Phase-contrast light micrograph of human primary cells isolated from fresh urine in primary culture after 24 h in culture
(A). After, adhering to the collagen after 2–3 days, the cells are adhering to the collagen-I (B). Colonies of cells are formed after a week (C) and formed a confluent monolayer of cuboidal cells with cobblestone-like appearance. D: The cells after passage 2. Original magnification: ×20.