Biomedical subjects

Ying Chen

Publications and source records attributed to Ying Chen.

At least 217 records · Page 12Linked to original sources

PubMed2004

[Dynamical analysis of the nonlinearity in the model of acute myocardial ischemia].

By analyzing the electrocardiosignals, many scholars have found remarkable and outstanding dynamic characteristics in both normal hearts and sick hearts. Based on those findings, a model of acute myocardial ischemia of six rabbits is designed by us and is presented here. The electrocardiogram (ECG) signals of different time series are calculated, and the figures of correlation dimensions-time and the maximum Lyapunov exponents-time are given. The results show that the existence of myocardial ischemia will bring the decline of the value of maximum Lyapunov exponents and correlation dimensions, after the figures being analyzed with electrophysiological and anatomical knowledge. The maximum Lyapunov exponents of ECG demonstrate the chaotic quality of the system and the correlation dimension of ECG demonstrates the complexity of the system, and there is no explicit relation between them. Correlation dimensions of ECG signals might be more influenced by partial heart system, compared with the maximum Lyapunov exponents of ECG signals.

Animals↗

PubMed2004

[Effect of gamma-interferon on protein expressions of interleukin-4 and transforming growth factor-beta1 in experimental silicotic rats].

OBJECTIVE: To study the effect of gamma-interferon on the protein expressions of interleukin-4 (IL-4) and transforming growth factor-beta(1)(TGF-beta1) on silicotic rats. METHODS: Wistar rats were exposed to lower dose (20 mg) of quartz by intratracheal injection. Next day, the experimental rats were treated with gamma-interferon (1 x 10(5) IU) daily. Rats were killed in 1 month and 2 month to observe the changes of pathology of lung tissue by use of HE and VG staining, and the expressions of IL-4 and TGF-beta1 by use of immunohistochemical technique and quantitative analysis of protein expressions by image analysis system. RESULTS: (1) The fibrotic degree in silicotic lesions of rat lung was 1/2 approximately 1 grade less in IFN-gamma treated groups than in quartz controls. (2) Quantitative image analysis showed that the integrated optical density (IOD) of IL-4 positive cell in quartz controls in 1 month was (3.33 +/- 1.27) x 10(4) and decreased to (1.99 +/- 0.80) x 10(4) in 2 month, and that of TGF-beta1 positive cell increased from (3.67 +/- 0.63) x 10(4) to (4.90 +/- 1.11) x 10(4); The IOD of IL-4 positive cell in IFN-gamma treated groups was decreased from (2.19 +/- 0.90) x 10(4) to (0.61 +/- 0.22) x 10(4)(P < 0.05), and that of TGF-beta1 positive cell increased from (1.37 +/- 0.31) x 10(4) to (1.76 +/- 0.72) x 10(4) (P < 0.05). At these two time points, the IODof IL-4 and TGF-beta1 positive cell in IFN-gamma treated groups were lower than those in quartz controls (P < 0.05 or P < 0.01). CONCLUSION: gamma-interferon may inhibit the expressions of IL-4 and TGF-beta1 in silicotic rats.

Animals↗

PubMed2004

[Preparation and evaluation in vivo and in vitro of glimepiride gel-matrix controlled-release patch].

AIM: To study the pharmaceutical characterization, the pharmacokinetics and relative bioavailability of glimepiride gel-matrix controlled-release patch in rats. METHODS: An HPLC method was established for the determination of glimepiride in the permeation receptor and patch. The permeation rate and penetration mechanism of glimepiride-TDDS through rabbit skin in vitro was examined. The determination of drug content and the examination of weight difference and stability of the glimepiride-TDDS were carried out. Another HPLC method after pre-column derivatization was developed to determine the glimepiride serum concentration and then employed to study the pharmacokinetics and relative bioavailability of glimepiride after a single dose of oral or patch administration in rats. RESULTS: The permeation tests through excised rabbit skin demonstrated that the optimized glimepiride controlled-release patch exhibited zero-order kinetic characteristics that satisfied the demands of original design. The determination of glimepiride content and the quality control of weight difference of the patch accorded with Pharmacopoeia of the People's Republic of China of 2000 edition and the pharmaceutical characterization showed good stability. The HPLC method for the determination of serum glimepiride was shown to be a sensitive and simple one. The pharmacokinetic results showed that TDDS could decrease the maximum serum concentration, prolong the peak time, extend the MRT by 5.5 times compared with oral administration and maintain the serum concentration of glimepiride at a higher level even after 120 h of administration. The relative bioavailability of glimepiride-TDDS was 20.3% versus oral administration. CONCLUSION: The glimepiride-TDDS showed a slower, longer and smoother serum concentration-time profile, as compared with conventional oral administration in both absorption and elimination phase. As a result, it was evident that the patch exhibited good controlled-release properties.

Administration, Cutaneous↗

PubMed2004

[Intravenous propofol combined with fentanyl for anesthesia during ultrasound-guided transvaginal oocyte retrieval].

OBJECTIVE: To compare the clinical efficacy and safety of anesthesia with intravenous propofol combined with fentanyl for ultrasound-guided transvaginal oocyte retrieval. METHODS: Totally 100 unpremedicated infertile women (ASA I-II) scheduled for oocyte retrieval with ultrasound guidance were randomly divided into two groups to receive anesthesia with either intravenous propofol (group A, n=50) or the combination of propofol and fentanyl (group B, n=50). The time when consciousness loss and recovery occurred, dosage of propofol for anesthesia maintenance, mean arterial blood pressure (MAP), heart rate (HR) and oxygen saturation (SpO2) were recorded. RESULTS: There was no significant difference in the time of consciousness loss between groups A and B (58.8+/-3.8 s vs 57.7+/-5.2 s, P=0.283), but consciousness recovery occurred earlier in group B (6.0+/-0.6 min vs 5.7+/-0.4 min, P<0.01). The maintenance dosage of propofol in group B (0.20+/-0.03 mg/kg) was significantly lower than that in group A (0.52+/-0.05 mg/kg, P<0.01). At 2 min after anesthesia induction, the MAP decreased from 11.1+/-0.8 kPa to 8.0+/-0.6 kPa in group A (P<0.05), and from (10.9+/-0.9) kPa to (8.3+/-0.7) kPa in group B(P<0.05), and returned to normal within 2-3 min in both groups. The incidence of low SpO2 (<90%) was lower in group A than in group B ((52% vs 88%, P<0.001). CONCLUSION: Anesthesia with propofol combined with fentanyl may reduce the maintenance dosage of propofol, shorten the time of consciousness recovery during oocyte retrieval with ultrasound guidance, and can be helpful for the patients' early recovery and discharge from hospital.

Adult↗

PubMed2004

[Analysis of sensorineural hearing loss in chronic suppurative otitis media].

OBJECTIVE: To explore the association between chronic suppurative otitis media and sensorineural hearing loss. METHOD: The files of 147 patients with unilateral chronic suppurative media were reviewed in a retrospective study. Differences between diseased and control ear bone conduction thresholds were analysed by the paired student's t-test over the four frequencies (0.5 kHz, 1.0 kHz, 2.0 kHz, 4.0 kHz). The effect of the presence of cholesteatoma and ossicular erosion on sensorineural hearing loss over the speech frequencies (0.5 kHz, 1.0 kHz, 2.0 kHz) and 4.0 kHz were analysed by one-way ANOVA. Linear regression models were used to clarify the relationships between sensorineural hearing loss and chronic suppurative otitis media. RESULT: The differences in bone conduction threshold between diseased and control ear were statistically significant. Bone conduction threshold shift at speech frequency was associated with the ages. The presence of cholesteatoma and ossicular erosion was not associated with a significantly increased risk of sensorineural hearing loss. CONCLUSION: Chronic suppurative otitis media can result in sensorineural hearing loss. The higher frequencies are easier affected than the lower frequencies.

Adolescent↗

PubMed2004

[Experimental hemorheology study on group a whole blood added with group O whole blood].

The study was to investigate the hemorheologyic changes of group A blood recipient transfused with large amounts of group O whole blood, by erythrocyte count, sympexis index, erythrocyte deformation index, erythrocyte rigid index and whole blood reduced viscosity, 60 ml of group A whole blood were added with 9, 12, 15 and 18 ml of group O whole blood (which corresponds to the 4 000 ml whole blood added with 600, 800, 1 000 and 1 200 ml whole blood). The mixed blood was incubated at 37 degrees C with mixing at 80 times per minute. Samples were taken from the mixed blood at 30 minutes, 2, 4, 8, 12 and 24 hours after culture, and the hemorheology of the mixed whole blood was determined by FASCO-series type 3020B automatic rheograph apparatus. The results showed that there were no differences of erythrocyte count, sympexis index, erythrocyte deformation index, erythrocyte rigid index and whole blood reduced viscosity among all different kinds of mixed whole blood, and there was no difference of sympexis index at different times, but there were obvious differences of erythrocyte count, erythrocyte deformation index, erythrocyte rigid index and whole blood reduced viscosity. It is concluded that blood transfusion of 1,200 ml group O whole blood to a recipient with 50 kg of body weight but with different blood type in emergent situation may exert no harm to the erythrocytes of recipient in a short term.

ABO Blood-Group System↗

PubMed2004

[Clinical and molecular research in a case of familial Carney complex].

OBJECTIVE: A case of primary pigmented nodular adrenal disease (PPNAD) was first diagnosed in Ruijin Hospital, Shanghai, China and molecular genetic research was then carried on the proband and his family members. METHODS: History and laboratory tests were routinely taken. Liddle's test, adrenal CT and pituitary magnetic resonance imaging were also carried out. Complete family history was obtained and eight of the family members donated their blood for DNA extraction. Polymerase chain reaction was done on all the exons of PRKAR1A gene and the product of the reaction was sequenced with ABI 3700. The right adrenal of the patient was then resected, part of the tissue was preserved in liquid nitrogen for DNA/RNA extraction and the remaining sent to Department of Pathology. RESULTS: The patient presented an atypical appearance of Cushing's syndrome. His father had a typical history of cardiac myoma. Cortisone level could not be refrained in Liddle's test for the patient. Imaging examination presented a nodular adrenal and a full pituitary. A novel mutation of PRKAR1A-S147N was found in both the patient's and his father's gene. CONCLUSIONS: This is the first patient diagnosed as PPNAD based on his clinical manifestations, laboratory tests and imaging and pathological examinations. According to the history of his father and the results of molecular genetic analysis, the diagnosis of Carney complex can be established on this patient and his father. It is also the first time that this kind of point mutation was found in Chinese people.

Adrenal Cortex Diseases↗

PubMed2004

[The impact of decreased Stat3 activation on 5-fluorouracil resistance of human gastric cancer cell line].

OBJECTIVE: To investigate the relationship between different activation of Stat3 signaling and the drug resistance mechanisms in two human gastric cancer cell lines, 5-fluorouracil (5-FU) resistant cell line and its parental cell line. METHODS: Electrophoretic mobility shift assay and Western blot were used to detected Stat3 DNA-binding activity and the expression of phospho-Stat3 protein in 5-FU resistant cell line SGC7901/R and its parental cell line SGC7901, respectively. The mRNA expression of Stat3 and vascular endothelial growth factor (VEGF) were analysed with semi-quantitative RT-PCR. The expressive intensity of VEGF protein was measured by immunocytochemistry. RESULTS: The constitutive activation of Stat3 and the expression of phospho-Stat3 protein were different in two human gastric cancer cell lines. Compared with the parental cell line SGC7901, the Stat3-DNA binding activity and the expressive intensity of phospho-Stat3 protein were lower in the drug-resistant cell line SGC7901/R. The expression level of Stat3 mRNA was also decreased in drug resistant cell line, so did VEGF mRNA and its encoded protein. CONCLUSIONS: The decreased Stat3 activation in 5-FU resistant human gastric cancer cell line SGC7901/R is related to the drug resistance mechanisms and may be correlated with the lower VEGF expression.

Antimetabolites, Antineoplastic↗

PubMed2004

[Effect of nutrient on sludge settling property and bulking controls].

The effect of nutrient (N and P) deficiency on activated sludge settleability and characteristics of activated sludge flocs in Sequencing Batch Reactor (SBR) fed with brewery wastewater were investigated. The results showed that the activated sludge had good settling properties at influent BOD5/N/P was 100/5/1,100/5/0.8 and 100/4/0.8 respectively. When BOD5/N/P was 100/0.94/0.31,100/2/0.4,100/3/0.6 respectively, the sludge settleability became worse due to excessive growth of filamentous. When BOD5/N/P was 100/0.94/1,100/5/0.31,100/5/0.4,100/5/0.6 respectively, non-filamentous activated sludge bulking occurred. Adding sufficient nutrient to the influent, the sludge bulking was controlled effectively and the low SVI was recovered. When increasing COD loading rate, the duration of recovery could be diminished. When nitrogen and phosphorus were insufficient synchronously, aerobic granular sludge was formed which was averagely 2mm-6mm in diameter.

Bacteria, Aerobic↗

PubMed2004

[The spectroscopic behaviour and extraction separation of Cu(II), La(III), U(VI) and Ce(IV) in two-phase aqueous systems].

In polyethylene glycol 2000 (PEG)-(NH4)2 SO4-extractant (sodium diethyldithiocarbamate, DDC) two-phase aqueous systems, spectroscopic behaviour of complexes of Cu(II), La(III), U(VI) and Ce(IV) with DDC as the extractant in PEG phase and general water phase was investigated. Comparing to DDC spectrophotometry, the new method has the advantage that the maximum wavelength of complex of Cu(II) shifts to red wavelength. Extraction mechanism and existing form of complexes of metal ions in PEG phase were studied. Effects of different acidity, quantities of DDC and salt, different surfactant on the extraction efficiency of copper(II), lanthanum(III), uranium(VI) and cerium(IV) were discussed. Experimental results show that Cu(II) was almost completely extracted in PEG phase at pH 5-8, U(VI) was partly extracted at pH 1-11, while La(III) and Ce(IV) were not extracted at pH 3-6 buffer solution. So, extraction separation of Cu(II)-La(III) and Cu(II)-Ce(IV) was carried out by controlling the solution acidity.

English Abstract↗

PubMed2003

Fluorescence losses from Yb:YAG slab lasers.

We report on the distribution of fluorescence that can be emitted through the surfaces of a ytterbium-doped yttrium aluminum garnet (Yb:YAG) slab-shaped high-power solid-state laser. Slab shapes considered include parallel or antiparallel Brewster endfaced slabs and rectangular parallelepiped slabs. We treat cases in which all the faces of these slabs are in air, or with water or another coating on the largest faces. The fraction of the fluorescence emitted through each face, its distribution over that face, and the directions in which it travels are shown to be important to the design of high-power slab lasers.

Journal Article↗

PubMed2003

Parallel detection of autoantibodies with microarrays in rheumatoid diseases.

BACKGROUND: Clinical needs often dictate testing for several autoantibodies in a single patient with evidence of autoimmune disease. We developed a microarray containing 15 autoantigens for the detection of autoantibodies in rheumatoid autoimmune diseases. METHODS: We synthesized recombinant centromere protein B, cytokeratin 19, SSA 52-kDa antigen, SSA 60-kDa antigen, SSB antigen, and Jo-1 antigen and prepared anti-nuclear antibody antigens. Cyclic citrullinated peptide, histone, goat IgG for detection of rheumatoid factor, double-stranded DNA, and single-stranded DNA were purchased, as were recombinant small nuclear ribonucleoprotein U1, topoisomerase I, and Smith antigen (Sm). All 15 antigens were of human origin except calf thymus Sm. Proteins were printed on polystyrene. The arrays were incubated with serum samples and then with horseradish peroxidase-conjugated secondary antibodies and chemiluminescent substrates, and light signals were captured by a charge-coupled device camera-based chip reader. Antibodies were quantified by use of calibration curves. Positive samples were confirmed by commercially available methods. RESULTS: The detection limit of the microarray system was 20 pg of IgG printed on the polystyrene support. More than 85% of the confirmed positive sera were detected as positive with the microarray system based on cutoff values established with the microarray system. The imprecision (CV) of the microarrays was <15% for all 15 autoantibody assays, with the exception of single-stranded DNA (18% and 23%) within and between batches. Characteristic autoantibody patterns were seen in patients with clinical diagnoses of rheumatoid arthritis (n = 83), systemic lupus erythematosus (n = 71), systemic sclerosis (n = 36), polymyositis (n = 38), and Sjogren syndrome (n = 20). CONCLUSIONS: This microarray system provides results similar to those by conventional methods. Assessment of the diagnostic accuracy of the system remains to be done.

Adolescent↗

PubMed2003

Inhibition of hepatitis B virus replication by stably expressed shRNA.

The major challenges for anti-hepatitis B Virus (HBV) therapy are the low efficacy of current drugs and the occurrence of drug resistant HBV mutations. A drug with new target sites or independent metabolic pathways may overcome these shortcomings. Small interfering RNA (siRNA) offers the possibility of developing a new anti-HBV therapy. Here we describe the almost complete inhibition of HBV replication by stably expressed 21-mer short hairpin RNAs (shRNA). Besides the conventional targets on HBV reverse-transcriptase, we also systemically targeted other sites of pregenomic RNA, including direct repeat (DR) elements, S, core, and X gene. Our results indicated that shRNAs can serve as efficient alternative anti-HBV agents. They can also be used in combination with chemotherapy, because they showed better effects on the inhibition of HBV replication due to different mechanisms of drug actions.

Carcinoma, Hepatocellular↗

PubMed2003

Diastereoselective and enantioselective cyclopropanation of alkenes catalyzed by cobalt porphyrins.

Cobalt(II) porphyrin complexes were shown to be general and efficient catalysts for selective cyclopropanation of alkenes with ethyl diazoacetate (EDA). The catalytic system can operate with alkenes as limiting reagents, requiring only stoichiometric amounts of EDA. The protocol is performed in one-pot fashion without the need of slow addition of EDA. The diastereoselectivity of the current system can be tuned by using different porphyrin ligands or additives, giving either trans- or cis-dominant cyclopropanes. The asymmetric cyclopropanation was also demonstrated with the use of chiral cobalt porphyrin complexes.

Journal Article↗

PubMed2003

Activin/Nodal signals mediate the ventral expression of myf-5 in Xenopus gastrula embryos.

Expression of myf-5, a key component of myogenic regulatory genes, expands into the ventral marginal zone during Xenopus gastrulation after the dorsal activation takes place. Little is known about how this dynamic expression pattern occurs. Here, we provide evidences to suggest that Activin/Nodal signals participate in the regulation of ventral expression of Xmyf-5 in gastrula embryos. Two Smad binding elements (SBEs) within the Xenopus myf-5 promoter can specifically interact with Smad4 protein. Furthermore, we demonstrate that the two SBEs are both indispensable for conferring responsiveness to Activin/Nodal signals and to ventral expression of myf-5 in Xenopus gastrula embryos.

Activins↗

PubMed2003

Immunoblot analysis and immunohistochemical characterization of CYP2A expression in human olfactory mucosa.

The aim of the present study was to further characterize the expression of the CYP2A genes in human nasal mucosa. Fetal nasal tissues at 12-26 weeks of gestational age and surgical biopsy tissues from various regions of nasal cavity of adult patients were studied to determine whether CYP2A proteins can be detected by immunoblot in adults, whether higher levels of CYP2A proteins are present in adult than in fetal nasal mucosal microsomes, and whether CYP2A13 mRNA is more abundant than CYP2A6 mRNA in fetal nasal mucosa. In adults, immunoblot analysis detected CYP2A proteins in microsomes of the olfactory region from 8 of 10 individuals, but in none of the nasal microsomes of the respiratory region from 47 patients. Quantitative immunoblot analysis confirmed that CYP2A proteins are selectively expressed in the olfactory region in both adult and fetal tissues. Interestingly, the levels of CYP2A proteins in nasal microsomes were generally higher in fetuses than in adults. In the fetus, the level of CYP2A13 mRNA was much higher than that of CYP2A6 mRNA, as has been previously found in adult nasal mucosa. Immunohistochemical studies confirmed that, in the fetus, the CYP2A proteins are expressed in the supporting cells in the olfactory epithelium and in the Bowman's glands in the lamina propria. The prenatal expression of the CYP2A proteins in the olfactory mucosa suggests potential risks of developmental toxicity from maternally derived xenobiotics, since both CYP2A6 and CYP2A13 are known to be efficient in the metabolic activation of tobacco-specific nitrosamines and other respiratory toxicants.

Aryl Hydrocarbon Hydroxylases↗

PubMed2003

Compensatory evolution of a precursor messenger RNA secondary structure in the Drosophila melanogaster Adh gene.

Evidence for the evolutionary maintenance of a hairpin structure possibly involved in intron processing had been found in intron 1 of the alcohol dehydrogenase gene (Adh) in diverse Drosophila species. In this study, the putative hairpin structure was evaluated systematically in Drosophila melanogaster by elimination of either side of the stem using site-directed mutagenesis. The effects of these mutations and the compensatory double mutant on intron splicing efficiency and ADH protein production were assayed in Drosophila melanogaster Schneider L2 cells and germ-line transformed adult flies. Mutations that disrupt the putative hairpin structure right upstream of the intron branch point were found to cause a significant reduction in both splicing efficiency and ADH protein production. In contrast, the compensatory double mutant that restores the putative hairpin structure was indistinguishable from the WT in both splicing efficiency and ADH level. It was also observed by mutational analysis that a more stable secondary structure (with a longer stem) in this intron decreases both splicing efficiency and ADH protein production. Implications for RNA secondary structure and intron evolution are discussed.

Alcohol Dehydrogenase↗

PubMed2003

Versatile synthesis of meso-aryloxy- and alkoxy-substituted porphyrins via palladium-catalyzed C-O cross-coupling reactions.

[reaction: see text] meso-Aryloxy- and alkoxy-substituted porphyrins were conveniently synthesized by direct reactions of meso-halogenated porphyrins with alcohols via palladium-catalyzed C-O cross-coupling reactions. Using a combination of palladium precursor Pd(OAc)(2) or Pd(2)(dba)(3) and phosphine ligand DPEphos or Xantphos allowed both 5-bromo-10,20-diarylporphyrin and 5,15-dibromo-10,20-diarylporphyrin, as well as their zinc complexes, to be effectively coupled with a variety of alcohols to give the corresponding mono- and bis-substituted meso-aryloxy/alkoxyporphyrins in moderate to high yields under mild conditions.

Journal Article↗