Novel selective antagonist radioligands for the pharmacological study of A2B adenosine receptors

The adenosine A2B receptor is the least well characterized of the four adenosine subtypes due to the lack of potent and selective agonists and antagonists. Despite the widespread distribution of A2B receptor mRNA, little information is available with regard to their function. The characterization of A2B receptors, through radioligand binding studies, has been performed, until now, by using low-affinity and non-selective antagonists like 1,3-dipropyl-8-cyclopentylxanthine ([3H]DPCPX),(4-(2-[7-amino-2-(2-furyl)-[1,2,4]triazolo-[2,3-a][1,3,5]triazin-5-ylamino]ethyl)-phenol ([3H]ZM 241385) and 3-(3,4-aminobenzyl)-8-(4-oxyacetate)phenyl-1-propyl-xanthine ([125I]ABOPX). Recently, high-affinity radioligands for A2B receptors, [N-(4-cyanophenyl)-2-[4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)-phenoxy]acetamide ([3H]MRS 1754), N-(2-(2-Phenyl-6-[4-(2,2,3,3-tetratritrio-3-phenylpropyl)-piperazine-1-carbonyl]-7H-pyrrolo[2,3-d]pyrimidin-4-ylamino)-ethyl)-acetamide ([3H]OSIP339391) and N-benzo[1,3]dioxol-5-yl-2-[5-(1,3-dipropyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl)-1-methyl-1H-pyrazol-3-yloxy]-acetamide] ([3H]MRE 2029F20), have been introduced. This minireview offers an overview of these recently developed radioligands and the most important applications of drugs towards A2B receptors

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A

On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is $5.0\times {10}^{-8}$. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of $(+1.74\pm 0.05)\,{\rm{s}}$ between GRB 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between $-3\times {10}^{-15}$ and $+7\times {10}^{-16}$ times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1-1.4 per year during the 2018-2019 observing run and 0.3-1.7 per year at design sensitivity

Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 × 10−21. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410þ160 −180 Mpc corresponding to a redshift z ¼ 0.09þ0.03 −0.04 . In the source frame, the initial black hole masses are 36þ5 −4M⊙ and 29þ4 −4M⊙, and the final black hole mass is 62þ4 −4M⊙, with 3.0þ0.5 −0.5M⊙c2 radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger

First Measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary-Black-hole Merger GW170814

We present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in ${H}_{0}={75}_{-32}^{+40}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$, which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find {H}_{0 {78}_{-24}^{+96}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1} (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Investigation of sexually transmitted protozoan parasite Tritrichomonas foetus in cattle in Bangladesh

Bovine trichomoniasis is a venereal disease caused by the protozoa Tritrichomonas foetus. The aim of the study was to investigate the prevalence of T. foetus in cattle and associated risk factors. A total of 200 samples from 183 cows and 17 bulls were collected from Veterinary Teaching Hospital, Bangladesh Agricultural University; Mymensingh district and Regional station of Bangladesh Livestock Research Institute in Shahjadpur, Sirajgonj during the period from March 2015 to May 2016. Among 200 cattle, 65 were indigenous, 100 were Holstein cross and 35 were Shahiwal cross bred. The collected samples were vaginal and uterine washing, aborted foetus and semen. The samples were collected from vagina and uterus by flashing with phosphate buffer solution by artificial insemination tube connected with 20 ml syringe. The samples were examined for T. foetus under microscope. The samples were examined on the same day of collection. Out of 200 samples examined, 3 (1.5%) were found infected with T. foetus protozoa. Among these 3 positive cases of tritrichomoniasis, one was detected in aborted foetal materials and other two were detected in vaginal washings. We did not find any T. foetus in the semen samples from the bulls. Therefore, bulls represent zero prevalence of T. foetus. During the study period the examined animals were categorized into three age groups viz. 40, 60 and 100 cattle for below 3 years, over 3 years to below 6 years and over 6 years to ten years, respectively. The prevalence rate was found in adult cattle over 6 years (>610 years) was 2.00%, over 3 years (>36 years) was 1.66% and below 3 years (<3 years) was 0%. In the study, prevalence rate of cross bred animals were 2.22% and no infection was found in indigenous bred. So, this preliminary study indicates that a low prevalence rate of bovine trichomoniasis present in cattle in this study area. Further investigation using serological and molecular method will help to detect precisely the prevalence of this important sexually transmitted protozoan disease in cattle. To our best knowledge, this is the first study on the prevalence of bovine tritrichomoniasis in Bangladesh except a single clinical case reported in 1974. This study also indicate that bovine tritrichomoniasis has a minor role related to abortion of cattle in Bangladesh

In vivo sedative and hypnotic activities of methanol extract from the leaves of Jacquemontia paniculata (Burm.f.) Hallier f. in Swiss Albino mice.

BACKGROUND: The superior genus Jacquemontia belongs to Convolvulaceae, with around 120 species, and is also considered taxonomically difficult. The aim of this experiment was to assess the sedative and hypnotic activities of methanol extract from the leaves of Jacquemontia paniculata (Burm.f.) Hallier f. METHODS: The sedative and hypnotic activities were evaluated by hole-cross, open field, hole-board, elevated plus maze (EPM), and thiopental sodium-induced sleeping time determination tests in mice at doses of 200 and 400 mg/kg. RESULTS: In this investigation, we found that methanol extract of Jacquemontia paniculata (MEJP) produced a significant dose-dependent inhibition of spontaneous activity of mice both in hole-cross and open field tests. In addition, it also decreased the number of head dips in hole-board test. In the case of EPM test, this crude extract induced an anxiogenic-like effect rather than anxiolytic effect in mice. Moreover, MEJP significantly decreased the induction time to sleep and prolonged the duration of sleeping, induced by thiopental sodium. CONCLUSIONS: To conclude, these results suggest that the MEJP leaves possess potent sedative and hypnotic activities, which supported its therapeutic use for sleep disorders like insomnia

Axonal variant of Guillain-Barre syndrome associated with Campylobacter infection in Bangladesh

Background: Campylobacter jejuni enteritis is the predominant bacterial infection preceding Guillain-Barre syndrome (GBS), an acute postinfectious immune-mediated polyradiculoneuropathy. The purpose of this study was to define the clinical phenotype of GBS and the relation with preceding C jejuni infections in Bangladesh. Methods: We performed a prospective matched case-control hospital surveillance including 100 patients fulfilling the National Institute of Neurological Disorders and Stroke criteria for GBS from 2006 to 2007 in the Dhaka area of Bangladesh. Detailed clinical, electrophysiologic, serologic, and microbiologic data were obtained with a follow-up of 6 months. Results: GBS affected predominantly young adult males living in rural areas. Sixty-nine percent of the patients had clinical evidence of a preceding infection. The most frequent symptom was diarrhea (36%). The majority of patients had a pure motor variant of GBS (92%) with relatively infrequent cranial nerve involvement (30%). Twenty-five percent of patients required respiratory support. Electrophysiologic studies showed that 67% of patients had an axonal variant of GBS. Eleven patients (14%) died, and 23 (29%) remained severely disabled during the follow-up. Positive C jejuni serology was found in an unprecedented high frequency of 57% as compared with 8% in family controls and 3% in control patients with other neurologic diseases (p < 0.001). C jejuni infection was significantly associated with serum antibodies to the gangliosides GM1 and GD1a, axonal neuropathy, and greater disability. Conclusions: We report an unusually high frequency of the axonal variant of Guillain-Barre syndrome in Bangladesh, associated with preceding Campylobacter jejuni infection, severe residual disability, and high mortality. Neurology (R) 2010; 74: 581-58