Objective To evaluate the effect and significance of PBL in clinical skills experiment teaching center (CSETC). Methods A total of 60 undergraduates in major of clinical medicine were divided into two groups according to their student ID. The control group (n=30) was set in an ordinary small classroom, while the experimental group (n=30) was in CSETC for fully using the teaching resources there. Both groups were taught with PBL method by same teachers, and the integrated final examination and questionnaire were adopted to evaluate the teaching effect. SPSS was used for statistical analysis. Results All 8 participated teachers believed that carrying out PBL in CSETC could promote teachers’ professional development, alleviate the shortage of teachers and classroom, increase the utilization ratio of CSETC, and improve the teaching quality. The results of survey on students showed that, compared with the control group, information management ability and clinical skills of students were improved obviously (Plt;0.01). Although there was no difference in total score of final exam, the experimental group was markedly higher than the control group in the score of clinical skill subject (Plt;0.01). Conclusion Carrying out PBL in CSETC can improve teaching quality, and clinical skills and information management ability of students. It is helpful to alleviate the shortage of teachers and classroom, and promote the teaching standards of CSETC.
Objective To discuss the methods of producing experimental models of chronic pancreatitis and their individual properties. Methods The recent literatures about experimental models of chronic pancreatitis were reviewed and analyzed. Methods of producing experimental models and their individual properties were summarized, and best models suitable for varied chronic pancreatitis were afforded. Results Diet, ligation of pancreatic duct, caerulein, dibutyltin dichloride (DBTC), arterial ligation, injecting microspheres into artery, and injection of pancreatic duct could induce different experimental models of chronic pancreatitis. Spontaneous chronic pancreatitis was induced by diet, chronic obstructive pancreatitis produced by ligation and injection of pancreatic duct, chronic relapsing pancreatitis evoked by caerulein, and chronic active pancreatitis made by arterial ligation and injecting microspheres into artery.Conclusion Different methods could induce models of chronic pancreatitis, which had their individual properties.
ObjectiveTo investigate the possible mechanism affecting liver cirrhosis by splenectomy. MethodsBy subcutaneous administration of 20% carbon tetrachloride(CCl4), liver cirrhosis models were established in splenectomy and nonsplenectomy groups. After HE staining, special staining and immunohistochemical staining, mast cell, Kupffer’s cell and Ito cell were counted under optical microscope. Liver pathological sections and the dynamic changes of these cells in mice were studied respectively in comparison with the normal group.ResultsThe incidence of liver cirrhosis in nonsplenectomy group was significantly higher than that in splenectomy group after the 16th injection of CCl4 (P＜0.05). The count of mast cell was much higher than that in splenectomy group after the 4th and the 8th injection (P＜0.05). Kupffer’s cell and Ito cell significantly increased after the 12th and the 16th injection in nonsplenectomy group compared with splenectomy group (P＜0.05). ConclusionSplenectomy may decline the incidence of hepatic cirrhosis caused by multifactors. In the early stage, splenectomy influences the migration, maturation and accumulation of mast cell. In the middle and late stage, it influences the proliferation of Kupper’s cell and cytokine secretion, thus the Ito cells are activated and proliferation is inhibited, in which extracellular matrix decreases in amount and the degree of hepatic fibrosis is reduced.
ObjectiveTherapeutical effect of recombinant human growth hormone （rhGH) on obstructive jaundice and internal and external drainage was observed.MethodsNew Zealand white rabbits were randomly divided into groups below: obstructive jaundice internal drainage plus rhGH group, obstructive jaundice internal drainage plus NS group, obstructive jaundice external drainage plus NS group, and obstructive jaundice external drainage plus rhGH group. After the establishment of obstructive jaundice model, rhGH was used in the above groups. Subcutaneous injection of rhGH 0.2 IU/kg was given twice a day. Isovolume NS was used on the control groups. Full set of endotoxin, tumor necrosis factor, sIL2R and nutritional status were estimated before the model establishment, and 14 days after the model established, 14 days after internal and external drainage.ResultsFour days after internal and external drainage, body weight of therapy groups was increased compared with control groups (P＜0.05). Seven days and ten days after obstructive jaundice, blood sugar of therapy groups rised compared with control groups (P＜0.05). Albuminate, siderophilin and prealbumin of therapy groups were all observed an increase after 14 days after obstructive jaundice, and 14 days after internal and external drainage (P＜0.01). Blood total cholesterol, low density lipoprotein and omni bile acid of therapy groups after 14 days of obstructive jaundice were increased apparently (P＜0.05). Blood glutamicoxal acetic transaminase, transglutaminase, total bilirubin, blood uria nitrogen, creatinine and uric acid of therapy group after 14 obstructive jaundice days were increased (P＜0.05). Ca2+ of therapy groups 14 days after obstructive jaundice, 14 days after internal and external drainage rised as compared with control groups (P＜0.05). However, K+,Na+ of therapy groups 14 days after external drainage decreased (P＜0.05). An increasing tendency of sIL2R was observed in control groups 14 days after obstructive jaundice(P＜0.05) and ET,αTNF,sIL2R of control groups was decreased 14 days after internal and external drainage (P＜0.01).ConclusionAfter rhGH is used in obstructive jaundice and internal and external drainage, an improvement of nutritional status and immunological function can be observed.
【Abstract】Objective To investigate the inhibitory effects of flavonoids quercetin on the occurrence and proliferation of experimental mammary carcinoma. Methods DMBA induced mammary carcinoma was produced in rats. Seventy-nine female Sprague-Dawly rats were divided randomly into four groups: DMBA, DMBA with TAM, DMBA with quercetin and control. Chemicals had been administered to group A, group B, group C and group D respectively for 28 weeks. Samples of breasts were collected for light microscope observation and electromicroscope observation. Their expressions of proliferating cell nuclear antigen (PCNA) and the protein product of H-ras were examined by immunohistochemical staining. Results ①Mammary carcinoma incidence of group A(76.2%) was significantly higher than that of group B(40.9%), group C(45.5%) and group D(0%),P＜0.05, and there was no significant difference between group B and group C (P＞0.05), which indicated that quercetin could inhibit the occurrence of mammary carcinoma. ②Mean mammary tumor diameter of group A (2.37cm) was significantly larger than that of group B(1.82cm) and group C(1.71cm), P＜0.05, and there was no significant difference between group B and group C (P＞0.05), which indicated that quercetin could inhibit the growth of experimental mammary carcinoma. ③Immunohistochemical staining of PCNA showed significant difference between group A and group B, group A and group C (P＜0.05), with no significant difference between group B and group C (P＞0.05), which indicated that quercetin could inhibit the proliferation rate of tumor cells. ④Significant difference between group A and group B, group A and group C (P＜0.05), and no significant difference between group B and group C (P＞0.05), were noticed with immunohistochemical staining of H-ras protein product, which indicated that quercetin could inhibit the activity of Hras protein. Conclusion Quercetin could reduce the mammary carcinoma incidence and its degree of growth, and it may be related with its inhibitory effect on the activity of Hras and the proliferation of tumor cell.
To observe the changes of intestinal bacteriology in acute necrotizing pancreatitis (ANP). Dog ANP model was induced by injection of sodium taurocholate with trypin into the pancreatic duct. All dogs were sacrificed on the seventh postoperative day, mucosal and luminal microflora of intestine were analyzed quantitatively. The blood and organs were collected for culture. The results showed that population levels of E.coli in the intestinal mucosa and the content in cecum of the ANP dogs showed much higher level than those of the controls (Ｐ＜0.01 or Ｐ＜0.05), while bifidobacterium and lactobacillus were decreased significantly (Ｐ＜0.01), resulting in reversal of bifidobacterium/E.coli ratio. Blood levels of endotoxin were 1-2 times higher in ANP group as compare with the controls. The positive rate of blood and organs were 100% in ANP dogs. E.coli were the major bacteria cultured. The results indicated that microecological disturbance could take place after the onset of ANP, which may take an important role on pancreatic infection complicating ANP.
To introduce a rat model of the conversion of acute edematous pancreatitis (AEP) to necrotizing pancreatitis (ANP). One hundred and seven Sprague-Dawley rats were randomized in three experimental groups as follows: sham operation control group and AEP group and ANP group. AEP was induced by pancreatic duct ligation and exocrine stimulation, ANP was induced same as AEP，but with a large dose of dextran-110 (500mg/kg) intravenously. The serum concentration of amylase increased significantly in AEP group and ANP group. Cytosolic free Ca2+ concentration in isolated pancreatic acinar cells increased consistently after induction of ANP. Homorrhage, parenchymal necrosis and calcium deposits in acinar cells were observed in pancreas in ANP group. Ultrastructural examination showed desquamation and necrosis of the endothelium of the pancreatic capillary in ANP group. These results suggest that ischemia may induce the conversion of AEP to ANP via acinar cell Ca2+ overloading. The rat model would seem to be a suitable animal model for studying aggravating mechanism of acute pancreatitis.
Objective To study the pathology and possible mechanism of experimental hydrochloric acid（HCl） inhalation-indued pulmonary fibrosis in rats.Methods 120 male SD rats were randomly divided into a nomal control group，a bleomycin group，a high dose HCl group，a middle dose HCl group and a low dose HCl group.The bleomycin group was intratracheally injected with bleomycin once to induce pulmonary fibrosis.The three HCl groups were intratracheally injected with HCl once per week.The control group was given saline by the same way.Six rats of each group were randomly sacrificed on day 7，14，28 and 42 respectively.The histological changes of lung tissue were studied by HE and Masson’s trichrome staining.Hydroxyproline level in lung tissue was measured by digestion method.Protein and mRNA expression of transforming growth factor-β1（TGF-β1） were assayed by immunohistochemistry and RT-PCR respectively.Results Alveolitis in three HCl groups was significantl compared to control group，most severe at the second week，then remained at a high level which was equivalent to or exceeded the level of the bleomysin group after 28 days.Pulmonary fibrosis in three HCl groups was also significantly more severe than that in the control group，but milder than that in the bleomysin group.The high-dose and middle-dose HCl groups were not significantly different from the bleomysin group on day 42.There was no difference between three HCl groups in the earlier period，but the high-dose HCl group has a significantly difference from low-dose group on day 42.The content of hydroxyproline in high-dose and middle-dose HCl groups was also significantly higher than that in the control group.On day 42 hydroxyproline content in high-dose HCl dose rather middle –or low dose group was similiar with the level of bleomysin group.Content of TGF-β1 mRNA in three HCl groups was comparable to the level of bleomysin group on day 28 and exceeded on day 42.The expression of TGF-β1 in three HCl groups was not significantly different from the bleomysin group on day 42.Conclusion Experimental acid aspiration might contribute to pulmonary fibrosis in rats.Acid induced alveolar epithelial cell damage，abnormal proliferation and repair and fibrosis could be involved..
Objective To explore the effects of mechanical stretch with variant frequencies on the alignment and differentiation of the multilayer myotubes cultured in vitro, and to select the optimized cultural condition of regenerative skeletal muscle tissue with stress loading cultured in vitro. Methods C2C12 myoblasts cultured in vitro in the groove casts of Sylgard 184 were induced into the multilayer myotubes. Meanwhile the myoblasts were treated with various mechanical stretch withcells tensile instrument, at the amplitude of 10% and the frequency of 0 (group A), 0.25 (group B), 0.50 (group C), and 1.00 Hz (group D) for 1 hour, 3 times a day. The myotubes morphology was observed by inverted phase contrast microscope at 5, 7, and 10 days after continuous mechanical stretch. And the expressions of mRNA for myogenic differentiation antigen (MyoD), Myogenin, Desmin, and myosin heavy chain (MyHC) were detected by RT-PCR and real-time fluorescent quantitative PCR (QRT-PCR), respectively. Results The mechanical stretch could promote the al igned fusion and increase the number of myotubes. Indeed the multilayer myotubes arranged more closely in group B at 7 days. At the same group, as the time went on, the mRNA expressions of MyoD gradually decl ined in each group. There were significant differences in mRNA expressions of MyoD between 5 days and 7, 10 days (P lt; 0.05). The mRNA expressions of Myogenin, Desmin, and MyHC were highest at 7 days. There were significant differences between different time points (P lt; 0.05), except the mRNA expression of Desmin of group B between 7 and 10 days (P gt; 0.05). At the same time, with the increase of frequency, the highest mRNA expressions of MyoD, Myogenin, Desmin, and MyHC were in group B. There were significant differences at the same time between group B and the other groups (P lt; 0.05), except mRNA expression of Desmin at 5 days between groups B and C, and mRNA expression of MyHC at 10 days between groups A and B (P gt; 0.05). Conclusion Low frequency (0.25 Hz) and suitable time (7 days) periodic mechanical stretch is beneficial to the differentiation of the multilayer myotubes cultured in the groove casts of Sylgard 184, but as the stretch time goes on the aging of myotubes will be accelerated.
Objective As a bioactive material, the osteogenic activity of borate bioglass has been proved. To design a novel borate bioglass according to an improved formula and to investigate the effects of the borate bioglass on osteoblasts invitro for further research and potential cl inical appl ication. Methods The novel Na2O-K2O-MgO-CaO-P2O5-B2O3-SrO borate bioglass was prepared by melting process. The initial and secondary extracts were prepared according to ISO10993-12: 2007 respectively with different extract time of 0-24 hours and 24-48 hours. The osteoblasts (MC3T3-E1) of the 5th-15th passages from mouse were cocultured with the initial (initial extract group) and secondary (secondary extract group) extracts, respectively, to assess the effects of the borate bioglass on the cell prol iferation, protein synthesis, alkal ine phosphatase (ALP) activity, cell apoptosis, and cell migration; while α-MEM medium without addition of extract served as control group. Results The absorbance values at 450 nm were 0.356 0 ± 0.018 7, 0.331 0 ± 0.025 4, and 0.204 0 ± 0.013 8 in initial extract, secondary extract, and control groups, respectively, showing significant differences among 3 groups (P lt; 0.05). The total protein contents were (382.847 ± 9.521), (226.071 ± 5.847), and (220.248 ± 8.213) U in initial extract, secondary extract, and control groups, respectively; there were significant differences between initial extract group and control group, and between initial extract group and secondary group (P lt; 0.05), but there was no significant difference between secondary extract group and control group (P gt; 0.05). However, no significant difference was observed in the ALP activity [(0.013 01 ± 0.000 39), (0.012 93 ± 0.000 44), and (0.012 92 ± 0.000 35) U/ mg], apoptosis rate (7.03% ± 1.95%, 6.46% ± 2.88%, and 6.18% ± 2.21%), horizontal migration [(137.50 ± 11.43), (134.98 ± 10.50), (135.21 ± 8.66) μm], and transmembrane cell number [(10.92 ± 4.99), (10.07 ± 2.50), and (9.81 ± 2.64) cells/ field] among initial extract, secondary extract, and control groups (P gt; 0.05). Conclusion This novel borate bioglass has excellent cytocompatibil ity, which plays regulatory effects on the cell prol iferation, secretion, and migration.