Biomedical subjects

Kenichi Miyako

Publications and source records attributed to Kenichi Miyako.

8 recordsLinked to original sources

PubMed2007

PD-1 gene haplotype is associated with the development of type 1 diabetes mellitus in Japanese children.

Interaction between Programmed cell death-1 (PD-1), a member of costimulatory molecules, and its receptors Programmed cell Death-1 Ligand 1 (PD-L1) and Programmed cell Death-1 Ligand 2 (PD-L2), play an important role in the negative regulation of immune reactions. It was shown that a polymorphism in a regulatory site of the PD-1 gene was associated with susceptibility to several autoimmune diseases in various ethnic groups, whereas the contribution of the PD-1 gene or its ligand genes to the onset of type 1 diabetes (T1D) mellitus in the Japanese population remains unknown. We first screened PD-1, PD-L1, and PD-L2 genes for polymorphisms in the Japanese population, and then investigated the frequencies of polymorphisms in patients with T1D mellitus in comparison with healthy controls. In total, we identified 26 polymorphic sites within these genes, and then 23 polymorphisms with minor allele frequencies greater than 5% were intensively analyzed for genotyping in the patients and the controls. As a result, allele and genotype frequencies of the polymorphism numbers 2, 3, 4, 5, 6, and 8 in the PD-1 gene were different to some extent between the patients and the controls with P < 0.05, which did not reach statistical significance after the correction of multiple comparisons. Allele or genotype frequencies of any SNPs in the PD-L1 or PD-L2 gene did not show differences between the patients and the controls. The frequencies of the estimated haplotypes, those of which consisted of polymorphism numbers 2, 3, 4, 5, 6, and 8 in the PD-1, were significantly different between the patients and the controls (P = 0.00095). The in vitro assessment for a transcription activity of each haplotype of the PD-1 gene by luciferase assay did not demonstrate a functional difference between the haplotypes. In conclusion, the genetic evaluation by association study demonstrated that the PD-1 gene was a predisposing gene to the development of T1D mellitus in the Japanese population.

Adolescent↗

PubMed2005

Vitamin D deficiency rickets caused by improper lifestyle in Japanese children.

BACKGROUND: Nutritional rickets is considered rare in developed countries. However, reports on vitamin D deficiency rickets caused by improper lifestyle have recently increased. The clinical and laboratory characteristics of patients with vitamin D deficiency rickets treated at Fukuoka Children's Hospital, Fukuoka, Japan, were evaluated to clarify current causes and ways to prevent this disease. METHODS: Clinical records were reviewed, and obtained information and data were summarized. RESULTS: Eight patients with vitamin D deficiency rickets (five boys and three girls) were treated during the past 10 years (January 1992 to December 2001). Two infants were referred to the hospital for hypocalcemia and convulsion, and six toddlers (1-2 years old) for bowlegs. One patient lacked exposure to sunlight, and six had an unbalanced diet. The cause of rickets could not be established in one patient. Anthropometric and laboratory data did not indicate malnutrition. Serum alkaline phosphatase was 2518.3 +/- 1401.7 IU/l, calcium was 8.2 +/- 2.6 mg/dL (including 4.7 mg/dL in one infant and 4.8 mg/dL in another), and phosphorus was 4.9 +/- 1.0 mg/dL. High sensitive parathyroid hormone was 1393.1 +/- 321.7 pg/mL (reference range, 180-560), 1,25-dihydroxyvitamin D was 86.0 +/- 61.5 pg/mL (reference range, 20-70), and 25-hydroxyvitamin D was 11.6 +/- 5.6 ng/mL (reference range, 10-30). The patients recovered with a change to a balanced diet, the promotion of weaning, and/or an increase in sunlight exposure. CONCLUSION: Vitamin D deficiency rickets remains a common condition that is best managed by education and disease prevention.

Alkaline Phosphatase↗

PubMed2004

Improved diabetes control by using 'close adjustment algorithms'.

BACKGROUND: Intensive insulin therapy increases the frequency of severe hypoglycemia despite markedly improved glycemic control in patients with type 1 diabetes mellitus. To determine the optimal dose of insulin, the authors designed algorithms based on self-monitored blood glucose levels. METHODS: Each dose of insulin was composed of two components: a basal dose determined on the basis of blood glucose levels over the previous two days and an additional dose determined on the basis of blood glucose level just before insulin injection. The patients were instructed to adjust each dose according to the algorithms. The authors investigated the effects of using algorithms on glycemic control, anthropometric data, body composition, and lipid profile in seven females with type 1 diabetes 12-20 years old. RESULTS: After 3 months, the daily dose of insulin increased significantly from 0.93 +/- 0.18 to 1.16 +/- 0.26 units/kg of body weight, and haemoglobin A(1C) decreased significantly from 8.27 +/- 1.33 to 6.50 +/- 0.64%. Severe hypoglycemia, however, did not occur. Body mass index increased significantly from 21.7 +/- 2.7 to 22.7 +/- 2.9 kg/m(2) with no increase in the percentage of body fat. All lipid-profile data showed a decreasing trend. CONCLUSIONS: Algorithms developed on the basis of self-monitored blood glucose levels are useful in determining the optimal dose of insulin and can improve glycemic control and lipid metabolism.

Algorithms↗

PubMed2004

Two cases of Allgrove syndrome with mutations in the AAAS gene.

Allgrove syndrome is a rare autosomal recessive disorder characterized by the triad of adrenal insufficiency, achalasia and alacrima. This syndrome, also known as triple A syndrome, is now known to be caused by mutations in the AAAS gene. In the present study, we report two new patients of Allgrove syndrome with mutations in the AAAS gene. Patient 1 was a 22-year-old Japanese woman, born to consanguineous parents. She was confirmed to have adrenal insufficiency at the age of 3 years and 6 months. She developed alacrima and bilateral optic nerve atrophy at the age of 8 years. She had been noticed to have dysphagia. Based on these findings, she was diagnosed as having Allgrove syndrome. Mutation analysis revealed a novel homozygous point mutation in exon 7 of her AAAS gene, changing codon 194 encoding Arg (CGA) to a stop codon (TGA) (R194X). Patient 2 was a 7-year-old Japanese boy, born to consanguineous parents. At the age of 1 year, he was noticed to be unable to produce tears. He was confirmed to have adrenal insufficiency, mental retardation and spastic diplegia at the age of 5 years and 4 months. He was tentatively diagnosed as having Allgrove syndrome, although he has never complained of dysphasia. Mutation analysis revealed a homozygous point mutation in exon 4 of his AAAS gene, changing codon 119 encoding Arg (CGA) to a stop codon (TGA) (R119X). Both of the R119X and R194X mutations are predicted to result in truncated and non-functioning ALADIN proteins, and thus the diagnosis of Allgrove syndrome was confirmed by the mutation analyses. These findings indicate that there exist significant clinical variability and mutational heterogeneities in Japanese patients with this syndrome.

Adrenal Insufficiency↗

PubMed2004

Association study of human MTH1 gene polymorphisms with type 1 diabetes mellitus.

Reactive oxygen species are considered to play a role in the development of diabetes mellitus and its complications. Human MTH1 (mutT homologue 1) has 8-oxo-7,8-dihydrodeoxyguanosine triphosphatase activity, which repairs oxidized forms of dGTP. This enzyme is known to have a thermolabile Met83 variant. We examined whether Val83Met polymorphism of human MTH1 gene is associated with type 1 diabetes mellitus. We recruited 156 type 1 diabetic patients (59 males and 97 females). The polymorphism was analyzed by restriction fragment length polymorphism analysis with Nsi I. The Met/Met genotype at codon 83 was very rare in both control and patient groups. Val/Met genotype tended to be more frequent in the whole type 1 diabetic patients than in controls. When subjects were divided into subgroups according to gender, there were no differences in the genotype and allele frequencies between patients and controls in males. On the other hand, in female type 1 diabetic patients, the Val/Met genotype was more frequent than in female controls (corrected P = 0.102). The Met allele was significantly more frequent in female type 1 diabetic patients than in female controls (corrected P = 0.022). Our results suggested that the Met allele at codon 83 of MTH1 gene might be involved in the development of type 1 diabetes mellitus in the Japanese female population.

Adult↗

PubMed2003

Association study between interleukin-12 receptor beta1/beta2 genes and type 1 diabetes or asthma in the Japanese population.

Interleukin-12 (IL-12) secreted from macrophages or dendritic cells plays an important role in the protection against intracellular pathogens as well as the developmental commitment of T helper 1 cells. IL-12 exerts its biological effects through binding to specific IL-12 receptors (IL-12Rs) termed IL-12Rbeta1 and IL 12Rbeta2. In this paper, we performed association studies between the three reported polymorphisms (Q214R, M365T and G378R) of the IL-12Rbeta1 gene or the newly identified polymorphisms (P238L, IVS9 -7G>A, IVS13 -121G>A, A643T, P779P and c.3283T>G) of the IL-12Rbeta2 gene, and the development of type 1 diabetes or atopic asthma as representative Th1- and Th2- dominant diseases, respectively. The association study of each polymorphism of the IL-12Rbeta1 or IL-12Rbeta2 gene and type 1 diabetes or asthma showed that these IL-12R genes did not contribute to the development of type 1 diabetes or asthma in the Japanese population. Further analysis in individuals with susceptibility to intracellular pathogens may elucidate the importance of the IL-12R genes.

Adolescent↗

PubMed2002

Association study of the NRAMP1 gene promoter polymorphism and early-onset type 1 diabetes.

Natural resistance-associated macrophage protein 1 (NRAMP1) has an important role in regulating macrophage functions that affect innate resistance as well as immune responses. We analyzed the microsatellite polymorphism in the promoter region of the human NRAMP1 gene in 206 type 1 diabetes patients and 200 normal children to determine whether this polymorphism might be associated with type 1 diabetes in the Japanese population. The frequency of allele 2 (180 bp) of the promoter microsatellite polymorphism of the NRAMP1gene was slightly lower in the early-onset population (2-10 years of age) of type 1 diabetes patients than in controls, although the difference did not reach statistical significance. The association study of the cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) gene, located near the NRAMP1 gene, and type 1 diabetes showed that the CTLA-4 gene significantly contributed to the development of type 1 diabetes, whereas NRAMP1 had an additional effect on the onset of type 1 diabetes in the young population.

Abatacept↗

PubMed2002

A case of growth hormone and gonadotropin deficiency associated with unilateral anophthalmia, microphallus, cryptorchidism, and mental retardation.

We report a rare case of growth hormone and gonadotropin deficiency associated with dysmorphic features. A 16-year-old boy had left anophthalmia, microphallus, bilateral cryptorchidism, and mental retardation. His chromosomal karyotype was normal, 46, XY. Endocrinological studies revealed growth hormone and gonadotropin deficiency, attributed to hypothalamic dysfunction. Magnetic resonance imaging scan of the head showed a hypoplastic pituitary gland, decreased high intensity signals in the pituitary posterior lobe, absence of the left eye, and a hypoplastic left optic nerve with no abnormality of the pituitary stalk, corpus callosum, or septum pellucidum. Although not completely consistent with the features of septo-optic dysplasia (SOD), his condition was considered within the spectrum of SOD. Despite similarities to the Hesx1 knockout mouse, a model of human SOD, mutation analyses revealed no mutations or polymorphisms in coding regions of any exons or intron-exon boundaries of the HESX1 gene. Further genetic studies of this patient may improve understanding of molecular mechanisms involved in pituitary development.

Adolescent↗