Biomedical subjects

M Blau

Publications and source records attributed to M Blau.

At least 55 records · Page 3Linked to original sources

PubMed1978

Subcutaneous isoproterenol: a convenient rat model for early detection of myocardial necrosis.

The uptake of Tc-99m pyrophosphate was studied in rat myocardial lesions produced by a single subcutaneous injection of isoproterenol (10--50 mg/kg of body weight). The uptake in the whole heart of treated rats is directly proportional to the isoproterenol dose. The Tc-99m PPi uptake measured at various times after lesion initiation parallels the myocardial calcium concentration changes. This model is useful for screening radiopharmaceuticals, and may also be suitable for studying early uptake in myocardial infarcts.

Animals↗

PubMed1978

Uptake of Tc-99m monophosphate complexes in bone and myocardial necrosis in animals.

Bidentate monophosphates--phosphonoacetate (PAA), 2-phosphonoproprionate (PPA), 2-methyl-2-phosphonoproprionate (MPPA), and carbamyl phosphate (CAP)--which are pyrophosphate analogs, were successfully labeled with Sn(II)-reduced [99mTc] pertechnetate in high yield (greater than 95%). Biodistribution studies show that these Tc-99m-labeled monophosphates do localize in bone. At 2 hr after injection, Tc-99m CAP has average femur uptakes of 1.9% in rats and 2.9% in rabbits, which correspond to calculated total-bone uptakes of 38% and 58%, respectively. These are comparable with the femur uptakes for Tc-99m methylene diphosphonate (MDP), which are 1.8% in rats and 2.7% in rabbits. However, the blood clearance rate for Tc-99m CAP was slower than that observed for Tc-99m MDP making the former less desirable for use as a bone-scanning agent. The femur uptakes for Tc99m PAA are 0.9% in rats and 1.2% in rabbits, corresponding to 18% and 24% in total bone, respectively. The PAA derivatives PPA and MPPA have much lower bone uptake. Technetium-99m CAP also concentrates in necrotic myocardium in rats, in amounts comparable to Tc-99m pyrophosphate.

Animals↗

PubMed1977

The effect of window fraction on the deadtime of Anger cameras: concise communication.

The deadtime characteristics of an Anger camera are analyzed using a model consisting of a paralyzable front end and nonparalyzable display circuits. This model differs from previous deadtime analyses in that it considers the change in the fraction of counts passed by the pulse height analyzer as a function of the true count rate. Deadtime curves are analyzed for a Pho/Gamma IV Anger camera using 10%, 20%, and 35% windows.

Mathematics↗

PubMed1977

Effect of oxygen on the reduction of pertechnetate by stannous ion.

The effect of oxygen on the reduction of sodium pertechnetate by stannous chloride has been investigated using a paper electrophoresis method. It has been shown that oxygen interferes with the reduction process by oxidizing stannous ion, Sn(II), to stannic, Sn(IV), thereby leaving less Sn(II) available for the reduction of pertechnetate ion. In a solution of 1.66 X 13(-3)M TcO4- saturated with oxygen, a 3.4 molar ratio of Sn(II) to TcO4- was required for complete reduction of TcO4-, whereas in a nitrogen atmosphere, a 2.4 molar ratio was required for the same purpose. The oxygen interference increases as the concentration of TcO4- decreases. In a nitrogen atmosphere, 1.40 and 10.05 molar ratios of Sn(II) to TcO4- were required for the complete reduction of 1.66 X 10(-2)M and 1.66 X 10(-5)M TcO4- respectively. Once the reduction is accomplished, however, it is not easily reversible. Bubbling with oxygen for 1 hr had no effect on the quantity of reduced technetium.

Oxidation-Reduction↗

PubMed1977

Charge and nature of technetium species produced in the reduction of pertechnetate by stannous ion.

By using a cation-exchange distribution technique, the net charge of the technetium species produced in the reduction of pertechnetate by stannous ion at ph less than or equal to 2 had been determined to be + 2. The species carrying this charge is either the dihydroxy technetate (Tc(OH)2(2)+) ion or the oxotechnetate (TcO2+) ion. These species are hydrolysed to technetium dioxide dihydrate (TcO2 - 2H2O) at higher pH.The advantage of the ion-exchange distribution technique for these studies is that they can be done with carrier-free technetium rather than at the high concentrations required for the more conventional methods of ion-charge determination. The results, therefore, are more likely to be applicable to the situation existing in the routine preparation of Tc-99m radiopharmaceuticals.

Ions↗

PubMed1975