Background: Seroprevalence studies of coronavirus disease 2019 (COVID-19) from many countries have shown that the number of undiagnosed missing cases is much larger than that of confirmed cases, irrespective of seroprevalence levels. Considering the strategy of Korea entailing massive testing and contact tracing from the beginning of epidemic, the number of undiagnosed missing cases in Korea may be negligible. This study was conducted to estimate the seroprevalence of COVID-19 among individuals who were never diagnosed with COVID-19 in Daegu, the epicenter of COVID-19 epidemic in Korea. Methods: Serologic testing for immunoglobulin G antibody based on immunochromatographic assay was conducted in 103 patients and 95 guardians aged 18 to 82 years without any history of COVID-19 diagnosis, who visited outpatient clinics of a single university-affiliated hospital from May 25 to June 5, 2020. Results: The estimated seroprevalence was 7.6% (95% confidence interval, 4.3%-12.2%) with 15 positive cases. Among them, only one had a polymerase chain reaction (PCR)-confirmed case among their close contacts and 13 did not experience COVID-19-related symptoms. Seroprevalence was similar between patients and guardians. Based on this figure, the number of undiagnosed missing cases in Daegu was estimated to be a dozen times more than the number of confirmed cases based on PCR testing. Conclusion: Despite the limitation of a small and unrepresentative sample, this is the first study on seroprevalence of COVID-19 in Korea. Our study suggested that the number of undiagnosed missing cases was substantial even with the stringent strategy adopted in Korea, similar to that of other countries.

Background In osteoporotic vertebral compression fractures, supplementation using vitamin D preparations and maintenance of blood vitamin D level within the normal range are necessary for proper fracture union, enhancement of muscle strength, and maintenance of body balance. The purpose of this study is to investigate the effects of vitamin D supplementation on blood vitamin D level, pain relief, union time, and functional outcome in patients with osteoporotic vertebral compression fracture and vitamin D deficiency. Methods One hundred thirty patients who were deficient in blood vitamin D level and had osteoporotic vertebral compression fracture were divided into supplementation group and non-supplementation group. Initially, 3 months, 6 months, and 12 months after the injury, radiographs were taken to assess fracture union, and questionnaires were evaluated to evaluate the functional outcome and quality of life. Results The mean age of the 130 patients (36 males and 94 females) was 74.75 ± 7.25 years. There were no statistically significant differences in initial severity of low back pain, functional outcome, and quality of life between the insufficient group and the deficient group (all p values were > 0.05). There was no significant time-by-group interaction between the supplementation group and the non-supplementation group (p = 0.194). In terms of SF-36 physical component score, there was no significant time-by-group interaction between the supplementation group and the non-supplementation group (p = 0.934). Conclusions Fracture union was achieved in all patients regardless of serum vitamin D level, and there were significant improvements in severity of low back pain, functional outcome, and quality of life over 12 months in patients with osteoporotic vertebral compression fracture. Short-term vitamin D supplementation of patients with osteoporotic vertebral compression fracture and deficiency of vitamin D did not result in significant differences in fracture union status, functional outcome, and quality of life between the supplementation groups and the non-supplementation groups of patients.

It is well known that the worldwide demands for crops and biomass exceed their supply due to the rapid growth of world population, limitation of cultivation areas, global warming, climate change and subsequent lack of water supply. Herbicides for weeds control have played an important role in promoting productivity of crops yields and biomass. 1 Even though a number of herbicides have been developed for weeds control, more eco-friendly new herbicides having new modes of action are needed because of the environmental safety issues and occurrence of resistant weeds. 2,3 Recently, a new isoxazoline herbicide methiozolin possessing thiophene ring for the control of grass weeds in turf grass has been commercialized. 4,5 Methiozolin shows not only excellent herbicidal efficacy toward several grass weeds in turf grass but also favorable toxicological and environmental profiles. Methiozolin has one chiral center in isoxazoline ring. Up to now, methiozolin has been developed as a racemate.However, it was reported that, in many cases, big differences in biological activities between enantiomers of chiral agrochemicals have been observed. 6-8 In addition, success stories for the commercialization of chiral agrochemicals such as (S)-metolachlor 9 and mefenoxam 10 as a single isomer by Syngenta prompted us to investigate herbicidal activities of each enantiomer of methiozolin. In our previous paper, 11 the absolute stereochemistry of one enantiopure intermediate with posititive value of specific optical rotation, which is the key intermediate for synthesis of optically active methiozolin, was determined by single crystal X-ray diffraction analysis after prep-HPLC separation with chiral stationary phase [(R,R)-WHELK-O1 column] using [5-methyl-3-(3-methylthiophen-2-yl)-4,5-dihydroisoxazol-5-yl]methanol as the racemic mixture. Herein, we want to describe synthesis of enantiopure methiozolins and compare herbicidal activities between optical isomers on some grass weeds under a greenhouse condition.Key intermediates (S)-3 and (R)-3 for enantiopure methiozolins could be obtained by chiral separation of a racemic

BackgroundIn osteoporotic vertebral compression fractures, supplementation using vitamin D preparations and maintenance of blood vitamin D level within the normal range are necessary for proper fracture union, enhancement of muscle strength, and maintenance of body balance. The purpose of this study is to investigate the effects of vitamin D supplementation on blood vitamin D level, pain relief, union time, and functional outcome in patients with osteoporotic vertebral compression fracture and vitamin D deficiency.Methods130 patients who deficient blood vitamin D level and had osteoporotic vertebral compression fracture were divided into a supplementation group and non-supplementation group. At initial, 3 months, 6 months and 12 months after the injury, radiographs were taken to assess fracture union, and questionnaire were evaluated to evaluate the functional outcome and quality of life.ResultsThe mean age of the 130 patients (36 males and 94 females) was 74.75 ± 7.25 years. There were no statistically significant differences in initial severity of low back pain, functional outcome, and quality of life between the insufficient group and deficient group (all p values were >0.05). There was no significant time-by-group interaction between the supplementation group and non-supplementation group (p = 0.194). In terms of SF-36 physical component score, there was no significant time-by-group interaction between the supplementation group and non-supplementation group (p = 0.934).ConclusionsFracture union was achieved in all patients regardless of serum vitamin D level, and there were significant improvements in severity of low back pain, functional outcome, and quality of life over 12 months in patients with osteoporotic vertebral compression fracture. Short-term vitamin D supplementation of patients with osteoporotic vertebral compression fracture and deficiency of vitamin D did not result in significant differences in fracture union status, functional outcome, and quality of life between the supplementation groups and non-supplementation groups of patients

Purpose: We have analyzed the surgical outcomes of primary total knee arthroplasty (TKA) using computer-assisted (CA) navigation in terms of postoperative coronal alignment depending on preoperative lateral femoral bowing. Methods: We conducted a retrospective study of patients who have undergone navigated primary TKA from January 2016 through January 2020. Two hundred and ninety-nine cases with lateral femoral bowing of 3° or less were assigned to group 1, 95 cases of lateral femoral bowing between 3° and 5° were assigned to group 2, and 89 cases with lateral femoral bowing of more than 5° were assigned to group 3. The postoperative mechanical hip–knee–ankle (mHKA) angle was measured from scanograms, which were taken 3 months after surgery. The appropriate range of coronal alignment was set as 0 ± 3°. Results: The number of outliers of mHKA occurred was 31 cases (10.4%) in group 1, 17 cases (17.9%) in group 2, and 17 cases (19.1%) in group 3. There was a significant correlation between the degree of lateral femoral bowing and the occurrence rate of mHKA outliers. Multiple variables logistic regression analysis showed occurrence rate of outliers in group 3 to be 2.04 times higher than group 1. After adjusting the patient’s age, sex, body mass index, and preoperative HKA deformity, the occurrence rate of outliers in group 3 was still 1.96 times higher than group 1. Conclusion: The benefit of CA navigation during TKA in obtaining coronal alignment within 0 ± 3° may be lessened when the preoperative lateral femoral bowing is severely advanced.

Study Design: Retrospective study with prospectively collected data. Objective: The purpose of this study is to investigate the difference in fusion rate and clinical outcome of patients with local bone as filler for the graft and demineralized bone matrix (DBM) plus only the cancellous bone from local bone as a filler for cage in 1-level posterior lumbar interbody fusion (PLIF) with cage. Summary of Background Data: Cancellous bone is more advantageous than cortical bone in the local bone for improving bone formation in spine fusion surgery. There are little studies on the difference in fusion rate and reduction of fusion time using only these cancellous bones. Methods: Of the 40 patients who underwent 1-level PLIF using cage, 20 patients in group A used local bone and 20 patients in group B used mixture of cancellous bone extracted separately from local bone and commercially available DBM as filler for cage. Changes in fusion rate and intervertebral spacing were measured using lateral radiography, and fusion was determined as nonunion using the Brantigan-Steffee classification. The clinical outcome was evaluated. Results: There was no difference in height change over time between the two groups. Regarding union grade, group B showed better union grade than group A. However, no difference in union grade change over time was observed between the 2 groups. In group B, Oswestry Disability Index (ODI), Rolland-Morris Disability Questionnaire (RMDQ), and SF-36 mental component score (MCS) significantly decreased, but there was no difference in change over time. Conclusions: In 1-level PLIF for degenerative lumbar disease, better fusion rate was observed in the group that used only cancellous bone from local bone plus DBM than that in the group that used local bone; however, there was no difference in fusion grade change over time in the 2 groups.

Background: This study aimed to investigate the relationship between the time from injury to surgery and the degree of fracture reduction in patients with unstable thoracolumbar burst fractures who had ligamentotaxis in a surgery in which the internal fixator was removed after obtaining union of the fractures. The surgery included posterior instrumentation with pedicle screws without an intervertebral fusion. Methods: Ninety-five patients underwent posterior instrumentation that used pedicle screws without segmental fusion as well as a removal procedure for internal fixation after obtaining union of the fracture. Those patients who were followed up for at least 1 yr after removal surgery were retrospectively enrolled. At the time of the injury, vertebral body angle was measured and the difference in the two angles was termed the correction angle. Based on the duration from injury to surgery, the patients were divided into two groups: those who had surgery within 48 hr (group A) and those who had surgery after 48 hr (group B). Results: There was a significantly weak negative correlation between the correction angle and the length of time from injury to surgery when the correlation coefficient was r=−0.205. By correcting the age, correction angle, and gender as well as increasing the correction angle by 1 degree, the probability of a subject belonging to group A was increased by 1.137 times more than the probability of a subject belonging to group B (P=0.004). Conclusions: The time from the injury to surgery for unstable thoracolumbar burst fractures tends to be shorter with a younger age, and the shorter lead time will cause a weaker negative relationship with correction angle. Level of Evidence: Level III.

PurposeWe evaluated the clinical and radiographic midterm results of primary total hip arthroplasty (THA) using a 36 mm diameter femoral head on 1st generation highly cross-linked polyethylene (HXLPE) in patients 50 years and less with minimum five year follow-up.Materials and MethodsWe retrospectively reviewed 31 patients (41 hips) aged 50 years and less underwent primary THA with a 36 mm diameter femoral head on HXLPE between 2004 and 2010. Clinical follow-ups included specific measurements like modified Harris hip scores (HHS) and Merle d'Aubigne and Postel score. For radiologic evaluations, together with position of acetabular cup at six weeks later of postoperation, we separately calculated the penentrations of femoral head into polyethylene liners during postoperation and one year later check-ups, and during one year later check-ups and final check-ups.ResultsThere were no major complications except for one case of dislocation. Average modified HHS at final follow-up was 88 (81-98), and Merle d'Aubigne and Postel scores were more than 15. Mean acetabular cup inclination and anteversion were 45.81°(36.33°-54.91°) and 13.26°(6.72°-27.71°), respectively. Average femoral head penetration of steady-state wear rate determined using radiographs taken at one-year postoperatively and at latest follow-up was 0.042±0.001 mm/year.ConclusionBased on minimum 5 years clinical results, we think 36 mm metal head coupling with HXLPE as the good alternate articulation surface when planning THA for patients aged 50 years and less.