抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

6.2.2. Definition of Effective Properties 3064 6.3. Response Properties to Magnetic Fields 3066 6.3.1. Nuclear Shielding 3066 6.3.2. Indirect Spin−Spin Coupling 3067 6.3.3. EPR Parameters 3068 6.4. Properties of Chiral Systems 3069 6.4.1. Electronic Circular Dichroism (ECD) 3069 6.4.2. Optical Rotation (OR) 3069 6.4.3. VCD and VROA 3070 7. Continuum and Discrete Models 3071 7.1. Continuum Methods within MD and MC Simulations 3072

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Quantum mechanical continuum solvation models.

The 11th edition of Harrison's Principles of Internal Medicine welcomes Anthony Fauci to its editorial staff, in addition to more than 85 new contributors. While the organization of the book is similar to previous editions, major emphasis has been placed on disorders that affect multiple organ systems. Important advances in genetics, immunology, and oncology are emphasized. Many chapters of the book have been rewritten and describe major advances in internal medicine. Subjects that received only a paragraph or two of attention in previous editions are now covered in entire chapters. Among the chapters that have been extensively revised are the chapters on infections in the compromised host, on skin rashes in infections, on many of the viral infections, including cytomegalovirus and Epstein-Barr virus, on sexually transmitted diseases, on diabetes mellitus, on disorders of bone and mineral metabolism, and on lymphadenopathy and splenomegaly. The major revisions in these chapters and many

Harrison's Principles of Internal Medicine

Fluorine substituents have become a widespread and important drug component, their introduction facilitated by the development of safe and selective fluorinating agents. Organofluorine affects nearly all physical and adsorption, distribution, metabolism, and excretion properties of a lead compound. Its inductive effects are relatively well understood, enhancing bioavailability, for example, by reducing the basicity of neighboring amines. In contrast, exploration of the specific influence of carbon-fluorine single bonds on docking interactions, whether through direct contact with the protein or through stereoelectronic effects on molecular conformation of the drug, has only recently begun. Here, we review experimental progress in this vein and add complementary analysis based on comprehensive searches in the Cambridge Structural Database and the Protein Data Bank.

Fluorine in Pharmaceuticals: Looking Beyond Intuition.

Curcumin, a polyphenolic compound derived from dietary spice turmeric, possesses diverse pharmacologic effects including anti-inflammatory, antioxidant, antiproliferative and antiangiogenic activities. Phase I clinical trials have shown that curcumin is safe even at high doses (12 g/day) in humans but exhibit poor bioavailability. Major reasons contributing to the low plasma and tissue levels of curcumin appear to be due to poor absorption, rapid metabolism, and rapid systemic elimination. To improve the bioavailability of curcumin, numerous approaches have been undertaken. These approaches involve, first, the use of adjuvant like piperine that interferes with glucuronidation; second, the use of liposomal curcumin; third, curcumin nanoparticles; fourth, the use of curcumin phospholipid complex; and fifth, the use of structural analogues of curcumin (e.g., EF-24). The latter has been reported to have a rapid absorption with a peak plasma half-life. Despite the lower bioavailability, therapeutic efficacy of...

Bioavailability of curcumin: problems and promises.

It has been reported recently by Kang and Yin that a complex O-cyclohexyl nitronate and the corresponding O-cyclohexyloxime constitute the “first completely stable axial conformers of monosubstituted cyclohexanes at room temperature.” If true, this claim violates a central principle of alicyclic conformational analysis. We have evaluated it by performing ab initio and molecular mechanics calculations to show that energy barriers in the C−O−XC−C(O)−O−C system (X = N and N+−O-) are low and that the equatorial−axial ratio is 2−3:1. To experimentally verify the predictions, we have synthesized seven analogues of the previously reported O-cyclohexyl nitronate using Mitsunobu chemistry, including genuine O-axial and O-equatorial conformers anchored by a 4-tert-butyl group. Both the 1H and 13C NMR spectra of the compounds have been carefully analyzed to be in complete accord with literature precedent. Finally, we have also prepared the compound claimed to be monosubstituted and O-axial. NMR analysis shows the O-...

On "pure axial" monosubstituted cyclohexanes: Cyclohexyl nitronate esters adopt O-equatorial conformations

Protonated 3-Fluoropiperidines: An Unusual Fluoro Directing Effect and a Test for Quantitative Theories of Solvation.

Monocyclic Enediyne Collapse to 1,4-Diyl Biradicals: A Pathway Under Strain Control.

We have discovered a novel and highly diastereoselective synthesis of azetinyl thiazolidine-2-thiones that utilizes additions of the chlorotitanium enolates of N-acyl thiazolidin-2-thiones to O-methyl aldoximes. The “anti” azetines can be subsequently converted to the corresponding α,β-disubstituted β-amino carbonyl compound with retention of stereochemistry. The formation of azetine and the product of its “hydrolytic” opening has been confirmed by X-ray crystallographic analyses.

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Diastereoselective Addition of Chlorotitanium Enolate of N-Acyl Thiazolidinethione to O-Methyl Oximes: A Novel, Stereoselective Synthesis of α,β-Disubstituted β-Amino Carbonyl Compounds via Chiral Auxiliary Mediated Azetine Formation.

James P. Snyder

Papers

On "pure axial" monosubstituted cyclohexanes: Cyclohexyl nitronate esters adopt O-equatorial conformations

Protonated 3-Fluoropiperidines: An Unusual Fluoro Directing Effect and a Test for Quantitative Theories of Solvation.

Monocyclic Enediyne Collapse to 1,4-Diyl Biradicals: A Pathway Under Strain Control.

Diastereoselective Addition of Chlorotitanium Enolate of N-Acyl Thiazolidinethione to O-Methyl Oximes: A Novel, Stereoselective Synthesis of α,β-Disubstituted β-Amino Carbonyl Compounds via Chiral Auxiliary Mediated Azetine Formation.

Infrared Spectroscopic Characterization of Cyanocuprates J. Am. Chem. Soc. 1996, 118, 8808−8816