Inhibitory effects of Melicope ptelefolia extract on compound action potentials in frog sciatic nerves and its possible mechanism of action

Melicope ptelefolia is a medicinal plant from the Rutaceae, also known as ‘tenggek burung’ in Malaysia. Traditionally, natives ingest M. ptelefolia to treat a wide range of illnesses. This study aimed to investigate the effects of M. ptelefolia aqueous extract (MPAE) on compound action potentials (CAPs) in frog sciatic nerves and its mechanism involving the opioid receptors. The effects of MPAE on CAPs in frog sciatic nerves were examined using the AD Instrument Nerve Chamber. The frog sciatic nerves were dissected from the lumbar plexus to the knee of the frog and placed in Ringer’s solution. Three treatment groups with different dosages (1, 3 and 10 mg/mL) of MPAE, including negative (vehicle) and positive control group (3 mg/mL of morphine) were tested on the frog sciatic nerves by placing them in a nerve organ chamber. Following this, the involvement of opioid receptors in the effects of MPAE on CAPs was investigated by using naloxone hydrochloride as a non-selective opioid receptor antagonist. Our results showed that the peak amplitudes of CAPs were significantly (p<0.001) reduced when treated with MPAE (3 and 10 mg/mL) in frog sciatic nerves. The MPAE-induced CAPs inhibition was reversed when pre-treated with naloxone, suggesting the involvement of the opioidergic system. These results indicated the modulatory action of MPAE on nerve conduction, which may provide important leads in the development of new therapeutic drugs through the involvement of opioid receptors

Boesenbergia rotunda ethanolic extract inhibits compound action potentials via opioid receptors

Boesenbergia rotunda, traditionally used to relieve stomach, abdomen, joint, muscle, and rheumatic pain was also reported for its antinociceptive effect on a mouse model. However, the possible pain relief effect of Boesenbergia rotunda ethanolic extract (BREE) via the inhibition to the neural pain pathway remains to be elucidated. This study investigated the inhibitory effect of BREE on compound action potentials (CAPs) and the possible involvement of the opioid receptors. The changes in the CAPs amplitudes of the frog’s sciatic nerves were evaluated following the exposure to three different dosages of BREE (1, 3 and 10 mg/ml and morphine (3 mg/ml). In another set of experiment, the nerves were pretreated with a non-selective opioid receptor antagonist, naloxone (0.1 mg/ml), before exposing the nerve to BREE (1 mg/ml) to investigate the involvement of opioid receptors in the CAPs inhibitory mechanism. The outcome showed a reduction in the CAPs amplitudes when treated with BREE (1, 3 and 10 mg/ml) whereby the effect was reversible. The CAPs inhibition by BREE was absent when the opioid receptors were blocked. Taken together, these findings suggest that BREE-induced CAPs amplitude reduction involves the activation of opioid receptors

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M&gt;70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0&lt;e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Universal methicillin-resistant Staphylococcus aureus (MRSA) screening: Comparison of anatomic screening sites for patients with high and low prevalence of MRSA carriage

10.1086/664042Infection Control and Hospital Epidemiology333315-317ICEP

Influenza Pandemics in Singapore, a Tropical, Globally Connected City

Tropical cities such as Singapore do not have well-defined influenza seasons but have not been spared from influenza pandemics. The 1918 epidemic in Singapore, which was then already a major global trading hub, occurred in 2 waves, June–July, and October–November, and resulted in >2,870 deaths. The excess mortality rate was higher than that for industrialized nations in the Northern Hemisphere but lower than that for less industrialized countries in Asia and Africa. The 1957 epidemic occurred in May and resulted in widespread illness. The 1968 epidemic occurred in August and lasted a few weeks, again with widespread illness. Tropical cities may be affected early in a pandemic and have higher mortality rates. With the increase in travel and trade, a future pandemic may reach a globally connected city early and spread worldwide. Preparedness and surveillance plans must be developed to include the megacities of the tropical world

Using the Johns Hopkins ACG Case-Mix System for population segmentation in a hospital-based adult patient population in Singapore

Objective Population health management involves risk characterisation and patient segmentation. Almost all population segmentation tools require comprehensive health information spanning the full care continuum. We assessed the utility of applying the ACG System as a population risk segmentation tool using only hospital data.Design Retrospective cohort study.Setting Tertiary hospital in central Singapore.Participants 100 000 randomly selected adult patients from 1 January to 31 December 2017.Intervention Hospital encounters, diagnoses codes and medications prescribed to the participants were used as input data to the ACG System.Primary and Secondary Outcome Measures Hospital costs, admission episodes and mortality of these patients in the subsequent year (2018) were used to assess the utility of ACG System outputs such as resource utilisation bands (RUBs) in stratifying patients and identifying high hospital care users.Results Patients placed in higher RUBs had higher prospective (2018) healthcare costs, and were more likely to have healthcare costs in the top five percentile, to have three or more hospital admissions, and to die in the subsequent year. A combination of RUBs and ACG System generated rank probability of high healthcare costs, age and gender that had good discriminatory ability for all three outcomes, with area under the receiver-operator characteristic curve (AUC) values of 0.827, 0.889 and 0.876, respectively. Application of machine learning methods improved AUCs marginally by about 0.02 in predicting the top five percentile of healthcare costs and death in the subsequent year.Conclusion A population stratification and risk prediction tool can be used to appropriately segment populations in a hospital patient population even with incomplete clinical data

Nephrinuria associates with multiple renal traits in type 2 diabetes

10.1093/ndt/gfq738Nephrology Dialysis Transplantation2682508-2514NDTR