scholarly journals Iron uptake by human reticulocytes at physiologic and sub-physiologic concentrations of iron transferrin: the effect of interaction with aluminum transferrin [see comments]

Blood ◽  
1991 ◽  
Vol 77 (11) ◽  
pp. 2347-2353
Author(s):  
M Cochran ◽  
V Chawtur ◽  
ME Jones ◽  
EA Marshall
Keyword(s):  
Iron Uptake ◽  
Surface Phenomena ◽  
Conventional View ◽  
Parallel Processes ◽  
Placental Blood ◽  
Diferric Transferrin ◽  
Transferrin Uptake ◽  
Kinetics Of ◽  
Insight Into

We have studied the interaction, in vitro, between diferric transferrin (FeTr), aluminum transferrin (AlTr), and human reticulocytes harvested from human placental blood. In particular, we aimed to determine the extent to which the kinetics of AlTr and FeTr differed. Using transferrin labeled with either 59Fe or 125I, the association of radiotracer with reticulocytes, as a function both of time and of transferrin concentration, was examined. Under the conditions of the experiments, the data are consistent with a mechanism involving at least three processes. Two early processes acting in parallel behave as a high-affinity saturable receptor and a low-affinity non-saturable receptor, neither of which distinguish between AlTr and FeTr. In a subsequent process, AlTr and FeTr exhibit different kinetics. This third process may be saturated by FeTr but not by AlTr. Interpreted in terms of a current conventional view of metallo-transferrin uptake, we conjecture that the early parallel processes involve cell surface phenomena including classical transferrin-receptor binding, and that the subsequent process represents events, possibly intracellular, involved in metallo-transferrin dissociation or further iron transport. The extent to which AlTr influences the interaction of FeTr with reticulocytes offers insight into both the normal physiology of iron uptake and the potential for toxicity by aluminum.

scholarly journals Iron uptake by human reticulocytes at physiologic and sub-physiologic concentrations of iron transferrin: the effect of interaction with aluminum transferrin [see comments]

Blood ◽  
1991 ◽  
Vol 77 (11) ◽  
pp. 2347-2353 ◽  
Author(s):  
M Cochran ◽  
V Chawtur ◽  
ME Jones ◽  
EA Marshall
Keyword(s):  
Iron Uptake ◽  
Surface Phenomena ◽  
Conventional View ◽  
Parallel Processes ◽  
Placental Blood ◽  
Diferric Transferrin ◽  
Transferrin Uptake ◽  
Kinetics Of ◽  
Insight Into

Abstract We have studied the interaction, in vitro, between diferric transferrin (FeTr), aluminum transferrin (AlTr), and human reticulocytes harvested from human placental blood. In particular, we aimed to determine the extent to which the kinetics of AlTr and FeTr differed. Using transferrin labeled with either 59Fe or 125I, the association of radiotracer with reticulocytes, as a function both of time and of transferrin concentration, was examined. Under the conditions of the experiments, the data are consistent with a mechanism involving at least three processes. Two early processes acting in parallel behave as a high-affinity saturable receptor and a low-affinity non-saturable receptor, neither of which distinguish between AlTr and FeTr. In a subsequent process, AlTr and FeTr exhibit different kinetics. This third process may be saturated by FeTr but not by AlTr. Interpreted in terms of a current conventional view of metallo-transferrin uptake, we conjecture that the early parallel processes involve cell surface phenomena including classical transferrin-receptor binding, and that the subsequent process represents events, possibly intracellular, involved in metallo-transferrin dissociation or further iron transport. The extent to which AlTr influences the interaction of FeTr with reticulocytes offers insight into both the normal physiology of iron uptake and the potential for toxicity by aluminum.

scholarly journals Iron distribution in Belgrade rat reticulocytes after inhibition of heme synthesis with succinylacetone

Blood ◽  
1993 ◽  
Vol 81 (12) ◽  
pp. 3414-3421 ◽  
Author(s):  
LM Garrick ◽  
K Gniecko ◽  
Y Liu ◽  
DS Cohan ◽  
JA Grasso ◽  
...  
Keyword(s):  
Iron Uptake ◽  
Iron Transport ◽  
Aminolevulinic Acid ◽  
Specific Inhibitor ◽  
Hypochromic Anemia ◽  
Endocytic Vesicle ◽  
Heme Synthesis ◽  
Diferric Transferrin ◽  
Rat Reticulocytes ◽  
Insight Into

Abstract We have used succinylacetone (4,6-dioxoheptanoic acid), a specific inhibitor of delta-aminolevulinic acid dehydrase, to gain insight into the defect in iron metabolism in the Belgrade anemia. The Belgrade rat has an inherited microcytic, hypochromic anemia associated with poor iron uptake into developing erythroid cells. Succinylacetone inhibits heme synthesis, leading to nonheme iron accumulation in mitochondria and cytosol of normal reticulocytes. When succinylacetone is used to inhibit Belgrade heme synthesis, iron from diferric transferrin does not accumulate in the stromal fraction that contains mitochondria, nor does 59Fe accumulate in the nonheme cytosolic fraction. Hence, the defect in the Belgrade rat reticulocyte occurs in the endocytic vesicle or in a step subsequent to iron transit from the vesicle but before the nonheme cytosolic or mitochondrial iron fractions. Therefore, the mutation affects either the release of iron from transferrin or iron transport from the vesicle to the mitochondrion.

scholarly journals Iron distribution in Belgrade rat reticulocytes after inhibition of heme synthesis with succinylacetone

Blood ◽  
1993 ◽  
Vol 81 (12) ◽  
pp. 3414-3421 ◽  
Author(s):  
LM Garrick ◽  
K Gniecko ◽  
Y Liu ◽  
DS Cohan ◽  
JA Grasso ◽  
...  
Keyword(s):  
Iron Uptake ◽  
Iron Transport ◽  
Aminolevulinic Acid ◽  
Specific Inhibitor ◽  
Hypochromic Anemia ◽  
Endocytic Vesicle ◽  
Heme Synthesis ◽  
Diferric Transferrin ◽  
Rat Reticulocytes ◽  
Insight Into

We have used succinylacetone (4,6-dioxoheptanoic acid), a specific inhibitor of delta-aminolevulinic acid dehydrase, to gain insight into the defect in iron metabolism in the Belgrade anemia. The Belgrade rat has an inherited microcytic, hypochromic anemia associated with poor iron uptake into developing erythroid cells. Succinylacetone inhibits heme synthesis, leading to nonheme iron accumulation in mitochondria and cytosol of normal reticulocytes. When succinylacetone is used to inhibit Belgrade heme synthesis, iron from diferric transferrin does not accumulate in the stromal fraction that contains mitochondria, nor does 59Fe accumulate in the nonheme cytosolic fraction. Hence, the defect in the Belgrade rat reticulocyte occurs in the endocytic vesicle or in a step subsequent to iron transit from the vesicle but before the nonheme cytosolic or mitochondrial iron fractions. Therefore, the mutation affects either the release of iron from transferrin or iron transport from the vesicle to the mitochondrion.

Nanomechanical Microcantilevers for In-Vitro Biomolecular Detection

2007 ◽  
Author(s):  
Kilho Eom ◽  
Tae Yun Kwon ◽  
Jinsung Park ◽  
Sungsoo Na ◽  
Dae Sung Yoon ◽  
...  
Keyword(s):  
Real Time ◽  
Biological Molecules ◽  
Label Free ◽  
Biomolecular Detection ◽  
Label Free Detection ◽  
Detection Of Biomolecules ◽  
Kinetics Of ◽  
Insight Into

Nanomechanical microcantilevers have enabled the sensitive label-free detection of chemical and/or biological molecules. In recent years, resonating microcantilevers have achieved the unprecedented sensitivity in detecting molecules. In this article, we review our current works on the label-free detection of biomolecules based on resonating microcantilevers. Our piezoelectric thick film microcantilevers exhibit the relatively high quality factor in a viscous liquid, indicating the potential of our cantilever to in situ biosensor applications for real-time detection of biomolecular interactions. It is shown that our microcantilevers allow the noise-free real-time monitoring of biomolecular recognitions, providing the insight into kinetics of biomolecular recognitions.

scholarly journals Preferential utilization in vitro of iron bound to diferric transferrin by rabbit reticulocytes

1977 ◽  
Vol 166 (2) ◽  
pp. 175-179 ◽  
Author(s):  
E J Zapolski ◽  
J V Princiotto
Keyword(s):  
Iron Uptake ◽  
Total Iron ◽  
The Other ◽  
Ferric Ion ◽  
Comparative Experiment ◽  
Partially Saturated ◽  
Diferric Transferrin ◽  
Later Phase ◽  
Rabbit Reticulocytes

59Fe uptake by rabbit reticulocytes from human transferrin-bound iron was studied by using transferrin solutions (35, 50, 65, 80 and 100% saturated with iron) whose only common characteristic was their content of diferric transferrin. During the early incubation period, 59Fe uptake from each preparation by reticulocytes was identical despite wide variations in amounts of total transferrin, total iron, monoferric transferrin and apotransferrin in solution. During the later phase of incubation, rate of uptake declined and was proportional to each solution's monoferric transferrin content. Uptake was also studied in a comparative experiment which used two identical, partially saturated transferrin preparations, one uniformly 59Fe-labelled and the other tracer-labelled with [59Fe]diferric transferrin. In both experiments, iron uptake by reticulocytes corresponded to utilization of a ferric ion from diferric transferrin before utilization of iron from monoferric transferrin.

Transferrin and iron uptake by rat hepatocytes in culture

1984 ◽  
Vol 246 (1) ◽  
pp. G26-G33 ◽  
Author(s):  
M. A. Page ◽  
E. Baker ◽  
E. H. Morgan
Keyword(s):  
Iron Uptake ◽  
Rat Hepatocytes ◽  
Molar Ratio ◽  
Adult Rat ◽  
Iron Saturation ◽  
Primary Monolayer Culture ◽  
Primary Monolayer ◽  
Diferric Transferrin ◽  
Transferrin Uptake ◽  
Linear Manner

Hepatic iron and transferrin metabolism was studied using rat transferrin doubly labeled with 59Fe and 125I and adult rat hepatocytes in primary monolayer culture. Iron uptake was linear for 48 h while transferrin uptake was biphasic. Total transferrin and iron uptake increased in a linear manner as the transferrin concentration was raised up to at least 130 microM. This indicates that transferrin and iron are taken up primarily by nonspecific processes, possibly by endocytosis (absorptive or fluid) and by the action of iron chelators. However, some evidence indicated the presence of receptors for diferric transferrin on hepatocytes: the molar ratio of iron to transferrin accumulation increased with incubation time, transferrin and iron uptake was proportional to the iron saturation of the transferrin, apotransferrin displaced bound apotransferrin but had no effect on the binding of diferric transferrin, and the molar ratio of iron to transferrin uptake decreased with increasing transferrin concentrations.

Utilization of Optical Polarization Microscopy in the Study of Sorption Characteristics of Wound Dressing Host Materials

2014 ◽  
Vol 20 (2) ◽  
pp. 561-565 ◽  
Author(s):  
Miha Devetak ◽  
Zdenka Peršin ◽  
Karin Stana-Kleinschek ◽  
Uroš Maver
Keyword(s):  
Wound Dressing ◽  
Sorption Kinetics ◽  
Wound Dressings ◽  
Polarization Microscopy ◽  
Host Materials ◽  
Kinetics Of ◽  
Dressing Materials ◽  
Insight Into ◽  
Sorption Characteristics

AbstractPolarization microscopy was used for evaluation of kinetics of diclofenac sorption in three different wound dressing materials. The sorption kinetics can be evaluated by radii change and intensity of the light traveling through the fiber. The most frequently used host materials for drugs in wound dressings are alginate, polyesters such as polyethylene terephthalate, and viscose. We studied sorption of diclofenac as an example drug. Effective, but rather simple in vitro simulation of diclofenac sorption gives insight into the applicability of the mentioned materials for development of wound healing materials.

Uptake and distribution of transferrin and iron in perfused, iron-deficient rat liver

1989 ◽  
Vol 256 (6) ◽  
pp. G1022-G1027
Author(s):  
J. M. Holmes ◽  
E. H. Morgan
Keyword(s):  
Iron Deficiency ◽  
Rat Liver ◽  
Iron Uptake ◽  
Subcellular Fractionation ◽  
Rat Serum ◽  
Iron Deficient ◽  
Uptake Process ◽  
Transferrin Uptake ◽  
Rat Serum Albumin

Uptake of transferrin and iron by the rat liver was investigated by perfusion in vitro with 125I-59Fe-labeled rat transferrin and subcellular fractionation on sucrose density gradients. Most of the 125I-transferrin was located in a low-density vesicle fraction. The 59Fe was in three peaks, of lower, the same, and higher densities than the transferrin peak. Iron deficiency resulted in a large increase in transferrin and iron uptake into all subcellular fractions. When livers were perfused with increasing concentrations of transferrin the uptake into the different peaks of transferrin and iron increased in a curvilinear fashion, which indicated that uptake occurred by saturable and nonsaturable processes, both of which increased in iron deficiency. In contrast, the uptake of 131I-labeled rat serum albumin increased linearly with concentration, and there was no difference between control and iron-deficient livers. It is concluded that iron deficiency leads to an increase in the number of high-affinity transferrin receptors and receptor-mediated endocytosis of transferrin. It also increases a nonsaturable transferrin uptake process that is probably due to adsorptive, but selective, endocytosis of transferrin.

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

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