Neuronal ceroid-lipofuscin storage in a cynomolgus monkey (Macaca fascicularis).

The light and electron microscopical characteristics of non-age-related neuronal ceroid-lipofuscinosis in a young cynomolgus monkey (Macaca fascicularis) are described. The pigment in the neuronal cytoplasm was PAS-positive, sudanophilic, weakly acid-fast, and positive with Schmorl's and aldehydefuchsin stains for lipofuscin. Ultra-structurally, it appeared as membrane-bound, electron-dense aggregates within the cytoplasm of neurones of both brain and spinal cord.

Influence of fenofibrate on cellular and subcellular liver structure in hyperlipidemic patients.

The administration of lipid-lowering drugs to rodents, notably those related to clofibrate, rapidly provokes a hepatic response characterized by hepatomegaly, proliferation of smooth endoplasmic reticulum and proliferation of peroxisomes in hepatocytes. In some studies hepatocellular carcinoma has been found in rats or mice exposed for their entire life-span to high dose levels of various fibrates. In the present study liver biopsy samples were obtained from 38 hyperlipidemic patients, 28 of whom had been receiving fenofibrate for between 2 months and approximately 3 years (mean values: males 1.79, females 1.98 years). The remaining 10 patients had never been treated with a lipid-lowering drug. Examination of the biopsy samples by a variety of optical techniques and by electron microscopy failed to reveal any difference between the groups. Peroxisomes were relatively rare, there being no evidence of the clear proliferation seen in rodent studies. Other microscopic features of interest were some variation of nuclear size, mitochondria containing paracrystalline inclusions, dilated endoplasmic reticulum associated with reduced amounts of rough endoplasmic reticulum, and the presence of lipid droplets in the liver cells. However, these variations from normal were in general not much more apparent in samples from the fenofibrate-treated patients than in the untreated group. Light- and electron-microscopic observations did not suggest liver intoxication or a carcinogenic pattern.

The Clara cell: an electron microscopy examination of the terminal bronchioles of rats and monkeys following inhalation of hexachlorocyclopentadiene.

The effects of inhalation of hexachlorocyclopentadiene (Hex) up to 14 wk on the terminal bronchioles of rats and monkeys was examined by electronic microscopy. Exposed rats elicited a concentration-related increase in the incidence of electron-lucent inclusions in the bronchiolar Clara cells when compared to controls. The inclusions in the high-concentration (0.2 ppm) group were round and more abundant than the rod-shaped inclusions observed in the intermediate (0.05 ppm) and low-concentration (0.01 ppm) exposure group. No ultrastructural changes were observed that could be attributed to the inhalation of Hex vapor in exposed monkeys. The origin and significance of these inclusions is discussed in light of the literature.

Preferential uptake of soluble antigen by respiratory tract epithelium overlying bronchus-associated lymphoid tissue in the rat.

Soluble protein antigen (Horseradish peroxidase - HRP) administered to rats intratracheally is predominantly phagocytosed by alveolar macrophages and Type-II pneumonocytes. A proportion, after localization on the lumenal surface of the bronchiolar epithelium is transported across the epithelium via the apical cytoplasm and the intercellular space to the region of the basement membrane. The rate of transfer is faster in the epithelium closer to areas of BALT than elsewhere and in these areas there is further significant penetration below the basement membrane into the BALT tissue to facilitate the contact of antigen and of lymphoid cells. No evidence of alveolar macrophage re-entry to the lymphatic system after phagocytosis of HRP could be seen.

Chronic intravenous administration of lentinan to the rhesus monkey.

The prolonged effects of overdosage with lentinan in the rhesus monkey are associated with foam cell reactions in lung, liver, kidney, spleen, lymph nodes and bone marrow and with varying degrees of vasculitis and associated reactions. A dose level of 0.5 mg/kg/day was without adverse effect.

The intravenous toxicity of lentinan to the beagle dog.

The i.v administration of lentinan to the Beagle dog induced changes in the cytoplasm of macrophagic cells in the liver, spleen, kidney, lungs, lymph nodes, small intestine. Electron-lucent or filamentous inclusions were demonstrated in the liver, kidney and spleen. A dose level of 0.5 mg/kg/day was without adverse effect.

Distribution and ultrastructural characteristics of Feyrter cells in the rat and hamster airway epithelium.

Feyrter cells were found both singly and in groups at all levels of the respiratory tract studied in both rats and Syrian golden hamsters. Particularly large and prominent groups of Feyrter cells were present at bronchiolar bifurcations and bronchiolar-alveolar junctions. Single Feyrter cells were also found throughout the respiratory tract, but their distribution appeared entirely random. In all cases examined the groups of Feyrter cells were overlaid by intermediate and serous secretory epithelial cells. Occasionally small areas of the Feyrter cells were exposed to the airway lumen. Small canaliculi-like intercellular spaces were present between adjacent Feyrter cells. Single unmyelinated axons which contained neurotubules, mitochondria, and vesicles were occasionally seen in close association with Feyrter cells.

A quantitative ultrastructural comparison of macrophages from rats exposed to smoke derived from conventional tobacco and a tobacco substitute.

Using an image analysing computer a variety of ultrastructural features from micrographs of alveolar macrophages have been quantified. Macrophages from rats exposed to smoke from conventional tobacco cigarettes, for 6 months, revealed statistically significant changes when compared to controls. The macrophages were larger, rounded with fewer pseudopodia and contained increased numbers of inclusions. There were no statistically significant changes in macrophages from rats exposed to smoke from a tobacco substitute.