A versatile role of transcription regulator CTCF in epigenetics and diseases / 中华医学遗传学杂志

CTCF as a multivalent eukaryotic transcription factor plays a diverse range of roles in regulation of various genes through the binding of its 11 zinc fingers to CTCF consensus sites or various proteins. CTCF is involved in multiple aspects of epigenetic regulation including regulation of chromatin remodeling and genomic imprinting. Deregulation of these processes result in a group of diseases are characterized by growth, development, and neurological dysfunction. This paper reviews recent researches that highlight the links between CTCF, epigenetics and diseases.

Short-term central nervous system symptoms and changes in blood indicators after benzene poisoning in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the central nervous system symptoms and alterations in the blood indicators in rats within a short term after benzene poisoning.</p><p><b>METHOD</b>Twenty-four female SD rats were randomized into 4 equal groups to receive intraperitoneal injection of low-, medium- or high-dose benzene (39.05, 78.11, and 234.33 mg/kg, respectively) or peanut oil. Blood samples were taken from the rats via the femoral artery 24 h after the injections for routine blood test and liver and kidney function test.</p><p><b>RESULTS</b>Intraperitoneal injection of benzene at a high dose, but not at a low or medium dose, caused obvious symptoms in the central nervous system. Benzene either at a low or medium dose did not produce obvious changes in routine blood test or liver and kidney function test as compared with the control group, but a high dose resulted in significant changes in WBC, PLT, ALT and AST (P<0.05). Abnormalities in the renal function were found in none of the groups (P>0.05).</p><p><b>CONCLUSION</b>Exposure to high-dose benzene can result in abnormalities in the central nervous system, routine blood indicators and liver function, but does not obviously affect the kidney function in rats.</p>

Influence of nm23-H1 gene silence in K562 cell on its differentiation toward megakaryocyte / 中华血液学杂志

<p><b>OBJECTIVE</b>To construct a stable nm23-H1-knock-down cell model with K562 cell line and study its differentiation toward megakaryocyte.</p><p><b>METHODS</b>Eukaryotic expression vector pSilencer 4.1-CMV-sinm23 expressing siRNA targeting nm23-H1 was transfected into K562 cells with lipofectamine2000. Cells with stably nm23-H1 silence were screened out by G418. Real-time quantitative PCR, immunocytochemistry, western blot were used to confirm the nm23-H1-knock-down K562 model. Cell differentiation capacity was detected by NBT reduction assay. Surface antigen Gp IIb-IIIa (CD41) of knock-down cells treated with phorbol 12-myristate 13-acetate was analyzed by flow cytometry. Western blot was used to detect the ERK1/2 signal pathway after the stimulation of phorbol 12-myristate 13-acetate.</p><p><b>RESULTS</b>Endogenous nm23-H1 was silenced by pSilencer 4.1-CMV-sinm23 and the silence efficiency was up to 75% and 70% in mRNA and protein levels respectively compared with the mock cells. Under phorbol 12-myristate 13-acetate treatment, the knock-down cells displayed a significantly increased differentiation ability toward megakaryocyte compared with control. The NBT reduction values were (0.31 +/- 0.07) and (0.23 +/- 0.05) respectively. Further results revealed that nm23-H1 gene regulating the megakaryocytic differentiation was due in part to the increased ERK1/2 phosphorylation.</p><p><b>CONCLUSIONS</b>A stable nm23-H1-knock-down K562 cell model is successfully constructed. nm23-H1 involves in regulating the megakaryocytic differentiation of K562 cell line.</p>

Effects of Sargassum confusum polysaccharide on the expression of p53 and Rb genes in mouse sarcoma S180 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate effects of Sargassum confusum polysaccharide (SP) on the expressions of p53 and Rb genes.</p><p><b>METHODS</b>The mice bearing S180 sarcoma were treated with abdominal SP injection at the daily dose of 50, 100 or 200 mg/kg for 10 consecutive days, The mice injected with 0.85% saline served as the negative control group and those with 5-fluorouracil (5-FU) injection as the positive control group. The tumor weight was measured to calculate the tumor inhibition rate. RT-PCR and Western blotting were used to detect the expression levels of p53 and Rb genes at the mRNA and protein levels, respectively.</p><p><b>RESULTS</b>The 10-day SP treatment at 50, 100 and 200 mg/kg resulted in tumor growth inhibition rates of 30.5%, 47.6% and 63.5%, respectively. SP treatment upregulated the mRNA expressions and increased the protein levels of p53 and Rb in the tumors.</p><p><b>CONCLUSION</b>SP has inhibitory effect against S180 sarcoma in vivo and can increase the expression levels of p53 and Rb genes at both the mRNA and protein levels.</p>

Beneficial effects of a diabetes specific formula on insulin sensitivity and free fatty acid in patients with type 2 diabetes mellitus / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>This prospective, randomized, controlled study was designed to investigate the effects of a diabetes specific formula (Diason low energy: 313.8 kJ/100 ml), compared with a standard formula, on insulin sensitivity, serum C peptide, serum lipids and free fatty acid (FFA) in type 2 diabetics.</p><p><b>METHODS</b>In total of 71 type 2 diabetics completed the study. Enteral formulas were given orally as the sole source of nutrition to the subjects for 6 days. Venous blood samples (0.5, 1, 2, 3 hours) were collected at day-7 after a 75 g oral glucose tolerance test (OGTT), day 1 after a standard test meal (1673.6 kJ) and after 6 days of either the test diabetes specific formula or a standard formula. Plasma glucose, serum insulin, C peptide and lipids were measured.</p><p><b>RESULTS</b>After the intervention period, the diabetes specific formula resulted in a significantly lower postprandial rise in blood glucose concentrations at 0.5 hour (P < 0.05) and 1 hour (P < 0.01); significantly lower peak height of plasma glucose (P = 0.05); significantly lower plasma insulin concentrations at 0.5 hour (P < 0.01), 1 hour (P < 0.01) and 2 hours (P < 0.01); and a significantly lower plasma insulin peak compared to controls; both OGTT and a standard test meal (P < 0.05). The glucose and insulin area under the curve after the diabetes specific formula compared to the standard formula were significantly lower. The C peptide level was lower after 6 days of both nutrition formulas compare to 75 g OGTT, but not different from the standard mixed meal. Both formulas were well tolerated.</p><p><b>CONCLUSIONS</b>In summary the diabetes specific formula with a relatively high monounsaturated fatty acid and high multi fiber proportion significantly improved glycemic control. On top of this, the insulin sensitivity (HOMA-IS) was significantly improved and may therefore directly improve the impact on long term complications. The disease specific formula should therefore be the preferred option to be used by diabetic and hyperglycemic patients in need of nutritional support.</p>

Association between A1168C polymorphism in PAX4 gene and type 1 diabetes in Han Chinese / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore whether A1168C polymorphisms in paired box gene 4 (PAX4) are associated with type 1 diabetes mellitus (T1DM) in Chinese Han population.</p><p><b>METHODS</b>Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to genotype A1168C polymorphisms in PAX4 gene. Totally 109 patients with T1DM and 251 control subjects were recruited. The frequency distributions of genotypes between two groups were analyzed by SPSS software.</p><p><b>RESULTS</b>The genotype distributions were in Hardy-Weinberg equilibrium both among T1DM cases and control subjects. No difference was observed in the genotype frequencies and allele frequencies between T1DM cases and control subjects (P > 0.05), nor was any disease association detected when patients were stratified according to age at diagnosis or sex (P > 0.05).</p><p><b>CONCLUSION</b>The A1168C single nucleotide polymorphism in PAX4 gene may not play an essential role in genetic T1DM susceptibility in Chinese Han population.</p>

Efficient purification of recombinant human NDPK-A in pilot-scale / 生物工程学报

To purify recombinant human nucleoside diphosphate kinase A (rhNDPK-A) efficiently in pilot scale, cells of rhNDPK-A producing E. coli were homogenized by high pressure under 4 degrees C, 950 Pa. The insoluble debris was removed by microfiltration and the soluble portion was concentrated by ultrafiltration. The resulted crude sample was loaded on DEAE-sepharose Fast Flow. The target fraction was collected and then load on Cibacron Blue 3GA Sepharose CL-4B. Eluted with buffer containing ATP from the AC column, rhNDPK-A was polished with ultrafiltration. The results showed that after homogenized 2 rounds, 1500g cells of E. coli brought crude sample containing 47.6g NDPK-A. Treated with microfiltration and ultrafiltration, 27.3g of NDPK-A were recovered from this bacteria homogenate. After 2-step purification with column chromatography and then polished with ultrafiltration, 17.2 g rhNDPK-A were collected with purity of 96.3%. The recovery of the whole purification process was 36.2%, and the productivity of rhNDPK-A was 1.15 g per 100 g wet cells. Comparing the recovery of each purification step, it was found that the recovery of polish is higher than that of affinity chromatography, which is higher than that of ion exchange chromatography. The limit step was the process of sample pretreatment among the 4 purification steps. Combine with the fermentation results reported before, it was deduced that the productivity of rhNDPK-A was 510 mg/L. In conclusion, an easily controlled purification condition with high yield provides material for the translation researches of NDPK; In addition, it was suggested the crucial step determine the recovery of non-secretive recombinant proteins might be the process of sample pretreatment, not be the process of column chromatography.

Silencing HSV1 gD expression in cultured cells by RNA interference / 病毒学报

To explore the anti-HSV-1 effect of silencing gD gene expression by RNA interference, five 21-nucleotide duplex small interfering RNAs(siRNAs) targeting the HSV1 gD sequence were designed and the gD-EGFP fusion gene expression vector was constructed, then co-transfected into Vero cell, and screened the effective siRNA through analyzing the intensity of the EGFP fluorescence. Finally, the anti-HSV1 effect was confirmed by plaque reduction assay, real-time PCR and daughter virus titration of HSV1 infected Vero cells transfected with siRNAs. The study demonstrated that siRNAs could effectively and specifically inhibit gD gene expression in HSV1-infected cells, but only had a little effect on HSV1 infection, so taking gD as the target of siRNA against HSV1 needs further study.

Immune Responses and Histopathological Changes in Rabbits Immunized with Inactivated SARS Coronavirus / 中国病毒学

To evaluate the immunogenicity of inactivated SARS coronavirus (SARS-CoV), three groups of rabbits were immunized three times at 2-week intervals with inactivated vaccine + adjuvant, adjuvant,and normal saline respectively. Eight batchs of serum were sampled from the auricular vein at day 7 to day 51, and specific IgG antibody titers and neutralizing antibody titers were detected by indirect ELISA and micro-cytopathic effect neutralizing test. Antibody specificity was identified by proteinchip assay.Histopathological changes were detected by H&E staining. The results showed that, rabbits in the experimental group immunized with inactivated SARS-CoV all generated specific IgG antibodies with neutralizing activity, which suggested the inactivated SARS-CoV could preserve its antigenicity well and elicit an effective humoral immune responses. The peak titer value of specific IgG antibody and neutralizing antibody reached 1:40960 and 1:2560 respectively. In the experimental group, no obvious histopathological changes was detected in the H&E stained slides of heart, spleen, kidney and testis samples, but the livers had slight histopathological changes, and the lungs presented remarkable histopathological changes. These findings are of importance for SARS-CoV inactivated vaccine development.

Effects of vitamin D receptor gene polymorphisms on susceptibility to type 1 diabetes mellitus / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the influence of vitamin D receptor (VDR) gene polymorphisms on susceptibility to type 1 diabetes mellitus (T1DM) in the Chinese Han population.</p><p><b>METHOD</b>One hundred and thirty-six Chinese Han people, including 54 T1DM patients and 82 unrelated healthy subjects as control were genotyped by polymerase chain reaction-restriction fragment length polymorphism for three restriction sites in the VDR gene, which were ApaI, TaqI, and BamI.</p><p><b>RESULTS</b>The frequency of B allele of BsmI site in VDR gene was significantly higher in T1DM patients than in healthy subjects (P = 0.033) while no difference was found between the two groups in the distribution of ApaI and TaqI polymorphisms.</p><p><b>CONCLUSION</b>The BsmI polymorphism of VDR gene may be associated with the susceptibility to T1DM in the Chinese Han population of Beijing.</p>

Effects of 75 gram glucose oral tolerance test and standard meal test on insulin secretion function of islets of Langerhans and free fatty acid in patients with type 2 diabetes mellitus / 中华全科医师杂志

Objective To observe the effects of 75 gram glucose oral tolerance test (75 g OGTT) and standard mixed meal test (SMMT) on insulin secretion function of the islets of Langerhans and plasma free fatty acid (FFA) in patients with type 2 diabetes mellitus.Methods Seventy-six patients with type 2 diabetes without using insulin and with no obvious complications were recruited for 75 g OGTT following overnight fasting on the first day and SMMT (bread 50 g,egg 50 g and milk 250 ml) on the 7th day.Blood specimens were collected from each patients before the tests and 30 min,60 min,120 min and 180 min after glucose or meal load to measure their levels of plasma glucose,serum insulin,C peptide,FFA and lipids (total cholesterol,triglyceride,high-density and low-density lipoprotein cholesterol).Results No difference in fasting plasma glucose,serum insulin,C peptide,FFA and lipids between 75 g OGTT and SMMT was found.Postprandial plasma glucose 30 min,60 min,120 min and 180 min after 75 g OGTT was significantly higher than that after SMMT,with (15.3?3.5) vs (9.9?3.4) mmol/L,(18.2?4.8) vs (12.8?4.0) mmol/L,(16.3?5.8) vs (12.2?4.9) mmol/L and (10.6?5.4) vs (9.5?4.5) mmol/L (F=28.1,P