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SummaryThis paper reports our personal experience filling the gap regarding changes of bone mineral density after surgical treatment in patient suffering from tumor-induced osteomalacia.IntroductionNo systematic data are available regarding long-term bone mineral density (BMD) changes after surgical cure of patients with tumor-induced osteomalacia.MethodsFrom October 2001 through April 2018, we studied 10 consecutive patients (mean age ± SD, 45.5 ± 13.8 years; 5 males and 5 females) with tumor-induced osteomalacia. We evaluated BMD when initially presented at our Center and after surgical removal of the tumor.ResultsBasal BMD and corresponding Z-score values (mean values ± SD) measured by DXA were as follows: L1–L4 = 0.692 ± 0.15 g/cm2, Z-score = − 2.80 ± 1.60; femur neck 0.447 ± 0.10 g/cm2, Z-score = − 2.66 ± 0.93; total femur = 0.450 ± 0.08 g/cm2, Z-score = −3.04 ± 0.85). Furthermore, Trabecular Bone Score (TBS) was evaluated in three patients (basal values, 0.990 ± 0.32). Seven patients were intermittently followed after surgical excision of the tumor while supplemented with cholecalciferol and calcium salts; the remaining three were lost to follow-up. There was a striking increase of BMD values that peaked at 26.7 ± 6.50 months: L1–L4 = 1.289 ± 0.247 g/cm2, p < 0.001, Z-score + 1.75 ± 1.42; femur neck = 0.890 ± 0.235 g/cm2, p = 0.028, Z-score = + 0.50 ± 1.40; total femur = 0.834 ± 0.150 g/cm2, p = 0.005, Z-score = − 0.74 ± 1.14. In patients with the greatest bone involvement at lumbar site, there was a striking increase of an average 1.5% (p < 0.01) in respect to baseline Z-score value for each additional month of observation during the first 2–3 years post-surgery. An improvement of trabecular microarchitecture was also documented (TBS, 1.255 ± 0.16).ConclusionThis is the first case series documenting an impressive increase of BMD at both lumbar and femoral sites, together with an improvement of trabecular microarchitecture as documented by TBS. This is the consequence of huge mineralization of the large amount of osteoid tissue after resolution of the disease.

Purpose To investigate the occurrence of arrhythmias in patients with normocalcemic (NC) primary hyperparathyroidism (PHPT) compared to both hypercalcemic PHPT patients and control subjects by means of 24-h Holter ECG. Methods Thirteen NCPHPT postmenopausal patients were enrolled and age-matched with 13 hypercalcemic PHPT patients and 13 controls. Every subject underwent basal ECG, 24-h Holter ECG and mineral metabolism biochemical evaluation. Results PHPT patients had higher mean serum calcium levels compared to both NCPHPT and controls; there was no difference in mean serum calcium levels between NCPHPT and controls. Both NCPHPT and PHPT patients had significantly higher mean PTH levels compared with controls. There were no differences in ECG parameters between the three groups, except for QTc interval. PHPT patients had normal QTc interval values, but significantly shorter mean values compared with those of controls and NCPHPT patients. During 24-h Holter ECG recording, 100% of PHPT patients had supraventricular premature beats (SVPBs), compared to 46% of NCPHPT ( p  = 0.005) and to 53% of controls ( p  = 0.01). PHPT patients experienced ventricular premature beats (VPBs) (69.2%) vs 15% of NCPHPT patients ( p  = 0.01) and 23% of controls ( p  = 0.04). There was no difference between NCPHPT and controls subjects concerning occurrence of both VPBs and SVPBs. Conclusions NCPHPT patients did not experience an increased occurrence of arrhythmias compared to controls, while PHPT patients showed an increased occurrence compared to both controls and NCPHPT. Our findings are most probably related to the short QTc interval caused by hypercalcemia observed in PHPT patients, but not in NCPHPT.

SummaryThe only difference between fractured and non-fractured postmenopausal women with PHPT of same sex, age, and BMI was a significantly mean higher serum k-periostin level. K-periostin value was associated with fracture at any site (odds ratio 1.044, 95% CI 1.005–1.091, p = 0.03).IntroductionTo assess serum k-periostin fragment levels in patients with primary hyperparathyroidism (PHPT), fractured and non-fractured matched for sex, age, and body mass index.MethodsTwenty-five Caucasian fractured postmenopausal women with PHPT (group Fx) and 25 PHPT non-fractured (group NFx) were enrolled. Each patient underwent DXA scan at lumbar, hip, and forearm, spine X-ray, and biochemical evaluation of calcium metabolism. For k-periostin analyses, we utilized a specific ELISA test that detects CatK-generated fragment levels in the bloodstream.ResultsWe found no difference in mean BMD and bone turnover marker values between Fx and NFx groups. Prevalence of osteoporosis was not significantly different in Fx vs NFx (72% vs 60%, p = 0.55). Among Fx, 16% reported multiple fractures, 28% morphometric vertebral fractures, 4% femoral fractures, 28% non-vertebral non-femoral fractures, and 8% wrist fractures. The only detectable difference between Fx and NFx group was a significantly mean higher k-periostin serum level (46.2 ± 21.4 vs 34.7 ± 13.5 ng/ml, p = 0.02). K-periostin was associated with fracture at any site (odds ratio 1.044, 95% CI 1.005–1.091, p = 0.03). No difference in mean k-periostin values was found between patients with vertebral fracture vs those with non-vertebral fracture, and between those with multiple fractures vs those with single fracture.ConclusionSerum k-periostin is significantly associated with fracture in PHPT. If confirmed by further studies, k-periostin could be considered a new marker of bone fragility in PHPT, independently of BMD.

We investigated the usefulness of fibroblast growth factor 23 (FGF23) intraoperative assay to monitor tumor resection in patients with oncogenic osteomalacia. A 33-year-old man with 5 years’ history of lumbar and pelvis pain together with multiple vertebral fractures was admitted to our hospital. He was diagnosed with ankylosing spondylitis 1 year before. Laboratory investigation showed low tubular reabsorption of phosphate (0.41 mmol/L) despite chronic hypophosphatemia (0.39/L). Increased plasma values of FGF23 (673 pg/mL; n.v. < 95 pg/mL) were also observed. A full-body CT scan showed two suspicious areas in the head of the right femur and in the right tibia; however, the Octreoscan™ showed an increased uptake of the tracer only in the femur. We decided to remove first the head femur lesion and perform intraoperative FGF23 assay to confirm tumor resection; if this had been unsuccessful, we would have extended the operation to excise the second bone lesion. FGF23 basal values and 10, 60, and 225 min after excision of the femoral head were 423, 127, 56, and 30 pg/mL, respectively. The brisk fall of FGF23 values suggested that the head femur lesion was responsible for the syndrome. Histological examination revealed a mesenchymal highly vascular tumor. This is the first report showing the possibility of intraoperative FGF23 assay to monitor tumor resection in patients with tumor-induced osteomalacia.

A reversed-field pinch is a toroidal device for magnetically confining plasmas, and a potential alternative to the tokamak for a future fusion reactor. Observations of the evolution of a reversed-field-pinch plasma towards a self-organized single-helicity state suggest that instability problems, which have previously hindered the development of these devices, could now be overcome. In the quest for new energy sources, the research on controlled thermonuclear fusion 1 has been boosted by the start of the construction phase of the International Thermonuclear Experimental Reactor 2 (ITER). ITER is based on the tokamak magnetic configuration 3 , which is the best performing one in terms of energy confinement. Alternative concepts are however actively researched, which in the long term could be considered for a second generation of reactors. Here, we show results concerning one of these configurations, the reversed-field pinch 4 , 5 (RFP). By increasing the plasma current, a spontaneous transition to a helical equilibrium occurs, with a change of magnetic topology. Partially conserved magnetic flux surfaces emerge within residual magnetic chaos, resulting in the onset of a transport barrier. This is a structural change and sheds new light on the potential of the RFP as the basis for a low-magnetic-field ohmic fusion reactor.

The experimental fusion reactor ITER will feature two (or three) heating neutral beam injectors (NBI) capable of delivering 33(or 50) MW of power into the plasma. A NBI consists of a plasma source for production of negative ions (extracted negative ion current up to 329 A/m 2 in H and 285 A/m 2 in D) then accelerated up to 1 MeV for one hour. The negative ion beam is neutralized, and the residual ions are electrostatically removed before injection. The beamline was designed for a beam divergence between 3 and 7 mrad. The ion source in ITER NBIs relies on RF-driven, Inductively-Coupled Plasmas (ICP), based on the prototypes developed at IPP Garching; RF-driven negative-ion beam sources have never been employed in fusion devices up to now. The recent results of SPIDER, the full size ITER NBI ion source operating at NBTF in Consorzio RFX, Padova, measure a beamlet divergence minimum of 12mrad and highlighted beam spatial non-uniformity. SPIDER results confirmed the experimental divergence found in smaller prototype sources, which is larger compared to filament-arc ion sources. Although prototype experiments have shown that the extracted current requirement can be achieved with minor design improvements, the beamlet divergence is expected to marginally achieve the design value of 7 mrad, which in multi-grid long accelerators results in unexpected heat loads over the accelerator grids. A contributor to the beam divergence is the energy/temperature of the extracted negative ions, so it is believed that plasma differences between the two source types play a role. Research is focused on the plasma parameters in the ion source. One RF driver, identical to the ones used in SPIDER, installed in a relatively small-scale experimental set-up, inherently more flexible than large devices, is starting operations devoted to the investigation of the properties of RF-generated plasmas, so as to contribute to the assessment of negative ion precursors, and of their relationship with the plasma parameters, particularly when enhancing plasma confinement. The scientific questions, that have arisen from the preliminary results of SPIDER, guided the design of the test stand, which are described in this contribution, together with the diagnostic systems and related simulation tools. The test stand, which shares with the larger experiment all the geometrical features and constraints, will allow technological developments and optimized engineering solutions related to the ICP design for the ITER NBIs.