Aragonite crystals grown on bones by reaction of CO2 with nanostructured Ca(OH)2 in the presence of collagen. Implications in archaeology and paleontology.

The loss of mechanical properties affecting archeological or paleontological bones is often caused by demineralization processes that are similar to those driving the mechanisms leading to osteoporosis. One simple way to harden and to strengthen demineralized bone remains could be the in situ growth of CaCO3 crystals in the aragonite polymorph - metastable at atmospheric pressure -which is known to have very strong mechanical strength in comparison with the stable calcite. In the present study the controlled growth of aragonite crystals was achieved by reaction between atmospheric CO2 and calcium hydroxide nanoparticles in the presence of collagen within the deteriorated bones. In a few days the carbonation of Ca(OH)2 particles led to a mixture of calcite and aragonite, increasing the strength of the mineral network of the bone. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and Fourier transform infrared (FT-IR) spectrometry showed that aragonite crystallization was achieved. The effect of the aragonite crystal formation on the mechanical properties of the deteriorated bones was investigated by means of X-rays microtomography, helium porosimetry, atomic force microscopy (AFM), and Vickers microhardness techniques. All these data enabled to conclude that the strength of the bones increased of a factor of 50-70% with respect to the untreated bone. These results could have immediate impact for preserving archeological and paleontological bone remains.

Second-opinion stress tele-echocardiography for the Adonhers (Aged donor heart rescue by stress echo) project.

BACKGROUND: To resolve the current shortage of donor hearts, we established the Adonhers protocol. An upward shift of the donor age cut-off limit (from the present 55 to 65 years) is acceptable if a stress echo screening on the candidate donor heart is normal. This study aimed to verify feasibility of a "second opinion" of digitally transferred images of stress echo results to minimize technical variability in selection of aged donor hearts for heart transplant. METHODS: The informatics infrastructure was created for a core lab reading with a second opinion from the Pisa stress echo lab. To test the system, simulation standard stress echo cineloops were sent digitally from 5 peripheral labs to the central core lab.Starting January 2009, real marginal donor stress echos were sent via internet to the central core echo lab, Pisa, for a second opinion before heart transplant. RESULTS: In the simulation protocol, 30 dipyridamole stress echocardiograms were sent from the five peripheral echo labs to the central core lab in Pisa. Both the echo images and reports were correctly uploaded in the web system and sent to the core echo lab; the second opinion evaluation was obtained in all cases (100% feasibility). In the transplant protocol, eight donor cases were sent to the Pisa core lab for the second opinion protocol, and six of them were transplanted in marginal recipients. CONCLUSIONS: Second-Opinion Stress Tele-Echocardiography can effectively be performed in a network aimed to safely expand the heart donor pool for heart transplant.

Right ventricular presystolic peak velocity represents right ventricular function in stable patients.

BACKGROUND: Right ventricular (RV) function is difficult to be measured but plays a role in morbility and mortality of patients with cardiopulmonary diseases, so many echocardiographic parameters have been developed from M-mode, B-mode and Doppler tissue imaging (DTI) evaluation. Right ventricular presystolic peak velocity (RVPrP) measured with DTI of the tricuspidal annulus and its changes in RV dysfunction have never been assessed in a patient's cohort of stable patients with cardiovascular risk factors. RVPrP velocity could have a role in RV function evaluation; this study addresses such issue. METHODS: Four hundred thirty-six consecutive patients were submitted to a complete echocardiographic examination with the contemporary evaluation of the following RV function indexes: Tricuspid Annulus Plane Systolic Excurtion (TAPSE), RV Systolic Peak (RVSyP) and RVPrP. Pulmonary artery systolic pressure (PASP), left ventricular and RV diastolic function were also evaluated. RESULTS: According to TAPSE and RVSyP taken alone or in combination, 113 patients had RV dysfunction, while 323 patients had normal RV function. RVPrP was reduced in patient's group with RV dysfunction with respect to patient's group with preserved RV function (16.48±7.3 cm/s vs. 23.98±8.4 cm/s, respectively, P<0.001). RVPrP was related with RVSyP (P<0.001) and with TAPSE (P=0.002). TAPSE and RVSyP revealed a poor concordance to define RV dysfunction. PASP was higher in patient's group with reduced RV function (P=0.033). CONCLUSIONS: The study showed RVPrP able to detect stable patients with RV dysfunction.