Biochemistry and Molecular Biology Developmentally Regulated Production of meso- Zeaxanthin in Chicken Retinal Pigment Epithelium/ Choroid and Retina

PURPOSE. meso-Zeaxanthin is a carotenoid that is rarely encountered in nature outside of the vertebrate eye. It is not a constituent of a normal human diet, yet this carotenoid comprises onethird of the primate macular pigment. In the current study, we undertook a systematic approach to biochemically characterize the production of meso-zeaxanthin in the vertebrate eye. METHODS. Fertilized White Leghorn chicken eggs were analyzed for the presence of carotenoids during development. Yolk, liver, brain, serum, retina, and RPE/choroid were isolated, and carotenoids were extracted. The samples were analyzed on C-30 or chiral HPLC columns to determine the carotenoid composition. RESULTS. Lutein and zeaxanthin were found in all studied nonocular tissues, but no mesozeaxanthin was ever detected. Among the ocular tissues, the presence of meso-zeaxanthin was consistently observed starting at embryonic day 17 (E17) in the RPE/choroid, several days before its consistent detection in the retina. If RPE/choroid of an embryo was devoid of mesozeaxanthin, the corresponding retina was always negative as well. CONCLUSIONS. This is the first report of developmentally regulated synthesis of mesozeaxanthin in a vertebrate system. Our observations suggest that the RPE/choroid is the primary site of meso-zeaxanthin synthesis. Identification of meso-zeaxanthin isomerase enzyme in the developing chicken embryo will facilitate our ability to determine the biochemical mechanisms responsible for production of this unique carotenoid in other higher vertebrates, such as humans

Lutein, zeaxanthin, and meso-zeaxanthin: The basic and clinical science underlying carotenoid-based nutritional interventions against ocular disease

Pušenje je štetna navika raširena među svim slojevima pučanstva. Smatra se rizičnim čimbenikom za zdravlje koji dovodi do prijevremenog umiranja. Duhanski dim sadrži više od četiri tisuće sastojaka koji djelujući podražajno, toksično, kancerogeno i psihoaktivno remete funkcije pojedinih organa. Ne postoji ni jedan organ ili organski sustav koji nije zahvaćen štetnim učincima pušenja. U ovom radu opisano je djelovanje duhanskog dima na krvožilni, dišni i probavni sustav. Također su spomenute i opasnosti pasivnog pušenja. Naglašena je važnost zdravstvenog odgoja te su razrađene metode zdravstvenog odgoja kojima se ovisnicima o pušenju nastoji promijeniti štetno zdravstveno ponašanje. Posebno je naglašena važnost medicinske sestre koja svojim znanjem i osobnim primjerom ima veliki utjecaj na smanjenje uporabe duhana kod pojedinca i zajednice. Opisan je pristup medicinske sestre kod određenih skupina kao što su trudnice, djeca i mladi te starije osobe.Smoking is a harmful habit widespread among all sections of the population. It is considered a risk factor for health leading to premature death. Tobacco smoke contains more than four thousand ingredients that have an irritant, toxic, carcinogenic and psychoactive effect on the functions of individual organs. There is no organ or organ system that is not affected by the harmful effects of smoking. This paper describes the effect of tobacco smoke on the circulatory, respiratory and digestive systems. The dangers of secondhand smoke were also mentioned. The importance of health education is emphasized and methods of health education that seek to change addictive behaviors are elaborated. Particular emphasis is placed on the importance of the nurse, who with her knowledge and personal example has a great influence on reducing the use of tobacco in individuals and in the community. The approach of the nurse to specific groups such as pregnant women, children and young people and the elderly is described

Membrane cholesterol regulates TRPV4 function, cytoskeletal expression, and the cellular response to tension

Despite the association of cholesterol with debilitating pressure-related diseases such as glaucoma, heart disease, and diabetes, its role in mechanotransduction is not well understood. We investigated the relationship between mechanical strain, free membrane cholesterol, actin cytoskeleton, and the stretch-activated transient receptor potential vanilloid isoform 4 (TRPV4) channel in human trabecular meshwork (TM) cells. Physiological levels of cyclic stretch resulted in time-dependent decreases in membrane cholesterol/phosphatidylcholine ratio and upregulation of stress fibers. Depleting free membrane cholesterol with m-β-cyclodextrin (MβCD) augmented TRPV4 activation by the agonist GSK1016790A, swelling and strain, with the effects reversed by cholesterol supplementation. MβCD increased membrane expression of TRPV4, caveolin-1, and flotillin. TRPV4 did not colocalize or interact with caveolae or lipid rafts, apart from a truncated ∼75 kDa variant partially precipitated by a caveolin-1 antibody. MβCD induced currents in TRPV4-expressing Xenopus laevis oocytes. Thus, membrane cholesterol regulates trabecular transduction of mechanical information, with TRPV4 channels mainly located outside the cholesterol-enriched membrane domains. Moreover, the biomechanical milieu itself shapes the lipid content of TM membranes. Diet, cholesterol metabolism, and mechanical stress might modulate the conventional outflow pathway and intraocular pressure in glaucoma and diabetes in part by modulating TM mechanosensing