Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DIPYRIDAMOLE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed1985

Modulation of the activity of PALA by dipyridamole.

PALA is thought to inhibit an early step in de novo pyrimidine synthesis, causing depletion of intracellular pyrimidine nucleotides. Dipyridamole, a nucleoside transport inhibitor which can block restoration of nucleotide levels via the salvage pathway, was tested for its ability to augment the cytotoxicity of PALA against normal and malignant human cells in vitro. At the clinically relevant concentration of 1 microM, dipyridamole increased the cytotoxicity of PALA against a melanoma, a colon carcinoma, a promyelocytic leukemia (HL-60), and normal marrow (CFU-GM) in clonogenic assays. Dipyridamole produced 50% inhibition of uridine uptake in these cells at concentrations of less than 0.1 microM and reduced the LD50 of PALA by approximately 50% in mice. These results indicate that dipyridamole can markedly potentiate the activity of PALA in vitro and in vivo.

Animals↗
PubMed1977

The effect of intravenous adenosine diphosphate on the number of circulating platelets in experimental animals: inhibition by prostaglandin E1, dipyridamole, SH-869 and VK-774.

The number of circulating platelets was monitored in anaesthetized animals by a continuous flow technique, using a Technicon Autocounter. Intravenous infusions of adenosine diphosphate (ADP) produced transient, dose-dependent falls in circulating platelet numbers in rabbits, dogs, rats, pigs and squirrel monkeys. The rat was the most sensitive of the species investigated. In the rabbit, the effect of a submaximal dose of ADP was inhibited in a dose-dependent manner by intravenous infusions of prostaglandin E1 (PGE1), dipyridamole, and two derivatives of dipyridamole (SH-869 and VK-774). The dose-response curves for PGE1, SH-869 and VK-774 were approximately parallel, whereas that for dipyridamole was considerably less steep. PGE1 was the most potent inhibitor, but the duration of action was very short. Dipyridamole and SH-869 produced inhibition of long duration. The duration of action of VK-774 was intermediate. All inhibitors produced marked and often long-lasting hypotension. The fact no inhibition of ADP effects could be demonstrated with dibenzyline and hexamethonium, which also produced marked hypotension of long duration, indicated that inhibition of the ADP effect by the four antagonists studied was not due to changes in blood pressure.

Adenosine Diphosphate↗
PubMed1979

Dipyridamole levels in plasma of man and other species.

Measurements were made of the concentration of dipyridamole in the plasma of man, dogs, pigs, and pigeons at different times after oral administration of the drug. In dogs and in man, there was considerable variation in the plasma levels of the drug in different subjects. Pigs and pigeons always had much lower levels of the drug in plasma than did men and dogs given comparable doses. After intravenous injection of dipyridamole to pigs, a large proportion of the drug appeared to leave the plasma almost immediately; subsequently, the half-life of the drug remaining in the plasma was quite similar to that previously reported in man. The administration of aspirin with dipyridamole sometimes resulted in higher blood levels of the drug in dogs, man, and pigs, but the effects were small. The wide variations in plasma drug levels observed indicate that in future human or experimental trials designed to evaluate the antithrombotic effect of dipyridamole, plasma levels of the drug should be routinely monitored.

Administration, Oral↗
PubMed1982

Dipyridamole is an interferon inducer.

2,6-Bis(diethanolamino)-4,8-dipiperidinopyrimido-[5,4-d]-pyrimidine (dipyridamole) induced interferon production in vitro in explanted mouse peritoneal leukocytes and to a lower degree in non-lymphoidal cell cultures of mouse (L cells primary embryo fibroblasts) and human (diploid embryo lung fibroblasts) origin. Dipyridamole induced interferon also in mice after intravenous administration. Peak interferon levels in the blood (128 IU/ml) were attained at 49 hr after injection of 0.1 mg dipyridamole per kg body weight and at 24 and 12 hr after injection of 0.6-1.8 and 16.7 mg/kg respectively. By its pH stability, thermostability and antigenic properties the interferon induced in mice, mouse peritoneal leukocytes and L cells corresponded to IFN-alpha and IFN-beta. This interferon-inducing capacity of dipyridamole may account for its broad-spectrum antiviral effect.

Animals↗
PubMed1983

[How dangerous is the dipyridamole test?].

In 203 patients with clinical symptoms of coronary artery disease, cardiac and extracardiac side effects of the dipyridamole test were investigated. Following dipyridamole (0.75 mg/kg body wt. i.v.), heart rate increased significantly, whereas arterial blood pressure remained almost constant. Dyspnea was noted in 80 cases (40.5%). In 48 patients (23.6%) rhythm disturbances were recorded; 58.1% suffered from extracardiac side effects such as congestion in the head, vertigo, heaviness of arms and legs, sensations of heat, upper abdominal pain, and nausea. A detailed report is given of 4 cases with extraordinary symptoms during or after the injection of dipyridamole. A life-threatening status anginosus with dyspnea, ST-segment elevation, and cardiac arrhythmia was observed in one of these cases. High-dose dipyridamole cannot be considered to be harmless. The test should not be performed without continuous ECG monitoring and other safety measures.

Adult↗
PubMed1978

Potentiation by dipyridamole of the inhibition of guinea-pig ileum twitch response caused by adenine derivatives.

The inhibition actions of adenosine and adenine nucleotides, such as ATP, AMP and cyclic AMP, on contractions of guinea-pig from ileum induced by transmural stimulation were potentiated by dipyridamole, whereas those of inosine, morphine and tetrodotoxin were not affected. Tritium activity, accumulated during incubation of the ileal segments with [3H]adenosine, was reduced by dipyridamole. The adenosine added was degraded to inosine and then hypoxanthine during incubation, with the ileal segments, thereby restoring the twitch response of the ileal segments. In the presence of dipyridamole, the degradation of adenosine and the recovery of the twitch response was retarded. Thus, dipyridamole may potentiate the inhibitory actions of adenosine and adenine nucleotides on the twitch response of the ileum by inhibiting both the accumulation and the degradation of adenosine.

Adenine Nucleotides↗
PubMed1980

Platelet release reaction in vivo in patients with ischaemic heart disease after isometric exercise and its prevention with dipyridamole.

In 20 patients with ischaemic heart disease (IHD), platelet sensitivity to ADP-aggregation, plasma von Willebrand factor (vWF) and plasma beta-thromoboglobulin (beta-TG) were measured before and after isometric exercise. Effect of dipyridamole on these determinants was studied in a crossover fashion. To assess plasma vWF level, a new simple method was employed which has the advantage of not requiring an optical aggregometer and was proved to be reproducible. No significant difference was seen in platelet sensitivity to ADP-aggregation, vWF and beta-TG among healthy controls, IHD patients on placebo and on dipyridamole at rest. After exercise, platelet sensitivity to aggregation, plasma vWF and beta-TG increased significantly in IHD patients on placebo. In healthy controls, no significant changes were seen. On dipyridamole, above changes seen in IHD patients were not seen. The results suggests that isometric exercise may induce platelet release reaction in vivo and may produce hypercoagulable state in IHD patients. These phenomena may be prevented by pretreatment with dipyridamole.

Adult↗
PubMed1981

[Two cases with the heart murmur originated from aortocoronary bypass: the diagnostic use of dipyridamole (author's transl)].

Two cases with the heart murmurs considered to be caused by aortocoronary (A-C) bypass surgery were reported. Case 1: A systolic and an early and late diastolic murmurs were noted following A-C bypass surgery. The murmurs were located at the second left intercostal space. After methoxamine, the systolic and early diastolic murmurs increases slightly in intensity, while the late diastolic murmur did not change. Amyl nitrite inhalation slightly increased the intensity of the systolic murmur, but did not that of the diastolic murmur. Dipyridamole injection at a rate of 0.142 mg/kg/min resulted in the increase of both systolic and diastolic murmurs. Case 2: A diastolic murmur was noted following the bypass surgery, which was situated over the fourth left intercostal space, 4 cm outside from the left sternal border. Methoxamine injection intensified the murmur. The murmur was not affected by amyl nitrite. After dipyridamole injection, the murmur was slightly intensified. Dipyridamole is known to dilate coronary vessels without affecting appreciably the systemic circulation. In these two cases, the murmur noted following A-C bypass surgery was increased with dipyridamole, suggesting clinical applicability of this drug in ascertaining the bypass flow murmur.

Coronary Artery Bypass↗
PubMed1982

The effect of dipyridamole on experimentally induced stress ulcers.

Several doses of dipyridamomle were tested to assess a reduction in gastric bleeding and ulcer formation in rats exposed to cold stress restraint. When saline was compared to 12.5 mg/kg dipyridamole and 50 units/kg heparin, dipyridamole was significantly better than saline controls (P less than 0.05) in the reduction of both gastric bleeding and gastric ulceration, while the effects of heparin were not significant in either case. Finally, mean hematocrit, platelet count, and gastric acid secretion were not significantly affected by the dose of dipyridamole used (12.5 mg/kg). The results of this study show dipyridamole to be useful in the reduction of both stress ulceration and gastric bleeding induced in rats by cold stress restraint.

Animals↗
PubMed1981

[Clinical usefulness of thallium-201 myocardial scintigraphy with dipyridamole pharmacodynamic test in ischemic heart disease (author's transl)].

A clinical evaluation of the dipyridamole in the myocardial perfusional scintigraphy (MPS) was carried out in a series of patients, comprehensive of cases of unstable angina, aiming to assess the feasibility and diagnostic validity of the test and to state its possible role in comparison with exercise stress test. On the whole, 107 subjects were examined (34 with stable angina, 23 with unstable angina, 19 with recent myocardial infarction, 15 with atypical angina, 10 with chest pain of uncertain origin and 6 healthy volunteers), performing 108 scintigraphic studies (48 after dipyridamole infusion and 37 after bicycle exercise). In the studies with physical or pharmacologic stress a redistribution scintigraphy was also performed (4 hour after the injection). The dipyridamole stress test was well tolerated by patients with unstable angina too and showed a diagnostic sensitivity equivalent to that with exercise stress, although the latter appears better as regards image quality and can give an increase of sensitivity provided electrocardiographic findings are evaluated. Post-stress redistribution of 201 Tl in delayed scans was shown either after dipyridamole or after exercise in patients with typical angina without prior infarction. The computation, by the Bayes's theorem, of the predictive value of the two tests leads the Authors to the following conclusions: in atypical angina (prevalence of CAD: about 40%) the association MPS + exercise ECG is preferable; in patients with chest pain of uncertain origin or with asymptomatic electrocardiographic alterations (prevalence of CAD: about 15%) it is better to take into account only the scintigraphic findings obtained after exercise or pharmacologic stress, to avoid an excess of false positive results.

Angina Pectoris↗
PubMed1981

Effect of aspirin and dipyridamole on the interaction of human platelets with sub-endothelium: studies using citrated and native blood.

The effect of aspirin and dipyridamole ingestion on the interaction of platelets with the subendothelium was studied using both citrated blood and directly sampled (native) blood. After obtained control studies, normal human subjects ingested 0.6 g of aspirin, 150 mg of dipyridamole, or a placebo and studies were repeated 1 1/2 hrs later. Subjects continued on placebo, aspirin (0.6 g b.i.d.) or dipyridamole (100 mg q.i.d.) for 6 days and studies were obtained 1 1/2 hrs after the last dose. Blood was circulated through an annular chamber on whose inner core were mounted everted segments of de-endothelialized rabbit aorta. The wall shear rate was 2,600 sec(-1). Surface coverage with adherent platelets and platelet thrombi, as well as several parameters of thrombus dimensions, were evaluated morphometrically. Aspirin ingestion markedly reduced platelet thrombi in citrated blood,--but had a much lesser inhibitory effective in native blood. Platelet adhesion was unaffected in native blood, in contrast to previous findings in which a lower shear rate (800 sec (-1)) was used. Ingestion of dipyridamole did not inhibit platelet adhesion or thrombi in either citrated or native blood. The studies indicated that, with the flow conditions used, aspirin is a relatively weak inhibitor of platelet thrombus formation in directly sampled human blood.

Adult↗
PubMed1981

[Value of dipyridamole test in the diagnosis of ischemic heart disease].

The diagnostic test with dipyridamol was carried out in 83 patients with ischaemic heart disease (IHD) and cardialgias of various genesis, with diagnosis verified by coronarography and veloergometry. IHD patients after dipyridamol had angina pectoris attacks with or without ischaemic changes on ECG, which points to latent coronary insufficiency. The appearance of an anginal attack with the depression of the ST segment is typical of IHD with stenosing coronary atherosclerosis, as a rule, with developed collateral vessels. As to sensitivity and specificity in detecting IHD the dipyridamol test is equal to the bicycle ergometry tests. With the results of both tests considered the frequency rate of detection of IHD is increased. The dipyridamol test is recommended for diagnosis of IHD in therapeutic and cardiological hospitals.

Adult↗
PubMedDate not supplied

Prevention of deep venous thrombosis and thrombo-embolism by dipyridamole and acetylsalicylic acid after reconstructive arterial surgery.

A series of 400 consecutive patients subjected to reconstructive arterial surgery were randomly allocated into four equal groups in order to study the effect of dipyridamole and acetylsalicylic acid (ASA) in the prevention of deep venous thrombosis and pulmonary embolism. There were 11 drop-outs. In the dipyridamole-ASA group there were no thrombotic complications while in the control group without antithrombotic therapy five cases of deep venous thrombosis and two cases of fatal pulmonary embolism were encountered (p < 0.05). In the groups receiving either dipyridamole or ASA alone two and four cases of deep venous thrombosis, respectively, were found. It is concluded that treatment with dipyridamole and ASA combined is useful in preventing postoperative thrombotic complication after peripheral vascular reconstructive surgery.

Adolescent↗
PubMed1978

[The effect of dipyridamole on coagulation status in stenocardia].

The laboratory examination of Dipyridamole concerning its antiaggregation effect is presented in the paper. Thirty patients with coronary insufficiency have been taking Dipyridamole for one year. The average dosage was four pills à 75 mg of Dipyridamole a day. The aggregation and adhesion of the platelets with the examined patients was checked before and during the treatment. The inhibition platelet aggregation with Dipyridamole has been confirmed in vitro.

Adult↗
PubMed1995

[ECG-dipyridamole and ECG-exercise test in the assessment of ischemic cardiopathy: effects of the acute administration of nitroglycerin].

It is known that intravenous administration of dipyridamole can induce chest pain and ECG signs of ischemia in patients with coronary artery disease. In the present study we evaluated ECG and hemodynamic changes in response to dipyridamole (0.56 mg/kg in 10 min) under basal conditions and 3 hours after administration of nitroglycerin (10 mg/24 h patch) in 14 patients with coronary artery disease. The effects of nitroglycerin were also compared to those induced by the same drug on a bicycle stress test in the same patients. Exercise stress test induced specific ST changes in all patients when performed off-drug. Nitroglycerin administration completely prevented exercise-induced ischemia in 2 patients, and significantly prolonged exercise time in the remaining patients (p < 0.01). This effect was accompanied by a significant increase in heart rate (HR) and rate-pressure product at the threshold of ischemia (HRBP, p < 0.01); furthermore we observed a significant increase in HR at the maximal work load (p < 0.05). In the absence of treatment, dipyridamole infusion induced ST segment changes and/or typical chest pain in 12/14 patients. Moreover we observed a significant increase (p < 0.05) in HR, BP and HRBP during the test with respect to basal conditions. Following nitroglycerin administration, dipyridamole infusion failed to induce ischemia in 4 patients, and the time to ST depression in the remaining 8 patients (459 +/- 69 vs 610 +/- 127 s; p < 0.05) was significantly prolonged.(ABSTRACT TRUNCATED AT 250 WORDS)

Dipyridamole↗
PubMedDate not supplied

Diagnosis of coronary artery disease using dipyridamole thallium-201 imaging.

Dipyridamole thallium-201 imaging, using single-photon emission computed tomography, was evaluated for its safety and diagnostic efficacy in 109 patients with angiographically documented coronary artery disease and 35 normal subjects. The most common side effects after the intravenous administration of dipyridamole thallium-201 (0.56 mg/kg) included chest pain in 41 patients, dizziness in 20 patients, headache in 16 patients, and ST segment depression > or = 1 mm in 15 patients. Aminophylline was required to reverse the side-effects in 46 patients, and 45 of the 46 patients experienced complete relief of symptoms. Of the 109 patients with coronary artery disease, 104 had abnormal dipyridamole thallium images. The per patient sensitivity was 95%. Of the 35 normal subjects, 27 had normal thallium images. The per patient specificity was 77%. The sensitivity and specificity for the individual vessels were 84% and 87% for the left anterior descending artery, 67% and 97% for the left circumflex artery, and 89% and 85% for the right coronary artery, respectively. Dipyridamole thallium-201 imaging is a relatively safe noninvasive method and is an effective alternative to exercise thallium-201 scintigraphy for the diagnosis of coronary artery disease.

Aged↗
PubMed1995

Serial myocardial perfusion imaging with dipyridamole and rubidium-82 to assess restenosis after angioplasty.

UNLABELLED: The purpose of this study was to determine whether patients at high risk for clinical restenosis, following coronary angioplasty, could be identified by myocardial perfusion imaging performed with dipyridamole- 82Rb PET. METHODS: Forty-five patients (34 men, 11 women; mean age 58.5 yr) who had successful single-vessel angioplasty and were asymptomatic had dipyridamole-82Rb PET at 1 and 3 mo after the procedure. Abnormal flow reserve in the distribution of the angioplasty artery on PET was considered to be a decrease of > or = 1 perfusion grade in response to dipyridamole (assessed qualitatively from tomographic images and polar coordinate maps). Follow-up was performed for 6 mo postangioplasty. Clinical restenosis was defined as recurrent angina similar to that occurring before angioplasty and/or > or = 50% stenosis at the angioplasty site documented angiographically. We analyzed abnormal flow reserve in the distribution of the angioplasty vessel to identify which patients were at high risk for clinical restenosis. RESULTS: Fourteen patients developed clinical restenosis between 1 and 6 mo postangioplasty. Abnormal relative flow reserve in the distribution of the angioplasty vessel was present prior to the development of symptoms in 13 of 14 patients with clinical restenosis and in 8 of 31 patients without clinical restenosis (sensitivity 93%, specificity 74%, p < 0.0001). PET imaging successfully separated postangioplasty patients into groups with high (62%) and low (4%) risk of clinical restenosis. CONCLUSION: Abnormal relative flow reserve in the distribution of the angioplasty vessel on dipyridamole PET identifies asymptomatic postangioplasty patients at risk for clinical restenosis.

Angioplasty, Balloon, Coronary↗
PubMed1995

Prognostic significance of increased thallium-201 lung uptake during dipyridamole myocardial scintigraphy: comparison with exercise scintigraphy.

OBJECTIVE: To compare the incidence of cardiac events among patients with increased lung uptake of thallium after dipyridamole stress, matched subjects without such uptake and matched subjects with increased lung uptake during exercise stress. DESIGN: Retrospective case control study based on quantitative and semiquantitative visual consensus analysis of thallium scintigraphy. SETTING: Nuclear cardiology laboratory of a university teaching hospital. PATIENTS: Thirty-six patients with increased lung activity after dipyridamole stress and two groups of matched control subjects identified from 3150 consecutive thallium single photon emission computed tomography studies. INTERVENTIONS: Telephone follow-up and chart reviews to determine the incidence of cardiac events. MAIN RESULTS: Cardiac events were significantly less frequent in the study group with increased lung uptake after dipyridamole stress (two of 36,5%) than in the control group with increased thallium lung uptake at exercise scintigraphy (nine of 36,25%; P = 0.046). CONCLUSIONS: Increased lung uptake of thallium has less ominous short term prognostic significance when observed in association with dipyridamole stress rather than with exercise.

Aged↗