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Biomedical subjects

L Yang

Publications and source records attributed to L Yang.

At least 271 records · Page 15Linked to original sources
PubMed2000

A method for removal of CO from exhaust gas using pulsed corona discharge.

An experimental study of the oxidation of CO in exhaust gas from a motorcycle has been carried out using plasma chemical reactions in a pulsed corona discharge. In the process, some main parameters, such as the initial CO concentration, amplitude and frequency of pulses, residence time, reactor volume, and relative humidity (RH), as well as their effects on CO removal characteristics, were investigated. O3, which is beneficial to reducing CO, was produced during CO removal. When the exhaust gas was at ambient temperature, more than 80% CO removal efficiency was realized at an initial concentration of 288 ppm in a suitable range of the parameters.

Air Pollution↗
PubMed2000

[Wetland ecosystems formation and its protection in Yellow River Delta].

Site investigation, satellite photo analysis and historic material analysis show that the vast neonatal wetlands in Yellow River Delta were created by high concentration sediment of the river and the land-sea evolution. Affected by the regional climate, landform, geological deposition, soil, vegetation and their interactions, the wetlands covered 4.5 x 10(5) hm2, 6.84 x 10(4) hm2 of which were artificial wetlands. The wetland ecosystems changed with the waving of the Yellow River Mouth and the land development in the Delta area. From ocean to land, the sublittoral aquatic wetland, eulittoral wetland, eplittoral salt wetland, bulrush-quitch wetland, meadow wetland and land agroecosystem were developed. The wetland ecosystems had abundant biological resources, including 1524 wild animals, 300 birds and 1040 fishes, which were changed recently by the oil development and affected by the interruption of Yellow River. Wetland protection should be strengthened in resources utilization.

Conservation of Natural Resources↗
PubMed2000

[Evaluation of tumor necrosis factor-alpha and interleukin-6 levels in serum and peritoneal fluid of patients with endometriosis].

OBJECTIVES: To evaluate the levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) before and after conservative laparoscopic surgery in patients with endometriosis. METHODS: The TNF-alpha and IL-6 levels in serum and peritoneal fluid of 20 endometriotic patients and 10 control patients were determined by radioimmunoassay. RESULTS: Significant parallel relationship existed between the stage of endometriosis and the TNF-alpha and IL-6 levels in serum and peritoneal fluid in endometriosis patients (r values: serum: 0.80, 0.52; peritoneal fluid: 0.79, 0.49, P < 0.05). After clearance of endometriosis foci with laparoscopic conservative surgery, the TNF-alpha and IL-6 levels decreased significantly. CONCLUSION: Measuring TNF-alpha and IL-6 level may have important value in postoperative follow-up, surveillance and evaluation of the effectiveness of surgery.

Adult↗
PubMed2000

Clinical significance of changes in beta-adrenoreceptors in peripheral lymphocytes in patients with essential hypertension.

OBJECTIVE: To explore the relationship of beta-adrenoreceptor density and function with the condition of patients with essential hypertension. METHODS: In the present study, 69 male patients with essential hypertension at different stages were compared with a group of age-matched normotensive controls. beta-adrenoreceptor maximum bound volume (Bmax) in peripheral lymphocytes was measured by 3H-dihydroalprenolol (3 H-DHA) radio ligand binding. beta-adrenoreceptor responsiveness was determined by Salbutamol (injection). RESULTS: In patients with essential hypertension at stages I and II, Bmax was significantly higher (P < 0.01 and P < 0.001, respectively) and the chronotropic doses of Salbutamol required to increase the heart rate by 30 beats/min (CD30) were significantly lower (P < 0.01 and P < 0.001, respectively) than in age-matched normotensive control subjects. In patients with essential hypertension at stage III, Bmax was significantly lower and CD30 was significantly higher (both P < 0.01) than those in the age-matched normotensive control subjects. Bmax was significantly higher and CD30 was significantly lower (both P < 0.001) in patients with essential hypertension and with left ventricular hypertrophy (LVH) than that in patients with essential hypertension but without LVH. In patients with essential hypertension and heart failure, Bmax was significantly lower and CD30 was significantly higher (both P < 0.001) than those in patients with essential hypertension without heart failure. CONCLUSIONS: The changes of beta-adrenoreceptor density and function were related to hypertension, hypertension complicated with ventricular hypertrophy, and heart failure. They may be viewed as indexes of the condition in the patients with essential hypertension.

Adrenergic beta-Agonists↗
PubMed2000

[The effects of the complex of rhBMP2 and fibrin sealant on dental pulp].

OBJECTIVE: To investigate the reparative dentine formation induced by the complex of recombinant human bone morphogenetic protein 2 (rhBMP2) and fibrin sealant (FS) in dog tooth. METHODS: Freshly exposed molars, premolars and cuspids were treated with the complex of rhBMP2/FS, rhBMP2 and Ca(OH)(2) paste which served as control. RESULTS: The wound healing of exposed pulp treated with FS seemed to be better than that without FS. Dentine bridge formation was observed in pulp treated with the complex at 7 days, with rhBMP2, Ca(OH)(2) at 28 days. At 63 days after operation, the cases of tubular dentine bridge formation of the pulp treated with the complex were more than that of pulp treated with rhBMP2. CONCLUSION: The synergistic effects of FS and the complex rhBMP2 exist and can be used as bioactive pulp capping agent.

Animals↗
PubMed2000

[Magnetic resonance angiography in assessing changes of pre-and post-disconnective portal system in patients with portal hypertension].

OBJECTIVE: To evaluate the role of magnetic resonance angiography (MRA) in assessing the portal system changes in patients with portal hypertension after pericardial devascularization and splenectomy. METHODS: The portal diameter, blood velocity and flow, collateral circulation, variceal vein and other portal parameters of 15 patients with portal hypertension receiving pericardial devascularization and splenectomy and splenectomy were comparatively evaluated with Siemens 1.5 T MRI 1 week before operation and 2 weeks after operation. RESULTS: The portal diameters decreased after operation, with the disappearance or alleviation of esophageal and fundal variceal veins. In 15 patients, 9 showed. The blood velocity and flow of the portal veins were lower postoperatively. than those preoperatively; In 15 patients, 9 showed increased gastric imaging intensity after operation. CONCLUSIONS: MRA can provide high quality and concrete 3-dimensional information about the portal system and hemodynamics of portal hypertensive patients. It is an important non-invasive way in evaluating the effects of operations and long-term follow-up. Postoperative gastric venous congestion possibly causes increased portal hypertensive gastropathy after disconnection.

Blood Flow Velocity↗
PubMed2000

[Changes of blood circulation of the extremity with tibia shaft defects treated with external fixation].

OBJECTIVE: To study external skeletal fixation for long tubular bony defect by end to end compression with lengthening (EECL) and segmental bone transport by lengthening (STBL). METHODS: About 20% - 30% of the original length was resected from the middle shaft of the tibia in 10 goats of 1 - 2 years of age. The bony defect ends were shortened step by step with the sulcated half-ring external fixator. Changes of the blood flow of the distant extremity were measured with pulse-dopplar monitor, reference blood flow, and angiograph. RESULTS: The blood flow of the distant extremity was not affected when bony defect was less than 15% of the original length. Blood circulation disorder would appear in the distant extremity when bony defect ranged from 15% to 20% of the original length. The distant extremity would necrose because of obstruction of blood circulation when bony defect was more than 20% of the original length. CONCLUSIONS: EECL can be recommended if bony defect is less than 15% of the original length. SBTL might be the only feasible way if bony defect is more than 20% of the original length. If bony defect is within 15% and 20%, EECL should be applied with great care while watching the extremity circulation with pulse-Dopplar monitor.

Animals↗
PubMed2000

[Changes of blood vessels in glucocorticoid-induced avascular necrosis of femoral head in rabbits].

OBJECTIVE: To evaluate the effects of fatty tamponade in medullary cavity (serious intramedullary fatty infiltration) on the changes of blood vessels in femoral heads during the pathological process of glucocorticoid (GC)-induced avascular necrosis (AVM) of the femoral heads. METHODS: The animal model of AVN was established with injection of dexamethasone (DEX) at a high dose of 2.5 mg x kg(-1) x d(-1) in rabbits. Histopathological and morphological changes of blood vessels in the femoral heads were investigated during GC-treatment and after the cessation scanning electron microscope, light microscope, and image analysis. RESULTS: At the 2nd week of DEX-treatment, the fatty tamponade in the medullary cavity appeared in the femoral heads. Intramedullary vascular sinusoids were pressed by an excess of lipocytes and became narrow. The impressions of lipocytes on the surface of vascular sinusoids were definitely displayed on the vascular casts and ink-perfused slides of the femoral heads. These changes were pronounced with the prolongation of the treatment and the vascular sinusoids gradually lost their characteristics. Image analysis showed that the vascular area in the femoral heads continuously decreased. At the 8th week, the effects of fatty tamponade were the most marked. Intramedullary vessels became very sparse and the vascular area decreased to 1/4 of the controls. At the 6th week after the GC-treatment cessation, intramedullary fatty infiltration still existed. The blood vessels were fine and sparse, and the structural features of vascular sinusoids disappeared in the load-bearing regions of the femoral heads. At the 4th week, typical osteonecrosis focuses appeared in the femoral heads. The focuses became larger and the degree of osteonecrosis was increasing with the time of experiment. CONCLUSION: The fatty tamponade in the medullary cavity is one of the important pathological factors causing ischemic damage to the femoral heads, and plays an important role in the early stage of GC-induced AVN.

Animals↗
PubMed2000

[Control genes of chondrocyte apoptosis in osteoarthritic articular cartilage].

OBJECTIVE: To investigate the expression of bax and bcl-2 in normal human articular chondrocytes and in osteoarthritic articular cartilage. METHODS: The samples of articular cartilage were obtained from 9 patients and 6 normal subjects. Bax and bcl-2 mRNA were detected by reverse transcriptase/polymerase chain reaction (RT-PCR) and their expression proteins were analyzed immunohistochemically. TUNEL technique was used to study apoptosis in situ. RESULTS: Bax and bcl-2 mRNA was detectable in chondrocytes of both osteoarthritic and normal cartilage. Bax mRNA of chondrocytes from patients with osteoarthritis (OA) was overexpressed compared with the normal controls (P < 0.01), and OA cartilage chondrocyte also expressed more bcl-2 mRNA than the controls (P < 0.05). There was no statistically significant difference of bax/bcl-2 between the two groups. Immunohistochemical staining demonstrated the same level of bax and bcl-2 proteins as their mRNA. A greater proportion of apoptotic chondrocytes were found in the OA cartilage than that in normal controls (4% - 14% versus 0 - 2%). CONCLUSIONS: Our results suggested that chondrocyte apoptosis was co-regulated by both bax and bcl-2. The ratio of bax to bcl-2 may contribute not only to the lower percentage of apoptotic chondrocytes, but also to the chronic pathologic process in OA.

Adult↗
PubMed2000

[The protective effect of ligustrazine on optic nerve axons in rabbit eyes with continuous elevated IOP].

OBJECTIVE: To investigate the effects of ligustrazine on optic nerve axons in rabbit eyes with continuous elevated intraocular pressure (IOP). METHOD: Thirty-six NZ rabbits with continuous elevated IOP induced by injection of alpha-chymotrypsin into anterior chamber were divided into two groups by randomization: treatment and control group. Ten mg/kg ligustrazine injected into the treatment group every day for 3 weeks began on the 7(th) day after IOP elevated continuously. The changes of conjunctival microcirculation and optic nerve axonal ultrastructure were observed at different time points. RESULTS: The destruction of conjunctival microcirculation and axonal ultrastructure was milder in treatment group than that in the control group. In addition, the total number of axons and the percentage of axons in optic nerve area were higher, whereas the axonal diameter was smaller in the treatment group. CONCLUSION: It is suggested that ligustrazine protect optic nerve axons from more damage induced by elevated IOP through improving ocular microcirculation.

Animals↗
PubMed2000

[Epidemiological and clinical characteristics of Kawasaki disease in Shanxi province].

OBJECTIVE: The objective of this paper is to describe the epidemiological and clinical characteristics of Kawasaki disease (KD) in Shanxi province, China during a 5 year - period from January 1993 to December 1997. METHODS: A province - wide epidemiological survey on Kawasaki disease (KD) was carried ont by the China - Japan Kawasaki disease study group. The questionnaire form and the diagnostic criteria of KD which was prepared by the Japan Kawasaki disease research committee and translated into Chinese were sent of the departments of pediatrics of all the hospitals with 100 or more beds in Shanxi province. All the KD patients who were diagnosed during the observation period from 1993 to 1997 were asked to report to this survey. The database of reported KD in this survey was analyzed at the Department of pediatrics of the Shanxi provincial people's hospital, Xian, China. All the patients that satisfied the diagnostic criteria were included. RESULTS: A total of 105 (70%) hospitals responded and 376 cases of KD were confirmed. More cases were reported in 1993 and 1994. Of the total patients reported, 69% were children under 3 years old with male to female ratio of 1.6:1. The proportion of patients with cardiac sequelae was 19% with male to female ratio: 3:1. There were 4 fatal cases with a fatality rate of 1%. CONCLUSIONS: Since KD is common in China continuous surveillance is necessary to maintain high awareness of KD so as to identify possible risk factors and its association with other disease.

Adolescent↗
PubMed2000

[A 1:2 matched case-control study on the risk factors of uterine myomas].

OBJECTIVE: To investigate the risk factors and their association with Uterine myomas. METHODS: A 1:2 matched case-control study was carried out in Guangzhou including 211 cases and 422 controls. Data were analyzed with conditional logistic regression. RESULTS: Results showed that Pelvic inflammatory, Erosion of Cervix, Menopathy, Adnexitis and family history of Uterine myomas were identified as risk factors, with odds ratios of 3.101, 2.904, 3.942, 7.742 and 2.426 respectively while delayed menstruation was proved to be a preventive factor, with odds ratios of 0.841. CONCLUSION: Uterine myomas seemed to be related to Pelvic inflammatory, Erosion of Cervix, Adnexitis, Menopathy and family history of Uterine myomas.

Adult↗
PubMed2000

[Relationship of bcl-2 gene expression with cell proliferation and apoptosis in human gliomas].

OBJECTIVE: To investigate the relationship of bcl-2 gene expression level in human gliomas with the malignant degree, cell proliferative activity and apoptosis of the tumors. METHODS: The expression of bcl-2 mRNA, bcl-2 protein and proliferating cell antigen, and the apoptosis in sixty-nine human glioma specimens with different malignant grades were studied using in situ hybridization, in situ cell death detection (TUNEL method) and immunohistochemistry. RESULTS: Of the 69 gliomas, 64 (92.8%) and 60 (87.0%) expressed bcl-2 mRNA and bcl-2 protein, respectively. The expression levels of bcl-2 mRNA and bcl-2 protein were correlated positively with each other (r(s) = 0.999, P < 0.01). The expression levels of bcl-2 mRNA and bcl-2 protein were both higher in WHO grade IV gliomas than in grade III gliomas, and the expression was lowest in grade I-II gliomas (P < 0.02 approximately 0.001). With the increase in the expression of bcl-2 protein, the cell proliferating activity increased and apoptosis decreased in the tumor cells. There was significant difference of cell proliferation and apoptosis between + + + group and + + group of bcl-2 protein expression (P < 0.05) as well as between both the former groups, and the negative and + group (P < 0.01) respectively. CONCLUSIONS: Over-expression of bcl-2 gene inhibits apoptosis of glioma cells, and the inhibitory intensity increases with the ascending of bcl-2 gene expression level in glioma cells. Both the decrease in apoptosis caused by bcl-2 gene over-expression and the excessive cell proliferation promoted by other gene abnormalities may result in unlimited cell accumulation, which may play an important role in the development and malignant progression of gliomas.

Adolescent↗
PubMed2000

[Inhibition of the activation and collagen production of cultured rat hepatic stellate cells by antisense oligonucleotides against transforming growth factor-beta 1].

In order to investigate whether the antisense oligonucleotides (ASON) against TGF beta 1 inhibit the activation and collagen production of cultured rat hepatic stellate cells, the authors synthesized two 20-mer phosphorothioate antisense oligonucleotides and their sense or missense oligonucleotides, and then treated the rat hepatic stellate cells (HSC) with these oligonucleotides at different concentrations respectively. HSC activation was assessed by the expression of alpha-smooth muscle actin (alpha-SMA), and TGF beta 1 level was determined by a standard bioassay. The production of collagen was measured by the incorporation of 3H-Proline into cultured rat HSCs. The results showed that the ASON against the translation initiation region of TGF beta 1 at a final concentration of 10 mumol/L could inhibit the HSCs activation, the secretion of TGF beta 1 and the production of collagen in HSCs significantly (P < 0.05), whereas the controls (sense or missense oligonucleotides) had no effect at the same concentration. All of the oligonucleotides had no cytoxicity to HSCs. These findings suggested that TGF beta 1 ASON might be useful for the treatment of hepatic fibrosis.

Actins↗
PubMed2000

[The effect of heparin on mesangial cells proliferation and cytokines production].

The human glomerular mesangial cells(MC) proliferation and cytokines secretion were detected by using MTT method and biological active method so as to assess the effects of heparin on the cultured human glomerular MC induced by lipopolysaccharides (LPS). The results showed that there were basic production of interleukin-6(IL-6) and tumor necrosis factor-alpha (TNF-alpha) on MC in the control group without LPS, that high-concentration heparin(500 U/ml) increased the effects of LPS on MC, and that low-concentration heparin (5 U/ml) conversely inhibited the effects of LPS on MC. These data indicate that the low-concentration heparin could inhibit the proliferation of MC and the secrection of IL-6 and TNF-alpha induced by LPS, and hence provide an experimental evidence for administration of heparin in the treatment glomerular disease.

Cells, Cultured↗
PubMed2000

[Comparison of efficiency and merits of two parameters for bronchial challenge test by use of a simple equation].

The aim of this study was to investigate the relationship, merit and weakness of two parameters--the FEV1 and sGaw--for bronchial challenge test. The 36 cases of asthma patients were subjected to bronchial challenge test with FEV1 and sGaw as the test parameters simultaneously. A simple calculative equation was used. The Mch (challenge medicine) concentrations for a 20% decrease of FEV1(PC20FEV1) and for a 35% decrease of sGaw (PC35 sGaw) were figured out. The results showed that PC20 FEV1 and PC35 sGaw were 2.73 +/- 2.92 g/L and 1.50 +/- 2.03 g/L respectively. A significant difference between them was noted (P < 0.05), and their coefficient of correlation r = 0.738. The linear regression equation was PC35sGaw = 0.100 + 0.513 x PC20 FEV1. PC35sGaw was obviously lower than PC20 FEV1; the Mch amount for PC35sGaw was almost one half of that for PC20 FEV1, which indicated that sGaw was more sensitive than FEV1 as a parameter for bronchial challenge test. The FEV1, however, needs a relatively low standard of instrument, so it is more obtainable and popularized.

Adult↗
PubMed2000

[Re-evaluation of proteinuria and qualitive methods for diagnosis of diabetic nephropathy].

This study was aimed to re-evaluate the proteinuria quantitative and qualitative methods for diagnosis of diabetic nephropathy (DN). 136 cases were divided into two groups of proteinuria negativeness and postiveness by the results of urine routine examination. The clinical and biochemical indices and the frequencies of other diabetic complications of the two groups were compared. The results showed that the blood glucose and glycated Hb in the two groups were increased, especially in the proteinuria negative group (P < 0.01 and 0.05, respectively). There was a high prevalence of hypertension and other diabetic complications in the two groups, and it was higher in the positive group than in the negative group (P < 0.05 and 0.01, respectively). The frequencies of hyperlipoproteinemia in the two groups were over 40%, but no significant defference was observed between them (P > 0.05). There was correlation between hypertension and proteinuria (P < 0.01) but no correlation between diabetic retinopathy and proteinuria. The prevalence of azotemia in the proteinuria negative group was 17.07%. These suggest that the amount of proteinuria can not completely reflect the duration and severity of DN. Negative proteinuria in routine examination cannot rule out DN. For diagnosis of DN, it is necessary to think about all data on blood glucose, blood lipid, blood pressure and the change in fundus oculi.

Adolescent↗