Biological behaviour and morphological characteristics of a transplantable tumour derived from a uterine smooth muscle tumour in the F344 rat.

A subcutaneously transplantable tumour (SMT-Y) was established from a smooth muscle tumour arising from the uterus of a female F344 rat. SMT-Y was serially passaged by subcutaneous implantation into syngeneic female rats up to the 15th generation, but transplantation failed in males. The rat with the primary uterine tumour also had mononuclear cell leukaemia (MCL), and MCL cells grew concurrently in implanted rats. At passage five, MCL cells were eliminated from transplants by implanting the central part of an SMT-Y nodule, consisting only of neoplastic smooth muscle cells. SMT-Y at passages six to 15 was examined biologically and morphologically. The primary tumour and SMT-Y tumours consisted mainly of interlacing fascicles of elongated and fusiform neoplastic smooth muscle cells with abundant cytoplasm. Occasional cells showed nuclear atypia. Mitosis counts per 10 high-power microscopic fields in the primary tumour and SMT-Y ranged from 11 to 36. Neoplastic cells reacted positively for desmin, muscle actin and myosin, but not for myoglobin. Electron microscopy revealed cytoplasmic myofilaments with oval dense bodies. These findings suggested a smooth muscle origin of SMT-Y and it was regarded as a leiomyosarcoma by the criteria for human uterine smooth muscle tumours. Despite the malignant histological features, SMT-Y grew slowly into a large nodule, with an average diameter of 5 cm and average weight of 81 g, 24 weeks after transplantation. Neither invasive tumour growth nor metastases were observed in SMT-Y-bearing rats.

Comparison of immunity induced with a Mycoplasma gallisepticum bacterin between high- and low-responder lines of chickens.

Chickens of the high-responder line GSP and low-responder line BM-C, which had been known to have different antibody responses to Mycoplasma gallisepticum (MG) antigen, were immunized by intramuscular injection and by subsequent intratracheal instillation of MG bacterin. They were then challenged with the pathogenic strain SAS of MG. The preventive effects of local antibodies detectable in the trachea, saliva, and lacrima were compared between the two lines of chickens. The local antibody responses, as determined by an enzyme-linked immunosorbent assay, were higher in line GSP than in line BM-C before and after challenge. Following challenge, chickens of both lines were protected from colonization by MG and the development of respiratory lesions. The degree of protection in line GSP was higher than that of line BM-C. The results suggest that local antibodies may play an important role in the host defense mechanism to respiratory MG infection.

Genesis of pulmonary foam cells in rats with diet-induced hyper beta-lipoproteinaemia.

Hyper beta-lipoproteinaemia in rats was produced by feeding a standard diet to which was added excess cholesterol and cholic acid, with or without olive oil, for 4, 8, and 12 weeks. The beta-lipoprotein percentage in serum lipoprotein electrophoresis and lipid contents in very low density lipoprotein and low density lipoprotein fractions in these rats were significantly higher than in the control rats fed the standard diet only. The percentage of foamy monocytes (FMs) to the total number of blood monocytes (BMs) from mononuclear leucocyte fractions and percentage of pulmonary foam cells (PFCs) to the number of alveolar macrophages (AMs) from bronchopulmonary lavage fluids in the rats increased with the extension of the feeding period and were significantly higher than those in the controls. An increase in the percentage of PFCs was closely correlated with that of FMs in the rats. FMs and PFCs had cytoplasmic fine vacuoles proved to be neutral lipid and cholesterol. Histologically, PFCs made an appearance in the lungs of all the rats as early as 4 weeks after the start of feeding. The degree of the PFCs' development increased as the feeding period lengthened. When latex particles were injected intravenously into rats at feeding week 4, the percentage of latex-ingested AMs to the number of AMs in the rats was significantly higher than that of the controls at 4 and 8 days post-injection. The percentage of latex-ingested PFCs to the number of latex-ingested AMs increased with the lapse of a day after injection and was significantly higher than that of the controls at 2, 4, and 8 days post-injection. The present findings suggest that the foamy transformation of BMs and their migration into the pulmonary alveoli may be a potential mechanism of the PFCs' development in rats with hyper beta-lipoproteinaemia.

Background pathology in BDF1 mice allowed to live out their life-span.

Fifty male and 50 female BDF1 mice were observed allowing them to live out their life-span. Mortality up to 104 weeks of age was higher in males (42%) than in females (34%), and the 50% survival age was 112 weeks for males and 118 weeks for females. Body weight reached the peak at 82 weeks of age in males and 92 weeks of age in females, showing the mean body weight of 54.3 g for males and 48.0 g for females. The incidence of calculi and proteinaceous casts in the kidneys, that were not associated with exposure to chloroform, cell-alteration in the adrenal cortex, and islet cell hyperplasia in the pancreas was significantly higher in males than in females. On the other hand, hyaline droplet degeneration of the renal tubular epithelium, spindle cell proliferation in the adrenal cortex and milk-retention in the mammary glands occurred at a significantly higher incidence in females than in males. Cerebral mineralization in both sexes, atrophy and calcification of the testes and enlargement of the seminal vesicles of males, as well as cyst-formations in the ovary and endometrium of females developed at a very high incidence. Frequent neoplasms in males were hepatocellular adenomas and carcinomas, blood vessel tumours, pulmonary adenomas and carcinomas, and malignant lymphomas. In females, malignant lymphomas were the most common neoplasm, followed by blood vessel tumours, chromophobe pituitary adenomas and hepatocellular adenomas. Hepatocellular carcinomas developed only in males, whereas the histiocytic and lymphocytic types of malignant lymphomas and chromophobe cell adenomas arose solely or at a significantly higher incidence in females than in males.