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Biomedical subjects

Y Yano

Publications and source records attributed to Y Yano.

At least 307 records · Page 17Linked to original sources
PubMed1988

Survival of rabbit platelets labeled with gallium 67.

The viability of rabbit platelets labeled with radioactive gallium was determined to analyze the feasibility of using platelets labeled with gallium 68 as an imaging reagent for positron emission tomography. Platelets were labeled with a complex of the longer lived gallium 67 and mercaptopyridine-N-oxide (MPO) or with sodium chromate Cr 51. Their survival after transfusion was measured. Labelling efficiency of 67Ga-MPO was 6.5% to 45.8% (26.8% +/- 2.8%) when platelets were suspended in saline solution, but was much lower (1.6% +/- 0.8%) in plasma. Platelets labeled with either radioisotope in a saline medium survived as well as platelets labeled with 51Cr in plasma. Recovery values 1 hour after transfusion and mean platelet survivals were 68.6% +/- 4.9% and 3.4 +/- 0.2 days for 67Ga in saline solution, 76.5% +/- 6.8% and 3.8 +/- 0.5 days for 51Cr in saline solution, and 73.7% +/- 7.4% and 3.6 +/- 0.5 days for 51Cr in plasma. Labeled platelet concentrates always contained extra radioactivity not firmly bound to viable platelets. A postlabeling wash in saline solution did not reduce this contamination and resulted in reduction of the number of viable platelets. The results showed that rabbit platelets labeled with 67Ga-MPO survived in the circulation as well as those labeled by a standard protocol with sodium chromate Cr 51.

Animals↗
PubMed1987

Effects of temperature on development and growth in the tick, Haemaphysalis longicornis.

As a part of ecological studies on Haemaphysalis longicornis, the effects of controlled temperatures (12, 15, 20, 25 and 30 degrees C; approximately 100% RH) on development and growth of the tick were investigated and the critical low temperature for each stage in the life cycle was estimated. As the temperature became low, the periods of preoviposition, oviposition, egg hatching (incubation) and moulting were prolonged. At 12 degrees C, however, oviposition, egg hatching and moulting of the larva and nymph did not occur. The critical low temperatures for oviposition, egg hatching (developmental zero) and larval and nymphal moulting, which were calculated theoretically from the regression equations, were 11.1, 12.2, 10.2 and 11.8 degrees C, respectively. The temperature also affected the egg productivity and hatch-ratio. The number of deposited eggs per mg of body weight decreased markedly at 15 degrees C, and the hatch-ratio was lowered with dropped temperatures.

Animals↗
PubMed1987

Calcium-accentuated ischemic damage during reperfusion: the time course of the reperfusion injury in the isolated working rat heart model.

The purpose of this study was to determine the time course of calcium-induced postischemic reperfusion injury to the myocardium, using an initial short-term calcium-enriched reperfusion solution. The isolated rat heart model was subjected to 30 min of normothermic potassium cardioplegia-induced ischemic arrest. Control hearts received normal calcium Krebs-Henseliet buffer (KHB) reperfusion. Experimental hearts were challenged with 10 min of calcium-enriched (KHB) reperfusion starting at 0, 1, 2, 5, 15, and 30 min after the beginning of reperfusion. Aortic flow recovery 60 min after reperfusion was used to determine functional recovery. Control hearts recovered 82 +/- 3% of preischemic aortic flow. Hearts which received calcium challenge at 0 and 1 min after the start of reperfusion recovered 43 +/- 4 and 69 +/- 3% of preischemic aortic flow, respectively (P less than 0.01 and P less than 0.05, respectively). Hearts which received calcium challenge 2, 5, 15, and 30 min after reperfusion recovered 75 +/- 2, 80 +/- 2, 85 +/- 2, and 83 +/- 2% of preischemic aortic flow, respectively. Our results indicate that the postischemic myocardium is very susceptible to calcium-accentuated ischemic damage during the initial period of reperfusion. The postischemic heart, however, quickly recovers its ability to withstand a calcium challenge. Five minutes after the start of reperfusion the heart is not influenced by calcium challenge.

Animals↗
PubMed1987

Comparative evaluation of electrophilic aromatic iododemetallation techniques for labeling radiopharmaceuticals with iodine-122.

A series of metallated arenes bearing sigma-bonded tin, mercury, germanium, boron, or silicon were evaluated as labeling substrates for the generator-produced positron emitter 122I(t1/2 = 3.6 min). Using dichloramine-T with 122I, radiochemical yields exceeding 90% were achieved after 1 min at 25 degrees C using stannylated or mercurated arenes in ethanol, or germylated arenes in acidic solvent. Stannylated or mercurated arenes resulted in high labeling yields even with deactivated aromatics in ethanol, but regiospecifically-iodinated products were obtained only from stannylated precursors due to differences in the syntheses of these organometallics. The implications of these results to the labeling of radiopharmaceuticals with 122I are discussed.

Benzene Derivatives↗
PubMed1987

Essentials of a rubidium-82 generator for nuclear medicine.

The use of generator-produced 82Rb for positron emission tomography studies in clinical nuclear medicine requires a number of factors to be considered. These include 82Sr availability, methods of recharging the generator with fresh 82Sr, adequate elution yield of 82Rb, low breakthrough of 82-85Sr, simple and reliable operation of the generator, and delivery of a sterile and pyrogen free eluate of 82Rb.

Electrons↗
PubMed1987

Protection of the pediatric myocardium. Differential susceptibility to ischemic injury of the neonatal rat heart.

Myocardial protection during pediatric cardiac operations has been suggested to be less successful than in adult hearts. In the present study we have compared the resistance of adult, infant, and neonatal rat hearts to various periods of ischemic arrest with normothermic (37 degrees C) crystalloid cardioplegia. Isolated hearts with intraventricular balloons, from adult (50 to 60 days of age, heart weight 865 +/- 13 mg), infant (20 to 25 days of age, heart weight 251 +/- 3 mg), and neonatal rats (3 to 5 days of age, heart weight 40 +/- 1 mg) were subjected to 10, 20, 30, 40, 50, 60, 80, and 100 minutes of ischemia (n = 6 hearts for each time point and for each age group). St. Thomas' Hospital cardioplegic solution was infused at the onset of the period of arrest. With increasing durations of ischemia there was a declining postischemic recovery of function. Up to 40 minutes of ischemia there was no significant difference between the three age groups in postischemic recovery of left ventricular developed pressure: 40.3% +/- 4.4%, 45.4% +/- 6.5%, and 44.4% +/- 2.2% of preischemic control for adult, infant, and neonatal hearts, respectively. Beyond 40 minutes adult and infant hearts showed an identical deterioration with effectively no recovery beyond 60 minutes of ischemia. By contrast, neonatal hearts were much more resistant to ischemia. After 100 minutes of ischemia the mean recovery of left ventricular developed pressure was 20.9% +/- 1.1%, whereas in infant and adult hearts the values were 0.6% +/- 0.3% after 80 minutes of ischemia and 0% after 100 minutes, respectively. Analysis of creatine kinase leakage also indicated that with ischemic durations in excess of 40 minutes, the neonatal heart was far more resistant to ischemia, and creatine kinase leakage per gram dry weight was much less than in infant or adult rats. Analysis of the rates of recovery during reperfusion again revealed differences between neonatal hearts and hearts from the other two age groups. We conclude that in the normal rat the neonatal heart has a greater inherent tolerance to ischemia than that of the infant or adult rat.

Animals↗
PubMed1986

A 122Xe-122I generator for remote radio-iodinations.

A 122Xe-122I generator system is described that produces 122I extraction efficiencies of approximately 60%. Radiocontaminants were less than 0.1% at the time of 122I removal following a 10 min ingrowth period. The chemical form of 122I was identified as [122I]iodide, and the [122I]iodide was remotely incorporated into radiopharmaceuticals for PET studies with an overall efficiency of as much as 40%.

Iodine Radioisotopes↗
PubMed1986

18F-labelled N,N-dimethylamphetamine analogues for brain imaging studies.

The radiochemical yields of nine N,N-dimethyl-2-(substituted phenyl)-isopropylamines (amphetamine analogues) were determined following reaction with [18F]acetyl hypofluorite in a 0.1 M HCl solution at room temperature. The meta-dimethoxy substituted amphetamines gave the highest radiofluorination yields (24-32% at EOB). Purification of the 18F-labelled amphetamines was achieved in 10-20 min. 5-18F-2,4-Dimethoxy-N,N-dimethylamphetamine (5-18F-2,4-DNNA) was utilized to determine brain and lung uptake in rates. Positron emission tomography studies were conducted in a dog to determine the dynamic brain uptake and retention of this agent. The 5-18F-2,4-DNNA exhibited decreased initial uptake and more rapid loss of radioactivity in cerebral tissue compared to the iodinated homologue.

Animals↗