Medical research

Mystery of resistance to malaria solved in new study

(Medical Xpress) -- Malaria is a disease caused by parasites passed to humans via the bites of infected mosquitoes. Globally, the disease causes over a million deaths every year, and is especially rife in parts of Africa ...

Diabetes

Researchers call for paradigm shift in type 2 diabetes treatment

Heart disease is a leading cause of death worldwide and exacerbated by type 2 diabetes, yet diabetes treatment regimens tend to focus primarily on blood sugar maintenance. This common approach to type 2 diabetes management ...

Medical research

An artificial blood substitute from Transylvania

(Medical Xpress)—Researchers in Cluj-Napoca, Romania, have recently made some significant advances in developing artificial blood substitutes. Their formulation is based not on synthetic hemoglobins, but rather on hemerythrin ...

Diabetes

Trends in insulin use, glycemic control explored

(HealthDay)—Since 1988, the proportion of patients with diabetes currently on any insulin has remained stable, according to research published online Dec. 30 in Diabetes Care.

Diabetes

Ranolazine added to glimepiride cuts HbA1c in T2DM

(HealthDay)—For patients with type 2 diabetes on background glimepiride therapy, but not metformin, addition of ranolazine is associated with a significant reduction in hemoglobin A1c (HbA1c), according to research published ...

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Hemoglobin

Hemoglobin (English pronunciation: /hiːməˈɡloʊbɪn/; also rendered as haemoglobin and abbreviated Hb or Hgb) is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates. Hemoglobin in the blood carries oxygen from the respiratory organs (lungs or gills) to the rest of the body (i.e., the tissues) where it releases the oxygen to burn nutrients to provide energy to power the functions of the organism, and collects the resultant carbon dioxide to bring it back to the respiratory organs to be dispensed from the organism.

In mammals, the protein makes up about 97% of the red blood cells' dry content, and around 35% of the total content (including water).[citation needed] Hemoglobin has an oxygen binding capacity of 1.34 ml O2 per gram of hemoglobin, which increases the total blood oxygen capacity seventy-fold compared to dissolved oxygen in blood. The mammalian hemoglobin molecule can bind (carry) up to four oxygen molecules.

Hemoglobin is involved in the transport of other gases: it carries some of the body's respiratory carbon dioxide (about 10% of the total) as carbaminohemoglobin, in which CO2 is bound to the globin protein. The molecule also carries the important regulatory molecule nitric oxide bound to a globin protein thiol group, releasing it at the same time as oxygen.

Hemoglobin is also found outside red blood cells and their progenitor lines. Other cells that contain hemoglobin include the A9 dopaminergic neurons in the substantia nigra, macrophages, alveolar cells, and mesangial cells in the kidney. In these tissues, hemoglobin has a non-oxygen-carrying function as an antioxidant and a regulator of iron metabolism.

Hemoglobin and hemoglobin-like molecules are also found in many invertebrates, fungi, and plants. In these organisms, hemoglobins may carry oxygen, or they may act to transport and regulate other things such as carbon dioxide, nitric oxide, hydrogen sulfide and sulfide. A variant of the molecule, called leghemoglobin, is used to scavenge oxygen, to keep it from poisoning anaerobic systems, such as nitrogen-fixing nodules of leguminous plants.

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