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Biomedical subjects

K Wada

Publications and source records attributed to K Wada.

At least 433 records · Page 24Linked to original sources
PubMed1994

Effects of ischemia-reperfusion injury on myocardial single pass extraction and retention of Cu-PTSM in perfused rat hearts: comparison with 201T1 and 14C-iodoantipyrine.

The effects of ischemia-reperfusion-induced myocardial damage on the single pass extraction and retention of 64Cu-pyruvaldehyde-di(N4-methylthiosemicabazone) (64Cu-PTSM) in perfused rat hearts were compared to these effects on that of 201T1 and 14C-iodoantipyrine. 201T1 and 14C-iodoantipyrine did not show significant changes, but in the case of 64Cu-PTSM, the single pass extraction and retention was reduced with reperfusion. These findings indicate that ischemia-reperfusion-induced myocardial damage decrease the generator-produced 62Cu-labeled 62Cu-PTSM extraction and retention, and that 62Cu-PTSM might have potential not only as a blood flow tracer but also as a functional tracer.

Animals↗
PubMed1994

Renal and hormonal responses to repeated treatment with enalapril in non-azotemic cirrhosis with ascites.

Since a single dose of the angiotensin-converting enzyme inhibitor enalapril was shown to cause natriuresis in cirrhosis in a previous study, we investigated whether repeated doses of this substance would sustain a favorable renal effect in cirrhosis. Ten milligrams of enalapril maleate were administered once a day for 8 days to ten patients with non-azotemic cirrhosis and ascites. Enalapril reduced blood pressure significantly at 4 to 12 h (systolic blood pressure) and 2, 6, and 8 h (diastolic blood pressure) on day 2, compared to pretreatment (day 0) values, but this depressor effect decreased on day 8. No change in heart rate could be detected. Enalapril significantly suppressed serum angiotensin-converting enzyme activity and plasma aldosterone concentration (p < 0.001 to 0.01), which were elevated prior to treatment, with pretreatment values of 25.8 +/- 1.8 IU/l for serum angiotensin-converting enzyme activity and 241 +/- 67 pg/ml for plasma aldosterone concentration. This drug caused a 12 to 24% increase (p < 0.05 to 0.01) in mean daily urinary volume and a 40 to 54% increase (p < 0.001 to 0.01) in mean daily urinary sodium excretion from the respective pretreatment baselines during the 8-day period. Creatinine clearance was improved (p < 0.05) by the treatment, with mean improvement values from 24 to 34% above the pretreatment value of 47.4 +/- 4.3 ml/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Burkholderia (formerly Pseudomonas) cepacia porin is an oligomer composed of two component proteins.

The 81 kDa protein (designated OpcPO) which forms a diffusion pore in the outer membrane of Burkholderia (formerly Pseudomonas) cepacia has a unique characteristic in that when the purified protein is heated it yields a major 36 kDa protein (designated OpcP1) and a minor 27 kDa protein (designated OpcP2). Moreover, incubation of OpcPO in citrate buffer at pH 3.0 produced an unusual dissociation into 72 kDa and 27 kDa proteins. For the characterization of OpcPO and its derivatives, OpcP1 and OpcP2 from purified OpcPO were isolated by preparative SDS-PAGE. Reconstitution of OpcPO using purified preparations of OpcP1 and OpcP2 indicated that these derivatives were not proteolytic fragments of OpcPO. Moreover, immunoblot assays with murine polyclonal antisera specific for OpcP1 and OpcP2 yielded the following results: (i) OpcP1 and OpcP2 are immunologically distinguishable proteins; (ii) the unusual dissociation of OpcPO in citrate buffer at pH 3.0 resulted in the release of OpcP2 from OpcPO, and the resulting 72 kDa protein was probably an oligomer of OpcP1; (iii) purified OpcP1 itself produced two additional 53 kDa and 72 kDa proteins spontaneously following elution from the bottom of the SDS-PAGE gel. From these findings, it was concluded that OpcPO is formed by the non-covalent association of OpcP2 with an oligomer of OpcP1 that has the ability to self-assemble.

Antibodies, Bacterial↗
PubMed1994

Prevalence of tobacco smoking among junior high school students in Japan and background life style of smokers.

In order to estimate the prevalence of tobacco smoking among junior high school students in Japan and to assess certain characteristics of smokers, the authors surveyed 5240 students aged between 12 and 15 years. In terms of both the number of subjects and of schools, this was the first major survey of Japanese junior high schools on the relationship between tobacco smoking and the background life styles of smokers. Of all students, 30.5% of males, 13.3% of females and 22.2% of the total were lifetime smokers; 3.3%, 0.8% and 2.2%, respectively, were daily smokers. As the frequency of tobacco smoking increased, the regularity of the life style routine was significantly more disturbed, and school and family life were significantly less relaxed. The authors suggest that the strengthening of family cohesion would be an effective preventive strategy in Japan.

Adolescent↗
PubMed1994

[A study of postmortem infectious lesions of bacteremia and fungemia patients--relationship between fungemia and deep mycoses].

Postmortem infectious lesions were analyzed in 63 patients with bacteremia and fungemia. Bacterial infection was found in 36 patients, deep mycoses in 27 and cytomegalovirus infection in 7. Among deep mycoses patients, yeast was noticed in 17, Aspergillus in 13 and Mucor in one. Infectious lesions were not observed in 10 cases. Fifteen cases of 23 leukopenic patients were complicated with deep mycoses. Deep mycoses was noticed in 43% of bacteremia and fungemia patients, but not in candicemia patients. Fungemia due to Candida was related to blood access, however, not to deep mycoses. On the other hand, disseminated mycoses was found in 4 of 5 cases with Trichosporon beigelii fungemia. T. beigelii infection is noticeably life-threatening to the immunocompromised host.

Adolescent↗
PubMed1994

Endocrine features in eutestosteronemic women with polycystic ovaries.

We attempted to assess the association between hyperandrogenemia and inappropriate gonadotropin secretion in women with polycystic ovaries (PCO). Thirty-one patients diagnosed as PCO by ultrasonography were divided into two subgroups: 17 with high serum total testosterone (T) level (> or = 0.5 ng/ml) and 14 with normal serum total T level (< 0.5 ng/ml). Both subgroups presented for the complaints of oligomenorrhea and/or hirsutism. The control group consisted of 15 women with regular ovulation for reference data collection. The PCO subjects with normal T, but not those with high T, revealed remarkable depletion of sex hormone binding globulin (SHBG), as compared with control. The PCO subject groups with high and normal serum T did not differ with respect to estrogen level, androgen level, follicle-stimulating hormone and prolactin levels, and SHBG concentration. Solely serum luteinizing hormone (LH) level was observed to be higher in those with high T, as typical features, than another subgroup or control. These data suggest that an increase in bioactive T as a result of decrease in serum SHBG or LH elevation may contribute to ovarian dysfunction in the patient with PCO.

Adult↗
PubMed1994

Possible evidence for estrone-specific binding sites in human uterine endometrial carcinoma.

Estrone (E1), a principal estrogen in postmenopausal women, may have profound consequences in the maintenance and progression of hormone-sensitive endometrial carcinoma. This study was designed to investigate the specific binding sites for E1 in the tumor and in the normal endometrium. The binding of [3H]E1 to the cytosolic fraction and KCl-soluble nuclear fraction from 3 endometrial carcinomas showed saturation kinetics with an apparent equilibrium dissociation constant of approximately 37 and 50 nM, respectively. The specific binding site of E1 was also found in 3 normal endometria. However, the binding capacity in the endometrial carcinoma increased to 1.5-fold of that in the normal endometrium. E2 did not affect [3H]E1 binding to any subcellular fraction from endometrial carcinoma specimens. These findings demonstrate the presence of specific binding sites for E1 in human endometrial carcinoma. The endometrial carcinoma growth may be mediated, at least in part, by E1 and its binding site interaction.

Binding Sites↗
PubMed1994

Differential aging pattern of cerebral accumulation of radiolabeled glucose and amino acid in the senescence accelerated mouse (SAM), a new model for the study of memory impairment.

Using an accelerated senescence-prone model mouse strain, SAMP8, with spontaneously occurring age-related deficits in learning and memory, cerebral glucose and amino acid accumulation were investigated to study the metabolic abnormalities in relation to age. The findings were compared with those in an accelerated senescence-resistant mouse strain, SAMR1, without deterioration of ability in learning and memory. [14C]-2-Deoxyglucose accumulation in the SAMP8 brain was normal at 1 month of age but decreased from 2-3 months of age onwards. In contrast, tyrosine accumulation was unchanged from 1 to 5 months of age. The impairment of memory in the SAMP8 at 2-3 months of age corresponded with the decrease in [14C]-2-deoxyglucose accumulation, but was not related to Tyr. This animal model may help provide new information on the metabolic changes in aging.

Aging↗
PubMed1994

Cu-ATSM, an intracellular-accessible superoxide dismutase (SOD)-like copper complex: evaluation in an ischemia-reperfusion injury model.

We have reported a stable superoxide dismutase (SOD)-like copper complex, Cu-ATSM, which shows high membrane permeability and distribution to the brain or heart. In this study, we evaluated the protective effects of Cu-ATSM on superoxide-mediated tissue damage caused by ischemia-reperfusion using an isolated perfused rat heart model. Lipid peroxidation levels in the Cu-ATSM treated group were lower than those in the non-treated group. Furthermore, released creatine phosphokinase into the perfusate, a marker of tissue damage, was reduced by Cu-ATSM treatment. These results indicated the possibility of Cu-ATSM being an effective SOD-like drug for the treatment of superoxide-mediated damage, such as ischemia-reperfusion injury.

Animals↗
PubMed1994

The mechanism of arachidonic acid release in collagen-activated human platelets.

The mechanism of arachidonic acid (AA) release in collagen-activated human platelets was studied. An arachidonic acid metabolite, thromboxane B2 (TXB2), was formed in parallel with the formation of phosphatidic acid (PA) without formation of lysophosphatidic acid (lysoPA) or lysophosphatidylinositol (lysoPI) in the absence of extracellular Ca2+, suggesting that AA was released from PI via a PI-specific phospholipase C (PI-PLC)/diacylglycerol (DG) lipase/monoacylglycerol (MG) lipase pathway under the cytosolic low Ca2+ concentrations. Moreover, solubilized DG lipase and MG lipase could hydrolyze the substrates at basal cytosolic free Ca2+ concentrations. Subsequently, the relationship of cytosolic free Ca2+ concentrations and formation of AA metabolites was analyzed using Ca2+ ionophore, A23187. Collagen was able to induce a release of small amounts of AA under basal cytosolic Ca2+ conditions. However, a release of large amounts of AA was induced by phospholipase A2 activated by both collagen-receptor occupancy and elevated Ca2+ levels. A TXA2 mimetic agonist, STA2 induced all the responses except for AA release. From these results, the mechanism of AA release and signal transduction in collagen-activated human platelets is discussed.

Arachidonic Acid↗
PubMed1994

Plasma urokinase-type plasminogen activator in patients with leukemias.

Plasma levels of urokinase-type plasminogen activator (u-PA) were measured with an enzyme-linked immunosorbent assay in patients with leukemias. As compared with healthy subjects (0.73 +/- SD 0.17 ng/ml), plasma u-PA antigen level was markedly elevated in patients with acute promyelocytic leukemia (APL) (1.76 +/- 0.89 ng/ml) at disease onset. Mean u-PA concentrations in patients with other acute nonlymphoblastic leukemia (0.57 +/- 0.51 ng/ml), acute lymphoblastic leukemia (0.77 +/- 0.82 ng/ml) and chronic myelocytic leukemia in blastic crisis (1.30 +/- 1.35 ng/ml) were not significantly elevated, but some of them showed an elevation of plasma u-PA. Plasma u-PA values were correlated with some of the fibrinolytic parameters such as FDP and D-dimer. Plasma u-PA antigen was decreased after the administration of antileukemic drugs in patients with APL. These results suggest that the coagulopathy in patients with various leukemias may in part be associated with u-PA release from the leukemic cells, especially in patients with APL.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

[Brainstem mechanisms of vocalization analyzed by electrical stimulation and chemical stimulation of sodium glutamate in cats].

The functional connection between the midbrain and the lower brain structures which organize vocalization was investigated in cats. To induce vocalization, repetitive electrical stimulation (0.2ms, 10-300 microA, 100Hz, lasting for 5 to 10s) was delivered to the caudal part of the ventrolateral periaqueductal gray (PAG), adjacent reticular formation (RF) or the pontine call site (PCS) which is located in the ventrolateral pontine RF. In Ketamine-anesthetized cats (n = 12), the stimulus threshold was the lowest in the ventrolateral PAG, and the stimulus threshold within the RF near the PAG tended to be higher than that in the PAG. In the effective RF area, the stimulus threshold was lower in the ventral area than that in the dorsal area. The effective area extended from the PAG through the RF to the PCS. The stimulus threshold around the PCS was the lowest in all animals. The size of the effective area was about 1 to 1.5mm in diameter within the PAG and the RF, and was wider than that in the PCS, which was about 0.5 to 1.0mm in diameter. There was a tendency for a wider effective area to correlate with a higher stimulus threshold. These results suggest that axons from the PAG area pass through the nearby RF and then compose a narrower fiber bundle in the PCS. In unanesthetized decerebrate cats (n = 5), a microinjection of glutamate, (2M sodium glutamate dissolved in 0.1M phosphate buffer (pH = 7.4)), was made with a glass micropipette (tip outer diameter: 200 microns) attached to a microsyringe with a polyethylene tube.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Antihypertensive effect of the novel water-soluble calcium antagonist (+/-)-3-(4-allyl-1-piperazinyl)-2,2-dimethylpropyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate dihydrochloride in rats.

The antihypertensive effect of (+/-)-3-(4-allyl-1-piperazinyl)-2,2-dimethylpropyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate dihydrochloride (NKY-722, CAS 117241-46-0) was examined in conscious spontaneously hypertensive rats (SHR), normotensive Wistar rats (NWR) and anesthetized NWR, and its vasodilatory effect was investigated in the perfused NWR mesenteric vascular bed. NKY-722 and nicardipine administered intravenously (10-100 micrograms/kg) and orally (0.3-10 mg/kg) lowered blood pressure dose-dependently with an increase in heart rate in conscious SHR and NWR. The effects of NKY-722 were slower in onset and longer-lasting than those of nicardipine, and were more marked in SHR than in NWR. The effect of NKY-722 was roughly the same as that of nicardipine on intravenous administration. However, NKY-722 was 4-8 times more potent than nicardipine on oral administration. In anesthetized NWR, the hypotensive effects of NKY-722 administered via the femoral vein, portal vein and duodenum were examined in comparison with those of nicardipine. The findings suggest that NKY-722 is more efficiently absorbed from the gastro-intestinal tract and more resistant to the hepatic first pass effect than nicardipine. In the perfused NWR vascular bed, NKY-722 and nicardipine (0.01-1.0 microgram) attenuated the pressor response to KCl dose-dependently. The effect of NKY-722 was slower in onset and longer-lasting than that of nicardipine. In conclusion; NKY-722 has a potent, slow-onset and long-lasting antihypertensive activity, which is mainly attributed to its slow-onset and long-lasting vasodilatory action. NKY-722 is expected to be a useful antihypertensive drug.

Anesthesia↗