Entropy and Entransy Dissipation Analysis of a Basic Organic Rankine Cycles (ORCs) to Recover Low-Grade Waste Heat Using Mixture Working Fluids.

Mixture working fluids can reduce effectively energy loss at heat sources and heat sinks, and therefore enhance the organic Rankine cycle (ORC) performance. The entropy and entransy dissipation analyses of a basic ORC system to recover low-grade waste heat using three mixture working fluids (R245fa/R227ea, R245fa/R152a and R245fa/pentane) have been investigated in this study. The basic ORC includes four components: an expander, a condenser, a pump and an evaporator. The heat source temperature is 120 °C while the condenser temperature is 20 °C. The effects of four operating parameters (evaporator outlet temperature, condenser temperature, pinch point temperature difference, degree of superheat), as well as the mass fraction, on entransy dissipation and entropy generation were examined. Results demonstrated that the entransy dissipation is insensitive to the mass fraction of R245fa. The entropy generation distributions at the evaporator for R245/pentane, R245fa/R152a and R245fa/R227ea are in ranges of 66-74%, 68-80% and 66-75%, respectively, with the corresponding entropy generation at the condenser ranges of 13-21%, 4-17% and 11-21%, respectively, while those at the expander for R245/pentane, R245fa/R152a and R245fa/R227ea are approaching 13%, 15% and 14%, respectively. The optimal mass fraction of R245fa for the minimum entropy generation is 0.6 using R245fa/R152a.

Comparison of the pharmacokinetics of linezolid in burn and non-burn rabbits.

Linezolid is effective on many resistant organisms for the treatment of severe infections in burns. However, its pharmacokinetics was difficult to predict after major burns. The study aimed to describe the pharmacokinetic properties of linezolid administered intravenously at a dose of 10 mg/kg in severely burned rabbits in comparison to that in non-burns. Linezolid concentrations were quantitatively analyzed by high-performance liquid chromatography. The direct consequence of the physiological changes after burn injury was lower plasma linezolid concentrations. In addition, burn injury induced significantly altered pharmacokinetic parameters with higher inter-individual variability. The distribution volume and clearance rate were increased (2.88 vs. 1.92 L/kg, P > 0.05; 0.28 vs. 0.20 L/h/kg, P < 0.05), and the AUC0-∞ was significantly lower (37.99 vs. 51.47 mg/L h, P < 0.05). However, there were almost no changes in half-life and mean residence time. These results suggested that therapeutic drug monitoring and dosage individualization of linezolid in patients with severe burns were necessary.

[Voltage dependent anion channel 2 involved mitochondrial apoptosis and its possible regulatory signal pathway in hearts of rats with severe scalds].

OBJECTIVE: To explore the role of voltage dependent anion channel 2 (VDAC2) involved mitochondrial apoptosis in heart injury of rats with severe scald injury and elucidate its possible regulatory signal pathway. METHODS: A total of 60 Wistar rats were divided into sham scald group (n = 30) and scald group (n = 30) according to a random digital table. Blood and heart tissue samples were harvested at Day 1, 7, 14 post scalding. Myocardial injury was assessed with cardiac troponin I (cTnI) by enzyme-linked immunosorbent assay (ELISA). Mitochondrial apoptosis activation was evaluated by the expressions of Bax/Bcl-2 ratio, cytoplasmic cytochrome C and VDAC2. And the levels of phosphatidylinositol 3-kinase, p-Glycogen Synthase Kinase-3ß and hexokinase 2 protein were determined by Western blot. RESULTS: The serum levels of cTnI were significantly higher in scald group than those in sham scald group at Day 1, 7, 14 ((1.41 ± 0.25) vs (0.53 ± 0.23) µg/L, (1.93 ± 0.53) vs (0.43 ± 0.23) µg/L, (1.62 ± 0.34) vs (0.41 ± 0.22) µg/L respectively, all P < 0.05). Compared with sham scald group, Bax/Bcl-2 ratio increased significantly in scald group at Day 1, 7 day post-scalding (3.360 ± 0.173 vs 0.623 ± 0.044, 2.736 ± 0.341 vs 0.698 ± 0.064, 1.290 ± 0.234 vs 0.718 ± 0.063 respectively, all P < 0.05), VDAC2 protein level in scald group decreased significantly at Day 1, 7, 14 (0.070 ± 0.009 vs 0.328 ± 0.026, 0.007 ± 0.002 vs 0.291 ± 0.025, 0.009 ± 0.004 vs 0.302 ± 0.037 respectively, all P < 0.05), the cytoplasmic levels of cytochrome increased significantly in scald group at Day 1, 7, 14 (0.418 ± 0.030 vs 0.022 ± 0.007, 1.685 ± 0.169 vs 0.030 ± 0.011, 0.300 ± 0.037 vs 0.098 ± 0.014 respectively, all P < 0.05), the expression of PI3K was significantly lower in scald group at Day 14 post-scalding (0.083 ± 0.015 vs 0.328 ± 0.011, P < 0.05), the expressions of p-GSK3ß all reduced significantly at Day 1, 7, 14 (0.098 ± 0.014 vs 0.446 ± 0.031, 0.064 ± 0.002 vs 0.476 ± 0.054, 0.074 ± 0.010 vs 0.442 ± 0.041, respectively, all P < 0.05) and the expressions of HK2 were lower at Day 7, 14 post-scalding (0.390 ± 0.027 vs 0.611 ± 0.070, 0.267 ± 0.018 vs 0.490 ± 0.042, respectively, all P < 0.05). CONCLUSIONS: VDAC2 involved mitochondrial apoptosis is activated in myocardium after severe scalds. And it may be regulated by the pathway of PI3K-GSK-HK2.

[Changes in cytokines in lymph and T lymphocyte subsets in lymph node of burned rats].

OBJECTIVE: To observe the effect of burn on cytokines in lymph and T lymphocyte subsets in lymph node of rats. METHODS: Eighteen Wistar rats were used in the experiment. One of the hind limbs of each rat was immersed in 70 °C hot water for 30 s to reproduce 4%TBSA deep partial-thickness scald model (burn group), while the other hind limb was immersed in 22 °C warm water for 30 s to simulate scald (sham injury group). On post injury hour (PIH) 6, 24, and 72, 6 rats were chosen according to the random number table. Lymph fluid in the lymph vessel of each animal (two groups) was obtained for determination of levels of tumor necrosis factor α (TNF-α), interferon-γ (IFN-γ) and interleukin-4 (IL-4) by ELISA, and IFN-γ/IL-4 ratio was calculated. Common iliac lymph node of each animal (two groups) was obtained for determination of ratios of CD4(+), CD8(+)T lymphocytes with flow cytometry, and CD4(+)/CD8(+) ratio was calculated. Data were processed with t test. RESULTS: (1) On PIH 6, 24, and 72, TNF-α level in burn group was respectively (51.6 ± 5.4), (27.4 ± 2.6), (23.0 ± 2.7) pg/mL, which were significantly higher than those in sham injury group [(17.8 ± 1.6), (16.4 ± 1.2), (17.2 ± 2.0) pg/mL, with t value respectively 15.346, 11.854, 4.189, P values all below 0.01]. (2) On PIH 6, 24, and 72, there was no significant statistical difference between burn group and sham injury group in IFN-γ level (with t value respectively 2.059, -0.805, -0.415, P values all above 0.05); IL-4 level in burn group was respectively higher than that in sham injury group (with t value respectively 9.141, 11.669, 6.940, P values all below 0.01); IFN-γ/IL-4 ratio in burn group (2.27 ± 0.34, 1.54 ± 0.19, 1.60 ± 0.16) was respectively lower than that in sham injury group (3.33 ± 0.25, 3.34 ± 0.22, 2.52 ± 0.24, with t value respectively -6.298, -11.313, -8.893, P values all below 0.01). (3) On PIH 6 and 24, there was no significant statistical difference between burn group and sham injury group in ratios of CD4(+) and CD8(+)T lymphocytes and also CD4(+)/CD8(+) ratio (with t values from -2.486 to -0.215, P values all above 0.05). On PIH 72, ratio of CD4(+)T lymphocytes and CD4(+)/CD8(+) ratio in burn group was respectively (38.6 ± 2.3)% and 2.13 ± 0.16, which were significantly lower than those in sham injury group [(48.9 ± 2.9)% and 2.68 ± 0.12, with t value respectively -7.551, -5.068, P values below 0.01]; there was no significant statistical difference between burn group and sham injury group in ratio of CD8(+)T lymphocytes (t = 0.845, P > 0.05). CONCLUSIONS: Burn may decrease IFN-γ/IL-4 ratio in locally drained lymph and CD4(+)/CD8(+) ratio in locally drained lymph node of rat, which may indicate lowering of local immune function.

[Expressions of endoplasmic reticulum stress associated proteins in livers of severely burned rats].

OBJECTIVE: To explore the expression of endoplasmic reticulum stress (ERS) associated proteins in livers of severely burned rats and examine its potential significance. METHODS: Sixty-four Wistar rats were randomly divided into the control and burn groups (30% total body surface area full-thickness thermal injury) (n = 32 each). Livers were harvested at Day 1, 4, 7, 14 post-burn. Western blot was used to detect the expressions of endoplasmic reticulum stress associated proteins glucose regulated protein 78 (GRP78), C/EBP-homologous protein (CHOP), active caspase-12 and active caspase-3. Hepatic apoptosis was assessed by the assay of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). RESULTS: Compared with the control group, the expression of GRP78 became elevated at Day 1, 4, 7, 14 post-burn (1.29 ± 0.11 vs 1.00 ± 0.00, 1.28 ± 0.12 vs 0.95 ± 0.16, 1.29 ± 0.14 vs 0.93 ± 0.06, 1.41 ± 0.17 vs 1.02 ± 0.13 respectively); the expression of CHOP was higher at Day 1, 4 (1.72 ± 0.07 vs 1.00 ± 0.00, 1.82 ± 0.18 vs 1.46 ± 0.08 respectively) while active caspase-12 and active caspase-3 increased at Day 1, 4, 7 post-burn (2.05 ± 0.65 vs 1.00 ± 0.00, 2.16 ± 0.69 vs 0.95 ± 0.21, 1.98 ± 0.56 vs 0.90 ± 0.22; 1.96 ± 0.15 vs 1.00 ± 0.00, 1.40 ± 0.14 vs 1.07 ± 0.12, 1.77 ± 0.17 vs 1.15 ± 0.21 respectively); the apoptotic index(%) of hepatocytes was higher at Day 1, 4, 7, 14 post-burn (27.20 ± 3.63 vs 5.00 ± 0.71, 16.40 ± 1.52 vs 5.40 ± 1.14, 27.60 ± 1.82 vs 7.40 ± 1.14, 10.20 ± 1.92 vs 5.20 ± 1.64 respectively). All results were statistically significant (all P < 0.05). CONCLUSION: ERS activates and expressions of associated proteins GRP78, CHOP, active caspase-12 and active caspase-3 increase in livers of severely burned rats.

[Clinical observations of negative pressure wound therapy and basic fibroblast growth factor in the treatment of intractable pressure ulcer].

OBJECTIVE: To observe the clinical efficacies and costs of negative pressure wound therapy (NPWT) and basic fibroblast growth factor (bFGF) in the treatment of stage III or IV pressure ulcer (PU). METHODS: From July 2008 to December 2011, 48 patients fulfilling the study inclusion or exclusion criteria at Weihai Municipal Hospital were divided randomly into experiment and control groups (n=24 each). On the basis of routine treatment and NPWT of each inpatient, the patients in the experiment group were treated with bFGF. The changes of healing rate of PU were measured at Days 7 and 14 post-treatment in each group. Meanwhile, the granulation duration, preoperative time and total preoperative cost were compared. RESULTS: The granulation duration, healing rate of Days 7 and 14, preoperative time and total preoperative cost in the experiment group was (10.8±2.7) days, 10.1%±2.9%, 22.3%±3.1%, (18.2±2.6) days and (7946±245) yuan RMB versus (16.3±3.9) days, 6.9%±1.9%, 13.4%±2.8%, (27.1±3.3) days and (10,951±285) yuan RMB in the control group respectively. The differences between two groups were statistically significant (all P<0.01). CONCLUSION: As a preoperative therapeutic modality of intractable PU, NPWT and bFGF offer better therapeutic efficacies and lower therapeutic costs as compared with NPWT alone.

[Role of lymphatics in bacterial translocation from intestine in burn rats].

OBJECTIVE: To investigate the role of lymphatics in bacterial translocation from intestine of rats with burn. METHODS: Escherichia coli (E. coli) labeled with chloromethylbenzamidodialkylcarbocyanine (CM-DIL) were prepared. Sixty adult male Wistar rats were randomly divided into scald group and sham injury group according to the envelope method, with 30 rats in each group. Rats in both groups were gavaged with 0.5 mL fluid containing CM-DIL-labeled E. coli. Rats in scald group were inflicted with 30% TBSA deep partial-thickness scald (verified by pathological section) and resuscitated with fluid. Rats in sham injury group were sham injured by bathing in 25 degrees C water for 10 s (verified by pathological section) and also received with fluid infusion. Mesenteric lymph node (MLN), liver, mesenteric lymph fluid (MLF), and liver vein blood (LVB) were harvested at post injury hour (PIH) 2, 24, and 72. Bacteria translocation was detected with fluorescent tracing technique and bacteria culture. The endotoxin content in above-mentioned four kinds of specimens was quantitatively determined with chromogenic substrate limulus amebocyte lysate. The carrying capacity of endotoxin in MLF and LVB was calculated. Data were processed with t test or one-way analysis of variance. RESULTS: (1) Living bacteria were in short-stick form, and they were seen moving in single or in doubles or triples in sample fluid. Dead bacteria were in irregular aggregates. Labeled bacteria in small amount were detected in sham injury group, their number peaked at PIH 24. A large amount of labeled bacteria were detected in scald group at PIH 2, which peaked at PIH 24 and decreased at PIH 72. The largest amount of labeled bacteria were found in MLN in scald group as compared to those in the other samples, and the number peaked at PIH 24 [(5872 +/- 1976) x 10(3) CFU/g], which was obviously higher than that [(216 +/- 110) x 10(3) CFU/g, t = 30.129, P = 0.000] in sham injury group. The number of bacteria decreased at PIH 72, but it was still significantly different from that in sham injury group ( t = 4.323, P = 0.000). The number of bacteria in LVB was the smallest. (2) 29 (24.2%) samples out of the 120 samples in sham injury group were positive for bacteria. 72 (60.0%) samples out of the 120 samples in scald group were positive for bacteria. No alive bacterium was detected at any time point in LVB sample in both group; the other three samples were detected with alive bacteria since PIH 2. There were more alive bacteria detected in MLN and liver as compared with the other two kinds of samples in scald group. The amount of bacteria in MLN, liver, and MLF in scald group were higher than those in sham injury group (with t value respectively 4.353, 4.354, 4.965, P values all equal to 0.000). (3) The endotoxin level in each kind of sample at each time point was obviously higher in scald group than that in sham injury group, and it peaked at PIH 2 in liver and MLF. The difference of endotoxin level among 4 kinds of samples in scald group at PIH 2 was statistically significant ( F = 258.47, P = 0.000), and the endotoxin level was higher in liver, MLN, and MLF. They were obviously higher than those in sham injury group (with t value respectively 43.378, 43.123, 22.423, P values all equal to 0.000). The endotoxin level in MLF was 9 times of that in LVB. (4) The carrying capacity of endotoxin in LVB and MLF at each time point in scald group was higher than that in sham injury group. CONCLUSIONS: CM-DIL marked bacteria can reflect the microbial translocation condition. The lymphatic route is an important pathway for bacteria translocation.

[Effect of survivin antisense oligodeoxynucleotide on proliferation and apoptosis of human malignant melanoma cells].

OBJECTIVE: To investigate the effect of survivin antisense oligodeoxynucleotide (ASODN) on proliferation and apoptosis of human malignant melanoma cells. METHODS: hMMC A375 colonies in log growth phase were collected and divided into control group (C, without transfection), sense chain group [SC, transfected with 600 nmol/L survivin sense oligodeoxynucleotide (ODN)], mismatch chain group (MC, transfected with 600 nmol/L survivin mismatch sense ODN), liposome group (L, treated with liposome), antisense chain group (AC, transfected with survivin ASODN, and subdivided into AC 200, 400, 600 nmol/L subgroups) according to the random number table. Transfection result was observed under inverted fluorescence microscope. Inhibition rate of cell proliferation was calculated after determination of cell viability with MTT method. Cell cycle and apoptosis rate were detected with bi-variable flow cytometry. Expression of survivin protein was determined with Western blot. Activity of caspase-3 was assessed with kinase method. Data were processed with analysis of variance. RESULTS: (1) Cell transfection rates in SC, MC, AC 600 nmol/L groups were all above 80%. (2) Compared with those in SC group [(5.23 +/- 0.25)%], MC group [(5.09 +/- 0.13)%] and L group [(4.70 +/- 0.45)%], inhibition rates of cell proliferation in AC 200, 400, 600 nmol/L groups 24 hours after transfection [(10.30 +/- 0.56)%, (16.69 +/- 0.58)%, (24.67 +/- 0.67)%] were significantly increased (F = 746.91, and P values all below 0.05). As time after transfection went on, proliferation inhibition rate was increased obviously. (3) Apoptosis rate in AC 200, 400, 600 nmol/L groups 24 hours after transfection was respectively (13.5 +/- 1.9)%, (20.1 +/- 1.5)%, (32.1 +/- 2.9)%, which were significantly higher than those in C, SC, MC, and L groups [(6.5 +/- 0.6)%, (5.6 +/- 0.7)%, (6.4 +/- 1.0)%, (6.5 +/- 1.3)%, F = 139.9, P values all below 0.05]. Cells in AC group were blocked in G2/M stage. (4) Compared with those in C group, expression amount of survivin protein decreased, and caspase-3 activity obviously increased (F = 63.1, P values all below 0.05) in AC group. No significant difference in caspase-3 activity between SC, MC, L groups and C group was observed (F = 0.512, P values all above 0.05). CONCLUSIONS: Survivin ASODN can inhibit the proliferation of hMMC A375 in a concentration-time dependent manner, and it induces G2/M stage block and promotes its apoptosis.

[Expression of mast cell tryptase in scar].

OBJECTIVE: To investigate the expression and distribution of mast cell tryptase (MCT) in scar, and to discuss the different MCT gene expression in keloid, hypertrophic scar and normal skin. METHODS: 20 samples of keloid, 20 samples of hypertrophic scar and 20 samples of normal skin were collected. The distribution of MCT was investigated by immunofluorescence histochemistry, and the MCT mRNA expression was detected by Relative Quantification real-time fluorescent PCR. RESULTS: MCT gene was mainly located in the collagen fiber bundles of the scar, especially in the superficial layer of scar. MCT mRNA expression was significantly higher in keloid than that in hypertrophic scar and normal skin (P < 0.01). Averagely, the MCT gene expression in keloid was 2.5 times and 5.4 times of that in hypertrophic scar and normal skin. CONCLUSIONS: MCT gene may play a role in the pathogenesis of scar.

[The significance of TGF-beta expression in scar in adenosine receptor A(2A) knockout mice].

OBJECTIVE: To discuss the mechanism of scar hypertrophy in adenosine receptor A(2A) (A(2A) R) knockout mice. METHODS: Animal models of hypertrophic scar were established in 12 A(2A) R knockout mice and 12 wild-type mice as control. The thickness and the size of transverse section of the hypertrophic scar were observed by H-E staining. The hydroxyproline (HYP) in the scar was measured colorimetrically. The TGF-beta expression was tested by Western blotting method. RESULTS: The hypertrophic scar in wild-type mice was more severe than that in knockout mice. Compared with self-control, the increase of the thickness and the size of transverse section of hypertrophic scar was markedly higher in wild-type group than in the knockout group (P < 0.01). There was significant difference in HYP content between the two groups (P < 0.01). Compared with self-control, the increase of TGF-beta expression in wild-type group was much more than that in knockout group (P < 0.01). CONCLUSIONS: The TGF-beta expression decreases in the A(2A) R knockout mice. The scar hypertrophy is also much less in the A(2A) R knockout mice.

[Application of carbocyanines fluorescent dye for tracing fetal fibroblast transplant: experiment with rats].

OBJECTIVE: To investigate the feasibility of applying carbocyanines fluorescent dye chloromethyl-benzamidodialkyl carbocyanine (CM-Dil) in tracing fetal fibroblast transplant. METHODS: Sixteen-day-gestation fetal rat skin tissue samples were harvested and digested with trypsin to isolate fibroblasts. The fibroblasts proliferated in logarithmic phase and were incubated with CM-Dil for 15 minutes. Flow cytometry was used to calculate the proliferate index (PI) so as to determine the effect of CM-Dil on cell proliferation. Labeled fibroblasts were transplanted to the deep partial thickness burn wounds in the back of allogenic rats. Samples were harvested on 0, 1, 3, 7, 14, and 28 days post burns (DPB) and observed under fluorescence microscope in 6 microm section. RESULTS: The cultured fibroblasts were labeled with CM-Dil within 15 minutes, appearing as red fluorescent discs with bilayer membrane structure. The PI of the labeled fibroblasts was (76.9 +/- 2.8), not significant different from that of the cells not labeled (75.8 +/- 2.0, t = 0.80, P > 0.05). The area with fluorescence markers was small on 1 DPB, began to expand and be distributed in a beaker shape on 3 DPB, and then the bottom of the "beaker" broadened indicating cell proliferation significantly on 7 DPB. Fluorescence signals determined were moderate on 14 DPB, and can be still determined feebly on 28 DPB. CONCLUSION: Proper concentration of CM-Dil shows no cytotoxicity to fetal fibroblasts. CM-Dil is an ideal fluorescent label to fetal fibroblasts for its fairly stable fluorescent tracing and slow quenching in skin tissue within 4 week's duration.

Lymph invasion route of bacteria and endotoxin and CD4+/CD8+ T cells ratio changes of draining lymph node of burn infection wound.

The aim of this study was to determine the lymphatic invasion route of bacteria and endotoxin of burn wounds infected by Pseudomonas aeruginosa and moreover, the effect of P. aeruginosa infection of the burn wound on the draining lymph node and lymph fluid. Male Wistar rats were subjected to unilateral hind limb burn+wound infected by P. aeruginosa (infection limbs group) and contralateral hind limb burn alone (burn limbs group). On hours 6, 24 and 72 after infection, rats were killed, the common iliac lymph nodes (CILN) was collected for the culture of P. aeruginosa. Lymph fluid in the efferent lymph trunk of CILN was collected for the measurement of endotoxin by the Limulus Amebocyte Lysate test. Lymph fluid tumor necrosis factor-alpha (TNF-alpha) concentration was measured by enzyme-linked immunosorbent assay (ELISA). The CD4+/CD8+ T cells ratio of CILN was subjected to flow cytometry analysis. The results showed bacteria invasion incidence, endotoxin and TNF-alpha concentrations were significantly higher in the infection limb group when compared to the burn limb group (P<0.01). The CD4+/CD8+ T cell ratio was significantly lower on post-burn wound infection hours 72 (P<0.05). This study provides evidence that bacteria and endotoxin of burn wound infected by P. aeruginosa invade draining lymph node and lymph fluid. P. aeruginosa infection of the burn wound can increase TNF-alpha level of the draining lymph fluid and decrease CD4+/CD8+ T cells ratio of the draining lymph node.

[Morphological observation of nerve fibers at different periods in full-thickness burn wound].

OBJECTIVE: To observe the change in quantity and morphology of nerve fibers in different periods in granulation tissue in full-thickness burn wound. METHODS: The granulation tissue samples were harvested from 40 patients with full-thickness burn in our unit at 1st, 2nd, 3rd and 4th post burn week (PBW), 10 samples were obtained at each time point. Donor site tissues from 10 burn patients were used as normal control. Immunofluorescent staining technique with anti-neurofilament (NF) monoclonal antibody was employed to examine the expression of nerve fibers in granulation tissue and normal skin. The morphology of nerve fibers was observed with fluorescence microscope and laser scanning confocal microscope. RESULTS: Fluorescence microscopy showed: nerve fibers were short and rare at 1 PBW, the ratio of nerve fibers positive area was (0.14 +/- 0.08)%. Nerve fibers increased slightly and were in single filament without branches, and the positive area ratio of nerve fibers (0.40 +/- 0.09)% was much lower than that of normal control [(0.62 +/- 0.12)%, P < 0.05]. Nerve fibers increased significantly and were arranged like a mesh with more branches and sproutings, and the positive area ratio of nerve fibers was (0.73 +/- 0.16)% at 3 PBW. The quantity of nerve fibers at 4 PBW was similar to that of 3 PBW, and the positive area ratio of nerve fibers was (0.66 +/- 0.13)%. Observations under LSCM: the nerve fibers were short at 1, 2 PBW; was irregular at 3 PBW, among them some were swollen and distorted, and fragmentation and vacuolation were observed. They became aggregated at 4PBW with less branches, similar to that at 3 PBW. The structures of nerve fibers in normal control were intact, without obvious pathological changes. CONCLUSION: The change in quantity and morphology of nerve fibers in burn wound is related to the time of granulation tissue development.

[Expression of tumor necrosis factor related apoptosis inducing ligand and its receptor in thymus during early post-burn stage in rat with severe burns].

OBJECTIVE: To investigate the effect of tumor necrosis factor related apoptosis inducing ligand (TRAIL) and its receptor on apoptosis in thymus during early post-burn stage in rat with severe burns. METHODS: Fifty Wistar rats were randomly divided into sham scald group (SS, n = 10) and burn group (n = 40). The apoptosis in thymus in rats was detected with annexin V/FITC-PI double staining at 4, 12, 24, 48 post-burn hours (PBH). The expression of TRAIL death receptor DR5, DR4 and its decoy receptor DcR1, DcR2 in thymus were detected by RT-PCR and Western blot at above time-points. RESULTS: Compared with that in SS group (6.7 +/- 0.8)%, the apoptosis in the thymus in burn group started to increase at 4 PBH [(17.1 +/- 0.4)%], peaked at 12 PBH [(25.2 +/- 1.1)%], and it was still evidently higher than that in SS group at 48 PBH (P < 0.05). There was no obvious difference in the apoptosis rate in rats in burn group among all the time-points. The expression of DR5 in burn group at each time-points was significantly higher than those in SS group, while that of DcR2 shown an opposite tendency (P < 0.05). The expression of DR4, DcR1 was similar in both groups. CONCLUSION: The marked increase in apoptosis rate in rat thymus at early post-burn stage, and the significant change in the expression of DR5 and DcR2 show that TRAIL pathway may participate in apoptosis.

Changes in cytokine levels and CD4+/CD8+ T cells ratio in draining lymph node of burn wound.

The aim of this study was to determine the changes of cytokine levels in draining lymph fluid and the changes of CD4+/CD8+ T-cells ratio in draining lymph node of burn wound. Male Wistar rats were subjected to unilateral hind limb burn (burn limbs group) and contralateral hind limb without burn (control limbs group). On hours 6, 24, and 72 after burn, rats were killed; lymph fluid in the efferent lymph trunk of the common iliac lymph nodes (CILN) were collected; and lymph fluid Interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-alpha) concentrations were measured by enzyme-linked immunosorbent assay. The CD4+/CD8+ T cells ratio of CILN was submitted to flow cytometry. The results showed TNF-alpha concentrations were significantly greater in the burn limbs group when compared with the control limbs group (P < .05). The IFN-gamma/IL-4 ratio was significantly lower (P < .05). The CD4+/CD8+ T-cell ratio was significantly lower on postburn hours 72 (P < .05). This study provides evidence that the burn wound can increase TNF-alpha levels and decrease IFN-gamma/ IL-4 ratio in the draining lymph fluid and decrease CD4+/CD8+ T cells ratio in the draining lymph node.

[The changes in the tumor necrosis factor alpha, interleukin-6 and interleukin-8 levels in the lymph and of the dynamics of the lymphokines during shock stage of rats with major burns].

OBJECTIVE: To study the dynamic changes in the lymphokines and the changes in tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-8 (IL-8) levels in the lymph during shock stage of rats with major burns. METHODS: Forty-two male adult Wistar rats were randomly divided into burn resuscitation group (A, n = 18), burn non-resuscitation (B, n = 18) and the control (C, n = 6) groups. The TNF-alpha, IL-6 and IL-8 levels in the lymph were determined with radioimmunoassay at 6, 24, 48 postburn hours (PBH). The lymphokines in the mesenteric lymphatic vessels was observed at 6, 24 and 48 PBH with inverted microscopy and digital image processing, and the contraction frequency of the lymphatic was calculated. The lymph was collected by cannulation of the chylous cistern, and its speed of flow was calculated. RESULTS: The lymphatic contents of TNF-alpha and IL-6 in both A and B groups began to increase at 6PBH, reaching the peak values at 24 PBH (TNF-alpha in A and B groups were 1.61 +/- 0.27 ug/L and 1.86 +/- 0.34 ug/L, respectively; IL-6 in A and B groups were 398 +/- 67 ng/L and 572 +/- 97 ng/L, respectively), and they were significantly higher than those in C group at each time points (P < 0.01), meanwhile there was also obvious difference in them between A and B groups (P < 0.01). The lymphatic contents of IL-8 in A and B groups began to increase at 24 PBH, and continued to increase till 48PBH (540.29 +/- 0.32 ng/L in A group, 863.48 +/- 105.16 ng/L in B group), which were evidently higher than those in C group (P < 0.01). There was significant difference in IL-8 contents between A and B groups (P < 0.01). The contraction frequency of the mesenteric lymphatic vessels in A and B groups were decreased, especially so at 24 PBH (P < 0.01). The speed of lymphatic flow in A and B groups was increased at each time points (P < 0.01). The central chylous vessels in the villi of the small intestine were extremely dilated as seen under microscope. CONCLUSION: After burn injury, the lymphatic vessels dilated, with its motility decreased and speed of flow increased, and the contents of TNF-alpha, IL-6 and IL-8 in lymph were increased during the shock stage of burn rats. Fluid resuscitation could improve the lymph circulation.