Deficiency of ascorbic acid in experimental diabetes. Relationship with collagen and polyol pathway abnormalities.

The plasma and tissue concentration of ascorbic acid (AA) is reduced in diabetes. This study was designed to investigate the mechanism and significance of this phenomenon. The low plasma AA concentration of diabetic rats can be normalized by dietary AA supplement (20-40 mg/day), a dosage approximately equal to the maximal synthetic rate of this substance in the rats. Treatment of diabetic rats with this regime prevented the decrease in activity of granulation tissue prolyl hydroxylase (PRLase), an AA-dependent enzyme required for maintaining the normal properties of collagen. The decreased plasma AA concentration and granulation tissue PRLase activity in diabetes can also be normalized by the aldose reductase inhibitor tolrestat. We conclude that in diabetic animals there is a true deficiency of AA that may be responsible for some of the changes of collagen observed in diabetes. Treatment with AA or an aldose reductase inhibitor may prevent some of the diabetic complications with underlying collagen abnormalities.

Local hyperalimentation of open wounds.

After débridement of necrotized and devitalized tissue in deep burns and large traumatic soft tissue defects, the raw surfaces were covered with separate sheets of viscose cellulose sponge (VCS), each moistened by continuous slow infusion of one of the following solutions: (a) 0-9 per cent NaCl; (b) 10 per cent glucose; (c) Rheomacrodex (dextrane hydrolysate in 0-9 per cent NaCl); (d) 7 per cent Levamin (a mixture of essential amino acids and glycin in 5 per cent sorbitol; (e) a combination of two solutions containing amino acids (Le-7402 A) and glucose, electrolytes and vitamins (Le-7402 B). The cellulose sponges were removed or changed 3-7 days later. Macroscopically, histologically and enzyme histochemically, the most active granulation tissue formation was found under the VCS moistened with amino acid solutions, especially when accompanied by glucose and vitamin supplementation. The results strongly suggest that local cellular hyperalimentation of open raw wound surfaces is possible, permitting a new kind of nutritional support in these patients.

Wound healing with adhesive zinc tape. An animal experimental study.

Wound healing was studied in rats given a diet with a subnormal zinc content (10 ppm). It is concluded that wound healing is impaired in the zinc deficient group compared with animals given a zinc-supplemented diet (150 ppm). Local supplementation of zinc with adhesive zinc tape treatment did not return wound healing to normal in the zinc deficient animals. Histological differences were observed between wounds treated with adhesive zinc tape and those treated with a gauze sponge. In particular, a more pronounced giant cell formation was observed in the gauze treated wound. Simultaneously these wounds showed peak activities of the alkaline phosphatases. A reduction of wound contraction was found in tape-treated wounds. A change in macrophage and fibroblast function during local zinc treatment is suggested. Some effects of wound healing on zinc metabolism are discussed.