Foetal wounds are unique in their ability to heal rapidly without forming scars. The amniotic fluid, rich in nutrients, growth factors, and hyaluronic acid, surrounds the foetus and is essential to foetal wound healing. The wound healing properties of foetal wounds may be the result of high concentrations of hyaluronic acid. This study aimed to verify that amniotic fluid induces re-epithelialisation in human skin wounds in vitro and to study whether this ability is dependent on hyaluronic acid. Standard deep dermal wounds were produced in vitro in human skin. The skin samples, with a central wound, were incubated in different culture media. Varying concentrations of amniotic fluid and amniotic fluid with added hyaluronidase were tested, and re-epithelialisation was assessed at 3, 7, and 12 days using light microscopy, after staining with haematoxylin and eosin. Amniotic fluid 50% resulted in a significantly higher (p < 0.05) grade of re-epithelialisation than Dulbecco's modified Eagle's medium and 10% amniotic fluid at all time points. When 50% amniotic fluid was compared with 10% foetal calf serum, no significant difference was found in grades of re-epithelialisation on days 3 and 12 and significantly higher grades of re-epithelialisation on day 7 (p < 0.05). Degradation of hyaluronic acid in the medium that contained 50% amniotic fluid gave significantly impaired re-epithelialisation (p < 0.05) on culture days 3 and 7. In conclusion, amniotic fluid promotes accelerated re-epithelialisation and hyaluronic acid is an important ingredient.

Spinal cord surgery to restore motor trajectories.

Following a median nerve injury (1-11 years after injury) there may be an initial increase in the volume of the cortical representation, which subsequently declines during the restoration phase. These dynamic changes may involve both median and ulnar nerve cortical representation, because both showed negative correlation with time after injury. These findings are in agreement with animal studies showing that cortical plasticity is an important mechanism for functional recovery after peripheral nerve injury and repair.

Background: Injuries to the ulnar nerve at or above proximal forearm level result in poor recovery despite early microsurgical repair, especially concerning the intrinsic motor function of the hand. To augment the numbers of regenerating axons into the targeted muscles, a nerve transfer of the distal branch of the median nerve, the anterior interosseous nerve, to the ulnar motor branch has been described. Methods: Two patients with severe atrophy of the intrinsic hand muscles following an initial proximal ulnar nerve repair had surgery with an end-to-side transfer of the anterior interosseous nerve to the ulnar motor branch at the wrist level. Outcome and neuroplasticity were prospectively studied using questionnaires, clinical examinations, electroneurography, electromyography, somatosensory evoked potentials at pre nerve transfer and 3-, 12-, and 24-months post nerve transfer as well as navigated transcranial magnetic stimulation at pre nerve transfer and 3- and 12-months post nerve transfer. Results: Successively improved motor function was observed. Complete reinnervation of intrinsic hand muscles was demonstrated at 12- to 24-months follow-up by electroneurography and electromyography. At the cortical level, navigated transcranial magnetic stimulation detected a movement of the hot-spot for the abductor digiti mini muscle, originally innervated by the ulnar nerve and the size of the area from where responses could be elicited in this muscle changed over time, indicating central plastic processes. An almost complete reinnervation of the pronator quadratus muscle was also observed. Conclusion: Both central and peripheral plastic mechanisms are involved in muscle reinnervation after anterior interosseous nerve transfer for treatment of proximal ulnar nerve injuries.