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Preoperative portal vein embolization is a beneficial option to reduce the risk of postoperative liver failure by promoting the growth of the future liver remnant. In particular, a percutaneous transhepatic procedure (percutaneous transhepatic portal vein embolization) has been developed as a less-invasive approach. Although percutaneous transhepatic portal vein embolization is widely recognized as a safe procedure, various complications, including rare but fatal adverse events, have been reported. Currently, there are no prospective clinical trials regarding percutaneous transhepatic portal vein embolization procedures and no standard guidelines for the PTPE procedure in Japan. As a result, various methods and various embolic materials are used in each hospital according to each physician's policy. The purpose of these guidelines is to propose appropriate techniques at present and to identify issues that should be addressed in the future for safer and more reliable percutaneous transhepatic portal vein embolization techniques.
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It is recommended that patients with childhood-onset chronic diseases (CCD) be transferred from pediatric to adult healthcare systems when they reach adulthood. Transitional support helps adolescents with CCD transition smoothly. Transition readiness is one of the key concepts to assess the efficacy of transitional support programs. This study aims to investigate the effect of a transitional support program on transition readiness, self-esteem, and independent consciousness among Japanese adolescents with various CCD using a randomized controlled trial. Adolescents with CCD aged 12-18 years participated in a randomized controlled trial evaluating the efficacy of a transitional support program. The patients in the intervention group visited transitional support outpatient clinics twice. They answered questionnaires regarding their disease and future perspectives to healthcare professionals and independently made a short summary of their disease. All the participants answered the questionnaires four times. Eighty patients participated in this study. Among those in the intervention group, transition readiness within one, three, and 6 months after interventions, and self-esteem within 1 month after interventions were higher than that of the control group. The scores on the "dependence on parents" subscale at 6 months after interventions were lower for the intervention group as compared to the control group. This program is expected to help patients transition smoothly from pediatric to adult healthcare systems.
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Viral spike proteins play important roles in the viral entry process, facilitating attachment to cellular receptors and fusion of the viral envelope with the cell membrane. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein binds to the cellular receptor angiotensin converting enzyme-2 (ACE2) via its receptor-binding domain (RBD). The cysteine residue at position 488, consisting of a disulfide bridge with cysteine 480 is located in an important structural loop at ACE2-binding surface of RBD, and is highly conserved among SARS-related coronaviruses. We showed that the substitution of Cys-488 with alanine impaired pseudotyped SARS-CoV-2 infection, syncytium formation, and cell-cell fusion triggered by SARS-CoV-2 spike expression. Consistently, in vitro binding of RBD and ACE2, spike-mediated cell-cell fusion, and pseudotyped viral infection of VeroE6/TMPRSS2 cells were inhibited by the thiol-reactive compounds N-acetylcysteine (NAC) and a reduced form of glutathione (GSH). Furthermore, we demonstrated that the activity of variant spikes from the SARS-CoV-2 alpha and delta strains were also suppressed by NAC and GSH. Taken together, these data indicate that Cys-488 in spike RBD is required for SARS-CoV-2 spike functions and infectivity, and could be a target of anti-SARS-CoV-2 therapeutics.
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BACKGROUND: The evaluation of transition readiness is indispensable for long-term follow-ups of adolescent patients with childhood-onset chronic diseases (CCD). We developed a Japanese version of the TRANSITION-Q (TRANSITION-Q-J) and used it to assess Japanese patients with CCD. METHODS: The TRANSITION-Q-J was developed through forward and backward translations followed by cognitive interviews with five adolescent patients. The field test was conducted with 125 adolescent patients, and a retest was conducted with 113 adolescent patients. RESULTS: Confirmatory factor analysis supported the two-factor analysis model including F1 (communication and self-management) and F2 (examination behavior). Sufficient internal consistency and test-retest reliability were demonstrated among the total 14 items, F1, and F2 (Cronbach's α > 0.80, intraclass correlation coefficient > 0.85). Convergent and discriminant validity for the 14 items and F1 were acceptable; however, F2 did not correlate significantly with the Rosenberg Self-Esteem Scale and Independent Consciousness Scale. Regarding known-groups validity, the older group had a significantly higher mean TRANSITION-Q-J score (50.05) than the younger group (43.28; P = 0.04). The same results were found for both F1 and F2. CONCLUSIONS: The TRANSITION-Q-J for adolescent patients with CCD was developed and its reliability and validity were verified. This scale is easy to administer. In addition to being a tool for transition period support, it could be used to verify effective factors and in program outcome evaluation, including intervention studies.
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Traducciones , Adolescente , Niño , Análisis Factorial , Humanos , Japón , Psicometría , Reproducibilidad de los Resultados , Encuestas y CuestionariosRESUMEN
We have found that the number of packages influences contrast for brain tissue signals on fluid-attenuated inversion recovery (FLAIR). The purpose of this study was to evaluate the contrast of white and gray matters by changing the number of packages. In a volunteer study (n=8), FLAIR images were obtained with the various number of packages (number of package=2, 3, 4, 5). We investigated the same imaging condition at both 1.5 and 3.0T. The signal intensity of white and gray matters in all volunteers was increased as increasing the number of packages. Moreover, the contrast ratio between white and gray matters was slightly decreased. In our conclusion, the contrast between the gray and white matters on FLAIR was influenced by the number of packages.
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Encéfalo , Imagen por Resonancia Magnética , Encéfalo/diagnóstico por imagen , Sustancia Gris/diagnóstico por imagen , Humanos , Sustancia Blanca/diagnóstico por imagenRESUMEN
Immunodeficient mice engrafted with human peripheral blood cells are promising tools for in vivo analysis of human patient individual immune responses. However, when human peripheral blood mononuclear cells (PBMCs) are transferred into NOG (NOD/Shi-scid, IL-2rgnull) mice, severe graft versus host disease (GVHD) hinders long term detailed analysis. Administration of human PBMCs into newly developed murine MHC class I- and class II-deficient NOG (NOG-dKO; NOG- Iab, B2m-double-knockout) mice showed sufficient engraftment of human immune cells with little sign of GVHD. Immunization with influenza vaccine resulted in an increase in influenza-specific human IgG Ab, indicating induction of antigen-specific B cells in the NOG-dKO mice. Immunization with human dendritic cells pulsed with HLA-A2 restricted cytomegalovirus peptide induced specific cytotoxic T cells, indicating the induction of antigen-specific T cells in the NOG-dKO mice. Adoptive cell therapies (ACTs) using melanoma antigen recognized by T cells (MART-1)-specific TCR-transduced activated T cells showed strong tumor growth inhibition in NOG-dKO mice without any sign of GVHD accompanied by preferential expansion of the transferred MART-1-specific T cells. ACTs using cultured human melanoma infiltrating T cells also showed anti-tumor effects against autologous melanoma cells in NOG-dKO mice, in which changes in human cancer phenotypes by immune intervention, such as increased CD271 expression, could be evaluated. Therefore, NOG-dKO mice are useful tools for more detailed analysis of both the induction and effector phases of T-cell and B-cell responses for a longer period than regular NOG mice.
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Antígenos de Histocompatibilidad Clase II/inmunología , Antígenos de Histocompatibilidad Clase I/inmunología , Leucocitos Mononucleares , Modelos Inmunológicos , Traslado Adoptivo , Animales , Xenoinjertos , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase II/genética , Humanos , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/trasplante , Antígeno MART-1/genética , Antígeno MART-1/inmunología , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCIDRESUMEN
To improve current cancer immunotherapies, strategies to modulate various immunosuppressive cells including myeloid derived suppressor cells (MDSC) which were shown to be negative factors in immune-checkpoint blockade therapy, need to be developed. In the present study, we evaluated the role of the local renin-angiotensin system (RAS) in the tumor immune-microenvironment using murine models bearing tumor cell lines in which RAS was not involved in their proliferation and angiogenetic ability. Giving angiotensin II receptor blockers (ARB) to C57BL/6 mice bearing murine colon cancer cell line MC38 resulted in significant enhancement of tumor antigen gp70 specific T cells. ARB administration did not change the numbers of CD11b+ myeloid cells in tumors, but significantly reduced their T-cell inhibitory ability along with decreased production of various immunosuppressive factors including interleukin (IL)-6, IL-10, vascular endothelial growth factor (VEGF), and arginase by CD11b+ cells in tumors. ARB also decreased expression of immunosuppressive factors such as chemokine ligand 12 and nitric oxide synthase 2 in cancer-associated fibroblasts (CAF). Last, combination of ARB and anti-programmed death-ligand 1 (PD-L1) antibodies resulted in significant augmentation of anti-tumor effects in a CD8+ T cell-dependent way. These results showed that RAS is involved in the generation of an immunosuppressive tumor microenvironment caused by myeloid cells and fibroblasts, other than the previously shown proliferative and angiogenetic properties of cancer cells and macrophages, and that ARB can transform the immunosuppressive properties of MDSC and CAF and could be used in combination with PD-1/PD-L1 immune-checkpoint blockade therapy.
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Antagonistas de Receptores de Angiotensina/administración & dosificación , Neoplasias del Colon/tratamiento farmacológico , Sistema Renina-Angiotensina/efectos de los fármacos , Microambiente Tumoral/efectos de los fármacos , Antagonistas de Receptores de Angiotensina/farmacología , Animales , Antígenos de Neoplasias/inmunología , Fibroblastos Asociados al Cáncer/efectos de los fármacos , Fibroblastos Asociados al Cáncer/inmunología , Línea Celular Tumoral , Neoplasias del Colon/inmunología , Neoplasias del Colon/metabolismo , Humanos , Ratones , Ratones Endogámicos C57BL , Trasplante de Neoplasias , Óxido NítricoRESUMEN
Cyclophilin D is a peptidyl-prolyl cis-trans isomerase localized in the mitochondrial matrix. Although its effects on mitochondrial characteristics have been well studied, its relation to the uptake of molecules by mitochondria remains unknown. Here, we demonstrated the effects of cyclophilin D on the intracellular translocation of calcein AM. Following addition of calcein AM to control cells or cells overexpressing wild-type cyclophilin D, calcein fluorescence was observed in mitochondria. However, long-term inhibition of cyclophilin D in these cells altered the localization of calcein fluorescence from mitochondria to lysosomes without changing mitochondrial esterase activity. In addition, depletion of glucose from the medium recovered calcein localization from lysosomes to mitochondria. This is the first demonstration of the effects of cyclophilin D on the intracellular translocation of molecules other than proteins and suggests that cyclophilin D may modify mitochondrial features by inducing the translocation of molecules to the mitochondria through the mechanism associated with cellular energy metabolism.
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Ciclofilinas/antagonistas & inhibidores , Fluoresceínas/química , Lisosomas/metabolismo , Mitocondrias/metabolismo , Animales , Línea Celular , Peptidil-Prolil Isomerasa F , Ciclofilinas/metabolismo , Glucosa/química , Células HeLa , Humanos , Microscopía Fluorescente , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Transporte de Proteínas , Ratas , cis-trans-Isomerasas/metabolismoRESUMEN
Purpose. Meibomian gland dysfunction (MGD) can lead to abnormalities in the composition and function of tear film, resulting in dry eye. Eyelid hygiene is a key to management of MGD. We tested a novel eyelid shampoo (Eye Shampoo Long, ESL) for its ability to maintain lid hygiene. This shampoo is nonirritating and can potentially lengthen eyelashes. This study was aimed to evaluate the efficacy of ESL in the treatment of MGD and its effects on eyelash length. Methods. Ten patients with MGD and 10 healthy subjects without MGD applied ESL twice daily for 8 weeks. Patients were examined for lid margin and dry eye before and after the trial. Subjective symptoms were evaluated. Eyelash length was measured at baseline and at the end of the trial. Results. In the MGD group, significant improvements were observed in subjective symptoms obstruction of the meibomian orifice, secretion of meibum, eyelashes contamination, eyelid margin foam, and SPK. Eyelash length became significantly longer. Conclusions. Maintaining eyelid hygiene using ESL improved the eyelid margins and symptoms of dry eye in MGD patients and increased eyelash length. These findings are promising and warrant confirmation in a larger randomized controlled study.
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Terrestrial mollusks can form an odor aversion memory following the simultaneous presentation of a food odor and an aversive stimulus. The local field potential oscillation recorded on the surface of the procerebrum (PC; the higher olfactory center) exhibits a frequency change in response to the detection of a learned odor; such a change is thus considered to reflect the internal state of the brain during memory recall. Thus far, dopamine and serotonin have been demonstrated to change the oscillatory frequency. Other monoamines, however, have not yet been studied. In the present study, we investigated the possible involvement of histamine (HA). Immunohistochemical staining of HA and in situ hybridization against histidine decarboxylase revealed the location of the cell bodies of HAergic neurons in all ganglia of the brain. The majority of them were located at the medial aspect of the pedal ganglia, and the cerebral ganglia also contained numerous HAergic neurons in their posterior regions. The neuropil layers of the PC received HAergic innervation from the neurons in the cerebral ganglion, as well as from a few neurons located in the dorsomedial part of the cell mass layer of the PC. The HAergic fibers, however, innervated spatially limited regions of the PC, and seemed to affect a small fraction of the PC neurons. HA exerted accelerating effects on the LFP oscillation in a dose-dependent manner, and this effect was suppressed by an H2 blocker, cimetidine. Our results support the involvement of HA in the functioning of the PC.
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Gastrópodos/citología , Gastrópodos/fisiología , Histamina/metabolismo , Neuronas/citología , Neuronas/fisiología , Olfato/fisiología , Secuencia de Aminoácidos , Animales , Biotina/análogos & derivados , Biotina/metabolismo , Calcio/metabolismo , Ganglios de Invertebrados/citología , Ganglios de Invertebrados/fisiología , Gastrópodos/efectos de los fármacos , Histidina Descarboxilasa/genética , Histidina Descarboxilasa/metabolismo , Inmunohistoquímica , Hibridación in Situ , Potenciales de la Membrana/efectos de los fármacos , Datos de Secuencia Molecular , Neuronas/efectos de los fármacos , Técnicas de Placa-Clamp , Periodicidad , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Homología de Secuencia de Aminoácido , Olfato/efectos de los fármacos , Imagen de Colorante Sensible al VoltajeRESUMEN
To study the usefulness of chitosan laurate (CS-LA), a newly developed chitosan salt, as a lubricant, lubrication properties such as the pressure transmission ratio and ejection force were determined at different concentrations of CS-LA in tableting. In addition, tablet properties such as the tensile strength, disintegration time, and dissolution behavior, were also determined. When CS-LA was mixed at concentrations of 0.1%-3.0%, the pressure transmission ratio was increased in a concentration-dependent manner, and the value at a CS-LA concentration of 3% was equal to that of magnesium stearate (Mg-St), a widely used lubricant. Additionally, a reduction in the ejection force was observed at a concentration from 1%, proving that CS-LA has good lubrication performance. A prolonged disintegration time and decreased tensile strength, which are known disadvantages of Mg-St, were not observed with CS-LA. Furthermore, with CS-LA, retardation of dissolution of the drug from the tablets was not observed. Conjugation of CS with LA was found to be quite important for both lubricant and tablet properties. In conclusion, CS-LA should be useful as an alternative lubricant to Mg-St.
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Acetaminofén/química , Quitosano/química , Lubricantes/química , Quitosano/análogos & derivados , Tamaño de la Partícula , Propiedades de Superficie , Comprimidos/químicaRESUMEN
UNLABELLED: Lymph node metastasis is the major clinicopathologic feature associated with poor prognosis in patients with head and neck squamous cell carcinoma (HNSCC). Here, web-based bioinformatics meta-analysis was performed to elucidate the molecular mechanism of lymph node metastasis of human HNSCC. Preferential upregulation of Myosin 1b (MYO1B) transcript in HNSCC datasets was identified. Myo1b mRNA was highly expressed in human HNSCC cells and patient tissue specimens compared with their normal counterparts as shown by quantitative PCR (qPCR) analyses. Immunohistochemistry (IHC)-detected Myo1b expression was significantly correlated with lymph node metastases in patients with oral cancer of the tongue. HNSCC with high expression of Myo1b and chemokine receptor 4 (CCR4), another metastasis-associated molecule, was strongly associated with lymph node metastasis. RNA interference (RNAi) of Myo1b in HNSCC cells, SAS and HSC4, significantly inhibited migratory and invasive abilities through decreased large protrusion formation of cell membranes. Finally, Myo1b knockdown in SAS cells significantly inhibited in vivo cervical lymph node metastases in a cervical lymph node metastatic mouse model system. IMPLICATIONS: Myo1b is functionally involved in lymph node metastasis of human HNSCC through enhanced cancer cell motility and is an attractive target for new diagnostic and therapeutic strategies for patients with HNSCC.
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Carcinoma de Células Escamosas/patología , Neoplasias de Cabeza y Cuello/patología , Ganglios Linfáticos/patología , Miosina Tipo I/genética , Miosina Tipo I/metabolismo , Neoplasias de la Lengua/patología , Anciano , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Simulación por Computador , Bases de Datos Genéticas , Femenino , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/metabolismo , Humanos , Ganglios Linfáticos/metabolismo , Metástasis Linfática , Masculino , Receptores CCR4/genética , Receptores CCR4/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello , Neoplasias de la Lengua/genética , Neoplasias de la Lengua/metabolismo , Regulación hacia ArribaRESUMEN
In cancer patients, sentinel lymph nodes (SLNs) are crucial in the induction of antitumor T cells. However, in many cases, SLNs and tumors appear to be in immunosuppressive condition through mechanisms yet to be elucidated. In this study, the role of tumor-derived TGF-ß1 in the generation of immunosuppressive microenvironments of tumors and SLNs was investigated. Murine colorectal carcinoma CT26 transduced with TGF-ß1 cDNA (CT26-TGF-ß1) showed enhanced tumor growth compared with mock-transduced CT26 (CT26-Mock) when implanted in syngeneic Balb/c mice, even though CT26-TGF-ß1 shows slower growth in vitro. This enhanced growth was not observed when implanted in immunodeficient mice, suggesting that TGF-ß1 enhanced tumor growth by suppressing antitumor T-cell responses. Analysis of immune cells in CT26-TGF-ß1-implanted mice revealed impairment of dendritic cells (DCs), decrease of CD8 T cells, and increase of MDSCs and Tregs in the tumors. Similarly, the SLNs of these mice showed an increase of MDSCs, Tregs, and PD-L1 DCs, and decrease of T-cell stimulatory activity of DCs accompanied by decreased CD80 expression and TNF-α production. In addition, induction of tumor antigen-specific T cells from SLNs of the CT26-TGF-ß1-implanted mice was significantly reduced. These results demonstrate that overproduction of TGF-ß1 is critical for the generation of immunosuppressive microenvironments in both tumors and SLNs, which may result in suppression of spontaneous antitumor CD8 T-cell responses. Therefore, TGF-ß1 is an attractive target for restoration of immunosuppressive condition in cancer patients.
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Linfocitos T CD8-positivos/inmunología , Neoplasias Colorrectales/inmunología , Células Dendríticas/inmunología , Ganglios Linfáticos/inmunología , Linfocitos T Reguladores/inmunología , Factor de Crecimiento Transformador beta1/metabolismo , Animales , Antígeno B7-H1/metabolismo , Carcinogénesis/genética , Procesos de Crecimiento Celular/genética , Línea Celular Tumoral , Humanos , Tolerancia Inmunológica , Activación de Linfocitos/genética , Ratones , Ratones Endogámicos BALB C , Trasplante de Neoplasias , Factor de Crecimiento Transformador beta1/genética , Factor de Crecimiento Transformador beta1/inmunología , Transgenes/genética , Microambiente TumoralRESUMEN
Immunological status in tumor tissues varies among patients. Infiltration of memory-type CD8(+) T cells into tumors correlates with prognosis of patients with various cancers. However, the mechanism of the differential CD8(+) T cell infiltration has not been well investigated. In general, tumor-associated microenvironments, including tumor and sentinel lymph nodes, are under immunosuppressive conditions such that the immune system is not able to eliminate cancer cells without immune-activating interventions. Constitutive activation of various signaling pathways in human cancer cells triggers multiple immunosuppressive cascades that involve various cytokines, chemokines, and immunosuppressive cells. Signaling pathway inhibitors could inhibit these immunosuppressive cascades by acting on either cancer or immune cells, or both. In addition, common signaling mechanisms are often utilized for multiple hallmarks of cancer (e.g., cell proliferation/survival, invasion/metastasis, and immunosuppression). Therefore, targeting these common signaling pathways may be an attractive strategy for cancer therapy including immunotherapy.
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Inmunosupresores/uso terapéutico , Inmunoterapia/métodos , Terapia Molecular Dirigida/métodos , Neoplasias/inmunología , Animales , Linfocitos T CD8-positivos/citología , Humanos , Sistema de Señalización de MAP Quinasas , Ratones , FN-kappa B/metabolismo , Neoplasias/terapia , Proteínas Proto-Oncogénicas B-raf/metabolismo , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , beta Catenina/metabolismoRESUMEN
Lymph node metastasis is a poor prognostic factor for patients with head and neck squamous cell carcinoma (HNSCC). However, its molecular mechanism has not yet been fully understood. In our study, we investigated the expression of CCR4 and its ligand CCL22 in the HNSCC tumor microenvironment and found that the CCR4/CCL22 axis was involved in lymph node metastasis of HNSCC. CCR4 was expressed in 20 of 31 (64.5%) human tongue cancer tissues, and its expression was significantly correlated with lymph node metastasis (p < 0.01) and lymphatic invasion (p < 0.05). CCR4 was expressed in three of five human HNSCC cell lines tested. CCR4(+) HNSCC cells, but not CCR4(-) cells, showed enhanced migration toward CCL22, indicating that functional CCR4 was expressed in HNSCC cell lines. CCL22 was also expressed in cancer cells (48.4% of tongue cancer tissues) or CD206(+) M2-like macrophages infiltrated in tumors and draining lymph nodes. CCL22 produced by cancer cells or CD206(high) M2-like macrophages increased the cell motility of CCR4(+) HNSCC cells in vitro in an autocrine or paracrine manner. In the mouse SCCVII in vivo model, CCR4(+) cancer cells, but not CCR4(-) cells, metastasized to lymph nodes which contained CCL22 producing M2-like macrophages. These results demonstrate that lymph node metastasis of CCR4(+) HNSCC is promoted by CCL22 in an autocrine or M2-like macrophage-dependent paracrine manner. Therefore, the CCR4/CCL22 axis may be an attractive target for the development of diagnostic and therapeutic strategies for patients with HNSCC.
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Carcinoma de Células Escamosas/inmunología , Carcinoma de Células Escamosas/metabolismo , Comunicación Celular , Quimiocina CCL22/metabolismo , Neoplasias de Cabeza y Cuello/inmunología , Neoplasias de Cabeza y Cuello/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Receptores CCR4/metabolismo , Anciano , Anciano de 80 o más Años , Animales , Comunicación Autocrina , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Movimiento Celular/genética , Modelos Animales de Enfermedad , Femenino , Expresión Génica , Neoplasias de Cabeza y Cuello/patología , Humanos , Ganglios Linfáticos/metabolismo , Ganglios Linfáticos/patología , Metástasis Linfática , Masculino , Ratones , Persona de Mediana Edad , Comunicación Paracrina , Carcinoma de Células Escamosas de Cabeza y CuelloRESUMEN
Endomitosis and endoreplication are atypical modes of cell cycle that results in genome duplication in single nucleus. Because the cell size of given cell type is generally proportional to the nuclear DNA content, endoreplication and endomitosis are effective strategy of cell growth, which are widespread in multicellular organisms, especially those in plant kingdom. We found that these processes might be differently regulated by GIGAS CELL1 (GIG1) and its paralog UV-INSENSITIVE4 (UVI4) in Arabidopsis thaliana. GIG1 and UVI4 may negatively regulate activities of anaphase-promoting complex or cyclosome (APC/C) ubiquitin ligase that acts as an important mitotic regulator. The gig1 mutation induced ectopic occurrence of endomitosis during somatic cell division, while it has been reported that uvi4 mutation resulted in premature occurrence of endoreplication during organ development. Overexpression of GIG1 and UVI4 dramatically increased the amount of mitotic cyclin, CYCB1;1, a well-known substrate of APC/C. Ectopic endomitosis in gig1 was enhanced by mutation in CYCB2;2 and suppressed by downregulation of APC10 encoding a core subunit of APC/C. Overexpression of CDC20.1, an activator protein of APC/C, further promoted the ectopic endomitosis in gig1. These findings suggest that endomitosis and endoreplication are regulated by similar molecular mechanisms, in which two related proteins, GIG1 and UVI4, may inhibit APC/C in different ways.
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Arabidopsis/genética , Proteínas de Ciclo Celular/genética , Endorreduplicación , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Genoma de Planta , Mitosis/genética , Ciclosoma-Complejo Promotor de la Anafase , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Ciclo Celular/metabolismo , División Celular/genética , Ciclina B/metabolismo , Regulación hacia Abajo , Expresión Génica , Mutación , Complejos de Ubiquitina-Proteína Ligasa/metabolismoRESUMEN
Indole is produced by tryptophanase during growth of enteric bacteria and accumulates in the culture medium. The physiological role of indole production is poorly understood. We discovered that enterohaemorrhagic Escherichia coli (EHEC) O157:H7 with a tnaA deletion has decreased secretion of EspA and EspB via the type III secretion system and as a result there is reduced formation of attaching and effacing (A/E) lesions in HeLa cells. Addition of indole restored and enhanced secretion of EspA and EspB and formation of A/E lesions by the tnaA deletion mutant EHEC. Indole addition moderately increased the promoter activity of LEE4 genes, including espA and espB, in the locus of enterocyte effacement. Thus in EHEC indole can serve to signal EspA and EspB expression and secretion and stimulate the ability of EHEC to form A/E lesions on human cells.
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Proteínas de la Membrana Bacteriana Externa/metabolismo , Infecciones por Escherichia coli/microbiología , Escherichia coli O157/metabolismo , Proteínas de Escherichia coli/metabolismo , Regulación Bacteriana de la Expresión Génica , Indoles/metabolismo , Proteínas de la Membrana Bacteriana Externa/genética , Escherichia coli O157/genética , Escherichia coli O157/patogenicidad , Proteínas de Escherichia coli/genética , Células HeLa , Humanos , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Regiones Promotoras Genéticas , Transporte de Proteínas , Eliminación de Secuencia , Triptofanasa/genética , Triptofanasa/metabolismoRESUMEN
Catechins, which are polyphenol compounds found in abundance in green tea, have elicited high interest due to their beneficial effects on health. Catechins have also been demonstrated to induce chromosomal aberrations in vitro, although no clastogenicity was confirmed in studies in vivo. We investigated the mechanism of catechin-induced chromosomal aberrations in CHL/IU cells. Addition of catalase suppressed chromosomal aberrations, indicating involvement of hydrogen peroxide (H2O2). We confirmed that substantial amounts of H2O2 are generated when catechins are incubated under in vitro culture conditions, whereas, interestingly, extremely low amounts of H2O2 were detected when catechins were incubated at the same concentration in water. Generation of H2O2 increased steeply above pH 6, indicating that pH is a key factor in determining how much H2O2 is generated via catechins in vitro. Our assessment indicates that humans have practically non-existent exposure to H2O2 when catechins are ingested in a beverage. Polyphenols, including catechins, are known to act as antioxidants due to their reducing potential. However, under in vitro culture conditions, catechins are thought to act primarily as pro-oxidants by reducing ambient or dissolved oxygen to form H2O2. Based on the above observations, we conclude that in vitro culture conditions as currently employed are inappropriate to address genotoxicity concerns regarding polyphenols, including catechins.
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Catequina/toxicidad , Aberraciones Cromosómicas , Peróxido de Hidrógeno/farmacología , Té/química , Animales , Catalasa/farmacología , Línea Celular , Cricetinae , Cricetulus , Especies Reactivas de Oxígeno , Medición de RiesgoRESUMEN
The acrS regulatory gene is located upstream of the acrEF multidrug efflux system genes. However, the roles of AcrS in regulation of drug efflux pumps have not been clearly understood. Here we show that AcrS represses other multidrug efflux genes, acrAB, which encode a major efflux system in Escherichia coli.