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K Hayashida

Publications and source records attributed to K Hayashida.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Assessment of left ventricular function by 201Tl ECG-gated myocardial SPECT].

We applied the QGS program for LV function analysis (described by Germano, 1995) to a 201Tl SPECT study at rest, and estimated its accuracy. We performed 201Tl ECG-gated myocardial SPECT in 25 patients with ischemic heart disease under an acquisition time used in the routine 99mTc ECG-gated SPECT study. The quality of the gated images was visually assessed with a 4-point grading system. LVEDV, LVESV, LVEF determined by the QGS program were compared with those by Simpson's method on biplane LVG in 25 patients. Regional wall motion scores in 7 myocardial segments were assessed on the three-dimensional display created by the QGS program and the cine display of biplane LVG with a 5-point grading system. Wall motion scores obtained by the QGS program were compared with those by LVG. Although 72.0% of 201Tl ECG-gated SPECT images were fair or poor in image quality, there were good correlations between the values obtained by the QGS program and LVG (LVEDV: r = 0.82, LVESV: r = 0.88, LVEF: r = 0.89). In addition, wall motion scores by the QGS program were correspondent to those by LVG in 77.1% of all 175 myocardial segments. We conclude that the QGS program provides high accuracy in evaluating left ventricular function even from 201Tl ECG-gated myocardial SPECT data.

Aged↗
PubMed1999

[A peculiar MRI findings in a case with slowly progressive cerebral ischemia caused by internal carotid artery stenosis possibly due to fibromuscular dysplasia].

A 47-year-old man developed progressive muscular weakness in the left arm. MR images revealed low intensity signal lesions with ring enhancement by Gd-DTPA in right fronto-parietal lobes. At that time cerebral angiography was not performed because he refused. A tuberculin skin test showed strongly positive reaction and then administration of anti-tuberculous drugs was started. His symptom had remained stable for one year, but left facial palsy and dysarthria added about two years later. MR images revealed expansion of the lesions in right parietal lobe, adding cortical high intensity signal lesions with Gd-DTPA enhancement on T1-weighted images. Angiography disclosed tubular stenosis of right internal carotid artery at the portion of cervical to petrous segment and the local stenosis at right renal artery. These lesions were considered to be caused by fibromuscular dysplasia, but not atherosclerosis, because we could not find any atherosclerotic lesions in other arteries including right carotid bifurcation. His manifesting symptoms were ascribed to slowly progressive cerebral ischemia. And peculiar MRI findings in his early stage resembled those of inflammatory granulomatous diseases.

Arterial Occlusive Diseases↗
PubMed1999

Hemodynamic changes around cerebral arteriovenous malformation before and after embolization measured with PET.

To estimate the changes in regional cerebral blood flow (rCBF) around cerebral arteriovenous malformation (AVM) before and after embolization, 6 patients with AVM were sequentially examined with positron emission tomography (PET). PET depicted the remodeling of rCBF in the ipsilateral hemisphere of AVM after embolization. Decrease of rCBF in the ipsilateral hemisphere was also detected in patients with focal symptoms before embolization, and improvement of clinical symptoms after embolization corresponded to disappearance of rCBF decrease. PET can detect hemodynamic changes after embolization, and has a possibility to estimate the effect of embolization in patients with AVM.

Adult↗
PubMed1998

Comparison of positron emission tomography study results of cerebral hemodynamics in patients with bleeding- and ischemic-type moyamoya disease.

The purpose of this study was to elucidate the difference in cerebral hemodynamics and metabolic status between patients with bleeding- and ischemic-type moyamoya disease. Regional cerebral blood flow (rCBF), regional cerebral metabolic rate of oxygen (rCMRO2), regional oxygen extraction fraction (rOEF), and regional cerebral blood volume (rCBV) in the cortex of the middle cerebral artery (MCA) territories and rCBV in the striatum were measured using positron emission tomography (PET) in 17 patients with moyamoya disease. Patients were divided into three subgroups according to type of disease manifestation and age: adult bleeding type (five cases), adult ischemic type (10 cases), and childhood ischemic type (two cases). When compared with adult controls, statistically significant reductions in rCBF and rCMRO2, elevation in rOEF in the MCA territories, and elevation of rCBV in the striatum were observed in PET studies for all three subgroups. Between the adult bleeding type and ischemic type, rCBF, rCMRO2, and rOEF in the MCA territories were not different, but rCBV in the striatum was higher in patients with ischemic-type moyamoya disease than in those with the bleeding type. In adult patients with bleeding and ischemic types, rOEF and rCBV in the MCA territories and rCBV in the striatum were significantly lower than in patients with childhood ischemic-type moyamoya disease. In adult patients with bleeding-type moyamoya disease, cerebral hemodynamics were impaired and similar to those in adult ischemic type.

Journal Article↗
PubMed1998

Soluble Fas ligand in the joints of patients with rheumatoid arthritis and osteoarthritis.

OBJECTIVE: To investigate the expression and function of Fas ligand (FasL),which can be in a membrane-bound or soluble form, in the joints of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: The concentration of soluble FasL (sFasL) in serum and synovial fluid (SF) from 24 OA and 38 RA patients was measured using an enzyme-linked immunosorbent assay. The expression of FasL on SF lymphocytes (SFL) and peripheral blood lymphocytes (PBL) was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. A cytotoxic killing assay of membrane-bound FasL and purified sFasL against cultured synovial cells was also performed. RESULTS: Soluble FasL was detected in the SF of patients with RA and OA, but not in their serum. The concentration of SF sFasL was remarkably higher in patients with severe RA than in patients with mild RA or with OA. RT-PCR showed that SFL, but not PBL, from RA patients expressed messenger RNA for FasL. Membrane-bound FasL induced apoptosis in cultured synovial cells from the RA and OA patients, but naturally processed human sFasL did not. CONCLUSION: SFL from RA patients expressed FasL, and cleaved sFasL accumulated in the SF of inflamed joints. The different killing activity of membrane-bound FasL and sFasL against synovial cells may regulate Fas-mediated apoptosis in synovial cells.

Aged↗
PubMed1998

Increased bone mineral turnover without increased glucose utilization in sclerotic and hyperplastic change in fibrous dysplasia.

Fibrous dysplasia is a benign bone disorder. It is diagnosed by distinctive X-ray radiography, CT, and MRI findings. Although bone scintigraphy helps to identify the tumor origin according to accelerated bone turnover, the glucose metabolism in fibrous dysplasia has not yet been investigated. We reported a case of fibrous dysplasia in craniofacial bone which showed signs of the acceleration of bone mineral turnover without elevated glucose utilization by Technetium-99m-HMDP SPECT and Fluorine-18-FDG PET. We concluded that the growth of fibrous dysplasia needed the acceleration of bone mineral turnover without an increase in glucose metabolism.

Bone Density↗
PubMed1998

Myocardial glucose metabolism in patients with hypertrophic cardiomyopathy: assessment by F-18-FDG PET study.

In an investigation of myocardial metabolic abnormalities in hypertrophic myocardium, the myocardial glucose metabolism was evaluated with F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in 32 patients with hypertrophic cardiomyopathy, and the results were compared with those in 9 patients with hypertensive heart disease. F-18-FDG PET study was performed in the fasting and glucose-loading states. The myocardial regional %dose uptake was calculated quantitatively. The average regional %dose uptake in the fasting state in the patients with asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy was significantly higher than that in the patients with hypertensive heart disease (0.75 +/- 0.34%, 0.65 +/- 0.25%, and 0.43 +/- 0.22%/100 g myocardium, respectively). In contrast, the average %dose uptake in the glucose-loading state in the patients with asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy was not significantly different from that in patients with hypertensive heart disease (1.17 +/- 0.49%, 0.80 +/- 0.44% and 0.99 +/- 0.45%, respectively). The patients with apical hypertrophy had also low %dose uptake in the fasting state (0.38 +/- 0.21%) as in the hypertensive heart disease patients, so that the characteristics of asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy are considered to be high FDG uptake throughout the myocardium in the fasting state. Patients with apical hypertrophy are considered to belong to other disease categories metabolically. F-18-FDG PET study is useful in the evaluation of the pathophysiologic diagnosis of patients with hypertrophic cardiomyopathy.

Blood Glucose↗
PubMed1998

Visualization of pressure-dependent luxury perfusion in a patient with subacute cerebral infarction.

Luxury perfusion characterized by depressed metabolism compared with CBF might be changed by decreasing cerebral perfusion pressure during the sitting position. A 77-yr-old man with subacute cerebral infarction was studied with brain X-ray computed tomography (CT), raise-up test with 99mTc-d,1-hexamethylpropyleneamine oxime (HMPAO) brain single photon emission tomography (SPECT) and positron emission tomography (PET). Brain X-ray CT revealed a low-density area in the left middle cerebral artery (MCA) anterior area. Raise-up 99mTc-HMPAO brain SPECT revealed decreased uptake in the left MCA anterior area in the sitting position and subsequent supine 99mTc-HMPAO brain SPECT revealed hot accumulation there. PET study in the supine position demonstrated some differences between CBF and the cerebral metabolic rate for oxygen in the left MCA anterior area, indicating luxury perfusion. CBF in the area of luxury perfusion might be decreased during the sitting or standing position and increased during the supine position by dysautoregulation of the cerebral vessels in the luxury perfusion during the subacute infarct.

Aged↗
PubMed1998

Acetazolamide induced myocardial ischemia in patients with severe coronary artery disease.

UNLABELLED: Acetazolamide (ACZ)-augmented brain SPECT is commonly used for evaluating cerebral vascular reserve in patients with cerebrovascular disease. ACZ may cause myocardial ischemia in patients with coronary artery disease. To evaluate the risk of induction of myocardial ischemia with ACZ-augmented myocardial SPECT, we performed combined ACZ-augmented Tl-201 myocardial SPECT (ACZ-myo SPECT) with Tc-99m HMPAO brain SPECT in patients with severe coronary artery disease. METHODS: Nine patients underwent combined ACZ-myo SPECT with Tc-99m HMPAO brain SPECT. (1) For qualitative analysis, SPECT images were divided into 13 segments to calculate the total defect scores. (2) Six ROIs were placed on the slices in the myocardial SPECT short-axis images and the regional uptake ratio was obtained as the ratio of the mean counts in the myocardium to the maximal count in the slice. The total defect score and regional uptake ratio of ACZ-myo SPECT were compared with those of early and delayed dipyridamole Tl-201 myocardial SPECT (DP-Tl SPECT) images. RESULTS: (1) In the 21 coronary artery territories with coronary stenosis > or = 75%, the total defect score in ACZ-myo SPECT, early and delayed DP-Tl SPECT images were 3.52 +/- 4.14*, 4.19 +/- 4.65* and 2.25 +/- 3.34, respectively (*: p < 0.05 vs. delayed DP-Tl SPECT images). (2) In 44 of 54 ROIs with coronary stenosis > or = 75%, the regional uptake ratio of ACZ-myo SPECT, early and delayed DP-Tl SPECT images were 0.670 +/- 0.166**, 0.677 +/- 0.194**, 0.721 +/- 0.178, respectively (**: p < 0.01 vs. delayed DP-Tl SPECT images). Systolic blood pressure fell at 11 min after ACZ infusion without electrocardiographic ST-T changes or chest pain. CONCLUSION: As ACZ has the potential to cause myocardial ischemia, ACZ-augmented brain SPECT should be performed with caution in patients with severe coronary artery disease associated with cerebrovascular disease.

Acetazolamide↗
PubMed1998

Use of 123I-IMP brain SPET to predict outcome following STA-MCA bypass surgery: cerebral blood flow but not vasoreactivity is a predictive parameter.

Superficial temporal artery - middle cerebral artery (STA-MCA) bypass surgery might improve the cerebral blood flow (CBF) but fail to reduce the risk of post-surgical events such as ischaemic stroke. In this study, we studied retrospectively whether the risk of post-surgical events corresponded to the change in resting CBF and/or the change in vasoreactivity observed before and after STA-MCA surgery using N-isopropyl-I-123-p-iodoamphetamine (123I-IMP) brain single-photon emission tomography (SPET). 123I-IMP brain SPET images obtained at rest and following acetazolamide challenge both before and after STA-MCA surgery were studied in 30 patients. Resting CBF was estimated semiquantitatively using the resting count ratios of the middle cerebral artery (MCA) area to the cerebellum. Acetazolamide c hallenge was assumed to result in an average increase in flow of 40% in the cerebellum. The vasoreactive response was then estimated as the ratio of the change in counts (acetazolamide - rest) to the resting cerebellar counts multiplied by 1.4. We classified 14 patients (50.5 +/- 19.3 years) into group I, who h a change in their resting CBF from before to after surgery of >10%, and 16 patients (54.0 +/- 18.8 years) into group II, who had a change in their resting CBF from before to after surgery of ¿leq10%. Oxygen-15 positron emission tomography (PET) studies were performed in five patients from group I and five patients from group II. One post-surgical event occurred in group I while there were eight post-surgical events in group II (P<0.05). Resting CBF improved by 20.4% +/- 7.5% in group I and by 0.9% +/- 6.9% in group II patients after surgery (P<0.001). No significant difference in the improvement in vasoreactivity was observed between group I patients (32.6% +/- 17.7%) and group II patients (24.6% +/- 15.6%) following surgery. Patients in the group I PET subset showed normalization of oxygen extraction fraction (OEF) from 0.59 +/- 0.09 before surgery to 0.46 +/- 0.06 after surgery (P<0.05), while patients in the group II PET subset showed no statistical difference in OEF before surgery (0.58 +/- 0.14) and after surgery (0.54 +/- 0.05). We conclude that the outcome of STA-MCA bypass surgery can be predicted by the improvement in resting CBF but not by the improvement in vasoreactivity.

Acetazolamide↗
PubMed1998

Propylthiouracil-induced severe hepatitis: a case report and review of the literature.

A 21-year-old woman was diagnosed as having Graves' disease in April, 1995. Thiamazole was administered; about a month later the patient had a skin rash and propylthiouracil (PTU) was given instead. Two months after commencing PTU, she rapidly developed jaundice, accompanied by severe liver damage. The drug-induced lymphocyte stimulating test was positive for PTU and she was diagnosed as having severe hepatitis induced by PTU. After pulse therapy with 500 mg of methylprednisolone was given for 3 days, liver function test results were gradually improved, and became normalized 1 1/2 months after admission. The pathology findings of the liver biopsy sample taken before administration of corticosteroid showed necrosis of hepatocytes predominantly around the central veins (i.e., zone 3 necrosis), and moderate to severe infiltration of lymphocytes and neutrophils in portal areas and lobules. Severe hepatic damage due to PTU is rare; 25 cases have been reported so far in the English-language literature. When we use PTU for patients with hyperthyroidism, we should keep in mind that severe liver damage induced by PTU can be fatal, and we should therefore diagnose it earlier by liver biopsy and lymphocyte stimulating test.

Adult↗
PubMed1998

Arthroscopic Bankart suture repair for traumatic anterior shoulder instability: analysis of the causes of a recurrence.

Eighty-two patients with traumatic anterior shoulder instability were treated with an arthroscopic transglenoid multiple suture technique (Caspari's method) and followed-up for more than 2 years. A retrospective analysis of the clinical outcome was performed to determine the factors related to poor results. The mean age at operation was 21 years (range, 13 to 50 years) and the mean follow-up period was 40 months (range, 24 to 70 months). According to the status of the ligament-labrum complex and the glenoid bone defect, the Bankart lesions were classified into five types arthroscopically. There were 21 shoulders of type 1, 33 shoulders of type 2, 22 shoulders of type 3, and 6 shoulders of type 5. Twenty-four of the patients played contact sports before the operation. The clinical outcome was assessed by Rowe's criteria (1978). To analyze the factors related to a poor outcome, a multivariate analysis was done to assess the influence of 12 clinical factors (age at operation, age at first dislocation, sex, dominant side, disease duration, number of dislocations, sporting activity before operation, inferior joint laxity, thickness of the ligament-labrum complex, type of Bankart lesion, number of sutures, and method of suture fixation). Fifty-five of 82 patients had an excellent outcome, 14 had a good result, and 13 had a poor result. According to postoperative instability, redislocation was seen in 13 patients (16%), resubluxation in 2 patients (2%), with a recurrence rate of 18%. The mean limitation of external rotation at 90 degrees abduction was 6.0 degrees (range, 0 degrees to 30 degrees), and there was a 10 degrees loss of external rotation in 10 patients. The factors significantly related to recurrence were a type 3 Bankart lesion, playing contact sports preoperatively, a thin ligament-labrum complex, and repair with less than four sutures. In conclusion, a 18% rate of recurrence is not acceptable. To obtain a better clinical outcome, very careful selection of patients for this technique is necessary. Our analysis of the factors related to a poor outcome may help to decide what the proper indications are for this technique.

Adolescent↗
PubMed1998

Reversible ischemia in hippocampal areas by retrograde cerebral circulation surgery for thoracic aortic aneurysm with Tc-99m ECD brain SPECT.

Because hippocampal neurons are quite vulnerable to the anoxic brain injury that sometimes occurs in aortic arch surgery in humans, hippocampal ischemia should be a sensitive indicator of global cerebral ischemia. It was concluded that the hypothermic retrograde cerebral circulation technique for aortic arch surgery could not only be performed safely with respect to the brain, but could also increase blood flow to the hippocampal areas, probably as a result of restoration of blood flow in the thoracic aorta.

Adult↗
PubMed1998

Decreased hippocampal blood flow related to memory impairment after cardiovascular surgery: assessment by reconstructed SPECT parallel to the longitudinal axis of the hippocampal formations.

Hippocampal damage has been linked to memory impairment. To clarify the relationship between decreased hippocampal blood flow and memory impairment in patients after cardiovascular surgery, the authors compared Tc-99m HMPAO SPECT findings and Mini Mental State Examination (MMSE) scores. Eight patients who had valve replacement, two who underwent aorto-coronary bypass, two who had aortic aneurysm replacement and one who had a ventricular septal defect closure were included in this study. Cerebral perfusion was estimated using reconstructed tomographic images, which were parallel to the longitudinal axis of the hippocampal formations. The hippocampal uptake ratios of Tc-99m HMPAO were calculated and normalized to that of the cerebellum. In three patients whose MMSE score decreased after surgery, the hippocampal uptake ratio was significantly reduced (0.69 +/- 0.09) compared with the remaining 10 patients whose MMSE scores did not decrease after surgery (0.91 +/- 0.02). These data suggest that SPECT imaging parallel to the longitudinal axis of the hippocampus is sensitive to decreased hippocampal blood flow, and decreased hippocampal blood flow is related to memory impairment in some patients after cardiovascular surgery.

Adolescent↗
PubMed1998

Pharmacologic profile of TA-606, a novel angiotensin II-receptor antagonist in the rat.

This study was carried out to characterize a novel angiotensin II-receptor antagonist, TA-606, (3-pentyloxy) carbonyloxymethyl-5-acetyl-2-n-propyl-3-[2'(1H-tetrazole-5-yl) biphenyl-4-yl]methyl-4,5,6,7-tetrahydro imidazo [4,5-c] pyridine-4-carboxylate hydrochloride, which is a newly synthesized prodrug of 606A. In anesthetized rats, 606A inhibited angiotensin II-induced pressor response with a median inhibitory concentration (IC50) of 6 microg/kg, i.v., and was 8 times more potent than EXP3174, an active metabolite of losartan. Bioavailability of TA-606 was 11 times higher than that of 606A in Sprague-Dawley rats, with consistent hypotensive potencies in spontaneously hypertensive rats (SHRs). In conscious renal hypertensive rats (RHRs) and conscious SHRs, TA-606 lowered the blood pressure without any effects on the heart rate, and its effective dose for 30 mm Hg (ED30) values were 0.14 and 0.21 mg/kg, p.o., respectively. The effect of TA-606 lasted > 10 h in both models. Moreover, the effect of TA-606 was approximately 30 and 10 times more potent than those of losartan in RHRs and SHRs, respectively. TA-606 did not affect the blood pressure in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. TA-606 given for 12 weeks attenuated the development of hypertension in stroke-prone SHRs. These results indicate that TA-606 is a potent angiotensin II-receptor antagonist with antihypertensive efficacy. Thus TA-606 is suggested to be a possible useful agent in the treatment of hypertension.

Angiotensin Receptor Antagonists↗
PubMed1998

Baumkuchen map analysis to detect postural cerebral hypoperfusion with upright 99Tcm-HMPAO brain SPET.

We have evaluated a polar cortical flow Baumkuchen map (BK map), constructed from projection data by inwardly layering cortical flow stripes from the base to the apex, to detect postural cerebral hypoperfusion using 99Tcm-HMPAO brain SPET. A circular cortical perfusion outline was constructed from sinogram data at a 20% threshold; a ring was then formed by constructing an inner line with a radius equal to half that of the outer line. This ring on the transaxial image was superimposed onto the cortical image, then divided into 60 portions at 6 degrees intervals from the centre. The maximal number of counts per pixel within each sector was determined, translated into polar coordinate profiles and displayed as a polar map. We studied 11 patients with unilateral stenosis of the internal carotid artery or middle cerebral artery (MCA) and 7 patients without stenosis, using upright and supine (rest) 99Tcm-HMPAO brain SPET Cerebral perfusion was visibly altered on the BK maps of all 11 patients with arterial stenosis and on the transaxial images of 8 of them. A semi-quantitative analysis of the BK maps using a ratio of the counts in the regions of interest over the right and left MCA areas, showed that the mean of the ratios was significantly lower in the upright images than in the upright + rest and rest images (P = 0.0044 and 0.0033, respectively). Although the difference in the means of the ratios between the upright and upright + rest images was significant for both the BK map and transaxial image data (P = 0.0044 and 0.0051, respectively), the BK map was accurate in detecting changes in perfusion in the upright position. We conclude that BK map analysis is useful for detecting changes in patients examined using upright brain SPET.

Adult↗
PubMed1998

Aspirin renography in diagnosis of unilateral renovascular hypertension.

We previously proposed that aspirin can enhance the diagnostic sensitivity of renography with [123I] orthoiodohippurate (OIH) in patients with suspected unilateral renovascular hypertension (RVH). In this study we assessed the sensitivity and specificity of this method. Twenty-four patients, 14 with unilateral RVH and 10 with essential hypertension, were studied. For all patients with RVH, definitive diagnosis was based on the results of angiography and the response to renal arterial angioplasty after this study. For all patients with essential hypertension, we confirmed that there was little if any stenosis of the renal artery by digital subtraction angiography or Doppler sonography. Renography with [123I]OIH or 99mTc-mercaptoacetyltriglycine (MAG3) was done once before and once after the oral administration of aspirin (20 mg/kg). We considered renal blood flow to be decreased if the time to the peak in renography was 5 min or more, and defined the peak times of the kidneys as different if separated by 2 min or more. Unilateral RVH was diagnosed when both criteria were met. Renography before aspirin administration indicated RVH in 7 of the 14 patients with RVH, and renography after aspirin indicated RVH in 13 of the 14 patients. Of the 10 patients with essential hypertension, renography before and after aspirin administration showed no difference between the kidneys in 8 patients. Thus, aspirin renography increased the sensitivity from 50% to 93%, but did not change the specificity (80%) in the diagnosis of RVH. These results suggest that renography with [123I]OIH or 99mTc-MAG3 for the diagnosis of unilateral RVH is more sensitive when aspirin is used.

Adult↗