Discovery of 3-acetyl-4-hydroxy-2-pyranone derivatives and their difluoridoborate complexes as a novel class of HIV-1 integrase inhibitors

HIV-1 integrase (IN) has emerged as an important therapeutic target for anti-HIV drug development. Its uniqueness to the virus and its critical role in the viral life cycle makes IN suitable for selective inhibition. The recent approval of Raltegravir (MK-0518) has created a surge in interest and great optimism in the field. In our ongoing IN drug design research, we herein report the discovery of substituted analogs of 3-acetyl-4-hydroxy-2-pyranones and their difluoridoborate complexes as novel IN inhibitors. In many of these compounds, complexation with boron difluoride increased the potency and selectivity of IN inhibition. Compound 9 was most active with an IC(50) value of 9 microM and 3 microM for 3'-processing and strand transfer inhibition, respectively.     

The influence of artery wall curvature on the anatomical assessment of stenosis severity derived from fractional flow reserve: a computational fluid dynamics study

This study aims to investigate the influence of artery wall curvature on the anatomical assessment of stenosis severity and to identify a region of misinterpretation in the assessment of per cent area stenosis (AS) for functionally significant stenosis using fractional flow reserve (FFR) as standard. Five artery models of different per cent AS severity (70, 75, 80, 85 and 90%) were considered. For each per cent AS severity, the angle of curvature of the arterial wall varied from straight to an increasingly curved model (0°, 30°, 60°, 90° and 120°). Computational fluid dynamics was performed under transient physiologic hyperemic flow conditions to investigate the influence of artery wall curvature on the pressure drop and the FFR. The findings in this study may be useful in in vitro anatomical assessment of functionally significant stenosis. The FFR decreased with increasing stenosis severity for a given curvature of the artery wall. Moreover, a significant decrease in FFR was found between straight and curved models discussed for a given severity condition. These findings indicate that the curvature effect was included in the FFR assessment in contrast to minimum lumen area (MLA) or per cent AS assessment. The MLA or per cent AS assessment may lead to underestimation of stenosis severity. From this numerical study, an uncertainty region could be evaluated using the clinical FFR cutoff value of 0.8. This value was observed at 81.98 and 79.10% AS for arteries with curvature angles of 0° and 120° respectively. In conclusion, the curvature of the artery should not be neglected in in vitro anatomical assessment.     

Picomonas judraskeda Gen. Et Sp. Nov.: The First Identified Member of the Picozoa Phylum Nov., a Widespread Group of Picoeukaryotes,Formerly Known as ‘Picobiliphytes’

In 2007, a novel, putatively photosynthetic picoeukaryotic lineage, the ‘picobiliphytes’, with no known close eukaryotic relatives, was reported from 18S environmental clone library sequences and fluorescence in situ hybridization. Although single cell genomics later showed these organisms to be heterotrophic rather than photosynthetic, until now this apparently widespread group of pico-(or nano-)eukaryotes has remained uncultured and the organisms could not be formally recognized. Here, we describe Picomonas judraskeda gen. et sp. nov., from marine coastal surface waters, which has a ‘picobiliphyte’ 18S rDNA signature. Using vital mitochondrial staining and cell sorting by flow cytometry, a single cell-derived culture was established. The cells are biflagellate, 2.5–3.8×2–2.5 µm in size, lack plastids and display a novel stereotypic cycle of cell motility (described as the “jump, drag, and skedaddle”-cycle). They consist of two hemispherical parts separated by a deep cleft, an anterior part that contains all major cell organelles including the flagellar apparatus, and a posterior part housing vacuoles/vesicles and the feeding apparatus, both parts separated by a large vacuolar cisterna. From serial section analyses of cells, fixed at putative stages of the feeding cycle, it is concluded that cells are not bacterivorous, but feed on small marine colloids of less than 150 nm diameter by fluid-phase, bulk flow endocytosis. Based on the novel features of cell motility, ultrastructure and feeding, and their isolated phylogenetic position, we establish a new phylum, Picozoa, for Picomonas judraskeda, representing an apparently widespread and ecologically important group of heterotrophic picoeukaryotes, formerly known as ‘picobiliphytes’.     

Impact of Zoo Visitors on the Fecal Cortisol Levels and Behavior of an Endangered Species: Indian Blackbuck (Antelope cervicapra L.)

This study investigated behavioral activities (resting, moving, aggressive, social, and reproductive behavior) and fecal cortisol levels in 8 individually identified adult male blackbucks during periods of varying levels of zoo visitors (zero, low, high, and extremely high zoo visitor density). This study also elucidated whether zoo visitor density could disturb nonhuman animal welfare. This study analyzed fecal cortisol from the samples of blackbuck by radioimmunoassay and found significant differences (p < .05) for time the animals devoted to moving, resting, aggressive, reproductive, and social behavior on days with high and extremely high levels of zoo visitors. The ANOVA with Duncan's Multiple Range Test test showed that the fecal cortisol concentration was higher (p < .05) during the extremely high (137.30 ± 5.88 ng/g dry feces) and high (113.51 ± 3.70 ng/g dry feces) levels of zoo visitor density. The results of the study suggest that zoo visitor density affected behavior and adrenocortical secretion in Indian Blackbuck, and this may indicate an animal welfare problem.     

Evaluation of functional severity of coronary artery disease and fluid dynamics' influence on hemodynamic parameters: A review

Coronary Artery Disease (CAD) is responsible for most of the deaths in patients with cardiovascular diseases. Diagnostic coronary angiography analysis offers an anatomical knowledge of the severity of the stenosis. The functional or physiological significance is more valuable than the anatomical significance of CAD. Clinicians assess the functional severity of the stenosis by resorting to an invasive measurement of the pressure drop and flow. Hemodynamic parameters, such as pressure wire assessment fractional flow reserve (FFR) or Doppler wire assessment coronary flow reserve (CFR) are well-proven techniques to evaluate the physiological significance of the coronary artery stenosis in the cardiac catheterization laboratory. Between the two techniques mentioned above, the FFR is seen as a very useful index. The presence of guide wire reduces the coronary flow which causes the underestimation of pressure drop across the stenosis which leads to dilemma for the clinicians in the assessment of moderate stenosis. In such condition, the fundamental fluid mechanics is useful in the development of new functional severity parameters such as pressure drop coefficient and lesion flow coefficient. Since the flow takes place in a narrowed artery, the blood behaves as a non-Newtonian fluid. Computational fluid dynamics (CFD) allows a complete coronary flow simulation to study the relationship between the pressure and flow. This paper aims at explaining (i) diagnostic modalities for the evaluation of the CAD and valuable insights regarding FFR in the evaluation of the functional severity of the CAD (ii) the role of fluid dynamics in measuring the severity of CAD.     

Design,synthesis and in vitro microbiological evaluation of 6,6-dimethyl-7,9-diaryl-1,2,4,8-tetraazaspiro[4.5]decan-3-thiones - A new series of ‘tailor-made’ compounds

Some novel ‘tailor-made’ compounds, 6,6-dimethyl-7,9-diaryl-1,2,4,8-tetraazaspiro[4.5]decan-3-thiones 23–27 have been studied for their in vitro antibacterial activity against Staphylococcus aureus, β-Heamolytic streptococcus, Vibreo cholerae, Salmonella typhii, Shigella felxneri, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa and anti-fungal activity against Aspergillus flavus, Mucor, Rhizopus and Microsporum gypsuem. Compounds 24 and 25 exerted potent antibacterial activity against S. aureus, β-H. streptococcus, E. coli and P. aeruginosa whereas all compounds 23–27 exerted strong in vitro antifungal activity against A. flavus, Mucor and Rhizopus.     

A Glycosaminoglycan Based,Modular Tissue Scaffold System for Rapid Assembly of Perfusable,High Cell Density,Engineered Tissues

The limited ability to vascularize and perfuse thick, cell-laden tissue constructs has hindered efforts to engineer complex tissues and organs, including liver, heart and kidney. The emerging field of modular tissue engineering aims to address this limitation by fabricating constructs from the bottom up, with the objective of recreating native tissue architecture and promoting extensive vascularization. In this paper, we report the elements of a simple yet efficient method for fabricating vascularized tissue constructs by fusing biodegradable microcapsules with tunable interior environments. Parenchymal cells of various types, (i.e. trophoblasts, vascular smooth muscle cells, hepatocytes) were suspended in glycosaminoglycan (GAG) solutions (4%/1.5% chondroitin sulfate/carboxymethyl cellulose, or 1.5 wt% hyaluronan) and encapsulated by forming chitosan-GAG polyelectrolyte complex membranes around droplets of the cell suspension. The interior capsule environment could be further tuned by blending collagen with or suspending microcarriers in the GAG solution These capsule modules were seeded externally with vascular endothelial cells (VEC), and subsequently fused into tissue constructs possessing VEC-lined, inter-capsule channels. The microcapsules supported high density growth achieving clinically significant cell densities. Fusion of the endothelialized, capsules generated three dimensional constructs with an embedded network of interconnected channels that enabled long-term perfusion culture of the construct. A prototype, engineered liver tissue, formed by fusion of hepatocyte-containing capsules exhibited urea synthesis rates and albumin synthesis rates comparable to standard collagen sandwich hepatocyte cultures. The capsule based, modular approach described here has the potential to allow rapid assembly of tissue constructs with clinically significant cell densities, uniform cell distribution, and endothelialized, perfusable channels.     

Inhibition of breast cancer xenografts in a mouse model and the induction of apoptosis in multiple breast cancer cell lines by lactoferricin B peptide

Breast cancer has a diverse aetiology characterized by the heterogeneous expression of hormone receptors and signalling molecules, resulting in varied sensitivity to chemotherapy. The adverse side effects of chemotherapy coupled with the development of drug resistance have prompted the exploration of natural products to combat cancer. Lactoferricin B (LfcinB) is a natural peptide derived from bovine lactoferrin that exhibits anticancer properties. LfcinB was evaluated in vitro for its inhibitory effects on cell lines representing different categories of breast cancer and in vivo for its suppressive effects on tumour xenografts in NOD-SCID mice. The different breast cancer cell lines exhibited varied levels of sensitivity to apoptosis induced by LfcinB in the order of SKBR3>MDA-MB-231>MDA-MB-468>MCF7, while the normal breast epithelial cells MCF-10A were not sensitive to LfcinB. The peptide also inhibited the invasion of the MDA-MB-231 and MDA-MB-468 cell lines. In the mouse xenograft model, intratumoural injections of LfcinB significantly reduced tumour growth rate and tumour size, as depicted by live imaging of the mice using in vivo imaging systems (IVIS). Harvested tumour volume and weight were significantly reduced by LfcinB treatment. LfcinB, therefore, is a promising and safe candidate that can be considered for the treatment of breast cancer.     

Direct differentiation of human embryonic stem cells to hepatocyte-like cells exhibiting functional activities

The utilization of human hepatocytes for biomedical research, drug discovery, and treatment of liver diseases is hindered by the limited availability of donated livers and the variability of their derived hepatocytes. Human embryonic stem cells (hESCs) are pluripotent and provide a unique, unlimited resource for human hepatocytes. However, differentiation of hESCs to hepatocytes remains a challenge. We have developed a multistage procedure by which hESCs can be directly differentiated to hepatocyte-like cells without embryoid body formation and the requirement of sodium butyrate. The hESC-derived hepatocyte-like cells (HLCs) exhibited characteristic hepatocyte morphology, expressed hepatocyte markers, including alpha-fetoprotein, albumin, and hepatocyte nuclear factor 4alpha, and possessed hepatocyte-specific activities, such as p450 metabolism, albumin production, glycogen storage, and uptake and excretion of indocyanine green. Hepatocyte growth factor was found to play a positive role in promoting hepatocyte differentiation. Our differentiation system has shown that hESCs can be differentiated to hepatocyte-like cells capable of executing a range of hepatocyte functions. Therefore, it presents a proof-of-principle of potential applications of using the hESC-derived hepatocytes. Additionally, the hESC-derived HLCs provide a unique model to study the mechanisms involved in human hepatocyte differentiation and liver function.