C-Yoon Kim

Neurologic foundations of spinal cord fusion (GEMINI)

Cephalosomatic anastomosis has been carried out in both monkeys and mice with preservation of brain function. Nonetheless the spinal cord was not reconstructed, leaving the animals unable to move voluntarily. Here we review the details of the GEMINI spinal cord fusion protocol, which aims at restoring electrophysiologic conduction across an acutely transected spinal cord. The existence of the cortico-truncoreticulo-propriospinal pathway, a little-known anatomic entity, is described, and its importance concerning spinal cord fusion emphasized. The use of fusogens and electrical stimulation as adjuvants for nerve fusion is addressed. The possibility of achieving cephalosomatic anastomosis in humans has become reality in principle.

Accelerated recovery of sensorimotor function in a dog submitted to quasi-total transection of the cervical spinal cord and treated with PEG.

Background: A case report on observing the recovery of sensory-motor function after cervical spinal cord transection. Case Description: Laminectomy and transection of cervical spinal cord (C5) was performed on a male beagle weighing 3.5 kg. After applying polyethylene glycol (PEG) on the severed part, reconstruction of cervical spinal cord was confirmed by the restoration of sensorimotor function. Tetraplegia was observed immediately after operation, however, the dog showed stable respiration and survival without any complication. The dog showed fast recovery after 1 week, and recovered approximately 90% of normal sensorimotor function 3 weeks after the operation, although urinary disorder was still present. All recovery stages were recorded by video camera twice a week for behavioral analysis. Conclusion: While current belief holds that functional recovery is impossible after a section greater than 50% at C5-6 in the canine model, this case study shows the possibility of cervical spinal cord reconstruction after near-total transection. Furthermore, this case study also confirms that PEG can truly expedite the recovery of sensorimotor function after cervical spinal cord sections in dogs.

Immunohistochemical evidence of axonal regrowth across polyethylene glycol-fused cervical cords in mice

It is generally accepted that a severed spinal cord is associated with permanent paralysis. Recently, a spinal cord fusion protocol (GEMINI) has been proposed, whereby an acutely controlled, sharp, operative transection of the spinal cord is carried out. This scenario is not comparable (even in principle) to the clinical situation of a traumatic spinal cord injury, in which major tissue disruption (mechanical, hemorrhagic, scarand cyst-associated) occurs (Canavero, 2015). During 1950s–1960s, neurosurgeon Dr. Freeman made extensive observations of what happens when a spinal cord is sharply transected. He reported slow recovery of behavioral motor function in several animals over months (reviewed in Canavero et al., 2016), with clear signs of electrophysiological conduction. Most importantly, silver stained histologic sections showed numerous growing axons connecting the divided ends (Freeman, 1963). This recovery can be accelerated by treating the severed cord with a fusogen (e.g., polyethylene glycol) (see for full discussion and rationale from Canavero, 2013; Kim, 2016). Here, we clearly prove that axonal regrowth is possible across the severance interface using immunohistochemistry and electron microscopy. The experiment was approved by the Institutional Animal Care and Use Committee of the Konkuk University (Seoul, Korea). Our previous experiment reported a mild recovery of the limb to the level of a sweeping behavior without weight support at the 4 week after C5 laminectomy, equal to a Basso, Beattie and Bresnahan (BBB) locomotor scale score of 6–8 (Kim et al., 2016), and aiming at confirming the possibility of direct reconnection of a fully severed spinal cord. In this model, reproducing traumatic severance with a blade as happens after clinical stab wounds, no gap exists between the severed stumps. In this study, to confirm neuroregeneration across the contact interface, C5 laminectomy was performed in female ICR mice as described previously (Kim et al., 2016). After gently raising the cervical cord with a hook, complete severance was performed with surgical sharp blades #11. Polyethylene glycol (PEG MW 400, Sigma-Aldrich, St. Louis, MO, USA), a cell membrane fusogen (Ye et al., 2016)) was dripped onto the cut area. After the muscle and fascia were sutured and the skin closed, normal saline solution was provided with total parenteral nutrition (TPN, Chong Kun Dang, Korea) through the tail vein four times a day. All mice sacrificed at 4 weeks after operation showed partial behavior recovery as reported in a previous study (Kim et al., 2016). The spinal cervical cords were removed, frozen on dry ice and sectioned into longitudinal and transverse slices. Sections were fixed with 4% paraformaldehyde solution. Fixed sections were immunohistochemically stained for anti-neurofilament 200 (NF200; Sigma, 1:50), and mounted with 4′,6-diamidino-2-phenyindole (DAPI). Fluorescence was visualized using fluorescence or confocal microscopy. The transverse slices of fixed tissue were examined by transmission electron microscopy

First detection of West Nile virus in domestic pigeon in Korea

West Nile virus (WNV) is a mosquito-borne zoonotic pathogen that has spread throughout Europe and the United States. Recently, WNV spread to East and Southeast Asia, and great efforts have been made in South Korea to prevent the spread of WNV from neighboring countries. In this study, we diagnosed the first case of WNV in pigeons (Columba livia domestica) residing in cities using a competitive enzyme-linked immunosorbent assay and confirmed it with nested reverse transcription polymerase chain reaction analysis and sequencing. This is the first report to provide convincing evidence that WNV is present within South Korea.

Detection and Molecular Characterization of Cryptosporidium spp. from Wild Rodents and Insectivores in South Korea

In order to examine the prevalence of Cryptosporidium infection in wild rodents and insectivores of South Korea and to assess their potential role as a source of human cryptosporidiosis, a total of 199 wild rodents and insectivore specimens were collected from 10 regions of South Korea and screened for Cryptosporidium infection over a period of 2 years (2012-2013). A nested-PCR amplification of Cryptosporidium oocyst wall protein (COWP) gene fragment revealed an overall prevalence of 34.2% (68/199). The sequence analysis of 18S rRNA gene locus of Cryptosporidium was performed from the fecal and cecum samples that tested positive by COWP amplification PCR. As a result, we identified 4 species/genotypes; chipmunk genotype I, cervine genotype I, C. muris, and a new genotype which is closely related to the bear genotype. The new genotype isolated from 12 Apodemus agrarius and 2 Apodemus chejuensis was not previously identified as known species or genotype, and therefore, it is supposed to be a novel genotype. In addition, the host spectrum of Cryptosporidium was extended to A. agrarius and Crosidura lasiura, which had not been reported before. In this study, we found that the Korean wild rodents and insectivores were infected with various Cryptosporidium spp. with large intra-genotypic variationa, indicating that they may function as potential reservoirs transmitting zoonotic Cryptosporidium to livestock and humans.

P‐1: A New TFT‐LCD Panel Structure with High Aperture Ratio and Small Signal Delay by fabrication TFT in Line‐Crossover

We have proposed and fabricated a poly-Si TFT integrated gate-data line-crossover structure in order to increase the aperture ratio and to reduce the signal delay. The poly-Si TFT is integrated in the gate-data line-crossover without sacrificing the electrical characteristics so that the aperture ratio of the panel was improved by about 3% because the TFT is located under a metal line. We employ a low dielectric air-gap between the gate-data line crossover, which reduces the capacitance between the gate and the data lines, so that the signal delay of the data line is decreased significantly. The fabricated TFT was successfully operated, and the proposed structure reduces the delay time by about 9 times compared with the conventional panel that does not employ any air-bridges.

An outbreak of toxoplasmosis in squirrel monkeys (Saimiri sciureus) in South Korea

Toxoplasma gondii (T. gondii) is an intracellular protozoan parasite that can infect warm‐blooded animals including humans. New World monkeys, such as squirrel monkeys, are more susceptible to T. gondii than Old World monkeys, often developing fatal disease.

Improved Transfection Efficiency and Metabolic Activity in Human Embryonic Stem Cell Using Non-Enzymatic Method

Human embryonic stem cells (hESCs) are pluripotent cells widely used in conventional and regenerative medicine due to their ability to self-renew, proliferate and differentiate. Recently, genetic modification of stem cells using genome editing is the most advanced technique for treating hereditary diseases. Nevertheless, the low transfection efficiency of hESCs using enzymatic methods is still limited in in vitro preclinical research. To overcome these limitations, we have developed transfection methods using non-enzymatic treatments on hESCs. In this study, hESCs were transfected following enzymatic (TrypLE and trypsin) and non-enzymatic treatment ethylenediaminetetraacetic acid (EDTA) to increase transfection efficiency. Flow cytometric analysis using an enhanced green fluorescent protein vector showed a significantly increased transfection efficiency of EDTA method compared to standard enzyme method. In addition, the EDTA approach maintained stable cell viability and recovery rate of hESCs after transfection. Also, metabolic activity by using Extracellular Flux Analyzer revealed that EDTA method maintained as similar levels of cell functionality as normal group comparing with enzymatic groups. These results suggest that transfection using EDTA is a more efficient and safe substitute for transfection than the use of standard enzymatic methods.

Data set in support of neurotoxicity of trimethyltin chloride by morphological and protein analysis

Trimethyltin chloride (TMT) is a neurotoxicant widely present in the aquatic environment. Chronic exposure of embryos to TMT for 4 days post-fertilization (dpf) elicited a concentration-related decrease in head & eye size and increase in axial malformation. In addition, Rohon-Beard sensory neurons and motor neurons showed decreased patterns of protein expression. These data coincide with previous research about the neurotoxicity of TMT on mRNA expression (Kim et al., 2016 [1]). These data demonstrates that TMT inhibits specific neurodevelopmental stages in zebrafish embryos and suggests a possible mechanism for the toxicity of TMT in vertebrate neurodevelopment. This paper contains data related to research concurrently published in Kim et al. (2016) [1].