Delayed effects of neonatal exposure to Tween 80 on female reproductive organs in rats.

Neonatal female rats were injected ip (0.1 ml/rat) with Tween 80 in 1, 5 or 10% aqueous solution on days 4-7 after birth. Treatment with Tween 80 accelerated maturation, prolonged the oestrus cycle, and induced persistent vaginal oestrus. The relative weight of the uterus and ovaries was decreased relative to the untreated controls. Squamous cell metaplasia of the epithelial lining of the uterus and cytological changes in the uterus were indicative of chronic oestrogenic stimulation. Ovaries were without corpora lutea, and had degenerative follicles.

Subacute immunotoxicity study of formaldehyde in male rats.

Immune functions were examined in male rats following 28 day oral administration of formaldehyde by gastric tube at dose levels of 0, 20, 40, and 80 mg/kg. Routine parameters examined included hematology, clinical chemistry, and body, thymus, kidney, and liver weights. In addition, cellularity of spleen and lymph nodes, histology of spleen, thymus, lymph nodes, liver kidney, small and large intestines, and histochemistry of spleen and lymph nodes were evaluated. Immune parameters evaluated included serum hemagglutinin antibody response; antibody plaque forming cell response to sheep erythrocytes (lymphocyte-dependent antigen); microbicidal activity of Candida albicans; and phagocytic activity by adhesion of microspheric hydrophilic synthetic particles to leukocyte cell membrane. Body weights were slightly decreased at high dose level (80 mg/kg). The difference was significant when compared to the controls. The lymph node weights were significantly increased in rats receiving formaldehyde. The cellularity of lymphoid organs was not influenced after 28 day exposure to formaldehyde.

[The estrogenic effect of the fungicide Novozír MN 80 on the uterus in neonatal rats]. / Fungicíd Novozír MN 80 a jeho estrogénny úcinok na uterus neonatálnych potkanov.

The estrogenic effect of the ethylenebisdithiocarbamate fungicide Novozír MN 80 (Duslo, Sal') was studied by means of the screening method determining the reproductive risk of chemical substances, recommended by the Environmental Protection Agency. Compared to intact controls, a significant increase in relative uterine weight was recorded in the group of animals which received 1/25 of the maximal tolerable concentration of Novozír MN 80. Compared to negative controls (Tween 80), the relative uterine weight was increased significantly after administration of 1/25 and 1/50 of the maximal tolerable concentration of Novozír MN 80. On histologic examination the cuboidal epithelium of the mucous membrane was found to be changed into columnar epithelium, with uneven distribution of enlarged nuclei in the vacuolized cytoplasm. At 1/25 maximal tolerable concentration thickening of the uterine wall was observed.

Combined chronic toxicity/carcinogenicity study of the fungicide trimorphamide in rats.

Trimorphamide, a new fungicide, was fed over 2 years to groups of 50 male and 50 female rats at dietary levels of 0, 67, 330 and 665 mg/kg. No adverse effects on mortality, haematology, urinalysis, organ weights, incidence and severity of tumors were observed. Isolated observations of abnormalities in blood chemistry suggested the possibility of certain renal damage in the highest dosage group; however, the clinical significance of these findings is dubious. According to the results of the present study, 67 mg/kg in the diet can be considered as the "no observed effect level".

On the mechanism of acute toxicity of phosmet.

Rats were given single oral doses of phosmet (LD50 or 3/4 LD50). Changes of hematological parameters were studied in several time intervals; the main interest was paid to disturbances in blood clotting. Both light and electron microscopy were used to evaluate histopathological changes in selected organs (liver, lungs, spleen, stomach). Marked changes could be observed in all blood clotting parameters studied, other findings were not standard. The pathological picture was dominated by endothelial damage to the blood vessels and findings of thrombocytic clots in microcirculation of all organs examined. Together with hemocoagulation changes, they could be considered as reflecting the compensated stage of diffuse intravascular coagulopathy. In addition, damaged alveolar endothelium and interstitial edema could be observed in the lungs together with hepatic steatosis, damaged proximal renal tubuli, release of cellular elements from the splenic pulp and decomposition of megakaryocytes as well as serious exfoliation of the superficial layers of the gastric mucosa. The pathohistological alterations coincided with changes in organ weights.