MEK1 and MEK2 differentially regulate human insulin- and insulin glargine-induced human bladder cancer T24 cell proliferation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Increased risk of bladder cancer has been reported in diabetic patients. This study was to investigate the roles of mitogen-activated protein kinase kinase (MEK) 1 and 2 in the regulation of human insulin- and insulin glargine-induced proliferation of human bladder cancer T24 cells.</p><p><b>METHODS</b>In the absence or presence of a selective inhibitor for MEK1 (PD98059) or a specific siRNA for MEK2 (siMEK2), with or without addition of insulin or glargine, T24 cell proliferation was evaluated by cell counting kit (CCK)-8 assay. Protein expression of MEK2, phosphorylation of ERK1/2 and Akt was analyzed by Western blotting.</p><p><b>RESULTS</b>T24 cell proliferation was promoted by PD98059 at 5 - 20 µmol/L, inhibited by siMEK2 at 25 - 100 nmol/L. PD98059 and siMEK2 remarkably reduced phosphorylated ERK1/2. Insulin- and glargine-induced T24 cell proliferation was enhanced by PD98059, suppressed while not blocked by siMEK2. Insulin- and glargine-induced ERK1/2 activation was blocked by PD98059 or siMEK2 treatment, whereas activation of Akt was not affected.</p><p><b>CONCLUSION</b>MEK1 inhibits while MEK2 contributes to normal and human insulin- and insulin glargine-induced human bladder cancer T24 cell proliferation.</p>

Lipopolysaccharide-enhanced early proliferation of insulin secreting NIT-1 cell is associated with nuclear factor-kappaB- mediated inhibition of caspase 3 cleavage / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Increased levels of plasma lipopolysaccharide (LPS) have been found in obesity and diabetes patients. This study was to investigate the effect of LPS on pancreatic beta-cell viability and the involvement of caspase 3 in NIT-1 cell line.</p><p><b>METHODS</b>Mouse insulinoma NIT-1 cells were treated with LPS for the indicated time and dose. Cell viability was measured by cell counting kit-8 reagent. Toll-like receptor 4 (TLR4), caspase 3 and cleaved caspase 3 were detected by Western blotting. Insulin was determined by radioimmunoassay (RIA).</p><p><b>RESULTS</b>LPS promoted NIT-1 cell proliferation at 1 µg/ml, peaked at 72 hours of incubation. A reduction in cleavage of caspase 3 was observed upon LPS treatment. Bay11-7082, a specific inhibitor of nuclear factor (NF)-κB, blunted LPS-induced inhibition of caspase 3 cleavage. Reduction in chronic insulin secretion was observed after treatment with LPS at 1 µg/ml for 48 and 72 hours, not for 24 hours. TLR4 protein was upregulated when NIT-1 cells were treated with LPS at 1 µg/ml for 24 hours.</p><p><b>CONCLUSIONS</b>LPS promotes early NIT-1 cell proliferation in association with NF-κB-mediated inhibition of caspase 3 cleavage. LPS exerts a time-dependent inhibitory effect on chronic insulin secretion from NIT-1 cells.</p>

Cytogenetic and clinical analysis of 340 Chinese patients with primary amenorrhea / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To analyze the relationship between karyotypes and clinic features of patients with primary amenorrhea.</p><p><b>METHODS</b>G banding was done for 340 patients with primary amenorrhea to facilitate individual chromosome identification, and if specific staining for certain portions of the chromosome was necessary, C banding was used. The clinical data were recorded by physical examination and ultrasound scanning.</p><p><b>RESULTS</b>Karyotype analysis of the 340 patients revealed that 180 (52.94%) patients had normal female karyotypes and 160 (47.06%) patients had abnormal karyotypes. The abnormal karyotypes included abnormal X chromosome (150 patients), mosaic X-Y chromosome (4 patients), abnormal autosome (5 patients), and X-autosome translocation (1 patient). The main clinical manifestations in patients with primary amenorrhea were primordial or absent uterus (95.9%), invisible secondary sex features (68.8%), little or absent ovary (62.6%), and short stature (30.0%). The incidence of short stature in patients with X chromosome aberration (46%, 69/150) was significangly higher that in patients with 46, XX (9.44%, 17/180) as well as 46, XY (6.67%, 3/45; Chi square = 146.25, P=0.000). All primary amenorrhea patients with deletion or break-point at Xp1 1.1-11.4 were short statures.</p><p><b>CONCLUSIONS</b>One of the main reasons of primary amenorrhea is choromosome abnormality, especially heterosome abnormality. It implies the need to routinely screen chromosomal anomalies for such patients. There might be relationship between Xp1 1.1-11.4 integrity and height improvement.</p>

Effect of peroxisome proliferator-activated receptor-alpha agonist on adipokines expression in rats fed with high-fat diet / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the effect of peroxisome proliferator-activated receptor-alpha ( PPAR-alpha) agonist fenofibrate on adipokines expression in high-fat diet fed SD rats and its relationship to insulin resistance (IR).</p><p><b>METHODS</b>Rats were randomized into three groups (n = 10) : HD group, fed with high-fat diet; HDF group, fed with high fat diet and treated with fenofibrate; and control group, fed with normal diet. Animals were sacrificed after 4-week follow-up. Plasma lipids, fasting plasma insulin, free fatty acids (FFA), and insulin sensitivity were detected. Reverse transcription-polymerase chain reaction was used to semi-quantitatively determine the mRNA expression of adipokines including tumor necrosis factor-alpha (TNF-alpha) , interleukin-6 (IL-6), angiotensinogen (AGT), angiotensin 11 type 1 receptor (AT1R), and adiponectin in brown fat.</p><p><b>RESULTS</b>The plasma level of FFA, TG, and homeostatic model approach-IR index were (2. 37+/-0. 60) vs (1. 59+/-0. 30) vs (1. 33+/-0. 34 ) mmol/L, (0. 48+/-0. 11) vs (0. 30+/-0. 04) vs (0. 36+/-0. 07) mmol/L, and 12. 30+/-3. 97 vs 5. 03 +/-1. 88 vs 4. 17+/-1. 27 in the HD group, HDF group, and control group after 4 weeks of treatment with fenofibrate, respectively. The mRNA expressions of TNF-alpha and adiponectin were 1. 726+/-1. 408 vs 0. 713+/-0. 711 vs 0. 593+/-0. 382 and 0. 660+/-0. 192 vs 0. 949+/-0. 35 vs 0. 936+/-0. 130 in these three groups, which showed significant difference between HD group and HDF group (P < 0. 05 ) , while no significant difference between HDF group and control group (P > 0. 05). The mRNA expressions of AGT, AT1 R, and IL-6 had no significant difference among these three groups (P > 0. 05 ).</p><p><b>CONCLUSION</b>PPAR-alpha agonist fenofibrate may reverse high-fat diet induced lipid abnormalities, improve insulin sensitivity, and regulate the mRNA expressions of TNF-alpha and adiponectin in adipose tissues.</p>

Action of sulfonylurea on mRNA levels of components of ATP-sensitive potassium channel(SUR1,SUR2 and Kir6.2)in rat brain / 中华内分泌代谢杂志

The effects of streptozotocin-induced diabetes or long-term glyburide administration on mRNA levels of components of ATP-sensitive potassium channel(SUR1,SUR2,Kir6.2)in rat brain were observed. Streptozotocin-induced diabetes itself did not affect the mRNA levels of SUR1,SUR2,and Kir6.2 in the brain, and glyburide-treatment increased the Kir6.2 mRNA level in brain by 23% in non-diabetic rats than those in normal control but did not change SUR1 and SUR2 levels.The effects of glyburide on SUR1,SUR2 and Kit6.2 mRNA levels did not manifest in brain of diabetic rats.