The Role of 3D Printing in Planning Complex Medical Procedures and Training of Medical Professionals-Cross-Sectional Multispecialty Review.

Medicine is a rapidly-evolving discipline, with progress picking up pace with each passing decade. This constant evolution results in the introduction of new tools and methods, which in turn occasionally leads to paradigm shifts across the affected medical fields. The following review attempts to showcase how 3D printing has begun to reshape and improve processes across various medical specialties and where it has the potential to make a significant impact. The current state-of-the-art, as well as real-life clinical applications of 3D printing, are reflected in the perspectives of specialists practicing in the selected disciplines, with a focus on pre-procedural planning, simulation (rehearsal) of non-routine procedures, and on medical education and training. A review of the latest multidisciplinary literature on the subject offers a general summary of the advances enabled by 3D printing. Numerous advantages and applications were found, such as gaining better insight into patient-specific anatomy, better pre-operative planning, mock simulated surgeries, simulation-based training and education, development of surgical guides and other tools, patient-specific implants, bioprinted organs or structures, and counseling of patients. It was evident that pre-procedural planning and rehearsing of unusual or difficult procedures and training of medical professionals in these procedures are extremely useful and transformative.

A non-invasive method to relate the timing of neural activity to white matter microstructural integrity.

The neurophysiological basis of variability in the latency of evoked neural responses has been of interest for decades. We describe a method to identify white matter pathways that may contribute to inter-individual variability in the timing of neural activity. We investigated the relation of the latency of peak visual responses in occipital cortex as measured by magnetoencephalography (MEG) to fractional anisotropy (FA) in the entire brain as measured with diffusion tensor imaging (DTI) in eight healthy young adults. This method makes no assumptions about the anatomy of white matter connections. Visual responses were evoked during a saccadic paradigm and were time-locked to arrival at a saccadic goal. The latency of the peak visual response was inversely related to FA in bilateral parietal and right lateral frontal white matter adjacent to cortical regions that modulate early visual responses. These relations suggest that biophysical properties of white matter affect the timing of early visual responses. This preliminary report demonstrates a non-invasive, unbiased method to relate the timing information from evoked-response experiments to the biophysical properties of white matter measured with DTI.

Where left becomes right: a magnetoencephalographic study of sensorimotor transformation for antisaccades.

To perform a saccadic response to a visual stimulus, a 'sensorimotor transformation' is required (i.e., transforming stimulus location into a motor command). Where in the brain is this accomplished? While previous monkey neurophysiology and human fMRI studies examined either parietal cortex or frontal eye field, we studied both of these regions simultaneously using magnetoencephalography (MEG). Nineteen healthy participants performed a pseudorandom series of prosaccades and antisaccades during MEG. Antisaccades require a saccade in the direction opposite a suddenly appearing stimulus. We exploited this dissociation between stimulus and saccadic direction to identify cortical regions that show early activity for a contralateral stimulus and late activity for a contralateral saccade. We found that in the left hemisphere both the intraparietal sulcus and the frontal eye field showed a pattern of activity consistent with sensorimotor transformation - a transition from activity reflecting the direction of the stimulus to that representing the saccadic goal. These findings suggest that sensorimotor transformation is the product of coordinated activity across the intraparietal sulcus and frontal eye field, key components of a cortical network for saccadic generation.

Covalent binding and interstrand cross-linking of duplex DNA by dirhodium(II,II) carboxylate compounds.

The study of the interactions of double-stranded (ds) DNA with the dirhodium carboxylate compounds Rh(2)(O(2)CCH(3))(4)(H(2)O)(2) (Rh1), [Rh(2)(O(2)CCH(3))(2)(CH(3)CN)(6)](BF(4))(2) (Rh2), and Rh(2)(O(2)CCF(3))(4) (Rh3) supports the presence of covalently linked DNA adducts, including stable DNA interstrand cross-links. The present biochemical study refutes earlier claims that no reaction between dirhodium compounds and dsDNA occurs. The reversal behavior of these interstrand cross-links in 5 M urea at 95 degrees C (for different heating times) implies the presence of various coordination modes involving ax/ax, ax/eq, and eq/eq DNA interactions with the dirhodium core. The reaction rates of the dirhodium compounds with dsDNA were determined spectroscopically and are in the order Rh1 << Rh2 < Rh3. This difference in behavior of the three dirhodium compounds correlates with the lability of the leaving groups and corresponds to the extent of interstrand cross-link formation by these compounds on a 123 bp DNA fragment, as observed by denaturing polyacrylamide gel electrophoresis (dPAGE). Since all three dirhodium compounds form covalent Rh-DNA adducts, including interstrand cross-links, it is important that DNA be considered a potential target for biological activity of these dirhodium carboxylate compounds.