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Biomedical subjects

T Oki

Publications and source records attributed to T Oki.

At least 235 records · Page 13Linked to original sources
PubMed1992

Quartromicin, a complex of novel antiviral antibiotics. I. Production, isolation, physico-chemical properties and antiviral activity.

A strain of Amycolatopsis orientalis No. Q427-8 (ATCC 53884) was found to produce a complex of new antiviral antibiotics, quartromicin which consisted of at least six components A1, A2, A3, D1, D2 and D3. Structural studies suggested that they are a novel type of molecules unrelated to any known antibiotics. Each component of quartromicin exhibited antiviral activity against herpes simplex virus type 1, influenza virus type A and human immunodeficiency virus.

Actinomycetales↗
PubMed1992

[Characteristics of jugular venous pulse and its genesis in Ebstein's anomaly].

To clarify the characteristics of the jugular venous pulse and its genesis in Ebstein's anomaly, 6 patients with Ebstein's anomaly whose mean age was 45 +/- 9 years, and 10 normal subjects with a mean age of 27 +/- 6 years were studied by phono-mechanocardiography and echocardiography. The parameters included the relative height of the jugular "c" wave, the relative timing of the upstroke (Q-Cu interval) and the peak of the jugular "c" wave (Q-Cpeak interval), the relative timing of the upstroke of the carotid artery pulse, the relative timing of tricuspid valve closure (Q-Tc interval), the excursion of the closing motion of the anterior tricuspid leaflet (TV excursion), the distance between the anterior mitral annulus and the septal tricuspid annulus (M-T distance), the area of atrialized right ventricle (ARV area) and the maximum area of the tricuspid regurgitant signal. Among 6 patients with Ebstein's anomaly, tricuspid regurgitation was predominant in 4 and mild in the remaining 2. The results were as follows: 1. A large jugular "c" wave was observed in 4 of the 6 patients. Two patients with large ARV area had giant "c" wave. 2. The interval of the upstroke of the carotid artery pulse and that of the jugular "c" wave was about 39.2 msec. 3. The Q-Tc interval was significantly longer and the TV excursion was significantly greater in the patients than in the normal controls. 4. There was only a weak positive correlation between the Q-Cpeak interval and the Q-Tc interval. No significant correlation was observed between the relative height of the jugular "c" wave and the TV excursion. 5. There was a positive correlation between the relative height of the jugular "c" wave, the ARV area and M-T distance. 6. No obvious correlation was observed between the grade of tricuspid regurgitation and the relative height of the jugular "c" wave. These results suggest that augmentation of the "c" wave of the jugular venous pulse is characteristic of Ebstein's anomaly and that it correlates closely with the severity of displacement of the tricuspid valve and the size of the atrialized right ventricle.

Adult↗
PubMed1992

[Clinical significance of the click intervals for the diagnosis of dysfunction of the Medtronic-Hall prosthetic valve].

To investigate the clinical significance of click interval for evaluation of prosthetic valve dysfunction, 20 patients underwent Medtronic-Hall (MH) valve replacement (14 in the mitral position and 6 in the aortic position) were studied by simultaneous high-speed recordings of phonocardiogram, echocardiogram and/or Doppler echocardiogram. Two of the 20 patients, one in the mitral and the other in the aortic position, showed MH valve dysfunction. Eleven patients with normally functioning Björk-Shiley (BS) valve in the mitral position served as controls. Results were as follows: 1. There were usually 3 opening clicks (OC1, OC2, OC3) in patients with normally functioning MH valve in the mitral position. These 3 clicks coincided in timing with the beginning of opening, maximum opening and the end of sliding motion, respectively. Both OC1 and OC2 of the MH valve occurred in similar timing with those of the BS valve (A2-OC1 interval: MH = 65.4 +/- 11.8 msec vs BS = 72.3 +/- 17.2 msec; OC1-OC2 interval: MH = 31.2 +/- 7.7 msec vs BS = 27.3 +/- 6.1 msec). However, OC3 occurred significantly later in MH valve than in the BS valve (OC2-OC3 interval: MH = 32.3 +/- 7.5 msec vs BS = 16.4 +/- 3.8 msec, p < 0.01). 2. There were 2 closing clicks (CC1, CC2) in normally functioning the MH valve in the aortic position. These 2 clicks coincided in timing with the beginning and the end of the closing motion, respectively. Mean value of CC1-CC2 interval in 5 prosthetic patients with normal function was 31.0 +/- 9.6 msec. 3. A patient with malfunctioning MH valve in the mitral position showed a markedly prolonged OC1-OC2 interval, ranging from 66 to 140 msec, and she had multiple diastolic clicks after the OC2 phase. Prolonged OC1-OC2 interval was mainly caused by the delay of appearance of OC2, and it was thought to be due to temporary limitation of opening motion of the valve by valve thrombosis. 4. A patient with malfunctioning MH valve in the aortic position showed a markedly prolonged CC1-CC2 interval (100 msec), and he had a significant severe aortic regurgitation during this phase. At operation, fibrinoid thrombus was attached to the aortic annulus at the side of minor orifice of the valve. Closing motion of the valve was disturbed by this thrombus, and the completion of valve closure was markedly delayed.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

[Mitral valve prolapse associated with partial absence of commissural chordal insertion: report of two cases].

We reported 2 cases of mitral valve prolapse (MVP) associated with partial absence of the chordae tendineae. Case 1 was a 25-year-old man who was admitted to our hospital for further examinations of an apical pansystolic murmur (Levine 4/6) and the abnormal shadow on his chest radiograph. He was diagnosed as having grade 3 + mitral regurgitation (MR) by the Sellers classification and pulmonary varix by cardiac catheterization. Transesophageal echocardiography revealed MVP of the rough zone of the anterior mitral leaflet and MR blowing into the pulmonary varix. Case 2 was a 60-year-old man who was admitted to our hospital because of congestive heart failure and apical pansystolic murmur (Levine 4/6). Parasternal echocardiography revealed prolapse of both the anterior and posterior mitral leaflets and moderate MR. In both cases, absence of insertion of anterolateral commissural chordae was confirmed after surgery, and the abnormalities of chordal arrangement and insertion were considered as causes of MVP in these cases.

Adult↗
PubMed1992

[A case of simultaneous operation of coronary artery bypass and ascending aorta to bifemoral bypass for ischemic heart disease combined with bilateral leg ischemia].

A 58-year-old man was admitted to our hospital because of angina pectoris with severe intermittent claudication. Angiography showed triple-vessel disease of the coronary artery and complete obstruction of the bilateral common iliac arteries from their origins. Both femoral arteries were patent by collateral supplies. Combined revascularization of coronary and femoral arteries was performed. Coronary arteries were bypassed with in situ left internal thoracic artery, gastroepiploic artery and saphenous vein graft. Bilateral femoral arteries were bypassed with externally supported Dacron graft from ascending aorta through the preperitoneal space. The patient recovered well and postoperative angiography revealed all bypass grafts patent.

Aorta↗
PubMed1992

[A case of insulin receptor abnormality (type A)].

A sixteen year old woman came to the hospital for glucosuria and amenorrhea. Physical examination demonstrated that she had hirsutism, deepening of voice, and pigmented skin in her axillary lesion which was histologically diagnosed as acanthosis nigricans. Ultrasonography showed polycystic ovaries. A diabetic pattern of 75 g oral glucose tolerance test, very high levels of serum insulin (fasting: 320, peak: 1,220 microU/ml), and hyperandrogenism characterized by increases of urine 17-KS, serum testosterone and DHEA-S were found. Both serum insulin and insulin-receptor antibodies were found to be negative. Insulin binding to both erythrocytes and cultured skin fibroblasts were significantly decreased (about 30% of normal controls). Scatchard plot analysis demonstrated decreased number of insulin receptors to about 30% of the normal controls. We therefore diagnosed that she had insulin receptor abnormality, Type A in Kahn's classification.

Acanthosis Nigricans↗
PubMed1992

[Primary amenorrhea and hirsutism associated with hyperinsulinemia type A].

Hyperinsulinemia type A, which is a very rare disease, is often manifested in menstrual disorders and/or anovulation. Recently, a 19-year-old woman diagnosed with hyperinsulinemia and acanthosis nigricans, visited our outpatient clinic complaining primarily of amenorrhea and hirsutism. Endocrinological studies revealed normal LH and FSH levels, low estradiol (42.3pg/ml) and high androgens (testosterone: Over 150ng/ml, delta androstenedione: 4.8ng/ml) in serum. Her fasting insulin level was excessively high (over 320 microU/ml). UST showed bilateral polycystic ovaries. These data support the hypothesis of a pathogenic mechanism of ovarian dysfunction in patients with hyperinsulinemia; that is, too much insulin stimulates ovaries directly, followed by the production of androgens and the formation of polycystic ovaries. Strict dietary management of this patient failed to cause spontaneous vaginal bleeding. Progesterone administration did not cause withdrawal vaginal bleeding. These findings suggest that the higher that insulin level is, the more difficult it is to induce ovulation.

Adult↗
PubMed1992

Coffin-Lowry syndrome associated with calcium pyrophosphate crystal deposition in the ligamenta flava.

Clinical and ultrastructural study of four cases of Coffin-Lowry syndrome (CLS), a heritable disorder with peculiar facies, stooped posture, vertebral changes, and mental retardation, is reported. Three of the four cases had myelopathy caused by calcification of the ligamenta flava in early adulthood. These patients demonstrated that CLS is a calcium pyrophosphate dihydrate crystal deposition disease, and it is postulated that a metabolic abnormality in collagen and in proteoglycans are responsible for some aspects of CLS.

Adolescent↗
PubMed1991

Inhibitory effect of maternal antibody on mother-to-child transmission of human T-lymphotropic virus type I. The Mother-to-Child Transmission Study Group.

In order to evaluate the protective role of the maternal antibody against mother-to-child transmission of HTLV-I, we followed a total of 780 children born to HTLV-I carrier mothers by investigating the level of anti-HTLV-I antibody transferred in utero, decline of the maternal antibody and seroconversion in post-natal life. The anti-HTLV-I antibody was positively detected within the first 3-6 months of life and declined at 6-12 months after birth in all children. After the maternal antibody declined, seroconversion occurred in some of the children following either breast feeding or bottle feeding. The seroconversion rates of short-term (less than or equal to 6 months) and long-term (greater than or equal to 7 months) breast feeders were 4.4% (4/90 cases) and 14.4% (20/139 cases), and the rate of bottle feeders was 5.7% (9/158 cases). Long-term breast feeding yielded more seroconverters than short-term breast feeding; 14.4% (20/139 cases) vs. 4.4% (4/90 cases), RR = 3.68, p = 0.018. The seroconversion rate of short-term breast feeders was nearly equal to that of bottle feeders; 4.4% (4/90 cases) vs. 5.7% (9/158 cases), RR = 0.770, p = 0.471. When neonatal lymphocytes were cultured with breast milk cells of HTLV-I carrier mothers, the in vitro infection of HTLV-I was inhibited by the addition of HTLV-I-seropositive cord-blood plasma. Our results suggest that the maternal antibody may inhibit HTLV-I infection by short-term breast feeding but not by long-term breast feeding after decline of the maternal antibody.

Adolescent↗
PubMed1991

Calcium oscillation associated with reduced protein kinase C activities in ras-transformed NIH3T3 cells.

We show here novel intracellular Ca2+ oscillation in v-K-ras-transformed NIH3T3 cells induced by mitogenic peptide hormones, bradykinin and bombesin, as well as fetal calf serum. Induction of the Ca2+ oscillation is strongly correlated with the malignant properties and inversely with PKC activities in vitro and in vivo. These results suggest that the mitogen-induced Ca2+ oscillation is negatively regulated by PKC, which modulates Ca2+ influx in v-K-ras-transformed NIH3T3 cells.

Animals↗
PubMed1991

Isolation and monolayer culture of human fallopian tube epithelial cells.

In the present study we have established a pure monolayer culture system of human fallopian tube epithelial cells. The cells were isolated using collagenase digestion, and were cultured in Medium 199 supplemented with 15% fetal bovine serum. The epithelial cells derived from primary and secondary culture were characterized using immunocytochemical staining and electron microscopy. The cells continued to grow for 2 to 3 wk once the monolayer culture of the cells was established. It is currently possible to maintain the cultures until the third generation. Proliferation of these cells was enhanced by epidermal growth factor but not by basic-fibroblast growth factor, insulin, transferrin, estradiol-17 beta, or progesterone. This culture system offers a good model for determining characteristics of the tubal epithelium and would permit effective study of co-culture with embryos.

Adult↗
PubMed1991

In vitro and in vivo antifungal activities of BMY-28864, a water-soluble pradimicin derivative.

BMY-28864, a water-soluble pradimicin derivative, had potent in vitro activity against a wide variety of fungi, including those associated with deep-seated mycosis; it inhibited the growth of standard strains and clinical isolates at concentrations of 12.5 micrograms/ml or less. At the MIC or higher concentrations, BMY-28864 was fungicidal for Candida albicans under both growing and nongrowing conditions. BMY-28864 expressed fungicidal activity only in the presence of Ca2+, and its activity was totally diminished when ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA), a Ca2+ chelator, was added to the test medium. The effectiveness of intravenously administered BMY-28864 in vivo was examined and compared with that of amphotericin B in mouse models of fungal infections. Both normal and cyclophosphamide-treated immunosuppressed mice infected with C. albicans, Cryptococcus neoformans, or Aspergillus fumigatus responded to therapy with BMY-28864 (50% protective doses of 17, 18, and 37 mg/kg of body weight in normal mice and of 32, 35, and 51 mg/kg in cyclophosphamide-treated mice, respectively). Lethal lung infections were also established with C. albicans or A. fumigatus in cyclophosphamide-treated mice. The 50% protective doses of BMY-28864 were 15 and 23 mg/kg per dose against C. albicans and A. fumigatus, respectively. The immunosuppression induced by intraperitoneal administration of 200 mg of cyclophosphamide per kg lasted for 5 days, and total recovery was observed by day 7.

Amphotericin B↗
PubMed1991

Inhibitory effects of copiamycin A, a macrocyclic lactone antibiotic, on gastric H+,K(+)-ATPase, acid secretion and ulcer formation.

When 17 macrocyclic lactone antibiotics were examined for their abilities to inhibit gastric H+,K(+)-ATPase, copiamycin A was found to have the strongest and relatively specific activity with IC50s of 15.7 micrograms/ml and greater than 100 micrograms/ml against the hog gastric H+,K(+)-ATPase and the dog kidney Na+,K(+)-ATPase, respectively. Furthermore, this antibiotic inhibited the histamine-induced gastric acid secretion in the isolated gastric mucosal membrane of guinea pigs and the gastric ulcer formation in pylorus-ligated rats.

Adenosine Triphosphatases↗
PubMed1991

Dynemicins O, P and Q: novel antibiotics related to dynemicin A isolation, characterization and biological activity.

New antibiotics, dynemicins O (3), P (4) and Q (5), were isolated from the culture broth of Micromonospora chersina M956-1, the dynemicin A (1)-producing strain. An ethyl acetate extract of a tank culture was roughly separated by a column of Diaion SP-800 and was further purified by combining a variety of column chromatographies to afford a few mg of compounds 3, 4 and 5. Their structures, analyzed from the spectral data, had a bridging phenylene group, a vic-diol and an oxo group in place of the respective 1,5-diyn-3-ene bridge, the epoxide ring and the carboxyl group in dynemicin A. Their biological activities were evaluated against bacteria and tumor cells.

Alkenes↗
PubMed1991

Dynemicins, new antibiotics with the 1,5-diyn-3-ene and anthraquinone subunit. I. Production, isolation and physico-chemical properties.

Dynemicin A, a novel antibiotic containing the bicyclo[7.3.1]-1,5-diyn-3-ene and 1,4,6-trihydroxyanthraquinone functionalities, was isolated from the culture broth of Micromonospora chersina sp. nov. M956-1. The antibiotic exhibited potent in vitro antibacterial and cytotoxic activity, and in in vivo, it cured mice from lethal Staphylococcus aureus infection and prolonged survival time of mice inoculated with murine tumors. Three satellite components, dynemicins L, M and N, were also isolated from the culture broth and chemically characterized.

Animals↗
PubMed1991

Dynemicins, new antibiotics with the 1,5-diyn-3-ene and anthraquinone subunit. II. Antitumor activity of dynemicin A and its triacetyl derivative.

Dynemicin A showed extremely potent in vitro cytotoxicity against a variety of murine and human tumor cells. In the experimental animal tumor models implanted ip with P388, L1210 leukemias and B16 melanoma cells, dynemicin A administered ip significantly prolonged life-span of tumor-bearing mice with the wide range of activity. This antibiotic administered iv was also active against iv implanted P388 and L1210 leukemias. In the macromolecule biosynthesis of B16 melanoma cells, dynemicin A inhibited DNA synthesis specifically. The triacetyl derivative exhibited similar in vitro and in vivo antitumor activities to those of the parent antibiotic.

Animals↗
PubMed1991

Melanostatin, a new melanin synthesis inhibitor. Production, isolation, chemical properties, structure and biological activity.

Melanostatin, a new antibiotic with melanin synthesis inhibitor activity, was isolated from the fermentation broth of Streptomyces clavifer No. N924-2. Its structure was determined by spectral analysis and degradation experiments. Melanostatin strongly inhibited melanin formation in Streptomyces bikiniensis NRRL B-1049 and B16 melanoma cells.

Chromatography, Thin Layer↗