of electromagnetic fields (EMFs) on various tissues of experiment animals have been investigated. In this sense, modeling and formulation of these biological effects have been of significant importance. In this study extremely low frequency (ELF) EMFs effects on malondialdehyde (MDA) level and myeloperoxidase (MPO) activity in kidney of guinea pigs exposed to 50 Hz magnetic fields of 1 mT, 2 mT and 3 mT have been presented. It has been planned to determine whether genetic programming (GP) is appropriate to analyze and formulate these biological effects. Consequently, it has been observed that GP can be effectively used to model MDA level and MPO activity. The performances of prediction of the proposed GP formulation versus actual experimental values are found to be quite satisfactory in terms of standard deviation and correlation coefficient. It is concluded that the GP application serves to form a database for the researchers in this field, without exposing tissues to EMF and without using too many guinea pigs.

Plasma level of lipid peroxidation, total sulphydryl groups and nitric oxide levels in cancer patients irradiated on different anatomic fields: a case-control study.

AIM: The aim of this study was to evaluate the effect of radiotherapy on lipid peroxidation, total sulfhydryl groups (RSH) and nitric oxide (NO radical) levels in plasma of cancer patients treated on different anatomic sites, and to compare the results with control subjects. METHODS: 89 patients with various malignancies and 33 healthy control subjects were recruited for the study. Cancer patients were grouped according to the irradiation portals (head and neck, thoracic, breast, abdominal and pelvic). Two blood samples before and after the completion of the fifth week of radiotherapy were collected from each patient. RESULTS: Plasma levels of malondialdehyde (MDA) and NO radical of cancer patients before irradiation were found higher than those in control subjects. After irradiation, a marked lipid peroxidation increase was demonstrated as well as the significant decrease of plasma RSH level. CONCLUSION: The alterations of the parameters indicate enhanced oxidant stress and point to the necessity of antioxidant prophylaxis upon application of radiotherapy.

Melatonin protects against ionizing radiation-induced oxidative damage in corpus cavernosum and urinary bladder in rats.

The objective of this study was to examine the potential radioprotective properties of pharmacological doses of melatonin on corpus cavernosum and bladder tissues of whole-body irradiated (IR) rats. A total of 32 male Sprague-Dawley rats were exposed to irradiation performed with a LINAC which produced 6 MV photons at a focus 100 cm distant from the skin. Under ketamine anesthesia, each rat received a single whole-body dose of 800 cGy. Immediately before and after IR, rats were treated with either saline or melatonin (20 and 10 mg/kg, i.p.) and decapitated at 12 hr after exposure to irradiation. Another group of rats was followed for 72 hr after IR, where melatonin injections were repeated once daily. Tissue levels of malondialdehyde (MDA), an index of lipid peroxidation, and glutathione (GSH), a key antioxidant, were estimated in corpus cavernosum and urinary bladder. Tissues were also examined microscopically. The results demonstrate that both 12 and 72 hr following IR, tissue levels of MDA were elevated (P < 0.001), while GSH levels were reduced (P < 0.01) in both tissues. On the other hand, melatonin reversed these changes significantly (P < 0.05-0.01), concomitant with the improvement in histological appearances. Our results show that whole-body irradiation causes oxidative damage in the tissues of the genitourinary system. As melatonin administration reversed oxidative organ injury, as assessed by biochemical and histopathological findings, it is suggested that supplementing cancer patients with adjuvant therapy of melatonin may have some benefit for successful radiotherapy.

Effect of 1.7 MHz ultrasound on a gas-vacuolate cyanobacterium and a gas-vacuole negative cyanobacterium.

Ultrasonic signals propagated through medium were directly applied to unicellular cyanobacterium cell surfaces to investigate the biological effects induced by ultrasound. The gas-vacuolate cyanobacterium Microcystis aeruginosa and the gas-vacuole negative cyanobacterium Synechococcus PCC 7942 responded differently to ultrasound. When M. aeruginosa was irradiated by 1.7 MHz ultrasound at 0.6 W cm(-2) every day, it showed a decrease of nearly 65% in biomass increment, and this group's generation time increased twice as much as the control. While Synechococcus culture irradiated every day still grew as fast as the control, and its final biomass was as much as the control. The value of the electric conductivity change (Deltasigma) sharply increased in Microcystis suspension during the exposure process, which revealed more ultrasonic cavitation yield in liquid related to the gas-vacuolate cyanobacteria. The relative malondialdehyde (MDA) content, a quantitative indicator of lipid peroxidation, increased by 65% in Microcystis cells and 9% in Synechoccus cells after ultrasonic irradiation. Moreover, the membrane permeability, quantified by measuring the relative amount of electrolyte leaking out of cells, increased to more than 60% in the Microcystis cells. The results indicated that Microcystis cells were susceptible to ultrasonic stress. According to Rayleigh-Plesset's bubble activation theory, 1.7 MHz ultrasound approached the eigenfrequency of gas-vacuolate cells. The present investigation suggested the importance of the cavitational effect relative to intracellular gas-vacuoles in the loss of cell viability. In summary, 1.7 MHz ultrasonic irradiation was effective in preventing water-bloom forming cyanobacteria from growing rapidly due to changes in the functioning and integrity of cellular and subcellular structures.

Melatonin reduces lipid peroxidation and nitric oxide during irradiation-induced oxidative injury in the rat liver.

Radiation therapy is a popular and useful tool in the treatment of cancer. Melatonin participates in the regulation of a number of important physiological and pathological processes. Melatonin, a powerful endogenous antioxidant, plays a role in the reduction of oxidative damage. Thirty adult rats were divided into five equal groups. On the day of the experiment, groups I and II were injected with 5 or 10 mg/kg melatonin, respectively, while group III received isotonic NaCl solution. Thirty minutes later, groups I, II and III were exposed to 6.0 Gy whole body ionizing radiation in a single fraction. Group IV was injected with 5 mg/kg melatonin but was not irradiated. The final group was reserved as sham treated. Liver malondialdehyde (MDA) and nitric oxide (NO*) levels were measured in all groups. Whole body irradiation caused a significant increase in liver MDA and NO* levels. Hepatic MDA and NO* levels in irradiated rats that were pretreated with melatonin (5 or 10 mg/kg) were significantly decreased. Malondialdehyde and NO* levels were reduced in a dose-related manner by melatonin. The data show that melatonin reduces liver damage inflicted by irradiation when given prior to the exposure to ionizing radiation. The radioprotective effect of melatonin is likely achieved by its ability to function as a scavenger for free radicals generated by ionizing radiation.

[Influence of small doses of fractionated X-ray radiation on the activity of histone-specific proteases and the content of malonic dialdehyde in chromatin of the cells of rat liver]. / Vliianie fraktsionirovannogo rentgenovskogo oblucheniia v malykh dozakh na aktivnost' gistonospetsificheskikh proteinaz i soderzhanie malonovogo dial'degida v khromatine kletok pecheni krys.

The fractionated X-ray irradiation resulted in accumulation of malonic dialdehyde (MDA) in chromatin of the cells of rat liver and activation of nuclear endogenous histon-specific proteases. Seven days after the termination of irradiation, the activity of the nuclear proteases returned to the control level and the MDA level remained 10% above the control parameter. The correlation (r = 0.71) of the processes of MDA accumulation in chromatin and activation of histon-specific proteases in the cells of rat liver after the termination of irradiation showed that these processes were coupled. Transplantation of Guerin's carcinoma to the irradiated animals caused the changes in nuclear proteolysis of the histones and MDA level in chromatin of the tumor-carrier liver cells, which lessened the influence of preliminary X-ray irradiation on rats.