基础内分泌学讲座(Ⅳ)

睾丸在生殖方面有两个独立而有联系的功能:即产生和储存有活力的精子;合成与分泌雄激素。 睾丸是成对的腺体,是由精细管及间质组织构成。间质组织中含有丰富的血管和淋巴管,精细管的上皮及所有组份,通过扩散的方     

基础内分泌学讲座(Ⅰ)

因为观点不同,对内分泌学下一个完整的、明确的、为所有生物学家能接受的定义是很困难的。现有两派主张,一派认为,内分泌学是通过化学途径调整机体的生物学。根据这一观点,存在于体液中的一切化学调节因素都包括在内分泌学的研究范围;另一派学者则遵循贝利斯(Bayliss)和斯塔林(Starling)的经典概     

基础内分泌学讲座(Ⅲ)

一、胰岛 1869年兰格汉斯(Langerhans)首先发现,在胰腺中有一小簇具有丰富血管支配的细胞,这些细胞不同于分泌胰液的腺泡,没有分泌导管,称作Langerhans氏小岛或胰岛。人的胰腺含有200百万个胰岛,广泛地散布在胰腺组织内,直径为20—30微米,全部胰岛组织只占胰腺重量的1—2％。胰岛是胰腺的内分泌组织,它包含3种内分泌细胞,各自分泌不同激素。α     

基础内分泌学讲座(V)哺乳动物的妊娠子宫与胎盘的分泌功能

一、胎盘 在哺乳动物妊娠期间,内分泌功能系统开始了巨大的变化。内分泌腺体尤其是垂体与卵巢的分泌活动亦出现了一系列相应的反应,发育中的妊娠子宫与胎盘则是此时形成重要激素的来源。许多哺乳动物在妊娠子宫内膜中,有产生激素的腺体结构。胎盘及内膜合成的部分激素是真正的妊娠激素,而且这些激素主要是在雌性有机体中形成。因此,它们在维持正常妊娠过程中起着相当重要的作用。此外,还有垂体促性腺素和来源于卵巢及肾上腺皮质的类     

神经内分泌讲座(一)——神经内分泌学研究的历史与现状

神经内分泌学是神经学和内分泌学之间的一门边缘学科。它主要是研究神经系统与内分泌系统之间的相互关系,例如,神经系统怎样调节内分泌系统的活动,特别是下丘脑如何调节垂体的活动;下丘脑与脑的其它部位的结构与功能联系;内分泌系统的激素对中枢神经系统的影响等。半...     

A Mn(II)–Mn(II) center in human prolidase

Human prolidase, the enzyme responsible for the hydrolysis of the Xaa-Pro/Hyp peptide bonds, is a key player in the recycling of imino acids during the final stage of protein catabolism and extracellular matrix remodeling. Its metal active site composition corresponding to the maximal catalytic activity is still unknown, although prolidase function is of increasing interest due to the link with carcinogenesis and mutations in prolidase gene cause a severe connective tissue disorder. Here, using EPR and ICP-MS on human recombinant prolidase produced in Escherichia coli (hRecProl), the Mn(II) ion organized in a dinuclear Mn(II)–Mn(II) center was identified as the protein cofactor. Furthermore, thermal denaturation, CD/fluorescence spectroscopy and limited proteolysis revealed that the Mn(II) is required for the proper protein folding and that a protein conformational modification is needed in the transition from apo- to Mn(II)loaded-enzyme. The collected data provided a better knowledge of the human holo-prolidase and, although limited to the recombinant enzyme, the exact identity and organization of the metal cofactor as well as the conformational change required for activity were proven.     

科学讲座高级神经活动生理学基础(十三) 巴甫洛夫学说的发展

巴甫洛夫的条件反射学说在20世纪的发生与发展并不是俄国和世界科学中的偶然现象,它是由自然科学和哲学的先进成就所准备好了的,它有其所由产生的实际基础。但是要使可能变成现实还必须有巴甫洛夫这样一位伟大的天才家。 19世纪俄国唯物主义哲学家的著作继承了并发展了自然科学中的唯物主义原则,非常重视人的心理活动及其对外界环境的依赖性的问题。这些著作促使自然科学家用唯物主义观点去研究人和动物心理活动的问题,对于形成条件反射学说的作用是重要的。巴甫洛夫在他的     

Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 3′AMP and 2′AMP

Derivatives of Co(II), Ni(II), Cu(II) and Zn(II) with 3′AMP and 2′AMP were synthesized and characterized by IR UV-Vis and fluorescence spectroscopy. There seems to be bonding of the metal ion to the base in all cases. The activation test, using the complexes as allosteric labels, was carried out with rabbit muscle glycogen phosphorylase b, but the enzyme was not activated, confirming that the phosphate group must necessarily be bonded to position 5′ of the ribose in order to activate this enzyme.     

Free metal ion depletion by “good's” buffers: II. N-(2-acetamido)-2-aminoethanesulfonic acid (ACESH): Complexes with Calcium(II), Magnesium(II), Manganese(II), Cobalt(II), Zinc(II), Nickel(II), and Cooper(II)

Potentiometric, visible, and infrared studies of the complexation of N-(2-acetamido)-2-aminoethanesulfonic acid (ACESH) by Ca(II), Mg(II), Mn(II), Co(II), Zn(II), Ni(II), and Cu(II) are reported. Ca(II), Mg(II), and Mn(II) were found not to complex with ACES^?, while Co(II), Zn(II), Ni(II), and Cu(II) were found to form 2:1, ACES^? to M²⁺, complexes, and [Cu(ACES)₂] was found to undergo stepwise deprotonation of the amide groups to form [Cu(H_?1ACES)₂^2?]. Formation (affinity) constants for the various metal complexes are reported, and the probable structures of the various metal chelates in solution are discussed.     

Binuclear metal complexes. 59. Synthesis and magnetism of dicopper(II) and copper(II)-nickel(II) complexes with N,N′-ethylenedisalicylamidatocuprate(II)

The complexes [Cu(samen)Cu(L)] and [Cu(samen)Ni(L)₂] (Lbpy, phen) have been synthesized by the reaction of sodium N,N′-ethylenedisalicylamidatocuprate(II) pentahydrate (Na₂- [Cu(samen)]·5H₂O), a divalent metal ion, and 2,2′- dipyridyl or 1,10-phenanthroline. Cryomagnetic data for the CuCu complexes did not fit the Bleaney- Bowers equation; but the data did fit a modified Bleaney-Bowers equation

with a large negative J and a significant negative θ, suggesting that a considerable magnetic interaction operates between essentially planar [Cu(samen)Cu(L)] molecules. The magnetisms of the CuNi complexes were well interpreted in terms of the susceptibility equation based on the Heisenberg model. An antiferromagnetic spin-exchange interaction (J= −13∼−14 cm⁻¹) was suggested between the metal ions.     

生物统计基础知识(II)

二、两个样本平均数的比较在一次饲料实验中,测定了饲以不同等级蛋白质饲料的两组大白鼠八周后的增重量。一组白鼠饲以高蛋白,平均增重量为120克;另一组白鼠饲以低蛋白,平均增重量为101克。这     

Synthesis, Characterization and Antitumor Studies of Mn(II), Ni(II), Cu(II) and Zn(II) Complexes of N-Nicotinoyl-N′-o-Hydroxythiobenzhydrazide

A new ligand N-Nicotinoyl-N-o-hydroxythiobenzhydrazide (H₂Notbh) forms complexes [Mn(Notbh)(H₂O)], [M(Notbh)] [M=Ni(II) Cu(II) and Zn(II)] which were characterized by various physico-chemical techniques. All the metal complexes were observed to inhibit the growth of tumor in vitro, whereas, ligand did not. In vivo administration of these complexes resulted in prolongation of survival of tumor bearing mice. Tumor bearing mice administered with metal complexes showed reversal of tumor growth associated induction of apoptosis in lymphocytes. The paper discusses the possible mechanisms and therapeutic implication of the H₂Notbh and its metal complexes in tumor regression and tumor growth associated immunosuppression.     

Synthesis and characterization of β-diketiminate germanium(II) and tin(II) bromides

The equimolar reaction of a β-diketiminate lithium salt LLi(OEt₂) [L = HC(CMeNAr)₂; Ar = 2,6-iPr₂C₆H₃] with either GeBr₂ or SnBr₂ in diethyl ether affords the synthetically useful monomeric β-diketiminate-element halides LGeBr (1) and LSnBr (2), respectively. Both are soluble in hydrocarbon solvents, stable in inert atmosphere, and have been characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction analysis.