Study on Residual Stress in Disc-Milling Grooving of Blisks.

The disc-milling method is expected to increase the grooving efficiency of blisks. However, there are few studies about the residual stress on a blisk during disc-milling grooving. In this study, a single-factor experiment and an orthogonal experiment of blisk disc-milling and grooving were designed to obtain the residual stress. Surface subsurface residual stress were also studied. The results showed that the surface of the milling groove bore compressive stress. Residual stress decreased with increasing spindle speed and increased with increasing feed speed and spindle rotation angle. Moreover, residual stress was most sensitive to spindle rotation angle and least sensitive to feed speed. A higher residual stress produced on the machined surface led to a deeper layer of residual stress.

Comparison of Clinical Efficacy and Safety between Misoprostol and Oxytocin in the Prevention of Postpartum Hemorrhage: A Meta-Analysis.

In order to systematically evaluate the clinical efficacy and safety of misoprostol versus oxytocin in the prevention of postpartum hemorrhage, this paper provides evidence-based reference for clinical medication, computerized retrieval of Chinese biomedical literature database (CBM), PubMed, Embase, Cochrane Library, and clinical trials. The retrieval period is from the establishment of each database to October 1, 2021. Published randomized controlled trials (RCTS) are included in this study. The literature is screened and evaluated according to inclusion and exclusion criteria, and meta-analysis is performed using RevMan 5.3 software. A total of 13 RCTS are included, with a total of 24754 parturients. The meta-analysis shows the average blood loss (SMD = 0.10, 95% CI (-0.11, 0.32), P=0.35), the time of the third stage of labor (SMD = 0, 95% CI (-0.07, 0.08), P=0.95), and blood transfusion rate (RR = 0.80, 95% CI (0.63, 1.02), P=0.07). However, the incidences of shivering (RR = 2.61, 95% CI (1.79, 0.81), P < 0.00001) and vomiting (RR = 2.78, 95% CI (1.85, 4.18), P < 0.00001) are significantly higher than those in oxytocin group. The effect of misoprostol on preventing postpartum hemorrhage is similar to that of oxytocin, but the incidence of adverse reactions is high, and the occurrence of adverse reactions should be closely watched in the use process. Due to the limitations of the included studies, multicenter, large-sample, and high-quality RCTS are still needed in the future to further verify this conclusion.

[Effect of dapagliflozin on gene expression of glucose transporter 2 and glucose transporter 4 in kidney of type 2 diabetic rats].

Objective: To investigate the effects of dapagliflozin on the gene expressions of glucose transporter 2 (GLUT2) and glucose transporter 4 (GLUT4) in type 2 diabetic rats. Methods: High fat diet and 40 mg/kg streptozotocin (STZ) were used to establish the rat model of type 2 diabetes mellitus. When the fasting blood glucose (FBG) content was more than or equal to 16.7 mmol/L, the model was established successfully. After successful modeling, the rats were randomly divided into model group (group B, normal saline), dapagliflozin low-dose group (Group C, 0.75 mg/kg), dapagliflozin middle dose group (Group D, 1.5 mg/kg) and dapagliflozin high-dose group (Group E, 3.0 mg/kg), with 6 rats in each group. Six healthy SD rats were selected as normal control group (group A, normal saline). Each group was administrated by gavage once a day for 7 weeks. The body weight, serum FBG, hemoglobin A1c (HbA1c), blood urea nitrogen (BUN) and serum creatinine (Scr) were measured after 7 weeks. The levels of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) in serum and kidney were measured by enzyme-linked immunosorbent assay (ELISA). HE staining was used to observe the pathological changes of kidney. The protein expressions of GLUT2 and GLUT4 were detected by Western blot. RT-qPCR was used to detect the relative expressions of GLUT2 and GLUT4 mRNA in kidney tissue. Results: Compared with group A, the body weight, SOD, GSH-Px levels of rats in each group were significantly decreased (P＜0.05), while the levels of FBG, HbA1c, BUN, SCR and MDA were significantly increased (P＜0.05), renal pathological damage was serious, the relative expressions of GLUT2, GLUT4 mRNA and protein in renal tissue were significantly decreased (P＜0.05). Compared with group B, the body weight, SOD, GSH-Px levels and the mRNA relative expressions of GLUT2 and GLUT4 in group C, group D and group E were significantly increased (P＜0.05), while the levels of FBG, HbA1c, BUN, SCR and MDA were significantly decreased (P＜0.05). The renal pathological damage in group D and group E was significantly alleviated, and the expressions of GLUT2 and GLUT4 protein in renal tissue were significantly increased (all P＜0.05). Conclusion: Dapagliflozin can alleviate the condition of type 2 diabetic rats and up regulate the expression of GLUT2 and GLUT4 genes in kidney.

6-Shogaol ameliorates diabetic nephropathy through anti-inflammatory, hyperlipidemic, anti-oxidative activity in db/db mice.

The prevalence of type 2 diabetes mellitus has been increasing worldwide and more than two thirds of the patients may develop diabetic nephropathy (DN). However, the efficiency of existing approaches on DN progression is limited. 6-Shogaol (6-SG), a major dehydrated derivative of gingerols, possesses various biological properties. The present study was designed to evaluate the possible effects of 6-SG on DN in db/db mice and to investigate the mechanisms. We revealed that 6-SG reduced the levels of fasting blood glucose, serum insulin, C-peptide, glycosylated hemoglobin A1c, and systolic blood pressure. 6-SG decreased the levels of blood urea nitrogen (BUN), serum creatinine, urinary albumin content and albumin/creatinine ratio (ACR), ameliorated the pathological injuries of kidneys, reduced the surface area of Bowman's capsule, Bowman's space, glomerular tuft, and decreased the expression of collagen IV and fibronectin in kidneys of db/db mice. The high levels of systemic and renal triglyceride and cholesterol were decreased by 6-SG. Moreover, 6-SG exhibited anti-inflammatory effects, as reflected by reduction of tumor necrosis factor ɑ (TNFɑ), monocyte chemotactic protein-1 (MCP-1), and IL-6 levels in circulation and kidneys, and decrease of NF-κB expression. Furthermore, 6-SG also inhibited oxidative stress and restored the expression of NF-E2-related factor 2 (Nrf2) in kidneys of db/db mice. In conclusion, we have demonstrated that 6-SG exhibits anti-diabetic and renal protective effects against DN, in which effect the anti-inflammatory, hyperlipidemic, anti-oxidative activities may be involved. Overall, 6-SG could be a promising therapeutic treatment to ameliorate diabetes and the development of DN.

Association of GSTs polymorphisms with risk of gestational diabetes mellitus.

We conducted a case-control study to investigate the association between GSTM1, GSTT1 and GSTP1 IIe105Val polymorphisms and development of gestational diabetes mellitus in a Chinese population. A total of 320 patients with gestational diabetes mellitus and 358 pregnancy subjects were consecutively collected between January 2013 and December 2014. Genotyping for detection of GSTM1, GSTT1 and GSTP1 IIe105Val was conducted by using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphisms) method. By Fisher's exact test, we found that the genotype distributions of GSTP1 IIe105Val were in line with the Hardy-Weinberg equilibrium in control subjects (P=0.57). By Chi-square test, we found significant differences in the genotype distributions of GSTM1 (χ(2)=11.49, P=0.001) and GSTT1 (χ(2)=18.50, P<0.001). Using unconditional logistic analysis, individuals carrying the null genotypes of GSTM1 and GSTT1 were associated with an increased risk of gestational diabetes mellitus when compared with the present genotype, and the adjusted Ors (95% CI) were 1.71 (1.24-2.36) and 2.00 (1.44-2.79), respectively. However, the GSTP1 IIe105Val polymorphism was not associated with an elevated risk of gestational diabetes mellitus. In conclusion, we suggest that the GSTM1 null genotype and GSTT1 null genotype are correlated with an increased risk of gestational diabetes mellitus in a Chinese population.

Silibinin ameliorates steatosis and insulin resistance during non-alcoholic fatty liver disease development partly through targeting IRS-1/PI3K/Akt pathway.

Silibinin (SIL) is a well-studied hepato-protective agent against a spectrum of liver diseases. However, the role of SIL in non-alcoholic fatty liver disease (NAFLD) induced insulin resistance and underlying signaling is not fully characterized. In this study, Sprague-Dawley (SD) rats were fed with high-fat diet to develop NAFLD with or without an SIL co-treatment. NAFLD rats showed typical NAFLD symptoms including histological changes, insulin resistance, and glucose metabolism dysfunction. SIL co-treatment significantly ameliorated these pathological features partly through restoring the IRS-1/PI3K/Akt pathway. In addition, BRL-3A and HepG2 cells were incubated with palmitic acid (PA) to induce steatosis. SIL co-treatment in cells also reduced lipid accumulation, recovered cell viability, and down-regulated the protein expression of resistin, the marker for insulin resistance. Specific blocker of PI3K abolished the ameliorative effects of SIL on cellular steatosis. In conclusion, SIL alleviated steatosis and insulin resistance both in vivo and in vitro partly through regulating the IRS-1/PI3K/Akt pathway.

Administration of ghrelin improves inflammation, oxidative stress, and apoptosis during and after non-alcoholic fatty liver disease development.

We aim to investigate the preventive and therapeutic effects of ghrelin on a rat NAFLD model and possible underlying mechanism. Sprague-Dawley rats were fed with high-fat diet for 8 weeks to induce NAFLD. A group of rats were also treated with ghrelin throughout the NAFLD induction. After 8 weeks, rats were sacrificed for liver injury measurements. Rats with NAFLD showed obvious histological changes including necrosis and inflammation foci, elevated serum enzyme (ALT and AST) levels, dysregulated hepatic lipid metabolism, increased formation of oxidative stress, and lipid peroxidation markers, up-regulated levels of pro-inflammatory cytokines and apoptotic cells in the liver. Treatment of ghrelin improved liver injury through counter-acting those events. The improvement of ghrelin was accompanied with a restoration of LKB1/AMPK and PI3 K/Akt pathways. Ghrelin treatment alone did not influence the healthy rat liver. In addition, "therapeutic" ghrelin administration (2 weeks) after the establishment of early NAFLD symptoms (4 weeks) in rats further proved the beneficial effects of ghrelin. In conclusion, administration of ghrelin could attenuate NAFLD-induced liver injury, oxidative stress, inflammation, and apoptosis partly through the action of LKB1/AMPK and PI3 K/Akt pathways.

Inhibition of GHRH aggravated acetaminophen-induced acute mice liver injury through GH/IGF-I axis.

The aim of the current study is to investigate the effects of growth hormone releasing hormone (GHRH) antagonist on acetaminophen (APAP)-induced acute liver injury in mice. Healthy C57/B6L mice were orally treated with 200 mg/kg APAP with or without a 30-min pre-treatment with 300 µg/kg GHRH antagonist MZ-5-156. After 12 hours, serum, plasma, and liver samples from each mouse were collected for analyses. Our results showed that twelve-hour treatment with APAP caused obvious liver injury, elevated serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, increased oxidative stress, reduced expressions of antioxidant enzymes, accumulated expression of pro-inflammatory cytokines, and increased circulating levels of growth hormone (GH) and insulin-like growth factor-I (IGF-I). Pre-treatment with MZ-5-156 aggravated liver injury, further increased serum ALT and AST levels, exacerbated oxidative stress and inflammation induced by APAP. Treatment of MZ-5-156 also blocked the phosphorylation form and total form of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 5 (STAT5). Treatment of GHRH super-agonist JI-38 immediately after MZ-5-156 treatment partly reversed the liver injury caused by APAP and MZ-5-156. In conclusion, GHRH plays essential protective role in APAP-induced acute liver injury in vivo. The protective properties of GHRH are partially through GH/IGF-I axis and JAK/STAT pathway.