Comparison of three different preparations of platelet concentrates for growth factor enrichment.

The aim of the present study was to compare three different systems for preparing platelet concentrates: two commercially available bed-side techniques (Curasan system and PCCS) and a procedure used routinely in transfusion medicine. Platelet concentrates were prepared from venous blood of 12 healthy male volunteers using the three different systems. Platelet and leucocyte counts were performed and platelet derived growth factor and transforming growth factor beta were assayed by enzyme linked immunoassay. Handling was also considered. The three systems were able to collect 19.0 +/- 16.6% (laboratory system), 41.9 +/- 9.7% (Curasan system) and 49.6 +/- 21.0% (PCCS) of the absolute number of platelets which were originally in the venous blood volume within the platelet concentrate. Due to the amount of plasma which is left in the platelet concentrate portion, the platelet concentration could be increased between 1.4 +/- 1.3 times (laboratory system), 5.0 +/- 2.3 times (PCCS) and 11.7 +/- 2.4 times (Curasan system) compared to the venous blood. The amount of growth factors correlated with the number of platelets within the platelet concentrates. The two systems for intraoperative use are similar in their effects on the platelets. The absolute gain of platelets seems to be the highest with the PCCS; the highest concentration of platelets per micro L is gained with the Curasan system. The laboratory system may offer an alternative if an intraoperative system is not available.

Solid-state nuclear magnetic resonance microscopy demonstrating human dental anatomy.

OBJECTIVE: Magnetic resonance imaging has become a common diagnostic tool in medical practice. It is a common view that solid-state material lacking a sufficient amount of unpaired nuclear spins, in particular proton spins, is impossible to depict with clinically used magnetic resonance devices. Characteristically rapid dephasing, caused by relatively short spin-spin relaxation (T(2) time) also leads to broad resonance lines. A newly introduced technique, constant-time imaging, uses 3 phase-encoding gradients for the acquisition of only one complex data point per phase-encoding step, resulting in detection times of only a few microseconds and extremely sharp resonance lines. STUDY DESIGN: Using a Bruker spectrometer AMX 300 WB (300 MHz, 7.1 T) with a microimaging attachment, we performed solid-state magnetic resonance imaging of whole teeth. Data processing was carried out by means of 3-dimensional Fourier analysis, and reconstructions were performed by the ParaVision (Bruker) software system. RESULTS: Dental hard tissues (enamel, dentin, and root cementum) and pulpal soft tissue could be depicted in 2-dimensional and 3-dimensional images. The voxel resolution isotropically reached 195 microm. CONCLUSION: The constant-time imaging technique enabled a naturalistic and nondestructive visualization of the teeth without application of ionizing radiation. This technique bears the potential to help us overcome the limitations of clinically used standard magnetic resonance tomography devices and offers new perspectives for dental imaging.