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Biomedical subjects

G Qi

Publications and source records attributed to G Qi.

At least 19 recordsLinked to original sources
PubMed2003

Bacterial virus phi29 pRNA as a hammerhead ribozyme escort to destroy hepatitis B virus.

The DNA-packaging pRNA of bacterial virus phi29, which forms dimers and then hexamers, contains two independent tightly self-folded domains. Circularly permuted pRNAs were constructed without impacting pRNA folding. Connecting the pRNA 5'/3' ends with variable sequences did not disturb its folding and function. These unique features, which help prevent two common problems - exonuclease degradation and misfolding in the cell, make pRNA an ideal vector to carry therapeutic RNAs. A pRNA-based vector was designed to carry hammerhead ribozymes that cleave the hepatitis B virus (HBV) polyA signal. The chimeric HBV-targeting ribozyme was connected to the pRNA 5'/3' ends as circularly permuted pRNA. Two cis-cleaving ribozymes were used to flank and process the chimeric ribozyme. The hammerhead ribozyme including its two arms for HBV targeting was able to fold correctly while escorted by the pRNA. The chimeric ribozyme cleaved the polyA signal of HBV mRNA in vitro almost completely. Cell culture studies showed that the chimeric ribozyme was able to enhance the inhibition of HBV replication when compared with the ribozyme not escorted by pRNA, as demonstrated by Northern blot and e-antigen assays. pRNA could also carry another hammerhead ribozyme to cleave other RNA substrate. These findings suggest that pRNA can be used as a vector for imparting stability to ribozymes, antisense, and other therapeutic RNA molecules in vivo.

Base Sequence↗
PubMed2001

[Activation of transcription factors and induction of cytokines from macrophages in chronic obstructive pulmonary disease].

OBJECTIVE: To investigate the activation of transcription factors and induction of cytokines from alveolar macrophages in chronic obstructive pulmonary disease (COPD). METHODS: Alveolar macrophages were collected by fibrobronchoscopy from 8 patients with chronic bronchitis, 8 patients with COPD, and 8 healthy volunteers. All patients were at stable stage. The macrophages thus collected were cultured and stimulated with lipopolysaccharide (LPS, 10 micrograms/ml). The IL-8, IL-1 beta, TNF alpha and IL-6 thus produced were measured by ELISA in the supernatant. Nuclear factor-kappa B (NF kappa B), activator protein-1 (AP-1), AP-2 and AP-3 were detected by electrophoretic mobility shift assay. RESULTS: The concentration of IL-8 released from macrophages of patients with COPD at stable stage before LPS stimulation was about 3 times higher than that in the healthy control (F = 4.34, P < 0.05). The concentration of IL-8 released from macrophages in patients with COPD was increased further after LPS stimulation in comparison to that in healthy controls(F = 3.56, P < 0.05). The concentration of IL-1 beta and that of TNF alpha released from macrophages of COPD patients were further increased after LPS stimulation (P < 0.05) in the COPD patients, but there was no difference in the concentration of IL-1 beta and between the control and COPD patients before LPS stimulation. The constitutive activity of AP-1 and the activity of NF kappa B induced by LPS were higher in the patients with COPD than in the controls. CONCLUSION: The alverlar macrophages of patients with COPD at stable stage may release higher concentration of IL-8 and IL-1 beta. LPS stimulation increases the release of IL-1 beta and TNF alpha of alveolar macrophages. Enhancement of activity of NF kappa B and AP-1 may positively regulate the production of IL-8 and IL-1 beta in the airflow obstruction.

Adult↗
PubMed2000

Attenuation of acoustic emission body waves in acrylic bone cement and synthetic bone using wavelet time-scale analysis.

This article addresses acoustic emission (AE) wave attenuation in acrylic bone cement and wave attenuation due to the existence of material interface between acrylic bone cement and sawbone. In this article, a series of tests were performed using standard pencil lead break sources. The attenuation features inside acrylic bone cement and sawbone materials and the attenuation due to the existence of material interfaces such as cement-cement and cement-sawbone were studied. In addition, the discrete wavelet-based signal energy decomposition method was introduced to examine detail breakdown of signal energy distribution of attenuation. From the tests, it was observed that the attenuation of AE signal was linear with respect to the wave travel distance for both energy and amplitude. Furthermore, AE energy attenuation was more sensitive than AE amplitude attenuation. In the analysis of attenuation due to material interfaces, the couplant plays a major role in reducing the attenuation at the interfaces. The attenuation at an interface composed by different material is less compared with an interface composed by the same material.

Acoustics↗
PubMed2000

3-D AE visualization of bone-cement fatigue locations.

This study addresses the visualization of crack locations in bone-cement material using a three-dimensional acoustic emission source location technique. Computer software based on an earthquake location technique was developed to determine AE source locations and was used to investigate material cracks formed at the tip of a notch in bone cement. The computed locations show that the cracks form linear features with dimensions between 0.1 and 0.2 mm although larger linear features (almost 3.5 mm) also are present. There is a difference of about 2.5 mm between the average of the event locations, and the location of the tip of the notch is 2.5 mm, which may be due to the finite size of the sensors (5 mm in diameter).

Animals↗
PubMed2000

Protective effect of gypenosides on DNA and RNA of rat neurons in cerebral ischemia-reperfusion injury.

AIM: To observe the protective effect of gypenosides (GP) on the neurons of hippocampus, cerebral cortex, corpus striatum, and dentate gyrus in cerebral ischemia-reperfusion injury of rats. METHODS: Modified 4-vessel occlusion (4-VO) method was used to establish the model of acute global ischemia. The acridine orange (AO) staining method was used to observe the DNA and RNA contents of cerebral ischemia-reperfusion injury model in the areas. RESULTS: The fluorescent intensity (reflecting DNA and RNA contents) of the DNA and RNA in the areas of cerebral ischemia-reperfusion injury was markedly abated compared with the normal control group. In the group of ig GP (100 mg/kg) it was enhanced compared with the model group and was the same as the normal control group. CONCLUSION: The injury of the DNA and RNA in the areas of ischemia-reperfusion model was decreased by GP.

Animals↗
PubMed2000

Detecting residual ischemia and identifying coronary artery disease after myocardial infarction using dobutamine technetium-99m-MIBI SPECT.

OBJECTIVE: To evaluate dobutamine technetium-99m methoxy isobutyl nitrile (sestamibi) single-photon emission computed tomography (Dobu-ECT) in detecting residual ischemia and identifying coronary vessel disease after myocardial infarction. METHODS: Sixty-two patients with confirmed myocardial infarction were studied with Dobu-ECT at the time of coronary artery angiography. Dobutamine was administered intravenously in incremental rates from 5 to 40 micrograms.kg-1.min-1 at 3-minute intervals. At the highest infusion rate, 7.4 x 10(8) Bq 99mTc-MIBI was injected intravenously, and tomographic imaging was performed after one hour. Resting images were taken after 24 hours, with a second dose of 99mTc-MIBI. RESULTS: The sensitivity of Dobu-ECT in detecting residual ischemia of myocardial infarction was 76%, which was higher than dobutamine electrocardiography (Dobu-ECG). Regardless of the single-, double- or triple-vessel diseases, Dobu-ECT was superior to Dobu-ECG in identifying residual ischemia (56% vs 4%, 86% vs 27%, 100% vs 47%, P < 0.01, respectively). The incidence of residual ischemia in patients receiving thrombolytic therapy was 67%, lower than patients without thrombolysis (72%) or those with an old myocardial infarction (94%). But the differences were not statistically significant. Dobu-ECT detected only 56% of ischemias in non-infarct related myocardium. Eighty-two percent of all significantly stenosed vessels were detected with Dobu-ECT, and 84% of patients with multivessel disease could be accurately identified. The sensitivity of Dobu-ECT was significantly greater for detecting severe stenosis over moderate stenosis. The sensitivity for detecting stenosis in the right coronary artery was greater than left anterior descending or left circumflex, but its specificity was lower. CONCLUSION: Dobu-ECT can identify residual ischemia, as well as its location and extent after myocardial infarction. Dobu-ECT can also accurately detect significantly stenosed vessels.

Adult↗
PubMed1999

Smoking in China: findings of the 1996 National Prevalence Survey.

CONTEXT: As the world's largest producer and consumer of tobacco products, China bears a large proportion of the global burden of smoking-related disease and may be experiencing a tobacco epidemic. OBJECTIVE: To develop an evidence-based approach supporting tobacco control initiatives in China. DESIGN AND SETTING: A population-based survey consisting of a 52-item questionnaire that included information on demographics, smoking history, smoking-related knowledge and attitudes, cessation, passive smoke exposure, and health status was administered in 145 disease surveillance points in the 30 provinces of China from March through July 1996. PARTICIPANTS: A nationally representative random sample of 128766 persons aged 15 to 69 years were asked to participate; 120298 (93.8%) provided data and were included in the final analysis. About two thirds of those sampled were from rural areas and one third were from urban areas. MAIN OUTCOME MEASURES: Current smoking patterns and attitudes; changes in smoking patterns and attitudes compared with results of a previous national survey conducted in 1984. RESULTS: A total of 41187 respondents smoked at least 1 cigarette per day, accounting for 34.1% of the total number of respondents, an increase of 3.4 percentage points since 1984. Current smoking continues to be prevalent among more men (63%) than women (3.8%). Age at smoking initiation declined by about 3 years for both men and women (from 28 to 25 years). Only a minority of smokers recognized that lung cancer (36%) and heart disease (4%) can be caused by smoking. Of the nonsmokers, 53.5% were exposed to environmental tobacco smoke at least 15 minutes per day on more than 1 day per week. Respondents were generally supportive of tobacco control measures. CONCLUSION: The high rates of smoking in men found in this study signal an urgent need for smoking prevention and cessation efforts; tobacco control initiatives are needed to maintain or decrease the currently low smoking prevalence in women.

Adolescent↗
PubMed1999

Knowledge of HIV/AIDS among health care workers in China.

This study was designed to assess knowledge of AIDS among health professionals in China via a cross-sectional survey. A self-administered questionnaire requesting demographic characteristics and basic AIDS knowledge was given to health professionals in 11 provinces, cities, and autonomous regions. Questionnaires were completed by 1,400 of 1,500 (93%) health professionals surveyed. The percentages of correct answers ranged from 3% to 68%. Findings included that public health workers had more knowledge than clinicians; having attended training workshops was not associated with an adequate levels of knowledge; and knowledge differed by professional level and by the geographic region in which they worked. Although most health professionals questioned knew that AIDS is caused by an infectious agents, their knowledge of transmission routes, the "window period" and the length of the incubation period is still inadequate. Thus, health professionals in China urgently need both more training and more effective training. The effectiveness of future HIV/AIDS workshops should be evaluated.

Acquired Immunodeficiency Syndrome↗
PubMed1999

[The effects of Xuezhikang on neointimal proliferation and C-myc gene expression after angioplasty in rabbits].

OBJECTIVE: To investigate the effects of Xuezhikang (XZhK) on the neointimal proliferation and C-myc gene expression after angioplasty in rabbits. METHODS: Angioplasty for atherosclerotic stenosis of celiac arteries was performed in 30 male white rabbits after being fed with cholesterol-supplemented diet for 8 weeks, which were then randomized to control group, high-cholesterol group and XZhK group. After 4 weeks, the local vessels were collected for morphological observation. C-myc mRNA level was measured with RT-PCR and C-myc protein with immunohistochemical analysis. RESULTS: Morphological observation showed that the neointimal area in the XZhK group were less than the control group (P < 0.05), and that in control group were less than that in the high-cholesterol group (P < 0.05). The levels of C-myc mRNA measured with RT-PCR and the percentage of C-myc protein positive cell by immunohistochemical analysis were lower in the XZhK group than in the control and high-cholesterol group (P < 0.05), The levels in the latter two groups showed no difference (P > 0.05). CONCLUSION: XZhK can inhibit the neointimal proliferation and the expression of C-myc gene after angioplasty in rabbits.

Angioplasty, Balloon↗
PubMed1999

[The effects of inhaled bronchodilators on central inspiratory drive in patients with COPD].

OBJECTIVE: To evaluate the effects of inhaled bronchodilators on the central inspiratory drive in patients with COPD. METHODS: 91 patients with COPD were divided into three groups (A, B, C) randomly. Lung functions and P(0.1) were measured at baseline and 20 min and 60 min after inhalation (A: albuterol; B: iprotropium; C: albuterol + iprotropium). RESULTS: P(0.1) decreased after inhalation in all three groups (P < 0.05 approximately 0.001). A positive correlation between DeltaP(0.1) and DeltaFRC was found in the three groups (r = 0.4325 - 0.5230, P < 0.05 approximately 0.01). V(E)/P(0.1) increased in the three groups after inhalation (P < 0.05 approximately 0.005). There was significant improvement of V(E)/P(0.1) in group B and C as compared with that of group A (P < 0.05, P < 0.001); There was a different correlative factor with V(E)/P(0.1) in group B and C. CONCLUSIONS: (1) P(0.1) decreased after inhalation, It may be caused by decreased FRC. (2) V(E)/P(0.1) became appropriate after inhalation in all groups; The improvement in group B and C was superior to that of group A. There may be different mechanisms to improve V(E)/P(0.1) by different inhalators.

Administration, Inhalation↗
PubMed1999

[Measurement of liver volume and its clinical significance in cirrhotic patients].

OBJECTIVE: To evaluate whether, preoperative measurement of liver volume is of value to the evaluation of tolerance to operation and long-term prognosis in cirrhotic patients with portal hypertension. METHODS: We assessed liver volume in 18 cirrhotics and 31 noncirrhotic controls with 3-dimensional shaded surface display by CT twin. RESULTS: The liver volume in controls was positively correlated to the height (r = 0.42, P < 0.05). The average of liver volume in controls was (1 070.68 +/- 227.52) cm(3) and was different from that of cirrhotics (797.02 +/- 135.11) cm(3) (P < 0.05). Liver volume of cirrhotic patients with portal hypertension was related to their Child classification. The liver volume of patients in Child C group was significantly smaller than that of patients of Child B group. CONCLUSIONS: The patients with smaller liver volume are likely complicated by encephalopathy after shunting procedure. However, the liver volume is not significantly correlated with portal blood flux and portosystemic shunt index.

Adult↗
PubMed1998

Reversion of multidrug resistance in the P-glycoprotein positive breast cancer cell line (MCF-7/ADR) by introduction of hammerhead ribozyme.

A hammerhead ribozyme which site-specifically cleaved the GUC position in codon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function of the P-Gp as an ATP-dependent pump. A DNA sequence encoding the ribozyme gene was then incorporated into a eukaryotic expression vector (pH beta Apr-1 neo) and transfected into the breast cancer cell line MCF-7/Adr, which is resistant to adriamycin and expresses the MDR phenotype. The ribozyme was stably expressed in the cell line by the RNA dot blotting assay. The result of Northern blot assay showed that the expressed ribozyme could decrease the level of mdr1 mRNA expression by 83.5%; and the expressed ribozyme could inhibit the formation of P-glycoprotein detected by immuno-cytochemistry assay and could reduce the cell's resistance to adriamycin; this means that the resistant cells were 1,000-fold more resistant than the parental cell line (MCF-7), whereas those cell clones that showed ribozyme expression were only 6-fold more resistant than the parental cell line. These results show that a potentially useful tool is at hand which may inactivate MDR1 mRNA and revert the multidrug resistance phenotype.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Physiological basis for long life span.

A collection of clinical data is reported on nonagenarians in comparison to an 'average' population of younger age. The results of these clinical data indicated that a vital physiological basis for long life span probably existed. The basis include a better micro-blood-flow state, a better cardiac, immune (nature killer cell activity), adrenocortical, hepatic and renal function, and a higher level of high density lipoprotein cholesterol. It is suggested that the method, including Chinese traditional medicine, to improve the micro-blood-flow, nature killer cell activity, high density lipoprotein cholesterol and vital organ function may be beneficial for life preservation and aging retarding.

Aged↗
PubMed1997

[Portal-systemic shunting and hemodynamics of prehepatic portal hypertensive rat models].

Hemodynamics and relationship between portal-systemic shunting and portal pressure were measured by radioactive microsphere techniques in 31 rats after various degree portal vein constriction. Prominent hyperdynamic state was present in prehepatic portal hypertensive rats models. Both cardiac output and index were increased, the mean arterial pressure and pripheral resistance were reduced significantly. The total splanchnic blood flow was increased but splanchnic resistance reduced remarkably. Portal-systemic shunting flow was higher. There was a significant positive correlation between them, Y = 26.14 + 5.32X (r = 0.76, P < 0.001). For this reason, elevated systemic and portal venous flow provided main impetus for maintaining portal hypertension.

Animals↗
PubMed1997

[Gastric mucosal hemodynamics of prehepatic portal hypertensive rat model].

OBJECTIVE: To observe the changes of gastric mucosal hemodynamics and discuss the possible regulatory factors of prehepatic portal hypertensive rat. METHOD: Prehepatic portal hypertensive (PHT) rat model was produced by various degree of portal vein constriction, and gastric mucosal hemodynamics was measured by radioactive microsphere technique. Statistical analysis was performed by ANOVA, the student t test, and linear correlation. RESULT: The gastric mucosal blood flow was significantly reduced in PHT rats, whereas the blood flow in submucosa, muscular layer prominently increased. The resistance of mucosal vasculature was elevated in PHT rats, however, that of submucosa and muscular layer was decreased remarkably. There was a negative correlation between the gastric mucosal blood flow and portal pressure. CONCLUSION: The gastric mucosa of prehepatic portal hypertensive rat model is poorly perfused prominently. It may be due to the increased mucosal vascular resistance and elevated portal pressure.

Animals↗
PubMed1996

Stable expression of anti-HPV 16 E7-ribozyme in CV-1 cell lines.

The HPV16 (human papilloma virus type 16) E7 gene product, an oncoprotein, has been considered to be involved in the pathogenesis of anogenital cancer, particularly of cervical cancer. In order to evaluate the effect of suppression of the expression of the E7 gene in CV-1 cells by ribozyme, Rz523 with a transacting ribozyme targeted to the E7 RNA and two processing ribozyme genes at the 5' and 3' flank was cloned into the eukaryotic expression plasmid pREP9 under the control of RSV-LTR promoter. The resultant plasmid pRSV-Rz523 was transfected into CV-1 cells by calcium phosphate coprecipitation. The expression of the ribozyme in G418-resistant cells was detected by dot-blot hybridization. Ribozymes stably expressed in the CV-1 cells were at a level of 9.0 pmol per 10(6) cells, in which the active ribozyme molecules were more than 50 fmol per 10(6) cells. The result of RNase protection assay showed that the steady-state level of the E7 RNA fragment in CV-1 cell lines was significantly reduced by about 90% in ribozyme-expressing cells. In contrast, the antisense control plasmid pRSV-AE7 only exhibited about 20%. This result implicated the possibility of reversing the malignant phenotype of cervical cancer by means of suppressing the expression of the E7 gene with ribozyme.

Cell Line↗
PubMed1996

[Comparative observation on the relationship between the MEFV and the visual inspection of small airway].

OBJECTIVE: To compare the relationship between the MEFV and the visual inspection of small airway. METHODS: According to the result on small airway function test (MEFV), the patients were divided into two group: MEFV abnormal group and MEFV normal group. Their bronchus and peripheral airway were observed with bronchofiberscope and ultra-thin bronchofiberscope. The visual appearance of the airways was scored in the light of the presence or absence of erythema, edema, secretions, etc. RESULTS: The score of visual appearance observed or bronchitis index (BI) in small airway was 7.7 +/- 0.8 (BI: 3.0 +/- 0.8) and 4.7 +/- 1.6 (BI: 1.5 +/- 0.5) respectively in MEFV abnormal group and in MEFV normal group, namely the score in MEFV abnormal group was significantly higher than that of normal group (P < 0.01). The degree of pathological change in small airway was significantly correlated with the results of V25, V50, r = -0.6271, (P < 0.05) and r = 0.6964, (P < 0.02). CONCLUSION: The abnormal of MEFV may reflect inflamative pathological changes of small airway.

Asthma↗