Recent surge of thyroid cancer, especially papillary thyroid carcinoma (PTC), ignited a debate on over-diagnosis of cancer. Such increase in incidence is a worldwide phenomenon, but it has been the most prominent in Korea. Although increased detection might have played a major role, some evidences suggest that true increase in incidence have also contributed to such phenomenon. PTC is a very common disease being the most common cancer in human. As the mortality due to PTC is relatively low, understanding pathophysiology of the disease and risk prediction in individual patient have particular importance for optimal management, but little has been known. I suggest a reason for such a commonality of PTC, and would like to describe my view on some aspects of PTC including unresolved issue on management based on our recent observations.
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Cushing's disease (CD) is a rare disorder characterized by the overproduction of adrenocorticotropic hormone due to a pituitary adenoma that ultimately stimulates excessive cortisol secretion from the adrenal glands. Prior to the detection of pituitary adenomas, various clinical signs of CD such as central obesity, moon face, hirsutism, and facial plethora are usually already present. Uncontrolled hypercortisolism is associated with metabolic, cardiovascular, and psychological disorders that result in increased mortality. Hence, the early detection and treatment of CD are not only important but mandatory. Because its clinical manifestations vary from patient to patient and are common in other obesity-related conditions, the precise diagnosis of CD can be problematic. Thus, the present set of guidelines was compiled by Korean experts in this field to assist clinicians with the screening, diagnoses, and treatment of patients with CD using currently available tests and treatment modalities.
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Denosumab, a fully human recombinant monoclonal antibody to the receptor activator of nuclear factor-κB ligand (RANKL), blocks binding of RANKL to the RANK receptor, found on the surface of osteoclasts and osteoclast precursors, resulting in decreased bone resorption. Subcutaneous denosumab administration once every 6 months increases bone mineral density at the lumbar spine, total hip, and/or femoral neck, and reduces markers of bone turnover significantly in postmenopausal women with osteoporosis. Relative to placebo, denosumab treatment reduces the risk of vertebral, nonvertebral, and hip fractures significantly. The benefits of denosumab treatment are generally obvious after the first dose and were continued for up to 8 years of treatment in an extension study. The tolerability profile of denosumab during this extension phase was consistent with that observed during the initial 3-year FREEDOM trial. Postmarketing safety surveillance has not shown any unexpected findings. Ongoing safety surveillance will more fully define the long-term safety of denosumab. The benefits of denosumab would seem to be greater than its risks. Denosumab is an important choice in the treatment of postmenopausal women with osteoporosis at increased risk of fractures, including older patients who have difficulty with oral bisphosphonate intake and patients who are intolerant of, or unresponsive to, other therapies.
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The association between calcium supplementation and adverse cardiovascular events has recently become a topic of debate due to the publication of two epidemiological studies and one meta-analysis of randomized controlled clinical trials. The reports indicate that there is a significant increase in adverse cardiovascular events following supplementation with calcium; however, a number of experts have raised several issues with these reports such as inconsistencies in attempts to reproduce the findings in other populations and questions concerning the validity of the data due to low compliance, biases in case ascertainment, and/or a lack of adjustment. Additionally, the Auckland Calcium Study, the Women's Health Initiative, and many other studies included in the meta-analysis obtained data from calcium-replete subjects and it is not clear whether the same risk profile would be observed in populations with low calcium intakes. Dietary calcium intake varies widely throughout the world and it is especially low in East Asia, although the risk of cardiovascular events is less prominent in this region. Therefore, clarification is necessary regarding the occurrence of adverse cardiovascular events following calcium supplementation and whether this relationship can be generalized to populations with low calcium intakes. Additionally, the skeletal benefits from calcium supplementation are greater in subjects with low calcium intakes and, therefore, the risk-benefit ratio of calcium supplementation is likely to differ based on the dietary calcium intake and risks of osteoporosis and cardiovascular diseases of various populations. Further studies investigating the risk-benefit profiles of calcium supplementation in various populations are required to develop population-specific guidelines for individuals of different genders, ages, ethnicities, and risk profiles around the world.
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Osteoclasts are multinucleated cells formed mainly on bone surfaces in response to cytokines by fusion of bone marrow-derived myeloid lineage precursors that circulate in the blood. Major advances in understanding of the molecular mechanisms regulating osteoclast formation and functions have been made in the past 20 years since the discovery that their formation requires nuclear factor-kappa B (NF-κB) signaling and that this is activated in response to the essential osteoclastogenic cytokine, receptor activator of NF-κB ligand (RANKL), which also controls osteoclast activation to resorb (degrade) bone. These studies have revealed that RANKL and some pro-inflammatory cytokines, including tumor necrosis factor, activate NF-κB and downstream signaling, including c-Fos and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), and inhibition of repressors of NFATc1 signaling, to positively regulate osteoclast formation and functions. However, these cytokines also activate NF-κB signaling that can limit osteoclast formation through the NF-κB signaling proteins, TRAF3 and p100, and the suppressors of c-Fos/NFATc1 signaling, IRF8, and RBP-J. This paper reviews current understanding of how NF-κB signaling is involved in the positive and negative regulation of cytokine-mediated osteoclast formation and activation.
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Relationship Between Metabolic Syndrome and Bone Health – An Evaluation of Epidemiological Studies and Mechanisms Involved
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Mutations in centrosomal protein genes have been identified in a number of genetic diseases in brain development, including microcephaly. Centrosomal P4.1-associated protein (CPAP) is one of the causal genes implicated in primary microcephaly. We previously proposed that CPAP is essential for mother centriole maturation during mitosis.
We immunostained CPAP-depleted cells using the ninein antibody, which selectively detects subdistal appendages in mature mother centrioles.
Ninein signals were significantly impaired in CPAP-depleted cells.
The results suggest that CPAP is required for mother centriole maturation in mammalian cells. The selective absence of centriolar appendages in young mother centrioles may be responsible for asymmetric spindle pole formation in CPAP-depleted cells.
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Sclerostin is a secreted Wnt inhibitor produced almost exclusively by osteocytes, which inhibits bone formation. Aromatase inhibitors (AIs), which reduce the conversion of steroids to estrogen, are used to treat endocrine-responsive breast cancer. As AIs lower estrogen levels, they increase bone turnover and lower bone mass. We analyzed changes in serum sclerostin levels in Korean women with breast cancer who were treated with an AI.
We included postmenopausal women with endocrine-responsive breast cancer (
Postmenopausal women with breast cancer had significantly higher sclerostin levels compared to those in premenopausal women (27.8±13.6 pmol/L vs. 23.1±4.8 pmol/L,
Serum sclerostin levels increased with absolute deficiency of residual estrogens in postmenopausal women with endocrine-responsive breast cancer who underwent AI therapy with concurrent bone loss.
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Damaged mitochondria are removed by autophagy. Therefore, impairment of autophagy induces the accumulation of damaged mitochondria and mitochondrial dysfunction in most mammalian cells. Here, we investigated mitochondrial function and the expression of mitochondrial complexes in autophagy-related 7 (
To evaluate the effect of autophagy deficiency on mitochondrial function in pancreatic β-cells, we isolated islets from
Baseline oxygen consumption rate of
Impairment of autophagy in pancreatic β-cells suppressed the expression of some mitochondrial respiratory complexes, and may contribute to mitochondrial dysfunction. Among the complexes, I and II seem to be most vulnerable to autophagy deficiency.
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Thyroid incidentalomas detected by 2-deoxy-2-18F-fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) have been reported in 1% to 4% of the population, with a risk of malignancy of 27.8% to 74%. We performed a retrospective review of FDG-avid thyroid incidentalomas in cancer screening subjects and patients with nonthyroid cancer. The risk of malignancy in thyroid incidentaloma and its association with the maximal standardized uptake value (SUVmax) in 18F-FDG PET/CT were evaluated to define the predictor variables in assessing risk of malignancy.
A total of 2,584 subjects underwent 18F-FDG PET/CT for metastatic evaluation or cancer screening from January 2005 to January 2010. Among them, 36 subjects with FDG-avid thyroid incidentalomas underwent further diagnostic evaluation (thyroid ultrasonography-guided fine needle aspiration cytology [FNAC] or surgical resection). We retrospectively reviewed the database of these subjects.
Of the 2,584 subjects who underwent 18F-FDG PET/CT (319 for cancer screening and 2,265 for metastatic evaluation), 52 (2.0%) were identified as having FDG-avid thyroid incidentaloma and cytologic diagnosis was obtained by FNAC in 36 subjects. Of the subjects, 15 were proven to have malignant disease: 13 by FNAC and two by surgical resection. The positive predictive value of malignancy in FDG-avid thyroid incidentaloma was 41.7%. Median SUVmax was higher in malignancy than in benign lesions (4.7 [interquartile range (IQR), 3.4 to 6.0] vs. 2.8 [IQR, 2.6 to 4.0],
Thyroid incidentalomas found on 18F-FDG PET/CT have a high risk of malignancy, with a positive predictive value of 41.7%. FDG-avid thyroid incidentalomas with higher SUVmax tended to be malignant.
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Metformin is considered the first choice oral treatment for type 2 diabetes patients in the absence of contraindications. Rarely, life-threatening complications associated with metformin treatment are seen in some patients with underlying diseases. The aim of this study was to further investigate the clinical profiles and risk factors for metformin-associated lactic acidosis (MALA) and the treatment modalities according to survival.
To identify MALA, we performed a retrospective study in seven diabetic patients who were taking metformin and had been diagnosed with lactic acidosis at Inha University Hospital between 1995 and 2012. For each patient, we recorded the age, sex, daily metformin dosage, laboratory test results, admission diagnosis, and risk factors. Also, concurrent conditions, treatment modalities, and outcomes were evaluated.
Six patients had risk factors for lactic acidosis before admission. All patients had renal impairment on admission as a precipitating risk factor. Five patients survived and two patients died despite early renal replacement therapy. Older patients tended to have a poorer prognosis.
Renal function must be monitored in elderly type 2 diabetes mellitus patients with underlying diseases and conditions causing renal impairment who begin metformin treatment. Accurate recognition of MALA and initiation of renal replacement are essential for treatment.
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Sitagliptin is a novel antidiabetic agent with a low risk for hypoglycemia. We investigated the efficacy and safety of sitagliptin when patients switched from a sulfonylurea to sitagliptin and identified good candidates for the switch.
Sixty-one patients with type 2 diabetes switched from glimepiride with metformin to sitagliptin with metformin due to clinical hypoglycemia. Serum glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and 2-hour postprandial plasma glucose (2h-PPG) before and 12 and 24 weeks after the drug switch were checked.
HbA1c and FPG levels did not change 12 or 24 weeks after the switch; however, the 2h-PPG level decreased from 218.0±67.5 mg/dL at baseline to 197.1±69.9 mg/dL at 12 weeks and 192.3±67.4 mg/dL at 24 weeks after switching drugs (
Glycemic control was not aggravated in patients 24 weeks after the drug switch, and symptomatic hypoglycemia decreased significantly. Patients with dominant insulin resistance may be good candidates for switching from a sulfonylurea to sitagliptin to reduce hypoglycemia.
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α TC-6 cells and β TC-1 cells were maintained in Dulbecco's Minimal Essential Medium containing 5 mM glucose and 10% fetal bovine serum. Cells were mixed at a 1:1 ratio (5×105) in 6-well plates and cultured for 24, 48, and 72 hours. After culture, cells were used for insulin and glucagon immunoassays and tested for glucose-stimulated insulin secretion (GSIS).
α TC-6 and β TC-1 cells became condensed by 24 hours and were more strongly compacted after 48 hours. β TC-1 cells showed both β-β and β-α cell contacts. GSIS increased with increasing glucose concentration in co-cultured cells, which showed lower secreted insulin levels than β TC-1 cells alone. The increase in the secreted insulin/insulin content ratio was significantly lower for co-cultured cells than for β-cells alone (
α TC-6 and β TC-1 cells in the co-culture system showed cell-to-cell contacts and a similar stimulated insulin secretion pattern to islets. The co-culture system may be used to better mimic pancreatic islets in
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Autism spectrum disorder (ASD) encompasses a range of disorders that are characterized by social and communication deficits and repetitive behaviors. This study evaluated the effect of methyl-6-(phenylethynyl)-pyridine (MPEP), an antagonist of the mGluR5 metabotropic glutamate receptor, on memory enhancement in the BTBR T+tf/J (BTBR) mouse strain, which has been recognized as a model of ASD.
The pharmacological effects of MPEP on memory and motor coordination were assessed using the Morris water maze and rotarod tests in BTBR and C57BL/6J (B6) mice. Furthermore, we performed morphological analyses of cerebellar foliation in BTBR and B6 mice using hematoxylin and eosin staining.
MPEP-treated BTBR mice exhibited improved learning and memory in the Morris water maze test. MPEP administration also improved motor coordination in the rotarod test. However, no significant difference was observed regarding the numbers of Purkinje cells in the cerebella of BTBR versus normal B6 mice.
This study suggests that the mGluR5 antagonist MPEP has the potential to ameliorate learning and memory dysfunction and impaired motor coordination in BTBR mice. These results further suggest that the BTBR mouse model may be useful in pharmacological studies investigating drugs that could potentially alleviate cognitive dysfunction in ASD.
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