The retinal pigment epithelium (RPE) is a monolayer of cuboidal cells that lies in close association with the rod and cone photoreceptors. This epithelium has diverse features, three of which are discussed in some detail in this review, namely the daily phagocytosis of rod and cone outer segment fragments that are shed from their distal ends; the uptake, processing, transport and release of vit...

Vitamin A is essential for vision and the growth/differentiation of almost all human organs. Plasma retinol binding protein (RBP) is the principle and specific carrier of vitamin A in the blood. Here we describe an optimized technique to produce and purify holo-RBP and two real-time monitoring techniques to study the transport of vitamin A by the high-affinity RBP receptor STRA6. The first tech...

Human retinol-binding protein (RBP) and prealbumin were labeled with Z-hydroxy&nitrobenzyl bromide (HNB-Br) at pH 5.5 using 20to loo-fold molar excess of the label over tryptophan in each protein. In prealbumin, only 1 to 1.7 tryptophan residues out of 8 were modified under these conditions. This modification did not alter the capacity of prealbumin to bind to retinol-RBP at physiological ionic...

The fat-soluble vitamin A has, of necessity, to be transported in the body by carrier proteins since it functions in an aqueous environment. At the same time, control of the distribution of the alcohol form, via specific retinol-binding proteins (RBP), provides additional physiological advantages. The concentration of the amphiphilic molecule is more easily limited in tissue fluids where, if fr...

A fracture is a damage to bone tissue that causes the surrounding and may penetrate skin. Subjects methods: present study included (80) fractured Iraqi patients (and 40) with DM2 (40) without compared them healthy control. Patients control are matched in age. This showed significant increase retinol-binding protein 4 (RBP4) considerable decrease Vit .A GPT GOT DM2. In addition, there was negati...

Prealbumin was isolated from human plasma by chromatography on columns of diethylaminoethyl Sephadex and Sephadex G-200, followed by preparative polyacrylamide gel electrophoresis. The prealbumin was homogeneous in the analytical ultracentrifuge with an s=z~,~ of 3.7 S and with a molecular weight of about 50,000. Prealbumin formed a protein-protein complex with plasma retinol-binding protein in...

Human retinol-binding protein (RBP) and prealbumin were labeled with Z-hydroxy&nitrobenzyl bromide (HNB-Br) at pH 5.5 using 20to loo-fold molar excess of the label over tryptophan in each protein. In prealbumin, only 1 to 1.7 tryptophan residues out of 8 were modified under these conditions. This modification did not alter the capacity of prealbumin to bind to retinol-RBP at physiological ionic...