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Liu S.,Tulane University | Zhao Y.,Tulane University | Hempe J.M.,Research Institute for Children | Fonseca V.,Tulane University | Shi L.,Tulane University
Expert Review of Pharmacoeconomics and Outcomes Research | Year: 2012

Hypoglycemia is an acute complication of diabetes that increases morbidity, mortality and economic costs of diabetes. It presents major clinical problems for the management of Type 2 diabetes as this disease represents the great majority of all diabetes cases. Hypoglycemia makes it difficult for some individuals to achieve good glycemic control, reduces quality of life and increases the burden of diabetes to healthcare systems. Understanding hypoglycemia risk factors can help patients with Type 2 diabetes to correct and avoid hypoglycemia. Recently, an increased risk of hypoglycemia with intensive glycemic control has been identified as an important problem in optimally controlling blood glucose levels in patients with Type 2 diabetes. © 2012 Expert Reviews Ltd.

Hempe J.M.,Research Institute for Children | Hempe J.M.,Louisiana State University Health Sciences Center | Ory-Ascani J.,Research Institute for Children
Electrophoresis | Year: 2014

This report describes modifications to a CZE method developed by Serru et al. (Clinical Chemistry 2001, 47, 1321-1324) for the simultaneous analysis of reduced glutathione (GSH) and glutathione disulfide (GSSG). Lowering the pH of the run buffer (75 mmol/L boric acid, 25 mmol/L bis-Tris) from pH 8.4 to 7.8 markedly improved GSH peak area reproducibility and allowed multiple samples to be analyzed without changing run buffers due to ion depletion. Sample preparation using red blood cells (RBC) instead of whole blood, combined with glutathione extraction at a lower concentration of metaphosphoric acid (5%), increased assay sensitivity and decreased interference. CZE assay results for clinical samples containing 1000 to 3200 μmol GSH/L RBC and 100 to 400 μmol GSSG/L RBC were highly correlated (r2 ≥ 0.95) with results obtained using a commercial dithionitrobenze-based glutathione assay. The modified CZE assay has proven useful for the analysis of glutathione in both mouse and human RBC. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Han J.,Research Institute for Children | Liu Y.Q.,Research Institute for Children | Liu Y.Q.,Louisiana State University Health Sciences Center
Journal of Endocrinology | Year: 2010

Pyruvate carboxylase (PC) activity is enhanced in the islets of obese rats, but it is reduced in the islets of type 2 diabetic rats, suggesting the importance of PC in β-cell adaptation to insulin resistance as well as the possibility that PC reduction might lead to hyperglycemia. However, the causality is currently unknown. We used obese Agouti mice (AyL) as a model to show enhanced β-cell adaptation, and type 2 diabetic db/db mice as a model to show severe b-cell failure. After comparison of the two models, a less severe type 2 diabetic Agouti-K (AyK) mouse model was used to show the changes in islet PC activity during the development of type 2 diabetes mellitus (T2DM). AyK mice were separated into two groups: mildly (AyK-M, blood glucose <250 mg/dl) and severely (AyK-S, blood glucose >250 mg/dl) hyperglycemic. Islet PC activity, but not protein level, was increased 1·7-fold in AyK-M mice; in AyK-S mice, islet PC activity and protein level were reduced. All other changes including insulin secretion and islet morphology in AyK-M mice were similar to those observed in AyL mice, but they were worse in AyK-S mice where these parameters closely matched those in db/db mice. In 2-day treated islets, PC activity was inhibited by high glucose but not by palmitate. Our findings suggest that islet PC might play a role in the development of T2DM where reduction of PC activity might be a consequence of mild hyperglycemia and a cause for severe hyperglycemia. © 2010 Society for Endocrinology.

Tran L.,Louisiana State University Health Sciences Center | Ferris M.,Louisiana State University Health Sciences Center | Ferris M.,Research Institute for Children | Norori J.,Research Institute for Children | And 5 more authors.
Pediatrics | Year: 2013

Necrotizing enterocolitis is the most common gastrointestinal emergency in neonates. The etiology is considered multifactorial. Risk factors include prematurity, enteral feeding, hypoxia, and bacterial colonization. The etiologic role of viruses is unclear. We present a case of necrotizing enterocolitis associated with cytomegalovirus and Proteobacteria in a 48-day-old, ex-premature infant and discuss the effects of potential viral-bacterial interactions on host susceptibility to this disease. Pediatrics 2013;131:e318-e322. Copyright © 2013 by the American Academy of Pediatrics.

Chen C.,National Taiwan University | Chen C.,Research Institute for Children | Chang Y.-C.,Mackay Memorial Hospital | Lan M.S.,Research Institute for Children | And 3 more authors.
International Journal of Oncology | Year: 2013

Obesity is known to be an important risk factor for many types of cancer, such as breast, prostate, liver and endometrial cancer. Recently, epidemiological studies have indicated that obesity correlates with an increased risk of developing ovarian cancer, the most lethal gynecological cancer in developed countries. Leptin is predominantly produced by adipocytes and acts as a growth factor and serum leptin levels positively correlate with the amount of body fat. In this study, we investigated the effects of leptin on the growth of ovarian cancer cells and the underlying mechanism(s) of action. Our results showed that leptin stimulated the growth of the OVCAR-3 ovarian cancer cell line using MTT assay and trypan blue exclusion. Using western blot analysis, we found that leptin enhanced the expression of cyclin D1 and Mcl-1, which are important regulators of cell proliferation and the inhibition of apoptosis. To investigate the signaling pathways that mediate the effects of leptin, cells were treated with leptin plus specific inhibitors of JAK2, PI3K/Akt and MEK/ERK1/2 and analysis of the phosphorylation state of proteins was carried out by western blot assays. We showed that the activation of the MEK/ERK1/2 and PI3K/Akt signaling pathways were involved in the growth-stimulating effect of leptin on ovarian cancer cell growth and the specific inhibitors of PI3K/Akt and MEK/ERK1/2 revealed that these two pathways interacted with each other. Our data demonstrate that leptin upregulates the expression of cyclin D1 and Mcl-1 to stimulate cell growth by activating the PI3K/Akt and MEK/ERK1/2 pathways in ovarian cancer.

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