Nelly Babayan - Academia.edu (original) (raw)

Papers by Nelly Babayan

Research paper thumbnail of Increased Yield of Residual γH2AX Foci in p53-Deficient Human Lung Carcinoma Cells Exposed to Subpicosecond Beams of Accelerated Electrons

Bulletin of Experimental Biology and Medicine

Research paper thumbnail of Raw Data of Generated Dose-Response Curves

Research paper thumbnail of Incidence and Risk Factors of Acute Leukemias in Armenia: A Population-Based Study

Asian Pacific Journal of Cancer Prevention

80% of all pediatric leukemias with a peak incidence in age group <15 years old and a second peak... more 80% of all pediatric leukemias with a peak incidence in age group <15 years old and a second peak after 50 years of age (

Research paper thumbnail of Improving VAE based molecular representations for compound property prediction

Journal of Cheminformatics

Collecting labeled data for many important tasks in chemoinformatics is time consuming and requir... more Collecting labeled data for many important tasks in chemoinformatics is time consuming and requires expensive experiments. In recent years, machine learning has been used to learn rich representations of molecules using large scale unlabeled molecular datasets and transfer the knowledge to solve the more challenging tasks with limited datasets. Variational autoencoders are one of the tools that have been proposed to perform the transfer for both chemical property prediction and molecular generation tasks. In this work we propose a simple method to improve chemical property prediction performance of machine learning models by incorporating additional information on correlated molecular descriptors in the representations learned by variational autoencoders. We verify the method on three property prediction tasks. We explore the impact of the number of incorporated descriptors, correlation between the descriptors and the target properties, sizes of the datasets etc. Finally, we show th...

Research paper thumbnail of Screening of phytochemicals, toxicities, and activities of three Dillenia species

Journal of Herbmed Pharmacology

Introduction: Plants containing β-sitosterol and oleamide are important for various diseases. So,... more Introduction: Plants containing β-sitosterol and oleamide are important for various diseases. So, Dillenia indica, D. obovata, and D. pentagyna were investigated for phytochemicals, cytotoxicity and genotoxicity levels on peripheral blood mononuclear cells (PBMCs) and Hela cells. The protective effect of D. pentagyna extract on a HepG2 cell line was also investigated. Methods: Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) were used for phytochemical analysis. 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction (MTT) and comet assays were performed for toxicity testing and protective effects against DNA oxidative damage. Results: The major components were oleamide and β-sitosterol at 38.464-58.247% and 5.585- 6.887% with concentration and quantity of β-sitosterol at 0.2-0.37 mg/mL and 0.42-0.964 mg/g leaf. The D. indica, D. obovata, and D. pentagyna toxicities on PBMCs showed IC50 values at >430, &gt...

Research paper thumbnail of BARTSmiles: Generative Masked Language Models for Molecular Representations

Cornell University - arXiv, Nov 29, 2022

We discover a robust self-supervised strategy tailored towards molecular representations for gene... more We discover a robust self-supervised strategy tailored towards molecular representations for generative masked language models through a series of tailored, in-depth ablations. Using this pre-training strategy, we train BARTSmiles, a BART-like model with an order of magnitude more compute than previous self-supervised molecular representations. In-depth evaluations show that BARTSmiles consistently outperforms other self-supervised representations across classification, regression, and generation tasks setting a new state-of-the-art on 11 tasks. We then quantitatively show that when applied to the molecular domain, the BART objective learns representations that implicitly encode our downstream tasks of interest. For example, by selecting seven neurons from a frozen BARTSmiles, we can obtain a model having performance within two percentage points of the full fine-tuned model on task Clintox. Lastly, we show that standard attribution interpretability methods, when applied to BARTSmiles, highlight certain substructures that chemists use to explain specific properties of molecules. The code and the pretrained model are publicly available.

Research paper thumbnail of Colony-Forming Ability and Residual Foci of DNA Repair Proteins in Human Lung Fibroblasts Irradiated with Subpicosecond Beams of Accelerated Electrons

Bulletin of Experimental Biology and Medicine, 2021

We performed a comparative study of the colony-forming ability and the number of residual foci of... more We performed a comparative study of the colony-forming ability and the number of residual foci of DNA repair proteins in cultured human lung fibroblasts (MRC-5 cell line) after exposure to subpicosecond beams of accelerated electrons with an energy of 3.6 MeV and quasi-continuous radiation (accelerated electrons with an energy of 4 MeV and X-rays). The yield of damages causing reproductive cell death after pulsed subpicosecond radiation exposure was higher by ~1.8 times than after quasi-continuous radiation exposure. The quantitative yield of residual γH2AX foci (phosphorylated H2AX histone, a protein marker of DNA double breaks) in cells irradiated with subpicosecond beams of accelerated electrons was shown to be ~2.0- 2.5-fold higher than in cells irradiated with quasi-continuous beams of accelerated electrons.

Research paper thumbnail of Synthesis, characterization and toxicity studies of pyridinecarboxaldehydes and L-tryptophan derived Schiff bases and corresponding copper (II) complexes

F1000Research, 2016

Schiff bases and their metal-complexes are versatile compounds exhibiting a broad range of biolog... more Schiff bases and their metal-complexes are versatile compounds exhibiting a broad range of biological activities and thus actively used in the drug development process. The aim of the present study was the synthesis and characterization of new Schiff bases and their copper (II) complexes, derived from L-tryptophan and isomeric (2-; 3-; 4-) pyridinecarboxaldehydes, as well as the assessment of their toxicity in vitro. The optimal conditions of the Schiff base synthesis resulting in up to 75-85% yield of target products were identified. The structure-activity relationship analysis indicated that the location of the carboxaldehyde group at 2-, 3- or 4-position with regard to nitrogen of the pyridine ring in aldehyde component of the L-tryptophan derivative Schiff bases and corresponding copper complexes essentially change the biological activity of the compounds. The carboxaldehyde group at 2- and 4-positions leads to the higher cytotoxic activity, than that of at 3-position, and the p...

Research paper thumbnail of Influence of aflatoxin B1 on copy number variants in human leukocytes in vitro

Molecular Cytogenetics, Apr 9, 2015

Background: Aflatoxin B1 (AFB1) is a mycotoxin produced by Aspergillus spec. The latter are world... more Background: Aflatoxin B1 (AFB1) is a mycotoxin produced by Aspergillus spec. The latter are worldwide contaminants of food with mutagenic and carcinogenic activities in animals and humans. AFB1 was shown to have deleterious effects on metabolism of eukaryotes in many model systems, including the ability to inhibit DNA replication. An agent that disturbs DNA replication may also have the potential to induce de novo DNA copy number variations (CNVs). Results: Blood samples of three clinically healthy carriers were treated in vitro with AFB1 and chromosome preparations were subjected to parental origin determination fluorescence in situ hybridization (pod-FISH). Probes able to visualize CNVs in 8p21.2 and 15q11.2 were applied. In this setting here for the first time an influence of AFB1 on molecular-cytogenetically detectable CNVs could be shown. Conclusions: The obtained results indicate that: (i) pod-FISH is a single cell directed, sensitive and suitable method for the analysis of mutagen induced CNVs, (ii) AFB1 has the potential to induce in vitro instability of known CNVs in human leukocytes.

Research paper thumbnail of Gender differences in DNA damage/repair after laser-generated ultrafast electron beam irradiation

International Journal of Radiology & Radiation Therapy

The laser-driven particle acceleration technology has been developed over the last decade as a po... more The laser-driven particle acceleration technology has been developed over the last decade as a possible alternative to conventional particle accelerators. The significantly smaller size and cost, as well as the precise beam orientation compared with conventional cyclotrons ensure the potential application of laser-driven particle irradiation in imaging and treatment of cancerous cells. However, the radiobiological studies on laser-generated particle bunches are still required to promote its application in clinical practice. The aim of the work was to investigate the laser-generated ultrafast electron beam irradiation effect on DNA damage and repair in human peripheral blood mononuclear cells (PBMCs) with the respect to gender-specific radiosensitivity. The single cell gel-electrophoresis (comet) assay was used to analyze the level of DNA damage/repair. The level of DNA damages after irradiation was almost 3 times higher in female PBMCs, than that of in male PBMCs. The reparation capacity in female PBMCs was also lower, compared to male PBMCs. So, the difference between male and female DNA damage/repair response to laser-generated ultrafast electron beam irradiation was investigated. The gender bias in radiosensitivity was revealed, demonstrating higher female sensitivity to irradiation.

Research paper thumbnail of AREAL low energy electron beam applications in life and materials sciences

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2016

The AREAL laser-driven RF gun provides 2-5 MeV energy ultrashort electron pulses for experimental... more The AREAL laser-driven RF gun provides 2-5 MeV energy ultrashort electron pulses for experimental study in life and materials sciences. We report the first experimental results of the AREAL beam application in the study of molecular-genetic effects, silicon-dielectric structures, ferroelectric nanofilms, and single crystals for scintillators.

Research paper thumbnail of Radioprotective effect of creatine on DNA damage in peripheral blood mononuclear cells and adaptive properties of brain and liver creatine-creatine kinase system of the rats

"Radiation and Risk" Bulletin of the National Radiation and Epidemiological Registry

Research paper thumbnail of Low-Energy Laser-Driven Ultrashort Pulsed Electron Beam Irradiation-Induced Immune Response in Rats

International Journal of Molecular Sciences

The development of new laser-driven electron linear accelerators, providing unique ultrashort pul... more The development of new laser-driven electron linear accelerators, providing unique ultrashort pulsed electron beams (UPEBs) with low repetition rates, opens new opportunities for radiotherapy and new fronts for radiobiological research in general. Considering the growing interest in the application of UPEBs in radiation biology and medicine, the aim of this study was to reveal the changes in immune system in response to low-energy laser-driven UPEB whole-body irradiation in rodents. Forty male albino Wistar rats were exposed to laser-driven UPEB irradiation, after which different immunological parameters were studied on the 1st, 3rd, 7th, 14th, and 28th day after irradiation. According to the results, this type of irradiation induces alterations in the rat immune system, particularly by increasing the production of pro- and anti-inflammatory cytokines and elevating the DNA damage rate. Moreover, such an immune response reaches its maximal levels on the third day after laser-driven U...

Research paper thumbnail of The role of women scientists in the development of ultrashort pulsed laser technology-based biomedical research in Armenia

International Journal of Radiation Biology

Research paper thumbnail of Helix pomatia albumen gland water soluble protein extract as powerful antiaging agent

Research paper thumbnail of DNA double-strand break repair efficiency in cancer cells exposed to laser-driven ultrashort electron beams

Research paper thumbnail of Low Repair Capacity of DNA Double-Strand Breaks Induced by Laser-Driven Ultrashort Electron Beams in Cancer Cells

International Journal of Molecular Sciences

Laser-driven accelerators allow to generate ultrashort (from femto- to picoseconds) high peak dos... more Laser-driven accelerators allow to generate ultrashort (from femto- to picoseconds) high peak dose-rate (up to tens of GGy/s) accelerated particle beams. However, the radiobiological effects of ultrashort pulsed irradiation are still poorly studied. The aim of this work was to compare the formation and elimination of γH2AX and 53BP1 foci (well known markers for DNA double-strand breaks (DSBs)) in Hela cells exposed to ultrashort pulsed electron beams generated by Advanced Research Electron Accelerator Laboratory (AREAL) accelerator (electron energy 3.6 MeV, pulse duration 450 fs, pulse repetition rates 2 or 20 Hz) and quasi-continuous radiation generated by Varian accelerator (electron energy 4 MeV) at doses of 250–1000 mGy. Additionally, a study on the dose–response relationships of changes in the number of residual γH2AX foci in HeLa and A549 cells 24 h after irradiation at doses of 500–10,000 mGy were performed. We found no statistically significant differences in γH2AX and 53BP1...

Research paper thumbnail of Laser-Driven Ultrashort Pulsed Electron Beam Radiation at Doses of 0.5 and 1.0 Gy Induces Apoptosis in Human Fibroblasts

International Journal of Molecular Sciences

Rapidly evolving laser technologies have led to the development of laser-generated particle accel... more Rapidly evolving laser technologies have led to the development of laser-generated particle accelerators as an alternative to conventional facilities. However, the radiobiological characteristics need to be determined to enhance their applications in biology and medicine. In this study, the radiobiological effects of ultrashort pulsed electron beam (UPEB) and X-ray radiation in human lung fibroblasts (MRC-5 cell line) exposed to doses of 0.1, 0.5, and 1 Gy are compared. The changes of γH2AX foci number as a marker of DNA double-strand breaks (DSBs) were analyzed. In addition, the micronuclei induction and cell death via apoptosis were studied. We found that the biological action of UPEB-radiation compared to X-rays was characterized by significantly slower γH2AX foci elimination (with a dose of 1 Gy) and strong apoptosis induction (with doses of 0.5 and 1.0 Gy), accompanied by a slight increase in micronuclei formation (dose of 1 Gy). Our data suggest that UPEB radiation produces mo...

Research paper thumbnail of Ochratoxin A induces global DNA hypomethylation and oxidative stress in neuronal cells in vitro

Research paper thumbnail of Genotoxic potential of selected medicinal plant extracts in human whole blood cultures

Journal of Herbmed Pharmacology

Introduction: Many plant-derived products despite wide usage are not scientifically evaluated for... more Introduction: Many plant-derived products despite wide usage are not scientifically evaluated for their safety and efficacy. Therefore, in the present study, we aimed to evaluate the cytotoxic and genotoxic activities of Polygonum aviculare L., Equisetum arvense L., Plantago lanceolata L. and Artemisia absinthium L. ethanolic extracts in human white blood cells. Methods: Cell viability was assayed by trypan blue exclusion method, while the genotoxicity was tested by cytokinesis-block micronucleus (CBMN) assay upon cells stimulation with noncytotoxic concentrations of the plant extracts. Results: None of the plant extracts showed high cytotoxic activity. At the same time, only extract of P. lanceolata did not present any mutagenic activity, while E. arvense, P. aviculare and A. absinthium were clearly genotoxic. Conclusion: Caution is advice in the case of long-term use of E. arvense, P. aviculare and A. absinthium herbal medicines by population.

Research paper thumbnail of Increased Yield of Residual γH2AX Foci in p53-Deficient Human Lung Carcinoma Cells Exposed to Subpicosecond Beams of Accelerated Electrons

Bulletin of Experimental Biology and Medicine

Research paper thumbnail of Raw Data of Generated Dose-Response Curves

Research paper thumbnail of Incidence and Risk Factors of Acute Leukemias in Armenia: A Population-Based Study

Asian Pacific Journal of Cancer Prevention

80% of all pediatric leukemias with a peak incidence in age group <15 years old and a second peak... more 80% of all pediatric leukemias with a peak incidence in age group <15 years old and a second peak after 50 years of age (

Research paper thumbnail of Improving VAE based molecular representations for compound property prediction

Journal of Cheminformatics

Collecting labeled data for many important tasks in chemoinformatics is time consuming and requir... more Collecting labeled data for many important tasks in chemoinformatics is time consuming and requires expensive experiments. In recent years, machine learning has been used to learn rich representations of molecules using large scale unlabeled molecular datasets and transfer the knowledge to solve the more challenging tasks with limited datasets. Variational autoencoders are one of the tools that have been proposed to perform the transfer for both chemical property prediction and molecular generation tasks. In this work we propose a simple method to improve chemical property prediction performance of machine learning models by incorporating additional information on correlated molecular descriptors in the representations learned by variational autoencoders. We verify the method on three property prediction tasks. We explore the impact of the number of incorporated descriptors, correlation between the descriptors and the target properties, sizes of the datasets etc. Finally, we show th...

Research paper thumbnail of Screening of phytochemicals, toxicities, and activities of three Dillenia species

Journal of Herbmed Pharmacology

Introduction: Plants containing β-sitosterol and oleamide are important for various diseases. So,... more Introduction: Plants containing β-sitosterol and oleamide are important for various diseases. So, Dillenia indica, D. obovata, and D. pentagyna were investigated for phytochemicals, cytotoxicity and genotoxicity levels on peripheral blood mononuclear cells (PBMCs) and Hela cells. The protective effect of D. pentagyna extract on a HepG2 cell line was also investigated. Methods: Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) were used for phytochemical analysis. 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction (MTT) and comet assays were performed for toxicity testing and protective effects against DNA oxidative damage. Results: The major components were oleamide and β-sitosterol at 38.464-58.247% and 5.585- 6.887% with concentration and quantity of β-sitosterol at 0.2-0.37 mg/mL and 0.42-0.964 mg/g leaf. The D. indica, D. obovata, and D. pentagyna toxicities on PBMCs showed IC50 values at >430, &gt...

Research paper thumbnail of BARTSmiles: Generative Masked Language Models for Molecular Representations

Cornell University - arXiv, Nov 29, 2022

We discover a robust self-supervised strategy tailored towards molecular representations for gene... more We discover a robust self-supervised strategy tailored towards molecular representations for generative masked language models through a series of tailored, in-depth ablations. Using this pre-training strategy, we train BARTSmiles, a BART-like model with an order of magnitude more compute than previous self-supervised molecular representations. In-depth evaluations show that BARTSmiles consistently outperforms other self-supervised representations across classification, regression, and generation tasks setting a new state-of-the-art on 11 tasks. We then quantitatively show that when applied to the molecular domain, the BART objective learns representations that implicitly encode our downstream tasks of interest. For example, by selecting seven neurons from a frozen BARTSmiles, we can obtain a model having performance within two percentage points of the full fine-tuned model on task Clintox. Lastly, we show that standard attribution interpretability methods, when applied to BARTSmiles, highlight certain substructures that chemists use to explain specific properties of molecules. The code and the pretrained model are publicly available.

Research paper thumbnail of Colony-Forming Ability and Residual Foci of DNA Repair Proteins in Human Lung Fibroblasts Irradiated with Subpicosecond Beams of Accelerated Electrons

Bulletin of Experimental Biology and Medicine, 2021

We performed a comparative study of the colony-forming ability and the number of residual foci of... more We performed a comparative study of the colony-forming ability and the number of residual foci of DNA repair proteins in cultured human lung fibroblasts (MRC-5 cell line) after exposure to subpicosecond beams of accelerated electrons with an energy of 3.6 MeV and quasi-continuous radiation (accelerated electrons with an energy of 4 MeV and X-rays). The yield of damages causing reproductive cell death after pulsed subpicosecond radiation exposure was higher by ~1.8 times than after quasi-continuous radiation exposure. The quantitative yield of residual γH2AX foci (phosphorylated H2AX histone, a protein marker of DNA double breaks) in cells irradiated with subpicosecond beams of accelerated electrons was shown to be ~2.0- 2.5-fold higher than in cells irradiated with quasi-continuous beams of accelerated electrons.

Research paper thumbnail of Synthesis, characterization and toxicity studies of pyridinecarboxaldehydes and L-tryptophan derived Schiff bases and corresponding copper (II) complexes

F1000Research, 2016

Schiff bases and their metal-complexes are versatile compounds exhibiting a broad range of biolog... more Schiff bases and their metal-complexes are versatile compounds exhibiting a broad range of biological activities and thus actively used in the drug development process. The aim of the present study was the synthesis and characterization of new Schiff bases and their copper (II) complexes, derived from L-tryptophan and isomeric (2-; 3-; 4-) pyridinecarboxaldehydes, as well as the assessment of their toxicity in vitro. The optimal conditions of the Schiff base synthesis resulting in up to 75-85% yield of target products were identified. The structure-activity relationship analysis indicated that the location of the carboxaldehyde group at 2-, 3- or 4-position with regard to nitrogen of the pyridine ring in aldehyde component of the L-tryptophan derivative Schiff bases and corresponding copper complexes essentially change the biological activity of the compounds. The carboxaldehyde group at 2- and 4-positions leads to the higher cytotoxic activity, than that of at 3-position, and the p...

Research paper thumbnail of Influence of aflatoxin B1 on copy number variants in human leukocytes in vitro

Molecular Cytogenetics, Apr 9, 2015

Background: Aflatoxin B1 (AFB1) is a mycotoxin produced by Aspergillus spec. The latter are world... more Background: Aflatoxin B1 (AFB1) is a mycotoxin produced by Aspergillus spec. The latter are worldwide contaminants of food with mutagenic and carcinogenic activities in animals and humans. AFB1 was shown to have deleterious effects on metabolism of eukaryotes in many model systems, including the ability to inhibit DNA replication. An agent that disturbs DNA replication may also have the potential to induce de novo DNA copy number variations (CNVs). Results: Blood samples of three clinically healthy carriers were treated in vitro with AFB1 and chromosome preparations were subjected to parental origin determination fluorescence in situ hybridization (pod-FISH). Probes able to visualize CNVs in 8p21.2 and 15q11.2 were applied. In this setting here for the first time an influence of AFB1 on molecular-cytogenetically detectable CNVs could be shown. Conclusions: The obtained results indicate that: (i) pod-FISH is a single cell directed, sensitive and suitable method for the analysis of mutagen induced CNVs, (ii) AFB1 has the potential to induce in vitro instability of known CNVs in human leukocytes.

Research paper thumbnail of Gender differences in DNA damage/repair after laser-generated ultrafast electron beam irradiation

International Journal of Radiology & Radiation Therapy

The laser-driven particle acceleration technology has been developed over the last decade as a po... more The laser-driven particle acceleration technology has been developed over the last decade as a possible alternative to conventional particle accelerators. The significantly smaller size and cost, as well as the precise beam orientation compared with conventional cyclotrons ensure the potential application of laser-driven particle irradiation in imaging and treatment of cancerous cells. However, the radiobiological studies on laser-generated particle bunches are still required to promote its application in clinical practice. The aim of the work was to investigate the laser-generated ultrafast electron beam irradiation effect on DNA damage and repair in human peripheral blood mononuclear cells (PBMCs) with the respect to gender-specific radiosensitivity. The single cell gel-electrophoresis (comet) assay was used to analyze the level of DNA damage/repair. The level of DNA damages after irradiation was almost 3 times higher in female PBMCs, than that of in male PBMCs. The reparation capacity in female PBMCs was also lower, compared to male PBMCs. So, the difference between male and female DNA damage/repair response to laser-generated ultrafast electron beam irradiation was investigated. The gender bias in radiosensitivity was revealed, demonstrating higher female sensitivity to irradiation.

Research paper thumbnail of AREAL low energy electron beam applications in life and materials sciences

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2016

The AREAL laser-driven RF gun provides 2-5 MeV energy ultrashort electron pulses for experimental... more The AREAL laser-driven RF gun provides 2-5 MeV energy ultrashort electron pulses for experimental study in life and materials sciences. We report the first experimental results of the AREAL beam application in the study of molecular-genetic effects, silicon-dielectric structures, ferroelectric nanofilms, and single crystals for scintillators.

Research paper thumbnail of Radioprotective effect of creatine on DNA damage in peripheral blood mononuclear cells and adaptive properties of brain and liver creatine-creatine kinase system of the rats

"Radiation and Risk" Bulletin of the National Radiation and Epidemiological Registry

Research paper thumbnail of Low-Energy Laser-Driven Ultrashort Pulsed Electron Beam Irradiation-Induced Immune Response in Rats

International Journal of Molecular Sciences

The development of new laser-driven electron linear accelerators, providing unique ultrashort pul... more The development of new laser-driven electron linear accelerators, providing unique ultrashort pulsed electron beams (UPEBs) with low repetition rates, opens new opportunities for radiotherapy and new fronts for radiobiological research in general. Considering the growing interest in the application of UPEBs in radiation biology and medicine, the aim of this study was to reveal the changes in immune system in response to low-energy laser-driven UPEB whole-body irradiation in rodents. Forty male albino Wistar rats were exposed to laser-driven UPEB irradiation, after which different immunological parameters were studied on the 1st, 3rd, 7th, 14th, and 28th day after irradiation. According to the results, this type of irradiation induces alterations in the rat immune system, particularly by increasing the production of pro- and anti-inflammatory cytokines and elevating the DNA damage rate. Moreover, such an immune response reaches its maximal levels on the third day after laser-driven U...

Research paper thumbnail of The role of women scientists in the development of ultrashort pulsed laser technology-based biomedical research in Armenia

International Journal of Radiation Biology

Research paper thumbnail of Helix pomatia albumen gland water soluble protein extract as powerful antiaging agent

Research paper thumbnail of DNA double-strand break repair efficiency in cancer cells exposed to laser-driven ultrashort electron beams

Research paper thumbnail of Low Repair Capacity of DNA Double-Strand Breaks Induced by Laser-Driven Ultrashort Electron Beams in Cancer Cells

International Journal of Molecular Sciences

Laser-driven accelerators allow to generate ultrashort (from femto- to picoseconds) high peak dos... more Laser-driven accelerators allow to generate ultrashort (from femto- to picoseconds) high peak dose-rate (up to tens of GGy/s) accelerated particle beams. However, the radiobiological effects of ultrashort pulsed irradiation are still poorly studied. The aim of this work was to compare the formation and elimination of γH2AX and 53BP1 foci (well known markers for DNA double-strand breaks (DSBs)) in Hela cells exposed to ultrashort pulsed electron beams generated by Advanced Research Electron Accelerator Laboratory (AREAL) accelerator (electron energy 3.6 MeV, pulse duration 450 fs, pulse repetition rates 2 or 20 Hz) and quasi-continuous radiation generated by Varian accelerator (electron energy 4 MeV) at doses of 250–1000 mGy. Additionally, a study on the dose–response relationships of changes in the number of residual γH2AX foci in HeLa and A549 cells 24 h after irradiation at doses of 500–10,000 mGy were performed. We found no statistically significant differences in γH2AX and 53BP1...

Research paper thumbnail of Laser-Driven Ultrashort Pulsed Electron Beam Radiation at Doses of 0.5 and 1.0 Gy Induces Apoptosis in Human Fibroblasts

International Journal of Molecular Sciences

Rapidly evolving laser technologies have led to the development of laser-generated particle accel... more Rapidly evolving laser technologies have led to the development of laser-generated particle accelerators as an alternative to conventional facilities. However, the radiobiological characteristics need to be determined to enhance their applications in biology and medicine. In this study, the radiobiological effects of ultrashort pulsed electron beam (UPEB) and X-ray radiation in human lung fibroblasts (MRC-5 cell line) exposed to doses of 0.1, 0.5, and 1 Gy are compared. The changes of γH2AX foci number as a marker of DNA double-strand breaks (DSBs) were analyzed. In addition, the micronuclei induction and cell death via apoptosis were studied. We found that the biological action of UPEB-radiation compared to X-rays was characterized by significantly slower γH2AX foci elimination (with a dose of 1 Gy) and strong apoptosis induction (with doses of 0.5 and 1.0 Gy), accompanied by a slight increase in micronuclei formation (dose of 1 Gy). Our data suggest that UPEB radiation produces mo...

Research paper thumbnail of Ochratoxin A induces global DNA hypomethylation and oxidative stress in neuronal cells in vitro

Research paper thumbnail of Genotoxic potential of selected medicinal plant extracts in human whole blood cultures

Journal of Herbmed Pharmacology

Introduction: Many plant-derived products despite wide usage are not scientifically evaluated for... more Introduction: Many plant-derived products despite wide usage are not scientifically evaluated for their safety and efficacy. Therefore, in the present study, we aimed to evaluate the cytotoxic and genotoxic activities of Polygonum aviculare L., Equisetum arvense L., Plantago lanceolata L. and Artemisia absinthium L. ethanolic extracts in human white blood cells. Methods: Cell viability was assayed by trypan blue exclusion method, while the genotoxicity was tested by cytokinesis-block micronucleus (CBMN) assay upon cells stimulation with noncytotoxic concentrations of the plant extracts. Results: None of the plant extracts showed high cytotoxic activity. At the same time, only extract of P. lanceolata did not present any mutagenic activity, while E. arvense, P. aviculare and A. absinthium were clearly genotoxic. Conclusion: Caution is advice in the case of long-term use of E. arvense, P. aviculare and A. absinthium herbal medicines by population.