Biomedical subjects

H Yue

Publications and source records attributed to H Yue.

13 recordsLinked to original sources

PubMed2001

An evaluation of the performance of cDNA microarrays for detecting changes in global mRNA expression.

The cDNA microarray is one technological approach that has the potential to accurately measure changes in global mRNA expression levels. We report an assessment of an optimized cDNA microarray platform to generate accurate, precise and reliable data consistent with the objective of using microarrays as an acquisition platform to populate gene expression databases. The study design consisted of two independent evaluations with 70 arrays from two different manufactured lots and used three human tissue sources as samples: placenta, brain and heart. Overall signal response was linear over three orders of magnitude and the sensitivity for any element was estimated to be 2 pg mRNA. The calculated coefficient of variation for differential expression for all non-differentiated elements was 12-14% across the entire signal range and did not vary with array batch or tissue source. The minimum detectable fold change for differential expression was 1.4. Accuracy, in terms of bias (observed minus expected differential expression ratio), was less than 1 part in 10 000 for all non-differentiated elements. The results presented in this report demonstrate the reproducible performance of the cDNA microarray technology platform and the methods provide a useful framework for evaluating other technologies that monitor changes in global mRNA expression.

Analysis of Variance↗

PubMed2001

Optimized T7 amplification system for microarray analysis.

Glass cDNA microarray technologies offer a highly parallel approach for profiling expressed gene sequences in disease-relevant tissues. However, standard hybridization and detection protocols are insufficient for milligram quantities of tissue, such as those derived from needle biopsies. Amplification systems utilizing T7 RNA polymerase can provide multiple cRNA copies from mRNA transcripts, permitting microarray studies with reduced sample inputs. Here, we describe an optimized T7-based amplification system for microarray analysis that yields between 200- and 700-fold amplification. This system was evaluated with both mRNA and total RNA samples and provided microarray sensitivity and precision that are comparable to our standard production process without amplification. The size distributions of amplified cRNA ranged from 200 bp to 4 kb and were similar to original mRNA profiles. These amplified cRNA samples were fluorescently labeled by reverse transcription and hybridized to microarrays comprising approximately 10,000 cDNA targets using a dual-channel format. Replicate hybridization experiments were conducted with the same and different tissues in each channel to assess the sensitivity and precision of differential expression ratios. Statistical analysis of differential expression ratios showed the lower limit of detection to be about 2-fold within and between amplified data sets, and about 3-fold when comparing amplified data to unamplified data (99.5% confidence).

Biotechnology↗

PubMed2001

[Fingerprints of Radix Salviae Miltiorrhizae].

OBJECTIVES: To establish fingerprints of the Radix Salviae Miltiorrhizae from Shangluo Dansben Base of Tasly Group Co. Ltd., and to compare the fingerprints with fingerprints of Radix Salviae Miltiorrhizae from Tianjin market of medicinal materials. METHOD: By HPLC to establish fingerprint of water-soluble extract of Radix Salviae Miltiorrhizae. CONCLUSION: The fingerprints of 10 batches of Radix Salviae Miltiorrhizae from Shangluo conformed to the requirements of fingerprints of Chinese medicinal materials issued by State Drug Administration in 2000. And there were obvious differences between the fingerprints of Radix Salviae Miltiorrhizae from Shangluo and from Tianjin market of medicinal materials.

Chromatography, High Pressure Liquid↗

PubMed2001

[Expression significance of P21WAF1/CIP1 protein in eye-lid primary malignant tumor].

PURPOSE: To study the expression of P21waf1/cip1 protein in eye-lip primary malignant tumor (E-LPMT). METHODS: Immunohistochemical streptavidin biotin peroxidase complex(SP) method was used to stain section of E-LPMT. RESULTS: In 61 cases of E-LPMT, positive expression of P21waf1/cip1 protein was found locating in the nuclei. In Cell carcinoma, Squamous and Adenocarcinomas, the positive rate of P21waf1/cip1 protein expression were 36.0%, 27.8% and 22.2% respectively. The positive rate of P21waf1/cip1 protein expression in well-differentiated Cell carcinomas or Adenocarcinomas was higher than in poor-differentiated ones (P < 0.01). CONCLUSION: P21waf1/cip1 protein expresses in various type of E-IPMT and its positive expression in Cell carainomas and Adenocarcinomas are related to their different degrees.

Adenocarcinoma↗

PubMed2000

Accessory protein facilitated CFTR-CFTR interaction, a molecular mechanism to potentiate the chloride channel activity.

The cystic fibrosis transmembrane conductance regulator (CFTR) gene encodes a chloride channel protein that belongs to the superfamily of ATP binding cassette (ABC) transporters. Phosphorylation by protein kinase A in the presence of ATP activates the CFTR-mediated chloride conductance of the apical membranes. We have identified a novel hydrophilic CFTR binding protein, CAP70, which is also concentrated on the apical surfaces. CAP70 consists of four PDZ domains, three of which are capable of binding to the CFTR C terminus. Linking at least two CFTR molecules via cytoplasmic C-terminal binding by either multivalent CAP70 or a bivalent monoclonal antibody potentiates the CFTR chloride channel activity. Thus, the CFTR channel can be switched to a more active conducting state via a modification of intermolecular CFTR-CFTR contact that is enhanced by an accessory protein.

Amino Acid Sequence↗

PubMed2000

The two halves of CFTR form a dual-pore ion channel.

The cystic fibrosis transmembrane conductance regulator (CFTR) exhibits two conductance states, 9 picosiemens (pS) and 3 pS. To investigate the origin of these two distinct conductance states, we measured the single-channel activity of three truncated forms of CFTR. These include: TNR, which contains the first transmembrane domain, the first nucleotide binding domain, and the R domain; RT2N2, which contains the R domain, the second transmembrane domain, and the second nucleotide-binding domain; and T2N2, which contains only the second transmembrane domain and the second nucleotide-binding domain. The results show that TNR exhibits only the large conductance of 9.2 pS, whereas RT2N2 and T2N2 exhibit only the small conductance (3.8-4.0 pS). Co-expression of TNR with T2N2 resulted in a mixed pattern of two conductance states, which is similar to that observed in wild-type CFTR. In further studies, a "dual-R mutant," R334W and R347P in the transmembrane segment 6 of the first half of CFTR, severely impaired the large conductance channel without affecting the small conductance channel. The ion selectivity and gating behavior of the two conductance channels are different regardless of whether they are measured in wild-type CFTR or in truncated CFTRs. The ion selectivity of the large conductance channel is Br(-) > Cl(-) > I(-), whereas the ion selectivity of the small conductance channel is Br(-) = Cl(-) = I(-). The open probability (P(o)) of the large conductance is about 4-fold higher than that of the small conductance. Transition from closed to open states of the small conductance is not dependent upon the open or closed states of the large conductance. The independent behaviors of the two conductances in CFTR strongly suggest that CFTR may have two distinct pores. Thus, like ClC0, CFTR is likely to be a double-barreled ion channel, with the first half of CFTR forming the large conductance and the second half forming the small conductance.

Adenosine Triphosphate↗

PubMed2000

Surface- and optical-field-induced Freedericksz transitions and hysteresis in a nematic cell

For a homeotropic nematic liquid-crystal cell, this paper explores the influence of the surface anchoring and the cell thickness on the first-order optically induced Freedericksz transitions. The exact criteria for the existence of the first-order transitions at the threshold and at the saturation, respectively, are obtained in terms of material and device parameters for arbitrary anchoring conditions. The critical cell thickness, when thinner than which the first-order transitions will exist, is obtained. A standard for estimating the strength of the first-order transitions is proposed. The group equations for determining the tricritical points are listed. The factors, especially the nonmaterial factors to enhance the first-order transitions are discussed at length.

Journal Article↗

PubMed1999

[Development of healthy beverage from Eucommla ulmoides foliage].

Effective compositions of Eucommla ulmoides foliage, sampled from the south side west section of the Qinling Mountain area, are analyzed qualiatively and quantitatively. It is shown that the foliage contains plenty of mineral elements, seventeen amino acids, proteins, sugars, alkaloids, flavonoids, aucubin, chlorogenic acid, pinoresinol diglucoside, coffeic acid juice and Jingniping glucoside. Based on the analysis and the main material of Eucommla ulmoides foliage, a healthy beverage functioning especially on resisting tire actions is formulated and produced. This work has provided a dependable new idea for further exploitation and utilization of the natural resources.

Amino Acids↗

PubMed1998

The second half of the cystic fibrosis transmembrane conductance regulator forms a functional chloride channel.

The cystic fibrosis transmembrane conductance regulator (CFTR) consists of two transmembrane domains (TMDs), TMD1 and TMD2, two cytoplasmic nucleotide binding domains (NBDs), NBD1 and NBD2, and a regulatory domain. To elucidate the complex function of the CFTR, deletion constructs encompassing the second half of the CFTR distal to the first transmembrane domain were expressed in Xenopus oocytes and IB3 cells (a cystic fibrosis cell line). Constructs containing the regulatory domain, the second transmembrane domain, and the second nucleotide binding domain formed constitutively active channels, which were further stimulated upon the addition of cAMP. On the other hand, a construct encompassing the second transmembrane domain and the second nucleotide binding domain was stimulated to a small but noticeable extent upon the addition of cAMP. The selectivity of the second-half construct was the same for iodide and chloride, in contrast to the selectivity of wild-type CFTR, which is Cl- > I-. However, both constructs displayed single-channel conductances that were significantly smaller than those displayed by the first half of the CFTR. We conclude that regions of the second transmembrane domain may contribute to the overall channel of the pore, although the first half of the CFTR may confer its selectivity.

Animals↗

PubMed1998

Effects of isovolumetric hemodilution treatment and superoxide dismutase on ischemic reperfused hearts in rabbit.

UNLABELLED: The isovolumetric hemodilution treatment reduces ischemic injury and anti-radical interventions may reduce reperfusion injury. However, the effects of the treatment with both interventions have never been investigated. In the present study, anesthetized rabbits underwent 45 min of coronary artery ligation, which was followed by 180 min of reperfusion. Ten animals in each group received: (i) normal saline only; (ii) isovolumetric hemodilution with Dextran 40 during ischemia; (iii) superoxide dismutase (SOD) 1 min before and during reperfusion; and (iv) combined treatment with hemodilution and SOD. RESULTS: (1) compared with those of the control group, left ventricular peak pressure (LVP) and +/- dp/dt-max improved significantly in the animals which received hemodilution or SOD alone, and left ventricular systolic function of the animals with the combination therapy improved further; (2) infarct size averaged 54.4 +/- 2.6% of the risk region in controls and was significantly smaller in the rabbits that were treated with hemodilution (32.8 +/- 1.8%) (p < 0.05), with SOD (42.1 +/- 3.2%) (p < 0.05) and with the combination therapy (23.4 +/- 1.5%) (p < 0.01). Therefore, (1) in groups where either hemodilution during ischemia or removal of oxygen radicals during reperfusion was done left ventricular systolic function and salvaged ischemic reperfused myocardium improved significantly; (2) in this acute model, SOD improved left ventricular systolic and diastolic functions and reduced infarct size further when given to the animals that had been treated with hemodilution.

Animals↗

PubMed1997

The relationship between the vas volume and the anatomic size of the vas deferens.

The anatomic sizes of 210 vas segments from 107 volunteers of vasectomy were measured by computerized image graphic technique with microphotography. The mean equivalent-round, outer and inner diameters of the vas were 2.17 +/- 0.20 mm and 0.56 +/- 0.08 mm, respectively. The calculated thickness of vas wall was 0.81 +/- 0.21 mm. The maximal volumes of 124 vas segments (1 cm in length) were tested by injecting colored solution into vas lumen until vas rupture. The mean rupture volume of 1 cm vas lumen was 0.05 +/- 0.007 mL. A significant influence of the thickness of vas wall (p < 0.05) and body height (p < 0.05) on the rupture volume was noticed in stepwise regression analysis. A tunnel-like rupturing pattern was observed in morphological observation. The obtained rupture volume provides a security line in determining the injection volume of occlusive material or the size of the implanted contraceptive device.

Adult↗

PubMed1997

A dynamic frailty model for multivariate survival data.

We consider the statistical modeling of data consisting of many study subjects with serially correlated multivariate survival responses. The (ordinary) frailty model handles the serial correlation in such data by introducing an unobserved multiplicative random effect term, called the frailty, in the hazard function. The frailties are often assumed to be identical for the survival times from the same unit. We have generalized the frailty model by allowing the frailties to vary stochastically with the indices. We have proposed a simple scheme to update the dynamic frailties. This approach assumes that the random effects are gamma distributed. At each occurrence, the two gamma parameters are updated according to the past information. In terms of their marginal distributions, the dynamic frailties form a multiplicative random walk. This approach results in a tractable likelihood. The small sample behavior of the MLE is studied via a simulation experiment. The model is then illustrated with a data set from an animal carcinogenesis experiment.

Biometry↗

PubMed1990

[Screening of alpha-amino acid ester hydrolase producing strain and synthesis of cephalexin by Pseudomonas aeruginosa].

From ten genera and 146 bacterial strains, 22 strains producing alpha-amino acid ester hydrolase were selected. Among them, AS 1.586 and 41-2 were the best. The optimal conditions for synthesis of cephalexin by pseudomonas aeruginosa 1.204 were investigated. The optimal pH and temperature for enzymatic synthesis reaction was pH 6.8 and 25 degrees C, respectively. By using 1% 7-ADCA, 3% PGME and 4% biomass, about 70% of 7-ADCA was converted to cephalexin under the mentioned conditions.

Carboxylic Ester Hydrolases↗