Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Phys Rev Lett ; 128(5): 051102, 2022 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-35179919

RESUMO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

2.
Zhonghua Fu Chan Ke Za Zhi ; 56(9): 616-621, 2021 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-34547862

RESUMO

Objective: To investigate the present situation of unintended pregnancy within two years postpartum and its influencing factors in China. Methods: Participants who delivered a live birth at 60 hospitals in 15 provinces in the eastern, central and western regions of China during July 2015 to June 2016 were interviewed by using structured questionnaire. Information on occurrence of unintended pregnancy within 2 years after delivery, postpartum contraceptive use, sexual resumption, breastfeeding, and women's socio-demographic characteristics, and so on, were collected. Life-table analysis, cluster log-rank tests and a 2-level Cox regression model were used for data analysis. Results: A total of 18 045 postpartum women were investigated. The cumulative 1- and 2-year unintended pregnancy rates after delivery were 5.3% (95%CI: 4.5%-6.1%) and 13.1% (95%CI: 11.3%-14.8%), respectively. Cox regression model analysis showed that the risk of unintended pregnancy within 2 years postpartum were increased in younger women, ethnic minorities, women with abortion history, and those who had a vaginal delivery with short lactation time and late postpartum contraceptive initiation (all P<0.01). The risk of postpartum unintended pregnancy was not associated with geographic regions and hospitals where women gave a birth (all P>0.05). Conclusions: In China, the risk of unintended pregnancy within 2 years after delivery is relatively high. Service institutions and service providers should improve the quality of postpartum family planning services, promote the use of high effect contraceptive methods, and educate women to use a method at the time of their sexual resumption or even before.


Assuntos
Anticoncepção , Gravidez não Planejada , China/epidemiologia , Serviços de Planejamento Familiar , Feminino , Humanos , Incidência , Gravidez
3.
Science ; 373(6553): 425-430, 2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34261813

RESUMO

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 1036 ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

4.
Phys Rev Lett ; 126(24): 241103, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34213924

RESUMO

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25 TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160 TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

5.
Nature ; 594(7861): 33-36, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34002091

RESUMO

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

6.
Zhonghua Yan Ke Za Zhi ; 56(5): 343-348, 2020 May 11.
Artigo em Chinês | MEDLINE | ID: mdl-32450666

RESUMO

Objective: To observe the preliminary clinical effect of intraocular lens optic capture through posterior continuous curvilinear capsulorhexis in the treatment of pediatric cataract. Methods: It was a retrospective case series study. Forty-three eyes of 28 children underwent posterior continuous curvilinear capsulorhexis with posterior chamber intraocular lens optic capture to treat cataract from June 2017 to October 2018 in Qingdao Eye Hospital. Postoperative best corrected visual acuity, diopters, intraocular pressure, the position of intraocular lens, and postoperative complications were assessed. The distribution of preoperative and postoperative best corrected visual acuity was analyzed by Fisher's exact probability test. Results: Twenty-eight patients were 14 females and 14 males aged from 2 years old to 12 years old [mean age, (7±4) years]. All intraocular lenses were successfully captured in the posterior capsule. Patients were followed-up for 6.0 to 12.0 months (mean, 8.4 months). Except 2 eyes from one uncooperative child, the distribution of preoperative and postoperative best corrected visual acuity (<0.1, 0.1-<0.3, 0.3-<0.5, ≥0.5) had a significant difference (17, 17, 4, 3 eyes vs. 4, 4, 5, 28 eyes, P<0.01). At the last postoperative follow-up visit, the mean spherical equivalent was (0.21±0.74) D. Transient intraocular hypertension occurred in 3 eyes at 1 week after surgery and was controlled with stopping the use of corticosteroid eyedrops. No visual axis opacification or intraocular lens decentration or tilt was observed during the follow-up period. No other complications such as iris synechia, secondary glaucoma, retinal detachment, and cystoid macular edema were observed. Conclusions: Posterior continuous curvilinear capsulorhexis with intraocular lens optic capture is a safe and effective technique to treat pediatric cataract. It has a significant effect on the prevention of visual axis opacification after cataract surgery in children. (Chin J Ophthalmol, 2020, 56: 343-348).


Assuntos
Capsulorrexe , Extração de Catarata , Catarata , Lentes Intraoculares , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Implante de Lente Intraocular , Masculino , Complicações Pós-Operatórias , Estudos Retrospectivos
7.
Public Health ; 180: 90-99, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31875529

RESUMO

OBJECTIVE: We aimed to predict population composition, mortality, sociodemographic index (SDI), and cause-specific disability-adjusted life year (DALY) rate in China from 2018 through 2021. STUDY DESIGN: Using the time series method autoregressive integrated moving average (ARIMA) models on all available data, mainly Statistics Year Report by the Global Burden of Disease Study 2017, we predicted populations, deaths, DALYs attributable to disease conditions, and injuries (causes) for China from 2018 through 2021 at levels 0, 1, 2, and 3. METHODS: The time series method ARIMA models was used on history data. RESULTS: The predicted total population and SDI in China are increasing from 2018 through 2021. The under-5 mortality is decreasing; from 10.24% to 0.65% in the period 1990-2021. The all-cause DALY rate decreases. The top causes of DALY rate are non-communicable diseases (level 1), cardiovascular diseases (level 2), and stroke (level 3). For the leading 22 level 2 causes in 2018, the trend of ranking in 2021 is as follows: unchanged, 15; increasing, 4; and decreasing, 3. For the leading 169 level 3 causes in 2018, the trend of ranking in 2021 is: as follows: unchanged, 49; increasing, 63; and decreasing 57. CONCLUSIONS: Cause-specific and time-dependent health policy should be steered to reduce the major burden focuses and to improve population health.


Assuntos
Pessoas com Deficiência/estatística & dados numéricos , Anos de Vida Ajustados por Qualidade de Vida , Doenças Cardiovasculares/epidemiologia , China/epidemiologia , Humanos , Modelos Estatísticos , Doenças não Transmissíveis/epidemiologia , Acidente Vascular Cerebral/epidemiologia
8.
Zhonghua Fu Chan Ke Za Zhi ; 51(8): 576-80, 2016 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-27561935

RESUMO

OBJECTIVE: To investigate the factors affecting the vaginal birth after cesarean (VBAC). METHODS: Totaly 298 women who underwent trial of labor after cesarean section (TOLAC) from Jan 2015 to Dec 2015 were recruited from Beijing Obstetrics and Gynecology Hospital, FuXing Hospital, Tongzhou Maternal and Child Health Hospital of Beijing, the Second Affiliated Hospital of Chongqing Medical University and the People's Hospital of Chengyang District of Qingdao. The maternal age, the interval from the last cesarean section, the body mass index (BMI) before pregnancy, the weight gain during pregnancy, the way into labor, the Bishop score before labor, the gestational age and the birth weight of the neonate were recorded in a self-made form. The factors affecting VBAC were analyzed by univariate analysis and multivariable logistic regression. RESULTS: (1)The incidence of VBAC, uterine rupture, postpartum hemorrhage and neonatal asphyxia were 70.5% (210/298), 2.7% (8/298), 9.4% (28/298) and 1.3% (4/298), respectively. No maternal death and perinatal death occurred. (2)The univariate analysis suggested that the maternal age, the BMI before pregnancy, the Bishop score before labor, the labor induction, the gestational age at delivery and the neonatal weight were factors affecting VBAC. The maternal age and the Bishop score before labor were significantly higher in the VBAC group than in the unsuccessful TOLAC group(P<0.05). While the BMI before pregnancy, the induction rate, the gestational weeks at delivery and the birth weight of the neonate were significantly lower in the VBAC group than in the unsuccessful TOLAC group (P<0.05). Multivariable logistic regression analysis showed that successful VBAC was affected by the maternal age, the BMI before pregnancy, the Bishop score before labor and the birth weight of the neonates(P<0.05). CONCLUSION: The maternal age, the BMI before pregnancy, the Bishop score before labor and the birth weight of neonate are the main factors affecting VBAC.


Assuntos
Índice de Massa Corporal , Cesárea/estatística & dados numéricos , Idade Materna , Prova de Trabalho de Parto , Nascimento Vaginal Após Cesárea/estatística & dados numéricos , Peso ao Nascer , China/epidemiologia , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Trabalho de Parto Induzido , Modelos Logísticos , Obesidade/complicações , Hemorragia Pós-Parto , Gravidez , Resultado da Gravidez , Estudos Retrospectivos , Ruptura Uterina , Nascimento Vaginal Após Cesárea/efeitos adversos , Ganho de Peso , Adulto Jovem
9.
Zhonghua Liu Xing Bing Xue Za Zhi ; 37(5): 597-9, 2016 May.
Artigo em Chinês | MEDLINE | ID: mdl-27188345

RESUMO

OBJECTIVE: To evaluate the performance of Zika virus(ZIKV)disease prevention and control. METHODS: Descriptive epidemiological analysis was conducted on the clinical manifestations, laboratory detection results and disease progression of the third imported ZIKV disease case in the mainland of China. RESULTS: On 19 February 2016, a ZIKV disease case was confirmed in Yiwu, Zhejiang province, which was the third imported case of ZIKV disease confirmed by China CDC laboratory and expert consulting. The patient just had a travel to Fiji and Samoa and had mosquito bite history in Samoa. The patient was hospitalized on 16 February after the onset on 14 February and the eruption on 15 February. The body temperature of the patient became normal on 17 February, the rash disappeared on 19 February and the conjunctivitis resolved on 20 February. The positive detection of the viral nucleic acid in blood was only for 3 consecutive days, and the viral nucleic acid could be detected in urine even after negative detection in blood for 4 days. CONCLUSION: The symptoms of the patient were typical. ZIKV can be detected by using blood sample in early phase, but after body temperature become normal, the virus can be detected in urine.


Assuntos
RNA Viral/sangue , Viagem , Infecção por Zika virus/diagnóstico , Zika virus/isolamento & purificação , China , Progressão da Doença , Fiji , Humanos , Laboratórios , Encaminhamento e Consulta , Samoa , Testes Sorológicos , Inquéritos e Questionários , Infecção por Zika virus/sangue , Infecção por Zika virus/virologia
10.
J Anesth ; 30(3): 410-9, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26762997

RESUMO

PURPOSE: Heat stress stimulation can cause various injuries in human umbilical vein endothelial cells (HUVEC), including apoptotic cell death and an increase in cell permeability. Propofol (PPF), a commonly used anesthetic, is known to have an important role in antioxidation as well as organ protection. Therefore, our aim is to evaluate the protective effects of PPF on heat stress (HS)-induced oxidative stress injury and its possible mechanism of action. METHODS: For HS + PPF, cells were treated with propofol followed by 2 h heat stress at 43 °C and then 4 h incubation under normal conditions. For propofol treatment, HUVEC were cultured in serum-free Dulbecco's modified Eagle medium supplemented with 0, 10, 25, or 50 µM propofol for 6 h under normal conditions. RESULTS: During the study, we found that, in HS-induced cellular damage, the protective effect of propofol was related closely with its antioxidation properties. We further revealed that heat stress significantly reduced the level of manganese superoxide demutase (MnSOD) and Cu/Zn SOD, but that propofol could inhibit the reduction of MnSOD only. Transfection of HUVEC with MnSOD small interfering RNA (siRNA) markedly decreased the expression of MnSOD, and the protective effect of propofol in the MnSOD siRNA clones was significantly reduced. CONCLUSION: Propofol protected the heat stress-injured cells, at least partly, through upregulating MnSOD expression, effectively reducing the direct or indirect cell damage caused by oxidative stress.


Assuntos
Anestésicos Intravenosos/farmacologia , Antioxidantes/farmacologia , Transtornos de Estresse por Calor/enzimologia , Transtornos de Estresse por Calor/prevenção & controle , Propofol/farmacologia , Superóxido Dismutase/metabolismo , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Feminino , Células Endoteliais da Veia Umbilical Humana , Humanos , Estresse Oxidativo/efeitos dos fármacos , RNA Interferente Pequeno/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/genética
11.
Genet Mol Res ; 13(1): 2231-9, 2014 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-24737471

RESUMO

Our previous studies have indicated that mouse bone marrow mesenchymal stem cells (mBMMSCs) have potential to differentiate into hepatocytes with high efficiency. Our study aimed to evaluate the role of the mouse histone methyltransferase enhancer of zeste homolog 2 gene (EZH2) in the hepatocellular differentiation of mBMMSCs. The mBMMSCs isolated from femurs and tibias were cultured in Iscove's modified Eagle's medium (IMEM) supplemented with 10% fetal bovine serum. Hepatocellular differentiation was induced by 20 ng/mL hepatocyte growth factor and 10 ng/mL fibroblast growth factor 4. The mouse histone methyltransferase EZH2 gene was introduced via PLenti-eGFP-EZH2 or PLenti-eGFP-NEO as a control. Hepatocellular-induced mBMMSCs showed lower expression of EZH2 and lower level of histone H3 lysine 27 trimethylation (H3K27me3) in the AFP and FOXa2 gene promoter regions compared to uninduced mBMMSCs. Introduction of EZH2 inhibited hepatocellular induction, reduced both the mRNA and protein levels of AFP and FOXa2, and increased the level of histone H3K27me3 in the AFP and FOXa2 gene promoter regions. In summary, the mouse histone methyltransferase EZH2 gene could suppress hepatocellular differentiation of mBMMSCs by increasing the level of H3K27me3 in the AFP and FOXa2 gene promoter regions.


Assuntos
Diferenciação Celular/genética , Hepatócitos/citologia , Hepatócitos/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Complexo Repressor Polycomb 2/genética , Animais , Proteína Potenciadora do Homólogo 2 de Zeste , Regulação da Expressão Gênica , Vetores Genéticos/genética , Fator 3-beta Nuclear de Hepatócito/genética , Histonas/metabolismo , Lentivirus/genética , Masculino , Camundongos , Complexo Repressor Polycomb 2/metabolismo , Regiões Promotoras Genéticas , Transdução Genética , alfa-Fetoproteínas/genética
12.
Eur Rev Med Pharmacol Sci ; 18(5): 680-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24668708

RESUMO

BACKGROUND AND OBJECTIVES: Our previous experiments showed that steep pulses could kill tumor cells, but the mechanism is unclear yet. This study was to probe the effects of different dosages of energy controllable steep pulses on intracellular concentration of dissociative calcium ion ([Ca2+]i) and cell membrane potential. MATERIALS AND METHODS: The mammary carcinoma cells MDA-MB-231 were divided into control group and 5 different dosages of Energy Controllable Steep Pulses (ECSP) treatment groups. The calcium ion in each group was labeled by Fluo-3/AM individually and the cell membrane potential was labeled by DiBAC4 (3). The mean fluorescence intensity of fluorescent probe in mammary carcinoma cells was observed in quiet state by laser confocal microscopy after ECSP treatment The changes of calcium concentration and cell membrane potential in cells after ECSP treatment were analyzed. The changes of intracellular [Ca2+]i after ECSP treatment were also observed with and without calcium ion outside of the cells. RESULTS: The calcium ion outside of cells influx with lower dosage of pulse in quiet state. With the dosage increase, the intracellular calcium ion outflow. In real time kinetic detection, the mean fluorescence intensity of intracellular calcium ion was increased with the pulse electric field intensity raised in the lower ECSP. When the voltage was 285V, frequency was 100Hz, the [Ca2+]i decreased. The increase of intracellular calcium ion concentration was decreased without calcium ion than with calcium ion outside of cells, but still raised gradually. The lower dosage of ECSP could induce the fluorescence intensity of DiBAC4 (3) in cells increase, which showed that the lower dosage of ECSP could induce the depolarization of cells. With the dosage raised, the fluorescence intensity of DiBAC4 (3) in cells attenuated. This dosage of ECSP could induce the superpolarization of cell membrane. CONCLUSIONS: The lower dosage of ECSP can induce the depolarization of cell membrane and induce the inter flow of calcium ion outside of cell membrane. The higher dosage of ECSP can directly destroy the cell membrane and induce the superpolarization of cell membrane, then induce the outflow of intracellular calcium ion which causes the necrosis of tumor cells.


Assuntos
Cálcio/metabolismo , Membrana Celular/metabolismo , Metabolismo Energético/fisiologia , Líquido Intracelular/metabolismo , Potenciais da Membrana/fisiologia , Linhagem Celular Tumoral , Campos Eletromagnéticos , Feminino , Humanos , Pulso Arterial
13.
Genet Mol Res ; 13(1): 415-24, 2014 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-24535868

RESUMO

Our research demonstrated the potential for mouse bone marrow mesenchymal stem cells (mBMMSCs) to differentiate into hepatocytes in vitro and in vivo. However, the exact mechanism of this process remains unknown. In this study, we investigated the role of the mitogen-activated protein kinase (MAPK) cell-signaling pathway in the differentiation of mBMMSCs into hepatocytes. mBMMSCs were isolated from femurs and tibias, and hepatic differentiation was induced in Isove's modified Eagle's medium supplemented with 10% fetal bovine serum, containing human growth factor and fibroblast growth factor 4. After seven days of induction, morphological characteristics were examined. For inhibition of signaling molecular activities, the inhibitors p38 (SB203580), ERK1/2 (U0126), and MSK1 (H89) were added to the differentiation medium. Real-time polymerase chain reaction and Western blot analysis were used to evaluate the gene expression profiles and protein expression of several markers, including the early specific markers of hepatocytes (AFP and FOXa2), phosphorylated-p38 (p-p38), phosphorylated-ERK1/2 (p-ERK1/2), and phosphorylated- MSK1 (p-MSK1). Expressions of p-p38, p-ERK1/2, and p-MSK1 were effectively inhibited by their respective inhibitors. Expressions of early specific markers, AFP and FOXa2, in the p38, ERK1/2, and MSK1 inhibitor-treated groups were significantly decreased compared to those of the cytokine-induced control. Notably, the expressions of AFP and FOXa2 in the p38 inhibitor group were more obviously reduced than those in the ERK1/2 inhibitor group. The MAPK signaling pathway, especially p38, is sufficient to drive differentiation of mBMMSCs into hepatocytes. This could increase the efficiency of hepatocyte differentiation, which would benefit clinical applications.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Fator 4 de Crescimento de Fibroblastos/farmacologia , Hepatócitos/citologia , Sistema de Sinalização das MAP Quinases , Células-Tronco Mesenquimais/citologia , Animais , Fator 3-beta Nuclear de Hepatócito/genética , Fator 3-beta Nuclear de Hepatócito/metabolismo , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Receptores de Peptídeos/genética , Receptores de Peptídeos/metabolismo , alfa-Fetoproteínas/genética , alfa-Fetoproteínas/metabolismo
14.
Climacteric ; 14(4): 472-81, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21469973

RESUMO

OBJECTIVES: Drospirenone is a novel progestogen that, combined with 17ß-estradiol, reduces the frequency and severity of menopausal vasomotor symptoms (VMS) in different populations. This double-blind, multicenter study compared the efficacy, safety and tolerability of 2 mg drospirenone/1 mg estradiol (DRSP/E2) vs. placebo in Chinese postmenopausal women with moderate to severe VMS. METHODS: Women, aged 45-65 years, were randomized to DRSP/E2 (n=183) or placebo (n=61) once daily for four 28-day cycles. Changes in the frequency and severity of hot flushes were analyzed as primary variables, together with other climacteric and urogenital symptoms, clinical global improvement, adverse events and physical/gynecological parameters. RESULTS: Relative changes in numbers of hot flushes/week were -80.4% for DRSP/E2 vs. -51.9% for placebo (treatment difference -28.5%, p<0.0001). There were trends toward a greater reduction in severity of hot flushes with DRSP/E2 treatment. Patients treated with DRSP/E2 were more often free from sweating episodes (p<0.0001) and vaginal dryness (p=0.0008). Other climacteric symptoms, including nervousness and pollakisuria, followed a trend of greater response with DRSP/E2. Similar to other combination HRT regimens, DRSP/E2 increased occurrences of bleeding, but these decreased over time. Adverse events in patients treated with DRSP/E2 were mostly mild to moderate and withdrawal rates were low. CONCLUSIONS: Daily treatment of postmenopausal Chinese women with DRSP/E2 for 16 weeks significantly reduced the incidence of hot flushes and demonstrated advantages vs. placebo for other climacteric symptoms. These results indicate that DRSP/E2 is effective, safe and well tolerated in postmenopausal Chinese women.


Assuntos
Androstenos/administração & dosagem , Estradiol/administração & dosagem , Terapia de Reposição de Estrogênios/métodos , Pós-Menopausa , Idoso , China , Método Duplo-Cego , Combinação de Medicamentos , Feminino , Fogachos/tratamento farmacológico , Humanos , Pessoa de Meia-Idade , Antagonistas de Receptores de Mineralocorticoides/administração & dosagem , Placebos , Doenças Vaginais/tratamento farmacológico
15.
Langmuir ; 25(11): 6076-80, 2009 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-19466773

RESUMO

Surface geometry affects strongly superhydrophobic behavior. To characterize the effect, roughness as a comprehensive geometrical parameter is used, but this parameter in its general mathematic expression cannot reflect exactly such a geometrical effect, in particular, for the regularly textured or ordered patterned superhydrophobic surfaces. In this study, we propose a new parameter to mathematically describe roughness for such superhydrophobic surfaces. On the basis of this parameter, an ideal surface texture with the maximum roughness for achieving the superhydrophobicity is suggested, which is consistent with the previous experimental observations and theoretical considerations.


Assuntos
Algoritmos , Interações Hidrofóbicas e Hidrofílicas , Propriedades de Superfície
16.
Cytotherapy ; 10(7): 668-75, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18985473

RESUMO

BACKGROUND: Although different strategies have been established for hepatic differentiation of mesenchymal stromal cells (MSC), further studies are required to define an efficient strategy to produce hepatocytes from stem cells and uncover the mechanisms of hepatic differentiation. METHODS: Bone marrow mesenchymal stromal cells (BMMSC), isolated from ICR mice, were induced by fetal liver-conditioned medium from different developmental stages, embryonic days (ED) 9.5, 11.5 and 13.5 and newborn (1 day). Differentiated cells were characterized by morphologic changes, liver-specific gene expression at mRNA and/or protein levels and in vitro functional features. RESULTS: BMMSC morphologically became epithelioid and binucleated after 7 days' exposure to fetal liver-conditioned medium from ED13.5, expressed liver-specific genes (AFP, HNF-3beta, TTR, CK18, ALB and CK19) at mRNA and/or protein levels and acquired in vitro functions characteristic of liver cells, including glycogen storage, urea production and albumin secretion. Conditioned medium derived from fetal liver at ED13.5 was most efficient on hepatic differentiation of BMMSC compared from the other three developmental stages. DISCUSSION: The present study not only provides a high-performance strategy for hepatic differentiation from BMMSC, but also implies liver at different developmental stages might secrete different types of cytokines that have diverse effects on hepatic differentiation, which could support further investigation to provide insight into fundamental processes that govern development and regeneration of the liver.


Assuntos
Técnicas de Cultura de Células , Transdiferenciação Celular , Meios de Cultivo Condicionados/farmacologia , Hepatócitos/citologia , Fígado/citologia , Células-Tronco Mesenquimais/citologia , Albuminas/biossíntese , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Feto , Expressão Gênica/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/embriologia , Masculino , Células-Tronco Mesenquimais/efeitos dos fármacos , Camundongos , Células Estromais/citologia , Células Estromais/efeitos dos fármacos
17.
Int J Gynecol Cancer ; 18(6): 1258-61, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18217966

RESUMO

Human ovarian cancer models were established in nude mice by transplanting SKOV(3) cells, and then tumors were exposed to high-intensity electric pulses with a voltage 1000 V, frequency of 1000 Hz, and duration of 250 ns for 1 min. Mitochondria permeability transition pore (PTP) was inspected by cofocal microscope; cytochrome C (Cyt C) and apoptosis-induced factor (AIF) were determined by immunohistochemistry; and voltage-dependent anion channel (VDAC) was measured by immunofluorescence. High-intensity electric pulses exposure led to increases of PTP, Cyt C, and AIF and a decrease of VDAC. These findings revealed that high-intensity electric pulses activated mitochondria electroporation, apoptosis was realized via mitochondria pathway.


Assuntos
Apoptose , Mitocôndrias/patologia , Neoplasias Ovarianas/patologia , Animais , Fator de Indução de Apoptose/metabolismo , Linhagem Celular Tumoral , Citocromos c/metabolismo , Eletroporação , Feminino , Humanos , Camundongos , Camundongos Nus , Mitocôndrias/metabolismo , Membranas Mitocondriais , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/terapia , Permeabilidade , Canais de Ânion Dependentes de Voltagem/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Cytotherapy ; 8(4): 381-9, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16923614

RESUMO

BACKGROUND: During the past few years multiple studies have revealed that adult stem cells, including BM origin stem cells, can be transdifferentiated into various cell types, including hepatocyte-like cells, under proper treatments or in a suitable microenvironment. However, little is known about the mechanism of the transdifferentiation, and the treatments employed seem to be very complicated and require simplification. It is important to determine the suitable conditions in which BM cells would be efficiently differentiated into hepatocytes. METHODS: Mouse BM cells were isolated from femurs and tibias and cultured in IMDM supplemented with 10% FBS. Hepatic differentiation was induced in a differentiation medium containing 20 ng/mL HGF, 10 ng/mL FGF-4, 10 ng/mL Oncostatin M (OSM) and different concentrations of liver-injured mouse sera. The differentiated hepatic cells were characterized by the expression of liver-associated mRNA and proteins and morphologic and functional features. RESULTS: BM cell-derived polygonal cell colonies appeared after several days of culture, and these hepatocyte-like cells expressed AFP, HNF-3beta, CK19, CK18, ALB, TAT and G-6-Pase at mRNA and protein levels, and the cells also had some hepatic cellular functions, such as glycogen storage and urea production. Interestingly, suitable concentrations of sera from liver-injured mice added to this system showed strong stimulation on the in vitro transdifferentiation of mouse BM cells into hepatocytes. DISCUSSION: In the present study we have established an effective hepatic differentiation system by a combination of HGF, FGF-4, OSM and liver-injured mouse sera in vitro. Accordingly, it will be a useful resource not only for understanding the mechanisms of transdifferentiation but also for efficient amplification of hepatocyte progenitor cells of BM origin.


Assuntos
Células da Medula Óssea/fisiologia , Diferenciação Celular/fisiologia , Hepatócitos/fisiologia , Animais , Células da Medula Óssea/citologia , Linhagem da Célula , Forma Celular , Células Cultivadas , Perfilação da Expressão Gênica , Glicogênio/metabolismo , Hepatócitos/citologia , Fígado/citologia , Fígado/patologia , Fígado/fisiologia , Masculino , Camundongos , Ureia/metabolismo
20.
J Environ Sci (China) ; 13(4): 472-5, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11723935

RESUMO

The decolorization of Direct Black 22 by Aspergillus ficuum has been studied. It was found that Aspergillus ficuum could effectively decolorize Direct Black 22 especially when grown as pelleted mycelia. Results showed that the media containing Direct Black 22 at 50 mg/L could be decolorized by 98.05% of the initial color in 24 h. The optimum pH and temperature of decolorization are 4.0 and 33 degrees C respectively. Aeration was quite beneficial to decolorization. Medium composition and the concentration of Direct Black 22 could affect the rate of decolorization. The dye degraded products assayed by UV-visible spectrophotometer and macroscopic observation showed that the decolorization of Direct Black 22 by mycelial pellets includes two important processes: bioadsorption and biodegradation. The degradation experiment agree with the Michaelis-Menten kinetics equation.


Assuntos
Aspergillus/fisiologia , Compostos Azo/metabolismo , Corantes/metabolismo , Naftalenos/metabolismo , Biodegradação Ambiental , Concentração de Íons de Hidrogênio , Cinética , Modelos Teóricos , Espectrofotometria Ultravioleta , Temperatura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...