Biomedical subjects

X Cui

Publications and source records attributed to X Cui.

At least 55 records · Page 3Linked to original sources

PubMed2000

Multiplex genotype analysis of invasive carcinoma and accompanying proliferative lesions microdissected from breast tissue.

To understand the genetic basis of breast cancer in a comprehensive way, purported precursor lesions need to be analyzed at a large number of genetic marker loci and compared with each other and with the invasive components. However, the microscopic size of most of these lesions and the very small amount of material that can be obtained through microdissection limit the number of loci that can be included in the analysis. To address this issue, a multiplex genotyping approach has been developed. With this approach, polymorphic sequences at 28 marker loci were amplified simultaneously from the micro-dissected components in 5-microm paraffin-embedded breast tissue sections. The genotypes of the lesions were determined after resolving the amplified allelic products by denaturing gradient gel electrophoresis. Because the material isolated from each lesion in a single 5-microm section was sufficient for several 28-locus assays and several successive tissue sections with the same set of lesions may be prepared, it is possible to determine the genotype of each lesion at hundreds of genetic marker loci that may well cover the human genome. Analyzing a sufficient number of cases may yield information that could be used to understand the genetic basis of breast cancer development in a comprehensive way.

Alleles↗

PubMed2000

Gene delivery from a DNA controlled-release stent in porcine coronary arteries.

Expandable intra-arterial stents are widely used for treating coronary disease. We hypothesized that local gene delivery could be achieved with the controlled release of DNA from a polymer coating on an expandable stent. Our paper reports the first successful transfection in vivo using a DNA controlled-release stent. Green fluorescent protein (GFP) plasmid DNA within emulsion-coated stents was efficiently expressed in cell cultures (7.9% +/- 0.7% vs. 0.6% +/- 0.2% control, p < 0.001) of rat aortic smooth muscle cells. In a series of pig stent-angioplasty studies, GFP expression was observed in all coronary arteries (normal, nondiseased) in the DNA-treated group, but not in control arteries. GFP plasmid DNA in the arterial wall was confirmed by PCR, and GFP presence in the pig coronaries was confirmed by immunohistochemistry. Thus, DNA-eluting stents are capable of arterial transfection, and could be useful as delivery systems for candidate vectors for gene therapy of cardiovascular diseases.

Animals↗

PubMed2000

Human immunoglobulin VH4 sequences resolved by population-based analysis after enzymatic amplification and denaturing gradient gel electrophoresis.

Exhaustive gene identification followed by assignment of the genes identified to corresponding loci is a key step in elucidating the physical structure of a multigene family. However, problems occur in this process because genes in a multigene family usually share a high degree of sequence identity and are highly polymorphic. To address these problems, an efficient population-based approach was developed. Using this approach, sequences in the human immunoglobulin VH4 family were amplified by PCR with family-specific primers. Denaturing gradient gel electrophoresis (DGGE) was used to separate the resulting sequences with either very similar or identical sizes and differing by as little as 1 base pair (bp). Eighteen distinct bands and 21 banding patterns were observed in the samples collected from 41 unrelated individuals. Of the 18 bands, 12 were polymorphic. No sample had all 18 bands. The estimated frequencies for the alleles represented by the 18 bands ranged from 1.2 to 100%. The 18 sequences differed from each other by 1-19 bases (0.7 to 13%) within the 145-146-bp amplified region. Sequences in eight bands (44%) were not reported previously. These results were used to assign the majority (14 out of 18) of the VH4 sequences to 10 loci. This PCR-DGGE method, in conjunction with a population-based assay, may also be used to study other multigene families including those involved in the development of the immune system.

Base Sequence↗

PubMed2000

Reduced p21(WAF1/CIP1) protein expression is predominantly related to altered p53 in hepatocellular carcinomas.

To investigate the relationship between the expression of p21(WAF1/CIP1) protein and p53 status and the possible role of the two proteins in hepatocellular carcinomas (HCCs), we examined the expression of p21(WAF1/CIP1) and p53 immunohistochemically in 81 tumours from 65 patients with hepatocellular carcinoma. p21(WAF1/CIP1) protein was absent from 59 of 81 tumours (72.8%), and altered p53 expression was found in 43 (53.1%). p21(WAF1/CIP1) expression was significantly associated with p53 status (P = 0.0008); 38 of 59 tumours lacking p21(WAF1/CIP1) protein were accompanied by altered p53 expression. Further analyses showed that p21(WAF1/CIP1) expression was inversely correlated with p53 expression in hepatitis C virus (HCV)-related HCCs, but not in HBV-related hepatocellular carcinomas and hepatocellular carcinomas without viral infection. All 11 tumours with intrahepatic metastasis showed altered p21(WAF1/CIP1) or p53 expression. In contrast, no intrahepatic metastasis was found in any of the 17 tumours without abnormal expression of either of the two proteins. These results suggest that: (1) different modes of p21(WAF1/CIP1) regulation are involved in HCCs differing in their hepatitis viral infection status, and p21(WAF1/CIP1) expression appears to be predominantly related to altered p53 in HCV-related HCCs; (2) disruption of the p53-p21(WAF1/CIP1) cell-cycle-regulating pathway may contribute to malignant progression of HCC.

Adolescent↗

PubMed2000

Identification of a novel family of nonclassic yeast phosphatidylinositol transfer proteins whose function modulates phospholipase D activity and Sec14p-independent cell growth.

Yeast phosphatidylinositol transfer protein (Sec14p) is essential for Golgi function and cell viability. We now report a characterization of five yeast SFH (Sec Fourteen Homologue) proteins that share 24-65% primary sequence identity with Sec14p. We show that Sfh1p, which shares 64% primary sequence identity with Sec14p, is nonfunctional as a Sec14p in vivo or in vitro. Yet, SFH proteins sharing low primary sequence similarity with Sec14p (i.e., Sfh2p, Sfh3p, Sfh4p, and Sfh5p) represent novel phosphatidylinositol transfer proteins (PITPs) that exhibit phosphatidylinositol- but not phosphatidylcholine-transfer activity in vitro. Moreover, increased expression of Sfh2p, Sfh4p, or Sfh5p rescues sec14-associated growth and secretory defects in a phospholipase D (PLD)-sensitive manner. Several independent lines of evidence further demonstrate that SFH PITPs are collectively required for efficient activation of PLD in vegetative cells. These include a collective requirement for SFH proteins in Sec14p-independent cell growth and in optimal activation of PLD in Sec14p-deficient cells. Consistent with these findings, Sfh2p colocalizes with PLD in endosomal compartments. The data indicate that SFH gene products cooperate with "bypass-Sec14p" mutations and PLD in a complex interaction through which yeast can adapt to loss of the essential function of Sec14p. These findings expand the physiological repertoire of PITP function in yeast and provide the first in vivo demonstration of a role for specific PITPs in stimulating activation of PLD.

Base Sequence↗

PubMed2000

Set domain-dependent regulation of transcriptional silencing and growth control by SUV39H1, a mammalian ortholog of Drosophila Su(var)3-9.

Mammalian SET domain-containing proteins define a distinctive class of chromatin-associated factors that are targets for growth control signals and oncogenic activation. SUV39H1, a mammalian ortholog of Drosophila Su(var)3-9, contains both SET and chromo domains, signature motifs for proteins that contribute to epigenetic control of gene expression through effects on the regional organization of chromatin structure. In this report we demonstrate that SUV39H1 represses transcription in a transient transcriptional assay when tethered to DNA through the GAL4 DNA binding domain. Under these conditions, SUV39H1 displays features of a long-range repressor capable of acting over several kilobases to silence basal promoters. A possible role in chromatin-mediated gene silencing is supported by the localization of exogenously expressed SUV39H1 to nuclear bodies with morphologic features suggestive of heterochromatin in interphase cells. In addition, we show that SUV39H1 is phosphorylated specifically at the G(1)/S cell cycle transition and when forcibly expressed suppresses cell growth. Growth suppression as well as the ability of SUV39H1 to form nuclear bodies and silence transcription are antagonized by the oncogenic antiphosphatase Sbf1 that when hyperexpressed interacts with the SET domain and stabilizes the phosphorylated form of SUV39H1. These studies suggest a phosphorylation-dependent mechanism for regulating the chromatin organizing activity of a mammalian su(var) protein and implicate the SET domain as a gatekeeper motif that integrates upstream signaling pathways to epigenetic regulation and growth control.

3T3 Cells↗

PubMed2000

Effects of Lu-Duo-Wei capsules on superoxide dismutase activity and contents of malondialdehyde and lipofuscin in the brain of the housefly.

The biochemical actions of Lu-Duo-Wei capsules and tea polyphenol in relation to their antioxidant capability have been compared in the male housefly, Musca domestica. It was found that tea polyphenol had the effect of increasing the activity of superoxide dismutase (SOD) in the brain of the housefly only at the 60th day in the experimental period whereas Lu-Duo-Wei showed more obvious effects on SOD than tea polyphenol irrespective of experimental days. Moreover, the contents of malondialdehyde (MDA) and the rate of lipofuscin accumulation were decreased by the effect of Lu-Duo-Wei at the 20th, 40th, 50th and 60th days, while the similar effect of tea polyphenol on the content of MDA and lipofuscin was observed only at the 40th day. These results indicated that the biochemical actions of Lu-Duo-Wei in antiaging was much stronger than those of tea polyphenol, the mechanism of which was probably related to the synergistic effect of its involved antioxidants and others as well as the exclusive promotion of SOD biosynthesis/or a reduction of free radical-induced damage of the enzyme.

Analysis of Variance↗

PubMed2000

C-type natriuretic peptide inhibits ANP secretion and atrial dynamics in perfused atria: NPR-B-cGMP signaling.

The purpose of the present experiments was to define the role of C-type natriuretic peptide (CNP) in the regulation of atrial secretion of atrial natriuretic peptide (ANP) and atrial stroke volume. Experiments were performed in perfused beating and nonbeating quiescent atria, single atrial myocytes, and atrial membranes. CNP suppressed in a dose-related fashion the increase in atrial stroke volume and ANP secretion induced by atrial pacing. CNP caused a right shift in the positive relationships between changes in the secretion of ANP and atrial stroke volume or translocation of the extracellular fluid (ECF), which indicates the suppression of atrial myocytic release of ANP into the paracellular space. The effects of CNP on the secretion and contraction were mimicked by 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP). CNP increased cGMP production in the perfused atria, and the effects of CNP on the secretion of ANP and atrial dynamics were accentuated by pretreatment with an inhibitor of cGMP phosphodiesterase, zaprinast. An inhibitor of the biological natriuretic peptide receptor (NPR), HS-142-1, attenuated the effects of CNP. The suppression of ANP secretion by CNP and 8-BrcGMP was abolished by a depletion of extracellular Ca(2+) in nonbeating atria. Natriuretic peptides increased cGMP production in atrial membranes with a rank order of potency of CNP > BNP > ANP, and the effect was inhibited by HS-142-1. CNP and 8-BrcGMP increased intracellular Ca(2+) concentration transients in single atrial myocytes, and mRNAs for CNP and NPR-B were expressed in the rabbit atrium. From these results we conclude that atrial ANP release and stroke volume are controlled by CNP via NPR-B-cGMP mediated signaling, which may in turn act via regulation of intracellular Ca(2+).

Animals↗

PubMed2000

Distinct roles for L- and T-type Ca(2+) channels in regulation of atrial ANP release.

Atrial secretion of atrial natriuretic peptide (ANP) has been shown to be regulated by atrial workload. Although modulating factors for the secretion of ANP have been reported, the role for intracellular Ca(2+) on the secretion of ANP has been controversial. The purpose of the present study was to define roles for L- and T-type Ca(2+) channels in the regulation of ANP secretion in perfused beating rabbit atria. BAY K 8644 (BAY K) increased atrial stroke volume and pulse pressure. BAY K suppressed ANP secretion and ANP concentration in terms of extracellular fluid (ECF) translocation concomitantly with an increase in atrial dynamics. BAY K shifted the relationship between ANP secretion and ECF translocation downward and rightward. These results indicate that BAY K inhibits myocytic release of ANP. In the continuous presence of BAY K, diltiazem reversed the effects of BAY K. Diltiazem alone increased ANP secretion and ANP concentration along with a decrease in atrial dynamics. Diltiazem shifted relationships between ANP secretion and atrial stroke volume or ECF translocation leftward. The T-type Ca(2+) channel inhibitor mibefradil decreased atrial dynamics. Mibefradil inhibited ANP secretion and ANP concentration in contrast with the L-type Ca(2+) channel inhibitor. These results suggest that activation of L- and T-type Ca(2+) channels elicits opposite effects on atrial myocytic release of ANP.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed2000

Interferon-gamma stimulates the expression of CX3CL1/fractalkine in cultured human endothelial cells.

CX3CL1/Fractalkine, a CX3C chemokine, is a potent agonist for the chemotaxis and adhesion of monocytes and lymphocytes. It was first identified as a membrane protein in endothelial cells activated with IL-1 or TNF-alpha. We have found the enhanced expression of fractalkine in human umbilical vein endothelial cells stimulated with interferon-gamma (IFN-gamma). Pretreatment of the cells with cycloheximide did not inhibit the expression of fractalkine mRNA. The majority of fractalkine protein was found in the cell lysate, and an antibody-blocking experiment disclosed that fractalkine contributes to the adhesion of mononuclear cells to endothelial monolayers stimulated with IFN-gamma. Vascular endothelial cells produce fractalkine in response to IFN-gamma, and this may play an important role in immune responses by eliciting a traffic of mononuclear cells through the vascular wall.

Antibodies↗

PubMed2000

Xenotransplantation of microencapsulated bovine chromaffin cells into hemiparkinsonian monkeys.

This study examines the effects of xenografts of microencapsulated bovine chromaffin cells (BCCs) on the rotational behavior of hemiparkinsonian monkey recipients. In addition, it determines the content of monoamine neurotransmitters and their major metabolites in the neostriatum in hemiparkinsonian monkeys. The hemiparkinsonian model in monkeys was induced by a unilateral intracarotid injection of methyl-phenyl-tetrahydropyridine (MPTP). Unencapsulated BCCs, BCCs microencapsulated in alginate-polylysine-alginate (ALA) membranes as well as empty microencapsules were grafted into the neostriatum of the hemiparkinsonian monkeys. Following the transplantation the hemiparkinsonian symptoms subsided and the number of rotations induced by apomorphine decreased for up to nine months in the group of recipients grafted with microencapsulated BCCs, while only a temporary improvement (one month) was detected in the recipients of the unencapsulated BCCs. No change was observed in the recipients of empty microencapsules. Dopamine and its metabolites were found considerably depleted in the MPTP-lesioned side versus the unlesioned side of the neostriatum in the hemiparkinsonian monkeys(P<0.05).

3,4-Dihydroxyphenylacetic Acid↗

PubMed2000

[The in vivo degradation, adsorption and excretion of poly(epsilon-caprolactone)].

The in vivo degradation of poly(epsilon-caprolactone(PCL) was studied in rats. The results showed that the PCL capsules with an initial molecualr weight of 66,000 stayed intact in vivo for 2 years, although the molecular weight of the capsules gradually declined during the two-year implantation. It then degraded into low molecular wight pieces with the extension of the implantation. Tritium-labeled low molecular weight PCL was subcutaneously implanted in rats to further investigate the absorption and excretion of the material. The radioactivity was first detected in blood 15 days post the implantation. At the same time radioactive excreta were recovered from feces and urine. An accumulative 92% of the implanted radioactive dosage was excreted from feces and urine 135 days post the implantation. In the meanwhile, the blood radioactivity dropped to the background level. Radioactivity in the organs was all close to the background level indicating that the material did not cumulate in body tissue and could be completely excreted.

Absorption↗

PubMed2000

[CO2 release from typical Stipa grandis grassland soil].

Determinations on the soil respiration in a typical Stipa grandis grassland of Inner Mongolica by the method of static chamber/alkaline absorbing show that there existed great spatial and temporal variances of soil respiration, and the factors controlling these variances were different. The seasonal variance of soil respiration had a close relationship with the aboveground biomass of S. grandis and the status of soil moisture. The total amount of annual CO2 release in 1995, 1997 and 1998 was estimated as 180, 45.8 and 225 gC.m-2.yr-1, respectively. Overgrazing greatly decreased the biomass of the community, and also, decreased the CO2 release from the soil. The possibility of establishing a dynamic model of soil respiration in grassland with precipitation as a driven factor was discussed.

Biomass↗

PubMed2000

Relationship between metabolic phenotype of N-acetylation and bladder cancer.

OBJECTIVE: To study the relationship between metabolic phenotype of acetylation and bladder cancer. METHODS: Totally 203 healthy volunteers and 67 patients with bladder cancer were investigated with caffeine as a metabolic probe. Urine samples were collected in 2-6 hours after a cup of 140 mg coffee was taken, and the caffeine metabolites, 5-acetylamino-6-formylamino-1-methyluracil (AFMU) and 1-methylxanthine (1X) were analyzed by high performance liquid chromatography (HPLC). The frequency histogram and probit plot were constructed to select the critical value which was used to assess slow and fast acetylation status both in healthy volunteers and patients with bladder cancer. RESULTS: The peak height ratios of AFMU and 1X (AFMU/1X) were from 0.06 to 6.50 for healthy volunteers and 0.10 to 6.31 for patients with bladder cancer, both with the critical value of 1.10. Of 203 healthy volunteers involved in this study, 26.3% were slow acetylacors, as compared to 46.3% with slow acetylacors in patients with bladder cancer. The odds ratio is 2.376, and the gene frequency for healthy volunteers and patients with urinary bladder cancer were 0.5218 and 0.6804, respectively. CONCLUSIONS: N-acetylation status in the Chinese population is polymorphic and completely concordant with that determined with other metabolic probes. Slow acetylators are significantly associated with bladder cancer.

Acetylation↗

PubMed2000

[Postoperative recurrence of T2 stage gastric cancer].

OBJECTIVE: To study the clinicopathological characteristics of T(2) gastric cancer and its postoperative recurrence. METHOD: 124 T(2) gastric cancer patients were divided into two groups: 42 patients with postoperative recurrence (Group 1) and 82 patients without recurrence (Group 2). RESULTS: The recurrence rate of local tumor was significantly lower in Group 1 (26.2%) than in Group 2 (45.1%). Deep invasion was highly different between the two groups. Circular muscle tumors were seen in Group 1 (4.8%) and in Group 2 (30.5%), whereas sub-serosa tumors were seen in Group 1 (61.8%) and in Group 2 (25.6%). The rate of lymph node metastasis was significantly higher in Group 1 (88.1%) than in Group 2 (57.3%). The mean number of positive nodes was (7.02 +/- 6.50) in Group 1 and (2.16 +/- 2.04) in Group 2(P < 0.01). Local recurrence rate and distant metastasis rate in Group 1 were 54.8% and 46.2% respectively. The median survival was 26.5 months in Group 1 and 57.0 months in Group 2 (P < 0.01). The 1-, 3-, 5-year survival rate in Group 1 and Group 2 were 61.4% vs 97.6%, 18.7% vs 95.9%, and 8.3% vs 95.9%, respectively. CONCLUSION: Poor prognosis is seen in T(2) gastric cancer patients with postoperative recurrence. Extended gastrectomy and multi-therapy are necessary for the patients with the risk factors so as to decrease local recurrence.

Adult↗

PubMed2000

[Study on the epidemiology of diabetes mellitus in peasants with different income in Binzhou prefecture Shandong province].

OBJECTIVE: In order to study the morbidity of diabetes mellitus (DM), impaired glucose tolerance (IGT), and main effective factors of peasants with different income in poor area and to provide scientific data for strategy development. METHODS: The regions of investigation were divided into five parts: east, south, west, north and centre with two and three villages randomly selected for study from each region. Glucose - oxidase method was used to measure blood sugar and urine sugar. The classification and diagnosis standard were referred from the Beijing conference in 1980. RESULTS: The morbidity rates of non - insulin - dependent diabetes mellitus (NIDDM) and IGT were 1.21% and 2.35% in peasants who earned 800 and 2,500 yuan every year respectively. The standardized morbidity of NIDDM and IGT were 0.96% and 1.98%. We found that morbidity of NIDDM and IGT was very low among those younger than 20 years old but increased with age until reaching the top at the age of 70 to 80 years. DM patients were prominently seen at 30 to 40 year olds and IGT at 20 to 30 year olds. There was no difference of morbidity between male and female seen (chi(2) = 0.19 and 0.12; P > 0.05 and 0.05). The morbidity rates of DM and IGT in poverty type peasants who earned less than 1,200 yuan every year were 2.23% and 3.55% respectively, higher than those with adequate food and clothing type peasants who earned 2,000 to 2,500 yuan every year (morbidity rates were 0.39% and 1.18%; chi(2) = 18.11 and 18.10, P < 0.05 and 0.005) and those with common type of peasants who earned 1 200 to 1,900 yuan every year (morbidity rates were 0.80% and 1.92%; chi(2) = 25.85 and 18.20, P < 0.005 and 0.005). CONCLUSION: These results showed that sex did not obviously relate to morbidity of DM and IGT while age was one of the risk factors. The differences of income and unhealthy food intake played an role in the difference of morbidity to DM and IGT. It is important to increase the income of peasants and to change the unhealthy life style.

Adolescent↗

PubMed2000

[Aortic calcification and matrix metalloproteinases].

OBJECTIVE: To study the relationship between arterial calcification and matrix metalloproteinases including MMP-1 and MMP-3. METHODS: 15 human aorta specimens from autopsies were stained with HE to identify calcification. Immunohistochemical method was used to determine the secretion of MMP-1 and MMP-3. RESULTS: Among the 15 aorta specimens, calcification was found in 10 and no calcification in the remaining 5. There was no significant difference in the percentage of MMP-1 positive cells between two groups, with 83.8% +/- 5.2% in calcified specimens vs 84.0% +/- 7.5% in non calcified ones. 9 of the 10 calcified aortas were positive for MMP-3 staining. Serial sections showed that the localization of positivity was in concordance with calcified regions. The 5 normal aortas were MMP-3 negative. The difference between the two groups was significant. CONCLUSION: MMP-3 secretion relates closely with arterial calcification. And MMP-3 may participate in calcium minerali-zation in arteries. MMP-1 has no relation with arterial calcification.

Aorta↗

PubMed2000

[Effect of mouse p53 minigene on lung cancer cells with different 172 structures regulated by tetracycline].

OBJECTIVE: To investigate the effect of mouse 172 wild-type p53 (Arg), pseudo-wild-mutant-type p53 (Arg-->Leu) and mutant-type p53 (Arg-->His) induced by absence of tetracycline on the growth of PG cell line. METHODS: Three variant types of p53 minigene were sub-cloned by gene recombination into an expression vector which was controlled by tetracycline. Through LipofectAMINE, the vectors were transfected into p53 defective PG (248CGG-->CTT) cells, and the transfectants were screened in the selecting medium containing puromycin. Tumor suppressing effects were studied by MTT absorption, flow cytometry and Western blotting. RESULTS: Wild-type p53 and pseudo-wild-mutant-type p53 could lead cells to decrease their growth rates, arrest cell cycle and transactivation of p21(WAF1). Mutant-type p53 was defective in tumor suppression. CONCLUSION: Wild-type p53 and pseudo-wild-type p53 may inhibit cell growth and induce cell cycle arrest. Some p53 variants such as 172 Arg-->Leu can still retain the tumor suppression function of the wild-type.

Amino Acid Substitution↗