persantine 25mg tabs
The choice of hemopoietic differentiation by polypotent bone marrow stem cells was studied by morphological and chemiluminescent methods. This choice occurred on day 7 after heterotopic bone marrow transplantation and dipyridamole administration, under the effect of oxidative homeostasis imbalance in the plasma. Dipyridamole increased total antioxidant activity and 10-fold reduced the intensity of free radical oxidation. Disaggregation therapy with dipyridamole reduced platelet count in the peripheral blood and decreased total plasma antioxidant activity.
persantine 10 mg
Patients were stratified according to time after transplantation (group I, up to 2 years after transplantation; group II, 2 to 4 years after transplantation; group III, more than 4 years after transplantation). Changes of the diameter of proximal, mid and distal segments of the left anterior descending coronary artery and the circumflex branch of the left coronary artery were investigated after endothelium-dependent and endothelium-independent stimulation with acetylcholine (ACh, 50 and 100 micrograms i.c.) and nitroglycerin 0.3 mg i.c. Coronary flow changes were assessed endothelium-dependently (ACh 50 and 100 micrograms i.c.) and endothelium-independently (dipyridamole 0.56 mg/kg i.v.) utilizing an 8 F Judkins-style Doppler catheter.
persantine 75 mg
The activity of volume-sensitive Cl- channels was studied in human tracheal epithelial cells (9HTEo-) by taurine efflux experiments. The efflux elicited by a hypotonic shock was partially inhibited by adenosine receptor antagonists, by alpha,beta-methyleneadenosine 5'-diphosphate (alphabetaMeADP), an inhibitor of the 5'-ectonucleotidase, and by adenosine deaminase. On the other hand, dipyridamole, a nucleoside transporter inhibitor, increased the swelling-induced taurine efflux. Extracellular ATP and adenosine increased taurine efflux by potentiating the effect of hypotonic shock. alphabetaMeADP strongly inhibited the effect of extracellular ATP but not that of adenosine. These results suggest that anion channel activation involves the release of intracellular ATP, which is then degraded to adenosine by specific ectoenzymes. Adenosine then binds to purinergic receptors, causing the activation of the channels. To directly demonstrate ATP efflux, cells were loaded with [3H]AMP, and the release of radiolabeled molecules was analyzed by high performance liquid chromatography. During hypotonic shock, cell supernatants showed the presence of ATP, ADP, and adenosine. alphabetaMeADP inhibited adenosine formation and caused the appearance of AMP. Under hypotonic conditions, elevation of intracellular Ca2+ by ionomycin caused an increase of ATP and adenosine in the extracellular solution. Our results demonstrate that volume-sensitive anion channels are regulated with an autocrine mechanism involving swelling-induced ATP release and then hydrolysis to adenosine.
Human adipocytes are of limited viability (7 +/- 2% release of lactate dehydrogenase/h) and contain active ectophosphatases which are capable of sequentially degrading ATP to adenosine. At densities of 30,000-40,000 cells/ml, human fat cell suspensions accumulated adenosine, inosine, and hypoxanthine, and their concentrations were 38 +/- 8, 120 +/- 10, and 31 +/- 7 nmol/liter after 3 h of incubation. Dipyridamole (10 mumol/liter), an inhibitor of nucleoside transport, caused a 5-7-fold increase in adenosine accumulation which was reduced by 85% on inhibition of ectophosphatases by beta-glycerophosphate and antibodies against ecto-5'-nucleotidase or alpha, beta-methylene 5'-adenosine diphosphate (10 mumol/liter), respectively, indicating that most of the adenosine is produced in the extracellular compartment. Accordingly, the spontaneous accumulation of adenosine was reduced beyond 5 nmol/liter on inhibition of ectophosphatase activities or removal of extracellular AMP by AMP deaminase (4 units/ml). Added adenosine (30 nmol/liter) disappeared until its concentration approached 5 nmol/liter. Isoproterenol (1 mumol/liter) had no effect on adenosine accumulation regardless whether purine production from extracellular sources was minimized or not. In contrast to adenosine, the concentrations of inosine and hypoxanthine displayed only a modest decrease (30-50%) on inhibition of ectophosphatase activities. In addition, isoproterenol caused a 2-3-fold increase in inosine and hypoxanthine production which was concentration-dependent and could be inhibited by propranolol. It is concluded that the adenosine that accumulates in human adipocyte suspensions is almost exclusively derived from adenine nucleotides which are released by leaking cells. By contrast, inosine and hypoxanthine are produced inside the cells, and the release of these latter purines appears to be linked to ATP turnover via adenylate cyclase.
Both safety and usefulness of dobutamine-atropine stress in myocardial perfusion imaging have been reported. However, no information exists on whether the magnitude ofhyperemia achieved with dipyridamole and dobutamine-atropine is comparable.
persantine oral dose
The aim of this study was to investigate the relationship between QRS duration, artifactual perfusion abnormalities, and left ventricular function in patients with left bundle branch block (LBBB) using dipyridamole technetium-99m sestamibi electrocardiography-gated single-photon emission computed tomography (SPECT).
persantine generic names
For patients with recent myocardial infarction, the main determinants of prognosis are: extent of transmural necrosis, state of the infarct-related artery and the presence and extent of myocardium at risk. The basic principle underlying the use of stress echocardiography states that myocardial ischaemia produces abnormalities of regional wall motion which are by themselves early, sensitive and specific markers of decreased perfusion. Dobutamine infusion allows for evaluation of myocardial contractile reserve by increasing inotropism. In low doses it gives us information on regional viability. In high doses, wall motion under increased oxygen demand, it becomes dependent on the ability of the coronary arteries to increase blood flow. Dipyridamole induces coronary vasodilation. In low doses it produces an increase in the blood flow. In high doses the steal effect deviates blood from the regions dependent on stenosed arteries. Ischaemia and regional wall motion abnormalities ensue. A negative stress echocardiogram, either under dobutamine or dipyridamole, has an excellent negative predictive value while a positive stress echocardiogram is predictive of an increased rate of events in the follow-up.
persantine medication classification
The aim of this study was to investigate the influence of the manufacturing process on the physicochemical properties of three poorly water soluble compounds (carbamazepine, dipyridamole, and indomethacin) when processed with a polymer (polyvinylpyrrolidone K30 (PVP)) at a 1:2 drug to polymer ratio. Melt extrusion, spray drying, and ball milling techniques were used to prepare glass solutions. Product homogeneity, dissolution, physical stability, and drug/polymer interactions were investigated. Particular attention was paid to solid phase analysis using XRPD, modulated temperature DSC, optical microscopy, and Raman microscopy and the importance of using a combination of techniques was demonstrated. The latter technique when applied to freshly ball milled samples exhibited the presence of drug and polymer rich areas, indicating that complete glass solution formation had not occurred. The three compounds produced products with differing physical stability with indomethacin proving the most physically stable. These differences in physical stability were attributed to hydrogen bonding of drug and polymer. The manufacturing technique did not influence physical stability, but it did affect dissolution. The dissolution of the spray-dried material was generally poor, compared to melt extruded and ball milled products. This was probably due to rapid dissolution of PVP from the small particles of the spray-dried products.
The diagnostic value of myocardial perfusion scintigraphy in patients with left bundle branch block (LBBB) and previous acute myocardial infarction has not been evaluated.
persantine and alcohol
Measurements of the coronary sinus blood flow velocity with Doppler catheters (Medtronic Floscan; Millar DC201) were performed to assess coronary flow reserve and significance of coronary artery stenosis. In seven patients with normal coronary angiogram coronary sinus blood flow velocity (Doppler catheters) and coronary sinus blood flow volume (thermodilution) were simultaneously recorded. Coronary flow reserve was calculated as the quotient of the peak flow velocity (peak flow volume) and resting flow velocity (resting flow volume) after infusion of 0.5 mg/kg dipyridamole intravenously. The correlation coefficient was r = 0.88. Coronary sinus blood flow velocity was measured in 31 patients at resting conditions and after injection of contrast media during coronary angiography. At resting conditions blood flow velocity was 3.6 +/- 1.5 cm/s (n = 31), 3.5 +/- 1.8 cm/s (n = 9; controls), and 3.6 +/- 1.1 cm/s (n = 9; significant stenosis of the left anterior descending; not significant). After injection of contrast media flow velocity amounted to 2.2-fold resting flow in controls and to 1.5-fold resting flow in patients with stenoses of the left anterior descending artery (p less than 0.01). Measurement of coronary sinus blood flow velocity with Doppler catheters is a valuable adjunct for determination of coronary flow reserve and for assessment of stenosis severity of the left anterior descending artery. Continuous on-line monitoring of phasic flow velocity provides important information of the myocardial perfusion, e.g., during angioplasty.
persantine 25 mg
The basic aspect of cell behaviour that is the clue for viability recognition by stress echo is regional function. By definition, the function is depressed both in viable and in necrotic segments. However, only viable segments retain a contractile reserve; which can be evoked by an inotropic challenge, either cathecolaminic or flow-mediated, as consistently shown by several experimental studies. This is the basis of viability recognition by pharmacological stress echocardiography. Both dobutamine and dipyridamole exploit the same pathophysiological principle: viable tissue has a residual contractile reserve, which can be elicited by an appropriate inotropic stimulus. With dobutamine, the stimulus is a beta-receptor mediated effect on myocardial cell, which is later matched by an increase in flow. With dipyridamole, the primary stimulus is an adenosine A2-receptor mediated effect on the coronary arteriole smooth muscle cell, leading to an increase in flow. At that point, the increase in function is to be expected on the basis of the known relationship between myocardial contractility and coronary perfusion. From the technical point of view, the "viability window" is dose-related with dobutamine, and time-related with dipyridamole--where the same dose is associated to an early inotropic phase followed by a later ischemic response. In spite of the different pathophysiological background and technical modalities, dobutamine and and dipyridamole have shown a similar sensitivity and specificity for prediction of viability, with an overall accuracy only marginally lower than resting thallium. The practical, clinical impact of these observations is still blunted by relatively small numbers of observations in highly selected populations including a limited number of patients and studies in very few centers.(ABSTRACT TRUNCATED AT 250 WORDS)
persantine dosage chart
CAD defined as ≥70% stenosis was found in 152 patients (75%). During follow-up major adverse cardiovascular events (MACE) occurred in 109 (54%) patients (10 deaths, 16 infarctions, 83 revascularizations). The presence of inducible WMA in DSE was associated with high risk of MACE [hazard ratio (HR): 5.4; 95% CI: 3.64-8.05, P<0.0001]. Cardiovascular complications were best predicted by the presence of any inducible abnormality-PD or WMA (HR: 6.1; 95% CI: 4.1-9.1, P<0.0001).
persantine dose calculation
These results suggest that dipyridamole, a potent coronary vasodilator, produces maldistribution of coronary blood flow in our dog models, whereas sevoflurane does not do this in animal or human studies.
In an attempt to elucidate the types of nucleoside transporters present in bone marrow stem cells, this study examined the effect of nucleoside transport inhibitors on the toxicity of nucleoside analogs and on the salvage of thymidine by mouse bone marrow granulocyte and macrophage progenitor cells using the CFU-GM assay. Concentrations of NBMPR (nitrobenzylmercaptopurine riboside) as low as 10 nM protected these cells from the toxicity of the adenosine analog tubercidin and provided a partial block of thymidine-rescue of the granulocyte-macrophage progenitor cells from methotrexate toxicity. Dipyridamole had similar effects but generally required higher concentrations. These results suggested that the major nucleoside transporter in these cells is the NBMPR-sensitive equilibrative carrier, es. In contrast to the results with tubercidin, the toxicity of 2-chlorodeoxyadenosine was increased 8- to 10-fold by 1 microM NBMPR. These results suggested that the bone marrow granulocyte-macrophage progenitor cells also have a concentrative nucleoside transporter that is capable of pumping 2-chlorodeoxyadenosine into the cells while efflux of the nucleoside via es is blocked by NBMPR.
persantine brand name
Twenty-four patients with non-alcoholic fatty liver disease and 28 healthy subjects were studied. According to the pathology of liver biopsies, patients with non-alcoholic fatty liver disease were divided into non-alcoholic fatty liver and nonalcoholic steatohepatitis groups. Coronary diastolic peak flow velocities were measured at baseline, and then dipyridamole infusion was measured by transthoracic Doppler echocardiography. The ratio of hyperemic to baseline diastolic peak velocities was calculated and the intima-media thicknesss of the carotid arteries were measured.
Dipyridamole is a classic platelet inhibitor which has been a key medicine in clinical therapy of thrombosis and cerebrovascular disease. A rapid, selective and convenient method using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for determination of dipyridamole in human plasma. After protein precipitation of 200 microL plasma with methanol, dipyridamole and diazepam (internal standard) were chromatographed on an Ultimate XB-C(18) (50 x 2.1 mm i.d, 3 microm) column with the mobile phase consisting of methanol-ammonium acetate (5 mM; 80 : 20, v/v) at a flow rate of 0.25 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring mode via positive eletrospray ionization source (ESI(+)). The retention times of dipyridamole and diazepam were 1.4 and 1.2 min, respectively. The method was validated over a concentration range of 0.0180-4.50 microg/mL (r(2) > or = 0.99) with a lower limit of quantitation (LLOQ) of 0.0180 microg/mL for dipyridamole. The intra- and inter-day precisions (RSD) of the assay at all three QC levels were 1.6-12.7% with an accuracy (RE) of -4.3-1.9%, which meets the requirements of the FDA guidance. The HPLC-MS/MS method herein described was proved to be suitable for pharmacokinetic study of sustained-release dipyridamole tablet in volunteers after oral administration.
persantine generic name
Isolated longitudinal muscle strip with Auerbach's plexus attached was used to study the stimulation-evoked release of 3H-acetylcholine (3H-ACh) under normoxic and hypoxic conditions. Hypoxia reduced the release of ACh. Theophylline, a purinoceptor P1 antagonist and vinpocetine, an antiischemic compound partly reversed the effect of hypoxia. Unlike theophylline, the effect of vinpocetine was not mediated via adenosine action, since it failed to affect the presynaptic action of adenosine, and the effect of theophylline and vinpocetine was additive. When they were added together the effect of hypoxia was almost completely antagonized. Dipyridamole, an adenosine uptake inhibitor, potentiated the effect of hypoxia and the presynaptic inhibitory action of adenosine on ACh release. Evidence was obtained that the effect of hypoxia is at least partly due to adenosine formed from purine nucleotides.
More than 7 million stress perfusion studies are performed in the United States annually, 44% with pharmacological vasodilator stress agents. Both adenosine and dipyridamole are nonselective coronary vasodilators that are commonly used for stress perfusion imaging. These agents are safe and provide an effective means to diagnose coronary artery disease. A newer agent, regadenoson, is an adenosine receptor agonist that is selective for coronary vasodilation. Regadenoson is noninferior to adenosine for the detection of ischemia and is better tolerated by patients. Recent trials such as INSPIRE (Adenosine Sestamibi Post-Infarction Evaluation) and the COURAGE (Results from Clinical Outcomes Utilizing Revascularization and Aggressive Guideline-driven Drug Evaluation) Nuclear Imaging Substudy have established clearly that noninvasive risk stratification with vasodilator testing is an important and appropriate step in guiding medical therapy and invasive coronary intervention.
Cardiovascular calcification, the formation of calcium phosphate deposits in cardiovascular tissue, is a common endstage phenomenon affecting a wide variety of bioprostheses. The purpose of the present paper is to study the possibility that some antiplatelet drugs (aspirin and persantine) and certain vitamins (vitamin C, vitamin B6, and vitamin E) and their combinations might prevent the mineralization of glutaraldehyde treated bovine pericardium (GABP) by modifying the pericardial surface. In this experimental protocol, we used Golomb and Wagner's (1991) in vitro model for studying GABP calcification and a diffusion cell with 2 compartments for evaluating the diffusion of calcium across the GABP. The results showed that a combination of aspirin and vitamins (0.5 mg% aspirin, 1.5 mg% vitamin C, 4 mg% vitamin B6, and 2 mg% vitamin E) in a metastable calcium phosphate solution not only reduced the transport of calcium ions through GABP, but along with the combinations of 0.5 mg% aspirin and 5 mg% persantine also produced significant reductions in GABP calcification. The exact mechanism of these changes in the calcification of GABP are still unknown. From these in vitro findings, it appears that a combined vitamin therapy with low doses of aspirin may be beneficial for platelet suppression and thereby prevent thrombosis. In addition, the vitamins may modify calcium transport and interfere with the adsorption at the surface, thus reducing GABP calcification. However, an important question that remains unanswered is whether this inhibitory effect would continue if the antiplatelet drugs and vitamins were discontinued. For the answer, more in vivo studies are needed to develop applications.
persantine drug class
The purpose of this study was to compare myocardial contrast echocardiography (MCE) with single-photon emission computed tomography (SPECT) for the detection of significant coronary artery disease (CAD) in patients with symptoms suggestive of CAD.
persantine 50 mg
MCE, which is a bedside technique, may be used to detect CAD in patients presenting with AHF without a prior history of CAD or evidence of acute myocardial infarction. Quantitative MCE may further risk-stratify patients with AHF but no CAD.
persantine drug classification
A total of 103 patients with suspected or known stable coronary artery disease (CAD) underwent SPECT and accelerated high-dose dipyridamole (0.84 mg/kg intravenously for 4 minutes) atropine (up to 1 mg intravenously) stress real-time qualitative MCE. The presence of CAD was detected by coronary angiography.