The Impact of Cardiac Comorbidity Sequence at Baseline and Mortality Risk in Type 2 Diabetes Mellitus: A Retrospective Population-Based Cohort Study.

The presence of multiple comorbidities increases the risk of all-cause mortality, but the effects of the comorbidity sequence before the baseline date on mortality remain unexplored. This study investigated the relationship between coronary heart disease (CHD), atrial fibrillation (AF) and heart failure (HF) through their sequence of development and the effect on all-cause mortality risk in type 2 diabetes mellitus. This study included patients with type 2 diabetes mellitus prescribed antidiabetic/cardiovascular medications in public hospitals of Hong Kong between 1 January 2009 and 31 December 2009, with follow-up until death or 31 December 2019. The Cox regression was used to identify comorbidity sequences predicting all-cause mortality in patients with different medication subgroups. A total of 249,291 patients (age: 66.0 ± 12.4 years, 47.4% male) were included. At baseline, 7564, 10,900 and 25,589 patients had AF, HF and CHD, respectively. Over follow-up (3524 ± 1218 days), 85,870 patients died (mortality rate: 35.7 per 1000 person-years). Sulphonylurea users with CHD developing later and insulin users with CHD developing earlier in the disease course had lower mortality risks. Amongst insulin users with two of the three comorbidities, those with CHD with preceding AF (hazard ratio (HR): 3.06, 95% CI: [2.60-3.61], < 0.001) or HF (HR: 3.84 [3.47-4.24], < 0.001) had a higher mortality. In users of lipid-lowering agents with all three comorbidities, those with preceding AF had a higher risk of mortality (AF-CHD-HF: HR: 3.22, [2.24-4.61], < 0.001; AF-HF-CHD: HR: 3.71, [2.66-5.16], < 0.001). The sequence of comorbidity development affects the risk of all-cause mortality to varying degrees in diabetic patients on different antidiabetic/cardiovascular medications

Historical perspective and recent progress in cardiac ion channelopathies research and clinical practice in Hong Kong

Cardiac ion channelopathies encompass a set of inherited or acquired conditions that are due to dysfunction in ion channels or their associated proteins, typically in the presence of structurally normal hearts. They are associated with the development of ventricular arrhythmias and sudden cardiac death. The aim of this review is to provide a historical perspective and recent advances in the research of the cardiac ion channelopathies, Brugada syndrome, long QT syndrome and catecholaminergic polymorphic ventricular tachycardia, in Hong Kong, China. In particular, recent works on the development of novel predictive models incorporating machine learning techniques to improve risk stratification are outlined. The availability of linked records of affected patients with good longitudinal data in the public sector, together with multidisciplinary collaborations, implies that ion channelopathy research efforts have advanced significantly

Axonal Control of the Adult Neural Stem Cell Niche

SUMMARYThe ventricular-subventricular zone (V-SVZ) is an extensive germinal niche containing neural stem cells (NSC) in the walls of the lateral ventricles of the adult brain. How the adult brain’s neural activity influences the behavior of adult NSCs remains largely unknown. We show that serotonergic (5HT) axons originating from a small group of neurons in the raphe form an extensive plexus on most of the ventricular walls. Electron microscopy revealed intimate contacts between 5HT axons and NSCs (B1) or ependymal cells (E1) and these cells were labeled by a transsynaptic viral tracer injected into the raphe. B1 cells express the 5HT receptors 2C and 5A. Electrophysiology showed that activation of these receptors in B1 cells induced small inward currents. Intraventricular infusion of 5HT2C agonist or antagonist increased or decreased V-SVZ proliferation, respectively. These results indicate that supraependymal 5HT axons directly interact with NSCs to regulate neurogenesis via 5HT2C

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Morphogens and Axons in the Regulation of Adult Neural Stem Cells

Neural stem cells (NSCs) persisting in the walls of the lateral ventricles of the adult mammalian brain continue to produce new neurons and glia throughout life. The identification of NSCs, and long-range migration and integration of new neurons and glia into fully developed neural circuits suggest possible strategies for brain repair. Understanding the mechanisms that regulate adult neurogenesis will better enable us to harness the regenerative potential of NSCs for neuronal replacement. In this dissertation, I demonstrate an extensive plexus of supraependymal serotonergic (5HT) axons. These 5HT axons form intimate contacts with the apical domain of NSCs and likely regulate their proliferation via the 5HT2C receptor. Also on the apical domain of NSCs is a small, highly specialized organelle called the primary cilium, known for its role in signal transduction, but whose function in adult NSCs is unknown. I show that primary cilia are required for a unique population of progenitors in the ventral region of the ventricular-subventricular zone (V-SVZ), and that ablation of primary cilia disrupts Sonic hedgehog (Shh) signaling in these progenitors. Further, I identify a novel Shh-dependent domain in the dorsal V-SVZ, which generates not only olfactory bulb (OB) neurons, but also astrocytes and oligodendrocytes that migrate to the cortex and corpus callosum (CC). These new findings expand our knowledge on the endogenous mechanisms that control the NSC niche in the adult mammalian brain

Primary cilia are required in a unique subpopulation of neural progenitors.

The apical domain of embryonic (radial glia) and adult (B1 cells) neural stem cells (NSCs) contains a primary cilium. This organelle has been suggested to function as an antenna for the detection of morphogens or growth factors. In particular, primary cilia are essential for Hedgehog (Hh) signaling, which plays key roles in brain development. Their unique location facing the ventricular lumen suggests that primary cilia in NSCs could play an important role in reception of signals within the cerebrospinal fluid. Surprisingly, ablation of primary cilia using conditional alleles for genes essential for intraflagellar transport [kinesin family member 3A (Kif3a) and intraflagellar transport 88 (Ift88)] and Cre drivers that are activated at early [Nestin; embryonic day 10.5 (E10.5)] and late [human glial fibrillary acidic protein (hGFAP); E13.5] stages of mouse neural development resulted in no apparent developmental defects. Neurogenesis in the ventricular-subventricular zone (V-SVZ) shortly after birth was also largely unaffected, except for a restricted ventral domain previously known to be regulated by Hh signaling. However, Kif3a and Ift88 genetic ablation also disrupts ependymal cilia, resulting in hydrocephalus by postnatal day 4. To directly study the role of B1 cells' primary cilia without the confounding effects of hydrocephalus, we stereotaxically targeted elimination of Kif3a from a subpopulation of radial glia, which resulted in ablation of primary cilia in a subset of B1 cells. Again, this experiment resulted in decreased neurogenesis only in the ventral V-SVZ. Primary cilia ablation led to disruption of Hh signaling in this subdomain. We conclude that primary cilia are required in a specific Hh-regulated subregion of the postnatal V-SVZ