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1.
Nature ; 584(7820): 279-285, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32760005

RESUMO

In pathophysiology, reactive oxygen species oxidize biomolecules that contribute to disease phenotypes1. One such modification, 8-oxoguanine2 (o8G), is abundant in RNA3 but its epitranscriptional role has not been investigated for microRNAs (miRNAs). Here we specifically sequence oxidized miRNAs in a rat model of the redox-associated condition cardiac hypertrophy4. We find that position-specific o8G modifications are generated in seed regions (positions 2-8) of selective miRNAs, and function to regulate other mRNAs through o8G•A base pairing. o8G is induced predominantly at position 7 of miR-1 (7o8G-miR-1) by treatment with an adrenergic agonist. Introducing 7o8G-miR-1 or 7U-miR-1 (in which G at position 7 is substituted with U) alone is sufficient to cause cardiac hypertrophy in mice, and the mRNA targets of o8G-miR-1 function in affected phenotypes; the specific inhibition of 7o8G-miR-1 in mouse cardiomyocytes was found to attenuate cardiac hypertrophy. o8G-miR-1 is also implicated in patients with cardiomyopathy. Our findings show that the position-specific oxidation of miRNAs could serve as an epitranscriptional mechanism to coordinate pathophysiological redox-mediated gene expression.


Assuntos
Cardiomegalia/genética , Cardiomegalia/patologia , Inativação Gênica , MicroRNAs/química , MicroRNAs/metabolismo , Animais , Pareamento de Bases , Linhagem Celular , Modelos Animais de Doenças , Guanina/análogos & derivados , Guanina/análise , Guanina/química , Guanina/metabolismo , Humanos , Camundongos , MicroRNAs/genética , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Oxirredução , Ratos , Transcrição Genética/genética , Transcriptoma/genética
3.
Pediatrics ; 146(2)2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32680878

RESUMO

Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening syndrome classified into primary HLH and secondary HLH. Secondary HLH is always caused by autoimmune disease, infections, or cancer. The first-line therapy for secondary HLH is the HLH 2004 protocol, including dexamethasone, etoposide, and supportive therapy. However, up to 30% of patients, especially pediatric patients, remain unresponsive to first-line treatment, and the mortality rate reaches 50% in children with HLH. Furthermore, some children who have special conditions, such as an active virus infection, are not suitable for immunosuppressants treatment. Recently, several HLH-promoting cytokines have been identified, including interferon-γ, interleukin-2, and interleukin-6. Janus kinase 1 and 2 control the signaling of many cytokines, notably interferon-γ, interleukin-2, and interleukin-6. Janus kinase 1 and 2 inhibitors, such as ruxolitinib, have been successfully used to treat HLH in mice. Here, we report that a boy, diagnosed with HLH and high titer of hepatitis B virus-DNA copies, improved quickly, and the cytokine storm of HLH was alleviated after receiving ruxolitinib. Five days after ruxolitinib treatment, entecavir was introduced and serum titer results of hepatitis B virus-DNA returned negative. With 3 months of ruxolitinib treatment and following-up 1 year, the boy's situation maintained sustained remission. In this study, it is suggested that ruxolitinib might be a first-line drug, which could alleviate the cytokine storm of HLH. This treatment may be ushering in the age of glucocorticosteroid-free HLH treatment, which is particularly meaningful for children because it avoids the side effects of glucocorticosteroid.


Assuntos
Síndrome da Liberação de Citocina/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/etiologia , Pirazóis/uso terapêutico , Antivirais/efeitos adversos , Antivirais/uso terapêutico , Criança , Síndrome da Liberação de Citocina/etiologia , Quimioterapia Combinada , Febre/etiologia , Guanina/análogos & derivados , Guanina/uso terapêutico , Hepatite B Crônica/complicações , Hepatite B Crônica/congênito , Hepatite B Crônica/tratamento farmacológico , Humanos , Interferon-alfa/efeitos adversos , Interferon-alfa/uso terapêutico , Janus Quinases/antagonistas & inibidores , Masculino , Polietilenoglicóis/efeitos adversos , Polietilenoglicóis/uso terapêutico , Pirazóis/farmacologia , Proteínas Recombinantes/efeitos adversos , Proteínas Recombinantes/uso terapêutico , Carga Viral
4.
Mem Inst Oswaldo Cruz ; 115: e190469, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32638832

RESUMO

BACKGROUND Oxidative stress is responsible for generating DNA lesions and the 8-oxoguanine (8-oxoG) is the most commonly lesion found in DNA damage. When this base is incorporated during DNA replication, it could generate double-strand DNA breaks and cellular death. MutT enzyme hydrolyzes the 8-oxoG from the nucleotide pool, preventing its incorporation during DNA replication. OBJECTIVES To investigate the importance of 8-oxoG in Leishmania infantum and L. braziliensis, in this study we analysed the impact of heterologous expression of Escherichia coli MutT (EcMutT) enzyme in drug-resistance phenotype and defense against oxidative stress. METHODS Comparative analysis of L. braziliensis and L. infantum H2O2 tolerance and cell cycle profile were performed. Lines of L. braziliensis and L. infantum expressing EcMutT were generated and evaluated using susceptibility tests to H2O2 and SbIII, cell cycle analysis, γH2A western blotting, and BrdU native detection assay. FINDINGS Comparative analysis of tolerance to oxidative stress generated by H2O2 showed that L. infantum is more tolerant to exogenous H2O2 than L. braziliensis. In addition, cell cycle analysis showed that L. infantum, after treatment with H2O2, remains in G1 phase, returning to its normal growth rate after 72 h. In contrast, after treatment with H2O2, L. braziliensis parasites continue to move to the next stages of the cell cycle. Expression of the E. coli MutT gene in L. braziliensis and L. infantum does not interfere in parasite growth or in susceptibility to SbIII. Interestingly, we observed that L. braziliensis EcMutT-expressing clones were more tolerant to H2O2 treatment, presented lower activation of γH2A, a biomarker of genotoxic stress, and lower replication stress than its parental non-transfected parasites. In contrast, the EcMutT is not involved in protection against oxidative stress generated by H2O2 in L. infantum. MAIN CONCLUSIONS Our results showed that 8-oxoG clearance in L. braziliensis is important to avoid misincorporation during DNA replication after oxidative stress generated by H2O2.


Assuntos
Antimônio/toxicidade , Proteínas de Escherichia coli/genética , Escherichia coli , Guanina/análogos & derivados , Leishmania braziliensis/efeitos dos fármacos , Leishmania infantum/efeitos dos fármacos , Pirofosfatases , Superóxido Dismutase/metabolismo , Animais , Antiprotozoários/farmacologia , Proteínas de Escherichia coli/metabolismo , Guanina/farmacologia , Humanos , Peróxido de Hidrogênio/toxicidade , Leishmania braziliensis/enzimologia , Leishmania infantum/enzimologia , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Pirofosfatases/genética , Pirofosfatases/metabolismo , Coelhos , Ratos , Superóxido Dismutase/genética
5.
Medicine (Baltimore) ; 99(27): e21032, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32629728

RESUMO

BACKGROUND: Chronic hepatitis B is often complicated with different degrees of hepatic fibrosis, which affects the quality of life. Nucleoside analogs are recommended by almost all guidelines in the world for the treatment of chronic hepatitis B. At present, there is no specific and effective chemical and biological agents for hepatic fibrosis. In China, Chinese compound prescription combined with nucleoside analogs have been used to treat hepatic fibrosis of chronic hepatitis B patients in more and more cases, and good results have been achieved. Several Chinese compound prescriptions that have been made into proprietary Chinese medicine for the convenience of use. This article aims to systematically evaluate the efficacy and safety of Chinese medicine compounds assisting nucleoside analogs in the treatment of hepatic fibrosis in chronic hepatitis B patients. METHOD: The following databases will be searched from their inception to September 2019: PubMed, EMBASE, EBSCOhost, The Cochrane Library, China National Knowledge Infrastructure (CNKI), Chinese Biomedical literature Database (CBM), VIP Database, Wanfang Database. Languages are limited to Chinese and English. The study includes randomized controlled trials using Chinese compound prescription combined with entecavir and Chinese compound prescription combined with tenofovir disoproxil fumarate to treat hepatic fibrosis of chronic hepatitis B patients. The primary outcomes including effective rate and biochemical parameters (levels of hyaluronic acid, laminin, pre-type-III collagen and type IV collagen will be tested. Additional outcomes include liver function indexes (levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin) and levels of hepatitis B virus DNA. Stata14.0 software will be used for meta-analysis. RESULT: The efficacy and safety of Chinese compound prescriptions assisting nucleoside analogs for hepatic fibrosis of chronic hepatitis B patients will be assessed from the effective rate, biochemical parameters, liver function indexes, and levels of hepatitis B virus DNA. CONCLUSION: The conclusion of this study will be used to evaluate the efficacy and safety of Chinese compound prescriptions assisting nucleoside analogs in the treatment of hepatic fibrosis of chronic hepatitis B patients, as well as the adjuvant effectiveness of Chinese compound prescriptions in combined therapy. PROSPERO REGISTRATION NUMBER: CRD42020156859.


Assuntos
Hepatite B Crônica/tratamento farmacológico , Cirrose Hepática/tratamento farmacológico , Nucleosídeos/análogos & derivados , Antivirais/uso terapêutico , China/epidemiologia , Vírus de DNA/efeitos dos fármacos , Bases de Dados Factuais , Quimioterapia Combinada/métodos , Medicamentos de Ervas Chinesas/uso terapêutico , Feminino , Guanina/análogos & derivados , Guanina/uso terapêutico , Hepatite B Crônica/complicações , Humanos , Cirrose Hepática/etiologia , Cirrose Hepática/psicologia , Testes de Função Hepática/métodos , Masculino , Nucleosídeos/uso terapêutico , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Tenofovir/uso terapêutico
8.
Medicine (Baltimore) ; 99(22): e20330, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32481407

RESUMO

The renal protective effect of telbivudine (LdT) was verified by a previous meta-analysis. It was left unclear, however if this effect offsets the associated risk of virological breakthrough in hepatitis B e-antigen-negative (HBeAg-) patients receiving chemotherapy (C/T).Records of 260 HBeAg-, non-cirrhotic cancer patients undergoing systemic C/T with prophylactic LdT or entecavir (ETV) were retrospectively investigated. The investigation was conducted 6 months after completion of C/T, patient death from cancer, or antiviral modification. Treatment duration, outcome, change of renal function, and reason for antiviral modification were analyzed. The primary endpoint was the occurrence of virological breakthrough during prophylaxis C/T and the change in renal function.Of the 126 HBeAg- patients treated with LdT, 3 (2.38%) experienced HBV virological breakthroughs, whereas none of the patients treated with ETV (P = .07) did. The estimated glomerular filtration rate for the patients treated with LdT was essentially unaltered, decreasing only slightly from 87.5 ±â€Š23.1 to 87.3 ±â€Š21.3 ml/minute/1.73 m (P = .55), while the rate for the ETV-treated patients was significantly lowered from 95.7 ±â€Š32.2 to 85.5 ±â€Š85.7 ml/minute/1.73 m (P = .0009).The absolute risk reduction ARR is 27.8% - 21.2% = 6.6%, comparing ETV with LdT for reduction of renal function impairment and the absolute risk increase for virological breakthrough during C/T, the absolute risk increase (ARI) is 2.38% - 0% = 2.38%. The overall likelihood of being helped over being harmed was 2.77. With careful selection of patients with the criteria of HBeAg-status and non-hematologic cancer, it is feasible that telbivudine raise lower probability of virological breakthroughs during prophylaxis treatment.


Assuntos
Antineoplásicos/uso terapêutico , Antivirais/uso terapêutico , Guanina/análogos & derivados , Antígenos E da Hepatite B/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Telbivudina/uso terapêutico , Lesão Renal Aguda/induzido quimicamente , Lesão Renal Aguda/prevenção & controle , Adulto , Idoso , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Antivirais/administração & dosagem , Antivirais/efeitos adversos , Feminino , Taxa de Filtração Glomerular , Guanina/administração & dosagem , Guanina/efeitos adversos , Guanina/uso terapêutico , Humanos , Testes de Função Renal , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Telbivudina/administração & dosagem , Telbivudina/efeitos adversos
9.
Antiviral Res ; 180: 104857, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32562705

RESUMO

SARS-CoV-2, a member of the coronavirus family, is responsible for the current COVID-19 worldwide pandemic. We previously demonstrated that five nucleotide analogues inhibit the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp), including the active triphosphate forms of Sofosbuvir, Alovudine, Zidovudine, Tenofovir alafenamide and Emtricitabine. We report here the evaluation of a library of nucleoside triphosphate analogues with a variety of structural and chemical features as inhibitors of the RdRps of SARS-CoV and SARS-CoV-2. These features include modifications on the sugar (2' or 3' modifications, carbocyclic, acyclic, or dideoxynucleotides) or on the base. The goal is to identify nucleotide analogues that not only terminate RNA synthesis catalyzed by these coronavirus RdRps, but also have the potential to resist the viruses' exonuclease activity. We examined these nucleotide analogues for their ability to be incorporated by the RdRps in the polymerase reaction and to prevent further incorporation. While all 11 molecules tested displayed incorporation, 6 exhibited immediate termination of the polymerase reaction (triphosphates of Carbovir, Ganciclovir, Stavudine and Entecavir; 3'-OMe-UTP and Biotin-16-dUTP), 2 showed delayed termination (Cidofovir diphosphate and 2'-OMe-UTP), and 3 did not terminate the polymerase reaction (2'-F-dUTP, 2'-NH2-dUTP and Desthiobiotin-16-UTP). The coronaviruses possess an exonuclease that apparently requires a 2'-OH at the 3'-terminus of the growing RNA strand for proofreading. In this study, all nucleoside triphosphate analogues evaluated form Watson-Crick-like base pairs. The nucleotide analogues demonstrating termination either lack a 2'-OH, have a blocked 2'-OH, or show delayed termination. Thus, these nucleotide analogues are of interest for further investigation to evaluate whether they can evade the viral exonuclease activity. Prodrugs of five of these nucleotide analogues (Cidofovir, Abacavir, Valganciclovir/Ganciclovir, Stavudine and Entecavir) are FDA-approved medications for treatment of other viral infections, and their safety profiles are well established. After demonstrating potency in inhibiting viral replication in cell culture, candidate molecules can be rapidly evaluated as potential therapies for COVID-19.


Assuntos
Antivirais/farmacologia , Infecções por Coronavirus/virologia , Nucleotídeos/farmacologia , Pneumonia Viral/virologia , RNA Replicase/antagonistas & inibidores , Vírus da SARS/enzimologia , Síndrome Respiratória Aguda Grave/virologia , Antivirais/química , Antivirais/uso terapêutico , Betacoronavirus/enzimologia , Betacoronavirus/genética , Cidofovir/química , Cidofovir/farmacologia , Cidofovir/uso terapêutico , Infecções por Coronavirus/tratamento farmacológico , Didesoxinucleosídeos/química , Didesoxinucleosídeos/farmacologia , Didesoxinucleosídeos/uso terapêutico , Ganciclovir/química , Ganciclovir/farmacologia , Ganciclovir/uso terapêutico , Guanina/análogos & derivados , Guanina/química , Guanina/farmacologia , Guanina/uso terapêutico , Nucleotídeos/química , Nucleotídeos/uso terapêutico , Pandemias , Pneumonia Viral/tratamento farmacológico , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Pró-Fármacos/uso terapêutico , RNA Viral/antagonistas & inibidores , RNA Viral/biossíntese , Vírus da SARS/genética , Síndrome Respiratória Aguda Grave/tratamento farmacológico , Estavudina/química , Estavudina/farmacologia , Estavudina/uso terapêutico , Valganciclovir/química , Valganciclovir/farmacologia , Valganciclovir/uso terapêutico
10.
Nat Commun ; 11(1): 2484, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424276

RESUMO

DNA damage contributes to brain aging and neurodegenerative diseases. However, the factors stimulating DNA repair to stave off functional decline remain obscure. We show that HDAC1 modulates OGG1-initated 8-oxoguanine (8-oxoG) repair in the brain. HDAC1-deficient mice display age-associated DNA damage accumulation and cognitive impairment. HDAC1 stimulates OGG1, a DNA glycosylase known to remove 8-oxoG lesions that are associated with transcriptional repression. HDAC1 deficiency causes impaired OGG1 activity, 8-oxoG accumulation at the promoters of genes critical for brain function, and transcriptional repression. Moreover, we observe elevated 8-oxoG along with reduced HDAC1 activity and downregulation of a similar gene set in the 5XFAD mouse model of Alzheimer's disease. Notably, pharmacological activation of HDAC1 alleviates the deleterious effects of 8-oxoG in aged wild-type and 5XFAD mice. Our work uncovers important roles for HDAC1 in 8-oxoG repair and highlights the therapeutic potential of HDAC1 activation to counter functional decline in brain aging and neurodegeneration.


Assuntos
Envelhecimento/patologia , Doença de Alzheimer/patologia , Encéfalo/patologia , Dano ao DNA , DNA Glicosilases/metabolismo , Histona Desacetilase 1/metabolismo , Estresse Oxidativo , Acetilação , Envelhecimento/genética , Doença de Alzheimer/complicações , Doença de Alzheimer/fisiopatologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/patologia , Sequência de Bases , Benzofenonas/farmacologia , Cognição/efeitos dos fármacos , Transtornos Cognitivos/complicações , Transtornos Cognitivos/patologia , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Ontologia Genética , Guanina/análogos & derivados , Guanina/metabolismo , Memória/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Regiões Promotoras Genéticas/genética
11.
Chem Biol Interact ; 327: 109140, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32442416

RESUMO

A liquid chromatograpy-nanoelectrospray ionization-high resolution tandem mass spectrometry (LC-NSI-HRMS/MS) method was developed for quantitation of the DNA adducts 7-(2'-carboxyethyl)guanine (7-2'-CEG) and N2-(1'-carboxyethyl)guanine (N2-1'-CEG), as their methyl esters, in human leukocyte DNA from smokers and non-smokers. 7-2'-CEG has been previously identified in all human liver samples analyzed and is formed from an unknown carboxyethylating agent while N2-1'-CEG is formed from the advanced glycation endproduct methyl glyoxal. The method was applied for the analysis of these two DNA adducts in leukocyte DNA from 20 smokers and 20 non-smokers, in part to test the hypothesis that 7-2'-CEG could be formed by endogenous nitrosation, as previously observed in rats treated with nitrosodihydrouracil and nitrite. Levels of 7-2'-CEG (mean ± S.D.) were 0.6 ± 0.2 pmol/µmol dG in smokers and 0.5 ± 0.2 pmol/µmol dG in non-smokers, while those of N2-1'-CEG were 4.5 ± 1.9 pmol/µmol dG in smokers and 4.6 ± 2 pmol/µmol dG in non-smokers. These results did not support our hypothesis that endogenous nitrosation of dihydrouracil in smokers leads to higher levels of 7-2'-CEG in leukocyte DNA than in non-smokers. However the study provides the first data on levels of these DNA adducts in human leukocyte DNA, and the LC-NSI-HRMS/MS method developed for their quantitation could be important for future studies of DNA damage by methyl glyoxal.


Assuntos
Adutos de DNA/sangue , Guanina/análogos & derivados , Leucócitos/química , Adolescente , Adulto , Idoso , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , DNA/química , Feminino , Guanina/sangue , Humanos , Masculino , Pessoa de Meia-Idade , não Fumantes , Fumantes , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Adulto Jovem
13.
PLoS One ; 15(5): e0232724, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374749

RESUMO

DNA damage in the A549 human lung cancer cell line treated with cold plasma irradiation was investigated. We confirmed that cold atmospheric plasma generated reactive oxygen and nitrogen species (RONS) in a liquid, and the intracellular RONS level was increased in plasma-irradiated cells. However, a notable decrease in cell viability was not observed 24 hours after plasma irradiation. Because RONS induce oxidative damage in cells, strand breaks and chemical modification of DNA in the cancer cells were investigated. We found that 8-oxoguanine (8-oxoG) formation as well as DNA strand breaks, which have been thoroughly investigated, were induced by plasma irradiation. In addition, up-regulation of 8-oxoG repair enzyme was observed after plasma irradiation.


Assuntos
Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Quebras de DNA de Cadeia Simples/efeitos dos fármacos , DNA Glicosilases/metabolismo , Reparo do DNA , Guanina/análogos & derivados , Gases em Plasma/farmacologia , Células A549 , Sobrevivência Celular/efeitos dos fármacos , DNA/metabolismo , Guanina/biossíntese , Humanos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Regulação para Cima
14.
Am J Gastroenterol ; 115(8): 1217-1225, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32355123

RESUMO

INTRODUCTION: Chronic hepatitis B (CHB) remains a major worldwide public health concern. Besifovir dipivoxil maleate (BSV) is a new promising treatment for CHB. However, long-term efficacy and safety have not yet been evaluated. Therefore, the goal of the study is to determine the antiviral efficacy and safety of BSV treatment over a 144-week duration (BSV-BSV) in comparison with those of a sequential treatment with tenofovir disoproxil fumarate (TDF) followed by a 96-week duration BSV administration (TDF-BSV). METHODS: After 48 weeks of a double-blind comparison between BSV and TDF treatments, patients continued the open-label BSV study. We evaluated antiviral efficacy and drug safety up to 144 weeks for BSV-BSV and TDF-BSV groups. The primary endpoint was a virological response (hepatitis B virus DNA < 69 IU/mL). RESULTS: Among the 197 patients enrolled, 170 and 158 patients entered the second-year and third-year open-label phase extensional study, respectively, whereas 153 patients completed the 144-week follow-up. The virological response rate over the 144-week period was 87.7% and 92.1% in BSV-BSV and TDF-BSV groups, respectively (P = 0.36). The rates of ALT normalization and HBeAg seroconversion were similar between the groups. No drug-resistant mutations to BSV were noted. Bone mineral density and renal function were well preserved in the BSV-BSV group and were significantly improved after switching therapy in TDF-BSV patients. DISCUSSION: This extensional study of a phase 3 trial (NCT01937806) suggests that BSV treatment is efficacious and safe for long-term use in treatment-naïve and TDF-experienced patients with CHB.


Assuntos
Antivirais/uso terapêutico , Guanina/análogos & derivados , Hepatite B Crônica/tratamento farmacológico , Organofosfonatos/uso terapêutico , Adulto , Antivirais/administração & dosagem , Densidade Óssea , Método Duplo-Cego , Esquema de Medicação , Feminino , Guanina/administração & dosagem , Guanina/uso terapêutico , Vírus da Hepatite B , Hepatite B Crônica/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Organofosfonatos/administração & dosagem , República da Coreia , Tenofovir/administração & dosagem , Tenofovir/uso terapêutico , Resultado do Tratamento , Carga Viral
15.
Mutat Res ; 852: 503160, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32265045

RESUMO

Professor Barbara Tudek received the Frits Sobels Award in 2019 from the European Environmental Mutagenesis and Genomics Society (EEMGS). This article presents her outstanding character and most important lines of research. The focus of her studies covered alkylative and oxidative damage to DNA bases, in particular mutagenic and carcinogenic properties of purines with an open imidazole ring and 8-oxo-7,8-dihydroguanine (8-oxoGua). They also included analysis of mutagenic properties and pathways for the repair of DNA adducts of lipid peroxidation (LPO) products arising in large quantities during inflammation. Professor Tudek did all of this in the hope of deciphering the mechanisms of DNA damage removal, in particular by the base excision repair (BER) pathway. Some lines of research aimed at discovering factors that can modulate the activity of DNA damage repair in hope to enhance existing anti-cancer therapies. The group's ongoing research aims at deciphering the resistance mechanisms of cancer cell lines acquired following prolonged exposure to photodynamic therapy (PDT) and the possibility of re-sensitizing cells to PDT in order to increase the application of this minimally invasive therapeutic method.


Assuntos
Carcinogênese/metabolismo , Reparo do DNA , Guanina/análogos & derivados , Neoplasias/história , Fotoquimioterapia/história , Radiossensibilizantes/uso terapêutico , Animais , Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/metabolismo , Carcinogênese/genética , Carcinogênese/patologia , Linhagem Celular Tumoral , Adutos de DNA/química , Adutos de DNA/metabolismo , Dano ao DNA , Guanina/metabolismo , História do Século XX , História do Século XXI , Humanos , Peroxidação de Lipídeos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Fotoquimioterapia/métodos
16.
J Med Chem ; 63(6): 3215-3226, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32142284

RESUMO

Deoxyhypusine synthase (DHPS) utilizes spermidine and NAD as cofactors to incorporate a hypusine modification into the eukaryotic translation initiation factor 5A (eIF5A). Hypusine is essential for eIF5A activation, which, in turn, plays a key role in regulating protein translation of selected mRNA that are associated with the synthesis of oncoproteins, thereby enhancing tumor cell proliferation. Therefore, inhibition of DHPS is a promising therapeutic option for the treatment of cancer. To discover novel lead compounds that target DHPS, we conducted synthetic studies with a hit obtained via high-throughput screening. Optimization of the ring structures of the amide compound (2) led to bromobenzothiophene (11g) with potent inhibitory activity against DHPS. X-ray crystallographic analysis of 11g complexed with DHPS revealed a dramatic conformational change in DHPS, which suggests the presence of a novel allosteric site. These findings provide the basis for the development of novel therapy distinct from spermidine mimetic inhibitors.


Assuntos
Inibidores Enzimáticos/química , Indóis/química , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/antagonistas & inibidores , Tiofenos/química , Sítio Alostérico , Cristalografia por Raios X , Descoberta de Drogas , Ensaios Enzimáticos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/metabolismo , Guanina/análogos & derivados , Guanina/metabolismo , Ensaios de Triagem em Larga Escala , Humanos , Indóis/síntese química , Indóis/metabolismo , Estrutura Molecular , NAD/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/química , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Ligação Proteica , Conformação Proteica/efeitos dos fármacos , Espermidina/metabolismo , Relação Estrutura-Atividade , Tiofenos/síntese química , Tiofenos/metabolismo
17.
Int J Clin Oncol ; 25(7): 1327-1333, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32200482

RESUMO

BACKGROUND: Patients with hepatitis B virus (HBV) infection have a risk of reactivation after chemotherapy. All patients undergoing chemotherapy should be screened for HBV infection. No large-scale studies have been conducted to examine HBV screening practice in Japan. METHODS: We analyzed health insurance claims equivalent data linked with a nationwide hospital-based cancer registry. Patients diagnosed with cancer in 2014, who were aged 20 years and older and those who underwent systemic anticancer treatment in 2014-15 were included. We assessed the HBV screening rates by the HBsAg or anti-HBc tests, HBV-DNA tests, and entecavir prescriptions. Multiple logistic regression models were used to identify factors related to the receipt of screening. RESULTS: Of 177,597 patients (mean [SD] age, 65.6 [12.2] years), 82.6% and 12.9% patients had a solid tumor and hematologic malignancy, respectively. Among them, 88.1%, 6.3%, and 5.5% received cytotoxic chemotherapy, targeted therapy, and anti-CD20 antibodies, respectively. Overall, 70.6% of patients were screened. The positive predictor of HBV screening was receiving anti-CD20 antibodies [odds ratio (OR); 2.23, 95% confidence interval (CI) 2.06-2.41, p < 0.001] and negative predictors were age ≥ 85 (OR 0.76, 95% CI 0.71-0.81), age 75-84 (OR 0.77, 95% CI 0.75-0.79) and targeted therapy (OR 0.69, 95% CI 0.67-0.72). Among the screened patients, 13.2% were tested for HBV-DNA, and 1.49% were prescribed entecavir. CONCLUSIONS: The HBV screening rate in Japan is higher than in other countries. Further improvement of the HBV screening rate is needed to prevent reactivation and avoidable deaths of patients with HBV infection.


Assuntos
Vírus da Hepatite B/metabolismo , Hepatite B/diagnóstico , Neoplasias/virologia , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/uso terapêutico , Antígenos CD20/imunologia , Antineoplásicos/uso terapêutico , Feminino , Guanina/análogos & derivados , Guanina/uso terapêutico , Hepatite B/epidemiologia , Hepatite B/etiologia , Hepatite B/prevenção & controle , Anticorpos Anti-Hepatite B/sangue , Antígenos de Superfície da Hepatite B/sangue , Humanos , Japão/epidemiologia , Masculino , Programas de Rastreamento/estatística & dados numéricos , Pessoa de Meia-Idade , Neoplasias/tratamento farmacológico , Razão de Chances , Ativação Viral/efeitos dos fármacos
18.
BMC Infect Dis ; 20(1): 230, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32188424

RESUMO

BACKGROUND: Hepatitis B virus (HBV) infection is a major public health problem worldwide. More than 2 billion people have been exposed to HBV, and about 257 million individuals are chronic carriers of HBV. HBV reactivation has been increasingly reported in HBV carriers who have undergone immunosuppression or chemotherapy, resulting in mortality. Treatment of hypothalamic/pituitary tumors in HBV carriers requires extensive care to avoid HBV reactivation as steroid therapy is required after surgery for hypothalamic/pituitary tumors. CASE PRESENTATION: This retrospective review identified 5 patients, who were HBV carriers positive for hepatitis B surface antigen among 1352 patients with surgically treated hypothalamic/pituitary tumor in Kohnan Hospital between February 2007 and April 2017. Transsphenoidal surgery was performed with particular attention to prevent damage to the pituitary gland, with delicate manipulation to minimize postoperative steroid coverage. All patients received nucleot(s)ide analogue to control HBV-DNA levels before the surgery. As a result, all patients had a good clinical course. Blood examinations found a transient increase of liver enzymes and HBV-DNA levels in all patients, which started to decrease within 2 weeks after surgery. No specific treatment other than nucleot(s)ide analogues was needed to maintain liver function, and all patients returned to their previous activities including reinstatement. CONCLUSION: Initiation of nucleot(s)ide analogues administration prior to the surgery for hypothalamic/pituitary tumors can be an effective strategy for preventing reactivation in HBV carriers. Appropriate screening of the patient's HBV phase, optimal timing of nucleot(s)ide analogues -administration, and administration period of nucleot(s)ide analogues need to be established.


Assuntos
Antivirais/uso terapêutico , Hepatite B/tratamento farmacológico , Neoplasias Hipotalâmicas/cirurgia , Neoplasias Hipofisárias/cirurgia , Idoso , DNA Viral/sangue , Feminino , Guanina/análogos & derivados , Guanina/uso terapêutico , Hepatite B/virologia , Antígenos de Superfície da Hepatite B/sangue , Vírus da Hepatite B/patogenicidade , Vírus da Hepatite B/fisiologia , Humanos , Neoplasias Hipotalâmicas/virologia , Imunossupressão , Lamivudina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Neoplasias Hipofisárias/virologia , Estudos Retrospectivos , Esteroides/uso terapêutico , Ativação Viral/efeitos dos fármacos
19.
Phys Chem Chem Phys ; 22(14): 7381-7391, 2020 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-32211689

RESUMO

The thienoguanine nucleobase (thGb) is an isomorphic fluorescent analogue of guanine. In aqueous buffer at neutral pH, thGb exists as a mixture of two ground-state H1 and H3 keto-amino tautomers with distinct absorption and emission spectra and high quantum yield. In this work, we performed the first systematic photophysical characterization of thGb as a function of pH (2 to 12). Steady-state and time-resolved fluorescence spectroscopies, supplemented with theoretical calculations, enabled us to identify three additional thGb forms, resulting from pH-dependent ground-state and excited-state reactions. Moreover, a thorough analysis allowed us to retrieve their individual absorption and emission spectra as well as the equilibrium constants which govern their interconversion. From these data, the complete photoluminescence pathway of thGb in aqueous solution and its dependence as a function of pH was deduced. As the identified forms differ by their spectra and fluorescence lifetime, thGb could be used as a probe for sensing local pH changes under acidic conditions.


Assuntos
Corantes Fluorescentes/química , Guanina/análogos & derivados , Guanina/química , Concentração de Íons de Hidrogênio , Luminescência , Espectrometria de Fluorescência , Água/química
20.
Mikrobiyol Bul ; 54(1): 95-109, 2020 Jan.
Artigo em Turco | MEDLINE | ID: mdl-32050881

RESUMO

Chronic hepatitis B (CHB) is an important public health problem in the world and Turkey. The aim of this study was to evaluate the histological, virological, serological and biochemical response rates in CHB patients receiving tenofovir or entecavir therapy. Control liver biopsies were performed on patients who received tenofovir or entecavir therapy for one year or longer. Histopathological grading was scored according to the modified Knodell system. Eighty-seven CHB patients were included in this study, 56 patients were receiving tenofovir and 31 patients were receiving entecavir therapy. Patients in two treatment groups were similar in terms of baseline parameters (p> 0.05). At the end of the treatment, there was a significant decrease in mean values of HBV DNA, alanine aminotransferase and necroinflammatory scores for both groups (p<0.001); however, no statistically significant change was observed in fibrosis scores (p> 0.05). Histological responses were obtained 66.1% from the tenofovir group and 54.8% from the entecavir group. Treatment with tenofovir and entecavir resulted with improvement in Ishak fibrosis scores in 12.5% and 12.9% of the patients, respectively. For 14.3% of the tenofovir-treated patients and for 22.6% of the entecavir-treated patients, the Ishak fibrosis scores worsened. Baseline intermediate/ advanced fibrosis stage (Ishak fibrosis score: 3-6) was found as independent determinant factor on histological response and improvement of fibrosis score (OR= 3.99, p= 0.01; OR= 31.67, p= 0.002; respectively) and treatment duration longer than five years is an independent determinant for improvement of necroinflammatory score (OR= 5.79, p= 0.02). There was no significant difference in the virological, serological, biochemical and, histological responses and improvement of necroinflammatory and fibrosis scores between tenofovir and entecavir groups (p> 0.05). Similar histological, virological, serological and biochemical responses were obtained in patients with CHB receving tenofovir and entecavir treatments. Further studies involving a large number of patients receiving long-term therapy should be done to understand the effects of antiviral treatments on healing of liver histology.


Assuntos
Antivirais , Guanina/análogos & derivados , Hepatite B Crônica , Tenofovir , Antivirais/uso terapêutico , Guanina/uso terapêutico , Vírus da Hepatite B , Hepatite B Crônica/tratamento farmacológico , Humanos , Fígado/patologia , Estudos Retrospectivos , Tenofovir/uso terapêutico , Resultado do Tratamento , Turquia
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