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Biomedical subjects

Y Tamura

Publications and source records attributed to Y Tamura.

At least 289 records · Page 16Linked to original sources
PubMed1995

Production of monoclonal antibody against the C1 component of rat estramustine-binding protein: immunohistochemical study of rat prostate.

The monoclonal antibody against estramustine-binding protein (EMBP) was produced by immunizing a mouse with EMBP antigen purified from rat ventral prostate. On western blotting analysis this antibody recognized the EMBP C1 component, and in an absorption test it recognized the EMBP antigen. Immunohistochemically, this antibody revealed positive staining for the ventral and dorsolateral prostate. In the epithelium of the ventral prostate, intense immunostaining was observed in the intraluminal secretory product; however, in the epithelium of the dorsolateral prostate, the staining was intense in the cytoplasm of the epithelial cells. These findings suggested differences of EMBP localization in the ventral and the dorsolateral prostate. Since the intensity of immunostaining for EMBP was decreased in the prostate of castrated rats, we considered that this antibody reflected the androgen dependency of EMBP.

Animals↗
PubMed1995

Chromosomal translocations in two feline T-cell lymphomas.

Two feline malignant lymphoma cell lines, FT-1 and FT-G, established from cats naturally infected with the feline leukemia virus were analyzed for chromosomal aberrations. Both FT-1 and FT-G cells had a modal number of 38 which is the normal diploid (2n) chromosome number of the domestic cat. G-banding-analysis showed that FT-1 had a translocation involving the short arms of chromosome A2 and D3--t (A2;D3) (p-;p+), and FT-G had a translocation involving the short arms of chromosomes A2 and B2--t (A2;B2) (p-;p+). Our data suggest that the chromosomal translocations were closely associated with the tumorigenesis in malignant lymphoma in cats.

Animals↗
PubMed1995

Effects of aluminum adjuvant on systemic reactions of lipopolysaccharides in swine.

In vivo effects of aluminum adjuvant on systemic reaction of bacterial lipopolysaccharide (LPS) in piglets were investigated. Intramuscular injection of 0.1 mg kg-1 of LPS added to aluminum hydroxide gel (LPS(+)AL) mitigated the leukopenia, trembling and serum levels of TNF-alpha and cortisol compared with the injection of LPS suspended in LPS-free saline (LPS(+)SALINE). The serum endotoxin levels were reduced remarkably but relatively long-lasting in the LPS(+)AL. The lethality in mice injected with LPS added to aluminum hydroxide gel was significantly reduced. Likewise, the Limulus activity of a test LPS was reduced by the addition of aluminum hydroxide gel or aluminum chloride.

Adjuvants, Immunologic↗
PubMed1995

Evaluation of the effects of esophageal varicosclerosants on local vascular occlusion and systemic blood coagulation.

The efficacy and safety of the various sclerosants available for esophageal sclerotherapy have not been adequately investigated. In the present study, we experimentally evaluated the effects on local vascular occlusion and systemic blood coagulation of five sclerosants: 5% ethanolamine oleate, 99.5% ethanol, 2% aethoxysclerol, thrombin, and n-butyl-2-cyanoacrylate. The effects were tested after injection into the auricular vein of rabbits. Prothrombin time, activated partial thromboplastin time, plasma fibrinogen level, and peripheral blood platelet count were measured before injection and 5 minutes, 1 hour, 1 day, and 7 days later. Histologic examinations were then made of the auricular vein, lungs, liver, spleen, and kidneys. In the initial period after injection of ethanol or thrombin, fibrinogen level and platelet count were significantly reduced. Except for thrombin, none of the drugs affected prothrombin time or partial thromboplastin time. Local thrombosis took place after the injection of ethanolamine oleate, ethanol, and aethoxysclerol, whereas thrombin injection did not result in local thrombosis or vascular occlusion. Cyanoacrylate produced no local thrombus formation but caused vascular occlusion. Over-dosing of thrombin and ethanol led to sudden death of animals. These findings suggest that it is necessary to assess further the safety of intravascular use of thrombin, that the other drugs seem to be usable, and that careful consideration should be given to the excess use of ethanol in clinical settings. The present animal model may be useful for evaluating various sclerosants, although findings may not be applicable to humans because of differences in vascular size.

Animals↗
PubMed1995

In-vivo induction of apoptosis in murine lymphocytes by bacterial lipopolysaccharides.

The effect of bacterial lipopolysaccharide (LPS) on the lymphoid organs in C3H/HeN and C3H/HeJ mice was investigated. In C3H/HeN mice, LPS induced apoptosis, characterised by morphological nuclear condensation and DNA fragmentation resulting in thymic atrophy. Similar but less severe changes were also observed in the spleen and lymph nodes. In C3H/HeJ mice, only a slight depletion of lymphocyte numbers was observed in the lymphoid organs. The plasma endotoxin levels were dependent on the LPS dose regardless of mouse strain. On the other hand, the plasma TNF-alpha levels were significantly elevated in C3H/HeN mice 1 h post-injection and the time course of plasma corticosterone concentration correlated well with the development of apoptosis. These findings suggest that TNF-alpha and corticosterone may play an important role in LPS-induced apoptosis of lymphocytes.

Animals↗
PubMed1995

Reversible expression of motility and flagella in Clostridium chauvoei and their relationship to virulence.

Clostridium chauvoei strain Okinawa produced spontaneous non-motile variants at an unusually high rate (approx. 10(-4) per generation) under normal conditions without mutagen. Revertants of non-motile variants were detected at a rate of approximately 10(-3). Biochemically, every variant corresponded well with the parental strain. By transmission electron microscopy, three of nine non-motile variants of strain Okinawa were found to be flagellate, while the other six were found to be aflagellate. These phenotypes were confirmed by Western blot analysis using monoclonal antibodies directed against the flagella of C. chauvoei. Moreover, the parental flagellate strain and non-motile flagellate variants were significantly more virulent in mice than non-motile, aflagellate variants. Our results demonstrated that phase variation in motility and flagellation occurs in C. chauvoei, and that the flagella are associated with the full expression of virulence.

Animals↗
PubMed1995

Influence of the muscle tension on the masseteric silent period in children and adults.

Three subject groups who have shown different biting forces were examined in order to investigate whether the physiological phenomenon that the duration of the silent period (SPD) of the masseter muscle would be influenced by background activities of the muscles. They were classified into child (CN, n = 10) and adult groups; the adult group was then further subdivided according to the strength of maximum biting force into a normal group (AN, n = 10) and a low biting force group with some symptoms (AS, n = 5). SPD was observed in the masseter muscles by applying chin tap stimulations during both clenching teeth (10%, 50% and maximum) and biting on a transducer (50 N, 100 N and maximum). With increase of muscle activities, SPD was significantly decreased in the AN and CN groups, whereas no significant changes were found in the AS group. When comparing SPDs among the three groups at the same voluntary effort, the AN group exhibited the shortest SPD followed by the CN and AS groups. The results suggest that SPD was positively influenced by the strength of the background activities of the muscles and that immaturity of the masseters in terms of muscle activity could affect the SPD.

Adult↗
PubMed1995

Lipopolysaccharide-induced apoptosis in swine lymphocytes in vivo.

The in vivo effects of bacterial lipopolysaccharide (LPS) on the immune systems of piglets were investigated. Intravenous injection of 0.5 mg of LPS per kilogram of body weight induced apoptosis, which was characterized by nuclear chromatin condensation and fragmentation and a ladder formation of nucleosomal DNA in lymphocytes both in the cortex of the thymus and in the germinal centers and paracortical areas of mesenteric lymph nodes at 24 h postinjection. The levels of endotoxin, tumor necrosis factor alpha, and cortisol in serum increased, generally according to the dose of LPS. These findings suggest that LPS can induce in vivo apoptosis of lymphocytes in piglets and support the notion that cytokine and endocrine responses may play an important role in LPS-induced apoptosis in the immune system.

Animals↗
PubMed1995

Inactivation of blasticidin S by Bacillus cereus. V. Purification and characterization of blasticidin S-deaminase mediated by a plasmid from blasticidin S resistant Bacillus cereus K55-S1.

Blasticidin S (BS) deaminase (BSR) from a BS-resistant strain, Bacillus cereus K55-S1, was purified to homogeneity. Molecular weights determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and by gel filtration on HPLC are about 15500 and 35000, respectively, indicating the enzyme is a homodimer. The amino acid composition and N-terminal sequence of BSR are the same as those deduced from the nucleotide sequence of the BS-resistant gene, bsr. The optimum temperature and pH for enzyme activity are 60-65 degrees C and near 10.0, respectively. The activity of BSR is inhibited by Cu2+, Hg2+, and p-chloromercuric benzoate (PCMB). Inhibition by PCMB or HgCl2 is reversible by the addition of SH reagents. The enzyme catalyzes the deamination of BS and its derivatives, but not cytosine nucleosides.

Aminohydrolases↗
PubMed1995

Correlation between isolated negative U waves and the grade of coronary artery spasm.

The relation between isolated negative U waves and the severity of induced coronary artery spasm was investigated in 24 patients with variant angina to determine the grade of myocardial ischemia during the appearance of isolated negative U waves. Coronary artery spasm was induced by injections of either incremental doses of acetylcholine or ergonovine into the left coronary artery. Coronary spasm was quantified into 4 grades: Grade 0 = complete perfusion, Grade 1 = partial perfusion, Grade 2 = penetration without perfusion, and Grade 3 = no perfusion. Induction with acetylcholine was discontinued when a coronary spasm of Grade > or = 2 was induced. Electrocardiogram in leads V1 to V6 and systemic blood pressure were recorded continuously. Provocations of coronary spasm with at least 2 doses of acetylcholine could be performed in 15 patients. All acetylcholine-induced coronary spasms of Grade < or = 1 disappeared spontaneously within 3 min. Negative U waves developed in 19 (79%) patients, in whom 37 trials with acetylcholine or ergonovine injection were performed. Isolated negative U waves were detected in 10 trials, negative U waves and ST depression in 8 trials, and negative U waves and ST elevation in 14 trials. The induced coronary spasms associated with isolated negative U waves were of Grade 1 in 9 of the 10 trials. In contrast, all of the coronary spasms associated with negative U waves and ST elevation had a Grade of > or = 2. In conclusion, the coronary angiographic finding associated with isolated negative U waves is coronary spasm with delayed filling of the distal coronary artery, with opacification of the entire coronary bed.

Acetylcholine↗
PubMed1995

Effects of oil adjuvant on systemic response to Escherichia coli lipopolysaccharide in swine.

Intramuscular injection of 0.1 mg/kg of Escherichia coli lipopolysaccharide (LPS) mixed with Freund's complete adjuvant (LPS+FCA) in piglets mitigated the leukopenia and TNF-alpha and cortisol levels in the serum compared with that of LPS suspended in LPS-free saline. The endotoxin level in the serum of the LPS+FCA was remarkably reduced. These results suggest that the addition of oil adjuvant mitigate the systemic toxicity of LPS.

Animals↗
PubMed1995

[Study on cadmium-induced metallothionein-like protein in bone marrow of rabbit].

It has been recognized that metallothionein (MT) is a low molecular-weight protein and can be induced by heavy metals in several organs. Most studies on MT focus on the liver and kidney, and little is known about MT in the bone marrow. In the present study, the characterization of the MT-like protein in bone marrow of rabbits was investigated after the injection of CdCl2. A dose of 8 x 10(-5) mol/kg CdCl2 was injected subcutaneously into Japanese White Rabbits (male, 3.5 kg) for five days. Twenty-four hours after the last CdCl2 injection, the bone marrow, liver and kidney were removed immediately and frozen. The fractions of metal-binding protein were obtained by gel filtration (Sephadex G-75) of cytosol from the tissues of Cd-treated rabbit. They were heat-stable and low molecular-weight (under 10 kDa) proteins. They had high absorption at 250 nm. These observations suggest that the injection of CdCl2 induced MT-like protein in bone marrow.

Animals↗
PubMed1995

Effect of modified LDL on the release of NO and PGI2 from rat peritoneal macrophages.

Nitric oxide (NO) and prostacyclin (PGI2) have vasodilative and anti-proliferative effects on smooth muscle cells (SMC) and an anti-aggregating action on platelets. The present study was designed to elucidate the influence of modified low density lipoprotein (LDL) on the release on NO and PGI2 from rat peritoneal macrophages. Cholesteryl ester (CE) content in macrophages markedly increased on incubation with acetylated LDL (ac-LDL), while NO release did not change. Although incubation with mildly oxidized LDL (m-ox-LDL) and highly oxidized LDL (h-ox-LDL) increased CE content in macrophages, only incubation with h-ox-LDL reduced NO release. PGI2 release from macrophages was not affected by incubation with ac-LDL, m-ox-LDL or h-ox-LDL. These results indicate that the degree of suppression of NO release in macrophages by modified LDL is related to the extent of oxidative modification of LDL itself, but not to the extent of the accumulation of CE in macrophages. Although the role of NO released from macrophages in atherosclerosis is still unclear, the observation of reduced production of NO from macrophages in response to ox-LDL may provide new insight into the role of ox-LDL in the pathogenesis of atherosclerosis.

Animals↗
PubMed1995

[A case of advanced gastric cancer successfully treated with combination chemotherapy using THP, 5'-DFUR and CDDP, followed by surgical resection].

We reported a patient with advanced gastric cancer and a liver metastasis, who responded remarkably to combination chemotherapy using THP, 5'-DFUR and CDDP. The patient was administered four courses of THP (15 mg/m2/day, on day 1, iv), 5'-DFUR (1400 mg/m2/day, on days 1-4 and 15-18, orally), and CDDP (80 mg/m2/day, on day 5, iv) every 4 weeks. As a result, both the primary and metastatic tumors decreased remarkably in size at more than 19 weeks (PR) and we performed curative total resection of the stomach and partial resection of the liver. Histologically, the effects of chemotherapy on gastric focus were evaluated as grade 1a and the liver metastasis completely disappeared. This combination therapy proved useful to treat advanced gastric cancer in this patient.

Adenocarcinoma↗
PubMed1995

Protective action of zinc against glutamate neurotoxicity in cultured retinal neurons.

PURPOSE: To examine the effects of Zn2+ on glutamate-induced neurotoxicity in cultured retinal neurons. METHODS: Primary cultures obtained from fetal rat retinas (16 to 19 days gestation) were used. The neurotoxic effects of excitatory amino acids were quantitatively assessed using the trypan blue exclusion method. RESULTS: A brief exposure of retinal cultures to glutamate or N-methyl-D-aspartate (NMDA) induced delayed cell death. Zn2+ at concentrations of 3 to 30 microM ameliorated glutamate- and NMDA-induced neurotoxicity in a dose-dependent manner. By contrast, neurotoxicity induced by a 1-hour exposure to kainate was not affected by Zn2+. CONCLUSIONS: These findings demonstrate that Zn2+ protects retinal neurons from NMDA receptor-mediated glutamate neurotoxicity.

Animals↗
PubMed1995

[Circularity index of left ventricular shape in the assessment of heart disease].

Left ventricular volume and ejection fraction obtained by cineangiography are useful to evaluate global left ventricular function in humans. Left ventriculography provides evidence of the effect of coronary artery stenosis on regional wall motion in patients with coronary artery disease. Changes in left ventricular shape are also found in various heart diseases. The left ventricular cavity is normally ellipsoid in shape, but becomes flat in hypertrophic cardiomyopathy, globular in dilated cardiomyopathy, and aneurysmal in some patients with myocardial infarction. This study developed a new method to quantify regional and global left ventricular shape. Regional circularity index (RCI) was defined as GD divided by r (GD = distance from each 5-degree endocardial margin to the center of gravity, r = radius of the circle equal to left ventricular area). The global circularity index (GCI) was derived from the sum of magnitude of RCI-1. The end-systolic GCI was related to end-systolic left ventricular wall stress (r = 0.71, p < 0.001). The change in GCI during systole was related to left ventricular ejection fraction (r = 0.79, p < 0.001). In severe cases of dilated cardiomyopathy, the left ventricle became more spherical during ejection. End-systolic left ventricular moment around the minor axis had a good correlation with left ventricular ejection fraction (r = 0.81, p < 0.001). Quantification of regional and global left ventricular shape can be used to estimate left ventricular wall stress from left ventricular shape. Left ventricular shape change during systole and the moment around the left ventricular short axis contributes to left ventricular ejection.

Angiocardiography↗
PubMed1995

Myocardial blood flow: comparison of oxygen-15-water bolus injection, slow infusion and oxygen-15-carbon dioxide slow inhalation.

UNLABELLED: This study investigates the most appropriate protocol for measuring regional myocardial blood flow (MBF) using 15O-water in clinical applications. METHODS: Regional MBF, perfusable tissue fraction (PTF) and arterial blood volume (Va) were measured using 15O-water and dynamic PET on five healthy volunteers based on previously published models. Calculated values were compared for the following three tracer administration protocols: 15O-water bolus injection, 15O-water slow (2 min) infusion and 15O-carbon dioxide slow (2 min) inhalation. For the two slow administration protocols, the three parameters MBF, PTF and Va were computed by fitting the model equations to the myocardial regional time-activity curve. For the bolus injection of 15O-water, only two parameters, MBF and PTF, were fitted by using a fixed Va value obtained by a carbon dioxide blood volume scan. RESULTS: All protocols provided consistent MBF values, and the calculated values were homogeneous throughout the whole myocardial segments for all subjects. PTF values were also homogeneous and consistent in the anterior and lateral wall regions, but were significantly greater in the septum (approximately 20%) when the slow 15O-carbon dioxide inhalation protocol was used. MBF and PTF values obtained from the bolus injection protocol showed the smallest intersubject and interregional variations. The simulation study also showed that the magnitude of error was smallest when the bolus injection protocol was employed. CONCLUSION: The data suggest that the 15O-water bolus injection protocol together with the two-parameter fitting procedure provides the most accurate results for MBF and PTF. However, it requires arterial cannulation and a separate carbon monoxide scan. For clinical studies, however, the 15O-water infusion protocol would be a good alternative, providing MBF and PTF results with an acceptable degree of accuracy and without the need for arterial cannulation.

Administration, Inhalation↗