Receptors for advance glycation end-products (AGE) - expression by endothelial cells in non-diabetic uraemic patients.

BACKGROUND: Cellular actions of advanced glycation end-products (AGE) are mediated by a receptor for AGE (RAGE), a novel integral membrane protein. Immunohistochemical studies show only low-level RAGE antigen expression in endothelial cells. Design. It was the purposes of the study to compare expression of RAGE antigen by endothelial cells in non-diabetic uraemic patients (n=8) with non-uraemic controls (n=11). Samples of arterial tissue were obtained at the time of renal transplantation (in uraemic patients) and abdominal surgery (in controls). RAGE antigen was visualized using guinea-pig anti-RAGE IgG and PAP technique. RESULTS: Marked staining for RAGE was noted in endothelial cells, both arterial endothelium and endothelium of vasa vasorum of normoglycaemic uraemic patients, but was not demonstrable in endothelial cells of large arteries and only faintly expressed in vasa vasorum of non-uraemic individuals. CONCLUSION: Normal endothelial cells do not constitually express RAGE antigen; in contrast it is expressed by arterial and capillary endothelial cells of uraemic patients. The observation is of note in view of the putative role of AGE of causing atherosclerotic and non-atherosclerotic vascular lesions.

Improvement of oral mucosa with mucin containing artificial saliva in geriatric patients.

In elderly individuals the saliva production is often decreased, leading to dry mucosal membranes and predisposition to local infections, as well as other oral problems. Eighty-five hospitalized geriatric patients, with a multitude of disabling diseases, participated in a double blind placebo-controlled study when mucin-containing artificial saliva and a placebo liquid was given. In the patients treated with the artificial saliva a considerable improvement in the condition of oral mucosa was seen. Also, in one quarter of the patients treated with the placebo liquid, the oral candida infection disappeared, possibly due to improved oral hygiene. It is reasonable to assume that general well-being increases when the condition of the oral mucosa improves. If factors causing dry mouth cannot be removed, i.e. due to diseases or ageing factors, treatment with artificial saliva could be of benefit, but the importance of good oral hygiene must not be overlooked.

The condition of the oral mucosa in institutionalized elderly patients before and after using a mucin-containing saliva substitute.

The purpose of this investigation was to evaluate whether the condition of the oral mucous membrane and the mouth comfort of the elderly could improve using a mucin-containing saliva substitute. In total, 52 patients were examined before and after a 60-day treatment period, with mucin-containing saliva substitute given three times a day before meals. The patients were examined with regard to weight, oral mucosa condition, the duration of meals, eating and swallowing. Before the treatment period the prevalence of stomatitis was 90.4% and oral candidosis was 80.8% compared to 15.4% and 5.8% respectively after the treatment period. The pH increased significantly. Artificial mucin-containing saliva substitute seems to be an adequate treatment of stomatitis and oral candidosis in elderly patients.

Diurnal rhythms in rat plasma amino acids.

To obtain detailed data on the diurnal rhythm in rat plasma amino acids, groups of rats were killed every two hours during 24 hours and the amino acids in plasma were measured. By using such a short interval between the blood samples, it was possible to reveal differences in rhythmicity between the various amino acids, more detailed than those previously described. Furthermore, it was found that those large neutral amino acids (LNAA) which compete with each other for the carrier mediated transport from plasma into the brain demonstrated different rhythms, whereby also the relation between these competing amino acids varied during the day. This finding might have implications for the transport of the various LNAAs into the brain, and secondarily also for the synthesis of the monoaminergic neurotransmitters in the neurons, for which the LNAAs tyrosine and tryptophan serve as precursors.

Rat brain concentration of administered amino acids: dependence on time of day for administration.

Several large neutral amino acids (LNAA) (e.g. L-DOPA and L-tryptophan) are used as therapeutic agents. To reach the brain they have to compete with the naturally occurring large neutral amino acids for the saturable, carrier mediated transport into the brain. Since the concentration of LNAA in plasma demonstrates a diurnal rhythm, this competition could be expected to vary accordingly. To investigate if this variation could influence the brain concentration of a certain administered amino acid we injected three groups of rats with L-DOPA, L-tryptophan or saline in the afternoon when the rat plasma concentration of LNAA is at its lowest. Three other groups of rats received the same treatments at 3 a.m., when the concentration of LNAA is reported to be at a maximal level. The brain concentrations of the administered amino acids were significantly higher and LNAA in plasma lower in the groups injected in the afternoon compared with those injected during the night. These findings support the hypothesis that the time of the day when an amino acid is administered is of importance to the concentration of the administered amino acid in the brain.