Hyperphosphatemia is associated with cardiac valve calcification in chronic hypoparathyroidism.

PURPOSE: To evaluate the association between metabolic abnormalities and cardiovascular risk factors in patients with chronic hypoparathyroidism (HPP). PATIENTS AND METHODS: Patients 18 years and older, glomerular filtration > 30 mL/min/1.73 m2 and no documented coronary artery disease were selected. Serum calcium, phosphorus, glucose, lipids, PTH, 25(OH)D and FGF23 were measured. Cardiovascular risk was estimated by the European Society of Cardiology (ESC) calculator. Transthoracic echocardiogram and carotid ultrasound were performed to detect carotid plaques (CP), carotid intima-media thickness (IMT), cardiac valve calcification (CVC), and left ventricular hypertrophy (LVH). RESULTS: Thirty-seven patients (94.6% female), aged 56.0 ± 13.5 years and HPP duration 7.0 (4.0; 11.3) years, were included. Fifteen were classified as low cardiovascular risk, 9 as intermediate risk, 9 as high risk and none as very high risk. The prevalence of CP, CVC and LVH was 24.3%, 24.3% and 13.5%, respectively. IMT values were within normal ranges in all cohort. FGF23 were not associated with CP, IMT, CVC or LVH. After logistic regression, phosphorus was the only significant metabolic variable impacting CVC in univariate analysis (OR 2.795; 95% CI 1.132-6.905; p = 0.026), as well as in the multivariate analysis (OR 3.572; 95% CI 1.094-11.665; p = 0.035). Analysis by ROC curve showed serum phosphorus > 5.05 mg/dL (AUC 0.748; CI 0.584-0.877; p = 0.05) as the best cutoff point associated with valve heart calcification (sensitivity 78%; negative predictive value 91.3%). CONCLUSION: Hyperphosphatemia was associated with CVC in HPP patients. Further studies are needed to investigate whether the control of hyperphosphatemia may reduce cardiovascular risk in this population.

Photonic effects in natural nanostructures on Morpho cypris and Greta oto butterfly wings.

Photonic crystals are some of the more spectacular realizations that periodic arrays can change the behavior of electromagnetic waves. In nature, so-called structural colors appear in insects and even plants. Some species create beautiful color patterns as part of biological behavior such as reproduction or defense mechanisms as a form of biomimetics. The interaction between light and matter occurs at the surface, producing diffraction, interference and reflectance, and light transmission is possible under suitable conditions. In particular, there are two Colombian butterflies, Morpho cypris and Greta oto, that exhibit iridescence phenomena on their wings, and in this work, we relate these phenomena to the photonic effect. The experimental and theoretical approaches of the optical response visible region were studied to understand the underlying mechanism behind the light-matter interaction on the wings of these Colombian butterflies. Our results can guide the design of novel devices that use iridescence as angular filters or even for cosmetic purposes.

Clodronate exerts an anabolic effect on articular chondrocytes mediated through the purinergic receptor pathway.

OBJECTIVE: Bisphosphonates are commonly used anti-osteoporotic drugs which have controversial effects on joint diseases including osteoarthritis. Certain bisphosphonates have been shown to have anabolic effects on cartilage which could have important ramifications for their proposed effects in vivo; however, the underlying mechanisms are poorly understood. Thus, the purpose of this study was to characterize the effects of clodronate on primary articular chondrocyte metabolism and to determine the underlying signaling pathways responsible. DESIGN: The effects of clodronate and pamidronate on extracellular matrix (ECM) biosynthesis, accumulation and MMP-13 activity were observed in high density, 3D cultures of bovine articular chondrocytes for up to 4 weeks were evaluated. Mechanisms were delineated by measuring intracellular Ca(2+) signaling and the effects of pharmacologic inhibition of the purinergic receptor pathway. RESULTS: Clodronate (100 µM) induced an anabolic effect (increased biosynthesis by 13-14%) which resulted in an 89-90% increase in ECM accumulation after 4 weeks of culture and without an associated effect on matrix turn-over. Stimulation by clodronate resulted in a 3.3-fold increase in Ca(2+) signaling and pharmacological inhibitor experiments suggested that the anabolic effects exerted by clodronate are transduced through the purinergic receptor pathway. CONCLUSIONS: These findings support the previous notion that certain bisphosphonates may be useful as adjunctive therapies to potentially ameliorate progression of cartilage degeneration and improve arthritis management.

Adaptations to changing speed, load, and gradient in human walking: cost of transport, optimal speed, and pendulum.

It has been observed that the optimal speed (OPT) of human walking is independent of load on level surfaces because of the unaltered trajectory of the center of mass and consequent conservation of the pendular mechanism. However, the role of the inverted pendulum mechanism that combines speed, load, and gradient during walking remains unknown. In the present study, 10 subjects walked on a treadmill, with and without loading (25% of the body mass), at different speeds and slopes (0%, +7%, and +15%). The three-dimensional motion and VO2 were simultaneously registered. The mechanical external and internal work and the cost of transport (C) changed with the speed and gradient, but the load only affected C. OPT decreased with increasing gradient, and the pendular mechanics (R) was modified mainly as a result of changes in speed and gradient. OPT and R were independent of the load in these gradients. Remarkably, R increased with increasing speed and decreased (to 30%) with an increasing gradient; moreover, R was independent of load. Therefore, the energy-saving strategy by the pendular mechanism persists, although at a diminished level, in loaded walking on gradients and partially explains the OPT in this condition.