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Biomedical subjects

M Fukushima

Publications and source records attributed to M Fukushima.

At least 55 records · Page 3Linked to original sources

Potentiation of the sensitivity of renal cell carcinoma cells to TRAIL-mediated apoptosis by subtoxic concentrations of 5-fluorouracil.

Cytotoxic chemotherapy has shown little antitumour activity against renal cell carcinoma (RCC). Although immunotherapy is relatively effective against RCC, the response rate is approximately 20%. Therefore, there is an urgent need to increase this response rate. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo-2L) is one member of the tumour necrosis factor ligand family that selectively induces apoptosis of cancer cells. Since several cytotoxic anticancer drugs including 5-fluorouracil (5-FU) also mediate apoptosis, we reasoned that combined treatment of cancer cells with TRAIL and drugs might result in synergy and overcome the resistance of the cancer cell. This study has examined whether TRAIL can synergise with 5-FU in both cytotoxic and apoptotic assays against drug-resistant RCC cells. Cytotoxicity was determined by an 1-day microculture tetrazolium dye assay. Synergy was assessed by isobolographic analysis. Treatment of Caki-1 cells with TRAIL in combination with 5-FU resulted in a synergistic cytotoxic effect. Synergy was also achieved in freshly derived RCC cells from 3 patients. The enhanced cytotoxicity was obtained irrespective of the sequence of the treatment, but the highest cytotoxicity was observed when Caki-1 cells were treated with TRAIL and 5-FU simultaneously. The synergy achieved in cytotoxicity with TRAIL and 5-FU was shown to be due to apoptosis. The mechanisms responsible for the synergistic cytotoxicity and apoptosis were examined. Treatment of Caki-1 cells with 5-FU enhanced the expression of p53 and bax, but had no effect on the expression of bcl-2. Incubation of Caki-1 cells with TRAIL enhanced the intracellular accumulation of 5-FU and 5-fluoro-2'-deoxyuridine 5'-monophosphate (FdUMP). Treatment of Caki-1 cells with TRAIL downregulated the expression of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) modestly, and upregulated the expression of orotate phosphoribosyltransferase (OPRT). However, the expression level of thymidine phosphorylase (TP) was not affected by TRAIL. This study demonstrates that combined treatment of RCC cells with TRAIL and 5-FU overcomes their resistance. The sensitisation obtained with freshly isolated RCC cells required low subtoxic concentrations of 5-FU. These findings support the potential application in vivo of a combination of TRAIL and 5-FU in the treatment of TRAIL/5-FU-resistant RCC.

Antimetabolites, Antineoplastic↗

Enhancement of the antitumour activity of 5-fluorouracil (5-FU) by inhibiting dihydropyrimidine dehydrogenase activity (DPD) using 5-chloro-2,4-dihydroxypyridine (CDHP) in human tumour cells.

The purpose of this study was to evaluate the use of 5-chloro-2,4-dihydroxypyridine (CDHP), a potent inhibitor of dihydropyrimidine dehydrogenase (DPD), to enhance the antitumour activity of the fluoropyrimidines. In an in vitro study, CDHP did not influence cell proliferation by itself. However, CDHP did inhibit 5-fluorouracil (5-FU) degradation and enhanced 5-FU cytotoxicity in a concentration-dependent manner in two human tumour cell lines (MIAPaCa-2 and HuTu80) with relatively high basal DPD activity. CDHP exhibited a maximum effect at a molar ratio (CDHP:5-FU) of more than 0.2. However, CDHP did not have any effect on 5-FU cytotoxicity in the CAL27 tumour cell line, which has a relatively low basal DPD activity, even at concentrations where the DPD activity is almost completely inhibited. In an in vivo study, the maximal tolerable doses (MTD) of tegafur (FT) and a combination of FT and CDHP at a molar ratio of 1:0.4 (FT/CDHP) for nude mice were determined by oral administration for 14 consecutive days. After a single oral administration of either FT or FT/CDHP at the MTD, the 5-FU serum concentration-time profiles were almost the same for both treatment strategies. When nude mice bearing subcutaneous (s.c.) MIAPaCa-2 cells were treated with either FT or FT/CDHP at the MTD, the FT/CDHP treatment showed a significantly higher antitumour effect than the FT treatment (tumour growth inhibition: FT/CDHP, 51+/-12%; FT, 21+/-25%; P<0.05). However, the host-body weight suppression induced by FT/CDHP and FT was equivalent. These findings suggest that the combination of fluoropyrimidine and CDHP for the treatment of tumours with a high basal DPD elicits a greater antitumour effect than treatment with fluoropyrimidines alone and we suggest that CDHP inhibits the degradation of 5-FU in the tumour.

Animals↗

Cisplatin-induced in vivo differentiation of human embryonal carcinoma.

OBJECTIVE: To investigate the differentiation of embryonal carcinoma (EC) by cisplatin, and the underlying mechanism, as untreated metastases of nonseminomatous germ cell tumours rarely consist of fully differentiated mature somatic tissues, but such mature metastases are more common after various treatments, including chemotherapy. MATERIALS AND METHODS: The TTSC-3 human testicular EC line heterotransplanted into nude mice was used as a target. After treating tumour-bearing mice with intraperitoneal injections of varying doses of cisplatin, the histopathology of the tumours was assessed and various gene expressions in the tumours determined by cDNA-array technology. RESULTS: When cisplatin at 1 mg/kg/week was injected intraperitoneally into TTSC-3-bearing mice, there was no effect on tumour growth. However, injecting cisplatin at 5 mg/kg/week induced a marked regression of the tumour. In contrast, cisplatin at 3 mg/kg/week had a modest inhibitory effect on tumour growth and induced tumour dormancy. Histological examination showed that 5 weeks after injecting cisplatin (3 mg/kg/week), primitive mesenchymal-like cells increased, and 10 weeks afterward cartilage and well-developed glands (teratoma) were apparent; at > 15 weeks afterward there were no EC cells visible. cDNA probes from reverse-transcribed mRNAs of TTSC-3 treated with cisplatin or saline for 10 weeks were compared to identify genes differentially expressed in cisplatin-treated TTSC-3. Of 1176 different human cDNA transcripts in cisplatin-treated TTSC-3, three genes (tumour necrosis factor receptor 1, caspase 8 and Apaf1), which are associated with apoptosis, were expressed markedly more than after saline injection. CONCLUSIONS: The intermediate dose of cisplatin inhibited tumour growth of EC by inducing differentiation and enhancing apoptosis-related gene expression. These findings suggest that cisplatin may play a significant role in the differentiation of EC in vivo.

Animals↗

Partial agonistic activity of labetalol, the arylethanolamine, on beta 3-adrenoceptors in the guinea-pig gastric fundus.

1. The agonistic and antagonistic effects of labetalol, the alpha1- and beta-adrenoceptor antagonist, were studied on beta3-adrenoceptors in the guinea-pig gastric fundus. 2. Labetalol caused a concentration-dependent relaxation with a pD2 value of 5.58 +/- 0.09 and an intrinsic activity of 0.64 +/- 0.06, which was not affected by pretreatment with both the selective beta1-adrenoceptor antagonist, (+/-)-atenolol (100 microM), and the selective beta2-adrenoceptor antagonist, (+/-)-butoxamine (100 microM). 3. However, the non-selective beta1-, beta2- and beta3-adrenoceptor antagonist, (+/-)-bupranolol (3-30 microM), shifted the concentration-response curve of labetalol to the right (pA2 value=5.97 +/- 0.08). 4. In the presence of (+/-)-atenolol (100 microM) and (+/-)-butoxamine (100 microM), relaxations to catecholamines [(-)-isoprenaline, (-)-noradrenaline and (-)-adrenaline], to the selective beta3-adrenoceptor agonist, BRL37344, and to the non-conventional partial beta3-adrenoceptor agonist, (+/-)-CGP12177A, were weakly antagonized by labetalol (10 microM). 5. These results indicate that labetalol, the arylethanolamine, acts as a partial agonist on beta3-adrenoceptors in the guinea-pig gastric fundus.

Adrenergic beta-3 Receptor Agonists↗

Effect of short-term low-intensity exercise on insulin sensitivity, insulin secretion, and glucose and lipid metabolism in non-obese Japanese type 2 diabetic patients.

The aim of the present study was to investigate the effects of short-term physical exercise that did not change body mass on insulin sensitivity, insulin secretion, and glucose and lipid metabolism in 39 non-obese Japanese type 2 diabetic patients. Insulin sensitivity and insulin secretion were estimated with homeostasis model assessment insulin resistance (HOMA-IR) and HOMA-B-cell function proposed by Matthews et al., respectively. All patients were hospitalized and were engaged in low-intensity exercise that consisted of walking and dumbbell exercise for successive 7 days. There were no changes in hospital diet and the dose of any medications used throughout the study. Fasting glucose, insulin, and lipids were measured before and after exercise. After exercise, serum triglyceride levels significantly decreased, but no significant changes were observed in total and HDL cholesterol concentrations. Fasting glucose, insulin, and HOMA-IR levels significantly decreased after exercise, but HOMA-B-cell function did not change during the study. There was no significant difference between BMI levels before and after exercise. From these results, it can be concluded that short-term (7 days) low-intensity physical exercise combined with hospital diet reduces serum triglycerides, insulin resistance, and fasting glucose levels without affecting BMI in non-obese Japanese type 2 diabetic patients.

Adult↗

Observation of the decay B --> Kl+l-.

We report a search for the flavor-changing neutral current decay B-->K(*)l+l- using a 29.1 fb(-1) data sample accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- storage ring. We observe the decay process B-->Kl+l-(l = e, mu), for the first time, with a branching fraction of B(B-->Kl+l-) = (0.75(+0.25)(-0.21)+/-0.09)x10(-6).

Journal Article↗

Observation of B --> J/psi K(1)(1270).

We report the first observation of the exclusive decay process B-->J/psi K(1)(1270) using a sample of 11.2M BB macro meson pairs collected in the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. We measure branching fractions of B[B(0)-->J/psi K(0)(1)(1270)] = (1.30+/-0.34+/-0.32) x 10(-3) and B[B(+)-->J/psi K(+)(1)(1270)] = (1.80+/-0.34+/-0.39) x 10(-3), where the first error is statistical and the second is systematic. These modes constitute approximately 15% of the total number of B-->J/psi X decays. No evidence is seen for B-->J/psi K(1)(1400) and we set an upper limit for this branching fraction.

Journal Article↗

Degradation characteristics of humic acid during photo-Fenton processes.

Changes in the molecular and structural characteristics of humic acid (HA) during photo-Fenton processes were studied. When aqueous solutions at pH 5.0, which contained HA, Fe(III), and H2O2, were irradiated (lambda > 370 nm), the concentrations of total organic carbon (TOC) decreased with increasing irradiation time, indicating that a portion of the HA was mineralized to CO2 during this process. To investigate the changes in molecular and structural characteristics, the HA was reisolated from the reaction mixtures after each period of irradiation. The increased elution volumes required for isolation by gel permeation chromatography indicated that the molecular size of HA decreased as a result of the irradiation. In the FTIR spectra, ether and epoxide functional groups were identified, after irradiation. These products could be formed via radical coupling and/or via peroxy radical addition reactions to the unsaturated groups in the HA, such as vinyl and aromatic groups. Moreover, an analysis of structural fragments in HA by pyrolysis-GC/MS showed that the cinnamic acid moieties (CA) disappeared, as a result of irradiation. In the molecular weight fractionated HA, the majority of the iron species were complexed with the high molecular weight HA fraction, and the CA levels of the high molecular weight fraction were larger than those in the low molecular weight fraction. These results are consistent with residues, as the reactive sites in the photo-Fenton systems. Therefore, the degradation of these sites in the high molecular weight fraction may serve as a factor in decreasing the molecular size of HA.

Carbon Dioxide↗

Observation of Cabibbo suppressed B --> D(*)K- decays at Belle.

We report observations of the Cabibbo suppressed decays B-->D((*))K- using a 10.4 fb(-1) data sample accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring. We find that the ratios of Cabibbo suppressed to Cabibbo favored branching fractions are B(B--->D0K-)/B(B--->D0pi(-)) = 0.079+/-0.009+/-0.006, B(B(0)-->D+K-)/B(B(0)-->D+pi(-)) = 0.068+/-0.015+/-0.007, B(B--->D(*0)K-)/B(B--->D(*0)pi(-)) = 0.078+/-0.019+/-0.009, and B(B(0)-->D(*+)K-)/B(B(0)-->D(*+)pi(-)) = 0.074+/-0.015+/-0.006. These are the first observations of the B-->D+K-, D(*0)K-, and D(*+)K- decay processes.

Journal Article↗

Observation of large CP violation in the neutral B meson system.

We present a measurement of the standard model CP violation parameter sin2 phi(1) based on a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is fully reconstructed as a J/psi K(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psi K(L), or J/psi K(*0) decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2 phi(1) = 0.99+/-0.14(stat)+/-0.06(syst). We conclude that we have observed CP violation in the neutral B meson system.

Journal Article↗

Prognostic significance of thymidylate synthase activity in bladder carcinoma.

BACKGROUND: 5-fluorouracil (5-FU) is an anticancer agent clinically used against various cancers including bladder carcinoma. 5-FU inhibits thymidylate synthase (TS) and blocks DNA synthesis. TS is the key enzyme in the catalysis of the methylation from deoxyuridine monophosphate (dUMP) to deoxythymidine monophosphate. Little is known about the significance of TS in bladder carcinoma. The authors investigated the activity of TS in 82 bladder cancers and prognostic significance of the levels of TS and/or activities of dihydropyrimidine dehydrogenase (DPD), an important enzyme in the degradation of 5-FU. METHODS: The levels of TS and DPD activities in nonfixed, fresh, frozen, bladder carcinoma and normal bladder specimens were determined biochemically by the FdUMP binding assay and the 5-FU degradation assay, respectively. RESULTS: The activity of TS was 10-fold higher in bladder carcinoma compared with normal bladder. TS activity in muscle-invasive bladder carcinoma was threefold higher than that in Ta and T1 cancer. In addition, the activity of TS in T1 bladder carcinoma was threefold higher than that in Ta cancer. The level of TS activity in Grade 3 bladder carcinoma was 4.5-fold and 3.5-fold higher than that in Grade 1 and Grade 2 cancers, respectively. Patients with Ta and T1 bladder carcinoma with low TS activity had a longer postoperative tumor-free period than those with high activity in the 2-year follow-up. Patients with Ta and T1 bladder carcinoma with high or low TS activity were divided into four subgroups: high or low DPD activity subgroups. Patients with low TS activity and high DPD activity had the longest postoperative disease-free period among the 4 subgroups during the 2-year follow-up. CONCLUSIONS: To the authors' knowledge, the current study is the first study that demonstrated that the level of TS activity correlates with both the progression of the stage and the increase of the grade of bladder carcinoma and that elevated TS activity predicts early recurrence in Ta and T1 bladder carcinoma. These results suggested that elevated TS activity might have been associated with a higher chance of progression and recurrence of bladder carcinoma in the patients who participated in this study.

Adult↗

Dexamethasone prevents acute cadmium-induced hepatic injury but exacerbates kidney dysfunction in rabbits.

Cadmium is a potent hepatotoxicant for which neither effective preventive methods nor the mechanism of toxicity has been established. We investigated the preventive effect of dexamethasone against cadmium toxicity on cadmium-induced liver injury in rabbits. Pretreatment with dexamethasone at 1 mg/kg increased the rate of survival in rabbits administered 2.5 mg/kg iv cadmium. Cadmium induced acute severe liver injury characterized by hepatocellular necrosis, infiltration by inflammatory cells, and increases of plasma GOT, GPT, LDH, and LDH5. Dexamethasone mitigated the acute hepatotoxic effect of cadmium, but exacerbated cadmium-induced kidney dysfunction, with destruction of renal tubular cells and increases in excretion of protein, glucose, and amino acids into urine. The cadmium concentration in liver and kidney of rabbits administered cadmium was not changed by dexamethasone pretreatment. Although metallothionein mRNA expression induced by cadmium was not affected by dexamethasone in liver or kidney, cadmium-induced metallothionein protein production was augmented at the early phase in liver and decreased at the later phase in kidney. Neutrophilia observed after cadmium administration was enhanced initially by dexamethasone pretreatment. These results indicate that dexamethasone pretreatment potently prevented cadmium-induced liver injury, but exacerbated renal tubular dysfunction.

Amino Acids↗

Degradation pathways of pentachlorophenol by photo-Fenton systems in the presence of iron(III), humic acid, and hydrogen peroxide.

The degradation characteristics and pathways of pentachlorophenol (PCP) by the photo-Fenton systems were studied in H2O2 aqueous solutions, which contained Fe(III) only [H2O2/Fe(III) system] and Fe(III) + humic acid (HA) [H2O2/Fe(III)/HA system] at pH 5.0. Although 40% of the PCP was degraded after 5 h of irradiation in the H2O2/Fe(III) system, more than 90% was degraded in the H2O2/Fe(III)/HA system. This shows that at pH 5.0 the degradation of PCP is clearly enhanced by the presence of HA in the photo-Fenton system. In the H2O2/Fe(III) system, the production of octachlorodibenzo-p-dioxin (OCDD) was detected, and 2-hydroxy nonachlorodiphenyl ether was also identified as a precursor of OCDD. However, no OCDD production was observed in the H2O2/Fe(III)/HA system. This indicates that the presence of HA represses the production of OCDD during the degradation of PCP by the photo-Fenton system. Such an effect by HA can be attributed to a reaction sequence wherein reaction intermediates derived from PCP, such as PCP., are incorporated into HA. This was verified by 13C NMR and pyrolysis-GC/MS studies.

Biodegradation, Environmental↗

Stable operation of a 300-m laser interferometer with sufficient sensitivity to detect gravitational-wave events within our galaxy.

TAMA300, an interferometric gravitational-wave detector with 300-m baseline length, has been developed and operated with sufficient sensitivity to detect gravitational-wave events within our galaxy and sufficient stability for observations; the interferometer was operated for over 10 hours stably and continuously. With a strain-equivalent noise level of h approximately 5x10(-21)/sqrt[Hz], a signal-to-noise ratio of 30 is expected for gravitational waves generated by a coalescence of 1.4M-1.4M binary neutron stars at 10 kpc distance. We evaluated the stability of the detector sensitivity with a 2-week data-taking run, collecting 160 hours of data to be analyzed in the search for gravitational waves.

Astronomy↗

Fifty-seven-kDa protein in royal jelly enhances proliferation of primary cultured rat hepatocytes and increases albumin production in the absence of serum.

We have previously shown that 57-kDa protein in royal jelly (RJ) was specifically degraded in proportion to both storage temperature and storage period, and we suggested that it could be useful as a marker of freshness of RJ (Kamakura, M., Fukuda, T., Fukushima, M. and Yonekura, M. (2001) Biosci. Biotechnol. Biochem. 65, 277-284.). Here, we investigated the physiological effects of 57-kDa protein on primary cultured rat hepatocytes in the absence of serum. The 57-kDa protein and RJ significantly stimulated hepatocyte DNA synthesis, whereas bovine serum albumin and RJ stored at 40 degrees C for 7 days, which lacks 57-kDa protein, did not. The mitogenic activity of 57-kDa protein was lost after treatment with trypsin. These results indicate that 57-kDa protein acts as a mitogen. The stimulatory effect of 57-kDa protein was dose-dependent and was more potent at lower than at higher cell densities. The 57-kDa protein also prolonged the cell proliferation of primary cultured rat hepatocytes, with an enhancement of albumin production compared to untreated cells. Therefore, 57-kDa protein is likely to promote liver regeneration and may have a cytoprotective action on hepatocytes.

Albumins↗

Measurement of B(0)(d)-B_(0)(d) mixing rate from the time evolution of dilepton events at the upsilon(4S).

We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.

Journal Article↗