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Biomedical subjects

Y Cui

Publications and source records attributed to Y Cui.

At least 19 recordsLinked to original sources
PubMed2006

The major 8p22 tumor suppressor DLC1 is frequently silenced by methylation in both endemic and sporadic nasopharyngeal, esophageal, and cervical carcinomas, and inhibits tumor cell colony formation.

Identification of tumor suppressor genes (TSG) silenced by methylation uncovers mechanisms of tumorigenesis and identifies new epigenetic tumor markers for early cancer detection. Both nasopharyngeal carcinoma (NPC) and esophageal carcinoma are major tumors in Southern China and Southeast Asia. Through expression subtraction of NPC, we identified Deleted in Liver Cancer 1 (DLC1)/ARHGAP7 (NM_006094)--an 8p22 TSG as a major downregulated gene. Although expressed in all normal tissues, DLC1 was silenced or downregulated in 11/12 (91%) NPC, 6/15 (40%) esophageal, 5/8 (63%) cervical and 3/9 (33%) breast carcinoma cell lines. No genetic deletion of DLC1 was detected in NPC although a hemizygous deletion at 8p22-11 was found by 1-Mb array-CGH in some cell lines. We then located the functional DLC1 promoter by 5'-RACE and promoter activity assays. This promoter was frequently methylated in all downregulated cell lines and in a large collection of primary tumors including 89% (64/72) NPC (endemic and sporadic types), 51% (48/94) esophageal, 87% (7/8) cervical and 36% (5/14) breast carcinomas, but seldom in paired surgical marginal tissues and not in any normal epithelial tissue. The transcriptional silencing of DLC1 could be reversed by 5-aza-2'-deoxycytidine or genetic double knock-out of DNMT1 and DNMT3B. Furthermore, ectopic expression of DLC1 in NPC and esophageal carcinoma cells strongly inhibited their colony formation. We thus found frequent epigenetic silencing of DLC1 in NPC, esophageal and cervical carcinomas, and a high correlation of methylation with its downregulation, suggesting a predominant role of epigenetic inactivation. DLC1 appears to be a major TSG implicated in the pathogenesis of these tumors, and should be further tested as a molecular biomarker in patients with these cancers.

Base Sequence↗
PubMed2006

Role of the JAK-STAT pathway in protection of hydrogen peroxide preconditioning against apoptosis induced by oxidative stress in PC12 cells.

The aim of this study was to investigate the role of JAK-STAT pathway in the cytoprotection afforded by preconditioning with H(2)O(2). It was shown that (1) Preconditioning with 100 micromol/L H(2)O(2) can markedly protect PC12 cells against apoptosis and cytotoxicity induced by 300 micromol/L H(2)O(2); (2) The expression and tyrosine phosphorylation of JAK2, not JAK1 were rapidly increased at 5 min after H(2)O(2) preconditioning; (3) The expression of STAT1 and STAT3 were significantly increased at 15 min after H(2)O(2) preconditioning, and the pTyr-STAT1 and pTyr-STAT3 were markedly increased at 60 min after H(2)O(2) preconditioning; (4) Pretreatment with the JAK inhibitor AG-490 (10 micromol/L) 20 min before H(2)O(2) preconditioning blocked not only the activation of JAK2, STAT1 and STAT3, but also the cytoprotection of H(2)O(2) preconditioning against apoptosis and cytotoxicity induced by oxidative stress. These findings suggested that preconditioning with H(2)O(2) activated the JAK-STAT pathway that played an important role in the cytoprotection induced by H(2)O(2) preconditioning.

Animals↗
PubMed2006

Curcumin protects PC12 cells against 1-methyl-4-phenylpyridinium ion-induced apoptosis by bcl-2-mitochondria-ROS-iNOS pathway.

The aim of present study is to explore the cytoprotection of curcumin against 1-methyl-4-phenylpridinium ions (MPP(+))-induced apoptosis and the molecular mechanisms underlying in PC12 cells. Our findings indicated that MPP(+) significantly reduced the cell viability and induced apoptosis of PC12 cells. Curcumin protected PC12 cells against MPP(+)-induced cytotoxicity and apoptosis not only by inducing overexpression of Bcl-2, but also reducing the loss of mitochondrial membrane potential (MMP), an increase in intracellular reactive oxygen species (ROS) and overexpression of inducible nitric oxide synthase (iNOS). The selective iNOS inhibitor AG partly blocked MPP(+)-induced apoptosis of PC12 cells. The results of present study suggested that the cytoprotective effects of curcumin might be mediated, at least in part, by the Bcl-2-mitochondria-ROS-iNOS pathway. Because of its non-toxic property, curcumin could be further developed to treat the neurodegenerative diseases which are associated with oxidative stress, such as Parkinson's disease (PD).

1-Methyl-4-phenylpyridinium↗
PubMed2006

Genetic heterogeneity in acrokeratosis verruciformis of Hopf.

BACKGROUND: Acrokeratosis verruciformis of Hopf (AKV) is a rare genodermatosis characterized by multiple flat-topped, flesh-coloured papules on the dorsa of hands and feet, and punctuate keratoses on the palms and soles. A mutation in the ATP2A2 gene has been shown to be associated with AKV and with Darier's disease (DD). OBJECTIVES: To explore the molecular aetiology of AKV and DD. METHODS: We investigated the clinical and histological information in two families and a sporadic case with AKV and one family and a sporadic case with DD in China. Mutation analysis of ATP2A2 was performed by PCR and direct sequencing, and genotyping and linkage analysis performed using six polymorphic microsatellite markers spanning the locus at 12q23-12q24 containing ATP2A2. RESULTS: Mutational analysis showed no mutation in ATP2A2 among the AKV patients, but we found two novel mutations (p.C318F and p.M719fs) in the DD patients. The genotyping and linkage analysis results revealed no linkage evidence of the locus at 12q23-12q24 in a large AKV family. CONCLUSIONS: Our findings provide evidence for the genetic heterogeneity of AKV and demonstrate that mutations in genes other than ATP2A2 are responsible for AKV in a proportion of the Chinese population.

Acrodermatitis↗
PubMed2006

Growth of aligned ZnO nanorods.

Growth of high-density and aligned ZnO nanorods on ZnO film substrate has been demonstrated using vapor-transport of thermally evaporated Zn metal powders followed by condensation. Morphological studies show that the nanorods grow preferentially from a hexagonal ZnO base with a uniform hexagonal structure following three-dimensional island-like growth mechanism. Structural and spectroscopic properties clearly indicate that the nanorods are relatively good and defect-free in quality. These nanorods have potential for technological implications.

Crystallization↗
PubMed2005

Observation of the anomalous increase of the longitudinal energy spread in a space-charge-dominated electron beam.

We report a new experimental study of the growth of longitudinal energy spread in a space-charge-dominated electron beam, with a beam energy of several keV and beam current of approximately 100 mA. At relatively low beam densities, we measure growing energy spreads with distance along the transport channel, which are in remarkably good agreement with the theory of energy relaxation via Coulomb collisions. At higher beam densities, however, anomalous energy spreads exceeding the predictions of the relaxation theory are observed, which, we believe, could be caused by collective longitudinal-transverse instabilities observed in computer simulation studies. The onset of these instabilities occurs after several plasma periods according to calculations.

Journal Article↗
PubMed2005

Standard treatment for Helicobacter pylori infection is suboptimal in non-ulcer dyspepsia compared with duodenal ulcer in Chinese.

BACKGROUND: Recent studies suggest that the Helicobacter pylori eradication rate in patients with non-ulcer dyspepsia is lower when compared to patients with peptic ulcer diseases. AIM: The aim of this study was to study the efficacy of triple therapy for H. pylori infection in patients with duodenal ulcer vs. patients with non-ulcer dyspepsia. METHODS: A total of 582 Chinese patients with proven H. pylori infection were recruited to receive: omeprazole 20 mg, amoxicillin 1000 mg and clarithromycin 500 mg all given twice daily for 7 days (OCA regime). Endoscopy with rapid urease test, histology and culture were performed before treatment. Post-treatment H. pylori status was determined by (13)C-urea breath test. Metronidazole, clarithromycin and amoxicillin resistance was defined as minimum inhibitory concentration (MIC) of >8 microg/mL, >1 microg/mL and >1 microg/mL, respectively. RESULTS: A significantly higher (intention-to-treat/per-protocol) eradication rate was found in patients with duodenal ulcer than those with non-ulcer dyspepsia (91/94% vs. 84/88% respectively, P = 0.011 and P = 0.016). Clarithromycin resistance rate was higher in patients with non-ulcer dyspepsia than those with duodenal ulcer (14% vs. 6%, P = 0.015). Clarithromycin resistance (40% vs. 5%, P < 0.001, OR 12, 95% CI: 5.7-24.3) and the diagnosis of non-ulcer dyspepsia (91% vs. 84%, P = 0.011, OR 2.0, 95% CI: 1.2-3.3) significantly affected the success of H. pylori eradication. CONCLUSION: Clarithromycin resistance accounts for the significantly lower and suboptimal H. pylori eradication rate of OCA regimen in Chinese patients with non-ulcer dyspepsia compared to those with duodenal ulcer.

Adolescent↗
PubMed2005

Refined localization of a punctate palmoplantar keratoderma gene to a 5.06-cM region at 15q22.2-15q22.31.

BACKGROUND: Punctate palmoplantar keratoderma (PPK) is a rare autosomal dominant cutaneous disorder characterized by numerous hyperkeratotic papules distributed on the palms and soles. Two loci for punctate PPK were recently found to be located on 8q24.13-8q24.21 and 15q22-15q24. However, no genes for this disease have been identified to date. Objectives To refine the previously mapped regions and to identify the disease gene locus in a four-generation Chinese family with punctate PPK. METHODS: Genetic linkage analysis was carried out in this family using microsatellite markers on chromosomes 8q and 15q. Two-point linkage analysis was performed using Linkage programs version 5.10 and the haplotype was constructed using Cyrillic version 2.02 software. RESULTS: We failed to confirm our previous locus at 8q24.13-8q24.21, but significant evidence for linkage was observed in the region of 15q with a maximum two-point LOD score of 5.38 at D15S153 (theta = 0.00). Haplotype analysis localized the punctate PPK locus within the region defined by D15S651 and D15S988. This region overlaps by 5.06 cM with the previously reported punctate PPK region. CONCLUSIONS: This study refines a disease gene causing punctate PPK to a 5.06-cM interval at 15q22.2-15q22.31.

Adolescent↗
PubMed2005

Elevated temperature enhances virulence of Erwinia carotovora subsp. carotovora strain EC153 to plants and stimulates production of the quorum sensing signal, N-acyl homoserine lactone, and extracellular proteins.

Erwinia carotovora subsp. atroseptica, E. carotovora subsp. betavasculorum, and E. carotovora subsp. carotovora produce high levels of extracellular enzymes, such as pectate lyase (Pel), polygalacturonase (Peh), cellulase (Cel), and protease (Prt), and the quorum-sensing signal N-acyl-homoserine lactone (AHL) at 28 degrees C. However, the production of these enzymes and AHL by these bacteria is severely inhibited during growth at elevated temperatures (31.2 degrees C for E. carotovora subsp. atroseptica and 34.5 degrees C for E. carotovora subsp. betavasculorum and most E. carotovora subsp. carotovora strains). At elevated temperatures these bacteria produce high levels of RsmA, an RNA binding protein that promotes RNA decay. E. carotovora subsp. carotovora strain EC153 is an exception in that it produces higher levels of Pel, Peh, Cel, and Prt at 34.5 degrees C than at 28 degrees C. EC153 also causes extensive maceration of celery petioles and Chinese cabbage leaves at 34.5 degrees C, which correlates with a higher growth rate and higher levels of rRNA and AHL. The lack of pectinase production by E. carotovora subsp. carotovora strain Ecc71 at 34.5 degrees C limits the growth of this organism in plant tissues and consequently impairs its ability to cause tissue maceration. Comparative studies with ahlI (the gene encoding a putative AHL synthase), pel-1, and peh-1 transcripts documented that at 34.5 degrees C the RNAs are more stable in EC153 than in Ecc71. Our data reveal that overall metabolic activity, AHL levels, and mRNA stability are responsible for the higher levels of extracellular protein production and the enhanced virulence of EC153 at 34.5 degrees C compared to 28 degrees C.

4-Butyrolactone↗
PubMed2004

Molecular and functional characterization of a vasotocin-sensitive aquaporin water channel in quail kidney.

Both mammals and birds can concentrate urine hyperosmotic to plasma via a countercurrent multiplier mechanism, although evolutionary lines leading to mammals and birds diverged at an early stage of tetrapod evolution. We reported earlier (Nishimura H, Koseki C, and Patel TB. Am J Physiol Regul Integr Comp Physiol 271: R1535-R1543, 1996) that arginine vasotocin (AVT; avian antidiuretic hormone) increases diffusional water permeability in the isolated, perfused medullary collecting duct (CD) of the quail kidney. In the present study, we have identified an aquaporin (AQP) 2 homolog water channel in the medullary cones of Japanese quail, Coturnix coturnix (qAQP2), by RT-PCR-based cloning techniques. A full-length cDNA contains an 822-bp open reading frame that encodes a 274-amino acid sequence with 75.5% identity to rat AQP2. The qAQP2 has six transmembrane domains, two asparagine-proline-alanine (NPA) sequences, and putative N-glycosylation (asparagine-124) and phosphorylation sites (serine-257) for cAMP-dependent protein kinase. qAQP2 is expressed in the membrane of Xenopus laevis oocytes and significantly increased its osmotic water permeability (P(f)), inhibitable (P < 0.01) by mercury chloride. qAQP2 mRNA (RT-PCR) was detected in the kidney; medullary mRNA levels were higher than cortical levels. qAQP2 protein that binds to rabbit anti-rat AQP2 antibody is present in the apical/subapical regions of both cortical and medullary CDs from normally hydrated quail, and the intensity of staining increased only in the medullary CDs after water deprivation or AVT treatment. The relative density of the approximately 29-kDa protein band detected by immunoblot from the medullary cones was modestly higher in water-deprived/AVT-treated quail. The results suggest that 1) medullary CDs of quail kidneys express a mercury-sensitive functioning qAQP2 water channel, and 2) qAQP2 is at least partly regulated by an AVT-dependent mechanism. This is the first clear identification of AQP2 homolog in nonmammalian vertebrates.

Algorithms↗
PubMed2004

Selection of 2'-fluoro-modified RNA aptamers for alleviation of cocaine and MK-801 inhibition of the nicotinic acetylcholine receptor.

The nicotinic acetylcholine receptor (nAChR) belongs to a group of five structurally related proteins that regulate signal transmission between approximately 10(12) cells of the mammalian nervous system. Many therapeutic agents and abused drugs inhibit the nAChR, including the anti-convulsant MK-801 and the abused drug cocaine. Many attempts have been made to find compounds that prevent inhibition by cocaine. Use of transient kinetic techniques to investigate the inhibition of the receptor by MK-801 and cocaine led to an inhibition mechanism not previously proposed. The mechanism led to the development of combinatorially synthesized RNA ligands that alleviate inhibition of the receptor. However, these ligands are relatively unstable. Here we determined whether much more stable 2'-fluoro-modified RNA ligands can be prepared and used to study the alleviation of receptor inhibition. Two classes of 2'-fluoro-modified RNA ligands were obtained: One class binds with higher affinity to the cocaine-binding site on the closed-channel form and, as predicted by the mechanism, inhibits the receptor. The second class binds with equal or higher affinity to the cocaine-binding site on the open-channel form and, as predicted by the mechanism, does not inhibit the receptor, and does alleviate cocaine and MK-801 inhibition of the nAChR. The stability of these 2'-fluoro-RNAs expands the utility of these ligands.

Animals↗
PubMed2004

Determinants of perioperative morbidity and mortality after pneumonectomy.

BACKGROUND: Pneumonectomy remains a relatively high-risk procedure. However, the underlying mechanism is still unknown. Thus, the effort to find out predisposing factors for surgical risks continues. We investigated the effect of both water-load control and sampling lymphadenectomy technique on perioperative morbidity and mortality after pneumonectomy. MATERIAL AND METHODS: A hundred and three consecutive patients undergoing simple pneumonectomy were included in the prospective study. Pneumonectomy was performed for lung cancer in 92 patients and for benign diseases in 11 cases; 81 patients were male and 22 female, and the mean age was 53.4 +/- 11.4 years. Both sampling and completion lymphadenectomy techniques were used randomly. Water-load was carefully limited to values as low as possible, depending on stable hemodynamics during and after operation. RESULTS: There were no deaths, and none of the patients needed postoperative mechanical ventilation. Major complications included dyspnea in 9 patients and supraventricular arrhythmias in 13 patients. Completion lymphadenectomy increased morbidity in both right and left pneumonectomy. CONCLUSIONS: Both water-load limitation and sampling lymphadenectomy technique may decrease morbidity and mortality after pneumonectomy.

Adult↗
PubMed2004

Simultaneous carbon and nitrogen removal in anoxic-aerobic circulating fluidized bed biological reactor (CFBBR).

Biological nutrient removal (BNR) in municipal wastewater treatment to remove carbonaceous substrates and nutrients, has recently become increasingly popular worldwide due to increasingly stringent regulations. Biological fluidized bed (BFB) technology, which could be potentially used for BNR, can provide some advantages such as high efficiency and a compact structure. This work shows the results of simultaneous elimination of organic carbon and nitrogen using a circulating fluidized bed biological reactor (CFBBR, which has been developed recently for chemical engineering processes. The CFBBR has two fluidized beds, running as anoxic and aerobic processes to accomplish simultaneous nitrification and denitrification, with continuous liquid recirculation through the anoxic bed and the aerobic bed. Soluble COD concentrations in the effluent ranging from 4 to 20 mg l(-1) were obtained at varying COD loading rates; ammonia nitrogen removal efficiencies averaged in excess of 99% at a minimum total hydraulic retention time (HRT) of 2.0 hours over a temperature range of 25 degrees C to 28 degrees C. Effluent nitrate nitrogen concentration of less than 5 mg l(-1) was achieved by increasing effluent recycle rate. No nitrite accumulation was observed either in the anoxic bed or in the aerobic bed. The system was able to treat grit chamber effluent wastewater at a HRT of 2.0 hours while achieving average effluent BOD, COD, NH3-N, TKN, nitrates, total phosphate, TSS and VSS concentrations of 10 mg l(-1), 18 mg l(-1), 1.3 mg l(-1), 1.5 mg l(-1), 7 mg l(-1), 2.0 mg l(-1), 10 mg l(-1) and 8 mg l(-1) respectively. The CFBBR appears to be not only an excellent alternative for conventional activated sludge type BNR technologies but also capable of processing much higher loadings that are suitable for industrial applications.

Bacteria, Aerobic↗
PubMed2004

Refined localization of dyschromatosis symmetrica hereditaria gene to a 9.4-cM region at 1q21-22 and a literature review of 136 cases reported in China.

BACKGROUND: Dyschromatosis symmetrica hereditaria (DSH) is an autosomal dominant pigmentary genodermatosis characterized by hyperpigmented and hypopigmented macules on the extremities, which has recently been mapped to an 11.6-cM interval on chromosome 1q11-21. So far, most cases of DSH have been reported in Japan and dermatologists around the world might think this disorder mainly occurs in Japan. In fact, there are 17 DSH families including 136 cases reported in China since 1980, but most of them are described in Chinese. OBJECTIVES: To refine the previously mapped region that facilitates the identification of the DSH gene and to delineate the clinical and genetic features of Chinese DSH cases by a literature review of 136 cases reported in China. METHODS: We performed genotyping and linkage analysis using polymorphic microsatellite markers at 1q11-22 in two Chinese DSH families, and reviewed all of the DSH cases reported in China since 1980. RESULTS: A cumulative maximum two-point lod score of 3.68 was produced with marker D1S506 at a recombination frequency of theta = 0.00 in these two families. Haplotype analysis refined the DSH locus to a 9.4-cM interval flanked by D1S2343 and D1S2635. The genetic and clinical features of Chinese cases with DSH were summarized. In some Chinese cases, hyperpigmented and hypopigmented macules were scattered on the neck and chest, but among Japanese patients there were no similar skin lesions to be reported on these sites. CONCLUSIONS: This study confirms linkage of DSH to a previously mapped region and refines the DSH gene to a 9.4-cM interval at 1q21-22. Likewise, the literature review indicates that DSH is not an uncommon disorder in China and the differences in the distribution of skin lesions could be related to race and environment.

Adult↗
PubMed2004

Refinement of a locus for Marie Unna hereditary hypotrichosis to a 1.1-cM interval at 8p21.3.

BACKGROUND: Marie Unna hereditary hypotrichosis (MUHH) is a rare autosomal congenital alopecia with progressive hair loss starting in early childhood and accelerating at puberty. A locus for MUHH has been mapped on chromosome 8p21 but no genes for MUHH have been identified to date. OBJECTIVES: To refine the MUHH locus to a narrow chromosome region to facilitate cloning of the gene. METHODS: We performed genotyping and linkage analysis in a multigeneration Chinese family with MUHH, using 18 high-density microsatellite markers spanning the previously mapped interval at 8p21. RESULTS: Significant evidence for linkage was observed in this region, with a maximum two-point LOD score of 3.01 (theta = 0). Haplotype analysis localized the MUHH locus within the region defined by D8S282 and D8S1839. This region overlaps by 1.1-cM with the previously reported MUHH region and represents a physical distance of about 380 kb. CONCLUSIONS: This study provides a refined map location (1.1 cM) for isolation of the gene causing MUHH. These data also indicate the existence of a common MUHH locus at 8p21.3 between affected caucasian and Chinese families.

Aged↗
PubMed2004

Marie Unna hereditary hypotrichosis: report of a Chinese family and evidence for genetic heterogeneity.

Marie Unna hereditary hypotrichosis (MUHH) is a rare autosomal dominant disorder with progressive hair loss starting in early childhood and aggravating at puberty. Several studies have mapped the MUHH gene to chromosome 8p21. Here we report a Chinese MUHH family with variable phenotypes. All affected individuals have anomalies affecting both hair density and hair shafts. Major clinical characteristics, disease history and histological examination support the diagnosis of MUHH, but the features of scarring in this kindred are modest and none of the patients have vertex hair loss, which is in contrast with typical MUHH. We now report genotyping and linkage analysis using 11 polymorphic microsatellite markers spanning the MUHH locus at 8p. Two-point linkage analysis using these markers revealed significant exclusion of this locus (log of the odds scores < - 2) at Theta = 0 indicating that there is a range of clinical presentations in MUHH, and that more than one genetic locus is responsible for the disorder.

Adult↗