Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty Using a Preloaded Imported Graft

Purpose@#Although the popularity of Descemet membrane endothelial keratoplasty (DMEK) is increased, there is still few clinical studies in Korea. In this study, we aimed to report the initial clinical outcomes of DMEK in patients followed up for more than 6 months. @*Methods@#A total of 96 eyes that underwent DMEK by a single surgeon for Fuchs endothelial corneal dystrophy, pseudophakic bullous keratopathy, or other indications were evaluated for best-corrected visual acuity (BCVA), endothelial cell density (ECD), central corneal thickness (CCT), postoperative complications, and graft survival. @*Results@#The postoperative BCVA significantly increased compared to the preoperative BCVA by 59.4% (1.00 ± 0.77 logarithm of the minimum angle of resolution vs. 0.67 ± 0.76 logarithm of the minimum angle of resolution, p < 0.001). The average preoperative ECD was 754 ± 382 cells/mm2, increasing to 1,333 ± 562 cells/mm2 at 3 months (76.8%, p < 0.001), 1,334 ± 632 cells/mm2 at 6 months (76.9%, p < 0.001), 1,121 ± 474 cells/mm2 at 12 months (48.7%, p = 0.024), and 972 ± 458 cells/mm2 at 24 months postoperatively (28.9%, p = 0.445). Compared to 3 months, the ECD declined by 15.9% at 12 months (p = 0.009) and 27.1% at 24 months postoperatively (p = 0.158). The average CCT was 675 ± 113 μm preoperatively, decreasing to 581 ± 102, 574 ± 101, and 594 ± 94 μm at 6, 12, and 24 months after DMEK, respectively (p < 0.001 between all follow-up time points). Allograft rejection was detected in three (3.1%) and 14 eyes (14.6%) underwent retransplantation at an average of 10.1 ± 8.4 months after DMEK. @*Conclusions@#DMEK is promising for maintaining corneal clarity, low postoperative complication rates, and stable graft longevity.

Mesenchymal Stem Cells Derived from Wharton’s Jelly Can Differentiate into Schwann Cell-Like Cells and Promote Peripheral Nerve Regeneration in Acellular Nerve Grafts

BACKGROUND@#Schwann cells (SCs) secrete neurotrophic factors and provide structural support and guidance during axonal regeneration. However, nearby nerves may be damaged to obtain primary SCs, and there is a lack of nervous tissue donors. We investigated the potential of Wharton’s Jelly-derived mesenchymal stem cells (WJ-MSCs) in differentiating into Schwann cell-like cells (WJ-SCLCs) as an alternative to SCs. We also examined whether implantation of WJ-SCLCsladen acellular nerve grafts (ANGs) are effective in inducing functional recovery and nerve regeneration in an animal model of peripheral nerve injury. @*METHODS@#The differentiation of WJ-MSCs into WJ-SCLCs was determined by analyzing SC-specific markers. The secretion of neurotrophic factors was assessed by the Neuro Discovery antibody array. Neurite outgrowth and myelination of axons were found in a co-culture system involving motor neuron cell lines. The effects of ANGs on repairing sciatic nerves were evaluated using video gait angle test, isometric tetanic force analysis, and toluidine blue staining. @*RESULTS@#Compared with undifferentiated WJ-MSCs, WJ-SCLCs showed higher expression levels of SC-specific markers such as S100b, GFAP, KROX20, and NGFR. WJ-SCLCs also showed higher secreted amounts of brain-derived neurotrophic factor, glial cell-derived neurotrophic factor, and granulocyte-colony stimulating factor than did WJ-MSCs.WJ-SCLCs effectively promoted the outgrowth and myelination of neurites in motor neuron cells, and WJ-SCLCs laden ANGs significantly facilitated peripheral nerve regeneration in an animal model of sciatic nerve injury. @*CONCLUSION@#WJ-MSCs were readily differentiated into WJ-SCLCs, which effectively promoted the regeneration of peripheral nerves. Transplantation of WJ-SCLCs with ANGs might be useful for assisting peripheral nerve regeneration.

Mesenchymal Stem Cells Derived from Wharton’s Jelly Can Differentiate into Schwann Cell-Like Cells and Promote Peripheral Nerve Regeneration in Acellular Nerve Grafts

BACKGROUND@#Schwann cells (SCs) secrete neurotrophic factors and provide structural support and guidance during axonal regeneration. However, nearby nerves may be damaged to obtain primary SCs, and there is a lack of nervous tissue donors. We investigated the potential of Wharton’s Jelly-derived mesenchymal stem cells (WJ-MSCs) in differentiating into Schwann cell-like cells (WJ-SCLCs) as an alternative to SCs. We also examined whether implantation of WJ-SCLCsladen acellular nerve grafts (ANGs) are effective in inducing functional recovery and nerve regeneration in an animal model of peripheral nerve injury. @*METHODS@#The differentiation of WJ-MSCs into WJ-SCLCs was determined by analyzing SC-specific markers. The secretion of neurotrophic factors was assessed by the Neuro Discovery antibody array. Neurite outgrowth and myelination of axons were found in a co-culture system involving motor neuron cell lines. The effects of ANGs on repairing sciatic nerves were evaluated using video gait angle test, isometric tetanic force analysis, and toluidine blue staining. @*RESULTS@#Compared with undifferentiated WJ-MSCs, WJ-SCLCs showed higher expression levels of SC-specific markers such as S100b, GFAP, KROX20, and NGFR. WJ-SCLCs also showed higher secreted amounts of brain-derived neurotrophic factor, glial cell-derived neurotrophic factor, and granulocyte-colony stimulating factor than did WJ-MSCs.WJ-SCLCs effectively promoted the outgrowth and myelination of neurites in motor neuron cells, and WJ-SCLCs laden ANGs significantly facilitated peripheral nerve regeneration in an animal model of sciatic nerve injury. @*CONCLUSION@#WJ-MSCs were readily differentiated into WJ-SCLCs, which effectively promoted the regeneration of peripheral nerves. Transplantation of WJ-SCLCs with ANGs might be useful for assisting peripheral nerve regeneration.

Generation of tonsil organoids as an ex vivo model for SARS-CoV-2 infection

Palatine tonsil (hereinafter referred to as "tonsil") plays role in the immune systems first line of defense against foreign pathogens. Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a worldwide pandemic since the infection was first reported in China in December 2019. The aim of this study was to establish tonsil epithelial cell-derived organoids and to examine their feasibility as an ex vivo model for SARS-CoV-2 infection. Using an optimized protocol, we achieved 3D tonsil organoid culture from human tonsil tissue that reflects the distinctive characteristics of the tonsil epithelium, such as its cellular composition, histologic properties, and molecular biological features. Notably, we verified that SARS-CoV-2 can infect tonsil organoids with a robust replication efficiency. Furthermore, treatment with remdesivir, an antiviral agent, effectively protected them from viral infection. Therefore, tonsil organoids could be available for investigation of SARS-CoV-2 infection-mediated pathology and for preclinical screening of novel antiviral drug candidates. One-sentence SummaryThis study established tonsil epithelial cell-derived organoids and demonstrated their feasibility as an ex vivo model for SARS-CoV-2 infection.

The microbiome of the lung and its extracellular vesicles in nonsmokers, healthy smokers and COPD patients

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease, and bacterial infection plays a role in its pathogenesis. Bacteria secrete nanometer-sized extracellular vesicles (EVs), which may induce more immune dysfunction and inflammation than the bacteria themselves. We hypothesized that the microbiome of lung EVs might have distinct characteristics depending on the presence of COPD and smoking status. We analyzed and compared the microbiomes of 13 nonsmokers with normal spirometry, 13 smokers with normal spirometry (healthy smokers) and 13 patients with COPD by using 16S ribosomal RNA gene sequencing of surgical lung tissue and lung EVs. Subjects were matched for age and sex in all groups and for smoking levels in the COPD and healthy smoker groups. Each group included 12 men and 1 woman with the same mean age of 65.5 years. In all groups, EVs consistently showed more operational taxonomic units (OTUs) than lung tissue. In the healthy smoker and COPD groups, EVs had a higher Shannon index and a lower Simpson index than lung tissue and this trend was more prominent in the COPD group. Principal component analysis (PCA) showed clusters based on sample type rather than participants' clinical characteristics. Stenotrophomonas, Propionibacterium and Alicyclobacillus were the most commonly found genera. Firmicutes were highly present in the EVs of the COPD group compared with other samples or groups. Our analysis of the lung microbiome revealed that the bacterial communities present in the EVs and in the COPD group possessed distinct characteristics with differences in the OTUs, diversity indexes and PCA clustering.

Analysis of occlusal contact and guidance pattern during maximal intercuspal position and protrusive movement / 대한치과보철학회지

PURPOSE: The importance of occlusal contacts of the natural dentition for durability of teeth, mandibular stabilization, and restorative dentistry is well known. The purpose of this study is to analyze the occlusal contact and guidance pattern of Koreans by evaluating the static occlusion on maximal intercuspal position and measuring dynamic occlusion during straight protrusion. MATERIALS AND METHODS: The occlusal contacts at maximal interincisal position and the occlusal guidance pattern during straight protrusion of 29 subjects were recorded with shimstock foil (Whaledent, Langenau, Germany), T-Scan III (Tekscan Inc., Boston, MA, USA), polyvinylsiloxane registration material (Genie Bite, Sultan Healthcare, Hackensack, NJ, USA) and compared. Occlusal registration procedures were repeated 3 times. The position was fixed to an upright position and the head position was fixed with the Frankfurt horizontal plane paralleling the horizontal plane. Fisher's Exact Test (R-General Public License, ver. 2.14.1) and Pearson's Test were used to assess the significance level of the differences between the experimental groups (alpha=.05). RESULTS: When using shimstock foil, T-Scan III system, and polyvinylsiloxane registration material, most of the patients showed contact on anterior, premolar, and molar teeth during maximal intercuspal position. Approximately 51% of maximal intercuspal position showed anterior contact using shimstock foil. When examining the protrusive movement using shimstock foil and T-Scan III system, guidance pattern with the central incisor was the most common. CONCLUSION: During maximal intercuspal position, there were cases in which not all of the teeth showed occlusal contact. During mandibular protrusive movements, one or more maxillary central incisors frequently joined in straight protrusion and the posterior teeth were disoccluded. Therefore, the anterior teeth protect the posterior teeth, and vice versa. Thus, mutually protected occlusion should be applied when reconstructing occlusion.

Microbiological Contamination of Laboratory Mice and Rats in Korea from 2007 to 2008 / 한국실험동물학회지

In order to assess the microbiological contamination of laboratory mice and rats in Korea over the 2-year period from 2007 to 2008, we monitored animals housed in mouse and rat facilities equipped with barrier systems. In a barrier animal facility in Korea, the most important viruses in the identified pathogen were the mouse hepatitis virus (MHV) and Pasteurella (Pa.) pneumotropica, and Staphylococcus aureus was identified as the most common bacterial pathogen in Korea. The most commonly detected parasite in the identified pathogen was Trichomonas spp. in the mouse facilities and Entamoeba spp. in the rat facilities. In many cases, these pathogen-contaminated animals were genetically modified animals obtained from the university. Currently, consistent with the increased transfer of genetically modified animals between domestic and foreign animal facilities, the Pa. pneumotropica and parasites infection rates were shown to have increased as compared to those of the 2004-2006 period. Indeed, the MHV infection rate has been maintained at almost 20% in Korean animal facilities over the past 10 years. These results showed that effective quarantine programs for contaminated genetically engineered mutant mice and the monitoring of regular or irregular MHV monitoring in animal colonies should help to reduce pathogen contamination in Korean animal facilities.

Microbiological Contamination of Laboratory Mice and Rats in Korea from 2007 to 2008 / 한국실험동물학회지

In order to assess the microbiological contamination of laboratory mice and rats in Korea over the 2-year period from 2007 to 2008, we monitored animals housed in mouse and rat facilities equipped with barrier systems. In a barrier animal facility in Korea, the most important viruses in the identified pathogen were the mouse hepatitis virus (MHV) and Pasteurella (Pa.) pneumotropica, and Staphylococcus aureus was identified as the most common bacterial pathogen in Korea. The most commonly detected parasite in the identified pathogen was Trichomonas spp. in the mouse facilities and Entamoeba spp. in the rat facilities. In many cases, these pathogen-contaminated animals were genetically modified animals obtained from the university. Currently, consistent with the increased transfer of genetically modified animals between domestic and foreign animal facilities, the Pa. pneumotropica and parasites infection rates were shown to have increased as compared to those of the 2004-2006 period. Indeed, the MHV infection rate has been maintained at almost 20% in Korean animal facilities over the past 10 years. These results showed that effective quarantine programs for contaminated genetically engineered mutant mice and the monitoring of regular or irregular MHV monitoring in animal colonies should help to reduce pathogen contamination in Korean animal facilities.

Paradoxical Deterioration of Intramedullary Spinal Tuberculomas during Antituberculous Therapy

"Paradoxical deterioration" during antituberculous therapy is generally defined as the clinical or radiological worsening of pre-existing tuberculous lesions or the development of new lesions in a patient who initially improves. The phenomenon of paradoxical deterioration in intramedullary tuberculoma of the spinal cord is rare and is a less established entity. The authors present an unusual case of paraparesis as a result of paradoxical deterioration of intramedullary tuberculoma despite adequate antituberculous therapy. Here, we review the relevant literatures and discuss its possible pathogenic mechanisms.

Bilateral Traumatic Hemorrhage of the Basal Ganglia

Bilateral traumatic hemorrhage of the basal ganglia is an extremely rare neuropathologic entity. This report describes a 50-year-old man with bilateral basal ganglia hemorrhage with occipital fracture of the skull after head trauma. The mechanism of development of traumatic hemorrhage of the basal ganglia has been not clear. But, it is presumed to be secondary to rupture of the lenticulostriate or anterior choroidal artery by shearing as a result of acceleration/deceleration forces. We briefly summarize our uncommon case and discuss its possible mechanisms.

Spinal Cord Compression as Initial Presentation of Follicular Thyroid Carcinoma

Follicular thyroid carcinoma with metastasis rarely manifests as spinal cord compression without any previous symptoms of its malignancy. This report describes a 64-year-old man with follicular thyroid carcinoma who presented initially with left arm motor weakness. Magnetic resonance images demonstrated severe cervical cord compression by a mass with destruction of C4 vertebra. Corpectomy of C4 and anterior interbody fusion was carried out. Histopathological study revealed a metastatic follicular carcinoma of the thyroid. We present our case, especially focused of its possible pathophysiology, with review of pertinent literatures.