Association of Blood Pressure With Cardio-Renal Events and Mortality in Type 2 DM: A National Health Insurance Database.

CONTEXT: The relationship of blood pressure (BP) with cardio-renal events and all-cause mortality in type 2 diabetes mellitus (T2DM) is still controversial. OBJECTIVE: To investigate the optimal BP target in Korean individuals with T2DM. METHODS: Using the Korean National Health Insurance System database, data of individuals with T2DM who underwent regular health checks from January 1, 2007, to December 31, 2007, were extracted (N = 1 800 073). Among them, a total of 326 593 individuals were included in the final study. The study population was divided into 7 groups according to their observed systolic blood pressure (SBP) (<110, 110-119, 120-129, 130-139, 140-149, 150-159, 160-169, and ≥170 mmHg) and diastolic blood pressure (DBP) (<65, 65-69, 70-74, 75-79, 80-84, 85-89, and ≥90 mmHg). Hazard ratios (HRs) of cardio-renal events and all-cause mortality according to BP categories were analyzed. RESULTS: Compared with SBP of 120-129 mmHg and DBP of 75-79 mmHg, SBP of ≥130 mmHg and DBP of ≥ 80 mmHg were associated with an increase in HR of major cardiovascular adverse events (MACEs). SBP of 120-129 mmHg and DBP 75-79 mmHg were associated with the lowest HR of all-cause mortality. Both lower BP (SBP/DBP <120/70 mm) and higher BP (SBP/DBP ≥130/80 mmHg) were associated with an increased HR of all-cause mortality. Contrary to MACE, the lower the SBP, the lower the HR of renal events. CONCLUSION: In patients with T2DM, the optimal cutoff value of BP associated with a lower incidence of MACE and mortality may be 120-129 mmHg for SBP and 75-79 mmHg for DBP. However, lower SBP may be helpful for T2DM patients with a high risk of renal disease.

In-depth proteomic signature of parathyroid carcinoma.

OBJECTIVE: Diagnosing parathyroid carcinoma (PC) is complicated and controversial that early diagnosis and intervention are often difficult. Therefore, we aimed to elucidate the protein signatures of PC through quantitative proteomic analyses to aid in the early and accurate diagnosis of PC. DESIGN: We conducted a retrospective cohort study. METHODS: We performed liquid chromatography with tandem mass spectrometry using formalin-fixed paraffin-embedded samples. For the analyses, 23 PC and 15 parathyroid adenoma (PA) tissues were collected from 6 tertiary hospitals in South Korea. RESULTS: The mean age of the patients was 52 years, and 63% were women. Proteomic expression profiling revealed 304 differentially expressed proteins (DEPs) with a cut-off of P < .05 and fold change >1.5. Among DEPs, we identified a set of 5 proteins that can discriminate PC from PA: carbonic anhydrase 4 (CA4), alpha/beta hydrolase domain-containing protein 14B (ABHD14B), laminin subunit beta-2 (LAMB2), CD44 antigen (CD44), and alpha-1-acid glycoprotein 1 (ORM1) that exhibited the highest area under the curve of 0.991 in neural network model. The nuclear percentage of CA4 and LAMB2 in immunohistochemistry was significantly lower in PC tissue than in the PA (CA4: 2.77 ± 1.96%, 26.2 ± 3.45%, P < .001; LAMB2: 6.86 ± 3.46%, 38.54 ± 4.13%, P < .001). The most enriched canonical pathways in PC included glycoprotein-6 signaling and mammalian target of rapamycin (mTOR). CONCLUSIONS: We identified key proteins differentially expressed between PC and PA using proteomic analyses of parathyroid neoplasms. These findings may help to diagnose PC accurately and elucidate potential therapeutic targets.

The parathyroid glands and parathyroid hormone: Insights from PTH gene mutations.

Nine mutations have been discovered in the parathyroid hormone (PTH) gene since it was initially sequenced in 1983. An autosomal dominant C18R mutation in the signal peptide was first reported in 1990, followed by an exon skipping mutation, leading to loss of exon 2 in 1992; the latter mutation prevents PTH biosynthesis, as exon 2 contains the initiation codon. The S23P and S23X mutations affecting the same residue were reported in 1999 and 2012, respectively, while in 2008, the somatic mutation, R83X, was detected in a parathyroid adenoma tissue sample from a patient with overt hyperparathyroidism. In 2013, the heterozygous p.Met1_Asp6del mutation was discovered incidentally in a case-control study, while another heterozygous mutation, M14K, was detected in the signal peptide 4 years later. In 2015, a homozygous R56C mutation was reported, and was the first hypoparathyroidism-causing mutation identified that affects the mature bioactive portion of PTH; this mutation has significantly contributed to the understanding of the molecular mechanisms involved in signal transduction through the PTH receptor. Recently, a novel homozygous S32P mutation was identified, which is also situated in the bioactive portion of PTH. The discovery of these nine mutations in the PTH gene and determination of the molecular mechanisms underlying their effects has provided deep insights into the synthesis, processing, and secretion of PTH. Future attempts to discover other such mutations will help elucidate as yet unknown functions of PTH, with potential clinical implications.

Metabolic Subtyping of Adrenal Tumors: Prospective Multi-Center Cohort Study in Korea.

BACKGROUND: Conventional diagnostic approaches for adrenal tumors require multi-step processes, including imaging studies and dynamic hormone tests. Therefore, this study aimed to discriminate adrenal tumors from a single blood sample based on the combination of liquid chromatography-mass spectrometry (LC-MS) and machine learning algorithms in serum profiling of adrenal steroids. METHODS: The LC-MS-based steroid profiling was applied to serum samples obtained from patients with nonfunctioning adenoma (NFA, n=73), Cushing's syndrome (CS, n=30), and primary aldosteronism (PA, n=40) in a prospective multicenter study of adrenal disease. The decision tree (DT), random forest (RF), and extreme gradient boost (XGBoost) were performed to categorize the subtypes of adrenal tumors. RESULTS: The CS group showed higher serum levels of 11-deoxycortisol than the NFA group, and increased levels of tetrahydrocortisone (THE), 20α-dihydrocortisol, and 6ß-hydroxycortisol were found in the PA group. However, the CS group showed lower levels of dehydroepiandrosterone (DHEA) and its sulfate derivative (DHEA-S) than both the NFA and PA groups. Patients with PA expressed higher serum 18-hydroxycortisol and DHEA but lower THE than NFA patients. The balanced accuracies of DT, RF, and XGBoost for classifying each type were 78%, 96%, and 97%, respectively. In receiver operating characteristics (ROC) analysis for CS, XGBoost, and RF showed a significantly greater diagnostic power than the DT. However, in ROC analysis for PA, only RF exhibited better diagnostic performance than DT. CONCLUSION: The combination of LC-MS-based steroid profiling with machine learning algorithms could be a promising one-step diagnostic approach for the classification of adrenal tumor subtypes.

Inherited Disorders of Thyroid Hormone Metabolism Defect Caused by the Dysregulation of Selenoprotein Expression.

Consistent activation and functioning of thyroid hormones are essential to the human body as a whole, especially in controlling the metabolic rate of all organs and systems. Impaired sensitivity to thyroid hormones describes any process that interferes with the effectiveness of thyroid hormones. The genetic origin of inherited thyroid hormone defects and the investigation of genetic defects upon the processing of thyroid hormones are of utmost importance. Impaired sensitivity to thyroid hormone can be categorized into three conditions: thyroid hormone cell membrane transport defect (THCMTD), thyroid hormone metabolism defect (THMD), and thyroid hormone action defect (THAD). THMD is caused by defects in the synthesis and processing of deiodinases that convert the prohormone thyroxine (T4) to the active hormone triiodothyronine (T3). Deiodinase, a selenoprotein, requires unique translation machinery that is collectively composed of the selenocysteine (Sec) insertion sequence (SECIS) elements, Sec-insertion sequence-binding protein 2 (SECISBP2), Sec-specific eukaryotic elongation factor (EEFSEC), and Sec-specific tRNA (TRU-TCA1-1), which leads to the recognition of the UGA codon as a Sec codon for translation into the growing polypeptide. In addition, THMD could be expanded to the defects of enzymes that are involved in thyroid hormone conjugation, such as glucuronidation and sulphation. Paucity of inherited disorders in this category leaves them beyond the scope of this review. This review attempts to specifically explore the genomic causes and effects that result in a significant deficiency of T3 hormones due to inadequate function of deiodinases. Moreover, along with SECISBP2, TRU-TCA1-1, and deiodinase type-1 (DIO1) mutations, this review describes the variants in DIO2 single nucleotide polymorphism (SNP) and thyroid stimulating hormone receptor (TSHR) that result in the reduced activity of DIO2 and subsequent abnormal conversion of T3 from T4. Finally, this review provides additional insight into the general functionality of selenium supplementation and T3/T4 combination treatment in patients with hypothyroidism, suggesting the steps that need to be taken in the future.

Rare PTH Gene Mutations Causing Parathyroid Disorders: A Review.

Since parathyroid hormone (PTH) was first isolated and its gene (PTH) was sequenced, only eight PTH mutations have been discovered. The C18R mutation in PTH, discovered in 1990, was the first to be reported. This autosomal dominant mutation induces endoplasmic reticulum stress and subsequent apoptosis in parathyroid cells. The next mutation, which was reported in 1992, is associated with exon skipping. The substitution of G with C in the first nucleotide of the second intron results in the exclusion of the second exon; since this exon includes the initiation codon, translation initiation is prevented. An S23P mutation and an S23X mutation at the same residue were reported in 1999 and 2012, respectively. Both mutations resulted in hypoparathyroidism. In 2008, a somatic R83X mutation was detected in a parathyroid adenoma tissue sample collected from a patient with hyperparathyroidism. In 2013, a heterozygous p.Met1_Asp6del mutation was incidentally discovered in a case-control study. Two years later, the R56C mutation was reported; this is the only reported hypoparathyroidism-causing mutation in the mature bioactive part of PTH. In 2017, another heterozygous mutation, M14K, was detected. The discovery of these eight mutations in the PTH gene has provided insights into its function and broadened our understanding of the molecular mechanisms underlying mutation progression. Further attempts to detect other such mutations will help elucidate the functions of PTH in a more sophisticated manner.

Ca2+ allostery in PTH-receptor signaling.

The parathyroid hormone (PTH) and its related peptide (PTHrP) activate PTH receptor (PTHR) signaling, but only the PTH sustains GS-mediated adenosine 3',5'-cyclic monophosphate (cAMP) production after PTHR internalization into early endosomes. The mechanism of this unexpected behavior for a G-protein-coupled receptor is not fully understood. Here, we show that extracellular Ca2+ acts as a positive allosteric modulator of PTHR signaling that regulates sustained cAMP production. Equilibrium and kinetic studies of ligand-binding and receptor activation reveal that Ca2+ prolongs the residence time of ligands on the receptor, thus, increasing both the duration of the receptor activation and the cAMP signaling. We further find that Ca2+ allostery in the PTHR is strongly affected by the point mutation recently identified in the PTH (PTHR25C) as a new cause of hypocalcemia in humans. Using high-resolution and mass accuracy mass spectrometry approaches, we identified acidic clusters in the receptor's first extracellular loop as key determinants for Ca2+ allosterism and endosomal cAMP signaling. These findings coupled to defective Ca2+ allostery and cAMP signaling in the PTHR by hypocalcemia-causing PTHR25C suggest that Ca2+ allostery in PTHR signaling may be involved in primary signaling processes regulating calcium homeostasis.

Concurrent TSHR mutations and DIO2 T92A polymorphism result in abnormal thyroid hormone metabolism.

Deiodinase 2 (DIO2) plays an important role in thyroid hormone metabolism and its regulation. However, molecular mechanism that regulates DIO2 activity remains unclear; only mutaions in selenocysteine insertion sequence binding protein 2 and selenocysteine tranfer RNA (tRNA[Ser]Sec) are reported to result in decreased DIO2 activity. Two patients with clinical evidence of abnormal thyroid hormone metabolism were identified and found to have TSHR mutations as well as DIO2 T92A single nucleotide polymorphism (SNP). Primary-cultured fibroblasts from one patient present a high level of basal DIO2 enzymatic activity, possibly due to compensation by augmented DIO2 expression. However, this high enzymatic active state yet fails to respond to accelerating TSH. Consequently, TSHR mutations along with DIO2 T92A SNP ("double hit") may lead to a significant reduction in DIO2 activity stimulated by TSH, and thereby may have clinical relevance in a select population of hypothyroidism patients who might benefit from a T3/T4 combination therapy.

Free triiodothyronine/free thyroxine ratio rather than thyrotropin is more associated with metabolic parameters in healthy euthyroid adult subjects.

OBJECTIVE: The interrelation between TSH, thyroid hormones and metabolic parameters is complex and has not been confirmed. This study aimed to determine the association of TSH and thyroid hormones in euthyroid subjects and the relationship between thyroid function and metabolic risk factors. Furthermore, this study examined whether thyroid function has predictive power for metabolic syndrome. DESIGN: This is a cross-sectional study that included subjects in a medical health check-up programme at a single institution. PATIENTS: The study included 132 346 participants (66 991 men and 65 355 women) aged over 18 years who had TSH, free T4 (FT4) and free T3 (FT3) levels within the institutional reference ranges. MEASUREMENTS: Thyrotropin, FT4, FT3 and metabolic parameters including height, weight, waist circumference, blood pressure, serum levels of total cholesterol, triglyceride, high-density lipoprotein cholesterol, insulin and glucose were measured. RESULTS: There was a positive association between FT3/FT4 ratio and TSH in both men and women after adjusting for age, body mass index, smoking status and menopausal status (in women). The FT3/FT4 ratio and TSH were positively associated with risk of metabolic syndrome parameters including insulin resistance. The FT3/FT4 ratio had a greater predictive power than TSH for metabolic syndrome in both men and women. CONCLUSIONS: Thyrotropin levels were positively associated with FT3/FT4 ratio within the euthyroid range. The higher FT3/FT4 ratio is associated with increased risk of metabolic syndrome parameters and insulin resistance. FT3/FT4 ratio has a better predictive power for metabolic syndrome than TSH.

Identification of the Mutations in the Prostaglandin Transporter Gene, SLCO2A1 and Clinical Characterization in Korean Patients with Pachydermoperiostosis.

Pachydermoperiostosis (PDP), or primary hypertrophic osteoarthropathy, is a rare genetic disease affecting both skin and bones. Both autosomal dominant with incomplete penetrance and recessive inheritance of PDP have been previously confirmed. Recently, hydroxyprostaglandin dehydrogenase (HPGD) and solute carrier organic anion transporter family member 2A1 (SLCO2A1) were reported as pathogenic genes responsible for PDP. Both genes are involved in prostaglandin E2 (PGE2) degradation. We aimed to identify responsible genes for PDP and the clinical features in Korean patients with PDP. Six affected individuals and their available healthy family members from three unrelated Korean families with PDP were studied. All of the patients displayed complete phenotypes of PDP with finger clubbing, pachydermia, and periostosis. Mutation analysis revealed a novel heterozygous mutation in the SLCO2A1 gene at nucleotide 302 causing a substitution of the amino acid isoleucine to serine at codon 101 (p.IIe101Ser) in affected individuals. We also identified known SLCO2A1 mutations, one homozygous for c.940+1G>A, and another compound heterozygous for c.940+1G>A and c.1807C>T (p.Arg603*) from two PDP families. Genetic analyses of the PDP patients showed no abnormality in the HPGD gene. Our study further supports the role of mutations in the SLCO2A1 gene in the pathogenesis of PDP and could provide additional clues to the genotype-phenotype relations of PDP.

A Homozygous [Cys25]PTH(1-84) Mutation That Impairs PTH/PTHrP Receptor Activation Defines a Novel Form of Hypoparathyroidism.

Hypocalcemia and hyperphosphatemia are encountered in idiopathic hypoparathyroidism (IHP) and pseudohypoparathyroidism type Ib (PHP1B). In contrast to PHP1B, which is caused by resistance toward parathyroid hormone (PTH), the genetic defects leading to IHP impair production of this important regulator of mineral ion homeostasis. So far, only five PTH mutations were shown to cause IHP, each of which is located in the hormone's pre-pro leader segment and thus impair hormone secretion. In three siblings affected by IHP, we now identified a homozygous arginine-to-cysteine mutation at position 25 (R25C) of the mature PTH(1-84) polypeptide; heterozygous family members are healthy. Depending on the assay used for evaluating these patients, plasma PTH levels were either low or profoundly elevated, thus leading to ambiguities regarding the underlying diagnosis, namely IHP or PHP1B. Consistent with increased PTH levels, recombinant [Cys25]PTH(1-84) and wild-type PTH(1-84) were secreted equally well by transfected COS-7 cells. However, synthetic [Cys25]PTH(1-34) was found to have a lower binding affinity for the PTH receptor type-1 (PTH1R) than PTH(1-34) and consequently a lower efficiency for stimulating cAMP formation in cells expressing this receptor. Consistent with these in vitro findings, long-term infusion of [Cys25]PTH(1-34) resulted only in minimal calcemic and phosphaturic responses, despite readily detectable levels of [Cys25]PTH(1-34) in plasma. The mineral ion abnormalities observed in the three IHP patients are thus most likely caused by the inherited homozygous missense PTH mutation, which reduces bioactivity of the secreted hormone. Based on these findings, screening for PTH(1-84) mutations should be considered when clinical and laboratory findings are consistent with PHP1B, but GNAS methylation changes have been excluded. Differentiating between IHP and PHP1B has considerable implications for genetic counseling, therapy, and long-term outcome because treatment of IHP patients with inappropriately high doses of active vitamin D and calcium can contribute to development of nephrocalcinosis and chronic kidney disease.

The role of insulin resistance and metabolic risk factors on culprit coronary plaque.

BACKGROUND: Detailed relationships between insulin resistance (IR) and vulnerable plaque are not clear, therefore, we sought the role of IR and metabolic risk factors on culprit coronary plaque. METHODS: Plaque components at a region of interest (ROI, 10mm) were analyzed by virtual histology intravascular ultrasound. IR was defined as quantitative insulin sensitivity check index (QUICKI) ≤ 0.33. Seven metabolic risk factors (5 risk factors for metabolic syndrome defined by ATP III, history of smoking, and hsCRP) for IR were determined. RESULTS: The data for 150 (males 104) patients were analyzed. Patients with IR (n = 69) had greater necrotic core (NC) at the ROI (21.2 ± 15.8mm(3) vs 15.7 ± 11.9 mm(3), p = 0.02) than in patients without IR (n = 81). The NC at the ROI was correlated with QUICKI (r = -0.16, p = 0.05), HbA1c (r = 0.24, p < 0.01), body mass index (r = 0.17, p = 0.04), presence of diabetes mellitus (r = 0.29, p < 0.001), hsCRP (r = 0.17, p = 0.04) and the numbers of risk factors for IR (r = 0.41, p < 0.001). The multivariate analysis revealed that the numbers of risk factors for IR was an independent factor for the NC at the ROI (beta coefficient = 0.44, p = 0.003), but QUICKI was not (beta coefficient = -0.01, p = 0.94). CONCLUSIONS: Instead of a single measurement of IR index or each metabolic risk factor, clustering of risk factors for IR plays an important role on plaque vulnerability. CONDENSED ABSTRACT: We investigated the role of insulin resistance (IR) on culprit coronary plaque. Patients with IR had a greater amount of necrotic core in culprit coronary lesions than in patients without IR. Rather than a single measurement of IR index or each metabolic risk factor, clustering of metabolic risk factors for IR plays an important role in plaque vulnerability in patients with coronary artery disease. Our study demonstrates the role of IR on culprit coronary plaque and highlights the importance of the clustering of metabolic risk factors for IR in vulnerable plaque pathogenesis.

Genetic Analysis of Multiple Endocrine Neoplasia Type 1 (MEN1) Leads to Misdiagnosis of an Extremely Rare Presentation of Intrasellar Cavernous Hemangioma as MEN1.

BACKGROUND: Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited disorder characterized by the simultaneous occurrence of endocrine tumors in target tissues (mainly the pituitary, endocrine pancreas, and parathyroid glands). MEN1 is caused by mutations in the MEN1 gene, which functions as a tumor suppressor and consists of one untranslated exon and nine exons encoding the menin protein. This condition is usually suspected when we encounter patients diagnosed with tumors in multiple endocrine organs, as mentioned above. METHODS: A 65-year-old woman who underwent surgery for a pancreatic tumor (serous cystadenoma) 5 years previously was referred to our hospital due to neurologic symptoms of diplopia and left ptosis. Brain magnetic resonance imaging revealed a 3.4-cm lesion originating from the cavernous sinus wall and extending into the sellar region. It was thought to be a nonfunctioning tumor from the results of the combined pituitary function test. Incidentally, we found that she also had a pancreatic tumor, indicating the necessity of genetic analysis for MEN1. RESULTS: Genomic analysis using peripheral leukocytes revealed a heterozygous c.1621G>A mutation in the MEN1 gene that was previously reported to be either a pathogenic mutation or a simple polymorphism. We pursued a stereotactic approach to the pituitary lesion, and microscopic findings of the tumor revealed it to be an intrasellar cavernous hemangioma, a rare finding in the sellar region and even rarer in relation to oculomotor palsy. The patient recovered well from surgery, but refused further evaluation for the pancreatic lesion. CONCLUSION: There is great emphasis placed on genetic testing in the diagnosis of MEN1, but herein we report a case where it did not assist in diagnosis, hence, further discussion on the role of genetic testing in this disease is needed. Also, in cases of pituitary tumor with cranial nerve palsy, despite its low prevalence, intrasellar cavernous hemangioma could be suspected.

Postoperative Cervical Cord Compression Induced by Hydrogel Dural Sealant (DuraSeal®).

Cerebrospinal fluid (CSF) leakage is a potential complication of cranial and spinal surgery. Postoperative CSF leakage can induce delayed healing, wound infection and meningitis. DuraSeal® (Covidien, Waltham, MA, USA) is a synthetic product which has been increasingly used to facilitate watertight repair of dural defects after cranial and spinal surgery. Despite some advantages of Duraseal®, the authors report a patient who developed cord compression following the use of DuraSeal® in cervical spine surgery in which the expansion of the DuraSeal® was believed to be the causative factor.

Association between brachial-ankle pulse wave velocity and occult coronary artery disease detected by multi-detector computed tomography.

BACKGROUND: Arterial stiffness, assessed by aortic pulse wave velocity (PWV), has been reported to predict cardiovascular morbidity and mortality. We assessed the association between arterial stiffness, as determined by PWV, and occult coronary artery disease (CAD), as detected by multi-detector computed tomography (MDCT), in asymptomatic individuals. METHOD: We retrospectively enrolled 615 consecutive South Korean individuals who had undergone both brachial-ankle PWV (baPWV) and coronary CT angiography during general routine health evaluations at the Asan Medical Center in 2008. RESULTS: We found that baPWV was positively correlated with age; body mass index; blood pressure; total cholesterol, homocysteine, and fasting blood glucose concentrations; and coronary artery calcium score. When we divided subjects into two groups according to the results of MDCT, we found that baPWV was significantly higher in subjects with (diameter of stenosis >50%) than without CAD (1573.2 ± 275.6 cm/s vs. 1409.6 ± 235.6 cm/s, p<0.01). The optimal baPWV cutoff value for detection of significant coronary arterial stenosis was 1426.0 cm/s, which had a sensitivity of 77% and a specificity of 63% (area under curve=0.71). After adjusting for age, smoking status, hypertension, diabetes, and dyslipidemia, the odds ratio for significant occult CAD was 3.30 (95% CI=1.47-7.41, p<0.01). CONCLUSION: We found that baPWV was associated with risk factors for cardiovascular disease, including CACS, in asymptomatic individuals, and the optimal baPWV cutoff value for occult CAD detected by MDCT was 1426 cm/s. These findings suggest that baPWV may be a useful screening tool for predicting occult CAD.

Identification and characterization of C106R, a novel mutation in the DNA-binding domain of GCMB, in a family with autosomal-dominant hypoparathyroidism.

OVERVIEW: Glial cells missing B (GCMB) is a transcription factor that is expressed in the parathyroid hormone (PTH)-secreting cells of the parathyroid glands. Several mutations in GCMB have been reported to cause hypoparathyroidism (HP). We identified a family with two individuals in two generations (mother and son), who are affected by autosomal-dominant hypoparathyroidism (AD-HP). A novel heterozygous mutation in exon 2 of GCMB was identified in both affected individuals that changes cysteine at position 106 of the putative DNA-binding domain of GCMB to arginine (C106R). METHODS: We performed mutational analysis of the genes encoding GCMB, pre-pro PTH, GATA3 and CaSR using polymerase chain reaction (PCR)-amplified genomic DNA. The identified GCMB mutant was characterized by functional studies including nuclear localization, electrophoretic mobility shift assays (EMSA) and luciferase reporter assays, and homology modelling was performed to generate a three-dimensional structural model for the DNA-binding domain of GCMB to predict the structural consequences of the identified mutation. RESULTS: The C106R mutant of GCMB failed to interact with the DNA consensus recognition motif, as determined by EMSA. Furthermore, in comparison with wild-type GCMB, the C106R mutant demonstrated reduced transactivation in luciferase reporter assays; however, the mutant GCMB failed to reduce the activity of the wild-type protein. Consistent with the EMSA findings, homology modelling analysis suggested that replacement of cysteine 106 with arginine would interfere with DNA binding. CONCLUSIONS: We have identified a novel GCMB mutation that may explain AD-HP in our family. However, the exact mechanism by which this heterozygous mutation leads to the disease in the described family remains to be elucidated.

Angiogenesis inhibitor attenuates parathyroid hormone-induced anabolic effect.

In vivo osteogenic responses to anabolic stimuli are expected to be accompanied by angiogenesis as well as in the process of remodeling of bone. Consequently, angiogenesis might play an important role in mediating bone forming stimulating effect of parathyroid hormone (PTH). To investigate this relationship, we used actively growing young Sprague-Dawley rats and CKD-732, one of the angiogenesis inhibitor (AI) to reveal the relationship of angiogenesis in the effect of PTH. The groups were divided as (1) vehicle [VEH group], (2) PTH(1-84) [PTH group], (3) AI alone [AI group], (4) PTH(1-84)+AI concomitance [PTH-AI group] and were treated for 6 weeks. The bone mineral density (BMD) of PTH group was higher than VEH group and the gain of bone mass was attenuated in PTH-AI group. The maximal failure load in PTH group was higher than VEH group, but it was definitely attenuated by concurrent use of AI. Moreover, the toughness showed similar significant deterioration in PTH-AI group. General bone turnover was also significantly decreased in PTH-AI group as shown by the absence of increase in osteocalcin and beta-crosslaps and by decrease in metaphyseal length. The BMD or the biomechanic data of AI only group were similar to the VEH group, suggesting the minimal effect of AI itself on the normal modeling phase of the growing rats. In conclusion, the angiogenesis seemed to contribute to completing the anabolic effect of PTH especially for bone strength.