Biomedical subjects

T Orita

Publications and source records attributed to T Orita.

96 records · Page 6Linked to original sources

PubMedDate not supplied

Construction of a plasmid vector for the regulatable high level expression of eukaryotic genes in Escherichia coli: an application to overproduction of chicken lysozyme.

A novel expression vector pKP1500 for synthesizing unfused protein in Escherichia coli was constructed. pKP1500 perserves the tac promoter, the lacZ SD sequence, unique restriction sites (EcoRI, SmaI, BamHI, SalI, PstI and HindIII) and the rrnB terminators of pKK223-3, but the replication origin is replaced with that of pUC9. Construction of this plasmid is based upon the observation that the copy number control of pUC9 is temperature dependent. At 28 degrees C, the copy number of pKP1500 is less than 25 per chromosome, approximately the same copy number as that of pKK223-3, which contains the replication origin of pBR322, whereas at 42 degrees C, the copy number increases about 10 times and reaches up to 230 copies per chromosome. The main advantage of this system is that the temperature-dependent copy control and regulatable expression of the tac promoter make cells carrying pKP1500 derivatives stable against selective pressure by detrimental overproduction of foreign proteins at a low temperature and permits high expression of cloned DNAs at a high temperature. When chicken lysozyme cDNA carrying the initiation codon (ATG) immediately upstream from the Lys1 codon was inserted downstream from the tac promoter and the SD sequence, the pKP1500 derivative produced lysozyme at about 25% of the total cellular proteins. This value is more than 10 times higher than that obtained with the pKK223-3 derivative carrying the same lysozyme cDNA. By comparison, the expression of eukaryotic genes from the tac promoter reported by others has usually been less than a few % of the total cellular protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Coronal MR imaging for visualization of wallerian degeneration of the pyramidal tract.

A coronal image taken along a straight line between the front edge of the medulla and the deepest point of the interpeduncular cistern clearly displayed wallerian degeneration of the segment of the pyramidal tract between the internal capsule and the pons, the medulla, or the decussation. This visualization was verified in 21 patients with moderate or severe hemiparesis following a stroke episode.

Adult↗

PubMedDate not supplied

Early, evolving Wallerian degeneration of the pyramidal tract in cerebrovascular diseases: MR study.

OBJECTIVE: The purpose of this study was to demonstrate the early features of the Wallerian degenerative process and their relationship with the severity of motor deficit. MATERIALS AND METHODS: Fourteen patients with infarction or hemorrhage of the basal ganglia were studied by MRI of the same coronal slice along the pyramidal line. RESULTS: The earliest sign of abnormal signal intensity was detected 0.7 month after the initial insult. On proton-density (PD) imaging, low signal intensity was observed on 11 (73.3%) of 15 occasions from 0.7 to 2.0 months, and abnormal signal intensity was not detected 5 (83.3%) of 6 times from 2.1 to 3.7 months. High signal intensity was revealed on 11 (78.6%) of 14 occasions after 3.8 months. The widest extent of the low-intensity signal band on PD imaging was closely related to the severity of motor deficits at > 4 months. CONCLUSION: The development of the Wallerian degenerative process was divided into four stages by MRI. We conclude that the extent of Wallerian degeneration is related to the severity of motor deficit.

Adult↗

PubMedDate not supplied

Meningioma with extensive vacuolization--a contribution to the pathogenesis of intratumoral cyst formation.

Seven cases of meningioma with extensive vacuolization are reported. Upon plain CT, two cases appeared as diffuse hypodense masses, while two cases were mixed-density masses consisting of iso-dense and low-density components. A diffuse marked enhancement effect was seen in three cases and a thin ring enhancement effect appeared in one case. In four of these cases, macroscopic cysts were observed. It is suggested that the formation of macroscopic cysts or microscopic vacuoles mimics the developmental process of the subarachnoid space in the embryo. A review of the literature on this phenomenon is presented.

Adult↗

PubMedDate not supplied

Measurement of labeling index of DNA polymerase alpha in human brain tumors. Comparative study with labeling indices of BUdR in vitro and Ki-67.

Proliferative activity of 28 human brain tumors was estimated by simultaneous measurement of DNA polymerase alpha, Ki-67 and bromodeoxyuridine (BUdR) labeling indices on microscopic tissue preparations stained immunologically with monoclonal antibodies using a peroxidase technique. All the antigens were exclusively found in the nucleus. The labeling index of BUdR was lower than those of the other indicators. The values of the DNA polymerase alpha labeling index were almost the same as those of the Ki-67 labeling index. Simultaneous measurement of these parameters may provide more useful information on tumor cell growth kinetics than that of a single parameter.

Adolescent↗

PubMedDate not supplied

Comparative study of the effects of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor on generation and mobilization of neutrophils in cyclophosphamide-treated neutropenic mice.

To examine the differential in vivo effects of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on the recovery from neutropenia caused by chemotherapy, we directly compared the actions of these CSFs on neutrophil count in the bone marrow, spleen, and peripheral blood of mice treated with an anticancer drug, cyclophosphamide (CPA). Both G-CSF and GM-CSF stimulated the generation of neutrophils in bone marrow, but GM-CSF is only about 1/20 as effective as G-CSF. Both CSFs also stimulated the release of the generated neutrophils therefrom. G-CSF mobilized the neutrophils into both the circulation pool and the marginal pool, and these neutrophils were able to migrate into the inflammatory site when stimulated by casein. On the other hand, GM-CSF mobilize the neutrophils into the marginal pool but not the circulation pool, and they were not able to migrate into the inflammatory site. These findings indicate that G-CSF physiologically plays an important role as a factor which stimulates neutrophil mobilization from bone marrow into circulation as well as neutrophil generation in the bone marrow.

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