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Biomedical subjects

H Seto

Publications and source records attributed to H Seto.

At least 91 records · Page 5Linked to original sources
PubMed1988

[The significance of early coronary reperfusion in patients with acute myocardial infarction assessed by regional wall motion].

Left ventricular ejection fraction, regional wall motion, hospital mortality rate, and reocclusion rate of the infarct-related coronary artery after thrombolytic therapy were examined in 164 consecutive patients who were admitted within 12 hours of the onsets of their symptoms of acute myocardial infarction. The patients were divided into three groups based on the findings of initial coronary angiography before and after administration of urokinase: (1) stenosed (the infarct-related coronary blood flow was visualized at initial angiography) (n = 41); (2) successfully thrombolysed (n = 82); and (3) unsuccessful (n = 41). The patients in each group were also subdivided into three subgroups based on the recanalized time (hours): within three, three to six hours and six hours or longer. The hospital mortality rates were 4.9% (two of the 41 patients) in the stenosed; 8.5% (seven of the 82 patients) in the thrombolysed; 29.3% (12 of the 41 patients) in the unsuccessful group, and 12.8% (21 of the 164 patients) overall, respectively. There were significant differences among these three groups. The incidence of pump failure as a cause of death in the acute stage was significantly low in the stenosed (two of the 41 patients) and in the thrombolysed (3 of the 82 patients) groups compared to the unsuccessful group (eight of the 41 patients). The rates of rethrombosis one month after thrombolytic treatment were 3% in the stenosed and 4% in the thrombolysed groups. On the contrary, visualization of coronary blood flow at the chronic stage (approximately one month later) was confirmed in 19% of the patients in the unsuccessful group. Left ventricular ejection fraction one month after thrombolytic therapy in the subgroup with the recanalized coronary arteries within three hours was significantly higher than that of the unsuccessful group, but, after three hours of procedure, no significant difference of left ventricular ejection fraction was present among three groups. Regional wall motion in patients with the recanalized coronary artery within 12 hours was better than that of the unsuccessful group. The area of improved wall motion was wide in patients with early recanalization in the stenosed and thrombolysed groups. Thus, early recanalization within three hours is mandatory for reducing mortality and for improving ejection fraction and wall motion.

Humans↗
PubMed1988

[Angiosarcoma of the liver and pineal region].

Angiosarcoma is a rare malignant tumor originating from vascular endothelial cells. We have experienced a case of 17-year-old man, who had angiosarcoma in the pineal region and the liver. Patient's initial symptom was headache and CT scan revealed a high density mass in the pineal region with obstructive hydrocephalus. After the radiation therapy, the tumor was disappeared completely on CT scan. One year later, he developed abdominal pain, and CT scan and angiogram revealed multiple angioma like lesions in the liver. The mass in the pineal region showed concomitant regrowth, and finally, the patient was died of abdominal hemorrhage. At autopsy, pineal tumor and hepatic tumor were both angiosarcomas, although it was uncertain which was the original tumor.

Adolescent↗
PubMed1987

LiCl treatment releases a nickase implicated in genetic transformation of Streptococcus pneumoniae.

When cells competent for genetic transformation of Streptococcus pneumoniae which could bind and enable entry of extracellular DNA molecules were treated with LiCl, they released a nickase that introduced nicks into a double-stranded DNA in the presence of EDTA. The nickase was specific for competent cells and coupled with DNA-binding activity. Furthermore, when noncompetent cells were treated with LiCl, they released the putative receptors for the competence activator.

Chlorides↗
PubMed1987

[Whole-body transmission scintigraphy using a line source].

Transmission scanning was proposed to be a useful adjunct to conventional emission scanning for accurately keying radionuclide deposition to radiographic anatomy. After introduction of a scintillation camera, transmission whole-body scintigraphy using a flood source has been performed in a patient with differentiated thyroid carcinoma. Recently immunoscintigraphy with radiolabeled monoclonal anti-tumor antibodies has become popular and transmission whole-body scintigraphy has been re-evaluated to make diagnosis for laterality of metastases. However, there are several problems to handle a flood source for preparation and shielding. We developed a special line source for transmission whole-body scintigraphy. The line source is composed of a plastic tube (inner diameter: 3 mm) with three-way stop in a U-shaped metal. There are several advantages to use this line source as compared to a flood one; (1) a small volume of radioactive solution (less than 5 ml), (2) easy preparation and setting, and (3) less radiation. Moreover good quality of transmission image is obtained using this line source.

Humans↗
PubMed1987

[Attenuation correction of SPECT imaging by dual energy method--quantification of 111In-labeled monoclonal anti-tumor antibody localization].

Application of radiolabeled monoclonal anti-tumor antibodies for diagnosis and therapy has made remarkable progress in the past few years. Quantification of radiopharmaceutical localization is required adequate attenuation correction in SPECT imaging. Attenuation correction by transmission CT (TCT) data is one of the best method at present time. However, if a patient is moved between TCT and SPECT, this method is no more applicable. We developed a new attenuation correction algorithm by dual energy method, using 99mTc and 111In because of similarity of these linear attenuation coefficients. The new algorithm uses data of TCT with an external source of 99mTc, and requires another data from SPECT of 111In labeled monoclonal anti-tumor antibody, which are simultaneously obtained. TCT results in an attenuation map, which then serves as input into the final intrinsic correction algorithm to uncorrected SPECT data. In chest phantom experiment, the attenuation corrected SPECT images revealed nearly same distribution of actual radioactivity of 111In as compared to that of uncorrected one.

Antibodies, Monoclonal↗
PubMed1987

In vivo localization of radiolabeled monoclonal antibody to carcinoembryonic antigen (CEA) in a CEA-producing tumor--comparison with polyclonal antibody.

To compare accumulation of the 125I-labeled antibodies (anti-carcinoembryonic antigen (CEA) monoclonal antibody and polyclonal antibody) to a CEA-producing tumor (SC-2-JCK), an in vivo localization study was performed in nude mice. The tumor-to-blood ratio at 120 hours after injection rose to 4.6 for the monoclonal antibody, but remained at 1.3 for the polyclonal antibody. However, no differences were noted between the antibodies up to 72 hours after injection. In autoradiograms, selective accumulation of the tracer was noted in the tumor for both antibodies. However, no superiority or inferiority of imaging for either of the antibodies could be definitely determined.

Adenocarcinoma, Papillary↗
PubMed1987

Arugomycin, a new anthracycline antibiotic. I. Taxonomy, fermentation, isolation and physico-chemical properties.

Arugomycin (AGM) is a new anthracycline antibiotic produced by strain No. 1098-AV2 which was identified as Streptomyces violaceochromogenes. AGM was isolated by solvent extraction, silicic acid chromatography and Sephadex LH-20 column chromatography. Acid treatment of AGM gave the chromophore, named arugorol, which was identified as 4'-epi-nogalarol, and sugar moieties. AGM inhibited the growth of Gram-positive bacteria and showed antitumor activity against sarcoma S-180 and Ehrlich ascites tumors.

Animals↗
PubMed1987

Arugomycin, a new anthracycline antibiotic. II. Structural elucidation.

The structure of arugomycin was determined by chemical degradation, and NMR and mass spectral analyses to be a new anthracycline antibiotic with arugorol (4'-epi-nogalarol) as the chromophore and two sugar chains comprising diginosyl-decilonitrosyl-2-deoxyfucose, and (4-O-fumaryl-diginosyl)-diginosyl-2-deoxyfucosyl -diginose.

Anthracyclines↗
PubMed1987

Arugomycin, a new anthracycline antibiotic. III. Biological activities of arugomycin and its analogues obtained by chemical degradation and modification.

Biological activities of arugomycin and its analogues obtained by chemical degradation and modification were evaluated. Differences in the sugar moieties affected their biological activities including induction of differentiation of mouse Friend erythroleukemia cells and mouse myeloid leukemia cells, antitumor activities against sarcoma S-180, Ehrlich ascites carcinoma and P388 leukemia, and cytotoxicity against murine leukemia cells. Some relationships were found between the sugar moieties and biological activities.

Animals↗