Fracture recurrence in hip fracture with menopausal hormone therapy versus risedronate: a clinical trial.

OBJECTIVES: An open-label, randomized trial was conducted to examine the effects of risedronate versus menopausal hormone therapy (MHT) in postmenopausal women with recent hip fracture. METHODS: Among 1165 eligible women, 281 were recruited and randomly assigned to receive oral risedronate (35 mg/week) or percutaneous estradiol gel (1.5 mg/day) plus oral micronized progesterone (100 mg/day) for 4 years. The primary end point was recurrent fracture and the secondary end points were mortality and bone mineral density (BMD). RESULTS: Kaplan-Meier analyses showed no significant differences in fracture recurrence and mortality between the two groups. The incidence of any new fracture per 100 person-years (PY) was 8.63 in the risedronate group and 12.86 in the MHT group (p = 0.180); that of clinical fracture was 4.75 and 6.99, respectively (p = 0.265); and that of asymptomatic vertebral fracture was 4.87 and 5.58, respectively (p = 0.764). The respective incidence of death per 100 PY was 3.58 and 4.40 (p = 0.503). BMD increased comparably at the lumbar spine in both groups. BMD at the total hip did not change in the risedronate group, but increased significantly by 2.8% in the MHT group. CONCLUSIONS: MHT might not differ from risedronate in the prevention of secondary fractures and death among postmenopausal women with recent hip fracture.

Influence of gastrointestinal events on treatment of osteoporosis in Asia-Pacific women: Perspectives from physicians in the MUSIC OS-AP study.

BACKGROUND: The objectives of the physician survey component of the MUSIC OS-AP study were to describe physicians' approaches to treatment of women with postmenopausal osteoporosis and to understand the influence of gastrointestinal (GI) events on treatment in clinical practice. METHODS: Physicians were recruited from 5 Asia-Pacific countries. Questionnaires collected information about physicians' standard practices for treatment of patients with osteoporosis, as well as their perspectives on the influence of GI events on osteoporosis treatment approaches. RESULTS: A total of 59 physicians participated in the study. The most frequently prescribed or recommended treatments were vitamin D (84% of patients), calcium (82%), and oral bisphosphonates (59%). When choosing a medication for treatment-naïve patients, GI sensitivity was often or always a factor for 79% of physicians. Among physicians not prescribing pharmacologic treatment, a mean of 18% of non-prescriptions were due to GI sensitivity. For patients with pre-existing GI conditions, physicians most frequently ranked use of non-oral osteoporosis medication as the first treatment strategy (47%), followed by co-prescription with a proton pump inhibitor or other gastro-protective agent (31%). For patients developing GI symptoms after starting pharmacologic treatment, the most frequently first-ranked management strategy was to check if patients were taking their osteoporosis medication correctly as prescribed (64%), followed by temporary discontinuation of the medication (i.e., a drug holiday) until GI events have resolved (31%) and co-prescription with a proton pump inhibitor or other gastroprotective agent (24%). CONCLUSIONS: These results suggest that GI events influence the prescribing practices of physicians in the Asia-Pacific region and sometimes result in non-treatment of women with osteoporosis.

Impact of gastrointestinal events on patient-reported outcomes in Asia-Pacific women with osteoporosis: baseline results of the MUSIC OS-AP study.

The purpose of this study was to describe the impact of gastrointestinal events on patient-reported outcomes and health care resource use among Asia-Pacific women with postmenopausal osteoporosis. The results of this study show that gastrointestinal events decreased adherence, treatment satisfaction, and quality of life in Asia-Pacific women with postmenopausal osteoporosis. PURPOSE: This study aimed to describe the impact of gastrointestinal (GI) events on patient-reported outcomes and health care resource use among Asia-Pacific women with postmenopausal osteoporosis. METHODS: The MUSIC OS-AP study included an observational cohort study of postmenopausal women with osteoporosis. Women were classified as untreated or treated, with treated patients further classified as new or experienced users. Adherence was measured by the Adherence Evaluation of Osteoporosis treatment (ADEOS) questionnaire, treatment satisfaction by the Osteoporosis Patient Satisfaction Questionnaire (OPSAT) while general health-related and osteoporosis-specific quality of life were measured by the European Quality of Life-5 Dimensions (EQ-5D) questionnaire and the Osteoporosis Assessment Questionnaire (OPAQ), respectively. The association of GI events with these outcomes was determined by covariate-adjusted regression analysis of least squares mean differences in the scores of treated patients with and without GI events. Resource utilization was measured as the number of physician visits over the past 3 months, and multivariate regression analysis was used to assess the association of GI events with the likelihood of a visit. RESULTS: The GI event profile, quality of life scores, and resource use were numerically similar in untreated and treated women. The rate of adherence among treated women was higher in experienced than in new users. As indicated by mean scores, experienced users had better quality of life and slightly higher treatment satisfaction and fewer physician visits than new users. Except for adherence in new users, all measures were similarly adversely affected by GI events in both new and experienced users. CONCLUSIONS: GI events decreased adherence, treatment satisfaction, and quality of life in Asia-Pacific women with postmenopausal osteoporosis.

Serum 25-hydroxyvitamin D cutoffs for functional bone measures in postmenopausal osteoporosis.

This study sought to determine the minimal serum 25-hydroxyvitamin D [25(OH)D] concentration required to maintain bone health in postmenopausal women with low bone mass. A serum 25(OH)D concentration of 20 ng/mL rather than 30 ng/mL was appropriate for bone health. INTRODUCTION: There is no consensus on the minimal serum 25-hydroxyvitamin D [25(OH)D] concentration required to maintain bone health. The aim of this study was to investigate the relationship between 25(OH)D measured via liquid chromatography-mass spectrometry (LC-MS/MS), which is the current gold standard, and biochemical markers of bone turnover, PTH, and bone mineral densitometry (BMD). METHODS: The medical records of 750 postmenopausal women newly diagnosed with osteoporosis or osteopenia at Samsung Medical Center from 2009 to 2014 were investigated. Subjects were divided into four groups according to serum 25(OH)D concentration: <10, 10-20, 20-30, and ≥30 ng/mL. Serum concentrations of bone-specific alkaline phosphatase (BS-ALP), carboxy-terminal cross-linking telopeptide of type 1 collagen (CTx), intact PTH (iPTH), and BMD were compared among the four groups using analysis of covariance. Thresholds of 25(OH)D were then assessed using spline plots and locally weighted regression smoothing (LOESS) plots. RESULTS: 25(OH)D was negatively correlated with serum BS-ALP, CTx, and iPTH. Only femur neck and total femur BMD had significant positive relationships with 25(OH)D. Cutoff values of 11.9 and 9.7 ng/mL were estimated from the spline plots of femur neck and total femur BMD, respectively. For iPTH, the LOESS plot showed a steep decrease to a serum 25(OH)D concentration of about 20 ng/mL, followed by a plateau. CONCLUSIONS: According to this study, a serum 25(OH)D concentration of 20 ng/mL, rather than 30 ng/mL, was appropriate for bone health.

Association of circulating dipeptidyl-peptidase 4 levels with osteoporotic fracture in postmenopausal women.

Postmenopausal women with osteoporotic fracture (OF) had higher plasma dipeptidyl-peptidase 4 (DPP4) levels than those without. Furthermore, higher plasma DPP4 levels were significantly associated with higher bone turnover and a higher prevalence of OF. These results indicated that DPP4 may be associated with OF by mediating bone turnover rate. INTRODUCTION: Evidence indicates that dipeptidyl-peptidase 4 (DPP4) plays a distinct role in bone metabolism. However, there has been no report on the association, if any, between circulating DPP4 levels and osteoporosis-related phenotypes, including osteoporotic fracture (OF). Therefore, we performed a case-control study to investigate these associations in postmenopausal women. METHODS: This study was conducted in multiple centers in Korea. We enrolled 178 cases with OF and 178 age- and body mass index-matched controls. OF was assessed by an interviewer-assisted questionnaire and lateral thoracolumbar radiographs. Bone turnover markers (BTMs), bone mineral density (BMD), and plasma DPP4 levels were obtained in all subjects. RESULTS: After adjustment for potential confounders, subjects with OF had significantly higher DPP4 levels than those without (P = 0.021). Higher DPP4 levels were significantly positively associated with higher levels of all BTMs, but not with BMD at all measured sites. The differences in DPP4 levels according to OF status disappeared after an additional adjustment for each BTM, but not after adjustment for any BMD values. BTMs explained approximately half of the relationship between DPP4 and OF. The risk of OF was 3.80-fold (95% confidence interval = 1.53-9.42) higher in subjects in the highest DPP4 quartile than in those in the lowest quartile after adjustment for potential confounders, including femoral neck BMD. CONCLUSIONS: DPP4 may be associated with OF by at least partly mediating the bone turnover rate. Circulating DPP4 levels may be a potential biomarker that could increase the predictive power of current fracture risk assessment models.

Effect of high dietary sodium on bone turnover markers and urinary calcium excretion in Korean postmenopausal women with low bone mass.

BACKGROUND/OBJECTIVES: High salt intake is a well-recognized risk factor of osteoporosis for its modulating effect on calcium metabolism. To understand the effect of dietary sodium on bone turnover, we evaluated the association between urinary sodium excretion and bone turnover markers in Korean postmenopausal women with low bone mass. SUBJECTS/METHODS: A retrospective review of medical records at a single institution identified 537 postmenopausal women who were first diagnosed with osteopenia or osteoporosis between 2008 and 2013. Subjects were stratified by low (<2 g/day, n=77), moderate (2-4.4 g/day, n=354) and high (⩾4.4 g/day, n=106) sodium excretion. A 24-h urine was collected to estimate sodium, calcium and creatinine. Bone turnover markers and calciotropic hormones were measured in serum. Bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry. RESULTS: Sodium intake was positively associated with urinary sodium excretion (P=0.006, r=0.29). Bone turnover markers were significantly higher in the moderate-to-high urinary sodium excretion group (⩾2 g/day) than in the low urinary sodium excretion group (<2 g/day); CTX-I (C-telopeptides of type I collagen) was 21.3% higher (P=0.001) and osteocalcin (OC) was 15.7% higher (P=0.004). Calciotropic hormones and BMD were not significantly different across the sodium excretion groups. CONCLUSIONS: High urinary sodium excretion (⩾2 g/day) increased bone turnover markers in Korean postmenopausal women, suggesting that excessive sodium intake might accelerate bone turnover.

Effects of marathon running on cardiac markers and endothelin-1 in EIH athletes.

The aim of the present study was to determine the changes in cardiac makers and endothelin-1 (ET-1) in marathoners with exercise induced hypertension compared to normotensive controls before and after running a marathon. Among a total of 70 volunteers, 10 marathoners with systolic blood pressure (SBP) greater than 210 mmHg during a treadmill exercise stress test were selected as an exercise-induced hypertension group (EIH) and 10 marathoners with normal SBP were selected as a control group (CON). Blood was collected from all volunteers 2 h before and immediately after a marathon: creatinine kinase (CK), CK-MB, cardiac tropoin-I (cTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), and endothelin-1(ET-1). Cardiac markers, CK, CK-MB, and CK-MB/CK ratio significantly increased in both EIH and CON; significance was not observed between the groups. Significant increases were not observed in high sensitive-C reactive protein (hs-CRP) after the race nor between the groups. Significant increases in cTnI and NT-proBNP were observed after the race in both groups. In addition, EIH showed greater increase than CON after the race. In conclusion, increased vascular tone in EIH during a marathon increased blood pressure and myocardial burden which in turn increased myocardial cell membrane permeability to further increase myocardial tension to the point of cTnI release.

In vivo measurement of human dermis by 1064 nm-excited fiber Raman spectroscopy.

BACKGROUND/AIMS: Although chemical information on the dermis in vivo is highly important in skin research, an efficient method for gathering this information is yet to be developed. Here, we demonstrate that newly developed near-infrared (1064 nm) excited Raman spectroscopy is a powerful method for chemical analysis of human skin in vivo. METHODS: We used a laboratory-constructed Raman spectrometer equipped with a highly sensitive near-infrared detector (Hamamatsu Photonics), an optical fiber probe and a 1064 nm Nd:YAG laser. Raman spectra of porcine skin (in vitro) and human skin (in vivo) were measured with this spectrometer. RESULTS: The Raman spectrum of porcine skin measured from the outer side resembles that of the dermis more than that of the epidermis. The Raman spectra of human skin (cheek, forehead, inner forearm, outer forearm, palm) depend on the portion measured with the probe. The spectra of the forehead and inner forearm show larger lipid signals than that of the palm. CONCLUSIONS: The Raman spectrum of skin measured with the 1064 nm Raman system primarily reflects the chemical composition of the dermis. The 1064 nm excited Raman spectroscopy is useful for research of the dermis and skin appendages.

Profiling signalling pathways of the receptor activator of NF-kappaB ligand-induced osteoclast formation in mouse monocyte cells, RAW264.7.

Cell-based signal chemical genomics can profile the signalling pathway for certain cellular events by using a target-known chemical library. To ascertain its usefulness, the receptor activator of NF-kappaB ligand (RANKL)-induced osteoclastogenesis in mouse monocyte/macrophage cells RAW264.7 was used as an in vitro experimental model. Of 180 target-known inhibitors/activators formatted in a 384-well plate, 8 chemicals were shown to inhibit the osteoclast formation, but 4 chemicals enhanced this process. A variety of references support, or possibly lead one to expect the effects of these 12 chemicals on the cellular process of osteoclastogenesis in RAW264.7 cells, but several signalling pathways were newly found in this study; for example, CA-074 Me inhibiting cathepsin B and nitrendipine blocking the calcium channel could have the potential to inhibit the osteoclast formation as well as bone resorption. This is a simple but very fast and powerful method of profiling the signalling pathway of certain cellular events. Signal chemical genomics could provide invaluable information for the exploration of new target signalling processes and further target-based drug discovery strategies.

Serum gamma-glutamyltransferase within its normal concentration range is related to the presence of diabetes and cardiovascular risk factors.

AIMS: Although many studies have reported an association between serum gamma-glutamyltransferase (GGT) and cardiovascular risk factors, the mechanism of this relationship has not been clarified. METHODS: The medical records of 29,959 subjects (age, median 48, range 14-90 years; 16,706 men, 13,253 women) who visited the Center for Health Promotion at Samsung Medical Center for a medical check-up between January 2001 and December 2003, were investigated. Subjects with hepatic enzyme/GGT concentrations higher than three times the upper limit of the reference range, a positive test for hepatitis C virus antibody, a positive test for hepatitis B virus surface antigen, currently taking anti-diabetic/anti-hypertensive/anti-lipid medication, or a white blood cell (WBC) count higher than 10,000 cells/ml, were excluded. The subjects of each gender were classified into five groups according to their serum GGT concentrations, into quartiles of the normal range of GGT (groups 1, 2, 3 and 4) and into a group with elevated GGT (group 5). RESULTS: As the group number increased (group 1 --> 5), the frequencies of all of the following increased: (i) diabetes and impaired fasting glucose (IFG); (ii) hypertension, obesity (body mass index > or = 27 kg/m2), dyslipidaemia (LDL-cholesterol > or = 4.1 mmol/l and/or triglyceride > or = 2.46 mmol/l, or HDL-cholesterol < 1.16 mmol/l); (iii) metabolic syndrome. Moreover, these significant relationships between GGT concentrations within its normal range and the presence of diabetes/IFG, hypertension, obesity, dyslipidaemia, and metabolic syndrome persisted after adjusting for several clinical and biochemical variables and for the presence of fatty liver based on ultrasonographic findings. Odds ratios (95% CI) for group 4 (highest quartile of normal range of GGT) vs. group 1 (lowest quartile of normal range of GGT); the referent group, were 3.16 (2.15-4.65) for diabetes, 2.24 (1.73-2.90) for IFG, 1.93 (1.59-2.33) for obesity, 1.38 (1.23-1.55) for dyslipidaemia and 2.88 (2.28-3.65) for metabolic syndrome in men. In women, the odds ratios were 2.72 (1.34-5.52), 3.67 (2.26-5.97), 2.10 (1.61-2.74), 1.80 (1.58-2.04) and 3.57 (2.52-5.07), respectively. CONCLUSIONS: Our data show that, even within its normal range, serum GGT concentrations are closely associated with the presence of diabetes and cardiovascular risk factors, and that these associations are independent of a fatty liver by ultrasonography.

Effect of PK11195, a peripheral benzodiazepine receptor agonist, on insulinoma cell death and insulin secretion.

Functional role of peripheral benzodiazepine receptor on mitochondrial membrane in apoptosis and insulin secretion from insulinoma cells was studied. A prototypic peripheral benzodiazepine receptor agonist PK11195 induced insulinoma cell apoptosis, while a central benzodiazepine receptor agonist did not. Death of insulinoma cells by PK11195 was inhibited by cyclosporin A, a blocker of mitochondrial permeability transition pore. Caspase inhibitors further inhibited MIN6N8 cell death. PK11195 induced dissipation of mitochondrial potential and cytochrome c translocation to cytoplasm. PK11195 induced an increase in cytoplasmic [Ca(2+)], which was reversed by cyclosporin A. Rhod-2 staining showed decreased mitochondrial [Ca(2+)] after PK11195 treatment. PK11195 potentiated glucose-induced insulin secretion probably due to the increased cytoplasmic [Ca(2+)]. Calpain was activated following Ca(2+) release, and calpain inhibitors attenuated death of insulinoma cells by PK11195. These results suggest that PK11195 induces mitochondrial potential loss, cytochrome c translocation, increased insulin secretion in conjunction with an increase in cytoplasmic [Ca(2+)] and calpain activation, which collectively leads to apoptosis of insulinoma cells.

Regulation of fibroblast growth factor 2 and fibroblast growth factor receptors by transforming growth factor beta in human osteoblastic MG-63 cells.

Fibroblast growth factor 2 (FGF-2) and its receptors (FGFRs) are important regulators of bone cell function. Although FGF-2 is a major modulator of bone cell function, its expression and regulation in human osteoblasts have not been investigated. We examined FGF-2 messenger RNA (mRNA) expression and regulation in the human osteosarcoma MG-63 cells. Northern analysis revealed that MG-63 cells expressed FGF-2 mRNA transcripts of 7, 4, 2.2, and 1.3 kilobases (kb). In the absence of serum, treatment with transforming growth factor beta (TGF-beta; 0.1-10 ng/ml) increased all FGF-2 mRNA transcripts. Maximal increase was seen with 1 ng/ml of TGF-beta. TGF-beta increased FGF-2 mRNA expression within 2 h and this was sustained for 24 h. Phorbal myristate acetate (PMA; 1 microM) also increased FGF-2 mRNA at 6 h. Time course studies showed that TGF-beta did not significantly alter FGFR1 or FGFR2 mRNA expression in MG-63 cells. Western blotting with anti-human FGF-2 revealed that MG-63 cells synthesize three isoforms of FGF-2 protein of approximately 18, 22/23, and 24 kDa, which were increased after either 6 h or 24 h of treatment with TGF-beta. Increased FGF-2 mRNA and protein expression in response to TGF-beta was markedly reduced by the protein kinase A (PKA) inhibitor H-89. Immunogold labeling of MG-63 cells treated with TGF-beta showed increased labeling for FGF-2 and FGFR2 in the nuclei. In contrast, TGF-beta treatment significantly decreased FGFR1 labeling in the nuclei. These data show that TGF-beta regulates FGF-2 gene expression in human osteosarcoma cells. Furthermore, TGF-beta modulates the cellular localization of FGF-2 and its receptors.

IFN gamma/TNF alpha synergism in MHC class II induction: effect of nicotinamide on MHC class II expression but not on islet-cell apoptosis.

AIMS/HYPOTHESIS: Interferon-gamma (IFN gamma) and TNFalpha synergistically induce pancreatic beta-cell apoptosis. Apart from their direct effect, we studied the possible indirect immunological role of IFNgamma/TNFalpha synergism on pancreatic beta-cell death by investigating MHC class II induction by cytokines. The effect of nicotinamide on the cytokine-induced MHC class II expression and pancreatic beta-cell death was also studied. METHODS: Immunocytochemistry, flow cytometry and RNase protection assay were used to study MHC class II expression. Immunoblotting was done to study downstream signals of IFN gamma. The effects of nicotinamide on islet-cell apoptosis and diabetes mellitus were examined using MTT assay and adoptive transfer model. RESULTS: IFN gamma alone induced MHC class II expression on a small number of insulinoma cells. TNFalpha alone did not induce MHC class II expression, but enhanced IFN gamma-induced MHC class II expression. MHC class II expression by cytokine(s) was due to the induction of class II transactivator (CIITA). Nicotinamide reduced MHC class II expression by cytokine(s) but did not protect insulinoma-cell apoptosis by IFN gamma and TNFalpha in combination or protect against the development of diabetes mellitus after adoptive transfer of diabetogenic lymphocytes. CONCLUSION/INTERPRETATION: IFN gamma and TNFalpha synergistically induced MHC class II expression on insulinoma cells through the induction of CIITA; nicotinamide reduced the expression of cytokine-induced MHC class II expression on insulinoma cells through its effect on CIITA expression; and the preventive effect of nicotimamide on Type I (insulin-dependent) diabetes mellitus is probably due to its effect of MHC class II expression rather than that on islet cell apoptosis.

Selective interaction of triazole derivatives with DWF4, a cytochrome P450 monooxygenase of the brassinosteroid biosynthetic pathway, correlates with brassinosteroid deficiency in planta.

Brassinazole, a synthetic chemical developed in our laboratory, is a triazole-type brassinosteroid biosynthesis inhibitor that induces dwarfism in various plant species. The target sites of brassinazole were investigated by chemical analyses of endogenous brassinosteroids (BRs) in brassinazole-treated Catharanthus roseus cells. The levels of castasterone and brassinolide in brassinazole-treated plant cells were less than 6% of the levels in untreated cells. In contrast, campestanol and 6-oxocampestanol levels were increased, and levels of BR intermediates with hydroxy groups on the side chains were reduced, suggesting that brassinazole treatment reduced BR levels by inhibiting the hydroxylation of the C-22 position. DWF4, which is an Arabidopsis thaliana cytochrome P450 isolated as a putative steroid 22-hydroxylase, was expressed in Escherichia coli, and the binding affinity of brassinazole and its derivatives to the recombinant DWF4 were analyzed. Among several triazole derivatives, brassinazole had both the highest binding affinity to DWF4 and the highest growth inhibitory activity. The binding affinity and the activity for inhibiting hypocotyl growth were well correlated among the derivatives. In brassinazole-treated A. thaliana, the CPD gene involved in BR biosynthesis was induced within 3 h, most likely because of feedback activation caused by the reduced levels of active BRs. These results indicate that brassinazole inhibits the hydroxylation of the C-22 position of the side chain in BRs by direct binding to DWF4 and that DWF4 catalyzes this hydroxylation reaction.

Routine measurement of serum calcitonin is useful for early detection of medullary thyroid carcinoma in patients with nodular thyroid diseases.

BACKGROUND: Medullary thyroid carcinoma (MTC) is characterized by a high concentration of serum calcitonin. Routine measurement of serum calcitonin concentration has been advocated for detection of MTC among patients with nodular thyroid diseases. However, a minimal to moderate increase of serum calcitonin concentration has been frequently observed in diseases other than MTC. Fine-needle aspiration cytology (FNAC) is not a reliable method for detection of MTC. Therefore, we evaluated the usefulness of routine measurement of serum calcitonin concentration in patients with nodular thyroid diseases, and studied the validity of pentagastrin stimulation test and FNAC in these patients. SUBJECTS AND METHODS: We performed routine measurement of serum calcitonin concentrations in 1,448 patients (male, 285, female, 1,163) with nodular thyroid diseases. The average age was 46 years (range, 14-86 years). Initial examination included thyroid examination, thyroid scan or ultrasonography, measurements of serum free triiodothyronine) (T3), free thyroxine (T4), thyrotropin (TSH) levels, and antithyroid autoantibodies. FNAC was performed in all patients who had palpable or visible thyroid nodule by ultrasonography, and pentagastrin stimulation test was performed in 39 patients who consented. Serum calcitonin concentration was measured with a two-site immunoradiometric assay using commercial kits. We also measured the serum calcitonin concentration in 407 healthy subjects without thyroid or nonthyroid diseases. RESULTS: Serum calcitonin concentration was 10 pg/mL or less in 403 normal subjects (99.0 percentile), and 11-13 pg/mL in the remaining 4 subjects. We found that 56 (3.87%) of 1,448 patients with nodular thyroid diseases had serum calcitonin level above 10 pg/mL. Ten patients (0.69%) with histologically confirmed MTC were detected by the routine measurement of serum calcitonin. The prevalence of MTC was 5.2% in 194 patients with thyroid carcinoma. Five of 10 patients with MTC had basal serum calcitonin level above 100 pg/mL. The remaining 5 patients had minimal or moderate elevation of basal serum calcitonin (range, 12-86 pg/mL). Serum calcitonin concentration increased to more than 100 pg/mL by pentagastrin in all patients with MTC (2.4- to 37.7-fold increase). FNAC suggested MTC in only 2 patients (22.2%), and failed to diagnose MTC in 7 patients. FNAC was not performed in 1 patient with MTC, because he had no visible mass by ultrasonography. CONCLUSION: These results suggested that routine measurement of serum calcitonin is useful in the early detection of MTC among patients with nodular thyroid diseases. Pentagastrin stimulation test may also be a reliable way for evaluating thyroid nodular patients with mild or moderate elevation of serum calcitonin concentrations. However, FNAC was not sensitive in detecting MTC. We recommend routine measurement of serum calcitonin concentration in patients with nodular thyroid diseases.

The effects of dexamethasone on insulin release and biosynthesis are dependent on the dose and duration of treatment.

Complex results concerning the effect of glucocorticoids on insulin secretion have been reported. The aim of this study is to clarify the direct effects of glucocorticoids on pancreatic islets and to determine whether the effect of glucocorticoids on insulin biosynthesis or release is dependent on the dose and duration of treatment with glucocorticoid. Studies on insulin secretion and biosynthesis were performed with different concentrations (0, 1, 10, 100 nmol/l) and durations (1 and 6 h) of treatment with dexamethasone (dexa) in rat pancreatic islets. (1) One nmol/l dexa had no inhibitory effect on insulin secretion and biosynthesis. Ten and 100 nmol/l had an inhibitory effect on insulin secretion, which was mainly due to suppression of the first phase of insulin secretion. (2) Insulin content was significantly increased regardless of the concentration in 1-h treated islets. However, insulin content was markedly diminished with 100 nmol/l dexa in 6-h treated islets. (3) The preproinsulin mRNA expression of 6-h treated islets was suppressed in a dose-dependent manner. Our data revealed that, in the condition of short-term and low-dose glucocorticoid exposure, insulin secretion and biosynthesis are not affected. The secretory process of insulin seems to be the initial step of the inhibitory action of glucocorticoid. Both insulin release and biosynthesis are inhibited by chronic exposure to high dose dexamethasone. It can be concluded that glucocorticoid might be involved in the multisteps of insulin release and biosynthesis.

Synthesis and biological activity of 4'-methoxy derivatives of abscisic acid.

Replacing the 4'-carbonyl group of abscisic acid with a methoxy group does not affect the abscisic acid (ABA)-like activities of the product in barley aleurone protoplasts, although the reduction of ABA to 4'-hydroxyl derivatives significantly reduces the ABA-like activity of the products. This suggests that methoxy derivatives of abscisic acid might be used to produce probes for ABA binding proteins.

Significance of Pro12Ala mutation in peroxisome proliferator-activated receptor-gamma2 in Korean diabetic and obese subjects.

Peroxisome proliferator-activated receptors (PPARs) are a nuclear hormone receptor superfamily of ligand-activated transcription factors, and the PPARgamma subtype regulates adipocyte differentiation, lipid metabolism, and insulin sensitivity. There have been several reports on the relationship between the PPARgamma2 Pro12Ala genotype and obesity or diabetes in Caucasians. The objective of this study was to examine the relationship between this mutation and obesity or diabetes in Korean subjects. Two hundred and twenty-nine Korean subjects, including 111 obese subjects (body mass index, >25 kg/m2) were included in this study. One hundred and eleven subjects had normal glucose tolerance, 60 had impaired glucose tolerance, and 58 had diabetes mellitus. We evaluated these subjects for the Pro12Ala mutation in the PPARgamma gene using PCR-restriction fragment length polymorphism. Allele frequencies of the Pro12Ala missense mutation of PPARgamma2 were not different among Korean subjects with normal glucose tolerance (qAla = 0.045), those with impaired glucose tolerance (qAla = 0.033), and those with diabetes mellitus (qAla = 0.043; P > 0.05). Allele frequencies of PPARgamma2 Ala in obese subjects (qAla = 0.036) were not significantly different from those in nonobese subjects (qAla = 0.047). These results suggest that the Pro12Ala mutation in PPARgamma is not associated with either diabetes or obesity and may not be an important determinant of obesity or diabetes in Korean subjects.

Characterization of brassinazole, a triazole-type brassinosteroid biosynthesis inhibitor.

Screening for brassinosteroid (BR) biosynthesis inhibitors was performed to find chemicals that induce dwarfism in Arabidopsis, mutants that resembled BR biosynthesis mutants that can be rescued by BR. Through this screening experiment, the compound brassinazole was selected as the most potent chemical. In dark-grown Arabidopsis, brassinazole-induced morphological changes were nearly restored to those of wild type by treatment with brassinolide. The structure of brassinazole is similar to pacrobutrazol, a gibberellin biosynthesis inhibitor. However, in assays with cress (Lepidium sativum) plants, brassinazole-treated plants did not show recovery after the addition of gibberellin but showed good recovery after the addition of brassinolide. These data demonstrate that brassinazole is a specific BR biosynthesis inhibitor. Brassinazole-treated cress also showed dwarfism, with altered leaf morphology, including the downward curling and dark green color typical of Arabidopsis BR-deficient mutants, and this dwarfism was reversed by the application of 10 nM brassinolide. This result suggests that BRs are essential for plant growth, and that brassinazole can be used to clarify the function of BRs in plants as a complement to BR-deficient mutants. The brassinazole action site was also investigated by feeding BR biosynthesis intermediates to cress grown in the light.

Treatment of dark-grown Arabidopsis thaliana with a brassinosteroid-biosynthesis inhibitor, brassinazole, induces some characteristics of light-grown plants.

When a brassinosteroid biosynthesis inhibitor, brassinazole (Brz), was applied at concentrations ranging from 0.1 to 2 microM. Arabidopsis thaliana (L.) Heynh seedlings grown in the dark exhibited morphological features of light-grown plants, i.e. short hypocotyls, expanded cotyledons, and true leaves, in a dose-dependent manner. Control (non Brz-treated) seedlings grown in the dark for 40 d did not develop leaf primordia. However, treatment with the lowest concentration of Brz induced the development of leaf buds, although it hardly induced any short hypocotyls, and treatment with the highest concentration of Brz induced both short hypocotyls and leaves. Labeling experiments with the thymidine analogue 5-bromo-2'-deoxyuridine revealed that amplification of cell nuclei and organellar nucleoids is activated in the shoot apical meristems of dark-grown Brz-treated seedlings. These results suggest that Brz-treatment induces development of true leaves. Furthermore, condensation and scattering of plastid nucleoids, which is known to occur during the differentiation of etioplasts into chloroplasts, was observed in the plastids of dark-grown Brz-treated cotyledons. In addition, high levels of ribulose-1,5-bisphosphate carboxylase-oxygenase proteins accumulated in the plastids of the cotyledons. Electron microscopy showed that the plastids were etioplasts with a prolamellar body and few thylakoid membranes. These results suggest that Brz treatment in the dark induces the initial steps of plastid differentiation, which occur prior to the development of thylakoid membranes. This is a novel presumed function of brassinosteroids. These cytological changes seen in Brz-treated Arabidopsis were exactly the same as those seen in a brassinosteroid-biosynthesis-deficient mutant, det2, supporting the hypothesis that Brz has no side-effects except inhibiting brassinosteroid biosynthesis, and should prove a useful tool in clarifying the role of brassinosteroids.