Biomedical subjects

K Hayashida

Publications and source records attributed to K Hayashida.

At least 145 records · Page 8Linked to original sources

PubMed1994

[Standardization of regional cerebral count corrected by equilibrium blood count with 99mTc-HMPAO brain SPECT].

To standardize the regional cerebral count with 99mTc-HMPAO, equilibrium blood count of which trapping mechanism is the same as the brain was used in seven patients with cerebrovascular disease. We injected 99mTc-HMPAO 740 MBq in 10-15 sec and got sequential arterial sampling in patients who were undertaken with PET. Four hours later 99mTc-HMPAO brain SPECT was taken and a venous sampling was drawn for determining the equilibrium blood count. Correlation between the area of arterial time activity curve and equilibrium venous blood count was 0.93. After 44 regions (36 in cortical area, 8 in deep area) with 99mTc-HMPAO brain SPECT were placed, SPECT counts were corrected by standardization of equilibrium venous blood count. The correlation between rCBF determined from C15O2 PET and corrected SPECT counts was 0.80 and 0.67, cortical area and deep area, respectively. We concluded that 99mTc-HMPAO brain SPECT count can be corrected by equilibrium blood count to standardize the regional cerebral counts.

Aged↗

PubMed1994

[Myocardial washout of 99mTc-hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) at exercise myocardial scintigraphy in patients with ischemic heart disease].

Myocardial washout of the new myocardial perfusion imaging agent, 99mTc-hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) was studied in 23 patients with coronary artery disease. These patients were divided into three groups; 8 patients with effort angina pectoris (AP group), 6 with myocardial infarction who had reversible defect (MI-RD (+) group) and 9 with myocardial infarction who had not reversible defect (MI-RD (-) group). Regional radioactivities were determined with postexercise 1- and 3-hour myocardial planar images. In AP group, 99mTc-MIBI washout rate in ischemic area was smaller than in normal area (3.8 +/- 7.5% vs. 8.3 +/- 5.6%, p < 0.05), however, in the remaining two groups, there were no difference in washout between normal and infarct areas. Defect/normal ratios from postexercise 1 hour to 3 hours were slightly increased in AP and MI-RD (+) groups. Our results indicate that 99mTc-MIBI showed slight and incomplete myocardial redistribution in ischemic areas. These data showed to be considered in the interpretation of 99mTc-MIBI myocardial imaging.

Aged↗

PubMed1994

[A case of left ventricular hemangioma].

Left ventricle hemangioma in a 54-year-old man is reported. He was admitted to our hospital for chest discomfort. Coronary angiograms showed normal coronary arteries and a contrast blush in the left interventricle septum. Transesophageal echocardiogram also demonstrated the small floating tumor in the ventricular septum below the right coronary cusp. With the aid of cardiopulmonary bypass, the tumor was resected completely through transaortic approach. Histological examination revealed capillary hemangioma. The patient had uneventful recovery. To our knowledge, this is the seventh case of a left ventricular hemangioma treated surgically reported in the world literature.

Heart Neoplasms↗

PubMed1994

[Simultaneous assessment of exercise-induced abnormalities in myocardial perfusion and regional wall motion by using 99mTc-tetrofosmin].

To clarify the usefulness of the combined assessment of exercise (EX)-induced abnormalities in myocardial perfusion and regional wall motion for detecting coronary artery disease (CAD), we carried out first-pass radionuclide angiography and myocardial perfusion imaging during EX and at rest by 99mTc-tetrofosmin. Twenty-four patients with angiographically proven CAD, 9 (Gp A) with single and 15 (Gp B) with multivessel disease, were studied. The sensitivity for the detection of CAD was 78% of Gp A, 73% of Gp B in planar image and 78%, 87% in SPECT image, respectively. When left ventricular ejection fraction and regional ejection fraction (rEF) were combined with the result of myocardial perfusion, sensitivity increased up to 89% of Gp A, 100% of Gp B. Diagnostic accuracy of LAD, LCX and RCA was 79%, 88% and 83%, respectively. Regional EF in ischemic areas decreased during EX in both Gps, particularly in Gp B. Regional EF in relatively normal perfusion areas did not significantly change in Gp A, but decreased in Gp B. These results suggest that 99mTc-tetrofosmin contributes to the improvement of sensitivity for CAD by combined assessment of EX-induced wall motion and myocardial perfusion abnormalities.

Aged↗

PubMed1993

[Detectability of diagonal branch disease with other branch lesions by 201TlCl exercised myocardial scintigraphy].

The detectability of coronary diagonal (Dx) branch disease in 24 patients (16 with myocardial infarction, 8 with angina pectoris; mean age of 56) with other branch (left anterior descending branch [LAD], left circumferential branch [LCX], or right coronary artery [RCA]) diseases was reviewed with 201TlCl exercised myocardial planar and SPECT images. In Dx branch disease with LAD #7 lesion (n = 10), Dx perfusion abnormality was detected in planar and SPECT images in 3 (30%) and 8 patients (80%), respectively. In Dx branch disease with LCX lesion (n = 7), Dx perfusion abnormality was detected in planar and SPECT images in 3 (43%) and 4 patients (57%), respectively. In Dx branch disease with RCA lesion (n = 7), Dx perfusion abnormality was detected in only 1 (14%) and 2 patients (29%), respectively. In conclusion, SPECT is a useful modality for detecting Dx branch disease, but it is sometimes hard to detect Dx branch disease with LCX and RCA lesions.

Coronary Disease↗

PubMed1993

An early cytoplasmic change before Lewy body maturation: an ultrastructural study of the substantia nigra from an autopsy case of juvenile parkinsonism.

Neurons containing a central pale area which may possibly represent an early cytoplasmic change before Lewy body maturation were observed in the substantia nigra from a rare autopsy case of juvenile parkinsonism. Ultrastructurally, such neurons exhibited cytoplasmic swelling along with disappearance of the rough endoplasmic reticulum from the central part of the perikaryon. The pale central cytoplasm was replaced by numerous-cored vesicles, mitochondria, ribosome-like granules and a few Lewy body filaments. The relation of this central pale area to the pale body is discussed.

Brain↗

PubMed1993

Delayed recovery of myocardial perfusion after successful coronary angioplasty of infarct-related artery in patients with prior myocardial infarction.

We studied the status of myocardial perfusion before and after coronary angioplasty (PTCA) of infarct-related artery using stress thallium scan in patients with prior myocardial infarction. Twenty-six patients who had anterior myocardial infarction caused by single-vessel disease at the left anterior descending coronary artery were involved. Patients were classified into the following four groups according to the stress-redistribution thallium scintigraphic findings before PTCA: complete redistribution (two cases), incomplete redistribution (12 cases), partial redistribution (seven cases) and no redistribution (five cases). In the group with complete redistribution, the extent of residual ischaemia in the infarct area decreased significantly after PTCA but infarct size only slightly. In the groups with incomplete and partial redistribution, the extent of residual ischaemia and infarct size decreased significantly after PTCA. In contrast, the group with no redistribution showed a slight decrease in the extent of residual ischaemia and a gradual decrease in infarct size beginning 3 months after PTCA. Clinical findings including electrocardiogram indicated that the patients with incomplete redistribution had more viable myocardium and the patients with no redistribution had more scarring. The groups with incomplete and partial redistribution showed characteristics intermediate between complete and no redistribution. The change of infarct area after PTCA was different between the four groups, but both residual ischaemia and infarct size decreased in all groups. Thus, PTCA of the infarct-related coronary artery is useful even in the patients with prior myocardial infarction, even in patients with no redistribution shown by stress thallium scan.

Adult↗

PubMed1993

Sensitivity and specificity of radionuclide ventriculography with dipyridamole infusion in patients with severe coronary artery disease.

Noninvasive first-pass radionuclide ventriculography may permit the assessment of global and regional left ventricular function during dipyridamole infusion. Twenty patients with > or = 75% stenosis of at least one coronary artery were studied to assess the sensitivity of the technique in detecting coronary artery disease. Seven (35%) had regional dysfunction after dipyridamole infusion, and 16 (80%) developed lower than normal response in left ventricular ejection fraction (an increase of less than 5%) after dipyridamole infusion. When both regional dysfunction and subnormal rejection fraction were considered together, the sensitivity was 80%. Eight normal subjects were studied to assess specificity. None developed regional dysfunction, and left ventricular ejection fraction invariably increased after dipyridamole infusion in all normal subjects, with an increase of less than 5% in only one subject; therefore, the specificity was 88%. It is concluded that the assessment of regional dysfunction with dipyridamole infusion itself is not sensitive, whereas the assessment of changes in left ventricular ejection fraction is sensitive and specific in detecting coronary artery disease.

Coronary Disease↗

PubMed1993

Discrepancies between myocardial perfusion and free fatty acid metabolism in patients with hypertrophic cardiomyopathy.

To test the hypothesis that there are discrepancies between 201Tl- and 123I-beta-methylpentadecanoic acid (BMIPP) distribution in the left ventricular myocardium and to assess whether BMIPP is a useful tracer agent for the assessment of left ventricular function in hypertrophic cardiomyopathy (HCM), myocardial single photon emission computed tomography (SPECT) was performed with 201Tl and BMIPP in five normal subjects and 12 patients with asymmetric septal hypertrophy. Tracer uptake in the left ventricular myocardium was scored using a four-point grading system. A homogenous distribution of the tracer with no discrepancy between 201Tl and BMIPP uptake in the left ventricular myocardium was observed in each normal subject. In contrast, BMIPP uptake was reduced compared to 201Tl in 58 segments (40%) of the 144 myocardial segments in patients with HCM. Such discordant BMIPP uptake was observed in 15 segments (42%) of the septal segments, in 19 segments (53%) of the anterior segments, in eight segments (22%) of the lateral segments, and in 16 segments (44%) of the inferior segments. There was no significant correlation between 201Tl perfusion score and left ventricular ejection fraction, whereas there was a significant correlation between BMIPP perfusion score and left ventricular ejection fraction (r = 0.748; P < 0.01). The results indicated that there were discrepancies between 201Tl and BMIPP uptake in a significant proportion of myocardial segments, suggesting the impairment of fatty acid metabolism and that BMIPP is a useful tracer agent for the assessment of left ventricular function in hypertrophic cardiomyopathy.

Cardiomyopathy, Hypertrophic↗

PubMed1993

Reconstituted human granulocyte-macrophage colony-stimulating factor receptor transduces growth-promoting signals in mouse NIH 3T3 cells: comparison with signalling in BA/F3 pro-B cells.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) plays a critical role in growth and differentiation of myeloid cells. We previously reconstituted high-affinity human GM-CSF receptor (hGM-CSFR) in a pro-B cell line, BA/F3, by cotransfecting alpha- and beta-chain cDNA clones and showed that the reconstituted receptor could transduce growth-promoting signals. The high-affinity hGM-CSFR was also reconstituted in mouse NIH 3T3 cells, but its ability to transduce signals in fibroblasts remained undetermined. In the present study, we further characterized signal transduction by the reconstituted hGM-CSFR in both NIH 3T3 cells and BA/F3 cells. We found that the reconstituted hGM-CSFR transduces signals in NIH 3T3 fibroblasts and BA/F3 cells in response to hGM-CSF to activate transcription of the c-fos, c-jun, and c-myc proto-oncogenes. hGM-CSF also induces protein tyrosine phosphorylation and DNA synthesis in both cell types. These results indicated that hGM-CSFR is functional in fibroblasts, that signal transduction via hGM-CSFR in fibroblasts involves tyrosine kinase(s), and that association of hGM-CSFR with a factor(s) specific to hematopoietic cell lineage is not essential to transduce growth-promoting signals.

3T3 Cells↗

PubMed1993

Perfusion lung scintigraphy in primary pulmonary hypertension.

15 cases of primary pulmonary hypertension were classified into two groups by patterns of perfusion lung scintigraphy. Perfusion scintigrams showed multiple, small, ill-defined defects (mottled + ve) pattern in eight cases, and the remaining seven cases had a normal (mottled - ve) pattern. The mean pulmonary arterial pressure in patients with a mottled pattern (54 +/- 10 mmHg) was higher than in those with a normal pattern (42 +/- 9 mmHg, p < 0.05). There were no significant differences between the two groups in right ventricular ejection fraction, partial pressures of oxygen in the arterial blood or alveolo-arterial oxygen difference. All the patients with a mottled pattern died within 2 years following the lung scintigraphy. There was a significant difference in the survival curves between the two groups. Although our statistical analysis must be evaluated with caution because of small numbers of patients it is suggested that perfusion lung scintigraphy is useful in assessing the prognosis in primary pulmonary hypertension.

Adult↗

PubMed1993

Intracellular magnesium deficiency in acute myocardial infarction.

It has been hypothesized that intracellular magnesium deficiency is a pathogenetic factor in acute myocardial infarction. This study examined the time course of changes in the erythrocyte magnesium concentration and the correlation between the erythrocyte magnesium concentration and the severity of acute myocardial infarction in 49 consecutive patients with transmural acute myocardial infarction. The data were compared with results from 20 control patients without ischemic heart disease. The erythrocyte magnesium concentration (mg/dl) decreased significantly during the acute phase of the infarction (4.86 +/- 0.09 on day 1, 4.89 +/- 0.10 on day 2 and 4.86 +/- 0.10 on day 3 versus 5.26 +/- 0.19 for controls, all P < 0.05) and then normalized gradually to 5.25 +/- 0.10 on day 28. The serum magnesium concentration (mg/dl) also decreased significantly during the acute phase of the infarction (1.93 +/- 0.04 on day 1 and 2.11 +/- 0.03 on day 2 versus 2.26 +/- 0.08 for controls, all P < 0.05), before recovering to 2.28 +/- 0.06 on day 28. There were significant correlations between the erythrocyte magnesium concentration on day 1 and maximal values of serum cardiac enzymes (r = -0.30 for creatine kinase, r = -0.34 for glutamic oxaloacetic transaminase and r = -0.57 for lactate dehydrogenase, all P < 0.05). Moreover, the erythrocyte magnesium concentration was significantly lower in patients with (4.32 +/- 0.08 mg/dl, n = 13) than in those without (5.06 +/- 0.09 mg/dl, n = 36, P < 0.0001) serious arrhythmias. These data indicate that intracellular magnesium deficiency is involved in the acute phase of myocardial infarction.

Adult↗

PubMed1993

[Hepatic protein synthesis in regenerating liver after partial hepatectomy].

The process of hepatic protein synthesis was studied in the regenerating liver after partial hepatectomy (HTX). Hepatocellular protein synthesis (HPS) and secretory protein synthesis (SPS) were determined in the regenerating liver of rats after 68% HTX. The serum levels of the following items were determined in 10 patients before and after HTX: interleukin-6 (IL-6), acute-phase proteins (APP), and negative acute-phase proteins (NAPP). HPS has markedly increased after HTX, with the peak occurring at 48 hours. The regenerating rat liver showed an increase of 80% over normal livers in HPS and 200% in SPS 48 hours after HTX. A remarkable increase in IL-6 levels occurred on the first day after HTX. In all patients transient falls in APP levels occurred on the first day. Values appeared to return rapidly toward preoperative values by 3 or 5 days after HTX but failed to show any significant increase compared to preoperative values. In contrast to APP, prolonged decreases in NAPP levels occurred after HTX. Values declined to a nadir on the first or third day after HTX and remained suppressed for 14 days. These results suggest that the production of APP is activated at an early stage of liver regeneration after partial hepatectomy.

Acute-Phase Proteins↗

PubMed1993

[Effect of FK-506 on bronchial healing of canine lung allografts].

The effects of the immunosuppressive agents on the healing of the bronchial anastomosis following canine lung allo-transplantation were evaluated. Auto- or, allo-transplantation was performed in 44 dogs. The dogs were classified into following three groups: Group A (18 dogs) underwent autograft, Group B (13 dogs) underwent allograft following immunosuppressive therapy with cyclosporin A (20 mg/kg/day) orally and Group C (13 dogs) underwent allograft with FK-506 (0.1 mg/kg/day) injection intramuscularly and omentopexy on the bronchial anastomosis. The dogs were sacrificed at 1, 2, 3 or 4 weeks after surgery. The grafted lung and anastomosed bronchi were removed, and microscopic examination was performed. We estimated bronchial healing according to the inflammatory response score (IRS), which was defined as comprehensive assessment by histologic findings in each of the inflammatory response: inflammatory cell type, a degree of the proliferation of collagen fibers, edema, bleeding, degeneration and ulcer. There was no significant difference between the incidences of rejection and the inflammatory cell types. The degree of the proliferation of collagen fibers in Group C was moderate at 2 weeks and remarkable at 3 or 4 weeks. IRS at one week after operation was 9.1 +/- 1.5 in Group A, 8 in Group B and 8 in Group C. IRS at two weeks after surgery was 4.8 +/- 1.3 in Group A, 5.1 +/- 1.2 in Group B, 4.3 +/- 1.0 in Group C. IRS at three or four weeks after transplantation was 3.0 in Group A, 3.2 +/- 1.9 in Group B and 2.0 +/- 1.2 in Group C. There was no significant difference between each group and each week.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗

PubMed1993

Therapeutic effect of intradermal injections with difucosyl lactosamine (dimeric Lex) on patients with rheumatoid arthritis.

As reported by us, a new myeloid cell population with an oncofetal membrane marker, dimeric Lex (di-Lex; III3FucV3 FucnLc6), was found in the epiphyseal bone marrow adjacent to the involved joints of patients with severe rheumatoid arthritis (RA). Patients with RA received intradermal (id) injections of di-Lex incorporated in liposome or of high molecular weight glycoprotein, or tumor associated carbohydrate antigen (TCA), containing the same carbohydrate epitope as di-Lex. The epiphyseal myeloid cells were reduced or sometimes eliminated during id injection. In random trials of id injection, observation under clinical and laboratory conditions showed improvement in 63% (17/27) of the patients treated for 6 months with appropriate doses of di-Lex (III3FucnLc4), and in 72% (31/43) of those treated with an identical protocol for TCA. However, id injection with monomeric Lex had no effect.

Adult↗

PubMed1993

Optimal coupling of the left ventricle with the arterial system.

In the human the heart contracts more than 2.0 billion times during the lifetime. The total amount of energy required in this period is equivalent to lift a huge tanker (more than 200 thousand tons) above your head. Thus there is no question that the heart requires a huge amount of energy. Since minimization of energy requirements would be one of the major design goals of the cardiovascular system, we investigated energy efficiency of ventriculo-arterial coupling under various conditions. In normal conscious dogs, the arterial system extracted maximal work from the left ventricle during exercise as well as at rest. At the same time, the energy consumption of the left ventricle to support the peripheral demand was minimum. This optimal coupling condition was well maintained despite changes in blood volume. The baroreflex system appeared to play a crucial role in this optimization. In the presence of left ventricular dysfunction, however, this optimality was no longer maintained. We conclude that the efficiency of cardiac contraction is fairly well maintained under various stresses as long as left ventricular function is normal.

Animals↗

PubMed1993

Detection of postural cerebral hypoperfusion with technetium-99m-HMPAO brain SPECT in patients with cerebrovascular disease.

Seventeen of 19 patients (67 +/- 8 yr, 17 males and 2 females) had more than 75% unilateral stenosis or occlusion of the internal carotid or middle cerebral artery and two patients had carotid endarterectomy that previously had 90% stenosis of the internal carotid artery. They were studied during upright 99mTc-HMPAO brain SPECT. HMPA was injected immediately after arising from a supine position. Patients were classified into Group A (n = 10) with occlusion of the internal carotid or the middle cerebral artery or Group B (n = 9) with more than 75% unilateral stenosis of the internal carotid or the middle cerebral artery and with carotid endarterectomy. Additional cerebral blood flow perfusion abnormalities between upright and supine 99mTc-HMPAO brain SPECT were detected in seven patients in Group A and in only one patient in Group B. Semiquantitative analysis showed that the asymmetric ratios between upright and supine positions changed significantly in Group A from 0.82 +/- 0.15 to 0.89 +/- 0.10 (p < 0.01), but not in Group B, from 0.89 +/- 0.11 to 0.92 +/- 0.12 (ns). Additional perfusion abnormalities were relevant to occlusion of the internal carotid or middle cerebral artery indicated postural cerebral hypoperfusion. We conclude that upright 99mTc-HMPAO brain SPECT visualizes postural cerebral hypoperfusion possibly related to silent cerebral ischemia.

Aged↗

PubMed1993

[A case of radiation-induced chronic constrictive pericarditis developing 16 years after irradiation].

We reported a 51-yr-old female with radiation-induced chronic constrictive pericarditis. At age 29, she had received a mastectomy and postoperative irradiation because of left breast cancer. At age 45, she had syncope and was diagnosed with complete atrioventricular block and a pacemaker was implanted. At that time, pericardial thickening with effusion was noted. The following year, tricuspid regurgitation was noted. On catheter study, a dip and plateau pattern of the right ventricular pressure curve appeared. At age 50, tricuspid regurgitation worsened due to the lead wire of the pacemaker compressing the leaflet, and the pacemaker was reimplanted. However, the following year, she complained of general fatigue and dyspnea and was admitted to our hospital. On 67Ga study, diffuse accumulation in the cardiac region appeared. There was no perfusion defect detected in the left myocardium, but right myocardial damage was suspected by thallium study. In 99mTc-HSA RI angiography, right atrium dilatation appeared and a pericardial halo around the ventricles was seen. She underwent pericardectomy, tricuspid replacement and pacemaker reimplanted, but she died. On autopsy, pericardial thickening and adhesion, right myocardial fibrosis, the fibrotic change of the bundle branches were seen. We reported a case of radiation-induced constrictive pericarditis. Radionuclide studies were useful in diagnosing and following the patient.

Breast Neoplasms↗