Search PubMed⌕ Search

Biomedical subjects

Y Liang

Publications and source records attributed to Y Liang.

At least 235 records · Page 13Linked to original sources
PubMed1998

Blocking effects of phentolamine on L-type calcium current and ATP-sensitive potassium current in guinea pig ventricular myocytes.

AIM: To study the effect of phentolamine on L-type calcium currents (ICa) and ATP-sensitive K+ currents (IK,ATP) in ventricular myocytes. METHODS: ICa and IK,ATP were observed using patch clamp techniques in whole-cell recording configuration. RESULTS: Phentolamine reduced ICa of ventricular myocytes in concentration-dependent and voltage-independent manners. Phentolamine 5, 25, and 100 mumol.L-1 decreased ICa from 370 +/- 99 nA to 310 +/- 95 nA (17% block, n = 6, P < 0.01), from 230 +/- 98 nA to 180 +/- 73 nA (23% block, n = 5, P < 0.05), and from 293 +/- 66 nA to 206 +/- 44 nA (30% block, n = 5, P < 0.01), respectively, without affecting the current-voltage relationship. Prazosin 100 mumol.L-1 and yohimbine 100 mumol.L-1, which were specific blockers of alpha 1 and alpha 2 adrenoceptors respectively, did not show the inhibitory effect on ICa. Phentolamine 100 mumol.L-1 also inhibited the IK,ATP induced by 2, 4-dinitrophenol (DNP) at 0 mV from 3.2 +/- 0.6 nA to 0.8 +/- 0.5 nA (75% block, n = 4, P < 0.01). CONCLUSION: Phentolamine directly inhibits ICa and IK,ATP in guinea pig ventricular myocytes.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1998

[Clinical analysis of intracranial venous embolism during pregnancy and puerperium].

OBJECTIVE: To study the cause and clinical manifestation of intracranial venous embolim during pregnancy and puerperium, and its early diagnosis and treatment. METHODS: 18 cases of intracranial venous embolism confirmed by Computed Tomography (CT) were eligible for this retrospective study. RESULTS: Of all the cases, 8 cases occurred before delivery and 10 post partum; 10 cases complicated by pregnancy induced hypertension and 8 cases postpartum hemorrhage. Headache occurred most frequently, followed by coma and seizure. Blood rheologic assay showed hypercoagulable states in 6 cases. For 11 cases treated with urokinase, 10 were cured, while in the remaining patients, 3 of 6 cured. CONCLUSIONS: The results show that hypercoagulability states were related to intracranial venous embolism. Coma and seizure were the main characters. CT was an important diagnostic measure. Lowering intracranial pressure, anticoagulation, dethrombosis and timely ending pregnancy were the main treatment measures. The early use of urokinase may exert better effect.

Adult↗
PubMed1998

U-74389G suppresses lipid peroxidation and apoptosis following focal cerebral ischemia and reperfusion in rats.

OBJECTIVE: To study the antioxidant and antiapoptotic effects of U-74389G on ischemic brain in rats. METHODS: Right focal cerebral ischemia and reperfusion was induced by suturing in 103 male SD rats weighing 280-310 g. To determine LPO in the cortex and striatum, we randomly divided 78 rats into 5 groups: group 1, sham-operative group (6 rats); group 2, control (18); group 3, U-74389G administration before ischemia (18); group 4, U-74389G administration before reperfusion; group 5, CS-4 vehicle as negative control. Groups 2-5 were further divided into 3 subgroups according to the duration of reperfusion. Another 25 rats were similarly grouped (5) to detect apoptosis with TUNEL stain. RESULTS: The concentrations of MDA in groups 3 and 4 were reduced and the activities of SOD and concentrations of GSH were partially restored as compared with the control group. These effects were more significant in group 3 than in group 4. Otherwise, CS-4 can not provide protective effects. The number of apoptotic cells in groups 3 (P < 0.01) and 4 (P < 0.05) was significantly reduced as compared with the control group. CONCLUSIONS: U-74389G has antioxidant and antiapoptotic effects on ischemic brain in rats. The administration of U-74389G before the onset of ischemia was more useful than that before the onset of reperfusion.

Animals↗
PubMed1998

[Determination of normal values and analysis of their relation for distortion product otoacoustic emission in guinea pigs].

In the present paper, we measured systematically the normal values of 1, 2, 4, 6 kHz distortion product otoacoustic emission (DPOAE) in guinea pigs and analyzed the relation of these values. The incidence of DPOAE in all frequencies were 100%. The amplitudes of DPOAE above 2 kHz were large than 25 dB SPL, but the amplitude of 1 kHz was lower than one of above 2 kHz. The threshold of above 2 kHz were lower than one of 1 kHz. A trend was found that latencies of all frequencies decreases accompanied with the f2 frequencies increasing. I/0 function curves demonstrated that there was a significant relation between the amplitudes of DPOAE and the levels of primary stimuli in the statistics, that is, lower levels of primary stimuli and smaller amplitudes of DPOAE. Our results indicated that a guinea pig, whose DPOAE possessed the properties of high incidence, large amplitude and stable responsibility, was an appropriate experimental animal for studying DPOAE. In addition, this paper recommended briefly the experience about the measuring techniques for DPOAE in guinea pigs.

Acoustic Stimulation↗
PubMed1998

[Changes of nitric oxide synthase in hypoxic pulmonary hypertension and the effect of L-arg and L-NAME on pulmonary circulation].

OBJECTIVE: To study the role of nitric oxide (NO) in Hypoxic pulmonary hypertension (HPH). METHODS: NADPH-d and immunohistochemistry were used to study the expression and localization of constructive and inducible nitric oxide synthase (cNOS iNOS) in the lungs of normoxia and HPH rats, at the same time, the effects of L-arginine (L-arg) and nitro-L-arginine-methyl-ester (L-NAME) on normoxic and hypoxic pulmonary circulation were investigated. RESULTS: NADPH-d positive expression was detected in the endothelium and smooth muscle cells (SMC) of large pulmonary vessels (PV) and in the epithelium and SMC of bronchi in the HPH group, but negative in the endothelium and SMC of small PV in normoxia. Hypoxia not only inhibited the expression of cNOS in the endothelium and SMC of PV and epithelium of bronchi, but also induced the expression of iNOS in the endothelium and SMC of PV and SMC of bronchi. Administration of L-NAME in normoxia had no effect on pulmonary circulation. The effect of administration of L-arg and L-NAME in hypoxia on right ventricular hypertrophy and remodeling of PV had no significance, compared with simple hypoxia. CONCLUSION: The inhibition of cNOS may contribute to the occurrence of HPH, but induced iNOS may depress the development of HPH.

Animals↗
PubMed1998

[A model for exercise-induced asthma in guinea pigs with lipopolysaccharide and metyrapone].

OBJECTIVE: To investigate the relationship between airway inflammation and exercise-induced asthma (EIA), an experimental model for EIA in guinea pigs was developed. METHOD: 27 guinea pigs was divided into 4 groups. A) LPS + MET exercise group (n = 7) had been pretreated with lipopolysaccharide (LPS 1 mg/kg, i.p.) and metyrapone (MET 50 mg/kg, i.p.) on the first day. Then lung resistance (RL) and dynamic compliance (Cdyn) were measured before and after exercise on the fourth day. B) LPS + MET non exercise group (n = 6) that pretreated with LPS and MET had nonexercise on the 4th day. C) NS exercise group (n = 7) pretreated with normal saline (NS 1 mg/kg, i.p.) on the 1st day. RL and Cdyn were measured before and after exercise on the 4th day. D) NS nonexercise group (n = 7) that pretreated with NS had no exercise on the 4th day. RESULT: In LPS+MET exercise group RL increased and Cdyn reduced significantly after exercise. In another 3 control groups there were no such changes either in RL or in Cdyn. CONCLUSION: These observations suggest that the treatment with LPS and MET could make a model for exercise-induced asthma.

Airway Resistance↗
PubMed1998

[Clinical study on treatment of moderate and advanced stage cancers by Bailong Tablets combined with chemotherapy].

OBJECTIVE: To assess the effects and mechanism of Bailong Tablet combined chemotherapy treatment. METHODS: The test group, 41 cancer patients of moderate and advanced stage treated by chemotherapy plus Bailong tablet, and the control group, 22 cancer patients treated by chemotherapy alone. Observe the chemotherapy complete rates (CCR) and the immunological function of the cell in the two groups. RESULTS: The CCR in the test group (92.6%) were higher than that of the control group (77.2%, P < 0.05). However, the toxic side-effect caused by chemotherapy in the test group were lower than that in the control group (P < 0.05). CD3 and the ratio of CD4/CD8 were obviously raised in the test group. The results indicates that the Bailong Tablets had the effects of regulating the immunological function of the T-cell. CONCLUSIONS: Bailong tablet could enhance the efficacy and reduce the toxic side-effect of chemotherapy. Modulation of the cell immunological function is possibly its mechanism.

Adjuvants, Immunologic↗
PubMed1998

[Study on the pathological features of airway inflammation in asthma and chronic bronchitis].

OBJECTIVE: To explore the difference between the pathological features of asthma and chronic bronchitis on airway inflammation, then to provide pathomorphological basis for appropriate diagnosis and treatment of these two different entities. METHOD: To compare the pathological changes of airways from 14 asthmatic and 13 chronic bronchitic patients. RESULT: There were damaging lesions shown on tracheo-bronchial epithelium of asthmatic and chronic bronchitic patients; various inflammatory cells and structural pathological changes occurred in submucosa. The numbers of eosinophilic cells and mast cells in asthmatic group were higher than those of chronic bronchitic group (P < 0.01). Thickness of basement membrane in early stage (P < 0.05) and thickness of smooth muscle were characteristic pathological changes for asthmatic group. Degranulation phenomenon of mast cells was found in asthmatic group. The pathological features of airway mucosa of chronic bronchitic group were different: eosinophilic cells < 1.2/HP and mast cells < 1/HP; no degranulation of mast cells was observed under electronmicroscopy. CONCLUSION: Both asthma and chronic bronchitis (including chronic asthmatic bronchitis) are chronic airway inflammatory illnesses, but obvious pathomorphological difference was found in their airway mucosa. These are two different diseases and the reasons for causing airflow obstruction are also different.

Adult↗
PubMed1998

[Percutaneous autogenous bone marrow grafting for repairing bone defect: an experimental study in rabbits].

OBJECTIVE: To observe osteogenesis of percutaneous autogenous bone marrow into cicatrix of bone defect. METHODS: 18 rabbits were used to observe the osteogenesis of percutaneous autogenous bone marrow into cicatrix of bone defect. A 1 cm bone defect model was made in each side of the radius. And 2 ml autogenous bone marrow was injected in the right radial bone defect after 6 weeks, and 2 ml peripheral blood in the left side. The animals were sacrificed in 1, 2, 3, 4, 12 weeks after injection. Bone formation was studied with histologic technique, X-ray examination and Ca-P quantitative estimates. RESULTS: After 1 week of injection, a big shadow of softtissue was found around the bone defect in the right side(bone marrow). Histologically a lot of new cartilage like tissues were found. In the left side(peripheral blood), no change was seen. After 4 weeks of injection, many of new bone-like shadows were observed around the defect by X-ray examination in the right side. The defect was smaller(average 1.5 mm) and bone formation was found. But in the left side, no signs for osteogenesis were noted. In 12 weeks defect was smaller(average 1 mm). Histologic sections proved well-developed bone tissue. In the left side, no bone formation found. CONCLUSION: Autogenous bone marrow can induce osteogenesis in cicatric bone defect, whereas no osteogenesis is found in the peripheral blood injection side.

Animals↗
PubMed1998

[Parameters of arterial occlusion during intracranial aneurysm surgery].

OBJECTIVE: To evaluate parameters, owing to temporary and/or permanent intraoperative arterial occlusion, could be related to the postoperative development of ischemic injury. METHOD: During 3-year period between October 1994 and March 1997, 27 patients with intracranial aneurysm were operated on with the aid of temporary and/or permanent arterial occlusion. Continuous intraoperative monitoring lCBF of the territories undergoing occlusion was carried out using LDF. Univariate analysis was used to study the relationship between the study variable and cerebral infarction. These variables included patient age, sexuality, aneurysm size, preoperative Hunt and Hess grades, LDF baseline value, LDF value following arterial occlusion and release of occlusion, the duration of arterial occlusion, the numbers of occlusive episodes, and the degree of arterial occlusion. Student's t-test was used for comparison of continuous variable such as age, and chi-square analysis was used to test the association of categorical variables. RESULT: The LDF value following arterial occlusion or residual lCBF, the duration of arterial occlusion, the numbers of occlusive episodes, and the occlusive degree were found to be significantly related to the postoperative development of ischemic injury. CONCLUSION: The residual lCBF and collateral circulation following arterial occlusion can be evaluated using LDF monitoring. When residual lCBF is more than 50 per cent of the baseline and the duration of arterial occlusion less than 20 minutes, temporary arterial occlusion is safe and does not develop postoperative ischemic injury.

Adolescent↗
PubMed1998

[Effects of tripterygium wilfordii polyglyco - sidium on intraocular inflammatory reaction after intraocular lens implantation].

OBJECTIVE: The effects of tripterygium wilfordii polyglyco - sidium (TWP) on intraocular inflammatory reaction after extracapsular cataract extraction and intraocular lens (IOL) implantation were studied. METHODS: 120 cases with senile cataract were divided into two groups: (1) Patients received TWP after IOL implantation; (2) patients received prednisone after IOL implantation. The slit - lamp was used to observe inflammatory cells and fibrinous exudate in the aqueous humor and cellular deposits on IOL on the 1st, 3rd, 7th and 14th postoperative days. RESULTS: The study indicated that on the 1st, 3rd, 7th and 14th postoperative days the inflammatory cells and fibrinous exudate in the aqueous humor and cellular deposits on IOL were significantly lower in TWP - treated group than that in steroid - treated group (P < 0.05). CONCLUSIONS: TWP is effective in reducing postoperative anterior ocular inflammation after extracapsular cataract extraction and IOL implantation. The TWP is more effective than the steroid in suppressing postoperative intraocular inflammatory reaction.

Aged↗
PubMed1998

Dendritic mast cells in the human nasal mucosa.

Human mast cells can be divided into two subtypes: MCTC cells, which contain tryptase and chymase, and MCT cells, which contain tryptase only. Herein we have used a combination of histamine, tryptase and chymase immunohistochemistry as a novel approach to the study of mast cells. Using this technique, we have discovered a new type of MCTC mast cell in biopsies of the nasal mucosa from healthy subjects and allergic patients. These mast cells have histamine-positive, dendrite-like cellular processes. Some cells have only one slender process, whereas other cells have several long processes extending from different parts of the cell body. Some of the cellular processes divide into two or three terminal branches, and histamine is sometimes found in small swellings along the course of the processes. Our findings contribute new aspects to the concept of mast cell heterogeneity. Thus, human mast cells may vary not only with respect to mediator content, but also with respect to gross morphologic features such as the presence of dendrite-like cellular processes. The recognition of this extreme heterogeneity may be an important step toward a better understanding of mast cell biology.

Adult↗
PubMed1997

Glypican and biglycan in the nuclei of neurons and glioma cells: presence of functional nuclear localization signals and dynamic changes in glypican during the cell cycle.

We have investigated the expression patterns and subcellular localization in nervous tissue of glypican, a major glycosylphosphatidylinositol-anchored heparan sulfate proteoglycan that is predominantly synthesized by neurons, and of biglycan, a small, leucine-rich chondroitin sulfate proteoglycan. By laser scanning confocal microscopy of rat central nervous tissue and C6 glioma cells, we found that a significant portion of the glypican and biglycan immunoreactivity colocalized with nuclear staining by propidium iodide and was also seen in isolated nuclei. In certain regions, staining was selective, insofar as glypican and biglycan immunoreactivity in the nucleus was seen predominantly in a subpopulation of large spinal cord neurons. The amino acid sequences of both proteoglycans contain potential nuclear localization signals, and these were demonstrated to be functional based on their ability to target beta-galactosidase fusion proteins to the nuclei of transfected 293 cells. Nuclear localization of glypican beta-galactosidase or Fc fusion proteins in transfected 293 cells and C6 glioma cells was greatly reduced or abolished after mutation of the basic amino acids or deletion of the sequence containing the nuclear localization signal, and no nuclear staining was seen in the case of heparan sulfate and chondroitin sulfate proteoglycans that do not possess a nuclear localization signal, such as syndecan-3 or decorin (which is closely related in structure to biglycan). Transfection of COS-1 cells with an epitope-tagged glypican cDNA demonstrated transport of the full-length proteoglycan to the nucleus, and there are also dynamic changes in the pattern of glypican immunoreactivity in the nucleus of C6 cells both during cell division and correlated with different phases of the cell cycle. Our data therefore suggest that in certain cells and central nervous system regions, glypican and biglycan may be involved in the regulation of cell division and survival by directly participating in nuclear processes.

Animals↗
PubMed1997

Transcription of the mouse mu-opioid receptor gene is regulated by two promoters.

Two transcription initiation sites have been identified in the mouse mu-opioid receptor (MOR) gene at approximately -793 and -268 upstream of the translation start site. To test if the MOR gene contains two functional promoters, chimeric constructs of mouse MOR deletion fragments, fused to a luciferase reporter gene, were transiently transfected into the neuroblastoma cell line SK-N-SH, a MOR-expressing cell line, and two MOR-non-expressing cell lines. Results from transient transfection assays confirmed the existence of two functional independent promoters in the mouse MOR gene, and also revealed that the region from -1337 to -93 does not contain all the elements necessary to confer tissue-specific expression of the MOR gene.

Animals↗
PubMed1997

Exclusion of BMP6 as a candidate gene for cleidocranial dysplasia.

Cleidocranial dysplasia (CCD) is an autosomal dominant, generalized skeletal dysplasia in humans that has been mapped to the short arm of chromosome 6. We report linkage of a CCD mutation to 6p21 in a large family and exclude the bone morphogenetic protein 6 gene (BMP6) as a candidate for the disease by cytogenetic localization and genetic recombination. CCD was linked with a maximal two-point LOD score of 7.22 with marker D6S452 at theta = 0. One relative with a recombination between D6S451 and D6S459 and another individual with a recombination between D6S465 and CCD places the mutation within a 7 cM region between D6S451 and D6S465 at 6p21. A phage P1 genomic clone spanning most of the BMP6 gene hybridized to chromosome 6 in band region p23-p24 using FISH analysis, placing this gene cytogenetically more distal than the region of linkage for CCD. We derived a new polymorphic marker from this same P1 clone and found recombinations between the marker and CCD in this family. The results confirm the map position of CCD on 6p21, further refine the CCD genetic interval by identifying a recombination between D6S451 and D6S459, and exclude BMP6 as a candidate gene.

Bone Morphogenetic Protein 6↗