Compound library development guided by protein structure similarity clustering and natural product structure

To identify biologically relevant and drug-like protein ligands for medicinal chemistry and chemical biology research the grouping of proteins according to evolutionary relationships and conservation of molecular recognition is an established method. We propose to employ structure similarity clustering of the ligand-sensing cores of protein domains (PSSC) in conjunction with natural product guided compound library development as a synergistic approach for the identification of biologically prevalidated ligands with high fidelity. This is supported by the concepts that (i) in nature spatial structure is more conserved than amino acid sequence, (ii) the number of fold types characteristic for all protein domains is limited, and (iii) the underlying frameworks of natural product classes with multiple biological activities provide evolutionarily selected starting points in structural space. On the basis of domain core similarity considerations and irrespective of sequence similarity, Cdc25A phosphatase, acetylcholinesterase, and 11beta-hydroxysteroid dehydrogenases type 1 and type 2 were grouped into a similarity cluster. A 147-member compound collection derived from the naturally occurring Cdc25A inhibitor dysidiolide yielded potent and selective inhibitors of the other members of the similarity cluster with a hit rate of 2-3%. Protein structure similarity clustering may provide an experimental opportunity to identify supersites in proteins.     

Treatment of recurrent attacks of supraventricular tachycardia during pregnancy causing complications in both mother and fetus

Cardiac arrhythmias including supraventricular tachycardia are commonly encountered during pregnancy. The case of a young Indian woman with recurrent attacks of supraventricular tachycardia during pregnancy which was managed with adenosine and verapamil is reported. The possible mechanisms of maternal and fetal complications are discussed.     

KLF2 is essential for primitive erythropoiesis and regulates the human and murine embryonic beta-like globin genes in vivo

The Krüppel-like factors (KLFs) are a family of C2/H2 zinc finger DNA-binding proteins that are important in controlling developmental programs. Erythroid Krüppel-like factor (EKLF or KLF1) positively regulates the beta-globin gene in definitive erythroid cells. KLF2 (LKLF) is closely related to EKLF and is expressed in erythroid cells. KLF2-/- mice die between embryonic day 12.5 (E12.5) and E14.5, because of severe intraembryonic hemorrhaging. They also display growth retardation and anemia. We investigated the expression of the beta-like globin genes in KLF2 knockout mice. Our results show that KLF2-/- mice have a significant reduction of murine embryonic Ey- and beta h1-globin but not zeta-globin gene expression in the E10.5 yolk sac, compared with wild-type mice. The expression of the adult beta(maj)- and beta(min)-globin genes is unaffected in the fetal livers of E12.5 embryos. In mice carrying the entire human globin locus, KLF2 also regulates the expression of the human embryonic epsilon-globin gene but not the adult beta-globin gene, suggesting that this developmental-stage-specific role is evolutionarily conserved. KLF2 also plays a role in the maturation and/or stability of erythroid cells in the yolk sac. KLF2-/- embryos have a significantly increased number of primitive erythroid cells undergoing apoptotic cell death.     

A Comparison of Outpatient Healthcare Expenditures Between Public and Private Medical Institutions in Urban China: An Instrumental Variable Approach

The growth of healthcare expenditure provokes constant comments and discussions, as countries battle the issues on cost containment and cost effectiveness. Prior to 1978, medical institutions in China were either state‐owned or were collective public hospitals. Since 1978, China has been trying to rebuild its healthcare system, which was destroyed during the ‘cultural revolution’, allowing private medical institutions to deliver healthcare services. As a result, private medical institutions have grown from 0% to 28.57% between 1978 and 2010. In this context, we compare outpatient healthcare expenditures between public and private medical institutions. The central problem of this comparison is that the choice of medical institution is endogenous. So we apply an instrumental variable (IV) framework utilizing geographic information (whether the closest medical institution is private) as the instrument while controlling for severity of health and other relevant confounding factors. Using China's Urban Resident Basic Medical Insurance Survey 2008–2010, we found that there is no difference in expenditure between public and private medical institutions when IV framework is used. Our econometric tests suggest that our IV model is specified appropriately. However, the ordinary least square model, which is inconsistent in the presence of endogenous regressor(s), reveals that public medical institutions are more expensive. Copyright © 2013 John Wiley & Sons, Ltd.     

The effects of selective cytokine inhibitory drugs (CC-10004 and CC-1088) on VEGF and IL-6 expression and apoptosis in myeloma and endothelial cell co-cultures

Myeloma cells and human umbilical vein endothelial cells (HUVECs) were co-cultured to model in vitro the interactions between myeloma and endothelium, and treated with thalidomide and two selective cytokine inhibitory drugs (SelCIDs, phosphodiesterase-4 inhibitors). Flow cytometry and enzyme-linked immunosorbent assay were used to assess production of two key cytokines--vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6)--and apoptosis in co-cultured HUVECs and myeloma cells. VEGF was produced by both myeloma cells and HUVECs, while IL-6 was almost exclusively produced by endothelial cells. In co-culture, there was significant up-regulation of VEGF and IL-6 production compared with the sum of separate myeloma and endothelial cell cultures. SelCIDs markedly inhibited production of both cytokines in co-cultures, with CC-10004 being more potent than CC-1088. In addition, SelCIDs induced myeloma cell apoptosis. Apoptosis in co-cultured myeloma cells was significantly lower than in those cultured separately, suggesting that co-culture partially protected myeloma cells from drug-induced apoptosis. This protective effect was probably due to IL-6 produced by endothelial cells in co-culture as addition of anti-IL-6 neutralizing antibody, but not anti-VEGF antibody, abrogated it. In conclusion, SelCIDs can exert their anti-myeloma activity through two mechanisms, i.e. inhibition of VEGF and IL-6 production by interacting myeloma and endothelium and induction of myeloma cell apoptosis.     

Diagnostic accuracy of dobutamine stress echocardiography for detection of coronary heart disease in hypertensive patients

To compare the diagnostic accuracy between dobutamme echocardiographyand treadmill exercise electrocardiography in detecting coronaryartery disease in hypertensive patients, 43 patients withoutelectrocardiographic evidence of left ventricular hypertrophyand basal ST-T changes, who had also undergone coronary angiography,were further evaluated by dobutamine echocardiography. The patientsalso underwent treadmill exercise echocardiography. Left ventricularmass index was calculated by echocardiography. Twenty-nine patientshad coronary artery disease, of whom 22 had multi-vessel diseaseand 14 a normal coronary anatomy. Twenty-eight patients hadan increased left ventricular mass index. The sensitivitiesof dobutaniine echocardiography and exercise electrocardiographyfor detecting coronary artery disease were 93% and 72% (P=0·08)respectively, and the specificities were 100% and 29%(P<0·005),respectively. Logistic regression analysis showed exercise electrocardiographyto be a poor predictor of coronary artery disease (P<0·09)but dobutamine echocardiography was significantly better (P<0·00l).When patients with increased left ventricular mass index wereexcluded, prediction of coronary anatomy by exercise electrocardiographyimproved only marginally (P=0·4) while dobutamine echocardiographywas significantly better (P<0·00l). Thus dobutamineechocardiography is superior to exercise electrocardiographyfor diagnosis of coronary artery disease in hypertensive patients.