ABSTRACT
BACKGROUND: One of the major unresolved issues in treating pain is the paradoxical hyperalgesia produced by opiates, and accumulating evidence implicate that EphBs receptors and ephrinBs ligands are involved in mediation of spinal nociceptive information and central sensitization, but the manner in which ephrinB/EphB signalling acts on spinal nociceptive information networks to produce hyperalgesia remains enigmatic. The objective of this research was to investigate the role of ephrinB/EphB signalling in remifentanil-induced hyperalgesia (RIH) and its downstream effector. METHODS: We characterized the remifentanil-induced pain behaviours by evaluating thermal hyperalgesia and mechanical allodynia in a rat hind paw incisional model. Protein expression of EphB1 receptor and ephrinB1 ligand in spinal dorsal horn cord was determined by Western blotting, and Fos was determined by immunohistochemistry assay, respectively. To figure out the manner in which ephrinB/EphB signalling acts with N-methyl-d-aspartic acid (NMDA) receptor, we used MK-801, an antagonist of NMDA receptor, trying to suppressed the hyperalgesia induced by ephrinB1-Fc, an agonist of ephrinB/EphB. RESULTS: Continuing infusion of remifentanil produced a thermal hyperalgesia and mechanical allodynia, which was accompanied with increased protein expression of spinal-level EphB1 receptor, ephrinB1 ligand and Fos; what appeared above was suppressed by pretreatment with EphB1-Fc, an antagonist of ephrinB/EphB or MK-801, and increased pain behaviours induced by intrathecal injection of ephrinB1-Fc, an agonist of ephrinB/EphB, were suppressed by MK-801. CONCLUSIONS: Our findings indicated that ephrinB/EphB signalling is involved in RIH. EphrinB/EphB signalling might be the upstream of NMDA receptor.
Subject(s)
Analgesics, Opioid/pharmacology , Ephrin-B1/metabolism , Hyperalgesia/chemically induced , Piperidines/pharmacology , Receptor, EphB1/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Signal Transduction/physiology , Analgesics, Opioid/adverse effects , Animals , Disease Models, Animal , Dizocilpine Maleate/pharmacology , Ephrin-B1/agonists , Ephrin-B1/antagonists & inhibitors , Excitatory Amino Acid Antagonists/pharmacology , Male , Piperidines/adverse effects , Rats , Rats, Sprague-Dawley , Receptor, EphB1/agonists , Receptor, EphB1/antagonists & inhibitors , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , RemifentanilABSTRACT
The potential energy surface (PES) of the CH3OH system has been characterized by ab initio molecular orbital theory calculations at the G2M level of theory. The mechanisms for the decomposition of CH3OH and the related bimolecular reactions, CH3 + OH and 1CH2 + H2O, have been elucidated. The rate constants for these processes have been calculated using variational RRKM theory and compared with available experimental data. The total decomposition rate constants of CH3OH at the high- and low-pressure limits can be represented by k infinity = 1.56 x 10(16) exp(-44,310/T) s-1 and kAr0 = 1.60 x 10(36) T-12.2 exp(-48,140/T) cm3 molecule-1 s-1, respectively, covering the temperature range 1000-3000 K, in reasonable agreement with the experimental values. Our results indicate that the product branching ratios are strongly pressure dependent, with the production of CH3 + OH and 1CH2 + H2O dominant under high (P > 10(3) Torr) and low (P < 1 atm) pressures, respectively. For the bimolecular reaction of CH3 and OH, the total rate constant and the yields of 1CH2 + H2O and H2 + HCOH at lower pressures (P < 5 Torr) could be reasonably accounted for by the theory. For the reaction of 1CH2 with H2O, both the yield of CH3 + OH and the total rate constant could also be satisfactorily predicted theoretically. The production of 3CH2 + H2O by the singlet to triplet surface crossing, predicted to occur at 4.3 kcal mol-1 above the H2C...OH2 van der Waals complex (which lies 82.7 kcal mol-1 above CH3OH), was neglected in our calculations.
ABSTRACT
OBJECTIVE: To testify the availability and the clinical efficacy of the skin-stretching device. METHODS: The skin-stretching device designed by ZHOU Li-an, which was used in the treatment of the granulation wound, the donor site of flap, and the skin defect after the excision of tumor by skin traction technique at the wound edges. RESULTS: The usage time of skin-stretching device was 15-720 minutes, it could be used preoperatively, intraoperatively and postoperatively. Followed up 16 cases for 6 to 12 months, the device was effective. CONCLUSION: The skin stretching device is practical and effective in wound closure of skin defect.
