Publications by authors named "John W Kakareka"
Article Synopsis
- Researchers developed a new method to effectively measure left ventricular contractility and compliance using pressure-volume loops during dynamic preload reduction, combining cardiovascular magnetic resonance (CMR) imaging and invasive pressure measurements.
- In a study with 16 swine, various models (including ones with aortic banding and ischemic cardiomyopathy) were used to evaluate changes in contractility and compliance through dynamic occlusion of the inferior vena cava.
- Results showed that animals with ischemic cardiomyopathy had significantly lower contractility and increased compliance compared to naïve swine, while measurements from CMR and traditional catheter techniques demonstrated good agreement.
Article Synopsis
- The study focuses on the use of 3D-printed centerpieces for analytical ultracentrifugation, highlighting their ability to hold samples while enabling accurate macromolecular migration under high centrifugal forces.
- Researchers demonstrate that these 3D-printed centerpieces are durable, reusable, and can produce data comparable to traditional epoxy resin centerpieces, making them a cost-effective alternative.
- The paper introduces innovative centerpiece designs that improve experimental efficiency, such as designs that reduce sample volume, minimize optical aberrations, and increase sample capacity, all while maintaining high-quality results.
Article Synopsis
- * The Hand-Arm Movement Monitoring System (HAMMS) is a new, video-based system developed to assess hand and arm movement metrics through a targeted motion test in older adults.
- * Initial validation shows that HAMMS has good reliability and indicates that as age increases, hand-arm movement control declines, making it a promising tool for tracking neurological disease progression.
Article Synopsis
- The paper discusses the importance of hemodynamic recording during interventional cardiovascular procedures and the challenges posed by electromagnetic interference (EMI) in MRI environments.
- It outlines the development of a new system designed to minimize EMI effects on electrocardiogram (ECG) and invasive blood pressure (IBP) signals using MRI-compatible equipment and adaptive signal processing techniques.
- Results showed an impressive 80% reduction in peak noise and the elimination of false QRS triggers during real-time MRI scanning in pediatric patients, paving the way for better high-fidelity recordings in MRI-guided procedures.
Article Synopsis
- Sentinel lymph node biopsy is a common procedure in breast cancer surgery, and there's a need for quicker methods to identify cancer spread.
- A new fluorescent method was tested, using a dye to identify breast cancer cells in lymph nodes from 38 patients, showing promising results.
- The method demonstrated high sensitivity (97%), good specificity (79%), and an excellent negative predictive value (99%), indicating it could help surgeons make faster and more accurate decisions during operations.
Article Synopsis
- Stray light, which does not pass through a sample in spectroscopy, causes a phenomenon called absorption flattening that distorts the resulting spectrum.
- Scientists must either account for stray light (leading to inaccurate spectra) or mask parts of the crystal to avoid this issue.
- The paper introduces a new method that enables the use of the entire crystal while correcting for the distortion in the spectrum caused by stray light.
Article Synopsis
- Researchers developed gGlu-HMRG as a fluorescent probe to detect live cancer cells by utilizing the overexpression of the enzyme GGT in cancer versus normal tissue.
- In a study, they tested this probe during breast-conserving surgery and found it could distinguish tumors as small as 1 mm with 92% sensitivity and 94% specificity in just 5 minutes.
- The method is considered a significant advancement in quickly and affordably assessing surgical margins to ensure all cancerous tissue is removed.
Article Synopsis
- A prototype positron projection imager (PPI) was developed to visualize the biodistribution of positron-emitting compounds in small animals, particularly mice, and will be integrated into a dual-gamma camera system for flexible imaging options.
- The imaging setup involves placing a mouse between two identical LYSO arrays to record positron-decay events, with performance tested using various positron-emitting compounds.
- Performance results showed good imaging quality, with clear visualization of compounds like [(18)F] FDG, suggesting the PPI's potential utility in early drug development stages by providing essential biodistribution data.
Article Synopsis
- * Our recent study further explored the conformational changes during the photocycle using amide spectral envelopes to gather quantitative data.
- * A key finding highlights significant changes when transitioning from the M(F) intermediate to N, and we present support for a newly identified proton acceptor related to the transformation of BR† to L.
Article Synopsis
- * This approach allowed us to separate the M intermediate into its M(F) and M(S) components and compute detailed IR difference spectra, providing a rigorous analysis of the photocycle steps.
- * We identified a significant new IR band at 1650 cm(-1) for the L intermediate at room temperature, which had not been observed in previous studies, and concluded that Arg82 is the key proton-release group during the photocycle.
Article Synopsis
- The study aims to address challenges in testing novel optical probes on human specimens in the operating room, where tissue removal poses regulatory and privacy issues.
- A portable benchtop fluorescence camera was developed and tested using a mouse model of ovarian cancer, demonstrating its effectiveness against standard imaging systems.
- The results indicate that the compact camera can successfully produce comparable imaging, allowing for immediate testing of excised tissues in the operating room, which could speed up the development of new imaging probes.
Article Synopsis
- A new portable dual-gamma camera system called "MONICA" is designed for visualizing and analyzing the distribution of radiotracers in small animals, particularly mice.
- The system features two miniature gamma cameras that allow for direct imaging of the mice placed on a tabletop, and its performance was validated through testing and a detailed study over a week.
- Results indicate that MONICA is effective for whole-body imaging in mice, which may aid early drug development by providing crucial biodistribution data in a space-efficient manner.
Article Synopsis
- A unique high-speed optical multichannel spectrometer was created at NIH and detailed in a 1997 journal article, allowing researchers to track entire time courses using a single sample.
- It has been utilized to explore rapid kinetic processes like the bacteriorhodopsin photocycle and electron transport in cellular respiration.
- The latest version features significant improvements for kinetic studies, showcased by measuring proton flow alongside optical steps of the photocycle to link molecular changes to proton movements.