Trattamento dell'iperparatiroidismo secondario: calciomimetici, attivatori selettivi del recettore della vitamina D (VDRAs) o terapia combinata

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Il trattamento dell'iperparatiroidismo secondario con gli analoghi della vitamina D:

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Response of vegetation to drought time-scales across global land biomes

We evaluated the response of the Earth land biomes to drought by correlating a drought indexwith three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of thewater deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions havemechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ fromthose operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change

Therapeutic options for mineral metabolism disorders in dialysis patients: a case report

Mineral metabolism disorders are well-recognized complications in patients with chronic kidney disease (CKD). Furthermore, hyperphosphatemia and secondary hyperparathyroidism are associated with both renal osteodystrophy and cardiovascular disease. During the last 5 years, new therapeutic options have become available to treat these conditions in CKD. We describe the case of a 70-year-old lady with a dialysis history of 5 years and a number of cardiovascular risk factors (hypertension, hypercholesterolemia and obesity). Unfortunately, the patient was poorly compliant with any pharmaceutical treatment. After 2 years, a pharmacological approach with a low dosage of calcium salts and sevelamer HCl, subsequently changed to lanthanum carbonate, intravenous paricalcitol, and cinacalcet HCl reached the goals suggested by the current guidelines. Every nephrologist should look at the pathogenesis and treatment of hyperphosphatemia and secondary hyperparathyroidism. New options are now available and may help the clinician to obtain satisfactory short- and long-term outcomes in the treatment of this disease

Pathogenesis and treatment of vascular calcification in CKD

Increased vascular calcification is a major cause of cardiovascular events in patients with chronic kidney disease (CKD). It is the result of an active ossification process counteracted by ''bone'' proteins such as osteopontin, alkaline phosphatase, osteoprotegerin, and osteocalcin. Chronic kidney disease - mineral and bone disorder (CKD-MBD) is a systemic disorder of mineral and bone metabolism that occurs in CKD. In addition to abnormalities in the serum calcium and phosphate profile, CKD-MBD is characterized by abnormalities of bone turnover, mineralization, volume and growth as well as vascular calcification. Considering that the presence and extent of vascular calcification in CKD portend a poor prognosis, many efforts have been made to shed light on this complicated phenomenon to prevent vascular calcium deposition and its progression. Indeed, careful control of calcium load, serum phosphate and parathyroid hormone along with the use of calcium-free phosphate binders and vitamin D receptor activators represent a new therapeutic armamentarium to improve quality of life and reduce mortality in CKD