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1.
Zhonghua Bing Li Xue Za Zhi ; 51(1): 17-22, 2022 Jan 08.
Artículo en Chino | MEDLINE | ID: mdl-34979748

RESUMEN

Objective: To investigate the clinicopathological features and differential diagnoses of paratesticular liposarcoma. Methods: The cases were collected from 2012-2020, from the archives of the Department of Pathology, Peking University Third Hospital, with diagnosis confirmed by histology, immunostaining and FISH tests. Results: Totally 19 patients were enrolled (including 11 in-hospital patients and 8 consultant cases). The patients aged 37-84 years (mean 57 years). The preoperative clinical diagnoses were spermatic cord/inguinal masses (nine patients), scrotal masses (seven patients), and inguinal hernia (three patients). Six lesions recurred after local resection, including one case extending from pelvic liposarcoma. Histologically, there were 10 cases of well-differentiated liposarcoma (WDLPS) and nine cases of dedifferentiated liposarcoma (DDLPS). WDLPSs mostly showed the combined features of lipoma-like, inflammatory and sclerosing subtypes (six patients); the other four WDLPSs had pure lipoma-like subtype features. DDLPSs were low-grade (three patients) or high-grade (six patients), with the morphology resembling myxofibrosarcoma, inflammatory myofibroblastoma, spindle cell sarcoma, pleomorphic undifferentiated sarcoma and pleomorphic liposarcoma. Intense inflammatory cells infiltration was commonly observed in five WDLPSs and two DDLPSs. Ossification was observed in three tumors. Immunohistochemically, the tumors were positive for MDM2 (8/10) and CDK4 (10/10), which were expressed in lipo-differentiating cells, spindle cells in WDLPS, and in dediffferentiated components. S-100 was only expressed by lipocytes (10/10). CD34 expression was positive and diffuse in the stromal cells of WDLPSs and focal or diffuse in dedifferentiated areas (10/10). FISH tests with an MDM2 gene probe were positive (12/12). Conclusions: Paratesticular liposarcoma may be overlooked by both clinicians and pathologists. WDLPS and DDLPS predominate, showing various histologic divergences. The presence of amplification of the 12q14-q15 region (containing the MDM2 and CDK4 genes) is helpful for making the correct diagnosis.


Asunto(s)
Neoplasias de los Genitales Masculinos , Liposarcoma , Neoplasias de los Tejidos Blandos , Adulto , Neoplasias de los Genitales Masculinos/cirugía , Humanos , Hibridación Fluorescente in Situ , Liposarcoma/genética , Liposarcoma/cirugía , Masculino , Proteínas Proto-Oncogénicas c-mdm2/genética
2.
Eur Rev Med Pharmacol Sci ; 24(6): 3331-3343, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32271451

RESUMEN

OBJECTIVE: The warm ischemia-reperfusion injury confines the prevalence of allografts. To improve the success rate of allotransplantation, we designed experiments to study the mechanism of calcium-calmodulin-dependent protein kinase type 2 (CaMK II) in ischemia-reperfusion (I/R) injury. MATERIALS AND METHODS: We established the I/R model in SD rats and performed the liver transplantation (LT). As a result, the expression of CaMK II in tissues was detected. CaMK II was interfered with and overexpressed by the transference of the lentivirus vector, and the hepatocyte apoptosis and viability were inspected. At the same time, the content of cytochrome c and apoptosis-inducing factor (AIF) were determined. The measurement of mitochondrial membrane potential and detection of intercellular calcium levels were performed. RESULTS: The expression of CaMK II significantly increased and is highly corresponded with the duration of warm ischemia. In BRL-3A cells and liver tissues, increased cellular apoptosis and less viability had been observed in the CaMK II overexpression group. Cytochrome c and AIF were also largely increased compared to the interfered group. Moreover, apparent mitochondrial membrane potential loss has also been detected in the CaMK II overexpression group. CONCLUSIONS: It suggested that CaMK II induces cell apoptosis. Our findings may give a novel indication that inhibition of CaMK II could be a new way for the therapy of warm ischemia-reperfusion injury after LT in future clinical practice.


Asunto(s)
Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/genética , Hepatocitos/citología , Trasplante de Hígado , Hígado/cirugía , Animales , Apoptosis/fisiología , Línea Celular , Citocromos c/metabolismo , Modelos Animales de Enfermedad , Hígado/irrigación sanguínea , Hígado/citología , Potencial de la Membrana Mitocondrial/fisiología , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/fisiopatología
3.
Oncogene ; 35(42): 5539-5551, 2016 10 20.
Artículo en Inglés | MEDLINE | ID: mdl-27157614

RESUMEN

Loss of HOXA5 expression occurs frequently in breast cancer and correlates with higher pathological grade and poorer disease outcome. However, how HOX proteins drive differentiation in mammalian cells is poorly understood. In this paper, we investigated cellular and molecular consequences of loss of HOXA5 in breast cancer, and the role played by retinoic acid in HOXA5 function. Analysis of global gene expression data from HOXA5-depleted MCF10A breast epithelial cells, followed by validation, pointed to a role for HOXA5 in maintaining several molecular traits typical of the epithelial lineage such as cell-cell adhesion, tight junctions and markers of differentiation. Depleting HOXA5 in immortalized MCF10A or transformed MCF10A-Kras cells reduced their CD24+/CD44lo population, enhanced self-renewal capacity and reduced expression of E-cadherin (CDH1) and CD24. In the case of MCF10A-Kras, HOXA5 loss increased branching and protrusive morphology in Matrigel, all features suggestive of epithelial to basal transition. Further, orthotopically implanted xenografts of MCF10A-Kras-scr grew as well-differentiated pseudo-luminal carcinomas, while MCF10A-Kras-shHOXA5 cells formed aggressive, poorly differentiated carcinomas. Conversely, ectopic expression of HOXA5 in aggressive SUM149 or SUM159 breast cancer cells reversed the cellular and molecular alterations observed in the HOXA5-depleted cells. Retinoic acid is a known upstream regulator of HOXA5 expression. HOXA5 depletion in MCF10A cells engineered to express doxycycline-induced shHOXA5 slowed transition of cells from a less differentiated CD24-/CD44+ to the more differentiated CD24+/CD44+ state. This transition was promoted by retinal treatment, which upregulated endogenous HOXA5 expression and caused re-expression of occludin and claudin-7 (CLDN7). Expression of CDH1 and CD24 was transcriptionally upregulated by direct binding of HOXA5 to their promoter sequences as demonstrated by luciferase and ChIP analyses. Thus, loss of HOXA5 in mammary cells leads to loss of epithelial traits, an increase in stemness and cell plasticity, and the acquisition of more aggressive phenotypes.


Asunto(s)
Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Antígeno CD24/genética , Cadherinas/genética , Transformación Celular Neoplásica/genética , Regulación Neoplásica de la Expresión Génica , Proteínas de Homeodominio/genética , Animales , Antígenos CD , Cadherinas/metabolismo , Adhesión Celular , Línea Celular Tumoral , Autorrenovación de las Células/genética , Análisis por Conglomerados , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Transición Epitelial-Mesenquimal/genética , Femenino , Perfilación de la Expresión Génica , Xenoinjertos , Proteínas de Homeodominio/metabolismo , Humanos , Ratones , Clasificación del Tumor , Regiones Promotoras Genéticas , Unión Proteica , Células Madre/metabolismo
4.
Insect Mol Biol ; 23(5): 644-55, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25039995

RESUMEN

Protein kinases are known to be involved in a number of signal transduction cascades. Both the stress-activated Jun N-terminal kinase (JNK) and mitogen-activated protein kinase (MAPK) p38 pathways have been shown to correlate with the insect immune response to microbial infection. MAP kinase kinase 4 (MEK4) is an upstream kinase of JNK and p38 kinase. The cDNA of AaMEK4 was cloned and characterized. AaMEK4 was activated by microbial lysates of Gram-positive, Gram-negative bacteria and yeast. The conserved lysine (K112 ) and the putative phosphorylation sites (S238 and T242 ) were shown to be important for kinase activity by site-directed mutagenesis. A common MAPK docking site (MAPK_dsA) was found and in addition, a new nearby docking site, MAPK_dsB, was identified in the N-terminal noncatalytic domain of AaMEK4. MAPK_dsB was shown to be a unique element in the MEK4 family. In this study, both MAPK_dsA and _dsB were demonstrated to be important to AaMEK4 enzymatic activity for the downstream protein kinase, Aap38.


Asunto(s)
Aedes/genética , Proteínas de Insectos/genética , MAP Quinasa Quinasa 4/genética , Aedes/enzimología , Aedes/crecimiento & desarrollo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , Femenino , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Larva/enzimología , MAP Quinasa Quinasa 4/química , MAP Quinasa Quinasa 4/metabolismo , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Óvulo/enzimología , Filogenia , Pupa/enzimología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Transducción de Señal
5.
Int J Med Inform ; 82(5): 378-86, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23245809

RESUMEN

INTRODUCTION: Through our research into the design and evaluation of technology systems to improve the quality and safety of clinical communication, we have discovered that physicians and nurses differ in perspective regarding clinical prioritization and desirable response times. This has a number of important consequences including unnecessary interruptions, escalating conflict and deterioration in interprofessional relationships. Understanding the differing perspectives on clinical prioritization, or the gap in perceived urgency, may improve interprofessional relationships. METHODS: We conducted a mixed-methods study utilizing both qualitative (semi-structured interviews) and quantitative (surveys) methods to determine the gap between perceived urgency among physicians and nurses. The survey comprised of real messages extracted from the clinical communication system that was implemented. Physicians and nurses reviewed the messages and assigned an urgency level to each. The semi-structured interviews used open-ended questions to act as a guide to highlight key themes of interest. Thematic analysis, frequency tabulation, and triangulation were used to analyze the data. RESULTS: Although the surveys demonstrated concordance between physicians and nurses when independently ranking the urgency of clinical messages (kappa=0.66 SE 0.15), agreement was only fair in comparison to the urgency identified by the original nurse who sent the message (kappa=0.22 SE 0.18). We hypothesize that clinical context has a major role in defining urgency and may explain this finding. The survey data was triangulated with the semi-structured interview data and it was determined that the desired response time significantly impacted the sender's message prioritization. For example, shift changes and anxious family members were associated with discordant prioritizations. DISCUSSION: This study demonstrated that the perceived communication urgency gap between sending nurses and receiving physicians was primarily related to timeframe and context, not clinical condition. Most disagreement occurred when nurses used urgent messaging for time sensitive but not clinically urgent issues in an effort to expedite the resolution of their issue by the physicians. These results indicate the need for clinical communication systems to incorporate decision support around both clinical prioritization and expected response time in their design. Effective interprofessional communication is essential to the provision of safe, quality-based healthcare; these results highlight some of the sociotechnical aspects of health information technology implementation that must be considered.


Asunto(s)
Actitud del Personal de Salud , Servicio de Urgencia en Hospital/normas , Sistemas de Información en Hospital , Enfermeras y Enfermeros/psicología , Percepción , Médicos/psicología , Calidad de la Atención de Salud , Comunicación , Servicio de Urgencia en Hospital/organización & administración , Humanos
6.
Appl Clin Inform ; 3(1): 38-51, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23616899

RESUMEN

BACKGROUND: Clinical communication is recognized as a major source of errors in hospitals. The lack of documentation of communication, especially among verbal interactions, often creates hindrances and impedes improvement efforts. By providing smartphones to residents and encouraging nurses to communicate with residents by email shifted much of the communication to emails which permitted analysis of content. OBJECTIVE: Description on the interprofessional email communication between doctors and nurses occurring on the general internal medicine wards at two academic hospitals. DESIGN: A prospective analysis of email communications between doctors and nurses. SETTING: 34 out of the 67 residents who were on the general medicine clinical teaching units consented to allow analysis of their emails over a 6 month period. MAIN MEASURES: Statistical tabulations were performed on the volume and frequency of communications as well the response time of messages. Two physicians coded the content of randomly selected emails for urgency, emotion, language, type of interaction, and subject content. KEY RESULTS: A total of 13,717 emails were available for analysis. Among the emails from nurses, 39.1% were requests for a call back, 18.9% were requests for a response by email and the remaining 42.0% indicated no response was required from physicians. For the messages requesting a response by email, only 50% received an email response. Email responses had a median response time of 2.3 minutes. Content analysis revealed that messages were predominantly non-urgent. The two most frequent purposes for communications were to convey information (91%) and to request action by the physician (36%). CONCLUSIONS: A smartphone-based email system facilitated the description and content analysis of a large amount of email communication between physicians and nurses. Our findings provide a picture of the communication between physicians, nurses and other healthcare professionals. This work may help inform the further development of information and communications technology that can improve clinical communication.

7.
Dent Mater ; 27(5): 407-22, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21353694

RESUMEN

OBJECTIVES: To review the current status and understanding of Portland cement-like endodontic materials commonly referred to by the trade designation "MTA" (alias "Mineral Trioxide Aggregate"), and to present an outline setting reaction scheme, hitherto unattempted. METHOD: The literature was searched using on-line tools, overlapping an earlier substantial review to pick up any omissions, including that in respect of ordinary Portland cement (OPC), with which MTA shares much. The search was conducted for the period January 2005 to December 2009 using 'MTA', 'GMTA', 'WMTA', and 'mineral AND trioxide AND aggregate' as keywords, with various on-line search engines including ScienceDirect (http://www.sciencedirect.com), SAGE Journals Online (http://online.sagepub.com), Wiley Online Library (http://onlinelibrary.wiley.com), SciELO Scientific electronic library online (http://www.scielo.br/scielo.php), JSTOR (http://www.jstor.org), and Scopus (http://www.scopus.com). References of articles found were cross-checked where appropriate for missed publications. Manufacturers' and related websites were searched with Google Search (http://www.google.com.hk). RESULTS: A generic name for this class of materials, Hydraulic Silicate Cement (HSC), is proposed, and an outline reaction scheme has been deduced. HSC has distinct advantages apparent, including sealing, sterilizing, mineralizing, dentinogenic and osteogenic capacities, which research continues to demonstrate. However, ad hoc modifications have little supporting justification. SIGNIFICANCE: While HSC has a definite place in dentistry, with few of the drawbacks associated with other materials, some improvements in handling and other properties are highly desirable, as are studies of the mechanisms of the several beneficial physiological effects. Reference to the extensive, but complex, literature on OPC may provide the necessary insight.


Asunto(s)
Compuestos de Aluminio/química , Compuestos de Calcio/química , Óxidos/química , Cemento de Silicato/química , Silicatos/química , Compuestos de Aluminio/uso terapéutico , Materiales Biocompatibles/química , Compuestos de Calcio/uso terapéutico , Fenómenos Químicos , Enfermedades de la Pulpa Dental/terapia , Combinación de Medicamentos , Humanos , Óxidos/uso terapéutico , Materiales de Obturación del Conducto Radicular/química , Materiales de Obturación del Conducto Radicular/uso terapéutico , Silicatos/uso terapéutico
9.
Clin Radiol ; 65(3): 223-9, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20152279

RESUMEN

AIM: To document the computed tomography (CT) and magnetic resonance imaging (MRI) features of acinar cell carcinoma of the pancreas and to correlate them with pathological findings to determine the unique imaging manifestations of this rare subtype tumour of the pancreas. MATERIALS AND METHODS: From January 1986 to August 2008, six patients (five men and one woman, mean age 61.3 years) with histologically proven acinar cell carcinoma of the pancreas underwent CT (n=6) and MRI (n=4) examinations. The imaging features of each tumour were documented and compared with pathological findings. RESULTS: The tumours were distributed in the head (n=4), body (n=1), and tail (n=1) of the pancreas. Four masses (67%) were uniformly or partially well-defined with thin, enhancing capsules. Central cystic components were found in five tumours (83%). Two tumours (33%) exhibited intratumoural haemorrhage, and one tumour (17%) had amorphous intratumoural calcification. In both CT and MRI, the tumours enhanced less than the adjacent normal pancreatic parenchyma. The signal intensity on MRI was predominantly T1 hypointense and T2 iso- to hyperintense. CONCLUSION: Acinar cell carcinoma of the pancreas has distinct imaging features, and both CT and MRI are useful and complementary imaging methods.


Asunto(s)
Carcinoma de Células Acinares , Imagen por Resonancia Magnética , Neoplasias Pancreáticas , Tomografía Computarizada por Rayos X , Adulto , Anciano , Carcinoma de Células Acinares/diagnóstico por imagen , Carcinoma de Células Acinares/patología , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Páncreas Exocrino , Neoplasias Pancreáticas/diagnóstico por imagen , Neoplasias Pancreáticas/patología , Estudios Retrospectivos , Distribución por Sexo , alfa-Fetoproteínas/metabolismo
10.
Dis Esophagus ; 23(2): 122-7, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19473206

RESUMEN

Carcinosarcoma of the esophagus is a rare neoplasm with both carcinomatous and sarcomatous components. This study aimed to investigate its clinicopathologic features and endoscopic characteristics. The data of patients diagnosed to have esophageal carcinosarcoma pathologically in the past 30 years (January 1976-December 2007) were reviewed. Of 3318 cases of esophageal malignancy, 12 were diagnosed as esophageal carcinosarcoma, with an incidence of 0.36%. All of the cases were male with a mean age of 62.3 years. Of the 12 tumors, 8 were polypoid type, and 4 were ulcerative type. In the endoscopic ultrasonography examination, the tumors show heterogeneous hypoechoic lesions with irregular outer margins and internal multicystic components. Four patients (33.3%) had previous head and neck squamous cell carcinoma that occurred metachronously. This is the first report about the characteristics of esophageal carcinosarcoma under endoscopic ultrasonography examination. The relationship between esophageal carcinosarcomas and head and neck cancer needs further investigation.


Asunto(s)
Carcinosarcoma/epidemiología , Neoplasias Esofágicas/epidemiología , Factores de Edad , Anciano , Consumo de Bebidas Alcohólicas/epidemiología , Areca , Carcinoma de Células Escamosas/epidemiología , Carcinosarcoma/secundario , Endoscopía del Sistema Digestivo , Endosonografía , Estudios de Seguimiento , Neoplasias de Cabeza y Cuello/epidemiología , Humanos , Incidencia , Metástasis Linfática , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Neoplasias Primarias Secundarias/epidemiología , Pólipos/epidemiología , Estudios Retrospectivos , Factores de Riesgo , Fumar/epidemiología , Tasa de Supervivencia , Taiwán/epidemiología , Úlcera/epidemiología
11.
Int J Clin Pract ; 62(8): 1199-205, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17537192

RESUMEN

This study was designed to assess the clinical usefulness of imaging for predicting the prognosis of patients with combined hepatocellular cholangiocarcinoma (cHCC-CC). Between 1999 and 2004, 30 patients with histopathologically proven cHCC-CC underwent computed tomography (CT) or magnetic resonance imaging (MRI). The imaging data and survival were analysed. Univariate log-rank analysis of imaging findings revealed that tumour necrosis, bile duct invasion, major vascular branch invasion, multiplicity, bilobar distribution, regional lymph node involvement, regional organ invasion, distant metastasis and ascites had adverse influences on overall survival. Multivariate Cox proportional hazard analysis demonstrated that major vascular branch invasion, regional organ invasion, nodal and distant metastases were independent prognostic factors that adversely affected overall survival rates. Overall cumulative survival rates at 1, 3 and 5 years were 53%, 26% and 12%, respectively. Analysing the survival of our patients by using clinical stages of the newly updated American Joint Committee on Cancer (AJCC) classification for liver neoplasm based on the imaging findings, we found significant differences between stages I/II and III (p < 0.001) and between stages III and IV (p = 0.040). We conclude CT or MRI can be used to identify the prognostic factors and to estimate the outcomes of patients with cHCC-CC.


Asunto(s)
Neoplasias de los Conductos Biliares/patología , Conductos Biliares Intrahepáticos/patología , Carcinoma Hepatocelular/patología , Colangiocarcinoma/patología , Neoplasias Hepáticas/patología , Imagen por Resonancia Magnética/normas , Neoplasias Primarias Múltiples/patología , Tomografía Computarizada por Rayos X/normas , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de los Conductos Biliares/mortalidad , Carcinoma Hepatocelular/mortalidad , Colangiocarcinoma/mortalidad , Femenino , Humanos , Neoplasias Hepáticas/mortalidad , Metástasis Linfática , Masculino , Persona de Mediana Edad , Análisis Multivariante , Invasividad Neoplásica , Estadificación de Neoplasias , Neoplasias Primarias Múltiples/mortalidad , Pronóstico , Análisis de Supervivencia , Tasa de Supervivencia
12.
Clin Microbiol Infect ; 13(8): 801-6, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17488329

RESUMEN

Acinetobacter baumannii has emerged as a serious cause of nosocomial infections. Rapid identification of this pathogen is required so that appropriate therapy can be given and outbreaks controlled. This study evaluated a multiplex PCR and an automated ribotyping system for the rapid identification of Acinetobacter baumannii. In total, 22 different reference strains and 138 clinical isolates of Acinetobacter spp., identified by 16S-23S rRNA intergenic spacer (ITS) sequence analysis, were evaluated. All A. baumannii isolates (82 clinical isolates and one reference strain) were identified by the multiplex PCR method (specificity 100%). The sensitivity and specificity of the ribotyping system for identification of A. baumannii were 85.5% (71/83) and 93.5% (72/77), respectively. An additional 100 clinical isolates belonging to the Acinetobacter calcoaceticus-A. baumannii complex were used to compare these two methods for identification of A. baumannii, and this comparison revealed a level of disagreement of 14% (14 isolates). The accuracy of the multiplex PCR was 100%, which was confirmed by sequence analysis of the ITS and recA gene of these isolates. Thus, the multiplex PCR method dramatically increased the efficiency and speed of A. baumannii identification.


Asunto(s)
Infecciones por Acinetobacter/genética , Acinetobacter baumannii/genética , ADN Intergénico/genética , Reacción en Cadena de la Polimerasa/métodos , Acinetobacter baumannii/clasificación , Acinetobacter baumannii/aislamiento & purificación , Humanos , Filogenia , Ribotipificación/métodos , Sensibilidad y Especificidad
13.
Conf Proc IEEE Eng Med Biol Soc ; 2005: 5738-41, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-17281561

RESUMEN

Preventing accidents caused by drowsiness behind the steering wheel is highly desirable but requires techniques for continuously estimating driver's abilities of perception, recognition and vehicle control abilities. This paper proposes methods for drowsiness estimation that combine the electroencephalogram (EEG) log subband power spectrum, correlation analysis, principal component analysis, and linear regression models to indirectly estimate driver's drowsiness level in a virtual-reality-based driving simulator. Results show that it is feasible to quantitatively monitor driver's alertness with concurrent changes in driving performance in a realistic driving simulator.

14.
Cell Mol Life Sci ; 61(16): 2071-82, 2004 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15316656

RESUMEN

In this study with cycloheximide (CHX, an inhibitor of protein synthesis) and the human leukaemic cell line U937, a novel form of chemoresistance, which we termed sudden drug resistance (SDR), was identified using Hoechst33258 staining, Western blot and DNA Ladder. CHXhigh (10-100 microg/ml)-induced apoptosis can spontaneously subside after 4-6 h or can be inhibited by short-term preincubation with CHXlow (2.5 microg/ml). Unlike typical multidrug resistance, SDR is not caused by reduced drug accumulation or altered protein expression, and may be associated with a non-P-glycoprotein mechanism. To uncover this underlying mechanism, we focused on U937 cell aggregation promoted by CHX, because cell adhesion has been suggested to influence cell survival and prevent apoptosis. EDTA, or anti-CD18 monoclonal antibody, but not EGTA, acetylsalicylic acid or RGDS tetrapeptide, abrogated this homotypic aggregation and greatly increased CHX-induced apoptosis in a time-dependent manner, while fibrinogen and soluble intercellular adhesion molecule-1 exerted opposite effects. These results establish that beta2-integrin engagement is a key mediator of SDR, although it may be non-exclusive. This finding supplements the classical basis of chemoresistance and may provide another opportunity for improved leukemia therapy.


Asunto(s)
Apoptosis/efectos de los fármacos , Antígenos CD18/metabolismo , Cicloheximida/farmacología , Resistencia a Antineoplásicos/fisiología , Inhibidores de la Síntesis de la Proteína/farmacología , Caspasas/metabolismo , Adhesión Celular/fisiología , Relación Dosis-Respuesta a Droga , Humanos , Cinética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteína Quinasa C/metabolismo , Células U937
16.
Insect Mol Biol ; 12(6): 595-603, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14986920

RESUMEN

In mammals, the mitogen-activated protein (MAP) kinase pathway is one of the four major signalling systems that respond to stress and inflammatory stimuli. A full-length cDNA corresponding to Aedes aegypti MAP kinase kinase 3 (AaMEK3) was cloned and sequenced. It is 1.7 kb and contains an open reading frame of 334 amino acids and eleven conserved kinase domains, including signatures of a putative serine/threonine kinase active site and an ATP binding site. The messenger (mRNA) and protein expression levels of AaMEK3 are enhanced post bacterial inoculation. The in vitro kinase activity assay reveals that (1) AaMEK3 is not autophosphorylated but can phosphorylate myelin basic protein successfully, and (2) it is slightly enhanced by lipopolysaccharide stimulation. This suggests that AaMEK3 may be involved in mosquito immune signalling.


Asunto(s)
Aedes/enzimología , Aedes/genética , Expresión Génica , Quinasas de Proteína Quinasa Activadas por Mitógenos/genética , Transducción de Señal , Aedes/inmunología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Northern Blotting , Western Blotting , Análisis por Conglomerados , Cartilla de ADN , ADN Complementario/genética , Lipopolisacáridos/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Datos de Secuencia Molecular , Proteína Básica de Mielina/metabolismo , Fosforilación , Estructura Terciaria de Proteína , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Análisis de Secuencia de ADN
17.
Am J Physiol Heart Circ Physiol ; 281(6): H2518-27, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11709419

RESUMEN

The transient outward potassium current (I(to)) is an important repolarizing current in the mammalian heart. I(to) is regulated by adrenergic stimulation; however, the effect of agonists on this current, and consequently the action potential duration and profile, is variable. An important source of the variability is the difference in the channel genes that underlie I(to). There are two subfamilies of candidate genes that are likely to encode I(to) in the mammalian heart: Kv4 and Kv1.4; the predominance of either gene is a function of the species, stage of development, and region of the heart. The existence of different isoforms of the Kv4 family (principally Kv4.2 or Kv4.3) further complicates the effect of alpha-adrenergic modulation of cardiac I(to). In the human ventricle, hKv4.3 is the predominant gene underlying I(to). Two splice variants of human Kv4.3 (hKv4.3) are present in the human ventricle; the longer splice variant contains a 19-amino acid insert in the COOH-terminus with a consensus protein kinase C (PKC) site. We used heterologous expression of hKv4.3 splice variants and studies of human ventricular myocytes to demonstrate that alpha-adrenergic modulation of I(to) occurs through a PKC signaling pathway and that only the long splice variant (hKv4.3-L) is modulated via this pathway. Only a single hKv4.3-L monomer in the tetrameric I(to) channel is required to confer sensitivity to phenylephrine (PE). Mutation of the PKC site in hKv4.3-L eliminates alpha-adrenergic modulation of the hKv4.3-encoded current. The similar, albeit less robust, modulation of human ventricular I(to) by PE suggests that hKv4.3-L is expressed in a functional form in the human heart.


Asunto(s)
Canales de Potasio con Entrada de Voltaje , Canales de Potasio/genética , Canales de Potasio/metabolismo , Receptores Adrenérgicos alfa 1/genética , Agonistas alfa-Adrenérgicos/farmacología , Alcaloides , Empalme Alternativo/fisiología , Benzofenantridinas , Carcinógenos/farmacología , Inhibidores Enzimáticos/farmacología , Expresión Génica/fisiología , Humanos , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Mutagénesis Sitio-Dirigida/fisiología , Miocardio/citología , Fenantridinas/farmacología , Fenilefrina/farmacología , Ésteres del Forbol/farmacología , Fosforilación , Proteína Quinasa C/antagonistas & inhibidores , Proteína Quinasa C/metabolismo , Receptores Adrenérgicos alfa 1/metabolismo , Canales de Potasio Shal
18.
Mol Cell Biochem ; 203(1-2): 59-71, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10724333

RESUMEN

The recently discovered tumor suppressor gene PTEN has been found mutated in many types of advanced tumors. When introduced into tumor cells that lack the wild-type allele of the gene, PTEN was able to suppress the growth of these cells. Here, we have analyzed how PTEN might alter cell cycle-regulatory controls to achieve this growth-inhibitory effect. We found that overexpression of PTEN stimulates the synthesis of three inhibitors of cyclin-dependent kinases, p21WAF1, p27KIP1, and p57KIP2. This effect is very specific, as the expression of other components of the cell cycle engine, various cyclins and cyclin-dependent kinases, is not affected. For p21WAF1 we show that this induction is due to the p53-independent transcriptional activation of its promoter. In addition, increased expression of PTEN rendered the cells more sensitive to apoptotic cell death. Therefore, our data suggest a two-fold mechanism of growth inhibition by PTEN: one that acts via the increased expression of CKIs such as p21WAF1, and another that augments the cellular propensity for apoptotic cell death.


Asunto(s)
Ciclinas/genética , Genes Supresores de Tumor , Monoéster Fosfórico Hidrolasas/genética , Activación Transcripcional/genética , Proteínas Supresoras de Tumor , Secuencia de Aminoácidos , Secuencia de Bases , División Celular/genética , Línea Celular , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Cartilla de ADN , Humanos , Neoplasias/genética , Neoplasias/patología , Fosfohidrolasa PTEN , Regiones Promotoras Genéticas
19.
Oncogene ; 17(3): 357-65, 1998 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-9690517

RESUMEN

Quinones are the second largest family of anticancer drugs clinically used in the United States. However, their exact mode of action at the cellular and molecular level is not completely understood. We have shown earlier that the quinone 3,6-diaziridinyl-1,4-benzoquinone (DZQ) leads to the increased expression of p21waf1/cip1/sdi1 protein, an inhibitor of cyclin-dependent kinases. Because p21 has been established as an important negative regulator of the cell cycle, we further investigated the molecular basis of p21 induction by DZQ. Here we report that the induction of p21 by DZQ is regulated at the transcriptional level, and requires the activation of p53, a tumor suppressor protein. In cells that lack functional p53 protein, DZQ-mediated p21 induction is greatly diminished. However, the introduction of a wild type p53 gene into p53-negative cells restores the strong DZQ-inducibility of p21. Restoration of wild type p53 status in HL60 myeloid leukemia cells significantly increases the cells' sensitivity to the cytotoxic effects of DZQ. Thus, our results indicate that the p53-p21 pathway may play a central role in mediating the gene-regulatory and cytotoxic effects of aziridinylbenzoquinones.


Asunto(s)
Antineoplásicos/farmacología , Aziridinas/farmacología , Benzoquinonas/farmacología , Ciclinas/biosíntesis , Proteína p53 Supresora de Tumor/metabolismo , Animales , Secuencia de Bases , Sitios de Unión , Neoplasias de la Mama , Línea Celular , Supervivencia Celular/efectos de los fármacos , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Inhibidores Enzimáticos/metabolismo , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Células HL-60 , Humanos , Luciferasas/biosíntesis , Ratones , Osteosarcoma , Regiones Promotoras Genéticas/efectos de los fármacos , Proteínas Recombinantes de Fusión/biosíntesis , Transfección , Células Tumorales Cultivadas
20.
J Biol Chem ; 272(46): 29091-8, 1997 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-9360984

RESUMEN

The proliferation of most cells is strictly dependent on cell-matrix interactions, a phenomenon called anchorage dependence. Because tumor cells often are independent of this regulation, it is important to characterize the molecular pathways that control cellular proliferation after detachment of cells from their matrix. In this report, we investigated a possible role of p53 and one of its target genes, p21(waf1/cip1), as components of anchorage-dependent cell growth control. We found that p53 protein is rapidly activated upon the disruption of cellular attachment. This led to p21 transcriptional activation via two p53-binding sites in its promoter. Elevated p21 protein levels blocked transcription and activity of the cell cycle-regulator cyclin A, and cells became arrested in G1 of the cell cycle. Under the same conditions, fibroblasts from p53 knock-out mice did not activate p21 and did not down-regulate cyclin A expression but rather induced another cell cycle inhibitor, p27. Thus, our results characterize a chain of events, starting from the activation of p53 and proceeding via p21 to cyclin A, that is activated in response to the loss of cellular adherence. This p53-regulated pathway may constitute one of a few redundant systems to ensure proper cell control in multicellular organisms.


Asunto(s)
Ciclinas/metabolismo , Matriz Extracelular/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Animales , Línea Celular , Ciclina A/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/genética , Ratones , Ratones Noqueados , Regiones Promotoras Genéticas , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transducción de Señal
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