Exploring the Human Cytomegalovirus Core Nuclear Egress Complex as a Novel Antiviral Target: A New Type of Small Molecule Inhibitors

Nuclear egress is an essential process in the replication of human cytomegalovirus (HCMV), as it enables the migration of newly formed viral capsids from the nucleus into the cytoplasm. Inhibition of the HCMV core nuclear egress complex (core NEC), composed of viral proteins pUL50 and pUL53, has been proposed as a potential new target for the treatment of HCMV infection and disease. Here, we present a new type of small molecule inhibitors of HCMV core NEC formation, which inhibit the pUL50-pUL53 interaction at nanomolar concentrations. These inhibitors, i.e., verteporfin and merbromin, were identified through the screening of the Prestwick Chemical Library^® of approved drug compounds. The inhibitory effect of merbromin is both compound- and target-specific, as no inhibition was seen for other mercury-organic compounds. Furthermore, merbromin does not inhibit an unrelated protein–protein interaction either. More importantly, merbromin was found to inhibit HCMV infection of cells in three different assays, as well as to disrupt HCMV NEC nuclear rim formation. Thus, while not being an ideal drug candidate by itself, merbromin may serve as a blueprint for small molecules with high HCMV core NEC inhibitory potential, as candidates for novel anti-herpesviral drugs.     

Use of arterial transfer functions for the derivation of aortic waveform characteristics

OBJECTIVE: To investigate the utility and accuracy of radial-aortic arterial transfer functions for the derivation of central blood pressure waveforms.DESIGN Prospective measurement of central and peripheral waveforms in patients undergoing coronary angiography or percutaneous coronary intervention. METHODS: Simultaneous invasive central aortic and non-invasive radial pressure waveforms were recorded in 78 subjects (61 male : 17 female). Data were applied to a single-input/single-output model for the calculation of a transfer function (TF). Individual TFs were derived by two methods and ensemble averaged TFs obtained for the group. Reverse transformation was performed using each averaged TF applied to the radial data of each subject. RESULTS: There was close linear correlation between measured aortic parameters and both radial and TF-derived aortic systolic and diastolic pressures (P < 0.001) and most other waveform parameters. However, despite small mean differences between measured and most TF-derived aortic parameters (systolic pressure 0.8-2.9 mmHg, augmentation index 4.3-5.6%), individual scatter was marked, with 95% limits of agreement of +/- 14.6 mmHg (systolic pressure) and +/- 24.4% [augmentation index (AI)]. Indeed, scatter for AI was so marked that measured and derived values were not statistically significantly correlated. CONCLUSIONS: Transfer functions may be valid for the derivation of some central aortic waveform characteristics. However, in providing neither improved reproducibility nor data on parameters not obtainable from the radial waveform, transfer function techniques may offer no additional clinical benefit. The absence of correlation between measured and TF-derived aortic AI and wide limits of agreement of other parameters should be considered if this technique is utilized in clinical practice.     

Amino acid and cDNA sequences of a vascular endothelial cell mitogen that is homologous to platelet-derived growth factor.

Glioma-derived vascular endothelial cell growth factor (GD-VEGF) is a 46-kDa dimeric glycoprotein mitogen with apparently greater specificity for vascular endothelial cells than the well-characterized fibroblast growth factors. The GD-VEGF cDNA sequence encodes a 190-amino acid residue subunit that is converted, by removal of an amino-terminal hydrophobic secretory leader sequence, to the mature 164-residue subunit characterized by direct amino acid sequencing. The GD-VEGF homodimeric subunit is homologous to the platelet-derived growth factor A and B chains and its oncogene homologue v-sis.     

Effect of high-fat diet on glucose homeostasis and gene expression in glucokinase knockout mice

Aim: We have generated a heterozygous glucokinase knockout mouse (gk^del/wt), upon which we investigated the effect of high‐fat diet (HFD) with respect to metabolic control and both hepatic and β‐cell gene expression. We also investigated the in vitro efficacy of a glucokinase activator (GKA) on glucose‐stimulated insulin secretion (GSIS) in gk^del/wtmouse islets. Methods: Male gk^del/wtand gk^wt/wtmice were grouped (n = 8–10) at 10 weeks of age and fed HFD or chow diet (CD) for 10 weeks. Multiple parameters including blood glucose, plasma insulin and glucose tolerance were assessed. Further animal groups were used for in vitro GSIS and islet and liver gene expression analysis. Results and Conclusions: gk^del/wtmice showed early‐onset persistent hyperglycaemia, raised glycated haemoglobin levels, impaired GSIS and glucose tolerance but no change in plasma cholesterol, non‐esterified fatty acids or triglyceride levels. After HFD feeding, insulin levels of gk^del/wtmice were less than half that of gk^wt/wtmice, although they were equivalent to gk^wt/wtmice on CD. While gk^wt/wtmice maintained moderate hyperglycaemia, gk^del/wtmice became overtly diabetic, with worsened glucose tolerance. A GKA (GKA50) increased GSIS, at 10 mM glucose, in gk^del/wtmice to an extent at least as great as that seen in gk^wt/wtmice on both CD and HFD. gk^del/wtmice showed only a small number of changes in gene expression compared with gk^wt/wtmice. We propose the high fat–fed gk^del/wtmouse as a model of type 2 diabetes and report retained efficacy of a GKA on in vitro GSIS.     

Neuronal NADPH diaphorase is a nitric oxide synthase.

NADPH diaphorase histochemistry selectively labels a number of discrete populations of neurons throughout the nervous system. This simple and robust technique has been used in a great many experimental and neuropathological studies; however, the function of this enzyme has remained a matter of speculation. We, therefore, undertook to characterize this enzyme biochemically. With biochemical and immunochemical assays, NADPH diaphorase was purified to apparent homogeneity from rat brain by affinity chromatography and anion-exchange HPLC. Western (immunoblot) transfer and immunostaining with an antibody specific for NADPH diaphorase labeled a single protein of 150 kDa. Nitric oxide synthase was recently shown to be a 150-kDa, NADPH-dependent enzyme in brain. It is responsible for the calcium/calmodulin-dependent synthesis of the guanylyl cyclase activator nitric oxide from L-arginine. We have found that nitric oxide synthase activity and NADPH diaphorase copurify to homogeneity and that both activities could be immunoprecipitated with an antibody recognizing neuronal NADPH diaphorase. Furthermore, nitric oxide synthase was competitively inhibited by the NADPH diaphorase substrate, nitro blue tetrazolium. Thus, neuronal NADPH diaphorase is a nitric oxide synthase, and NADPH diaphorase histochemistry, therefore, provides a specific histochemical marker for neurons producing nitric oxide.     

Palliative management of refractory dyspnea in COPD

COPD is a progressive illness with worldwide impact. Patients invariably reach a point at which they require palliative interventions. Dyspnea is the most distressing symptom experienced by these patients; when not relieved by traditional COPD management strategies it is termed “refractory dyspnea” and palliative approaches are required. The focus of care shifts from prolonging survival to reducing symptoms, increasing function, and improving quality of life. Numerous pharmacological and non-pharmacological interventions can achieve these goals, though evidence supporting their use is variable. This review provides a summary of the options for the management of refractory dyspnea in COPD, outlining currently available evidence and highlighting areas for further investigation. Topics include oxygen, opioids, psychotropic drugs, inhaled furosemide, Heliox, rehabilitation, nutrition, psychosocial support, breathing techniques, and breathlessness clinics.     

Canadian Association of Gastroenterology policy on the application for,and implementation of,clinical practice guidelines

An important mandate of the Canadian Association of Gastroenterology (CAG), as documented in the Association’s governance policies, is to optimize the care of patients with digestive disorders. Clinical practice guidelines are one means of achieving this goal. The benefits of timely, high-quality and evidenced-based recommendations include:

• Enhancing the professional development of clinical members through education and dissemination of synthesized clinical research;
• Improving patient care provided by members by providing focus on quality and evidence;
• Creating legislative environments that favour effective clinical practice;
• Enhancing the clinical care provided to patients with digestive disease by nongastroenterologists; and
• Identifying areas that require further information or research to improve clinical care.

The present document provides the foundation required to ensure that clinical practice guidelines produced by the CAG are necessary, appropriate, credible and applicable. These recommendations should be adhered to as closely as possible to obtain CAG endorsement.