bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vascular endothelial growth factor (VEGF) receptors expresion and VEGF–mediated permeability of human amnion to calcium in chorioamnionitis (ChA)
Authors: Szukiewicz Dariusz , Maslinska Danuta , Stangret Aleksandra , Klimkiewicz Jakub , Pyzlak Michal 
Published: June 2021

VEGF is a mediator of inflammation and an angiogenic factor. VEGF receptor type 1 (VEGFR1) regulates vascular permeability, while VEGFR2 is necessary for proliferation during the process of angiogenesis. ChA may change neovasculatization and permeability of placental membranes. We examined expression of VEGFR1 and VEGFR2 within amniotic epithelial cells and VEGF–mediated permeability of human amnion to calcium ions in ChA. 16 pieces of isolated extraplacental amnion obtained after near to term pregnancies complicated by ChA were compared with 16 gestationally matched amnion samples from normal pregnancies (Group I and II, respectively). Expression of VEGFR1 and VEGFR2 within amniotic epithelium was examined in calibrated areas of immunostained paraffin sections using morphometry for quantitative analysis. Diffusion of Ca++ was measured using a system of plastic container divided into two chambers by the mounted amnion. The effect of VEGF administration (doses range: 100–500 pg/ml) on the transport coefficient for Ca++ was examined in both groups. Expression of VEGFR1 was significantly increased in Group I and was positively correlated with increased VEGF‐mediated amnion permeability for Ca++ (p < 0.05). Our results indicate important influence of proinflammatory cytokine VEGF on calcium‐dependent biological phenomena, including preterm myometrial contractionsSupported by AM grant: 2M2‐W2‐07.
Bowel Mucosa Lymphoid Tissue in Experimental DMH Administration
Authors: Cabrita Antonio Silverio , Farinha Rodrigo , Rafael Ana Isabel , Matos‐Beja Manuel Correia 
Published: June 2021

The colon lamina propria is rich in lymphatic noduli (LN), which can occasionally become more proeminent in the mucosa. This can be caused by numerous stimuli. This work reports the changes found in the lymphoid tissue nodulae at the bowel mucosa level.We used 60 Wistar male rats randomly distributed in three groups of twenty animals each: group I, kept with no manipulation; group II submitted to the administration of 15mg DMH/Kg twice a week during 8 weeks, after which were sacrificed; group III submitted to the administration of the same toxic and concentration, for 8 weeks, sacrificed 4 weeks after the last administration. The intestine was collected for histology. By morphometry we evaluated the percentage of each lymphatic nodule that is present in the mucosa area.In the control group we didn't find LN occuping the mucosa area. In group II the LN area, for a 95% confidence interval varies between 211.1 and 234.7, and the percentage of LN area in the mucosa varies between 28.9% and 30.2%. The presence of LNs in the mucosa was 15% of the animals. In group III the LN area, for a 95% confidence interval varies between 236.1 and 290.1, and the percentage of LN area in the mucosa varies between varies between 24.7% and 28.8%. The presence of LNs in the mucosa was 35% of the animals.According to these findings, this carcinogen increased the bowel lymphoid tissue present in the mucosa.
A prothrombogenic phenotype is exhibited in sickle cell transgenic mice
Authors: Gavins Felicity Nicola , Granger Neil D. , Buckingham Julia C. 
Published: June 2021

Sickle cell disease (SCD) is a chronic genetic and lifelong disease, affecting the vasculature of different organs (1). This study, investigated the effects of SCD on thrombus formation.Intravital microscopy was performed in the cerebral microcirculation of wild‐type (WT), sickle cell transgenic (SCD; ƒÒs) and WT/ƒÒs chimeric (positive control) mice (as previously described: 1). Thrombus formation was formed using the light/dye model in arterioles and venules. Flow cessation time was recorded.Thrombus formation was reduced by 50% in SCD mice vs. WT in venules and arterioles. However, no difference was seen in WT/ƒÒs chimeric mice, suggesting the SCD mice response was not due to how they were generated.The clinical implication of anti‐coagulant therapy in SCD mice was investigated. Both Hirudin and anti‐thrombin III were administered. Although Hirudin increased the time required for thrombus formation, the anti‐thrombin III inhibitor was more effective in SCD venules, suggesting thrombus formation is effected via thrombin, but is dependent upon the anti‐thrombin III pathway in venules.These data further support the growing evidence for a pro‐inflammatory and pro‐thrombogenic microcirculation in SCD mice, which may lead to the identification of potential therapeutic targets in this painful and life‐threatening disease.Supported by the BBSRC
Control of integrin‐mediated platelet adhesion by rigidity sensing at the surface of fibrin(ogen) matrix
Authors: Podolnikova Nataly P. , Bowen Benjamin , Lishko Valeriy , Podolnikov Andriy , Ugarova Tatiana 
Published: June 2021

Recent evidence suggests that substrate rigidity controls cell adhesion through integrin‐mediated signaling. We have found that binding of soluble fibrinogen to the surface of insoluble fibrin matrix inhibits integrin‐mediated cell adhesion by creating an anti‐adhesive fibrinogen layer. To gain understanding of the mechanism underlying the differential ability of cells to adhere to the naked fibrin gel (rigid substrate) and to the loose fibrinogen layer formed on the surface of fibrin (soft substrate), we examined integrin αIIbβ3‐mediated signaling in platelets. Platelet adhesion to fibrin clots induced strong phosphorylation of FAK and Syk kinases as compared to adhesion on soft substrates. Also, the rigid, but not soft substrate induced recruitment of signaling molecules talin and skelemin to integrin‐containing focal adhesions. Consistent with their limited ability to induce sufficient signaling, soft substrates do not support platelet spreading. Differential platelet signaling was also observed when fibrinogen was adsorbed on plastic at low and high densities, a condition which mimics rigid and soft substrates, respectively. These data suggest that soluble fibrinogen prevents stable platelet adhesion to the fibrin clot by modifying its mechanical properties which results in insufficient signaling and reduced force generation.NIH HL 63199
PTX‐insensitive Gz transduction pathway contributes to buprenorphine‐induced supraspinal, but not spinal, antinociception
Authors: DING ZHE , RAFFA ROBERT B 
Published: June 2021

Buprenorphine is known as an opioid analgesic. Although it shares some of the general characteristics of other opioids, it displays preclinical pharmacology and clinical attributes distinct from opioids such as morphine and fentanyl. As a way of elucidating some of the differences, we investigated the contribution of G proteins in buprenorphine‐induced antinociception. Subcutaneous administration of buprenorphine, morphine or fentanyl induced antinociception in the warm‐water (48¡ãC) tail‐dip/flick test in mice in a dose‐related manner. The antinociception induced by all three agonists was attenuated by intrathecal (i.t.) administration of either pertussis toxin (PTX) (1 mg, 48h) or the opioid receptor antagonist naloxone (20 mg). However, intracerebroventricular (i.c.v.) PTX or naloxone administered attenuated only morphine‐ and fentanyl‐induced antinociception. Pretreatment with Gz antisense (14.6 mg, 24 h) i.t. had no effect on any agonist‐induced antinociception. However, pretreatment with Gz antisense (but not control) i.c.v. inhibited buprenorphine‐induced, but not morphine‐ or fentanyl‐induced antinociception. These results reveal that a PTX‐insensitive, Gz transduction pathway plays an important role in buprenorphine‐induced supraspinal antinociception distinct from, or to a greater degree than, morphine or fentanyl.This work was supported by Grünenthal GmbH (Germany).
Understanding receptor selectivity and ligand stereochemistry of insecticides and therapeutic agents for nicotinic acetylcholine receptor subtypes
Authors: Yamauchi John , Talley Todd , Park John , Tomizawa Motohiro , Casida John , Harel Michal , Taylor Palmer 
Published: June 2021

Neonicotinoids are insecticides selective for nicotinic acetylcholine receptors (nAChRs) in agricultural pests having a far lower affinity for vertebrate receptors. Additional understanding for the basis of receptor selectivity with the nAChRs is crucial for ascertaining whether insecticides are responsible for the bee “colony collapse disorder” or other toxicities in insect populations. Moreover receptor selectivity is integral to improved efficacy of new nicotinic therapeutic agents. The acetylcholine binding protein (AChBP), through mutagenesis modifications, can serve as a template for design of new therapeutic agents and insecticides. Its chief advantage stems from its solubility, making complexes amenable to crystallography and physical studies. Ligand dissociation constants were determined for steriosomers with radio‐ligand binding assays, using [3H]‐Epibatidine competing for purified Aplysia or Lymnaea AChBP sites. We have obtained evidence that stereochemistry in alkaloid, nicotinoid, and neonicotinoid ligands results in substantial differences of binding affinity to specific AChBPs. These data will be compared with crystallographic data to ascertain determinants essential for agonist and antagonist selectivity.Support from (R37‐GM18360, F32 NS043063, R01 ES08424, GM07752‐29)
Benzo[a]pyrene sensitizes mouse aortic endothelial cells to oxidized lipids
Authors: Jules George , Zhou LiChun , Yang Hong , Guo ZhongMao 
Published: June 2021

Benzo[a]pyrene (BaP) is a ubiquitous environmental pollutant arising from the incomplete combustion of organic substances, and is known to cause many diseases including atherosclerosis. It has also been shown that BaP activates phospholipase A2, an enzyme necessary for the synthesis of lysophosphatidylcholine (LPC), an oxidized lipid known to promote atherosclerosis. Several studies have shown that both LPC and BaP promote endothelial cell (EC) death through the production of reactive oxygen species such as hydrogen peroxide, a relatively stable molecule. However, the mechanism by which both LPC and BaP promote EC death is not well defined. Preliminary data from our laboratory shows that BaP increases sensitivity of mouse aortic endothelial cell (MAECs) to LPC. Therefore the central hypothesis to be tested in this study is that BaP increases lysophosphatidylcholine (LPC) induced cell death in mouse aortic endothelial cells (MAECs) through the production of reactive oxygen species such as hydrogen peroxide.To test this hypothesis, cell viability, membrane integrity, and apoptotic cell markers will be measured in MAECs obtained from wild‐type mice and mice overexpressing the human catalase gene (hCatTg+/0). Furthermore, phospholipase A2 enzyme activity will be examined in hCatTg+/0 and wild‐type ECs based on protein level, and the phosphorylation status of the protein. Since catalase is an antioxidant that converts H2O2 to water and oxygen, I expect to find cell death as well as phospholipase A2 activity to be decreased in hCatTg+/0 ECs compared to wild‐type cells.
Lercanidipine (LER) improves the endothelial dysfunction and prevents the vascular remodeling in diabetic rats
Authors: Martinez Márcio Luís Lombardi , Fernandes Karla , Bendhack Lusiane Maria , Tanus‐Santos José Eduardo 
Published: June 2021

Objective: We investigated whether pretreatment with LER affects the vascular reactivity to Acethylcoline (Ach) and prevents the vascular remodeling in Diabetic rats.Methods: Male Wistar rats (180–200 g) were used in this study. Insulin‐dependent diabetes was induced (alloxan 40 mg/kg), whereas in the control animals was injected vehicle only.LER (2,5 mg/kg/day) was added daily to drinking water, starting 3 weeks after induction of diabetes and maintained for additional six weeks. The animals of this study were divided into four groups as follows: control (C); (b) treated control (CL); diabetic (D); treated diabetic (DL). Measures of arterial pressure (SBP – tail cuff method) and experiments of vascular reactivity, gelatin zymography and quantitative RT‐PCR were performed.Results: SBP was increased in D group, and the treatment with LER attenuated the SBP in DL group. In the same way, LER restored the vascular reactivity to Ach in DL group. Moreover, increased MMP‐2 activity and expression was found in the aortas of D group, and LER reduced the MMP‐2 activity in DL group. In addition, an increase in the ratio of MMP‐2/TIMP‐2 mRNA expression was found in D group, whereas this ratio was reduced in DL group.Conclusion: Our results show that LER produces antihypertensive effects and reverses, at least in part, the vascular changes associated with diabetes in rats.Financial support: FAPESP‐CAPES‐CNPq
Ranolazine Attenuates Palmitoyl‐L‐Carnitine Induced Ventricular Diastolic Dysfunction
Authors: Wu Yuzhi , Belardinelli Luiz , Shryock John 
Published: June 2021

Background: Palmitoyl‐L‐carnitine (PC), an ischemic metabolite, increases late Na+ channel current, causing cellular Na+ and Ca2+ overload and contractile dysfunction. Ranolazine (Ran) is a selective blocker of late sodium current. This study was conducted to determine whether Ran attenuates PC‐induced diastolic dysfunction.Methods: Guinea pig isolated hearts perfused at constant flow (Langendorff method) were used to study left ventricular end‐diastolic pressure (LVEDP), coronary perfusion pressure (CPP), ventricular wall stiffness, and cardiac lactate and adenosine release. Hearts were treated with 4 μM PC for 30 min followed by treatment with Ran or vehicle for 30 min.Results: PC significantly increased LVEDP, CPP, wall stiffness, and lactate and adenosine release. Ran (10 μM) significantly attenuated the PC‐induced increase in LVEDP by 61 ± 5 % (n=6, p<0.001), the PC‐induced increase of CPP by 27 ± 3% (n=6–7, p<0.05), and the PC‐induced increases of lactate and adenosine release by 50 ± 7 and 75 ± 4 %, respectively (n=6, p ≤0.05 for both). Ran reduced the PC‐induced increase of wall stiffness: LVEDP at all intraventricular volumes was lower in the presence of Ran + PC than in the presence of PC alone.Conclusion: Ran attenuated PC‐induced ventricular diastolic dysfunction, as indicated by reductions of LVEDP, ischemic metabolites, and CPP.
Cardiac‐specific overexpression of P2X4 receptors enhanced myocyte contractility in the calsequestrin (CSQ) model of cardiomyopathy
Authors: Shen Jian‐Bing , Shutt Robin H , Pappano Achilles J , Liang Bruce T 
Published: June 2021

Overexpression of the human P2X4 purinoceptor (P2X4R) rescues the heart failure phenotype in the calsequestrin(CSQ)‐overexpressing transgenic (TG) model of cardiomyopathy (Am J Physiol 287:H1096, 2004). The objective is to study the contractility of binary P2X4R/CSQ (Binary) TG myocyte by comparing contraction shortening (CS) in ventricular myocytes. Cell length (102±1.8 μm vs. 108±2.3 μm, SE) and basal CS (5.3%±0.45% vs. 5.4%±0.38% of cell length, SE) at 0.2Hz pacing (22ºC) were similar in WT (N=41) vs. P2X4R myocytes (N=59). Cell length in Binary (151±1.6μm, N=54) was shorter than that in CSQ (158±2.1μm, N=60, p<0.05), indicating less hypertrophy. Basal CS in Binary (4.1±0.23 %) was greater than that in CSQ (2.6±0.20 %, p<0.02). At 2.0 Hz, basal CS was also greater in Binary (2.0±0.14%, N=30) than in CSQ (0.9±0.11 %, N=23, P<0.05) cells. With 3μM 2me‐SATP, CS increased significantly in myocytes from all four genotypes but the CS increases in P2X4R and Binary TG cells were greater than those in WT and CSQ cells respectively (P<0.05).Conclusion:Overexpression of the P2X4R in the CSQ model of cardiomyopathy caused enhanced myocyte contractility to agonist as well as increased basal myocyte contractility; the latter may be due to activation of the overexpressed P2X4R by endogenous extracellular ATP in vivo. Enhanced contractility may mediate the heart failure rescuing effect of P2X4R overexpression.
Inactivation of HCN channels slows rhythm differently in atria and ventricle and improves conduction in the anoxic‐reoxygenated embryonic chick heart
Authors: Gardier Stephany , Sarre Alexandre , Raddatz Eric 
Published: June 2021

Hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels control heart rate and are expressed early during cardiogenesis. Distribution of the predominant HCN4 isoform and the involvement of HCN channels in myocardial dysfunction induced by anoxia‐reoxygenation were investigated in the embryonic heart.Expression of HCN4 channels was determined by western blotting in atria (A), ventricle (V) and outflow tract (OT) from hearts of 4‐day‐old chick embryos. Hearts or isolated ventricles were exposed to the selective inhibitor of HCN channels ivabradine. Effects of 0.3μM ivabradine on ECG, excitation‐contraction (EC) coupling and contractility were determined in hearts submitted to 30 min anoxia and 60 min reoxygenation.The distribution of HCN4 was inhomogeneous, i.e. A ≥ V ≫ OT. The intrinsic rate was 164±22 in A and 78±24 bpm in isolated V. Under normoxia, 0.3 μM ivabradine decreased A rate by 20% and V rate by 50% and increased A‐V conduction by 20%. These effects persisted throughout anoxia‐reoxygenation, whereas variations of QT duration, EC coupling, contractility and arrhythmias were not affected.These data indicate that HCN channels are inhomogeneously distributed and control finely atrial and ventricular pacemakers of the embryonic heart. Their inactivation during anoxia‐reoxygenation ameliorates atrial rhythmicity and conduction.Supported by Servier and SNSF n°3100A0‐105901
Alpha 1A‐Adrenergic Receptor Signaling Protects the Heart From Ischemic Injury Through an ERK‐Dependent Mechanism
Authors: Rorabaugh Boyd R , Handel Evelyn M , Waterson Rachael E , Talbot Jeffery N , Perez Dianne M 
Published: June 2021

Brief periods of ischemia stimulate an endogenous mechanism in the heart that protects the myocardium from subsequent episodes of prolonged ischemia. This process, called “ischemic preconditioning”, is mimicked by signaling through α1A‐adrenergic receptors (ARs). Extracellular regulated kinases (ERK‐1 and ERK‐2) have been implicated in ischemic preconditioning. Therefore, we used mice expressing constitutively active mutant α1A‐adrenergic receptors (CAM α1A‐ARs) to determine whether α1A‐ARs protect the heart from ischemic injury through an ERK‐dependent mechanism. Western blots demonstrated that phosphorylation of ERK‐1 and ERK‐2 is significantly increased in CAM α1A‐AR hearts relative to nontransgenic hearts. Isolated hearts were perfused using the Langendorf method, and contractile function was monitored by an intraventricular balloon. Hearts isolated from CAM α1A‐AR or nontransgenic mice were subjected to 30 min ischemia and 1 hour reperfusion. Contractile function of CAM α1A‐AR hearts, but not nontransgenic hearts, completely recovered from 30 min ischemia. Perfusion with U0126 (MEK inhibitor) prior to the onset of ischemia blocked ERK phosphorylation and abolished the ability of CAM α1A‐AR hearts to recover from ischemia. These data support the conclusion that α1A‐ARs protect the heart from ischemic injury through an ERK‐dependent signaling pathway.(This study was supported by a Bower, Bennet, & Bennet Endowed Research Chair Award from Ohio Northern University).
Liver X Receptor alpha Gene Polymorphisms and Simvastatin Therapy
Authors: Alzahrani Sarah A. , Dzimiri Nduna 
Published: June 2021

Liver X receptor alpha subtype gene (LXRα) is involved in the regulation of cholesterol (Chol) metabolism and lipid biosynthesis, and may be downregulated by statins. The objective of this study was to investigate the prevalence and effect of two single nucleotide polymorphisms (SNPs), rs326220 and rs7934351, of the LXRα gene on patient responses to simvastatin therapy. Compared to 192 angiographic controls, the heterozygote C/T of the rs326220 was slight greater in patients (n =159) than in controls (5% vs 2.6%). Carriers of the homozygous C/C genotype in patients (151) exhibited greater reduction in total Chol (5.03 ± 0.11 pre vs 4.50 ± 0.10 post; p < 0.001) compared to the heterozygote C/T carriers (5.56 ± 0.37 vs 4.95 ± 0.44; p < 0.3) following 6 months treatment with 20mg/day simvastatin. Similar results were observed for low density lipoprotein (LDL) responses (p < 0.001 for C/C vs p < 0.07 for C/T). Interestingly, for the rs7934351, the homozygote A/A (2.5%) was present only in patients. The reduction in Chol (p < 0.001 vs p < 0.8) and LDL (p < 0.001 vs p < 0.9) was significantly greater in the heterozygote A/G (155) than in the A/A (4) carriers. Our results suggest that the heterozygote C/T of the rs326220 and homozygote A/A of the rs7934351are associated with lack of response to simvastatin therapy.Funding: The King Abdulaziz City for Science and Technology and King Faisal Specialist Hospital & Research Centre
Biochemical and structural properties of four CYP1B1 mutations present in primary congenital glaucoma (PCG) patients
Authors: choudhary Dharamainder , Jansson Ingela , Sarfarazi Mansoor , Schenkman John B 
Published: June 2021

Methods: The study involves heterologous protein expression of four mutant CYP1B1 forms (Y81N, E229K, A330F, R368H) in E. coli, analyzing their stability and ability to metabolize the endogenous substrates, estradiol, arachidonic acid and retinoids.Results: PCG is a major cause of childhood blindness and occurs due to an abnormal development of the trabecular meshwork (TM) and anterior chamber region of the eye. Our group was the first to link mutations in the CYP1B1 gene to the PCG phenotype. The role of CYP1B1 in eye development may involve its oxidative metabolic activity, whereby it could either generate or degrade an active signaling molecule, e.g. a morphogen, which affects the downstream transcriptional expression of genes associated with proper eye development. The data showed a high degree of instability for the Y81N and E229K mutant proteins. All the four mutants affected the metabolic activity significantly. The results were correlated with the structural changes in the CYP1B1 protein due to amino acid substitutions, based upon CYP1A2 crystal structure.Conclusion: The findings suggest that altered enzymatic properties of the CYP1B1 mutants towards endogenous substrates may be the cause of impaired eye development and the PCG phenotype.(Support: NIH grants R01 EY11095, 5R03 EY014654; American Health Assistance Foundation award AHAF G2007‐036)
Effects of Antioxidants on Contracting Spinotrapezius Muscle Force Production and Oxygen Consumption in Aged (26–30 Month Old) Rats
Authors: Herspring Kyle F , Ferreira Leorando F , Copp Steven W , Poole David C , Musch Timothy I 
Published: June 2021

Aged rats exhibit a decreased muscle microvascular O2 partial pressure (PO2mv) at rest and during contractions compared to young rats. Age‐related reductions in nitric oxide bioavailability due, in part, to elevated reactive O2 species (ROS) constrain muscle blood flow (Q̇ m). Therefore antioxidants may restore NO bioavailability, Q̇ m and ameliorate the reduction in PO2mv.PURPOSE:To test the hypothesis that antioxidants would elevate Q̇ m and therefore PO2mv.METHODS:PO2mv and Q̇ m were measured in the spinotrapezius of 20 anesthetized male F344xBN hybrid rats at rest and during 1 Hz contractions before and after antioxidant intravenous infusion (76mg/kg vitamin C and 52mg/kg tempol).RESULTS:Antioxidants did not change Q̇ m at rest but during contractions Q̇ m was reduced from 157 ± 28 to 91 ± 15 ml/min/100g (P<0.05). In the control condition, contractions invoked a biphasic PO2mv that fell from 30.6 ± 0.9 mmHg to a nadir of 16.8 ± 1.2 mmHg with an ‘undershoot’ of 2.8 ± 0.7 mmHg (P<0.05) below the subsequent steady‐state (19.7 ± 1.2 mmHg). Antioxidants elevated baseline PO2mv to 35.7 ± 0.8 mmHg (P<0.05) and reduced the ‘undershoot’ (P<0.05) without changing the steady‐state contracting PO2mv.CONCLUSION:At rest, antioxidants increased PO2mv without changing O2 delivery. During contractions antioxidants transformed the aged PO2mv profile to that of young rats.Supported by AHA Heartland Affiliate Grant #0750090Z.