Study on the Wettability and Methane Desorption Characteristics of Coal under High Pressure with Different Surfactants.

In the process of coalbed methane extraction, due to the strong hydrophilicity of coal, the surface interaction force between water and the coal matrix is strong. The hydrophobic effect of the coal seam during drainage and pressure reduction is not significant, and adsorbed methane is difficult to desorb. In order to reduce the surface interaction force promoting methane desorption between water and coal, the surfactants NH766, G526, and D001 with a concentration of 0.1% were selected. A pressure of 12 MPa, which is close to that used for the on-site mining of coalbed methane in Baode, was selected as the experimental condition to simulate hydraulic fracturing of high fat coal, and the influence of different surfactants on methane desorption characteristics was analyzed. Combining contact angle experiments and infrared spectroscopy experiments, we explored the changes in wettability of the coal samples. We compared the changes in wettability and methane desorption characteristics and explored the similarities between these changes. The experimental results showed that after NH766 treatment, the content of oxygen-containing functional groups in coal rock decreased by 30%, and the contact angle of the coal matrix surface increased by 10°. Furthermore, its hydrophobicity was enhanced, and the desorption amount increased by 24%. In contrast, the oxygen-containing functional groups in coal rock after G526 and D001 treatments increased by 5% and 16%, respectively, and the contact angle of the coal matrix surface became smaller. Furthermore, its hydrophilicity was enhanced, and the desorption amount was reduced by 12.5% and 20%, respectively. NH766 reduces wettability and promotes methane desorption, and it can be applied to improve CBM extraction efficiency. G526 and D001 enhance wettability and inhibit methane desorption, which make them suitable for dust prevention and gas control in coal mines.

[Extracorporeal Membrane Oxygenation Combined With Interventional Thrombectomy for Treating High-Risk Pulmonary Embolism Caused by Protein C Deficiency:Report of One Case].

Hereditary protein C deficiency is a chromosomal genetic disease caused by mutations in the protein C gene,which can lead to venous thrombosis and is mostly related to mutations in exons 4-9 and intron 8.Fatal pulmonary embolism caused by mutations in the protein C gene is rare,and the treatment faces great challenges.This article reports a case of fatal pulmonary embolism caused by a frameshift mutation in exon 8 of the protein C gene and summarizes the treatment experience of combining extracorporeal membrane oxygenation (for respiratory and circulatory support) with interventional thrombectomy,providing a basis for the diagnosis and treatment of this disease.

Effects of an early intensive blood pressure-lowering strategy using remifentanil and dexmedetomidine in patients with spontaneous intracerebral hemorrhage: a multicenter, prospective, superiority, randomized controlled trial.

BACKGROUND: Although it has been established that elevated blood pressure and its variability worsen outcomes in spontaneous intracerebral hemorrhage, antihypertensives use during the acute phase still lacks robust evidence. A blood pressure-lowering regimen using remifentanil and dexmedetomidine might be a reasonable therapeutic option given their analgesic and anti-sympathetic effects. The objective of this superiority trial was to validate the efficacy and safety of this blood pressure-lowering strategy that uses remifentanil and dexmedetomidine in patients with acute intracerebral hemorrhage. METHODS: In this multicenter, prospective, single-blinded, superiority randomized controlled trial, patients with intracerebral hemorrhage and systolic blood pressure (SBP) ≥150 mmHg were randomly allocated to the intervention group (a preset protocol with a standard guideline management using remifentanil and dexmedetomidine) or the control group (standard guideline-based management) to receive blood pressure-lowering treatment. The primary outcome was the SBP control rate (<140 mmHg) at 1 h posttreatment initiation. Secondary outcomes included blood pressure variability, neurologic function and clinical outcomes. RESULTS: A total of 338 patients were allocated to the intervention (n = 167) or control group (n = 171). The SBP control rate at 1 h posttreatment initiation in the intervention group was higher than that in controls (101/161, 62.7% vs. 66/166, 39.8%, difference 23.2%, 95% CI, 12.4 to 34.1%, P < 0.001). Analysis of secondary outcomes indicated that patients in the intervention group could effectively reduce agitation while achieving lighter sedation, but no improvement in clinical outcomes was observed. Regarding safety, the incidence of bradycardia and respiratory depression was higher in the intervention group. CONCLUSIONS: Among intracerebral hemorrhage patients with a SBP ≥ 150 mmHg, a preset protocol using a remifentanil and dexmedetomidine-based standard guideline management significantly increased the SBP control rate at 1 h posttreatment compared with the standard guideline-based management. (ClinicalTrials.gov number: NCT03207100, Registration date: June 30, 2017).

Notoginsenoside R1 improves intestinal microvascular functioning in sepsis by targeting Drp1-mediated mitochondrial quality imbalance.

CONTEXT: Sepsis can result in critical organ failure, and notoginsenoside R1 (NGR1) offers mitochondrial protection. OBJECTIVE: To determine whether NGR1 improves organ function and prognosis after sepsis by protecting mitochondrial quality. MATERIALS AND METHODS: A sepsis model was established in C57BL/6 mice using cecum ligation puncture (CLP) and an in vitro model with lipopolysaccharide (LPS, 10 µg/mL)-stimulated primary intestinal microvascular endothelial cells (IMVECs) and then determine NGR1's safe dosage. Groups for each model were: in vivo-a control group, a CLP-induced sepsis group, and a CLP + NGR1 treatment group (30 mg/kg/d for 3 d); in vitro-a control group, a LPS-induced sepsis group, and a LPS + NGR1 treatment group (4 µM for 30 min). NGR1's effects on survival, intestinal function, mitochondrial quality, and mitochondrial dynamic-related protein (Drp1) were evaluated. RESULTS: Sepsis resulted in approximately 60% mortality within 7 days post-CLP, with significant reductions in intestinal microvascular perfusion and increases in vascular leakage. Severe mitochondrial quality imbalance was observed in IMVECs. NGR1 (IC50 is 854.1 µM at 30 min) targeted Drp1, inhibiting mitochondrial translocation, preventing mitochondrial fragmentation and restoring IMVEC morphology and function, thus protecting against intestinal barrier dysfunction, vascular permeability, microcirculatory flow, and improving sepsis prognosis. DISCUSSION AND CONCLUSIONS: Drp1-mediated mitochondrial quality imbalance is a potential therapeutic target for sepsis. Small molecule natural drugs like NGR1 targeting Drp1 may offer new directions for organ protection following sepsis. Future research should focus on clinical trials to evaluate NGR1's efficacy across various patient populations, potentially leading to novel treatments for sepsis.

Safety and efficacy of non-reduced use of caspofungin in patients with Child-Pugh B or C cirrhosis: a real-world study.

BACKGROUND AND PURPOSE: The need for dose adjustment of caspofungin in patients with hepatic impairment is controversial, especially for those with Child-Pugh B or C cirrhosis. The purpose of this study was to investigate the safety and efficacy of standard-dose caspofungin administration in Child-Pugh B and C cirrhotic patients in a real-world clinical setting. PATIENTS AND METHODS: The electronic medical records of 258 cirrhotic patients, including 67 Child-Pugh B patients and 191 Child-Pugh C patients, who were treated with standard-dose of caspofungin at the Second Affiliated Hospital of Chongqing Medical University, China, from March 2018 to June 2023 were reviewed retrospectively. The white blood cells (WBC), hepatic, renal and coagulation function results before administration and post administration on days 7, 14 and 21 were collected, and the efficacy was assessed in all patients at the end of caspofungin therapy. RESULTS: Favorable responses were achieved in 137 (53.1%) patients while 34 (13.2%) patients died. We observed that some patients experienced an increase of prothrombin time (PT) or international normalized ratio (INR), or a decrease of WBC, but no exacerbation of hepatic or renal dysfunction were identified and no patient required dose interruption or adjustment because of an adverse drug reaction during treatment with caspofungin. CONCLUSIONS: Standard-dose of caspofungin can be safely and effectively used in patients with Child-Pugh B or C cirrhosis, and we appealed to re-assess the most suitable dosing regimen in this population to avoid a potential subtherapeutic exposure.

Simulation Study of N2-Hydraulic Compound Fracturing Based on the Volumetric Opening Model.

N2-hydraulic compound fracturing (NHCF) is an innovative technology aimed at addressing coalbed methane development challenges in low-permeability, low-pressure coal reservoirs in China. However, limited research has been focused on the evolution of damage zones, pore pressure fields, and fluid pressure characteristics in this context. In this paper, we establish a finite element seepage equation based on the volumetric opening model and construct a finite element model for horizontal well stage fracturing. We used the physical and mechanical parameters specific to coal reservoirs in the Xinjing coal mine. Subsequently, we conducted numerical simulations of N2 fracturing (NF), hydraulic fracturing (HF), and NHCF using ANSYS. The results indicate that the initiation-fracturing pressure of NHCF is lower than that of HF but higher than NF, but the steady-fracturing pressure is higher than HF and NF. Moreover, numerical simulation shows that under the same water injection volume, the total volumetric opening formed by NHCF is about 2 times that of HF, NF is the smallest, and the damage zone and pore pressure field caused by NHCF are the largest. Finally, when comparing the casing pressure curve of NHCF by field test with the fluid pressure curve of wellbore obtained from numerical simulation, we observe a strong correlation; the steady fracturing pressure of NF is about 13 MPa, which is basically consistent with the numerical simulation, and the steady- fracturing pressure of HF after NF is about 27 MPa, which is slightly lower than the 30 MPa in numerical simulation. This is because in the numerical simulation, the reservoir parameters after NF can be inherited to the subsequent HF, which cannot be done in the field test. This study presents a novel method for numerical fluid fracturing simulation, offering a fresh perspective on the subject.

Pheochromocytoma crisis with refractory Acute Respiratory Distress Syndrome (ARDS), Takotsubo syndrome, emergency adrenalectomy, and need for Extracorporeal Membrane Oxygenation (ECMO) in a previously undiagnosed and asymptomatic patient, due to the use of metoclopramide.

BACKGROUND: Pheochromocytoma (PCC) crisis is a rare life-threatening endocrine emergency. The diagnosis and treatment of PCC crisis, with acute respiratory distress syndrome (ARDS) as the first manifestation, is highly challenging, and traditional PCC management strategies are no longer suitable for these patients. CASE PRESENTATION: A 46-year-old female patient was admitted to the Intensive Care Unit (ICU) following sudden-onset acute respiratory distress and subsequent initiation of mechanical ventilation via endotracheal intubation. She was initially suspected of having a PCC crisis through the bedside critical care ultrasonic examination protocol. The computed tomography examination revealed a left adrenal neoplasm of 6.5cm × 5.9cm. The plasma-free metanephrine level was 100 times higher than the reference value. These findings were compatible with her PCC diagnosis. Alpha-blockers and fluid intake were started immediately. The endotracheal intubation was removed on the 11th day after admission to the ICU. The patient progressed to severe ARDS again, and invasive ventilation and continuous renal replacement therapy were needed. Despite aggressive therapy, her condition deteriorated. Therefore, she underwent veno-arterial extracorporeal membrane oxygenation (VA-ECMO)-assisted emergency adrenalectomy after multidisciplinary discussion. Postoperatively, the patient was supported by VA-ECMO for 7days. She was discharged from the hospital on day 30 after tumor resection. CONCLUSIONS: This case highlighted the challenges in diagnosing and managing ARDS associated with PCC crisis. The traditional preoperative preparation protocol and optimal operation timing for patients with PCC are not suitable for patients with PCC crisis. Patients with life-threatening PCC crisis may benefit from early tumor removal, and VA-ECMO could maintain hemodynamic stability during and after surgery.

Mechanism and Practice of Multifracturing Using Dynamic Loads in a Low-Permeability Coal Reservoir.

The geological conditions of coal reservoirs in China are complex, and the reservoir permeability is generally lower. Multifracturing is an effective method of improving reservoir permeability and coalbed methane (CBM) production. In this study, two types of dynamic loads, CO2 blasting and a pulse fracturing gun (PF-GUN), were used to conduct multifracturing engineering tests in nine surface CBM wells in the Lu'an mining area in the central and eastern parts of the Qinshui Basin. The curves of pressure versus time of the two dynamic loads were obtained in the laboratory. The prepeak pressurization time of the PF-GUN was 200 ms, and that of the CO2 blasting was 2.05 ms, which just falls in the optimum pressurization time of multifracturing. The microseismic monitoring results revealed that, in terms of the fracture morphology, both the CO2 blasting and PF-GUN loads produced multiple sets of fractures in the near-well zone. In the six wells used for the CO2 blasting tests, an average of three branch fractures were produced outside of the main fracture, and the average angle between the main fracture and the branch fractures exceeded 60°. In the three wells stimulated by PF-GUN, an average of two branch fractures were produced outside of the main fracture, and the average angle between the main fracture and the branch fractures was 25-35°. The multifracture characteristics of the fractures formed via CO2 blasting were more obvious. However, a coal seam is a multifracture reservoir with a large filtration coefficient; the fracture will not extend after reaching the maximum scale under a certain gas displacement condition. Compared with the traditional hydraulic fracturing technique, the nine wells used in the multifracturing tests exhibited an obvious stimulation effect with an average increase of 51.4% in daily production. The results of this study provide an important technical reference for the efficient development of CBM in low- and ultralow-permeability reservoirs.

Poromechanical Modeling and Numerical Simulation of Hydraulic Fracture Propagation.

Hydraulic fracturing (HF) is an important technique for enhancing the permeability of petroleum and gas reservoirs. To understand the coupling response mechanism of fluid pressure and in situ stress during the expansion of hydraulic fractures-based on the theory of the fluid flow of seepage porous media and damage mechanics-a poromechanical model of hydraulic fracture propagation is proposed and the finite element method (FEM) numerical weak coupling calculation method of hydraulic fracturing is realized. First, the effect of the coupling stress field is described by introducing the ß value of the amount of pore volume that varies, resulting from internal pressure per unit of fluid internal, and the coupling calculation method of the pore pressure-effective stress-element damage-pore pressure expansion coefficient is formulated. Second, based on the concept of damage localization, a calculation method for the hydraulic fracture opening equation is proposed, and then the element damage-hydraulic fracture opening-permeability tensor-pore pressure field calculation cycle is established. The model indicates four stages of fracture propagation: I, fracture nucleation, II, kinetic propagation, III, steady propagation, and IV, propagation termination. Finally, as an example, a numerical simulation of three-dimension hydraulic fracturing is performed. In comparison to previous research, the morphology of the fracture zone and the fluid pressure contour of the horizontal section are approximately ellipses, which verify the feasibility of the weak coupling calculation method; the fracture parameters verify its accuracy, which include the length, width, and fluid pressure.

Coal Structure Characteristics in the Northern Qinshui Basin and Their Discrimination Method Based on the Particle Size of Drilling Cuttings.

Coal structure, including primary coal, cataclastic coal, granulated coal, and mylonitized coal, is one of the key factors controlling coal and gas outburst, and it also determines the efficiency of coalbed methane (CBM) extraction. Therefore, it is significant to identify the characteristics of coal structures and to predict them in advance. In this work, the spatial distribution, mechanical properties, and microscopic morphology of the four coal structures from the No. 3 coal seam of the Xinyuan Mine in the northern part of the Qinshui Basin were investigated through the in situ observation in the roadway, the hardness coefficient (f) test, and the scanning electron microscope analysis. Moreover, the drilling cuttings from the gas pressure releasing holes were sampled and sieved, and then, the correspondence between different coal structures and the particle size of the cuttings was analyzed quantitatively based on the Rosin-Rammler model. The result shows that the spatial distribution of the coal structure has strong heterogeneity in the vertical and lateral directions. The f value decreases successively with the increase in coal structure deformation, which indicate that f can directly characterize the coal structure. Furthermore, the relations between f and drilling cutting average particle size (d 0), crushability indicator (n), crushing degree index (λ), and the median diameter (d 50) were established. Specifically, the coal deformation degree is positively correlated with the mass fraction of large particles in the cuttings under the same drilling parameters. Overall, as f increases, d 0 and d 50 decrease, and n and λ increase. However, parameters d 0, d 50, and λ of granulated coal are inconsistent with other coal structures, and mylonitized coal is inconsistent with other coal structures in n, as a result of the coal structure broken characteristics itself and the difference in the stress state between the coal and the drill bit during the rock breaking process. Ultimately, the coal structures determined by the surface CBM well logging curve and the cuttings particle size method were compared, and they have a high degree of coincidence in the distinction between primary coal and tectonic coal.

Geological Controls on the Gas Content and Permeability of Coal Reservoirs in the Daning Block, Southern Qinshui Basin.

The gas content and permeability of the coal reservoir are the key factors affecting coalbed methane (CBM) productivity. To investigate the geological controls on the permeability and gas content of coal reservoirs in the Daning block, southern Qinshui Basin, geological surveys combined with laboratory experiments, including coal petrology analysis, proximate analysis, and methane isothermal adsorption experiments, were carried out. The results show that the gas content of coals in the Daning block ranges from 5.56 to 17.57 (avg. 12.83) m3/t, and the coal permeability is generally above 0.1 mD, averaging 0.96 mD. The gas content of coal reservoirs shows decreasing trends with the increase in ash yield and moisture content, while tends to increase with the increase of vitrinite content; however, the correlation coefficients are all extremely low. The gas content presents a strong positive correlation with the burial depth of coal seams, but overall poorly correlates with the coal thickness. The CBM-rich areas are generally located at the hinge zones of secondary synclines, while the lower gas content areas commonly occur at the hinge zones of secondary anticlines. The normal faults are developed in the Daning block, and as expected, the gas content of coal seams that are near the normal faults is commonly lower. It was found that the well testing permeability of coal reservoirs in the Daning block decreases exponentially with the increase of the minimum horizontal stress (σh) and the maximum horizontal principal stress (σH). With the increase of the burial depth, the coal permeability also decreases exponentially. The primary and cataclastic structure coals generally have a higher hydro-fracturing permeability than the granulitic and mylonitic structure coals. This work can serve as a guide for the target area selections of CBM enrichment and high production in the Daning block.

Hepatoprotective Effect of Mitochondria-Targeted Antioxidant Mito-TEMPO against Lipopolysaccharide-Induced Liver Injury in Mouse.

The liver is vulnerable to sepsis, and sepsis-induced liver injury is closely associated with poor survival of sepsis patients. Studies have found that the overproduction of reactive oxygen species (ROS) is the major cause of oxidative stress, which is the main pathogenic factor for the progression of septic liver injury. The mitochondria are a major source of ROS. Mito-TEMPO is a mitochondria-specific superoxide scavenger. The aim of this study was to investigate the effect of Mito-TEMPO on lipopolysaccharide- (LPS-) induced sepsis mice. We found that Mito-TEMPO pretreatment inhibited inflammation, attenuated LPS-induced liver injury, and enhanced the antioxidative capability in septic mice, as evidenced by the decreased MDA content and the increased SOD activity. In addition, Mito-TEMPO restored mitochondrial size and improved mitochondrial function. Finally, we found that the levels of pyroptosis-related proteins in the liver of LPS-treated mice were lower after pretreatment with Mito-TEMPO. The mechanisms could be related to Mito-TEMPO enhanced antioxidative capability and improved mitochondrial function, which reflects the ability to neutralize ROS.

In Situ Stress Distribution and Variation Monitored by Microseismic Tracking on a Fractured Horizontal Well: A Case Study from the Qinshui Basin.

In situ stress is an important parameter regulating the production of coalbed methane (CBM), and the monitoring of rock deformation can provide a description of the state of stress. Microseismic monitoring in a multistage fractured horizontal CBM well was conducted as a case study with a completion depth of 1445.36 m. The results show that there is a good correlation among the seismicity parameters, b-value, stress drop, fracture length, fracture density, and orientation. In the stress concentration region, the fracture is longer with a smaller density, where the b-value is lower. On the contrary, in the stress relaxation zone, the fracture is shorter with a complex shape, where the b-value is higher. Stress drop is relatively higher where fractures are concentrated, which indicate the areas with successful reservoir stimulation. The reliability of the above results was verified by the normal fault occurring between stages 7 and 8. In the area affected by the hanging wall of the normal fault (stage 6 and 7), the b-value is 0.38-0.39, while in the area affected by the footwall (stage 8 and 9), the b-value is 0.64-0.66. This phenomenon reflects an obvious stress concentration in the hanging wall of normal fault, which is consistent with the conventional understanding. The microseismic source parameters have great potential in evaluating reservoir stress. With further exploration of source parameters, microseismic will provide more support for CBM development.

Experimental Studies on the Enhancement of Permeability of Anthracite by Acidizing: A Case Study in the Daning Block, Southern Qinshui Basin.

As the most active and top producing area of coalbed methane (CBM) in China, the southern Qinshui Basin (SQB) is dominated by anthracite. Due to the low permeability of coals, plenty of non-gas-producing and low production CBM wells exist in the SQB. The permeability enhancement through some technological means is the key to increasing the CBM production of this area. In this paper, some typical anthracites were selected from the Daning block of the SQB to assess the effect of acidification treatments on permeability enhancement. The maceral composition determination shows that approximately 15% of minerals exist in the collected coal samples, and the X-ray diffractometer (XRD) results reveal that the minerals consist primarily of clay minerals, along with a little amount of quartz, calcite, and dolomite. Two types of acidizing fluids were used to conduct acidification treatments on the anthracites for different lengths of time. The N2 permeability of the anthracites before and after acidification was measured and compared. The results show that the original samples exhibit low permeability. As the acidification time increases, the permeability of all of the samples shows an increasing trend, and the acid sensitivity index I a increases rapidly first and then levels off, and finally approaches 1. After 48 h of acidification, the samples show an increase ranging from 8.75 to 22.67 times (avg. 14.3 times) the original permeability. The permeability enhancement of the SQB anthracites is mainly attributed to the dissolution of acid-soluble minerals in the cleat system of coal. The minerals in the cleats are completely or partially dissolved by the acids, generating some soluble and insoluble substances; when the fluid flows through, the cleat space is reallocated. Overall, the cleat demineralization by acids frees up a lot of cleat spaces, leading to an increase in cleat connectivity. As a result, the fluid movement becomes smooth and the permeability of coal improves.

Morphological characteristics associated with rupture risk of multiple intracranial aneurysms.

OBJECTIVE: To identify the morphological parameters that are related to intracranial aneurysms (IAs) rupture using a case-control model. METHODS: A total of 107 patients with multiple IAs and aneurysmal subarachnoid hemorrhage between August 2011 and February 2017 were enrolled in this study. Characteristics of IAs location, shape, neck width, perpendicular height, depth, maximum size, flow angle, parent vessel diameter (PVD), aspect ratio (AR) and size ratio (SR) were evaluated using CT angiography. Multiple logistic regression analysis was used to identify the independent risk factors associated with IAs rupture. Receiver operating characteristic curve analysis was performed on the final model, and the optimal thresholds were obtained. RESULTS: IAs located in the internal carotid artery (ICA) was associated with a negative risk of rupture, whereas AR, SR1 (height/PVD) and SR2 (depth/PVD) were associated with increased risk of rupture. When SR was calculated differently, the odds ratio values of these factors were also different. The receiver operating characteristic curve showed that AR, SR1 and SR2 had cut-off values of 1.01, 1.48 and 1.40, respectively. SR3 (maximum size/PVD) was not associated with IAs rupture. CONCLUSIONS: IAs located in the ICA are associated with a negative risk of rupture, while high AR (>1.01), SR1 (>1.48) or SR2 (>1.40) are risk factors for multiple IAs rupture.

The analysis on risk factors and clinical treatment of craniocerebral injury concurrent with acute kidney injury.

The main objective of this study was to investigate the risk factors and clinical treatment of craniocerebral injury concurrent with acute kidney injury. A total of 220 patients who suffered from craniocerebral injury from March 2010 to March 2012 in our Hospital were prospectively analyzed. Craniocerebral injury was defined according to the medical history, the verification of CT, and some investigated scores. The acute kidney injury was defined as a relative 47% increase of serum creatinine. The method of multivariate logistic regression analysis was used to evaluate the possible risk factors associated with post-craniocerebral injury concurrent with acute kidney injury. The clinical treatments of craniocerebral injury concurrent with acute kidney injury were also identified via experimental results, and the pathological mechanism of craniocerebral injury concurrent with acute kidney injury was found to be related to cerebral tissue lesions, but some potential factors were ambiguous. The incidence of acute kidney injury was 70.2% with craniocerebral injury. In hospital, mortality of acute kidney injury patients was 31.2%, which was 6.019 times of non-acute kidney injury patients (p < 0.01). The incidence of acute kidney injury in patients with craniocerebral injury was 58.3%, which was significantly higher compared to moderate and mild groups (p < 0.01). Unconditional multivariate logistic regression analysis results revealed that lower score, elderly, and male were the independent predictors of acute kidney injury episodes. Finally, some important factors were worthy of detailed study and further investigation.

7,8-dihydroxyflavone, a small-molecule tropomyosin-related kinase B (TrkB) agonist, attenuates cerebral ischemia and reperfusion injury in rats.

7,8-dihydroxyflavone (7,8-DHF) is a recently identified potent agonist of tropomyosin-related kinase B that can cross the blood-brain barrier after oral or intraperitoneal administration. The aim of the present study was to determine whether 7,8-DHF has neuroprotective effects against cerebral ischemia and reperfusion (I/R) injury and, if so, to investigate the possible underlying mechanisms. Cerebral I/R injury rats were induced by middle cerebral artery occlusion for 90 min followed by reperfusion for 24 h. 7,8-DHF was administered intraperitoneally at a dose of 5 mg/kg immediately after ischemia. Our results showed that 7,8-DHF significantly reduced neurological deficit scores, infarct volumes, and neuronal apoptosis in brains of I/R rats. Meanwhile, 7,8-DHF also increased Bcl-2 expression, decreased expression of cleaved caspase-3, Bax and inducible nitric oxide synthase, and inhibited nuclear factor-κB activation in ischemic cortex. Finally, malondialdehyde and nitric oxide contents were reduced, but activities of glutathione, glutathione peroxidase and superoxide dismutase were restored in ischemic cortex treated with 7,8-DHF. Taken together, our findings demonstrated that 7,8-DHF is able to protect against cerebral I/R injury, which may be, at least in part, attributable to its anti-apoptotic, anti-oxidative and anti-inflammatory actions.

Establishment of a blunt impact-induced brain injury model in rabbits.

OBJECTIVE: To establish an animal model to replicate the blunt impact brain injury in forensic medicine. METHODS: Twenty-four New Zealand white rabbits were randomly divided into control group (n equal to 4), minor injury group (n equal to 10) and severe injury group (n equal to 10). Based on the BIM-II Horizontal Bio-impact Machine, self-designed iron bar was used to produce blunt brain injury. Two rabbits from each injury group were randomly selected to monitor the change of intracranial pressure (ICP) during the impacting process by pressure microsensors. Six hours after injury, all the rabbits were dissected to observe the injury morphology and underwent routine pathological examination. RESULTS: Varying degrees of nervous system positive signs were observed in all the injured rabbits. Within 6 hours, the mortality rate was 1/10 in the minor injury group and 6/10 in the severe injury group. Morphological changes consisted of different levels of scalp hematoma, skull fracture, epidural hematoma, subdural hematoma, subarachnoid hemo- rrhage and brain injury. At the moment of hitting, the ICP was greater in severe injury group than in mild injury group; and within the same group, the impact side showed positive pressure while the opposite side showed negative pressure. CONCLUSIONS: Under the rigidly-controlled experimental condition, this animal model has a good reproducibility and stable results. Meanwhile, it is able to simulate the morphology of iron strike-induced injury, thus can be used to study the mechanism of blunt head injury in forensic medicine.