In silico design of novel probes for the atypical opioid receptor MRGPRX2.

The primate-exclusive MRGPRX2 G protein-coupled receptor (GPCR) has been suggested to modulate pain and itch. Despite putative peptide and small-molecule MRGPRX2 agonists, selective nanomolar-potency probes have not yet been reported. To identify a MRGPRX2 probe, we first screened 5,695 small molecules and found that many opioid compounds activated MRGPRX2, including (-)- and (+)-morphine, hydrocodone, sinomenine, dextromethorphan, and the prodynorphin-derived peptides dynorphin A, dynorphin B, and α- and ß-neoendorphin. We used these to select for mutagenesis-validated homology models and docked almost 4 million small molecules. From this docking, we predicted ZINC-3573-a potent MRGPRX2-selective agonist, showing little activity against 315 other GPCRs and 97 representative kinases-along with an essentially inactive enantiomer. ZINC-3573 activates endogenous MRGPRX2 in a human mast cell line, inducing degranulation and calcium release. MRGPRX2 is a unique atypical opioid-like receptor important for modulating mast cell degranulation, which can now be specifically modulated with ZINC-3573.

Community-Acquired Pneumonia Requiring Hospitalization among U.S. Adults.

BACKGROUND: Community-acquired pneumonia is a leading infectious cause of hospitalization and death among U.S. adults. Incidence estimates of pneumonia confirmed radiographically and with the use of current laboratory diagnostic tests are needed. METHODS: We conducted active population-based surveillance for community-acquired pneumonia requiring hospitalization among adults 18 years of age or older in five hospitals in Chicago and Nashville. Patients with recent hospitalization or severe immunosuppression were excluded. Blood, urine, and respiratory specimens were systematically collected for culture, serologic testing, antigen detection, and molecular diagnostic testing. Study radiologists independently reviewed chest radiographs. We calculated population-based incidence rates of community-acquired pneumonia requiring hospitalization according to age and pathogen. RESULTS: From January 2010 through June 2012, we enrolled 2488 of 3634 eligible adults (68%). Among 2320 adults with radiographic evidence of pneumonia (93%), the median age of the patients was 57 years (interquartile range, 46 to 71); 498 patients (21%) required intensive care, and 52 (2%) died. Among 2259 patients who had radiographic evidence of pneumonia and specimens available for both bacterial and viral testing, a pathogen was detected in 853 (38%): one or more viruses in 530 (23%), bacteria in 247 (11%), bacterial and viral pathogens in 59 (3%), and a fungal or mycobacterial pathogen in 17 (1%). The most common pathogens were human rhinovirus (in 9% of patients), influenza virus (in 6%), and Streptococcus pneumoniae (in 5%). The annual incidence of pneumonia was 24.8 cases (95% confidence interval, 23.5 to 26.1) per 10,000 adults, with the highest rates among adults 65 to 79 years of age (63.0 cases per 10,000 adults) and those 80 years of age or older (164.3 cases per 10,000 adults). For each pathogen, the incidence increased with age. CONCLUSIONS: The incidence of community-acquired pneumonia requiring hospitalization was highest among the oldest adults. Despite current diagnostic tests, no pathogen was detected in the majority of patients. Respiratory viruses were detected more frequently than bacteria. (Funded by the Influenza Division of the National Center for Immunizations and Respiratory Diseases.).

Bupropion and its main metabolite reverse nicotine chronic tolerance in the mouse.

INTRODUCTION: Although the antidepressant bupropion is prescribed to aid in smoking cessation, little is known concerning its mechanisms of action in this regard. One factor that might influence quit success is nicotine tolerance, which could promote high levels of nicotine intake in order to maintain nicotine's subjective effects (thereby making attempts to reduce smoking more difficult). METHODS: To explore whether bupropion and its active hydroxymetabolite modulate nicotine tolerance, mice were injected for 14 days with saline or nicotine. On Day 14, animals received saline, (2S,3S)-hydroxybupropion, or bupropion at different doses. On Day 15, mice were assayed on test day for nicotine-induced analgesia and hypothermia. RESULTS: Animals chronically injected with saline + nicotine developed tolerance to nicotine's effects in both assays. Administration of bupropion and (2S,3S)-hydroxybupropion dose-dependently reversed chronic nicotine tolerance. CONCLUSIONS: These results indicate that bupropion's ability to promote smoking cessation may be partly due to its attenuation of nicotine tolerance since both measured responses of nicotine (antinociception and hypothermia) are mediated to a large extent by neuronal α4ß2* nicotine receptors.

Design, synthesis and biological evaluation of a bi-specific vaccine against α-pyrrolidinovalerophenone (α-PVP) and 3,4-methylenedioxypyrovalerone (MDPV) in rats.

α-PVP (α-pyrrolidinovalerophenone) and MDPV (3,4-methylenedioxypyrovalerone) are potent abused stimulants that are members of the synthetic cathinone class of drugs. Although these drugs are taken with recreational intent, high doses can lead to unintended adverse effects including agitation, cardiovascular effects, sympathomimetic syndromes, hallucinations, and psychoses. One possible treatment is the use of a vaccine to block or attenuate adverse medical effects. These studies report the preparation of a vaccine that generates high affinity antibodies specific for both drugs and the pharmacological testing of this vaccine in male rats. Alkylation of a hydroxy-α-PVP analog with an appropriate thiol-bearing linker afforded the hapten. When hapten-conjugated carrier protein was mixed with adjuvant, the resulting vaccine stimulated production of antibodies in male Sprague Dawley rats that were found to significantly reduce α-PVP- and MDPV-induced hyperlocomotion as well as to significantly reduce the concentrations of MDPV drugs in critical organs. The novel vaccine produced high affinity antibodies against MDPV, (R)-MDPV, (S)-MDPV, and α-PVP. Cross-reactivity testing against nine structurally similar cathinones showed very limited binding, and no binding to off-target endogenous and exogenous compounds. Antibodies generated by this bi-specific vaccine also significantly shortened the duration of locomotor activity induced by both drugs up to a dose of 5.6 mg/kg in male rats.

Community-Acquired Pneumonia Visualized on CT Scans but Not Chest Radiographs: Pathogens, Severity, and Clinical Outcomes.

BACKGROUND: The clinical significance of pneumonia visualized on CT scan in the setting of a normal chest radiograph is uncertain. METHODS: In a multicenter prospective surveillance study of adults hospitalized with community-acquired pneumonia (CAP), we compared the presenting clinical features, pathogens present, and outcomes of patients with pneumonia visualized on a CT scan but not on a concurrent chest radiograph (CT-only pneumonia) and those with pneumonia visualized on a chest radiograph. All patients underwent chest radiography; the decision to obtain CT imaging was determined by the treating clinicians. Chest radiographs and CT images were interpreted by study-dedicated thoracic radiologists blinded to the clinical data. RESULTS: The study population included 2,251 adults with CAP; 2,185 patients (97%) had pneumonia visualized on chest radiography, whereas 66 patients (3%) had pneumonia visualized on CT scan but not on concurrent chest radiography. Overall, these patients with CT-only pneumonia had a clinical profile similar to those with pneumonia visualized on chest radiography, including comorbidities, vital signs, hospital length of stay, prevalence of viral (30% vs 26%) and bacterial (12% vs 14%) pathogens, ICU admission (23% vs 21%), use of mechanical ventilation (6% vs 5%), septic shock (5% vs 4%), and inhospital mortality (0 vs 2%). CONCLUSIONS: Adults hospitalized with CAP who had radiological evidence of pneumonia on CT scan but not on concurrent chest radiograph had pathogens, disease severity, and outcomes similar to patients who had signs of pneumonia on chest radiography. These findings support using the same management principles for patients with CT-only pneumonia and those with pneumonia seen on chest radiography.

Findings on the portable chest radiograph correlate with fluid balance in critically ill patients.

STUDY OBJECTIVES: Fluid balance concerns occur daily in critically ill patients, complicated by difficulties assessing intravascular volume. Chest radiographs (CXRs) quantify pulmonary edema in acute lung injury (ALI) and total blood volume in normal subjects. We hypothesized that CXRs would reflect temporal changes in fluid balance in critically ill patients. DESIGN: Standardized scoring of 133 supine, portable, anteroposterior CXRs. Outcomes included subjective and objective measures of intravascular volume and pulmonary edema. SETTING: Academic university medical center and affiliated Veterans Affairs hospital. PATIENTS: Thirty-seven patients with ALI receiving mechanical ventilation blindly randomized to treatment with diuretics and colloids or dual placebo for 5 days. MEASUREMENTS AND RESULTS: Treated patients experienced a 3.3-L diuresis and 10-kg weight loss during the 5-day period. A significant correlation was observed in all patients between changes in vascular pedicle width (VPW) and net intake/output (r = 0.50, p = 0.01) or weight (r = 0.51, p = 0.01). The correlation between VPW and fluid balance was greatest for weight changes in the treatment group alone (r = 0.71, p = 0.005). Pulmonary artery occlusion pressure correlated highly with changes in VPW (r = 0.70, p < 0.001). After day 1, CXRs revealed significant between-group differences in VPW without changes in cardiothoracic ratio or subjective measures of edema. The proportion of patients with VPW < 70 mm did not differ at baseline but was significantly more in the treatment group on all subsequent days (p < 0.05). CONCLUSIONS: We conclude that temporal fluid balance changes are reflected on commonly utilized portable CXRs. Objective radiographic measures of intravascular volume may be more appropriate indicators of fluid balance than subjective measures, with VPW appearing most sensitive. If systematically quantitated, serial CXRs provide a substantial supplement to other clinically available data for the purpose of fluid management in critically ill patients.

Interview with Frank Ivy Carroll.

Frank Ivy Carroll received his BS degree in chemistry from Auburn University (AL, USA) in 1957 and was awarded the PhD in chemistry by the University of North Carolina at Chapel Hill (NC, USA) in 1961. He joined the research staff of the Research Triangle Institute (NC, USA) as a Research Chemist and rose steadily to the position of Vice President of the Chemistry and Life Sciences Group, a position he held from 1996-2001. Dr Carroll also served as Director of the Center for Organic and Medicinal Chemistry from 1975-2007. He is presently Distinguished Fellow for Medicinal Chemistry. Dr Carroll has varied research interests, but since 1990, a major thrust of his research efforts has involved development of pharmacotherapies for substance abuse (cocaine, nicotine, methamphetamine, opioids and ethanol) and other CNS disorders. Dr Carroll has published 468 peer-reviewed articles, 33 book chapters and 46 patents and has received numerous awards for his research accomplishments; the most recent are: the 2010 North Carolina Award for Science; the 2010 National Institute on Drug Abuse Public Service Award for Significant Achievement; and the 2012 Alfred Burger Award in Medicinal Chemistry from the American Chemical Society. In 2007, he was inducted into the American Chemical Society Medicinal Chemistry Hall of Fame. Interview conducted by Hannah Coaker, Assistant Commissioning Editor.

Effect of the selective kappa-opioid receptor antagonist JDTic on nicotine antinociception, reward, and withdrawal in the mouse.

RATIONALE: Several lines of evidence support a role for the endogenous opioid system in mediating behaviors associated with drug dependence. Specifically, recent findings suggest that the kappa-opioid receptor (KOR) may play a role in aspects of nicotine dependence, which contribute to relapse and continued tobacco smoking. OBJECTIVE: The objective of this study is to determine the involvement of the KOR in the initial behavioral responses of nicotine, nicotine reward, and nicotine withdrawal using the highly selective KOR antagonist JDTic. JDTic doses of 1, 4, 8, or 16 mg/kg were administered subcutaneously (s.c.) 18 h prior to nicotine treatment. RESULTS: JDTic dose-dependently blocked acute nicotine-induced antinociception in the tail-flick but not the hot-plate test and did not significantly attenuate morphine's antinociceptive effect in either the tail-flick or hot-plate test. Furthermore, JDTic (8 and 16 mg/kg, s.c.) failed to block the expression of nicotine reward as measured by the conditioned place preference model. In contrast, JDTic and the KOR antagonist norBNI attenuated the expression of both the physical (somatic signs and hyperalgesia) and affective (anxiety-related behavior and conditioned place aversion) nicotine withdrawal signs. CONCLUSIONS: Our findings clearly show that the KOR is involved in mediating the withdrawal aspects of nicotine dependence. The results from this study suggest that blockade of the KOR by selective KOR antagonists may be useful smoking cessation pharmacotherapies.

Tunable, monochromatic X-rays: an enabling technology for molecular/cellular imaging and therapy.

Pulsed, tunable, monochromatic X-rays hold great potential as a cellular and molecular probe. These beams can be tuned to the binding energy of orbital electrons in atoms, making them extremely useful in diagnostic k-edge imaging and Auger cascade radiotherapy. Their wide tunability makes them ideal for the performance of various techniques as disparate as protein crystallography and three-dimensional, compressionless, monochromatic mammography. Since only the frequency best suited to the task at hand is used, radiation exposure to patients or animals is exceedingly low when compared to standard X-ray techniques.