Biomedical subjects

Kohsuke Uchida

Publications and source records attributed to Kohsuke Uchida.

15 recordsLinked to original sources

PubMed2006

Buthionine sulfoximine causes endothelium dependent hyper-relaxation and hypoadiponectinemia.

A close relationship between oxidative stress, endothelial dysfunction, and hypoadiponectinemia has been observed. The present study was performed to investigate how glutathione depletion via buthionine sulfoximine (BSO) administration affects endothelial function and adiponectin levels in rats. Acetylcholine (Ach)-induced vasodilation was significantly enhanced in BSO-treated rats, compared with control rats. This was completely abolished by L-NAME, and Ach-induced vasodilation was not observed in the aorta without endothelium. These results suggest that Ach-induced hyper-relaxation of the aorta in BSO-treated rats is completely dependent on the presence of endothelium and mediated by changes in eNOS activity. Catalase significantly inhibited this relaxation to Ach and no effect of catalase on sodium nitroprusside-induced relaxation of the aorta without endothelium was observed in BSO-treated rats. Thus, hyper-relaxation of the aorta in BSO-treated rats is likely caused by H2O2 in addition to NO produced by the endothelium via an eNOS-dependent mechanism. Hypoadiponectinemia and decreased levels of adiponectin mRNA in adipose tissue were observed in BSO-treated rats. Protein expression of eNOS and SODs (SOD-1 and SOD-2) in the aorta was increased and plasma NOx levels were decreased in BSO-treated rats. Our results suggest that oxidative stress induced by BSO causes eNOS uncoupling and hyper-relaxation by producing H2O2, and that BSO-induced oxidative stress causes hypoadiponectinemia, probably by increasing H2O2 production in adipose tissue.

Adiponectin↗

PubMed2006

Tetrahydrobiopterin prevents endothelial dysfunction and restores adiponectin levels in rats.

Oxidative stress induces endothelial dysfunction and hypoadiponectinemia. We previously reported that supplementation with tetrahydrobiopterin (BH4), one of the most potent naturally occurring reducing agents and an essential cofactor of enzymatic NO synthase (NOS), ameliorates endothelial dysfunction and reverses hypoadiponectinemia as a result of oxidative stress in rats. To further confirm this hypothesis, we investigated the effects of treatment with BH4 on endothelium-dependent relaxation and adiponectin levels during oxidative stress in fructose-fed rats, which provide an animal model for the metabolic syndrome. Ingestion of a fructose diet for 8 weeks significantly impaired endothelium-dependent arterial relaxation in aortic strips and decreased plasma adiponectin levels, as well as adiponectin mRNA levels within adipose tissue. However, oral supplementation with BH4 (10 mg/kg day) over the final 4 weeks leads to a significant partial reversal of impaired endothelium-dependent arterial relaxation, as well as normalization of plasma adiponectin and fat adiponectin mRNA levels. Moreover, BH4 treatment of the fructose-fed rats significantly reduced the lipid peroxidation content of aorta, heart, liver, and kidney tissues, which were increased in fructose-fed rats. This effect of BH4 treatment may be due to its function as a cofactor for eNOS, as well as its anti-oxidative effects. Thus, BH4 might show promise for the treatment of oxidative stress-induced disorders, including the metabolic syndrome.

Adiponectin↗

PubMed2006

The suppressant effect of GEA3162 on spontaneous serotonin release from human colonic mucosa in vitro.

The effect of a lipophilic nitric oxide (NO)-releasing compound 5-amino-3-(3,4-dichlorophenyl) 1,2,3,4-oxatriazolium (GEA3162) on the spontaneous release of 5-hydroxytryptamine (5-HT) from human colonic mucosa was investigated in vitro. In the presence of tetrodotoxin, spontaneous outflow of 5-HT from the human colonic mucosa was measured by high-performance liquid chromatography with electrochemical detection. GEA3162 concentration-dependently suppressed the 5-HT outflow, but neither the NO-activated soluble guanylate cyclase inhibitor 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) nor peroxynitrite scavenger ebselen affected the suppressant effect of GEA3162. Moreover, neither the L-type calcium channel blocker nicardipine, NO synthase inhibitor l-N(G)-nitroarginine methyl ester nor guanylate cyclase activator guanylin affected the spontaneous 5-HT outflow. These results indicate that human colonic mucosa is capable of eliciting tetrodotoxin-resistant and nicardipine-insensitive 5-HT release, and that GEA3162 can suppress the 5-HT release via an action on colonic mucosa through mechanism independent of ODQ-sensitive cyclic GMP system or peroxynitrite generation.

Calcium Channel Blockers↗

PubMed2006

Murine androgen-independent neuroendocrine carcinoma promotes metastasis of human prostate cancer cell line LNCaP.

BACKGROUND: Although neuroendocrine (NE) cells in prostate cancer have been speculated to accelerate the growth and progression of surrounding cancer cells, the evidence is as yet inconclusive. We investigated the effect of an NE allograft (NE-10) and its cell line, NE-CS, which were established from the prostate of the LPB-Tag 12T-10 transgenic mouse, on human prostate cancer cell line LNCaP. METHODS: The proliferation and pulmonary metastasis of LNCaP xenografts in athymic mice with and without NE-10 allografts were evaluated. Boyden chamber assay and microarray analysis were performed to investigate changes in invasion/migration and mRNA of LNCaP cells under the influence of the NE cells, respectively. RESULTS: NE-10 did not influence the proliferation of LNCaP. The pulmonary metastasis of LNCaP with NE-10 significantly increased compared to mice without it. The NE-CS cells accelerated the in vitro invasion/migration of adenocarcinoma cells. Increased expression of mRNA of gelsolin was observed in LNCaP cells incubated with the supernatant of NE-CS cells. CONCLUSIONS: The NE-10 allograft promotes pulmonary metastasis of subcutaneously inoculated LNCaP cells by facilitating cell invasion. Secretions from NE cells upregulate the expression of gelsolin, which is an actin-binding protein, resulting in acceleration of the migration of LNCaP cells.

Adenocarcinoma↗

PubMed2006

Aldosterone impairs vascular endothelial cell function.

Aldosterone is a mineralocorticoid hormone that plays an important role in regulating electrolyte balance and blood pressure and also participates in endothelial dysfunction. We evaluated the direct effect of aldosterone on human umbilical vein cells (HUVEC). Levels of eNOS phosphorylation by vascular endothelial growth factor were diminished, and the amount of NO produced in response to vascular endothelial growth factor measured as NO2+NO3 was significantly decreased in cells previously incubated with aldosterone. Incubation with aldosterone for 24 h dose-dependently increased Nox4 mRNA expression in HUVEC. Although NF-kappaB was not apparently activated by aldosterone, mRNA levels of vascular cell adhesion molecule-1, E-selectin, monocyte chemotactic protein-1, and intercellular adhesion molecule-1 in HUVEC were significantly increased after incubation with aldosterone. Thus, aldosterone directly causes the dysregulation of endothelial cell function, which may be partly responsible for high blood pressure and atherosclerosis.

Aldosterone↗

PubMed2005

Characterization of prostatic neuroendocrine cell line established from neuroendocrine carcinoma of transgenic mouse allograft model.

BACKGROUND: The role of neuroendocrine (NE) cells in prostate cancer remains unclear. A useful model is necessary to study the biology of NE cells. We herein describe the establishment and characterization of an immortalized cell line from an NE-10 allograft of murine prostatic NE carcinoma. METHODS: A novel cell line, designated NE-CS, was developed from an NE-10 allograft that was established from the ventral prostate of the LPB-T-antigen (Tag) transgenic mouse, line 10 (12T-10). We investigated the growth, karyotype, electron microscopic findings, expression of Tag and androgen receptor (AR), and tumorigenesis of the cells in athymic mice. RESULTS: The immortal cell line NE-CS was maintained in vitro for more than 2 years. The NE-CS cells had dendritic-like extensions with dense core granules in the cytoplasm and produced serotonin and somatostatin in conditioned medium. The cells expressed neither Tag nor AR. They showed androgen-independent growth in vitro and a hypotetraploid karyotype similar to the original NE-10 allograft. The NE-CS cells, which were subcutaneously inoculated into athymic mice, formed tumors with the NE phenotype. The tumors exhibited accelerated growth compared to the original NE-10 allograft. CONCLUSIONS: The established cell line has characteristics of NE differentiation and tumorigenic ability. This cell line may be a promising model to understand the molecular mechanisms associated with the acquisition of hormone refractory prostate cancer.

Animals↗

PubMed2005

Ligands for peroxisome proliferator-activated receptor gamma have potent antitumor effect against human renal cell carcinoma.

OBJECTIVES: To examine whether peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed in human renal cell carcinoma (RCC) cells, and whether activation of PPARgamma by its ligands can have multiple antitumor effects on human RCC cells in vitro. METHODS: We examined the expression of PPARgamma in four human RCC cell lines by reverse transcriptase-polymerase chain reaction and immunocytochemical staining. The effects of two PPARgamma ligands, pioglitazone and 15-deoxy-Delta12,14-prostaglandin J2, on cell proliferation were investigated by 3-[4,5-dimethylthiazol-2-thiazoly]-2,5-diphenyltetrazolium bromide assay. The induction of apoptosis by the ligands was examined using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling method and Annexin V assay. Furthermore, we investigated whether these ligands suppressed the production of angiogenic factors, vascular endothelial growth factor and basic fibroblast growth factor, by enzyme-linked immunosorbent assay. RESULTS: PPARgamma and retinoid X receptor, which forms a heterodimer with PPARgamma, were expressed in all RCC cell lines. In addition, immunocytochemical studies showed expression of PPARgamma protein in the RCC cells. PPARgamma ligands inhibited the cell growth in all cells in a dose-dependent manner. These ligands also induced apoptosis. Furthermore, secretion of both vascular endothelial growth factor and basic fibroblast growth factor was inhibited by these ligands in a dose-dependent and time-dependent manner. CONCLUSIONS: Ligands for PPARgamma have multiple antitumor effects in human RCC cells in vitro. Activation of the PPARgamma pathway may be a new strategy for treatment of patients with RCC.

Carcinoma, Renal Cell↗

PubMed2005

Supplementation with tetrahydrobiopterin prevents the cardiovascular effects of angiotensin II-induced oxidative and nitrosative stress.

OBJECTIVE: The pteridine cofactor tetrahydrobiopterin (BH4) has emerged as a critical determinant of endothelial nitric oxide synthase (eNOS) activity. When BH4 availability is limited, eNOS does not produce nitric oxide (NO) but instead generates superoxide. BH4 may reverse endothelial dysfunction due to cardiovascular disease, including atherosclerosis, coronary artery disease and hypertension. In this study, the influence of BH4 on cardiovascular parameters and the production of free radicals following angiotensin II (Ang II) infusion was assessed. METHODS: BH4 (20 mg/kg per day in drinking water) was administered with Ang II (300 ng/kg per min subcutaneously, osmotic pump) for 7 days in Sprague-Dawley rats. In addition, BH4 was also given in vehicle-infused rats. RESULTS: Treatment with BH4 significantly prevented some of the effects of Ang II, such as impaired vascular responses to acetylcholine, hypertension and increases in heart weight index values. Treatment with BH4 also significantly reduced Ang II-induced increases in inducible NO synthase expression, nitrotyrosine immunostaining, NO production and superoxide anion formation in rats. CONCLUSION: These results indicate that BH4 might prevent the development of hypertension and myocardial hypertrophy, as well as the Ang II-induced production of superoxide and NO, thereby reducing the production of peroxynitrite. Therefore, BH4 may protect against the cardiovascular manifestations of oxidative and nitrosative stress in this experimental model of Ang II-mediated hypertension.

Acetophenones↗

PubMed2005

Epithelium-dependent and -independent inhibitory effects of sivelestat, a neutrophil elastase inhibitor, on substance P-induced contraction of airway smooth muscle in lipopolysaccharide-treated guinea-pigs.

The underlying mechanism involved in the interaction between neutrophil elastase inhibitors and tachykinins has not been elucidated. In this study we have examined the effects of sivelestat, a neutrophil elastase inhibitor, on the in vitro responses of airways from lipopolysaccharide (LPS)-untreated or -treated guinea-pigs to substance P. Substance P (0.01-30 micromol/l) produced concentration-dependent contractions of both tracheal and bronchial ring preparations of LPS-untreated or -treated guinea-pigs. Responsiveness to substance P in these isolated airway preparations was augmented by either epithelium removal or LPS treatment. In epithelium-intact tracheal ring preparations isolated from LPS-untreated guinea-pigs, sivelestat (100 micromol/l) significantly inhibited substance P-induced contractions. The inhibitory action was markedly attenuated by pretreatment with L-NAME (100 micromol/l) or indomethacin (2 micromol/l), and was almost undetected following removal of the epithelium. On the other hand, in bronchial ring preparations isolated from LPS-untreated guinea-pigs, sivelestat had only a very slight effect on substance P-induced contraction of the epithelium-intact preparation, whereas sivelestat greatly inhibited contraction in epithelium-removed bronchial ring preparations. In LPS-treated guinea-pigs, whether the epithelium was intact or not, sivelestat significantly inhibited the substance P-induced contraction of bronchial ring preparations. Pretreatment with L-NAME (100 micromol/l) or indomethacin (2 micromol/l) did not affect the inhibitory effect of sivelestat in bronchial ring preparations. In conclusion, epithelium removal or LPS treatment induced hyperreactivity to substance P in the guinea-pig airway. Sivelestat caused epithelium-, nitric oxide- and prostaglandin-dependent inhibition of the substance P-induced contraction of isolated guinea-pig tracheal ring preparations. In contrast, the inhibitory effect of sivelestat on substance P-induced contraction of guinea-pig bronchial ring preparations is mediated by epithelium-, nitric oxide- and prostaglandin-independent mechanisms. Sivelestat may be effective in reducing the airway hyperresponsiveness to tachykinins induced by epithelial injury as occurs in LPS-mediated inflammatory lung diseases.

Animals↗

PubMed2005

[Network for the collection and distribution of Japanese liver tissues resected surgically for drug development and research use].

We focused on the establishment of a trial procedure for the collection and distribution of Japanese liver tissues obtained from waste surgical resections for drug development and research use. The following procedures were prepared for this project: the pretreatment of liver tissues before storage, their storage at 4 degrees C, the transport of liver samples, the setting up of a communication network among the participating hospitals and laboratories and the approval of each ethics committee. Thirteen liver samples (1.6-7.6 g) obtained from patients whose livers were excised due to cirrhosis, hepatocellular carcinoma, cholangiocarcinoma, or metastasis from colorectal carcinoma and were donated for research. Informed consent was obtained from every patient. Freshly isolated human hepatocytes were prepared from nine liver samples (viability 34.3-86.1%). Four samples were unsuitable to prepare hepatocytes. The profile of testosterone metabolism as 6beta-, 2beta-, 16beta-, 16alpha- and 2alpha-hydroxytestosterone and androstenedione in freshly isolated hepatocytes was shown to be specific for human liver. The 6beta-hydroxylation activity catalyzed by CYP3A4/5 indicated a high level of metabolism (139-996 pmol/min/million cells). Levels of 7-ethoxycoumarin O-deethylation and glucronidation activities were sufficient for analysis in freshly isolated human hepatocytes. We conclude that liver tissues from waste surgical resections supplied from a participating hospital can constitute a valuable source of freshly isolated human hepatocytes for drug development and safety evaluation.

Aged↗

PubMed2004

Preservative solution for freeze-storage of surgically excised human colon to enable study of smooth muscle function in vitro.

We have compared the reactivity to carbachol and high potassium of circular smooth muscle isolated from segments of human colon which was freeze-stored in different preservative solutions for more than one month following surgical resection. Concentration-dependent contractions in response to carbachol were reduced in terms of both their sensitivity (pEC50) and reactivity (Emax), depending on the preservative solutions used. Similar reduction of reactivity to 100 mM KCl was also observed. The best responsiveness was shown when the tissue was freeze-stored in SFM101. It is concluded that the freeze-storage of surgically excised human colon in SFM101 or phosphate buffer solution for more than one month provided the best preservation of smooth muscle function for in vitro pharmacological examination.

Aged↗

PubMed2004

Partial nephrectomy for small localized renal cell carcinoma.

We retrospectively reviewed the records of 54 patients with RCC who underwent partial nephrectomy for the primary lesion between 1992 and 2001. The indications for partial nephrectomy were elective in 43 and imperative in 11 patients. We selected 51 patients with clinical stage T1a who underwent open radical nephrectomy for localized RCC for comparison during the same period. We evaluated the peri- and postoperative complications, disease-free survival rates and changes of renal function in the partial nephrectomy (PN) group, compared to the radical nephrectomy (RN) group. There was no significant difference with regard to pathological findings and clinical outcomes between two groups, except for the amount of intraoperative bleeding. Three patients in the PN group developed postoperative complications, consisting of urine leakage in 2 patients and renal hypertension in 1 patient. The 5-year disease-free survival rates in the PN and RN groups were 90% and 97%, respectively. Local recurrence from the resected area of the renal parenchyma was not found in patients in the PN group. All patients in the PN group maintained satisfactory and stable renal function. In the RN group, renal function slowly deteriorated in 2 patients. Therefore, partial nephrectomy offers cancer control and an acceptable low mortality rate, comparable to those of radical nephrectomy.

Adult↗

PubMed2003

Testicular metastasis from squamous cell carcinoma of the lung.

We present a case of squamous cell carcinoma of the testis that metastasized from lung cancer. The patient, who had received left pneumonectomy 2 years earlier for squamous cell carcinoma (SCC) of the lung, developed pulmonary metastasis, which was treated with chemotherapy. Although the recurrence regressed after treatment, the testicular tumor progressed gradually. Left radical orchiectomy was performed. Pathological examination revealed metastatic SCC. Testicular metastasis from lung cancer is a very rare disease.

Carcinoma, Squamous Cell↗

PubMed2002

Recurrence of renal cell carcinoma more than 5 years after nephrectomy.

OBJECTIVES: We evaluated clinical features and predictive factors for the recurrence of renal cell carcinoma (RCC) developing more than 5 years after nephrectomy. METHODS: We retrospectively reviewed 239 patients with RCC who underwent surgery for the primary lesion. To identify factors that affected recurrence more than 5 years after nephrectomy (delayed recurrence) and its clinical outcomes, we performed a multivariate analysis using Cox's proportional hazards model and a survival study. RESULTS: Recurrence developing within 5 years after nephrectomy (early recurrence) was found in 57 patients and delayed recurrence in 11 patients. The multivariate analysis revealed no clinical and pathologic features influencing delayed recurrence in 114 patients who survived more than 5 years after nephrectomy without having early recurrence. The patients with delayed recurrence showed better clinical outcomes than those with early recurrence when the rate was determined from the time of recurrence. CONCLUSIONS: Although delayed recurrence is not a rare event for patients with RCC, no clinical and pathologic factors at the time of the initial treatment can predict the recurrence. Patients who are free of recurrence for more than 5 years after surgery for a primary lesion should be carefully followed up for delayed recurrence.

Adult↗

PubMedDate not supplied

Comparison of motor reactivity of the colonic muscularis mucosae isolated from human, guinea pig and rat in vitro.

We have compared the reactivity to spasmogens of longitudinal muscularis mucosae isolated from the human, guinea pig and rat colon in vitro. The muscularis mucosae isolated from the human distal colon responded with a sustained contractions to carbachol (10 nM-30 microM), in a concentration-dependent manner, and the maximum contraction was comparable to that with high potassium concentration (100 mM). Among several spasmogens, neurokinin A was the most potent with the following order of potency: carbachol, prostaglandin F2alpha and acetylcholine. Histamine, 5-hydroxytryptamine and bradykinin did not produce a recognizable contraction of this tissue. The muscularis mucosae isolated from the guinea pig distal colon demonstrated a concentration-dependent contraction in response to neurokinin A, carbachol, histamine and acetylcholine, but not to prostaglandin F2alpha or 5-hydroxytryptamine, and the maximum contraction was obtained with histamine. The muscularis mucosae from the rat distal colon was very sensitive to neurokinin A and bradykinin, less to carbachol and acetylcholine, and not at all sensitive to histamine, 5-hydroxytryptamine and prostaglandin F2alpha. It is concluded that the colonic muscularis mucosae respond to pharmacological agents in a species-different manner.

Aged↗