Dihydrorhodamine 123 (DHR123) is an uncharged non-fluorescent dye and a derivative of rhodamine 123 (R123). Dihydrorhodamine 123 (DHR123) is oxidized to fluorescent R123 within cells in the presence of reactive oxygen species and it localizes in mitochondria.
What is dihydrorhodamine?
Dihydrorhodamine 123 is an uncharged and nonfluorescent reactive oxygen species (ROS) indicator that can passively diffuse across membranes where it is oxidized to cationic rhodamine 123 which localizes in the mitochondria and exhibits green fluorescence.
How does the dihydrorhodamine test work?
The DHR (dihydrorhodamine) (flow cytometry test) and NBT (nitroblue tetrazolium) tests are used to diagnose CGD. Both work in a similar way. They check if someone’s blood cells are producing the enzyme NADPH oxidase, which plays a vital role in the way white blood cells fight infection.
What does reactive oxygen species do?
A type of unstable molecule that contains oxygen and that easily reacts with other molecules in a cell. A build up of reactive oxygen species in cells may cause damage to DNA, RNA, and proteins, and may cause cell death. Reactive oxygen species are free radicals.
What is a DHR test?
Dihydrorhodamine (DHR) test. This flow cytometric test is now widely and commercially available and should be considered the preferred screening and diagnostic test for chronic granulomatous disease. This test should be considered the most accurate diagnostic test for chronic granulomatous disease.
What is CGD?
Chronic granulomatous disease (CGD) is a genetic disorder in which white blood cells called phagocytes are unable to kill certain types of bacteria and fungi. People with CGD are highly susceptible to frequent and sometimes life-threatening bacterial and fungal infections.
What is the DHR test?
The DHR test is also referred to as the neutrophil oxidative burst (NOXB1) assay for assessing neutrophil superoxide production.
How is CGD detected?
Your doctor may order several tests to diagnose CGD , including: Neutrophil function tests. Your doctor may conduct a dihydrorhodamine 123 (DHR) test or other tests to see how well a type of white blood cell (neutrophil) in your blood is functioning. Doctors usually use this test to diagnose CGD .
What is a DHR blood test?
The dihydrorhodamine, or DHR, test, is a blood test used to test for chronic granulomatous disease, CGD. It can also detect the type of CGD or carrier status. The DHR Collection Kit is used to collect and ship blood samples to be tested for CGD using the DHR test.
Is hydrogen peroxide a ROS?
Among the ROS generated are hydrogen peroxide (H2O2), hypochlorite (HOCl), hydroxyl, and superoxide (O2−). These oxidants can induce injury in a variety of mammalian cells, including endothelial cells (ECs). Although O2− can be directly toxic, it has limited reactivity with most biological molecules.
What increases ROS?
The production of ROS is strongly influenced by stress factor responses in plants, these factors that increase ROS production include drought, salinity, chilling, defense of pathogens, nutrient deficiency, metal toxicity and UV-B radiation.
Is CGD fatal?
Survival rates are variable but improving; approximately 50% of patients survive to age 30-40 years. Infections are less common in adults than in children, but the propensity for severe life-threatening bacterial infections persists throughout life.
What is the role of DHR 123 in rhodamine synthesis?
In the presence of 10 μM Dihydrorhodamine 123 (DHR 123) the stimulation of the neutrophil NADPH oxidase by the addition of 50 nM phorbol 12-myristate 13-acetat (PMA) resultes in an increase in the rate of rhodamine generation.
What is the structure of dhr123?
DHR123 is also a nonfluorescent molecule that diffuses across cell membranes based on its lipophilicity. The molecule is oxidized to the fluorescent rhodamine123 (λexcitation 505 nm and λemission 529 nm) and is trapped within cells in this form.
What is the fluorescence of rhodamine dye?
Rhodamine is a generic term for a wide variety of cationic dyes whose fluorescence emission can range from green, orange to red. The table below lists the excitation and emission maxima (nm), as well as molar extinction coefficients (“EC”; cm -1 M -1 ), for various rhodamine dyes (data derived with dye dissolved in methanol).
How do you load mitochondria with dihydrorhodamine 123?
Cells or mitochondria are loaded at room temperature for 5 min with 0.1 μM dihydrorhodamine 123 (DHR; Molecular Probes, Eugene, OR). Flow cytometry is performed with excitation of the mitochondria at 488 nm and emission at 525 nm.
