Objective To study the mutability of ultra sodium pyrosulfite intake on ultrastructure changes and spermatogonium mice testis.Methods Forty male Kunming mice were used.Experimental group had been exposed to ultra sodium pyrosulfite by fed for 10 days,and sodium pyrosulfite′s contaminated dose were 1% and 1‰.Mice were killed at 11~(th) day,and ultrastructure changes were observed under transmission electron microscopy(TEM) and the tests of sister chromosome exchanges(SCE) were made.Mmutation of ultra sodium pyrosulfite on spermatogonium of mice testis was judged.Results Compared with control group,there was a significant increase of SCE ratio in spermatogonium of testis in experimental groups(P

Objective To study the effect of hydrogen peroxide on microstructure of mice kidney and discuss the toxic effect on mice kidney.Methods Thirty healthy male mice of Kunming Genus were divided into 3 groups at random:control group and two experimental groups. Running water was fed to control group for 10 days while 0.3,3 g/L hydrogen peroxide running water readily prepared was fed to the experimental groups for 10 days. On the 10th day,the kidneys were taken out,and fixed in the fixation solutions,conventionally produced and stained.Finally,they were studied under the optical microscope.Results Experimental groups:in the kidney tissue cytoplasm of proximal convoluted tubule showed hydropic degeneration and vacuolation which depend on dose of hydrogen peroxide.Conclusion Toxic effect on mice kidney can be caused by hydrogen peroxide.

Objective To explore the effect of behavioral training on the differentiation of neural stem cells in the dental gyrus (DG) in rats with hippocampus infarction. Methods Seventy-eight Sprague-Dawley rats were randomized into infarction plus behavior training group, infarction group and control group. Photochemistry method was used to induce hippocampal infarction in rats of the infarction plus behavioral training group and infarc-tion group. At 1 day after surgery, Morris water maze training was used for infarction plus behavioral training group, free-movement without training was performed for infarction group. Double staining immunofluorescence was used to detect the co-expression of bromodeoxyuridine (BrdU) with neuronal nuclei ( NeuN ) or glia fibrillary acidic protein (GFAP) in the DG at different time points. Results Few BrdU/NeuN and BrdU/GFAP double staining cells were observed in the DG of control rats. In the infarction group and infarction plus behavioral training group the number of BrdU/NeuN and BrdU/GFAP double-stained cells increased in the DG on the opposite side compared with the control group on 14th, 21st, 28th and 35th days after surgery (P < 0.05 ). There observed significantly more BrdU/NeuN and BrdU/GFAP double-stained cells in the infarction plus behavioral training group than that in the infarction group on the 14th, 21st, 28th and 35th days after surgery ( P < 0.05 ). Conclusion Behavioral training can accelerate the differentiation of neural stem cells to neuron and astrocyte, by which to promote the re-covery of neural functions.

Humans ; Radiography ; Retroperitoneal Fibrosis ; diagnostic imaging

Probability of causation (PC) was used to facilitate the adjudication of compensation claims for cancers diagnosed following exposure to ionizing radiation. In this article, the excess cancer risk assessment models used for PC calculation are reviewed. Cancer risk transfer models between different populations, dependence of cancer risk on dose and dose rate, modification by epidemiological risk factors and application of PC are also discussed in brief.

Cell viability of Pichia pastoris was detected by flow cytometry (FCM) with two reagents fluorescein diacetate (FDA) and propidium iodide (PI). Compared with FDA/PI double-stained dot plots and PI single-stained dot plots,the latter could divide dead and living cells into two separate zones,and get the correct proportion. Then PI single-stained method was used to detect the change of cell viability in Pichia patoris fermentation. At glycerol batch and fed-batch phase,little dead cells were detected. At methanol fed-batch phase,cell viability decreased when cell weight increased,and was only 73.8% at 88 h.

Proteolytic degradation has been a severe problem when Pichia pastoris is employed to express recombinant proteins.One alternative method to circumvent this problem is to construct protease gene disruptant.However,the main study of gene disruption is focused on nonrecombinant Pichia pastoris rather than recombinant strain.In our study,we established two different methods to directly disrupt PRC1 and KEX1 gene in recombinant Pichia pastoris.On the basis of this,we further discussed and compared the application and advantages of both methods.

The kinase domain of receptor tyrosine kinase(RTK) ErbB2 was expressed fused with GFP in Pichia pastoris. Recombinant expression vector pPIC3.5K was constructed in Escherichia coli TOP10. The right P. pastoris transformants were screened on his-deficient plates and YPD-G418 plates by turns after electroporation of recombinant vector, and then induced by methanol in baffled shake bottles. The strain with highest protein yield was scaled up in a 5 L fermentor. Recombinant protein was analyzed with tyrosine kinase assay after Ni2+ affinity chromatograph. Results showed that the 100 kD recombinant protein with tyrosine kinase activity was successfully expressed in P. pastoris.

The bioreactor production of recombinant Lateolabrax japonicus growth hormone (rljGH) expressed intracellularly by Pichia pastoris was investigated. A strategy of feeding methanol at the exponential rate was established and the effect of specific growth rate on the rljGH production was examined. The results indicated that the average specific production rate increased and the rljGH production duration decreased as the specific growth rate increased. The maximum specific rljGH production (0.58 mg/g WCW) was achieved at a specific growth rate of 0.029/h. The effect of supplementing ammonium sulfate, peptone and yeast ex- tract on the rljGH production was further investigated. The results indicated that the effects of ammonium sulfate and peptone were not significant. Supplementing yeast extract of 2.5 g/L was advantageous for the rljGH production. The duration of the rljGH production was increased to 23 h from 17 h and the fermenta- tion stability of run-to-run could be improved.

A fusion expression vector pPIC3.5K-PDGFR? was constructed to express recombinant receptor tyrosine kinase PDGFR? and the right Pichia pastoris transformants were screened on his-deficient plates and YPD-G418 plates by turns after electroporation of strain GS115, a high yield strain named M3 was screened. The strain M3 was cultured in a 5 L fermentor and His-GFP-PDGFR? fusion protein was purified by Ni2+ chelating affinity chromatography. One distinct peak was obtained after elution with 250 mmol/L imidazole. Fusion protein was proved to be 90.08 kD by western blotting, and have tyrosine kinase activity by ELISA. Results showed that the receptor tyrosine kinase PDGFR? was successfully expressed in P. pastoris and could be used as a target for small molecule selective inhibitors screening.