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To understand the etiology of metabolic disorders, including obesity and type II diabetes, it is essential to gain better insight into how stored and available energy sources are monitored by the central nervous system. In particular, a comprehension of the fine cellular interplay and intracellular mechanisms that enable appropriate hypothalamic and consequent endocrine and behavioral responses to both circulating hormonal and nutrient signals remains elusive. Recent data, including those from our laboratories, raised the notion that reactive oxygen species (ROS) generation is not merely a by-product of substrate oxidation, but it plays a crucial role in modulating cellular responses involved in the regulation of energy metabolism. These review summarizes the published recent data on the effect of ROS levels in the regulation of neuronal function, including that of hypothalamic melanocortin neurons, pro-opiomelanocortin and neuropeptide Y-/agouti related peptide-neurons, in the modulation of food intake.
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Autophagy plays a crucial role in the maintenance of cellular nutrient balance and the function of organelles such as mitochondria or the endoplasmic reticulum, which are important in intracellular metabolism, insulin release, and insulin sensitivity. In the insulin-producing pancreatic β-cells, autophagy is important in the maintenance of β-cell mass, structure, and function. Mice with deficiencies in β-cell-specific autophagy show reduced β-cell mass and defects in insulin secretion that lead to hypoinsulinemia and hyperglycemia but not diabetes. However, these mice developed diabetes when bred with
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The majority of the vitamin D in our body is produced by cutaneous synthesis in response to sunlight. As more and more people live in cities and spend the bulk of their time indoors, it can be difficult to get sufficient sun exposure for adequate cutaneous production of vitamin D. Therefore, vitamin D insufficiency has become a very common health problem worldwide. The Korea National Health and Nutrition Examination Survey IV 2008 showed that the prevalence of vitamin D insufficiency, defined as a serum 25-hydroxyvitamin D [25(OH)D] level below 50 nmol/L, was 47.3% in males and 64.5% in females. Only 13.2% of males and 6.7% of females had a serum 25(OH)D level of greater than 75 nmol/L. In Korea, vitamin D insufficiency was more prevalent in young adults than in elderly people, likely due to the indoor lifestyle of younger people. Compared with the United States and Canada, Korea has a lower mean 25(OH)D level and a higher prevalence of vitamin D insufficiency. To improve the vitamin D status of the Korean population, more aggressive policies on food fortification and vitamin D supplementation are needed.
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Adrenal incidentaloma is an adrenal neoplasm frequently encountered in clinical practice for which detection rates have recently increased. We describe here the clinical characteristics of adrenal incidentalomas.
A retrospective study was performed examining the age, sex, location, size, function, and the histological findings for 348 patients with an adrenal mass discovered incidentally on computed tomography (CT) undertaken for health examination or nonadrenal disease from August 2005 to May 2012.
Patients consisted of 156 males (44.8%) and 192 females (55.2%), aged between 20 and 86. Adrenal masses were most commonly found in patients in their sixth decade (32.5%). Regarding the location of the masses, 62.0% were found in the left adrenal gland, 30.2% were found in the right, and 7.8% were found bilaterally. Of all of the masses analyzed, 87.1% were 1 to 4 cm in size, and an adenoma-like appearance was the most common finding (75.3%) seen on CT scans. Hormonal analysis showed that 82.2% of the masses were nonfunctioning, 6.0% were diagnosed as subclinical Cushing's syndrome, 4.6% were aldosterone-producing adenomas, and 7.2% were pheochromocytomas. Adrenalectomy was performed in a total of 69 patients having adenoma (50.7%), pheochromocytoma (24.6%), and carcinoma (4.3%).
The characteristics of benign, malignant, nonfunctional, and functional adrenal masses that were incidentally found at our hospital were similar to those presented in other studies.
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Serum albumin has been suggested to be associated with insulin resistance. We evaluated the association between serum albumin concentration and insulin resistance. We also investigated whether serum albumin level has an independent effect on the development of diabetes.
In our study, 9,029 subjects without diabetes, who underwent comprehensive health check-ups annually for 5 years, were categorized into tertiles based on their serum albumin levels at baseline. The odds ratio (OR) for the prevalence of insulin resistance, defined as the top quartile of homeostasis model assessment of insulin resistance and the presence of impaired fasting glucose and nonalcoholic fatty liver disease, was evaluated cross-sectionally. Also, the hazard ratio (HR) for incident diabetes was estimated longitudinally, according to the baseline albumin tertiles using Cox proportional hazard analysis respectively.
From the lowest to the highest tertile of albumin, the multivariable-adjusted ORs of insulin resistance increased significantly in both men and women. During the mean follow-up period of nearly 4 years, 556 (6.1%) subjects progressed to diabetes. The multivariable-adjusted HR (95% confidence interval [CI]) of diabetes in men were 1, 1.09 (95% CI, 0.86 to 1.40), and 1.10 (95% CI, 0.86 to 1.41), respectively, from the lowest to the highest tertiles of baseline albumin. Corresponding values for women were 1, 1.21 (95% CI, 0.66 to 2.21), and 1.06 (95% CI, 0.56 to 2.02), respectively.
Our study showed that increased serum albumin level was associated with insulin resistance. However, serum albumin did not have an independent effect on the development of diabetes.
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The Product of Red Blood Cells and Hematocrit Can Be Used as a Novel Indicator of Impaired Fasting Blood Glucose Status
We investigated the association of coronary artery calcium score (CACS) with body composition and insulin resistance in apparently healthy Korean adults.
Nine hundred forty-five participants (mean age, 48.9 years; 628 men) in a medical check-up program were selected for analysis. Body composition was assessed by bioelectrical impedance analysis (BIA). Insulin resistance was evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR). The CACS was assessed by multidetector computed tomography.
One hundred forty-six subjects (15.4%) showed coronary artery calcification and 148 subjects (15.7%) had metabolic syndrome. CACS showed a significant positive correlation with age, fasting glucose level, waist circumference (WC), blood pressure, hemoglobin A1c, HOMA-IR, and waist-hip ratio (WHR) assessed by BIA. CACS had a negative correlation with high density lipoprotein cholesterol (HDL-C). Subjects with high CACS showed significantly higher mean WHRs and lower mean values for lean body mass compared with subjects without coronary artery calcification. In logistic regression analyses with coronary artery calcification as the dependent variable, the highest quartile of WHR showed a 3.125-fold increased odds ratio for coronary artery calcification compared with the lowest quartile after adjustment for confounding variables. When receiver operating characteristics analyses were performed with coronary artery calcification as the result variable, WHR showed the largest area under the curve (AUC) value among other variables except for age and WC in women (AUC=0.696 for WHR, 0.790 for age, and 0.719 for WC in women).
In our study population of apparently healthy Korean adults, WHR was the most significant predictor for coronary artery calcification among other confounding factors, suggesting that it may have implication as a marker for early atherosclerosis.
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Tumor necrosis factor (TNF)-α is associated with insulin resistance and systemic inflammatory responses. The aim of this study was to investigate the relationship between TNF-α and the development of nonalcoholic fatty liver disease (NAFLD) in a longitudinal study.
Three hundred and sixty-three apparently healthy subjects (mean age, 40.5±6.1 years; male, 57.6%) without NAFLD were enrolled in 2003. Anthropometric and laboratory measurements were performed. The participants were grouped into tertiles according to their serum TNF-α levels from samples taken in 2003. At a 4-year follow-up, we compared the odds ratios (ORs) of the development of NAFLD according to the tertiles of TNF-α levels measured in 2003.
At the 4-year follow-up, the cumulative incidence of NAFLD was 29.2% (106/363). The group that developed NAFLD had higher levels of TNF-α than those in the group without NAFLD (3.65±1.79 pg/mL vs. 3.15±1.78 pg/mL;
Higher serum TNF-α levels in subjects without NAFLD were associated with the development of NAFLD. The results of study might suggest a pathologic role of inflammation in NAFLD.
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Sarcopenia Is an Independent Risk Factor for NAFLD in COPD: A Nationwide Survey (KNHANES 2008–2011)
Cancer metastases to the thyroid or adrenal gland are uncommon. Furthermore, cases showing long-term survival after surgical resection of those metastatic tumors are rare. We report a case of pulmonary artery intimal sarcoma with metastases to the thyroid and adrenal glands sequentially that was successfully treated with sequential metastasectomies. A 62-year-old woman presented with a 4-week history of dyspnea on exertion and facial edema in November 1999. Echocardiography and chest computed tomography (CT) revealed an embolism-like mass in the pulmonary trunk. Pulmonary artery endarterectomy with pulmonary valve replacement was performed, and histopathology revealed pulmonary artery intimal sarcoma. A thyroid nodule was found by chest CT in November 2001 (2 years after initial surgery). During follow-up, this lesion showed no change, but we decided to obtain fine needle aspiration cytology (FNAC) in August 2004 (4.7 years after initial surgery). FNAC revealed atypical spindle cells suggestive of metastatic intimal sarcoma. She underwent total thyroidectomy. During follow-up, a right adrenal gland mass was detected by chest CT in March 2006 (6.3 years after initial surgery), and adrenalectomy was done, which also revealed metastatic sarcoma. She has been followed up without any evidence of recurrent disease until May 2012 (12.5 years after initial surgery).
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Acute suppurative thyroiditis (AST) is a rare condition, as the thyroid gland is relatively resistant to infection. Thyroid function tests are usually normal in AST. A few cases of AST associated with thyrotoxicosis have been reported in adults. We report a case of AST that was associated with thyrotoxicosis in a 70-year-old woman. We diagnosed AST with thyroid ultrasonography and fine needle aspiration of pus. The patient improved after surgical intervention and had no anatomical abnormality. Fine needle aspiration is the best method for the difficult task of differentiating malignancy and subacute thyroiditis from AST with thyrotoxicosis. Earlier diagnosis and proper treatment for AST might improve the outcome.
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We report here the cases of two females with Graves' disease who developed insulin autoimmune syndrome after treatment with methimazole. The patients exhibited a sudden altered mental state after treatment with methimazole for approximately 4 weeks. Patients had hypoglycemia with serum glucose below 70 mg/dL, and laboratory findings showed both high levels of serum insulin and high titers of insulin autoantibodies. The two women had never been exposed to insulin or oral antidiabetic agents, and there was no evidence of insulinoma in imaging studies. After glucose loading, serum glucose, and total insulin levels increased abnormally. One of the patient was found to have HLA-DRB1*0406, which is known to be strongly associated with methimazole-induced insulin autoimmune syndrome. After discontinuation of methimazole, hypoglycemic events disappeared within 1 month. Insulin autoantibody titer and insulin levels decreased within 5 months and there was no further development of hypoglycemic events. We present these cases with a review of the relevant literature.
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Radioactive iodine (RAI) therapy has been used as a treatment option for Graves' disease, and it has been widely accepted to be safe. On the other hand, some evidence suggests that RAI therapy is possibly associated with a small increased risk of thyroid cancer. Herein, we report a rare case of anaplastic thyroid carcinoma (ATC) associated with Graves' disease, following RAI treatment. A 42-year-old woman had been diagnosed with Graves' disease and although she was treated with an antithyroid drug, she remained in a hyperthyroid state, which led to two RAI treatments. More than 10 years later, the patient revisited our clinic due to hoarseness, dysphagia, and dyspnea, which had lasted for 2 months. Neck computed tomography suggested thyroid carcinoma and a lymph node biopsy showed metastatic papillary carcinoma. The patient underwent total thyroidectomy and was finally diagnosed as having an ATC. It is not clear if the occurrence of ATC reported here was influenced by the RAI therapy or alternatively, it may only represent the delayed recognition of a rare change in the natural history of Graves' disease. Nevertheless, this report is worthwhile since it presents a very rare case of ATC that occurred eleven years after the RAI therapy for Graves' disease.
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We report the case of a 36-year-old woman who presented with headache, fever, and amenorrhea. Laboratory analysis revealed hypopituitarism and autoimmune thyroiditis, while a cerebrospinal fluid study suggested concurrent aseptic meningitis. A magnetic resonance image (MRI) scan revealed a 1.0×0.9 cm cystic mass enlarging the sella turcica. Surgical resection via an endoscopic transsphenoidal route was performed. The histological finding of the excised tissue revealed foamy histiocytes with vacuolated cytoplasm, supporting the diagnosis of xanthomatous hypophysitis. Although a residual soft lesion was observed on the MRI image postoperatively, the patient's headache and fever improved. Ten months after surgery, the patient complained of visual impairment and headache, and the residual mass had enlarged into the suprasellar area. High dose (500 mg intravenous) methylprednisolone was administered for 3 days. During the methylprednisolone pulse therapy, the patient's visual acuity and headache improved. A follow-up MRI taken after methylprednisolone therapy showed a marked mass reduction. Our case supports an autoimmune pathophysiology for xanthomatous hypophysitis and suggests that high dose glucocorticoid therapy as a treatment option.
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Atypical antipsychotics have replaced conventional antipsychotics in the treatment of schizophrenia because they have less of a propensity to cause undesirable neurologic adverse events including extrapyramidal symptoms, tardive dyskinesia, and neuroleptic malignant syndrome (NMS). However, atypical antipsychotics have been known to result in various metabolic complications such as impaired glucose tolerance, diabetes and even diabetic ketoacidosis (DKA). In addition, a number of NMS cases have been reported in patients treated with atypical antipsychotics, although the absolute incidence of neurologic side effects is currently significantly low. Here, we report a patient who simultaneously developed DKA, acute renal failure and NMS with rhabdomyolysis after olanzapine treatment. Olanzapine-induced metabolic complications and NMS were dramatically improved with cessation of the olanzapine treatment and initiation of supportive management including fluid therapy, hemodialysis, and intensive glycemic control using insulin. At short-term follow-up, insulin secretion was markedly recovered as evidenced by a restoration of serum C-peptide level, and the patient no longer required any hypoglycemic medications. Despite the dramatic increase in the use of atypical antipsychotics treatment, individualized treatments along with careful monitoring may be prudent for high risk or vulnerable patients in order to avoid the development of metabolic side effects.
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