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Biomedical subjects

T Kubota

Publications and source records attributed to T Kubota.

At least 181 records · Page 10Linked to original sources
PubMed2000

PC-SPES: a unique inhibitor of proliferation of prostate cancer cells in vitro and in vivo .

BACKGROUND: Management of prostate cancer that has spread beyond the capsule is a difficult problem. Innovative and nontoxic approaches to the disease are urgently required. Recently, a commercially available herbal mixture called PC-SPES showed potent antitumor activities on a variety of malignant cells in vitro. METHODS: PC-SPES was evaluated for its ability to inhibit clonal growth, and to induce cell cycle arrest of three human prostate cancer cell lines (LNCaP, PC-3, and DU 145). Western blot analysis examined the effect of PC-SPES on levels of p21(waf1), p27(kip1), Bcl-2, and E-cadherin in the three cell lines; and telomerase activity was examined by telomeric repeat amplification protocol (TRAP) assay. Furthermore, the effect of oral PC-SPES (250 mg/kg/day) on growth of PC-3 and DU 145 tumors present in male BNX nu/nu triple immunodeficient mice was studied. LNCaP cells were not analyzed in mice because they grow only with difficulty in these immunodeficient mice. RESULTS: PC-SPES markedly inhibited clonal growth of LNCaP, PC-3, and DU 145 prostate cancer cells, with a 50% inhibition (ED50) at approximately 2 microl/ml. Pulse-exposure studies showed that a 5-day pulse-exposure to PC-SPES (2 microl/ml) in liquid culture achieved a 50% inhibition of PC-3 clonal growth in soft agar, suggesting that the growth inhibition mediated by the extracts remained after removal of PC-SPES. Cell cycle analysis using the prostate cancer cell lines found that PC-SPES induced a significant increase in the number of cells in G0-G1 and G2/M, with a concomitant decrease in the number of cells in S phase. PC-SPES (2 microl/ml, 4 days) increased slightly the levels of p21(waf1) in the three cell lines, decreased by 40% the levels of Bcl-2 in PC-3, and the levels of p27(kip1) and E-cadherin and telomerase were unchanged in each of the lines. In vivo treatment with oral PC-SPES of male BNX mice having DU 145 tumors produced significant inhibition of their growth (P < 0.001), with no objective side effects including blood chemistries, weights, or autopsy analysis. The PC-SPES showed no statistical effect on the in vivo growth of PC-3 cells. CONCLUSIONS: PC-SPES inhibits clonal proliferation of human prostate cancer cells both in vitro and in vivo, using a murine model.

Androgens↗
PubMed2000

Lack of differences in diclofenac (a substrate for CYP2C9) pharmacokinetics in healthy volunteers with respect to the single CYP2C9*3 allele.

OBJECTIVES: Evidence exists to suggest that diclofenac is metabolised by CYP2C9. The present study was undertaken in order to evaluate the effect of the single CYP2C9*3 variant on drug metabolism using diclofenac as a probe drug. METHODS: A single dose of diclofenac was administered orally to 12 healthy subjects in whom the genotype of CYP2C9 had been determined previously. The disposition kinetics of diclofenac were compared between homozygotes for the wild type (CYP2C9*1/*1, n = 6) and heterozygotes for the Leu359 variant (CYP2C9*1/*3, n = 6). RESULTS: For diclofenac, the following kinetic parameters were observed in the CYP2C9*1/*1 and CYP2C9*1/*3 subjects, respectively (mean +/- SD): apparent oral clearance (ml/kg/h) 355.8 +/- 56.9 and 484.4 +/- 155.3; area under plasma concentration time curve (microg h/ml) 2.7 +/- 0.7 and 1.9 +/- 0.6. The formation clearance of 4'-hydroxydiclofenac (ml/kg/h) was 63.6 +/- 19.1 in the CYP2C9*1/*1 subjects compared with 75.9 +/- 27.6 in the CYP2C9*1/*3 subjects. There were no significant differences in any of the kinetic parameters for either diclofenac disposition or formation clearance of 4'-hydroxydiclofenac between the two genotype groups. CONCLUSION: Since the disposition kinetics of diclofenac does not change in subjects with the single CYP2C9*3 mutant allele, it is suggested that the effects of CYP2C9 polymorphisms on the drug metabolism tend to be substrate specific.

Adult↗
PubMed2000

Alteration of the membrane lipid environment by L-palmitoylcarnitine modulates K(ATP) channels in guinea-pig ventricular myocytes.

Sarcolemmal adenosine 5'-triphosphate-sensitive K+ channels (K(ATP)) are dramatically up-regulated by a membrane phospholipid, phosphatidyl-inositol-4,5-bisphosphate (PIP2). During ischaemia, L-palmitoylcarnitine (L-PC), a fatty acid metabolite, accumulates in the sarcolemma and deranges the membrane lipid environment. We therefore investigated whether alteration of the membrane lipid environment by L-PC modulates the K(ATP) channel activity in inside-out patches from guinea-pig ventricular myocytes. L-PC (1 microM) inhibited KATP channel activity, without affecting the single channel conductance, through interaction with Kir6.2. L-PC simultaneously enhanced the ATP sensitivity of the channel [concentration for half-maximal inhibition (IC50) fell from 62.0+/-2.7 to 30.3+/-5.5 microM]. In contrast, PIP2 attenuated the ATP sensitivity (IC50 343.6+/-54.4 microM) and restored Ca2+-induced inactivation of KATP channels (94.1+/-13.7% of the control current immediately before the Ca2+-induced inactivation). Pretreatment of the patch membrane with 1 microM L-PC, however, reduced the magnitude of the PIP2-induced recovery to 22.7+/-6.3% of the control (P<0.01 vs. 94.1+/-13.7% in the absence of L-PC). Conversely, after the PIP2-induced recovery, L-PC's inhibitory action was attenuated, but L-PC partly reversed the PIP2-mediated decrease in the ATP sensitivity (IC50 fell from 310+/-19.2 to 93.1+/-9.8 microM). Thus, interaction between L-PC and PIP2 in the plasma membrane appears to regulate K(ATP) channels.

Adenosine Triphosphate↗
PubMed2000

Gastrointestinal stromal tumors treated by laparoscopic surgery: report of three cases.

Three cases of gastrointestinal stromal tumors (GIST) were treated by a laparoscopic wedge resection of the stomach. The tumor characteristics were confirmed to be nonepithelial, nonlymphomatous, nonmyogenic, and nonneurogenic gastrointestinal neoplasms with an uncertain origin which were CD34-positive and actin- and S-100-negative. The malignant potential was estimated based on the mitotic figures and growth rates. The results suggest that laparoscopic surgery is an adequate strategy for gastric submucosal tumors including GIST, and also indicates this technique to be a curative, safe, and minimally invasive procedure for both diagnosis and treatment.

Actins↗
PubMed2000

Jejunal limb obstruction caused by a cholesterol stone 15 years after a total gastrectomy and 20 years after a cholecystectomy: report of a case.

We present herein the rare case of a 74-year-old woman found to have jejunal limb obstruction caused by a cholesterol stone 15 years after a total gastrectomy with Roux-en-Y anastomosis, and 20 years after a cholecystectomy. The patient complained of repeated episodes of upper abdominal distress on three separate occasions over a period of 20 months, and jejunal limb obstruction was diagnosed by abdominal computed tomography scanning and (99m)Tc scintigraphy. Surgery revealed a stone incarcerated in the jejunal limb, where the anastomosis had become slightly stenotic. The removed stone was 3.5 cm in diameter and was subsequently demonstrated to be a cholesterol stone by chemical analysis. This report is thought to be the first to describe jejunal limb obstruction caused by a gallstone incarcerated in the jejunal limb after a total gastrectomy in a patient with a history of cholecystectomy.

Acute Disease↗
PubMed2000

Expression of matrix metalloproteinases in the chronic subdural haematoma membrane.

To study the role of matrix metalloproteinases (MMP) in the development of chronic subdural haematoma, we investigated the expression and activity of MMPs (MMP-1, -2, -3, -7 and -9) and tissue inhibitors of MMP (TIMP-1 and -2) in capsules of chronic subdural haematoma from 10 patients. Outer membranes of chronic subdural haematoma were immunostained for MMP-1, MMP-2, MMP-9, TIMP-1 and TIMP-2. Moreover, we confirmed MMP activity in membranes by SDS-PAGE zymography and in situ zymography. These results suggest that MMP degrades extracellular matrix in outer membranes of chronic subdural haematoma, which is thought to decrease their integrity followed by direct haemorrhage and exudation of oedematous fluid from membrane vessels into the haematoma cavity.

Adult↗
PubMed2000

Biomechanical study of gait using an intelligent brace.

We have developed a new long leg brace fitted with a computer-controlled knee joint that allows the user to go up and down a slope and stairs. Using this new brace, we analyzed gait under various conditions in ten normal men in terms of dynamic electromyography. Walking up a slope with normal step produced discharges in the leg muscles other than the gastrocnemius lateral head before and after the heel-strike on the ground, which indicated the absorption of the impact of landing. Going down a slope with controlled step resulted in lower activities of the tibialis anterior and the gastrocnemius lateral head than doing so with non-locked step or locked step. In subjects walking up stairs with tandem gait, the large discharges of the gastrocnemius lateral head that were observed in the late stance phase with normal step disappeared when the brace was applied. These results indicated that the muscle activity levels decreased during controlled walking with this new brace, and that the new brace can compensate for reduced muscle strength of the lower leg during walking. Kinematic analysis of walking revealed no significant difference between normal walking and controlled walking under any walking conditions.

Adult↗
PubMed2000

The role of the sentinel lymph node in gastrointestinal cancer.

Evaluation of the clinical significance of the sentinel node concept in GI cancer has just begun. The authors' preliminary data, using intraoperative radiation techniques and the gamma probe, suggest that it is worthwhile to continue the evaluation of this procedure to determine its role in an accurate staging and a minimally invasive approach to GI cancers.

Feasibility Studies↗
PubMed2000

Effect of an antioxidant, ebselen, on development of chronic cerebral vasospasm after subarachnoid hemorrhage in primates.

BACKGROUND: Oxidation and/or free radical reactions after subarachnoid hemorrhage (SAH) may be involved in the development of chronic cerebral vasospasm. The inhibition of these reactions is thought to be one of the therapeutic strategies for prevention of cerebral vasospasm. We investigated the effect of Ebselen, a synthetic seleno-organic compound, which exhibits anti-oxidation by glutathione peroxidaselike activity to inhibit free radical reactions by lipid peroxidation on the development of chronic cerebral vasospasm in a primate model. METHODS: Seventeen monkeys were used. SAH was produced by introduction of a blood clot around the right middle cerebral artery and the right side of the circle of Willis in all animals. The monkeys were randomly divided into three groups according to Ebselen dosage: 1) no dosage or non-treated group; 2) high-dose Ebselen group; and 3) low-dose Ebselen group. The drug was administered at 10 mg/Kg in the high-dose group and 5 mg/Kg in the low-dose group twice a day in each group for 7 days after SAH. The vessel diameter was evaluated on angiograms before the induction of SAH and at Day 7 following SAH. RESULTS: In the untreated group, the angiograms showed significant (p < 0.05) reductions of the mean vessel caliber of the right internal carotid (ICA) (38 +/- 10% reduction) and the middle cerebral artery (MCA) (56 +/- 9.7%) compared with the baseline value before SAH. In the high-dose Ebselen-treated group, the mean percent reduction in vessel caliber of the right ICA (16 +/- 11%) and MCA (28 +/- 9.5%) on Day 7 angiograms were significantly (p < 0.05) lower than those in the nontreated group, whereas the mean percent reduction of these vessels in the low-dose Ebselen-treated group showed no significant difference compared with the untreated group. CONCLUSIONS: Chronic cerebral vasospasm was inhibited in the animals in which a relatively large amount of Ebselen was administered for 7 days after SAH. The results suggest that the oxidation or free radical reaction by lipid peroxidation after SAH might be involved in the pathogenesis of vasospasm, and that inhibition of these reactions by drugs, such as Ebselen, may have a promising effect for prevention of vasospasm.

Animals↗
PubMed2000

Radiosensitivity of human pancreatic cancer cells in vitro and in vivo, and the effect of a new hypoxic cell sensitizer, doranidazole.

BACKGROUND AND PURPOSE: A clinical study of the new 2-nitroimidazole nucleoside analogue doranidazole (PR-350) in combination with intraoperative radiotherapy is ongoing in Japan for localized unresectable pancreatic cancer. However, few data have been reported on the radiosensitivity and hypoxic fraction of human pancreatic cancers, and the efficacy of doranidazole against them. This study was undertaken to address these issues. MATERIALS AND METHODS: In vitro, four established human pancreatic cancer cell lines (SUIT-2, PANC-1, MIA PaCa-2 and BxPC-3) and murine SCCVII tumor cells (for comparison) were used. These cells were treated with 0.4 or 1 mM doranidazole for 45 mm prior to and during aerobic or hypoxic irradiation, and the cell survival was determined using the colony assay. In vivo, Balb/c nude mice bearing the pancreatic cancers (about 200 mg) on their backs received whole-body irradiation either after cervical dislocation, without physical restraint or anesthesia, or 20 min after intravenous injection of 100 mg/kg (0.4 mmol/kg) or 250 mg/kg (1 mmol/kg) of doranidazole. Following irradiation, the in vivo-in vitro assay was performed. The hypoxic fraction was estimated by the paired survival curve method. RESULTS: Regarding in vitro radiosensitivity, there were no characteristics common to the four pancreatic cancer cell lines. In vitro, doranidazole had no sensitizing effect under aerobic conditions, but under hypoxic conditions, its sensitizer enhancement ratio (SER) was 1.25-1.3 at 0. 4 mM and 1.4-1.55 at 1 mM against the four pancreatic cancer cell lines. These SERs were similar to those obtained in SCCVII cells. In vivo, the hypoxic fraction was 20% (95% CI, 11-38%) in SUIT-2, 14% (6.5-28%) in PANC-1, 10% (5.9-16%) in MIA PaCa-2, and 27% (15-46%) in BxPC-3 tumors. The SER of doranidazole was 1.15-1.3 at the dose of 100 mg/kg and 1.35-1.45 at 250 mg/kg. CONCLUSIONS: The four xenografted human pancreatic cancers had hypoxic fractions of 10-27% (mean: 18%). Doranidazole had definite in vitro and in vivo effects on all pancreatic cancer cell lines.

Animals↗
PubMed2000

Melanoma in situ of the penis.

Melanoma of the penis is rare and the prognosis is very poor. We report a case of melanoma in situ localized on the penile shaft. Melanoma in situ of the penis is extremely rare. We emphasize that early diagnosis of melanoma in situ will improve the prognosis of melanoma of the penis.

Dermatologic Surgical Procedures↗
PubMed2000

Probable involvement of a germ-line mutation of an unknown mismatch repair gene in a Japanese Muir-Torre syndrome phenotype.

A combination of haplotype analysis and direct sequencing were conducted on Japanese Muir-Torre syndrome kindred. In the kindred, two females revealed a hereditary non-polyposis colon cancer (HNPCC) phenotype and one male had a sebaceous tumor in addition to a HNPCC phenotype. Haplotype analysis and direct sequencing failed to show involvement of the known mismatch repair genes, with the exception of MSH5, in this kindred. Analysis of large fragments (from 3.9 to 6. 2 kb) covering the entire 25 kb MSH5 gene in the proband revealed the absence of gross changes in the promoter region and exons. The direct sequencing of the promoter region and all 25 exons failed to demonstrate any mutations in the coding regions except for a CA repeat polymorphism in intron 3 and a C/A polymorphism in intron 15. Taken together present results indicate that a novel and yet unknown mismatch repair gene is likely involved in the HNPCC in this kindred.

Adult↗
PubMed2000

Expression of proinflammatory cytokines in the failing human heart: comparison of recent-onset and end-stage congestive heart failure.

BACKGROUND: Plasma levels of proinflammatory cytokines, including tumor necrosis factor (TNF)-alpha and interleukin (IL)-6, are elevated in patients with congestive heart failure (CHF). Recent studies suggest that the failing human heart is a source of proinflammatory cytokines in the end-stage failing heart. However, the relevance of plasma levels to those of the myocardium remains undefined. We sought to compare cytokine expression in early and end-stage CHF, and to evaluate the correlation of tissue expression to plasma levels. METHODS: Two patient populations were studied: patients with recent-onset CHF, all with symptoms less than 6 months (n = 17, duration of symptoms 2.1 +/- 1.6 months, range of New York Heart Association (NYHA) 1 to 3), and end-stage heart-failure patients (n = 7) who underwent left-ventricular assist-device (LVAD) implantation (Duration of symptoms 47.1 +/- 28.0 months, all NYHA class 4). Plasma levels of TNF-alpha and IL-6 proteins were evaluated by an Enzyme-Linked Immuno-Sorbent Assay (ELISA), while myocardial levels of cytokine transcripts were assessed by ribonuclease (Rnase) protection assay. RESULTS: In patients with end-stage heart failure, TNF-alpha and IL-6 were increased in the plasma as well as in the myocardium (plasma: TNF-alpha = 7.7 +/- 2.3 pg/ml, IL-6 = 45.0 +/- 47.1 pg/ml; myocardium: TNF-alpha = 0.31 +/- 0.15% of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) expression, IL-6 = 1.56 +/- 1.54% ). In contrast, despite elevated plasma levels of TNF-alpha and IL-6, the myocardium of patients with the recent onset of symptoms demonstrated minimal expression of TNF-alpha and IL-6 messenger ribonucleic acid (mRNA) (plasma: TNF-alpha = 4.3 +/- 1.7 pg/ml, IL-6 = 3.3 +/- 1.8 pg/ml; myocardium: TNF-alpha = 0.13 +/- 0. 04%, IL-6 = 0.02 +/- 0.04%). Plasma levels of TNF-alpha were significantly correlated with those in the myocardium when both populations were combined. (r = 0.69, p < 0.001). CONCLUSIONS: Cytokines are expressed in the myocardium in end-stage heart failure to a much greater degree than in patients with the recent-onset of symptoms. This suggests that induction of cytokines in the myocardium is a relatively late event in the pathogenesis of CHF. Furthermore, plasma levels of TNF-alpha correlates with mRNA expression in the myocardium and thus may serve as an appropriate marker of myocardial cytokine activation. Whether the production of cytokines in the failing human heart precedes the elevation of cytokines in the plasma remains undefined. Therefore, we studied expression of TNF-alpha and IL-6 in the myocardium as well as in the plasma in patients with early and end-stage CHF. The results have demonstrated that cytokines are expressed in the myocardium in end-stage heart failure to a much greater degree than in patients with the recent onset of symptoms. This suggests that induction of cytokines in the myocardium is a relatively late event in the pathogenesis of CHF.

Adult↗
PubMed2000

The expression and activation of matrix metalloproteinase-2 in rat brain after implantation of C6 rat glioma cells.

It has been reported that matrix metalloproteinases (MMPs) are highly expressed in malignant glioma cells and that this increased expression may facilitate the invasiveness of tumor cells. The authors investigated the expression and enzymatic activity of MMPs in rat brain during the growth of malignant gliomas at different time intervals. C6 rat glioma cells were unilaterally implanted into rat cerebral hemispheres. After 7 or 14 days, these brain tissues were prepared for SDS-PAGE zymography, Western blotting, immunohistochemistry, and in situ zymography. SDS-PAGE zymography and Western blotting revealed that the expression of proMMP-2 in rat brains with C6 glioma cells was significantly higher than that in normal or the sham-operated rat brains, and that the activated form of MMP-2 was detected only in the former but not in the latter. On immunohistochemistry, C6 glioma cells presenting invasive growth into the rat brain parenchyma and vessels demonstrated MMP-2 immunoreactivity. On in situ zymography, foci of invasive C6 glioma cells in rat brain tissue showed gelatinolytic activity. These results suggest that expression and activation of MMP-2 may be one of the crucial steps for glioma cell invasion into the brain parenchyma in vivo.

Animals↗
PubMed2000

Matrix metalloproteinase expression in cultured human gastric wall fibroblasts--interactions with Helicobacter pylori isolated from patients with ulcers.

BACKGROUND: Matrix metalloproteinases (MMPs), enzymes capable of degrading collagens and other extracellular matrix components, have been implicated in gastric ulcer formation. However, the effect on MMP expression of Helicobacter pylori, also implicated in these lesions, has not been studied to our knowledge. AIM: To seek links between H. pylori and MMP expression likely to affect gastric ulcer formation. After fibroblasts from human gastric wall were cocultured with H. pylori. concentrations of MMP-1 and -2 in the medium were determined by enzyme-linked immunosorbent assays. RESULTS: Whereas MMP-1 was not detected in media from fibroblasts or H. pylori culture alone, MMP-1 was detected in cocultures (P<0.01). Similar amounts of MMP-2 were detected in medium from fibroblasts cultured alone and with H. pylori. No MMP-2 production by H. pylori cultured alone was detected. CONCLUSIONS: MMP-1 appears to be important in gastric ulcer pathogenesis, and MMP-1 induction by H. pylori may impede gastric ulcer healing.

Cells, Cultured↗
PubMed2000

Frequencies of CYP2D6 mutant alleles in a normal Japanese population and metabolic activity of dextromethorphan O-demethylation in different CYP2D6 genotypes.

AIMS: To determine the frequencies of 11 CYP2D6 mutant alleles (CYP2D6*2, *3, *4, *5, *8, *10, *11, *12, *14, *17 and *18), and their relation to the metabolic capacity of CYP2D6 in Japanese subjects. METHODS: One hundred and sixty-two unrelated healthy Japanese subjects were genotyped with the polymerase chain reaction amplification method and 35 subjects were phenotyped with dextromethorphan. RESULTS: The frequencies of CYP2D6*2,*5, *10 and *14 were 12.9, 6.2, 38.6 and 2.2% in our Japanese subjects, respectively. CYP2D6*3, *4, *8, *11, *12, *17 and *18 were not detected. The mean log metabolic ratio of dextromethorphan in subjects with genotypes predicting intermediate metabolizers was significantly greater than that of heterozygotes for functional and defective alleles. CONCLUSIONS: CYP2D6*5 and CYP2D6*14 are the major defective alleles found in Japanese subjects. In addition, CYP2D6*10 may play a more important role than previously thought for the treatment of Japanese patients with drugs metabolized by CYP2D6.

Adult↗