Abstract
Background
Positive results from real-time reverse-transcription polymerase chain reaction (rRT-PCR) in recovered patients raise concern that patients who recover from coronavirus disease ...2019 (COVID-19) may be at risk of reinfection. Currently, however, evidence that supports reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has not been reported.
Methods
We conducted whole-genome sequencing of the viral RNA from clinical specimens at the initial infection and at the positive retest from 6 patients who recovered from COVID-19 and retested positive for SARS-CoV-2 via rRT-PCR after recovery. A total of 13 viral RNAs from the patients’ respiratory specimens were consecutively obtained, which enabled us to characterize the difference in viral genomes between initial infection and positive retest.
Results
At the time of the positive retest, we were able to acquire a complete genome sequence from patient 1, a 21-year-old previously healthy woman. In this patient, through the phylogenetic analysis, we confirmed that the viral RNA of positive retest was clustered into a subgroup distinct from that of the initial infection, suggesting that there was a reinfection of SARS-CoV-2 with a subtype that was different from that of the primary strain. The spike protein D614G substitution that defines the clade “G” emerged in reinfection, while mutations that characterize the clade “V” (ie, nsp6 L37F and ORF3a G251V) were present at initial infection.
Conclusions
Reinfection with a genetically distinct SARS-CoV-2 strain may occur in an immunocompetent patient shortly after recovery from mild COVID-19. SARS-CoV-2 infection may not confer immunity against a different SARS-CoV-2 strain.
We conducted serial whole-genome sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our results highlight possible SARS-CoV-2 reinfection with a genetically distinct SARS-CoV-2 strain in patients shortly after recovery from mild coronavirus disease 2019 (COVID-19).
Circulating tumor DNA (ctDNA) is a promising biomarker for early tumor detection and minimal residual disease (MRD) assessment in early-stage cancer, but quantifying minute amounts of ctDNA is ...challenging and well-designed studies on ctDNA in early-stage cancer are still lacking. Here, we adapted a sensitive next-generation sequencing (NGS) technology and performed parallel analysis of pre- and postoperative ctDNA and matched tumor tissues in a prospective cohort of patients with resectable pancreatic ductal adenocarcinoma (PDAC).
In total, 70 consecutive patients undergoing curative resection for resectable PDAC were enrolled. We performed integrated digital error suppression-enhanced cancer personalized profiling by deep sequencing NGS of triple-matched samples (pre/postoperative plasma cell-free DNA cfDNA, tumor tissue, and genomic DNA) targeting 77 genes.
Preoperative ctDNA was detected in 37.7% of the evaluable patients, with a median variant allele frequency of 0.09%. Twelve additional oncogenic mutations were detected exclusively in preoperative ctDNA but not in tissue. When quantitative concentrations of ctDNA were estimated in haploid genome equivalents per milliliter (hGE/mL), the risk of early recurrence was high in patients with postoperative ctDNA >1 hGE/mL. cfDNA variants from 24.5% of patients had features compatible with clonal hematopoiesis.
An optimized NGS approach might add value beyond tissue analysis through the highly sensitive detection of minute amounts of ctDNA in resectable PDAC. Postoperative ctDNA concentration could be a tool for MRD assessment. Moreover, parallel analyses of matched tissues and leukocytes might be required to accurately detect clinically relevant ctDNA.
We compared SARS-CoV-2 detection rate of different respiratory specimens (nasopharyngeal swab NPS, n=92; oropharyngeal swab OPS, n=18; sputum, n=11). We also compared cycle threshold (Ct) values of ...paired specimen types obtained from the same patient on the same day. Then we characterized viral load kinetics of NPS (n=142), OPS (n=126), and sputum (n=75), during disease course. Sputum samples showed higher detection rate than NPS, and OPS exhibited the lowest detection rate. The median Ct values in NPS were significantly lower than in paired OPS, and higher than in paired sputum, respectively (
<0.05). During the disease course, viral load was the lowest in OPS and the highest in sputum samples.
Abstract
Background
This study aimed to assess and update the content, reliability, and information quality of content related to root canal treatment (RCTx) on YouTube and evaluate the correlation ...between each evaluation index.
Methods
YouTube was searched using two terms related to RCTx (“root canal and endodontic treatment”). A total of 240 videos (120 for each search term) were screened. Exclusion criteria were as follows: no sound or visuals, non-English, irrelevant to the search term, longer than 15 min, duplicate, or old (uploaded before 2016). After exclusion, 50 videos of “root canal treatment” and 45 videos of “endodontic treatment” were analyzed. Video length, total number of views, likes, dislikes, comments, and days since upload were recorded using descriptive video data. Viewers’ interaction, reliability and information quality of the video, and quality of video content were measured using nondescriptive video data. The interaction index and video power index were used for viewer interactions, and the modified DISCERN index, JAMA criteria, and Global Quality Score were used to assess the reliability and information quality of the video. The quality of the video content was measured using the completeness score.
Results
The videos of the “root canal treatment” group had a significantly higher completeness score for the etiology and symptoms (
p
< 0.05), and videos of the “endodontic treatment” group showed a higher interaction index, completeness score for the procedure (
p
< 0.05). Videos for dentists had significantly higher completeness scores for the procedure, while videos for laypersons had higher completeness scores for etiology, anatomy, symptoms, and prognosis (
p
< 0.05). Furthermore, the total completeness score and the interaction index of the videos for laypersons were significantly higher (
p
< 0.05). The videos uploaded by the university had a significantly higher modified DISCERN index (
p
= 0.044), and the JAMA score was significantly higher in the commercial group (
p
= 0.001).
Conclusions
Although the accuracy of videos related to RCTx was higher in videos by universities and professionals, the total completeness of YouTube videos was low regardless of the video source. Therefore, professionals should be responsible for providing more accurate and reliable videos.
Four-Week Repeated-Dose Toxicity of Silk Amino Acids in Rats Kim, T.M. (Chungbuk National University, Cheongju, Republic of Korea); Ryu, J.M. (PeerBiotech Co., Ltd., Cheongju, Republic of Korea); Seo, I.K. (PeerBiotech Co., Ltd., Cheongju, Republic of Korea) ...
Laboratory animal research,
12/2008, Letnik:
24, Številka:
4
Journal Article
Recenzirano
This study was performed to confirm the safety of the silk amino acids (SAA). Male and female Sprague-Dawley rats were orally administered with SAA at dose levels of 500, 1,000 or 2,000 mg/kg for 4 ...weeks. There was no significant difference in the body weight gain between vehicle control and SAA-treated rats. Also, significant changes in daily feed and water intakes were not observed. In hematological analysis, SAA decreased the rates of monocytes and eosinophils, while increasing that of lymphocytes, suggestive of reduced inflammatory response and immune potentiation. In particular, SAA significantly increased the numbers of red blood cells, showing microcytic erythropoiesis, and platelets, implying an enhanced hematopoiesis. In blood biochemistry, alanine transaminase, aspartate transaminase and lactate dehydrogenase were significantly reduced by SAA treatment, in contrast to the increases in glucose and albumin. Blood urea nitrogen and creatine phosphokinase also significantly decreased following SAA treatment. In spite of the decreases in the markers of liver, kidneys, skeletal and heart muscles, no remarkable lesions were observed in these organs. Such effects of SAA on the blood markers might be due to the stabilization or protective activities on the active organs, which may lead to enhanced resistance to hyperactivity, hypermotility or excitatory stress. Since no observed adverse-effect level of SAA was found to be higher than the upper-limit dose (2,000 mg/kg), a 20-fold higher level of a clinicallyrecommended dose (100 mg/kg), it is suggested that SAA possess a long-term safety, and that it could be a candidate for the improvement of hematopoiesis and stamina.
Skin Irritation and Sensitization Studies on Rosin∨_ Powder Ryu, J.M. (Peerbiotech Co., Ltd., Cheongju, Republic of Korea); Seo, I.K. (Peerbiotech Co., Ltd., Cheongju, Republic of Korea); Kim, T.M. (Peerbiotech Co., Ltd., Cheongju, Republic of Korea) ...
Laboratory animal research,
06/2008, Letnik:
24, Številka:
2
Journal Article
Recenzirano
Primary skin irritation and skin sensitization induced by Rosin∨_, an extract of pine tree, were assessed in rabbits and guinea pigs, respectively, according to the guidelines of Korea Food and Drug ...Administration. In primary skin irritation test, 5% and 10% of Rosin∨_ (in 80% ethanol) exhibited mean score 1.17 and 1.33, respectively, leading to primary irritation indices (PII) of 0.29 and 0.33. Thus, the test compound Rosin∨_ was evaluated to be a 'non-irritant' material. In skin sensitization study using guinea pig maximization test (GPMT), 5% and 10% Rosin∨_ did not induce erythema or edema, displaying sensitization score 0 and rate 0%, whereas 0.1% 2,4-dinitrochrolobenzene (DNCB), a positive control, induced sensitization scores 1-2 and rate 80%. Therefore, Rosin∨_ and DNCB were classified to grade Ⅰ and Ⅳ, indicating weak and strong sensitizers, respectively. Taken together, it is suggested that Rosin∨_ is a pratically-safe material to skin without potential of irritation or allergic sensitization.
The chemopreventive effects of Magnolia ovobata water extract (MWE) and 70% ethanol extract (MEE) on the development of colonic aberrant crypt foci (ACF) induced by 1,2-dimethylhydrazine (DMH) were ...investigated. Six-week-old male F344 rats were divided to 7 experimental groups; 1) DMH alone, 2) DMH+0.3% MWE, 3) DMH+1% MWE, 4) DMH+3% MWE, 5) DMH+1% MEE, 6) 3% MWE alone and 7) normal control. Animals were subcutaneously injected with DMH (30 mg/kg) 4 times to induce colonic ACF during the initial 2 weeks, and fed with a basal containing various concentrations of test materials (MWE or MEE) for 8 weeks including the DMH-treatment period. The formation of ACF on colonic mucosa was observed after staining with methylene blue. There are no specific effects of MWE and MEE on body weight, feed and water consumptions, organ weights, histopathological observations, and hematological and blood chemistry analyses. Challenge with DMH alone induced mean number of 270.1 ACF/colon which was somewhat inhibited by MWE treatment, showing average numbers of 234.3-242.1 ACF/colon. In comparison, the ACF number was significantly suppressed to 216.5 by administration of 1% MEE. Therefore, these results suggest that Magnolia ovobata extracts, especially MEE, exert a chemopreventive effect on the DMH-induced colon cancer by inhibiting the early development of ACF.
Effect of Repeated Administration of Silk Peptide on the Immune System of Rats Ryu, J.M. (PeerBiotech Co., Ltd., Cheongju, Republic of Korea); Kim, T.M. (PeerBiotech Co., Ltd., Cheongju, Republic of Korea); Seo, I.K. (PeerBiotech Co., Ltd., Cheongju, Republic of Korea) ...
Laboratory animal research,
09/2008, Letnik:
24, Številka:
3
Journal Article
Recenzirano
In order to elucidate the possibility of influence on the immune system, silk peptide was administered to rats for 4 weeks. Male and female Sprague-Dawley rats were orally treated with low (500 ...mg/kg) or high (2,000 mg/kg) doses of silk peptide, and complete blood counts, organ weights, histopathology and cellularity of immune systems were examined. Silk peptide did not cause clinical signs, although the body weight gain at the high dose was slightly reduced. In hematological analysis, the number of white blood cells (WBC) and differential counts, the number of red blood cells (RBC) and RBC indices, and the number of platelets and mean platelet volume (MPV) were not affected by the administration of silk peptide. Especially, there were no differences in the number and rate (%) of immune cells such as lymphocytes as well as monocytes and granulocytes between vehicle and silk peptide-treated groups. Silk peptide neither affected the thymus and spleen weights, in addition to the cellularity in thymus, nor induced gross and microscopic lesions of thymus, spleen and lymph node. Taken together, 4-week administration of silk peptide up to 2,000 mg/kg, the upper-limit dose in repeated-dose toxicity study, did not exhibit adverse effects on the immune systems, leading to no observed adverse effect level (NOAEL) higher than 2,000 mg/kg. Without influence on the production, maturation and death process of immune cells at 20-fold dose of clinical dose (100 mg/kg), silk peptide was evaluated to be a practically non-toxic material.
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