Biomedical subjects

T Okabe

Publications and source records attributed to T Okabe.

At least 19 recordsLinked to original sources

PubMed2000

Substance P induces tumor necrosis factor-alpha release from human skin via mitogen-activated protein kinase.

Substance P plays an important role in neurogenic inflammation with granulocyte infiltration. To investigate cytokines involved in the substance P-induced inflammation and the mechanism of cell activation, we studied the release of TNF (tumor necrosis factor)-alpha and histamine from human skin slices in response to substance P and antigen. Substance P induced the release of histamine and TNF-alpha in a dose-dependent manner at concentrations from 0.8 to 100 microM. PD 098059 (2'-amino-3'-methoxyflavone) selectively inhibited the release of TNF-alpha, but not the release of histamine induced by either substance P or antigen. SB 203580 ([4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-++ +imida zole]) slightly inhibited TNF-alpha release induced by antigen, but not that induced by substance P, and slightly enhanced histamine release induced by either stimulation. The release of TNF-alpha in response to either stimulation was inhibited by 1 nM-1 microM dexamethasone, but histamine release was not affected. These results suggest that substance P, in addition to antigen, induced TNF-alpha release from human skin by a mitogen-activated protein (MAP) kinase, predominantly extracellular signaling-regulated protein kinase (ERK)-dependent, and dexamethasone-sensitive pathway, which is separate from that for histamine release from mast cells.

Adult↗

PubMed2000

A focused compound library of novel N-(7-indolyl)benzenesulfonamides for the discovery of potent cell cycle inhibitors.

A series of compounds containing an N-(7-indolyl)benzenesulfonamide pharmacophore was synthesized and evaluated as a potential antitumor agent. Cell cycle analysis with P388 murine leukemia cells revealed that there were two different classes of potent cell cycle inhibitors; one disrupted mitosis and the other caused G1 accumulation. Herein described is the SAR summary of the substituent patterns on this pharmacophore template.

Cell Cycle↗

PubMed2000

L-152,804: orally active and selective neuropeptide Y Y5 receptor antagonist.

Neuropeptide Y (NPY) elicits food intake through the action of hypothalamic G-protein-coupled receptors. Previous publications indicate that the Y5 receptor may represent one of these postulated hypothalamic "feeding" receptors. Using a potent and orally available Y5 antagonist L-152,804, we evaluated the involvement of the Y5 receptor in feeding regulation. L-152,804 displaced [125I]peptide YY (PYY) binding to human and rat Y5 receptors with Ki values of 26 and 31 nM, respectively, and inhibited NPY (100 nM)-induced increase in intracellular calcium levels via human Y5 receptors (IC50 = 210 nM). L-152,804 did not show significant affinity for human Y1, Y2, and Y4 receptors at a dose of 10 microM. Intracerebroventricular (i.c.v.) (30 microg) or oral (10 mg/kg) administration of L-152,804 significantly inhibited food intake evoked by i.c.v.-injected bovine pancreatic peptide (bPP, 5 microg; a moderately selective Y4, Y5 agonist) in satiated SD rats. However L-152,804 did not significantly inhibit i.c.v. NPY (5 microg; a Y1, Y2, Y5 agonist)-induced food intake. These findings suggest that L-152,804 is a selective and potent non-peptide Y5 antagonist with oral bioavailability and brain penetrability. In addition, the anorexigenic effects of L-152,804 on bPP-induced feeding revealed participation of the Y5 receptor in feeding regulation, while i.c.v. administration of NPY does not appear to significantly contribute to Y5 stimulated food intake. We conclude that the potent and orally active Y5 antagonist, L-152,804, represents a useful tool to address the physiological role of the Y5 receptor.

Administration, Oral↗

PubMed2000

Shear bond strengths of polymethyl methacrylate to cast titanium and cobalt-chromium frameworks using five metal primers.

STATEMENT OF PROBLEM: Poor chemical bonding of a denture base resin to cast titanium frameworks often introduces adhesive failure and increases microleakage. PURPOSE: This study examined the shear bond strengths of a denture base resin to cast pure titanium, Ti-6Al-4V, and a cobalt-chromium alloy using various adhesive primers. MATERIAL AND METHODS: Disks (6.0 mm diameter, 2.5 mm thick) were cast of the 3 alloys. The disk surfaces were grit-blasted with 50 microm alumina and treated with 5 different metal primers (Metal Primer II ¿MP]; Cesead Opaque primer ¿OP]; Meta Base ¿MB]; experimental primer ¿EP]; Siloc bonding system ¿SI]). A denture base resin (Palapress Vario) was then applied on the disks with hole-punched sticky tape (bonding area of 5.0 mm) and a Teflon (PTFE, New Age Industries Inc, Willow Grove, Pa.) ring (6.0 mm diameter x 2.0 mm thick). Specimens without primer were also prepared as controls. All specimens were immersed in 37 degrees C water and thermocycled up to 2,000 cycles. Shear bond strength values were determined at a crosshead speed of 0.5 mm/min. Data were statistically analyzed using 3-way ANOVA, followed by 1-way ANOVA and the Scheffé multiple range test. RESULTS: Primers significantly (P <.05) improved shear bond strengths of denture base resin to all metals, among which no significant differences were found. Specimens primed with OP, MP, and EP showed higher bond strengths than did those primed with MB. After thermocycling, the bond strengths of MB and SI decreased substantially; MB showed the least durability (22.8% to 35.5% decrease) among the primers. CONCLUSION: The application of 5 primers significantly improved the shear bond strengths of a denture base resin to cast CP titanium, Ti-6Al-4V, and Co-Cr alloy. OP and MP primers exhibited greater bond strength and durability than did MB and SI.

Analysis of Variance↗

PubMed2000

Cutting efficiency of air-turbine burs on cast titanium and dental casting alloys.

OBJECTIVE: The purpose of this study was to investigate the cutting efficiency of air-turbine burs on cast free-machining titanium alloy (DT2F) and to compare the results with those for cast commercially pure (CP) Ti, Ti-6Al-4V alloy, and dental casting alloys. METHODS: The cast metal (DT2F, CP Ti, Ti-6Al-4V, Type IV gold alloy and Co-Cr alloy) specimens were cut with air-turbine burs (carbide burs and diamond points) at air pressures of 138 or 207 kPa and a cutting force of 0.784 N. The cutting efficiency of each bur was evaluated as volume loss calculated from the weight loss cut for 5 s and the density of each metal. The bulk microhardness was measured to correlate the machinability and the hardness of each metal. RESULTS: The amounts of DT2F cut with the carbide burs were significantly (p < 0.05) greater than for the other titanium specimens at either 138 or 207 kPa. The diamond points exhibited similar machining efficiency among all metals except for Type IV gold alloy. The increase in the volume loss of Co-Cr alloy (Vitallium) cut with the diamond points showed a negative value (-29%) with an increase in air pressure from 138 to 207 kPa. There was a negative correlation between the amounts of metal removed (volume loss) and the hardness (r2 = 0.689) when the carbide burs were used. SIGNIFICANCE: The results of this study indicated that a free-machining titanium alloy (DT2F) exhibited better machinability compared to CP Ti and Ti-6Al-4V alloy when using carbide fissure burs. When machining cast CP Ti and its alloys, carbide fissure burs possessed a greater machining efficiency than the diamond points and are recommended for titanium dental prostheses.

Alloys↗

PubMed2000

The machinability of cast titanium and Ti-6Al-4V.

This study investigated the machinability (ease of metal removal) of commercially pure (CP) titanium and Ti-6Al-4V alloy. Both CP Ti and Ti-6Al-4V were cast into magnesia molds. Two types of specimens (with alpha-case and without alpha-case) were made for CP Ti and Ti-6Al-4V. Machinability (n = 5) was evaluated as volume loss (mm3) by cutting/grinding the 3.0 mm surface using fissure burs and silicon carbide (SiC) under two machining conditions: (1) two machining forces (100 or 300 gf) at two rotational speeds (15000 or 30000 rpm) for 1 min, and (2) constant machining force of 100 gf and rotational speed of 15000 rpm for 1, 2, 5, 10, and 30 min. As controls, conventionally cast Co-Cr and Type IV gold alloys were evaluated in the same manner as the titanium. When fissure burs were used, there was a significant difference in the machinability between CP titanium with alpha-case and without alpha-case. On the other hand, there was no appreciable difference in the amount of metal removed for each tested metal when using the SiC points.

Alloys↗

PubMed2000

Altered in vitro apoptosis of cultured mast cells prepared from an inbred strain of mice, NC/Kuj.

BACKGROUND: An inbred strain of mice, NC, develops dermatitis associated with highly elevated serum IgE and dermal mast cell hyperplasia. OBJECTIVES AND METHODS: To clarify the mechanisms for the dermal mast cell hyperplasia in NC, we prepared bone marrow-derived mast cells (BMMCs) from three strains of mice, NC/Kuj, C57BL/6 and BALB/c, and compare histamine contents, histamine release abilities, adhesive properties and apoptosis of the BMMCs. RESULTS: Compared with BMMCs obtained from C57BL/6 and BALB/c, NC/Kuj BMMC possessed higher histamine content and higher adhesive ability to plastic plates, although histamine release from BMMCs was found to be similar in the three strains. The most intriguing finding is the lack of apoptosis in the BMMCs from NC/Kuj upon growth factor deprivation as determined by DNA ladder formation and loss of membrane phospholipid asymmetry. CONCLUSION: The altered in vitro properties of mast cells in NC/Kuj partially account for an increase of dermal mast cells, which might be involved in the development of skin lesions in NC.

Animals↗

PubMed2000

Repeat intervention for in-stent restenosis: re-expansion of the initial stent is a predictor of recurrence of restenosis.

BACKGROUND: In-stent restenosis has become a significant clinical problem as use of stents has increased. The optimal strategy for dealing with in-stent restenosis needs to be evaluated. OBJECTIVE: To compare the acute and late results of interventions for in-stent restenosis according to the device used, and to analyze the clinical and procedural variables of the lesions treated and identify the determinants of recurrence of restenosis and target lesion revascularization (TLR). METHODS: Procedural and late outcomes for 58 lesions in 50 patients who underwent repeat intervention for in-stent restenosis were analyzed. The results of interventions according to the device employed were compared. The predictors of recurrence of restenosis and TLR within 6 months were analyzed. The ratio of balloon diameter in repeat intervention to minimal lumen diameter after initial stenting (MLD0) was used as an index of re-expansion of stents. Serial intravascular ultrasound imaging was performed before and after repeat intervention for 33 lesions, and re-expansion of the initial stent was evaluated. RESULTS: Repeat intervention was successful in treating all lesions. Angiographic follow-up was possible for 49 lesions (84%). The overall incidences of recurrence of restenosis and TLR were 40.1 and 27.6%, respectively. Despite the immediate results having been good, the late results of stenting for in-stent restenosis were not favorable. Diffuse-type in-stent restenosis, early in-stent restenosis, and balloon diameter:MLD0 ratio > 1.25 are independent predictors of poor late results. Intravascular ultrasound findings have shown that expansion of the initial stent leads to recurrence of restenosis and TLR. CONCLUSIONS: Re-expansion of the initial stent can cause further vascular injury and there is a risk of recurrence of restenosis. Alternative therapeutic strategies that work without dilating the initial stent may be necessary for treating lesions with high risk of recurrence of restenosis.

Aged↗

PubMed2000

In vitro activities of rabeprazole, a novel proton pump inhibitor, and its thioether derivative alone and in combination with other antimicrobials against recent clinical isolates of Helicobacter pylori.

The MICs of rabeprazole sodium (RPZ), a newly developed benzimidazole proton pump inhibitor (PPI), against 133 clinical Helicobacter pylori strains revealed a higher degree of activity than the another two PPIs, lansoprazole and omeprazole. Time-kill curve assays of RPZ, when combined with amoxicillin, clarithromycin, or metronidazole, disclosed that synergistic effects were demonstrated in combination with each antibiotic examined. Moreover, no apparent antagonistic effect appeared among all of the strains tested.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2000

Limitations of vitek GPS-418 cards in exact detection of vancomycin-resistant enterococci with the vanB genotype.

The susceptibilities of 20 strains of vancomycin-resistant enterococci (VRE) with the vanB genotype obtained by using Vitek GPS-418 cards were compared with those obtained by the broth dilution method of the National Committee for Clinical Laboratory Standards (NCCLS) (approved standard M7-A4) and with those obtained by the agar screen method using bile esculin azide agar containing 6 microgram of vancomycin per ml. Although both the broth dilution and agar screen methods disclosed no discordance, Vitek GPS-418 cards yielded a very major error compared with the results obtained by the reference broth dilution method of the NCCLS. Vitek GPS-418 cards were therefore found to have considerable room for improvement for the accurate detection of vanB VRE strains.

Bacterial Proteins↗

PubMed2000

Differentiation of necrotic cell death with or without lysosomal activation: application of acute liver injury models induced by carbon tetrachloride (CCL4) and dimethylnitrosamine (DMN).

We investigated the relationship between DNA degradation and lysosome activity (loss of lysosomal integrity) in necrotic cell death induced by carbon tetrachloride (CCl4) and dimethylnitrosamine (DMN): coagulation necrosis and hemorrhagic necrosis, respectively. TdT-mediated dUTP-biotin nick end-labeling (TUNEL) and enzyme histochemistry for acid phosphatase were performed in both models and results were analyzed by light microscopy, electron microscopy, and confocal laser scanning microscopy (CLSM). In the CCl(4)-injected liver, TUNEL staining was closely associated with release of lysosomal enzymes into the cytoplasm, and intranuclear deposition of lysosomal enzymes took place at an early stage of subcellular damage. In the DMN-injected liver, TUNEL-positive nuclei tended to have well-preserved lysosomes and centrally localized TUNEL signals. It was assumed that acute hepatocellular damage in the CCl4-injected liver would be characterized by necrotic cell death with lysosome activation and that damage in the DMN-injected liver would be necrotic cell death without lysosome activation. In the DMN-injected liver, DNA degradation may be selectively induced in the nuclear center, in which heterochromatin (including inactive chromatin) is believed to be a target. We concluded that necrotic cell death, i.e., DNA degradation, would be at least divided into two types, with/without association with lysosome activation, represented by necrotic cell death in the CCl4-injected liver and that in the DMN-injected liver.

Acid Phosphatase↗

PubMed2000

Phytogrowth-Inhibitory activities of beta-dolabrin and gamma-thujaplicin, hinokitiol-related compounds and constituents of Thujopsis dolabrata Sieb. et Zucc. var hondai Makino.

Beta-dolabrin and gamma-thujaplicin isolated from Thujopsis dolabrata Sieb. et Zucc. var hondai Makino, like hinokitiol, showed strong phytogrowth-inhibitory activities, and their growth-inhibitory activities were as high as that of sodium 2,4-dichlorophenoxyacetate used as a positive control. In particular, the phytogrowth-inhibitory activity of gamma-thujaplicin was strong and it completely inhibited the germination of this seed of Brassica campestris L. subsp. rapa Hook f. et Anders at the concentration of 30 ppm. Both compounds exhibited inhibitory activities on B. campestris L. subsp. rapa Hook f. et Anders and Sesamum indicum Linne, even at the low concentration of 10 ppm. At 7 d after treatment with beta-dolabrin and gamma-thujaplicin, the amount of chlorophyll in the cotyledons of B. campestris L. subsp. rapa Hook f. et Anders treated with both compounds was greatly decreased as compared with the control. The findings indicate that the phytogrowth-inhibitory action might be a common biological activity of hinokitiol-related compounds, suggesting that at least a part of their phytogrowth-inhibitory actions seems to be related to a decrease in chlorophyll content.

Brassica↗

PubMed2000

Antifungal activity of Hinokitiol-related compounds on wood-rotting fungi and their insecticidal activities.

Hinokitiol (beta-thujaplicin), beta-dolabrin and gamma-thujaplicin isolated from Thujopsis dolabrata SIEB. et ZUCC var hondai MAKINO showed antifungal activities against all of the wood-rotting fungi examined. The antifungal activity of three compounds on Daedalea dickinsii IFO-4979 was especially strong, their minimum inhibitory concentration (MIC) values being 0.2 microg/ml. Their antifungal activities on D. dickinsii IFO-4979 were as high as that of amphotericin B used as a positive control. Three compounds had strong insecticidal activities on Tyrophagus putrescentiae [50%-lethal concentration (LC50 : g/m2) 0.25 in hinokitiol, 0.02 in beta-dolabrin and gamma-thujaplicin. Their insecticidal activities were higher than that of N,N-diethyl-m-toluamide (DEET, LC50 : 1.46 g/m2) used as a positive control. Three compounds also showed strong insecticidal activity on Coptotermes formosanus [LC50 (g/m2) 0.07 in hinokitiol, 0.05 in beta-dolabrin and gamma-thujaplicin], although their insecticidal activities were much lower than that of commercial chloropyrifos (LC50 : 0.00016 g/m2).

Antifungal Agents↗

PubMed2000

[The effect of combination chemotherapy to adapted to chronotherapy with 5-fluorouracil, leucovorin, mitomycin C and cisplatin in patients with gastric or colorectal cancer].

We performed combination chemotherapy adapted to chronotherapy with 5-fluorouracil, leucovorin, mitomycin C and cisplatin in 11 patients with gastric cancer and 7 with colorectal cancer. Treatment consisted of a 5-day course of continuous arterial or intravenous infusion of 5-FU (500 mg/body/day), arterial or intravenous infusion of leucovorin (20 mg/body/day) at 6:00 p.m. on days 1-5, arterial or intravenous infusion of mitomycin C (2 mg/body) at 9:00 a. m. on day 5, and arterial or intravenous infusion of cisplatin (20-80 mg/body) at 6:00 p.m. on day 5. The effective rate against gastric cancer was 73%; however, the effective rate against colorectal cancer was 29%. During and after this therapy, there was only a little appetite loss, nausea and stomatitis.

Aged↗

PubMed2000

[Evaluation of "Helicobacter-Selective-Medium (Nissui Seiyaku)" for rapid detection of Helicobacter pylori].

We evaluated Helicobacter Selective Agar (HSA) medium (Nissui Pharmaceuticals Co., Ltd., Tokyo, Japan), which has been newly developed and has been commercially available since June in 1998. HSA medium strongly inhibited the growth of possible contaminants from gastric biopsy-specimens, such as alpha-streptococci, Neisseria species, Enterococcus gallinarum, Pseudomonas aeruginosa, Corynebacterium species, Capnocytophaga species, and Candida albicans. Cultures run in parallel with Helicobacter Pylori Agar (HPA) medium (Eiken Chemical Co., Ltd., Tokyo, Japan) disclosed no discordance in the detective rates of H. pylori strains between the media examined. Inaddition, the numbers of the colonies and the colony-sizes grown on the plates were also in good agreement with each other. However, it would be strikingly favorable that the appearing colonies on the HSA medium turned purple. This coloration enabled us to detect the emergence of the colonies much earlier and easier when compared with the conventional other media including HPA medium (Eiken). These findings led us to conclude that HSA medium (Nissui) was superior to HPA medium (Eiken) in the prompt detection and the rapid identification of H. pylori in routine clinical microbiology.

Agar↗

PubMed1999

Evaluation of scaffolding effects of five different types of stents by intravascular ultrasound analysis.

The acute elastic recoil of 5 types of stents immediately after deployment by intravascular ultrasound and quantitative coronary angiography measurements was analyzed. Successfully implanted stents were: Palmaz-Schatz in 104 lesions, Gianturco-Roubin in 65, Wiktor in 45, gfx in 22, and Multi-Link stents in 22. Before and after stenting, the cross section of the smallest luminal area and vessel area was measured with intravascular ultrasound. The postdilatation balloon area was calculated by quantitative coronary angiography. Percent recoil was calculated as: [1-(preluminal area)/balloon area)] x 100. The ratio of balloon area-to-vessel area was also compared. Although preluminal areas in Gianturco-Roubin and Palmaz-Schatz stents were similar (2.4 +/- 0.1 vs 2.5 +/- 0.1 mm2, p = NS), postluminal area in the Gianturco-Roubin was significantly smaller than the area in the Palmaz-Schatz (6.3 +/- 0.2 vs 8.3 +/- 0.3 mm2, p <0.05). Although both the balloon area/vessel area (0.68 +/- 0.05, 0.80 +/- 0.08 vs 0.83 +/- 0.02, p <0.05) and the preluminal area (2.1 +/- 0.4, 1.6 +/- 0.2 vs 2.5 +/- 0.1 mm2, p <0.05) were smaller in gfx and Multi-Link than in the Palmaz-Schatz, postluminal area was comparable to the area in the Palmaz-Schatz (7.8 +/- 0.4, 7.4 +/- 0.4 vs 8.3 +/- 0.3 mm2, p = NS). Percent recoil in the Gianturco-Roubin was poorest among these 5 groups. More favorable initial gain can be obtained with Palmaz-Schatz, Wiktor, gfx, and Multi-Link stents than with the Gianturco-Roubin stent.

Aged↗

PubMed1999

Automatic border detection identifies subclinical anthracycline cardiotoxicity in children with malignancy.

BACKGROUND: Anthracycline drugs for cancer therapy often cause functional myocardial impairment even in relatively low doses. We investigated the left ventricular function in asymptomatic anthracycline-treated children by automatic border detection (ABD) to assess its clinical usefulness for unmasking latent anthracycline-induced myocardial damage. METHODS AND RESULTS: Thirty-four children (0.7 to 17.6 years old) during or after anthracycline chemotherapy (26 to 1100 mg/m2) for malignancy (Chemo group) were studied, and 40 children (2.8 to 15.6 years old) without cardiac involvement served as normal control subjects (Control group). All patients underwent complete echocardiographic examination, including M-mode, Doppler, and ABD. Conventional echocardiography disclosed no difference between groups with regard to ejection fraction and the ratio of early to late transmitral flow velocity. In marked contrast, an investigation using ABD revealed that the Chemo group appeared to have some anthracycline-induced myocardial damage. In the apical 4-chamber view, peak filling rate in the Chemo group [2.3+/-0.4 end-diastolic area (EDA)/s] was significantly lower than that in the Control group (3.1+/-0.5 EDA/s) (P<0.0001), and time to peak filling rate in the Chemo group (106+/-31 ms) was clearly prolonged compared with that in the Control group (74+/-22 ms) (P<0.0001). CONCLUSIONS: Echocardiographic ABD may be a sensitive and useful noninvasive approach for evaluating subclinical anthracycline cardiotoxicity.

Adolescent↗

PubMed1999

Synthesis and degradation of a 28-kDa pod storage protein in french bean (Phaseolus vulgaris) plants

Pod storage protein (PSP) accumulated in developing pods of French bean (Phaseolus vulgaris L.) plants, and increasing the PSP mRNA level by pod removal resulted in the enhancement of PSP accumulation in pods that formed later. Pod storage protein was detected in flowers, young leaves and young stem internodes in addition to pods. Accumulation of PSP and its mRNA was induced by sink-removal in an organ-specific manner. In addition, wounding induced PSP accumulation systemically in leaves. Methyl jasmonate did not induce PSP synthesis but enhanced the synthesis that was induced by wounding. In senescing pods, PSP was degraded, and degradation products with molecular masses of 20 and 17 kDa were detected in the pods. The amount of 20-kDa degradation product was greater than that of the 17 kDa product.

Journal Article↗