Perls reaction - histochemistry of iron in liver

Uloga željeza u organizmu je jako bitna i raznolika. Željezo je esencijalni element i možemo ga podijeliti na hemsko i nehemsko. Pojam nehemsko željezo podrazumijeva heterogene vrste željezovih kompleksa u kojima je željezo slabo vezano na organske baze i proteine niske molekulske mase, za razliku od hemskog željeza gdje je taj element vezan na protoporfirinski prsten velike molekulske mase. Za histokemiju nehemskog željeza otopljenog u kiseloj otopini koriste se dvije histokemijske metode: Perlova i Turnbull metoda te i druge metode koje koriste kelatore željeza i ovise o stvaranju netopivih čestica željeza. Najčešće korištena u laboratorijima je Perlova metoda i njome se mogu dokazati i fero i feri ioni željeza, dok je Turnbull metoda specifična samo za fero ione. Međutim, perfuzijom Turnbull metode in vivo može se jasno pokazati distribucija feri željeza, osobito u lizosomima. Za elektronsku mikroskopiju Perlova i Turnbull reakcija se mogu pojačati DAB/ srebro/ zlato metodom da bi vizualizacija željeza bila što bolja, te se primjenjuju i željezo sulfid metoda kao i bojenje redox–aktivnog željeza vodikovim peroksidom ili DAB-om. Unatoč svim prednostima opisanih metoda, kvantitativna mjerenja željeza u pojedinim uzorcima su dosta komplicirana i teško izvediva. Danas se za kvantitativnu procjenu kelatirajućeg Fe2+ najboljom pokazala metoda zasnovana na suzbijanju flourescencije indikatora metala ( PG , SK, rodaina, kalceina, ...) te na njenom ponovnom uspostavljanju poznatim količinama različitih kelatora dvovalentnih metala, opisana u poglavlju 5.2. Sve spomenute metode imaju veliku ulogu u dijagnosticiranju različitih poremećaja i oštećenja tkiva.The role of iron in the body is very important and diverse. Iron is an essential element and we can devide it on hem and nonheme iron. The term nonheme iron includes heterogeneous types of complexes in which iron is loosely bound to low-molecular weight organic bases and proteins, unlike hem iron where this element is linked to the high molecular weight protoporphyrin ring. For histochemistry of nonheme iron dissolved in acid solution , in use are two histochemical methods: Perls and Turnbull method and other methods using iron chelators and dependent on the creation of insoluble particles of iron. The most commonly used in laboratories is a Perls method and it stains ferrous and ferric iron ions, while the Turnbull method is specific only to ferrous ions. However, perfusion Turnbull methods in vivo can clearly demonstrate the distribution of ferrous iron, particularly in the lysosomes. For electron microscopy Perls and Turnbull reactions are enhanced by DAB / silver / gold method for better visualization and iron sulfide staining methods as well as redox-active iron with hydrogen peroxide or DAB-om are also applicable for electon microscopy. Despite all the advantages of the described methods, quantitative measurements of iron in some samples are quite complicated and difficult feasible. Today, for the quantitative assessment of chelating Fe2 + showed the best method based on quenching fluorescence metal indicators (PG, SG, rodaina, kalceina, ...) and its dequenching of the known quantities of various divalent metal chelating treatment, described in section 5.2. All these methods have an important role in the diagnosis of various disorders and tissue damage