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Biomedical subjects

L Zhao

Publications and source records attributed to L Zhao.

At least 271 records · Page 15Linked to original sources
PubMed1998

A kinetics study on the production of alkaline proteinase by Bacillus licheniformis 2709.

With automatic control fermentation equipment, the kinetics of growth and metabolism of Bacillus licheniformis 2709 was studied with batch culture as well as with fed-batch-culture by controlling the concentration of the growth-limiting substrate. The Monod formula proved to be reasonable in describing the relationship between cell growth rate of B. licheniformis 2709 and the concentration of the growth-limiting substrate in the broth, and the data of product synthesis rate showed that the fermentation type belongs to one partially related to growth.

Bacillus↗
PubMed1998

[Antenatal treatment of maternal-fetal Rh incompatibility hemolysis disease].

OBJECTIVE: To study the effective antenatal treatment of maternal-fetal Rh incompatibility hemolysis disease to improve fetal outcome. METHODS: Besides therapy of plasmapheresis, the immune globulin intravenous infusion (IVIg) was added for antenatal treatment of fetal hemolysis disease due to Rh incompatibility. Every 7-20 days 10 g IVIg was administered according to the titer of Rh antibody in maternal serum. RESULTS: 5 Rh negative pregnant women with poor obsterical history were treated with this protocol. Total IVIg infusion was 12 times with an average of 2.4 times per case, and there was no side effects. Plasmapheresis was used 18 times totally with an average of 3.6 per case. There was no fetal death. All the five newborns underwent exchange transfusion and IVIg therapy, and all were survival. CONCLUSIONS: IVIg may enter fetal blood circulation via placenta, and adjust fetal immune ability to reduce the degree of fetal hemolysis.

Adult↗
PubMed1998

[The effects of nitric oxide synthase on secondary spinal cord injury: an experimental research].

OBJECTIVES: To investigate the effects of the changing amount of nitric oxide on secondary spinal cord injury and determine the role of nitric oxide during secondary spinal cord injury. METHODS: After close spinal cord modest injury (T9) by fluid-percussion model, rats were given saline, small dose of L-NAME (8 mg/kg) and large dose of L-NAME (40 mg/kg) respectively. The changes of hemodynamics, tissue constitution, and neural function were observed. RESULTS: We found small dose of L-NAME had little effects on the hemodynamics but could improve neural function. Whereas, large dose of L-NAME raised the MABP significantly, constricted pial arteriole (90 minutes, 10%), decreased regional spinal cord blood flow (SCBF) (90 minutes, 22%), augmented the dysfunction of neural system. Rats lost weight and the rate of death raised. CONCLUSIONS: These findings indicated that nitric oxide could have dual role during secondary spinal cord injury. Controlling local nitric oxide production suitably through changing the activity of nitric oxide synthase could improve tissue survival and benefit the recovery of neural function.

Animals↗
PubMed1998

[Effect of calcitonin gone-related peptide on coronary thrombosis and thrombolytic therapy].

OBJECTIVE: To inverstigate the effect of Caleitonin gene-related peptide (CGRP) on intracoronary thrombosis, thrombolysis, and reocclusion. METHODS: Thirty-six dogs were divided into three groups: saline solution (NS) group, nitroglycerin(NTG) group and CGRP group. The canine model of intracoronary thrombsis was established. Urokinase(UK) was administered intravenously. The time and rate of intracoronary thrombosis, patency and reocclusion were observed. RESULTS: The time of thrombus formation was markedly prolonged in the CGRP group. (NS 41 +/- 9 min, CGRP 72 +/- 11 min P < 0.01). The time of patency was shorted from 80 +/- 7 min(NS), 70 +/- 11 min(NTG) to 50 +/- 9 min(CGRP) (P < 0.01). The time of reocclusion was increased from 20 +/- 10 min(NS), 39 +/- 7 min(NTG) to 65 +/- 12 min(CGRP)(P < 0.01). CONCLUSIONS: CGRP can delay the intracoronary thrombus formation, assist thrombolysis and decrease the reocclusis after thrombolysis.

Animals↗
PubMed1998

[Spironolactone ameliorates rat pulmonary fibrosis induced by bleomycin A5].

OBJECTIVE: The purpose of this study was to investigate the role of aldosterone in pulmonary fibrosis and the protective effect of anti-aldosterone treatment. METHOD: Rats were divided into control, fibrosis and treatment groups; rat pulmonary fibrosis was induced by endotracheal injection of bleomycin A5 and spironolactone was given 100 mg/kg daily in drinking water to treatment group. 28 days later, plasma, bronchoalveolar lavage fluid(BALF) and tissue aldosterone concentration, as well as lung collagen levels, were determined. RESULT: Plasma aldosterone was higher in fibrosis group than that in control group(469 +/- 161 pg/ml and 319 +/- 115 pg/ml, respectively), but without significant difference (P > 0.05); spironolactone could ameliorate the extent of pulmonary fibrosis, the level of lung collagen was 25% less than that of fibrosis group (3.4 +/- 0.5 mg/g lung and 4.6 +/- 1.2 mg/g lung, respectively; q = 3.7893, P < 0.05), and the level of lung protein was 22% less (50 +/- 4 mg/g lung and 65 +/- 6 mg/g lung, respectively; P < 0.01). CONCLUSION: Spironolactone had some protective effects on pulmonary fibrosis, and aldosterone might play a role in the development of pulmonary fibrosis.

Aldosterone↗
PubMed1998

[Effect of hypoxia on proliferation and alpha 1 (I) procollagen gene expression by human fetal lung fibroblasts].

OBJECTIVE: The effect of 2% hypoxia on the proliferation and alpha 1(I) procollagen gene expression by human fetal lung fibroblast was studied. METHODS: Cell proliferation was determined by cell counting and nonradioactive cell proliferation assay method. alpha 1(I) procollagen gene expression was detected by Northern blot hybridization analysis. RESULTS: Cell number and 490 nm OD expressing low oxygen values were markedly increased by the 24, 48 and 72 h exposure to 2% hypoxia respectively. An obvious increase of the alpha 1(I) procollagen mRNA expression was detected after 24 h exposure to 2% hypoxia. The increase of gene expression could be inhibited by Ligustrazin (30 micrograms/ml, 10 micrograms/ml). CONCLUSIONS: 2% hypoxia plays an important role in the outcome of wound healing and pulmonary vascular remodeling by affecting the function of human fetal lung fibroblasts.

Cell Division↗
PubMed1998

[Clinical study on the forced oscillatory pulmonary function test].

OBJECTIVE: To discuss the change of airway resistance and phase angle (phi) in normal subjects, patients with COPD, asthma and pulmonary fibrosis when the new technique of the forced oscillatory pulmonary function test was applied to measure them as well as the change of pulmonary function of patients with asthma after using bronchodilator. METHOD: Use Custo-vitm forced oscillation device manufactured in Germany to determine airway resistance and phase angle and to compare their statistical differences between normal subjects and patients with pulmonary disease, and then comparing the improvement rates of their FEV1, F-V curve and airway resistance in patients with asthma after inhaling bricasol. RESULT: The measurements of group COPD and asthma were significantly higher than those of normal group (P < 0.05), and there were obvious frequency dependence in these two groups. The results of phase angle in each group of patients were significantly lower than those of normal group (P < 0.05), and the group of patients with pulmonary fibrosis only demonstrates a decrease in phase angle, and the improvement rate of airway resistance in patients with asthma after inhaling bricasol was significantly higher than FEV1 and F-V curve (P < 0.05). CONCLUSION: Forced oscillation is a convenient, quick, and noninvasive new method when applied to measure airway resistance and phase angle. It is especially suitable for patients with severe COPD and better than conventional pulmonary function test in observing therapeutic effect in asthma.

Adult↗
PubMed1998

Temporal and spatial features of slow positive potential related to visual selective response during head-down-tilt.

The temporal and spatial features of visual ERP changes during 2 hour HDT (-10 degrees) were compared with that during HUT (+20 degrees) in 15 normal subjects. The stimuli consisted of two color LED flashes appeared randomly in left (LVF) or right (RVF) visual field with the same probability. The subjects were asked to make switch response to target signals (T) differentially: switching to left for T in LVF and to right for T in RVF, and making no response to non-target signals (N). Five sets of tests were made during HUT and HDT. ERPs were obtained from 9 locations on the scalp. Mean amplitude of the ERPs in the period 0.30-0.55 s were taken as the amplitude of slow positive potential (P400). The results obtained were: (1) The mean amplitude of P400 decreased during HDT which was more significant at the 2nd, 3rd and 5th set of tests; (2) spatially, the reduction of mean P400 amplitude during HDT was more significant for signals from RVF and were more significant at posterior and central brain regions than those from frontal locations. These data provide further evidence showing that the higher brain function was affected by the simulated weightlessness and that this effect was not only transient but also with interesting spatial characteristics.

Adult↗
PubMed1998

[Changes of brain potentials related to selective mental arithmetic during simulated weightlessness].

To study the effect of simulated weightlessness on brain function state, the brain event-related potentials (ERPs) during a selective mental arithmetic task were compared between head down tilt (HDT) and head up tilt (HUT) in 15 normal subjects. The results were: target (T) flash signals induced significant slow positive potentials and they decreased significantly in amplitude especially during HDT as compared with that during HUT. The data provide new evidence indicating that the ability of brain response declined during simulated weightlessness.

Adult↗
PubMed1998

[Management of severe Budd-Chiari syndrome by spleen-internal jugular venous shunt].

OBJECTIVE: To study the operative method for severe Budd-Chiari syndrome. METHOD: 17 patients with severe Budd-Chiari syndrome were treated with splenectomy and spleen-internal jugular venous shunt. RESULT: Follow up for 3 to 20 months 11 patients showed excellent results, 5 good results and 1 died. CONCLUSION: Spleen-internal jugular shunt is effective for the patients with severe Budd-Chiari syndrome.

Adult↗
PubMed1998

[Treating portal hypertension by subtotal splenectomy with retroperitoneal splenic transposition and devascularization: clinical study].

OBJECTIVE: To devise a new surgical procedure for improving the operative effect of portal hypertension caused by hepatic cirrhosis. METHOD: In treatment group, subtotal splenectomy with retroperitoneal transposition was performed in 36 patients of cirrhotic hypertensives. In control group, 36 patients were treated by devascularization. The follow-up period ranged from 3 months to 5.5 years (average 26 months). RESULT: In the treatment group, the rates of disappearance, improvement and absence of changes of esophageal varices were 11.5%, 61.5% and 26.9%, respectively, and in the control group those of improvement were 50.0%, absence of change 45.8% and aggravation 4.2%. There was a significant difference between them (P < 0.05). In the treatment group, hypersplenism disappeared in all. There was also significant difference between the two groups in immunological indexes (P < 0.05). DSA showed abundant collateral circulation in the residual spleen and retroperitoneal wall, which enabled the portal blood flow diverting to retroperitoneal tissues. CONCLUSION: This method possesses the advantages of devascularization and decompression shunt. It is of value in retaining part of spleen in surgical treatment of portal hypertension.

Female↗
PubMed1998

[An immunohistochemical study of basic fibroblast growth factor in early acute myocardial ischemia].

With the use of immunohistochemistry, the expression of basic fibroblast growth factor (bFGF) in early acute myocardial ischemia of rats was studied. It was observed that there was an initial (30 min) rise in bFGF expression in limited ischemic myocardium areas and perimyocardial ischemia areas. The grade of expression of bFGF increased with the continuation of ischemia. The results of image analysis and statistical process suggested that the expression of bFGF reach a high level in ischemic myocardial areas after three hour's of ischemia, significantly higher than in control group and in group B1, but no significant difference in pericardial ischemia areas and normal areas of the same group. In summary, early acute myocardial ischemia is accompanied by rapid and prolonged increase in expression of bFGF with characteristic spatial and temporal kinetic. This finding suggests that the immunohistochemical staining of bFGF provide objective morphologic evidence for the diagnosis of early myocardial ischemia.

Animals↗
PubMed1998

[Immunohistochemical research on brain stem injury: expression of heat shock protein 70 in rat brain after traumatic brain stem injury].

The aim of this study was to determine the expression of heat shock protein 70 (HSP70) as molecular chaperones, following traumatic brain stem injury(TBSI). The expression of HSP70 was detected in respective brain regions of rats 1 h, 3 h, 6 h, 12 h, 24 h after brain stem stabbing wound. Numerous HSP70 immunoreactivity positive blood vessel endothelioid and glia cells were found in cerebral, cerebellar cortex and hippocampus after 1 h, with H.E stain unchanged. In the area near the focal of brain stem injury, HSP70 immunoreactivity positive neurons increased significantly after 1 h of injury, reaching the highest level after 3 h, much higher than in other areas. HSP70 immunoreactivity positive cells still existed after 24 h of injury. It was suggested that TBSI cause the defectiveness of protein structure in brain, and induce HSP70 proteolysis of denature protein including misfolding or aggregate. TBSI can be diagnosed regionally by the increasing of HSP70 immunoreactivity positive neurons in the focal of brain stems.

Animals↗
PubMed1998

[Sensitivity of cationic polymer Eudragit RL to electrolytes and its effect on drug release from Eudragit RL matrix].

The swelling behavior of acrylic polymer Eudragit RL in different concentration and species of electrolyte aqueous media, and the effect of media and polymer swelling on drug release from Eudragit RL matrix system were investigated with nifedipine, chlorpheniramine maleate and indomethacin as model drugs. It was found that Eudragit RL was sensitive to the electrolytes in aqueous media. The swelling of Eudragit RL decreased with increasing electrolyte concentration and was significantly affected by the electrolyte species. The swelling behavior was reversible. The release of 3 drugs from Eudragit RL matrix was remarkably affected by the electrolytes in the media. The rates of release of nifedipine and chlorpheniramine maleate from the polymer matrices were controlled by the polymer swelling behavior, and the rate of release correlated well with the swelling behavior. However, the rates of release of indomethacin from the Eudragit RL matrix were controlled not only by the polymer swelling but also by the drug displacement by the medium anion, which was attributed to the presence of an interaction between indomethacin and Eudragit RL.

Chlorpheniramine↗
PubMed1998

[Quantitative study of catecholamines in normal human dental pulp].

The purpose of this report was to study quantitatively the levels of catecholamines in human dental pulp by high-performance liquid chromatography (HPLC). 10 healthy teeth were selected from the extractions due to orthodontic reasons. The pulp of the teeth were obtained immediately after the extraction and samples were analyzed by means of HPLC for levels of dopamine, epinephrine and norepinephrine. The result showed that the concentration of norepinephrine in human dental pulp was 23.47 +/- 0.52 micrograms/g pulp tissue and dopamine was 19.17 +/- 1.03 micrograms/g pulp tissue.

Catecholamines↗
PubMed1998

Oxidized low-density lipoprotein inhibits acetylcholine-induced vasorelaxation and increases 5-HT-induced vasoconstriction in isolated human saphenous vein.

The present study determined the vasomotor effects of oxidized low-density lipoprotein (ox-LDL) in human saphenous veins and determined whether decreased availability of L-arginine was responsible for the impaired endothelial function. Human saphenous veins were obtained from white males undergoing coronary bypass surgery. We examined the effects of ox-LDL on ACh-induced endothelium-dependent relaxation, sodium nitroprusside-induced endothelium-independent relaxation and 5-HT-induced contraction. ACh-induced vasorelaxation in the presence of L-arginine and ox-LDL was also examined. In addition, we assessed the endothelial influence on the contractile response to 5-HT. ox-LDL significantly inhibited ACh-induced relaxation but did not affect sodium nitroprusside-induced relaxation. L-Arginine pretreatment did not prevent ox-LDL-induced impairment of the relaxation response to ACh. ox-LDL significantly potentiated 5-HT-induced contraction at concentrations between 3 x 10(-6) M and 10(-4) M, an effect that was endothelium-dependent. Denudation of endothelium also significantly enhanced the contractile response to 5-HT. These data suggest that ox-LDL impairs ACh-induced endothelium-dependent relaxation and enhances 5-HT-induced endothelium-dependent contraction in human saphenous vein. L-Arginine deficiency is not responsible for the endothelial dysfunction induced by ox-LDL in human saphenous vein.

Acetylcholine↗
PubMed1998

Identification and characterization of two thrombin-activatable fibrinolysis inhibitor isoforms.

Thrombin-activatable fibrinolysis inhibitor (TAFI) is synthesized by the liver and is thought to circulate in plasma as a plasminogen-bound zymogen. When it is activated by the thrombin/thrombomodulin complex, activated TAFI exhibits carboxypeptidase B-like activity. To study the structure-function relationship of TAFI, we expressed recombinant human TAFI in insect cells. During the cloning of TAFI cDNA from several human liver cDNA libraries, we identified a second TAFI cDNA which differed from the published sequence at 2 positions. One of these sequences resulted in a substitution of alanine for threonine at residue 147, the other was a silent mutation. These substitutions were found in several cDNA libraries from different sources. Using Southern blot analysis, we confirmed the existence of this TAFI polymorphism in the population. In order to compare the activation and activity of TAFI isoforms, we expressed both isoforms in the baculovirus expression system, and compared the enzyme kinetics of the purified proteins. The molecular weight of recombinant TAFI is lower than plasma TAFI due to differences in glycosylation. The two recombinant TAFI isoforms had similar activation kinetics and the activated enzymes had similar carboxypeptidase B-like activity towards small molecule substrates. Their ability to retard clot lysis was found to be similar in a plate clot lysis assay.

Animals↗