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Biomedical subjects

M Asada

Publications and source records attributed to M Asada.

At least 163 records · Page 9Linked to original sources
PubMed1984

Mechanism of phorbol myristate acetate-induced lymphotoxin production by a human T cell hybridoma.

Various hydroxyl radical scavengers markedly inhibited phorbol myristate acetate (PMA)-induced lymphotoxin (LT) production by a human T cell hybridoma, AC5-8. Among those we tested, tetramethylurea (TMU) was the most potent scavenger, and it was revealed that TMU must be added before 2 h have elapsed after PMA addition in order for LT production to be inhibited. In concordance with this fact, soluble NADPH dependent O2- forming enzyme(s) were activated several fold by PMA. PMA also induced DNA strand breaks, a process markedly inhibited by TMU. As expected, ADP-ribosyl transferase (ADPRT), which is well known to require DNA strand breaks for its enzymatic activity, was activated by PMA treatment. In addition, specific inhibitors for ADPRT, namely 3-amino-benzamide and nicotinamide, inhibited PMA-induced LT production. Taken together, these three successive events, activation of soluble NADPH dependent O2- forming enzyme(s), DNA strand breaks and activation of ADPRT, may be required for PMA-induced LT production by AC5-8.

Cell Line↗
PubMed1984

[Spontaneous dissecting aneurysm of the cervical internal carotid artery. Report of 2 cases and review of literature].

Two cases of the spontaneous dissecting aneurysm (SDA) of the cervical carotid artery (ICA) were reported. Case 1: A 36 years old man was admitted with a sudden onset of right hemiparesis, aphasia and a one-week history of headache and neck pain. Serological examinations were normal. Angiography showed a severe stenosis with two intimal flaps of the left cervical ICA. Four weeks later, left STA-MCA anastomosis was performed. After six weeks from the onset, re-angiography showed the resolution of the left cervical ICA stenosis. Case 2: A 26 years old man experienced the transient monoocular blindness a week before admission. He was admitted with a sudden onset of right hemiparesis and aphasia. Serological examinations were normal. Angiography showed a postsinus tapering occlusion of the left cervical ICA. Four weeks later, left STA-MCA anastmosis was performed. After the operation, left hemiparesis improved remarkably. After two weeks from the operation, re-angiography showed the complete resolution of the left cervical ICA stenosis. As the differential diagnoses, spasm, arteritis, embolism and thrombosis with atherosclerosis were listed. But from the reason reported, we diagnosed the two cases as the resolution of the SDA of the ICA. From the previous literature, 129 cases of SDA of the ICA were reviewed and discussed about the symptom, angiographic findings and treatment. Some specific findings (high frequency of resolution, 87%, etc.) were found. SDA of the ICA occurs in the non-atherosclerotic age and causes the ischemic brain damage. SDA of the ICA should be paid more attention and will probably be identified more frequently.

Adult↗
PubMed1984

[2 cases of renal cell carcinoma on long-term hemodialysis].

Two cases of renal cell carcinoma on maintenance dialysis for chronic renal insufficiency are reported. The first case, a 40-year-old man, complained of hematuria after 9.3 years of dialysis. Nephrectomy was done and small renal cell carcinoma with acquired cystic disease of the kidney were observed. The second case, a 48-year-old man, was found to have renal cell carcinoma after 2.5 years of dialysis by means of routine examination without any symptoms. The kidney showed carcinoma with small cystic areas and four adenomas. Usefulness of routine examination with echogram is stressed for management of hemodialysis.

Adult↗
PubMed1983

Human T-cell hybridomas producing lymphokines. II. Enhancement of lymphotoxin secretion from human T-cell hybridomas by phorbol myristate acetate.

Human lymphotoxin (LT)-producing T-cell hybridomas were constructed by fusing concanavalin A-activated human peripheral blood lymphocytes with emetine-actinomycin D-pretreated human acute lymphatic leukemia cells. LT secretion from these hybridomas was considerably enhanced by stimulation with phorbol-12-myristate-13-acetate (PMA) and concanavalin A or PMA alone. A study using cloned hybrid lines revealed that PMA/Con A acted directly on the LT-producing clones. Furthermore, PMA/Con A stimulated A-B9-24, one of the cloned hybridomas, and secreted fourfold larger amounts of LT under serum-free conditions than under serum-containing conditions. However, MIF/MAF and LT-producing cloned hybrid line E10-20 secreted rather decreased amounts of MIF/MAF when stimulated with PMA, while the LT secretion from the same hybridoma was enhanced with PMA.

Clone Cells↗
PubMed1983

Human T-cell hybridomas producing migration inhibitory factor and macrophage activating factors.

Studies were carried out to determine the heterogeneity of factors that affect macrophage functions using human hybridomas constructed by fusing PHA-activated human peripheral blood lymphocytes with emetine-actinomycin D-pretreated cloned human acute lymphatic leukemia cells (CEM). Three assay systems were used to investigate the activity of the macrophage migration inhibitory factor and of the macrophage activation factors for glucose consumption (MAF-G) and for O2- formation. In the culture supernatant of hybridomas and other cells, various combinations of these activities were detected. The results indicate that at least three molecules are concerned in each of these activities.

Animals↗
PubMed1982

Human T cell hybridomas producing lymphokines. I. Establishment and characterization of human T cell hybridomas producing lymphotoxin and migration inhibitory factor.

Stable human T cell hybridomas were produced by cell fusion between PHA-activated human peripheral blood lymphocytes and human acute lymphatic leukemia cells of a CEM cell line whose proliferation had been inhibited by treatment with an irreversible protein synthesis inhibitor (emetine) and an irreversible RNA synthesis inhibitor (actinomycin D). Two hybrid cell lines (E10, F8) thus produced expressed OKT3-reactive antigen, HLA-A1 and -B8 antigens derived from CEM cells, and HLA-A2 antigen derived from PBL, and they have 10 more chromosomes than CEM cells. Furthermore, these cell lines continuously secreted lymphotoxin over 3 mo. E10 was found to produce MIF in addition to lymphotoxin. Cloning of E10 and the relationship between the functions and surface phenotypes of E10 sublines were examined. Lymphotoxin-producing hybrids (E10-15 and E10-37) express more OKT8-reactive antigen than OKT4-reactive antigen, while lymphotoxin and MIF-producing hybrids (E10-25, E10-42, and E10-43) express more OKT4-reactive antigen than OKT8-reactive antigen.

Antibodies, Monoclonal↗
PubMed1981

Differentiation of melanomas occurring in platyfish-swordtail hybrids of different ages: an ultrastructural study.

The degree of differentiation of two types of hereditary melanomas of interspecific hybrids between the spotted variety of the platyfish (Xiphophorus maculatus) and the swordtail (Xiphophorus helleri) was examined electron microscopically. Melanomas of the fry consisted mainly of pigmented cells containing intermediately matured melanosomes and few other cytoplasmic structures. Melanomas of the adult consisted of lightly pigmented cells having a small number of immature melanosomes; numerous polysomes; well-developed, rough-surfaced endoplasmic reticulum (RER) and Golgi systems; and irregularly shaped nuclei. Thus the fry and adult melanomas appear to represent relatively well- and poorly differentiated states of fish melanophores, respectively. Amelanotic melanomas in the adult melanotic F1 generation were also characterized. Virus-like particle were often found in the nuclei of both melanotic and amelanotic melanoma cells in the adult fish.

Age Factors↗
PubMed1981

Regulation of polar morphogenesis in Caulobacter crescentus.

Deoxyribonucleic acid (DNA) phage phi CbK-resistant nonmotile mutants of Caulobacter crescentus CB15 were examined for their formation of polar surface structures (a stalk, a single flagellum, pili, and DNA phage receptors). These mutants were devoid of pili and DNA phage receptors and simultaneously defective either in both stalk formation and flagellar activity (stalk-defective type) or in the formation of normal flagella (flagella-defective type). DNA phage phi Cr30-mediated transductions revealed that stalk-defective mutants were of a single genetic type, whereas flagella-defective mutants were grouped into two different genetic types, I and II. To investigate how membrane proteins change in the above morphology mutants, cell envelopes pulse-labeled with L-[35S]methionine were analyzed by two-dimensional gel electrophoresis. No gross change of membrane proteins was observed in the stalk-defective mutant CB15 pdr-803, except a 49,000-molecular-weight (49K) protein which was found reduced. However, a 27K, two 28.5K, and a 70.5K protein were missing from the membrane of the flagella-defective type I mutant CB15 pdr-813. These proteins are most likely to be flagella-related protein, flagellins A and B, and hook protein, respectively. In another flagella-defective type II mutant, CB15 pdr-816, the 27K and two 28.5K proteins were similarly absent but the 70.5K protein was consistently present in the membrane. The synthesis of flagellin was next assayed radioimmunologically in the above 35S-labeled mutants. Stalk-defective CB15 pdr-803 synthesized flagellin normally, compared to the wild-type strain. Flagellins A (26K) and B (28K) formed multiple spots in isoelectric focusing. A 29K protein was also detected in the flagellin-specific radioactivity from the cytoplasm. Flagella-defective type I CB15 pdr-813 synthesized flagellin only at a basal level. Thus transcription or translation of flagellin appeared to be repressed in this mutant. Another flagella-defective type II strain, CB15 pdr-816, however, synthesized flagellin at an apparently enhanced rate compared with the wild type. Flagellin synthesized in CB15 pdr-816 was flagellin A and a smaller 22K flagellin. Flagellin B was not synthesized in the mutant. It then follows that flagellin B is not a precursor of flagellin A and the 22K flagellin. Flagella-defective type II CB15 pdr-816, without flagellin B, formed a stub structure with a hook attached to one end instead of normal flagella. In the wild-type membrane, flagellin B was the major flagellin, whereas flagellin A was major in the cytoplasm and the flagellar filament. It is suggested from these results that flagellin B is important in the assembly of normal flagella.

Bacteria↗
PubMed1981

[Fetal growth assessment by the real-time ultrasono-tomography (author's transl)].

This paper is concerned with the methods and results of fetal growth assessment by using the real-time ultrasono-tomography under our newly systematized flow of the fetal management. The following results were obtained. 1) At early stage of pregnancy gestational age of the fetus may be corrected more precisely with the measurement of fetal crown-rump length (CRL) than diameter of amniotic space. 2) The correlation coefficient between gestational days by BBT base and CRL was 0.990 and standard deviation was +/- 2.3 mm. The error of estimated gestational days was +/- 3 days. 3) With one parameter such as the biparietal diameter (BPD), or the fetal abdominal circumference (FAC), it seems to be difficult to find out abnormal fetal growth from the normal growth at the last stage of pregnancy. 4) The discriminant function [Z = 0.6012 X (BPD) + 3 . 100 X (FAC) - 45.204] was obtained within seven days of delivery in order to find immature and mature neonates. With this equation, the probability for correct diagnosis was 90.4%, and 9 in 10 cases of IUGR were predicted. 5) Using four parameters (BPD, FAC, Gestational age, Uterine length), the predicted birth weights was computed. The correlation coefficient between the predicted birth weights and the actual birth weights was 0.852 and 1 S.D. was +/- 281 gram.

Analysis of Variance↗
PubMed1979

Dynamics of cerebrospinal fluid circulation evaluated by metrizamide CT cisternography.

Cerebrospinal fluid (CSF) circulation has been analyzed by metrizamide computed tomography (CT) cisternography in 46 patients. Included were 7 patients without any clinical evidence of impaired CSF circulation, and 39 with hydrocephalus due to various causes. CT cisternography delineated the anatomical structures of the CSF pathways clearly and accurately and enabled us to analyze ventricular filling in a quantitative manner. As a result, a new, more precise CT cisternographic classification of the CSF flow patterns has been established. On the basis of the presence of ventricular reflux and stasis, extent of ventricular filling, and convexity flow of metrizamide, seven groups of flow patterns have been defined.

Adult↗
PubMed1979

Postnatal changes in the distribution of lipid droplets within the liver lobule of the mouse.

The changes in the distribution of lipid droplets in the liver lobule were studied during the postnatal development of the mouse. At birth, and 1 day after birth, lipid droplets were evenly distributed throughout the lobule. A slightly uneven distribution of the droplets, more in centrilobular areas, appeared 2 days after birth. After this the difference in the number of droplets between the cells of the centrilobular and periportal areas became progressively more marked reaching a maximum by 17 days of age, and then decreasing to the adult level between 21 and 24 days. Thus, heterogeneity among hepatocytes with respect to lipid content is not present in newborn mice but develops gradually during the postnatal development.

Aging↗