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Whether targeted therapy (TT) and radiotherapy impact survival after resection of brain metastases (BM) is unknown. The purpose of this study was to analyze the factors affecting overall survival (OS), local control (LC), distant control (DC), and leptomeningeal metastases (LMM) in patients who had undergone resection of BM. We retrospectively analyzed 124 consecutive patients who had undergone resection of BM between 2004 and 2020. Patient information about age, sex, Karnofsky Performance Scale (KPS), origin of cancer, synchronicity, tumor size, status of primary cancer, use of TT, extent of resection, and postoperative radiotherapy was collected. Radiation therapy was categorized into whole-brain radiotherapy (WBRT), localized radiotherapy (local brain radiotherapy or stereotactic radiosurgery (LBRT/SRS)), and no radiation. We identified factors that affect OS, LC, DC, and LMM. In multivariable analysis, significant factors for OS were higher KPS score (≥90) (HR 0.53, p = 0.011), use of TT (HR 0.43, p = 0.001), controlled primary disease (HR 0.63, p = 0.047), and single BM (HR 0.55, p = 0.016). Significant factors for LC were gross total resection (HR 0.29, p = 0.014) and origin of cancer (p = 0.041). Both WBRT and LBRT/SRS showed superior LC than no radiation (HR 0.32, p = 0.034 and HR 0.38, p = 0.018, respectively). Significant factors for DC were use of TT (HR 0.54, p = 0.022) and single BM (HR 0.47, p = 0.004). Reduced incidence of LMM was associated with use of TT (HR 0.42, p = 0.038), synchronicity (HR 0.25, p = 0.028), and controlled primary cancer (HR 0.44, p = 0.047). TT was associated with prolonged OS, improved DC, and reduced LMM in resected BM patients. WBRT and LBRT/SRS showed similar benefits on LC. Considering the extended survival of cancer patients and the long-term effect of WBRT on cognitive function, LBRT/SRS appears to be a good option after resection of BM.
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BACKGROUND: The study aimed to investigate the prognostic factors for patients with brain metastases undergoing radiosurgical treatment and to introduce a simple and practical scoring system for the prediction of survival time. METHODS: We retrospectively analyzed data for 311 patients treated with Gamma Knife radiosurgery at a single institute. The mean age at time of treatment was 60 years (range 23-86 years), and the median Karnofsky performance status (KPS) score was 90 (range 60-100). Using a new prognostic index, the prognostic index for brain metastases (PIBM), the patients were categorized into 3 groups according to the primary tumor status and KPS score. We performed survival analysis and compared the prognostic ability of the PIBM with other published indices. RESULTS: During the median follow-up duration of 8.2 months (range 0.1-109 months), the median overall survival time was 9.1 months. Stable primary tumor status (hazard ratio [HR] 0.497, 95% confidence interval [CI] 0.321-0.769, p = 0.002) and KPS score ≥90 (HR 1.407, 95% CI 1.018-1.946, p = 0.039) significantly predicted longer overall survival. The PIBM showed the lowest Akaike information criterion value and the highest integrated area under the curve value compared with other prognostic indices. CONCLUSIONS: The PIBM may be a more accurate prognostic indicator than other published indices. Although this new and practical prognostic index requires further validation in larger cohort studies, we suggest that the PIBM could be useful to predict survival time and inform appropriate management of patients with brain metastases.
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Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/cirugía , Radiocirugia/métodos , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Clasificación del Tumor/métodos , Pronóstico , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del Tratamiento , Adulto JovenRESUMEN
We investigated the outcomes of gamma knife radiosurgery (GKRS) for elderly patients (≥ 65 years) with brain metastases, and identified survival-associated factors. We retrospectively analyzed data from 115 patients treated with GKRS for 1-15 brain metastases. The median patient age was 72 years; most primary tumors were pulmonary (n = 83). The mean lesion volume was 2.1 ± 4.8 mL. A mean dose of 19.3 Gy was delivered to the mean 63.9% isodose line. The median overall survival (OS) was 5.3 months (95% confidence interval [CI] 3.5-7.1). During follow-up (median, 5.1 months), 91 patients died of primary cancer progression while 1 died of unknown causes. The 6- and 12-month local control rates were 94.9 and 88.1%, respectively. On multivariate analysis, female sex (p = 0.005, hazard ratio [HR] 0.533, 95% CI 0.343-0.827) and a controlled primary tumor (p < 0.001, HR 0.328, 95% CI 0.180-0.596) were significantly favorable prognostic factors. Of non-small cell lung cancer patients with EGFR mutations, 76.5% were women (p = 0.005). The median OS of EGFR-mutant and EGFR-wildtype patients were 19.1 and 4.7 months, respectively (p = 0.080). Brain metastases < 3 mL showed better local control rates after GKRS (p = 0.005). GKRS produces favorable outcomes in women with brain metastases who are ≥ 65 years and have controlled primary tumors. Such patients are therefore suitable candidates for GKRS.
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Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundario , Radiocirugia , Factores de Edad , Anciano , Anciano de 80 o más Años , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/mortalidad , Receptores ErbB/genética , Femenino , Estudios de Seguimiento , Humanos , Masculino , Mutación , Recurrencia Local de Neoplasia , Selección de Paciente , Radiocirugia/efectos adversos , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del Tratamiento , Carga TumoralRESUMEN
BACKGROUND: Although Gamma Knife radiosurgery (GKRS) can provide beneficial therapeutic effects for patients with brain metastases, lesions involving the eloquent areas carry a higher risk of neurologic deterioration after treatment, compared to those located in the non-eloquent areas. We aimed to investigate neurological change of the patients with brain metastases involving the motor cortex (MC) and the relevant factors related to neurological deterioration after GKRS. METHODS: We retrospectively reviewed clinical, radiological and dosimetry data of 51 patients who underwent GKRS for 60 brain metastases involving the MC. Prior to GKRS, motor deficits existed in 26 patients (50.9%). The mean target volume was 3.2 cc (range 0.001-14.1) at the time of GKRS, and the mean prescription dose was 18.6 Gy (range 12-24 Gy). RESULTS: The actuarial median survival time from GKRS was 19.2±5.0 months. The calculated local tumor control rates at 6 and 12 months after GKRS were 89.7% and 77.4%, respectively. During the median clinical follow-up duration of 12.3±2.6 months (range 1-54 months), 18 patients (35.3%) experienced new or worsened neurologic deficits with a median onset time of 2.5±0.5 months (range 0.3-9.7 months) after GKRS. Among various factors, prescription dose (>20 Gy) was a significant factor for the new or worsened neurologic deficits in univariate (p=0.027) and multivariate (p=0.034) analysis. The managements of 18 patients were steroid medication (n=10), boost radiation therapy (n=5), and surgery (n=3), and neurological improvement was achieved in 9 (50.0%). CONCLUSION: In our series, prescription dose (>20 Gy) was significantly related to neurological deterioration after GKRS for brain metastases involving the MC. Therefore, we suggest that careful dose adjustment would be required for lesions involving the MC to avoid neurological deterioration requiring additional treatment in the patients with limited life expectancy.
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OBJECTIVE: The goal of this study was to investigate the treatment results of Gamma Knife radiosurgery (GKRS) for cystic brain metastases and relevant factors associated with local tumor control. MATERIALS AND METHODS: We retrospectively reviewed the clinical, radiological, and dosimetry data of 37 cystic brain metastases of 28 patients who were treated with GKRS. Cyst drainage was performed in 8 large lesions before GKRS to decrease the target volume. The mean target volume was 4.8 (range, 0.3-15.8) cc at the time of GKRS, and the mean prescription dose was 16.6 (range, 13-22) Gy. RESULTS: The actuarial median survival time was 17.7 ± 10.2 months, and the primary tumor status was a significant prognostic factor for survival. The actuarial local tumor control rate at 6 and 12 months was 93.1 and 82.3%, respectively. Among the various factors, only prescription dose (>15 Gy) was a significant factor related to local tumor control after multivariate analysis (p = 0.049). Cyst volume or cyst/total tumor volume ratio did not influence local control after GKRS, when the target volume was reduced to about 15 cc after cyst drainage. CONCLUSION: According to our results, we suggest that stereotactic radiosurgery should be considered as one of the treatment options for cystic brain metastases, when large tumor volume can be reduced by surgical drainage before radiosurgery, especially for patients with a controlled primary tumor.
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Neoplasias Encefálicas/cirugía , Quistes/cirugía , Melanoma/cirugía , Procedimientos Neuroquirúrgicos , Radiocirugia , Adulto , Anciano , Neoplasias Encefálicas/secundario , Femenino , Humanos , Masculino , Melanoma/secundario , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos/métodos , Radiocirugia/métodos , Estudios Retrospectivos , Resultado del Tratamiento , Carga Tumoral/fisiologíaRESUMEN
OBJECTIVE: To study the clinical significance and relevant factors of radiation-induced intratumoral necrosis (RIN) and peritumoral edema (PTE) after Gamma knife radiosurgery (GKRS) for intracranial meningiomas. METHODS: We retrospectively analyzed the data of 64 patients who underwent GKRS for intracranial meningioma. The mean lesion volume was 4.9 cc (range, 0.3-20), and the mean prescription dose of 13.4 Gy (range, 11-18) was delivered to the mean 49.9% (range, 45-50) isodose line. RIN was defined as newly developed or enlarged intratumoral necrosis after GKRS. RESULTS: RIN and new development or aggravation of PTE were observed in 21 (32.8%) and 18 (28.1%) cases of meningioma, respectively during the median follow-up duration of 19.9±1.0 months. Among various factors, maximum dose (>25 Gy) and target volume (>4.5 cc) were significantly related to RIN, and RIN and maximum dose (>24 Gy) were significantly related to the development or aggravation of PTE. In 21 meningiomas with development of RIN after GKRS, there was no significant change of the tumor volume itself between the times of GKRS and RIN. However, the PTE volume increased significantly compared to that at the time of GKRS (p=0.013). The median interval to RIN after GKRS was 6.5±0.4 months and the median interval to new or aggravated PTE was 7.0±0.7 months. CONCLUSION: A close observation is required for meningiomas treated with a maximum dose >24 Gy and showing RIN after GKRS, since following or accompanying PTE may deteriorate neurological conditions especially when the location involves adjacent critical structures.
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To maintain tolerance, autoreactive B cells must regulate signal transduction from the BCR and TLRs. We recently identified that dendritic cells and macrophages regulate autoreactive cells during TLR4 activation by releasing IL-6 and soluble CD40 ligand (sCD40L). These cytokines selectively repress Ab secretion from autoreactive, but not antigenically naive, B cells. How IL-6 and sCD40L repress autoantibody production is unknown. In this work, we show that IL-6 and sCD40L are required for low-affinity/avidity autoreactive B cells to maintain tolerance through a mechanism involving receptor cross-talk between the BCR, TLR4, and the IL-6R or CD40. We show that acute signaling through IL-6R or CD40 integrates with chronic BCR-mediated ERK activation to restrict p-ERK from the nucleus and represses TLR4-induced Blimp-1 and XBP-1 expression. Tolerance is disrupted in 2-12H/MRL/lpr mice where IL-6 and sCD40L fail to spatially restrict p-ERK and fail to repress TLR4-induced Ig secretion. In the case of CD40, acute signaling in B cells from 2-12H/MRL/lpr mice is intact, but the chronic activation of p-ERK emanating from the BCR is attenuated. Re-establishing chronically active ERK through retroviral expression of constitutively active MEK1 restores tolerance upon sCD40L, but not IL-6, stimulation, indicating that regulation by IL-6 requires another signaling effector. These data define the molecular basis for the regulation of low-affinity autoreactive B cells during TLR4 stimulation; they explain how autoreactive but not naive B cells are repressed by IL-6 and sCD40L; and they identify B cell defects in lupus-prone mice that lead to TLR4-induced autoantibody production.
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Autoanticuerpos/biosíntesis , Subgrupos de Linfocitos B/inmunología , Subgrupos de Linfocitos B/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Nefritis Lúpica/metabolismo , Receptor Cross-Talk/inmunología , Receptor Toll-Like 4/fisiología , Animales , Subgrupos de Linfocitos B/patología , Antígenos CD40/metabolismo , Ligando de CD40/metabolismo , Núcleo Celular/enzimología , Núcleo Celular/metabolismo , Células Cultivadas , Técnicas de Cocultivo , Femenino , Tolerancia Inmunológica/genética , Nefritis Lúpica/enzimología , Nefritis Lúpica/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos MRL lpr , Ratones Transgénicos , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/metabolismo , Transporte de Proteínas/genética , Transporte de Proteínas/inmunología , Receptores de Antígenos de Linfocitos B/fisiología , Receptores de Interleucina-6/metabolismo , Transducción de Señal/genética , Transducción de Señal/inmunologíaRESUMEN
The ability to induce Ab responses to pathogens while maintaining the quiescence of autoreactive cells is an important aspect of immune tolerance. During activation of TLR4, dendritic cells (DCs) and macrophages (MFs) repress autoantibody production through their secretion of IL-6 and soluble CD40L (sCD40L). These soluble mediators selectively repress B cells chronically exposed to Ag, but not naive cells, suggesting a means to maintain tolerance during TLR4 stimulation, yet allow immunity. In this study, we identify TNF-α as a third repressive factor, which together with IL-6 and CD40L account for nearly all the repression conferred by DCs and MFs. Similar to IL-6 and sCD40L, TNF-α did not alter B cell proliferation or survival. Instead, it reduced the number of Ab-secreting cells. To address whether the soluble mediators secreted by DCs and MFs functioned in vivo, we generated mice lacking IL-6, CD40L, and TNF-α. Compared to wild-type mice, these mice showed prolonged anti-nuclear Ab responses following TLR4 stimulation. Furthermore, adoptive transfer of autoreactive B cells into chimeric IL-6(-/-) × CD40L(-/-) × TNF-α(-/-) mice showed that preplasma cells secreted autoantibodies independent of germinal center formation or extrafollicular foci. These data indicate that in the absence of genetic predisposition to autoimmunity, loss of endogenous IL-6, CD40L, and TNF-α promotes autoantibody secretion during TLR4 stimulation.
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Autoanticuerpos/biosíntesis , Células Dendríticas/inmunología , Tolerancia Inmunológica , Macrófagos/inmunología , Células Plasmáticas/inmunología , Células Madre/inmunología , Traslado Adoptivo , Animales , Antígenos Nucleares/genética , Antígenos Nucleares/inmunología , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/metabolismo , Ligando de CD40/deficiencia , Células Cultivadas , Células Dendríticas/metabolismo , Tolerancia Inmunológica/genética , Interleucina-6/deficiencia , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos MRL lpr , Ratones Noqueados , Ratones Transgénicos , Células Plasmáticas/metabolismo , Células Plasmáticas/trasplante , Quimera por Radiación/inmunología , Células Madre/metabolismo , Receptor Toll-Like 4/fisiología , Factor de Necrosis Tumoral alfa/deficienciaRESUMEN
OBJECTIVE: The aim of this study is to evaluate the therapeutic effects of gamma knife radiosurgery (GKRS) in patients with multiple brain metastases and to investigate prognostic factors related to treatment outcome. METHODS: We retrospectively reviewed clinico-radiological and dosimetric data of 36 patients with 4-14 brain metastases who underwent GKRS for 264 lesions between August 2008 and April 2011. The most common primary tumor site was the lung (n=22), followed by breast (n=7). At GKRS, the median Karnofsky performance scale score was 90 and the mean tumor volume was 1.2 cc (0.002-12.6). The mean prescription dose of 17.8 Gy was delivered to the mean 61.1% isodose line. Among 264 metastases, 175 lesions were assessed for treatment response by at least one imaging follow-up. RESULTS: The overall median survival after GKRS was 9.1±1.7 months. Among various factors, primary tumor control was a significant prognostic factor (11.1±1.3 months vs. 3.3±2.4 months, p=0.031). The calculated local tumor control rate at 6 and 9 months after GKRS were 87.9% and 84.2%, respectively. Paddick's conformity index (>0.75) was significantly related to local tumor control. The actuarial peritumoral edema reduction rate was 22.4% at 6 months. CONCLUSION: According to our results, GKRS can provide beneficial effect for the patients with multiple (4 or more) brain metastases, when systemic cancer is controlled. And, careful dosimetry is essential for local tumor control. Therefore, GKRS can be considered as one of the treatment modalities for multiple brain metastase.
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BACKGROUND/AIMS: Endoscopic retrograde cholangiopancreatography (ERCP) is the most accurate modality in diagnosis of choledocholithiasis. However, it carries some complications. Endoscopic ultrasonography (EUS) is less invasive than ERCP and used for the diagnosis of choledocholithiasis. Recent studies showed that a usefulness of EUS for the diagnosis of small choledocholithiasis without common bile duct (CBD) dilatation. For such a reason, ERCP is being replaced by EUS in the diagnosis of bile duct stones. The aim of this study was to investigate the accuracy of EUS for the diagnosis of choledocholithiasis without CBD dilatation. METHODS: A total of 66 patients with suspected choledocholithiasis without CBD dilatation were enrolled. EUS were performed in all cases within 48 hours after computed tomography (CT) or ultrasonography (US). Final diagnosis was obtained by ERCP or clinical course (minimum 6 months follow-up). We analyzed the accuracy of US, CT, and EUS, respectively. RESULTS: CT and US were performed in 51 and 15 cases, respectively. CBD stones were detected in 23 (35%) patients by ERCP. EUS showed 100% sensitivity, 95% specificity, 92% positive predictive value, and 100% negative predictive value for identifying CBD stones. CT or US showed 26%, 93%, 67%, and 70%, respectively. There were no EUS-related complications. CONCLUSIONS: EUS was more effective than CT or US and as accurate as ERCP for the diagnosis of small choledocholithiasis without CBD dilatation. Thus, EUS may help to avoid unnecessary diagnostic ERCP and its complication.
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Coledocolitiasis/diagnóstico por imagen , Endosonografía , Adulto , Anciano , Anciano de 80 o más Años , Coledocolitiasis/patología , Enfermedades del Conducto Colédoco/diagnóstico , Diagnóstico Diferencial , Dilatación Patológica/diagnóstico , Femenino , Cálculos Biliares/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: The innate immune response constitutes the first line of defense against invading pathogens and consists of a variety of immune defense mechanisms including active endocytosis by macrophages and granulocytes. Endocytosis can be used as a reliable measure of selective and non-selective mechanisms of antigen uptake in the early phase of an immune response. Numerous assays have been developed to measure this response in a variety of mammalian and fish species. The small size of the zebrafish has prevented the large-scale collection of monocytes/macrophages and granulocytes for these endocytic assays. METHODOLOGY/PRINCIPAL FINDINGS: Pooled zebrafish kidney hematopoietic tissues were used as a source of phagocytic cells for flow-cytometry based endocytic assays. FITC-Dextran, Lucifer Yellow and FITC-Edwardsiella ictaluri were used to evaluate selective and non-selective mechanisms of uptake in zebrafish phagocytes. CONCLUSIONS/SIGNIFICANCE: Zebrafish kidney phagocytes characterized as monocytes/macrophages, neutrophils and lymphocytes utilize macropinocytosis and Ca(2+)-dependant endocytosis mechanisms of antigen uptake. These cells do not appear to utilize a mannose receptor. Heat-killed Edwardsiella ictaluri induces cytoskeletal interactions for internalization in zebrafish kidney monocytes/macrophages and granulocytes. The proposed method is easy to implement and should prove especially useful in immunological, toxicological and epidemiological research.
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Calcio/metabolismo , Endocitosis/fisiología , Riñón/citología , Fagocitos/metabolismo , Pinocitosis , Animales , Antígenos/metabolismo , Edwardsiella ictaluri/metabolismo , Citometría de Flujo , Fluoresceína-5-Isotiocianato , Lectinas Tipo C/metabolismo , Receptor de Manosa , Lectinas de Unión a Manosa/metabolismo , Receptores de Superficie Celular/metabolismo , Pez Cebra/metabolismoRESUMEN
The complete annotation of the cattle genome allows reliable protein identification by tandem mass spectrometry (MS(2)) and greatly facilitates proteomics. Previously, we reported that differential detergent fractionation (DDF) analysis of bovine monocytes reveals proteins related to antigen pattern recognition, uptake and presentation to immunocompetent lymphocytes. Here we have identified 47 bovine proteins, involved in immune function of professional antigen-presenting cells (APC) that have been significantly altered after cytopathic (cp) Bovine Viral Diarrhea Virus (BVDV) infection. In particular, proteins related to immune responses such as cell adhesion, apoptosis, antigen uptake, processing and presentation, acute phase response proteins, MHC class I- and II-related proteins and other molecules involved in immune function of professional antigen presentation have been significantly altered after BVDV infection. Our data suggest that cp BVDV, while promoting monocyte activation and differentiation, is inhibiting their antigen presentation to immunocompetent T cells, thus resulting in the uncontrolled inflammation mediated by activated macrophages, enhanced viral spread, and impaired anti-viral defense mechanisms in the host.
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Presentación de Antígeno/inmunología , Células Presentadoras de Antígenos/inmunología , Diarrea Mucosa Bovina Viral/inmunología , Diarrea Mucosa Bovina Viral/metabolismo , Virus de la Diarrea Viral Bovina/inmunología , Regulación de la Expresión Génica , Monocitos/inmunología , Secuencia de Aminoácidos , Animales , Células Presentadoras de Antígenos/virología , Western Blotting , Diarrea Mucosa Bovina Viral/genética , Bovinos , Virus de la Diarrea Viral Bovina/crecimiento & desarrollo , Virus de la Diarrea Viral Bovina/patogenicidad , Macrófagos/inmunología , Macrófagos/metabolismo , Datos de Secuencia Molecular , Monocitos/metabolismo , Proteómica , Linfocitos T/inmunología , Linfocitos T/metabolismo , Espectrometría de Masas en TándemRESUMEN
Using a proteomics approach, we evaluated the effect of cytopathic (cp), and non-cytopathic (ncp) bovine viral diarrhea viruses (BVDV) on the expression of protein kinases and related proteins in bovine monocytes. Proteins were isolated from membrane and cytosolic fractions with the differential detergent fractionation (DDF) method and identified with 2D-LC ESI MS2. Of approximately 10,000 proteins identified, 378 proteins had homology with known protein kinases or related proteins. Eighteen proteins involved in cell differentiation and activation, migration, anti-viral mechanisms (interferon/apoptosis), biosynthesis, sugar metabolism and oncogenic transformation were significantly altered in BVDV-infected monocytes compared to the uninfected controls. Six proteins, mostly related to cell migration, anti-viral mechanisms, sugar metabolism and possibly tumor resistance were differentially expressed between the ncp and cp BVDV-infected monocytes. Particularly, the expression of the receptor of activated C kinase (RACK), of pyridoxal kinase (PK), diacyglycerol kinase (DGK) and Brutons tyrosine kinase (BTK) was decreased in monocytes infected with cp BVDV compared to ncp BVDV, possibly contributing to the cytopathic effect of the virus. This and other findings are discussed in view of the possible role the identified proteins play in the development of viral infection and oncogenic transformation of cells.
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Virus de la Diarrea Viral Bovina Tipo 1/patogenicidad , Monocitos/enzimología , Monocitos/virología , Proteínas Quinasas/metabolismo , Animales , Diarrea Mucosa Bovina Viral/enzimología , Diarrea Mucosa Bovina Viral/etiología , Diarrea Mucosa Bovina Viral/virología , Bovinos , Cromatografía Liquida , Efecto Citopatogénico Viral , Técnicas In Vitro , Proteínas Quinasas/aislamiento & purificación , Proteínas/aislamiento & purificación , Proteínas/metabolismo , Proteómica , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
Recent data suggest that some of the immunotoxic effects of the herbicide atrazine, a very widely used pesticide, may be due to perturbations in dendritic cell (DC) function. As consequences of atrazine exposure on the phenotypic and functional maturation of DC have not been studied, our objective was, using the murine DC line, JAWSII, to determine whether atrazine will interfere with DC maturation. First, we characterized the maturation of JAWSII cells in vitro by inducing them to mature in the presence of growth factors and selected maturational stimuli in vitro. Next, we exposed the DC cell line to a concentration range of atrazine and examined its effects on phenotypic and functional maturation of DC. Atrazine exposure interfered with the phenotypic and functional maturation of DC at non-cytotoxic concentrations. Among the phenotypic changes caused by atrazine exposure was a dose-dependent removal of surface MHC-I with a significant decrease being observed at 1 microM concentration. In addition, atrazine exposure decreased the expression of the costimulatory molecule CD86 and it downregulated the expression of the CD11b and CD11c accessory molecules and the myeloid developmental marker CD14. When, for comparative purposes, we exposed primary thymic DC to atrazine, MHC-I and CD11c expression was also decreased. Phenotypic changes in JAWSII DC maturation were associated with functional inhibition of maturation as, albeit at higher concentrations, receptor-mediated antigen uptake was increased by atrazine. Thus, our data suggest that atrazine directly targets DC maturation and that toxicants such as atrazine that efficiently remove MHC-I molecules from the DC surface are likely to contribute to immune evasion.