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Biomedical subjects

K Hisada

Publications and source records attributed to K Hisada.

At least 235 records · Page 13Linked to original sources
PubMed1986

Congenitally corrected transposition of the great arteries associated with the pre-excitation syndrome.

A case with congenitally corrected transposition of the great arteries associated with the pre-excitation syndrome is presented. A gated-blood-pool study and Tl-201 myocardial imaging were performed using SPECT. The tomographic gated-blood-pool images showed the shapes of the right ventricle (RV) and left ventricle (LV), i.e., anatomically LV and RV respectively, to be reversed from that of normal patients. The relationships of the great vessels and ventricles also were easily visualized. RV hypertrophy (anatomical LV) was visualized on the Tl-201 images. Phase analysis showed the earliest excitation was in the anteroseptal region near the base of the LV, which was consistent with the site of the accessory conduction pathway. The gated-blood-pool and Tl-201 tomographic studies were helpful for demonstrating the corrected transposition of the great arteries and the pre-excitation syndrome.

Female↗
PubMed1986

Functional mapping of ventricular contraction and phase using single-photon emission computed tomography (SPECT).

A method for functional mapping of ventricular contraction and phase was developed using gated blood-pool SPECT. Parameters of contraction and phase were calculated using length-based and count-based Fourier analyses. In length-based Fourier analysis (LFA), percentage-shortening and length-based phase were calculated based on the changes of lengths from a ventricular centre to edges. In count-based Fourier analysis (CFA), phase and amplitude were also calculated using serial tomographic phase images. Two-dimensional polar display format was employed to summarize the SPECT data of whole cardiac surface. This program was applied to evaluate coronary artery disease and conduction anomalies. The polar functional map using gated blood-pool SPECT can be an effective method to integrate three-dimensional cardiac information in conjunction with myocardial SPECT studies.

Erythrocytes↗
PubMed1986

Thallium-201 radioactive implant induced X-ray emission scanning of stable iodine distribution in thyroid--phantom experiment.

A new method has been developed for imaging the thyroid gland by the use of 201Tl radioactive implant induced X-ray emission (RIXE). The thyroid phantom was made from two cylindrical tubes embedded in plastic neck phantom. Each tube consisted of stable iodine and 201Tl radioactive source in 10 ml water solution. Some photopeaks in the energy range from 20 to 200 ke V were scanned along a horizontal axis by the collimated Ge detector with high energy resolution. The distribution on the horizontal axis was obtained for the generated I K alpha-ray and some primary 201Tl radiations. The 201Tl RIXE scanning can provide information about the distribution of iodine with 201Tl as well as 201Tl distribution in the thyroid gland. The effectiveness of the 201Tl RIXE technique as a thyroid scanning method is discussed.

Iodine↗
PubMed1986

[High-yield synthesis of 14C labeled alicyclic amino acids with high specific radioactivity using potassium (14C) cyanide].

In order to study the tumor specificity of synthetic nonmetabolizing amino acids, 10 different 14C labeled alicyclic amino acids (3a-3j) were synthesized in high yield and with high specific radioactivity. Carbon-14 labeled alicyclic hydantoins (2a-2j) were synthesized from a small amount of radioactive potassium [14C] cyanide and corresponding ketones (1a-1j). Th 14C hydantoins (2a-2j) thus obtained were hydrolyzed without isolation to give 14C labeled alicyclic amino acids (3a-3j). The overall radiochemical yields of the amino acids (3a-3j) from potassium [14C] cyanide were 55.6-93.2% with radiochemical purity more than 99%. Specific activities of these 14C labeled compounds (3a-3j) were 209- 250 MBq/mmol (5.66-6.75 mCi/mmol). When non-radioactive potassium cyanide was not added as a carrier, 1-aminocyclopentane[14C]-carboxylic acid (3b) and 1-aminocyclooctane[14C]carboxylic acid (3e) were synthesized in the yield of 64.9 and 19.0% respectively with the specific activity exceed more than 1.85 GBq/mmol (50mCi/mmol).

Amino Acids↗
PubMed1986

[Washout rate in hypertrophic cardiomyopathy assessed by exercise myocardial scintigraphy].

The present study clarified the pathogenesis of disproportional hypertrophy in terms of disturbed coronary microcirculation. Twenty-eight patients with hypertrophic cardiomyopathy (HCM) who had normal coronary angiograms were categorized in four groups according to distributions of disproportional hypertrophy on left ventriculography and biventriculography: (1) Interventricular septal hypertrophy, (2) septal and apico-anterior wall hypertrophy, (3) apico-anterior hypertrophy, and (4) nonspecific hypertrophy of the entire wall. All 28 HCM patients and 10 normal volunteers were tested using exercise myocardial scintigraphy, and the circumferential profiles were processed by computer to relate the washout rate and disproportional hypertrophy. Comparison of the mean curves and mean segmental values of the circumferential profiles of the HCM groups with those of the control group showed that the mean initial uptake values of the HCM groups were to be relatively low in the apical segment and in the lower portion of the anteroseptal segment representing disproportional hypertrophy of these segments. The mean values were significantly elevated in the upper portion of the anteroseptal segment which was projected as the largest amount of the myocardium three-dimensionally. The mean washout rates in the HCM groups were significantly decreased in all segments, especially in those segments which reflected disproportional hypertrophy. This trend was also observed in the segments with increased initial uptakes. On comparing the segmental values of all groups, the segments with initial uptakes and/or washout rates with having the mean value minus 2SD of the control group were observed in the profiles of 12 of the 28 HCM patients. These all had decreased washout rates. In 25 of the total segments of the HCM patients, the initial uptakes and/or washout rates were below the normal limit; 21 of these segments had only decreased washout rates, and 16 of these 21 segments belonged to disproportionally hypertrophic wall. These results indicate that the decreased washout rate in the disproportionally hypertrophic wall is characteristic of HCM. It is suggested that the decreased washout rate with the decreased initial uptake is caused by disturbance of the coronary microcirculation. In addition, the decreased washout rate without a decreased initial uptake is caused not only by disturbance of coronary microcirculation, but by a metabolic disturbance of the myocardial cells as well. Furthermore, both disturbances are closely related to the pathogenesis of disproportional hypertrophy.

Adult↗
PubMed1986

Length-based Fourier analysis in the pre-excitation syndrome.

Length-based Fourier analysis (LFA) was applied to tomographic gated blood-pool study, and phase and percent-shortening diagrams were generated. In 22 patients with pre-excitation syndrome and ten control subjects, the most basal short-axis section was used for tomographic analysis. When the initial abnormal phase was considered as the location of accessory conduction pathway (ACP), correct diagnosis for the localization of ACP was given in 19 of 22 patients. In ten control subjects, no specific segments of initial phase were noted, although six patients had initial phase in the septal or paraseptal segments. The tomographic LFA was more effective for pinpointing the segment of the earliest phase than tomographic count-based phase analysis. The LFA provided objective three-dimensional information for contraction sequence. Because movements of ventricular edges are essential in tomography, the LFA was considered to be a reasonable approach for the analysis of tomographic gated blood-pool study.

Erythrocytes↗
PubMed1986

Multicompartmental analysis of the kinetics of radioiodinated monoclonal antibody in patients with cancer.

A conceptual biologic model was developed and used to analyze the behavior of 123I-Lym-1 monoclonal antibody against African human B cell lymphoma in patients with B cell lymphoma. Originally, the observed data could not be simulated with parameters for homologous immunoglobulins reported in the literature because of a major processor that was capable of distinguishing this murine immunoglobulin from the patient's own immunoglobulins. With a nonlinear parametric model, the data observed in patients could be fitted to the model. The nonlinear parameter determined the transfer of antibody from the intravascular to a processor compartment, primarily the liver. This transfer was a function of the number of free receptors in the processor. Model simulated curves for the time course of concentration of antibody in the blood for different amounts of injected antibody revealed that blood clearance of radiolabeled antibody was profoundly decreased by increased amount of injected antibody. This model provides an explanation for the observations that tumor imaging is improved with injection of larger amounts of antibody, and a basis for modifying the pharmacokinetic behavior of an antibody in order to optimize radioimmunodiagnosis and radioimmunotherapy.

Antibodies, Monoclonal↗
PubMed1986

Quantitative cerebral blood flow measurements using N-isopropyl-(iodine 123) p-iodoamphetamine and single photon emission computed tomography with rotating gamma camera.

Sixty regional cerebral blood flow measurements were performed on 4 normal volunteers, 7 epileptics, and 40 cerebrovascular disorders using intravenously injected N-isopropyl-(I-123)p-iodoamphetamine (123I-IMP) and single photon emission computed tomography with rotating gamma camera. Arterial blood sampling was combined for obtaining absolute blood flow values. The brain activity distributions of the tomographic image from 30 min after injection, when brain activity reached a plateau, were corrected to represent 5-min reference values with the use of the monitored entire brain's time-activity curve. Brain mean blood flow values ranged from 54 to 63, 34 to 59, and 20 to 60 ml/100 g/min, in normal volunteers, epileptics, and subjects with cerebrovascular disorders, respectively. Brain mean 123I-IMP uptake corrected for injection dose did not correlate with these absolute flow values. This quantitative method is especially useful for diagnosing diffuse flow reductions, which were observed in 8 (14%) of 56 studies in the patients.

Adolescent↗
PubMed1986

Retention and subcellular distribution of 67Ga in normal organs.

Using normal rats, retention values and subcellular distribution of 67Ga in each organ were investigated. At 10 min after administration of 67Ga-citrate the retention value of 67Ga in blood was 6.77% dose/g, and this value decreased with time. The values for skeletal muscle, lung, pancreas, adrenal, heart muscle, brain, small intestine, large intestine and spinal cord were the highest at 10 min after administration, and they decreased with time. Conversely, this value in bone increased until 10 days after injection. But in the liver, kidney, and stomach, these values increased with time after administration and were highest 24 h or 48 h after injection. After that, they decreased with time. The value in spleen reached a plateau 48 h after administration, and hardly varied for 10 days. From the results of subcellular fractionation, it was deduced that lysosome plays quite an important role in the concentration of 67Ga in small intestine, stomach, lung, kidney and pancreas; a lesser role in its concentration in heart muscle, and hardly any role in the 67Ga accumulation in skeletal muscle. In spleen, the contents in nuclear, mitochondrial, microsomal, and supernatant fractions all contributed to the accumulation of 67Ga.

Animals↗