scholarly journals Metabolic aspects of the secretion of stored compounds from blood platelets. The effect of NaF at different pH on nucleotide metabolism and function of washed platelets

1981 ◽  
Vol 194 (1) ◽  
pp. 187-192 ◽  
Author(s):  
E H Mürer ◽  
K Davenport ◽  
E Siojo ◽  
H J Day
Keyword(s):  
Time Course ◽  
Adenine Nucleotides ◽  
Blood Platelets ◽  
Fluoride Concentration ◽  
Indirect Evidence ◽  
Inhibitory Effect ◽  
Nucleotide Metabolism ◽  
Wide Range ◽  
And Function ◽  
Special Circumstances

The purpose of this study was to investigate the response of human blood platelets to fluoride at different pH. The results were as follows. (1) Fluoride induced secretion faster and at a lower concentration when pH was lowered. (2) Platelets exposed to 2 mM-fluoride at 0 degrees C at pH 5.3 underwent secretion when first pH and then temperature was raised, although no secretion was seen at 2 mM-fluoride concentration in the absence of the preincubation at low pH. (3) The concentration of [14C]ATP in platelets decreased steeply in response to fluoride before induction of secretion. Addition of antimycin blocked or partly inhibited secretion. Fluoride thus exerts an inhibitory effect on platelet glycolysis before induction of secretion. (4) Fluoride accumulated in the platelet pellet by a time course that preceded secretion. The accumulation was faster and greater at pH 6 than at 7.4. These four points are taken as indirect evidence that fluoride has to penetrate to the interior of the platelet to induce secretion. The activation takes place over a wide range of acid pH in contrast with induction of platelet function via the outside of the plasma membrane. In addition evidence is presented that the salvage pathway may under special circumstances play an important role in the re-synthesis of platelet adenine nucleotides.

Platelets, inflammation and tissue regeneration

2011 ◽  
Vol 105 (S 06) ◽  
pp. S13-S33 ◽  
Author(s):  
Alan Nurden
Keyword(s):  
Skin Diseases ◽  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Blood Stream ◽  
Cellular Growth ◽  
Biologically Active ◽  
Wide Range ◽  
The Central Nervous System ◽  
Membrane Budding ◽  
And Function

SummaryBlood platelets have long been recognised to bring about primary haemostasis with deficiencies in platelet production and function manifesting in bleeding while upregulated function favourises arterial thrombosis. Yet increasing evidence indicates that platelets fulfil a much wider role in health and disease. First, they store and release a wide range of biologically active substances including the panoply of growth factors, chemokines and cytokines released from α-granules. Membrane budding gives rise to microparticles (MPs), another active participant within the blood stream. Platelets are essential for the innate immune response and combat infection (viruses, bacteria, micro-organisms). They help maintain and modulate inflammation and are a major source of pro-inflammatory molecules (e.g. P-selectin, tissue factor, CD40L, metalloproteinases). As well as promoting coagulation, they are active in fibrinolysis; wound healing, angiogenesis and bone formation as well as in maternal tissue and foetal vascular remodelling. Activated platelets and MPs intervene in the propagation of major diseases. They are major players in atherosclerosis and related diseases, pathologies of the central nervous system (Alzheimers disease, multiple sclerosis), cancer and tumour growth. They participate in other tissue-related acquired pathologies such as skin diseases and allergy, rheumatoid arthritis, liver disease; while, paradoxically, autologous platelet-rich plasma and platelet releasate are being used as an aid to promote tissue repair and cellular growth. The above mentioned roles of platelets are now discussed.

Effects of ribose on cardiac metabolism and function in isoproterenol-treated rats

1983 ◽  
Vol 245 (5) ◽  
pp. H880-H886
Author(s):  
H. G. Zimmer ◽  
H. Ibel
Keyword(s):  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Systolic Pressure ◽  
Cardiac Metabolism ◽  
Left Ventricular ◽  
Nucleotide Metabolism ◽  
Nucleotide Biosynthesis ◽  
Ventricular Systolic Pressure ◽  
Adenine Nucleotide Metabolism ◽  
And Function

Continuous iv infusion of ribose for 5 h in unanesthetized and unrestrained rats treated with isoproterenol (25 mg/kg sc) further enhanced the available pool of 5-phosphoribosyl-1-pyrophosphate and the biosynthesis of adenine nucleotides in the myocardium. The increase in adenine nucleotide biosynthesis was of such an extent that the isoproterenol-induced decline of the ATP level (mumol/g) was attenuated after 5 h (isoproterenol + ribose infusion 4.0 +/- 0.2, n = 10; isoproterenol + NaCl infusion 3.5 +/- 0.1, n = 23; control 4.5 + 0.1, n = 38) and prevented after 24 h (isoproterenol + ribose infusion 4.6 +/- 0.3, n = 5; isoproterenol + NaCl infusion 3.2 +/- 0.1, n = 9). Ribose, however, did not affect the isoproterenol-elicited elevation of the adenosine 3',5'-cyclic monophosphate (cAMP) and glucose 6-phosphate content nor did it influence the decline in glycogen. Thus ribose acts primarily via elevation of the cardiac 5-phosphoribosyl-1-pyrophosphate pool. Measurements of hemodynamic parameters with an ultraminiature catheter pressure transducer in intact rats anesthetized with thiobutabarbital sodium revealed that ribose infusion for at least 3 h further enhanced the isoproterenol-elicited increase in left ventricular dP/dtmax by about 20% but did not influence appreciably the rise in heart rate and the fall in left ventricular systolic pressure. Since ribose did not affect the immediate hemodynamic alterations induced by isoproterenol, it appears that it exerts its hemodynamic effects via the pronounced influence on cardiac adenine nucleotide metabolism.

scholarly journals Alterations of Adenine Nucleotide Metabolism and Function of Blood Platelets in Patients With Diabetes

Diabetes ◽  
2007 ◽  
Vol 56 (2) ◽  
pp. 462-467 ◽  
Author(s):  
Anna Michno ◽  
Hanna Bielarczyk ◽  
Tadeusz Pawełczyk ◽  
Agnieszka Jankowska-Kulawy ◽  
Joanna Klimaszewska ◽  
...  
Keyword(s):  
Adenine Nucleotide ◽  
Blood Platelets ◽  
Nucleotide Metabolism ◽  
Adenine Nucleotide Metabolism ◽  
Patients With Diabetes ◽  
And Function

The Effect of Mitomycin C on Platelet Aggregation and Adenosine 3′, 5′-Monophosphate Metabolism

1978 ◽  
Vol 39 (01) ◽  
pp. 177-185 ◽  
Author(s):  
Shuichi Hashimoto ◽  
Sachiko Shibata ◽  
Bonro Kobayashi
Keyword(s):  
Platelet Aggregation ◽  
Cyclic Amp ◽  
Mitomycin C ◽  
Blood Platelets ◽  
Adenosine Diphosphate ◽  
Cellular Membrane ◽  
Adenyl Cyclase ◽  
Cyclic Amp Phosphodiesterase ◽  
Membrane Structure And Function ◽  
And Function

SummaryThe effect of Mitomycin C on aggregation, adenosine 3′, 5′-monophosphate (cyclic AMP) metabolism and reactions induced by thrombin was studied in rabbit platelets. Mitomycin C inhibited the platelet aggregation induced by adenosine diphosphate or thrombin. The level of radioactive cyclic AMP derived from 8-14C adenine or 8-14C adenosine increased after incubating intact platelets with Mitomycin G. Formation of radioactive adenosine triphosphate also increased though mitochondrial oxidation was not stimulated. Similar effect was observed also in rabbit liver. Mitomycin C failed to stimulate platelet adenyl cyclase but inhibited cyclic AMP phosphodiesterase in the absence of theophylline. In the platelets preincubated with Mitomycin C, thrombin-induced inhibition of adenyl cyclase, stimulation of membrane-bound cyclic AMP phosphodiesterase, and release of 250,000 dalton protein from platelet membranes were prevented. These results suggest that Mitomycin C will affect cellular membrane structure and function, and this extranuclear effect of Mitomycin C will lead to inhibition of aggregation in blood platelets.

The Platelet of the Newborn Infant – Adenine Nucleotide Metabolism and Release

1980 ◽  
Vol 43 (02) ◽  
pp. 099-103 ◽  
Author(s):  
J M Whaun ◽  
P Lievaart ◽  
Keyword(s):  
Newborn Infant ◽  
Adenine Nucleotide ◽  
Platelet Rich Plasma ◽  
Adenine Nucleotides ◽  
Newborn Infants ◽  
Specific Radioactivity ◽  
Nucleotide Metabolism ◽  
Breakdown Product ◽  
Term Infants ◽  
Adenine Nucleotide Metabolism

SummaryBlood from normal full term infants, mothers and normal adults was collected in citrate. Citrated platelet-rich plasma was prelabelled with 3H-adenine and reacted with release inducers, collagen and adrenaline. Adenine nucleotide metabolism, total adenine nucleotide levels and changes in sizes of these pools were determined in platelets from these three groups of subjects.At rest, the platelet of the newborn infant, compared to that of the mother and normal adult, possessed similar amounts of adenosine triphosphate (ATP), 4.6 ± 0.2 (SD), 5.0 ± 1.1, 4.9 ± 0.6 µmoles ATP/1011 platelets respectively, and adenosine diphosphate (ADP), 2.4 ± 0.7, 2.8 ± 0.6, 3.0 ± 0.3 umoles ADP/1011 platelets respectively. However the marked elevation of specific radioactivity of ADP and ATP in these resting platelets indicated the platelet of the neonate has decreased adenine nucleotide stores.In addition to these decreased stores of adenine nucleotides, infant platelets showed significantly impaired release of ADP and ATP on exposure to collagen. The release of ADP in infants, mothers, and other adults was 0.9 ± 0.5 (SD), 1.5 ± 0.5, 1.5 ± 0.1 umoles/1011 platelets respectively; that of ATP was 0.6 ± 0.3, 1.0 ± 0.1,1.3 ± 0.2 µmoles/1011 platelets respectively. With collagen-induced release, platelets of newborn infants compared to those of other subjects showed only slight increased specific radioactivities of adenine nucleotides over basal levels. The content of metabolic hypoxanthine, a breakdown product of adenine nucleotides, increased in both platelets and plasma in all subjects studied.In contrast, with adrenaline as release inducer, the platelets of the newborn infant showed no adenine nucleotide release, no change in total ATP and level of radioactive hypoxanthine, and minimal change in total ADP. The reason for this decreased adrenaline reactivity of infant platelets compared to reactivity of adult platelets is unknown.Infant platelets may have different membranes, with resulting differences in regulation of cellular processes, or alternatively, may be refractory to catecholamines because of elevated levels of circulating catecholamines in the newborn period.

Newborn Platelet Dysfunction: a Storage Pool and Release Defect

1976 ◽  
Vol 36 (01) ◽  
pp. 200-207 ◽  
Author(s):  
Donald G. Corby ◽  
Thomas F. Zuck
Keyword(s):  
Specific Activity ◽  
Platelet Rich Plasma ◽  
Adenine Nucleotides ◽  
Blood Platelets ◽  
Newborn Infants ◽  
Specific Radioactivity ◽  
High Dose ◽  
Platelet Dysfunction ◽  
Paired Samples ◽  
Normal Adults

SummaryPer cent aggregation, release and content of adenine nucleotides, and specific radioactivity were evaluated in citrated platelet-rich plasma (PRP) prepared from paired samples of maternal and cord blood. Platelets of newborn infants aggregated normally in response to high dose ADP (20 μM), strong collagen suspensions, and thrombin; however, when compared with PRP from the mothers or from normal adults, per cent aggregation in response to lower concentrations of ADP (2 μM), weak collagen, and part particularly epinephrine was markedly reduced. Nucleotide release after stimulation of the newborns’ PRP with the latter two inducers was also impaired. ATP and ADP content of the newborns’ platelets was also significantly less than that of their mothers or of normal adults, but specific activity was normal. The data suggest that the impairment of ADP release in the platelets of newborn infants is due to decreased sensitivity to external stimuli. Since metabolic ATP is necessary for the platelet release reaction, it is postulated that the platelet dysfunction results from a lack of metabolic ATP.

Chaperonin as the normal controls and pathological anti-stress response in the human reproductive system

2016 ◽  
pp. 126-129
Author(s):  
M. Makarenko ◽  
◽  
D. Hovsyeyev ◽  
L. Sydoryk ◽  
◽  
...  
Keyword(s):  
Reproductive System ◽  
Stress Proteins ◽  
Physiological Stress ◽  
Protein Complexes ◽  
Reproductive Function ◽  
Intercellular Signaling ◽  
Toll Like Receptors ◽  
Wide Range ◽  
Protein Functions ◽  
And Function

Different kinds of physiological stress cause mass changes in the cells, including the changes in the structure and function of the protein complexes and in separate molecules. The protein functions is determined by its folding (the spatial conclusion), which depends on the functioning of proteins of thermal shock- molecular chaperons (HSPs) or depends on the stress proteins, that are high-conservative; specialized proteins that are responsible for the correct proteinaceous folding. The family of the molecular chaperones/ chaperonins/ Hsp60 has a special place due to the its unique properties of activating the signaling cascades through the system of Toll-like receptors; it also stimulates the cells to produce anti- inflammatory cytokines, defensins, molecules of cell adhesion and the molecules of MHC; it functions as the intercellular signaling molecule. The pathological role of Hsp60 is established in a wide range of illnesses, from diabetes to atherosclerosis, where Hsp60 takes part in the regulation of both apoptosis and the autoimmune processes. The presence of the HSPs was found in different tissues that are related to the reproductive system. Key words: molecular chaperons (HSPs), Toll-like receptors, reproductive function, natural auto antibody.

Possession and Repetition

2012 ◽  
Vol 6 (1-3) ◽  
pp. 243-259 ◽  
Author(s):  
Yohan Yoo
Keyword(s):  
First Century ◽  
Daily Lives ◽  
Modern Times ◽  
Sacred Texts ◽  
New Methods ◽  
Wide Range ◽  
Lay Buddhists ◽  
Iconic Status ◽  
And Function ◽  
To Receive

This article demonstrates the need for the iconic status and function of Buddhist scripture to receive more attention by illuminating how lay Korean Buddhists try to appropriate the power of sutras. The oral and aural aspects of scripture, explained by Wilfred Cantwell Smith, provide only a limited understanding of the characteristics of scripture. It should be noted that, before modern times, most lay people, not only in Buddhist cultures but also in Christian and other traditions, neither had the chance to recite scriptures nor to listen to their recitations regularly. Several clear examples demonstrate contemporary Korean Buddhists’ acceptance of the iconic status of sutras and their attempt to appropriate the power and status of those sacred texts. In contemporary Korea, lay Buddhists try to claim the power of scriptures in their daily lives by repeating and possessing them. Twenty-first century lay believers who cannot read or recite in a traditional style have found new methods of repetition, such as internet programs for copying sacred texts and for playing recordings of their recitations. In addition, many Korean Buddhists consider the act of having sutras in one’s possession to be an effective way of accessing the sacred status and power of these texts. Hence, various ways of possessing them have been developed in a wide range of products, from fancy gilded sutras to sneakers embroidered with mantras.

The Art of Love Poetry

2018 ◽  
Author(s):  
Erik Gray
Keyword(s):  
Popular Culture ◽  
Cultural History ◽  
Literary Tradition ◽  
Love Poetry ◽  
Erotic Love ◽  
Wide Range ◽  
History Of ◽  
And Function ◽  
Meaning And Function ◽  
Comprehensive History

Love begets poetry; poetry begets love. These two propositions have seemed evident to thinkers and poets across the Western literary tradition. Plato writes that “anyone that love touches instantly becomes a poet.” And even today, when poetry has largely disappeared from the mainstream of popular culture, it retains its romantic associations. But why should this be so—what are the connections between poetry and erotic love that lead us to associate them so strongly with one another? An examination of different theories of both love and poetry across the centuries reveals that the connection between them is not merely an accident of cultural history—the result of our having grown up hearing, or hearing about, love poetry—but something more intrinsic. Even as definitions of them have changed, the two phenomena have consistently been described in parallel terms. Love is characterized by paradox. Above all, it is both necessarily public, because interpersonal, and intensely private; hence it both requires expression and resists it. In poetry, especially lyric poetry, which features its own characteristic paradoxes and silences, love finds a natural outlet. This study considers both the theories and the love poems themselves, bringing together a wide range of examples from different eras in order to examine the major structures that love and poetry share. It does not aim to be a comprehensive history of Western love poetry, but an investigation into the meaning and function of recurrent tropes, forms, and images employed by poets to express and describe erotic love.

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