The essential oil from clove Syzygium aromaticum (L.) Merr. & Perry exhibited significant antimicrobial activity against a collection of 25 different genera of test bacteria and 20 different isolates of Listeria monocytogenes. The oil was also tested against three fungal strains: a plant pathogen, a spoilage type and a mycotoxigenic strain. This resulted in high levels of growth inhibition at both concentrations of 1 and 10 μl ml−1 growth medium. The essential oil was fed to mice in order to assess the antioxidant capacity, with particular reference to the protection of polyunsaturated fatty acids, in the liver and retina during ageing.

Immunoelectron microscopic investigations were carried out to study the substance P, vasoactive intestinal polypeptide (VIP) and somatostatin immunoreactive nerve elements in the wall of the small intestine. In young and old animals a large number of immunoreactive nerve fibers were found in all layers of the small intestine. They were observed closely to the epithelial cells, to the blood vessel basement membrane and to the smooth muscle cells and in some cases they were observed in a synapse with other unlabelled nerve fibers. On the other hand, in the senile animals very few immunoreactive nerve fibers were observed, calculated for a 100 μm² tissue area. In the senile animals the overall number of nerve fibers was decreased in comparison to the young and old animals and most of them were in degeneration. This change could be the cause of the changes in the senescence-related epithelial transport processes and furthermore, of the modifications of the overall intestinal motility of the gastrointestinal tract, resulting in the age-dependent transit rates.

No abstract

In old CBA/Ca mice the effect of cigarette smoke was compared with that of 2-mercaptoethanol (2-ME) treatment. It could be stated that spontaneous death was more frequent in animals kept in cigarette smoke than in the control animals. Prevalence of hepatocellular carcinoma was higher in animals kept in cigarette smoke than in the controls. After 2-ME treatment the occurrence of hepatocellular carcinoma was significantly lower and animals without disorders were more frequent than in smokers. Body weights were lower in animals kept in cigarette smoke and differences in organ indices could be observed, too. Immunological changes were also demonstrated: in mice kept in cigarette smoke the reactivity against a foreign antigen such as sheep erythrocytes (SRBC) was lower, while after 2-ME treatment it was higher than in their controls using direct plaque formation technique. The ratio of normal reactivity (against SRBC) and autoreactivity (against mouse erythrocytes) showed a decrease in smoker animals, and an increase in the 2-ME-treated ones. The experiments showed a deleterious effect of cigarette smoke and a beneficial effect of 2-ME on age-related alterations.

There is a diminution of D-glucose absorption in the aged rat which is partly due to the decrease of the length of the villi.