Eastern Canadian Colorectal Cancer Consensus Conference 2017.

The annual Eastern Canadian Gastrointestinal Cancer Consensus Conference 2017 was held in St. John's, Newfoundland and Labrador, 28-30 September. Experts in radiation oncology, medical oncology, surgical oncology, and cancer genetics who are involved in the management of patients with gastrointestinal malignancies participated in presentations and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses multiple topics in the management of gastric, rectal, and colon cancer, including ■ identification and management of hereditary gastric and colorectal cancer (crc);■ palliative systemic therapy for metastatic gastric cancer;■ optimum duration of preoperative radiation in rectal cancer-that is, short- compared with long-course radiation;■ management options for peritoneal carcinomatosis in crc;■ implications of tumour location for treatment and prognosis in crc; and■ new molecular markers in crc.

Defining the role of corticotropin releasing factor binding protein in alcohol consumption.

The corticotropin releasing factor (CRF) exerts its effects by acting on its receptors and on the binding protein (CRFBP), and has been implicated in alcohol use disorder (AUD). Therefore, identification of the exact contribution of each protein that mediates CRF effects is necessary to design effective therapeutic strategies for AUD. A series of in vitro/in vivo experiments across different species were performed to define the biological discrete role of CRFBP in AUD. First, to establish the CRFBP role in receptor signaling, we developed a novel chimeric cell-based assay and showed that CFRBP full length can stably be expressed on the plasma membrane. We discovered that only CRFBP(10 kD) fragment is able to potentiate CRF-intracellular Ca2+ release. We provide evidence that CRHBP gene loss increased ethanol consumption in mice. Then, we demonstrate that selective reduction of CRHBP expression in the center nucleus of the amygdala (CeA) decreases ethanol consumption in ethanol-dependent rats. CRFBP amygdalar downregulation, however, does not attenuate yohimbine-induced ethanol self-administration. This effect was associated with decreased hemodynamic brain activity in the CRFBP-downregulated CeA and increased hemodynamic activity in the caudate putamen during yohimbine administration. Finally, in alcohol-dependent patients, genetic variants related to the CRFBP(10 kD) fragment were associated with greater risk for alcoholism and anxiety, while other genetic variants were associated with reduced risk for anxiety. Taken together, our data provide evidence that CRFBP may possess both inhibitory and excitatory roles and may represent a novel pharmacological target for the treatment of AUD.

Varenicline decreases ethanol intake and increases dopamine release via neuronal nicotinic acetylcholine receptors in the nucleus accumbens.

BACKGROUND AND PURPOSE: Varenicline, a neuronal nicotinic acetylcholine receptor (nAChR) modulator, decreases ethanol consumption in rodents and humans. The proposed mechanism of action for varenicline to reduce ethanol consumption has been through modulation of dopamine (DA) release in the nucleus accumbens (NAc) via α4*-containing nAChRs in the ventral tegmental area (VTA). However, presynaptic nAChRs on dopaminergic terminals in the NAc have been shown to directly modulate dopaminergic signalling independently of neuronal activity from the VTA. In this study, we determined whether nAChRs in the NAc play a role in varenicline's effects on ethanol consumption. EXPERIMENTAL APPROACH: Rats were trained to consume ethanol using the intermittent-access two-bottle choice protocol for 10 weeks. Ethanol intake was measured after varenicline or vehicle was microinfused into the NAc (core, shell or core-shell border) or the VTA (anterior or posterior). The effect of varenicline treatment on DA release in the NAc was measured using both in vivo microdialysis and in vitro fast-scan cyclic voltammetry (FSCV). KEY RESULTS: Microinfusion of varenicline into the NAc core and core-shell border, but not into the NAc shell or VTA, reduced ethanol intake following long-term ethanol consumption. During microdialysis, a significant enhancement in accumbal DA release occurred following systemic administration of varenicline and FSCV showed that varenicline also altered the evoked release of DA in the NAc. CONCLUSION AND IMPLICATIONS: Following long-term ethanol consumption, varenicline in the NAc reduces ethanol intake, suggesting that presynaptic nAChRs in the NAc are important for mediating varenicline's effects on ethanol consumption.

Characterization of Giardia lamblia genotypes in dogs from Tucson, Arizona using SSU-rRNA and ß-giardin sequences.

The objective of this study was to determine if human genotypes of Giardia lamblia could be found in canine companion animals from urban and peri-urban environments in Tucson, Arizona. Canine fecal samples collected from the Humane Society of Southern Arizona between July 2006 and April 2009 were screened for G. lamblia infection using immunofluorescent microscopy and confirmed by polymerase chain reaction (PCR). Of the 672 samples screened, 196 were found positive by IFA and 185 of those positive were successfully amplified through PCR. Sequencing analysis showed samples were primarily of the C or D genotypes (n =154), or showing a mix of the C and D genotypes (n =10). One sample showed a mixed infection of a human genotype (A) and a dog-specific genotype (C). These data are consistent with previous studies showing dog specific genotypes to be dominant in environments where dog-to-dog transmission is likely to occur, and provides further evidence that multiple genes should be targeted for more accurate genotype characterization.

Post-coital haemoperitoneum: a downside to intercourse.

We present the case of a 43-year-old multiparous female patient presenting with post-coital haemoperitoneum secondary to a ruptured uterine fibroid. This is a rare case demonstrating the need to elicit full gynaecological history in patients presenting with an acute abdomen.

Lifting the lid on GPCRs: the role of extracellular loops.

GPCRs exhibit a common architecture of seven transmembrane helices (TMs) linked by intracellular loops and extracellular loops (ECLs). Given their peripheral location to the site of G-protein interaction, it might be assumed that ECL segments merely link the important TMs within the helical bundle of the receptor. However, compelling evidence has emerged in recent years revealing a critical role for ECLs in many fundamental aspects of GPCR function, which supported by recent GPCR crystal structures has provided mechanistic insights. This review will present current understanding of the key roles of ECLs in ligand binding, activation and regulation of both family A and family B GPCRs.

Extracellular loops and ligand binding to a subfamily of Family A G-protein-coupled receptors.

GPCRs (G-protein-coupled receptors) are a large family of structurally related proteins which mediate their effects by coupling to G-proteins. The V(1a)R (V(1a) vasopressin receptor) is a member of a family of related GPCRs that are activated by vasopressin {AVP ([Arg(8)]vasopressin)}, OT (oxytocin) and related peptides. These receptors are members of a subfamily of Family A GPCRs called the neurohypophysial peptide hormone receptor family. GPCRs exhibit a conserved tertiary structure comprising a bundle of seven TM (transmembrane) helices linked by alternating ECLs (extracellular loops) and ICLs (intracellular loops). The cluster of TM helices is functionally important for ligand binding, and, furthermore, activation of GPCRs involves movement of these TM helices. Consequently, it might be assumed that the extracellular face of GPCRs is composed of peptide linkers that merely connect important TM helices. However, using a systematic mutagenesis approach and focusing on the N-terminus and the second ECL of the V(1a)R, we have established that these extracellular domains fulfil a range of important roles with respect to GPCR signalling, including agonist binding, ligand selectivity and receptor activation.

Ligand binding and activation of the CGRP receptor.

The receptor for CGRP (calcitonin gene-related peptide) is a heterodimer between a GPCR (G-protein-coupled receptor), CLR (calcitonin receptor-like receptor) and an accessory protein, RAMP1 (receptor activity-modifying protein 1). Models have been produced of RAMP1 and CLR. It is likely that the C-terminus of CGRP interacts with the extracellular N-termini of CLR and RAMP1; the extreme N-terminus of CLR is particularly important and may interact directly with CGRP and also with RAMP1. The N-terminus of CGRP interacts with the TM (transmembrane) portion of the receptor; the second ECL (extracellular loop) is especially important. Receptor activation is likely to involve the relative movements of TMs 3 and 6 to create a G-protein-binding pocket, as in Family A GPCRs. Pro(321) in TM6 appears to act as a pivot. At the base of TMs 2 and 3, Arg(151), His(155) and Glu(211) may form a loose equivalent of the Family A DRY (Asp-Arg-Tyr) motif. Although the details of this proposed activation mechanism clearly do not apply to all Family B GPCRs, the broad outlines may be conserved.

Heterodimers and family-B GPCRs: RAMPs, CGRP and adrenomedullin.

RAMPs (receptor activity-modifying proteins) are single-pass transmembrane proteins that associate with certain family-B GPCRs (G-protein-coupled receptors). Specifically for the CT (calcitonin) receptor-like receptor and the CT receptor, this results in profound changes in ligand binding and receptor pharmacology, allowing the generation of six distinct receptors with preferences for CGRP (CT gene-related peptide), adrenomedullin, amylin and CT. There are three RAMPs: RAMP1-RAMP3. The N-terminus appears to be the main determinant of receptor pharmacology, whereas the transmembrane domain contributes to association of the RAMP with the GPCR. The N-terminus of all members of the RAMP family probably contains two disulphide bonds; a potential third disulphide is found in RAMP1 and RAMP3. The N-terminus appears to be in close proximity to the ligand and plays a key role in its binding, either directly or indirectly. BIBN4096BS, a CGRP antagonist, targets RAMP1 and this gives the compound very high selectivity for the human CGRP(1) receptor.

The pharmacology of CGRP-responsive receptors in cultured and transfected cells.

Historically, CGRP receptors have been classified as CGRP(1) or CGRP(2) subtypes, chiefly depending on their affinity for the antagonist CGRP(8-37). It has been shown that the complex between calcitonin receptor-like receptor (CRLR or CL) and receptor activity modifying protein (RAMP) 1 provides a molecular correlate for the CGRP(1) receptor; however, this does not explain the range of affinities seen for CGRP(8-37) in isolated tissues. It is suggested that these may largely be explained by a combination of methodological factors and CGRP-responsive receptors generated by CL and RAMP2 or RAMP3 and complexes of RAMPs with the calcitonin receptor.

Nurse endoscopy in a district general hospital.

INTRODUCTION: This study describes the first full year of independent practice by a newly appointed nurse endoscopist in a district general hospital. PATIENTS AND METHODS: Patients underwent either 'one stop' flexible sigmoidoscopy and barium enema or flexible sigmoidoscopy alone. Barium enema results, video photography, clinical follow-up, and histology were used to validate the results of the flexible sigmoidoscopy. One stop clinic: 161 endoscopies were performed, with 104 female patients (65%), and a mean age of 64 years. There was one failed endoscopy due to poor bowel preparation. Abnormalities were identified in 84% of endoscopies. Flexible sigmoidoscopy detected abnormalities not seen on the barium enema in 28 cases, all of which were polyps (18%). Barium enema identified one abnormality within reach of the flexible sigmoidoscope not identified at endoscopy (small polyp in sigmoid; 1%). Elective flexible sigmoidoscopy list: 121 endoscopies were performed, with 65 female patients (54%), and a mean age of 59 years. There were two failed endoscopy procedures, both attributed to poor bowel preparation. Two-thirds of patients had an abnormality on investigation. There were no complications in either group of patients. CONCLUSIONS: The nurse-led endoscopy service has been successfully initiated with a high completion rate for flexible sigmoidoscopies. All significant conditions were identified with 99% sensitivity. Nurse endoscopy is a safe, useful and practical procedure in the setting of this district general hospital.

Agonist binding to peptide hormone receptors.

A fundamental issue in molecular pharmacology is to define how agonist-receptor interaction differs from that of antagonist-receptor interaction. The V(1a) vasopressin receptor (V(1a)R) is a member of a family of related G-protein-coupled receptors (GPCRs) that are activated by vasopressin, oxytocin (OT) and related peptides. A segment of the N-terminus that was required for agonist binding, but not antagonist binding, was identified by characterizing truncated V(1a)R constructs. Site-directed mutagenesis revealed that a single residue (Arg(46)) was critical for agonist binding and receptor activation. The N-terminus of the related OT receptor (OTR) could recover agonist binding in a chimaeric OTR(N)-V(1a)R construct. Furthermore, Arg(34) of the human OTR, which corresponds to Arg(46) of the rat V(1a)R, provided agonist-specific binding epitopes in the OTR, indicating a conserved function of this locus throughout this GPCR subfamily. Mutation of Arg(46) revealed that high-affinity agonist binding had an absolute requirement for arginine at this position.

The potential for biofilm growth in water distribution systems.

Biofilms on pipe walls in water distribution systems are composed of bacteria in a polymeric matrix, which can lead to chlorine demand, coliform growth, pipe corrosion and water taste and odour problems. The majority of previous studies have been laboratory or pilot plant based and few results are available for field conditions. In this study, field observations of biofilm were made using biofilm potential monitors. The monitor results were compared with pipe samples taken from the distribution system and with laboratory pipe reactors. An empirical equation quantified the inhibitory effects of free chlorine and decrease of temperature on biofilm growth. With water having total organic carbon concentrations in the range 1.5-3.9mg/1 a free chlorine residual of 0.2 mg/l was needed to reduce biofilm concentration to below 50 pg ATP cm2. Pipe material influenced biofilm activity far less than chlorine with mean biofilm activity being ranked in the order glass (136 pg ATP/cm2) < cement (212 pg ATP/cm2) < MDPE (302 pg ATP/ cm2) < PVC (509 pg ATP/cm2).

Use of herpes simplex virus (HSV) type 1 ISCOMS 703 vaccine for prophylactic and therapeutic treatment of primary and recurrent HSV-2 infection in guinea pigs.

The effect of subunit vaccination on the incidence and severity of primary and recurrent genital herpes was investigated in the female guinea pig model of herpes simplex virus (HSV) type 2 genital infection. After prophylactic immunization with zwitterionic detergent-solubilized HSV-1 glycoproteins formulated with alhydrogel or as immunostimulating complex particles, significant reductions in the incidence and severity of primary herpetic illness were observed in both vaccinated groups compared with immunization-naive controls. There was a significant reduction in the incidence of spontaneous herpetic recurrences after administration of HSV-1 antigens formulated as immunostimulatory complexes to guinea pigs in a prophylactic mode (P<.01). Increased levels of both postimmunization and postchallenge ELISA and neutralizing antibodies were significant correlates of protection against primary herpetic disease in a prophylactic scenario. However, no correlation was observed between elevated ELISA or neutralizing antibody levels and protection against recurrent disease following prophylactic or therapeutic administration of HSV-1 subunit vaccines.

Adjuvants and delivery systems for viral vaccines--mechanisms and potential.

Of the vaccines against viral diseases of man currently available, several are less than satisfactory, and the present surge of interest in improving such vaccines, and in developing new vaccines against viral diseases as yet unchallenged, has led to major developments in three areas. The capacity to identify the nature and form of antigenic epitopes in proteins allows the specific design of molecular entities to promote relevant and protective immune responses. Such entities, although ideal in terms of specificity and purity, may not achieve their goals through failure to reach relevant cells of the immune system due to simple dilution, elimination by host enzymes or lack of specific targeting. Concomitant with the above there has been development of a plethora of adjuvants aimed at enhancing immune responses to these 'new' immunogens, paralleled by an almost equally rapid increase in understanding the complex nature of the immune response, particularly with respect to antigen processing, the nature and role of cytokines and the importance of T-cell subsets in infection. These developments allow exploration of matching the properties and mechanistic action of a given adjuvant to a defined immune response. Adjuvants can be grouped according to their physical characteristics and mode of action. They include particulate adjuvants, oil and emulsifier-based adjuvants, those providing controlled antigen delivery, adjuvants based on specific targeting of antigen, and gel-type adjuvants. They may act non-specifically in promoting an immune response to an antigen through depot formation, or very specifically as in a "delivery system" where an antigen is linked to a cellular protein, targeted to a specific cell receptor. As adjuvant technology develops it is becoming increasingly clear that these differing approaches may be combined, and an adjuvant/delivery system designed, to provide slow release of a targeted antigen. The role of adjuvants in modern viral vaccine technology and their influence on the immune system are the subject of this review.

Humoral response to HSV-1 subunit vaccines--a statistical analysis.

Following primary infection with HSV, the virus becomes latent in the local sensory ganglia for the lifetime of the host. In some cases, periodic reactivation may occur due to various stimuli and cause a recrudescent lesion at or near the initial site of infection. As yet there is no suitable vaccine to prevent its spread within the human population. We investigated the potential of a large number of commercial and experimental adjuvant preparations to enhance the immunogenicity of an HSV-1 glycoprotein subunit vaccine. Evaluation was based on toxicity, total antibody titre, neutralizing antibody production and protection against lethal challenge. All adjuvants tested increased the titre of antigen specific total and neutralizing lg when compared to subunit vaccine alone, although functional neutralising antibody was only detected in some cases. Following challenge, a broad range of protective responses was noted but no correlation between antibody levels and protection was observed. The results emphasize the requirement of adjuvants when using subunit preparations as vaccine formulations and demonstrate that the magnitude and effectiveness of the induced immune response varies greatly with the choice of adjuvant.