Sensors are being developed that can be implanted in tissues for continuous monitoring of oxygen, glucose, and other metabolites. However, there have been difficulties in inferring metabolite concentrations in blood from the signals of tissue sensors due to the properties of tissues at the implant site and local physiological phenomena that can affect sensor responses. A multisensor array has been previously developed for implantation in a hamster skinfold window chamber preparation to study these effects. The preparation allows recording of concentration-dependent signals from multiple sensors while nondestructively visualizing the adjacent tissue and microvascular function. Variants of the tissue-sensor array window chamber described here have respective advantages over the original chamber design, including improved tissue visualization and reduced surgical intervention, and allow exposure of the sensor to different tissues. Results indicate that mass transfer within tissues is heterogeneous, and sensor signals are affected by variable perfusion of local microvasculature in addition to vascular metabolite concentration. These observations suggest new strategies for sensor design and operation. Window chamber variants are important tools for validation of implanted sensors.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1152/ajpheart.01001.2004 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A domed window chamber for multi-modality optical imaging.
Biotechniques
January 2025
Biomedical Engineering, The University of Arizona, Tucson, AZ, USA.
Current dorsal skin flap window chambers with flat glass windows are compatible with optical coherence tomography (OCT) and multiphoton microscopy (MPM) imaging. However, light sheet fluorescence microscopy (LSFM) performs best with a cylindrical or spherical sample located between its two 90° objectives and when all sample materials have the same index of refraction (). A modified window chamber with a domed viewing window made from fluorinated ethylene propylene (FEP), with n similar to water and tissue, was designed.
View Article and Find Full Text PDFChronic intermittent hypobaric hypoxia alleviates early-stage posttraumatic osteoarthritis via NF-κB/Nrf2 pathway in mice.
J Orthop Surg Res
December 2024
Department of Orthopaedic Trauma, Hebei Medical University Third Hospital, Ziqiang Road No.139, Shijiazhuang, Hebei Province, 050051, China.
Background: Posttraumatic osteoarthritis (PTOA) is directly associated with early acute articular cartilage injury. Inhibition of cartilage destruction immediately following joint damage can effectively slow or prevent PTOA progression. Therefore, we sought to determine intervention targets and therapeutic strategies in the acute stage of cartilage injury.
View Article and Find Full Text PDFFeasibility of volumetric-modulated arc therapy gating for cardiac radioablation using real-time ECG signal acquisition and a dynamic phantom.
Med Phys
December 2024
Department of Physics, The Verspeeten Family Cancer Centre, London, Ontario, Canada.
Background: Stereotactic arrythmia radioablation (STAR) is a noninvasive technique to treat ventricular tachycardia (VT). Management of cardiorespiratory motion plays an essential role in VT-STAR treatments to improve treatment outcomes by reducing positional uncertainties and increasing dose conformality. Use of an electrocardiogram (ECG) signal, acquired in real-time, as a surrogate to gate the beam has the potential to fulfil that intent.
View Article and Find Full Text PDFIntermittent Short Atrioventricular Delay in a Dual Chamber Pacemaker During Acute Pulmonary Edema.
Ann Noninvasive Electrocardiol
January 2025
Cardiovascular Institute-Hospital Clínico San Carlos, Madrid, Spain.
We present the case of an 80-year-old female with acute pulmonary edema and a dual chamber pacemaker with intermittent short AV delays in the surface ECG after blocked premature atrial contractions (PACs). The behavior was consistent with the programmed Window of Atrial Rate Acceleration Detection (WARAD) and did not require further parameter modifications. As most cardiologists and emergency department physicians are not familiar with brand-specific algorithms, we believe that this case report will make these noncompetitive atrial pacing algorithms more accessible to non-cardiologists.
View Article and Find Full Text PDFInvestigating the impact of the effective point of measurement for plane-parallel ionization chambers in clinical proton beams.
Phys Med Biol
December 2024
National Physical Laboratory, Teddington, United Kingdom.
Article Synopsis
- This study examines how the placement of plane-parallel ionization chambers affects the calculation of specific factors and beam quality correction factors in proton beams.
- Monte Carlo simulations were used to analyze six ionization chamber types with different positioning methods, showing significant differences, especially in areas with steep dose gradients.
- The findings indicate that using the effective point of measurement as recommended by the updated TRS-398 code may introduce systematic errors in the correction factors for these chambers, potentially impacting dosimetry accuracy.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!