Cellular atrophy

Liver biopsies have been performed in some patients with chronic vitamin A intoxication. Perisinusoidal fibrosis and massive accumulation of lipid-storing cells were found. Impairment of blood flow by perisinusoidal fibrosis probably resulted in secondary alterations in hepato-cytes, including cellular atrophy and formation of cytoplasmic bullae. Histological examination also showed central vein sclerosis and focal congestion associated with perisinusoidal storage. The vitamin A concentration in the liver was increased (40-42). 

AD is a neuronal degenerative process that is characterized by the presence of NFTs, neuritic plaques, and cellular atrophy in the cortex and limbic structures of the brain. Though the presence of these structural changes are the hallmark of definitive AD diagnosis, the initial precipitating event remains uncertain. 

Leukopenia has been the first manifestation to appear within the first days of postexposure. Thrombocytopenia and anemia followed later if the patients survived (WBCs of some patients dropped to less than 1,000 per cm ). Although most of these patients suffered skin bums, clinicians reported cases that had minor skin lesions and yet developed leukopenia. Bone marrow biopsies revealed hypocellular marrow and cellular atrophy involving all elements (Willems, 1989). Studies on the status of immimocompetent cells in the blood of patients exposed to HD showed that T cell... 

There are hundreds of topical steroid preparations that are available for the treatment of skin diseases. In addition to their aforementioned antiinflammatory effects, topical steroids also exert their effects by vasoconstriction of the capillaries in the superficial dermis and by reduction of cellular mitosis and cell proliferation especially in the basal cell layer of the skin. In addition to the aforementioned systemic side effects, topical steroids can have adverse local effects. Chronic treatment with topical corticosteroids may increase the risk of bacterial and fungal infections. A combination steroid and antibacterial agent can be used to combat this problem. Additional local side effects that can be caused by extended use of topical steroids are epidermal atrophy, acne, glaucoma and cataracts (thus the weakest concentrations should be used in and around the eyes), pigmentation problems, hypertrichosis, allergic contact dermatitis, perioral dermatitis, and granuloma gluteale infantum (251). 

Pieters RHH, Bol M, Seinen W (1994a) Cellular and molecular aspects of organotin-induced thymus atrophy. Human and Experimental Toxicology, 13(12) 876-879. 

Manson-Smith, D.F., Bruce, R.G. and Parrot, D.M.V. (1979) Villus atrophy and expulsion of intestinal Trichinella spiralis are mediated by T cells. Cellular Immunology 47, 285-293. 

Atrophy of the thymus is a consistent finding in mammals poisoned by 2,3,7,8-TCDD, and suppression of thymus-dependent cellular immunity, particularly in young animals, may contribute to their death. Although the mechanisms of 2,3,7,8-TCDD toxicity are unclear, research areas include the role of thyroid hormones (Rozman et al. 1984) interference with plasma membrane functions (Matsumura 1983) alterations in ligand receptors (Vickers et al. 1985) the causes of hypophagia (reduced desire for food) and subsequent attempts to alter or reverse the pattern of weight loss (Courtney et al. 1978 Seefeld et al. 1984 Seefeld and Peterson 1984) and excretion kinetics of biotransformed metabolites (Koshakji et al. 1984). 

Utilize an in vivo bone marrow-thymus reconstitution model and mouse strains with arrested T-cell development to define the cellular and molecular targets of 2,3,7,8-TCDD that lead to thymic atrophy, and determine how these events relate to its overall action on the immune system. Dr. Gasiewicz is also determining what controls the functional activity of the Ah receptor, what target genes are affected in sensitive tissues, and how the modulated expression of these genes leads to the toxic responses observed after exposure to... 

Atrophy Reduction in size of a structure or organ resulting from lack of nourishment or functional activity, death and reabsorption of cells, diminished cellular proliferation, ischemia, or hormone changes. 

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