1.Construction of recombinant retroviral vector of short interfering RNAs specific for macrophage migration inhibitory factor (MIF) and establishment of stable HeLa cell line with a persistent knockdown of MIF
Bo DAI ; Dingzhang XIAO ; Xiyong YU
Chinese Journal of Pathophysiology 2000;0(11):-
AIM:To construct recombinant retroviral vector of short interfering RNAs (siRNA) specific for macrophage migration inhibitory factor (MIF) and to establish the stable knockdown of MIF cell line of mammalian cells by transfecting the recombinant retroviral vectors. METHODS: We synthesized oligo-nucleotides for MIF in vitro, and cloned them into retroviral vector pSuper.retro. Subsequently the plasmids were sequenced and digested to identify the construction of the recombinant retroviral vectors. The vectors RNAi were transfected into packing cell line PHOENIX, which was selected by puromycin later. HeLa cell line was infected by the virus supernatant of stable PHOENIX cell lines, and the stable HeLa cell line showed significantly to silence MIF was established by selecting with puromycin. We also compare the characters of HeLa-pSuper-mock to HeLa-pSuper-MIF cells by using migration assay, adhesion assay, soft agar assay and FACS analysis of the cell-cycle progression. RESULTS: The recombinant retroviral vectors were constructed successfully. The HeLa cell line infected by the supernatant containing the retrovirus of package PHOENIX cells was persistent knockdown of MIF confirmed by Western blotting. Knockdown of MIF in HeLa cells inhibited the migration and adhesion, and decreased the clone formation. FACS analysis revealed that knockdown of MIF arrested HeLa cells in G0/G1 phase. CONCLUSION: We establish the stable HeLa cell line with a persistent knockdown of MIF. Our current studies reveal that MIF is necessary for HeLa cell migration and anchorage-independent growth.
2.Clinical analysis of the peri-operative complications following percutaneous transhepatic biliary drainage or stent implantation.
Ping YU ; Ding-ke DAI ; Xiao-jun QIAN
Chinese Journal of Oncology 2009;31(12):923-924
Adult
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Aged
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Aged, 80 and over
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Biliary Tract Neoplasms
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complications
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Cholangitis
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etiology
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Cholestasis
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etiology
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therapy
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Drainage
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adverse effects
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Female
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Hepatic Encephalopathy
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etiology
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Humans
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Intraoperative Period
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Jaundice, Obstructive
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etiology
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therapy
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Liver Neoplasms
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complications
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Male
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Middle Aged
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Pancreatitis
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etiology
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Stents
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adverse effects
3.Association of Apolipoprotein A5 (c.553G/T) gene polymorphism with hypertriglyceridemia of the Han Nationality in Zunyi
Xiao YU ; Huayu DAI ; Yezhong WANG ; Zhengguang GENG ; Zhimin ZHANG
The Journal of Practical Medicine 2016;32(20):3386-3390
Objective To investigate the relativity between c.553G/T polymorphism in exon 4 of Apolipoprotein A5 gene and hypertriglyceridemia (HTG) in Zunyi Han Nationality. Methods c.553G/T polymorphism of 103 HTG patients and 165 healthy individuals were tested by polymerase chain reaction and restriction fragment length (PCR-RFLP) assay. The distributions of genotypes and allele frequencies in HTG patients and healthy group were analyzed between Zunyi population and others. Results The genotype frequency of the Apo A5 gene c.553G/T showed statistical difference between patients group and normal groups (P < 0.05). The distribution of ApoA5 c.553T gene in HTG was higher than the normal group significantly (P < 0.05), and it had effect on triglyceridemia level independently (OR = 15.768, 95%CI: 5.916 ~ 42.025, P < 0.001). In the normal Han nationality groups, gene frequency of Zunyi was lower than that in Taiwan, Jiangsu and Hubei (P < 0.05), but similar to that in Hunan and Xinjiang (P > 0.05). In HTG groups, gene frequency of Zunyi was similar to that in Jiangsu (P>0.05), but higher than that in Xinjiang (P<0.05) and lower than that in Taiwan (P > 0.05). Conclusion There is relativity between Apo A5 gene c.553G/T polymorphisms and HTG in Zunyi Han nationality and the differences vary across different areas. It could be an independent risk factor for HTG.
4.Regulation of Nrf2 pathway to protect ventilator induce lung injury in vivo via inhibition of caveolin ;phosphorylation
Rong ZHONG ; Jun XIAO ; Chunguang DAI ; Zhihui YU ; Ji ZHOU
Chinese Critical Care Medicine 2016;28(6):547-552
Objective To investigate whether the inhibition of caveolin-1 (Cav-1) phosphorylation will regulate effectively nuclear factor-erythroid 2-related factor (Nrf2) signal pathway and downstream effector molecules and protest against ventilation induced lung injury (VILI) in an animal model in vivo. Methods Ninety male Sprague-Dawley (SD) rats were randomly divided into nine groups (each n = 10): sham group in which rats did not receive ventilation but received tracheotomy; lung protective ventilation (PV) for 1 hour or 2 hours group; mechanical ventilation (MV) at high volume tidal (VT, 40 mL/kg) for 1 hour or 2 hours group; protein tyrosine kinase inhibitor PP2 or rosiglitazone (Rsg) pretreatment + high VT ventilation for 1 hour or 2 hours groups. The two pretreatment groups were given intraperitoneal injection PP2 15 mg/kg or intragastric administration of Rsg 5 mg/kg 1 hour before ventilation respectively. The rats were sacrificed after model reproduction, and bronchoalveolar lavage fluid (BALF) was collected. Pulmonary vascular permeability was measured by Evans blue (EB). The levels of tumor necrosis factor-α (TNF-α), activator protein-1 (AP-1), nuclear factor-κB (NF-κB), and interleukin-8 (IL-8) in BALF were determined by enzyme linked immunosorbent assay (ELISA). Then the lung tissues were collected, the lung wet/dry ratio (W/D) was calculated, the changes in pathology was observed with light microscope, and myeloperoxidase (MPO) activity was determined by colorimetric analysis. Nrf2 mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR). The expressions of Cav-1 tyrosine residues 14 phosphorylation (pCav-1-Y14), Cav-1, peroxisome proliferators-activated receptor γ (PPARγ) and claudin-5 as well as Nrf2 in cytoplasm and nucleus were determined by Western Blot. The positive expressions of PPARγ and claudin-5 in lung tissues were assayed with immunohistochemistry staining. Results There were no obvious pathological changes in the lung tissue in sham group and PV groups, and there were no significant differences in all the parameters between the two groups either. However, the injury in lung tissue was severe in the high VT groups in which W/D ratio, EB contents, MPO activity, and TNF-α, AP-1, IL-8, NF-κB levels in BALF as well as the protein expressions of Cav-1 and pCav-1-Y14 were significantly higher than those of sham group and PV groups, and the protein expressions of PPARγ and claudin-5 were significant lower than those of sham group and PV groups with a dose-dependent manner; but Nrf2 expressions in cytoplasm and nucleus did not show a statistical increase. After pretreatment of PP2 or Rsg, W/D ratio, MPO activity, EB contents, TNF-α, AP-1, IL-8, and NF-κB in BALF were significantly decreased as compared with those of high VT group, and RT-PCR showed significant up-regulation of Nrf2 mRNA in lung tissues too. Moreover, there was a statistically significant increase in expressed Nrf2 proteins in nucleus in PP2 or Rsg groups as compared with those of high VT groups [Nrf2 in nucleus (gray value): 0.61±0.06, 0.56±0.06 vs. 0.31±0.02 at 1 hour, 0.38±0.06, 0.43±0.07 vs. 0.22±0.03 at 2 hours; all P < 0.05], but no significant difference was found in the expression of Nrf2 protein in the cytoplasm among all groups. The protein expressions of pCav-1-Y14 in PP2 pretreatment groups were significantly lower than those of high VT groups (gray value: 0.89±0.04 vs. 1.48±0.02 at 1 hour, 0.86±0.02 vs. 1.31±0.01 at 2 hours; both P < 0.05); but expressed PPARγ proteins and expressed claudin-5 proteins in PP2 or Rsg pretreatment groups were significantly higher than those of high VT groups [PPARγ (gray value): 0.34±0.07, 0.42±0.13 vs. 0.17±0.07 at 1 hour, 0.38±0.09, 0.33±0.07 vs. 0.16±0.03 at 2 hours; claudin-5 (gray value): 0.33±0.05, 0.38±0.07 vs. 0.14±0.03 at 1 hour; 0.30±0.06, 0.31±0.04 vs. 0.17±0.04 at 2 hours; all P < 0.05]. Conclusions The inhibition of Cav-1-Y14 phosphorylation can increase the expression of Nrf2 in the nucleus, then result in an increase in the protein expressions of PPARγ and claudin-5 of its effector molecules. This effect can reduce the inflammation and capillary permeability of lung tissue in the model of VILI.
5.Research on the effect of protection against ventilator-induced lung injury via regulation of caveolin-1/heme oxygenase-1 signaling
Rong ZHONG ; Jun XIAO ; Zhihui YU ; Ji ZHOU ; Chunguang DAI
Chinese Critical Care Medicine 2015;(7):568-573
ObjectiveTo determine whether the inhibition of caveolin-1 tyrosine residues 14 (Cav-1-Y14) phosphorylation with protein tyrosine kinase inhibitors (PP2) will upregulate heme oxygenase-1 (HO-1) activity to protect against ventilation induced lung injury in vivo of an animal model.Methods Fifty-four male Sprague-Dawley (SD) rats were randomly divided into nine groups (eachn = 6). Group A served as normal control group, in which rats did not receive ventilation but tracheotomy. Groups B1 and B2 received lung protective ventilation respectively for 1 hour or 2 hours. Groups C1 and C2 received high tidal volume (40 mL/kg) ventilation for 1 hour or 2 hours, respectively. The group D1 or D2 also received high tidal volume ventilation for 1 hour or 2 hour respectively, but they were given PP2 1 hour before high tidal volume ventilation. The groups E1 and E2 also received high tidal volume ventilation respectively for 1 hour or 2 hours, but tyrosine kinase inhibitor PP2 and HO-1 inhibitor zinc protoporphyrinⅨ(ZnPPⅨ) were given to animals 18 hours before high tidal volume ventilation. All the animals were sacrificed after ventilation, and the specimens of lung tissues and bronchoalveolar lavage fluid (BALF) were harvested. Then the changes in pathology of lung tissue was observed, and diffuse alveolar damage scores (DAD) were calculated, myeloperoxidase (MPO) activity was measured by colorimetric analysis, lung wet/dry ratio (W/D) was estimated. The expressions of phosphorylated caveolin-1 (P-Cav-1-Y14), caveolin-1 (Cav-1) and HO-1 were determined by Western Blot. The expressions of high mobility group B1 (HMGB1) and advanced glycation end product receptor (RAGE) in lung tissues were assayed with immunohistochemistry staining. The levels of tumor necrosis factor-α(TNF-α) in BALF were measured by enzyme linked immunosorbent assay (ELISA).Results There was no significant difference in all the parameters between group A and groups B. Compared with group B1, DAD score, W/D ratio, the activity of MPO and the concentration of TNF-α in BALF in group C1 were significantly increased [DAD score:7.97±0.59 vs. 0.55±0.13, W/D ratio: 5.70±1.61 vs. 5.04±0.63, MPO (U/g): 1.82±0.14 vs. 0.77±0.26, TNF-α(ng/L): 370.10±29.61 vs. 54.38±8.18, allP< 0.05], and the injury in ventilation 2 hours group was more serious than that in ventilation 1 hour group. Compared with groups C, all the parameters in groups D were significantly decreased. The parameters in groups E were significantly higher than those in groups A, B, and D, but no significant difference was found as compared with groups C. Compared with groups B, the protein expressions of Cav-1 and P-Cav-1-Y14 (gray value) in groups C were significantly increased (1 hour: 1.49±0.02 vs. 1.26±0.13, 1.34±0.02 vs. 0.87±0.04;2 hours: 1.58±0.02 vs. 1.27±0.27, 1.31±0.01 vs. 0.95±0.02, allP< 0.05), and the expression of HO-1 protein (gray value) was significantly decreased (1 hour: 0.59±0.02 vs. 1.10±0.01, 2 hours: 0.49±0.01 vs. 1.20±0.02, both P< 0.05). No significant difference in Cav-1 protein expression between groups D as well as groups E and groups C. The protein expression of P-Cav-1-Y14 in groups D and E was significantly lower than that in groups C. The protein expression of HO-1 in groups D was significantly higher than that in groups C, but the phenomenon was not found in groups E as compared with groups C. Compared with group A, the positive expression of HMGB1 and RAGE in lung tissue in groups C and E was significantly increased, but no significant difference was found between groups B as well as groups D and group A.Conclusion Cav-1-Y14 phosphorylation is the key factor for ventilator induced lung injury, which can not only lead to a decrease in vascular barrier function, but also inhibit the activity of HO-1 enzyme, thus further aggravates inflammatory injury of the lung as induced by mechanical ventilation.
6.Curative effect evaluation between improved frontolateral partial laryngectomy and improved cricohyoidoepiglottopexy
Hao TIAN ; Jianjun YU ; Zan LI ; Xiao ZHOU ; Jie DAI
China Oncology 2013;(7):535-539
Background and purpose:Nowadays, about therapy of laryngeal carcinoma, people are paying more and more widely attention to ifnding out how to improve quality of patients’ life besides radical surgery. For glottic laryngeal carcinoma which invading anterior commissure or bilateral vocal cord, we performed modiifed frontolateral partial laryngectomy or modiifed cricohyoidoepiglottopexy, and contrastive analyzed the therapeutic efifcacy of the two ways. Methods:Sixty cases patients of glottic laryngeal carcinoma who treated in Hunan Provincial Tumor Hospital during 2005 to 2010, which invaded the anterior commissure or bilateral vocal cord, were randomly attributed to two groups as A and B;30 patients of group A were underwent modiifed frontolateral partial laryngectomy and repaired with bilateral sternohyoid muscle lfap, 30 patients of group B were treated by modiifed cricohyoidoepiglottopexy. Follow-up time of each patient was 5 years postoperation and clinical data were retrospectively analyzed. Results:The 5-year survival rate was 86.7%in group A as well as 83.3%in group B, and there was no statistical difference between two groups (P=0.718). Pronunciation function:22 cases in group A and 21 cases in group B whose pronunciation function can be competent in the noisy environment, and can pronounce“a”and“i”vowel;8 cases in group A and 9 cases in group B can pronounce only a“ha”,“hi”sound, that couldn’t communicate with others in a noisy environment. There was no statistical difference in pronunciation function between the two groups (P=0.774). Incidence of deglutition disorder 4 weeks postoperation:group A was 0 (0/30), group B was 16.7%(5/30), and the difference between the two groups was statistically signiifcant (P=0.026);average time of extubation postoperation:group A was (10±2.3) d, group B was (20±4.6)d, and the difference between the two groups was statistically signiifcant (P=0.0000);recurrence rate of dyspnea after extubation:group A was 16.7%(5/30), group B was 0 (0/30), and there was statistically signiifcant difference between the two groups (P=0.026). Conclusion: For the glottic laryngeal carcinoma which invading anterior commissure or bilateral vocal cord, there was no statistical difference in 5-years survival rate and function of pronunciation between modified frontolateral partial laryngenctomy and modified cricohyoidoepiglottopexy postoperation. The former had less postoperative deglution disorder, earlier extubation time, and to some extent, alleviated the suffering of the patients, but part of these patients needed secondary surgery due to dyspnea which resulted by radioactive tissue adhesion after extubation. The latter had more serious deglution disorder postoperation, longer recovery time, and relatively longer time to extubating, showed no again dyspnea after extubation, and had more extensive adaptation disease. In a word, each way of operation has its advantage respectively.
7.Regulation of paxillin tyrosine phosphorylation via inhibition of c-Abl kinase to protect ventilator induce lung injury in vivo in rats
Rong ZHONG ; Jun XIAO ; Chunguang DAI ; Zhihui YU
Chinese Critical Care Medicine 2017;29(7):596-601
Objective To determine whether the inhibition of paxillin tyrosine residues 31 and tyrosine residues 118 (Pxn Y31 and Pxn Y118) phosphorylation via inhibition of c-Abl kinase will effectively block its downstream effector molecules vessel endothelium-cadherin (VE-cad), and whether Rho/Rho kinase activation which will induce the vascular barrier dysfunction. Methods Ninety healthy male Sprague-Dawley (SD) rats were randomly divided into nine groups (each n =10). Only tracheotomy was undergone in the sham group. Groups of protective ventilation were set at a volume tidal (VT) of 6 mL/kg, a positive end-expiratory pressure (PEEP) of 5 cmH2O (1 cmH2O =0.098 kPa) for 1 hour or 2 hours (namely group PVT 1 h and group PVT 2 h), respectively. Groups of high VT were put on mechanical ventilation (MV) at high VT 30 mL/kg, PEEP 0 for 1 hour or 2 hours (namely group HVT 1 h and group HVT 2 h), respectively. Groups UO126 and AG957 pretreatment were set on MV at HVT for 1 hour or 2 hour respectively, but they were given p42/44 mitogen-activated protein kinase (p42/44MAPK) inhibitor UO1261 mg/kg by intraperitoneal injection or c-Abl kinase inhibitor AG95710 mL/kg by intragastric injection 1 hour before HVT ventilation. All the animals were sacrificed after experiments and specimens of lung tissues and bronchoalveolar lavage fluid (BALF) were harvested. Pulmonary vascular permeability was measured by Evans blue (EB). The levels of tumor necrosis factor-α(TNF-α) in BALF were measured by enzyme linked immunosorbent assay (ELISA). Then the change of lung tissue pathology was observed with light microscope, diffuse alveolar damage system (DAD) score and lung wet/dry ratio (W/D) were estimated. The myeloperoxidase (MPO) activity was measured by colorimetric analysis, phosphorylations of c-Abl Y245, Pxn Y31, Pxn Y118, VE-cad Y658, p42/44MAPK Y202/Y204, myosin light chain (MLC) and myosin-associated phosphatasetype Y696 (MYPT Y696) were determined by Western Blot. Results ① There were no obvious pathological changes in the lung tissue in the sham group and PVT 1 h or 2 h group, and also there were no significant differences in all the parameters between above groups. However, the injury in lung tissue was severe in the HVT groups. In addition, DAD score, lung W/D ratio, EB content, the activity of MPO, and TNF-α in BALF in HVT groups were significantly higher than those in sham group and PVT groups. After pretreatment with AG957 or UO126, all the parameters were significantly decreased as compared with those of groups HVT. ② The levels of phosphorylation of the proteins in lung tissue in HVT groups were increased as compared with those of group sham and groups PVT, especially at 2 hours of MV. However, compared with groups HVT, the level of p-VE-cad Y658 in lung tissue decreased significantly in group AG957 and group UO126 at 2 hours after HVT. However, the levels of all phosphorylated proteins at 2 hours were significantly lowered in the AG957 group compared with those of the HVT group [p-c-Abl Y245 (gray value): 0.29±0.04 vs. 0.42±0.04, p-Pxn Y31 (gray value): 0.51±0.03 vs. 0.70±0.05, p-Pxn Y118 (gray value):0.65±0.04 vs. 0.91±0.04, p-VE-cad Y658 (gray value): 0.77±0.07 vs. 1.32±0.07, p-p42/44MAPK Y202/Y204 (gray value): 0.38±0.06 vs. 0.61±0.03, p-MLC (gray value): 0.37±0.04 vs. 0.77±0.05, p-MYPT Y696 (gray value):0.54±0.05 vs. 0.87±0.06, all P < 0.05]. After pretreatment with UO126, the phosphorylation level of VE-cad in lung tissue at 2 hours was significantly lower than that of HVT group (gray value: 0.74±0.04 vs. 1.32±0.07), and the phosphorylation levels of p42/44MAPK and its downstream effector molecules MLC and MYPT Y696 were also significantly decreased [p-p42/44MAPK Y202/Y204 (gray value): 0.38±0.07 vs. 0.61±0.03, p-MLC (gray value):0.37±0.04 vs. 0.77±0.05, p-MYPT Y696 (gray value): 0.55±0.05 vs. 0.87±0.06, all P < 0.05]. Conclusions Pxn Y31 and Pxn Y118 phosphorylation could be blocked by inhibition of c-Abl kinase, which could strengthen VE-cad at attachment junction and might block formation of Pxn-guanine nucleotide-exchange factor H1 (GEF-H1)-p44/42MAPK signalosome which induce activation local Rho signaling, lead to activation of MLC phosphorylation, actomyosin contraction, and increase endothelial permeability.
8.Review: plant polyphenols modulate lipid metabolism and related molecular mechanism.
Yan-li DAI ; Yu-xiao ZOU ; Fan LIU ; Hong-zhi LI
China Journal of Chinese Materia Medica 2015;40(21):4136-4141
Lipid metabolism disorder is an important risk factor to obesity, hyperlipidemia and type 2 diabetes as well as other chronic metabolic disease. It is also a key target in preventing metabolic syndrome, chronic disease prevention. Plant polyphenol plays an important role in maintaining or improving lipid profile in a variety of ways. including regulating cholesterol absorption, inhibiting synthesis and secretion of triglyceride, and lowering plasma low density lipoprotein oxidation, etc. The purpose of this article is to review the lipid regulation effects of plant polyphenols and its related mechanisms.
Animals
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Humans
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Lipid Metabolism
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drug effects
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Metabolic Diseases
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drug therapy
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metabolism
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Polyphenols
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pharmacology
9.Preparation and characterization of cucurbitacin B sodium deoxycholate/phospholipid-mixed oral fast dissolving film and antitumor activity study.
Chao YU ; Yun-Zhi XIAO ; Ping-Hua XUN ; Ling DAI ; Jin HAN ; Hai-Long YUAN
China Journal of Chinese Materia Medica 2014;39(10):1799-1804
A novel drug delivery system combining oral fast dissolving film with sodium deoxycholate/phospholipid mixed micelles was prepared to increase the absorption of cucurbitacin B that is a poor aqueous solubility substance. Encapsulation efficiency, particle size, zeta potential, polydispersity coefficient, investigated the morphology, disintegration time of oral fast dissolving film and the pharmacodynamic properties of cucurbitacin B sodium deoxycholate/phospholipid-mixed micelles before and after solidified in mice were evaluated and compared. The oral fast dissolving film prepared in this study showed a homogeneous pale yellow and could completely disintegrated in the 30 s. It could meet the requirements of rapidly disintegrating fully. The encapsulation efficiency, particle size, zeta potential, polydispersity coefficient of cucurbitacin B sodium deoxycholate/phospholipid-mixed micelles loaded in oral fast dissolving film were (43.36 +/- 2.12)%, (108.82 +/- 5.2) nm, (-34.18 +/- 1.07) mV, 0.088 +/- 0.012, respectively. The encapsulation efficiency, particle size, zeta potential, polydispersity coefficient of cucurbitacin B sodium deoxycholate/phospholipid-mixed micelles in solution were (41.26 +/- 2.22)%, (181.82 +/- 4.48) nm, (-30.67 +/- 0.81) mV, 0.092 +/- 0.012, respectively. The difference of pharmacodynamics among film of cucurbitacin B-loaded micelles, cucurbitacin B-loaded micelles and free cucurbitacin B in vivo was compared. Solubility of cucurbitacin B loaded in sodium deoxycholate/phospholipid-mixed micelles has also been greatly improved. The tumor inhibition rate of cucurbitacin B loaded in sodium deoxycholate/phospholipid-mixed micelles was significantly improved and did not change significantly before and after solidified. These showed that the sodium deoxycholate/phospholipid-mixed micelles could enhance the antitumor activities of cucurbitacin B and the stability of cucurbitacin B sodium deoxycholate/phospholipid-mixed micelles was improved significantly after solidified by oral fast dissolving film technology without pharmacodynamic properties changed significantly.
Animals
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Antineoplastic Agents
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administration & dosage
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chemistry
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Cell Line, Tumor
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Deoxycholic Acid
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chemistry
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Drug Carriers
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chemistry
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Humans
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Male
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Mice
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Neoplasms
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drug therapy
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Phospholipids
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chemistry
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Solubility
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Triterpenes
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administration & dosage
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chemistry
10.Expressions of Let-7 in Normal Breast Tissue and Breast Cancer Tissue
Zhen YU ; Mingyao XIAO ; Ming CUI ; Min LIU ; Shuying DAI ; Ying CHEN ; Yuefeng HE
Journal of Kunming Medical University 2016;37(7):19-21
Objective To study the expression characteristics of Let-7 genes in breast cancer.Methods Twenty-eight patients with breast cancer were randomly selected,and their cancer tissue and adjacent normal tissue were collected.TRIzol was used to extract the total RNA and real-time quantitative PCR was used to detect the relative gene expression levels.Results The expression of precursor Let-7 in cancer tissue was (9.65 ± 2.31),which was lower than that in normal tissue (10.05 ± 2.81),P =0.048.Precursor Let-7 had dependence relationship with the long menstruation (b =0.816,P =0.029).The menarche age showed a positive correlation with precursor Let-7 in normal tissue (r =0.502,P =0.048) and a negative correlation in cancer tissue (r =-0.484,P =0.049) Conclusions The expression of precursor Let-7 in cancer tissue is lower than that in normal tissue.The period of menstruation is a protective factor to breast cancer.