No abstract

HE THREAT OF SMALLPOX BIOterrorism has prompted reconsideration of the need for smallpox vaccination. 1-3 Serious adverse events associated with firstgeneration vaccines such as the New York City Board of Health (Dryvax; Wyeth, Madison, New Jersey), Lister, and Ikeda strains 4-8 have raised obstacles to vaccination campaigns in the United States. 7-9 Second-generation vaccines such as ACAM2000 (Acambis, Cambridge, Massachusetts) that use a first-generation seed virus but are grown in tissue culture are also usually accompanied by a high frequency of adverse events. 10 Developing a vaccine that is safer than first-generation vaccines yet highly immunogenic is crucial to constructing a prevention plan in the event of bioterrorist attack. LC16m8 is a live, attenuated, tissuecultured third-generation vaccine comprising attenuated vaccinia virus strains as well as subunit vaccines made from viral proteins or DNA. 11 It is a desirable candidate for routine vaccination because of its low reactogenicity and reasonable safety profile. 12 Vaccination can be conveniently accomplished with a single intraepidermal scarification alone, which usually results in a visible major skin reaction ("take") similar to those resulting from first-and second-generation vaccines. 13 LC16m8 was derived from the Lister strain used for the Intensified Smallpox Eradication Programme of the World Health Organization 4 by temperature sensitivity and pock size See also Patient Page.

Some sulfated polysaccharides, such as d-CGN, APS, and DSS, have carcinogenicity to the rat colorectum. These materials first induced colitis, secondly squamous metaplasia, and finally tumors at the colorectum. Initially, colitis was located in the columnar epithelium of the rectum and extended proximally thereafter. Squamous metaplasia persisted in almost all experimental rats and progressed irreversibly. The tumors were adenoma, adenocarcinoma, squamous cell papilloma, and squamous cell carcinoma. Macrophages containing these materials were observed in the lamina propria mucosa and submucosa of the colorectum. There were differences in the molecular weight of the substances and their tumor incidences. However, with regard to their carcinogenicity, these sulfated polysaccharides were inferred to be similar to each other in their target organs and process of tumor development. Consequently, these sulfated polysaccharides may be one entity of carcinogenic sulfates.

These results suggested that 70% to 80% of SCa developed via a de novo carcinoma theory and showed the depression form in the initial histologic stage and thereafter in the flat-protrusion form, while 20% to 30% of SCa arose from the preexisting flat adenoma via the adenoma-carcinoma sequence theory. The results also suggested that p53 was related to the enlargement and deeper invasion of SCa, regardless of the sequence of development of colorectal cancer.