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Mei Yu

Publications and source records attributed to Mei Yu.

At least 19 recordsLinked to original sources
PubMed2026

Enhancer-promoter interaction maps in pig implantation tissue identify candidate cis-regulatory elements and regulatory variants.

Due to the polygenic nature of pig reproductive traits, most variants accounting for the phenotypic variation remain poorly characterized. It is well established that trait-associated variants are often enriched in regulatory elements of relevant tissues, and coordinated endometrial-conceptus crosstalk is critical for implantation success. Accordingly, this study aimed to investigate the chromatin landscape in pig endometrium-conceptus tissues and identify regulatory variants associated with reproductive traits. Combining RNA-seq and ChIP-seq, we uncovered cis-regulatory elements whose histone modification patterns correlate with gene expression. H3K27ac-based chromatin interaction profiling further resolved 2137 cis-regulatory elements involved in enhancer-promoter (E-P) interactions. Subsequent analyses identified candidate variants within these regulatory regions that associate with reproductive traits, in which the enhancer SNP rs346038249 likely affects transcriptional activity through allele-dependent transcription factor binding. Collectively, our findings provide mechanistic insights into pig embryo implantation and nominate candidate regulatory variants that merit further functional validation for their potential role in pig genetic improvement.

Embryo implantation↗
PubMed2006

Cocaine increases the intracellular calcium concentration in brain independently of its cerebrovascular effects.

Cocaine abuse increases the risk of life-threatening neurological complications such as strokes and seizures. Although the vasoconstricting properties of cocaine underlie its cerebrovascular effects, the mechanisms underlying its neurotoxicity remain incompletely understood. Here, we use optical techniques to measure cerebral blood volume, hemoglobin oxygenation (S(t)O(2)), and intracellular calcium ([Ca(2+)](i)) to test the hypothesis that cocaine increases [Ca(2+)](i) in the brain. The effects of cocaine were compared with those of methylphenidate, which has similar catecholaminergic effects as cocaine (except for serotonin increases) but no local anesthetic properties, and of lidocaine, which has similar local anesthetic effects as cocaine but is devoid of catecholaminergic actions. To control for the hemodynamic effects of cocaine, we assessed the effects of cocaine in animals in which normal blood pressure was maintained by infusion of phenylephrine, and we also measured the effects of transient hypotension (mimicking that induced by cocaine). We show that cocaine induced significant increases ( approximately 10-15%) in [Ca(2+)](i) that were independent of its hemodynamic effects and of the anesthetic used (isofluorance or alpha-chloralose). Lidocaine but not methylphenidate also induced significant [Ca(2+)](i) increases ( approximately 10-13%). This indicates that cocaine at a dose within the range used by drug users significantly increases the [Ca(2+)](i) in the brain and its local anesthetic, but neither its catecholaminergic nor its hemodynamic actions, underlies this effect. Cocaine-induced [Ca(2+)](i) increases are likely to accentuate the neurotoxic effects from cocaine-induced vasoconstriction and to facilitate the occurrence of seizures from the catecholaminergic effects of cocaine. These findings support the use of calcium channel blockers as a strategy to minimize the neurotoxic effects of cocaine.

Anesthetics, Local↗
PubMed2006

Autographa californica multiple nucleopolyhedrovirus nucleocapsid assembly is interrupted upon deletion of the 38K gene.

38K (ac98) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly conserved baculovirus gene whose function is unknown. To determine the role of 38K in the baculovirus life cycle, a 38K knockout bacmid containing the AcMNPV genome was generated through homologous recombination in Escherichia coli. Furthermore, a 38K repair bacmid was constructed by transposing the 38K open reading frame with its native promoter region into the polyhedrin locus of the 38K knockout bacmid. After transfection of these viruses into Spodoptera frugiperda cells, the 38K knockout bacmid led to a defect in production of infectious budded virus, while the 38K repair bacmid rescued this defect, allowing budded-virus titers to reach wild-type levels. Slot blot analysis indicated that 38K deletion did not affect the levels of viral DNA replication. Subsequent immunoelectron-microscopic analysis revealed that masses of electron-lucent tubular structures containing the capsid protein VP39 were present in cells transfected with 38K knockout bacmids, suggesting that nucleocapsid assembly was interrupted. In contrast, the production of normal nucleocapsids was restored when the 38K knockout bacmid was rescued with a copy of 38K. Recombinant virus that expresses 38K fused to green fluorescent protein as a visual marker was constructed to monitor protein transport and localization within the nucleus during infection. Fluorescence was first detected along the cytoplasmic periphery of the nucleus and subsequently localized to the center of the nucleus. These results demonstrate that 38K plays a role in nucleocapsid assembly and is essential for viral replication in the AcMNPV life cycle.

Animals↗
PubMed2006

An improved strategy for high-level production of TEV protease in Escherichia coli and its purification and characterization.

Because of its stringent sequence specificity, tobacco etch virus (TEV) protease emerges as a useful reagent with wide application in the cleavage of recombinant fusion proteins. However, the solubility of TEV protease expressed in Escherichia coli is extremely low. In the present study, we introduced a more efficient system to improve and facilitate the soluble production of TEV protease in E. coli. Optimal expression of soluble His6-TEV was achieved by examining the contribution of chaperone co-expression and lower temperature fermentation. When further purified by Ni(2+) affinity chromatography, 65mg of His6-TEV was isolated with purity over 95% from 1L of culture. The enzyme activity of His6-TEV was generally characterized by using GST-EGFP and His6-L-TNF fusion protein as substrates, which contained a TEV cleavage site between two moieties.

Chaperonin 10↗
PubMed2006

Alopecia areata: pathogenesis and potential for therapy.

Although the complete picture for alopecia areata (AA) pathogenesis has yet to be determined, recent research has made much progress in our understanding of the disease mechanism. Numerous circumstantial evidence supports the notion that AA is fundamentally a disease mediated by inflammatory cells and may be autoimmune in nature. Recent research has shown the hair-loss phenotype is precipitated predominantly by CD8+ lymphocytes, but the disease mechanism is driven by CD4+ lymphocytes. Although genetic susceptibility is a key contributor to disease development, disease onset and phenotypic presentation are probably modified by complex environmental interplay. On the basis of our current understanding of AA disease pathogenesis, several experimental and theoretical therapeutic approaches might be possible. However, the pathogenetic disease mechanism is particularly robust and the development of a cure for AA will be a significant challenge.

Alopecia Areata↗
PubMed2006

Genetic variations of 13 indigenous Chinese goat breeds based on cytochrome B gene sequences.

Phylogenetic relationships among and genetic variability within 13 Chinese indigenous goat breeds and Boer goat were analyzed using cytochrome b gene sequences. There were 44 variable sites found in a 642 bp sequence, and 46 Cyt b haplotypes were subsequently defined. The phylogeny analysis of haplotypes in combination with goat Cyt b sequences from GenBank shows that Chinese goats are obviously separated from wild goats and might come from Capra aegagrus. Further analysis indicated that indigenous Chinese goats might descend from at least two lineages; most of the individuals analyzed could be classified into lineage A as defined by Luikart, but five other goats were of uncertain lineage. The Tibet plateau is a possible place of origin for Chinese goats. The neighbor-joining tree based on pairwise differences among populations shows that most Tibetan goats, except the Middle Tibet type, cluster closely with North China goats, and then with South China goats. This result confirms that differences in genetic structure exist among goats in different geographic locations. Nucleotide diversity varied among populations. Tibet and North China goats had higher genetic diversity than South China goats. The fixation index (F (st)=87.72%) suggested that most of the total genetic variation was due to variation within populations. In addition, the results indicate that Cyt b gene sequence information alone might not be enough for phylogeny analysis among breeds within species, as shown by fewer polymorphic sites and lower bootstrap values on the neighbor-joining tree.

Animals↗
PubMed2006

Clinically relevant expansion of hematopoietic stem cells with conserved function in a single-use, closed-system bioprocess.

The clinical potential of umbilical cord blood-derived stem and progenitor cells has been demonstrated in various animal and human transplantation studies. However, the need for increased numbers of appropriate umbilical cord blood-derived cells continues to limit the development and success of these therapies. Ex vivo expansion has been widely studied as a method to overcome this limitation. We describe the use of a clinically relevant single-use, closed-system bioprocess capable of generating greater numbers of hematopoietic stem and progenitor cells that maintain in vivo and in vitro developmental potential. In addition to expanded numbers of CD34+ cells, CD34(+)CD38(-) cells, colony-forming cells, and long-term culture-initiating cells, the bioprocess generated > or =3.3-fold more long-term nonobese diabetic/severe combined immunodeficient repopulating cells (quantitatively determined using limiting dilution analysis) than present at input. Interestingly, these cells were also capable of multilineage engraftment and were shown to maintain their engraftment potency on a per long-term nonobese diabetic/severe combined immunodeficient repopulating cell basis compared with input noncultured cells. The developmental capacity of bioprocess-generated cells was further demonstrated by their ability to repopulate secondary nonobese diabetic/severe combined immunodeficient recipients. In vitro lineage analysis confirmed that bioprocess-generated cells could differentiate into myeloid and natural killer, B, and T cell lymphoid lineages. This in-depth analysis describes a bioprocess that generates human hematopoietic stem and progenitor cells with conserved hematopoietic activity, establishes analysis criteria for in vitro hematopoietic stem cell expansion studies, and serves as a foundation to test the therapeutic utility of cultured hematopoietic stem cells in large animals and humans.

Animals↗
PubMed2006

Differentially expression of Tua1, a tubulin-encoding gene, during flowering of tea plant Camellia sinensis (L.) O. Kuntze using cDNA amplified fragment length polymorphism technique.

The complementary DNA (cDNA) amplified fragment length polymorphism technique was used to isolate transcript-derived fragments corresponding to genes involved in the flowering of tea plant. Comparative sequence analysis of an approximately 300 bp differential fragment amplified by primer combination E11M11 revealed 80%-84% similarity to the corresponding part of an a-tubulin gene of other species. The complete cDNA sequence of this a-tubulin was cloned by the rapid amplification of cDNA ends technique; its full length is 1537 bp and contains an open reading frame of 450 amino acid residues with two N-glycosylation sites and four protein kinase C phosphorylation sites. The deduced amino acid sequences did show significant homology to the a-tubulin from other plants that has been reported to be a pollen-specific protein and could be correlated with plant cytoplasm-nucleus-interacted male sterility. We named this complete cDNA Tua1. The nucleotide and amino acid sequence data of Tua1 have been recorded in the GenBank sequence database. This Tua1 gene was cloned into the pET-32a expression system and expressed in Escherichia coli BL21trxB(DE3). The molecular weight of expressed protein was deduced to be approximately 49 kDa. Western blot analysis was used to identify the temporal expression of Tua1 in tea plant. Further studies of the effect of Tua1 protein on pollen tube growth indicated the Tua1 solution obviously promoted the growth of tea pollen tube.

Base Sequence↗
PubMed2006

[pBR322-Red mediated gene knockin, sites and expression in E. coli chromosome].

Genes lacZ, lacY and lacA in the lac opron of E. coli chromosome were respectively substituted with gene luc by using plasmid pBR322-Red, selection-counterselection system kan/sacB and various strategies of Red homologous recombination including Red mediated linearized double-stranded DNA homologous recombination and Red mediated recombineering with overlapping single stranded DNA oligonucleotides. Then, a series of new strains, CWL2, CWL4 and CWL6, were constructed and we found that they can express protein Luc efficiently. To further study the expression of exogenous genes at the site of lacZ, we have constructed a strain named CWD1 by knockin the cholera toxin B subunit(ctxb) gene at the lacZ site, then we found that CWD1 can express protein CTB efficiently and CTB was secreted out of the cell. So we assured that the sites of structure genes in the lac operon of Escherichia coli chromosome were suitable for expressing foreign genes.

Cholera Toxin↗
PubMed2006

[Outcome analysis of conservative treatment of well-differentiated endometrial adenocarcinoma and severe atypical hyperplasia in young women].

OBJECTIVE: To evaluate the effect of hormonal therapy on well-differentiated endometrial adenocarcinoma and severe atypical hyperplasia in young women aged 35 years and younger. METHODS: We retrospectively studied the clinical characteristics of 25 patients under 35 years of age (average: 28.6) diagnosed with well-differentiated endometrial adenocarcinoma or severe atypical hyperplasia, who were treated with progestin in Peking Union Medical College Hospital from 1991 to 2005. According to pathologic results, 25 patients were divided into two groups: 8 cases of endometrial carcinoma and 17 cases of severe atypical hyperplasia. In the endometrial carcinoma group, pelvic ultrasound, MRI, chest X-ray and serum CA(125) were used in pretreatment evaluation. Progesterone receptors were examined with immunohistochemical method. All patients received dilation and curettage of endometrium every 1-6 months as an assessment of treatment results. For chemotherapy, most of them were treated with medroxyprogesterone acetate. RESULTS: Six cases (6/7) in endometrial carcinoma group, and 17 cases (100%) in severe atypical hyperplasia group responded to treatment respectively; among them, 5 cases (5/7) and 14 cases (82%) had complete response, which was defined as the absence of any carcinoma or hyperplasia on endometrial samplings; one case (1/5) and 3 cases (21%) recurred within 6 to 30 months after their complete response. Follow-up on 14 patients with complete response, and the desire for childbearing showed that none of the 4 cases of endometrial carcinoma had conceived a pregnancy and 4 (40%) patients had pregnancy for totally 7 times of 10 cases of severe atypical hyperplasia. Three patients delivered full-term fetuses with induced ovulation, one of whom had artificial abortion 3 times after her delivery. One patient was lost to follow up after her spontaneous pregnancy. CONCLUSIONS: Progestin therapy is a good choice for young women having fertility desires diagnosed with well-differentiated endometrial adenocarcinoma or severe atypical hyperplasia. Endometrial carcinoma patients should be selected carefully before therapy. Pregnant rate is not satisfactory after conservative treatment. Assistant reproductive technology is potentially helpful to improve pregnant rate of patients responded to progestin therapy.

Adult↗
PubMed2006

[Clinical evaluation of high-risk HPV detection by hybrid capture II in screening cervical intraepithelial neoplasma].

OBJECTIVE: To evaluate the value of high-risk HPV (hrHPV) detection by Hybrid Capture II (HC2) in screening cervical intraepithelial neoplasm (CIN). METHODS: Totally 723 patients who had received a dual screening with thinprep cytologic test (TCT) and HC2 in our department were analyzed retrospectively. Among them, 350 patients received a triple examination with TCT, HC2, and colposcopic biopsy. RESULTS: Among the 723 patients, the incidences of hrHPV infection with atypical squamous cell (ASC), low squamous intraepithelial lesion, and high squamous intraepithelial lesion were 70.7% (94/133), 88.9% (249/280), and 90.9% (90/99), respectively, significantly higher than 55.5% (117/211), the incidence of hrHPV infection with normal cytological results (P = 0.005, P < 0.001, P < 0.001, respectively). Among 350 cases who were received triple examination, the incidence of hrHPV infection with cervical intraepithelial neoplasia (CIN) 1 and CIN 2 were 88.9% (72/81) and 96.3% (52/54), significantly higher than 77.7% (153/197), the incidence of hrHPV infection with normal pathological results (P = 0.03, P = 0.002); The incidence of hrHPV infection with CIN 3 and squamous cancer were 91.7% (11/12) and 100.0% (6/6), also higher than normal cases. Among these 350 cases, the incidence of hrHPV infection with ASC was 79.3% (69/87). The incidence of CIN 2-3 with ASC and hrHPV infection was 38.0%, significantly higher than the incidence of CIN 2-3 with ASC and without hrHPV infection (5.9%) (P = 0.04). CONCLUSION: hrHPV infection has a close relation with CIN, and the incidence of hrHPV infection increases along with the severity of CIN.

Adolescent↗
PubMed2006

[Distribution of polybrominated diphenyl ethers in aquatic species from the Pearl River Estuary].

Polybrominated diphenyl ethers (PBDEs) were detected in biota samples collected from the Pearl River Estuary. The concentrations of sigma10 PBDEs (BDE28, 47, 66, 100, 99, 85, 154, 153, 138, 183) in fish species (including Platycephalus indicus, Pseudosiaena crocea , Pampus argenteus, Cynoglossus robustus, and Harpodon nehereus), shrimps (including Metapenaeus ensis and Metapenaeus affinis) and Squilla oratoria were from 37.8 ng x g(-1) to 407.1 ng x g(-1) (normalized to lipid), from 49.0 ng x g(-1) to 239.1 ng x g(-1) and from 142 ng x g(-1) to 444.5 ng x g(-1), respectively. BDE47 was the dominant congener in all biota samples, with a contribution to sigma10 PBDEs ranging from 53.7% to 66.9%. Differences in concentrations of PBDEs and PBDE patterns in different species may be related to the different feeding habit, living environment and uptaking or elimination rate. High ratios of concentrations of PBDEs in liver /muscle in fish species indicated that PBDEs tended to accumulate more in liver than in muscle.

Animals↗
PubMed2006

[Screening for G1528C mutation in mitochondrial trifunctional protein gene in pregnant women with severe preeclampsia and new born infant].

OBJECTIVE: Severe preeclampsia, and hemolysis, elevated liver enzymes, and low platelet syndrome (HELLP) are serious complications of pregnancy, and evidence suggests a genetic basis for these conditions. A G1528C mutation in the alpha-subunit of the mitochondrial trifunctional protein (MTP) gene has been identified in association with these conditions. The aim of this study is to explore the carrier rate of the G1528C mutation in the MTP gene in pregnant women with severe preeclampsia, HELLP syndrome and in their newborns, as well as in a normal pregnant population, so as to determine its association with maternal liver disease among women in Beijing. METHODS: A multicenter, prospective, case control study was carried out. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to screen the G1528C mutations in the MTP gene. One hundred and forty cord blood samples from cases with severe preeclampsia (n = 130) and HELLP syndrome (n = 10) were collected. Ninety maternal peripheral blood samples among them (84 from severe preeclampsia and 6 from HELLP syndrome) were also collected for screening the common disease-causing mutation in Caucasians. Five hundred and sixty cord blood samples and 90 maternal peripheral blood samples obtained from normal pregnant women served as controls. RESULTS: The G1528C mutations in the MTP gene were not found in samples from women with severe preeclampsia and their newborns, from women with HELLP syndrome and their new borns, as well as in samples from the normal pregnant women and their new borns. CONCLUSIONS: The common disease-causing mutation of G1528C in MTP gene in Caucasians is probably not a common mutation in Chinese Han people in Beijing. Further study is needed to expand the sample size among HELLP syndrome and maternal liver diseases in Chinese population.

Case-Control Studies↗
PubMed2005

Quantification of intrinsic water use efficiency along a moisture gradient in Northeastern China.

Water use efficiency (WUE) is an important ecophysiological characteristic of plants, especially in semiarid and arid regions. At the scale of community or ecosystem, WUE is difficult to quantify because the amount of water used per unit dry mass production is a function of microclimatic variables and species composition. In this study, we analyzed corrected intrinsic water use efficiency (IWUE(s)) of grass and shrub species along the western segment of the Northeast China Transect (NECT) and the relationship between IWUE(s) and mean annual rainfall, habitat degradation status, vegetation type, and plant functional type (C3 versus C4) at 22 survey sites. Site intrinsic water use efficiency (IWUE(v)) and its relationship with the aforementioned site variables were analyzed based on species frequencies at each site. First, it was concluded that photosynthetic pathway played a very important role in determining species IWUE(s). Mean IWUE(s) for C4 species was approximately double that of C3 species. Second, mean annual rainfall, vegetation type, and site degradation status significantly affected IWUE(s) (p < 0.01). Mean IWUE(s) at degraded sites was twice as high as that at nondegraded sites. The mean IWUE(s) for meadows was significantly higher than those for other vegetation types (p < 0.05). Third, the frequency of occurrence of C4 plants explained 36% of the variance in IWUE(v) across the survey sites. The mean frequency of C4 occurrence at degraded sites was more than double that at nondegraded sites. Consequently, mean IWUE(v) at degraded sites was more than double that at nondegraded sites. Dominant C4 species in saline-alkaline areas tended to have higher intrinsic WUE than dominant C4 species in sandy shrub communities.

China↗
PubMed2005

Effects of rhubarb on isolated gastric muscle strips of guinea pigs.

AIM: To study the effects of rhubarb (dried root of Rheum officinale Baill.) on contractile activity of isolated gastric muscle strips of guinea pigs and its possible mechanism. METHODS: A total of 48 guinea pigs were killed to remove the whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parallel to the circular fibers, muscle strips were cut from the body. Each isolated gastric muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution, constantly warmed by water jacket at 37 degrees and bubbled continuously with a mixed gas of 950 mL/L O2 and 50 mL/L CO2. After being incubated for 1 h with 1 g tension, rhubarb of varied concentrations (1%, 2%, 7%, 20% and 70%) was added cumulatively into the tissue chamber at intervals of 2 min. Atropine (10(-6) mol/L) or isoptin (5 x 10(-8) mol/L) or hexamethonium (10(-5) mol/L) was given 2 min before the administration of rhubarb. The isometrical response was measured with an ink-writing recorder. RESULTS: Rhubarb dose dependently increased the resting tension of gastric body circular muscle (CM) (r = 0.726, P<0.05). Atropine (r = 0.829, P<0.05), isoptin (r = 0.764, P<0.05) and hexamethonium (r = 0.797, P<0.05) did not affect its action in a dose-related manner. Atropine apparently reduced the increasing action of 1%, 3%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Isoptin inhibited the effect of 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Hexamethonium reduced the increasing action of 1%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Rhubarb increased the contractile frequency of CM of body. While atropine, isoptin and hexamethonium did not inhibit the contractile frequency of gastric body CM in comparison with rhubarb at the same concentration, rhubarb at the highest concentration (100%) decreased the mean contractile amplitude of gastric body CM. Atropine, isoptin and hexamethonium did not affect the mean contractile amplitude of gastric body CM compared to rhubarb at the same concentration. CONCLUSION: Rhubarb has exciting actions on isolated gastric smooth muscle strips of guinea pig. The exciting action of rhubarb is partly mediated via cholinergic M receptor, cholinergic N receptor and L-type calcium channel.

Animals↗
PubMed2005

PARP-10, a novel Myc-interacting protein with poly(ADP-ribose) polymerase activity, inhibits transformation.

The proto-oncoprotein c-Myc functions as a transcriptional regulator that controls different aspects of cell behavior, including proliferation, differentiation, and apoptosis. In addition, Myc proteins have the potential to transform cells and are deregulated in the majority of human cancers. Several Myc-interacting factors have been described that mediate part of Myc's functions in the control of cell behavior. Here, we describe the isolation of a novel 150 kDa protein, designated PARP-10, that interacts with Myc. PARP-10 possesses domains with homology to RNA recognition motifs and to poly(ADP-ribose) polymerases (PARP). Molecular modeling and biochemical analysis define a PARP domain that is capable of ADP-ribosylating PARP-10 itself and core histones, but neither Myc nor Max. PARP-10 is localized to the nuclear and cytoplasmic compartments that is controlled at least in part by a Leu-rich nuclear export sequence (NES). Functionally, PARP-10 inhibits c-Myc- and E1A-mediated cotransformation of rat embryo fibroblasts, a function that is independent of PARP activity but that depends on a functional NES. Together, our findings define a novel PARP enzyme involved in the control of cell proliferation.

Amino Acid Sequence↗
PubMed2005

[Screening for the G1528C mutation in long chain fatty acid oxidation enzyme in Han nationality in Beijing population].

OBJECTIVE: To explore the carrier rate of G1528C mutation in alpha-subunit gene of MTP in Chinese newborns. METHODS: 1 200 cases of cord blood samples were taken in pregnant women with Han nationality in Chinese. PCR-RFLP analysis was conducted for detection of G1528C mutation. RESULTS: No. G1528C mutations in LCHAD gene were found in these study subjects. CONCLUSION: G1528C is probably not the common prevalent mutation in MTP gene in Chinese. Different prevalent mutation between Chinese and Western white people needs further study.

China↗