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Biomedical subjects

H Nakamura

Publications and source records attributed to H Nakamura.

At least 127 records · Page 7Linked to original sources
PubMed2002

Characterization of infiltrating T cells and Th1/Th2-type cytokines in the synovium of patients with osteoarthritis.

OBJECTIVE: It has been suggested that osteoarthritis (OA) is induced by mechanical stress followed by cartilage destruction, and it is generally accepted that there is little involvement of an immune response in OA compared with that in rheumatoid arthritis (RA). We have previously found clonally expanded transcripts of Vbeta chain of the T cell receptor (TCR) in the synovium of patients with OA. To test the hypothesis that an immune response is involved in OA, we determined: (a) whether CD3+, CD4+, and CD8+ T-cells were infiltrating the synovial membrane of patients with OA; (b) the Th1/Th2-type cytokines produced at the protein level in the synovium of patients with OA. METHODS: Immunohistochemical analysis was performed to identify T-cells that infiltrated the synovium of patients with OA using specific antibodies against CD3+, CD4+, and CD8+ T-cell differential antigens, interferon-gamma (IFN-gamma as a marker for Th1 cells, and interleukin-4 (IL-4) as a marker for Th2 cells. RESULTS: CD4+ T-cells were strongly detected in the sublining layer of the synovium of patients with OA compared with the number detected in the same synovial layer of normal subjects. The number of IFN-gamma+ cells was significantly higher than that of IL-4+ cells in the synovium of patients with OA (P< 0.05). CONCLUSION: These observations suggest that Th1 cells predominate in the synovium of patients with OA, which clearly indicates that immune regulation occurs and may play critical roles in inflammation and cartilage destruction in patients with OA.

Aged↗
PubMed2002

Amelanotic malignant melanomas of the oral mucosa.

Oral amelanotic melanomas are rare and the prognosis is poorer than that of pigmented melanomas because of delays in establishing the correct diagnosis and in the initiation of treatment. Amelanotic forms are also thought to be biologically more aggressive than pigmented melanomas. We have seen three cases of oral amelanotic melanomas since 1970, in two of whom the diagnosis was long delayed. Two lesions were not pigmented but one had slight pigmentation. One patient simultaneously had both an amelanotic and a pigmented melanoma in the oral cavity. Lymph node metastases and distant metastases developed in all patients, two of whom eventually died of the disease. Early diagnosis by histological examination together with immunostaining with S100 and HMB-45 are the keys to improve survival for patients with amelanotic melanoma.

Aged↗
PubMed2002

Simultaneous quantification of prostaglandins in human synovial cell-cultured medium using liquid chromatography/tandem mass spectrometry.

A liquid chromatographic-tandem mass spectrometric (LC/MS-MS) method was developed for the simultaneous quantification of prostaglandin (PG) E(2), PGF(2alpha), 6-keto-PGF(lalpha) and thromboxane (TX) B(2). These eicosanoids and their deuterium derivatives, using as internal standards, were extracted by solid-phase extraction and analyzed using LC/MS-MS in the selected reaction-monitoring (SRM) mode. A good linear response over the range of 10 pg to 10 ng for each eicosanoid was demonstrated. The accuracy of added eicosanoids ranged from 94.1 to 106.6% and coefficients of variation ranged from 0.62 to 7.8%. Furthermore, we applied this method for the determination of eicosanoids in the human synovial cell-cultured medium, stimulated by lipopolysaccharide (LPS). LPS produced each eicosanoid and they increased in a time-dependent manner. The production levels after 24 h stimulation were 6-keto-PGF(1alpha) > PGE(2) > TXB(2) >> PGF(2alpha). This simultaneous quantification method is so useful to clarify the function of synovial cells in rheumatoid arthritis (RA).

Calibration↗
PubMed2002

Hepatocyte growth factor in human breast milk acts as a trophic factor.

To evaluate the significance of hepatocyte growth factor (HGF) in milk in the perinatal period, we examined immunoreactive HGF levels and bioactivity in human milk. Human milk samples were obtained from women at various postpartum ages, and the levels of HGF were measured by ELISA. In the cross sectional study, the concentration of milk HGF from term deliveries showed a significant inverse correlation with progress of lactation, whereas in cases of preterm delivery concentrations, levels remained high after a long period of lactation. In the longitudinal analysis, the contents of HGF in colostrum, transitional, and mature milk from preterm deliveries were significantly be higher than those from term deliveries. Although mature milk from term and preterm deliveries contained significantly lower levels of HGF than colostrum, high levels of HGF persisted in mature milk from preterm deliveries. After partial purification, immunoblotting analysis showed the presence of both alpha- and beta-chains of HGF. HGF in milk stimulated proliferation of rat hepatocytes in primary culture, which was inhibited by supplementation with anti-HGF antibody. Thus, a high concentration of bioactive HGF is present in human milk in the postpartum period. Our results suggest that HGF in milk acts as a trophic factor for the gastrointestinal tract in neonates.

Adult↗
PubMed2002

Elevation of serum thioredoxin levels in patients with type 2 diabetes.

To evaluate the clinical significance of thioredoxin in diabetic patients, serum thioredoxin levels measured with a recently established sandwich enzyme-linked immunosorbent assay kit were compared with clinical laboratory data and complications in 174 patients with Type 2 diabetes. Thioredoxin levels were significantly higher in diabetic patients (mean value, 38 ng/ml) than in healthy controls (21 ng/ml) (p < 0.05). Fasting blood sugar and hemoglobin A1c did not correlate with thioredoxin. Plasma non-esterified fatty acids levels were significantly higher in patients with higher thioredoxin levels (>or= 40 ng/ml) than in those with lower thioredoxin levels (< 40 ng/ml) (p < 0.001). There was a significant correlation both between thioredoxin and non-esterified fatty acids in patients with diet/exercise therapy (p < 0.01) and between thioredoxin and fasting immunoreactive insulin in those treated with diet/exercise or oral hypoglycemic agents (p < 0.05). Thioredoxin did not correlate with diabetic complications. In conclusion, serum thioredoxin levels may reflect the status of insulin resistance in Type 2 diabetic patients.

Aged↗
PubMed2002

Increased gastric acid secretion in cholecystokinin-1 receptor-deficient Otsuka Long-Evans Tokushima fatty rats.

BACKGROUND: It is hypothesized that cholecystokinin stimulates acid secretion directly and indirectly by binding to CCK-2 (CCK-B/gastrin) receptors on both parietal and enterochromaffin-like cells. At the same time, however, it inhibits acid responses by stimulating the paracrine secretion of somatostatin from D cells and thereby exerts a tonic inhibition on the parietal cells. To test the validity of this hypothesis, we determined gastric acid secretion in the CCK-1 (CCK-A) receptor-deficient Otsuka Long-Evans Tokushima fatty (OLETF) rats. METHODS: Gastric acid secretion was determined in the acute fistula OLETF and the control Long-Evans Tokushima Otsuka (LETO) rats. Plasma concentrations of gastrin, CCK, somatostatin and histamine were determined by radioimmunoassay. The levels of CCK-2 receptor mRNA in the mucosa of the glandular stomach were determined by Northern blot analysis. RESULTS: Pentagastrin- and CCK-8-stimulated as well as basal acid outputs in OLETF rats were significantly higher than those in LETO rats. CCK-2 receptor antagonist reduced basal acid outputs and completely suppressed CCK-8-stimulated acid secretion in both strains. CCK-8 enhanced the pentagastrin-stimulated gastric acid output in OLETF rats, but not in LETO rats. In LETO rats, CCK-1 receptor antagonist increased CCK-8-stimulated gastric acid secretions to those in OLETF rats. The level of CCK-2 receptor mRNA in the stomach in OLETF rats was 2-fold higher than that in LETO rats. In OLETF rats, plasma concentrations of CCK and histamine were higher, whereas somatostatin concentrations were lower than those in LETO rats, with no change in basal plasma gastrin concentrations. CONCLUSIONS: These results in the CCK-1 receptor-deficient OLETF rats confirmed that CCK stimulates acid secretion by binding to CCK-2 receptors, but at the same time inhibits acid responses by stimulating the paracrine secretion of somatostatin from D cells in the gastric mucosa.

Animals↗
PubMed2002

NOR-1: a nitric oxide releasing agent for calibrating low levels of nitric oxide by the chemiluminescence method.

Nitric oxide (NO) is formed in small amounts in vivo and is rapidly oxidized by interacting with oxygen, making measurement of its level difficult. The chemiluminescence assay is the most widely used method for detecting NO and is extremely sensitive to very small amounts of NO. However, it is difficult to prepare small amounts of NO to be used as a standard for NO analysis. NOR-1, a derivative of NOR-3, is a newly discovered NO donor with rapid NO-releasing activity. We assessed the dynamics of NO release and decomposition using NOR-1. Our results demonstrate that NOR-1 is stable in dimethylsulfoxide (DMSO) and is able to dilute at lower concentration (to picomolar levels) by DMSO without decomposition. NOR-1 released persistently 1.4 more excess of NO with 15 min of incubation. There was a linear relationship between the concentration of NOR-1 and that of NO released from NOR-1 (r=0.997) These findings suggest that NOR-1 is a useful reagent for the calibration of lower NO detection.

Benzoates↗
PubMed2002

Renal cortical retention of contrast medium on delayed CT and nephropathy following transcatheter arterial chemoembolisation in patients with high serum creatinine level.

The aim of this study was to investigate the prevalence of renal cortical retention (RCR) of contrast media seen on delayed CT, and nephropathy following transarterial chemoembolisation (TACE) in high-risk patients. The findings of 18 patients with abnormally high serum creatinine levels who underwent TACE were reviewed. Nephropathy was defined as an increase in serum creatinine level of more than 44 micromol l(-1), or more than 25%, on day 1, 3, 7 or 14. RCR was defined as mild (CT value >50) or severe (CT value >100). RCR was seen in 16 cases (89%) and in seven cases (39%) of post-TACE nephropathy. Patients without severe RCR did not develop nephropathy post-TACE, whereas 50% of those with such retention did (p=0.19). Delayed CT appears to have the potential as an early detector of nephropathy post-TACE in high-risk patients.

Adult↗
PubMed2002

High prevalence of Epstein-Barr virus in gastric remnant carcinoma after Billroth-II reconstruction.

BACKGROUND: Epstein-Barr virus (EBV) has been detected in about 10% of gastric carcinoma cases worldwide, and a high prevalence of EBV involvement in gastric remnant carcinoma has been reported recently. Details of the background remnant stomach of EBV-positive lesions, however, have not been well clarified. METHODS: We screened 17 consecutive gastric remnant carcinoma lesions resected surgically. To detect EBV, we used in situ hybridization (ISH) for EBV-encoded small RNA1 (EBER-1) and we compared the clinicopathologic feature between EBV-positive and -negative gastric remnant carcinoma cases. RESULTS: EBV was detected in 41.8% (7 of 17) of the lesions by EBER-1 ISH. All 7 EBV-positive lesions developed in the anastomotic site had undergone Billroth-II reconstruction excess 20 years previously (mean 26.4 years). Histologically, all EBV-positive lesions were poorly differentiated adenocarcinomas with intense lymphocyte infiltration. In the adjacent mucosa of carcinomas, moderate or marked intestinal metaplasia was found in 85.7% (6 of 7) of EBV-positive lesions and in 40% (4 of 10) of EBV-negative lesions. CONCLUSIONS: EBV infection is strongly associated with gastric remnant carcinoma. Atrophic change of remnant gastritis in Billroth-II anastomoses is considered to be the carcinogenic background for EBV-positive gastric remnant carcinoma.

Adenocarcinoma↗
PubMed2002

[Initial use of the newly developed voice-controlled robot system for a solitary pulmonary arterio-venous malformation].

We herein report an initial experience of thoracoscopic surgery for a solitary arterior-venous malformation (PAVM) with the AESOP 3000 HR voice-controlled robot to hold a thoracoscope. A 52-year-old woman was hospitalized due to a transient loss of consciousness. A brain magnetic resonance image and electroencephalogram (EEG) were normal. A chest computed tomogram indicated a suspicion of PAVM. The definite diagnosis of the PAVM was made by the 3-dimensional computed tomogram and pulmonary angiography. Thoracoscopic operation with the voice-controlled robot (AESOP 3000 HR) was conducted. The operating staffs were able to assemble the AESOP 3000 HR robotic system safely and quickly without difficulty. The robot functioned without problems throughout the procedure. No complications or events related or unrelated to the maneuvers of the robot during the operation were noted. The procedure of the pulmonary resection with the voice-controlled robot was successfully preformed by a single surgeon. The operating time was 110 minutes, and the volume of the intraoperative bleeding was 10 g. The postoperative course was uneventful. The use of the AESOP 3000 HR robot may be more convenient and friendly in thoracoscopic procedure.

Arteriovenous Malformations↗
PubMed2002

[Clinicopathological character and long-term results of thymic epithelial tumor categorized by WHO classification].

We analyzed clinicopathological character and long term results of 50 thymic epithelial tumors with reference to WHO histologic classification. There were 1 type A tumor, 8 type AB tumors, 13 type B1 tumors, 16 type B2 tumors, 10 type B3 tumors, and 2 type C tumors. Clinical stages were progressive in order of classification type A, AB, B1, B2, B3, and C. Type B1 and B2 were highly associated with myasthenia gravis (MG). There were four multiple thimic tumor in patients of advance clinical stage with polygonal epithelial cell tumor. Long term results were poor in order of the classification of type A, AB, B1, B2, B3, and C. In our study, WHO classification finely reflected the clinical character and prognosis of thymic epithelial tumors.

Adult↗
PubMed2002

[Rice-wheat rotational FACE platform. I. System structure and control].

A Free Air CO2 Enrichment (FACE) system for rice and winter wheat rotation was established, elevated CO2 concentration was controlled to 200 mumol.mol-1 above ambient by computer system platform according to ambient CO2 concentration variation, wind direction, wind speed, canopy height and day-night changing. Experiments showed that the main factors affecting control precision are wind speed, crop and soil respiration and thickness of diffuse layer. After parameters adjustment, in daytime the time fraction for control precision achieve 80% is 83%, in night is 68%. The CO2 concentrations distribution in FACE rings are uniformity. The set CO2 is 557 mol.mol-1 in daytime and 608 mol.mol-1 in night. In 2001 rice season the target achievement ratios (TAR) were 1.03 after sunrise and 1.09 after sunset, respectively.

Agriculture↗
PubMed2001

Characterization of low-intensity lesions in the peripheral zone of prostate on pre-biopsy endorectal coil MR imaging.

The aim of this study was to determine which morphological features of low-intensity lesions in the peripheral zone of the prostate are predictable of prostate cancer on pre-biopsy T2-weighted integrated endorectal phased-array MR images. The MR examinations were performed in 69 consecutive patients with elevated level of prostate-specific antigen (>4 ng/ml) and/or a positive digital rectal examination before transperineal 12-site biopsy. Two radiologists evaluated presence of lesions, their morphological features, and possibility of malignancy in divided into four sections of the peripheral zone. Imaging analysis findings were compared with biopsy results. Discriminative features were selected by stepwise logistic regression. Descriptive statistics and receiver operating characteristics (ROC) curves were also calculated. Sixty-eight benign lesions and 23 malignant lesions were found. Wedge shape and diffuse extensions without mass effect were significantly associated with benignity ( P=0.0105 and 0.002, respectively). Lesion size was significantly associated with malignancy ( P=0.0001). For evaluating probability of malignancy for lesions, regression model showed a comparable accuracy with the total impression for the readers in ROC analysis (Az 0.9095 vs 0.9266, respectively). Wedge shape, diffuse extension without mass effect, and size are the morphological features of low-intensity lesions in the peripheral zone on pre-biopsy T2-weighted MR images that give the best prediction of malignancy.

Aged↗
PubMed2001

Circulating thioredoxin suppresses lipopolysaccharide-induced neutrophil chemotaxis.

Thioredoxin (Trx), a redox enzyme with a conserved active site (Cys-32-Gly-Pro-Cys-35), is induced and secreted into circulation in response to inflammation. Studies here demonstrate that elevating Trx levels in circulation either by i.v. injection of recombinant Trx or stimulating Trx release in Trx-transgenic mice dramatically blocks lipopolysaccharide (LPS)-stimulated neutrophil migration in the murine air pouch chemotaxis model. Furthermore, we show that leukocyte recruitment induced by the murine chemokines KC/GROalpha, RANTES (regulated upon activation, normal T cell expressed and secreted), and monocyte chemoattractant protein-1 (MCP-1) is suppressed also in Trx-transgenic mice. Addressing the mechanism responsible for this suppression, we show that circulating Trx blocks (i) the LPS-stimulated in vitro activation of neutrophil p38 mitogen-activated protein kinase, (ii) the normal down-regulation of CD62L on neutrophils migrating into the LPS-stimulated air pouch, and (iii) the in vitro adhesion of LPS-activated neutrophils on endothelial cells. However, as we also show, Trx does not alter the expression of endothelial cell adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, CD62P, and CD62E) within 3 h. Collectively, these findings indicate that elevated levels of circulating Trx interfere with chemotaxis by acting directly on neutrophils. We discuss these findings in the context of recent studies reporting beneficial effects of acutely elevated Trx in ischemic injury and negative effects associated with chronically elevated Trx in HIV disease.

Animals↗
PubMed2001

DNA methylation of the human oxytocin receptor gene promoter regulates tissue-specific gene suppression.

In the human oxytocin receptor (OTR) gene, there is a CpG island from 140 bp upstream to 2338 bp downstream of the transcription start site (TSS). We investigated whether the methylation state of this region affects the transcription of the OTR gene. HepG2 derived from human hepatoblastoma, in which OTR gene transcription was suppressed, was treated with a demethylating agent, 5-azacytidine (Aza-C) for 2 days. Semiquantitative RT-PCR indicated that OTR mRNA was significantly increased by Aza-C treatment in a dose-dependent manner. We estimated the level of methylation within the CpG islands of the OTR gene in peripheral blood leukocytes, nonpregnant uterine myometrium, term uterine myometrium and liver. A 1.5-kb region located 5' upstream of the translation start site was divided into four fragments. Each was amplified by PCR after complete digestion with methylation-sensitive restriction enzyme HpaII. The amount of PCR products was largest in the liver, suggesting that this CpG island in the OTR gene is most highly methylated in liver, where the gene is always inactivated. We compared the effect of in vivo methylation of the CpG island on transcriptional activity of an OTR-reporter plasmid. The reporter gene activity of expression plasmid -2860/+1342-GL3, containing the CpG island, in HepG2 cells was suppressed to 30.6% of the control level after methylation with SssI methylase, while that of -2840/+144-GL3, without the CpG island was suppressed only to 81.4%. The deletion of the segment (MT2) where the level of methylation was most different between liver and uterus (-2860/+1342(del)MT2-GL3) rescued the suppression rate to 68.0%. These results indicate that the methylation of the CpG island in the human OTR gene promoter suppressed its transcription at least in liver and may regulate tissue specific gene expression among organs.

Azacitidine↗
PubMed2001

Expression of bone morphogenetic protein-5 gene during chick heart development: possible roles in valvuloseptal endocardial cushion formation.

The bone morphogenetic protein (BMP) family, comprising multifunctional peptide growth factors, regulates many developmental processes in a variety of tissues. We examined the spatiotemporal expression of BMP5 by in situ hybridization in chick embryonic hearts from stages 5 to 33. The BMP5 gene was first expressed in the endoderm underlying the precardiac mesoderm at stages 5 to 8. Thereafter, BMP5 expression was restricted to the myocardium of the atrioventricular (AV) canal and outflow tract (OT) regions, where the valvuloseptal endocardial cushion tissue is induced. These results suggest that BMP5 may play important roles not only in myocardial differentiation, but also in the formation and maintenance of endocardial cushion tissue.

Animals↗
PubMed2001

Cellular origin of endochondral ossification from grafted periosteum.

Grafted periosteum is known to have potential for heterotopic bone formation by endochondral ossification. Although osteochondrogenic cells have been thought to originate from the osteogenic layer in grafted periosteum, no histological report has yet demonstrated this. The present study was designed to elucidate the origin of chondrogenesis preceding bone formation in grafted periosteum. Periostea harvested from young Japanese white rabbits' tibiae were grafted into suprahyoid muscles and examined radiographically and histologically at postoperative days 1, 7, 9, 14, 21, and 35. Normal periostea and tibial graft site were also examined. Surgical harvesting of the periosteum split and damaged its osteogenic layer but retained the fibrous layer intact. Most of the osteoblasts remained on the tibial bone surface, and only few cells of the osteogenic layer were present in grafted tissue. By the seventh day after grafting, the fibrous layer had thickened. The fibroblastic cells in the fibrous layer had significantly increased in number (P < 0.01) and were positively stained for proliferating cell nuclear antigen. These cells exhibited alkaline phosphatase activity at day 9. The differentiated chondrocytes had formed cartilage at postoperative day 14. Cells in the osteogenic layer appeared necrotic and subsequently disappeared. Following postoperative day 21, cartilage was replaced by trabecular bone. Bone formation was completed by 35 days. An X-ray analysis at this time also revealed new bone formation. These findings indicate that grafted periosteum forms bone by endochondral ossification and that the cells of the fibrous layer play essential roles in chondrogenesis that precedes such bone formation.

Alkaline Phosphatase↗