Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 120
Filtrar
1.
Nature ; 591(7851): 620-626, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33731924

RESUMO

Limited access to embryos has hampered the study of human embryogenesis and disorders that occur during early pregnancy. Human pluripotent stem cells provide an alternative means to study human development in a dish1-7. Recent advances in partial embryo models derived from human pluripotent stem cells have enabled human development to be examined at early post-implantation stages8-14. However, models of the pre-implantation human blastocyst are lacking. Starting from naive human pluripotent stem cells, here we developed an effective three-dimensional culture strategy with successive lineage differentiation and self-organization to generate blastocyst-like structures in vitro. These structures-which we term 'human blastoids'-resemble human blastocysts in terms of their morphology, size, cell number, and composition and allocation of different cell lineages. Single-cell RNA-sequencing analyses also reveal the transcriptomic similarity of blastoids to blastocysts. Human blastoids are amenable to embryonic and extra-embryonic stem cell derivation and can further develop into peri-implantation embryo-like structures in vitro. Using chemical perturbations, we show that specific isozymes of protein kinase C have a critical function in the formation of the blastoid cavity. Human blastoids provide a readily accessible, scalable, versatile and perturbable alternative to blastocysts for studying early human development, understanding early pregnancy loss and gaining insights into early developmental defects.


Assuntos
Blastocisto/citologia , Blastocisto/metabolismo , Diferenciação Celular , Células-Tronco Pluripotentes/citologia , Blastocisto/enzimologia , Técnicas de Cultura de Células/métodos , Linhagem Celular , Linhagem da Célula , Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/enzimologia , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Isoenzimas/metabolismo , Células-Tronco Pluripotentes/enzimologia , Células-Tronco Pluripotentes/metabolismo , Proteína Quinase C/metabolismo , Análise de Célula Única , Transcriptoma
2.
Apoptosis ; 2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38615083

RESUMO

MARCH5 is a ring-finger E3 ubiquitin ligase located in the outer membrane of mitochondria. A previous study has reported that MARCH5 was up-regulated and contributed to the migration and invasion of OC cells by serving as a competing endogenous RNA. However, as a mitochondrial localized E3 ubiquitin ligase, the function of MARCH5 in mitochondrial-associated metabolism reprogramming in human cancers remains largely unexplored, including OC. We first assessed the glycolysis effect of MARCH5 in OC both in vitro and in vivo. Then we analyzed the effect of MARCH5 knockdown or overexpression on respiratory activity by evaluating oxygen consumption rate, activities of OXPHOS complexes and production of ATP in OC cells with MARCH5. Co-immunoprecipitation, western-blot, and in vitro and vivo experiments were performed to investigate the molecular mechanisms underlying MARCH5-enhanced aerobic glycolysis s in OC. In this study, we demonstrate that the abnormal upregulation of MARCH5 is accompanied by significantly increased aerobic glycolysis in OC. Mechanistically, MARCH5 promotes aerobic glycolysis via ubiquitinating and degrading mitochondrial pyruvate carrier 1 (MPC1), which mediates the transport of cytosolic pyruvate into mitochondria by localizing on mitochondria outer membrane. In line with this, MPC1 expression is significantly decreased and its downregulation is closely correlated with unfavorable survival. Furthermore, in vitro and in vivo assays revealed that MARCH5 upregulation-enhanced aerobic glycolysis played a critical role in the proliferation and metastasis of OC cells. Taken together, we identify a MARCH5-regulated aerobic glycolysis mechanism by degradation of MPC1, and provide a rationale for therapeutic targeting of aerobic glycolysis via MARCH5-MPC1 axis inhibition.

3.
Reprod Biomed Online ; 49(3): 103993, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38901380

RESUMO

RESEARCH QUESTION: Is acrosin activity related to cumulative live birth rate (CLBR) over 1 year after IVF, intracytoplasmic sperm injection (ICSI) treatment or both? DESIGN: Retrospective monocentric cohort study of 5704 couples who started IVF/ICSI treatments between 2016 and 2021. Acrosin activity was determined by a modified Kennedy method using a commercial kit. Patients were divided into two groups according to their acrosin activity: below 25 µIU/106 spermatozoa; and an acrosin activity 25 µIU/106 spermatozoa or above. Primary outcome was the CLBR, defined as an ongoing pregnancy leading to live birth that had arisen from all embryo transfers carried out within 1 year after the first ovum retrieval. Both conservative and optimistic methods were used for estimating CLBRs. RESULTS: The CLBRs of patients with an acrosin activity below 25 µIU/106 spermatozoa were found to be significantly lower than those of patients with an acrosin activity 25 µIU/106 spermatozoa or above by conservative (48.5% versus 55.4%, P = 0.02) and optimistic (63.7% versus 70.3%, P = 0.047) methods after adjusting for confounders. When acrosin activity was regarded as a continuous variable, significant negative relationships between acrosin activity and CLBR were identified in subgroups: young couples (men and women aged younger than 30 years) and couples from whom no more than 10 eggs were retrieved. CONCLUSION: Low acrosin activity levels were correlated with decreasing CLBRs over 1 year. These findings suggest that acrosin activity can be used as a predictor for CLBRs before starting IVF/ICSI treatment to enhance the effectiveness of counselling.

4.
Mol Cell Biochem ; 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37882986

RESUMO

Cancer stem cells (CSCs) are a class of cells with self-renewal and multi-directional differentiation potential, which are present in most tumors, particularly in aggressive tumors, and perform a pivotal role in recurrence and metastasis and are expected to be one of the important targets for tumor therapy. Studies of tumor metabolism in recent years have found that the metabolic characteristics of CSCs are distinct from those of differentiated tumor cells, which are unique to CSCs and contribute to the maintenance of the stemness characteristics of CSCs. Moreover, these altered metabolic profiles can drive the transformation between CSCs and non-CSCs, implying that these metabolic alterations are important markers for CSCs to play their biological roles. The identification of metabolic changes in CSCs and their metabolic plasticity mechanisms may provide some new opportunities for tumor therapy. In this paper, we review the metabolism-related mechanisms of CSCs in order to provide a theoretical basis for their potential application in tumor therapy.

5.
J Med Internet Res ; 25: e42175, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37368468

RESUMO

BACKGROUND: Clinical research associates (CRAs) monitor the progress of a trial, verify the data collected, and ensure that the trial is carried out and reported in accordance with the trial protocol, standard operating procedures, and relevant laws and regulations. In response to monitoring challenges during the COVID-19 pandemic, Peking University Cancer Hospital launched a remote monitoring system and established a monitoring model, combining on-site and remote monitoring of clinical trials. Considering the increasing digitization of clinical trials, it is important to determine the optimal monitoring model for the general benefit of centers conducting clinical trials worldwide. OBJECTIVE: We sought to summarize our practical experience of a hybrid model of remote and on-site monitoring of clinical trials and provide guidance for clinical trial monitoring management. METHODS: We evaluated 201 trials conducted by our hospital that used on-site monitoring alone or a hybrid monitoring model, of which 91 trials used on-site monitoring alone (arm A) and 110 used a hybrid model of remote and on-site monitoring (arm B). We reviewed trial monitoring reports from June 20, 2021, to June 20, 2022, and used a customized questionnaire to collect and compare the following information: monitoring cost of trials in the 2 models as a sum of the CRAs' transportation (eg, taxi fare and air fare), accommodation, and meal costs; differences in monitoring frequency; the number of monitored documents; and monitoring duration. RESULTS: From June 20, 2021, to June 20, 2022, a total of 320 CRAs representing 201 sponsors used the remote monitoring system for source data review and the verification of data from 3299 patients in 320 trials. Arm A trials were monitored 728 times and arm B trials were monitored 849 times. The hybrid model in arm B had 52.9% (449/849) remote visits and 48.1% (409/849) on-site visits. The number of patients' visits that could be reviewed in the hybrid monitoring model increased by 34% (4.70/13.80; P=.004) compared with that in the traditional model, whereas the duration of monitoring decreased by 13.8% (3.96/28.61; P=.03) and the total cost of monitoring decreased by 46.2% (CNY ¥188.74/408.80; P<.001). These differences were shown by nonparametric testing to be statistically significant (P<.05). CONCLUSIONS: The hybrid monitoring model can ensure timely detection of monitoring issues, improve monitoring efficiency, and reduce the cost of clinical trials and should therefore be applied more broadly in future clinical studies.


Assuntos
COVID-19 , Neoplasias , Humanos , COVID-19/prevenção & controle , Monitorização Fisiológica , Pandemias , Estudos Retrospectivos , Ensaios Clínicos como Assunto
6.
Ecotoxicol Environ Saf ; 253: 114691, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36868036

RESUMO

There is evidence that the triazine herbicide atrazine, which is used extensively, is present in both surface water and groundwater, and its interfering effect on immune systems, endocrine systems, and tumours has been reported by laboratory and epidemiological studies. This study explored how atrazine affected 4T1 breast cancer cell development in vitro and in vivo. The obtained results showed that after exposure to atrazine, the cell proliferation and tumour volume were significantly increased and the expression of MMP2, MMP7, and MMP9 was upregulated. The thymus and spleen indices, the CD4 + and CD3 + lymphocyte percentages which from the spleen and inguinal lymph nodes, and the CD4 + /CD8 + ratio were noticeably lower than they were in the control group. Importantly, tumour-infiltrating lymphocytes such as CD4 + , CD8 + , and NK cells were decreased while Treg cells were increased. Moreover, IL-4 was increased and IFN-γ and TNF-α were decreased in the serum and tumour microenvironment. These results suggested that atrazine can suppress systemic as well as local tumour immune function and upregulate MMPs to promote breast tumour development.


Assuntos
Atrazina , Neoplasias da Mama , Herbicidas , Humanos , Feminino , Atrazina/toxicidade , Neoplasias da Mama/induzido quimicamente , Linfócitos T Reguladores , Herbicidas/toxicidade , Imunidade , Microambiente Tumoral
7.
Arch Gynecol Obstet ; 307(6): 1991-1999, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37041370

RESUMO

PURPOSE: The purpose of this study is to assess the impact of different temperatures and incubation times on the clinical outcomes of FET cycles during the thawing procedure and to select a better thawing method to improve clinical outcomes. METHODS: This retrospective study included 1734 FET cycles from January 1, 2020, to January 30, 2022. Embryos vitrified using a KITAZATO Vitrification Kit were thawed at 37 °C in all steps (the case group, denoted the "all-37 °C" group) or at 37 °C and then at room temperature (RT; the control group, denoted the "37 °C-RT" group), according to the kit instructions. The groups were matched 1:1 to avoid confounding. RESULTS: After case-control matching, 366 all-37 °C cycles and 366 37 °C-RT cycles were included. The baseline characteristics were similar (all P > 0.05) between the two groups after matching. FET of the all-37 °C group yielded a higher clinical pregnancy rate (CPR; P = 0.009) and implantation rate (IR; P = 0.019) than FET of the 37 °C-RT group. For blastocyst transfers, the CPR (P = 0.019) and IR (P = 0.025) were significantly higher in the all-37 °C group than in the 37 °C-RT group. For D3-embryo transfers, the CPR and IR were non-significantly higher in the all-37 °C group than in the 37 °C-RT group (P > 0.05). CONCLUSIONS: Thawing vitrified embryos at 37 °C in all steps with shortening wash time can enhance CPR and IR in FET cycles. Well-designed prospective studies are warranted to further evaluate the efficacy and safety of the all-37 °C thawing method.


Assuntos
Criopreservação , Transferência Embrionária , Humanos , Gravidez , Feminino , Estudos Retrospectivos , Criopreservação/métodos , Transferência Embrionária/métodos , Taxa de Gravidez , Implantação do Embrião , Vitrificação , Blastocisto
8.
J Clin Monit Comput ; 37(2): 379-387, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36399217

RESUMO

The reliability of stroke volume variation (SVV) and pulse pressure variation (PPV) in predicting fluid responsiveness during laparoscopic surgery remains unclear. We conducted the present systematic review to summarize the current evidence. We reviewed studies that investigated the reliability of SVV and PPV in laparoscopic surgery. Seven studies were included in the final analysis. Two studies demonstrated that the area under the receiver operating characteristic curve (AUROC) for SVV was less than 0.8, and five studies reported that the AUROC was > 0.8. The pooled AUROC for SVV and PPV was more than 0.8 with high heterogeneities between the included studies. Most individual studies have suggested that SVV and PPV are sufficiently reliable for predicting fluid responsiveness during laparoscopic surgery. However, the limited number of patients, varied apparatus used to define fluid responsiveness, diverse definitions of fluid responsiveness, and different fluids used to perform fluid challenges in the included studies render firm conclusions about SVV's and PPV's reliability impossible.


Assuntos
Hidratação , Laparoscopia , Humanos , Pressão Sanguínea , Volume Sistólico , Reprodutibilidade dos Testes , Curva ROC , Hemodinâmica
9.
Reprod Biol Endocrinol ; 20(1): 60, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35361225

RESUMO

BACKGROUND: Density gradient centrifugation (DGC) and swim-up (SU) are the two most widely used sperm preparation methods for in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). However, existing comparisons of IVF/ICSI outcomes following these sperm preparation methods are insufficient and controversial. METHODS: This retrospective study included all first autologous IVF and ICSI cycles performed between March 1, 2016, and December 31, 2020 in a single university-based center. A total of 3608 cycles were matched between DGC and SU using propensity score (PS) matching for potential confounding factors at a ratio of 1:1. The primary outcome was the cumulative live birth rate (cLBR) per aspiration. RESULTS: PS matching provided 719 cycles after DGC and 719 cycles after SU. After adjusting for confounders, the recovery rate, progressive motility rate after sperm preparation, fertilization rate, good-quality embryo rate, and blastocyst formation rate were similar between the DGC and SU groups. The cLBR (odds ratio [OR] = 1.143, 95% confidence interval [CI]: 0.893-1.461) and LBR per transfer (OR = 1.082, 95% CI: 0.896-1.307) were also not significantly different between the groups. Furthermore, no significant differences were found in all of the laboratory and clinical outcomes following conventional IVF or ICSI cycles between the two groups. However, a significantly higher fertilization rate (ß = 0.074, 95% CI: 0.008-0.140) was observed when using poor-quality sperm in the DGC group than in the SU group. CONCLUSIONS: Sperm preparation using DGC and SU separately resulted in similar IVF/ICSI outcomes. Further studies are warranted to compare the effects of these methods on IVF/ICSI outcomes when using sperm from subgroups of different quality.


Assuntos
Coeficiente de Natalidade , Injeções de Esperma Intracitoplásmicas , Centrifugação com Gradiente de Concentração , Feminino , Fertilização in vitro , Humanos , Masculino , Gravidez , Taxa de Gravidez , Pontuação de Propensão , Estudos Retrospectivos , Espermatozoides
11.
BMC Anesthesiol ; 22(1): 158, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35610575

RESUMO

BACKGROUND AND OBJECTIVE: Inferior vena cava (IVC) examination has been reported as a noninvasive method for evaluating the hemodynamic state. We conducted this crossover pilot study to investigate the effects of the administration of water and high-carbohydrate-containing fluids on the hemodynamic status of volunteers through collapsibility index of IVC (IVCCI) measurement. METHODS: Twenty volunteers were randomly assigned to a water or high-carbohydrate group according to computer-generated random numbers in a 1:1 ratio. In the water group, volunteers received water (5 mL/kg), and in the high-carbohydrate group, patients received carbohydrate drinks (5 mL/kg). Respiratory variations in the IVC diameter, gastric volume, and blood pressure and heart rates in erect and supine positions were measured at admission (T1), 1 h (T2), 2 h (T3), 3 h (T4), and 4 h (T5). RESULTS: When considering participants with an IVCCI of more than 42%, there were no significant differences between the water and carbohydrate drink groups at each time point (all p > 0.05). At T2, more participants had an empty stomach in water group than in carbohydrate drink group (p < 0.001). At T3, 30% of the participants could not empty their stomachs in carbohydrate drink group. However, with regard to the number of volunteers with empty stomach at T3, there was no significant difference between water and carbohydrate drink group. Repeated measures data analysis demonstrated that IVCCI showed no significant differences over time (p = 0.063 for T1-T5). There were no differences between water and carbohydrate drinks (p = 0.867). CONCLUSION: Our results suggested that neither water nor carbohydrate drinking affected the hemodynamic status through IVCCI measurement over time, up to 4 h after drinking. Furthermore, carbohydrate drinking might delay gastric emptying at 1 h, but not 2 h after drinking, in comparison with water.


Assuntos
Hemodinâmica , Estômago , Carboidratos , Humanos , Projetos Piloto , Estudos Prospectivos , Ultrassonografia , Água
12.
Biochem Biophys Res Commun ; 557: 323-328, 2021 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-33895473

RESUMO

Sonic hedgehog acts as a key mitogen to drive cell proliferation and as a morphogen to direct cell differentiation during embryonic development and adult tissue maintenance by controlling the activities of its transcriptional effectors Glis. We previously reported that RNF220 controls the nuclear translocation and subcellular localization of Glis by promoting their K63-linked polyubiquitination, through which it fine tunes Shh/Gli gradients during ventral spinal cord patterning. RNF220 also epigenetically regulates Shh signaling by targeting epifactor EED in cerebellar development. Here, we continued to study the molecular events underlying RNF220-mediated Shh regulation in the cytoplasm. The results showed that HDAC6 is required for RNF220-induced Gli accumulation in the cytoskeletal fraction and inclusion in aggresomes. In the cytoplasm, Glis polyubiquitinated by RNF220 are prone to interact with p62 and destined for autophagy-mediated degradation. Additionally, we showed that RNF220 inhibits the processing of Gli2 and Gli3 both in vitro and in vivo. Collectively, our studies shed new light on Shh signaling regulation.


Assuntos
Citoplasma/metabolismo , Citoesqueleto/metabolismo , Proteínas Hedgehog/metabolismo , Desacetilase 6 de Histona/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação/genética , Proteína GLI1 em Dedos de Zinco/metabolismo , Animais , Autofagia/genética , Citoesqueleto/genética , Células HEK293 , Desacetilase 6 de Histona/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , RNA Interferente Pequeno , Transdução de Sinais/genética , Ubiquitina-Proteína Ligases/genética , Proteína GLI1 em Dedos de Zinco/genética
13.
Mol Hum Reprod ; 27(2)2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33337472

RESUMO

Polycystic ovary syndrome (PCOS) is the most common endocrinological pathology among women of reproductive age, whereas the pathogenesis is still not fully understood. Systemic and ovarian oxidative stress (OS) imbalance is a pivotal feature of PCOS. Humanin, a mitochondria-derived peptide, has been reported to function as an antioxidant in cardiomyocytes, pancreatic beta cells and other cells, but how this function is regulated remains unclear. In this study, we investigated whether humanin expression differs in the granulosa cells (GCs) of PCOS patients versus controls, and whether humanin alleviates OS in PCOS ovaries. Sixteen PCOS patients and 28 age- and BMI-matched controls undergoing IVF were recruited, and their serum, follicular fluid and GCs were collected for humanin analysis. Dehydroepiandrosterone-induced rat PCOS models, and vitamin K3-induced OS COV434 cell lines were applied to investigate the mechanism. Humanin expression was significantly down-regulated in the ovaries of PCOS patients relative to those of non-PCOS patients. Exogenous humanin supplementation significantly attenuated body weight gain, ovarian morphological abnormalities, endocrinological disorders and ovarian and systemic OS in PCOS rat models. Our study further demonstrated that this attenuation effect was involved in the modulation of the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor-erythroid 2-related factor 2 (Nrf2) signalling pathway. In summary, this study reported for the first time that decreased expression of humanin in the GCs was associated with oxidative imbalance in PCOS. Humanin alleviates OS in ovarian GCs of PCOS patients via modulation of the Keap1/Nrf2 signalling pathway.


Assuntos
Células da Granulosa/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Ovário/metabolismo , Estresse Oxidativo , Síndrome do Ovário Policístico/metabolismo , Adulto , Animais , Estudos de Casos e Controles , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Células da Granulosa/patologia , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Fator 2 Relacionado a NF-E2/genética , Ovário/patologia , Síndrome do Ovário Policístico/genética , Síndrome do Ovário Policístico/patologia , Ratos Sprague-Dawley , Transdução de Sinais , Adulto Jovem
14.
J Perianesth Nurs ; 36(4): 388-392, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33678495

RESUMO

PURPOSE: New evidence-based fasting guidelines have been published in recent years. However, while water and solid food fasting times before anesthesia are recommended to be 2 and 6 hours, respectively, these times are often longer in clinical practice. This study aimed to investigate the awareness and implementation of the fasting guideline recommendations among nurses and anesthesiologists, as well as evaluate the actual fasting durations in patients in a tertiary hospital. DESIGN: A cross-sectional study was used. METHODS: Questionnaires were designed to collect the knowledge of fasting time among registered anesthesiologists and nurses. Data on the instructed and actual fasting durations among patients scheduled for elective surgery were evaluated. FINDINGS: Approximately half of the nurses indicated that solid food fasting durations were shorter than 6 hours or longer than 8 hours, and two-thirds indicated that clear fluid fasting durations were shorter than 2 hours or longer than 4 hours. However, in clinical practice, nurse-instructed fasting durations were longer than what they knew was optimal. The anesthesiologists also prescribed longer fasting durations than the minimum fasting duration recommended. The actual fasting durations of the patients were significantly longer than the nurse-instructed fasting durations for solid food (13.41 ± 2.64 vs 9.87 ± 2.20 hours, P < .001) and clear fluids (10.27 ± 3.67 vs 8.98 ± 2.90 hours, P < .001). The nurse-instructed durations were significantly longer than the anesthesiologist-instructed durations according to the statements of patients (9.87 ± 2.20 vs 9.00 ± 2.00 hours for solid food, P < .001; 8.98 ± 2.90 vs 6.15 ± 3.25 hours for clear fluids, P < .001). CONCLUSIONS: Excessive fasting durations were observed among patients. Anesthesiologists and nurses must work together to ensure that updated fasting instructions are implemented in routine clinical practice.


Assuntos
Jejum , Cuidados Pré-Operatórios , Estudos Transversais , Procedimentos Cirúrgicos Eletivos , Humanos , Centros de Atenção Terciária
15.
Entropy (Basel) ; 23(4)2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33924044

RESUMO

The natural gas hydrate plugging problems in the mixed pipeline are becoming more and more serious. The hydrate plugging has gradually become an important problem to ensure the safety of pipeline operation. The deposition and heat transfer characteristics of natural gas hydrate particles in the spiral flow pipeline have been studied. The DPM model (discrete phase model) was used to simulate the motion of solid particles, which was used to simulate the complex spiral flow characteristics of hydrate in the pipeline with a long twisted band. The deposition and heat transfer characteristics of gas hydrate particles in the spiral flow pipeline were studied. The velocity distribution, pressure drop distribution, heat transfer characteristics, and particle settling characteristics in the pipeline were investigated. The numerical results showed that compared with the straight flow without a long twisted band, two obvious eddies are formed in the flow field with a long twisted band, and the velocities are maximum at the center of the vortices. Along the direction of the pipeline, the two vortices move toward the pipe wall from near the twisted band, which can effectively carry the hydrate particles deposited on the wall. With the same Reynolds number, the twisted rate was greater, the spiral strength was weaker, the tangential velocity was smaller, and the pressure drop was smaller. Therefore, the pressure loss can be reduced as much as possible with effect of the spiral flow. In a straight light flow, the Nusselt number is in a parabolic shape with the opening downwards. At the center of the pipe, the Nusselt number gradually decreased toward the pipe wall at the maximum, and at the near wall, the attenuation gradient of the Nu number was large. For spiral flow, the curve presented by the Nusselt number was a trough at the center of the pipe and a peak at 1/2 of the pipe diameter. With the reduction of twist rate, the Nusselt number becomes larger. Therefore, the spiral flow can make the temperature distribution more even and prevent the large temperature difference, resulting in the mass formation of hydrate particles in the pipeline wall. Spiral flow has a good carrying effect. Under the same condition, the spiral flow carried hydrate particles at a distance about 3-4 times farther than that of the straight flow.

16.
Opt Express ; 28(22): 32907-32915, 2020 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-33114965

RESUMO

We propose the idea and design of a novel resonant micro-optical gyro based on a self-injection locking technique. By enhancing the reciprocity and measuring beat frequency, the sensitivity of gyro is improved effectively, which is usually limited by two main factors: low signal-to-noise ratio and immature signal detecting technique. In addition, a small size distributed feedback semiconductor laser with megahertz linewidth is used for miniaturization, instead of the narrow linewidth and tunable laser in traditional resonant gyros. Sensitivity of this resonant micro-optical gyro depends, in fact, on the accuracy of time measurement. In this paper, theory sensitivity is demonstrated to be at the order of 10-4 deg/h under a 6 KHz modulation frequency.

17.
BMC Gastroenterol ; 19(1): 173, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31690257

RESUMO

BACKGROUND: Molecular characteristics of CpG island methylator phenotype (CIMP) in colorectal cancer (CRC) have been well documented in Western, but not in Chinese, populations. METHODS: We investigated the incidence of CIMP, BRAF/KRAS mutation, and microsatellite instability (MSI) in a Chinese population with CRC (n = 401) and analysed associations between CIMP status and clinicopathological and molecular features. RESULTS: A total of 41 cases, 310 cases, and 40 cases were classified as CIMP-high, CIMP-low, and CIMP-negative, respectively. We detected a significantly low incidence of BRAF mutation in adenomas (2%) and CRC (0.7%), and a relatively low incidence of KRAS mutation (24.9%) compared with that in other populations. We also detected a relatively low incidence of CIMP-high (10.2%), which was significantly associated with younger age (≤49 years of age), female sex, and proximal tumour location. CONCLUSIONS: This study revealed unique characteristics of CIMP in a Chinese population with colorectal cancer. Developing specific CIMP markers based on unique populations or ethnic groups will further help to fully elucidate CIMP pathogenesis.


Assuntos
Povo Asiático/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Ilhas de CpG/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Metilação de DNA , Feminino , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Mutação , Fenótipo , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética
18.
Med Sci Monit ; 25: 4793-4800, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31250836

RESUMO

BACKGROUND The aim of this study was to explore the effect and mechanism of tanshinone II A on proliferation, apoptosis, and migration of human colon cancer cells. MATERIAL AND METHODS CCK-8 approach was carried out to evaluate proliferation after applying various levels of tanshinone II A to SW620 colon carcinoma cells. Flow cytometry (FC) was used to assess apoptosis. Transwell assay was performed to assess invasion in vitro, and the wound-healing assay was applied to assess migration. Western blot analysis was performed to evaluate translation of mTOR, while RT-PCR was carried out to assess transcription of VEGF. RESULTS CCK-8 assay showed that tanshinone II A inhibited SW620 proliferation in comparison to the control group subsequent to 24 h, 48 h, and 72 h (P<0.001). FC revealed that tanshinone II A promoted SW620 apoptosis (P<0.001). The cell migration test revealed that the migration index of cells receiving tanshinone II A decreased. mTOR translation as well as VEGE transcription in cells receiving tanshinone II A was noticeably prohibited compared to control group (P<0.001). CONCLUSIONS Tanshinone II A is able to inhibit proliferation and migration of human colon cancer SW620 cells and promoted cell death. Its mechanism may be by downregulation of mTOR protein and VEGF mRNA.


Assuntos
Abietanos/farmacologia , Neoplasias do Colo/metabolismo , Abietanos/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Humanos , Transdução de Sinais/efeitos dos fármacos
19.
Reprod Biol Endocrinol ; 16(1): 92, 2018 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-30249251

RESUMO

BACKGROUND: Evidence suggests that subclinical hypothyroidism (SCH) and thyroid autoimmunity (TAI) are associated with adverse pregnancy outcomes. This systematic review and meta-analysis was conducted to determine whether levothyroxine (LT4) supplementation would improve pregnancy outcomes among infertile women with SCH and/or TAI who underwent in vitro fertilization (IVF) or intracytoplastic sperm injection (ICSI). METHODS: We searched databases of PubMed, EMBASE, Web of Science, Cochrane Controlled Trials Register databases, and Clinicaltrials.gov up to April 2018 to identify eligible studies. Studies that focused on the treatment effect of LT4 on pregnancy outcomes of women with SCH and/or TAI who underwent IVF/ICSI were included in the data synthesis. We only included randomized controlled trials (RCTs). Relative risks (RR) and 95% confidence intervals (CI) were calculated using a random-effects model to assess the results of pregnancy outcomes, including clinical pregnancy rate, miscarriage rate, live birth rate and preterm birth rate. RESULTS: Four published RCTs including 787 infertile couples undergoing IVF/ICSI were included in this meta-analysis. Notably, the study observed no significant associations of LT4 treatment with the clinical pregnancy rate (RR = 1.46, 95% CI: 0.86-2.48), live birth rate (RR = 2.05, 95% CI: 0.96-4.36), or preterm birth rate (RR = 1.13, 95% CI: 0.65-1.96). However, patients receiving LT4 supplementation had a significantly decreased miscarriage rate relative to those receiving a placebo or no treatment (RR = 0.51, 95% CI: 0.32-0.82). A further sub-group analysis showed that LT4 supplementation did not improve the miscarriage rates among patients with SCH (RR = 0.67, 95% CI: 0.39-1.15) or TAI (RR = 0.28, 95% CI: 0.07-1.06). CONCLUSIONS: Given its potential to reduce the miscarriage rate, LT4 supplementation is recommended for infertile women with SCH and/or TAI who are undergoing IVF/ICSI. However, additional population-based RCTs are needed to confirm this recommendation.


Assuntos
Doenças Autoimunes/complicações , Hipotireoidismo/complicações , Infertilidade Feminina/tratamento farmacológico , Tiroxina/uso terapêutico , Doenças Autoimunes/tratamento farmacológico , Feminino , Humanos , Hipotireoidismo/tratamento farmacológico , Infertilidade Feminina/complicações , Gravidez , Resultado da Gravidez , Taxa de Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto , Injeções de Esperma Intracitoplásmicas
20.
J Cell Physiol ; 232(3): 625-634, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27333771

RESUMO

Epithelial-mesenchymal transition (EMT) is critical for induction of invasiveness and metastasis in HCC. Growing evidence indicates that upregulation of Snail, the major EMT inducer, significantly correlates with the metastasis and poor prognosis of HCC. Here, we investigate the underlying mechanism of miR-30b in suppressing metastasis of hepatoma cells by targeting Snail. In this study, we found that miR-30b was significantly downregulated and negatively associated with Snail production in HCC cell lines with higher metastatic potentials. Gain- and loss-of-function studies revealed that miR-30b could dramatically inhibit in vitro HCC cell migration and invasion. In vivo orthotopic liver xenograft model further demonstrated that stable over-expression of miR-30b significantly repressed the local invasion and lung metastasis of hepatoma cells. Meanwhile, the restoration of miR-30b expression suppressed the distant colonization of hepatoma cells. Both gain- and loss-of-function studies showed that miR-30b suppressed the EMT of hepatoma cells as indicated by the morphology changes and deregulation of epithelial and mesenchymal markers. Using RNAi, we further investigated the role of Snail in HCC cell EMT and demonstrated that knockdown of Snail significantly inhibited the EMT and cancer cell metastasis. Additionally, miR-30b exhibited inhibitory effects on HCC cell proliferation in vitro and in vivo. In conclusion, our findings highlight the significance of miR-30b downregulation in HCC tumor metastasis and invasiveness, and implicate a new potential therapeutic target for HCC metastasis. J. Cell. Physiol. 232: 625-634, 2017. © 2016 Wiley Periodicals, Inc.


Assuntos
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Transição Epitelial-Mesenquimal/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Neoplasias Pulmonares/secundário , MicroRNAs/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Pulmonares/patologia , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/genética , Invasividade Neoplásica , Fatores de Transcrição da Família Snail/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA