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T Ohta

Publications and source records attributed to T Ohta.

At least 559 records · Page 31Linked to original sources
PubMed1996

Inhibition of endothelium-dependent relaxation by hemoglobin in rabbit aortic strips: comparison between acellular hemoglobin derivatives and cellular hemoglobins.

Hemoglobin (Hb)-based artificial oxygen carriers are supposed to induce vasoconstriction through the inactivation of endothelium-derived relaxing factor (EDRF). We examined the vasoconstrictive activity of acellular Hb and cellular Hb solutions in rabbit aortic strips. Unmodified Hb, pyridoxalated Hb, bovine unmodified Hb, haptoglobin-Hb complex (Hp-Hb), and polyoxyethylene glycol-conjugated Hb (PEG-Hb) were used as acellular Hbs having different molecular masses. Cellular Hbs included liposome-encapsulated Hb and red blood cells (RBC). In the first experiment, Hb (10 ng/ml to 1 mg/ml) was cumulatively added to the tissues in which steady-state relaxation was evoked by acetylcholine (ACh) after precontraction induced by phenylephrine. Although all Hb solutions induced a dose-dependent reversal of ACh-induced relaxation, the most potent vasoconstrictive effect was noted with acellular Hbs, and their contractile activities were almost the same independent of molecular mass. On the other hand, liposome-Hb and RBC showed reduced potencies in this order. These results indicate the importance of cellularity as the major factor determining Hb-related EDRF inactivation. In another experiment, the tissues were exposed to Hb at 0.01, 0.1, or 1 mg/ml for 30 min and ACh-induced relaxation was recorded after the complete removal of Hb in an organ bath chamber. Exposure to unmodified Hb at > 0.1-mg/ml concentrations significantly reduced the ACh-induced relaxation, whereas the relaxation was not affected by PEG-Hb, Hp-Hb, liposome-Hb, or RBC. These results suggest that unmodified Hb might be persistently associated with tissues and thereby inhibit ACh-induced relaxation. From these findings, we propose two attributes of Hb-related inhibition of endothelium-dependent relaxation: Acellular Hbs inhibit EDRF more efficiently in the luminal space than cellular Hbs, and unmodified Hb can also inhibit it adluminally and/or adventitially.

Acetylcholine↗
PubMed1996

Selective hypothermic perfusion of canine brain.

A method for selective brain cooling by profound hemodilution with cold Ringer's lactate solution was previously reported in 1992. We recently modified this technique by combining it with an ultrafiltration and rewarming circuit between the left jugular vein and the inferior vena cava. We used 12 beagle dogs to study the efficacy of selective cerebral hypothermia induced by this modified technique. The brain temperature decreased to 28 degrees C within 5.4 +/- 2.7 minutes and to 20 degrees C within 15.5 +/- 9.4 minutes. The lowest brain and rectal temperatures were 17.0 +/- 1.8 degrees C and 32.1 +/- 2.2 degrees C, respectively. All animals survived in good condition without evidence of neurological deficits until they were killed at 10 weeks. Histological examination of the brains with 2,3,5-triphenyltetrazolim chloride demonstrated no evidence of ischemic lesions, and even in the hippocampus, there was no evidence of ischemic neuronal damage.

Animals↗
PubMed1996

Symptomatic hypertrophic pacchionian granulation mimicking bone tumor: case report.

OBJECTIVE AND IMPORTANCE: Osteolytic lesions can be seen in various diseases, and they also resemble the markings normally found on the cranium. We present a rare case of symptomatic hypertrophic pacchionian granulation mimicking bone tumor in the calvaria. CLINICAL PRESENTATION: A 46-year-old woman suffered from a small hump accompanied by pain in the right frontoparietal region. A plain radiograph revealed two punched-out lesions. Precontrast-enhanced computed tomographic scans demonstrated hypodense masses, with partial defect of the outer table of the cranium. Magnetic resonance imaging demonstrated hypointense masses in the T1-weighted image and hyperintense masses in the T2-weighted image, with capsule-like contrast enhancement by gadolinium diethylenetriamine penta-acetic acid. INTERVENTION: The masses were totally resected with attached bone and dura. One of them had destroyed the outer table of the cranium. The affected portions of the masses lacked the dura and partially adhered to the brain surface. Histologically, hypertrophic pacchionian granulation was diagnosed. CONCLUSION: The patient has had no recurrence for 2 years. This case suggests the need to include hypertrophic pacchionian granulation in the differential diagnosis of punched-out lesions.

Cranial Sinuses↗
PubMed1996

Prospective evaluation of skin surface electropotentials in Japanese patients with suspicious breast lesions.

The biofield breast examination (BBE) is a new, noninvasive and cost-effective method for diagnosing breast lesions currently undergoing multicenter evaluation in the USA and Europe. The test analyzes subtle differences in electrical potential caused by dysregulated epithelial proliferation. This report summarizes a prospective evaluation of BBE in a population of 101 patients with suspicious breast lesions scheduled either for open surgical biopsy or fine needle aspiration biopsy. Of the 101 patients included in the study, 49 were found to have a breast malignancy and 52 were found to have a benign breast lesion. BBE correctly identified 44 of 49 biopsy-proven cancers (sensitivity=90%) and correctly indicated no cancer in 31 of 52 biopsy-proven benign cases (specificity=60%). Sensitivity increased to 95% for cancers less than 2.5 cm in size. These results indicate that BBE may be an effective adjunctive test to help to resolve abnormalities discovered by physical examination or other screening methods.

Adult↗
PubMed1996

Expression of oncogene products, anti-oncogene products and oncofetal antigens in intraductal papillary-mucinous neoplasm of the pancreas.

A few previous studies have demonstrated the expression or mutations of oncogenes and anti-oncogenes as well as that of oncofetal antigens in intraductal papillary-mucinous neoplasm of the pancreas. In this study, we have investigated the immunohistochemical expression of oncogene (ras and c-erbB-2) and anti-oncogene (p53 and retinoblastoma [Rb]) products and oncofetal antigens (CEA, CA19-9 and DUPAN-2) in nine such tumours of the pancreas. In normal pancreas (5 cases), the Rb gene product and CA19-9 were expressed in all cases, while ras and c-erbB-2 gene products, p53 protein, CEA and DUPAN-2 were not expressed. In intraductal papillary-mucinous tumours (n = 9), ras, c-erbB-2, p53 and Rb gene products were present in 4/9 (44%), 7/9 (78%), 0.9 (0%) and 6/9 (67%) cases, respectively. CEA, CA19-9 and DUPAN-2 were expressed in 8/9 (89%), 9/9 (100%) and 2/9 (22%) cases respectively. In invasive ductal adenocarcinoma of the pancrease (7 cases), ras, c-erbB-2, p53 and Rb gene products were expressed in 3/7 (43%), 6/7 (86%), 2/7 (29%) and 3/& (43%) cases respectively. CEA, CA19-9 and DUPAN-2 were expressed in 7/7 (100%), 7/7 (100%) and 6/7 (86%) cases, respectively. The extent and intensity of the expression of these antigens was greater in invasive ductal adenocarcinomas. These data suggest that activation of ras and c-erbB-2 oncogenes and inactivation of Rb anti-oncogene may contribute to the development and progression of intraductal papillary-mucinous tumours of the pancreas and that there is neo-expression of CEA and DUPAN-2 during the development and progression of these tumours.

Adenocarcinoma, Mucinous↗
PubMed1996

A 38 kDa precursor protein of aqualysin I (a thermophilic subtilisin-type protease) with a C-terminal extended sequence: its purification and in vitro processing.

The precursor of aqualysin I, an extracellular subtilisin-type protease produced by Thermus aquaticus, consists of four domains: an N-terminal signal peptide, an N-terminal pro-sequence, a protease domain, and a C-terminal extended sequence. In an Escherichia coli expression system for the aqualysin I gene, a 38 kDa precursor protein consisting of the protease domain and the C-terminal extended sequence is accumulated in the membrane fraction and processed to a 28 kDa mature enzyme upon heat treatment at 65 degrees C. The 38 kDa precursor protein is separated as a soluble form from denatured E. coli proteins after heat treatment. Accordingly, purification of the 38 kDa proaqualysin I was performed using chromatography. The purified precursor protein gave a single band on SDS-polyacrylamide gels. The precursor protein exhibited proteolytic activity comparable to that of the mature enzyme. The purified precursor protein was processed to the mature enzyme upon heat treatment. The processing was inhibited by diisopropyl fluorophosphate. The processing rate increased upon either the addition of mature aqualysin I or upon an increase in the concentration of the precursor, suggesting that the cleavage of the C-terminal extended sequence occurs through an intermolecular self-processing mechanism.

Amino Acid Sequence↗
PubMed1996

Expression of apolipoprotein A-1 mRNA in normal intrahepatic biliary tree.

Our previous study demonstrated that apolipoprotein A-1 (apo A-1) immunoreactive peptides were located diffusely in the cytoplasm, not only of human normal hepatocytes, but also of intrahepatic bile ducts and peribiliary glands. It is important to determine whether the presence of these immunoreactive peptides in intrahepatic biliary tree is caused by pinocytosis from the bile, or by intracellular protein synthesis. Thus, we investigated whether apo A-1 is synthesized by cells that line the biliary tree. Normal human liver samples obtained at surgery were used; and the expression and distribution of apo A-1 mRNA in normal human liver tissues were examined, using in situ hybridization histochemistry with a 35S-labeled oligonucleotide probe specific for apo A-1. On the autoradiogram, many silver grains were found to be distributed uniformly in hepatocytes. In addition, an appreciable apo A-1 mRNA signal was also observed in both the surface epithelial lining of the bile ducts and the epithelial cells of the peribiliary glands. In conclusion, these findings suggest that the apo A-1 found in bile is secreted both by hepatocytes and by intrahepatic bile duct cells and peribiliary glands.

Aged↗
PubMed1996

Age-dependent alteration of the serum-unbound fraction of nicardipine, a calcium-channel blocker, in man.

To determine whether the age-dependent increase in the pharmacological effect of calcium-channel blockers is a result of age-dependent alteration of the unbound fraction the drug in serum, the unbound fraction of the nicardipine was investigated in the serum of 38 adults. The unbound concentration of nicardipine in serum to which nicardipine (205.4 ng mL-1) had been added was determined by ultracentrifugation to range from 0.49 to 4.01% (mean +/- s.d., 1.55 +/- 0.78%). Non-glycosylated albumin was most strongly correlated with age (r = 0.901). Total bilirubin was weakly correlated with age whereas levels of alpha-1-acid glycoprotein, triglycerides and glycosylated albumin were not correlated with age. A significant (P < 0.01) linear correlation was obtained between the unbound fraction of nicardipine and parameters such as age, albumin, albumin/globulin ratio, albumin/glycosylated albumin ratio, non-glycosylated albumin and total bilirubin. To assess the relative effect of each variable on the unbound fraction of nicardipine, stepwise multiple linear regression was performed using age and biochemical parameters. The three variables (non-glycosylated albumin, total bilirubin and age) were entered into the regression equation. The results of this study showed that the major ligand of nicardipine in serum was non-glycosylated albumin, which decreased with age. It was, moreover, shown that the serum-unbound concentration of nicardipine increased with age. This finding would be one factor accounting for the increase in the pharmacological effect of nicardipine with age. In addition, our predicted model for the unbound fraction of nicardipine might be useful in determining the appropriate nicardipine dose for the elderly.

Adult↗
PubMed1996

Acetylpolyamine amidohydrolase from Mycoplana ramosa: gene cloning and characterization of the metal-substituted enzyme.

We have cloned a gene (aphA) encoding acetylpolyamine amidohydrolase from Mycoplana ramosa ATCC 49678, (previously named Mycoplana bullata). A genomic library of M. ramosa was screened with an oligonucleotide probe designed from a N-terminal amino acid sequence of the enzyme purified from M. ramosa. Nucleotide sequence analysis revealed an open reading frame of 1,023 bp which encodes a polypeptide with a molecular mass of 36,337 Da. This is the first report of the structure of acetylpolyamine amidohydrolase. The aphA gene was subcloned under the control of the trc promoter and was expressed in Escherichia coli MM294. The recombinant enzyme was purified, and the enzymatic properties were characterized. Substrate specificities, Km values, and Vmax values were identical to those of the native enzyme purified from M. ramosa. In the analysis of the metal-substituted enzymes, we found that the acid limb of pH rate profiles shifts from 7.2 for the original zinc enzyme to 6.6 for the cobalt enzyme. This change suggests that the zinc atom is essential for the catalytic activity of the enzyme similarly to the zinc atom in carboxypeptidase A.

Actinomycetales↗
PubMed1996

Motoo Kimura.

Explore the source record for details and available documents.

Genetics↗
PubMed1996

The effect of 1,24(R)(OH)2D3 cream and ointment on epidermal proliferation and differentiation in mice.

BACKGROUND: The 1,24(R)(OH)2D3 (tacalcitol) ointment (2 micrograms/g) is available commercially as an antipsoriatic drug in Japan, but the cream preparation of tacalcitol is still under development. OBJECTIVE: This study was conducted to compare the ability of tacalcitol cream and ointment to inhibit epidermal proliferation and induce epidermal differentiation. METHODS: We measured the ornithine decarboxylase activity and type I transglutaminase activity as indices of proliferation and differentiation, respectively, in hairless mice. RESULTS: These effects were statistically equal to those of the ointment preparation at the same dose, 2 micrograms/g, without inducing hypercalcemia. CONCLUSIONS: These findings suggest that topical application of 1,24(OH)2D3 cream (2 micrograms/g) might have the same potency as the ointment formulation in the treatment of psoriasis.

Administration, Topical↗
PubMed1996

Effects of alendronate on plasma calcium levels, urinary calcium excretion, and bone resorption markers in normal rats: comparison with elcatonin, synthetic eel calcitonin.

In normal rats given alendronate (0.01-6.25 mg/kg) or elcatonin (synthetic eel calcitonin; 0.32-8.0 U/kg), changes in urinary calcium (Ca), pyridinoline (Pyr), and deoxypyridinoline (D-Pyr) excretion during the hypocalcemic response were assessed. Although the lower doses (0.01-0.25 mg/kg) of alendronate did not influence plasma Ca, the high doses (1.25-6.25 mg/kg) significantly decreased plasma Ca by the third day after single iv administration. In these groups, urinary Ca excretion did not show any significant change, but urinary Pyr and D-Pyr excretion decreased significantly at high doses. The hypocalcemic effect lasted for only 1 or 2 days (2-3 days after injection) even at high doses of alendronate. In the group receiving elcatonin (8.0 U/kg, twice daily), a significant decrease in plasma Ca was evident as early as 1 day after the start of administration. This was accompanied by a marked increase in urinary Ca excretion in the early stage without a significant decrease in urinary Pyr or D-Pyr excretion, and the suppression of bone resorption was more pronounced in the late phase of treatment with elcatonin. These results suggest that alendronate decreases plasma Ca chiefly by suppressing bone resorption, whereas elcatonin decreases plasma Ca by inhibiting bone resorption and accelerating Ca excretion. The present data show that both alendronate and elcatonin inhibit bone resorption and exert an antihypercalcemic effect, but the mechanism of action is different in the two drugs.

Alendronate↗
PubMed1996

Isolation and identification of compounds from Brazilian propolis which enhance macrophage spreading and mobility.

Brazilian propolis is known to induce the activation of murine effector cells. We isolated and identified six compounds from a water-soluble extract of Brazilian propolis, all of which have enhancing effects on the spreading and mobility of murine macrophages. These compounds were identified as caffeoylquinic acid-derivatives, namely, 5-caffeoylquinic acid (1), chlorogenic acid (2), 4-caffeoylquinic acid (3), 4,5-dicaffeoylquinic acid (4), 3,5-dicaffeoylquinic acid (5) and 3,4-dicaffeoylquinic acid (6).

Animals↗
PubMed1996

The mode of inhibitory action of alpha-mangostin, a novel inhibitor, on the sarcoplasmic reticulum Ca(2+)-pumping ATPase from rabbit skeletal muscle.

alpha-Mangostin, the principal ingredient of the fruit hull of Garcinia mangostana, caused a concentration-dependent decrease in the activities of both Ca(2+)-ATPase and Ca(2+)-transport of the sarcoplasmic reticulum from rabbit skeletal muscle with an IC50 value of 5 microM. Neither Ca2+ release nor other enzyme activities were affected by alpha-mangostin. Kinetic analysis of the inhibitory effects of alpha-mangostin on Ca(2+)-ATPase suggests that the inhibition of the ATPase is a noncompetitive-type with respect to ATP or Ca2+. alpha-Mangostin may become a useful pharmacological tool for clarifying the physiological functions of Ca(2+)-pumping ATPase and sarcoplasmic reticulum.

Adenosine Triphosphate↗
PubMed1996

Effect of dietary L-glutamine on the hepatotoxic action of D-galactosamine in rats.

The protective effect of dietary L-glutamine against the hepatotoxic action of D-galactosamine (GaIN) was investigated by model experiments with rats. Rats fed with 20% casein diets containing 10% free amino acids were injected with GaIN, and the serum aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase activities and the hepatic glycogen content were assayed 20 hours after the injection. These enzyme activities in the group fed with 10% L-glutamine diet for 8 days were lower than those in the groups fed with the control, 10% L-glutamic acid and 10% L-alanine diets for 8 days. The more prolonged the feeding period with the 10% L-glutamine diet was, the more the serum activity levels of such enzymes were decreased. Although neomycin also lowered these enzyme activities, its simultaneous ingestion with neomycin did not show any additive or synergistic effect. The hepatic glycogen content in the 10% glutamine group still remained high after the GaIN treatment. It is therefore assumed that the effectiveness of glutamine intake would have been mediated by glycogen metabolism rather than by uridine metabolism.

Alanine↗
PubMed1996

Effects of dietary gluten on the hepatotoxic action of galactosamine and/or endotoxin in rats.

This study was done to clarify the effects of dietary wheat gluten on the hepatotoxic action of D-galactosamine (GalN) and endotoxin (Etx). Male Wistar rats fed a high casein or high gluten (supplemented with L-Lys and L-Thr) diet were injected with GalN or Etx, and the plasma glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and lactase dehydrogenase activities were examined 20 h later. In rats fed the high gluten diet, these enzyme activities were lower than in the high casein group after injection of 800 mg/kg of GalN. But such a difference between the casein and gluten groups was not clear when they were treated with 400 mg/kg of GalN nor observed even after injection of Etx or Etx+GalN (400 mg/kg). Similarly these was no difference in the plasma concentrations of Etx, tumor necrosis factor-alpha, or interferon-gamma in the rats receiving an injection of 800 mg/kg of GalN between both dietary groups. These results suggest that dietary gluten affords protection against hepatic injury by a high dose of GalN but not by a low dose of GalN and/or Etx.

Alanine Transaminase↗
PubMed1996

Changes in cerebral oxygenation and hemodynamics during obstructive sleep apneas.

OBJECTIVE: To evaluate changes in cerebral tissue oxygenation and blood volume during obstructive sleep apnea (OSA). METHODS: We studied eight men with moderate to severe OSA by near-infrared spectroscopy (NIRS) simultaneously with polysomnography during nocturnal sleep (five patients) and daytime naps (three). RESULTS: In all patients, a consistent decrease of oxyhemoglobin (OxyHb) and increases of deoxyhemoglobin and total hemoglobin (TotalHb) in the regional cerebral tissue were observed during the episode of OSA at every sleep stage. Changes in each hemoglobin and apnea duration were significantly (p<0.01) more remarkable during rapid eye movement (REM) sleep than non-REM (NREM) sleep. Significant correlations of changes in OxyHb and TotalHb during the apneic episode with apnea duration were found during both NREM and REM sleep (p<0.01). CONCLUSIONS: Since TotalHb is used as an indicator of blood volume in the NIRS technique and the venous return is reported to increase during OSA, it is assumed that cerebral blood flow (CBF) increases during the episode of OSA. Because a decrease in OxyHb was observed and brain activity is reported to decrease during OSA, it is supposed that oxygen supply to the brain tissue decreases rather than oxygen consumption in the brain increases. The results of this study indicate that possibly increased CBF could not compensate for reduced arterial oxygen saturation and cerebral tissue hypoxia may occur during the episode of OSA.

Adult↗