Biochemistry and molecular biology is one of the most important professional basic courses for students in medical universities.Constructing scientific teaching quality control system for biochemistry and molecular biology is essential for improving its teaching quality.This paper discussed on some principles needed to be followed in constructing the teaching quality control system for biochemistry and molecular biology in medical universities and elucidated the three leveled frame of this system including university,college and department.This paper also illuminated on the main contents,implementation,organization system,evaluation system and incentive measures of this teaching quality control system.

BACKGROUND: Preparing the tracheal prosthesis by biomaterials is crucial for studying the implant of long tracheal defect.The biocompatibility and biodegradability of collagen/hydroxyapatite (Col/HAp) and poly(lactic-co-glycolic acid) (PLGA) in vivo, as a artificial material for tracheal prosthesis, need to be observed.OBJECTIVE: To explore in vivo biodegradability of Col/HAp and PLGA of tracheal prosthesis in rats.DESIGN: Randomized controlling observation.SETTING: Department of Thoracic and Cardiovascular Surgery, Clinical College of Yangzhou University; Department of Thoracic and Cardiovascular Surgery, Changzheng Hospital of the Second Military Medical University of Chinese PLA.MATERIALS: The experiment was carried out in the National Experimental Animal Center of the Second Military Medical University of Chinese PLA from March 2003 to December 2004. Sixteen SD rats of either gender were offered by this center, aged three months and weighed 150-170 g. Col/HAp and PLGA (the copolymer of polylactic acid and polyglycolic acid according to the percent of 90:10) were self-made.METHODS: ①Empirical process: Rats were fed adaptively for 1 week and anesthetized. Then undermining dissection was performed along with musculi dorsal surface toward spine bilaterally, so as to form two capsular gaps, which were implanted with Col/HAp sponge and PLGA fiber mesh cloth respectively, in a size of 10 mm ×10 mm. ②Empirical evaluation: The postoperative activity, incision healing and rejection of rats were observed; 2, 4, 6, 8 weeks postoperatively, the Col/HAp sponge and PLGA mat that were embedded subcutaneously as well as surrounding tissues were determined using scanning electron microscope or transmission electron microscope.MAIN OUTCOME MEASURES: In vivo biodegradability of two materials implanted in rats at different time points.RESULTS: ①All the animals could carry out normal activity, respiration and diet; no incision infection, fluidity, necrosis or sinus tract appeared; there was no edema in the skins of implanted area, neither hypersensitiveness nor toxicity was found; the implant materials had no rejection. ②The features of the implanted materials varied throughout the implantation. During the follow-up, the infiltration of inflammatory cells was found in the interface between the implants and neighboring host tissues in the early stage, phagocytes and fibroblastic cells were also observed later. As the process went on, the materials were biodegraded gradually, encapsulated by phagocytes, and replaced by newly generated fibrous tissues. No remarkable harmful influences of the composite materials on the neighboring host tissues such as apomorphosis, necrosis, hyperplasia and foreign body reaction were observed grossly and microscopically.CONCLUSION: All the implants show a good biocompatibility and biodegradability. Both Col/HAp and PLGA go through a gradual process of biodegradability, biological absorption and replacement by host tissues ultimately in vivo, which suggest that these two kinds of composite biomaterials will be used safely in developing tracheal prosthesis.

Objective To investigate the changes of serum osteocalcin and bone micro-structure in ovariectomized mice exposed to low-iron environment.Methods Twenty-four 12-week-old female C57BL/6 mice were divided equally into sham operation (SHAM) group,model(OVX) group,and low iron(OVX+DFO) group.In low-iron group,deferoxamine(DFO) was injected 3 times per week for 5 weeks after operation ; the other groups were injected with the same dose of 0.9％ normal saline for 5 weeks.The serum,left femur,uterus were harvested after five weeks of treatment.The serum osteocalcin and ferritin levels were measured by ELISA kit,the weight of the uterus was recorded by analytical balance.A high resolution micro-CT was used to scan the left femur for cortical bone and cancellous bone analysis.Results (1) The serum osteocalcin and serum ferritin levels in low-iron group were significantly lower than those in the other 2 groups (P＜0.01) ; (2) Compared with the sham group and ovx group,there were significant decrease of the BMD、BV/TV and Tb.N,but increase of Tb.Th and Tb.Sp in low-iron group (P＜0.01).Conclusion A certain dose of DFO (30 mg/kg) can decrease the serum ferritin levels as well as the bone formation index in ovariectomized mice.

·AIM: To investigate whether Erigeron Breviscapus (vant) Hand-Mazz (EBHM) EBHM has neuroprotective effect against N-methyl-D-aspartate (NMDA)-induced neuron death in retinal ganglion cell layer (RGCL).· METHODS: 60 healthy SD rats were randomly divided into four groups. 6 animals were normal control group (group A). The others were divided as group B (EBHM group), group C (normal saline+NMDA group) and group D (EBHM + NMDA group). Each group had 18 rats.10nmol NMDA was intravitreally injected to induce partial damage of the neurons in RGCL in the right eyes of Groups C and D. Same volume PBS was intravitreally injected into the left eyes as self-control. Groups B and D were pre-treated intraperitoneally with 6g/L EBHM solution at a dose of 150mg/kg body weight/day seven days before and after NMDA treatment. Group C were administrated intraperitoneally with 9g/L normal saline at the same time of EBHM injection. Rats were sacrificed at 4,7,14d after NMDA treatment. Flat whole retinas were stained with 5g/L cresyl violet and neuron counting in RGCL from both eyes were observed. Each subgroup had 6 rats.· RESULTS: There was no significant difference of neuron counting in RGCL between the right eye and the left eye in group A (P=0.200). There was no significant difference between normal control group and EBHM group either in the right eyes or in the left eyes at 4, 7 and 14 d respectively after intravitreal injection of 10nmol NMDA in group C and group D. (P=0.636, P=0.193). Neuron counting of RGCL in group C and D was significantly decreased in the NMDA-treated eyes at 4, 7 and 14d after intravitreal injection (P＜0.001). There was no significant difference between self-control eyes group and normai control group(P＞0.05). However, neuron counting was significantly higher in the EBHM+NMDA group than normal saline +NMDA group at 14days after intravitreal injection (P=0.044), but was lowered than normal control group (P＜0.05).· CONCLUSION: EBHM has no effect on neuron counting of RGCL when administered alone in normal rats.The results indicates that EBHM plays a partial protective role in NMDA-induced neuron loss in RGCL in the rats.

Objective To explore the mechanism underlying the induction of systemic lupus erythematosus (SLE) by estrogen, hydralazine and ultraviolet irradiation. Methods Peripheral blood mononuclear cells (PBMCs) were harvested from 10 patients with SLE and 9 normal human controls, and cultured with or without the intervention with estrogen, hydralazine or ultraviolet irradiation. The DNA methyltransferase-1 (DNMT1) activity of PBMCs was quantified by using DNMT activity/inhibition assay kit. Results No statistical difference was observed in DNMT1 activity between patients with SLE and normal controls (0.36 ± 0.24 vs 0.46 ± 0.17, P ＞ 0.05). A significant decrease was noted in DNMT1 activity in PBMCs from patients with SLE after intervention with estrogen (0.32 ± 0.18 vs 0.46 ± 0.17, t = 1.725, P ＜ 0.05), hydralazine (0.33 ±0.13 vs 0.46 ± 0.17, t = 1.739, P ＜ 0.05) and ultraviolet irradiation (0.30 ± 0.14 vs 0.46 ± 0.17, t = 1.739,P ＜ 0.05 ) compared with that from normal human controls. The treatment with hydralazine also induced an attenuation of DNMT1 activity in PBMCs from normal human controls (0.38 ± 0.12 vs 0.46 ± 0.17, P＜ 0.05).Conclusion Estrogen, hydralazine and ultraviolet irradiation can inhibit the DNMT1 activity of SLE patients,indicating that they may induce the initiation of SLE by altering the activity of DNMT1.

Objective To investigate the effects of hyperbaric oxygen preconditioning (HBOP) on brain edema, inflammatory reaction and neuronal cell apoptosis induced by experimental hemorrhage in rats. Method Eighteen male Spraque-Dawley rats, weighing 300 - 350 g,received five successive sessions of HBOP with 3 atmosphere absolute pressure and 100% O2 one hour daily for five successive days, and other eighteen rats received five successive sessions of pretreatment with one atmosphere absolute pressure, air, one hour daily for five successive days. Twenty-four hours after the final pre-conditioning, rats received an infusion of 100 μL autologous blood into the basal ganglion. Seventy-two hours later, rats were sacrificed for brain edema measurements in 12 rats of each group. The histopathological changes around the hematoma were observed microscopically, and the neuronal cell apoptosis was detected by using the terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) in six rats of each group. Data of brain water content were analyzed by using Stata 7.0 software and statistical analysis was carried out by two-tailed Student t -test. Results Compared with the control group, HBOP significantly attenuated brain edema 72 hours after intra-cerebral hemorrhage in experimental rats (81. 6± 0. 7% vs. 82. 8± 0.9%, P < 0.01). Inflammatory cell infiltration and neuronal cell apoptosis were also significantly decreased in the HBOP group. Conclusions HBOP protects the rats against brain edema formation, and quells inflammatory reaction and neuronal cell apoptosis following intra-cerebral hemorrhage in experimental rats.

Objective To investigate optimal extraction process of Piper puberulum ( Benth.) Maxim.and qualitative analyze the chemical component of the extracts.Methods Method of solvent heating reflux was used for extraction.On the basis of single factor experiment, L9 (34 ) orthogonal experiment was designed with the variants of extraction frequency, time, material-liquid ratio, and immersion time.Extraction rate as index, extraction processes were optimized to achieve best extraction.The extracts, including total extract, water elution, and ethanol elution, were physiochemically analysed to achieve an initial qualitative result.Results The optimal extraction process was: extractions 3 times for 2 hours, with an 1︰30 material -liquid ratio and 2 hours of immersion, Initial qualitative analyzed the total extracts containing amino acids, polypeptides, proteins, alkaloids, steroids or triterpenes, flavones, saponins, polysaccharides, reducing sugars or glucosides, cumarins, terpene lactones, phenols, and tannins.The water elution containing: amino acids, polypeptides, proteins, saponins, polysaccharides, reducing sugars or glucosides, cumarins, and terpene lactones.The ethanol elution containing: amino acids, polypeptides, proteins, alkaloids, steroids or triterpenes, flavones, polysaccharides, reducing sugars or glucosides, phenols, and tanins.Conclusion The experiments show that optimal extraction process can achieve high extraction yield, stable and practical.

Objective To investigate the distribution and antibiotic resistance of isolated pathogens in neonatal sepsis. Methods The results of blood culture and drug susceptibility test in neonates sepsis from January 2012 to June 2013 were retro-spectively analyzed. Results One hundred and thirty-two strains were detected in the blood samples, with 100(75.76%)Gram-positive bacteria, 30 (22.73%) Gram-negative bacteria and 2 (1.52%) fungus. Staphylococcus epidermidis, Escherichia coli and Staphylococcus aureus were the three most common pathogens. Gram-positive cocci was strongly resistant to penicillin (100.00%), erythromycin, selectrin and ampicillin/sulbactam (62.50%-100.00%), but still sensitive to vancomycin and teico-planin. The resistance rate of Gram-negative bacilli to ampicillin was 100.00%, and the resistance rate to cefatriaxone, selectrin and cefuroxime was 61.54%-100.00%. The resistance rate to imipenem and piperacillin/tazobactam was lower. Conclusions The selection of sensitive antibiotics should be based on the pathogens and drug resistance testing for the treatment of neonatal sepsis.

Objective To investigate the multidrug-resistance reversal action and mechanism of dihydroartemisin (DHA) on human colon cancer cell line HCT8/ADR. Methods The cytotoxicity of dihydroartemisin combined with doxorubicin(DOX) was determined by methyl thiazolyl tetrazolium(MTT) assay and cell apoptosis was observed by flow cytometry. Western blot assay was used to measure the autophagy. Results The combined treatment with dihydroartemisin and doxorubicin significantly enhanced the cytotoxicity in HCT8/ADR cells and effectively increased the apoptotic level. Autophagy was also induced by the combined treatment , which maybe played a crucial role in the regulation of doxorubicin-sensitization of HCT8/ADR cells. Conclusion The results indicated that dihydroartemisin can reverse multidrug resistance through increasing the doxorubicin-sensitivity of HCT8/ADR cells.

Background and purpose: Lysine specific demethylase 1(LSD1) is an important chromatin modifier. It epigenetically regulates gene expression pattern through chromatin modification and participates in maintenance of tumor malignant properties, such as oncogenesis, development, invasion, migration and metabolic transformation. SIRT3 (sirtuin 3) is a mitochondria localized tumor suppressor and regulates tumor metabolic transformation and oxidative stress. The correlation between LSD1 and SIRT3 has never been reported before. This study aimed to elucidate the correlation between LSD1 and SIRT3 with gene transcriptional regulation methods. Methods: RNA interference technique, co-immunoprecipitation assay(CoIP), chromatin immune-precipitation assay(ChIP) and ifrelfy luciferase activity assay were employed to elucidate the correlation between LSD1 and SIRT3 in pancreatic cancer. Results:mRNA and protein levels of SIRT3 were signiifcantly elevated in LSD1 knock-down PANC-1 cells. LSD1 interacts with PGC-1α, an important regulator of SIRT3 gene expression. LSD1 and PGC-1αoccupied the same region in SIRT3 promoter region through ChIP analysis. Luciferase activity assay validated LSD1 as a negative regulator of PGC-1αin SIRT3 gene transcriptional regulation. Conclusion:LSD1, as an important tumor promoter, negatively regulates the expression of tumor suppressor gene SIRT3, these results provide important clues for the role that LSD1 plays in aberrant metabolism and oxidative stress.