RESUMEN
Many doctors take time out of clinical practice, and then have decreased confidence and poor performance ratings on their return. Simulation training provides a safe and effective learning platform for healthcare professionals to become immersed in realistic scenarios that provide an opportunity to develop technical and non-technical skills. A standardised, 1-day, multi-fidelity, interprofessional, simulation training course was developed and delivered at four sites, focusing on human factors, patient safety and acute clinical scenarios relevant for clinicians returning to practice in internal medicine. A total of 56 participants, with a median time out of training of 3.6 years, attended seven courses. Quantitative and qualitative analysis showed a significant pre/post-course increase in candidates' self-reported confidence in returning to practice along with learning in non-technical skills. The carefully designed standardised format may facilitate wider expansion of such training.
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Médicos , Entrenamiento Simulado , Competencia Clínica , Personal de Salud/educación , Humanos , AprendizajeRESUMEN
We report on experiments and modeling on a rotating confined liquid that is forced by circumferential jets coaxial with the rotation axis, wherein system-scale secondary flows are observed to emerge. The jets are evenly divided in number between inlets and outlets and have zero net mass transport. For low forcing strengths the sign of this flow depends on the sign of a sloped end cap, which simulates a planetary ß plane. For increased forcing strengths the secondary flow direction is insensitive to the slope sign, and instead appears to be dominated by an asymmetry in the forcing mechanism, namely, the difference in radial divergence between the inlet and outlet jet profiles. This asymmetry yields a net radial velocity that is affected by the Coriolis force, inducing secondary zonal flow.
RESUMEN
Acute myelogenous leukemia (AML) is a high-risk hematopoietic malignancy caused by a variety of mutations, including genes encoding the cohesin complex. Recent studies have demonstrated that reduction in cohesin complex levels leads to enhanced self-renewal in hematopoietic stem and progenitors (HSPCs). We sought to delineate the molecular mechanisms by which cohesin mutations promote enhanced HSPC self-renewal as this represents a critical initial step during leukemic transformation. We verified that RNAi against the cohesin subunit Rad21 causes enhanced self-renewal of HSPCs in vitro through derepression of polycomb repressive complex 2 (PRC2) target genes, including Hoxa7 and Hoxa9. Importantly, knockdown of either Hoxa7 or Hoxa9 suppressed self-renewal, implying that both are critical downstream effectors of reduced cohesin levels. We further demonstrate that the cohesin and PRC2 complexes interact and are bound in close proximity to Hoxa7 and Hoxa9. Rad21 depletion resulted in decreased levels of H3K27me3 at the Hoxa7 and Hoxa9 promoters, consistent with Rad21 being critical to proper gene silencing by recruiting the PRC2 complex. Our data demonstrates that the cohesin complex regulates PRC2 targeting to silence Hoxa7 and Hoxa9 and negatively regulate self-renewal. Our studies identify a novel epigenetic mechanism underlying leukemogenesis in AML patients with cohesin mutations.
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Autorrenovación de las Células/genética , Represión Epigenética , Regulación de la Expresión Génica , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Neoplasias/genética , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Aneuploidia , Animales , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proliferación Celular , Proteínas Cromosómicas no Histona/química , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , Análisis por Conglomerados , Proteínas de Unión al ADN , Eliminación de Gen , Perfilación de la Expresión Génica , Histonas/metabolismo , Proteínas de Homeodominio/metabolismo , Ratones , Modelos Biológicos , Familia de Multigenes , Complejos Multiproteicos/metabolismo , Células Mieloides/citología , Células Mieloides/metabolismo , Unión Proteica , Dominios y Motivos de Interacción de Proteínas/genética , CohesinasRESUMEN
Skin and soft tissue infections (SSTIs) are common in the era of community-associated methicillin-resistant Staphylococcus aureus (MRSA) among human immunodeficiency virus (HIV)-infected patients, but the risk factors are not well defined. We sought to elucidate the risk factors for SSTI occurrence in an HIV cohort. This investigation was a retrospective, single-center cohort study, carried out during the period 2005-2009. In this cohort of 511 HIV-infected individuals, 133 SSTIs occurred in 87 individuals over 1,228.6 person-years of follow-up, for an incidence of 108 SSTIs/1,000 person-years [95 % confidence interval (CI) 87-135]. The incidence declined significantly over time (p < 0.01). In a multivariable Cox regression, diabetes [hazard ratio (HR) 2.01; 95 % CI 1.04-3.89], psoriasis (HR 5.77; 95 % CI 1.86-17.9), lymphedema (HR 6.84; 95 % CI 2.59-18.1), intravenous catheter presence (HR 3.38; 95 % CI 1.00-11.5), and HIV viral load greater than 1,000 copies/mL (HR 2.13; 95 % CI 1.33-3.41) were most strongly associated with development of the first SSTI. Trends toward an association between SSTI risk and Medicaid insurance (HR 1.67; 95 % CI 0.98-2.83) and sexually transmitted disease during follow-up (HR 1.66; 0.99-2.78) were present. CD4+ count and trimethoprim-sulfamethoxazole use were not associated with SSTI risk. HIV-infected individuals are at high risk for SSTIs. In a primarily urban, African-American cohort, we found that a number of immunologic and demographic factors were associated with SSTI risk.
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Infecciones por VIH/complicaciones , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Infecciones de los Tejidos Blandos/epidemiología , Infecciones Estafilocócicas/epidemiología , Adulto , Antiinfecciosos/uso terapéutico , Recuento de Linfocito CD4 , Estudios de Cohortes , Infecciones Comunitarias Adquiridas , Femenino , Humanos , Estudios Longitudinales , Masculino , Meticilina/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Persona de Mediana Edad , Pacientes Ambulatorios , Estudios Retrospectivos , Factores de Riesgo , Piel/microbiología , Infecciones de los Tejidos Blandos/complicaciones , Infecciones de los Tejidos Blandos/microbiología , Infecciones Estafilocócicas/complicaciones , Infecciones Estafilocócicas/microbiología , Combinación Trimetoprim y Sulfametoxazol/uso terapéuticoRESUMEN
There are no evidence-based interventions to prevent adverse psychosocial consequences after living donation. We conducted a single-site randomized controlled trial to examine the postdonation impact of a preventive intervention utilizing motivational interviewing (MI) to target a major risk factor for poor psychosocial outcomes, residual ambivalence (i.e. lingering hesitation and uncertainty) about donating. Of 184 prospective kidney or liver donors, 131 screened positive for ambivalence; 113 were randomized to (a) the MI intervention, (b) an active comparison condition (health education) or (c) standard care only before donation. Ambivalence was reassessed postintervention (before donation). Primary trial outcomes-psychosocial variables in somatic, psychological and family interpersonal relationship domains-were assessed at 6 weeks and 3 months postdonation. MI subjects showed the greatest decline in ambivalence (p = 0.050). On somatic outcomes, by 3 months postdonation MI subjects reported fewer physical symptoms (p = 0.038), lower rates of fatigue (p = 0.021) and pain (p = 0.016), shorter recovery times (p = 0.041) and fewer unexpected medical problems (p = 0.023). Among psychological and interpersonal outcomes, they had a lower rate of anxiety symptoms (p = 0.046) and fewer unexpected family-related problems (p = 0.045). They did not differ on depression, feelings about donation or family relationship quality. The findings suggest that the intervention merits testing in a larger, multisite trial.
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Consejo , Donadores Vivos/psicología , Trastornos Mentales/prevención & control , Trasplante de Órganos/psicología , Calidad de Vida , Adulto , Estudios de Factibilidad , Femenino , Humanos , Relaciones Interpersonales , Masculino , PronósticoRESUMEN
Cardiothoracic transplant programs generally require that transplant recipients have family caregivers to assist them posttransplant. The burden of caregiving on the family members remains poorly understood. If caregivers' well-being is compromised by caregiving, it may bode poorly for transplant recipients' own health in the long-term posttransplant. We examined caregiver health-related quality of life (HRQOL) during the first year after their family member's transplant, its predictors and its relationship to subsequent patient survival. Adult (aged 18+) caregivers of 242 cardiothoracic transplant recipients (lung = 134; heart = 108) completed assessments of demographics, psychosocial characteristics and caregiver burden at 2 months posttransplant, and HRQOL at 2, 7 and 12 months posttransplant. Recipients' survival time was obtained from medical records. Caregiver HRQOL was generally high across the first-year posttransplant in emotional and social functioning; caregiver physical functioning significantly worsened. There were no differences by type of recipient transplant. Greater caregiver burden predicted poorer caregiver HRQOL in several physical domains at 12 months posttransplant. Transplant recipients whose caregivers had lower perceived general health at 12 months posttransplant showed poorer survival rates during the subsequent 7 years of follow up. Transplant teams should identify those caregivers at risk for poorer general health posttransplant to maximize positive outcomes for the entire family.
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Adaptación Psicológica , Cuidadores/psicología , Trasplante de Corazón/mortalidad , Trasplante de Pulmón/mortalidad , Calidad de Vida , Adulto , Salud de la Familia , Femenino , Humanos , Masculino , Pronóstico , Estudios Prospectivos , Factores de Riesgo , Tasa de SupervivenciaRESUMEN
OBJECTIVE: The morphology of lesions in mouse models of osteoarthritis (OA) has not been comprehensively characterized, in part because current histological assessments of OA focus primarily on articular cartilage (AC). In the present study, sections of murine stifle joints with naturally occurring (aged animals) and surgically induced (destabilized medial meniscus, DMM) OA were examined using a newly developed histological grading scheme that includes quantitative measurements and semiquantitative grades to evaluate multiple joint tissues. DESIGN: The data collected was analyzed using Principal Components Analysis (PCA); factor scores for each joint were generated. Individual parameters and factor scores were compared between surgical groups and among age groups. For comparison, the original Mankin Histological-Histochemical Grading System (HHGS) also was applied. RESULTS: Overall, lesions were most severe in the medial tibial plateaus. Significant changes in AC and neighboring bone were identified in surgically induced models and in naturally occurring disease. Mean factor scores provided a comprehensive evaluation of joint changes. An important new finding was that chondrocyte cell death within the AC was a commonly identified lesion and its extent significantly increased with age. While the Mankin HHGS detected significant overall differences in OA severity between surgical groups, it was not sensitive in detecting age-related differences, nor did it provide information regarding changes in individual tissues. CONCLUSION: These results demonstrate the utility of this newly developed murine OA grading scheme in identifying lesions in AC and in other joint tissues. Surgically induced changes were similar to those occurring naturally with aging.
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Artritis Experimental/patología , Cartílago Articular/patología , Condrocitos/patología , Osteoartritis/patología , Envejecimiento/patología , Animales , Masculino , Meniscos Tibiales/patología , Ratones , Ratones Endogámicos C57BL , Osteoartritis/diagnóstico , Rodilla de Cuadrúpedos/patologíaRESUMEN
Guidelines for the sexual health care of our HIV patients and provision of post-exposure prophylaxis following sexual exposure have been produced by both British Association of Sexual Health & HIV and British HIV Association (BHIVA). In the light of recent criminal prosecutions, BHIVA produced guidance for HIV clinical teams regarding discussions with patients about HIV transmission and reducing the risk to sexual partners. This audit examined the advice given to HIV patients with regard to safer sexual practices, sexually transmitted infection screening and partner notification and found that, on the whole, the standards set by national guidelines were adhered to, although areas for improvement were identified. We hope that the introduction of proformas with specific prompts for these subjects for HIV clinic visits will improve clinical standards in this area.
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Trazado de Contacto , Infecciones por VIH/epidemiología , Auditoría Médica , Conducta Sexual/estadística & datos numéricos , Enfermedades de Transmisión Sexual/epidemiología , Adulto , Femenino , Infecciones por VIH/transmisión , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Sexo Seguro , Enfermedades de Transmisión Sexual/transmisiónRESUMEN
Lactate threshold is an important reference point when setting training intensities for endurance athletes. Ventilatory threshold has been used as a noninvasive estimate of lactate threshold, but appears to underestimate training intensity for many athletes. This study evaluated whether data obtained during a noninvasive, maximal exercise test could be used to predict lactate threshold. Maximal oxygen consumption (55+/-2 ml O(2) x kg(-1) x min(-1)) and heart rate at the ventilatory threshold (V-slope method) were determined for 19 cyclists (10 men, 9 women, 35+/-2 years). Cyclists also performed a lactate threshold test, consisting of 8 min stages at power outputs below, at, and above the ventilatory threshold. Heart rate associated with the lactate threshold was determined using the Dmax method. The correlation coefficient between heart rates at the ventilatory and lactate thresholds was 0.67, indicating 45% shared variance. The best fitting model to predict heart rate at the lactate threshold included heart rate at the ventilatory threshold, gender, body weight, and an interaction between gender and body weight. Using this model, R(2) was 0.70. Thus, heart rate at the ventilatory threshold may be adjusted to more accurately predict a heart rate that corresponds to the lactate threshold for recreational cyclists.
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Umbral Anaerobio/fisiología , Ciclismo/fisiología , Prueba de Esfuerzo , Tolerancia al Ejercicio/fisiología , Ácido Láctico/sangre , Intercambio Gaseoso Pulmonar/fisiología , Adulto , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Consumo de Oxígeno/fisiología , Valor Predictivo de las Pruebas , Análisis de RegresiónRESUMEN
FP3 and 612 viruses are enterovirus-like viruses. Antibody to these viruses is widespread in chicken flocks, but nothing is known about their pathogenicity. Seven experiments were carried out to investigate the tissue tropism and associated pathology of these novel fowl enterovirus-like viruses and to compare these with the effects of the previously studied enterovirus-like viruses, ELV-1 and avian nephritis (ANV). ANV is now classified as an astrovirus. Preliminary experiments were carried out with FP3 virus, 612 virus and ELV-1 to determine the distribution of viral antigen. Each preliminary experiment was followed by a larger experiment that included more birds and in which a greater range of tissues was studied. It was shown that all four viruses studied replicated in the intestine and had differing abilities to spread to other tissues. Histological changes were present in most antigen-positive tissues but they were usually relatively mild. ELV-1 was associated with the most severe intestinal lesions, followed by FP3 virus. FP3 virus produced lesions in the kidney that were marginally more severe than those caused by the G-4260 strain of ANV. FP3 virus also caused pancreatic lesions. The 612 virus was found to be only mildly pathogenic in specific pathogen free chickens.
Asunto(s)
Pollos/virología , Infecciones por Enterovirus/veterinaria , Enterovirus/clasificación , Enterovirus/patogenicidad , Enfermedades Gastrointestinales/veterinaria , Enfermedades de las Aves de Corral/virología , Animales , Antígenos Virales/aislamiento & purificación , Enterovirus/aislamiento & purificación , Infecciones por Enterovirus/virología , Enfermedades Gastrointestinales/patología , Enfermedades Gastrointestinales/virología , Tracto Gastrointestinal/patología , Tracto Gastrointestinal/virología , Riñón/patología , Riñón/virología , Pulmón/virología , Organismos Libres de Patógenos Específicos , Bazo/virologíaRESUMEN
Survival and functional outcomes for lung transplant recipients continue to lag behind those for heart recipients. Whether these poorer physical outcomes translate into poorer quality of life (QOL) for lung recipients relative to heart recipients is unknown. Lung versus heart transplant recipients' perceptions of QOL were longitudinally compared at three time-points across the first year posttransplant. Additionally, potentially important predictors of patient QOL were examined. Adult transplant recipients (N = 199) participated in semi-structured interviews that included measures of QOL, optimism, mastery, social support, religiosity and coping. Temporal patterns of QOL change were compared between lung and heart recipients who survived until 1 year posttransplant using mixed-model, hierarchical analysis of variance (ANOVA). Demographic and psychosocial predictors were examined with multiple regression analysis to identify the unique effects of each variable on QOL 1 year posttransplant. While heart recipients' QOL across several domains was higher shortly after transplant, lung patients' QOL improved and was equivalent to that of heart recipients by 1 year posttransplant. Greater optimism and support from friends predicted better QOL in physical, psychological and social domains. Conversely, avoidant coping strategies predicted poorer physical functioning. Thus, while clinical interventions designed to improve QOL posttransplant should be tailored to transplant recipients' initial psychosocial assets and liabilities, they need not be distinguished by transplant type.
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Supervivencia de Injerto , Trasplante de Corazón , Trasplante de Pulmón , Calidad de Vida , Femenino , Estudios de Seguimiento , Salud , Humanos , Masculino , Persona de Mediana Edad , Calidad de Vida/psicología , Encuestas y Cuestionarios , Factores de Tiempo , Resultado del TratamientoRESUMEN
There have been many reports of the severe clinical disease and pathology seen in young chicks that have been vertically infected with chicken anaemia virus (CAV). The disease is characterized by anaemia, and atrophy of the thymus and bone marrow. However, while it has been suggested that horizontally acquired infections of older birds are common, to date there has been no description in the literature of the pathology of this type of infection. In the present study, 3-week-old and 6-week-old chickens were infected by the oral route, as is likely to occur naturally, and a wide range of tissues were examined immunocytochemically for the presence of CAV antigen. Histological examination was carried out on the thymus, spleen and bone marrow of all birds, and on all other tissue samples in which CAV antigen was found. CAV antigen and associated pathological change were detected in the thymus of both 3-week-old and 6-week-old birds. However, CAV antigen was rarely found in other tissues, which is in contrast to what is found in birds infected when 1-day-old. In particular, very few infected cells were found in the bone marrow. Anaemia and bone marrow atrophy, which are typically found in chicks infected vertically or when 1-day-old, did not develop in the 3-week-old or 6-week-old birds. The findings of this study show that CAV is capable of infecting thymocytes of older birds, in contrast to previous belief, and that it is associated with lymphocyte depletion. There was only limited evidence of viral replication in the other tissues examined.
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Envejecimiento/inmunología , Virus de la Anemia del Pollo/fisiología , Infecciones por Circoviridae/veterinaria , Linfocitos/patología , Timo/inmunología , Timo/virología , Administración Oral , Animales , Pollos , Infecciones por Circoviridae/inmunología , Infecciones por Circoviridae/patología , Recuento de Linfocitos , Linfocitos/inmunología , Organismos Libres de Patógenos Específicos , Timo/patología , Replicación ViralRESUMEN
Although arterial stiffness is an independent cardiovascular risk factor associated with both aging and hypertension, relatively little is known regarding the structural changes in the vessel wall that occur with vessel stiffening. We determined if collagen type-I metabolism is related to arterial stiffening in both hypertensive and normotensive subjects. Arterial stiffness was assessed by aortic pulse wave velocity (PWV) and augmentation index (AIx) in 46 subjects (48.7 +/- 2 years, 32 hypertensives) and related to circulating markers of collagen type-I turnover. Collagen synthesis was assessed by the measurement of carboxy-terminal peptide of procollagen type-I (PIP) and collagen degradation by the measurement of carboxy-terminal telopeptide of collagen type-I (ICTP), by quantitative immunoassay. Matrix metalloproteinase-1 (MMP-1) and the tissue inhibitor of metalloproteinase-1 (TIMP-1) were also quantified by immunoassay. The ratio of collagen type-I synthesis to degradation was negatively correlated with both PWV (P<0.05) and AIx (P<0.05), whereas plasma MMP-1 levels displayed a positive correlation with both PWV (P<0.01) and AIx (P<0.01), after adjustment for age and mean arterial pressure. The relationship between collagen type-I turnover and arterial stiffness was similar in both the normotensive and hypertensive subjects. Although circulating markers of collagen synthesis were increased in the hypertensive subjects, this was not related to arterial stiffness. Collagen type-I degradation is increased in relation to collagen type-I synthesis in subjects with stiffer arteries. Matrix metalloproteinase-1, the enzyme responsible for collagen type-I degradation, is positively related to both large elastic and muscular artery stiffness in normotensive and hypertensive subjects.
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Colágeno Tipo I/metabolismo , Hipertensión/metabolismo , Hipertensión/fisiopatología , Resistencia Vascular , Adulto , Biomarcadores/sangre , Velocidad del Flujo Sanguíneo , Glucemia/metabolismo , Presión Sanguínea , Estudios de Casos y Controles , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Colágeno Tipo I/sangre , Creatinina/sangre , Femenino , Frecuencia Cardíaca , Humanos , Inmunoensayo , Masculino , Metaloproteinasa 1 de la Matriz/sangre , Persona de Mediana Edad , Análisis Multivariante , Fragmentos de Péptidos/sangre , Péptidos/sangre , Procolágeno/sangre , Análisis de Regresión , Inhibidor Tisular de Metaloproteinasa-1/sangre , Triglicéridos/sangreRESUMEN
Defining predictors for insect-transmitted virus (arbovirus) disease cycles requires an understanding of the molecular interactions between the virus and vector insect. Studies of orbiviruses from numerous geographic regions have indicated that virus genes are affected by insect population differences. Therefore, the authors have initiated genetic studies of Culicoides sonorensis, isolating cDNAs for characterisation of differential insect gene expression, as well as a gene discovery project. Previous work identified insect transcripts elevated in orbivirus-infected female midguts at one day post infection (pI). Here, we report cDNAs that were more abundant in midguts two days following an epizootic haemorrhagic disease virus feeding, as well in head/salivary glands at three days pI. Of the cDNAs identified in midguts at two days pI, three encode translational machinery components, and three encode components that affect cellular structural features. Of the differentially expressed salivary gland cDNAs, only one was homologous to a previously identified gene, a putative odorant binding protein.
RESUMEN
1. Administration of aerosolized, radiolabelled Moli1901 (duramycin, 2622U90), a 19 amino acid polycyclic peptide, to rats resulted in the deposition of high amounts of radiolabel in the respiratory tract, with deposited radiolabel persisting almost unchanged through 7 days after dosing. Little to no radiolabel was present in the bloodstream of these rats. 2. Rats absorbed little radiolabel after p.o. administration, with nearly all of the dose excreted in the faeces by 2 days after dosing. 3. At 7 days following an intravenous dose, rats excreted 54% of the radiolabel in faeces and 5.4% in the urine, with 44% remaining in the carcass, primarily in the liver (33%). 4. Following an intratracheal instillation dose to rats, radiolabel was eliminated from the pulmonary system with a half-life of 64 days. Excretion was almost exclusively via faeces, with an elimination half-life of 52 days. Plasma and blood concentrations in these animals were uniformly <1 ng eq. ml(-1) at all sampling times. 5. Results in mice given intravenous and oral doses were consistent with those observed in rats. 6. Prolonged retention of Moli1901 in pulmonary tissue supports its use in the treatment of respiratory diseases.
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Antibacterianos/farmacocinética , Péptidos Cíclicos/farmacocinética , Administración por Inhalación , Administración Oral , Aerosoles , Animales , Antibacterianos/administración & dosificación , Cromatografía Líquida de Alta Presión , Semivida , Intubación Intratraqueal , Masculino , Espectrometría de Masas , Ratones , Péptidos Cíclicos/administración & dosificación , Ratas , Ratas Sprague-Dawley , Radioisótopos de Azufre , Distribución TisularRESUMEN
An attenuated chicken anaemia virus (CAV) isolate, cloned isolate 10, which was molecularly cloned from the Cuxhaven-1 CAV after 173 cell-culture passages, was shown previously to recover pathogenicity following 10 passages in young chicks. The consensus nucleotide sequence of the 'revertant' (Rev) virus, present as a tissue homogenate, differed from cloned isolate 10 at a single nucleotide residue (nucleotide 1739) that changed amino acid 287 of the capsid protein from alanine to aspartic acid. Subjecting Rev virus to 10 cell-culture passages reselected viruses with an alanine at this amino acid position. Experimental infections using a molecularly cloned Rev virus isolate demonstrated that the mutation at nucleotide 1739 was not in itself responsible for the recovery of pathogenicity exhibited by the Rev virus. Additional sequence analyses of cloned amplicons provided evidence that the Rev virus population comprised minor, genetically different subpopulations, and provided an indication of CAV's potential for genetic change.
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Virus de la Anemia del Pollo/patogenicidad , Pollos/virología , Infecciones por Circoviridae/veterinaria , Enfermedades de las Aves de Corral/virología , Animales , Virus de la Anemia del Pollo/aislamiento & purificación , Infecciones por Circoviridae/virología , Regulación Viral de la Expresión Génica , Proteínas Virales/genética , Proteínas Virales/metabolismoRESUMEN
Copper cells were originally identified in Drosophila midgut epithelium by their striking orange fluorescence in copper-fed larvae. Here, we examined copper cell fluorescence in light of the previous observations that (1) a similar fluorescent signal in yeast is produced by a complex between copper and metallothionein, and (2) metallothionein is expressed constitutively in the copper cell region and inducibly in other regions of the Drosophila midgut. Pulse-feeding experiments with 1 mM CuCl2 revealed that fluorescence appeared rapidly in copper cells (<5 min) and slowly in other cells of the midgut (days), suggesting a constitutive cofactor in the former and an inducible cofactor in the latter. Fluorescence was also detected in Drosophila S2 tissue culture cells after induction of metallothionein synthesis by addition of CuCl2 to the growth medium. Thus, fluorescence coincided spatially and temporally with the expression of metallothionein. Fluorescence was also linked to the acid-secreting activity of copper cells. Fluorescence was not observed when acid secretion was inhibited by a mutation in the alpha spectrin gene and acidification was blocked in copper-fed wild-type larvae. However, acidification was restored after a 1-day chase period in which the fluorescent signal became sequestered within a vesicular compartment. We therefore conclude that copper cell fluorescence is most probably attributable to a cytoplasmic copper-metallothionein complex, suggesting an unanticipated role for metallothionein in acid-secreting cells.
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Drosophila/citología , Mucosa Gástrica/metabolismo , Metalotioneína/fisiología , Animales , Células Cultivadas , Cobre/farmacología , Drosophila/embriología , Drosophila/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiología , Fluorescencia , Mucosa Gástrica/citología , Concentración de Iones de Hidrógeno , Cinética , Larva/citología , Metalotioneína/genética , Microscopía Fluorescente , Mutación , Espectrina/genética , Espectrina/fisiologíaRESUMEN
A variant population of chicken anaemia virus (CAV), termed P310 2A9-resist, that resists neutralisation by the monoclonal antibody (MAb) 2A9, was selected from Cux-1 virus that had been passaged 310 times (P310) in MDCC-MSB1 cells. Substantially higher concentrations of MAb 2A9 were required to neutralise the selected virus compared to those required to neutralise a low-passage (P13) Cux-1 isolate. Virus neutralisation tests showed that serum from chickens infected with the P310 2A9-resist virus neutralised P13 virus and that serum from chickens infected with P13 virus conversely neutralised the P310 2A9-resist virus. MDCC-MSB1 cells infected with the P310 2A9-resist virus produced no staining with low dilutions (1:100) of Mab 2A9 in an indirect immunofluorescence (IF) test, whereas cells infected with P13 virus reacted positively at high MAb dilutions (1:80,000). Experimental infections of 1-day-old SPF chicks showed that the P310 2A9-resist virus was substantially attenuated. Chimaeric viruses constructed using PCR-amplified regions from the P310 2A9-resist and a pathogenic low-passage cloned Cux-1 isolate showed that the reduced MAb reactivity and attenuation exhibited by the P310 2A9-resist virus were mainly associated with a region encoding the N-terminal half of the 50 kDa capsid protein VP1 and C-terminal regions of VP2 and VP3. The nucleotide sequence of the protein-coding region of the P310 2A9-resist virus is reported and the amino acid sequences of the 3 encoded proteins compared with those of other Cux-1 isolates.