Abstract
Background
Little is known about the natural history of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.
Methods
We conducted a prospective study at a ...quarantine center for coronavirus disease 2019 in Ho Chi Minh City, Vietnam. We enrolled quarantined people with reverse-transcription polymerase chain reaction (RT-PCR)–confirmed SARS-CoV-2 infection, collecting clinical data, travel and contact history, and saliva at enrollment and daily nasopharyngeal/throat swabs (NTSs) for RT-PCR testing. We compared the natural history and transmission potential of asymptomatic and symptomatic individuals.
Results
Between 10 March and 4 April 2020, 14 000 quarantined people were tested for SARS-CoV-2; 49 were positive. Of these, 30 participated in the study: 13 (43%) never had symptoms and 17 (57%) were symptomatic. Seventeen (57%) participants imported cases. Compared with symptomatic individuals, asymptomatic people were less likely to have detectable SARS-CoV-2 in NTS collected at enrollment (8/13 62% vs 17/17 100%; P = .02). SARS-CoV-2 RNA was detected in 20 of 27 (74%) available saliva samples (7 of 11 64% in the asymptomatic group and 13 of 16 81% in the symptomatic group; P = .56). Analysis of RT-PCR positivity probability showed that asymptomatic participants had faster viral clearance than symptomatic participants (P < .001 for difference over the first 19 days). This difference was most pronounced during the first week of follow-up. Two of the asymptomatic individuals appeared to transmit SARS-CoV-2 to 4 contacts.
Conclusions
Asymptomatic SARS-CoV-2 infection is common and can be detected by analysis of saliva or NTSs. The NTS viral loads fall faster in asymptomatic individuals, but these individuals appear able to transmit the virus to others.
Forty-three percent (13/30) of confirmed SARS-CoV-2–infected individuals were asymptomatic, with the virus detected in both saliva and nasopharyngeal/throat swabs. Viral clearance was faster in asymptomatic individuals, but they still appeared able to pass the infection to others.
One of the common problems in strawberry (
Fragaria
×
ananassa
) micropropagation is the vitrification phenomenon (succulent plantlets, brittle stems, yellow leaves, etc.) leading to the reduction ...of plantlets quality and low survival rate in the greenhouse. In this study, the effects of silver nanoparticles (AgNPs) on explant disinfection
,
in vitro growth (shoot multiplication, and root formation), runner formation as well as ethylene accumulation during micropropagation of strawberry were investigated. The results showed that leaf explants treated with 200 mg/L AgNPs solution for 20 min was more effective in explant disinfection and shoot regeneration than using 1 g/L HgCl
2
. In addition, AgNPs stimulated the growth of shoot and plantlet and as well shortened the duration of root formation (4 days) as compared to those in control without AgNPs during micropropagation. Besides, AgNPs reduced the ethylene gas accumulation in the culture’s vessels of shoots (0.66 ppm) and plants (0.06 ppm) compared to controls (1.77 ppm; 0.15 ppm; respectively). Moreover, AgNPs combination with culture period (5; 10 or 15 days) effect root formation stage and acclimatization in the greenhouse. The plantlets that cultured on MS medium supplemethed with 0.5 mg/L AgNPs during 10 days showed higher survival rate (93.33%) after 15 days as well as runner formation per plant (8.00 runners) after 60 days in greenhouse than those in control.
Key message
AgNPs improved explant disinfection and in vitro growth. AgNPs improved runner formation in the greenhouse. AgNPs limited ethylene accumulation during micropropagation.
Mpox was diagnosed in 2 women returning to Vietnam from the United Arab Emirates. The monkeypox viruses belonged to an emerging sublineage, A.2.1, distinct from B.1, which is responsible for the ...ongoing multicountry outbreak. Women could contribute to mpox transmission, and enhanced genomic surveillance is needed to clarify pathogen evolution.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Studies of successive vaccination suggest that immunological memory against past influenza viruses may limit responses to vaccines containing current strains. The impact of memory induced by prior ...infection is rarely considered and is difficult to ascertain, because infections are often subclinical. This study investigated influenza vaccination among adults from the Ha Nam cohort (Vietnam), who were purposefully selected to include 72 with and 28 without documented influenza A(H3N2) infection during the preceding 9 years (Australian New Zealand Clinical Trials Registry 12621000110886). The primary outcome was the effect of prior influenza A(H3N2) infection on hemagglutinin-inhibiting antibody responses induced by a locally available influenza vaccine administered in November 2016. Baseline and postvaccination sera were titrated against 40 influenza A(H3N2) strains spanning 1968-2018. At each time point (baseline, day 14 and day 280), geometric mean antibody titers against 2008-2018 strains were higher among participants with recent infection (34 (29-40), 187 (154-227) and 86 (72-103)) than among participants without recent infection (19 (17-22), 91 (64-130) and 38 (30-49)). On days 14 and 280, mean titer rises against 2014-2018 strains were 6.1-fold (5.0- to 7.4-fold) and 2.6-fold (2.2- to 3.1-fold) for participants with recent infection versus 4.8-fold (3.5- to 6.7-fold) and 1.9-fold (1.5- to 2.3-fold) for those without. One of 72 vaccinees with recent infection versus 4 of 28 without developed symptomatic A(H3N2) infection in the season after vaccination (P = 0.021). The range of A(H3N2) viruses recognized by vaccine-induced antibodies was associated with the prior infection strain. These results suggest that recall of immunological memory induced by prior infection enhances antibody responses to inactivated influenza vaccine and is important to attain protective antibody titers.
This work is to produce multi‐functional active film from polyvinyl (alcohol)/chitosan (PCs) supplemented with Sonneratia ovata leaf extract (SOE) and Piper betel L. oil (PBLO). Our finding showed ...yellowish SOE‐added PCs film with the compact structure possessing lower swelling degree (SD) (22.48%) and higher mechanical strength (5.05 MPa) as compared to the neat PCs (35.43% and 3.18 MPa, respectively). While the co‐supplementation with PBLO at different ratios significantly increased SD between 50.97% and 104.08% due to the more open structure. UV‐barrier, antimicrobial, and antioxidant properties of PCs film were significantly revitalized with co‐supplementation of SOE and PBLO. The PCs/SOE1/PBLO0.5 film presented better force resistance (5.51 MPa) and flexibility (87.12%) than other film formulations with balanced antibacterial and antioxidant properties and hence, it was further applied for preserving fresh‐cut beef for 14 days at 4°C. Changes in visual appearance, drip loss, and pH of fresh‐cut beef during storage period indicated better protective efficacy of PCs/SOE1/PBLO0.5 film as compared to polyethylene (PE), PCs, and SOE‐added PCs materials, suggesting its promisingly potential for food packaging application.
Bioactive and functional biodegradable films are produced from polyvinyl (alcohol)/chitosan incorporated with Sonneratia ovata leaf extract and Piper betel L. leaves essential oil for the purpose of enhancing mechanical behavior, UV‐barrier, antioxidant, and antimicrobial properties of resulting films as well as prolonging the shelf life of fresh‐cut beef.
BackgroundAlthough meningitis is the most severe form of infection caused by Mycobacterium tuberculosis the immunopathogenesis of this disease is poorly understood. We tested the hypothesis that ...polymorphisms in Toll-interleukin 1 receptor domain containing adaptor protein (TIRAP), an adaptor protein that mediates signals from Toll-like receptors activated by mycobacteria, are associated with susceptibility to tuberculosis (TB) MethodsWe used a case-population study design in Vietnam with cord-blood control samples (n=392) and case patients (n=358) who had either pulmonary (n=183) or meningeal (n=175) TB ResultsThe TIRAP single-nucleotide polymorphism (SNP) C558T was associated with increased susceptibility to TB, with a 558T allele frequency of 0.035 in control samples versus 0.074 in case patients (odds ratio OR, 2.25; P<.001). Subgroup analysis revealed that SNP 558T was more strongly associated with susceptibility to meningeal TB (OR, 3.02; P<.001) than to pulmonary TB (OR, 1.55; P=.22). In comparison to the 558CC genotype, the 558TT genotype was associated with decreased whole-blood interleukin-6 production, which suggests that TIRAP influences disease susceptibility by modulating the inflammatory response ConclusionsThese results provide the first evidence of an association of a TIRAP SNP with the risk of any disease and also suggest that the Toll-like receptor pathway influences susceptibility to meningeal and pulmonary TB by different immune mechanisms
Abstract
Background
Pretreatment predictors of death from tuberculous meningitis (TBM) are well established, but whether outcome can be predicted more accurately after the start of treatment by ...updated clinical variables is unknown. Hence, we developed and validated models that dynamically predict mortality using time-updated Glasgow Coma Scale (GCS) and plasma sodium measurements, together with patient baseline characteristics.
Methods
We included 1048 adults from 4 TBM studies conducted in southern Vietnam from 2004 to 2016. We used a landmarking approach to predict death within 120 days after treatment initiation using time-updated data during the first 30 days of treatment. Separate models were built for patients with and without human immunodeficiency virus (HIV) infection. We used the area under the receiver operating characteristic curve (AUC) to evaluate performance of the models at days 10, 20, and 30 of treatment to predict mortality by 60, 90, and 120 days. Our internal validation was corrected for overoptimism using bootstrap. We provide a web-based application that computes mortality risk within 120 days.
Results
Higher GCS indicated better prognosis in all patients. In HIV-infected patients, higher plasma sodium was uniformly associated with good prognosis, whereas in HIV-uninfected patients the association was heterogeneous over time. The bias-corrected AUC of the models ranged from 0.82 to 0.92 and 0.81 to 0.85 in HIV-uninfected and HIV-infected individuals, respectively. The models outperformed the previously published baseline models.
Conclusions
Time-updated GCS and plasma sodium measurements improved predictions based solely on information obtained at diagnosis. Our models may be used in practice to define those with poor prognosis during treatment.
We used time-updated Glasgow Coma Scale and plasma sodium measurements, together with baseline patient characteristics, in a model to dynamically predict death in adults with tuberculous meningitis. Predictions can be made from any time point until day 30 of follow-up.
Spherical-shaped brookite TiO
2
nanoparticles, average size of about ∼ 10 nm, have been prepared by a hydrothermal method at 175°C for 7 h using HCl acid medium at a concentration of 3.0 M and ...amorphous TiO
2
as precursor that was synthesized by the sol–gel method. Under the sunlight equivalent ultraviolet A (UV-A) irradiation, this brookite acts as an efficient photocatalyst for the photodegradation of recalcitrant pharmaceuticals (e.g., cinnamic acid, ibuprofen, and diatrizoic acid). The photocatalytic assay was conducted using a high pharmaceutical load and a low photocatalyst amount, corresponding to a fixed photocatalyst/pharmaceutical mass ratio of 4. The photodegradation of the pharmaceuticals was followed by a combination of ultraviolet/visible (UV/Vis) absorption spectroscopic, total organic carbon (TOC), and electrospray ionisation time-of-flight mass (ESI–TOF–MS) measurements. Scavenger experiments were carried out to confirm the importance of active species including holes and superoxide radicals acting as “door openers” in the photodegradation of pharmaceuticals in terms of aromatic ring opening, thus facilitating complete mineralization.
Brookite TiO2 nanoparticles were synthesized by hydrothermal method and characterized by X-ray powder diffraction (XRD), diffuse reflectance UV–Visible spectroscopy (DRUV), and scanning electron ...microscopy (SEM). The obtained particles were spherical in shape with the diameter of about ~10 nm under the hydrothermal temperature of 175 °C. The photocatalytic performance of brookite was investigated in the photodegradation of dyes (rhodamine B and rose bengal) under UV-A radiation by low-power lamp. The activity of brookite and the photodegradation efficiency of dyes were estimated using a UV–Visible spectrophotometer and a total organic carbon (TOC) analyzer. Compared to anatase and rutile prepared by the similar synthesis procedure, brookite is highly active in terms of decolourization, aromatic ring opening, and mineralization.
Display omitted
•Highly crystalline brookite nanoparticles were synthesized by hydrothermal method.•Brookite is highly active under low power UV–vis irradiation and high dye loading.•Decolourization of dyes is compared to abatement of aromatic ring and mineralization.
Among mitotic kinases, Aurora kinases are the most widely studied, since their expression is restricted to mitosis. They play a key role in chromosome segregation and cell polyploidy. Aurora kinases ...are important therapeutic targets, and several research groups have directed their efforts toward the identification of kinase inhibitors. The aim of this study is to screen and characterize Aurora kinase inhibitors from natural substances extracted from plants that are used in the Vietnamese pharmacopoeia. We have characterized in vitro Derrone, extracted from Erythrina orientalis L. MURR, as a novel Aurora kinase inhibitor. This compound exhibited an ability to inhibit the phosphorylation of histone H3 at ser10 both in kinase assay and at the cellular level. The compound was more effective against Aurora kinase B, with a lower IC50 value as compared to Aurora A. Moreover, it impaired the mitotic spindle checkpoint and led to endoreduplication in cancer cells, a phenomenon caused by an Aurora B inhibitor. Interestingly, using the xCelligence system and real-time cell analysis (RTCA) software, we set up a comparison of cell proliferation profiles between cancer cells treated with Derrone and VX680—a well-known Aurora kinase inhibitor—and we found that these profiles exhibited considerable similarity in cell morphology, growth, and death. Additionally, Derrone significantly inhibited the formation and growth of MCF7 tumor spheroids.
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