Formaldehyde was administered for 104 weeks in drinking water supplied ad libitum at concentrations of 1500, 1000, 500, 100, 50, 10, or 0 mg/L to groups of 50 male and 50 female Sprague-Dawley rats beginning at seven weeks of age. Control animals (100 males and 100 females) received tap water only. Acetaldehyde was administered to 50 male and 50 female Sprague-Dawley rats beginning at six weeks of age at concentrations of 2,500, 1,500, 500, 250, 50, or 0 mg/L. Animals were kept under observation until spontaneous death. Formaldehyde and acetaldehyde were found to produce an increase in total malignant tumors in the treated groups and showed specific carcinogenic effects on various organs and tissues.

Methyl alcohol was administered in drinking water supplied ad libitum at doses of 20,000, 5,000, 500, or 0 ppm to groups of male and female Sprague-Dawley rats 8 weeks old at the start of the experiment. Animals were kept under observation until spontaneous death. Ethyl alcohol was administered by ingestion in drinking water at a concentration of 10% or 0% supplied ad libitum to groups of male and female Sprague-Dawley rats; breeders and offspring were included in the experiment. Treatment started at 39 weeks of age (breeders), 7 days before mating, or from embryo life (offspring) and lasted until their spontaneous death. Under tested experimental conditions, methyl alcohol and ethyl alcohol were demonstrated to be carcinogenic for various organs and tissues. They must also be considered multipotential carcinogenic agents. In addition to causing other tumors, ethyl alcohol induced malignant tumors of the oral cavity, tongue, and lips. These sites have been shown to be target organs in man by epidemiologic studies.

Aspartame (APM) is one of the most widely used artificial sweeteners in the world. Its ever-growing use in more than 6000 products, such as soft drinks, chewing gum, candy, desserts, etc., has been accompanied by rising consumer concerns regarding its safety, in particular its potential long-term carcinogenic effects. In light of the inadequacy of the carcinogenicity bioassays performed in the 1970s and 1980s, a long-term mega-experiment on APM was undertaken at the Cesare Maltoni Cancer Research Center of the European Ramazzini Foundation on groups of male and female Sprague-Dawley rats (100-150/sex/group), 8 weeks old at the start of the experiment. APM was administered in feed at concentrations of 100,000, 50,000, 10,000, 2,000, 400, 80, or 0 ppm. Treatment lasted until spontaneous death of the animals. The results of the study demonstrate that APM causes: (a) an increased incidence of malignant tumor-bearing animals, with a positive significant trend in both sexes, and in particular in females treated at 50,000 ppm (P < or = 0.01) when compared to controls; (b) an increase in lymphomas-leukemias, with a positive significant trend in both sexes, and in particular in females treated at doses of 100,000 (P < or = 0.01), 50,000 (P < or = 0.01), 10,000 (P < or = 0.05), 2000 (P < or = 0.05), and 400 ppm (P < or = 0.01); (c) a statistically significant increased incidence, with a positive significant trend, of transitional cell carcinomas of the renal pelvis and ureter in females and particularly in those treated at 100,000 ppm (P < or = 0.05); and (d) an increased incidence of malignant schwannomas of the peripheral nerves, with a positive trend in males (P < or = 0.05). The results of this mega-experiment indicate that APM, in the tested experimental conditions, is a multipotential carcinogenic agent.

Aspartame (APM) is an artificial sweetener used since the 1980s, now present in >6,000 products, including over 500 pharmaceuticals. Since its discovery in 1965, and its first approval by the US Food and Drugs Administration (FDA) in 1981, the safety of APM, and in particular its carcinogenicity potential, has been controversial. The present commentary reviews the adequacy of the design and conduct of carcinogenicity bioassays on rodents submitted by G.D. Searle, in the 1970s, to the FDA for market approval. We also review how experimental and epidemiological data on the carcinogenic risks of APM, that became available in 2005 motivated the European Commission (EC) to call the European Food and Safety Authority (EFSA) for urgent re-examination of the available scientific documentation (including the Searle studies). The EC has further requested that, if the results of the evaluation should suggest carcinogenicity, major changes must be made to the current APM specific regulations. Taken together, the studies performed by G.D. Searle in the 1970s and other chronic bioassays do not provide adequate scientific support for APM safety. In contrast, recent results of life-span carcinogenicity bioassays on rats and mice published in peer-reviewed journals, and a prospective epidemiological study, provide consistent evidence of APM's carcinogenic potential. On the basis of the evidence of the potential carcinogenic effects of APM herein reported, a re-evaluation of the current position of international regulatory agencies must be considered an urgent matter of public health.

We investigated the functionalization of polymers with pedant ester groups by enzymatic transesterification. By detailed NMR analysis we have shown that while the monomer can be enzymatically modified, surprisingly no reaction was obtained upon polymerization. The results suggest that the formation of the enzyme-activated ester is hindered in the case of the polymer. This was overcome by the introduction of a spacer, thereby forming a polymer with two different pedant ester groups. NMR analysis confirmed high regioselectivity in the transesterification, namely the exclusive reaction on the distant ester group. We moreover combined two modes of selectivity, that is, regio- and stereoselectivity, by the kinetic resolution of a secondary alcohol in the functionalization of the polymer. This concept holds promises as it allows the design of materials with engineered-in highly selective reactivity toward enzymatic reactions.