Activation-inactivation coupling in Myxicola giant axons injected with tetraethylammonium

Myxicola giant axons internally injected with tetraethylammonium chloride to block potassium currents were examined under voltage clamp. The sodium inactivation time constants obtained from the decline in INa during step depolarizations were substantially smaller than those obtained using conditioning prepulses to the same potentials and the ratios agreed with previous observations using TTX. Inactivation shifts were also measured and found to be comparable to previous results.     

Pig prothrombin: purification and properties

A procedure for the preparation of highly purified pig prothrombin is described. Compared to the initial clotting activity of the starting plasma, this protein was purified 776 times with a final yield of 8 per cent. The purified zymogen showed a specific activity of 1,460 NH units/mg of protein , a molecular weight of 65,000 as determined by SDS-polyacrylamide disc gel electroesis, E 1.0 mg/ml 1.0 cm, 280 nm = 1.45 at pH 7.0 and the following amino acid composition: Asx 51, Thr 38, Glx 62, Pro 23, Gly44, Ala 25, Half-Cys 30, Val 35, Met 3, Ile 30, Leu 32, Tyr 19, Phe 22, Lys 36, His 8, Arg 28, and Trp 13, which accounts for a minimum molecular weight of 59,370 (carbohydrates not computed). Alanine was found as the only N-terminal residue. Carboxypeptidases A and B failed to release any C-terminal residue. By hydrazinolysis however 0.4 mole of serine was released per mole of prothrombin. The activation of crude and chromatographed pig prothrombin was investigated.     

Determination of phenprocoumon, an anticoagulant, in human plasma

Phenprocoumon is extracted from acidified plasma, the organic phase evaporated, and part of the residue, in ethanol, is quantitatively applied to a thin-layer plate. After separation, the quantity of phenprocoumon is assayed by fluorescence densitometry in situ. Results are reproducible to about 2.5%. The lower limit of detection is 0.1 mg/liter, which makes the method fully applicable to human plasma, because therapeutic concentrations range from 1 to 3 mg/liter. Seven determinations can be made within 3 h. For toxicological purposes, a qualitative analysis can be done in a shorter time, because the phenprocoumon spots are visible under ultraviolet light at 254 nm.     

离子色谱同时测定果汁中22种糖、糖醇和醇

目的建立积分安培-离子色谱法同时测果汁中22种糖、糖醇和醇定的方法。方法在流速为0.40 mL/min, pH值在6.5～8.6,柱温为30℃条件下,在CarboPacTM MA1(4 mm×250 mm)色谱柱中进行分离。结果 22种组分在测定浓度范围内具有良好的线性关系(r~20.999);除了甲醇外,其他21种组分检出限在0.006～0.203 mg/L之间;在0.50、1.00、5.00 mg/L 3个添加浓度水平下,回收率为75.83%～105.89%,相对标准偏差(RSD)在1.03%～10.39%范围内。结论该方法简便、快速、准确、灵敏,完全适于果汁中22种糖、糖醇和醇的分析测定。     

旋光性氰醇的酶催化合成

综述了酶催化立体选择性合成及动力学折分制备旋光性氰醇的几种方法。     

Changes in myocardial hemodynamics and contractile function in patients under surgical treatment for prostatic adenoma

Hemodynamics and left ventricular myocardial contractility in 170 patients who underwent surgery of prostatic adenoma were examined in preoperative period and 16 days after single-stage transvesical adenomectomy. The age of the patients varied from 52 to 85 years. Echocardiography and the dilution method were used for the evaluation. The increase of end-diastolic and end-systolic volumes, stroke volume, cardiac index, was registered. The combined pharmacological treatment made it possible to decrease the number of operative and postoperative cardiovascular complications.     

3,3''-Diindolylmethane induces apoptosis in human cancer cells

Several recent reports presented conflicting data on the action of IL-4 and IL-13 in regulating the release of proinflammatory cytokines by human monocytes. Here we show that the regulation of cytokine release by IL-4 and IL-13 could be either inhibitory or stimulatory in LPS-treated murine peritoneal macrophages. When macrophages were treated with IL-13 or IL-4, between 6 and 24 hr prior to endotoxin challenge, TNF alpha and IL-6 levels were significantly augmented. On the other hand, when the cells were cotreated with LPS plus IL-13 or IL-4, the release of TNF alpha and IL-6 was inhibited. These effects of IL-4 and IL-13 were associated with the modulation of IL-10; pretreatment resulted in a decrease, whereas cotreatment gave rise to a dramatic increase in IL-10 levels. The inhibitory effect of IL-4 and IL-13 on the release of TNF alpha was partially reversed by neutralizing anti-IL10 antibody, and the inhibition of IL-6 release was completely reversed by the antibody. These data suggest that the mechanism of action of IL-13 and IL-4 in modulating macrophage TNF alpha and IL-6 release partially involves IL-10.     

Fenton试剂氧化处理含丙烯腈废水

采用Fenton试剂氧化法处理自制的含丙烯腈(AN)废水(质量浓度为100 mg/L),通过气相色谱法、离子色谱法、元素分析等研究了处理废水产物的组成,并探讨了氧化反应机理。结果表明,在H2O2用量为1～4 mL、FeSO4.7 H2O质量浓度为600 mg/L、初始pH值为1.3～7.0的条件下处理200 mL废水时,AN可以被氧化生成不同状态的产物,其中绝大部分为气体产物,还有一定量的液体产物(含有一定量草酸和少量乙酸、乙醇酸、硝酸根和铵根离子)和固体产物(含C、N等元素的物质),AN转化率超过95%。