Increase In Lag Time Research Articles

The common VTE-protective G haplotype of F5 increases factor V-short, TFPI function, and risk of bleeding

AbstractThe G haplotype is a group of co-inherited single nucleotide variants in the F5 gene that reduce venous thromboembolism (VTE) risk. Although 7% of the population is homozygous for the G haplotype (F5-G/G), the underlying mechanism of VTE protection is poorly understood. Using RNA sequencing data from 4651 blood donors in the INTERVAL study, we detected a rare excision event at the factor V (FV)-short splice sites in 5% of F5-G/Gs carriers as compared with 2.16% of homozygotes for the F5 reference sequence (F5-ref; P = .003). Highly elevated (∼10-fold) FV-short, an FV isoform that lack most of the B-domain, has been linked with increased tissue factor inhibitor α (TFPIα) levels in rare hemorrhagic diathesis, including East Texas bleeding disorder. To ascertain whether the enhanced FV-short splicing seen in F5-G/G INTERVAL participants translated to increased plasma FV-short levels, we analyzed plasma samples from 7 F5-G/G and 13 F5-ref individuals in a recall-by-genotype study. A ∼2.2-fold higher amount of FV-short was found in a plasma pool from F5-G/G participants when compared with the pool of F5-refs (P = .029), but there was no difference in the total FV levels. Although no significant difference in TFPI levels were found, F5-G/Gs showed a ∼1.4-fold TFPI-dependent increase in lag time to thrombin generation than F5-refs (P = .0085). Finally, in an analysis of 117 699 UK Biobank participants, we discovered that, although being protective against VTE, the G haplotype also confers an increase in bleeding episodes (P = .011). Our study provides evidence that the effect of the common G haplotype is mediated by the FV-short/TFPI pathway.

Relationship Between High Frequency Component of Heart Rate Variability and Delta EEG Power During Sleep in Women With Irritable Bowel Syndrome Compared to Healthy Women.

To explore the relationship between the high frequency (HF) heart rate variability (HRV) and electroencephalogram (EEG) delta band power in women with irritable bowel syndrome (IBS) versus healthy control women. Twenty women with IBS and twenty healthy controls were studied over three consecutive nights using polysomnography in a sleep laboratory. To avoid the first night effect, only second-night data were analyzed. Power spectral analysis was applied to HRV and EEG recordings. The linear system coherence/phase analysis assessed the relationship between normalized HF power of HRV and normalized delta band power of EEG during the first four NREM-REM sleep cycles. Women with IBS exhibited a significantly higher percentage of NREM sleep, higher normalized HF, lower normalized low frequency (LF) and decreased LF/HF ratio of HRV in the first four NREM-REM sleep cycles compared to controls. Additionally, their normalized delta band power was significantly lower in these sleep cycles and over the whole night. The phase shift between HF and delta band power was significantly longer in the IBS group. While the coherence between normalized HF and normalized delta band power was lower in the IBS group, the difference was not statistically significant. The coherence/phase analysis showed a dysregulated interaction between autonomic and central nervous systems in women with IBS, manifested by increased lag time between cardiac and EEG delta band power compared to healthy controls. Whether this dysregulation contributes to the pathophysiology of IBS remains to be determined.

Rapid Emergence of Resistance to Broad-Spectrum Direct Antimicrobial Activity of Avibactam.

Avibactam (AVI) is a diazabicyclooctane (DBO) β-lactamase inhibitor used clinically in combination with ceftazidime. At concentrations higher than those typically achieved in vivo , it also has broad-spectrum direct antibacterial activity against Enterobacterales strains, including metallo-β-lactamase-producing isolates, mediated by inhibition of penicillin-binding protein 2 (PBP2). This activity is mechanistically similar to that of more potent novel DBOs (zidebactam, nacubactam) in late clinical development. We found that resistance to AVI emerged readily, with a mutation frequency of 2×10 -6 to 8×10 -5 . Whole genome sequencing of resistant isolates revealed a heterogeneous mutational target that permitted bacterial survival and replication despite PBP2 inhibition, in line with prior studies of PBP2-targeting drugs. While such mutations are believed to act by upregulating the bacterial stringent response, we found a similarly high mutation frequency in bacteria deficient in components of the stringent response, although we observed a different set of mutations in these strains. Although avibactam-resistant strains had increased lag time, suggesting a fitness cost that might render them less problematic in clinical infections, there was no statistically significant difference in growth rates between susceptible and resistant strains. The finding of rapid emergence of resistance to avibactam as the result of a large mutational target has important implications for novel DBOs with potent direct antibacterial activity, which are being developed with the goal of expanding cell wall-active treatment options for multidrug-resistant gram-negative infections but may be vulnerable to treatment-emergent resistance.

Clot lysis time and thrombin generation in patients undergoing transcatheter aortic valve implantation.

Aortic valve stenosis (AS) is the most prevalent valvular heart disease and is associated with a significant increase in mortality. AS has been shown to be linked with numerous coagulation system abnormalities, including increased fibrin deposition on the stenotic aortic valves. Transcatheter aortic valve implantation (TAVI) is the primary treatment method for patients at high surgical risk. The aim of the study was to assess the impact of treating severe AS with TAVI on thrombin generation and clot lysis time (CLT). We studied 135 symptomatic AS patients recommended for TAVI by the local Heart Team. All measurements were performed before and 5-7 days after TAVI. Alongside clinical assessment and echocardiographic analysis, we assessed clot lysis time (CLT) and thrombin generation parameters, including lag time, peak thrombin generation, time to peak thrombin generation (ttPeak), and endogenous thrombin potential (ETP). 70 patients were included in the final analysis. After TAVI, there was a significant 9% reduction in CLT despite a 12% increase in fibrinogen concentration. We observed significant increase in lag time and ttPeak (20% and 12%, respectively), and 13% decrease in peak thrombin concentration compared to pre-procedural levels. Multivariable linear regression analysis demonstrated that baseline CLT and C-reactive protein (CRP) levels were independent predictors of significant reduction in mean aortic gradient, defined as TAVI procedure success. CLT and peak thrombin concentration decreased, while Lag time and ttPeak increased significantly after TAVI. Multivariable linear regression analysis demonstrated CLT and CRP levels as independent predictors of achieving a reduction in mean aortic gradient, defining TAVI procedure success.

Catchment-Scale Hydrologic Effectiveness of Residential Rain Gardens: A Case Study in Columbia, Maryland, USA

To mitigate the adverse impacts of urban stormwater on streams, watershed managers are increasingly using low-impact development and green infrastructure (LID-GI) stormwater control measures, such as rain gardens—vegetated depressional areas that collect and infiltrate runoff from rooftops and driveways. Their catchment-scale performance, however, can vary widely, and few studies have investigated the cumulative performance of residential rain gardens for event runoff control in intermediate-sized (i.e., 1–10 km2) suburban catchments. We modeled three years of continuous rainfall-runoff from a 3.1 km2 catchment in Columbia, MD, USA, using the Storm Water Management Model (SWMM). Various extents of rain garden implementation at residential houses were simulated (i.e., 25%, 50%, 75%, and 100% coverage) to determine the effects on peak flow, runoff volume, and lag time. On average, treating 100% of residential rooftops in the catchment reduced peak flows by 14.3%, reduced runoff volumes by 11.4%, and increased lag times by 3.2% for the 223 rainfall events during the simulation period. Peak flow reductions were greater for smaller storm events (p < 0.01). Our results show that residential rain gardens can significantly improve the runoff response of suburban catchments, and that they represent an effective and relatively low-cost option for urban watershed management and restoration.

Bacteroides thetaiotaomicron metabolic activity decreases with polysaccharide molecular weight.

Polysaccharides are complex molecules that are commonly found in our diet. While humans lack the ability to degrade many polysaccharides, their intestinal microbiota contain bacterial commensals that are versatile polysaccharide utilizers. The gut commensal Bacteroides thetaiotaomicron dedicates roughly 20% of their genomes to the expression of polysaccharide utilization loci for the broad range utilization of polysaccharides. Although it is known that different polysaccharide utilization loci are dedicated to the degradation of specific polysaccharides with unique glycosidic linkages and monosaccharide compositions, it is often overlooked that specific polysaccharides may also exist in various molecular weights. These different physical attributes may impact their processability by starch utilization system-like systems, leading to differing growth rates and nutrient-sharing properties at the community level. Therefore, understanding how molecular weight impacts utilization by gut microbe may lead to the potential design of novel precision prebiotics.

Time-kill kinetics of Piper betle L. ethanolic leaf extract on methicillin-sensitive Staphylococcus aureus

Staphylococcus aureus is one of the main pathogens in community and hospital infections that could cause mild skin infections to severe life-threatening bacteremia. Piper betle has shown antibacterial activities against S. aureus but its pharmacodynamics remains unclear despite its widespread availability in many over-the-counter preparations. This study aimed to describe the time-kill kinetics of P. betle extract against methicillin-sensitive Staphylococcus aureus ATCC 29213 (MSSA). Time-kill kinetics were conducted to describe the killing rate of P. betle extract by its effects on MSSA lag time duration, growth rate, and maximum optical density. The surviving colonies at different time-points after exposure to P. betle extract at minimum bactericidal concentration were also determined. Subinhibitory concentrations elucidated its concentration-dependent antibacterial activity by maintaining a trend of increasing lag time, decreasing growth rate, and decreasing maximum optical density as the concentration increases. In particular, concentration at 1250 μg/mL or 0.5 x minimum inhibitory concentration (MIC) showed consistent significant findings across these parameters. Concentrations at MIC and above did not show growth, indicating MSSA growth inhibition or death. P. betle extract’s bactericidal effect started immediately within two (2) hours and was sustained until no growth was observed from the eighth hour and beyond. P. betle extract maintained antibacterial activities against MSSA at subinhibitory concentrations and has also exhibited immediate and sustained bactericidal effect at minimum bactericidal concentration (MBC).

Flagellar interference with plasmid uptake in biofilms: a joint experimental and modeling study.

Plasmid conjugation is a key facilitator of horizontal gene transfer (HGT), and plasmids encoding antibiotic resistance drive the increasing prevalence of antibiotic resistance. In natural, engineered, and clinical environments, bacteria often grow in protective biofilms. Therefore, a better understanding of plasmid transfer in biofilms is needed. Our aim was to investigate plasmid transfer in a biofilm-adapted wrinkly colony mutant of Xanthomonas retroflexus (XRw) with enhanced matrix production and reduced motility. We found that XRw biofilms had an increased uptake of the broad host-range IncP-1ϵ plasmid pKJK5 compared to the wild type (WT). Proteomics revealed fewer flagellar-associated proteins in XRw, suggesting that flagella were responsible for reducing plasmid uptake. This was confirmed by the higher plasmid uptake of non-flagellated fliM mutants of the X. retroflexus wrinkly mutant as well as the wild type. Moreover, testing several flagellar mutants of Pseudomonas putida suggested that the flagellar effect was more general. We identified seven mechanisms with the potential to explain the flagellar effect and simulated them in an individual-based model. Two mechanisms could thus be eliminated (increased distances between cells and increased lag times due to flagella). Another mechanism identified as viable in the modeling was eliminated by further experiments. The possibility of steric hindrance of pilus movement and binding by flagella, reducing the frequency of contact and thus plasmid uptake, proved viable, and the three other viable mechanisms had a reduced probability of plasmid transfer in common. Our findings highlight the important yet complex effects of flagella during bacterial conjugation in biofilms.IMPORTANCEBiofilms are the dominant form of microbial life and bacteria living in biofilms are markedly different from their planktonic counterparts, yet the impact of the biofilm lifestyle on horizontal gene transfer (HGT) is still poorly understood. Horizontal gene transfer by conjugative plasmids is a major driver in bacterial evolution and adaptation, as exemplified by the troubling spread of antibiotic resistance. To either limit or promote plasmid prevalence and dissemination, we need a better understanding of plasmid transfer between bacterial cells, especially in biofilms. Here, we identified a new factor impacting the transfer of plasmids, flagella, which are required for many types of bacterial motility. We show that their absence or altered activity can lead to enhanced plasmid uptake in two bacterial species, Xanthomonas retroflexus and Pseudomonas putida. Moreover, we demonstrate the utility of mathematical modeling to eliminate hypothetical mechanisms.

End-tidal carbon dioxide after sodium bicarbonate infusion during mechanical ventilation or ongoing cardiopulmonary resuscitation

PurposeEnd-tidal CO2 is used to monitor the ventilation status or hemodynamic efficacy during mechanical ventilation or cardiopulmonary resuscitation (CPR), and it may be affected by various factors including sodium bicarbonate administration. This study investigated changes in end-tidal CO2 after sodium bicarbonate administration. Materials and methodsThis single-center, prospective observational study included adult patients who received sodium bicarbonate during mechanical ventilation or CPR. End-tidal CO2 elevation was defined as an increase of ≥20% from the baseline end-tidal CO2 value. The time to initial increase (lag time, Tlag), time to peak (Tpeak), and duration of the end-tidal CO2 rise (Tduration) were compared between the patients with spontaneous circulation (SC group) and those with ongoing resuscitation (CPR group). ResultsThirty-three patients, (SC group, n = 25; CPR group, n = 8), were included. Compared with the baseline value, the median values of peak end-tidal CO2 after sodium bicarbonate injection increased by 100% (from 21 to 41 mmHg) in all patients, 89.5% (from 21 to 39 mmHg) in the SC group, and 160.2% (from 15 to 41 mmHg) in the CPR group. The median Tlag was 17 s (IQR: 12–21) and the median Tpeak was 35 s (IQR: 27–52). The median Tduration was 420 s (IQR: 90–639). The median Tlag, Tpeak, and Tduration were not significantly different between the groups. Tduration was associated with the amount of sodium bicarbonate for SC group (correlation coefficient: 0.531, p = 0.006). ConclusionThe administration of sodium bicarbonate may lead to a substantial increase in end-tidal CO2 for several minutes in patients with spontaneous circulation and in patients with ongoing CPR. After intravenous administration of sodium bicarbonate, the use of end-tidal CO2 pressure as a physiological indicator may be limited.

Impact of lag time on lung function impairment in pulmonary tuberculosis sequelae patients – A cross-sectional study

Background: Treatment completed pulmonary tuberculosis (PTB) patients are often left with permanent pulmonary function impairment. Lag time remains a major factor in determining the severity of the sequelae. Aims and Objectives: This study aims to assess the impact of lag time on PTB sequelae. Materials and Methods: A cross-sectional study was conducted during July 2019–December 2020. A total of 85 patients presenting with clinicoradiological features of PTB sequelae were recruited for the study and spirometry and diffusion capacity of lungs (DLCO) were done. They were divided into study groups based on lag time. The lag time (in days) was considered as primary explanatory variable. One-way ANOVA and Chi-square tests were used. coGuide V.1.0 was used for statistical analysis. Results: The mean lag time was 52.94 days in the study population. The mean duration of after treatment was 15.45 years in the study population. There was a statistically significant difference across study groups (classified based on the lag time) in lung function such as FVC%, FEV1, FEVI/FVC, MEF, DLCO, and duration of after treatment (P<0.05). Conclusion: The lag time from the development of symptom to the diagnosis of the disease has a significant impact on lung function impairment in PTB sequelae patients since the increase in lag time increases the severity of lung function impairment. Early identification and treatment may help in reducing the progression of lung function impairment.

Quantitative investigation on localized deformation process of rocks by uniaxial test and digital image correlation

Determining the localized deformation mechanism is of vital importance to understand the failure processes of geomaterials in practical engineering. In this study, uniaxial monotonic and cyclic loading tests of slate samples were conducted and the failure processes were recorded by using the AE system and digital image correlation (DIC). The results show that the deformation field variance increases significantly in the initiation of the macro-scale failure stage. Under cyclic loading, the shape of the stress-variance hysteresis curve varies with increasing upper limit stress, and four types of stress-variance hysteresis curves were revealed. Increasing lag time of variance indicates gradual accumulation of damage to the sample. The comprehensive analysis of the evolution process of damage variables defined by cumulative AE counts and variance reveals that the rock failure process can be divided into crack closure stage, initial damage stage, stable development stage, accelerated development stage and failure stage. By proposing the differentiation rate, it is found that there are apparent failure precursor points under monotonic and cyclic loading.

Evaluating the effectiveness of land use management as a natural flood management intervention in reducing the impact of flooding for an upland catchment

AbstractNatural flood management (NFM) is a method for reducing flooding by using a catchment‐based approach to managing flood risk. Understanding and quantifying the impact of implementing NFM at the catchment scale remains ambiguous with a clear need for robust empirical evidence. A combination of fieldwork, laboratory analysis and modelling was applied to quantify the impacts of land use management changes on catchment flood hazard. Soil hydraulic conductivity was measured under varying land management regimes and used to parameterize a physically based spatially distributed hydrological model (SD‐TOPMODEL). A suite of stakeholder informed land management scenarios was modelled, permitting the quantification of the impact of NFM interventions on the timing and the intensity of the peak discharge at the catchment outlet. The findings support the implementation of NFM interventions as a means of reducing flood hazard within a rural upland catchment. Improved soil infiltration provided the greatest reduction in the intensity and delayed timing of the flood peak for a 10‐year occurrence storm event (7% reduction in peak runoff and 8% increase in lag time) with similar reductions observed for a 100‐year storm event. Catchment wide woodland planting reduced peak flow by 11% during the 100‐year event but was not effective during the 10‐year event. Riparian buffer strips provided consistent reductions in peak flow and in the timing of the peak across both storm events with no significant differences relating to vegetation age. Critically, we observed that the effect of implementing multiple NFM interventions was not additive and that efficiencies can be made in using this modelling approach to prioritize the most effective outcomes.

Investigation of hydrometeorological influences on reservoir releases using explainable machine learning methods

Long short-term memory (LSTM) networks have demonstrated successful applications in accurately and efficiently predicting reservoir releases from hydrometeorological drivers including reservoir storage, inflow, precipitation, and temperature. However, due to its black-box nature and lack of process-based implementation, we are unsure whether LSTM makes good predictions for the right reasons. In this work, we use an explainable machine learning (ML) method, called SHapley Additive exPlanations (SHAP), to evaluate the variable importance and variable-wise temporal importance in the LSTM model prediction. In application to 30 reservoirs over the Upper Colorado River Basin, United States, we show that LSTM can accurately predict the reservoir releases with NSE ≥ 0.69 for all the considered reservoirs despite of their diverse storage sizes, functionality, elevations, etc. Additionally, SHAP indicates that storage and inflow are more influential than precipitation and temperature. Moreover, the storage and inflow show a relatively long-term influence on the release up to 7 days and this influence decreases as the lag time increases for most reservoirs. These findings from SHAP are consistent with our physical understanding. However, in a few reservoirs, SHAP gives some temporal importances that are difficult to interpret from a hydrological point of view, probably because of its ignorance of the variable interactions. SHAP is a useful tool for black-box ML model explanations, but the hydrological processes inferred from its results should be interpreted cautiously. More investigations of SHAP and its applications in hydrological modeling is needed and will be pursued in our future study.

Acclimatisation of Fusarium langsethiae, F. poae and F. sporotrichioides to elevated CO2: Impact on fungal growth and mycotoxin production on oat-based media

Oats are highly susceptible to infection by Fusarium species, especially F. langsethiae, F. poae and F. sporotrichioides which contaminate the grain with mycotoxins. Climate change is expected to affect fungal colonisation and associated mycotoxin production. The objective of this study was to examine the effect of acclimatisation to elevated CO2 on the growth and mycotoxin production capacity of these fungal species. Strains of F. langsethiae (FL; seven strains), F. poae (FP; two strains) and F. sporotrichioides (FS; one strain) were acclimatised by sub-culturing for 10 generations at either 400 or 1000 ppm CO2 under diurnal temperature conditions. At each sub-culturing, the effect of acclimatisation to elevated CO2 on (a) lag phase prior to growth, (b) growth rate on oat-based media was assessed. Additionally, the production of type A trichothecenes and related toxic secondary metabolites of sub-cultures after 1, 7 and 10 generations were assessed using LC-MS/MS qTRAP. The results showed that Fusarium strains had an increased lag time and growth rate in response to the combined effect of sub-culturing and elevated CO2 levels. T-2 + HT-2 production was affected by elevated CO2 in strain FL4 (7.1-fold increase) and a decrease in strain FL1 (2.0-fold decrease) at the first sub-culturing and FS (1.3-fold decrease) after 7 sub-cultures compared to ambient conditions. The effect of sub-culturing on T-2 + HT-2 production varied depending on the fungal strain. For strain FL4, significantly less T-2 + HT-2 toxins were produced after 10 generations (4.4-fold decrease) as compared to that under elevated CO2 conditions after one sub-culture, and no change was observed under ambient conditions. The FS strain showed significant stimulation of T-2 + HT-2 toxin production after 10 sub-cultured generations (1.1-fold increase) compared to the initial sub-culture of this strain under elevated CO2 conditions. The production of other toxic secondary metabolites was generally not impacted by elevated CO2 conditions or by sub-culture for 10 generations, with the exceptions of FL1 and FP1. FL1 produced significantly more neosolaniol after 10 generations, when compared to those after 1 and 7, regardless of the CO2 conditions. For FP1, elevated CO2 significantly triggered beauvericin production after an initial sub-culture when compared to ambient conditions at the same sub-culture stage (29-fold). FP1 acclimatisation to elevated CO2 led to a decrease of beauvericin production after 10 generations when compared to 1 (6-fold). In contrast, sub-culturing for 10 generations compared to 1 under ambient CO2 conditions resulted in an increase in this toxin (12-fold).

Cellulose nanofiber/deacetylated quaternary chitosan composite packaging film for growth inhibition of Listeria monocytogenes in raw salmon

Fully deacetylated quaternized chitosan (DQCTS) was prepared and used as functional fillers in the cellulose nanofiber (CNF)-based films. Field emission scanning electron microscopy (FE-SEM) showed that DQCTS was uniform in the CNF biofilms. The addition of DQCTS with the CNF films changed the surface color and hydrophobicity and significantly enhanced composite films' UV and visible light-blocking properties. Also, the CNF/DQCTS composite films had strong antibacterial activity against Listeria monocytogenes. Raw salmon packaged with the CNF/DQCTS5% film exhibited potent antimicrobial activity against L. monocytogenes, showing increased lag time for the growth with decreasing specific growth rate (SGR) and maximum population density (MPD) at 4 °C, 10 °C, and 15 °C. Using CNF/DQCTS composite film as active food packaging can potentially extend raw salmon's shelf life.

Lagged effect of the Pacific Decadal Oscillation on decadal variation in global land precipitation

<p>The Pacific Decadal Oscillation (PDO), as the leading mode of sea surface temperature (SST) in the North Pacific, modulates the global temperature and precipitation. While previous studies have shown a negative relationship between the global precipitation and the PDO, the time-delayed feature of this relationship remains underexplored. Here we investigate the lagged effect of the decadal variations in the PDO on the global land precipitation using cross-correlation at multiple scales. We find that there is a delayed response of precipitation to the PDO, with the regional correlation peaking at a certain delay and gradually decreasing with increasing lag time. We note the asymmetric impacts of the positive and negative PDO phases on precipitation. Seasonal analysis reveals that the PDO is related to land precipitation during the subsequent season relative to the rest of the year, with the highest correlation occurring in the boreal winter. The delay in response is likely due to the constant SST forcing of the PDO to the atmospheric circulation. This study highlights the lag duration of the PDO�Cprecipitation relationship, potentially enriching our understanding of this relationship and enhancing climate predictions on decadal timescales.</p>

Role of Glycogen Mobilization and Mitochondrial Bioenergetics in Platelet Function, Hemostasis, and Thrombosis

Platelets are one of the most metabolically active cells in the bloodstream. They show metabolic flexibility, switching between glycolysis and oxidative phosphorylation (OxPhos) depending on oxygen tension and the availability of substrates. Platelets also have metabolizable glycogen granules that contribute to the energy pool upon activation. Our goal was to investigate platelet energy metabolism under normal physiological conditions to better understand the relative roles of the major ATP-generating processes (glycolysis, OxPhos, and glycogenolysis). To address the role of glycogen, we used 2 glycogen phosphorylase inhibitors and tested their effects on standard platelet functions e.g., secretion, aggregation, clot contraction, and thrombus formation under shear. We also measured the glycogen levels in resting and activated platelets and the presence of inhibitors. Consistent with previous studies, glycogen was utilized when platelets are activated with a ~25% decrease upon thrombin-mediated activation. Both inhibitors blocked the use of glycogen and led to a 3-fold increase in glycogen compared to controls. These data suggest the active turnover of glycogen in platelets. Our inhibitor studies indicated that glycogen is dispensable for low-energy processes like aggregation but contributed to secretion, clot contraction, and thrombus formation under shear. The inhibition was rescued by either increasing external glucose or bypassing glycolysis with added pyruvate. This study shows that the glycogen granules are metabolically active and contribute to the energy pool upon platelet activation; this pool is important for high-energy platelet functions like clot contraction. Deletion of platelet glucose transporters (GLUT1 and GLUT3) revealed an essential role of glucose metabolism in hemostasis in vivo. Glucose can power platelets via glycolysis alone or in combination with OxPhos (in the mitochondria). We sought to probe the relative importance of platelet mitochondrial bioenergetics in hemostasis and thrombosis. Previously used mitochondrial inhibitors (antimycin, oligomycin) are toxic and cannot be used for in vivo studies, thus we developed two novel mouse models with altered mitochondrial function using a platelet-specific deletion of TFAM and QPC. TFAM (Transcription Factor A Mitochondrial), is essential for the maintenance, transcription, and translation of mitochondrial DNA. Its deletion is expected to disrupt platelet mitochondrial DNA, which encodes 13 subunits of OxPhos. QPC is a subunit of ubiquinol-cytochrome c reductase complex III. Its deletion is expected to disrupt Complex III, which is part of the platelet mitochondrial respiratory chain. We confirmed TFAM deletion using Western blot analysis. Using the Seahorse Analyzer, we confirmed that deleting TFAM disrupted platelet mitochondrial bioenergetics in both resting and thrombin-stimulated platelets as seen as a ~40% decrease in Oxygen Consumption Rate (OCR). We also observed a significant decrease in ATP production indicating the contribution of OxPhos to ATP generation. Aggregation was not affected but in vitro clot contraction and thrombus formation under shear were defective (~58% increase in lag time, ~30% increase in AUC, and ~60% decrease in surface area coverage). Both the KO animals showed an increased tail-bleeding time, an increased occlusion time in the FeCl3 carotid injury model, and delayed hemostasis in a jugular puncture injury model with significantly higher rebleeding indicating that mitochondrial bioenergetics is important for clot stability. Using two novel mouse models with dysfunctional mitochondrial bioenergetics, we show that OxPhos is dispensable for low-energy demanding platelet functions such as aggregation but is important for secretion, clot contraction, hemostasis, and thrombosis (Table 1). Platelets show considerable plasticity in energy metabolism using both glycolysis and oxidative phosphorylation. Using mouse models and inhibitors, we show the relative importance of these energy-producing processes and the fuels and metabolic pathway choices made by platelets at different functional stages. Improving our understanding of platelet metabolism and the relative contributions of each pathway in the future could lead to a better understanding of how metabolic disorders can affect thrombotic risk in diabetic and obese patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Dietary anthocyanins inhibit insulin fibril formation and cytotoxicity in 3T3-L1 preadipocytes

Insulin fibril formation decreases the effectiveness of insulin therapy and causes amyloidosis in diabetes. Studies suggest that phytochemicals are capable of inhibiting fibril formation. Herein, we investigated the inhibitory effects of anthocyanins, including cyanidin, cyanidin-3-glucoside (C3G), cyanidin-3-rutinoside (C3R), malvidin, and malvidin-3-glucoside (M3G) on fibril formation. Our results revealed that anthocyanins (50–200 μM) significantly reduced the formation of insulin fibrils by increasing lag times and decreasing ThT fluorescence at the plateau phase. These findings were confirmed by TEM images, which showed reduced fibril length and number. Furthermore, FTIR analysis indicated that anthocyanins reduced the secondary structure transition of insulin from α-helix to β-sheet. Anthocyanins interacted with monomeric insulin (residues B8–B30) via H-bonds, van der Waals, and hydrophobic interactions, covering the fibril-prone segments of insulin (residues B12–B17). Based on the structure-activity analysis, the presence of glycosides and hydroxyl groups on phenyl rings increased intermolecular interaction, mediating the inhibitory effect of anthocyanins on fibril formation in the order of malvidin < cyanidin < M3G < C3G < C3R. Moreover, anthocyanins formed H-bonds with preformed insulin fibrils, except for malvidin. In preadipocytes, C3R, C3G, and cyanidin attenuated insulin fibril-induced cytotoxicity. In conclusion, anthocyanins are effective inhibitors of insulin fibril formation and cytotoxicity.

Association between Thrombin Generation and Clinical Characteristics in COVID-19 Patients

Introduction: Coronavirus disease 2019 (COVID-19) disease is associated with coagulopathy and an increased risk of thrombosis. An association between thrombin generation (TG) capacity, disease severity, and outcomes has not been well described. Methods: We assessed the correlation of TG with sequential organ failure assessment (SOFA) and sepsis-induced coagulopathy (SIC) scores and clinical outcomes by analysis of plasma samples obtained from hospitalized COVID-19 patients. Results: 32 patients (68.8% male), whose median age was 69 years, were assessed, of whom only 3 patients did not receive anticoagulant therapy. D-dimers were uniformly increased. During hospitalization, 2 patients suffered thrombosis, 3 experienced bleeding, and 12 died. TG parameters from anticoagulated COVID-19 patients did not significantly differ from the values obtained from non-anticoagulated healthy controls. Patients who received higher than prophylactic doses of anticoagulant therapy had increased lag time (p = 0.003), lower endogenous thrombin potential (ETP) (p = 0.037), and a reduced peak height (p = 0.006). ETP correlated with the SIC score (p = 0.038). None of the TG parameters correlated with the SOFA score or were associated with mortality. Conclusion: TG was not associated with disease severity among patients hospitalized with COVID-19. However, a correlation between ETP and the SIC score was noted and deserves attention.

Response of Runoff to Meteorological Factors Based on Time-Varying Parameter Vector Autoregressive Model with Stochastic Volatility in Arid and Semi-Arid Area of Weihe River Basin

This study explores the response characteristics of runoff to the variability of meteorological factors. A modified vector autoregressive (VAR) model is proposed by combining time-varying parameters (TVP) and stochastic volatility (SV). Markov chain Monte Carlo (MCMC) is used to estimate parameters. The TVP-SV-VAR model of daily runoff response to the variability of meteorological factors is established and applied to the daily runoff series from the Linjiacun hydrological station, Shaanxi Province, China. It is found that the posterior estimates of the stochastic volatility of the four variables fluctuate significantly with time, and the variance fluctuations of runoff and precipitation have strong synchronicity. The simultaneous impact of precipitation and evaporation on the pulse of runoff is close to 0. Runoff has a positive impulse response to precipitation, which decreases as the lag time increases, and a negative impulse response to temperature and evaporation with fluctuation. The response speed is precipitation &gt; evaporation &gt; temperature. The TVP-SV-VAR model avoids the hypothesis of homoscedasticity of variance and allows the variance to be randomly variable, which significantly improves the analysis performance. It provides theoretical support for the study of runoff response and water resource management under the conditions of climate change.