Design, synthesis, and biological evaluation of 8-biarylquinolines: a novel class of PDE4 inhibitors

The structure-activity relationship of a novel series of 8-biarylquinolines acting as type 4 phosphodiesterase (PDE4) inhibitors is described herein. Prototypical compounds from this series are potent and non-selective inhibitors of the four distinct PDE4 (IC(50)<10 nM) isozymes (A-D). In a human whole blood in vitro assay, they inhibit (IC(50)<0.5 microM) the LPS-induced release of the cytokine TNF-alpha. Optimized inhibitors were evaluated in vivo for efficacy in an ovalbumin-induced bronchoconstriction model in conscious guinea pigs. Their propensity to produce an emetic response was evaluated by performing pharmacokinetic studies in squirrel monkeys. This work has led to the identification of several compounds with excellent in vitro and in vivo profiles, including a good therapeutic window of efficacy over emesis.     

Design, synthesis and antitumor evaluation of novel thalidomide dithiocarbamate and dithioate analogs against Ehrlich ascites carcinoma-induced solid tumor in Swiss albino mice

A series of 16 novel thalidomide sulfur analogs containing one and two sulfur atoms 2 and 4-18, respectively, were designed and synthesized. These compounds were screened for in vitro antitumor activity against Ehrlich ascites carcinoma (EAC) cell line and exhibited potent cytotoxic activity. On the bases of the obtained results for in vitro cytotoxic activity, thalidomide sulfur analogs containing two sulfur atoms 8, 9, 13 and 14 were selected and tested in vivo against EAC-induced solid tumor in female mice compared to thalidomide 1 as well as its analog 2 and exhibited a highly significant reduction in tumor volume (TV). Results illustrated the antioxidative activity of these compounds as the level of hepatic lipid peroxidation decreased and levels of antioxidant enzymes like superoxide dismutase (SOD) and catalase were elevated. The histopathological investigations revealed that thalidomide sulfur analogs 2, 8, 9, 13 and 14 have antimitotic, apoptotic and necrotic activities against solid tumor. These compounds lead to increase of Fas-L expression. The immunohistochemical studies showed a decrease in Ki67 and vascular endothelial growth factor (VEGF) staining in tumor cells from treated-animals when compared with non-treated groups, which suggests an inhibition of tumor proliferation rate and angiogenic process associated with tumor growth. Compounds 9 and 13 were the most potent compounds in tumor necrosis without liver necrosis. At the same time, treatment with compound 9 resulted in liver degeneration.     

Influence of exogenous enzymes on nutrient digestibility, extent of ruminal fermentation as well as milk production and composition in dairy cows

This experiment studied effects of a mixture of exogenous enzymes (ZADO^®) from anaerobic bacteria on ruminal fermentation, feed intake, digestibility, as well as milk production and composition in cows fed total mixed rations (TMRs; 0.7 corn silage and 0.3 of a concentrate mixture). Twenty lactating multiparous Brown Swiss cows (500 ± 12.4 kg live weight) were randomly assigned into two experimental groups of 10 immediately after calving and fed a TMR with or without (CTRL) addition of 40 g/cow/d of enzymes for 12 weeks. Addition of enzymes increased (P<0.05) rumen microbial N synthesis. Intake of dry matter (DM) and organic matter (OM) was positively influenced (P<0.05) by supplementation, and digestibility of all nutrients was higher (P<0.05) in the total tract of supplemented cows, although the magnitude of the improvement varied among nutrients, with the highest improvement in aNDFom and ADFom (418–584 and 401–532 g/kg respectively; P<0.05) than the other nutrients. Supplementation of enzymes also increased (P<0.05) rumen ammonia N and total short chain fatty acid (SCFA) concentrations, and individual SCFA proportions were also altered with an increase in acetate (61.0–64.8 mol/100 mol; P=0.05) before feeding, and acetate and propionate increased 3 h post-feeding (60.0–64.0 and 18.3–20.8 mol/100 mol respectively; P<0.05). Milk and milk protein production was higher (12.8–15.7 and 0.45–0.57 kg/d respectively; P<0.05) for cows fed the ZADO^® supplemented diet. This exogenous enzyme product, supplemented daily to the TMR of cows in early lactation, increased milk production due to positive effects on nutrient intake and digestibility, extent of ruminal fermentation and microbial protein synthesis.     

Delayed fluorescence as a universal tool for the measurement of circadian rhythms in higher plants

The plant circadian clock plays an important role in enhancing performance and increasing vegetative yield. Much of our current understanding of the mechanism and function of the plant clock has come from the development of Arabidopsis thaliana as a model circadian organism. Key to this rapid progress has been the development of robust circadian markers, specifically circadian-regulated luciferase reporter genes. Studies of the clock in crop species and non-model organisms are currently hindered by the absence of a simple high-throughput universal assay for clock function, accuracy and robustness. Delayed fluorescence (DF) is a fundamental process occurring in all photosynthetic organisms. It is luminescence-produced post-illumination due to charge recombination in photosystem II (PSII) leading to excitation of P680 and the subsequent emission of a photon. Here we report that the amount of DF oscillates with an approximately 24-h period and is under the control of the circadian clock in a diverse selection of plants. Thus, DF provides a simple clock output that may allow the clock to be assayed in vivo in any photosynthetic organism. Furthermore, our data provide direct evidence that the nucleus-encoded, three-loop circadian oscillator underlies rhythms of PSII activity in the chloroplast. This simple, high-throughput and non-transgenic assay could be integrated into crop breeding programmes, the assay allows the selection of plants that have robust and accurate clocks, and possibly enhanced performance and vegetative yield. This assay could also be used to characterize rapidly the role and function of any novel Arabidopsis circadian mutant.     

Towards calixarene-based prodrugs: Drug release and antibacterial behaviour of a water-soluble nalidixic acid/calix[4]arene ester adduct

A water-soluble calixarene-based heterocyclic podand incorporating a quinolone antibiotic subunit, the nalidixic acid, was synthesised and fully characterised. Its prodrug behaviour was assessed in vitro by HPLC, demonstrating the release of the tethered quinolone in model biological conditions. Microbiological studies performed on various Gram-positive and Gram-negative reference strains showed very interesting antibacterial activities.     

Exploring Hypotheses of the Actions of TGF-β1 in Epidermal Wound Healing Using a 3D Computational Multiscale Model of the Human Epidermis

In vivo and in vitro studies give a paradoxical picture of the actions of the key regulatory factor TGF-β1 in epidermal wound healing with it stimulating migration of keratinocytes but also inhibiting their proliferation. To try to reconcile these into an easily visualized 3D model of wound healing amenable for experimentation by cell biologists, a multiscale model of the formation of a 3D skin epithelium was established with TGF-β1 literature–derived rule sets and equations embedded within it. At the cellular level, an agent-based bottom-up model that focuses on individual interacting units (keratinocytes) was used. This was based on literature-derived rules governing keratinocyte behavior and keratinocyte/ECM interactions. The selection of these rule sets is described in detail in this paper. The agent-based model was then linked with a subcellular model of TGF-β1 production and its action on keratinocytes simulated with a complex pathway simulator. This multiscale model can be run at a cellular level only or at a combined cellular/subcellular level. It was then initially challenged (by wounding) to investigate the behavior of keratinocytes in wound healing at the cellular level. To investigate the possible actions of TGF-β1, several hypotheses were then explored by deliberately manipulating some of these rule sets at subcellular levels. This exercise readily eliminated some hypotheses and identified a sequence of spatial-temporal actions of TGF-β1 for normal successful wound healing in an easy-to-follow 3D model. We suggest this multiscale model offers a valuable, easy-to-visualize aid to our understanding of the actions of this key regulator in wound healing, and provides a model that can now be used to explore pathologies of wound healing.     

Effect of dietary sesame oil as antioxidant on brain hippocampus of rat in focal cerebral ischemia

Oxidative stress may be regarded as an imbalance between free radical production and opposing antioxidant defenses. Free radical oxidative stress is implicated in rat cerebral ischemia and naturaceutical antioxidants are dietary supplements that have been reported to have neuroprotective activity. Many studies have reported dietary sesame oil (SO) as an effective antioxidant. In the present study the neuroprotective effect of dietary SO was evaluated against middle cerebral artery occlusion (MCAO)-induced cerebral ischemia injury in rats. Rats were fed on diet (20% SO) for 15 days. The middle cerebral artery of adult male Wistar rat was occluded for 2 h and reperfused for 22 h. The antioxidant properties of brain were measured as levels of reduced glutathione (GSH), glutathione-S-transferase (GST), glutathione peroxide (GPx), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD) and thiobarbituric acid reactive substance (TBARS). A decrease in the activity of all the enzymatic and non-enzymatic antioxidants was observed along with an increase in lipid peroxidation (LPO) in MCAO group. The neurobehavioral activity of rats was also observed by using videopath analyzer. Dietary SO improved the antioxidant status in MCAO+SO group when compared with MCAO group. The results of neurobehavioral activity also support our biochemical data. The results obtained suggest protective effect of SO against cerebral ischemia in rat brain through their antioxidant properties.     

Preferential inhibition of human phosphodiesterase 4 by ibudilast

Ibudilast ophthalmic solution exhibited an improved clinical efficacy over cromoglycate in the treatment of allergic conjunctivitis. To further characterize its principal mode of action, the phosphodiesterase (PDE) inhibitory profile of ibudilast has been examined using human recombinant enzymes. Ibudilast, but not the other commonly used anti-allergic ophthalmic solutions including cromoglycate, ketotifen, tranilast and levocabastine, potently inhibits purified human PDE4A, 4B, 4C and 4D with IC50 values at 54, 65, 239 and 166 nM, respectively. Ibudilast effectively blocks lipopolysaccharide (LPS)-induced tumor necrosis factor (TNFalpha, IC50 = 6.2 microM) and N-formyl-Met-Leu-Phe (fMLP)-induced leukotriene (LT) B4 biosynthesis (IC50 = 2.5 microM) in human whole blood, which are 3 and 6-fold more potent than cilomilast, respectively. The attenuated inflammatory and allergic responses from the potent and preferential PDE4 inhibition of ibudilast may have contributed significantly to its beneficial pharmacological responses and distinguishes ibudilast from the other ophthalmic solutions in the treatment of ocular allergy.