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1.
BMC Cancer ; 19(1): 912, 2019 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-31510956

RESUMEN

BACKGROUND: Interaction between cancer cells and fibroblasts mediated by extracellular matrix metalloproteinase inducer (emmprin, CD147) is important in the invasion and proliferation of cancer cells. However, the exact mechanism of emmprin mediated stimulation of matrix metalloprotease-2 (MMP-2) production from fibroblasts has not been elucidated. Our previous studies using an inhibitory peptide against emmprin suggested the presence of a molecule on the cell membrane which forms a complex with emmprin. Here we show that CD73 expressed on fibroblasts interacts with emmprin and is a required factor for MMP-2 production in co-cultures of sarcoma cells with fibroblasts. METHODS: CD73 along with CD99 was identified by mass spectrometry analysis as an emmprin interacting molecule from a co-culture of cancer cells (epithelioid sarcoma cell line FU-EPS-1) and fibroblasts (immortalized fibroblasts cell line ST353i). MMP-2 production was measured by immunoblot and ELISA. The formation of complexes of CD73 with emmprin was confirmed by immunoprecipitation, and their co-localization in tumor cells and fibroblasts was shown by fluorescent immunostaining and proximity ligation assays. RESULTS: Stimulated MMP-2 production in co-culture of cancer cells and fibroblasts was completely suppressed by siRNA knockdown of CD73, but not by CD99 knockdown. MMP-2 production was not suppressed by CD73-specific enzyme inhibitor (APCP). However, MMP-2 production was decreased by CD73 neutralizing antibodies, suggesting that CD73-mediated suppression of MMP-2 production is non-enzymatic. In human epithelioid sarcoma tissues, emmprin was immunohistochemically detected to be mainly expressed in tumor cells, and CD73 was expressed in fibroblasts and tumor cells: emmprin and CD73 were co-localized predominantly on tumor cells. CONCLUSION: This study provides a novel insight into the role of CD73 in emmprin-mediated regulation of MMP-2 production.


Asunto(s)
5'-Nucleotidasa/metabolismo , Basigina/metabolismo , Metaloproteinasa 2 de la Matriz/metabolismo , Biomarcadores , Línea Celular Tumoral , Técnicas de Cocultivo , Fibroblastos , Proteínas Ligadas a GPI/metabolismo , Humanos , Inmunohistoquímica , Espectrometría de Masas , Modelos Biológicos , Proteómica/métodos
2.
J Chem Phys ; 151(24): 244903, 2019 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-31893896

RESUMEN

The expressions for the minimal work of aggregate formation as a function of the aggregation number and monomer concentration for a system with a limited number of monomers and a fixed volume have additional terms in comparison with a bulk metastable phase. The role of these terms has been analyzed in the case of droplet homogeneous nucleation and micellization in a nonionic surfactant solution. The appearance of the potential well and direct and reversal aggregation barriers in such systems and their dependence on the system parameters and monomer concentration have been considered and compared.

3.
Metab Brain Dis ; 31(4): 909-15, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27131802

RESUMEN

Hepatic encephalopathy (HE) is a late complication of liver cirrhosis and is clearly associated with poor outcomes. Chronic liver insufficiency leads to progressive muscle wasting, impairing ammonia metabolism and thus increasing the risk for HE. Given the association between lean mass and adductor pollicis muscle thickness (APMT), it has been used to predict outcome and complications in many conditions, but not yet in cirrhotic patients. Therefore, this article aimed to study the association between HE manifestations and measures related to muscle mass and strength. This cross-sectional study included 54 cirrhotic outpatients with HE varying from subclinical to grade II according to the West-Haven criteria, who were submitted to neuropsychometric tests, electroencephalogram, brain Single Photon Emission Computed Tomography (SPECT), anthropometric measurements, handgrip strength (HGS) and dual energy X-ray absorptiometry exam (DXA). Multiple logistic regression analysis was performed to investigate the association between body composition measures and HE grade. Analysis of the area under the receiver operator characteristic (AUROC) curve revealed the values related to neurological manifestations (HE grades I and II). Reductions in APMT and HGS were associated with higher HE grades, suggesting a big impact caused by the loss of muscle mass and function on HE severity. The link between HE manifestations and anthropometric measures, namely APMT and HGS, point to a significant relation concerning skeletal muscles and the neurological impairment in this population.


Asunto(s)
Fuerza de la Mano/fisiología , Encefalopatía Hepática/fisiopatología , Fuerza Muscular/fisiología , Músculo Esquelético/fisiopatología , Anciano , Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Estudios Transversales , Electroencefalografía , Femenino , Encefalopatía Hepática/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/diagnóstico por imagen , Tomografía Computarizada de Emisión de Fotón Único
4.
J Chem Phys ; 138(11): 114504, 2013 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-23534646

RESUMEN

Expressions of some thermodynamic functions as correlation-function integrals, such as the Ornstein-Zernike integral, the Kirkwood-Buff integrals, and the integral formulas for virial coefficients, are recalled. It is noted, as has been remarked before, that the choice of molecular centers from which intermolecular distances are measured is arbitrary and that different choices lead to different forms of the correlation functions but that the integrals must be independent of those choices. This is illustrated with the second virial coefficients of hard spheres in one, two, and three dimensions, with that of gaseous propane in three dimensions, and with computer simulations of the pair correlations in water and in a dilute aqueous solution of propane.

6.
Diabetologia ; 55(8): 2256-66, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22610400

RESUMEN

AIMS/HYPOTHESIS: Hyperlipidaemia is an independent risk factor for the progression of diabetic nephropathy, but its molecular mechanism remains elusive. We investigated in mice how diabetes and hyperlipidaemia cause renal lesions separately and in combination, and the involvement of Toll-like receptor 4 (TLR4) in the process. METHODS: Diabetes was induced in wild-type (WT) and Tlr4 knockout (KO) mice by intraperitoneal injection of streptozotocin (STZ). At 2 weeks after STZ injection, normal diet was substituted with a high-fat diet (HFD). Functional and histological analyses were carried out 6 weeks later. RESULTS: Compared with treatment with STZ or HFD alone, treatment of WT mice with both STZ and HFD markedly aggravated nephropathy, as indicated by an increase in albuminuria, mesangial expansion, infiltration of macrophages and upregulation of pro-inflammatory and extracellular-matrix-associated gene expression in glomeruli. In Tlr4 KO mice, the addition of an HFD to STZ had almost no effects on the variables measured. Production of protein S100 calcium binding protein A8 (calgranulin A; S100A8), a potent ligand for TLR4, was observed in abundance in macrophages infiltrating STZ-HFD WT glomeruli and in glomeruli of diabetic nephropathy patients. High-glucose and fatty acid treatment synergistically upregulated S100a8 gene expression in macrophages from WT mice, but not from KO mice. As putative downstream targets of TLR4, phosphorylation of interferon regulatory factor 3 (IRF3) was enhanced in kidneys of WT mice co-treated with STZ and HFD. CONCLUSIONS/INTERPRETATION: Activation of S100A8/TLR4 signalling was elucidated in an animal model of diabetic glomerular injury accompanied with hyperlipidaemia, which may provide novel therapeutic targets in progressive diabetic nephropathy.


Asunto(s)
Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 1/patología , Diabetes Mellitus Tipo 2/patología , Nefropatías Diabéticas/patología , Hiperlipidemias/patología , Riñón/patología , Receptor Toll-Like 4/metabolismo , Animales , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 2/sangre , Nefropatías Diabéticas/sangre , Nefropatías Diabéticas/etiología , Progresión de la Enfermedad , Humanos , Hiperlipidemias/sangre , Hiperlipidemias/complicaciones , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal , Estreptozocina/farmacología
7.
Br J Cancer ; 105(6): 824-32, 2011 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-21829200

RESUMEN

BACKGROUND: Laminin-5 (Ln5), a heterotrimer composed of three chains (α3, ß3, and γ2), is a major component of the basement membrane in most adult tissues. One of the chains, Ln5-γ2, is a marker of invasive tumours because it is frequently expressed as a monomer in malignant tumours. Recent studies from our laboratories detected higher levels of Ln5-γ2 expression in basal cell carcinoma (BCC) than in trichoblastoma. Furthermore, Ln5-γ2 overexpression tended to correlate with aggressiveness in BCC. METHODS: In this study, we compared the expression of Ln5-γ2 in invasive squamous cell carcinoma (SCC, n = 62) of the skin to that in preinvasive Bowen's disease (BD, n = 51), followed by analysis of the role of Ln5-γ2 in cancer invasion in vitro. RESULTS: Immunohistochemically, the proportion of SCC cases (86%) strongly positive for Ln5-γ2 expression was higher than that of BD (16%). Real-time RT-PCR showed Ln5-γ2 overexpression in SCC cell line, A431, compared with normal keratinocyte cell line, HaCaT. Ln5-γ2 monomer and proteolytically cleaved, biologically active fragments of Ln5-γ2 were identified in SCC tumour extracts. In in vitro raft cultures, which simulate in vivo conditions, Ln5-γ2 siRNA significantly suppressed epidermal growth factor (EGF)-stimulated A431 cell invasion. CONCLUSION: Our results indicate that Ln5-γ2 has a role in cutaneous SCC invasion.


Asunto(s)
Carcinoma de Células Escamosas/metabolismo , Laminina/metabolismo , Neoplasias Cutáneas/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad de Bowen/metabolismo , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Femenino , Humanos , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Neoplasias Cutáneas/patología
8.
SAGE Open Med ; 9: 20503121211005992, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35154758

RESUMEN

OBJECTIVE: Long-term administration of dienogest, which is known to have effect on bone mineral density, is frequently done in patients with endometriosis and adenomyosis, but a few studies focused on the bone mineral density changes after finishing the long-term therapy. This study aimed to reveal the factors that adversely affect lumbar bone mineral density. METHOD: Fifty-seven premenopausal women who visited our hospital were diagnosed as either endometriosis or adenomyosis, and they were treated by dienogest for more than 115 weeks (26.5 months). Based on a previous report, bone mineral density changes less than 2% was categorized as the osteopenic group (n = 30), and the others were assigned to the unchanged group (n = 27). Bone mineral density was measured at the lumbar spine using dual-energy X-ray absorptiometry. A representative ovarian reserve marker, endogenous estradiol levels, and follicle-stimulating hormone levels were measured over time and were compared between the osteopenic and unchanged groups. RESULT: Duration of dienogest intake was 59.5 months (osteopenic group) versus 57.5 months (unchanged group). These patients experienced ovarian surgeries in a similar frequency, but the ovarian reserve in osteopenic group was impaired as suggested by the decline of endogenous estradiol level during intake of dienogest compared to that of unchanged group (p = 0.0146). Endogenous follicle-stimulating hormone level between osteopenic group and unchanged group did not reach statistically significant difference, although the osteopenic group showed relatively higher level. CONCLUSION: This study might suggest that decreased ovarian reserve as judged by endogenous estradiol level is a factor that negatively affect bone mineral density, and measurement of endogenous estradiol level during intake of dienogest could have a predictive meaning of future decreased bone mineral density level.

9.
Phys Rev Lett ; 104(3): 036101, 2010 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-20366660

RESUMEN

A class of density-functional models for wetting transitions is defined. A necessary condition for the transitions to be of higher than first order is derived. A locus of wetting transitions in the plane of two model field variables is determined on which there are states of first-order and of higher-order, including infinite-order, transitions. The observed behavior is rationalized via a different but related, analytically soluble model.

10.
Hum Reprod ; 24(12): 3042-8, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19684045

RESUMEN

BACKGROUND: The aim of this study was to evaluate the impact of post-operative oral contraceptives (OCs) use on the rate of recurrence after laparoscopic excision of ovarian endometrioma. METHODS: In May 2005, we introduced a 'post-operative OC recommendation' for patients treated with laparoscopic excision of endometrioma. That is, at the time of the operation, we provided each patient with information about OC, known and possible benefits and risks and let her decide whether to take OC. A retrospective cohort study included 87 patients who underwent a laparoscopy after May 2005. The endometrioma recurrence rate at 24 months was compared between those who used OC for the entire follow-up period OC (n = 34) and all of the others (n = 53). We also performed logistic regression analysis to identify variables associated with recurrence. A before-after study included another 224 patients who underwent a laparoscopy before May 2005 and compared the recurrence rate before and after introduction of the 'post-operative OC recommendation'. RESULTS: The recurrence rate in those who used OC for the entire period was significantly lower than in the 'others' group (2.9 versus 35.8%, relative risk 0.082, 95% CI 0.012-0.58, P < 0.001). Post-operative OC was determined as an independent variable associated with lower recurrence (OR 0.054, 95% CI 0.007-0.429, P < 0.001). The overall recurrence rate in patients who underwent laparoscopy after the introduction of the 'post-operative OC recommendation' was significantly lower than that in patients who received laparoscopy before the introduction (18.6 versus 33.1%, relative risk 0.56, 95% CI 0.32-0.97, P < 0.05). CONCLUSIONS: Post-operative OC use reduces the risk of ovarian endometrioma recurrence after laparoscopic excision. This information will help in appropriate planning of pre- and post-operative management.


Asunto(s)
Anticonceptivos Orales/uso terapéutico , Endometriosis/tratamiento farmacológico , Laparoscopía , Enfermedades del Ovario/tratamiento farmacológico , Ovariectomía , Adulto , Protocolos Clínicos , Terapia Combinada/estadística & datos numéricos , Endometriosis/prevención & control , Endometriosis/cirugía , Femenino , Humanos , Laparoscopía/estadística & datos numéricos , Enfermedades del Ovario/prevención & control , Enfermedades del Ovario/cirugía , Ovariectomía/estadística & datos numéricos , Cooperación del Paciente , Periodo Posoperatorio , Estudios Retrospectivos , Riesgo , Prevención Secundaria , Estadística como Asunto
11.
Exp Brain Res ; 193(4): 633-8, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19199099

RESUMEN

The coding of body part location may depend upon both visual and proprioceptive information, and allows targets to be localized with respect to the body. The present study investigates the interaction between visual and proprioceptive localization systems under conditions of multisensory conflict induced by optokinetic stimulation (OKS). Healthy subjects were asked to estimate the apparent motion speed of a visual target (LED) that could be located either in the extrapersonal space (visual encoding only, V), or at the same distance, but stuck on the subject's right index finger-tip (visual and proprioceptive encoding, V-P). Additionally, the multisensory condition was performed with the index finger kept in position both passively (V-P passive) and actively (V-P active). Results showed that the visual stimulus was always perceived to move, irrespective of its out- or on-the-body location. Moreover, this apparent motion speed varied consistently with the speed of the moving OKS background in all conditions. Surprisingly, no differences were found between V-P active and V-P passive conditions in the speed of apparent motion. The persistence of the visual illusion during the active posture maintenance reveals a novel condition in which vision totally dominates over proprioceptive information, suggesting that the hand-held visual stimulus was perceived as a purely visual, external object despite its contact with the hand.


Asunto(s)
Ilusiones , Percepción de Movimiento , Propiocepción , Análisis de Varianza , Femenino , Dedos , Humanos , Masculino , Estimulación Luminosa , Adulto Joven
12.
J Phys Chem B ; 122(13): 3655-3665, 2018 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-29357255

RESUMEN

Temperature-, pressure-, and salt-concentration-induced variations in the solubility of small nonpolar solutes in aqueous solution and the corresponding variations in the solvent-induced pair attraction between such solute molecules are investigated. The variations in the solvation free energy of a solute and those in the solvent-induced pair attraction are well reproduced by a mean-field approximation in which the repulsive cores of solute molecules are treated as hard spheres and the mean-field energy of a solute molecule is taken to be the average potential energy that the solute molecule feels in solution. The mechanisms of variation in the solvation free energy and those of variation in the solvent-induced pair potential, with increasing temperature, pressure, and salt concentration, are clarified. Correlations between the solvation free energy and the solvent-induced pair potential at a contact distance in temperature, pressure, and salt concentration variations are near linear in any mode of variation, but the slope of the linear relation is dependent on the mode of variation and is determined by a ratio of the solvation thermodynamic quantities characteristic of each mode of variation.

13.
Cancer Res ; 55(12): 2615-9, 1995 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-7780977

RESUMEN

Effects of 1,15-bis(ethylamino)-4,8,12-triazapentadecane (BE3333), the least toxic bis(ethyl)pentaamine, on the growth of tumor cells were studied in in vitro systems and with tumor xenografts in mice. BE3333 suppressed ornithine decarboxylase and S-adenosylmethionine decarboxylase, induced spermidine/spermine N1-acetyltransferase, and thus decreased the amount of polyamines. BE3333 accumulated in cells at a concentration 3-5-fold that of spermine in control cells through the polyamine transport system. The accumulated BE3333 inhibited protein synthesis, especially mitochondrial protein synthesis, and decreased the amount of ATP. The inhibition of protein synthesis was correlated with the subsequent inhibition of cell growth. BE3333 showed inhibitory effects in in vitro systems against the growth of mouse FM3A mammary carcinoma cells, human SW480 and SW620 colon tumor cells, Lu-65A and A549 lung tumor cells, MCF-7 breast tumor cells, and MALME-3M and A375 melanoma cells at a range of 0.5-10 microM. Intravenous (30 mg/kg) or i.p. (50 mg/kg) daily injections of BE3333 for 5 or 7 days greatly suppressed the growth of human colon tumor SW620 xenotransplanted into nude mice. Similar antitumor activity was obtained with continuous infusion of BE3333 into the peritoneal cavity (80 mg/kg), but not with p.o. administration (200 mg/kg). BE3333 also showed inhibitory effects against the growth of lung tumors (Lu-65, Lx-1, Lc-1, and Lu-61), stomach tumors (Sc-6 and St-15), and melanoma (SEKI) xenotransplanted into nude mice. The results indicate that BE3333 is effective against both rapid- and slow-growing tumors, with reasonable short-term host toxicity.


Asunto(s)
Antineoplásicos/farmacología , División Celular/efectos de los fármacos , Neoplasias del Colon/tratamiento farmacológico , Inhibidores de Crecimiento/farmacología , Poliaminas/metabolismo , Acetiltransferasas/metabolismo , Adenosilmetionina Descarboxilasa/antagonistas & inhibidores , Animales , Neoplasias de la Mama , Línea Celular , Humanos , Cinética , Neoplasias Pulmonares , Neoplasias Mamarias Experimentales , Ratones , Ratones Desnudos , Inhibidores de la Ornitina Descarboxilasa , Poliaminas/uso terapéutico , Putrescina/metabolismo , Espermidina/metabolismo , Espermina/metabolismo , Factores de Tiempo , Trasplante Heterólogo , Células Tumorales Cultivadas
14.
Cancer Res ; 61(16): 6248-54, 2001 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-11507079

RESUMEN

In highly vascular malignant glioma, glioma cells themselves may express angiogenic factors and induce angiogenesis. Recent studies have shown that novel angiogenic factors, angiopoietin-1 (Ang1) and -2 (Ang2), play important roles in the modulation of vasculogenesis and angiogenesis. In this study, we determined Ang2 mRNA expression in cultured human malignant glioma cells (U105, U251, and U373 MG) by reverse transcriptase-PCR. Western blot analysis and immunocytochemical analysis with antihuman Ang2 antibody revealed that Ang2 protein was expressed and secreted by these cells. Furthermore, hypoxia increased the Ang2 protein level in cultured glioma cells. Serial sections of 32 human glioma tissues (14 glioblastomas, eight anaplastic astrocytomas, seven astrocytomas, and three pilocytic astrocytomas) were immunostained against Ang2, vascular endothelial growth factor, Tie2, von Willebrand factor, and alpha smooth muscle actin. The immunoreactivity of each angiogenic factor was higher in malignant gliomas than in low-grade gliomas. Ang2 protein was detected not only in endothelial cells but also in glioma cells, and its expression was prominent in both the area surrounding the necrosis and the periphery of glioblastomas. In the area surrounding necrosis, Ang2 was highly expressed and tumor vessels showed regression. In the tumor periphery, Ang2 was highly expressed and many small vessels stained positively for von Willebrand factor but not for alpha smooth muscle actin, suggesting angiogenesis. Statistical analysis revealed that the Ang2 expression was negatively correlated with vessel maturation in malignant gliomas and that vascular endothelial growth factor expression was positively correlated with vessel maturation in low-grade gliomas (P < 0.05). These results suggest that glioma cells themselves express Ang2 and that expression may be induced by hypoxic stimulation and may play a crucial role in the vessel maturation, angiogenesis, and vessel regression in malignant glioma.


Asunto(s)
Neoplasias Encefálicas/irrigación sanguínea , Neoplasias Encefálicas/metabolismo , Glioma/irrigación sanguínea , Glioma/metabolismo , Neovascularización Patológica/fisiopatología , Proteínas/fisiología , Adolescente , Adulto , Anciano , Secuencia de Aminoácidos , Angiopoyetina 2 , Neoplasias Encefálicas/patología , Hipoxia de la Célula/fisiología , Niño , Femenino , Glioma/patología , Humanos , Inmunohistoquímica , Recién Nacido , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Neovascularización Patológica/metabolismo , Biosíntesis de Proteínas , Proteínas/genética , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
15.
J Phys Condens Matter ; 28(24): 244016, 2016 06 22.
Artículo en Inglés | MEDLINE | ID: mdl-27116351

RESUMEN

We treat two different density-functional models of the structures and tensions of the interfaces between phases on approach to the tricritical point of three-phase equilibrium. The major objective is to account for some of the results of earlier experimental measurements of these tensions. The thermodynamic background is first reviewed, including representations of the properties near the critical endpoints and tricritical point and of the wetting transitions that may occur on approach to those critical points. The first of the models treated is analytically soluble. Its properties are illuminating but at the price of some artificiality paid for its analytical solubility. The second model, called model T, is in a class of those treated in the past and analyzed numerically. Some of its properties are obtained with sufficient precision to allow one to conclude with near certainty what the analytically exact results would be. This model, too, illuminates the experimental measurements. It is noted where its properties are in accord with those of the analytically soluble model and where the two differ.

16.
J Phys Chem B ; 120(47): 12127-12134, 2016 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-27933937

RESUMEN

A simple model of a hydrophobic polymer in water is studied. The model polymer, a chain of Lennard-Jones particles with a fixed bond length, is designed in such a way that it undergoes a coil-to-globule conformational change near room temperature upon heating in liquid water. At low temperatures (≲270 K), the polymer chain under vacuum takes a globular conformation, whereas in water, it adopts an extended form. At higher temperatures (≳320 K), the polymer has a more compact conformation in water than under vacuum. The same polymer chain in a nonpolar solvent is always extended and shows no sign of a coil-to-globule transformation up to 360 K. The heat-induced collapse of the polymer uniquely observed in water is not attributed to the hydrophobic effect on individual monomers, but it is correlated with the temperature dependence of the potential of mean force between two monomers at contact distance.


Asunto(s)
Metano/química , Polímeros/química , Agua/química , Interacciones Hidrofóbicas e Hidrofílicas , Cinética , Modelos Moleculares , Conformación Molecular , Transición de Fase , Temperatura , Termodinámica , Vacio
17.
J Neurosci ; 20(23): 8750-3, 2000 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-11102482

RESUMEN

Acoustic overstimulation is one of the major causes of hearing loss. Glutamate is the most likely candidate neurotransmitter for afferent synapses in the peripheral auditory system, so it was proposed that glutamate excitotoxicity may be involved in noise trauma. However, there has been no direct evidence that noise trauma is caused by excessive release of glutamate from the inner hair cells (IHCs) during sound exposure because studies have been hampered by powerful glutamate uptake systems in the cochlea. GLAST is a glutamate transporter highly expressed in the cochlea. Here we show that after acoustic overstimulation, GLAST-deficient mice show increased accumulation of glutamate in perilymphs, resulting in exacerbation of hearing loss. These results suggest that GLAST plays an important role in keeping the concentration of glutamate in the perilymph at a nontoxic level during acoustic overstimulation. These findings also provide further support for the hypothesis that IHCs use glutamate as a neurotransmitter.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/genética , Ácido Glutámico/metabolismo , Pérdida Auditiva Provocada por Ruido/genética , Sistema de Transporte de Aminoácidos X-AG , Animales , Umbral Auditivo , Transporte Biológico/genética , Cóclea/metabolismo , Cóclea/patología , Cóclea/fisiopatología , Potenciales Evocados Auditivos del Tronco Encefálico/genética , Pérdida Auditiva Provocada por Ruido/fisiopatología , Ratones , Ratones Noqueados , Ruido/efectos adversos , Perilinfa/metabolismo
18.
Biochim Biophys Acta ; 1219(2): 555-8, 1994 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-7918658

RESUMEN

A cDNA encoding for a heat shock protein 30 (HSP30) of Aspergillus nidulans and the promoter region of its gene were analyzed for their primary structures. The promoter region had no heat shock element but possessed three inverted repeat sequences. Northern blot hybridization indicated that the expression of the HSP30 gene was high at a normal temperature and was slightly accelerated at elevated temperatures in A. nidulans cells. Although the deduced amino acid sequence of the A. nidulans HSP30 had a domain highly conserved among other small HSPs from different species, it showed a sequence homology of only 42% even in comparison with the most closely related molecular species, Neurospora crassa HSP30. These findings suggest that the present HSP30 belongs to a novel subfamily of low-molecular-weight HSPs.


Asunto(s)
Aspergillus nidulans/genética , Proteínas de Choque Térmico/genética , Regiones Promotoras Genéticas , Secuencia de Aminoácidos , Secuencia de Bases , ADN Complementario/genética , Expresión Génica , Genes Fúngicos , Datos de Secuencia Molecular , ARN de Hongos/genética , ARN Mensajero/genética , Alineación de Secuencia , Homología de Secuencia de Aminoácido
19.
Biochim Biophys Acta ; 445(2): 294-308, 1976 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-182278

RESUMEN

In order to elucidate the molecular structure of glucose oxidase (beta-D-glucose: oxygen 1-oxidoreductase, EC 1.1.3.4) and the roles of its carbohydrate moiety, chemical, physiochemical and immunological experiments were performed with enzyme samples before and after periodate oxidation. Hydrodynamic parameters indicated that the native enzyme was a globular protein with values of 1.21 for the frictional ratio and 43 A for the Stokes radius. The enzyme contained about 12% carbohydrate by weight, of which the main component was mannose. The periodate treatment decreased the carbohydrate content to about 40% of its original value. Slight modifications were detected in the absorbance spectrum and the content of arginyl residue. However, no significant alteration was brought about by this treatment in the catalytic parameters, immunological reactivities of the gross structure, not in the secondary and quaternary structures of the protein moity. Thermal denaturation temperature (about 72.5 degrees C) and the enthalpy of denaturation (about 450 kcal/mol) were common to the native and the periodate-oxodozed enzymes. The native was found to be quite resistant to sodium dodecyl sulfate and fairly stable to urea and heating. The periodate-oxidized enzyme was also stable to heat treatment, but it showed a diminished stability when denaturing agents were present. Kinetic analyses of the thermal inactivation processes showed that the entropy of activation was greatly decreased by the denaturing agents, especially in the case of the periodate-oxidized enzyme. It is concluded that the carbohydrate moiety of the enzyme plays a role in increasing the stability of the protein moiety, but does not directly participate in the catalytic activity, the immunological reactivity, or in maintaining the conformation of the enzyme protein.


Asunto(s)
Glucosa Oxidasa , Aminoácidos/análisis , Aspergillus niger/enzimología , Calorimetría , Glucosa Oxidasa/metabolismo , Hexosaminas/análisis , Hexosas/análisis , Inmunodifusión , Peso Molecular , Oxidación-Reducción , Ácido Peryódico , Pruebas de Precipitina , Unión Proteica , Termodinámica , Urea
20.
Biochim Biophys Acta ; 992(3): 400-3, 1989 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-2476186

RESUMEN

Western blot analyses of yolk proteins of the White Leghorn hens showed that an ovalbumin-like molecule was included in day 16 eggs but not in the ovarian follicles, and very little in newly deposited eggs. Northern hybridization, as well as in vitro translation, of poly(A)+ RNAs prepared from the yolk sac membranes of developing embryos gave no signal for ovalbumin messages. These results imply that the present ovalbumin-like protein of yolk has its origin in egg white, not being a de novo synthesis product in the yolk sac membranes.


Asunto(s)
Ovalbúmina/biosíntesis , Saco Vitelino/fisiología , Animales , Western Blotting , Embrión de Pollo , Electroforesis en Gel Bidimensional , Peso Molecular , Ovalbúmina/genética , Ovalbúmina/aislamiento & purificación , Poli A/genética , Biosíntesis de Proteínas , ARN/genética , ARN Mensajero
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