INTRACELLULAR CA++ MOBILIZATION IN GRAY PLATELET SYNDROME. ELECTRONMICROSCOPIC STUDIES ON AEQUORIN LOADED PLATELETS

1987 ◽  
Author(s):  
K Mori ◽  
S Suzuki ◽  
K Sugai ◽  
Y Akutsu ◽  
M Ishikawa ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Peripheral Blood Smear ◽  
Buffer Solution ◽  
A 23187 ◽  
Tubular System ◽  
Intracellular Ca ◽  
Trace Line ◽  
Platelet Aggregates ◽  
Gray Platelet Syndrome ◽  
Second Peak

Light microscopic examinations on platelets in Gray Platelet Syndrome(GPS) showed peculiar gray colored platelets due to deficiency in ^-granules on the peripheral blood smear by May-Grunwald-Giemsa stain. Besides α-granule deficiency, however, several morphological abnormalities, especially abnormal features of dense tubular system(DTS) etc., were recognized in the transmission electronmicroscopic examinations. In the platelet function tests, release abnormalities rather than storage-pool deficiency were noted. We were strongly interested in the relationships between these morphological and functional abnormalities, because DTS in the platelets have been thought to be main storage sites of intracellular Ca ion.We examined the intracellular Ca++ mobilization using aequo-rin loaded platelets by means of Lumi-aggregometer(Salzman's method) under the stimulation of A-23187 and thrombin, and also morphological changes of platelets during the process of platelet aggregation by light |ipd transmission electronmicroscope.Intracellular Ca concentration increased dose-dependently after addition of A-23187 in both normal and GPS platelets. Namely, besides the first peak of emission which located at the same site as normal control, the slowly appearing second peak were recognized on the trace line by the addition of A-23187 and also abnormal by thrombin in GPS platelets. Transmission electronmi-crographs showed insufficient contraction of platelet-aggregates and malformation or wide appearance of pseudopods by the addition of A-23187 and thrombin. Most of the contractile gels, which were usually seen in the center of the platelets, were slightly enlarged and eccentric in the position. Delayed intracellular Ca mobilization were also noted even in the buffer solution containing EGTA.From above mentioned results, intracellular Ca++ mobilization were abnormal and these low and delayed mobilization were thou -ght to be related with prominent abnormal morphology, especially abnormalities of DTS in the GPS platelets.

Surface Morphological Changes Accompanying Dissolution of Bioactive Glass: Effect of Residual Stress

2008 ◽  
Vol 47-50 ◽  
pp. 1302-1306 ◽  
Author(s):  
John A. Nychka ◽  
Ding Li
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Bioactive Glass ◽  
Morphological Changes ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Mechanochemical Effect ◽  
Dissolution Behaviour ◽  
Glass Surfaces

We report our observations concerning the time evolution of surface morphology occurring during the in vitro immersion of bioactive glass surfaces in contact with phosphate buffer solution. We compare regions under intentionally produced residual stresses via micro-indentation to those where no indentation was performed. The sign of the residual stress is shown to be important for predicting dissolution behaviour; compression retards dissolution, whereas tension enhances dissolution. We analyze our results with a simple model for the work of bond dissociation. We report that a highly constrained residual compressive stress state, such as in an indent, leads to a work deficit in comparison to tension, which accounts for the slower dissolution rate of compressed bioactive glass. Such a mechanochemical effect suggests that the presence of residual stresses from the manufacture of biomedical implants and devices could lead to accelerated or delayed dissolution and that careful control of residual stresses should be sought for predictable performance in dissolvable materials.

PGE2 triggers recovery of transmucosal resistance via EP receptor cross talk in porcine ischemia-injured ileum

2001 ◽  
Vol 281 (2) ◽  
pp. G375-G381 ◽  
Author(s):  
Anthony T. Blikslager ◽  
Susan M. Pell ◽  
Karen M. Young
Keyword(s):  
Cross Talk ◽  
Splice Variants ◽  
Camp Content ◽  
Ep Receptors ◽  
Ussing Chambers ◽  
A 23187 ◽  
Receptor Interactions ◽  
Intracellular Ca ◽  
Ep Receptor ◽  
Receptor Cross Talk

16,16-Dimethyl-PGE2 (PGE2) may interact with one of four prostaglandin type E (EP) receptors, which signal via cAMP (via EP2 or EP4 receptors) or intracellular Ca2+ (via EP1 receptors). Furthermore, EP3 receptors have several splice variants, which may signal via cAMP or intracellular Ca2+. We sought to determine the PGE2 receptor interactions that mediate recovery of transmucosal resistance ( R) in ischemia-injured porcine ileum. Porcine ileum was subjected to 45 min of ischemia, after which the mucosa was mounted in Ussing chambers. Tissues were pretreated with indomethacin (5 μM). Treatment with the EP1, EP2, EP3, and EP4 agonist PGE2 (1 μM) elevated R twofold and significantly increased tissue cAMP content, whereas the EP2 and EP4 agonist deoxy-PGE1 (1 μM) or the EP1 and EP3 agonist sulprostone (1 μM) had no effect. However, a combination of deoxy-PGE1 and sulprostone stimulated synergistic elevations in R and tissue cAMP content. Furthermore, treatment of tissues with deoxy-PGE1 and the Ca2+ ionophore A-23187 stimulated synergistic increases in R and cAMP, indicating that PGE2 triggers recovery of R via EP receptor cross talk mechanisms involving cAMP and intracellular Ca2+.

Effect of Dextran 70 on the Platelet Distribution of Ex Vivo Thrombi

1979 ◽  
Author(s):  
M. åberg ◽  
A. Rausing ◽  
U. Hedner ◽  
S.-E. Bergent
Keyword(s):  
Light Microscopy ◽  
Factor Viii ◽  
Healthy Volunteers ◽  
Platelet Function ◽  
Small Dose ◽  
Ex Vivo ◽  
Morphological Changes ◽  
Dextran 70 ◽  
Platelet Aggregates

Infusion of dextran 70 impairs the function of factor VIII and increases the lysability of ex vivo thrombi. To find out whether this increased lysability is accompanied by any morphological changes of the thrombi dextran was infused into four healthy volunteers and one patient with von Wiilebrand’s disease. Dextran was also given to four dogs with 51Cr labelled platelets and 1-1abelled fibrinogen. The thrombi were studied in light microscopy and the distribution of isotopes measured. Dextran caused marked changes in the morphology of the thrombi. The platelet aggregates constituting the head were not formed and the platelets were more evenly distributed in the thrombi. The changes were most pronounced 2-4 hours after the infusion. In the patient with von Wiilebrand’s. disease the structure of the thrombus was abnormal already before the infusion of dextran. Even a small dose of dextran given to this patient prevented the formation of a platelet head. When factor VIII concentrate was given the platelet aggregates constituting the head of thrombus again formed. The findings indicate that factor VIII is of importance for the formation and coherence of the platelet aggregates in ex vivo thrombi. Dextran given intravenously reduces platelet aggregabiIity by impairing the function of factor VIII. The alteration of platelet function, accompanied bv profound changes in the morphology of ex vivo thrombi, may explain the increase in lysability which has been previously shown by us.

scholarly journals Increase in Platelet Volume and Aggregability in Adenosine Diphosphate Induced Pulmonary Micro Thromboembolism and Effect of Acetylsalicylic Acid Treatment

1977 ◽  
Author(s):  
T. Motomiya ◽  
H. Yamazaki
Keyword(s):  
Platelet Count ◽  
Acetylsalicylic Acid ◽  
Morphological Changes ◽  
Adenosine Diphosphate ◽  
Central Vein ◽  
Platelet Volume ◽  
Small Vessels ◽  
T Wave ◽  
Platelet Aggregates ◽  
Premature Beats

Several reports suggest that functional and morphological changes of platelet may occur in atherosclerotic and thromboembolic diseases and acetylsalicylic acid (ASA) has been considered as one of the possibly beneficial treatments of such conditions. Thirty male rabbits including 7 pretreated with ASA 200 mg/Kg p.o. for 4 days were catheterized. ECG, respiration, arterial and central venous pressures were recorded throughout the experiment. ADP 2 mg/Kg was injected into the central vein and citrated blood was obtained before, 30 seconds, 3, 10 and 45 minutes after the injection for platelet studies. Platelet count and volume were measured using with a Coulter Counter Zbl coupled with a Channelyzer C-1000. Platelet aggregability was determined by a Sienco aggregometer. Within several seconds after completion of ADP injection the animal developed bradycardia, premature beats, ischemic ST-T wave changes, hypotension, apnea and convulsion. Histology of the lung revealed small vessels being obstructed with platelet aggregates. In rabbits received ASA developed less bradycardia and hypotension and no ischemic ST-T wave changes, apnea or convulsion. Platelet count decreased at 30-second and increased at 10-minute after injection. Significant increases in platelet volume and aggregability were noted with no overt change in platelet morphology at 3 and 10 minutes after ADP injection. Correlation between platelet volume and aggregability was significant (r=0.60, P<0.05). This experiment demonstrated that platelet size or volume is not only dependent on its age but changes transiently under certain circumstances such as thrombosis. Treatment with ASA prevented cardiorespiratory disorders and changes in platelet volume and aggregability induced by administration of ADP.

Partial Agonists as Probes of Human Platelet Stimulus-Response Coupling in the Response to ADP and Adrenaline

1979 ◽  
Author(s):  
M.C. Scrutton ◽  
J.A. Grant ◽  
C.M. Egan
Keyword(s):  
Cyclic Amp ◽  
Human Platelet ◽  
Shape Change ◽  
Human Platelets ◽  
Stimulus Response ◽  
Partial Agonists ◽  
Aggregation Response ◽  
A 23187 ◽  
Intracellular Ca ◽  
Adp Receptor

Previous studies have identified 2', 3'-dialdehyde-ADF (oADP) and -dialcohol-ADP (or ABI as partial agonists at the ADP receptor, and Clonidine and methoxamine as partial agonists at the n-adrenoceptor.oADP and orADP cause shape change but not aggregation (Euxop, J, Biochem, 88, 543): Clonidine and methoxamine fail to cause aggregation but enhance the response to ADP and other agonists (Nature, in press). Preincubation of platelets with non-aggregating concentrations of the ionophore A-23187 induces a primai aggregation response to o ADP, and a primary aggregation + a secretion response to or ADH This response is specific to the partial agonists; is blocked by an ADP antagonist and by agents which raise cyclic AMP levels (e.g. PGE) or block intracellular Ca++ movemenl (e.g. tetracaine); and is not inhibited by specific chelation of extracellular Ca+. Under similar conditions A-23187 provokes a full aggregation response to Clonidine (which is blocked effectively by yohimbine but not by praiosin) and a primary aggrtion response to methoxamine. Preincubation of platelets with an adenylate cyclase inhibit; (SQ-22536) fails to provoke an aggregation response to oADP or orADP. These data suppt the concept that an increase in oytosolic [Ca2+], rather than a decrease in [cAMP], is key step in initiation of the response of human platelets to ADP and adrenaline.

Morphological Changes of Red Blood Cells in Peripheral Blood Smear of Patients with Pregnancy-related Hypertensive Disorders

2015 ◽  
Vol 46 (6) ◽  
pp. 479-483 ◽  
Author(s):  
Jorge Daniel Hernández Hernández ◽  
Onésimo Rangel Villaseñor ◽  
Javier Del Rio Alvarado ◽  
Roberto Ortega Lucach ◽  
Arturo Zárate ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Blood Smear ◽  
Morphological Changes ◽  
Peripheral Blood Smear ◽  
Hypertensive Disorders

scholarly journals Triggering Apoptotic Death of Human Malignant Melanoma A375.S2 Cells by Bufalin: Involvement of Caspase Cascade-Dependent and Independent Mitochondrial Signaling Pathways

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Yu-Ping Hsiao ◽  
Chun-Shu Yu ◽  
Chien-Chih Yu ◽  
Jai-Sing Yang ◽  
Jo-Hua Chiang ◽  
...  
Keyword(s):  
Malignant Melanoma ◽  
Morphological Changes ◽  
Chromatin Condensation ◽  
Signal Pathways ◽  
Dependent Manner ◽  
S2 Cells ◽  
Concentration Dependent Manner ◽  
Human Malignant Melanoma ◽  
Intracellular Ca ◽  
Venom Glands

Bufalin was obtained from the skin and parotid venom glands of toad and has been shown to induce cytotoxic effects in various types of cancer cell lines, but there is no report to show that whether bufalin affects human skin cancer cells. The aim of this investigation was to study the effects of bufalin on human malignant melanoma A375.S2 cells and to elucidate possible mechanisms involved in induction of apoptosis. A375.S2 cells were treated with different concentrations of bufalin for a specific time period and investigated for effects on apoptotic analyses. Our results indicated that cells after exposure to bufalin significantly decreased cell viability, and induced cell morphological changes and chromatin condensation in a concentration-dependent manner. Flow cytometric assays indicated that bufalin promoted ROS productions, loss of mitochondrial membrane potential (ΔΨm), intracellular Ca2+release, and nitric oxide (NO) formations in A375.S2 cells. Additionally, the apoptotic induction of bufalin on A375.S2 cells resulted from mitochondrial dysfunction-related responses (disruption of theΔΨmand releases of cytochromec, AIF, and Endo G), and activations of caspase-3, caspase-8 and caspase-9 expressions. Based on those observations, we suggest that bufalin-triggered apoptosis in A375.S2 cells is correlated with extrinsic- and mitochondria-mediated multiple signal pathways.

Abstract P245: Activation Of Protease-activated Receptors 1 Leads To Structural Changes In Immortalized Cultured Human Podocytes.

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Ruslan Bohovyk ◽  
Sherif Khedr ◽  
Christine A Klemens ◽  
Vladislav Levchenko ◽  
Olena Isaeva ◽  
...  
Keyword(s):  
Serine Proteases ◽  
Structural Changes ◽  
Calcium Influx ◽  
Morphological Changes ◽  
Confocal Imaging ◽  
Protease Activated Receptors ◽  
Ion Conductance ◽  
Downstream Signaling ◽  
Filtration Barrier ◽  
Intracellular Ca

Previous studies have suggested that activation of the protease-activated receptors (PAR) exacerbates the development of diabetic nephropathy. PARs are transmembrane proteins activated by extracellular serine proteases, such as thrombin and trypsin, which are frequently elevated in disease states. We hypothesize that serine protease activation of the PAR1 signaling cascade upregulates calcium channel activity and promotes excessive intracellular Ca 2+ ([Ca 2+ ] i ), leading to podocyte foot retraction, apoptosis, and glomerular filtration barrier (GFB) damage. Immunofluorescent labeling revealed the co-localization of PAR1 and podocyte marker nephrin in freshly isolated human glomeruli. To explore the functional role of PAR1 mediated signaling, we used an immortalized cultured human podocyte (hPod) cell line. Live confocal imaging revealed rapid elevation of [Ca 2+ ] i in response to a PAR1 specific agonist (TFLLR-NH 2 ). Moreover, preincubation with a PAR1 antagonist (RWJ 56100) completely blocked this effect (1616±48 vs. 206±135 a.u., for TFLLR vs. TFLLR+RJW, n<100 cells, p<0.05). Furthermore, we tested potential downstream signaling proteins in hPod cells after PAR1 activation using Western blot analysis. Application of TFLLR-NH 2 led to a decrease in PAR1 expression due to internalization and lysosomal degradation, accompanied by an increase in TRPC6 expression and time-dependent changes in p-ERK1/2 and PLC-γ1 cascades. We further used scanning ion-conductance microscopy (SICM) to detect morphological changes in podocytes, which measures real-time surface topography in hPod cells. This imaging revealed normal protrusion of lamellipodium under control conditions. In contrast, PAR1 activation led to retraction of the lamellipodium, and a significant decrease in surface area (+51±46 vs. -15±8 μm 2 , 30 min after application of vehicle or TFLLR, respectively; n=5, p<0.05). Our studies suggested that PAR1 is involved in GPCR-induced calcium influx in podocytes. Furthermore, these data demonstrate that PAR1-mediated signaling is involved in podocyte structural alterations and may increase [Ca 2+ ] i , potentially leading to loss of GFB integrity and podocyte apoptosis.

Abstract 2627: High Energy Defibrillation Impairs Myocyte Contractility and Intracellular Calcium Dynamics

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Giuseppe Ristagno ◽  
Tong Wang ◽  
Min-Shan Tsai ◽  
Shijie Sun ◽  
Wanchun Tang ◽  
...  
Keyword(s):  
Detection System ◽  
Myocardial Dysfunction ◽  
High Energy ◽  
Control Group ◽  
List Type ◽  
Sprague Dawley ◽  
Buffer Solution ◽  
Cardiomyocyte Contractility ◽  
Intracellular Ca ◽  
Myocyte Contractility

Introduction. High energy defibrillation is recognized to increase postresuscitation myocardial dysfunction. We examined the effects of defibrillation energies on contractility and intracellular Ca 2+ dynamics at the single cardiomyocyte level. Hypothesis. Increasing the defibrillation energy would produce correspondent reduction in myocyte contractility and impairment of intracellular Ca 2+ dynamics. Methods. Ventricular cardiomyocytes, obtained from adult Sprague-Dawley rat hearts, were loaded with Fura-2/AM. The myocytes were then placed in a chamber mounted on an inverted microscope and superfused with a buffer solution at 37 °C. The cells were field stimulated to contract at 0.5 Hz with a field stimulator (IonOptix Corporation, Milton, MA). Mechanical properties were assessed using a video-based edge-detection system (IonOptix Corporation, Milton, MA) and expressed as cell shortening percentage. Intracellular Ca 2+ dynamics were evaluated with a dual-excitation fluorescence photomultiplier system (IonOptix Myocam System) and inferred from the ratio of the fluorescence intensity at the two different wavelengths. Myocytes were randomized into 4 groups of 10 cells each, to receive: a single 0.5 Joule biphasic shock; a single 1 Joule biphasic shock; a single 2 Joule biphasic shock; and a control group without shock. The myocytes were paced for additional 4 min after the shock. Results. A 0.5 Joule shock did not have effects on cardiomyocyte contractility and intracellular Ca 2+ dynamics. Higher energy shock, i.e. 1 or 2 Joule, significantly impaired cardiomyocyte contractility and intracellular Ca 2+ dynamics (p < 0.01). These adverse effects were greater when higher energy was employed (p < 0.01). Table Conclusions. Higher defibrillation energy significantly impairs myocyte contractility. Reductions in cardiomyocyte shortening and intacellular Ca 2+ dynamics abnormalities were greater when higher energy shock was employed. Results

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