裂殖酵母生物合成L-苯基乙酰基甲醇的研究

用裂殖酵母作为生物催化剂，催化苯甲醛与丙酮酸合成L苯基乙酰基甲醇（L-PAC），后者为合成L-麻黄素等多种药物的前体，转化反应的最佳温度为28℃，pH6．0，时间16h，苯甲醛用量160-200mmol／L，丙酮酸120～180mmol／L，LPAC产量可达15g／L。     

辛醇/水两相体系中生物合成L-苯基乙酰基甲醇的研究

利用酿酒酵母作为生物催化剂合成L-苯基乙酰基甲醇(L-Phenylacetylcarbiol,L-PAC)的过程中,通过加入有机溶剂(辛醇)形成两相体系,可改善底物和产物的溶解度,以减少对细胞内丙酮酸脱羧酶(PDC)的强烈抑制和钝化作用,从而促进L-PAC产量的提高。实验结果表明,两相体系合成L-PAC的最佳条件为活化60 min,苯甲醛的起始浓度940 mmol/L,丙酮酸钠的起始浓度460 mmol/L,葡萄糖的含量8%,水醇两相体积比为3∶1,且加入一定量的甘油时,L-PAC产量可达在醇相中24.1 g/L和水相中3.7 g/L,比单一水相体系高出1.8倍。     

两相体系中固定化细胞生物合成L-苯基乙酰基甲醇

目的生物合成L-苯基乙酰基甲醇(L-PAC)。方法在10%石油醚/水两相体系中,利用固定化酵母细胞生物合成L-麻黄素的重要中间体L-PAC。结果确定在最佳温度28℃,pH 6.46,活化时间30 min,反应时间10 h,苯甲醛浓度为3 mL/L,添加少量β-环糊精等的条件下,以2%海藻酸钙和10%聚乙烯醇为复合载体,生物合成L-PAC,产量可达8.34 g/L。结论为生物合成L-PAC提供了一种很好的方法。     

响应面法优化微生物萃取转化制备L-苯基乙酰基甲醇的工艺

目的:优化微生物萃取转化制备L-苯基乙酰基甲醇(L-PAC)的条件。方法:以啤酒酵母萃取制备L-PAC。采用高效液相色谱法测定L-PAC浓度。以L-PAC浓度为响应值,通过Box-Behnken响应面法对苯甲醛、曲拉通(Triton)X-100和葡萄糖用量这3个主要因素进行考察,同时进行验证试验。结果:苯甲醛和Triton X-100之间的交互作用最为显著,最优因素组合为苯甲醛1.1%、Triton X-100 0.14 g/m L、葡萄糖0.028 g/m L;验证试验中L-PAC的平均浓度为28.04 mmol/L(RSD=1.35%,n=3),与预测值28.01mmol/L的相对误差为0.11%。结论:利用响应面法对微生物萃取转化制备L-PAC的条件进行了优化,得到了各因素的最优组合,可为大批量转化制备L-PAC提供有利参考。     

在苯甲醛乳液中酶促合成(R)-苯乙酰甲醇

R-苯乙酰甲醇 (1)是麻黄碱和伪麻黄碱合成的手性前体物。在一个简单的苯甲醛及丙酮酸的批转化反应中 ,利用来源于丝状真菌爪哇根霉 (Rhizopus javanicus) NRRL 13 161的部分纯化的丙酮酸脱羧酶 (PDC)作为催化剂 ,经改进反应条件可提高 1的产量。生物转化可用 2～ 2 .5 mol/L 的MOPS(起始 p H6.5 )作为缓冲液。高浓度 MOPS、少量乙醇和 KCl都可使 PDC稳定。在起始物为 40 0 mmol/L的苯甲酸和 60 0 mmol/L丙酮酸中 ,用 PDC (7.4u/mg)在 2 9h内 ,6℃条件下可产生 5 0 .6g/L(3 3 7mmol/L)的 1。 1的产率分别是 97% (以苯甲醛计 )和…     

用固定化德阿昆合假单孢（Pseudomonas dacunhae CPU 210001）生产L—丙氨酸

用卡拉胶固定含有L-天门冬氨酸-β脱羧酶活性的德阿昆合假单孢（P.dacunhae)。该固定化细胞经0.1mol/L天冬氨酸铵，0.1mmol/LPLP和0.2mol/L醋酸缓冲液（pH5.1)的活化液处理24小时，酶尖力可从620IU/g湿细胞提高到13000IU/g湿细胞，最佳酶反应条件研究的结果显示，在pH6.2-7.25范围内和底物浓度为0.4-0.5mmol/L时。固定化细胞表现最高的酶活力。设计了一个能维持反应液pH和底物浓度的循环式反应器，能将天门冬氨酸结晶直接转化成丙氨酸，在144小时的连续转化中，固定化细胞的平均活力为7000IU/g湿细胞。     

妥布霉素生物合成中磷酸盐的调节研究

本文研究了在发酵过程中补加磷酸盐对氨甲酰妥布霉素生物合成的影响并阐明其具体作用机制。结果表明,于发酵过程中加入5.75mmol/L以上的磷酸盐对CTB生物合成发生明显的负调控作用。其原因可能是磷酸盐自身阻遏L-谷氨酰胺:青蟹-肌醇单酮转氨酶的合成,因而影响了从葡萄糖合成2-DOS氨基化作用。     

β—内酰胺抗生素的生物合成

一、概况青霉素G及V、头孢菌素C、头霉素C生物合成的初始阶段都一样,这些化合物的生物合成全过程见图1。Ingolia及Queener(1988)提出了生物合成基因的分类命名、青霉素和头孢菌素相同的生物合成基因,命名为Pcb(青霉素/头孢菌素生物合成),只限于青霉素或头孢菌素的,分别命名为pen及cef。L-α-氨基己二酸、L-半胱氨酸及L-缬氨酸的酶缩合,伴同发生缬氨酸的异构化而成为D型。在半纯化的酶提取液中,曾观察     

基于脱酰基酶转化阿尼芬净前体echinocandin B条件的研究

脱酰基酶可以将echinocandin B(ECB)脱去酰基侧链得到ECB母核,用于化学合成抗真菌药阿尼芬净。本研究考察了以二甲基亚砜(DMSO)助溶剂的转化体系脱酰基酶对ECB转化的各因素,建立了转化工艺(磷酸缓冲浓度：0.02mol/L,pH7.0,KCl浓度：0.68mol/L,DMSO浓度：15%,ECB浓度：450mg/L,加酶量：10%,转化温度：40℃)。为了提高转化效率,探索了新的转化体系即以β-环糊精助溶剂的转化体系,其优势为：当ECB与β-环糊精的浓度比为1:6时,ECB可在体系中完全溶解,底物浓度可以达到2g/L。     

丝状真菌或其抽提物生物转化苯甲醛为右旋苯基乙酰甲醇

右旋苯基乙酰甲醇 [(R) - (PAC) ]是麻黄碱和伪麻黄碱类生产过程中的手性前体 ,为此检测了 14种丝状真菌的抽提物 ,以评价其产生 (R) - PAC的潜在能力。所有被测菌体的无细胞抽提物在 1.2 ml的规模都能将苯甲醛和丙酮酸盐转化为 PAC,这些转化菌株涵盖的分类谱系范围较广 ,包括子囊菌纲、接合菌纲、担子菌纲等微生物。用爪哇根霉和镰刀菌属微生物的抽提物可获得最高的 PAC终浓度 [起始底物浓度为 10 0 mmol/ L 苯甲醛和 15 0 mm ol/ L 丙酮酸盐 ,经 2 0 h可产生 78～ 84mm ol/ L(11.7～ 12 .6 g/ L) PAC]。右旋 PAC为 90 %～ 93%对…     

乳酸左氧氟沙星氯化钠注射液致严重低血糖

1例78岁女性2型糖尿病患者因恶心、呕吐、反酸、腹泻3d,先后静脉滴注注射用奥美拉唑钠20mg和乳酸左氧氟沙星氯化钠注射液0．3g。静脉滴注乳酸左氧氟沙星氯化钠注射液约10min后患者出现大汗、心慌、面色苍白、意识淡漠,即测血糖3．0mmol／L。暂停静脉滴注乳酸左氧氟沙星氯化钠注射液,给予葡萄糖氯化钠注射液500ml静脉滴注,并进食糖块、面包,约5min后症状缓解。恢复静脉滴注乳酸左氧氟沙星氯化钠注射液,约5min后前述症状复现,即刻血糖为1．9mmol／L。立即停用乳酸左氧氟沙星氯化钠注射液,静脉推注50％葡萄糖注射液20m1后继续静脉滴注5％葡萄糖注射液500ml,约10min后患者低血糖症状消失,输液结束后血糖升至9．6mmol／L。     

重度颅脑损伤患者预后的相关因素分析

目的探讨重度颅脑损伤预后的相关因素。方法对80例特重度颅脑损伤的患者的临床资料进行回顾性分析,对影响颅脑损伤患者预后的相关指标进行探讨。结果存活组患者肌钙蛋白为（5．12±1．89）pg／L、肌酸激酶为（355．0±101．3）U／L、肌酸激酶同工酶为（79．5±23．4）U／L,均显著低于死亡组的（12．13±2．12）pg／L、（687．0±139．2）U／L、（180．2±53．5）U／L（t=12．95、8．96、12．45,均P〈0．05）。存活组患者C反应蛋白、血糖、血乳酸水平分别为（52．34±24．35）mg／L、（6．8±1．5）mmol／L、（7．2±1．3）mmol／L,显著低于死亡组的（67．12±23．31）mg／L、（11．4±4．2）mmol／L、（9．5±2．2）mmol／L（t=2．24、4．25、6．82,均P〈0．05）;存活组脑利钠肽水平为（23．4±3．5）μg/L,高于死亡组的（17．1±2．3）μg／L（t=7．21,P〈0．05）。存活组有27例存在钠失衡,死亡组有15例存在钠失衡,两组差异具有统计学意义（x2=13．64,P〈0．05）。结论C反应蛋白、脑利钠肽、血糖、血钠、血乳酸水平及肌钙蛋白、肌酸激酶、肌酸激酶同工酶浓度是影响重度颅脑损伤患者预后的重要因素,其水平越高,预后越差;脑钠肽水平越低,预后越差。     

HPLC法测定乳酸左氧氟沙星氯化钠注射液中的依地酸二钠

摘要：目的 建立乳酸左氧氟沙星氯化钠注射用中依地酸二钠的测定方法。方法 样液中依地酸二钠经氯化铁衍生化后用 HPLC检测。考察了离子对试剂浓度、磷酸盐浓度、水相pH、有机相比例以及衍生化试剂用量等对测定的影响。结果 优化的 色谱条件为：C18色谱柱,流动相：50 mmol/L磷酸二氢钠溶液(含5 mmol/L的四丁基溴化铵 ,用磷酸溶液调节pH值至4.5)-乙腈 (90:10,V/V);流速：1.0 mL/min;检测波长：257 nm。该方法分析时间仅需10 min。结论 本方法前处理简单快速,具有较好 的准确度、灵敏度和精密度,适用于乳酸左氧氟沙星氯化钠注射用中依地酸二钠的质量控制。     

Successful Use of Hydroxocobalamin and Sodium Thiosulfate in Acute Cyanide Poisoning: A Case Report with Follow‐up

Hydroxocobalamin is an effective first‐line antidote used mainly in monotherapy of cyanide poisonings, while the opinions are different on the effects of its combination with sodium thiosulfate. A 58‐year‐old male committed a suicide attempt by ingesting of 1200–1500 mg of potassium cyanide; he was unconscious for 1–1.5 min. after ingestion with the episode of generalized seizures. On admission to the ICU, the patient was acidotic (pH 7.28; HCO₃ 14.0 mmol/L, base excess ?12.7 mmol/L, saturation O₂ 0.999) with high serum lactate (12.5 mmol/L). Hydroxocobalamin was administered 1.5 hr after ingestion in two subsequent intravenous infusions at a total dose of 7.5 g. The infusion was followed by continuous intravenous administration of 1 mL/hr/kg of 10% sodium thiosulfate at a total dose of 12 g. No complications and adverse reactions were registered. Serum lactate decreased to 0.6 mmol/L the same day, and arterial blood gases became normal (pH 7.49; HCO₃ 27.2 mmol/L, base excess 2.2 mmol/L, saturation O₂ 0.994). The follow‐up examination 5 months later revealed no damage of basal ganglia and cerebellum on magnetic resonance imaging. The neurological examination revealed no pathological findings. On the ocular coherence tomography, the retinal nerve fibres layer was normal. In visual evoked potentials, there was a normal evoked complex on the left eye and minor decrease in amplitude on the right eye. Combination of hydroxocobalamin and sodium thiosulfate can have a positive effect on the survival without long‐term neurological and visual sequelae in the cases of massive cyanide poisonings due to the possibility of a potentiation or synergism of hydroxocobalamin effects by sodium thiosulfate. This synergism can be explained by the different time‐points of action of two antidotes: the initial and immediate effect of hydroxocobalamin, followed by the delayed, but more persistent effect of sodium thiosulfate.     

Lactic acidosis in metformin-treated patients. Prognostic value of arterial lactate levels and plasma metformin concentrations.

OBJECTIVE: The antidiabetic drug metformin has been associated in a small number of patients with lactic acidosis, a serious condition with a poor prognosis. However, because of lack of data, the prognostic significance of hyperlactataemia in metformin-treated patients is not known. METHODS: Data were collected from 49 metformin-treated patients with lactic acidosis (arterial lactate level > or = 5 mmol/L and blood pH < or = 7.35) and available plasma metformin concentration data to investigate the association of arterial lactate levels and plasma metformin concentrations with mortality. RESULTS: The overall mortality rate in this patients sample was 45% and the median arterial lactate level was 13.1 mmol/L. Median lactate levels were similar in patients who survived (13 mmol/L) and those who died (14.3 mmol/L), whereas the median plasma metformin concentration was 3 times higher in patients who survived (20.6 mg/L versus 6.3 mg/L). CONCLUSION: In this, the largest series of metformin-treated patients with lactic acidosis yet reported, 55% of patients survived and these patients had a median arterial lactate level of 13.1 mmol/L. Neither arterial lactate levels nor plasma metformin concentrations were of prognostic significance in relation to mortality in this sample of metformin-treated patients with lactic acidosis. Death in these patients appeared instead to be associated with other hypoxic disease or underlying ill health. These observations suggest that accumulation of metformin may not be as significant with respect to high arterial levels of lactate and their effects as has been traditionally thought.     

The effect of serial administration of bicarbonate on plasma total CO2 concentrations in horses

The administration of alkalinising agents including bicarbonate is of concern to racing authorities because resultant alkalosis may enhance performance and interfere with the detection of drugs in post-race urine. A threshold for total carbon dioxide (TCO₂) of 36.0 mmol/L in plasma (with action limit of 37.0 mmol/L) has been set. Serial dosing of sodium bicarbonate has gained popularity in human athletes but has not been studied in horses previously. Sodium bicarbonate (200 g per horse) and 60 g of an electrolyte-vitamin complex was administered in 2-L water via nasogastric intubation to five Standardbred horses for three consecutive days (total dose bicarbonate 0.42 ± 0.02 g/kg). Serial blood samples were taken over Days 1–5, with the final day (5) intended to simulate a ‘clear day’, and TCO₂ was analysed. Following the first bicarbonate administration, plasma TCO₂ peaked at 6 h (34.8 ± 1.3 mmol/L), returning to baseline by 23 h. On Day 2, four out of the five horses showed a peak greater than 36.0 mmol/L (mean 37.0 ± 2.1 mmol/L). With daily repeated dosing, plasma TCO₂ peaked progressively earlier, and by Day 3, the peak occurred at 2 h and concentrations declined more rapidly. On Days 4 and 5, TCO₂ levels remained low (<32.1 mmol/L on Day 4 and between 27.0–31.2 mmol/L on Day 5). These studies demonstrate that serial dosing of a ‘split dose’ of sodium bicarbonate on three consecutive days does not result in the accumulation or carry-over of plasma TCO₂ levels beyond the levels observed following a single dose.     

Determination of icariin and metabolites in rat serum by capillary zone electrophoresis: rat pharmacokinetic studies after administration of icariin

A simple and rapid method for determination of icariin (ICA) and its two metabolites, icaritin (ICT) and desmethylicaritin (DICT), by capillary zone electrophoresis has been developed and validated. Optimum separation of ICA, ICT, and DICT was obtained on 43.6 cm x 50 microm capillary using sodium tetraborate (30 mmol/L), monobasic sodium phosphate (50 mmol/L)-acetonitrile (50:50, v/v) (pH 10.0) as running buffer. Carbamazepine (CMP) was used as internal standard (IS). The temperature and voltage were optimized at 25 degrees C and 12 kV, respectively. The limit of detection of ICA was 1.0 mg/L (S/N = 3) by UV detection at 270 nm. The elaborated method was tested in vivo after administration of a single dose of 120 mg ICA/kg to healthy rats. Calculated parameters confirmed usefulness of the method in rat pharmacokinetic studies on ICA.     

高效液相色谱法测定利塞膦酸钠的含量

目的建立测定利塞膦酸钠含量的高效液相色谱法。方法色谱柱为汉邦C18柱（250mm×4．6mm,5um）,流动相为缓冲液（含5mmol／L磷酸二氢铵、2mmol／L四丁基溴化铵、1．5mmol／L乙二胺四乙酸二钠,用氢氧化钠调节pH至7．2）-甲醇（75：25,v／v）,流速为1mL／min,检测波长262nm。结果辅料及中间体对样品测定不产生干扰,利塞膦酸钠质量浓度在4．2～37．8ug／mL范围内与峰面积有良好的线性关系,平均回收率为100．5％,RSD为1．1％（n=9）。结论该法可以用于利塞膦酸钠的含量测定。