A Review on the New and Old Anticoagulants.

Anticoagulants serve as the primary strategy for the prevention and treatment of both arterial and venous thromboembolism. Anticoagulants disrupt coagulation by interfering at various points in the coagulation cascade. This class of medications does not lyse clots that already exist; rather, it prevents thrombus formation and prevents or slows the extension of an existing clot. For decades, the standard therapy for patients requiring oral anticoagulation was warfarin. However, due to some of the shortcomings of warfarin, including the need for continuous routine monitoring, longtime onset and offset of anticoagulation effect, major food and drug interactions, and high incidence of bleeding, newer agents, termed direct oral anticoagulants, or DOACs were developed. This article will provide a review of clinically important information regarding the most commonly used anticoagulants and their reversal agents.

The Effects of Class-Specific Histone Deacetylase Inhibitors on the Development of Limbs During Organogenesis.

Histone deacetylases (HDACs) play a major role in chromatin remodeling, gene regulation, and cellular signaling. While the role of each class of HDAC during normal development is unclear, several HDAC inhibitors are embryotoxic; the mechanisms leading to the teratogenicity of HDAC inhibitors are not known. Here, we investigated the effects of class-specific HDAC inhibitors on the development of organogenesis-stage murine limbs. Timed-pregnant COL2A1-ECFP, COL10A1-mCherry, and COL1A1-YFP CD1 reporter mice were euthanized on gestation day 12; embryonic forelimbs were excised and cultured in vitro for 1, 3, and 6 days in the presence or absence of MS275 (a class I HDAC inhibitor), MC1568 (a class III HDAC inhibitor), Sirtinol (a class II HDAC inhibitor), or valproic acid, our positive control. Fluorescently tagged COL2A1, COL10A1, and COL1A1 served as markers of the differentiation of proliferative chondrocytes, hypertrophic chondrocytes, and osteoblasts, respectively. MS275 and valproic acid caused a reduction in expression of all three markers, suggesting effects on both chondrogenesis and osteogenesis. MC1568 had no effect on chondrocyte markers and mildly inhibited COL1A1 expression at 6 days. Sirtinol had no effect on COL2A1 expression or chondrocyte differentiation 1 day following exposure; however, it caused a drastic regression in limb cartilage and reduced the expression of all three differentiation markers to nearly undetectable levels at 6 days. MS275 and Sirtinol caused a 2.2- and 2.7-fold increase, respectively, in cleaved-caspase 3, a marker of apoptosis, suggesting embryotoxicity. These data demonstrate that inhibition of class I or III HDACs causes severe developmental toxicity and is highly teratogenic.

The changing face of oral anticoagulants.

Warfarin has been the established oral anticoagulant for the last 50 years, being effective in the prevention and treatment of venous and arterial thromboembolic disorders. However, the frequent requirement for INR monitoring, multiple drug and food interactions have fuelled the need for development of new oral anticoagulants. Dabigatran is the first of a series of new oral anticoagulants that are emerging as the successors to warfarin. This new group of anticoagulants is rapidly gaining FDA and NICE approval and has proven non-inferiority to warfarin and viable alternatives to warfarin in the coming years. Given the obvious impact of this on dental treatment in the primary care and hospital setting this article aims to increase familiarisation with this new medicine group.

Anti-cancer activity of a novel small molecule compound that simultaneously activates p53 and inhibits NF-κB signaling.

The p53 and NF-κB pathways play important roles in diverse cellular functions, including cell growth, apoptosis, and tumorigenesis. Mutations that inactivate the p53 gene and constitutive NF-κB pathway activation are common occurrences in human cancers. Although many drugs are being developed that selectively activate p53 or inhibit NF-κB, there are few drug candidates that can do both. Simultaneous activation of p53 and inhibition of the NF-κB pathway is therefore a prime target for new cancer drug development. This study is the first report of a high-throughput approach with mass compounds that concurrently target both pathways. Using a cell-based screening assay and a library of 200,000 synthetic compounds, we identified 9 small molecules that simultaneously inhibit NF-κB and activate p53. One of these compounds, N-2, increased the expression of p53 target genes, including p21 and GADD45a. In addition, N-2 inhibited the transcriptional activity of NF-κB, concomitantly repressing interleukin-6 and monocyte chemotactic protein-1 (MCP-1) expression. When cell lines derived from a diverse range of cancers were treated in vitro with N-2, we observed increased cell death. N-2 also significantly inhibited allograft growth in murine models of melanoma and lung carcinoma. Our findings suggest that N-2 may act as a bivalent anti-cancer agent through simultaneous modulation of NF-κB and p53 activities.

Bp44mT: an orally active iron chelator of the thiosemicarbazone class with potent anti-tumour efficacy.

BACKGROUND AND PURPOSE: Our previous studies demonstrated that a thiosemicarbazone iron chelator (di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone; Dp44mT) possesses potent and selective anti-cancer activity but led to cardiotoxicity at non-optimal doses. In this study, we examined the in vivo anti-tumour efficacy and tolerability of a new-generation 2-benzoylpyridine thiosemicarbazone iron chelator (2-benzoylpyridine-4,4-dimethyl-3-thiosemicarbazone; Bp44mT) administered via the oral or i.v. routes. EXPERIMENTAL APPROACH: BpT chelators were tested in vitro against human lung cancer cells (DMS-53) and in vivo in DMS-53 tumour xenografts in mice. The toxicity of Bp44mT in vivo and its effects on the expression of iron-regulated molecules involved in growth and cell cycle control were investigated. KEY RESULTS: Administration of Bp44mT by either route resulted in marked dose-dependent inhibition of tumour growth. When administered at 50 mg·kg(-1) via oral gavage three times per week for 23 days, the net xenograft growth was inhibited by 75%, compared with vehicle-treated mice. Toxicological examination showed reversible alterations including slight reduction of RBC count, with a decrease of liver and splenic iron levels, which confirmed iron chelation in vivo. Importantly, in contrast to Dp44mT, the chelator-treated mice did not show cardiac histological abnormalities. There was also no significant weight loss in mice, suggesting oral administration of Bp44mT was well tolerated. CONCLUSIONS AND IMPLICATIONS: This is the first study to show that Bp44mT can be given orally with potent anti-tumour efficacy. Oral administration of a novel and effective chemotherapeutic agent provides the benefits of convenience for chronic dosing regimens.

The specific slow afterhyperpolarization inhibitor UCL2077 is a subtype-selective blocker of the epilepsy associated KCNQ channels.

Mutations in members of the KCNQ channel family underlie multiple diseases affecting the nervous and cardiovascular systems. Despite their clinical relevance, research into these channels is limited by the lack of subtype-selective inhibitors, making it difficult to differentiate the physiological function of each family member in vivo. We have proposed that KCNQ channels might partially underlie the calcium-activated slow afterhyperpolarization (sAHP), a neuronal conductance whose molecular components are uncertain. Here, we investigated whether 3-(triphenylmethylaminomethyl)pyridine (UCL2077), identified previously as an inhibitor of the sAHP in neurons, acts on members of the KCNQ family expressed in heterologous cells. We found that 3 µM UCL2077 strongly inhibits KCNQ1 and KCNQ2 channels and weakly blocks KCNQ4 channels in a voltage-independent manner. In contrast, UCL2077 potentiates KCNQ5 channels at more positive membrane potentials, with little effect at negative membrane potentials. We found that the effect of UCL2077 on KCNQ3 is bimodal: currents are enhanced at negative membrane potentials and inhibited at positive potentials. We found that UCL2077 facilitates KCNQ3 currents by inducing a leftward shift in the KCNQ3 voltage-dependence, a shift dependent on tryptophan 265. Finally, we show that UCL2077 has intermediate effects on KCNQ2/3 heteromeric channels compared with KCNQ2 and KCNQ3 homomers. Together, our data demonstrate that UCL2077 acts on KCNQ channels in a subtype-selective manner. This feature should make UCL2077 a useful tool for distinguishing KCNQ1 and KCNQ2 from less-sensitive KCNQ family members in neurons and cardiac cells in future studies.

Ag-modified Au nanocavity SERS substrates.

The engineering of cavity void metallic arrays allows to vary the plasmon-polariton mode energies from the near infrared to the ultraviolet through the tuning of the void height and diameter, and the selection of the appropriate material. Typically Au nanocavity substrates can be grown with better reproducibility, homogeneity, and stability, while Ag structures display significantly larger SERS enhancements. To exploit these two apparently excluding aspects, quality and enhancement, we report a detailed study of 500 nm Au-nanocavity templates modified by the controlled electrochemical deposition of 100 Ag layers, a thickness similar to the visible light skin-depth of bulk Ag. The SERS amplification of the ordered cavity-arrays is determined using 4-mercaptopyridine as a non-electronic resonant molecular probe. The ultrathin Ag layer modification of the Au substrates results in a strong amplification of the SERS signal both in the red and the green part of the spectrum, and in a spectral shift of the Raman resonance scans. These observations are assigned to Ag-induced changes in the plasmon-polariton response of the nanostructure. The reported results provide a general platform for the preparation of renewable SERS-active substrates that combine the durability and higher quality of Au nanotemplates, with the enhanced SERS amplification factors of Ag.

A novel class of cycloalkano[b]pyridines as potent and orally active opioid receptor-like 1 antagonists with minimal binding affinity to the hERG K+ channel.

A series of compounds based on 7-{[4-(2-methylphenyl)piperidin-1-yl]methyl}-6,7,8,9-tetrahydro-5 H-cyclohepta[ b]pyridine-9-ol ( (-)-8b), a potent and selective opioid receptor-like 1 (ORL1) antagonist, was prepared and evaluated using structure-activity relationship studies with the aim of removing its affinity to human ether-a-go-go related gene (hERG) K (+) channel. From these studies, 10l was identified as an optimized structure with respect to ORL1 antagonist activity, and affinity to the hERG K (+)channel. Furthermore, 10l showed good in vivo antagonism with a wide therapeutic index in regards to adverse cardiovascular effects.

Defining the mechanism of activation of AMP-activated protein kinase by the small molecule A-769662, a member of the thienopyridone family.

AMP-activated protein kinase (AMPK) plays a key role in maintaining energy homeostasis. Activation of AMPK in peripheral tissues has been shown to alleviate the symptoms of metabolic diseases, such as type 2 diabetes, and consequently AMPK is a target for treatment of these diseases. Recently, a small molecule activator (A-769662) of AMPK was identified that had beneficial effects on metabolism in ob/ob mice. Here we show that A-769662 activates AMPK both allosterically and by inhibiting dephosphorylation of AMPK on Thr-172, similar to the effects of AMP. A-769662 activates AMPK harboring a mutation in the gamma subunit that abolishes activation by AMP. An AMPK complex lacking the glycogen binding domain of the beta subunit abolishes the allosteric effect of A-769662 but not the allosteric activation by AMP. Moreover, mutation of serine 108 to alanine, an autophosphorylation site within the glycogen binding domain of the beta1 subunit, almost completely abolishes activation of AMPK by A-769662 in cells and in vitro, while only partially reducing activation by AMP. Based on our results we propose a model for activation of AMPK by A-769662. Importantly, this model may provide clues for understanding the mechanism by which AMP leads to activation of AMPK, which in turn may help in the identification of other AMPK activators.

Substituted 5-benzyl-2-phenyl-5H-imidazo[4,5-c]pyridines: a new class of pestivirus inhibitors.

A novel class of inhibitors of pestiviruses (5-substituted 2-phenyl-5H-imidazo[4,5-c]pyridines) is described. Modification of the substituent in position 5 resulted in analogues with high activity (EC(50)<100nM) and selectivity (SI>1000) against the pestivirus BVDV (bovine viral diarrhea virus).

PCTH: a novel orally active chelator for the treatment of iron overload disease.

Our laboratories have prepared a novel class of iron (Fe) chelators of the 2-pyridylcarboxaldehyde isonicotinoyl hydrazone (PCIH) class. This article will review the iron chelation efficacy of this series of chelators, both in cell culture and in animal models. Several PCIH analogs were shown to be effective at inducing iron mobilization and preventing iron uptake from the iron-transport protein, transferrin. Moreover, several of these ligands were effective at permeating the mitochondrion and inducing iron release. Studies in mice demonstrated that the PCIH analog, PCTH, was orally active and well tolerated by mice at doses ranging from 50 to 100 mg kg(-1), twice daily (b.d.). A dose-dependent increase in fecal 59Fe excretion was observed in the PCTH-treated group. This level of iron excretion was similar to that found for the orally effective chelators, pyridoxal isonicotinoyl hydrazone (PIH) and deferiprone (L1). The PCIH group of ligands clearly has the potential for the treatment of beta-thalassemia (thal) and Friedreich's Ataxia (FA).

A study of the potential of the pig as a model for the vaginal irritancy of benzalkonium chloride in comparison to the nonirritant microbicide PHI-443 and the spermicide vanadocene dithiocarbamate.

A porcine model was established to test the mucosal toxicity potential of a thiophene thiourea (PHI-443)-based anti-HIV microbicide and a vanadocene-based spermicide, vanadocene dithiocarbamate (VDDTC) in comparison to benzalkonium chloride (BZK). Nine domestic pigs (Duroc) in nonestrus stage received a single intravaginal application of 2% BZK, 2% PHI-443, or 0.1% VDDTC-containing gel. At various times after gel application, cell differentials and levels of inflammatory cytokines (IL-1beta, IL-4, IL-6, IL-8, IL-10, IL-18, IFN-gamma, and TNF-alpha) in cervicovaginal lavage (CVL) fluid were monitored by flow cytometry and ELISA, respectively. Eight pigs were exposed intravaginally to a gel with and without BZK or VDDTC for 4 consecutive days and vaginal tissues were scored histologically for inflammation using a new scoring system. Only CVL fluid from pigs exposed to BZK showed a significant increase of IL-1beta, IL-8, and also IL-18 production when compared to the controls, PHI-443 or VDDTC-treated groups. Maximum levels of BZK-induced IL-1beta (100-fold), IL-8 (2,500-fold), IL-18 (80-fold), and IFN-gamma (10-fold) were found at 24 hours. In the in vivo porcine vaginal irritation model, increased levels of vaginal IL-1beta, IL-8, and IL-18 were associated with histological changes consistent with vaginal inflammation. These results demonstrate that key cervicovaginal inflammatory cytokines are useful in vivo biomarkers for predicting the mucosal toxicity potential of vaginal products in the physiologically relevant and sensitive porcine model.

(1H-imidazo[4,5-c]pyridin-2-yl)-1,2,5-oxadiazol-3-ylamine derivatives: a novel class of potent MSK-1-inhibitors.

A novel series of imidazo[4,5-c]pyridines bearing a 1,2,5-oxadiazol-3-ylamine functionality has been developed. These are potent inhibitors of mitogen and stress-activated protein kinase-1.

Zolpidem: now classified as a psychotropic at risk of abuse.

Zolpidem is now listed on table IV of the Vienna Convention. Zopiclone has not yet been given the same classification.