Focal fatty

Under physiologic conditions, the balance of membrane lipid metabolism, particularly that of arachidonoyl and docosahexaenoyl chains, favors a very small and tightly controlled cellular pool of free arachidonic acid (AA, 20 4n-3) and docosahexaenoic acid (DHA, 22 6n-3), but levels increase very rapidly upon cell activation, cerebral ischemia, seizures and other types of brain trauma [1, 2], Other free fatty acids (FFAs) in addition to AA, released during cell activation and the initial stages of focal and global cerebral ischemia, are stearic acid (18 0), palmitic acid (16 0) and oleic acid (18 1). 

This MRL for mirex was derived using a NOAEL of 0.075 mg/kg/day for dose-dependent hepatic changes from a study by NTP (1990). The dose-dependent changes included increased fatty metamorphosis (cytoplasmic vacuoles consistent with intracellular fat accumulation) and necrosis of hepatocytes (focal and/or centrilobular) in F344/N rats of both sexes at a dose of 0.7 mg/kg/day... 

Livers from toxin-injected mice showed severe congestion whether or not the mice survived the initial critical 2-hour post injection period. Occasionally, a mouse injected with a nominally lethal dose of toxin-LR survived the critical two hours but remained listless until it died several hours or several days later. The reasons for the delayed death are unknown. Such mice developed focal fatty degeneration of the liver and active regeneration of liver cells. 

After a single exposure of rabbits to 17 ppm for 6 hours, the sensory trigeminal nucleus was severely affected. Other effects included tubular and focal necrosis in the collecting tubules of the kidney and fatty degeneration of the liver. ... 

Like many volatile halocarbons and other hydrocarbons, inhalation exposure to carbon tetrachloride leads to rapid depression of the central nervous system. Because of its narcotic properties, carbon tetrachloride was used briefly as an anesthetic in humans, but its use was discontinued because it was less efficacious and more toxic than other anesthetics available (Hardin 1954 Stevens and Forster 1953). Depending on exposure levels, common signs of central nervous system effects include headache, giddiness, weakness, lethargy, and stupor (Cohen 1957 Stevens and Forster 1953 Stewart and Witts 1944). Effects on vision (restricted peripheral vision, amblyopia) have been observed in some cases (e.g., Johnstone 1948 Smyth et al. 1936 Wrtschafter 1933), but not in others (e.g., Stewart and Wtts 1944). In several fatal cases, microscopic examination of brain tissue taken at autopsy revealed focal areas of fatty degeneration and necrosis, usually associated with congestion of cerebral blood vessels (Ashe and Sailer 1942 Cohen 1957 Stevens and Forster 1953). 

The G5 and G6 dendrons did not assemble into monolayers because of the tendency of the focal point to be encapsulated by the hydrophobic dendritic branches at higher generations. Similarly, Liskamp s group reported a series of amino acid based dendrons capped with Boc end groups and a focal fatty acid chain also formed stable monolayers however, the fatty acid group was not a significant improvement over a shorter linkage (Mulders et al. 1998). In the condensed mono-layer phase, the dendrons covered a smaller area than predicted for a fully spread... 

Zhang J. P. and Sun G. Y. (1995). Free fatty acids, neutral glycerides, and phosphoglycerides in transient focal cerebral ischemia. J. Neurochem. 64 1688-1695. 

Ruse M, Broome AM, Eckert RL. 2003. S100A7 (psoriasin) interacts with epidermal fatty acid binding protein and localizes in focal adhesion-like structures in cultured keratinocytes. J Invest Dermatol 121(1) 132—141. 

The parathyroid glands have, naturally, been carefully studied but have always been found to be normal. The liver has been noted to be the subject of fatty changes and centrilobular focal necrosis. In some cases the lungs have shown evidence of terminal bronchopneumonia or purulent bronchiolitis. Other organs have usually appeared normal. 

Rat 15 Inhalation 660 90 d, continuous 13 of 15 animals died. Histopathologic examination revealed focal or diffuse interstitial pneumonitis, calcification of renal tubules, calcification of bronchial epithelial, renal tubular epithelial proliferation, myocardial fibrosis fatty changes of the liver in several animals. Changes were also found in control animals, but were of lesser seventy. LOAEL 660 Goon et al. 1970... 

Benzene is metabolized primarily in the liver by the cytochrome P-450 system (Parke 1989). It appears that the metabolism of benzene by the hepatic cytochrome P-450 system plays an important role in its bioactivation and toxicity. Sammett et al. (1979) provided corroborative evidence of this by showing that partial hepatectomy of rats diminished both the rate of metabolism of benzene and its toxicity. An increase in altered hepatic foci has been shown in male rats after benzene exposure in conjunction with initiator and promotor administration (Dragan et al. 1993). A dose of 500 mg/kg of benzene administered subcutaneously once daily, 5 days a week for 26 weeks to Wistar rats resulted in focal fine droplet fatty metamorphosis with accompanying lymphoidal infiltration in the liver after 12 weeks (Bloch et al. 1990). In some cases a proliferated histocyte-like cells formed clusters in the vicinity of the periportal fields. After 26 weeks, more diffuse steatosis, feathery degeneration of hepatocytes, single necrotic cells were seen. 

The following lesions may be hypoechoic (7.) metas-tases, (2.) liver cell carcinoma, (3.) adenomas, (4.) focal nodular hyperplasia, (5.) abscesses, (6.) haematomas, (7.) early liver infarction, (S.) foci showing reduced fatty infiltration, (9.) lymphomas, and (10.) lipomas. In individual cases, differentiation between a benign and a malignant structural defect may cause considerable difficulties. (59) (s. fig. 9.4)... 

Fig. 6.12 Focal reduction of fat in a fatty Uver hypoechoic, triangular shape (see arrow) near to the right branch of the portal vein (PV) and the gall bladder (GB) (VC = inferior vena cava)...

Fig. 6.13 Focal reduction of fat in a fatty liver hypoechoic round shape (see arrows)...

Fig. 8.3 Pronounced focal (regional) fatty degeneration of the hver of varying intensity both visual and confirmed by Hounsfield units (-14, -9, +4, +30). Native CT, normal value +65 HU...

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