Biomedical subjects

N Oda

Publications and source records attributed to N Oda.

At least 73 records · Page 4Linked to original sources

PubMed1998

Effect of theophylline withdrawal on airway inflammation in asthma.

Theophylline has been used as a bronchodilator in acute and chronic asthma management, although there is accumulating evidence that it may have anti-inflammatory effects. We have investigated the effect of theophylline withdrawal for 6 weeks in asthmatic subjects whose peak expiratory flow (PEF) readings were more than 80% of the predicted value and its variability was less than 20% (Green Zone) by treatment with both a moderate dose of inhaled corticosteroids (BDP), 400-800 microg/day) and low dose theophylline (400 mg/day) for more than 3 months. In 38 asthmatic subjects, changes in clinical symptoms, respiratory function and airway inflammation detected with hypertonic saline induced sputum, and airway reactivity to histamine were investigated. One half of the patients were randomly withdrawn from theophylline, while the other half continued to take the same dose of theophylline for a period of 6 weeks. Mean steady state plasma theophylline concentrations when receiving treatment with theophylline were 8.08 microg/mL in the theophylline withdrawal group and 7.64 microg/mL in the control theophylline group, respectively. Although a significant increase in asthma symptoms emerged in the theophylline group, there were no significant changes in the theophylline administration group. In the theophylline withdrawal group, there were small but significant falls in PEF in the morning, FEV1 and V50 at the end of the study period. Analysis of induced sputum showed that there was also a significant increase in the percentage of total and activated (EG2+) eosinophils only in those patients who withdrew from theophylline. These results indicate that chronic treatment with low dose theophylline exerts an anti-inflammatory effect and that the additional use of theophylline with inhaled corticosteroids provides an effective treatment for moderate asthma. Taken together, we conclude that theophylline has long-term beneficial effects on the chronic asthma management.

Administration, Oral↗

PubMed1997

Recombinant human TSH receptor expressed in E. coli.

We expressed the extracellular domain (20-408 aa, (T) of human TSH receptor (TSHR) in E. coli to detect TSHR autoantibodies (TRAb) and, moreover, we expressed the two portions (20-218 aa (5') and 217-408 aa (3')) of the extracellular domain thought to distinguish thyroid stimulating antibodies (TSAb) from blocking antibodies (TSBAb), using pGEX.3X as the expression vector. Using Western blotting analysis of the sera from patients with autoimmune thyroid disease, sera from Graves' patients and patients with idiopathic myxedema who had TSBAb reacted with the fusion protein (T), but none of the control sera reacted with it. We further evaluated whether or not the positive sear for T recognized fusion proteins (5') or (3'). The sera from Graves' patients reacted with both fusion proteins (5') and (3'). The sera from patients with idiopathic myxedema did not react with either of fusion proteins (5') or (3'). These findings suggest that these recombinant TSHR proteins could be used as antigens to detect TRAb, and differentiate TSABb from patients with idiopathic myxedema.

Antibodies, Blocking↗

PubMed1997

Genetic variation in the hepatocyte nuclear factor-1 alpha gene in Danish Caucasians with late-onset NIDDM.

Non-insulin-dependent diabetes mellitus (NIDDM) is a phenotypically and genetically heterogeneous disorder. A recent random genome mapping study has localized a locus termed NIDDM2 that maps to the region of chromosome 12 that includes MODY3, one of the three genes responsible for maturity-onset diabetes of the young, a monogenic form of NIDDM characterized by early age of onset and autosomal dominant inheritance. These findings suggest that NIDDM2 and MODY3 may represent different alleles of the same gene. MODY3 has recently been shown to be the gene encoding the transcription factor hepatocyte nuclear factor-1 alpha (HNF-1 alpha) thereby allowing us to determine whether mutations in the HNF-1 alpha gene are present in subjects with late-onset NIDDM. We screened 84 white NIDDM patients of Danish ancestry and found four nucleotide substitutions that changed the sequence of HNF-1 alpha, Ile27-->Leu, Ala98-->Val, Ser487-->Asn and Arg583-->Gln, five nucleotide substitutions that were silent and did not change the amino acid, Leu17, Gly288, Leu459 and Thr515, and five substitutions in the intron regions. The frequencies of the codon 27, 98 and 487 amino acid variants were similar in 245 unrelated NIDDM patients and 242 age-matched control subjects. The Arg583-->Gln mutation was found in 2 of 245 NIDDM patients and in none of the control subjects. Thus, genetic variation in the HNF-1 alpha gene is not a common factor contributing to NIDDM susceptibility in white subjects of Danish ancestry.

Age of Onset↗

PubMed1997

Alteration of platelet aggregation in patients with thyroid disorders.

To determine whether Graves' disease or primary hypothyroidism influence platelet function, we evaluated platelet aggregation in the platelet-rich plasma (PRP) from such patients. Platelet aggregation induced by adenosine diphosphate (ADP) in blood obtained from patients with untreated Graves' disease was significantly lower than normal, whereas that in patients with untreated primary hypothyroidism was relatively increased. The magnitude of platelet aggregation induced by collagen in both groups of patients resembled that induced by ADP. However, significant differences were evident between the two diseases (P < .05). In addition, we observed a significant inverse correlation between the extent of platelet aggregation and plasma levels of thyroid hormones (triiodothyronine [T3], thyroxine [T4], and free T3). Platelet aggregation returned to normal when the euthyroid condition was obtained in the patients following administration of antithyroid drugs or thyroid hormone. The findings are consistent with the possibility that thyroid hormones influence platelet aggregation partly via inhibition of myosin light-chain kinase (MLCK).

Adenosine Diphosphate↗

PubMed1997

Evaluation of an automatic-mode image processing method in chest computed radiography.

RATIONALE AND OBJECTIVES: The automatic image processing mode of the storage phosphor computed radiography system was evaluated. MATERIALS AND METHODS: A dedicated chest unit designed for erect view was used to examine a chest phantom. Lucite plates 1, 2, and 3 cm thick that conformed to the shape of the lung were attached to the phantom, and images were obtained in automatic and manual image processing modes. The changes in the optical density of the lung, rib, and heart and the changes in contrast were measured. The degree of diffuse opacity due to the plates and the visibility of superimposed simulated nodular and honeycomb opacities were evaluated. RESULTS: The decrease in optical density and contrast caused by increasing thickness of the Lucite plates was less pronounced in the automatic mode compared with the manual mode. When plates were placed only on the right lung, the optical density and the contrast on the contralateral side either increased or remained unchanged with the automatic mode. The degree of diffuse opacity was rated higher in the manual mode, and the visibility of superimposed simulated opacities was considered relatively constant in the automatic mode. CONCLUSION: The automatic image reading mode used in the computed radiography chest system may mask the detection of abnormalities such as diffuse homogeneous lung opacity.

Evaluation Studies as Topic↗

PubMed1997

Identification of nine novel mutations in the hepatocyte nuclear factor 1 alpha gene associated with maturity-onset diabetes of the young (MODY3).

Maturity-onset diabetes of the young (MODY) is a genetically heterogeneous subtype of non-insulin-dependent diabetes mellitus (NIDDM) characterised by early onset, autosomal dominant inheritance and a primary defect in insulin secretion. Recent studies have shown that mutations in the two functionally related transcription factors, hepatocyte nuclear factor 4 alpha (HNF-4alpha) and hepatocyte nuclear factor 1 alpha (HNF-1alpha) are associated with the MODY1 and MODY3 forms of diabetes respectively, whereas mutations in the enzyme glucokinase are the cause of the MODY2 form. We have examined 10 unrelated Caucasian families in which MODY/NIDDM co-segregated with markers for MODY3 for mutations in the HNF-1alpha gene (TCF1). Ten different mutations were observed in these families, all of which co-segregated with diabetes. There were no obvious relationships between the nature of the mutations observed (i.e. frameshift, nonsense, or missense) or their location in the gene with clinical features of diabetes (age at onset, severity) in these families. The mechanisms by which mutations in the HNF-1alpha gene cause diabetes mellitus are unclear but might include abnormal pancreatic islet development during foetal life thereby limiting their later function, as well as impaired transcriptional regulation of genes that play a key role in normal pancreatic beta cell function.

DNA-Binding Proteins↗

PubMed1997

Pharmacological profile of TH-142177, a novel orally active AT1-receptor antagonist.

The pharmacological properties of TH-142177 (N-n-butyl-N-[2'-(1-H-tetrazole-5-yl) biphenyl-4-yl]-methyl-(N-carboxymethyl-benzylamino)-acetamide), a novel antagonist of the angiotensin II (AII) AT1 receptor, were studied in vitro and in vivo, and compared to those of losartan. In the rat isolated aorta, TH-142177 produced parallel shifts to the right of the concentration-response curves for AII-induced contractions without affecting the maximal response (pA2 = 9.07). The inhibitory potency of TH-142177 in the aorta was about three times greater than that of losartan. TH-142177 completely inhibited the specific binding of [125I]AII to AT1 receptor in rat aortic membranes (Ki = 1.6 x 10(-8) M), whereas specific [125I]AII binding to AT2 receptor in bovine cerebellum and human myocardium was not affected by concentrations of TH-142177 up to 10(-5) M. Losartan also inhibited the [125I]AII binding to rat aortic membranes (Ki = 2.2 x 10(-8) M). Following the intravenous administration to anesthetized normotensive rats, TH-142177 dose-dependently inhibited the increase in systolic blood pressure induced by an intravenous bolus injection of AII that was 1.5 times less potent than losartan. Furthermore, the oral administration of TH-142177 to conscious renal hypertensive rats exerted a dose-dependent reduction of systolic blood pressure without significantly effecting the heart rate. TH-142177 was at least three times more potent than losartan. These results demonstrate that TH-142177 is a potent and selective antagonist of AT1 receptors and by oral administration has a long-lasting antihypertensive activity.

Angiotensin II↗

PubMed1997

A presenilin-1 mutation in a Japanese family with Alzheimer's disease and distinctive abnormalities on cranial MRI.

Some patients with familial Alzheimer's disease (FAD) have mutations in the presenilin-1 (PS-1) gene on chromosome 14. We report a Japanese family with AD and an Ala285Val substitution in exon 8 of the PS-1 gene. FAD in this family was characterized by relatively late onset (mean age, 50 years) and absence of myoclonus, seizures, or paratonia. Levels of tau were markedly elevated in CSF whereas CSF levels of amyloid beta protein were normal. MRI of the cranium showed marked linear signal abnormalities within white matter in the parieto-occipital lobes, consistent with cortical amyloid angiopathy of the type encountered in patients with the PS-1 gene mutation.

Alzheimer Disease↗

PubMed1997

Glutathione-independent formaldehyde dehydrogenase from Pseudomons putida: survey of functional groups with special regard for cysteine residues.

The role of cysteine residues for structure and function of formaldehyde dehydrogenase from Pseudomonas putida was analysed by amino acid sequence comparison, homology-based structure modeling, site-directed mutagenesis, and chemical modification. Five out of seven cysteine residues found in the enzyme were concluded to coordinate with an active site zinc (Cys-46) and structural zinc atoms (Cys-97, -100, -103, and -111) from the sequence comparison with other Zn-containing medium-chain alcohol dehydrogenase homologues. The three-dimensional structure model based on the known structure of the horse liver E-type alcohol dehydrogenase (ADH) indicated that Cys-257 is located very far from the active site Zn and NAD+ binding region, suggesting that Cys-257 does not participate in the enzyme reaction. The structure also suggested that Cys-166 does not coordinate to active site Zn, but Asp-169 functions as a Zn-ligand, instead.

Aldehyde Oxidoreductases↗

PubMed1997

Mutations in the hepatocyte nuclear factor-1alpha gene in MODY and early-onset NIDDM: evidence for a mutational hotspot in exon 4.

We have recently shown that mutations in the gene encoding the transcription factor hepatocyte nuclear factor (HNF)-1alpha are the cause of one form of maturity-onset diabetes of the young (MODY3). Here, we report the exon-intron organization and partial sequence of the human HNF-1alpha gene. In addition, we have screened the ten exons and flanking introns of this gene for mutations in a group of 25 unrelated white subjects from Germany who presented with NIDDM before 35 years of age and had a first-degree relative with NIDDM. Mutations were identified in nine of these individuals, suggesting that mutations in the HNF-1alpha gene are a common cause of diabetes in German subjects with early-onset NIDDM and a family history of diabetes. Thus, screening for mutations in this gene may be indicated in subjects with early-onset NIDDM. Interestingly, three of the nine mutations occurred at the same site in exon 4 with insertion of a C in a polyC tract, centered around codon 290 (designated Pro291fsinsC), thereby resulting in a frameshift during translation and premature termination. Analyses of linked DNA polymorphisms in the HNF-1alpha gene indicated that the Pro291fsinsC mutation was present on a different haplotype in each subject, implying that the polyC tract represents a mutational hot spot. We have also identified the mutation in the HNF-1alpha gene in the Jutland pedigree, one of the original MODY pedigrees reported in the literature, as being a T-->G substitution in codon 241, resulting in the replacement of a conserved Cys by Gly (C241G). The information on the sequence of the HNF-1alpha gene and its promoter region will facilitate the search for mutations in other subjects and studies of the role of the gene in determining normal beta-cell functions.

Adolescent↗

PubMed1997

Mutations in the hepatocyte nuclear factor-1alpha/MODY3 gene in Japanese subjects with early- and late-onset NIDDM.

Recent studies have shown that mutations in the hepatocyte nuclear factor (HNF)-1alpha gene are the cause of maturity-onset diabetes of the young type 3 (MODY3). We have screened 193 unrelated Japanese subjects with NIDDM for mutations in this gene: 83 with early-onset NIDDM (diagnosis at <30 years of age) and 110 with late-onset NIDDM (diagnosis > or = 30 years of age). All of the members of the latter group also had at least one sibling with NIDDM. The 10 exons, flanking introns, and promoter region were amplified using polymerase chain reaction and were sequenced directly. Mutations were found in 7 of the 83 (8%) unrelated subjects with early-onset NIDDM. The mutations were each different and included four missense mutations (L12H, R131Q, K205Q, and R263C) and three frameshift mutations (P379fsdelCT, T392fsdelA, and L584S585fsinsTC). One of the 110 subjects with late-onset NIDDM was heterozygous for the missense mutation G191D. This subject, who was diagnosed with NIDDM at 64 years of age, also had a brother with NIDDM (age at diagnosis, 54 years) who carried the same mutation, suggesting that this mutation contributed to the development of NIDDM in these two siblings. None of these mutations were present in 50 unrelated subjects with normal glucose tolerance (100 normal chromosomes). Mutations in the HNF-1alpha gene occur in Japanese subjects with NIDDM and appear to be an important cause of early-onset NIDDM in this population. In addition, they are present in about 1% of subjects with late-onset NIDDM.

Age Factors↗

PubMed1997

Organization and partial sequence of the hepatocyte nuclear factor-4 alpha/MODY1 gene and identification of a missense mutation, R127W, in a Japanese family with MODY.

Hepatocyte nuclear factor-4 alpha (HNF-4 alpha) is a member of the nuclear receptor superfamily, a class of ligand-activated transcription factors. A nonsense mutation in the gene encoding this transcription factor was recently found in a white family with one form of maturity-onset diabetes of the young, MODY1. Here, we report the exon-intron organization and partial sequence of the human HNF-4 alpha gene. In addition, we have screened the 12 exons, flanking introns and minimal promoter region for mutations in a group of 57 unrelated Japanese subjects with early-onset NIDDM/MODY of unknown cause. Eight nucleotide substitutions were noted, of which one resulted in the mutation of a conserved arginine residue, Arg127 (CGG)-->Trp (TGG) (designated R127W), located in the T-box, a region of the protein that may play a role in HNF-4 alpha dimerization and DNA binding. This mutation was not found in 214 unrelated nondiabetic subjects (53 Japanese, 53 Chinese, 51 white, and 57 African-American). The R127W mutation was only present in three of five diabetic members in this family, indicating that it is not the only cause of diabetes in this family. The remaining seven nucleotide substitutions were located in the proximal promoter region and introns. They are not predicted to affect the transcription of the gene or mRNA processing and represent polymorphisms and rare variants. The results suggest that mutations in the HNF-4 alpha gene may cause early-onset NIDDM/MODY in Japanese but they are less common than mutations in the HNF-1 alpha/MODY3 gene. The information on the sequence of the HNF-4 alpha gene and its promoter region will facilitate the search for mutations in other populations and studies of the role of this gene in determining normal pancreatic beta-cell function.

Alternative Splicing↗

PubMed1996

Early appearance of abnormality of microperoxisomal enzymes in the cerebral cortex of senescence-accelerated mouse.

SAMP8, a substrain of senescence-accelerated mouse (SAM), has been characterized by several age-related deficits in the brain. Previously, we reported that the contents of lipid peroxides and protein carbonyl, and net generation of H2O2 were increased in the cerebral cortex of SAMP8 at 4-8 weeks of age in comparison with those in age-matched SAMR1 substrain used as a control. To study the cause of these increases, we compared the activities of antioxidative enzymes in the cerebral cortex between the two substrains. The catalase activity was decreased by 75% in SAMP8 at 4-8 weeks of age, whereas neither superoxide dismutase nor glutathione peroxidase activities were changed. The change in the catalase activity was seen only in the cerebral cortex where oxidative stress was increased in SAMP8. On the contrary, the activity of acyl-CoA oxidase, a microperoxisomal H2O2-producing enzyme, in the cerebral cortex of SAMP8 was increased 1.6 fold in comparison with that in age-matched SAMR1 without change in the activity of D-amino acid oxidase. Furthermore, the changes in the activities of catalase and acyl-CoA oxidase with age were paralleled with those observed in oxidative stress in SAMP8. These results suggest that the abnormality of activities in two microperoxisomal enzymes, catalase and acyl-CoA oxidase, may be one of the cause of the early increase in oxidative stress observed in the cerebral cortex of 4-8 weeks old SAMP8.

Acyl-CoA Oxidase↗

PubMed1996

Mutations in the hepatocyte nuclear factor-1alpha gene in maturity-onset diabetes of the young (MODY3)

The disease non-insulin-dependent (type 2) diabetes mellitus (NIDDM) is characterized by abnormally high blood glucose resulting from a relative deficiency of insulin. It affects about 2% of the world's population and treatment of diabetes and its complications are an increasing health-care burden. Genetic factors are important in the aetiology of NIDDM, and linkage studies are starting to localize some of the genes that influence the development of this disorder. Maturity-onset diabetes of the young (MODY), a single-gene disorder responsible for 2-5% of NIDDM, is characterized by autosomal dominant inheritance and an age of onset of 25 years or younger. MODY genes have been localized to chromosomes 7, 12 and 20 (refs 5, 7, 8) and clinical studies indicate that mutations in these genes are associated with abnormal patterns of glucose-stimulated insulin secretion. The gene on chromosome 7 (MODY2) encodes the glycolytic enzyme glucokinases which plays a key role in generating the metabolic signal for insulin secretion and in integrating hepatic glucose uptake. Here we show that subjects with the MODY3-form of NIDDM have mutations in the gene encoding hepatocyte nuclear factor-1alpha (HNF-1alpha, which is encoded by the gene TCF1). HNF-1alpha is a transcription factor that helps in the tissue-specific regulation of the expression of several liver genes and also functions as a weak transactivator of the rat insulin-I gene.

Animals↗

PubMed1996

Mutations in the hepatocyte nuclear factor-4alpha gene in maturity-onset diabetes of the young (MODY1)

The disease maturity-onset diabetes of the young (MODY) is a genetically heterogeneous monogenic form of non-insulin-dependent (type 2) diabetes mellitus (NIDDM), characterized by early onset, usually before 25 years of age and often in adolescence or childhood, and by autosomal dominant inheritance. It has been estimated that 2-5% of patients with NIDDM may have this form of diabetes mellitus. Clinical studies have shown that prediabetic MODY subjects have normal insulin sensitivity but suffer from a defect in glucose-stimulated insulin secretion, suggesting that pancreatic beta-cell dysfunction rather than insulin resistance is the primary defect in this disorder. Linkage studies have localized the genes that are mutated in MODY on human chromosomes 20 (MODY1), 7 (MODY2) and 12 (MODY3), with MODY2 and MODY3 being allelic with the genes encoding glucokinase, a key regulator of insulin secretion, and hepatocyte nuclear factor-1alpha (HNF-1alpha), a transcription factor involved in tissue-specific regulation of liver genes but also expressed in pancreatic islets, insulinoma cells and other tissues. Here we show that MODY1 is the gene encoding HNF-4alpha (gene symbol, TCF14), a member of the steroid/thyroid hormone receptor superfamily and an upstream regulator of HNF-1alpha expression.

Adult↗

PubMed1996

Arrested DNA replication in Xenopus and release by Escherichia coli mutagenesis proteins.

Xenopus oocytes and oocyte nuclear extracts repair ultraviolet photoproducts on double-stranded (ds) DNA and replicate single-stranded (ss) to ds DNA. M13 ss DNA molecules containing cyclobutane pyrimidine dimers were maintained but not replicated in Xenopus oocytes yet were replicated in progesterone-matured oocytes. The replication arrest functioned only in cis. The replication arrest was alleviated by injection into oocytes of messenger RNAs encoding the prokaryotic mutagenesis proteins UmuD'C or MucA'B. These results may help explain how cells stabilize repair or replication events on DNA with unrepairable lesions.

Animals↗

PubMed1996

DNA polymerases alpha and beta are required for DNA repair in an efficient nuclear extract from Xenopus oocytes.

Xenopus oocytes and an oocyte nuclear extract efficiently repair the bulky DNA lesions cyclobutane pyrimidine dimers,(6-4) photoproducts, and N-acetoxy-2-aminofluorene (AAF) adducts by an excision repair mechanism. Nearly all (>95%) of the input damaged DNA was repaired within 5 h in both injected cells and extracts with no significant incorporation of label into control undamaged DNA. Remarkably, more than 10(10) cyclobutane pyrimidine dimers or(6-4) photoproducts are repaired/nuclei. The extracts are free from nuclease activity, and repair is independent of exogenous light. Both the high efficiency and DNA polymerase requirements of this system appear to be different from extracts derived from human cells. We demonstrated a requirement for DNA polymerases alpha and beta in repair of both photoproducts and AAF by inhibiting repair with several independent antibodies specific to either DNA polymerases alpha or beta and then restoring repair by adding the appropriate purified polymerase. Repair is inhibited by aphidicolin at concentrations specific for blocking DNA polymerase alpha and dideoxynucleotide triphosphates at concentrations specific for inhibiting DNA polymerase beta.

Animals↗

PubMed1996

Early and transient increase in oxidative stress in the cerebral cortex of senescence-accelerated mouse.

Age-related changes in oxidative stress in the cerebral cortex of SAMP8, a substrain of senescence-accelerated mouse (SAM), were investigated in comparison with those in SAMR1, which were used as a control. The lipid peroxide and protein carbonyl contents were transiently increased in SAMP8 from 4- to 8-weeks of age. The increases in lipid peroxide were seen only in the cerebral cortex and not in other regions of the cerebrum. Furthermore, the net generation of reactive oxygen species in cerebral cells was also increased in SAMP8. In addition, the activity of glutamine synthetase, which is known as an enzyme-highly sensitive to reactive oxygen, was decreased in the cerebral cortex of SAMP8 from 4- to 8-weeks of age. These results suggest that oxidative stress may be induced in the cerebral cortex of SAMP8 from 4- to 8-weeks of age, preceding the appearance of distinctive deficits in the brain of SAMP8.

Aging↗