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Biomedical subjects

R Yamada

Publications and source records attributed to R Yamada.

At least 217 records · Page 12Linked to original sources
PubMed1989

[An early stage case of pulmonary lymphangiomyomatosis].

A 35-year-old unmarried woman was admitted to our hospital because of right pneumothorax. Pulmonary lymphangiomyomatosis was suspected from CT and transbronchial lung biopsy findings. The diagnosis was confirmed histologically by open lung biopsy. As her biopsy specimen showed positive findings for both estrogen and progesterone receptor, tamoxifen administration was started. The CT revealed multiple cystic lesions (5-10 mm in diameter) but otherwise normal vascular structures and normal lung density. The plain chest radiograph showed no abnormalities. CT is very useful for the early detection of pulmonary lymphangiomyomatosis.

Adult↗
PubMed1988

Presence of D-aspartate oxidase in rat liver and mouse tissues.

Rat liver D-aspartate oxidase activity, which had been reported to be undetectable, was found to be well detectable in dialyzed liver homogenate. The requirements of the enzyme for activity and its sensitivity to inhibitors were identical with the known properties of the enzyme from other sources. We also demonstrated for the first time the presence of the enzyme activity in mouse tissues and some other rat tissues using dialyzed tissue homogenates.

Amino Acid Oxidoreductases↗
PubMed1988

Immunohistochemical study of chromogranin in 100 cases of pheochromocytoma, carotid body tumour, medullary thyroid carcinoma and carcinoid tumour.

Neuroendocrine cells have histologically common features represented by argyrophilic cytoplasm containing neuroendocrine granules. Neuroendocrine granules are composed of various kinds of peptide hormones, amines, carrier proteins and ATP. Although various kinds of peptide hormones have been detected in neuroendocrine tumours, a peptide hormone has not been required as a standard marker for these tumours. Chromogranin is a purified protein which binds catecholamines specifically and is recognized as a carrier protein. We carried out an immunohistochemical study of chromogranin immunoreactivity in 100 neuroendocrine tumours including pheochromocytomas, carotid body tumours, medullary thyroid carcinomas and carcinoid tumours. Marked immunoreactivity was observed in 85% of carcinoid tumours and 100% of the other tumour types. A non-functioning paraganglioma and a malignant carcinoid tumour without any other detectable marker also showed strong immunoreactivity to chromogranin. Chromogranin immunoreactivity is a useful tool for neuroendocrine tumours.

Adrenal Gland Neoplasms↗
PubMed1988

Pulmonary hypertension associated with portal hypertension in childhood. Case report of a 6-year-old child and review of the literature.

Pulmonary hypertension is a rare complication of portal hypertension. Reports of childhood cases especially rare. This report describes an autopsy case of a 6-year-old boy with congenital biliary atresia followed by liver cirrhosis in whom severe hypertensive pulmonary arterial changes, including medial hypertrophy, intimal fibrosis and plexiform lesions were demonstrated. Fresh and organizing fibrin-platelet thrombi as well as probable organized thrombi with recanalization were occasionally found in the pulmonary vasculature, but it was thought that they had probably been formed locally as a late complication rather than being of thromboembolic origin. Retrospectively, the chest roentgenograms had revealed abnormalities suggestive of pulmonary hypertension since infancy, but the patient showed no apparent symptoms of it during life. Previously reported childhood cases of pulmonary hypertension associated with portal hypertension were briefly reviewed. Although the mechanism is presently not known, it is suggested that patients with portal hypertension, even in early childhood, are at risk of developing this unusual complication.

Biliary Atresia↗
PubMed1988

Purification and characterization of human placental aminopeptidase A.

Human placental aminopeptidase A (AAP) was purified 3,900-fold from human placenta and characterized. The enzyme was solubilized from membrane fractions with Triton X-100, then subjected to trypsin digestion, zinc sulfate fractionation, chromatographies with DE-52, Sephacryl S-300, and hydroxylapatite, affinity chromatography with Bestatin-Sepharose 4B, and finally immunoaffinity chromatography with the antibody against microsomal leucine aminopeptidase (LAP). Aminopeptidase A was completely separated from leucine aminopeptidase by the immunoaffinity chromatography. The apparent relative molecular mass (Mr) of the enzyme was estimated to be 280,000 by gel filtration. The purified enzyme was most active at pH 7.1 with L-aspartyl-beta-naphthylamide (L-Asp-NA) as substrate; the Km value for this substrate was 4.0 mmol/l in the presence of Ca2+. Human placental aminopeptidase A was markedly activated by alkaline earth metals (Ca2+, Sr2+, Ba2+), but strongly inhibited by metal chelating agents such as EDTA and o-phenanthroline. The highest activity was observed with L-glutamyl-beta-naphthylamide, while only minimal hydrolysis was found with some neutral and basic amino acid beta-naphthylamides.

Aminopeptidases↗
PubMed1988

[Influences of serum magnesium on measurements of serum parathyroid hormone].

The amino sequence recognizable parathyroid hormones (PTH) in lower and non-lower magnesemic groups in randomized samples were measured by using various kinds of the well established PTH kits. The levels of carboxy terminal, mid-region and intact PTH in lower magnesemic group were more decreased than these in non-lower magnesemic group. It is likely that the shortage of magnesium in serum makes a suppression of PTH secretion.

Humans↗
PubMed1988

[Parathyroid hormone and bone mineral content in male and female patients receiving hemodialysis].

Relative bone mineral content in the lumbar spine was measured by phantom B-MAs with the apparatus of computerized tomography in order to study the relationships between bone mineral content with age and parathyroid hormone in sera of randomized out- and in-patients and the hemodialysis patients. There exists a significant difference between male and female in the loss of bone mineral content of three groups.

Adult↗
PubMed1988

[The role of antineoplastic solution in transcatheter hepatic arterial embolization--in terms of survival rates affecting anticancer agents together with gelatin sponge].

In a multicentered randomized prospective study, hepatic arterial embolization using gelatin sponge (GS) alone or together with anticancer agents was performed in a total of 112 patients with hepatocellular carcinoma to ascertain the clinical availability of the anticancer agents combined with gelatin sponge. Envelopes, each of which contained a note mentioning one of the following three kinds of regimens, were allocated at random to the participating institutes: 1) GS + mitomycin C (MMC) 10 mg + adriamycin (ADR) 20 mg (group A, n = 45), 2) GS + MMC 10 mg + ADR 20 mg + 200 mg/day of oral 5-fluorouracil (5-FU) (group B, n = 36), and 3) GS + 200 mg/day of 5-FU (group C, n = 31). The envelopes so allocated were opened just prior to embolization, and the treatment was carried out as instructed. Survival rates were estimated according to the method of Kaplan-Meier for comparative analysis. The survival rate was significantly higher in group A than in group C on days 465 (p less than 0.05). It was also significantly higher in group B than in group C on days 279, 558 and 651 (p less than 0.05) as well as on days 372 and 465 (p less than 0.01). These observations suggest that this embolization using anticancer agents such as MMC and ADR, compared with the embolization using gelatin sponge alone, may exert a life-prolonging effect in patients with hepatocellular carcinoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

In vivo inhibition of aspartate aminotransferase in mice by L-hydrazinosuccinate.

L-Hydrazinosuccinate, which has been shown to be a slow-, tight-binding inhibitor of aspartate aminotransferase (EC 2.6.1.1) in vitro, was tested as an inhibitor in vivo of the enzyme as well as other pyridoxal enzymes. Intraperitoneal administration to mice at a dose of 0.6 mmol/kg rapidly decreased aspartate aminotransferase activities in liver and kidney cytosols to a minimal level lower than 10% of the original, and no appreciable reversal of the inhibition was observed after 24 h; at lower doses the activities were significantly recovered during the same period following an initial marked decrease. Of the other pyridoxal enzymes tested, alanine aminotransferase in liver was the most sensitive to the inhibitor. It was initially inhibited as severely as aspartate aminotransferase, but the inhibition was reversed considerably faster. Aspartate aminotransferase activities in brain and heart were less severely affected than those in liver and kidney; they were less markedly lowered initially and were substantially recovered after 24 h. Consistent with the observed organ specificity, heated extracts from brain and heart in the mice administered with the inhibitor showed relatively weak inhibitory activities in vitro to aspartate aminotransferase purified from pig heart, while the extracts from liver and kidney were strongly inhibitory.

Animals↗