Publications by authors named "Tawata M"

A photoimprint-based immobilization process is presented for cylindrical viruses on the surface of an azobenzene-bearing acrylate polymer by using atomic force microscopy (AFM). Tobacco mosaic virus (TMV), 18 nm in diameter and ca. 300 nm in length, was employed as a model virus.

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Mitochondrial respiratory function in a patient with maternally inherited type 2 diabetes mellitus and hypertrophic cardiomyopathy associated with heteroplasmic mitochondrial DNA (mtDNA) C3310T mutation, which replaces the second amino acid of NADH dehydrogenase 1 (ND1) from a hydrophobic Proline to a hydrophilic Serine, was investigated. Mitochondrial respiratory function solely due to mtDNA C3310T mutation was investigated in cybrid system by the fusion of mtDNA-deleted (rho(0)) HeLa cells and exogenous mtDNA either from the proband or from controls. Total oxygen consumption of the proband cybrid cells was significantly decreased compared with those of controls (2.

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Background: One of the clinical features of myotonic dystrophy is insulin resistance with non-obese diabetes mellitus (DM). Recently, the mechanism of insulin resistance in patients with myotonic dystrophy was revealed. The optimal treatment of DM with myotonic dystrophy has not been established.

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Background: The development of hemiplegia as a result of hypoglycaemia was first described in 1928. However, the mechanism remains unclear.

Case Report: We report a case of a 58-year-old male with diabetes, who developed left hemiplegia during a severe hypoglycaemic event.

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To determine the pathogenicities of mutated mtDNAs in patients with respiration defects, the possible involvement of nuclear DNA mutations has to be excluded, since respiratory function is controlled by both nuclear DNA and mtDNA. This was achieved by showing that the mutated mtDNAs and respiration defects were co-transferred from patients to mtDNA-less human cells, and the resultant cybrid clones carrying mutated mtDNAs expressed respiration defects. To decide whether the cybrid clones expressed respiration defects, in this study the lowest limits of normal respiratory function were evaluated by transfer of mtDNAs from 54 normal subjects to mtDNA-less HeLa cells.

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In order to investigate the effect of high carbohydrate/low fat diet on glucose tolerance and on lipid profiles, we performed a 4-week crossover study. Japanese subjects (30 patients with type 2 diabetes mellitus, 15 subjects with impaired glucose tolerance and 8 subjects with normal glucose tolerance) were allocated either 55% standard carbohydrate/30% fat (sc) or 70% high carbohydrate/15% low fat (hc) diet for four weeks, and evaluated by OGTT and various parameters. Then, the diet was crossed over to another diet, and identical parameters were re-evaluated after four weeks.

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Aim/hypothesis: We analysed Japanese MODY patients for mutations in the HNF-1 alpha gene.

Methods: Fifty unrelated Japanese patients with early-onset diabetes (diagnosed at 25 years of age or younger) or with a strong family history of diabetes were screened for mutations in the HNF-1 alpha gene. Functional studies of the mutant HNF-1alpha were carried out.

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The effect of high carbohydrate (hc) diet on glucose tolerance and on lipid profiles in patients with type 2 diabetes mellitus is contradicted. Japanese patients with mild type 2 diabetes mellitus were allocated either 55% standard carbohydrate (sc) or 80% high carbohydrate diets for 1 week, and OGTT and lipid profiles were examined. Then the diet was crossed over for another week, and OGTT and other identical parameters were re-evaluated.

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Aims/hypothesis: The mouse leptin gene, a major hormonal regulator of appetite and fat cell mass, expresses during the differentiation of 3T3-L1 preadipocytes to adipocytes. To determine if DNA methylation is involved in regulating the expression of the leptin gene, we examined the methylation status and methylation-sensitive transcription factors during 3T3-L1 differentiation.

Methods: DNase I footprinting, electrophoretic mobility-shift assays, and a Southwestern analysis were carried out using nuclear extracts from preadipocytes and adipocytes.

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For determination of whether platelet mtDNA in patients with Parkinson's disease (PD) possesses some lesions to reduce respiratory enzyme activities, platelet mtDNA was transferred into mtDNA-less (rho0) HeLa cells from aged PD patients and age-matched normal subjects, since their activities were controlled by both mitochondrial and nuclear genomes. The resultant mtDNA-repopulated cybrid clones containing the HeLa nuclear genome as a common background were used for comparison of respiratory enzyme activities. Remarkable variations of the enzyme activities were observed in the cybrid clones, irrespective of whether their mtDNA was transferred from normal subjects or PD patients, and some of them showed 20% reduction of average activities.

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A 44-year-old female with familial hypocalciuric hypercalcemia (FHH) due to a homozygous missense mutation (Pro40Ala) in calcium sensing receptor (CaSR) gene has type 2 diabetes mellitus. The identical heterozygous mutation of CaSR gene was observed in consanguineous parents and all other family members examined except her two sisters. Many subjects with abnormal glucose tolerance were observed in this family, which is compatible with maternal inheritance.

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Aldose reductase (AKR1B1) is the first enzyme in the polyol pathway through which glucose is converted to sorbitol, and has been implicated in the etiology of diabetic complications. However, its physiological role is still not well understood. In the kidney, AKR1B1 is quite abundant in the collecting tubule cells and thought to provide protection against hypertonic environment.

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From a family of 16 diabetic patients with typical maternal inheritance, we investigated a 69-year-old woman with type 2 diabetes. The proband showed no major deletions in the mitochondrial DNA (mtDNA). Direct sequencing revealed 7 missense and 5 ribosomal RNA homoplasmic nucleotide substitutions when compared with the Cambridge Sequence and its recent revision.

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A 45-year-old man had been complaining of thirst and polydypsia for the last 3 months and was diagnosed as having type 2 diabetes mellitus because his fasting blood glucose showed 221 mg/dl with positive urinary ketone. He was hospitalized to a private hospital and Penfil 30R was started. However, serum gamma-GTP and aminotransferases began to elevate after insulin treatment and exceeded 1000 IU/l.

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Screening for genetic mutations. A review.

Comb Chem High Throughput Screen

February 2000

A point mutation of a nucleotide within a single gene can have a profound effect on a specific organ and/or the entire human body. DNA sequences associated with human diseases may differ from the corresponding normal sequences by single nucleotide mutations or by large alterations such as deletions, insertions, duplications, or translocations of DNA segments or entire chromosomes. As a result of the heterogeneity of DNA alterations and genetic mutations, various screening approaches are required to detect these alterations.

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Some normal people are falsely classified as having impaired glucose tolerance (IGT) if they are given an oral glucose tolerance test (OGTT) when their last meal contained very few carbohydrates. In this study, the duration of carbohydrate restriction was extended to one and three days and the relationship between the carbohydrate restriction and the glucose tolerance after an OGTT was examined. Two different groups of normal subjects were placed on high-carbohydrate (80% carbohydrates) and low-carbohydrate (10%) diets before an OGTT; one group for one day and the other for 3 days.

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GLUT4, the major glucose transporter in adipose tissue, is expressed during the differentiation of 3T3-L1 cells from preadipocytes to adipocytes. We previously examined the mouse GLUT4 promoter activity up to -590 bp, and demonstrated that the 5'-flanking region of the GLUT4 gene between -200 and -100 bp contains sequences that act as a repressor in preadipocytes, but not in adipocytes. Here we examine in detail the activity of this repressor in 3T3-L1 cells.

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We determined by PCR the number of (A-C)n repeats in the 2. 1 kb upstream of the aldose reductase (AR2) gene in healthy control subjects and in patients with NIDDM in Japanese. Sixty-one patients were recruited based on the severity of retinopathy and subdivided into two groups with proliferative retinopathy and without retinopathy.

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Deficiencies in cellular cyclic AMP (cAMP) and nitric oxide (NO) production are thought to be involved in the pathogenesis of diabetic neuropathy. We used a human neuroblastoma cell line, SH-SY5Y, to investigate the effect of cilostazol, a specific cAMP phosphodiesterase inhibitor, on NO production and Na+, K+-ATPase activity. SH-SY5Y cells were cultured under 5 or 50 mM glucose for 5-6 days, the cells were then exposed to cilostazol or other chemicals and nitrite, cAMP and Na+, K+-ATPase activity were measured.

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Histologic examination of sural nerve of a 32-year-old man with an aggressive polyneuropathy associated with autonomic failure demonstrated amyloid deposition, and familial amyloidotic polyneuropathy (FAP) was diagnosed. Immunohistochemical staining showed transthyretin (TTR) staining of the amyloid deposits in nerve. Sequencing revealed G to A transition in the codon 54 causing TTR Lys 54.

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We reported 56 mitochondrial DNA (mtDNA) mutations in Japanese compared with the Cambridge Sequence by polymerase chain reaction-restriction fragment-single strand conformation polymorphism (PCR-RF-SSCP) analysis. Here we report the principle and the detailed procedures of PCR-RF-SSCP analysis. Restriction map of the 15,673 bp PCR product of mtDNA was designed by MacMolly Tetra, and Hha I and Hinc II were selected.

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The cloning of a G protein-coupled, extracellular calcium-sensing receptor (CaSR) provided direct evidence that Ca(2+)-sensing can occur through receptor-mediated activation of G proteins and their associated downstream regulators of cellular function. CaSR transcripts and protein are present in various tissues that are involved in Ca2+ homeostasis and that do not have well-established roles in Ca balance as well. The physiological relevance of the CaSR has been established by identifying inherited hyper-and hypocalcemia disorders resulting from CaSR mutations: familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism result from inactivating CaSR mutations while autosomal dominant hypocalcemia is caused by activating mutations.

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GLUT4 is the major glucose transporter in adipose tissue and skeletal and cardiac muscles. We examined the mechanisms underlying GLUT4 gene expression in 3T3-L1 cells, which express the gene during their differentiation from preadipocytes to adipocytes. In transient transfections, the activity of a mouse GLUT4 promoter extending to -100 bp in the 5'-flanking region did not differ significantly between 3T3-L1 preadipocytes and adipocytes.

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