1.How to Denominate "Four Pathogens and One Bacterium"
Microbiology 2008;0(12):-
Mycoplasma, Chlamydia, Rickettsia, Spirochetes and Actinobacteria were generally called "four pathogens and one bacterium". It was always difficult to be denominated and classified rightly in textbooks, while it was also a key interfering with students to grasp the concept of bacteria exactly. So we raise the question and hope to learn from each other by an exchange of views here.
2.Preparation and performance of chitosan-gelatin sponge-like wound-healing dressing
Lanzhen HE ; Yi LIU ; Dan YANG
Chinese Journal of Tissue Engineering Research 2007;11(26):5252-5256
BACKGROUND:Chitosan has good filming and viscosity, it contains free amido, and can coordinate and cross-link with gelatin, thus natural semi-interpentrating polymer network structure can be formed among molecules through hydrogen bonds.OBJECTIVE: To prepare sponge-like wound-healing dressing of good porosity, hydrophilia and air permeability by means of frozen chitosan-gelatin mixture induced phase separation.DESIGN: A comparative observation.SETTING: Laboratory of the College of Science, Guangdong Ocean University. MATERIALS: Chitosan was deacetylated by 97.55%, Mη=1.85×106; Gelatin (CP grade) was produced by Shanghai Chemical Dispensing Factory; Glacial acetic acid, NaOH, formaldehyde and glycerin were all CP grade. XL30-EDAX scanning electron microscope (Philips, Dutch); 3365-type universal material testing machine. METHODS: ① By means of frozen chitosan-gelatin mixture induced phase separation chitosan solution of 0.2, 0.4, 0.5, 0.6 and 0.8 (mass fraction) was mixed with gelatin solution, then a small amount of glycerin to prepare sponge-like wound-healing dressing of good porosity, hydrophilia and air permeability. then a small amount of glycerin, and stayed quietly to deaerate. The samples were plated with gold as routine methods, and then the surface and sectional structures were observed under the scanning electron microscope. The effects of different proportion of chitosan and gelatin on the performance parameters (water retention, moisture absorption, avulsion intensity, air permeability rate) of the sponge-like materials were observed. ② Chitosan-gelatin mixtures of 18, 20, 22, 25, 24, 26 and 28 g/L (mass fraction) were used to prepare sponge-like materials, and the effects of different contents on the performances of the materials were observed. ③ The effects of cross-linking agent (formaldehyde) of different dosages (0.002, 0.004, 0.006, 0.008, 0.010, 0.012 and 0.014 in volume fraction) on the avulsion intensity of the materials were observed.MAIN OUTCOME MEASURES: ① Surface and sectional structures of the sponge-like wound-healing dressing; ② Effects of different proportion of chitosan and gelatin on the performance parameters of the sponge-like materials; ③ Effects of different contents on the performances of the chitosan-gelatin sponge-like materials; ④ Effects of cross-linking agent of different dosages on the avulsion intensity of the materials.RESULTS: ① It could be clearly seen from the surface that the chitosan-gelatin sponge-like materials were porous structure, whereas seen from the section, the pores were honey-comb formation or three-dimensional lamellar structure accumulated by porous lamellars. ② When the content of chitosan was greater, the section looked like honey comb;Whereas as the content of chitosan decreased and gelatin content increased, the section tended to parallel lamellar structure, the water content and water retention of corresponding samples had an ascending trend, but the alvusion iintensity increased at first, and then decreased. The mass fraction of 0.5 was suitable for chitosan in the prepared solution by comprehensively analyzing the performance parameters. ③ The lower the total concentration of chitosan and gelatin, the higher the water content, the easier for the formation of bigger self-chips on the surface, the porosity of the prepared materials increased, hydrophilia and water retention ability were increased, but greater cracks formed on the material surface, and avulsion intensity was smaller. As the concentration became higher, the viscosity of the mixture became greater, the excessive viscosity was not good for mixing uniform, thus the material surface was not plain enough, and the porosity was smaller, the hydrophilia and water retention ability were relatively decreased, and the materials were harder. The total concentration should be 22-25 g/L. ④ Once the dosage of cross-linking agent was too low, very few cross-linking points generated, and the intensity was too low; Once the dosage of cross-linking agent was too high, too many cross-linking points generated, and the net space was reduced, then water content and water retention value were decreased; Whereas overdosage cross-linking agent could increase the fragility of the sponge-like materials, manifested as the decrease of avulsion intensity. When formaldehyde of 0.01 in volume fraction, the avulsion intensity was the maximal, thus the dosage of 0.01 in volume fraction was the most suitable.CONCLUSION: The main factors that affect the structures and performances of the sponge-like wound-healing dressing are the proportion of chitosan and gelatin in the mixture, total concentration of the prepared solution, amount of powder and dosage of cross-linkage agent, etc. The best matching iss chitosan of 0.05 (volume fraction)/gelatin of 0.05 (volume fraction), total mass concentration of 22-25 g/L, amount of chitosan-gelatin powder mixture is 1∶1, and the dosage of cross-linking agent is 0.01 (volume fraction).
3.The influence of the sedation based on remifentanil analgesia on the occurrence of delirium in critically ill patients
Jie LYU ; Dan LIU ; Youzhong AN ; Yi FENG
Chinese Critical Care Medicine 2015;(10):845-849
ObjectiveTo investigate the influence of the midazolam sedation based on remifentanil analgesia on the occurrence of delirium in critically ill patients in intensive care unit (ICU).Methods A single-center prospective randomized controlled trial was conducted. 140 consecutive critically ill patients admitted to ICU of Peking University People's Hospital, undergoing mechanical ventilation longer than 24 hours, with the need of sedation, from February 2014 to January 2015 were enrolled. They were randomly divided into two groups by computer generated random numbers table, eachn = 70. The patients in observation group received midazolam 1μg·kg-1·min-1 for sedation, and 1 mg/mL remifentanil for analgesia with 0.05 mg/kg intravenous bolus, then continuous infusion of 0.02-0.10 mg·kg-1·h-1. The patients in control group received midazolam for sedation only. The data were recorded as follows: the main indices for observation included the occurrence of delirium and its duration; the second item for observation was consumption of drug for sedation, followed by the mean arterial pressure (MAP) before and after sedation, the time of wake-up, duration of mechanical ventilation, the length of ICU stay, and 28-day fatality rate. The 28-day survival was analyzed by Kaplan-Meier survival curve.Results The dosage of remifentanil used in observation group was (98.6±24.9) mg/d, the dosage of midazolam was significantly lower than that of the control group (mg/d: 160.6±33.3 vs. 178.9±43.4, t = 2.829,P = 0.005), the incidence of delirium was obviously lower than that of the control group [22.9% (16/70) vs. 57.1% (40/70),χ2 = 15.700,P< 0.001], and the time of delirium was slightly shorter than that of the control group (hours: 162.9±78.0 vs. 194.8±117.3,t = 0.947,P = 0.348). Among the patients with delirium, the dosage of dexmedetomidine used in observation group was significantly less than that of the control group (mg/d: 0.54±0.11 vs. 0.64±0.14,t = 2.112,P = 0.041). The MAP before sedation was similar as the MAP after sedation in both groups, and there was no significant difference between observation group and control group [mmHg (1 mmHg = 0.133 kPa), before treatment: 84.7±16.2 vs. 89.5±37.7, after treatment: 82.3±10.7 vs. 80.8±13.9, bothP> 0.05]. There was no significant difference in the time of waking-up between observation group and control group (hours: 2.3±0.9 vs. 2.4±0.8,t = 0.487,P = 0.627). The duration of mechanical ventilation (hours: 143.4±138.3 vs. 163.9±158.9, t = 0.812,P = 0.418), the length of ICU stay (days: 8.8±7.7 vs. 10.0±7.8,t = 0.917,P = 0.361) and 28-day fatality rate [11.4% (8/70) vs. 20.0% (14/70),χ2 = 1.941,P = 0.245] in observation group were slightly lower than those of the control group without significant difference. Kaplan-Meier survival curve showed that the cumulative 28-day survival rate in observation group was slightly higher than that of control group (χ2 = 1.647,P = 0.199). ConclusionAnalgesia based on sedation may reduce the occurrence of delirium and its severity, furthermore, even if delirium occurs, it may be less severe.
4.Effects of Dexamethasone Combined with Intra-Amniotic Administration of Pulmonary Surfactant before Delivery in Preventing Neonatal Respiratory Distress Syndrome
dan, LIU ; hua, WEI ; yi-fei, ZHANG
Journal of Applied Clinical Pediatrics 2006;0(20):-
0.05),but the proportion of NRDS,the rate of mechanical ventilation dependence,and mortality had significant diffe-rences(Pa
5.Study on targets for several traditional medical formula in innate immunity against M.tuberculosis
Lixin WANG ; Dan LIU ; Yi WANG
Chinese Journal of Immunology 2000;0(09):-
Objective:To explore the potential targets for Traditional Chinese Medical Formula against tuberculosis infection.Methods:U937 cells were incubated with the drug-serum prepared with Clehnia root Ophioponis Decoction(COD),Lily Metal-Consolidating Decoction (LMCD) and Radix Ginseng Gecko Powder(RGGP) for 24 hours.The mRNA and protein level of CR1,CR3,CD14,CD43,TLR2 and TLR4 expressed in macrophages respectively were then measured by RT-PCR and FACS.The phagocytic and killing activity of the U937 cells interfered with the drug-serum for 24 h were then detected after BCG stimulation.Meanwhile,secretion of IL-10,IL-12 and the activity of iNOS in the macrophages were detected by ELISA and biochemistry method in each group.Results:The drug-serum prepared with COD,LMCD and RGGP had different regulatory effects on the expression of PRRs and the production of IL-10 and IL-12 in the macrophages,and could enhance the phagocytosis percentage and phagocytic index(P
6.Effects of Procyanidin on Myocardial Apoptosis and Related Protein Expressions in Experimental Rats With Myocardial Ischemia Reperfusion Injury
Dan LIU ; Gaopin WANG ; Qinghua CHANG ; Yi LIU
Chinese Circulation Journal 2016;31(7):696-700
Objective: To observe the effects of procyanidins on myocardial apoptosis and related protein expressions of caspase-3, Bcl-2 and Bax in experimental rats with ischemia reperfusion (I/R) injury and to explore the possible mechanism. Methods: A total of 40 male SD rats were randomly assigned to 4 groups: Sham group, IR group, Low-dose procyanidin (50 mg?kg-1) group, and High-dose procyanidin (100 mg?kg-1) group. n=10 in each group and the rats were pre-treated by intra gastric drug administration once/day for 2 weeks, then left anterior descending artery (LAD) occlusion was conducted for 30 minutes followed by reperfusion for 120 minutes to establish IR model. Blood levels of CK-MB activity and myocardial infarction (MI) size were examined; protein expressions of caspase-3, Bcl-2 and Bax were determined by Western blot analysis; myocardial apoptotic index was measured by TUNEL method. Results: Compared with Sham group, IR group presented the higher CK-MB activity, enlarged MI size, increased index of apoptosis, elevated protein expressions of caspase-3 and Bax, while reduced protein expression of Bcl-2 and the ratio of Bcl-2/Bax, P<0.05. Compared with IR group, both Low-dose and High-dose procyanidin groups had the lower CK-MB activity, smaller MI size, decreased index of apoptosis, reduced protein expressions of caspase-3 and Bax, while elevated protein expression of Bcl-2 and the ratio of Bcl-2/Bax,P<0.05. Conclusion: Procyanidin could reduce myocardial apoptosis index in experimental IR rats, which might be related to decreased protein expressions of caspase-3 and Bax, increased protein expression of Bcl-2 and the ratio of Bcl-2/Bax.
7.Efficacy observation of acupuncture and tapping therapy in the treatment of type 2 diabetes of yin deficiency pattern combined with stasis in the patients.
Yi-Dan WANG ; Zhi-Cheng LIU ; Bin XU
Chinese Acupuncture & Moxibustion 2014;34(8):731-735
OBJECTIVETo explore the clinical efficacy and mechanism of acupuncture and tapping therapy in the treatment of type 2 diabetes of yin deficiency pattern combined with stasis in the patients.
METHODSOne hundred and twelve patients were treated with acupuncture, followed by tapping method. The reinforcing method with lifting, thrusting and rotating needle technique was used at Taixi (KI 3), Shenmen (HT 7), Taibai (SP 3), Taiyuan (LU 9), Sanyinjiao (SP 6) and Zusanli (ST 36); and the even-needling technique was used at Taichong (LR 3), Hegu (LI 4), Xuehai (SP 10) and Fenglong (ST 40). The needles were remained for 30 min. After needle removal, the tapping method with plum-blossom needle was applied to Geshu (BL 17), Yishu (EX-B 3), Ganshu (BL 18), Shenshu (BL 23) and Pishu (BL 20), once every two days. The treatment of 3 months was required. The changes were observed before and after treatment in the relevant indices of fat-islet axis such as fasting plasma glucose (FPG), fasting leptin (FLP), fasting insulin (FINS), insulin sensitivity index (ISI), insulin resistance (Homa IR), insulin secretion index (Homa-beta) and the indices of obesity and blood lipids in the patients.
RESULTSAfter treatment, the total effective rate was 84.8% (95/112), in which the efficacy on the stasis predominated syndrome was better than that of yin deficiency predominated syndrome [92.9% (52/56) vs 76.8% (43/56), P < 0.05]. Before treatment, FPG, FLP, FINS, Homa-IR, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), body mass, body mass index (BMI), fat percentage (F%) and obesity degree in the patients were higher obviously than those in the normal group (all P < 0.01); high-density lipoprotein cholesterol (HDL-C) and ISI were lower than those in the normal group (both P < 0.01). After treatment, FPG, FLP, FINS, Homa-IR, TC, TG, LDL-C, body mass, BMI, F% and obesity degree were all reduced obviously as compared with those before treatment (all P < 0.01). ISI and HDL-C were increased apparently (both P < 0.01). The efficacy on mild obesity was superior to that on moderate and severe obesity, and the efficacy in the young patients was better than that in the elderly, the efficacy in the males was better than that in the females, but the differences were not significant (all P > 0.05). The efficacy in the cases with 10 years duration of sickness was superior to those with over 10 years duration of sickness (P < 0. 01).
CONCLUSIONAcupuncture and tapping therapy achieves the significant efficacy on type 2 diabetes of yin deficiency pattern combined with stasis and its effect mechanism is related to the positive regulation of glucose, lipid metabolism and fat-islet axis.
Acupuncture Points ; Acupuncture Therapy ; Adult ; Aged ; Blood Glucose ; metabolism ; Cholesterol ; metabolism ; Diabetes Mellitus, Type 2 ; metabolism ; therapy ; Female ; Humans ; Insulin ; metabolism ; Leptin ; metabolism ; Male ; Middle Aged ; Treatment Outcome ; Triglycerides ; metabolism ; Yin Deficiency ; metabolism ; therapy
9.Expression and signiifcance of thrombonspondin-1 in oxygen-induced retinopathy in mice
Guoguo YI ; Qian TAN ; Peng WANG ; Jian JIANG ; Dan LIU
Journal of Central South University(Medical Sciences) 2013;38(9):944-948
Objective:To examine the expression and function of thrombonspondin-1 (TSP-1) in oxygen-induced retinopathy in new-born mice, and to investigate its role in retinal neovascularization. Methods:A total of 40 C57BL/6J newborn mice were divided equally into a model group (n=20)andanormalcontrolgroup(n=20).Miceinthemodelgroupwereexposedto75%oxygentoestablish the oxygen-induced retinopathy (OIR) model. On the 7th, 9th, and 11th day after the birth of mice, 5 mice were randomly selected each time from the 2 groups to examine the expression of TSP-1 mRNA with reverse transcription polymerase chain reaction (RT-PCR). After that, 5 mice were selected on the 11th day to observe the retinal neovascularization by fluorescein angiography retinal flatmount. Results:On the 11th day, fluorescein angiography retinal flatmount showed that the retinal blood vessels presented mean network distribution in the normal control group, while in the model group, a lot of dilatated areas in the retinal main vessels surrounded the optic disc. Meanwhile lots of new blood vessels were found surrounding the optic disc with irregular distribution but well distributed peripherial retinal small vessels, which was typical of early stage OIR. There was no signiifcant difference in the retinal TSP-1 mRNA level between the model group and the normal control group in the postnatal 7-day mice (P>0.05). Compared with the normal control group, the expression of TSP-1 mRNA in the model group was signiifcantly lower in postnatal 9-day and 11-day mice (P<0.05, P<0.01) , and the expression of TSP-1 mRNA in postnatal 9-day mice was lower than that in the postnatal 11-day mice(P<0.05).
Conclusion:In the early stage of OIR model (retinal vascular growth and development stage), the expression of TSP-1 mRNA in the retinal tissue is gradually decreased, implying that TSP-1 (as a negative regulatory factor) may be involved in the formation of retinal neovascularization in the early stage.