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N Nagata

Publications and source records attributed to N Nagata.

At least 37 records · Page 2Linked to original sources
PubMed2001

Age-associated increase of 8-hydroxydeoxyguanosine in human colorectal tissue DNA.

To clarify the role of oxidative stress in aging of colorectal tissue, we analyzed the 8-hydroxydeoxyguanosine (8-OH-dG) levels in colorectal biopsy samples from normal tissue of patients with either colorectal cancer (n = 15) or benign colorectal polyps (n = 40). An age-associated increase of 8-OH-dG was observed (p =.002), although the 8-OH-dG levels were not significantly different between the patients with cancer and those with polyps. These results suggest an increased level of 8-OH-dG formation in human colorectal tissue with age.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Brassinazole, an inhibitor of brassinosteroid biosynthesis, inhibits development of secondary xylem in cress plants (Lepidium sativum).

Brassinazole (Brz) is a specific brassinosteroid biosynthesis inhibitor. Cress plants (Lepidium sativum) grown in medium containing Brz exhibited a slight predominance of phloem differentiation at the expense of xylem differentiation and remarkable inhibition of the development of secondary xylem. This result indicates that brassinosteroids function in xylem development in vivo.

Arabidopsis↗
PubMed2001

The chemistry and biological effects of malondialdehyde-acetaldehyde adducts.

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Geoffrey M. Thiele and Simon Worrall. The presentations were (1) The chemistry of malondialdehyde-acetaldehyde (MAA) adducts, by Dean J. Tuma; (2) The formation and clearance of MAA adducts in ethanol-fed rats, by Simon Worrall; (3) Immune responses to MAA adducts may play a role in the development of alcoholic liver disease, by Lynell W. Klassen; (4) Unique biological responses to MAA-modified proteins that may play a role in the development and/or progression of alcoholic liver disease, by Geoffrey M. Thiele; (5) MAA-adducted bovine serum albumin activates protein kinase C and stimulates interleukin-8 release in bovine bronchial epithelial cells, by Todd A. Wyatt; and (6) An enzyme immune assay for serum antiacetaldehyde adduct antibody using low-density lipoprotein-adduct and its significance in alcoholic liver injury and ALDH2 heterozygotes, by Naruhiko Nagata.

Acetaldehyde↗
PubMed2001

Rapid detection of chromosome aneuploidies by prenatal interphase FISH (fluorescence in situ hybridization) and its clinical utility in Japan.

OBJECTIVE: The purpose of this study was to assess the accuracy, informative rate, detection rate, and clinical utility of prenatal interphase fluorescence in situ hybridization (FISH) analysis of amniotic fluid samples from Japanese women. METHODS: Amniotic fluid specimens from 2,639 Japanese women were received for prenatal interphase FISH and chromosome analysis. A questionnaire was designed to evaluate FISH clinical utility by collaboration sites. RESULTS: Based on 2,319 tested samples, the accuracy (100%), informative (94%), and detection (87.6%) rates were all high. The accuracy (100%), informative (90.2%), and detection (90.0%) rates were also remarkable in third-trimester pregnancies. We perceive significant advantages from this test regarding medical management and patient satisfaction. CONCLUSIONS: This novel report shows that in Japan prenatal interphase FISH testing is highly informative and accurate, not only in second-trimester pregnancies but also in third-trimester pregnancies. This test provides advantages to both physicians and patients, provided that its capabilities and limitations are understood.

Adult↗
PubMed2001

Distribution of oxygenated blood flow at three different routes of extracorporeal membrane oxygenation in exteriorized fetal lambs.

OBJECTIVE: The purpose of this study was to determine which extracorporeal membrane oxygenation (ECMO) route best approximates the normal physiologic pattern of oxygenated blood distribution in fetal lambs submerged in warm saline solution. STUDY DESIGN: Six fetal lambs ranging from 113 to 129 days of gestation were delivered by cesarean section and oxygenated with ECMO in a warm saline solution bath. We compared the distribution of oxygenated blood flow during intact placental circulation with 3 routes of ECMO, from the right atrium to the carotid artery (V-A), from the right atrium to umbilical vein (V-UV), and from the right atrium with umbilical artery to umbilical vein [(V + UA)-UV], in exteriorized fetal lambs. Distribution of oxygenated blood flow was determined by nonradioactive colored microspheres. RESULTS: The ECMO blood flow rate through the catheters during V-A, V-UV or (V + UA)-UV ECMO ranged at 150 to 300 ml/min. Among the 3 different routes of ECMO, the oxygenated blood distribution in (V + UA)-UV showed the best correlation with placental-fetal blood flow, particularly in the brain and heart. CONCLUSION: This study indicated that (V + UA)-UV ECMO most closely approximates normal intact placental-fetal blood flow distribution in fetal lambs.

Animals↗
PubMed2001

Expression of P-glycoprotein in human placenta: relation to genetic polymorphism of the multidrug resistance (MDR)-1 gene.

To evaluate whether mutations in the human multidrug resistance (MDR)-1 gene correlate with placental P-glycoprotein (PGP) expression, we sequenced the MDR-1 cDNA and measured PGP expression by Western blotting in 100 placentas obtained from Japanese women. Nine single nucleotide polymorphisms (SNPs) were observed with an allelic frequency of 0.005 to 0.420. Of these SNPs, G2677A (allelic frequency = 0.18) and G2677T (0.39) in exon 21 were associated with an amino acid conversion from Ala to Thr and to Ser, respectively. Sixty-one of 65 samples (93.8%), which had a C3435T allele, also had a mutant G2677(A,T) allele, suggesting an association between the two SNPs. Correlations of mutations with expression levels were observed; individuals having the G2677(A,T) and/or T-129C (p < 0.05) allele had less placental PGP. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based genotyping tests were developed for the detection of these SNPs. The PCR, in which genomic DNAs obtained from healthy subjects (n = 48) are used as samples, was successful. The frequency of mutations in placental cDNA was identical with that in genomic DNA. When genotype results were compared between Caucasians and Japanese, ethnic differences in the frequency of polymorphism in the MDR-1 gene were suspected. Although it remains to be determined whether these SNPs influence the pharmacokinetic and dynamic properties of clinically useful drugs that are substrates of PGP, the polymorphism of the MDR-1 gene presented here may provide useful information in in vivo study of these issues.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

[Follicular bronchiolitis associated with pulmonary tuberculosis--report of a case].

The patient, a 39-year-old man, presented in May 1997 with an untreated persistent cough with excessive sputum of 5 years' duration. He was admitted to hospital because of the severity of the symptoms and the presence of acid-fast bacilli in his sputum. These bacilli were identified as Mycobacterium tuberculosis by the polymerase chain reaction method. After treatment with antituberculous drugs was initiated, his symptoms and the patchy infiltrative shadows on his chest radiographs gradually resolved. However, the patient continued to expectorate a purulent sputum, showed diffuse micronodular shadows on chest radiographs, and had hypoxemia as well as mixed ventilatory and small airway disturbances on pulmonary function tests. We performed a video-assisted thoracoscopic biopsy of the lung, which revealed follicular bronchiolitis.

Adult↗
PubMed2001

[Surgical techniques and results of right ventricular [correction of venericular] outflow tract reconstruction with pedicled autologous tissue].

From 1987 to 2000, 44 patients underwent anatomic repair of anomalies with pulmonary outflow obstruction by using pedicled autologous tissue in reconstructing the pulmonary outflow tract. Twenty-four patients had tetralogy of Fallot with pulmonary atresia (TOF/PA), from 1.7 years to 12.9 years of age (mean 9.0 years). In the group of TOF/PA, slit-widening method was performed in 22, autologous pericardial flap was used in 1, and atrial appendage was used in 4 patients. Eight patients had transposition of the great arteries with ventricular septal defect and pulmonary stenosis (TGA type III), from 9 months to 9.2 years of age (mean 4.5 years). All of the patient with TGA type III under went direct PA-RV anastomosis (natural route non-conduit repair). Three patients had truncus arteriosus, from 1 month to 7.8 years of age (mean 4.5 years). In the group of the truncus, atrial appendage was used in 1 and direct PA-RV anstomosis was made in 2 patients. Six patients had Rastelli's conduit obstruction, from 6.6 years to 20.3 years of age (mean 13.9 years). The conduit was removed and outflow tract was reconstructed with direct PA-RV anastomosis in 5 and using atrial appendage in 1 patients. There was one hospital death (2%) and no late deaths. In 31 patients whose follow-up time exceed 5 years, 7 patients (23%) were found to have pressure gradient more than 40 mmHg at the pulmonary outflow tract. None of the patients with TGA who underwent natural route non-conduit repair developed late stenosis at the pulmonary out flow tract.

Cardiac Surgical Procedures↗
PubMed2001

[Pulmonary Mycobacterium Kansasii infection in the southern area of Fukuoka prefecture].

Cases of pulmonary infection caused by Mycobacterium kansasii (Mk) in our hospital located at the mid-northern area of the Kyushu district, which is in the southern part of Fukuoka prefecture were evaluated. Mk infection is not so rare in other areas of Japan, such as Tokyo and Kinki district, however, there has been no published report on the disease from the Kyusyu district. Therefore, the frequency and the clinical features of our cases of Mk infection were analyzed. During 17 years from 1982 to 1998, there were 14 patients of Mk infection out of 241 nontuberculous mycobacteriosis (NTM). There were 595 patients of culture-positive pulmonary tuberculosis without prior treatment (Tbc). The proportion of Mk/Tbc was 2.4% and that of Mk/NTM was 5.8%. During the period A (from 1982 to 1994) the ratio of Mk/Tbc was 5/462 (1.1%), while on the other side that of Mk/Tbc during the period B (from 1995 to 1998), it was 9/133 (6.8%), which was significantly (P < 0.01) higher compared with that in the period A. Although the patients of Mk infection in our hospital had been rare until 1994, from the results mentioned above, it was considered that the frequency of Mk infection in our hospital has increased to some extent since 1995. One of the characteristics in our cases was that the ratio of female (42.9%) was relatively high. All the female patients were considered to be compromised hosts. The results of the drug resistance tests were consistent with the other reports in our country. By the combination treatment including rifampicin as the major drug, the negative conversion of culture were obtained within 2 months in all our cases.

Adult↗
PubMed2001

Evaluation of insulin secretion of isolated rat islets cultured in extracellular matrix.

Islet isolation involves enzymatic digestion of the interstitial matrix and mechanical disruption of the tissue. It is possible that a fundamental change of islet biology resulting from the loss of critical factors required for islet function or survival will occur. Extracellular matrix (ECM) is one of the most important components of the islet microenvironment. Reconstruction of the cell-matrix relationship seems to be effective for improving the loss of differentiated islet structure and function. The purpose of this study was to characterize and compare the effects of collagen gel mixture or Matrigel on beta-cell function and islet cell survival. After isolation by the collagenase digestion technique, rat islets were divided and cultured with various types of collagen gel mixture. They were assessed for their glucose-stimulated insulin secretion and cell viability. Glucose-induced insulin secretion of islets cultured with collagen type I gel or a mixture of collagen type I and IV was improved after 11 days in culture. In conclusion, a type of gel composed of collagen type I and/or type IV as an islet microenvironment is sufficient to maintain glucose responsiveness and may be useful for islet transplantation.

Animals↗
PubMed2001

Development of a new method to induce angiogenesis at subcutaneous site of streptozotocin-induced diabetic rats for islet transplantation.

The subcutaneous space is a potential site for clinical islet transplantation. Even though there are several advantages, poor blood supply at this site mainly causes failure of islet survival. In this study, angiogenesis was induced in advance at the diabetic rats subcutis for islet transplantation by implanting a polyethylene terephthalate (PET) mesh bag containing gelatin microspheres incorporating basic fibroblast growth factor (bFGF) (MS/bFGF) and a collagen sponge. The bFGF was incorporated into gelatin microspheres for controlled release of bFGF. As controls, a PET mesh bag with or without either collagen sponges or MS/bFGF was implanted at the subcutaneous site of diabetic rats. Macroscopic and microscopic examinations revealed the formation of capillary network in and around the PET mesh bag containing MS/bFGF and collagen sponges 7 days after implantation when compare with other control groups. When tissue hemoglobin level was also measured, a significantly high level of hemoglobin amount was observed compared with that of control groups. When allogeneic islets mixed with 5% agarose were transplanted into the prevascularized rat subcutis, normoglycemia was maintained for more than 40 days, while other control groups were ineffective. This study demonstrated that combination of gelatin microspheres incorporating bFGF and collagen sponges enabled the mesh to induce neovascularization even at the subcutaneous site of streptozotocin-induced diabetic rats, resulting in improved function of islet transplantation.

Animals↗
PubMed2001

Isolation, culture, and characterization of endocrine cells from 6-month-old porcine pancreas.

Porcine endocrine cells were isolated from pancreas of 6-month-old pigs by two-step enzymatic digestion procedures. They were separated by the density gradient (isopycnic) centrifugation method using Histopaque-1077. Isolated cells were cultured and divided into two groups: suspension cells and adhesion cells. Suspension cells maintained their cell numbers on and after 7 days in culture. Approximately 1 x 10(7) cells were obtained from single pancreas of a 6-month-old pig. The cultured suspension cells took up dithizone (DTZ) staining 14 days after isolation in culture and indicated the presence of beta-cells. In in vitro study, the suspension cells were capable of secreting insulin into the culture medium. The suspension cells were tested for insulin and glucagon staining by Western blot analysis. These results indicated the maintenance of endocrine cell function after isolation. However, cultured adhesion cells failed to maintain their function during culture. In in vivo study, the suspension cells were transplanted into diabetes-induced nude mice. Reduction in blood glucose level was obtained after transplantation. Intraperitoneal glucose tolerance test (IPGTT) results showed a normal pattern of blood glucose clearance. After 1 week, the transplanted endocrine cells were detected with anti-insulin antibody by immunostaining and it showed the presence of viable beta-cells under the renal capsule of nude mice. Collectively, our results suggest that isolated and cultured suspension porcine endocrine cells maintained their endocrine function. These endocrine cells can be used as isolated islets for further study, including transplantation experiments.

Animals↗
PubMed2001

Effect of basic fibroblast growth factor on insulin secretion from microencapsulated pancreatic islets: an in vitro study.

Microencapsulation of pancreatic islets represents a potentially effective method to prevent graft rejection in allotransplantation or xenotransplantation without the need of immunosuppression. Adequate insulin secretion and glucose responsiveness of microencapsulated pancreatic islets has been regarded as a prerequisite for successful transplantation. The microencapsulated pancreatic islets were respectively cultured in bFGF+ RPMI-1640 medium (bFGF+) or bFGF- RPMI-1640 medium (bFGF-) for 21 days. The functional activities of microencapsulated pancreatic islets were assessed by measuring basal insulin secretion and stimulated insulin release at different time points. The results revealed that microencapsulated pancreatic islets in the presence of bFGF demonstrated an increase in basal insulin secretion. Furthermore, microencapsulated pancreatic islets in the presence of bFGF demonstrated a marked stimulated insulin release and relative stability of stimulation indices (SI). The results in the perifusion study showed that microencapsulated pancreatic islets in the presence of bFGF maintained good glucose responsiveness over the course of culture period as well. These results indicate that bFGF has a beneficial effect on insulin secretion from microencapsulated pancreatic islets during in vitro culture. New strategies for preserving and improving function of microencapsulated pancreatic islets prior to transplantation may be developed by application of growth factors or other factors.

Animals↗
PubMed2001

A chloroplast protein homologous to the eubacterial topological specificity factor minE plays a role in chloroplast division.

We report the identification of a nucleus-encoded minE gene, designated AtMinE1, of Arabidopsis. The encoded AtMinE1 protein possesses both N- and C-terminal extensions, relative to the eubacterial and algal chloroplast-encoded MinE proteins. The N-terminal extension functioned as a chloroplast-targeting transit peptide, as revealed by a transient expression assay using an N terminus:green fluorescent protein fusion. Histochemical beta-glucuronidase staining of transgenic Arabidopsis lines harboring an AtMinE1 promoter::uidA reporter fusion unveiled specific activation of the promoter in green tissues, especially at the shoot apex, which suggests a requirement for cell division-associated AtMinE1 expression for proplastid division in green tissues. In addition, we generated transgenic plants overexpressing a full-length AtMinE1 cDNA and examined the subcellular structures of those plants. Giant heteromorphic chloroplasts were observed in transgenic plants, with a reduced number per cell, whereas mitochondrial morphology remained similar to that of wild-type plants. Taken together, these observations suggest that MinE is the third conserved component involved in chloroplast division.

Amino Acid Sequence↗
PubMed2001

[Multiple cerebral tuberculomas presenting with paradoxical expansion: a case report].

A 24-year-old male presented with headache. He had been treated with antituberculous drugs for 19 months. MRI revealed 4 intracranial Gd-DTPA enhanced lesions surrounded by massive edema in the right frontal, both occipital and left basal ganglionic regions. Digital subtraction angiography showed no tumor stain. Two procedures for tumor resection were performed for the right frontal and left occipital regions, the latter of which definitively diagnosed by the polymerase chain reaction method. The tumors were well demarcated, showed a rough surface, and were elastically hard. The two residual lesions responded differently to chemotherapy. The lesion in the right occipital region decreased in size, while the other in the left basal ganglionic region continued to grow gradually 26 months after the antituberculous chemotherapy was started. According to previous reports, treatment should be continued for as long as 12-30 months in cases showing paradoxical expansion. In this case, the left basal ganglionic lesion began to decrease in size after 28 months of administration of anti-tuberculous drugs. We report successful treatment of a case of multiple tuberculomas presenting with paradoxical expansion managed by a combination of surgery and continuous chemotherapy.

Adult↗
PubMed2001

Neurovirulence of Sabin 1-derived polioviruses isolated from an immunodeficient patient with prolonged viral excretion.

We have analysed the neurovirulence of Sabin 1-derived isolates which persisted more than nine years in an immunodeficient patient in the U.S.A. Samples were collected from stool specimens at days 11 (St1), 23 (St2), 48 (St3), 126 (St5), and 200 (St7) after the onset of paralysis. Critical nucleotides associated with the reversion of virulence were examined. All the isolates had the substitutions at nucleotide positions 480 (G to A) in the 5'-non-coding region (NCR), 2438 (A to U) in VP3, 2795 (A to G) in VP1, and 6203 (C to U) in 3D. Serially diluted samples were injected intracerebrally to transgenic mice harbouring the human poliovirus receptor gene. Samples St2, 3, 5 and 7 showed typical virulent characters in transgenic mice, whereas the sample ST1 showed intermediate neurovirulence. It seemed that there were two variant viruses providing for a major (M) and a minor (m) populations. After disappearance of the m-variant, samples obtained at the later stages showed neurovirulence almost equivalent to that of the Mahoney strain. Thus, the Sabin 1 strain evolved towards full neuropathogenicity after long-term replication in humans by accumulating mutations. Therefore, OPV-vaccination of immunodeficient persons should be avoided.

Animals↗
PubMed2000

A novel 31-amino-acid-length endothelin, ET-1(1-31), can act as a biologically active peptide for vascular smooth muscle cells.

Human chymase produces a novel endothelin-1 with 31 amino-acid length ¿ET-1(1-31)¿, which is longer than conventional ET-1, ¿ET-1(1-21)¿. The aim of our study was to investigate the role of ET-1(1-31) on porcine coronary vascular smooth muscle cell (VSMC). Although the increase in [Ca(2+)](i) by ET-1(1-31) was 10 times weaker than that of ET-1(1-21), ET-1(1-31) showed equivalent potency in VSMC proliferation, c-fos/c-myc mRNA expression and cell cycle analysis with ET-1(1-21). ET-1(1-31) significantly induced expression of cyclin D1 but not those of cyclin D2 or D3. These effects were specifically inhibited by BQ485, an ET(A) receptor antagonist, although that of ET-1(1-21) was not specific to BQ485, suggesting different receptor specificity from ET-1(1-21). These results indicate that ET-1(1-31) also can involve a VSMC proliferation process such as atherosclerosis, although it has weaker vasoconstricting potency and different receptor subtypes on VSMC from those of ET-1(1-21).

Animals↗