Search results for "homeostasi"
showing 10 items of 636 documents
Oxidant stress: the role of nutrients in cell-lipoprotein interactions
1999
Oxidant stress is increasingly becoming an important hypothesis to explain the genesis of several pathologies, including cancer, atherosclerosis and also ageing. Beside a few rare genetic defects, dietary factors are thought to play a key role in the regulation of the production of reactive oxygenated species. An imbalance between nutrients, and in particular those involved in antioxidant status, could explain the onset of an enhanced production of free radicals. We will briefly review information concerning oxidation of lipids and lipoproteins which lead to atherothrombosis. We also present new findings supporting a role for blood platelets in generating oxidant species. New data are also …
Hematopoietic Stem Cells Reversibly Switch from Dormancy to Self-Renewal during Homeostasis and Repair
2008
Bone marrow hematopoietic stem cells (HSCs) are crucial to maintain lifelong production of all blood cells. Although HSCs divide infrequently, it is thought that the entire HSC pool turns over every few weeks, suggesting that HSCs regularly enter and exit cell cycle. Here, we combine flow cytometry with label-retaining assays (BrdU and histone H2B-GFP) to identify a population of dormant mouse HSCs (d-HSCs) within the lin(-)Sca1(+)cKit(+)CD150(+)CD48(-)CD34(-) population. Computational modeling suggests that d-HSCs divide about every 145 days, or five times per lifetime. d-HSCs harbor the vast majority of multilineage long-term self-renewal activity. While they form a silent reservoir of th…
TyG index, HOMA score and viral load in patients with chronic hepatitis C due to genotype 1.
2011
Summary. The triglycerides × glucose (TyG) index is a recently proposed surrogate marker of insulin resistance (IR), calculated from fasting plasma triglyceride and glucose concentrations. We tested the host and viral factors associated with Tyg and homeostasis model assessment (HOMA) scores, comparing their associations with histological features and with sustained virological response (SVR) in patients with genotype 1 chronic hepatitis C(G1CHC). Three hundred and forty consecutive patients with G1CHC were considered. All had a liver biopsy scored by one pathologist for staging and grading (Scheuer), and graded for steatosis, which was considered moderate–severe if ≥30%. Anthropometric an…
Calcium Metabolism in the Elderly
1998
Mineral homeostasis represents one of the multiple areas at risk in the elder population. This includes the ion calcium, which is the most abundant inorganic element in the human body and an essential key for many physiologic processes (1).
The Role of Vitamin K in Bone Remodeling and Osteoporosis
2012
Vitamin K is an essential fat soluble vitamin involved in the regulation of normal coagulation. However, growing evidence highlights that this molecule appears to be also implicated in the regulation of other important biological functions such as bone mineralization, calcium homeostasis, apoptosis, cell growth and signal transduction. In particular, many studies have focused their attention on the protective effects of vitamin K on bone tissue in the outlook of its use in the prevention and treatment of osteoporosis in post-menopausal women. The objective of the present paper is to review data of the literature regarding the metabolic effects of Vitamin K in bone tissue and its clinical ro…
Calcium Absorption in Health and Disease
1972
Calcium (Ca) metabolism and intestinal Ca absorption have attracted special attention ever since the discovery of vitamin D and the definition of the clinical entities of disturbances of Ca homeostasis in the first three decades of this century. Since then, many details of Ca transport and vitamin D metabolism have accumulated, but only in very recent years have new ideas and findings brought about rapid progress in this field. There is now a startling activity in the investigation of the physiology and pathogenesis of vitamin D and Ca metabolism.
Maintenance of the intestinal tube in Caenorhabditis elegans: the role of the intermediate filament protein IFC-2.
2008
The Caenorhabditis elegans intestinal lumen is surrounded by a dense cytoplasmic network that is laterally attached to the junctional complex and is referred to as the endotube. It localizes to the terminal web region which anchors the microvillar actin filament bundles and is particularly rich in intermediate filaments. To examine their role in intestinal morphogenesis and function, C. elegans reporter strains were generated expressing intestine-specific CFP-tagged intermediate filament polypeptide IFB-2. When these animals were treated with dsRNA against intestinal intermediate filament polypeptide IFC-2, the endotube developed multiple bubble-shaped invaginations that protruded into the …
Mast Cells Infiltrating Inflamed or Transformed Gut Alternatively Sustain Mucosal Healing or Tumor Growth.
2015
Abstract Mast cells (MC) are immune cells located next to the intestinal epithelium with regulatory function in maintaining the homeostasis of the mucosal barrier. We have investigated MC activities in colon inflammation and cancer in mice either wild-type (WT) or MC-deficient (KitW-sh) reconstituted or not with bone marrow-derived MCs. Colitis was chemically induced with dextran sodium sulfate (DSS). Tumors were induced by administering azoxymethane (AOM) intraperitoneally before DSS. Following DSS withdrawal, KitW-sh mice showed reduced weight gain and impaired tissue repair compared with their WT littermates or KitW-sh mice reconstituted with bone marrow-derived MCs. MCs were localized i…
Breast cancer cell lines contain functional cancer stem cells with metastatic capacity and a distinct molecular signature.
2009
Abstract Tumors may be initiated and maintained by a cellular subcomponent that displays stem cell properties. We have used the expression of aldehyde dehydrogenase as assessed by the ALDEFLUOR assay to isolate and characterize cancer stem cell (CSC) populations in 33 cell lines derived from normal and malignant mammary tissue. Twenty-three of the 33 cell lines contained an ALDEFLUOR-positive population that displayed stem cell properties in vitro and in NOD/SCID xenografts. Gene expression profiling identified a 413-gene CSC profile that included genes known to play a role in stem cell function, as well as genes such as CXCR1/IL-8RA not previously known to play such a role. Recombinant int…
Cell volume homeostatically controls the rDNA repeat copy number and rRNA synthesis rate in yeast
2021
[Abstract] The adjustment of transcription and translation rates to the changing needs of cells is of utmost importance for their fitness and survival. We have previously shown that the global transcription rate for RNA polymerase II in budding yeast Saccharomyces cerevisiae is regulated in relation to cell volume. Total mRNA concentration is constant with cell volume since global RNApol II-dependent nascent transcription rate (nTR) also keeps constant but mRNA stability increases with cell size. In this paper, we focus on the case of rRNA and RNA polymerase I. Contrarily to that found for RNA pol II, we detected that RNA polymerase I nTR increases proportionally to genome copies and cell s…