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.

Effect of high pressure and thermal processing on spoilage-causing enzymes in mango (Mangifera indica).

The aim of the present work was to model the effect of combined pressure-temperature processing on spoilage-causing enzymes in mango pulp; which conventionally are inactivated using high temperatures leading to inevitable quality losses. The inactivation of enzymes pectin methylesterase (PME), polyphenol oxidase (PPO) and peroxidase (POD) was studied in mango pulp within the pressure, temperature and hold-time ranges of 0.1 to 600MPa, 40 to 70°C and 1s to 90min, respectively. The enzyme inactivation was described as a dual process: initial change in activity during dynamic pressure build-up phase and subsequent decrease under isobaric-isothermal conditions. The former led to considerable increase in activities of all the three enzymes (p<0.05); however, the increased activity reduced with increased intensity of applied pressure-temperature. On the other hand, isobaric-isothermal conditions led to substantial inactivation (p<0.05), with 600MPa/70°C/20min treatment being most effective in reducing the activities of PME, PPO and POD to 32, 15 and 26%, respectively. The enzyme inactivation data was non-linear under isobaric-isothermal conditions and fitted to the nth-order reaction model, indicative of the occurrence of series of reactions possibly due to pressure-temperature interaction effects. The estimated reaction order 'n' was 0.815, 1.106 and 1.137 for PME, PPO and POD, respectively. The estimated reaction rate constant k (min-1) depicted PME to be the most baroresistant enzyme followed by POD and PPO. Temperature and pressure dependency of k was expressed in terms of activation energy and activation volume using the Arrhenius- and Eyring-type relations, respectively. An empirical model with good correlation between actual and predicted data (R2>0.90) was proposed to simulate the rate of enzyme inactivation under isobaric-isothermal conditions as a function of pressure and temperature.

Differential modulation of inflammatory markers in plasma and skin after single exposures to UVA or UVB radiation in vivo.

BACKGROUND: Solar light generates inflammatory responses in exposed skin. These effects are generally attributed to UVB light. However, skin is expose d to a huge quantum of UVA photons as UVA is a predominant part of sunlight and the radiation used in tanning beds. We examined the effects of a single exposure to UVA and UVB wavebands on cytokine levels in skin and plasma, myeloperoxidase (MPO) activity, expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) in skin. METHODS: Hairless mice were irradiated with either UVA (10 or 20 J/cm²) or UVB (200 or 800 mJ/cm²). The effects were assessed after 4/24 h. Plasma cytokine levels were evaluated using a Bio-Plex cytokine assay. Cytokine, iNOS and COX-2 levels in skin were determined by Western blot. Skin MPO activity was monitored spectrophotometrically. RESULTS: UVB induced up-regulation of interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) and decrease in interleukin-10 (IL-10) mainly after 4 h. In contrast, UVA caused increase in levels of tumor necrosis factor-alpha (TNF-α) and IL-6 after 4 h and up-regulated IL-10 and interleukin-12 (IL-12) after 24 h. The increase in MPO activity from infiltrated leucocytes was observed only in UVB irradiated animals. iNOS was up-regulated 4 h after UVA and UVB treatment. No significant effect on COX-2 expression was detected. CONCLUSIONS: UVA and UVB light affected several inflammatory markers. For individual waveband, changes in plasma parameters did not correlate with those in skin. Thus evaluation of plasma samples cannot simply be replaced by determination in skin specimens and vice versa.

New insights into the molecular pathology of radiation-induced pneumopathy.

BACKGROUND AND PURPOSE: Pneumonitis and fibrosis constitute dose-limiting side effects of thorax or total body irradiation. An improved understanding of the underlying mechanisms is a prerequisite for the development of effective radioprotective strategies. Here we characterized the behavior of resident and immune cells in a murine model of radiation-induced pneumopathy. MATERIALS AND METHODS: Wild type (WT) or RAG-2 deficient C57BL/6 mice received 15 Gray of (hemi)-thorax irradiation in a single dose. Bronchoalveolar lavage fluid (BALF) and lung tissue were collected at defined time points post-irradiation for the determination of apoptosis, microvascular injury, and histological and immunohistochemical analyses. RESULTS: Higher albumin levels and increased apoptosis were detected in the BALF 21 days after irradiation, indicative for delayed damage to resident cells. Irradiation also induced time-dependent changes in the BALF cytokine profile, the recruitment of activated T-cells into the lung and the formation of lipid-loaded resident cells. Lung fibrosis occurred earlier in RAG-2(-/-) mice, which lack mature T and B cells, compared to WT mice. CONCLUSIONS: Thorax irradiation triggers a delayed disturbance of tissue integrity and lipid metabolism in the lung. Activated T-lymphocytes infiltrating the lung tissue upon thorax irradiation participate in the protection of the lung from radiation-induced fibrosis.

Effect of defocused infrared diode laser on salivary flow rate and some salivary parameters of rats.

This study aims to investigate whether infrared diode low-level laser therapy (LLLT) increased salivary flow rate and altered pH value, protein concentration, and peroxidase and amylase activities in saliva of rats. Wistar rats were used and divided into three groups. Experimental groups (A and B) had their parotid, submandibular and sublingual glands submitted to diode laser, 808-nm wavelength, on two consecutive days. The dose results were 4 and 8 J/cm(2), respectively. A red guide light was used to visualize the irradiated area. Group C was irradiated only with red pilot beam and served as control. The saliva samples were collected after each irradiation step (first and second collection days) and 1 week after the first irradiation (seventh day). Statistical analysis was performed, and differences were observed according to different days of salivary collection. The results showed that salivary flow rate for groups A and B was higher on the seventh day if it is compared to data obtained for the first day (p < 0.05). LLLT applications on salivary glands are a therapy procedure that requires further studies.

Immunocytochemical characteristics of human osteosarcoma cell line HS-Os-1: possible implication in apoptotic resistance against irradiation.

In our previous study, we examined reactive oxygen species (ROS) formation in T lymphocytes following 5 Gy irradiation. We found that ROS formation occurred immediately after irradiation, continued for several hours, and resulted in oxidative DNA damage. Therefore, the origin of the hyper-radiosensitivity of T lymphocytes seemed to be the high production of ROS in the mitochondrial DNA following irradiation. In the succeeding study, we examined radiation-induced ROS formation, oxidative DNA damage, early apoptotic changes, and mitochondrial membrane dysfunction in the human osteosarcoma cell line HS-Os-1. We found that ROS formation and oxidative DNA damage were actually scarcely seen after irradiation of up to 30 Gy in these cells, that mitochondrial membrane potential was preserved, and that apoptotic changes were not demonstrated despite the relatively high-dose irradiation of 30 Gy. In the present study, we examined the immunocytochemical characteristics of the apoptotic-resistance of the HS-Os-1 cell line against irradiation in order to clarify its possible implications regarding radiosensitivity. The results showed that these cells lack P53 and Bax protein expression, and strong peroxidase activity was confirmed in the nuclei of the cells. Moreover, SODII (manganese superoxide dismutase II) protein expression was gradually increased in spite of irradiation of up to 30 Gy. Therefore, it is concluded that HS-Os-1 cells are originally apoptotic-resistant and that the cells possess a strong ability to scavenge for free radicals. To convert these cells to a state of apoptotic-susceptibility, a powerful oxidant such as hydrogen peroxide might exert such an effect in terms of the production of hydroxyl radicals in lysosomes in the cells as shown in our previous studies. The origin of the radioresistance of the human osteosarcoma cell line HS-Os-1 is considered to to be low degree of ROS formation following irradiation, reflecting the strong scavenging ability of these cells for free radicals including hydroxyl radicals.

The synthetic somatostatin analogue, octreotide, ameliorates acute and delayed intestinal radiation injury.

PURPOSE: Reducing intraluminal proteolytic activity attenuates intestinal radiation toxicity. This study assessed whether pharmacological inhibition of exocrine pancreatic secretion protects against early and delayed radiation enteropathy in a preclinical rat model. METHODS AND MATERIALS: Rat ileum was sham-irradiated or exposed to 16 once-daily 4.2 Gy fractions of X-radiation. Vehicle or somatostatin analogue (octreotide, 2 microg/kg/hr) were administered from 2 days prior to 10 days after the end of irradiation. Mucosal injury was monitored noninvasively by assessment of granulocyte transmigration. Radiation injury was assessed at 2 weeks (early phase) and 26 weeks (chronic phase) using quantitative histopathology, immunohistochemistry, and morphometry. RESULTS: Octreotide decreased granulocyte transmigration (p<0.0006), reduced accumulation of myeloperoxidase-positive cells at 2 weeks (p = 0.0002), attenuated structural injury at 2 weeks (p = 0.04) and 26 weeks (p = 0.02), preserved mucosal surface area at 2 weeks (p = 0.0008) and 26 weeks p = 0.0008), and reduced intestinal wall thickening at 26 weeks (p = 0.002). Octreotide did not affect granulocyte transmigration, histology, or mucosal surface area in sham-irradiated controls. CONCLUSION: These results demonstrate the importance of consequential mechanisms in the pathogenesis of chronic radiation enteropathy. Short-term octreotide administration ameliorates acute radiation-induced mucosal injury, as well as chronic structural changes, and should be subject to further preclinical and clinical testing.

Exposure to ionizing radiation increases responsiveness to neural secretory stimuli in the ferret jejunum in vitro.

Experiments were designed to determine the effects of ionizing radiation on jejunal epithelial function in the ferret in vitro. Basal and stimulated electrolyte transport were determined in Ussing chambers at 0.5, 2, 24 and 48 h post-irradiation. Tissue histamine and 5-hydroxytryptamine levels were measured. Myeloperoxidase activity was also measured as an index of inflammation. Basal short circuit current was reduced at 2 h post-irradiation, but was elevated at 48 h. Basal conductance was significantly increased by 24 and 48 h. Responsiveness to electrical field stimulation was depressed at 0.5 h, and was greater than control by 24 and 48 h post-irradiation. Similarly, short circuit current responses to prostaglandin E2 were depressed at 0.5 h and elevated at 24 h. No significant change was observed in the response to carbachol post-irradiation, indicating that alterations in responsiveness were not likely at the level of the enterocyte. Changes in responsiveness to electrical field stimulation correlated significantly with increases in mucosal mast cell numbers. Myeloperoxidase activity, indicative of neutrophil infiltration, did not increase post-irradiation, nor was there histological evidence of an inflammatory cell infiltrate. There were no changes in tissue histamine or 5-hydroxytryptamine. Histology also revealed little microscopic morphological change from shams in tissue from irradiated ferrets. The results of this study demonstrate effects of irradiation on electrolyte transport in the ferret jejunum. The enhanced neurally evoked electrolyte transport observed at 24-48 h post-irradiation was not correlated with the development of inflammation, but was correlated with changes in mast cell numbers.

Development of primary hypothyroidism with antithyroglobulin, antiperoxidase, and blocking-type thyrotropin receptor antibodies after radiation therapy for neuroblastoma.

We describe a girl with hypothyroidism and blocking-type thyrotropin receptor antibodies that developed after chemotherapy and irradiation of the neck region for neuroblastoma. Results of thyroid studies before treatment were normal. Twenty months after completion of treatment, the girl had hypothyroidism with high titers of blocking-type thyrotropin receptor antibodies, antithyroglobulin, and antiperoxidase antibodies.

Peroxidase changes in barley induced by ionizing and thermal radiation.

Thermal and ionizing (gamma-ray) radiations were used to induce damage to barley seeds (IB65). The activity and isozyme banding patterns of peroxidase were compared. It was found that both physical agents caused damage to barley seeds (as observed from seedling height), but their action on peroxidase activity is not similar. Gamma-Rays enhance peroxidase activity. Thermal radiation, on the other hand, tends to reduce it but fails to alter the number of peroxidase isozymes. It is conjectured that the pathways of damage by thermal and ionizing radiations are not the same.

A critical analysis of the use of radiation inactivation to measure the mass of protein.

Measurements are presented of the radiation inactivation of four enzymes exposed to a 6 MeV proton beam. It has long been thought that the measurement of the susceptibility of an enzyme to ionizing radiation can be used to determine its molecular mass. Results are frequently interpreted using the empirical analysis of Kempner and Macey (Biochim. Biophys. Acta 163, 188-203, 1963). We examine this analysis and discuss the validity and limitations of the assumptions on which it is based. Our results indicate that the specific biochemical properties of each enzyme make a significant contribution to its radiation sensitivity.

[The significance of the hypoxic factor in adaptation to the action of ionizing radiation as a result of the accident at the Chernobyl Atomic Electric Power Station]. / Pro znachennia hipoksychnoho faktora v adaptatsiï do diï ionizuiuchoho vyprominiuvannia vnaslidok avariï na ChAES.

Data are presented from cytochemical study of the neutrophil myeloperoxidase oxygen dependent enzymes and lymphocyte succinate dehydrogenase in the peripheral blood of 2169 persons subjected to follow-ups of many kinds, at year 7 and 8 after the Chernobyl accident. By comparison with early time periods, the process of normalization of the measured values has been found to be the case, with SDG returning to normal earlier than MPO. There was an increase in the number of individuals with reduced MPO activity and stable percentage of those demonstrating increased SDG activity (30-42% versus 12%). Significance of the adaptation process in the time course of changes of the values measured is discussed along with role of hypoxic factor in adaptation to the ionizing irradiation exposure after the Chernobyl accident.

Target size analysis of prostaglandin endoperoxide synthase. Radiation inactivation of both cyclooxygenase and peroxidase correlated with the monomer of 72 kDa.

To determine the size of the functional catalytic unit of prostaglandin endoperoxide (prostaglandin H) synthase, radiation inactivation experiments were performed. Both microsomes from ovine seminal vesicles and purified enzyme were irradiated with 10 MeV electrons. The enzymic activities of prostaglandin H synthase, cyclooxygenase and peroxidase, showed mono-exponential inactivation curves dependent on radiation dose, indicating molecular masses of approximately 72 kDa. The enzyme in microsomes, in its native environment, as well as in its purified state after solubilisation with nonionic detergent showed identical molecular masses. The results clearly demonstrate that the monomer of the enzyme with an apparent molecular mass of 72 kDa (SDS/PAGE) is the functional unit for catalysis of both activities. Hence the two active sites of cyclooxygenase and peroxidase reside on the same polypeptide chain.

[Effect of UV radiation and the autotransfusion of UV-irradiated blood on the content of cationic proteins in the neutrophilic granulocytes of calves]. / Vliianie UF izlucheniia i autotransfuzii UF-obluchennoi krovi na soderzhanie kationnykh belkov v neitrofil'nykh granulotsitakh teliat.

A study was made of the influence of UV-irradiation (254 nm) of blood in vitro, of the autotransfusion of UV-irradiated blood (AUVIB), and of the mixture of UV-irradiated and intact blood in vitro on the content of bactericidal cation proteins (CP) in blood neutrophil of calves suffered from dyspepsia and broncho-pneumonia. Age differences were noticed in CP contents and their decrease in neutrophils following AUVIB in vivo and administration of the mixture of blood in vitro. The decrease in cell CP contents is presumably due to neutrophil degranulation and CP release into the blood plasma. Since the initial mechanisms of neutrophil degranulation are located on the cell surface, the CP release is supposed to result from a membranotropic effect of UV-irradiated blood on the intact autologous blood. This effect may explain the increase in nonspecific resistance of organism after the AUVIB, being one of the main therapeutic phenomena of the AUVIB-therapy.