Melatonin is an endogenous indolamine, classically known as a light/dark regulator. Besides classical functions, melatonin has also showed to have a wide range of antitumoral effects in numerous cancer experimental models. However, no definite mechanism has been described to explain the whole range of antineoplasic effects. Here we describe a dual effect of melatonin on intracellular redox state in relation to its antiproliferative vs cytotoxic actions in cancer cells. Thus, inhibition of proliferation correlates with a decrease on intracellular reactive oxygen species (ROS) and increase of antioxidant defences (antioxidant enzymes and intracellular gluthation,GSH levels), while induction of cell death correlates with an increase on intracellular ROS and decrease of antioxidant defences. Moreover, cell death can be prevented by other well-known antioxidants or can be increased by hydrogen peroxide. Thus, tumour cell fate will depend on the ability of melatonin to induce either an antioxidant environment--related to the antiproliferative effect or a prooxidant environment related to the cytotoxic effect.

The presence of nerve growth factor receptors (NGFr) in sensory nerve corpuscles of human digital skin, primarily Meissner and Pacinian corpuscles, was investigated immunohistochemically using two monoclonal antibodies directed against human-NGFr. To ensure the localization of NGFr immunoreactivity (IR) alternative sections to that processed for NGFr detection were assayed for neurofilament protein (NFP) and S-100 protein which selectively label the axon and the periaxonic specialized cells (lamellar cells of Meissner's corpuscles; inner-core cells of Pacinian corpuscles), respectively. Occurrence of NGFr IR was observed in both types of sensory corpuscles. In Meissner's corpuscles NGFr-IR was found in the lamellar cells, whereas in the Pacinian corpuscles the lamellae of the inner core, outer core, and capsule displayed NGFr IR. Moreover, a positive IR was observed in the central axon of some Pacinian corpuscles. However, remarkable differences were encountered among Pacinian corpuscles in the pattern of NGFr IR distribution. Present results demonstrate the presence of NGFr IR in sensory nerve corpuscles of the human digital skin, suggesting that NGFr could be involved in the concentration of NGF and in the conveying of this molecule from the cutaneous sources to the cell body of NGF-dependent primary sensory neurons. However, the mechanisms involved in this process remain to be clarified.

Background Metatarsalgia of the lesser toes is a common cause of consultation in the podiatric clinic. However, there continues to be a controversy with respect to which is the best surgical technique, and there is few information in the literature regarding objectively comparable results in percutaneous surgery. Methods The second metatarsal bones of 30 feet belonging to patients who had attended the podiatric clinic were studied before and after distal metatarsal pecutaneous osteotomy. The degree of shortening of the second metatarsal (RX) and the degree of functional recovery and perception of the well-being of the patient (AOFAS) were evaluated retrospectively. The same bones of 10 cadaveric feet were also studied. The surgical procedure was identical to that used on patients, and electronic callipers were employed to take measurements of the second metatarsal. The integrity of the plantar plate was checked visually. Results The mean shortening of the second metatarsal bone, as determined by the radiological study, was 2.76 mm. After an average follow-up period of 1.5 years, the final mean score on the AOFAS scale was 95.26 points. In none of the cases was the mobility of the metatarsophalangeal (MTP) joint affected. The mean shortening in the cadaveric feet was 2.10 mm, and in all cases, the plantar plate and flexor apparatus were perfectly preserved. Conclusions Percutaneous osteotomy achieved, in our study, a lower degree of shortening than Weil’s surgery, according to the data published in the literature. However, it shows good clinical results without causing problems of consolidation or rigidity in the MTP joint. Neither, with the caution that should be taken due to the use of experimental cadaver models, damage of the flexor apparatus of the foot is observed. These results suggest that this could be a safe and effective surgical procedure to be considered for metatarsalgias of the lesser rays.