REORGANIZATION OF ACTIN AND MYOSIN IN THE ACTIVATED PLATELETS

1987 ◽  
Author(s):  
N Shibatay ◽  
K Tanaka ◽  
K Okamoto ◽  
T Onji
Keyword(s):  
Platelet Rich Plasma ◽  
Shape Change ◽  
Protein A ◽  
Gel Filtration ◽  
Activation Process ◽  
Clot Retraction ◽  
Arrow Head ◽  
Cover Slip ◽  
Glass Cover ◽  
Glass Cover Slip

This study was done to clarify the intracellular dynamic arrangements of myosin(My) and actin(Ac) in activation process of human platelets (PLs) from unactivated to activated stage (clot retraction) in electron microscopy. The observation of unactivated PLs was done either in the fresh whole blood fixed directly with 0.1 % glutaraldehyde or in PLs isolated by gel filtration of platelet rich plasma(PRP) containing prostaglandin I2 (10 ng/ml). The isolated PLs mounted on a glass cover slip were used as activated PLs (adrerent ones). The contracted PLs were prepared in PRP incubated with thrombin (0.5 u/ml) and 20 mM CaCl- for 10-60 min. Treating PLs with 0.15 % Triton X-100 containing 0.05 % glutaraldehyde produced cytoskeleton. My and F-Ac were identified by an indirect immuno-cytochemical method using the specific antibody (rabbit IgG) against PL-My and protein A-gold and by demonstration of in “arrow-head” decoration by Ishikawa's method using skeletal meromyosin (HMM), respectively. [Results] (1) Unactivated PLs. Mys in monomer or oligomer distributed homogenously in scare association with cytoskeleton. Cytoskeletons were exclusively composed of F-Ac networks of crossolinked short filaments which were thinly distributed in the cytoplasm with partial connection to the cell membrance. (2) Surface activated spreading PLs. PLs adhered to the glass cover slip in dendritic forms. Mys were densely located around granulomere and formed linear arrays associated with F-Ac filaments of the cytoskeleton surrounding the granulomere and running straightly in cytoplasm. (3) Contracted PLs. Activated PLs protruded several filopodia in which networks or bundles of F-Ac filaments were found connecting to extracellular fibrin strand through cell membrene. Microfilaments formed arrow-head decoration with HMM pointing toward the cell body. The cytoskeleton in contracted PLs contained thick filaments of My-polymers attaching to F-Ac filaments end by end. It is concluded that the reorganization of Ac-My is the basis for the shape change, secretion and clot retraction of activated PLs.

scholarly journals Pyrosequencing on a glass surface

Lab on a Chip ◽  
2016 ◽  
Vol 16 (6) ◽  
pp. 1063-1071 ◽  
Author(s):  
Ana V. Almeida ◽  
Andreas Manz ◽  
Pavel Neužil
Keyword(s):  
Glass Surface ◽  
Open Surface ◽  
Cover Slip ◽  
Glass Cover ◽  
Glass Cover Slip ◽  
Dna Pyrosequencing ◽  
Coated Surface

We demonstrated DNA pyrosequencing at the plain hydrophobically coated surface of a microscope glass cover slip using open-surface microfluidics.

Bilinexin, a Snake C-type Lectin from Agkistrodon bilineatus Venom Agglutinates Platelets via GPIb and α2β1

2001 ◽  
Vol 86 (11) ◽  
pp. 1277-1283 ◽  
Author(s):  
Xiao-Yan Du ◽  
Alexey Navdaev ◽  
Jeannine Clemetson ◽  
Edith Magnenat ◽  
Timothy Wells ◽  
...  
Keyword(s):  
Platelet Rich Plasma ◽  
Shape Change ◽  
Polyclonal Antibodies ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Binding Studies ◽  
Good Tool ◽  
Reducing Conditions ◽  
Sds Page ◽  
Lectin Family

SummaryA new snake protein, named bilinexin, has been purified from Agkistrodon bilineatus venom by ion-exchange chromatography and gel filtration chromatography. Under non-reducing conditions it has a mass of 110 kDa protein on SDS-PAGE. On reduction, it can be separated into five subunits with masses in the range 13-25 kDa. The N-terminal sequences of these subunits are very similar to those of convulxin or the alboaggregins, identifying bilinexin as a new member of the snake C-type lectin family, unusual in having multiple subunits. Bilinexin agglutinates fixed platelets, washed platelets and platelet rich plasma (PRP) without obvious activation (shape change) as confirmed by light microscope examination. Both inhibitory and binding studies indicate that antibodies against α2β1 inhibit not only platelet agglutination induced by bilinexin, but also bilinexin binding to platelets. VM16d, a monoclonal anti-GPIbα antibody, completely inhibits platelet agglutination induced by bilinexin, and polyclonal antibodies against GPIbα prevent its binding to platelets. However, neither convulxin, polyclonal anti-GPVI antibodies, nor GPIIb/IIIa inhibitors affect its binding to and agglutination of platelets. Bilinexin neither activates GPIIb/IIIa integrin on platelets nor induces tyrosine phosphorylation of platelet proteins, nor increases intracellular Ca2+ in platelets. Like alboaggregin B, bilinexin agglutinates platelets, which makes it a good tool to investigate the differences in mechanism between snake C-type lectins causing platelet agglutination and those that induce full activation.

Montreal Platelet Syndrome (MPS):Ultrastructural, Biochemical And Functional Studies

1981 ◽  
Author(s):  
M M Frojmovie ◽  
J G Milton ◽  
S S Tang
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Protein Profile ◽  
Peripheral Blood Smear ◽  
Ionophore A23187 ◽  
Clot Retraction ◽  
Platelet Counts

MPS is characterized by autosomal dominant inheritance thrombocytopenia (5,000-120,000 μl-1), abnormally large platelets on peripheral blood smear, spontaneous aggregation (SA), normal clot retraction and thromboplastin formation, nypervolumetric shape change and normal amounts of plasma membrane. Here we describe further characteristics of MPS for 3 siblings /5 affected family members. The ultrastructural features of MPS platelets were normal except for the high frequency of giant granules. Platelet aggregation (PA) was studied in citrated platelet-rich plasma at platelet counts of 5,000-40,000 μl-1 and was quantitated microscopically from the decrease in single platelet count. PA could be increased over that due to SA alone by the addition of ADP, adrenalin, collagen, ionophore A23187, arachidonic acid and ristocetin, suggesting that the response to these agents may be normal. The ristocetin-induced increase in PA was completely blocked by an IgG specific for BSS. In contrast, over a 4 year period, thrombin (0.2 units/ml) either did not or only slightly increased PA over SA for 3/3 donors. However, MPS platelets pelleted from ACD-PRP and resuspended in Tyrodes’, pH 7.4 at a platelet count of ~ 200,000 μ1-1 showed a normal response to thrombin by aggregometry. Only one donor’s platelets had both reduced sialic acid and glycoprotein (G.P.) 1 reduction/abnormality with otherwise normal G.P. and protein profile, while the other 2 siblings’ platelets showed no such abnormalities. The above results indicate that biochemical variability exists for MPS platelets from different affected siblings. Moreover, our observations raise the possibility that platelet aggregation abnormalities in thrombobytopenic disorders (may be obscured by (1) preparation artefacts and/or (2) artificially increasing platelet counts for in vitro studies.

A Novel Low Cost Technique to Perform Concurrent Topside and Backside Analysis of a Bare Die

2011 ◽  
Author(s):  
Raj Kabadi ◽  
Win Thandar Swe
Keyword(s):  
Failure Analysis ◽  
Printed Circuit Board ◽  
Low Cost ◽  
Circuit Board ◽  
Small Scale ◽  
Cover Slip ◽  
Printed Circuit ◽  
Glass Cover ◽  
Glass Cover Slip ◽  
Bond Pads

Abstract A novel low cost technique to facilitate concurrent topside and backside imaging of a bare die for optical fault localization purposes is presented. The technique overcomes the restrictions posed by unavailability of a suitable package or limited choices that may be present at a small scale packaging lab. The difficulties imposed on backside preparation of commonly used ceramic packages are overcome by providing an alternative that is relatively less expensive and easier to implement. This is accomplished by mounting the bare die on a glass cover slip using a suitable adhesive and wire bonding the bond pads to a specially designed printed circuit board. This method is being successfully utilized on multiple failure analysis requests received in our lab.

X-ray observations on wairakite and non-cubic analcime

1955 ◽  
Vol 30 (230) ◽  
pp. 699-708 ◽  
Author(s):  
D. S. Coombs
Keyword(s):  
Small Diameter ◽  
Personal Communication ◽  
Present Writer ◽  
New Mineral ◽  
X Ray ◽  
Cover Slip ◽  
Glass Cover ◽  
Glass Cover Slip ◽  
Cubic Forms ◽  
Ray Methods

Mr. A. Steiner has kindly invited the present writer to study by X-ray methods the new mineral wairakite described by him in the preceding pages. The material provided includes an incomplete octahedron 15 ram. across with small modifying ieositetrahedron-like faces, and some smaller partial icositetrahedra. Faces are dull and give diffuse reflections oil the optical goniometer, but, by attaching small pieces of glass cover-slip to improve the reflections, interfacial angles approximating to those of the cubic forms {111} and {211} were measured. As pointed out by Mr. Steiner, however, the mineral is birefring'ent, biaxial, and finely twinned. A preliminary small-diameter X-ray powder photograph taken by Mr. N. Wells of the Soil Bureau, Wellington, showed an apparently cubic, analeime-like pattern (personal communication).

scholarly journals Nonreversible loss of platelet aggregability induced by calcium deprivation

Blood ◽  
1978 ◽  
Vol 52 (3) ◽  
pp. 505-513 ◽  
Author(s):  
MB Zucker ◽  
RA Grant
Keyword(s):  
Platelet Rich Plasma ◽  
Shape Change ◽  
Divalent Cations ◽  
Chelating Agent ◽  
Serotonin Release ◽  
Clot Retraction ◽  
Irreversible Loss ◽  
Prolonged Incubation ◽  
Platelet Aggregability ◽  
Ph Dependent

Abstract Platelets lose their ability to aggregate when deprived of divalent cations. This usually was studied by incubating human citrated platelet- rich plasma with EDTA or EGTA and then adding enough CaCl2 to combine with the chelating agent. Incubation for 5–7 min at 37 degrees C caused irreversible loss of the platelets' ability to adhere to glass and to aggregate with ADP, epinephrine, A23187, vasopressin, or serotonin or upon rewarming after chilling and markedly reduced aggregation with collagen or thrombin. Control samples incubated with saline, CaEDTA, or CaEGTA were not inhibited. Untreated platelets washed and incubated in solutions treated with resins that remove divalent cations lost their ability to aggregate in 30 min. More than about 0.26 mM Mg2+ partially protected the platelets. Unlike aggregation, ADP-induced shape change, clot retraction caused by thrombin or ADP plus reptilase, and thrombin- induced 14C-serotonin release were not inhibited after incubation. Aggregability was not restored by prolonged incubation with CaCl2, adding normal plasma, or washing the platelets. Its loss was temperature and pH dependent, occurring in 2 min at 43 degrees C but not in 7 min at 30 degrees C, and at pH 7.8 but much less at pH 7.2. The defect was not associated with an increase in platelet cyclic AMP, a decrease in metabolic ATP, or the presence of free ADP.

scholarly journals The oxygen to iron ratio of oxychlorocruorin and the total quantity of oxygen carried by the pigment in spirographis

1934 ◽  
Vol 115 (794) ◽  
pp. 368-373 ◽  
Keyword(s):  
Wide Distribution ◽  
Distilled Water ◽  
Total Oxygen ◽  
Cover Slip ◽  
Biological Station ◽  
Glass Cover ◽  
Oxygen Capacity ◽  
Glass Cover Slip ◽  
Invertebrate Animals ◽  
Iron Analysis

There exist four respiratory pigments capable of uniting with oxygen in such a manner that the oxygen is given up to a vacuum. Of these four, hæmoglobin has a wide distribution in verterbrate and invertebrate animals (Redfield, 1933), chlorocruorin is found only in certain polychaete worms (Fox, 1926, 1932, 1933), hæmerythrin in sipunculid worms (Florkin, 1933) and hæmocyanin in arthropods and molluscs (Redfield, 1934). The first three pigments named contain iron in the molecule, while the last has copper. Since the work of Peters (1912) it has been known that in oxyhæmocyanin Dhéré (1916, 1919) first showed the approximate proportionality between the oxygen and copper contents, and later Begemann (1924), Redfield, Coolidge, and Montgomery (1928) and Guillemet and Gosselin (1932) established the ratio of one molecule of labile oxygen to two atoms of copper. For oxyhæmerythrin it has recently been shown by Florkin (1933) that one molecule of oxygen is united to three atoms of iron. Up to the present, however, the ratio of oxygen to iron in oxychlorocruorin has not been known, and the work reported below was undertaken to settle this question. The quantity of iron present in the blood of spirographis spallanzanill , both combined with chlorocruorin and free, has been analysed, and, the total oxygen capacity of the blood being known, the oxygen to iron ratio of oxychlorocruorin has been determined. For iron analysis pure undiluted blood was extracted from the crown of Spirographis at the Tamaris Marine Biological Station. The technique already described (Roche and Fox, 1933) was used for obtaining the blood, with this difference, that the crown was amputated by means of a glass cover-slip so that no iron instrument came into contact with the blood. Eight measured specimens (0.2 cc each) of blood, each derived from several individual worms, were diluted with distilled water and sealed in test tubes.

Effects Of Altered pH And Sodium Concentration On The Response Of Megakaryocytes And Platelets To ADP

1981 ◽  
Author(s):  
R M Leven ◽  
V T Nachmias
Keyword(s):  
Platelet Rich Plasma ◽  
Shape Change ◽  
Gel Filtration ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Sodium Concentration ◽  
Sodium Influx ◽  
A 23187 ◽  
Ruffled Border ◽  
Extracellular Sodium

By using both megakaryocytes and platelets to study effects of adenosine diphosphate (ADP), we hope to understand the ionic events underlying the shape changes induced by this nucleotide. Guinea pig bone marrow megakaryocytes were isolated to 50-90% purity by modifications of published procedures, and cultured for 12-48 hours. In response to ADP (l-10μM) megakaryocytes develop a ruffled border and spread in 15-30 minutes to 2-3 times their original diameter and adhere strongly to the substrate. Several other diphosphonuc1eotides or adenosine monophosphate have no effect. Spreading occurs in calciummagnesium free Hank’s salt solution, but is blocked when extracellular sodium was replaced by potassium, choline, or lithium. Amiloride, an inhibitor of sodium uptake, inhibits the extent of spreading 90% at 10-4M, but allows partial spreading in 60% of the cells. Spreading can be mimicked by incubating the cells with 2μM A-23187 combined with either 5mM methylamine or 1μM monensin, but not by A-23187 alone.The rate of platelet shape change was measured spectro- photometrical1y at 37°C with 5mM EGTA both in platelet rich plasma (PRP) or after gel filtration in phosphate buffered saline. Amiloride inhibits shape change completely at 1mM and 50-60% at 0.1mM, but only if present during gel filtration. A rapid drop in buffer pH from 7.4 to 6.9 causes a 50% inhibition of rate of shape change in PRP or after gel filtration, but the inhibition spontaneously reverses within three minutes incubation at the lower pH.These results are compatible with a model in which ADP causes a sodium influx which is linked to a change in intracellular pH. This may be a necessary but not necessarily sufficient step in ADP induced shape change.

scholarly journals Nonreversible loss of platelet aggregability induced by calcium deprivation

Blood ◽  
1978 ◽  
Vol 52 (3) ◽  
pp. 505-513 ◽  
Author(s):  
MB Zucker ◽  
RA Grant
Keyword(s):  
Platelet Rich Plasma ◽  
Shape Change ◽  
Divalent Cations ◽  
Chelating Agent ◽  
Serotonin Release ◽  
Clot Retraction ◽  
Irreversible Loss ◽  
Prolonged Incubation ◽  
Platelet Aggregability ◽  
Ph Dependent

Platelets lose their ability to aggregate when deprived of divalent cations. This usually was studied by incubating human citrated platelet- rich plasma with EDTA or EGTA and then adding enough CaCl2 to combine with the chelating agent. Incubation for 5–7 min at 37 degrees C caused irreversible loss of the platelets' ability to adhere to glass and to aggregate with ADP, epinephrine, A23187, vasopressin, or serotonin or upon rewarming after chilling and markedly reduced aggregation with collagen or thrombin. Control samples incubated with saline, CaEDTA, or CaEGTA were not inhibited. Untreated platelets washed and incubated in solutions treated with resins that remove divalent cations lost their ability to aggregate in 30 min. More than about 0.26 mM Mg2+ partially protected the platelets. Unlike aggregation, ADP-induced shape change, clot retraction caused by thrombin or ADP plus reptilase, and thrombin- induced 14C-serotonin release were not inhibited after incubation. Aggregability was not restored by prolonged incubation with CaCl2, adding normal plasma, or washing the platelets. Its loss was temperature and pH dependent, occurring in 2 min at 43 degrees C but not in 7 min at 30 degrees C, and at pH 7.8 but much less at pH 7.2. The defect was not associated with an increase in platelet cyclic AMP, a decrease in metabolic ATP, or the presence of free ADP.

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