Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int J Mol Sci ; 23(23)2022 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-36499553

RESUMO

The liquid-liquid phase separation (LLPS) of proteins has been found ubiquitously in eukaryotic cells, and is critical in the control of many biological processes by forming a temporary condensed phase with different bimolecular components. TDP-43 is recruited to stress granules in cells and is the main component of TDP-43 granules and proteinaceous amyloid inclusions in patients with amyotrophic lateral sclerosis (ALS). TDP-43 low complexity domain (LCD) is able to de-mix in solution, forming the protein condensed droplets, and amyloid aggregates would form from the droplets after incubation. The molecular interactions regulating TDP-43 LCD LLPS were investigated at the protein fusion equilibrium stage, when the droplets stopped growing after incubation. We found the molecules in the droplet were still liquid-like, but with enhanced intermolecular helix-helix interactions. The protein would only start to aggregate after a lag time and aggregate slower than at the condition when the protein does not phase separately into the droplets, or the molecules have a reduced intermolecular helix-helix interaction. In the protein condensed droplets, a structural transition intermediate toward protein aggregation was discovered involving a decrease in the intermolecular helix-helix interaction and a reduction in the helicity. Our results therefore indicate that different intermolecular interactions drive LLPS and fibril formation. The discovery that TDP-43 LCD aggregation was faster through the pathway without the first protein phase separation supports that LLPS and the intermolecular helical interaction could help maintain the stability of TDP-43 LCD.


Assuntos
Esclerose Amiotrófica Lateral , Humanos , Amiloide , Proteínas Amiloidogênicas , Esclerose Amiotrófica Lateral/metabolismo , Agregados Proteicos
2.
J Am Chem Soc ; 143(29): 10940-10947, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34281341

RESUMO

Detailed information about the influences of the cooperative motion of water and methanol molecules on practical solid-liquid heterogeneous photocatalysis reactions is critical for our understanding of photocatalytic reactions. The present work addresses this issue by applying operando nuclear magnetic resonance (NMR) spectroscopy, in conjunction with density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, to investigate the dynamic behaviors of heterogeneous photocatalytic systems with different molar ratios of water to methanol on rutile-TiO2 photocatalyst. The results demonstrate that methanol and water molecules are involved in the cooperative motions, and the cooperation often takes the form of methanol-water clusters that govern the number of methanol molecules reaching to the active sites of the photocatalyst per unit time, as confirmed by the diffusion coefficients of the methanol molecule calculated in the binary methanol-water solutions. Nuclear Overhauser effect spectroscopy experiments reveal that the clusters are formed by the hydrogen bonding between the -OH groups of CH3OH and H2O. The formation of such methanol-water clusters is likely from an energetic standpoint in low-concentration methanol, which eventually determines the yields of methanol reforming products.

3.
Materials (Basel) ; 13(15)2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32751849

RESUMO

In the heat exchangers of sodium-cooled fast reactors, sodium flow can cause the tubes to vibrate, resulting in fretting wear damage due to the contact between the tubes (2.25Cr-1Mo steel) and their support plate (Gr5C12 alloy). In this work, the effects of temperature on the fretting wear behavior of a 2.25Cr-1Mo heat transfer tube on a Gr5C12 alloy rod were studied. The results showed that the coefficient of friction (COF) and wear volume increased first and then decreased with the increase in temperature. Moreover, 2.25Cr-1Mo showed great wear performance at high temperatures than at room temperature and 80 °C, because of the antifriction nature of the oxidative layer and the high hardness of the tribological transformed structure layer. As the temperature increased, material transfer and plastic deformation became increasingly obvious, but average wear depth decreased. This provides data support for the practical engineering application of 2.25Cr-1Mo steel at elevated temperatures. Wear mechanisms were found to depend modestly on temperature and largely on normal load. As temperature increases, the wear mechanism gradually changes from abrasive wear to adhesive wear.

4.
J Phys Chem Lett ; 11(9): 3738-3744, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32315184

RESUMO

Understanding the role of different solvent molecules for practical solid-liquid heterogeneous photocatalytic reactions is critical for determining the pathway of the reaction. In this study, the operando nuclear magnetic resonance (NMR) method, combined with density functional theory (DFT) calculations, was employed to evaluate the control effect of solvent water in the photocatalytic reforming mechanism of methanol with a Pt-TiO2 catalyst. Results indicate that the presence of water effectively promotes the formation of the HCHO intermediate but inhibits the H2 evolution originating from the switch of the hydrogen source of the H2 formation from CH3OH to H2O. More interestingly, as detected directly in the ab initio molecular dynamics simulation, a small amount of H2O can dissociate, and the evolved -OH species at Ti5c site can greatly reduce the C-H activation barrier of -CH3O, contributing to the formation of oxidation products (e.g., HOCH2OH and CH3OCH2OH) on the Pt-TiO2 surface.

5.
Mol Clin Oncol ; 7(2): 263-266, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28781799

RESUMO

HOXA distal transcript antisense RNA (HOTTIP), a critical oncogenic long non-coding RNA, has been reported to be aberrantly regulated in various cancer types. The present meta-analysis aimed to investigate HOTTIP as a potential clinical applicable prognostic biomarker in malignant neoplasms. Literature collections were performed by searching the electronic databases, PubMed and Web of Science (up to July 20, 2016). All the relevant searches were conducted to identify the association of HOTTIP with the overall survival (OS) rate. A total of six articles consisting of 508 patients were included in the present meta-analysis. The results suggested that the overexpression of HOTTIP is closely correlated with poor OS (hazard ratio=2.28; 95% confidence interval=1.71-3.04; P=0.000). In conclusion, the present meta-analysis has demonstrated that an increased expression level of HOTTIP is correlated with poor OS in different types of cancer, suggesting that HOTTIP potentially serves as a reliable prognostic biomarker in different types of cancer.

6.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 47(1): 60-3, 2016 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-27062783

RESUMO

OBJECTIVE: To determine the expression of miR-130a in patients with epithelial ovarian cancer and its association with platinum resistance. METHODS: 32 patients with platinum resistance and 30 patients without platinum resistance were recruited in this study. Real-time PCR was performed to detect the expression of miR-130a in the serum samples of the patients. ELISA was used to measure the expression level of phosphatase and tensin homolog deleted on chromosome ten (PTEN) and B-cell lymphoma-2 (BCL-2). RESULTS: Platinum-resistant patients had significantly higher levels of expression of miR-130a and BCL-2, and lower level of PTEN than platinum-sensitive patients (P < 0.05). The expression level of miR-130a increased with increased severity in histological classification and appearance of lymph node metastasis in the platinum-resistant patients (P < 0.05). CONCLUSION: MiR-130a may mediate the generation of platinum resistance in epithelial ovarian cancer through inhibiting PTEN to activate PI3K/AKT signaling pathway and increasing BCL-2 to inhibit tumor cell apoptosis. MiR-130a may be a new potential target of gene therapy in platinum-resistant ovarian cancers.


Assuntos
Resistencia a Medicamentos Antineoplásicos , MicroRNAs/sangue , Neoplasias Epiteliais e Glandulares/genética , Neoplasias Ovarianas/genética , Platina , Apoptose , Carcinoma Epitelial do Ovário , Feminino , Humanos , Neoplasias Epiteliais e Glandulares/sangue , Neoplasias Ovarianas/sangue , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo
7.
J Assist Reprod Genet ; 32(9): 1371-7, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26238389

RESUMO

PURPOSE: This study aimed to compare slow freezing (SF) and vitrification (VT) techniques for day 3 embryo cryopreservation in infertile couples. METHODS: This retrospective cohort study enrolled 5613 infertile patients, with 7862 frozen-thawed day 3 embryos and 3845 vitrified-warmed day 3 embryos, from 2010 to 2014, at a single center. The rates of embryo survival, pregnancy, implantation, miscarriage, live birth, and live birth weight were compared between the two groups. RESULTS: A total of 5613 cycles with 5520 transfers were analyzed. Using SF, the rates of overall embryo survival and fully intact blastomeres were lower than those in VT (91.5 vs. 97.4 % and 68.7 vs. 92.3 %, respectively). The rate of good quality embryos after thawing/warming was lower in SF than in VT. In single frozen embryo transfer cycles (FETs), the pregnancy and implantation rates were similar between the two groups (35.0 vs. 40.8 % and 34.6 vs. 35.9 %, respectively). In double FETs, the pregnancy rate per cycle was also similar between the groups (58.8 vs. 58.4 %). The implantation rate per embryo transfer was significantly higher with SF than with VT (38.8 vs. 34.6 %). With adjustment for maternal age and the number of good quality embryos, differences in implantation rate remained significant (adjusted P value, SF vs. VT P < 0.05). No independent effect was found for the method of cryopreservation on the pregnancy rate. No significant differences in the rates of miscarriage, live birth, and live birth weight were observed between the two techniques. CONCLUSIONS: Despite the significantly low embryo survival rate, fully intact blastomere rate, and good quality embryo rate in SF, the pregnancy and implantation rates were not adversely affected in single and double FETs. SF yielded an equivalent miscarriage rate, live birth rate, and live birth weight compared with VT. The SF protocol to cryopreserve day 3 embryos still should be considered.


Assuntos
Coeficiente de Natalidade , Criopreservação/métodos , Implantação do Embrião , Congelamento , Infertilidade , Vitrificação , Adulto , Blastômeros/citologia , Blastômeros/fisiologia , Transferência Embrionária , Feminino , Seguimentos , Humanos , Nascido Vivo , Gravidez , Taxa de Gravidez , Estudos Retrospectivos
8.
Chin Med J (Engl) ; 128(12): 1590-5, 2015 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-26063359

RESUMO

BACKGROUND: Generally, intracytoplasmic sperm injection (ICSI) may be the preferable method to treat partial globozoospermia, but whether there exist some correlations between ICSI fertilization rate and the proportion of round-headed sperm or morphologically normal sperm remains open. This study was to explore the correlation between ICSI fertilization rate and the sperm morphology in patients with partial globozoospermia. METHODS: Thirty-four patients diagnosed with partial globozoospermia accepted the following assisted fertilization treatments - 2 cases accepted in-vitro fertilization (IVF) alone, 26 cases accepted ICSI alone, and 6 accepted split IVF/ICSI. Detailed morphological characteristics were described using Diff-Quik rapid staining. Sixty cases accepting IVF or ICSI treatment in our reproductive center were considered as the control group after being matched by relevant criteria. Fertilization rate, embryo quality, embryo implantation rate and clinical pregnancy rate were calculated. RESULTS: Besides very high proportion of round-headed sperm, partial globozoospermia also showed very high proportion of small-acrosomal sperm and very low proportion of morphologically normal sperm. Fertilization rate of IVF (IVF alone plus split IVF) was very low in partial globozoospermia (25.4% ± 17.4%), but ICSI (ICSI alone plus split ICSI) achieved satisfying fertilization rate compared with the control group (66.2% ± 22.5% vs. 68.8% ± 29.4%, P > 0.05). In patients with partial globozoospermia, there were no correlations between ICSI fertilization rate and the proportion of round-headed sperm, small-acrosomal sperm, or morphologically normal sperm. CONCLUSIONS: There was high proportion of small-acrosomal sperm in partial globozoospermia. For patients with partial globozoospermia, ICSI is more preferable than IVF. ICSI fertilization rate does not depend on the proportion of round-headed sperm, small-acrosomal sperm, or morphologically normal sperm.


Assuntos
Infertilidade Masculina/terapia , Injeções de Esperma Intracitoplásmicas , Espermatozoides/citologia , Espermatozoides/fisiologia , Adulto , Feminino , Fertilização In Vitro , Humanos , Masculino , Gravidez , Espermatozoides/anormalidades
9.
Chemistry ; 21(17): 6346-9, 2015 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-25756618

RESUMO

Highly conductive, crystalline, polymer electrolytes, ß-cyclodextrin (ß-CD)-polyethylene oxide (PEO)/LiAsF6 and ß-CD-PEO/NaAsF6 , were prepared through supramolecular self-assembly of PEO, ß-CD, and LiAsF6 /NaAsF6 . The assembled ß-CDs form nanochannels in which the PEO/X(+) (X=Li, Na) complexes are confined. The nanochannels provide a pathway for directional motion of the alkali metal ions and, at the same time, separate the cations and the anions by size exclusion.

10.
Angew Chem Int Ed Engl ; 53(14): 3631-5, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24596167

RESUMO

A new category of crystalline polymer electrolyte prepared by the supramolecular self-assembly of polyethylene oxide (PEO), α-cyclodextrin (α-CD), and LiAsF6 is reported. The polymer electrolyte consists of the nanochannels formed by α-CDs in which the PEO/Li(+) complexes are confined. The nanochannels formed by α-CD provide the pathway for the directional motion of Li(+) ions and at the same time prevent the access of the anions by size exclusion, resulting in good separation of the Li(+) ions and the anions. The conductivity of the reported material is 30 times higher than that of the comparable PEO/Li(+) complex crystal at room temperature. By using state-of-art solid-state NMR spectroscopy, the structure and dynamics of the material were investigated in detail. The dynamics of the Li(+) ions was studied and correlated to the ionic conductivity of the material.

11.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 44(6): 865-70, 2013 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-24490491

RESUMO

OBJECTIVE: To determine the regulatory effects and associated mechanisms of miR-130a on cisplatin resistance in ovarian cancer A2780 cell lines (including cisplatin sensitive A2780s and its resistant A2780/DDP cells). METHODS: A2780s and A2780/DDP cells were divided into four groups, and treated with lipo2000 (Lip), miR-negative (miR-NC) control, miR-130a-mimics (miR-130a-M increasing the expression of miR-130a and the agent), and miR-130a-inhibitor (miR-130a-I downregulating miR-130a expression), respectively. The proliferation of cells and their sensitivity to cisplatin were detected by MTT assay. RT-PCR and western blot were performed to examine the levels of MDR1, PTEN mRNA and proteins. RESULTS: The expressions of MDR1 mRNA and P-gp in the A2780/DDP cells were significantly higher than those in the A2780s cells. However, no differences in the expressions of PTEN mRNA and proteins were detected between the two cell lines. Over-expressions of miR-130a had no effect on cell proliferation, but increased the resistance of the cells to cisplatin and up-regulated the expressions of MDR1 mRNA and P-gp in both cell lines. Down-regulated miR-130a did not affect cell proliferations, but enhanced the sensitivity of the cells to cisplatin, inhibited the expressions of MDR1 mRNA and P-gp and increased the expression of PTEN proteins. CONCLUSION: MiR-130a expression may be associated with cisplatin resistance of ovarian cancer cells. MiR-130a inhibitor can reverse the cisplatin resistance by upregulating the expression of PTEN proteins and down-regulating P-gp in A2780 cell lines. MiR-130 may become a new potential target of genetic therapy for cisplatin-resistant ovarian cancers.


Assuntos
Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , MicroRNAs/genética , Neoplasias Ovarianas/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Feminino , Humanos , MicroRNAs/antagonistas & inibidores , MicroRNAs/metabolismo , Neoplasias Ovarianas/patologia , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
12.
Chin Med J (Engl) ; 125(5): 863-8, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22490588

RESUMO

BACKGROUND: The regulation of endometrial physiology and morphogenesis by the paracrine effectors has been well established using in vivo studies. A more complete understanding of the endometrial function has been delayed due, in part, to a lack of appropriate culture models. In this study, we aimed to simulate the in vivo three-dimensional (3-D) growth pattern of endometrial cells using a 3-D in vitro culture system. METHODS: Isolated endometrial epithelial cells, stromal cells and RL95-2 cells were seeded into culture chambers coated with the extracellular matrix Matrigel and observed using light microscopy. Fluorescence staining and immunohistochemistry were used to assess the morphology. RESULTS: Depending on the culture conditions, epithelial cells and RL95-2 cells formed multicellular structures on Matrigel; stromal cells remained individually distinguishable or grew together to form 3-D lattice-like structures. CONCLUSIONS: Matrigel provided a good microenvironment for culturing endometrial cells. The cells cultured in the Matrigel-coated chambers closely resembled those seen in vivo.


Assuntos
Técnicas de Cultura de Células/métodos , Endométrio/citologia , Linhagem Celular , Células Cultivadas , Feminino , Humanos , Imuno-Histoquímica
13.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 43(1): 60-4, 2012 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-22455133

RESUMO

OBJECTIVE: To determine the expression of miR-130a in cisplatin resistant cell lines of ovarian cancer and its impact on cisplatin resistance. METHODS: Cisplatin resistant ovarian cancer cell lines were established by stepwise selection with gradual increase of cisplatin. MTT assay was applied to indentify the cisplatin resistant cell lines and determine their resistance index. The expression of miR-130a was measured by SYBR green real-time PCR. RESULTS: The resistance index of A2780/CIS1, A2780/CIS2 and SKOV3/CIS was 30.2, 5.3 and 24.5 respectively. The SYBR green real-time PCR showed that miR-130a was over-expressed in all of the cisplatin resistant cell lines (P < 0.05). The expression of miR-130a was 30.51 times higher in A2780/CIS1, 4.87 times higher in A2780/CIS2 and 24.43 times higher in SKOV3/CIS than in their parental cell lines (P < 0.05), which was almost equally reflected in their resistance index. CONCLUSION: The over expression of miR-130a is associated with cisplatin resistance of ovarian cancer. Inhibiting miR-130a expression may help reverse the cisplatin resistance of ovarian cancer. miR-130a is expected to be a new potential target of genetic therapy for cisplatin resistant ovarian cancer.


Assuntos
Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , MicroRNAs/metabolismo , Neoplasias Ovarianas/genética , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Feminino , Humanos , MicroRNAs/genética , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia
14.
Fa Yi Xue Za Zhi ; 27(6): 434-7, 2011 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-22393593

RESUMO

OBJECTIVE: To explore medico-legal characteristics of sudden death caused by coronary heart disease combined with coronary thrombosis. METHODS: Ninety-six cases of sudden death caused by coronary heart disease were collected and divided into two groups: thrombus positive and thrombus negative groups. The time onset, induction and pathological features of coronary artery disease were analyzed. RESULTS: Two groups showed man-dominant population. There were no statistical significant differences in season, circadian rhythm and induction factor. The thrombus positive group (age < 40) showed a higher disease incidence. Heart weight and degree of coronary stenosis were lower in thrombus positive group. However, there was no statistical difference in the number of atherosclerotic coronary arteries (> or = 2), the length of coronary lesions and myocardial infarct. But thrombosis positive group showed lower tendency. CONCLUSION: Two groups are man-dominant population and similar induction factor, lesion position, mechanism of death. But thrombus positive group appeared more in a younger population and the degree of coronary stenosis is milder than thrombus negative group. Forensic pathologists should pay more attention to these characteristics in death investigation.


Assuntos
Doença da Artéria Coronariana/complicações , Trombose Coronária/complicações , Vasos Coronários/patologia , Morte Súbita Cardíaca , Patologia Legal , Adulto , Fatores Etários , Idoso , Autopsia , Causas de Morte , Doença da Artéria Coronariana/epidemiologia , Doença da Artéria Coronariana/patologia , Trombose Coronária/epidemiologia , Trombose Coronária/patologia , Morte Súbita Cardíaca/epidemiologia , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/complicações , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/patologia , Miocárdio/patologia , Fatores de Risco
15.
Zhongguo Dang Dai Er Ke Za Zhi ; 12(12): 976-8, 2010 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-21172136

RESUMO

OBJECTIVE: To study the effects of vitamin A on the development of T lymphocytes in peripheral blood and small intestine and on the cytokine response of intestinal mucosa in mice. METHODS: Twenty young mice were randomly fed with forage containing vitamin A 250 or 4 IU/g (n=10 each). Three weeks later, the levels of CD4+ CD25+ T subsets in peripheral blood and intestinal mucosa were measured by flow cytometry. The levels of cytokines IFN-γ, IL-4, IL-17 and IL-23 in stool were measured using ELISA. RESULTS: The levels of CD4+ CD25+ T subsets in peripheral blood and intestinal mucosa in the 250 IU/g vitamin A group were significantly higher than those in the 4 IU/g vitamin A group (P<0.05). The IL-4 level in stool increased, in contrast, the IL-23 level in stool decreased significantly in the 250 IU/g vitamin A group when compared with the 4 IU/g vitamin A group (P<0.05). CONCLUSIONS: vitamin A may promote the development of CD4+ CD25+ T lymphocytes in peripheral blood and small intestine. Moreover, it may be involved in intestinal mucosa-associated immune response by regulating cytokines IL-4 and IL-23.


Assuntos
Citocinas , Vitamina A , Animais , Linfócitos T CD4-Positivos , Citometria de Fluxo , Interleucina-4 , Mucosa Intestinal , Camundongos , Linfócitos T Reguladores
16.
Int J Dermatol ; 47(5): 432-7, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18412857

RESUMO

We report a case of an 18-month-old boy with slightly whitened fingernails and toenails since birth. At the age of 100 days, he progressively developed bilateral palmoplantar keratoderma which resulted in painful walking and disabled grasping. Perianal keratotic plaques and perioral hyperkeratotic erythema could also be observed. Both fingernails and toenails were dystrophic. Scalp hairs were sparse, but total alopecia was no present. The histopathologic changes of the biopsy from the inner side of the right foot showed nonspecific changes, which mainly showed highly hyperkeratosis and acanthosis with slight superficial perivascular inflammatory infiltration. A clinical diagnosis of Olmsted syndrome was established according to the typical feature of the lesions, which is the presence of symmetrical palmoplantar keratoderma with periorificial keratotic plaques. We review the literature and present a summary of all reported cases to date.


Assuntos
Anormalidades Múltiplas/patologia , Ceratodermia Palmar e Plantar/patologia , Ceratose/patologia , Membrana Mucosa/patologia , Pele/patologia , Feminino , Doenças do Cabelo/patologia , Humanos , Lactente , Masculino , Doenças da Unha/patologia , Síndrome
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...