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Biomedical subjects

T Orita

Publications and source records attributed to T Orita.

At least 37 records · Page 2Linked to original sources
PubMed1995

Exanthem subitum (roseola infantum) with vesicular lesions.

We report a 7-month-old boy who developed vesicular lesions during the course of exanthem subitum. Human herpesvirus-6 (HHV-6) DNA was detected both in the skin lesions and in the throat, by polymerase chain reaction. IgG and IgM antibodies against HHV-6 were 1:10 and < 1:10, respectively on the tenth day of the illness, and > 1:640 and 1:10 on the twenty-second day, respectively. These results suggest that this was primary HHV-6 infection.

Antibodies, Viral↗
PubMed1995

Design of a centrifugal blood pump with magnetic suspension.

A new concept blood pump, whose impeller is suspended by permanent magnets and a mechanical pivot without seals or ball bearings, is presented in this paper. The primary aim of the blood pump is an application to implantable artificial hearts. The prototype model is of a centrifugal type with a four-vaned semiopen impeller 50 mm in diameter. Since this mechanism has no seals or ball bearings, flow stagnation or heat generation that might cause blood cell denaturation is expected to be small. The results of performance testing for the prototype model 2 were satisfactory regarding pump head and efficiency. The radial-suspension magnets and the magnetic coupling were stable. As a result, the present mechanism has been verified to be a candidate applicable to implantable artificial hearts.

Biomechanical Phenomena↗
PubMed1995

Brain temperature before and after brain death.

Although there has been renewed interest in human brain temperature, very little information is available on the association between brain temperature and cerebral perfusion pressure. In this study, we measured brain, tympanic, and rectal temperatures, arterial blood pressure and intracranial pressure in a case of massive hemorrhage deteriorating to brain death, and showed for the first time that when cerebral perfusion pressure began to decrease markedly brain temperature fell rapidly. Rectal and tympanic temperatures were higher than brain temperatures during the period of very low cerebral perfusion pressure. Circadian change in temperature (high at day, low at night) was preserved during the period of brain death.

Body Temperature Regulation↗
PubMed1995

[Symptomatic Rathke's cleft cyst presenting with hyponatremia: a case report].

A case of symptomatic Rathke's cleft cyst, showing symptoms due to hyponatremia, is reported. The patient was a 68-year-old woman with complaints of vomiting, diarrhea and somnolence. She had severe hyponatremia (109 mEq/l). Magnetic resonance image showed a cystic mass in the intra- and suprasellar region. A right fronto-temporal craniotomy was performed and the cyst was partially resected through the pterional approach. The cyst compressed the chiasma and anterior hypothalamus upward. In the cyst, there was xanthomatous fluid and hematoma. On histopathological examination, the cyst epithelium was diagnosed as Rathke's cleft cyst with craniopharyngioma component. These findings suggested that rapid compression to the anterior hypothalamus by intracystic hemorrhage caused hyponatremia.

Aged↗
PubMed1994

Pyramidal tract Wallerian degeneration and correlated symptoms in stroke.

In order to reveal the precise degree of injury in the pyramidal tract after stroke, we studied 35 patients with motor deficit associated with cerebrovascular disease of the internal capsule using the T2-weighted coronal image along the 'pyramidal line'. According to the severity of the motor deficit, the patients were divided into three groups. The Wallerian index was calculated as: (area of Wallerian degeneration in the pons divided by area of the ipsilateral half of the pons) x 100. There were significant differences between the three groups. It is concluded that the area of Wallerian degeneration is related to the severity of motor deficit.

Adult↗
PubMed1994

Polypeptide and carbohydrate structure of recombinant human interleukin-6 produced in Chinese hamster ovary cells.

A glycosylated form of human interleukin 6 (hIL-6) has been produced in Chinese hamster ovary (CHO) cells transfected with a cDNA clone for human IL-6. Recombinant hIL-6 was purified from a culture supernatant of the transfected CHO cells, and used for structural characterization. The complete amino acid sequence, composed of 185 amino acid residues, was determined and is identical to that predicted from the cDNA sequence. However, a recombinant hIL-6 species lacking two amino acid residues (Ala-Pro) from the N-terminus was also found. Two disulfide bonds are formed, between Cys45 and Cys51 and between Cys74 and Cys84. Recombinant hIL-6 carries one O-linked carbohydrate chain, and Thr139 is fully O-glycosylated. A portion of recombinant hIL-6 protein carries one N-linked sialooligosaccharide chain, and the N-glycosylation occurs at Asn46. The structure of the N-linked sugar chains was estimated by a combination of sugar mapping and glycosidase digestion. The major structure of the N-linked sugar chain predicted was of a fucosylated biantennary or triantennary complex type. Fucosylated triantennary sugar chains with one or two N-acetyllactosaminyl repeats were also found. The structure of the O-linked sugar chain was determined by 500 mHz 1H-NMR to be NeuAc alpha 2-3Gal beta 1-3(NeuAc alpha 2-6) Gal-NAcol.

Amino Acid Sequence↗
PubMed1994

Distal posterior cerebral artery aneurysms--three case reports.

One case of an aneurysm in the P3 segment and two cases of aneurysms in the P4 segment of the posterior cerebral artery are described. The P3 aneurysm in a 60-year-old female and a P4 aneurysm in a 63-year-old male were clipped or coated via the occipital interhemispheric approach. The other P4 aneurysm in a 73-year-old female was clipped via a hematoma cavity. The occipital interhemispheric approach should be selected for small or large P3 aneurysms and for P4 aneurysms associated with slack brain, as brain retraction is minimal and the approach to the aneurysm is straightforward.

Aged↗
PubMed1994

[Shunting operation with the medos programmable valve shunt system].

We reviewed 13 patients with hydrocephalus of varied etiology and two patients with arachnoid cyst who underwent shunting operations using Medos programmable valve shunt system. This shunt system allows 18 pressure settings, ranging from 30 to 200mmH2O in 10mmH2O differentials, percutaneously. Following the shunting operation, the size of the ventricle or arachnoid cyst was reduced in all cases and the clinical symptoms improved in 14 cases. The valve pressure was reset during the postoperative course in all cases. In five cases, resetting was performed because of management of complications. In the others, it was performed to find the most appropriate valve pressure for each patient. Complications were subdural effusion (2 cases), chronic subdural hematoma (2 cases) and slit ventricle syndrome (1 case). Subdural effusion and slit ventricle syndrome were improved easily by resetting the valve pressure, but both cases of chronic subdural hematoma finally required surgical treatment. Artifacts in MR imaging and movement of the valve pressure by MR imaging were small and created no clinical problem. In cases 1 and 2, clinical symptoms and CT finding were improved by a change of 30mmH2O. In case 2, hydrocephalus with slight subdural effusion followed a good course with frequent change of the valve pressure. Accordingly, we consider the Medos system to be useful for a more thorough treatment of hydrocephalus and arachnoid cyst after shunting operations.

Adolescent↗
PubMed1993

Clinical evaluation of DNA index in human brain tumors.

We evaluated the DNA index values in 28 brain-tumor patients showing DNA aneuploidy on the DNA histogram obtained by flow cytometry. In 17 cases among them, the DNA index values were compared to BUdR labeling indices (BUdR-LI). Average DNA indices of individual tumor types were 1.89 +/- 0.10 (6 glioblastomas multiforme), 1.93 +/- 0.05 (4 anaplastic astrocytomas), 1.68 +/- 0.09 (3 malignant meningiomas), 1.24 +/- 0.03 (7 meningiomas), 1.19 +/- 0.05 (2 pituitary adenomas) and 1.86 +/- 0.24 (6 metastatic brain tumors). Slow-growing tumors such as meningioma and pituitary adenoma, had lower values than malignant tumors, except a case of a metastatic brain tumor. All malignant meningiomas had higher DNA index values than the other meningiomas. No difference was observed between the DNA index values of glioblastomas multiforme and anaplastic astrocytomas. DNA index values were correlated with BUdR-LI values (p < 0.05), and seven cases with low DNA index values (1.13-1.31) had low BUdR-LI values of less than 1%. Others with high DNA index values of 1.44 or more had high BUdR-LI values of 3.5% or more. These results suggest that high DNA index values is related to tumor malignancy, and despite the presence of some disparities, many slow-growing brain tumor has low DNA index values.

Adult↗
PubMed1993

Reduction of the leukemogenic potential of malignant murine leukemic cells by in vivo treatment with recombinant human granulocyte colony-stimulating factor.

We have investigated the effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration on the leukemogenic potential of L-103 murine leukemic cells. Leukemogenic potential was assessed by comparing the regression lines drawn between the number of inoculated leukemic spleen cells and the mean survival time (MST) of the syngeneic recipients. rhG-CSF injected 2.5 micrograms daily for 14 days reduced the leukemogenic potential of spleen cells of the leukemic mice to 1/200 of the control. This phenomenon was not observed with the leukemic spleen cells treated with r-murine granulocyte-macrophage (rmGM)-CSF in vivo. Cytochemical study indicated that morphologically identifiable blast cells were fewer in the rhG-CSF-treated leukemic spleen. Furthermore, leukemic cells in the rhG-CSF-treated spleen were less proliferative than the control in spite of having more clonogenic cells in the leukemic cell preparation. Cytogenetical analysis showed that chromosome abnormalities found in the original leukemic cells were not altered by rhG-CSF administrations. It also showed that the frequency of the abnormal karyotype was reduced in rhG-CSF-treated leukemic spleen (4/17) as compared with the control (8/8), indicating that the mitotic fraction was smaller in the rhG-CSF-treated leukemic cells. These findings indicate that in addition to the reduced number of leukemic cells in the spleen cell preparation, a reduction of the proliferative capacity of the original leukemic cells is involved in the reduction of leukemogenic potential of leukemic cells treated with rhG-CSF in vivo.

Animals↗
PubMed1993

[Effects of granulocyte-colony stimulating factor on hematogram examinations].

Effects of granulocyte-colony stimulating factor (G-CSF) on hemograms were studied in the leukopenic phase after chemotherapy on patients with solid malignant tumors and lymphocytic malignancies. The samples were from patients with solid malignant tumors (solid tumor group) and from those with lymphocytic malignancies (lymphocytic malignancy group). In the control group, the increase rate and the decrease rate of the white blood cell count were 1.48 and 0.67, respectively. With the administration of G-CSF, they were 4.99 and 0.29 in the malignant tumor group, and 11.83 and 0.19 changes beyond the range of physiologic fluctuations with the administration of G-CSF. In term of increasing rate, immature myeloid cells were increased more remarkably than mature neutrophil by administration of G-CSF, indicating that the target cells of G-CSF are immature cells, and the increase of immature cells is responsible for the increase of the whole white blood cell count. Though immature myeloid cells with atypical morphology were rarely detected in the solid tumor group, they were observed more frequently in the lymphocytic malignancy group. In this study, we stress that the information about the history of G-CSF administration is indispensable for quality control of hemogram examinations.

Female↗
PubMed1993

[Granulocyte-colony stimulating factor and clinical laboratory].

The effects of granulocyte-colony stimulating factor (G-CSF) on the white blood cell count and the morphology of peripheral white blood cells were studied during the period of leukocytopenia following chemotherapy in patients with non-hematological malignant tumors (solid tumor group) and those with lymphatic hematological diseases (lymphocytic malignancy group). Cell surface markers were also analyzed to evaluate the usefulness of G-CSF in peripheral stem cell transplantation. After G-CSF administration, the white blood cell count showed remarkable changes beyond the physiologic range; the increase and decrease were 5.0 times and 0.3 times previous values, respectively, in the solid tumor group, and 11.0 times and 0.2 times, respectively, in the lymphocytic malignancy group. Concerning the morphology of peripheral white blood cells, immature leukocytes increased markedly to 133.0 times the previous value. The frequency of immature cells with morphological abnormalities was 0.5 percent in the solid tumor group, but 1.6 percent in the lymphocytic malignancy group. These findings suggest that administering G-CSF affects precision control and microscopic findings in routine laboratory blood tests and that information about whether the patient was treated with G-CSF should be obtained from the clinical staff. A cell surface marker, c-kit, was analyzed to clarify whether stem cells useful for peripheral stem cell transplantation appear in peripheral blood after administration of G-CSF. The incidence of c-kit-positive cells was at 1-10% in 3 of 5 patients in the solid tumor group administered G-CSF and in all 6 patients in the lymphocytic malignancy group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Improvement in the heterogeneous N-termini and the defective N-glycosylation of human interleukin-6 by genetic engineering.

Recombinant human interleukin-6 (IL-6), expressed in Chinese hamster ovary cells, has heterogeneous N-termini of Ala1 and Val3, as does naturally occurring IL-6. This heterogeneity is thought to be caused by difficulty in cleavage of the signal sequence. To obtain homogeneous IL-6, Pro at -1 was exchanged for Ala by site-directed mutagenesis. Alternatively, the signal sequence was replaced with that of human granulocyte-colony-stimulating factor. In both cases, the IL-6 designed to start with Ala1 was still heterogeneous, while the IL-6 designed to start with Val3 showed a homogeneous N-terminus. It is suggested that the heterogeneity of the N-terminus is caused not only by the signal sequence, but also by the succeeding sequences of the mature protein. Only a portion of recombinant human IL-6 is N-glycosylated. Asn46, being exchanged for Gln by site-directed mutagenesis, was confirmed to be partially N-glycosylated. The defective N-glycosylation was assumed to be caused by interference or tension from a disulfide bond near the N-glycosylation site. To verify this hypothesis, the Cys45 and Cys51 forming the disulfide bond were exchanged for Ser. The N-glycosylated species became predominant upon this substitution, suggesting that formation of the disulfide bond is a cause of the defective N-glycosylation.

Amino Acid Sequence↗
PubMed1992

Glial fibrillary acidic protein (GFAP) expression and nucleolar organizer regions (NORs) in human gliomas.

The frequency of nucleolar organizer regions (NORs) in each glioma tissue and the relation between the expression of glial fibrillary acidic protein (GFAP) and the frequency of NORs was investigated. The number of Ag-NORs per cell for glioblastoma multiforme was significantly higher than that for anaplastic astrocytoma (P less than 0.05) and that for astrocytoma (P less than 0.01). The number of Ag-NORs per cell for GFAP-positive cells was significantly lower than that for GFAP-negative cells in each histopathological grade (P less than 0.01). Moreover, the linear relationship was demonstrated between the Ag-NORs numbers of GFAP-negative cells and bromodeoxyuridine (BUdR) labeling indices. From these results, it is concluded that many GFAP-positive glioma cells may have low growth potential in glioma tissue and GFAP-negative cells may have a close relation to cell proliferation. The combination of immunohistochemical and silver colloid staining is a useful method for investigating the biological characteristics of brain tumors.

Astrocytoma↗
PubMed1992

Malignant meningioma metastasizing through the cerebrospinal pathway.

A case of malignant meningioma metastasizing through the cerebrospinal pathway is presented. The primary tumor was a parasagittal malignant meningioma invading into the brain. The tumor seeded to the cerebellopontine angle cistern and thoracic spine after multiple operations. Although this type of tumor borders the CSF, metastasis through the cerebrospinal pathway is rare, and only 18 such cases have been reported (2, 3, 10, 12).

Brain Neoplasms↗
PubMed1992

[Effects of antibiotics on the dissociation of platelet adherence in pseudothrombocytopenia].

To elucidate the effects of antibiotics on platelet adherence phenomena, we examined dissociation of platelet adherence in EDTA-dependent pseudothrombocytopenia by adding Kanamycin or Colimycin. We found the rapid dissociation of platelet adherence caused by addition of Kanamycin (20 mg) or Colimycin (20 mg) in 1 ml of EDTA-anticoagulated blood from patients with EDTA-dependent pseudothrombocytopenia. This dissociation was most remarkable in the sample treated within 30 minutes after venipuncture. When the dissociation occurred, no adherent platelet was found on microscopical examinations. Complete blood cell counts and their histogram patterns after dissociation were almost same as those just after venipuncture. The dissociation occurred as soon as the antibiotics were added and remained fairly long time. The dissociation decreased in proportion to the periods of time between venipuncture and addition of antibiotics. The dissociation was caused by many other antibiotics. However, severer damage were found morphologically by adding most of them in both histogram patterns and microscopical examinations than those of aminoglycoside or peptide antibiotics.

Adolescent↗