Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 63
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
2.
Int J Sports Med ; 36(7): 519-25, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25760149

RESUMEN

One distinctive trait of kendo, the Japanese martial art of fencing, is the execution of sustained, high-effort vocalizations during actions. The purpose of this study was to determine the effect of these vocalizations on respiratory functions. First, the intensity of 3 kendo exercises was quantified by measuring oxygen uptake (V̇O2) and comparing it with V̇O2max measured during treadmill tests of 8 university kendo athletes. Respiratory variables of these 8 athletes were then analyzed using a portable breath gas analyzer during the most intensive kendo exercise, kakari-keiko, with and without vocalization. Breathing frequency (fB) increased regardless of vocalization, but in trials with vocalization, fB and ventilation were significantly lower, and expiration time was significantly longer. Components of expired gases were also affected by vocalization. Although there was no significant difference in oxygen uptake, vocalization yielded a reduction in carbon dioxide output (V̇CO2) and an increase in fraction of end-tidal carbon dioxide (FetCO2). We thus conclude that these vocalizations greatly affect expiration breathing patterns in kendo. Moreover, repetition of kakari-keiko caused a reduction in V̇CO2 and an increase in FetCO2 and CO2 storage. We consider the possibility that the sustained high-effort vocalizations of kendo also increase cerebral blood flow.


Asunto(s)
Dióxido de Carbono/metabolismo , Ejercicio Físico/fisiología , Artes Marciales/fisiología , Voz/fisiología , Adolescente , Pruebas Respiratorias/métodos , Prueba de Esfuerzo , Humanos , Masculino , Oxígeno/metabolismo , Respiración , Adulto Joven
3.
Oncogene ; 34(33): 4403-11, 2015 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-25417706

RESUMEN

The E2 ubiquitin conjugating enzyme Ubc13 and the E3 ubiquitin ligases Rad18 and Rnf8 promote homologous recombination (HR)-mediated double-strand break (DSB) repair by enhancing polymerization of the Rad51 recombinase at γ-ray-induced DSB sites. To analyze functional interactions between the three enzymes, we created RAD18(-/-), RNF8(-/-), RAD18(-/-)/RNF8(-/-) and UBC13(-/-)clones in chicken DT40 cells. To assess the capability of HR, we measured the cellular sensitivity to camptothecin (topoisomerase I poison) and olaparib (poly(ADP ribose)polymerase inhibitor) because these chemotherapeutic agents induce DSBs during DNA replication, which are repaired exclusively by HR. RAD18(-/-), RNF8(-/-) and RAD18(-/-)/RNF8(-/-) clones showed very similar levels of hypersensitivity, indicating that Rad18 and Rnf8 operate in the same pathway in the promotion of HR. Although these three mutants show less prominent defects in the formation of Rad51 foci than UBC13(-/-)cells, they are more sensitive to camptothecin and olaparib than UBC13(-/-)cells. Thus, Rad18 and Rnf8 promote HR-dependent repair in a manner distinct from Ubc13. Remarkably, deletion of Ku70, a protein essential for nonhomologous end joining (NHEJ) significantly restored tolerance of RAD18(-/-) and RNF8(-/-) cells to camptothecin and olaparib without affecting Rad51 focus formation. Thus, in cellular tolerance to the chemotherapeutic agents, the two enzymes collaboratively promote DSB repair by HR by suppressing the toxic effect of NHEJ on HR rather than enhancing Rad51 focus formation. In contrast, following exposure to γ-rays, RAD18(-/-), RNF8(-/-), RAD18(-/-)/RNF8(-/-) and UBC13(-/-)cells showed close correlation between cellular survival and Rad51 focus formation at DSB sites. In summary, the current study reveals that Rad18 and Rnf8 facilitate HR by two distinct mechanisms: suppression of the toxic effect of NHEJ on HR during DNA replication and the promotion of Rad51 focus formation at radiotherapy-induced DSB sites.


Asunto(s)
Reparación del ADN por Unión de Extremidades/genética , Proteínas de Unión al ADN/genética , Recombinación Homóloga/genética , Recombinasa Rad51/genética , Antígenos Nucleares/genética , Línea Celular Tumoral , Reparación del ADN/genética , Replicación del ADN/genética , Células HCT116 , Humanos , Autoantígeno Ku , Enzimas Ubiquitina-Conjugadoras/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación/genética
4.
J Sports Med Phys Fitness ; 55(7-8): 797-804, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25369277

RESUMEN

AIM: This randomized controlled study was designed to examine the effects of reduced coenzyme Q10 (ubiquinol; CoQ10) supplementation on blood pressure (BP) and exercise-induced muscle damage in kendo athletes during a 4-day kendo training camp. METHODS: In a double-blinded manner, 32 young kendo athletes were randomly assigned to supplement with either placebo or CoQ10 (600 mg) daily for 11 days from 1 week prior to camp to end of camp. BP was measured every morning after waking up during the training camp. Blood samples were taken at 3 time points; 1 week and 1 day prior and upon completion of training camp at 17:30. Statistical analysis was performed by repeated-measures analysis of variance followed by Bonferroni/Dunn post-hoc tests. RESULTS: Before the training camp started, there were no differences in diastolic BP between these groups. However, after kendo training started, diastolic BP in the CoQ10 group was significantly lower than that in the placebo group (P<0.05). Plasma creatine kinase (CK) and myoglobin (Mb) concentrations were significantly increased in both groups during the camp (P<0.05), whereas there were no significant differences in CK and Mb between CoQ10 and placebo groups (CK: P=0.82, Mb: P=0.69). CONCLUSION: Oral supplementation with reduced form of CoQ10 (ubiquinol; Kaneka QHTM) showed a significant hypotensive effect in young male kendo athletes during a 4-day kendo training camp, although it did not significantly ameliorate kendo exercise-induced muscle damage.


Asunto(s)
Presión Sanguínea/efectos de los fármacos , Artes Marciales/fisiología , Músculo Esquelético/efectos de los fármacos , Ubiquinona/análogos & derivados , Biomarcadores/sangre , Creatina Quinasa/sangre , Suplementos Dietéticos , Método Doble Ciego , Humanos , Masculino , Mioglobina/sangre , Educación y Entrenamiento Físico , Ubiquinona/administración & dosificación , Adulto Joven
5.
Clin Exp Obstet Gynecol ; 41(1): 10-6, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24707674

RESUMEN

OBJECTIVE: The authors evaluated the effectiveness and safety of "neo-metoro" or 'mini-metoro" metreurynters plus oxytocin for labor induction and assessed differences in parturition outcomes, according to the metreurynter used at induction initiation. MATERIALS AND METHODS: The authors retrospectively reviewed 146 consecutive women with live singleton pregnancies, and who underwent induction. Parturition outcomes were vaginal delivery achieved within the planned schedule (VDPS), vaginal delivery finally achieved (VDF), and induction-to-delivery interval (IDI). Women were divided into neo-metoro, mini-metoro, and without metreurynter groups based on metreurynter use at induction initiation. The authors examined the relationships of metreurynter groups with factors, parturition outcomes, and adverse events. In 113 women who underwent two-day induction, the authors calculated IDI and adjusted odds ratio (AOR) for achieving delivery per unit time. RESULTS: VDPS rates were 65% in nulliparous and 81% in multiparous women. VDF rates were 78% in nulliparous and 96% in multiparous women. AORs for VDPS were 0.30 in nulliparous women and 0.18 in Bishop score (BS) 1-3 class. AORs for VDF were 0.04 in BS1-3 class and 0.14 in BS4-5 class. In 113 women undergoing two-day induction, AORs for achieving delivery per unit time were 0.45 in nulliparous women, 0.46 in obese women, and 0.48 in BS1-3 class. Neo-metoro use at induction initiation tended to reduce IDI. CONCLUSIONS: Labor induction using these metreurynters plus oxytocin is safe and effective. The advantages of neo-metoro over mini-metoro use at induction initiation remain unclear; neo-metoro use at induction initiation may reduce IDI.


Asunto(s)
Catéteres , Trabajo de Parto Inducido/métodos , Oxitócicos/administración & dosificación , Oxitocina/administración & dosificación , Administración Intravaginal , Adulto , Terapia Combinada , Diseño de Equipo , Femenino , Rotura Prematura de Membranas Fetales/terapia , Humanos , Japón , Paridad , Embarazo , Resultado del Embarazo , Modelos de Riesgos Proporcionales , Estudios Retrospectivos
6.
Br J Cancer ; 94(12): 1874-8, 2006 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-16721362

RESUMEN

To evaluate the c-kit expression in breast cancer, 217 invasive ductal carcinomas of the breast were immunohistochemically stained for c-kit protein. The c-kit expression was positive in 59 (27%) of 217 tumours, while the c-kit expression was negative in 158 (73%) of 217 tumours. There was a significant correlation between a negative expression of the c-kit protein and lymph node metastasis (P < 0.0001), and the incidence of a negative expression of the c-kit protein increased as the number of the metastatic lymph nodes increased (P = 0.0003). The c-kit expression did not significantly correlate with the tumour size, nuclear grade, oestrogen receptor status, MIB-1 counts and p53 protein expression. A univariate analysis indicated the patients with the negative c-kit expression to have a worse disease-free survival (DFS) than those with the positive c-kit expression (P = 0.0041), while a multivariate analysis determined lymph node metastases and the MIB-1 counts to be independently significant factors for DFS. In conclusion, a loss of the c-kit expression was found in about three-fourth of invasive ductal carcinoma of the breast and was associated with lymph node metastases. The prognostic implications of the c-kit expression seem to be due to fact that a loss of the c-kit expression is associated with an advanced stage of breast cancer.


Asunto(s)
Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Carcinoma Ductal de Mama/metabolismo , Carcinoma Ductal de Mama/patología , Proteínas Proto-Oncogénicas c-kit/metabolismo , Biomarcadores de Tumor/análisis , Neoplasias de la Mama/mortalidad , Carcinoma Ductal de Mama/mortalidad , Supervivencia sin Enfermedad , Femenino , Humanos , Metástasis Linfática/patología , Estadificación de Neoplasias , Pronóstico , Análisis de Supervivencia , Tasa de Supervivencia
7.
Br J Oral Maxillofac Surg ; 42(5): 405-9, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15336765

RESUMEN

We investigated the redox state of albumin in the synovial fluid from patients with temporomandibular joint (TMJ) disorders (TMD) to evaluate the relation between the cause of the TMD and the number of types of oxygen in synovial fluid. The albumin was fractionated into three components, human mercaptalbumin (HMA, reduced form) and two types human non-mercaptalbumin (HNA, oxidized form), by high-performance liquid chromatography (HPLC). The 63 patients were divided into three groups radiologically, and the ratios of the redox state of the synovial fluid in each group were compared. The fraction of HNA was significantly higher in patients with advanced disease than in patients with early disease. This indicates that the TMJ is affected by intra-articlular oxidative stress, and the severity of TMD correlates closely with the number of oxidative factors. Oxidative stress was thought to be responsible for the genesis of TMD.


Asunto(s)
Albúminas/análisis , Líquido Sinovial/metabolismo , Trastornos de la Articulación Temporomandibular/metabolismo , Adolescente , Adulto , Anciano , Cromatografía Liquida , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Radiografía , Especies Reactivas de Oxígeno/análisis , Albúmina Sérica/análisis , Trastornos de la Articulación Temporomandibular/diagnóstico por imagen , Trastornos de la Articulación Temporomandibular/etiología
8.
NMR Biomed ; 14(6): 367-75, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11599035

RESUMEN

We have studied saturation transfer in hydrophilic, cross-linked copolymer gels from irradiated polymer protons to observed water protons, using f2 (ppm) profiles of [1 - (I(infinity)/I(0))], [(I(0)/I(infinity)) - 1] or 1/T(IS)(H2O), where I(0) and I(infinity) are the longitudinal magnetization of the observed water protons before and after long-time-f2-irradiation on polymer protons, respectively, and 1/T(IS)(H2O) is the cross-relaxation rate. (A) [1 - (I(infinity)/I(0))] (magnetization transfer ratio, MTR) was used in magnetic resonance imaging (MRI) as the MTR imaging. 1/T(IS)(H2O) (cross-relaxation rate) was used in the imaging of the magnetization transfer rate constant. This method was quite time-consuming compared with MTR imaging. However, f2 (ppm) profiles of [(I(0)/I(infinity)) - 1] correlated well with corresponding profiles of 1/T(IS)(H2O), because [(I(0)/I(infinity)) - 1] is equal to 1/[T(IS)(H2O)/T1(H2O)]. These results lead us to the conclusion that [(I(0)/I(infinity)) - 1] might be applicable to cross-relaxation rate (CR)-like imaging, i.e. equivalent CRI. (B) W (%) (dry weight) profiles of [(I(0)/I(infinity)) - 1] and 1/T(IS)(H2O), obtained by near-resonance f2-irradiation, seem to indicate participation of molecular rigidity and an amount of bound water. However, those values, monitored with off-resonance f2-irradiation, seem to be independent of monomer composition and to indicate mainly participation of rigidity, i.e. W (%) of copolymer gels.


Asunto(s)
Espectroscopía de Resonancia Magnética/instrumentación , Fantasmas de Imagen , Reactivos de Enlaces Cruzados , Geles , Magnetismo , Polímeros , Protones , Factores de Tiempo , Agua
9.
Jpn J Physiol ; 51(2): 159-68, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11405908

RESUMEN

Fourier transform analysis was applied to elucidate the periodical and self-similar properties in the DNA sequences mainly of beta-globin genes in different species, and the evolutionary change in those properties was then investigated. Map patterns of a two-dimensional DNA walk showed that the stretches of exons are significantly shorter than those of introns, suggesting that the evolution of exons is driven by natural selection, whereas that of introns is generated by unknown internal rules. Using a monomer analysis, we obtained the power spectra of four different bases, A, G, C, and T, in DNA sequences. Periodicities in the short- (2 to 10 base pairs [bp]), medium- (10 to 50 bp) and long-range order (50 to 300 bp) of beta-globin gene sequences could be observed, and power spectral densities of these periodicities were increased with evolution. These results suggest the existence of the internal rules in the occurrence of the synonymous and nonsynonymous substitutions in the sequences, the destabilization of the interaction between DNA and histone protein, and the stabilization of the chromatin structure, respectively. Moreover, 1/f(alpha) analysis of the power spectra (log-log plot) in the far long-range region (160 to 16,000 bp) suggested the increase in the self-similarity (the fractal structure) of DNA sequences with evolution. A general trend of the increase in a 3 bp periodicity with evolution might be functionally related to the CAG trinucleotide repeat diseases such as Huntington chorea, where a marked periodicity of 3 bp could be observed. Fourier transform analysis applied to a DNA sequence offers a great new avenue for extracting information on the evolution of a DNA sequence.


Asunto(s)
Evolución Molecular , Análisis de Fourier , Globinas/genética , Periodicidad , Homología de Secuencia , Animales , Secuencia de Bases , Exones , Humanos , Intrones , Datos de Secuencia Molecular , Análisis de Secuencia de ADN , Repeticiones de Trinucleótidos
10.
Biochim Biophys Acta ; 1511(1): 42-8, 2001 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-11248203

RESUMEN

We have applied the transition state theory of Eyring et al. (The Theory of Rate Processes, McGraw-Hill, 1941) to water transport across cell membranes. We have then evaluated free energy (Delta F(not equal)), enthalpy (Delta H(not equal)) and entropy (Delta S(not equal)) of activation for water permeation across membranes, such as Arbacia eggs, Xenopus oocytes with or without aquaporin water channels, mammalian erythrocytes, aquaporin proteoliposomes, liposomes and collodion membrane. Delta H(not equal) was found to be correlated with Delta S(not equal). This is so-called Delta H(not equal) and Delta S(not equal) compensation over the ranges of Delta H(not equal) and Delta S(not equal) from 2 to 22 kcal/mol and from -26 to 45 e.u., respectively, indicating that low Delta H(not equal) values correspond to negative Delta S(not equal). Large positive Delta S(not equal) and high Delta H(not equal) values might be accompanied by reversible breakage of secondary bonds in the membrane, presumably in membrane lipid bilayer. Largely negative Delta S(not equal) and low Delta H(not equal) values for aquaporin water channels, aquaporin proteoliposomes and porous collodion membrane could be explained by the immobilization of permeating water molecules in the membrane, i.e., the partial loss of rotational and/or translational freedoms of water molecules in water channels.


Asunto(s)
Membrana Celular/metabolismo , Agua/metabolismo , Animales , Permeabilidad de la Membrana Celular , Colodión , Modelos Teóricos , Presión Osmótica , Erizos de Mar , Termodinámica
11.
Tokai J Exp Clin Med ; 26(3): 93-9, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11885755

RESUMEN

PURPOSE: To investigate the oxidative status of albumin in the aqueous humor and serum of senile cataract patients with diabetes in order to clarify the pathogenesis of this condition. METHODS: High-performance liquid chromatography (HPLC) was employed to measure the reduced form of albumin (mercaptalbumin) and the oxidized form of albumin (nonmercaptalbumin) in serum and aqueous humor. The mercaptalbumin, nonmercaptalbumin-1, and nonmercaptalbumin-2 fractions in aqueous humor obtained at the start of cataract surgery and in serum obtained intraoperatively were analyzed by HPLC in 7 senile cataract patients with diabetic retinopathy (2 men and 5 women aged 70+/-9.8 years). RESULTS: The mean content (%) of mercaptalbumin, nonmercaptalbumin-1, and nonmercaptalbumin-2 in serum albumin from the diabetic patients was 60.3+/-7.8, 36.9+/-6.6, and 2.7+/-1.7%, respectively, while the corresponding values for aqueous humor albumin were 40.0+/-14.1, 52.4+/-12.6, and 7.5+/-3.6%. When the mercaptalbumin content (%) of aqueous humor albumin was compared between patients with active and inactive diabetic retinopathy, the respective values were 47.0+/-9.1% and 22.8+/-5.7%. A significant correlation mercaptalbumin content (%) of aqueous humor albumin did not show with the HbA1c level, but there was still a relationship (Y = 5.0 x - 2.7, r = 0.80, and p < 0.052). CONCLUSION: The increase of mercaptalbumin (the reduced form of albumin) in the aqueous humor of patients with diabetic retinopathy probably resulted from an increase of retinal vascular permeability.


Asunto(s)
Humor Acuoso/metabolismo , Catarata/complicaciones , Catarata/metabolismo , Retinopatía Diabética/complicaciones , Albúmina Sérica/metabolismo , Anciano , Anciano de 80 o más Años , Envejecimiento/fisiología , Catarata/etiología , Cromatografía Líquida de Alta Presión , Femenino , Hemoglobina Glucada/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Isoformas de Proteínas/metabolismo , Albúmina Sérica Humana
12.
Magn Reson Imaging ; 18(4): 379-85, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10788714

RESUMEN

A prospective study was performed to investigate the correlations between saturation transfer ratio (STR) and histologic parameters of invasive ductal carcinomas in human breast. The histologic parameters investigated were the extent of fibrosis in the intercellular matrix, dysplastic changes of nuclei, and mitotic index. Twenty-seven patients with breast carcinoma were examined using an off-resonance saturation pulse in conjunction with conventional field-echo T(1)-weighted imaging at frequency offsets of 448 Hz and 1200 Hz from water resonance. The values of STR at frequency offset of 1200 Hz (STR(1200)) increased from non-scirrhous carcinoma to scirrhous carcinoma. Although STR(1200) showed correlation with the extent of fibrosis in the intercellular matrix (p<0.01, n = 27), they did not correlate with the dysplastic changes of nuclei or mitotic index. On the other hand, the values of STR at frequency offset of 448 Hz (STR(448)) demonstrated close correlation to dysplastic changes of nuclei and mitotic index (p<0.01, n = 27). STR(1200) correlates with the structural characteristics and STR(448) correlates with the nature of malignant cells with regard to nuclear dysplasia and mitotic potential.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico , Imagen por Resonancia Magnética , Adenocarcinoma Escirroso/diagnóstico , Adenocarcinoma Escirroso/patología , Adulto , Anciano , Mama/patología , Neoplasias de la Mama/patología , Carcinoma Ductal de Mama/patología , Femenino , Humanos , Persona de Mediana Edad , Estudios Prospectivos
13.
Biochim Biophys Acta ; 1474(1): 23-30, 2000 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-10699486

RESUMEN

In order to provide new insight into the molecular mechanism of perforating trauma-induced cataract formation in an 8-week-old ddY mouse lens, we performed an in situ investigation into changes in the water-protein and/or protein-protein interactions by using 500 MHz (1)H-NMR spectroscopy, and into structural alterations in lens proteins by using Raman spectroscopy. Cross-relaxation times of water protons in the perforated opaque lens were considerably shorter than those in the intact transparent lens, whereas there was no significant difference in water content, suggesting a drastic change in water-protein and protein-protein interactions in the perforated lens. In addition, there was no significant difference in the intensity ratios of several key Raman bands between intact and perforated lenses, indicating that no significant local and overall conformational changes in lens protein itself occur in the perforated lens. The present (1)H-NMR and Raman results lead us to the conclusion that changes leading to lens opacification in the perforating trauma-induced cataract appear to involve the rapid formation of immobile large lens protein aggregates without formation of intra- and intermolecular disulfide linkages, and rapid increase in a fraction of bound water associated with large protein aggregates.


Asunto(s)
Catarata/metabolismo , Cristalinas/metabolismo , Cristalino/metabolismo , Animales , Catarata/etiología , Cristalinas/química , Espectroscopía de Resonancia Magnética , Ratones , Espectrometría Raman , Heridas y Lesiones
14.
Protein Sci ; 8(11): 2541-5, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10595563

RESUMEN

Using heteronuclear NMR spectroscopy, we studied the solution structure and dynamics of bovine beta-lactoglobulin A at pH 2.0 and 45 degrees C, where the protein exists as a monomeric native state. The monomeric NMR structure, comprising an eight-stranded continuous antiparallel beta-barrel and one major alpha-helix, is similar to the X-ray dimeric structure obtained at pH 6.2, including betaI-strand that forms the dimer interface and loop EF that serves as a lid of the interior hydrophobic hole. [1H]-15N NOE revealed that betaF, betaG, and betaH strands buried under the major alpha-helix are rigid on a pico- to nanosecond time scale and also emphasized rapid fluctuations of loops and the N- and C-terminal regions.


Asunto(s)
Lactoglobulinas/química , Secuencia de Aminoácidos , Animales , Bovinos , Variación Genética , Concentración de Iones de Hidrógeno , Lactoglobulinas/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Resonancia Magnética Nuclear Biomolecular , Estructura Secundaria de Proteína , Soluciones
15.
Neurol Res ; 21(3): 250-4, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10319332

RESUMEN

The clinical applicability of magnetization transfer (MT) technique in magnetic resonance imaging (MRI) for the estimation of the histological and constitutional feature of brain tumors was investigated. MT effect was evaluated by measuring the MT ratio (MTR). The parameters in 1.5-tesla MRI system were as follows: TR, 50 msec; TE, 5 msec; flip angle, 30 degree; offset frequency of off-resonance MT pulse, 1000 Hz. The sequence was performed in 20 normal volunteers and 45 patients with brain tumors which were characterized histologically and surgically. The MTR for brain tumors was significantly lower than that for normal brain tissue (p < 0.05). The MTR for meningioma was higher than that for the other brain tumors (p < 0.05). In the meningiomas, MTR for fibrous type was higher than that for meningothelial type, but there was no statistical significance. Regarding the physical consistency for the brain tumors, as classified by surgery, there was a statistically significant difference in MTR between the soft tumor group (0.22 +/- 0.03, n = 6) and the hard tumor group (0.36 +/- 0.04, n = 10) (p < 0.01). This study suggested that the MT technique for patients with brain tumor may be useful to understand the characteristics of the tumors presurgically, based on the degree of intermolecular interaction of macromolecule such as protein.


Asunto(s)
Astrocitoma/diagnóstico , Neoplasias Encefálicas/diagnóstico , Imagen por Resonancia Magnética/métodos , Meningioma/diagnóstico , Adenoma/diagnóstico , Encéfalo/patología , Diagnóstico Diferencial , Humanos , Infiltración Leucémica , Linfoma/diagnóstico
16.
Jpn J Physiol ; 49(1): 27-33, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10219106

RESUMEN

Serum albumin has one reactive sulfhydryl (Cys-34) that is one of the important binding sites. Cys-34 is located in the crevice on the surface of the albumin molecule and is therefore restricted in its motion. Bovine serum albumin (BSA) Fraction V forms a transparent gel at pD 4.0 (F-form) in D2O at protein concentrations above 7% (BSA*-gel). We studied the molecular motion of Cys-34 on BSA in the solution and gel states by the vector electron paramagnetic resonance (EPR) method using a maleimide spin label. The rotational correlation times of the spin label bound to Cys-34 in the BSA solution and BSA*-gel were in the order of 10(-6) and 10(-5) s, respectively. A longer rotational correlation time of the Cys-34 spin label in the BSA*-gel suggested that the gel network formed in BSA may drastically slow the motion of Cys-34. The integrated value obtained from the vector EPR spectra also showed an extremely dramatic slowing of the Cys-34 spin label during the gel formation. On the other hand, the values for order parameter and the inclination of the principal axis (z) of the Cys-34 spin label to the rotational axis (mu) were the same in the BSA solution and BSA*-gel.


Asunto(s)
Albúmina Sérica Bovina/química , Compuestos de Sulfhidrilo/química , Animales , Bovinos , Cisteína , Espectroscopía de Resonancia por Spin del Electrón , Hidrólisis , Marcadores de Spin
17.
J Mol Biol ; 283(4): 731-9, 1998 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-9790836

RESUMEN

Whereas bovine beta-lactoglobulin is a predominantly beta-sheet protein, it has a marked alpha-helical preference and can be considered to be a useful model of the alpha-->beta transition, a key issue for understanding the folding and biological function of a number of proteins. In order to understand the mechanism of the alpha-->beta transition, the backbone structures of the recombinant bovine beta-lactoglobulin A in the native state and in the highly helical state induced by 2,2,2-trifluoroethanol were characterized by 1H, 13C and 15N multidimensional NMR spectroscopy. Overall, the secondary structures in the native state were similar to those of the crystal structure. On the other hand, beta-lactoglobulin in the 2,2,2-trifluoroethanol state was composed of many alpha-helical segments. The presence of the persistent alpha-helices in the helical state and the core beta-sheet in the native state suggested that during folding native-like core beta-sheet and several non-native helices are formed first and the remaining beta-sheet is subsequently "induced" through interaction with the pre-existing beta-sheet.


Asunto(s)
Lactoglobulinas/química , Animales , Bovinos , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Pliegue de Proteína , Estructura Secundaria de Proteína , Trifluoroetanol/farmacología
18.
Neurol Res ; 20(4): 313-9, 1998 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9618694

RESUMEN

We investigated the clinical applicability of pulsed off-resonance magnetization transfer (MT) technique in magnetic resonance (MR) imaging for the estimation of the histological feature of brain tumor. The parameters were optimized using bovine serum albumin (BSA) solutions and gels in 1.5-tesla MR system as follows: TR, 50 msec; TE, 5 msec; flip angle, 30 degree; offset frequency, 1000 Hz. MT effect was evaluated by measuring the MT ratio (MTR) and reconstructing calculated MTR color image. The MTRs of the BSA solutions and gels increased with increasing concentrations of protein, while the MTRs of the gels were remarkably higher than those of the solutions. The optimized sequence was performed in 20 healthy volunteers and 30 patients with brain tumors. In normal brains, the MTRs were significantly higher in white matter than in gray matter (p < 0.05). The MTR in brain tumor was significantly lower than that in normal brain tissue (p < 0.05) and the calculated MTR image produced contrast between brain tumor and normal brain tissue. There was a statistically significant difference in MTR between benign (0.30 +/- 0.05, n = 17) and malignant (0.26 +/- 0.04, n = 13) tumors (p < 0.05). The optimized MT technique is quite sensitive for estimating the degree of intermolecular interaction between macromolecules and water within the central nervous system.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Imagen por Resonancia Magnética/métodos , Color , Humanos , Procesamiento de Imagen Asistido por Computador , Valores de Referencia , Albúmina Sérica Bovina
19.
Neurol Res ; 20(3): 191-7, 1998 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9583578

RESUMEN

The purpose of this study is to estimate the clinical applicability of functional magnetic resonance imaging (f-MRI) combined with the activation study using single photon emission computerized tomography (SPECT) with special reference to identification of primary sensorimotor area. Five healthy volunteers and 5 patients with brain tumors located around the sensorimotor cortex were studied by both f-MRI with gradient echo and SPECT with 99mTc-ethyl cysteinate dimer using split-dose and subtraction method. In f-MRI study, the significant activation of the sensorimotor area was observed in all subjects. Various concurrent activation regions such as supplementary motor (2 volunteers vs. 4 patients), premotor (1 vs. 2) and ipsilateral sensorimotor area (1 vs. 2) were also observed. In the cases with the activation of neighboring regions of sensorimotor area, it was difficult to identify the area in f-MRI. In SPECT study, the sensorimotor area was depicted as the most increased area in regional cerebral blood flow in eight cases, the characteristics of which were helpful to diagnose the area, while significant activation of the area with edema could not be detected in two patients. Consequently, the sensorimotor area was cross-validated with both the modalities. This study demonstrated that it would be valuable to use both techniques for the clinical assessment of the sensorimotor area.


Asunto(s)
Mapeo Encefálico , Imagen por Resonancia Magnética , Corteza Motora/fisiología , Corteza Somatosensorial/fisiología , Tomografía Computarizada de Emisión de Fotón Único , Adulto , Anciano , Cisteína/análogos & derivados , Potenciales Evocados Somatosensoriales/fisiología , Femenino , Humanos , Periodo Intraoperatorio , Masculino , Persona de Mediana Edad , Corteza Motora/diagnóstico por imagen , Movimiento/fisiología , Compuestos de Organotecnecio , Radiofármacos , Corteza Somatosensorial/diagnóstico por imagen
20.
J Pept Res ; 52(6): 431-42, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9924988

RESUMEN

Helical content (f(alpha)) of bovine mercaptalbumin (BMA) showed the characteristic two-step decrease in the acidic region, one corresponding to the N-->F transition (pH 4.40-->3.75; f(alpha), 0.68-->0.58) and the other to the F-->E transition (the acid-expansion) (pH 3.60-->2.90; falpha, 0.58-->0.48). However, falpha of human serum albumin (HSA) mainly decreased in the N-->F transition (N-->F, pH 4.6-->3.4; falpha, 0.70-->-0.55 and F-->E, below pH 3.0; falpha, 0.55-->0.52). The difference in pH-profile of f(alpha) between BMA and HSA might be due to the microheterogeneity. The 1H-NMR spectra and cross-relaxation times (T(IS)) from irradiated to observed protein protons, which reflect the structural fluctuation and/or mobilability in proteins, were measured on the N-, F-, E-forms of HSA and BMA, and the N*-form (8.23 M urea, neutral pD) of iodoacetamide-blocked HSA (IA-HSA) and bovine serum albumin (IA-BSA). The 1H-NMR spectra and elongations of T(IS) values for the F- and E-forms of HSA and the E-form of BMA were quite similar to those for the N*-form of IA-HSA and IA-BSA, indicating the liberation of the intramolecular motion in the F- and E-forms. Those for the F-form of BMA were intermediate between the N- and E-form. The present results together with the reported data on hydrodynamic radii and D-H exchange reaction, indicate that the F-form of HSA and presumably BMA has a native-like globule form with a highly helical state and fluctuating tertiary structure. Thus, all of the present findings on the F-form of serum albumin seem to be in accord with the structural features for the F-form suggested by Foster's group (1-3, 19, 20, 22, 23) and the molten globule state demonstrated by Dolgikh et al. (40), and Ohgushi and Wada (36, 37).


Asunto(s)
Albúmina Sérica Bovina/química , Albúmina Sérica/química , Animales , Bovinos , Dicroismo Circular , Humanos , Concentración de Iones de Hidrógeno , Yodoacetamida/química , Espectroscopía de Resonancia Magnética , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...