Biomedical subjects

Tsai-Yueh Luo

Publications and source records attributed to Tsai-Yueh Luo.

5 recordsLinked to original sources

PubMed2006

A design for automatic preparation of highly concentrated 188Re-perrhenate solutions.

Rhenium-188 is extremely suitable for the radiotherapy of balloon dilation for the coronary artery restenosis. To satisfy the need of highly concentrated (188)Re-perrhenate for the clinical applications, we designed an apparatus to achieve the purpose of concentrating (188)Re-perrhenate solution. This apparatus comprised of a concentrator, a control box and a computer with an automatic control program. A column of cation-exchange resin in Ag(+) form and an anion-exchange column in series were used in the concentration procedure. More than 90% of (188)Re isotope in the original solution could be collected with 1mL of 0.9% NaCl solution added to collect the (188)Re adsorbed in the column in this final process (90.7+/-2.2%, n=15). We also found that the radiochemical purity in the final solution remained unchanged (100%). The designed process could automatically increase the quality and efficiency of the production of highly concentrated rhenium-188 solution, and could also reduce the radiation dose absorbed by the operator.

Chromatography, Ion Exchange↗

PubMed2006

A comparison of biodistribution between 111In-DTPA octreotide and 111In-DOTATOC in rats bearing pancreatic tumors.

111In-DTPA octreotide (DTPAOC) has been used for detecting somatostatin receptor positive tumor for years. In-111 DOTA-Tyr3-octreotide (DOTATOC) is newly developed for diagnostic and therapeutic purposes. In this study, we compared the biodistribution and tumor uptake ratio after injection of In-111 DTPAOC and In-111 DOTATOC in rats. Twelve rats bearing pancreatic tumors were divided into two groups: six rats were sacrificed at 4 hr after injection of 3.7 MBq of In-111 DTPAOC and another 6 rats were sacrificed at the same time after injection of 3.7 MBq of In-111 DOTATOC. Samples of various organs were obtained and counted to calculate the tissue concentration. In addition, 12 rats bearing pancreatic tumors were scanned at 4, 24, and 48 hr after injection of 37 MBq of In-111 DTPAOC or In-111 DOTATOC. The tumor uptake ratios (T/N ratio) were calculated. The biodistribution data showed that the activity in the tumor as well as in the kidney was significantly higher in the In-111 DOTATOC group than in the In-111 DTPAOC group, although both radiopharmaceuticals had the expected high affinity to the tumor. The T/N ratios in the In-111 DOTATOC group were also significantly higher than those in the In-111 DTPAOC group at 24 hr after injection. We conclude that In-111 DOTATOC showed lower clearance than In-111 DTPAOC in the rats bearing pancreatic tumors, although both of these radiopharmaceuticals showed expected high tumor uptake.

Animals↗

PubMed2004

Preparation and biodistribution of rhenium-188 ECD/Lipiodol in rats following hepatic arterial injection.

Radiolabeled Lipiodol has routinely been used in hepatoma therapy. In this article an attempt to develop a new (188)Re-ECD/Lipiodol radiopharmaceutical, in which the chelating agent ECD (ethyl cyteinate dimer), is the constituent of the known brain perfusion agent (99m)Tc-ECD, and an evaluation of its stability and biodistribution in rats with hepatic tumors is presented. First, (188)Re-ECD was prepared in a vial, followed by extraction with Lipiodol to get the final product, (188)Re-ECD/Lipiodol. The optimal labeling conditions for (188)Re-ECD were: (1) tartaric acid which is better than EDTA as a weak chelating agent; and (2) 15 mg of SnCl(2), as the reducing agent, and 5-10 mg of tartaric acid in each vial had a better labeling yield. The radiochemical purity of (188)Re-ECD/Lipiodol was more than 94%. Twenty-four male Sprague-Dawley rats with liver tumors were sacrificed at 1, 24, and 48 h (eight rats each time) after an injection of approximately 7.4 MBq of (188)Re-ECD/Lipiodol via the hepatic artery. The radioactivity in the liver tumor is significantly high following therapeutic arterial injection, and relatively low in other organs including the bone, spleen, brain, thyroid, stomach, muscle, blood, and testis throughout this study. In conclusion, the new preparation of (188)Re-ECD/Lipiodol is a candidate agent for the treatment of liver cancer.

Animals↗

PubMedDate not supplied

Effect of hypercholesterolemia on myocardial function in New Zealand white rabbits.

Although hypercholesterolemia is a well-known risk factor for atherosclerosis, little is known about the effect of hypercholesterolemia on cardiac contractile function. The objective of this study was to examine the effect of hypercholesterolemia on myocardial contractility. Fifteen New Zealand white rabbits were fed standard chow (control group) and another 15 were fed a cholesterol-enriched diet (HC group) for 12 weeks. The contractile response of ventricular muscle strips was measured in various extracellular calcium concentrations and at different pacing rates. The whole-cell calcium current recording, and mRNA and protein levels of cellular calcium-handling proteins were also analyzed. With 2 mM Ca2+ and stimulation at 3 Hz, the contractile force of HC strips was less than that of the controls (3.63 +/- 0.20 vs. 4.61 +/- 0.50 mN, p < 0.05). The time to peak tension was longer for HC strips (93.3 +/- 2.16 vs. 82.2 +/- 2.81 ms, p < 0.05). The peak L-type calcium inward current density was slightly higher in HC myocytes but did not reach statistical significance (-14.90 +/- 0.94 vs. -12.44 +/- 0.84 pA/pF, p = 0.15). The mRNA level of sarcoplasmic reticulum Ca2+-ATPase (SERCA), normalized to GAPDH, was significantly lower in the HC than that in the control group (2.85 +/- 0.14 vs. 7.67 +/- 0.67, p < 0.05), as was the ryanodine receptor (RyR; 0.42 +/- 0.06 vs. 0.71 +/- 0.13, p < 0.05). The mRNA of the Na+/Ca2+ exchanger (NCX) was statistically higher in the HC group (0.90 +/- 0.12 vs. 0.48 +/- 0.05, p < 0.05). Western blot experiments revealed that protein expression of SERCA in the HC strips decreased, but that of the NCX increased. The protein expression of the dihydropyridine receptor was similar between these two groups. We concluded that hypercholesterolemia results in suppression of the maximal contractile function and in a longer systolic contractile time course. These changes may partially be mediated through a decrease in SERCA and RyR but an increase in NCX expression.

Animals↗

PubMedDate not supplied

Dietary cholesterol affects sympathetic nerve function in rabbit hearts.

In order to assess the effect of hypercholesterolemia on cardiac sympathetic nerve function, New Zealand white rabbits were fed a normal diet (the control group) or one enriched with 0.5% cholesterol [the hypercholesterol (HC) group] for 3 months. Before and after the 3-month diet treatment, we performed serial imaging examinations and analyzed the uptake and washout ratio of (123)I-meta-iodobenzylguanidine ((123)I-MIBG) from the myocardium by administration of (123)I-MIBG through an ear vein. At the end of the experiments, the rabbits were sacrificed, and right ventricular strips were taken from their hearts. The inotropic response of the right ventricular strips to isoproterenol (ISO) and norepinephrine (NE) were evaluated. The cardiac MIBG uptake of the HC group, which was evaluated using the heart to mediastinum ratio, was higher than that of the age-matched control group. However, the washout ratios of (123)I-MIBG did not differ statistically between the two groups. On pretreatment with cocaine, NE-enhanced contractility was greater in papillary muscles isolated from the HC group. The concentration-response curve to ISO was shifted to the right in the HC group, compared with that in the control group. In conclusion, hypercholesterolemia in rabbits resulted in an increase in sympathetic nerve density in the myocardium, a decrease in the inotropic response to ISO and an increase in the inotropic response to NE in cocaine-treated myocardium. Both the in vivo and in vitro studies demonstrated the functional significance of neural remodeling induced by hypercholesterolemia.

3-Iodobenzylguanidine↗