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1.
RSC Adv ; 12(41): 26575-26579, 2022 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-36275165

RESUMEN

The enigmatic self-assembling ability of nanodiamond (ND) particles has been discovered herein. Diamond-rich crystalline nanosheets with thickness of approximately ∼25 nm were grown from a Langmuir monolayer of arachidic acid (AA) at the interface between air and a dilute aqueous ND solution. Their fine rectangular shapes with uniform uniaxial birefringence indicate appreciable crystallinity, thus supporting that they are hydrated colloidal crystals of homogeneous ND particles.

2.
ACS Omega ; 7(51): 47812-47820, 2022 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-36591147

RESUMEN

We demonstrate the formation of a well-organized thin film of two-dimensional (2D) layered (C18H37NH3)2PbI4 hybrid perovskite by immersing octadecyl amine (ODA) Langmuir-Blodgett (LB) films in an aqueous solution of PbI2/HI. The immersed films exhibit a sharp absorption band at 486 nm (2.55 eV), which is assigned to the excitonic absorption. The film exhibits a bright green emission under ultraviolet light at room temperature. The photoluminescence spectrum has a distinct peak at 497 nm (2.49 eV) and is a mirror image of the absorption spectrum. X-ray diffraction (XRD) analyses reveal that the film has a bilayer-like structure with a d-spacing of 6.4 nm, which is equal to that of a (C18H37NH3)2PbI4 perovskite single crystal with a quantum well (QW) structure. Only intense peaks of the (0 0 l) (l = 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24) reflections are observed in the out-of-plane XRD pattern, indicating that the c axis is vertically oriented with respect to the substrate surface, and the orientational order is remarkably high. Fourier transform infrared spectroscopy reveals that the ODA molecules are protonated in the PbI2/HI solution. These results suggest that the nitrogen atoms of the ODA molecules in the film are protonated in the PbI2/HI solution, and then, inorganic layers of the PbI6 octahedra are intercalated in the alkyl ammonium film to neutralize the positive charge and form a QW structure. Fluorescence microscopy observation reveals that the 2D layered (C18H37NH3)2PbI4 film has a relatively uniform surface, reflecting the well-organized layered structure of the base material (ODA LB film). Because the intercalation process can be applied to various metal cations and halogen anions, we believe that the proposed technique will aid in the development of highly efficient 2D layered organic-inorganic hybrid perovskite materials.

3.
Langmuir ; 36(2): 554-562, 2020 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-31867973

RESUMEN

Spherulitic crystallization in Langmuir-Blodgett (LB) films of the ditetradecyldimethylammonium-Au(dmit)2 [2C14N+Me2-Au(dmit)2] salt has been characterized by polarized light microscopy, Fourier-transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) analyses. Analyses by differential scanning calorimetry (DSC) for the bulk crystals indicate that annealing in the temperature range of 58-100 °C may be appropriate to improve the order in the LB film. The polarized light microscopy measurement further revealed that a spherulite structure was formed after the film was annealed at 80 °C for 60 min. FT-IR spectroscopy measurements demonstrated that the order of the principal hydrocarbon chains was improved and that the rotation of CH3 groups was hindered by the annealing. Out-of-plane XRD analyses revealed that the d-spacing of the 2C14N+Me2-Au(dmit)2 LB film changed from 3.1 to 2.5 nm upon annealing. We hypothesize that a layered structure with interdigitated hydrocarbon chains, which is equivalent to or close to that of the corresponding bulk crystal, has been realized in the LB film by annealing. We consider that two different kinds of one-dimensional (1D) interactions along the a-axis are the driving forces to realize the spherulite structure in the LB system; one is an extended 1D contact due to the pronounced interdigitation of the alkyl chains of the ammonium ion, which plays a role similar to that of the folding of chains in the lamellar structures of polymers, and the other is a 1D extended sulfur-sulfur contact between Au(dmit)2 dimer pairs. So far, spherulite formation in LB films has been reported almost exclusively for polymerized materials. Here, we demonstrate that a spherulite texture can also be formed in LB films based on nonpolymerized materials via the interdigitation of hydrocarbon chains, leading to a new well-ordered state.

4.
J Pathol Inform ; 4: 24, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24244882

RESUMEN

BACKGROUND: Recent advances in information technology have allowed the development of a telepathology system involving high-speed transfer of high-volume histological figures via fiber optic landlines. However, at present there are geographical limits to landlines. The Japan Aerospace Exploration Agency (JAXA) has developed the "Kizuna" ultra-high speed internet satellite and has pursued its various applications. In this study we experimented with telepathology in collaboration with JAXA using Kizuna. To measure the functionality of the Wideband InterNet working engineering test and Demonstration Satellite (WINDS) ultra-high speed internet satellite in remote pathological diagnosis and consultation, we examined the adequate data transfer speed and stability to conduct telepathology (both diagnosis and conferencing) with functionality, and ease similar or equal to telepathology using fiber-optic landlines. MATERIALS AND METHODS: We performed experiments for 2 years. In year 1, we tested the usability of the WINDS for telepathology with real-time video and virtual slide systems. These are state-of-the-art technologies requiring massive volumes of data transfer. In year 2, we tested the usability of the WINDS for three-way teleconferencing with virtual slides. Facilities in Iwate (northern Japan), Tokyo, and Okinawa were connected via the WINDS and voice conferenced while remotely examining and manipulating virtual slides. RESULTS: Network function parameters measured using ping and Iperf were within acceptable limits. However; stage movement, zoom, and conversation suffered a lag of approximately 0.8 s when using real-time video, and a delay of 60-90 s was experienced when accessing the first virtual slide in a session. No significant lag or inconvenience was experienced during diagnosis and conferencing, and the results were satisfactory. Our hypothesis was confirmed for both remote diagnosis using real-time video and virtual slide systems, and also for teleconferencing using virtual slide systems with voice functionality. CONCLUSIONS: Our results demonstrate the feasibility of ultra-high-speed internet satellite networks for use in telepathology. Because communications satellites have less geographical and infrastructural requirements than landlines, ultra-high-speed internet satellite telepathology represents a major step toward alleviating regional disparity in the quality of medical care.

5.
Nanoscale Res Lett ; 8(1): 429, 2013 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-24134673

RESUMEN

We have characterized the binary LB films of merocyanine dye (MS) and arachidic acid (C20) before and after hydrothermal treatment (HTT), which is defined as a heat treatment under relative humidity of 100%, focusing on the morphology studied by bright field (BF) microscopy and fluorescence (FL) microscopy. BF microscopy observation has revealed that the as-deposited MS-C20 binary LB film is found to emit intense red fluorescence over the whole film area by 540-nm excitation. Since the surface image is almost featureless, it is considered that the crystallite sizes of J-aggregate are less than 10 µm. Interestingly, after HTT, round-shaped domains are observed in the LB systems, and the sizes are reaching 100 µm in diameter. Crystallites of J-aggregate, which are bluish in color and emit intense red fluorescence, tend to be in the round domains. We have observed two different types of domains, i.e., blue-rimmed domains and white-rimmed domains, which are postulated to be confined in the inner layers and located at the outermost layer, respectively. The thickness of the domains is equal to or less than that of the double layer of the MS-C20 mixed LB film, which is ca. 5.52 nm. The molecular order of MS in the J-aggregate is improved by the HTT process leading to the significant sharpening of the band shape together with the further red shift of the band (from 590 to 594 nm up to 597 to 599 nm). The reorganized J-band is considered to be 'apparently' isotropic owing to the random growth of the J-aggregate in the film plane. We consider that the lubrication effect by the presence of water molecules predominates in the HTT process.

6.
Pathol Int ; 62(12): 823-6, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23252872

RESUMEN

Mesenchymal chondrosarcoma (MC) is an extremely rare subtype of chondrosarcoma. A tumor specific fusion gene, HEY1-NCOA2 fusion, was recently identified in this tumor. The finding raises the possibility that the diagnosis of MC can be improved by examining the fusion gene. In the present study, we aimed to evaluate the efficacy of fluorescence in situ hybridization (FISH) in detecting HEY1-NCOA2 fusion for the diagnosis of MC. Specimens from 10 patients diagnosed with MC were used for the study. Dual-color FISH was performed using two different probes that specifically hybridize to HEY1 and NCOA2, respectively. Fusion signals were identified in all but two specimens, in which no signal was detected, presumably because of inadequate sample preparation. In accordance with results of a previous study, FISH analysis was highly sensitive in detecting HEY1-NCOA2 fusion in adequately prepared MC samples. The current study adds further support for the use of HEY1-NCOA2 fusion as a valid diagnostic marker for MC.


Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/análisis , Neoplasias Óseas/diagnóstico , Proteínas de Ciclo Celular/análisis , Condrosarcoma Mesenquimal/diagnóstico , Hibridación Fluorescente in Situ/métodos , Coactivador 2 del Receptor Nuclear/genética , Proteínas de Fusión Oncogénica/análisis , Adolescente , Adulto , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Neoplasias Óseas/genética , Proteínas de Ciclo Celular/genética , Condrosarcoma Mesenquimal/genética , Formaldehído , Humanos , Coactivador 2 del Receptor Nuclear/análisis , Proteínas de Fusión Oncogénica/genética , Adhesión en Parafina , Fijación del Tejido , Adulto Joven
7.
Pathol Int ; 62(1): 16-27, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22192800

RESUMEN

For the detection of chromosome translocations/chimeric genes and specific genetic abnormalities in soft tissue tumors, we conducted fluorescence in situ hybridization (FISH) analysis on 280 cases of soft tissue and other tumors using formalin-fixed paraffin-embedded tissue sections. The detection rate of the FISH split-signal was 84% (129/154 cases) for the translocation-associated soft tissue tumors, such as Ewing's sarcoma/primitive neuroectodermal tumor, synovial sarcoma, alveolar rhabdomyosarcoma, myxoid liposarcoma, clear cell sarcoma and so forth. Positive split-signals from EWSR1, SS18 and FOXO1A probes were detected in 3% (2/64) of various histological types of carcinoma, lymphoma, melanoma, meningioma and soft tissue tumors. In FISH using the INI1/CEP22 probe, the INI1 deletion signal was detected in 100% (9/9) of epithelioid sarcoma. In well-differentiated and dedifferentiated liposarcomas, detection of MDM2 amplification signals in FISH using the MDM2/CEP12 probe were both as high as 85% (11/13) and 100% (13/13), respectively. In other adipocytic and non-adipocytic tumors requiring differentiation from these types, detection was only 13% (5/39), and CEP12 polysomy was frequently detected. As these results demonstrate the high sensitivity and specificity of FISH, we concluded FISH to be a useful pathological diagnostic adjunct for definite and differential diagnosis of soft tissue tumors.


Asunto(s)
Hibridación Fluorescente in Situ , Neoplasias de los Tejidos Conjuntivo y Blando/genética , Sarcoma/genética , Translocación Genética , Adulto , Preescolar , Sondas de ADN , Femenino , Humanos , Liposarcoma Mixoide/diagnóstico , Liposarcoma Mixoide/genética , Masculino , Neoplasias de los Tejidos Conjuntivo y Blando/diagnóstico , Tumores Neuroectodérmicos/diagnóstico , Tumores Neuroectodérmicos/genética , Adhesión en Parafina , Rabdomiosarcoma/diagnóstico , Rabdomiosarcoma/genética , Sarcoma/diagnóstico , Sarcoma de Células Claras/diagnóstico , Sarcoma de Células Claras/genética , Sarcoma de Ewing/diagnóstico , Sarcoma de Ewing/genética , Sarcoma Sinovial/diagnóstico , Sarcoma Sinovial/genética , Sensibilidad y Especificidad , Adulto Joven
8.
Pathol Res Pract ; 207(6): 383-90, 2011 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-21620578

RESUMEN

Esophageal symptoms in mixed connective tissue disease (MCTD) have been investigated radiologically. We investigated the esophageal lesions in MCTD histopathologically, and analyzed relationships between these lesions and autoantibodies extracted from the serum of MCTD patients. Esophageal tissues from 27 MCTD patients submitted to autopsy were examined. We compared histopathological features of the esophagus in different wall layers from the mucosa, submucosa, and muscular layer to the adventitia, and in the upper, middle, and lower portions of esophagus. The most striking change observed was severe atrophy and occasional loss of smooth muscle cells in the muscular layer, followed by fibrosis. These muscular changes were particularly prominent in the inner layer of the lower esophagus. Immunohistochemically, degenerated muscular tissues of the esophagus were positive for anti-IgG and anti-C3 antibodies, but not for anti-IgM antibodies. IgG fractions extracted from three MCTD patients were immunohistochemically used to examine whether some antibodies in MCTD patients showed reactivity for esophageal components. The IgG fractions isolated from MCTD patients reacted with smooth muscle from non-connective tissue disease cases, suggesting that some serum antibodies may trigger esophageal changes. These findings suggest that esophageal lesions associated with clinical dysphagia in MCTD may be related to autoantibodies.


Asunto(s)
Trastornos de Deglución/patología , Esófago/patología , Enfermedad Mixta del Tejido Conjuntivo/patología , Músculo Liso/patología , Adolescente , Adulto , Anciano , Atrofia , Autoanticuerpos/sangre , Autopsia , Trastornos de Deglución/inmunología , Trastornos de la Motilidad Esofágica/inmunología , Trastornos de la Motilidad Esofágica/patología , Esófago/inmunología , Femenino , Fibrosis , Humanos , Inmunohistoquímica , Japón , Masculino , Persona de Mediana Edad , Enfermedad Mixta del Tejido Conjuntivo/inmunología , Membrana Mucosa/patología , Músculo Liso/inmunología , Adulto Joven
9.
Tohoku J Exp Med ; 223(4): 291-6, 2011 04.
Artículo en Inglés | MEDLINE | ID: mdl-21467828

RESUMEN

Terahertz (THz; 10(12) Hz) waves have a frequency from 0.1 to 10 THz between the visible light and microwave domains. THz waves are expected to be useful for analysis of the histological features, without any staining procedure that is an indispensable prerequisite for optical microscopy. It has been demonstrated that THz transmittances at cancer and normal tissues are different. However, spectroscopy that is currently used is applicable for imaging only small areas at fixed-wavelength. In this study, we have developed a spectrometer employing a gallium phosphide (GaP) THz-generator and applied it to examine large areas of tissue specimens using a wide range of wavelengths. We thus examined the whole areas of two paraffin sections (metastatic liver cancer and acute myocardial infarction) in a frequency range of 1 to 6 THz, and compared the THz images of ordinary paraffin sections with the histological features detected by microscopy. THz imaging showed striking contrasts between cancerous and non-cancerous regions at 3.7 THz. Likewise, the precise imaging was achieved in the infarct myocardium at 3.6 THz. Images of THz transmittances in optimal wavelength were well matched with HE histological features both in cancer and myocardial tissues. Cancer regions showed higher transmittance than non-cancerous regions in liver. Old scar regions showed low transmittance, and necrotic regions showed relatively higher transmittance than normal myocardial areas. Thus, THz imaging precisely reflects tissue conditions such as tumor, non-tumor tissues, tissue degeneration and fibrosis. The newly established THz spectroscopy would be useful for pathological diagnosis of routinely processed specimens.


Asunto(s)
Neoplasias Hepáticas/patología , Infarto del Miocardio/patología , Adhesión en Parafina , Espectroscopía de Terahertz/métodos , Diagnóstico por Imagen , Humanos
10.
Mod Rheumatol ; 21(4): 423-7, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21264487

RESUMEN

We report the autopsy results of a patient with systemic sclerosis with myositis lesions in the skeletal muscles and myocardium. A 69-year-old Japanese woman developed congestive heart failure and died due to respiratory failure with restrictive hypoventilation. The heart at autopsy showed dilated ventricular hypertrophy, and histopathology of the heart exhibited diffuse replacement fibrosis resembling the lesion of ischemic heart diseases in addition to patchy fibrosis around myocardial fibers suggesting post-myocarditis-like fibrosis.


Asunto(s)
Insuficiencia Cardíaca/diagnóstico , Esclerodermia Sistémica/diagnóstico , Anciano , Autopsia , Resultado Fatal , Femenino , Insuficiencia Cardíaca/patología , Humanos , Inmunohistoquímica , Miositis/diagnóstico , Miositis/patología , Insuficiencia Respiratoria/diagnóstico , Insuficiencia Respiratoria/mortalidad , Esclerodermia Sistémica/patología
11.
J Rheumatol ; 38(4): 730-7, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21239745

RESUMEN

OBJECTIVE: We analyzed 9 cases by immunohistochemical studies in order to elucidate the mechanisms of cartilage destruction in relapsing polychondritis (RP), which often involves the external auricle and respiratory tract through immunological disorder. METHODS: Cartilage tissues were obtained during surgical operations. Cell species in the granulation tissues, especially near the cartilage, were identified by cell-surface markers [CD3, CD4, CD8, CD20, CD45 (LCA), and CD68]. The proteolytic enzymes expressed in the cells in the perichondral granulation and in chondrocytes themselves were analyzed by immunohistochemical studies using anti-matrix metalloproteinase (MMP) -1, -3, -8, -9, and -13, and cathepsin D, K, L, and elastase antibodies. Apoptosis and nitric oxide (NO), an apoptosis-related factor, were also examined using ApopTag and antinitrotyrosine antibody, respectively. RESULTS: Among cell species that infiltrated in perichondral granulation, LCA, CD68 (monocytes/macrophages), and CD4 cells were dominant in number; MMP-8, MMP-9, and elastase were expressed only in the perichondral granulation; whereas MMP-3 and cathepsin K and L were detected in both chondrocytes and granulations. Out of 9 cases examined, 6 revealed apoptotic cells in excess of 50% of chondrocytes. There was a strong correlation between the number of apoptotic cells and the number of MMP-3-positive (r = 0.83) and cathepsin K-positive cells (r = 0.92). Abundant NO-expressing cells were observed in the chondrocytes in degenerated cartilage, similar to apoptosis. CONCLUSION: Cartilage destruction in polychondritis is induced not only by perichondral inflammation, but also by intrinsic factors expressed in chondrocytes themselves, including certain kinds of proteolytic enzymes and apoptosis.


Asunto(s)
Apoptosis/fisiología , Cartílago/patología , Condrocitos/patología , Péptido Hidrolasas/metabolismo , Policondritis Recurrente/enzimología , Policondritis Recurrente/patología , Adulto , Anciano , Anciano de 80 o más Años , Cartílago/citología , Femenino , Tejido de Granulación/patología , Humanos , Inflamación/patología , Masculino , Persona de Mediana Edad , Policondritis Recurrente/fisiopatología
12.
Hepatol Res ; 37(2): 158-65, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17300712

RESUMEN

A 65-year-old Japanese man was hospitalized because of acute hepatitis and severe cholestasis due to hepatitis E virus (HEV) infection combined with a drug reaction to a cold preparation. He died of disseminated intravascular coagulation and severe intestinal bleeding due to systemic cytomegalovirus reactivation following the development of severe eruptions with marked eosinophilia due to drug hypersensitivity to taurine and ursodeoxycholate preparations. The close interaction between viral infection or reactivation and drug hypersensitivity was considered as a pathophysiology in this case, which emphasizes the need for further study of the immunological mechanism of the interaction.

13.
AJNR Am J Neuroradiol ; 26(2): 421-3, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15709149

RESUMEN

Intraoral neurilemmoma is rare (only 1%), and the most common form is a unilobular tumor on the dorsum of the tongue in the patients in the 2nd and 3rd decades of life. Herein we describe the case of intraoral neurilemmoma in a 9-year-old girl complaining only of a sore throat. She had an exophytic multilobulated mass on the base of the tongue. MR imaging demonstrates the extension of the tumor and helps in the differential diagnosis. The signal intensity of the tumor is similar to that of neurilemmomas in the other sites.


Asunto(s)
Neurilemoma/diagnóstico , Neoplasias de la Lengua/diagnóstico , Niño , Femenino , Humanos
14.
Hum Pathol ; 35(6): 764-8, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15188145

RESUMEN

A 45-year-old woman presented with asymptomatic solid tumor in the lower right lobe of the lung. Histologically, the tumor comprised a monolayer of surface cells and round stromal cells displaying sclerotic areas. Immunohistochemical studies suggested a diagnosis of sclerosing hemangioma. Interestingly, morular lesions were also observed. Analyses of the gastrointestinal (GI) tract showed mild familial adenomatous polyposis (FAP) and numerous fundal gland polyps, indicating attenuated FAP (AFAP). All components of the sclerosing hemangioma displayed aberrant nuclear and cytoplasmic expression of beta-catenin. However, such findings were much weaker in adenomas of the GI tract and were barely observed in fundal gland polyps. These results strongly suggest an association between sclerosing hemangioma and the AFAP. To the best of our knowledge, this is only the second report of lung tumor associated with FAP and is the first describing an association with sclerosing hemangioma. A new category of FAP-associated lung tumors may be indicated.


Asunto(s)
Poliposis Adenomatosa del Colon/patología , Histiocitoma Fibroso Benigno/patología , Neoplasias Pulmonares/patología , Neoplasias Primarias Múltiples/patología , Poliposis Adenomatosa del Colon/metabolismo , Proteínas del Citoesqueleto/biosíntesis , Femenino , Histiocitoma Fibroso Benigno/metabolismo , Humanos , Inmunohistoquímica , Neoplasias Pulmonares/metabolismo , Persona de Mediana Edad , Neoplasias Primarias Múltiples/metabolismo , Transactivadores/biosíntesis , beta Catenina
15.
Tohoku J Exp Med ; 200(2): 103-9, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12962408

RESUMEN

Primary clear cell myoepithelial carcinoma (CCMC) is extremely rare. During the past twenty years, only one CCMC case has been reported. Here, a case of CCMC is reported. A 30-year-old woman became aware of an abnormal mass on the left breast, and quadrantectomy was performed. Microscopically, it consisted of tumor cells that had clear cytoplasm and showed an invasive growth pattern. Immunohistochemically, the tumor was positive for alpha-smooth muscle actin, S-100, partly positive for vimentin and epithelial membranous antigen. From these findings, the tumor was diagnosed as CCMC. Most of the clear cell myoepithelial tumors are probably misclassified in other examples. It is expected that the numbers of CCMC may be increased by routinely performing special stains and immunohistochemical stains, even without ultrastructual study.


Asunto(s)
Neoplasias de la Mama/patología , Mioepitelioma/patología , Actinas/análisis , Adulto , Biomarcadores de Tumor/análisis , Neoplasias de la Mama/química , Neoplasias de la Mama/cirugía , Femenino , Humanos , Inmunohistoquímica , Mastectomía Segmentaria , Mucina-1/análisis , Mioepitelioma/química , Mioepitelioma/cirugía , Proteínas S100/análisis , Vimentina/análisis
16.
Genes Cells ; 8(12): 1019-27, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14750956

RESUMEN

BACKGROUND: Invadopodia are membrane protrusions into the extracellular matrix by aggressive tumour cells. These structures are associated with sites of matrix degradation and invasiveness of malignant tumour cells in an in vitro fibronectin degradation/invasion assay. The Rho family small G proteins, consisting of the Rho, Rac and Cdc42 subfamilies, are implicated in various cell functions, such as cell shape change, adhesion, and motility, through reorganization of the actin cytoskeleton. We studied the roles of the Rho family small G proteins in invadopodia formation. RESULTS: We first demonstrated that invadopodia of RPMI7951 human melanoma cells extended into the matrix substratum on a vertical view using a laser scanning confocal microscope system. We confirmed that invadopodia were rich in actin filaments (F-actin) and visualized clearly with F-actin staining on a vertical view as well as on a horizontal view. We then studied the roles of Rho, Rac, and Cdc42 in invasiveness of the same cell line. In the in vitro fibronectin degradation/invasion assay, a dominant active mutant of Cdc42 enhanced dot-like degradation, whereas a dominant active mutant of Rac enhanced diffuse-type degradation. Furthermore, frabin, a GDP/GTP exchange protein for Cdc42 with F-actin-binding activity, enhanced both dot-like and diffuse-type degradation. However, a dominant active mutant of Rho did not affect the fibronectin degradation. Moreover, inhibition of phosphatidylinositol-3 kinase (PI3K) disrupted the Rac and Cdc42-dependent actin structures and blocked the fibronectin degradation. CONCLUSION: These results suggest that Cdc42 and Rac play important roles in fibronectin degradation and invasiveness in a coordinate manner through the frabin-Cdc42/Rac-PI3K signalling pathway.


Asunto(s)
Melanoma/patología , Proteína de Unión al GTP cdc42/fisiología , Proteínas de Unión al GTP rac/fisiología , Actinas/análisis , Línea Celular Tumoral , Estructuras de la Membrana Celular/química , Estructuras de la Membrana Celular/ultraestructura , Tamaño de la Célula , Fibronectinas/metabolismo , Factores de Intercambio de Guanina Nucleótido/fisiología , Humanos , Melanoma/metabolismo , Melanoma/ultraestructura , Invasividad Neoplásica , Fosfatidilinositol 3-Quinasas/metabolismo
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