Electrohydrodynamic Direct-Writing Micro/Nanofibrous Architectures: Principle, Materials, and Biomedical Applications.

Electrohydrodynamic (EHD) direct-writing has recently gained attention as a highly promising additive manufacturing strategy for fabricating intricate micro/nanoscale architectures. This technique is particularly well-suited for mimicking the extracellular matrix (ECM) present in biological tissue, which serves a vital function in facilitating cell colonization, migration, and growth. The integration of EHD direct-writing with other techniques has been employed to enhance the biological performance of scaffolds, and significant advancements have been made in the development of tailored scaffold architectures and constituents to meet the specific requirements of various biomedical applications. Here we offer a comprehensive overview of EHD direct-writing, including its underlying principles, demonstrated materials systems, and biomedical applications. A brief chronology of EHD direct-writing is provided, along with an examination of the observed phenomena that occur during the printing process. The impact of biomaterial selection and architectural topographic cues on biological performance is also highlighted. Finally, the major limitations associated with EHD direct-writing are discussed. This article is protected by copyright. All rights reserved.

Diffuse Large B-Cell Lymphoma With Cardiac Invasion Presented as Acute Myocardial Infarction and Left Ventricular Hypertrophy: A Case Report.

Primary cardiac lymphoma is an exceedingly rare malignant tumor, with diffuse large B-cell lymphoma (DLBCL) being the most prevalent histological subtype. This disease has non-specific clinical manifestations, making early diagnosis crucial. However, DLBCL diagnosis is commonly delayed, and its prognosis is typically poor. Herein, we report the case of a 51-year-old male patient with DLBCL who presented with recurrent chest tightness for 4 months as the primary clinical symptom. The patient was admitted to the hospital and diagnosed with acute myocardial infarction and left ventricular hypertrophy with heart failure. Echocardiography revealed a progression from left ventricular thickening to local pericardial thickening and adhesion in the inferior and lateral walls of the left ventricle. Finally, pathological analysis of myocardial biopsy confirmed the diagnosis of DLBCL. After treatment with the R-CHOP chemotherapy regimen, the patient's chest tightness improved, and he was discharged. After 2 months, the patient succumbed to death owing to sudden ventricular tachycardia, ventricular fibrillation, and decreased blood pressure despite rescue efforts. Transthoracic echocardiography is inevitable for the early diagnosis of DLBCL, as it can narrow the differential and guide further investigations and interventions, thereby improving the survival of these patients.

Complexation-Induced Resolution Enhancement Pleiotropic Small Diameter Vascular Constructs with Superior Antibacterial and Angiogenesis Properties.

3D printing has been widely applied for preparing artificial blood vessels, which will bring innovation to cardiovascular disorder intervention. However, the printing resolution and anti-infection properties of small-diameter vessels (Φ < 6 mm) have been challenging in 3D printing. The primary objective of this research is to design a novel coaxial 3D-printing postprocessing method for preparing small-size blood vessels with improved antibacterial and angiogenesis properties. The coaxial printing resolution can be more conveniently improved. Negatively charged polyvinyl alcohol (PVA) and alginate (Alg) interpenetrating networks artificial vessels are immersed in positively charged chitosan (CTS) solution. Rapid dimensional shrinkage takes place on its outer surface through electrostatic interactions. The maximum shrinkage size of wall thickness can reach 61.2%. The vessels demonstrate strong antibacterial properties against Escherichia coli (98.8 ± 0.5%) and Staphylococcus aureus (97.6 ± 1.4%). In rat dorsal skin grafting experiments, Cu2+ can promote angiogenesis by regulating hypoxia-inducible factor-1 pathway. No artificial blood vessel blockage occurs after 5 days of blood circulation in vitro.

Chemical Characteristics and Cytotoxicity to GC-2spd(ts) Cells of PM2.5 in Nanjing Jiangbei New Area from 2015 to 2019.

PM2.5 is an air pollutant with complex components. After entering the body through respiration, PM2.5 can not only cause respiratory diseases, but also break through the blood-testis barrier and influence the reproductive system. PM2.5 with different components may result in different toxic effects. In the first five years of Nanjing Jiangbei New Area, industrial transformation would change the concentration and chemical fraction of PM2.5 in the local environment to a certain extent. In this study, PM2.5 collected in Nanjing Jiangbei New Area every autumn and winter from 2015 to 2019 was analyzed. PM2.5 concentration generally decreased year by year. The large proportion of secondary inorganic ions indicated the presence of secondary pollution at the sampling site. PM2.5 was mainly emitted from fossil fuel combustion and vehicle exhaust. The cytotoxicity of PM2.5 samples was evaluated by PM2.5 exposure to mouse spermatocytes (GC-2spd(ts) cells). Cell viability was relatively low in 2016 and 2018, and relatively high in 2017 and 2019. Reactive oxygen species levels and DNA damage levels followed similar trends, with an overall annual decrease. The cytotoxicity of PM2.5 on GC-2spd(ts) cells was significantly correlated with water-soluble ions, water-soluble organic carbon, heavy metals and polycyclic aromatic hydrocarbons (p < 0.01). According to principal component analysis and multiple linear regression, fossil fuel combustion, secondary transformation of pollutants and construction dust were identified as the major contributors to cytotoxic effects, contributing more than 50%.

Successful percutaneous coronary intervention with extracorporeal membrane oxygenation in a patient with acute inferior wall myocardial infarction complicated by electrical storm, cardiogenic shock, and cardiac arrest: a case report.

BACKGROUND: High-risk patients with coronary heart disease who develop acute myocardial infarction (AMI) have severe coronary lesions. If severe complications occur, such as malignant ventricular arrhythmia, cardiogenic shock, and cardiac arrest, implementation of emergency percutaneous coronary intervention (PCI) may be hindered, leading to a higher perioperative mortality rate. Extracorporeal membrane oxygenation (ECMO) can pave the way for rapid myocardial reperfusion therapy. When cardiac arrest occurs, hemodynamic support with ECMO can facilitate revascularization with PCI, which can increase the time available for further salvage and treatment and reduce intraoperative risk during PCI. CASE PRESENTATION: Herein, we report a case of a 61-year-old man with AMI who suffered electrical storm of sustained malignant ventricular fibrillation, cardiogenic shock, and cardiac arrest and was successfully treated with PCI with ECMO support. During PCI, repeated aspiration and removal of the right coronary artery thrombus were performed, and blood flow was restored after right coronary artery balloon dilation. One episode of defibrillation was delivered to restore sinus rhythm. Then, stents were implanted in the distal and proximal right coronary artery lesions to achieve revascularization. After PCI with ECMO support, irreversible malignant arrhythmia returned to sinus rhythm through coronary perfusion, which prevented death following unsuccessful cardiopulmonary resuscitation. After applying active treatments, including anti-shock, mechanical ventilation, anti-inflammation, and organ support, the patient was discharged after his condition and vital signs stabilized. The patient was followed up once a week after hospital discharge, and his cardiopulmonary function recovered well. CONCLUSIONS: With ECMO support, PCI should be performed immediately in patients with inferior wall AMI complicated by electrical storm of sustained ventricular fibrillation, cardiogenic shock, and cardiac arrest to facilitate stent placement, achieve complete revascularization, restore coronary perfusion, and avoid death.

Reproductive toxicity and underlying mechanisms of fine particulate matter (PM2.5) on Caenorhabditis elegans in different seasons.

Although numerous studies have investigated that atmospheric fine particulate matter (PM2.5) can be toxic to environmental organisms, the research on the reproductive toxicity of PM2.5 is limited, and the key toxic components and underlying mechanisms remain unknown. In this work, PM2.5 samples of four seasons in Nanjing from March 1, 2021, to February 28, 2022 were collected and the chemical components were analyzed. Caenorhabditis elegans (C. elegans) was employed to conduct the toxicological testing. The reproductive toxicity of PM2.5 to C. elegans in different seasons was evaluated by multiple reproductive endpoints. Exposure to high concentrations of PM2.5 significantly decreased the brood size and the number of fertilized eggs in utero. PM2.5 exposure also increased the number of germ cell corpses and caused abnormal expression of apoptosis-related genes (ced-9, ced-4, and ced-3), which confirmed that PM2.5 induced germline apoptosis. In addition, PM2.5 exposure significantly increased the production of reactive oxygen species (ROS) in C. elegans and the fluorescence intensity of HUS-1 protein in of transgenic strain WS1433. Meanwhile, the expression of genes related to DNA damage (cep-1, clk-2, egl-1, and hus-1) and oxidative stress (mev-1, isp-1, and gas-1) also significantly altered in C. elegans, suggesting induction of DNA damage and oxidative stress. According to Pearson correlation analyses, DNA damage and oxidative stress were significantly correlated with multiple reproductive endpoints in C. elegans. Thus, it was speculated that PM2.5 caused reproductive dysfunction and germ cell apoptosis in C. elegans may be by inducing ROS and DNA damage. In addition, heavy metals in PM2.5 were significantly correlated with multiple endpoints at physiological and biochemical, suggesting that the heavy metals might be an important contributor to the reproductive toxicity induced by PM2.5.

An aggregation-induced emission immunoassay for broad detection of polychlorinated biphenyls in chicken and crab.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) with multiple variants, which may be harmful to human health by absorption and bioaccumulation. To ensure food safety, it is necessary to develop multi-residue immunoassays for broad recognition of PCBs. In this study, by mimicking the generic core structure of PCBs, three haptens have been designed and synthesized for monoclonal antibody (mAb) generation. A carboxylic acid derivative of PCB80 was a hapten that induced a mAb with broad recognition of PCBs. The results of ELISA further identified that the mAb could recognize 11 different kinds of PCBs; half-maximal inhibition concentrations (IC50) ranged from 33.12 to 476.42 ng/mL. Subsequently, using aggregation-induced emission luminogen (AIEgen) nanobeads as the tracer for the output signal, the IC50 value of the various PCBs was improved to 6.38-252.1 ng/mL. The limit of detection (LOD) varied from 0.32 to 42.15 ng/mL. Recoveries of 76.90-95.74% and intra-assay coefficients of variation of 8.5-14.4% were obtained with spiked chicken and crab meat samples. Matrix interference was eliminated by dilution, and no false-positive and false-negative results were observed. The developed assay provides a simple, broad-spectrum, and sensitive tool for detecting PCBs, with high-throughput possibilities for large-scale screening of PCBs in food.

Case Report: A Case of Unusual Combination of Hypothyroidism, Myocardial Bridging, and Myocardial Infarction-Induced Left Ventricular Aneurysm.

Background: Myocardial bridging (MB) of the coronary artery is a congenital anatomical variation, which has traditionally been considered a benign condition that does not cause cardiovascular events. However, recent studies have shown that MB is associated with major adverse cardiac events, including angina, myocardial infarction, arrhythmia, syncope, and even sudden death. Case: We report a case of a 41-year-old man who had hypothyroidism and MB associated with ventricular aneurysm following myocardial infarction. This patient was admitted to our hospital because of 11 days of sudden discomfort and pain in the chest. An electrocardiogram on admission showed an old myocardial infarction. Coronary angiography showed MB in the distal segment of the left anterior descending artery. Left ventricular angiography, which was performed using a pigtail catheter, showed ventricular aneurysm formation. Thyroid ultrasound demonstrated hypothyroidism and Hashimoto's thyroiditis. Patients with hypothyroidism and MB have a high risk of acute myocardial infarction or even sudden death. Conclusion: Observations in our case suggest that early recognition of hypothyroidism and MB is important for risk stratification and prognosis in patients with myocardial necrosis and acute coronary syndrome. Additionally, this early recognition may have positive effects on cardiovascular outcomes in patients with hypothyroidism.

The Relative Contributions of Different Chemical Components to the Oxidative Potential of Ambient Fine Particles in Nanjing Area.

Ambient fine particles (PM2.5) have been shown to have adverse health effects by inducing oxidative stress. Here, dithiothreitol (DTT)-based oxidative potential (OP) was used to assess the capacity of oxidative stress caused by PM2.5. In this study, PM2.5 samples were collected in the Nanjing area in 2016, and physicochemical properties and DTT activity were investigated. The annual mean PM2.5 mass concentration was 73 µg m-3 and greatly varied among seasons (spring > winter > summer > autumn). Three fluorescent substances were identified by the excitation-emission matrix (EEM) spectrum. The annual mean mass-normalized DTT activity (DTTm; 0.02 nmol min-1 µg-1) was similar to that documented for cities of some developed countries. The annual mean volume-normalized DTT activity (DTTv) showed a relatively high value of 1.16 nmol min-1 m-3, and the seasonal mean DTTv was highest in winter, followed by spring, autumn, and summer, whose pattern is different from PM2.5 mass concentration. Correlation and multiple linear regression analysis suggested that transition metals may have a greater effect on OP in autumn and winter, humic-like substances and UV absorbing aromatic substances may have a strong effect on OP in spring and summer. Generally, this study enhances our understanding of seasonal variation in health effects associated with PM2.5.

Rheumatic valvular heart disease combined with woven coronary artery: a case report.

BACKGROUND: Woven coronary artery (WCA) is an extremely rare congenital anomaly in which a part of epicardial coronary artery is divided into thin channels, that twist along the axis of the coronary arteries and then merge again as the main coronary lumen. This anomaly is regarded as a benign condition because the blood flow is normal. Very few cases of WCA have been reported. CASE PRESENTATION: Herein we report a case of a 44-year-old man who was admitted to our hospital due to 20 years of repeated episodes of heart palpitations, 2 years of shortness of breath after activity, and the symptoms were aggravated for 1 month. He had history of inferior myocardial infarction and atrial fibrillation. Color Doppler echocardiography revealed rheumatic heart disease, severe mitral regurgitation, mild-moderate tricuspid regurgitation, moderate pulmonary hypertension. Coronary angiography revealed 60-85% diffuse stenosis in the middle of left anterior descending artery, 60-90% diffuse stenosis in the middle of left circumflex artery, 30-40% diffuse stenosis in the proximal segment of right coronary artery, and WCA anomaly in the middle, and distal segments of right coronary artery. CONCLUSION: The patient successfully underwent prosthetic valve replacement and left anterior descending coronary artery bypass grafting, and had a good recovery after surgery. Further studies are needed to fully understand the disease and determine appropriate treatment options.

Using Deep Learning to Forecast Maritime Vessel Flows.

Forecasting vessel flows is important to the development of intelligent transportation systems in the maritime field, as real-time and accurate traffic information has favorable potential in helping a maritime authority to alleviate congestion, mitigate emission of GHG (greenhouse gases) and enhance public safety, as well as assisting individual vessel users to plan better routes and reduce additional costs due to delays. In this paper, we propose three deep learning-based solutions to forecast the inflow and outflow of vessels within a given region, including a convolutional neural network (CNN), a long short-term memory (LSTM) network, and the integration of a bidirectional LSTM network with a CNN (BDLSTM-CNN). To apply those solutions, we first divide the given maritime region into M × N grids, then we forecast the inflow and outflow for all the grids. Experimental results based on the real AIS (Automatic Identification System) data of marine vessels in Singapore demonstrate that the three deep learning-based solutions significantly outperform the conventional method in terms of mean absolute error and root mean square error, with the performance of the BDLSTM-CNN-based hybrid solution being the best.

Effect of sepsis on the action potential and cardiac serotonin response in rats.

The current study aimed to investigate the effect of sepsis on rat serotonin (5-HT) responses and cardiac action potentials. A total of 20 rats were randomly divided into a sepsis and control group (each, n=10). Rat hearts were harvested and perfused using the Langendorff method 18-h after the induction of sepsis, which was assessed using cecal puncture. Cardiac action potential was subsequently measured using a multichannel electrophysiology instrument. Immunohistochemistry and quantitative analysis were performed to identify the effect of sepsis on myocardial 5-HT expression. The results revealed that mitochondrial changes were present in septic rat hearts. Heart rate (361.10±12.29 bpm vs. 348.60±12.38 bpm; P<0.05) was significantly higher, atrial action potential duration (106.40±2.95 ms vs. 86.60±4.12 ms; P<0.01) was significantly longer and the area (0.62±0.06 µm2 vs. 0.39±0.05 µm2; P<0.05) and number (0.92±0.02/field vs. 0.46±0.01/field; P<0.01) of myocardial cells were significantly higher in the septic compared with the control group. These results demonstrated that 5-HT prolongs the atrial action potential, increases heart rate and aggravates myocardial injury, indicating that it may therefore be one of the factors that leads to cardiac dysfunction in sepsis.

Tropisetron inhibits sepsis by repressing hyper-inflammation and regulating the cardiac action potential in rat models.

OBJECTIVE: The objective of the present investigation was to explore the possible effect of the 5-HT3 receptor antagonist tropisetron on the expression levels of the inflammatory factors interleukin 6 (IL-6), creatine kinase isoenzyme (CK-MB), soluble growth stimulating gene 2 protein (sST2) and immunoglobulin E (IgE), as well as the cardiac action potential in septic rats. METHODS: The cecal ligation and perforation (CLP) method was utilized to construct abdominal infarction in rats. A total of 68 male adult Sprague Dawley rats were used, including 40 for assessing survival and 28 for detecting the expression levels of IL-6 and IgE, myocardial injury, cardiac dysfunction and the cardiac action potential. These 28 rats were divided into the sham (6 rats), sham + Tropisetron (6 rats), CLP (8 rats) and CLP + Tropisetron (8 rats) groups. Twenty-four hours after establishment of the sepsis rat model, immunohistochemistry was used to analyze 5-HT3 receptor protein expression, and enzyme-linked immunosorbent assay (ELISA) was employed to monitor the serum levels of IL-6, CKMB, sST2 and IgE. Furthermore, the structure of the myocardium in various groups was examined by H&E staining. RESULTS: The levels of IL-6, CK-MB, sST2 and IgE in the sepsis group were significantly higher than those of the sham group (P < 0.01). Furthermore, the heart rate in the sepsis group was lower than that of the sham group (P < 0.01), and the time of atrial ventricular action potential in the sepsis group was longer than that of the sham group (P < 0.05). In addition, immunohistochemical analyses showed that the area, intensity and index of 5-HT3 receptor in the sepsis group were significantly lower than those of the sham group (P < 0.01). Importantly, the 5-HT3 receptor antagonist Tropisetron exhibited significant inhibitory effects IL-6, CK-MB, sST2 and IgE expression levels, and inductive effects on atrial ventricular action potential in the sepsis group. CONCLUSIONS: Sepsis leads to systemic inflammatory reaction, resulting in myocardial injury, structural changes and immune imbalance. The inhibitory effect of tropisetron on inflammation, and the regulatory inflammatory disorder by the efferent vagus nerve may be one of the important mechanisms leading to cardiac electrophysiological changes in sepsis.

Chronic Unpredictable Mild Stress Causing Cardiac and Thoracic Spinal Cord Electrophysiological Abnormalities May Be Associated with Increased Cardiac Expression of Serotonin and Growth-Associated Protein-43 in Rats.

BACKGROUND: The aim of this study was to investigate the potential mechanisms by which chronic unpredictable mild stress (CMS) might induce cardiovascular disease. METHODS: Twenty male Sprague-Dawley rats (weighing 180-250 g) were divided into the CMS group (CMS for 3 weeks) and control group (n = 10/group). Sucrose solution consumption, sucrose solution preference rate, and the open field test (horizontal and vertical movements) were used to confirm the establishment of the CMS model. Heart rate was determined in Langendorff-perfused hearts, and field action potential duration (FAPD) was measured in cardiac atrial tissue, cardiac ventricular tissue, and thoracic spinal cord segments 1-5. The expressions of serotonin (5-HT) and growth-associated protein-43 (GAP-43) in cardiac ventricular tissue were analyzed using immunohistochemistry and immunofluorescence. RESULTS: Compared with the control group, sucrose solution consumption, sucrose solution preference rate, horizontal movement, and vertical movement were significantly lower in the CMS group (P < 0.01). The CMS group exhibited significant decreases in atrial and ventricular FAPDs (P < 0.05), as well as significant increases in heart rates (P < 0.05) and T1-5 spinal cord FAPD (P < 0.01), as compared with the control group. The expressions of 5-HT and GAP-43 in cardiac ventricular tissue were significantly higher in the CMS group than in controls (P < 0.01). CONCLUSIONS: CMS causes cardiac and T1-5 spinal cord electrophysiological abnormalities as well as increased cardiac expression of 5-HT and GAP-43, indicating that CMS could potentially increase the risk of cardiovascular disease.

[Spectral Characteristics and Catalytic Performances of SO2-4/Ce-TiO2 with Visible Light Response].

Ce doped TiO2 was prepared via sol-gel method. The as-prepared Ce doped TiO2 was impregnated with diluted H2SO4 to obtain a H2SO4-treated Ce doped TiO2. In succession, the characterizations of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), pyridine adsorption-FTIR (Py-FTIR), ultraviolet-visible spectroscopy (UV-vis) and X-ray photoelectron spectroscopy (XPS) were carried out to analyze the reasons for the improvement of the light response performance. The visible light photocatalytic degradation of Rhodamine B (RhB) in an aqueous solution was used as a probe reaction to evaluate the photocatalytic activity of the obtained samples. According to the XRD analysis, Ce doping created the lattice defects in TiO2 and minimized the particle size, which promoted the transfer of photo-generated electrons and then improved catalyst activity. The bridged bidentate coordination mode of SO2-4 was proposed based on the FTIR spectra. The pyridine FTIR spectra showed that both Lewis and Brnsted acid sites were formed on the sample surface. The characteristic absorption band as Lewis acid was more intense than that of the Brnsted acid, exhibiting the major Lewis acidity. The presence of the Lewis acid sites resulted in the transfer of photogenerated electrons to the Lewis acid center because of the electron deficiency of the Lewis acid sites, which contributed greatly to the transport of the photogenerated electrons, inhibiting the recombination of the photogenerated electron/hole pairs and leading to the enhancement of the photocatalytic activity of samples. From UV-Vis results, Ce-doping introduced an impurity energy level in the band gap, narrowing the TiO2 band gap. The impurity energy level could capture the photogenerated electrons on the conduct band and photogenerated holes on the valence band, reducing the recombination probability of photogenerated carriers and exciting the electrons captured on the impurity energy band by the photons with lower energy, thus expanding the light response range of TiO2. The XPS results indicated that the doped Ce existed as a mixture of Ce3+/Ce4+ states, which facilitated the efficient separation of the photo-generated electrons and holes because of the electron transfer, enhancing the system's quantum efficiency. The sulfated Ce doped TiO2 catalysts were very active for the visible photocatalytic degradation of RhB. Results showed that the synergetic effects of Ce doping and acid-treatment improved the visible light response for sulfated Ce-doped TiO2, enhancing the visible photocatalytic activity.

Investigation of the alterations in cellular electrophysiology underlying ventricular arrhythmia in dogs with the multiple organ dysfunction syndrome.

BACKGROUND: Multiple organ dysfunction syndrome (MODS)-specific cellular electrophysiological changes have so far not been reported and it seemed unlikely that they were related to arrhythmogenesis. METHODS AND RESULTS: Twelve dogs, weight 12 +/- 2 kg, were divided into a control group (n = 6) and an MODS group (n = 6). MODS lasting for 72 h was induced by the 'two-hit' method in 6 dogs. Ventricular myocytes were enzymatically isolated. Early afterdepolarizations (EADs), action potential duration (APD) and L-type calcium currents (ICa,L) were assessed. Sinus arrhythmias in all MODS dogs (100%; 6 of 6) and premature ventricular beats in 4 MODS dogs (66%; 4 of 6) were recorded, while no arrhythmias were found in the control animals. The prolongation of the APD was associated with a decreased ICa,L, and frequently provoked EADs were the typical electrophysiological alterations in the myocytes of MODS dogs. The action potential prolongation was shortened, the ICa,L blocked and EAD suppressed by using verapamil (100 micromol/l) in the myocytes of MODS dogs (66%; 4 of 6). CONCLUSION: The changes in cellular electrophysiology within 72 h in the heart of MODS dogs are APD prolongation, markedly decreased ICa,L as well as frequently provoked EAD, the most common types of arrhythmia being sinus arrhythmia and premature ventricular beats. This study suggests that verapamil appears to be an effective agent in reversing alterations in cellular electrophysiology at the early stage of MODS.

[Microelectrode arrays mapped tissue field action potential duration changes of thoracic spinal cord 1 - 5 nerves and heart in chronic stress rat model].

OBJECTIVE: To investigate chronic stress induced tissue action potential and pathological changes of thoracic spinal cord 1 - 5 nerves and heart in SD rats. METHODS: SD rats (weighing 180 - 250 g) were randomly divided into depressive group and control group (n = 10 each). Depressive model (unpredicted chronic mild stress) was established according to Gronli's protocol. The heart rhythm, tissue field action potential duration (FAPD) of thoracic spinal cord 1 - 5 nerves, atrium and ventricle were mapped by microelectrode arrays (MEA) technique. Heart was sectioned and stained with Massion and HE for pathological analysis. RESULTS: After 3 weeks chronic stress, P wave [(35.09 +/- 7.92) ms vs. (25.43 +/- 3.38) ms, P<0.05] and Q-T interval [(114.64 +/- 35.08) ms vs. (81.93 +/- 16.35) ms, P<0.01] were significantly increased, FAPD of thoracic spinal cord 1 - 5 nerves and heart was significantly prolonged, atrial field action potential duration dispersion (FAPDd) was significantly increased, atrial premature beats (n = 2) and ventricular premature beats ( n = 3) were also recorded in rats from depressive group. Moreover, increased collagen deposition was evidenced in Massion stained myocardium and increased inflammatory cell infiltration in the heart was found by both HE stain and electron microscope from depressive rats. CONCLUSION: Chronic mild stress could activate sympathetic nerves system, promote inflammatory cell myocardial infiltration and myocardial fibrosis, induce arrhythmias by prolonging FAPD and increasing FADPd in thoracic spinal cord 1 - 5 nerves and/or heart tissue.

ACh-evoked membrane hyperpolarization in smooth muscle cells of rat vas deferens in vitro: involvement of K(+) channels and NO.

To explore the underlying mechanism of acetylcholine (ACh)-evoked membrane hyperpolarizing response in isolated rat vas deferens smooth muscle cells (SMCs), intracellular microelectrode recording technique and intracellular microelectrophoresis fluorescent staining technique were used to study ACh-evoked membrane hyperpolarizing response in SMCs freshly isolated from Wistar rat vas deferens. By using microelectrodes containing fluorescent dye 0.1% propidium iodide (PI), 37 and 17 cells were identified as SMCs in outer longitudinal and inner circular muscular layers, respectively. The resting membrane potentials of SMCs were (-53.56+/-3.88) mV and (-51.62+/-4.27) mV, respectively. The membrane input resistances were (2245.60+/-372.50) MOmega and (2101.50+/-513.50) MOmega, respectively. ACh evoked membrane hyperpolarizing response in a concentration-dependent manner with an EC(50) of 36 micromol/L. This action of ACh was abolished by both a non-sepcific muscarinic (M) receptor antagonist atropine (1 mumol/L) and a selective M(3 ) receptor antagonist diphenylacetoxy-N-methylpiperidine-methiodide (DAMP, 100 nmol/L). ACh-evoked membrane hyperpolarization was also abolished by a nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME, 300 micromol/L) and suppressed by an ATP-sensitive potassium (K(ATP)) channel blocker glipizide (5 micromol/L) and an inward rectifier potassium (K(ir)) channel inhibitor bariumion (50 micromol/L). A combination of glipizide and bariumion abolished ACh-evoked membrane hyperpolarizing response. The results suggest that ACh-evoked membrane hyperpolarization in rat vas deferens SMCs is mediated by M(3) receptor followed with activation of K(ATP) channels, K(ir) channels, and NO release.

[Effects of chloride channel blockers on excitatory junction potentials in smooth muscle cells of cochlear spiral modiolar artery in guinea pigs].

Chloride channels have been identified in vascular smooth muscle cells (SMCs). It has been shown that these channels are involved in myogenic tone regulation and neuromuscular transmission in various vascular beds. However, whether the chloride channels are responsible for the formation of excitatory junction potentials (EJPs) of SMCs in the spiral modiolar artery (SMA) remains unelucidated. In the present study, the effects of chloride channel blockers (niflumic acid, NFA; indanyloxyacetic acid 94, IAA-94; disodium 4, 4'-diisothiocyanatostilbene-2, 2'-disulfonate, DIDS) on EJP were explored in guinea pigs, using intracellular recording techniques on acutely isolated SMA. It was found that EJP was evoked in the majority of the SMCs (75%, n=49) with an adequate electronic stimulation. The amplitude of the EJP was partially blocked (30% approximately 80%) by combined application of alpha(1) receptor antagonist (prazosin) and alpha(2) receptor antagonist (idazoxan) at concentration of up to 1 micromol/L, and P(2x) receptor antagonist (PPADS, 10 approximately 100 micromol/L). NFA (100 micromol/L) could further inhibit the residual EJP in the presence of alpha(1), alpha(2)-adrenergic and P(2x) receptor antagonists. IAA-94 or DIDS not only inhibited the amplitude but also shortened the duration of EJP. Decrease of extracellular chloride concentration from 135.6 mmol/L to 60 mmol/L would enhance EJP. Moreover, IAA-94 (100 micromol/L) and DIDS (200 mumol/L) could reverse the enhancement of EJP by low extracellular Cl(-). NFA (100 micromol/L) could also block the residual depolarizations evoked by norepinephrine (NE, 1 approximately 50 micromol/L). Based on these results, it is inferred that NE could activate a novel adrenoceptor to open the chloride channel on the membrane of the SMCs, leading to a transmembrane Cl(-) current. This current is involved, at least partially, in the formation of EJP.