The efficiency comparision of continuous glucose monitoring system and blood glucose self-monitoring in evaluating blood glucose excursion in type 1 diabetes mellitus complicated with pregnancy / 中国医师进修杂志

Objective To explore the efficiency of continuous glucose monitoring system(CGMS) and blood glucose self-monitoring (SMBG)in evaluating blood glucose excursion in type 1 diabetes mellitus (T1DM) complicated with pregnancy. Methods Twenty-five patients having suffered from T1DM complicated with pregnancy were selected randomly during June 2012 to July 2015. All subjects underwent blood glucose monitoring by CGMS and SMBG for 72 h, including the data of blood glucose before meal, 2 h post-meal blood glucose (2hBG) and blood glucose at 2:00 AM. Results The level of the highest blood glucose in CGMS was significantly higher than that in SMBG:(10.60 ± 2.11) mmol/L vs. (7.50 ± 1.18) mmol/L, P0.05. The rate of hypoglycemia(blood glucose<3.3 mmol/L) in CGMS was 4.6%, and in SMBG was 1.9%. Through adjusting the treatment by CGMS, the blood glucose before meal, 2hBG and blood glucose at 2:00 AM at 49-72 h were significantly lower than that at 0-24 h (P<0.05). Conclusions Compared with SMBG, CGMS has a relatively larger blood glucose monitoring range and can sensitively evaluate blood glucose excursion, CGMS provides a scientific basis to develop a more rational and effective strategies for controlling diabetes.

High glucose impairs mitochondrial respiratory chain function in pancreatic beta cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of high glucose on mitochondrial respiratory chain function in INS-1 cells.</p><p><b>METHODS</b>The pancreatic beta cell line INS-1 was divided into the normal control (NC), high glucose (HG), and N-acetyl-L-cysteine (NAC) pretreatment groups, which were cultured for 72 h in the presence of 5.5 mmol/L glucose, 16.7 mmol/L glucose, and 16.7 mmol/L glucose with 1.0 mmol/L NAC, respectively. The activities of the enzyme complexes I and III of the respiratory chain in the cells were assessed with spectrophotometry, the ATP levels were examined using a luciferinluciferase kit, and insulin levels detected by radioimmunoassay.</p><p><b>RESULTS</b>The activities of the respiratory chain enzyme complexes I and III were 1.53-/+0.24 and 1.08-/+0.22 micromol.mg(-1).min(-1) in high glucose group, respectively, significantly lower than those in the normal control group (2.31-/+0.33 and 1.92-/+0.39 micromol.mg(-1).min(-1), P<0.01). ATP and insulin levels also decreased significantly in high glucose group as compared with those in the normal control group (P<0.01). The addition of NAC partially inhibited high glucose-induced decreases in the enzyme complex activities, ATP levels and insulin secretion (P<0.05).</p><p><b>CONCLUSION</b>The respiratory chain function is positively correlated to insulin secretion in INS-1 cells, and exposure to high glucose causes impairment of the two enzyme complexes activities through oxidative stress, resulting in the mitochondrial respiratory chain dysfunction. High glucose-induced damages of the mitochondrial respiratory chain function can be partially inhibited by NAC.</p>

Small interfering RNA-mediated islet neogenesis associated protein gene silencing inhibits the proliferation of INS-1 islet cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of small interfering RNA (siRNA)-mediated islet neogenesis associated protein (INGAP) gene silencing on the proliferation of islet cells.</p><p><b>METHODS</b>Different siRNAs targeting INGAP gene were designed and transfected into INS-1 islet cells, and the expression levels of INGAP mRNA and protein following the transfection were detected using RT-PCR, flow cytometry and Western blotting. The proliferation of the transfected INS-1 cells was evaluated using MTT assay.</p><p><b>RESULTS</b>Compared with those in the irrelevant siRNA, empty vector control, and un-transfected groups, the expression levels of INGAP mRNA and protein in the cells transfected with siRNA6 were reduced significantly. The cell proliferation rate significantly increased after transfection with siRNA6 (P<0.05).</p><p><b>CONCLUSION</b>siRNA targeting INGAP can effectively down-regulate INGAP expression and inhibit the proliferation of INS-1 cells.</p>