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Biomedical subjects

H Aoki

Publications and source records attributed to H Aoki.

At least 235 records · Page 13Linked to original sources
PubMed1995

Mutations in the v-mos gene abolish its ability to induce differentiation but not transformation.

The v-mos oncogene product has the ability to induce differentiation in human monocytic leukemia U937 cells, thereby arresting cell proliferation, and also exhibits transforming activity in mouse NIH3T3 cells. Mutation in the v-mos gene consisting of one or two amino acid substitutions in the putative ATP-binding domain impaired its differentiation-inducing activity although mutant proteins showed rather higher levels of autophosphorylation in vitro. Macrophage-specific characteristics such as their morphology, expression of C3b receptor and Fc receptor, and production of interleukin-1 beta and tumor necrosis factor alpha, were equally diminished in cells transfected with mutant mos genes when compared to those with intact v-mos. The ability of the gene to arrest the proliferation of U937 cells was likewise diminished, while the transforming efficiency of the intact and mutant mos genes were essentially the same. These results suggest that the mos product functions differently in cell differentiation and transformation.

3T3 Cells↗
PubMed1994

High-performance liquid chromatographic determination of the new quinolone antibacterial agent DU-6859a in human serum and urine using solid-phase extraction with photolysis-fluorescence detection.

A sensitive and specific HPLC method for the determination of DU-6859a (I), a fluoroquinolone antibacterial agent, in human serum and urine was developed. Compound I and the internal standard extracted from serum and urine by means of a Bond Elut C8 LRC cartridge showed recoveries of 96%. The extracts were chromatographed on a reversed-phase column with photolysis-fluorescence detection. This unique detection method was 42.5 times more sensitive than intrinsic fluorescence detection, the limits of detection being in 3.43 ng/ml for serum and 4.35 ng/ml for urine. In addition, I was stable in serum and urine for at least 1 month at -20 degrees C. The proposed method was sensitive and selective enough to apply to pharmacokinetic studies of I in humans after a single oral dose of 100 mg.

Anti-Infective Agents↗
PubMed1994

Nucleotide sequence of a rice root ferredoxin-NADP+ reductase cDNA and its induction by nitrate.

A ferredoxin-NADP+ reductase (FNR) cDNA was isolated from a lambda gt 11 cDNA library constructed from the roots of nitrate-induced rice (Oryza sativa L. cv. Kinmaze) seedlings. The nucleotide sequence of this clone contains a 1134 nucleotide open reading frame. The N-terminal 62 amino acid stretch was assigned to the transit sequence, followed by 316 residues for the mature protein. The rice root FNR shows only 49% sequence identity to that of the leaf enzyme, but the regions of the binding sites to ferredoxin, NADP-PPi and NADP+ are highly conserved between the two enzymes. The root FNR mRNA was induced transiently by the addition of nitrate, but not by ammonia. The results support the view that the root FNR is involved in the nitrate assimilation in nonchlorophyllous tissues.

Amino Acid Sequence↗
PubMed1994

Prognostic implications of meningiomas in the elderly (over 70 years old) in the era of magnetic resonance imaging.

During the 5 years from 1987 to 1991, 89 elderly patients, aged 70 years and over, were admitted to departments of neurosurgery in Yamaguchi prefecture with meningioma. The clinical features and prognostic implications of meningioma in the elderly were assessed retrospectively. Seventy-eight (88%) of the 89 patients underwent surgery, which was a higher rate than has been previously reported. The length of clinical history was also shorter than in previous studies, and was partly due to the recent introduction of magnetic resonance imaging (MRI). The incidence of poor prognosis (severe disability, vegetative or dead) in the elderly and a younger group aged less than 70 years was 13% and 7%, respectively, but the difference was not statistically significant. In the surgically treated elderly group, age did not influence the patient's outcome. The factors affecting the outcome were pre-operative neurological deficit (p < 0.05), histological malignancy (p < 0.05), and multiple operations (p < 0.05). Twenty-seven of the elderly meningioma patients were in good physical condition with minimal neurological involvement. They underwent total removal of the tumour at the first operation, and the histological diagnosis was benign. Twenty-five of these 27 patients fell into the best outcome category. Therefore, age alone was not a factor preventing proper surgical treatment of meningioma in the elderly.

Aged↗
PubMed1994

Treatment of sepsis by extracorporeal elimination of endotoxin using polymyxin B-immobilized fiber.

Despite the use of potent antibiotics and intensive supportive care, mortality remains high among septic shock patients, especially those with endotoxemia. To remove endotoxin directly from the blood, a material consisting of polymyxin B that is immobilized on fibers (PMX-F) and that can selectively detoxify endotoxin was developed. In a preliminary clinical study, 16 patients with septic multiple organ failure were treated with direct hemoperfusion using a PMX-F column. This therapy significantly decreased the endotoxin level from 76 pg/mL to 21 pg/mL after 2 hours of direct hemoperfusion. The hyperdynamic state of the cardiac index, which is a characteristic of endotoxic shock, returned to normal levels after treatment. In septic shock patients with a systolic pressure of less than 100 mm Hg, the systolic arterial pressure increased significantly from the pretreatment level. The alleviation of fever caused by this therapy continued until the day after treatment. Of the 16 patients who underwent this therapy, 9 were alive 2 weeks after this therapy and 7 patients were discharged from the hospital alive. Hemoperfusion with PMX may be an effective treatment for sepsis and septic shock.

Biocompatible Materials↗
PubMed1994

Intraoral computed radiography using the Fuji computed radiography imaging plate. Correlation between image quality and reading condition.

The quality of images obtained by a new method of intraoral computed radiography using three types of imaging plates and a drum scanner designed exclusively for use with an imaging plate was investigated. The aperture size for reading of radiographic data from the imaging plate and for film recording was 50, 100, or 150 microns 2. The results indicated that high resolution type imaging plate for mammography produced the best image quality. For each imaging plate, it was also found that the image quality improved as the aperture size was decreased. However, the high resolution type IP even at the aperture size of 100 microns 2 showed diagnostic accuracy as high as the image processing of conventional periapical radiographs. This finding suggests that this new imaging system using an imaging plate at the reading and recording aperture size 100 microns 2 has promise for use in intraoral radiography.

Evaluation Studies as Topic↗
PubMed1994

Immunohistochemical localization of growth hormone receptor in cyclic human ovaries.

It has been demonstrated that co-administration of growth hormone (GH) augments ovarian response to human menopausal gonadotrophin, and GH itself increases steroidogenesis in cultured ovarian cells. It is not clear, however, whether the effects of GH on the ovary are direct or not. We performed immunohistochemistry using specific monoclonal antibodies against human GH receptor on 51 specimens of pre-menopausal human ovaries from various phases of the menstrual cycle to detect and localize GH receptors. Immunohistochemical localization of P450 aromatase and 3 beta-hydroxysteroid dehydrogenase was performed using these enzymes as immunohistochemical markers for steroidogenesis in these ovaries. GH receptor immunoreactivity was observed in luteinized granulosa cells in corpora lutea in the luteal phase, which are considered to be active in steroid production. In the follicular phase, GH receptor immunoreactivity was detected in the granulosa layer of only three out of 35 antral follicles. These results demonstrate that immunoreactivity of GH receptor is present in human ovaries, suggesting a direct action of GH on human ovarian functions, especially during luteal phase.

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

pH-sensitive dissociation and association of beta-N-acetylhexosaminidase from boar sperm acrosome.

beta-N-Acetylhexosaminidase (beta-Hex, EC, 3.2.1.52) was released from cauda epididymal boar sperm by treatment with ionophore A23187, indicating that this enzyme is localized in the acrosome. beta-Hex was extracted on a large scale, with 2% acetic acid containing 0.2% Brij 35, from washed ejaculated sperm. By gel filtration chromatography, beta-Hex was separated into a high-molecular-weight fraction (beta-Hex I) and a low-molecular-weight fraction (beta-Hex I). beta-Hex I, which is predominant under acidic conditions (pH 6.5), dissociated into beta-Hex II under alkaline conditions (pH 7.4). beta-Hex II, converted from beta-Hex I, associated again to form beta-Hex I under acidic conditions. By sequential chromatography on ion-exchange, lectin, gel filtration, and ion-exchange HPLC columns, beta-Hex I and II were purified 1200-fold and 4000-fold, respectively, with a combined recovery of 23% as measured with synthetic substrate. An inhibitor of beta-Hex, O-(2-acetamido-2-deoxy-D-glucopyranosylidene) amino N-phenyl-carbamate (PUGNAC), reduced the in vitro fertilization rate in porcine cumulus-enclosed eggs, but barely changed the rate when cumulus-free eggs were used. beta-Hex I was shown to possess cumulus dispersion activity, suggesting that beta-Hex plays a role in the passing by sperm through cumulus cells before they bind to the zona pellucida.

Acetylglucosamine↗