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Biomedical subjects

X Liang

Publications and source records attributed to X Liang.

At least 163 records · Page 9Linked to original sources
PubMed1998

[Apolipoprotein(a) and cortical cerebral infarction].

OBJECTIVE: To elucidate the correlation of apolipoprotein(a)[apo(a)] with cerebral infarction at the level of molecule and protein. METHODS: The serum Lp(a) level, by means of ELISA, the polymorphism of apo(a) protein, by SDS-PAGE/Western blotting combined with silver staining assays, and the sequence polymorphism in 5' control region, the first exon and intron of apo(a) gene, by PCR-SSCP/AFLP assays, were detected in 85 healthy controls and 42 cases of cortical cerebral infarction. RESULTS: The serum Lp(a) level was remarkadly higher in the patients (153 +/- 3 mg/L) than that in the controls(56 +/- 4 mg/L) (t = 4.15, P < 0.001), even in the subjects with the same apo(a) phenotype. The allele frequency of low molecular weight phenotype containing B, S1 and S2 isoforms was also significantly higher in the patients than that in the controls (0.5238 vs. 0.2941). There were 2 sites of sequence variance in the 5' control region of apo(a) gene in the studied population, which were of significant difference between the patients and controls, and were related to the variation of serum Lp(a) level. CONCLUSION: On the basis of proving further the risk of high serum Lp(a) level for AS event, we found that the low molecular weight phenotype of apo(a) is closely associated with cerebral infarction. The variation of serum Lp(a) level is also related to the sequence of apo(a) gene, indicating that both the size and sequence of apo(a) are associated with the susceptibility to cerebral infarction due to its impact on serum Lp(a) level.

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PubMed1998

Effects of beta-amyloid peptide on transient outward potassium current of acutely dissociated hippocampal neurons in CA1 sector in rats.

OBJECTIVE: To explore the mechanism of beta-amyloid peptide (beta-AP) in Alzheimer's disease at ionic channel level. METHODS: Hippocampal CA1 neurons of 7-21 days' rats were acutely dissociated and the effects of beta-AP on transient outward potassium current were observed by a whole-cell recording patch clamp technique. RESULTS: beta-AP can significantly block transient potassium current in dose-dependent, time-dependent and partly voltage-dependent manners. CONCLUSION: beta-AP may decrease the membrane conductance of K+ channels in hippocampal neurons, playing an important role in the pathophysiological mechanism of Alzheimer's disease.

Amyloid beta-Peptides↗
PubMed1998

[Examination of eustachian tube function in chronic suppurative otitis media].

Discussing something about the methods of examining the eustachian tube function of chronic suppurative otitis media. The examination of the eustachian tube function were given on 96 cases of chronic suppurative otitis media with Valsalva method, tympanium drip and acoustic impedance method. Though the former two methods were imperfect, the combination of them was similar to the acoustic impedance method in outcome, which is easy and convenient and doesn't need expensive instrument. The combination of the former two methods in result could get rid of the imperfection of each of them and could evaluate the eustachian tube function in accuracy, which is fit for basic-level hospital.

Acoustic Impedance Tests↗
PubMed1998

[Cervical necrotizing fasciitis].

Necrotizing fasciitis is a severe fatal soft tissue infection characterized by necrosis of fascia. It was caused by polymicrobial infections with aerobe and anaerobe. Although it commonly involved abdomen, extremities and perineum, it might also occur in head and neck. One case of CNF arising from pharyngolaryngitis was reported. A review of the literature with the clinical presentations, bacteriology, diagnosis and treatment was presented. The key to successful management is early recognition, broad-spectrum antibiotics and prompt aggressive surgical intervention with medical support and hyperbaric oxygen therapy.

Fasciitis, Necrotizing↗
PubMed1998

[Effects of Chinese herbs xianzhen tablet on the deformability of erythrocyte in non-insulin-dependent diabetes mellitus patients with deficiency of both qi and yin and deficiency of kidney with blood stasis].

OBJECTIVE: To explore the effects of Xianzhen Tablet (XZT) on the hemorheology of type 2 diabetes (NIDDM) on the basis of previous studies in XZT, that have indicated its ability to deplete fasting blood glucose, to reduce the injury of free radical to the body, to improve the Na(+)-K(+)-ATPase in the erythrocyte membrane of NIDDM. METHODS: Erythrocyte deformability and aggregation were studied with Ektacytometer in a total of 60 type 2 diabetes who were randomly divided into two groups. One was ZXT treated group, another was placebo group. RESULTS: (1) The erythrocyte deformability of type 2 diabetes was lower than that in normal subjects (P < 0.001), but the erythrocyte aggregation increased abnormally than that of health people (P < 0.001). The correlation test indicated there were negative correlation with plasma fibronogen and positive correlation with blood cholesterol (P < 0.05). (2) The erythrocyte deformability in the ZXT treated group with 30 patients improved after 8 weeks treatment (P < 0.01), with the decreased fasting blood glucose and plasma fibrinogen (P < 0.05). Compared with placebo group, there was significant statistical difference (P < 0.01). CONCLUSIONS: XZT could improve the erythrocyte deformability in the type 2 diabetes.

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PubMed1998

[Preliminary study on the correlation between neovasculature and metastatic nasopharyngeal carcinoma by computer image analysis].

OBJECTIVE: To investigate the significance of neoangiogenesis in metastasis of nasopharyngeal carcinoma (NPC) so as to clarify further the role of neovascularity in evaluating the prognosis of NPC and the probability of antiangiogenesis in preventing distant metastasis of NPC. METHODS: Fifty-two patients with metastatic NPC were selected and strictly matched in sex, age, T stage, and N stage with another 52 patients with non-metastatic NPC and survived a long time. The tumor tissues of all 104 patients were retrived for computer-assisted, immunohistochemical analysis of tumor vasculature. RESULTS: Counts of microvessel and relative area of all microvessels per image were significantly higher in metastatic NPCs than those of curable, non-metastatic NPCs; while average area of microvessel and average perimeter of microvessel in metastatic NPCs were smaller than those of the opposite. No significant difference in any microvessel parameter had been found among various types of metastasis. CONCLUSIONS: The alterations of microvessel parameters bore significant relationships with metastases of NPC. Evaluation of neovascularity with computer image analysis may help in estimating the prognosis of NPC and in finding out the indications for aggressive multimodal treatments. Angiogenesis inhibitors might be helpful in preventing NPC from distant metastasis.

Adult↗
PubMed1998

[Synthesis and biological activity of 2,3-benzopyrone analogs].

Several 2, 3-benzopyrone analogs were synthesized for evaluating their K(+)-channel and anticancer activities. The Friedel-Crafts reaction was taken place with some replacement phenyl acetic acid or its methyl ester and vanillin as reactants in the condition of Ac2O/ZnCl2. All products were confirmed by means of MS and 1H, 13CNMR spectra. Compounds 2 and 3 showed obvious activities on the K(+)-channel and anticancer screening, while the activity of compound 5 was weak. Compound 4 was not yet tested. The primary result indicate that the potential activity of such compounds deserves further study.

Antineoplastic Agents↗
PubMed1998

[Synthesis and structure-activity relationships of novel 14 beta-side chain taxol derivatives].

In order to develop new generation of taxol-like anticancer agents with fewer side effects, improved activity, superior pharmacological properties and broad antitumor spectrum, along with structure-activity relationship study, a series of new taxol derivatives are to be synthesized starting from sinenxan A--a biosynthetic taxane. Eight new 14 beta-side chain taxol derivatives with 4-OH and 4-Ac were synthesized in 5 and 6 steps from semisynthetic taxoid intermediate 7, respectively. These included taxol derivatives modified at C-2 position with benzoate, m-Cl benzoate, valerate and phenylacetate. All target compounds together with two other 14 beta-side chain taxol derivatives were tested in a microtubule assembly assay, and in an in vitro cytotoxicity assay (KB, A2780, HCT-8 cell line). All compounds had no effect in the microtubule assembly assay at 10 mumol.L-1. Most of them showed marginal activity in the in vitro cytotoxicity. The structure-activity relationship was different from taxol derivatives. 2-Aliphatic ester displayed similar activity to 2-aromatic ester, which indicated that the aromatic group at C-2 position was not important for cytotoxicity. Comparing among themselves, 4-OH derivatives possessed stronger activity than 4-Ac.

Antineoplastic Agents, Phytogenic↗
PubMed1998

[Synthesis and cytotoxicity of the new taxoids].

Sinenxan A is a new biosynthetic taxane. In order to search for new taxol analogues with cytotoxicity, sinenxan A was modified and studied. Ten new taxoids containing the tetrahydrofuran ring were esterified at C14 or C10 positions with taxol/taxotere side chain. Preliminary pharmacological tests showed that some of the compounds have certain cytotoxicity on KB, HCT-8 and A2780. Meanwhile, the relationship between their structures and activity was discussed.

Antineoplastic Agents, Phytogenic↗
PubMed1998

[Synthesis and antiulcer activity of 3,4-dihydro-hainanensine analogs].

In order to search for new compounds with new mode of action, high antiulcer activity and lower toxicity, 26(13 pairs of diastereoisomer A and B) 3,4-dihydro-hananensine analogs were synthesized. All compounds were tested in M1 receptor combined assay and gastric ulcer induced by cold-immersion stress in rats. Most compounds showed antiulcer activity, among them IX3A, IX7A, IX8A, IX12A, IX12B and IX13A exhibited more potent antiulcer activity than the control compound cimetidine. Meanwhile, the relationship between their structures and activity was discussed.

Animals↗
PubMed1998

[Studies on structure modification and structure-activity relationship of new taxoids derived from sinenxan a].

In order to develop new taxol analogues with possible antitumor properties, sinenxan A (SIA), a new biosynthetic taxoid, was chemically modified, mainly by esterification of C14-OH with taxol-like side-chain acids. Twenty-one new taxoids thus formed were tested on three kinds of cell lines. Their activities are far below those of taxol. The SAR of SIA derivatives partly agree with that of taxol and can be roughly discerned.

Antineoplastic Agents, Phytogenic↗
PubMed1998

[Thrombolysis by staphylokinase in rabbits with experimental pulmonary embolus].

Thrombolysis effect of recombinant staphylokinase (rSaK) developed in China was evaluated in rabbits with experimental pulmonary embolus model. 125I-labeled human fibrin blood clot was prepared in vitro and was injected through jugular vein resulting in a pulmonary embolus. Twenty thousands AU.kg-1(rSaK-H) or 5000 AU.kg-1(rSaK-L) of rSaK was infused in 0.5 h at constant rate by a peristaltic 20,000 U.kg-1. Another 20,000 AU.kg-1 of rSaK was infused within 2.5 h(rSaK-2.5 h). The residual labeled blood clot in lungs were found to be 62% +/- 11% (rSaK-H), 78% +/- 7% (rSaK-L), 92% +/- 7% (NS), 60% +/- 13% (SK), and 64% +/- 16% (rSaK-2.5 h). 125I-labeled degradation products in blood and urine were also statistically higher in thrombolytic agents treated group than those in NS controls. The results suggest that the thrombolytic effect of rSaK was determined by total dose and not determined by infusion time. Two of seven rabbits in the rSaK 2.5 h infusion group, the bleeding time was prolonged to more than 10 minutes while no prolongation was seen in rSaK high dose group. The clot lysis curves were very similar in 0.5 h or 2.5 h treatment of rSAK in vitro. Michaelis-Menten kinetics studies in vitro revealed that the Kms of rSaK and SK were almost the same, while a higher maximal velocity(34 kBq.min-1) was observed in rSaK than that in SK (10 kBq.min-1).

Animals↗
PubMed1998

[Analysis of oscillatory potentials of flectroretinogram].

This study presents a method for the analysis of oscillatory potentials (OPs) of electroretinogram (ERG) in frequency domain and time domain. OPs from 9 cases (9 eyes) of branch retinal vein occlusion, 9 cases (9 eyes) of central retinal vein occlusion and 40 normal control eyes were tested. The frequency spectra of the OPs were derived through Fast Fourier Transform. The mean frequency spectra, the total power, the maximum magnitude, the maximum power and the dominant frequency in frequency domain of the OPs were calculated. The OPs waveforms were re-constructed with the OPs frequency spectra data by counter-Fast Fourier Transform. In time domain, the latencies, the amplitudes and the sum of the amplitudes of the four peaks of OPs were measured.

Electrophysiology↗
PubMed1998

[Stability of HA-coated titanium implants used as orthodontic anchorage].

12 two-stage HA-coated titanium implants were inserted into the mandibular alveolar bones of two dogs were loaded with orthodontic force of 150 gram for 3 months. The stability of the implants under orthodontic force were studied with intraoral and radiographic examinations. The results showed that both intraoral and radiographic analysis were reliable for assessing implant stability, and no signs of fixture dislocation were found during the force application period (P > 0.05), while the abutment was tilted after being loaded for 2 to 3 months. This suggests that HA-coated titanium implants remain stable enough under orthodontic force and are suitable as anchorage for short-term orthodontic therapy after design of the implant neck is improved.

Animals↗
PubMed1998

[Preliminary study on HA-coated titanium implants used as anchorage for protraction of dog molar teeth].

HA-coated titanium implants were placed surgically into dog mandible to protract the mandibular second molars with an orthodontic force of 150 g. During the force application period of 3 months, the movement of the molars was tested periodically and relevant reasons of movement were analysed. The results showed that the mesial moving distances of the second molar were respectively 1.04 mm, 1.68 mm and 1.76 mm at the first, second and third month, and the main reason of tooth mobility was ascribed to the implant anchorage. It can be concluded tiat HA-coated titanium implant can be used as anchorage for moving and fixing posterior teeth in the orthodontic treatment.

Animals↗
PubMed1998

[Assessment of marginal tissue around HA-coated titanium implants for orthodontic anchorage in dogs].

12 two-stage HA-coated titanium implants placed in dogs' mandibles were loaded with an orthodontic force of 150 g for 3 month. Gingival bleeding index, plague and calcucus index, mobility index, probing depth and marginal bone were investigated. The results showed that the implants were stable and peri-implant soft tissue displayed slight inflammation, but no marginal bone absorption and no difference of bone quantity between the tension side and compression side were found. It can be concluded that the clinical trials of marginal tissue around the HA-coated titanium implants are satisfactory when the implants are used as anchorage for short-term orthodontic treatment.

Animals↗
PubMed1998

Analysis of oscillatory potentials of flash electroretinogram in frequency domain and time domain in retinal vein occlusion.

PURPOSE: To analyse the parameters of frequency domain and time domain of the OPs in branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). METHODS: OPs from 9 eyes of BRVO, 9 eyes of CRVO and 40 normal control eyes were tested. The frequency spectra of the OPs were derived through Fast Fourier Transform (FFT). The mean frequency spectra, the total power, the maximum magnitude, the maximum power and the dominant frequency in frequency domain of the OPs from the eyes of BRVO, CRVO and the normal control group were compared with each other. The OPs waveforms were reconstructed with the OPs frequency spectra data by counter-FFT. In time domain, the latencies, the amplitudes and the sum of the amplitudes of the four wavelets of OPs were measured and compared in the above subjects. RESULTS: There were no statistically significant differences in the magnitudes of frequency spectra, the total power, the maximum magnitude and the maximum power in the frequency range from 110 to 250 Hz between BRVO and normal subjects. However, in BRVO, the dominant frequency decreased significantly, the latencies of the first to the third OPs wavelet prolonged significantly, the amplitudes of the first and the second OPs wavelet and the summed amplitude of the four OPs wavelets attenuated significantly. Comparing the results of CRVO with those of normal subjects, there were statistically significant decrease in the magnitudes of frequency spectra from 150 to 180 Hz, there were statistically significant decrease in the total power, the maximum magnitude, the maximum power and the dominant frequency in the frequency range from 110 to 250 Hz, the latencies of the first to the fourth OPs wavelet prolonged significantly, the amplitudes of the first to the third OPs wavelet and the summed amplitude of the four OPs wavelets attenuated significantly. CONCLUSION: Some parameters of OPs in frequency domain and time domain are abnormal in branch retinal vein occlusion and in central retinal vein occlusion, which is more marked in the latter.

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