MPTP-induced vulnerability of dopamine neurons in A53T α-synuclein overexpressed mice with the potential involvement of DJ-1 downregulation

Familial Parkinson's disease (PD) has been linked to point mutations and duplication of the α-synuclein (α-syn) gene. Mutant α-syn expression increases the vulnerability of neurons to exogenous insults. In this study, we developed a new PD model in the transgenic mice expressing mutant hemizygous (hemi) or homozygous (homo) A53T α-synuclein (α-syn Tg) and their wildtype (WT) littermates by treatment with sub-toxic (10 mg/kg, i.p., daily for 5 days) or toxic (30 mg/kg, i.p., daily for 5 days) dose of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Tyrosine hydroxylase and Bcl-2 levels were reduced in the α-syn Tg but not WT mice by sub-toxic MPTP injection. In the adhesive removal test, time to remove paper was significantly increased only in the homo α-syn Tg mice. In the challenging beam test, the hemi and homo α-syn Tg mice spent significantly longer time to traverse as compared to that of WT group. In order to find out responsible proteins related with vulnerability of mutant α-syn expressed neurons, DJ-1 and ubiquitin enzyme expressions were examined. In the SN, DJ-1 and ubiquitin conjugating enzyme, UBE2N, levels were significantly decreased in the α-syn Tg mice. Moreover, A53T α-syn overexpression decreased DJ-1 expression in SH-SY5Y cells. These findings suggest that the vulnerability to oxidative injury such as MPTP of A53T α-syn mice can be explained by downregulation of DJ-1.

Management of the paralyzed ectropion by implanting conchal cartilage / 나학회지

Paralytic lagophthalmos and ectropion by leprosy are serious complications of facial paralysis, which may lead to exposure keratitis, corneal ulceration, and further lead to blindness. In 1995 and 1997, we reported in this journal on the surgical treatment of 38 patients and 98 patients suffering with paralytic lagophthalmos and ectropion. In the first report of 1995, for lid closing I(Ahn) performed the method of traditional surgery such as temporal muscle transfer, medial and lateral canthoplasty as well as gold implant. In the 2nd report of 1997, we(Ahn and Park) presented the results of our combination treatment that changed the design and weight of the gold plate inserted in upper lid, and the medial canthoplasty and horizontal shortening in lower lid. Combination treatment provided for near normal eye closure and aesthetically pleasing appearance without the drawbacks associated with other methods such as eye clinching in concert with mouth closure, donor site deformities resulting from temporalis muscle transfer, and over exposure of carbuncle due to stretching effects of lateral canthoplasty. We have now found that raising the level of the lower lid margin to the sclera is important in concealing the scleral show due to drooping of the lower lid. We grafted conchal cartilage in a 5 x 35 mm sized band, which was fixed at the medial and lateral canthal area in 57 patients during the recent 3 years. We also added the ancillary procedure of the horizontal shortening in cases of highly atonic lower lid. We have noted that gold implantation in the upper eyelid and cartilage graft in the lower eyelid, with optional horizontal shortening, successfully corrected the lagophthalmos and ectropion due to facial nerve palsy.