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T Oka

Publications and source records attributed to T Oka.

At least 181 records · Page 10Linked to original sources
PubMed1999

CH5+: the infrared spectrum observed

Protonated methane, CH5+, has unusual vibrational and rotational behavior because its three nonequivalent equilibrium structures have nearly identical energies and its five protons scramble freely. Although many theoretical papers have been published on the quantum mechanics of the system, a better understanding requires spectral data. A complex, high-resolution infrared spectrum of CH5+ corresponding to the C-H stretching band in the 3.4-micrometer region is reported. Although no detailed assignment of the individual lines was made, comparison with other carbocation spectra strongly suggests that the transitions are due to CH5+.

Journal Article↗
PubMed1999

Analysis of the fatty acid components in a perchloric acid-soluble protein.

We had previously found that a perchloric acid-soluble protein (PSP1) occurs in rat liver, and that this novel protein inhibits protein synthesis in a rabbit reticulocyte lysate system (T. Oka, H. Tsuji, C. Noda, K. Sakai, Y.-H. Hong, I. Suzuki, S. Muñoz, Y. Natori, J. Biol. Chem. 270 (1995) 30060-30067). In the present study, we analyzed lipid components bound to PSP1. Native PSP1 was purified from rat liver using Sephadex G-75, DE-52 cellulose and IgGPSP-affinity chromatography, and the lipid components were extracted. The components obtained from the purified PSP1 were shown to be free fatty acids by thin-layer chromatography. By GC-MS, six major fatty acids were identified as 14:0, 16:0, 18:0, 18:1, 18:2 and 20:4. 1 mol of PSP1 contained 1.26 mol of total fatty acid components. The fatty acid-binding assay of PSP1 showed that the Bmax was 1.25 mol fatty acid/mol PSP1 and the Kd value for palmitic acid was 6.03 microM. The concentration of PSP1 mRNA in rat liver increased 2.3-fold by the administration of peroxisome proliferator, bezafibrate. These findings show that PSP1 is a fatty acid-binding protein-like protein, which is involved in the intracellular metabolism of fatty acid and is quite different from the known fatty acid-binding proteins.

Animals↗
PubMed1999

Context-dependent transcriptional cooperation mediated by cardiac transcription factors Csx/Nkx-2.5 and GATA-4.

Although the cardiac homeobox gene Csx/Nkx-2.5 is essential for normal heart development, little is known about its regulatory mechanisms. In a search for the downstream target genes of Csx/Nkx-2. 5, we found that the atrial natriuretic peptide (ANP) gene promoter was strongly transactivated by Csx/Nkx-2.5. Deletion and mutational analyses of the ANP promoter revealed that the Csx/Nkx-2.5-binding element (NKE2) located at -240 was required for high level transactivation by Csx/Nkx-2.5. We also found that Csx/Nkx-2.5 and GATA-4 displayed synergistic transcriptional activation of the ANP promoter, and in contrast to previous reports (Durocher, D., Charron, F., Warren, R., Schwartz, R. J., and Nemer, M. (1997) EMBO J. 16, 5687-5696; Lee, Y., Shioi, T., Kasahara, H., Jobe, S. M., Wiese, R. J., Markham, B., and Izumo, S (1998) Mol. Cell. Biol. 18, 3120-3129), this synergism was dependent on binding of Csx/Nkx-2.5 to NKE2, but not on GATA-4-DNA interactions. Although GATA-4 also potentiated the Csx/Nkx-2.5-induced transactivation of the artificial promoter that contains multimerized Csx/Nkx-2.5-binding sites, Csx/Nkx-2.5 reduced the GATA-4-induced transactivation of the GATA-4-dependent promoters. These findings indicate that the cooperative transcriptional regulation mediated by Csx/Nkx-2.5 and GATA-4 is promoter context-dependent and suggest that the complex cis-trans interactions may fine-tune gene expression in cardiac myocytes.

Animals↗
PubMed1999

Twenty-four-hour preservation in gamma-hydroxybutyrate improves lung function in a canine single-lung allotransplantation.

BACKGROUND: We investigated the effect of gamma-hydroxybutyrate (GHB) when added to the low-potassium University of Wisconsin (LPUW) solution used for the preservation of canine lung for 24 hr. We also examined the effect of pretreatment of donor and recipient dogs with GHB on lung function after transplantation. METHODS: Two groups were investigated. In the LPUW group, donor lungs were flushed with LPUW solution without GHB. In the GHB group, donor and recipient dogs were pretreated with GHB, and donor lungs were flushed with LPUW containing GHB. RESULTS: Posttransplant graft function was best in the GHB group. At 1 hr after reperfusion, PaO2 in the GHB group (475.7+/-96.2 mmHg) was significantly higher than in the LPUW group (188.3+/-102.7 mmHg, P<0.05). Furthermore, the use of GHB resulted in a significant increase in lung compliance (28.3+/-6.5 ml/cm H2O) compared with LPUW group (21.5+/-2.8 ml/cm H2O). CONCLUSIONS: Our results suggest that GHB is potentially useful for functional improvement of hypothermically preserved canine lung allografts after reperfusion.

Adenosine↗
PubMed1999

Prospective Randomized Study of Cyclophosphamide, Epirubicin, and 5-Fluorouracil versus Cyclophosphamide, Adriamycin, and 5-Fluorouracil in Advanced or Recurrent Breast Cancer.

BACKGROUND: Treatment with cyclophosphamide, adriamycin, and 5-fluorouracil (CAF), a widely used, potent regimen is sometimes restricted by the myelotoxicityand myocardiotoxicity of adriamycin (ADR). In a prospective randomized controlled study of patients with advanced or recurrent breast cancer, the efficacy and toxicity of a CEF regimen, in which epirubicin (EPI) was substituted for ADR, was compared with CAF. METHODS: 138 female patients under 75 years of age who had unresectable or recurrent breast cancer during the period from October, 1989 to September, 1991, were randomized to one of two treatment regimens. The first regimen consisted of cyclophosphamide 100 mg p.o. d1-14, adriamycin 30 mg/m(2) i.v. d1, 8 and 5-fluorouracil 500 mg/m(2) i.v. d1, 8 (CAF). In the second regimen, EPI 30 mg/m(2) i.v. d1, 8was substituted for ADR (CEF). Both regimens were delivered q4 weeks. RESULTS: Of 138 patients, 105 (CEF 56, CAF 49) were evaluable for response and survival, and all were evaluable for toxicity (CEF 68, CAF 70). The median course of lots CEF and CAF was 3 cycles. Response rates (complete response plus partial response) with CEF and CAF were 35.7% (20/56) and 36.7% (18/49), respectively. Adverse effects were similar in the two groups, but severe leukopenia (CEF 36.8%, CAF 64.3%) and hepatic toxicity (CEF 1.5%, CAF 12.9%) were encountered more frequently with CAF than with CEF. The duration of 50% survival was 135.9 weeks for CEF and 172.1 weeks for CAF (not significant). CONCLUSION: At an equal dose of EPI and ADR response rates and survival of the CEF group were similar to those of the CAF group, but adverse effects were fewer in the CEF group.

Journal Article↗
PubMed1999

Identification and cloning of rat galectin-2: expression is predominantly in epithelial cells of the stomach.

A complementary DNA clone preferentially expressed in the gastrointestinal tract was obtained from a rat stomach library. The protein coded by the clone had a single carbohydrate recognition domain having conserved motifs for beta-galactoside binding and showed 67% amino acid identity with human galectin-2. The recombinant protein synthesized in Escherichia coli could bind to an asialofetuin column and was eluted with beta-galactopyranoside. From these observations, we named the protein rat galectin-2 coded by the cDNA. The rat galectin-2 was predominantly expressed in the epithelial cells of stomach. Thus this protein may form a mucin layer cross-linking with the beta-galactoside moiety of glycoproteins.

Amino Acid Sequence↗
PubMed1999

The effect of tissue factor pathway inhibitor on hepatic ischemic reperfusion injury of the rat.

BACKGROUND: Tissue factor (TF) is an initiation factor for blood coagulation, and its expression is induced on macrophages and endothelial cells during the inflammatory or immune responses. In a previous study, we reported the significance of TF expression in hepatic ischemic reperfusion injury using a rat model. Recently, tissue factor pathway inhibitor (TFPI) has been discovered, and the effect of TFPI has been assessed in vivo. In this study, therefore, we studied the effect of TFPI on hepatic ischemic reperfusion injury of the rat. METHODS: After laparotomy of Lewis rats, the branches of the hepatic artery and portal vein leading to the median, left, and caudate lobes of the liver were clamped. The liver was reperfused after 120 or 180 min of ischemia. Simultaneously, recombinant human TFPI (4 mg/kg) was injected via a superiomesenteric vein. Rats were sacrificed at 5, 12, and 24 hr after reperfusion, and liver tissues were harvested. TF expression was studied by immunohistochemical staining with the monoclonal antibody (HTF-K108). RESULTS: Survival rates over a 5-day period were examined after the ischemic time of 120 and 180 min. Seven of 10 rats in the 120-min ischemia group (n=10), and only 1 (10%) rat of 10 in the 180-min ischemia group (n=10) survived. However, by the treatment with TFPI, all of the rats in the 120-min ischemia group (n=10), and six rats in the 180-min ischemia group (n=10) survived (P<0.05). The serum concentrations of alanine aminotransferase (ALT) and thrombin-antithrombin complex (TAT) before ischemia were 30.0+/-2.3 IU/L and 4.7+/-1.4 ng/ml, respectively (n=5). These levels showed a peak at 3-5 hr after reperfusion (ALT: 13909+/-1900 IU/L, TAT: 30.4+/-7.0 ng/ml) (P<0.01). However, both peak levels were decreased by the treatment with TFPI (ALT: 6017+/-1290 IU/L, TAT: 5.4+/-2.1 ng/ml) (P<0.01). Although TF was strongly stained on endothelial cells and Kupffer cells accumulating to the site of the necrosis in the control group, the area of the necrosis and the grade of TF staining were significantly reduced in the TFPI-treated group. CONCLUSIONS: These results indicated that TFPI strongly inhibited the injury of the ischemic reperfusion, and confirmed that TF played a pivotal role in the development of ischemic reperfusion injury.

Animals↗
PubMed1999

Pharmacokinetics of cisplatin in analbuminemic rats.

The effect of protein binding on the pharmacokinetics of cisplatin (cis-diamminedichloroplatinum (II); CDDP) has been studied in analbuminemic rats, which genetically lack albumins, in comparison with normal rats. CDDP was reported to highly bind to serum components, and the major binder was thought to be an albumin. However, there were no significant differences in the serum disappearance profiles of platinum after intravenous (iv) bolus injection of CDDP to analbuminemic rats as compared with normal rats. The total body clearance, Cl(tot), of platinum in normal rats was 48.7+/-22.0 mL h(-1) (5 mg kg(-1)), 55.9+/-4.04 mL h(-1) (10 mg kg(-1)) and 49.0+/-3.57 mL h(-1) (20 mg kg(-1)), whereas Cl(tot) in analbuminemic rats was 52.0+/-8.48 mL h(-1) (5 mg kg(-1)), 62.9+/-10. 8 mL h(-1) (10 mg kg(-1)) and 62.8+/-6.81 mL h(-1) (20 mg kg(-1)). The serum blood urea nitrogen (BUN) and creatinine levels at 6 h after iv injection were higher in both groups of rats who received CDDP than those of pre-dose level. However, there were no significant differences in the renal function tests between analbuminemic rats and normal rats. The binding of CDDP to the serum samples obtained from analbuminemic rats and normal rats was measured by a centrifuging filtration method. The binding percentages were 68.0+/-5.9% (2.0 microg mL(-1)), 56.8+/-4.1% (5.0 microg mL(-1)) and 64.6+/-4.4% (10.0 microg mL(-1)) in analbuminemic rats and 52.9+/-3.5% (2.0 microg mL(-1)), 52.2+/-3.4% (5.0 microg mL(-1)), 56.9+/-1.9% (10.0 microg mL(-1)) in normal rats. Higher binding percentages were obtained in analbuminemic rats than in normal rats. In vitro binding studies under the two incubation conditions (5 min and 2 h) showed that the binding percentages of CDDP to serum proteins were 59.2+/-3.2% (5 min) and 72.3+/-6.5% (2 h) for albumin, 42.3+/-1.9% (5 min) and 39.5+/-2.5% (2 h) for alpha(1)-acid glycoprotein (AAG) and 51.7+/-5.3% (5 min) and 49. 2+/-1.9% (2 h) for gamma-globulin. From these studies, it was elucidated that albumin is not the major ligand in the rat serum and that other proteins also have important roles in the pharmacokinetics of CDDP.

Animals↗
PubMed1999

Infrared Spectroscopy of H3O+: The nu1 Fundamental Band.

The infrared spectrum of H3O+ in positive column discharges of H2/O2 gas mixtures has been studied by a difference frequency laser spectrometer. The nu1 fundamental band of H3O+ was identified in the region of the strong. Molecular constants were obtained by the least-squares fitting of the observed frequencies, and band origins of the and subbands were determined to be 3389.656(2) and 3491.170(2) cm-1, respectively. During this study, assignment of the nu3 fundamental band was extended to higher J, K transitions, which do not fit to the calculated pattern well, but have definitely been assigned by using the ground state combination differences and relative intensities. Vibration-rotation interactions between the nu1 and nu3 states have been considered, which explained some large discrepancies between observed and calculated frequencies and led to the identification of forbidden transitions. Energy differences in the ground state between the DeltaK = 3 rotational levels were obtained from the combination differences of the forbidden and allowed transitions, which led to an accurate determination of C and DK. Equilibrium structure of H3O+ has been derived to be re = 0.974(1) Å and alphae = 113.6(1) degrees. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Pulmonary blastoma: report of a case.

We herein describe a 27-year-old male presenting with a pulmonary blastoma. The patient was admitted to our hospital with the chief complaints of fever and left back pain. Chest roentgenograms showed a tumor measuring 10 cm in diameter in a lower lobe of the left lung. Computed tomography and magnetic resonance imaging revealed a well demarcated and heterogeneously enhanced tumor. Although a histological diagnosis could not be obtained by a transbronchial biopsy, image analyses led us to suspect it to be malignant. The patient underwent a left lower lobectomy with lymph node dissection. A histopathological examination revealed the tumor to be a biphasic type of pulmonary blastoma. Because of the rapid progress of the tumor and the difficulty in making a preoperative diagnosis in such cases, an immediate surgical resection is therefore recommended in cases with even the slightest suspicion of malignancy.

Adult↗
PubMed1999

Surgical treatment for a supra sinotubular junctional saccular aneurysm associated with aortic regurgitation.

We reported a patient with a saccular ascending aortic aneurysm located just above the non-coronary sinotubular junction. The aneurysm produced severe aortic regurgitation and two episodes of cardiac tamponade. By intraoperative inspection, the border between the aneurysmal wall and non-dilated portion of the normal aortic wall was distinct, and the aortic valve leaflets and aortic annulus appeared normal. Aortic valve dysfunction appeared to be caused by dilation of the noncoronary sinotubular junction and mild distortion of the noncoronary sinus because of the aneurysmal formation. We performed patch closure of the aneurysmal ostium and repaired the dilated noncoronary sinotubular junction. Postoperative echocardiography and aortography demonstrated a good coaptation of the aortic valve leaflets with trivial aortic regurgitation. Although a rupture site, dissection or carcinomatous pericarditis which is attributable to the two episodes of cardiac tamponade could not be found, pathologic examination of the aneurysm wall revealed intramural blood leakage between the mucoid degenerated media and notably thickened adventitia. In addition, there was thinning and interruption of the elastic fibers of the media. These findings are consistent with a leaking aneurysm which cause the slow development of cardiac tamponade.

Aortic Aneurysm↗
PubMed1999

Extended resection for lung cancer invading mediastinal organs.

We analyzed 49 patients with non-small-cell lung cancer invading mediastinal organs such as the left atrium (15), superior vena cava (13), trachea (11), aorta (5), thoracic vertebral body (4) and esophagus (1). Lung resection included lobectomy (37), pneumonectomy (8) and limited resection (4). Twenty-seven patients underwent carina- or bronchoplasty. Complete resection was possible in 35 patients. Operative mortality was 12% and overall 5-year survival was 13%. Median survival time was 519 days. Factors significantly affecting survival were the completeness of resection, node status, and histological type. Five-year survival was 18% with complete resection and 0% with incomplete resection (p < 0.0001). Five-year survival for patients with squamous cell carcinoma was 36% and for those with other types of lung cancer, 0% (p < 0.02). Five-year survival for patients classified pathologically as N0 or N1 was 36% and, for those classified as N2 or N3, 0% (p < 0.05). We concluded that aggressive resection for lung cancer invading the mediastinal organs involves a high mortality rate, making selectivity important. Patients undergoing complete resection, classified as N0 or N1, and having squamouse cell carcinoma may benefit most from surgery.

Adult↗
PubMed1999

Production of functional rat liver PSP protein in Escherichia coli.

An efficient Escherichia coli expression system for the production of a perchloric acid-soluble protein (PSP) has been constructed. Complementary DNA encoding PSP was inserted into an inducible bacterial expression vector pGEX-4T-1. After the plasmid introduced into E. coli was expressed by isopropyl 1-thio-beta-D-galaetopyranoside (IPTG), the recombinant product was purified by glutathione-Sepharose 4B affinity chromatography. The purified product showed the expected NH2-terminal sequence, but the translation inhibitory activity of this product was 10 times lower compared with that of authentic PSP isolated from rat liver.

Animals↗
PubMed1999

A pair of invertedly repeated genes in Chlamydomonas reinhardtii encodes a zygote-specific protein whose expression is UV-sensitive.

Uniparental inheritance of the chloroplast genome has been observed in a wide variety of green plants. In Chlamydomonas this phenomenon, which can be selectively inhibited by UV irradiation of mt(+) gametes, has been shown cytologically to be due to the preferential degradation of mt(-)-derived chloroplast nucleoids in young zygotes. The zygote-specific pair of zys1 genes, zys1A and zys1B, is expressed earliest among five genes isolated from a "10-min" zygote library. We report here that the ZYS1 protein, which is encoded by the invertedly duplicated zys1 gene, accumulates in zygotes and is localized in nuclei. In addition, when mt(+) gametes (but not mt(-) gametes) are UV-irradiated before mating, only very limited accumulation of ZYS1 protein can be detected in the resulting zygotes.

Algal Proteins↗
PubMed1999

Transthoracoscopic needle biopsy for indeterminate lung nodules.

BACKGROUND: The usefulness of transthoracoscopic needle biopsy for preoperatively indeterminate intrapulmonary nodules was evaluated. METHODS: Thoracoscopy was performed on 38 patients with pulmonary solitary nodules suspected to be primary lung carcinomas. When the nodule was localized by simple observation or tactile sensor, a biopsy specimen of the tumor was obtained by a biopsy needle introduced through a trocar. RESULTS: The nodules were 7 to 55 mm in diameter. All were located in the peripheral region of the lung. Biopsy specimens were obtained even from 17 nodules with no associated pleural changes. By cytology, all the malignant tumors were precisely diagnosed, 29 as primary lung cancers and 3 as metastatic lung neoplasms. Five of the remaining six benign nodules were not precisely diagnosed. However, they were cytologically classified as class I. CONCLUSIONS: Transthoracoscopic needle biopsy is feasible for diagnosing small intrapulmonary nodules, particularly those of malignant neoplasms. As compared with thoracoscopic excisional biopsy, transthoracoscopic needle biopsy saves time and may reduce the possibility of tumor dissemination during the procedure.

Adult↗
PubMed1999

Thymic cystectomy through subxyphoid by video-assisted thoracic surgery.

In this paper we present a new technique for thymic cystectomy by video-assisted thoracic surgery. The thoracoscope was inserted using a Vein Harvest (Ethicon Endo-Surgery Co, Ltd, Cincinnati, OH) through a 5-cm subxyphoid incision. A Harmonic Scalpel (Ethicon Endo-Surgery) and Cherry Dissector (Ethicon Endo-Surgery) were used for dissection. The thymic cyst was successfully removed through the incision without thoracotomy. The advantage of this technique is that it is less invasive than video-assisted thoracic surgery through the thorax, removing the need for a thoracotomy.

Aged↗