Inadequate blood supply persists in keloids.

We have previously shown that the adenosine triphosphate (ATP) content of keloids remains high for a long time. In keloids, anaerobic glycolysis may be related to the production of ATP. In this study, we counted the vessels in keloids, hypertrophic and atrophic scars in a defined area, and measured the cross-sectional areas of their internal lumens immunohistopathologically and the lactate concentrations. The mean number in a defined area was smallest in keloids as was the mean internal area of vessels. The lactate content of keloids was 39.4 (13.5) mmol/g of protein, of red scars 23.8 (7.5), of pink scars 23.8 (7.6), and of white scars 13.3 (7.3). These results indicate that ATP may be produced by anaerobic glycolysis in keloids, and that the decreased and narrowed vessels may reduce oxygen perfusion. The blood supply to keloids is inadequate, and this persists.

5-HT2C receptor agonists attenuate pain-related behaviour in a rat model of trigeminal neuropathic pain.

Peripheral branches of the trigeminal nerve may be damaged during maxillofacial injury or surgical procedures and trigeminal trauma may induce severe pain that is very challenging to treat. Chronic constriction injury to the infraorbital nerve (ION-CCI) by loose ligatures has proven a useful model for some types of trigeminal neuropathic pain disorder. Using ION-CCI rats, we examined the antiallodynic effects of intrathecally administered agents which are selective for 5-HT2C receptors. Allodynia was evaluated by applying von Frey filaments to skin innervated by the injured ION. Dose-dependent antiallodynic effects followed administration of three 5-HT2C receptor agonists, 6-chloro-2-(1-piperazinyl)-pyrazine (MK212: 10, 30, and 100 µg); (S)-2-(chloro-5-fluoro-indol-l-yl)-1-methyamine fumarate (RO 60-0175: 10, 30, and 100 µg); (AaR)-8,9-dichloro-2,3,4,4a-tetrahydro-1H-pyrazino[1,2-a]quinoxalin-5(6H)-one (WAY-161503: 10, 30, and 100 µg). ED50 values for antiallodynic effects of MK212, RO 60-0175, and WAY-161503 were 39.62, 46.67, and 51.22 µg, respectively. Intrathecal administration of the 5-HT2C receptor antagonist, 8-[5-2,4-dimethoxy-5-(4-trifluoromethylphenylsulphonamido)phenyl-5-oxopentyl]-1,3,8-triazaspiro[4,5]decane-2,4-dione (RS-102221: 30 µg) did not alter the mechanical threshold. Intrathecal pretreatment with RS-102221 (10 and 30 µg) reduced the antiallodynic effects of the highest dose of 5-HT2C agonists. These results indicated that, in this rat model, the 5-HT2C receptor plays a role in spinal inhibition of trigeminal neuropathic pain.

P2X4 receptor expression in a rat model of trigeminal neuropathic pain.

We investigated the P2X4 receptor (P2X4R) expression in the cervical spinal cord, trigeminal ganglion, and infraorbital nerve (ION), after a chronic constriction injury of unilateral ION and a treatment with selective serotonin reuptake inhibitor (SSRI). A recent study has showed that SSRI inhibits P2X4R expression. Injured rats had significantly lower pain thresholds. In injured and slightly injured ION, the P2X4R expression was significantly higher than in the naïve-rat ION. Injured animals with SSRI showed significantly higher pain thresholds than injured animals without the drug. Nonetheless, P2X4R expression in the ipsilateral ION remained high. Immunostaining showed that macrophages are the source of P2X4R. Our results suggest that the expression of P2X4R in our model is modulated not by neuropathic pain, but by slight nerve injury.

Additional distraction osteogenesis after conventional fronto-orbital advancement.

In the conventional fronto-orbital advancement method, there is a limit to advancement because of scalp skin tension and an absence of a supraorbital bar fixating point. In a case of insufficient advancement after the primary operation, a secondary re-advancement must be performed. In such a condition, additional fronto-orbital advancement by distraction osteogenesis has proved to be very useful. The authors used additional distraction osteogenesis in three infant cases: two of nonsyndromic craniosynostosis and one of Apert's syndrome. They were able to perform these operations safely using their original internal devices. Distraction was started 3 days after the operation. The rate of advancement was 0.5 to 1.0 mm per day. The distraction distances ranged from 16 to 22 mm. They were able to gain enough advancement in all three cases. A reoperation of a fronto-orbital advancement is more difficult than the primary operation because of possible infection, much loss of blood, low blood supply to advanced bones, a tendency of advanced bones to relapse, increased scalp skin tension, and the existence of bone defects. In these poor conditions, distraction osteogenesis has many advantages: good vascularization, no relapsing, a low infection rate, and no need for bony fixating points in the bone defects. Although it is necessary to have a secondary operation to remove the devices and prolonged hospitalization is required, the disadvantages are far outweighed by the many advantages when performing additional fronto-orbital advancement.