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Biomedical subjects

Z Parvez

Publications and source records attributed to Z Parvez.

24 records · Page 2Linked to original sources
PubMed1982

Ionic and non-ionic contrast media interaction with anticoagulant drugs.

Normal and pathologic human plasmas were incubated with radiographic contrast media, heparin, Dextran-40 and saline. Renografin-60 produced a strong anticoagulant effect and the clotting times were significantly prolonged; the addition of heparin resulted in greatly elevated thrombin time. No such prolongation was noted with Dextran-40. P-297, ioxaglic and ioxithalamic acids also showed similar anticoagulant properties. When dogs were injected with contrast media and heparin, the overall anticoagulant effect lasted for more than 6 hours, while contrast media or heparin effect remained for a short period of time. Clinical significance of contrast media interactions with anticoagulant drugs is discussed.

Animals↗
PubMed1982

Contrast media induced serotonin release in human blood.

Several contrast media were tested for their ability to release serotonin from whole blood. Renografin-60, Hypaque M-75, Vascoray and Conray were incubated with human blood at 37 degrees C for 60 min. Platelet-poor plasma was analysed for serotonin using a high performance liquid chromatographic technique. Seven non-ionic contrast media were similarly incubated and serotonin levels determined. Ionic contrast media induced a greater release of serotonin compared with non-ionic ones. The amount of serotonin was not proportional to iodine concentration in blood. These results suggest that hypertonic solutions of contrast media produce a physical injury to platelets causing them to release their granular contents.

Adult↗
PubMedDate not supplied

Effects of nonionic contrast media (CM) on the components of coagulation and complement systems.

Several nonionic experimental contrast media (CM) were evaluated for their effects on coagulation cascade, platelet aggregation, and the activation of complement pathways. In an in vitro system, most of the contrast media tested showed a mild anticoagulant property by prolonging the clotting times, such as partial thromboplastin time and the thrombin time of pooled normal human plasma. However, aggregation of normal human platelets by adenosine-diphosphate (ADP), collagen, epinephrine, ristocetin, and thrombin was not blocked when the platelet-rich plasma was incubated with these agents. No quantitative or qualitative changes in the complement components C3 or C4 were detected when a mixture of CM and pooled normal human serum was analyzed by radial immunodiffusion, immuno- or crossed-immunoelectrophoresis techniques. These results indicate that nonionic contrast media produce certain transient hematologic changes and should be further tested for their immunologic properties in order to establish their absolute safety in diagnostic procedures.

Blood Coagulation↗
PubMedDate not supplied

Antiplatelet action of intravascular contrast media. Implications in diagnostic procedures.

The antiplatelet action of intravascular contrast media (CM) Renografin-76 (diatrizoate meglumine and diatrizoate sodium) was studied in vitro and in 21 patients undergoing radiodiagnostic procedures. In vitro studies suggested that in Renografin-76, meglumine was the chief constituent responsible for its antiplatelet action. In post-CM plasma from patients, clotting times were prolonged and platelet aggregation greatly impaired, albeit normal aggregation restored within 3 hours. Although changes in global clotting times and platelet aggregation were mostly transient, it is possible that CM usage in patients with thrombocytopenia, sickle cell phenomenon, and on anticoagulant-antiplatelet drugs may present a serious risk to their hemostatic integrity.

Adult↗
PubMedDate not supplied

Laser nephelometry: development, clinical application, and future prospects.

Plasma protein alpha 1-antitrypsin (alpha 1-AT) and the serum complement component C3 have been quantitated by a laser nephelometric technique. The correlation coefficient between the laser nephelometric and the RID methods was r = 0.87 for alpha 1-AT, and r = 0.80 for C3 in normal serum. The alpha 1-AT concentration determined by the laser method ranged from 161 to 393 mg/dl in normal plasma, whereas the serum C3 concentration in normal serum was found to be 76.5 +/- 21.9 mg/dl. In pathological plasma, higher-than-normal alpha 1-AT levels were found (mean = 300 +/- 105.2 mg/dl), and these elevated levels are consistent with an acute-phase response. These studies indicate that laser nephelometric methods can be conveniently employed and automated for rapid immuno-quantitation of plasma and serum proteins.

Blood Proteins↗