Optimization of isolation and transfection conditions of maize endosperm protoplasts.

BACKGROUND: Endosperm-trait related genes are associated with grain yield or quality in maize. There are vast numbers of these genes whose functions and regulations are still unknown. The biolistic system, which is often used for transient gene expression, is expensive and involves complex protocol. Besides, it cannot be used for simultaneous analysis of multiple genes. Moreover, the biolistic system has little physiological relevance when compared to cell-specific based system. Plant protoplasts are efficient cell-based systems which allow quick and simultaneous transient analysis of multiple genes. Typically, PEG-calcium mediated transfection of protoplast is simple and cost-effective. Notably, starch granules in cereal endosperm may diminish protoplast yield and integrity, if the isolation and transfection conditions are not accurately measured. Prior to this study, no PEG-calcium mediated endosperm protoplast system has been reported for cereal crop, perhaps, because endosperm cells accumulate starch grains. RESULTS: Here, we showed the uniqueness of maize endosperm-protoplast system (EPS) in conducting endosperm cell-based experiments. By using response surface designs, we established optimized conditions for the isolation and PEG-calcium mediated transfection of maize endosperm protoplasts. The optimized conditions of 1% cellulase, 0.75% macerozyme and 0.4 M mannitol enzymolysis solution for 6 h showed that more than 80% protoplasts remained viable after re-suspension in 1 ml MMG. The EPS was used to express GFP protein, analyze the subcellular location of ZmBT1, characterize the interaction of O2 and PBF1 by bimolecular fluorescent complementation (BiFC), and simultaneously analyze the regulation of ZmBt1 expression by ZmMYB14. CONCLUSIONS: The described optimized conditions proved efficient for reasonable yield of viable protoplasts from maize endosperm, and utility of the protoplast in rapid analysis of endosperm-trait related genes. The development of the optimized protoplast isolation and transfection conditions, allow the exploitation of the functional advantages of protoplast system over biolistic system in conducting endosperm-based studies (particularly, in transient analysis of genes and gene regulation networks, associated with the accumulation of endosperm storage products). Such analyses will be invaluable in characterizing endosperm-trait related genes whose functions have not been identified. Thus, the EPS will benefit the research of cereal grain yield and quality improvement.

Postconditioning with Nitrates Protects Against Myocardial Reperfusion Injury: A New Use for an Old Pharmacological Agent.

Early reperfusion remains the key therapy to salvage viable myocardium and must be applied as soon as possible following an acute myocardial infarction (AMI) to attenuate the ischemic insult. However, reperfusion injury may develop following reintroduction of blood and oxygen to vulnerable myocytes, which results in more severe cell death than in the preceding ischemic episode. Ischemic postconditioning (I-PostC) provides a cardioprotective effect in combination with pharmacological agents. Although nitrates have been tested in many experimental and clinical studies of acute AMI to evaluate the cardioprotective effect, few investigations have been focused on nitrates postconditioning in patients undergoing percutaneous coronary intervention (PCI). This review presents the manifestations of myocardial reperfusion injury (RI) and potential mechanisms underlying it, and provides the mechanisms involved in the cardioprotection of I-PostC. We also present a new therapeutic approach to attenuate RI by use of an 'old' agent - nitrates - in AMI patients.

Retracted: Cardioprotective Effect of Isosorbide Dinitrate Postconditioning Against Rat Myocardial Ischemia-Reperfusion Injury In Vivo.

The Fig 4C and 4D are the same, but the author showed them as two parallel groups. Reference: Cardioprotective Effect of Isosorbide Dinitrate Postconditioning Against Rat Myocardial Ischemia-Reperfusion Injury In Vivo Xinwen Zhao, Mengjuan Wang, Mei Li, Na Wu, Dalin Song Med Sci Monit 2019;25: 1629-1636 10.12659/MSM.912814.

Cardioprotective Effect of Isosorbide Dinitrate Postconditioning Against Rat Myocardial Ischemia-Reperfusion Injury In Vivo.

BACKGROUND This study investigated the cardioprotective effect of isosorbide dinitrate (ISDN) postconditioning against rat myocardial ischemia/reperfusion injury in vivo and provided a theoretical basis for clinical application. MATERIAL AND METHODS We randomly divided 32 Wistar rats into 4 groups: sham group, I/R (ischemia/reperfusion) group, I-PostC group (with 3 cycles of 30 s reperfusion and 30 s reocclusion applied at the onset of reperfusion), and P-PostC group (nitrate postconditioning: isosorbide dinitrate (5mg/kg) was given 1 min before reperfusion). The left anterior descending artery (LAD) was occluded for 40 min, followed by a 180-min reperfusion. Relevant indicators were tested. The LAD was occluded again, then we determined the myocardial infarct size. Paraffinized sections were prepared and TUNEL detection was performed. RESULTS There were no significant differences in ischemic sizes between different groups. Compared with the I/R group, the levels of cTnI and myocardial infarct size in the I-PostC group and P-PostC group were significantly decreased (p<0.05). However, there were no significant difference between the I-PostC group and P-PostC group. Compared with the sham-operated group, the levels of cTnI and MDA in the I/R group, I-PostC group, and P-PostC group were significantly increased (p<0.05) and the levels of SOD were significantly decreased (p<0.05). Compared with the I/R group, I-PostC and P-PostC decreased the level of MDA and increased the level of SOD (both P<0.05). CONCLUSIONS ISDN postconditioning induces a similar cardioprotective effect as I-PostC. The potential mechanisms of cardioprotection of ISDN postconditioning might be via improvement of myocardial antioxidant capacity and reduced generation of reactive oxygen species.

Proteomics Analysis of Blood Serums from Alzheimer's Disease Patients Using iTRAQ Labeling Technology.

Alzheimer' disease (AD) is the most common form of dementia affecting up to 6% of the population over the age of 65. In order to discover differentially expressed proteins that might serve as potential biomarkers, the serums from AD patients and healthy controls were compared and analyzed using the proteomics approach of isobaric tagging for relative and absolute quantitation (iTRAQ). For the first time, AD biomarkers in serums are investigated in the Han Chinese population using iTRAQ labeled proteomics strategy. Twenty-two differentially expressed proteins were identified and out of which nine proteins were further validated with more sample test. Another three proteins that have been reported in the literature to be potentially associated with AD were also investigated for alteration in expression level. Functions of those proteins were mainly related to the following processes: amyloid-ß (Aß) metabolism, cholesterol transport, complement and coagulation cascades, immune response, inflammation, hemostasis, hyaluronan metabolism, and oxidative stress. These results support current views on the molecular mechanism of AD. For the first time, differential expression of zinc-alpha-2-glycoprotein (AZGP1), fibulin-1 (FBLN1), platelet basic protein (PPBP), thrombospondin-1 (THBS1), S100 calcium-binding protein A8 (S100A8), and S100 calcium-binding protein A9 (S100A9) were detected in the serums of AD patients compared with healthy controls. These proteins might play a role in AD pathophysiology and serve as potential biomarkers for AD diagnosis. Specifically, our results strengthened the crucial role of Aß metabolism and blood coagulation in AD pathogenesis and proteins related to these two processes may be used as peripheral blood biomarkers for AD.

Link between type 2 diabetes and Alzheimer's disease: from epidemiology to mechanism and treatment.

The aim of this paper is to provide a comprehensive review of the epidemiological evidence linking type 2 diabetes mellitus and its related conditions, including obesity, hyperinsulinemia, and metabolic syndrome, to Alzheimer's disease (AD). Several mechanisms could help to explain this proposed link; however, our focus is on insulin resistance and deficiency. Studies have shown that insulin resistance and deficiency can interact with amyloid-ß protein and tau protein phosphorylation, each leading to the onset and development of AD. Based on those epidemiological data and basic research, it was recently proposed that AD can be considered as "type 3 diabetes". Special attention has been paid to determining whether antidiabetic agents might be effective in treating AD. There has been much research both experimental and clinical on this topic. We mainly discuss the clinical trials on insulin, metformin, thiazolidinediones, glucagon-like peptide-1 receptor agonists, and dipeptidyl peptidase-4 inhibitors in the treatment of AD. Although the results of these trials seem to be contradictory, this approach is also full of promise. It is worth mentioning that the therapeutic effects of these drugs are influenced by the apolipoprotein E (APOE)-ε4 genotype. Patients without the APOE-ε4 allele showed better treatment effects than those with this allele.

Relationship between tissue type plasminogen activator and coronary vulnerable plaque in patients with acute coronary syndrome: virtual histological study.

BACKGROUND: The association between vulnerability of plaque assessed with intravascular ultrasound (IVUS) and plasma levels of fibrinolytic biomarkers was determined in patients with acute coronary syndrome (ACS). However, few data are available on the relationship between the levels of tissue type plasminogen activator (t-PA) and virtual histological intravascular ultrasound (VH-IVUS) signs of plaque instability. METHODS: Eighty-nine patients with ACS were enrolled in the study. Blood was collected to measure t-PA levels by liquid phase bead flow cytometry. Eighty-nine nonbifurcate lesions (identified by coronary angiography and ECG) were investigated using IVUS before catheterization. IVUS radiofrequency data obtained with a 20 MHz catheter were analyzed with IVUS virtual histological software. The areas of plaque and media were calculated and lesions were classified into two groups: VH-IVUS derived thin cap fibroatheroma (VH-TCFA) and non-VH-TCFA plaque. RESULTS: Plasma t-PA level in the patients with TCFA was significantly lower than that with non-TCFA ((1489+/-715) pg/ml vs (2163+/-1004) pg/ml). Decreased plasma levels of t-PA were associated with plaque vulnerability. Plasma levels of t-PA correlated negatively with plaque plus media and necrotic core in plaque in patients with ACS. CONCLUSIONS: t-PA is an independent risk factor and a powerful predictor of vulnerable plaques. Decreased levels of t-PA may reflect instability of atherosclerotic plaques and might therefore serve as noninvasive determinants of those at high risk for consequent adverse events.

Biomarkers, age, and coronary artery remodeling in patients with acute coronary syndrome.

To investigate the relationship between age and coronary artery remodeling in patients with acute coronary syndrome (ACS), 56 patients with ACS were identified by intravascular ultrasound (IVUS). Remodeling index (RI) (37 cases of RI > or =1 vs 19 cases of RI <1) and dimidiate age groups (27 patients younger than 60 years vs 29 patients 60 years or older) were compared, and the relationships among biomarkers, age, and arterial remodeling were analyzed. There was a significant difference in age between positive and negative remodeling groups (55+/-13 vs 62+/-10 years; P=.038); RI and triglyceride level showed a statistical correlation (r=0.32; P=.02) and a significant inverse correlation between age and RI (r=-0.47; P<.001). The multivariable linear regression analysis demonstrated that age was an independent predictor of RI (Bate -0.37; 95% confidence interval, 0.93-1.08; P=.04). Age may be an important factor of arterial remodeling. Low-density lipoprotein or triglyceride level may be associated with attenuated coronary vascular remodeling with aging.

[Relationship between serum vasoactive factors and plaque morphology in patients with acute coronary syndrome].

OBJECTIVE: To investigate the relationship between vasoactive factors and plaque morphology in patients with acute coronary syndrome (ACS). METHODS: Intravascular ultrasound (IVUS) were performed and 7 serum vasoactive factors (sPE, tPA, MCP-1, IL-8, IL-6, sVCAM-1 and sCD40L) were measured through cytometric bead array, serum hs-CRP, HCY, glucose and lipid level were also determined in consecutively enrolled 56 patients with ACS. The changes of bio-factors were compared between vulnerable plaque and non-vulnerable plaque groups, AMI and UA patients, and patients with or without plaque rupture. RESULTS: Biomarkers were similar between patients with unstable angina pectoris and AMI. hs-CRP [(18.9 +/- 4.9) mg/l vs. (5.8 +/- 3.6) mg/L)] and IL-6 [19.5 pg/ml (9.2 - 44.6 pg/ml) vs. 5.3 pg/ml (2.3 - 13.4 pg/ml)] were significantly higher in the group of vulnerable plaque (P < 0.05) compared to non-vulnerable plaques group. sCD40L [(474 +/- 126) pg/ml vs. (238 +/- 35) pg/ml], sPE [(107.2 +/- 39.9) microg/ml vs. (49.1 +/- 5.6) microg/ml] and MCP-1 [(132 +/- 18) pg/ml vs. (127 +/- 13) pg/ml] were significantly increased in the plaque rupture group than that in non-plaque rupture group (all P < 0.05). Increasing of sCD40L, MCP-1, sPE and TC were independent risk factors for plaque rupture. CONCLUSIONS: IL-6 and hs-CRP are biomarkers for vulnerable plaques and diagnosis of acute myocardial infarction. sCD40L, MCP-1 and sPE may serve as the potential markers predicting plaque rupture in patients with ACS.

[Influence of catecholamines on myocardium in experimental septic shock].

OBJECTIVE: To study the influence of catecholamine on myocardium in rats with septic shock and its mechanism by biochemical and pathophysiological methods to evaluate the underlying pathophysiologic mechanism of myocardial damage and the influence of catecholamine on the myocardial injury. METHODS: Septic shock was replicated in rats by cecal ligation and puncture (CLP). Dobutamine (DB), norepinephrine (NE) and combination of DB and NE were used in the lowest dose. The rats were randomly divided into sham operations, CLP control group, CLP+DB group, CLP+NE group and CLP+DB+NE group, 8 rats in each group. Troponin I (cTnI) and total creatine kinase (CK) were measured, and myocardial tissue was examined under light microscopy and electron microscopy. RESULTS: An significantly increased cTnI level was found in CLP septic shock rats, compared with sham rats (P<0.05). In the present study, the use of DB or NE alone, or the combination of the two drugs, was not found to influence the cTnI levels. But, the total CK levels in catecholamine-treated group were significantly increased (P<0.05). There was no statistically significant correlation between cTnI and CK levels. Morphological study confirmed the results of cTnI. Findings that were common in the myocardium of CLP septic shock rats included extracellular and intracellular edema as well as mitrochondrial injury. However, no conclusive evidence was found for the influence of catecholamine on myocardial damage. CONCLUSION: No evidence of the influence of catecholamine on myocardial damage is found. Pathological study suggests that myocardial injury is the result of ischemia.