An efficient, practical synthesis of 2-methoxyestradiol

An efficient and practical scheme to synthesize 2-methoxyestradiol has been developed. The key step was the copper-mediated methoxylation using ethyl acetate as a co-catalyst to introduce a methoxyl group. These synthetic procedures of four steps from 17β-estradiol as starting material gave 2-methoxyestradiol with a 61% overall yield.     

孕马血清促性腺激素和氯地酚对猕猴超数排卵效果的观察

用孕马血清促性腺激素,总剂量为1550—2000单位,分4—7天处理猕猴,可促使其每侧卵巢出现滤泡超数发育,随后静脉注射入绒毛膜促性腺激素2500单位,在24小时内,猕猴即可出现超数排卵。     

墨红鲜花香气(头香)成分分析

利用 XAD-4憎水性吸附树脂采集墨红头香,以毛细管气相色谱双柱保留指数和 GC/MS/DS 联用方法鉴定头香的化学成份。共分离鉴定或初步鉴定了45种组份,其中含量较大的有乙酸芳樟酯(14.98%),柠檬烯(12.07%),甲基苯甲醚(9.88%),香茅醇(4.82%),乙酸巳酯(3.98%),β-石竹烯(4.55%),芳樟醇(3.18%),正巳醇(3.17%)等.     

胆碱能神经对人餐后神经降压素释放的影响

本文比较了6名健康成人进食、餐前肌注阿托品以及单纯咀嚼食物后的血浆神经降压素样免疫活性物质(NTLI)水平的变化,以探讨胆碱能神经对神经降压素释放的影响。用放射免疫测定法分别测定NTLI和胰多肽(PP)的含量,以便同时比较两者释放的状态。6人的基础血浆NTLI和PP的水平平均分别为15.7±2.4和16.6±9 7pmol/L。进食后,血浆NTLI和PP水平均显著增高,并呈双相反应。第一个血浆NTLI高峰平均为60.7±13.2pmol/L,出现于餐后的20min。餐后90min,又出现另一个高峰,其平均水平为58.8±8.2pmol/L。在进食前肌注阿托品1mg,餐后的第一个血浆NTLI高峰消失,而第二个高峰仍存在。单纯咀嚼食物后,血浆PP水平明显增高,而对NTLI的释放无刺激作用。本文结果提示,餐后早期的神经降压素释放的调节是由非迷走胆碱能神经参与的,而后期的释放不受胆碱能神经的影响。     

Scavenging effect of extracts of green tea and natural antioxidants on active oxygen radicals

With the use of the spin trapping methods, the scavenging effects of the extracts of green tea and other natural foods are studied. In stimulated polymorphonuclear leukocytes (PMN) system, water extract fraction 6 (F6) from green tea and green tea polyphenols (GTP) have the strongest scavenging effect on the active oxygen radicals, much stronger than vitamin C (Vc) and vitamin E (VE). Rosemary antioxidants (RA) and Curcumin (Cur) have weaker scavenging effects than Vc, but stronger than VE. In Fenton Reaction, Cur has the strongest scavenging effect (69%) on hydroxyl radicals. In irradiation, riboflavin system F6(74%) and GTP(72%) have very strong scavenging effects that are weaker than Vc, but much stronger than VE (23%). With the use of spin probe oxymetry, the oxygen consumption in respiratory burst of stimulated PMN were measured when the antioxidants existed in these systems. The results demonstrated that these antioxidants did not affect the respiratory burst of human polymorphonuclear leukocytes stimulated with PMA.     

促胰液素对血管灌流大鼠离体胃运动的抑制作用

本工作采用血管灌流大鼠离体胃制备,探讨促胰液素对胃运动的影响。结果表明:(1)促胰液素能明显抑制胃窦自发和五肽胃泌素兴奋的胃运动;(2)抗促胰液素血清可完全取消促胰液素的抑制胃窦运动作用;(3)抗生长抑素血清和消炎痛都能阻断促胰液素的抑制胃窦运动作用。上述结果提示,促胰液素的抑制作用除通过直接作用于促胰液素受体外,还可能部分通过胃窦局部生长抑素和前列腺素介导来抑制胃的运动。     

Inhibited enzyme electrodes. Part 3: A sensor for low levels of H2S and HCN

It is shown that an inhibited enzyme electrode, using cytochrome oxidase, will respond to H₂S, HCN and azide ion. For all three inhibitors the kinetics of the inhibition and recovery processes have been analysed using the theoretical model presented previously (Albery et al., 1990a). Rearrangement of the differential equation describing inhibition and the development of the necessary software has enabled us to obtain values of the concentration of inhibitor in a matter of seconds after exposure of the sensor. The sensor will measure concentrations of H₂S down to 1 ppm in the gas phase and concentrations of HCN and azide ion down to 0·4 μmol dm⁻³ in the solution