Larger view 438Kb brinfarc: This photograph of a slice of a brain shows an old, mostly cortical infarct on the left and a fresh, mostly cortical infarct on the right. Note the extensive loss of tissue on the left, and the dusky color of the white matter and the dark discoloration of the cortex on the right. Larger view 456Kb cortnec: This view of a longitudinal section of a kidney shows acute cortical necrosis, represented by the zones of pallor occupying most of the cortex. Larger view 299Kb egangren: This photo shows early or "wet" gangrene of the first and second toes. The necrotic tissue is moist and swollen. Larger view 422Kb gangren2: This picture shows fully developed "dry" gangrene of the first and fifth toes. The necrotic tissue is black and very firm. Larger view 380Kb gangrene: This striking picture shows coagulative necrosis of most of the patient’s left hand, an example of gangrene. Larger view 359Kb HbCAg(n): This is a micrograph showing immunoperoxidase staining for hepatitis B core antigen in the nuclei of liver cells in a patient who was infected with HIV. Larger view 480Kb HbCAg: This micrograph shows immunoperoxidase staining (the brown regions) for hepatitis B core antigen. Positive staining is seen in the cytoplasm of liver cells. Larger view 437Kb Inf: This micrograph shows irreversible cell injury in the heart (acute necrosis in a myocardial infarct). The nuclei of the muscle cells are not staining, and there are many polymorphonuclear neutrophils infiltrating the tissue, an acute inflammatory reaction. Larger view 2398Kb Liqnec: This picture shows a zone of remote necrosis in the basal ganglia (right side of picture) which has liquified and become a simple fluid-filled cyst. Larger view 247Kb LVH: This image of a cross section of the heart clearly shows left ventricular hypertrophy. The wall of the left ventricle is much thicker than normal. Larger view 354Kb LVHAS: This picture shows a side-by-side comparison between a heart with severe left ventricular hypertrophy (due to aortic stenosis) and a normal heart. Larger view 319Kb LVHdil: This picture shows side-by-side comparison of sections across the heart from a patient with left ventricular hypertrophy on the left, a normal heart in the middle, and a heart with left ventricular hypertrophy and dilation on the right. Although the thickness of the left ventricular wall is not thicker than normal, the mass of the left ventricle is greatly increased in the dilated heart. Larger view 570Kb LVHdilm: This microscopic view shows comparison of the microscopic appearance of the left ventricular muscle from the heart with hypertrophy on the left, the normal heart in the middle, and the heart with left ventricular hypertrophy and dilation on the right (as in the gross picture). Larger view 381Kb LVHht: This picture compares cross sections of the normal heart on the left and the heart with severe left ventricular hypertrophy on the right. Larger view 282Kb LVHm: This composite micrograph shows several features of the nuclei of heart muscle cells which have undergone hypertrophy, including enlargement, change in shape, and division (without cell division) to produce multiple nuclei. Larger view 444Kb MI: This picture illustrates the appearance of acute myocardial necrosis in a cross section of the left ventricle. Note the pale regions near the inner wall of the heart, which are often surrounded by red patches of hemorrhage. Larger view 440Kb OldMI: There is a region of pallor and scarring in the anterior left ventricular wall in this picture of a cross section of a heart. This is the site of an old, healed myocardial infarct. Larger view 251Kb OldMIthr: In this image, patchy regions of scar, representing the remains of an old infarct, are associated with a large, organizing mural thrombus in the left ventricle. Necrosis of muscle tissue has stimulated coagulation of blood. Such a mural thrombus could well be a source of systemic thrombo-emboli. Larger view 331Kb RVH: This picture nicely shows hypertrophy of the right ventricular wall and outflow tract compared to a similar cut of a normal heart. Larger view 229Kb Virhep: This micrograph shows an acidophilic body in the liver of a patient with chronic hepatitis. The cell marked by the arrowhead has undergone apoptosis.