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Essential hypertension (EH) is a multifactorial, polygenic condition, and is one of the most important comorbidities that contributes to stroke, myocardial infarction, cardiac failure, and renal failure. The continuous increasing rate of morbidity and mortality associated with EH presents an unmet need of population-based studies to explore pathophysiology as well as newer strategies for better diagnosis, prognosis and treatment. This study aimed to determine genotype and allele frequencies of A1166C polymorphism of AT1R gene in Indian patients with EH and correlated with serum levels of Angiotensin II. A total of 200 patients with EH and 200 age- and gender-matched control individuals were included in this study from the General Medicine Department Outpatient at Narayana Medical College and Hospital, Nellore, Andhra Pradesh, India. Patients with systolic blood pressure (SBP) ≥ 140 mmHg and/or diastolic blood pressure (DBP) ≥ 90 mmHg were considered as hypertensive. The findings of this study revealed significantly increased risk of C/A heterozygote and allele C in both men and women. Moreover, both men and women patients with EH showed higher serum levels of Angiotensin II with C/A as well as AA genotypes. These findings indicate a significant association of 1166 C/A polymorphism of the AT1R gene with increased risk of hypertension in Indian population.
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Essential hypertension (EH) is a multifactorial and complex disease with high rate of incidence and associated co-morbidities. Previous studies do not provide unanimous results for the risk of hypertension and association with Fok I genotype frequency and serum vitamin D levels. Hence, this study was undertaken to determine the status of Fok I vitamin D receptor (VDR) gene polymorphism along with vitamin D levels and blood pressure in patients with EH. Four hundred (200 controls and 200 cases of essential hypertension) participants from general Indian population were enrolled in this study. Peripheral blood samples were collected for genotyping Fok I-VDR gene polymorphism using PCR-RFLP method whereas 25-OH vitamin D levels in serum were quantified using high performance liquid chromatography (HPLC). Significantly reduced 25-OH vitamin D levels were observed in patients with EH (24.04 ± 8.62 vs 50.46 ± 15.46) compared to control subjects (p = 0.0001). Homozygous recessive genotype 'ff' frequency was increased by 8.06 fold (CI: 3.71-17.47, p = 0.0001) in patients with EH compared to dominant 'FF' genotype frequency. In conclusion, recessive 'ff' genotype frequency correlates with reduced serum vitamin D levels and results in significantly increased systolic and diastolic blood pressures leading to predisposition of EH.
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Single nucleotide polymorphisms (SNPs) in adiponectin gene [rs1501299 (+276G/T) and rs266729 (-11377C/G)] and one SNP of leptin gene [rs7799039 (-2548G/A)] are known to influence plasma levels of adiponectin and leptin respectively. Literature is scarce on the association of adiponectin gene polymorphism rs266729 with breast cancer. The present study was taken up to study these polymorphisms and their association with breast cancer. Ninety-three patients diagnosed with malignant breast cancer were included as cases along with 186 age matched healthy controls. Adiponectin +276G/T, -11377C/G and leptin -2548G/A polymorphism were studied using polymerase chain reaction (PCR) based restriction fragment length polymorphism (RFLP). Adipokine levels in blood were measured using enzyme linked immunosorbent assay. Adiponectin +276G/T and leptin -2548G/A showed a significant increased risk for breast cancer even after adjusting for confounding variables like present age, age at menarche, age at first child birth and age at menopause. In the subset analysis, based on menopausal state, stronger association was observed between SNP in adiponectin gene +276G/T with the breast cancer in post-menopausal women after adjusting for all other variables. No association was found with adiponectin -11377C/G. No association of the gene polymorphisms with adipokine levels was observed. Also, no significant association was seen for the effect of gene-environment interaction i.e. presence of polymorphism with obesity and menopausal state for any of the SNPs studied. Adiponectin +276G/T is strongly associated with breast cancer in postmenopausal women while leptin -2548G/A polymorphisms is significantly associated with breast cancer irrespective of the menopausal state in south Indian subjects.
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Adiponectina/genética , Neoplasias da Mama/genética , Predisposição Genética para Doença , Leptina/genética , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Alelos , Biomarcadores Tumorais , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/metabolismo , Estudos de Casos e Controles , Feminino , Frequência do Gene , Interação Gene-Ambiente , Estudos de Associação Genética , Genótipo , Humanos , Mamografia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Fatores de RiscoRESUMO
BACKGROUND: Cytomegaloviruses belong to a large, ancient, genus of DNA viruses comprised of a wide array of species-specific strains that occur in diverse array of hosts. METHODS: In this study we sequenced the ~217 Kb genome of a cytomegalovirus isolated from a Mauritius cynomolgus macaque, CyCMV Mauritius, and compared it to previously sequenced cytomegaloviruses from a cynomolgus macaque of Filipino origin (CyCMV Ottawa) and two from Indian rhesus macaques (RhCMV 180.92 and RhCMV 68-1). RESULTS: Though more closely related to CyCMV Ottawa, CyCMV Mauritius is less genetically distant from both RhCMV strains than is CyCMV Ottawa. Several individual genes, including homologues of CMV genes RL11B, UL123, UL83b, UL84 and a homologue of mammalian COX-2, show a closer relationship between homologues of CyCMV Mauritius and the RhCMVs than between homologues of CyCMV Mauritius and CyCMV Ottawa. A broader phylogenetic analysis of 12 CMV strains from eight species recovers evolutionary relationships among viral strains that mirror those amongst the host species, further demonstrating co-evolution of host and virus. CONCLUSIONS: Phylogenetic analyses of rhesus and cynomolgus macaque CMV genome sequences demonstrate co-speciation of the virus and host.
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Evolução Biológica , Citomegalovirus/classificação , Genoma Viral , Macaca fascicularis/virologia , Macaca mulatta/virologia , Filogenia , Animais , Citomegalovirus/genética , Citomegalovirus/isolamento & purificação , DNA Viral/genética , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
Punicic acid (PA) is a polyunsaturated fatty acid (18:3 n-5), which is classified as a conjugated linolenic acid. PA is also referred as a "super CLnA" whose effect is even more potent than that of an ordinary CLnA. It is found mainly in the seeds of pomegranate fruit (Punica granatum) and Trichoxanthes kirilowii and some other minor sources. It possesses a wide array of biological properties including antidiabetic, antiobesity, antiproliferative, and anticarcinogenic activity against various forms of cancer. In spite of this, PA has not been explored as a nutraceutical or as an ingredient of food products which can be aimed at specific consumer target groups. This review details the various health-beneficial properties of PA and explores the possibilities of its utilization as an active ingredient in various food products.
Punicic acid, with its wide array of health-beneficial properties, needs to be utilized as a compound or as a main ingredient of pomegranate seed oil in various food formulations. This would not only add value to the waste from the pomegranate industry, but also would contribute to waste management solutions.
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Pomegranate (Punica granatum) peel possess higher antioxidant activity than the edible portion. Efforts were made to extract dry peel powder at room temperature (28-30 °C) using combination of water and ethanol (EtOH, a green combination) and standardize the factors that may affect the extraction efficiency. The storage stability of the extract has been studied for >100 days at room temperature (28-30 °C), 4, 0 and -80 °C. The extract quality was monitored by measuring the radical scavenging activity (RSA) by diphenyl picrylhydrazyl (DPPH) method, total polyphenol content and by estimating the contents of punicalagins and ellagic acid, the two major ellagitannins present in the peel. The standardized conditions for extraction were found to be; Water and EtOH in 1:1 (v/v) ratio, duration of 24-48 h, ratio of 1:10 for solid to solvent and particle size in the range of 100-400 µ. Consecutive extraction of the peel powder did neither improve the yield nor polyphenol content, hence single extraction was adopted. The extract stored at room temperature for 110 days resulted in 13.2 % loss of polyphenol content followed by 8.9, 2.8, 27.5 and 14.1 % loss in Punicalgin A, B, Ellagic acid and RSA content, respectively.
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Empty sella syndrome is a damaged pituitary gland. Either the gland has shrunk or has been crushed and flattened making it look like an empty sella on MRI scan. The reported prevalence of primary empty sella in general population is 8-35 %. The incidence is more in females, the ratio being 5:1. It is generally found in middle aged women who are obese and hypertensive.
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Varicella-zoster virus (VZV) is a member of the alphaherpesvirus family and the causative agent of chickenpox and shingles. To determine the utility of cynomolgus macaques (Macaca fascicularis) as a nonhuman primate model to evaluate VZV-based simian immunodeficiency virus/human immunodeficiency virus (SIV/HIV) vaccines, we experimentally inoculated 10 animals with the parental Oka (Oka-P) strain of VZV derived from MeWo or Telo-RF cells. VZV DNA could be detected in the lungs as late as 4 days postinfection, with replicating virus detected by shell vial culture assay in one case. Infection did not result in any overt clinical symptoms but was characterized by humoral and cell-mediated immunity in a time frame and at a magnitude similar to those observed following VZV vaccination in humans. The cell line source of VZV inoculum influenced both the magnitude and polyfunctionality of cell-mediated immunity. Animals mounted a vigorous anamnestic antibody response following a second inoculation 12 weeks later. Inoculations resulted in transient increases in CD4(+) T-cell activation and proliferation, as well as a sustained increase in CD4(+) T cells coexpressing CCR5 and α4ß7 integrin. In contrast to previous failed attempts to successfully utilize attenuated VZV-Oka as an SIV vaccine vector in rhesus macaques due to suboptimal infectivity and cellular immunogenicity, the ability to infect cynomolgus macaques with Oka-P VZV should provide a valuable tool for evaluating VZV-vectored SIV/HIV vaccines.
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Varicela/virologia , Modelos Animais de Doenças , Herpesvirus Humano 3/fisiologia , Macaca fascicularis , Animais , Anticorpos Antivirais/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologia , Linhagem Celular , Varicela/imunologia , Vetores Genéticos/genética , Vetores Genéticos/fisiologia , Herpesvirus Humano 3/genética , Herpesvirus Humano 3/imunologia , Humanos , MasculinoRESUMO
Cynomolgus macaques are widely used as an animal model in biomedical research. We have established an immortalized cynomolgus macaque fibroblast cell line (MSF-T) by transducing primary dermal fibroblasts isolated from a 13-year-old male cynomolgus macaque with a retrovirus vector expressing human telomerase reverse transcriptase (hTERT). The MSF-T cells showed increased telomerase enzyme activity and reached over 200 in vitro passages compared to the non-transduced dermal fibroblasts, which reached senescence after 43 passages. The MSF-T cell line is free of mycoplasma contamination and is permissive to the newly identified cynomolgus macaque cytomegalovirus (CyCMV). CyCMV productively infects MSF-T cells and induces down-regulation of MHC class I expression. The MSF-T cell line will be extremely useful for the propagation of CyCMV and other cynomolgus herspesviruses in host-derived fibroblast cells, allowing for the retention of host-specific viral genes. Moreover, this cell line will be beneficial for many in vitro experiments related to this animal model.
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Citomegalovirus/crescimento & desenvolvimento , Fibroblastos/virologia , Animais , Linhagem Celular , Macaca , Telomerase/genética , Telomerase/metabolismo , Transdução Genética , Cultura de Vírus/métodosRESUMO
BACKGROUND: Early childhood caries is a significant public health concern affecting about 600 million children globally. The etiology of early childhood caries can be explained as an interplay between genetic and environmental factors. Single nucleotide polymorphisms are the most common variations in the human genome. Genetic variations of immune response genes can modify the defense response of the host, and alter the susceptibility to bacterial colonization of the oral cavity and early childhood caries. The aim of this systematic review is to identify genetic variants of immune response genes associated with early childhood caries. RESULTS: A total of 7124 articles were identified by conducting an elaborate search across various electronic databases and genome-wide association studies databases. Subsequent to exclusion at various stages, fifteen articles qualified to be included into the present review. Risk of bias assessment was done with the Q-genie tool. Quantitative synthesis revealed that the odds ratio for TT and CC genotypes of rs11362 was 1.07 (0.67-1.71) and 1.16 (0.84-1.60), respectively. Gene-based analysis revealed a statistically significant association between variants of tumor necrosis factor-alpha gene and T-cell receptor alpha variable 4 locus with early childhood caries. Gene clustering showed the presence of three functional clusters. To comprehend the protein-protein interaction, the bioinformatic tool of "Search Tools for the Retrieval of Interacting Genes and Proteins" was used. Among the biological processes and the reactome pathways, complement activation through the lectin pathway showed the highest strength of association with early childhood caries. To understand the interaction and functionality of the genes, "gene function prediction using Multiple Association Network Integration Algorithm" was used, which revealed that the genes were linked by physical interaction (39.34%) and through co-expression (34.88%). CONCLUSIONS: Genotype TT of rs7217186 of arachidonate 15-lipoxygenase gene was a risk factor for early childhood caries. Multiple genetic variants of T-cell receptor alpha variable 4 locus and tumor necrosis factor-alpha gene were associated with increased susceptibility to early childhood caries. Polymorphisms of genes regulating the lectin pathway of complement activation can modify the susceptibility to early childhood caries.
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INTRODUCTION: Periapical infection of primary molars affects the development of permanent teeth (premolars). Therefore, the present study was conducted to test the null hypothesis in children aged 4-10 years with chronic apical periodontitis (CAP) of the primary molars. MATERIALS AND METHODS: A retrospective, cross-sectional study was conducted on 185 panoramic radiographs of healthy children aged 4-10 years with CAP in the primary molars. A total of 256 infected primary molars (144 teeth in females, 112 teeth in males) were analyzed, radiographically, and compared with 245 healthy primary molars on the contralateral side. Permanent successors were evaluated for follicular damage, maturation, morphology, and deviation in the eruption path. Primary molars were evaluated for root resorption. Sixteen permanent teeth on the affected side and five teeth on the control side were excluded due to abnormal development. Student's t-test and the chi-square test were used to analyze the data. RESULTS: The null hypothesis is rejected. There were significant differences in the developmental status of permanent successors on the affected side, compared to the normal side at four to seven years (p<0.05). There were no significant sex differences in the abnormalities of permanent successors on the affected side (p>0.05). As the root resorption of the primary molars increased, the follicular damage observed in the permanent successors also increased (p<0.05), which suggests that, as the infection of primary molars increases, more damage is caused to underlying permanent successors (premolars). CONCLUSION: Apical periodontitis of the primary molars retards the development of permanent successors (premolars), affects their shape, causes follicular damage, and alters the eruption path.
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Introduction The earth has experienced significant shifts in climate patterns over the past few years. The main aim of this investigation was to establish the association between the sociodemographic factors on the extent of knowledge, perspectives, and awareness of the urban population in Delhi and the phenomenon of climate change. Materials and methods This study was conducted on 1,200 individuals residing in Delhi, India, who were given a well-organized validated questionnaire to gather data. The relationship between different factors influencing awareness and climate change was evaluated using the chi-square test. Results The investigation's findings revealed that the younger generations exhibited heightened consciousness as a result of the impact of education and social media, both of which possess an exceedingly significant role in the dissemination of awareness. Additional elements that influenced the participants' awareness regarding climate change encompassed their educational attainment, profession, and financial resources, which were noticeably more advantageous for the upper and upper-middle social strata. A majority of the respondents, amounting to 65%, hailed from the middle class, with 61% of them holding degrees. The majority of the respondents were well-informed about climate change, with a predominant percentage falling within the age range of 21-40 years (77%) and over the age of 61 years (73%). Notably, 92% of the respondents belonging to the upper class exhibited awareness of climate change. About 52% of the respondents expressed a moderate level of concern towards climate change. Conclusions The analysis revealed that most individuals possessed knowledge regarding the impact of climate change on their way of life. Consequently, they acknowledged the significance of acquiring a more comprehensive understanding of climate change.
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INTRODUCTION: The consumption of smokeless tobacco (SLT) and related products has become an epidemic worldwide, especially among young people, as they come into direct contact with the tissues of the oral cavity. Therefore, the present cross-sectional study was conducted to compare the status of dentition and periodontal health of teeth associated with the unilateral SLT pouch keratosis with the unaffected contralateral side. MATERIALS AND METHODS: In this study, 96 SLT users from north Maharashtra, India, with unilateral SLT pouch keratosis were studied. Demographic data, past and present SLT use history, features of SLT pouch keratosis, modified community periodontal index, dentition status index, and loss of tooth attachment were recorded. Data were collected and subjected to statistical analysis using the unpaired t-test and chi-square test. RESULTS: The results of the present study showed a significant difference (p≤0.05) in gingival bleeding, pocket depth, and attachment loss in teeth associated with smokeless tobacco keratosis (STK) compared to teeth at the contralateral sides of the arch. The duration of tobacco use had a significant effect on the severity of loss of attachment at SLT pouch keratosis sides. There was a significant difference (p≤0.05) in the mean scores of the sound crown, carious crown, and coronal caries status between the SLT pouch keratosis side and the contralateral side. CONCLUSION: The results of the study revealed that significant gingival bleeding, gingival recession, and attachment loss in the teeth are associated with SLT pouch keratosis compared with the teeth on the contralateral side without the lesion.
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Cytomegalovirus (CMV) infection is the most common opportunistic infection in immunosuppressed individuals, such as transplant recipients or people living with HIV/AIDS, and congenital CMV is the leading viral cause of developmental disabilities in infants. Due to the highly species-specific nature of CMV, animal models that closely recapitulate human CMV (HCMV) are of growing importance for vaccine development. Here we present the genomic sequence of a novel nonhuman primate CMV from cynomolgus macaques (Macaca fascicularis; CyCMV). CyCMV (Ottawa strain) was isolated from the urine of a healthy, captive-bred, 4-year-old cynomolgus macaque of Philippine origin, and the viral genome was sequenced using next-generation Illumina sequencing to an average of 516-fold coverage. The CyCMV genome is 218,041 bp in length, with 49.5% G+C content and 84% protein-coding density. We have identified 262 putative open reading frames (ORFs) with an average coding length of 789 bp. The genomic organization of CyCMV is largely colinear with that of rhesus macaque CMV (RhCMV). Of the 262 CyCMV ORFs, 137 are homologous to HCMV genes, 243 are homologous to RhCMV 68.1, and 200 are homologous to RhCMV 180.92. CyCMV encodes four ORFs that are not present in RhCMV strain 68.1 or 180.92 but have homologies with HCMV (UL30, UL74A, UL126, and UL146). Similar to HCMV, CyCMV does not produce the RhCMV-specific viral homologue of cyclooxygenase-2. This newly characterized CMV may provide a novel model in which to study CMV biology and HCMV vaccine development.
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Citomegalovirus/genética , DNA Viral/química , DNA Viral/genética , Genoma Viral , Macaca fascicularis/virologia , Animais , Composição de Bases , Portador Sadio/veterinária , Portador Sadio/virologia , Citomegalovirus/isolamento & purificação , Infecções por Citomegalovirus/veterinária , Infecções por Citomegalovirus/virologia , Dados de Sequência Molecular , Fases de Leitura Aberta , Filipinas , Análise de Sequência de DNA , Urina/virologia , Proteínas Virais/genéticaRESUMO
Background: Fluoride (F) is an effective anticaries agent and can be delivered through various mediums at different concentrations. The ability to increase the enamel resistance to acid by decreasing solubility through the incorporation of F into the enamel apatite structure is the primary function of these agents. The efficacy of topical F can be determined by measuring the amount of F incorporated in and on human enamel. Aim: To compare the F uptake into and onto the enamel surface of two different F varnishes at different temperatures. Materials and methods: In this study, 96 teeth were divided equally and randomly (n = 48) into two experimental groups (group I and group II). Each group was further divided into four equal subgroups (n = 12); depending on the temperature (25°, 37°, 50°, and 60°C) they were subjected to Fluor-Protector® 0.7% and Embrace® 5% F varnishes were allocated to experimental groups I and II, respectively, and every sample was individually treated with the assigned F varnish. After the varnish application, two specimens from each subgroup, the group I and group II (n = 16), were mounted for hard tissue microtome sectioning for scanning electron microscope (SEM) analysis. The remaining 80 teeth underwent potassium hydroxide (KOH) soluble and KOH-insoluble F estimation. Results: Group I and group II, both, showed maximum F uptake of 2817.07 ppm and 1626.8 ppm at 37°C temperature and the lowest of 1168.9 ppm and 1068.93 ppm at 50°C, respectively. The intergroup comparison was carried out using an unpaired t-test and the intragroup comparison was done using one-way analysis of variance (ANOVA) univariate analysis.Post hoc Tukey test was performed for pairwise comparison between different temperature groups. In group I (Fluor-Protector®), the difference in F uptake was statistically significant when the temperature was increased from 25° to 37° C (mean difference = -9.90, p = 0.016). In group II (Embrace®), a statistically significant difference in F uptake was observed when the temperature was increased from 25° to 50°C (mean difference = 10.00, p = 0.003) and 25° to 60°C (mean difference = 13.38, p = 0.001), respectively. Conclusion: Fluor-Protector® varnish proved to have better F uptake in comparison to Embrace® varnish on human enamel. Topical F varnishes were most effective at 37°C, which is close to the standard human body temperature. Thus, the application of warm F varnish ensures more uptake of F in and onto the enamel surface for greater protection against dental caries. How to cite this article: Vishwakarma AP, Bondarde P, Vishwakarma P, et al. Evaluation of Fluoride Uptake of Two Fluoride Varnishes Into and onto the Enamel Surface at Different Temperatures: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(6):672-679.
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Congenital corneal anesthesia (CCA) is an extremely rare condition where the cornea is affected in isolation or as a part of congenital syndrome, or can be associated with systemic anomalies. This case series of 12 eyes provides an overview of various clinical presentations and their final treatment outcomes. The average age of presentation was 3.2 years with a female preponderance (75%). Fifty percent of the patients had bilateral involvement and 50% had corneal ulcers at presentation. Two eyes required therapeutic keratoplasty for corneal perforation. All patients had isolated CCA except for one who had an associated hereditary and sensory autonomic neuropathy.
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Anestesia , Perfuração da Córnea , Transplante de Córnea , Úlcera da Córnea , Pré-Escolar , Córnea/cirurgia , Feminino , HumanosRESUMO
Varicella-zoster virus (VZV) immediate-early 63 protein (IE63) is abundantly expressed during both acute infection in vitro and latent infection in human ganglia. Using the yeast two-hybrid system, we found that VZV IE63 interacts with human antisilencing function 1 protein (ASF1). ASF1 is a nucleosome assembly factor which is a member of the H3/H4 family of histone chaperones. IE63 coimmunoprecipitated and colocalized with ASF1 in transfected cells expressing IE63 and in VZV-infected cells. IE63 also colocalized with ASF1 in both lytic and latently VZV-infected enteric neurons. ASF1 exists in two isoforms, ASF1a and ASF1b, in mammalian cells. IE63 preferentially bound to ASF1a, and the amino-terminal 30 amino acids of ASF1a were critical for its interaction with IE63. VZV IE63 amino acids 171 to 208 and putative phosphorylation sites of IE63, both of which are critical for virus replication and latency in rodents, were important for the interaction of IE63 with ASF1. Finally, we found that IE63 increased the binding of ASF1 to histone H3.1 and H3.3, which suggests that IE63 may help to regulate levels of histones in virus-infected cells. Since ASF1 mediates eviction and deposition of histones during transcription, the interaction of VZV IE63 with ASF1 may help to regulate transcription of viral or cellular genes during lytic and/or latent infection.
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Proteínas de Ciclo Celular/metabolismo , Herpesvirus Humano 3/fisiologia , Histonas/metabolismo , Proteínas Imediatamente Precoces/metabolismo , Mapeamento de Interação de Proteínas , Proteínas do Envelope Viral/metabolismo , Latência Viral , Replicação Viral , Animais , Linhagem Celular , Células Cultivadas , Gânglios/química , Gânglios/virologia , Regulação Viral da Expressão Gênica , Cobaias , Humanos , Imunoprecipitação , Masculino , Microscopia Confocal , Chaperonas Moleculares , Neurônios/química , Neurônios/virologia , Ligação Proteica , Técnicas do Sistema de Duplo-HíbridoRESUMO
The fundamental dosimetric characteristics of commercially available metal oxide semiconductor field effect transistor (MOSFET) detectors were studied for clinical electron beam irradiations. MOSFET showed excellent linearity against doses measured using an ion chamber in the dose range of 20-630cGy. MOSFET reproducibility is better at high doses compared to low doses. The output factors measured with the MOSFET were within +/-3% when compared with those measured with a parallel plate chamber. From 4 to 12MeV, MOSFETs showed a large angular dependence in the tilt directions and less in the axial directions. MOSFETs do not show any dose-rate dependence between 100 and 600MU/min. However, MOSFETs have shown under-response when the dose per pulse of the beam is decreased. No measurable effect in MOSFET response was observed in the temperature range of 23-40 degrees C. The energy dependence of a MOSFET dosimeter was within +/-3.0% for 6-18MeV electron beams and 5.5% for 4MeV ones. This study shows that MOSFET detectors are suitable for dosimetry of electron beams in the energy range of 4-18MeV.
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Radiometria/instrumentação , Elétrons/uso terapêutico , Desenho de Equipamento , Análise de Falha de Equipamento , Radiometria/métodos , Dosagem Radioterapêutica , Reprodutibilidade dos Testes , Semicondutores , Sensibilidade e EspecificidadeRESUMO
An analysis of Ir-192 source distribution using the Monte Carlo method and radiochromic film experiments for endovascular brachytherapy is presented. Three different source possibilities, namely, mHDR Ir-192 sources with 5 mm and 2.5 mm step sizes and Ir-192 seed sources with 1 mm air gap are investigated to obtain uniform radial dose distribution throughout the treatment area. From this study, it is inferred that mHDR Ir-192 sources with 2.5 mm step size are effective for getting dose uniformity. Hence, different restenosis geometries, namely, linear, dumb bell and hairpin, are simulated with 2.5 mm step size, 15 mHDR Ir-192 sources using the Monte Carlo technique and the results are compared experimentally by using radiochromic films. The results from both methods agreed to within 7%. Further, it is also inferred that for the dosimetry of endovascular brachytherapy, the film dosimetry may be considered adequate, even if the film calibration is time consuming and requires adequate dosimetric procedures.