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Biomedical subjects

Y Asada

Publications and source records attributed to Y Asada.

At least 253 records · Page 14Linked to original sources
PubMed1990

[An elderly case of small cell lung cancer showing complete response by oral administration of etoposide].

An 87-year-old female was admitted with left chest pain and dyspnea in January 1989. The chest X-ray film revealed complete atelectasis of the left lung. Bronchoscopic observation revealed a tumor which was bleeding easily at left main bronchus. Cytological findings of the bronchial aspirates showed small cell lung cancer. Because she was old and had some complications, she was difficult to treat by standard combination chemotherapy. Only etoposide at 150 mg/day was administered orally for 3 days (first course). After the first course the whole lung atelectasis improved; and after the second course (etoposide at 150 mg/day for 4 days) the tumor of the left main bronchus disappeared under endoscopic examination. Malignant cells were not detected in the bronchial aspirates and biopsy specimens. No severe side effect except for alopecia and mild gastrointestinal symptoms such as nausea and vomiting was noted. Myelosuppression was not evident. This case suggested that etoposide administered orally is useful in the treatment of small cell lung cancer especially in elderly patients with complications.

Administration, Oral↗
PubMed1989

Radiographic and microscopic evaluation of subperiosteally implanted blocks of hydroxylapatite-gelatin mixture in rabbits.

The efficacy of using gelatin as an adherent of particulate hydroxylapitite was studied by implanting preformed blocks of a hydroxylapatite-gelatin mixture subperiosteally on the buccal aspect of the mandible in rabbits. The rabbits were killed at 1, 2, 4, 12, and 24 weeks after implantation. After radiographic examination, excised specimens were decalcified and examined microscopically. The radiographic findings in the hydroxylapatite-gelatin group were essentially consistent with those of the hydroxylapatite group, except that in the hydroxylapatite group migration of particles was seen in some specimens. Microscopically the majority of the gelatin was unidentifiable at 1 week and there was no evidence of a rejection response. The degree of new bone formation and tissue response in hydroxylapatite-gelatin mixture group was essentially the same as in the hydroxylapatite group. The results indicate that gelatin is an excellent adherent for particulate hydroxylapatite, enabling easy handling and proper placement of the material with no inhibitory effect on new bone formation.

Animals↗
PubMed1989

Radiographic and microscopic evaluation of subperiosteally implanted blocks of hydrated and hardened alpha-tricalcium phosphate in rabbits.

Tissue response to preformed tricalcium phosphate (TCP) blocks prepared from alpha-tricalcium phosphate (alpha-TCP) powder by hydration and hardening at 80 degrees C was studied by implanting them subperiosteally on the buccal aspect of the mandible in rabbits. X-ray diffraction of the alpha-TCP powder showed a typical pattern of TCP, whereas a mixed pattern of TCP and hydroxylapatite was obtained after hydration and hardening. The radiographic findings at 4 weeks showed a tendency to bony union of the TCP block with the underlying bone. Microscopically, new bone that was being formed extensively from the underlying bone surface and filling the space between the block and bone at 4 weeks gradually changed into lamellar bone. There was no evidence of resorption of the TCP block throughout the experiment. The tissue response was essentially consistent with that to hydroxylapatite particles studied under similar conditions in our laboratory. It was concluded that the hydration and hardening of alpha-TCP powder may provide an implant block with a desirable contour that does not interfere with bone formation.

Animals↗
PubMed1989

Effects of progesterone and estradiol on aminopeptidase A (AAP) and leucine aminopeptidase (LAP) activities in the pregnancy serum and placenta of the rat.

We investigated the effects of estradiol and progesterone on placental aminopeptidase A and leucine aminopeptidase activities in pregnant rats. Estradiol (0.5, 1.0 and 2 mg/day) plus progesterone (5, 10 and 20 mg/day) was given for five days starting from the 16th day. Changes in both enzyme activities in the serum, placental cytosol and microsome caused by the steroids were analyzed. Aminopeptidase A activities in all three compartments and leucine aminopeptidase activities in the serum and cytosol were stimulated by estradiol (1.0 mg/day) plus progesterone (10 mg/day). Since we previously found that the placental aminopeptidases degrade peptide hormones, our present study suggests that steroids effect the metabolism of peptide hormones of fetal and/or maternal origin.

Aminopeptidases↗
PubMed1989

[A papillary-cystic neoplasm of the pancreas, a calcifying-inverted variant].

A calcifying-inverted variant of a papillary-cystic neoplasm (PCN) is reported, presenting presented the same histological and cellular features, and similar immunohistochemical characteristics and the ultrastructure of a papillary-cystic neoplasm of the pancreas (PCN) that usually afflicts younger women. It took the form of a partiality of a capsule, a common trait for a PCN, and proliferated on infiltrating the pancreatic parenchyma. The case involves a 51-year-old woman, whose PCN was detected by an abdominal X-ray that showed a calcified shadow in a health examination, though there was no palpable abdominal tumor. Usually, a PCN is detected by palpation tumor. Thus, the author demonstrates the existence of PCN variants, characterized by intrapancreatic infiltrating proliferation and an incomplete cyst formation or intratumoral calcified foci, and reports on variants of the usual PCN.

Calcinosis↗
PubMed1988

Experimental burn-induced changes in lipid peroxide levels, and activity of superoxide dismutase and glutathione peroxidase in skin lesions, serum, and liver of mice.

The lipid peroxide levels and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in skin lesions, liver, and serum of mice were measured from the 15th min to 6th day after burns were inflicted on their skin. The lipid peroxide levels in the skin lesions were increased at the 24th h and on the 3rd day after the burns were inflicted. However, the SOD activity did not increase but was significantly decreased from the 30th min to 24th h. GSH-Px activity was almost undetectable in both skin and serum. The lipid peroxide levels in the serum were significantly increased and SOD activity slightly increased at the 4th h. The lipid peroxide levels in the liver were elevated at the 4th h and on the 3rd day although a slight decrease was observed at the 8th h. SOD and GSH-Px activities in the liver increased from the 4th to 24th h. The present study illustrates the changes in both burn-induced lipid peroxides in each organ and the induction mechanisms of the activities of oxygen radical scavenging enzyme, SOD, and lipid peroxide processing enzyme, GSH-Px, which responded to oxygen stress.

Animals↗
PubMed1988

Vascular injuries induced by materials released from platelet-rich thrombus in vivo.

Polyethylene tubing was inserted into the ascending aorta of rabbits via the right common carotid artery and placed for one or four weeks continuously to induce vessel wall injury and thrombotic events, and then the direct non-injured segments from the descending thoracic and abdominal aorta were examined morphologically and for [3H]thymidine incorporation into endothelial cells and smooth muscle cells. The descending aortas of experimental rabbits showed endothelial damage and increased mitosis of endothelial cells. [3H]Thymidine incorporation into the intima and media was significantly increased in the experimental group. This experiment indicates that materials released from activated platelets and/or thrombi into the circulation can cause endothelial damage and smooth muscle cell proliferation at downstream and remote aortic segments.

Animals↗
PubMed1988

Disseminated necrotizing encephalopathy induced by methotrexate therapy alone.

This report describes the autopsy findings in a 62-year-old woman who died of pneumonia and disseminated necrotizing encephalopathy following intrathecal methotrexate (MTX) therapy for meningeal infiltration of lymphoma cells. Radiation therapy was not given. An interesting pathological finding was exudation of fibrin around the small vessels in the demyelinated foci, suggesting increased vascular permeability. This observation and analysis of previous reports of similar cases suggest that primary vascular injury, probably due to the direct effect of MTX, may be involved in the pathogenesis of MTX-related disseminated necrotizing encephalopathy.

Brain↗
PubMed1987

A rare case of Maffucci's syndrome combined with tuberculum sellae enchondroma, pituitary adenoma and thyroid adenoma.

Maffucci's syndrome is a rare, congenital mesodermal dysplasia combined with dyschondroplasia and haemangiomatosis, and there are only about 150 reported cases. This syndrome is often combined with other neoplasms. Our case was associated with goitre, enchondroma of the tuberculum sellae and pituitary adenoma; the latter brought about disturbance of vision. Including ours, four cases of Maffucci's syndrome associated with pituitary adenoma are found in the literature. In the case of Maffucci's syndrome, it is necessary to examine associated disease as well as associated pituitary adenoma and skull base enchondroma, similar to the correlation of von Recklinghausen's disease with acoustic neurinoma.

Adenoma↗
PubMed1986

Purification and characterization of yeast L-kynurenine aminotransferase with broad substrate specificity.

L-Kynurenine aminotransferase [L-kynurenine:2-oxoglutarate aminotransferase (cyclizing), EC 2.6.1.7] has been purified to homogeneity and crystallized from cell-free extracts of a yeast, Hansenula schneggii, grown in a medium containing L-tryptophan as an inducer. The enzyme has a molecular weight of about 100,000 and consists of two subunits identical in molecular weight (52,000). The enzyme exhibits absorption maxima at 280, 335, and 430 nm, and contains 2 mol of pyridoxal 5'-phosphate per mol of enzyme. The enzyme-bound pyridoxal 5'-phosphate shows negative circular dichroic extrema, in contrast with other pyridoxal 5'-phosphate acting on L-amino acids. In addition to L-kynurenine and alpha-ketoglutarate, which are the most preferred substrates, a large number of L-amino acids and alpha-keto acids can serve as substrates; the extremely broad substrate specificity is the most characteristic feature of this yeast enzyme. The enzyme activity is significantly affected by both carbonyl and sulfhydryl reagents. Certain dicarboxylic acids such as adipate and pimelate act as competitive inhibitors. Addition of various substrate amino acids to the culture medium results in the inductive formation of aminotransferases which are immunochemically indistinguishable from L-kynurenine aminotransferase.

Amino Acids↗
PubMed1986

Aerobic Hydrogen Accumulation by a Nitrogen-Fixing Cyanobacterium, Anabaena sp.

Hydrogen evolution by a nitrogen-fixing cyanobacterium, Anabaena sp. strain N-7363, was tested in order to develop a water biophotolysis system under aerobic conditions. A culture of the strain supplemented with carbon dioxide under an air atmosphere evolved hydrogen and oxygen gas, which reached final concentrations of 9.7 and 69.8%, respectively, after 12 days of incubation. Hydrogen uptake activity was not observed during incubation, and nitrogenase was thought to be the sole enzyme responsible for the hydrogen evolution.

Journal Article↗
PubMed1985

Immunohistochemistry of vascular lesion in thrombotic thrombocytopenic purpura, with special reference to factor VIII related antigen.

We collected 23 autopsied cases of thrombotic thrombocytopenic purpura (TTP) and examined them immunohistochemically and electronmicroscopically to elucidate the nature of thrombi and subendothelial deposits. The findings were compared with those of 10 cases of disseminated intravascular coagulation (DIC) and 3 cases of polyarteritis nodosa (PN). Intravascular thrombi and subendothelial hyaline deposits in TTP stained weakly for fibrinogen/fibrin by the PAP technique, while they stained strongly for factor VIII related antigen (FVIIIR: Ag). Electronmicroscopically, thrombi in TTP were composed of numerous, variably degranulated and altered platelets, and a small amount of amorphous materials. Thrombi in DIC were strongly positive for fibrinogen/fibrin, while they were weakly positive for FVIIIR:Ag. Electronmicroscopically they were composed of polymerized fibrin. Fibrinoid necrotic lesions in PN were strongly positive for fibrinogen/fibrin but negative for FVIII R:Ag. Based on these findings, we concluded that thrombi in TTP are essentially platelet thrombi and that subendothelial hyaline deposits may not be a result of increased vascular permeability but may be platelet thrombi incorporated into the arterial wall and covered with newly formed endothelial cells.

Adolescent↗