Biomedical subjects

Qing Wang

Publications and source records attributed to Qing Wang.

At least 55 records · Page 3Linked to original sources

PubMed2006

DFT-INDO/S modeling of new high molar extinction coefficient charge-transfer sensitizers for solar cell applications.

A new ruthenium(II) complex, tetrabutylammonium [ruthenium (4-carboxylic acid-4'-carboxylate-2,2'-bipyridine)(4,4'-di(2-(3,6-dimethoxyphenyl)ethenyl)-2,2'-bipyridine)(NCS)(2)] (N945H), was synthesized and characterized by analytical, spectroscopic, and electrochemical techniques. The absorption spectrum of the N945H sensitizer is dominated by metal-to-ligand charge-transfer (MLCT) transitions in the visible region, with the lowest allowed MLCT bands appearing at 25 380 and 18 180 cm(-1). The molar extinction coefficients of these bands are 34 500 and 18 900 M(-1) cm(-1), respectively, and are significantly higher when compared to than those of the standard sensitizer cis-dithiocyanatobis(4,4'-dicarboxylic acid-2,2'-bipyridine)ruthenium(II). An INDO/S and density functional theory study of the electronic and optical properties of N945H and of N945 adsorbed on TiO(2) was performed. The calculations point out that the top three frontier-filled orbitals have essentially ruthenium 4d (t(2g) in the octahedral group) character with sizable contribution coming from the NCS ligand orbitals. Most critically the calculations reveal that, in the TiO(2)-bound N945 sensitizer, excitation directs charge into the carboxylbipyridine ligand bound to the TiO(2) surface. The photovoltaic data of the N945 sensitizer using an electrolyte containing 0.60 M butylmethylimidazolium iodide, 0.03 M I(2), 0.10 M guanidinium thiocyanate, and 0.50 M tert-butylpyridine in a mixture of acetonitrile and valeronitrile (volume ratio = 85:15) exhibited a short-circuit photocurrent density of 16.50 +/- 0.2 mA cm(-2), an open-circuit voltage of 790 +/- 30 mV, and a fill factor of 0.72 +/- 0.03, corresponding to an overall conversion efficiency of 9.6% under standard AM (air mass) 1.5 sunlight, and demonstrated a stable performance under light and heat soaking at 80 degrees C.

Journal Article↗

PubMed2006

Controlled release of avermectin from porous hollow silica nanoparticles: influence of shell thickness on loading efficiency, UV-shielding property and release.

Preparation and characterization of porous hollow silica nanoparticles (PHSNs), with various shell thicknesses in the range of 5-45 nm and a pore diameter of about 4-5 nm, were investigated. PHSNs were fabricated via a sol-gel route with two different structure-directing templates and their shell thickness could be controlled by adjusting the reactant ratio of Na2SiO3.9H2O/CaCO3. The produced PHSNs were applied as controlled pesticide release carriers to study the effects of the shell thickness on the loading efficiency for avermectin, the UV-shielding property for the loaded avermectin and the controlled release of the loaded avermectin from the carriers. It was found that the amount of loaded avermectin decreases with the increase of shell thickness, while the UV-shielding property of PHSNs for avermectin is improved as the shell gets thicker. In addition, the shell thickness has a significant impact on avermectin release. Increasing the shell thickness in the range of 5-45 nm leads to a more sustained release by decreasing the release rate of the pesticide from PHSNs, showing that the shell thickness is one of the main controlling factors for the active agent release from such systems.

Delayed-Action Preparations↗

PubMed2006

Systematic mRNA analysis for the effect of MLH1 and MSH2 missense and silent mutations on aberrant splicing.

A substantial proportion of MLH1 and MSH2 gene mutations in hereditary nonpolyposis colon cancer syndrome (HNPCC) families are characterized by nucleotide substitutions, either within the coding sequence (missense or silent mutations) or in introns. The question of whether these mutations affect the normal function of encoding mismatch DNA repair proteins and thus lead to the predisposition to cancer is determinant in genetic testing. Recent studies have suggested that some nucleotide substitutions can induce aberrant splicing by disrupting cis-transcription elements such as exonic enhancers (ESEs). ESE disruption has been proposed to be the mechanism that underlies the presumed pathological missense mutations identified in HNPCC families. To investigate the prevalence of aberrant splicing resulting from nucleotide substitutions, and its relevance to predicted ESEs, we conducted a systematic RNA screening of a series of 60 patients who carried unrelated exonic or intronic mutations in MLH1 or MSH2 genes. Aberrant splicing was found in 15 cases, five of which were associated with exonic mutations. We evaluated the link between those splicing mutations and predicted putative ESEs by using the computational tools ESEfinder and RESCUE-ESE. Our study shows that the algorithm-based ESE prediction cannot be definitely correlated to experimental observations from RNA screening. By using minigene constructs and in vitro transcription assay, we demonstrated that nucleotide substitutions are the direct cause of the splicing defect. This is the first systematic screening for the effect of missense and silent mutations on splicing in HNPCC patients. The pathogenic splicing mutations identified in this study will contribute to the assessment of "unclassified variants" in genetic counseling. Our results also suggest that one must use caution when determining the pathogenic effect of a missense or silent mutation using ESE prediction algorithms. Analysis at the RNA level is therefore necessary.

Adaptor Proteins, Signal Transducing↗

PubMed2006

DNA degradation in nuclei of muscle cells followed by ischemic injury in a rabbit amputation model.

This study evaluated DNA degradation in nuclei of muscle cells during ischemia in a rabbit limb amputation model. Seven New Zealand rabbits were used. The left rear limb of the animal was amputated. The quadriceps femoris muscle was biopsied, as well as the rabbit carotid arteries. Half of the tissue samples were preserved at a cold temperature (2-4 degrees C), and the other half were kept at room temperature (25 degrees C, global ischemia). Immediately and 4, 8, 12, 16, and 24 h after amputation, muscle tissue samples were stained with the Feulgen reaction and analyzed by an image-analysis system to detect DNA contents in muscle cell nuclei. Samples from carotid arteries were examined with a transmission electron microscope. The results showed that the DNA content in muscle cell nuclei was slightly decreased at 4 and 8 h of global ischemia. At 12 h after global ischemia, the DNA content was found to be significantly decreased (80.03% of baseline). The DNA content dropped to 53.93% of baseline at 16 h of global ischemia. However, in the muscle that was preserved at cold temperature, the DNA contents were only slightly changed along with the ischemia time at 24 h. The DNA changes were confirmed by transmission electron microscopic observations. The present findings could provide evidence for the study of revascularization of ischemic muscle.

Amputation, Surgical↗

PubMed2006

Analysis of the clinical features of recurrent acute pancreatitis in China.

BACKGROUND: Since few systematic studies have focused on recurrent acute pancreatitis in China, we sought to investigate its clinical features, including etiological factors and relative frequency. METHODS: Patients were selected from a total 1471 patients with acute pancreatitis in ten cities of China. All had been admitted to a hospital with an attack of acute pancreatitis between January 1992 and December 2002. Data for each patient was recorded on a standardized form. RESULTS: Of the 1471 patients with acute pancreatitis, 157 (10.7%) had recurrent acute pancreatitis. The majority (63%) were male, with a mean age of 41 years (range, 13-82 years). Regarding the etiology, alcohol (20.4%) and cholelithiasis (20.4%) were the most frequent causes, followed by diet (13.4%), hypertriglyceridemia (8.3%), biliary tract infection (5.7%), other (5.1%), and idiopathic factors (26.8%). Alcohol was most frequent in male patients (30.3%), whereas cholelithiasis was most frequent (34.5%) in female patients. The majority of patients (79.6%) presented with their second attack of pancreatitis. Complications of recurrent acute pancreatitis in order of frequency were pancreatic pseudocyst, multiple organ failure, diabetes mellitus type 2, and shock. CONCLUSIONS: Recurrent acute pancreatitis remains a frequent disease, with cholelithiasis and alcohol being the most usual etiological factors. Alcohol is the primary etiological factor in male patients. In about 26.8% of cases, the etiology remains unknown.

Acute Disease↗

PubMed2006

Mutational targets in colorectal cancer cells with microsatellite instability.

Cancers arise from the sequential acquisition of genetic alterations in specific genes. The high number of mutations in cancer cells led to the hypothesis that an early step in tumor progression is the generation of a genetic instability. The potent role of genetic instability in initiation and progression of colorectal cancers has been well defined in hereditary nonpolyposis colon cancer (HNPCC) syndrome. HNPCC is a common hereditary disorder caused by germline mutations of DNA mismatch repair (MMR) genes. Somatic loss of the normal allele of the predisposition gene leads to a strong "mutator phenotype", characterized by a high rate of mutations in repetitive sequences. Nevertheless, the observation of frequent alterations of key growth regulatory genes in MMR-deficient cells such as NF1, APC, p53, K-Ras, with no significant excess of frameshift mutations and changes at short coding repeats, suggest that even in the presence of an inherited tendency to genomic instability, tumor progression is mainly driven by a process of natural selection.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Preparation of hollow hydroxyapatite microspheres.

The preparation of hollow hydroxyapatite (HA) microspheres as potential drug-delivery vehicles was investigated. A lithium-calcium-borate (10Li(2)O-15CaO-75B(2)O(3)) (mol%) glass, made by fusing the components at 1100 degrees C for 1 h, was ground to a powder and passed through a flame at approximately 1400 degrees Celsius to spheroidize the particles. The resulting glass microspheres (106-125 microm in diameter) were reacted in 0.25 M K(2)HPO(4) solution for 5 days at 37 degrees Celsius and pH 10-12, resulting in the formation of porous, hollow microspheres of a calcium phosphate (Ca-P) material with external diameters similar to those of the original glass particles. Heat treatment at 600 degrees Celsius for 4 h partially converted the Ca-P material to HA, as confirmed by X-ray diffraction, and also increased the strength of the hollow microspheres.

Borates↗

PubMed2006

Genetic analysis of a family with 46,XY "female" associated with infertility.

Genetic analysis of a family with 46,XY "female" associated with infertility was performed using the conventional G-banding and gene mutation screening. The karyotypes of the two female patients were 46,XY and those of their parents were normal. The mutation screenings in sex-determining region Y (SRY) gene and androgen receptor (AR) gene were carried out. No mutation has been found in the whole coding sequence of SRY gene. The mutation of codon 840 CGT (arginine) to CAT (histidine) of AR gene led to the infertility in the patients. The patients showed androgen insensitivity. The clinical phenotype of theirs presented more deleteriously than and different from the one reported before, though they had the same mutation of codon 840 CGT (arginine) to CAT (histidine) of AR gene, which was very different from the mutation of 840 CGT (arginine) to TGT (cysteine) at the same codon.

Adolescent↗

PubMed2006

Mutation p.Arg954Trp of KIF21A causes congenital fibrosis of the extraocular muscles in a Chinese family.

Congenital fibrosis of the extraocular muscles type 1 (CFEOM1) is an autosomal dominant strabismus disorder associated with defects of the oculomotor nerve. In this study, we identified a Chinese family with CFEOMI for four generations. Linkage analysis mapped the causative gene of the family to 12q with a Lod score 2.1 for polymorphic marker D12S85, where KIF21A is located. Direct DNA sequence analysis identified a 2860C-->T change in exon 21, resulting in a tryptophan substitution for arginine in codon 954 of KIF21A. SSCP (single-stranded conformational polymorphism) analysis showed that mutation p.Arg954Trp of KIF21A co-segregated with the affected members, but was absent in the unaffected individuals in the family and 150 normal controls. Our results indicate that mutation p.Arg954Trp of the KIF21A is the genetic basis of the Chinese family with CFEOM1.

Amino Acid Substitution↗

PubMed2006

Dye-sensitized solar cells incorporating a "liquid" hole-transporting material.

We present the first application of an amorphous "liquid" organic semiconductor in an optoelectronic device, demonstrating that it is highly suited for use as a hole-transporting material in nanostructured dye-sensitized solar cells. For such devices, we obtain power conversion efficiencies of up to 2.4% under simulated air mass 1.5 solar spectrum at 100 mWcm(-2), and incident photon-to-electron quantum efficiencies in excess of 50%.

Coloring Agents↗

PubMed2006

An anthocyanin-rich extract from black rice enhances atherosclerotic plaque stabilization in apolipoprotein E-deficient mice.

Black rice and its pigment fraction may have antiatherogenic activity, but the exact component contributing to the beneficial effect remains unclear. The aim of the present study was to investigate the influence of the anthocyanin-rich extract from black rice on the vulnerability of advanced plaques in apolipoprotein (apo) E-deficient mice. Using LC-MS, the anthocyanin-rich extract from black rice was identified as containing cyanidin-3-glucoside and peonidin-3-glucoside. ApoE-deficient mice (n = 30; 30 wk old) were randomly divided into 3 groups: a control group (fed the AIN-93G diet), the simvastin group [simva; fed the AIN-93G diet containing simvastatin, 50 mg/(kg.d)], or the anthocyanin-rich extract group [antho; fed the AIN-93G diet supplemented with anthocyanin-rich extract from black rice, 300 mg/(kg.d)]. After 20 wk of intervention, the plaque area that developed in the brachiocephalic artery of mice in the antho group was smaller than that of the control mice. Both the antho and simva groups had lower frequencies of the large necrotic core and thin fibrous cap in plaques than the control group. Collagen I was increased and matrix metalloproteinase-1 contents were reduced in the brachiocephalic lesion of both the antho and simva groups compared with the control group. Furthermore, mRNA levels of tissue factor and inducible nitric oxide synthase in aortae were decreased in the antho and simva groups. Supplementation of anthocyanin-rich extract improved the lipid profile by decreasing serum triglyceride, total cholesterol, and non-HDL cholesterol. These results suggest that chronic diet intake of anthocyanin-rich extract from black rice may enhance plaque stabilization in old apoE-deficient mice. The underlying mechanism is related mainly to inhibiting proinflammatory factors and improving the serum lipid profile.

Animals↗

PubMed2006

Tumorigenesis suppressor Pdcd4 down-regulates mitogen-activated protein kinase kinase kinase kinase 1 expression to suppress colon carcinoma cell invasion.

Programmed cell death 4 (Pdcd4) suppresses neoplastic transformation by inhibiting the activation of c-Jun and consequently AP-1-dependent transcription. We report that Pdcd4 blocks c-Jun activation by inhibiting the expression of mitogen-activated protein kinase kinase kinase kinase 1 (MAP4K1)/hematopoietic progenitor kinase 1, a kinase upstream of Jun N-terminal kinase (JNK). cDNA microarray analysis of Pdcd4-overexpressing RKO human colon carcinoma cells revealed MAP4K1 as the sole target of Pdcd4 on the JNK activation pathway. Cotransfection of a MAP4K1 promoter-reporter with Pdcd4 demonstrated inhibition of transcription from the MAP4K1 promoter. Ectopic expression of Pdcd4 in metastatic RKO cells suppressed invasion. MAP4K1 activity is functionally significant in invasion, as overexpression of a dominant negative MAP4K1 (dnMAP4K1) mutant in RKO cells inhibited not only c-Jun activation but also invasion. Overexpression of a MAP4K1 cDNA in Pdcd4-transfected cells rescued the kinase activity of JNK. Thus, Pdcd4 suppresses tumor progression in human colon carcinoma cells by the novel mechanism of down-regulating MAP4K1 transcription, with consequent inhibition of c-Jun activation and AP-1-dependent transcription.

Apoptosis Regulatory Proteins↗

PubMed2006

Role of duodenogastroesophageal reflux in the pathogenesis of esophageal mucosal injury and gastroesophageal reflux symptoms.

BACKGROUND AND AIM: Patients with gastroesophageal reflux disease (GERD) usually suffer from acid reflux and duodenogastroesophageal reflux (DGER) simultaneously. The question of whether DGER has an important effect on the development of GERD remains controversial. The aim of the present study was to investigate the role of DGER in the pathogenesis of GERD and its value for the diagnosis of nonerosive reflux disease (NERD). METHODS: GERD was initially diagnosed using the reflux disease questionnaire. For further diagnosis, results of the upper gastrointestinal endoscopy (excluding a diagnosis of Barrett's esophagus) were considered in conjunction with simultaneous 24 h esophageal pH and bilirubin monitoring. RESULTS: According to endoscopic findings, 95 patients (43 men, 50+/-10 years of age) were divided into two groups: the reflux esophagitis (RE) group (n=51) and the NERD group (n=44). Three DGER parameters, the percentage of time with absorbance greater than 0.14, the total number of reflux episodes and the number of bile reflux episodes lasting longer than 5 min, were evaluated in the study. For the RE group, the values of the DGER parameters (19.05%+/-23.44%, 30.56+/-34.04 and 5.90+/-6.37, respectively) were significantly higher than those of the NERD group (7.26%+/-11.08%, 15.68+/-20.92 and 2.59+/-3.57, respectively, P<0.05 for all) but no significant difference was found in acid reflux. Of NERD patients, 18.5% were diagnosed with simple DGER. The positive diagnosis rate of NERD could be significantly elevated from 65.9% to 84.1% (P<0.05), if bilirubin monitoring was employed in diagnosis. CONCLUSIONS: DGER may occur independently but plays an important role in the development of RE and GERD symptoms. Simultaneous 24 h esophageal pH and bilirubin monitoring is superior to simple pH monitoring in helping identify patients at risk for NERD.

Adult↗

PubMed2006

[Scanning electron microscopic study on the use of traditional Chinese medical irrigant in ultrasonic root canal instrumentation].

PURPOSE: To evaluate the cleaning ability of traditional Chinese medicine Jieeryin used as ultrasonic root canal irrigant. METHODS: A total of 20 extracted human single-rooted teeth were divided into 4 groups: normal saline, 3.33% Jieeryin, 30% Jieeryin and 2.5% sodium hypochlorite. After ultrasonic root canal preparation a 15#-K type ultrasonic file was inserted into the root canal without contacting the root canal wall and the ultrasonic irrigation was kept for 10 seconds. The cleaning of the cervical, middle and apical thirds of the root canal walls was evaluated by scanning electron microscope. The data were analyzed statistically by ANOVA and Bonferroni test. RESULTS: The cleaning ability of 30% Jieeryin was similar to that of 2.5% NaClO (P>0.05) in the cervical third, and it was significantly better than 3.33% Jieeryin (P<0.01) and normal saline (P<0.05). There was significant difference between the cervical third and the middle or apical thirds (P<0.01) of 30% Jieeryin. There was no significant difference between the four groups in the middle third (P>0.05). In the apical third, 2.5% NaClO was significantly better than normal saline (P>0.05). No significant difference was found between 3.33% Jieeryin and saline in all thirds. CONCLUSION: Cleaning by 30% Jieeryin or 2.5% NaClO with ultrasonic technique was superior compared to the cleaning by 3.33% Jieeryin or normal saline in the cervical third.

Dental Pulp Cavity↗

PubMed2006

[Recombinant Aspergillus niger glucose oxidase expressed in Trichoderma reesei].

It was expected that recombinant Aspergillus niger glucose oxidase could be expressed in Trichoderma reesei with stable activity. T. reesei CBHI promoter--CBHI ss. gene--A. niger glucose oxidase gene--T. reesei CBHI terminator--A. nidulans gpd promoter--E. coli Hygromycin B phosphotransferase gene--A. nidulans trpC terminator--pUC19 (pCBHGOD) vector was constructed in E. coli DH5alpha by PCR application and gene cloning methods. T. reesei QM9414 protoplast was transformed by T. reesei CBHI promoter-CBHI ss. Gene--A. niger glucose oxidase gene--T. reesei CBHI terminator-A. nidulans gpd promoter--E. coli Hygromycin B phosphotransferase gene--A. nidulans trpC terminator linear DNA fragment (CBHGOD fragment) that was made by digestion of pCBHGOD with Kpn I. T. reesei mutant clone with homologous recombinant A. niger glucose oxidase gene was selected by PCR method. Recombinant glucose oxidase was produced by mutant T. reesei strain under induction of wheat straw for 5 days. Recombinant glucose oxidase molecular mass was showed the same as native A. niger glucose oxidase standard from Sigma company by Western blot analysis. Recombinant glucose oxidase activity was 25u/mL in medium. The yield was 0.5 g/L in comparison with Sigma company glucose oxidase standard. There was no recombinant GOD degradation during Trichoderma reesei cultivation that was showed in Western blot analysis. Trichoderma reesei has capability to be a new recombinant host for Aspergillus niger GOD production.

Aspergillus niger↗

PubMed2006

Two novel missense mutations of GATA4 gene in Chinese patients with sporadic congenital heart defects.

OBJECTIVE: To identify mutations in GATA4 gene in Chinese patients with sporadic congenital heart defects (CHD). METHODS: Single stranded conformation polymorphism (SSCP) analysis was performed to screen for mutations in all six exons and exon-intron boundaries of GATA4 in 31 individuals with CHD. Direct DNA sequencing was used to identify the specific mutations. RESULTS: Two novel missense mutations, V267M in exon 4, V380M in exon 6, and one polymorphism in intron 6 of GATA4 were identified. CONCLUSION: The above identified two novel GATA4 mutations associated with CHD in Chinese patients. This suggests that the transcription factor GATA4 may play an important role in cardiogenesis.

Adolescent↗

PubMed2006

[Analysis of publication of West China Journal of Stomatology from 2000 to 2005].

OBJECTIVE: To analyze the characteristic of publication of West China Journal of Stomatology (WCJS). METHODS: Making use of literature metrology, a comprehensive analysis of the information publication of West China Journal of Stomatology from 2000 to 2005 was made. RESULTS: The quantity of articles published from 2000 to 2005 in West China Journal of Stomatology was 964, the average fund paper ratio was 0.419, 96.78% of articles had more than one author, and the average paper author cooperating degree was 4.01. The authors scattered in 31 provinces. CONCLUSION: West China Journal of Stomatology is one of the most important information source of stomatology.

Bibliometrics↗

PubMed2006

[Relationship between paraoxonase 1 55 Met/Leu, paraoxonase 2 148 Ala/Gly genetic polymorphisms and coronary artery disease].

OBJECTIVE: To study the relationships between paraoxonase 1 55 Met/Leu (PON1 55Met/Leu), paraoxonase 2 148 Ala/Gly(PON2 148Ala/Gly) genetic polymorphisms and coronary artery disease(CAD), plasma activities of paraoxonase (PON), total superoxide dismutase (T-SOD), as well as plasma concentration of maleic dialdehyde (MDA). METHODS: The PCR-RFLP method was applied to identify the genetic polymorphisms of PON1 55Met/Leu and PON2 148Ala/Gly, and the colorimetry way was used to detect plasma activities of PON, T-SOD and plasma MDA concentration of 262 CAD patients and 100 controls. RESULTS: Comparing with control, the CAD patient had the obviously lower activities of enzymes PON (349.27+/- 138.36 nmol/min.mL vs 454.75+/- 166.00 nmol/min.mL, P< 0.001) and T-SOD (23.61+/- 16.51 U/mL vs 44.01+/- 22.68 U/mL, P< 0.001) while getting the plasma MDA concentration increased markedly(2.47+/- 0.73 nmol/mL vs2.15+/- 0.55 nmol/mL, P< 0.01). The CAD patient had more LM genotype and M allele of PON1 55Met/Leu(24.8% vs 1.4%, P< 0.001 and 12.4% vs 0.5%, P was 0.001 respectively), GG and AG genotype and G allele of PON2 148 Ala/Gly(11.8% vs 5.0%, P< 0.001; 48.1% vs 24.0%, P< 0.001 and 36.0% vs 17.0%, P< 0.001 respectively) than control did. The activities of plasma PON and T-SOD were lower in individuals with PON??1 55 LM genotype than those with LL genotype(304.73+/- 125.04 vs 394.84+/- 154.87 nmol/min.mL and 24.89+/- 16.14 vs 30.22+/- 21.29 U/mL, P< 0.001 and P< 0.05 respectively). The activity of plasma PON was also lower in individuals with PON2 148 GG/AG genotype than that with AA genotype(281.47+/- 84.70 vs 356.00+/- 145.95 vs 417.34+/- 159.00 nmol/min.mL, P< 0.001). Logistic regression analysis showed that PON1 55 LM genotype (OR 29.08, 95%CI 2.88-294.04, P was 0.004) and M allele(OR 15.17, 95%CI 1.32-174.29, P was 0.029), PON2 148 GG/AG genotype (OR 2.32, 95%CI 1.52-3.54, P< 0. 001) and G allele (OR 3.24, 95%CI 1.38-7.61, P was 0.007) were independent risk factors for CAD. CONCLUSION: The CAD patient has the obviously low activities of plasma PON and T-SOD but on the contrary, get the plasma MDA concentration increased markedly. PON1 55 LM genotype and M allele, PON2 148 GG/AG genotype and G allele are the risk factors for coronary artery disease, and the activity of plasma PON is also markedly reduced in individuals with above genotypes.

Adult↗