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

ABSTRACT

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.


Subject(s)
Genital Neoplasms, Male , Liposarcoma , Soft Tissue Neoplasms , Adult , Genital Neoplasms, Male/surgery , Humans , In Situ Hybridization, Fluorescence , Liposarcoma/genetics , Liposarcoma/surgery , Male , Proto-Oncogene Proteins c-mdm2/genetics
2.
Eur Rev Med Pharmacol Sci ; 24(6): 3331-3343, 2020 03.
Article in English | MEDLINE | ID: mdl-32271451

ABSTRACT

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.


Subject(s)
Calcium-Calmodulin-Dependent Protein Kinase Type 2/genetics , Hepatocytes/cytology , Liver Transplantation , Liver/surgery , Animals , Apoptosis/physiology , Cell Line , Cytochromes c/metabolism , Disease Models, Animal , Liver/blood supply , Liver/cytology , Membrane Potential, Mitochondrial/physiology , Rats , Rats, Sprague-Dawley , Reperfusion Injury/physiopathology
3.
Oncogene ; 35(42): 5539-5551, 2016 10 20.
Article in English | MEDLINE | ID: mdl-27157614

ABSTRACT

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.


Subject(s)
Breast Neoplasms/genetics , Breast Neoplasms/pathology , CD24 Antigen/genetics , Cadherins/genetics , Cell Transformation, Neoplastic/genetics , Gene Expression Regulation, Neoplastic , Homeodomain Proteins/genetics , Animals , Antigens, CD , Cadherins/metabolism , Cell Adhesion , Cell Line, Tumor , Cell Self Renewal/genetics , Cluster Analysis , Disease Models, Animal , Disease Progression , Epithelial-Mesenchymal Transition/genetics , Female , Gene Expression Profiling , Heterografts , Homeodomain Proteins/metabolism , Humans , Mice , Neoplasm Grading , Promoter Regions, Genetic , Protein Binding , Stem Cells/metabolism
4.
Insect Mol Biol ; 23(5): 644-55, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25039995

ABSTRACT

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.


Subject(s)
Aedes/genetics , Insect Proteins/genetics , MAP Kinase Kinase 4/genetics , Aedes/enzymology , Aedes/growth & development , Amino Acid Sequence , Animals , Base Sequence , Cloning, Molecular , Female , Insect Proteins/chemistry , Insect Proteins/metabolism , Larva/enzymology , MAP Kinase Kinase 4/chemistry , MAP Kinase Kinase 4/metabolism , Molecular Sequence Data , Mutagenesis, Site-Directed , Ovum/enzymology , Phylogeny , Pupa/enzymology , Reverse Transcriptase Polymerase Chain Reaction , Sequence Alignment , Signal Transduction
5.
Int J Med Inform ; 82(5): 378-86, 2013 May.
Article in English | MEDLINE | ID: mdl-23245809

ABSTRACT

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.


Subject(s)
Attitude of Health Personnel , Emergency Service, Hospital/standards , Hospital Information Systems , Nurses/psychology , Perception , Physicians/psychology , Quality of Health Care , Communication , Emergency Service, Hospital/organization & administration , Humans
6.
Appl Clin Inform ; 3(1): 38-51, 2012.
Article in English | MEDLINE | ID: mdl-23616899

ABSTRACT

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.
Article in English | MEDLINE | ID: mdl-21353694

ABSTRACT

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.


Subject(s)
Aluminum Compounds/chemistry , Calcium Compounds/chemistry , Oxides/chemistry , Silicate Cement/chemistry , Silicates/chemistry , Aluminum Compounds/therapeutic use , Biocompatible Materials/chemistry , Calcium Compounds/therapeutic use , Chemical Phenomena , Dental Pulp Diseases/therapy , Drug Combinations , Humans , Oxides/therapeutic use , Root Canal Filling Materials/chemistry , Root Canal Filling Materials/therapeutic use , Silicates/therapeutic use
9.
Clin Radiol ; 65(3): 223-9, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20152279

ABSTRACT

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.


Subject(s)
Carcinoma, Acinar Cell , Magnetic Resonance Imaging , Pancreatic Neoplasms , Tomography, X-Ray Computed , Adult , Aged , Carcinoma, Acinar Cell/diagnostic imaging , Carcinoma, Acinar Cell/pathology , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Pancreas, Exocrine , Pancreatic Neoplasms/diagnostic imaging , Pancreatic Neoplasms/pathology , Retrospective Studies , Sex Distribution , alpha-Fetoproteins/metabolism
10.
Dis Esophagus ; 23(2): 122-7, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19473206

ABSTRACT

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.


Subject(s)
Carcinosarcoma/epidemiology , Esophageal Neoplasms/epidemiology , Age Factors , Aged , Alcohol Drinking/epidemiology , Areca , Carcinoma, Squamous Cell/epidemiology , Carcinosarcoma/secondary , Endoscopy, Digestive System , Endosonography , Follow-Up Studies , Head and Neck Neoplasms/epidemiology , Humans , Incidence , Lymphatic Metastasis , Male , Middle Aged , Neoplasm Staging , Neoplasms, Second Primary/epidemiology , Polyps/epidemiology , Retrospective Studies , Risk Factors , Smoking/epidemiology , Survival Rate , Taiwan/epidemiology , Ulcer/epidemiology
11.
Int J Clin Pract ; 62(8): 1199-205, 2008 Aug.
Article in English | MEDLINE | ID: mdl-17537192

ABSTRACT

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.


Subject(s)
Bile Duct Neoplasms/pathology , Bile Ducts, Intrahepatic/pathology , Carcinoma, Hepatocellular/pathology , Cholangiocarcinoma/pathology , Liver Neoplasms/pathology , Magnetic Resonance Imaging/standards , Neoplasms, Multiple Primary/pathology , Tomography, X-Ray Computed/standards , Adult , Aged , Aged, 80 and over , Bile Duct Neoplasms/mortality , Carcinoma, Hepatocellular/mortality , Cholangiocarcinoma/mortality , Female , Humans , Liver Neoplasms/mortality , Lymphatic Metastasis , Male , Middle Aged , Multivariate Analysis , Neoplasm Invasiveness , Neoplasm Staging , Neoplasms, Multiple Primary/mortality , Prognosis , Survival Analysis , Survival Rate
12.
Clin Microbiol Infect ; 13(8): 801-6, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17488329

ABSTRACT

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.


Subject(s)
Acinetobacter Infections/genetics , Acinetobacter baumannii/genetics , DNA, Intergenic/genetics , Polymerase Chain Reaction/methods , Acinetobacter baumannii/classification , Acinetobacter baumannii/isolation & purification , Humans , Phylogeny , Ribotyping/methods , Sensitivity and Specificity
13.
Conf Proc IEEE Eng Med Biol Soc ; 2005: 5738-41, 2005.
Article in English | MEDLINE | ID: mdl-17281561

ABSTRACT

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.
Article in English | MEDLINE | ID: mdl-15316656

ABSTRACT

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.


Subject(s)
Apoptosis/drug effects , CD18 Antigens/metabolism , Cycloheximide/pharmacology , Drug Resistance, Neoplasm/physiology , Protein Synthesis Inhibitors/pharmacology , Caspases/metabolism , Cell Adhesion/physiology , Dose-Response Relationship, Drug , Humans , Kinetics , Phosphatidylinositol 3-Kinases/metabolism , Protein Kinase C/metabolism , U937 Cells
16.
Insect Mol Biol ; 12(6): 595-603, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14986920

ABSTRACT

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.


Subject(s)
Aedes/enzymology , Aedes/genetics , Gene Expression , Mitogen-Activated Protein Kinase Kinases/genetics , Signal Transduction , Aedes/immunology , Amino Acid Sequence , Animals , Base Sequence , Blotting, Northern , Blotting, Western , Cluster Analysis , DNA Primers , DNA, Complementary/genetics , Lipopolysaccharides/metabolism , Mitogen-Activated Protein Kinase Kinases/metabolism , Molecular Sequence Data , Myelin Basic Protein/metabolism , Phosphorylation , Protein Structure, Tertiary , Reverse Transcriptase Polymerase Chain Reaction , Sequence Alignment , Sequence Analysis, DNA
17.
Am J Physiol Heart Circ Physiol ; 281(6): H2518-27, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11709419

ABSTRACT

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.


Subject(s)
Potassium Channels, Voltage-Gated , Potassium Channels/genetics , Potassium Channels/metabolism , Receptors, Adrenergic, alpha-1/genetics , Adrenergic alpha-Agonists/pharmacology , Alkaloids , Alternative Splicing/physiology , Benzophenanthridines , Carcinogens/pharmacology , Enzyme Inhibitors/pharmacology , Gene Expression/physiology , Humans , Membrane Potentials/drug effects , Membrane Potentials/physiology , Mutagenesis, Site-Directed/physiology , Myocardium/cytology , Phenanthridines/pharmacology , Phenylephrine/pharmacology , Phorbol Esters/pharmacology , Phosphorylation , Protein Kinase C/antagonists & inhibitors , Protein Kinase C/metabolism , Receptors, Adrenergic, alpha-1/metabolism , Shal Potassium Channels
18.
Mol Cell Biochem ; 203(1-2): 59-71, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10724333

ABSTRACT

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.


Subject(s)
Cyclins/genetics , Genes, Tumor Suppressor , Phosphoric Monoester Hydrolases/genetics , Transcriptional Activation/genetics , Tumor Suppressor Proteins , Amino Acid Sequence , Base Sequence , Cell Division/genetics , Cell Line , Cyclin-Dependent Kinase Inhibitor p21 , DNA Primers , Humans , Neoplasms/genetics , Neoplasms/pathology , PTEN Phosphohydrolase , Promoter Regions, Genetic
19.
Oncogene ; 17(3): 357-65, 1998 Jul 23.
Article in English | MEDLINE | ID: mdl-9690517

ABSTRACT

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.


Subject(s)
Antineoplastic Agents/pharmacology , Aziridines/pharmacology , Benzoquinones/pharmacology , Cyclins/biosynthesis , Tumor Suppressor Protein p53/metabolism , Animals , Base Sequence , Binding Sites , Breast Neoplasms , Cell Line , Cell Survival/drug effects , Cyclin-Dependent Kinase Inhibitor p21 , Enzyme Inhibitors/metabolism , Female , Gene Expression Regulation/drug effects , HL-60 Cells , Humans , Luciferases/biosynthesis , Mice , Osteosarcoma , Promoter Regions, Genetic/drug effects , Recombinant Fusion Proteins/biosynthesis , Transfection , Tumor Cells, Cultured
20.
J Biol Chem ; 272(46): 29091-8, 1997 Nov 14.
Article in English | MEDLINE | ID: mdl-9360984

ABSTRACT

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.


Subject(s)
Cyclins/metabolism , Extracellular Matrix/metabolism , Tumor Suppressor Protein p53/metabolism , Animals , Cell Line , Cyclin A/genetics , Cyclin-Dependent Kinase Inhibitor p21 , Cyclins/genetics , Mice , Mice, Knockout , Promoter Regions, Genetic , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction
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