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Biomedical subjects

H Qi

Publications and source records attributed to H Qi.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Study on endothelin-1 positive expression and quantitative analysis in lung cancer].

OBJECTIVE: In order to study endothelin-1 (ET-1) positive expression in lung cancer and the relationship between the ET-1 quantitative analysis and the types, grades of lung cancer. METHOD: ET-1 positive expression and quantitative analysis were detected using avidin-biotin-peroxidase complex method and image analysis technology. RESULT: The ET-1 positive expression were mainly located in the cytoplasm in 104 cases with various types of lung cancer. The positive rate of ET-1 in adenocarcinoma, squamous-cell carcinoma and large-cell-lung cancer were 71.4%, 57.1% and 40.0% respectively. The positive rate of ET-1 in small-cell-lung cancer was 21.4%, significantly lower than others. The results of image analysis on adenocarcinoma and squamous-cell carcinoma showed that the lower lung cancer differentiation, the higher ET-1 quantitative. CONCLUSION: There is ET-1 positive expression in all of types of lung cancer, but there is a high ET-1 positive expression in adenocarcinoma and squamous-cell carcinoma. The results of image analysis indicated that ET-1 quantitive expression was somehow related to the differentiation degree of neoplasm, so ET-1 quantitative analysis may be as a monitoring index of adenocarcinoma and squamous-cell carcinoma growing.

Adenocarcinoma↗
PubMed1998

[Assessment of effect of Shexiang Baoxin pill for labour angina pectoris patients with computerized tomography myocardial imaging].

OBJECTIVE: To assess the effect of Shexiang Baoxin Pill (SXBXP) for labour angina pectoris. METHODS: Effect of 66 patients treated with conventional treatment or conventional treatment plus SXBXP were observed and compared with 99mTC-MIBI single photon emission computerized tomography (SPECT) target cardiograph to estimate ischemia myocardial area. RESULTS: The total effective rate was much higher in patients treated with SXBXP than that in patients treated with conventional treatment only (87.8% vs 56%, P < 0.05). The effective rate on ECG in the two groups was 70.7% and 52.0% respectively, without significant statistical difference between them(P > 0.05). While significant difference was observed in ischemia area of myocardial image between the two groups after treatment, 18.2 +/- 8.2% vs 23.8 +/- 9.8%, P < 0.05. Moreover, the recurrence of angina pectoris and cardiac event were also less in the SXBXP group. CONCLUSION: The SXBXP was effective for labour angina pectoris.

Aged↗
PubMed1997

Intracellular cleavage of Notch leads to a heterodimeric receptor on the plasma membrane.

Previous models for signal transduction via the Notch pathway have depicted the full-length Notch receptor expressed at the cell surface. We present evidence demonstrating that the Notch receptor on the plasma membrane is cleaved. This cleavage is an evolutionarily conserved, general property of Notch and occurs in the trans-Golgi network as the receptor traffics toward the plasma membrane. Although full-length Notch is detectable in the cell, it does not reach the surface. Cleavage results in a C-terminal fragment, N(TM), that appears to be cleaved N-terminal to the transmembrane domain, and an N-terminal fragment, N(EC), that contains most of the extracellular region. We provide evidence that these fragments are tethered together on the plasma membrane by a link that is sensitive to reducing conditions, forming a heterodimeric receptor.

Blotting, Western↗
PubMed1997

Regulation of Escherichia coli topA gene transcription: involvement of a sigmaS-dependent promoter.

To investigate the regulation of Escherichia coli topA gene transcription, primer extension was employed to determine the transcription initiation sites from the chromosomal topA gene. When cells were grown in LB medium to log phase, four transcription initiation sites could be identified. Three of these sites corresponded to promoters P1, P2 and P4 previously characterized using topA-galK fusion plasmids. The P3 promoter that is active on the plasmid was not utilized at the chromosomal topA gene under the conditions employed. There was a new transcription initiation site corresponding to a new promoter Px1. When cells started to enter stationary phase, promoter Px1 gradually became the major transcription initiation site for topA, while transcription from promoters P2 and P4 decreased. In an E. coli mutant lacking sigmaS (the rpoS gene product), the stationary phase specific sigma factor, the induction of transcription from promoter Px1 was abolished. In another mutant lacking H-NS activity, resulting in increased sigmaS level in log-phase, the transcription from promoter Px1 during log phase was increased. Thus Px1 appeared to be regulated by sigmaS. The activity of promoter P1 on the chromosome increased during heat shock, consistent with the previous result obtained using the topA-galK fusion plasmid showing that P1 is a sigma32-dependent heat shock promoter. Promoters P2 and P4 were most likely to be recognized by sigma70. The total level of topoisomerase I protein in the rpoS mutant was not reduced significantly in stationary phase due to increased transcription initiation from the other topA promoters. The utilization of multiple sigma factors for transcription initiation of topA could be important for adaptation of E. coli to change in growth conditions.

Bacterial Proteins↗
PubMed1997

Mutant female mice carrying a single mZP3 allele produce eggs with a thin zona pellucida, but reproduce normally.

The mouse egg zona pellucida (ZP) is composed of three glycoproteins, called mZP1-3. Disruption of the mZP3 gene by targeted mutagenesis yields mice that are homozygous (mZP3-/-) for the null mutation; although the mutant mice are viable, females are infertile and their eggs lack a ZP. On the other hand, females heterozygous (mZP3+/-) for the mutation are fertile and their eggs have a ZP. Here, we examined fully grown oocytes from mZP3+/- females and found that, although they have a ZP, it is less than half the width (approximately 2.7 microns; volume, approximately 56 pl) of the ZP of oocytes from wild-type (mZP3+/+) mice (approximately 6.2 microns; volume, approximately 145 pl). Oocyte ZP were purified from ovarian homogenates by gradient centrifugation. Immunostaining of purified ZP on Western gels permitted an estimate to be made of the relative amounts of mZP3 and mZP2 present in the ZP of oocytes from mZP3+/+ and mZP3+/- mice. We found that the ZP from mZP3+/- mice contained, on average, 55 +/- 15% of the mZP3 and 44 +/- 8% of the mZP2 present in the ZP of mZP3+/+ mice; a result quite consistent with the observed widths and calculated volumes of the ZP. Despite the presence of a relatively thin ZP surrounding their eggs, reproduction of female mZP3+/- mice was indistinguishable from female mZP3+/+ mice. These results strongly suggest that, when a single mZP3 allele is present, approximately half the wild-type amount of mZP3 and approximately half the wild-type amount of mZP2 is assembled into a ZP. While this produces a relatively thin ZP, it apparently has no affect on reproduction. Furthermore, these results are consistent with the current molecular model for ZP structure.

Alleles↗
PubMed1997

Targeting the secretory pathway of Toxoplasma gondii.

Little is known about the extent of conservation in the organization of the secretory pathway in organisms as different as prokaryotes, eukaryotes, and humans. The protozoan parasite Toxoplasma gondii allows easy genetic manipulations, and numerous vectors for selection of transgenic parasites have been developed. One approach to study the molecular mechanism of protein sorting and trafficking is the expression of foreign proteins. Here we describe the design and application of a vector that targets proteins to the secretory pathway of T. gondii and yields high-level expression of Escherichia coli reporter proteins. The general strategies and potential problems in expressing foreign proteins in T. gondii are discussed.

Amino Acid Sequence↗
PubMed1997

Involvement of chromosomes 6 and 11 in a soft tissue chondroma.

Cytogenetic analysis of a soft tissue chondroma revealed monosomy 6 and rearrangement of chromosome 11. Previously described 12q13-q15 involvement was not found. Aberrations of chromosomes 6 and 11, however, have been reported before in this type of benign cartilaginous tumor.

Adult↗
PubMed1997

Monosomy 22 in a fibrothecoma.

We found a 45,XX, -22 karyotype as the sole chromosome change in a fibrothecoma of a 67-year-old woman. These cytogenetic findings are discussed in the light of relevant cytogenetic and pathology literature data on ovarian sex cord tumors.

Aged↗
PubMed1997

DNA supercoiling and bacterial adaptation: thermotolerance and thermoresistance.

When bacterial cells are shifted to higher temperatures their degree of DNA supercoiling changes. Topoisomerases are involved in bacterial adaptation to environmental changes requiring rapid shifts in gene expression. This role in heat shock has been elucidated by genetic studies on the Escherichia coli topA gene and its sigma 32-dependent promoter, P1. Other studies have shown that certain gyrA mutants have increased thermoresistance.

Adaptation, Physiological↗
PubMed1997

Comparative effects of droloxifene, tamoxifen, and estrogen on bone, serum cholesterol, and uterine histology in the ovariectomized rat model.

The purpose of this study was to compare the effects of droloxifene (DRO), tamoxifen (TAM), and 17 alpha-ethynyl estradiol (EE) on bone mineral density, bone histomorphometry, total serum cholesterol, and uterine histology in the ovariectomized (ovx) rat model. Sprague-Dawley female rats at five months of age were sham-operated and treated orally with vehicle (n = 8), or ovx (n = 56) and treated (p.o.) with either vehicle, DRO at 0.1 or 1.0 mg/kg daily, TAM at 0.1 or 1 mg/kg daily, or EE at 3 or 30 micrograms/kg daily for 4 weeks. The uterine wet weight and uterine histologic parameters (cross-sectional tissue area, stromal thickness, and luminal epithelial thickness) were determined. Femoral and lumbar vertebral bone mineral density was determined ex vivo using dual energy x-ray absorptiometry. Static and dynamic cancellous bone histomorphometry was performed on double-labeled, undecalcified longitudinal sections from proximal tibial metaphyses. Furthermore, the changes in total serum cholesterol and body weight gain were also determined. Compared to sham controls, ovx for four weeks significantly decreased uterine weight (-72%), uterine cross-sectional tissue area (-74%), stromal thickness (-52%), and luminal epithelial thickness (-53%). ovx rats treated with EE at 30 micrograms/kg/day maintained these parameters at the levels of sham controls. Uterine weight and uterine cross-sectional tissue area in 3 micrograms/kg/day of EE treated ovx rats were higher than that of vehicle-treated ovx rats. In ovx rats treated with TAM at both 0.1 and 1 mg/kg/day, these parameters were significantly less than sham controls but significantly higher than ovx controls. DRO at 0.1 mg/kg/day had no effects on all above parameters. Uterine weight and cross-sectional tissue area in 1 mg/kg/day of DRO treated ovx rats was slightly but significantly higher than that in ovx controls. However, DRO at 1 mg/kg/day had no effects on uterine stromal thickness and luminal epithelial thickness compared to ovx controls. The ovx-induced decrease in femoral and lumbar vertebral bone mineral density was prevented by treatment with EE at 30 micrograms/kg/day, TAM at both 0.1 and 1 mg/kg/day, or DRO at 1 mg/kg/day. Similarly, the decrease in bone mass and the increase in bone resorption and bone turnover in proximal tibial metaphyses were prevented by treatment with EE at 30 micrograms/kg/day or TAM at both 0.1 and 1 mg/kg/day, or DRO at 1 mg/kg/day. Total serum cholesterol decreased significantly in ovx rats treated with either EE, DRO, or TAM at all dose levels compared to vehicle treated ovx controls (-32% to -56%). The ovx-induced body weight gain was completely prevented by EE at 30 micrograms/kg/day, and partially prevented by DRO at 1 mg/kg/day. TAM at both 0.1 and 1 mg doses caused a significant decrease in body weight compared to both sham and ovx controls. Our results indicated that DRO prevented ovx-induced bone loss and lowered total serum cholesterol with an ED50 less than 1 mg/kg/day. The bone protective and cholesterol lowering effects of DRO were comparable to those observed with TAM and EE. However, DRO differed from TAM and EE in its lack of significant estrogenic effects on uterine tissue at doses which were bone protective. These data suggest that DRO may be a significant alternative to EE and TAM for prevention and treatment of postmenopausal osteoporosis.

Absorptiometry, Photon↗
PubMed1997

Factors controlling the efficiency of cationic lipid-mediated transfection in vivo via intravenous administration.

The factors controlling the transfection efficiency of cationic lipid carrier systems following intravenous administration are poorly understood. Using N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA) combined with Tween 80 as a carrier system and cDNA of luciferase or beta-galactosidase gene as a reporter, we investigated the importance of DOTMA to DNA ratio and the ratio of DOTMA to Tween 80 in the lipid formulation in determining the site and level of transgene expression following intravenous administration. The data show that all of the internal organs, including lung, liver, spleen, heart and kidneys, expressed the transgene upon systemic administration into animals with 25 micrograms of plasmid DNA when complexed with DOTMA-Tween 80 lipid formulation. The transfection efficiency was dependent on both DOTMA to DNA, and DOTMA to Tween 80 ratios. Among the organs examined, the lung appeared to be more transfectable than other organs. A better transfection activity was obtained with higher DOTMA to DNA and DOTMA to Tween 80 ratios. Time-response curve shows that gene expression was transient with a maximal level between 10 and 24 h after injection. Results from tissue distribution studies with 125I-labeled plasmid DNA and Southern analysis suggest that the transient expression is the result of the loss of transgene from the transfected cells. These results suggest that cationic lipid-based delivery systems can be efficient for gene delivery if the composition of the DNA-lipid complexes is properly controlled.

Animals↗
PubMed1997

Inhibitors of trypsin-like serine proteases inhibit processing of the caspase Nedd-2 and protect PC12 cells and sympathetic neurons from death evoked by withdrawal of trophic support.

Rat pheochromocytoma (PC12) cells and sympathetic neurons undergo apoptotic cell death upon withdrawal of trophic support. We have shown previously that selective cysteine aspartase (caspase) inhibitors protect PC12 cells and sympathetic neurons from such death, and that the caspase Nedd-2 is required for this type of death to occur. We now show that 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) and N(alpha)-p-tosyl-L-lysine chloromethyl ketone (TLCK), agents that inhibit another class of proteases, the trypsin-like serine proteases, also suppress cell death in this paradigm. The site of action of these agents is upstream of the caspases, because the CPP32-like and Nedd-2-cleaving activities that are induced upon withdrawal of trophic support in PC12 cells are inhibited when AEBSF and TLCK are applied to the cells. Both agents inhibit thymidine incorporation in PC12 cells at concentrations similar to those that promote survival, raising the possibility that they may promote survival in neuronal cells through inhibition of aberrant activation of cell cycle components.

Animals↗
PubMed1997

[Study on relationship between proto-oncogene expression of c-fos and c-myc in airway, lung tissue and asthma in guinea pigs].

In order to investigate the mechanism of the attack of asthma, the authors examined the proto-oncogene expression of c-fos and c-myc in the airway and lung tissue of the ovalbumin-induced asthmatic guinea pigs by using Dot-blot. Northern-blot and immunohistochemical techniques. There was a baseline expression of c-fos and c-myc in the controls, whereas the mRNA expression of c-fos and c-myc increased much more significantly in asthmatic guinea pigs, it reached maximum at 30 min after the onset of asthma and it was in a time dependant manner. The inducement could be inhibited partially by dexamethasone. Immunohistochemical investigation showed that c-fos and c-myc was distributed mainly in epithelial cells of the airway. The staining was more intensive in the asthmatic guinea pigs than in the controls. The results suggest that the increase in proto-oncogene expression of c-fos and c-myc may be related to the attack of asthma.

Animals↗
PubMed1997

[The relationship between interleukin-8 and airway hyperresponsiveness].

OBJECTIVE: To explore the relationship between interleukin-8 (IL-8) and airway hyperresponsiveness (AHR) of asthma. METHOD: IL-8 at a dose of 0.5 microgram/kg or 5 micrograms/kg was administered intranasally to guinea-pigs twice a week for 3 weeks. 24 hours after the last administration, airway responsiveness was measured as an overall index of airway response to increasing concentrations of inhaled histamine (25, 50, 100 and 200 micrograms/ml) and the numbers of different inflammatory cells in bronchoalveolar lavage fluid (BALF) was counted. RESULTS: The IL-8 treatment significantly enhanced airway responsiveness to histamine in a dose-dependent manner (P < 0.05 or 0.01) and induced a significant influx of neutrophils in BALF (P < 0.01), and there are many neutrophils within airway wall but not control animals treated with phosphate buffered saline (PBS). CONCLUSION: The IL-8 given into the airways can produce neutrophil inflammation of the airways and induce AHR, it may play an important role in asthma, especially in the development of AHR.

Animals↗
PubMed1997

[Chlamydia trachomatis and Ureaplasma urealyticum infection in patients with tubal pregnancy].

OBJECTIVE: To explore the relationship between genital infections with chlamydia trachomatis (CT) and ureaplasma urealyticum (UU) and tubal pregnancy. METHODS: 34 patients with tubal pregnancy (case group), 28 women undergoing tubal ligation (control group A) and 40 women with normal early intrauterine pregnancy (control group B) were investigated as a case-control study. The polymerase chain reaction (PCR) technique was used to detect CT DNA and UU DNA in samples from the secretion of cervix, fallopian tube and pelvic fluid. RESULTS: Case group was more likely to have detectable CT DNA (47.1%) and UU DNA (55.9%) from cervical secretion than control group A and B (P < 0.05). CT DNA detective rate from fallopian tube was significantly higher in case group than the control group A (26.5% versus 3.6%, P < 0.05). There were no significant differences in the positive rates of UU DNA from fallopian tube, CT DNA and UU DNA from pelvic fluid between case group and control group A. CONCLUSION: There is a strong association between tubal pregnancy and genital infection with CT and UU.

Adult↗
PubMed1996

Expression and immunoaffinity purification of human inducible nitric-oxide synthase. Inhibition studies with 2-amino-5,6-dihydro-4H-1,3-thiazine.

Recombinant human inducible nitric-oxide synthase (rH-iNOS) was expressed in the baculovirus system and purified by a novel immunoaffinity column. rH-iNOS and its native counterpart from cytokine-stimulated primary hepatocytes exhibited similar molecular mass of 130 kDa on SDS-polyacrylamide gel electrophoresis, recognition by antipeptide antibodies, specific activities, and IC50 values for inhibitors. The active dimeric form exhibited a specific activity range of 114-260 nmol/min/mg at 37 degrees C and contained 1.15 +/- 0.04 mol of calmodulin/monomer. The enzyme exhibited a Soret lambdamax at 396 nm with a shoulder at 460 nm and contained 0. 28-0.64 mol of heme/monomer. Dithionite reduction under CO yielded an absorbance maximum at 446 nm, indicating a P450-type heme. Imidazole induced a type II difference spectrum, reversible by L-Arg. 2-Amino-5,6-dihydro-4H-1,3-thiazine (ADT) was competitive versus L-Arg (Ki = 22.6 +/- 1.9 nM), reversed the type II difference spectrum induced by imidazole (Kd = 17.7 nM), and altered the CO-ferrous absorbance of rH-iNOS. L-Arg did not perturb the CO-ferrous adduct directly, but it partially reversed the ADT-induced absorbance shift, indicating that both bind similarly to the protein but interact differently with the heme.

Chromatography, High Pressure Liquid↗
PubMed1996

Fibrinogen levels in women having coronary angiography.

Fibrinogen has emerged as a risk factor for coronary artery disease in men that equals cholesterol in importance. It is known to play an important role in reparative processes, and evidence is accumulating that fibrinogen/fibrin accumulates at the site of minimal vascular injury. Fibrinogen contributes significantly to blood viscosity and its adherence to endothelium may mediate progression of atheromatous lesions. This study was designed to examine a number of markers of risk in a consecutive series of cardiology patients undergoing coronary catheterizations over a 15-month period. This article examines the level of fibrinogen in relation to the number of reported coronary stenoses and disease severity in a series of Caucasian female patients (n = 101). Women were classified as diseased if they had at least 1 lesion > or = 25% in the coronary anatomy and nondiseased if they had no lesions > or = 25%. The number of reported lesions correlates significantly with fibrinogen levels (r = 0.36, p = 0.0002). Women with fibrinogen levels > or = 283 mg/dl had a 3.2-fold increased risk (95% confidence interval 1.2 to 9.1) of having at least 1 stenosis > or = 25% after adjusting for age and diabetic status. Smoking and body mass index did not differ by disease status and thus did not confound the finding. Mean fibrinogen levels showed a progressive positive association with increasing clinically defined vessel involvement (stenosis > or = 50%).

Age Factors↗