Rate Of Contraction Research Articles

Effects of Matricaria aurea extract in excisional wound healing on albino rats

The Asteraceae herbal plant Matricaria aurea (Loefl.) Sch.Bip is well known for its use in treating gastrointestinal, cardiac, pulmonary, rheumatologic and many other ailments; nevertheless, wound care has not yet received scientific validation. This study was done to evaluate the efficacy of M. aurea topical formulation on the rate of wound healing and contraction and the histopathological properties of the healing tissue in a rat model of an excisional wound. A total of 45 male rats with excisional wounds were enrolled in the study. The rats were divided into three groups, each with 15 male rats weighing approximately 200–250 g. The first group received treatment with M. aurea, the second group received fusidic acid cream and the third group received normal saline. The treatment was administered for 15 days while photographs were taken every other day, the diameters were measured and a histopathologic examination was conducted. There was a significant accelerated effect for wound healing, as evidenced by the inflammatory cells and diameters reducing to almost the same degree in the M. aurea and fusidic acid groups as compared to the control group (p<0.05). In vivo, the healing of wounds in albino Wister rats is demonstrated by the ethanolic extract of M. aurea. The findings, which show enhanced contraction, epithelization and tensile strength, significantly imply that wound healing promotion and acceleration can be achieved based on faster healing as compared to negative control and similar to standard control (fusidic acid) wounds.

Spectral bounds on the entropy flow rate and Lyapunov exponents in differentiable dynamical systems

Abstract Some microscopic dynamics are also macroscopically irreversible, dissipating energy and producing entropy. For many-particle systems interacting with deterministic thermostats, the rate of thermodynamic entropy dissipated to the environment is the average rate at which phase space contracts. Here, we use this identity and the properties of a classical density matrix to derive upper and lower bounds on the entropy flow rate with the spectral properties of the local stability matrix. These bounds are an extension of more fundamental bounds on the Lyapunov exponents and phase space contraction rate of continuous-time dynamical systems. They are maximal and minimal rates of entropy production, heat transfer, and transport coefficients set by the underlying dynamics of the system and deterministic thermostat. Because these limits on the macroscopic dissipation derive from the density matrix and the local stability matrix, they are numerically computable from the molecular dynamics. As an illustration, we show that these bounds are on the electrical conductivity for a system of charged particles subject to an electric field.

Evaluation of Dermal Wound Healing Potential: Phytochemical Characterization, Anti-inflammatory, Antioxidant, and Antimicrobial Activities of Euphorbia guyoniana Boiss. & Reut. Latex.

This study investigates the wound-healing potential of Euphorbia guyoniana latex (EGL) in male Wistar rats, along with its biochemical composition and biological activities. Phytochemical analysis identified moderate levels of phenolics, flavonoids, and tannins, with HPLC revealing five phenolic compounds. EGL demonstrated strong antioxidant activity in DPPH assays, surpassing ascorbic acid in protecting red blood cells. Its performance in the ß-carotene-linoleic acid assay was robust, though its FRAP assay results were weaker. EGL also exhibited significant anti-inflammatory activity, comparable to Acetylsalicylic acid, and showed antibacterial effects against Listeria innocua. In Vivo, EGL-infused ointments accelerated wound healing, reducing epithelialization periods to 12-16 days, with a higher wound contraction rate compared to controls. The study concludes that EGL, rich in bioactive compounds, holds potential as a promising natural agent for wound healing, owing to its potent antioxidant, anti-inflammatory, and antibacterial properties.

Sucla2 Knock-Out in Skeletal Muscle Yields Mouse Model of Mitochondrial Myopathy With Muscle Type-Specific Phenotypes.

Pathogenic variants in subunits of succinyl-CoA synthetase (SCS) are associated with mitochondrial encephalomyopathy in humans. SCS catalyses the conversion of succinyl-CoA to succinate coupled with substrate-level phosphorylation of either ADP or GDP in the TCA cycle. This report presents a muscle-specific conditional knock-out (KO) mouse model of Sucla2, the ADP-specific beta subunit of SCS, generating a novel invivo model of mitochondrial myopathy. The mouse model was generated using the Cre-Lox system, with the human skeletal actin (HSA) promoter driving Cre-recombination of a CRISPR-Cas9-generated Sucla2 floxed allele within skeletal muscle. Inactivation of Sucla2 was validated using RT-qPCR and western blot, and both enzyme activity and serum metabolites were quantified by mass spectrometry. To characterize the model invivo, whole-body phenotyping was conducted, with mice undergoing a panel of strength and locomotor behavioural assays. Additionally, exvivo contractility experiments were performed on the soleus (SOL) and extensor digitorum longus (EDL) muscles. SOL and EDL cryosections were also subject to imaging analyses to assess muscle fibre-specific phenotypes. Molecular validation confirmed 68% reduction of Sucla2 transcript within the mutant skeletal muscle (p < 0.001) and 95% functionally reduced SUCLA2 protein (p < 0.0001). By 3 weeks of age, Sucla2 KO mice were 44% the size of controls by body weight (p < 0.0001). Mutant mice also exhibited 34%-40% reduced grip strength (p < 0.01) and reduced spontaneous exercise, spending about 88% less cumulative time on a running wheel (p < 0.0001). Contractile function was also perturbed in a muscle-specific manner; although no genotype-specific deficiencies were seen in EDL function, SUCLA2-deficient SOL muscles generated 40% less specific tetanic force (p < 0.0001), alongside slower contraction and relaxation rates (p < 0.001). Similarly, a SOL-specific threefold increase in mitochondria (p < 0.0001) was observed, with qualitatively increased staining for both COX and SDH, and the proportion of Type 1 myosin heavy chain expressing fibres within the SOL was nearly doubled (95% increase, p < 0.0001) in the Sucla2 KO mice compared with that in controls. SUCLA2 loss within murine skeletal muscle yields a model of SCS-deficient mitochondrial myopathy with reduced body weight, muscle weakness and exercise intolerance. Physiological and morphological analyses of hindlimb muscles showed remarkable differences in exvivo function and cellular consequences between the EDL and SOL muscles, with SOL muscles significantly more impacted by Sucla2 inactivation. This novel model will provide an invaluable tool for investigations of muscle-specific and fibre type-specific pathogenic mechanisms to better understand SCS-deficient myopathy.

Cost per kilogram weight-lost - Lifestyle change program at the Public Health Institute in Croatia

Abstract According to the 2019 European Health Survey, 42% and 23% of the Croatian adult population were affected by overweight or obesity, respectively. Counselling services are available in some Public Health Institutes for free or paid out-of-pocket. The estimated cost per kilogram lost in programs in Europe and the USA ranges from 100-340€, with a justifiable cost estimation for a weight loss intervention being 120-210€. Aim was to demonstrate the cost of losing one kilogram by analysing necessary initial material and human resources, including equipping counselling centres, and estimating the cost of continuous implementation. In the year 2023, 47 participants (31F,10M) with a BMI higher than 30 kg/m2 enrolled in the three-month free Program in the County Public Health Institute in Pozega. The program consisted of personalized assessment, habit change plan, education, counselling and follow-up. An analysis of the minimal required equipment and working hours of physician and a nurse (contracted gross hourly wage rates) was conducted. The main outcome measure was the cost of one kilogram lost by participants at the end of the Program. Program was completed by 41 (22F, 9M) participants (87.2%). Their initial BMI ranged from 30.3 to 47.4 kg/m2. Collectively, they lost 323.2 kg (1.3-24.4kg), with an average of 7.9 kg or 7.4% (1.7-19.8%) of their initial weight lost. The estimated total cost of medical, IT and office equipment, was 9363€. The human resources cost was 9509€, with a specialist and nurse spending 249 and 116 hours, respectively (27.6€/hour and 13€/hour). The initial cost per kilogram lost, including the prerequisites for the work of the counselling centre, was 58.4€. The continuous program cost with equipment already in place is estimated at 27.9€ per kilogram lost. We have shown that the lifestyle management program in the Croatia without extra cost to patients delivers results with a cost of 27.9€ per kilogram weight-lost in continuous implementation. Key messages • The significant impact of obesity on premature mortality and healthcare systems calls for the systematic implementation of effective weight management programs that are available to patients for free. • It is possible to implement effective weight management program in Croatia without extra cost to patients for 27.9 € per kilogram weight-lost.

No Surprises Act independent dispute resolution outcomes for emergency services.

The No Surprises Act banned surprise billing and established a final-offer arbitration system, independent dispute resolution (IDR), to resolve disagreements between health plans and providers. One factor that arbiters must consider in the IDR process is the qualifying payment amount (QPA), the median contracted rate for the same or similar service in the same market as computed by health plans. We analyzed public IDR data from 2023 for the most common disputed professional service: evaluation and management of a moderate to severe emergency medicine visit. Providers won 86% of cases, with mean decisions 2.7 times the QPA. Private equity-backed providers won more often and higher monetary awards than other providers. The mean QPA was 2.4 times Medicare payments. Disputes were dominated by a small group of health plans and providers, so payments may not reflect the overall market for emergency services.

Comparison of Cardioprotective Potential of Cannabidiol and β-Adrenergic Stimulation against Hypoxia/Reoxygenation Injury in Rat Atria and Ventricular Papillary Muscles

Background: Hypoxia is one of the most significant pathogenic factors in cardiovascular diseases. Preclinical studies suggest that nonpsychoactive cannabidiol (CBD) and β-adrenoceptor stimulation might possess cardioprotective potential against ischemia-reperfusion injury. The current study evaluates the influence of hypoxia-reoxygenation (H/R) on the function of atria and ventricular papillary muscles in the presence of CBD and the nonselective β-adrenoceptor agonist isoprenaline (ISO). Methods: The concentration curves for ISO were constructed in the presence of CBD (1 µM) before or after H/R. In chronic experiments (CBD 10 mg/kg, 14 days), the left atria isolated from spontaneously hypertensive (SHR) and their normotensive control (WKY) rats were subjected to H/R following ISO administration. Results: Hypoxia decreased the rate and force of contractions in all compartments. The right atria were the most resistant to hypoxia regardless of prior β-adrenergic stimulation. Previous β-adrenergic stimulation improved recovery in isolated left atria and right (but not left) papillary muscles. Acute (but not chronic) CBD administration increased the effects of ISO in left atria and right (but not left) papillary muscles. Hypertension accelerates left atrial recovery during reoxygenation. Conclusion: H/R directly modifies the function of particular cardiac compartments in a manner dependent on cardiac region and β-adrenergic prestimulation. The moderate direct cardioprotective potential of CBD and β-adrenergic stimulation against H/R is dependent on the cardiac region, and it is less than in the whole heart with preserved coronary flow. In clinical terms, our research expands the existing knowledge about the impact of cannabidiol on cardiac ischemia, the world′s leading cause of death.

Wound healing activity of Ipomoea staphylina leaves extract in Wistar rats

Wound repair is the practice of repairing the skin and other soft tissues after an injury. An inflammatory response is activated after an injury, and cells below the dermis (deepest skin layer) begin to produce more collagen (connective tissue). A scientific assessment was made for the wound-healing potential of Ipomoea staphylina leaves extract, using ethanol. The crude extract was made into a 2.5% and 5% (w/w) ointment and tested for wound healing activity in Wistar rats using excision and incision wound models. In the excision wound model, the period of epithelialization was reduced and an increase in wound contraction rate was observed in the extract treated groups (III and IV). On the tenth day, tissue from the excision wound area was taken and processed for the assessment of pro-inflammatory cytokines (TNF-α), and it was found that there was a notable decrease in the TNF-α concentration in the extract-treated animals. In an incision wound model, the breaking strength was significantly increased in animals treated with 2.5% and 5% (w/w) ointment of I. staphylina leaves extract. The extract significantly promoted fibroblast migration in an in vitro experiment (scratch assay), which may have been caused by the presence of flavonoids.

Incidence and Outcomes of Pregnant Trauma Patients With Positive Urine Toxicology: A Southern California Multicenter Study.

Background: The use of illicit substances during pregnancy has increased 4-fold in the past two decades, negatively impacting both mother and fetus. The rate and clinical outcomes of substance use in pregnant trauma patients (PTPs) are not well studied. We sought to evaluate clinical outcomes of PTPs with positive urine toxicology, hypothesizing a higher rate of in-hospital maternal complications for PTPs with a positive urine toxicology ((+)Utox) compared to those testing negative ((-)Utox). Methods: PTPs (≥18years old) were included in this multicenter retrospective study between 2016 and 2021. We included patients with known urine toxicology results and compared (+)Utox vs (-)Utox PTPs. Results: From 852 PTPs, 84 (9.8%) had a (+)Utox with the most common illicit substance being THC (57%) followed by methamphetamine (44%). (+)Utox PTPs had higher rates of blunt head injury (9.5% vs 4.2%, P = .028), extremity injury (14.3% vs 6.5%, P = .009), domestic violence (21.4% vs 5.9%, P < .001), suicide attempt (3.6% vs 0.3%, P < .001), and uterine contractions (46% vs 23.5%, P < .001). Abnormal fetal heart tracing, premature rupture of membranes and placental injury were similar between groups (all P > .05). The rate of maternal complications was similar in both groups (all P > .05). Conclusion: In this study, the rate of (+)Utox in PTPs was 9.8%. The (+)Utox group had similar rates of maternal complications but more commonly experienced uterine contractions which may be related to the physiology of drugs such as methamphetamines. PTPs with (+)Utox also more commonly were victims of domestic violence and suicide attempt, which merits further prevention research efforts.

Comparative Analyses of Dynamic Transcriptome Profile of Heart Highlight the Key Response Genes for Heat Stress in Zhikong Scallop Chlamys farreri.

Heat stress resulting from global climate change has been demonstrated to adversely affect growth, development, and reproduction of marine organisms. The Zhikong scallop (Chlamys farreri), an important economical mollusk in China, faces increasing risks of summer mortality due to the prolonged heat waves. The heart, responsible for transporting gas and nutrients, is vital in maintaining homeostasis and physiological status in response to environmental changes. In this study, the effect of heat stress on the cardiac function of C. farreri was investigated during the continuous 30-day heat stress at 27 °C. The results showed the heart rate of scallops increased due to stress in the initial phase of high temperature exposure, peaking at 12 h, and then gradually recovered, indicating an acclimatization at the end of the experiment. In addition, the levels of catalase (CAT), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC) exhibited an initial increase followed by recovery in response to heat stress. Furthermore, transcriptome analysis of the heart identified 3541 differentially expressed genes (DEGs) in response to heat stress. Subsequent GO and KEGG enrichment analysis showed that these genes were primarily related to signal transduction and oxidative stress, such as the phosphatidylinositol signaling system, regulation of actin cytoskeleton, MAPK signaling pathway, FoxO signaling pathway, etc. In addition, two modules were identified as significant responsive modules according to the weighted gene co-expression network analysis (WGCNA). The upregulation of key enzymes within the base excision repair and gap junction pathways indicated that the heart of C. farreri under heat stress enhanced DNA repair and maintained cellular integrity. In addition, the variable expression of essential signaling molecules and cytoskeletal regulators suggested that the heart of C. farreri modulated cardiomyocyte contraction, intracellular signaling, and heart rate through complex regulation of phosphorylation and calcium dynamics in response to heat stress. Collectively, this study enhances our understanding of cardiac function and provides novel evidence for unraveling the mechanism underlying the thermal response in mollusks.

Nonparametric Bayesian estimation in a multidimensional diffusion model with high frequency data

AbstractWe consider nonparametric Bayesian inference in a multidimensional diffusion model with reflecting boundary conditions based on discrete high-frequency observations. We prove a general posterior contraction rate theorem in $$L^2$$ L 2 -loss, which is applied to Gaussian priors. The resulting posteriors, as well as their posterior means, are shown to converge to the ground truth at the minimax optimal rate over Hölder smoothness classes in any dimension. Of independent interest and as part of our proofs, we show that certain frequentist penalized least squares estimators are also minimax optimal.

The Roles of Moat Width and Outer Eyewall Contraction in Affecting the Timescale of Eyewall Replacement Cycle

AbstractThe timescale of eyewall replacement cycle (ERC) is critical for the prediction of intensity and structure changes of tropical cyclones (TCs) with concentric eyewall (CE) structures. Previous studies have indicated that the moat width can regulate the interaction between the inner and outer eyewalls and has a salient relationship with the ERC timescale. In this study, a series of sensitivity experiments are carried out to investigate the essential mechanisms resulting in the diversity of the duration of CEs using both simple and full‐physics models. Results reveal that a larger moat can induce stronger inflow under the same inner eyewall intensity by providing a longer distance for air parcels to accelerate in the boundary layer. Thus, there is greater inward absolute vorticity flux to sustain the inner eyewall. Besides, the equivalent potential temperature (θe) budget indicates that the vertical advection and surface flux of moist entropy can overbalance the negative contribution from the horizontal advection and lead to an increasing trend of θe in the inner eyewall. This suggests that the thermodynamic process in the boundary layer is not indispensable to the inner eyewall weakening. It is also found that the contraction rate of the secondary eyewall, which directly influences the moat width, is subject to the activity of outer spiral rainbands. By directly introducing positive wind tendency outside the eyewall and indirectly promoting a vertically tilted eyewall structure, active convection in the outer region will impede or even suspend the contraction of the outer eyewall and hence extend the ERC timescale.

A NOVEL WOUND DRESSING WITH SILKWORM COCOON SCAFFOLD TO FASTEN WOUND HEALING: AN IN VIVO STUDY USING RAT EXCISION WOUND MODEL

Objective: The study aimed to compare the effectiveness of silver-nano laden silkworm cocoon scaffold (SWCS), L-Ascorbic acid laden SWCS (AA-SWCS) over standard wet collagen sheet used for wound healing in rat incision wound model. Methods: A total of 24 Wistar rats (of either sex, pathogen free, 10–12 weeks old) were used in this study. SWCS was prepared and an excision wound model was carried out to study the wound healing capacity in four study groups. Dressings were made with silver nanoparticles SWCS (AgNP-SWCS), AA-SWCS and compared with wet collagen sheet regularly. Friedman’s test was used for analysis. Results: The results clearly indicate that both AgNP-SWCS and AA-SWCS significantly accelerate wound healing compared to the standard wet collagen sheet. The AgNP-SWCS outperformed the others in terms of wound contraction rate, histological quality of healing, and microbial load reduction. The AA-SWCS also showed enhanced healing properties, particularly in collagen synthesis and tissue organization. Conclusion: The study suggests that both AgNP-SWCS and AA-SWCS are highly effective alternatives to traditional collagen dressings for wound healing. These innovative scaffolds could represent a new frontier in wound care, providing enhanced healing rates, improved tissue quality, and reduced infection risks, ultimately leading to better patient outcomes.

Exendin-4 promotes ischemia-reperfusion flap survival by upregulating Gpx4 to inhibit ferroptosis

BackgroundEffective drugs for preventing or treating skin flap necrosis remain elusive. In this study, we investigated the potential protective effect of exendin-4 against skin flap ischemia-reperfusion injury (IRI) through the inhibition of ferroptosis. MethodA rat abdomen was constructed with an island skin flap, and the superficial vascular pedicle of the abdominal wall was closed using a vascular clamp, which was removed after 8 h. Before surgery, RSL3 and ferrostatin-1 solutions were intraperitoneally injected. After the surgery, subcutaneous injections of exendin-4 were administered daily. The number of inflammatory cells, mean vascular density, collagen fiber content, and apoptosis and ferroptosis indicators were quantified 24 h after reperfusion. Survival, contraction rate, and blood perfusion of the skin flap were evaluated on days 1, 3, 5, and 7 after reperfusion. ResultsThe flap survival rate was significantly higher in the exendin-4 group than that in the injury group, whereas the contraction rate was lower. Compared with the injury group, the exendin-4 group showed less inflammatory cell infiltration, higher vascular density, and less collagen fiber loss. At the molecular level, the exendin-4 group demonstrated opposite or elevated expression of apoptosis and ferroptosis indicators than those in the injury group, with significantly increased glutathione peroxidase 4 (Gpx4). Ferroptosis inhibitors and agonists enhanced and reversed the protective effects of exendin-4, respectively. ConclusionExendin-4 alleviates skin flap IRI by upregulating Gpx4 expression to inhibit ferroptosis. Therefore, exendin-4 may serve as a novel clinical treatment for skin flap IRI.

Motor unit firing rates during slow and fast contractions in boys and men.

Motor unit (MU) activation during maximal contractions is lower in children compared with adults. Among adults, discrete MU activation differs, depending on the rate of contraction. We investigated the effect of contraction rate on discrete MU activation in boys and men. Following a habituation session, 14 boys and 20 men completed two experimental sessions for knee extension and wrist flexion, in random order. Maximal voluntary isometric torque (MVIC) was determined before completing trapezoidal isometric contractions (70%MVIC) at low (10%MVIC/s) and high (35%MVIC/s) contraction rates. Surface electromyography was captured from the vastus lateralis (VL) and flexor carpi radialis (FCR) and decomposed into individual MU action potential (MUAP) trains. In both groups and muscles, the initial MU firing rate (MUFR) was greater (p < 0.05) at high compared with low contraction rates. The increase in initial MUFR at the fast contraction in the VL was greater in men than boys (p < 0.05). Mean MUFR was significantly lower during fast contractions only in the FCR (p < 0.05). In both groups and muscles, the rate of decay of MUFR with increasing MUAP amplitude was less steep (p < 0.05) during fast compared with slow contractions. In both groups and muscles, initial MUFRs, as well as MUFRs of large MUs were higher during fast compared with slow contractions. However, in the VL, the increase in initial MUFR was greater in men compared with boys. This suggests that in large muscles, men may rely more on increasing MUFR to generate torque at faster rates compared with boys.

PRP improves the outcomes of autologous skin graft transplantation on the esophagus by promoting angiogenesis and inhibiting fibrosis and inflammation.

Autologous skin graft (ASG) transplantation is a challenging approach but a promising option for patients to prevent postoperative esophageal stricture. Nonetheless, the current strategies require improvement. We aimed to investigate the effectiveness of the injection of platelet-rich plasma (PRP) before skin graft transplantation for extensive esophageal defects after endoscopic resection. Standardized complete circular endoscopic resection (5 cm in length) was performed in 27 pigs allocated into 3 groups. The artificial ulcers were treated with a fully covered esophageal stent (control group), ASG (ASG group), and submucosal injection of PRP with ASG (PRP-ASG group). Macroscopic evaluation and histological analysis of the remolded esophagus were performed 7, 14, and 28 days after surgery. The macroscopic evaluation indicated that submucosal injection of PRP before transplantation effectively promoted the survival rate of skin grafts and decreased the rate of mucosal contraction compared with those treated with ASG or stent alone. Histological analysis of submucosal tissue showed that this modified strategy significantly promoted wound healing of reconstructed tissues by enhancing angiogenesis, facilitating collagen deposition, and decreasing inflammation and fibrogenesis. These findings suggested that PRP might be used as a biological supplement to increase the esophageal skin graft survival rate and improve submucosal tissue remolding in a clinically relevant porcine model. With extremely low mucosal contraction, this novel combination strategy showed the potential to effectively prevent stenosis in extensive esophageal ulcers.

Human amniotic membrane hydrogel loaded with exosomes derived from human placental mesenchymal stem cells accelerate diabetic wound healing

Diabetic wound is one of the most common and costly complication in diabetic patients. Hence, numerous studies have been carried out to discover a suitable approach to enhance the process of wound healing. Biological hydrogels are commonly utilized for wound healing due to their suitable properties among different materials available. Herein we investigated whether human amniotic membrane hydrogel (hAMH) loaded with human placental mesenchymal stem cells (PlaMSCs)-derived exosomes could promote healing in diabetic rats. Sixty diabetic rats were randomly assigned into the control group, hAMH group, exosome group, and hAMH+Exosome group. According to the phases of wound healing, sampling was done on days 7, 14, and 21 for further assessments. Our findings showed a significant increase in wound contraction rate, new epidermal length, fibroblast and blood vessel count, collagen density, and the levels of antioxidative factors (GSH, SOD, and CAT) in the treatment groups compared to the control group, with more pronounced effects observed in the hAMH+Exosome group. Furthermore, the levels of bFGF and VEGF gene expression significantly increased in each treatment group when compared to the control group, with the highest levels observed in the hAMH+Exosome group. This occurred as the hAMH+Exosome group showed a greater decrease in neutrophil count, the expression of TNF-α and IL-1β genes, and the levels of an oxidative factor (MDA) compared to the other groups. In summary, the combination of hAMH and PlaMSCs-derived exosomes was determined to have a more significant effect on healing diabetic wounds.

Use of cardiac cell cultures from salmonids to measure the cardiotoxic effect of environmental pollutants.

Environmental stressors such as micro- and nanosized plastic particles (MNPs) or crude oil have a detrimental effect on aquatic animals; however, the impact upon the cardiovascular system of fish remains relatively under-researched. This study presents a novel approach for investigating the effect of crude oil and MNPs on the cardiac system of fish. We used salmonid larvae and cardiac cell cultures derived from hearts of salmonid fish and exposed them to environmental stressors. Following exposure to plastic particles or crude oil, the larvae exhibited some variation in contraction rate. In contrast, significant alterations in the contraction rate were observed in all cardiac cell cultures. The greatest differences between the control and treatment groups were observed in cardiac cell cultures derived from older brown trout. Following 7 days of exposure to MNPs or crude oil in Atlantic salmon larval hearts or cardiac cell cultures, there were only minor responses noted in mRNA expression of the selected marker genes. These findings show the use of a novel invitro technique contributing to the existing body of knowledge on the impact of MNPs and crude oil on the cardiovascular system of salmonids and the associated risk.

Rapamycin Treatment Reduces Brain Pericyte Constriction in Ischemic Stroke.

The contraction and subsequent death of brain pericytes may play a role in microvascular no-reflow following the reopening of an occluded artery during ischemic stroke. Mammalian target of rapamycin (mTOR) inhibition has been shown to reduce motility/contractility of various cancer cell lines and reduce neuronal cell death in stroke. However, the effects of mTOR inhibition on brain pericyte contraction and death during ischemia have not yet been investigated. Cultured pericytes exposed to simulated ischemia for 12 h in vitro contracted after less than 1 h, which was about 7 h prior to cell death. Rapamycin significantly reduced the rate of pericyte contraction during ischemia; however, it did not have a significant effect on pericyte viability at any time point. Rapamycin appeared to reduce pericyte contraction through a mechanism that is independent of changes in intracellular calcium. Using a mouse model of middle cerebral artery occlusion, we showed that rapamycin significantly increased the diameter of capillaries underneath pericytes and increased the number of open capillaries 30 min following recanalisation. Our findings suggest that rapamycin may be a useful adjuvant therapeutic to reduce pericyte contraction and improve cerebral reperfusion post-stroke.

L-Arginine-Loaded Oxidized Isabgol/Chitosan-Based Biomimetic Composite Scaffold Accelerates Collagen Synthesis, Vascularization, and Re-epithelialization during Wound Healing in Diabetic Rats.

Impaired wound healing in diabetic wounds is common due to infection, inflammation, less collagen synthesis, and vascularization. Diabetic wound healing in patients is still a challenge and needs an ideal wound dressing to treat and manage diabetic wounds. Herein, an efficacious wound dressing biomaterial was fabricated by cross-linking oxidized isabgol (Oisab) and chitosan (Cs) via trisodium trimetaphosphate and Schiff base bonds. l-Arginine (l-Arg) was incorporated as a bioactive substance in the Oisab + Cs scaffold to promote cell adhesion, cell proliferation, collagen synthesis, and vascularization. The fabricated scaffolds showed microporous networks in the scanning electron microscopy analysis. The scaffold also possessed excellent hemocompatibility. In vitro studies using fibroblasts (L929 and human dermal fibroblast cells) confirmed the cytocompatibility of these scaffolds. The results of the in vivo chicken chorioallantoic membrane assay confirmed the proangiogenic activity of the Oisab + Cs + l-Arg scaffolds. The wound-healing potential of these scaffolds was studied in streptozotocin-induced diabetic rats. This in vivo study showed that the period of epithelialization in the Oisab + Cs + l-Arg scaffold-treated wounds was 21.67 ± 1.6 days, which was significantly faster than the control (30.33 ± 2.5 days). Histological and immunohistochemical studies showed that the Oisab + Cs + l-Arg scaffolds significantly accelerated the rate of wound contraction by reducing inflammation, improving collagen synthesis, and promoting neovascularization. These findings suggest that the Oisab + Cs + l-Arg scaffolds could be beneficial in treating diabetic wounds in clinical applications.