The effect of different preparative procedures for electron microscopy on the size and shape of murine oncornaviruses has been studied. With conventional negative staining procedures using neutral sodium phosphotungstate, both murine mammary tumor virus and murine leukemia virus appeared in head-and-tail forms, with a peak head diameter of 122 and 130 nm, respectively. Negative staining with ur...

Alterations in apoptosis and associated mechanisms during mammary tumor progression were investigated in transgenic mice expressing the SV40 large T antigen (T(AG)) driven by the rat prostatic steroid-binding protein C3(1) 5'-flanking region. Apoptosis levels, assessed by in situ end labeling, were low in normal mammary epithelial cells, highest in atypical hyperplasias (preneoplastic lesions),...

Epidemiologic studies have suggested that dietary folate intake is inversely related to breast cancer risk. However, epidemiologic evidence has not been consistent nor has it provided unequivocal support for this purported inverse relationship. This study investigated the effect of dietary folate on N-methyl-N-nitrosourea (MNU)-induced mammary tumorigenesis in rats. Weanling, female Sprague-Daw...

The cyclooxygenase (COX)-2 gene encodes an inducible prostaglandin synthase enzyme that is overexpressed in adenocarcinomas and other tumors. Deletion of the murine Cox-2 gene in Min mice reduced the incidence of intestinal tumors, suggesting that it is required for tumorigenesis. However, it is not known if overexpression of Cox-2 is sufficient to induce tumorigenic transformation. We have der...

AIMS Delineate the feasibility of simultaneous, dual selective "targeted" chemotherapeutic delivery and determine if this molecular strategy can promote higher levels anti-neoplastic cytotoxicity than if only one covalent immunochemotherapeutic is selectively "targeted" for delivery at a single membrane associated receptor over-expressed by chemotherapeutic-resistant mammary adenocarcinoma. M...

Leupeptin is a small peptide microbially derived inhibitor of certain proteolytic enzymes. Using N-alpha-benzoyl-DL-arginine 4-nitroanilide as substrate, we found a novel leupeptin-sensitive proteolytic enzyme in N-methyl-N-nitrosourea(MNU)-induced rat mammary adenocarcinoma. This enzyme was apparently different from urokinase-type plasminogen activator or cathepsin B and was present in mammary...

Mitochondria isolated from normal mammary glands taken from lactating and nonlactating C3H mice were compared with those isolated from mammary adenocarcinomas. Functional mitochondria could be obtained from the normal mammary glands only when milk was not present in the tissue prior to homogenization and when bovine serum albumin was added to the isolation medium. Albumin also protected tumor m...

Curcumin, a phenol in turmeric (Curcuma longa), has been studied for the last decade as a potential anticancer drug. It has been shown to reduce viability of the highly malignant, metastatic rat mammary gland cell line ENU1564 in culture and reduce metastasis of these cells injected into nude mice. The purpose of this study was to identify the mechanisms by which curcumin induces apoptosis in t...