1,241 research outputs found
Biofortified Crops as Part of a More Diverse Diet
No full textIFPRI Policy Seminar “Getting to One Billion: Scaling Up Biofortification” on October 21, 2015, Presentation by Namukolo Covic
What would we like to know, and what do we not know about fibroblast growth factor 23?
No full textRecently, a new view of the molecular mechanisms of phosphate homeostasis and secondary hyperparathyroidism pathogenesis has been proposed, with fibroblast growth factor 23 (FGF23) as a novel player in the field. FGF23 is a 32-kDa peptide secreted by the osteocytes involved in the control of phosphate homeostasis and calcitriol metabolism. FG23 is constantly elevated in advanced chronic kidney disease (CKD) patients, and recent studies have indicated that high levels are associated with the progression of CKD and with higher mortality rates in hemodialysis patients. In the CKD population, high serum FGF23 concentration seems to predict the occurrence of refractory secondary hyperparathyroidism, by inducing a resistance of the parathyroid glands to FGF23, and to be associated with higher mortality risk in incident hemodialysis patients. FGF23 appears to be involved in bone metabolism, but a direct effect of FGF23 on bone disease in humans has not yet been elucidated, even if the inhibitory effect of FGF23 on osteoblast activity that has been described in animal models and hereditary rickets is clearly connected with FGF23 deficiency. The association between altered levels of FGF23 and bone disease could be mainly due to the dysregulation of phosphate-handling and vitamin D metabolism, more than to a direct antiosteoblastic activity of FGF23. FGF23 appears to be a new biomarker, which is independently associated with several cardiovascular risk factors such as endothelial dysfunction, arterial stiffness and left ventricular hypertrophy, in the general population as well as in early CKD. All of the above have been related to cardiovascular and general mortality. Until now, we know that elevated FGF23 levels in dialysis patient are associated with several cardiovascular adverse outcomes mentioned above; the clinical relevance of high FGF23 values in dialysis patients remains unclear, because therapy with active vitamin D sterols further increases FGF23 levels but, on the other hand, is associated with a survival benefit in dialysis patients. This paradox highlights the need for future prospective randomized trials to evaluate the correlation between vitamin D therapy and FGF23 levels in dialysis patients. In the clinical setting, there are still different FGF23 actions that need investigation. In this sense, increased knowledge of mineral metabolism disorder alterations in CKD may be used to improve diagnostics and select future treatments
Progetto di recupero e valorizzazione degli ecosistemi del territorio comunale di Finale Emilia
No full textSi studiano le potenzialità di valorizzazione delle risorse ambientali di siti sottoutilizzati nella fascia urbana attorno al centro storico della città di Finale Emilia, assunta come caso di studio ai fini di una progettazione condotta a varie scale
Treatment Failure of Active Vitamin D Therapy in Chronic Kidney Disease : Predictive Factors
No full textIn patients with chronic kidney disease (CKD), impaired renal function leads to decreased vitamin D levels, which causes an increase in parathyroid hormone (PTH) production and contributes to the development of secondary hyperparathyroidism (SHPT). This may result in adverse clinical effects such as bone disorders, vascular calcification, cardiovascular disease, and increased mortality. Current treatment practices and associated outcomes with active vitamin D treatment in patients with CKD were reviewed with the objective to assess parameters (such as PTH and serum calcium levels) that may be used to define the failure of vitamin D treatment
DESIGN OF A RESONANT SOFT SWITCHING POWER SUPPLY FOR STABILIZED DC IMPULSE DELIVERY
No full textThis thesis addresses the issues involved in the design and construction of a multiphase
resonant switching power supply for delivery of a high voltage, high current
stabilized DC impulse. Such a power supply may be used in place a pulse forming
network (PFN) to drive a high power klystron amplifier, which typically requires
voltages near -100kV at 10s of amps of current. Unlike an LC PFN, a switchmode power
supply (SMPS) allows greater control over pulse duration while still allowing generation
of longer duration pulses on the order of 10ms with constant output voltage by use of
feedback regulation.
Specifically, the thesis documents the results from the design of a loosely coupled
boost transformer with a parallel LC resonator on the secondary, a microcontroller based
control system for feedback stabilization and techniques of harmonic mitigation to reduce
switching noise on the output waveform
Intrauterine life to adulthood: a potential risk factor for chronic kidney disease
No full textMultiple risk factors for chronic kidney disease (CKD), one of the major cause of morbidity and mortality in adult population globally, have been identified including older age, male gender, family history, smoking, diabetes mellitus, hypertension, ischemic heart diseases and various medications. Preterm delivery, affecting more than 10% of the newborns in the United States, is a global concern with increasing incidence over the recent decades. Preterm birth has been linked to multiple medical comorbidities such as diabetes mellitus, hypertension and cardiovascular diseases while its' association with CKD has recently been investigated. Prematurity and intrauterine growth restriction (IUGR) have been associated with increased risk for CKD, specific histopathological examination findings, and CKD-associated risk factors such as diabetes mellitus, hypertension and dyslipidaemia. In this narrative review our aim is to evaluate and summarize the association between the risk for CKD and prematurity, low birth weight and IUGR along with potential underlying pathophysiological mechanisms
Bioethik zwischen Natur und Kultur
No full textPossiamo sperare di venire a capo dei principali problemi della bioetica contemporanea solo a condizione di operare una mediazione soddisfacente tra natura e cultura, senza che nessuno dei due termini si riduca all'altro
Outcome of Endovascular Repair of Popliteal Artery Aneurysms using the Supera Stent
No full textPurpose: To evaluate the efficacy of endovascular repair of popliteal artery aneurysms (PAAs) with a wire-interwoven nitinol stent. Materials and Methods: This is a prospective, descriptive, and analytical study. From January 2016 to December 2018, 28 consecutive patients (29 lower limbs) were treated for a PAA with the deployment of the Supera stent (Abbott Vascular, Illinois). Twenty-three (79.3%) PAAs were asymptomatic; 6 (20.7%) presented with symptoms. The mean diameter and length of the aneurysm were 26.8 mm (20–40 mm) and 47.1 mm (23–145 mm) respectively. The primary endpoint was the prevention of embolic symptoms. The secondary endpoints were aneurysm exclusion, aneurysm diameter decrease, freedom from reintervention, and preservation of preoperative runoff vessels. Results: Technical success was 100%, with a median of 2.4 run-off vessels at completion angiography, without any loss of run-off vessels. A double Supera stent was deployed in 10 cases. At completion angiography, a median of 2.4 runoff vessels were present, without any loss of runoff vessels. The mean follow-up time was 24.3 (12–35) months. Primary endpoints were reached in 100% of the cases and vessels run off was preserved in all cases. In 2 PAAs, complete sac thrombosis was witnessed at 6-month follow-up, while at 12-month follow-up, it was seen in 10 of 29 (34.4%) limbs. In all the other cases the diameter of the aneurysm remained stable, with a freedom from sac enlargement of 100%. No fractures or stent thromboses were detected. Conclusions: For endovascular repair of PAAs, the use of a thick interwoven-wire stent, that could work like a multilayer flow modulator showed encouraging mid-term results with no cases of stent fracture, occlusion or aneurysm increase
Endovascular occlusion of an aortic coarctation after thoracic endovascular aortic repair of an anastomotic aneurysm
No full textA 58-year-old man with a history of aortic and mitral mechanical valve replacement was referred to our hospital for symptomatic chronic heart failure. In 1988, he had undergone open surgical correction of an isthmic aortic coarctation (CoA), with the creation of an extra-anatomic bypass from the left subclavian artery to the descending thoracic aorta. The following findings were found: severe mitral valve failure with perivalvular leakage, severe aortic valve stenosis, pulmonary hypertension, distal anastomotic aneurysm with the apparent occlusion of the CoA. A thoracic endovascular aneurysm repair was performed. A postoperative high-pressure leak with no evident signs of ineffective sealing was observed. Computed tomography angiography (CTA) 3D reconstruction demonstrated the recanalization of the CoA. A second procedure was planned. The CoA was anterogradely cannulated. Three coils were deployed into the aneurysmal sac, followed by a vascular plug, positioned on the coarctation conduit, but it failed to anchor and dislocated into the sac. A second plug was deployed, but it also partially dislocated. Finally, a patent foramen ovale occluder device was deployed to occlude the communication. The final angiogram showed the complete occlusion of the coarctation and correction of the leak, which was confirmed by a 6-month post-operative CTA
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