Effect of acute limb ischaemia on neuromuscular function in rats.

OBJECTIVE: To locate the exact site of the primary lesion in the neuromuscular system in acutely ischaemic extremities. DESIGN: Experimental study. SETTING: University hospital, Greece. ANIMALS: 22 adult rats. INTERVENTIONS: Isometric tensions of extensor digitorum longus muscles were recorded before ischaemia and every 5 minutes after the arterial occlusions by indirect stimulation. When no contractile activity was elicited, the muscle was stimulated directly and recordings made every 5 minutes. The sciatic nerve function was checked by recordings of nerve conduction velocity. Specimens from the muscles were examined under electron microscopy. MAIN OUTCOME MEASURES: Muscle contractile properties, conduction velocity, and electron microscopic appearance. RESULTS: After a period of about 50 minutes neuromuscular function under indirect stimulation in the ischaemic limbs was lost, whilst under direct stimulation the extensor digitorum longus muscles and the sciatic nerves still functioned. Electron microscopic study showed distinct alterations at the neuromuscular junctions. CONCLUSIONS: The response of the neuromuscular system to acute ischaemia indicated that the neuromuscular junction is probably the site most susceptible to acute ischaemia.

The use of a dura mater patch to cover oesophageal defects of different sizes: an experimental study in chickens.

OBJECTIVE: To find out the optimal size of full thickness oesophageal defects that can be repaired with patches of Tutoplast Dura (solvent dehydrated human dura mater in the form of absorbable collagen). DESIGN: Experimental study. SETTING: Teaching hospital, Greece. MATERIAL: 96 female Hubbard chickens in four groups of 24. INTERVENTIONS: In the three experimental groups longitudinal defects were made in the cervical oesophagus 30 x 5, 10, or 15 mm and covered with Tutoplast. Subgroups of 6 chickens were weighed, had a barium swallow examination, and were then killed at 2, 4, 6, and 8 weeks. The oesophagus was removed and examined histopathologically. MAIN OUTCOME MEASURES: Weight, extent of healing macroscopically and microscopically. RESULTS: All chickens that had had defects 30 x 15 mm in size died between days 5 and 10, and the oesophagus in all cases was obstructed by food. There were no deaths or complications in the other three groups, and no evidence of dysphagia on barium swallow. In chickens with defects of 30 x 5 and 30 x 10 mm the prosthetic material gradually disappeared, and they healed well. CONCLUSIONS: Defects in the chicken's cervical oesophagus larger than 30 x 10 mm cannot be repaired with a Tutoplast patch, but smaller defects can. Further studies are needed to clarify the mechanisms of healing.