叶酸

Methods:Beside the control group,other three groups were respectively treated with oral folic acid,folic acid retention-enema and ribavirin iv drop.

200例轮状病毒性肠炎患儿随机分为对照组、叶酸口服组、叶酸保留灌肠组及利巴韦林组，在对照组常规治疗的基础上，叶酸口服组给予叶酸5mg。

Methods The levels of serum Hcy, folate acid and VitB12 were measured in 169 patients with cerebral infarction and 110 normal controls. The condition of carotid arteries was checked by color dopper flow image in CI group. The relationship between the level of serum Hcy and folate acid, VitB12 and CAA condition were analysed. The change of serum Hey level was observed after intervention treatment of folate acid and VitB12 for 4 weeks in CI patients with hyperhomocysteinaemia.

测定169例脑梗死患者及110名正常对照者血清Hcy、叶酸、维生素B12水平；应用彩色多谱勒显像仪对脑梗死患者颈动脉进行检测；分析血清Hcy与叶酸、维生素B12水平以及与CAA程度的关系；观察叶酸、维生素B12干预4周后伴有高Hcy血症的脑梗死患者血清Hcy水平的变化。

On the basis of the kinetic equation of substrate reaction in the presence of urea or guanidine hydrochloride, all microscopic kinetic constants for the free enzyme and enzyme-substrate binary and ternary complexes have been determined. The results of the present studies indicate that:①In the presence of urea or guanidine hydrochloride, enzyme-substrate complexes lose their activity less rapidly than the free enzyme. Therefore, both substrates, NADPH and 7, 8-dihydrofolate, protect dihydrofolate reductase against inactivation.②The denaturation of dihydrofolate reductase by urea follows single-phase kinetics, and changes in enzyme activity and tertiary structure proceed simultaneously in the unfolding process, so it may be an"all or none"process.③The GdnHCl-induced unfolding of the dihydrofolate shows a biphasic transition, while the change in the enzyme activity is a single exponential process. The rate constant of inactivation is consistent with that of the fast conformational change. Therefore, the kinetic intermediate of protein unfolding should be a partially folded and inactive form.

我们根据在脲或盐酸胍存在下的底物反应动力学方程求得游离酶和酶底物二元、三元复合物的微观动力学常数，结果表明：①酶-底物二元、三元复合物的失活速度明显慢于游离酶，说明两个底物二氢叶酸和NADPH对酶的失活都具有一定程度的保护作用；②在脲作用下，酶的失活和构象变化均为单指数项过程，而且酶的活力丧失和三级结构变化是同时发生的，说明二氢叶酸还原酶的脲变性可能是一个"全或无"的两态过程；③在盐酸胍作用下，酶的构象变化为两相过程，而失活则是单指数项过程，酶分子构象变化的快相速度常数与失活速度常数基本一致，因此我们认为二氢叶酸还原酶的盐酸胍变性过程中存在一个没有活力、但仍具备一定空间结构的变性中间体。

Abstract］ objective to identify the relationship between serum homocysteine and carotid artery atherosclerosis in patients with cerebral infarction and effects of foliate,methylcobalamin.methods the concentrations of hcy were determined by means of fluorescence polarization immunoassay and carotid arteries was examined with color doppler ultrasound in 165 patients with cerebral infarction.the subjects were divided into 4 groups according to the severity of lesion of carotid artery.the concentrations of hcy were compared in different groups.the patients with hyperhomocysteinemia received foliate and methylcobalamin.results when lesion of carotid artery became severer,serum hcy was higher.the intima medial thicknesses of carotid artery were significantly decreased in patients with hyperhomocysteinemia who received foliate and methylcobalamin for two years.conclusion hyperhomocysteinemia may play an important role in development of carotid artery atherosclerosis.the intervention of foliate and methylcobalamin may reduce carotid artery atherosclerosis.

摘要］ 目的探讨脑梗死患者颈动脉病变与血清同型半胱氨酸水平的关系及叶酸、甲钴胺长期干预对其影响。方法对165例急性脑梗死患者进行血清hcy的测定及颈动脉超声检查，并按动脉硬化的程度分组，比较不同程度颈动脉粥样硬化患者hcy水平，部分高hcy血症患者给予叶酸、甲钴胺干预，随访2年。结果随着颈动脉病变程度的加重，血清hcy浓度呈上升趋势，高hcy血症干预者动脉内中膜厚度明显减小。结论高hcy血症对颈动脉粥样硬化的形成起重要作用，长期给予叶酸、甲钴胺干预可能减轻颈动脉粥样硬化。

Antifolate Alimta derived from pyrrolo[2,3-d]pyrimidine is a multitargeted antitumor agent, it can inhibit at least five major folate-dependent enzymes: thymidylate synthase, dihydrofolate reductase, glycinamide ribonucleo -tide formyltransferase, aminoimidazole ribonucleotide formyl transferase and C-1 tetrahydrofolate synthetase(C1-S).

吡咯并[2，3-d]嘧啶类叶酸拮抗剂Alimta是一种多靶向的抗癌药物，它能抑制至少五种叶酸依赖性酶：胸苷合成酶、二氢叶酸还原酶、叶酰多聚谷氨酸合成酶、甘氨酰胺核糖核苷酸转甲酰酶及C1-四氢叶酸合成酶(C1-S)。。

Adult minimum daily requirement of folic acid is about 50 micrograms per day of folic acid food content of about 200 - 400 micrograms of folic acid, but not all, are being used, such as improper cooking loss volume could reach 50 - 90%, according to the World Health Organization recommends a daily folic acid requirements for: Infant 60 micrograms, 100 micrograms for children, general adult 200 micrograms, 400 micrograms for pregnant women, lactating women 300 microgram .

成人的每日叶酸最小需要量约为50微克，每天吃的食物中叶酸含量约为200–400微克，但不是所有的叶酸都被利用，如烹调不当，损失量可达到50–90％，根据世界卫生组织的建议，每日叶酸需要量为：婴儿60微克，宝宝100微克，一般成人200微克，孕妇400微克，哺乳妇女300微克。

The reaction of 4-bromaophenol and geranic acid in the presecnce of p-TsOH afforded 4-bromophenolα-cyclogeranoate in which cyclization of geranic acid toα-cyclogeranic acid was followed by esterification ofα-cyclogeranic acid with p-bromophenol.

对溴苯酚与香叶酸在p-TsOH催化作用下发生了香叶酸向α-环香叶酸环化、α-环香叶酸环与对溴苯酚的酯化，得到了唯一产物α-环香叶酸对溴苯酯，产率68%。

The role of folate in health maintenance has moved beyond the prevention of macrocytic anemia. Suboptimal folate status is now associated with neural tube defects, cardiovascular disease and certain cancers.

本研究之目的，旨在评估产蛋鸡饲粮强化叶酸后，其蛋中叶酸堆积的增加程度，并比较蛋鸡对不同型态叶酸的吸收与利用，期以了解蛋鸡对叶酸的利用情形，供往后研究的参考。

Pharmacology function】Huang An the AN oxygen Mi Ding be in the Huang An medicine to suppress the germ a very strong kind of the function to synthesize anti-virus medicine, because of it with for germ to synthesize folic acid demand of to ammonia Ji the benzene be sour to have likeness on the structure, exchange with PABA to contend for two hydrogen folic acids to synthesize Mao, bar the germ synthesize two hydrogen folic acids to synthesize Mao, bar the germ synthesize two hydrogen folic acids, end influence nucleic acid protein of synthesize, repress thus germ of growth breed, to variety E-and E+very strongly repress a function.

磺胺间甲氧嘧啶是磺胺类药物中抑菌作用极强的一种合成抗菌药物，因其与细菌合成叶酸时所需要的对氨基苯酸在结构上具有相似性，与PABA兑争二氢叶酸合成酶，阻碍细菌合成二氢叶酸合成酶，阻碍细菌合成二氢叶酸，最终影响核酸蛋白质的合成，从而抑制细菌的生长繁殖，对多种E-及E+有很强的抑制作用。

Material and methods: Human breast cell line HBL-100 and breast carcinoma cell line MCF-7 were cultured in a medium either in the absence or presence of folacin for 30 days.

材料与方法：将人乳腺细胞株HBL-100和人乳腺癌细胞株MCF-7在叶酸缺乏的培养基和正常培养基中的培养30天，用细胞计数、FCM和电镜判断叶酸缺乏对HBL-100和MCF-7细胞生长、周期分布和凋亡状况的影响；用免疫组化和原位杂交等技术，观察叶酸缺乏对HBL-100P53蛋白表达与mRNA表达的影响；用半定量PCR的方法，测定了叶酸缺乏对HBL-100 P53外显子6、7、8甲基化水平的影响。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。