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Biomedical subjects

Y Shimada

Publications and source records attributed to Y Shimada.

At least 55 records · Page 3Linked to original sources
PubMed2003

Genetic susceptibility to thymic lymphomas and K-ras gene mutation in mice after exposure to X-rays and N-ethyl-N-nitrosourea.

PURPOSE: Ras activation is one of the major mechanisms for the development of murine thymic lymphomas by radiation and chemical carcinogens. To gain insight into the relationship between genetic susceptibility and ras gene mutation, the frequency and spectrum of ras gene mutation was examined in thymic lymphomas from susceptible and resistant mice. MATERIALS AND METHODS: K- and N-ras mutations in thymic lymphomas that arose in X-ray-irradiated and N-ethyl-N-nitrosourea (ENU)-treated mice of susceptible C57BL/6, rather resistant C3H and their hybrid B6C3F1 were analysed by polymerase chain reaction-single-strand conformation polymorphism and subsequent DNA sequencing. RESULTS: C57BL/6 exhibited a higher incidence of thymic lymphomas after exposure to X-rays and ENU than C3H, with B6C3F1 being intermediate. K-ras gene mutations occurred frequently in the pathogenesis of ENU-induced thymic lymphomas in susceptible C57BL/6 as opposed to resistant C3H. The ras mutations were more frequent in ENU-induced thymic lymphomas than X-ray-induced thymic lymphomas, and with the latter, there was no clear evidence for strain differences, suggesting that the genetic susceptibility to X-rays was independent of ras activation. The mutations of K-ras in thymic lymphomas from C57BL/6 were predominantly GGT to GAT in codon 12, whereas this mutation type was never found in those from C3H. No strain difference was observed in the nucleotide sequence or expression levels of O(6)-alkylguanine alkyltransferase, indicating that this enzyme did not account for the genetic susceptibility to ras activation. CONCLUSIONS: The results indicate that there is a clear strain and carcinogen dependency of K-ras mutation and that the frequency of ras mutation might determine the genetic susceptibility to ENU-induced lymphomagenesis, whereas pathways independent of ras activation might determine the susceptibility to X-ray-induced lymphomagenesis.

Alkylating Agents↗
PubMed2003

Single-nucleotide polymorphism in the CD14 promoter and periodontal disease expression in a Japanese population.

It has been reported that there is a relationship between a single-nucleotide polymorphism (SNP) in the promoter region of the CD14 gene at position -159 (C-->T) and infectious diseases. The aim of the present study was to test the hypthesis that expression of this SNP correlates with periodontal disease in a Japanese population. The CD14 genotype was determined in 163 subjects with periodontitis and in 104 age- and gender-matched control subjects without periodontitis. The genotype distribution and allele frequency within the periodontitis patients were not significantly different from those of control subjects. There was, however, a significant difference in the genotype distribution between young patients (< 35 yrs) and older patients (>/==" BORDER="0"> 35 yrs). These findings suggest that CD14 -159C/T polymorphism is not related to the development of periodontitis in a Japanese population, but that, within the periodontitis subjects, expression of the SNP may be related to early disease activity.

Adult↗
PubMed2003

[Off-pump coronary artery bypass grafting; its impact on renal function].

PURPOSE: We evaluated the impact of off-pump coronary artery bypass grafting (off-pump CABG: OPCAB) on the perioperative renal function. METHODS: Isolated CABG was performed on 359 patients during the period from January 1999 to September 2002. Nine patients on dialysis were excluded from this study and 350 patients were divided into 2 groups: OPCAB Group (n = 214) and on-pump Group (n = 136). Perioperative serum CRE levels of the 2 groups were compared. RESULTS: The ratio of patients with renal impairment (CRE > 1.5 mg/dl) in the OPCAB Group was 8%, which did not differ statistically from that of the on-pump Group (4%). Patients who had renal impairment postoperatively accounted for 20% of the OPCAB Group, which did not differ from that of the on-pump Group (18%). The postoperative CRE/preoperative CRE ratio was lower in the OPCAB Group (1.28) than that of the on-pump Group (1.44). CONCLUSION: The renal function was preserved in the OPCAB Group compared to the on-pump Group.

Aged↗
PubMed2002

Effects of Choto-san on hemorheological factors and vascular function in stroke-prone spontaneously hypertensive rats.

Choto-san is a formula used for the treatment of headache and vertigo. Recently it has often also been used for hypertension and dementia. One of the mechanisms involved is thought to be the improvement of blood circulation, but the details are still unclear. In this study, the effect of Chotosan was studied on nitric oxide (NO) function, hemorheological factors and endothelial function in stroke-prone spontaneously hypertensive rats (SHR-SP). Rats were given Choto-san in drinking water for eight weeks. Body weight, blood pressure, serum NO2-/NO3-, lipid peroxides, blood viscosity, erythrocyte deformability and endothelium-dependent/-independent relaxation were measured. The results indicated that Choto-san caused a decrease in blood pressure and an increase in erythrocyte deformability and NO function. Blood viscosity was not changed. Furthermore, endothelium-dependent relaxation by acetylcholine was significantly increased as compared to control. In this study, it was supposed that Choto-san had a protective effect on the endothelium. SHR-SP is a useful model for human brain stroke, and Choto-san showed a protective effect against cerebral vascular injury in the susceptible rat.

Acetylcholine↗
PubMed2002

Effect of Seihai-to, a Kampo medicine, in relapsing aspiration pneumonia--an open-label pilot study.

Two published case reports described palliation of disease after Seihai-to therapy for refractory aspiration pneumonia caused by recurrent laryngeal nerve paralysis and cerebrovascular disease. We undertook an open-label trial in patients with relapsing aspiration pneumonia. Fifteen patients with relapsing aspiration pneumonia were randomly divided into conventional therapy group (n = 8) or Seihai-to group (n = 7). In Seihai-to group, patients were treated with Seihai-to in addition to conventional therapy (Western medicines). Frequency of feverish days and antibiotics-use, CRP value and chest CT or X-ray findings were compared between the two groups during the study period of 16 weeks. In the Seihai-to group, the latency of swallowing reflex was measured in 6 patients before and after administration of Seihai-to. The mean values of fever index, CRP value and antibiotics-use in the Seihai-to group were decreased significantly, compared with those of the conventional therapy group. However, the latency of the swallowing reflex after 4 weeks of treatment was not significantly changed (p = 0.249), compared with the latency before administration of Seihai-to. No adverse reaction was observed in either group. Seihai-to was effective in reducing relapse of aspiration pneumonia in this small group. Seihai-to might not improve the swallowing reflex, but might instead improve a defense mechanism or excessive inflammation caused by pneumonia in the lower airway. Further evaluation of Seihai-to therapy for patients with aspiration pneumonia in a larger population is warranted.

Aged↗
PubMed2002

Incidence and clinical features of liver injury related to Kampo (Japanese herbal) medicine in 2,496 cases between 1979 and 1999: problems of the lymphocyte transformation test as a diagnostic method.

We retrospectively examined the summaries of all admission records of patients from 1979 to 1999 in our department, and selected for further study all liver injuries suspected of being related to Kampo medicines. Among 2,496 summaries, 30 summaries described liver disorders suspected of being related to Kampo medicines. Whether there was a causal relationship between the use of Kampo medication and the occurrence of liver injury was assessed according to the criteria described by Haller and Benowitz (2000), independently of the results of the lymphocyte transformation test (LTT). Among 30 events, we concluded that 9 were definitely unrelated, and 6 were probably unrelated to the use of Kampo medicines. Nine events (0.36% of 2,496 patient admissions and 0.06% of 14,616 outpatients) were considered possibly related, and only 6 events (0.24% of 2,496 patient admissions and 0.04% of 14,616 outpatients) were judged to be definitely or probably related to Kampo medicines. Low-grade eosinophilia was observed in a few patients of these "related" groups, and no fever or rash was observed in these "related" groups. Other clinical features, including type of liver injury, duration of Kampo medicine-use, recovery period and laboratory data, were not different from liver injuries associated with western drugs. Most patients in the definitely "unrelated" group were positive in the LTT for the suspect Kampo medicine, suggesting that the LTT may be unreliable for the diagnosis of Kampo-medicine-induced liver injury. From 1979 to 1999, our use of Kampo medicines to treat patients resulted in a low rate of liver injury and no fatalities.

Adolescent↗
PubMed2002

Inhibitory effects of Choto-san (Diao-teng-san), and hooks and stems of Uncaria sinensis on free radical-induced lysis of rat red blood cells.

The present study is designed to test our hypothesis that the ingestion of Uncaria sinensis (US), the main medicinal plant of Choto-san (Diao-teng-san, CS), would protect red blood cell (RBC) membrane from free radical-induced oxidation if polyphenolics in US could be absorbed and circulated in blood. When incubated with RBC suspension, Choto-san extract (CSE) and Uncaria sinensis extract (USE) exhibited strong protection for RBC membrane against hemolysis induced by 2,2-azo-bis (2-amidinopropane) dihydrochloride (AAPH), an azo free-radical initiator. The inhibitory effect was dose-dependent at concentrations of 50 to 1000 microg/mL. Ingestion of 200 mg of USE was associated with a significant decrease in susceptibility of RBC to hemolysis in rats. Furthermore, caffeic acid, an antioxidative hydroxycinnamic acid, was identified in rat plasma after administration of URE.

Amidines↗
PubMed2002

A comparative study between excess-dose users and regular-dose users of rhubarb contained in Kampo medicines.

With prolonged use of rhubarb-containing Kampo medicines, some patients come to ask for high-dose rhubarb because of deteriorated reactivity to rhubarb. We divided patients into two groups in terms of rhubarb-dose, and compared clinical backgrounds between regular-dose group and excess-dose group. Patients who were treated with rhubarb-containing Kampo extracts (manufactured prescriptions) or Kampo formulae (decoctions) for more than 12 months were enrolled. These two groups were compared for age, sex, shape of stool, abdominal symptoms, existence of hemorrhoids, Kampo diagnosis of abdomen, past stimulant laxative use, duration of stimulant laxative use before the first administration of rhubarb, duration of rhubarb use in our hospital, and initial existence of stimulant pain caused by taking stimulant laxatives for the first time. No significant difference was shown between the two groups in terms of age, duration of stimulant laxative-use before the first prescription of rhubarb, shape of stool, abdominal symptoms, existence of hemorrhoids, or duration of rhubarb-use. However, most patients in the regular-dose group had initial stimulant pain of the abdomen upon taking stimulant laxatives for the first time, but most patients in the excess-dose group did not (p < 0.001). All patients except one in the regular dose group had the sign of "umbilical region tenderness on pressure", but half of the excess-dose group did not have it (p = 0.041). Based on these findings, the absence of "initial stimulant pain" and the absence of "umbilical region tenderness on pressure" may predict increasing or excess use of rhubarb, and long-term use of rhubarb should be discouraged more strongly in the patients without these signs.

Cathartics↗
PubMed2002

Reduction of plasma triglyceride level and enhancement of plasma albumin concentration by Oren-gedoku-to administration.

Oren-gedoku-to (Huanglian-Jie-Du-Tang, OGT) has been used for the treatment of cerebrovascular disease, hypertension, gastritis and liver disease in Japan. The present study was to test whether ingestion of OGT extract (TJ-15) would affect the metabolism of fatty acids and the usual antioxidant molecule (such as albumin, uric acid and bilirubin) levels in human plasma. After the administration of TJ-15, plasma total cholesterol and the triglyceride level significantly decreased, and lipoprotein lipase mass increased. Significant enhancement of plasma albumin level and reduction of the total plasma protein level resulted in an increment of the albumin/globulin ratio. Plasma fibrinogen, an independent risk factor for cerebrovascular disease, declined considerably, but the reduction was not statistically significant. The findings of this study suggest that ingestion of TJ-15 improves the microcirculation through lipid and protein metabolisms, and is useful for the treatment of cerebral vascular attack in human.

Chromatography, High Pressure Liquid↗
PubMed2002

Experimental Helicobacter pylori gastric infection in miniature pigs.

An experimental Helicobacter pylori infection in miniature pigs was developed and investigated. Eighteen miniature pigs were inoculated with an H. pylori strain that has high virulence in mice at c. 5 x 10(10) cfu. H. pylori infection in miniature pigs was achieved by the administration of agar 1% in brucella broth with fetal bovine serum 10% just before inoculation. The bacterial colonisation and distribution were analysed by mapping of viable cell counts in the stomach in pigs of three different ages. The mapping assay was achieved on post-infection day 3 for the 5-day-old and 2-week-old pigs, and between days 41 and 43 for 3-month-old pigs. The highest cell counts were observed in 5-day-old pigs, which averaged 4.9 x 10(6) cfu/g of mucosa (n = 4). The bacteria were colonised mainly in the cardiac and fundus gland region in the 5-day-old and 2-week-old pigs, whereas the colonisation sites did not depend on the region in the 3-month-old pigs. Biopsy assay of the antral mucosa of a 3-month-old pig after H. pylori infection showed that this infection persisted for >22 months. Serum antibody against H. pylori was detected in the infected pigs but not in the uninfected animal. Immunostaining demonstrated the presence of bacteria on the epithelial surface of the infected pigs. A microscopic finding common to all the infected pigs, focal gastritis with infiltration of lymphocytes detected on the lesser curvature of the stomach, resembled the microscopic appearance in H. pylori-infected human patients. These results suggest that miniature pigs might be a suitable model for studying H. pylori infection.

Age Factors↗
PubMed2002

Diagnosis of group A coxsackieviral infection using polymerase chain reaction.

AIMS: To examine the relation between enteroviral infection, especially group A coxsackieviral infection, and acute febrile illness over two summers using tissue culture and polymerase chain reaction (PCR). METHODS: Throat swabs were collected from 246 children from June to August 1997 and 1998. RESULTS: Enteroviruses were isolated from 33/246 samples and 35 other viruses were isolated. Enteroviral genomes were detected in 54/178 samples from which no virus was isolated. Of 41 enteroviral genotypes identified by sequence analysis of PCR products, 38 were group A coxsackieviruses, which are usually difficult to isolate using tissue culture. CONCLUSION: Results indicate that viral detection and identification based on PCR is useful in the diagnosis of group A coxsackieviral infection.

Acute Disease↗
PubMed2002

Ascending aortic cannulation via left thoracotomy for distal aortic arch aneurysm operation.

We have cannulated the ascending aorta for cardiopulmonary bypass via left thoracotomy in order to avoid conventional retrograde perfusion from the femoral arteries, which is associated with an increased risk of cerebral embolism. We use silk sutures to retract the anterior margin of the opened pericardium from the chest wall, which provides good exposure and easy control of the ascending aorta. Between July 1997 and November 2000, cannulation proved easy to do and reliable in 24 serial patients.

Adult↗
PubMed2001

Human gastrinoma cells express calcium-sensing receptor.

The intravenous calcium injection test has been reported to be useful for the diagnosis of gastrinoma. However, the mechanism underlying calcium-evoked gastrin release is not fully understood. We investigated the mechanism of calcium-stimulated gastrin release from gastrinoma cells in vitro with a particular focus on the calcium-sensing receptor (CaR). Human gastrinoma cells were taken from mechanically minced gastrinoma tissues obtained at surgery. In the perifusion system, high [Ca2+]o induced gastrin release from gastrinoma cells. As [Ca2+]o increased, [Ca2+]i rapidly increased, as monitored by fluorometry. The response was not inhibited by nifedipine, a blocker of the voltage-dependent calcium channel. Reverse transcriptase-polymerase chain reaction and subsequent Southern blot hybridization revealed the presence of the CaR gene in human gastrinoma tissues. Moreover, the expression of CaR in gastrinoma tissues was confirmed by immunohistochemistry. Our results demonstrated that CaR was expressed in human gastrinoma cells and could be involved in the mechanism of calcium-evoked gastrin release.

Blotting, Southern↗
PubMed2001

Ligands for peroxisome proliferator-activated receptor gamma inhibit growth of pancreatic cancers both in vitro and in vivo.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed largely in adipose tissues and plays an important role in adipocyte differentiation. Several studies have recently shown that ligands of PPARgamma could lead to growth inhibition in some malignancies. In our study, we focused on pancreatic cancers, because the prognosis of advanced pancreatic cancer has not significantly improved due to its resistance to various chemotherapeutic regimens, so that a novel strategy should be required. We show here that PPARgamma is expressed in 5 pancreatic cancer cell lines detected in both mRNA and protein level as well as in human primary and metastatic pancreatic carcinomas examined by immunohistochemical studies. A specific ligand of PPARgamma, troglitazone, led to G1 accumulation with the increase in p27(Kip1), but not p21(Waf1/Cip1) and inhibited cellular proliferation in a pancreatic cancer cell line, Panc-1. The overexpression of PPARgamma in a pancreatic cancer cell line, KMP-3, caused lipid accumulation, which suggested cell growth in some cancers might be inhibited, at least in part, through terminal differentiation in the adipogenic lineage. In addition, implanted Panc-1 tumors in nude mice showed significant inhibition of tumor growth, when treated with pioglitazone, another specific ligand of PPARgamma. Our results suggest that ligands of PPARgamma may be a novel therapeutic agent for the treatment of pancreatic carcinomas.

Adipocytes↗
PubMed2001

Telomerase activity of the Lugol-stained and -unstained squamous epithelia in the process of oesophageal carcinogenesis.

Up-regulation of telomerase has been reported in many cancers. Our aim was to characterize telomerase activity in various states of the oesophagus to facilitate better understanding of carcinogenesis of oesophageal squamous cell carcinoma. During endoscopic examinations, we obtained 45 Lugol-stained normal epithelia, 31 Lugol-unstained epithelia (14 oesophagitis, 7 mild dysplasia, 5 severe dysplasia and 5 intramucosal cancer) and 9 advanced cancer. Telomerase activity was semi-quantified by a telomeric repeat amplification protocol using enzyme-linked immunosorbent assay, and expression of human telomerase reverse transcriptase mRNA was examined by in situ hybridization. In the Lugol-stained normal epithelia, telomerase activity increased in proportion to the increase of severity of the accompanying lesions, with a rank order of advanced cancer, intramucosal cancer, mild dysplasia and oesophagitis. In the Lugol-unstained lesions and advanced cancer, telomerase activity was highest in advanced cancer. Up-regulation of telomerase in normal squamous epithelium may be a marker of progression of oesophageal squamous cell carcinoma.

Carcinoma, Squamous Cell↗
PubMed2001

Identification of cIAP1 as a candidate target gene within an amplicon at 11q22 in esophageal squamous cell carcinomas.

Amplification of chromosomal DNA is thought to be one of the mechanisms that activate cancer-related genes in tumors. In a recent study, we identified high copy-number amplification at 11q21-q23 in cell lines derived from esophageal squamous cell carcinomas (ESCs) using comparative genomic hybridization. Because 11q21-q23 amplification has been reported in tumors of various other types as well, gene(s) associated with tumor progression may lie within this chromosomal region. To identify the most likely target(s) for amplification at 11q21-q23, we determined the extent of the amplicon by fluorescence in situ hybridization and then analyzed ESC cell lines for expression levels of 11 known genes and one uncharacterized transcript present within the 1.8-Mb commonly amplified region. Only cIAP1, a member of the IAP (antiapoptotic) gene family, was consistently overexpressed in cell lines that showed amplification. Additionally, the cIAP1 protein was overexpressed in the primary tumors from which those cell lines had been established. The ESC cell lines with cIAP1 amplification were resistant to apoptosis induced by chemotherapeutic reagents. An increase in cIAP1 copy number was also detected in 4 of 42 (9.5%) primary ESC tumors that were not related to the cell lines examined. Because inhibition of apoptosis seems to be an important feature of carcinogenesis, cIAP1 is likely to be a target for 11q21-23 amplification and may be involved in the progression of ESC, as well as other malignancies.

Apoptosis↗
PubMed2001

Reduced sensitivity to and ras mutation spectrum of N-ethyl-N-nitrosourea-induced thymic lymphomas in adult C.B-17 scid mice.

Scid mice are defective in the ability to repair DNA double strand breaks and, as a consequence, their cells are radiosensitive. Further, they have been shown to be prone to develop thymic lymphomas (TLs) after small doses of ionizing radiation. Little is known, however, on the role of scid mutation in chemical carcinogenesis. To determine if scid mutation increased predisposition to chemical carcinogenesis, we examined both the susceptibility of scid mice to N-ethyl-N-nitrosourea (ENU)-induced lymphomagenesis and the involvement of ras gene activation. Adult female mice at 8 weeks of age were given ENU in their drinking water at 400 ppm for 2-10 weeks. Contrary to expectations, we observed a two to three-fold reduction in TL development in the scid mice. The highest incidence was achieved by ENU treatment for 8 weeks for scid and wild-type C.B-17 mice, of 42 and 85%, respectively (P<0.05). We investigated whether this was attributable to the usage of the ras mutation pathway. There was, however, no significant difference in the frequency and spectrum of K-ras mutation between the scid and wild-type C.B-17 mice. Most of the K-ras mutations were either GGT to GAT transition in codon 12 (11/23: 48%) or CAA to CCA transversion in codon 61 (8/23: 35%) that was independent of scid background. The incidence of N-ras mutation was very low. These results indicate that scid mice are less susceptible to ENU-induced lymphomagenesis and ras gene mutation frequently occurs in both scid and wild-type C.B-17 mice.

Animals↗