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Biomedical subjects

A Shigeta

Publications and source records attributed to A Shigeta.

At least 19 recordsLinked to original sources
PubMed1992

Enzyme-linked immunosorbent assay of CS-518, a thromboxane synthetase inhibitor, in rabbit plasma and platelets.

A competitive enzyme-linked immunosorbent assay (ELISA) was developed for determination of CS-518, a novel thromboxane synthetase inhibitor. Antisera against CS-518 were obtained from rabbits immunized with bovine serum albumin linked to CS-518 via carboxylic acid introduced into the imidazolyl ring (for ELISA-1) or via 6-carboxylic acid directly (for ELISA-2). Each of two CS-518 derivatives was conjugated to horseradish peroxidase by a N-succinimidyl ester method, and it was used as a labeled-antigen in homogeneous combination with antisera. In ELISA-1, CS-518 was detectable in a range of 5pg-1ng, and all cross-reactivities with main metabolites were less than 5%, in contrast to high affinity to the taurine and glucuronic acid conjugates of CS-518 in ELISA-2. Validity of ELISA-1 was confirmed by a high-performance liquid chromatography and ELISA-1 enabled specific determination of CS-518 in plasma samples deproteinized by methanol. When ELISA-1 was applied to determine CS-518 in platelets after oral administration to rabbits, CS-518 uptake up to maximum capacity in platelets (4.2-5.4 x 10(6) M) and slow elimination of CS-518 from platelets (T1/2 = 36-41 hr) were observed independent of CS-518 doses. These results confirm that CS-518 binds to thromboxane synthetase in platelets with high affinity.

Administration, Oral↗
PubMed1991

Simultaneous determination of gemfibrozil and its metabolites in plasma and urine by a fully automated high performance liquid chromatographic system.

Sensitive and specific methods for the simultaneous determination of gemfibrozil (Lopid), a lipid-lowering agent, and its metabolites in plasma and urine are described. The methods are based on a fully automated high performance liquid chromatographic (HPLC) system with fluorescence detection. Urine samples, diluted with acetonitrile, were directly analysed by HPLC using a flow and eluent programming method. In the case of plasma, gemfibrozil and its main metabolites were extracted from acidified samples and the resulting extracts injected into the chromatographic system. The sensitivity was approximately 100 ng/mL for gemfibrozil and its four metabolites using 0.5 mL plasma or urine. An acyl glucuronide of gemfibrozil excreted in human urine after oral administration of the drug was isolated and its structure and stability examined.

Autoanalysis↗
PubMed1990

[Usefulness of ioversol (MP-328) in angiocardiography--a multicenter comparative study with iopamidol].

A randomized, controlled study was conducted to compare the radiographic efficacy, safety and usefulness of ioversol and iopamidol in 146 patients undergoing angiocardiography at six institutions. The hemodynamic and electrocardiographic effects were clinically insignificant and comparable for both agents. Ioversol demonstrated lower incidence of adverse reactions and less heat sensation in left coronary arteriography than those with iopamidol. Overall radiographic efficacy with ioversol was slightly better than with iopamidol, according to the evaluation by both investigators and committee members. Ioversol appears to be very useful for angiocardiography. This comparative study demonstrated the value of safety and efficacy evaluation criteria suggested by the preceding clinical trial with ioversol.

Adult↗
PubMed1990

[Preliminary study and clinical evaluation method of ioversol in angiocardiography--establishment of safety evaluation parameters and reliability of radiographic quality evaluation].

A multi-center clinical study of a new nonionic iodinated contrast medium (ioversol) was performed in 26 patients undergoing left ventriculography (LVG) and coronary angiography (CAG) at four centers. The aims of this study were to try to establish a clinical evaluation method on contrast media in angiocardiography and to determine radiographic efficacy and safety of ioversol. The reliability of the method evaluating the radiographic quality of the contrast medium was also examined with statistical analysis. Excellent radiographic efficacy was observed with ioversol and morphological diagnosis was possible in all cases. The electrocardiograms (ST-segment deflection, T-wave amplitude, QT interval, corrected QT interval, arrhythmia and heart rate) and the hemodynamic parameters (left ventricular systolic and end diastolic pressures, left ventricular dp/dt max, aortic systolic and diastolic pressures) indicated no clinically significant changes. This study suggested that the monitoring of the ECGs and hemodynamic parameters for up to three minutes after injection of the contrast medium is sufficient for the evaluation in LVG and CAG, and that the monitoring in CAG during the first injection into each left and right coronary artery is also sufficient for the purpose. Heat sensation during injection was mild. A patient had a symptom of nausea after ioversol administration, but it was mild and transient and resolved spontaneously. There were no abnormal clinical laboratory data related to ioversol. The reliability of the radiographic quality evaluated by the individual clinical investigators was considered to be high and adaptable. However, the evaluation in the blinded cinefilms by the committee members involving all investigators would be more preferable for the higher objectivity. The study results suggest that ioversol is considered to be the efficacious and safe contrast medium for the cardiovascular angiography.

Adolescent↗
PubMed1990

[Radionuclide assessment of cardiac involvement in patients with sarcoidosis].

This study was aimed to determine whether nuclear methods were useful for examining cardiac pathology and for making a decision of corticosteroid therapy in patients with sarcoidosis. Thirty six patients were divided into two groups; GpA consisted of 19 patients with cardiac sarcoidosis and abnormal ECG findings, and GpB of 17 patients with sarcoidosis without ECG abnormalities. Cardiac uptake of 67Ga-citrate in 2 and 99mTc-PYP in one of GpA was observed and steroid therapy resulted in the disappearance of the uptake. 201Tl-CL cardiac tomograms disclosed perfusion defects in 10 of 14 patients (71%) in GpA, including defects with redistribution in 8 of the 10 pts, but only one case in GpB. Radionuclide ventriculography using 99mTc-RBC revealed abnormal response of left ventricular (LV) function to exercise and LV dysfunction in GpA. These data suggest that nuclear study is a useful tool for diagnosing cardiac sarcoidosis, evaluating therapeutic effectiveness and long-term follow-up in patients with sarcoidosis.

Adult↗
PubMed1990

[Scanning electron microscopic study of rat lungs in experimental chronic paraquat poisoning].

It is well known that Paraquat (1,1'-dimethyl-4,4'-bipyridylium dichloride), used widely as a herbicide, causes a primary toxic effect in the lungs of humans and laboratory animals. This paper describes the pulmonary changes of chronic paraquat poisoning in rats, comparing scanning electron microscopic findings. Twenty-four rats were given repeated injections of 10/kg body weight paraquat intraperitoneally for 6 consecutive months, and six control rats were given 0.9% NaCl solution. The animals exposed to paraquat showed thickening of alveolar septum, inflammatory cell infiltration, interstitial fibrosis, and marked proliferation of alveolar macrophages. Among them four rats (21%) showed the typical findings of diffuse pulmonary fibrosis. Lesions were more severe at the subpleural region of the lung. The desquamation of alveolar epithelial cells and subsequent exposure of the basement membranes were observed in places. Although alveolar epithelial cells both in the type I and the type II were prolific, the type II cells showed partial loss of microvilli and projections. These findings may indicate the lowering of the type II cell function and subsequent decrease of surfactant excretion which causes respiratory insufficiency. Furthermore, alveolar macrophages showed a tendency to increase in number with progressive development of fibrosis. This tendency may support the hypothesis by Schoenberger et al., in which alveolar macrophages release both fibronectin and a growth factor for fibroblast after paraquat exposure.

Animals↗
PubMed1990

[A case of tuberculous arthritis of shoulder].

A rara case of tuberculous arthritis of right shoulder was reported. Plain X ray and CT showed bone destruction in humerus and glenoid process and soft tissue swelling with calcification was also demonstrated. T2 weighted images showed extension of abscess clearly. And extension to bone marrow was showed on CT and T1 weighted MR images.

Arthritis, Infectious↗
PubMed1990

[Long-term follow-up study of I-131 therapy for Graves' disease--index associated with late-onset hypothyroidism].

We have studied the follow-up of thyroid function in the patients with late-onset hypothyroidism and euthyroidism after I-131 therapy of hyperthyroidism. Thirty three patients who did not need the thyroid treatment until ten years after I-131 therapy were classified as euthyroid group. And eleven patients who needed the thyroid supplement of thyroid hormone for late-onset hypothyroidism were classified as hypothyroid group. Patients in both groups who required only a single dose of I-131 for successful treatment of hyperthyroidism had similar age, gland size, 24 hour I-131 uptake, pretreatment serum T3 uptake level and T4 concentration, and I-131 treatment dose. Subclinical hypothyroidism occurred in 28.6% of euthyroid group and 66.7% of hypothyroid group four months after I-131 therapy. The levels of T3 were recovered to higher than normal range at 6 months in euthyroid group, while the levels of T3 were kept within the normal range in the seventy percent of hypothyroid group. Patients who were still lower in the level of T3 uptake than normal range at 6 months had a higher incidence of late-onset hypothyroidism. Our observation showed no significant difference in the course of follow-up studies after I-131 therapy between the patients with late-onset hypothyroidism and euthyroidism.

Adult↗
PubMed1988

Embolism of massive hepatic tissue in inferior vena cava and right atrium after closed liver injury.

Embolism from liver tissue in a major vessel in coincidence with a severe injury to the liver is a rare phenomenon. We report a case of a 4-year-old boy who was involved in a traffic accident and died shortly after the accident. An autopsy revealed that an intrahepatic inferior vena caval injury was accompanied by a severe closed injury to the liver; the crushed liver fragment was driven through the lacerated wall into the inferior vena cava and almost completely occluded its lumen. The crushed liver flap further extended over into the right atrial cavity. Careful microscopic examination of the lungs showed no emboli of hepatic tissue.

Accidents, Traffic↗
PubMed1985

Long follow-up study in patients with prior myocarditis by radionuclide methods.

Ten patients with previous myocarditis were evaluated to determine cardiac conditions by T1-201 myocardial perfusion imaging and stress radionuclide ventriculography during the follow-up of 18-102 (average 56) months; the results were compared with those from ten sex- and age-matched controls. Exercise capacity by supine bicycle ergometer was reduced in patients with myocarditis. Their resting left ventricular ejection fraction (LVEF) was 57.5% +/- 3.9%, similar to that of controls. LVEF response to stress in myocarditis was abnormal with an increment of end-systolic volume, while in the controls LVEF increased significantly during stress. Seven of the eight patients with an abnormal ejection fraction response had constant T1-201 perfusion defects. This study indicates that latent left ventricular dysfunction is present in patients with prior myocarditis and that nuclear study is useful for long-term follow-up.

Adult↗
PubMed1984

CT findings of atrial myxoma.

The computed tomographic (CT) appearance of six atrial myxomas was analyzed. Five of the myxomas were located in the left atrium and one was in the right atrium. The margin of the myxoma was at least slightly lobulated in five cases and the content was inhomogeneous in all. Calcification was demonstrated in three cases. The site of attachment of the myxoma was demonstrated by CT to be the atrial septum in all cases. The CT findings correlated well with the operative findings. CT revealed prolapse of the myxoma into the ventricle in two cases. This finding was similar to echocardiographic and cineangiographic findings. It is concluded that it is possible with CT to diagnose atrial myxoma by the location and nature of the intracardiac mass and to differentiate it from thrombus.

Adult↗
PubMed1981

[Two-dimensional echocardiographic and RI angiographic features of aneurysm of the ascending aorta in patients with annuloaortic ectasia (author's transl)].

The purpose of this study was to compare the diagnostic value of two-dimensional echocardiography with that of other methods in the detection and localization of aneurysm involving the ascending aorta in patients with annuloaortic ectasia. Two-dimensional echocardiography, RI angiography, CT scan and aortography were performed in 19 patients (12 patients with Marfan's syndrome, 4 with aortitis syndrome and 3 with postoperative perivalvular aneurysm). Eight of 12 patients with Marfan's syndrome had dissection in the ascending aorta which was confirmed at surgery or autopsy. The following observations were obtained. 1) Dissection of the ascending aorta was clearly demonstrated on the two-dimensional echocardiogram in 7 patients by recording the intimal tear and flap, and in these cases the short axis two-dimensional echocardiogram of the ascending aorta was more useful in identifying the site and extent of dissection. 2) In patients with postoperative perivalvular aneurysms, RI angiography proved to be a more useful and sensitive technique in differentiating a leakage into the aneurysm from clots in the aneurysm. 3) CT scanning proved to be an insensitive technique to detect dissection of the ascending aneurysm and to differentiate a leakage from clots in the perivalvular aneurysm. From these observations, we concluded that two-dimensional echocardiography and RI angiography proved to be sensitive techniques in detecting dissection of the ascending aneurysm and evaluating a postoperative aneurysm in patients with annuloaortic ectasia.

Aortic Dissection↗