Half-maximal Response Research Articles

Effect of taurine on vascular dysfunction in an in vitro ischemia-reperfusion model of rat thoracic aorta.

The primary objective of this study was to evaluate the protective effect of taurine on endothelial dysfunction in a vascular ischemia-reperfusion (IR) model. Thoracic aortas of 9 male Sprague-Dawley rats (350-500g) were cut into rings and randomized into control (n = 7), IR (n = 8), IR + taurine 1mM (n = 7), IR + taurine 10mM (n = 8), IR + taurine 30mM (n = 8), and IR + taurine 100mM (n = 5) groups. Aortic rings in the IR group were stored in 0.9% saline at 4°C for 24h, placed in Krebs-Henseleit solution gassed with 95%O2 + 5%CO2 at 37°C, and exposed to sodium hypochlorite (200μM) for 30min. Responses to KCl (80mM), phenylephrine (10-10-10-4M), acetylcholine (10-10-10-4M), and sodium nitroprusside (SNP, 10-11-10-5M) were recorded. Emax (maximum response) and pD2 (negative logarithm of concentration producing half-maximum response) were calculated. IR decreased KCl contraction (control 1047 ± 176mg, IR 682 ± 128mg, p = 0.0007), which was reversed by 30 and 100mM taurine (960 ± 313mg, p = 0.02 and 1066 ± 488mg, p = 0.02, respectively). IR impaired phenylephrine, acetylcholine, and SNP responses (p < 0.0001). Taurine did not affect IR-impaired phenylephrine contractions. IR decreased both pD2 (control, 7.1 ± 0.1; IR, 6.0 ± 0.2; p < 0.01) and Emax (control, 83.5 ± 2.7%; IR, 26.8 ± 2.5%; p < 0.0001) of acetylcholine relaxation, both of which were reversed by 100mM taurine (pD2, 7.2 ± 0.1; p < 0.001; Emax, 45.4 ± 2.6%; p < 0.0001). For SNP relaxation, IR decreased pD2 (control 8.2 ± 0.1, IR 7.7 ± 0.1, p < 0.01), which was reversed by 100mM taurine (8.5 ± 0.1, p < 0.0001). Taurine protects endothelial function after IR injury. Further studies should explore the mechanism of this effect and the potential of adding taurine to vascular graft storage solutions.

Leucinostatins from fungal extracts block malaria transmission to mosquitoes

BackgroundMalaria is a mosquito-transmitted disease that kills more than half a million people annually. The lack of effective malaria vaccines and recently increasing malaria cases urge innovative approaches to prevent malaria. Previously, we reported that the extract from the soil-dwelling fungus Purpureocillium lilacinum, a common fungus from the soil, reduced Plasmodium falciparum oocysts in Anopheles gambiae midguts after mosquitoes contacted the treated surface before feeding.MethodsWe used liquid chromatography to fraction fungal crude extract and tract the active fraction using a contact-wise approach and standard membrane feeding assays. The purified small molecules were analyzed using precise mass spectrometry and tandem mass spectrometry.ResultsWe isolated four active small molecules from P. lilacinum and determined them as leucinostatin A, B, A2, and B2. Pre-exposure of mosquitoes via contact with very low-concentration leucinostatin A significantly reduced the number of oocysts. The half-maximal response or inhibition concentration (EC50) via pre-exposure was 0.7 mg/m2, similar to atovaquone but lower than other known antimalarials. The inhibitory effect of leucinostatin A against P. falciparum during intraerythrocytic development, gametogenesis, sporogonic development, and ookinete formation, with the exception of oocyst development, suggests that leucinostatins play a part during parasite invasion of new cells.ConclusionsLeucinostatins, secondary metabolites from P. lilacinum disrupt malaria development, particular transmission to mosquitoes by contact. The contact-wise malaria control as a nonconventional approach is highly needed in malaria-endemic areas.Graphical

Exercise-induced changes in myocardial glucose utilization during periods of active cardiac growth

Exercise training can promote physiological cardiac growth, which has been suggested to involve changes in glucose metabolism to facilitate hypertrophy of cardiomyocytes. In this study, we used a dietary, in vivo isotope labeling approach to examine how exercise training influences the metabolic fate of carbon derived from dietary glucose in the heart during acute, active, and established phases of exercise-induced cardiac growth. Male and female FVB/NJ mice were subjected to treadmill running for up to 4 weeks and cardiac growth was assessed by gravimetry. Cardiac metabolic responses to exercise were assessed via in vivo tracing of [13C6]-glucose via mass spectrometry and nuclear magnetic resonance. We found that the half-maximal cardiac growth response was achieved by approximately 1 week of daily exercise training, with near maximal growth observed in male mice with 2 weeks of training; however, female mice were recalcitrant to exercise-induced cardiac growth and required a higher daily intensity of exercise training to achieve significant, albeit modest, increases in cardiac mass. We also found that increases in the energy charge of adenylate and guanylate nucleotide pools precede exercise-induced changes in cardiac size and were associated with higher glucose tracer enrichment in the TCA pool and in amino acids (aspartate, glutamate) sourced by TCA intermediates. Our data also indicate that the activity of collateral biosynthetic pathways of glucose metabolism may not be markedly altered by exercise. Overall, this study provides evidence that metabolic remodeling in the form of heightened energy charge and increased TCA cycle activity and cataplerosis precedes cardiac growth caused by exercise training in male mice.

Lysine-Cysteine-Serine-Tryptophan inserted into the DNA-binding domain of human mineralocorticoid receptor increases transcriptional activation by aldosterone

Due to alternative splicing in an ancestral DNA-binding domain (DBD) of the mineralocorticoid receptor (MR), humans contain two almost identical MR transcripts with either 984 amino acids (MR-984) or 988 amino acids (MR-988), in which their DBDs differ by only four amino acids, Lys,Cys,Ser,Trp (KCSW). Human MRs also contain mutations at two sites, codons 180 and 241, in the amino terminal domain (NTD). Together, there are five distinct full-length human MR genes in GenBank. Human MR-984, which was cloned in 1987, has been extensively studied. Human MR-988, cloned in 1995, contains KCSW in its DBD. Neither this human MR-988 nor the other human MR-988 genes have been studied for their response to aldosterone and other corticosteroids. Here, we report that transcriptional activation of human MR-988 by aldosterone is increased by about 50 % compared to activation of human MR-984 in HEK293 cells transfected with the TAT3 promoter, while the half-maximal response (EC50) is similar for aldosterone activation of MR-984 and MR-988. Transcriptional activation of human MR also depends on the amino acids at codons 180 and 241. Interestingly, in HEK293 cells transfected with the MMTV promoter, transcriptional activation by aldosterone of human MR-988 is similar to activation of human MR-984, indicating that the promoter has a role in the regulation of the response of human MR-988 to aldosterone. The physiological responses to aldosterone and other corticosteroids in humans with MR genes containing KCSW and with differences at codons 180 and 241 in the NTD warrant investigation.

A small-molecule hemostatic agent for the reversal of direct oral anticoagulant–induced bleeding

BackgroundThe bleeding risk associated with direct oral anticoagulants (DOACs) remains a major concern, and rapid reversal of anticoagulant activity may be required. Although specific and nonspecific hemostatic biotherapies are available, there is a need for small-molecule DOAC reversal agents that are simple and cost-effective to produce, store, and administer. ObjectivesTo identify and characterize a small molecule with procoagulant activity as a DOAC reversal agent. MethodsWe sought to identify a small procoagulant molecule by screening a chemical library with a plasma clotting assay. The selected molecule was assessed for its procoagulant properties and its ability to reverse the effects of the DOACs in a thrombin generation assay. Its activity as a DOAC reversal agent was also evaluated in a tail-clip bleeding assay in mice. ResultsThe hemostatic molecule (HeMo) dose-dependently promoted thrombin generation in plasma, with dose values effective in producing half-maximum response ranging between 3 and 5 μM, depending on the thrombin generation assay parameter considered. HeMo also restored impaired thrombin generation in DOAC-spiked plasma and reversed DOAC activity in the mouse bleeding model. HeMo significantly reduced apixaban-induced bleeding from 709 to 65 μL (vs 43 μL in controls; P < .01) and dabigatran-induced bleeding from 989 to 155 μL (vs 126 μL in controls; P < .01). ConclusionHeMo is a small-molecule procoagulant that can counterbalance hemostatic disruption by a thrombin inhibitor (dabigatran) or factor Xa inhibitors (apixaban and rivaroxaban). The compound’s effective clot formation and versatility make it a possible option for managing the inherent hemorrhagic risk during DOAC therapy.

Molecular determinants of ligand efficacy and potency in GPCR signaling.

Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) bind to extracellular ligands and drugs and modulate intracellular responses through conformational changes. Despite their importance as drug targets, the molecular origins of pharmacological properties such as efficacy (maximum signaling response) and potency (the ligand concentration at half-maximal response) remain poorly understood for any ligand-receptor-signaling system. We used the prototypical adrenaline-β2 adrenergic receptor-G protein system to reveal how specific receptor residues decode and translate the information encoded in a ligand to mediate a signaling response. We present a data science framework to integrate pharmacological and structural data to uncover structural changes and allosteric networks relevant for ligand pharmacology. These methods can be tailored to study any ligand-receptor-signaling system, and the principles open possibilities for designing orthosteric and allosteric compounds with defined signaling properties.

Effects of Remimazolam on Intracellular Calcium Dynamics in Myotubes Derived from Patients with Malignant Hyperthermia and Functional Analysis of Type 1 Ryanodine Receptor Gene Variants.

Remimazolam is a novel general anesthetic and its safety in patients with malignant hyperthermia (MH) is unknown. We used myotubes derived from the skeletal muscle of patients with MH to examine the response to ryanodine receptor 1 (RYR1) agonist and remimazolam in MH-susceptible patients. Patients underwent muscle biopsy for the Ca2+-induced Ca2+ release (CICR) rate test, a diagnostic tool for MH in Japan. Ten patients had myotubes obtained from skeletal muscle cultures, and the genes associated with malignant hyperthermia in these patients were analyzed. The EC50 of caffeine, cresol, and remimazolam to induce intracellular calcium concentration change were compared between myotubes from CICR-negative genetic test patients and myotubes from other patients. Eight of the ten were CICR-positive, five of whom had RYR1 causative gene mutations or variants. Two patients had CICR-negative genetic tests, and as expected had the highest EC50 (the concentration of a drug that gives a half-maximal response) in response to caffeine, 4CmC and remimazolam. Three patients had a positive CICR but no known variants in RYR1 or CACNA1S (voltage-gated calcium channel subunit alpha1S). Myotubes in these patients had significantly lower EC50s for all agents than myotubes in CICR-negative patients. When myotubes from a patient who was CICR-negative and had no gene variant were used as a control, myotubes from CICR-positive patients were more hyper-responsive than controls to all stimulants used. The EC50 for remimazolam was lowest for myotubes from CICR-positive, RYR1-mutant patients, at 206 µM (corresponding to 123 µg/mL). The concentration was more than 80-times higher than the clinical concentration. RYR1 gene variants in R4645Q and W5020G were shown to be causative gene mutations for MH. Intracellular calcium in myotubes from MH patients are elevated at high concentrations of remimazolam but not at clinically used concentrations of remimazolam. Remimazolam appears to be safe to use in patients with MH.

LIGHT ADAPTATION OF RETINAL ROD BIPOLAR CELLS.

The sensitivity of retinal cells is altered in background light to optimize the detection of contrast. For scotopic (rod) vision, substantial adaptation occurs in the first two cells, the rods and rod bipolar cells (RBCs), through sensitivity adjustments in rods and postsynaptic modulation of the transduction cascade in RBCs. To study the mechanisms mediating these components of adaptation, we made whole-cell, voltage-clamp recordings from retinal slices of mice from both sexes. Adaptation was assessed by fitting the Hill equation to response-intensity relationships with the parameters of half-maximal response (I1/2 ), Hill coefficient (n), and maximum response amplitude (Rmax ). We show that rod sensitivity decreases in backgrounds according to the Weber-Fechner relation with an I1/2 of about 50 R* s-1 The sensitivity of RBCs follows a near-identical function, indicating that changes in RBC sensitivity in backgrounds bright enough to adapt the rods are mostly derived from the rods themselves. Backgrounds too dim to adapt the rods can however alter n, relieving a synaptic nonlinearity likely through entry of Ca2+ into the RBCs. There is also a surprising decrease of Rmax , indicating that a step in RBC synaptic transduction is desensitized or that the transduction channels became reluctant to open. This effect is greatly reduced after dialysis of BAPTA at a membrane potential of +50 mV to impede Ca2+ entry. Thus the effects of background illumination in RBCs are in part the result of processes intrinsic to the photoreceptors and in part derive from additional Ca2+-dependent processes at the first synapse of vision.SIGNIFICANCE STATEMENT:Light adaptation adjusts the sensitivity of vision as ambient illumination changes. Adaptation for scotopic (rod) vision is known to occur partly in the rods and partly in the rest of the retina from presynaptic and postsynaptic mechanisms. We recorded light responses of rods and rod bipolar cells to identify different components of adaptation and study their mechanisms. We show that bipolar-cell sensitivity largely follows adaptation of the rods, but that light too dim to adapt the rods produces a linearization of the bipolar-cell response and a surprising decrease in maximum response amplitude, both mediated by a change in intracellular Ca2+ These findings provide a new understanding of how the retina responds to changing illumination.

Treating Lower Urinary Tract Symptoms in Older Adults: Intravesical Options.

This article provides an overview of the diagnosis and the treatment of lower urinary tract symptoms in older adults complicated by the neurodegenerative changes in the micturition reflex and further confounded by age-related decline in hepatic and renal clearance raising the propensity of adverse drug reactions. The first-line drug treatment for lower urinary tract symptoms, orally administered antimuscarinics, fails to reach the equilibrium dissociation constant of muscarinic receptors even at their maximum plasma concentration and tends to evoke a half-maximal response at a muscarinic receptor occupancy of just 0.206% in the bladder with a minimal difference from exocrine glands, which raises the adverse drug reaction risk. On the contrary, intravesical antimuscarinics are instilled at concentrations 1000-fold higher than the oral maximum plasma concentration and the equilibrium dissociation constant erects a downhill concentration gradient that drives passive diffusion and achieves a mucosal concentration around ten-fold lower than the instilled concentration for a long-lasting occupation of muscarinic receptors in mucosa and sensory nerves. A high local concentration of antimuscarinics in the bladder triggers alternative mechanisms of action and is supposed to engage retrograde transport to nerve cell bodies for neuroplastic changes that underlie a long-lasting therapeutic effect, while an intrinsically lower systemic uptake of the intravesical route lowers the muscarinic receptor occupancy of exocrine glands to lower the adverse drug reaction relative to the oral route. Thus, the traditional pharmacokinetics and pharmacodynamics of oral treatment are upended by intravesical antimuscarinics to generate a dramatic improvement (~ 76%) noted in a meta-analysis of studies enrolling children with neurogenic lower urinary tract symptoms on the primary endpoint of maximum cystometric bladder capacity as well as the secondary endpoints of filling compliance and uninhibited detrusor contractions. The therapeutic success of intravesical multidose oxybutynin solution or oxybutynin entrapped in the polymer for sustained release in the pediatric populationbodes well for patients with lower urinary tract symptoms at the other extreme of the age spectrum. Though generally used to predict oral drug absorption, Lipinski's rule of five can also explain the ten-fold lower systemic uptake from the bladder of positively charged trospium over oxybutynin, a tertiary amine. Chemodenervation by an intradetrusor injection of onabotulinumtoxinA is merited for patients with idiopathic overactive bladder discontinuing oral treatment because of a lack of efficacy. However, age-related peripheral neurodegeneration potentiates the adverse drug reaction risk of urinary retention that motivates the quest of liquid instillation, delivering larger fraction of onabotulinumtoxinA to the mucosa as opposed to muscle by an intradetrusor injection can also probe the neurogenic and myogenic predominance of idiopathic overactive bladder. Overall, the treatment paradigm of lower urinary tract symptoms in older adults should be tailored to individual's overall health status and the risk tolerance for adverse drug reactions.

Reconsidering the role of receptors for SARS‐CoV‐2 in clear cell renal cell carcinoma: Friends or foes

Reconsidering the role of receptors for SARS‐CoV‐2 in clear cell renal cell carcinoma: Friends or foes

Calcium-dependent subquantal peptide release from single docked lawn-resident vesicles of pituitary lactotrophs

Regulated exocytosis consists of the fusion between vesicles and the plasma membranes, leading to the formation of a narrow fusion pore through which secretions exit the vesicle lumen into the extracellular space. An increase in the cytosolic concentration of free Ca2+ ([Ca2+]i) is considered the stimulus of this process. However, whether this mechanism can be preserved in a simplified system of membrane lawns with docked secretory vesicles, devoid of cellular components, is poorly understood. Here, we studied peptide discharge from individual secretory vesicles docked at the plasma membrane, prepared from primary endocrine pituitary cells (the lactotrophs), releasing hormone prolactin. To label secretory vesicles, we transfected lactotrophs to express the fluorescent atrial natriuretic peptide (ANP.emd), previously shown to be expressed in and released from prolactin-containing vesicles. We used stimulating solutions containing different [Ca2+] to evoke vesicle peptide discharge, which appeared similar in membrane lawns and in intact stimulated lactotrophs. All vesicles examined discharged peptides in a subquantal manner, either exhibiting a unitary or sequential time course. In the membrane lawns, the unitary vesicle peptide discharge was predominant and slightly slower than that recorded in intact cells, but with a shorter delay with respect to the stimulation onset. This study revealed directly that Ca2+ triggers peptide discharge from docked single vesicles in the membrane lawns with a half-maximal response of ∼8 µM [Ca2+], consistent with previous whole-cell patch-clamp studies in endocrine cells where the rapid component of exocytosis, interpreted to represent docked vesicles, was fully activated at <10 µM [Ca2+]. Interestingly, the sequential subquantal peptide vesicle discharge indicates that fluctuations between constricted and dilated fusion pore states are preserved in membrane lawns and that fusion pore regulation appears to be an autonomously controlled process.

On nonlinearity in field-effect transistor-based binding assay response

Field-effect transistor (FET)-based biosensors have demonstrated highly sensitive label-free detection of a plethora of biomolecules as next-generation binding assays. While the dose–response curve of affinity-based binding assays generally has a nonlinear shape, any distortion contributed by the FET transducers has not been well understood. In this paper, we show that the signal transduction of FET sensors plays an important role in shaping their dose–response curves when operating in the nonlinear screening regime. We have found that the nonlinearity arising from the counterion screening in the electrical double layer could distort the relationship between the device flatband voltage shift and the analyte concentrations in (1) lowering its half-maximal response concentration as well as the sensitive detection range and (2) expanding its dynamic range. Negligence of such nonlinearity would introduce errors in the extracted affinity properties of the analyte–receptor pair. This work provides useful guidelines for designing FET-based binding assays and interpreting their measurement data.

Aldosterone and dexamethasone activate African lungfish mineralocorticoid receptor: Increased activation after removal of the amino-terminal domain

Aldosterone, the main physiological mineralocorticoid in humans and other terrestrial vertebrates, first appears in lungfish, which are lobe-finned fish that are forerunners of terrestrial vertebrates. Aldosterone activation of the MR regulates internal homeostasis of water, sodium and potassium, which was critical in the conquest of land by vertebrates. We studied transcriptional activation of the slender African lungfish MR by aldosterone, other corticosteroids and progesterone and find that aldosterone, 11-deoxycorticosterone, 11-deoxycortisol and progesterone have half-maximal responses (EC50 s) below 1 nM and are potential physiological mineralocorticoids. In contrast, EC50 s for corticosterone and cortisol were 23 nM and 66 nM, respectively. Unexpectedly, truncated lungfish MR, consisting of the DNA-binding, hinge and steroid-binding domains, had a stronger response to corticosteroids and progesterone than full-length lungfish MR, indicating that the N-terminal domain represses steroid activation of lungfish MR, unlike human MR in which the N-terminal domain contains an activation function. BLAST searches of GenBank did not retrieve a GR ortholog, leading us to test dexamethasone and triamcinolone for activation of lungfish MR. At 10 nM, both synthetic glucocorticoids are about 4-fold stronger than 10 nM aldosterone in activating full-length lungfish MR, leading us to propose that lungfish MR also functions as a GR.

In vitro anti-proliferative effect of capecitabine (Xeloda) combined with mocetinostat (MGCD0103) in 4T1 breast cancer cell line by immunoblotting.

Objective(s):Mouse breast cancer cell line 4T1 can accurately mimic the response to immune receptors and targeting therapeutic agents. Combined therapy has emerged as an important strategy with reduced side effects and maximum therapeutic effect. Mocetinostat (MGCD0103) is one of the members of Class I Histone Deacetylase Inhibitors (HDACi) and its mechanism of action has not been defined, yet. Capecitabine (Xeloda) is an antimetabolite and currently is widely utilized to treat a wide range of solid tumors. The aim of this study was to investigate the effects of the capecitabine, mocetinostat and their combined application on the 4T1 cell line. Materials and Methods:The effects of combined administration of mocetinostat and capecitabine on 4T1 cells were investigated by cell viability and migration assays, apoptosis analysis, and Western blotting technique.Results:The concentrations of drugs that give a half-maximal response (IC50) were detected for capecitabine (1700 µM), mocetinostat (3,125 µM), and 50 µM Capecitabine+1,5 µM Mocetinostat for 48 hr. In capecitabine+mocetinostat combine group, we observed that cell migration decreased, DNA fragmentation increased compared to the control group. capecitabine + mocetinostat group induced apoptosis by decreasing Bcl-2, PI3K, Akt, c-myc protein levels, while increasing Bax, Caspase-3, PTEN, cleaved-PARP, Caspase-7, Caspase-9, p53, cleaved-Cas-9 protein levels in 4T1 cells. Conclusion:Capecitabine and mocetinostat played a toxic role through inducing apoptosis on 4T1 cancer cells in a time- and concentration-dependent manner. These results showed that combined therapy with low concentrations were detected to be more effective than that with high-concentration alone drug treatment.

Effect of molecular mass and sulfate content of fucoidan from Sargassum siliquosum on antioxidant, anti-lipogenesis, and anti-inflammatory activity

Macroalgae (seaweeds) are abundant in functional polysaccharides known for their unique biochemical activities. In this study, the antioxidant, anti-lipogenic, and anti-inflammatory activities of the fucoidan extracted from brown seaweed Sargassum siliquosum were investigated by 1,1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging ability, lipid synthesis inhibition, and suppression of pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) production, respectively. To examine the effect of molecular mass on fucoidan's bioactivities above, the extracted fucoidan was subject to hydrogen peroxide-mediated partial hydrolysis to obtain lower molecular mass compounds within the range of 107.3-3.2kDa. Results indicated that fucoidan's antioxidant activity increased with a corresponding decrease in molecular mass; the dosage for the half-maximal response (EC50) dropped from 2.58 to 1.82mg/mL when the molecular mass decreased from 107.3 to 3.2kDa. In addition, both the anti-lipogenesis and anti-inflammatory activities of fucoidan were significantly enhanced by 71.1% and 36.7%, respectively, when the molecular mass decreased to about 3kDa. To further test the effect of sulfation on fucoidan's bioactivities, low molecular mass fucoidan was treated with SO3-DMF to increase the sulfate content. The results indicated that when sulfate content increased from 18.7% to 32.1%, EC50 of DPPH decreased from 1.82mg/mL to 0.86mg/mL and the anti-inflammatory activity also increased by 35.2%; however, the anti-lipogenesis activity decreased.

Suppression of top-down influence decreases neuronal excitability and contrast sensitivity in the V1 cortex of cat

How top-down influence affects neuronal activity and information encoding in the primary visual cortex (V1) remains elusive. This study examined changes of neuronal excitability and contrast sensitivity in cat V1 cortex after top-down influence of area 7 (A7) was modulated by transcranial direct current stimulation (tDCS). The neuronal excitability in V1 cortex was evaluated by visually evoked field potentials (VEPs), and contrast sensitivity (CS) was assessed by the inverse of threshold contrast of neurons in response to visual stimuli at different performance accuracy. We found that the amplitude of VEPs in V1 cortex lowered after top-down influence suppression with cathode-tDCS in A7, whereas VEPs in V1 did not change after sham-tDCS in A7 and nonvisual cortical area 5 (A5) or cathode-tDCS in A5 and lesioned A7. Moreover, the mean CS of V1 neurons decreased after cathode-tDCS but not sham-tDCS in A7, which could recover after tDCS effect vanished. Comparisons of neuronal contrast-response functions showed that cathode-tDCS increased the stimulus contrast required to generate the half-maximum response, with a weakly-correlated reduction in maximum response but not baseline response. Therefore, top-down influence of A7 enhanced neuronal excitability in V1 cortex and improved neuronal contrast sensitivity by both contrast gain and response gain.

Anthocyanins Activate Membrane Estrogen Receptors With Nanomolar Potencies to Elicit a Nongenomic Vascular Response Via NO Production.

BackgroundThe vascular pharmacodynamics of anthocyanins is only partially understood. To examine whether the anthocyanin‐induced vasorelaxation is related to membrane estrogen receptor activity, the role of ERα or GPER antagonism was ascertained on anthocyanins or 17‐β estradiol‐(E2) induced vasodilatations and NO production.Methods and ResultsThe rat arterial mesenteric bed was perfused with either anthocyanins or corresponding 3‐O‐glycosides, or E2, to examine rapid concentration‐dependent vasorelaxations. The luminally accessible fraction of NO in mesenteric perfusates before and after anthocyanins or E2 administration was quantified. Likewise, NO‐DAF signal detected NO production in primary endothelial cells cultures incubated with anthocyanins or E2 in the absence and presence of ERα (ICI 182,780) or GPER (G‐36) selective antagonists. Anthocyanins or corresponding glycosides elicited, within minutes, vasodilation with nanomolar potencies; half maximal anthocyanin response reached 50% to 60% efficacy, in contrast to acetylcholine. The vasorelaxation is of rapid onset and exclusively endothelium‐dependent; NOS inhibition annulled the vasorelaxation. The delphinidin vascular response was not modified by 100 nmol/L atropine but significantly attenuated by joint application of ICI plus G‐36 (52±4.6 versus 8.5±1.5%), revealing the role of membrane estrogen receptors. Moreover, the anthocyanin or E2‐induced NO production was antagonized up to 70% by these antagonists. NO‐DAF signal elicited by anthocyanins was annulled by NOS inhibition or by ICI plus G‐36 addition.ConclusionsThe biomedical effect of anthocyanins or 3‐O‐glycosylates derivatives contained in naturally purple‐colored foods or berries is due to increased NO production, and not to the phytochemical's antioxidant potential, highlighting the nutraceutical role of natural products in cardiovascular diseases.

A potential objective marker in first-episode schizophrenia based on abnormal niacin response

The lack of objective diagnostic markers has long been a challenge in the clinical management of schizophrenia (SZ). The current bivariate cut-offs method is an objective quantification of niacin skin flush abnormality (NFA) for identifying the SZ subgroup. However, the sensitivity of approximately 30% limits the application of NFA as a marker for detecting SZ. A laser Doppler flowmeter was employed to test the niacin skin-flushing response in 123 patients with first-episode psychosis including first-episode SZ (FES, n = 82) and psychotic bipolar disorders (PBP, n = 41), and non-psychiatric comparisons (NPC, n = 80). We modified the bivariate cut-offs using a combination of the niacin concentration corresponding to the half-maximal blood flow response (EC50) and a new quantitative indicator called the overall trend area (OTA). The NFA used this study method predicted FES in the NPC group with 57% sensitivity, 89% specificity, and 73% accuracy compared to the 28% sensitivity, 91% specificity, and 59% accuracy of the existing method. This novel method could discern FES from the PBP group with an accuracy of 62%, compared with the 45% of the old method. In addition, we also discuss whether the bivariate cut-offs were occasional by adjusting the cut-offs threshold. The experimental results showed that the sensitivity and specificity were most stable when using the study method. The study indicates that NFA using modified bivariate cut-offs may be a potential objective marker in FES, and the niacin skin test could be feasible for early diagnosis and treatment of SZ.

Novelty of synergistic and cytotoxicity activities of silver nanoparticles produced by Lactobacillus acidophilus

Silver nanoparticles (AgNPs) have been recognized for their unique physical and chemical properties, silver nanoparticles (AgNPs) have identified themselves as one of the most shows potential nanoparticles in biomedical and biological applications, including anticancer, drug delivery, and antimicrobial agents. The release of [Ag +], which is toxic to microorganisms, could be responsible for AgNPs’ bactericidal properties. Synthesis of silver nanoparticles (NPs) using lactic acid bacteria could be a good environmentally friendly substitute for physical and chemical methods. Lactobacillus acidophilus was identified by biochemical and molecular methods and rummage sale for the green mixture of AgNPs. The AgNPs produced within the L. acidophilus culture medium were characterized by color change after L. acidophilus development by 1 mM AgNO3 at 37 °C. The NPs configuration was established by UV–visible at 434 nm. Characterization by transmission electron microscopy (TEM) proved that the sphere-shaped poly-dispersed AgNPs were in the scope variety of 19–25 nm. Fourier-transform infrared spectroscopy showed high levels of AgNP-steadying proteins and other subordinate metabolites. X-ray deflection exposed a face-centered cubic deflection spectrum by a crystal-like countryside. The antimicrobial action of AgNPs was verified against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Salmonella enterica), Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), and a fungus (Candida albicans). The objective of this study was to investigate the biosynthesis of silver NPs using Lactobacillus and it is antibacterial and cytotoxicity activities of synthesized nanoparticles. The E. coli and S. enterica were highly susceptible, which were (21 and 20 mm), whereas S. aureus and C. albicans were the least susceptible, which were (10 and 9 mm). The findings on the cytotoxicity of AgNPs against Caco, A549, and HepG2 cell lines of cancer showed that the concentrations giving half-maximal responses were 5, 15, and 30 mg/ml, respectively. This study presents a well-organized and rapid method of synthesizing stable AgNPs using L. acidophilus with high antimicrobial and anticancer activities.

Characterization of Potency of the P2Y13 Receptor Agonists: A Meta-Analysis.

P2Y13 is an ADP-stimulated G-protein coupled receptor implicated in many physiological processes, including neurotransmission, metabolism, pain, and bone homeostasis. Quantitative understanding of P2Y13 activation dynamics is important for translational studies. We systematically identified PubMed annotated studies that characterized concentration-dependence of P2Y13 responses to natural and synthetic agonists. Since the comparison of the efficacy (maximum response) is difficult for studies performed in different systems, we normalized the data and conducted a meta-analysis of EC50 (concentration at half-maximum response) and Hill coefficient (slope) of P2Y13-mediated responses to different agonists. For signaling events induced by heterologously expressed P2Y13, EC50 of ADP-like agonists was 17.2 nM (95% CI: 7.7–38.5), with Hills coefficient of 4.4 (95% CI: 3.3–5.4), while ATP-like agonists had EC50 of 0.45 μM (95% CI: 0.06–3.15). For functional responses of endogenously expressed P2Y13, EC50 of ADP-like agonists was 1.76 μM (95% CI: 0.3–10.06). The EC50 of ADP-like agonists was lower for the brain P2Y13 than the blood P2Y13. ADP-like agonists were also more potent for human P2Y13 compared to rodent P2Y13. Thus, P2Y13 appears to be the most ADP-sensitive receptor characterized to date. The detailed understanding of tissue- and species-related differences in the P2Y13 response to ADP will improve the selectivity and specificity of future pharmacological compounds.