1.Preparation of calcium phosphate nanoflowers and evaluation of their antioxidant and osteogenic induction capabilities in vitro.
Mingyu JIA ; Zhihong CHEN ; Huajian ZHOU ; Yukang ZHANG ; Min WU
Chinese Journal of Reparative and Reconstructive Surgery 2025;39(9):1203-1211
OBJECTIVE:
To investigate the antioxidant and osteogenic induction capabilities of calcium phosphate nanoflowers (hereinafter referred to as nanoflowers) in vitro at different concentrations.
METHODS:
Nanoflowers were prepared using gelatin, tripolyphosphate, and calcium chloride. Their morphology, microstructure, elemental composition and distribution, diameter, and molecular constitution were characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive spectroscopy. Femurs and tibias were harvested from twelve 4-week-old Sprague Dawley rats, and bone marrow mesenchymal stem cells (BMSCs) were isolated and cultured using the whole bone marrow adherent method, followed by passaging. The third passage cells were identified as stem cells by flow cytometry and then co-cultured with nanoflowers at concentrations of 0, 0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2, and 3.6 mg/mL. Cell counting kit 8 (CCK-8) assay was performed to screen for the optimal concentration that demonstrated the best cell viability, which was subsequently used as the experimental concentration for further studies. After co-culturing BMSCs with the screened concentration of nanoflowers, the biocompatibility of the nanoflowers was verified through live/dead cell staining, scratch assay, and cytoskeleton staining. The antioxidant capacity was assessed by using reactive oxygen species (ROS) fluorescence staining. The in vitro osteoinductive ability was evaluated via alkaline phosphatase (ALP) staining, alizarin red staining, and immunofluorescence staining of osteocalcin (OCN) and Runt-related transcription factor 2 (RUNX2). All the above indicators were compared with the control group of normally cultured BMSCs without the addition of nanoflowers.
RESULTS:
Scanning electron microscopy revealed that the prepared nanoflowers exhibited a flower-like structure; transmission electron microscopy scans discovered that the nanoflowers possessed a multi-layered structure, and high-magnification images displayed continuous atomic arrangements, with the nanoflower diameter measuring (2.00±0.25) μm; energy-dispersive spectroscopy indicated that the nanoflowers contained elements such as C, N, O, P, and Ca, which were uniformly distributed across the flower region; Fourier transform infrared spectroscopy analyzed the absorption peaks of each component, demonstrating the successful preparation of the nanoflowers. Through CCK-8 screening, the concentrations of 0.8, 1.2, and 1.6 mg/mL were selected for subsequent experiments. The live/dead cell staining showed that nanoflowers at different concentrations exhibited good cell compatibility, with the 1.2 mg/mL concentration being the best (P<0.05). The scratch assay results indicated that the cell migration ability in the 1.2 mg/mL group was superior to the other groups (P<0.05). The cytoskeleton staining revealed that the cell morphology was well-extended in all concentration groups, with no significant difference compared to the control group. The ROS fluorescence staining demonstrated that the ROS fluorescence in all concentration groups decreased compared to the control group after lipopolysaccharide induction (P<0.05), with the 1.2 mg/mL group showing the weakest fluorescence. The ALP staining showed blue-purple nodular deposits around the cells in all groups, with the 1.2 mg/mL group being significantly more prominent. The alizarin red staining displayed orange-red mineralized nodules around the cells in all groups, with the 1.2 mg/mL group having more and denser nodules. The immunofluorescence staining revealed that the expressions of RUNX2 and OCN proteins in all concentration groups increased compared to the control group, with the 1.2 mg/mL group showing the strongest protein expression (P<0.05).
CONCLUSION
The study successfully prepares nanoflowers, among which the 1.2 mg/mL nanoflowers exhibits excellent cell compatibility, antioxidant properties, and osteogenic induction capability, demonstrating their potential as an artificial bone substitute material.
Animals
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Osteogenesis/drug effects*
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Mesenchymal Stem Cells/drug effects*
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Calcium Phosphates/pharmacology*
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Rats, Sprague-Dawley
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Rats
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Antioxidants/chemistry*
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Cells, Cultured
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Cell Differentiation/drug effects*
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Nanostructures/chemistry*
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Tissue Engineering/methods*
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Bone Marrow Cells/cytology*
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Coculture Techniques
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Tissue Scaffolds/chemistry*
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Male
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Biocompatible Materials/chemistry*
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Cell Survival
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Core Binding Factor Alpha 1 Subunit/metabolism*
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Cell Proliferation
2.Seven thyroid imaging reporting and data systems for differentiating benign and malignant thyroid nodules under the context of Hashimoto thyroiditis
Xin SUN ; Wei ZHANG ; Linggang CHENG ; Yang GUANG ; Yukang ZHANG
Chinese Journal of Medical Imaging Technology 2024;40(2):212-216
Objective To compare the value of 7 different thyroid imaging reporting and data systems(TI-RADS)for differentiating benign and malignant thyroid nodules under the context of Hashimoto thyroiditis(HT).Methods A total of 338 thyroid nodules in 200 HT patients were enrolled,including 167 benign and 171 malignant ones.Kwak-TIRADS,American Thyroid Association(ATA)guideline,American Association of Clinical Endocrinologists(A ACE)/American College of Endocrinology(ACE)/Associazione Medici Endocrinologi(AME)guideline,K-TIRADS of Korean Society of Thyroid Radiology,EU-TIRADS of European Thyroid Association,American College of Radiology(ACR)-TIRADS and 2020 Chinese guidelines for malignant risk stratification of thyroid nodules by ultrasound proposed by the superficial organs and vessels group of the ultrasound medicine branch of the Chinese Medical Association(C-TIRADS)were used for grading of benign and malignant thyroid nodules.Taken pathological results as gold standards,the diagnostic efficacy of 7 kinds of TI-RADS were analyzed.Results The sensitivity of Kwak-TIRADS,ATA guideline,A ACE/ACE/AME guideline,K-TIRADS,EU-TIRADS,ACR-TIRADS and C-TIRADS for differentiating benign and malignant thyroid nodules under the context of HT was 97.08%,98.25%,99.42%,95.91%,99.42%,90.06%and 99.42%,respectively,the specificity was 88.02%,83.23%,82.04%,88.02%,82.04%,86.83%and 84.43%,respectively,and the area under the curve(AUC)was 0.946,0.913,0.907,0.934,0.909,0.916 and 0.960,respectively.The sensitivity of C-TIRADS,EU-TIRADS and A ACE/ACE/AME guideline were all higher than that of K-TIRADS and ACR-TIRADS(all P<0.05),and the specificity of Kawk-TIRADS and K-TIRADS were both higher than that of C-TIRADS,ATA guideline,EU-TIRADS and AACE/ACE/AME guideline(all P<0.05),while AUC of C-TIRADS and Kawk-TIRADS were both higher than that of the rest 5 kinds of TI-RADS(all P<0.05).According to Kwak-TIRADS,ATA guideline,AACE/ACE/AME guideline,K-TIRADS,EU-TIRADS,ACR-TIRADS and C-TIRADS,the malignant rate of different grades nodules identified with the same TI-RADS were significant different(all P<0.05),which all raised with the increase of TI-RADS grade.Conclusion C-TIRADS and Kawk-TIRADS had better value for differentiating benign and malignant thyroid nodules under the context of HT,among which C-TIRADS had higher sensitivity and Kawk-TIRADS had higher specificity.
3.Biological and physicochemical properties of bioactive ion modified brushite cements
Cheng ZENG ; Huanhuan YU ; Yukang GONG ; Chenhao WANG ; Yinen ZHANG ; Wenshan GAO
Chinese Journal of Tissue Engineering Research 2024;28(22):3561-3568
BACKGROUND:As a bone replacement and filling material,calcium phosphate stone bone cement has good biocompatibility,bone conductivity,and other advantages,especially its better biodegradability compared to other calcium phosphate bone cements.It has important application value in bone repair.However,due to its limitations such as insufficient mechanical properties,fast solidification reaction,and poor injection performance,it is currently only suitable for the repair of non weight-bearing bone. OBJECTIVE:To explore the modification of brushite cements with bioactive ions(metal and non metal ions)to expand its application range. METHODS:The author used PubMed,ScienceDirect,CNKI,and WanFang to search the literature published between 2018 and 2023 with the search terms"metal ion,iron,copper,strontium,magnesium,zinc,non-metal ion,modification,bone,brushite cements"in Chinese and"metal ion,iron,Fe,copper,Cu,strontium,Sr,magnesium,Mg,zinc,Zn,non-metal ion,modification,bone,brushite cements"in English.After reading titles and abstracts,the articles were initially screened,and irrelevant and duplicate articles were excluded.Finally,64 articles were included for review. RESULTS AND CONCLUSION:(1)Bioactive ions affect the hydration process of calcium phosphate bone cement.Different ions are substituted by ions and incorporated into the crystal structure of calcium phosphate bone cement,changing the crystal morphology of the cement and causing changes in physical and chemical properties such as setting time,injectability,and compressive strength.(2)Ionic modified calcium phosphate bone cement produces different ion release effects due to different crystal structures.Different types of ions have properties such as promoting angiogenesis/osteogenesis,antibacterial,anti-tumor,etc.In addition,calcium phosphate bone cement has good biodegradability,which has great advantages for the performance of various ions.(3)The physicochemical properties of calcium phosphate bone cement modified with different ions are as follows:iron,copper,strontium,magnesium,zinc,silver,and cobalt can prolong the setting time.Strontium,and magnesium can improve injection performance.Copper,strontium,magnesium,silver and silicon can enhance compressive strength.The ions that can simultaneously improve the three physical and chemical properties of calcium phosphate bone cement include strontium and magnesium.Good physical and chemical properties are a prerequisite for clinical application,so improving the setting time,injectability,compressive strength,and other properties of calcium phosphate bone cement with ions is of great significance for the research and application of bone cement.(4)The biological properties of calcium phosphate bone cement modified with different ions are as follows:copper,strontium,magnesium,zinc,cobalt,lithium,selenium,and silicon have promoting angiogenesis/osteogenic effects.Iron,copper,magnesium,zinc,and silver have antibacterial properties.Magnesium ions have anti-inflammatory properties.Copper and selenium have anti-tumor properties.(5)In summary,magnesium ions can improve the setting time,injectability,and compressive strength of calcium phosphate bone cement,while also promoting neovascularization/osteogenesis,antibacterial properties,and have good application prospects for the treatment of bone defects with concurrent infections.In addition,copper also has anti-tumor properties,so copper ions have great potential in the treatment of bone defects caused by infections and tumors.However,relevant research is still in the basic research stage,and the effects of different ion doping concentrations and synthesis conditions on the physicochemical properties of calcium phosphate bone cement need to be further explored.At the same time,the impact of biological properties also needs to be studied and observed for a longer period of time.
4.Correlations of clinical,multi-modal ultrasonic and pathological features of papillary thyroid carcinoma with BRAF V600E mutation
Xin SUN ; Wei ZHANG ; Linggang CHENG ; Yang GUANG ; Yukang ZHANG
Chinese Journal of Medical Imaging Technology 2024;40(5):730-734
Objective To observe the correlations of clinical,multi-modal ultrasonic and pathological features of papillary thyroid carcinoma(PTC)with BRAF V600E mutation.Methods Patients with clinically suspected malignant thyroid lesions were prospectively collected.After the results of pathology and gene test were obtained,PTC patients were divided into BRAF V600E mutation(+)(mutant group)and BRAF V600E mutation(-)(wild-type group)according to BRAF V600E gene test.Univariate analysis and multivariate logistic regression were used to compare clinical,conventional ultrasound,contrast-enhanced ultrasound(CEUS)and pathological manifestations between groups,so as to screen the independent risk factors of PTC BRAF V600E gene mutation.Results A total of 116 PTC patients(116 lesions)were enrolled,including 77 in mutant group and 39 in wild-type group.Statistical differences of thyroid peroxidase antibody(TPO-Ab)level,lesion size,orientation,margin and microcalcification observed on conventional ultrasound,changes of lesion size and the mean transit time(MTT)shown on CEUS,as well as of extramembranous invasion,cervical central lymph node metastasis,complicated with benign nodules shown by pathology were found between groups(all P<0.05).TPO-Ab level,lesion orientation and changes of lesion size after enhancement shown by multi-modal ultrasound,and pathological cervical central lymph node metastasis were all independent predictive factors for PTC BRAF V600E gene mutation(OR=0.175,3.868,5.769,6.943,all P<0.05).Conclusion Patients'TPO-Ab level,lesion orientation,changes of lesion size after enhancement shown by multi-modal ultrasound and pathological cervical central lymph node metastasis were all independently associated with PTC BRAF V600E gene mutation.
5.Time-related association between fluid balance and prognosis in sepsis patients: a cohort study based on MIMIC-IV database.
Rui HUANG ; Yukang DONG ; Yongfang ZHOU ; Longjiu ZHANG ; Jiong XIONG ; Jiangquan FU
Chinese Critical Care Medicine 2023;35(11):1182-1187
OBJECTIVE:
To investigate time-related association between fluid balance and prognosis in sepsis patients.
METHODS:
A retrospective cohort study was conducted based on the data of sepsis patients in the Medical Information Database for Intensive Care-IV 2.0 (MIMIC-IV 2.0) from 2008 to 2019. Sepsis patients aged ≥ 18 years who were admitted to intensive care unit (ICU) for at least 2 days were included. The daily fluid balance and cumulative fluid balance (CFB) were calculated from days 1 to 7 after ICU admission. According to CFB,the patients were divided into negative fluid balance group (CFB% < 0%), fluid balance group (0% ≤ CFB% ≤ 10%), and fluid overload group (CFB% > 10%). In-hospital mortality was the primary outcome. Multifactorial Logistic regression was used to analyze time-related association between different CFB and the risk of in-hospital mortality in patients with sepsis during 7 days after ICU admission. In addition, subgroup analysis was performed on patients with septic shock and patients with sepsis who stayed in the ICU for 7 days or longer.
RESULTS:
A total of 11 437 patients with sepsis were included, of which 6 595 were male and 4 842 were female. The mean age was (64.4±16.4) years. A total of 10 253 patients (89.6%) survived and 1 184 patients (10.4%) died during hospitalization. Compared with the survival group, patients in the death group were older, lighter, had higher sequential organ failure assessment (SOFA), simplified acute physiology score II (SAPS II), longer ICU stay, higher incidence of septic shock, and higher proportion of invasive mechanical ventilation, renal replacement therapy (RRT) and vasoactive drugs. In terms of comorbidities, congestive heart failure, renal disease, liver disease, and malignancy were more common in the death group. The death group had a higher daily fluid balance than the survival group during 7 days after ICU admission, the CFB in the two groups gradually increased with length of ICU stay. After adjusting variables such as age, gender, race, SOFA score, SAPS II score, comorbidities, and the use of invasive mechanical ventilation, RRT and vasoactive drugs, multivariate Logistic regression analysis showed that fluid overload on day 1 after ICU admission was a protective factor for the reduced risk of in-hospital mortality in sepsis patients [odds ratio (OR) = 0.74, 95% confidence interval (95%CI) was 0.64-0.86, P = 0.001]. However, fluid overload on day 3 was a risk factor for in-hospital mortality in sepsis patients (OR = 1.70, 95%CI was 1.47-1.97, P < 0.001) and the risk of in-hospital mortality was significantly increased from day 4 to day 7. Furthermore, the same results were obtained in patients with septic shock and sepsis patients who stayed in the ICU for 7 days or longer.
CONCLUSIONS
Fluid overload on day 1 was associated with reduced in-hospital mortality. However, from the third day, fluid overload increases the risk of in-hospital mortality. Thus, managing fluid balance at different times may improve prognosis.
Humans
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Male
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Female
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Middle Aged
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Aged
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Aged, 80 and over
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Shock, Septic
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Cohort Studies
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Retrospective Studies
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Sepsis
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Intensive Care Units
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Water-Electrolyte Balance
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Heart Failure
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Prognosis
6.Three-dimensional ultrasonography for evaluation of development of fetal anal sphincter
Yang GUANG ; Wen HE ; Hongxia ZHANG ; Yukang ZHANG ; Bin NING ; Tengfei YU
Chinese Journal of Medical Ultrasound (Electronic Edition) 2019;16(5):380-385
Objective To investigate the capability oftomography ultrasound (TUI) in evaluating the development of the normal anorectal structure to provide a reference for prenatal diagnosis of imperforate anus.Methods From June 2017 to July 2018,315 singleton pregnant women at 19-40 weeks of gestational age were selected from Beijing Tiantan Hospital,and they ranged in age from 23 to 40 years,with an average age of 29±3 years.The TUI technique was applied to measure the fetal anal sphincter diameter (ASD),anal canal diameter (ACD),and anal canal length (ACL).The correlation between ASD,ACD,or ACL and gestational age was analyzed by Pearson correlation analysis,and the regression equation and curve were established.The intraclass correlation coefficient (ICC) and 95% confidence interval (CI) were used to evaluate the repeatability of the measurement ofASD,ACD,and ACL.Results The display rate of fetal anorectum in all fetuses by the TUI technique was 97.8% (308/315).Pearson correlation analysis showed that the normal fetal ASD,ACD,and ACL were positively correlated with the gestational age of the fetus,and the regression equations are:ASD,Y=-0.001X2 + 0.421X-1.726 (r=0.83,P < 0.01);ACD,Y=0.418X-4.207 (r=0.89,P < 0.01);and ACL,Y=0.526X-1.062 (r=0.87,P < 0.01).Conclusion TUI for assessment of fetal anorectum is feasible.This method can be applied to improve the display rate of fetal anorectum.
7.Advances in research on ultrasound-guided percutaneous ethanol injection for treatment of benign cystic thyroid nodules
Yukang ZHANG ; Lijuan NIU ; Junying LIU ; Zhengjiang LI
China Oncology 2016;(1):112-116
Because of development and popularization of the ultrasound techniques, the detection rate of nodal thyroid has increased. Surgery is the long-established therapeutic option. However, due to the surgical trauma, compli-cations and the effect on quality of life, various minimally invasive treatments have been proposed and widely used. A large number of foreign studies have shown that ultrasound-guided percutaneous ethanol injection is a more commonly used minimally invasive way to treat benign pure cystic and predominantly cystic thyroid nodules. This article provides an up-to-date review of the overseas studies and summarized on percutaneous ethanol injection for the treatment of benign cystic thyroid nodules.
8.Impact of intestinal ischemia/reperfusion on free amino acid levels in plasma
Yukang WANG ; Guizhen HE ; Rui ZHANG
Chinese Journal of Clinical Nutrition 2013;21(1):17-22
Objective To investigate intestinal mucosal injury and the change of free amino acid levels in plasma with intestinal ischemia/reperfusion.Methods Twenty-four Sprague-Dawley (SD) male rats (SPF grade) were randomly divided into 3 groups with 8 rats in each group:Blank group,Sham group and ischemia/reperfusion (I/R) group.The rats in I/R group were subjected to 60 min ischemia by clamping the superior mesenteric artery (SMA),followed by 120 min repeffusion.All rats were sacrificed with blood withdraw through inferior vena cava.The plasma was precipitated with Sulfosalicylic acid and the supernatant free amino acid levels were measured and the intestinal mucosal thickness and villus length were also assayed.Results In the I/R group the total free amino acids,essential amino acids (EAA),glutamine and branched-chain amino acids (BCCA) were remarkably lower [the total free amino acids:I/R vs Blank vs Sham:(4585.1 326.1) vs (5661.5 ±581.9) vs (5337.9±998.7) μmol/L (F=5.075,P=0.016); EAA:I/Rvs Blank vs Sham:(1401.3 ±183.4) vs (2147.6 ± 265.1) vs (1796.2 ± 440.8) μmol/L (F =1 1.216,P =0.000) ; glutamine:I/R vs Blank vs Sham:(646.1 ± 34.7) vs (895.7 ± 258.8) vs (839.1 ± 163.7) μmol/L (F =4.326,P =0.027) ; BCCA:I/R vs Blank vs Sham:(507.8 ± 119.0) vs (912.2 ± 165.8) vs (671.9 ± 79.8) μmol/L (F =10.662,P =0.001)]and the jejunum and ileum mucosal thickness and villus height were decreased compared to Blank and Sham groups [jejunum mucosal thickness:I/R vs Blank vs Sham:(401.50 ± 117.79) vs (529.22 ±54.73) vs (499.54 ±64.48) μm (F=31.869,P =0.000) ; jejunum villus height:I/R vs Blank vs Sham:(271.37 ± 84.29) vs (365.26 ± 46.98) vs (349.67 ± 56.11) μm (F =30.472,P =0.000) ; ileum mucosal thickness:I/R vs Blank vs Sham:(254.20 ± 43.56) vs (324.70 ± 30.56) vs (298.26 ± 58.46) μm (F =30.442,P =0.000) ; ileum villus height:I/R vs Blank vs Sham:(169.37 ± 37.25) vs (221.62 ± 37.26) vs (193.25 ± 38.39) μm (F =24.145,P =0.000)],and The EAA and BCAA in the I/R group were lower than the Sham group (respectively,P <0.05).There was no significant difference in aromatic amino acids (AAA) among the three groups [I/R vs Blank vs Sham:(273.2 ± 37.4) vs (296.8 ± 55.6) vs (281.9 ± 7.3) μmol/L (F =0.578,P =0.570)].The ratio BCAA/AAA in the Sham and I/R groups were significantly lower than the Blank group [(I/R vs Blank vs Sham:(2.4 ±0.6) vs.(1.9 ±0.4) vs (3.1 ±0.7) (F =5.215,P =0.014)],while the I/R group was decreased slightly compared to the Sham group,but the difference was not significant (P > 0.05).The ethanolamine phosphate,taurine,citrulline,cystine,phosphoserine levels were reduced in the Sham and I/R groups compared to the Blank group [ethanolamine phosphate:I/R vs Blank vs Sham:(11.4 ± 1.9) vs (14.3 ± 3.4) vs (10.1±1.7) μmol/L(F=5.897,P=0.009);taurine:I/R vs BlankvsSham:(341.1±36.3) vs(533.2±90.8) vs (439.2±105.4) μmol/L (F=10.702,P=0.001); citrulline:I/R vs Blank vs Sham:(57.7±3.2) vs (73.1 ±16.2) vs (58.1 ±3.8) μmol/L (F=6.360,P =0.007); cystine:I/R vs Blank vs Sham:(20.0 ± 3.6) vs (60.6 ± 24.6) vs (36.3 ± 5.8) μmol/L (F =15.344,P =0.000) ; phosphoserine:I/R vs BlankvsSham:(10.2±1.1) vs (15.8±5.4) vs (11.7 ±3.4) μmol/L (F=4.878,P=0.018)],and the taurine and cystine in I/R groups were significantly decreased than the Sham group (respectively,P < 0.05).The ornithine and arginine were comparatively reduced in I/R in contrast to the Blank and Sham groups [ornithine:I/R vs Blank vs Sham:(81.5 ± 19.0) vs (125.5 ±42.3) vs (114.9 ± 19.5) μmol/L (F =4.961,P =0.017) ;arginine:I/R vs Blank vs Sham:(199.2 ± 8.0) vs (258.9 ± 14.6) vs (248.7 ± 38.4) μmol/L (F =13.940,P =0.000)].The tryptophan and glutamic acid concentrations were increased in the Sham and I/R groups [tryptophan:L/R vs Blank vs Sham:(125.9 ± 12.1) vs (103.1 ± 29.9) vs (128.9 ± 18.5) μmol/L (F =5.429,P =0.031) ; glutamic acid:I/R vs Blank vs Sham:(188.6 ± 29.8) vs (93.6 ± 29.4) vs (125.4 ± 43.8) μmol/L (F =15.241,P =0.000)] and it was lower in the Sham group than the I/R group (P < 0.05).Conclusion Intestinal ischemia-reperfusion can cause intestinal mucosal injury and the change of free amino acid levels in plasma and intestinal barrier damage may be related to the decline glutamine concentration and the increase of protein catabolism.
9.Application of ultrasound-guided mammotome minimally invasive surgery in breast tumor
Yukang HUANG ; Weiqiang PENG ; Chucheng WU ; Shenghong ZHANG ; Jianhua WENG ; Ning YAN ; Shaojie LIU
Chinese Journal of Primary Medicine and Pharmacy 2012;19(10):1441-1442
ObjectiveTo investigate the clinical application of ultrasound-guided mammotome surgery in breast tumor.Methods579 breast tumors from 273 patients underwent minimally invasive surgery by ultrasoundguided mammotome system.ResultsThrough 0.5cm incisal opening,all tumors were exactly,completely resected and no infaust surgery complication happened.ConclusionThe way of minimally invasive surgery of breast tumor by ultrasound-guided mammotome system was simple,precise,safe,minimally invasive and was accurate diagnosis.So popularizing this minimally invasive techniques was deserved.
10.Establishment of a sandwich ELISA method for detection of reporter chloramphenicol acetyltransferase gene.
Chen GAO ; Xingsheng HOU ; Fuping ZHANG ; Wei ZHOU ; Yukang YUAN ; Xiaoping DONG
Chinese Journal of Experimental and Clinical Virology 2002;16(1):69-73
BACKGROUNDTo establish a sandwich ELISA method for detection of reporter chloramphenicol acetyltransferase (CAT) gene.
METHODSThe full length sequence of CAT gene was amplified with PCR using plasmid pBLCAT6 as template, and inserted into the prokaryotic expression plasmid Pgex-2T. The purified fusion protein was emulsified with complete or incomplete Freund adjuvant and injected subcutaneously into rabbits. The antibody was labeled with biotin, and a sandwich ELISA technique with biotin streptavidin amplify system was established. Several CAT reporter plasmids containing different HPV 16 LCR sequences were generated and transfected transiently to monolayer cells in vitro. The cytoplasm proteins were extracted and the expressions of CAT were evaluated with the newly established ELISA assay.
RESULTSSDS-PAGE displayed that the molecular weight of the expressed fusion protein was about 54,000. The prepared antiserum was able to recognize the CAT protein expressed by mammalian cells or prokaryote cells. Under the control of different promoters and their regulate sequences,two to eight folds CAT expression increased were evaluated in transiently transfected mammalian cells by the newly established sandwich ELISA method.
CONCLUSIONSThe established method could sensitively reflect the activities of the upstream promoters, as well as the influence of exchanges of nucleotides within the regulate region on the promoter activities. Therefore, it proposes a convenient assay for the studies using CAT as the reporter gene.
Animals ; Antibodies ; analysis ; Cells, Cultured ; Chloramphenicol O-Acetyltransferase ; analysis ; genetics ; immunology ; Enzyme-Linked Immunosorbent Assay ; methods ; Genes, Reporter ; Male ; Papillomaviridae ; genetics ; Plasmids ; genetics ; Rabbits ; Recombinant Fusion Proteins ; analysis ; biosynthesis ; immunology

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