Base A chemical compound that either donates hydroxide ions or absorbs hydrogen ions when dissolved in water. Bases and acids are referred to as opposites because the effect of an acid is to increase the hydronium ion concentration in water, whereas bases reduce this concentration. Arrhenius bases are water-soluble and always have a pH greater than 7 in solution.
Hydrogen. The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight 1. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.
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Biological Marker of Aging
Any physiological marker that appears to be universal in an aging population.
Biological Response Modifier
Any molecule that can modify the biological response of cells to changes in its external environment.
The primary source of energy for the brain. Elevated blood glucose levels cause diabetes and accelerate aging.
The life-maintaining fluid which is made up of plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets; blood circulates through the body's heart, arteries, veins, and capillaries; it carries away waste matter and carbon dioxide, and brings nourishment, electrolytes, hormones, vitamins, antibodies, heat, and oxygen to the tissues.
Surgical removal of a piece of tissue from a person for microscopic examination to make a diagnosis (eg to determine whether abnormal cells such as cancer cells are present).
A hormone derived from the pituitary that induces opiate-like responses to decrease pain. The release of its precursor hormone (B-lipotropin) requires cyclic AMP.
Basal Cell Carcinoma
The most common non-melanoma skin cancer. It begins in the lowest layer of the epidermis, called the basal cell layer. It usually develops on sun-exposed areas, especially the head and neck. Basal cell cancer is slow-growing and is not likely to spread to distant parts of the body. A malignant skin neoplasm that seldom metastasizes but has potentialities for local invasion and destruction. Clinically it is divided into types: nodular, cicatricial, morphaic, and erythematoid (pagetoid). More than 95% of these carcinomas occur in patients over 40. They develop on hairbearing skin, most commonly on sunexposed areas. Approximately 85% are found on the head and neck area and the remaining 15% on the trunk and limbs.
Brain stem glioma
A tumor located in the part of the brain that connects to the spinal cord (the brain stem). It may grow rapidly or slowly, depending on the grade of the tumor.
A brain tumor is any mass created by an abnormal and uncontrolled growth of cells either found in the brain (neurons, glial cells, epithelial cells, myelin producing cells, etc.) or spread from elsewhere (metastasis). Brain tumors are usually located in the posterior third of the brain in childhood and in the anterior two-thirds of the brain in adulthood.
A malignant disease of breast tissue. Incidence increases with age and risk factors include a family history of breast cancer, late menopause, obesity, diabetes, and hypertension. Initial symptoms may include a small painless lump, thick or dimpled skin, or nipple retraction.
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