Short‐term impact of COVID‐19 on consumption spending and its underlying mechanisms: Evidence from Singapore

Muscle disuse and denervation leads to muscle atrophy, but underlying mechanisms can be different. Previously, we have found ceramide (Cer) accumulation and lipid raft disruption after acute hindlimb suspension (HS), a model of muscle disuse. Herein, using biochemical and fluorescent approaches the influence of unilateral denervation itself and in combination with short-term HS on membrane-related parameters of rat soleus muscle was studied. Denervation increased immunoexpression of sphingomyelinase and Cer in plasmalemmal regions, but decreased Cer content in the raft fraction and enhanced lipid raft integrity. Preliminary denervation suppressed (1) HS-induced Cer accumulation in plasmalemmal regions, shown for both nonraft and raft-fractions; (2) HS-mediated decrease in lipid raft integrity. Similar to denervation, inhibition of the sciatic nerve afferents with capsaicin itself increased Cer plasmalemmal immunoexpression, but attenuated the membrane-related effects of HS. Finally, both denervation and capsaicin treatment increased immunoexpression of proapoptotic protein Bax and inhibited HS-driven increase in antiapoptotic protein Bcl-2. Thus, denervation can increase lipid raft formation and attenuate HS-induced alterations probably due to decrease of Cer levels in the raft fraction. The effects of denervation could be at least partially caused by the loss of afferentation. The study points to the importance of motor and afferent inputs in control of Cer distribution and thereby stability of lipid rafts in the junctional and extrajunctional membranes of the muscle.

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Abnormal auditory N400 in a case of zolpidem dependence, during a working memory test

European Psychiatry ◽

10.1016/j.eurpsy.2004.11.013 ◽

2006 ◽

Vol 21 (2) ◽

pp. 135-137 ◽

Cited By ~ 5

Author(s):

Ioannis A. Liappas ◽

Charalabos C. Papageorgiou ◽

Andreas D. Rabavilas

Keyword(s):

Working Memory ◽

Spatial Working Memory ◽

Event Related Potentials ◽

Short Term ◽

Context Processing ◽

Gaba A ◽

Related Potentials ◽

N400 Component ◽

Underlying Mechanisms ◽

Term Management

AbstractZolpidem is a GABA (A) agonist, which is indicated for the short-term management of insomnia. Recent research provide evidence suggesting that zolpidem produces spatial working memory (WM) deficits and dependence; however, the underlying mechanisms of these effects are unknown. Since the auditory N400 component of event-related potentials (ERPS) is considered as an index of memory use of context processing, the present study focused on N400 waveform of ERPs elicited during a WM task in a case suffering from zolpidem dependence. The patterns of N400 waveform of this case were compared to the patterns obtained from healthy controls. This comparison revealed that zolpidem dependence is accompanied by reduced amplitudes located at posterior brain areas and diffuse prolongation of N400. These findings may indicate that zolpidem dependence manifests alterations with regard to the memory use of context processing, involving or affecting a wide-ranging network of the brain's structures.

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Aquifer-eustasy as the main driver of short-term sea-level fluctuations during Cretaceous hothouse climate phases

Geological Society London Special Publications ◽

10.1144/sp498-2019-105 ◽

2019 ◽

Vol 498 (1) ◽

pp. 9-38 ◽

Cited By ~ 9

Author(s):

Benjamin Sames ◽

M. Wagreich ◽

C. P. Conrad ◽

S. Iqbal

Keyword(s):

Sea Level ◽

Phase Relationship ◽

Sea Level Changes ◽

Short Term ◽

Groundwater Levels ◽

Sequence Stratigraphic ◽

Sea Level Fluctuations ◽

Minimum Estimate ◽

Underlying Mechanisms ◽

Continental Ice Sheets

AbstractA review of short-term (<3 myr: c. 100 kyr to 2.4 myr) Cretaceous sea-level fluctuations of several tens of metres indicates recent fundamental progress in understanding the underlying mechanisms for eustasy, both in timing and in correlation. Cretaceous third- and fourth-order hothouse sea-level changes, the sequence-stratigraphic framework, are linked to Milankovitch-type climate cycles, especially the longer-period sequence-building bands of 405 kyr and 1.2 myr. In the absence of continental ice sheets during Cretaceous hothouse phases (e.g. Cenomanian–Turonian), growing evidence indicates groundwater-related sea-level cycles: (1) the existence of Milankovitch-type humid-arid climate oscillations, proven via intense humid weathering records during times of regression and sea-level lowstands; (2) missing or inverse relationships of sea-level and the marine δ18O archives, i.e. the lack of a pronounced positive excursion, cooling signal during sea-level lowstands; and (3) the anti-phase relationship of sea and lake levels, attesting to high groundwater levels and charged continental aquifers during sea-level lowstands. This substantiates the aquifer-eustasy hypothesis. Rates of aquifer-eustatic sea-level change remain hard to decipher; however, reconstructions range from a very conservative minimum estimate of 0.04 mm a−1 (longer time intervals) to 0.7 mm a−1 (shorter, probably asymmetric cycles). Remarkably, aquifer-eustasy is recognized as a significant component for the Anthropocene sea-level budget.

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A model of order-selectivity based on dynamic changes in the balance of excitation and inhibition produced by short-term synaptic plasticity

Journal of Neurophysiology ◽

10.1152/jn.00568.2014 ◽

2015 ◽

Vol 113 (2) ◽

pp. 509-523 ◽

Cited By ~ 14

Author(s):

Vishwa Goudar ◽

Dean V. Buonomano

Keyword(s):

Synaptic Plasticity ◽

Computational Models ◽

Experimental Studies ◽

Inhibitory Synapses ◽

Speech Discrimination ◽

Short Term ◽

Dynamic Changes ◽

Short Term Plasticity ◽

Underlying Mechanisms ◽

Parametric Analyses

Determining the order of sensory events separated by a few hundred milliseconds is critical to many forms of sensory processing, including vocalization and speech discrimination. Although many experimental studies have recorded from auditory order-sensitive and order-selective neurons, the underlying mechanisms are poorly understood. Here we demonstrate that universal properties of cortical synapses—short-term synaptic plasticity of excitatory and inhibitory synapses—are well suited for the generation of order-selective neural responses. Using computational models of canonical disynaptic circuits, we show that the dynamic changes in the balance of excitation and inhibition imposed by short-term plasticity lead to the generation of order-selective responses. Parametric analyses predict that among the forms of short-term plasticity expressed at excitatory-to-excitatory, excitatory-to-inhibitory, and inhibitory-to-excitatory synapses, the single most important contributor to order-selectivity is the paired-pulse depression of inhibitory postsynaptic potentials (IPSPs). A topographic model of the auditory cortex that incorporates short-term plasticity accounts for both context-dependent suppression and enhancement in response to paired tones. Together these results provide a framework to account for an important computational problem based on ubiquitous synaptic properties that did not yet have a clearly established computational function. Additionally, these studies suggest that disynaptic circuits represent a fundamental computational unit that is capable of processing both spatial and temporal information.

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Predictors of Supratentorial Deep Intracerebral Hemorrhage Volume and Their Effect on Short-Term Mortality in Asians

Cerebrovascular Diseases ◽

10.1159/000446552 ◽

2016 ◽

Vol 42 (5-6) ◽

pp. 319-331 ◽

Cited By ~ 4

Author(s):

Myung Hoon Han ◽

Jae Min Kim ◽

Hyeong-Joong Yi ◽

Jin Hwan Cheong ◽

Yong Ko ◽

...

Keyword(s):

Alcohol Consumption ◽

Intracerebral Hemorrhage ◽

Regression Line ◽

Normal Weight ◽

Short Term ◽

Risk Of Death ◽

Increased Risk ◽

Short Term Mortality ◽

Relevant Variables ◽

Underlying Mechanisms

Background: The volume of intracerebral hemorrhage (ICH) measured at hospital admission is the strongest predictor of clinical outcomes in patients with ICH. Despite the high incidence rate of ICH in Asians, there is lack of data regarding predictors of ICH volume in this ethnic group. The purpose of this study was to determine predictors of deep ICH volume and examine their effect on short-term mortality in Asians. Methods: Hematoma volume was measured using the ABC/2 method. ICH volume was transformed to the natural log scale to normalize distributions for all analyses. We estimated the coefficients of ICH volume based on relevant predictors using multivariable linear regression. We also determined the association between body mass index (BMI) and ICH volume using a regression line and a line determined by a locally weighted scatter plot smoothing. Results: A total of 1,039 patients from 2 twin hospitals in Korea who were admitted with primary spontaneous supratentorial deep ICH over a 12-year period were enrolled in this study. The median ICH volume was 19.7 ml. The average patient age was 59.2, and 62.4% of patients were men. The mean ICH volume showed a gradual, approximately 2% decrease per 1 BMI increase in the current study, after adjusting for all relevant variables (β = -0.024; SE 0.004; p < 0.001). In addition, patients with frequent alcohol consumption showed a 10% increase in mean ICH volume (β = 0.098; SE 0.041; p = 0.016), and patients undergoing warfarin treatment showed a 30% increase in mean ICH volume after full adjustment of all relevant variables (β = 0.296; SE 0.050; p < 0.001). Relative to overweight patients, there was a 47, 11, and 18% increase in admission mean ICH volume in underweight, normal weight and obese patients, respectively. Patients in the first quartile and underweight BMI groups had 1.45-fold (hazard ratio (HR) 1.45; 95% CI 1.03-2.03; p = 0.035) and 1.77-fold (HR 1.77; 95% CI 1.10-2.84; p = 0.019) higher increased risk of death during the first 3 months after ICH, retrospectively. In addition, patients in groups with frequent alcohol consumption and warfarin use both showed a significant association with mortality 90 days after ICH. Conclusions: We demonstrated the association between various predictors and admission ICH volume with short-term mortality in Asians. Further studies are needed to account for these observations and determine their underlying mechanisms.

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Ghrelin does not orchestrate the metabolic changes seen in fasting but has significant effects on lipid mobilisation and substrate utilisation

Acta Endocrinologica ◽

10.1530/eje-10-1122 ◽

2011 ◽

Vol 165 (1) ◽

pp. 45-55 ◽

Cited By ~ 8

Author(s):

M S B Huda ◽

T M Dovey ◽

S P Wong ◽

P J English ◽

J C G Halford ◽

...

Keyword(s):

Metabolic Response ◽

Ketone Bodies ◽

Controlled Study ◽

Morbidly Obese ◽

Metabolic Flexibility ◽

Short Term ◽

Substrate Utilisation ◽

Esterified Fatty Acids ◽

Obese Subjects ◽

Underlying Mechanisms

ObjectiveShort-term fasting is associated with increased GH pulsatility and mobilisation of fats, but underlying mechanisms are unclear. We studied ghrelin's role during fasting and the effects of exogenous ghrelin on lipid mobilisation.DesignRandomised placebo-controlled study.MethodsIn this study, ten controls (body mass index (BMI) 23.3±3.2), ten morbidly obese subjects (BMI 50.1±10.6) and six post-gastrectomy subjects (BMI 25.2±1.0) were fasted for 36 h undergoing regular blood sampling. On a separate occasion, subjects were infused with either i.v. ghrelin (5 pmol/kg per min) or saline over 270 min.ResultsObese and post-gastrectomy subjects had lower ghrelin compared with controls (ANOVA, P=0.02) during the fast. Controls and gastrectomy subjects showed a similar increase in GH pulsatility, circulating non-esterified fatty acids (NEFA) and 3β-hydroxybutyrate (3 HB). Obese subjects had an impaired GH response (P<0.001), reduced excursions of 3 HB (P=0.01) but no change in NEFA excursions (P=0.09) compared with controls. Ghrelin infusion increased GH, NEFA and ketone bodies (ANOVA, P<0.0001) in all the three groups, but GH response was impaired in the obese subjects (P=0.001). Ghrelin also induced a significant (ANOVA, P=0.004) biphasic NEFA response to meals in all the subjects.ConclusionsDespite low circulating ghrelin, gastrectomy subjects maintain a normal metabolic response to fasting, implying that ghrelin plays a minimal role. In contrast, infused ghrelin has significant effects on lipid mobilisation and induces a marked biphasic NEFA response to meals. Hence, ghrelin may play a significant role in meal-related substrate utilisation and metabolic flexibility.

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Functional synapse types via characterization of short-term synaptic plasticity

10.1101/648725 ◽

2019 ◽

Cited By ~ 3

Author(s):

Jung Hoon Lee ◽

Luke Campagnola ◽

Stephanie C. Seeman ◽

Tim Jarsky ◽

Stefan Mihalas

Keyword(s):

Large Scale ◽

Short Term ◽

Brain Science ◽

Short Term Plasticity ◽

Synaptic Physiology ◽

History Of ◽

Experimental Protocols ◽

Network Simulations ◽

Underlying Mechanisms

AbstractThe strengths of synaptic connections dynamically change depending on the history of synaptic events, which is referred to as short-term plasticity (STP). While STP’s underlying mechanisms are well researched, its exact functions remain poorly understood. This is in part due to the diverse patterns of STP experimentally reported. Recently, the Allen Institute for Brain Science has launched the synaptic physiology pipeline to characterize the diverse properties of synapses. Since this pipeline generates a large-scale survey of synapses in mouse primary visual cortex using highly standardized experimental protocols, it provides a unique opportunity to study diverse patterns of STP. Here, we develop an end-to-end workflow that can characterize STP from the Allen Institute for Brain Science pipeline data and conduct network simulations to infer STP’s functions. Employing this workflow, we find 1) that diverse patterns of STP exist even in the same synapse classes and 2) that postsynaptic neurons’ responses have distinct characteristics depending on STP.

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Language Exposure in Bilingual Toddlers: Performance on Nonword Repetition and Lexical Tasks

American Journal of Speech-Language Pathology ◽

10.1044/2015_ajslp-13-0106 ◽

2015 ◽

Vol 24 (2) ◽

pp. 126-138 ◽

Cited By ~ 8

Author(s):

Myrto Brandeker ◽

Elin Thordardottir

Keyword(s):

Vocabulary Knowledge ◽

Nonword Repetition ◽

Expressive Vocabulary ◽

Short Term ◽

Scoring Method ◽

English Only ◽

Complex Skill ◽

Language Exposure ◽

Underlying Mechanisms

Purpose The amount of language exposure is correlated with bilingual lexical development, but findings are mixed on how exposure relates to nonword repetition (NWR), a complex skill involving both short-term processing and long-term vocabulary knowledge. We extend previous work to a younger age group by investigating the role of exposure on NWR versus vocabulary, along with the effect of item construction and scoring. Method Sixty typically developing children (ages 2;5–3;6[years;months]) were assessed for NWR and receptive and expressive vocabulary. Participants ranged in amount of previous exposure to English and French from 0% to 100% and were tested in both languages if able to participate, even with very limited exposure (28 completed testing in both languages, 11 completed testing in English only, 21 completed testing in French only). Results Correlational analyses showed moderate to strong associations between the amount of exposure and vocabulary in that language, whereas the relationship of exposure with NWR was weak or nonsignificant, depending on scoring method. NWR correlated with vocabulary in English only. Performance on NWR was affected by nonword length but unaffected by wordlikeness. Conclusions NWR and vocabulary were differently related to language exposure. The underlying mechanisms of NWR at this age appeared mainly reliant on short-term processes, in contrast to long-term vocabulary knowledge.

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An integrated mathematical model of the human cardiopulmonary system: model development

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00230.2014 ◽

2016 ◽

Vol 310 (7) ◽

pp. H899-H921 ◽

Cited By ~ 25

Author(s):

Antonio Albanese ◽

Limei Cheng ◽

Mauro Ursino ◽

Nicolas W. Chbat

Keyword(s):

Neural Control ◽

Model Development ◽

Control Mechanisms ◽

Short Term ◽

Physiological Variables ◽

Animal Data ◽

Adult Humans ◽

Underlying Mechanisms ◽

Cardiopulmonary System ◽

Alveolar Gas Exchange

Several cardiovascular and pulmonary models have been proposed in the last few decades. However, very few have addressed the interactions between these two systems. Our group has developed an integrated cardiopulmonary model (CP Model) that mathematically describes the interactions between the cardiovascular and respiratory systems, along with their main short-term control mechanisms. The model has been compared with human and animal data taken from published literature. Due to the volume of the work, the paper is divided in two parts. The present paper is on model development and normophysiology, whereas the second is on the model's validation on hypoxic and hypercapnic conditions. The CP Model incorporates cardiovascular circulation, respiratory mechanics, tissue and alveolar gas exchange, as well as short-term neural control mechanisms acting on both the cardiovascular and the respiratory functions. The model is able to simulate physiological variables typically observed in adult humans under normal and pathological conditions and to explain the underlying mechanisms and dynamics.

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