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Biomedical subjects

Y Asada

Publications and source records attributed to Y Asada.

At least 199 records · Page 11Linked to original sources
PubMed1993

Expression of dipeptidyl aminopeptidase IV activity in human lung carcinoma.

Dipeptidyl aminopeptidase IV (DAP IV) staining was examined in various histological types of lung carcinomas to evaluate this enzyme activity. A total of 45 lung carcinomas were examined for their enzyme activity. Almost all (93.1%) cases of adenocarcinoma were positive for DAP IV activity, whereas all cases of squamous cell carcinoma, small cell carcinoma, large cell carcinoma and carcinoid were negative. DAP IV activity of microsomes in lung carcinomas was significantly higher in papillary adenocarcinomas than in squamous cell carcinomas. These data suggest that DAP IV may be a good marker to distinguish adenocarcinoma from other histological types of lung carcinoma.

Adenocarcinoma↗
PubMed1993

The effect of oxatomide on neutrophil oxygen radical generation.

The effect of oxatomide on reactive oxygen species (ROS) generated both by neutrophils and in a cell-free, xanthine-xanthine oxidase system was examined. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH.). Oxatomide significantly decreased neutrophil-generated O2-, H2O2 and OH. in a dose-dependent manner. H2O2 and OH. generated in a cell-free system were also reduced in the presence of oxatomide. The present study indicates that oxatomide decreases ROS generation presumably by inhibiting the neutrophil oxygen metabolism, and has the ability to scavenge H2O2 and OH.

Cell-Free System↗
PubMed1993

Protothecosis in a patient with systemic lupus erythematosus.

A rare case of protothecosis in a 40-year-old Japanese woman with systemic lupus erythematosus, under long-term prednisolone treatment is presented. The patient developed extensive ulcerative skin lesions after injury. The characteristic histopathological findings and biochemical sugar assimilation tests indicated infection by Prototheca wicherhamii. The lesions improved following treatment with amphotericin B. The immunodeficient state of this patient seemed to contribute to the infection with Prototheca.

Abscess↗
PubMed1993

Solid basal cell epithelioma (BCE) possibly originates from the outer root sheath of the hair follicle.

The presence and distribution of several cytokeratins (CKs) in 20 solid basal cell epitheliomas (BCEs) were investigated and compared with the pattern of CKs in normal epidermis, perilesional skin and in the outer root sheath (ORS) of the human hair follicle. Tissue samples were stained with monoclonal antibodies (MoAbs) against human CKs, using the APAAP technique. Additionally, CK profiles were assessed by gel electrophoresis and immunoblot technique. Cells of BCE and ORS were positively stained with the MoAb KL1, whereas the basal layer of normal epidermis remained negative. Six out of 20 BCEs were partially stained with the MoAb RPN1165, which also stained the lower ORS, but not the epidermal basal layer. Using SDS-PAGE and immunoblot, the CK profiles of BCE and ORS were almost identical, showing the presence of CKs 5, 6, 14, 16 and 17; the CK pattern of normal epidermis, however, showed the presence of CKs 1, 5, 10 and 14. Perilesional skin (< 5 mm) showed keratin changes similar to the BCE pattern; the basal layer was stained with the MoAb KL1 and the suprabasal layer was negative to MoAb CK1, in contrast to normal epidermis. Keratin analysis revealed a CK pattern of perilesional skin different from that of normal epidermis (CKs 1, 5, 6, 10, 14, 16 and 17). Our immunohistochemical and biochemical investigations underline the possible role of the lower ORS as a cellular pool for the generation of BCE.

Antibodies, Monoclonal↗
PubMed1993

[Histopathology of thrombotic thrombocytopenic purpura].

The most striking lesions of thrombotic thrombocytopenic purpura (TTP) are the subendothelial hyaline deposits and multiple occlusive thrombi. They are found in the small arteries, arterioles, and capillaries of many organs, especially the heart, brain, kidneys, and adrenal glands. Immunohistochemical examination demonstrates that the thrombi in TTP are strongly positive for von Willebrand factor (vWF) antigen, but only weakly for fibrinogen/fibrin. Electronmicroscopically, the thrombi in TTP were composed of tightly packed platelets, showing varying degrees of cytoplasmic alteration and degranulation with a small amount of interspersed fibrin and amorphous materials. Many etiological factors causing intravascular platelet aggregation have been postulated, including unusually large vWF multimers, platelet agglutinating proteins and immune abnormalities. All the lesions in TTP are strongly positive for vWF antigen. This result suggests that vWF multimers may play an important role in the pathogenesis of TTP.

Arteries↗
PubMed1992

Effects of antithrombotic drug, Y-20811 on mural thrombus formation and intimal thickening following intimal injury.

Inhibitory effect of Y-20811 on platelet thrombus formation induced by mechanical intimal injury and subsequent intimal fibrous thickening was studied. In the short term experiment, polyethylene tubing was inserted into the rabbit aorta and was drawn out one hour after with or without Y-20811 administration, then the rabbits were sacrificed. In the experiment for the quantitative analysis of platelet adhesion, 51Cr-labeled platelets were used. Radioactivities of 2cm length of the injured segment of the thoracic aorta and the proximal 2cm of the normal segment were measured. Radioactivity of the injured segment was significantly lower in rabbits treated with Y-20811 than the control ones. The mean thickness (area of thrombi/length of injured intima) and the maximal thickness of the mural thrombi in the Y-20811-treated rabbits were significantly lower than those in control rabbits. De-endothelialized area showed raised platelet thrombi in the control group and diffuse thin-layered platelet sheets in Y-20811-treated rabbits. In the long term experiment, polyethylene tubing was indwelled for 24 hours. Rabbits were sacrificed 10 days after drawing out the tubing. Through the experiment Y-20811 was injected intravenously every 24 hours. There was no significant difference between the control group and the Y-20811-treated one in both mean thickness and maximal thickness of the intimal fibromuscular thickening. The experiments indicate that Y-20811 has an inhibitory effect on platelet thrombus formation following intimal injury, but subsequent myointimal thickening is not inhibited by the drug.

Animals↗
PubMed1992

Replication of endothelial cells and smooth muscle cells induced in vivo by hypercholesterolaemia and materials released from platelet-rich white thrombus.

Endothelial cell injury is considered to be the primary event in atherogenesis. In this study, we investigated the effects of hypercholesterolaemia, and substances released from platelet-rich thrombi, individually and together on endothelial cells and the wall of the rabbit in vivo. We divided 24 rabbits into four groups: I was a control group on a normal diet; II was a tubing group on a normal diet, in which polyethylene tubing was inserted into the ascending aorta; III was a group being fed a cholesterol diet; and IV was a combined group being fed a cholesterol diet with polyethylene tubing in the ascending aorta. Segments from the descending thoracic and abdominal aortas which were not injured directly by tubing were examined morphologically and for [3H] thymidine incorporation into endothelial cells and smooth muscle cells. The descending aortas of groups II, III, and IV showed various degrees of endothelial cell damage. [3H]Thymidine incorporation into endothelial cells and aortic wall was increased in groups II, III, and IV (most in group IV) as compared with group I. These data indicate that hypercholesterolaemia and substances released from activated platelets and/or white mural thrombi can cause endothelial damage which may result in endothelial and smooth muscle cell proliferation. In addition, a combination of these two factors showed an additive effect on the endothelial injury and regeneration in vivo.

Animals↗
PubMed1992

Diagnostic usefulness of dipeptidyl aminopeptidase IV monoclonal antibody in paraffin-embedded thyroid follicular tumours.

Monoclonal antibodies to dipeptidyl aminopeptidase IV (DAP IV, EC 3.4.14.5) were raised and selectively applied to paraffin-embedded sections of thyroid carcinoma. Five monoclonal antibodies were found to stain paraffin sections of thyroid carcinomas. Using one of these antibodies (44-4), we studied retrospectively aberrant expression of DAP IV in thyroid carcinoma to determine whether immunohistochemical staining with DAP IV antibody is useful in pathological diagnosis. In almost all cases of thyroid follicular and papillary carcinoma, tumour cells were positive (99.0 per cent) with DAP IV, whereas the cases of follicular adenoma showed a low incidence (27.1 per cent) of positive staining. Follicular adenoma with incomplete capsular invasion had a higher positive incidence (50 per cent) than follicular adenoma without incomplete capsular invasion (9.6 per cent). In positive staining cases previously diagnosed as benign tumours, 11 benign cases reacting positively with DAP IV were rediagnosed as carcinoma after re-examination of more thyroid paraffin block sections or serial sections. These findings suggest that DAP IV monoclonal antibody is very useful in distinguishing thyroid follicular carcinoma from follicular adenoma.

Adenoma↗
PubMed1992

Bowel preparation for the total colonoscopy by 2,000 ml of balanced lavage solution (Golytely) and sennoside.

One of disadvantages of the Golytely preparation is that examinees have to drink as much as 4,000 ml of Golytely. To overcome this disadvantage, we designed a modified preparation regimen in which examinees have to drink only 2,000 ml of Golytely by taking sennoside orally. Bowel preparation was carried out in 297 examinees by this modified method. Examinees ate their usual diet and took 36 mg of sennoside orally on the night before the examination. On the day of the examination, the examinees drank a total of 2,000 ml of Golytely. No severe complications were noted and 97% of the examinees were able to drink the dose of 2,000 ml. Subjects who had also experienced bowel preparation by the modified method of Brown were asked to compare the two regimens, and only 1% preferred Brown's method while 73% preferred bowel preparation by our Golytely method. The result of bowel preparation by this method was excellent or good in 90 to 97% of the subjects at all sites in the colon and rectum. We conclude that bowel preparation for total colonoscopy using 2,000 ml of Golytely and sennoside is superior because it is highly acceptable to the examinees and provides excellent gut irrigation.

Adolescent↗
PubMed1992

Vascular contraction in perfused carotid arteries of cholesterol-fed rabbits.

The purpose of the present study was to investigate the effects of hypercholesterolemia on sympathetic vascular responsiveness in the perfused rabbit carotid artery. Two groups of rabbit carotid arteries were evaluated for the simultaneous measurement of noradrenaline (NA) release and vasoconstrictor response induced by electric nerve stimulation and for exogenous NA-induced vasoconstriction in vitro. One group of rabbits was fed a diet containing 0.5% cholesterol for 2 weeks and the other group was fed standard rabbit chow. By scanning electron microscopy, monocytes adhering to the endothelial cells and penetrating into the subendothelium were observed. Neither endothelial denudation nor platelet adhesion could be detected. Rabbit carotid arteries were cannulated and perfused with a physiological solution at a constant flow rate. The vessels were subjected to both transmural field stimulation (TFS; 1.5-24 Hz) and exogenous NA administration. TFS caused a frequency-dependent increase in endogenous NA release with subsequent pressor responses in both groups. Exogenous NA also induced a dose-dependent pressor response, but a significant reduction was observed in the cholesterol-fed group. Methoxamine induced a similar response in both groups. It was concluded that hypercholesterolemia decreased the sensitivity of extrajunctional alpha-receptors in the perfused rabbit carotid artery.

Animals↗
PubMed1992

Biotransformation of tabersonine in cell suspension cultures of Catharanthus roseus.

To investigate the reactions involved in the biosynthesis of vindoline from tabersonine, the bioconversion products formed when the latter compound was fed to cell suspension cultures of Catharanthus roseus were isolated and characterized. Two biotransformation products of tabersonine were isolated and shown to be lochnericine, which is formed by epoxidation of tabersonine at positions 14, 15, and lochnerinine, the 11-methoxylation product of lochnericine. The bioconversion ratio of the main biotransformation product, lochnericine, reached a value of 80.6% within three days.

Alkaloids↗
PubMed1992

The prognostic significance of vascular invasion in upper urinary tract transitional cell carcinoma.

The prognostic significance of vascular invasion was evaluated in a retrospective series of 30 patients with upper urinary tract cancer who underwent a potentially curative operation. Vascular invasion was found in 11 patients (36.7%). The incidence of vascular invasion was well correlated with tumor grade and stage. The incidence of metastases postoperatively was significantly higher in the patients with (72.7%) than without (21.1%) vascular invasion (p < 0.01). The survival rate of the patients with vascular invasion was significantly lower than in those without vascular invasion (p < 0.005). In multivariate Cox regression analysis the prognostic value of vascular invasion was independent of tumor stage and grade. These results indicate that vascular invasion should predict a more unfavorable outcome in patients with upper urinary tract cancer as an independent morphological indicator.

Adult↗
PubMed1992

Relationship between the changes in placental blood flow resistance assessed by Doppler technique and maternal serum placental aminopeptidases, which degrade vaso-active peptides, in pre-eclampsia.

Our study showed that there were statistically significant correlations between the systolic and diastolic ratio (S/D) of maternal uterine or umbilical artery and the levels of maternal serum aminopeptidase activities in pre-eclampsia. Kininase I was positively correlated with the S/D ratios, whereas placental leucine aminopeptidase (P-LAP) and aminopeptidase A were negatively correlated with the S/D ratios. It is known that the increased S/D ratios reflect the increased utero-placental blood flow resistance. Since our previous study showed that placental aminopeptidases degrade vasoactive peptides such as oxytocin, angiotensin and bradykinin, which the fetus actively produces, our present study suggests that the increased vascular resistance in feto-placental circulation in pre-eclampsia is partly controlled by changes in vaso-active peptides, via degradation by placental aminopeptidases.

Adult↗
PubMed1992

An epidemiological study of methicillin-resistant Staphylococcus aureus (MRSA) isolated from medical staff, inpatients, and hospital environment in one ward at our hospital.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important causative microorganisms for nosocomial infections. Recently, the incidence of isolation of MRSA has been increasing every year in Japan and is, notably, much more frequently found in inpatients than in outpatients. Therefore, we have done epidemiological studies of MRSA isolated from medical staff, inpatients, and the hospital environment in one ward of our hospital. Thereafter, we examined the antibiotic susceptibility (ABPC, DMPPC, CET, CMZ, IPM, GM, MINO, OFLX, EM, CLDM, VCM), phage typing, and coagulase typing of these MRSA. MRSA were isolated more frequently from anterior nares of inpatients than from doctors and nurses. MRSA were isolated more frequently from the environment near carriers of MRSA. Coagulase type II and phage type N.T. (not typable) were the dominant types of MRSA in our hospital (69% and 61%). MRSA strains were resistant to most antibiotics with a few exceptions (VCM, IPM, CMZ, CET). The high isolation frequency of MRSA in our hospital seems to suggest that inpatients who are carrying MRSA spread MRSA throughout the hospital environment and that the anterior nares of inpatients are the major MRSA harbor.

Air Microbiology↗
PubMed1992

Alpha 2-adrenoceptors mediate norepinephrine constriction of porcine pial veins.

The adrenergic innervation and alpha-adrenoceptor agonist-induced constrictions in isolated medium-size pial veins (OD 734 +/- 18 microns) of the pig were investigated. Using in vitro tissue bath techniques, we noted exogenously applied norepinephrine (10(-9) to 10(-5) M) induced venoconstriction with EC50 values of 1.71 x 10(-7) M, where EC50 is the concentration that produced 50% of (non-KCl) agonist-induced maximum constriction. The constriction was mimicked by clonidine but not by phenylephrine and was more effectively blocked by yohimbine than by prazosin. Results from histochemical studies demonstrated that porcine pial veins received a denser plexus of catecholamine fluorescence fibers than do pial arteries with similar outer diameter. These results suggest that norepinephrine-induced pial venoconstriction is mediated predominantly by alpha 2-adrenoceptors and that porcine pial veins have significantly greater sensitivity to the alpha-action of norepinephrine than that reported in pial arteries. These results add further support for adrenergic innervation in pial veins being of importance in regulating cerebral blood volume and intracranial pressure.

Adrenergic alpha-Agonists↗