AIM: To study the effects of nitric oxide (NO) on mitochondrial damage caused by exogenous calcium. METHODS: Normal myocardial mitochondria were divided into three groups; L- arginine control group (CG), Ca2 + - damaged group (DG) and L - NAME - preserved group (PG). Mitochondria of all groups were incubated at 30℃ with reaction medium containing 20μmol/L EDTA, 100μmol/L CaC12 and 1 μmol/L L- NAME with 100μmol/L CaCl2 respectively. Then the NO2-/NO3- contents, mitochondrial viability and membrane potential were investigated. RESULTS: The NO2-/NO3 contents of DG was obviously higher than that of CG and PG, meanwhile, there was no obvious difference between CG and PG. Mitochondrial viability and membrane potential of DG were significantly lower than that of CG and PG, and negatively related to NO2-/NO3- contents ( r = - 0.5297, P < 0.01; r = -0.6041, P < 0.01 ). But, the mitochondrial viability and membrane potential of PG were still lower than that of CG. CONCLUSION: Exogenous calcium could activate mitochondrial nitric oxide synthase resulting in NO production and the latter play an important role in decreasing mitochondrial viability and membrane potential.

Objective To investigate the changes of myocardial mitochondrial permeability transition pore(PTP) and its mechanism in the early stage after severe burns. Methods An experimental model of 30% TBSA full thickness skin scalding was established in rats. All rats were injected with deoxyglucose(DOG) before sacrifice. Myocardial mitochondrial DOG and cytochrome c content, Ca 2+ concentration([Ca 2+ ] m) and MDA content were determined. Results ① There were no obvious changes of mitochondrial DOG and cytochrome c content at 1 h after burns, but mitochondrial DOG increased evidently at 3, 6, 12 and 24 h after burns. Meanwhile, cytochrome c content was significantly lower than that of the control, being 68.8%, 50.0%, 77.1% and 72.9% of that in the control, respectively. ② [Ca 2+ ] m and MDA content were significantly higher than those of the control at 3, 6, 12 and 24 h after burns. ③ Mitochondrial DOG content was positively correlated with [Ca 2+ ] m and MDA content, respectively, after burns. Conclusion There is no obvious change in myocardial mitochondrial permeability transition pore, but PTP opening increases markedly at 3, 6, 12 and 24 h after burns. Mitochondrial Ca 2+ overloading and increase in free radicals may be the cause leading to PTP opening.

Objective To investigate the roles of the activated p38 kinase in cell injury by observation of the effects of hypoxia and burn serum on cardiomyocyte p38 kinase and JNK activation. Methods Phosphorylation of p38 kinase and JNK in primary cultured neonatal rat cardiomyocytes before and after hypoxia and burn serum was determined by Western blotting. Effects of pretreatment with SB203580 at the dose of 10 ?mol/L on the changes of phosphorylation of p38 kinase in cardiomyocytes, lactate dehydrogenase (LDH) activity, cell vitality and apoptosis were investigated, respectively. Results Exposure of rat neonatal cardiomyocytes to hypoxia and burn serum resulted in a rapid and long lasting activation of p38 kinase but no significant activation of JNK. SB203580(10 ?mol/l), a selective inhibitor of p38 kinase, could inhibit p38 kinase activation dramatically, decrease the LDH activity in culture media and cell apoptosis significantly and improve cell vitality. Conclusion In the two stress activated signal pathways of MAPKs family, p38 kinase pathway, but not JNK, is the major pathway activated by hypoxia and burn serum and participates in the cardiomyocyte injury.

Objective To investigate the protective effects of diazoxide on cardiomyocytes after severe burn injury Methods A total of 24 healthy Wistar rats were randomized into normal control group(Control), burn group(Burn) and diazoxide treated group(Diazo)( n =8) Rats in Burn and Diazo groups were inflicted with 30%TBSA Ⅲ degree burn and resuscitated with Ringer's solution intraperitoneally 30 min after burn Diazoxide was injected into rats in Diazo group at the dose of 10 mg/kg through the external jugular vein After rats were sacrificed at 6 h after burn, myocardial mitochondrial K + influx, respiratory function, Ca 2+ concentration ([Ca 2+ ]m), MDA content, serum CK and LDH levels were determined Results Mitochondrial K + influx of Diazo group was evidently higher than that in Control and Burn group Mitochondrial respiratory control rate(RCR) and ST 3 in Diazo group were higher than that in Burn group However, [Ca 2+ ]m, MDA, CK and LDH levels in Diazo group were significantly lower than those in Burn group Conclusion Diazoxide can attenuate the damage to cardiomyocytes after severe burn injury, which might be related to the opening of mitochondrial K + channel, inhibition of mitochondria from Ca 2+ overloading and decrease of free radical production

AIM: To study the effects of nitric oxide (NO) on mitochondrial damage caused by exogenous calcium. METHODS: Normal myocardial mitochondria were divided into three groups; L-arginine control group (CG), Ca 2+-damaged group (DG) and L-NAME-preserved group (PG). Mitochondria of all groups were incubated at 30℃ with reaction medium containing 20 ?mol/L EDTA, 100 ?mol/L CaCl 2 and 1 ?mol/L L-NAME with 100 ?mol/L CaCl 2 respectively. Then the NO- 2/NO- 3 contents, mitochondrial viability and membrane potential were investigated.RESULTS: The NO- 2/NO- 3 contents of DG was obviously higher than that of CG and PG, meanwhile, there was no obvious difference between CG and PG. Mitochondrial viability and membrane potential of DG were significantly lower than that of CG and PG, and negatively related to NO- 2/NO- 3 contents (r=-0.5297, P

Objective To explore the effect of MMP-1, TIMP-1 on burn wound healing and hypertrophic scar (HS) forming. Methods Normal human full-thickness skin grafts were transplanted to the back of nude (athymic) mice, after these grafts survived, deep Ⅱ degree burn wounds were made in the middle of these grafts. During the process of burn wound healing and HS formation, the expressions of MMP-1 and TIMP-1 were detected by immunohistochemical staining. Results MMP-1 expression was first noted by day 2 after burns and became more prominent from day 3 to day 15, and then decreased rapidly. Immunostaining for MMP-1 was markedly increased at boundary regions marked by connective tissue fluidity. Immunoreactive TIMP-1 was also detected by day 2 but rapidly assumed the same interface expression pattern as described for MMP-1. Compared with MMP-1, immunostaining of TIMP-1 was irregular, but was obvious around vascular tissues. Conclusions The balance between MMP-1 and TIMP-1 during the inflammation and granulation phases might be important for the regulation of collagen proteins degradation. Within the remodeling phase, the inhibition of MMP-1 by TIMP-1 and the decrease of collagen degradation might lead to HS forming. The striking immunolocalization of MMP-1 and TIMP-1 to epithelial-dermal, eschar-dermal, and vascular-dermal interfaces suggested that they might play a particularly significant role at boundary regions marked by connective tissue fluidity.

Objective To explore a suitable plan for the delayed rapid fluid resuscitation in burn patients with shock. Methods 20 patients with total body surface area (TBSA) burned over 40% admitted 4～8h after postburn were enrolled in this study. The patients were randomly divided into plasma and gelofusin groups. Rapid fluid replacement was given immediately after admission under close hemodynamic monitoring. Hemodynamic (PAP, PAWP, CO, PVR, SVR) and hemorrheological parameters, tissue oxygenation (DO 2, VO 2, O 2ext , lactic acid, base deficit) as well as indices reflecting the main visceral functions and damage were investigated. Results The amount of rapid fluid infusion within 2h after admission accounted for 38 8?6 1% of the amount calculated with the formula for the first 24h. When the infusion amount of pre-hospitalization was added, the amount would be (48 3?5 0)% of the amount for the first 24h. The real amount of the infusion for the first 24h was (31 4?14 3)% more than that of the amount calculated with the Evans formula. The real infused fluid amount for the second 24h was almost equal to the amount calculated with the formula. After fast fluid replacement therapy, all the parameters determined were markedly improved. Conclusions It is proposed that the formula for the delayed rapid fluid resuscitation in burn patients with shock should be: the amount infused for the first 24h (ml) =TBSA (%)?body weight (kg)?2 6,the ratio of colloid to electrolytes is 1:1, water=2000ml. Half of the total amount should be infused in the first 2h after admission under close hemodynamic monitoring. The amount infused for the second 24h (ml)=TBSA (%)?body weight (kg)?1,the ratio of colloid to electrolytes is 1:1, water=2000m1.

Objective:To revise the Psychological Security-insecurity Questionnaire(S-I) developed by Maslow and examine its reliability and validity.Methods:Data were collected from 1893 junior middle school students with the original S-I.Results:The revised S-I consisted of 44 items,including 10 first-order factors and 3 second-order factors.It had good test-retest reliability,homogeneity reliability and criterion validity.Conclusion:The revised S-I has satisfying reliabilities and validities,and is suitable to asses the psychological security and insecurity for Chinese junior school students.

The serial changes in thromboxane (TXA2) prostacyclin(PGI2),circulatory platelet aggregate ratio (CPAR),platelet count,blood viscosity,myocardial enzyme spectrum,cortisol and epinephrine were determined in 42 severely burnt patients randomly divided into two groups.The findings demonstrated that in the control group,both TXA2 and TXA2/PGI2 ratio increased significantly during the early postburn stage.Myocardial enzyme spectrum,blood viscosity,cortisol and epinephrine also increased markedly.However,levels of the above parameters in the anisodamine-treated group were significantly lower than in the control following the infusion of anisodamine.On the contrary,CPAR and platelet count in the treated group increased and were significantly higher than those in the control.Moreover,TXA2 was closely correlated with CPAR,platelet count,blood viscosity and myocardial enzyme spectrum (P

Forty-one burn patients were divided into inhalation injury and non-inhalation injury groups.It was found that in the inhalation injury group,TXB2 level and TXB2/G-keto-PGF1? ratio in plasma and lung tissue were significantly elevated,circulatory platelet aggregate ratio markedly decreased,and blood viscosity greatly increased.Histopathologically,congestion,edema,hemorrhage and thrombosis were seen in lung tissue.The changes of TXB2 level and TXB2/6-keto-PGF1?ratio were parallel to the clinical course of the development of respiratory failure in the patients with body surface burns complicated with inhalation injury.It is believed that the imbalance of TXA2/PGI2 is one of the factors of respiratory failure in severe body surface burns complicated with inhalation injury.