Ultrastructure of free nerve endings in respiratory and squamous epithelium on the rat nasal septum

The distribution of nerve fibres in the mucosa of the nasal septum of the rat was investigated by means of transmission electron microscopy on transverse and tangential ultrathin sections. Near the basement membrane of respiratory and squamous epithelium, a rather dense network of unmyelinated nerve fibres occurs. Some fibres in the respiratory...

The role of nasopharyngeal lymphoid tissue

Characterization of adenocarcinomas of the dorsolateral prostate induced in Wistar rats by N-methyl-N-nitrosourea, 7,12-Dimethylbenz(a)anthracene, and 3,2'-Dimethyl-4-aminobiphenyl, following sequential treatment with cyproterone acetate and testosterone propionate

Carcinomas of the rat prostate induced by a single injection of N-methyl-N-nitrosourea, 7,12-dimethylbenz(a)anthracene, and 3,2'-dimethyl-4-aminobiphenyl, after sequential treatment with cyproterone acetate and testosterone propionate, were evaluated as potential animal model for prostatic cancer. All ten carcinomas examined were located in the...

Cytotoxic and adaptive effects in rat nasal epithelium after 3-day and 13-week exposure to low concentrations of formaldehyde vapour

To study in detail possible effects of low concentrations of formaldehyde on the nasal epithelium, Wistar rats were exposed to 0, 0.3, 1 and 3 ppm formaldehyde vapour for 6 h/day, 5 days/week during 3 days or 13 weeks, using in vivo [3H]thymidine labeling for cell proliferation studies, and light and electron microscopy for detecting...

Pulmonary response of hamsters to fibrous glass. - Clearance and morphology after a single intratracheal instillation

In a one-year serial sacrifice study 10 mg glass fibres (length, 95% ?? 20 ??m, 89% ?? 12 ??m, 58% ?? 5 ??m and 25% ?? 2 ??m; diameter, 88% ?? 1.0 ??m, 60% ?? 0.5 ??m and 31% ??0.25 ??m) suspended in 0.2 ml saline solution were administered to Syrian golden hamsters by a single intratracheal instillation to determine the clearance of the glass...

Influence of retinoids on the mutagenicity of cigarette-smoke condensate in Salmonella typhimurium TA98

The effects of 3 different retinoids (all-trans-retinol, all-trans-retinoic acid, and all-trans-retinyl acetate) on the mutagenic activity of cigarette-smoke condensate were investigated in Salmonella typhimurium TA98. Neither an enhancing nor an inhibitory effect of the retinoids on the mutagenicity of cigarette-smoke condensate was observed....

Pulmonary response of hamsters to fibrous glass: Chronic effects of repeated intratracheal instillation with or without benzo[a]pyrene

Syrian golden hamsters were given intratracheal instillations of glass fibres with or without benzo[a]pyrene suspended in saline, once a fortnight for 52 weeks. The experiment was terminated at week 85. 'Silicotic granulomas' consisting of tightly packed, iron-positive macrophages filled with glass fibres and surrounded by a layer of alveolar...

Restoration of the hamster tracheal wall following injury by electrocoagulation

The trachea of Syrian golden hamsters was injured by electrocoagulation. The lesions induced as well as the repair process were studied by light and scanning electron microscopy. The changes observed were considered to create the proper conditions for studying the significance of severe focal damage to the respiratory tract for the formation of...

Electrocoagulation as a method to induce local lesions in the tracheal wall of Syrian hamsters

Tissue damage and nutritional factors in experimental respiratory tract (co-)carcinogenesis

Cofactors involved in respiratory tract carcinogenesis were studied in Syrian golden hamster or in rats using benzo(a)pyrene as the carcinogenic agent. These factors included severe tissue tissue damage induced by electro-coagulation, glass fibers administered by intratracheal instillation, acetaldehyde as irritant vapor, food restriction, and...

Nature and histogenesis of sulfite-induced gastric lesions in rats

A variety of gastric lesions can be induced in rats by sodium metabisulfite, including the formation of scattered hyperplastic glands in the fundic mucosa which are exclusively lined by large uniform cells, laden with acidophilic granules. Light and electron microscopy, as enzyme histochemistry, showed that the cells lining these glands are...

Lifespan oral toxicity study of vinyl chloride in rats

A lifespan oral toxicity of vinyl chloride monomer (VCM) was carried out in Wistar rats, using five groups each of 60-80 males and 60-80 females. VCM was administered by incorporating polyvinyl chloride (PVC) powder with a high VCM content into the diet or by gastric intubation of a 10% VCM solution in soya-bean oil. The VCM doses (actual...

Ultrastructure of hepatic angiosarcoma in rats induced by vinyl chloride

The hepatic angiosarcoma studied was from a male Wistar rat having been exposed to vinyl chloride monomer (VCM) by the oral route for 120 weeks. Widened sinusoids lined by large electron-lucent, spindle-shaped tumor cells and membrane-bound nuclear-free structures were seen in the transitional zone between the tumor mass and the adjacent liver...

Ultrastructural changes in the kidneys of rabbits treated with lead acetate

Electron microscopical studies were carried out on the kidneys of rabbits given s.c. injections of 0 (control), 0.25 or 0.50 mg lead acetate/kg b.w. 3 times a week during 14 weeks. At the end of the experimental period the animals had lead blood levels of 60, 500 and 600 ??g/1 whole blood respectively. Treatment-related renal changes were found...

Microscopisch onderzoek van bouwmaterialen: microstructuur van gasbeton

This article comprises the preliminary results obtained through electron microscopic and scanning electron microscopic investigation of cellular concrete. The electron micrographs represent pictures of thin sections through the material between the grains of sand. Pores from 5 - 50 nm could be recognized. Scanning electron micrographs show the...

Industriële elektronenmicroscopie

Application of the electron microscope for investigation of industrial products and processes is shortly discussed. Attention is paid to investigation of small particles and structure problems in its diversification. Electron micrographs support the described possibilities.

A new type of bacterial cell wall structure revealed by replica technique

The exterior of the cell wall of a photo-organotrophic, gram-negative, motile bacterium was investigated by means of the pre-shadowed replica technique. A detailed description of the technique is given. Replicas of intact cells show bacterial cell walls with a striated structure. The surface is composed of areas of different size and shape, each...