Toshio Kahara

Prediction of exercise-mediated changes in metabolic markers by gene polymorphism

The effects of regular physical exercise on obesity-associated metabolic abnormalities vary for each individual. In this study, we investigated whether genotypes of genes associated with obesity can predict the effects of exercise on changes in metabolic markers in healthy men. Healthy Japanese men (n=106) performed the exercise program at 50% of their maximal heart rate for 20-60 min a day, 2-3 days each week for 3 months. The levels of fasting plasma glucose (FPG) and serum leptin significantly decreased after the exercise program. Polymorphisms of the beta3-adrenergic receptor (beta3AR) and uncoupling protein-1 (UCP-1) genes were analyzed with RFLP methods. In the Trp/Trp genotype of the beta3AR gene, the levels of serum leptin, FPG and fructosamine (FrAm) decreased significantly after the exercise program, but not in the Arg/Arg genotype. In the AG heterozygote and the GG homozygote of the UCP-1 gene, FPG and FrAm levels were significantly reduced, respectively. In conclusion, gene polymorphism of the beta3AR and UCP-1 was found to be associated with the exercise-mediated improvement in glucose tolerance and leptin resistance in healthy Japanese men.

Extramedullary plasmacytoma in the adrenal incidentaloma

High‐resolution imaging has led to the increasingly frequent discovery of adrenal incidentalomas. Most are nonfunctioning tumours and adenomas, but it is difficult to distinguish benign from malignant tumours using only morphological and laboratory data, and the diagnosis often remains uncertain without histological examination. Here we report the case of a 52‐year‐old Japanese man who had a right adrenal incidentaloma 4 cm in diameter. The tumour was removed by laparoscopic adrenalectomy. The pathology specimen revealed the typical histology of plasmacytoma. Extramedullary plasmacytoma is a very rare type of plasma cell proliferative disorder. This is the first documented case of an extramedullary plasmacytoma in the adrenal gland.

Thyroglobulin Gene Mutation with Cold Nodule on Thyroid Scintigraphy

Thyroglobulin gene mutation is a rare cause of congenital hypothyroidism, but thyroglobulin gene mutations are thought to be associated with thyroid cancer development. A 21-year-old Japanese man treated with levothyroxine for congenital hypothyroidism had an enlarged thyroid gland with undetectable serum thyroglobulin despite elevated serum TSH level. The patient was diagnosed with thyroglobulin gene mutation, with compound heterozygosity for Gly304Cys missense mutation and Arg432X nonsense mutation. Ultrasonography showed a hypovascular large tumor in the left lobe that appeared as a cold nodule on thyroid scintigraphy. He underwent total thyroidectomy, but pathological study did not reveal findings of thyroid carcinoma, but rather a hyperplastic nodule with hemorrhage. Strong cytoplasmic thyroglobulin immunostaining was observed, but sodium iodide symporter immunostaining was hardly detected in the hyperplastic nodule. The clinical characteristics of patients with thyroglobulin gene mutations are diverse, and some patients are diagnosed by chance on examination of goiter in adults. The presence of thyroid tumors that appear as cold nodules on thyroid scintigraphy should consider the potential for thyroid carcinoma, if the patient has relatively low serum thyroglobulin concentration in relation to the degree of TSH without thyroglobulin autoantibody.

Autoimmune polyglandular syndrome type 3 with anorexia.

A 71-year-old man with diabetes mellitus visited our hospital with complaints of anorexia and weight loss (12 kg/3 months). He had megaloblastic anemia, cobalamin level was low, and autoantibody to intrinsic factor was positive. He was treated with intramuscular cyanocobalamin, and he was able to consume meals. GAD autoantibody and ICA were positive, and he was diagnosed with slowly progressive type 1 diabetes mellitus (SPIDDM). Thyroid autoantibodies were positive. According to these findings, he was diagnosed with autoimmune polyglandular syndrome type 3 with SPIDDM, pernicious anemia, and Hashimotos thyroiditis. Extended periods of cobalamin deficiency can cause serious complications such as ataxia and dementia, and these complications may not be reversible if replacement therapy with cobalamin is delayed. Although type 1 diabetes mellitus with coexisting pernicious anemia is very rare in Japan, physicians should consider the possibility of pernicious anemia when patients with diabetes mellitus have cryptogenic anorexia with the finding of significant macrocytosis (MCV > 100 fL).