Pituitary tumors represent the most common intracranial neoplasms accompanying serious morbidity through mass effects and inappropriate secretion of pituitary hormones. Understanding the etiology of pituitary tumorigenesis will facilitate the development of satisfactory treatment for pituitary adenomas. Although the pathogenesis of pituitary adenomas is largely unknown, considerable evidence indicates that the pituitary tumorigenesis is a complex process involving multiple factors, including genetic and epigenetic changes. This review summarized the recent progress in the study of pituitary tumorigenesis, focusing on the role of tumor suppressor genes, oncogenes and microRNAs.
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The last decade has seen an exponential increase in our understanding of osteocytes function and biology. These cells, once considered inert by-standers trapped into the mineralized bone, has now risen to be key regulators of skeletal metabolism, mineral homeostasis, and hematopoiesis. As tools and techniques to study osteocytes improved and expanded, it has become evident that there is more to these cells than initially thought. Osteocytes are now recognized not only as the key responders to mechanical forces but also as orchestrators of bone remodeling and mineral homeostasis. These cells are the primary source of several important proteins, such as sclerostin and fibroblast growth factor 23, that are currently target as novel therapies for bone loss (as the case for antisclerostin antibodies) or phosphate disorders. Better understanding of the intricate cellular and molecular mechanisms that govern osteocyte biology will open new avenue of research and ultimately indentify novel therapeutics to treat bone and mineral disorders. This review summarizes novel findings and discusses future avenues of research.
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Glucagon-like peptide 1 (GLP-1) is secreted from enteroendocrine L-cells in response to oral nutrient intake and elicits glucose-stimulated insulin secretion while suppressing glucagon secretion. It also slows gastric emptying, which contributes to decreased postprandial glycemic excursions. In the 1990s, chronic subcutaneous infusion of GLP-1 was found to lower blood glucose levels in patients with type 2 diabetes. However, GLP-1's very short half-life, arising from cleavage by the enzyme dipeptidyl peptidase 4 (DPP-4) and glomerular filtration by the kidneys, presented challenges for clinical use. Hence, DPP-4 inhibitors were developed, as well as several GLP-1 analogs engineered to circumvent DPP-4-mediated breakdown and/or rapid renal elimination. Three categories of GLP-1 analogs, are being developed and/or are in clinical use: short-acting, long-acting, and prolonged-acting GLP-1 analogs. Each class has different plasma half-lives, molecular size, and homology to native GLP-1, and consequently different characteristic effects on glucose metabolism. In this article, we review current clinical data derived from each class of GLP-1 analogs, and consider the clinical effects reported for each category in recent head to head comparison studies. Given the relatively brief clinical history of these compounds, we also highlight several important efficacy and safety issues which will require further investigation.
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Hyperthyroidism is one of the causes of thyrotoxicosis and the most common cause of hyperthyroidism in Korea is Graves disease. The diagnosis and treatment of Graves disease are different according to geographical area. Recently, the American Thyroid Association and the American Association of Clinical Endocrinologists suggested new management guidelines for hyperthyroidism. However, these guidelines are different from clinical practice in Korea and are difficult to apply. Therefore, the Korean Thyroid Association (KTA) conducted a survey of KTA members regarding the diagnosis and treatment of hyperthyroidism, and reported the consensus on the management of hyperthyroidism. In this review, we summarized the KTA report on the contemporary practice patterns in the diagnosis and management of hyperthyroidism, and compared this report with guidelines from other countries.
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Adipocyte-specific fatty acid-binding protein (A-FABP) is a cytoplasmic protein expressed in macrophages and adipocytes and it plays a role in insulin resistance and metabolic syndrome. Recently, the fatty liver index (FLI) was introduced as an indicator of nonalcoholic fatty liver disease (NAFLD). In this study, we aimed to investigate the relationship between baseline serum A-FABP levels and FLI after 4 years in apparently healthy subjects.
A total of 238 subjects without a past history of alcoholism or hepatitis were recruited from a medical check-up program. The NAFLD state was evaluated 4 years later in the same subjects using FLI. Fatty liver disease was diagnosed as diffusely increased echogenicity of the hepatic parenchyma compared to the kidneys, vascular blurring, and deep-echo attenuation. NAFLD was defined as subjects with fatty liver and no history of alcohol consumption (>20 g/day).
Baseline serum A-FABP levels were significantly associated with FLI after adjustment for age and sex (
This study demonstrated that higher baseline serum A-FABP levels were associated with FLI as a predictive indicator of NAFLD after 4 years of follow-up in healthy Korean adults.
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Stress affects body weight and food intake, but the underlying mechanisms are not well understood.
We evaluated the changes in body weight and food intake of ICR male mice subjected to daily 2 hours restraint stress for 15 days. Hypothalamic gene expression profiling was analyzed by cDNA microarray.
Daily body weight and food intake measurements revealed that both parameters decreased rapidly after initiating daily restraint stress. Body weights of stressed mice then remained significantly lower than the control body weights, even though food intake slowly recovered to 90% of the control intake at the end of the experiment. cDNA microarray analysis revealed that chronic restraint stress affects the expression of hypothalamic genes possibly related to body weight control. Since decreases of daily food intake and body weight were remarkable in days 1 to 4 of restraint, we examined the expression of food intake-related genes in the hypothalamus. During these periods, the expressions of ghrelin and pro-opiomelanocortin mRNA were significantly changed in mice undergoing restraint stress. Moreover, daily serum corticosterone levels gradually increased, while leptin levels significantly decreased.
The present study demonstrates that restraint stress affects body weight and food intake by initially modifying canonical food intake-related genes and then later modifying other genes involved in energy metabolism. These genetic changes appear to be mediated, at least in part, by corticosterone.
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Therapeutic Effects of Modified Gengnianchun Formula on Stress-Induced Diminished Ovarian Reserve Based on Experimental Approaches and Network Pharmacology
Enhanced lipogenesis plays a critical role in cell senescence via induction of expression of the mature form of sterol regulatory element binding protein 1 (SREBP1), which contributes to an increase in organellar mass, one of the indicators of senescence. We investigated the molecular mechanisms by which signaling molecules control SREBP1-mediated lipogenesis and senescence.
We developed cellular models for stress-induced senescence, by exposing Chang cells, which are immortalized human liver cells, to subcytotoxic concentrations (200 µM) of deferoxamine (DFO) and H2O2.
In this model of stress-induced cell senescence using DFO and H2O2, the phosphorylation profile of glycogen synthase kinase 3α (GSK3α) and β corresponded closely to the expression profile of the mature form of SREBP-1 protein. Inhibition of GSK3 with a subcytotoxic concentration of the selective GSK3 inhibitor SB415286 significantly increased mature SREBP1 expression, as well as lipogenesis and organellar mass. In addition, GSK3 inhibition was sufficient to induce senescence in Chang cells. Suppression of GSK3 expression with siRNAs specific to GSK3α and β also increased mature SREBP1 expression and induced senescence. Finally, blocking lipogenesis with fatty acid synthase inhibitors (cerulenin and C75) and siRNA-mediated silencing of SREBP1 and ATP citrate lyase (ACL) significantly attenuated GSK3 inhibition-induced senescence.
GSK3 inactivation is an important upstream event that induces SREBP1-mediated lipogenesis and consequent cell senescence.
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It is not clear whether microangiopathies are associated with subclinical atherosclerosis in type 2 diabetes mellitus (T2DM). We investigated the relation of cardiac autonomic neuropathy (CAN) and other microangiopathies with carotid atherosclerosis in T2DM.
A total of 131 patients with T2DM were stratified by mean carotid intima-media thickness (CIMT) ≥ or <1.0 mm and the number of carotid plaques. CAN was assessed by the five standard cardiovascular reflex tests according to the Ewing's protocol. CAN was defined as the presence of at least two abnormal tests or an autonomic neuropathy points ≥2. Diabetic microangiopathies were assessed.
Patients with CAN comprised 77% of the group with mean CIMT ≥1.0 mm, while they were 29% of the group with CIMT <1.0 mm (
These results suggest that CAN is associated with carotid atherosclerosis, represented as CIMT and plaques, independent of the traditional cardiovascular risk factors in T2DM. CAN or DR may be a determinant of subclinical atherosclerosis in T2DM.
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Von Hippel-Lindau (VHL) disease is an autosomal dominantly inherited, multisystemic tumor syndrome caused by mutations in the
A 30-year-old woman presented with gestational diabetes mellitus. She sequentially showed multiple pancreatic cysts, spinal cord hemangioblastoma, cerebellar hemangioblastoma, and clear cell type renal cell carcinomas. Also, her father and brother had brain hemangioblastomas. Each of the three exons of the
DNA sequence analysis to determine the presence of
We found a novel mutation in the
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Insulin autoimmune syndrome (IAS) is characterized by spontaneous hypoglycemia caused by insulin autoantibodies in the absence of exogenous insulin administration. Some drugs containing sulfhydryl compounds are known to initiate the onset of IAS. A 67-year-old female who had diabetes for 5 years visited the outpatient clinic at our institution due to diabetic peripheral polyneuropathy. She was prescribed α-lipoic acid (ALA), which contains two sulfur atoms. Two weeks later, she complained of recurrent hypoglycemic symptoms. We detected a high level of insulin and high titers of insulin autoantibodies. Her human leukocyte antigen (HLA) genotype included the DRB1*0406 allele, which indicates a high level of susceptibility to IAS. She was treated with prednisolone. After this episode, she experienced two more hypoglycemic events after taking ALA for diabetic neuropathy in other hospitals. As ALA can be used to treat diabetic peripheral polyneuropathy, physician discretion is advised based on the possibility of IAS due to ALA in diabetic patients.
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Rhabdomyolysis is a syndrome involving the breakdown of skeletal muscle that causes myoglobin and other intracellular proteins to leak into the circulatory system, resulting in organ injury including acute kidney injury. We report a case of statin-induced rhabdomyolysis and acute kidney injury that developed in a 63-year-old woman with previously undiagnosed hypothyroidism. Untreated hypothyroidism may have caused her hypercholesterolemia requiring statin treatment, and it is postulated that statin-induced muscle injury was aggravated by hypothyroidism resulting in her full-blown rhabdomyolysis. Although this patient was successfully treated with continuous venovenous hemofiltration and L-thyroxin replacement, rhabdomyolysis with acute kidney injury is a potentially life-threatening disorder. Physicians must pay special attention to the possible presence of subclinical hypothyroidism when administering statins in patients with hypercholesterolemia.
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Due to the increased prevalence of papillary thyroid carcinoma (PTC), difficult cases and unexpected events have become more common during long-term follow-up. Herein we reported four cases that exhibited poor progress during long-term follow-up. All the cases were diagnosed with PTC and treated with total thyroidectomy before several years, and the patients had been newly diagnosed with recurrent and metastatic PTC. These four cases included recurred PTC with invasion of large blood vessels, a concomitant second malignancy, malignant transformation, and refractoriness to treatment. Physicians should closely monitor patients to promptly address unforeseen circumstances during PTC follow-up, including PTC recurrence and metastasis. Furthermore, we suggest that the development of a management protocol for refractory or terminal PTC is also warranted.
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Papillary thyroid carcinoma (PTC) is a common affliction of the thyroid gland, accounting for 70% to 80% of all thyroid cancers, whereas mucosa-associated lymphoid tissue (MALT) lymphoma of the thyroid gland is uncommon. The simultaneous occurrence of both malignancies is extremely rare. We report the case of a patient with both PTC and MALT lymphoma in the setting of Hashimoto thyroiditis. An 81-year-old female patient was first admitted with goiter and hoarseness, which was attributed to an ultrasonographic thyroid nodule. Subsequent fine-needle aspirate, interpreted as suspicious of papillary thyroid cancer, prompted total thyroidectomy. MALT lymphoma was an incidental postsurgical finding, coexisting with PTC in the setting of Hashimoto thyroiditis. Although the development of MALT lymphoma is very rare, patients with longstanding Hashimoto thyroiditis should undergo careful surveillance for both malignancies.
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