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Yu-li Wang

Publications and source records attributed to Yu-li Wang.

12 recordsLinked to original sources
PubMed2006

A multi-center study of hemodynamic characteristics exhibited by children with unexplained syncope.

BACKGROUND: Syncope is common in children and adolescents, with 15% estimated to have had at least one syncopal episode by age 18. In recent years, an increasing number of children, especially girls at their school age, have developed unexplained syncope. The mechanism of an unexplained syncope exhibited by children is incompletely studied; the association between different hemodynamic patterns and clinical features is also not clear. The aim of the study was to investigate the hemodynamic patterns of children with unexplained syncope and to examine the clinical relevance. METHODS: Two hundred and eight children [87 boys, 121 girls, aged 3 - 19 years, mean (11.66 +/- 2.72) years] were selectively recruited from May 2000 to April 2006 when they presented syncope as their main complaint at the Multi-center Network for Childhood Syncope in Beijing, Hunan Province, Hubei Province, and Shanghai of China. All of the patients underwent head-up tilt tests; data were analyzed using SPSS version 10.0 for Windows. Continuous variables were expressed as the mean +/- standard deviation. Dichotomous variables were compared through a chi(2) test. A value of P < 0.05 (two sided) was regarded as statistically significant. RESULTS: The age distribution of children with syncope was approximately normal. Head-up tilt tests was positive in 155 children, and the incidence of positive response of the baseline head-up tilt test for diagnosing unexplained syncope was 50.48%. The sensitivity value and diagnostic value of sublingual nitroglycerin head-up tilt test were both 74.52%. The hemodynamic pattern was normal in 53 children. The 155 children, who were positive in head-up tilt tests, showed signs of postural orthostatic tachycardia syndrome (60, 28.8%), the vasoinhibitory pattern (72, 34.6%), the cardioinhibitory pattern (5, 2.4%), and the mixed pattern (18, 8.7%). The gender distribution between the two age groups (age < 12 years vs age > or = 12 years) was not different (P > 0.05). The distribution of hemodynamic patterns between the children of the two age groups (age < 12 years vs age > or = 12 years), and the children with different complaints (dizziness vs syncope) was significantly different (P < 0.05), while the distribution between the children of different sexes and different lasting time of syncope (< or = 5 minutes vs > 5 minutes) was not significantly different (P > 0.05). Different hemodynamic patterns were differentiated by differing syncope inducements, presymptoms, and complicated symptoms during and after syncope. CONCLUSION: The tested girls were more prone when compared with the boys to have unexplained syncope, and the peak age was around twelve years old. The incidence of positive response of head-up tilt tests was also relatively higher for the girls. The distribution of hemodynamic patterns for different ages was different. For children with unexplained syncope, we should use head-up tilttests to distinguish the hemodynamic patterns in order to adopt rational therapeutic measures.

Adolescent↗
PubMed2006

From imaging to understanding: Frontiers in Live Cell Imaging, Bethesda, MD, April 19-21, 2006.

A recent meeting entitled Frontiers in Live Cell Imaging was attended by more than 400 cell biologists, physicists, chemists, mathematicians, and engineers. Unlike typical special topics meetings, which bring together investigators in a defined field primarily to review recent progress, the purpose of this meeting was to promote cross-disciplinary interactions by introducing emerging methods on the one hand and important biological applications on the other. The goal was to turn live cell imaging from a "technique" used in cell biology into a new exploratory science that combines a number of research fields.

Animals↗
PubMed2006

[A study on atrioventricular annular movement in healthy children by tissue Doppler imaging].

OBJECTIVE: Detecting the atrioventricular annular velocity along the long axis of ventricle by tissue Doppler imaging (TDI) is a useful modality to quantitatively assess global myocardial function. The present study was designed to quantitatively assess ventricular function in healthy children by TDI and to evaluate the clinical effect of growth and echocardiographic parameters on TDI velocities during childhood. METHODS: The study enrolled 242 healthy children aged 3 days to 17 years and they were divided into 8 groups: < 1 month of age group (37 cases), 1 month-of age group (28 cases), 7 months-of age group (21 cases), 1 year-of age group (36 cases), 4 years-of age group (40 cases), 7 years-of age group (26 cases), 10 years-of age group (28 cases) and > or = 13 years of age group (26 cases). Pulsed wave TDI velocities were obtained at the lateral mitral annulus (MA-L), basal septum (MA-S) and lateral tricuspid annulus (TA) during ventricular systole (Sa), early diastole (Ea) and late diastole (Aa), and Ea/Aa and E/Ea were obtained. Conventional echocardiography performed done and the parameters of left ventricular end-diastolic dimension (LVEDD), left ventricular ejection fraction (LVEF), the transmitral and transtricuspid flow E wave and A wave velocities and E/A ratio were obtained. TDI parameters were compared with demographic and echocardiographic variables. RESULTS: Sa, Ea and Ea/Aa were the lowest in children < 1 month of age [MA-L: Sa (4.8 +/- 0.7) cm/s, Ea (6.6 +/- 1.1) cm/s; MA-S: Sa (4.1 +/- 0.6) cm/s, Ea (5.0 +/- 0.8) cm/s; TA: Sa (6.2 +/- 1.2) cm/s, Ea (6.4 +/- 1.0) cm/s], and increased with age. The increase was significant from 1 month- to 1 year-of age group 1 year-of age group: MA-L: Sa (8.5 +/- 2.0) cm/s, Ea (16.3 +/- 2.6) cm/s; MA-S: Sa (7.2 +/- 0.8) cm/s, Ea (12.2 +/- 1.6) cm/s; TA: Sa (12.6 +/- 2.3) cm/s, Ea (14.7 +/- 2.6) cm/s. Ea and Sa of TA reached the older children's value earlier than those of the mitral annulus did. Aa increased in the 1 month-of age group compared to < 1 month of age group and remained stable beyond 1 year-of age group. Mitral annulus E/Ea ratio was high among neonates to 7-months-old children (MA-L: 9.2 +/- 2.1, MA-S: 12.1 +/- 2.9), and decreased with age, and there was a significant decrease in 1 year-of age group (MA-L: 5.9 +/- 1.2, MA-S: 7.8 +/- 1.3). In these healthy children, all the above TDI parameters except Aa were influenced by age, body surface area (BSA), LVEDD and heart rate. The influence of age and BSA showed a logarithm model. LVEDD was the main factor that influenced Sa and Ea of MA-L and MA-S, and it was the only single factor that influenced E/Ea ratio at mitral annulus. CONCLUSIONS: This study demonstrated that the left and right ventricular function developed with age in childhood, and it developed most rapidly during infancy and toddler period. The right ventricular function matured earlier than that of the left ventricle. Cardiac growth, age, and heart rate had important clinical effects on TDI velocities during childhood, and LVEDD had the most important influence on left ventricular systolic and diastolic function.

Adolescent↗
PubMed2005

Substrate rigidity regulates the formation and maintenance of tissues.

The ability of cells to form tissues represents one of the most fundamental issues in biology. However, it is unclear what triggers cells to adhere to one another in tissues and to migrate once a piece of tissue is planted on culture surfaces. Using substrates of identical chemical composition but different flexibility, we show that this process is controlled by substrate rigidity: on stiff substrates, cells migrate away from one another and spread on surfaces, whereas on soft substrates they merge to form tissue-like structures. Similar behavior was observed not only with fibroblastic and epithelial cell lines but also explants from neonatal rat hearts. Cell compaction on soft substrates involves a combination of weakened adhesions to the substrate and myosin II-dependent contractile forces that drive cells toward one another. Our results suggest that tissue formation and maintenance is regulated by differential mechanical signals between cell-cell and cell-substrate interactions, which in turn elicit differential contractile forces and adhesions to determine the preferred direction of cell migration and association.

3T3 Cells↗
PubMed2005

The mechanism of cortical ingression during early cytokinesis: thinking beyond the contractile ring hypothesis.

Owing to the rapid advances in genomic, proteomic and imaging technologies, the field of cytokinesis has seen rapid advances during the past decade. However, the basic model for the early stage of ingression, known as the contractile ring hypothesis, remains largely unchanged. From recent observations, it is becoming clear that early cytokinesis of animal cells involves a more extensive set of events, both temporally and spatially, than what is encompassed by the original contractile ring hypothesis. Activities relevant to cytokinesis, such as cortical contraction, can initiate well before onset of anaphase. Furthermore, equatorial ingression can involve multiple events in different regions of the cortex, including the establishment of anterior-posterior polarity, the modulation of cortical deformability, the expansion and compression of the cell cortex, and forces directed towards the interior of the cell or away from the equator. In this article (which is part of the Cytokinesis series), I evaluate critically key observations on when, where and how early ingression of animal cells takes place.

Actins↗
PubMed2005

[Up-regulation of costimulatory molecules by sodium butyrate in acute leukemia cells and its molecular mechanism].

OBJECTIVE: To explore the effect of sodium butyrate (SB) on the expression of costimulatory molecules in acute leukemia cells and its mechanism. METHODS: The expression of CD86 and CD80 was examined on the surfaces of NB4, HL-60, Kasumi-1, U937 and Jurkat cells by flow cytometric analysis after treated by SB or not. Allogeneic mixed lymphocyte reaction was used to evaluate the immunomodulatory effects of cells treated by SB. Activated NF-kappaB was measured with an NF-kappaB assay kit. RESULTS: Up-regulation of CD86 and CD80 at various levels was observed on these leukemia cells treated by SB. The ratio of CD86 expressing cell in NB4 cells treated by 0.5 mmol/L SB was 36.8 times higher than that in control. Up-regulation of NF-kappaB was similar to that of CD86. Allogeneic lymphocyte proliferation was strongly stimulated by the SB treated cells. CONCLUSION: SB can improve the expression of CD86 in acute leukemia cells. NF-kappaB was an important transcription factor involved in the up-regulation of CD86.

B7-1 Antigen↗
PubMed2004

Regulation of cell cycle by the anaphase spindle midzone.

BACKGROUND: A number of proteins accumulate in the spindle midzone and midbody of dividing animal cells. Besides proteins essential for cytokinesis, there are also components essential for interphase functions, suggesting that the spindle midzone and/or midbody may play a role in regulating the following cell cycle. RESULTS: We microsurgically severed NRK epithelial cells during anaphase or telophase, such that the spindle midzone/midbody was associated with only one of the daughter cells. Time-lapse recording of cells severed during early anaphase indicated that the cell with midzone underwent cytokinesis-like cortical contractions and progressed normally through the interphase, whereas the cell without midzone showed no cortical contraction and an arrest or substantial delay in the progression of interphase. Similar microsurgery during telophase showed a normal progression of interphase for both daughter cells with or without the midbody. Microsurgery of anaphase cells treated with cytochalasin D or nocodazole indicated that interphase progression was independent of cortical ingression but dependent on microtubules. CONCLUSIONS: We conclude that the mitotic spindle is involved in not only the separation of chromosomes but also the regulation of cell cycle. The process may involve activation of components in the spindle midzone that are required for the cell cycle, and/or degradation of components that are required for cytokinesis but may interfere with the cell cycle.

Anaphase↗
PubMed2004

Responses of fibroblasts to anchorage of dorsal extracellular matrix receptors.

Fibroblasts in 2D cultures differ dramatically in behavior from those in the 3D environment of a multicellular organism. However, the basis of this disparity is unknown. A key difference is the spatial arrangement of anchored extracellular matrix (ECM) receptors to the ventral surface in 2D cultures and throughout the entire surface in 3D cultures. Therefore, we asked whether changing the topography of ECM receptor anchorage alone could invoke a morphological response. By using polyacrylamide-based substrates to present anchored fibronectin or collagen on dorsal cell surfaces, we found that well spread fibroblasts in 2D cultures quickly changed into a bipolar or stellate morphology similar to fibroblasts in vivo. Cells in this environment lacked lamellipodia and large actin bundles and formed small focal adhesions only near focused sites of protrusion. These responses depend on substrate rigidity, calcium ion, and, likely, the calcium-dependent protease calpain. We suggest that fibroblasts respond to both spatial distribution and mechanical input of anchored ECM receptors. Changes in cell shape may in turn affect diverse cellular activities, including gene expression, growth, and differentiation, as shown in numerous previous studies.

Acrylic Resins↗
PubMed2002

The kinase activity of aurora B is required for kinetochore-microtubule interactions during mitosis.

As a component of the "chromosomal passenger protein complex," the aurora B kinase is associated with centromeres during prometaphase and with midzone microtubules during anaphase and is required for both mitosis and cytokinesis. Ablation of aurora B causes defects in both prometaphase chromosomal congression and the spindle checkpoint; however, the mechanisms underlying these defects are unclear. To address this question, we have examined chromosomal movement, spindle organization, and microtubule motor distribution in NRK cells transfected with a kinase-inactive, dominant-negative mutant of aurora B, aurora B(K-R). In cells overexpressing aurora B(K-R) fused with GFP, centromeres moved in a synchronized and predominantly unidirectional manner, as opposed to the independent, bidirectional movement in control cells expressing a similar level of wild-type aurora B-GFP. In addition, most kinetochores became physically separated from spindle microtubules, which appeared as a striking bundle between the spindle poles. These defects were associated with a microtubule-dependent depletion of motor proteins dynein and CENP-E from kinetochores. Our observations suggest that aurora B regulates the association of motor proteins with kinetochores during prometaphase. Interactions of kinetochore motors with microtubules may in turn regulate the organization of microtubules, the movement of prometaphase chromosomes, and the release of the spindle checkpoint.

Animals↗
PubMed2002

Fc-receptor-mediated phagocytosis is regulated by mechanical properties of the target.

Phagocytosis is an actin-based process used by macrophages to clear particles greater than 0.5 microm in diameter. In addition to its role in immunological responses, phagocytosis is also necessary for tissue remodeling and repair. To prevent catastrophic autoimmune reactions, phagocytosis must be tightly regulated. It is commonly assumed that the recognition/selection of phagocytic targets is based solely upon receptor-ligand binding. Here we report an important new criterion, that mechanical parameters of the target can dramatically affect the efficiency of phagocytosis. When presented with particles of identical chemical properties but different rigidity, macrophages showed a strong preference to engulf rigid objects. Furthermore, phagocytosis of soft particles can be stimulated with the microinjection of constitutively active Rac1 but not RhoA, and with lysophosphatidic acid, an agent known to activate the small GTP-binding proteins of the Rho family. These data suggest a Rac1-dependent mechanosensory mechanism for phagocytosis, which probably plays an important role in a number of physiological and pathological processes from embryonic development to autoimmune diseases.

Acrylic Resins↗