COVID-19 Asymptomatic Infection Estimation

BackgroundMounting evidence suggests that there is an undetected pool of COVID-19 asymptomatic but infectious cases. Estimating the number of asymptomatic infections has been crucial to understand the virus and contain its spread, which is, however, hard to be accurately counted. MethodsWe propose an approach of machine learning based fine-grained simulator (ML-Sim), which integrates multiple practical factors including disease progress in the incubation period, cross-region population movement, undetected asymptomatic patients, and prevention and containment strength. The interactions among these factors are modeled by virtual transmission dynamics with several undetermined parameters, which are determined from epidemic data by machine learning techniques. When MLSim learns to match the real data closely, it also models the number of asymptomatic patients. MLSim is learned from the open Chinese global epidemic data. FindingsMLSim showed better forecast accuracy than the SEIR and LSTM-based prediction models. The MLSim learned from the data of Chinas mainland reveals that there could have been 150,408 (142,178-157,417) asymptomatic and had self-healed patients, which is 65% (64% - 65%) of the inferred total infections including undetected ones. The numbers of asymptomatic but infectious patients on April 15, 2020, were inferred as, Italy: 41,387 (29,037 - 57,151), Germany: 21,118 (11,484 - 41,646), USA: 354,657 (277,641 - 495,128), France: 40,379 (10,807 - 186,878), and UK: 144,424 (127,215 - 171,930). To control the virus transmission, the containment measures taken by the government were crucial. The learned MLSim also reveals that if the date of containment measures in Chinas mainland was postponed for 1, 3, 5, and 7 days later than Jan. 23, there would be 109,039 (129%), 183,930 (218%), 313,342 (371%), 537,555 (637%) confirmed cases on June 12. ConclusionsMachine learning based fine-grained simulators can better model the complex real-world disease transmission process, and thus can help decision-making of balanced containment measures. The simulator also revealed the potential great number of undetected asymptomatic infections, which poses a great risk to the virus containment. FundingNational Natural Science Foundation of China.

Research on the correlation between Chinese medical syndrome types and objective indices of Wilson's disease / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the correlation between Chinese medical syndrome types of Wilson's disease (WD) and clinical materials as well as physical and chemical indices.</p><p><b>METHODS</b>Totally 116 WD patients were typed by Chinese medical syndrome. The correlation between Chinese medical syndrome types and clinical materials as well as physical and chemical indices were analyzed using binary stepwise Logistic regression by SPSS 19.0 Software, taking the common Chinese medical syndrome types as the dependent variable and clinical materials as well as physical and chemical indices as the independent variables.</p><p><b>RESULTS</b>Gan-Galibladder dampness-heat syndrome (GGDHS, 35.3%). Gan-stagnation and Pi-deficiency syndrome (GSPDS, 13.8%), Gan-Shen yin deficiency syndrome (GSYDS, 13.8%), and phlegm-dampness retention syndrome (PDRS, 12.1%) were most often seen. GGDHS was positively correlated with grade of K-F ring, total bilirubin (TBIL), alanine transaminase (ALT), laminin (LN) (P < 0.01). GSYDS was positively correlated with TBIL (P < 0.01). PDRS was positively correlated with clinical types, ceruloplasmin (CP), aspartate aminotransferase (AST), and total protein (TP) (P < 0.01, P < 0.05). Qi blood deficiency syndrome was positively correlated with disease course, blood ammonia, blood urea nitrogen (BUN), and LN (P < 0.01, P < 0.05).</p><p><b>CONCLUSIONS</b>Chinese medical syndrome types were correlated with clinical materials, physical and chemical indices in WD patients, which could provide experimental reference for Chinese medical syndrome typing. GGDHS, GSPDS, GSYDS, and PDRS were most often seen.</p>

Isolation of gastric cancer stem cells based on colony morphology and detection of their sensitivity to 5-fluorouracil / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the sensitivity of gastric cancer stem cells (GCSCs) to 5-fluorouracil (5-FU), and to explore the cytological mechanism of drug-resistance of gastric cancer.</p><p><b>METHODS</b>Immunohistochemical staining was employed to examine expression of stem cell marker CD44 and drug-resistance protein thymidylate synthase (TS) in 71 cases with gastric cancer. Based on morphology of cell colonies derived from AGS gastric cell line, colonies consisting of GCSCs were isolated, and expression of CD44 and TS, as well as self-renewal capacity of GCSCs were detected. Sensitivity of GCSCs to 5-FU was examined through CCK-8 assay.</p><p><b>RESULTS</b>The positive rates of CD44 and TS were 59.2% (42/71) and 56.3% (40/71) in gastric cancer, and expression of CD44 was associated with that of TS (χ(2)=12.76, P<0.01; Kappa=0.41). Serial sections indicated that CD44+ cancer cells simultaneously expressed TS. AGS developed morphologically diverse colonies, and the GCSCs colonies exhibited a tight and regular shape, which were called holoclone. Holoclones expressed CD44 and TS strongly, possessing capacity of robust self-renewal and forming a lot of second passage clones after incubation. Subclones expressed CD44 and TS weakly, forming less second passage clones. Paraclones almost did not express CD44 and TS, forming no second passage clone after incubation. Affected by 5-Fu, three holoclones showed less growth inhibition compared with another colony type and wild-type AGS cells. Furthermore, IC50 of 5-FU for three holoclones was (113.43±5.81), (272.68±25.75) and (118.14±17.75) μmol/L respectively, which were significantly higher than that of one subcolony type [(16.97±1.01) μmol/L] and AGS cells [(27.52±0.59) μmol/L] (all P<0.05).</p><p><b>CONCLUSIONS</b>GCSCs possess lower sensitivity to 5-FU, and may play a critical role in drug-resistance of gastric cancer.</p>

Morphological observation of human gastric cancer cell SGC-7901 clones and identification of gastric cancer stem cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To dynamically investigate the morphology of human gastric cancer SGC-7901 cell clones, and then compare the tumorigenic ability of different clones in order to identify the tumor stem cell clones.</p><p><b>METHODS</b>Clones derived from gastric cancer SGC-7901 cells were assessed by morphological observation, and the clone formation rate and proportion of each clone were calculated. The expression of CD44 and CDX2 in different clones was detected by immunofluorescence microscopy and Western blot. Furthermore, different clones were isolated and cultured, and their self-renewal property was assayed. Cells of different clones were subcutaneously inoculated into nude mice and the tumorigenic ability of each group was determined.</p><p><b>RESULTS</b>Clones derived from gastric cancer SGC-7901 cells had three types, i.e. clones of tight, transitional and loose types. The total clone formation rate was (9.80 ± 1.07)%, and the proportion of tight, transitional and loose type clones was 10.2%, 56.0% and 33.8%, respectively. The results of immunofluorescence microscopic examination showed that the signal of CD44 was significantly stronger in the tight clones than in the transitional and loose clones, however, the signal of CDX2 was weakest in the tight colonies. The results of Western blot were consistent with that of immunofluorescence microscopic observation. SGC-7901 cells of tight clones possessed strong ability of self-renewal and in vivo tumorigenicity in the nude mice.</p><p><b>CONCLUSION</b>SGC-7901 cell clones vary in morphology and differentiation, and the tight type clones may include rich gastric cancer stem cells.</p>

Clinical analysis of 5 patients with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes / 中华神经医学杂志

Objective To explore the clinical data,muscle pathological findings and recent follow-up results of 5 patients being diagnosed as having mitochondrial encephalopathy,lactic acidosis,and stroke-like episodes (MELAS).Methods A retrospective analysis was carried out on the clinical manifestations,sero-enzymology,electrophysiology,iconography and muscle biopsy pathology,and recent follow-up results of 5 patients with MELAS,who admitted to our hospital from December 2008 to June 2011.Results Headache as first symptom appeared in 3 patients,hemiparesis as first symptom in 1 patient and upper gastrointestinal bleeding in 1.The total body seizure in the course was noted in 4 patients and psychiatric symptoms in 2.The creatine kinase level was normal in 4 with one being mildly elevated.Four patients were observed no abnormal electromyography with one having myogenic lesions.Brain MRI showed significant abnormality in 5 patients,mainly presented as permanent cerebral infarction and cerebral atrophy.Five patients were found strongly SDH-reactive blood vessels (SSVs) in muscle tissue pathological staining and the SSVs of CCO (+).After mitochondrial protection treatment,follow-up for six months showed that 3 patients has been restored to normal work and mildly improvement was noted 2 patients.Conclusion The brain MR imaging of 5 patients with MELAS is significantly abnormal,and muscle biopsy pathology and tissue enzymatic staining are important methods in diagnosing the disease; generally,the disease is a benign course.

CoTrade: Confident Co-Training With Data Editing.

Co-training is one of the major semi-supervised learning paradigms that iteratively trains two classifiers on two different views, and uses the predictions of either classifier on the unlabeled examples to augment the training set of the other. During the co-training process, especially in initial rounds when the classifiers have only mediocre accuracy, it is quite possible that one classifier will receive labels on unlabeled examples erroneously predicted by the other classifier. Therefore, the performance of co-training style algorithms is usually unstable. In this paper, the problem of how to reliably communicate labeling information between different views is addressed by a novel co-training algorithm named COTRADE. In each labeling round, COTRADE carries out the label communication process in two steps. First, confidence of either classifier's predictions on unlabeled examples is explicitly estimated based on specific data editing techniques. Secondly, a number of predicted labels with higher confidence of either classifier are passed to the other one, where certain constraints are imposed to avoid introducing undesirable classification noise. Experiments on several real-world datasets across three domains show that COTRADE can effectively exploit unlabeled data to achieve better generalization performance.

Diagnosis value of urodynamics in patients with benign prostate hypertrophy / 医用生物力学

Objective To evaluate the diagnosis value of urodynamics in patients with benign prostate hypertrophy(BPH).Methods With urodynamic device,the full set of urodynamic exam was administrated in 427 patients with BPH,and the externalsphincter urethral myogram was monitored simultaneously in pressure-flow studies(PFS).The umdynamic finding such as Qmax 、Pdet-Qmax、Popen、DS(descending slope) and post-voiding residual(PVR)were recorded,as well as the situation of bladder detrusor constraction and bladder compliance and urethral sphincter coordination. The bladder outflow obstruction was diagnosed by A-G nomogram，P-Q plot and DS.The IPSS score and prostate volume were also acquired. Results The diagnostic rate of BOO is 81.5％,among them concomitantly detrusor muscle impair in 117 cases(27.4％), decreased bladder compliance in 162 case (37.9％)，urethral sphincter dyssynergia in 148 cases(34.7％)，and unstable bladder in l64 cases (38.4％). The increase degree of BOO show an increasing tendency with urodynamic findings such as Qmax ,Pdet-Qmax,Popen,DS and IPSS score and prostatic volume respectively，however a decreasing tendency with Qmax and bladder compliance. Conclusions The urodynamic exam plays an important role in diagnosis of BOO.There is a positive relation among degree of BOO with urodynamic finding such as Pdet-Qmax,Popen,DS and IPSS score and prostatic volume,however，negative relation with Qmax and bladder compliance respectively.

Shanghai multi-organ solution in preservation of rat liver: An experimental study / 第二军医大学学报

Objective: To observe the preservative effect of Shanghai-mutil-organ (SMO) solution on rat liver and to assess the feasibility of SMO solution in preserving isolated human livers. Methods: SD rats were randomly divided into 3 groups according to the preservation solutions: SMO group, UW ( University of Wisconsin Solution) group, and HTK (Histidinetryptophan-ketoglutarate solution) group. The simple cold storage liver model was established with isolated rat liver and the liver samples from each group were preserved with the 3 solutions for 8 h, 16 h, 24 h and 36 h. The energy metabolism was analyzed in all the samples and the morphological changes and hepatocytes apoptosis were observed after different preservation periods. Results: The liver tissue contents of ATP, TAN, and AEC in SMO group were significantly higher than those in HTK group at 16 h, 24 h, and 36 h (P<0.05); the contents in SMO group were similar to those in UW group. Histological examination showed that the tissue damage in SMO group was milder than that in HTK group; the damages in SMO group and UW group were similar except that the swelling of cells in SMO group was severer than that in UW group. Apoptosis index in SMO group was lower than that in HTK group at 24 h and 36 h(P< 0.05); there was no significant difference in apoptosis index between SMO group and UW group. Conclusion: SMO solution has a similar preservative effect on rat liver to that of UW solution, only with more severe cell swelling than the latter. The effect of SMO solution is better than that of HTK solution.

Diagnosis value of urodynamics in patients with benign prostate hypertrophy / 医用生物力学

Objective To evaluate the diagnosis value of urodynamics in patients with benign prostate hypertrophy(BPH).Method With urodynamic device,the full set of urodynamic exam was administrated in 427 patients with BPH,and the externalsphincter urethral myogram was monitored simultaneously in pressure-flow studies(PFS).The umdynamic finding such as Q_(max),P_(det)-Q_(max),DS(descending slope)and post-voiding residual(PVR)were recorded,as well as the situation of bladder detrusor constraction and bladder compliance and urethral sphincter coodination.The bladder outflow obstruction was diagnosed by A-G nomogram,P-Q plot and DS.The IPSS score and prostate volume were also acquired.Results The diagnostic rate of BOO is 81.5%,among them concomitantly detrusor muscle impair in 117 cases (27.4%),decreased bladder compliance in 162 case(37.9%),urethral sphincter dyssynergia in 148 cases(34.7%),and unstable bladder in 164 cases(38.4%).The increase degree of BOO show an increasing tendency with urodynamic finding such as Q_(max),P_(det)-Q_(max),P_(open),DS,IPSS score and prostatic volume respectively,but a decreasing tendency with Q_(max) and bladder compliance.Conclusions The urodynamic exam plays an important role in diagnosis of BOO.There is a positive relation among degree of BOO with urodynamic findings such as P_(det)-Q_(max),P_(open),DS and IPSS score and prostatic volume,however,a negative relation with Qmax and bladder compliance respectively.

Diagnosis value of urodynamics in patients with benign prostate hypertrophy / 医用生物力学

Objective To evaluate the diagnosis value of urodynamics in patients with benign prostate hypertrophy(BPH).Method With urodynamic device,the full set of urodynamic exam was administrated in 427 patients with BPH,and the externalsphincter urethral myogram was monitored simultaneously in pressure-flow studies(PFS).The umdynamic finding such as Q_(max),P_(det)-Q_(max),DS(descending slope)and post-voiding residual(PVR)were recorded,as well as the situation of bladder detrusor constraction and bladder compliance and urethral sphincter coodination.The bladder outflow obstruction was diagnosed by A-G nomogram,P-Q plot and DS.The IPSS score and prostate volume were also acquired.Results The diagnostic rate of BOO is 81.5%,among them concomitantly detrusor muscle impair in 117 cases (27.4%),decreased bladder compliance in 162 case(37.9%),urethral sphincter dyssynergia in 148 cases(34.7%),and unstable bladder in 164 cases(38.4%).The increase degree of BOO show an increasing tendency with urodynamic finding such as Q_(max),P_(det)-Q_(max),P_(open),DS,IPSS score and prostatic volume respectively,but a decreasing tendency with Q_(max) and bladder compliance.Conclusions The urodynamic exam plays an important role in diagnosis of BOO.There is a positive relation among degree of BOO with urodynamic findings such as P_(det)-Q_(max),P_(open),DS and IPSS score and prostatic volume,however,a negative relation with Qmax and bladder compliance respectively.

Activation of CXCR4 in human glioma stem cells promotes tumor angiogenesis / 中华病理学杂志

<p><b>OBJECTIVE</b>To isolate, culture and identify glioma stem cells from human malignant glioma cell line U87, and investigate the changes of pro-angiogenic factors production by glioma stem cells followed by activation of CXCR4 and observe their tumorigenesis as well as the expression of vascular endothelial growth factor when implanted into nude mice.</p><p><b>METHODS</b>The ratio of CD133 positive cells was detected by flow cytometry. Magnetic separation of CD133 positive cells was carried out on the magnetic cell sorting system (MACS). Expression of nestin, glial fibrillary acidic protein (GFAP) and CXCR4 on tumorspheres was detected by indirect immunofluorescence under confocal laser scanning microscopy. The functional activation of CXCR4 was assessed by calcium mobilization experiments. ELISA was used to detect the production of vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) in conditioned medium. Glioma stem cells were implanted into nude mice to assess their tumorigenesis ability and the expression of VEGF.</p><p><b>RESULTS</b>The ratio of CD133 positive cells with stem cell property was 0.5% in U87 cells. Activation of CXCR4 on glioma stem cells induced calcium mobilization and increased VEGF and IL-8 protein secretion. CD133 positive cells secreted more VEGF and IL-8 than their negative counterparts in vitro. Tumors derived from CD133 positive cells grew more rapidly and expressed elevated level of VEGF than their negative counterparts.</p><p><b>CONCLUSIONS</b>There are a small fraction of glioma stem cells in human glioblastoma cell line U87. Expressing functional CXCR4 and secreting more pro-angiogenic factors may be involved in tumor angiogenesis mediated by glioma stem cells.</p>

Effect of SMO preservation solution on apoptosis and energy metabolism in canine kidneys during cold storage / 中华器官移植杂志

0.05).The activity of Na~+-K~+ ATPase in SMO group was significantly higher than that in HTK group at 72 h(P

Polymorphism of Escherichia coli Isolated from the Fecal / 微生物学通报

In this study, three methods for identification of E.coli were compared. The conventional method was employed to select and identify the suspicious E.coli isolates from a fecal sample. PCR based ARDRA analysis was then carried out to distinguish these E.coli isolates, E.coli MG1655 and other bacterial species. All the potential E.coli isolates and E.coli MG1655 had the identical ARDRA banding pattern while the other bacterial species showed the different patterns.The result indicated that the ARDRA analysis was consistent with the traditional method for identification of E.coli and could be the practical method for distinguishing E.coli from other intestinal bacterial species. The ERIC-PCR analysis provided abundant polymorphism between different E.coli isolates, and might be a powerful approach for elucidating the genetic diversity among isolates of the same species.