Comparison study of iron preparations using a human intestinal model

Iron deficiency and related iron deficiency anaemia (IDA) are the most prevalent nutritional disorders worldwide. The standard treatment involves supple-mentation with solid or liquid iron supplement preparations, usually based on a ferrous salt such as ferrous sulphate, ferrous fumarate, or ferrous gluconate. In the present study, we compared iron uptake and absorption from various solid and liquid iron supplement preparations currently available in the United Kingdom using the well-characterised human epithelial adenocarcinoma cell line Caco-2. Intracellular ferritin protein formation by the Caco-2 cell was considered an indicator of cellular iron uptake and absorption. We investigated the effects of formulation ingredients at a defined pH on iron uptake and absorption, and designed a novel two-stage dissolution-absorption protocol that mimicked physiological conditions. Our experiments revealed wide variations in the rate of dissolution between the various solid iron preparations. Conventional-release ferrous iron tablets dissolved rapidly (48 ± 4 mins to 64 ± 4 mins), whereas modified-released tablets and capsules took significantly longer to undergo complete dissolution (274 ± 8 to 256 ± 8 mins). Among the solid iron preparations, ferrous sulphate conventional-release tablets demon-strated the highest iron absorption, whereas modified-release ferrous prepa-rations demonstrated uniformly low iron absorption, as compared to the control (P < 0.05). Taken together, our results demonstrate that there are wide-ranging variations in dissolution times and iron uptake from oral iron preparations, with the physical characteristics of the preparation as well as the form of iron playing a key role

PPARs and the orchestration of metabolic fuel selection

This contribution describes recent advances in our knowledge of the regulatory interactions between the two major oxidative fuels glucose and lipid. It also addresses how the metabolic abnormalities associated with insulin resistance and ischemic diseases impair the ability of skeletal muscle to switch between the use of alternative metabolic fuels and the ability of adipose tissue to function appropriately in relation to the body's requirements for triglyceride mobilisation or storage, as appropriate to nutritional status. We discuss how targeting PPARs might ameliorate metabolic inflexibility in muscle through altered expression of pyruvate dehydrogenase kinase (PDK) isoforms and impact the functions of the adipocyte in lipid buffering and energy homeostasis. Focus has been placed on the participation of the regulatory pyruvate dehydrogenase kinases, PPAR targets, both in the beneficial and the potentially adverse actions of the PPARs in metabolic control

Positioning and stretching of actin filaments by electric fields

Wigge C, Hinssen H, Reiss G, Herth S. Positioning and stretching of actin filaments by electric fields. APPLIED PHYSICS LETTERS. 2010;96(24): 243703.The alignment of biological filaments on surfaces offers a high potential for controllable geometries in lab-on-a-chip-structures and micrototal analysis systems. Actin is a polar filamentous protein with a diameter of 7-8 nm that can be manipulated with strong electric fields. It is demonstrated that with the use of microelectrodes or nanoelectrodes and electric fields of 20 kV/m single actin filaments can be manipulated, stretched, and positioned between gold electrodes. (C) 2010 American Institute of Physics. [doi:10.1063/1.3455338