Search Results (240)

A 7224C high-speed angular contact ball bearing used in a multi-wire sawing machine is selected as the research object to investigate the cage dynamic characteristics under oil-lubricated operating conditions. First, in order to determine the oil-phase volume fraction on the cage surface, a fluid-domain model of the bearing cavity is established, and numerical simulations are performed using the VOF multiphase-flow method coupled with the RNG k-ε turbulence model. The effects of the guiding clearance, pocket clearance, and rotational speed are analyzed, and a regression equation for the cage-surface oil-phase volume fraction is developed based on a uniform test design. Subsequently, a bearing dynamic model is constructed, in which lubrication-related parameters are determined based on the regression equation, and the force balance and equations of motion for each component are derived. Finally, using the slip ratio and the deviation ratio of the cage-centroid whirl velocity as evaluation indices, the influences of multiple parameters on cage stability are examined. The results indicate that increasing the clearances and rotational speed leads to a higher slip ratio, whereas increasing the axial and radial loads reduces the slip ratio. Moreover, enlarging the guiding clearance and increasing the axial load improve cage stability, while a larger pocket clearance and an excessively high radial load deteriorate cage stability. Full article

Background: Cage subsidence (CS) is among the main complications after oblique lumbar interbody fusion (OLIF) and may lead to the failure of indirect decompression. Accurate preoperative bone quality assessment is critical for risk stratification, yet the optimal imaging modality and diagnostic threshold remain unclear. Objectives: This study aimed to determine a quantitative computed tomography (QCT)-derived volumetric bone mineral density (vBMD) threshold for predicting CS after OLIF with posterior fixation. Methods: Patients undergoing OLIF with posterior fixation between July 2017 and March 2020 were retrospectively enrolled. Preoperative vBMD was measured using QCT as the average L2–L4 trabecular volumetric BMD. CS was defined as a loss of more than 2 mm of disk height on sagittal midline CT views between 3 days postoperatively and the last follow-up. Clinical and radiographic parameters including gender, age, body mass index, vBMD, number of operative levels, cage dimensions, disk height, segmental lordosis, intraoperative endplate injury, and fusion status were analyzed. Results: 86 patients (107 operative levels) with a mean follow-up of 20.6 months were included; 25 levels (23.4%) developed CS. Multivariate logistic regression identified vBMD (p < 0.001; OR 0.947; 95% CI 0.923–0.972) and intraoperative endplate injury (p = 0.031; OR 3.640; 95% CI 1.125–11.776) as independent risk factors. The area under the receiver operating characteristic curve (AUC) for vBMD was 0.847 (95% CI, 0.762–0.932), with an optimal threshold of 83.0 mg/cm³ (sensitivity 84.0%, specificity 76.8%). This threshold closely aligns with the American College of Radiology QCT criterion for osteoporosis (80 mg/cm³); however, given that it was derived from a single-center retrospective cohort, external validation in multi-center studies is warranted before broad clinical adoption. Fusion rates differed significantly between CS and non-CS groups (84.0% vs. 96.3%, p = 0.029). Conclusions: QCT-derived vBMD provides a phantom-calibrated, protocol-standardized metric for preoperative risk stratification of cage subsidence after OLIF. Full article

Background/Objectives: To identify predictors of successful fusion and adjacent segment disease (ASD) following ALIF. Methods: Records of patients undergoing one- or two-level ALIF were queried for baseline and postoperative radiographic data, demographics, operative notes, and implant characteristics. All had ≥1 year of follow-up with CT, and multivariable Cox regression was used to identify predictors of radiographic fusion through the interbody, ASD, and ASD requiring reoperation. Results: In total, 177 patients (median 59 yr; 52.5% male) were treated at 245 unique levels, of which 193 fused (81.3% with posterior fixation and 59.6% with standalone), 43 had ASD (17.6%), and 14 had ASD requiring reoperation (5.7%). Fusion was predicted by anterior cage placement (HR 0.94/mm; 95% CI [0.90, 0.98]; p = 0.003) and BMP use (HR 1.92; [1.15, 3.18]; p = 0.012). Radiographic ASD was predicted by older age (HR 1.08 per year; [1.03, 1.14]; p < 0.001), undergoing a revision [vs. index] fusion operation (HR 3.51; [1.44; 8.59]; p = 0.006), lower preoperative disc height (HR 0.83/mm; [0.74, 0.94]; p = 0.003), and preoperative facet vacuum phenomenon (HR 2.46; [1.18, 5.15]; p = 0.017). None of the extracted variables predicted reoperation for ASD. Conclusions: BMP use along with anterior cage placement and posterior fixation may improve the odds of fusion through the interbody following one- or two-level ALIF. Adjacent segment pathology is more common in patients with greater preoperative degenerative pathology (vacuum sign; more collapsed disc) and advanced age. Pelvic fixation did not improve fusion odds, but the data highlight the benefits of supplementary posterior fixation vs. standalone ALIF. Full article

This paper presents a novel distributed coordination framework for multi-agent robotic swarms tailored for smart transportation applications. The proposed approach addresses the critical pre-transportation phase where a fleet of mobile robots, eventually with different sizes, must converge to fixed positions around an object to ensure effective caging within a user-defined prescribed time. By leveraging a time-varying diffeomorphic mapping based on an affine transformation, the strategy embeds prescribed-time guarantees within a swarm-inspired framework that maps agents between virtual and real reference frames. This methodology ensures the simultaneous achievement of precise target convergence, finite-time stability regardless of initial conditions, and inherent collision avoidance by explicitly considering the physical footprint of each robotic unit. The control protocol is first derived for scalar systems and subsequently extended to multidimensional robotic fleets using additional diffeomorphism-based techniques, which allow for the management of multiple non-interacting swarms to reduce network communication overhead. Full article

Background/Objectives: Ureteral complications following oblique lumbar interbody fusion (OLIF) are uncommon and are typically attributed to direct mechanical injury. Functional ureteral obstruction without overt ureteral damage remains poorly characterized. We report two cases that provide clinical and intraoperative evidence of a previously underrecognized mechanism of ureteral obstruction associated with anterior cage positioning during OLIF. Case Presentation: Among 180 OLIF procedures performed by a single surgeon, two cases (1.1%) of postoperative or intraoperative ureteral compromise without direct structural injury were identified. In the first case, postoperative imaging revealed hydronephrosis and focal angulation of the left proximal ureter at the level of the interbody cage, without contrast extravasation. The obstruction was managed with double-J ureteral stenting, and serial renal function monitoring confirmed preserved renal function throughout the clinical course. In the second case, retroperitoneal tissue including the ureter was directly observed intraoperatively to be interposed between the anterior longitudinal ligament and the interbody cage during anterior cage placement. Release of the interposed tissue resulted in immediate ureteral decompression without structural damage. Correlation of the postoperative findings in the first case with the intraoperative observations of the second case supports a unified mechanistic explanation: anterior cage advancement may draw retroperitoneal tissue into the cage–anterior longitudinal ligament interface, subjecting the ureter to focal compression or angulation. Conclusions: Functional ureteral obstruction during OLIF may occur secondary to retroperitoneal tissue interposition rather than direct ureteral trauma. Awareness of this mechanism and meticulous protection of the anterior retroperitoneal layer during cage advancement may help prevent avoidable ureteral complications. Full article

This study presents a systematic topological progression and multi-objective optimization of a Permanent Magnet-assisted Non-overlapping Winding Line-Start Synchronous Reluctance Motor (PMaNWLS-SynRM) for industrial applications. To explicitly highlight the core contribution, the research establishes a rigorous comparative framework evaluating the transition from a conventional 4-pole/36-slot distributed winding (DW) to a 2 × 12-slot non-overlapping winding (NW) architecture. Baseline results demonstrate that the NW configuration shortens end-turns, successfully reducing total electromagnetic losses from 417 W to 349 W and improving steady-state efficiency from 93.7% to 95.1%. To overcome the inherent starting limitations of pure synchronous reluctance machines, an aluminum squirrel-cage is integrated to enable robust direct-on-line (DOL) synchronization, while NdFeB permanent magnets are embedded within the rotor flux barriers to mitigate asynchronous spatial harmonics and elevate torque density. Finite element analysis (FEA) confirms this magnetic assistance raises the average synchronous torque to 65.8 Nm while suppressing absolute torque ripple to 1.37 Nm. Finally, an evolutionary genetic algorithm is deployed across 440 iterative configurations to resolve geometric multi-physics conflicts. The finalized optimized design achieves a 13.2 kW output power at 1800 rpm, maximizing average torque to 70.12 Nm and strictly dampening absolute torque ripple to an industry-acceptable 1.04 Nm. Operating with an aggregated total loss of 1382 W, the optimized PMaNWLS-SynRM yields a 90.5% operational efficiency, definitively validating its suitability as an ultra-premium IE4/IE5 alternative to conventional induction motors. Full article

Background and Objectives: Ventral stabilization of thoracolumbar spine fractures can be achieved using different interbody reconstruction techniques, including titanium cages, vertebral body replacements (VBR), and autologous pelvic bone grafts (APBG). Although all approaches aim to restore anterior column stability and alignment, comparative data on long-term patient-reported outcomes remain limited. The objective of this study was to compare long-term patient-reported wellbeing following ventral stabilization using these three techniques. Materials and Methods: A retrospective, non-randomized single-center cohort study with prospective follow-up was analyzed. Treatment allocation was indication-based. Ninety-one patients treated between 2008 and 2018 underwent ventral stabilization using cage implantation (n = 12), vertebral body replacement (n = 45), or autologous pelvic bone grafting (n = 34). Clinical outcome was assessed at least 12 months postoperatively using a modified Visual Analog Scale Spine Score (VAS-Spine). Statistical analysis included linear and ordinal regression adjusted for age and sex. Potential baseline differences between groups were considered in the interpretation of the results. Results: Sixty-three patients (mean age 52 ± 15 years; 41% female) completed follow-up. The mean VAS-Spine score was lowest after cage implantation (2.7 ± 3.6), followed by VBR (3.9 ± 2.8) and APBG (4.9 ± 1.8; p* = 0.021). The observed difference between cage and APBG approached the minimal clinically important difference reported for VAS-based measures. Patients treated with cage implantation reported less pain during rest and activity and fewer limitations in daily life. No significant differences were observed regarding age or sex. Conclusions: In this observational cohort, cage implantation was associated with more favorable patient-reported outcomes compared with VBR and APBG. Autologous pelvic bone grafting was associated with worse patient-reported outcomes, potentially related to donor-site morbidity. Given the non-randomized design and potential confounding, these findings should be interpreted as associative and hypothesis-generating. Full article

Background/Objectives: Improving rabbit welfare through alternative housing systems requires a better understanding of how environmental conditions modulate physiological and immune responses at the molecular level. This study aimed to evaluate the influence of different rearing systems on the expression of genes associated with inflammation, immune regulation, and stress response in Termond White rabbits. Methods: After weaning (35 days of age), Termond White females (n = 16 per group) were allocated to five housing systems differing in space allowance and activity opportunities: hutches with outdoor runs, rabbit tractor cages with outdoor runs, single-floor indoor cages without bedding, indoor pens on deep litter, and modified indoor cages (two cages connected with a plastic pipe). At slaughter weight (2600–2900 g; 90–120 days), blood and spleen samples were collected. The relative expression of IL6, CXCR1, IL10, TGFB1, IL8, PTGS2, IL1B, and TNF was quantified by RT-qPCR using the 2^−ΔΔCt method, with ACTB and B2M as reference genes. Results: The housing system significantly affected the expression of most analysed genes in peripheral blood (IL6, CXCR1, IL1B, PTGS2, IL8, TNF, and IL10; p ≤ 0.05), whereas in the spleen significant differences were observed only for selected genes (IL1B, TNF, CXCR1, IL10, and TGFB1), with no effect detected for IL6, IL8, and PTGS2 (p > 0.05). In blood, system-dependent differences were observed for both pro-inflammatory and regulatory genes, with some housing conditions associated with higher expression of inflammatory markers. In the spleen, the response was more selective and gene-specific, suggesting tissue-dependent modulation of immune-related pathways. Conclusions: Rearing environment influences the expression of immune-related genes in Termond White rabbits; however, these effects appear to be tissue-dependent and vary among specific genes. The observed transcriptional changes suggest potential associations between housing conditions and immune responses, but further studies integrating behavioural, physiological, and protein-level data are required to confirm their relevance for animal welfare assessment. Full article

Background/Objectives: Poor bone quality is strongly associated with adverse surgical events. Although dual-energy X-ray absorptiometry (DXA) remains the gold standard for bone mineral density (BMD) assessment, logistical barriers may limit its preoperative application. The Endplate Bone Quality (EBQ) score is an MRI-derived metric quantifying subchondral bone quality at the vertebral endplate with demonstrated predictive value for cage subsidence following lumbar interbody fusion. However, EBQ has been measured exclusively at the operative level in surgical cohorts. This study aimed to assess level-specific EBQ scores across the entire lumbar spine and compare distributions across age, sex and osteoporosis subgroups. Methods: A single-institution retrospective review of T1-weighted lumbar MRI studies from patients evaluated for lower back pain from 2020 to 2025 was performed. EBQ was independently scored by two blinded raters at each disc space from L1–L2 to L5–S1 using 3 mm endplate ROIs normalized to a CSF ROI at L3. Interrater reliability was assessed via ICC, Pearson correlation, and RMSE. Patients were stratified by age (≤60 vs. >60 years), sex, and osteoporosis status, and subgroup comparisons were performed for overall and level-specific EBQ score. Results: A total of 96 patients with an average age of 61.0 ± 9.42 years were included in this study. The majority of patients included were female (87.5%), and 18.8% had been diagnosed with osteoporosis. EBQ scores demonstrated a progressive caudal increase across all subgroups from L2–L3 to L5–S1. Overall interrater reliability was acceptable (ICC = 0.76), with level-specific ICCs ranging from 0.70 to 0.83. No significant differences were observed between age or sex subgroups. Osteoporotic patients demonstrated significantly higher EBQ at L1–L2, L2–L3, and overall (all p < 0.05), with no significant differences at L3–L4 through L5–S1. Conclusions: This study provides normative, level-specific EBQ reference data throughout all levels of the lumbar spine. The increase in EBQ scores seen among caudal levels and reduced osteoporotic discriminatory power support the importance of level-specific context when interpreting EBQ thresholds. These findings may support future studies evaluating threshold development for EBQ. Full article

In large-scale caged broiler farms, daily inspection of dead broilers is essential for flock health management and disease prevention. To address the significant performance degradation of existing methods under challenging conditions such as poor lighting, severe occlusion, and complex backgrounds, this paper proposes a dual-modal dynamic hybrid convolutional feature fusion method for dead bird detection based on an improved YOLO11 framework, termed YOLO11-DualDynConv-FF. First, a dual-modal fusion network architecture was developed to combine RGB and infrared (IR) images, enabling the model to simultaneously process both modalities. By integrating complementary information from RGB and IR data, the proposed method significantly improved detection accuracy and efficiency under low-light conditions. Second, a dynamic hybrid convolution feature fusion module was designed to merge multi-scale feature maps with contextual information, allowing the network to capture fine-grained details and adapt better to complex farming environments. In addition, an occlusion-aware module was introduced to specifically address the physical occlusion challenges prevalent in crowded cage settings. Comparative experiments and ablation studies involving multiple object detection networks were conducted to evaluate the proposed method. The results show that the improved YOLO11 model achieves superior performance, with precision, recall, F1-score, and mAP@0.5 reaching 92.6%, 79.0%, 0.85, and 80.1%, respectively. These results represent improvements of 2.0%, 5.0%, 0.17, and 12.1%, respectively, over the original YOLO11 model. Compared with existing approaches, the proposed model is better suited to complex real-world poultry farming environments and achieves higher detection accuracy, providing a valuable reference for intelligent monitoring in caged poultry farming. Full article

Background/Objectives: Spotty liver disease (SLD), caused by Campylobacter hepaticus, is an emerging disease that leads to substantial production losses in the egg industry. The shift toward antibiotic-free and cage-free production systems has further intensified the impact of SLD. The current control measures largely rely on autogenous killed vaccines; however, their use is constrained by the slow and fastidious growth of C. hepaticus and inconsistent efficacy. To overcome these limitations, this study aimed to identify immunogenic mimotopes as vaccine candidates and express them on the surface of an avian pathogenic Escherichia coli (APEC) vector. Methods: To identify immunogenic mimotopes, Ph.D.-12 phage display peptide library was screened using the hyperimmune serum raised against killed whole-cell C. hepaticus in specific pathogen-free chickens. Subsequently, the outer membrane protein C (OmpC) of E. coli was used as a scaffold for constructing a surface display library. A single restriction site, PstI, located in the seventh external loop of OmpC, was strategically utilized to insert each 12-amino-acid mimotope with a six-histidine (6xHis) tag sequence at its N-terminus, generating ompC + mimotope fusion constructs. These constructs were cloned into the inducible expression vector pTrc and electroporated into an E. coli DH5α ∆ompC strain, which lacked ompC. The surface expression of the mimotopes was confirmed in vitro. The verified ompC + mimotope constructs were subsequently subcloned into the pYA3422 constitutive expression vector and electroporated into the APEC PSUO78 ∆aroA ∆asd vaccine vector strain. A chicken vaccination–challenge trial was conducted using nine groups of chickens, including an unvaccinated challenged control and an unvaccinated–unchallenged negative control. Each experimental group received a mixture of two recombinant E. coli strains carrying different mimotopes at a dose of 1 × 10⁹ CFU, which were administered orally twice at 16 and 18 weeks of age. Results: Fourteen immunogenic mimotopes corresponding to 13 different C. hepaticus proteins were identified as potential vaccine candidates. The expression of these mimotopes on the surface of the E. coli was successfully demonstrated using the OmpC-mediated surface display system. Of the 14 mimotopes tested, two flagellar-related peptides and one major outer membrane protein (MOMP)-derived peptide elicited significant immune responses and conferred protection against the C. hepaticus challenge. Conclusions: We successfully developed a functional E. coli surface display system that was capable of expressing 12-amino-acid mimotopes of C. hepaticus, providing a robust platform for evaluating vaccine candidates against SLD. Immunogenicity and efficacy studies in chickens demonstrated that three identified mimotopes conferred protection against C. hepaticus colonization of the bile and liver. Future in vivo investigations are necessary to develop and evaluate the immunogenicity and protective efficacy of a multivalent mimotope vaccine consisting of three identified mimotopes against both C. hepaticus and APEC, utilizing the ΔaroA Δasd APEC PSU078 strain as the vaccine vector. Full article

Background/Objectives: Lumbar interbody fusion (LIF) is widely utilized to treat multilevel degenerative lumbar spine pathologies. This systematic review aimed to comprehensively review lateral and posterior multilevel LIF procedures and their clinical and radiographic outcomes. Methods: Following the PRISMA guidelines, a search of PubMed, Embase, Web of Science, and Cochrane identified eligible studies. Patient demographics, as well as clinical and radiographic outcomes were collected. Risk of bias was assessed using the MINORS criteria, while randomized trials were evaluated using the RoB-2 tool. An extensive subgroup analysis was completed when that was possible. Results: A total of 45 studies were included consisting of 5623 patients. The pooled outcomes indicated that TLIF demonstrated the lowest operative duration (198.7 ± 77.83 min) and LOS (5.09 ± 2.5 days), alongside favorable ODI (33.68 ± 6.43), VAS leg pain (5.39 ± 0.66), and VAS back pain (4.67 ± 0.79) score gains. Comparative evidence found that LLIF and OLIF provided advantageous radiographic improvement to the posterior approaches. Comparative evidence on techniques challenged the use of autogenous bone within PLIF, PEEK over HA/PA66 cages, and found no advantages in unilateral decompression within TLIF. There was minimal clinical difference in evidence assessing MIS (minimally invasive) vs. open-TLIF or unilateral vs. bilateral pedicle screw fixation (PSF). Conclusions: This is the first systematic review of the multilevel LIF literature, revealing that while pooled data favored TLIF, a publication bias was detected, and comparative evidence reported advantages for lateral and oblique approaches. Given the lack of conclusive evidence, robust study designs are needed to guide clinical decision-making for multilevel lumbar pathology. Full article

Background/Objectives: Interbody fusion cages provide both structural support and a biologically favorable environment for osseointegration. Through recent decades, cage design and biomaterial selection have evolved to more adapted implants in different concept philosophies. Based on this development, the objective of this work was to develop a systematic review of the state of the art regarding spine interbody cage concepts on the market and anticipate future directions in cage design. Methods: A systematic review following PRISMA 2020 guidelines was conducted in three databases of reference, Scopus, PubMed and Mendeley, in September 2025, considering results from between 2015 and the present using the following keywords: spine, interbody, cage and concept. A revision of the first results was performed, and duplicate entries were excluded, as well as papers without a firm relevance for cage design concepts. Results: This search resulted in 76 selected papers and different design concepts and clinical outputs, and after a duplicate analysis, just 40 papers were selected. The material properties may play an important role in the characteristics of the implant and critically influence load-sharing and bone ingrowth. Surface modifications, including texturing, porosity engineering, and osteoconductive coatings, have been introduced to enhance cellular adhesion and fusion rates. It was observed through the research performed that the main problems are related to micromobility, implant displacement and stress shielding effects in adjacent vertebras. Conclusions: Among the different evolutions observed in cages through the years, design changes played an important role in adapting each case. Knowing that the design could be strongly influenced by the surgical approach used (anterior, posterior, transforaminal or lateral) and bone quality, it is also possible to find, nowadays, different options for different needs that are only accessible due to the technological advances in additive manufacturing, which allowed the development of patient-specific implants. Full article

Background/Objectives: Thoraco-abdominal asynchrony (TAA) is a key mechanical consequence of severe chronic obstructive pulmonary disease (COPD), particularly during acute exacerbations (AECOPD), when dynamic hyperinflation and diaphragmatic dysfunction impair the coordination between rib cage and abdominal motion. Continuous, non-invasive monitoring of respiratory mechanics may provide valuable information on clinical evolution during hospitalization. This study aimed to evaluate Global Phase Delay (GPD) as a longitudinal marker of TAA in hospitalized AECOPD patients and to explore its ability to reflect disease severity and short-term clinical evolution using repeated measurements obtained with thoracic and abdominal respiratory belts using respiratory inductance plethysmography (RIP). Methods: We conducted an observational longitudinal study in hospitalized adults with AECOPD. Respiratory inductance plethysmography signals were recorded daily over four consecutive days using thoracic and abdominal RIP belts. Five-breath sequences were analyzed to derive GPD, phase angle, and loop rotation direction through automated MATLAB processing. Clinical data included demographics, lung function, blood gases, dyspnea severity, and need for intermediate respiratory care unit (IRCU) admission. Temporal changes in TAA indices and subgroup differences (FEV₁ < 35%, IRCU admission) were assessed using repeated-measures ANOVA. Results: Twenty-one patients were included. On admission, mean absolute GPD was 49 ± 58°, with larger delays observed in patients with more severe airflow limitation and in those requiring IRCU support. During hospitalization, GPD showed a significant reduction over time (p < 0.05), particularly in these subgroups, indicating progressive improvement in thoraco-abdominal synchrony. Directional analysis of GPD revealed heterogeneous patterns consistent with different underlying mechanical behaviors. Conclusions: Serial assessment of TAA using respiratory bands and GPD provides clinically meaningful information on the evolution of respiratory mechanics during AECOPD hospitalization. This approach may support bedside monitoring and help track patient response to treatment, offering potential value for individualized respiratory management. Full article

Background/Objectives: Molecular hydrogen (H₂), a natural antioxidant, can selectively reduce hydroxyl radicals and peroxynitrite without affecting signaling molecules such as H₂O₂ and NO. In addition, H₂ can inhibit the synthesis of inflammatory cytokines. Human and animal studies have shown that the inhalation of H₂ has a hypotensive effect. In this context, the aim of the present work was to study the effect of H₂ on the baroreflex regulation of blood pressure in rats with experimental monocrotaline-induced pulmonary hypertension (MCT) in vivo and the effects of H₂ on the reactivity of isolated rat aorta with MCT pulmonary hypertension to α₁-adrenoceptor agonists in vitro. Methods: Experiments were performed on male Wistar rats with MCT pulmonary hypertension; animals were placed in plastic chambers aerated with atmospheric air at a rate of 4 L/min with O₂ and CO₂ control. Cages with the rats of the MCT-H₂ and Control-H₂ groups were ventilated with air containing 4% H₂ twice daily for 2 h each. The MCT-Air and Control-Air groups breathed only atmospheric air. The duration of the experiment was 21 days. On day 20, blood pressure and heart rate (HR) were measured in awake animals and the baroreflex response to phenylephrine (PE) and nitroprusside (NP) was tested. In in vitro experiments, we studied the effect of adding H₂ to the perfusion solution on the responsiveness of isolated aortic preparations from MCT and control rats to the α₁-adrenoceptor agonist PE and the vasodilators NP and Acetylcholine. Results: When the effect of H₂ on the baroreflex response to NP (4.5 μg/kg) was examined in awake rats, the increase in HR was 73.1 ± 16.7 beats/min in the MCT-Air group and 48.1 ± 10.2 beats/min in the MCT-H₂ group (p < 0.01). In the Control-H₂ and Control-Air groups, there was a trend towards a lower HR in the Control-H₂ group, but the differences were not significant. No differences in HR response to PE administration were found between any of the experimental groups. Experiments on isolated aortic preparations from MCT rats showed that the addition of H₂ to the perfusion medium resulted in a 30% reduction in the maximal response to PE compared with the MCT group without hydrogen (p < 0.01), and the potency of PE (EC₅₀) decreased threefold (p < 0.05). There was a decrease in tryptase secretion, indicating an anti-inflammatory effect of H₂. Conclusions. The results demonstrate that H₂ inhalation was associated with an attenuated heart rate response to nitroprusside-induced hypotension and reduced vascular reactivity to phenylephrine in rats with pulmonary hypertension. Full article