Biomedical subjects

K Hayashida

Publications and source records attributed to K Hayashida.

At least 181 records · Page 10Linked to original sources

PubMed1992

[Diagnostic utility of myocardial imaging using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid in ischemic heart disease].

We evaluated the myocardial metabolism in the acute and subacute phases of myocardial infarction or unstable angina using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid (BMIPP). We then compared those findings with (1) myocardial perfusion images obtained with 201TlCl and (2) the regional and global left ventricular function determined by left ventriculography. Thirty-one patients were examined, consisting of 16 with acute myocardial infarction (6.8 +/- 2.6 days after onset), 8 with subacute myocardial infarction (35 +/- 3.0 days after onset) and 7 with unstable angina. The BMIPP images showed a larger uptake-defect than 201TlCl images in the patients in the acute or subacute phase of myocardial infarction. This finding was especially remarkable in the acute phase after successful coronary revascularization therapy. Moreover, in such cases, the myocardial BMIPP uptake improved to the same degree as 201TlCl one month later. The decrease in myocardial uptake of BMIPP agreed well with the decrease in regional wall motion in the acute and subacute phases of myocardial infarction. In contrast, the myocardial perfusion of 201TlCl did not always agree with the regional wall motion in stunned or hibernating myocardium, where BMIPP showed an uptake-defect in the acute phase but improved in the subacute phase. Thus, BMIPP is surmised to be able to depict fatty acid metabolism in in vivo myocardial imaging.

Adult↗

PubMed1992

[Usefulness of 201Tl myocardial scintigraphy after dipyridamole infusion in patients with atherosclerotic vascular disease].

To determine the utility for detecting ischemic heart disease (IHD), Dipyridamole thallium myocardial images (DIP-Tl) have been performed in the 103 patients with atherosclerotic vascular disease who can't exercise fully. Of 103 patients, there were 36 patients with arteriosclerosis obliterans (ASO), 31 patients with aneurysm of the abdominal aorta (AAA), 24 patients with aneurysm of the thoracic aorta (TAA) and 12 patients with dissecting aortic aneurysm (DAA). Clinical evidence of IHD was found in 20 patients with ASO, 10 with AAA, 7 with TAA and 4 with DAA respectively. Positive evidence of DIP-Tl was identified in 66% of 41 patients who had clinical evidence of IHD, and particularly in the patients with AAA (80%) and ASO (65%). On the other hand, in the patients without clinical evidence of IHD, positive evidence of DIP-Tl was identified in 19% of 62 patients and particularly in the patients with AAA (39%). In all patients, the percentage of the positive DIP-Tl ratio was 38%. And, when the 38% patients of the positive DIP-Tl were added to the patients of the negative DIP-Tl who had clinical evidence of IHD, almost half patients (51%) were considered to be complicated with IHD. This study suggests that the atherosclerotic vascular disease is highly complicated with IHD and DIP-Tl is useful to detect IHD.

Aged↗

PubMed1992

Diagnostic value of technetium-99m radionuclide angiography for detecting thrombosis in left atrial appendage.

In mitral valve disease, it is important to know whether thrombi are present in the left atrium when deciding upon a course of treatment. The left atrial thrombus usually locates in the left atrial appendage. In most cases of mitral valve disease, the left atrial appendage is clearly demonstrated by radionuclide angiography using 99mTc-labeled red blood cells and it can be speculated that the cases in which left atrial appendage are not demonstrated by RNA have left atrial thrombi. On the basis of this hypothesis, the diagnostic accuracy of radionuclide angiography to detect left atrial thrombi was evaluated retrospectively in 60 patients with mitral valve disease who had undergone surgery. The sensitivity of first-pass and equilibrium radionuclide angiography to detect left atrial thrombi was 83% and 67%, the specificity 79% and 54%, and the accuracy 80% and 57%, respectively. Although there were two false-negative cases in which the left atrial thrombi did not locate in the appendage and 10 false-positive cases in which left atrial appendages were not dilated, the negative predictive value was so high that a clearly demonstrated left atrial appendage can be translated into the absence of left atrial thrombi.

Adult↗

PubMed1991

Reconstitution of functional receptors for human granulocyte/macrophage colony-stimulating factor (GM-CSF): evidence that the protein encoded by the AIC2B cDNA is a subunit of the murine GM-CSF receptor.

The high-affinity receptor for human granulocyte/macrophage colony-stimulating factor (hGM-CSF) is composed of two subunits, alpha and beta. The alpha subunit binds GM-CSF with low affinity, whereas the beta subunit does not bind GM-CSF by itself. The alpha and beta subunits together form the high-affinity GM-CSF receptor. The beta subunit has extensive sequence homology with the mouse interleukin 3 (IL-3) receptor (AIC2A) and its homologue (AIC2B) that does not bind IL-3 or other cytokines including GM-CSF. To examine the function of these receptor components, we expressed the alpha subunit of the hGM-CSF receptor with the human beta subunit or the mouse AIC2A or AIC2B in a mouse IL-3-dependent pro-B-cell line, Ba/F3, and in a mouse IL-2-dependent T-cell line, CTLL2. Coexpression of the alpha and beta subunits in Ba/F3 and CTLL2 cells resulted in high-affinity hGM-CSF binding and growth response to low concentrations of hGM-CSF. Whereas Ba/F3 cells expressing the alpha subunit alone proliferated in response to high concentrations of hGM-CSF, CTLL2 cells expressing the alpha subunit alone did not respond to hGM-CSF at all. Since Ba/F3 cells express endogenous AIC2A and AIC2B whereas CTLL2 expresses neither of them, we examined the possibility that either AIC2A or AIC2B is involved in the formation of a functional GM-CSF receptor. The expression of the human alpha subunit with AIC2B, but not with AIC2A, in CTLL2 cells conferred a growth response to hGM-CSF. These results indicate that the beta subunit of the GM-CSF receptor is required for generation of growth signals and that AIC2B is likely the beta subunit of the mouse GM-CSF receptor.

Animals↗

PubMed1991

Change of accumulation and filling pattern in evolution of cerebral infarction with I-123 IMP brain SPECT.

Twenty-eight patients with cerebral infarction were examined by brain SPECT with I-123 IMP a total of 46 times from Day 2 to Day 84 after the onset of stroke. Depending on the pattern of change in the abnormal accumulation of I-123 IMP between the early and delayed images, the patients were classified into one of five types. The number of patients in each type and the number of days after infarction at which each type occurred were as follows: Type (I), n = 5 and 4 +/- 2 days; Type (II), n = 8 and 12 +/- 4 days; Type (III), n = 17 and 21 +/- 11 days; Type (IV), n = 13 and 38 +/- 18 days; and Type (V), n = 3 and 60 +/- 16 days. In 12 patients, 30 brain SPECT were performed that showed the chronological evolution of infarction in sequence from Types (I) to (IV). Hyperactivity in the early image was seen in Type (I) with a subsequent image defect, while in Type (II) there was persistent hyperactivity. Hypoactivity in the early image was seen in Types (III), (IV), and (V), and the activity in the delayed image gradually decreased as the process of infarction terminated. The early image reflected the distribution of lipophilic I-123 IMP, indicating regional cerebral blood flow, while the delayed image showed the distribution of hydrophilic I-123 IMP metabolites superimposed on that of lipophilic I-123 IMP which had accumulated in the brain at the first extraction. Combining the early and delayed images of I-123 IMP brain SPECT may help to understand the evolution of cerebral infarction.

Adult↗

PubMed1991

Identification of the rate-dependent functional refractory period of the atrioventricular node in simulated atrial fibrillation.

We continuously observed successive pairs of R-R intervals during atrial fibrillation and hypothesized that the shortest R-R interval for a given preceding R-R interval in a pair represents the functional refractory period of the atrioventricular node at that preceding interval. To test this hypothesis we simulated atrial fibrillation in 28 isolated cross-perfused canine hearts and obtained an R-R interval scatterplot by plotting the R-R intervals as a function of the immediately preceding R-R interval. This scatterplot enabled us to detect a series of the shortest R-R intervals for a wide range of preceding R-R intervals, and this allowed us to estimate the rate-dependent functional refractory period of the atrioventricular node in simulated atrial fibrillation. The estimated functional refractory periods correlated well with those measured by the conventional method (r = 0.93). We conclude that the proposed method makes it possible to estimate the rate-dependent functional refractory periods of the atrioventricular node in atrial fibrillation.

Animals↗

PubMed1991

V(D)J recombinase activity in primary and secondary murine lymphoid organs: assessment by a PCR assay with extrachromosomal plasmids.

We developed a highly specific and sensitive polymerase chain reaction (PCR) assay to measure V(D)J recombinase activity using extrachromosomal plasmids and PCR. Extrachromosomal plasmids were prepared by eukaryotic replication origin, and a combination of the DQ52 and JH2 regions of the murine IgH gene, or of the D beta 2-1 and J beta 2.6 regions of the murine TCR beta gene, both with recombination signal sequences. Plasmids, transfected into cells to be examined and recovered after 48 h, were processed to detect recombined molecules by PCR with primers for the expected sequences produced by the precise signal joint. The PCR assay, when compared with a Camr assay that we prepared with the DQ52 and JH2 regions of the murine IgH gene, seems to have the following advantages. It detects only the recombined products produced by V(D)J recombinase activity and is therefore highly specific. It detects V(D)J recombinase activity in cells, including those with low replication frequency, which our Camr assay failed to do. This also enables detection of the recombinase activity not only in murine cell lines, but also in cells of murine lymphoid organs. The assay detects V(D)J recombinase activity in cell lines of human origin by replacing the eukaryotic replication origin of plasmids. High V(D)J recombinase activity was detected in bone marrow cells followed by thymic cells, and apparently lower activity was detected in cells of the lymph node and spleen of normal mice.

Animals↗

PubMed1991

Embolic stroke following carotid radiation angiopathy demonstrated with I-123 IMP brain SPECT.

Radiation angiopathy was developed by the process of accelerated atherosclerosis at the site of irradiation. The case of a 44-year-old man with right hemiparesis showing a high signal intensity in the left semioval center on MRI and a defect in the left temporo-parietal area with subsequent filling-in with I-123 IMP brain SPECT is reported. Digital subtraction angiography showed typical radiation angiopathy with ulceration in the left common carotid artery. Twenty-four years previously, he underwent curative irradiation of a neck mass that revealed Hodgkin's disease by biopsy. The emboli formed at the site of radiation-induced angiopathy and caused cerebral infarction. The perfusion abnormality in the territory of the embolic artery was detected by I-123 IMP SPECT. Long-term survivors of neck irradiation are at high risk for the development of carotid arterial disease and should be watched carefully.

Adult↗

PubMed1991

Validation to eliminate vascular activity on 99Tcm-HMPAO brain SPECT for regional cerebral blood flow (rCBF) determination.

Since more than 15% of the injected dose of 99Tcm-HMPAO 10 min after injection labels plasma or red blood cells (RBC), the elimination of vascular activity from actual brain activity is mandatory to evaluate accurately regional cerebral blood flow (rCBF) with 99Tcm-HMPAO brain SPECT. The late image (4 h post-injection) will show a reduced vascular activity of approximately 30% compared to the initial image (30 min post-injection), due principally to a plasma fraction reduction of 54%, and an insignificant reduction of activity in the RBC fraction. The circulating RBC count can then be normalized for both the injected dose and total blood volume, because the entrapment mechanism of 99Tcm-HMPAO with RBC is the same as that with brain retention. After elimination of the vascular contribution using the RBC activity the mean counts in the 14 middle cerebral artery areas from seven cases on 99Tcm-HMPAO SPECT showed a good correlation (r = 0.85) with the initial slope index of 133Xe cerebrography. It was concluded that the elimination of the vascular activity on 99Tcm-HMPAO brain SPECT is needed to quantify rCBF accurately.

Adult↗

PubMed1991

[Quantitative evaluation of myocardial viability using Tl-201 myocardial SPECT].

In order to evaluate myocardial viability, we developed a new method for quantification of redistributed area in Tl-201 myocardial SPECT, and it was applied to 71 patients with LAD lesion. Initial image was subtracted from delayed image, and redistributed area was displayed as an unfolded map (viability map). Extent and viability score, which correspond to extent and degree of the viable area, was also calculated. In the cases with prior myocardial infarction, viability score was widely distributed and extent score was smaller, while the cases with angina pectoris had larger extent score. Visual assessment of redistribution to the infarcted area was compared with % score, which was calculated as ratio to initial defect score. When the criteria of viability was defined as % viability score greater than 36 or % extent score greater than 16, quantitative evaluation agreed with visual assessment, and corresponded to clinical course. This method was considered to be effective for evaluation of extent and degree of myocardial viability, but further evaluation need to be done in comparison with reinjection, PET study, and so on, and usefulness in multi-vessel disease.

Adult↗

PubMed1991

[Hemodynamic assessment before and after PTMC by using cardiac blood pool scintigraphy].

Rest and exercise cardiac blood pool scintigraphy with 99mTc-RBC were performed in 12 patients with symptomatic mitral stenosis before percutaneous transvenous mitral commissurotomy (PTMC) and at one week, one month after PTMC. Comparison of hemodynamic parameters before and one month after PTMC showed that LVEDV (97.4 +/- 8.9 vs. 111.4 +/- 12.1 ml; p less than 0.01) and diastolic indices (1/3FF: 23.6 +/- 6.5 vs. 30.9 +/- 4.1%; p less than 0.01) both increased, while there was no significant change in LVEF and RVEF. Comparison of symptom-limited bicycle exercise before and one month after PTMC showed that the duration of exercise time (7.6 +/- 1.6 vs. 8.6 +/- 1.4 min; p less than 0.02) and anaerobic threshold (10.6 +/- 3.0 vs. 15.4 +/- 3.2 ml/min/kg; p less than 0.01) increased. In comparison of hemodynamic response before and one month after PTMC, there were significant increases in cardiac output (CO) at the same workload (15 W: 3.9 +/- 0.7 vs. 4.8 +/- 0.8 l/min; p less than 0.05, 30 W: 3.9 +/- 0.7 vs. 5.2 +/- 1.2 l/min; p less than 0.05) despite similar CO at rest (3.5 +/- 0.8 vs. 3.9 +/- 0.7 l/min; NS). We conclude that cardiac blood pool scintigraphy is useful to evaluate improvement of hemodynamic parameters and exercise capacity after PTMC non-invasively.

Adult↗

PubMed1991

[Cerebral perfusion scintigraphy in patients with cerebrovascular disease by using 99mTc-ECD: comparative study with 123I-IMP SPECT].

99mTc-ECD SPECT was performed in 19 patients with cerebrovascular disease, and location, extent, and severity of the lesions on 99mTc-ECD SPECT were compared with those on 123I-IMP SPECT. The initial brain uptake was 5.5 +/- 0.7% of the injected dose at 10 minutes after injection, 5.3 +/- 1.3% at 90 minutes, and clearance from the brain is slow. The distribution in the brain was changed, especially washout from the thalamus was slower than that from other regions. The count ratio of perfusion defect to normal area (D/N) on 99mTc-ECD SPECT was unchanged over the time, and had no significant differences from that on 123I-IMP SPECT. 99mTc-ECD SPECT was superior in detection of the lesion in the basal ganglia, and showed the images with superior spatial resolution due to physical characteristics of 99mTc. However, mild ischemic lesion and peri-infarct area was not clearly visualized, while 123I-IMP SPECT could demonstrate these lesions with better contrast.

Aged↗

PubMed1991

[Perfusion lung scintigraphy in primary pulmonary hypertension].

Fifteen cases with primary pulmonary hypertension (PPH) were classified into two groups by using the perfusion lung scan pattern. Eight cases had multiple, small, ill-defined defects (mottled pattern), and remaining seven cases had no mottled pattern. These two groups were compared with mean pulmonary arterial pressure (mean PAP), right ventricular ejection fraction (RVEF), blood gas at room air (PaO2), and alveolar-arterial O2 difference (A-aDo2). The cases with mottled pattern showed a significant increase in mean PAP. There were no significant differences in RVEF, PaO2, and A-aDo2, between the groups. The survival rate of the patients with mottled pattern was significantly lower than that without mottled pattern (p less than 0.05). We concluded that perfusion lung scan is very useful for evaluation of the prognosis in primary pulmonary hypertension.

Adolescent↗

PubMed1991

Assessment of myocardial damage in dilated-phase hypertrophic cardiomyopathy by using indium-111-antimyosin Fab myocardial scintigraphy.

For the detection of myocardial cell damage, an 111In-antimyosin Fab study was carried out on seven patients (Group A) in the dilated phase of hypertrophic cardiomyopathy, seven patients (Group B) with dilated cardiomyopathy, and eight control patients (Group C). Imaging was done 48 hr after intravenous injection of 74 MBq of 111In-antimyosin Fab. Myocardial antimyosin uptake was visually graded as 0, +1, +2 or +3. A score of +2 or +3 was considered positive. The heart/lung ratio of antimyosin uptake (antimyosin index) also was determined. Antimyosin uptake was positive in seven (100%), nine (90%) and no (0%) patients in Groups A, B, and C, respectively. The antimyosin index in Groups A and B was 2.46 +/- 0.49 and 2.04 +/- 0.24, respectively, findings were significantly higher than that in Group C (1.51 +/- 0.13) (p less than 0.01). Positive biopsy findings were noted in only two patients in Group A. Thus, antimyosin uptake was increased in dilated phase hypertrophic cardiomyopathy and dilated cardiomyopathy, which suggests ongoing necrotic changes in these patients.

Adult↗

PubMed1990

Does the washout phenomenon of Tc-99m HM-PAO correlate to the "filling-in" phenomenon of I-123 IMP with brain SPECT?

Using SPECT, the time course of brain uptake was compared between N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) and Tc-99m d,l hexamethyl-propyleneamine oxime (Tc-99m HM-PAO). Of 14 patients with cerebrovascular disease showing areas of the "filling-in phenomenon" (i.e. delayed uptake) with I-123 IMP brain SPECT, 7 exhibited persistent defects with Tc-99m HM-PAO (Group I), and 7 showed early washout after the initial uptake (Group II). The filling-in of I-123 IMP did not always correlate to the washout region of Tc-99m HM-PAO. The temporal changes were also confirmed by semiquantitative analysis. While the filling-in of I-123 IMP was affected by many factors, the washout of Tc-99m HM-PAO was attributed to significant reduction of Tc-99m HM-PAO in the plasma. Delayed imaging of the brain with Tc-99m HM-PAO using SPECT may give a more accurate estimate of regional cerebral blood flow in cerebrovascular disease, because it should be lees effected by cerebral blood volume.

Aged↗

PubMed1990

Abnormal 67Ga uptake in a fibrosarcoma of the pericardium with malignant transformation.

A 31-year-old woman presented with general malaise, back pain, and edema of the lower extremities. A chest X-ray film showed an enlarged cardiac shadow and clear lung fields. A pericardial lesion with decreased activity on blood pool imaging and increased uptake on gallium citrate imaging displaced the heart upwards and to the left. The pericardial mass showed an inhomogeneous signal intensity on MRI and was large enough to obstruct the venous return by compressing the heart. At operation, the mass was found to originate from the pericardium and was histologically identified as a malignant fibrosarcoma. Twelve years previously, the patient had undergone an operation for the removal of a pericardial tumor which was histologically identified as a benign hemangioma. In view of the rarity of pericardial tumors, the present tumor is suspected to have undergone a transformation from benign hemangioma to malignant fibrosarcoma.

Adult↗

PubMed1990

Scintigraphic determination of severity in pulmonary parenchymal damage in patients with atrial septal defect.

According to the pattern observed on a lung perfusion scan, patients with atrial septal defect (ASD) were classified into three stages: stage I, normal perfusion (n = 15); stage II, apical prone perfusion (n = 22); and stage III, mottled perfusion (n = 23). These stages were compared with hemodynamic data obtained from cardiac catheterization and with the right ventricular ejection fraction (RVEF). Staging from I to III correlated well with pulmonary arterial pressure, and patients in stage III showed a significant increase in pulmonary arteriolar resistance and a significant decrease in Qp/Qs. There was no significant difference in RVEF between the stages. We concluded that the scintigraphic severity determined by lung perfusion scan could be valid for evaluating the extent of pulmonary parenchymal damage in patients with ASD.

Cardiac Catheterization↗

PubMed1990

Exercise thallium scintigraphy in aortitis syndrome (Takayasu's arteritis).

It is important for patient management to evaluate coronary arterial involvement in aortitis syndrome. Twenty one cases of aortitis syndrome who experienced chest pain were examined using exercise thallium scintigraphy. The patients were divided into four groups according to the angiographic findings. There were: five patients with left main coronary arterial involvement (group A), four with left or right coronary arterial involvement (group B), nine with aortic regurgitation (group C), and three with pulmonary arterial involvement (group D). In group A and B, all patients had positive ECGs and thallium perfusion defects. Group A patients showed extensive anterolateral perfusion defects, which were compatible with left main coronary arterial involvement. Group C and D patients, who had normal coronary arteries, showed no remarkable perfusion defects although five had positive ECG findings. Thus, the sensitivity and specificity of exercise scintigraphy for detection of myocardial ischemia were 9/9 and 12/12, while those of stress ECG were 9/9 and 7/12 (58%), respectively. It is recommended that exercise thallium scintigraphy be used for detecting clinically occult but significant coronary arterial involvement in aortitis syndrome with chest pain.

Adult↗