Publications by authors named "Brodkin J"

Introduction: Gastric cancer is the fifth most common cancer worldwide and the fourth most common cause of cancer-related death. Two molecular subtyping classifications were recently introduced: The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG) classifications.

Methods: We classified a cohort of 283 gastric cancer patients undergoing surgery at Helsinki University Hospital between 2000 and 2009.

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Abnormal vasculature in tumors leads to poor tissue perfusion and cytostatic drug delivery. Although drugs inducing vascular normalization, for example, angiopoietin-2 (Ang2)-blocking antibodies, have shown promising results in preclinical tumor models, clinical studies have so far shown only little efficacy. Because Ang2 is known to play a protective role in stressed endothelial cells, we tested here whether Ang2 blocking could enhance radiation-induced tumor vascular damage.

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The proper functions of cortical circuits are dependent upon both appropriate neuronal subtype specification and their maturation to receive appropriate signaling. These events establish a balanced circuit that is important for learning, memory, emotion, and complex motor behaviors. Recent research points to mRNA metabolism as a key regulator of this development and maturation process.

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Background: Behavioral assessment of mutant mouse models and novel candidate drugs is a slow and labor intensive process. This limitation produces a significant impediment to CNS drug discovery.

New Method: By combining video and vibration analysis we created an automated system that provides the most detailed description of mouse behavior available.

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The highly potent, selective, and brain-penetrant metabotropic glutamate subtype 5 (mGlu5) receptor antagonists 3-(5-pyridin-2-yl-2H-tetrazol-2-yl)benzonitrile (47) and 3-fluoro-5-(5-pyridin-2-yl-2H-tetrazol-2-yl)benzonitrile (48) are reported. Compound 47 is active in the rat fear-potentiated startle (FPS) model of anxiety with ED(50) = 5.4 mg/kg (po) when dosed acutely.

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Previous reports have demonstrated the anxiolytic effect of the potent and systemically active metabotropic glutamate subtype 5 (mGlu5) receptor antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP) in rodents. Here, we present evidence for the anxiolytic activity of a novel mGlu5 receptor antagonist, 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP), in rats and compare its profile to the benzodiazepine receptor agonist diazepam. MTEP occupied mGlu5 receptors in a dose-dependent manner with essentially full receptor occupancy at the highest dose tested (10 mg/kg, i.

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Structure-activity relationship studies leading to the discovery of a new, orally active mGlu5 receptor antagonist are described. The title compound, 5-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-2,3'-bipyridine, is highly potent in vitro, has good in vivo receptor occupancy, and is efficacious in the rat fear-potentiated startle model of anxiety following oral dosing.

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A series of potent and selective mGluR5 antagonists were synthesized and evaluated in vitro and in vivo. It was found that a pyridyl functionality is a potential replacement for acetonitrile in the lead structure, with 2-pyridyl being most favored. Additionally, the benzoxazole moiety could also be replaced by other heterobicyclic rings such as imidazothiazole.

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The present experiments characterized the acquisition of fear-potentiated startle (FPS) and determined the sensitivity of FPS to anxiolytic compounds in DBA/1J mice. A light (30 s) conditioned stimulus (CS) and mild footshock (0.14 mA, 0.

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2-Methyl-6-(phenylethynyl)pyridine (3), a potent noncompetitive mGlu5 receptor antagonist widely used to characterize the pharmacology of mGlu5 receptors, suffers from a number of shortcomings as a therapeutic agent, including off-target activity and poor aqueous solubility. Seeking to improve the properties of 3 led to the synthesis of compound 9, a highly selective mGlu5 receptor antagonist that is 5-fold more potent than 3 in the rat fear-potentiated startle model of anxiety.

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It hs been suggested that metabotropic glutamate receptor subtype 5 (mGluR5) play a role in the expression of anxiety, based on anxiolytic-like effects of the selective mGluR5 antagonist MPEP (2-methyl-6-(phenylethynyl)pyridine) in rodent models of anxiety, including stress-induced hyperthermia (SIH). To examine the suggested role of mGlu5 receptors in the expression of anxiety, we examined the stress response in mice lacking mGluR5 in several variations of the SIH procedure. In this paradigm, stress causes a mild increase in body temperature that can be blocked by known anxiolytic agents.

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The selective and systemically active antagonist for the metabotropic glutamate receptor subtype 5 (mGluR5), 2-methyl-6-(phenylethynyl)pyridine (MPEP) was shown to display anxiolytic-like activity in a number of unconditioned assays of stress and anxiety (elevated plus maze, shock probe burying, marble burying, social interaction, and stress-induced hyperthermia) in rodents. In this report, we extend these observations found using unconditioned models of anxiety to include three models of conditioned anxiety, comparing the activity of MPEP to the clinically used anxiolytics, diazepam, and buspirone. MPEP and diazepam, but not buspirone, showed anxiolytic-like activity in the fear-potentiated startle (FPS) model.

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Muscarinic acetylcholine receptors (M1-M5) play important roles in the modulation of many key functions of the central and peripheral nervous system. To explore the physiological roles of the two Gi-coupled muscarinic receptors, we disrupted the M2 and M4 receptor genes in mice by using a gene targeting strategy. Pharmacological and behavioral analysis of the resulting mutant mice showed that the M2 receptor subtype is critically involved in mediating three of the most striking central muscarinic effects, tremor, hypothermia, and analgesia.

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Rationale: Epidemiological studies of smokers suggest that there is a link between nicotine and depression. Nonetheless, few studies have examined the potential use of nicotinic ligands in the treatment of depression.

Objectives: The goal of this study was to evaluate the effects of SIB-1508Y, a novel subtype-selective ligand for high affinity nicotinic acetylcholine receptors (nAChRs), in the learned helplessness model of depression in rats.

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Isobolograms are used to identify synergistic effects of drugs given in combination. However, the traditional isobologram provides only a qualitative determination of synergism. The present report describes two procedures for quantifying the synergistic actions of drugs based on isobolographic plots.

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The present experiments investigated the validity and utility of measuring the habituation of a nose-poke response to assess memory in mice. Mice were placed in an operant chamber equipped with two holes in one wall. Nose-poke responses were recorded by the interruption of a photo-beam across the openings of the holes.

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Muscarinic acetylcholine receptors (M(1)-M(5)) regulate many key functions of the central and peripheral nervous system. Primarily because of the lack of receptor subtype-selective ligands, the precise physiological roles of the individual muscarinic receptor subtypes remain to be elucidated. Interestingly, the M(4) receptor subtype is expressed abundantly in the striatum and various other forebrain regions.

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Members of the muscarinic acetylcholine receptor family (M1-M5) are known to be involved in a great number of important central and peripheral physiological and pathophysiological processes. Because of the overlapping expression patterns of the M1-M5 muscarinic receptor subtypes and the lack of ligands endowed with sufficient subtype selectivity, the precise physiological functions of the individual receptor subtypes remain to be elucidated. To explore the physiological roles of the M2 muscarinic receptor, we have generated mice lacking functional M2 receptors by using targeted mutagenesis in mouse embryonic stem cells.

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The effects of cannabinoid ligands were studied in rats responding under a repeated acquisition procedure. Each session rats were required to learn a different three-response sequence; every third correct completion of the sequence resulted in the presentation of a food pellet. Errors produced a brief timeout but did not reset the chain.

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A technique is described that allowed percutaneous retrieval of an endoscopically placed, obstructed biliary stent using loop snare capture of an angled hydrophilic wire which was wrapped around the stent initially.

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A novel, inexpensive apparatus (locometer) was designed to measure behavioral activity of rats including gross locomotor activity, rearing, and structural characteristics of movement patterns (i.e. fractal dimension).

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The effect of the R(-) and S(+) isomers of 3,4-methylenedioxyamphetamine (MDA) and its N-methyl analog 3,4-methylenedioxymethamphetamine (MDMA) on [3H]inositol monophosphate accumulation was studied in cells expressing either 5-HT2A or 5-HT2C receptors. The isomers of MDA produced a concentration dependent increase in phosphatidyl inositol (PI) hydrolysis at the 5-HT2A receptors, with the R(-) isomer of MDA being more potent than the S(+) at the 5-HT2A receptor. The R(-) and S(+) isomers of MDMA were significantly less efficacious at the 5-HT2A receptor as compared to MDA; S(+)MDMA had no effect.

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The effect of acute, reversible depletion of either serotonin [5-hydroxytryptamine (5-HT)] or dopamine (DA) on the long-term (7-day) decrease of brain 5-HT content produced after 3,4-methylenedioxymethamphetamine (MDMA) administration was investigated. The tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine (alpha-MPT) significantly attenuated the acute increase in DA efflux produced by MDMA in the striatum as measured by in vivo microdialysis. Treatment with alpha-MPT had no effect on MDMA-induced 5-HT release.

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The effect of dopamine (DA) and serotonin (5-HT) uptake inhibitors on 3,4-methylenedioxymethamphetamine (MDMA)-induced increase in DA efflux was studied using in vivo microdialysis. MDMA was infused directly into the anterolateral striatum via the dialysis probe. The local administration of MDMA produced a dose- and time-dependent increase in the extracellular concentration of DA in the striatum.

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