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Biomedical subjects

Q Chen

Publications and source records attributed to Q Chen.

At least 505 records · Page 28Linked to original sources
PubMed1997

[Retroviral vector mediated gene transfer and expression of human GM-CSF in HL-60 leukemic cells].

OBJECTIVE: To study the condition and possibility for introducing foreign gene into myeloid leukemic cells and gene therapy for malignant tumors in hematology. METHODS: With Lipofectin technique, N2A/CMV/hGM-CSF was transfected into packaging cell line PA317 and recombinant retrovirus were obtained. Then the human myeloid leukemic cells HL-60 were infected with recombinant retroviral supernatant. Positive cells were obtained through the neomycin analogue G418 selection. RESULTS: Successful integration of GM-CSF gene into HL-60 cell genome was verified by PCR and Southern Blot, while no specific fragments were amplified by PCR test in HL-60 cells without being transferred or transferred with empty vector N2A. With measurement by GM-CSF dependent cell line TF-1, the level of GM-CSF released by the GM-CSF gene modi-fied HL-60 cell line was 60-200 ng.ml-1.10(-6).24 h-1, while the supernatant of HL-60 cells without being transferred or transferred with empty vector N2A. CONCLUSION: hGM-CSF gene mediated by retroviral vector can achieve efficient transfer and expression in HL-60 leukemic cells.

Gene Transfer Techniques↗
PubMed1997

[A study on the significance of p53 gene mutation, P53 protein positive staining and PCNA staining].

After obtaining the results of p53 gene mutation by a silver staining method to polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, P53 protein staining and proliferation cell nuclear antigen (PCNA) index by double-blind method, multivariate correlation analysis two by two showed that PCR-SSCP, P53 positive protein staining and PCNA index had markedly correlation not only in oral precancerous lesions (OPL) but also in primary sites and regional metastatic lymph nodes of oral squamous cell carcinomas (OSCC). This indicated that the nature of the three indexes was the same. After introducing the sex and age of patients which have been proved to be related to the initiation and development of OPL and OSCC according to other researchers and are easy to be obtained in clinics, multivariate discriminatory analysis was carried on and three groups of discriminatory equations were gotten about the pathological grading of OPL and OSCC and metastasis condition of OSCC. The accuracy of these equations was 82.5%, 78% and 80%, individually. This suggests that the equations have applicable potentiality already.

Carcinoma, Squamous Cell↗
PubMed1997

[Effects of nifedipine and cromakalim on isolated rat bladder tissue and aorta strip].

Relaxing effects of nifedipine and cromakalim on rat aorta strip, bladder ring and bladder strip were compared on receptor and KCl mediated contraction. The IC50 of nifedipine to inhibit NE induced contraction (by stimulation of alpha 1-adrenoceptor in aorta strip) was found to be 2.76 +/- 0.79 nmol.L-1. For the same action the IC50 of cromakalim (a potassium channel opener) was 48 +/- 25 nmol.L-1. However, to inhibit 27.5 mmol.L-1 KCl induced contraction, the IC50 for nifedipine and eromakalim were 1.83 +/- 1.3 nmol.L-1 and 64 +/- 19 nmol.L-1, respectively. On bladder ring, to inhibit carbachol mediated contraction (by cholinergic M-receptor stimulation), the IC50 for nifedipine and cromakalim were found to be 15 +/- 13 nmol.L-1 and 13 +/- 8.0 nmol.L-1, respectively. To inhibit KCl induced contraction, the IC50s were 2.05 +/- 1.26 nmol.L-1 and 38 +/- 26 nmol.L-1. On bladder strip, nifedipine and cromakalim antagonized carbachol mediated contraction, with IC50s of 12 +/- 12 nmol.L-1 and 32.0 +/- 2.4 nmol.L-1. Both compounds reduced the contraction force mediated by KCl with IC50 of 1.57 +/- 0.7 nmol.L-1 and 71 +/- 25 nmol.L-1, respectively. Our study showed that cromakalim was better to relax receptor mediated contraction of bladder ring. While, nifedipine was more potent to antagonize NE induced aorta strip contraction. Nifedipine also showed greater effect on KCl induced responses in all three tissue preperations.

Animals↗
PubMed1997

[A model atlas of the crude drug Radix Ophiopogonis in tri-dimensional computer reconstraction from their serial transections].

In this paper, the tri-dimensional computer reconstruction and animated display from the serial transections of the crude drugs Radix Ophiopogonis and Radix Liriopes have been achieved. Accordingly, some tri-dimensional image techniques and information for the computer aided teaching and identification of pharmacognosy have been offered.

Imaging, Three-Dimensional↗
PubMed1997

[Study on immunological pharmacology of keyin granule].

By intragastric keyin granule at the dosage of 1.0-4.0 g/kg.d[-1] for 7-10 days in mice, this drug can enhance the phagocytic function of the macrophages of peritoneal cavity, increase the index of spleen and the clearance rate of i.v. charcoal particles, obviously inhibit the formation of mouse-specific antibody and the delayed cutaneous hypersensitivity (DCH), recover the decrease of ANAE lymphocyte in periphery blood induced by cyclophosphamide. It can also improve the index of immunological organ of immunosuppression mice. These show the immunological regulative function of this drug.

Adjuvants, Immunologic↗
PubMed1997

[GM-CSF regulates the Vp16 induced leukemic cell apoptosis].

OBJECTIVE: To explore the regulatory effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on the apoptosis of leukemic cells induced by Vp16. METHODS: High expression retrovirus vector, N2A/CMV/GM-CSF, was constructed and transferred into human leukemic cell line HL-60, and Vp16 (final concentration 10microg/ml) was administered to transferred or nontransferred HL-60 cells. RESULTS: After Vp16 treatment, characteristic changes for apoptosis emerged in HL-60 cells. However, these findings did not emerge in GM-CSF gene transferred HL-60 cells. CONCLUSION: GM-CSF can suppress the leukemic cell apoptosis induced by Vp16.

Apoptosis↗
PubMed1997

[Study on the analysis of organogermanium compounds by ion chromatography].

A new high performance ion exchange chromatographic method for separation and determination of three organogermanium compounds beta-carboxyethylgermanium sesquioxide (I), beta-(alpha-methyl) carboxyethylgermanium sesquioxide (II) and di-(beta-carboxyethyl) germanium hydroxide (III) has been developed. A Dionex DX-300 Ion Chromatograph equipped with a Dionex PED-II pulsed electrochemical detector (conductivity mode), a Dionex AMMS-1 anion micromembrane suppressor, and a Dionex ACI advanced computer interface coupled with AI-450 chromatographic software was employed. The separation was achieved by using a Dionex IonPac AS4A-SC column as analytical column, sodium tetraborate solution as eluent, and sulfuric acid solution as regenerant. For reducing run time, a gradient program was chosen. The detection limits (S/N = 3, expressed as germanium) for the three compounds were 0.038mg/L (I), 0.035mg/L (II) and 0.025mg/L (III), respectively. The method has been applied to the analysis of two tonic oral drinks, and the average recoveries for the three compounds ranged from 95%-101%. The results obtained were in agreement with those of hydride generation atomic fluorescence spectrometry (HG-AFS).

Chromatography, Ion Exchange↗
PubMed1997

Effect of CO2 on intracellular pH and contraction of retinal capillary pericytes.

PURPOSE: To test the potential participation of pericytes in the regulation of capillary blood flow according to metabolic needs. METHODS: The authors measured the change in extracellular pH (pHo), intracellular pH (pHi), and contractile tone of cultured bovine retinal pericytes when the ambient carbon dioxide (CO2) level was changed. RESULTS: Raising the partial pressure of CO2 (PCO2) from 5% to 10% or 20% acidified the medium, decreased the pHi, and relaxed the pericytes. Lowering the PCO2 from 5% to 0% or 2% alkalized the medium, raised the pHi, and contracted the pericytes. The reactions of pericytes in both cases were dose dependent. When the pHo was kept at approximately 7.4 as the PCO2 was changed by adjusting the ratio of NaHCO3 and NaCl in the medium (or by using HEPES buffer when PCO2 was zero), both elevating and lowering the PCO2 caused intracellular acidification but did not change the contractile tone of the retinal pericytes significantly. CONCLUSIONS: The effect of CO2 on the pHi and the contractility of pericytes is mediated primarily by its influence on the pHo. Elevation of CO2 causes pericytes to relax, whereas dispersion of CO2 causes pericytes to contract under the condition that allows pHo to be affected by PCO2. Therefore, pericytes may contribute to the regulation of local blood flow by their response to the change in local metabolic conditions.

Animals↗
PubMed1997

Suppression of CO2-induced relaxation of bovine retinal pericytes by angiotensin II.

PURPOSE: To determine whether angiotensin II (Ang II), a vasoconstrictive peptide, changes the relaxation effect of elevated partial pressure of carbon dioxide (PCO2) on pericytes. METHODS: The contractile tone of cultured bovine retinal pericytes was measured when the ambient PCO2 was elevated in the absence or the presence of Ang II. All experiments were performed in the bicarbonate-buffered solution at 37 degrees C. RESULTS: Ang II (10(-6) M) by itself did not increase the baseline tone of the pericytes. Raising the PCO2 from 5% to 20% acidified the solution (pH dropped 0.51 +/- 0.02 U) and caused a sustained and statistically significant 22.9% +/- 4.6% relaxation of pericytes within 5 minutes (n = 8). In the presence of Ang II (10(-6) M), the maximum relaxation induced by 20% PCO2 was only 12.6% +/- 4.5% (n = 6) at 3 minutes, and the relaxation was not sustained. The effect of Ang II was statistically significant. Pretreatment with the competitive Ang II receptor antagonist saralasin (10(-6) M) for 10 minutes completely abolished the effect of Ang II (10(-6) M) on the response of pericytes to 20% PCO2. Saralasin by itself had no effect. CONCLUSIONS: Ang II attenuated the relaxing response of pericytes to elevated PCO2 through saralasin-sensitive Ang II receptors. Results suggest that some vasoactive agents, such as Ang II, could affect the pericyte responses to metabolic needs as signaled by local PCO2. This experimental design may permit further investigation of the altered physiology of local blood flow regulation.

Angiotensin II↗
PubMed1997

Adenosine-induced relaxation of cultured bovine retinal pericytes.

PURPOSE: To investigate the effect of adenosine on the contractile tone of cultured bovine retinal pericytes. METHODS: Changes in the contractile tone were quantified as the changes in the summed length of wrinkles induced by pericytes on the silicone surface on which the cells were grown. RESULTS: Adenosine at 10(-9) M had no effect. In the range of 10(-8) to 10(-4) M, adenosine caused relaxation of pericytes in a concentration-dependent manner. Complete relaxation was induced by 10(-5) M to 10(-4) M adenosine. The concentration of adenosine that produced 50% relaxation was 3 x 10(-7) M. At all concentrations, relaxation began within 1 minute, reached the maximum within 5 to 10 minutes, and persisted for at least 30 minutes. After a washout of 3 x 10(-7) M adenosine, the reduced contractile tone recovered to the original level in 10 minutes. The adenosine-induced relaxation (3 x 10(-7) M) was completely abolished in the presence of 8-phenyl theophylline (10(-5) M), a nonselective adenosine receptor antagonist. The selective A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) at 10(-6) M did not reduce the effect of adenosine (3 x 10(-7) M). Conversely, the selective A2 receptor antagonist CP-66,713 at 10(-8) M partially inhibited (and at 10(-7) M, completely inhibited) the relaxation induced by adenosine (3 x 10(-7) M). The adenosine receptor antagonists-8-phenyl theophylline (10(-5) M), DPCPX (10(-6) M), and CP-66,713 (10(-7) M) by themselves had no effect on the contractile tone of pericytes. CONCLUSIONS: Adenosine causes relaxation of pericytes through the activation of the adenosine A2 receptor. Adenosine, which accumulates under ischemic conditions, may help to regulate local capillary blood flow.

Adenosine↗
PubMed1997

[Determination of tissue chlorine, bromine and iodine concentrations in normal persons with neutron activation method].

Concentrations of chlorine (Cl), bromine (Br) and iodine (I) in heart, liver, spleen, lungs, muscle and hair of normal and healthy persons living in Beijing area were determined with neutron activation method. Results showed that Cl concentrations in variety of tissues, except for hair, were no significant difference. Cl concentration in muscle was slightly less than that in other tissues. Bromine concentrations in lungs and iodine in liver were the highest. Bromine concentration in human tissues was significantly lower in Beijing area than abroad, and iodine was only slightly less and without statistical significance. Furthermore, Cl, Br and I in four kinds of biological standard reference materials were determined, and their results conformed with the recommendation values.

Adult↗
PubMed1997

[Changes in contents of chromium, zinc and copper in the blood, liver and kidney of diabetic rats].

Contents of chromium, zinc and copper in the blood (or serum), liver and kidney of diabetic rats induced by streptozotocin were determined for three weeks by graphite stove and flame atom absorption spectrophotometry to study the changes in trace elements in diabetics. Results showed liver chromium level increased significantly and kidney chromium level lowered significantly in diabetic rats, as compared with normal ones. Zinc and copper in liver and kidney and serum copper also increased to various extent during three-week observation period. No changes in chromium, zinc and copper levels in blood (or serum), liver and kidney, with the course of the disease, were observed. But, contents of trace elements in rats correlated with their blood sugar levels closely, and chromium, zinc and copper contents in the liver correlated with those in the kidney directly, and with chromium content in the kidney inversely. Therefore, improvement of blood sugar level in diabetic rats may, to a certain extent, improve the disturbance of trace elements in the body.

Animals↗
PubMed1997

[Synthesis and characterization of biodegradable alpha,beta-poly (3-hydroxypropyl, propyl)-DL-asparamide].

A biodegradable condensation polymer alpha,beta-poly (3-hydroxypropyl, propyl)-DL-asparamide has been synthesized. Its monomer is DL-aspartic-acid and its spacers are mixture of 3-amino-propanol-1 and propylamine. The polymers thus synthesized are characterized by 1H-NMR, water sorption and intrinsic viscosity. For the purpose of applicability, we have synthesized the polymers with different properties in reference to the molar ratios of propyl amine to 3-amino-hydroxypropyl in polymer synthesis.

Aspartic Acid↗
PubMed1997

[Experimental study on effect of bushen shengjing decoction on kidney yang and testicular dysfunction in rats].

OBJECTIVE: To explore the therapeutical mechanism of Bushen Shengjing Decoction (BSSJD) in treating infertility. METHODS: Fed Wistar male rats with adenine 30 mg/100 g.d continuously for 30 days. The rats manifested the symptom which was similar to the human Kidney Yang Deficiency, the genitality dropped, the function of sperm-producing in the testis was disturbed, the contents of luteinizing hormone (LH), testosterone (T) and compound F (F) in blood were all lower than rats of normal group, P < 0.01. The model rats took the BSSJD 3 ml/100 g.d (each ml contains crude drugs 2 g) continuously for 10 days, interval for three days, then medicated again and total medication of BSSJD was 30 days. RESULTS: The symptom of Kidney Yang Deficiency in rats was improved obviously, the genitality, sperm quality and function of sperm producing in testis were all enhanced obviously, so did the hormone level of LH, T, F in blood. Comparing to untreated control group, the difference was significant (P < 0.05). CONCLUSION: BSSJD has the function of reinforcing Yang and replenishing essence and regulate the endocrinological function.

Adenine↗
PubMed1997

[Comparison between intraarterial pulsegraphy and thermodilution method for determination of cardiac output during anesthesia and operation in patients undergoing cardiac valve replacement].

Comparison of intraarterial pulsegraphy and standard thermodilution methods for determination of cardiac output (CO) in 14 patients with poor cardiac function following valve replacement operation was performed. The CO, cardiac index (CI) were moderate to high correlated between the two methods before and after valve replacement respectively. The study indicates that intraarterial pulsegraphy provides a continous method of determining CO in patients with poor cardiac function during operation.

Adult↗
PubMed1996

Cellular distribution of the NMDA receptor NR2A/2B subunits in the rat striatum.

Using immunohistochemical double-labeling with a specific antibody recognizing both NR2A and NR2B subunits, we studied the cellular distribution of the NMDA receptor subunit NR2A/2B on all major known striatal neuron types. Among striatal interneurons, our results showed that none of somatostatin interneurons was labeled for NR2A/2B subunits, 56% of parvalbumin interneurons were double-labeled for NR2A/2B, and all identified cholinergic interneurons were labeled for NR2A/2B. Among striatal projections neurons, 95% of striatonigral neurons, 96% of enkephalin-containing neurons, and 98% of calbindin-containing striatal matrix neurons were double-labeled for NR2A/2B. Our studies demonstrate that there is a differential distribution of the NMDA receptor NR2A/2B subunits on striatal neuron types. The paucity of NR2A/2B subunits on NMDA receptors on striatal somatostatin interneurons may confer resistance to NMDA receptor-mediated excitotoxicity on these neurons.

Acetylcholine↗
PubMed1996

Neural cell type-specific expression of QKI proteins is altered in quakingviable mutant mice.

qkI, a newly cloned gene lying immediately proximal to the deletion in the quakingviable mutation, is transcribed into three messages of 5, 6, and 7 kb. Antibodies raised to the unique carboxy peptides of the resulting QKI proteins reveal that, in the nervous system, all three QKI proteins are expressed strongly in myelin-forming cells and also in astrocytes. Interestingly, individual isoforms show distinct intracellular distributions: QKI-6 and QKI-7 are localized to perikaryal cytoplasm, whereas QKI-5 invariably is restricted to the nucleus, consistent with the predicted role of QKI as an RNA-binding protein. In quakingviable mutants, which display severe dysmyelination, QKI-6 and QKI-7 are absent exclusively from myelin-forming cells. By contrast, QKI-5 is absent only in oligodendrocytes of severely affected tracts. These observations implicate QKI proteins as regulators of myelination and reveal key insights into the mechanisms of dysmyelination in the quakingviable mutant.

Aging↗