Publications by authors named "Dalma Seboek"

Chronic exposure to glucocorticoid hormones, resulting from either drug treatment or Cushing's syndrome, results in insulin resistance, central obesity, and symptoms similar to the metabolic syndrome. We hypothesized that the major metabolic effects of corticosteroids are mediated by changes in the key metabolic enzyme adenosine monophosphate-activated protein kinase (AMPK) activity. Activation of AMPK is known to stimulate appetite in the hypothalamus and stimulate catabolic processes in the periphery.

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Adipose tissue-derived cytokines are presumably involved in obesity-associated pathologies including type 2 diabetes and atherosclerosis. Here we studied the lipopolysaccharide (LPS)-induced expression dynamics of tumor necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6), IL-8 and IL-10 in human adipose tissue biopsies, in preadipocyte-derived adipocytes, and in mesenchymal stem cell (MSC)-derived adipocytes. TNFalpha, IL-6, IL-8 and IL-10 secretions by adipose tissue explants were increased 5.

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Introduction: Isolation of high-quality RNA from fresh-frozen thyroid tissues stored for more than a decade would open novel options for gene expression profiling. Herein, we describe successful extraction of high-integrity RNA from human thyroid tissues that were stored for more than a decade.

Methods: Seventy-nine samples (15 goitres, 20 follicular adenomas, 30 papillary carcinomas, 14 follicular carcinomas) that were shock-frozen in isopentane and stored for a median of 11 years (range 1-16 years) were processed using standard precipitation and column filtration techniques.

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Mesenchymal cells in the developing pancreas express the neural stem cell marker nestin and the transcription factor islet-1 (Isl-1). Using defined culture conditions we isolated on a single cell basis nestin producing cells from human pancreatic islets. These cells were immortalized with lentiviral vectors coding for telomerase and mBmi.

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Mesenchymal stem cells (MSC) from mouse bone marrow were shown to adopt a pancreatic endocrine phenotype in vitro and to reverse diabetes in an animal model. MSC from human bone marrow and adipose tissue represent very similar cell populations with comparable phenotypes. Adipose tissue is abundant and easily accessible and could thus also harbor cells with the potential to differentiate in insulin producing cells.

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Article Synopsis
  • Nitric oxide (NO) is linked to inflammation and insulin resistance, but its mechanisms in human fat cells are not fully understood.
  • The study found high levels of eNOS mRNA in certain types of human fat tissue, but little to no iNOS mRNA in non-infected subjects, indicating different expressions in response to inflammation.
  • Despite inducing iNOS mRNA in activated adipocytes, iNOS protein and its effects on insulin-related processes remain undetectable, suggesting NO does not play a role in regulating metabolism in these cells.
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Human adipose tissue is a contributor to inflammation- and sepsis-induced elevation of serum procalcitonin (ProCT). Several calcitonin (CT) peptides, including ProCT, CT gene-related peptide (CGRP), and adrenomedullin (ADM) are suspected mediators in human inflammatory diseases. Therefore, we aimed to explore the expression, interactions, and potential roles of adipocyte-derived CT peptide production.

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Somatostatin (SRIF) is a well-known neuroendocrine secretion product. SRIF expression and secretion are induced after inflammation in murine macrophages and in endotoxin-injected sheep and pigs. Because adipocytes have been demonstrated to produce numerous cytokines and peptide hormones, we investigated the expression of SRIF and its receptors (SSTR1-5) in human adipose tissue after inflammatory stimulation in vitro and in tissues from patients with septic disease.

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Objective: To explore the roles of peripheral blood mononuclear cells (PBMCs) and PBMC-derived macrophages in sepsis-related increased procalcitonin and calcitonin gene-related peptide (CGRP) I production.

Design: Prospective, in vitro primary human cell culture study and human tissue samples gene expression analysis.

Setting: University hospital research laboratories.

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Circulating levels of calcitonin precursors (CTpr), including procalcitonin (ProCT), increase up to several thousand-fold in human sepsis, and immunoneutralization improves survival in two animal models of this disease. Herein, we analyzed inflammation-mediated calcitonin I gene (CALC I) expression in human adipocyte primary cultures and in adipose tissue samples from infected and noninfected patients with different levels of serum ProCT. In ex vivo differentiated adipocytes, the expression of CT mRNA increased 24-fold (P < 0.

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