Mechanisms of bupivacaine inhibition of glutamate-induced intracellular calcium elevation in primary cultured rat hippocampal astrocytes / 药学学报

This research investigated the mechanism by which bupivacaine inhibits glutamate-induced intracellular free Ca2+ increases in primary cultured hippocampal astrocytes. Immunofluorescence was used to demonstrate the expression of metabotropic glutamate receptor (mGluR5 receptor) on neurons and astrocytes. Calcium imaging was used to measure the alteration of intracellular free Ca2+ ([Ca2+]i) in primary cultured rat hippocampal neurons and astrocytes. The animal experiments were approved by the Animal Experiments Ethical Committee of Hebei Medical University. The results showed that mGluR5 receptor was abundantly expressed in the primary cultured rat neurons and astrocytes. Bupivacaine (300 μmol·L-1) significantly inhibited 1 mmol·L-1 glutamate-induced [Ca2+]i increase in astrocytes (P < 0.01). 2-Methyl-6-(2-phenylethynyl)-pyridine (MPEP) (10 μmol·L-1) completely abolished the increase of [Ca2+]i induced by 1 mmol·L-1 glutamate in the astrocytes (P < 0.01), while the inhibitory effect on neurons was only 10%-20%. Bupivacaine (300 μmol·L-1) completely inhibited the [Ca2+]i increase induced by mGluR5 receptor agonists (RS)-3,5-dihydroxyphenylglycine (DHPG) (50 μmol·L-1) and (RS)-2-chloro-5-hydroxyphenylglycine sodium salt (CHPG) (1 mmol·L-1) in astrocytes (P < 0.01). In addition, bupivacaine inhibited the CHPG-induced [Ca2+]i increase in a dose-dependent manner in astrocytes with an IC50 of 100 μmol·L-1. The results from this study indicate that bupivacaine inhibits glutamate-induced [Ca2+]i elevation by acting on the mGluR5 receptor in primary cultured hippocampal astrocytes.

Detection of the viscoelasticity of relaxed myocardium in vivo by intervention ultrasound indentation system / 解放军医学杂志

Objective To explore the viscoelasticity of relaxed myocardium in vivo through indentation method with an intervention ultrasound indentation system (IUIS). Methods Old myocardial infarction (OMI) models of canine were established by ligating left anterior descending branch of coronary artery for 3 months. The indentation creep tests were used respectively in OMI group and shame group (n=8, each) by IUIS in middle and advanced diastole stage in vivo. Test data were processed with three-parameter solid viscoelasticity model, and the viscoelastic parameters, such as instantaneous elastic modulus (E1), relaxation modulus (E∞), creep elastic modulus (E2) and viscous damping coefficient (η) in normal and infarcted myocardium were obtained and compared. Results All the parameters of E1, E∞, E2 and η increased obviously in OMI group than in sham group shown as follows: 27.81±6.74kPa vs. 6.78±2.43kPa; 17.87±3.59kPa vs. 4.52±1.56kPa; 49.54±14.35kPa vs. 16.82±12.37kPa and 1.97±0.78Pa.s vs. 0.66±0.40Pa.s. The differences were statistically significant (P<0.05). Conclusions IUIS is a feasible method to assess the viscoelasticity of relaxed myocardium in vivo. Three-parameter viscoelasticity model can be used to describe creep properties of relaxed myocardium. Both elastic modulus and viscosity resistance have increased in infarcted myocardium.

How to guide students out of dilemma in clinical training for young teachers / 中华医学教育探索杂志

Based on a small-scale questionnaire survey, the study analyzed the dilemma of medical students in clinical training, discussing how young teachers should guide the students get out of the dilemma, including how to resolve the conflict between further study and career, acquire more practicing opportunity, improve their communication ability with patients, and value their lives finally.