Biomedical subjects

H Li

Publications and source records attributed to H Li.

At least 433 records · Page 24Linked to original sources

PubMed2001

[Clinical significance of c-myc oncogene amplification in primary hepatocellular carcinoma by interphase fluorescence in situ hybridization].

OBJECTIVE: To investigate the relationships between c-myc oncogene amplification in primary hepatocellular carcinoma (HCC) and its clinical prognosis. METHODS: To detect c-myc oncogene amplification in 100 cases with primary HCC and in 6 cases with satellite nodes by interphase fluorescence in situ hybridization (FISH). RESULTS: c-myc amplification was detected in 92 of 100 (92%) cases with HCC, 37 of which (37%) showed high copy amplification (HC), 55 (55%) low copy amplification (LC) and 8 (8%) single copy or no amplification (SC). There wasn't statistically different significance between the frequency of c-myc amplification and clinical stage and tumor size, and pathological types (P > 0.05), however, in the 90 follow-up resected cases, the one-year rates of recurrence in HC, LC and SC were 70.6% (24/34), 39.6% (19/48) and 12.5% (1/8) respectively (P < 0.05) but the recurrence rates after more than one year were 14.70% (5/34), 14.6% (7/48) and 0 (0/8) respectively (P > 0.05). Meanwhile, two-year survival rate of patients with HC was significantly lower in comparison with those with LC and SC (P = 0.001). CONCLUSIONS: There is a high frequency of c-myc oncogene amplification in primary HCC and the fact that the patients with HC showed poorer prognosis indicates that the level of c-myc oncogene amplification may be a sensitive index in the prognosis of HCC.

Adult↗

PubMed2001

[Activation of p38 and c-Jun NH2-terminal kinase mitogen-activated protein kinases in human prostate carcinoma cell lines with different metastatic potentials].

OBJECTIVE: To investigate the influence of P2 purinoceptor agonist ATP on p38 mitogen-activated protein kinases (MAPK) and JNK (c-Jun NH(2)-terminal kinase) signaling pathway in two human prostate cancer cell sublines (1E8 and 2B4) with different metastasis potentials. METHODS: Activated p38 and JNK were detected by Western blot with phospho-specific antibodies directed against the dually phosphorylated active forms of p38 or JNK. RESULTS: Exposure of 1E8 and 2B4 prostate cancer cells to ATP resulted in p38 activation in a concentration- and time-dependent manner. ATP-induced p38 activities were higher in metastatic 1E8 cells when compared with nonmetastatic 2B4 cells. JNK signaling pathway was not activated by ATP. An MEK inhibitor PD 98059 failed to inhibit ATP-induced p38 activation, while p38 inhibitor SB 203580 and P2 purinoceptor antagonist suramin effectively inhibited activation of p38, the inhibition rate being 1E8 83% and 79%, 2B4 81% and 69%. The response of ATP-stimulated p38 to G-protein modulator pertussis toxin in 1E8 and 2B4 cells was not obvious. CONCLUSIONS: p38 but not JNK signaling pathway can be activated by P2 purinoceptor agonist ATP. Differences of p38 activation by ATP are noted between metastatic 1E8 cells and non-metastatic 2B4 cells. These results provide instructive clues to cancer malignant growth and metastasis research.

Adenosine Triphosphate↗

PubMed2001

Serum antioxidant status of civil aircrew.

Objective. To study the serum antioxidant status in civil aircrew members who had more than 4000 h of cumulative flight hours, therefore exposed to a higher dose of cosmic radiation comparing to the dose received by ground residents. Method. Differences in the serum levels of total antioxidant capacity (TAOC), superoxide dismutase (SOD) and malondialdehyde (MDA) were investigated in 230 crew members, 37 local ground residents in Xinjiang, and 37 ground residents in Tianjin. Result. Significantly higher levels of all the three serum indexes were found in civil aircrew members. Serum levels of TAOC and SOD were higher in Xinjiang than in Tianjin ground residents, although no difference was found for MDA. Positive correlations were observed among the three serum indexes in this study. Conclusion. The elevated serum level of MDA in civil aircrew members deserves a proper attention by health care policy makers.

Adult↗

PubMed2001

[Study on apoptosis of human gastric adenocarcinoma cell SGC-7901 induced by aining in vitro and the cell cycle].

OBJECTIVE: To study the inducing apoptosis effect of Aining on human gastric adenocarcinoma cell in vitro. METHODS: Agarose gel electrophoresis (AGE) and flow cytometry (FMC) techniques were adopted to study the inducing apoptosis effect of Ainging on the human gastric adenocarcinoma cell. RESULTS: The human gastric adenocarcinoma cell's DNA was digested into fragments which gave rise to a characteristic "DNA Ladder" on agarose gel electrophoresis, while the percentage of apoptotic cells was 43.5%. But the blank group had neither DNA ladder, nor apoptotic peak. Cell cycle analysis showed that the proliferation index was 33.7% after the human gastric adenocarcinoma cells treated with Aining, and there was no cell phase specialty. CONCLUSION: Aining can induce human gastric adenocarcinoma cell apoptosis in vitro.

Adenocarcinoma↗

PubMed2001

[The prognostic value of vascular endothelial growth factor in breast cancer].

OBJECTIVE: To define the relevance of VEGF status to the prognosis of breast cancer. METHODS: The tissues of 70 invasive ductal breast carcinomas were evaluated for VEGF protein expression by immunohistochemistry LSAB method, and the prognostic value of VEGF status was assessed in combination with the follow-up data on those breast cancer patients. RESULTS: VEGF status was inversely correlated with relapse-free survival and overall survival. Kaplan-Merier survival curve showed that VEGF-rich tumor group had higher relapse rate and mortality rate. Multivariate regression analysis confirmed that the VEGF status had certain prognostic value, but it could not be considered as an independent prognostic indicator. CONCLUSION: VEGF status is one of the significant prognostic indicators of breast cancer.

Biomarkers, Tumor↗

PubMed2001

[Study of the changes and effect of VEGF and bFGF in early stage of maxillofacial blast injury in rabbits].

OBJECTIVE: The aim of this study is to determine the content of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in the wound fluid during maxillofacial soft tissue blast injury, and to evaluate their effects on angiogenesis of wound healing. METHODS: The rabbit model of maxillofacial blast injury was made by KTY-04 blasting cap. The content of VEGF and bFGF in wound fluid which was collected by using polying alcohol (PVA) sponge, were detected by ELISA. The distributions of VEGF and bFGF in the wound tissue were observed by using the techniques of in situ hybridization and immunohistochemistry. RESULTS: In the wound fluid of maxillofacial blast injury, the content of VEGF was rising steadily at the first week after injury. Comparing with natural sera, it showed difference from the first day after injury, and showed obvious different from the third day (P < 0.01), on which the content was 2.9 ng/ml +/- 2.7 ng/ml. It reached the peak on the seventh day after injury. The bFGF level in wound fluid was 565 pg/ml +/- 436 pg/ml, the peak value was gained at the sixth hour after injury. In the following days, it declined close to the serum level three to five days after injury, and then moved up slightly on the seventh day after injury. The expression of VEGF was located in epithelial cells, vascular endothelial cells and some chronic inflammatory cells. The mRNA transcription of bFGF was present in fibroblasts, endothelial cells and macrophages. CONCLUSION: VEGF and bFGF take part in two angiogenic cascades with synergistic action in maxillofacial blast injury. The bFGF stimulates the initial angiogenesis and induces the production of VEGF. The subsequent and more prolonged angiogenic stimuli can be mediated by VEGF.

Animals↗

PubMed2001

[Effects of clasp designs of Kennedy Class II RPD on the displacement of alveolar bone around the abutment tooth--an under load hologram study].

OBJECTIVE: This article is to investigate the effects of different clasp designs of Kennedy class II RPD on the displacement of alveolar bone around the abutment tooth. METHODS: This experiment was carried out by using a separate human mandible. Five clasp designs were examined in this experiment, including RPA, RPI, modified RPI (mRPI), three-arm clasps and buccal wrought wired three-arm clasps. Hologramatic measurement was applied to record the different effects of these five designs of clasps on buccal and lingual alveolar bone. RESULTS: The RPI clasp was found to cause the smallest bone displacement. Generally, the clasps with the mesial occlusal rest (RPA, RPI, mRPI) caused smaller bone displacements than those with distal occlusal rests. The bar clasps brought about evenly spread bony displacements, however, the circumferential clasp caused highly concentrated displacement around apical site of the abutment tooth. CONCLUSION: The results suggest that mesial occlusal rests and bar clasps are preferable designs in this kind of prostheses.

Alveolar Process↗

PubMed2001

[Expression of bcl-2 and Bax genes in facial neurons and their regulation of neuron apoptosis following facial neurotmesis in rats].

OBJECTIVE: The aim of this study is to investigate the relationship between the expression changes of bcl-2 and Bax genes and their functions in facial neuronal apoptosis after amputating the facial nerve. METHODS: Rats were randomized into two groups, including the experimental and the control group. The changes of expression of bcl-2 and Bax genes in the facial neurons and facial neuronal apoptosis were observed after the facial nerve amputation using the methods of ABC immunohistochemical staining and TUNEL. RESULTS: The expression of bcl-2 and Bax genes and the apoptosis of facial neurons were significantly higher in the experimental group than those of the control group from the 3rd to 21st day after amputation, but the bcl-2/Bax significantly decreased compared with that of the control group. CONCLUSION: This indicated that bcl-2 and Bax might play an important regulation role in the process of facial neurons apoptosis following facial nerve amputation.

Animals↗

PubMed2001

[The relationship between content of substance P, VIP in pharyngeal tissue and narrow pharyngeal cavity of patients with OSAS].

OBJECTIVE: To investigate the relationship between content of substance P, VIP in the pharyngeal tissue and narrow pharyngeal cavity of patients with OSAS. METHOD: By using semi-quantitative immunohistochemical method, resected pharyngeal tissue from 30 patients with OSAS and 12 normal health adult controls were investigated with rabbit anti-substance P and rabbit anti-VIP. RESULT: SP and VIP were detected in tribution within the epithelium or between epithelium cells, around the pharyngeal glands and gland ducts, around endothelium cells and smooth muscle of blood vessels. SP and VIP levels in pharyngeal tissue of the patients with OSAS were increased than those of the controls. CONCLUSION: Narrow of pharyngeal cavity with OSAS was relative to edema of pharyngeal tissue induced by increased SP and VIP in pharyngeal tissue. A neurogenic inflammation was one of the factors of OSAS.

Adult↗

PubMed2001

[Estimation of gas chromatographic retention index for polycyclic aromatic hydrocarbons using VMDE].

A novel molecular distance-edge vector with 6 parameters was calculated for 100 polycyclic aromatic hydrocarbons (PAHs) based on the molecular interaction theory. It was found that there was a good linear relationship between the molecular distance-edge vector (VMDE) and the gas chromatographic retention index for the 100 PAHs, and the molecular modelling equation for the quantitative structure-retention relationship (QSRR) can be expressed as follows: IR = a + b VMDE, n = 100, r = 0.988, where a and b represent regression coefficients. The regression results showed that the molecular distance-edge vector is in good agreement with the results of molecular polarizability index to the gas chromatographic retention index for the polycyclic aromatic hydrocarbons.

Air Pollutants↗

PubMed2001

[Expression of Th1, Th2-typed cytokines and its significance in nasal polyps].

OBJECTIVE: To evaluate the possible role of cytokines in pathophysiology and treatment of nasal polyps. METHOD: The expressions of Th1-typed cytokines IFN-gamma, IL-2, IL-12 and Th2-typed cytokines IL-4, IL-5, IL-8, IL-10, IL-13 were investigated with enzyme-linked immune sorbent assay(ELISA) in 25 patients with nasal polyps. RESULT: There was a significant upregulation of Th2-typed cytokines IL-4, IL-5, IL-8, IL-10, IL-13 in nasal polyps compared with normal nasal mucosa, especially IL-4 and IL-5 (3.9 times and 8.8 times higher than normal mucous respectively) while the expression of Th1-typed cytokines IFN-gamma, IL-2, IL-12 decreased after treated with local glucocorticoid. The levels of Th2-typed cytokines decreased significantly and Th1-typed cytokines had no obvious change. CONCLUSION: The upregulation of Th2-typed cytokines such as IL-4, IL-5, IL-8, IL-10, IL-12 may play an important role in the pathophysiology of nasal polyps and Th2-typed cytokines can be viewed as a target of treatment to nasal polyps.

Adolescent↗

PubMed2001

[The analysis of long-term curative effect in 201 cases of endoscopic sinus surgery].

OBJECTIVE: To analyze the long-term curative effect of endoscopic sinus surgery (ESS), and to study the factors related to the defeat of endoscopic sinus surgery. METHOD: 201 cases (353 sides) of chronic sinusitis and nasal polyps were treated with ESS, and were treated by taking the nasal cavity as a whole unit. RESULT: Following up survey from 12 months to 24 months postoperatively, it was found that 108 cases were cured (53.7%), 82 cases achieved symptomatic relief(40.8%), 11 cases remained failure (5.5%). CONCLUSION: It is very important to improve the ESS technique in order to reduce the recurrence of nasal polyps and sinusitis and to improve the curative effect of ESS, in addition, the treatment after operation is also indispensable to successful surgery.

Adolescent↗

PubMed2001

[Revision endoscopic sinus surgery on chronic sinusitis and polyps].

OBJECTIVE: To study the indications, surgical landmarks, surgical significance, complications and operative avoidance of revision endoscopic sinus surgery on chronic sinusitis and polyps. METHOD: We performed revision endoscopic sinus surgery on 112 cases of chronic sinusitis and polyps under controlled hypotension anaesthesia by using the Messerklinger technique and Stryker debrider. RESULT: 89 cases were successful and 17 unresolved, 6 failed, all the complications consist of cerebrospinal fistula in one, orbital hematoma in four, increased tearing in three and profuse bleeding in 6 patients. CONCLUSION: Revision endoscopic sinus surgery was advised in case of sinuous obstruction caused by uncontrolled lesions under postoperative care, which can do good for adhesion and obstruction except nasal polyposis. The remanet of the middle turbinate and the upper arch of choana were helpful operative landmarks. Preoperative CT scan decrease the complications.

Adolescent↗

PubMed2001

[Determination of volatile organic compounds in atmospheric environment].

It is well known that volatile organic compounds (VOCs) are the main photochemical pollutants and ozone precursors of the photochemical smog. Investigation of photochemical pollution in the ambient air must focus on VOCs, but the concentration of VOCs in ambient air is in a very low level (10(-9)-10(-12), volume fraction), so there are difficulties in the determination of VOCs. In this work, based on the TO14A and TO15 methods recommended by the Environmental Protection Agency of United States, an improved method for the determination of fifty-six VOCs, mainly O3 precursors, in atmospheric environment was developed. Operating conditions of VOCs preconcentrator, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were optimized. Air sample was first frozen by liquid nitrogen, and then H2O and CO2 were eliminated in the VOCs preconcentrator. The preconcentrated VOCs sample was injected to GC and detected by MS or hydrogen flame ionization detector (FID). The C2-C10 hydrocarbons were separated effectively in capillary columns under the high concentration of CO2. The detection limits were 0.1 microgram.m-3 and the relative standard deviations were in the range from 2.57% to 9.82%. This method has been used for the determination of VOCs in real samples. The results were satisfactory.

Air Pollutants↗

PubMed2001

[Biosynthesis of glutathione: construction of ATP regeneration system between recombinant E. coli and S. cerevisiae].

An ATP regeneration system between two microorganisms, in which recombinant E. coli II-1 and S. cerevisiae WSH-J702 were used as the biosynthesis enzymes source of glutathione and ATP, respectively, was constructed by using glucose as an energy substrate. Yeast cells after permeable treatment could hardly consume glucose. The glycolysis pathway of yeast was started by adding 1.0 mmol/L AMP and 0.05 mmol/L NADH simultaneously. GSH biosynthesis in the coupling system was improved with increasing glucose concentration to 400 mmol/L, where the concentration of GSH reached 10.4 mmol/L (3.2 g/L). Both the coupling system and the non-coupling system with ATP added could hardly produce GSH under the absence of magnesium. The low efficiency of ATP regeneration system constructed was probably caused by the chelation between magnesium and ATP. By adding magnesium to the coupling system, a final concentration of GSH, 14.3 mmol/L (4.4 g/L), was achieved at 6 h of reaction.

Adenosine Triphosphate↗

PubMed2001

[Construction of recombinant E. coli with high glutathione biosynthetic activity and the biosynthetic process].

A recombinant strain E. coli II-1, which exhibited high glutathione (GSH) biosynthetic activity and high stability, was constructed by transforming plasmid pGH501 which contains gene gsh I and gsh II into a wild type strain E. coli II. 4 g/L GSH accumulated extracellularly by using toluene-treated cell. In GSH biosynthetic system, GSH production was improved by increasing the concentration of L-glutamate, while inhibited by L-cysteine if it's concentration was beyond 20 mmol/L. In GSH biosynthetic reaction, the apparent little consumption of L-glutamate and glycine was concluded experimentally to be that toluene-treated E. coli II-1 cells still contained high concentration of L-glutamate and glycine. According to the change of energy cofactor in the GSH biosynthetic process, a possible GSH biosynthetic mechanism controlled by E. coli II-1, was proposed: the energy donator of reaction catalyzed by glutathione synthetase (GSH-II) was ADP but not ATP, the reaction was rate-limited step within the whole GSH biosynthetic process, high concentration of ADP might inhibit the activity of GSH-II. Further degradation of GSH was prevented by the addition of 100 mmol/L L-serine and potassium borate mixture. In such case, 23.0 mmol/L (about 7.1 g/L) GSH accumulated at 3 h.

Adenosine Diphosphate↗

PubMed2001

[Purification and some properties of D-hydantoinase produced by Pseudomonas 2262].

A D-hydantoinase produced by Pseudomonas 2262 was purified to electrophoretic homogeneity by the steps of thermal treatment, (NH4)2SO4 fractionation and column chromatography with Q-Sepharose fast flow, phenyl-Sepharose fast flow and Superose 12. Purification of about 60 fold was achieved with an overall yield of 16%. The relative molecular mass of the native enzyme is 109 kD and that of subunit is 53.7 kD by the analysis of Native and SDS-PAGE as well as gel filtration respectively. Some properties of the enzyme such as the sensitivity to thiol reagent and the effects of metal ions, for instance inhibited by Zn2+ and activited by Mn2+, Mg2+ are identical to dihydropyrimidinase. The optimum temperature and pH for enzymatic catalysis are 70 degrees C and 8.0 respectively. The enzyme activity is stable under 60 degrees C and in the pH range of 6-10. The N-terminal sequence for 10 amino acid residues is MDKLIKNGTI.

Amidohydrolases↗

PubMed2001

[Application of corepraxia in the implantation of intraocular lens].

PURPOSE: In the cases of aphakia or cataract which complicated with iridosteresis, corectasis and pupil displacement, corepraxia was performed when implanting intraocular lens (IOL) in order to recover the normal shape and position of pupil, improve postoperative visual acuity and prevent monodiplopia and glare. METHODS: In the cases which have iridosteresis at the direction of 9-3 oclock or updrawn pupil, iris suture was performed at the incision directly(open method); while those at the direction of 3-9 o'clock, operation was performed outside the anterior chamber (close method). RESULTS: In 22 cases, the percentage which having visual acuity better than 0.5 is 65%, having nearly round shape pupil 67%, having pupil diameter less than 3 mm 73%, having normal pupil position 67%. CONCLUSION: All kinds of deformed pupil can be recovered to their normal shape, size and position by performing corepraxia while IOL was implanted. The prolene has light reaction and better effect in iris suture.

Adolescent↗