硫酸多粘菌素B提取工艺的研究进展

硫酸多粘菌素B是一种碱性多肽类抗生素.由于其对产NDM-1细菌(超级细菌)具有较高体外敏感性,因此,引起了人们的广泛关注.但其结构复杂、稳定性差,在工业上分离纯化的难度很大.本文主要对硫酸多粘菌素B的提炼方法进行了综述和讨论.     

复合维生素B注射液细菌内毒素检查法的研究

目的建立复合维生素B注射液的细菌内毒素检查方法。方法根据《中国药典》2005年版二部附录细菌内毒素检查法,采用2个不同生产厂家的鲎试剂对复合维生素B注射液进行研究。结果复合维生素B注射液最小不干扰稀释倍数为1∶16,细菌内毒素限值为5 EU.ml-1。结论采用细菌内毒素检查法控制复合维生素B注射液的质量是可行的。     

注射用维生素B6细菌内毒素检查法的研究

目的建立注射用维生素B6的细菌内毒素检查方法。方法根据中国药典2010年版二部附录细菌内毒素检查法,采用2个不同厂家的鲎试剂对注射用维生素B6进行研究。结果注射用维生素B6细菌内毒素检查限值为0.30 EU.mg 1,其最大不干扰浓度为0.208 mg.mL 1,用灵敏度为0.06 EU.mL 1或更高灵敏度的鲎试剂可进行检验。结论细菌内毒素检查法可用于注射用维生素B6中内毒素的检查。     

维生素B6注射液细菌内毒素的检测

目的建立凝胶法进行维生素B6注射液中细菌内毒素检查的方法.方法用不同厂家的鲎试剂对不同批号的维生素B6注射液分别进行干扰试验,考察确立维生素B6注射液中细菌内毒素检测法.结果维生素B6注射液样品浓度在0.25mg·mL-1以下时可消除干扰,其细菌内毒素限值可定为1EU·mL-1.结论可以用细菌内毒素检查法(凝胶法)对维生素B6注射液进行检查.     

弃G因子鲎试剂检测注射用香菇多糖细菌内毒素优势

目的:研究弃G因子鲎试剂(B、C试剂)检测注射用香菇多糖细菌内毒素的效果。方法:参照中国药典2005版二部附录细菌内毒素检查法,分别用全成分鲎试剂和弃G因子鲎试剂做香菇多糖的细菌内毒素检测实验。结果:弃G因子鲎试剂检测结果灵敏、准确可靠,不出现假阳性反应。结论:弃G因子鲎试剂检测注射用香菇多糖的细菌内毒素是一种较好的方法。     

维生素B6注射液的细菌内霉素检查方法的探析

目的：根据实验建立用于维生素B6类注射液的细菌内霉素检测法。方法：采用两个厂家的6个批号的维生素B6类注射液样品分别与两个厂家的鲎试剂进行干扰实验,观察并确立该样品的细菌内霉素检查方法。结果：维生素B6注射液对细菌内霉素检查方法的干扰作用在浓度低于0.500mg/mL时消除。结论：细菌内霉素检查方法对于维生素B6注射液的细菌内霉素限定值为0.5EU/mg。     

金属β-内酰胺酶研究进展

金属β-内酰胺酶是β-内酰胺酶中的B亚群,带有该酶的细菌表现为碳青霉烯类抗生素的耐药,该基因可通过染色体和转移基因在不同种细菌间传递,造成广泛耐药。本篇综述从金属β-内酰胺酶的分类、分子结构、抑制剂,检测方法,流行病学特点和MBL阳性的革兰阴性杆菌感染的处理等方面加以阐述。     

细菌内毒素检查法影响因素分析

细菌内毒素检查法是利用鲎试剂与细菌内毒素产生凝集反应的机制以判断供试品中细菌内毒素的限量是否符合规定的一种方法.<中国药典>2000年版收载了47种药品的细菌内毒素检查,此法已较广泛地应用于药品质量控制.笔者在实践中有针对性地收集、研究分析此法中的有关影响因素,现总结如下.     

“超级细菌”NDM-1的发现及研究进展

近日,“超级细菌”掀起了即甲型H1N1流感后全球的又一新“浪潮”,引起人们的一阵恐慌.“超级细菌”是具有多重耐药性细菌的总称,NDM-1是细菌携带的一种抗性基因,具有极强的耐药性,能水解几乎所有的β-内酰胺类抗生素,该细菌属一种新型的“超级细菌”.目前临床治疗受到极大的威胁,新型抗生素的研发迫在眉睫.本文就其发现、特点...     

介绍一种改量的粪便细菌基因组DNA提取试验方法

目的 观察改变细菌裂解温度对提取粪便细菌基因组DNA量和纯度的影响.方法 收集10例肝硬化患者粪便,每例患者粪便等分成两份,再随机分成两组.采用QIAamp DNA Stool Mini Kit试剂盒（国际通用粪便细菌基因组DNA提取试剂盒）进行抽提,一组（A组）按照试剂盒说明书温度要求进行粪便细菌基因组DNA提取,一组（B组）对试剂盒细菌裂解温度改良后再进行提取.结果 与按照试剂盒说明书温度进行提取组相比,改变细菌裂解温度后粪便基因组DNA提取量明显增高（P〈0.05）,而粪便基因组DNA提取纯度（OD260/280、OD260/230）无明显变化（P〉0.05）.结论 改变细菌裂解温度能明显提高粪便细菌基因组DNA提取量,而不改变粪便细菌基因组DNA的提取纯度.该方法可以解决因粪便采样量少导致粪便基因组DNA提取量不足的问题.     

Kinin B1 receptor homo-oligomerization is required for receptor trafficking to the cell surface

The kinin B1 receptor (B1R) is a G protein-coupled receptor with pro-inflammatory activity that is latent in healthy tissues but induced by tissue insult. Here, we investigated if B1R homo-oligomerization is a possible mechanism regulating the presentation of this receptor at the level of maturation and trafficking to the cell surface. To this end, we used HEK293 cells stably expressing N-terminal FLAG and HA epitope-tagged wild-type human B1R and an N-terminal receptor fragment, B1stop135, which terminates at the C-terminal end of the third transmembrane domain and has previously been shown to oligomerize with B1R. Receptors were monitored by immunoblotting and immunoprecipitation, receptor function by agonist binding and agonist-promoted phosphoinositide hydrolysis, and receptor trafficking by confocal immunofluorescence microscopy. When expressed alone, B1R is core N-glycosylated and forms oligomers localized intracellularly and on the cell surface. B1stop135 also exists as core N-glycosylated oligomers but is localized exclusively intracellularly. When co-expressed, B1stop135 prevents specifically B1R homo-oligomerization by forming nonfunctional B1R-B1stop135 hetero-oligomers, retains B1R intracellularly at least in part in the endoplasmatic reticulum (ER), increases calnexin binding to the receptor, and increases receptor degradation. We conclude that B1R homo-oligomerization is necessary for B1R maturation and trafficking to the cell surface. Modulating this mechanism may be a novel therapeutic avenue in inflammatory disease.     

人肝脏细胞色素P450 2B6催化药物生物转化研究进展

CYP 2B6是细胞色素P450 2B亚家族中的主要成员,参与催化多种内源、外源化合物,特别是多种临床药物的生物转化.本文综述了CYP 2B6的表达、催化药物生物转化及基因多态性的研究进展.     

Selective Phosphodiesterase 4B Inhibitors: A Review

Phosphodiesterase 4B (PDE4B) is a member of the phosphodiesterase family of proteins that plays a critical role in regulating intracellular levels of cyclic adenosine monophosphate (cAMP) by controlling its rate of degradation. It has been demonstrated that this isoform is involved in the orchestra of events which includes inflammation, schizophrenia, cancers, chronic obstructive pulmonary disease, contractility of the myocardium, and psoriatic arthritis. Phosphodiesterase 4B has constituted an interesting target for drug development. In recent years, a number of PDE4B inhibitors have been developed for their use as therapeutic agents. In this review, an up-to-date status of the inhibitors investigated for the inhibition of PDE4B has been given so that this rich source of structural information of presently known PDE4B inhibitors could be helpful in generating a selective and potent inhibitor of PDE4B.     

The GABA(B2) subunit is critical for the trafficking and function of native GABA(B) receptors

Studies in heterologous systems have demonstrated that heterodimerisation of the two GABA(B) receptor subunits appears to be crucial for the trafficking and signalling of the receptor. Gene targeting of the GABA(B1) gene has demonstrated that the expression of GABA(B1) is essential for GABA(B) receptor function in the central nervous system (CNS). However, the contribution of the GABA(B2) subunit in the formation of native GABA(B) receptors is still unclear, in particular whether other proteins can substitute for this subunit. We have created a transgenic mouse in which the endogenous GABA(B2) gene has been mutated in order to express a C-terminally truncated version of the protein. As a result, the GABA(B1) subunit does not reach the cell surface and concomitantly both pre- and post-synaptic GABA(B) receptor functions are abolished. Taken together with previous gene deletion studies for the GABA(B1) subunit, this suggests that classical GABA(B) function in the brain is exclusively mediated by GABA(B1/2) heteromers.     

Phosphodiesterase 4B2 is the predominant phosphodiesterase species and undergoes differential regulation of gene expression in human monocytes and neutrophils.

The type 4 phosphodiesterase (PDE4) is the predominant PDE isozyme in various leukocytes and plays a key role in the regulation of inflammatory cell activation. There are four PDE4 subtypes (A, B, C, and D), and within each subtype, there are multiple variants. Very recently, we found in monocytes that PDE4B gene expression is selectively induced by lipopolysaccharide (LPS) and that the induction is inhibited by interleukin (IL)-10 and IL-4. In this study, we show that the PDE4B gene is constitutively expressed in neutrophils and that this expression remains unaffected by LPS or IL-10. PDE4B is the predominant subtype in neutrophils and in unstimulated or LPS-stimulated monocytes, and in these cells, the PDE4B2 variant is the only detectable molecular species of PDE4B. Therefore, PDE4B2 is the predominant PDE isoform in human neutrophils and monocytes, and its expression is regulated differently by these two cell types. Furthermore, leukocytes are the most dominant source of PDE4B2, suggesting that PDE4B2 is a relatively specific target for discovering anti-inflammatory drugs.     

Hepatitis B

Hepatitis B remains a major public health problem around the world. The discovery of the hepatitis C virus has diverted interest from hepatitis B to this new virus and the epidemic associated with it, but hepatitis B remains a significant pathogen for millions of people worldwide. The World Health Organization has suggested that universal vaccination of children against hepatitis B should be implemented in an attempt to reduce the enormous morbidity and mortality associated with infection of this virus group. The review seeks to identify all the newer discoveries relating to hepatitis B that have been made in the past decade. Reference is made to the appearance of hepatitis B mutants which are able to infect patients previously infected with the wild strain of the virus. The implications of mutants on vaccination programmes is raised, as are issues relating to treatment of hepatitis B infection.     

High-affinity binding of peptide agonists to the human B1 bradykinin receptor depends on interaction between the peptide N-terminal L-lysine and the fourth extracellular domain of the receptor

The aim of this study was to identify the location of the N terminus of peptide agonist ligands when bound to the human B1 bradykinin (BK) receptor. To reach this aim, we exploited the fact that high-affinity binding of kinin peptides to the human B1 receptor subtype requires a peptide N-terminal L-Lys, whereas high-affinity binding to the B2 receptor subtype does not require this residue. This was done by comparing the affinities of BK, a B2 receptor-selective peptide, and kallidin or Lys-BK, a less receptor-selective peptide, for chimeric proteins in which each B1 receptor domain had been substituted in the human B2 receptor and expressed in HEK293 cells. Individual substitution of transmembrane domains 1-7 (TM-I-VII) and extracellular domains 1-4 (EC-I-IV) of the B1 receptor in the B2 receptor influenced the affinities of BK and Lys-BK approximately equally. In contrast, substitution of B1 EC-IV dramatically reduced the affinity and potency of BK, whereas these parameters for Lys-BK were essentially unaltered. Substitution of either the N- or C-terminal half of B1 EC-IV in the B2 receptor only had a limited effect on the peptide binding constants, indicating the involvement of multiple residues throughout this domain. Complementary mutations of the N-terminal residue in Lys-BK revealed that both the positive charge and the proper spatial orientation of this residue were required for interaction with B1 EC-IV. Thus, the N-terminal residue of peptide agonists when bound to the human B1 receptor is positioned extracellularly and interacts with EC-IV.     

A New Method for Estimating Dermal Absorption from Chemical Exposure: 2. Effect of Molecular Weight and Octanol-Water Partitioning

A new method for estimating dermal absorption including the effects of exposure time and chemistry is described generally in Part 1 of this series. This method accounts for the larger absorption rates during the initial exposure period as well as the hydrophilic barrier which the viable epidermis presents to lipophilic chemicals. A key parameter in this procedure, the ratio of the stratum corneum and epidermis permeabilities (B) depends on molecular weight and octanol-water partitioning. Several approaches for approximating B and its affect on the dermal absorption prediction are discussed here. Generally, the parameter B is only important for highly lipophilic chemicals which also have relatively small molecular weights. When B is important, the recommended prediction for B is based on the Potts and Guy correlation for human stratum corneum permeability.