Prevention and treatment of amputation neuroma by an atelocollagen tube in rat sciatic nerves.

To evaluate the potential of the atelocollagen tube as a cap for amputation neuromas, the histological and histochemical characteristics of the neuroma and spinal cord were compared with those following silicone capping. Four weeks after the transection of 18 rat sciatic nerves, the amputated neuroma was resected, and the nerve stump inserted into an atelocollagen or silicone tube. The histological changes in the nerve ends and c-fos expression in the dorsal horn of the fourth lumbar spinal cord were evaluated at 4 weeks postoperatively. The regenerated nerve structure in the atelocollagen or silicone tube was very thin. In contrast, a typical bulbous neuroma was observed in the control group (the nerve stump was left in place). The atelocollagen and silicone tube groups demonstrated fewer c-fos-expressed cells in the spinal cord than the controls. These results suggest that capping by an atelocollagen tube, like that by a silicone tube, might successfully prevent an amputated neuroma from forming, and suppress induced pain. The atelocollagen tube may be a promising biomaterial for the prevention or treatment of a painful amputation neuroma.

[Experimental study on prevention and treatment of neuroma by implanting nerve stump into muscle].

Prevention and treatment of traumatic neuroma by implanting the proximal neural stump into the muscle were studied. Sixteen SD rats were used for the experimental study. The proximal stump of the left sciatic nerve was implanted into the nearby muscle as the experiment side, whereas the proximal stump of the right sciatic nerve was left untreated as the control side. The results were assessed with histological and electrophysiological methods. The experiment demonstrated that neuroma was formed in the control side one month postoperatively, whereas in the experimental side the nerve fibers were dispersed among the muscle fibers and no definite neuroma was formed. Implantation of neural stump into muscle could prevent and treat traumatic neuroma.

Evaluation of tissue adhesive to contain axonal regeneration in horses.

Bilateral palmar and plantar digital neurectomies were completed in 10 horses (a total of 80 neurectomies) using one of three methods: (1) simple transection (guillotine method); (2) epineural capping; (3) n-butyl cyanoacrylate injected into the epineural sheath to act as a nerve sealant. Horses were regularly evaluated clinically for tenderness in and around the surgical site, as well as skin sensation at the coronary band in the heel region, during the 12-week course of the study. None of the surgical sites exhibited any signs of drainage or infection. Horses were then euthanatized, the nerve stumps were dissected from surrounding tissues, and the length and width of the tissue mass that had formed on the end of the nerve was recorded. Longitudinal and transverse sections of the nerve endings were examined histologically for numbers of proliferating axon sprouts (neuroma formation); whether the axons had penetrated the epineurium; degree of Schwann cell proliferation; degree of chronic inflammation; extent of foreign body reaction; extent of retrograde degeneration of the nerve bundles; and amount of fibrovascular proliferation. The proportion of legs exhibiting tenderness or heel sensation did not differ significantly between the three different treatments at any of the six different times they were examined. There was no difference between the three treatments in the length or width of the fibrous tissue scar on the ends of the nerves or in the number of sprouting axons from the ends of the nerves. Of 80 nerves examined, only two nerves were not confined to the epineurium.(ABSTRACT TRUNCATED AT 250 WORDS)

The inhibition of the transplacental blastomogenic effect of nitrosomethylurea by postnatal administration of buformin to rats.

N-Nitrosomethylurea (NMU) (20 mg/kg) was i.p. administered to rats on the 21st day of pregnancy. A decrease of glucose utilisation in the oral glucose tolerance test was found in 3 month old female progeny of NMU-treated rats. The serum insulin level did not differ from control, but serum cholesterol level was higher in offspring of NMU-treated rats. The ability of diethylstilboestrol to inhibit compensatory ovarian hypertrophy was decreased in female hemicastrated 3 month old rats whose mothers were treated with NMU. Postnatal administration of the antidiabetic drug buformin decreased the malignant neurogenic tumor incidence 3.5 times (to rats transplacentally treated with NMU).

Chemotherapeutic effects of some alkylating derivatives of nitrosourea on the development of tumors transplacentally induced in rats by ENU.

The application of BCNU, CCNU and MeCCNU has been shown to greatly reduce the number of tumors induced in rats by transplacentally administered ENU and to inhibit the full development of tumor proliferation. Moreover, no neurinomas appeared after treatment with CCNU. The application of GCNU proved to be much less effective. Our statistics in the form of tables showing these findings are included and discussed.