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1.
Nature ; 464(7286): 262-6, 2010 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-20220845

RESUMO

The energy bandgap of an insulator is large enough to prevent electron excitation and electrical conduction. But in addition to charge, an electron also has spin, and the collective motion of spin can propagate-and so transfer a signal-in some insulators. This motion is called a spin wave and is usually excited using magnetic fields. Here we show that a spin wave in an insulator can be generated and detected using spin-Hall effects, which enable the direct conversion of an electric signal into a spin wave, and its subsequent transmission through (and recovery from) an insulator over macroscopic distances. First, we show evidence for the transfer of spin angular momentum between an insulator magnet Y(3)Fe(5)O(12) and a platinum film. This transfer allows direct conversion of an electric current in the platinum film to a spin wave in the Y(3)Fe(5)O(12) via spin-Hall effects. Second, making use of the transfer in a Pt/Y(3)Fe(5)O(12)/Pt system, we demonstrate that an electric current in one metal film induces voltage in the other, far distant, metal film. Specifically, the applied electric current is converted into spin angular momentum owing to the spin-Hall effect in the first platinum film; the angular momentum is then carried by a spin wave in the insulating Y(3)Fe(5)O(12) layer; at the distant platinum film, the spin angular momentum of the spin wave is converted back to an electric voltage. This effect can be switched on and off using a magnetic field. Weak spin damping in Y(3)Fe(5)O(12) is responsible for its transparency for the transmission of spin angular momentum. This hybrid electrical transmission method potentially offers a means of innovative signal delivery in electrical circuits and devices.

2.
Clin Exp Obstet Gynecol ; 43(2): 192-7, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27132408

RESUMO

PURPOSE: To investigate the relationship between the change of daily step counts and low back pain (LBP) during pregnancy. Materials and METHODS: Pregnant women at less than eight weeks of gestation (WG) were recruited. Daily step counts were measured with a pedometer. To assess LBP, the Oswestry disability index (ODI) score was recorded. Thirty-six individuals were divided into the LBP and non-LBP groups. The effect of step counts on LBP between the two groups was analyzed. RESULTS: At 16-19 WG, step counts were not considerably changed in the non-LBP group but were significantly increased in the LBP group. At 24-27 and 32-35 WG, step counts were increased in the non-LBP group but were significantly decreased in the LBP group. CONCLUSIONS: Acute increase of daily step counts in early pregnancy is a risk for LBP, and gradual increases of step counts after mid-pregnancy is recommended for women.


Assuntos
Dor Lombar/epidemiologia , Atividade Motora , Complicações na Gravidez/epidemiologia , Caminhada , Actigrafia , Adulto , Estudos de Coortes , Feminino , Humanos , Gravidez , Estudos Prospectivos
3.
Br J Cancer ; 111(11): 2082-90, 2014 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-25247323

RESUMO

BACKGROUND: The crosstalk between cancer cells and stroma is involved in the acquired capability for metastasis through the induction of epithelial-mesenchymal transition (EMT). We aimed to clarify the prognostic value of the histological category of EMT in colorectal cancer (CRC). METHODS: Tumour EMT was graded into one of three histological categories on the basis of integrated assessment of poorly differentiated clusters and pro-EMT desmoplasia at the leading edge of the primary tumour (Histology(EMT)). Stage II and III CRC patients (cohort 1, N=500) and stage IV patients (cohort 2, N=196) were retrospectively analysed. RESULTS: In cohort 1, patients were stratified into three groups with widely different disease-free survival rates (95%, 83% and 39%) on the basis of Histology(EMT) (P<0.0001). In cohort 2, Histology(EMT) significantly stratified overall survival of patients irrespective of metasectomy. Multivariate analyses indicated that Histology(EMT) had a strong prognostic impact independent of staging factors. Statistically, Histology(EMT) had a better prognostic stratification power than T and N stages; however, in cohort 2, the power of M substage was superior. CONCLUSIONS: A histological model to categorise EMT by integrated assessment of dedifferentiation and desmoplastic environment is a potent prognostic index independent of staging factors.


Assuntos
Neoplasias Colorretais/patologia , Transição Epitelial-Mesenquimal , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Desdiferenciação Celular , Neoplasias Colorretais/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico
4.
Nat Mater ; 12(6): 549-53, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23603850

RESUMO

When energy is introduced into a region of matter, it heats up and the local temperature increases. This energy spontaneously diffuses away from the heated region. In general, heat should flow from warmer to cooler regions and it is not possible to externally change the direction of heat conduction. Here we show a magnetically controllable heat flow caused by a spin-wave current. The direction of the flow can be switched by applying a magnetic field. When microwave energy is applied to a region of ferrimagnetic Y3Fe5O12, an end of the magnet far from this region is found to be heated in a controlled manner and a negative temperature gradient towards it is formed. This is due to unidirectional energy transfer by the excitation of spin-wave modes without time-reversal symmetry and to the conversion of spin waves into heat. When a Y3Fe5O12 film with low damping coefficients is used, spin waves are observed to emit heat at the sample end up to 10 mm away from the excitation source. The magnetically controlled remote heating we observe is directly applicable to the fabrication of a heat-flow controller.

5.
Phys Rev Lett ; 113(19): 196601, 2014 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-25415913

RESUMO

We report successful spin injection into the surface states of topological insulators by using a spin pumping technique. By measuring the voltage that shows up across the samples as a result of spin pumping, we demonstrate that a spin-electricity conversion effect takes place in the surface states of bulk-insulating topological insulators Bi(1.5)Sb(0.5)Te(1.7)Se(1.3) and Sn-doped Bi(2)Te(2)Se. In this process, the injected spins are converted into a charge current along the Hall direction due to the spin-momentum locking on the surface state.

6.
Physiol Res ; 73(2): 285-294, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38710059

RESUMO

This study aimed to determine whether electrical stimulation-based twitch exercise is effective in inhibiting the progression of immobilization-induced muscle fibrosis. 19 Wistar rats were randomly divided into a control group (n=6), an immobilization group (n=6; with immobilization only), and a Belt group (n=7; with immobilization and twitch exercise through the belt electrode device, beginning 2 weeks after immobilization). The bilateral soleus muscles were harvested after the experimental period. The right soleus muscles were used for histological analysis, and the left soleus muscles were used for biochemical and molecular biological analysis. As a result, in the picrosirius red images, the perimysium and endomysium were thicker in both the immobilization and Belt groups compared to the control group. However, the perimysium and endomysium thickening were suppressed in the Belt group. The hydroxyproline content and alpha-SMA, TGF-beta1, and HIF-1alpha mRNA expressions were significantly higher in the immobilization and belt groups than in the control group. These expressions were significantly lower in the Belt group than in the immobilization group. The capillary-to-myofiber ratio and the mRNA expressions of VEGF and PGC-1alpha were significantly lower in the immobilization and belt groups than in the control group, these were significantly higher in the Belt group than in the immobilization group. From these results, Electrical stimulation-based twitch exercise using the belt electrode device may prevent the progression of immobilization-induced muscle fibrosis caused by downregulating PGC-1alpha/VEGF pathway, we surmised that this intervention strategy might be effective against the progression of muscle contracture. Keywords: Immobilization, Skeletal muscle, Fibrosis, Electrical stimulation-based twitch exercise, PGC-1alpha/VEGF pathway.


Assuntos
Regulação para Baixo , Fibrose , Músculo Esquelético , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Fator A de Crescimento do Endotélio Vascular , Animais , Masculino , Ratos , Progressão da Doença , Estimulação Elétrica , Terapia por Estimulação Elétrica/métodos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Doenças Musculares/metabolismo , Doenças Musculares/patologia , Doenças Musculares/prevenção & controle , Doenças Musculares/etiologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Condicionamento Físico Animal/fisiologia , Ratos Wistar , Transdução de Sinais/fisiologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética
7.
Surg Case Rep ; 10(1): 13, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38196031

RESUMO

BACKGROUND: Locally recurrent rectal cancer (LRRC) involving the upper sacrum is typically incurable, and palliative treatment is the only option for most patients, resulting in a poor prognosis and reduced quality of life. Carbon ion radiotherapy (CIRT) has emerged as a promising modality for treating LRRC. This report presents a case of LRRC with sacral involvement that was managed via multidisciplinary therapy incorporating CIRT. CASE PRESENTATION: A 55-year-old male was diagnosed with an anastomotic recurrence of rectal cancer 15 months after undergoing anterior resection. Computed tomography (CT) suggested that the lesion was at an anastomosis site and broadly adherent to the upper sacrum, and colonoscopy confirmed the diagnosis of LRRC. Histopathological examination of the biopsy specimens revealed adenocarcinoma cells and that lesion was genetically RAS-wild. Induction chemotherapy with mFOLFOX6 and panitumumab was used as the first treatment. The recurrent lesion shrank and no signs of distant metastasis were observed after 11 cycles, although the range of the lesions attached to the sacrum remained unchanged. Therefore, we provided CIRT for this inoperable lesion and prophylactically removed the radiation-exposed bowel including the recurrent lesion, because radiation-induced ulcers can cause bleeding and perforation. Despite the presence of considerable fibrosis in the irradiated region, the operation was successful and the postoperative course had no untoward incidents. He is still recurrence-free 24 months following surgery, despite the lack of adjuvant chemotherapy. This is the first report of CIRT followed by CIRT-irradiated bowel removal for an unresectable anastomosis recurrent lesion. CONCLUSIONS: The clinical course of this case suggests that CIRT could be a potentially effective therapeutic option for LRRC involving the bowel, as long as the prophylactic removal of the irradiated bowel is performed at the optimal time. Further research involving larger sample sizes is warranted to validate the findings and conclusions of this case report.

8.
Phys Rev Lett ; 110(20): 206601, 2013 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-25167435

RESUMO

We report anisotropic magnetoresistance in Pt|Y(3)Fe(5)O(12) bilayers. In spite of Y(3)Fe(5)O(12) being a very good electrical insulator, the resistance of the Pt layer reflects its magnetization direction. The effect persists even when a Cu layer is inserted between Pt and Y(3)Fe(5)O(12), excluding the contribution of induced equilibrium magnetization at the interface. Instead, we show that the effect originates from concerted actions of the direct and inverse spin Hall effects and therefore call it "spin Hall magnetoresistance."

9.
Nat Mater ; 9(11): 894-7, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20871606

RESUMO

Thermoelectric generation is an essential function in future energy-saving technologies. However, it has so far been an exclusive feature of electric conductors, a situation which limits its application; conduction electrons are often problematic in the thermal design of devices. Here we report electric voltage generation from heat flowing in an insulator. We reveal that, despite the absence of conduction electrons, the magnetic insulator LaY(2)Fe(5)O(12) can convert a heat flow into a spin voltage. Attached Pt films can then transform this spin voltage into an electric voltage as a result of the inverse spin Hall effect. The experimental results require us to introduce a thermally activated interface spin exchange between LaY(2)Fe(5)O(12) and Pt. Our findings extend the range of potential materials for thermoelectric applications and provide a crucial piece of information for understanding the physics of the spin Seebeck effect.

10.
Phys Rev Lett ; 106(21): 216601, 2011 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-21699324

RESUMO

We experimentally show that exchange magnons can be detected by using a combination of spin pumping and the inverse spin-Hall effect proving its wavelength integrating capability down to the submicrometer scale. The magnons were injected in a ferrite yttrium iron garnet film by parametric pumping and the inverse spin-Hall effect voltage was detected in an attached Pt layer. The role of the density, wavelength, and spatial localization of the magnons for the spin pumping efficiency is revealed.

11.
BJS Open ; 4(4): 693-703, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32472647

RESUMO

BACKGROUND: Tumour budding is an important prognostic feature in early-stage colorectal cancer, but its prognostic significance in metastatic disease has not been fully investigated. METHODS: Patients with stage IV disease who had primary colorectal tumour resection without previous chemotherapy or radiotherapy from January 2000 to December 2018 were reviewed retrospectively. Budding was evaluated at the primary site and graded according to the criteria of the International Tumor Budding Consensus Conference (ITBCC) (BD1, low; BD2, intermediate; BD3, high). Patients were categorized by metastatic (M1a, M1b) and resectional (R0/R1, R2/unresected) status. Subgroups were compared for overall (OS) and recurrence-free (RFS) survival in R0/R1 subgroups; R2/unresected patients were evaluated for the rate of tumour progression, based on change in tumour size from baseline. RESULTS: Of 371 patients observed during the study, 362 were analysed. Patients with BD3 had a lower 5-year OS rate than those with BD1 + BD2 (18·4 versus 40·5 per cent; P < 0·001). Survival analyses according to metastatic and resection status also showed that BD3 was associated with shorter OS than BD1 + BD2. In multivariable analysis, BD3 (hazard ratio (HR) 1·51, 95 per cent c.i. 1·11 to 2·10; P = 0·009), T4 status (HR 1·39) and R2/unresected status (HR 3·50) were associated with decreased OS. In the R0/R1 subgroup, the 2-year RFS rate was similar for BD3 and BD1 + BD2 according to metastatic status. There was no significant difference between BD3 and BD1 + BD2 for change in tumour size in the R2/unresected subgroup (P = 0·094). Of 141 patients with initially unresectable metastases who had chemotherapy, 35 achieved conversion from unresectable to resectable status. The conversion rate was significantly higher for BD1 + BD2 than for BD3 (36 versus 18 per cent; P = 0·016). CONCLUSION: Stage IV colorectal cancer with high-grade tumour budding according to ITBCC criteria correlates with poor prognosis.


ANTECEDENTES: La esofaguectomía por cáncer se asocia con un descenso de la calidad de vida relacionada con la salud (health-related quality of life, HRQoL) a largo plazo. El objetivo de este estudio fue evaluar el efecto de las comorbilidades sobre la HRQOL entre pacientes supervivientes de cánceres de esófago o de la unión gastroesofágicas después de 10 años o más. MÉTODOS: Este estudio incluye una cohorte de base poblacional recogida de forma prospectiva que incluía todos los pacientes operados de cáncer de esófago o de la unión gastroesofágica en Suecia en 2001-2005 con seguimiento hasta el 31 de diciembre de 2016. Todos los datos relacionados con las características de los pacientes y del tumor, detalles del tratamiento y HRQoL se recogieron en una base de datos prospectiva. Se utilizaron modelos de regresión multivariable ANCOVA, ajustados por edad, sexo, histología del tumor, estadio, y técnica quirúrgica, para calcular las puntuaciones medias ajustadas con los i.c. del 95% para todas las variables de la HRQoL. RESULTADOS: Un total de 92 (88%) supervivientes respondieron a los cuestionarios. En función del impacto de las comorbilidades en la salud en general, se clasificaron a los pacientes en los grupos de bajo versus alto impacto. Los resultados muestran que los pacientes en el grupo de alto impacto presentaban un descenso clínicamente significativo de la HRQoL y un aumento en el nivel de síntomas, pero las diferencias entre estos dos grupos no fueron estadísticamente significativas. CONCLUSIÓN: A los 10 años de la esofaguectomía por cáncer, las comorbilidades con un alto impacto sobre la salud general siguen contribuyendo en el deterioro de la HRQoL.


Assuntos
Neoplasias Colorretais/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/mortalidade , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida
12.
BJS Open ; 4(2): 301-309, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32026629

RESUMO

BACKGROUND: Reduced expression of cluster of differentiation (CD) 133 and cyclo-oxygenase (COX) 2, and increased density of CD8+ tumour-infiltrating lymphocytes, are associated with a favourable tumour response to preoperative chemoradiotherapy (CRT). This study aimed to evaluate these markers in relation to tumour response after preoperative CRT in two rectal cancer cohorts. METHODS: Patients with low rectal cancer who underwent radical resection and preoperative short-term CRT in 2001-2007 (retrospective cohort) and long-term CRT in 2011-2017 (prospective cohort) were analysed. Pretreatment biopsies were stained immunohistochemically using antibodies to determine CD133 and COX-2 expression, and increased CD8+ density. Outcome measures were tumour regression grade (TRG), tumour downstaging and survival. RESULTS: For 95 patients in the retrospective cohort, the incidence of TRG 3-4 was 67 per cent when two or three immunohistochemistry (IHC) features were present, but only 20 per cent when there were fewer features (P < 0·001). The incidence of tumour downstaging was higher in patients with at least two IHC features (43 versus 22 per cent with fewer features; P = 0·029). The 49 patients in the prospective cohort had similar rates to those in the retrospective cohort (TRG 3-4: 76 per cent for two or more IHC features versus 25 per cent with fewer features, P < 0·001; tumour downstaging: 57 versus 25 per cent respectively, P = 0·022). Local recurrence-free survival rates in patients with more or fewer IHC features were similar in the retrospective and prospective cohort (P = 0·058 and P = 0·387 respectively). CONCLUSION: Assessment of CD133, COX-2 and CD8 could be useful in predicting a good response to preoperative CRT in patients with lower rectal cancer undergoing neoadjuvant therapy. Further studies are needed to validate the results in larger cohorts and investigate a survival benefit.


ANTECEDENTES: La expresión reducida de CD133 and COX-2, y un aumento en la densidad de los linfocitos infiltrantes del tumor CD8+ se han asociado recientemente con una respuesta favorable del tumor a la quimiorradioterapia preoperatoria (preoperative chemoradiotherapy, CRT). Este estudio evaluó estos marcadores respecto a la respuesta del tumor tras CRT preoperatoria en dos cohortes de cáncer colorrectal. MÉTODOS: Se analizaron pacientes con cáncer de recto bajo sometidos a resección radical y CRT preoperatoria de corta duración entre 2001-2007 (cohorte retrospectiva) y CRT de larga duración entre 2011-2017 (cohorte prospectiva). Se realizó tinción inmunohistoquímica (immunohistochemical, IHC) con anticuerpos para CD133, COX-2 y CD8 en las biopsias previas al tratamiento. Las características de interés incluyeron la disminución en las expresiones de CD133 y COX-2, y la densidad aumentada de CD8+. Las variables de interés fueron los grados de regresión tumoral (tumour regression grades, TRG) de acuerdo con Rödel, la reducción del estadio tumoral y las supervivencias. RESULTADOS: La cohorte retrospectiva incluyó 95 pacientes. En este subgrupo, la incidencia de TRGs 3-4 fue del 66,7% en pacientes con dos o tres características de la IHC, mientras que solo fue del 20,0% en pacientes con ninguna o con una característica (P < 0,001). Además, la incidencia de disminución del estadio tumoral fue más alta en pacientes que mostraban al menos dos características IHC (43,3%) que en los controles (21,5%; P = 0,029). En la cohorte prospectiva se incluyeron 49 pacientes y la incidencia de estos hallazgos fue similar (TRG 3-4, 76,2% en ≥ 2 características IHC versus 25,0% en los controles, P < 0,001; disminución del estadio tumoral, 57,1% en ≥ 2 características IHC versus 25,0% en los controles, P = 0,022). La supervivencia libre de recidiva local fue similar en las cohortes retrospectiva y prospectiva, cuando se compararon subgrupos de acuerdo con las características IHC (P = 0,058 y 0,387, respectivamente) CONCLUSIÓN: Este estudio sugiere que la evaluación de CD133, COX-2 y CD8 podría ser útil para la predicción de una buena respuesta a la CRT preoperatoria en pacientes con cáncer de recto bajo sometidos a tratamiento neoadyuvante. Se necesitan estudios adicionales para validar los resultados en amplias cohortes e investigar el beneficio en la supervivencia.


Assuntos
Quimiorradioterapia Adjuvante/métodos , Linfócitos do Interstício Tumoral/imunologia , Neoplasias Retais/imunologia , Neoplasias Retais/terapia , Antígeno AC133/imunologia , Idoso , Antígenos de Neoplasias/imunologia , Linfócitos T CD8-Positivos/imunologia , Ciclo-Oxigenase 2/imunologia , Intervalo Livre de Doença , Feminino , Humanos , Imuno-Histoquímica , Japão , Linfócitos do Interstício Tumoral/metabolismo , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante/métodos , Valor Preditivo dos Testes , Estudos Prospectivos , Neoplasias Retais/metabolismo , Neoplasias Retais/mortalidade , Estudos Retrospectivos , Resultado do Tratamento
13.
Colorectal Dis ; 11(9): 951-9, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19175655

RESUMO

OBJECTIVE: To determine the clinical value of evaluating the cancer morphology in muscularis propria (MP) for colorectal cancer (CRC) patients. METHOD: A total of 994 patients with advanced CRC were reviewed in terms of two distinctive growth patterns in the MP: (i) horizontal spread between the circular and longitudinal muscle layers (H-spread) and (ii) 'streaming' spread between the muscle bundles of the circular muscle layer (S-spread). RESULTS: The incidence of H-spread (n = 153) and S-spread (n = 150) showed a positive correlation with tumour-node-metastasis (TNM) stage and both exerted a negative impact on postoperative survival. Adverse morphology in the MP (H-spread and/or S-spread) was consistent with a high grade of vascular invasion and budding in the extramural layer, as also with unfavourable fibrotic stromas in the reactive fibrous zone; the 5-year survival rate in patients with such features was 64.2%, which was lower than that in those without (86.5%, P < 0.0001). Multivariate analysis demonstrated that adverse morphology was an independent prognostic determinant, along with T- and N -stage. As the mode of H-spread, perineural invasion in the myenteric plexus was found to be predominant over lymphatic spread on the basis of S100 and CD34 immunostaining, but neural cell adhesion molecule expression, whether on cancer cells or on neural cells, was not significant for this growth pattern. CONCLUSION: A particular group of CRCs ingeniously utilizes the thin space between muscle fascicles for development in the MP. Although the biological mechanism remains unknown, this distinctive growth pattern could be a useful indicator to identify CRC patients at high risk of recurrence.


Assuntos
Adenocarcinoma/patologia , Neoplasias Colorretais/patologia , Músculo Liso/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Metástase Linfática/patologia , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Valor Preditivo dos Testes , Prognóstico , Análise de Sobrevida , Adulto Jovem
14.
Biochim Biophys Acta ; 1548(2): 220-8, 2001 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-11513967

RESUMO

Apparent Ca(2+)-binding constant (K(app)) of Caenorhabditis elegans troponin C (CeTnC) was determined by a fluorescence titration method. The K(app) of the N-domain Ca(2+)-binding site of CeTnC was 7.9+/-1.6 x 10(5) M(-1) and that of the C-domain site was 1.2+/-0.6 x 10(6) M(-1), respectively. Mg(2+)-dependence of the K(app) showed that both Ca(2+)-binding sites did not bind competitively Mg(2+). The Ca(2+) dissociation rate constant (k(off)) of CeTnC was determined by the fluorescence stopped-flow method. The k(off) of the N-domain Ca(2+)-binding site of CeTnC was 703+/-208 s(-1) and that of the C-domain site was 286+/-33 s(-1), respectively. From these values we could calculate the Ca(2+)-binding rate constant (k(on)) as to be 5.6+/-2.8 x 10(8) M(-1) s(-1) for the N-domain site and 3.4+/-2.1 x 10(8) M(-1) s(-1) for the C-domain site, respectively. These results mean that all Ca(2+)-binding sites of CeTnC are low affinity, fast dissociating and Ca(2+)-specific sites. Evolutional function of TnC between vertebrate and invertebrate and biological functions of wild type and mutant CeTnCs are discussed.


Assuntos
Caenorhabditis elegans/metabolismo , Cálcio/metabolismo , Troponina C/metabolismo , Aminoquinolinas , Animais , Sítios de Ligação , Evolução Molecular , Corantes Fluorescentes , Cinética , Mutação , Espectrometria de Fluorescência , Titulometria , Troponina C/genética
15.
J Mol Biol ; 305(4): 829-38, 2001 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-11162095

RESUMO

The hnRNP C protein tetramer cooperatively binds 230 nt increments of pre-mRNA in vitro in a salt-resistant manner and is located along the length of vertebrate transcripts in vivo. Based on these and other findings it has been suggested that hnRNP C functions as a chaperonin to maintain long lengths of RNA topologically single-stranded and accessible to splicing factors. We report here that human C protein is lethal when expressed in the yeast Saccharomyces cerevisiae. Through a series of fluorescent immunolocalization studies, lethality was observed to be associated with the rapid nuclear accumulation of both C protein and yeast pre-mRNA. Studies using various protein constructs and the two hybrid assay reveal that these events are dependent on the basic 40 residue high-affinity RNA binding domain and its contiguous leucine zipper-like motif (the bZLM, residues 140-214). Additionally, equilibrium binding studies have shown that the bZLM is the determinant of C protein's salt-resistant RNA binding mode. Taken together, these findings further distinguish the bZIP-like domain as the major determinant of C protein's high-affinity interaction with RNA, oligomerization, and its highly cooperative RNA binding activity. Finally, these findings indicate that yeast and vertebrates may possess a conserved mechanism for general import of RNP although a true homolog to vertebrate C protein appears not to exist in yeast. Lethality is likely due to the absence in yeast of specific mechanisms for the removal of human C protein from nascent transcripts.


Assuntos
Núcleo Celular/metabolismo , Genes Letais/genética , Precursores de RNA/metabolismo , RNA Fúngico/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/metabolismo , Saccharomyces cerevisiae/genética , Transporte Ativo do Núcleo Celular , Motivos de Aminoácidos , Dicroísmo Circular , Fluorescência , Ribonucleoproteínas Nucleares Heterogêneas Grupo C , Ribonucleoproteínas Nucleares Heterogêneas , Humanos , Hibridização In Situ , Zíper de Leucina , Ligação Proteica/efeitos dos fármacos , Estrutura Quaternária de Proteína , Precursores de RNA/genética , RNA Fúngico/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Ribonucleoproteínas/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Sais/farmacologia , Deleção de Sequência/genética , Termodinâmica
16.
J Leukoc Biol ; 57(1): 129-34, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7829964

RESUMO

Aminopeptidase (APN) was found to degrade interleukin-8 (IL-8) and inactivate its chemotactic activity. The chemotactic activity of IL-8 was decreased by APN or neutrophil plasma membranes dose- and time-dependently. The chemotactic activity was not inactivated in the presence of bestatin or WM15 monoclonal antibody. The expression of IL-8 was measured by flow cytometry. On lipopolysaccharide (LPS) stimulation, IL-8 expression increased for 60 min and then decreased markedly. In contrast, on treatment with LPS and bestatin, the expression of IL-8 increased continuously for at least 120 min. These results suggest that the expression and release of IL-8 from phagocytic cells are regulated by the proteolytic effect of APN on IL-8.


Assuntos
Antígenos CD13/farmacologia , Interleucina-8/antagonistas & inibidores , Animais , Anticorpos Monoclonais/farmacologia , Antígenos CD13/metabolismo , Membrana Celular/fisiologia , Quimiotaxia de Leucócito/fisiologia , Relação Dose-Resposta a Droga , Eletroforese em Gel de Poliacrilamida , Citometria de Fluxo , Humanos , Interleucina-8/metabolismo , Interleucina-8/fisiologia , Leucina/análogos & derivados , Leucina/farmacologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/fisiologia , Lipopolissacarídeos/farmacologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Neutrófilos/fisiologia , Inibidores de Proteases/farmacologia , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/metabolismo , Suínos , Fatores de Tempo
17.
FEBS Lett ; 304(2-3): 163-6, 1992 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-1319924

RESUMO

The in vitro potency of neopterin (NP) as an antioxidant and its in vivo activity to suppress alloxan-induced diabetes were investigated. The reduced form of neopterin, 5,6,7,8-tetrahydroneopterin (NPH-4), showed an extremely high superoxide anion radical scavenging activity in two assay systems, i.e. xanthine/xanthine oxidase- and macrophage/phorbol myristate acetate (PMA)-reaction systems. NPH-4 also inhibited the oxidation of linoleic acid about as effectively as uric acid. Furthermore, NPH-4 and NP effectively suppressed alloxan-induced mouse diabetes. These results suggest that pteridines play an important role as endogenous antioxidants.


Assuntos
Antioxidantes/farmacologia , Biopterinas/análogos & derivados , Diabetes Mellitus Experimental/metabolismo , Aloxano/farmacologia , Animais , Biopterinas/farmacologia , Glicemia/análise , Diabetes Mellitus Experimental/induzido quimicamente , Masculino , Camundongos , Neopterina , Pteridinas/farmacologia , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo , Xantina Oxidase/metabolismo
18.
FEBS Lett ; 329(1-2): 125-8, 1993 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-8394827

RESUMO

The effect of the oxidized form of neopterin (NP) on the NADPH-dependent superoxide-generating oxidase (NADPH-oxidase) was investigated in both whole-cell and cell-free activation systems by using peritoneal macrophages of rats which had received an intraperitoneal injection of mineral oil. In the whole-cell system, NP remarkably inhibited the generation of superoxides in macrophages stimulated with phorbol myristate acetate (PMA). NP also showed an significant suppression of the activation of superoxide-generating NADPH-oxidase in the cell-free system using solubilized membranes and sodium dodecyl sulfate (SDS) as a stimulant. The 50%-inhibitory concentration (IC50) of NP was about 1 microM in both assay systems. In a kinetic study, competitive inhibition of the NADPH-oxidase by NP was observed in the cell-free system with a calculated inhibition constant (Ki) of 6.50 microM. These findings suggest that NP may play an important role in the suppression of superoxide generation via the inhibition of the NADPH-oxidase in phagocytes.


Assuntos
Biopterinas/análogos & derivados , Macrófagos/enzimologia , NADH NADPH Oxirredutases/antagonistas & inibidores , NADP/farmacologia , Superóxidos/metabolismo , Animais , Ligação Competitiva , Biopterinas/farmacologia , Cálcio/metabolismo , Sistema Livre de Células , NADH NADPH Oxirredutases/metabolismo , NADPH Oxidases , Neopterina , Cavidade Peritoneal/citologia , Proteína Quinase C/metabolismo , Ratos , Dodecilsulfato de Sódio/farmacologia , Acetato de Tetradecanoilforbol/farmacologia , Xantina , Xantina Oxidase/metabolismo , Xantinas/metabolismo
19.
J Hypertens ; 14(4): 453-9, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8761894

RESUMO

OBJECTIVE: An animal model of HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome was developed by means of stimulation of the celiac ganglion in rats. METHODS: The celiac ganglion in pregnant or non-pregnant rats was exposed to endotoxin (lipopolysaccharide, LPS) (500 micrograms/50 microliters), potassium chloride (0.2 mol/l/50 microliters), or saline solution (50 microliters). In another group of rats the bifurcation of the abdominal aorta was exposed to LPS (500 micrograms/50 microliters). Blood pressure, platelet count, hematocrit, serum aspartate transaminase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH), and plasma norepinephrine and epinephrine were measured for 6 h after treatment. Histopathologic studies were also performed in these rats. RESULTS: A significant increase in blood pressure, AST, ALT, LDH, norepinephrine, and epinephrine was found in the endotoxin-treated pregnant rats compared with control rats treated with the saline solution. A significant decrease in platelet count was found in endotoxin-treated pregnant rats compared with the control rats. A significant increase in blood pressure, AST, norepinephrine, and epinephrine was found in the potassium chloride-treated pregnant rats compared with control rats. Blood pressure and biochemical parameters remained unchanged in the pregnant rats treated with LPS at the bifurcation of the abdominal aorta, as in those treated with saline at the celiac ganglion. Histologic examination of liver tissues treated with LPS or potassium chloride showed varying degrees of ischemic necrosis of hepatocytes similar to that observed in the human HELLP syndrome. Blood pressure, biochemical parameters, and histologic findings in non-pregnant rats were almost the same as those in pregnant rats. CONCLUSION: This study suggests that exogenous stimulation of the celiac ganglion causes an increase in the blood pressure and liver ischemia, resulting in HELLP syndrome-like disease in pregnant and non-pregnant rats.


Assuntos
Gânglios Simpáticos/fisiologia , Síndrome HELLP/etiologia , Animais , Pressão Sanguínea , Feminino , Humanos , Lipopolissacarídeos/farmacologia , Fígado/patologia , Masculino , Gravidez , Ratos , Ratos Endogâmicos WKY
20.
Thromb Haemost ; 84(4): 583-90, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11057854

RESUMO

A double-blind, randomized, placebo-controlled trial was conducted to evaluate whether treatment with Antithrombin (AT) concentrates improved the clinical and perinatal outcome in patients with severe preeclampsia. Severe preeclamptic patients (24 to 35 weeks of gestation. Gestosis Index (GI) > or = 6 points) were randomized into two groups: 66 received AT and 67 received placebo. There were no statistical differences in the clinical profiles of the two groups. Study drugs were given intravenously once daily for 7 consecutive days. Maternal symptoms were evaluated from the difference of GI between before and after treatment, and fetal findings were evaluated from the changes of the biophysical profile score and the estimated fetal weight gain. Improvement was significantly greater in the AT group for both the GI (p = 0.020) and the estimated fetal weight gain (p = 0.029). The improvement of coagulation parameters was also evaluated. The D-dimer levels increased significantly in the placebo group (p = 0.026), but did not change in the AT group. Gestation was significantly prolonged (p = 0.007), and the number of low-birth weight infants was significantly smaller (p = 0.011) in the AT group. No adverse events related to AT were observed. It is revealed that AT concentrate therapy for preeclampsia is effective and safe, leading to an improved perinatal outcome.


Assuntos
Anticoagulantes/administração & dosagem , Antitrombinas/administração & dosagem , Pré-Eclâmpsia/tratamento farmacológico , Complicações Cardiovasculares na Gravidez/tratamento farmacológico , Doença Aguda , Adulto , Método Duplo-Cego , Feminino , Humanos , Gravidez , Resultado da Gravidez , Resultado do Tratamento
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