A Study on the Monitoring of Toxocara spp. in Various Children's Play Facilities in the Republic of Korea (2016-2021).

Toxocara spp. is a zoonotic soil-transmitted parasite that infects canids and felids, which causes toxocariasis in humans, migrating to organ systems, including the lungs, the ocular system, and the central nervous system. Since Toxocara spp. is usually transmitted through soil, children tend to be more susceptible to infection. In order to monitor contamination with Toxocara spp. in children's play facilities in the Republic of Korea, we investigated 11,429 samples of soil from daycare centers, kindergartens, elementary schools, and parks across the country from January 2016 to December 2021. Since the Environmental Health Act in the Republic of Korea was enacted in March 2008, there have been sporadic reports of contamination by Toxocara spp. in children's activity zones. In this study, soil from children's play facilities in regions across the Republic of Korea was monitored according to the Korean standardized procedure to use it as basic data for preventive management and public health promotion. The national average positive rate was 0.16% (18/11,429), and Seoul showed a higher rate of 0.63% (2/318) than any other regions while Incheon, Daegu, Ulsan, Kangwon-do, Jeollabuk-do, and Jeollanam-do were negative (p < 0.05). The positive rates were as follows: 0.37% (4/1089) in daycare centers, 0.13% (3/2365) in kindergartens, 0.2% (7/4193) in elementary schools, 0.09% (1/1143) in apartments, and 0.14% (3/2198) in parks. In addition, it was confirmed that 0.2% (1/498) of elementary schools and 1.17% (2/171) of parks were re-contaminated among play facilities managed with the establishment of a regular inspection cycle. Consequently, there is an essential need for continuous monitoring of Toxocara spp. contamination and regular education for preschool and school children in order to prevent soil-borne parasite infections.

Establishment of an Acanthamoeba keratitis mouse model confirmed by amoebic DNA amplification.

Acanthamoeba castellanii, the causative agent of Acanthamoeba keratitis (AK), occurs mainly in contact lens users with poor eye hygiene. The findings of many in vitro studies of AK, as well as the testing of therapeutic drugs, need validation in in vivo experiments. BALB/c mice were used in this study to establish in vivo AK model. A. castellanii cell suspensions (equal mixtures of trophozoites and cysts) were loaded onto 2-mm contact lens pieces and inserted into mouse eyes that were scratched using an ophthalmic surgical blade under anesthesia and the eyelids of the mice were sutured. The AK signs were grossly observed and PCR was performed using P-FLA primers to amplify the Acanthamoeba 18S-rRNA gene from mouse ocular tissue. The experimental AK mouse model was characterized by typical hazy blurring and melting of the mouse cornea established on day 1 post-inoculation. AK was induced with at least 0.3 × 105 A. castellanii cells (optimal number, 5 × 104), and the infection persisted for two months. The PCR products amplified from the extracted mouse eye DNA confirmed the development of Acanthamoeba-induced keratitis during the infection periods. In conclusion, the present AK mouse model may serve as an important in vivo model for the development of various therapeutic drugs against AK.

Cytopathic Change and Inflammatory Response of Human Corneal Epithelial Cells Induced by Acanthamoeba castellanii Trophozoites and Cysts.

Acanthamoeba castellanii has ubiquitous distribution and causes primary acanthamoebic keratitis (AK). AK is a common disease in contact lens wearers and results in permanent visual impairment or blindness. In this study, we observed the cytopathic effect, in vitro cytotoxicity, and secretion pattern of cytokines in human corneal epithelial cells (HCECs) induced by A. castellanii trophozoites and/or cysts. Morphological observation revealed that panked dendritic HCECs co-cultured with amoeba cysts had changed into round shape and gradually died. Such changes were more severe in co-culture with cyst than those of co-cultivation with trophozoites. In vitro cytotoxicity assay revealed the highest cytotoxicity to HCECs in the co-culture system with amoeba cysts. A. castellanii induced the expression of IL-1α, IL-6, IL-8, and CXCL1 in HCECs. Secreted levels of IL-1α, IL-6, and IL-8 in HCECs co-cultured with both trophozoites and cysts were increased at an early incubation time (3 and 6 hr). These results suggested that cytopathic changes and pro-inflammatory cytokines release of HCECs in response to A. castellanii, especially amoebic cysts, are an important mechanism for AK development.

Correction of Severely Contracted Nose.

BACKGROUND: Severely contracted nose is manifested with a tight and hardened nasal envelope. Expansion of the contracted skin is an important first step in correcting these revision cases. The underlying weak lower lateral cartilage makes the tip projection structurally difficult to achieve and maintain without rigid supporting cartilage grafting. METHODS: A total 59 of patients were treated with isolated adipose-derived stromal cells before revision surgery to soften the nasal envelope. Adipose tissues were digested at 37°C with sterile 0.075% collagenase type 2. The average isolated adipose-derived stromal cell count of each serial injection was 5 × 10 cells (total injection volume, 0.5 ml; 1 × 10 cells/ml). Intraoperatively, the lower lateral cartilage was released from surrounding scar tissue to allow for advancement. Rib cartilage and other autologous grafts were used in reconstruction of the internal framework. RESULTS: The follow-up period ranged from January of 2009 to April of 2014. The mean follow-up period was 10 months. Fifty-one of 59 patients were satisfied with their results. Eight patients underwent revision surgery for the following: infection (two patients), deviation (one patient), warping (two patients), and cosmetic dissatisfaction (three patients). There were two cases of additional warping, but the patients refused revision surgery. Nine patients required additional adipose-derived stromal cell injections at the tip. CONCLUSIONS: The combination of isolated fat grafting to soften the nasal skin envelope and rigid tip support results in correction of silicone-induced contracted nose. There were no incidences of recurrent nasal contraction or ischemic injury. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Multilevel nonvolatile small-molecule memory cell embedded with Ni nanocrystals surrounded by a NiO tunneling barrier.

Four-level nonvolatile small-molecule 4F(2) memory cells were developed with a sandwiched device structure consisting of an upper Al electrode, upper small-molecule layer (Alq(3), aluminum tris(8-hydroxyquinoline)), Ni nanocrystals surrounded by NiO tunneling barrier, lower small-molecule layer, and bottom Al electrode. In particular, an in situ O(2)-plasma oxidation process following Ni evaporation was developed to produce uniformly stable 10 nm Ni nanocrystals surrounded by a NiO tunneling barrier embedded in the small-molecule layer. They presented a memory margin (I(on)/I(off) ratio) of approximately 1 x 10(3), a retention time of more than 10(5) s, an endurance of more than 5 x 10(2) erase-and-program cycles, and multilevel cell (MLC) operation, being a terabit nonvolatile memory-cell. A vertically double-stacked 4F(2) multilevel nonvolatile memory cell was also developed, showing a memory margin of approximately 1 x 10(3) in both the top and bottom memory cells and eight-level cell operation.