RESUMO
Hepatitis C virus (HCV) is a major cause of chronic hepatitis, cirrhosis, and liver cancer occurring in up to 3% of the world's population. Parenteral exposure to HCV is the major mode of transmission of infection. Once established, infection will persist in up to 85% of individuals with only a minority of patients clearing viremia. Egypt has possibly the highest HCV prevalence in the world where 10-20% of the general population are infected with HCV. Endemic HCV appears to be concentrated in the tropics and sub-tropics where there are higher biting rates from insects. The question as to whether a bridge vector transmission is possible, via arthropods, both between humans and/or from an animal reservoir to humans is explored. Mechanical transmission, as opposed to biological transmission, is considered. Mechanical transmission can be an efficient way of transmitting an infection, as effective as biological transmission. Probability of transmission can increase as to the immediate circumstances and conditions at the time. Several factors may enhance mechanical transmission, including high levels of microbes in the vector, frequent biting, the close proximity, and contact between vectors and recipients as well as high density of insects. HCV has been isolated from bodies or heads of mosquitoes collected from the houses of HCV-infected individuals. The possibility of enzootic cycles of HCV tangential transmission via bridging vectors, such as, arthropods needs to be further investigated and possible animal reservoirs, including domestic rural epizootic cycles for HCV infection, requires further research with particular initial emphasis on equine infections. J. Med. Virol. 89:187-194, 2017. © 2016 Wiley Periodicals, Inc.
Assuntos
Culicidae/virologia , Transmissão de Doença Infecciosa , Hepacivirus/isolamento & purificação , Hepatite C/transmissão , Mosquitos Vetores/virologia , Animais , HumanosRESUMO
HCV is a major cause of liver disease worldwide. IL-12 plays an essential role in the balance of T helper 1 (Th1) differentiation versus a T helper 2 (Th2) driven response from its naïve precursor. Linkage disequilibrium measures the degree to which alleles at two loci are associated and the non-random associations between alleles at two loci. Haplotypes of the three IL-12B loci studied were determined in the patient cases and the normal healthy control subjects. The frequency of the 12 possible IL-12B haplotypes on the 3 loci was determined in subjects heterozygous at only one of the loci within the studied haplotype. Haplotype frequencies were compared between the patient groups and controls (n = 49) to determine if any preferential combination of markers occurred using chi-squared and applying the Bonferroni correction. 45 HCV RNA negative patients; 88 HCV RNA positive patients; and 15 uninfected cases at high risk of HCV infection (EU) were studied. The haplotype "C" SNP of the 3'UTR with the "E" 4 bp deletion of the intron 4 region was in linkage disequilibrium (χ(2) = 45.15, P < 0.001, 95% CL). The haplotype analysis of the insertion allele of the promoter with the deletion allele of the intron 4("E") IL-12B polymorphism showed linkage disequilibrium (χ(2) = 5.64, P = 0.02). Linkage disequilibrium of polymorphisms is reported in the IL-12 gene in patients with HCV infection and contributes to the understanding of patient genotype and expected production of IL-12, responding to infection.
Assuntos
Haplótipos , Hepatite C/genética , Interleucina-12/genética , Desequilíbrio de Ligação , Polimorfismo Genético , Regiões 3' não Traduzidas , Sequência de Bases , Feminino , Frequência do Gene , Hepacivirus/genética , Hepacivirus/imunologia , Hepatite C/imunologia , Hepatite C/virologia , Humanos , Subunidade p40 da Interleucina-12/genética , Íntrons , Masculino , Dados de Sequência Molecular , Regiões Promotoras GenéticasRESUMO
Several cell surface molecules have hepatitis C virus (HCV) binding properties and may serve as receptors facilitating viral entry into cells. The large extracellular loop (LEL) of CD81 has been shown to bind the HCV envelope protein E2 with several critical residues for the CD81-HCV-E2 interaction. It was hypothesised that variation in the CD81 LEL sequence may modify susceptibility to HCV infection. HCV RNA negative patients with spontaneous viral clearance (RNA -ve); HCV RNA positive cases, who are affected chronically (RNA +ve); and patients at high risk of HCV infection, exposed but uninfected patients (EU) were studied. Genomic DNA was extracted from whole blood samples and four exons of the CD81 LEL gene were amplified by PCR and sequenced. The cDNA derived from CD81 (≈700 bp) was sequenced following RNA extraction from peripheral blood mononuclear cells. Patients, who are RNA positive, RNA negative, and exposed uninfected were sequenced for four DNA sections (A, B, C, and D). Sixty-two (43M:19F) patients, from all the patient cohorts, were sequenced and compared for the C section alone (which encompasses the important binding region of the molecule for envelope protein) including 21 (14M:7F) HCV RNA negative, 15 (10M:5F) HCV RNA positive and 26 (20M:6F) exposed uninfected and no sequence differences were observed. The entire CD81 sequence from cDNA was obtained in 23 cases-11 RNA -ve, 5 RNA +ve and 7 EU. In 7 of the 23 cases, the nucleotides were confirmed with the genomic sequence (4 RNA -ve and 3 EU cases). No sequence variation was found in any of the patients studied by either method, including gene sections encoding the residues most important for CD81-HCV E2 binding. The LEL of CD81 is a molecule that is highly conserved. No differences in nucleotide sequence influencing susceptibility to, or outcome of HCV infection or evidence of methylation of the gene were found.
Assuntos
Predisposição Genética para Doença , Hepatite C/genética , Tetraspanina 28/genética , Adulto , Sequência de Aminoácidos , Sequência de Bases , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência MolecularRESUMO
Hepatitis C virus (HCV) is a pathogen causing chronic hepatitis, cirrhosis, and liver cancer occurring in about 3% of the world's population. Most individuals infected with HCV develop persistent viremia. Oxidative stress may play an important role in the pathogenesis of a number of diseases including HCV infection and diabetes mellitus. Polymorphisms in the antioxidant genes may determine cellular oxidative stress levels as a primary pathogenic role in HCV and/or in its complications. Patients with HCV and normal, healthy controls were investigated for a superoxide dismutase (SOD-2) polymorphism in the mitochondrial targeting sequence with Ala/Val (C-9T) substitution. Polymorphisms in antioxidant gene SOD-2 were carried out by PCR, restriction fragment length polymorphism assays and by polyacrylamide gel electrophoresis. For the SOD-2 polymorphism, the RNA positive group showed a higher percentage of "CT" genotype than the RNA negative group (89.3% vs. 66.1%, P = 0.001, χ(2) = 11.9). The RNA negative group had more TT genotypes than the RNA positive group (27.4% vs. 6.80%, P = 0.01, χ(2) = 11.6). The exposed uninfected group had an increased frequency of the "CT" genotype (86.2% vs. 66.1%, P = 0.02, χ(2) = 5.5). The RNA positives had a higher frequency of the "CT" from the normal controls (72.1% vs. 89.2%, P = 0.005, χ(2) = 7.8).
Assuntos
Predisposição Genética para Doença , Hepacivirus/imunologia , Hepatite C/imunologia , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Adulto , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Polimorfismo de Nucleotídeo Único , Estudos RetrospectivosRESUMO
Neurological disorders include a variety of conditions, including Alzheimer's disease, motor neuron disease and Parkinson's disease, affecting longevity and quality of life, and their pathogenesis is associated with oxidative stress. Several of the chronic neurodegenerative pathologies of the CNS share some common features, such as oxidative stress, inflammation, synapse dysfunctions, protein misfolding and defective autophagia. Neuroinflammation can involve the activation of mast cells, contributing to oxidative stress, in addition to other sources of reactive oxygen species. Antioxidants can powerfully neutralize reactive oxygen species and free radicals, decreasing oxidative damage. Antioxidant genes, like the manganese superoxide dismutase enzyme, can undergo epigenetic changes that reduce their expression, thus increasing oxidative stress in tissue. Alternatively, DNA can be altered by free radical damage. The epigenetic landscape of these genes can change antioxidant function and may result in neurodegenerative disease. This imbalance of free radical production and antioxidant function increases the reactive oxygen species that cause cell damage in neurons and is often observed as an age-related event. Increased antioxidant expression in mice is protective against reactive oxygen species in neurons as is the exogenous supplementation of antioxidants. Manganese superoxide dismutase requires manganese for its enzymic function. Antioxidant therapy is considered for age-related neurodegenerative diseases, and a new mimetic of a manganese superoxide dismutase, avasopasem manganese, is described and suggested as a putative treatment to reduce the oxidative stress that causes neurodegenerative disease. The aim of this narrative review is to explore the evidence that oxidative stress causes neurodegenerative damage and the role of antioxidant genes in inhibiting reactive oxygen species damage. Can the neuronal environment of oxidative stress, causing neuroinflammation and neurodegeneration, be reduced or reversed?
RESUMO
This article was migrated. The article was not marked as recommended. Trust is an essential component of developing bonds and, in particular, the relationship between teacher and learner. The cumulative effects of pedagogy, curriculum, content, and delivery in teaching and learning of medical students (MS) are well established and the importance of the relationship between student and teachers, with particular reference to the concept of trust is reviewed, addressing aspects of intention, capability, character, and integrity. Trust is often perceived as a soft quality with respect to education, however trust actually provides an environment of hope and inspirational optimism. In such an environment teachers and learners can be authentic about their 'best selves', developing good character with high emotional intelligence (EI), where honest reflection is the key to enhanced integrity with transparent intentions in their relationships. Trusting relationships in education instil mutual respect, enhance collaboration, and promote the independent thinking that results from transparent and kind mutual interactions. Indeed, loyalty and commitment to values and goals ensures the success of the learning environment. Neuroscience and psychology experiments demonstrate recent evidence to support the importance of trust in relationships that can be considered relevant to teaching and learning. The expression of hormones and brain function, associated with trusting relationships and interpersonal bonding is explored.
RESUMO
Most people with hepatitis C virus (HCV) develop chronic infection with persistent viremia. Resolution of infection is associated with antiviral cellular immune responses of T helper 1 (Th1) type. Interleukin-12 (IL-12) is a key cytokine in the generation of Th1 responses, and functionally relevant polymorphisms of the IL12B gene and its promoter have been described recently. We sought an association between three IL12B polymorphisms and outcome of HCV infection in 195 HCV antibody-positive patients; 123 were chronically infected with detectable HCV RNA, and 72 had spontaneously resolved infection testing repeatedly negative for HCV RNA. Genotyping was performed for a single nucleotide polymorphism (SNP) in the 3'-UTR (1188A/C) of the IL12B gene and for 4-bp insertion/deletion polymorphisms in the IL12B promoter region and in the intron 4 region of the IL12B gene. We found chronically infected patients were significantly more likely than those with resolved HCV infection to be homozygous for the 3'-UTR A allele (66% vs. 50%; chi-square = 4.12, p = 0.04 with Yates correction), which has been associated with lower IL-12 production. No other significant association was found. Our findings support the concept that an individual's genetically determined ability to produce IL-12 is another factor that can influence the outcome of HCV infection.
Assuntos
Hepatite C/genética , Hepatite C/imunologia , Interleucina-12/genética , Polimorfismo Genético , Subunidades Proteicas/genética , Regiões 3' não Traduzidas , Adulto , Alelos , Sequência de Bases , Estudos de Casos e Controles , DNA/genética , Feminino , Haplótipos , Hepatite C/virologia , Hepatite C Crônica/genética , Hepatite C Crônica/imunologia , Hepatite C Crônica/virologia , Homozigoto , Humanos , Interleucina-12/biossíntese , Subunidade p40 da Interleucina-12 , Íntrons , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Prognóstico , Regiões Promotoras Genéticas , Subunidades Proteicas/biossíntese , Deleção de SequênciaRESUMO
UNLABELLED: The effective treatment of diabetes and the prevention of diabetic complications may be improved by a better understanding of the antioxidant function of intracellular defences against oxidative stress. Polymorphisms in antioxidant genes may determine cellular oxidative stress levels as a primary pathogenic role in diabetes and/or in its complications. SOD-2 was investigated in patients with type 1 diabetes mellitus (T1DM) to ascertain if specific genotypes have any protective influences in the pathogenic mechanisms in diabetes and/or in several different complications, including retinopathy, nephropathy and diabetic controls compared to normal healthy controls. METHOD: 278 (136M:142F) T1DM patients and 135 (72M:63F) normal, healthy controls were investigated for SOD-2 polymorphism in the mitochondrial targeting sequence with Ala/Val (C-9T) substitution. RESULTS: A significant difference in the C-9-T genotype was observed between patients and normal controls but not between diabetic controls and patients with complications. There were significantly more of the diabetic control (DC, n=62) group (11.3%) than the patients with diabetic nephropathy (DN, n=73) (1.4%) with the CC genotype (p=0.03 and χ(2)=4.27, OR=9.16 (1.08Assuntos
Diabetes Mellitus Tipo 1/genética
, Nefropatias Diabéticas/genética
, Estresse Oxidativo/genética
, Superóxido Dismutase/genética
, Adulto
, Antioxidantes/metabolismo
, Complicações do Diabetes/genética
, Complicações do Diabetes/patologia
, Diabetes Mellitus Tipo 1/patologia
, Nefropatias Diabéticas/patologia
, Feminino
, Frequência do Gene
, Estudos de Associação Genética
, Predisposição Genética para Doença
, Humanos
, Masculino
, Pessoa de Meia-Idade
, Polimorfismo de Nucleotídeo Único
, Superóxido Dismutase/metabolismo