Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 435
Filtrar
1.
J Phys Condens Matter ; 35(28)2023 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-37015243

RESUMEN

We report the first study of electrical resistivity, magnetization, and specific heat on YbCo2. The measurements on a single-phased sample of YbCo2bring no evidence of magnetic ordering down to 0.3 K in a zero magnetic field. The manifestations of low Kondo temperature are observed. The specific heat value divided by temperature,C/T, keeps increasing logarithmically beyond 7 J/mol K2with decreasing temperature down to 0.3 K without no sign of magnetic ordering, suggesting a very large electronic specific heat. Analysis of the magnetic specific heat indicates that the large portion of the low-temperature specific heat is not explained simply by the low Kondo temperature but is due to the strong intersite magnetic correlation in both the 3dand 4felectrons. Temperature-dependent measurements under static magnetic fields up to 7 T are carried out, which show the evolution of field-induced transition above 2 T. The transition temperature increases with increasing field, pointing to a ferromagnetic character. The extrapolation of the transition temperature to zero field suggests that YbCo2is in the very proximity of the quantum critical point. These results indicate that in the unique case of YbCo2, the itinerant electron magnetism of Co 3d-electrons and the Kondo effect within the vicinity of quantum criticality of Yb 4f-local moments can both play a role.

2.
Nat Commun ; 13(1): 1817, 2022 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-35361763

RESUMEN

Magnetic refrigeration (MR) is a key technique for hydrogen liquefaction. Although the MR has ideally higher performance than the conventional gas compression technique around the hydrogen liquefaction temperature, the lack of MR materials with high magnetic entropy change in a wide temperature range required for the hydrogen liquefaction is a bottle-neck for practical applications of MR cooling systems. Here, we show a series of materials with a giant magnetocaloric effect (MCE) in magnetic entropy change (-∆Sm > 0.2 J cm-3K-1) in the Er(Ho)Co2-based compounds, suitable for operation in the full temperature range required for hydrogen liquefaction (20-77 K). We also demonstrate that the giant MCE becomes reversible, enabling sustainable use of the MR materials, by eliminating the magneto-structural phase transition that leads to deterioration of the MCE. This discovery can lead to the application of Er(Ho)Co2-based alloys for the hydrogen liquefaction using MR cooling technology for the future green fuel society.

3.
Clin Pharmacol Ther ; 102(6): 897-902, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28795399

RESUMEN

The goal of pharmacogenomics research is to discover genetic polymorphisms that underlie variation in drug response. Increasingly, pharmacogenomics research involves large numbers of patients and the application of new technologies and methodologies to enable discovery. The Pharmacogenomics Research Network (PGRN) has become a community-driven network of investigators spanning scientific and clinical disciplines. Here, we highlight the activities and types of resources that enable PGRN members to enhance and drive basic and translational research in pharmacogenomics.


Asunto(s)
Investigación Biomédica/organización & administración , Farmacogenética/organización & administración , Medicina de Precisión/métodos , Investigación Biomédica Traslacional/organización & administración , Humanos
4.
Cell Death Differ ; 22(9): 1437-50, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25613378

RESUMEN

Adenine nucleotide translocases (ANTs) transport ADP and ATP through mitochondrial inner membrane, thus playing an essential role for energy metabolism of eukaryotic cells. Mice have three ANT paralogs, Ant1 (Slc25a4), Ant2 (Slc25a5) and Ant4 (Slc25a31), which are expressed in a tissue-dependent manner. While knockout mice have been characterized with Ant1 and Ant4 genes, which resulted in exercise intolerance and male infertility, respectively, the role of the ubiquitously expressed Ant2 gene in animal development has not been fully demonstrated. Here, we generated Ant2 hypomorphic mice by targeted disruption of the gene, in which Ant2 expression is largely depleted. The mice showed apparently normal embryonic development except pale phenotype along with a reduced birth rate. However, postnatal growth was severely retarded with macrocytic anemia, B lymphocytopenia, lactic acidosis and bloated stomach, and died within 4 weeks. Ant2 depletion caused anemia in a cell-autonomous manner by maturation arrest of erythroid precursors with increased reactive oxygen species and premature deaths. B-lymphocyte development was similarly affected by Ant2 depletion, and splenocytes showed a reduction in maximal respiration capacity and cellular ATP levels as well as an increase in cell death accompanying mitochondrial permeability transition pore opening. In contrast, myeloid, megakaryocyte and T-lymphocyte lineages remained apparently intact. Erythroid and B-cell development may be particularly vulnerable to Ant2 depletion-mediated mitochondrial dysfunction and oxidative stress.


Asunto(s)
Translocador 2 del Nucleótido Adenina/deficiencia , Linfocitos B/citología , Eritrocitos/citología , Eritropoyesis/fisiología , Linfopoyesis/fisiología , Translocasas Mitocondriales de ADP y ATP/metabolismo , Translocador 2 del Nucleótido Adenina/genética , Translocador 2 del Nucleótido Adenina/metabolismo , Adenosina Trifosfato/metabolismo , Anemia/genética , Anemia/metabolismo , Animales , Linfocitos B/metabolismo , Eritrocitos/metabolismo , Eritropoyesis/genética , Femenino , Técnicas de Inactivación de Genes , Trastornos del Crecimiento/genética , Trastornos del Crecimiento/metabolismo , Humanos , Linfopoyesis/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias/genética , Mitocondrias/metabolismo
5.
J Oral Rehabil ; 42(2): 83-9, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25256380

RESUMEN

Bruxism contributes to the development of temporomandibular disorders as well as causes dental problems. Although it is an important issue in clinical dentistry, no treatment approaches have been proven effective. This study aimed to use electromyogram (EMG) biofeedback (BF) training to improve awake bruxism (AB) and examine its effect on sleep bruxism (SB). Twelve male participants (mean age, 26·8 ± 2·5 years) with subjective symptoms of AB or a diagnosis of SB were randomly divided into BF (n = 7) and control (CO, n = 5) groups to undergo 5-h daytime and night-time EMG measurements for three consecutive weeks. EMG electrodes were placed over the temporalis muscle on the habitual masticatory side. Those in the BF group underwent BF training to remind them of the occurrence of undesirable clenching activity when excessive EMG activity of certain burst duration was generated in week 2. Then, EMGs were recorded at week 3 as the post-BF test. Those in the CO group underwent EMG measurement without any EMG BF training throughout the study period. Although the number of tonic EMG events did not show statistically significant differences among weeks 1-3 in the CO group, events in weeks 2 and 3 decreased significantly compared with those in week 1, both daytime and night-time, in the BF group (P < 0·05, Scheffé's test). This study results suggest that EMG BF to improve AB tonic EMG events can also provide an effective approach to regulate SB tonic EMG events.


Asunto(s)
Biorretroalimentación Psicológica/métodos , Bruxismo/terapia , Electromiografía , Dolor Facial/etiología , Dolor Facial/prevención & control , Músculos Masticadores/fisiopatología , Trastornos de la Articulación Temporomandibular/etiología , Adulto , Bruxismo/complicaciones , Bruxismo/psicología , Humanos , Masculino , Contracción Muscular , Dimensión del Dolor , Trastornos de la Articulación Temporomandibular/prevención & control
6.
Microsc Microanal ; 18(5): 1030-6, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23058452

RESUMEN

Adenosine triphosphate (ATP) is a well-known energy source for muscle contraction. In this study, to visualize localization of ATP, a luciferin-luciferase reaction (LLR) was performed in mouse skeletal muscle with an "in vivo cryotechnique" (IVCT). First, to confirm if ATP molecules could be trapped and detected after glutaraldehyde (GA) treatment, ATP was directly attached to glass slides with GA, and LLR was performed. The LLR was clearly detected as an intentional design of the ATP attachment. The intensity of the light unit by LLR was correlated with the concentration of the GA-treated ATP in vitro. Next, LLR was evaluated in mouse skeletal muscles with IVCT followed by freeze-substitution fixation (FS) in acetone-containing GA. In such tissue sections the histological structure was well maintained, and the intensity of LLR in areas between muscle fibers and connective tissues was different. Moreover, differences in LLR among muscle fibers were also detected. For the IVCT-FS tissue sections, diaminobenzidine (DAB) reactions were clearly detected in type I muscle fibers and erythrocytes in capillaries, which demonstrated flow shape. Thus, it became possible to perform microscopic evaluation of the numbers of ATP molecules in the mouse skeletal muscles with IVCT, which mostly reflect living states.


Asunto(s)
Adenosina Trifosfato/análisis , Luciferina de Luciérnaga/metabolismo , Substitución por Congelación/métodos , Luciferasas/metabolismo , Músculo Esquelético/química , Adenosina Trifosfato/metabolismo , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Músculo Esquelético/citología , Músculo Esquelético/metabolismo
7.
Phys Rev Lett ; 108(21): 219701; author reply 219702, 2012 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-23003315
8.
Theriogenology ; 78(6): 1243-51.e1-2, 2012 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-22898023

RESUMEN

The hypothesis was tested that the pluripotency of the inner cell mass (ICM) of the bovine embryo is enhanced by the glycogen synthase kinase-3ß inhibitor CHIR99021 and the MAPK1 and MAPK3 inhibitor PD032591. Treatment with the two inhibitors from Days 6 to 8 after insemination increased blastocyst steady state concentrations of mRNA for NANOG (P < 0.05) and SOX2 (P = 0.055) and tended to decrease (P = 0.09) expression of GATA6. To evaluate pluripotency, the inner cell mass was isolated by immunosurgery at Day 8, seeded on a feeder layer of bovine embryonic fibroblasts, and cultured in the presence of the inhibitors. Ten of 52 (19%) ICM from control embryos had primary outgrowth formation vs. 23 of 50 (46%) of the ICM from embryos cultured with inhibitors (P < 0.01). For ICM outgrowths from embryos cultured without inhibitors, colonies either did not persist through Passage 2 or became differentiated. In contrast, for the inhibitor group, four colonies survived beyond Passage 2, and one line persisted for 19 passages. This cell line possessed alkaline phosphatase activity, expressed several genes characteristically expressed in pluripotent cells, and differentiated into embryoid bodies when cultured in the absence of the signal transduction inhibitors and the feeder layer. Propagation of the cells was difficult due to slow growth and inefficiency in survival through each passage. In conclusion, exposure to inhibitors during the morula-blastocyst transition facilitated formation of self-renewing pluripotent cell lines from bovine blastocysts.


Asunto(s)
Masa Celular Interna del Blastocisto/citología , Blastocisto/fisiología , Bovinos/embriología , Técnicas de Cultivo de Embriones/veterinaria , Mórula/fisiología , Células Madre Pluripotentes/citología , Animales , Blastocisto/química , Separación Celular/veterinaria , Colforsina/farmacología , Inhibidores Enzimáticos/farmacología , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Glucógeno Sintasa Quinasa 3 beta , Proteínas de Homeodominio/genética , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 3 Activada por Mitógenos/antagonistas & inhibidores , Piridinas/farmacología , Pirimidinas/farmacología , ARN Mensajero/análisis , Factores de Transcripción SOXB1/genética
9.
J Phys Condens Matter ; 24(7): 075602, 2012 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-22301486

RESUMEN

Soft resonant x-ray Bragg diffraction (SRXD) at the Ho M4,5 edges has been used to study Ho 4f multipoles in the combined magnetic and orbitally ordered phase of HoB2C2. A full description of the energy dependence for both σ and π incident x-rays at two different azimuthal angles, as well as the ratio I(σ)/I(π) as a function of azimuthal angle for a selection of energies, allows a determination of the higher order multipole moments of rank 1 (dipole) to 6 (hexacontatetrapole). The Ho 4f multipole moments have been estimated, indicating a dominant hexadecapole (rank 4) order with an almost negligible influence from either the dipole or the octupole magnetic terms. The analysis incorporates both the intra-atomic magnetic and quadrupolar interactions between the 3d core and 4f valence shells as well as the interference of contributions to the scattering that behave differently under time reversal. Comparison of SRXD, neutron diffraction and non-resonant x-ray diffraction shows that the magnetic and quadrupolar order parameters are distinct. The (00½) component of the magnetic order exhibits a Brillouin type increase below the orbital ordering temperature T(Q), while the quadrupolar order increases more sharply. We conclude that the quadrupolar interaction is strong, but quadrupolar order only occurs when the magnetic order gives rise to a quasi-doublet ground state, which results in a lock-in of the orbitals at T(Q).

10.
Oncogene ; 31(25): 3098-110, 2012 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-22020339

RESUMEN

Inactivation of the von Hippel-Lindau (VHL) tumor-suppressor gene causes both hereditary and sporadic clear-cell renal-cell carcinoma (ccRCC). Although the best-characterized function of the VHL protein (pVHL) is regulation of hypoxia-inducible factor-α (HIFα), pVHL also controls the development of pheochromocytoma through HIF-independent pathways by regulating JunB. However, it is largely unknown how these pathways contribute to the development and progression of ccRCC. In the present study, we confirmed that JunB was upregulated in VHL-defective ccRCC specimens by immunostaining. Short-hairpin RNA (shRNA)-mediated knockdown of JunB in 786-O and A498 VHL null ccRCC cells suppressed their invasiveness. In addition, JunB knockdown significantly repressed tumor growth and microvessel density in xenograft tumor assays. Conversely, forced expression of wild-type, but not dimerization-defective, JunB in a VHL-restored 786-O subclone promoted invasion in vitro and tumor growth and vessel formation in vivo. Quantitative PCR array analysis revealed that JunB regulated multiple genes relating to tumor invasion and angiogenesis such as matrix metalloproteinase-2 (MMP-2), MMP-9 and chemokine (C-C motif) ligand-2 (CCL2) in 786-O cells. JunB knockdown in these cells reduced the proteolytic activity of both MMPs in gelatin zymography and the amount of CCL2 in the culture supernatant. Moreover, shRNA-mediated knockdown of MMP-2 or inhibition of CCL2 activity with a neutralizing antibody repressed xenograft tumor growth and angiogenesis. Collectively, these results suggest that JunB promotes tumor invasiveness and enhances angiogenesis in VHL-defective ccRCCs.


Asunto(s)
Carcinoma de Células Renales/metabolismo , Neoplasias Renales/metabolismo , Neovascularización Patológica/metabolismo , Proteínas Proto-Oncogénicas c-jun/metabolismo , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/metabolismo , Animales , Carcinoma de Células Renales/irrigación sanguínea , Carcinoma de Células Renales/patología , Humanos , Neoplasias Renales/irrigación sanguínea , Neoplasias Renales/patología , Ratones , Invasividad Neoplásica , Trasplante de Neoplasias , Proteínas Proto-Oncogénicas c-jun/genética , Trasplante Heterólogo
11.
Cancer Gene Ther ; 18(8): 571-8, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21660062

RESUMEN

Replication-competent retrovirus (RCR) vectors have been shown to achieve significantly enhanced tumor transduction efficiency and therapeutic efficacy in various cancer models. In the present study, we investigated RCR vector-mediated prodrug activator gene therapy for the treatment of malignant mesothelioma, a highly aggressive tumor with poor prognosis. RCR-GFP vector expressing the green fluorescent protein marker gene successfully infected and efficiently replicated in human malignant mesothelioma cell lines, as compared with non-malignant mesothelial cells in vitro. In mice with pre-established subcutaneous tumor xenografts, RCR-GFP vector showed robust spread throughout entire tumor masses after intratumoral administration. Next, RCR-cytosine deaminase (RCR-CD), expressing the yeast CD prodrug activator gene, showed efficient transmission of the prodrug activator gene associated with replicative spread of the virus, resulting in efficient killing of malignant mesothelioma cells in a prodrug 5-fluorocytosine (5FC)-dose dependent manner in vitro. After a single intratumoral injection of RCR-CD followed by intraperitoneal administration of 5FC, RCR vector-mediated prodrug activator gene therapy achieved significant inhibition of subcutaneous tumor growth, and significantly prolonged survival in the disseminated peritoneal model of malignant mesothelioma. These data indicate the potential utility of RCR vector-mediated prodrug activator gene therapy in the treatment of malignant mesothelioma.


Asunto(s)
Terapia Genética/métodos , Mesotelioma/terapia , Mesotelioma/virología , Viroterapia Oncolítica/métodos , Retroviridae/genética , Adulto , Animales , Línea Celular Tumoral , Citosina Desaminasa/genética , Citosina Desaminasa/metabolismo , Modelos Animales de Enfermedad , Femenino , Flucitosina/administración & dosificación , Flucitosina/farmacocinética , Humanos , Masculino , Mesotelioma/genética , Mesotelioma/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Profármacos/administración & dosificación , Profármacos/farmacocinética , Retroviridae/fisiología , Análisis de Supervivencia , Transducción Genética , Replicación Viral
12.
J Dent Res ; 88(7): 633-8, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19605880

RESUMEN

Interleukin (IL)-23 is an essential cytokine involved in expansion of the Th17 lineage, which is associated with many immune-related destructive tissue diseases. We hypothesized that the IL-23-induced Th17 pathway plays a role in periodontal pathology and examined the expression of cytokines, and related molecules, in periodontal lesions and control sites. IL-23 and IL-12 were expressed at significantly higher levels in periodontal lesions than in control sites. However, the relative expression of the IL-23 receptor compared with the IL-12 receptor beta2 was significantly higher in periodontal lesions. Moreover, IL-17 expression was significantly higher in periodontal lesions, especially in the tissue adjacent to bone destruction, than in control sites. There was no significant difference in the expression levels of IFN-gamma, an important cytokine inhibiting differentiation toward the Th17 pathway, between periodontal lesions and control sites. Together, these results suggest that the IL-23-induced Th17 pathway is stimulated in inflammatory periodontal lesions.


Asunto(s)
Linfocitos T CD4-Positivos/metabolismo , Periodontitis Crónica/inmunología , Periodontitis Crónica/metabolismo , Interleucina-17/biosíntesis , Interleucina-23/biosíntesis , Estudios de Casos y Controles , Femenino , Expresión Génica , Humanos , Inmunohistoquímica , Interferón gamma/biosíntesis , Interleucina-12/biosíntesis , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Receptores de Interleucina/biosíntesis , Receptores de Interleucina-12/biosíntesis
13.
Histol Histopathol ; 24(6): 717-28, 2009 06.
Artículo en Inglés | MEDLINE | ID: mdl-19337970

RESUMEN

The transport mechanism of soluble molecules throughout the interstitial matrix is closely associated with human tumor behavior in vivo. However, the examination of soluble components in histological architectures has been hampered by artifacts caused during conventional tissue preparation. In this study, the immunodistribution of intrinsic and extrinsic serum components in tumor tissues was examined in xenografted human tumor cells using 'in vivo cryotechnique' (IVCT) and cryobiopsy, where target tissues are directly cryofixed in vivo. Human lung cancer cells were subcutaneously injected into the dorsal flank of nude mice, and paraffin sections and cryosections of produced tumors were prepared with different methods. Immunolocalization of serum proteins, including albumin, immunoglobulin G (IgG) and IgM, as well as intravenously injected bovine serum albumin (BSA) was examined. Their immunodistribution was more clearly observed in the interstitium by both IVCT and cryobiopsy than conventional methods. IgM was immunolocalized within blood vessels, whereas albumin and IgG were observed in the tumor interstitium. Moreover, intravenously injected bovine serum albumin exhibited leakage from the blood capillaries into surrounding connective tissues in 24 h, but it gradually diffused to the interstitium of the tumor masses during 3 days. These results suggest that molecular leakage from blood capillaries varies significantly in different areas of developing tumors, and that small serum proteins, but not large ones, were abundantly immunolocalized in the tumor interstitium. Both IVCT and cryobiopsy were found to be useful for immunohistochemical studies of soluble molecules in tumors with blood circulation, and may therefore be helpful for further histopathological analyses.


Asunto(s)
Proteínas Sanguíneas/metabolismo , Neoplasias Experimentales/metabolismo , Fijación del Tejido/métodos , Animales , Biopsia , Permeabilidad Capilar , Criopreservación , Técnica del Anticuerpo Fluorescente , Humanos , Inmunohistoquímica , Masculino , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Trasplante Heterólogo
15.
Rev Sci Instrum ; 79(12): 124301, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19123582

RESUMEN

We have studied the micro total analysis system as a blood test. A microfluidic device with a three-pronged microchannel and artificial capillary vessels was fabricated. The microchannel is to transport blood, focus blood cells, and line them up. The vessels are to observe red blood cell deformation. An excimer laser was used to form grooves and so on. Numbers of thermosetting resin film and fluororesin were piled up on a cover glass. A laser fabricated part of the channel at the each film every lamination, and then a three-dimensional structure microchannel was fabricated. The channel sizes have widths of 50-150 microm and depths of 45 mum. Through holes used as artificial capillary vessels are made in the fluororesin having a minimum diameter of 5 microm and a length of 100 microm. As blood and a physiological saline are injected into the microchannel, the device stands upward facing the channel, and blood cells go into the vessels by the force of gravity and sheath flow of the saline. By gravity various groove patterns were made changing the width and length for measurement of blood focusing. Moreover, the red blood cell deformation was observed in the vessels with a microscope.

16.
Histol Histopathol ; 23(3): 297-307, 2008 03.
Artículo en Inglés | MEDLINE | ID: mdl-18072087

RESUMEN

Immunoglobulin A (IgA) nephropathy shows great variability regarding the histological features of the lesions of human renal glomeruli. In the present study, the quick-freezing and deep-etching (QF-DE) method was used to analyze the glomerular ultrastructure of biopsied kidney tissues from children with IgA nephropathy. Biopsied renal tissues were routinely prepared for light microscopy, immunofluorescence microscopy, conventional electron microscopy, and replica electron microscopy. The three-dimensional ultrastructure of glomeruli of the kidney was clearly observed by using the QF-DE method. Three layers of glomerular basement membranes, i.e., middle, inner and outer layers, were clearly detected in the replica electron micrographs. The middle layer was 343.0+/-24.2 nm (n=20) in width and formed polygonal meshwork structures. We also observed slit diaphragms, electron-dense mesangial deposits, and increased amounts of mesangial matrix and foot process effacement. Many delicate filaments were found to be distributed from the apical to the bottom portions between neighboring foot processes. The ultrastructural difference between the replica electron micrographs and conventional electron micrographs was found to be especially marked in the appearance of foot processes and connecting filaments between the neighboring foot processes. The examination of extracellular matrix changes, as revealed at high resolution by the QF-DE method, gave us some morphofunctional information relevant to the mechanism of proteinuria with IgA nephropathy.


Asunto(s)
Capilares/ultraestructura , Glomerulonefritis por IGA/patología , Glomérulos Renales/irrigación sanguínea , Glomérulos Renales/ultraestructura , Adolescente , Membrana Basal/ultraestructura , Biopsia , Capilares/patología , Comunicación Celular , Niño , Citoesqueleto/patología , Citoesqueleto/ultraestructura , Endotelio Vascular/patología , Endotelio Vascular/ultraestructura , Femenino , Grabado por Congelación/métodos , Humanos , Glomérulos Renales/patología , Masculino , Células Mesangiales/patología , Células Mesangiales/ultraestructura , Microscopía Electrónica/métodos , Podocitos/patología , Podocitos/ultraestructura
17.
Histol Histopathol ; 22(11): 1281-90, 2007 11.
Artículo en Inglés | MEDLINE | ID: mdl-17647200

RESUMEN

Various microscopic methods have been used to analyze the morphology and molecular distribution of cells and tissues. Using conventional procedures, however, ischemic or anoxic artifacts are inevitably caused by tissue-resection or perfusion-fixation. The in vivo cryotechnique (IVCT) was developed to overcome these problems, and was found to be useful with light microscopy for analyses of the distribution of water-soluble molecules without anoxic effects at high time resolution. But there are limitations to the application of IVCT, such as exposure of target organs of living small animals and immunoreactivity of lipid-soluble molecules owing to freeze-substitution with acetone. Recently, a new cryotechnique called "cryobiopsy" has been developed, which enables one to obtain tissue specimens of large animals including humans without ischemia or anoxia, and has almost the same technical advantages as IVCT. Both IVCT and cryobiopsy complement other live-imaging techniques, and are useful for not only the morphological observation of cells and tissues under normal conditions, but also the preservation of all components in frozen tissue specimens. Therefore, morphofunctional information in vivo would be obtained by freeze-substituion for light or electron microscopy, and also by other analytical methods, such as freeze-fracture replication, X-ray microanalyses, or Raman microscopy. Considering the merits of both IVCT and cryobiopsy, their application should be expanded into other microscopic fields and also from experimental animal studies to clinical medicine.


Asunto(s)
Biopsia/métodos , Microscopía por Crioelectrón , Substitución por Congelación/métodos , Animales , Microscopía por Crioelectrón/métodos , Microanálisis por Sonda Electrónica , Humanos
18.
Astrobiology ; 7(1): 185-207, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17407407

RESUMEN

Atmospheric erosion of CO2-rich Earth-size exoplanets due to coronal mass ejection (CME)-induced ion pick up within close-in habitable zones of active M-type dwarf stars is investigated. Since M stars are active at the X-ray and extreme ultraviolet radiation (XUV) wave-lengths over long periods of time, we have applied a thermal balance model at various XUV flux input values for simulating the thermospheric heating by photodissociation and ionization processes due to exothermic chemical reactions and cooling by the CO2 infrared radiation in the 15 microm band. Our study shows that intense XUV radiation of active M stars results in atmospheric expansion and extended exospheres. Using thermospheric neutral and ion densities calculated for various XUV fluxes, we applied a numerical test particle model for simulation of atmospheric ion pick up loss from an extended exosphere arising from its interaction with expected minimum and maximum CME plasma flows. Our results indicate that the Earth-like exoplanets that have no, or weak, magnetic moments may lose tens to hundreds of bars of atmospheric pressure, or even their whole atmospheres due to the CME-induced O ion pick up at orbital distances

Asunto(s)
Astronomía , Planetas , Fenómenos Astronómicos , Exobiología , Medio Ambiente Extraterrestre , Calor , Iones , Simulación del Espacio , Rayos Ultravioleta , Rayos X
19.
Histol Histopathol ; 22(2): 137-45, 2007 02.
Artículo en Inglés | MEDLINE | ID: mdl-17149686

RESUMEN

Immunohistochemical analyses on local distributions of serum proteins in living mouse kidneys are usually difficult to examine with conventional preparation methods. By using our "in vivo cryotechnique" combined with freeze-substitution, we have checked immunolocalizations of the serum proteins in nephrons of bovine serum albumin (BSA)-overload mice, and compared them with those obtained by the conventional preparation methods. In two days of daily BSA-injected mice, the immunolocalization of BSA could be observed in Bowman's space and urinary tubules with their overt proteinuria, where another endogenous mouse albumin was similarly immunolocalized. The leakage of BSA and mouse albumin in Bowman's space and their reabsorption into proximal tubules were detected in 55% of nephrons, where no leakage of immunoglobulin G1 (IgG1) was detected. However, the leakage of IgG1, in addition to BSA and mouse albumin, was detected in the other nephrons. By carefully examining immunolocalizations of BSA and IgG1, they were obviously different from those obtained by the conventional preparation methods without normal blood circulation into the kidneys. The immunolocalizations of both BSA and mouse serum proteins could be directly analyzed with the "in vivo cryotechnique", suggesting that functional damage to glomerular filtration barriers are different at early stages of the BSA-overload mouse model, depending on each nephron of living mice.


Asunto(s)
Albuminuria/orina , Proteínas Sanguíneas/metabolismo , Substitución por Congelación/métodos , Técnicas para Inmunoenzimas/métodos , Nefronas/metabolismo , Albúmina Sérica Bovina/farmacología , Albuminuria/inducido químicamente , Animales , Bovinos , Modelos Animales de Enfermedad , Femenino , Ratones , Ratones Endogámicos C57BL , Nefronas/efectos de los fármacos , Nefronas/patología , Albúmina Sérica Bovina/orina
20.
Undersea Hyperb Med ; 33(1): 63-8, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16602258

RESUMEN

Hyperbaria reportedly affects the immune system, but the role of psychological factors arising from confinement has not been taken into consideration. We investigated the immune changes in 4 subjects exposed to a 9-day simulated 30-m (400-kPa) nitrogen-oxygen (nitrox) saturation dive, and compared the results with those of our previous study that showed immune and mood changes in normobaric confinement. Blood samples were taken before, during, and after the dive or confinement, and activated with an anti-CD2 agonistic antibody. The percentages of granulocytes, natural killer (NK) cells, and cells positive for CD69, an early activation marker, were analyzed by flow cytometry. Reduction of CD69 expression percentage was observed under both hyperbaric and normobaric conditions. Percentages of innate immune cells, such as granulocytes and NK cells decreased or remained mostly unchanged, contrasting with our previous study, which demonstrated increases in both percentages coordinate with mood improvement. We conclude that these changes may have been triggered by suppression of sympathetic nerve activity that occurs in 30-m nitrox saturation hyperbaria.


Asunto(s)
Afecto , Buceo/psicología , Sistema Inmunológico/fisiología , Nitrógeno/administración & dosificación , Oxígeno/administración & dosificación , Adulto , Antígenos CD/análisis , Antígenos de Diferenciación de Linfocitos T/análisis , Espacios Confinados , Buceo/fisiología , Granulocitos/citología , Humanos , Inmunidad Celular/fisiología , Células Asesinas Naturales/citología , Lectinas Tipo C , Recuento de Leucocitos , Masculino
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA