Search Results (450)

Soil hypoxia caused by waterlogging severely restricts kiwifruit growth, and screening waterlogging-tolerant rootstocks and analyzing their mechanisms are of great significance for industrial development. In this study, waterlogging-tolerant Actinidia valvata ‘Shuixiu’ was used as the test material and Actinidia chinensis ‘Hongyang’ as the control. Waterlogging stress was simulated artificially, and physiological measurements combined with transcriptome sequencing were used to explore its waterlogging tolerance regulatory characteristics based on respiratory metabolism. The results showed that the waterlogging tolerance of ‘Shuixiu’ was significantly better than that of ‘Hongyang’. It upregulated sucrose synthase and α/β-amylase genes and inhibited the continuous up-regulation of trehalose-6-phosphate synthase genes, leading to significant accumulation of glucose-6-phosphate, a key glycolytic substrate. Some members of glycolytic key gene families, such as glucose-6-phosphate isomerase and phosphofructokinase, were upregulated in ‘Shuixiu’, which increased phosphoglycerate kinase activity and accumulated 3-phosphoglyceric acid and pyruvate, ensuring efficient conversion of carbon sources to ATP. Some members of core tricarboxylic acid cycle gene families, such as pyruvate dehydrogenase and citrate synthase, were upregulated in ‘Shuixiu’, with significantly higher pyruvate dehydrogenase activity and acetyl coenzyme A content, maintaining partial aerobic respiration capacity. Some members of the alanine transaminase gene family were upregulated in ‘Shuixiu’ to enhance alanine fermentation, resulting in a significant reduction in root ethanol accumulation. This study clarified the core respiratory metabolic regulatory characteristics of kiwifruit in response to waterlogging and provided key targets and a theoretical basis for molecular breeding of waterlogging-tolerant rootstocks. Full article

Glyphosate is a widely used herbicide with increasing concern regarding its non-target impacts in coastal ecosystems and mariculture species. Here, we profiled acute physiological stress signatures of waterborne glyphosate exposure in the sea cucumber Apostichopus japonicus, integrating measured exposure concentrations, tissue residues, digestive and oxidative/innate immune biomarkers, and gut microbiota. After 24 h exposure, measured waterborne glyphosate confirmed the intended gradient (0.09 ± 0.02, 1.26 ± 0.09, and 4.49 ± 1.12 mg/L for low-, medium-, and high-dose treatments, respectively), and overt stress phenotypes with mortality occurred only at the high dose (36.67%), enabling separation of high-dose survivors (HS) and high-dose dead (HD) for downstream analyses. Tissue measurements showed low/background levels in controls, with compartment-specific distribution: the respiratory tree exhibited higher burdens at the medium dose, whereas coelomic fluid showed the highest burdens in HS at the 24 h endpoint. Functionally, most intestinal digestive enzymes were unchanged, but trypsin activity was consistently suppressed across exposed groups (p < 0.05). In coelomic fluid, oxidative stress responses were evident, with elevated MDA (L and M), reduced CAT (L, M, and HS), and reduced GSH-PX in HS (all p < 0.05), while SOD, GR, and lysozyme showed no significant changes. Gene sequencing of 16S rRNA (n = 3 per group) revealed significant shifts in community diversity/evenness (Shannon p = 0.0497; Simpson p = 0.0484) and beta diversity (PCo1 = 30.08%, PCo2 = 26.30%; PERMANOVA F = 1.816, p = 0.008), with LEfSe indicating discriminative taxa associated with exposure/outcomes. Collectively, these multi-level endpoints define an acute glyphosate stress signature in A. japonicus, linking internal dose distribution to oxidative disruption, impaired intestinal proteolysis, and microbiome restructuring. Full article

Pomacea canaliculata, as a significant invasive alien species, poses severe threats to agricultural development. Currently, chemical applications demonstrate notable efficacy in controlling this pest. However, metaldehyde exhibits overly singular toxicity towards P. canaliculata; niclosamide sulfate is not a molluscicide; and fentin acetate is a fungicide. Currently, these findings fail to elucidate the physiological and biochemical effects of the compounds after they enter the P. canaliculata’s body. In this study, we evaluated the toxicity of metaldehyde (ME), niclosamide sulfate (NS), and fentin acetate (FA) against P. canaliculata and analyzed the morphological and physiological changes in response to chemical stress. The results indicated that three chemicals exhibited potent molluscicidal activity, especially in the NS treatment group. After 12 h exposure to LC₅₀ concentrations (48 h LC₅₀), the surface area of livers was reduced significantly by 12.1%, 13.9%, and 2.8% compared to the control group, while the kidneys expanded significantly by 6.4%, 3.2%, and 16.7%, respectively. The heart showed marked enlargement by 152.1% and 44.2% under niclosamide sulfate and metaldehyde treatments. The pulmonary sac significantly contracted by 23.6% under niclosamide sulfate stress but expanded by 6.1% under fentin acetate exposure. The stomach enlarged significantly after niclosamide sulfate treatment, whereas it shrank by 2.1% and 5.7% under metaldehyde and fentin acetate treatments, respectively. Metabolomic analysis of liver tissues revealed 553, 99, and 585 differential metabolites compared to the control group, respectively. KEGG pathway enrichment analysis showed that the metabolism pathway, lysine degradation, and bile secretion are likely related to the response to chemical stress in P. canaliculata. Further examination showed a significant decrease in total protein content and the activities of malondialdehyde (MDA), acetylcholinesterase (AChE), superoxide dismutase (SOD), and catalase (CAT) under chemical stress. These findings enhance our understanding of the targeted mechanisms of molluscicides against P. canaliculata. Metaldehyde may exert neurotoxic effects on the P. canaliculata, while niclosamide sulfate may interfere with its respiratory system. Additionally, both chemicals affect metabolic pathways in the snail’s liver, including lipid metabolism and metabolic pathways associated with energy metabolism. These findings provide valuable insights for designing a novel snail control agent and formulating scientific management strategy. Full article

The co-occurrence of ammonia nitrogen and hypoxia represents a physiologically taxing synergistic challenge for benthic bivalves—as it forces a conflict between the high energy demand for detoxification and the limited energy supply under low oxygen, yet the tissue-specific strategies underlying their resilience remain poorly understood. This study investigated the physiological and transcriptomic responses of the razor clam Sinonovacula constricta to ammonia (AG), hypoxia (HG), and their combination (HAG) over 96 h. Transcriptomic profiling revealed that the gill and hepatopancreas employ distinct, organ-coordinated adaptive strategies rather than a uniform systemic response. The gill prioritized respiratory homeostasis by fine-tuning oxygen sensing: transcriptional suppression of hypoxia-inducible factor 1-α (HIF-1α) (to limit glycolytic acidosis) was followed by a chronic induction of HIF-2α, alongside the specific upregulation of the mitochondrial respiratory gene cytochrome c oxidase-6b (COX-6b). In contrast, the hepatopancreas executed a critical metabolic trade-off centered on arginine metabolism. Under combined stress, arginine flux was redirected toward the urea cycle via a robust upregulation of arginase (ARG) for detoxification, while nitric oxide synthase (NOS) was concurrently suppressed. This reciprocal regulation suggests a strategy to prioritize ammonia clearance and energy conservation at the expense of immune signaling. These findings elucidate how S. constricta navigates the bioenergetic conflict between detoxification and oxygen limitation, providing molecular targets for breeding stress-resistant aquaculture strains. Full article

Oxygen therapy is one of the most widely used interventions in critical care, yet it remains poorly individualized. Recent trials and meta-analysis suggest no mortality difference between conservative and liberal oxygen strategies, reinforcing the perception that dose does not matter within usual ranges. From this perspective, we argue that this apparent neutrality may largely reflect methodological and conceptual limitations, although true clinical equivalence in some patient populations remains plausible and cannot be excluded based on current evidence. Heterogeneous populations, overlapping oxygenation targets, and the absence of exposure metrics (time in hyperoxia, time in hypoxemia, and cumulative partial pressure of arterial oxygen/peripheral oxygen saturation curves) dilute phenotype-specific signals and force distinct physiological responses into a single pooled estimate. We propose a conceptual model in which oxygen behaves as a dose-dependent, time-dependent drug with phenotype-specific therapeutic windows, particularly in chronic hypercapnia, traumatic brain injury, sepsis, and early versus late acute respiratory distress syndrome. Building on this model, we outline a methodological agenda for precision oxygen trials: defining interventions by actual exposure, pre-specifying pathophysiological subgroups, adopting patient-centered core outcome sets, and using adaptive, target-range designs and individual patient data meta-analyses. For contemporary guidelines and research, the key question is no longer whether conservative or liberal oxygen therapy is superior on average, but how to match the right oxygenation range to the right intensive care unit phenotype at the right time. Moving from population-averaged comparisons to exposure-aware, phenotype-oriented strategies is essential if oxygen therapy is to become a truly precision intervention in critical care. Full article

Objectives: Diuretics are frequently used in bronchopulmonary dysplasia (BPD), yet evidence describing their short-term physiological effects remains limited. This study aimed to describe early changes in respiratory support parameters and safety outcomes following combined oral spironolactone and hydrochlorothiazide (SP/HCTZ) therapy in preterm infants with BPD. Methods: A retrospective, single-center before–after observational study was conducted. Preterm infants diagnosed with BPD who initiated SP/HCTZ therapy were included. Respiratory parameters (FiO₂, PEEP, and flow rate) and serum electrolytes were compared between Day 1 (initiation) and Day 3 of treatment. A predefined clinical response was defined as either a ≥10% reduction in FiO₂ or a step-down in respiratory support modality. Results: Fifty-six infants (mean gestational age 27.7 ± 2.3 weeks) were analyzed. After 72 h of SP/HCTZ therapy, mean FiO₂ decreased from 26.2 ± 6.3% to 22.4 ± 3.4% (p < 0.001). Significant reductions were also observed in PEEP and cannula flow rates (p = 0.004 and p = 0.003, respectively). Overall, 39 infants (69.6%) met the predefined clinical response criteria. The prevalence of hyponatremia (Na < 133 mmol/L) increased from 7.1% at baseline to 25.0% on Day 3 (p = 0.039). Conclusions: Initiation of SP/HCTZ was temporally associated with short-term reductions in respiratory support parameters; however, these findings should be interpreted as associations rather than treatment effects. Given the increased frequency of hyponatremia by Day 3, close electrolyte monitoring appears warranted during the early phase of therapy. Full article

Chronic obstructive pulmonary disease (COPD) is a major contributor to global respiratory morbidity and exhibits substantial sex- and gender-related differences in incidence, phenotype, pathophysiology, and outcomes across the life course. Historically regarded as a predominantly male disease due to higher smoking rates, COPD is now increasingly recognized among women, reflecting changing exposure patterns and enhanced diagnostic attention. Moreover, evidence indicates that women may be more biologically susceptible to the harmful effects of tobacco smoke and often develop COPD at younger ages. Clinical manifestations also differ, with women more frequently reporting dyspnea, anxiety, and depression, whereas men may exhibit more cough and sputum production. Imaging studies suggest that airway-predominant disease is more common in women, while men are more likely to demonstrate emphysema-predominant patterns. Furthermore, women face an increased risk of exacerbation, yet they are more likely to experience underdiagnosis or misdiagnosis. Treatment responses and comorbidity patterns also show sex- and gender-related variations. Despite these differences, most clinical guidelines and therapeutic strategies do not differentiate by sex and gender, highlighting a gap in personalized COPD management. Overall, growing evidence underscores the importance of incorporating sex and gender as biological and sociocultural variables in COPD research, diagnosis, and treatment. Recognizing sex/gender-specific risk profiles, symptom patterns, and disease phenotypes may improve early detection and enable more targeted, effective interventions. This narrative synthesis, derived from a meticulous search in PubMed and the critical selection of 74 articles from the 448 identified originally, integrates evidence from guideline statements, registry studies, mechanistic and preclinical research, imaging and physiology investigations, systematic reviews, and randomized controlled trials that report sex- and gender-disaggregated data. Full article

Circadian rhythm regulates several physiological functions, and influences endocrine and metabolic responses in mammals, with cortisol acting as important modulator of this mechanism. Cortisol secretion is affected by both internal and external factors and is intensified under stress conditions. The response to surgical stress is consistently observed after surgical procedures, such as ovariohysterectomy (OVH). Therefore, this study aimed to evaluate the influence of the circadian rhythm on the surgical stress response following elective OVH in healthy bitches. Twenty patients weighing between 10 and 20 kg were hospitalized 48 h before surgery and remained hospitalized for 48 h postoperative. The animals were randomly allocated into two groups and underwent OVH either in the morning (6–8 h—a.m., GAM) or at night (18–20 h—p.m., GPM). Surgical procedures were standardized with respect to the surgical team, technique applied and duration; this was carried out in order to induce a comparable level of surgical stress. Physical parameters (systolic blood pressure, heart rate, respiratory rate and rectal temperature) and laboratorial analyses (cortisol, leukogram, protein thiols, no protein thiols, vitamin C, ferric reducing ability of plasma and thiobarbituric acid reactive substances) were assessed immediately before surgery and at 2, 4, 6, 12, 24 and 48 h, as well as 14 days postoperatively. No significant changes in cortisol profile were detected. However, significant alteration in the respiratory rate, rectal temperature, time to first urine, and lipid peroxidation were observed in the GPM group, suggesting that surgeries performed at night induce greater disturbances in homeostasis than those performed in the morning. Full article

Background: Following the earthquakes that occurred in Türkiye in 2023, the resulting demolition dust (DD) negatively impacted air quality and led to an increase in respiratory diseases. Although the harmful effects of crystalline and amorphous silica are known, the effects of hydrated cement dust (HCD), autoclaved aerated concrete dust (AACD), and DD on the lungs have not been sufficiently investigated. This rat study presents the first experimental data on the toxicity of these dusts. Methods: In the study, the structural properties of dust particles smaller than 5 µm were characterized using XRD analysis. Subsequently, 48 female rats were divided into four groups: HCD, AACD, DD, and control. The relevant dust suspensions were administered to the experimental groups, and physiological saline was administered to the control group intranasally a total of five times over a 15-day period, once every 3 days. Subsequently, bronchoalveolar lavage fluid, blood, and lung tissues were analyzed. Results: An increase in emphysema was observed in all exposure groups, and this increase was significant in the AAC and HC groups. Inflammation and alveolar wall thickness increased in the HC and DD groups. Goblet cell hyperplasia was detected only in the HC group; increases in CD68⁺ macrophages and TGF-β, as well as elevated hydroxyproline, were detected only in the DD group and supported the fibrotic response (p < 0.05). Neutrophil increase was specific to the AAC group. In all exposure groups, Akt/NF-κB pathway proteins, caspase-9, and MPO levels increased, while Bcl-xl levels decreased (p < 0.05). The findings indicate that the examined dusts trigger inflammation and apoptosis. Conclusion: Exposure to HCD, AACD, and DD causes lung damage by modulating the Akt/NF-κB signaling cascade; it enhances the apoptotic process through Bcl-xl suppression and caspase-9 increase. DD also induces a marked fibrotic response. Full article

Kiwifruit, classified as a respiratory climacteric fruit, faces challenges due to its limited resistance to storage and transportation. Although low-temperature storage is a cost-effective and widely used method, the cold injury it induces poses significant hurdles to industrial development. In this study, we selected ‘Taishan 1’, the dominant kiwifruit cultivar in Shandong Province, as the experimental material. Through transcriptome sequencing, we identified the key gene AcMYC2, which plays a crucial role in the kiwifruit’s response to low-temperature stress. Subsequently, virus-induced gene silencing (VIGS) was performed on ‘Taishan 1’ kiwifruit, and gene overexpression was validated in tomatoes. The results demonstrated that AcMYC2 enhances cold tolerance in kiwifruit accompanied by multiple physiological processes, including antioxidant activity, lipid metabolism, and cell wall degradation. These findings offer significant insights into mitigating cold injury during low-temperature storage of kiwifruit and provide a theoretical foundation for advancing postharvest preservation techniques. Full article

Background: The purpose was to determine the ventilatory and metabolic demands in percentage-based heart rate (HR) zones in active-duty firefighters. Methods: Male career firefighters (n = 48, 38.17 ± 9.02 years, 1.79 ± 0.05 m, 88.27 ± 12.50 kg) completed a maximal treadmill test while wearing chest strap monitors to measure physiological responses corresponding to Zone 1 (50–59%), Zone 2 (60–69%), Zone 3 (70–79%), Zone 4 (80–89%), and Zone 5 (90–100%) based on age-predicted maximal HR. Aerobic capacity (VO_2PEAK, mL·kg⁻¹·min⁻¹), average minute ventilation (V_E, L·min⁻¹), and respiratory exchange ratio (RER) in each zone was measured via indirect calorimetry. Linear mixed models determined significant differences in V_E, RER, and time in zone (min). Results: Significant relationships emerged between VO_2PEAK and average RER in Zone 5 (r = −0.33) and time in Zone 3 (r = 0.45), Zone 4 (r = 0.41), and Zone 5 (r = 0.41). A significant HR zone effect emerged in V_E (F = 516.01, p < 0.001) indicating that V_E increased as zone intensity increased. After controlling for VO_2PEAK, a significant HR zone effect emerged in RER (F = 11.90, p < 0.001), indicating that average RER increased as zone intensity increased. No HR zone effect was found for time in zone (F = 1.18 p = 0.332) after controlling for VO_2PEAK. Conclusions: A practical cardiovascular workload measure, such as percentage-based HR zones determined from treadmill testing, have distinct ventilatory and metabolic responses. Higher aerobic capacity is related to greater time spent working in higher HR zones. Full article

Antibiotics remain pillars of modern medicine, yet the mechanisms underlying bacterial killing remain incompletely understood. This review addresses unresolved questions in antibiotic lethality, focusing on poorly defined cell-level events. How coinciding stress responses combine to drive killing, and how cells prioritise protective pathways are unclear. Metabolic state strongly modulates lethality, as growth rate, nutrient availability, and respiratory activity determine whether damage reaches a fatal threshold. A small subpopulation of genetically identical cells persists through treatment, but the signals governing entry and maintenance of this state remain elusive. The contribution of reactive oxygen species is context-dependent and debated. Species-specific differences in autolysin activation during cell wall targeting lack unifying principles, while ribosome-targeting antibiotics also induce secondary membrane perturbations whose mechanistic links to translation arrest are unresolved. Biofilms further complicate killing by limiting drug penetration and slowing growth, and host factors such as oxygen tension, pH, and immune pressure reshape bacterial responses in ways that are only beginning to be understood. Addressing these blind spots may reveal new vulnerabilities in bacterial physiology and guide the development of therapeutic strategies that improve killing while limiting tolerance and persistence. Full article

Background/Objectives: Physiological changes during hyperbaric oxygen therapy (HBOT) are not well characterized, particularly in non-emergent patients receiving HBOT as part of a repeated or maintenance treatment course, in whom understanding physiological responses during individual sessions is important for clinical monitoring. This study evaluated changes in vital signs and electrocardiographic (ECG) findings across the pre-compression, compression, maintenance, decompression, and post-treatment phases and evaluated clinical symptoms. Methods: This prospective observational study enrolled 50 hemodynamically stable non-emergent patients undergoing HBOT at a single tertiary center. Changes in vital signs and ECG findings were recorded across all phases. Repeated vital sign measurements were analyzed using linear mixed models; ECG abnormalities were assessed using generalized linear mixed models. Results: Heart rate decreased significantly across all HBOT phases compared with baseline. Blood pressure (BP) remained stable during compression and maintenance but increased significantly during decompression and post-treatment. Respiratory rate decreased during treatment and then returned to baseline. Oxygen saturation remained within normal ranges throughout all phases. Transient ECG rhythm abnormalities were observed in 10.0% of patients, primarily during compression and maintenance phases. One patient developed brief clinical symptoms accompanied by supraventricular tachycardia immediately after decompression, which resolved spontaneously without intervention. No significant oxygen toxicity or serious adverse events were observed. Conclusions: HBOT in hemodynamically stable non-emergent patients induces predictable, largely transient physiological changes and is well tolerated under standard protocols. Blood pressure elevation was most pronounced during decompression and the post-treatment phase, whereas transient ECG abnormalities were observed primarily during the compression and maintenance phases, with a single episode of supraventricular tachycardia occurring immediately after decompression. These findings provide foundational clinical data for understanding phase-specific physiological responses during HBOT and inform future studies in higher-risk patient populations. Full article

Background: This study aimed to identify factors influencing non-invasive ventilation (NIV) outcomes in patients with hypercapnic respiratory failure due to various respiratory conditions in a resource-limited intensive care unit (ICU) setting. These predictors can guide us in the prompt decision of ventilation, resulting in better outcomes. Methods: Patients requiring NIV for hypercapnic respiratory failure of any cause were included. Arterial blood gases were measured at 1 and 24 h, and an improvement in pH ≥ 7.35 was taken as a cut-off for early and late physiological responses, respectively. Binary regression analysis was used to identify predictors of physiological response, need for mechanical ventilation, and mortality. Results: Among 226 patients (139 males), the underlying causes were obstructive (71%), restrictive (25%), and infective disorders (4%). Older age, higher one-hour PCO₂, FiO_2, and respiratory rate were associated with increased mortality. Late physiological response correlated with higher IPAP and WBC counts, while higher WBC counts also predicted need for mechanical ventilation on binary logistic regression. Conclusions: Higher one-hour PCO₂, older age, higher FiO₂, respiratory rate, WBC count, and IPAP predicted an unfavorable outcome of NIV in acute hypercapnoic respiratory failure. Locally generated data can support timely escalation to mechanical ventilation and inform patient selection for initial NIV therapy in resource-limited settings. Full article

The overdose mortality landscape has shifted from predominantly opioid exposures to a polysubstance epidemic increasingly driven by illicit fentanyl and fentanyl analogs combined with other centrally active agents. Among the co-intoxicants, veterinary α₂-adrenoceptor (α₂AR) agonists such as xylazine have emerged as clinically confounding adulterants. Recent reports from forensic toxicology, medical examiners, and border/interdiction agencies indicate that medetomidine, a veterinary sedative racemate with the highly selective α₂AR agonist enantiomer dexmedetomidine, is increasingly being detected together with fentanyl and its analogs in seized materials and postmortem assays. Prior reviews have covered these aspects. The current review synthesizes current evidence and clinical experience relevant to fentanyl + medetomidine co-exposure-induced respiratory depression—a primary cause of death. We focus on convergent µ-opioid receptor (MOR) and α₂AR signaling within key physiological substrates, including respiratory rhythm-generating networks, ascending arousal pathways, chemosensory reflex control of ventilation, and autonomic cardiovascular regulation, integrating mechanistic pharmacology, respiratory and cardiovascular toxicology, emergency-room treatment, and emerging public-health implications. Available evidence supports a model in which combined MOR and α₂AR activation produces additive-to-synergistic suppression of ventilation and consciousness, attenuation of hypoxic ventilatory drive and CO₂ responsiveness, with marked sympatholysis manifested as bradycardia and hypotension, all of which can persist beyond presumptive opioid reversal with a MOR antagonist. We discuss the implications for prehospital and emergency care. In sum, the increasing detection of medetomidine in the illicit fentanyl supply represents an emerging and potentially high-risk co-exposure pattern that may be only partially naloxone-responsive. Lastly, we highlight potential future pharmacologic countermeasures for polysubstance overdose, such as the BK-channel antagonist ENA-001, which may address naloxone-insensitive ventilatory suppression in opioid-dominant polysubstance overdose. Full article