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1.
Nature ; 574(7777): 242-245, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31554971

RESUMEN

The Chicxulub bolide impact 66 million years ago drove the near-instantaneous collapse of ocean ecosystems. The devastating loss of diversity at the base of ocean food webs probably triggered cascading extinctions across all trophic levels1-3 and caused severe disruption of the biogeochemical functions of the ocean, and especially disrupted the cycling of carbon between the surface and deep sea4,5. The absence of sufficiently detailed biotic data that span the post-extinction interval has limited our understanding of how ecosystem resilience and biochemical function was restored; estimates6-8 of ecosystem 'recovery' vary from less than 100 years to 10 million years. Here, using a 13-million-year-long nannoplankton time series, we show that post-extinction communities exhibited 1.8 million years of exceptional volatility before a more stable equilibrium-state community emerged that displayed hallmarks of resilience. The transition to this new equilibrium-state community with a broader spectrum of cell sizes coincides with indicators of carbon-cycle restoration and a fully functioning biological pump9. These findings suggest a fundamental link between ecosystem recovery and biogeochemical cycling over timescales that are longer than those suggested by proxies of export production7,8, but far shorter than the return of taxonomic richness6. The fact that species richness remained low as both community stability and biological pump efficiency re-emerged suggests that ecological functions rather than the number of species are more important to community resilience and biochemical functions.


Asunto(s)
Aclimatación , Biodiversidad , Ecosistema , Extinción Biológica , Animales , Isótopos de Carbono/análisis , Cadena Alimentaria , Fósiles , Historia Antigua , Plancton/clasificación , Plancton/aislamiento & purificación
2.
Air Med J ; 40(4): 282-286, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34172240

RESUMEN

Korea rarely has a system to transport patients from abroad. However, single-patient transfers are steadily being performed, and there was an experience of transferring a large number of personnel regardless of whether they were confirmed or not due to coronavirus disease 2019. Recently, a national soccer game was held abroad, and a total of 8 players and staff were infected. A total of 15 people were transported through a charter fully equipped with quarantine equipment by a medical response team with experience in air transport.


Asunto(s)
Ambulancias Aéreas/organización & administración , Atletas , COVID-19/terapia , Cuarentena/métodos , Fútbol , Enfermedad Relacionada con los Viajes , Austria , COVID-19/diagnóstico , COVID-19/transmisión , Humanos , Cuarentena/organización & administración , República de Corea
5.
Opt Express ; 22(15): 18604-11, 2014 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-25089479

RESUMEN

We report on magnetic-field induced transparency (MIT) based on Ramsey electromagnetically induced absorption (EIA) in a paraffin-coated Rb vapor cell. Changing the laser polarization from linear to circular in the presence of a weak residual transverse magnetic field to the laser propagation, the narrow absorption due to the Ramsey EIA transformed into the transparency due to MIT of the 5S1/2 (F = 2)-5P3/2 (F' = 3) transition of 87Rb in the paraffin-coated Rb vapor cell. The spectral widths of the EIA and MIT in the Hanle configuration were measured to be 0.6 mG (425 Hz) and 1.2 mG, respectively. MIT depended on the long preservation time of the ground-state coherent spin states and the transverse magnetic field. From the numerical results, the crossover between the Ramsey EIA and the MIT could be illustrated as the superposition of both signals.

6.
J Microbiol ; 62(8): 639-648, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38916790

RESUMEN

Aconitase-2 (Aco2) is present in the mitochondria, cytosol, and nucleus of fission yeast. To explore its function beyond the well-known role in the mitochondrial tricarboxylic acid (TCA) cycle, we conducted genome-wide profiling using the aco2ΔNLS mutant, which lacks a nuclear localization signal (NLS). The RNA sequencing (RNA-seq) data showed a general downregulation of electron transport chain (ETC) genes in the aco2ΔNLS mutant, except for those in the complex II, leading to a growth defect in respiratory-prone media. Complementation analysis with non-catalytic Aco2 [aco2ΔNLS + aco2(3CS)], where three cysteines were substituted with serine, restored normal growth and typical ETC gene expression. This suggests that Aco2's catalytic activity is not essential for its role in ETC gene regulation. Our mRNA decay assay indicated that the decrease in ETC gene expression was due to transcriptional regulation rather than changes in mRNA stability. Additionally, we investigated the Php complex's role in ETC gene regulation and found that ETC genes, except those within complex II, were downregulated in php3Δ and php5Δ strains, similar to the aco2ΔNLS mutant. These findings highlight a novel role for nuclear aconitase in ETC gene regulation and suggest a potential connection between the Php complex and Aco2.


Asunto(s)
Aconitato Hidratasa , Regulación Fúngica de la Expresión Génica , Mitocondrias , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Aconitato Hidratasa/genética , Aconitato Hidratasa/metabolismo , Núcleo Celular/metabolismo , Núcleo Celular/genética , Ciclo del Ácido Cítrico/genética , Transporte de Electrón/genética , Mitocondrias/genética , Mitocondrias/metabolismo , Mutación , Señales de Localización Nuclear/genética , Estabilidad del ARN , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Schizosaccharomyces/enzimología , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Transcripción Genética
7.
J Korean Med Sci ; 28(2): 336-9, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23400265

RESUMEN

Although renal calcium crystal deposits (nephrocalcinosis) may occur in acute phosphate poisoning as well as type 1 renal tubular acidosis (RTA), hyperphosphatemic hypocalcemia is common in the former while normocalcemic hypokalemia is typical in the latter. Here, as a unique coexistence of these two seperated clinical entities, we report a 30-yr-old woman presenting with carpal spasm related to hypocalcemia (ionized calcium of 1.90 mM/L) due to acute phosphate poisoning after oral sodium phosphate bowel preparation, which resolved rapidly after calcium gluconate intravenously. Subsequently, type 1 RTA due to Sjögren's syndrome was unveiled by sustained hypokalemia (3.3 to 3.4 mEq/L), persistent alkaline urine pH (> 6.0) despite metabolic acidosis, and medullary nephrocalcinosis. Through this case report, the differential points of nephrocalcinosis and electrolyte imbalances between them are discussed, and focused more on diagnostic tests and managements of type 1 RTA.


Asunto(s)
Acidosis Tubular Renal/diagnóstico , Hipocalcemia/inducido químicamente , Nefrocalcinosis/diagnóstico , Fosfatos/efectos adversos , Síndrome de Sjögren/diagnóstico , Acidosis Tubular Renal/etiología , Enfermedad Aguda , Adulto , Anticuerpos Antinucleares/sangre , Gluconato de Calcio/uso terapéutico , Enfermedad Crónica , Femenino , Humanos , Concentración de Iones de Hidrógeno , Hipocalcemia/complicaciones , Hipocalcemia/tratamiento farmacológico , Nefrocalcinosis/complicaciones , Nefrocalcinosis/diagnóstico por imagen , Glándula Parótida/diagnóstico por imagen , Cintigrafía , Glándulas Salivales/diagnóstico por imagen , Síndrome de Sjögren/complicaciones , Síndrome de Sjögren/metabolismo , Glándula Submandibular/diagnóstico por imagen , Ultrasonografía
8.
Mar Pollut Bull ; 189: 114764, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36870135

RESUMEN

To assess the progression of ocean acidification in the South Yellow Sea (SYS), the aragonite saturation state (Ωarag) was determined from dissolved inorganic carbon (DIC) and total alkalinity (TA) in the surface and bottom waters of the SYS in spring and autumn. The Ωarag exhibited large spatiotemporal variations in the SYS; DIC was a major factor controlling the Ωarag variations, whereas temperature, salinity, and TA were minor factors. Surface DIC concentrations were mainly influenced by the lateral transport of the DIC-enriched Yellow River waters and DIC-depleted East China Sea Surface Water; bottom DIC concentrations were affected by aerobic remineralization in spring and autumn. Ocean acidification is now seriously progressing in the SYS, particularly in the Yellow Sea Bottom Cold Water (YSBCW) where the mean value of Ωarag substantially decreased from 1.55 in spring to 1.22 in autumn. All Ωarag values measured in the YSBCW in autumn were lower than the critical threshold value of 1.5 necessary for the survival of calcareous organisms.


Asunto(s)
Carbonato de Calcio , Agua de Mar , Carbonato de Calcio/análisis , Concentración de Iones de Hidrógeno , Océanos y Mares , China , Agua
9.
J Clin Med ; 12(18)2023 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-37762810

RESUMEN

As the association between obesity and bone health remains controversial in children and adolescents, we investigate the effects of obesity parameters on bone mineral density (BMD) in 2060 Korean adolescents who participated in the 2008-2011 Korea National Health and Nutrition Examination Survey (KNHANES). Multiple regression analysis and analysis of covariance (ANCOVA) were conducted to examine both the linear and non-linear associations between total-body-less-head (TBLH) BMD and four obesity parameters: body mass index, waist circumference, waist-to-height ratio, and total-body fat mass (FM). In a multiple linear regression analysis adjusted for age, menarcheal status (in females only), and total-body lean mass, there was no significant linear association between obesity parameters and TBLH BMD, except for total-body FM in males. However, upon adding a second-order polynomial term for each obesity parameter, a significant quadratic relationship between all obesity parameters and TBLH BMD was observed, with the corresponding quadratic term being negative. The results of ANCOVA also revealed an inverted U-shaped relationship between each obesity parameter and TBLH BMD. Our findings suggest the existence of an optimal range of obesity parameters for developing or maintaining optimal bone health in Korean Adolescents. Deviation from this range, in either direction (being underweight or having obesity), may compromise bone health.

10.
Ann Surg Treat Res ; 104(1): 34-42, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36685774

RESUMEN

Purpose: This study aims to investigate the feasibility of Zenith Fenestrated AAA Endovascular Graft (Z-FEN, Cook Medical) from a single Korean institution database by evaluating the vascular anatomy of Korean abdominal aortic aneurysm (AAA) patients with hostile aortic neck. Methods: This is a retrospective study on patients with AAA who underwent endovascular aortic repair (EVAR) and open surgery repair between January 2012 and December 2021 (n = 211). The anatomic characteristics of the aortic neck were evaluated using 3-dimensional reconstructed computed tomographic scans. For the juxtarenal AAA patients (n = 39), feasibility of fenestrated stent graft was evaluated under the protocol of fenestrated EVAR. For those who were not suitable for the application of Z-FEN, the reasons for unsuitability were analyzed. Results: Among 211 AAA patients, 108 patients (51.2%) had complex aortic neck, and 39 (18.5%) had insufficient aortic neck length (<15 mm) for conventional EVAR. Of the 39 patients with juxtarenal AAAs, 13 (33.3%) were determined feasible for Z-FEN. Twenty-six patients (66.7%) were noncandidate for Z-FEN due to severe neck angulation, short aortic neck length, inadequate iliac artery anatomy, large aortic neck diameter, and severe calcification and thrombosis. Proximal aortic neck length of the non-feasible group was significantly shorter than that of the feasible group (P = 0.002). Conclusion: Z-FEN was applicable to 33.3% of the juxtarenal AAA patients. As recent studies confirm, the effectiveness and safety of fenestrated EVAR, Z-FEN can be an option for AAA patients with short aortic neck.

11.
Nat Commun ; 14(1): 5262, 2023 08 29.
Artículo en Inglés | MEDLINE | ID: mdl-37644026

RESUMEN

Measuring, recording and analyzing spectral information of materials as its unique finger print using a ubiquitous smartphone has been desired by scientists and consumers. We demonstrated it as drug classification by chemical components with smartphone Raman spectrometer. The Raman spectrometer is based on the CMOS image sensor of the smartphone with a periodic array of band pass filters, capturing 2D Raman spectral intensity map, newly defined as spectral barcode in this work. Here we show 11 major components of drugs are classified with high accuracy, 99.0%, with the aid of convolutional neural network (CNN). The beneficial of spectral barcodes is that even brand name of drug is distinguishable and major component of unknown drugs can be identified. Combining spectral barcode with information obtained by red, green and blue (RGB) imaging system or applying image recognition techniques, this inherent property based labeling system will facilitate fundamental research and business opportunities.


Asunto(s)
Espectrometría Raman , Comercio , Citoplasma , Dedos , Teléfono Inteligente , Espectrometría Raman/instrumentación
12.
Genes (Basel) ; 14(12)2023 11 30.
Artículo en Inglés | MEDLINE | ID: mdl-38136985

RESUMEN

Myopia is a substantial global public health concern primarily linked to the elongation of the axial length of the eyeball. While numerous animal models have been employed to investigate myopia, the specific contributions of genetic factors and the intricate signaling pathways involved remain incompletely understood. In this study, we conducted RNA-seq analysis to explore genes and pathways in two distinct myopia-inducing mouse models: form-deprivation myopia (FDM) and lens-induced myopia (LIM). Comparative analysis with a control group revealed significant differential expression of 2362 genes in FDM and 503 genes in LIM. Gene Set Enrichment Analysis (GSEA) identified a common immune-associated pathway between LIM and FDM, with LIM exhibiting more extensive interactions. Notably, downregulation was observed in OxPhos complex III of FDM and complex IV of LIM. Subunit A of complex I was downregulated in LIM but upregulated in FDM. Additionally, complex V was upregulated in LIM but downregulated in FDM. These findings suggest a connection between alterations in energy metabolism and immune cell activation, shedding light on a novel avenue for understanding myopia's pathophysiology. Our research underscores the necessity for a comprehensive approach to comprehending myopia development, which integrates insights from energy metabolism, oxidative stress, and immune response pathways.


Asunto(s)
Miopía , Animales , Ratones , Miopía/genética , Ojo , Modelos Animales de Enfermedad , Metabolismo Energético/genética , ARN/metabolismo
13.
Am J Kidney Dis ; 59(4): 577-81, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22265393

RESUMEN

Underlying causes of metabolic alkalosis may be evident from history, evaluation of effective circulatory volume, and measurement of urine chloride concentration. However, identification of causes may be difficult for certain conditions associated with clandestine behaviors, such as surreptitious vomiting, use of drugs or herbal supplements with mineralocorticoid activity, abuse of laxatives or diuretics, and long-term use of alkalis. In these circumstances, clinicians often are bewildered by unexplained metabolic alkalosis from an incomplete history or persistent deception by the patient, leading to misdiagnosis and poor outcome. We present a case of severe metabolic alkalosis and hypokalemia with a borderline urine chloride concentration in an alcoholic patient treated with a thiazide. The cause of the patient's metabolic alkalosis eventually was linked to surreptitious ingestion of baking soda. This case highlights the necessity of a high index of suspicion for the diverse clandestine behaviors that can cause metabolic alkalosis and the usefulness of urine pH and anion gap in its differential diagnosis.


Asunto(s)
Equilibrio Ácido-Base , Alcalosis/etiología , Hipopotasemia/etiología , Bicarbonato de Sodio/efectos adversos , Orina , Anciano , Alcoholismo/tratamiento farmacológico , Alcoholismo/metabolismo , Alcalosis/diagnóstico , Alcalosis/epidemiología , Cloruros/orina , Comorbilidad , Ingestión de Alimentos , Humanos , Concentración de Iones de Hidrógeno , Hipopotasemia/diagnóstico , Hipopotasemia/epidemiología , Masculino , Bicarbonato de Sodio/administración & dosificación , Tiazidas/uso terapéutico
14.
Opt Express ; 20(9): 9485-92, 2012 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-22535039

RESUMEN

The effect of wall-induced Ramsey interference on the electromagnetically induced absorption (EIA) in an anti-relaxation coated vapor cell is studied in a four-level closed N-type atomic system. We show that the atomic coherence spontaneously transferred from the excited states to the ground states may interfere via the Ramsey sequence of the moving atoms with decoherence-free wall collisions. The spectral narrowing of the EIA resonance lineshape is induced by the Ramsey effect because of the long lifetime of the spontaneously transferred atomic coherence between the ground states. This calculated Ramsey EIA spectrum is in good agreement with the narrow EIA spectrum obtained experimentally in the anti-relaxation coated vapor cell.


Asunto(s)
Campos Electromagnéticos , Modelos Teóricos , Dispersión de Radiación , Absorción , Simulación por Computador
15.
J Korean Med Sci ; 27(10): 1265-8, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23091328

RESUMEN

Ultrasound-guided cannulation of a large-bore catheter into the internal jugular vein was performed to provide temporary hemodialysis vascular access for uremia in a 65-yr-old woman with acute renal failure and sepsis superimposed on chronic renal failure. Despite the absence of any clinical evidence such as bleeding or hematoma during the procedure, a chest x-ray and computed tomographic angiogram of the neck showed that the catheter had inadvertently been inserted into the subclavian artery. Without immediately removing the catheter and applying manual external compression, the arterial misplacement of the hemodialysis catheter was successfully managed by open surgical repair. The present case suggests that attention needs to be paid to preventing iatrogenic arterial cannulation during central vein catheterization with a large-bore catheter and to the management of its potentially devastating complications, since central vein catheterization is frequently performed by nephrologists as a common clinical procedure to provide temporary hemodialysis vascular access.


Asunto(s)
Cateterismo Venoso Central/efectos adversos , Fallo Renal Crónico/diagnóstico , Errores Médicos/prevención & control , Arteria Subclavia/diagnóstico por imagen , Acidosis/complicaciones , Enfermedad Aguda , Anciano , Femenino , Hemorragia/etiología , Humanos , Oliguria/complicaciones , Diálisis Renal , Sepsis/etiología , Arteria Subclavia/lesiones , Arteria Subclavia/cirugía , Tomografía Computarizada por Rayos X , Uremia/etiología
16.
Opt Express ; 19(1): 168-74, 2011 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-21263554

RESUMEN

We report on electromagnetically induced absorption (EIA) with sub-kHz spectral width in a paraffin-coated Rb vapor cell in the Hanle configuration of the 5S(1/2)(F=2)-5P(3/2)(F'=3) transition of 87Rb atoms. Using a linearly polarized laser, the spectral width of the Hanle EIA spectrum was measured to be 0.55 mG (390 Hz). The narrow spectral width was due to the maintaining of atomic coherence between ground states while atoms collided with the anti-relaxation coated wall of the Rb vapor cell. Under a weak transverse residual magnetic field, the angle between the transverse residual magnetic field and the direction of linear polarization affected the magnitude of the narrow Hanle EIA spectrum. This is because of the change of atomic magnetic momentum due to the weak transverse residual magnetic field around the zero value of the longitudinal magnetic field.

17.
Medicine (Baltimore) ; 100(47): e27948, 2021 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-34964775

RESUMEN

ABSTRACT: South Korean studies on coronavirus disease-2019 (COVID-19) treatment have described the use of community treatment centers (CTCs), which combine elements of the home and hospital, to isolate and treat mild COVID-19 patients. While the number of South Koreans diagnosed with COVID-19 cases has varied greatly by season, the number of confirmed cases in foreign nationals has shown no seasonality, with an average of around 25 to 30 per day. For foreign patients, accommodation arrangements and travel routes may be difficult; they may also have difficulty accessing medical care, so require careful management.We discuss our experience in operating and managing a CTC for foreign COVID-19 patients arriving in South Korea with mild symptoms. We also propose guidelines for efficient use of resources with respect to treating these patients in CTCs.We present the clinical findings of patients treated at the CTC between 7 October and 22 November 2020, and make some recommendations. We quarantined and treated foreign patients with mild symptoms of COVID-19 at the Ansan CTC. Discharge is determined based on clinical symptoms rather than polymerase chain reaction results. Medical and administrative staff use building A, while building B is used for isolating patients. Medical rounds are in the form of twice-daily video calls. Three kinds of foods with medication are served according to the patient's country of origin.In total, 315 patients were admitted to the Ansan CTC between 7 October and 22 November 2020; 145 of them were discharged from the CTC and 26 were transferred to other hospitals.To utilize medical resources efficiently during the pandemic, it is desirable to reserve CTCs exclusively for foreign patients.


Asunto(s)
COVID-19 , Centros Comunitarios de Salud/organización & administración , Pandemias/prevención & control , Aislamiento de Pacientes/métodos , Transferencia de Pacientes , Telemedicina/métodos , Humanos , Cuarentena/métodos , República de Corea , SARS-CoV-2
18.
Eur J Trauma Emerg Surg ; 47(5): 1437-1449, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30798345

RESUMEN

PURPOSE: This study aimed to measure the preventive effect of seat belt on traumatic brain injury (TBI) and to compare the effect according to the crash severities and collision directions. METHODS: Korea In-Depth Accident Study (KIDAS) has collected vehicle and demographic data on injured occupants involved in motor vehicle collisions (MVCs) who visited three emergency medical centers for calendar years 2011-2016. Primary and secondary end points were TBI (abbreviated injury score 2+) and in-hospital mortality. Crush extent (CE) was classified into 1-2, 3-4, 5-6, and 7-9 according to the crash severity. We calculated adjusted odds ratios (ORs) of seat belts and CE for study outcomes and developed an interaction model in each collision direction using multivariate logistic regression analysis. RESULTS: Of the 2,245 occupants who were injured in MVCs, 295 (13.1%) occupants sustained TBI. In univariate analysis, old age, unbelted status, lateral collision, and higher CE were factors associated with TBI in MVCs. Occupants with belted status was less likely to have TBI and in-hospital mortality compared with those with unbelted status [AORs (95% CI) 0.48 (0.37-0.62) and 0.49 (0.30-0.81), respectively]. In interaction analysis, preventive effects of seat belts on TBI from MVCs were retained within CE 5-6 in frontal MVCs and within CE 1-2 in near side lateral MVCs, and those of seat belts on in-hospital mortality were reserved within CE 3-4 in frontal and rollover MVCs. CONCLUSIONS: The preventive effects of seat belts on TBI and in-hospital mortality are preserved within a limited crash severity in each collision direction.


Asunto(s)
Lesiones Traumáticas del Encéfalo , Heridas y Lesiones , Accidentes de Tránsito , Lesiones Traumáticas del Encéfalo/prevención & control , Humanos , Vehículos a Motor , Oportunidad Relativa , Cinturones de Seguridad
19.
Am J Nurs ; 120(8): 64-65, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32732485

RESUMEN

Updated several times a week with posts by a wide variety of authors, AJN's blog Off the Charts allows us to provide more timely-and often more personal-perspectives on professional, policy, and clinical issues. Best of the Blog is a regular column to draw the attention of AJN readers to posts we think deserve a wider audience. To read more, please visit: www.ajnoffthecharts.com.


Asunto(s)
Personal de Enfermería/psicología , Betacoronavirus/aislamiento & purificación , COVID-19 , Infecciones por Coronavirus/enfermería , Infecciones por Coronavirus/virología , Miedo , Humanos , Pandemias , Seguridad del Paciente , Neumonía Viral/enfermería , Neumonía Viral/virología , SARS-CoV-2 , Estados Unidos
20.
JAMA Intern Med ; 180(11): 1447-1452, 2020 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-32780793

RESUMEN

IMPORTANCE: There is limited information about the clinical course and viral load in asymptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). OBJECTIVE: To quantitatively describe SARS-CoV-2 molecular viral shedding in asymptomatic and symptomatic patients. DESIGN, SETTING, AND PARTICIPANTS: A retrospective evaluation was conducted for a cohort of 303 symptomatic and asymptomatic patients with SARS-CoV-2 infection between March 6 and March 26, 2020. Participants were isolated in a community treatment center in Cheonan, Republic of Korea. MAIN OUTCOMES AND MEASURES: Epidemiologic, demographic, and laboratory data were collected and analyzed. Attending health care personnel carefully identified patients' symptoms during isolation. The decision to release an individual from isolation was based on the results of reverse transcription-polymerase chain reaction (RT-PCR) assay from upper respiratory tract specimens (nasopharynx and oropharynx swab) and lower respiratory tract specimens (sputum) for SARS-CoV-2. This testing was performed on days 8, 9, 15, and 16 of isolation. On days 10, 17, 18, and 19, RT-PCR assays from the upper or lower respiratory tract were performed at physician discretion. Cycle threshold (Ct) values in RT-PCR for SARS-CoV-2 detection were determined in both asymptomatic and symptomatic patients. RESULTS: Of the 303 patients with SARS-CoV-2 infection, the median (interquartile range) age was 25 (22-36) years, and 201 (66.3%) were women. Only 12 (3.9%) patients had comorbidities (10 had hypertension, 1 had cancer, and 1 had asthma). Among the 303 patients with SARS-CoV-2 infection, 193 (63.7%) were symptomatic at the time of isolation. Of the 110 (36.3%) asymptomatic patients, 21 (19.1%) developed symptoms during isolation. The median (interquartile range) interval of time from detection of SARS-CoV-2 to symptom onset in presymptomatic patients was 15 (13-20) days. The proportions of participants with a negative conversion at day 14 and day 21 from diagnosis were 33.7% and 75.2%, respectively, in asymptomatic patients and 29.6% and 69.9%, respectively, in symptomatic patients (including presymptomatic patients). The median (SE) time from diagnosis to the first negative conversion was 17 (1.07) days for asymptomatic patients and 19.5 (0.63) days for symptomatic (including presymptomatic) patients (P = .07). The Ct values for the envelope (env) gene from lower respiratory tract specimens showed that viral loads in asymptomatic patients from diagnosis to discharge tended to decrease more slowly in the time interaction trend than those in symptomatic (including presymptomatic) patients (ß = -0.065 [SE, 0.023]; P = .005). CONCLUSIONS AND RELEVANCE: In this cohort study of symptomatic and asymptomatic patients with SARS-CoV-2 infection who were isolated in a community treatment center in Cheonan, Republic of Korea, the Ct values in asymptomatic patients were similar to those in symptomatic patients. Isolation of asymptomatic patients may be necessary to control the spread of SARS-CoV-2.


Asunto(s)
Infecciones Asintomáticas , Hospitales de Aislamiento , Aislamiento de Pacientes/métodos , SARS-CoV-2 , Carga Viral/métodos , Esparcimiento de Virus , Adulto , Infecciones Asintomáticas/epidemiología , Infecciones Asintomáticas/terapia , COVID-19/diagnóstico , COVID-19/fisiopatología , Prueba de COVID-19/métodos , Prueba de COVID-19/estadística & datos numéricos , Monitoreo Epidemiológico , Femenino , Hospitales de Aislamiento/métodos , Hospitales de Aislamiento/estadística & datos numéricos , Humanos , Masculino , Salud Pública/estadística & datos numéricos , República de Corea/epidemiología , Estudios Retrospectivos , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/fisiología , Evaluación de Síntomas/métodos , Evaluación de Síntomas/estadística & datos numéricos
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