bluuebunny/crossref_metadata_2025_split huggingface dataset:
Digestion and fermentation of 13C labelled barley: a curve fitting approach
Authors: Priebe Marion G , Wang Hongwei , Weening Desirée , Jonkers Elles , Small Alexandra , Preston Tom , Vonk Roel J 
Published: June 2021

Information about the extent of starch digestion and fermentation, is critical to our ability to explore in vivo the effects of colonic fermentation of resistant starch present in a normal food matrix. We aimed to estimate with a curve fitting approach the extent of digestion and fermentation of starch in cooked barley kernels.Seventeen volunteers (21.1±1.3 years; mean±SD) ingested 86 g (dry weight) of cooked naturally 13C enriched barley kernels after an overnight fast. 13CO2 and H2 in breath samples were measured every 30 minutes for 12 h. The time point of rise in H2 above baseline was regarded as start of the fermentation process. Breath 13CO2 data before this point were used to fit the curve representing the digestion phase. The difference between the area under the curve (AUC) of the fitted digestion curve and the AUC of the observed curve was regarded to represent the fermentation part.Four hours after intake of barley, H2‐excretion in breath started to rise. Within 12 hours, 34.4±6.1% of the total 13C‐dose was recovered as 13CO2, of which 11.7±6.9% was derived from colonic fermentation and 88.3% from digestion. By extrapolating the curve to baseline it was estimated that eventually 14.3% of the total recovered 13C in barley would be derived from fermentation.Curve fitting, using data of breath 13CO2 and H2, could be a feasible and non‐invasive method to evaluate digestion and fermentation of starchy foods rich in resistant starch.
Male rats fed low or high carbohydrate diets for ten days did not differ in hepatic gene expression of enzymes associated with carbohydrate metabolism, but differed in peripheral insulin signaling
Authors: Moulton Christopher , Walker Denise , Yudell Barbara , Devkota Suzanne , Nakamura Manabu , Layman Donald 
Published: June 2021

Our laboratory previously reported differential metabolic regulations in rats and humans fed low or high carbohydrate diets designed to meet DRI guidelines for macronutrients. This study examined the impact of short‐term feeding of low vs. high carbohydrate diets (LC vs. HC) on gene expression of liver enzymes involved in carbohydrate metabolism and insulin signaling in skeletal muscle and adipose. LC and HC diets consisted of 42:30:28 (carbohydrate:protein:fat as % energy) and 60:12:28, respectively. Male SD rats ~250 g were fed 3 times/d to mimic human meal patterns. After 10 d, samples were obtained at fasted (n=8) or 90 min after a 4 g meal (n=8). Plasma insulin, glucagon, glucose, and triacylglyceride were not different in fasted samples. Liver gene expression of PEPCK, pyruvate kinase, glucose‐6‐phosphatase, and fatty acid synthetase was not different between diets. Insulin and triacylglyceride increased 97% (P<0.05) and 123% (P<0.10) after the HC meal, respectively, but increased only 51% (P<0.10) and 52% (P<0.10) after the LC meal. In skeletal muscle, LC caused greater activation (p=0.01) of Akt and p70S6K (p<0.05), while HC activated Akt (p<0.05) in adipose. In summary, short‐term feeding of LC and HC diets elicited no differences in hepatic gene expression of enzymes for carbohydrate metabolism, but produced differential insulin signaling in skeletal muscle and adipose.Support: Unigen Pharmaceutical
Role of the mammalian Target of Rapamycin (mTOR) Complex 1 signaling in beta‐adrenergic‐stimulated triacylglycerol (TAG) lipolysis and free fatty acid (FFA) release in 3T3‐L1 adipocytes
Authors: Soliman Ghada A. , Fingar Diane C. 
Published: June 2021

mTOR is a Ser/Thr kinase that integrates metabolic signals and is found in two complexes, a rapamycin‐sensitive complex (mTORC1) and a rapamycin‐insensitive complex (mTORC2). We have shown that rapamycin (RAPA) induces hypertriglyceridemia in transplant patients and increases FFA in guinea pigs. Therefore, we investigated a role for mTORC1 signaling in control of TAG metabolism.Using 3T3‐L1 adipocytes, we found that RAPA reduces cellular TAG content (2 fold p<0.05). To elucidate the mechanisms, we determined whether RAPA increases lipolytic rates. Thus we treated 3T3‐L1 adipocytes with Isoproterenol (Iso), a β‐adrenergic agonist that activates cAMP‐dependent Protein Kinase A (PKA), in the absence or presence of RAPA. We find that RAPA enhances Iso‐induced lipolysis, as measured by FFA release (p<0.01), but has no effect on cAMP levels. RAPA increases the phosphorylation of hormone sensitive lipase (HSL) on Ser 563, a site phosphorylated by PKA. RAPA also augments Iso‐mediated phosphorylation of perilipin (a protein that coats TAG droplet whose phosphorylation is critical for lipolysis,) which co‐immunoprecipitated with HSL and adipose triglyceride lipase. These data suggest that RAPA leads to increased lipolysis due to synergism with the β‐adrenergic‐PKA pathway. Moreover, these data may reveal a novel role for mTORC1 signaling in the regulation of FFA metabolism (Supported by AHA 0750060Z and K01 DK60654 to GS).
PINK1 suppresses 6‐OHDA‐mediated autophagic stress in the neuroblastoma SH‐SY5Y cell line
Authors: Dagda Ruben Karim , Kulich Scott , Chu Charleen 
Published: June 2021

PTEN‐induced kinase 1 (PINK1), is a mitochondrially targeted neuroprotective serine/threonine kinase whose mutation has been linked to PARK6 autosomal recessive parkinsonism. We have previously shown that 6‐hydroxydopamine (6‐OHDA) elicits mitochondrial reactive oxygen species (ROS) production which leads to neurodegeneration in vitro (Kulich et al, 2007).Using several cell survival assays, we show that transient or stable expression of wild‐type PINK1 (PINK1‐WT) in SH‐SY5Y cells partially protects against 6‐OHDA toxicity while transient expression of a kinase‐dead PINK1 mutant (PINK1‐KD) increases 6‐OHDA mediated cell death. Here, we report a set of molecular mechanisms by which PINK1 protects against 6‐OHDA. First, quantification of MitoSOX fluorescence showed that stable expression of PINK1‐WT suppresses 6‐OHDA mediated generation of mitochondrial superoxide. Moreover, stable expression of PINK1‐W.T. increases mitochondrial interconnectivity and blocks 6‐OHDA induced autophagic degradation of mitochondria while transient expression of PINK‐KD had the opposite effect as assessed by confocal microscopy. Thus our data support a model by which PINK1 prevents 6‐OHDA induced autophagic stress by blocking mitochondrial autophagy, increasing mitochondrial interconnectivity and suppressing 6‐OHDA induced production of mitochondrial ROS.
Characterization of Skeletal Muscle in Osteogenesis Imperfecta Model Mice
Authors: Weber Bettina Anne , Phillips Charlotte L. , Carleton Stephanie M , McCambridge Amanda , Timm David , Ning Jie , Ferreira J Andries , Brown Marybeth 
Published: June 2021

Osteogenesis imperfecta (OI), a heritable connective tissue disorder due to mutations in type I procollagen genes, results in bone deformity and fragility. OI model mice (oim) are homozygous for a null mutation in the COL1A2 gene and have significantly reduced bone biomechanical integrity and bone mineral density. Mice heterozygous for the mutation (oim/+) have a phenotype intermediate to that of homozygous (oim/oim) and wild type (+/+) mice. OI patients report reduced muscle capacity and strength, although no systematic evaluation of muscle function and pathology in humans or animal models of OI has been performed. We characterized muscle mass, fiber morphology and contractile generating capacity of oim and oim/+ mice to determine whether muscle weakness is inherent to the disease or due to inactivity. We demonstrated that the contractile generating capacity of hindlimb muscles is not impaired in oim/+ and oim/oim mice relative to +/+ mice; and that muscle cross sectional area and mass/body mass ratios are similar between genotypes, suggesting that oim/+ and oim/oim mice do not have inherent muscle pathology.NIH/T32 RR0007004‐29, MO Res Brd, Leda J Sears Trust Fdn.
Trace amine‐associated receptor 1 (TAAR1) modulates dopaminergic activity
Authors: Hoener Marius Christian , Lindemann Lothar , Meyer Claas Aiko , Jeanneau Karine , Bradaia Amyaouch , Ozmen Laurence , Bettler Bernhard , Wettstein Joseph G , Borroni Edilio , Moreau Jean‐Luc 
Published: June 2021

The recent identification of the trace amine associated receptor 1 (TAAR1) provides an opportunity to dissociate the effects of trace amines on the dopamine transporter from receptor‐mediated effects. In order to separate both effects on a physiological level, a Taar1‐deficient mouse line was generated.Taar1‐deficient mice displayed increased sensitivity to amphetamine as revealed by enhanced amphetamine‐triggered increases in locomotor activity and augmented striatal release of dopamine as compared to wild‐type animals. Under baseline conditions, locomotion as well as extracellular striatal dopamine levels were similar between Taar1 knock‐out and wild‐type mice. Electrophysiological recordings revealed an elevated spontaneous firing rate of dopaminergic neurons in the ventral tegmental area of Taar1 knock‐out mice. The endogenous TAAR1 agonist p‐tyramine specifically decreased the spike frequency of these neurons in wild‐type but not in Taar1 knock‐out mice, consistent with the prominent expression of Taar1 in the ventral tegmental area.Taken together, the data reveal TAAR1 as regulator of dopaminergic neurotransmission.
IMPACT OF ADVANCING AGE ON CAFFEINE MEDIATED SENSITIZATION OF CALCIUM RELEASE IN SUPERIOR CERVICAL GANGLION CELLS.
Authors: Behringer Erik J , Vanterpool Conwin K , Pearce William J , Buchholz John N 
Published: June 2021

In vascular sympathetic neurons calcium‐induced calcium release (CICR) is mediated by ryanodine receptors (RyR) and contributes to the magnitude of stimulation‐evoked intracellular calcium ([Ca2+]i) transients. Furthermore, this process can be sensitized with RyR agonists such as caffeine. In this study we assessed the contribution of CICR to the magnitude of electric field stimulation (EFS)‐evoked [Ca2+]i transients. We measured EFS‐evoked changes in [Ca2+]i in isolated fura‐2 loaded superior cervical ganglion (SCG) cells, from F‐344 rats aged 6, 12, and 24 months. EFS was delivered over a range of 3 to 24 pulses (3Hz) in the absence and presence of 5mM caffeine. Maximal EFS‐evoked increases in [Ca2+]i significantly increased from 6‐12 months and then declined at 24 months, suggesting that CICR as a component of the EFS‐evoked [Ca2+]i transient declines with age. However, most interestingly, caffeine significantly increased EFS‐evoked [Ca2+]i transients over the entire stimulation range (3–24 pulses) in all age groups. In addition, caffeine decreased the number of pulses to achieve ½ maximal EFS‐evoked [Ca2+]i in all age groups. Taken together, the data suggest that with advancing age although the contribution of CICR to EFS‐evoked [Ca2+]i transients may decline with age, some of this function can be reclaimed in the presence of RyR agonists such as caffeine.Supported in part by NIH HED P01 #31226
Active metabolite of vitamin D acutely reduces endothelium‐dependent contractions in the isolated SHR aorta
Authors: Wong Michael SK , Man Ricky YK , Vanhoutte Paul M 
Published: June 2021

Recent studies proved that vitamin D has cardiovascular effects besides regulating calcium homeostasis.Objectives:To study the effect of calcitriol (1,25‐dihydroxyvitamin D3) on endothelium‐dependent responses of the aorta of spontaneously hypertensive rats (SHR).Methods:Rings of aortae were suspended in organ chambers for isometric force measurement. Agonist‐induced endothelium‐dependent and independent responses as well as prostacyclin release were measured in the absence or presence of calcitriol. Cytosolic calcium concentration was monitored by confocal microscopy after incubation with fluorescent dyes, Fluo‐4 and Fura‐red.Results:Acetylcholine‐induced relaxation was not affected by administration of calcitriol while the acetylcholine‐ and ATP‐induced endothelium‐dependent contractions were reduced compared to those obtained in the absence of the drug. This effect was not present if the calcium ionophore A23187 was used as agonist. Acetylcholine‐ but not A23187‐induced release of prostacylin was reduced by acute administration of calcitriol. Exposure to calcitriol reduced the increase in cytosolic free calcium concentration caused by acetylcholine in the endothelial cells.Conclusions:This study shows that calcitriol can modulate vascular tone by reducing the release of endothelium‐derived contracting factor(s). (Partly supported by the CeDAR Foundation)
Inhibition of sphingosine kinase induces vasoconstriction in isolated carotid arteries obtained from spontaneous hypertensive but not normotensive rats
Authors: Spijkers Leon , Mathy Marie‐Jeanne , Michel Martin , Alewijnse Astrid , Peters Stephan 
Published: June 2021

Ceramide, sphingosine and sphingosine‐1‐phosphate (S1P) are signaling molecules generated from membrane phospholipids by a concerted action of several enzymes. These sphingomyelin metabolites (SM) have growth regulating properties; while S1P is implicated in growth stimulation, ceramide and sphingosine (the precursors of S1P) induce apoptosis. In addition, SM have vasoactive properties. For instance S1P, synthesized by sphingosine kinase, can increase NO production in endothelial cells and thereby induce vasodilation. Hypertension is a disease state characterized by endothelial dysfunction (decreased NO bioavailability) and vascular growth (remodeling). Therefore we investigated whether hypertension alters the vasoactive properties of locally produced SM. Inhibition of sphingosine kinase by means of dimethylsphingosine (DMS, 10 μM) induced a biphasic and transient contraction in isolated rat carotid arteries from spontaneous hypertensive but not normotensive animals. This contraction was endothelium and eicosanoid‐dependent since removal of the endothelium and inhibition of cyclooxygenase completely prevented DMS‐induced constriction. Alterations in sphingolipid metabolism may thus contribute to a disturbed regulation of vascular tone during hypertension.This research was performed within the framework of project T2‐108 of the Dutch Top Institute Pharma.
Systemic oxidative stress induced by Diabetes and Residual Oil Fly Ash Inhalation
Authors: Rhoden Claudia Ramos , Chagas Juliana K , Venturini Carina Duarte , Moresco Mauricio , Halmenschlager Graziele , Schmid Helena 
Published: June 2021

The importance of evaluating the systemic effects of diabetic subjects exposed to air pollution is notorious, specially to the relevance that both factors have in the world socio‐economic scenario. The aim of the present study is to evaluate the effects of diabetes and chronic exposure to “residual oil fly ash” (ROFA) in the rat systemic oxidative stress. The animals were divided into four groups: diabetic: treated with ROFA (DM POL) − 50μg of ROFA/10μL of saline, intranasal instillation (i.n.); diabetic (DM NPOL) ‐ 10μL of saline, i.n; non‐diabetic treated with ROFA (ND POL) − 50μg of ROFA/10μL of saline, i.n. and non‐diabetic (ND NPOL) ‐ 10μL of saline, i.n., for 60 days. The diabetes was induced by 60mg/kg, i.p. streptozotocin administration. Blood sample was collected on the 30º and 60° days of treatment to evaluate SOD and catalase activity and the lipid peroxidation (through the concentration of malondialdeyde ‐MDA‐). After 30 days, we observed that ND POL animals showed higher levels of SOD comparing to the other groups (p<0.05) while catalase and MDA concentration did not show difference among the groups. After 60 days, the diabetic groups (DM POL and DM NPOL) showed increased levels of MDA. SOD activity was not statistically different among the groups (p> 0.05) while catalase showed statistically increased in the DM POL, DM NPOL and ND POL groups as compared to the control group ND NPOL (p<0.05). The global mortality rate of the DM POL group was 46% while in the other groups this rate was 0%. All deaths occurred after the 30° day of treatment with ROFA. The present study suggests that diabetic condition increases the susceptibility of health adverse effects induced by ROFA instillation and that oxidants could be involved in these effects.Support: FFFCMPA
Variability in valproic acid (VPA) metabolite signatures in children
Authors: Leeder James Steven , Gaedigk Andrea , Pearce Robin E. , Abbott Frank S. , Chang Thomas K.H. , Kiang Tony , Teng XiaoWei , Kennedy Mary Jayne , Ward Robert M. 
Published: June 2021

VPA is associated with an idiosyncratic hepatotoxicity that is most prevalent in children under 2 years of age receiving concurrent enzyme‐inducing anti‐epileptic drugs. The goal of this study was to establish the limits of normal variability in VPA metabolite patterns in a population of children. Urine was collected over a steady state dosing interval in 91 pediatric patients aged 2 to 17 years receiving VPA either as monotherapy or polytherapy, and analyzed by GC‐MS methods for VPA and 14 metabolites. Principal components analysis of the log‐transformed metabolite data (corrected for urinary creatinine) revealed three distinct clusters of metabolites generally corresponding to microsomal biotransformation, mitochondrial beta‐oxidation, and N‐acetylcysteine (NAC) metabolites derived from glutathione (GSH)‐conjugates of (E)‐2,4‐diene. If NAC conjugates are the products of reactive metabolite formation and GSH conjugation in mitochondria and free 2,4‐diene‐VPA is derived from a non‐reactive microsomal pathway, we hypothesize that the NAC‐VPA/2,4‐diene ratio may reflect interindividual variability in bioactivation and detoxification capacity. A Q‐Q plot of the log‐transformed ratio implies a bimodal distribution that is being evaluated as a potential biomarker for VPA‐toxicity in this population.Supported by grant U01 HD‐044239 from NICHD
Glutamate supplementation prevents Helicobacter pylori‐induced gastric mucosal damages in gerbils
Authors: Nakamura Eiji , Amagase Kikuko , Hasumura Mai , Gabriel Ana San , Uneyama Hisayuki , Torii Kunio , Takeuchi Koji 
Published: June 2021

Backgrounds & Aims: Chronic Helicobacter pylori (HP) infection induces gastric diseases such as gastritis, gastric ulcers and gastric cancers. The importance of urease‐derived ammonia in the pathogenesis of HP‐induced gastric diseases is known by the fact that Helicobacter felis (expresses urease but not vac A or cag PAI‐related gene products) induces gastritis and gastric cancer in animal models. Glutamate is previously reported to protect cultured gastric epithelial cells against ammonia (Am J Physiol 2002). However, whether glutamate protects in vivo gastric mucosa against HP is still unknown. Thus, we examined the effect of glutamate supplementation on HPi‐induced gastric mucosal damage using gerbil model.Materials & Methods: The diets with or without glutamate supplementation were fed to HPi‐infected Mongolian gerbils for 3 months, then the gastric mucosa were used for the macroscopic, histochemical analyses. The number of viable HP in the stomach was also determined.Results & Discussion: Glutamate supplementation significantly suppressed HP‐induced gastric mucosal damage and inflammatory cell infiltration. Interestingly, the number of viable HP in the stomach was unchanged between the diet with and without glutamate.Conclusion: Glutamate supplementation protects HP‐induced gastric mucosal damage without affecting HP itself, suggesting the stimulatory role of glutamate on gastric defensive factors.
Different Role of Calcium‐activated Potassium Channels in Human Internal Mammary (IMA) and Radial Artery (RA)
Authors: Fan Li , Xiao Xiao‐Qiu , Grove Kevin , Yang Qin , Furnary Anthony , He Guo‐Wei 
Published: June 2021

We investigated the contribution of small (SKCa) and intermediate conductance calcium‐activated potassium channel (IKCa) in human IMA and RA. Cumulative concentration (−10 ~ −5.5 log M)‐relaxation curves for acetylcholine (ACh) were established in IMA and RA rings (n=6) pretreated with/without inhibitor of SKCa (apamin, 100 nM) or IKCa (charybdotoxin, ChTX, 100 nM). Expression levels of SKCa and IKCa in the whole tissue and smooth muscle cells (SMC) of IMA and RA were quantitated with real‐time PCR. The relaxation curve to ACh was depressed significantly (p < 0.001) by apamin (29.5 ± 2.9% vs. control 55.5 ± 4.2%) and less by ChTX (44.0 ± 5.2%, p < 0.001) in IMA. In RA, the inhibition of apamin was less significant (57.1 ± 5.4%, p < 0.05) than ChTX (42.5 ± 8.2 % vs control 67.8 ± 8.9 %, p < 0.001). RT‐PCR showed that expression of SKCa was similar to IKCa in integrated IMA tissues (2.32 ± 0.20 vs. 2.24 ± 0.24, p=0.6), but higher than IKCa in IMA SMC (4.06 ± 0.60 vs 1.30 ± 0.26, p < 0.01). For RA, expression of SKCa was higher than IKCa (3.34 ± 0.44 vs 2.49 ± 0.57, p < 0.05) in both integrated tissue and SMC (30.27 ± 7.86 vs. 1.92 ± 0.58, p < 0.001). Thus, both SKCa and IKCa paly a role in IMA and RA. However, the mRNA expression of these ion channels is different in the endothelium and SMC between IMA and RA.Supported by St. Vincent Foundation, Hong Kong RGC (CUHK4383/03M) & CUHK (4450171, 4450231, 2041305).
The calsequestrin mutation CASQ2‐K206N affects sarcoplasmic reticulum Ca handling and causes catecholaminergic polymorphic ventricular tachycardia
Authors: Kirchhefer Uwe , Wehrmeister Diana , Müller Frank U. , Postma Alex V. , Schmitz Wilhelm , Neumann Joachim 
Published: June 2021

Catecholamine‐induced polymorphic ventricular tachycardia (CPVT) is a familial disorder caused by calsequestrin 2 (CASQ2) gene mutations. Here, we report the identification of a new CASQ2 mutation, K206N, which transmitted autosomally and is associated with CPVT and sudden cardiac death in a young patient. To find a causal link between K206N and the CPVT phenotype, we studied biochemical and physiological effects of K206N overexpression, in comparison to the native form (NT) of the calsequestrin protein (CSQ), in both insect cells and isolated neonatal mouse myocytes by use of recombinant baculoviruses and adenoviruses, respectively. The CSQ mutation was associated with the insertion of a second glycosylation site resulting in a higher mobility form compared to NT. Consistently, the mutated CSQ colocalized with mannosidase II, whereas NT did not. Thus, hyperglycosylation of K206N may trigger the lower Ca binding (by 54%) observed in 45Ca overlay blots. Moreover, we found a higher binding (by 40%) of the mutated CSQ to a GST‐triadin fusion protein in pull‐down assays. [3H]ryanodine binding was increased by 115% in homogenates of myocytes infected with K206N compared to NT, suggesting a higher open probability of the SR Ca release channel. In line with these findings, myocytes with K206N overexpression had a higher rate of spontaneous Ca transients, when exposed to isoproterenol.The data of the present study demonstrate that overexpression of K206N in myocytes causes an abnormal Ca handling and therefore, may predispose to the CPVT phenotype observed in the human patient.This study was supported by the Deutsche Forschungsgemeinschaft (Ki 653/13‐1/2).