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Biomedical subjects

T Oki

Publications and source records attributed to T Oki.

At least 253 records · Page 14Linked to original sources
PubMed1991

Fluvirucins A1, A2, B1, B2, B3, B4 and B5, new antibiotics active against influenza A virus. I. Production, isolation, chemical properties and biological activities.

Five unidentified actinomycete strains produced a series of novel antiviral antibiotics which have a unique 2,6-dialkyl-10-ethyl-3(or 9)-hydroxy-13-tridecanelactam nucleus substituted with 3-amino-3,6-dideoxy-L-talose or 3-amino-3,6-dideoxy-L-mannose(L-mycosamine). The antibiotic components exhibited potent inhibitory activity against influenza virus type A Victoria strain infection in Madin Darby canine kidney cells by the cytopathic effect reduction assay.

Actinomycetales↗
PubMed1991

Fluvirucins A1, A2, B1, B2, B3, B4 and B5, new antibiotics active against influenza A virus. II. Structure determination.

A series of structurally related antiviral antibiotics, fluvirucins A1, A2, B1, B2, B3, B4 and B5 have been isolated from the fermentation broths of five unidentified actinomycete isolates. Based on spectroscopic analysis, partial degradation experiments and 13C-enriched acetic acid-fed biosynthetic studies, their structures were elucidated to be 2.6,10-trialkyl-3(or 9)-aminoglycosyl-13-tridecanelactams.

Acetylation↗
PubMed1991

Hydramycin, a new antitumor antibiotic. Taxonomy, isolation, physico-chemical properties, structure and biological activity.

A new antitumor antibiotic hydramycin was isolated from the fermentation broth of Streptomyces violaceus P950-4 (ATCC 53807). It showed potent antibacterial and cytotoxic activity and increased the survival time of mice inoculated with P388 leukemia. A new structure related to the pluramycin group antibiotics was assigned by its spectroscopic experiments.

Animals↗
PubMed1991

[Disseminated intravascular coagulation after transurethral ureterolithotripsy: a case report].

We experienced a case of disseminated intravascular coagulation (DIC) following transurethral ureterolithotripsy (TUL). A 78-year-old woman was referred to our hospital with the complaints of fever and urinary tract infection. Urine culture showed positive E. coli and antibiotics were given. Radiologic findings revealed a left renal stone. The patient underwent TUL. After the operation acute renal failure occurred. Laboratory data revealed DIC on the next day. In spite of intensive therapy the patient died. Pathological findings showed that acute renal failure was caused by DIC. It is important that we should note the risk of DIC after TUL.

Acute Kidney Injury↗
PubMed1991

[Results of radical nephrectomy associated with regional lymphadenectomy for renal cell carcinoma].

Between January, 1975 and December, 1989, 86 patients with renal cell carcinoma received radical nephrectomy associated with lymphadenectomy at our institutions. Pathological examination revealed lymph node metastasis in 15 patients (17.4%). The incidence of lymph node metastasis increased in accordance with the aggravation of tumor stage (p less than 0.01) and grade (p less than 0.05). Patients with a rapidly growing tumor showed higher incidence of lymph node metastasis than patients with a slow growing tumor (p less than 0.01). Regional lymph node metastases were found in 3 of the 41 patients with a slow growing tumor. Since these 3 patients are surviving with no evidence of disease for 38.7 months on average, the regional lymphadenectomy was considered to have been effective for their survival. Nine of the 25 patients with a rapid growing tumor had progressive lymph node metastasis. Four of them had apparent tumor thrombi as well as lymph node metastasis, and 2 of them had distant metastasis. These patients showed poor prognosis even after operation. Lymphadenectomy was of no value to the patients with apparent tumor thrombi and/or distant metastasis.

Adult↗
PubMed1991

[Possible mechanism of production of the musical second heart sound and its clinical significance].

To investigate the predisposing factors and the clinical significance of the musical aortic component of the second heart sound (musical S2), 18 patients with musical S2 (musical group) among the consecutive 2,000 patients with phonocardiographic examination were noninvasively studied by analyzing underlying diseases, phonocardiographic findings, organic changes of the aortic valve, severity of aortic regurgitation and left ventricular dysfunction. Organic changes of the aortic valve were assessed by two-dimensional echocardiography, and aortic regurgitation was assessed by color Doppler flow imaging. Twenty-two normal subjects (normal group) and 17 patients with essential hypertension (hypertensive group) served as controls. Mean ages were matched among the three groups. 1. Left ventricular dilatation (seven patients) and hypertension (six patients) were the dominant part of underlying disease in the musical group. 2. Musical S2 was classified in the following two types based on the phonocardiographic characteristics; musical vibrations followed immediately after the accentuated S2, and the S2 which was replaced by regular vibratory waves. 3. Frequency of the musical vibrations ranged from 120 to 200 Hz, and its duration ranged from 60 to 120 msec. Amplitude of the musical vibrations decreased by inhalation of amyl nitrite, but increased by infusion of methoxamine. In a case with mild rheumatic valve disease, methoxamine induced marked intensification of the amplitude and prolongation of the duration of the musical vibrations, finally giving a typical cooing murmur. 4. Echo intensity of the aortic valve tended to be higher in the musical group than in the other two groups. 5. Echocardiographically, aortic regurgitation appeared more frequently in the musical group (88%) than in the normal (36%) and hypertensive (41%) groups. Area of the aortic regurgitant signal was significantly larger in the musical group (4.1 +/- 1.4 cm2) than in the normal (1.2 +/- 0.8 cm2) and hypertensive (2.3 +/- 1.2 cm2) groups. 6. Left ventricular end-diastolic dimension was significantly larger in the musical group (5.8 +/- 0.6 cm) than in the normal (4.7 +/- 0.5 cm) and hypertensive (4.8 +/- 0.7 cm) groups. Fractional shortening of the left ventricle was significantly smaller in the musical group (26 +/- 10%) than in the normal (37 +/- 5%) and hypertensive (37 +/- 8%) groups. In a case of the musical group, musical vibrations following the S2, which was large in amplitude at the state of heart failure, decreased markedly after the recovery from heart failure.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1991

[Transesophageal echocardiographic study on systolic flow pattern of the pulmonary vein in patients with mitral stenosis and atrial fibrillation].

To determine the clinical significance and effect of cycle length on systolic backward (C) and forward (S) flow patterns of the pulmonary vein, we performed transesophageal and transthoracic echocardiography in patients with atrial fibrillation (Af). Study population consisted of 10 patients with mitral stenosis and sinus rhythm (MS-SR), 15 with MS and Af (MS-Af), 15 with mitral valve replacement and Af (MVR-Af), 10 with Af without organic heart disease (lone-Af) and 15 normal subjects. Various parameters, including peak velocities of C and S waves, closing amplitude of anterior mitral valve echogram during end-diastole, amplitude of the mitral annulus and interatrial septal motion during systole and left atrial pressure during the mitral closing period or end-diastole, were measured in each group. Results were as follows: 1. C wave was observed in all Af groups and six of 10 patients with MS-SR. Particularly, peak velocity of the C wave in MS-Af group was increased significantly compared with those of every other group. 2. Peak velocity of S wave in all Af groups, particularly in MS- and MVR-Af groups, decreased significantly compared with that of the normal group. 3. There were significant negative correlations between preceding R-R interval and peak velocity of the C wave or closing amplitude of anterior mitral valve echogram or left atrial pressure during end-diastole in MS-Af group. 4. There were significant positive correlations between preceding R-R interval and peak velocity of the S wave or amplitude of the mitral annulus or interatrial septal motion during systole in MS-Af group. 5. Peak velocities of the C and S waves had no correlations to preceding R-R interval in lone-Af group. We concluded that the C and S waves of pulmonary venous flow velocity pattern in MS-Af are affected by cycle length, and that the former is influenced by left atrial pressure and/or pliability of the mitral valve during the mitral closing period, and the latter by the grade of left atrial dilatation and/or preceding left atrial emptying.

Adult↗
PubMed1991

[A case of infiltrative transitional cell carcinoma of the kidney with hypercalcemia].

A 73-year-old man was admitted to our hospital with chief complaint of macrohematuria. Computerized tomography revealed enlargement of right kidney, tumor thrombi and lymph nodal involvement. Distant metastases were found in liver, lung and pelvis. We performed conservative therapy including right renal embolization. However, serum calcium levels continued to increase. Patient died from renal failure and pneumonia after 2 months, and autopsy was performed. Histological examination revealed infiltrative transitional cell carcinoma of the right kidney. PTH like peptide was measured 1 ng/gram wet tissue from the primary tumor and 16.6 ng/gram wet tissue from the metastatic liver tumor.

Aged↗
PubMed1991

[Evaluation of pulmonary venous flow pattern in hypertrophied and dilated hearts: a study with transesophageal pulsed Doppler echocardiography].

In order to evaluate the clinical significance of pulmonary venous flow (PVF) pattern, transesophageal pulsed Doppler echocardiography (TEE) was performed in 25 patients with hypertrophied heart (all with hypertrophic cardiomyopathy), 15 patients with dilated heart (10 with old myocardial infarction and 5 with dilated cardiomyopathy) and 10 normal controls. Parameters obtained from the PVF pattern were compared with those of transmitral flow (MVF) pattern, % fractional shortening (%FS) of left ventricle (LV) and amplitude of mitral anular motion (MAM) during a cardiac cycle. Results were as follows: 1. PVF pattern in cases of sinus rhythm was divided into four components, atrial systolic backward flow (PVA), ventricular systolic (PVS1, PVS2) and diastolic (PVD) forward flows. 2. In patients with dilated heart, peak velocities of PVS1 and PVS2 were markedly decreased compared with those of hypertrophied and normal hearts. 3. Peak velocity of PVD in hypertrophied and dilated hearts was significantly decreased compared with that of normal controls, and PV-D/S (ratio of peak velocity of PVD to PVS2) was significantly lower in hypertrophied heart than in normal controls. 4. Time interval from the first heart sound to the peak of PVS2 (TS) was significantly longer in dilated heart, and time interval from the second heart sound to the peak of PVD (TD) was longer in hypertrophied heart than in the other two groups. 5. MAM and %FS of dilated heart were significantly lower than those in normal and hypertrophied hearts, and peak velocity of PVS2 in dilated heart group correlated well with MAM or %FS. 6. There were significant correlations among the diastolic parameters from PVD of PVF (peak velocity of PVD, PV-D/S) and early diastolic wave (D) of MVF (peak velocity, deceleration time and deceleration of rapid filling). 7. In a case of hypertrophic cardiomyopathy with mid-diastolic wave of MVF, distinct forward wave was observed after PVD of PVF, and this wave coincided in timing with the mid-diastolic wave of MVF. 8. In a case of extensive myocardial infarction with the development of severe LV dysfunction and with "normalized" pattern of MVF, peak velocities of PVD and PVA were markedly increased, and that of PVS2 was decreased. However, the peak velocities of PVD and PVA were decreased, and that of PVS2 was increased with the fair improvement of LV dysfunction and with the compensatory augmentation of atrial contraction wave (A) of MVF.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Pradimicin A inhibition of human immunodeficiency virus: attenuation by mannan.

The mechanism of action of a novel anti-HIV antibiotic, pradimicin A, has been studied using cell-free (MT-4 cells) and cell to cell (MOLT-4 and MOLT-4/HIVHTLV-3B cells) HIV infection systems. The data indicate that (1) preincubation of the cells with HIV at 0 degrees for 1 hr, followed by the addition of pradimicin A and further incubation at 37 degrees, resulted in a complete inhibition of infection while preincubation at 37 degrees did not. Similar data were obtained with the coculture between MOLT-4 and MOLT-4/HIV cells. (2) Virus treated with pradimicin A followed by washing did not show any inhibition on subsequent HIV binding to cells. (3) The inhibitory effect of pradimicin A on HIV infection was prevented by mannan but not by other sugars tested. Mannan, however, did not interfere with the anti-HIV activity of other known inhibitors. (4) Use of EGTA suggested that pradimicin A required Ca ions to exert its anti-HIV activity. These data imply that pradimicin A inhibits an early step in HIV infection, probably through its binding to mannose residues of HIV glycoprotein.

Anthracyclines↗
PubMed1990

Fluoronaphthyridines and quinolones as antibacterial agents. 2. Synthesis and structure-activity relationships of new 1-tert-butyl 7-substituted derivatives.

A number of 7-substituted-1-tert-butyl-6-fluoroquinolone-3-carboxylic acids and 7-substituted-1-tert-butyl-6-fluoro-1,8-naphthyridine-3-carboxylic acids have been prepared and tested for antibacterial activities. Among those the 7-aminopyrrolidinyl 20b and the 7-diazabicyclo naphthyridine 18b are the most potent compounds in vitro and in vivo. Physicochemical data and acute toxicity are also discussed. Compound 18b, BMY 40062, exhibits the most favorable overall properties, considering in vitro and in vivo microbiological activity, its low toxicity, and pharmacokinetic profile, and was selected for clinical evaluation.

4-Quinolones↗
PubMed1990

DNA intercalation and cleavage of an antitumor antibiotic dynemicin that contains anthracycline and enediyne cores.

Dynemicin is a hybrid containing anthraquinone and enediyne cores, which contribute to binding and cleavage of DNA, respectively. DNA strand scission by the antitumor antibiotic is significantly enhanced by the addition of NADPH or thiol compounds. The preferential cutting site of dynemicin is on the 3' side of purine bases (i.e., 5'-GC, -GT, and -AG) and is clearly different from the cutting sites of esperamicin and calicheamicin. The double-stranded and the stem regions of single-stranded DNAs are preferentially cleaved by dynemicin. Therefore, dynemicin may be a useful reagent for probing secondary structures of DNA. Pretreatment of DNA with Adriamycin and actinomycin D alters the cutting mode of dynemicin. Dynemicin-mediated DNA breakage is strongly inhibited by pretreatment of the DNA with distamycin A and anthramycin, suggesting that dynemicin interacts with the minor groove of the DNA helix. Intercalation of the anthraquinone core into the DNA followed by the attack of the phenyl diradical formed from the enediyne core is considered as a possible mechanism of action of dynemicin.

Anthraquinones↗
PubMed1990

[A clinico-pathological study of small renal cell carcinoma].

Between 1960 and 1989, 50 patients with small renal cell carcinoma measuring below 3 cm in diameter were examined. Among them, 31 patients were nephrectomized, but in 19 patients, the renal cell carcinoma was found first at autopsy. The average tumor diameter of the unrecognized ones was smaller than that of nephrectomized patients with the minimum of 0.4 cm. Forty-one patients had clear cell carcinoma, 9 granular cell carcinoma, 40 grade 1 tumor, and 10 grade 2 tumor. The grade 3 tumor was not found in our study. Three out of the 50 patients had distant metastasis at the time of operation or autopsy. Six patients had microscopic tumor thrombi just close to the tumor pseudo-capsule. Two patients had apparent tumor thrombi in the main renal vein. The smallest tumor that showed microscopic tumor thrombi measured 1.5 cm in diameter. The incidence of tumor thrombi was correlated with tumor diameter. The step sections by 4 mm thick of nephrectomized specimens were examined on 16 patients. The daughter tumor was found in two patients. The tumor thrombi had close relationships with the presence of distant metastasis (p less than 0.001) and/or the daughter tumor (p less than 0.01). In conclusion, small renal carcinoma measuring less than 1.5 cm in diameter was considered to be treated by conservative surgery.

Adult↗
PubMed1990

New antifungal antibiotics pradimicins FA-1 and FA-2: D-serine analogs of pradimicins A and C.

Pradimicin FA-1 was produced via directed biosynthesis with substitution of D-serine for D-alanine in the 15-position of pradimicin A. This substitution was achieved by the addition of D-serine to the culture medium of Actinomadura hibisca P157-2. Likewise, pradimicin FA-2 was co-produced along with pradimicin FA-1 when the pradimicins A and C producing strain, A. hibisca A2493 was grown in D-serine-supplemented medium. The new pradimicin analogs share a common core structure of 5,6-dihydrobenzo[a]naphthacenequinone substituted by D-serine at C-15, but differ in the disaccharide moiety at C-5. Pradimicin FA-1 has an N-methylamino sugar and D-xylose. Pradimicin FA-2 is the des-N-methyl analog of pradimicin FA-1. The in vitro and in vivo antifungal activity of the analogs was comparable to that of pradimicin A.

Amino Acids↗
PubMed1990

Water-soluble pradimicin derivatives, synthesis and antifungal evaluation of N,N-dimethyl pradimicins.

Three N,N-dimethyl pradimicins were synthesized by reductive alkylation of pradimicins A, E and FA-2 and evaluated for antifungal activity, water solubility and acute toxicity in mice. They showed in vitro antifungal activity superior to pradimicin A. N,N-Dimethylpradimicins E and FA-2 showed great improvement in water solubility and animal tolerance. N,N-Dimethylpradimicin FA-2 was effective in 3 experimental in vivo fungal infection models.

Alkylation↗