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OBJECTIVE: To evaluate diagnostic and therapeutic practices and then establish a consensus on the management of ocular toxoplasmosis in France through a Delphi study. MATERIALS AND METHODS: Twenty-three French experts in ocular toxoplasmosis were invited to respond to a modified Delphi study conducted online, in the form of two questionnaires, in an attempt to establish a consensus on the diagnosis and management of this pathology. The threshold for identical responses to reach consensus was set at 70 %. RESULTS: The responses of 19 experts out of the 23 selected were obtained on the first questionnaire and 16 experts on the second. The main elements agreed upon by the experts were to treat patients with a decrease in visual acuity or an infectious focus within the posterior pole, to treat peripheral lesions only in the presence of significant inflammation, the prescription of first-line treatment with pyrimethamine-azithromycin, the use of corticosteroid therapy after a period of 24 to 48hours, the prophylaxis of frequent recurrences (more than 2 episodes per year) with trimethoprim-sulfamethoxazole as well as the implementation of prophylactic treatment of recurrences in immunocompromised patients. On the other hand, no consensus emerged with regard to the examinations to be carried out for the etiological diagnosis (anterior chamber paracentesis, fluorescein angiography, serology, etc.), second-line treatment (in the case of failure of first-line treatment), or treatment of peripheral foci. CONCLUSION: This study lays the foundations for possible randomized scientific studies to be conducted to clarify the management of ocular toxoplasmosis, on the one hand to confirm consensual clinical practices and on the other hand to guide practices for which no formal consensus has been demonstrated.
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Toxoplasmosis Ocular , Azitromicina/uso terapéutico , Técnica Delphi , Humanos , Recurrencia , Toxoplasmosis Ocular/diagnóstico , Toxoplasmosis Ocular/epidemiología , Toxoplasmosis Ocular/terapia , Combinación Trimetoprim y Sulfametoxazol/uso terapéuticoRESUMEN
Biostatistics are omnipresent in the scientific and medical literature and are an essential skill for any health student. We have developed a practical training tool - GMRC Shiny stats - an interactive application specifically dedicated to medical data statistical analysis. The application has been designed to provide an analysis workflow corresponding to the usual progression of an experienced statistician during data analysis. The most common statistical analyses can be performed (descriptive statistics, inferences according to frequentist methods, survival analyses, correlation, agreement measurements, etc.). GMRC Shiny stats is intuitive and user-friendly and assists students in choosing the most appropriate statistical tests. With all these functionalities, students can learn statistical analysis by doing. Getting involved in the statistical analysis and processing of their own data is likely to improve their biostatistics skills.
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Bioestadística/métodos , Estadística como Asunto/educación , Curriculum , Humanos , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Investigadores , Facultades de Medicina , Estudiantes de Medicina , Flujo de TrabajoRESUMEN
INTRODUCTION: Multiple system atrophy (MSA) is a neurodegenerative disorder in which vocal fold mobility can be affected, sometimes leading to life-threatening situations. Our aim was to know if laryngeal examination could help differentiate MSA from Parkinson's disease (PD). MATERIALS AND METHODS: Between 2004 to 2014, all consecutive patients diagnosed with probable MSA were included in this retrospective, monocentric study. Flexible laryngoscopy was obtained in 51 MSA patients and compared with 27 patients with Parkinson's disease (PD). Laryngeal muscles EMG was available in 6 MSA patients. RESULTS: Vocal fold motion impairments (VFMI) was found in 35 (68.6%) MSA patients: 15 (29.4%) had uni- or bilateral vocal fold abnormal movement (VFAM), 13 (25.5%) had uni- or bilateral vocal fold abductor paresis (VFABP), 4 (7.8%) had uni- or bilateral vocal fold adductor paresis (VFADP), 10 (19.6%) had bilateral vocal fold paralysis (BVFP). VFMI was found in 13 PD patients (48.1%) all of whom had VFADP. Presence of BVFP was found associated with stridor (P<0.001) and dysphagia (P=0.002). In all muscles examined in 6 MSA patients, the EMG showed neuropathic patterns. CONCLUSIONS: Our data support that VFMI may be encountered in two-thirds of MSA with a variable degree of gravity. Laryngological examination should be considered as a supplementary tool for the diagnosis and prognosis of MSA. VFMI in particular VFAM, VFABD and BVFP should be discussed as an additional possible red flag even at an early stage of MSA and could help discriminate MSA from PD.
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Atrofia de Múltiples Sistemas , Enfermedad de Parkinson , Humanos , Prevalencia , Estudios Retrospectivos , Pliegues VocalesRESUMEN
BACKGROUND: Delayed graft function (DGF) is an early postoperative complication of kidney transplantation (KT) predisposing to acute rejection and lower graft survival. Intraoperative arterial hypotension and hypovolemia are associated with DGF. Central venous pressure (CVP) is used to estimate volemia but its reliability has been criticized. Pleth variability index (PVI) is a hemodynamic parameter predicting fluid responsiveness. The aim of this study was to examine the relationship between intraoperative PVI and CVP values and the occurrence of DGF. METHODS: This was a prospective, noninterventional, observational, single-center study. All consecutive patients with KT from deceased donors were included. Recipients received standard, CVP, and PVI monitoring. Intraoperative hemodynamic parameters were recorded from recipients at 5 time points during KT. RESULTS: Forty patients were enrolled. There was a poor correlation between PVI and CVP values (r2 = 0.003; P = .44). Immediate graft function and DGF patients had similar hemodynamic values during KT, with the exception of PVI values, which were significantly higher in the DGF group. In particular, a PVI >9% before unclamping of the renal artery was the only predictive parameter of DGF in our multivariate analysis (P = .02). CONCLUSIONS: This study suggests that PVI values >9% during KT are associated with the occurrence of DGF.
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Funcionamiento Retardado del Injerto/etiología , Trasplante de Riñón/efectos adversos , Monitoreo Intraoperatorio/estadística & datos numéricos , Adulto , Presión Venosa Central/fisiología , Femenino , Hemodinámica/fisiología , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Intraoperatorio/métodos , Monitoreo Fisiológico/métodos , Monitoreo Fisiológico/estadística & datos numéricos , Pletismografía/métodos , Pletismografía/estadística & datos numéricos , Estudios Prospectivos , Reproducibilidad de los Resultados , Factores de RiesgoRESUMEN
OBJECTIVE: For many physicians, palpable purpura is synonymous with vasculitis. However, a skin biopsy is almost always performed in common clinical practice in order to confirm the diagnosis. The aim of our study was to assess whether palpable purpura is always indicative of an inflammatory infiltrate in a vessel wall. PATIENTS AND METHODS: Eighty-seven patients were included in this prospective monocentric study, 45 of whom were presenting a palpable purpura. Patients were classified in two categories: "leukocytoclastic vasculitis" or "other diagnosis". The clinical and histopathological features of patients with a palpable purpura were studied. RESULTS: The mean age of patients presenting a palpable purpura was 69 years. There were 26 men and 19 women. Of the 43 patients biopsied, 37 were included in the vasculitis group. The sensitivity, specificity, positive predictive value and negative predictive value for a diagnosis of vasculitis in patients with palpable purpura were respectively 82, 65, 86 and 58 %. The Odds ratio was 8.48 (95 % CI, 2.52-31.80; P<0.05). CONCLUSION: Most of the palpable purpuras examined were indeed related to leukocytoclastic vasculitis. In the remaining cases, biopsy did not contribute to the diagnosis since it only showed purpura without vessel wall inflammation. In our opinion, a skin biopsy is thus not essential where the clinical presentation is typical.
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Biopsia , Vasculitis por IgA/diagnóstico , Piel/patología , Vasculitis/diagnóstico , Anciano , Femenino , Humanos , Masculino , Valor Predictivo de las Pruebas , Estudios Prospectivos , Sensibilidad y EspecificidadRESUMEN
AIMS: We report a prospective cohort study of the midterm results of surgical dislocation of the hip (according to Ganz) to perform resection of osteochondromas involving the femoral neck in patients with multiple hereditary exostoses (MHE). METHODS: Hip range of movement (ROM) was assessed pre- and post-operatively. Patients' judgment of post-operative reduction of pain, symptoms, the Rand 36-item Health Survey (RAND-36) and complications were analysed. RESULTS: Symptomatic osteochondromas of the femoral neck were removed in 20 hips (17 patients) between 2007 and 2012. There were nine men and eight women with a mean age at the time of surgery of 29 years (11 to 47). Mean follow-up was 46 months (26 to 73). At latest follow-up, mean ROM was significantly increased in all directions. Post-operatively the pain associated with the lesion was either significantly decreased or non-existent. There was a significant improvement in seven RAND-36 sub-domains. Encountered complications in four patients were pseudoarthrosis of the trochanteric osteotomy, traumatic separation of the trochanteric osteotomy, a pertrochanteric femoral fracture and avasvular necrosis. Histological analysis revealed osteochondromas in all hips. DISCUSSION: This study confirms the Ganz trochanteric flip osteotomy provided a reliable approach to osteochondromas of the femoral neck that are otherwise difficult to access for surgical resection. The procedure offered significant improvement in the quality of life, although one should be aware of the serious complications can arise despite the relatively safe procedure. TAKE HOME MESSAGE: When daily function and activities are affected, resection of osteochondromas of the proximal femur according to Ganz is indicated to significantly improve quality of life.
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Exostosis Múltiple Hereditaria/cirugía , Neoplasias Femorales/cirugía , Osteotomía/métodos , Adolescente , Adulto , Niño , Exostosis Múltiple Hereditaria/fisiopatología , Femenino , Neoplasias Femorales/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/etiología , Estudios Prospectivos , Rango del Movimiento Articular/fisiología , Resultado del Tratamiento , Adulto JovenRESUMEN
OBJECTIVE: The role of gender on long-term infrainguinal open surgery outcomes still remains uncertain in critical limb ischemia patients. The aim of this study is to evaluate the gender-specific differences in patient characteristics and long-term clinical outcomes in terms of survival, primary patency and limb salvage among patients undergoing infrainguinal open surgery for CLI. MATERIAL AND METHODS: All consecutive patients undergoing infrainguinal open surgery for critical limb ischemia between 2003 and 2012 were included. Survival, limb salvage and primary patency rates were assessed. Independent outcome determinants were identified by the Cox proportional hazard ratio using age and gender as adjustment factors. RESULTS: 584 patients (269 women and 315 men, mean age 76 and 71 years respectively) underwent 658 infrainguinal open surgery (313 in women and 345 in men). Survival rate at 6 years was lower among women compared to men with 53.5% vs 70.9% (p < 0.001). The same applied to primary patency (35.9% vs 52.4%, p < 0.001) and limb salvage (54.3% vs 81.1%, p < 0.001) at 6 years. Female-gender was an independent factor predicting death (hazard ratio 1.50), thrombosis (hazard ratio 2.37) and limb loss (hazard ratio 7.05) in age and gender-adjusted analysis. CONCLUSION: Gender-related disparity in critical limb ischemia open surgical revascularization outcomes still remains.
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Disparidades en el Estado de Salud , Isquemia/cirugía , Procedimientos Quirúrgicos Vasculares , Anciano , Anciano de 80 o más Años , Enfermedad Crítica , Femenino , Humanos , Isquemia/diagnóstico , Isquemia/mortalidad , Isquemia/fisiopatología , Recuperación del Miembro , Masculino , Persona de Mediana Edad , Análisis Multivariante , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Factores de Riesgo , Factores Sexuales , Factores de Tiempo , Resultado del Tratamiento , Grado de Desobstrucción Vascular , Procedimientos Quirúrgicos Vasculares/efectos adversos , Procedimientos Quirúrgicos Vasculares/mortalidadRESUMEN
Necroptosis and signaling regulated by RIP1 kinase activity is emerging as a key driver of inflammation in a variety of disease settings. A significant amount has been learned about how RIP1 regulates necrotic cell death through the use of the RIP1 kinase inhibitor Necrostatin-1 (Nec-1). Nec-1 has been a transformational tool for exploring the function of RIP1 kinase activity; however, its utility is somewhat limited by moderate potency, off-target activity against indoleamine-2,3-dioxygenase (IDO), and poor pharmacokinetic properties. These limitations of Nec-1 have driven an effort to identify next-generation tools to study RIP1 function, and have led to the identification of 7-Cl-O-Nec-1 (Nec-1s), which has improved pharmacokinetic properties and lacks IDO inhibitory activity. Here we describe the characterization of GSK'963, a chiral small-molecule inhibitor of RIP1 kinase that is chemically distinct from both Nec-1 and Nec-1s. GSK'963 is significantly more potent than Nec-1 in both biochemical and cellular assays, inhibiting RIP1-dependent cell death with an IC50 of between 1 and 4 nM in human and murine cells. GSK'963 is >10 000-fold selective for RIP1 over 339 other kinases, lacks measurable activity against IDO and has an inactive enantiomer, GSK'962, which can be used to confirm on-target effects. The increased in vitro potency of GSK'963 also translates in vivo, where GSK'963 provides much greater protection from hypothermia at matched doses to Nec-1, in a model of TNF-induced sterile shock. Together, we believe GSK'963 represents a next-generation tool for examining the function of RIP1 in vitro and in vivo, and should help to clarify our current understanding of the role of RIP1 in contributing to disease pathogenesis.
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BACKGROUND: Retinoblastoma is a rare childhood eye cancer caused by germline or somatic mutations in the RB1 gene. Previous studies observed elevated breast cancer risk among retinoblastoma survivors. However, there has been no research on breast cancer risk in relation to radiation (primarily scatter radiation from the primary treatment) and genetic susceptibility of retinoblastoma survivors. METHODS: Two groups of retinoblastoma survivors from the US and UK were selected, and breast cancer risk analysed using a case-control methodology, nesting within the respective cohorts, matching on heritability (that is to say, having bilateral retinoblastoma or being unilateral cases with at least one relative with retinoblastoma), and using exact statistical methods. There were a total of 31 cases and 77 controls. RESULTS: Overall there was no significant variation of breast cancer risk with dose (P>0.5). However, there was a pronounced and significant (P=0.047) increase in the risk of breast cancer with increasing radiation dose for non-heritable retinoblastoma patients and a slight and borderline significant (P=0.072) decrease in risk of breast cancer with increasing radiation dose for heritable retinoblastoma patients, implying significant (P=0.024) heterogeneity in radiation risk between the heritable and non-heritable retinoblastoma groups; this was unaffected by the blindness status. There was no significant effect of any type of alkylating-agent chemotherapy on breast cancer risk (P>0.5). CONCLUSIONS: There is significant radiation-related risk of breast cancer for non-heritable retinoblastoma survivors but no excess risk for heritable retinoblastoma survivors, and no significant risk overall. However, these results are based on very small numbers of cases; therefore, they must be interpreted with caution.
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Neoplasias de la Mama/etiología , Neoplasias del Ojo/radioterapia , Neoplasias Inducidas por Radiación/etiología , Retinoblastoma/radioterapia , Adolescente , Adulto , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/genética , Neoplasias de la Mama Masculina/epidemiología , Neoplasias de la Mama Masculina/etiología , Neoplasias de la Mama Masculina/genética , Estudios de Casos y Controles , Niño , Preescolar , Relación Dosis-Respuesta en la Radiación , Neoplasias del Ojo/genética , Femenino , Genes de Retinoblastoma , Predisposición Genética a la Enfermedad , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Neoplasias Primarias Múltiples/epidemiología , Neoplasias Inducidas por Radiación/epidemiología , Radioterapia/efectos adversos , Retinoblastoma/genética , Estudios Retrospectivos , Riesgo , Tamaño de la Muestra , Método Simple Ciego , Sobrevivientes , Reino Unido/epidemiología , Estados Unidos/epidemiología , Adulto JovenRESUMEN
Current guidelines for air sampling for bacteria and fungi in compounding pharmacies require the use of a medium for each type of organism. U.S. Pharmacopeia (USP) chapter <797> (http://www.pbm.va.gov/linksotherresources/docs/USP797PharmaceuticalCompoundingSterileCompounding.pdf) calls for tryptic soy agar with polysorbate and lecithin (TSApl) for bacteria and malt extract agar (MEA) for fungi. In contrast, the Controlled Environment Testing Association (CETA), the professional organization for individuals who certify hoods and clean rooms, states in its 2012 certification application guide (http://www.cetainternational.org/reference/CAG-009v3.pdf?sid=1267) that a single-plate method is acceptable, implying that it is not always necessary to use an additional medium specifically for fungi. In this study, we reviewed 5.5 years of data from our laboratory to determine the utility of TSApl versus yeast malt extract agar (YMEA) for the isolation of fungi. Our findings, from 2,073 air samples obtained from compounding pharmacies, demonstrated that the YMEA yielded >2.5 times more fungal isolates than TSApl.
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Microbiología del Aire , Bacterias/aislamiento & purificación , Medios de Cultivo/química , Hongos/aislamiento & purificación , Técnicas Microbiológicas/métodos , Farmacias , Sensibilidad y EspecificidadRESUMEN
Both endocrine and non-endocrine cells of the pituitary gland are organized into structural and functional networks which are formed during embryonic development but which may be modified throughout life. Structural mapping of the various endocrine cell types has highlighted the existence of distinct network motifs and relationships with the vasculature which may relate to temporal differences in their output. Functional characterization of the network activity of growth hormone and prolactin cells has revealed a role for cell organization in gene regulation, the plasticity of pituitary hormone output and remarkably the ability to memorize altered demand. As such, the description of these endocrine cell networks alters the concept of the pituitary from a gland which simply responds to external regulation to that of an oscillator which may memorize information and constantly adapt its coordinated networks' responses to the flow of hypothalamic inputs.
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Adenohipófisis/citología , Animales , Comunicación Celular/fisiología , Diferenciación Celular , Corticotrofos/fisiología , Células Endocrinas/fisiología , Femenino , Gonadotrofos/fisiología , Hormona del Crecimiento/metabolismo , Masculino , Ratones , Modelos Biológicos , Adenohipófisis/irrigación sanguínea , Adenohipófisis/embriología , Somatotrofos/fisiología , Células Madre/fisiologíaRESUMEN
UNLABELLED: With the shortage of organ donors, there is a critical need to use all available pancreas grafts for transplantation. METHODS: From June 1994 to December 2006 we performed 340 pancreas transplantations (317 simultaneous pancreas-kidney 5 pancreas only, 18 pancreas after kidney) including 69 (20%) transplantations from donors aged 45 years or older. Pancreas grafts from older donors were analyzed for graft and patient survival as well as surgical complications, compared with results from younger donors. RESULTS: Recipient characteristics were comparable in both groups. The older donor group mean age was 47.8 years (+/-2.1) versus 27.9 years (+/-10.3) for the younger group. Cumulative patient survival was 96% versus 98% after 1, 82% versus 91% after 5 and 82% versus 88% after 10 years with 1-5- and 10-year kidney graft survivals of 82%, 72%, 57% versus 93%, 83%, 73%, respectively. Pancreas transplant survival after 1, 5, and 10 years were 69%, 60%, 45% in older and 88%, 76%, and 72% in younger donor cohorts. There were 14 (20%) cases of venous thrombosis in the older group and 25 (9%) in the younger group (P = .012). CONCLUSION: Our results demonstrated that utilization of pancreas grafts from donors over 45 years resulted in acceptable outcomes after simultaneous pancreas-kidney transplant and could expand the donor pool. Among the older donor group, patient survival was slightly lower than the younger group, whereas pancreas graft function was significantly inferior (P < .01). Since venous thrombosis was the main reason for pancreas graft loss in older group, anticoagulation is essential.
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Trasplante de Riñón/fisiología , Trasplante de Páncreas/fisiología , Donantes de Tejidos/estadística & datos numéricos , Adulto , Factores de Edad , Índice de Masa Corporal , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/cirugía , Nefropatías Diabéticas/cirugía , Femenino , Humanos , Fallo Renal Crónico/cirugía , Trasplante de Riñón/mortalidad , Masculino , Persona de Mediana Edad , Trasplante de Páncreas/mortalidad , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
BACKGROUND: While reports of the use of laryngeal mask airway (LMA)-Classic in great patient numbers are available, data on the use of the laryngeal tube (LT) in this age group is limited. The two devices are compared in a prospective randomized trial to evaluate success rates and quality of airway seal. METHODS: Sixty children, aged 2-8 years, scheduled for elective surgical interventions were randomized to be ventilated with LMA or LT. Standardized anesthesia was induced with fentanyl and propofol. Number of insertion attempts, time until first tidal volume and intraoperative tidal volumes, and peak pressures were recorded. Airway leak pressure was measured with cuff pressure adjusted to 60 cmH(2)O. RESULTS: Demographic data were comparable, average age in the LMA/LT group was 5.2 +/- 1.9/5.3 +/- 1.9 years. Insertion was successful in 29 of 30 patients in the LMA group (second attempt 8) and in all patients in the LT group (second attempt 3). Time until first tidal volume for LMA/LT was 23.1 +/- 7.3/19.2 +/- 8.6 s (P < 0.05). Peak airway pressures for LMA and LT were 15.3 +/- 3.4 and 17.1 +/- 4.0 cmH(2)O (P < 0.05) with tidal volumes of 10.2 +/- 2.2 and 10.2 +/- 1.9 ml.kg(-1), airway leak pressure was 19.2 +/- 8.6 cmH(2)O for LMA and 26.3 +/- 7.3 cmH(2)O for LT (P < 0.001). CONCLUSION: Insertion success rate is high with both LMA and LT in the age group studied. The airway leak pressure, serving as an estimate to judge quality of airway seal, is higher with the LT.
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Anestesia General/instrumentación , Intubación Intratraqueal , Presión del Aire , Niño , Preescolar , Diseño de Equipo , Femenino , Humanos , Intubación Intratraqueal/efectos adversos , Intubación Intratraqueal/instrumentación , Máscaras Laríngeas/efectos adversos , Masculino , Monitoreo Fisiológico , Evaluación de Resultado en la Atención de Salud , Estudios ProspectivosRESUMEN
An enzyme-linked immunosorbent assay (ELISA) for Lawsonia intracellularis was developed and compared with a whole-cell antigen-based immunofluorescence antibody test (IFAT). The antigen-containing lipopolysaccharide (LPS) was derived from Percoll gradient purified cultures of L. intracellularis by using a modification of the Westphal hot phenol procedure. The antigen was bound directly to polystyrene 96-well microtiter plates, and the assay was performed in an indirect ELISA format. Specificity and sensitivity values based on 80 known positive and 80 known negative serum samples from controlled experimental trials were 93.7% and 88.7%, respectively. Serological results from a controlled L. intracellularis challenge exposure study confirmed the high specificity and sensitivity of this assay (100% and 99.5%, respectively). Comparisons between the LPS ELISA and the IFAT in detecting anti-Lawsonia antibodies in this controlled study revealed significantly more LPS ELISA-positive pigs than IFAT-positive pigs on days 21, 28, 35, and 42 (P = 0.003, 0.030, 0.002, and 0.006, respectively). This indirect ELISA (LPS ELISA) test is an improved method of detecting antibodies in pigs soon after exposure to L. intracellularis, regardless of isolate type (vaccine or wild type) in experimental studies. The LPS ELISA may be used as a tool to support future research trials on vaccine efficacy and to further understand the immune response induced by L. intracellularis.
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Infecciones por Desulfovibrionaceae/diagnóstico , Ensayo de Inmunoadsorción Enzimática/métodos , Lawsonia (Bacteria)/inmunología , Lipopolisacáridos/inmunología , Enfermedades de los Porcinos/diagnóstico , Animales , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/inmunología , Infecciones por Desulfovibrionaceae/inmunología , Infecciones por Desulfovibrionaceae/veterinaria , Ensayo de Inmunoadsorción Enzimática/veterinaria , Técnica del Anticuerpo Fluorescente Indirecta , Inmunización , Enfermedades Intestinales/diagnóstico , Enfermedades Intestinales/inmunología , Enfermedades Intestinales/veterinaria , Porcinos , Enfermedades de los Porcinos/inmunología , Enfermedades de los Porcinos/microbiologíaRESUMEN
Tuberculosis remains a global health problem, and programs dedicated to discovery of novel compounds against Mycobacterium tuberculosis require robust assays for high-throughput screening of chemical and natural product libraries. Enzymes involved in the biosynthesis of mycolic acids, vital components of the mycobacterial cell wall, have received much attention as potential drug targets. KasA and KasB, examples of the beta-ketoacyl-acyl carrier protein synthase I/II (KASI/II) class of condensing enzymes of the M. tuberculosis fatty acid synthase II system have been the focus of several studies designed to biochemically characterize these enzymes. Whilst robust methods have been developed for FabH-like proteins, fast and sensitive assays for high-throughput screening of KASI/II enzymes have not been available. Here we report the development of a direct scintillation proximity assay (SPA) for the KASI/II enzymes, KasA and KasB. The SPA was more sensitive than existing assays, as shown by its ability to measure activity using less enzyme than other assay formats, and the SPA was validated using the known KAS inhibitor thiolactomycin. In addition, the KasA and KasB SPA was adapted for use with Staphylococcus aureus FabF to show the versatility of this assay format to KAS enzymes from other pathogenic organisms.
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3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/metabolismo , Mycobacterium tuberculosis/enzimología , Ácidos Micólicos/metabolismo , Oxidorreductasas/metabolismo , Antibacterianos/farmacología , Técnicas de Química Analítica/métodos , Dimetilsulfóxido/farmacología , Enoil-ACP Reductasa (NADPH Específica B) , Inhibidores Enzimáticos/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Staphylococcus aureus , Tiofenos/farmacología , Factores de TiempoRESUMEN
We cloned the gene and cDNA for rat bombesin receptor subtype-3 (BRS-3) and characterized its mRNA expression pattern and pharmacological properties. Despite the high degree of sequence similarity (80% identical), rat and human BRS-3 differ markedly in their pharmacological properties. Although the natural ligand for BRS-3 is still unknown, a synthetic peptide, dY-Q-W-A-V-(beta-A)-H-F-Nle-amide (dY-bombesin), activates human BRS-3 with an EC(50) of 1.2 nM. In contrast, dY-bombesin had a very poor potency for rat BRS-3 (EC(50) = 2 microM). To understand the molecular basis of this pharmacological difference, we constructed chimeric receptors in which individual extracellular loops of rat BRS-3 were replaced with the corresponding human sequences. Switching the N-terminal region or the second extracellular loop did not significantly change receptor properties. However, switching the third extracellular loop (E3) in the rat BRS-3 resulted in a chimeric receptor (RB3-E3) that behaved almost identically to human BRS-3. RB3-E3 bound dY-bombesin with high affinity (K(i) = 1.2 +/- 0.7 nM), and was activated by dY-bombesin with high potency (EC(50) = 1.8 +/- 0.5 nM). Within the E3 loop, mutation of Y(298)E(299)S(300) to S(298)Q(299)T(300) (RB3-SQT) or of D(306)V(307)P(308) to A(306)M(307)H(308) (RB3-AMH) only partially mimicked the effect of switching the entire E3 loop, and mutation of A(302)E(303) to V(302)D(303) or of V(310)V(311) to I(310)F(311) had little effect on the dY-bombesin potency. These results indicate that the sequence variation in the E3 loop is responsible for the species difference between rat and human BRS-3, and multiple residues in the E3 loop are involved in interactions with the agonist dY-bombesin.
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Receptores de Bombesina/química , Receptores de Bombesina/fisiología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Bombesina/farmacología , Clonación Molecular , Cartilla de ADN , Humanos , Ratones , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Ratas , Receptores de Bombesina/efectos de los fármacos , Receptores de Bombesina/genética , Mapeo Restrictivo , Alineación de Secuencia , Homología de Secuencia de AminoácidoRESUMEN
Interleukin-6 (IL-6) induces the activation of the Src family kinase Hck, which is associated with the IL-6 receptor beta-chain, gp130. Here we describe the identification of an "acidic" domain comprising amino acids 771 to 811 of gp130 as a binding region for Hck, which mediates proliferative signaling. The deletion of this region of gp130 (i.e., in deletion mutant d771-811) resulted in a significant reduction of Hck kinase activity and cell proliferation upon stimulation of gp130 compared to wild-type gp130. In addition, d771-811 disrupted the growth factor-stimulated activation of Erk and the dephosphorylation of Pyk2. Based on these findings, we propose a novel, acidic domain of gp130, which is responsible for the activation of Hck, Erk, and Pyk2 and signals cell proliferation upon growth factor stimulation.
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Antígenos CD/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Transducción de Señal/fisiología , Secuencias de Aminoácidos/fisiología , Animales , Antígenos CD/genética , División Celular/efectos de los fármacos , División Celular/fisiología , Línea Celular , Receptor gp130 de Citocinas , Proteínas de Unión al ADN/metabolismo , Activación Enzimática/efectos de los fármacos , Activación Enzimática/fisiología , Inhibidores Enzimáticos/farmacología , Quinasa 2 de Adhesión Focal , Sustancias de Crecimiento/farmacología , Humanos , Interleucina-6/metabolismo , Interleucina-6/farmacología , Glicoproteínas de Membrana/genética , Ratones , Mutagénesis Sitio-Dirigida , Unión Proteica/efectos de los fármacos , Unión Proteica/fisiología , Estructura Terciaria de Proteína/fisiología , Proteínas Proto-Oncogénicas c-hck , Receptores de Eritropoyetina/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Factor de Transcripción STAT3 , Transducción de Señal/efectos de los fármacos , Transactivadores/metabolismo , TransfecciónRESUMEN
Mycolic acids are vital components of the Mycobacterium tuberculosis cell wall, and enzymes involved in their formation represent attractive targets for the discovery of novel anti-tuberculosis agents. Biosynthesis of the fatty acyl chains of mycolic acids involves two fatty acid synthetic systems, the multifunctional polypeptide fatty acid synthase I (FASI), which performs de novo fatty acid synthesis, and the dissociated FASII system, which consists of monofunctional enzymes, and acyl carrier protein (ACP) and elongates FASI products to long chain mycolic acid precursors. In this study, we present the initial characterization of purified KasA and KasB, two beta-ketoacyl-ACP synthase (KAS) enzymes of the M. tuberculosis FASII system. KasA and KasB were expressed in E. coli and purified by affinity chromatography. Both enzymes showed activity typical of bacterial KASs, condensing an acyl-ACP with malonyl-ACP. Consistent with the proposed role of FASII in mycolic acid synthesis, analysis of various acyl-ACP substrates indicated KasA and KasB had higher specificity for long chain acyl-ACPs containing at least 16 carbons. Activity of KasA and KasB increased with use of M. tuberculosis AcpM, suggesting that structural differences between AcpM and E. coli ACP may affect their recognition by the enzymes. Both enzymes were sensitive to KAS inhibitors cerulenin and thiolactomycin. These results represent important steps in characterizing KasA and KasB as targets for antimycobacterial drug discovery.