热应激时大鼠肺组织中β—肾上腺素受体的变化与膜磷...

To explore the relationship between the change of beta-adrenoceptor and the metabolism of phospholipids in lung tissue from acute heat stressed rats, the Bmax of beta-adrenoceptors, the activity of phospholipase A2 (PLA2), the content of phosphatidylcholine (PC) and phosphatidylserine (PS), and membrane fluidity in lung tissue of normal and heat stressed rats were investigated. The relevant parameter values mentioned above were 479 +/- 94 fmol/mg protein, 78.5 +/- 8.2 U, 53.5 +/- 1.7 mg/g.wet. w. and 425.1 +/- 68.1 micrograms/g.wet. w. respectively. Whereas in the heat stressed rats with rectal temperature raised to 42 degrees C for 15 min, the Bmax of beta-adrenoceptor was decreased by 43% (P less than 0.01), the activity of PLA2 increased by 83% (P less than 0.01), the contents of PC and PS decreased by 50% and 47% (P less than 0.01) respectively. A lower membrane fluidity in lung tissue for heat stressed rats was also demonstrated. The results suggest that the decreased binding sites of beta-adrenoceptor in lung tissue of rat during hyperthermia may be contributed to the activation of PLA2, which then accelerated the catabolism of phospholipids such as PC and PS in the cell plasma membrane, with a consequent alteration of membrane fluidity.     

The effect of the enantiomers of ibuprofen and flurbiprofen on the beta-oxidation of palmitate in the rat.

The effects of the enantiomers of ibuprofen (0.25 and 0.50 mmol/kg b.w.) and flurbiprofen (0.01, 0.03, and 0.06 mmol/kg b.w.) on the beta-oxidation of palmitate were investigated in the rat. The mean cumulative exhalation of 14CO2 after ip administration of [U-14C]palmitic acid was significantly reduced over 6 h by ibuprofen at the higher dose but not at the lower dose for either enantiomer. There was no difference between the enantiomers, the reduction over 6 h being 31.3 and 33.0% for (R)- and (S)-ibuprofen, respectively. There was also a significant inhibition of beta-oxidation by flurbiprofen at all 3 doses. Again, there was no stereoselectivity evident in this inhibition. Flurbiprofen was much more potent than ibuprofen in eliciting this effect, the 0.01mmol/kg dose giving a similar reduction in beta-oxidation as observed for the 0.50 mmol/kg dose of ibuprofen. The data support the hypothesis that inhibition of the in vivo beta-oxidation of palmitate by ibuprofen and flurbiprofen is primarily via a nonstereoselective noncoenzyme A-dependent mechanism.     

白暨豚正常心电图的初步探讨

1980年以来,我们测定了白鱀豚(Lipotes vexillifer)“淇淇”和“珍珍”的心电图,并与人和其他海豚的心电图作了比较,从而确定了白鱀豚心电图常规导联的联接方法,并比较完整地描述了白鱀豚正常心电图的特征。研究发现,白鱀豚的心电图各波、段和间期的正常范围基本与人的相近,但T波的特征与人不同,人的T波与同导联的主波方向一致,而白鱀豚的T波却正好相反。P—R间期明显比人的延长。本研究将为白鱀豚心血管疾病的诊断提供重要依据。     

水生观赏植物的调查和研究

水生绿化观赏植物是美化园林水景的重要植物材料,作者通过几年的调查研究和引种栽培,提出了28种(其中荷花含18个品种,睡莲含20个品种)水生绿化观赏植物,同时介绍了20种(其中荷花含6个品种)观赏价值较高的水生绿化观赏植物。     

毒黄素对黄嘌呤氧化酶作用的影响

利用从椰毒假单胞菌(Pseudomona cocovenenans)中所分离提取的毒黄素(toxoflavin)对黄嘌呤氧化酶(EC.1、2 3、2)作用的动力学试验表明,毒黄素是此酶的非必需激活剂,而且对以次黄嘌呤为底物的反应的激活作用明显高于以黄嘌呤为底物的反应。此激活作用属于部分混合型。这一结果为探寻毒黄素对人体的致毒机理提供了一条重要线索。     

辐射增敏剂甲硝唑氨酸对坪期V_(79)细胞DNase活力的影响

研究了辐射增敏剂甲硝唑氨酸(CM)对受照前后坪期V_(79)细胞DNase活力的影响。结果表明CM在一定浓度范围内(1—10mmol/L)对DNase的激活作用有浓度依赖关系。细胞经6—12Gyγ线照后DNase活力亦增高,若照射合并CM处理后,则对DNase激活有相加作用。还就DNase活力升高与DNA链断裂间的可能关系进行了讨论。     

Cu~(2+),Cu~(2+)/Vit C对亚油酸过氧化起动机理的ESR研究

本文直接用亚油酸为材料,利用ESR自旋捕集技术和紫外分光技术,分别检测了脂质过氧化反应过程中产生的中间自由基产物L·和共轭二烯结构,对Cu~(2+),Cu~(2+)/Vit C起动脂质过氧化反应的机理进行了研究。结果表明:Vit C自由基,Cu~(2+),Cu~+都不能起动纯的亚油酸的过氧化;Cu~(2+),Cu~+可以使含有部分过氧化成份的亚油酸继续氧化。     

中国奥甲螨属一新种(蜱螨亚纲:甲螨亚目:奥甲螨科)

本文记述了采自吉林省白城草原的奥甲螨科Oppiidae 奥甲螨属Oppia一新种——白城奥甲螨Oppia baichengensis sp.nov.。对新种的形态特征进行了描述.并对新种与属内近似种作了比较鉴别。文内所用量度单位均为微米(μm)。