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21.
WEIGUANG ZENG PIERRE-OLIVIER REGAMEY KEITH ROSE YUZHOU WANG ERNST BAYER 《Chemical biology & drug design》1997,49(3):273-279
The use of N, O-bisFmoc-N-(2-hydroxy-4-methoxybenzyl) amino acid derivatives in the synthesis of peptides with difficult sequences has already been described. With these amino acid derivatives the reversible protecting group 2-hydroxy-4-methoxybenzyl (Hmb) for the backbone amide bonds of peptide chains is introduced, and thus the aggregation due to hydrogen-bond interchain association is inhibited. This paper describes the synthesis and use of Fmoc-N-(2-hydroxy-4-methoxybenzyl)amino acid derivatives as an alternative means of introducing Hmb backbone protection. These new monoFmoc derivatives were obtained in higher yield than the bisFmoc derivatives. Coupling yields to the amino peptide resin were the same as those obtained with bisFmoc derivatives, under the TBTU/HOBt/DIEA conditions. We also compared different syntheses of a difficult peptide with the Fmoc approach [triple coupling, capping, use of chaotropic agents, backbone protection using monoFmoc (Hmb)Ala] and with optimized Boc chemistry. Both the backbone protection and optimized Boc chemistry approaches gave the desired product in excellent yield and purity. © Munksgaard 1997. 相似文献
22.
RACHEL PHILOSOF-OPPENHEIMER ISRAEL PECHT MATI FRIDKIN 《Chemical biology & drug design》1995,45(2):116-121
The facile thiolytic cleavage of the O-2,4-dinitrophenyl (Dnp) tyrosine bond was applied to the solid-phase synthesis of the 22-amino acid residue peptide H-Asp-Ala-Val-Tyr -Thr-Gly-Leu-Asn-Thr-Arg-Asn-Gln-Glu-Thr-Tyr -Glu-Thr-Leu-Lys-His-Glu-Lys-OH, corresponding to positions 62-83 in the chain of the type 1 receptor for Fcε, domains expressed on the rat mucosal-type mast cells (line RBL-2H3). A method for the spectrophotometric determination of insoluble O-Dnp as well as of unprotected phenolic moieties of tyrosine was developed. It is based on monitoring S-Dnp-2-mercaptoethanol, produced upon O-Dnp thiolysis by 2-mercaptoethanol. © Munksgaard 1995. Dedicated to the memory of Dr. Susumu Funakoshi, a dear friend and a leader in peptide chemistry. 相似文献
23.
The involvement of children in research studies is historically fraught with difficulties. Experiments on children without their consent or knowledge have been carried out in the past and thus the need for stringent ethical control is undoubtedly necessary. However this paper argues that the need to protect children from unethical research has somehow become entwined in the web of secrecy that surrounds the very nature of child abuse. In the name of 'protection' are children in danger of not having their voice heard?
In the foreword to 'Listening to Children' (Alderson, 1995) Roger Singleton writes, 'much research is carried out on and about children, but seldom with children. Children themselves are often strangely silent'. This paper draws on recent literature on the institutional abuse of young people in residential care and the lack of voice that those abused in residential care have traditionally had, suggesting that their silence is not 'strange' but perhaps contrived.
This paper does not repeat the work of Alderson (1995) and make suggestions as to how research with children may best be carried out, but seeks to address the issues in relation to research with children who are in institutions. 相似文献
In the foreword to 'Listening to Children' (Alderson, 1995) Roger Singleton writes, 'much research is carried out on and about children, but seldom with children. Children themselves are often strangely silent'. This paper draws on recent literature on the institutional abuse of young people in residential care and the lack of voice that those abused in residential care have traditionally had, suggesting that their silence is not 'strange' but perhaps contrived.
This paper does not repeat the work of Alderson (1995) and make suggestions as to how research with children may best be carried out, but seeks to address the issues in relation to research with children who are in institutions. 相似文献
24.
1992~1993年间为180例冠脉病变的病人施行冠脉搭桥术,全部病人均采用核甙抑制剂利多氟嗪预处理和低温(28℃)间断缺血心停搏进行术中心肌保护。平均每例病人作冠状动脉端吻合3~4个,每个吻合口用9分钟,主动脉阻断累加时间约25分钟,体外循环时间90分钟,术后医院死亡率1.6%(3/180),无术后心梗发生。作者认为,冠脉搭桥术的术中心肌保护可采用核甙抑制剂和间断缺血心停搏方法,而不用心肌停搏液。 相似文献
25.
利多氟嗪加强间断缺血心停搏心肌的保护作用 总被引:1,自引:1,他引:0
通过对16条犬常温下用利多氟嗪(lidoflazine)预处理加强间断主动脉阻断心停搏心肌保护作用的实验研究。16条犬随机分为对照组和实验组。结果发现,实验组心脏血流动力学的恢复要明显优于对照组。二组间心肌组织ATP、腺苷和肌苷以及冠脉回流液中CPK、CPK-MB、LDH、SOD和MDA值均有显著性差异(P>0.05)。作者认为,冠脉搭桥术中采用间断缺血心停搏时加用利多氟嗪有利于保存心肌能量,减轻心肌再灌注损伤和术后迅即恢复心脏功能。 相似文献
26.
为了探讨常温体外循环下采用缺血预调行心肌保护的研究,通过建立犬的常温体外循环全心缺血预调模型,旨在探讨心内直视手术缺血预调保护心肌的可能性。预调组采用升主动脉阻断5分钟,放开10分钟,反复三次的方式预调心脏;对照纽简单并行循环45分钟,而后两组均接受30分钟缺血和60分钟再灌注。结果显示,预调组室颤发生率低(16.7 VS 83.3%P=0.04),无再灌注心律失常(0 VS66.7%P=0.03),心肌ATP消耗减慢(4.69 1.050 VS 2.35±0.86μmol/g wet wt P<0.01),乳酸积累减少(4.49±0.86 VS 9.80 5.53mg/g wet wtP<0.05),心肌细胞超微结构损伤轻。结论:常温体外循环下应用缺血预调保护犬的心肌是可行而有效的。 相似文献
27.
28.
Jan E. Zejda Thomas S. Hurst Ernest M. Barber Charles Rhodes James A. Dosman 《American journal of industrial medicine》1993,23(5):743-750
A cross-sectional survey on respiratory health in swine producers showed that 30% of 301 examined men usually used a dust mask when working inside a barn. They did not differ significantly from dust mask nonusers in respect to respiratory symptoms and lung function. This analysis was undertaken to determine whether the respiratory health of dust mask users was associated with reasons why they had started individual respiratory protection. The subjects were recontacted in order to identify those who started using a mask to deliberately prevent symptoms (42 men) and those who started protection because of pre-existing respiratory symptoms (44 men). Not unexpectedly, betweengroup comparisons of respiratory symptoms and lung function suggest that swine producers who wear dust masks for preventive purposes have better respiratory health than those who wear dust masks because of symptoms or those who do not use individual respiratory protection. The individual reasons for starting dust mask usage should be examined among potential determinants of the outcomes of prospective studies which can then provide more valid assessment of the effect of individual respiratory protection. © 1993 Wiley-Liss, Inc. 相似文献
29.
30.
Patricia H. Arford 《Journal of nursing scholarship》2004,36(3):265-271
PURPOSE: To provide a primer for novice nurse scientists about the increasingly regulated human research environment. ORGANIZING CONSTRUCTS: Federal regulations and international guidelines about protection of human research participants are discussed, with particular attention to institutional review boards for human research. CONCLUSION: Understanding the processes used by institutional review boards to foster ethical human research promotes collaborative interactions and supports compliant research work. 相似文献