Changes In Pressure Research Articles

Myeloid-Specific JAK2 Contributes to Inflammation and Salt Sensitivity of Blood Pressure.

Salt sensitivity of blood pressure (SSBP), characterized by acute changes in blood pressure with changes in dietary sodium intake, is an independent risk factor for cardiovascular disease and mortality in people with and without hypertension. We previously found that elevated sodium concentration activates antigen-presenting cells (APCs), resulting in high blood pressure, but the mechanisms are unknown. Here, we hypothesized that APC-specific JAK2 (Janus kinase 2) through STAT3 (signal transducer and activator of transcription 3) and SMAD3 (small mothers against decapentaplegic homolog 3) contributes to SSBP. We performed bulk or single-cell transcriptomic analyses following in vitro monocytes exposed to high salt and in vivo high sodium treatment in humans using a rigorous salt-loading/depletion protocol to phenotype SSBP. We also used a myeloid cell-specific CD11c+ JAK2 knockout mouse model and measured blood pressure with radiotelemetry after N-omega-nitro-L-arginine-methyl ester and a high salt diet treatment. We used flow cytometry for immunophenotyping and measuring cytokine levels. Fluorescence in situ hybridization and immunohistochemistry were performed to spatially visualize the kidney's immune cells and cytokine levels. Echocardiography was performed to assess cardiac function. We found that high salt treatment upregulates gene expression of the JAK/STAT/SMAD pathway while downregulating inhibitors of this pathway, such as suppression of cytokine signaling and cytokine-inducible SH2, in human monocytes. Expression of the JAK2 pathway genes mirrored changes in blood pressure after salt loading and depletion in salt-sensitive but not salt-resistant humans. Ablation of JAK2, specifically in CD11c+ APCs, attenuated salt-induced hypertension in mice with SSBP. Mechanistically, we found that SMAD3 acted downstream of JAK2 and STAT3, leading to increased production of highly reactive isolevuglandins and proinflammatory cytokine IL (interleukin)-6 in renal APCs, which activate T cells and increase production of IL-17A, IL-6, and TNF-α (tumor necrosis factor-alpha). Our findings reveal the APC JAK2 signaling pathway as a potential target for the diagnosis and treatment of SSBP in humans.

The Impact of Meteorological Factors on Stroke Incidence in the Transdanubian Region of Hungary

Cerebrovascular diseases are the leading cause of death and disability. The epidemiological background and predisposing factors have been the basis of many studies. We aimed to assess the effect of seasonal variability and meteorological factors on stroke incidence in Hungary. National and county-level secondary data were assessed for 2018–2019. We identified stroke with ICD codes I60, I61, I62 (hemorrhagic), I63, I65, and I66 (ischemic). The data were obtained from the University of Pécs Clinical Centre (number of patients per day according to sex and disease subtype, n = 1765). Daily average and maximum wind speed [m/s], precipitation [mm], temperature [°C], and frontal effect [warm/cold/mixed/no effect]) were provided by the Hungarian Meteorological Service. We found that 89.92% of the patients were hospitalized for ischemic and 10.08% for hemorrhagic stroke. We observed a significantly higher number of cases in the other months compared to winter (spring: +35.9%; p = 0.007, summer: +59.0%; p = 0.016, autumn: +36.5%; p = 0.01). In autumn, an increase in temperature increased the incidence of stroke (r = 0.210; p = 0.004). Temperature change affected ischemic stroke incidence (r = 0.112; p = 0.003). In contrast, the number of hemorrhagic stroke cases showed a mild but significant negative association with daily temperature change (r = −0.073; p = 0.049). Overall, a 1 °C temperature change compared to the previous day increased the daily number of admissions by 2.9% (p = 0.017). Air pressure change also affected hemorrhagic stroke incidence (r = 0.083; p = 0.025). Changes in temperature and frontal effects can increase the incidence of stroke. Modern forecasting technology can help the healthcare system prepare for possible increased workloads during critical periods.

Numerical Simulation of Secondary Hydrate Formation Characteristics and Effectiveness of Prevention Methods

The exploitation of natural gas hydrates by the pressure reduction method is affected by the decomposition heat absorption effect, and the range of the formation temperature reduction area is expanding. At the same time, the temperature reduction phenomenon is more significant around the production wells under the influence of gas throttling and expansion effects, and hydrate formation will occur under certain temperature and pressure conditions, leading to blockage of effective seepage channels in the reservoir in the region and elevation of seepage resistance, which may affect the output of hydrate decomposition gas. A numerical simulation model is constructed for the purpose of studying the secondary hydrate generation pattern around the well, analyzing the impact of secondary hydrates around wells on the production capacity, and assessing the effectiveness of prevention methods to inform the actual production of hydrates. The results demonstrate that secondary hydrate is typically formed in the near-well area of the upper part of the production well, and the secondary hydrate around the upper part of the production well is the first to be formed, exhibiting the highest saturation peak and the latest decomposition. The formation of the secondary hydrate can be predicted based on the observed change in temperature and pressure, and the rate of secondary hydrate formation is markedly rapid, whereas the decomposition rate, approximately 0.285 mole/d, is relatively slow. Additionally, the impact of secondary hydrates on cumulative gas production is insignificant, and the effect of secondary hydrates on capacity can be ignored. Hot water injection, wellbore heating, and reservoir reconstruction can effectively eliminate secondary hydrates around the well. Reservoir reconstruction represents a superior approach to the elimination of secondary hydrates, which can effectively enhance production capacity while preventing the generation of secondary hydrates.

A retrospective study of the safety and efficacy of peritoneal dialysis catheter placement under combined local infiltration anesthesia and monitored anesthesia care

ObjectiveGiven the lack of global consensus on anesthesia selection for peritoneal dialysis catheter (PDC) placement via open surgery, this study investigates the safety and efficacy of combining local infiltration anesthesia (LIA) with monitored anesthesia care (MAC) in patients with end-stage renal disease (ESRD).MethodsThis retrospective analysis of ESRD patients who underwent open surgical placement of PDC in the Department of Nephrology, the First Affiliated Hospital of the Army Medical University from 1 August 2020 to 31 May 2022. Patients were categorized into two groups based on anesthesia method: LIA group and LIA + MA group. MA was defined as preoperative sedation (0.2–0.7 µg/kg/h) with dexmedetomidine injection (Huidrican trade name, DEX), and intraoperative analgesia with dexrazoxane injection (Garonin trade name, DEZ) as appropriate according to the patients’ pain scores. We compared the general clinical data of the two groups of patients, the changes in blood pressure and heart rate during the whole operation, the intraoperative and postoperative pain, the total duration of the operation and the immediate postoperative complications.ResultsThe study included 123 patients (59 in the LIA + MAC group and 64 in the LIA group). The LIA + MA group exhibited lower pain scores measured by Visual Analogue Scale(VAS) during surgery (skin incision, subcutaneous adipose tissue dissection, anterior fascia, muscle traction, posterior fascia, peritoneum, and catheterization) compared to the LIA group(p<0.05). In terms of surgical incisions, to intraoperative pain scores (VRS), the LIA + MA group showed higher score level I and lower score level II compared to the LIA group (p = 0.002, 0.004, respectively). The LIA + MA group experienced lower postoperative resting pain (NRS) and VAS than the LIA group (p = 0.001,0.003, respectively). The surgical duration for the LIA + MA group was shorter than that of the LIA group (p<0.001). Preoperative systolic and diastolic blood pressures (SBP and DBP) were higher in the LIA + MA group compared to the LIA group (p<0.001,<0.001, respectively). Postoperative heart rate and DBP were lower in the LIA + MA group (p<0.001, 0.004, respectively). The LIA + MA group exhibited greater changes in heart rate, SBP, and DBP during and after surgery compared to the LIA group (p = 0.009, <0.001,<0.001, respectively). In terms of immediate postoperative complications, the proportion of patients requiring analgesics within 24 h post-surgery was significantly lower in the LIA + MA group (p = 0.031).ConclusionOpen surgery for PDC placement under LIA + MAC is both safe and effective.

Drivers of woody dominance across global drylands

Increases in the abundance of woody species have been reported to affect the provisioning of ecosystem services in drylands worldwide. However, it is virtually unknown how multiple biotic and abiotic drivers, such as climate, grazing, and fire, interact to determine woody dominance across global drylands. We conducted a standardized field survey in 304 plots across 25 countries to assess how climatic features, soil properties, grazing, and fire affect woody dominance in dryland rangelands. Precipitation, temperature, and grazing were key determinants of tree and shrub dominance. The effects of grazing were determined not solely by grazing pressure but also by the dominant livestock species. Interactions between soil, climate, and grazing and differences in responses to these factors between trees and shrubs were key to understanding changes in woody dominance. Our findings suggest that projected changes in climate and grazing pressure may increase woody dominance in drylands, altering their structure and functioning.

Способи зниження складності обчислень при розрахунках потокорозподілу в мережах нестисливої рідини при фіксованих коефіцієнтах гідравлічного опору

Based on the analysis of the process of solving the problem of flow distribution calcula-tion in compressible fluid systems, which boils down to finding the root of a nonlinear system of equations using the Newton — Raphson method, methods of reducing the complexity of calculations at the stages of the iterative process are proposed. The studies belong to the class of hydraulic systems for which the total pressure change on the branch elements is a monotonic smooth function of the flow rate G. For the iterations of the Newton-Raphson method, the stages are analyzed: linearization of the nonlinear system of equations, determination of the discrepancy and error estimation, determination of cost growth and obtaining a new iterative cost value. A method and algorithm for determining the discrepancy and estimating the error with linear complexity relative to the number of branches of graph E is proposed. A method of reducing the number of unknowns in the system of flow distribution equations at the stage of forming a system of linear equations based on the use of the nodal convolution method is described. A number of variants of heuristic algorithms for determining the parameter that takes into account the rate of in-crease in costs when forming a new iterative value of costs and their analysis are present-ed.

Testing the Veining Elimination using Pressure Changes and one Type of Additive in a Cold-box-amine Core Mixture

Testing the Veining Elimination using Pressure Changes and one Type of Additive in a Cold-box-amine Core Mixture

Stress Analysis of Radial Compression Disk Based on MATLAB

Elastic mechanics is an important branch of solid mechanics, mainly studies the deformation and internal force of elastic objects under the action of external forces and other external factors, also known as elastic theory. The study object of elasticity is elastomer. The detailed theoretical structure helps us solve more practical engineering problems. We used Matlab software in the data simulation for visualization processing. On the basis of the study of elasticity, this paper explores the stress distribution of the uniform ideal elastic body to the radial compression disk model, and observes the change of the stress of the radial compression disk when the external pressure changes gradually. The expressions of the corresponding stress components , and are obtained by using the theory of normal concentrated force on the boundary of a half plane body. The stress solutions considering the thickness t of the disk are derived. Finally, the drawing software in Matlab software is used to visualize the theoretical derivation results in order to intuitively feel the change of stress. After the data simulation, the data simulation results are compared with the stress analysis results derived from the theoretical deduction, and the conclusion is drawn.

Analysis of interfacial pressure changes of thermally cycled cold shrinkable joints

Analysis of interfacial pressure changes of thermally cycled cold shrinkable joints

Effects of Diesel Pre-Injection Time on Combustion Process and Emission Characteristics of Diesel/Methanol Dual Fuel Engine

ABSTRACT The traditional diesel engine not only causes the reduction of nonrenewable energy but also aggravates environmental pollution. The utilization of renewable fuels in engine can not only effectively reduce the dependence on oil sources but also effectively reduce emissions. As a renewable oxygen-containing fuel with low production cost and widely sourced, methanol holds vast potential for application in engine. The dual-fuel combustion of diesel and methanol has emerged as an important research issue in the internal combustion engine industry. This paper conducted a study on the combustion and emission characteristics of the diesel/methanol dual fuel based on the optical engine test platform and 3D numerical simulation software. The results show that the change in cylinder pressure is relatively small and the heat release rate increases with the advance of diesel pre-injection time. The pre-injection time of diesel mainly affects the mixture distribution of pre-injection diesel, and the mixture is more evenly mixed with the advance of the pre-injection time. The degree of premixed combustion becomes higher, premixed combustion will lead to more rapid combustion, so the peak heat release rate shows an increasing trend. The pre-injection time of diesel is advanced, resulting in a leaner mixture in the early stage, and the fuel is not easy to burn, so CA10 and CA50 are delayed. The soot formation decreases as the mixture becomes more uniform, and the number of pixels of KL factor in each range also decreases. The average temperature in the cylinder is reduced and the NOX shows a decreasing trend with the advance of the pre-injection time. The change in CO generation is relatively small with the advance of pre-injection time.

Morning tiredness and insomnia symptoms are associated with increased blood pressure in midlife women

ObjectivesThe objective of this study was to investigate how blood pressure, sleep architecture, sleep-disordered breathing, body habitus, and levels of serum follicle-stimulating hormone are associated with symptoms of insomnia and sleep quality during menopausal transition. Methods64 healthy premenopausal women (aged 45–47 years) were recruited to the study. Data were collected at baseline and at 10-year follow-up during sleep laboratory and laboratory visits. A sleep questionnaire was used to evaluate sleep quality and insomnia symptoms. Data were analysed using multiple linear and logistic regression with a backward method. ResultsDuring the menopausal transition, a change in insomnia symptoms was associated with a change in morning systolic blood pressure (β = 0.114 (CI95% 0.023–0.205), p = 0.016). At follow-up, at the age of 56, a higher percentage of REM sleep was associated with a lower odds of restless sleep (OR = 0.842 (95 % CI 0.742–0.954), p = 0.007), while both higher systolic and diastolic evening blood pressure was associated with an increased odds of morning tiredness.OR = 1.047 (95 % CI 1.003–1.092), p = 0.034 and OR = 1.126 (95 % CI 1.018–1.245), p = 0.007, respectively. ConclusionsIn healthy midlife women, a change blood pressure is related to the development of insomnia symptoms during menopausal transition. In postmenopausal women, a high evening blood pressure may be associated with morning tiredness and a reduced amount of REM sleep may be perceived as restless sleep.

Interaction of some chalcone derivatives with calcium channels using a theoretical model

For several years, different drugs have been used to treat heart failure, such as digoxin, captopril, spironolactone, milrinone, levosimedam, dobutamine, and others. However, some of these drugs can produce secondary effects such as arrhythmia, cough, hyperkalemia, and others. Analyzing these data, this study aimed to evaluate the interaction of some chalcone derivatives (1-17) with calcium channels using theoretical models. It is important to mention that 7pjx protein, nifedipine, amlodipine, diltiazem, and verapamil were used as theoretical tools in the DockingServer program. The results showed differences in the interaction of chalcone derivatives compared with nifedipine, amlodipine, diltiazem, and verapamil drugs. Other data indicate that the inhibition constant (Ki) for chalcone analog 1 was lower compared with nifedipine, amlodipine, verapamil, and diltiazem. Besides, other results suggest that Ki for compound 11 was lower compared with nifedipine, verapamil, and diltiazem. All these data suggest that chalcone derivatives 1 and 11 could act as calcium channel inhibitors; this phenomenon could be translated into changes in blood pressure through a decrease in calcium intracellular levels. These data suggest that chalcone derivatives 1 and 11 could be good therapeutic alternatives to treat heart failure.

A multimodal characterization of cardiopulmonary resuscitation-associated lung edema

BackgroundCardiopulmonary resuscitation-associated lung edema (CRALE) is a phenomenon that has been recently reported in both experimental and out-of-hospital cardiac arrest patients.We aimed to explore the respiratory and cardiovascular pathophysiology of CRALE in an experimental model of cardiac arrest undergoing prolonged manual and mechanical chest compression (CC). Oxygen delivery achieved during mechanical or manual CC were also investigated as a secondary aim, to describe CRALE evolution under different hemodynamic supports generated during CPR.MethodsVentricular fibrillation (VF) was induced and left untreated for 5 min prior to begin cardiopulmonary resuscitation (CPR), including CC, ventilation with oxygen, epinephrine administration and defibrillation. Continuous mechanical and manual CC was performed alternating one of the two strategies every 5 min for a total of 25 min. Unsynchronized mechanical ventilation was resumed simultaneously to CC. A lung computed tomography (CT) was performed at baseline and 1 h after return of spontaneous circulation (ROSC) in surviving animals. Partitioned respiratory mechanics, gas exchange, hemodynamics, and oxygen delivery were evaluated during the experimental study at different timepoints. Lung histopathology was performed.ResultsAfter 25 min of CPR, a marked decrease of the respiratory system compliance with reduced oxygenation and CO2 elimination were observed in all animals. The worsening of the respiratory system compliance was driven by a significant decrease in lung compliance. The presence of CRALE was confirmed by an increased lung weight and a reduced lung aeration at the lung CT, together with a high lung wet-to-dry ratio and reduced airspace at histology. The average change in esophageal pressure during the 25-min CPR highly correlated with the severity of CRALE, i.e., lung weight increase.ConclusionsIn this porcine model of cardiac arrest followed by a 25-min interval of CPR with mechanical and manual CC, CRALE was consistently present and was characterized by lung inhomogeneity with alveolar tissue and hemorrhage replacing alveolar airspace. Despite mechanical CPR is associated with a more severe CRALE, the higher cardiac output generated by the mechanical compression ultimately accounted for a greater oxygen delivery. Whether specific ventilation strategies might prevent CRALE while preserving hemodynamics remains to be proved.

Provinols™, a Polyphenolic Extract of Red Wine, Inhibits In-Stent Neointimal Growth in Cholesterol-Fed Rabbit.

Background/Objectives: Epidemiological studies indicate a potential correlation between the consumption of polyphenols and a reduced risk of developing cardiovascular disorders. The present study investigates the potential of a red wine polyphenol oral extract, Provinols™, to reduce neointimal hyperplasia following angioplasty in a hypercholesterolemic rabbit model. Methods: New Zealand white rabbits were fed 1% cholesterol-enriched chow for a period of eight weeks prior to the induction of iliac balloon injury and subsequent stent placement. Following the implantation of the stent, Provinols™ (20 mg/kg/day) or an identical placebo was administered orally for a period of four weeks in a randomized manner. Twenty-eight days following the stenting procedure, the arteries were harvested after euthanasia and subjected to histology assignment analysis. Results: The administration of Provinols™ did not result in a statistically significant change in either blood pressure or plasma cholesterol levels. However, Provinols™ treatment led to a notable reduction in the growth of the intima within the stented area, as well as a reduction in the thickness and surface area of the intima. It is of note that treatment with Provinols™ was associated with a reduction in the accumulation of fat within the arteries and a diminished inflammatory response to injury. Conclusions: The findings demonstrate that oral administration of Provinols™ has the potential to reduce in-stent neointimal growth and lipid deposition, likely due to its anti-inflammatory properties in iliac arteries from hypercholesterolemic rabbits. Additionally, these findings provide an evidence-based rationale for the potential therapeutic benefits of plant-derived polyphenols in the prevention of restenosis associated with stent placement.

Endothelial Dysfunction Does Not Occur after Acute, Elevated Homocysteine Exposure of the Lumen of the Iliac Artery of the Anaesthetised Pig

Introduction: Elevated luminal homocysteine has been linked with cardiovascular disease; however, whether there is a direct effect of homocysteine on blood vessel endothelium is not clear. In this study, the acute effect of luminal homocysteine on iliac artery endothelial function was assessed in the anaesthetised pig. Methods: Hyperhomocysteinaemic blood was injected into an occluded segment of the iliac in the anaesthetised pig for 20 min, and the effect on atrial diameter during the occlusion and during the reactive hyperaemia assessed. Results: No significant changes in arterial diameter or pressure were observed during the incubation period at homocysteine concentrations of 10, 20, 40 and 100 µM. There was also no difference in the magnitude of the iliac diameter increase in the response to reactive hyperaemia when the incubation period was completed. Conclusion: There is no evidence of endothelial dysfunction in response to an acute 20-min elevation in homocysteine in an intact conduit artery.

Multi-bandwidth observer-based adaptive robust pressure control for electro-hydraulic brake system with uncertainties and measurement noise

Accurate pressure regulation of electro-hydraulic brake system (EHB) is essential for enhancing braking performance in automobiles. However, component wear and pressure measurement noise can cause model parameters and controlled states to drift, resulting in system chattering. This nonlinear and uncertain state can significantly degrade pressure control performance. Motivated by this, the article presents a controlled state reconstruction-based adaptive robust pressure control technique with noise suppression. Firstly, a reduced dynamics model is established for controller design, which effectively captures the fundamental characteristic of the EHB. Secondly, a multi-bandwidth extended state observer (MBESO) capable of noise suppression is designed to reconstruct controlled states, including unknown disturbances and unmeasured pressure change rates of the EHB. Thirdly, an MBESO-based adaptive robust pressure control technique is introduced, where the control gain and robust factor are updated based on control and observation errors. In addition, the overall performance of the proposed control strategy is analyzed in the frequency domain, and close-loop stability is demonstrated via the Lyapunov method. Finally, the pressure control precision and robustness of the proposed algorithm are validated in both dynamic and static scenarios through sinusoidal and step-response experiments on a hardware-in-loop test bench. The results indicate that the proposed algorithm reduces dynamic pressure-tracking error by up to 62% compared to traditional method under sinusoidal conditions, with steady-state error remaining within 1 bar under step-response conditions.

Acupuncture as Adjuvant Therapy for Glaucoma: Protocol for a Randomized Controlled Trial.

Glaucoma is a chronic progressive optic neuropathy that necessitates lifelong treatment to reduce the decline of the optic nerve. Due to the extended and continuous treatments required for patients, complementary therapies are often considered alongside conventional treatments to enhance the effectiveness of the treatment. Acupuncture has demonstrated the potential to lower intraocular pressure in previous clinical trials, making it a promising glaucoma intervention. The primary objective of this study is to conduct a single-center randomized control trial involving patients with glaucoma. Acupuncture will be evaluated as an adjunctive therapy. The trial aims to explore its effectiveness for glaucoma. In this single-center randomized controlled trial, participants (N=50) with primary open-angle glaucoma will be randomly assigned to the treatment group, receiving ophthalmic acupuncture with "De Qi" sensation, or the control group, receiving minimum acupuncture stimulation on nonophthalmic acupoints. The intervention will consist of weekly acupuncture treatments for a total of 6 sessions. Participants will be assessed at 8 time points, which are baseline, during the intervention (6 times), and at a 3-month follow-up. The primary outcome measure is a change in the intraocular pressure before and after each acupuncture treatment. Secondary outcomes will include measurements of heart rate and blood pressure before and after acupuncture, best-corrected visual acuity, visual field, optical coherence tomography, optical coherence tomography angiography, the Glaucoma Symptom Scale, and the Glaucoma Quality of Life-15 questionnaire. Recruitment of participants for the trial commenced on June 28, 2023. A total of 10 participants have been enrolled to test the feasibility of the experiment. We anticipate that the preliminary data from this trial will be completed by December 2025. This trial uses rigorous methodology and comprehensive outcome measurements to assess the clinical efficacy of acupuncture as an adjunctive therapy for glaucoma, providing valuable insights for future clinical treatment guidelines. ClinicalTrials.gov NCT05753137; https://clinicaltrials.gov/study/NCT05753137. DERR1-10.2196/57888.

CAUSES OF PAIN IN THE MUSCLES OF THE LOWER EXTREMITIES IN CHILDREN WITH CEREBRAL PALSY

A high level of muscle spasticity in children with cerebral palsy is one of the causes of degenerative and dystrophic changes in tissues. Against the background of high spasticity, there is a violation of blood flow in the vessels of the lower extremities, which leads to changes in subfascial pressure and the formation of primary pain syndromes. The analysis of the literature shows the need to study the issues related to the mechanism of formation of changes in the muscles and determine the primary causes of pain. Objective. Тo study the mechanism of changes in the muscles of the lower extremities, as well as the primary causes of pain syndrome. Methods. The analysed indicators were obtained during the treatment of 40 patients with cerebral palsy, who were divided into 3 groups depending on the muscle tone disorder. Clinical and instrumental methods were used to examine patients. The data obtained were statistically processed with the determination of M ± m, the coefficient of reliability according to Student’s criteria. Results. According to the results of the study, high spasticity leads to impaired blood flow and increased subfascial pressure in the musculofascial sheaths. There is an inverse correlation between the increase in subfascial pressure, the diameter of the vessel lumen and blood flow velocity. This is one of the causes of degenerative and denervation changes in muscles and fascia. It was proved that the occurrence of primary pain in the lower extremities is caused by various etiological causes: tissue ischemia; increased subfascial pressure; narrowing of pathologically significant anatomical areas in which nerves lie; degenerative and dystrophic changes in the joints. Conclusions. The study found that the cause of changes in the muscles and fascia is a violation of blood flow, a change in subfascial pressure in the musculofascial cases of the lower extremities. The occurrence of pain in the lower extremities in children with cerebral palsy is multifactorial in nature and consists of myofascial, articular, and tunnel syndromes.

A pilot study of thecardiopulmonary effects in healthy volunteers after exposure to high levels of PM2.5 in a New York City subway station.

Subway systems are becoming increasingly common worldwide transporting large populations in major cities. PM2.5 concentrations have been demonstrated to be exceptionally high when underground, however. Studies on the impact of subway PM exposure on cardiopulmonary health in the United States are limited. Healthy volunteers in New York City were exposed to a 2-h visit on the 9th Street Station platform on the Port Authority Trans-Hudson train system. Blood pressure, heart rate variability (HRV), spirometry, and forced impulse oscillometry were measured, and urine, blood spot, and nasal swab biosamples were collected for cytokine analysis at the end of the 2-h exposure period. These endpoints were compared against individual control measurements collected after 2-h in a "clean" control space. In addition to paired comparisons, mixed effects models with subject as a random effect were employed to investigate the effect of the PM2.5 concentrations and visit type (i.e., subway vs. control). Mean PM2.5 concentrations on the platform and during the control visit were 293.6 ± 65.7 (SD) and 4.6 ± 1.9µg/m3, respectively. There was no change in any of the health metrics, but there was a non-significant trend for SDNN to be lower after subway exposure compared to control exposure. Total symptomatic scores did increase post-subway exposure compared to reported values prior to exposure or after the control visit. No significant changes in cytokine concentrations in any specimen type were observed. Mixed-effects models mostly corroborated these paired comparisons. Acute exposures to PM on a subway platform do not cause measurable cardiopulmonary effects apart from reductions in HRV and increases in symptoms in healthy volunteers. These findings match other studies that found little to no changes in lung function and blood pressure after exposure in underground subway stations. Future work should still target potentially more vulnerable populations, such as individuals with asthma or those who spend increased time underground on the subway such as transit workers.

The physiological determinants of symptom burden in cirrhosis with ascites.

Paracentesis is commonly used to manage patient discomfort due to ascites. The relationship between ascites pressure, ascites volume, and patient discomfort has not been elucidated. We prospectively enrolled adult patients with non-malignant ascites undergoing outpatient therapeutic paracenteses from 2021 to 2024 at a tertiary care hospital. Patients completed a validated symptom questionnaire (ASI-7, maximum score 35) before, immediately after, and 1week after paracentesis. An open-ended manometer was used to measure ascites pressure at the beginning and end of paracentesis. Mixed effect linear regression was performed to evaluate the relationships between patient characteristics, pressure, volume, and symptoms. One hundred and fifty paracentesis procedures among 48 unique patients with an average Model for End Stage Liver Disease-Sodium 3.0 of 16.7 were included. An average of 6.5L was drained, which reduced abdominal pressure from a mean of 13.7 to 6.0cm H2O (10.1 to 4.4mmHg, p<0.001) and mean symptom score from 22.6 to 6.5 (p<0.001). Regression models identified that symptoms and abdominal pressure linearly correlated above a pressure of 6cm H2O or ASI-7 score of 16 (p<0.01). Taller patients required about 670ml additional drainage per inch above the cohort mean height (5'8″) to achieve the same symptom relief. Pressure measured at the bedside can be used to explore changes in abdominal pressure during paracentesis. Pressure, volume, and patient level factors such as height contribute to patient symptoms but cannot fully explain discomfort associated with ascites and relief after paracentesis.