Assessment of monoamine neurotransmitters in the cortex and cerebellum of gamma-irradiated mice: A neuromodulatory role of Cynodon dactylon.

INTRODUCTION: Radiation is an important tool in the diagnostic and curative treatment of many cancers. Ionizing radiation induces many biochemical changes in the cells. The present study was designed to estimate the level of neurotransmitters in the distinct brain tissue of Swiss albino mice before exposing gamma radiation. MATERIALS AND METHODS: The mice were treated with 0.25 and 1 g/kg body weight of Cynodon dactylon extract (CDE) via oral gavage for 7 days and subjected to 5 Gy of gamma radiation. The estimation of monoamines was performed in the cortex and cerebellum separately. RESULTS: Mice exposed to a sublethal dose 5 Gy of gamma radiation causes a significant decrease in dopamine, norepinephrine, epinephrine, and serotonin levels compared to normal. The mice treated with 0.25 and 1 g/kg body weight of CDE via oral gavage for 7 days showed significant improvement in the level of monoamine neurotransmitters in both the cortex and cerebellum homogenate. CONCLUSION: Oral administration of antioxidant-rich C. dactylon has shown a neuromodulatory effect against radiation-induced depletion of neurotransmitters in the brain tissues.

An osteoinductive effect of phytol on mouse mesenchymal stem cells (C3H10T1/2) towards osteoblasts.

In recent years, phytochemicals have been widely researched and utilized for the treatment of various medical conditions such as cancer, cardiovascular diseases, age-related problems and are also said to have bone regenerative effects. In this study, phytol (3,7,11,15-tetramethylhexadec-2-en-1-ol), an acyclic unsaturated diterpene alcohol and a secondary metabolite derived from aromatic plants was investigated for its effect on osteogenesis. Phytol was found to be nontoxic in mouse mesenchymal stem cells (C3H10T1/2). At the cellular level, phytol-treatment promoted osteoblast differentiation, as seen by the increased calcium deposits. At the molecular level, phytol-treatment stimulated the expression of Runx2 (a bone-related transcription factor) and other osteogenic marker genes. MicroRNAs (miRNAs) play an essential role in controlling bone metabolism by targeting genes at the post-transcriptional level. Upon phytol-treatment in C3H10T1/2 cells, mir-21a and Smad7 levels were increased and decreased, respectively. It was previously reported that mir-21a targets Smad7 (an antagonist of TGF-beta1 signaling) and thus, protects Runx2 from its degradation. Thus, based on our results, we suggest that phytol-treatment promoted osteoblast differentiation in C3H10T1/2 cells via Runx2 due to downregulation of Smad7 by mir-21a. Henceforth, phytol was identified to bolster osteoblast differentiation, which in turn may be used for bone regeneration.

Defect engineering, microstructural examination and improvement of ultrafast third harmonic generation in GaZnO nanostructures: a study of e-beam irradiation.

Electron beam induced effects on defect engineering and structural, morphological and optical properties of Ga doped ZnO (GaZnO) nanostructures for improved ultrafast nonlinear optical properties are presented. A microstructural analysis was carried out based on the Scherrer, Williamson-Hall, and size-strain models. All three models reveal a peak broadening effect upon electron beam irradiation (EBI) and the crystallite size of the films shows a decrease of 30% compared to unirradiated nanostructures. The decrease in intensity, variation in the peak position and broadening of the Raman E2H mode confirm that the EBI treatment introduces disorder into the nanostructures. The interband gap emissions observed in photoluminescence spectra are primarily due to defect-related emissions originating from intrinsic defects such as Zni, Oi, VZn, VO, VZn+, VO+ and OZn. The O1s core-level spectra show that the peak related to oxygen vacancy defects is suppressed upon EBI. Surface morphology studies reveal that the nucleation barriers of GaZnO nanostructures are reduced upon irradiation treatment resulting in a coalescence mechanism. Third harmonic generation studies show that higher electron-beam doses lead to the occurrence of enhanced THG signals due to a drastic change in the occupation of localized defect levels. Thermally induced nonlinear optical studies depict an improved χ(3) of 1.71 × 10-3 esu upon irradiation due to enhanced FCA induced TPA mechanism and non-radiative transitions which indicates the credibility of the grown films in photonic devices.

Dose rate effect on micronuclei induction in human blood lymphocytes exposed to single pulse and multiple pulses of electrons.

The effects of single pulses and multiple pulses of 7 MV electrons on micronuclei (MN) induction in cytokinesis-blocked human peripheral blood lymphocytes (PBLs) were investigated over a wide range of dose rates per pulse (instantaneous dose rate). PBLs were exposed to graded doses of 2, 3, 4, 6, and 8 Gy of single electron pulses of varying pulse widths at different dose rates per pulse, ranging from 1 × 10(6) Gy s(-1) to 3.2 × 10(8) Gy s(-1). Different dose rates per pulse were achieved by changing the dose per electron pulse by adjusting the beam current and pulse width. MN yields per unit absorbed dose after irradiation with single electron pulses were compared with those of multiple pulses of electrons. A significant decrease in the MN yield with increasing dose rates per pulse was observed, when dose was delivered by a single electron pulse. However, no reduction in the MN yield was observed when dose was delivered by multiple pulses of electrons. The decrease in the yield at high dose rates per pulse suggests possible radical recombination, which leads to decreased biological damage. Cellular response to the presence of very large numbers of chromosomal breaks may also alter the damage.

Regulation of Runx2 and Its Signaling Pathways by MicroRNAs in Breast Cancer Metastasis.

As a major threat among women globally, breast cancer (BC) emerges as a primary research focus for several researchers. Although various therapeutic regimens are available, there is an increased chance of metastasis of BC cells, which raises the severity of this malignancy. Of multiple preferred secondary targets, metastasis to bone is extensively studied. Besides deemed as a bone transcription factor, Runx2 also acts as a metastatic factor that promotes growth and metastasis of BC cells. Studies have reported the significant role of microRNAs (miRNAs) in BC pathogenesis and metastasis by governing Runx2 expression. Additionally, dysregulation of the signaling pathways, including Wnt/ß-catenin, TGF-ß, Notch, and PI3K/AKT, has been observed to influence the expression of Runx2 in BC cells. In this review, we have aimed to highlight the regulatory role of miRNAs in targeting Runx2 both directly and indirectly by governing respective signaling pathways during bone metastasis of BC.

Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO4 Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation.

The polymer electrolyte films (poly((vinylidene fluoride)-co-hexafluoropropylene)/LiClO4@90:10 w/w, PHL10) were prepared by solution-casting technique and the effect of various dosages of electron beam (EB) irradiation on structure, morphology, thermal, dielectric, and conductivity properties at various dosages. The atomic force microscope topography image shows substantial change in surface morphology due to irradiation and the modification of chemical bonds through chain scission process with increased EB dose was confirmed by Fourier transform infrared spectroscopy studies. NMR studies confirm the change in structural properties due to irradiation. The X-ray diffractometer confirms the decreased crystallinity from 50.10 for unirradiated film to 40.96 at 120 kGy doses; hence, increase in amorphousity due to a decrease in melting temperature from 460 to 418 °C leads to the degradation of the polymer, and the differential scanning calorimetry study reveals the decreased crystallinity with increased irradiation dose. The dielectric and modulus parameters are observed to decrease with increasing frequency as well as temperature. The conductivity increases with frequency and EB dose due to the increased segmental motion of charged ions by chain scission/cross-linking process. The high conductivity of 1.81 × 10-3 S/cm with the corresponding relaxation time of 1.697 × 10-6 at 120 kGy dose was observed. The conduction mechanism reveals an Ohmic behavior and the I-V plot exhibits a gradual increase in current with applied voltage as well as irradiation dose. The electrochemical performance of the irradiated polymer electrolyte was improved significantly and hence the polymer electrolytes can be used in solid-state batteries and storage applications after altering the properties by the influence of irradiation.

Inhibition of ERK1/2 or AKT Activity Equally Enhances Radiation Sensitization in B16F10 Cells.

BACKGROUND: The aim of the study was to evaluate the radiation sensitizing ability of ERK1/2, PI3K-AKT and JNK inhibitors in highly radiation resistant and metastatic B16F10 cells which carry wild-type Ras and Braf. METHODS: Mouse melanoma cell line B16F10 was exposed to 1.0, 2.0 and 3.0 Gy of electron beam radiation. Phosphorylated ERK1/2, AKT and JNK levels were estimated by ELISA. Cells were exposed to 2.0 and 3.0 Gy of radiation with or without prior pharmacological inhibition of ERK1/2, AKT as well as JNK pathways. Cell death induced by radiation as well as upon inhibition of these pathways was measured by TUNEL assay using flow cytometry. RESULTS: Exposure of B16F10 cells to 1.0, 2.0 and 3.0 Gy of electron beam irradiation triggered an increase in all the three phosphorylated proteins compared to sham-treated and control groups. B16F10 cells pre-treated with either ERK1/2 or AKT inhibitors equally enhanced radiation-induced cell death at 2.0 as well as 3.0 Gy (P < 0.001), while inhibition of JNK pathway increased radiation-induced cell death to a lesser extent. Interestingly combined inhibition of ERK1/2 or AKT pathways did not show additional cell death compared to individual ERK1/2 or AKT inhibition. This indicates that ERK1/2 or AKT mediates radiation resistance through common downstream molecules in B16F10 cells. CONCLUSIONS: Even without activating mutations in Ras or Braf genes, ERK1/2 and AKT play a critical role in B16F10 cell survival upon radiation exposure and possibly act through common downstream effector/s.

Anticlastogenic, radiation antagonistic, and anti-inflammatory activities of Persea americana in albino Wistar rat model.

The present study was undertaken to evaluate the anti-inflammatory activity and antigenotoxic effect of hydroalcoholic leaf extract of Persea americana (P. americana) in albino Wistar rats against whole body X-ray irradiation. Rats were orally administered with (25, 50, 100, 200, and 400 mg/kg body weight) of P. americana leaf extract for five days. On the fifth day after last administration, animals were exposed to whole body X-rays of 8 Gy. Based on Kaplan Meier's survival analysis, 100 mg/kg body weight was selected as an optimum dose for radioprotection. The radioprotective potential was analysed by bone marrow micronucleus test and comet assay in peripheral blood lymphocytes. Biochemical estimations were performed in liver tissue homogenates. DNA damage indicators analysed through comet assay displayed significant reduction in olive tail movement (P < 0.01), percentage DNA in tail (P < 0.05) and tail length (P < 0.001) in pretreated group when compared to radiation group. P. americana leaf extract restored the levels of reduced glutathione, catalase, and reduced the levels of lipid peroxidation, protein carbonyls, and cyclooxygenase-2 levels in liver homogenates of pre-treated group. Decrease in micronucleated polychromatic erythrocytes (P < 0.05) was witnessed in P. americana pretreated group when compared to radiation control. Pretreatment also resulted in the increase of animal survival with dose reduction factor of 1.28. Our findings for the first time demonstrated that P. americana offers significant protection to rats from whole body exposure to X-rays and helps in antagonising the radiation effects, thereby combating acute radiation induced damage in living systems.

DOSE-RESPONSE STUDY USING MICRONUCLEUS CYTOME ASSAY: A TOOL FOR BIODOSIMETRY APPLICATION.

The present study is aimed at obtaining in vitro dose-response data for the induction of micronucleus (MN) and nucleoplasmic bridges (NPBs) in human lymphocytes using 60Co-gamma rays and 8 MeV pulsed electron beam. An attempt was made to validate the possibility of applying NPBs as new biodosimetry endpoint in the dose range of 0-6 Gy. A total of 1000 binucleated cells (BNCs) per dose point were evaluated for the frequency of MN and NPBs. From the study, it is clear that the dose-response increase of MN and NPBs is linear quadratic in nature. The study provides linear and quadratic parameter for biodosimetry application. The relative biological effectiveness value of the 8 MeV electron beam was estimated using slope values and is found to be 1.18 ± 0.01 for MN/BNCs, 1.27 ± 0.02 for the fraction of BNCs with MN, 1.16 ± 0.13 for MN/(BNCs with MN) and 1.09±0.01 for NPBs.

Evaluation of the Potency of Kinetin on Radiation Induced Behavioural Changes in Swiss Albino Mice.

INTRODUCTION: According to the various independent studies conducted, it is well evident fact that radiation induces oxidative stress in the living system. It is also proved that this oxidative stress will lead to the various behavioural changes such as anxiety and memory impairment. Kinetin is one of the important plant cytokine with anti-aging properties. However, very few studies were conducted to check its potential in ameliorating the behavioural changes induced by the ionizing radiation. AIM: This study was aimed to check the potential of kinetin in ameliorating the radiation induced behavioural changes in albino mice. MATERIALS AND METHODS: In this study, survival analysis was performed using three different dose of kinetin intervention along with, one radiation control group and one normal control group (n=50). Based on the cumulative survival rate, single effective dose of kinetin was selected and used to evaluate the behavioural changes induced by radiation. The open field apparatus was used to evaluate the anxiety level (n=18, six in each group). Eight armed radial maze was used to evaluate the memory and learning ability in mice model. RESULTS: Survival study results suggest 100 mg/kg body weight of kinetin showed highest cumulative survival rate. Therefore, this dose was selected as an effective drug dose for further study. Analysis also showed 6 Gy whole body electron beam radiation had significantly increased anxiety level, increased duration to complete the task as well as mistakes done during the task. Further, kinetin intervention had significantly ameliorated the same. CONCLUSION: A 100 mg/kg body weight of kinetin intervention helps in reducing the anxiety and improves the learning ability in mice exposed to electron beam radiation.

NATURAL RADIONUCLIDE LEVELS IN SEDIMENTS OF CAUVERY RIVERINE ENVIRONMENT.

The paper presents the systematic measurement of activity concentrations of 40K, 226Ra and 232Th in sediment sample of Cauvery river of Karnataka, South India. Activity was measured using HpGe gamma ray spectrometer, and the mean values of 40K, 226Ra and 232Th in the sediment samples were found to be 144.31, 32.05 and 61.70 Bq kg-1, respectively. To assess the radiological hazards in the samples, radium equivalent (Raeq), absorbed dose (D), annual effective equivalent dose (AEED), activity utilisation index (AUI) and annual gonadal dose equivalent (AGDE) values associated with the radionuclides were calculated and compared with international recommended values.

Functional Genomic Investigation of the Molecular Biological Impact of Electron Beam Radiation in Lymphoma Cells.

PURPOSE: The biological response of electron beam radiation (EBR) in tumors remains underexplored. This study describes the molecular biological and genomic impact of EBR on tumor cells. METHODS: A mouse model bearing Dalton's lymphoma ascites cells was exposed to an 8-MeV pulsed electron beam, at a dose rate of 2 Gy/min using a microtron, a linear accelerator. The radiation-induced changes were assessed by histopathology, fluorescence-activated cell sorting, signaling pathway-focused reporter assays, and gene expression by microarray analysis. RESULTS: EBR was found to increase apoptosis and G2-M cell cycle arrest with concomitant tumor regression in vivo. The microarray data revealed that EBR induced tumor regression, apoptosis, and cell cycle arrest mediated by p53, PPAR, and SMAD2/3/4 signaling pathways. Activation of interferon regulatory factor and NFkB signaling were also found upon EBR. Chemo-genomics exploration revealed the possibility of drugs that can be effectively used in combination with EBR. CONCLUSION: For the first time, an 8-MeV pulse EBR induced genomic changes, and their consequence in molecular and biological processes were identified in lymphoma cells. The comprehensive investigation of radiation-mediated responses in cancer cells also revealed the potential therapeutic features of EBR.

Haematopoietic, Antioxidant and Membrane Stabilizing Property of Diallyl Disulphide in Irradiated Mice.

INTRODUCTION: Diallyl disulphide is an organo-sulphur compound which is present in garlic and responsible for the characteristic odor of garlic. It is known for its anticancer and invitro membrane stabilizing properties. AIM: The main aim was to evaluate the haematopoietic, antioxidant and membrane stabilizing property of diallyl disulfide in irradiated mice. MATERIALS AND METHODS: Mice were grouped into 6 groups as control, drug control, radiation control and drug pre-treatment groups (i.e. drug administration + radiation group) The mice were fed orally for 15 consecutive days and on the 15(th) day, one hour after drug administration, the mice were irradiated with 6Gy electron beam radiation. The changes in blood cell count, total antioxidant levels, malondialdehyde and reduced glutathione levels were determined. The immunomodulatory response of DADS to the radiological effects was determined by the estimation of IL-6 levels. RESULTS: A significant improvement in pre-drug treatment group when compared to control groups in the haemoglobin, red blood cell count, white blood cell count, haematocrit and platelet counts was observed. There is an increased level of interleukin-6 in the drug treated groups compared to the radiation control. An increase in the malondialdehyde levels and decrease in the glutathione levels in the irradiated group indicate increased lipid peroxidation and oxidative stress, whereas, there is a significant reduction in the malondialdehyde levels and increased glutathione levels in the drug pre-treatment groups showing membrane stabilization. CONCLUSION: Thus DADS proves to be an effective haematopoietic and antioxidative agent to counter radiation induced haematopoietic suppression and oxidative stress.

Effect of electron-beam irradiation on antimicrobial, antibiofilm activity, and cytotoxicity of mouth rinses.

BACKGROUND: Oral health diseases are common in all regions of the world. Mouth rinses are widely used generally by population as a port of daily oral care regimen. In addition to antimicrobial activity, mouth rinses possess certain cytotoxic effects. Electron-beam (E-beam) radiation is a form of ionizing energy known to induce structural, physical, and chemical changes in irradiated products. In this study, the modulatory effects of E-beam in irradiated mouth rinses were evaluated for its biological activities. MATERIALS AND METHODS: The antimicrobial activities of nonirradiated and irradiated mouth rinses were evaluated for its antimicrobial and antibiofilm activities against oral pathogens, Enterococcus faecalis, Streptococcus mutans, Staphylococcus aureus, and Candida albicans. The antimicrobial activity was evaluated by disc diffusion method and antibiofilm activity was evaluated by O'Toole method. The cytotoxicity was evaluated against human gingival fibroblast (HGF) cells by 3-(4, 5 Dimethythiazol-yl)-2,5-Diphenyl-tetrazolium bromide assay. RESULTS: Colgate Plax (CP) exhibited the antimicrobial activity against the tested pathogens, and a significant (P< 0.05) increase was observed against S. aureus at 750 Gy irradiation. Further, CP significantly (P< 0.05) suppressed S. mutans, S. aureus, and C. albicans biofilm. Listerine (LS) inhibited S. mutans and C. albicans biofilm. Whereas irradiated CP and LS significantly (P< 0.05) suppressed the biofilm formed by oral pathogens. The suppression of biofilm by irradiated mouth rinses was dose- and species-dependent. There was no significant (P > 0.05) difference in the cytotoxicity of irradiated and nonirradiated mouth rinses on HGF cells. However, an increased percentage viability of HGF cells was observed by mouth rinses irradiated at 750 Gy.xs CONCLUSION: The E-beam irradiation enhanced the antibiofilm activity of mouth rinses without modifying the cytotoxicity.

Changes in spectrochemical and catalytic properties of biopolymer anchored Cu(II) and Ni(II) catalysts by electron beam irradiation.

Chitosan (a biopolymer) anchored Cu(II) and Ni(II) Schiff base complexes, [M(OIAC)Cl2] (M: Cu/Ni and OIAC: ([2-oxo-1H-indol-3-ylidene]amino)chitosan) were electron beam irradiated by different doses (100 Gy, 1 kGy and 10 kGy). The electron beam has shown potential impact on biopolymer's support, in detail chain linking and chain scissoring, as evidenced by viscosity studies, FT-IR and X-ray diffraction spectroscopic techniques. Due to these structural changes, thermal properties of the complexes were found to be changed. The surface of these heterogeneous complexes was also effectually altered by electron beam. As a consequence, pores and holes were created as probed by SEM technique. The catalytic activity of both non-irradiated and irradiated complexes was investigated in the aerobic oxidation of cyclohexane using hydrogen peroxide oxidant. The catalytic ability of the complexes was enhanced significantly after irradiation as the result of surface changes. The reusability of the complexes was also greatly affected because of the structural variations in polymeric support. In terms of both better catalytic activity along with the reusability, 1 kGy is suggested as the best dose to attain adequate increase in catalytic activity and good reusability.

Influence of electron beam irradiation on spectral, thermal, morphological and catalytic properties of Co(II) complex immobilized on chitosan's Schiff base.

This study was carried out to investigate the effect of electron beam irradiation on the spectral and catalytic properties of chitosan supported (ONClCl) tetra coordinated Co(II) complex, [Co(OIAC)Cl2]. The complex was subjected to electron beam irradiation of 100 Gy, 1 kGy and 10 kGy doses. Chain scission of chitosan was observed on irradiation at 100 Gy and 10 kGy and chain linking at 1 kGy as evidenced by viscosity and FT-IR spectroscopic studies. This observation was also confirmed by thermo gravimetric and differential thermogravimetric (TG-DTG) analysis. It revealed that the thermal stability of the complex was increased at 1 kGy irradiation and decreased at 100 Gy and 10 kGy. In addition, the effect of electron beam irradiation on the surface morphology of the complex was studied by scanning electron microscopy. Catalytic abilities of both non-irradiated complex and irradiated complexes were determined and compared in the cyclohexane oxidation using hydrogen peroxide oxidant. The catalytic activity was found to increase after irradiation at all doses. Though the complex irradiated at 10 kGy showed highest conversion efficiency, irradiation at 1 kGy is suggested as the best dose due to the extensive reusability and adequate catalytic ability of the complex.

Antimicrobial activity and stability of electron beam irradiated dental irrigants.

BACKGROUND: The electron beam (e-beam) radiation is considered as an effective means of sterilization of healthcare products as well as to induce the structural changes in the pharmaceutical agents/drug molecules. In addition to structural changes of pharmaceutical it also induces the formation of low molecular weight compounds with altered microbiological, physicochemical and toxicological properties. Among the several known medicaments, sodium hypochlorite (NaOCl) and chlorhexidine digluconate (CHX) are used as irrigants in dentistry to kill the pathogenic microorganisms like Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans and Candida albicans inhabiting the oral cavity. OBJECTIVES: The aim of this study was to evaluate the antimicrobial activity and stability of e-beam irradiated dental irrigants, NaOCl and CHX. MATERIALS AND METHODS: Two dental irrigants NaOCl (1.25% and 2.5%) and CHX (1% and 2%) were exposed to various doses of e-beam radiation. The antimicrobial activities of e-beam irradiated irrigants were compared with the non-irradiated (control) irrigants against E. faecalis, S. aureus, S. mutans and C. albicans by disc diffusion method. Following the storage, physico-chemical properties of the irrigants were recorded and the cytotoxic effect was evaluated on human gingival fibroblast cells. RESULT: The irrigants, 1.25% NaOCl and 1% CHX showed significantly increased antimicrobial activity against both E. faecalis, (16+0.0) and S. aureus (25+0.0) after irradiation with 1 kGy e-beam. Whereas, 2.5% NaOCl and 2% CHX showed slightly increased antimicrobial activity only against S. aureus (28+0.0). The significant difference was noticed in the antimicrobial activity and cytotoxicity of irradiated and non-irradiated irrigants following the storage for 180 d at 4(0)C. CONCLUSION: The e-beam irradiation increased the antimicrobial activity of irrigants without altering the biocompatibility.

Photo-bio-synthesis of irregular shaped functionalized gold nanoparticles using edible mushroom Pleurotus florida and its anticancer evaluation.

A green chemistry approach to the synthesis of gold nanoparticles using edible mushroom Pleurotus florida (Oyster mushroom) by photo-irradiation method has been attempted. The mixture containing the aqueous gold ions and the mushroom extract was exposed to sunlight; this resulted in the formation of biofunctionalized gold nanoparticles. These nanoparticles were characterized using various techniques like UV-visible spectroscopy; X-ray diffraction studies, Energy dispersive X-ray analysis, Field emission scanning electron microscopy, Atomic force microscopy, Transmission electron microscopy and Fourier transform infrared spectrometry. The obtained biofunctionalized gold nanoparticles showed effective anti-cancer property against four different cancer cell lines A-549 (Human lung carcinoma), K-562 (Human chronic myelogenous leukemia bone marrow), HeLa (Human cervix) and MDA-MB (Human adenocarcinoma mammary gland) and no lethal effect is observed in Vero (African green monkey kidney normal cell) cell lines.

The efficacy of nardostachys jatamansi against the radiation induced haematological damage in rats.

INTRODUCTION: Radiation is increasingly being used for medical purposes and it is an established weapon in the diagnosis and the therapy of cancer. An exposure to 1-2 Gys causes the NVD (Nausea, vomiting, diarrhoea) syndrome, whereas an exposure to 2-6 Gys causes the haematopoietic syndrome. The aim of the present study was to investigate the protective effect of the Nardostachys jatamansi root extract (NJE) on the radiation induced haematological damage in rats. MATERIALS AND METHODS: EBR was performed at the Microtron Centre, Mangalore University, India. Rats were treated with NJE once daily for 15 days before and after the irradiation. After the irradiation, blood was collected for determining the peripheral blood counts (RBC and WBC), haemoglobin, the platelet count and the packed cell volume (PCV) at 6 hours, 12 hours, 24 hours, 48 hours and 5, 10 and 15 days post irradiation. The data was analyzed by one way ANOVA, followed by the Tukey's test for multiple comparisons. RESULT: NJE provided protection against the radiation induced haematological disorders. The rats treated with NJE exhibited a time dependent significant elevation in all the haematological parameters which were studied and its modulation upto the near normal level was recorded. CONCLUSION: From this study, we concluded that, NJE provides protection by modulating the radiation induced damage on the haematopoietic system.

Dose rate effect of pulsed electron beam on micronucleus frequency in human peripheral blood lymphocytes.

The micronucleus assay in human peripheral blood lymphocytes is a sensitive indicator of radiation damage and could serve as a biological dosimeter in evaluating suspected overexposure to ionising radiation. Micronucleus (MN) frequency as a measure of chromosomal damage has also extensively been employed to quantify the effects of radiation dose rate on biological systems. Here we studied the effects of 8 MeV pulsed electron beam emitted by Microtron electron accelerator on MN induction at dose rates between 35 Gy min-1 and 352.5 Gy min-1. These dose rates were achieved by varying the pulse repetition rate (PRR). Fricke dosimeter was employed to measure the absorbed dose at different PRR and to ensure uniform dose distribution of the electron beam. To study the dose rate effect, blood samples were irradiated to an absorbed dose of (4.7+/-0.2) Gy at different rates and cytogenetic damage was quantified using the micronucleus assay. The obtained MN frequency showed no dose rate dependence within the studied dose rate range. Our earlier dose effect study using 8 MeV electrons revealed that the response of MN was linear-quadratic. Therefore, in the event of an accident, dose estimation can be made using linear-quadratic dose response parameters, without adding dose rate as a correction factor.