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1.
Int J Radiat Biol ; : 1-16, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38683545

RESUMO

PURPOSE: Creatine (Cr) and l-arginine are naturally occurring guanidino compounds, commonly used as ergogenic dietary supplements. Creatine and l-arginine exhibit also a number of non-energy-related features, such as antioxidant, anti-apoptotic, and anti-inflammatory properties, which contribute to their protective action against oxidative stress (OS). In this regard, there are a number of studies emphasizing the protective effect of Cr against OS, which develops in the process of aging, increased physical loads as part of athletes' workouts, as well as a number of neurological diseases and toxic effects associated with xenobiotics and UV irradiation. Against this backdrop, and since ionizing radiation causes OS in cells, leading to radiotoxicity, there is an increasing interest to understand whether Cr has the full potential to serve as an effective radioprotective agent. The extensive literature search did not provide any data on this issue. In this narrative review, we have summarized some of our own experimental data published over the last years addressing the respective radioprotective effects of Cr. Next, we have additionally reviewed the existing data on the radiomodifying effects of l-arginine presented earlier by other research groups. CONCLUSIONS: Creatine possesses significant radioprotective potential including: (1) radioprotective effect on the survival rate of rats subjected to acute whole-body X-ray irradiation in a LD70/30 dose of 6.5 Gy, (2) radioprotective effect on the population composition of peripheral blood cells, (3) radioprotective effect on the DNA damage of peripheral blood mononuclear cells, (4) radioprotective effect on the hepatocyte nucleus-nucleolar apparatus, and (5) radioprotective effect on the brain and liver Cr-Cr kinase systems of the respective animals. Taking into account these cytoprotective, gene-protective, hepatoprotective and energy-stimulating features of Cr, as well as its significant radioprotective effect on the survival rate of rats, it can be considered as a potentially promising radioprotector for further preclinical and clinical studies. The review of the currently available data on radiomodifying effects of l-arginine has indicated its significant potential as a radioprotector, radiomitigator, and radiosensitizer. However, to prove the effectiveness of arginine (Arg) as a radioprotective agent, it appears necessary to expand and deepen the relevant preclinical studies, and, most importantly, increase the number of proof-of-concept clinical trials, which are evidently lacking as of now.

2.
Vet Microbiol ; 284: 109835, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37515978

RESUMO

African swine fever virus (ASFV) can accumulate and survive in leeches for a long time. The reasons for the survival of ASFV in leeches are not entirely clear. Here, we elucidate the virus survival pathway in infected leeches. One of the questions reported previously is addressed in this article. How the virus concentration in the body of the leech is equal to or higher than in the water infected with ASFV? Examination of blood swallowed by leeches reveals that the blood cells retain their morphological characteristics for several weeks. It can explain the long-term persistence of the high levels of ASFV in the leeches that ingested ASFV-infected pig blood. qRT-PCR assay showed the transcription of ASFV genes in infected leeches. However, the infectious particles of the virus measured by HADU haven't increased. Quantitative studies of the ASFV revealed a high content of both viral genes and infectious particles in the skin of leeches compared with other body parts. Electron microscopy analysis revealed the ability of the ASFV to effectively bind to the skin surface of the leeches, which explained the high concentrations of ASFV in the leeches' skin. A significant difference in the transcriptional activity between early and late viral genes indicates that the virus entered the initial stage of replication, but for some reason failed to complete it, which is typical of abortive infections.


Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Sanguessugas , Doenças dos Suínos , Suínos , Animais , Vírus da Febre Suína Africana/genética , Sanguessugas/genética , Genes Virais , Replicação Viral , Doenças dos Suínos/genética
3.
Phys Med ; 104: 174-187, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36463582

RESUMO

At the Photo Injector Test facility at DESY in Zeuthen (PITZ), an R&D platform for electron FLASH and very high energy electron radiation therapy and radiation biology is being prepared (FLASHlab@PITZ). The beam parameters available at PITZ are worldwide unique. They are based on experiences from 20 + years of developing high brightness beam sources and an ultra-intensive THz light source demonstrator for ps scale electron bunches with up to 5 nC bunch charge at MHz repetition rate in bunch trains of up to 1 ms length, currently 22 MeV (upgrade to 250 MeV planned). Individual bunches can provide peak dose rates up to 1014 Gy/s, and 10 Gy can be delivered within picoseconds. Upon demand, each bunch of the bunch train can be guided to a different transverse location, so that either a "painting" with micro beams (comparable to pencil beam scanning in proton therapy) or a cumulative increase of absorbed dose, using a wide beam distribution, can be realized at the tumor. Full tumor treatment can hence be completed within 1 ms, mitigating organ movement issues. With extremely flexible beam manipulation capabilities, FLASHlab@PITZ will cover the current parameter range of successfully demonstrated FLASH effects and extend the parameter range towards yet unexploited short treatment times and high dose rates. A summary of the plans for FLASHlab@PITZ and the status of its realization will be presented.


Assuntos
Elétrons , Neoplasias , Humanos , Radiobiologia
4.
Int J Mol Sci ; 23(12)2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35743135

RESUMO

Anemia is a commonly observed consequence of whole-body exposure to a dose of X-ray or gamma irradiation of the order of the mean lethal dose in mammals, and it is an important factor for the determination of the survival of animals. The aim of this study was to unravel the effect of laser-driven ultrashort pulsed electron beam (UPEB) irradiation on the process of erythropoiesis and the redox state in the organism. Wistar rats were exposed to laser-driven UPEB irradiation, after which the level of oxidative stress and the activities of different antioxidant enzymes, as well as blood smears, bone marrow imprints and sections, erythroblastic islets, hemoglobin and hematocrit, hepatic iron, DNA, and erythropoietin levels, were assessed on the 1st, 3rd, 7th, 14th, and 28th days after irradiation. Despite the fact that laser-driven UPEB irradiation requires quite low doses and repetition rates to achieve the LD50 in rats, our findings suggest that whole-body exposure with this new type of irradiation causes relatively mild anemia in rats, with subsequent fast recovery up to the 28th day. Moreover, this novel type of irradiation causes highly intense processes of oxidative stress, which, despite being relatively extinguished, did not reach the physiologically stable level even at the 28th day after irradiation due to the violations in the antioxidant system of the organism.


Assuntos
Elétrons , Eritropoese , Animais , Antioxidantes/farmacologia , Lasers , Mamíferos , Estresse Oxidativo , Ratos , Ratos Wistar
6.
Int J Radiat Biol ; 98(3): 308-313, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34505825

RESUMO

PURPOSE: To describe the contribution of Margarita Malakyan to the development of radiation biology in Armenia and how her multidisciplinary collaboration with chemists, physicists and biologists around the world led to the development of radioprotectors and radiosensitizers of different origins. CONCLUSION: Margarita Malakyan was a very active and initiative woman, a radiobiologist, whose hard work and enthusiasm led to the establishment of a very constructive scientific network and to the development of newly synthesized metal compounds. During her short but very productive life, the synthesis, characterization, as well as toxicity and radioprotective studies of different compounds led to the suggestion of a number of metal complexes of Schiff bases as effective radioprotective agents and radiosensitizers.

7.
Int J Radiat Biol ; 98(3): 489-495, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34623213

RESUMO

PURPOSE: To describe the contribution of women scientists in the development of biomedical studies conducted on research facilities based on the ultrashort pulsed laser technologies in Armenia. CONCLUSION: Given the opportunities provided by the ultrashort pulsed laser driven two-photon microscopy and electron beam linac facilities at CANDLE Synchrotron Research Institute, the Armenian women scientists initiated and conducted interdisciplinary research to understand of the biomedical effects of ultrashort pulsed electron beam irradiation, as well as to experience and apply the advantages of the two-photon microscopy in their fields of research. Women scientists had a crucial role and unique impact in the development of ultrashort pulsed laser technology-based biomedical studies in Armenia.


Assuntos
Pesquisa Biomédica , Lasers , Armênia , Feminino , Humanos , Aceleradores de Partículas , Tecnologia
8.
Int J Mol Sci ; 22(21)2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34768958

RESUMO

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 UPEB whole-body irradiation, showing partial recovery on subsequent days with a total recovery on the 28th day. The results of this study provide valuable insight into the effect of laser-driven UPEB whole-body irradiation on the immune system of the animals and support further animal experiments on the role of this novel type of irradiation.


Assuntos
Elétrons/efeitos adversos , Imunidade/efeitos da radiação , Irradiação Corporal Total/efeitos adversos , Animais , Medula Óssea/imunologia , Medula Óssea/patologia , Medula Óssea/efeitos da radiação , Citocinas/biossíntese , Dano ao DNA , Reparo do DNA/efeitos da radiação , Lasers/efeitos adversos , Leucócitos/imunologia , Leucócitos/patologia , Leucócitos/efeitos da radiação , Masculino , Aceleradores de Partículas , Radiobiologia , Ratos , Ratos Wistar
9.
Pharmgenomics Pers Med ; 14: 1347-1368, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34707385

RESUMO

PURPOSE: The current study aimed to investigate in an Armenian population the levels of pattern recognition molecules (PRMs) of lectin complement pathway (LCP), MBL (mannan-binding lectin) and M-ficolin in plasma in ischemic stroke (IS), and the possible association of 11 single nucleotide polymorphisms (SNPs) in MBL2, FCN1 and FCN2 genes. PATIENTS AND METHODS: A total of 122 patients with IS and 150 control subjects were included in this study. Immunofluorometric assays (TRIFMAs) and real-time polymerase chain reactions with TaqMan probes were conducted. RESULTS: According to the results, the levels of M-ficolin in IS patients are significantly higher than in control subjects, and the MBL2 rs11003125 and rs12780112 SNPs, as well as MBL2 rs12780112*T and FCN1 rs10120023*T minor alleles (MAs) are negatively associated with the risk of IS. Further, MBL2 rs11003125 and rs1800450 SNPs and the carriage of their MAs, as well as FCN1 rs2989727 SNP and the carriage of FCN1 rs10120023*T MA significantly alter plasma MBL and M-ficolin levels in IS patients, respectively. Five common haplotypes in MBL2 gene and three common haplotypes in FCN1 and FCN2 genes were revealed, among which CGTC was negatively associated with IS and decreasing MBL plasma levels in IS. CONCLUSION: In conclusion, we suggest that LCP PRMs are associated with the risk of developing IS, and may also participate in pathological events leading to post-ischemic brain damage. This study emphasizes the important contribution of alterations of LCP PRMs on genomic and proteomic levels to the pathomechanisms of ischemic stroke, at least in an Armenian population.

10.
Radiat Res ; 196(6): 658-667, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34478547

RESUMO

Recently, a new technology of low-energy ultrashort-pulsed electron beam (UPEB) accelerators has been developed opening new directions for radiobiology and biomedical research. The purpose of this study was to reveal the lethal dose, LD50 (lethal dose, 50%) delivered by low-energy UPEB whole-body exposure on an organismal level. Wistar rats were exposed to low-energy UPEB whole-body irradiation with different doses and pulse repetition rates to find the LD50 and in silico computer simulations were performed to conduct numerical dose calculations. Survival rate, body weight and water consumption were monitored over the 30-day observation period postirradiation. The LD50 was observed after a 2 Gy dose and pulse repetition rate of 2 Hz. In this group, 50% of the animals survived 30 days postirradiation. The groups of animals exposed to low-energy UPEB radiation at higher doses and pulse repetition rates demonstrated higher mortality rates. We demonstrated that the LD50 dose for the low-energy UPEB whole body irradiation in Wistar rats corresponds to 2 Gy with a pulse repetition rate of 2 Hz. Moreover, we showed that the pulse repetition rate is a very important parameter in the experiments with UPEB and should be assessed in the experiments with such kind of novel irradiation sources.


Assuntos
Lasers , Irradiação Corporal Total , Animais , Simulação por Computador , Elétrons , Dose Letal Mediana , Masculino , Ratos , Ratos Wistar
11.
PLoS One ; 16(6): e0253553, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34143847

RESUMO

For the last years, copper complexes have been intensively implicated in biomedical research as components of cancer treatment. Herewith, we provide highlights of the synthesis, physical measurements, structural characterization of the newly developed Cu(II) chelates of Schiff Bases, Cu(Picolinyl-L-Tryptopahanate)2, Cu(Picolinyl-L-Tyrosinate)2, Cu(Isonicotinyl-L-Tyrosinate)2, Cu(Picolinyl-L-Phenylalaninate)2, Cu(Nicotinyl-L-Phenylalaninate)2, Cu(Isonicotinyl-L-Phenylalaninate)2, and their radioenhancement capacity at kV and MV ranges of irradiation of human lung carcinoma epithelial cells in vitro. The methods of cell growth, viability and proliferation were used. All compounds exerted very potent radioenhancer capacities in the irradiated lung carcinoma cells at both kV and MV ranges in a 100 µM concentration. At a concentration of 10 µM, only Cu(Picolinyl-L-Tyrosinate)2, Cu(Isonicotinyl-L-Tyrosinate)2, Cu(Picolinyl-L-Phenylalaninate)2 possessed radioenhancer properties at kV and MV ranges. Cu(Picolinyl-L-Tryptophanate)2 showed radioenhancer properties only at kV range. Cu(Nicotinyl-L-Phenylalaninate)2 and Cu(Isonicotinyl-L-Phenylalaninate)2 showed remarkable radioenhancer activity only at MV range. All compounds acted in dose-dependent manner at both tested energy ranges. These copper (II) compounds, in combination with 1 Gy irradiation at either 120 kV or 6 MV, are more efficient at delaying cell growth of lung cancer cells and at reducing cell viability in vitro than the irradiation administered alone. Thus, we have demonstrated that the studied copper compounds have a good potential for radioenhancement.


Assuntos
Complexos de Coordenação/química , Cobre/química , Neoplasias Pulmonares/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Bases de Schiff/química , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Humanos
12.
Exp Gerontol ; 146: 111244, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33454353

RESUMO

Accounting for increasingly developed population aging and dramatic elevation of aging-related severe disorders worldwide, search of the efficient antiaging agents is becoming one of the urgent problems of contemporary biomedical science. The aim of current study was to reveal the potential protective effects of water-soluble proteins extracted from albumen gland of snails against aging processes. We evaluated the antioxidant effect of the extract in 20 older adult rats in vivo and on 60 human blood samples ex vivo at the cellular level under physiological and oxidative stress conditions using the methods of spectrophotometric analysis, two-photon imaging and cell viability assay. The in vivo animal experiments showed significant increase in the levels of catalase and superoxide dismutase in treated older adult rats, compared to non-treated group. The ex vivo studies involving three human groups (young, middle aged and older adult), demonstrated that the extract has no effect on the cell viability, moreover significantly increases the number of erythrocytes, decreases age-related oxidative stress and the percentage of hemolysis of erythrocytes by aging. Thus, the snails albumen gland protein extract can be considered as effective natural antioxidative antiaging agent in prevention of aging-related pathological processes associated with oxidative stress.


Assuntos
Antioxidantes , Água , Animais , Antioxidantes/farmacologia , Catalase/metabolismo , Estresse Oxidativo , Ratos , Superóxido Dismutase/metabolismo
13.
Int J Mol Sci ; 21(24)2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33327380

RESUMO

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 foci yields at 1 h after exposure to 2 Hz ultrashort pulse vs. quasi-continuous radiations. In contrast, 20 Hz ultrashort pulse irradiation resulted in 1.27-fold higher foci yields as compared to the quasi-continuous one. After 24 h of pulse irradiation at doses of 500-10,000 mGy the number of residual γH2AX foci in Hela and A549 cells was 1.7-2.9 times higher compared to that of quasi-continuous irradiation. Overall, the obtained results suggest the slower repair rate for DSBs induced by ultrashort pulse irradiation in comparison to DSBs induced by quasi-continuous irradiation.


Assuntos
Quebras de DNA de Cadeia Dupla/efeitos da radiação , Lasers , Radiação Ionizante , Células A549 , Reparo do DNA/efeitos da radiação , Células HeLa , Histonas/genética , Histonas/metabolismo , Humanos , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo
14.
Biomed Opt Express ; 11(7): 3444-3454, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33014543

RESUMO

According to the "oxidative stress theory" of aging, this process is accompanied by a progressive and irreversible accumulation of oxidative damage caused by reactive oxygen species (ROS). This, in turn, has a deleterious impact on molecular mechanisms in aging thereby altering the physiological function of the organism, increasing the risk of different aging-related diseases, as well as impacting the life span. The aim of the current study was to investigate oxidative stress in living red blood cells (RBCs) in human aging as an oxidative stress-related pathological condition. Two-photon laser scanning and light microscopy techniques were applied to analyze the oxidative stress in RBCs and the cell viability. Spectrophotometric analyzes were performed to determine the percentage of RBC hemolysis, activities of superoxide dismutase and catalase in RBCs, as well as the ferroxidase activities of ceruloplasmin in blood plasma samples. The studies included three human aging groups, young, middle-aged, and elderly. According to the results, the two-photon fluorescence of carboxy-DCFDA, indicating the intensity of oxidative stress, significantly increase in RBCs by the increase of age (P < 0.05), and these intensities are in statistically significant positive correlation with age (P < 0.001) and a strong negative correlation (P < 0.05) with the activity of catalase in RBCs and ferroxidase activity of ceruloplasmin in plasma. In conclusion, two-photon fluorescent imaging of oxidative stress in human living RBCs is a valuable and accurate method for the determination of aging processes in humans and can be suggested as a novel indicator for human aging processes in individual aging.

15.
BMC Med Genet ; 19(1): 33, 2018 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-29499660

RESUMO

BACKGROUND: Despite the important role of the nerve growth factor in the survival and maintenance of neurons in ischemic stroke, data regarding the relationships between variations in the encoding gene and stroke are lacking. In the present study, we evaluated the association of the functional polymorphisms in NGF (rs6330) and NGFR (rs2072446 and rs734194) genes with ischemic stroke in an Armenian population. METHODS: In total, 370 unrelated individuals of Armenian nationality were enrolled in this study. Genomic DNA samples of patients and healthy controls were genotyped using polymerase chain reaction with sequence-specific primers. RESULTS: The results obtained indicate that the minor allele of rs6330 (P corr = 2.4E-10) and rs2072446 (P corr = 0.02) are significantly overrepresented in stroke group, while the minor allele of rs734194 (P corr = 8.5E-10) was underrepresented in diseased subjects. Single nucleotide polymorphisms in NGF gene (rs6330) and NGFR gene (rs2072446 and rs734194) are associated with the disease. Furthermore, it was shown that the carriage of the NGF rs6330*T minor allele is associated with increased infarct volume and higher risk of recurrent stroke. CONCLUSIONS: In conclusion, our findings suggest that the NGF rs6330*T and NGFR rs2072446*T minor alleles might be nominated as a risk factor for developing ischemic stroke and NGFR rs734194*G minor allele as a protective against this disease at least in Armenian population.


Assuntos
Isquemia Encefálica/genética , Fator de Crescimento Neural/genética , Proteínas do Tecido Nervoso/genética , Polimorfismo de Nucleotídeo Único , Receptores de Fator de Crescimento Neural/genética , Acidente Vascular Cerebral/genética , Adulto , Alelos , Armênia , Isquemia Encefálica/diagnóstico , Estudos de Casos e Controles , Feminino , Frequência do Gene , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Técnicas de Genotipagem , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Acidente Vascular Cerebral/diagnóstico , População Branca/genética
16.
J Clin Pathol ; 71(2): 141-147, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28720568

RESUMO

AIMS: The aim of the current study was to assess the proteolytic activities of collectin-bound MASP-1 and MASP-2 in the blood of patients with ischaemic stroke, as well as the association of their six genetic polymorphisms (rs3203210, rs28945070, rs28945073 in MASP1 gene and rs2273343, rs12711521, rs147270785 in MASP2 gene) with this pathology. METHODS: In total, 250 patients and 300 healthy subjects were involved in this study. MBL-associated serine protease (MASP)-1 and MASP-2 activities were measured using in-house developed immunofluorescent and enzyme-linked immunosorbent assays, respectively. Sequence specific primer PCR was used to study the association of MASP1 and MASP2 genetic polymorphisms with ischaemic stroke. RESULTS: The results obtained demonstrate that the activities of collectin-bound MASP-1 and MASP-2 in patients with ischaemic stroke are significantly higher than those in healthy subjects (p<0.001). According to the data obtained for genotyping, the rs3203210 polymorphism in the MASP1 gene and the rs147270785 polymorphism in the MASP2 gene are associated with ischaemic stroke (p<0.0001). CONCLUSIONS: In conclusion we suggest that the complement lectin pathway serine proteases, MASP-1 and MASP-2, can be associated with ischaemic stroke development risk and may participate in pathological events leading to post-ischaemic brain damage. Moreover rs3203210 and rs147270785 single nucleotide polymorphisms in the MASP1 and MASP2 genes, respectively, are strongly associated with ischaemic stroke, and the minor rs3203210*C and rs147270785*A alleles of these polymorphisms may be considered as protective factors for ischameic stroke, at least in the Armenian population.


Assuntos
Serina Proteases Associadas a Proteína de Ligação a Manose/metabolismo , Polimorfismo de Nucleotídeo Único , Acidente Vascular Cerebral/enzimologia , Acidente Vascular Cerebral/genética , Adulto , Idoso , Armênia , Biomarcadores/sangue , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Feminino , Marcadores Genéticos , Predisposição Genética para Doença , Técnicas de Genotipagem , Humanos , Masculino , Serina Proteases Associadas a Proteína de Ligação a Manose/genética , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Fatores de Risco , Acidente Vascular Cerebral/diagnóstico
17.
J Radiat Res ; 58(6): 894-897, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28992052

RESUMO

Laser-generated electron beams are distinguished from conventional accelerated particles by ultrashort beam pulses in the femtoseconds to picoseconds duration range, and their application may elucidate primary radiobiological effects. The aim of the present study was to determine the dose-rate effect of laser-generated ultrashort pulses of 4 MeV electron beam radiation on DNA damage and repair in human cells. The dose rate was increased via changing the pulse repetition frequency, without increasing the electron energy. The human chronic myeloid leukemia K-562 cell line was used to estimate the DNA damage and repair after irradiation, via the comet assay. A distribution analysis of the DNA damage was performed. The same mean level of initial DNA damages was observed at low (3.6 Gy/min) and high (36 Gy/min) dose-rate irradiation. In the case of low-dose-rate irradiation, the detected DNA damages were completely repairable, whereas the high-dose-rate irradiation demonstrated a lower level of reparability. The distribution analysis of initial DNA damages after high-dose-rate irradiation revealed a shift towards higher amounts of damage and a broadening in distribution. Thus, increasing the dose rate via changing the pulse frequency of ultrafast electrons leads to an increase in the complexity of DNA damages, with a consequent decrease in their reparability. Since the application of an ultrashort pulsed electron beam permits us to describe the primary radiobiological effects, it can be assumed that the observed dose-rate effect on DNA damage/repair is mainly caused by primary lesions appearing at the moment of irradiation.


Assuntos
Dano ao DNA , Reparo do DNA/efeitos da radiação , Elétrons , Ensaio Cometa , Relação Dose-Resposta à Radiação , Humanos , Células K562 , Probabilidade
18.
Brain Circ ; 3(1): 14-20, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-30276299

RESUMO

BACKGROUND AND PURPOSE: Ischemic brain injury induces both functional and structural disarray affecting the blood-brain barrier (BBB) which in return aggravates stroke outcomes. Complement system and its bioactive proteins are important molecular responders to ischemia. C5a protein along with its receptor C5a receptor 1 is a key component of this system with potent pro-inflammatory and chemoattractant properties. The purpose of this study is to investigate the role of C5a protein and its receptor which are believed to participate in the inflammatory response that follows ischemic insult. MATERIALS AND METHODS: To mimic an ischemic in vivo event in which C5a may contact brain endothelial cells after injury, we studied oxygen-glucose deprivation (OGD) followed by reperfusion in brain microvascular endothelial cells (b.End. 3) by only added C5a at the time of reperfusion. Cell death and viability were estimated by trypan blue and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, respectively. Tight junction protein zonula occluden (ZO-1) levels were analyzed by Western blot analysis, and nitric oxide (NO) was assessed using the Griess reagent. RESULTS: Brain-derived endothelial cell was susceptible to OGD-induced injury in a duration-dependent manner as was the presence of ZO-1 protein. However, the addition of C5a protein had no notable effects even when used at high concentrations up to 100 nM. While OGD led to reduction in ZO-1 protein levels, no change was seen following the addition of C5a. Finally, OGD led unexpectedly to small decreases in NO generation, but this was again unaltered by C5a. CONCLUSIONS: Our study suggests that complement system protein C5a may not have a direct role in the disruption of BBB, following brain ischemia. This is in contrary with previous literature that suggests a possible role of this protein in the inflammatory response to ischemia.

19.
Biomed Opt Express ; 8(12): 5834-5846, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29296508

RESUMO

Red blood cells (RBCs) are known to be the most suitable cells to study oxidative stress, which is implicated in the etiopathology of many human diseases. The goal of the current study was to develop a new effective approach for assessing oxidative stress in human living RBCs using two-photon microscopy. To mimic oxidative stress in human living RBCs, an in vitro model was generated followed by two-photon microscopy imaging. The results revealed that oxidative stress is clearly visible on the two-photon microscopy images of RBCs under oxidative stress compared to no fluorescence in controls (P<0.0001). This novel approach for oxidative stress investigation in human living RBCs could efficiently be applied in clinical research and antioxidant compounds testing.

20.
Acta Crystallogr D Biol Crystallogr ; 66(Pt 8): 901-8, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20693689

RESUMO

Modern X-ray structure analysis and advances in high-throughput robotics have allowed a significant increase in the number of conditions screened for a given sample volume. An efficient evaluation of the increased amount of crystallization trials in order to identify successful experiments is now urgently required. A novel approach is presented for the visualization of crystallization experiments using fluorescence from trace amounts of a nonspecific dye. The fluorescence images obtained strongly contrast protein crystals against other phenomena, such as precipitation and phase separation. Novel software has been developed to quantitatively evaluate the crystallization outcome based on a biophysical metric correlated with voxel protein concentration. In >1500 trials, 85.6% of the successful crystallization experiments were correctly identified, yielding a 50% reduction in the number of 'missed hits' compared with current automated approaches. The use of the method in the crystallization of three previously uncharacterized proteins from the malarial parasite Plasmodium falciparum is further demonstrated.


Assuntos
Naftalenossulfonato de Anilina/análise , Cristalografia por Raios X/métodos , Animais , Cristalização , Endopeptidase K/química , Muramidase/química , Plasmodium falciparum/enzimologia , Software
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