We developed a quartz crystal biosensor designed to detect concentrations and ligand affinity parameters of free unlabeled proteins in real time. Using a model system with human IgE as the analyte and single-stranded DNA aptamers or an anti-IgE antibody as immobilized ligands, we could demonstrate that aptamers were equivalent to antibodies in terms of specificity and sensitivity. Both receptor types selectively detected 0.5 nmol/L of IgE. In addition, the aptamer receptors tolerated repeated affine layer regeneration after ligand binding and recycling of the biosensor with little loss of sensitivity. Because of the small size and nonprotein nature of the aptamers, they were immobilized in a dense, well-oriented manner, thus extending the linear detection range to 10-fold higher concentrations of IgE. In addition to demonstrating for the first time that an aptamer-based biosensor can specifically and quantitatively detect an analyte in various complex protein mixes, the aptamer-ligand proved to be relatively heat resistant and stable over several weeks. Since aptamers consist of nucleic acids, well-established chemistry can be applied to produce optimized affine layers on biosensors that may be developed to specifically detect proteins in solution for analysis of proteomes.

Diffusion weighted imaging (DWI) has been at the forefront of cancer imaging since the early 2000’s. Prior to its application in clinical oncology, this powerful technique had already achieved widespread recognition due to its utility in the diagnosis of cerebral infarction. Following this initial success, the ability of DWI to detect inherent tissue contrast began to be exploited in the field of oncology. Although the initial oncologic applications for tumor detection and characterization, assessing treatment response, and predicting survival were primarily in the field of neuro-oncology, the scope of DWI has since broadened to include oncologic imaging of the prostate gland, breast, and liver. Despite its growing success and application, misconceptions as to the underlying physical basis of the DWI signal exist among researchers and clinicians alike. In this review, we provide a detailed explanation of the biophysical basis of diffusion contrast, emphasizing the difference between hindered and restricted diffusion, and elucidating how diffusion parameters in tissue are derived from the measurements via the diffusion model. We describe one advanced DWI modeling technique, called Restriction Spectrum Imaging (RSI). This technique offers a more direct in vivo measure of tumor cells, due to its ability to distinguish separable pools of water within tissue based on their intrinsic diffusion characteristics. Using RSI as an example, we then highlight the ability of advanced DWI techniques to address key clinical challenges in neuro-oncology, including improved tumor conspicuity, distinguishing actual response to therapy from pseudoresponse, and delineation of white matter tracts in regions of peritumoral edema. We also discuss how RSI, combined with new methods for correction of spatial distortions inherent diffusion MRI scans, may enable more precise spatial targeting of lesions, with implications for radiation oncology, and surgical planning.

This white paper provides a concise reference document for the more common prostate biopsy complications and prevention strategies. Risk assessment should be performed for all patients to identify known risk factors for harboring fluoroquinolone resistance. If infection incidence increases check the local antibiogram, current equipment and cleaning practices, and consider alternate approaches to antibiotic prevention such as needle cleaning, risk basked augmentation, rectal culture with targeted prophylaxis and transperineal biopsy. If infection occurs, actively re-situate the patient and start empiric intravenous treatment with carbapenems, amikacin or second and third generation cephalosporins.

A contemporary risk tool for outcomes on prostate biopsy based on the routine clinical risk factors is now available for informed decision-making.