Biochemical Manifestations of Hypoxia

The delivery of oxygen to the cells of tissues is a function of hemoglobin concentration, hematocrit, oxygen content of the red cells, extraction of oxygen by the tissues, and metabolism by intervening cells (10).Erythropoiesis is a process involving cell divisions followed by a loss of nuclei, mitochondria, and ribosomes. An important aspect of this process is protein synthesis, particularly globin. A known regulatory mediator of erythropoiesis is erythropoietin (Epo), which is produced mostly in the kidneys; a principal stimulus for this synthesis is tissue hypoxia. An increase in erythrocytes production by bone marrow, leading to an increase in red cell mass, is found in chronic hypoxic conditions such as high altitudes. This is not a beneficial process. Studies with human subjects are limited; predominant erythroid cells found in the bone marrow associated with chronic hypoxia are normoblasts (advanced degree of differentiation).

Pinder and Smits report that increases in hematocrit (a tube with graded markings used to determine the volume of packed red cells in a blood specimen by centrifugation) are found in h

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gger elevations in intravascular pressure as an adaptory mechanism. Infants weighing less than 1,500 g at birth demonstrate a 25 percent occurrence of periventricular (PVH) and intraventricular (IVH) hemorrhages. Phenobarbital and other barbiturates are used to reduce physiological responses involved in the pathogenesis of IVH and PVH; they have been found to decrease cerebral blood flow, metabolic activity and the cerebral metabolic rate of oxygen in a dose-dependent manner. In animals, barbiturates have been found to be neuroprotective after hypoxic ischemic insults. Clinical effects of barbiturates in newborns also reported after an asphyxic episode result in reduced frequency on intraventricular hemorrhages (3). Oxygen & Tumors Stone, Brown, Phillips, and Sutherland report that hypoxia can affect gene amplification and malignant aggression. Oxygenation of human tumors is important in response to radiotherapy. Cellular radiosensitivity and binding of nitroimidazoles demonstrate dependence on oxygen concentrations in the cell environment; compounds reach hypoxic cells easily since they are consumed by tissue less rapidly than oxygen. Oxygen levels in human tumors need to be measured because the presence of hypoxia prior t
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Some common words found in the essay are:
Morita Kourembanas, Wypij Volpe, Conclusion Hypoxic, Oxygen Erythropoiesis, Abugo Rifkind, Meynier Bonne, Phillips Sutherland, Ohta Okada, Hamon Vert, IVH PVH, smooth muscle, bone marrow, hypoxic conditions, vascular smooth muscle, vascular smooth, muscle cells, smooth muscle cells, production bone marrow, production bone, cerebral oxygen, vascular tone, endothelial permeability, tone endothelial permeability, tone endothelial, cerebral oxygen supply,
Approximate Word count = 1554
Approximate Pages = 6 (250 words per page)