Microsomal lipid peroxidation: morphological characterization.

Lipid peroxidation of liver and kidney microsomes induces a highly characteristic sequence of morphological changes typified by detachment of ribosomes and formation of large aggregates of vesicles bound together by dense amorphous material and myelin figure-like debris. The trilaminar structure of the membrane is, however, retained even after complete peroxidation, though its spacing may be increased. The aggregates resemble lysosomal lipofuscin pigment as well as the membranous aggregates of endoplasmic reticulum seen in the liver after carbon tetrachloride poisoning.

Elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxine in goat milk.

2,3,7,8-Tetrachlorodibenzo-p-dioxine (TCDD) 200 ng/day, was given orally to 7 goats for 2 months, followed by an elimination period of 1 month. Then a daily dose of 400 ng TCDD was given for 1 month to the same animals. Two animals were killed and the rest of the animals were observed for several months. The excretion of TCDD in milk was studied by glass capillary gas fragmentography, where the minimal detectable concentration was below 5 ppt. After the first feeding the concentration of TCDD in milk achieved a maximum of 20.8 +/- 6.6 ppt while a similar value of 19.3 +/- 6.6 ppt was observed after the second feeding. After this period, the concentration of TCDD decreased slowly with values, after 18 weeks, of 4, 2 +/-, 3 and 6 ppt. The concentration of TCDD in the liver in the two animals killed was 1039.0 and 898.0 ppt. There were no differences in clinical observations or blood and urine analyses when experimental animals were compared with controls.

Studies on vinblastine-induced autophagocytosis in the mouse liver.I. The relation of lysosomal changes to general injurious effects.

Intraperitoneal injection of two doses of vinblastine (10 mg/kg and 50 mg/kg) induced a prominent formation of autophagic vacuoles in mouse liver parenchymal cells in 4 h. Clearly recognizable organelles were seen inside these vacuoles. The amount of autophagy was dependent on doses in that autophagosomes almost disappeared within 12 h with the low dose, whereas with the high dose the -ells were filled with residual bodies. Defecation of lysosomal material was ovserved into the sinusoidal lumen 12 h after injection with high dose. The total activities of lysosomal enzymes acid phosphatase, beta-galactosidase, and beta-acetylglucosaminidase did not change in the liver after vinblastine administration. The soluble activities of beta-galactosidase and beta-glucosaminidase were elevated with the high dose 12 h after injection, indicating labilization of the lysosomal membranes. Simultaneously the activities of the three lysosomal enzymes were elevated in the serum. The injurious effect of VBL appeared in light-and electron microscopic levels indicating diffuse necrosis of the liver lobules with the high gose within 12 h, fat accumulation in the cells, accumulation of secretory vesicles containing very low density lipoprotein particles, partial dilatation, vesiculation of endoplasmic reticulum and dilatation of Golgi cisternae. The serum GOT and CPK levels were also elevated

Pulmonary deposits of titanium dioxide in cytologic and lung biopsy specimens. Light and electron microscopic x-ray analysis.

Although titanium dioxide (TiO2) is widely used in industry, its biologic effects have not been determined. In the present investigation, open lung biopsy samples and sputum specimens from three former TiO2 factory workers and bronchial aspirations from seven TiO2 factory workers were analyzed by conventional and x-ray microanalytic light and electron microscopic methods. These studies showed that in the alveolar macrophages, lysosomes contained a significant amount of titanium as well as smaller amounts of silicon, aluminum, iron, and potassium. It appeared that titanium dioxide was situated in round or oval-shaped particles whereas silica or silicon compounds were localized in separate, more rectangular structures. There fore, the adverse effects may be induced by such quartz or silicon compounds. The latter are utilized as covering substances in the manufacture of TiO2 pigment.

Vitamin E deficiency and the susceptibility to lipid peroxidation of mouse cardiac and skeletal muscles.

Effects of a short-term vitamin E deficiency on some lipid peroxidative properties were investigated in mouse cardiac and skeletal muscles. The concentration of vitamin E decreased 35.8% in 5 weeks and 61.2% in 12 weeks in skeletal muscle. The corresponding decrease in cardiac muscle was 65.7% in 12 weeks. Simultaneously the susceptibility of muscle homogenates to in vitro lipid peroxidation increased with 48.6% (5 weeks) and 44.5% (12 weeks) in skeletal muscle and with 101.8% (12 weeks) in cardiac muscle. Highly significant negative correlations were observed between the concentration of vitamin E and in vitro lipid peroxidation in cardiac and skeletal muscles. Also the sensitivity to Fe2+-induced peroxidation was increased in skeletal muscle after the deficiency of 5 weeks. The total contents of peroxidizable lipids (Fe2+-induction) were significantly (approx. 20%) decreased after 12 weeks in cardiac and skeletal muscles. The concentration of lipofuscin was unaffected in both muscles of vitamin E-deficient mice. Vitamin E deficiency (5 weeks) decreased the activity of selenium-dependent glutathione peroxidase in skeletal muscle but did not affect the activities of catalase and beta-glucuronidase and the concentrations of protein, reduced glutathione and total sulfhydryl groups. These results show that a short-term vitamin E deficiency affects the peroxidative properties of cardiac and skeletal muscles and may thus expose the muscles to peroxidation injuries.

Studies on cellular autophagocytosis. The relationship of autophagocytosis to protein synthesis and to energy metabolism in rat liver and flounder kidney tubules in vitro.

The purpose of the present study was to elucidate the metabolic requirements of autophagocytosis. Two model systems were used for this purpose: a) glucagon-induced autophagocytosis in the rat liver, and b) the wave of autophagocytosis which occurs when isolated flounder kidney tubules are incubated in vitro. In the rat liver, protein synthesis was inhibited by the administration of cycloheximide (1.5 mg/kg) to rats 2 hours prior to glucagon injection. In flounder kidney tubules, protein synthesis was inhibited at least 90% by adding cycloheximide, actinomycin D, pactamycin and puromycin to the medium. In both systems the inhibition of protein synthesis failed to inhibit the formation of autophagic vacuoles or their subsequent transformation into autolysosomes, as depicted from electron microscopic histochemical preparations. In flounder kidney tubules no differences were found in the levels of p-nitrophenylphosphates, beta-DL-glycerophosphatase, N-acetyl-beta-D-glucosaminidase, arylsulphatase, beta-D-galactosidase or acid proteinase when tubules were incubated up to 5 hours in the presence or absence of protein synthesis inhibitors. When ethionine was administered to rats 2 hours before glucagon injection, a decrease of approximately 75% in the ATP levels was observed. After ethionine administration, glucagon failed to induce the formation of autophagic vacuoles. The incubation of flounder kidney tubules in the presence of cyanide or in a nitrogen atmosphere decreased the ATP levels to less than 10% of controls and blocked autophagy. On the other hand, cyanide had little effect on acid hydrolase levels at 1 hour of incubation. A wide variety of other inhibitors were also shown to block autophagy. These results further support the hypothesis that, in the formation of antophagic vacuoles, preexisting enzyme and membrane pools are utilized. On the other hand, the esotropy-exotropy membrane conformational changes occurring in the formation of autophagic vacuoles seem to be energy dependent and can therefore be blocked by lowering intracellular ATP levels.

Ultrastructural changes in striated muscle after experimental tourniquet ischaemia and short reflow.

The effect of experimental tourniquet ischaemia on the fine structure of a rabbit's hind limb striated muscle was studied. The tourniquet time varied from 1 to 4 h. Samples were obtained from the tibialis anterior muscle 30 min after releasing the tourniquet, the contralateral limb serving as the control. As the first sign of ischaemia, dilatation of the sarcoplasmic reticulum was observed after a tourniquet blockade of 1 h. After 4 h ischaemia myofibrillar components showed advanced degeneration. Ultrastructural alterations were distinct in the mitochondrial morphology. After 2 h, the mitochondria showed moderate but clear condensation. After 3 h many mitochondria showed high amplitude swelling and structural disorganization. Total blockade of the limb circulation up to 4 h effects the energy-producing organelles in the first place, especially sarcoplasmic reticulum, T tubules and mitochondria prior to the alterations in myofilaments. Ischaemia extended up to 3 h induces sublethal damage to the muscle cells.

Morphological and functional differentiation of the surface epithelium of the bursa Fabricii in chicken.

Morphological and functional differentiation of the mucosal surface epithelium of the bursa Fabricii was studied in White Leghorn chicken fetuses and newly hatched chickens. First signs of differentiation towards two types of epithelial cells appeared on the thirteenth day of incubation: The apical cells of the epithelial buds projected towards the lumen, and an increase in the number of Golgi regions was observed in the epithelial cells between the buds. On day 15 the follicle-associated epithelium contained small apically situated vacuoles, and large mucin granules appeared in the interfollicular surface epithelium. Towards the day of hatching both epithelial cell types were arranged to a monolayered or pseudostratified cylindrical epithelium. The follicle-associated epithelium had invaginations and small vacuoles in the apical cytoplasm, whereas the interfollicular surface epithelium had numerous microvilli on its apical surface and large mucin granules in the apical cytoplasm. In functional studies, endocytosis of colloidal carbon was demonstrated in four out of ten 19-day fetuses and in all chickens studied immediately after hatching.

Activity of acid hydrolases in skeletal muscle of untrained, trained and detrained mice of different ages.

The activities of p-nitrophenylphosphatase, beta-glucuronidase and beta-N-acetylglucosaminidase from crude skeletal muscle homogenates of 4 and 7 months old mice were assayed after short-term intensive and long-term moderate training and after terminated training. In the older untrained mice the activity of the hydrolases was higher than in the younger mice. The level increased with training and this increase was far more pronounced in the older animals. Cessation of training for 7 and 21 days decreased this activity in the older animals but it was again increased 42 days later and close to the level observed in the trained mice. In young mice 3 days' terminated training increased the activity of the acid hydrolases above the level of the trained animals but after additional 4 and 11 days' terminated training the activity decreased to slightly below that of the trained mice. The changes were most prominent in the activity of beta-glucuronidase and to a lesser extent in that of beta-N-acetylglucosaminidase while p-nitrophenylphosphatase activity was almost unaffected by training or terminated training. The effects of terminated training can be intepreted as representing altered catabolic processes in the turn-over of tissue components of skeletal muscle.