Biomedical subjects
Publications and source records attributed to H Seto.
Epidural tuberculomas of the spine have been reported only rarely during the past few decades. A case of a surgically treated epidural tuberculoma of the thoracic spine in a 76-year-old women is presented.
A rare case of a lymphoproliferative lesion in the hypoglossal nerve is reported. The patient, a 52-year-old woman, had symptoms identical with those of hypoglossal neurinoma. Computed tomography and magnetic resonance imaging revealed a lesion at the left cerebellomedullary angle. The tumor was removed, and histopathological studies revealed that the tumor consisted predominantly of lymphocytes.
Three phenolic compounds were isolated from the roots of Arnebia euchroma as inhibitors of in vitro prostaglandin biosynthesis. Two known compounds were identified as shikonofurans and des-O-methyllasiodiplodin. The other new compound was named arnebinol and its structure was elucidated as a novel ansa-type monoterpenylbenzenoid derivative.
Two quinonic compounds, arnebinone and arnebifuranone, were isolated from the roots of Arnebia euchroma and their structures were elucidated on the basis of spectral evidence. Arnebionone is a monoterpenyl-benzoquinone in which the monoterpene moiety forms a fused ring to the benzoquinone. Arnebifuranone is another monoterpenylbenzoquinone with a furan ring containing side chain which is bonded to the benzoquinone at the head carbon of C10 moiety originating from the geranyl moiety of geranylhydroquinone.
An attempt was made to estimate noninvasively portal pressure (PP) in patients with chronic liver disease, using the theory of quantification, a kind of multivariate analysis. Forty-one patients with liver cirrhosis and 22 patients with chronic hepatitis in whom hepatic venous catheterization had been performed were studied. Seventeen parameters (age, sex, mean blood pressure, red blood cell count, platelet count, prothrombin time, lactate dehydrogenase, alkaline phosphatase, total bilirubin, albumin, gamma-globulin, indocyanine green retention at 15 min, blood urea nitrogen, hepatomegaly, splenomegaly, ascites and edema) were selected for the estimation of PP. The estimated PP correlated significantly with the data obtained by hepatic venous catheterization with a high correlation coefficient of 0.835 (p less than 0.01). An investigation using the theory of quantification was also undertaken to determine which of the 17 parameters selected above was most useful in estimating PP. Among the 17 parameters indocyanine green retention at 15 min, red blood cell count, prothrombin time, hepatomegaly and splenomegaly seemed to contribute significantly to the estimation of PP. When the formula was applied to 31 successive patients with chronic liver disease (external samples), the correlation between the estimated and measured PP was 0.455 (p less than 0.01). These results indicate that the formula is clinically useful in estimating PP in patients with chronic liver disease.
A rare case of intracranial hemangiopericytoma associated with a large cyst was treated by gross total removal and local irradiation. The tumor has not recurred for 16 months, although the effectiveness of radiation therapy for hemangiopericytoma is unclear. Histological examination of the tumor specimen showed aggregation of the microcystic components, possibly contributing to the cyst formation. Hemangiopericytoma should not be classified as meningioma because of the different neoplastic and cytological properties. Complete surgical removal is essential for this tumor because of its malignancy.
We performed echocardiographic studies in 189 elderly subjects aged over 65. Aortic regurgitation (AR) was detected by real time 2-D Doppler system. 189 patients were classified into 5 groups based on the severity of AR (AR-: 81 pts, AR1+: 32 pts, AR2+: 44 pts, AR3+: 27 pts, AR4+: 5 pts). The diameter of the aortic root, the angle (theta) between the aortic wall and interventricular septum and echo intensity of aortic valve were measured by 2-D echocardiography. There was no relation between the severity of AR and angle theta. Diameters of aortic root were significantly increased in AR3+ cases as compared with AR- and AR2+. Systolic blood pressure was significantly increased in AR4+ cases as compared with AR-, AR1+, and AR2+. Diastolic blood pressure was also decreased in AR3+ cases as compared with AR-. Echo intensity of aortic valve was increased in patients with AR. It was thought that increased diameters of the aortic root in patients with severe AR were induced from the long-standing AR, and that increased systolic blood pressure and decreased diastolic blood pressure in severe AR were caused by hemodynamic changes due to AR. Therefore, we concluded that AR in the elderly was caused by degeneration and/or deformity of the aortic valve.
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A complex of new isotetracenone group antibiotics was isolated from the cultured broth of Streptomyces sp. 2238-SVT4. It consisted of four related compounds, designated hatomarubigins A, B, C and D, whose structures were elucidated by NMR spectral analysis including a variety of 2D techniques. They enhanced the cytotoxicity of colchicine against multidrug-resistant tumor cells.
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Two cytotoxic antibiotics, designated viranamycins A and B, were isolated from the culture broth of Streptomyces sp. CH41. Their structures were elucidated as new 18-membered macrolides related to virustomycin A and concanamycin A from NMR spectral analysis. Viranamycins A and B inhibited the growth of P388 mouse leukemia and KB human squamous-cell-carcinoma cells.
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A novel antibiotic, designated lydicamycin, was isolated from the fermentation broth of an actinomycete strain identified as Streptomyces lydicus. Lydicamycin was active against Gram-positive bacteria and a certain yeast, but inactive against Gram-negative bacteria.
The structure of a new antibiotic designated lydicamycin was elucidated as shown in Fig. 1 by NMR spectral analysis including a variety of 2D techniques. Lydicamycin possesses a novel skeleton containing tetramic acid and amidinopyrrolidine moieties.
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Cyclothiazomycin is a novel renin inhibitor produced by Streptomyces sp. NR0516. It was isolated from fermentation broth by extraction with butyl alcohol, QAE-Toyopearl column chromatography and preparative HPLC. Cyclothiazomycin, which was determined to be a unique polythiazole-containing bicyclic peptide, exhibited inhibitory activity against human plasma renin with IC50 being 1.7 microM.
Avidinorubicin (MW 1,214, C60H86N4O22) was isolated from the cultured broth of strain NR0576 (which was identified as Streptomyces avidinii Stapley et al.) by butyl alcohol extraction, Sephadex LH-20 column chromatography and preparative HPLC. Avidinorubicin inhibited thrombin-induced platelet aggregation with an IC50 being 7.9 microM and was determined to be a novel anthracycline possessing two units of a new aminosugar, avidinosamine, in place of two decilonitrose groups in decilorubicin.