Mechanical and humoral factors in wound healing

As wound contraction can be prevented by full-thickness skin graft and enhanced by licking and since saliva contains growth-promoting macromolecules, we have studied the mechanical and humoral aspects of wound healing.

Standardized burn and freeze-produced wounds were produced in rats. Contraction did not occur in wounds caused by freezing (n = 30), while burn wounds (n = 30) contracted to less than one-third of the original size in 3 weeks. If the centres of the freeze-produced wounds (n = 12) were excised, contraction would then occur and proceed at the same rate as open wounds (n = 12). The collagen contents of the burn wounds (n = 24) showed a greater initial loss followed by rapid replacement, while that of the freeze-produced wounds (n = 24) demonstrated a slower removal and more gradual replacement.

Submandibular sialadenectomized mice (n = 34) and sham controls (n = 34) had excision of a standard sized patch of sacral skin. Through a separate abdominal incision polyvinyl sponges of known weight were introduced subcutaneously into all the animals. Mice without the submandibular salivary glands showed a slower rate of wound contraction than the sham controls (P<0.001). However, this delay in wound contraction was abolished if sialadenectomized mice were caged with mice having intact salivary glands. Collagen synthesis as determined by the hydroxyproline concentrations in the polyvinyl sponges were the same in both groups of animals irrespective of cage environment. Further standard sacral wounds in submandibular sialadenectomized mice (n = 120) were treated with different salivary components. Only high molecular weight nerve growth factor was able to accelerate wound contraction in these sialadenectomized animals to control values.

In conclusion, the degree of wound contraction following injury is dependent on the integrity of the matrix, while the initiation of contraction is likely to be chemically induced.

Pseudotumor at the confluence of the hepatic ducts as a pitfall of percutaneous transhepatic cholangiography

Four patients with jaundice who had misleading diagnoses as a result of percutaneous transhepatic cholangiography are reported upon. Three of these patients actually had calculous disease and the fourth had pancreatic disease. The levels of obstruction were also roentgenographically inaccurate in three of the four patients. The primary cause of the error appears to be poor mixing of the contrast material with viscid stagnant bile, resulting in blurred definition and failure of the contrast material to traverse the common bile duct.

Nerve growth factor: acceleration of the rate of wound healing in mice

Earlier studies have shown that removal of the submandibular glands of mice retards the rate of contraction of experimentally induced wounds and that communal licking of wounds accelerates contraction in intact animals [Hutson, J. M., Niall, M., Evans, D. & Fowler, R. (1979) Nature (London) 279, 793-795]. In the light of the observation that nerve growth factor (NGF) is secreted in high concentrations in mouse saliva, we have studied the effect of topically applied high molecular weight nerve growth factor (HMW-NGF) upon the rate of wound contraction in sialoadenectomized animals. Results show that HMW-NGF significantly accelerates the rate of wound contraction and that this phenomenon is probably dependent upon the enzymic activity of the protein. Neither diisopropyl fluorophosphate-inactivated NGF nor 2.5S NGF [isolated according to Bocchini, V. & Angeletti, P. U. (1969) Proc. Natl. Acad. Sci. USA 64, 787-794] displays this biological activity. Thus, it may be that one of the physiological roles of NGF in saliva is to promote wound healing by the licking process.

Differences in healing of skin wounds caused by burn and freeze injuries

Circular, full-thickness dermal burn- and freeze-produced wounds were produced in rats to compare the difference in healing between the two types of thermal injuries. Contraction did not occur in wounds (n = 30) caused by freezing, while burn wounds (n = 30) contracted to less than one-third of original size by 21 days after injury. If the centers of the freeze-produced wounds (n = 12) were excised, contraction would then occur and proceed at the same rate as an open wound. Histologically, the degree of initial tissue destruction by the two types of injuries was similar. The burn wound contained only half the amount of collagen found in the freeze-produced wound. There was a greater and more rapid replacement of collagen in the burn wounds. With both injuries, the highest concentration of collagen was found on the fifteenth day and returned to normal by the twenty-eighth day. The burn wound contained three times the amount of collagen in normal skin, while the freeze-produced wound contained only 1 3/4 times the amount in normal skin. Contraction does not seem to occur in the healing of the freeze-injured skin because the slow removal and replacement of the residual matrix prevents contraction.

Spontaneous liver rupture in polyarteritis nodosa

An unusual case of spontaneous rupture of the liver associated with polyarteritis nodosa is reported.

Experimental smooth muscle antibodies

Attempts were made to induce smooth muscle antibody (SMA) in rats by various procedures causing cell necrosis. Ligation of a liver lobe and cryosurgical damage to a liver lobe both resulted in subsequent appearance of SMA, provided the damage tissue was not removed. Transfer of the damaged liver tissue to the peritoneal cavity of a normal rat did not result in SMA production in the recipient. The SMA produced showed anti-actin and anti-heavy meromyosin specificity. Damage induced by hepatotoxic agents failed to give rise to SMA.

A technique for re-exploration of the saphenofemoral junction for recurrent varicose veins

A safe and simple method is described for re-exploration of the saphenofemoral junction in patients with recurrent varicose veins following incomplete 'Trendelenburg operation'.