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Biomedical subjects

N Okazaki

Publications and source records attributed to N Okazaki.

At least 73 records · Page 4Linked to original sources
PubMed1992

Purification and characterization of an antibiotic substance produced from Rhizopus oligosporus IFO 8631.

We obtained a purified antibiotic protein from the submerged cultivation broth of Rhizopus oligosporus IFO 8631 by using CM-Cellulofine chromatography and HPLC. The antibiotic did not show a broad spectrum of activity, but it was very active against some of the Bacillus species, especially against Bacillus subtillis (B. natto) at a very low concentration (less than 1 ppm). It also showed activity against other gram-positive bacteria, including Staphylococcus aureus and Streptococcus cremoris. The purified antibiotic was a simple protein of about 5,500 in molecular weight, the amino acid component being characteristically high in cystine content. This high cystine content contributed to the stability of the antibiotic over a wide pH range and against strong heating (50% of the activity remained after boiling for 1 hr).

Amino Acids↗
PubMed1992

Radiotherapy for bone metastases of hepatocellular carcinoma.

Radiotherapeutic effects of 42 bone metastases in 26 hepatocellular carcinoma patients were retrospectively analyzed. Pain relief was observed in 79% of 37 bone metastases treated (29/37). Antitumor effects and improvement of paralysis were also observed in 88% (8/9) and 17% (1/6), respectively. The toxicities experienced were tolerable. Radiotherapy was an effective means of palliation in the treatment of hepatocellular carcinoma bone metastases.

Adult↗
PubMed1991

Spontaneous ovarian tumour in a medaka (Oryzias latipes).

Swelling of the abdomen was found in an adult female medaka (Oryzias latipes). Multiple tumour masses occupying most of the abdominal cavity were found at necropsy. Histologically, the tumour consisted of homogeneous round cells arranged in islands and occasional trabecular structures with thin capsules. Ova at various stages of maturation were seen in the periphery of the tumour mass. Metastasis was observed in the vicinity of the thyroid gland with accompanying infiltration by lymphocytic cells and also abdominal muscles. The tumour cells were characterized by a large ovoid nucleus with no aggregation of heterochromatin, occasional mitotic figures and prominent nucleoli. Examination by electron microscopy showed cells with scant cytoplasm but many ribosomes and a few other organelles. Annulate lamellae and dense cytoplasmic masses were also frequently observed. Based on the above features, the tumour was diagnosed as an ovarian dysgerminoma, the first reported case in a medaka.

Animals↗
PubMed1991

The ste4+ gene, essential for sexual differentiation of Schizosaccharomyces pombe, encodes a protein with a leucine zipper motif.

Ste4- mutants of Schizosaccharomyces pombe are unable to undergo both mating and meiosis. We have cloned the ste4+ gene and its cDNA. The gene encodes a 264 amino acid protein with a typical leucine zipper motif homologous with the jun family. However, unlike the jun family, this protein does not have a typical basic region that precedes the leucine zipper. The transcription of this gene absolutely depends on the ste11+ gene and increases several fold upon nitrogen starvation, a general signal for sexual differentiation. Whereas ste4+ is essential for mating and meiosis, its overexpression inhibits these processes.

Amino Acid Sequence↗
PubMed1991

A sensitive method for detecting the fermentation-inhibition antibody to Mycoplasma pneumoniae.

The fermentation-inhibition (FI) test for Mycoplasma pneumoniae was improved by using a combination of guinea pig complement and gamma globulin-depleted horse serum in place of unheated whole horse serum employed in the conventional assay system. As the test antigen for the new FI assay system, M. pneumoniae filtrated through a 3.0 microns membrane filter was used. Owing to the strong augmenting effect of guinea pig complement, the FI activity of rabbit immune serum was increased 32-fold in the new system compared with the conventional system. Furthermore, IgM antibody, which is barely detectable by the conventional system, could easily be titrated by the new system. With this sensitive method, rapid rise of FI titer was clearly demonstrable in most children with acute M. pneumoniae infections, and a prevalence of FI or growth-inhibitory antibody among healthy adults in Japan (82%) was revealed.

Adolescent↗
PubMed1991

Detection of hepatitis C virus infection by enzyme-linked immunosorbent assay system using core protein expressed in Escherichia coli.

Enzyme-linked immunosorbent assay of the core protein of hepatitis C virus (HCV) expressed in E. coli led to detection of the antibody against this virus in patients with chronic hepatitis. Some of the negative results obtained using a different viral protein became positive with this E. coli-expressed viral protein, and were also positive for the viral RNA. Thus, use of the core protein of HCV facilitates accurate detection of HCV infection.

Base Sequence↗
PubMed1991

Phase II study of continuous venous infusion of 5-fluorouracil in advanced pancreatic cancer.

Continuous venous infusion of 5-fluorouracil (5FU) was investigated in 18 patients with measureable advanced cancer of the pancreas. 5FU was given for 7 days in a dose of 500 mg/m2 by continuous venous infusion over a 24-hour period and then followed by a dose of 170 mg/m2 for more than 28 days. Ten patients had no change including 1 patient with minor response, and 4 patients had disease progression. Serum CA19-9 levels were measured serially after chemotherapy in 13 of 14 evaluable patients. In 3 of 10 patients who showed high levels before treatment, serum CA19-9 levels were significantly decreasing after treatment.

Aged↗
PubMed1991

Enhanced expression of CD2 antigen on lung T cells.

CD2 molecules not only function in the adhesion of T cells to other cell types but also in the activation of T cells via an alternative pathway. To investigate the possible roles of CD2 molecules in the activation and accumulation of lung T cells, using monoclonal antibodies and a flow cytometer we evaluated CD2 antigen expression on lung and blood lymphocytes in 10 normal subjects, 30 patients with pulmonary sarcoidosis, 7 patients with interstitial pneumonia associated with collagen vascular disease, 5 patients with farmer's lung disease, and 8 patients with Crohn's disease. The mean fluorescence intensity (MFI) of CD2 on lung T cells obtained by bronchoalveolar lavage (BAL) was significantly higher than that on blood T cells in all study groups except the control group. In patients with pulmonary sarcoidosis this enhancement of the expression of CD2 antigen was observed only on CD4+ T cells. Since ligands for CD2 are present on immunocompetent cells of other types in the local pulmonary milieu, these results suggest that increased expression of CD2 molecules could facilitate the communication and interaction of lung T cells with their environment in the lung and thereby possibly contribute to the local accumulation of T cells.

Adult↗
PubMed1991

Changes in mode of response to chemotherapy for hepatocellular carcinoma induced by transarterial embolization. A case report.

A 61-year-old man received systemic mitoxantrone chemotherapy following transarterial embolization of a large hepatocellular carcinoma with extensive intrahepatic, lung and bone metastases. His serum alpha-fetroprotein levels were 199,000 ng/ml prior to chemotherapy. He was given 10 mg mitoxantrone/m2 (14 mg/dose) intravenously every three weeks, and showed a rapid decrease in his serum levels of alpha-fetoprotein. There was almost complete resolution of the multiple bilateral metastatic lung nodules at five weeks and a marked decrease in the size of the intrahepatic metastatic nodules by seven weeks. The primary tumor, however, which had been previously treated by transarterial embolization, only underwent a 33% reduction in size according to WHO criteria. This occurred despite the disappearance, demonstrated by contrast enhanced computed tomography, of all viable tumor tissue. Ultrasonography also revealed only a minor regression, and could demonstrate no changes in the tumor echo pattern. The response pattern observed in this patient indicates the response to chemotherapy for hepatocellular carcinoma to be modified by prior transarterial embolization.

Carcinoma, Hepatocellular↗
PubMed1991

Accelerated tumor growth and changes in images concomitant with vascularization in a patient with hepatocellular carcinoma.

We examined serial changes of tumor images in a patient with hepatocellular carcinoma. The hepatocellular carcinoma was initially detected as a homogeneous low-echo area with unclear margins, which was not enhanced by contrast media on computed tomograms, and did not reveal any vascular abnormalities on hepatic angiography. About 11 months later, the tumor growth accelerated, with a parallel increase in serum alpha-fetoprotein levels, and the ultrasonographic features of the tumor changed from a homogeneous low-echo area to a mixed low- and high-echo area with a peripheral low-echo zone. Hepatic angiography revealed a hypervascular tumor at this time. The present case indicates that tumor growth and imaging patterns of hepatocellular carcinoma are closely related to vascularization of the tumor.

Carcinoma, Hepatocellular↗
PubMed1991

[The suppressive effects of smoking on antibody production in experimental hypersensitivity pneumonitis in rabbits].

Farmer's lung disease is one type of hypersensitivity pneumonitis (HP) in dairy farmers, and is usually caused by Micropolyspora faeni (Mf). It has been reported that the positive rate of precipitin antibody to Mf in smoking dairy farmers is one-eighth to one-half of that in nonsmoking dairy farmers. To clarify the mechanism of this phenomenon, by using an experimental HP model in rabbits, we investigated 1) the effects of short (5 weeks) and long (20 weeks)-term cigarette smoke exposure on the antibody formation, 2) the effects of 30 weeks of smoke exposure on the accessory cell function of alveolar macrophages (AM). Smoking exerted variable influences on antibody production, depending on the duration of smoke exposure, and we confirmed that long-term smoke exposure had suppressive effects. In addition AM from smoked rabbits suppressed lymphoproliferative response to autologous spleen cells. It was concluded that in this experimental HP, smoking affects the functions of both AM and lymphocytes, and that it suppresses antibody production as long as the smoke exposure continues.

Alveolitis, Extrinsic Allergic↗
PubMed1991

[A long-term follow-up case of sarcoidosis with fibrosis and silicotic nodules in the lung].

An autopsy case of a 70-year-old woman with sarcoidosis followed up for 16 years is reported. She was admitted for examination of bilateral hilar lymphadenopathy on chest X-ray film and uveitis in 1971. Sarcoid granuloma was revealed by Daniels lymph node biopsy. After steroid therapy, bilateral hilar lymphadenopathy and uveitis disappeared. However, small nodular shadows appeared in bilateral lower lung fields on chest X-ray film in 1973. Gradually small nodular shadows increased and reticular shadows appeared. In 1980, chest X-ray film revealed fibrotic change in the bilateral lung fields and giant bulla in the left upper lung field. She developed acute pneumonia and died of acute progression of chronic respiratory failure in 1987. Autopsy revealed sarcoid granulomas and honeycomb lesions in bilateral lungs and also silicotic nodules near the sarcoid granuloma in the upper lobes. This case suggests that inhaled mineral particles may play an important role in the development of pulmonary fibrosis in sarcoidosis.

Aged↗
PubMed1991

[Chemotherapy in cancers of the gallbladder and bile ducts].

Chemotherapy for cancers of the biliary tract remains underdeveloped, mainly because of their low incidence. There have been no well-designed chemotherapeutic trials based on a sufficient number of cases in this field. The summarized results from the literature and our experience indicate no standard regimen for chemotherapy of the biliary tract cancers. To improve chemotherapy for these cancers, the development of new active anticancer agents is essential. And, for clinical trials of chemotherapy for this relatively rare cancer, a cooperative group study is considered to be necessary to obtain meaningful results within a reasonable period.

Adenocarcinoma↗
PubMed1990

High-frequency transformation method and library transducing vectors for cloning mammalian cDNAs by trans-complementation of Schizosaccharomyces pombe.

We describe a highly efficient alkali cation method and library transducing vectors for cloning mammalian cDNAs by trans-complementation of fission yeast Schizosaccharomyces pombe mutants. cDNA libraries constructed with the pcD or pcD2 vector are transduced into yeast by cotransfection with a linearized vector, which allows an enhanced homologous recombination between the yeast vector and the library plasmid leading to the efficient formation of concatemers containing pcD molecules. The transformation frequencies obtained by the method are 10(6) colonies per 10(8) cells transfected with 2 micrograms of library and 1 microgram of vector, 50-60% of which contain pcD molecules. The high-efficiency alkali cation method circumvents many of the shortcomings of the spheroplast method generally used for Schiz. pombe transfection. The vectors are maximized for the efficiency of library transduction and minimized for the rearrangements of pcD molecules during propagation in yeast. This system allows rapid screening of multi-million cDNA clone libraries for rare cDNAs in a routine scale of experiments. Using this system, various mammalian cDNAs that are extremely difficult, time-consuming, or unclonable to clone by other methods have been cloned.

Animals↗
PubMed1990

Malignant transformation of adenomatous hyperplasia to hepatocellular carcinoma.

To clarify the course of adenomatous hyperplasia (AH) of the liver, 17 patients with 20 biopsy-proven AH nodules were followed clinically for 1-5 years. At the initial biopsy the mean nodular diameter was 10 (SD 4) mm and the relative cellularity [( mean cellularity of AH divided by mean parenchymal cellularity] x 100) 141 (27). The criteria for diagnosis of malignant transformation of AH were both a doubling of nodular volume and changes on imaging. Between 6 and 50 months after biopsy, 9 of the 18 nodules which could still be accurately identified met the criteria for transformation; histological proof of hepatocellular carcinoma (HCC) was obtained later for 7 of these 9 nodules. The product of diameter and cellularity (transformation index) was the strongest predictor of the time to transformation. 9 AH nodules did not undergo transformation--7 did not meet one or both criteria and 2 became undetectable by imaging. Because of the high risk of malignant transformation, it can be concluded that AH is an absolute precursor of HCC. It should therefore be treated as a potential malignant disorder.

Adenocarcinoma↗