Monitoring Of Physiological Changes Research Articles

Interactive Multi-Stage Robotic Positioner for Intra-Operative MRI-Guided Stereotactic Neurosurgery.

Magnetic resonance imaging (MRI) demonstrates clear advantages over other imaging modalities in neurosurgery with its ability to delineate critical neurovascular structures and cancerous tissue in high-resolution 3D anatomical roadmaps. However, its application has been limited to interventions performed based on static pre/post-operative imaging, where errors accrue from stereotactic frame setup, image registration, and brain shift. To leverage the powerful intra-operative functions of MRI, e.g., instrument tracking, monitoring of physiological changes and tissue temperature in MRI-guided bilateral stereotactic neurosurgery, a multi-stage robotic positioner is proposed. The system positions cannula/needle instruments using a lightweight (203g) and compact (Ø97×81mm) skull-mounted structure that fits within most standard imaging head coils. With optimized design in soft robotics, the system operates in two stages: i) manual coarse adjustment performed interactively by the surgeon (workspace of ±30°), ii) automatic fine adjustment with precise (<0.2° orientation error), responsive (1.4Hz bandwidth), and high-resolution (0.058°) soft robotic positioning. Orientation locking provides sufficient transmission stiffness (4.07N/mm) for instrument advancement. The system's clinical workflow and accuracy is validated with lab-based (<0.8mm) and MRI-based testing on skull phantoms (<1.7mm) and a cadaver subject (<2.2mm). Custom-made wireless omni-directional tracking markers facilitated robot registration under MRI.

Use of atomic force microscopy for characterization of model membranes and cells

Background: To provide a fundamental understanding of the potential and use of atomic force microscopy (AFM) in medicine and the life sciences, this work presents a thorough description of imaging and non-imaging atomic force microscopy modes for characterizing model membranes and cells at the nanoscale. Methods: The imaging and non-imaging AFM modes are described with examples in terms of the characterization of topographic, morphological, and nanomechanical sample properties. Results: AFM imaging of supported lipid bilayers (SLBs) revealed the effects of temperature and medium composition on SLB topography in the gel and fluid phases, and on the bilayer thickness. Non-imaging AFM showed the strengthening of the SLB in both phases by the ion binding process.Imaging of neuronal and neuroblastoma cells with and without treatment revealed morphological changes in shape, volume, roughness, and Feret dimension. Non-imaging AFM showed the change in cell elasticity induced by the treatment with H2O2 with and without quercetin and by the treatment with copper and myricetin. The measurements of cells elasticity revealed a reorganization of the cytoskeleton and filament structures. Conclusions: Diverse applications of imaging and non-imaging AFM can provide important information about the underlying processes in biologically relevant systems. AFM, as a complementary technique to other biomedical methods, allows screening and monitoring of physiological changes at the nanoscale.

Explainable machine learning framework to predict personalized physiological aging.

Attaining personalized healthy aging requires accurate monitoring of physiological changes and identifying subclinical markers that predict accelerated or delayed aging. Classic biostatistical methods most rely on supervised variables to estimate physiological aging and do not capture the full complexity of inter-parameter interactions. Machine learning (ML) is promising, but its black box nature eludes direct understanding, substantially limiting physician confidence and clinical usage. Using a broad population dataset from the National Health and Nutrition Examination Survey (NHANES) study including routine biological variables and after selection of XGBoost as the most appropriate algorithm, we created an innovative explainable ML framework to determine a Personalized physiological age (PPA). PPA predicted both chronic disease and mortality independently of chronological age. Twenty-six variables were sufficient to predict PPA. Using SHapley Additive exPlanations (SHAP), we implemented a precise quantitative associated metric for each variable explaining physiological (i.e., accelerated or delayed) deviations from age-specific normative data. Among the variables, glycated hemoglobin (HbA1c) displays a major relative weight in the estimation of PPA. Finally, clustering profiles of identical contextualized explanations reveal different aging trajectories opening opportunities to specific clinical follow-up. These data show that PPA is a robust, quantitative and explainable ML-based metric that monitors personalized health status. Our approach also provides a complete framework applicable to different datasets or variables, allowing precision physiological age estimation.

Stretchable Temperature-Responsive Multimodal Neuromorphic Electronic Skin with Spontaneous Synaptic Plasticity Recovery.

Multimodal electronic skin devices capable of detecting multimodal signals provide the possibility for health monitoring. Sensing and memory for temperature and deformation by human skin are of great significance for the perception and monitoring of physiological changes of the human body. Electronic skin is highly expected to have similar functions as human skin. Here, by implementing intrinsically stretchable neuromorphic transistors with mechanoreceptors and thermoreceptors in an array, we have realized stretchable temperature-responsive multimodal neuromorphic electronic skin (STRM-NES) with both sensory and memory functions, in which synaptic plasticity can be modulated by multiple modalities, in situ temperature variations, and stretching deformations. Temperature-responsive functions, spontaneous recovery, and temperature-dependent multitrial learning are proposed. Furthermore, a stretchable temperature neuromorphic array composed of multiple fully functional subcells is demonstrated to identify temperature distributions and variations at different regions and conditions after various strains of skin. The STRM-NES has temperature- and strain-responsive neuromorphic functions, excellent self-healing, and reusable capability, showing similar abilities as human skin to sense, transmit, memory, and recovery from external stimuli. It is expected to facilitate the development of wearable electronics, intelligent robotics, and prosthetic applications.

Cherenkov emissions for studying tumor changes during radiation therapy: An exploratory study in domesticated dogs with naturally-occurring cancer.

PurposeReal-time monitoring of physiological changes of tumor tissue during radiation therapy (RT) could improve therapeutic efficacy and predict therapeutic outcomes. Cherenkov radiation is a normal byproduct of radiation deposited in tissue. Previous studies in rat tumors have confirmed a correlation between Cherenkov emission spectra and optical measurements of blood-oxygen saturation based on the tissue absorption coefficients. The purpose of this study is to determine if it is feasible to image Cherenkov emissions during radiation therapy in larger human-sized tumors of pet dogs with cancer. We also wished to validate the prior work in rats, to determine if Cherenkov emissions have the potential to act an indicator of blood-oxygen saturation or water-content changes in the tumor tissue–both of which have been correlated with patient prognosis.MethodsA DoseOptics camera, built to image the low-intensity emission of Cherenkov radiation, was used to measure Cherenkov intensities in a cohort of cancer-bearing pet dogs during clinical irradiation. Tumor type and location varied, as did the radiation fractionation scheme and beam arrangement, each planned according to institutional standard-of-care. Unmodulated radiation was delivered using multiple 6 MV X-ray beams from a clinical linear accelerator. Each dog was treated with a minimum of 16 Gy total, in ≥3 fractions. Each fraction was split into at least three subfractions per gantry angle. During each subfraction, Cherenkov emissions were imaged.ResultsWe documented significant intra-subfraction differences between the Cherenkov intensities for normal tissue, whole-tumor tissue, tissue at the edge of the tumor and tissue at the center of the tumor (p<0.05). Additionally, intra-subfraction changes suggest that Cherenkov emissions may have captured fluctuating absorption properties within the tumor.ConclusionHere we demonstrate that it is possible to obtain Cherenkov emissions from canine cancers within a fraction of radiotherapy. The entire optical spectrum was obtained which includes the window for imaging changes in water and hemoglobin saturation. This lends credence to the goal of using this method during radiotherapy in human patients and client-owned pets.

Suitability of diffusion approximation for an inverse analysis of diffuse reflectance spectra from human skin in vivo

Diffusion approximation (DA) of the radiative transport equation allows derivation of enclosed solutions for diffuse reflectance from multi-layer scattering structures, such as human skin. Although the DA is known to be inadequate near tissue boundaries and light sources, analytical tractability makes such solutions very attractive for use in noninvasive characterization of biological organs based on measured diffuse reflectance spectra (DRS). For the presented three-layer model of human skin, which enables a good match with DRS in visible spectral range measured with an integrating sphere, the DA solutions systematically overshoot numerically simulated DRS (using Monte Carlo approach) by 1–2 percentage points. However, using the former in inverse analysis of the latter can result in much larger artifacts, most notably overestimations of the melanin and blood contents by up to 15%, which must be considered when analyzing experimental DRS. Despite such systematic errors, the described approach allows simple and robust monitoring of physiological changes in human skin, as demonstrated in tests involving temporary obstruction of blood circulation and seasonal variations due to extensive sun exposure.

Reducing Brain Injury of Preterm Infants in the Delivery Room.

Cerebrovascular injury is one of the major detrimental consequences of preterm birth. Recent studies have focused their attention on factors that contribute to the development of brain lesions immediately after birth. Among those factors, hypothermia and lower cerebral oxygen saturation during delivery room resuscitation and high tidal volumes delivered during respiratory support are associated with increased risk of severe neurologic injury. In preterm infants, knowledge about causes and prevention of brain injury must be applied before and at birth. Preventive and therapeutic approaches, including correct timing of cord clamping, monitoring of physiological changes during delivery room resuscitation using pulse oximetry, respiratory function monitoring, near infrared spectroscopy, and alpha EEG, may minimize brain injury, Furthermore, postnatal administration of caffeine or other potential novel treatments (e.g., proangiogenic therapies, antioxidants, hormones, or stem cells) might improve long-term neurodevelopmental outcomes in preterm infants.

Monitoring of Physiological Changes of Uric Acid Concentration in the Blood of Snakes

Abstract The evaluation of uric acid concentrations in the blood of snakes is a crucial tool in the diagnosis of gout and renal disease; both prevalent diseases in captive reptiles. However, without an understanding of the physiological fluctuations in uric acid levels and the absence of distinction that makes pathological changes, biochemical parameters are devalued. This study focuses on investigating the relationship between feeding rate and plasma-uric acid concentrations of snakes. The aim of this investigation is to facilitate a better understanding of the feed-induced changes that occur, and to render the analysis of this biochemical parameter as a more potent diagnostic tool. A total of 10 snakes were used in the study and the basal concentration of uric acid was established prior to feeding via blood biochemical analysis. The snakes were then fed rats and successive postprandial blood samples were taken for the monitoring of uric acid levels. The results demonstrated that feeding led to substantial elevations in the uric acid values, whereby postprandial concentrations were significantly elevated for up to 5 days after feeding. The postprandial elevations in uric acid documented in these snakes were of similar levels reported in snakes afflicted with gout or renal disease. The results demonstrated the significant changes that occur to uric acid levels after feeding, and highlights the resemblance between postprandial increases in uric acid and concentrations reported in snakes suffering from renal disease or gout. To avoid a misdiagnosis and to distinguish transient postprandial hyperuricemia from pathological elevations, collecting sufficient anamnestic data on time since last feeding in performing repeated sampling after one week period of fasting is suggested.

On the emerging role of rabbit as human disease model and the instrumental role of novel transgenic tools

The laboratory rabbit (Oryctolagus cuniculus) is widely used as a model for human diseases, because of its size, which permits non-lethal monitoring of physiological changes and similar disease characteristics. Novel transgenic tools such as, the zinc finger nuclease method and the sleeping beauty transposon mediated or BAC transgenesis were recently adapted to the laboratory rabbit and opened new opportunities in precise tissue and developmental stage specific gene expression/silencing, coupled with increased transgenic efficiencies. Many facets of human development and diseases cannot be investigated in rodents. This is especially true for early prenatal development, its long-lasting effects on health and complex disorders, and some economically important diseases such as atherosclerosis or cardiovascular diseases. The first transgenic rabbits models of arrhythmogenesis mimic human cardiac diseases much better than transgenic mice and hereby underline the importance of non-mouse models. Another emerging field is epigenetic reprogramming and pathogenic mechanisms in diabetic pregnancy, where rabbit models are indispensable. Beyond that rabbit is used for decades as major source of polyclonal antibodies and recently in monoclonal antibody production. Alteration of its genome to increase the efficiency and value of the antibodies by humanization of the immunoglobulin genes, or by increasing the expression of a special receptor (Fc receptor) that augments humoral immune response is a current demand.

Early chloroplastic alterations analysed by optical coherence tomography during a harpin‐induced hypersensitive response

The hypersensitive response has been mostly studied by molecular and biochemical methods after sample destruction. The development of imaging techniques allows the monitoring of physiological changes before any signs of cell death. Here, we follow the early steps of a hypersensitive-like response induced by the bacterial elicitor harpin in Nicotiana sp. We describe cytological modifications after inoculation of the harpin protein, using confocal fluorescence microscopy (CFM) and optical coherence tomography (OCT), an interferometric-based microscopy. The changes detected by CFM occurred 5 h after harpin infiltration and corresponded to a redistribution of the chloroplasts from the upper to the inner regions of the palisade mesophyll cells which could be related to a perturbation in the microtubule network. Using OCT, we were able to detect a decrease in chloroplast backscattered signal as early as 30 min after harpin infiltration. A simple physical model, which accounted for the structure and distribution of thylakoid membranes, suggested that this loss of scattering could be associated with a modification in the refractive index of the thylakoid membranes. Our OCT observations were correlated with a decrease in photosynthesis, emphasizing changes in chloroplast structure as one of the earliest hallmarks of plant hypersensitive cell death.

Frequency and reliability of alarms in the monitoring of cardiac postoperative patients

Postoperative monitoring of cardiac operated patients requires appropriately functioning monitor alarms as well as intensive nursing activity. The limit alarms can be used for detection of life-threatening situations and monitoring of physiological changes in the patient's state. We studied the significance and the frequency of audible alarms during the postoperative intensive care of ten cardiac patients. Of 1307 occasions when such an alarm was activated during the study period of approximately 26 hours per patient, only 139 (10.6%) were significant. The highest proportion of significant audible limit alarms was found during the immediate postoperative period. Heart rate alarms were more reliable than alarms of the other parameters monitored in the study. Possibilities for improving the physiological monitoring and alarm system are discussed.