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1.
Nat Commun ; 8: 14427, 2017 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-28205549

RESUMO

Bottom-up self-assembly of simple molecular compounds is a prime pathway to complex materials with interesting structures and functions. Coupled reaction systems are known to spontaneously produce highly ordered patterns, so far observed in soft matter. Here we show that similar phenomena can occur during silica-carbonate crystallization, the emerging order being preserved. The resulting materials, called silica biomorphs, exhibit non-crystallographic curved morphologies and hierarchical textures, much reminiscent of structural principles found in natural biominerals. We have used a fluorescent chemosensor to probe local conditions during the growth of such self-organized nanostructures. We demonstrate that the pH oscillates in the local microenvironment near the growth front due to chemical coupling, which becomes manifest in the final mineralized architectures as intrinsic banding patterns with the same periodicity. A better understanding of dynamic autocatalytic crystallization processes in such simple model systems is key to the rational development of advanced materials and to unravel the mechanisms of biomineralization.


Assuntos
Carbonatos/química , Cristalização/métodos , Nanoestruturas/química , Dióxido de Silício/química , Materiais Biomiméticos/química , Precipitação Química , Corantes Fluorescentes , Concentração de Íons de Hidrogênio , Microscopia de Fluorescência , Minerais , Técnicas de Sonda Molecular , Nanoestruturas/ultraestrutura
2.
J Immigr Minor Health ; 19(4): 876-882, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-27271956

RESUMO

Aims of the study are to investigate, in a cohort of patients affected by HCV chronic hepatitis with genotypes 1 and 4, the prevalence of interleukin 28B (IL28B) genotypes, the possible association between IL28B polymorphism and severity of liver damage, the role of IL28B CC as a predictor of outcome. 365 patients with HCV infection were observed between 2013 and 2014. Demographic, virological, biochemical, and genetic characteristics of each patient were investigated. Liver fibrosis was assessed by transient elastometry. Mean age of the patients (72.9 % males, 27.1 % females) is 50 years. 91.5 % % of patients are Caucasian, 8.5 % African. In the patients with HCV1 and HCV4 a higher frequency of IL28B CT is observed with a prevalence of 52.1 and 61.8 % respectively. As regards ethnic group, African people have a prevalence of 35.5 % for CC, while Caucasians have a prevalence of 23.8 % for CC. In our cohort, IL28B polymorphism does not show significant differences among ethnic groups and in HCV1 and HCV4 genotypes. As described in literature, IL28B CC genotype is confirmed as predictor of sustained virological response in both Caucasians and Africans. A significant correlation between liver fibrosis and IL28B polymorphism emerges.


Assuntos
Emigrantes e Imigrantes/estatística & dados numéricos , Hepatite C Crônica/etnologia , Hepatite C Crônica/genética , Interleucinas/genética , Adulto , Antivirais/uso terapêutico , População Negra/estatística & dados numéricos , Estudos de Coortes , Feminino , Genótipo , Hepatite C Crônica/complicações , Hepatite C Crônica/tratamento farmacológico , Humanos , Interferons , Itália/epidemiologia , Cirrose Hepática/etiologia , Cirrose Hepática/genética , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Fatores Socioeconômicos , Viremia/genética , População Branca/estatística & dados numéricos
3.
Chem Commun (Camb) ; 51(64): 12799-802, 2015 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-26166808

RESUMO

A nanostructure formed by the insertion in silica nanoparticles of a pyrene-derivatized cavitand, which is able to specifically recognize ecstasy in water, is presented. The absence of effects from interferents and an efficient electron transfer process occurring after complexation of ecstasy, makes this system an efficient fluorescent probe for this popular drug.


Assuntos
Corantes Fluorescentes/química , N-Metil-3,4-Metilenodioxianfetamina/análise , N-Metil-3,4-Metilenodioxianfetamina/química , Transporte de Elétrons , Modelos Moleculares , Conformação Molecular , Nanopartículas/química , Organofosfonatos/química , Dióxido de Silício/química
4.
Infection ; 42(4): 675-87, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24700252

RESUMO

PURPOSE: Human immunodeficiency virus (HIV-1)-infected patients frequently harbour hepatitis B and C viruses (HBV and HCV, respectively). Possible modifications of the natural history of hepatitis B may occur. The aim of this study was to characterise HBV diversity and evolutionary and mutational viral genome profiles in HIV-1/HBV coinfections. METHODS: HIV-1 and HBV markers determinations (Roche, FRG; Abbott, USA) and HBV genome-length retrospective analysis were performed in follow-up isolates from patients who were either stably HBsAg-negative with a low level of HBV DNA (occult hepatitis B infection, OBI) or HBsAg-positive with a high level of HBV DNA. Phylogenetic analysis (maximum likelihood method, MEGA5), statistical analysis and evolutionary rates calculation (d S/d N) were applied. RESULTS: Positive selection pressures in the PreS/S region and a significantly higher number of mutations in this region including the major hydrophilic region (MHR) and the "a" determinant were shown in HBsAg-negative (possibly OBI) compared to stably HBsAg-positive HIV-1/HBV subgenotypes D3/A2 coinfected patients. Mutants previously described in HIV-1/HBV coinfected patients were found. Known mutants Y100C, P127T and P120A associated to Y134H and S143T and new S mutants, which may potentially affect HBsAg expression and secretion and anti-HBs binding, were detected in baseline sera persisting up to the end of 9 years follow-up. Known mutations of BCP, Pre-C, C and X regions were also characterised. Natural mutants strictly known as being involved in diagnostic failure were not detected; however, numerous corresponding sites showed amino acid variations. CONCLUSIONS: Evolutionary and genotypic differences observed, particularly in the PreS/S region, between HBsAg-negative (OBI) and HBsAg-positive HIV-1/HBV coinfected patients, may contribute, in association with mutations of other genomic regions, to the HBsAg-negative phenotype.


Assuntos
DNA Viral/genética , Genoma Viral , Infecções por HIV/complicações , Vírus da Hepatite B/classificação , Vírus da Hepatite B/genética , Hepatite B Crônica/virologia , Mutação , Adulto , DNA Viral/química , Feminino , Seguimentos , Variação Genética , Genótipo , Vírus da Hepatite B/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Filogenia , Estudos Retrospectivos , Análise de Sequência de DNA
5.
Food Sci Technol Int ; 16(2): 179-86, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21339133

RESUMO

Turbidity of freshly squeezed apple juice is produced by a polydisperse suspension of particles coming from the cellular tissue. After precipitation of coarse particles by gravity, only fine-colloidal particles remain in suspension. Aggregation of colloidal particles leads to the formation of fractal structures. The fractal dimension is a measure of the internal density of these aggregates and depends on their mechanism of aggregation. Digitized images of primary particles and aggregates of depectinized, diafiltered cloudy apple juice were obtained by scanning electron microscopy (SEM). Average radius of the primary particles was found to be a = 40 ± 11 nm. Maximum radius of the aggregates, R(L), ranged between 250 and 7750 nm. Fractal dimension of the aggregates was determined by analyzing SEM images with the variogram method, obtaining an average value of D(f) = 2.3 ± 0.1. This value is typical of aggregates formed by rapid flocculation or diffusion limited aggregation. Diafiltration process was found to reduce the average size and polydispersity of the aggregates, determined by photon correlation spectroscopy. Average gyration radius of the aggregates before juice diafiltration was found to be R(g) = 629 ± 87 nm. Average number of primary particles per aggregate was calculated to be N = 1174.


Assuntos
Bebidas , Fractais , Malus/química , Filtração , Floculação , Microscopia Eletrônica de Varredura , Modelos Teóricos , Tamanho da Partícula
6.
Infection ; 37(4): 344-8, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19636498

RESUMO

AIM: To evaluate the virological and clinical events occurring during a 3-year follow-up in three patients who, after symptomatic acute hepatitis C (AHC), experienced subsequent episodes of HC virus (V)-related acute liver cell necrosis. PATIENTS AND METHODS: The three patients were investigated for viral variability in the core, E1/E2, and NS5b regions during different phases of infection, and a computer-assisted analysis of the variation of known predicted epitopes in the consensus sequence was performed. RESULTS: The first patient showed numerous genetic variations, which may be related to the maintenance of a chronic HCV infection state and to episodes of liver disease exacerbation. The second patient showed minimal viral variations associated with apparent resolution of the infection, but the same virus isolate, based on phylogenetic analysis, produced a second acute episode after the occult phase. The third patient, after the resolution of AHC, manifested a second episode of HCV infection by a different HCV sub-genotype. CONCLUSION: Episodes of HCV-related acute liver cell necrosis after AHC may be associated to different virological patterns, such as the establishment of a chronic HCV infection, a reactivation of an occult virus, or a reinfection by a different HCV genotype.


Assuntos
Epitopos/genética , Epitopos/imunologia , Hepacivirus/genética , Hepacivirus/imunologia , Hepatite C/imunologia , Hepatite C/patologia , Fígado/patologia , Necrose/patologia , Adulto , Genótipo , Hepatite C/virologia , Humanos , Masculino , Filogenia , Polimorfismo Genético , Análise de Sequência de DNA , Proteínas do Core Viral/genética , Proteínas do Envelope Viral/genética , Proteínas não Estruturais Virais/genética
7.
Epidemiol Infect ; 136(8): 1027-34, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17892633

RESUMO

A large outbreak of hepatitis A virus (HAV) infection occurred in 2004 in Campania, a region of southern Italy, with 882 cases reported between 1 January and 1 August. The local public health authorities and the Italian National Institute of Health carried out investigations in order to characterize the agent, identify the source of infection and the route of transmission, and implement appropriate control measures. A web-based reporting system enhanced the flow of information between public health authorities, providing real-time epidemic curves and frequency distributions. The same 1B HAV genotype was found in 90% of sera from a subset of patients with acute disease, suggesting a local common source. A case-control study in the municipality with the highest attack rate showed that raw seafood consumption, in particular if illegally sold in water, was strongly associated with HAV illness. Samples of seafood systematically collected from retailers were found contaminated by HAV.


Assuntos
Surtos de Doenças , Hepatite A/epidemiologia , Adolescente , Adulto , Idoso , Animais , Anticorpos Antivirais/análise , Estudos de Casos e Controles , Criança , Pré-Escolar , Controle de Doenças Transmissíveis/métodos , Feminino , Genótipo , Hepatite A/sangue , Hepatite A/virologia , Vírus da Hepatite A/classificação , Vírus da Hepatite A/genética , Vírus da Hepatite A/isolamento & purificação , Humanos , Lactente , Itália/epidemiologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Vigilância da População , Frutos do Mar/virologia
8.
J Food Sci ; 72(2): R11-20, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17995847

RESUMO

Rheological data on a food together with data on its composition and structure or microstructure should lead to understanding the interrelationships between them. A number of foods are dispersions of solids in liquids, liquids in liquids, or gas in liquids. The dispersed particles may be colloidal in nature with dimensions < 10 mum, or larger noncolloidal particles (> 10 mum). For both colloidal and noncolloidal dispersions (either in dilute or concentrated regimes), several theoretical equations exist that provide insights into the role of key rheological parameters, such as particle volume fraction and size, interparticle forces, and fractal dimension on their viscosity, yield stress, and modulus. When theoretical models cannot be easily applied to foods with complex structures, structural analysis and structure-based models provide insight into the role of solids loading and interparticle bonding on rheological behavior. In this review, recent studies on colloidal and noncolloidal food dispersions in which theoretical models as well as structural analysis were employed are discussed.


Assuntos
Coloides/química , Tecnologia de Alimentos , Modelos Teóricos , Tamanho da Partícula , Reologia , Relação Estrutura-Atividade , Propriedades de Superfície
9.
Eur J Clin Microbiol Infect Dis ; 25(8): 527-31, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16835740

RESUMO

Reported here are details of a simultaneous outbreak of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections that occurred in a hemodialysis centre in northern Italy, with three patients seroconverting for HBsAg and four patients seroconverting for HCV antibodies. Phylogenetic analysis of the E2 region of the isolates from HCV-seroconverted patients showed the sequences were grouped in the same distinct branch as in a chronically HCV-infected patient, suggesting that the chronically infected patient was the index case. For the patients with HBV infection, phylogenetic analysis showed strong clustering among the sequences of the three patients who seroconverted to HBsAg and no relatedness between them and the sequences of patients chronically infected with HBV. For one of the patients who seroconverted to HBsAg, the last test with negative results for HBV markers had been performed 18 months prior to HBsAg seroconversion. This patient may have been previously infected with HBV and is presumed to be the source of the outbreak. This report emphasizes the importance of using universal precaution measures and HBV vaccination to prevent the transmission of viral hepatitis among chronic hemodialysis patients.


Assuntos
Surtos de Doenças , Hepatite B/epidemiologia , Hepatite C/epidemiologia , Diálise Renal , Hepacivirus/classificação , Hepatite B/complicações , Hepatite B/prevenção & controle , Vírus da Hepatite B/classificação , Hepatite C/complicações , Hepatite C/prevenção & controle , Humanos , Imunização , Itália/epidemiologia , Equipe de Assistência ao Paciente , Vacinas contra Hepatite Viral/administração & dosagem
10.
J Clin Microbiol ; 43(4): 1902-9, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15815016

RESUMO

We analyzed hepatitis C virus (HCV) genotype 4 isolates circulating in the Alexandria District (Egypt) in terms of genetic divergence and the presence of different subtypes. Hypervariable region 1 (HVR1) and the NH2 region of the E2 protein were characterized, and the heterogeneity of subtype 4a isolates was evaluated by analyzing epitope frequencies, immunoproteasome prediction, and possible glycosylation patterns. The heterogeneity of the nucleotide sequences was greater than that found in previous studies, which reported only subtype 4a. Subtype 4a was most common (78% of cases), yet four new subtypes were found, with subtype 4m representing 11% of the cases and the other three subtypes representing another 11%. Substantial heterogeneity was also found when the intrasubtype 4a sequences were analyzed. Differences in the probability of glycosylation and in the positions of the different sites were also observed. The analysis of the predicted cytotoxic-T-lymphocyte epitopes showed differences in both the potential proteosome cleavage and the prediction score. The Egyptian isolates in our study also showed high variability in terms of the HVR1 neutralization epitope. Five of these isolates showed amino acid substitutions never previously observed (a total of six positions). Four of these residues (in four different isolates) were in positions involved in anchoring to the E2 glycoprotein core and in maintaining the HVR1 conformation. The results of this study indicate that HCV genotype 4 in Egypt is extremely variable, not only in terms of sequence, but also in terms of functional and immunological determinants. These data should be taken into account in planning the development of vaccine trials in Egypt.


Assuntos
Variação Genética , Hepacivirus/genética , Hepatite C Crônica/epidemiologia , Epidemiologia Molecular , Proteínas do Envelope Viral/genética , Sequência de Aminoácidos , Egito/epidemiologia , Genótipo , Hepacivirus/classificação , Hepatite C Crônica/virologia , Humanos , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , Proteínas não Estruturais Virais/genética
11.
Metabolism ; 53(9): 1202-7, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15334385

RESUMO

As small increments in insulin concentration profoundly affect lipolysis, our goal was to describe the free fatty acid (FFA) profile during the frequently sampled intravenous glucose tolerance test (FSIGT) and determine if both endogenous and exogenous insulin influenced the FFA profile. Thirteen subjects had both a glucose-only (GO-FSIGT) and insulin-modified FSIGT (IM-FSIGT). Both protocols were of 6 hours duration. At baseline an intravenous glucose bolus (0.3 g/kg) was given. In the IM-FSIGT, insulin was infused from 20 to 25 minutes (4 mU/kg. min). Six additional subjects had both an IM-FSIGT and a normal saline study (NS-Study). For the NS-Study, normal saline solution was infused instead of glucose and insulin. Fasting glucose, insulin, FFA and epinephrine concentrations were similar for all tests. Endogenous insulin peaked at 4 +/- 1 minute in both FSIGTs. The mean calculated peak time of exogenous insulin in the IM-FSIGT was 26 +/- 1 minute. Glucose concentrations were lower and epinephrine concentrations higher in the IM-FSIGT versus GO-FSIGT. During the FSIGTs, the FFA time course revealed four distinct phases, which did not differ between protocols. In phase I (0 to 11 minutes), FFA levels remained near basal (491 +/- 183 micromol/L); in phase II (11 to 79 minutes), FFA levels declined achieving a nadir of 139 +/- 63 micromol/L; in phase III (79 to 188 minutes), FFA levels rose linearly and reattained basal levels; and in phase IV (188 to 360 minutes), FFA levels rose above basal and plateaued at 732 +/- 214 micromol/L (P <.001). In the NS-Study, FFA levels remained near baseline (388 +/- 118 mEq/L) until 180 minutes and then trended upward to 618 +/- 258 micromol/L at 360 minutes. FFA concentrations from 180 to 360 minutes did not differ in the IM-FSIGT versus NS-Study. As the 4 FFA phases did not differ between protocols, the insulin effect on FFA levels in the FSIGT can be attributed to endogenous insulin. But the similarity in FFA levels from 180 to 360 minutes in the IM-FSIGT and NS-Study suggests diurnal variation and not a dynamic related to insulin or the FSIGT protocol is responsible for the final suprabasal FFA plateau.


Assuntos
Ácidos Graxos não Esterificados/sangue , Teste de Tolerância a Glucose , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Adulto , Glicemia/metabolismo , Índice de Massa Corporal , Epinefrina/sangue , Feminino , Humanos , Hipoglicemiantes/sangue , Imunoquímica , Insulina/sangue , Medições Luminescentes , Masculino
12.
Arch Virol ; 149(7): 1423-33, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15221542

RESUMO

The presence of SENV and TTV infections among 50 patients who had undergone liver transplantation was evaluated. UTR amplification showed that 46 (92%) sera were positive. ORF-1 amplification showed that 25 (50%) patients were positive for either SENV (51.3%), TTV (10.8%), or both (37.8%) all confirmed by sequencing and phylogenetic analysis. SENV-D and SENV-H were the most prevalent viruses. The phylogenetic analysis of isolates showed that whereas SENV-D and SENV-G viruses showed sequence stability and strain persistence, SENV-H had cleared or mutated. Biological differences seem to exist among different genotypes in terms of viral replication and their persistence.


Assuntos
Infecções por Circoviridae/virologia , Circoviridae/genética , Circoviridae/isolamento & purificação , Transplante de Fígado , Torque teno virus/genética , Regiões 5' não Traduzidas , Circoviridae/classificação , DNA Viral/sangue , DNA Viral/química , Feminino , Genes Virais , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Fases de Leitura Aberta , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Torque teno virus/classificação , Torque teno virus/isolamento & purificação
13.
J Gen Virol ; 80 ( Pt 1): 157-167, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9934698

RESUMO

Poliovirus type 2 Sabin mutants were selected for drug resistance and dependence by plating on HeLa cell monolayers in the presence of 3(2H)-isoflavene, a compound related to dichloroflavan, which prevents the shut-off of host translation and poliovirus RNA and protein synthesis. The drug-resistant mutants grew equally well in the presence and in the absence of the drug, while the drug-dependent mutants only grew in the presence of the compound. One dependent and one resistant mutant were characterized biologically in more detail. The resistant mutant did not exhibit thermolability. The mild thermolability exhibited by the dependent mutant was not affected by the addition of 3(2H)-isoflavene, indicating that the substance does not bind the poliovirus type 2 Sabin capsid. The translation of viral proteins and the shut-off of host protein translation during cell infection were not inhibited in either mutant. In the absence of the drug, the cleavage of the precursor VPO, a step in virus protein processing, was affected in the dependent mutant. The dependence of the mutant on the drug was due to the inability of 75S empty particles to reach maturation: our results strongly suggest that this phenomenon is strictly dependent on the reduction of RNA synthesis, confirming the existence of a dynamic equilibrium between RNA production and genome encapsidation during the poliovirus replication cycle.


Assuntos
Antivirais/farmacologia , Isoflavonas/farmacologia , Mutação , Vacina Antipólio Oral , Poliovirus/efeitos dos fármacos , Centrifugação com Gradiente de Concentração , Reações Cruzadas , Resistência Microbiana a Medicamentos , Células HeLa , Calefação , Humanos , Poliovirus/genética , Poliovirus/crescimento & desenvolvimento , Vacina Antipólio Oral/genética , Biossíntese de Proteínas , RNA Viral , Sacarose , Temperatura , Transfecção , Proteínas Virais/biossíntese
14.
Arch Virol ; 143(8): 1599-615, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9739337

RESUMO

Two different strains of HIV-1, the lymphotropic HIV-IIIB and the monocytotropic HIV-Ba-L, were able to infect tertiary cultures of astrocytes established from the human embryonic brain. The infection did not require contact with infected cells, as astrocytes were exposed to infectious cell-free supernatants. Except for an early transient peak of p24 consistently observed after infection with HIV-Ba-L, the infection of astrocytes appeared to be nonproductive. However, viral production was always observed when infected astrocytes were cocultured with permissive cells (CEM-SS or monocytes). To exclude the possibility that undetectable levels of virus are chronically produced by astrocytes, we exposed permissive cells to p24 negative supernatants taken from infected cultures. In such conditions permissive cells were never infected. Infection of astrocytes by HIV-1 was further supported by the finding that provirus persisted in these cells. Indeed, by a nested PCR, we detected HIV-1 DNA even one month after infection. Moreover, at the transcriptional level we observed expression of the multiply spliced RNA (tat and nef primers). Noteworthy, this pattern of HIV-1 expression did not change appreciably when astrocytes were pretreated and cultivated in the presence of IL-1 beta. Altogether, our data support the concept that astrocytes may play a role in the spread of HIV-1 infection within the brain and in the pathogenesis of neuro-AIDS.


Assuntos
Astrócitos/virologia , HIV-1/fisiologia , Embrião de Mamíferos , Feminino , Proteína Glial Fibrilar Ácida/análise , Proteína do Núcleo p24 do HIV/biossíntese , Humanos , Interleucina-1/farmacologia , Gravidez
15.
Vaccine ; 16(9-10): 940-8, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9682341

RESUMO

Surveillance of suspected poliomyelitis cases was conducted in Albania from 1980 through 1995. A total of 93 cases were reported, 11 of which were clinically defined as poliomyelitis cases according to WHO criteria. Poliovirus was isolated from six subjects who were defined as contact vaccine-associated cases. Characterization of isolates by both antigenic and molecular methods showed that, in all cases, the disease was associated with type 2 or 3 polioviruses of vaccine origin with retromutations known to be associated with loss of Sabin attenuated phenotype. Infection occurred despite the fact that all patients had records of previous immunization with oral polio vaccine (OPV), suggesting a failure of vaccination. Four of the five patients from which poliovirus could not be isolated were classified as possible recipient vaccine-associated poliomyelitis on the basis of serology data (presence of antibodies against all three polioviruses) and the temporal association between the latest dose of vaccine received and onset of paralysis. Virological investigation on healthy contacts of the poliomyelitic patients yielded the isolation of a further 12 Sabin-like polio revertant viruses, mostly type 2 and 3. A detailed study of the non-polio acute flaccid paralysis (AFP) cases and their healthy contacts revealed the presence of several enteroviruses, namely Echo, coxsackie and, in three cases type 2 or 3 Sabin-like polioviruses. Overall, these data suggest the absence of circulation of wild-type poliovirus in Albania from 1980 to 1995, before the recent outbreak of poliomyelitis in 1996, and emphasize the need for active surveillance of AFP and laboratory characterization of virus isolates to monitor vaccination efficacy.


Assuntos
Poliomielite/epidemiologia , Poliomielite/etiologia , Vacina Antipólio Oral/efeitos adversos , Adolescente , Albânia/epidemiologia , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Feminino , Genoma Viral , Humanos , Lactente , Masculino , Mutação , Paralisia/epidemiologia , Paralisia/etiologia , Paralisia/virologia , Fenótipo , Poliomielite/virologia , Poliovirus/genética , Poliovirus/isolamento & purificação , Poliovirus/patogenicidade , Vacina Antipólio Oral/genética , Vacina Antipólio Oral/imunologia , Reação em Cadeia da Polimerase , Vigilância da População , Fatores de Risco
16.
J Clin Microbiol ; 36(7): 1912-8, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9650935

RESUMO

Mass vaccination has led poliomyelitis to become a rare disease in a large part of the world, including Western Europe. However, in the past 20 years wild polioviruses imported from countries where polio is endemic have been responsible for outbreaks in otherwise polio-free European countries. We report on the characterization of poliovirus isolates from a large outbreak of poliomyelitis that occurred in Albania in 1996 and that also spread to the neighboring countries of Yugoslavia and Greece. The epidemics involved 145 subjects, mostly young adults, and caused persisting paralysis in 87 individuals and 16 deaths. The agent responsible for the outbreak was isolated from 74 patients and was identified as wild type 1 poliovirus by both immunological and molecular methods. Sequence analysis of the genome demonstrated the involvement of a single virus strain throughout the epidemics, and genotyping analysis showed 95% homology of the strain with a wild type 1 poliovirus strain isolated in Pakistan in 1995. Neutralization assays with both human sera and monoclonal antibodies were performed to analyze the antigenic structure of the epidemic strain, suggesting its peculiar antigenic characteristics. The presented data underline the current risks of outbreaks due to imported wild poliovirus and emphasize the need to improve vaccination efforts and also the need to implement surveillance in countries free of indigenous wild poliovirus.


Assuntos
Surtos de Doenças , Poliomielite/virologia , Poliovirus/genética , Poliovirus/imunologia , Adolescente , Adulto , Albânia/epidemiologia , Anticorpos Monoclonais , Anticorpos Antivirais/sangue , Antígenos Virais/análise , Sequência de Bases , Criança , Pré-Escolar , Feminino , Grécia/epidemiologia , Humanos , Imunoglobulina M/sangue , Lactente , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Testes de Neutralização , Filogenia , Poliomielite/epidemiologia , Poliovirus/classificação , Poliovirus/isolamento & purificação , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNA , Iugoslávia/epidemiologia
17.
Clin Infect Dis ; 26(2): 419-25, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9502465

RESUMO

After >10 years without detection of any cases of wild virus-associated poliomyelitis, a large outbreak of poliomyelitis occurred in Albania in 1996. A total of 138 paralytic cases occurred, of which 16 (12%) were fatal. The outbreak was due to wild poliovirus type 1, isolated from 69 cases. An attack rate of 10 per 100,000 population was observed among adults aged 19-25 years who were born during a time of declining wild poliovirus circulation and had been vaccinated with two doses of monovalent oral poliovirus vaccines (OPVs) that may have been exposed to ambient temperatures for prolonged periods. Control of the epidemic was achieved by two rounds of mass vaccination with trivalent oral poliovirus vaccine targeted to persons aged 0-50 years. This outbreak underscores the ongoing threat of importation of wild poliovirus into European countries, the importance of delivering potent vaccine through an adequate cold chain, and the effectiveness of national OPV mass vaccination campaigns for outbreak control.


Assuntos
Surtos de Doenças , Paralisia/etiologia , Poliomielite/epidemiologia , Poliomielite/prevenção & controle , Vacina Antipólio Oral/imunologia , Adolescente , Adulto , Albânia/epidemiologia , Criança , Pré-Escolar , Humanos , Lactente , Pessoa de Meia-Idade , Poliomielite/transmissão , Poliomielite/virologia , Vacinação
18.
J Virol ; 71(9): 6905-12, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9261417

RESUMO

Immunity to poliomyelitis is largely dependent on humoral neutralizing antibodies, both after natural (wild virus or vaccine) infection and after inactivated poliovirus vaccine inoculation. Although the production of local secretory immunoglobulin A (IgA) antibody in the gut mucosa may play a major role in protection, most of information about the antigenic determinants involved in neutralization of polioviruses derives from studies conducted with humoral monoclonal antibodies (MAbs) generated from parenterally immunized mice. To investigate the specificity of the mucosal immune response to the virus, we have produced a library of IgA MAbs directed at Sabin type 1 poliovirus by oral immunization of mice with live virus in combination with cholera toxin. The epitopes recognized by 13 neutralizing MAbs were characterized by generating neutralization-escape virus mutants. Cross-neutralization analysis of viral mutants with MAbs allowed these epitopes to be divided into four groups of reactivity. To determine the epitope specificity of MAbs, virus variants were sequenced and the mutations responsible for resistance to the antibodies were located. Eight neutralizing MAbs were found to be directed at neutralization site N-AgIII in capsid protein VP3; four more MAbs recognized site N-AgII in VP1 or VP2. One IgA MAb selected a virus variant which presented a unique mutation at amino acid 138 in VP2, not previously described. This site appears to be partially related with site N-AgII and is located in a loop region facing the VP2 N-Ag-II loop around residue 164. Only 2 of 13 MAbs proved able to neutralize the wild-type Mahoney strain of poliovirus. The IgA antibodies studied were found to be produced in the dimeric form needed for recognition by the polyimmunoglobulin receptor mediating secretory antibody transport at the mucosal level.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Epitopos de Linfócito B/imunologia , Imunoglobulina A/imunologia , Vacina Antipólio Oral/imunologia , Poliovirus/imunologia , Animais , Anticorpos Antivirais/sangue , Especificidade de Anticorpos , Antígenos Virais/imunologia , Capsídeo/imunologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Testes de Neutralização , Conformação Proteica , Treonina , Células Tumorais Cultivadas
19.
Antiviral Res ; 27(1-2): 123-36, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7486950

RESUMO

Synthetic flavans, isoflavans and isoflavenes substituted with chloro, cyano and amidino groups were tested for their in vitro activity against poliovirus type 2, Coxsackie virus B4, echovirus type 6 and enterovirus 71. Plaque-reduction assays showed that substituted 3-(2H)-isoflavenes, carrying a double bond in the oxygenated ring, possess antiviral activity higher than that of the corresponding isoflavans. The most effective compounds were 4'-chloro-6-cyanoflavan and 6-chloro-4'-cyanoflavan. Studies on the mechanism of action of these two compounds suggested an effect on the early stages of viral replication.


Assuntos
Enterovirus/efeitos dos fármacos , Flavonoides/farmacologia , Amidinas/química , Cloretos/química , Cianetos/química , Enterovirus/metabolismo , Flavonoides/química , Flavonoides/toxicidade , Temperatura Alta , Humanos , Biossíntese de Proteínas/efeitos dos fármacos , RNA Viral/biossíntese , RNA Viral/efeitos dos fármacos , Células Tumorais Cultivadas , Proteínas Virais/biossíntese , Proteínas Virais/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos
20.
Antimicrob Agents Chemother ; 36(1): 95-9, 1992 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1317152

RESUMO

4',6-Dicyanoflavan (DCF), a new antirhinovirus compound, was shown to inhibit an early event of rhinovirus type 1B replication in HeLa cells. When DCF was present from the beginning of infection or was added no later than the first hour of infection, the compound completely prevented viral RNA and protein synthesis and the virus-induced shutoff of host translation. DCF had no adverse effect either on virus binding to the cell membrane or on virus penetration into cells, whereas it delayed the uncoating kinetics of neutral redencapsidated rhinovirus. DCF also prevented mild acid or thermal inactivation of virus infectivity, although it reversibly interacted with virions. These results suggest that the stabilizing effect of DCF on virion capsid conformation is responsible for uncoating inhibition.


Assuntos
Antivirais/farmacologia , Flavonoides/farmacologia , Rhinovirus/efeitos dos fármacos , Células Cultivadas , Células HeLa , Humanos , RNA Viral/biossíntese , RNA Viral/efeitos dos fármacos , Rhinovirus/metabolismo , Proteínas Virais/biossíntese
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