Y-Anti effect

Carbon substituents directly attached to a double bond experience pronounced shielding y-effects in the Z configuration (see Section 4.1.1.1.), as shown for (E)- and (Z)-3-hexene. In the Z-isomer the a-carbon experiences a typical y-syn effect from the other a-carbon, whereas the corresponding y-anti effect in the If-isomer is negligible. 

This y-anti effect is significantly reduced in the cyclobutane or cyclopentane fused ring systems 18-23, since the p character of these orbitals is decreased markedly. 

Some other mechanisms will be discussed in later sections The Grant-Cheney formulation (88) of steric compression effects will appear in the context of y-gauche substituent effects (Section III-C), and hyperconjugative orbital interactions will be cited in interpretations of y-anti substituent (Section III-D) and intramolecular interaction effects (Section IV). 

Of all substituent effects, that caused by y-anti substituents has been the hardest to understand in terms of transmission mechanisms, notably because the resulting shifts are sometimes upfield and sometimes downfield. So, for example, y -SCS(OH) values range from about +6 (208) to —6 (209). Correspondingly, the discussion about transmission mechanisms is prone to speculation and controversy. At present it is impossible to arrive at a consistent interpretation of this substituent effect there is no choice but to compile a number of molecular properties that apparently affect the transmission of substituent influences on antiperiplanar carbon atoms. 

C(21) nuclei. (226) In addition [367] shows the marked y-anti-periplanar effect of the nitrogen atom on the C(19) shift [cf. C(16) shift]. (227)... 

Makino, T., Furuta, Y., Wakushima, FI., Fujii, FI., Saito, K., and Kano, Y. Anti-allergic effect of Perilla frutescens and its active constituents. Phytother Res, 17(3), 240-243, 2003. 

In the 1980s, studies with EAE, an animal model mimicking MS, indicated that interferon y (IFN y) was effective in treating that disease and a trial was initiated to evaluate its potential benefit in human MS. Rather than showing efficacy, in 1987, use of IFNy as a therapy in MS patients caused an increase in clinical exacerbations and forced the clinical trial to terminate early (Panitch et al., 1987). Associated study of IFNy in 20 MS patients indicates increased concentrations of IFNy and TNFa precede the observation of clinical defects (Beck et al., 1988). An evaluation of primary RR-MS patient lymphocytes using flow cytometry supports a correlation between EDSS scores and IFNy secretion (Petereit et al, 2000). Intracellular cytokine immuno-staining of anti CD8-I- T cells reveals a correlation with IFNy and disease phase but not disease activity (Becher et al., 1999). What initially seemed efficacious in the EAE animal model, not only did not decrease MS symptoms but is now felt to be a marker of active inflammatory disease. 

Onuma, M. Yasutomi, Y. Yamamoto, M. Watarai, S. Yasuda, T. Kawakami, Y. Antitumor effect of adriamycin entrapped in liposomes conjugated with anti-bovine tumor antigen monoclonal antibody in leukemic cows. Zentralbl. Veterinarmed. 1989, 36, 139-147. 

Harada, N., Takabayashi, F., Oguni, I., and Hara, Y., Anti-promotion effect of green tea extracts on pancreatic cancer in golden hamster induced by N-nitroso-bis(2-oxopropyl)amine, Int Symp. TeaSci., Japan, 200-204, 1991. 

Zhu, Y, Hu, J. L., Yeung, Y. (2009), Effect of soft-segment crystallization, hard-segment physical cross-link on shape memory function in anti-bacterial segmented PU ionomers, Acta Biomaterials, 19, 3346-57. 

Various pharmacologic and therapeutic drugs have been tested to prevent or treat myopa y. Drugs effective in the treatment of neuromuscular signs of anti-ChE toxicity include (i) oximes that reactivate the phosphorylated AChE (Thiermann et al., 2005 Marrs and Vale, 2006), (ii) subparalyzing and paralyzing doses of rf-tubocura-rine (Clinton and Dettbam, 1987 Patterson et al., 1987),... 

Anomeric effect (Section 25 8) The preference for an elec tronegative substituent especially a hydroxyl group to oc cupy an axial orientation when bonded to the anomeric carbon m the pyranose form of a carbohydrate Anti (Section 3 1) Term describing relative position of two substituents on adjacent atoms when the angle between their bonds is on the order of 180° Atoms X and Y m the structure shown are anti to each other... 

Administration of lL-12 before lethal y-kradiation of mice protects against hemopoietic death and increases the number of BM cells at six days after kradiation, but sensitizes for G1 injury (189). The protective effects are abrogated by anti-lL-1 receptor or anti-SCE antibodies but not by anti-lEN- y antibodies. The sensitizing effect of lL-12 may be due to its abiUty to prime for TNE and lL-6, and can be aboHshed by anti-lEN antibody. 

IFN- 3 reduces the induction by inflammatory cytokines of adhesion molecules and of MHC class I and II complex on endothelial cells, a process preceding attachment and transendothelial migration of T-cells. These anti-inflammatory effects of IFN- 3 exemplify antagonistic actions of type I and type IIIFN. There is, indeed, much clinical evidence for the involvement of IFN-y in inflammatory processes - through activation of iNOS and subsequent secretion of NO - leading to the establishment of autoimmune diseases as for instance in rheumatoid arthritis. 

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