Trace glucose fluxes in individuals with prediabetes using stable isotopes / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The glucose fluxes of individuals with prediabetes in Chinese population are not clear. This study was to determine whether the endogenous glucose production (EGP), oral glucose rate of appearance (Ra) and glucose rate of disappearance (Rd) were different in Chinese individuals with prediabetes under fasting conditions and following an oral glucose challenge.</p><p><b>METHODS</b>Five subjects with type 2 diabetes, 5 subjects with prediabetes and 5 non-diabetic subjects matched for age, weight, fat free mass and body mass index underwent a 180 minute stable glucose isotope tracing ([6, 6-(2)H2] glucose, [1-(13)C] glucose, and [U-(13)C] glucose) study under fasting and after ingestion of a 75 g oral glucose load. Isotope glucose enrichment was measured by gas chromatography-mass spectrometry. Insulin sensitivity was estimated using the oral glucose tolerance test (OGTT)-derived insulin sensitivity index, β cell function was determined by the insulinogenic index (δI30/δG30).</p><p><b>RESULTS</b>The insulin sensitivity index (P = 0.043) and insulinogenic index (P = 0.021) were decreased in subjects with prediabetes compared with non-diabetes. Fasting EGP was slightly higher (P = 0.29) and postprandial EGP was comparable in subjects with prediabetes and non-diabetes during 120 minutes after glucose ingestion, but nadir EGP occurred later in prediabetic than non-diabetic subjects. Ra did not differ among the three groups. Rd was substantially lower in subjects with prediabetes than non-diabetes after glucose intake (P = 0.013).</p><p><b>CONCLUSION</b>The mild hyperglycemia observed among individuals with prediabetes may result from decreased Rd during the postprandial state.</p>

Approach to the male patient with parathyroid carcinoma presenting as a case of urinary tract infection / 中华内分泌代谢杂志

Parathyroid carcinoma is a rare sporadic disease.Clinical manifestations include hypercalcemia,increased urinary calcium and urinary calculus,osteoporosis,and pathologic fracture.While this patient complained of pollakiuria,urgency,and painful urination,thus might lead to misdiagnosis or missing of diagnosis of parathyroid carcinoma.This article is herewith presented to call attention to discovery,diagnosis,and treatment of parathyroid carcinoma.

Effects of advanced glycation end products on cell viability and level of reactive oxygen species(ROS)in MIN6 cells / 中华内分泌代谢杂志

To explore the effect of advanced glycation end-products(AGEs)on cell viability and level of reactive oxygen species(ROS)in MIN6 cells. After intervention of various concentrations(100,200, and 400 mg/L)of AGEs for some time, cell viability was detected by MTT assay. 2', 7'-dichlorofluorescein diacetate(DCFH-DA)was used as a reactive oxygen species capture agent. The fluorescent intensity of 2', 7'-dichlorofluorescein(DCF), which was the product of cellular oxidation of DCFH-DA, was detected by flow cytometry. The level of ROS and insulin secretion was thus measured. Viability of MIN6 cells was inhibited by AGEs in a dose and time dependent manner(P＜0.05).Intracellular fluorescent intensity of DCF was markedly elevated in the AGEs groups as compared with that in the control group(P＜0.05).Insulin secretion was decreased in the AGEs groups than that in the control group(P＞0.05). The results suggest that AGEs inhibit the viability and induce oxidative stress in MIN6 cells by overproduction of ROS.

Up-regulation of monocyte chemoattractant protein-1 in 3T3-L1 adipocytes by CoCl2 induced hypoxia / 中华内分泌代谢杂志

To investigate the effects of hypoxia chemically induced by CoCl2 on the expression of monocyte chemoattractant protein-1 ( MCP-1 ) in mouse 3T3-L1 adipocytes.3T3-L1 preadipocytes were cultured in vitro and differentiated into the matured adipocytes.Cell differentiation and lipid accumulation was determined by Oil Red O staining.CoCl2 was used as a chemical hypoxia-inducible reagent to mimic hypoxic microenvironment.The effect of CoCl2 on cell viability was estimated by MTT assay.Hypoxia-inducible factor-1α(HIF-1α) expression under hypoxia was detected by realtime fluorescent PCR and Western blot,while MCP-1 expression was detected by real-time fluorescent PCR and ELISA.CoCl2 induced hypoxia led to a marked recruitment of HIF-1α in mouse 3T3-L1adipocytes.Similarly,both mRNA and protein levels of MCP-1 were up-regulated.Exposure of 3T3-L1 adipocytes to CoCl2 induced hypoxic microenvironment in vitro,and hypoxic induction of MCP-1 expression and secretion may be mediated by HIF-1 α and may contribute to chronic low grade inflammation in adipose tissue.