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Biomedical subjects

M Y Wu

Publications and source records attributed to M Y Wu.

At least 19 recordsLinked to original sources

Nanobubbles in solid-state nanopores.

From conductance and noise studies, we infer that nanometer-sized gaseous bubbles (nanobubbles) are the dominant noise source in solid-state nanopores. We study the ionic conductance through solid-state nanopores as they are moved through the focus of an infrared laser beam. The resulting conductance profiles show strong variations in both the magnitude of the conductance and in the low-frequency noise when a single nanopore is measured multiple times. Differences up to 5 orders of magnitude are found in the current power spectral density. In addition, we measure an unexpected double-peak ionic conductance profile. A simple model of a cylindrical nanopore that contains a nanobubble explains the measured profile and accounts for the observed variations in the magnitude of the conductance.

Electric Conductivity↗

Arsenic trioxide reduces the invasive and metastatic properties of nasopharyngeal carcinoma cells in vitro.

Nasopharyngeal carcinoma (NPC) is notorious for the metastases, which are in close association with Epstein-Barr virus-encoded latent membrane protein 1 (LMP1). Arsenic trioxide (As2O3) has been shown to induce apoptosis and differentiation in NPC xenografts. Then, can it repress the cancer cells' metastasis potential? To elucidate this issue, the present study was performed. LMP1-negative cell line HNE1 and LMP1-positive cell line HNE1-LMP1 were used as in vitro model. Cells (1 x 10(5)/mL) were cultured with or without 3 microM As2O3 for 48 h. Then the survival cells were collected to investigate their potential of colony formation, attachment, invasion, and migration. Both confocal immunofluorescence staining and Western blot were used to detect the changes of LMP1 expression. The changes of MMP-9 were examined by RT-PCR assay and Western blot. The results were as follow: i) the colony formation inhibition rate (75.41 +/- 3.9% in HNE1-LMP1 cells vs 37.89 +/- 4.9% in HNE1 cells), the rate of attachment (HNE1-LMP1 vs HNE1: 56.40 +/- 3.5 vs 65.87 +/- 5.9%), the invasion inhibitory rate (HNE1-LMP1 vs HNE1: 56.50 +/- 3.7 and 27.91 +/- 2.1%), and the migration inhibitory rate (HNE1-LMP1 vs HNE1: 48.70 +/- 3.9 vs 29.19 +/- 6.27%) were all significantly different between the two cell lines (P < 0.01). ii) LMP1 was down-regulated in As2O3-treated HNE1-LMP1 cells. iii) The reduction of MMP-9 was found in As2O3-treated groups, more evident in HNE1-LMP1 cells. Thus, we conclude that As2O3 can reduce metastasis potential of NPC cells, involving inhibition of MMP-9 expression. LMP1 were also reduced in this process and seemed to enhance anti-metastasis activity of As2O3.

Antineoplastic Agents↗

High resolution EELS of Cu-V oxides: application to batteries materials.

Although widely used, the most promising Li-based technologies still need to seek new materials concepts to satisfy the increasing demands for energy storage worldwide. We report a layered electrode material, Cu(2.33)V4O11, for which the valency of copper, vanadium and thus indirectly the oxygen stoichiometry need to be investigated during the electrochemical cycle. High-resolution electron energy loss spectroscopy (HREELS) allows us to perform these measurements at the nanometer scale.

Journal Article↗

Identification of a tobacco protein interacting with tomato mosaic virus coat protein and facilitating long-distance movement of virus.

The protein-protein interaction of virus and host is essential for virus infection and host defense. The coat protein (CP) of tomato mosaic virus (ToMV) has been proved to be involved in cell-to-cell and long-distance movements of viruses that are presumably related with the protein-protein interactions. However, the host proteins that interact with the ToMV coat protein (ToCP) are largely unknown. In this study, we isolated a cDNA from a tobacco library through yeast two-hybrid system, which encodes a protein designated the ToMV CP-interacting protein-L (IP-L) that interacted with ToCP in vitro and in vivo. Sequencing analysis revealed that the putative coding region of IP-L gene was identical to that of an 'elicitor responsive protein' gene from N. tabacum (Genbank: #AB040409). A homology was also found between the cDNA sequence of IP-L and two senescence-related cDNAs (SENU1: Z75523 and AY479987) isolated from tomato and pepper. Northern blotting analysis showed that the mRNA level of IP-L was elevated after infection of ToMV. Then, we investigated the in vivo function of IP-L using virus-induced gene silencing (VIGS) and virus challenging assay. Semi-quantitative RT-PCR and Northern blotting results showed that the endogenous mRNA of IP-L in N. benthamiana plant was silenced at 10 days post inoculation with the in vitro transcripts of PVX-IP-L that were produced from the potato virus X (PVX)-based gene silencing plasmid pPC2S.IP-L. The IP-L silent plant developed a delayed systemic symptom at 7 days post challenging with ToMV, indicating that a high expression of IP-L was necessary for the interaction with ToCP to assist the viral transportation. Together, our data suggested that IP-L is a novel plant factor that interacts with the coat protein of ToMV and facilitates the long-distance movement of virus, which may provide a valuable clue for us to further investigate the mechanisms of plant virus infection and to control plant virus diseases.

Amino Acid Sequence↗

Progressive decrease of proinsulin secretion in sulphonylurea-treated type 2 diabetes.

Progressive deterioration of beta-cell function is proposed as a disease-related factor of sulphonylurea (SU) failure in type 2 diabetes. If it gradually worsens over time then disease duration may mirror the progressive beta-cell deterioration. The aim of the present study is to assess whether or not disease duration is influential in remodelling the secretion pattern of insulin-like molecules and in glucose control of SU-treated type 2 diabetes. A research model is used to investigate proinsulin secreting capacity over time, using two groups of patients: i) disease duration <5 years (n=62), comprising SU responders (SUr; n=48) and SU failures (SUf; n=14); and ii) disease duration > or = 5 years (n= 37), comprising an SUr group (n=17) and an SUf group (n=20). Blood samples are taken at 0 h, 0.5 h 1 h, 2 h and 3 h during a standard oral glucose tolerance test and measured for glucose, total proinsulin (TPI), intact proinsulin (IPI) and specific insulin (SI) concentrations. Pairwise comparison of estimated marginal means of blood glucose, SI, IPI and TPI levels at each time point are carried out between groups and subgroups. (SUr vs. SUf). Homa insulin resistance index (IR index) is applied to analyse IR between the groups. It was found that patients with shorter disease duration had higher proinsulin (TPI and IPI) levels at all time points (P<0.05), together with a lower glucose level at 2 h and 3 h (P<0.05). Homa insulin index analysis showed no difference between the two groups (P=0.26). Results also showed that the SUr group had a significantly lower glucose level at Oh and 3h (P<0.05), although no significant difference in insulin and proinsulin levels was found between the SUr and SUf groups. In conclusion, proinsulin may play an important role in glucose control in SU-treated type 2 diabetes, but the effect is reduced in SUf patients.

Adult↗

Latent membrane protein-1 of Epstein - Barr virus increases sensitivity to arsenic trioxide-induced apoptosis in nasopharyngeal carcinoma cell.

BACKGROUND AND AIM: Epstein - Barr virus (EBV)-encoded LMP1 is suggested to have an important role in the pathogenesis and development of nasopharyngeal carcinoma (NPC). Our previous study showed that As2O3 exhibited growth inhibition of NPC in animal model. Here, we further explore whether LMP1 is involved in As2O3 anticancer effects in NPC cell line. METHODS: Both the stable expressing LMP1 cell line HNE1-LMP1 and its parental cell line HNE1 without LMP1 expression were used as in vitro models to assess arsenic trioxide effect. Both cell lines were treated with As2O3 for 72 h. The median inhibition concentration (IC50) was assessed by the MTT assay. Apoptosis was observed by phase-contrast microscopy and TUNEL staining. The alteration of telomere lengths was detected by Southern blotting. RESULTS: IC50 for As2O3 in HNE1-LMP1 cells and HNE1 cells was 2.22 and 5.09 micromol/L, respectively. After exposure to 2 and 4 micromol/L As2O3 for 72 h, the apoptotic index in HNE1-LMP1 was 26.27 -/+ 1.3 and 49.13 -/+ 1.4%, respectively. On the contrary, in HNE1 cells the apoptotic index was 12.6 -/+ 0.9 and 33.20 -/+ 1.3%, respectively. As compared with parental cell line HNE1, HNE1-LMP1 cells were more sensitive to growth inhibition and apoptosis (p < 0.001). The elongation of telomere length was also found in HNE1-LMP1 cells. Meanwhile, longer telomeres in HNE1-LMP1 cells failed to maintain telomere stabilization, instead, it prone to be shortened when exposure to As2O3, as comparing with HNE1 cells. CONCLUSION: LMP1 plays important role in enhancing NPC cell response to As2O3. The elongation of telomere length induced by LMP1 may contribute to the mechanisms of As2O3 sensitivity.

Animals↗

Secondary sulphonylurea failure: what pathogenesis is responsible?

Sulphonylurea (SU) stimulates insulin secretion by pancreatic beta-cells and is generally used as a first-line treatment for type 2 diabetes. However, after long-term SU treatment (six months or over), some patients begin to show an increase in blood glucose once again (secondary SU failure). Two theories have been put forward to explain this failure--dysfunction of the proinsulin conversion machinery or insulin resistance. However, the primary pathogenesis behind secondary SU failure still needs to be investigated. Using a reliable technique that specifically identifies intact proinsulin (IPI), total proinsulin (TPI) and specific insulin (SI), this study aims to discover if a defect in the proinsulin converting mechanism plays a role in SU failure. Three groups were recruited for this study: healthy controls (n=8), SU responders (n=38) and secondary SU failures (n= 46). Serum concentrations of insulin-related molecules released in response to a standard glucose challenge test were compared between the groups. It was found that total SI was lower in the patient groups (P<0.05 compared to the control group), while TPI and IPI showed no distinct difference between the three groups (P>0.05). TPI:SI ratio and IPI:SI ratio showed marked increases in the patient groups (P<0.05 compared to control group), with no obvious quantitative difference between SU responders and secondary SU failures (P>0.05). Similar results for the Homa Insulin Resistant Index were found between the two patient groups. Interestingly, blood glucose at 180 mins after glucose challenge was significantly higher in the secondary SU failure group (P<0.05), with no correlation to SI, while the SU responder group showed good correlation between the parameters (P<0.05). We conclude that type 2 diabetes is associated with obvious dysfunction in the proinsulin-converting process and shows severe SI deficiency in responding to glucose challenge. Dysfunction of the proinsulin conversion mechanism was not an extra cause responsible for SU failure.

Adult↗

Dependence on initial conditions of an adsorption-desorption process.

A one-dimensional irreversible adsorption-desorption process is simulated. The critical parameters as well as the critical exponents are measured. At the critical point, the crossover between the accumulative state and the depleted state is described by a universal characteristic function.

Journal Article↗

Distribution of Th1 and Th2 cell populations in human peripheral and decidual T cells from normal and anembryonic pregnancies.

OBJECTIVE: To examine whether maternal immune responses during normal pregnancy are Th2 biased and whether there are specific changes when anembryonic pregnancy occurs. DESIGN: Prospective study. SETTING: Department of Obstetrics and Gynecology at a university hospital. PATIENT(S): We studied 32 pregnant women receiving elective abortions of normal pregnancies and 35 women with anembryonic pregnancies between 6 weeks and 10 weeks of gestational age. INTERVENTION(S): Using the multilabeling capability of three-color flow cytometry, it is possible to measure intracellular cytokines and cell surface markers simultaneously to determine which cells are the cytokine-producing cells. MAIN OUTCOME MEASURE(S): We examined the extent and proportion of mononuclear cells expressing specific T-cell surface markers and cytokines, interferon gamma, and interleukin 4 in the peripheral blood and deciduae. Secreted cytokines in the supernatants after 24-hour culture were also compared. RESULT(S): During the unstimulated status, the proportion of IL-4-secreting cells significantly exceeded that of IFN-gamma-secreting cells in the peripheral blood and decidua in normal pregnancies and was significantly decreased when anembryonic pregnancies occurred. Consequently, the Th1/Th2 ratios were increased during anembryonic pregnancies. However, after 24-hour culture, only another Th2-type cytokine, IL-10, was markedly increased and exceeded IFN-gamma secretion in cultures from both the peripheral blood and decidua in normal pregnancies. CONCLUSION(S): The decidual T lymphocytes are Th2 predominant. When anembryonic pregnancy occurs, this Th2 predominance disappears.

Cytokines↗

Mouse embryo toxicity of IL-6 in peritoneal fluids from women with or without endometriosis.

BACKGROUND: To determine whether there is a factor (or factors) in the peritoneal fluid of endometriosis patients that impairs embryo growth and embryo implantation. METHODS: Growth and development of two-cell mouse embryos which were cultured in media with peritoneal fluid from women with or without endometriosis and interleukin-1-beta (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) levels in conditioned media were measured. RESULTS: The blastocyst rate in the non-endometriosis group was 46.4 +/- 31.1%, and that of the endometriosis group was 54.6 +/- 28.7%. Logistic regression analysis using the criteria of blastocyst development in 454 embryos, showed that the peritoneal fluid from endometriosis could promote (p=0.015) but IL-6 could arrest embryo growth to blastocyst (p=0.025). IL-1beta and TNF-alpha levels had no significant effect on blastocyst formation. CONCLUSION: Peritoneal fluid from women with endometriosis was not toxic to mouse embryo development. However, IL-6 in the peritoneal fluid deteriorated the growth and development of mouse embryos.

Adult↗

Increase in the production of interleukin-10 early after implantation is related to the success of pregnancy.

PROBLEM: To study the correlation of interleukin (IL)-10, IL-11 leukemia inhibitory factor (LIF), placental growth factor (PIGF), and transforming growth factor (TGF)-beta and outcome of human pregnancy. METHOD OF STUDY: We prospectively measured the serum levels of these cytokines in patients undergoing in vitro fertilization (IVF) programs. A total of 60 women (non-pregnant, n = 27; early abortions, n = 12; normal pregnancies, n = 21) were enrolled. RESULTS: There was no difference in the cytokines studied on D0 and D14 among the three groups of women. The increase in PIGF from D0 to D14 after human chorionic gonadotropin (hCG) injection was greater in pregnant women than in non-pregnant women; however, the difference did not reach significance (P = 0.068). The increase in IL-10 production from D14 to D21 was significant in women with successful pregnancies compared to women in the abortion group. CONCLUSIONS: This increase in IL-10 may be important in sustaining a normal pregnancy early after implantation.

Embryo Implantation↗

The SNRPN promoter is not required for genomic imprinting of the Prader-Willi/Angelman domain in mice.

In mice and humans, the locus encoding the gene for small nuclear ribonucleoprotein N (SNRPN/Snrpn), as well as other loci in the region are subject to genomic imprinting. The SNRPN promoter is embedded in a maternally methylated CpG island, is expressed only from the paternal chromosome and lies within an imprinting center that is required for switching to and/or maintenance of the paternal epigenotype. We show here that a 0.9-kb deletion of exon 1 of mouse Snrpn did not disrupt imprinting or elicit any obvious phenotype, although it did allow the detection of previously unknown upstream exons. In contrast, a larger, overlapping 4.8-kb deletion caused a partial or mosaic imprinting defect and perinatal lethality when paternally inherited.

Angelman Syndrome↗

Experimental and clinicopathologic study on the relationship between transcription factor Egr-1 and esophageal carcinoma.

AIM: To observe the growth suppression effect of exogenous introduction of early growth response gene-1 (Egr-1 gene) on esophageal carcinoma tissue as well as on esophageal carcinoma cell line Eca109 and to explore the potential application of Egr-1 gene in gene therapy of tumor. METHODS: Eukaryotic expression vector of PCMV-Egr-1 plasmid was introduced into Eca109 cell line which expressed no Egr-1 protein originally with lipofectamine transfection method. The introduction and expression of PCMV-Egr-1 plasmid into Eca109 cell line was confirmed by G418 selection culture, PCR amplification of neogene contained in the vector, Western blot analysis and immunocytochemical analysis. The cell growth curve, soft agar colony formation rate and tumorigenicity in SCID mice were examined to demonstrate the growth suppression effect of exogenous Egr-1 gene on Eca109 cell line. The Egr-1 mRNA and Egr-1 protein were also detected in 50 surgical specimens of esophageal carcinoma by in situ hybridization and immunohistochemistry. RESULTS: Exogenous Egr-1 gene was introduced successfully into Eca109 cell line and expressed Egr-1 protein stably. The transfected Eca109 cell line grew more slowly than control Eca109 as shown by cell growth curves, the soft agar colony formation rate (4.0% vs 6.9%, P < 0.01) and the average growth rate of tumor in SCID mice (35.5 +/- 7.6 vs 65.8 +/- 7.6, P < 0.05). The expression level of Egr-1 mRNA and protein significantly increased in dysplastic epithelia adjacent to cancer rather than in cancer tissues (65.8% vs 20.0% by ISH and 57.9% vs 0.01). CONCLUSION: Exogenous Egr-1 gene shows the strong effect of growth inhibition in Eca109 cell line. Egr-1 in the cancer tissue shows down-regulated expression that supports the inhibited function of Egr-1 in cancer growth and suggests Egr-1 may have an important role in gene therapy of esophageal carcinoma.

Animals↗

Effectiveness of postoperative adjuvant therapy in improving reproductive outcome of endometriosis-associated infertility.

BACKGROUND AND PURPOSE: Treatment of endometriosis-associated infertility has not yet become standardized. Various protocols including surgical treatment, medical therapy, and a combination of both have been suggested but their use remains controversial. The objective of the present study was to determine whether postoperative adjuvant therapy for endometriosis is effective in improving reproductive outcome. METHODS: Medical records of infertile patients with newly diagnosed endometriosis treated in a university teaching hospital during a 50-month period were reviewed. After exclusion of patients with other major infertility factors, a total of 209 patients were included in the retrospective analysis. These patients were divided into those receiving (n = 78) or not receiving (n = 131) peri- or postoperative adjuvant medical therapy. The adjuvant therapies included danazol (n = 62), gonadotropin releasing hormone analogues (n = 11), progestins (n = 3), oral contraceptives (n = 1), and mixed treatment (n = 1). RESULTS: The pregnancy rate was lower in those receiving adjuvant therapy, although this result was not significant (32.1% vs 45.8%; p = 0.05). When patients using postoperative danazol therapy were considered alone, the pregnancy rate in patients receiving adjuvant therapy was significantly lower than that in patients not receiving it (p = 0.047). When the stage of endometriosis was considered, the pregnancy rate in patients receiving adjuvant therapy was again lower than in those not receiving it in patients with minimal or mild endometriosis (42.9% vs 60%; p = 0.043). However, in patients with moderate or severe endometriosis, the pregnancy rate was not different in the two groups (31% vs 36%; p = 0.56). Postoperative assisted reproductive techniques (ART) including controlled ovarian hyperstimulation/intrauterine insemination (COH/IUI) and in vitro fertilization (IVF) were effective in improving the pregnancy rates for all patients (53.9% with ART vs 33.1% without; p = 0.003) and for patients with advanced endometriosis (47.7% with ART vs 27.2% without; p = 0.016). CONCLUSIONS: Our results suggest that postoperative adjuvant therapy is ineffective in improving reproductive outcome in patients with either early (minimal or mild) or advanced (moderate and severe) endometriosis. This finding suggests that if fertility is the goal of treatment, adjuvant therapy may be unnecessary after surgery. In contrast, our data suggest that empirical ART, including COH/IUI or IVF, may be a better alternative to improve the pregnancy outcome after surgery.

Adult↗

[A study on pathological changes of closed diffuse brain injury in rats with H.E., esterification-silver stain and albumin immunohistochemical stain].

OBJECTIVE: To observed the pathological changes of closed diffuse brain injury in the rats died immediately and 15 min to 5 days after the injury. METHODS: H.E. staind and esterification-silver stain were applied to investigate the closed diffuse brain injury. RESULTS: In rats died immediately after the concussive injury, a number of shrunken neurons(type I change), distended neurons(type II change) and wave-like nerve fibers were identified in the brain tissue, especially in brain-stem. At 2 h and 8 h after injury, brain edema and axonal swelling appeared clearly in the cortex and white matter, especially in brain-stem. At post-traumatic 8 h and 24 h, the axonal retraction balls began to appear. The amount of neurons undergoing type I and II changes and constraction balls increased along with the survivor time. After 4 days and 5 days, brain edema alleviated, but the retraction balls and axonal swelling still existed. With Esterifica-tion silver stain, the above changes of neurons and nerve fibers were more obvious. With ABC stain, the distribution of albumin(Al) was extended from the perio-vascular area to diffuse distribution. Al positive staining were more obvious in injuried neurons and nerve fibers. CONCLUSION: The distribution of the concussive damage in the brain are coup, contra-coup and centripental.

Albumins↗

[Recent progress of study on single nucleotide polymorphisms].

Single nucleotide polymorphisms (SNPs) is a new genetic marker system following RFLP and microsatellite polymorphism. It has been shown to have the characteristics of high-density, inheritance stability and facilitation in analysis automation. SNPs can be detected by electrophoresis, endonuclease-cleavage, PCR and sequencing, and can be used extensively in gene mapping, disease-correlativity analysis, population genetics and drug research.

Chromosome Mapping↗

[A study of genetic polymorphism of the STR locus D2S441 in Chinese Han population in Chengdu].

Using PCR and PAG, followed by silver staining, the tetrameric STR D2S441 locus was studied in 260 unrelated Chinese individuals living in Chengdu. 9 alleles and 26 genotypes were observed. The range of fragment size was 131 bp to 155 bp. The genotype distribution of D2S441 locus in Han population was in accordance with Hardy-Weinberg equilibrium. Family survey confirmed Mendelian inheritance of alleles. The discriminating power (Dp), observed heterozygosity (H), polymorphism information content (PIC) and power of exclusion (PE) were 0.9084, 0.7885, 0.7390 and 0.5778 respectively. The results demonstrated that this locus was highly polymorphic and could be used for forensic identification and paternity testing.

Alleles↗