Role of transporters in the disposition of a novel ß-lactamase inhibitor: relebactam (MK-7655).

OBJECTIVES: To identify the transporters involved in renal elimination of relebactam, and to assess the potential of relebactam as a perpetrator or victim of drug-drug interactions (DDIs) for major drug transporters. METHODS: A series of bidirectional transport, uptake and inhibition studies were conducted in vitro using transfected cell lines and membrane vesicles. The inhibitory effects of relebactam on major drug transporters, as well as the inhibitory effects of commonly used antibiotics/antifungals on organic anion transporter (OAT) 3-mediated uptake of relebactam, were assessed. RESULTS: Relebactam was shown to be a substrate of OAT3, OAT4, and multidrug and toxin extrusion (MATE) proteins MATE1 and MATE2K. Relebactam did not show profound inhibition across a panel of transporters, including organic anion-transporting polypeptides 1B1 and 1B3, OAT1, OAT3, organic cation transporter 2, MATE1, MATE2K, breast cancer resistance protein, multidrug resistance protein 1 and the bile salt export pump. Among the antibiotics/antifungals assessed for potential DDIs, probenecid demonstrated the most potent in vitro inhibition of relebactam uptake; however, such in vitro data did not translate into clinically relevant DDIs, suggesting that relebactam can be co-administered with OAT inhibitors, such as probenecid. CONCLUSIONS: Overall, relebactam has low potential to be a victim or perpetrator of DDIs with major drug transporters.

MK-8353: Discovery of an Orally Bioavailable Dual Mechanism ERK Inhibitor for Oncology.

The emergence and evolution of new immunological cancer therapies has sparked a rapidly growing interest in discovering novel pathways to treat cancer. Toward this aim, a novel series of pyrrolidine derivatives (compound 5) were identified as potent inhibitors of ERK1/2 with excellent kinase selectivity and dual mechanism of action but suffered from poor pharmacokinetics (PK). The challenge of PK was overcome by the discovery of a novel 3(S)-thiomethyl pyrrolidine analog 7. Lead optimization through focused structure-activity relationship led to the discovery of a clinical candidate MK-8353 suitable for twice daily oral dosing as a potential new cancer therapeutic.

The BACE1 inhibitor verubecestat (MK-8931) reduces CNS ß-amyloid in animal models and in Alzheimer's disease patients.

ß-Amyloid (Aß) peptides are thought to be critically involved in the etiology of Alzheimer's disease (AD). The aspartyl protease ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) is required for the production of Aß, and BACE1 inhibition is thus an attractive target for the treatment of AD. We show that verubecestat (MK-8931) is a potent, selective, structurally unique BACE1 inhibitor that reduced plasma, cerebrospinal fluid (CSF), and brain concentrations of Aß40, Aß42, and sAPPß (a direct product of BACE1 enzymatic activity) after acute and chronic administration to rats and monkeys. Chronic treatment of rats and monkeys with verubecestat achieved exposures >40-fold higher than those being tested in clinical trials in AD patients yet did not elicit many of the adverse effects previously attributed to BACE inhibition, such as reduced nerve myelination, neurodegeneration, altered glucose homeostasis, or hepatotoxicity. Fur hypopigmentation was observed in rabbits and mice but not in monkeys. Single and multiple doses were generally well tolerated and produced reductions in Aß40, Aß42, and sAPPß in the CSF of both healthy human subjects and AD patients. The human data were fit to an amyloid pathway model that provided insight into the Aß pools affected by BACE1 inhibition and guided the choice of doses for subsequent clinical trials.

Immunomodulatory effect of vancomycin on Treg in pediatric inflammatory bowel disease and primary sclerosing cholangitis.

Vancomycin has been shown to affect tumor necrosis factor-alpha (TNF-α) pathways as an immunomodulator; this is thought to be separate from its function as an antibiotic [1]. Previous studies have shown that oral vancomycin (OV) is an effective treatment for concomitant primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) in children [2, 3]. Since both diseases are associated with immune dysfunction, we hypothesized that vancomycin's therapeutic effect in IBD and PSC occurs through immunomodulation. Therefore, we examined the in vivo immunological changes that occur during OV treatment of 14 children with PSC and IBD. Within 3 months of OV administration, peripheral gamma-glutamyl transpeptidase (GGT) and alanine aminotransferase (ALT) concentrations, white blood cell (WBC) counts, and neutrophil counts normalized from elevated levels before treatment. Patients also demonstrated improved biliary imaging studies, liver biopsies and IBD symptoms and biopsies. Additionally, plasma transforming growth factor beta (TGF-ß) levels were increased without concurrent shifts in Th1-or Th2-associated cytokine production. Peripheral levels of CD4 + CD25hiCD127lo and CD4 + FoxP3+ regulatory T (Treg) cells also increased in OV-treated PSC + IBD patients compared to pretreatment levels. A unique case study shows that the therapeutic effects of OV in the treatment of PSC + IBD do not always endure after OV discontinuation, with relapse of PSC associated with a decrease in blood Treg levels; subsequent OV retreatment was then associated with a rise in blood Treg levels and normalization of liver function tests (LFTs). Taken together, these studies support immune-related pathophysiology of PSC with IBD, which is responsive to OV.

Pathways involved in the synergistic activation of macrophages by lipoteichoic acid and hemoglobin.

Lipoteichoic acid (LTA) is a Gram-positive cell surface molecule that is found in both a cell-bound form and cell-free form in the host during an infection. Hemoglobin (Hb) can synergize with LTA, a TLR2 ligand, to potently activate macrophage innate immune responses in a TLR2- and TLR4-dependent way. At low levels of LTA, the presence of Hb can result in a 200-fold increase in the secretion of IL-6 following macrophage activation. Six hours after activation, the macrophage genes that are most highly up-regulated by LTA plus Hb activation compared to LTA alone are cytokines, chemokines, receptors and interferon-regulated genes. Several of these genes exhibit a unique TLR4-dependent increase in mRNA levels that continued to rise more than eight hours after stimulation. This prolonged increase in mRNA levels could be the result of an extended period of NF-κB nuclear localization and the concurrent absence of the NF-κB inhibitor, IκBα, after stimulation with LTA plus Hb. Dynasore inhibition experiments indicate that an endocytosis-dependent pathway is required for the TLR4-dependent up-regulation of IL-6 secretion following activation with LTA plus Hb. In addition, interferon-ß mRNA is present after activation with LTA plus Hb, suggesting that the TRIF/TRAM-dependent pathway may be involved. Hb alone can elicit the TLR4-dependent secretion of TNF-α from macrophages, so it may be the TLR4 ligand. Hb also led to secretion of high mobility group box 1 protein (HMGB1), which synergized with LTA to increase secretion of IL-6. The activation of both the TLR2 and TLR4 pathways by LTA plus Hb leads to an enhanced innate immune response.

Using clinical data to capture nurse workload: implications for staffing and safety.

The purpose of this project was to demonstrate how a hospital clinical database can be utilized to calculate individual nursing unit activities that affect nurses' workload. While research has established that staffing is associated with patient safety, few studies have examined ways to measure nurse workload and its impact on patient safety. The widely used midnight census does not account for the number of patients who occupy a bed in a 24-hour period. In this study, a hospital clinical data repository was used to calculate workload measures such as total treated patients, midnight census, and admission, discharges, and transfers, as well as a unit activity index. Unit activity indexes for intensive care and medical-surgical units were compared over time, by shift, day of week, and month. Admission, discharges, and transfers varied according to unit type. During 1994 to 2006, unit activity index increased. Fluctuations in unit activity index were noted according to shift, day of week, and month. Hospital clinical data repositories can be used to calculate workload measures, and these measures should be incorporated with other traditional measures in making staffing decisions.

Improving the quality of rural nursing care.

The purpose of this chapter is to review the literature on quality of care in rural areas. Keywords related to rural quality of care were used to search CINAHL and MEDLINE databases for articles published between 2005 and 2007 (limited to studies occurring in the United States). The review consisted of a total of 46 articles. Limitations include inconsistent definitions of rural, the use of only articles available to the reviewers, an unclear understanding of the context of many of the studies, and lack of a clear operational definition of quality. The studies were grouped and discussed according to quality of workforce, practice, treatment, interventions, and technology in rural areas. Each study's contribution to the understanding of quality health care in rural areas and to determining what was effective in improving staff, patient, or organizational outcomes in rural areas was considered. This chapter also offers a discussion of ethical issues and data quality in rural research. Issues for future research include a focus on patient safety, mental health issues, and the use of technology to improve quality of care in rural areas. Future research should also focus on demonstration studies of model applications. The nursing profession has a unique opportunity to conduct research that will contribute to the development of knowledge that will ultimately improve the quality of health and health care for individuals in rural communities.

Lipoteichoic acid synergizes with glycosphingolipids to potently stimulate secretion of interleukin-6 from human blood cells.

In the present study, we found that lipoteichoic acid (LTA) synergizes with glycosphingolipids to stimulate human blood cells to secrete cytokines. We employed globoside, kerasin, and lactosylceramide as representative neutral glycosphingolipids and mixed gangliosides GM(2) and GM(3) as representative acidic glycosphingolipids. LTA and the glycosphingolipids enhanced cytokine secretion by human whole blood, peripheral blood mononuclear cells, and purified monocytes in a dose-dependent manner. The level of synergy ranged up to approximately 10-fold greater than the additive stimulation caused by LTA and glycosphingolipid alone. The greatest synergy was observed with GM(3). We also found that LTA synergizes with the synthetic bacterial lipopeptide mimic Pam3CysK4. In contrast, the glycosphingolipids suppressed the stimulation caused by Pam3CysK4. The stimulation of human cells requires the simultaneous presence of LTA and the glycosphingolipids and probably requires their physical interactions, as shown by dot blotting and nondenaturing polyacrylamide gel electrophoresis experiments. We hypothesize that the enhanced stimulation is due to heterooligomers that form between LTA and glycosphingolipids at the subcritical micelle concentrations used in these experiments. Previous studies showed that LTA also synergizes with hemoglobin. The data taken together suggest that LTA may be a pathogen-associated molecular pattern, although its full activity requires the presence of a synergistic partner(s).

Long-term treatment of primary sclerosing cholangitis in children with oral vancomycin: an immunomodulating antibiotic.

BACKGROUND: Primary sclerosing cholangitis is a rare chronic cholestatic condition of unknown etiology, frequently associated with inflammatory bowel disease and characterized by diffuse fibrosing and inflammatory destruction of the intra- and/or extrahepatic biliary duct system. PATIENTS AND METHODS: The study involved 14 children with primary sclerosing cholangitis confirmed by either liver biopsy, endoscopic retrograde cholangiopancreatography, and/or magnetic resonance cholangiogram. In each of the 14 cases, liver histology showed characteristic features consistent with primary sclerosing cholangitis. Eleven children had intrahepatic biliary beading and strictures (6 by endoscopic retrograde cholangiopancreatography; 5 by magnetic resonance cholangiogram). Biochemical tests of liver function including alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transpeptidase and the erythrocyte sedimentation rate were elevated for a mean 17 +/- 22 months before vancomycin treatment was initiated. All of the patients were shown to have inflammatory bowel disease histologically; 13 of those patients had clinical evidence of colitis. Oral vancomycin was given to all 14 patients. RESULTS: All 14 patients showed improvement in their alanine aminotransferase (P = 0.007), gamma-glutamyl transpeptidase (P = 0.005), erythrocyte sedimentation rate (P = 0.008), and clinical symptoms with oral vancomycin treatment. There was less improvement noted in the patients with cirrhosis when compared with the patients without cirrhosis. CONCLUSIONS: Before this study, there has not been an effective long-term treatment for sclerosing cholangitis to prevent the usual progression of this disease to cirrhosis. This study showed that oral vancomycin could be an effective long-term treatment of sclerosing cholangitis in children, especially those without cirrhosis.

Enhancement of macrophage stimulation by lipoteichoic acid and the costimulant hemoglobin is dependent on Toll-like receptors 2 and 4.

Macrophage stimulation by lipoteichoic acid (LTA) and hemoglobin (Hb) requires Toll-like receptors 2 and 4 (TLR2 and -4). There are two distinct temporal phases of interleukin-6 (IL-6) production. The first results in a slight enhancement of IL-6 secretion in response to LTA plus Hb compared to that with LTA alone and is TLR4 independent. The second requires TLR4 and accounts for most of the additional stimulation seen with LTA plus Hb.

Bicyclo[3.1.0]hexyl urea melanin concentrating hormone (MCH) receptor-1 antagonists: impacting hERG liability via aryl modifications.

Herein, we report the discovery of an effective strategy to modulate liabilities related to affinity of previously disclosed bicyclohexane MCHR-1 antagonists for the hERG channel. This paper describes one of several strategies incorporated to limit hERG binding via modifications of a terminal aryl group in an otherwise promising bicyclohexyl urea series.

Monocyte and macrophage activation by lipoteichoic Acid is independent of alanine and is potentiated by hemoglobin.

Lipoteichoic acids (LTAs) are Gram-positive bacterial cell wall components that elicit mononuclear cell cytokine secretion. Cytokine-stimulating activity is thought to be dependent on retaining a high level of ester-linked D-alanine residues along the polyglycerol phosphate backbone. However, Streptococcus pyogenes LTA essentially devoid of D-alanine caused human and mouse cells to secrete as much IL-6 as LTA with a much higher D-alanine content. Furthermore, hemoglobin (Hb) markedly potentiates the stimulatory effect of various LTAs on mouse macrophages or human blood cells, regardless of their d-alanine content. LTA and Hb appear to form a molecular complex, based on the ability of each to affect the other's migration on native acrylamide gels, their comigration on these gels, and the ability of LTA to alter the absorption spectra of Hb. Because S. pyogenes is known to release LTA and secrete at least two potent hemolytic toxins, LTA-Hb interactions could occur during streptococcal infections and might result in a profound alteration of the local inflammatory response.

Piperazine-based CCR5 antagonists as HIV-1 inhibitors. IV. Discovery of 1-[(4,6-dimethyl-5-pyrimidinyl)carbonyl]- 4-[4-[2-methoxy-1(R)-4-(trifluoromethyl)phenyl]ethyl-3(S)-methyl-1-piperazinyl]- 4-methylpiperidine (Sch-417690/Sch-D), a potent, highly selective, and orally bioavailable CCR5 antagonist.

The nature and the size of the benzylic substituent are shown to be the key to controlling receptor selectivity (CCR5 vs M1, M2) and potency in the title compounds. Optimization of the lead benzylic methyl compound 3 led to the methoxymethyl analogue 30, which had excellent receptor selectivity and oral bioavailability in rats and monkeys. Compound 30 (Sch-417690/Sch-D), a potent inhibitor of HIV-1 entry into target cells, is currently in clinical trials.

Biological evaluation and interconversion studies of rotamers of SCH 351125, an orally bioavailable CCR5 antagonist.

The separation and biological evaluation of rotamers as well as interconversion studies on rotamers of our clinical candidate SCH 351125 are described.