Study on the activation of blood platelets by propylene-acidamide grafted polypropylene membrane in vitro

AIM: To evaluate the blood compatibility of a new bioartificial reactor membranous material (propylene-acidamide grafted polypropylene membrane, PP-g-AAm) in vitro. METHODS: Contacted PP-g-AAm membrane and PP (polypropylene) membrane with platelet-rich plasma in a swing bed, 37 ℃, to simulate the conditions in vivo, and another group of PRP without any membranes was set as control group. ELISA was used to study the expression of β-thromboglobulin, and flow cytometry was used to study CD62P and CD63 expression of the activated blood platelets after contacting the two kinds of membranes with PRP. Scanning electrical microscopy was used to study the configuration and numbers of platelet cells adhered on the membranes. RESULTS: After contacting with PRP 30 min, β-TG expression showed marked difference between the two kinds of material groups and the control group (P<0.01, P<0.05), and the difference between the two kinds of membrane groups was also significant (P<0.05). There were obviously differences on the expression of CD62P and CD63 between the two kinds of membranes after contacting with PRP for 30 min (P<0.05，P<0.01). When enlarged 10 000 times, the disfiguration of the platelet cells adhered on the two kinds of membranes after one hour were found by scanning electrical microscopy, and the numbers of platelets on the PP membrane were more than the PP-g-AAm membrane markedly. CONCLUSION: The PP-g-AAm membrane has better blood compatibility than the PP membrane.     

Immunosupressive mechanism of cornus officinalis glycosides on the corneal allograft rejection in rats

AIM: To investigate the influence of the cornus officinalis glycosides (COG) on immunological function of corneal transplantation model of rats, and to clarify the immunosuppressive mechanism of COG through observing the activation of lymphocytes in blood. METHODS: Wister rats were used as recipients and SD rats were used as corneal graft donors, then the corneal allografts transplantation model on the closed colony rats were set up. Splenocytes proliferation and mixed lymphocyte reaction of Wister rats activated by ConA were observed. The phenotype change of CD4, CD8, CD25 in blood in different time postoperatively were observed by the di-sign flow cytometry, and the rate of CD4/CD8 was calculated. RESULTS: 1. The COG suppressed the proliferation of T lymphocytes and one-way mixed lymphocyte reaction on the corneal allografting. 2. The phenotype change of lymphocytes in boold was as follows: there was no significant difference between the different time of the CD4, CD8 expression and the CD4/CD8 rate in blood of the control group. The CD4 positive cells expressed CD25 postoperatively increased obviously. The CD4/CD8 rate of medicine group had the tendency to decrease. The CD4 positive cells expressed CD25 postoperation in the medicine group were less than that in the control group obviously. CONCLUSION: The suppression of the T lymphocyte proliferation, mixed lymphocyte reaction, CD molecule expressed by the activated T lymphocytes and the IL-2 receptor expression may be the main immunosuppressive mechanisms of Cornus officinalis glycosides on the cell-mediated immunity.     

Effect of oxymatrine on mouse allergic contact dermatitis induced by DNFB and lymphocyte proliferation stimulated by Con A

AIM: To explore the inhibitory effect of oxymatrine （OMT） on the allergic contact dermatitis （ACD） stimulated by dinitrofluorobenzene （DNFB） and its effects on the proliferation of the lymphocytes. METHODS: ① An ACD mouse model was established by stimulation with DNFB, and then the mice were injected intraperitoneally with different dosages of OMT， PBS and hydrocortisone （HCT） respectively, the swelling degree of their auricles was examined. ② Carboxyfluorescein diacetate, succinimidyl ester (CFDA-SE) dye and flow cytometer were used to examine the fluorescence intensity changes of lymphocytes stimulated by polyclonal stimulator ConA and OMT. RESULTS: ① compared with PBS group, OMT possessed the strong inhibitory effect on the ACD caused by DNFB in a dose-dependent manner, and its inhibitory effect was equivalent to the HCT of the same dosage with fewer side effects. ② In vitro experiments proved that OMT (500, 125 and 31 mg/L) had the ability to restrain the proliferation of lymphocytes of mouse. CONCLUSION: OMT possesses an inhibitory effect on the ACD induced by DNFB, and OMT is a kind of immunosuppressor.     

Influence of predator stress on levels of IL-1β, IL-6 in BALB/C mice with brain asymmetry

AIM: To investigate the influence of predator stress on hypothalamic-pituitary-adrenal (HPA) axis and IL-1β, IL-6 in mice with brain asymmetry. METHODS: By using paw preference test, right-pawed, left-pawed, and ambidextrous-pawed mice model were established. Mice with brain lateralization were exposed to their predator (cat). After acute and chronic predator stress by cats, EIA and ELISA were applied to detect plasma levels of corticosterone (CS), IL-1β and IL-6. RESULTS: (1) The level of plasma CS: in both acute and chronic predator stress group, right-pawed and ambidextrous mice had a higher level than that in their corresponding normal group (P<0.05). Meanwhile, the two groups also showed higher level than left-pawed in acute stress. Compared with the corresponding group under acute stress, left-pawed had much higher level of CS under chronic stress (P<0.05). (2) The level of plasma IL-1β: in normal group, left and right-pawed mice were higher than that in ambidextrous mice (P<0.01), of which left-pawed was the highest. In chronic stress group, the left-pawed exhibited higher level than that in right-pawed mice (P<0.05). (3) The level of IL-6: after chronic predator stress, ambidextrous mice had much higher level than that in other two groups (P<0.05). CONCLUSION: Under predator stress, the HPA axis and plasma proinflammatory cytokines (IL-1β, IL-6) in BALB/C mice were modulated by the brain asymmetrically, and brain lateralization may influence the function of immuno-endocrine network in psychological circumstances.     

Effect of polyamines on intracellular calcium of the rat cardiomyocytes with anoxia and reoxygenation

AIM: To study the effect of extrogenous low concentration polyamine on cardiomyocyte calcium overload caused by anoxia and reoxygenation. METHODS: Enzymatically isolated rat ventricular myocytes were perfused with normal Tyrode solution for 8 min, then change to anoxia solution for 32 min, at last back to normal Tyrode solution perfusion for 8 min to establish the cardiomyocyte model of anoxia and reoxygenation. Spermine was added extracellularly to the bath before anoxia and spermine, spermidine or putrescine was added extracellularly after reoxygenation. Intracellular calcium fluorescence intensity (FI) was measured continuously by laser scan confocal microscope (LSCM). RESULTS: In the unstimulated state, exogenous spermine (1 mol/L) did not change resting ［Ca2+］i in the rat cardiomyocytes. Adding spermine before anoxia antagonized the ［Ca2+］i elevating caused by anoxia/reoxygenation. Adding spermine after reoxygenation also lowed the enhanced ［Ca2+］i caused by reoxygenation. Considering the potency of two conditions, the former was more efficacious than the later. Spermidine and putrescine also lowed the enhanced ［Ca2+］i caused by reoxygenation, but they were less efficacious than spermine. CONCLUSIONS: The results indicate that spermine given before anoxia or after reoxygenation, antagonized or lowed the cardiomyocytes calcium overload caused by anoxia/reoxygenation, but the later was weaker than the former. The order of potency of the polyamine lighten cardiomyocytes calcium overload caused by anoxia/reoxygenation was spermine>spermindine>putrescine.     

Role of lipopolysaccharide in the development of hepatopulmonary syndrome

AIM: The goal of the present study was to evaluate the possibility about enterogenous endotoxemia in pathogenesis of hepatopulmonary syndrome. METHODS: The rat model of cirrhosis was prepared with compound factors. A small dose of lipopolysaccharide (LPS) was administered intraperitoneally once to aggravate endotoxemia of animal with cirrhosis. The normal rats injected with LPS or injected with LPS combined with glycine (LPS antagonist) were designed as controls. RESULTS: Hepatopulmonary syndrome of rats with cirrhosis had occurred in the end of eighth weeks. Pulmonary pathological changes of cirrhosis rats were exacerbated after administration of a given dose of LPS. Glycine sharply antagonized the biological effect of LPS in vivo and in vitro, inhibited the production of TNF-α by LPS and alleviated various pathological changes of hepatopulmonary syndrome. CONCLUSIONS: Enterogenous endotoxemia in cirrhosis rats might be an important mechanism in the development of hepatopulmonary syndrome. Endotoxin and its mediating effect by way of cytokines (TNF-α) may play a role in the pathogenesis of hepatopulmonary syndrome.     

Hypoxia upregulates CD73 expression in mouse microvascular endothelial cells

AIM: To study the effect of hypoxia on CD73 expression in mouse microvascular endothelial cell line bEnd.3. METHODS: ① bEnd.3 cells were exposed to different periods of hypoxia. ② Concentration of LDH released by bEnd.3 cells into the culture medium was detected. ③ Surface CD73 activity in bEnd.3 cells was measured by HPLC according to the conversion of E-AMP to E-ADO. ④ CD73 mRNA expression were analyzed by semiquantitative RT-PCR. ⑤ Cell surface proteins were biotinylated and CD73 was detected by avidin blots of immunoprecipitation with mAb TY23. RESULTS: ① bEnd.3 cells exposed to hypoxia for 24 h demonstrated a significant increase in LDH release (P<0.01). ②Hypoxia induced CD73 activity in bEnd.3 cells in a time-dependent manner. ③ CD73 mRNA expression increased markedly in hypoxia for 4 h and 8 h (P<0.05). ④ bEnd.3 cells exposured to hypoxia induced a time-dependent increase in expression of CD73 (P<0.05). CONCLUSION: Hypoxia induces CD73 mRNA, protein expression and increases CD73 activity in mouse microvascular endothelial cells.     

气候变化对陇东塬区冬小麦生长发育及产量的影响

分析西峰农业气象试验站冬小麦生育期的观测资料表明,气候变暖使陇东塬区冬小麦全生育期天数缩短,主要是越冬期天数缩短,而冬小麦实际生长的天数并未缩短;气候变暖使冬小麦播种期推迟,成熟期提前,从而使麦田的休闲期延长,延长了复种作物的生长期,为提高气候资源的利用率和单位面积的产量提供了保证。气候变化对冬小麦气候产量的影响具有明显的周期性。     

新疆草地生态安全问题、现状与对策分析

简要介绍新疆草地生态问题的由来及现状，运用新的生态安全理论分析新疆草地生态安全时空特征，指出新疆草地生态安全问题是长期人地矛盾不断尖锐与发展演变而来。人口膨胀引起的资源环境破坏、超载过牧造成对资源的掠夺经营等，使草地稳定自协调机制破坏，草地自然生态系统由稳定走向严重危机，并引发新的牧业危机。分析指出，实现人地关系的和谐，需综合考虑生态、经济、社会历史等方面的因素。其中，绿洲区牧民定居点的综合发展水平是维护草地生态安全、实现牧业可持续发展的关键。实现生态安全与可持续发展的主要对策有：依法监理草地放牧状况、合理利用、改良与保护天然草地、高效经营人工草料基地、提高畜牧业经营水平等。依托的关键技术有：草地资源监测技术、退化草地治理及草地利用实用技术等。