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Cobalt phthalocyanine multiwalled carbon nanotubes (CoPc-MWCNTs), a nanocomposite, are extraordinary electrochemical sensing materials. This material has attracted growing interest owing to its unique physicochemical properties. Notably, the metal at the center of the metal phthalocyanine structure offers an enhanced redox-active behavior used to design solid electrodes for determining varieties of analytes. This review extensively discusses current developments in CoPc-MWCNTs nanocomposites as potential materials for electrochemical sensors, along with their different fabrication methods, modifying electrodes, and the detected analytes. The advantages of CoPc-MWCNTs nanocomposite as sensing material and its future perspectives are carefully reviewed and discussed.
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Nanocompuestos , Nanotubos de Carbono , Materiales Inteligentes , Nanotubos de Carbono/química , Técnicas Electroquímicas/métodos , Nanocompuestos/química , ElectrodosRESUMEN
The supercapacitive properties of synthesized nickel phthalocyanine multiwalled carbon nanotubes nanocomposite on a glassy carbon electrode (NiPcMWCNTs-GCE) in four different electrolytes were investigated. The successful synthesis of the NiPcMWCNTs nanocomposite was confirmed by UV/vis electrode spectroscopy, SEM, TEM, EDX, and XRD techniques. The supercapacitive behaviors of the modified electrodes were examined in PBS, H2SO4, Na2SO4, and SAB electrolytes via CV and EIS techniques. The highest specific capacitance of 6.80 F g-1 was achieved for the GCE-NiPcMWCNTs electrode in 5 mM [Fe(CN)6]4-/3- prepared in 0.1 M PBS (pH 7). Charge transfer resistance Rct values of 0.06, 0.36, 0.61, and 1.98 kΩ were obtained for the GCE-NiPcMWCNTs in H2SO4, SAB, Na2SO4, and PBS electrolytes, respectively. Power density values, otherwise known as the "knee" frequency f°, of 21.2, 6.87, 2.22, and 1.68 Hz were also obtained for GCE-NiPcMWCNTs in H2SO4, Na2SO4, PBS, and SAB electrolytes, respectively. GCE-NiPcMWCNTs demonstrated the fastest electron transport capability and the highest power density in H2SO4 compared to the other electrolytes. Hence, GCE-NiPcMWCNTs-modified electrodes had high stability, high energy and power densities, and a large specific capacitance.
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The application of potassium bromate in the baking industry is used in most parts of the world to avert the human health compromise that characterizes bromates carcinogenic effect. Herein, various methods of its analysis, especially the electrochemical methods of bromate detection, were extensively discussed. Amperometry (AP), cyclic voltammetry (CV), square wave voltammetry (SWV), electrochemiluminescence (ECL), differential pulse voltammetry and electrochemical impedance spectroscopy (EIS) are the techniques that have been deployed for bromate detection in the last two decades, with 50%, 23%, 7.7%, 7.7%, 7.7% and 3.9% application, respectively. Despite the unique electrocatalytic activity of metal phthalocyanine (MP) and carbon quantum dots (CQDs), only few sensors based on MP and CQDs are available compared to the conducting polymers, carbon nanotubes (CNTs), metal (oxide) and graphene-based sensors. This review emboldens the underutilization of CQDs and metal phthalocyanines as sensing materials and briefly discusses the future perspective on MP and CQDs application in bromate detection via EIS.
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Bromatos/química , Técnicas Electroquímicas , Técnicas Biosensibles , Espectroscopía Dieléctrica , Electrodos , Monitoreo del Ambiente , Análisis de los Alimentos/métodos , Grafito , Humanos , Nanotubos de Carbono , Polímeros , Puntos Cuánticos , Agua/químicaRESUMEN
A simple, highly stereoselective one-pot methodology for the synthesis of novel 1,2-annulated sugars comprising of oxa-oxa and oxa-carbasugar fused skeletons from 2-nitrogalactal and a sugar-derived enone, obtained from 2-formylgalactal, promoted by KOtBu and CH3ONa respectively is described. Both processes rely on a domino double-Michael addition reaction resulting in the formation of three stereocenters in a single pot, including a quaternary center.
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Azúcares/síntesis química , Cristalografía por Rayos X , Ciclización , Modelos Moleculares , Conformación Molecular , Estereoisomerismo , Azúcares/químicaRESUMEN
Background: Influenza viruses have emerged as virulent pathogens causing considerable burden across the world. A thorough understanding of the pattern in occurrence of influenza globally is the need of hour. The present study deals with analysis of the dynamics of Influenza virus, especially the influence of seasonal change on viral circulation and causation of epidemics/pandemics in the context of subtropical region. Methods: During the 7 year (2009-2015) study, 36670 specimens were subjected to influenza analysis. Nasopharyngeal swabs collected from suspected patients from Chennai, Tamil Nadu, were tested and typed by real-time polymerase chain reaction assay. Results: During 2009 pandemic, among influenza A positives 95.16% were Apdm09, indicating that there was a predominant circulation of Apdm09. During postpandemic period, there were waves in the occurrence of Apdm09 which indicates fall in immunity with buildup in the susceptible population. Conclusion: In Chennai, Tamil Nadu, influenza positivity started with the onset of monsoon and peaks during the postmonsoon months throughout the study period. The assessment of meteorological factors compounding influenza activity can help in raising alerts to the public health officials of impending disaster which suggests that Influenza vaccination can be initiated before monsoon months in South India.
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Virus de la Influenza A/patogenicidad , Gripe Humana/virología , Humanos , India , Virus de la Influenza A/genética , Gripe Humana/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Estaciones del Año , Síndrome Respiratorio Agudo Grave/virologíaRESUMEN
Setting: All community health workers (CHWs) in rural Kenema District, Sierra Leone. Objective: CHW programmes provide basic health services to fill gaps in human health resources. We compared trends in the reporting and management of childhood malaria, diarrhoea and pneumonia by CHWs before, during and after the Ebola outbreak (2014-2016). Design: Retrospective cross-sectional study using programme data. Results: CHW reporting increased from 59% pre-outbreak to 95% during the outbreak (P < 0.001), and was sustained at 98% post-outbreak. CHWs stopped using rapid diagnostic tests for malaria mid-outbreak, and their use had not resumed post-outbreak. The average monthly number of presumptive treatments for malaria increased from 2931 pre-outbreak to 5013 during and 5331 post-outbreak (P < 0.001). The average number of monthly treatments for diarrhoea and pneumonia decreased from respectively 1063 and 511 pre-outbreak to 547 and 352 during the outbreak (P = 0.01 and P = 0.04). Post-outbreak pneumonia treatments increased (mean 1126 compared to pre-outbreak, P = 0.003), and treatments for diarrhoea returned to pre-outbreak levels (P = 0.2). Conclusion: The CHW programme demonstrated vulnerability, but also resilience, during and in the early period after the Ebola outbreak. Investment in CHWs is required to strengthen the health care system, as they can cover pre-existing gaps in facility-based health care and those created by outbreaks.
Contexte : Tous les travailleurs de santé communautaires (CHW) du district rural de Kenema, Sierra Leone.Objectif : Les programmes de CHW offrent des services de santé de base pour combler les lacunes en matière de ressources humaines en santé. Nous avons comparé les tendances du signalement et de prise en charge du paludisme, de la diarrhée et de la pneumonie de l'enfant par les CHW avant, pendant et après l'épidémie d'Ebola (20142016).Schéma : Étude rétrospective transversale sur les données du programme.Résultats : Les rapports des CHW ont augmenté de 59% avant l'épidémie à 95% pendant la flambée (P < 0,001), et se sont maintenus à 98% après la flambée. Les CHW ont arrêté d'utiliser les tests de diagnostic rapide pour le paludisme au milieu de l'épidémie et leur utilisation n'a pas repris après la flambée. Le nombre moyen mensuel de traitements présomptifs du paludisme a augmenté de 2931 avant la flambée à 5013 pendant et 5331 après la flambée (P < 0,001). Le nombre moyen mensuel de traitements pour diarrhée et pneumonie a diminué de 1063 et 511 avant la flambée à 547 et 352, respectivement, pendant la flambée (P = 0,01 et P = 0,04). Après la flambée, les traitements de pneumonie ont augmenté (moyenne 1126 comparée à avant la flambée, P = 0,003), tout comme les traitements pour diarrhée, qui sont remontés aux niveaux précédant la flambée (P = 0,2).Conclusion : Le programme des CHW a démontré sa vulnérabilité, mais également sa résilience, pendant la flambée et dans la brève période qui a suivi l'épidémie d'Ebola. Le renforcement du système de santé devrait investir dans les CHW car ils peuvent combler les lacunes pré-existantes des soins de santé basés dans les structures et celles créées par les épidémies.
Marco de referencia: Todos los agentes de salud comunitarios (CHW) en la zona rural del distrito de Kenema, en Sierra Leona.Objetivo: Los programas de CHWs prestan servicios básicos que compensan las deficiencias de recursos humanos del sistema de salud. En el estudio se comparó la evolución de las notificaciones y el tratamiento del paludismo, la diarrea y la neumonía en los niños por parte de los CHW, antes del brote epidémico de fiebre hemorrágica del Ébola; durante y después del mismo (20142016).Método: Fue este un estudio transversal retrospectivo a partir de los datos del programa.Resultado: La notificación por parte de los CHW aumentó de 59% antes del brote a 95% durante el mismo (P < 0,001) y permaneció estable en 98% después de la epidemia. Los CHW interrumpieron la utilización de las pruebas diagnósticas rápidas del paludismo en la mitad del período epidémico y no reanudaron su aplicación al finalizar el brote. El número promedio de tratamientos de presunción por paludismo aumentó de 2931 antes del brote a 5013 durante el mismo y 5331 después de la epidemia (P < 0,001). El promedio de tratamientos mensuales por diarrea y neumonía disminuyó respectivamente de 1063 y 511 antes del brote a 547 y 352 durante el mismo (P = 0,01 y P = 0,04). Después de la epidemia del Ébola los tratamientos por neumonía aumentaron (promedio 1126; P = 0,003) con respecto al período anterior al brote y los tratamientos por diarrea recuperaron las cifras anteriores a la epidemia (P = 0,2).Conclusión: Se puso de manifiesto la vulnerabilidad del programa de CHW a la epidemia del Ébola, pero se demostró también su capacidad de recuperación durante el brote y el período inicial después de la epidemia. El fortalecimiento de los sistemas de salud debe comportar una inversión en los CHW, que pueden cubrir las lagunas prexistentes de la atención institucional de la salud y las deficiencias que aparecen como resultado de las epidemias.
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Monoclonal antibodies (mAbs) contain short N-terminal signal peptides on each individual polypeptide that comprises the mature antibody, targeting them for export from the cell in which they are produced. The signal peptide is cleaved from each heavy chain (Hc) and light chain (Lc) polypeptide after translocation to the ER and prior to secretion. This process is generally highly efficient, producing a high proportion of correctly cleaved Hc and Lc polypeptides. However, mis-cleavage of the signal peptide can occur, resulting in truncation or elongation at the N-terminus of the Hc or Lc. This is undesirable for antibody manufacturing as it can impact efficacy and can result in product heterogeneity. Here, we describe a truncated variant of the Lc that was detected during a routine developability assessment of the recombinant human IgG1 MEDI8490 in Chinese hamster ovary cells. We found that the truncation of the Lc was caused due to the use of the murine Hc signal peptide together with a lambda Lc containing an SYE amino acid motif at the N-terminus. This truncation was not caused by mis-processing of the mRNA encoding the Lc and was not dependent on expression platform (transient or stable), the scale of the fed-batch culture or clonal lineage. We further show that using alternative signal peptides or engineering the Lc SYE N-terminal motif prevented the truncation and that this strategy will improve Lc homogeneity of other SYE lambda Lc-containing mAbs. Biotechnol. Bioeng. 2017;114: 1970-1977. © 2017 Wiley Periodicals, Inc.
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Anticuerpos Monoclonales/genética , Cadenas Ligeras de Inmunoglobulina/genética , Ingeniería de Proteínas/métodos , Señales de Clasificación de Proteína/genética , Secuencia de Aminoácidos/genética , Animales , Células CHO , Cricetulus , Humanos , Datos de Secuencia Molecular , Relación Estructura-ActividadRESUMEN
Dengue is a public health problem with an increasing global incidence and geographic distribution in almost all tropical and subtropical countries, with a transition from epidemic to endemic occurrence. In this study, we report a six-year analysis (2009-2014) performed at the Department of Virology, King Institute of Preventive Medicine, Chennai, Tamil Nadu, India. Our data confirm earlier findings that dengue is highly endemic in Chennai. In the present study, 10,099 serum samples from suspected dengue cases were tested for IgM ELISA (NIV Capture) and IgG Panbio ELISA (Australia). Of these suspected cases 6,798 and 3,301 were pediatric and adult cases, respectively, and 1,927 (19.08 %) were confirmed serologically as dengue. Of these, 1,752 (25.7 %) and 175 (5.3 %) were pediatric and adult cases, respectively. The aim of this study was to highlight the occurrence of DHF and DSS, mainly among the pediatric population, in which the infection causes higher mortality and morbidity. The overall positivity was higher in the pediatric group than in the adults. Detection of both IgM and IgG positivity will be useful for monitoring infection rates, the disease spectrum, and the prevalence of the different serotypes, which will give us insight about the circulating serotypes and pathogenicity. These data will be valuable for providing an early warning to predict an impending epidemic leading to major clinical manifestations of DHF and DSS.
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Dengue/epidemiología , Dengue/patología , Enfermedades Endémicas , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Anticuerpos Antivirales/sangre , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , India/epidemiología , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Estudios Seroepidemiológicos , Adulto JovenRESUMEN
BACKGROUND & OBJECTIVES: Human parainfluenza virus (HPIV) accounts for a significant proportion of lower respiratory tract infections in children as well as adults. This study was done to detect the presence of different subtypes of HPIV from patients having influenza like illness (ILI). METHODS: Throat and nasal swabs from 232 patients with ILI who were negative for influenza viruses were tested by multiplex reverse transcription polymerase chain reaction(mRT-PCR) for the detection of human parainfluenza virus. All samples were inoculated in rhesus monkey kidney (LLC-MK2) cell line. RESULTS: Of the 232 samples, 26(11.2%) were positive by mRT-PCR and nine (34.6%) showed cytopathic effect with syncytium formation for HPIV and all were HPIV-3 serotype, other serotypes like 1,2,4 were negative. The HPIV-3 strains (HN gene) were sequenced and analysed. Two novel mutations were identified at amino acid residues 295 and 297. INTERPRETATION & CONCLUSIONS: The mRT-PCR assay offers a rapid, sensitive and accurate diagnostic method for detection of HPIV which enables early detection and control. In our study there was a predominance of HPIV among 1-5 yr age group and the school going age group was less affected. Further studies need to be done to characterize HPIV isolated from different parts of the country.
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Virus de la Parainfluenza 1 Humana/aislamiento & purificación , Virus de la Parainfluenza 2 Humana/aislamiento & purificación , Infecciones por Paramyxoviridae/virología , Humanos , India , Virus de la Parainfluenza 1 Humana/genética , Virus de la Parainfluenza 2 Humana/genética , Infecciones por Paramyxoviridae/fisiopatologíaAsunto(s)
Virus de la Encefalitis Japonesa (Especie)/aislamiento & purificación , Encefalitis Japonesa , Adolescente , Adulto , Niño , Preescolar , Encefalitis Japonesa/sangre , Encefalitis Japonesa/epidemiología , Encefalitis Japonesa/prevención & control , Humanos , India , Lactante , Recién NacidoRESUMEN
BACKGROUND: Coxsackie B viruses (genus, Enterovirus; family, Picornaviridae) can cause aseptic meningitis, encephalitis, pleurodynia, and fatal myocarditis, and are implicated in the pathogenesis of dilated cardiomyopathy. The differentiation of the group B Coxsackieviruses into their subtypes has potential clinical and epidemiological implications. OBJECTIVE: In this study, we developed a one-step, single-tube genogroup-specific reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the detection of group B Coxsackie genomes targeting 5' UTR region. MATERIALS AND METHODS: The amplification can be obtained in less than 1 hour by incubating all the reagents in a single tube with reverse transcriptase and Bst DNA polymerase at 63°C. Detection of gene amplification could be accomplished by agarose gel electrophoresis and the monitoring of gene amplification can also be visualised with the naked eye by using SYBR green I fluorescent dye. RESULTS: A total of 40 samples comprising 31 positive samples and 9 negative samples were used in this study for comparative evaluation. The results were compared with those from Real-Time Polymerase Chain Reaction (RT-PCR). None of the RT-PCR-positive samples were missed by RT-LAMP, thereby indicating a higher sensitivity of the RT-LAMP assay. CONCLUSION: Thus, due to easy operation without a requirement of sophisticated equipment and skilled personnel, the RT-LAMP assay reported here is extremely rapid, cost-effective, highly sensitive, and specific and has potential usefulness for rapid detection of non-polio enterovirus (NPEV) not only by well-equipped laboratories but also by peripheral diagnostic laboratories with limited financial resources in developing countries.
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Técnicas de Laboratorio Clínico/métodos , Infecciones por Coxsackievirus/diagnóstico , Enterovirus Humano B/aislamiento & purificación , Técnicas de Amplificación de Ácido Nucleico/métodos , ARN Viral/genética , ARN Viral/aislamiento & purificación , Benzotiazoles , Técnicas de Laboratorio Clínico/economía , Infecciones por Coxsackievirus/virología , Diaminas , Electroforesis en Gel de Agar , Enterovirus Humano B/genética , Humanos , Técnicas de Amplificación de Ácido Nucleico/economía , Compuestos Orgánicos/metabolismo , Quinolinas , Sensibilidad y Especificidad , Coloración y Etiquetado/métodos , Temperatura , Factores de TiempoRESUMEN
BACKGROUND & OBJECTIVES: Dengue is one of the most important Arboviral diseases in man with outbreaks in Southeast Asia and India. We report a retrospective analysis of the dengue positivity in the referred samples for three years period (2006 to 2008) at the Department of Virology, King Institute of Preventive Medicine, Chennai, Tamil Nadu, India. METHODS: Serum samples from 1593 suspected cases (968 male and 625 female) were obtained. Of the 1593 cases screened, 1204 (75.5%) were paediatric cases and 389 (24.4%) adults. The samples were subjected to MAC ELISA and IgG ELISA. RESULTS: Of the 968 patients, 686 (43.0%) were positive, of which 579 (84.0%) were in the paediatric age group (<14 yr) and 107 (15.5%) were adults. The IgM positivity being 356 (36.7%) in males and 330 (52.8%) in females. Of the 686 positives, 113 (16.47%) were positive for both IgM and IgG denoting secondary infection. There was a noticeable increased occurrence during the cooler months and during the monsoon and post-monsoon months. INTERPRETATION & CONCLUSION: The dengue IgM seropositivity among the suspected cases indicates active dengue virus activity. Increase in the probable secondary infections especially in a country like ours where multiple serotypes are prevalent raises concern over probable increase in the incidence of the more serious DHF/DSS. Studies need to be done to identify circulating serotypes of dengue virus to design preventive strategies.
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Dengue/epidemiología , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , India/epidemiología , Masculino , Estudios RetrospectivosRESUMEN
Peripheral T-cell (TC) tolerance can be induced by tolerogenic antigen-presenting cell (APC). A prerequisite is the reduction or blockade of B7 of APC. Besides dendritic cell, B cells can be used as APC. Here, we show the generation B cells with reduced B7 expression by lentiviral transduction of endoplasmic reticulum (ER)-directed CTLA4. Vectors coding for the human CTL4-Ig were used for the human B-cell line Raji. Transduction efficiency was over 90% (MOI = 3). For the murine B-cell line A20 and for primary mouse B cells, murine CTLA4 was used. We show that B cells with reduced B7 expression reduce the antigen (Ag) specific TC proliferation in vitro. B cells expressing an ER-directed CTLA4 may reduce Ag-specific immune responses.
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Presentación de Antígeno/inmunología , Antígenos CD/inmunología , Linfocitos B/inmunología , Antígeno B7-1/inmunología , Tolerancia Inmunológica/inmunología , Activación de Linfocitos/inmunología , Animales , Células Presentadoras de Antígenos/inmunología , Células Presentadoras de Antígenos/metabolismo , Antígenos CD/genética , Antígenos CD/metabolismo , Linfocitos B/metabolismo , Antígeno B7-1/metabolismo , Antígeno CTLA-4 , Línea Celular , Retículo Endoplásmico/inmunología , Retículo Endoplásmico/metabolismo , Técnicas de Transferencia de Gen , Vectores Genéticos , Humanos , Lentivirus/genética , RatonesRESUMEN
Partially purified methanolic extract of Cissus quadrangularis (belonging to Vitaceae member, South Indian medicinal plant) have been explored for antiviral activity and their phytochemical characterisation. In vitro antiviral activity against HSV type1 and 2, and Vero cells at non-cytotoxic concentration were determined. HSV1 and HSV2 showed more sensitivity against the partially purified compound. Phytochemical analysis showed the presence of the Steroids and Terpenoids.
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An element/compound that acts as an antioxidant as well as, can increase the oxidative stress offers a new approach in differentiation therapy. Experiments were carried out to determine the effect of selenite on DNA damage and glutathione peroxidase (GPx) activity in N-nitrosodiethylamine (DEN) induced, phenobarbital promoted rat hepatoma. Supra-nutritional level of selenite (4 ppm) was supplemented at either, before-initiation/after-initiation and/or during entire period of the study. At the end of experiment period (20 weeks), extent of DNA damage (alkaline comet assay), selenium concentration, and GPx activity were assessed on nodular tissue (NL) cells, surrounding liver (SL) cells, and whole liver tissue (control) cells. Hepatic selenium level and GPx activity were decreased in DEN and PB-administered animals, whereas the DNA damage was found to be increased in both NL and SL cells compared with control group. However, the DNA damage is more in SL cells than in NL cells. Pre-supplementation of selenite did not show any difference in DNA (strand breaks) damage, selenium, and GPx activity. Increased hepatic selenium concentration and GPx activity were observed in both NL and SL cells in post-supplementation and entire period of selenite supplemented animals compared to DEN + PB treated animals. However, DNA damage was increased in NL but decreased in SL cells. Supplementation of selenite alone for 16 or 20 weeks had shown increased DNA damage, selenium concentration, and GPx activity compared to normal control animals. In summary, cancer bearing animals increased DNA damage and decreased Se level and GPx activity in NL and SL cells and other organs in cancer bearing animals, supplementation of Se further provoked DNA damage (no change in pretreatment) in NL cells, however it decreased DNA damage SL cells and other organs (kidney, lungs, and spleen). On the other hand Se levels and GPx activity were increased in NL and SL cells and other organs of Se-supplemented rats (no difference in group 3 animals). These results demonstrate that, in addition to chemopreventive and chemotherapeutic role of selenite, it also prevents cellular DNA damage induced in cancerous condition.
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Carcinoma Hepatocelular/enzimología , Roturas del ADN de Doble Cadena/efectos de los fármacos , Glutatión Peroxidasa/metabolismo , Neoplasias Hepáticas/enzimología , Selenito de Sodio/farmacología , Alanina Transaminasa/metabolismo , Animales , Peso Corporal/efectos de los fármacos , Carcinoma Hepatocelular/inducido químicamente , Carcinoma Hepatocelular/fisiopatología , Ensayo Cometa , Dietilnitrosamina , Ingestión de Líquidos/efectos de los fármacos , Conducta Alimentaria/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/enzimología , Hígado/fisiopatología , Pruebas de Función Hepática , Neoplasias Hepáticas/inducido químicamente , Neoplasias Hepáticas/fisiopatología , Masculino , Tamaño de los Órganos/efectos de los fármacos , Fenobarbital , Ratas , Ratas Wistar , Selenio/metabolismo , Albúmina Sérica/metabolismoRESUMEN
Apoptosis and phagocytosis of apoptotic cells are crucial processes. At best the phagocytic machinery detects and swallows all apoptotic cells in a way that progression to secondary necrosis is avoided. Otherwise, inflammation and autoimmune diseases may occur. Most apoptotic cells are phagocytosed instantaneously in a silent fashion; however, some dying cells escape their clearance. If the cells are not cleared early, they lose membranes due to extensive shedding of membrane surrounded vesicles (blebbing) and shrink. It is unclear how apoptotic cells compensate their massive loss of plasma membrane. Here, we demonstrate that endoplasmic reticulum- (ER) resident proteins (calnexin, the KDEL receptor and a dysfunctional immunoglobulin heavy chain) were exposed at the surfaces of shrunken late apoptotic cells. Additionally, these cells showed an increased binding of lectins, which recognize sugar structures predominantly found as moieties of incompletely processed proteins in ER and Golgi. In addition the ER resident lipophilic ER-Tracker Blue-White DPX, and internal GM1 were observed to translocate to the cell surfaces during late apoptosis. We conclude that during blebbing of apoptotic cells the surface membrane loss is substituted by immature membranes from internal stores. This mechanism explains the simultaneous appearance of preformed recognition structures for several adaptor proteins known to be involved in clearance of dead cells.
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Apoptosis/fisiología , Membrana Celular/fisiología , Epítopos/fisiología , Membranas Intracelulares/fisiología , Lípidos de la Membrana/fisiología , Fosfatidilserinas/fisiología , Animales , Apoptosis/efectos de la radiación , Tamaño de la Célula , Células Cultivadas , Retículo Endoplásmico/fisiología , Citometría de Flujo , Humanos , Células Jurkat/patología , Células Jurkat/fisiología , Ratones , Microscopía Fluorescente , Neutrófilos/patología , Neutrófilos/fisiología , Coloración y EtiquetadoRESUMEN
Dying cells were basically unnoticed by scientists for a long time and only came back into the spotlight roughly 10 years ago. The process of recognition and uptake of apoptotic and necrotic cells is complex and failures in this process can contribute to the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). Here, we discuss the recognition and uptake molecules which are involved in an efficient clearance of dying cells in early and late phases of cell death. The exposure of phosphatidylserine (PS) is an early surface change of apoptosing cells recognized by several receptors and adaptor molecules. We demonstrated that dying cells have cell membranes with high lateral mobility of PS, which contribute to their efficient clearance. Changes of the glycoprotein composition of apoptotic cells occur later than the exposure of PS. We further observed that complement binding is an early event in necrosis and a rather late event in apoptosis. Complement, C-reactive protein (CRP), and serum DNase I act as back-up molecules in the clearance process. Finally, we discuss how the accumulation of secondary necrotic cells and cellular debris in the germinal centers of secondary lymph organs can lead to autoimmunity. It is reasonable to argue that clearance defects are major players in the development of autoimmune diseases such as SLE.
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Apoptosis , Enfermedades Autoinmunes/etiología , Animales , Autoinmunidad , Proteína C-Reactiva/fisiología , Proteínas del Sistema Complemento/fisiología , Desoxirribonucleasa I/fisiología , Humanos , Glicoproteínas de Membrana/fisiología , Fosfatidilserinas/fisiología , Componente Amiloide P Sérico/fisiologíaRESUMEN
Systemic lupus erythematosus (SLE) is characterized by a diverse array of autoantibodies, particularly against nuclear antigens, thought to derive from apoptotic and necrotic cells. Impaired clearance functions for dying cells may explain accumulation of apoptotic cells in SLE tissues, and secondary necrosis of these cells may contribute to the chronic inflammation in this disease. The exposure of phosphatidylserine (PS) and altered carbohydrates on dying cells are important recognition signals for macrophages. Furthermore, serum factors such as complement, DNase I, pentraxins (e.g. C-reactive protein) and IgM contribute to efficient opsonization and uptake of apoptotic and necrotic cells. Defects in these factors may impact the development of SLE in humans and mice in a variety of ways. We observed impaired clearance of apoptotic cells in lymph nodes and skin biopsies of humans with lupus, as well as intrinsic defects of macrophages differentiated in vitro from SLE patients' CD34+ stem cells, demonstrating that apoptotic cells are not properly cleared in a subgroup of patients with SLE. This altered mechanism for the clearance of dying cells may represent a central pathogenic process in the development and acceleration of this autoimmune disease.
Asunto(s)
Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/patología , Animales , Apoptosis , Autoinmunidad , Proteína C-Reactiva/fisiología , Proteínas del Sistema Complemento/fisiología , Desoxirribonucleasa I/fisiología , Humanos , Ratones , Fagocitos/fisiología , Fagocitosis , Fosfatidilserinas/fisiología , Componente Amiloide P Sérico/fisiología , Piel/patologíaRESUMEN
There is a lot of interest in the health benefits of dietary carotenoids and on the relationship of these compounds with smoke. In particular, it is unknown if the enhanced cancer risk observed in smokers following beta-carotene supplementation can be also found using other carotenoids. Here, we studied the effects of the tomato carotenoid lycopene on molecular pathways involved in cell cycle progression, apoptosis and survival in immortalized RAT-1 fibroblasts exposed to cigarette smoke condensate (TAR). Lycopene (0.5-2.0 microM) inhibited cell growth in a dose-and time-dependent manner, by arresting cell cycle progression and by promoting apoptosis in cells exposed to TAR. The arrest of cell cycle was independent of p53 and of 8-OH-dG DNA damage and related to a decreased expression of cyclin D1. Moreover, the carotenoid up-regulated apoptosis and down-regulated the phosphorylation of AKT and Bad in cells exposed to TAR. Such an effect was associated to an inhibition of TAR-induced expression of Cox-2 and hsp90, which is known to maintain AKT activity. This study suggests that lycopene, differently from beta-carotene, can exert protective effects against cigarette smoke condensate.
Asunto(s)
Apoptosis/efectos de los fármacos , Carotenoides/farmacología , Ciclina D1/metabolismo , Fibroblastos/citología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Humo/efectos adversos , Proteína Letal Asociada a bcl/metabolismo , 8-Hidroxi-2'-Desoxicoguanosina , Animales , Western Blotting , Ciclo Celular/efectos de los fármacos , Línea Celular Transformada , Proliferación Celular/efectos de los fármacos , Ciclooxigenasa 2/metabolismo , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Fibroblastos/efectos de los fármacos , Fibroblastos/enzimología , Licopeno , Fosfoproteínas/metabolismo , Ratas , Fumar/efectos adversos , Nicotiana , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
BACKGROUND & OBJECTIVE: Respiratory viral infections have a major impact on public health. Acute respiratory infections largely caused by viruses, are the most common illnesses experienced by otherwise healthy adults and children. Among the respiratory viruses, influenza viruses are known to cause outbreaks globally. Information on the activity of influenza virus in our country is limited and none from Chennai. The present study was carried out to isolate and identify the influenza virus serotypes causing acute respiratory infection in children attending a tertiary care centre at Chennai. METHODS: During January to December 2002, 240 children with acute respiratory infection attending the out patient clinic of Institute of Child Health were included by convenient sampling. Throat swabs were collected from 4 to 5 cases every week. Isolation of influenza virus was attempted by inoculating the sample in Madin Darby Canine Kidney (MDCK) cell line. The isolates were typed by haemagglutination inhibition test and confirmed by immunoflourescence assay. RESULTS: Virus isolation was positive in 30 (12.5%) of the 240 samples. Influenza A/H3N2/Panama/ 2000/99 was the predominant serotype isolated accounting for 24 (80%) of the 30 isolates. Influenza B/Sichuan/379/99 was isolated in 4 (13.33%) and a combination of Influenza A/H3N2 and B/Sichuan in 2 (6.6%) of the isolates. INTERPRETATION & CONCLUSION: Isolation of influenza A and B viruses indicated a significant activity of these viruses in Chennai. Peak activity was observed during and after the first spell of rain. The predominance of A/H3N2/ Panama is an indication that the Indian scenario is similar to the global picture of influenza activity.