Individualized 3D-printed templates for high-dose-rate interstitial multicathether brachytherapy in patients with breast cancer

Purpose

High-dose-rate, multicatheter interstitial brachytherapy is technically complex and operator-dependent, requiring lengthy training and specialized skills. Furthermore, until the advent of contouring on computerized tomography (CT) images, difficulties existed in locating the target volume precisely. The present article reports the results of a study that aimed at producing and validating a 3D-printed template to aid in target volume localization for multicatheter interstitial brachytherapy in patients with breast cancer.

Intracardiac flow analysis in cardiac resynchronization therapy: A new challenge?

In the past years, assessment of cardiac function has become possible through the analysis of intracardiac flow dynamics, performed noninvasively using phase‐contrast cardiac magnetic resonance and contrast and noncontrast ultrasound techniques. From 2013 to 2019, 9 echocardiographic investigations have considered 215 patients with cardiac resynchronization therapy (CRT) as a model for assessing flow dynamics within the left ventricle. Preliminary results have been reported about the acute hemodynamic effects of CRT and programming of the CRT device, showing the potential of an approach based on analysis of intracardiac flows. At present, there are only scarce data on the capability of intracardiac flow dynamics to predict LV remodeling after CRT and no information on clinical outcome prediction. Future investigations should be aimed at clarifying the mechanisms and impact of maladaptive intracardiac vortex dynamics on progressive LV remodeling as well as the prognostic meaning of implanted CRT device based on cardiac flow analysis.     

Disruption of neonatal Purkinje cell function underlies injury-related learning deficits

It is hypothesized that perinatal cerebellar injury leads to long-term functional deficits due to circuit dysmaturation. Using a novel integration of GCaMP6f fiber photometry with automated measurement of cerebellar behavior using the ErasmusLadder, we causally link cerebellar injury to altered Purkinje cell responses during maladaptive behavior. Chemogenetic inhibition of neonatal Purkinje cells is sufficient to phenocopy the effects of perinatal cerebellar injury. Our results uncover a direct link between perinatal cerebellar injury and activity-dependent maturation of cerebellar cortex.

Perinatal complications of preterm or term neonates often result in adaptive behavioral deficits. While injury to the developing cerebellum has been correlated to long-term behavioral abnormalities, especially in locomotor function, the specific neural circuits and physiological mechanisms that are disrupted are unknown. Recent work characterized the spatial and temporal components of interlimb coordination in cerebellum-dependent locomotor learning (1). However, the sparsity of techniques available to directly measure neuronal activity during adaptive cerebellar behavior hampers efforts to identify the functional and mechanistic basis of behavioral pathology.We designed a unique method to measure Purkinje cell (PC) activity during an adaptive cerebellum-dependent locomotor learning task. We utilized the ErasmusLadder––an automated behavioral system that can accurately quantify cerebellum-dependent locomotor learning and adaptive behavior. The ErasmusLadder enables the use of an associative conditioned-learning paradigm that is temporally tuned to define cerebellum-specific aspects of motor learning over multiple trials (2, 3). By directly integrating fiber photometry of the genetically encoded Ca²⁺ indicator—GCaMP6f—with the ErasmusLadder, we successfully and simultaneously recorded population responses of PCs in mice in real time during unrestrained behavior on the ErasmusLadder. We used our method to integrate PC activity measurement with adaptive behavioral quantification to identify a mechanistic basis for locomotor learning dysfunction in a clinically relevant mouse model of neonatal brain injury (4).