BioMedical Engineering OnLine最新文献

The aim of this study was to evaluate the feasibility of using a biofeedback-enhanced robotics-assisted tilt table (RATT) to investigate time- and intensity-dependent changes in heart rate variability (HRV) at rest and during heart rate-controlled exercise in patients recovering from a stroke. Twelve patients (age 55.3 years ± 15.6 years, 7 women) completed two separate measurement sessions. The first involved familiarization and system identification to determine parameters of a feedback system for automatic control of heart rate (HR). The second comprised 14 min of rest and 21 min of active exercise during which HR was held constant using feedback control to eliminate cardiovascular drift. HR data were collected using a chest-belt HR sensor, and raw RR intervals were employed for HRV analysis during periods of rest (0-7 min and 7-14 min) and exercise (5-13 min and 13-21 min). A biofeedback-enhanced, robotics-assisted tilt table can be successfully employed to perform heart rate-controlled exercises in patients after a stroke. All HRV metrics were substantially lower during exercise compared to rest. In the rest period, HRV values during 0-7 min were lower than during 7-14 min, in line with a slight HR decrease over the entire rest period. During exercise, HRV values during 5-13 min were higher than during 13-21 min, suggesting a time-dependent HRV decrease. All HRV metrics exhibited intensity- and time-dependent changes: higher HRV at rest and decreasing HRV over time. Understanding these HRV characteristics will support the development of heart rate-controlled exercise regimens and protocols for examining HRV changes during exercise in patients.

Purpose: This study aims to accurately predict the effects of hormonal therapy on prostate cancer (PC) lesions by integrating multi-modality magnetic resonance imaging (MRI) and the clinical marker prostate-specific antigen (PSA). It addresses the limitations of Convolutional Neural Networks (CNNs) in capturing long-range spatial relations and the Vision Transformer (ViT)'s deficiency in localization information due to consecutive downsampling. The research question focuses on improving PC response prediction accuracy by combining both approaches.

Methods: We propose a 3D multi-branch CNN Transformer (CNNFormer) model, integrating 3D CNN and 3D ViT. Each branch of the model utilizes a 3D CNN to encode volumetric images into high-level feature representations, preserving detailed localization, while the 3D ViT extracts global salient features. The framework was evaluated on a 39-individual patient cohort, stratified by PSA biomarker status.

Results: Our framework achieved remarkable performance in differentiating responders and non-responders to hormonal therapy, with an accuracy of 97.50%, sensitivity of 100%, and specificity of 95.83%. These results demonstrate the effectiveness of the CNNFormer model, despite the cohort's small size.

Conclusion: The findings emphasize the framework's potential in enhancing personalized PC treatment planning and monitoring. By combining the strengths of CNN and ViT, the proposed approach offers robust, accurate prediction of PC response to hormonal therapy, with implications for improving clinical decision-making.

Background: Experimental knee implant wear testing according to ISO 14243 is a standard procedure, but it inherently possesses limitations for preclinical evaluations due to extended testing periods and costly infrastructure. In an effort to overcome these limitations, we hereby develop and experimentally validate a finite-element (FE)-based algorithm, including a novel cross-shear and contact pressure dependent wear and creep model, and apply it towards understanding the sensitivity of wear outcomes to the applied boundary conditions.

Methods: Specifically, we investigated the application of in vivo data for level walking from the publicly available "Stan" data set, which contains single representative tibiofemoral loads and kinematics derived from in vivo measurements of six subjects, and compared wear outcomes against those obtained using the ISO standard boundary conditions. To provide validation of the numerical models, this comparison was reproduced experimentally on a six-station knee wear simulator over 5 million cycles, testing the same implant Stan's data was obtained from.

Results: Experimental implementation of Stan's boundary conditions in displacement control resulted in approximately three times higher wear rates (4.4 vs. 1.6 mm³ per million cycles) and a more anterior wear pattern compared to the ISO standard in force control. While a force-controlled ISO FE model was unable to reproduce the bench test kinematics, and thus wear rate, due to a necessarily simplified representation of the simulator machine, similar but displacement-controlled FE models accurately predicted the laboratory wear tests for both ISO and Stan boundary conditions. The credibility of the in silico wear and creep model was further established per the ASME V&V-40 standard.

Conclusions: The FE wear model is suitable for supporting future patient-specific models and development of novel implant designs. Incorporating the Stan data set alongside ISO boundary conditions emphasized the value of using measured kinematics in displacement control for reliably replicating in vivo joint mechanics in wear simulation. Future work should focus on expanding the range of daily activities simulated and addressing model sensitivity to contact mechanics to further enhance predictive accuracy.

Background: Despite the development of various therapeutic approaches over the past decades, the treatment of glioblastoma multiforme (GBM) remains a major challenge. The extracellular adenosine-generating enzyme, CD73, is involved in the pathogenesis and progression of GBM, and targeting CD73 may represent a novel approach to treat this cancer. In this study, three-dimensional culture systems based on three hydrogel compositions were characterized and an optimal type was selected to simulate the GBM microenvironment. In addition, the effect of a CD73 inhibitor on GBM cell aggregates and spheroids was investigated as a potential therapeutic approach for this disease.

Methods: Rheology measurements, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and cell proliferation assays were performed to analyze the synthesized hydrogel and select an optimal formulation. The viability of tumor cells in the optimal hydrogel was examined histologically and by confocal microscopy. In addition, the sensitivity of the tumor cells to the CD73 inhibitor was investigated using a cell proliferation assay and real-time PCR.

Results: The data showed that the hydrogel containing 5 wt% gelatin and 5 wt% sodium alginate had better rheological properties and higher cell viability. Therefore, it could provide a more suitable environment for GBM cells and better mimic the natural microenvironment. GBM cells treated with CD73 inhibitors significantly decreased the proliferation rate and expression of VEGF and HIF1-α in the optimal hydrogel.

Conclusion: Our current research demonstrates the great potential of CD73 inhibitor for clinical translation of cancer studies by analyzing the behavior and function of 3D tumor cells, and thus for more effective treatment protocols for GBM.

Chemotherapy-induced cardiotoxicity is a significant concern in cancer treatment, as certain chemotherapeutic agents can have adverse effects on the cardiovascular system. This can lead to a range of cardiac complications, including heart failure, arrhythmias, myocardial dysfunction, pericardial complications, and vascular toxicity. Strategies to mitigate chemotherapy-induced cardiotoxicity may include the use of cardioprotective agents (e.g., dexrazoxane), dose adjustments, alternative treatment regimens, and the implementation of preventive measures, such as lifestyle modifications and the management of cardiovascular risk factors. Ginsenosides, the active compounds found in ginseng (Panax ginseng), have been studied for their potential cardioprotective effects in the context of chemotherapy-induced cardiotoxicity. In this review, we investigate the cardioprotective effect of ginsenosides in chemotherapy-induced cardiotoxicity. Ginsenosides have been shown to possess potent antioxidant properties, which can help mitigate the oxidative stress and inflammation associated with chemotherapy-induced cardiac injury. They can modulate the expression of antioxidant enzymes and reduce the production of reactive oxygen species, thereby protecting cardiomyocytes from damage. Ginsenosides can also inhibit apoptosis (programmed cell death) of cardiomyocytes, which is a key mechanism underlying chemotherapy-induced cardiotoxicity. Modulation of ion channels, improvement of lipid profiles, anti-platelet and anti-thrombotic effects, and promotion of angiogenesis and neovascularization are another important mechanisms behind potential effects of ginsenosides on cardiovascular health. Ginsenosides can improve various parameters of cardiac function, such as ejection fraction, fractional shortening, and cardiac output, in animal models of chemotherapy-induced cardiotoxicity. The cardioprotective effects of ginsenosides have been observed in preclinical studies using various chemotherapeutic agents, including doxorubicin, cisplatin, and 5-fluorouracil. However, more clinical studies are needed to fully elucidate the therapeutic potential of ginsenosides in preventing and managing chemotherapy-induced cardiotoxicity in cancer patients.

Background: Stroke is the leading cause of acquired motor deficiencies in adults. Restoring prehension abilities is challenging for individuals who have not recovered active hand opening capacities after their rehabilitation. Self-triggered functional electrical stimulation applied to finger extensor muscles to restore grasping abilities in daily life is called grasp neuroprosthesis (GNP) and remains poorly accessible to the post-stroke population. Thus, we developed a GNP prototype with self-triggering control modalities adapted to the characteristics of the post-stroke population and assessed its impact on abilities.

Methods: Through two clinical research protocols, 22 stroke participants used the GNP and its control modalities (EMG activity of a pre-defined muscle, IMU motion detection, foot switches and voice commands) for 3 to 5 sessions over a week. The NeuroPrehens software interpreted user commands through input signals from electromyographic, inertial, foot switches or microphone sensors to trigger an external electrical stimulator using two bipolar channels with surface electrodes. Users tested a panel of 9 control modalities, subjectively evaluated in ease-of-use and reliability with scores out of 10 and selected a preferred one before training with the GNP to perform functional unimanual standardized prehension tasks in a seated position. The responsiveness and functional impact of the GNP were assessed through a posteriori analysis of video recordings of these tasks across the two blinded evaluation multi-crossover N-of-1 randomized controlled trials.

Results: Non-paretic foot triggering, whether from EMG or IMU, received the highest scores in both ease-of-use (median scores out of 10: EMG 10, IMU 9) and reliability (EMG 9, IMU 9) and were found viable and appreciated by users, like voice control and head lateral inclination modalities. The assessment of the system's general responsiveness combined with the control modalities latencies revealed median (95% confidence interval) durations between user intent and FES triggering of 333 ms (211 to 561), 217 ms (167 to 355) and 467 ms (147 to 728) for the IMU, EMG and voice control types of modalities, respectively. The functional improvement with the use of the GNP was significant in the two prehension tasks evaluated, with a median (95% confidence interval) improvement of 3 (- 1 to 5) points out of 5.

Conclusions: The GNP prototype and its control modalities were well suited to the post-stroke population in terms of self-triggering, responsiveness and restoration of functional grasping abilities. A wearable version of this device is being developed to improve prehension abilities at home.

Trial registration: Both studies are registered on clinicaltrials.gov: NCT03946488, registered May 10, 2019 and NCT04804384, registered March 18, 2021.

Background: Spinal cord injury (SCI) often leads to the loss of urinary sensation, making urination difficult. In a previous experiment involving six healthy participants, we measured heartbeat-induced acoustic pulse waves (HAPWs) at the mid-back, calculated time-series power spectra of heart rate gradients at three ultralow/very low frequencies, distinguished and formulated waveform characteristics (one characteristic for each power spectrum, nearly uniform across participants) at times of increased urine in the bladder and heightened urges to urinate, and developed an algorithm with five of these power spectra to identify when urination is needed by extracting the waveform portion (continuous timepoints) where all of the characteristics were consistent with the formulated characteristics. The objective of this study was to verify the validity of the algorithm fed with data from measured HAPW of participants with SCI and to adapt the algorithm for these individuals.

Methods: In ten participants with SCI, we measured HAPWs continuously and urine volume intermittently, and obtained scores related to urinary sensation. A Boolean output at each data point was obtained by the algorithm fed with the calculated power spectra from each participant's HAPW. Notable times included when the output was positive or when the need to urinate (= ( +)) was judged from the urine volume and urinary sensation scores. The outputs at these notable times were examined with the need to urinate and determined to be true/false. The accuracy of the algorithm was evaluated by the number of true/false-positive/negative points via the F-score with a binary classification model. We attempted to adapt the algorithm for participants with SCI.

Results: The outputs at 13 notable times were examined, yielding seven true-positive, one false-positive, and five false-negative times, with an F-score of 0.70. The algorithm was modified by replacing three thresholds that determine the extraction condition for the slope in the power spectral waveform with new values that included all 12 true-positive points.

Conclusions: Without changing the use of ultralow/very low frequencies or significantly modifying the extraction conditions, the modified algorithm did not miss any true urination times or identify false urination times in ten participants with SCI.

Objectives: To explore the expression of periostin in the epithelium of cholesteatoma with different destruction degrees of the ossicular chain and its clinical value in predicting postoperative hearing recovery.

Methods: Retrospective analysis was conducted on the clinical data of 100 patients with middle ear cholesteatoma (the cholesteatoma group) admitted to our hospital. Another 100 patients without middle ear cholesteatoma treated in our hospital during the same period were included in the non-cholesteatoma group. Middle ear cholesteatoma patients were further divided into a normal group, a partial destruction group, and a complete destruction group based on the destruction degree of the ossicular chain (Maresh grading). After the treatment, 75 cases were considered as the effective group and 25 cases as the ineffective group. The expression of tumor necrosis factor-alpha, Interleukin 6, and periostin in the epithelium of middle ear cholesteatoma patients with different destruction degrees of the ossicular chain and different therapeutic effects were compared. The correlation between periostin and inflammatory factors was analyzed using Pearson analysis. The predictive value of tumor necrosis factor-alpha, Interleukin 6, and periostin on treatment effect was valued using the receiver operating characteristic curve.

Results: Patients in the cholesteatoma group had a much higher content of tumor necrosis factor-alpha, Interleukin 6, and periostin than those in the non-cholesteatoma group (P < 0.001). The expression of tumor necrosis factor-alpha, Interleukin 6, and periostin was also largely increased with the destruction group of the ossicular chain. Patients in the ineffective group had much higher expression of tumor necrosis factor-alpha, Interleukin 6, and periostin than those in the effective group (P < 0.001). The Pearson correlation analysis results showed that periostin was positively correlated with the content of tumor necrosis factor-alpha and interleukin 6 (P = 0.868, 0.880, P < 0.001). The areas under the curve of individual or joint tumor necrosis factor-alpha, Interleukin 6, and periostin were 0.627, 0.793, 0.822, and 0.892, respectively.

Conclusions: The expressions of periostin, Interleukin 6, and tumor necrosis factor-alpha were markedly increased in the epithelium of middle ear cholesteatoma patients, which were gradually increased with the aggravation of the ossicular chain destruction. Periostin, Interleukin 6, and tumor necrosis factor-alpha could be used as important indicators to predict postoperative hearing recovery.

Background: Chronic venous insufficiency (CVI) is a common disease with a high prevalence. Incompetent venous valves are considered as one of the main causes. Besides compression therapy, various surgical therapies are practiced, whereby the reconstruction of valves is of central importance. There is an unmet clinical need, no valve prosthesis is commercially available to date. This work introduces two versions of a patented prosthetic bicuspid valve design made of electrospun thermoplastic silicone polycarbonate polyurethane (TSPCU) nanofiber leaflets attached in a nitinol stent, and their performance in static and pulsatile operation.

Results: The valves mainly fulfill the requirements widely accepted in literature. Valves of both versions were functional in the physiological pressure range up to 50 mmHg with design specific differences.

Conclusions: The here introduced design versions act as a platform technology and can be tailored for an intended implantation site. Evaluation of the original and modified valve concept demonstrated efficacy, with limitations at higher loads for original design. At the current state, the modification is preferable for fabrication, as one processing step is eliminated. Moreover, specific design recommendations could be drawn for valves of similar basic structure. Future work will focus on long-term performance and biocompatibility prior to the initiation of preclinical in vivo studies.

Objective: To explore the application effect of enhanced recovery after surgery (ERAS) for patients with hepatolithiasis undergoing hepatectomy.

Methods: A retrospective comparative analysis was performed on the clinical data of 120 patients with hepatolithiasis who were admitted to the Department of Hepatobiliary Surgery in our hospital between December 2017 and May 2022 using convenience sampling.

Results: There were differences in the impact of different management modes on blood glucose and visual analogue scale (VAS) scores between the two groups of patients (F_{blood glucose} = 32.581, F_VAS = 41.472, all P < 0.001). The average blood glucose levels in the traditional group were higher than those in the ERAS group at two time points, and the VAS scores in the former group were higher than those in the latter at 6, 12 and 24 h after surgery. The remifentanil dosage (49.89 ± 12.12 vs 57.84 ± 11.43 mL, t = - 2.475, P = 0.016), patient-controlled analgesia frequency (3.83 ± 2.23 vs 5.57 ± 3.52 times, t = - 2.481, P = 0.015) and analgesic supplementation frequency (0.57 ± 0.73 vs 1.07 ± 1.02 times, t = - 2.653, P = 0.010) in the ERAS group were all lower than those in the traditional group. Different management modes had different effects on the levels of procalcitonin (PCT), interleukin-6 (IL-6), C-reactive protein (CRP) and white blood cell count (WBC) in the two groups of patients (F_PCT = 45.371, F_IL-6 = 43.466, F_CRP = 51.364, F_WBC = 65.674, all P < 0.001). The levels of PCT, IL-6, CRP and WBC in the ERAS group were lower than those in the traditional group at three time points: postoperative day 1, 7 and 14. The postoperative hospital stay (8.41 ± 2.55 vs 11.61 ± 3.34 d, t = - 7.812, P < 0.001) and proportion of postoperative complications (9.61% vs 26.47%, χ² = 5.403, P = 0.020) in the ERAS group were lower than those in the traditional group.

Conclusion: The application of ERAS effectively reduces the perioperative stress response, shortens the postoperative length of hospital stay and lowers the overall incidence of postoperative complications in patients with hepatolithiasis.