MXene/Carbon Nanotube Hybrids: Synthesis, Structures, Properties, and Applications.

Since the successful preparation of few-layer transition metal carbides from three-dimensional MAX phases in 2011, MXenes (known as a family of layered transition metal carbides, nitrides, and carbonitrides) have been intensively studied. Though MXenes have been adopted as active materials in many applications, issues including aggregation and restacking are likely to hamper their potential applications. In order to address these prevailing challenges, the concept of MXene/carbon nanotube (CNT) hybrids was proposed initially in 2015, where CNTs were incorporated as the spacers and conductive additives. Ever since, MXene/CNT hybrids with different architectures have been synthesized by a number of methods and applied in numerous fields. Herein, after the discussion about general synthesis approaches, architectures, and properties of the hybrids, this Review summarized the recent advances in the application of MXene/CNT hybrids in energy storage devices, sensors, electrocatalysis, electromagnetic interference shielding, and water treatment, in which the function of individual components was clarified. In the end, the current research trend in this field were discussed and several technical issues were highlighted along with some suggestions on future research directions.

HS-SPME GC-MS characterization of volatiles in processed walnuts and their oxidative stability.

Processed walnuts including hot air-dried and roasted walnuts were prepared. Volatiles in raw and processed walnuts were analyzed using head-space solid phase microextraction combined with gas chromatography and mass spectrometry. Oxidative stability of hot air-dried walnuts in different antioxidants, with or without vacuum package was studied to find a proper package for oxidation stability of hot air-dried walnuts. The results showed that there were 14 volatiles in raw walnuts, 28 in hot air-dried walnuts and 38 in roasted walnuts. The changes of oil quality indices, total phenols, malondialdehyde and free radical scavenging activities during storage at 60 °C showed that the oil oxidation increased with storage time. The addition of antioxidants and vacuum package could slow down the oxidation. Vacuum aluminum foil package (14 × 20 cm) can delay the oil oxidation and extend the shelf life to ~ 230 days of hot air-dried walnuts at 20 °C. With added antioxidant this was extended to ~ 257 days.

Effect of rosuvastatin on OX40L and PPAR-γ expression in human umbilical vein endothelial cells and atherosclerotic cerebral infarction patients.

Atherosclerotic cerebral infarction (ACI) is characterized by extremely high fatality and disability rate. Recent studies indicate that co-stimulatory signal of tumor necrosis factor superfamily OX40/OX40L contributes to the atherosclerosis effect in ACI patients. However, it remains unclear the mechanism underlying the anti-atherosclerosis process. So this study aims to investigate the effects of rosuvastatin on the expression of OX40L, peroxisome proliferator-activated receptors gamma (PPAR-γ) in human umbilical vein endothelial cells (HUVEC), and human peripheral blood lymphocytes. Different concentration of rosuvastatin and oxidized low-density lipoprotein (OX-LDL) co-intervene HUVEC to observe the expression of OX40L and PPAR-γ using real-time quantitative RT-PCR (Q-RTPCR) and Western-blot. Furthermore, we examined the level changes of plasmic sOX40L and hs-CRP in acute atherosclerotic cerebral infarction patients. The results demonstrated that concentration-dependent and time-dependent OX-LDL remarkably stimulate the expression of OX40L and inhibit the expression of PPAR-γ in vitro. But concentration-dependent rosuvastatin can reverse the impact of OX-LDL, suggesting that rosuvastatin can prevent the expression of OX40L, and the process may be associated with mevalonate pathway. In vivo, acute atherosclerotic cerebral infarction patients taking 20 mg rosuvastatin exhibited significantly reduced expression of OX40L in peripheral blood lymphocyte, sOX40L in blood plasma, and hs-CRP compared with before treatment. Our studies identified rosuvastatin as an effective medicine in controlling atherosclerosis process in ACI by inhibiting OX40L and stimulating PPAR-γ expression.

[Effects of panthenol-glutamine on intestine of rats with burn injury and its dose-effect relationship].

OBJECTIVE: To study the effects of the panthenol-glutamine on intestinal damage and motor function of intestine in rats with burn injury as well as its dose-effect relationship. METHODS: (1) Experiment 1. Ninety SD rats were divided into groups A-I according to the random number table, with 10 rats in each group. Rats in groups A-I were inflicted with 30% TBSA full-thickness burn and fed by gavage with panthenol and glutamine at post injury hour (PIH) 4, in the whole dosage of 1.00 and 4, 0.50 and 4, 0.25 and 4, 1.00 and 2, 0.50 and 2, 0.25 and 2, 1.00 and 1, 0.50 and 1, 0.25 and 1 g·kg(-1)·d(-1). The feeding was carried out twice a day to achieve the total dosage in 7 days. On drug withdrawal day, blood and intestinal tissue were harvested to detect the intestinal propulsion index, diamine oxidase (DAO) activity in serum, and the content of acetylcholine and intestinal mucosa protein. The best proportion of panthenol and glutamine was screened. (2) Experiment 2. Seventy SD rats were divided into normal control (NC), burn (B), burn+panthenol (B+P), burn+glutamine (B+G), and burn+low, moderate, or high dose of panthenol-glutamine (B+LPG, B+MPG, B+HPG) groups according to the random number table, with 10 rats in each group. Rats in the latter 6 groups were inflicted with 30% TBSA full-thickness burn. Rats in the latter 5 groups were fed by gavage with panthenol and (or) glutamine at PIH 4. Rats in group B+P were fed with panthenol for 1 g·kg(-1)·d(-1), rats in group B+G with glutamine for 4 g·kg(-1)·d(-1), rats in groups B+LPG, B+MPG, and B+HPG with panthenol and glutamine in the dosage of 0.50 and 2, 1.00 and 4, 2.00 and 8 g·kg(-1)·d(-1). The feeding was carried out twice a day to achieve the total dosage for 7 days. The indexes and time point for observation were the same as those of experiment 1. Meanwhile, the pathological change in intestine was observed. The same process was carried out in the rats of group NC. Data were processed with factorial designed analysis of variance (ANOVA), one-way ANOVA and Fisher's exact probability test. LSD was applied for paired comparison. RESULTS: (1) The values of intestinal propulsion index and intestinal mucosa protein content in groups A and B were close (with P values all above 0.05), and were significantly higher than those of the other 7 groups (with P values all below 0.01). Content of acetylcholine in group A was significantly higher than that of the other 8 groups (with P values all below 0.01). DAO activity in groups A, D, and E was close in value (with P values all above 0.05), and all of the values were significantly lower than those of the other 6 groups (with P values all below 0.01). The best proportion of panthenol and glutamine was 1.00 and 4 g·kg(-1)·d(-1). (2) Compared with those of group NC, the intestinal propulsion index, the contents of acetylcholine and intestinal mucosa protein were decreased significantly, while the DAO activity obviously increased in group B (with P values all below 0.01); the intestinal propulsion index was decreased significantly in group B+P (P < 0.01); the intestinal propulsion index and content of acetylcholine were decreased significantly in group B+G (with P values all below 0.01); the intestinal propulsion index was decreased significantly in group B+LPG (P < 0.01); no obvious change was observed in groups B+MPG and B+HPG (with P values all above 0.05). Compared with those of group B [0.50 ± 0.07, (69 ± 10) µg/mL, (26 ± 11) µg/g, (0.672 ± 0.145) U/mL], the contents of acetylcholine and intestinal mucosa protein were increased significantly, DAO activity decreased significantly in group B+P (with P values all below 0.01); the contents of intestinal mucosa protein was increased significantly, DAO activity decreased significantly in group B+G (with P values all below 0.01); the contents of acetylcholine and intestinal mucosa protein were increased significantly in group B+LPG (with P values all below 0.01); the intestinal propulsion index, the contents of acetylcholine and intestinal mucosa protein were increased significantly, while the DAO activity obviously decreased in groups B+MPG and B+HPG [0.66 ± 0.07, 0.68 ± 0.05; (163 ± 24), (168 ± 15) µg/mL; (57 ± 7), (57 ± 7) µg/g; (0.203 ± 0.070), (0.193 ± 0.068) U/mL, with P values all below 0.01]. The levels of the four indexes in groups B+MPG and B+HPG were close or the same in values (with P values all above 0.05). Compared with those of group B, the numbers of rats with irregularly arranged villi in group B+P were decreased significantly (P < 0.05); the numbers of rats with villi decreased in height, irregularly arranged villi, and neutrophil infiltration in group B+G were decreased significantly (with P values all below 0.05); the numbers of rats with villi decreased in height, irregularly arranged villi, degeneration and necrosis of cells, and neutrophil infiltration in group B+LPG were decreased significantly (with P values all below 0.05); the numbers of rats with villi decreased in height and number, irregularly arranged villi, degeneration and necrosis of cells, and neutrophil infiltration in groups B+MPG and B+HPG were decreased significantly (with P values all below 0.05). There was no statistically significant difference between group B+HPG and group B+MPG for the former mentioned five indexes (with P values all above 0.05). CONCLUSIONS: Combined application of panthenol and glutamine can obviously reduce intestinal mucosa damage and promote gastrointestinal motility of rats with burn injury, and they show curative effect superior to exclusive use of either of the two drugs. The best proportion of panthenol and glutamine is 1.00 and 4 g·kg(-1)·d(-1).

[Relationship between activation of Rho kinase signal pathway and permeability of hypoxic vascular endothelial cells].

OBJECTIVE: To investigate the relationship between activation of Rho kinase (ROCK) signal pathway and permeability of hypoxic vascular endothelial cells. METHODS: (1) Human vascular endothelial cell line VE cells were planted onto 6-well plates Transwell and divided into control group (without hypoxia treatment) and hypoxia for 1, 2, 3, 6, 12 h groups (exposed to 1%O2, 5%CO2, and 94%N2 for corresponding time) according to the random number table, with 5 wells in each group. The expression levels of ROCKI, ROCKII, myosin light chain phosphatase target subunit 1 (MYPT1) and phosphorylated MYPT1 (p-MYPT1), myosin light chain (MLC), p-MLC in cells were detected by Western blotting. The ratios of p-MYPT1/MYPT1 and p-MLC/MLC were calculated. (2) VE cells were planted onto 24-well plates Transwell, and the monolayer cells were divided into control group (without hypoxia treatment) and hypoxia for 6 h group (exposed to 1% O(2), 5% CO(2), and 94% N(2) for 6 h) according to the random number table, with 5 wells in each group. Permeability of monolayer cells was determined by fluorescence spectrophotometer. Data were processed with one-way analysis of variance or t test, and Newman-Keuls method was used in paired comparison among groups. RESULTS: (1) ROCKI protein expression in control and hypoxia for 1, 2, 3, 6, 12 h groups was obviously 0.63 ± 0.14 and 0.36 ± 0.08, 1.25 ± 0.21, 1.98 ± 0.16, 1.49 ± 0.38, 0.79 ± 0.24 (F = 36.52, P < 0.01). ROCKI protein expression in hypoxia for 2, 3, 6 h groups were obviously higher than that in control group (with P values all below 0.01). (2) There was significant statistical difference among all groups in ROCKII protein expression (F = 17.84, P < 0.01). ROCKII protein expression in hypoxia for 2 h group (1.33 ± 0.17) was significantly higher than that in control group (1.05 ± 0.04, P < 0.01). (3) p-MYPT1/MYPT1 ratio in control and hypoxia for 1, 2, 3, 6, 12 h groups was respectively 0.62 ± 0.13 and 0.62 ± 0.11, 0.65 ± 0.10, 1.06 ± 0.23, 1.37 ± 0.16, 1.91 ± 0.32 (F = 37.41, P < 0.01). p-MYPT1/MYPT1 ratio in hypoxia for 3, 6, 12 h groups were obviously higher than that in control group (with P values all below 0.01). (4) p-MLC/MLC ratio in control and hypoxia for 1, 2, 3, 6, 12 h groups was respectively 0.72 ± 0.19 and 0.83 ± 0.17, 0.91 ± 0.15, 1.39 ± 0.16, 2.02 ± 0.15, 0.90 ± 0.25 (F = 36.92, P < 0.01). p-MLC/MLC ratio in hypoxia for 3, 6 h groups were obviously higher than that in control group (with P values all below 0.01). (5) Permeability of VE monolayer in hypoxia for 6 h group (36.1 ± 8.0) was obviously higher than that in control group (9.1 ± 2.1, t = 7.30, P < 0.01). CONCLUSIONS: Activation of ROCK signal pathway may be involved in the pathogenesis of vascular endothelial cell hyperpermeability induced by hypoxia.

[An experimental study on intestinal epithelial barrier dysfunction induced by interferon-gamma and tumor necrosis factor-alpha].

OBJECTIVE: To investigate the effect of combination of interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) on intestinal epithelial barrier function. METHODS: The Caco-2 monolayers were cultured in DMEM nutrient solution, and then they were inoculated in 24-well or 6-well plate with Transwell inserts.They were divided into control group (ordinary treatment), IFN-γ group (with addition of 10 ng/mL IFN-γ), TNF-α group (with addition of 10 ng/mL TNF-α), and IFN-γ plus TNF-α group (with addition of 10 ng/mL TNF-α and 10 ng/mL IFN-γ). Monolayers inoculated in 24-well plate were collected for determination of transepithelial electrical resistance (TER) with an ohmmeter at post treatment hour (PTH) 0, 6, 12, 24, 36, and 48, the permeability of monolayers with fluorescein isothiocyanate-labeled dextran (FITC-dextran) tracer method at PTH 48, the distribution and morphological change of tight junction occludin with immunofluorescence assay at PTH 48. Monolayers inoculated in 6-well plate were collected for determination of protein expression of occludin, myosin light chain kinase (MLCK), and phosphorylated MLC (pMLC) with Western blot at PTH 24. Data were processed with one-way analysis of variance and t test. RESULTS: (1) There was no obvious difference in TER in control group at each time point (F = 0.86, P > 0.05). TER in IFN-γ group and TNF-α group were gradually decreased during PTH 6-48, but showed no statistical difference as compared with that at PTH 0 (with F value respectively 1.69, 2.47, P values all above 0.05). TER in IFN-γ plus TNF-α group was significantly decreased from PTH 24 as compared with that at PTH 0 (t = 4.97, P < 0.05) and that in each of the other three groups (F = 11.54, P < 0.05). (2) The permeability of monolayers in IFN-γ plus TNF-α group [(1197 ± 215)pmol] was significantly higher than that in control group, IFN-γ group, and TNF-α group [(303 ± 93), (328 ± 76), (797 ± 177) pmol, with t value respectively 4.8, 5.0, 6.9, P values all below 0.01]. (3) There was no statistical difference in occludin expression at PTH 24 among four groups (F = 0.26, P > 0.05). The occludin in control group at PTH 48 was regular in arrangement, while that in IFN-γ and TNF-α groups was irregular in arrangement. The arrangement of occludin in IFN-γ plus TNF-α group at PTH 48 was interrupted, with obvious redistribution in cytoplasm. (4) The protein expression of pMLC in IFN-γ plus TNF-α group (0.95 ± 0.05) was significantly higher than that in control group, IFN-γ group, or TNF-α group (0.57 ± 0.12, 0.56 ± 0.07, 0.59 ± 0.10, respectively, F = 17.97, P < 0.01). The protein expression of MLCK in IFN-γ plus TNF-α group (1.57 ± 0.36) was also significantly higher than that in control, IFN-γ, TNF-α groups (0.85 ± 0.18, 1.04 ± 0.23, 1.00 ± 0.07, respectively, F = 9.05, P < 0.05). CONCLUSIONS: Combination of IFN-γ and TNF-α can induce intestinal epithelial barrier dysfunction by up-regulating MLCK protein expression and promoting MLC phosphorylation.

[Research on intestinal tight junction barrier dysfunction should be emphasized in burn injury].

Severe burn injury is often accompanied by intestinal epithelial tight junction barrier dysfunction, which is believed to be closely associated with postburn shock, inflammation, hypermetabolism, infection, organ dysfunction etc. Recent studies have documented the critical role of tight junction-associated protein regulation in intestinal epithelial barrier dysfunction induced by severe burn injury. Myosin light chain (MLC) phosphorylation regulated by both myosin light chain kinase, which can phosphorylate MLC directly, and Rho-associated kinase, which can inhibit MLC phosphatase and then induce MLC phosphorylation indirectly, play a critical role in intestinal epithelial tight junction barrier dysfunction which occurs in severe burn injury. Recent advances have provided new insights into the mechanisms and the therapeutic strategies of intestinal epithelial tight junction barrier dysfunction following severe burn injury.

[Effect of hypoxia-inducible factor-1alpha inhibition caused by RNA interference on permeability of hypoxic endothelial cells].

OBJECTIVE: To study the effect of hypoxia-inducible factor-1alpha (HIF-1alpha) inhibition caused by RNA interference on permeability of hypoxic vascular endothelial (VE) cells. METHODS: Plasmid pcDNA6.2-GW/EmGFP-miR was applied to construct the RNA interference expression vector targeted to human HIF-1alpha gene. VE cells were divided into normal control group (NC), hypoxia group (H, cells were treated for hypoxia in mixed gas with 1% O(2) for 6 hours), transfection group (T), and transfection hypoxia group (TH, transfected with vector and treated with hypoxia). Expression of HIF-1alpha mRNA in NC and T groups were determined with RT-PCR. Expression of HIF-1alpha protein in each group was determined with Western blot. The permeability of VE cell monolayer was detected by fluorospectrophotometer. Another sample of VE cells were divided into dimethyloxallyl glycine (DMOG) group, transfected with DMOG group (TD), normal control group (NC), and transfection group (T), with 1 mmol/L DMOG (HIF-1alpha specific derivant) replacing hypoxia treatment. The expression of HIF-1alpha protein in each group was determined with Western blot. All data were recorded as density value ratio except for permeability data, which was recorded as fluorescence intensity value. Data were processed with t test (pairwise comparison among groups). RESULTS: The relative content of HIF-1alpha mRNA of cells in NC group (0.765 +/- 0.069) was significantly higher than that of cells in T group (0.093 +/- 0.007, t = 16.696, P < 0.05). Content of HIF-1alpha protein of cells in TH group (0.591 +/- 0.029) was significantly lower than that of cells in H group (2.612 +/- 0.259, t = 13.415, P < 0.05). Content of HIF-1alpha protein of cells in TD group (0.566 +/- 0.008) was significantly lower than that of cells in DMOG group (3.243 +/- 0.551, t = 6.975, P < 0.05). The permeability of cell monolayer in H group (41.6 +/- 11.1) was significantly higher than that of cell monolayer in NC group (9.4 +/- 1.5, t = 6.238, P < 0.05). The permeability of cell monolayer in TH group (13.3 +/- 4.5) was markedly lower than that of cell monolayer in H group (t = 5.430, P < 0.05). CONCLUSIONS: The expression of HIF-1alpha gene in vascular endothelial cells is effectively inhibited by specific RNA interference, which significantly prevents the hypoxia-induced increase in vascular endothelial cell permeability.

Helicobacter pylori-induced Th17 responses modulate Th1 cell responses, benefit bacterial growth, and contribute to pathology in mice.

CD4(+) T cell responses are critical for the pathogenesis of Helicobacter pylori infection. The present study evaluated the role of the Th17 subset in H. pylori infection. H. pylori infection induced significant expression of IL-17 and IFN-gamma in mouse gastric tissue. IL-23 and IL-12 were increased in the gastric tissue and in H. pylori-stimulated macrophages. Cell responses were examined by intracellular staining for IFN-gamma, IL-4, and IL-17. Mice infected with H. pylori developed a mixed Th17/Th1 response; Th17 responses preceded Th1 responses. Treatment of mice with an anti-IL-17 Ab but not a control Ab significantly reduced the H. pylori burden and inflammation in the stomach. H. pylori colonization and gastric inflammation were also lower in IL-17(-/-) mice. Furthermore, administration of recombinant adenovirus encoding mouse IL-17 increased both H. pylori load and inflammation. Further analysis showed that the Th1 cell responses to H. pylori were downregulated when IL-17 is deficient. These results together suggest that H. pylori infection induces a mixed Th17/Th1 cell response and the Th17/IL-17 pathway modulates Th1 cell responses and contributes to pathology.

[The role of myosin light chain kinase in intestinal epithelial barrier dysfunction due to hypoxia].

OBJECTIVE: To study the role of myosin light chain kinase (MLCK) in intestinal epithelial barrier dysfunction after hypoxia. METHODS: The Caco-2 monolayers developed with Transwell inserts were exposed to hypoxia for 0 h (NC group), 2, 6, 8, 12 and 24 h (H group), and 6 h hypoxic specimens were treated with 100 mol/L ML-9 (T group). The transepithelial electrical resistance (TER) of monolayers was measured with an ohmmeter. The tight junction protein ZO-1 of monolayers was analyzed by immunofluorescence assay. The protein expressions of phosphorylated myosin light chain (p-MLC) and MLCK were detected by Western blotting. RESULTS: The TER of monolayers in H group at 6, 8, 12 and 24 h was 422 +/- 17, 427 +/- 27, 403 +/- 40 and 426 +/- 22 ohms respectively, which was significantly lower than that of NC group (451 +/- 27 ohms, P < 0.05). The TER of monolayers in T group was 558 +/- 110 ohms, which was significantly higher than that in H group at each time point ( P < 0.01). The ZO-1 of monolayers in H group at 6 h was irregular in arrangement, with interruptions and rugae, and sawtooth. These abnormalities were ameliorated in T group (regular in arrangement, with little or without ruga and sawtooth). The protein expressions of p-MLC and MLCK in H group at each time point were higher than those in NC group. CONCLUSIONS: Intestinal epithelial barrier dysfunction after hypoxia can be mediated by MLCK.

[Role of corticotropin releasing factor receptor 2 antisense oligodeoxynucleotide of hypothalamus in hypermetabolism in rats with severe burn].

OBJECTIVE: To observe the role of corticotropin releasing factor receptor 2 antisense oligodeoxynucleotide (CRFR2ASO) of hypothalamus in hypermetabolism in rats with severe burn. METHODS: Stainless-steel cannula were implanted into the 3rd ventricle. According to different medicine delivered into the 3rd ventricle, 30 SD rats with 30% TBSA full-thickness burn were divided randomly into burn control group (BC, with injection of 3 microL saline), CRFR1ODN group (with injection of CRFR1ODN 10 microg), CRFR1ASO group (with injection of CRFR1ASO 10 microg), CRFR2ODN group(with injection of CRFR2ODN 10 microg), CRFR2ASO group (with injection of CRFR2ASO 10 microg), with 6 rats in each group. Another 6 rats served as normal control (NC) and they received isotonic saline 3 microL instead. Different medicines were respectively delivered into respective group on 5, 6 post injury day (PID), then 3 microL gentian violet was introduced on 7 PID. Resting energy expenditure (REE) value and the expression level of hypothalamus CRFR2mRNA and CRFR2 protein were determined. RESULTS: REE value in BC, CRFR1ODN, CRFR1ASO, CRFR2ODN, CRFR2ASO groups was 11 840 +/- 987, 11 133 +/- 1100, 10 733 +/- 1338, 11 123 +/- 1321, 7563 +/- 890 kJx(m2)(-1)xd(-1), respectively, which were obviously higher than that in BC group [6641 +/- 526 kJx(m2)(-1)xd(-1), P < 0.05]. REE value in CRFR2ASO group was obviously lower than that in CRFR2ODN group (P < 0.01). The expression level of hypothalamus CRFR2 mRNA and its protein in BC group were increased after burn, which were obviously lower in CRFR2ASO group than NC group (P < 0.01). CONCLUSION: Central application of CRFR2ASO can downregulate the expression level of hypothalamus CRFR2 mRNA and its protein, and reduce hypermetabolism. Hypothalamus CRFR2 may mediate hypermetabolism in burn rats.

[Effect of hypoxia on hypoxia inducible factor 1alpha (HIF-1alpha) activation in intestinal epithelial cells].

OBJECTIVE: To investigate the effect of hypoxia on HIF-1alpha activation in intestinal epithelial cells. METHODS: Intestinal epithelial cells were randomly divided into normal control group, hypoxia group and hypoxia plus oligomycin group (oligomycin group). In hypoxia group, the cells were exposed to hypoxia for 1, 2, 6, 12 and 24 h. In oligomycin group, the cells were treated with oligomycin in concentration of 5, 10, 20 and 40 microg/mL for 1 h prior to 6-hour hypoxic exposure. HIF-1alpha protein expression was assayed by western blot method. Nuclear translocation of HIF-1alpha was detected by immunofluorescence analysis. RESULTS: Compared with that in control group (0.08 +/- 0.07), HIF-1alpha protein expression in hypoxia group increased significantly at 1 h (0.52 +/- 0.30, P < 0.05), and reached the peak value (2.37 +/- 1.08, P < 0.05) at 6 h. Nuclear translocation of HIF-1alpha was also induced by hypoxia. HIF-1alpha protein expression in oligomycin group in the concentration of 5, 10, 20 and 40 microg/mL of oligomycin was 1.62 +/- 0.96, 1.48 +/- 0.56, 1.08 +/- 0.36 and 0.58 +/- 0.11 respectively, which was significantly lower than that only after exposure to hypoxia for 6 h (2.67 +/- 1.38, P < 0.05). The nuclear translocation of HIF-1alpha induced by hypoxia was also obviously inhibited by oligomycin pretreatment. CONCLUSION: Oligomycin, a specific inhibitor of respiratory chain, inhibits HIF-1alpha activation, which suggests that mitochondria respiratory chain may play an important role in aforementioned process.

[The protective effect of recombinant glucagons like peptide-2 on intestinal mucosa of burn rats].

OBJECTIVE: To investigate the protective effect of recombinant glucagons like peptide-2 (GLP-2) on intestinal mucosa of rats with severe burns. METHODS: SD rats of either sex were randomly divided into 4 groups: normal control (N, n = 6), burn control group (C, n = 6), recombinant GLP-2 group (Gr, n = 6, with subcutaneous injection of 100 nmol x kg(-1) x d(-1) recombinant GLP-2 at 4 post-burn hours (PBH) and synthesized GLP-2 group (G, n = 6, with subcutaneous injection of 100 nmol x kg(-1) x d(-1) synthesized GLP-2 at 4 PBH). Except the normal control group, all animals in the other groups received a 30% TBSA third degree burns, the rats were sacrificed on 7 postburn days (PBD) and the following indexes were determined: pathological examination of intestinal mucosa, mucosa permeability of intestinal mucosa, the ratio of mucosa wet weight and bowel mass or carcase weight, and the protein content of intestinal mucosa. RESULTS: Compared with that in burn group [(0.350 +/- 0.040) mg/ml], the mucosa permeability significantly decreased in Gr (0.250 +/- 0.026) mg/ml and G (0.243 +/- 0.008) mg/ml groups, while the ratio of mucosa wet weight and carcase weight, the protein content of intestinal mucosa were significantly increased. In addition, the content of intestinal mucosal protein in Gr group [(57.9 +/- 2.8) mg/g wet weight] was higher than that in G group [(48.9 +/- 4.1) mg/g wet weight]. In contrast to normal controls, the villi of intestinal mucosa in rats on 7 PBD were obviously shortened and exfoliated, with deranged disposition and thinned basal membrane. No obvious difference of the injury was observed between Gr and G groups, and the injury was milder when compared with burn group. CONCLUSION: Recombinant GLP-2, as well as synthesized GLP-2, exhibits obvious protective effect on intestinal mucosa in alleviating injury to intestinal mucosa in burn rats.

[Transfection and identification of the cloned strain that stably expressing glucagon like peptide-2 receptor in CaCO2 cell lines].

OBJECTIVE: To establish Caco2 cell line with stable expression of glucagon like peptide-2 receptor( GLP-2R) , in order to establish an in vitro model for the study of protective mechanism of GLP-2 of the intestinal tract. METHODS: The GLP-2R/pcDNA3. 1 ( + ) plasmid was verified by restriction endonuclease and sequencing , and then it was transfected into Caco2 cells with lipofectamine. After G418 selection, the clones with stable expression of GLP-2R were obtained by limited dilution cloning and expanding. The mRNA and protein expression of GLP-2R in normal human intestine, Caco2 cells, HER293, VE cells, as well as in transfected Caco2 cells were determined with RT-PCR and Western blot. RESULTS: The sequence of GLP-2R/pcDNA 3. 1 plasmid was correct. No expression of GLP-2R mRNA and protein was found in HER293 and VE cells, but weak expression were found in Caco2 cells, and strong expression was found in normal human intestines. The expression of GLP-2R mRNA and protein expression in Caco2/GLP-2R ( + ) cells were obviously increased after transfection. CONCLUSION: GLP-2R has special distribution. The expression of GLP-2R is weak in normal Caco2 cells. The establishment of Caco2/GLP-2R ( + ) cellular model is beneficial for the further research of the mechanism of action of GLP-2.

[Experience in resection of hilar cholangiocarcinoma: a report of 54 cases].

OBJECTIVE: To summarize the experience in ameliorating curative resection rate and major postoperative complication rate for treatment of hilar cholangiocarcinoma. METHODS: Respective analysis was made on the clinical data of 54 consecutive cases who underwent resection of hilar cholangiocarcinoma from Jan. 1998 to Dec. 2004. RESULTS: In this group 54 cases received tumor resection with a resection rate of 63.5%. Combined partial hepatectomy was performed in 14 patients, while combined pancreaticoduodenectomy (Whipple) in 3 patients, and combined resection of portal vein in 2 patients and combined resection of hepatic artery in 2 patients. Thirty patients had curative resection. The curative resection rate was greatly increased from 27.0% (before 2001) to 41.7% (after 2001) in this group with well controlled perioperative mortality and postoperative complications rate (e.g. hepatic failure and major infection). The gross 1-, 2-, and 3-year survival rates for the whole group were 67.4%, 28.1% and 13.5% respectively. The 1-, 2-, and 3-year survival rates for curative resection were 87%, 36% and 24% respectively. The 1-, 2-year survival rates for palliative resection were 42% and 18%. CONCLUSIONS: Enhanced surgical technique resulted in better clinical outcomes.

[An experimental study on the relationship between the extracellular matrix and apoptosis of intestinal epithelium after burn injury].

OBJECTIVE: To explore the relationship between the extracellular matrix and apoptosis of intestinal epithelium after burn injury. METHODS: Thirty Wistar rats were employed in the study and were randomly divided into normal control (C) and 6 PBH (postburn hour), 12 PBH, 1 PBD (postburn day), 3 PBD and 5 PBD group with 5 rats in each group. The rats in burn groups were sacrificed at 0, 6 and 12 PBHs and 1, 3 and 5 PBDs. The apoptotic cell count and the caspases-3 activity of intestinal mucosal epithelium, and the extracellular matrix component laminin and type IV collagen were determined and their correlation was analyzed. RESULTS: The apoptotic cell count and the caspases-3 activity of intestinal mucosal epithelium in burn groups were obviously higher than those in C group (P < 0.05 or 0.01), while the intestinal mucosal contents of laminin and type IV collagen in burned groups were much lower than those in C group (P < 0.05 or 0.01). By linear correlative analysis, it was shown that the changes in the intestinal mucosal contents of laminin and type IV collagen in burned groups were negatively correlated with the change in apoptotic cell count (r = -0.575, -0.613, P < 0.05). CONCLUSION: Intestinal epithelial apoptosis was enhanced after burn injury, and it was correlated with the change in the components of the extracellular matrix.

[Influence of glucagon-like peptide-2 on the proliferation of the intestinal mucosal cells in scalded rats].

OBJECTIVE: To explore the influence of glucagon-like peptide-2 (GLP-2) on the proliferation of the intestinal mucosal cells in scalded rats. METHODS: Fifty-five Wistar rats were employed in the study and were randomly divided into normal control (C), simple scald (S) and scald with GLP-2 treatment (G) groups. The rats in G group received GLP-2 introperitoneally in a dose of 200 micro g/kg two times a day. The rats in S and G groups were sacrificed at 6 postburn hours (PBHs), 12 PBHs, 1 postburn day (PBD1), PBD3 and PBD5 and the rats in C group were also sacrificed. Plasma diamine oxidase (DAO) activity, cell cycle protein cyclin D expression and the proliferating cell nuclear antigen (PCNA) in all groups were determined. And the histological change in the intestinal mucosal tissue was observed simultaneously. with all the above determinations. RESULTS: Compared with those in C group, the PCNA expression at 6 and 12 PBHs in S group was enhanced slightly and weakened at PBD1, reaching the lowest level at PBD3 and it was still lower than that in C group at PBD5. Changes in PCNA in G group were similar to that in S group, except that the expression at PBD3 and PBD5 was stronger than that in S group. The intestinal mucosal cyclin D protein expression was increased at 6 and 12 PBHs in S group, but decreased by 40% before injury at PBD1. Nevertheless, the cyclin D protein expression in G group was much higher than that in S group at PBD1, PBD3 and PBD5. The plasma DAO activity increased significantly in rats after burn injury. But the activity decreased obviously after GLP-2 treatment for 5 days (P < 0.01). It was observed histologically in G group that the lining of Exogenous intestinal villi was regular and well arranged without evident epithelial exfoliation. CONCLUSION: Exogenous GLP-2 might ameliorate intestinal mucosal injury in scalded rats, and promotion of the expression of PCNA and cyclin D, resulting in proliferation of injured intestinal mucosal cells, might be the underlying mechanisms.