Manifestation of hyperplastic alveolar nodules and mammary tumors in "viable yellow" and non-yellow mice.

The time course of appearance of hyperplastic alveolar nodule(s) (HAN) and mammary tumor(s) (MT) was determined in untreated virgin "viable yellow" (Avy/A) and non-yellow (A/a) (C3H/HeNIcrWf X VY/Wf)F1 female mice. The first HAN was detected in a yellow female at age 16 weeks, the first period in which mice were killed. HAN were not found in the non-yellow mice until they were 19 weeks old. The incidence of HAN increased to 92% among yellow females and to 75% among non-yellow females by 36 weeks of age. MT were first observed at age 22 weeks in yellow mice and at 28 weeks in non-yellow mice. The incidence of MT at 36 weeks was 75% among yellow mice and 22% among non-yellow mice. Type B adenocarcinoma was the predominant class of MT found in the yellow mice. The time courses of appearance and incidence of HAN and MT in the non-yellow F1 mice were similar to those observed in inbred C3H female mice. MT first appeared in each population when the incidence of HAN bearers had reached 40--45% regardless of age, body weight, or number of HAN per HAN bearer. Apparently, the phenotypic effects of the Avy gene primarily stimulated the multiplication of nodule-transformed cells to form HAN and thus indirectly enhanced MT formation.

Incidence of pulmonary metastases for various neoplasms in BALB/cStCrlfC3H/Nctr female fed N-2-fluorenylacetamide.

Incidence of pulmonary metastases for a variety of neoplasms was studied in many inbred BALB/cStCrlfC3H/Nctr female mice fed 2-fluorenylacetamide. Bladder carcinomas and hepatocellular carcinomas appeared to be the only neoplasms that were dose related. Hepatocellular carcinomas metastasized to the lungs at an incidence of 4.8%, and bladder carcinomas metastasized at an incidence of 0.28%. Osteogenic sarcomas metastasized to the lungs at an incidence of 46.2%; renal adenocarcinomas, at 20%; fibrosarcomas, at 16.7%; mammary adenocarcinomas, at 9.8%; and myoepitheliomas, at 10.5%. Other malignant neoplasms, including leiomyosarcomas, granulosa cells tumors, adrenocortical carcinomas, angiosarcomas, squamous cell carcinomas, and harderian gland tumors, metastasized at an incidence of less than 5%.

Analysis of Salmonella serotypes from selected carcasses and raw ground products sampled prior to implementation of the Pathogen Reduction; Hazard Analysis and Critical Control Point Final Rule in the US.

In July 1996, the US Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS), published the Pathogen Reduction; Hazard Analysis and Critical Control Point (HACCP) Systems final rule to improve food safety of meat and poultry products. The final rule established, among other requirements, pathogen reduction performance standards for Salmonella for food animal carcasses and raw ground products. The final rule is to be fully implemented in three stages in successively smaller federally inspected meat and poultry slaughter and processing establishments. Implementation began in January 1998 and was completed in January 2000. Samples of carcasses of four species of food animals (cattle, swine, chickens, turkeys), and raw ground product from each of these species, were collected by FSIS from establishments prior to implementation of the final rule and cultured for Salmonella. This paper reports Salmonella serotype results of samples collected from June 1997 through August 1998. These results represent a baseline for future comparisons.

Hematologic and clinical chemistry findings in control BALB/c and C57BL/6 mice.

The normal ranges for a variety of hematologic and clinical chemistry findings in 1,540 control BALB/c and C57BL/6 mice of various ages was determined. The total leukocyte count for both strains was highest at 1-3 months of age, and it usually decreased slightly until the mice were 18 months old. Hemoglobin values decreased with age. In both strains, the values for phosphorous, calcium, alkaline phosphatase, and urea nitrogen decreased after 3 months of age and then increased after 12 months of age. Differences between sexes were present for one or both of the strains for hemoglobin, phosphorus, glucose, cholesterol, aspartate aminotransferase, total protein, albumin, and alkaline phosphatase.