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Biomedical subjects

Y Tsuda

Publications and source records attributed to Y Tsuda.

At least 181 records · Page 10Linked to original sources
PubMed1991

Nematocidal principles in "oakmoss absolute" and nematocidal activity of 2,4-dihydroxybenzoates.

Nematocidal principles obtained from oakmoss absolute were identified as methyl 2,4-dihydroxy-3,6-di-methylbenzoate (2), ethyl 3-formyl-2,4-dihydroxy-6-methylbenzoate (4), and ethyl 5-chloro-3-formyl-2,4-dihydroxy-6-methylbenzoate (7). In relation to their structures, the nematocidal activity of 2,4-dihydroxybenzoates of methyl to tetradecyl was tested and the strongest activity was found in the octyl ester (minimal lethal concentration = 13 microM).

Animals↗
PubMed1991

Development of active center-directed inhibitors against plasmin.

Active center-directed inhibitors of plasmin were designed based on the structure of specific substrates of plasmin and then synthesized. Their effects on plasmin were examined and the structure-inhibitory activity relationship was studied. N alpha-trans-4-Aminomethylcyclohexanecarbonyllysine 4-benzoylanilide (Tra-Lys-BZA) inhibited plasmin activities toward S-2251 and fibrin with IC50 values of 15 and 6.1 microM, respectively and N alpha-trans-4-aminomethylcyclohexane-carbonyllysine 4-benzylpiperidine amide (Tra-Lys-BPP) did not show any detectable inhibitory activity. Moreover, it was revealed that Tra-Lys-4-methoxycarbonylanilide inhibited plasma kallikrein more potently than plasmin.

Binding Sites↗
PubMed1991

Development of selective inhibitors against plasma kallikrein.

Specific plasma kallikrein inhibitors were designed and synthesized and their structure-activity relationship was studied. trans-4-Aminomethylcyclohexanecarbonyl (Tra)-lysyl-4-ethoxycarbonylanilide inhibited plasma kallikrein and plasmin with IC50 values of 23 and 210 microM, respectively, indicating that this compound is fairly specific to plasma kallikrein. Tra-arginyl-4-ethoxycarbonylanilide inhibited plasma kallikrein and plasmin with IC50 values of 16 and 480 microM, respectively. Tra-homoarginyl-4-carboxyanilide inhibited plasma kallikrein and plasmin with IC50 values of 14 microM and 1 mM, respectively. Finally, Tra-Arg(Mts)-4-acetylanilide (ACA) exhibited potent and selective inhibitory activity against plasma kallikrein (IC50 value for plasma kallikrein: 2 microM and for plasmin: 42 microM).

Amino Acid Sequence↗
PubMed1991

Barbaloin stimulates growth of Eubacterium sp. strain BAR, a barbaloin-metabolizing bacterium from human feces.

Eubacterium sp. strain BAR, isolated from human feces, transformed barbaloin to aloe-emodin anthrone in a basal medium lacking carbohydrate. Barbaloin remarkably stimulated the growth of strain BAR in the basal medium, the stimulative extent of the growth depending on the amount of barbaloin added. The addition of D-glucose, D-galactose, maltose, cellobiose, sucrose or D-amygdalin to the basal medium containing barbaloin caused a decrease of the growth stimulated by barbaloin to the growth level with each sugar, resulting in a complete inhibition of the barbaloin transformation. On the other hand, the addition of D-fructose, which itself stimulated the growth of strain BAR, further increased the growth in the presence of barbaloin and little inhibited barbaloin transformation. Nojirimycin bisulfite, a specific inhibitor of glucosidases, potently inhibited the growth with barbaloin, but did not affect the growth with glucose or cellobiose. Also, nojirimycin bisulfite completely inhibited the transformation of barbaloin to aloe-emodin anthrone. These results indicate that a unique enzyme capable of cleaving the C-glycosyl bond is induced in strain BAR by barbaloin and, consequently, strain BAR grows by utilizing as a nutrient the carbohydrate liberated from barbaloin. It is further suggested that the barbaloin-cleaving enzyme is inhibited by nojirimycin bisulfite and that the induction of the enzyme is repressed with D-glucose and D-galactose.

Anthracenes↗
PubMed1991

Diffuse endocardial thrombus in left ventricle associated with a case of hypereosinophilic syndrome.

A 16-year-old girl appeared with fever and dyspnea. In her peripheral blood, leukocytes were found to have increased up to 25,200/mm3, and eosinophils occupied 49% of the leukocyte population. By echocardiography, an abnormal echo layer which appeared to be thrombus was observed over the entire left ventricular endocardium including the posterior leaflet of the mitral valve, and mild mitral valve regurgitation was noted. After treatment, the abnormal echoes were markedly reduced simultaneously with the improvement of subjective symptoms.

Adolescent↗
PubMed1991

Left ventricular function in patients with stable systemic lupus erythematosus.

Echocardiography was used to compare the left ventricular function of 43 female patients with stable systemic lupus erythematosus with 93 healthy females in 3 age groups. Left ventricular systolic function was evaluated by the left ventricular ejection fraction and left ventricular diastolic function was evaluated by the diastolic descent rate of the anterior mitral leaflet (DDR), the ratio of mean systolic velocity to mean diastolic velocity in the left ventricular posterior wall (D/S ratio) and the ratio of peak mitral inflow velocity during the atrial filling period to that in the early filling period (A/E ratio). The left ventricular ejection fraction was not significantly different between patients and normal subjects. However, left ventricular diastolic function evaluated by these indexes in patients was different from normal subjects. These data suggest that left ventricular diastolic function is lower in patients with stable systemic lupus erythematosus than in normal subjects. It appears to deteriorate progressively with age. However, left ventricular systolic function remains normal.

Adolescent↗
PubMed1991

[Successful treatment of a pretreated elderly case of small-cell lung carcinoma with continuous five-day intravenous infusion of cisplatin plus etoposide].

A 78-year-old man was admitted to our hospital with dyspnea in June 1988, and diagnosed as having small-cell lung carcinoma by cytological findings of pleural effusion. He was treated three times with CAV (cyclophosphamide, doxorubicin, vincristine) therapy and a partial response was achieved. In March 1989, he was again admitted complaining of right dull hypochondralgia accompanied by enlargement of primary tumor in the right lower lobe of the lung and metastases to mediastinal and intraabdominal lymph nodes. Because it was an aged and recurrent case, he was treated with continuous five-day infusion of etoposide, 30 mg/m2/day and CDDP, 18.5 mg/m2/day. After the second course, subjective symptoms clearly disappeared and swelling of mediastinal and intraabdominal lymph nodes was markedly reduced on computed tomography. No severe side effects except for moderate myelosuppression, alopecia and nausea were observed. This regimen appears useful in the treatment of small-cell lung carcinoma in elderly patients.

Aged↗
PubMed1991

Hemodilution in cerebral infarcts.

To evaluate the effect of hypervolemic hemodilution on cerebral blood flow (CBF) two protocols have been performed: A) Ten randomly selected baboons have been treated with either low molecular dextrane (10 ml/kg) or normal saline (10 ml/kg). Regional cerebral ischemia was produced in all baboons. CBF increased selectively in the ischemic territory but not in the normally perfused tissue. B) Forty patients with acute cerebral ischemia were treated on day onset of symptoms with either dextrose, low molecular weight dextrane, hydroxyethyl starch or pentoxifylline. After intravenous infusion of the substances CBF increased only in the groups treated with dextrane- or starch-solution. Ischemic tissue benefitted more from hypervolemic hemodilution than normally perfused tissue. It was concluded that hypervolemic hemodilution leads to increase of cerebral blood flow, more in ischemic than in normally perfused brain tissue.

Acute Disease↗
PubMed1990

Synthesis of a trihexacontapeptide corresponding to the sequence 8-70 of eglin c and studies on the relationship between the structure and the inhibitory activity against human leukocyte elastase, cathepsin G and alpha-chymotrypsin.

A trihexacontapeptide corresponding to the sequence 8-70 of eglin c and its related peptides were synthesized by the conventional solution method and their inhibitory activity against human leukocyte elastase, cathepsin G and alpha-chymotrypsin was examined. Although synthetic eglin c (41-49) inhibited cathepsin G and alpha-chymotrypsin (Ki = 4.0 x 10(-5) M and 2.0 x 10(-5) M, respectively) but not leukocyte elastase, the synthetic trihexacontapeptide potently inhibited cathepsin G, alpha-chymotrypsin and leukocyte elastase (Ki = 1.8 x 10(-9) M, 1.4 x 10(-9) M and 2.2 x 10(-9) M, respectively). The relationship between the structure of eglin c and the inhibitory activity against the above enzymes is also described.

Amino Acid Sequence↗
PubMed1990

Effect of flunarizine on cerebral blood flow in baboons with or without focal cerebral ischaemia.

In baboons with or without regional cerebral ischaemia (achieved by transorbital clip of the middle cerebral artery), cerebral blood flow (CBF) was measured using the intra-arterial Xenon-133 technique during steady-state, slight hypotension, and hypocapnia before and after administration of various doses of the calcium antagonist flunarizine (0.5 mg kg-1, 1.0 mg kg-1, or 10 micrograms kg-1 min-1 over 30 min). In normal baboons flunarizine did not alter CBF significantly, but at reduced blood pressure it increased CBF by 19.9% owing to exaggerated vasodilatory autoregulation. During hypocapnia flunarizine impaired the physiological reduction in CBF owing to reduced vasoconstriction. In baboons with cerebral ischaemia, CBF measurements were stable and comparable with those in a control group using an arterial clip unless flunarizine was added. In a group of five flunarizine-treated animals, mean CBF after positioning of the clip was higher than in the control group. However, the increase in mean CBF varied significantly between animals, indicating that a secondary reduction in CBF due to postischaemic pathophysiological processes was not prevented consistently.

Animals↗
PubMed1990

Mineralocorticoid and renal receptor binding activity of 21-deoxyaldosterone.

Since several aldosterone metabolites are known to be active, we have assessed the mineralocorticoid biological and renal receptor binding activities of the aldosterone metabolites, 21-deoxyaldosterone (21-deoxy-Aldo), 21-deoxytetrahydroaldosterone (21-deoxy-THAldo), and 3 alpha, 5 beta-tetrahydroaldosterone (THAldo). We synthesized these steroids by bioreduction of aldosterone with intestinal bacteria. Mineralocorticoid agonist activity of 21-deoxy-Aldo, 21-deoxy-THAldo and THAldo, determined by bioassay using adrenalectomized rats, was 1-5%, less than 0.01%, and 0.1-0.5% that of aldosterone, respectively. 21-Deoxy-Aldo showed no antagonist activity. The relative affinity in competing with [3H]aldosterone for binding to mineralocorticoid receptors in adrenalectomized rat kidney cytosols was 94%, less than 0.01%, and less than 0.01% that of aldosterone. The relative binding affinity for rat renal glucocorticoid receptors was 23%, less than 0.01%, and less than 0.01% that of dexamethasone, and for corticosteroid-binding globulin 17%, less than 0.01%, and less than 0.01% that of cortisol. These results show that the naturally occurring steroid, 21-deoxy-Aldo, possesses mineralocorticoid agonist activity which is equivalent to that of 11-deoxycorticosterone, and has substantial affinity for rat renal mineralocorticoid and glucocorticoid receptors. The results also implicate the pathophysiological role of 21-deoxy-Aldo as a potential mineralocorticoid in 21-hydroxylase deficiency, where urinary excretion of this steroid is invariably elevated.

Adrenalectomy↗
PubMed1990

Intravascular behavior of a perfluorochemical emulsion.

The purpose of this study was to clarify the reason why two similar perfluorochemical (PFC) emulsions, namely a mixed PFC (perfluorodecalin: FDC and perfluorotripropylamine: FTPA) and an FDC emulsion, resulted in a very different survival time for the exchange-transfused rats. Supposing that some difference in the intravascular behavior of both emulsions would account for such a difference in efficacy, experiments on behavior of PFC emulsions were carried out focusing on the particle size. It was reconfirmed that larger PFC particles were eliminated from the blood stream much more rapidly than smaller particles with three FMIQ (perfluoro-N-methyldecahydroisoquinoline) emulsions. After the FDC + FTPA emulsion or the FDC emulsion were injected into rabbits, PFC particles in the blood tended to decrease in size. When each of the collected blood samples was incubated at 37 degrees C for 24 h, the FDC emulsion enlarged in size markedly, but the FDC + FTPA emulsion showed no change. The retention of PFC particles appeared to depend on the emulsion stability rather than simply on the emulsifying agent alone. These data showed that some differences were observed in intravascular persistence of the FDC + FTPA emulsion and the FDC emulsion, and suggested that the efficacy of PFC emulsions would reflect their behavior in the circulation.

Animals↗
PubMed1990

Retention of perfluorochemicals in tumor-bearing rats.

In order to study the elimination rate of perfluorochemical (PFC) emulsion from the blood and the PFC contents in the main organs of the tumor-bearing animals, Wistar strain rats were intramuscularly implanted with Walker 256 carcinosarcoma and 9L glioma cells were innoculated into the femoral muscle of Fischer rats. After 7 d the Wistar rats received an injection of 4 g PEC/kg of a PFC emulsion. The Fischer rats received a similar injection after 11 d. The rats injected with the PFC emulsion were periodically sacrificed for a week. There was no significant difference in PFC contents in the blood and main organs between normal rats and the tumor-bearing rats with either Walker 256 carcinosarcoma or 9L glioma. The PFC contents in Walker tumor were about 10 times as much as those of 9L tumor. The innoculated tumors did not substantially affect the PFC retention in the blood and the accumulation of PFC in main organs after intravenously injected with the PFC emulsion.

Animals↗
PubMed1990

Amino acids and peptides. XXVIII. Synthesis of peptide fragments related to eglin c and studies on the relationship between their structure and effects on human leukocyte elastase, cathepsin G and alpha-chymotrypsin.

Various peptide fragments related to eglin c, which consists of 70 amino acid residues, were synthesized by a conventional solution method and their inhibitory effects on leukocyte elastase, cathepsin G and alpha-chymotrypsin were examined. Among them, H-Arg-Glu-Tyr-Phe-OMe (eglin c 22-25) and H-Ser-Pro-Val-Thr-Leu-Asp-Leu-Arg-Tyr-OMe (eglin c 41-49) inhibited cathepsin G and alpha-chymotrypsin but not leukocyte elastase, while H-Thr-Asn-Val-Val-OMe (eglin c 60-63) inhibited leukocyte elastase but not cathepsin G or alpha-chymotrypsin, although eglin c potently inhibited leukocyte elastase, cathepsin G and alpha-chymotrypsin. These results indicated that the interaction sites of eglin c with leukocyte elastase, cathepsin G and alpha-chymotrypsin might be different.

Amino Acid Sequence↗
PubMed1990

[Two cases of amyopathic dermatomyositis with fatal rapidly progressive interstitial pneumonitis].

Two middle-aged women showed typical erythematous heliotrope eruption and Gottron's sign without any symptom of myositis. The patients were diagnosed as 'amyopathic dermatomyositis' because of normal serum CPK levels, normal EMG and no histological abnormality by muscle biopsy. Clinical manifestations improved by the treatment with corticosteroids. During tapering of corticosteroids, however, intersititial pneumonitis developed and rapidly progressed. The first patients was treated with methylprednisolone pulse therapy, azathiopurine and methotrexate. The second patients was treated with betamethazone, methlprednisolone pulse therapy and cyclosporin A. In spite of these extensive immunosuppressive therapies, both patients died of pulmonary insufficiency a few months after admission. In the literature there has been only several cases of amyopathic dermatomyositis and only one case with fatal rapidly progressive interstitial pneumonitis. A new approach to the treatment of this disease should be made.

Autoimmune Diseases↗