湿法纺制PEI／PES中空纤维气体分离共混膜

采用湿法纺丝工艺纺制了聚醚酰亚胺（ＰＥＩ）－聚苯醚砜（ＰＥＳ）中空纤维Ｈ２－Ｎ２和Ｈｅ－Ｎ２分离共混膜,得到Ｈ２和Ｈｅ的渗透通量及选择性为：ＪＨ２＝３６０ＧＰＵ,αＨ２／Ｎ２＝１６２,ＪＨｅ＝１８１ＧＰＵ,αＨｅ／Ｎ２＝７６．７;研究了芯液组成及其流量对膜性能的影响。通过扫描电镜,分析了中空纤维膜的结构,讨论了膜制备过程中的相转化原理。     

卟啉生物化学研究概况

本文在卟啉的化学结构和分类、化学检测方法、化学合成以及卟啉生物合成等方面对卟啉生物化学的研究概况进行综述。     

自发性高血压大鼠血管结构与功能的观察

观察１６周龄ＳＨＲ大鼠与同龄ＷＫＹ大鼠之间血管结构与功能的差异及其在高血压形成中的作用。用尾袖法测量大鼠动脉血压,动脉环实验测定主动脉与肠系膜动脉血管平滑肌的反应性,用肉眼数点计算法测定主动脉中膜腔壁厚度／管腔面积（Ｗ／Ｌ）,图像分析仪摄像求积法测定肠系膜动脉Ｗ／Ｌ。结果：１６周龄ＳＨＲ大鼠血压明显高于ＷＫＹ大鼠（２８．２４±１．１２ｋＰａ与１７．１５±０．７５ｋＰａ,Ｐ＜０．０５）。ＳＨＲ大鼠主动脉和肠系膜动脉的Ｗ／Ｌ明显大于ＷＫＹ大鼠（０．３３±０．０３与０．２４±０．０５,Ｐ＜０．０５;及０．７５±０．０９与０．２６±０．０２,Ｐ＜０．０５）。硝普钠引起的ＳＨＲ大鼠血管舒张率明显低于ＷＫＹ,而去甲肾上腺素引起的ＳＨＲ大鼠血管收缩率明显高于ＷＫＹ。结果表明：ＳＨＲ大鼠阻力血管结构的改变可能是高血压形成的重要因素,ＳＨＲ大鼠血管功能改变与高血压形成密切相关。     

具强杀菌活性的兔Ⅱ型磷脂酶A2互补DNA克隆及其顺序确定的研究

目的:确定具强杀菌活性的兔Ⅱ型磷脂酶A2(PLA2)cDNA和蛋白质的一级结构,了解其杀菌功能与蛋白质一级结构的关系.方法:用PCR方法从兔骨髓cDNA库中克隆出Ⅱ型磷脂酶A2 cDNA并确定DNA顺序,推断出它的蛋白质一级结构;并与其它一些动物PLA2的结构进行比较.结果:成功获得了该磷脂酶A2的cDNA和蛋白质一级结构.它是目前上百种已知蛋白质一级结构的磷脂酶A2中碱性最强的蛋白,氨基酸组成中碱性氨基酸较丰富.其它具杀菌活性的哺乳动物Ⅱ型磷脂酶A2也都是碱性强的蛋白.结论:磷脂酶A2一级结构中富于碱性氨基酸是其具有杀菌功能的关键,而杀菌活性的强弱与其分子碱性强度呈正相关.     

Identification of amino-terminal sequences contributing to tryptophan hydroxylase tetramer formation

Tryptophan hydroxylase (TPH) catalyzes the rate-limiting step in the biosynthesis of serotonin. In the rabbit, TPH exists as a tetramer of four identical 51-kDa subunits comprised of 444 amino acids each. The enzyme consists of an amino-terminal regulatory domain and a carboxyl-terminal catalytic domain. Previous studies demonstrated that within the carboxyl-terminus of TPH, there resides an intersubunit binding domain (a leucine zipper) that is essential for tetramer formation. However, it is hypothesized that a 4,3-hydrophobic repeat identified within the regulatory domain of TPH (residues 21–41) may also be involved in macromolecular assembly. To test this hypothesis, a series of amino-terminal deletions (NΔ15, 30, 41, and 90) were created and assessed for macromolecular structure using size-exclusion chromatography. The amino-terminal deletion NΔ15, upstream from the 4,3-hydrophobic repeat, was capable of forming tetramers. However, when a portion of the 4,3-hydrophobic repeat was deleted (NΔ30), a heterogeneous elution pattern of tetramers, dimers, and monomers was observed. Complete removal of the 4,3-hydrophobic repeat (NΔ41) rendered the enzyme incapable of forming tetramers; a monomeric form predominated. In addition, a double-point mutation (V28R-L31R) was created in the hydrophobic region of the enzyme. The introduction of two arginines (R) at positions 28 and 31 respectively, in the helix disrupted the native tetrameric state of TPH. According to size-exclusion chromatography analysis, the double-point mutant (V28R-L31R) formed dimers of 127 kDa. Thus, it is concluded that there is information within the amino-terminus that is necessary for tetramer formation of TPH. This additional intersubunit binding domain in the amino-terminus is similar to that found in the carboxyl-terminus.     

Rape attitudes amongst British medical students

OBJECTIVES: To examine the rape attitudes of a sample of 252 British medical students. DESIGN: A 20-item questionnaire was used. SETTING: A London medical school. SUBJECTS: Fourth-year medical students. RESULTS: In general, students were well informed on legal and factual issues regarding rape and sexual assault. However, significant differences were found in the attitudes to rape between males and females. Female students were significantly more positive in their responses to victims. CONCLUSIONS: These results support findings from previous studies of rape attitudes in other professional groups. Better knowledge and enlightened attitudes amongst health care staff can have a significant impact on the management of sexual assault and influence the likelihood of victims presenting for treatment. In conclusion, this study emphasizes the importance of teaching about sexual violence in British medical schools.     

A comparative view of Rickettsia tsutsugamushi and the other groups of rickettsiae

Recent researches on the rickettsial group microorganisms are summarized in their comparative aspects of morphology, cultivation and multiplication, susceptibility to chemotherapeutics, chemical structure of envelopes, nucleic acid, protein constitution, and gene structures. From this overview, Rickettsia tsutsugamushi seems to have different properties from the others and should be reclassified into a new genus, and a new species name as Orientia tsutsugamushi is proposed.Presented at the 4th International Symposium on Rickettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

X-Ray Structure and Crystal Lattice Interactions of the Taxol Side-Chain Methyl Ester

A colorless, parallelepiped crystal of methyl (2R,3S)-N-benzoyl-3-phenylisoserinate belonging to the space group P2_l with a = 5.414(4), b = 7.813(1), c = 17.802(7) , = 90.87(4)°, Z = 2, V = 752.9 ³, D _calc = 1.32 g cm^–3, and µ_calc = 1.02 cm^–1 was selected and the structure solved using direct methods. Refinement led to a final R = 0.079 for 819 [F _o 5(F_o)] reflections. Intermolecular hydrogen-bonding interactions are prevalent in the crystal lattice of this compound.     

Study of the substructure of the Morgagni and Brunescens cataract with the TAO non-coating technique

Lens tissue from a Morgagni cataract was examined by SEM and TEM. For SEM, after prefixation with glutaraldehyde and postfixation with the tannic acid/arginine/OsO₄ non-coating (TAO) technique, and for TEM, after prefixation with glutaraldehyde, postfixation with OsO₄/K₄Fe(CN)₆ and poststaining with uranyl acetate/lead citrate. The TAO technique seems to be a particularly suitable postfixation method for the SEM investigation of cararact tissue because of the presence of the protein structures present. The cortical region showed areas of radially, instead of concentrically, arranged lens fibres, degenerated lens fibres with holes (vacuoles), broken ball and socket connections between the lens fibres, and oval or spherical structures varying in size from 0.5–20 m, the largest resembling a golfball, arising from the cytoplasm of degenerating lens fibres. The smallest, 0.2–0.5 m, appear to have been expelled from the furrowed lens epithelium.