碳糊电极溶出伏安法测定奋乃静等抗精神病药物

本文报道一种测定吩噻嗪类治疗精神病药物奋乃静、氟奋乃静、氯丙嗪和三氟拉嗪的灵敏电化学分析方法。该类药物在碳糊电极上预富集后,进行溶出伏安测定,溶出电流与浓度在一定范围内具有线性关系。最低检测限可达5ng/ml。用本方法可以不经分离,直接测定药片和人体液中上述药物的含量。作者提出了一种新型挤压式碳糊电极,对上述药物在该电极上的富集机理和测试条件进行了系统研究。认为药物的富集作用是由吸附和萃取引起的,并用计时库仑法定量地估价了这两部分在富集中所起的作用。     

Effects of norepinephrine and other pharmacological agents on prostaglandin E2 release by rabbit and bovine irides

We have investigated: (a) synthesis and release of prostaglandin E2 (PGE2) and the effects of norepinephrine (NE) and other pharmacological agents thereon in rabbit and bovine irides; (b) the role of Ca2+ and the type of adrenergic receptors involved in PGE2 release by rabbit iris; (c) the structural requirement for catecholamine stimulation of PGE2 release by rabbit iris. Irides were incubated in Krebs-Ringer buffer (pH 7.4) in the absence and presence of pharmacological agents at 37 degrees C for 20 min. PGE2 in the medium was quantitated by radioimmunoassay; or by means of radiometric and chromatographic methods when [1-14C]-arachidonic acid was employed as precursor. Analysis of tissue PGE2 at the start of incubation revealed that rabbit and bovine irides contained about 185 and 18 ng/g tissue, respectively. During 15 min of incubation the release of PGE2 from rabbit and bovine irides was approximately 1100 and 14 ng/g tissue, respectively. We found that the rabbit iris and iris microsomes synthesize PGE2, both from endogenous and exogenous arachidonate pools, at a rate several times as high as that of bovine. Release of PGE2 by irides from both species is time-dependent; the stimulatory effects of NE on PGE2 release by irides from rabbit are more pronounced than those of the bovine; and the NE-induced release of PGE2 was abolished by low concentrations of indomethacin (1.5 microM). Synthesis and the effect of NE on PGE2 release by irides from albino and pigmented rabbit eyes are similar. It is concluded that the differences observed in the synthesis of PGE2 and the effect of NE on its release by rabbit and bovine irides are due to species differences. NE stimulation of PGE2 release by rabbit iris is probably mediated through alpha-adrenoceptors and maximal adrenergic stimulation requires the presence of Ca2+. Ca2+-ionophore A23187 significantly increased PGE2 release. These data suggest that the control step in PG synthesis, that is the release of free arachidonate from membrane phospholipids, could be involved in the NE-induced PG synthesis in this tissue. The structural studies revealed that both the catechol nucleus and the ethylamine polar-side chain are required for catecholamine activation of PG release by the rabbit iris. Thus normetanephrine significantly stimulated PGE2 release by the rabbit iris and iris microsomes; 3-methoxy, 4-hydroxy mandelic acid had no effect; and catechol at 50 microM inhibited PGE2 release by more than 50%. Catecholamines and adrenergic drugs are routinely employed therapeutically to lower intraocular pressure in the eye, and a catecholamine-induced increase in PG synthesis may play a significant role in mediating the pharmacological effects of these therapeutic agents.     

Work in progress: radioprotection of human breast cancer cells by elevation of intracellular cyclic AMP

MCF-7 human breast cancer cells that were treated for one hour prior to X irradiation with the cyclic AMP-inducing agent 1-methyl-3-isobutylxanthine displayed a slight but significant increase in surviving fraction over untreated controls at each radiation dose level. This was accompanied by a two-fold increase in the level of intracellular cyclic AMP.     

Biplane arteriography in ischemia of the lower extremity

A technique for simultaneous bilateral biplane arteriography of the abdomen, pelvis, and lower extremities is described. The biplane views provided clinically significant information in approximately 40% of cases.