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Abstract. This article describes the gross, histopathologic, and ultrastructural findings of the livers of cetaceans stranded on the coast of the Canary Islands between 1992 and 2000. A total of 135 cetaceans were included in the study, among which 25 were common dolphins (Delphinus delphis), 23 Atlantic spotted dolphins (Stenella frontalis), 19 striped dolphins (Stenella coeruleoalba), and 15 other species of dolphins and whales. The most common lesion observed in these animals was a nonspecific chronic reactive hepatitis (47/135), followed by hyaline intracytoplasmic inclusions in hepatocytes (33/135). Parasitic cholangitis was detected in 8/135 animals, whereas hepatic lipidosis was presented in 7/135 animals. The ultrastructure of hyaline hepatocytic cytoplasmic inclusions is described, and possible causes of these inclusions are discussed.Key words: Cetaceans; dolphins; hepatic lesions; liver; ultrastructure.Information on cetaceans found stranded on the coast of the Canary Islands has been collected by the Histology and Pathology Unit of Las Palmas of Gran Canaria University during an 8-year period (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000). One hundred and thirty-five cetacean strandings occurred on the shores of these islands, involving both single and multiple strandings of adults and juvenile cetaceans, but to date there have been no surveys of the causes of illness in the wild, free-living dolphin and whales found dead in the Canary Islands.In the study of the stranded cetaceans, the liver, as in other studies, 2,12,13 was extensively analyzed and a variety of lesions that merited further investigation were found. Chronic liver disease of unknown cause is a common ailment in dolphins and is clinically characterized by wasting but is rarely characterized by jaundice. Hepatic lesions consist of hepatocyte degeneration, fatty change, and fibrosis. 33 Chronic liver disease is generally regarded as being nutritional in origin, but there is no definite evidence to support this. 19,33 Different types of acute hepatitis associated with nutritional or environmental toxins and biologic agents, such as viruses, bacteria, fungi, and parasites, have also been reported in stranded dolphins. 30 Parasitic infections have been recognized amongst the pathologic changes found in marine mammals. 34 Campula spp. is a common trematode that primarily inhabits the bile and pancreatic ducts, stomach, and intestine of cetaceans. 36 Affected ducts are dilated, fibrosed, and infiltrated with mononuclear cells, and the epithelium is hyperplastic. 8,27 Dolphins, as other cetaceans, are at the top of the marine food chain, and they accumulate pollutants in their tissues during their life. Therefore, this species is an excellent bioindicator to evaluate contamination of the marine environment. Numerous studies have been carried out to analyze concentrations of pollutants in dolphins from different areas of the world. 1,[4][5][6]16 Despite some studies that have described hepatic lesions in stranded dolphins, 2,9,12,22,29...

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Abstract. Liver cytology was evaluated in 28 healthy dogs 1-14 years of age with normal liver structure and function. Smears were stained with May-Grünwald-Giemsa. Hepatocytes had distinct cell borders, and cells did not overlap. Cells with two nuclei and cells with intranuclear crystalloid structures were observed regularly. Cytoplasm contained small numbers of vacuoles characteristic of glycogen and lipid and small amounts of pigment consistent with ceroid or bile. Nuclei were uniform. Small numbers of biliary epithelial cells were seen in most samples. Lymphocytes and neutrophils occurred in small numbers, with lipocytes, mast cells, fibrocytes, mesothelial cells, eosinophils, and Kupffer macrophages seen less frequently. Mean parenchymal cell sizes were significantly greater in older dogs, but no age-related differences were observed in nuclear size. Older dogs also had a significantly increased number of nuclei per cell. There were more neutrophils in young and old dogs than in middle-aged dogs.