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Biomedical subjects

T Okabe

Publications and source records attributed to T Okabe.

At least 181 records · Page 10Linked to original sources
PubMed1995

Premature termination mutation (772Glu-->stop) in the hormone-binding domain of the androgen receptor in a patient with the receptor-negative form of complete androgen insensitivity syndrome.

We have characterized the androgen receptor in a Japanese infant with complete androgen insensitivity syndrome (or androgen resistance), and have investigated the molecular basis. Androgen binding was undetectable in cultured genital skin fibroblasts from this patient by whole-cell androgen receptor binding assay. Sequence analysis of the entire coding region of the androgen receptor gene from this patient revealed a single nucleotide substitution (G-->T) at nucleotide position 2676 in exon E (or 5), resulting in conversion of glutamine codon (GAG) to amber stop codon (TAG) at amino acid position 772 within the hormone-binding domain of the androgen receptor. This premature termination mutation (or nonsense mutation), introducing a truncated androgen receptor that lacks most of its androgen binding capacity, is though to cause the receptor-negative form of complete androgen insensitivity syndrome in this patient.

Base Sequence↗
PubMed1995

Purification and characterization of angiotensin II degradation factor from porcine endothelial cells.

We investigated the degradation of angiotensin II by vascular endothelial cells and smooth muscle cells in vitro. When angiotensin II was incubated with confluent culture of endothelial cells or with serum free conditioned medium of the endothelial cells, angiotensin II was destroyed rapidly. When angiotensin II was incubated with cultured vascular smooth muscle cells or their serum free conditioned medium, degradation was not observed. To identify the angiotensin II degradation factor (ADF), we have purified ADF from the conditioned medium of endothelial cells, by column chromatographies, i.e., hydroxyapatite, ion exchange and gel filtration chromatography. The partially purified ADF had apparent molecular masses of 154 kDa on gel filtration chromatography. Its pH optimum was about 7.0. ADF was inhibited by p-chloromercuribenzoic acid, iodoacetamide and high concentration of EDTA, but not by diisopropyl fluorophosphate, bestatin, amastatin or pepstatin A. Of the synthetic substrates examined, ADF degrades human angiotensin II, [Val5]-angiotensin II and [Asn1, Val5]-angiotensin II. It did not degrade angiotensin I.

Ammonium Sulfate↗
PubMed1995

[A case of bilateral infection-induced urolithiasis in a bed-ridden elderly female].

A 79-year-old bedridden female in whom bilateral small renal calculi were pointed nine months previously, presented with a high fever and non-specific abdominal symptoms. A diagnosis of bilateral renal and ureteral stones causing hydronephroureters with severe infection was made. She was referred to the urology department and treated with extracorporeal shock wave lithotripsy (ESWL). Persistent urinary tract infection caused by urease-producing bacteria, often seen in the bedridden elderly contributes to form infection-induced renal calculi. Such calculi are sometimes found in bilateral kidneys, can grow rapidly, and can often form with few, if any, symptoms. ESWL has been established as noninvasive treatment of choice for the great majority of upper urinary tract stones. All types of stones, including renal staghorn calculi, can be treated by ESWL with endourological support. Recurrence of stones after treatment is expected in approximately 40% of cases. In order to prevent recurrence, the stone should be removed totally and the patients must be observed carefully to keep the urinary tract totally free of infection.

Aged↗
PubMed1995

[Squamous cell carcinoma of the lung with high CT number, but without calcification].

Squamous cell carcinoma of the lung was diagnosed in a 64-year-old man. Chest roentgenographic and tomographic examinations did not show areas of high-density in the tumor, but chest CT scan showed diffuse, scattered, high-density nodules in the tumor. Histologic examination did not show calcification, and calcium staining (Kossa method) was negative. Examination of the thin-slice CT, the soft X-ray film, and the resected slice of the lung indicated that the high-density nodules seen in the tumor on the chest CT scan corresponded to markedly fibrotic lesions with severe anthracosis. This case shows that high-density areas on a CT scan may reflect non-calcified lesions.

Calcinosis↗
PubMed1995

Effect of glass ionomer manipulation on early fluoride release.

PURPOSE: To determine the amount of fluoride released from several glass ionomer products [Fuji Cap II, Fuji Ionomer Type II, Ketac-Silver, Chelon-Silver, and Miracle Mix (hand-mixed and encapsulated)], and to compare them between triturated (5, 10, 15 seconds) encapsulated and hand-mixed glass ionomers. MATERIALS AND METHODS: The amount of fluoride released at 1, 2, 3, 7, 14, 21 and 28 days after the start of immersion in deionized-distilled water at 37 degrees C was determined with a fluoride ion selective electrode. Rates of fluoride release and cumulative amounts of fluoride release were calculated. RESULTS: Each glass ionomer released the greatest amount of fluoride during the first 24-hour period. Although there was some variation between products, generally the hand-mixed specimens released significantly (P < 0.05) less fluoride than those prepared by mechanical trituration (10 and 15 seconds). The cumulative amounts of fluoride released from the mechanically triturated glass ionomers were significantly (P < 0.05) greater than the amounts released from the hand-mixed glass ionomers. No significant differences in the cumulative amounts of fluoride released from triturated materials were found among the different trituration times.

Analysis of Variance↗
PubMed1995

[A case of metamorphopsia caused by a very localized spotty infarct].

A 51-year-old woman complained that her right side of the face looked blurring and the right margin of all the objects in her visual field looked blurred. Neurological examination on admission showed no abnormalities including higher cortical function and visual fields except the metamorphopsia. In this case, a very localized spotty infarct caused no neurological symptoms other than the metamorphopsia. CT scan and MRI revealed a spotty lesion of infarct between retrosplenium and cingulate gyrus on the left side. This can be a breakthrough case to locate the exact anatomic pathology that causes metamorphopsia.

Cerebral Infarction↗
PubMed1995

Molecular cloning of an Actinobacillus pleuropneumoniae outer membrane lipoprotein (OmlA) from serotype 5a.

The gene encoding an outer membrane lipoprotein (OmIA) was cloned from Actinobacillus pleuropneumoniae strain NG-8 (serotype 5a). The deduced amino acid sequence of OmIA from strain NG-8 showed 61% identity to the OmIA from serotype 1 strain, which confers protective immunity to pigs. Southern blot analysis showed the presence of a sequence highly homologous to the omIA gene of strain NG-8 in strains of serotype 5a, 5b and 10. A specific serum against OmIA of NG-8 also detected a homologous protein in the strains of these serotypes. These data shows the presence of antigenic variability among A. pleuropneumoniae OmIA proteins.

Actinobacillus Infections↗
PubMed1995

Shorter interval between cycles of cyclophosphamide, doxorubicin, cisplatin using recombinant human granulocyte colony-stimulating factor for urothelial cancer--phase I/II study.

BACKGROUND: Despite improvement in the response rate and protraction of the progression-free period of urothelial cancer produced by chemotherapy, severe bone marrow suppression often results in delays in the initiation of treatment cycles and/or decreases in drug dosages. Reduction of leukopenia during chemotherapy has been demonstrated by the combined administration of granulocyte colony-stimulating factor (G-CSF) in various malignancies. METHODS: A phase I/II study was conducted to assess whether the interval between cycles of CISCA (cyclophosphamide, doxorubicin, cisplatin) chemotherapy could be shortened under support of recombinant human granulocyte colony-stimulating factor (rhG-CSF) for urothelial cancer. Three or more patients with transitional cell carcinoma of the urinary tract were allocated to each of four different treatment intervals (step 1: 28 days, step 2: 21 days, step 3: 17 days, and step 4: 14 days) by reducing the interval in a step-wise manner. Two mg/kg/day of a rhG-CSF, lenograstim, was injected subcutaneously on days 3 to 16 (until day 14 for the 14-day interval group). RESULTS: Sixteen patients were enrolled, four patients were treated with the step 1 protocol, five with step 2, four with step 3, and three with step 4. Leukopenia/neutropenia was the most severe toxic reaction, but none of the patients at any step manifested neutropenia of WHO grade 4 for more than four days. There were no significant differences in the hematological and nonhematological toxicities among the 4 steps. Seven of eight patients with measurable diseases were treated with CISCA on shortened schedules (steps 2-4), and one complete remission (CR) and four partial responses (PR) were demonstrated. CONCLUSIONS: CISCA chemotherapy supported by rhG-CSF was safely shortened to a 14-day interval in the pilot study. The potential role of rhG-CSF in shortening the interval of CISCA, as well as the benefit of the intensified schedule, remains to be clarified.

Adolescent↗
PubMed1994

Tetanus toxin and Clostridium perfringens enterotoxin as tools for the study of exocytosis.

The role of calmodulin in exocytotic secretion was studied using digitonin-permeabilized bovine adrenal chromaffin cells to examine the effect of calmodulin directly introduced into the cells and using tetanus toxin as a specific inhibitor of exocytotic secretion. Addition of calmodulin to the permeabilized cells increased Ca(2+)-dependent norepinephrine release in a dose-dependent manner. The enhancement of release by calmodulin was specific to calmodulin: bovine serum albumin, actin, and caldesmon had no such effect. Enhancement of release by calmodulin occurred at Ca2+ concentrations of more than 10(-6) M and increased with an increase of Mg2+ concentration. The release of norepinephrine enhanced by calmodulin was inhibited by tetanus toxin. These results indicate directly that calmodulin plays an important role in exocytotic secretion from chromaffin cells. Exocytosis is known to occur by fusion of plasma membrane with limiting membranes of secretory vesicles following an increase in intracellular Ca2+. We used the enterotoxin of Clostridium perfringens type A as a specific tool to modify plasma membrane permeability to induce calcium influx. Multigranular exocytosis was recognized electron-microscopically in addition to the single-granular exocytosis in rat anterior pituitary cells and pancreatic acinar cells treated with the enterotoxin in the presence of extracellular Ca2+. The treatment with the enterotoxin did not induce any drastic change in the fine membrane structures of both types of cells. The enterotoxin-treated anterior pituitary cells and pancreatic acinar cells should provide a useful system for studying the molecular mechanism of fusion of membranes in exocytosis.

Adrenal Medulla↗
PubMed1994

Purification and characterization of a cell growth factor from a human leukemia cell line: immunological identity with ferritin.

We have succeeded in long-term cultivation of a human erythroleukemia cell line, K-562-T1 (T. Okabe, M. Fujisawa, and F. Takaku, Proc. Natl. Acad. Sci. USA, 81: 453-455, 1984). The cells grown in a protein-free chemically defined medium have been shown to produce cell growth factors (A. Mihara et al., In Vitro Cell. Dev. Biol., 23: 317-322, 1987). In this study, we have purified a cell growth factor from the conditioned medium that stimulates the proliferation of human leukemia cells, HL-60. In the purified factor, two major protein bands of 24 kDa and 22 kDa were identified on a sodium dodecyl sulfate-polyacrylamide gel. The 22 kDa protein was stained with a monoclonal antibody to the light chain of ferritin. The growth-promoting activity of the purified factor was coprecipitated with a monoclonal antibody to the light chain or heavy chain of human ferritin. These results suggest that K-562-T1 cells produce a cell growth factor that is related to ferritin.

Culture Media, Conditioned↗
PubMed1994

Purification of a cell growth factor from a human lung cancer cell line: its relationship with ferritin.

We have purified a cell growth factor from a human lung cancer cell line, T3M-30, which was established in a protein-free chemically defined medium. The factor, designated carcinoma-derived growth factor (CD-GF), stimulated proliferation of a variety of cells, including human leukemia cells, HL-60, and melanoma cells, SK-28. Half-maximum stimulation by the purified CD-GF was achieved at a concentration of 40 ng/ml. In the purified CD-GF, two major protein bands of 24 kDa and 22 kDa were identified on a SDS polyacrylamide gel. The partial amino acid sequences of the 24 kDa protein were determined from two peptide fragments obtained by V8 protease treatment. The partial sequences were identical to those of heavy chain of human ferritin. The activity of the purified CD-GF was coprecipitated completely with a monoclonal antibody to heavy chain of ferritin. Ferritin has been considered to inhibit cell growth. However, human heart ferritin was capable of stimulating the growth of HL-60 cells. These results suggest that CD-GF is related to ferritin and ferritin is a growth factor of HL-60 leukemia cells.

Amino Acid Sequence↗
PubMed1994

Quick-freeze, deep-etch visualization of exocytosis in anterior pituitary secretory cells: localization and possible roles of actin and annexin II.

The exocytotic process in the anterior pituitary secretory cells was studied using quick-freeze deep-etch electron microscopy, fluorescein-isothiocyanate-phalloidin staining, heavy meromyosin decoration, and immuno-electron microscopy. The subcortical actin filaments are distributed unevenly in the peripheral cytoplasm. Few secretory granules are seen beneath the plasma membrane in the region where the peripheral cytoplasm is occupied by numerous subcortical actin filaments. On the contrary, in the region free of the subcortical actin filaments, many secretory granules lie in contact with the plasma membrane. Thus, the subcortical actin filaments may control the approach of the secretory granules to the plasma membrane in these cells. The granule and plasma membranes that lie in close proximity are linked by intervening strands. Unfused portions of both membranes remain linked by these strands during membrane fusion and opening. These strands may be involved in membrane contact, fusion and opening during exocytosis. Annexin II (calpactin I) has been demonstrated immunocytochemically to be localized at the contact sites between the granule and plasma membranes, and is therefore a possible component of the intervening strands. Membrane fusion starts within focal regions of both membranes less than 50 nm in diameter. The plasma membrane shows inward depressions toward the underlying granules immediately before fusion. The disappearance of intramembranous particles from the exocytotic site of the membrane has not been observed.

Actins↗
PubMed1994

Correlation of cytotoxicity with element release from mercury- and gallium-based dental alloys in vitro.

OBJECTIVES: An in vitro screening test was used to compare the cytotoxicity and elemental release from mercury- and gallium-based dental restorative materials. METHODS: The test employed three sequential extractions of the samples into cell-culture medium which were then used to evaluate the cytotoxicity of the samples and the release of elements from the samples. Cytotoxicity was measured by placing the extract in contact with Balb/c mouse fibroblasts for 24 h and measuring the succinic dehydrogenase activity of the cells. The release of elements was measured by means of atomic absorption spectrophotometry. RESULTS: Samples of Tytin (Kerr) showed no cytotoxicity compared to Teflon controls. Dispersalloy (Johnson and Johnson) was severely cytotoxic initially when Zn release was greatest, but was less toxic between 48 and 72 h as Zn release decreased. Gallium Alloy GF (Tokuriki Honten) was moderately cytotoxic after 8 h, and increased in cytotoxicity thereafter, which correlated with a substantial and persistent release of Ga from this material. SIGNIFICANCE: The results of the current study concurred with in vivo assessments of these materials, and the use of sequential extractions was useful in determining trends in the cytotoxicity and elemental release from these materials.

3T3 Cells↗
PubMed1994

Hospital-wide PACS with a digital image intensifier TV system.

Tokyo Hitachi Hospital, Hitachi Ltd., has used a hospital-wide PACS for over 1 year. The system runs a 100 Mb/s optical fiber network over the whole hospital including wards and outpatient clinic rooms, with 11 image workstations. The network links digital imaging modalities such as X-CT, MRI, computed radiography (CR) and digital radiography (DR) with a 2048 x 2048 (2k x 2k) matrix image intensifier television (I.I.-TV) system. These modalities generate about 200 images/day. The system has managed over 300,000 images of about 8000 patients so far. Although being still under improvement, the system has really been used for routine work. The hospital-wide PACS of a small hospital has been proved to be very useful for both image diagnosis and image management.

Computer Terminals↗
PubMed1994

BE-23372M, a novel and specific inhibitor for epidermal growth factor receptor kinase.

The fungal metabolite BE-23372M is a structurally novel protein kinase inhibitor. Its IC50 for epidermal growth factor (EGF) receptor kinase was 0.03 microM. IC50 values of BE-23372M for other protein tyrosine kinases, erbB-2, p43v-abl, insulin receptor kinase, and p60c-src were 0.42, 1.0, 3.3, and 4.5 microM, respectively, and the IC50 for protein kinase C, a serine/threonine kinase, was 4.1 microM. Cdc2 kinase, casein kinases I and II and cAMP-dependent protein kinase were not inhibited by 20 microM BE-23372M. A kinetic study showed that BE-23372M was competitive with respect to the substrate peptide and to ATP. Autophosphorylation of solubilized EGF receptor kinase was clearly inhibited by 0.1 microM BE-23372M. Autophosphorylation of EGF receptor in A431 cells was also inhibited. These results show that BE-23372M is a potent and specific EGF receptor kinase inhibitor. It should be a valuable tool for EGF receptor kinase research.

Amino Acid Sequence↗
PubMed1994

Reduced mercury vapor release from dental amalgams prepared with binary Hg-in liquid alloys.

For the past ten years, the amounts of mercury vapor released from dental amalgams and the possibility of side-effects caused by these amounts have been discussed. Although no adverse health effects have been substantiated from these minute amounts, besides rare cases of allergies, this release should be reduced. The aim of this study was to reduce the mercury evaporation from a high-copper amalgam during setting by triturating the alloy powder with binary Hg-In liquid alloys having various indium concentrations set at 0, 5, 10, 20, 30, 40, and 50 wt%. Specimens (n = 4) were made for each amalgam according to ANSI/ADA Specification #1 and placed into a measuring chamber kept at 36.5 +/- 0.5 degrees C, through which a continuous air flow of 0.75 L/min was pumped. The total mercury release was measured during the setting period, according to the method described by Ferracane et al. (1992). Four additional specimens were prepared from a modified 14% Indisperse amalgam powder for the purpose of comparison. The results showed that the release of mercury vapor decreased with increasing indium concentrations, and that the amalgams made with the Hg-In liquid alloy with 10% In or more released significantly less mercury than the modified 14% Indisperse. The method of mixing indium in mercury prior to trituration appeared to be another effective method for reducing mercury evaporation during setting. The reduced mercury release may be explained by a reduction of mercury concentration in the structure, a reduction of vapor pressure for the mercury in the matrix phases, or more efficient formation of a surface oxide layer.

Dental Amalgam↗
PubMed1994

Digestion of endothelin-1 on cultured vascular smooth muscle cells.

The degradation of 125I-endothelin-1 (125I-ET-1) was examined on cultured porcine aortic endothelial cell (EC) and rat vascular smooth muscle cell (SMC) by HPLC analysis. The degradation of ET-1 was observed on SMC and was slightly observed on EC. Membrane fractions of SMC had a strong potency for the degradation of ET-1 and retained activity even in plasma. This activity was inhibited with some of the noble inhibitors which were known as enkephalinase inhibitors. These results suggest that endothelin degradation enzyme on SMC is related to enkephalinase and that this enzyme plays a significant role in the degradation of ET-1 in vivo.

Animals↗