Subject(s)
Ambulatory Surgical Procedures , Hospital Departments/organization & administration , Surgery Department, Hospital/organization & administration , Competitive Behavior , Humans , Marketing of Health Services , Outpatient Clinics, Hospital/organization & administration , Surgery Department, Hospital/economics , UtahABSTRACT
The effectiveness of prophylactic mastectomy in preventing breast cancer was studied in female albino Sprague-Dawley rats. Group A served as untreated controls. Groups B, C, and D underwent 50%, 75%, and total mastectomies 2 weeks after the administration of 7,12-dimethylbenzanthracene (DMBA). Group E was initially subjected to total mastectomy. Two weeks after surgery, group E received 5 mg of DMBA intravenously. Group F underwent sham procedures. All animals were sacrificed at age 8 months. The mean number of tumors per animal developing in groups A through E was 5.00, 5.17, 4.67, 5.46, and 5.20, respectively. There was 0.21 tumor per animal in group F. The mean time to tumor development in groups A through E was 11.33, 10.05, 9.88, 19.25, and 19.38 weeks, respectively. All results were subjected to an analysis of variance. There was no statistically significant difference in the number of DMBA-induced tumors in groups A through E. Groups D and E had a significant prolonged time to tumor development. The overall risk of the development of breast tumors was not significantly reduced by prophylactic mastectomy. Residual breast tissue after prophylactic mastectomy is at increased risk for the development of breast tumors. The risk of developing breast tumors in this model is not reduced in proportion to the amount of breast tissue removed. (This study suggests that subcutaneous mastectomy in high-risk individuals may not have appropriate prophylaxis against the development of carcinoma of the breast.)
Subject(s)
Mammary Neoplasms, Experimental/prevention & control , Mastectomy , 9,10-Dimethyl-1,2-benzanthracene , Animals , Female , Mammary Neoplasms, Experimental/chemically induced , Rats , Rats, Inbred Strains , Risk , Time FactorsABSTRACT
Avian influenza virus (A/Chicken/Pennsylvania/83; H5N2) was recovered from the yolk, albumen, and shell surface of eggs obtained from naturally infected chicken flocks in Pennsylvania and Virginia. These findings represent the first reported isolation of avian influenza virus from the internal contents of eggs from naturally infected flocks. The need for adequate safeguards to prevent spread of the virus during commercial movement of table and hatching eggs, cracked and "checked" eggs, and egg flats and other materials is emphasized.
Subject(s)
Eggs , Food Microbiology , Influenza A Virus, H5N2 Subtype , Influenza A virus/isolation & purification , Influenza in Birds/transmission , Animals , Chickens , Influenza in Birds/epidemiology , Pennsylvania , VirginiaABSTRACT
Fifty-day-old female, albino Sprague-Dawley rats were induced with DMBA, a potent carcinogen that reliably causes multiple breast tumors. Prophylactic subcutaneous mastectomy was performed 2 weeks after injection. Control animals had no breast tissue removed and developed 5.14 tumors per animal, or 1.3 tumors per quadrant. Animals subjected to 50 percent (unilateral) mastectomy developed 5.4 tumors per animal, with 0.72 tumors per surgical quadrant. Animals that underwent 75 percent (three quadrant) mastectomy developed 4.33 tumors per animal, or 0.48 tumors per surgical quadrant. The incidence of tumors was significantly reduced in the surgical areas. However, the risk of any animal developing a breast neoplasm was not reduced in direct proportion to the percentage of breast tissue removed. We believe that this model may prove valuable in evaluating prophylactic subcutaneous mastectomy.
