Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 115
Filtrar
1.
Sci Rep ; 8(1): 4669, 2018 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-29549350

RESUMEN

The East Asian Summer Monsoon driven by temperature and moisture gradients between the Asian continent and the Pacific Ocean, leads to approximately 50% of the annual rainfall in the region across 20-40°N. Due to its increasing scientific and social importance, there have been several previous studies on identification of moisture sources for summer monsoon rainfall over East Asia mainly using Lagrangian or Eulerian atmospheric water vapor models. The major source regions for EASM previously proposed include the North Indian Ocean, South China Sea and North western Pacific. Based on high-precision and high-frequency 6-year measurement records of hydrofluorocarbons (HFCs), here we report a direct evidence of rapid intrusion of warm and moist tropical air mass from the Southern Hemisphere (SH) reaching within a couple of days up to 33°N into East Asia. We further suggest that the combination of direct chemical tracer record and a back-trajectory model with physical meteorological variables helps pave the way to identify moisture sources for monsoon rainfall. A case study for Gosan station (33.25°N, 126.19°E) indicates that the meridional transport of precipitable water from the SH accompanying the southerly/southwesterly flow contributes most significantly to its summer rainfall.

2.
J Med Entomol ; 55(3): 587-599, 2018 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-29444287

RESUMEN

Despite evidence of arbovirus activity in northwestern Uganda (West Nile Sub-region), there is very limited information on the mosquito fauna of this region. The only published study reported 52 mosquito species in northwestern Uganda but this study took place in 1950 and the information has not been updated for more than 60 yr. In January and June 2011, CO2 baited-light traps were used to collect 49,231 mosquitoes from four different locations, Paraa (9,487), Chobe (20,025), Sunguru (759), and Rhino Camp (18,960). Overall, 72 mosquito species representing 11 genera were collected. The largest number of distinct species was collected at Chobe (43 species), followed by Paraa (40), Sunguru (34), and Rhino Camp (25). Only eight of the 72 species (11.1%) were collected from all four sites: Aedes (Stegomyia) aegypti formosus (Walker), Anopheles (Cellia) funestus group, Culex (Culex) decens group, Cx. (Culex) neavei Theobald, Cx. (Culex) univittatus Theobald, Cx. (Culiciomyia) cinereus Theobald, Cx. (Oculeomyia) poicilipes (Theobald), and Mansonia (Mansonoides) uniformis (Theobald). Fifty-four species were detected in northwestern Uganda for the first time; however, these species have been detected elsewhere in Uganda and do not represent new introductions to the country. Thirty-three species collected during this study have previously been implicated in the transmission of arboviruses of public health importance.


Asunto(s)
Distribución Animal , Culicidae/fisiología , Animales , Culicidae/clasificación , Uganda
3.
J Phys Chem A ; 119(19): 4439-49, 2015 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-25405363

RESUMEN

Global-scale atmospheric measurements are used to investigate the effectiveness of recent adjustments to production and consumption controls on hydrochlorofluorocarbons (HCFCs) under the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) and to assess recent projections of large increases in hydrofluorocarbon (HFC) production and emission. The results show that aggregate global HCFC emissions did not increase appreciably during 2007-2012 and suggest that the 2007 Adjustments to the Montreal Protocol played a role in limiting HCFC emissions well in advance of the 2013 cap on global production. HCFC emissions varied between 27 and 29 kt CFC-11-equivalent (eq)/y or 0.76 and 0.79 GtCO2-eq/y during this period. Despite slower than projected increases in aggregate HCFC emissions since 2007, total emissions of HFCs used as substitutes for HCFCs and chlorofluorocarbons (CFCs) have not increased more rapidly than rates projected [Velders, G. J. M.; Fahey, D. W.; Daniel, J. S.; McFarland, M.; Andersen, S. O. The Large Contribution of Projected HFC Emissions to Future Climate Forcing. Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 10949-10954] for 2007-2012. HFC global emission magnitudes related to this substitution totaled 0.51 (-0.03, +0.04) GtCO2-eq/y in 2012, a magnitude about two times larger than emissions reported to the United Nations Framework Convention on Climate Change (UNFCCC) for these HFCs. Assuming accurate reporting to the UNFCCC, the results imply that developing countries (non-Annex I Parties) not reporting to the UNFCCC now account for nearly 50% of global HFC emissions used as substitutes for ozone-depleting substances (ODSs). Global HFC emissions (as CO2-eq) from ODS substitution can be attributed approximately equally to mobile air conditioning, commercial refrigeration, and the sum of all other applications.


Asunto(s)
Contaminantes Atmosféricos/análisis , Clorofluorocarburos/análisis , Cambio Climático , Monitoreo del Ambiente
4.
Nature ; 513(7517): 219-23, 2014 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-25209800

RESUMEN

The hydroxyl radical (OH) is a key oxidant involved in the removal of air pollutants and greenhouse gases from the atmosphere. The ratio of Northern Hemispheric to Southern Hemispheric (NH/SH) OH concentration is important for our understanding of emission estimates of atmospheric species such as nitrogen oxides and methane. It remains poorly constrained, however, with a range of estimates from 0.85 to 1.4 (refs 4, 7-10). Here we determine the NH/SH ratio of OH with the help of methyl chloroform data (a proxy for OH concentrations) and an atmospheric transport model that accurately describes interhemispheric transport and modelled emissions. We find that for the years 2004-2011 the model predicts an annual mean NH-SH gradient of methyl chloroform that is a tight linear function of the modelled NH/SH ratio in annual mean OH. We estimate a NH/SH OH ratio of 0.97 ± 0.12 during this time period by optimizing global total emissions and mean OH abundance to fit methyl chloroform data from two surface-measurement networks and aircraft campaigns. Our findings suggest that top-down emission estimates of reactive species such as nitrogen oxides in key emitting countries in the NH that are based on a NH/SH OH ratio larger than 1 may be overestimated.


Asunto(s)
Atmósfera/química , Radical Hidroxilo/química , Modelos Teóricos , Contaminantes Atmosféricos/química , Cloroformo/química , Simulación por Computador , Óxidos de Nitrógeno/química
5.
Intern Med J ; 43(6): 630-4, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23461358

RESUMEN

BACKGROUND AND AIMS: Depression and obstructive sleep apnoea are two common entities, with common symptoms that make identification of either condition difficult. Our aim was to examine, within a group of patients referred with snoring and obstructive sleep apnoea, (i) the prevalence of depression with the 14-question Hospital Anxiety and Depression Scale (HADS), (ii) the correlation between the two lead depression symptoms from the Mini-International Neuropsychiatric Interview (MINI) and HADS, and (iii) the relationship between depression symptoms with physiological markers of OSA. METHODS: An observational study of depression questionnaires in patients referred because of snoring to a sleep clinic within university-affiliated public teaching hospital. RESULTS: Ninety-seven per cent of 240 patients approached responded, and 32% had a positive HADS (score >16/42). The HADS and MINI significantly correlated (r = 0.736, P < 0.001). Fifty-three per cent had either doctor-diagnosed depression (28%) and/or a positive HADS or MINI (25%). HADS correlated with the degree of sleepiness (r = 0.252, P < 0.0001) and inversely with hypoxaemia (r=-0.231, P < 0.0003) but not with the frequency of apnoeas and hypopnoeas (r = 0.116, P > 0.05). CONCLUSION: Depending on classification, 32-53% of patients with snoring had depressive symptoms or were on treatment, which is significantly greater than the Australian average of 21%. A simplified depression questionnaire was validated. Severity of depression correlated with sleepiness and hypoxaemia but not with severity of sleep apnoea.


Asunto(s)
Depresión/epidemiología , Depresión/psicología , Apnea Obstructiva del Sueño/epidemiología , Apnea Obstructiva del Sueño/psicología , Ronquido/epidemiología , Ronquido/psicología , Adulto , Anciano , Depresión/diagnóstico , Femenino , Hospitales Universitarios , Humanos , Masculino , Persona de Mediana Edad , Polisomnografía/métodos , Prevalencia , Derivación y Consulta , Apnea Obstructiva del Sueño/diagnóstico , Ronquido/diagnóstico , Encuestas y Cuestionarios
6.
J Med Entomol ; 49(6): 1289-306, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23270157

RESUMEN

The mosquito fauna in many areas of western Uganda has never been studied and is currently unknown. One area, Bwamba County, has been previously studied and documented but the species lists have not been updated for >40 yr. This paucity of data makes it difficult to determine which arthropod-borne viruses pose a risk to human or animal populations. Using CO2 baited-light traps, from 2008 through 2010, 67,731 mosquitoes were captured at five locations in western Uganda including Mweya, Sempaya, Maramagambo, Bwindi (BINP), and Kibale (KNP). Overall, 88 mosquito species, 7 subspecies, and 7 species groups in 10 genera were collected. The largest number of species was collected at Sempaya (65 species), followed by Maramagambo (45), Mweya (34), BINP (33), and KNP (22). However, species diversity was highest in BINP (Simpson's Diversity Index 1-D = 0.85), followed by KNP (0.80), Maramagambo (0.79), Sempaya (0.67), and Mweya (0.56). Only six species Aedes (Aedimorphus) cumminsii (Theobald), Aedes (Neomelaniconion) circumluteolus (Theobald), Culex (Culex) antennatus (Becker), Culex (Culex) decens group, Culex (Lutzia) tigripes De Grandpre and De Charmoy, and Culex (Oculeomyia) annulioris (Theobald), were collected from all five sites suggesting large differences in species composition among sites. Four species (Aedes (Stegomyia) metallicus (Edwards), Anopheles (Cellia) rivulorum Leeson, Uranotaenia (Uranotaenia) chorleyi (Edwards), and Uranotaenia (Uranotaenia) pallidocephala (Theobald) and one subspecies (Aedes (Stegomyia) aegypti formosus (Walker)) were collected in Bwamba County for the first time. This study represents the first description of the mosquito species composition of Mweya, Maramagambo, BINP, and KNP. A number of morphological variations were noted regarding the postspiracular scales, hind tibia, and sternites that make Culex (Culex) neavei (Theobald) challenging to identify. At least 50 species collected in this study have previously been implicated in the transmission of arboviruses of public health importance suggesting a high potential for maintenance and transmission of a wide variety of arboviruses in western Uganda.


Asunto(s)
Biodiversidad , Culicidae , Animales , Insectos Vectores , Uganda
7.
Mucosal Immunol ; 4(4): 383-96, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21430654

RESUMEN

Heterosexual transmission of human immunodeficiency virus-1 (HIV-1), from men to women, involves exposure to infectious HIV-1 in semen. Therefore, the cellular and molecular processes that underlie HIV-1 transmission are closely interconnected with fundamental principles of human reproductive biology. Human ex vivo organ culture systems allow experimental reconstruction of HIV-1 transmission, using human semen and premenopausal cervicovaginal mucosal tissue, with specific emphasis on the progression from exposure to development of primary HIV-1 infection. Clearly, an isolated piece of human tissue cannot duplicate the full complexity of events in natural infections, but with correct observation of conventional medical and ethical standards, there is no opportunity to study HIV-1 exposure and primary infection in young women. Human mucosal organ cultures allow direct study of HIV-1 infection in a reproducible format while retaining major elements of complexity and variability that typify community-based HIV-1 transmission. Experimental manipulation of human mucosal tissue both allows and requires acquisition of new insights into basic processes of human mucosal immunology. Expanding from the current foundations, we believe that human organ cultures will become increasingly prominent in experimental studies of HIV-1 transmission and continuing efforts to prevent HIV-1 infection at human mucosal surfaces.


Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/inmunología , Síndrome de Inmunodeficiencia Adquirida/transmisión , VIH-1/fisiología , Cuello del Útero/citología , Cuello del Útero/inmunología , Cuello del Útero/virología , Progresión de la Enfermedad , Epitelio/inmunología , Epitelio/virología , Femenino , Heterosexualidad , Humanos , Masculino , Membrana Mucosa/inmunología , Membrana Mucosa/virología , Técnicas de Cultivo de Órganos , Semen/virología
8.
Neuroscience ; 171(3): 794-811, 2010 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-20875842

RESUMEN

We examined whether repeated exposure to the increasingly abused amphetamine (AMPH) derivative 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) results in long-lasting neurobehavioral changes, and further, the ability of contextual cues to modulate these changes. We focused on dorsal striatum, a brain region implicated in the formation of persistent drug-related habits. Rats were transported to a novel recording chamber and treated with once-daily injections (s.c.) of (±)-MDMA (5.0 mg/kg) or saline for 5 days, followed by a challenge injection 14 days later either in the same (Experiment 1) or different context (Experiment 2). Chronically implanted micro-wire bundles were used to record from populations of striatal neurons on days 1, 5, and challenge. Twenty-four hours after the last injection, brains were removed and processed using a modified Golgi method to assess changes in neuronal morphology. A sensitized locomotor response was observed following MDMA challenge in 11 of 12 rats in Experiment 1 (same context), whereas only 58% of rats (7 of 12) displayed sensitization in Experiment 2 (different context). Furthermore, several alterations in striatal electrophysiology were apparent on challenge day, but only in rats that displayed sensitization. Conversely, structural changes in striatal medium spiny neurons, such as increases in spine density, were observed in MDMA-treated rats regardless of whether they displayed behavioral sensitization. Thus, it appears that reorganization of synaptic connectivity in dorsal striatum may contribute to long-lasting drug-induced behavioral alterations, but that these behavioral alterations are subject to modification depending on individual differences and the context surrounding drug administration.


Asunto(s)
Conducta Animal/efectos de los fármacos , N-Metil-3,4-metilenodioxianfetamina/toxicidad , Neostriado/efectos de los fármacos , Neostriado/patología , Neuronas/efectos de los fármacos , Neuronas/patología , Inhibidores de Captación Adrenérgica/toxicidad , Animales , Conducta Animal/fisiología , Forma de la Célula/efectos de los fármacos , Forma de la Célula/fisiología , Electrofisiología/métodos , Masculino , Neostriado/fisiopatología , Neuronas/fisiología , Ratas , Ratas Sprague-Dawley , Tinción con Nitrato de Plata/métodos
9.
Neuroscience ; 153(1): 329-37, 2008 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-18353560

RESUMEN

The striatum, which processes cortical information for behavioral output, is a key target of Huntington's disease (HD), an autosomal dominant condition characterized by cognitive decline and progressive loss of motor control. Increasing evidence implicates deficient glutamate uptake caused by a down-regulation of GLT1, the primary astroglial glutamate transporter. To test this hypothesis, we administered ceftriaxone, a beta-lactam antibiotic known to elevate GLT1 expression (200 mg/kg, i.p., for 5 days), to symptomatic R6/2 mice, a widely studied transgenic model of HD. Relative to vehicle, ceftriaxone attenuated several HD behavioral signs: paw clasping and twitching were reduced, while motor flexibility, as measured in a plus maze, and open-field climbing were increased. Assessment of GLT1 expression in striatum confirmed a ceftriaxone-induced increase relative to vehicle. To determine if the change in behavior and GLT1 expression represented a change in striatal glutamate handling, separate groups of behaving mice were evaluated with no-net-flux microdialysis. Vehicle treatment revealed a glutamate uptake deficit in R6/2 mice relative to wild-type controls that was reversed by ceftriaxone. Vehicle-treated animals, however, did not differ in GLT1 expression, suggesting that the glutamate uptake deficit in R6/2 mice reflects dysfunctional rather than missing GLT1. Our results indicate that impaired glutamate uptake is a major factor underlying HD pathophysiology and symptomology. The glutamate uptake deficit, moreover, is present in symptomatic HD mice and reversal of this deficit by up-regulating the functional expression of GLT1 with ceftriaxone attenuates the HD phenotype.


Asunto(s)
Ceftriaxona/uso terapéutico , Cuerpo Estriado/efectos de los fármacos , Transportador 2 de Aminoácidos Excitadores/metabolismo , Ácido Glutámico/metabolismo , Enfermedad de Huntington/tratamiento farmacológico , Regulación hacia Arriba/efectos de los fármacos , Animales , Cuerpo Estriado/metabolismo , Modelos Animales de Enfermedad , Transportador 2 de Aminoácidos Excitadores/genética , Líquido Extracelular/efectos de los fármacos , Líquido Extracelular/metabolismo , Enfermedad de Huntington/fisiopatología , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Ratones , Ratones Transgénicos , Fenotipo , Transmisión Sináptica/efectos de los fármacos , Regulación hacia Arriba/genética
10.
J Neural Transm (Vienna) ; 114(11): 1365-75, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17576514

RESUMEN

Methylphenidate (MPH) is the drug of choice in the treatment of attention deficit and hyperactivity disorders. Although a popular drug, concentration-dependent electrophysiological alteration or impairment (functional toxicity) and reversibility, have not been quantified. This study used spontaneously active neuronal networks growing on microelectrode arrays (MEA) to investigate functional neurotoxicity of MPH by assessing its acute and sub-chronic electrophysiologic effects on auditory cortex networks (ACN) and frontal cortex networks (FCN) at concentrations that reflect clinical doses and overdoses. Acute exposure to 1-300 microM MPH induced concentration-dependent inhibition of spontaneous activity with spike rate IC(50) values (concentration inducing 50% inhibition) of 112.9 +/- 18.6 and 108.0 +/- 18.9 microM for ACNs and FCNs respectively. Sub-chronic exposure to 1 mM MPH for 24 h blocked all activity followed by partial spontaneous recovery after 15 h. Tyrosine hydroxylase immunocytochemistry analysis indicated positive staining of neurons, confirming the presence of catecholaminergic neurons in cultured cortex networks.


Asunto(s)
Estimulantes del Sistema Nervioso Central/toxicidad , Metilfenidato/toxicidad , Red Nerviosa/patología , Síndromes de Neurotoxicidad/patología , Potenciales de Acción/efectos de los fármacos , Animales , Corteza Auditiva/citología , Corteza Auditiva/patología , Corteza Auditiva/fisiopatología , Catecolaminas/fisiología , Células Cultivadas , Interpretación Estadística de Datos , Relación Dosis-Respuesta a Droga , Electrofisiología , Inmunohistoquímica , Ratones , Microelectrodos
11.
Arch Virol ; 150(4): 771-86, 2005 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15592895

RESUMEN

The dengue 2 virus (DENV-2) NS1 glycoprotein contains two potential sites for N-linked glycosylation at Asn-130 and Asn-207. NS1 produced in infected cells is glycosylated at both of these sites. We used site-directed mutagenesis of a DENV-2, strain 16681, full length infectious clone to create mutant viruses lacking the Asn-130, Asn-207 or both of these NS1 glycosylation sites in order to investigate the effects of deglycosylation. Ablation of both NS1 glycosylation sites resulted in unstable viruses that acquired numerous additional mutations; these viruses were not further characterized. Viruses altered at the Asn-130 site exhibited growth characteristics similar to the wild-type (WT) 16681 virus in LLC-MK(2) cells and reduced growth in C6/36 cells. Viruses mutated at the Asn-207 site achieved similar titers in LLC-MK(2) cells compared to WT, however, the appearance of cytopathic effect was delayed and growth of these viruses in C6/36 cells was also reduced compared to WT virus. The plaque size of mutant viruses altered at the Asn-130 site did not differ from that of the WT virus, while mutants altered at the Asn-207 site exhibited a reduced and mixed plaque size. Temperature sensitivity studies comparing the growth of the viruses at 37 degrees C and 39 degrees C showed no significant differences compared to the WT virus. Immunofluorescent antibody staining of infected cells showed that for WT 16681 virus or the Asn-130 site mutant viruses NS1 was located throughout the cytoplasm, however, Asn-207 site mutant virus NS1 protein appeared to be localized to the perinuclear region. Viruses deglycosylated at either site exhibited a significant reduction in mouse neurovirulence compared to the WT virus. The results of our studies indicate that glycosylation of the DENV-2 virus NS1 protein may influence NS1 protein processing/transport as well as the pathogenicity of the virus.


Asunto(s)
Virus del Dengue/fisiología , Proteínas no Estructurales Virales/metabolismo , Aedes/virología , Secuencia de Aminoácidos , Animales , Antígenos Virales/metabolismo , Secuencia de Bases , Línea Celular , Dengue , Virus del Dengue/genética , Virus del Dengue/crecimiento & desarrollo , Glicosilación , Ratones , Ratones Endogámicos ICR , Fenotipo , Replicación Viral
12.
Insect Mol Biol ; 13(6): 625-35, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15606811

RESUMEN

Arthropod-borne alphaviruses transmitted by mosquitoes almost exclusively use culicines; however, the alphavirus o'nyong-nyong (ONNV) has the unusual characteristic of being transmitted primarily by anopheline mosquitoes. This unusual attribute makes ONNV a valuable tool in the characterization of mosquito determinants of infection as well as a useful expression system in Anopheles species. We developed a series of recombinant alphaviruses, based upon the genome of ONNV, designed for the expression of heterologous genes. The backbone genome is a full-length infectious cDNA clone of ONNV from which wild-type virus can be rescued. Additional constructs are variants of the primary clone and contain the complete genome plus a duplicated subgenomic promoter element with a multiple cloning site for insertion of heterologous genes. We inserted a green fluorescent protein (GFP) gene downstream of this promoter and used it to characterize infection and dissemination patterns of ONNV within An. gambiae mosquitoes. These experiments allowed us to identify atypical sites of initial infection and dissemination patterns in this mosquito species not frequently observed in comparable culicine infections. The utility of these ONNVs for studies in anopheline mosquitoes includes the potential for identification of vector infection determinants and to serve as tools for antimalaria studies. Viruses that can express a heterologous gene in a vector and rapidly and efficiently infect numerous tissues in An. gambiae mosquitoes will be a valuable asset in parasite-mosquito interaction and interference research.


Asunto(s)
Alphavirus/genética , Anopheles/virología , Vectores Genéticos/genética , Animales , Células Cultivadas , ADN Complementario/genética , Técnicas de Transferencia de Gen , Proteínas Fluorescentes Verdes/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
13.
Med Vet Entomol ; 17(3): 235-43, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12941006

RESUMEN

In 1999 West Nile (WN) virus was introduced to North America where this flavivirus has spread rapidly among wildlife (especially birds) transmitted by various species of mosquitoes (Diptera: Culicidae). Increasing numbers of cases and deaths among humans, horses and other domestic animals require development of effective vaccines. 'ChimeriVax-West Nile(vet)' is being developed for use as a veterinary vaccine to protect against WN infection. This chimeric virus contains the pre-membrane (prM) and envelope (E) genes from the wild-type WN NY99 virus (isolated from a flamingo in New York zoo during the 1999 WN epidemic) in the backbone of yellow fever (YF) 17D vaccine virus. Replication kinetics of ChimeriVax-WN(vet) virus were evaluated in mosquito cell culture (Aedes albopictus C6/36), in WN vector mosquitoes [Culex tritaeniorhynchus Giles, Cx. nigripalpus Theobald and Cx. quinquefasciatus Say (Diptera: Culicidae)] and in YF vectors [Aedes aegypti (L) and Ae. albopictus (Skuse)], to determine whether these mosquitoes become infected through feeding on a viraemic vaccine, and their potential infectivity to transmit the virus. Growth of ChimeriVax-WN(vet) virus was found to be restricted in mosquitoes, compared to WN virus in Ae. albopictus C6/36 cells. When inoculated intrathoracically, ChimeriVax-WN(vet) and YF 17D viruses did not replicate in Cx. tritaeniorhynchus or Cx. nigripalpus; replication was very restricted compared to the wild-type WN virus in Cx. quinquefasciatus, Ae. aegypti and Ae. albopictus. When fed on hanging drops with ChimeriVax-WN(vet) virus (7.7 log10 PFU/mL), none of the Culex mosquitoes became infected; one Ae. albopictus and 10% of the Ae. aegypti became infected, but the titre was very low and virus did not disseminate to head tissue. ChimeriVax-WN(vet) virus had a replication profile similar to that of the attenuated vaccine virus YF 17D, which is not transmitted by mosquitoes. These results suggest that the natural mosquito vectors of WN and YF viruses, which may incidentally take a bloodmeal from a vaccinated host, will not become infected with ChimeriVax-WN(vet) virus.


Asunto(s)
Aedes/virología , Culex/virología , Vacunas Virales/síntesis química , Fiebre del Nilo Occidental/prevención & control , Virus del Nilo Occidental/inmunología , Animales , Chlorocebus aethiops , Proteínas Recombinantes de Fusión/síntesis química , Proteínas Recombinantes de Fusión/uso terapéutico , Células Vero , Vacunas Virales/uso terapéutico , Fiebre del Nilo Occidental/transmisión , Vacunas contra el Virus del Nilo Occidental , Virus del Nilo Occidental/crecimiento & desarrollo
14.
Magn Reson Med ; 50(2): 275-82, 2003 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12876703

RESUMEN

The purpose of this study was to investigate the changes in electrostatic and magnetic resonance (MR) properties observed when MR contrast agents (CAs) (Feridex, MION-46L, or G5-dendrimer-DOTA-Gd) are combined with transfection agents (TAs) under various conditions for use as a CA-TA complex basis for cellular labeling and MRI. CAs were incubated with various classes of TAs for 0-48 hr in solutions of varying concentrations and pH values. NMR relaxation rates (1/T(1), 1/T(2)), MRI and zeta potential (ZP) of CA-TA solutions were measured. TAs decreased the 1/T(1) and 1/T(2) of G5-DOTA-Gd, Feridex, and MION-46L by 0-95%. Altering the pH of G5-DOTA-Gd-TA decreased the T(1)-weighted signal intensity (SI) on MRI from 0 to 78%. Measured ZP values for G5-DOTA-Gd, Feridex, and MION-46L were -51, -41, and -2.0 mV, respectively. The TA LV had a negative ZP, while the other TAs had ZPs ranging from +20 to +65 mV. The alteration of the ZP and NMR relaxivities of the MR CAs, Feridex, MION-46L, and G5-DOTA-Gd by TAs has been demonstrated. These results enhance our understanding of the relationship between electrostatic and MR properties.


Asunto(s)
Células Cultivadas , Medios de Contraste , Imagen por Resonancia Magnética , Medios de Contraste/química , Dextranos , Electroquímica , Óxido Ferrosoférrico , Gadolinio , Compuestos Heterocíclicos/química , Concentración de Iones de Hidrógeno , Hierro/química , Lípidos/química , Nanopartículas de Magnetita , Compuestos Organometálicos/química , Óxidos/química , Transfección
15.
Arch Virol ; 148(6): 1085-93, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12756616

RESUMEN

Cell fusing agent virus (CFAV) is an RNA insect virus that was isolated from a line of Aedes aegypti mosquito cells and has been assigned to the family Flaviviridae, genus Flavivirus. We report here the first isolation of a CFA-like virus from field-collected mosquitoes. Mosquito larvae and pupae were sampled from flooded dambos in Central Province, Kenya during the short rain season of 1999. Specimens were reared to adults, identified and pooled by species and were tested for the presence of virus. Two virus isolates were obtained from two pools of Aedes macintoshi mosquitoes. The virus isolates replicated only in invertebrate cells in culture and not in vertebrate cells or in mice. The virus isolates did not antigenically cross-react with known arboviruses but were identified to family by reverse-transcriptase polymerase chain reaction (RT-PCR) performed using primers specific to alphaviruses, bunyaviruses and flaviviruses; only the flavivirus-specific primers produced a DNA fragment of the expected size. Nucleic acid sequencing of this fragment showed the two isolates to be nearly identical. Comparison of sequences to the GenBank database using BLAST identified the virus as most closely related to CFAV. Results from cross-neutralization tests suggested that, although the BLAST search indicated homology to CFAV, the virus isolated represented a new insect flavivirus. Detailed characterization of this new virus, described in Crabtree et al. [7], further supports this finding. We propose this new flavivirus be designated Kamiti River virus (KRV). This is the first isolation of a CFA-like virus from field-collected mosquitoes and indicates the presence of this group of viruses in nature.


Asunto(s)
Aedes/virología , Flaviviridae/clasificación , Flaviviridae/aislamiento & purificación , Virus de Insectos/clasificación , Virus de Insectos/aislamiento & purificación , Animales , Línea Celular , Desastres , Flaviviridae/genética , Flaviviridae/fisiología , Genotipo , Virus de Insectos/genética , Virus de Insectos/fisiología , Kenia , Larva/virología , Pruebas de Neutralización , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Agua/parasitología
16.
Arch Virol ; 148(6): 1095-118, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12756617

RESUMEN

We have described in the accompanying paper by Sang, et al., ([57], Arch Virol 2003, in press) the isolation and identification of a new flavivirus, Kamiti River virus (KRV), from Ae. macintoshi mosquitoes that were collected as larvae and pupae from flooded dambos in Central Province, Kenya. Among known flaviviruses, KRV was shown to be most similar to, but genetically and phenotypically distinct from, Cell fusing agent virus (CFAV). KRV was provisionally identified as an insect-only flavivirus that fails to replicate in vertebrate cells or in mice. We report here the further characterization of KRV. Growth in cell culture was compared to that of CFAV; although growth kinetics were similar, KRV did not cause the cell fusion that is characteristic of CFAV infection. The KRV genome was found to be 11,375 nucleotides in length, containing a single open reading frame encoding 10 viral proteins. Likely polyprotein cleavage sites were identified, which were most similar to those of CFAV and were comparable to those of other flaviviruses. Sequence identity with other flaviviruses was low; maximum identity was with CFAV. Possible terminal secondary structures for the 5' and 3' non-coding regions (NCR) were similar to those predicted for other flaviviruses. Whereas CFAV was isolated from insect cells in the laboratory, the isolation of KRV demonstrates the presence of an insect-only flavivirus in nature and raises questions regarding potential interactions between this virus and other mosquito-borne viruses in competent vector populations. Additionally, this virus will be an important tool in future studies to determine markers associated with flavivirus host specificity.


Asunto(s)
Aedes/virología , Flaviviridae/clasificación , Flaviviridae/genética , Virus de Insectos/clasificación , Virus de Insectos/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Chlorocebus aethiops , Cricetinae , Flaviviridae/química , Flaviviridae/crecimiento & desarrollo , Genes Virales/genética , Virus de Insectos/química , Virus de Insectos/crecimiento & desarrollo , Kenia , Riñón/citología , Riñón/virología , Larva/virología , Ratones , Datos de Secuencia Molecular , Filogenia , Células Vero , Proteínas Virales/química , Proteínas Virales/genética
17.
Virus Genes ; 23(2): 211-4, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11724276

RESUMEN

Thogoto virus is a tick-borne member of the family Orthomyxoviridae. Previously, based on the similarity in antigenic relationship by cross-neutralization test, all virus strains were concluded to have derived from the same origin. In this study, we obtained partial gene sequences of 4 genes (PB1-like protein, PA-like protein, glycoprotein, and nucleoprotein) of 8 Thogoto virus strains isolated in Africa, Asia, and Europe and studied the genetic variation and phylogeny. Unrooted phylogenetic trees created by both neighbor-joining and maximum likelihood methods based on nucleotide and amino acid sequences for 4 genes were mostly similar and revealed two lineages, Euro-Asian and African. Intra-lineage nucleotide sequence variation was greater in the Euro-Asian lineage than in the African lineage for all 4 genes. Furthermore, for the strains of Euro-Asian lineage, variations for two genes associated with RNA-dependent RNA polymerase activities were greater than those for glycoprotein or nucleoprotein gene, based on both nucleotide and amino acid sequence differences as well as on synonymous and nonsynonymous differences, indicating greater mutation rates for the polymerase activity genes in these strains.


Asunto(s)
Filogenia , Thogotovirus/genética , Secuencia de Bases , Cartilla de ADN , Datos de Secuencia Molecular , Thogotovirus/clasificación
18.
Science ; 292(5523): 1882-8, 2001 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-11337586

RESUMEN

The hydroxyl radical (OH) is the dominant oxidizing chemical in the atmosphere. It destroys most air pollutants and many gases involved in ozone depletion and the greenhouse effect. Global measurements of 1,1,1-trichloroethane (CH3CCl3, methyl chloroform) provide an accurate method for determining the global and hemispheric behavior of OH. Measurements show that CH3CCl3 levels rose steadily from 1978 to reach a maximum in 1992 and then decreased rapidly to levels in 2000 that were lower than the levels when measurements began in 1978. Analysis of these observations shows that global OH levels were growing between 1978 and 1988, but the growth rate was decreasing at a rate of 0.23 +/- 0.18% year(-2), so that OH levels began declining after 1988. Overall, the global average OH trend between 1978 and 2000 was -0.64 +/- 0.60% year(-1). These variations imply important and unexpected gaps in current understanding of the capability of the atmosphere to cleanse itself.

19.
Pediatr Neurosurg ; 34(4): 190-2, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11359111

RESUMEN

Refractory generalized convulsive status epilepticus in a 13-year-old boy was halted by left vagal nerve stimulation. Over the next 1.5 years, seizures have continued at a rate and severity which is significantly better than it had been in the year before insertion of the stimulator.


Asunto(s)
Estado Epiléptico/terapia , Nervio Vago/fisiología , Adolescente , Cuerpo Calloso/cirugía , Estimulación Eléctrica/métodos , Humanos , Cuidados Intraoperatorios , Masculino , Periodo Posoperatorio , Estado Epiléptico/cirugía
20.
Poult Sci ; 80(3): 306-13, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11261561

RESUMEN

Four experiments were conducted to compare the performance of broilers fed soybean meal (SBM) versus peanut meal (PNM) as protein sources. Ross x Ross 208 broiler chickens were placed in battery brooders (Experiments 1 to 3, four replicates of 8 chicks per treatment) and floor pens (Experiment 4, four replicates of 34 chicks per treatment). In Experiment 1, addition of 0, 0.1, 0.2, and 0.3% Thr to a corn-PNM-based diet increased 0 to 18 d BW gain (BWG; 0.374c vs. 0.495b vs. 0.508b vs. 0.508b kg, respectively) and decreased feed conversion ratio (FCR; 2.09c vs. 1.63b vs. vs. 1.54b vs. 1.54b g/g, respectively) compared to the corn-SBM-based control diet (BWG = 0.593a and FCR = 1.36a). In Experiment 2, diets were formulated with the same amino acid minimums, and as the percentage of PNM increased in the diets (0, 10, 20, and 32%), BWG decreased (0.560a vs. 0.532a vs. 0.521a vs. 0.458b kg, respectively) and FCR increased (1.72b vs. 1.71b vs. 1.79bc vs. 1.86c g/g, respectively). In Experiment 3, addition of Thr to a corn-PNM-based diet increased BWG (-Thr = 0.284c vs. +Thr = 0.397b kg) and decreased FCR (-Thr = 1.60b vs. +Thr = 1.54b g/g). The BWG and FCR were best for the corn-SBM-based control diet (0.499a kg and 1.38a g/g, respectively). In Experiment 4, during the growing period (18 to 42 d), significant interactions occurred between protein source (PNM vs. SBM) and protein level (16 and 20% vs. 24%) for BW and FCR but not for carcass, breast, or leg quarter yield or fat pad weights (P < 0.05) at 42 d of age. Technical (not economic) performance of birds fed PNM was similar to SBM at the highest protein levels fed. PNM could be used as a protein source for broilers under appropriate economic conditions.


Asunto(s)
Alimentación Animal , Arachis , Pollos/fisiología , Proteínas en la Dieta/administración & dosificación , Treonina/administración & dosificación , Aminoácidos/administración & dosificación , Animales , Masculino , Necesidades Nutricionales , Distribución Aleatoria , Glycine max , Aumento de Peso/efectos de los fármacos , Zea mays
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...