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1.
Iran Endod J ; 19(1): 39-45, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38223837

RESUMO

Introduction: Mechanical root canal preparations and irrigation solutions are essential for reducing microbial counts in the root canal system. However, these methods do not completely eliminate microorganisms. Intracanal medicaments are used to further decrease microbial counts. This study aims to assess the cytotoxicity of various intracanal medicaments. Materials and methods: In this in vitro study, murine fibroblast cell lines (L929) were cultured in a controlled environment. The MTT assay was employed to evaluate the cytotoxicity of different medicament combinations, including calcium hydroxide and triamcinolone (D1), niosomal doxycycline and triamcinolone (D2), calcium hydroxide (D3), and a combination of doxycycline and triamcinolone (D4). Statistical analysis was performed using ANOVA and Dunnett's test. Results: The results indicated that D1 and D2 had lower cytotoxicity, while D4 exhibited the highest cytotoxicity. D1 was found to be non-cytotoxic up to a concentration of 500 µg/mL over a period of 72 hours. D2 and D3 showed similar effects up to concentrations of 250 µg/mL and 100 µg/mL, respectively, for 72 hours. In contrast, D4 exhibited cytotoxicity at concentrations above 75 µg/mL at 72 hours. Conclusion: This study suggests that encapsulating doxycycline in niosomal structures (D2) reduces cytotoxicity in murine fibroblast cell lines (L929) for at least 24 and 48 hours. These findings offer promising implications for the development of endodontic medicaments with improved biocompatibility.

2.
BMC Res Notes ; 16(1): 344, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37993939

RESUMO

BACKGROUND: The proper function of Pattern Recognition Receptors (PRRs) as a part of the host immune system can eliminate numerous pathogens from the body. However, some viruses can manipulate PRRs to escape the innate immune system. As there is controversy in the activation of PRRs in patients infected with HCV, we decided to evaluate the gene expression changes of PRRs in HCV cases compared to the healthy control. METHODS: In this study, the relative expression of Toll-like receptor 7, RIG-I, and MAD-5 in peripheral mononuclear blood cells of twenty HCV patients and twenty healthy controls of the same gender and age were analyzed by quantitative Real-time PCR. RESULTS: Our results showed that the expression of RIG-I and MAD-5 significantly increased in HCV-infected samples compared to the controls (P value:0.01; P value:0.05), while the expression of TLR7 was similar between the case and the control group (P value:0.1). CONCLUSION: It seems in suppressing HCV, RIG-I and MAD-5 receptors are likely to be more activated than TRL7 in HCV patients. The lack of TLR7 gene expression might reflect the defect of the host in the stimulation of the innate immune system through the TLR7 pathway.


Assuntos
Hepatite C , Receptor 7 Toll-Like , Humanos , Receptor 7 Toll-Like/genética , Leucócitos Mononucleares , Hepatite C/genética , Hepacivirus/genética , Expressão Gênica
3.
Iran Biomed J ; 25(3): 193-201, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33653023

RESUMO

Background: There is limited information on the three-dimensional (3D) prediction and modeling of the colistin resistance-associated proteins PmrA/B TCS in Acinetobacter baumannii. We aimed to evaluate the stereochemical structure and domain characterization of phosphotransferase membrane receptor A/B (PmrA/B) in an A. baumannii isolate resistant to high-level colistin, using bioinformatics tools. Methods: The species of the isolate and its susceptibility to colistin were confirmed by PCR-sequencing and minimum inhibitory concentration assay, respectively. For 3D prediction of the PmrA/B, we used 16 template models with the highest quality (e-value <1 × 10−50). Results: Prediction of the PmrA structure revealed a monomeric non-redundant protein consisting of 28 α-helices and 22 ß-sheets. The PmrA DNA-binding motif displayed three antiparallel α-helices, followed by three ß-sheets, and was bond to the major groove of DNA by intermolecular van der Waals bonds through amino acids Lys, Asp, His, and Arg, respectively. Superimposition of the deduced PmrA 3D structure with the closely related PmrA protein model (GenBank no. WP_071210493.1) revealed no distortion in conformation, due to Glu→Lys substitution at position 218. Similarly, the PmrB protein structure displayed 24 α-helices and 13 ß-sheets. In our case, His251 acted as a phosphate receptor in the HisKA domain. The amino acid substitutions were mainly observed at the putative N-terminus region of the protein. Furthermore, two substitutions (Lys21→Ser and Ser28→Arg) in the transmembrane domain were detected. Conclusion: The DNA-binding motif of PmrA is highly conserved, though the N-terminal fragment of PmrB showed a high rate of base substitutions. This research provides valuable insights into the mechanism of colistin resistance in A. baumannii.


Assuntos
Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/fisiologia , Proteínas de Bactérias/metabolismo , Colistina/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Acinetobacter baumannii/efeitos dos fármacos , Sequência de Aminoácidos , Proteínas de Bactérias/química , DNA Bacteriano/metabolismo , Modelos Moleculares , Ligação Proteica , Domínios Proteicos
4.
Iran J Pathol ; 13(1): 54-62, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29731796

RESUMO

BACKGROUND AND OBJECTIVE: Millions of people in developing countries lose their lives due to acute respiratory infections, such as Influenza A & B and Adeno viruses. Given the importance of rapid identification of the virus, in this study the researchers attempted to design a method that enables detection of influenza A, B, and adenoviruses, quickly and simultaneously. The Multiplex RT PCR method was the preferred method for the detection of influenza A, B, and adenoviruses in clinical specimens because it is rapid, sensitive, specific, and more cost-effective than alternative methods. METHODS: After collecting samples from patients with respiratory disease, virus genome was extracted, then Monoplex PCR was used on positive samples and Multiplex RT-PCR on clinical specimens. Finally, by comparing the bands of these samples, the type of virus in the clinical samples was determined. RESULTS: Performing Multiplex RT-PCR on 50 samples of respiratory tract led to following results; flu A: 12.5%, fluB: 50%, adeno: 27.5%, negative: 7.5%, and 2.5% contamination. CONCLUSION: Reverse transcription-multiplex Polymerase Chain Reaction (PCR) technique, a rapid diagnostic tool, has potential for high-throughput testing. This method has a significant advantage, which provides simultaneous amplification of numerous viruses in a single reaction. This study concentrates on multiplex molecular technologies and their clinical application for the detection and quantification of respiratory pathogens. The improvement in diagnostic testing for viral respiratory pathogens effects patient management, and leads to more cost-effective delivery of care. It limits unnecessary antibiotic use and improves clinical management by use of suitable treatment.

5.
Jundishapur J Microbiol ; 8(4): e17157, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26034544

RESUMO

BACKGROUND: Gradual development of a useful vaccine can be the main point in the control and eradication of Hepatitis C virus (HCV) infection. Hepatitis C Virus envelope glycoproteins are considered as the main HCV vaccine candidate. OBJECTIVES: In this study, the Pichia pastoris expression system was used to express a recombinant HCV CoreE1E2 protein, which consists of Core (269 nt-841nt) E1 (842 nt-1417nt) and E2 (1418 nt-2506nt). MATERIALS AND METHODS: By a codon optimization technique based on the P. pastoris expression system, we could increase the rate of recombinant proteins. Moreover, the purified protein can efficiently induce anti-CoreE1E2 antibodies in rabbits, and also by developing a homemade Enzyme-Linked ELISA kit we can detect antibody of HCV Iranian patients with genotype 1a. RESULTS: In our study, the virus-like particle of rCoreE1E2 with 70 nm size, was shown by Electron microscopy and proved the self-assembly in vitro in a yeast expression system. CONCLUSIONS: These findings of the present study indicate that the recombinant CoreE1E2 glycoprotein is effective in inducing neutralizing antibodies, and is an influential HCV vaccine candidate.

6.
Asian Pac J Cancer Prev ; 16(5): 1919-24, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25773845

RESUMO

Polymorphisms in the region of the interleukin IL-28 gene on chromosome 19 have been related with clearance of hepatitis C virus (HCV), a major human pathogen responsible for chronic hepatitis, cirrhosis and hepatocellular carcinoma. About 3% of the world's population is infected with HCV. The long-term response to therapy is influenced by many host and viral factors, and recent evidence has indicated that some host genetic polymorphisms related to IL-28 are the most powerful predictors of virological response in patients with HCV. This study assessed frequency of the IL-28 polymorphism (rs8099917) in 50 patients (39 men and 11 women ) with chronic hepatitis C using ZNA probe real time PCR new method . All patients were tested for genotype of HCV and the HCV viral load. In parallel, the levels of SGOT, SGPT and ALK enzymes were assessed. Treatment using Peg-interferon alpha with ribavirin was conducted for patients and subsequently samples were collected to detect any change in viral load or liver enzyme rates. The overall frequency of the TT allele is 74%, TG allele 20% and GG allele 6% and the percent of patients who had T allele was 84%. Clear reduction in viral load and liver enzymes was reported in patients with the T allele. Especially for genotype 1 which is relatively resistant to treatment, these alleles may have a role in this decline. In conclusion, we showed that IL-28 polymorphism rs8099917 strongly predicts virological response in HCV infection and that real-time PCR with Zip nucleic acid probes is a sensitive, specific and rapid detection method for detection of SNPs which will be essential for monitoring patients undergoing antiviral therapy.


Assuntos
Frequência do Gene , Hepatite C Crônica/genética , Interleucinas/genética , Adulto , Alanina Transaminase/sangue , Quinase do Linfoma Anaplásico , Anticorpos Antivirais/sangue , Antivirais/uso terapêutico , Aspartato Aminotransferases/sangue , Quimioterapia Combinada , Feminino , Hepacivirus/genética , Hepacivirus/imunologia , Antígenos de Superfície da Hepatite B/sangue , Antígenos E da Hepatite B/sangue , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/virologia , Humanos , Interferon-alfa/uso terapêutico , Irã (Geográfico) , Masculino , Pessoa de Meia-Idade , Sondas de Ácido Nucleico , Polietilenoglicóis/uso terapêutico , Polimorfismo de Nucleotídeo Único/genética , Reação em Cadeia da Polimerase em Tempo Real , Receptores Proteína Tirosina Quinases/sangue , Proteínas Recombinantes/uso terapêutico , Estudos Retrospectivos , Ribavirina/uso terapêutico , Carga Viral/efeitos dos fármacos
7.
Jundishapur J Microbiol ; 8(1): e14551, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25789128

RESUMO

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is one of the most important causes of disability and mortality in the world. Although cigarette smoking and environmental pollutants have been recognized as the major causes of COPD, the role of infection in the pathogenesis and progression of COPD has also been reported. OBJECTIVES: The aim of the present study was to find the relationship between Helicobacter Pylori infection and COPD through anti H. pylori IgG serology, real time PCR of bronchoalveolar lavage and trans bronchial biopsy urease tests. PATIENTS AND METHODS: This descriptive cross-sectional study was carried out on 60 adults with COPD. After obtaining the patient's history, physical examination, spirometry and confirmation of COPD diagnosis by pulmonologist, subjects were selected through convenience sampling. In order to determine the severity and prognosis of disease, the global initiative for chronic obstructive lung disease (GOLD) criteria and BODE index were used. Subjects underwent bronchoscopy for obtaining bronchoalveolar lavage (BAL) samples and biopsy was performed. Biopsy and BAL samples were investigated respectively by urease test and real time PCR. Moreover, patients' serum samples were serologically studied for detection of anti H. pylori IgG. RESULTS: Mean age of the participants was 60.65 ± 9.15 years, and 25% were female and 75% were male. The prevalence rate of H. pylori in COPD patients was 10% according to real time PCR, 88.3% according to the serology test and 0% based on the urease test. According to the results of PCR and considering the severity of disease based on the GOLD criteria, from those with a positive PCR, one patient (16.6%) had very severe obstruction, three (50%) had severe obstruction and two patients (33.3%) had moderate obstruction. The relationship between H. pylori presence (based on PCR) and disease severity and prognosis was not statistically significant. CONCLUSIONS: These findings can justify the hypothesis of direct injury and chronic inflammation via inhalation and aspiration resulting in H. pylori colonization. In fact, it is thought that H. Pylori infection, beside the host genetic vulnerability and other environmental risk factors might make the patient susceptible to COPD or lead to COPD worsening. Although we found H. pylori infection in some patients with COPD, the results of this study, could not explain the pathogenic mechanisms of COPD.

8.
Asian Pac J Cancer Prev ; 16(5): 1873-80, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25773839

RESUMO

BACKGROUND: A recent genome-wide association study (GWAS) on patients with chronic hepatitis C (CHC) treated with peginterferon and ribavirin (pegIFN-α/RBV) identified a single nucleotide polymorphism (SNP) on chromosome 19 (rs12979860) which was strongly associated with a sustained virological response (SVR). The aim of this study was twofold: to study the relationship between IL28B rs12979860 and sustained virological response (SVR) to pegIFN-α/RVB therapy among CHC patients and to detect the rs12979860 polymorphism by high resolution melting curve (HRM) assay as a simple, fast, sensitive, and inexpensive method. MATERIALS AND METHODS: The study examined outcomes in 100 patients with chronic hepatitis C in 2 provinces of Iran from December 2011 to June 2013. Two methods were applied to detect IL28B polymorphisms: PCR-sequencing as a gold standard method and HRM as a simple, fast, sensitive, and inexpensive method. RESULTS: The frequencies of IL28B rs12979860 CC, CT, and TT alleles in chronic hepatitis C genotype 1a patients were 10% (10/100), 35% (35/100), and 6% (6/100) and in genotype 3a were 13% (13/100), 31% (31/100), and 5% (5/100), respectively. In genotype 3a infected patients, rs12979860 (CC and CT alleles) and in genotype 1a infected patients (CC allele) were significantly associated with a sustained virological response (SVR). The SVR rates for CC, CT and TT (IL28B rs12979860) were 18%, 34% and 4%, respectively. Multiple logistic regression analysis identified two independent factors that were significantly associated with SVR: IL-28B genotype (rs 12979860 CC vs TT and CT; odds ratio [ORs], 7.86 and 4.084, respectively), and HCV subtype 1a (OR, 7.46). In the present study, an association between SVR rates and IL28B polymorphisms was observed. CONCLUSIONS: The HRM assay described herein is rapid, inexpensive, sensitive and accurate for detecting rs12979860 alleles in CHC patients. This method can be readily adopted by any molecular diagnostic laboratory with HRM capability and will be clinically beneficial in predicting treatment response in HCV genotype 1 and 3 infected patients. In addition, it was demonstrated that CC and CT alleles in HCV-3a and the CC allele in HCV-1a were significantly associated with response to pegIFN-α/RBV treatment. The present results may help identify subjects for whom the therapy might be successful.


Assuntos
Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/genética , Interferon-alfa/uso terapêutico , Interleucinas/genética , Polietilenoglicóis/uso terapêutico , Ribavirina/uso terapêutico , Adulto , Alelos , Antivirais/uso terapêutico , Sequência de Bases , Quimioterapia Combinada , Feminino , Estudo de Associação Genômica Ampla , Hepacivirus/efeitos dos fármacos , Humanos , Interferons , Irã (Geográfico) , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Proteínas Recombinantes/uso terapêutico , Análise de Sequência de DNA , Resultado do Tratamento
9.
Asian Pac J Cancer Prev ; 14(9): 5287-91, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24175815

RESUMO

The human papilloma virus (HPV) causes skin and mucous membrane infections. It crosses from one person to another by skin-to-skin contact, such as sexual contact. There are more than 100 types of HPV that can influence different parts of the body. Some types of HPV can cause cancer (such as cervical or anal cancer) and others can cause warts (such as genital or plantar warts). HPV infection is one of the most common sexually transmitted infections (STIs) in Iran and around the world. Considerable molecular evidence suggests a role for human papilloma virus (HPV) in the pathogenesis of carcinoma. Epidemiological studies on human papilloma viruses (HPVs) infections in general population are critical for the performing of health policy guidelines for developing the strategies to hinder the primary and secondary different cancer. In different parts of Iran, there is a lack of population-based studies to determine the prevalence of HPV in the general population. The aim of this population-based study was therefore to report the prevalence ratse of HPV types among Iranian patients. To study the risk of human papilloma virus (HPV) infection, we managed a retrospective study in Kerman province, southeast of Iran. For this purpose, 410 patients tested for the presence of HPV DNA using PCR and INNo- Lipa assays. HPV DNA was detected in 108 out of 410 patients (26.34%), while it was not detected in any of the control group samples. Patients included 23 (21.1%) males and 86 (78.8%) females. HPV type 6 was the most common (49%) followed by HPV type 16 (10.1%), and also HPV type11 (9.2%). The prevalence of HPV in Iran is comparable to those reported in other regions of the world. In a similar manner, it seems that HPV types 6, 16 and11 are the most common types in Kerman. Additional studies on larger group of patients, particularly in those with pre-invasive forms of disease, are needed to explain the roles of different HPV types in this location of Iran.


Assuntos
Técnicas de Diagnóstico Molecular/métodos , Papillomaviridae/classificação , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Infecções Tumorais por Vírus/epidemiologia , Infecções Tumorais por Vírus/virologia , Adolescente , Adulto , Criança , Pré-Escolar , DNA Viral/genética , Feminino , Genótipo , Humanos , Lactente , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Papillomaviridae/genética , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/genética , Reação em Cadeia da Polimerase , Estudos Retrospectivos , Fatores de Risco , Infecções Tumorais por Vírus/genética , Adulto Jovem
10.
Asian Pac J Cancer Prev ; 14(12): 7045-56, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24460249

RESUMO

Since the first report of RNA interference (RNAi) less than a decade ago, this type of molecular intervention has been introduced to repress gene expression in vitro and also for in vivo studies in mammals. Understanding the mechanisms of action of synthetic small interfering RNAs (siRNAs) underlies use as therapeutic agents in the areas of cancer and viral infection. Recent studies have also promoted different theories about cell-specific targeting of siRNAs. Design and delivery strategies for successful treatment of human diseases are becomingmore established and relationships between miRNA and RNAi pathways have been revealed as virus-host cell interactions. Although both are well conserved in plants, invertebrates and mammals, there is also variabilityand a more complete understanding of differences will be needed for optimal application. RNA interference (RNAi) is rapid, cheap and selective in complex biological systems and has created new insight sin fields of cancer research, genetic disorders, virology and drug design. Our knowledge about the role of miRNAs and siRNAs pathways in virus-host cell interactions in virus infected cells is incomplete. There are different viral diseases but few antiviral drugs are available. For example, acyclovir for herpes viruses, alpha-interferon for hepatitis C and B viruses and anti-retroviral for HIV are accessible. Also cancer is obviously an important target for siRNA-based therapies, but the main problem in cancer therapy is targeting metastatic cells which spread from the original tumor. There are also other possible reservations and problems that might delay or even hinder siRNA-based therapies for the treatment of certain conditions; however, this remains the most promising approach for a wide range of diseases. Clearly, more studies must be done to allow efficient delivery and better understanding of unwanted side effects of siRNA-based therapies. In this review miRNA and RNAi biology, experimental design, anti-viral and anti-cancer effects are discussed.


Assuntos
MicroRNAs/genética , Neoplasias/terapia , Interferência de RNA , RNA Interferente Pequeno/genética , Viroses/terapia , Animais , Humanos , Neoplasias/genética , Viroses/genética
11.
Asian Pac J Cancer Prev ; 13(11): 5463-7, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23317201

RESUMO

Hepatitis B virus (HBV) infection is contagious with transmissiobn vertically or horizontally by blood products and body secretions. Over 50% of Iranian carriers contracted the infection prenatally, making this the most likely route of transmission of HBV in Iran. To evaluate the resistance to adefovir (ADV) therapy in patients with chronic hepatitis B infection, a study was conducted on 70 patients (63 males and 7 females), who had received in first line lamivudine and second line adefovir. All were tested for the presence of hepatitis B surface antigen (HBsAg), hepatitis B envelope antigen (HBeAg), serum alanine amino transferase (ALT) level and HBV DNA load before and after treatment with ADV. In all samples, resistance to lamivudine and ADV was tested with real time PCR. Among seventy patients with chronic hepatitis B infection, 18 (25.7%) were resistant to LAM and 8 (11.4%) were resistant to ADV. Only one patient was negative for the presence of HBS-Ag (5.6%) and two were negative for HBe-Ag (11.1%). In this study we used a new method (ALLGIO probe assay) that has high sensitivity in detection of adefovir resistance mutants, which we recommend to other researchers. Mutant strains of the YMDD motif of HBV polymerase can be found in some patients under treatment with lamivudine and ADV. ADV has been demonstrated to be efficient in patients with lamivudine resistant HBV.


Assuntos
Adenina/análogos & derivados , Antivirais/farmacologia , DNA Viral/análise , Farmacorresistência Viral/genética , Vírus da Hepatite B/genética , Hepatite B Crônica/tratamento farmacológico , Sondas de Ácido Nucleico , Organofosfonatos/farmacologia , Adenina/farmacologia , Adulto , Idoso , Bioensaio , DNA Viral/genética , Feminino , Hepatite B Crônica/genética , Hepatite B Crônica/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Estudos Retrospectivos
12.
Asian Pac J Cancer Prev ; 13(8): 3657-61, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23098450

RESUMO

HBV infection is contagious and may be transmitted vertically or horizontally by blood products and body secretions. Over 50% of Iranian carriers have contracted the infection prenatally, making this the most likely route of transmission of HBV in Iran. This study assesses the resistance to Lamivudine in patients with chronic hepatitis B infection using a new ZNA probe Real Time PCR method. To evaluate the effectiveness of Lamivudine therapy for chronic hepatitis B infection, a study was conducted on 70 patients (63 men and 7 women), who had received the drug first line. All patients were tested for the presence of HBsAg and HBeAg, the serum ALT level and the HBV DNA load before and after treatment. In all samples resistance to Lamivudine was tested with the ZNA Probe. Our results showed that ZNA Probe Real Time PCR method could detect wild type,YMDD, and its mutants, tyrosine-isoleucine-aspartate-aspartate and tyrosine-valine-aspartate-Aspartate. Among an estimated seventy patients with chronic hepatitis B infection, 18 (25.7%) were resistant to lamivudine. Only one patient was negative for presence of HBS-Ag (5.6%) and two patients were negative for HBe-Ag (11.1%). Real-time PCR with Zip nucleic acid probes is a sensitive, specific and rapid detection method for mutations in the YMDD motif, which will be essential for monitoring patients undergoing Lamivudine antiviral therapy.


Assuntos
Farmacorresistência Viral/genética , Vírus da Hepatite B/genética , Hepatite B Crônica/tratamento farmacológico , Lamivudina/uso terapêutico , Inibidores da Transcriptase Reversa/uso terapêutico , Adulto , Idoso , DNA Viral/genética , Feminino , Genótipo , Antígenos E da Hepatite B/genética , Hepatite B Crônica/genética , Hepatite B Crônica/virologia , Humanos , Irã (Geográfico) , Masculino , Pessoa de Meia-Idade , Mutação/genética , Sondas de Ácido Nucleico , Reação em Cadeia da Polimerase , Estudos Retrospectivos
13.
Asian Pac J Cancer Prev ; 13(12): 5931-49, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23464383

RESUMO

BACKGROUND: Hepatitis C virus (HCV) causes acute and chronic human hepatitis infection and as such is an important global health problem. The virus was discovered in the USA in 1989 and it is now known that three to four million people are infected every year, WHO estimating that 3 percent of the 7 billion people worldwide being chronically infected. Humans are the natural hosts of HCV and this virus can eventually lead to permanent liver damage and carcinoma. HCV is a member of the Flaviviridae family and Hepacivirus genus. The diameter of the virus is about 50-60 nm and the virion contains a single-stranded positive RNA approximately 10,000 nucleotides in length and consisting of one ORF which is encapsulated by an external lipid envelope and icosahedral capsid. HCV is a heterogeneous virus, classified into 6 genotypes and more than 50 subtypes. Because of the genome variability, nucleotide sequences of genotypes differ by approximately 31-34%, and by 20-23% among subtypes. Quasi-species of mixed virus populations provide a survival advantage for the virus to create multiple variant genomes and a high rate of generation of variants to allow rapid selection of mutants for new environmental conditions. Direct contact with infected blood and blood products, sexual relationships and availability of injectable drugs have had remarkable effects on HCV epidemiology. Hundreds of thousands of people die each year from hepatitis and liver cancer caused by HCV virus infection. Approximately 80% of patients with acute hepatitis C progress into a chronic disease state leading to serious hepatic disorders, 10-20% of which develop chronic liver cirrhosis and hepatocellular carcinoma. The incubation period of HCV is 6-8 weeks and the infection is often asymptomatic so it is very hard to detect at early stages, making early treatment very difficult. Therefore, hepatitis C is called a "silent disease". Neutralizing antibodies are produced against several HCV proteins during infection but the virus mutates to escape from antibodies. Some patients with chronic hepatitis C may have some symptoms such as fatigue, muscle aches, nausea and pain. Autoimmune and immunecomplex-mediated diseases have also been reported with chronic HCV infection.


Assuntos
Hepacivirus , Hepatite C , Carcinoma Hepatocelular , Hepacivirus/genética , Hepatite C Crônica/imunologia , Humanos , Neoplasias Hepáticas , Vacinas/uso terapêutico
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