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Biomedical subjects

T Okano

Publications and source records attributed to T Okano.

At least 217 records · Page 12Linked to original sources
PubMed1996

In vitro metabolism of the vitamin D analog, 22-oxacalcitriol, using cultured osteosarcoma, hepatoma, and keratinocyte cell lines.

Using four cultured cell models representing liver, keratinocyte, and osteoblast, we have demonstrated that the vitamin D analog, 22-oxacalcitriol is degraded into a variety of hydroxylated and side chain truncated metabolites. Four of these metabolic products have been rigorously identified by high pressure liquid chromatography, diode array spectrophotometry, and gas chromatography-mass spectrometry analysis as 24-hydroxylated and 26-hydroxylated derivatives as well as the cleaved molecules, hexanor-1alpha,20-dihydroxyvitamin D3 and hexanor-20-oxo-1alpha-hydroxyvitamin D3. Comparison with chemically synthesized standards has revealed the stereochemistry of the biological products. Although differences exist in the amounts of products formed with the different cell types, it is apparent that 22-oxacalcitriol is subject to metabolism by both vitamin D-inducible and noninducible enzymes. Time course studies suggest that the truncated 20-alcohol is derived from a side chain hydroxylated molecule via a hemiacetal intermediate and the 20-oxo derivative is likely formed from the 20-alcohol. Biological activity measurements of the metabolites identified in our studies are consistent with the view that these are catabolites and that the biological activity of 22-oxacalcitriol is due to the parent compound. These results are also consistent with recent findings of others that the biliary excretory form of 22-oxacalcitriol is a glucuronide ester of the truncated 20-alcohol.

Animals↗
PubMed1996

Induction of apoptosis in murine clonal osteoblasts expressed by human T-cell leukemia virus type I tax by NF-kappa B and TNF-alpha.

We investigated the effects of various cytokines in the presence of human T-cell leukemia virus type I (HTLV-I) tax protein in murine clonal osteoblasts, MC3T3-E1 cells. Skeletal remodeling by osteoclasts and osteoblasts is coordinated by cytokines, which are activated by HTLV-I tax protein via nuclear factor-kappa B (NF-kappa B). MC3T3-E1 cells were cocultured with an irradiated HTLV-I-producing lymphocyte cell line, MT-2. After coculture, the tumor necrosis factor-alpha (TNF-alpha) level in the medium was markedly elevated during the 7 days of culture, and MC3T3-E1 cells underwent apoptotic cell death. Marked apoptosis was also observed in MC3T3-E1 cells treated with MT-2 culture medium and in HTLV-I tax-expressing MC3T3-E1 clones, which both expressed high levels of TNF-alpha. This apoptosis was prevented by treatment with neutralizing anti-TNF-alpha antibody (alpha TNF). HTLV-I tax protein and TNF-alpha induced activation of NF-kappa B in apoptotic MC3T3-E1 cells. Decreased NF-kappa B activation was observed in HTLV-I tax-expressing MC3T3-E1 cells treated with alpha TNF. Our results suggest that HTLV-I tax activated NF-kappa B and subsequently TNF-alpha, leading to apoptosis of osteoblasts.

Animals↗
PubMed1996

Preparation and characterization of the micelle-forming polymeric drug indomethacin-incorporated poly(ethylene oxide)-poly(beta-benzyl L-aspartate) block copolymer micelles.

To estimate the feasibility of novel containers for drugs, poly(ethylene oxide)-poly(beta-benzyl L-aspartate) (PEO-PBLA) micelles were prepared by dialysis against water using different solvents. The solvent selected is very important because it drastically affects the stability of polymeric micelles. The critical micelle concentration (cmc) of the prepared micelles in distilled water was determined by a fluorescence probe technique using pyrene. Indomethacin (IMC) as a model drug was incorporated into the micelles by dialysis and an oil/water emulsion method. Characteristics of PEO-PBLA micelles without and with the physically trapped IMC in the inner core of the micelles (IMC/PEO-PBLA) were studied by dynamic light scattering and gel permeation chromatography/HPLC as well as an in vitro release test of IMC from the micelles. For the PEO-PBLA block copolymers, N,N-dimethylacetamide (DMAc) was found to be the best of the solvents tested to form stable polymeric micelles with a narrow size distribution and avoid its aggregation, and the cmc of PEO-PBLA micelles thus prepared was determined to be ca. 18 mg/L in water. The diameters of PEO-PBLA micelles and IMC/PEO-PBLA micelles in number averaged scale were observed to be ca. 19 and 25-29 nm, respectively. The release study of IMC from IMC/PEO-PBLA micelles in various buffer solutions at the pH range from 1.2 to 7.4 at 37 degrees C revealed that the release rate of IMC from the micelles was increased by increasing the pH of the medium and indicated that the release rate of IMC from the micelles are controlled by the partition coefficient of IMC based on the pH of the medium and interaction between IMC and the hydrophobic portion of the micelles.

Chemistry, Pharmaceutical↗
PubMed1996

A case of renal cell carcinoma associated with synchronous contralateral renal pelvic cancer and bladder tumor.

We report a case of renal cell carcinoma associated with synchronous contralateral renal pelvic cancer and bladder tumor. The patient underwent total nephroureterectomy for the left renal pelvic cancer with transurethral resection of the bladder tumor. After 2 courses of combination chemotherapy, we performed surgical enucleation of the right renal cell carcinoma. Although transurethral resection of the recurrent bladder tumors was undergone 17 months after the last operation, the patient retains normal renal function.

Carcinoma, Renal Cell↗
PubMed1996

Cytoplasmic calcium levels and membrane fluidity of platelets in contact with polyether-polyamide multiblock-copolymer surfaces.

Cytoplasmic calcium levels and the membrane fluidity of rabbit platelets stored in mini blood bags of crystalline-amorphous microstructured polymers (polyether-polyamide multiblock-copolymers) were studied. Fluorescent dye (Fura 2 or 1,6-diphenyl-1,3,5-hexatriene)-loaded platelet suspensions were stored at 37 degrees C for 1 h in the blood bags, and metabolic changes in the platelets during storage were evaluated by the fluorescent spectroscopic technique. The surfaces of poly(vinyl chloride) and polyolefin elastomers, which are used for commercially available blood bags, enhanced the progress of platelet metabolism; i.e., there was a dramatic decrease in membrane fluidity and an increase in [Ca2+]i. Furthermore, the decrease in membrane fluidity was observed prior to the increase in [Ca2+]i. These results suggest that the decrease in membrane fluidity of platelets in contact with polymer surfaces can be the dominant stage in the activation of these platelets. In contrast, the surfaces of polyether-polyamide multiblock-copolymers exhibited few changes in either membrane fluidity or [Ca2+]i levels. These results suggest that the platelets in contact with the crystalline-amorphous microstructured copolymer surfaces can be inert and inactivated in terms of the prevention of a decrease in membrane fluidity.

Animals↗
PubMed1996

Amine effect on phenylboronic acid complex with glucose under physiological pH in aqueous solution.

A new "intelligent' polymer system was developed utilizing the binding and exchange of phenylboronic acid (PBA) with polyols and/or glucose. In this improved system, an amine component was incorporated into the polymer chain along with PBA, to enhance binding between PBA and glucose under physiological conditions. The PBA-based polymer was formed by free-radical copolymerization of 3-methacrylamidophenylboronic acid (MAPB) with comonomers, N,N-dimethylaminopropylacrylamide (DMAPAA) and acrylamide (AAm) in the presence of N,N'-methylenebis(acrylamide) (Bis-AAm) as a cross-linker. The proportion of the amount of PBA groups complexed with glucose vs total amount of PBA groups was determined by the batch method. Compared to PBA copolymers synthesized without amine component, the proportion increased as a function of the amine content as well as the pH of the buffer. These results confirm that the interaction of neighboring amines (unprotonated) to PBA strengthens the binding with glucose, especially at pH 7.4 and above. This new PBA-amine copolymer is promising as a material useful for polyol separation, protection of polyols, and possibly, as an insulin delivery device.

Acrylamide↗
PubMed1996

Synthetic studies of vitamin D analogs. XXII. Synthesis and antiproliferation activity of putative metabolites of 1 alpha, 25-dihydroxy-22-oxavitamin D3.

As putative metabolites of 1 alpha,25-dihydroxy-22-oxavitamin D3 (OCT), 24-hydroxylated OCT in 24(R) and 24(S) forms, 24-ketoOCT, 26-hydroxylated OCT in 25(S) and 25(R) forms, pentanorOCT and pentanor-ketoOCT were synthesized from the steroidal 20(S)-alcohol. Their antiproliferation activities towards human promyelocytic leukemia cells (HL-60 cells) are also reported. Oxidized derivatives at the C-24 position, 24-ketoOCT, 24(R)-hydroxylated OCT and 24(S)-hydroxylated OCT, showed activities comparable to or slightly weaker than that of OCT, while 26-hydroxylated OCT was less active than OCT. Truncated OCT, pentanor OCT and pentanor-ketoOCT, were inactive at 10(-7)-10(-10) M.

Animals↗
PubMed1996

[Prognostic factors in patients with non-metastatic renal cell carcinoma].

BACKGROUND: The objective of this study is to evaluate prognostic factors of non-metastatic renal cell carcinoma using univariate and multivariate statistical methods. METHODS: 390 patients who were performed radical surgery in our hospital between 1960 and 1994 were entered to this study. Kaplan-Meier method with log-rank test and Cox's proportional hazard model were used for statistical analysis. RESULTS: Chief complaints, tumor localization on kidney, tumor size, fever, hemoglobin, C-reactive protein, erythrocyte sedimentation rate, immunosuppressive acidic protein, operative method, blood loss, histologic grade, cell type, pT, pN and pV revealed to have prognostic statistical significance in the univariate analysis. Whereas, sex, age, blood type, hypertension, affected side and preoperative embolization did not. In the multivariate analysis of the preoperatively evaluable factors, CRP, tumor size and tumor localization proved to be significant prognostic predictors in this order. When the pathological factors were included to the multivariate analysis, pV, historogic grade and pN revealed to be significant prognostic predictors in this order. CONCLUSION: These results suggest that pathological factors were significant prognostic predictors for non-metastatic renal cell carcinoma.

Carcinoma, Renal Cell↗
PubMed1996

[Effects of essential trace elements on bone turnover--in relation to the osteoporosis].

Trace Elements are essential for normal growth and development of skeletons in humans and animals. Although they are minor building components in teeth and bone, they play important functional roles in bone metabolism and bone turnover. Fluoride accumulates in new bone formation sites and results in a net gain in bone mass. Aluminum induces impairment of bone formation by the inhibition of osteoblastic function. Magnesium enhances bone turnover by through the stimulation of osteoclastic function. Zinc regulates secretion of calcitonin from thyroid grand and influences on bone turnover. Gallium suppresses bone turnover in humoral hypercalcemia of malignancy in a similar mechanism as aluminum and cadmium. Copper induces low bone turnover by both suppressions of osteoblastic and osteoclastic functions. Iodine as the hormonal forms of thyroxine and triiodothyronine enhances bone turnover. Among the trace elements in bone and hair, significant differences were found in the contents of zinc, copper and manganese between normal subjects and osteoporotic patients. However, exact involvements of the trace elements in osteoporosis have not yet been clarified.

Animals↗
PubMed1996

[A case report of pulmonary blastoma--well differentiated fetal adenocarcinoma].

We report a pulmonary blastoma lacking sarcomatous features in 33-year-old woman. Abnormal shadow was detected in the right upper field in a routine chest X-ray film. The preoperative imaging films showed a 4 x 4 cm, well-circumscribed solid tumor in S3 of the right lung. The preoperative clinical diagnosis of primary lung cancer was considered. The operative findings showed that an elastic hard tumor, 5 cm in diameter, was localized in S3 of the right lung and partially contacted the middle lobe. Right upper and middle lobe resection was performed with lymph node dissection. The postoperative diagnosis was pulmonary blastoma, well differentiated fetal lung (= WDFA). It is considered that the degree of the malignancy of WDFA is lower and the prognosis of WDFA is better than conventional pulmonary blastoma (= biphasic blastoma). There are not available treatments except for surgical resection. It is suggested that it necessary to collect as many cases as possible, to make definite classifications and to examine the clinical course and prognosis of pulmonary blastoma.

Adenocarcinoma↗
PubMed1996

[Bilateral renal cell carcinoma with extension into the vena cava associated with von Hippel-Lindau disease: a case report and review of the literature].

We report a case of bilateral renal cell carcinoma with extension into the inferior vena cava associated with von Hippel-Lindau (VHL) disease. A 52-year-old woman was referred to our hospital for further examination of bilateral renal masses which were found on abdominal ultrasound examination. The diagnosis was confirmed with renal angiography, abdominal computed tomography (CT), abdominal magnetic resonance-CT (MRI), cavography and head MRI. Right adjunctive nephrectomy and removal of the tumor thrombus were performed. She has been treated with interferon-alpha after the operation. The analysis of her DNA by using single strand conformational polymorphism revealed a VHL gene abnormality.

Carcinoma, Renal Cell↗
PubMed1996

[Squamous cell carcinoma of ureter in a patient with functional solitary kidney treated by partial ureterectomy: a case report].

We report a case of squamous cell carcinoma of ureter. A 60-year-old female was referred to our hospital for the right hydronephrosis and the left atrophic kidney. She had been suffering from severe renal dysfunction and had hemodialysis a month earlier. Retrograde and antegrade right pyelography revealed complete obstruction of the right lower ureter about 2 cm in length. Transcutaneous retrograde left pyelography revealed vesicoureteral junction stenosis. After improvement of the renal function by transcutaneous right nephrostomy, the patient underwent right partial ureterectomy. Pathological examination revealed squamous cell carcinoma, grade 2, pT3 in the right ureter. Neither local recurrence nor distant metastasis has occurred for 19 months and the patient retains moderate renal function. We reviewed sixty-four cases of ureteral squamous cell carcinoma in the Japanese literature and discussed the renal parenchymal sparing surgery for the disease.

Carcinoma, Squamous Cell↗
PubMed1995

Primary structure of a gamma subunit of G protein, gamma 12, and its phosphorylation by protein kinase C.

We have determined the primary structure of a novel gamma subunit (gamma 12, previously designated gamma S1) of G protein purified from bovine spleen. The mature gamma 12 protein composed of 68 amino acids had acetylated serine at the N terminus and geranylgeranylated/carboxylmethylated cysteine at the C terminus. This was consistent with the C-terminal prenylation signal in the amino acid sequence, which was predicted from gamma 12 cDNA isolated from a bovine spleen cDNA library. Western blots with the specific antibody against gamma 12 showed that gamma 12 is present in all tissues examined. Among various gamma subunits (gamma 1, gamma 2, gamma 3, gamma 7, and gamma 12), gamma 12 has a unique property to be phosphorylated by protein kinase C. The phosphorylated amino acid residue was Ser1 (or Ser2). The phosphorylated beta gamma 12 associated with Go alpha more tightly than the unphosphorylated form. Exposure of Swiss 3T3 and aortic smooth muscle cells to phorbol 12-myristate 13-acetate and NaF induced phosphorylation of gamma 12. Stimulation of aortic smooth muscle cells with natural vasoactive agents such as angiotensin II and vasopressin also induced phosphorylation of gamma 12. The extent of phosphorylation of beta gamma 12 in vitro was suppressed by a complex formation with Go alpha, which was relieved by the addition of guanosine 5'-O-(3-thiotriphosphate) or aluminum fluoride. These results strongly suggest that gamma 12 is phosphorylated by protein kinase C during activation of receptor(s) and G protein(s) in living cells.

Amino Acid Sequence↗
PubMed1995

Purification and low temperature spectroscopy of gecko visual pigments green and blue.

We purified two kinds of visual pigments, gecko green and gecko blue, from retinas of Tokay geckos (Gekko gekko) by two steps of column chromatography, and investigated their photobleaching processes by means of low temperature spectroscopy. Absorption maxima of gecko green and blue solubilized in a mixture of 3-[(3-cholamidopropyl)dimethylammonio]-1- propanesulfonate (CHAPS) and phosphatidylcholine were 522 and 465 nm, respectively, which are close to those observed in the photoreceptor cells. Low temperature spectroscopy identified six intermediates in the photobleaching process of gecko green; batho (lambda max = 569 nm), BL (lambda max = 519 nm), lumi (507 nm), meta I (approximately 486 nm), meta II (approximately 384 nm), and meta III intermediates (approximately 500 nm). In contrast to the high similarity in amino acid sequence between gecko green and iodopsin [Kojima, D., et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 6841-6845], the batho-green did not revert thermally to original gecko green but converts to the next intermediate. The photobleaching process of gecko blue was investigated by low temperature spectroscopy, and three intermediates, meta I (lambda max = approximately 470 nm), meta II (lambda max = approximately 370 nm) and meta III (lambda max = approximately 475 nm), were identified. A comparative study on the thermal behavior of meta intermediates revealed that the thermal stability of meta II intermediate of both of the gecko visual pigments is lower than that of metarhodopsin II. The result supports the idea that both the gecko visual pigments are cone-type ones.

Animals↗
PubMed1995

Thrombin receptor-mediated synovial proliferation in patients with rheumatoid arthritis.

Synovial cell proliferation is one of the pathological bases of rheumatoid arthritis (RA). Several cytokines including IL-1 and IL-6 and growth factors have been shown to be involved in the synovial cell proliferation in RA. Thrombin is a multifunctional protease and acts as a mitogen for several cell types through its specific receptor. To assess whether thrombin is involved in overproliferation of rheumatoid synovial cells, we measured the concentration of thrombin-anti-thrombin III (ATIII) complex (TAT) in synovial fluid obtained from patients with RA or osteoarthritis (OA). We also examined the effect of thrombin or thrombin receptor agonist peptide (TRAP) on cell growth of synovial cell clones (SCCs) established from an RA patient. The concentrations of TAT in the synovial fluid from patients with RA were significantly higher than in those with OA. Moreover, both thrombin and TRAP enhanced proliferation of synovial cells in vitro. We also characterized the expression of thrombin receptor mRNA by reverse transcription-PCR. The expression of mRNA for thrombin receptor was up-regulated by thrombin or TRAP stimulation. Thrombin receptor antigen was also detected on both SCCs and synovial tissue from RA patients by immunostaining using a monoclonal antibody against thrombin receptor. These findings indicate that thrombin may act as a mitogen for synovial cells through thrombin receptor and may play some role in synovial overproliferation and remodeling in RA.

Adult↗
PubMed1995

Mechanism of cell detachment from temperature-modulated, hydrophilic-hydrophobic polymer surfaces.

Poly(N-isopropylacrylamide) (PIPAAm), exhibiting a lower critical solution temperature (LCST) at 25 degrees C in physiological phosphate buffered saline solution (pH 7.4) and at 32 degrees C in pure water, was grafted onto the surfaces of commercial polystyrene cell culture dishes. This PIPAAm-grafted surface exhibited hydrophobic surface properties at temperatures over the LCST and hydrophilic surface properties below the LCST. Endothelial cells and hepatocytes attached and proliferated on PIPAAm-grafted surfaces at 37 degrees C, above the LCST. The cultured cells were readily detached from these surfaces by lowering the incubation temperature without the usual damage associated with trypsinization. In this case, the optimum temperature for cell detachment was 10 degrees C for hepatocytes and 20 degrees C for endothelial cells. Cell detachment was partially inhibited by sodium azide treatment, suggesting that cell metabolism directly affects cell detachment. Morphological changes of the adherent cells during cell detachment experiments indicated further involvement of active cellular metabolic processes. Cells detached from hydrophobic-hydrophilic PIPAAm surfaces not only via reduced cell-surface interactions caused by the spontaneous hydration of grafted PIPAAm chains, but also by active cell morphological changes which were a function of cell metabolism.

Acrylic Resins↗
PubMed1995

Temperature-modulated platelet and lymphocyte interactions with poly(N-isopropylacrylamide)-grafted surfaces.

Temperature-responsive semitelechelic poly(N-isopropylacrylamide) (PIPAAm) bearing a carboxyl end group has been chemically immobilized on aminated polystyrene particle surfaces via condensation reaction. PIPAAm-grafted particles were uniformly suspended in aqueous media at lower temperatures. With increasing temperature, PIPAAm-grafted particles aggregated and precipitated. Such reversible changes in particle colloidal behaviour was correlated to temperature-modulated hydrophilic/hydrophobic changes of particle surfaces modified by PIPAAm hydration/dehydration with temperature changes. Interactions between platelets and PIPAAm-grafted surfaces were studied by monitoring cytoplasmic free Ca2+ concentration ([Ca2+]i) changes in platelets using intracellularly-trapped Ca2+ indicator dye, Fura 2, at various temperatures. Although changes in [Ca2+]i in platelets in contact with PIPAAm-grafted particles were not observed below the critical temperature of PIPAAm, significant changes in [Ca2+]i in platelets were induced by contact with particles above this critical temperature. Furthermore, temperature-modulated cell adsorption/desorption control by PIPAAm-grafted particles was investigated using a particle aggregation assay in the presence of lymphocytes. Below the critical temperature of PIPAAm, mixed suspensions were completely homogeneous due to minimal interaction between lymphocytes and hydrated particles. In contrast, aggregated precipitates were observed by increasing the suspension temperature above the critical temperature of PIPAAm resulting from strong hydrophobic interactions between particles with lymphocytes. These precipitates are reversibly resuspended in cold buffer. The feasibility of cell activation/inactivation or cell attachment/detachment control by temperature-modulated surface changes is attractive for suspension cell culture and drug delivery at targeted sites in vivo.

Acrylic Resins↗