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Biomedical subjects

A Tamura

Publications and source records attributed to A Tamura.

At least 559 records · Page 31Linked to original sources
PubMedDate not supplied

Affinity purification of fusion chaperonin Cpn60-(His)(6) from thermophilic bacterium Bacillus strain MS and its use in facilitating protein refolding and preventing heat denaturation.

The cpn60 gene from Bacillus strain MS, which is highly homologous to Bacillus stearothermophilus, was cloned. Cpn60 with a hexahistidine affinity tag (His)(6) fused to its C-terminus (cpn60-(His)(6)) was overproduced in Escherichia coli. Cpn60-(His)(6) was expressed in a soluble form in E. coli. and purified to homogeneity in a single step by nickel chelate affinity chromatography. Cpn60-(His)(6) formed a tetradecamer and had ATPase activity. Cpn60-(His)(6) mediated refolding of guanidine hydrochloride unfolded pig heart malic dehydrogenase (MDH) and Thermus flavus MDH at 25 and 70 degrees C, respectively, in an ATP-dependent manner. In addition, cpn60-(His)(6) prevented heat denaturation of pig heart MDH and T. flavus MDH at 30 and 80 degrees C, respectively, in an ATP-dependent manner. Therefore, cpn60-(His)(6) facilitates protein refolding and prevents heat denaturation of proteins across a wide temperature range.

Bacillus↗
PubMedDate not supplied

Protection from cerebral ischemia by a new imidazole derivative (Y-9179) and pentobarbital. A comparative study in chronic middle cerebral artery occlusion in cats.

For the purpose of investigating the protective action against cerebral ischemia by a new imidazole derivative (Y-9179) and pentobarbital, regional cerebral ischemia was produced in 53 cats by permanent occlusion of the middle cerebral artery (MCA) via the transorbital approach. In 20 cats, the clips were applied at the origin of the right MCA whereas in the remaining 33 they were applied laterally. The administration of Y-9179 (6.25 and 12.5 mg/kg/day), pentobarbital (25 mg/kg/day) and saline was started 30 min after MCA occlusion and continued for 3 days. The cats were observed for 7 days and then sacrificed. Since there was a remarkable difference in mortality between the medial (65%) and the lateral occlusion groups (15%), the evaluation of drug effects was based only on the results obtained with the lateral occlusion group. The brains were sliced at 4 fixed coronal planes, in which the ratios of the infarcted area in the 2 hemispheres were obtained by planimetry. A statistically significant decrease in the infarction rate was found both in Y-9179 and pentobarbital-treated groups compared to the control group. Since the CNS depressant action of Y-9179 is far less potent than that of pentobarbital, the present results indicate the potential usefulness of Y-9179 in the management of strokes.

Animals↗
PubMedDate not supplied

Correlation between rCBF and histological changes following temporary middle cerebral artery occlusion.

Correlations between changes in regional, cortical, cerebral blood flow (rCBF) and histological changes in the corresponding brain regions were examined following middle cerebral arterial occlusion in 24 cats. In all animals, the duration of arterial occlusion was 2 hours followed by 2 hours of recirculation. The animals were divided into 2 groups according to the severity of the observed histological damage. Severe cortical damage was observed in 8 cats (Group A), and, in the remaining 16 cats, little or no cortical damage was seen (Group B). There was a statistically significant difference between these 2 groups in the average rCBF values during ischemia. During recirculation, there was a prompt and uniform recovery of rCBF in animals in group B but a marked diversity; of rCBF ranging from hyperemia to oligemia in animals in group A. This diversity of rCBF reflects inhomogenous blood flow. This study indicates potential hazards for surgical revascularization in the aute stage of stroke when brain damage has progressed beyond a certain level.

Animals↗
PubMedDate not supplied

Computed tomographic measurement of local cerebral blood flow by xenon enhancement.

The present technique was developed to overcome some of the disadvantages of measuring cerebral blood flow by radionuclide methods, such as poor localization of flow values and errors that result if the brain is pathological and local partition coefficients are altered. Serial CT scanning in humans was carried out during and after inhalation of 50 to 70% non-radioactive xenon. This diffusible gas with high atomic number enhanced gray matter first by 19 +/- 4 Hounsfield Units (HU) and later white matter by 24 +/- 4 HU. The regionality of flow values were cursored on CT pictures with a high spatial resolution of 4 X 4 mm (64 pixels) or 0.16cm2 X 0.5cm. In seven normal subjects, blood flow in gray matter was 82 +/- 11 ml/100gm/min and that in white matter 24 +/- 5ml/100gm/min. The partition coefficient (lambda), which is not obtainable in vivo by radionuclide scanning, was 0.9 +/- 0.1 for normal gray matter, 1.4 +/- 0.2 for normal white matter. Reduced flow, 13% in gray matter and 46% in white matter, was found in a large infarct secondary to complete occlusion of middle cerebral artery. In edematous tissue, blood flow was not significantly impaired in gray matter but was reduced to 29 to 54% in white matter. Local lambda values were reduced to 0.6-0.9 in edematous tissue, and 0.3-0.7 in infarction. This method appears to have several advantages over conventional isotope methods of measuring cerebral blood flow and provides useful clinical and research information.

Adult↗
PubMedDate not supplied

A reversible type of neuronal injury following ischemia in the gerbil hippocampus.

The Mongolian gerbil is known to develop delayed neuronal death in the hippocampus following brief forebrain ischemia (Brain Res 239: 57-69, 1982). The effect of pentobarbital on this slow process of neuronal damage was examined. Immediately following 5 min of bilateral carotid occlusion, pentobarbital (10, 20, or 40 mg/kg) was injected. The control animals received saline injection. Seven days following ischemic insult, animals were perfusion-fixed and the neuronal density in the hippocampal CA1 subfield was counted. Most of the neurons in the CA1 sector survived ischemic insult when pentobarbital was given, whereas most of control group neurons were lost without the treatment. The average neuronal density of 20 mg/kg group was 168.2 +/- 12.3 (SEM) per 1 mm linear length of the CA1 subfield. The density in 40 mg/kg group was 181.1 +/- 14.9. The neuronal density in the whole control group was 34.3 +/- 5.1. The density of unoperated normal gerbils was 212.3 +/- 3.9. This result indicates that the neuronal damage of "delayed neuronal death" is reversible. On the other hand, when pentobarbital was injected 1 hr following ischemia, it showed no effect. The cell change in the CA1 sector, reversible at the initial stage, seems to rapidly become irreversible, while neurons still remain intact morphologically.

Animals↗
PubMedDate not supplied

Successful coronary angioplasty for the remaining coronary artery with two completely occluded arteries with prior bypass grafting.

A 61-year-old man underwent coronary artery bypass grafting because of severe three-vessel disease. Since he had post-operative anginal attacks, coronary angiography was performed. The examination revealed the right coronary artery (RCA) and left circumflex artery (LCX) to be completely occluded, and the left anterior descending artery (LAD) showed 90% stenosis. Furthermore, the three bypass grafts (to RCA, LCX and LAD) were all occluded. The patient had severe anginal episodes despite drug therapy. Since the patient refused a second bypass operation, we performed percutaneous transluminal coronary angioplasty on the LAD. Subsequently, the stenosis of LAD was reduced to 25%, eliminating subjective episodes of angina pectoris.

Angioplasty, Balloon↗
PubMedDate not supplied

Induction of apoptosis by dopamine in human oral tumor cell lines.

Dopamine dose-dependently reduced the viable cell number of both human salivary gland tumor HSG and oral squamous cell carcinoma HSC-2, HSC-4, and NA cells. CoCl2 significantly reduced both the cytotoxic activity and radical intensity of dopamine (determined by ESR spectroscopy). Dopamine produced DNA fragments (demonstrated by TUNEL method) and induced degradation of cytokeratin by activated caspase in HSG cells (detected by an immunocytochemical method, using a specific M30 monoclonal antibody). FACS analysis demonstrated that dopamine induced DNA fragmentation, a biochemical hallmark of apoptosis, in human promyelocytic leukemia HL-60 cells. The addition of catalase did not prevent the apoptosis-inducing activity of dopamine, reducing the possibility of the involvement of H2O2 for dopamine-induced apoptosis. Dopamine transiently induced p38 mitogen-activated protein kinase (MAP kinase) phosphorylation. However, an inhibitor of p38 MAP kinase phosphorylation, SB203680, failed to inhibit the dopamine-induced apoptosis. These data suggest that p38 phosphorylation at an early stage may not be a causative event for apoptosis.

Apoptosis↗
PubMedDate not supplied

Positive and negative oral contrast agents for combined abdominal and pelvic helical CT: first iodinated agent and second water.

Combined abdominal and pelvic helical computed tomography (CT) with intravenous contrast media was performed on 19 patients with 400 mL of diluted iodine solution 60 minutes before and 400 mL of water just before CT. The distal small bowel was opacified by the positive contrast agent, and the stomach by the negative contrast agent in all patients. The gastric contents were homogenous, and the density was a mean +/- standard deviation 2.5+/-7.3 HU. The difference between the densities of the gastric contents and of the gastric wall (mean +/- s.d. 80.8+/-20.9 HU) was statistically significant (p<.05). There were no pseudotumors. Thus our protocol, first diluted iodine solution and second water, can be used as a method for the oral administration of contrast agents for combined abdominal and pelvic helical CT with intravenous contrast media.

Administration, Oral↗
PubMedDate not supplied

Pedunculated verrucous carcinoma of the thigh.

Verrucous carcinoma, a variant of squamous cell carcinoma, is distinct from squamous cell carcinoma in morphology and behavior. We report an unusual case of a large pedunculated verrucous carcinoma on the right thigh of a 73-year-old male without any preceding skin lesion. Histologic examination revealed a cauliflower-like tumor consisting of deeply invaginated epidermal proliferation, and the intact basement membrane. To our knowledge the "pedunculated" cutaneous verrucous carcinoma has not been previously reported.

Aged↗
PubMedDate not supplied

Invasive squamous cell carcinoma arising from verrucous carcinoma. Recognition of verrucous carcinoma of skin as an in situ carcinoma.

In 1948, Ackerman first coined the term "verrucous carcinoma" to describe a variant of well-differentiated squamous cell carcinomas of the oral cavity. Similar lesions of the skin, other mucosa or mucocutaneous regions were subsequently reported. To date, verrucous carcinoma has been considered to be a variant of well-differentiated squamous cell carcinoma, which sometimes shows invasive changes but rarely metastasizes. In this study, findings for 3 patients with verrucous carcinomas in which foci of invasive squamous cell carcinoma existed are presented. Furthermore, the clinical features of 9 patients with verrucous carcinoma of the skin observed in our hospital between 1990 and 2004 are summarized. Lesions were located on the face, trunk or extremities. Foci of invasive squamous cell carcinoma were found in 30% of verrucous carcinomas, almost equal to the reported rate of verrucous carcinoma in oral or penile regions. Verrucous carcinoma of the skin should be recognized as a unique subtype of in situ carcinomas, which show exophytic nodular growth and are potentially malignant.

Adult↗
PubMedDate not supplied

Effects of indeloxazine hydrochloride on behavioral and biochemical changes in the chronic phase of focal cerebral ischemia in rats.

The effects of a new cerebral activator, indeloxazine hydrochloride, on behavioral, electroencephalographic and biochemical changes were investigated during the chronic phase in rats subjected to left middle cerebral artery occlusion. Disturbance of the one-trial passive avoidance task and neurological deficits were present for 14 days after middle cerebral artery occlusion, while no significant changes in spontaneous motor activity and electroencephalogram in the cerebral cortex were observed. Significant decreases in the content of serotonin and norepinephrine in the frontal cortex, of norepinephrine and 3-methoxy-4-hydroxy-phenylethylglycol in the hippocampus, and of 3-methoxy-4-hydroxy-phenylethylglycol in the corpus striatum on the occluded side were observed on day 14 after surgery. Oral administration of the test drug was started from day 7 after surgery and was repeated once a day for 8 days. Indeloxazine (10 or 20 mg/kg) significantly prolonged the latency of step-through in the passive avoidance test and desynchronized the spontaneous electroencephalogram without affecting neurological deficits. Indeloxazine (10 or 30 mg/kg) caused significant increases in serotonin and decreases of 5-hydroxy-indoleacetic acid in the bilateral frontal cortex and hippocampus and contralateral corpus striatum. Indeloxazine (30 mg/kg) increased norepinephrine in the contralateral frontal cortex and bilateral hippocampus and decreased 3-methoxy-4-hydroxy-phenylethylglycol in the contralateral hippocampus. Thus, we found that indeloxazine ameliorated cerebral function in the chronic ischemic model. From the present results, it is suggested that the pharmacological action of indeloxazine may be attributable to its enhancing action on central monoaminergic systems.

Animals↗
PubMedDate not supplied

Application of reconstruction computed tomography in a case of tuber cinereum hamartoma.

A case of a 2-year-old girl with tuber cinereum hamartoma is evaluated by computed tomography (CT). Special reference is made to the application of CT image reconstruction, which has not yet been reported in the literature. The location, extent, shape and size of the mass lesion and also the anatomical relationship to adjacent structures are clearly demonstrated in sagittal and coronal CT images reconstructed from serial thin-section CT images in conjunction with target imaging and a review program.

Child, Preschool↗