Hepatic ultrastructure in secondary syphilis

We describe the ultastructural findings in liver biopsy specimens from 19 patients with secondary syphilis. These patients were unselected, had negative tests for hepatitis B surface antigen, and were not jaundiced. Most hepatocytes appeared normal; a few showed minor nonspecific changes, including some prominence of lipofuscin. Kupffer cell and endothelial cell hyperplasia were noteworthy in some specimens, occasionally forming clusters with monomuclear cells. However, these findings, have no specificity. Although triponemes were seen in Warthin-stained sections by light microscopy in three instances, no organisms were detected in the blocks selected for electron microscopy.(AU)

Hepatic ultrastructure in congenital syphilis

The ultrastructural changes in the liver in a case of congenital syphillis were studied. Treponema organisms were easily demonstrated in 1-æm sections stained by toluidine blue, as well as in electron micrographs. Most organisms were extracellular, but some were identified within hepatocytes.(AU)

Scanning electron microscopy of proliferating bile ductules

Rats were subjected to ligation of the common bile duct to provoke bile ductular proliferation and were studied at intervals from 1 day to 6 weeks. After perfusion fixation with glutaraldehyde, and ethanol dehydration, blocks of liver were frozen in liquid nitrogen, fractured, and returned to ethanol prior to critical point drying. Examination with the scanning electron microscope showed a remarkable proliferation of bile ductules and preductules in addition to canalicular dilation. The ductules were surrounded by a longitudinal array of collagen fibers. The luminal surfaces contained many microvilli and cable-like structures, some identifiable as cilia by transmission electron microscopy. The present techniques offer the possibility for a reevaluation of obstructive jaundice and cholestasis.(AU)

Ultrastructural diagnosis of Gaucher's disease with negative-staining technique

The electron microscope provides easy confirmation in Gaucher's disease. This may be done with conventional ultrathin sections or, more quickly, by negative staining of tissues minced in 1 percent ammonium acetate. Typical helical structures associated with glucocerebroside storage were easily demonstrated with tissues that had been fixed in formaldehyde solution and embedded in paraffin blocks. Similar success was obtained with splenic tissue that had been in a museum jar for 17 years.(AU)

The protective effects of feeding on the hepatic ultrastructure of rats treated with hypoglycin

Hypoglycin is a toxic amino acid found in the fruit of the unripe ackee (Blighia sapida), and associated with Jamaican "vomiting sickness". It produces profound hypoglycaemia when administered to starved rats, and this is accompanied by gross mitochondrial swelling in liver cells. This ultrastructural change is reduced or absent in animals that have been allowed to feed ad libitum, provided that normal blood glucose levels are maintained. Mitochondrial swelling is not a feature of acute hypoglycaemia induced by insulin, under the conditions of this experiment.(AU)

Hypoglycin toxicity in rats. II. Modification by riboflavin of mitochondrial changes in liver

Hypoglycin (L-O-amino-á-methylenecyclopropanepropionic acid) is a toxin found in the unripe fruit of the ackee, and associated with Jamaican "vomiting sickness." It produces profound hypoglycemia due to interference with long-chain fatty acid oxidation and gluconeogenesis, and is accompanied by mitochondrial swelling in rat hepatocytes. The hypoglycemic effect may be prevented or reversed by riboflavin. The present study indicates that mitochondrial swelling is reduced in rats given riboflavin prior to hypoglycin, compared with rats given hypoglycin alone. Riboflavin appears less effective if given 10 minutes after hypoglycin.(AU)

Acute veno-occlusive disease of the liver: fine structure in Jamaican children

Electron microscopic observations in humans veno-occlusive disease (VOD) of the liver are presented for the first time . Marked endothelial damage was seen in the sinusoids and subterminal and terminal hepatic veins, accompanied by extravasation of erthrocytes into Disse's space and naked hepatocytes showing a reduction in microvilli. Endothelial damage was seen in all zones of the liver. At the level of terminal hepatic veins, the closed structure of these vessels, absence of fenestrations, existence of a basement membrane, and the presence of collagen and connective tissue cells in the wall provide resistance to erthrocytes and cellular debris tracking up Disse's space. These factors tend to result in narrowing of the lumen where the sinusoid enters the vein. Parenchymal cell alterations, at the time of the biopsies, included dilation of bile canaliculi, abundant glycogen, and nuclear invaginations.(AU)

Studies on hypoglycin toxicity in rats. I. Changes in hepatic ultrastructure

Hypoglycin is a toxic amino acid found in the unripe ackee fruit. The ackee is a popular item of diet in Jamaica and has been proposed as a cause of the so-called vomiting sickness. Hypoglycin is thought to act by inhibiting the oxidation of long-chain fatty acids, uncoupling oxidative phosphorylation, and interfering with gluconeogenesis. Hypoglycin was given intraperitoneally to rats in a dose of 10 mg/100 g, and samples of liver taken at hourly intervals up to 5 hr were studied with the electron microscope and compared with controls. The major ultrastructural findings in the hypoglycin-treated rats were progressive mitochondrial swelling with loss of granules and pallor of the matrix, followed by incorporation into autophagic vacuoles. These findings correlate well with the reported biochemical mechanisms.(AU)

Electron microscopy of giardia lamblia in human jejunal biopsies

A description is given of the ultrastructure of Giardia lamblia found in three jejunal biopsies from children. The unique median body, vacuoles and cytoplasmic clefts of this protozoon are illustrated. No evidence of penetration of the trophozoite into the jejunal mucosa or deeper tissues is demonstrable.(AU)

Acute effects of hypoglycin on the fine structure of rat's liver - abstract

The acute effects of hypoglycin on the rat's liver were studied by light and electron microscopy. After a starvation period of 18 hours, male Charles River rats were given intraperitoneal hypoclycin (10 mg/100 g). Groups of animals were sacrificed at hourly intervals to 5 hours. Other groups of rats were given 2.5 mg riboflavin prior to hypoglycin, riboflavin after hypoglycin, or riboflavin alone. A control group received 1 ml/100 g of 0.9 percent saline. The most pronounced change observed in animals given hypoglycin was that the mitochondria showed progressive loss of granules, reduction of density of the matrix and swelling, and incorporation into cytolysosomes. This correlates well with the biochemical observations of von Holt that long-chain fatty acids accumulate in the mitochondria and that oxidative phosphorylation is uncoupled(AU)