BACKGROUND: Uncontrolled-rate freezing in -80 ℃ refrigerator is convenient, while controlled-rate freezing in -196 ℃ liquid nitrogen is reliable and long-term, the combination of the two can simplify the process and has been successfully used in clinics. OBJECTIVE: To explore the influences of different cryoprotectants by ladder-style freezing from -80 ℃ low temperature refrigerator to liquid nitrogen on the cryopreservation of hemopoietic stem cells. METHODS: The experiments were divided into four groups: 10% dimethyl sulfoxide (DMSO) group, 5% DMSO combined with 3% hydroxyethyl starch group, 5% DMSO combined with 0.25 mol/L trehalose group, 5% DMSO combined with 3% hydroxyethyl starch and 0.25 mol/L trehalose group. Peripheral hemopoietic stem cells were cryopreserved by ladder-style freezing from -80 ℃ low temperature refrigerator to liquid nitrogen. The ultrastructural changes were examined by transmission electron microscopy, the expressions of Annexin-V, PI and Caspase-3 were detected by flow cytometry. RESULTS AND CONCLUSION: There was no significant difference in survival rate, apoptotic rate and necrotic rates of the cryopreserved cells in the four groups (P > 0.05). The ultrastructural changes had no significant difference under the transmission electron microscopy. The viability was more than 90% in frozen-thawed mononuclear cell colonies, and the apoptosis was roughly 50% in the frozen-thawed CD45+ cell population, which contained many mature cells. Of hemopoietic stem cells, early stage cells have greater resistance to damage of cryopreservation than late stage cells. It is concluded that the addition of hydroxyethyl starch or trehalose into DMSO exhibits no synergistic protective effect on the cryopreservation of hemopoietic stem cells.

Objective To investigate the inhibitory effect of rhIFN-γ on human chronic myeloid leukemia cell line K562,and the impaction on the expression of CD123.Methods MTT method was used to test cell relative viability with rhIFN-γ at different concentrations.The expression of CD123 on K562 ceils was detected by flow cytometry.Results The relative inhibition of K562 cells proliferation was hampered when the cells were treated with rhIFN-γ for 72 h at the concentration of 5 x 10P ～ 108 U/L,respectively.However,rhIFN-γ at 2 x 105 U/L was benefit to K562 cells proliferation.After treatment with rhIFN-γ at 0,2 x 105 U/L and 107 U/L,the percentages of CD123 expression on K562 cells were (4.10 ± 1.46) ％,(7.2 ± 2.50) ％ as well as (21.6 ± 1.17) ％,respectively.Compared with the control group,107 U/L rhIFN-γ significantly increased the expression of CD123 on K562 cells (P＜0.05).Conclusion The effect of rhIFN-γ on the growth of K562 cells has two aspects (inhibition or proliferation),and it can increase the expression of CD 123.

Objective To investigate the changes of IL‐1β,IL‐2 ,IL‐4 ,IL‐6 ,IL‐10 and INF‐γexpressions in bone marrow of chro‐nic myeloid leukemia(CML)patients .Methods The IL‐1β,IL‐2 ,IL‐4 ,IL‐6 ,IL‐10 and INF‐γexpression levels were detected by u‐sing flow cytometry in 30 cases of CML chronic phase(CML‐CP) ,21 cases of CML accelerated phase(CML‐AP) ,15 cases of CML blastic phase(CML‐BP) ,42 cases of CML remission after treatment and 7 cases of non‐remission .Then the detection results were compared with those in the control group .Results The expression levels of INF‐γ and IL‐2 in each CML groups were lower than those in the control group(P<0 .05) ,while the expression levels of IL‐1β,IL‐4 ,IL‐6 and IL‐10 were higher than those in the con‐trol group(P<0 .05) .With the disease condition progression ,the INF‐γand IL‐2 levels were gradually decreased ,i .e .,CML‐BPCML‐AP> CML‐CP ,the difference among groups had statistical significance (P<0 .05) .After complete remission by treatment ,the INF‐γand IL‐2 levels were risen to some extent ,but which were still lower than those in the control group(P<0 .01) ,the expression levels of IL‐1β,IL‐4 ,IL‐6 and IL‐10 were decreased to some extent ,but likewise were higher than those in CML‐CP(P< 0 .05);the levels of IL‐1β,IL‐4 ,IL‐6 ,IL‐10 ,IL‐2 and INF‐γ had no statistical difference between the non‐remission group and CML‐BP group(P>0 .05) .Conclusion The changes of serum cytokines in bone marrow microenvironment of CMLpatients have certain significance to the occurrence ,development and prognosis of CML ;the de‐tection of IL‐1β,IL‐2 ,IL‐4 ,IL‐6 ,IL‐10 and INF‐γlevels in bone marrow is hopeful to provide new ideas and theoretical basis for im‐mune therapy and prognosis judgment of CML patients .

Objective To explore the role of TMAO from gut microbiota in non-alcoholic fatty liver disease(NAFLD),we detected the serum level of TMAO and its precursor metabolites in NAFLD,as well as the expression level of Eubacterium rectum,Bacteroidetes multiforme,Lactobacillus and bifidobacterium in the intestinal flora.Methods We collected 118 subjects and divided into NAFLD group(86 cases)and healthy control group(32 cases)randomly.We also detected the serum level of TMAO and its precursor metabolites in subjects by high performance liquid chromatography tandem mass spectrometry detection(LC-MS),and the expression of target bacterial DNA was detected by qRT-PCR.Results Serum TMAO,TMA and choline levels were significantly increased in NAFLD(P<0.05),and liver fat content was positively correlated with TMAO(P<0.05).The expression level of Lactobacillus and Eubacterium rectum in NAFLD group were increased(P<0.05);the expression level of Bifidobacterium and Bacteroides multiform were decreased(P<0.05).The serum TMAO level was positively correlated with Eubacterium rectum(r=0.280,P<0.05),and negatively correlated with Bifidobacterium(r=-0.332,P<0.05).Conclusion The level of TMAO in serum shows a positive correlation with NAFLD.The structure of intestinal flora in individuals with NAFLD is altered and linked to TMAO.This suggests that the intestinal flora may have a significant impact on the development of NAFLD through TMAO.

To investigate the prevalence and epidemiological characteristics of diabetic retinopathy (DR) in Yunnan Province, explore its risk factors, and provide a basis for the prevention and treatment of chronic complications of diabetes mellitus (DM). This is a large cross-sectional study, in all, 1 524 DM patients in 16 communities and villages of Yunnan Province who were registered in health service centers were included in this study from August to November 2019. All patients completed a uniform questionnaire, anthropometric measurements, biochemical measurements, and auxiliary examinations. Logistic regression analysis was used to screen the risk factors of DR. The prevalence rates of DR, mild non-proliferative DR (mild-NPDR), and referable DR (RDR) were 16.0% (244/1 524), 4.5% (69/1 524), and 11.5% (175/1 524), respectively. Glycated hemoglobin A 1c (HbA 1c)≥7.0% was the risk factor of mild-NPDR ( OR=1.872, 95% CI 1.055-3.323) and RDR ( OR=4.821, 95% CI 2.917-7.969). Blood pressure≥130/80 mmHg (1 mmHg=0.133 kPa) was the risk factor of mild-NPDR ( OR=1.933, 95% CI 1.112-3.358) and RDR ( OR=1.505, 95% CI 1.063-2.130). In Yunnan Province, 16.0% DM patients had accompanying DR, wherein about 71.7% of them required an ophthalmology referral, and the high incidence of RDR in DM patients was associated with poor control of blood glucose and blood pressure.