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Biomedical subjects

S Okubo

Publications and source records attributed to S Okubo.

At least 217 records · Page 12Linked to original sources
PubMed1983

Recurrent pulmonary embolism.

Five cases with recurrent pulmonary embolism (RPE), all having severe chronic cor pulmonale due to marked pulmonary hypertension, were reported. None of them had a history of thrombophlebitis of the legs. Dyspnea was the common symptom and signs of pulmonary hypertension were usual. Focal oligemia, cardiomegaly and plump pulmonary arteries on chest X-ray films, right axis deviation, clockwise rotation, ST-segment depression and T-wave inversion on electrocardiograms, and dilatations of the pulmonary arterial trunk, the right ventricle and the right atrium, and the posterior displacement of a small, compressed left ventricle on echocardiograms were the common findings. Gas exchange abnormalities were severe and they were considered the characteristic findings of this disease. Multiple perfusion defects were observed by a lung scan in all cases. Marked pulmonary hypertension with low cardiac output was the usual feature of RPE. Actual cutoffs or filling defects were demonstrated on a pulmonary angiogram. Deep vein of the legs were all intact and no thrombi were found. Pulmonary embolectomy was performed on one case. The importance of early diagnosis and early treatment of acute pulmonary embolism was emphasized for preventing the progress of this debilitating disease.

Acute Disease↗
PubMed1983

[Usefulness of dynamic computed tomography in the diagnosis of thoracic aortic aneurysms].

Five patients with thoracic aortic aneurysms, two saccular and three dissecting aneurysms, were examined by dynamic computed tomographic (CT) scanning. A Siemens Somatom 2 was employed. Dynamic scanning is the method by which plural serial images can be obtained in single operation. We used three serial images in a 5-second scan following a 3-second interval. After rapid manual injection of 30 ml of 76% megluminc amidotrizoate sodium into the right antecubital vein, scans of 4 mm section were performed three times and subsequently conventional scans four times. Serial changes in the same section and changes in the CT number against time in regions of interest in the image were investigated. Saccular aneurysms was difficult to distinguish from mediastinal tumors on the plain chest X-ray films. However, it was confirmed by the dynamic CT scanning demonstrating free communication between the aorta and the abnormal lumen, because the latter was filled with contrast medium, and the time of appearance, and the peak and washout of a contrast medium were almost the same between two lumens. In dissecting aneurysms, it was able to recognize both the false and true lumens as double channels in the aorta. We observed the different mode of dissection between the ascending and descending aorta in one case, and observed the twisting of an intimal flap in variable parts of the aorta in another case. Furthermore, it was possible to confirm the difference of blood flow pattern between the false and true lumens by dynamic CT. Because CT has a high quality image resolution, and especially, dynamic CT provides the serial changes in the same section after injection of contrast medium, both CT and dynamic CT are useful non-invasive imaging techniques for evaluating thoracic aortic aneurysms.

Adult↗
PubMed1983

[Hypereosinophilic syndrome associated with giant negative T waves and left precordial high voltage. Echocardiographic and tomographic findings of a case].

We reported a case of hypereosinophilic syndrome with an apical thrombus obstructing left ventricular cavity near the apex and apical hypertrophy of the left ventricle demonstrated by echocardiography and computed tomography. Abnormal laboratory findings included a white blood cell count of 22,800/mm3 with 64 per cent of eosinophils, high serum IgE level, and eosinophilic abscess formation in the lymph node specimen. The electrocardiogram showed left precordial high voltage and giant negative T waves in leads V4-5. Two-dimensional echocardiograms revealed an abnormal mass obstructing the left ventricular cavity. Computed tomography demonstrated marked apical hypertrophy of the left ventricle and a filing defect of 24 X 31 mm, which attached to the interventricular septum. Because of the lack of its movement on echocardiograms and significant differences in CT numbers from various portions of the myocardium, the abnormal mass in the left ventricle was considered to be a thrombus. In this case, both echocardiography and computed tomography were very useful to understand structural relationship among the thrombus, interventricular septum and surrounding left ventricular walls, and to assess myocardial thickness of the apex. In addition, it is of particular interest that hypereosinophilic syndrome was associated with marked apical hypertrophy of the left ventricle.

Echocardiography↗
PubMed1983

[Diagnosis of left atrial masses by computed tomography: with special reference to the differentiation between mural thrombi and myxomas].

Computed tomographic features of left atrial mural thrombi were compared with those of left atrial myxomas using a third generation system. In seven of 23 patients with mitral valvular disease, computed tomography (CT) demonstrated a total of 12 left atrial mural thrombi. There was calcification in about one-third of the thrombi and marked calcification of the mitral valve in all the seven cases. Mean CT value of the 12 thrombi ranged from +17.5 to +89.8 Hounsfield units (HU) (average +44.5 HU), and in only one it was below +20 HU. All thrombi appeared to be heterogeneous and irregular in shape such as elliptic, triangular or flat on cross-sectional tomogram. In addition, reconstructed coronal and sagittal imagings from serial CT images were very useful for localizing the calcification in the thrombi and determining the site of the attachment of the thrombi to the atrial wall. On the other hand, calcification of the tumor or mitral valve was not detected in two patients with left atrial myxomas by CT. The mean CT value of myxoma was averaged +30.2 HU, which was lower than that of thrombi. Both myxomas were ovoid in shape and appeared to be homogeneous in CT images. ECG gated CT revealed pendular movement of the tumor which prolapsed through the mitral orifice into the left ventricular inflow tract during diastole and backed into the left atrium during systole, although it was slightly difficult to detect the site of the attachment of the tumor. In conclusion, we should evaluate appearances, calcification of the mitral valve, mean CT value, shape and movement in the computed tomographic diagnosis of left atrial masses. In consideration of these characteristic findings, differentiation between mural thrombi and myxomas could be made.

Adult↗
PubMed1983

[Clinical and experimental studies on DIC found in carcinoma; correlation between anti-cancer drug administration and endotoxemia].

The purpose of this study was to detect possible factors related to the occurrence of DIC in carcinoma patients. I) We studied 20 carcinoma cases accompanied with DIC. Results; The carcinomas most frequently accompanied with DIC were cancers of the biliary system, gastric, hepatic and pancreatic cancer, especially those with distant metastases. Pneumonia, UTI and biliary tract infections seemed to be the most important triggers of DIC. No significant relationship was found between anti-cancer chemotherapy and the DIC incidence. Endotoxemia was more frequently detected in patients having received anti-cancer drugs than in those who not. II) The effects of anti-cancer chemotherapy on the incidence of endotoxemia was examined in rats. A higher incidence of endotoxemia was noted in the groups treated with high doses of 5-FU or Cyclophosphamide. The incidence of endotoxemia seemed to run parallel with the incidence of diarrhea and of weight loss in each animal group.

Animals↗
PubMed1983

[Coenzyme Q10 in cancer chemotherapy--experimental studies on augmentation of the effects of masked compounds, especially in the combined chemotherapy with immunopotentiators].

Immunopotentiators may mitigate the depression of immunological function caused by the cancer itself or by chemotherapeutics. However, it has been found that these immunopotentiators reduce the metabolic activity of the host against drugs, including "masked" chemotherapeutics, which might be activated by metabolization in the body. Reported here is the result of serial experiments carried out on the activation of cyclophosphamide (CPM) in tumor-bearing animals, pretreated with phenobarbital, a drug-metabolizing enzyme inducer, and coenzyme Q10, a physiological activator of the electron transfer system in mitochondrias, in combination with immunopotentiators. Female Donryu rats (120 g body weight) implanted with Yoshida Sarcoma cells (YS) (2.5 X 10(6) i.p.) were treated with CPM (160 mg/kg X 1 i.p.), 84 hrs after implantation; the levels of the normustard-like substances (active metabolites of CPM) were serially measured. Some of the animals were also treated with PSK (125 mg/kg X 5 i.p.), a proteinpolysaccharide immunopotentiator obtained from mycelia of the Coriolus vesicolor, or with OK-432 (10 KE/kg X 5 i.m.), a streptococcal immunopotentiator. The results obtained were as follows: The blood levels of the normustard-like substances were lowered, i.e. the CPM activation was depressed in the YS-bearing rats and the depression was markedly intensified by PSK or OK-432 administration. Phenobarbital (40 mg/kg X 3 i.p.) or coenzyme Q10 (5 mg/rat X 5 i.p.) administration could mitigate the depression of the blood levels caused by the immunopotentiators, and the combination of phenobarbital with coenzyme Q10 could recover the blood levels up to those of the YS-bearing control rats, or even higher. YS-implanted (i.p.) rats treated with CPM+ immunopotentiators+coenzyme Q10 survived longer than those treated with CPM+immunopotentiators. These findings suggest the usefulness of coenzyme Q10 for the enhancement of cancer immunochemotherapy using masked compounds combined with immunopotentiators; all the more so, because coenzyme Q10 has also an immuno-stimulating effect, moreover, it presents almost no side effects in clinical application.

Animals↗
PubMed1981

Mutagenic effects of nitrogen dioxide combined with methylurea and ethylurea in Drosophila melanogaster.

The standard sex-linked recessive lethal test was used to test whether NO2 induces lethal mutations in male germ cells of Drosophila in the presence or absence of alkylureas. Methylurea, ethylurea and NO2 alone did not enhance the mutation frequency significantly. However, highly significant enhancement in the mutation frequency was observed when adult flies were exposed to NO2 (150--280 ppm) for 3 h after ingestion of methylurea (0.1 M) or ethylurea (0.1 M) for 2 days. Oral administration of ethylnitrosourea and also of methylurea or ethylurea that had been exposed to NO2 in vitro were more effective in increasing the mutation frequency than methylurea or ethylurea combined in vivo with NO2. These results suggest that ingested alkylurea is converted in vivo by inhaled NO2 to highly mutagenic nitrosoalkylurea and/or other mutagens. No significant enhancement of the mutation frequency was observed when flies were fed on methylurea solution after they had been exposed to NO2.

Animals↗
PubMed1981

Gilvocarcins, new antitumor antibiotics. 3. Antitumor activity.

Gilvocarcin V, isolated rom a Streptomyces culture showed activity against experimental tumors such as sarcoma 180, Ehrlich carcinoma, Meth 1 fibrosarcoma, MH134 hepatoma and lymphocytic leukemia P388. In particular, 40% of treated mice survived for 60 days, after intraperitoneal administration of gilvocarcin V to mice bearing Ehrlich ascites carcinoma. But it was marginally active against B16 melanoma and did not produce prolongation of lifespan of mice bearing Lewis lung carcinoma.

Aminoglycosides↗
PubMed1980

Inverted terminal repeat sequence in the macronuclear DNA of Stylonychia pustulata.

The structure of macronuclear DNA of a hypotrichous ciliate, Stylonychia pustulata, was examined by both electron microscopy and nucleotide sequence analysis. The DNA in the macronucleus consists of small linear molecules with average length of about 3400 base pairs (bp). Most, if not all, of these DNA molecules have identical inverted terminal repeat sequence of 20 nucleotide residues. This sequence is 5'-CCCCAAAACCCC-AAAACCCC.

Animals↗
PubMed1980

Studies on antitumor activity of prumycin. II. Studies on distribution and excretion of prumycin.

Tissue distribution, excretion and metabolism of prumycin in normal mice and rats were studied by microbiological assay. Following the injection of prumycin into mice, high activity was detected and continued for 24 hours in the kidney, and the activity was also high in the skin, uterus, bone, liver, lung and stomach in this order. But concentration in the brain, heart, spleen and testis were too low to detect even 5 minutes after the injection. Prumycin was not inactivated by a variety of tissue homogenates in vitro. Therefore, inability to detect activity of prumycin in the spleen and testis appears to result from poor distribution rather than inactivation by these organs. About 70% of injected prumycin was excreted into rat urine in 24 hours but it was not detectable in feces. When prumycin was injected intravenously into dogs at the dose over 10 mg/kg, vomiting was observed in all animals, and LD50 was about 50 mg/kg.

Amino Sugars↗
PubMed1980

Studies on antitumor activity of prumycin. III. Mode of action of prumycin on HeLa S-3 cells.

The mode of action of prumycin was investigated using synchronized and asynchronous cultured HeLa S-3 cells. Prumycin inhibited significantly the growth of HeLa S-3 cells at the concentration over 5 mcg/ml. DNA synthesis as well as protein synthesis was strongly inhibited at the concentration of 10 mcg/ml of prumycin, but RNA synthesis was not inhibited by the same concentration. Prumycin did not block the transition of the cells from M phase to G1 phase, however, G2 phase cells were blocked clearly by this antibiotic.

Amino Sugars↗
PubMed1980

Studies on antitumor activity of prumycin. IV. Effect of prumycin on mouse immune system.

The effect of prumycin on the mouse immune system was studied. Prumycin at a dose of 75 mg/kg (1/2LD50) showed essentially no suppression of hemolytic plaque forming cells (PFC) against sheep red blood cells (SRBC) when it was administered on day 0, 1 or 2. However, a weak suppression was observed by administration of prumycin on day 3. Also a remarkable suppression of PFC was demonstrated when mouse spleen cells were pre-incubated with prumycin at the concentration over 62.5 mg/kg in vitro. The delayed-type hypersensitivity reaction against SRBC was remarkably suppressed by cyclophosphamide, but it was not much by prumycin, except by administration on the day of elicitation. Prumycin of a high concentration inhibited an uptake of 3H-thymidine by mouse spleen lymphocytes incubated with or without phytohemagglutinin, but that of a low concentration, 1.9 approximately 0.03 mcg/ml, slightly increased the blastogenic stimulation of lymphocytes.

Amino Sugars↗