Determination of local atomic displacements in CeO(1-x)F(x)BiS2 system

We have used Bi and Ce L3-edges extended x-ray absorption fine structure measurements to study local structure of CeO(1-x)F(x)BiS2 system as a function of F-substitution. The local structure of both BiS2 active layer and CeO1-xFx spacer layer changes systematically. The in-plane Bi-S1 distance decreases (ΔRmax ∼ 0.08 Å) and the out-of-plane Bi-S2 distance increases (ΔRmax ∼ 0.12 Å) with increasing F-content. On the other hand, the Ce-O/F distance increases (ΔRmax ∼ 0.2 Å) with a concomitant decrease of the Ce-S2 distance (ΔRmax ∼ 0.15 Å). Interestingly, the Bi-S1 distance is characterized by a large disorder that increases with F-content. The results provide useful information on the local atomic displacements in CeO(1-x)F(x)BiS2, that should be important for the understanding of the coexistence of superconductivity and low temperature ferromagnetism in this system.

Prognostic value of serum parathyroid hormone level in acute decompensated heart failure

BACKGROUND

Secondary hyperparathyroidism develops as a compensatory response to chronic heart failure (HF) and renal failure. The role of parathyroid hormone (PTH) level in acute decompensated HF remains unclear. The aim of this study was therefore to investigate the relationships among mortality, renal function, and serum PTH level in acute decompensated HF patients. METHODS AND RESULTS: A total of 266 consecutive patients admitted for acute decompensated HF without acute coronary syndrome (78±12 years; 48% male) were enrolled. Demographic, clinical, and laboratory characteristics were obtained on admission.During 1-year follow-up, 65 patients (24%) died. Serum PTH level on admission was within the normal range (10-65 pg/ml) in 108 patients (41%), of whom 39 (15%) had low-normal PTH (10-40 pg/ml). On Kaplan-Meier analysis all-cause mortality was significantly higher in patients with low-normal PTH than in those with high-normal (40-65 pg/ml) or high (>65 pg/ml) PTH (log-rank test). On univariate and multivariate Cox regression analysis, low-normal PTH was significantly associated with increased all-cause mortality (unadjusted HR, 2.88; 95% CI: 1.69-4.91; P<0.001; adjusted HR, 3.84; 95% CI: 1.54-9.57; P=0.004).

CONCLUSIONS

In patients with acute decompensated HF resulting in hospitalization, low-normal PTH on admission is associated with increased all-cause mortality, regardless of renal function.

Profile of changes in bone turnover markers during once-weekly teriparatide administration for 24 weeks in postmenopausal women with osteoporosis

SUMMARY

Changes in bone turnover markers with weekly 56.5 μg teriparatide injections for 24 weeks were investigated in women with osteoporosis. Changes in bone turnover markers 24 h after each injection of teriparatide were constant. During the 24 week period, bone formation markers increased and baseline bone resorption marker levels were maintained.

INTRODUCTION

This study aimed to clarify the changes in bone turnover markers during 24 weeks of once-weekly teriparatide injections in postmenopausal women with osteoporosis.

METHODS

The 24 h changes in pharmacokinetics (PK), calcium metabolism, and bone turnover markers (serum osteocalcin, procollagen type I N-terminal propeptide (P1NP), urinary cross-linked N-telopeptide of type I collagen (NTX), deoxypiridinoline (DPD)) after each injection of 56.5 μg teriparatide at the data collection weeks (0, 4, 12, and 24 weeks) were investigated. The changes were evaluated by comparison with the data at 0 h in each data collection week.

RESULTS

Similar 24 h changes in each parameter after injection of teriparatide were observed in each data collection week. Serum calcium increased transiently, and intact PTH decreased 4-8 h after injection; serum calcium subsequently returned to baseline levels. Calcium and intact PTH levels decreased for 24 weeks. Although serum osteocalcin decreased at 24 h, it was significantly increased at 4 weeks. P1NP decreased transiently and then increased significantly at 24 h. P1NP was significantly increased at 4 weeks. Urinary NTX and DPD were significantly increased transiently and then decreased at 24 h. The urinary DPD level decreased significantly at 4 weeks.

CONCLUSIONS

Twenty-four hour changes in PK, calcium metabolism, and bone turnover markers showed the same direction and level after once-weekly teriparatide injections for 24 weeks, with no attenuation of the effect over time. After 24 weeks, the bone formation marker, serum osteocalcin, increased significantly, but the serum P1NP, did not. Bone resorption markers decreased or remained the same.

The effects of once-weekly teriparatide on hip structure and biomechanical properties assessed by CT

SUMMARY

Once-weekly administration of 56.5 μg teriparatide improved cortical bone parameters and biomechanical parameters at the proximal femur by CT geometry analysis.

INTRODUCTION

The aim of this study was to evaluate the effects of weekly administration of teriparatide [human PTH (1-34)] on bone geometry, volumetric bone mineral density (vBMD), and parameters of bone strength at the proximal femur which were longitudinally investigated using computed tomography (CT).

METHODS

The subjects were a subgroup of a recent, randomly assigned, double-blind study (578 subjects) comparing the anti-fracture efficacy of a once-weekly subcutaneous injection of 56.5 μg teriparatide with placebo (TOWER trial).

RESULTS

Sixty-six ambulatory postmenopausal women with osteoporosis were enrolled at 15 study sites having multi-detector row CT, and included women injected with teriparatide (n = 29, 74.2 ± 5.1 years) or with placebo (n = 37, 74.8 ± 5.3 years). CT data were obtained at baseline and follow-up scans were performed at 48 and 72 weeks. The data were analyzed to obtain cross-sectional densitometric, geometric, and biomechanical parameters including the section modulus (SM) and buckling ratio (BR) of the femoral neck, inter-trochanter, and femoral shaft. We found that once-weekly teriparatide increased cortical thickness/cross-sectional area (CSA) and total area, and improved biomechanical properties (i.e., decreasing BR) at the femoral neck and shaft. Teriparatide did not change the cortical perimeter.

CONCLUSIONS

Our longitudinal analysis of proximal femur geometry by CT revealed that once-weekly administration of 56.5 μg teriparatide improved cortical bone parameters at the femoral neck and shaft and also improved biomechanical parameters.

Serum osteocalcin levels are inversely associated with abdominal aortic calcification in men with type 2 diabetes mellitus

We found that serum osteocalcin (OC) and undercarboxylated OC (ucOC) levels were negatively associated with abdominal aortic calcification in type 2 diabetes mellitus (T2DM) men. This finding suggests that circulating OC and ucOC are not only related to glucose or fat metabolism but also to arteriosclerosis.

INTRODUCTION

Recent studies revealed that serum osteocalcin levels were associated with not only bone metabolism but also glucose and fat metabolism. However, the relationship between serum OC levels and arteriosclerosis remains controversial. We examined whether or not bone metabolic markers including OC are associated with abdominal aortic calcification in patients with type 2 diabetes mellitus.

METHODS

We recruited 118 men and 100 postmenopausal women with T2DM. We evaluated the abdominal aortic calcification score (ACS) on a lateral lumbar radiograph and examined the association between serum OC or undercarboxylated OC levels and ACS.

RESULTS

The ACS of 3 and greater, which corresponded well to the highest quartile, was significantly and negatively associated with serum OC and ucOC levels in men by logistic regression analyses after adjusting for age, BMI, serum levels of creatinine and LDL cholesterol, radial bone mineral density, smoking, duration of DM, hemoglobin A1c, and the index of insulin resistance [odds ratio (OR) 0.36, 95 % confidence interval (CI) 0.19-0.70, P < 0.005, and OR 0.28, 95 % CI 0.12-0.69, P < 0.01, per standard deviation increase in OC and ucOC, respectively]. These observations were still significant after an additional adjustment for other bone markers. In contrast, there were no significant relationships with serum OC or ucOC levels and ACS in women.

CONCLUSIONS

These findings suggest that serum OC and ucOC levels are associated with not only bone metabolism but also arteriosclerosis in men, but not in women with type 2 diabetes mellitus.

Advanced glycation end products-induced vascular calcification is mediated by oxidative stress: functional roles of NAD(P)H-oxidase

Vascular calcification, especially medial artery calcification, is associated with increased morbidity and mortality in patients with diabetes mellitus and end-stage kidney disease. Advanced glycation end products (AGEs) accumulated in these patients may be associated with vascular calcification, although their actions are obscure. Since AGEs can induce oxidative stress, which leads to vascular damage, we investigated an in vitro study to elucidate the effects of AGEs and the roles of NAD(P)H oxidase in the pathogenesis of vascular calcification. A7r5, rat vascular smooth muscle cells (VSMCs) were incubated in calcification medium with glycolaldehyde-derived AGE (AGE3) to measure calcium deposition and 8-hydroxydeoxyguanosine (8-OHdG) and to determine mRNA levels of osteopontin (OPN), osteocalcin (OCN), Runx2, Nox-1, Nox-4, and p22(phox) by real-time PCR. Calcium deposition was increased by AGE3 in a dose-dependent manner (100-300 μg/dl) in A7r5 cells. Expression levels of Runx2, OPN, and OCN mRNAs were significantly higher in AGE3 treatment than those in control BSA. Increased 8-OHdG concentration in the culture medium and higher expression of Nox-1, Nox-4, and p22(phox) mRNAs (3-6-fold) were observed in cells treated with AGE3. AGE3-stimulated calcium deposition was significantly decreased in the cells transfected by either small interfering RNA for Nox-4 or p22(phox), compared to the controls. In contrast, no significant effect was shown in silencing of Nox-1. Excessive oxidative stress and osteoblastic transition of VSMCs are involved in the pathogenesis of AGEs-induced vascular calcification. NAD(P)H oxidase plays important roles in this process.

Undercarboxylated osteocalcin is positively associated with free testosterone in male patients with type 2 diabetes mellitus

Although a recent study showed that undercarboxylated osteocalcin (ucOC) is important for male fertility and testosterone production by testes, little is known about the relationship between ucOC and testosterone in humans. We found for the first time that ucOC is positively associated with free testosterone in men with type 2 diabetes.

INTRODUCTION

The ucOC has been shown to play a key role in energy metabolism as an endocrine hormone. Although a recent animal study demonstrated that ucOC is also important for male fertility and testosterone production by the testes, association between serum osteocalcin and testosterone levels has not been understood in humans.

METHODS

Sixty-nine male patients with type 2 diabetes were recruited and chemical bone markers [total osteocalcin (TOC), ucOC, bone-specific alkaline phosphatase (BAP), and urinary N-terminal cross-linked telopeptide of type I collagen (uNTX)], gonadotropic hormones [luteinizing hormone (LH) and follicle-stimulating hormone (FSH)], and free testosterone (FT) were measured.

RESULTS

Multiple regression analysis showed that ucOC and ucOC/TOC ratio were associated positively with FT and negatively with LH (for ucOC, β = 0.30, p = 0.042 and β = -0.52, p = 0.048; for ucOC/TOC ratio, β = 0.31, p = 0.031 and β = -0.54, p = 0.036, respectively) independently of age, duration of diabetes, body mass index, and hemoglobin A1c. ucOC and ucOC/TOC ratio were significantly associated with FT even after adjusting for LH and FSH (β = 0.24, p = 0.042 and β = 0.25, p = 0.031, respectively). However, neither TOC, BAP, nor uNTX was associated with the gonadotropic hormones or FT levels.

CONCLUSIONS

The present study indicates for the first time that ucOC is associated positively with FT and negatively with LH in type 2 diabetes. These findings support the recent evidence that ucOC is involved in testosterone production in male subjects.

Effects of a single injection of teriparatide on bone turnover markers in postmenopausal women

This study investigated the effects of a single administration of teriparatide on bone turnover markers in postmenopausal women. Teriparatide caused a transient increase in bone resorption and inhibition of bone formation followed by a subsequent increase in bone formation and a decrease in resorption that lasted at least 1 week.

INTRODUCTION

This study aims to investigate the effects of a single subcutaneous administration of teriparatide on bone turnover markers to elucidate why once weekly intermittent administration of teriparatide is effective on osteoporosis.

METHODS

Pharmacokinetics and calcium metabolism and bone turnover parameters were measured in 30 postmenopausal women after two doses of teriparatide (28.2 or 56.5 μg injection) or placebo in a randomized, double-blind, placebo-controlled study.

RESULTS

Teriparatide plasma concentration increased in a dose-dependent manner, and the maximum concentration was achieved 1 h after injection. Serum levels of calcium and phosphorus were transiently increased and decreased after teriparatide injection, respectively. Calcium metabolism returned to baseline levels 24 h later. Two days after injection, the serum level of 1,25-dihydroxy vitamin D was increased by ~80 % from baseline for both doses of teriparatide. Serum levels of osteocalcin and procollagen type I N-terminal propeptide decreased during the first 24 h followed by a ~10 % increase for 14 days. The serum level of cross-linked N-telopeptide (NTX) of type I collagen increased during the first 24 h followed by a 10 to 12 % dose-dependent suppression from baseline for 14 days. Urinary cross-linked C-telopeptide of type I collagen changes occurred in the same direction as serum NTX, but not dose dependently.

CONCLUSION

A single administration of teriparatide caused an immediate, transient increase in bone resorption and inhibited bone formation followed by an increase in bone formation and decrease in resorption for ≥1 week. These findings may provide proof for the effect of a once-weekly regimen of teriparatide on bone turnover.

Interrelationship between haemodynamic state and serum intact parathyroid hormone levels in patients with chronic heart failure

OBJECTIVE

To assess the impact of serum intact parathyroid hormone (PTH) levels on haemodynamic state and their relations by comparing plasma B-type natriuretic peptide (BNP) levels.

DESIGN

Cross-sectional study in molecular epidemiology.

SETTING

Mie University Hospital, Tsu, Japan.

PATIENTS

Consecutive 105 patients with chronic heart failure (CHF).

MAIN OUTCOME MEASURES

Serum intact PTH and plasma BNP levels were assessed simultaneously with right heart catheterisation.

RESULTS

Although serum intact PTH levels (46±25 pg/ml) were within the normal range (<65 pg/ml) in 87% of patients, log-transformed intact PTH levels significantly correlated with pulmonary capillary wedge pressure (PCWP: 15±9 mm Hg, r=0.55, p<0.05) and heart rate (73±14/min, r=0.40, p<0.05), whereas log-transformed intact PTH levels were inversely correlated with stroke volume index (SVI: 38±11 ml/m(2), r=-0.52, p<0.05) and cardiac index (2.6±0.7 l/min/m(2), r=-0.41, p<0.05) in all patients. PCWP and SVI were independent determinants of log-transformed intact PTH levels (β=0.40 and -0.37, p<0.05, respectively) after adjusting for variables associated with PTH. Conversely, after adjusting for variables associated with CHF, log-transformed intact PTH levels were an independent determinant of PCWP, SVI, heart rate and cardiac index (β=0.38, -0.33, 0.32, and -0.25, p<0.05, respectively), and might be defined as a superior determinant of SVI and cardiac index compared with log-transformed BNP levels using stepwise multivariate regression analyses.

CONCLUSIONS

Increased PCWP and decreased SVI independently contribute to elevated intact PTH in patients with CHF.

Short-term effects of low-dose tolvaptan on hemodynamic parameters in patients with chronic heart failure

BACKGROUND

We evaluated the short-term effects of low-dose tolvaptan treatment on hemodynamic parameters in patients with chronic heart failure (HF).

METHODS

We studied 22 patients (69 ± 10 years) with chronic HF and excess fluid retention despite receiving appropriate medical therapy, including loop and/or thiazide diuretics. The therapeutic effects of low-dose (7.5mg) once-daily tolvaptan on hemodynamics associated with changes in fluid balance and neurohumoral activations were investigated after a seven day treatment period.

RESULTS

After the treatment period, body weight decreased (-2.7 ± 2.3 kg) associated with increases in daily urine output. Whereas plasma arginine-vasopressin levels, serum aldosterone concentration, and plasma renin activity mildly increased, plasma levels of B-type natriuretic peptide and atrial natriuretic peptide significantly decreased after tolvaptan treatment. Serum electrolytes were not adversely affected by tolvaptan treatment. Although cardiac index and systemic vascular resistance index remained unchanged, mean pulmonary artery wedge pressure (22 ± 7 mmHg vs. 17 ± 7 mmHg, p<0.05), mean right atrial pressure (12 ± 5 mmHg vs. 9 ± 5 mmHg, p<0.05), mean pulmonary artery pressure (32 ± 9 mmHg vs. 25 ± 7 mmHg, p<0.05), and pulmonary vascular resistance index (332 ± 207 dynes/cm(-5)/m(2) vs. 245 ± 110 dynes/cm(-5)/m(2), p<0.05) significantly decreased after tolvaptan treatment. The extent of the reduction in pulmonary vascular resistance index after tolvaptan treatment strongly correlated with baseline values.

CONCLUSIONS

Short-term treatment with low-dose tolvaptan improved hemodynamic parameters and correlated with significant fluid removal in patients with chronic HF.