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Objective: To analyze the epidemiological characteristics and influencing factors of COVID-19 confirmed cases with viral nucleic acid re-positive in anal and/or throat swabs after discharge during the domestic imported epidemic stage in Guangdong Province in early 2020. Methods: The COVID-19 confirmed cases with the onset time before March 1, 2020 in Guangdong Province were collected to analyze the demographic data, epidemiological characteristics, and specimen collection and testing data after discharge. Logistic regression model was used for influencing factors analysis of re-positive cases. Results: A total of 1 286 COVID-19 confirmed cases were included, the M(Q1,Q3) of age was 44(32,58)years, 617 cases were male, 224 cases were re-positive in anal and/or throat swabs with the re-positive rate 17.42%. The M(Q1,Q3) of age of re-positive cases was 35(23, 50) years, which was younger than that of re-negative cases age was those 46(33, 59) years (P<0.001). With the increase of age, re-positive rate decreased (χ2trend=52.73, P<0.001). 85.27% (191/224) of re-positive cases were found in 14 d after discharge, the duration time of re-positive status was 13(7, 24) d, and 81.69% (183/224) of re-positive cases were re-tested negative in 28 d after re-positive date. No fever and other symptoms had been observed among re-positive cases during the whole follow-up. No secondary infectious cases had been found among close contacts after 14 d of centralized isolation and sampling screening. Univariate logistic regression model analysis revealed that the influencing factors of the re-positive cases included age, occupation, clusters, clinical types, and admission time. Multivariate logistic regression model analysis revealed that age was an independent risk factor. Conclusions: SARS-CoV-2 viral nucleic acid re-positive is found in COVID-19 confirmed cases after discharge in Guangdong Province. Most re-positive cases are confirmed among 14 d after discharge and re-test to negative among 28 d after re-positive date. Age is an risk factor for re-positive cases after discharge.
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Humanos , Masculino , COVID-19 , China/epidemiología , Epidemias , Ácidos Nucleicos , SARS-CoV-2RESUMEN
BackgroundThe Delta variant of SARS-CoV-2 has become predominant globally. We evaluated the transmission dynamics and epidemiological characteristics of the Delta variant in an outbreak in southern China. MethodsData on confirmed cases and their close contacts were retrospectively collected from the outbreak that occurred in Guangdong, China in May-June 2021. Key epidemiological parameters, temporal trend of viral loads and secondary attack rates were estimated and compared between the Delta variant and the wild-type SARS-CoV-2 virus. We also evaluated the association of vaccination with viral load and transmission. ResultsWe identified 167 patients infected with the Delta variant in the Guangdong outbreak. The mean estimates of the latent period and the incubation period were 4.0 days and 5.8 days, respectively. A relatively higher viral load was observed in Delta cases than in wild-type infections. The secondary attack rate among close contacts of Delta cases was 1.4%, and 73.9% (95% confidence interval: 67.2%, 81.3%) of the transmissions occurred before onset. Index cases without vaccination (OR: 2.84, 95% confidence interval: 1.19, 8.45) or with one dose of vaccination (OR: 6.02, 95% confidence interval: 2.45, 18.16) were more likely to transmit infection to their contacts than those who had received 2 doses of vaccination. DiscussionPatients infected with the Delta variant had more rapid symptom onset. The shorter and time-varying serial interval should be accounted in estimation of reproductive numbers. The higher viral load and higher risk of pre-symptomatic transmission indicated the challenges in control of infections with the Delta variant.
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We report the first local transmission of the SARS-CoV-2 Delta variant in mainland China. All 167 infections could be traced back to the first index case. Daily sequential PCR testing of the quarantined subjects indicated that the viral loads of Delta infections, when they first become PCR+, were on average [~]1000 times greater compared to A/B lineage infections during initial epidemic wave in China in early 2020, suggesting potentially faster viral replication and greater infectiousness of Delta during early infection. We performed high-quality sequencing on samples from 126 individuals. Reliable epidemiological data meant that, for 111 transmission events, the donor and recipient cases were known. The estimated transmission bottleneck size was 1-3 virions with most minor intra-host single nucleotide variants (iSNVs) failing to transmit to the recipients. However, transmission heterogeneity of SARS-CoV-2 was also observed. The transmission of minor iSNVs resulted in at least 4 of the 30 substitutions identified in the outbreak, highlighting the contribution of intra-host variants to population level viral diversity during rapid spread. Disease control activities, such as the frequency of population testing, quarantine during pre-symptomatic infection, and level of virus genomic surveillance should be adjusted in order to account for the increasing prevalence of the Delta variant worldwide.
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Bat coronavirus (CoV) RaTG13 shares the highest genome sequence identity with SARS-CoV-2 among all known coronaviruses, and also uses human angiotensin converting enzyme 2 (hACE2) for virus entry. Thus, SARS-CoV-2 is thought to have originated from bat. However, whether SARS-CoV-2 emerged from bats directly or through an intermediate host remains elusive. Here, we found that Rhinolophus affinis bat ACE2 (RaACE2) is an entry receptor for both SARS-CoV-2 and RaTG13, although RaACE2 binding to the receptor binding domain (RBD) of SARS-CoV-2 is markedly weaker than that of hACE2. We further evaluated the receptor activities of ACE2s from additional 16 diverse animal species for RaTG13, SARS-CoV, and SARS-CoV-2 in terms of S protein binding, membrane fusion, and pseudovirus entry. We found that the RaTG13 spike (S) protein is significantly less fusogenic than SARS-CoV and SARS-CoV-2, and seven out of sixteen different ACE2s function as entry receptors for all three viruses, indicating that all three viruses might have broad host rages. Of note, RaTG13 S pseudovirions can use mouse, but not pangolin ACE2, for virus entry, whereas SARS-CoV-2 S pseudovirions can use pangolin, but limited for mouse, ACE2s enter cells. Mutagenesis analysis revealed that residues 484 and 498 in RaTG13 and SARS-CoV-2 S proteins play critical roles in recognition of mouse and human ACE2. Finally, two polymorphous Rhinolophous sinicus bat ACE2s showed different susceptibilities to virus entry by RaTG13 and SARS-CoV-2 S pseudovirions, suggesting possible coevolution. Our results offer better understanding of the mechanism of coronavirus entry, host range, and virus-host coevolution.
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BackgroundOn December 31, 2019, an outbreak of COVID-19 in humans was reported in Wuhan, and then spread fast to other provinces, China. We analyzed data from field investigations and genetic sequencing to describe the evidence and characteristics of human-to-human transmission in Guangdong Province. MethodsA confirmed COVID-19 case was defined if a suspected case was verified with positive of SARS-CoV-2 in throat swabs, nasal swabs, bronchoalveolar lavage fluid (BALF), or endotracheal aspirates by real-time reverse transcriptase polymerase chain reaction assay (RT-PCR) or genetic sequencing. Field investigations were conducted for each confirmed case. Clinical and demographic data of confirmed cases were collected from medical records. Exposure and travel history were obtained by interview. ResultsA total of 1,151 confirmed cases were identified as of February 10, 2020 in Guangdong Province, China. Of them, 697 (60.1%) cases were from 234 cluster infections. Two hundred and fourteen (18.6%) were secondary cases, in which 144 cases were from family cluster infections. With the epidemic continuing, although familial cluster events were dominated, community cluster events increased with a nosocomial event. The whole genomes within the same family cluster infections were identical, and presented a few unique single nucleotide variants (SNVs) compared with SARS-CoV-2 identified on December 2019 in Wuhan. ConclusionsWe observed evident human-to-human transmissions of SARS-CoV-2 in Guangdong, China. Although most of them were from family cluster infections, community and nosocomial infections were increasing. Our findings indicate that human-to-human transmission risks are transferring from family to community in Guangdong Province.
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Objective To analyze the clinical courses and outcomes of COVID-19 cases and the influencing factors in Guangdong province and provide basis for the formulation or adjustment of medical care and epidemic control strategy for COVID-19. Methods We collected demographic data, medical histories, clinical courses and outcomes of 1 350 COVID-19 patients reported in Guangdong as of 4 March 2020 via epidemiological investigation and process tracking. Disease severity and clinical course characteristics of the patients and influencing factors of severe illness were analyzed in our study. Results Among 1 350 cases of COVID-19 cases in Guangdong, 72 (5.3%) and 1049 (77.7%) were mild and ordinary cases, 164 (12.1%) were severe cases, 58 (4.3%) were critical cases and 7 (0.5%) were fatal. The median duration of illness were 23 days ( P 25 - P 75 : 18-31 days) and the median length of hospitalization were 20 days ( P 25 - P 75 : 15-27 days). For severe cases, the median time of showing severe manifestations was on the 12th day after onset ( P 25 - P 75 : 9th to 15th days), and the median time of severe manifestation lasted for 8 days P 25 - P 75 : 4-14 days). Among 1 066 discharged/fetal cases, 36.4% (36/99) and 1.0% (1/99) of the mild cases developed to ordinary cases and severe cases respectively after admission; and 5.2% (50/968) and 0.6% (6/968) of the ordinary cases developed to severe cases, and critical cases respectively after admission. In severe cases, 11.4% developed to critical cases (10/88). The influencing factors for severe illness or worse included male (a HR =1.87, 95% CI : 1.43-2.46), older age (a HR =1.67, 95% CI : 1.51-1.85), seeking medical care on day 2-3 after onset (a HR =1.73, 95% CI : 1.20-2.50) pre-existing diabetes (a HR =1.75, 95% CI : 1.12-2.73) and hypertension (a HR =1.49, 95% CI : 1.06-2.09). Conclusions The course of illness and length of hospitalization of COVID-19 cases were generally long and associated with severity of disease clinical outcomes. The severe cases were mainly occurred in populations at high risk. In the epidemic period, classified management of COVID-19 cases should be promoted according to needs for control and prevention of isolation and treatment for the purpose of rational allocation of medical resources.
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Interactive image segmentation is a challenging task and receives increasing attention recently; however, two major drawbacks exist in interactive segmentation approaches. First, the segmentation performance of region of interest (ROI)-based methods is sensitive to the initial ROI: different ROIs may produce results with great difference. Second, most seed-based methods need intense interactions, and are not applicable in many cases. In this paper, we generalize the neutro-connectedness (NC) to be independent of top-down priors of objects and to model image topology with indeterminacy measurement on image regions, propose a novel method for determining object and background regions, which is applied to exclude isolated background regions and enforce label consistency, and put forward a hybrid interactive segmentation method, NC Cut (NC-Cut), which can overcome the above two problems by utilizing both pixelwise appearance information and region-based NC properties. We evaluate the proposed NC-Cut by employing two image data sets (265 images), and demonstrate that the proposed approach outperforms the state-of-the-art interactive image segmentation methods (Grabcut, MILCut, One-Cut, MGCmaxsum, and pPBC).
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Objective To sum up the characteristics of hemorrhagic fever with renal syndrome(HFRS)and acute pancreatitis,to improve the understanding of the cases of atypical HFRS,reduce the misdiagnosis rate and improve the cure rate.Methods 3 cases of HFRS complicated with acute pancreatitis in our hospital from 2011 to 2015 were retrospectively analyzed.Results 3 cases were middle -aged men,with an average age of 46.6,of which two cases occurred in Huangling county in the city,the remaining 1 case occurred in Yichuan county of the city. Occupation was the railway workers,drivers,farmers.Respectively occurred in February,July,December.3 cases of blood routine,urine routine,blood coagulation performance were consistent performance for RBC,WBC,PLT decrease;hematuria,proteinuria;3 cases of plasma amylase were higher than that of more than 3 times the normal value,the serum lipase was higher than the more than 3 times the normal value;hemorrhagic fever antibodies were positive;treatment of 2 cases with hemodialysis treatment,1 case underwent intestinal dialysis treatment,successful treatment of all.Conclusion HFRS with acute pancreatitis patients were less,easy to be misdiagnosed or ignored,easy illness of incur loss through delay and once with acute pancreatitis will add to the original condition,treatment more difficult tend to have higher mortality rate.It should be according to the clinical manifestations,early blood and urine amylase, abdominal B ultrasound and CT examinations of the abdomen as soon as possible,to improve the accuracy of diagnosis, take appropriate treatment measures,especially blood dialysis treatment,can reduce the mortality rate.
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Tyrosinase is a key enzyme related to skin pigmentation disorders of elderly people, while self-aggregation of the amyloid-beta peptide, Abeta42, has been considered as a key event in the pathogenesis of Alzheimer's disease (AD). The present study was undertaken to investigate the inhibitory effects of 20 samples from Rhodiola species on tyrosinase and Abeta42 aggregation, and to isolate their corresponding bioactive components. The results demonstrated that the oligomeric proanthocyanidins (OPCs) commonly found in Rhodiola species were the major bioactive components corresponding to their anti-tyrosinase and anti-Abeta42 aggregation bioactivities. Salidroside, a representative compound of Rhodiola plants, proved not to be active in the present studies.
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Objective To compare influences of enteral nutrition (EN) and parenteral nutrition (PN) on the inflammatory factors and immune functions in patients with systemic inflammatory response syndrome. Methods Totally 85 patients who were treated in the First Hospital of Shanxi Medical University, Shanxi Province People's Hospital, and Taiyuan Central Hospital from April, 2006 to April, 2010 were enrolled in this study and divided into EN group (n = 49) and PN group (n = 36) according to nutrition support modes. The changes of inflammatory factors and immune functions after nutritional supports were recorded and compared between these two groups. Results The weight, arm circumference, skin fold thickness of brachial triceps, total protein, and serum albumin were significantly improved on the 7th and 14th day after nutrition supports in both two groups compared with the baseline levels (all P ＜ 0.05). On the 14th day after nutritional support, the levels of total protein and serum albumin were significantly higher in EN group than in PN group. On the 7th and 14th day, the levels of tumor necrosis factor-α, Interleukin (IL)-8, and IL-1β in EN group were significantly lower than those in PN group and baseline levels (all P ＜ 0. 05). The blood CD4/CD8 and IgG in EN group were significantly increased compared with the baseline levels and those in PN group (both P ＜0. 05). Conclusions Both PN and EN can effectively improve the nutritional status of patients with SIRS. EN has superior effectiveness in EN group than in PN group in terms of improving nutritional status, ameliorating immune function, and reducing the release of inflammatory factors.
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Objective To propose a novel computer-aided segment algorithm, and retrospectively investigate its effect on radiologist's sensitivity and specificity for discriminating malignant masses from benign masses basing on ultrasound images. Methods Four hundred and sixty-six images of 100 masses obtained by conventional ultrasound were processed by a novel segment algorithm. Radiologists who were blind to the histology results were invited to analyse the original and computerized images respectively. The sensitivity and specificity were calculated by means of a binary outcome using receiver operating characteristic(ROC) analysis. Results By using the segment algorithm, the quantity of the image was obviously improved, especially the margin and calcification of the masses. The diagnostic performance of the radiologists was also improved. The sensitivity rose from 70.32% to 90.52% while the specificity was 74.31%. The area under the ROC curve increased significantly (P<0.01) from 80.8% to 90.5%. Conclusions The proposed segmentation algorithm can improve the diagnosis performance of the radiologists by meliorating the quality of the ultrasound image.
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ING1 family is a candidate for tumor suppressor,which has three splicing isoforms named p47ING1a,p33ING1b,and p24ING1c. Study of the effect of different isoforms of ING1 on HeLa cells proliferation and its molecular mechanism would help further identifying the functional relationship of ING1 isoforms,and finding important genes regulated by ING1. Cell growth curve and cell cycle analysis were used to observe the effect of ING1a,ING1b,and ING1c on HeLa cells growth,and the result indicated that they could all inhibit HeLa cells growth by arresting cell cycle at G0/G1 phase. PCR method was used to construct the PHD domain deletions of ING1a and ING1b. ING1a,ING1b,ING1c and the PHD domain deletions 1a?C and 1b?C were then overexpressed in HeLa cells. p16INK4a,PTEN/p27Kip1 and p53/p21Waf1 protein levels were detected by Western blot. The result showed that ING1a,ING1b,ING1c,and 1a?C except for 1b?C induced p16INK4a protein expression,in which ING1c had the most powerful effect. Luciferase assay identified that overexpression of pcDNA3.1(+)-1a?C facilitated p16INK4a transcription through enhancing p16INK4a promoter activity,while pcDNA3.1(+)-1b?C repressed the p16INK4a promoter activity . In a word,it was found for the first time that except for the p53/p21Waf1 pathway,three splicing isoforms of ING1 family could also inhibit HeLa cells proliferation though upregulation of p16INK4a and PTEN,and the PHD domain deletion of ING1a enhanced p16INK4a transcription. These findings provide new clews to further study on the mechanisms of ING1 family suppressing cancer cells growth.
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Echinacea is a most famous "immune herb" in western countries, and continues to be the best selling herb for many years. For the last five years, our research group has cooperated with Institute of Medicinal Plants in Huairou District of Beijing, carrying out studies on Echinacea purpurea, which involved botany, cultivation, pharmacognosy, phytochemistry, quality control, pharmacology and toxicology of the species. Two other species introduced from Canada, Echinacea angustifolia and Echinacea pallida, were also included in the taxonomic, cultivated and pharmacognostic studies. The results acquired have opened up the path to introduce Echinacea species into Traditional Chinese Medicine, thus established the possibility of developing more promising drugs from them.
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Object To provide a basis for the identification and development of Echinacea angustifolia DC Methods Pharmacognostical studies were carried out by phytotomy, macroscopic and microscopic analysis Results Detailed description of its pharmacognostical characteristics were accomplished and described Conclusion The results can be used for quality standardization of commercial product of E angustifolia
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Objective To investigate the preventive effect of spironolactone on hepatic fibrosis. Methods Ninety SD rats were randomly divided into three groups. Control group consisted of 8 rats that , fed by normal food, were injected with peanut oil subcutaneously. Model group consisted of 42 rats whose liver fibrosis was induced by compound factors. Spiro nolactone-prevention group consisted of 40 rats that were given 100 mg?kg -1 spironolactone per day, by the same methods of making models as those of the model group. At the end of weeks 2, 4, 6 and 8, 8 rats were randomly taken out of model group and spironol actone group and then were sacrificed. The expressions of TGF- ? 1 , PDGF- BB and ? -SMA in hepatic tissues were detected with immunohistochemical met hods. Results The expressions of TGF- ? 1 , PDGF-BB a nd ? -SMA in spironolactone group decreased greatly than those in model gro up ( P
