Structural basis for repurpose and design of nucleoside drugs for treating COVID-19

SARS-CoV-2 has caused a global pandemic of COVID-19 that urgently needs an effective treatment. Nucleoside analog drugs including favipiravir have been repurposed for COVID-19 despite of unclear mechanism of their inhibition of the viral RNA polymerase (RdRp). Here we report the cryo-EM structures of the viral RdRp in complex with favipiravir and two other nucleoside inhibitor drugs ribavirin and penciclovir. Ribavirin and the ribosylated form of favipiravir share a similar ribose scaffold that is distinct from penciclovir. However, the structures reveal that all three inhibitors are covalently linked to the primer strand in a monophosphate form despite the different chemical scaffolds between favipiravir and penciclovir. Surprisingly, the base moieties of these inhibitors can form mismatched pairs with the template strand. Moreover, in view of the clinical disadvantages of remdesivir mainly associated with its prodrug form, we designed several orally-available remdesivir parent nucleoside derivatives, including VV16 that showed 5-fold more potent than remdesivir in inhibition of viral replication. Together, these results demonstrate an unexpected promiscuity of the viral RNA polymerase and provide a basis for repurpose and design of nucleotide analog drugs for COVID-19. One Sentence SummaryCryo-EM structures of the RNA polymerase of SARS-CoV-2 reveals the basis for repurposing of old nucleotide drugs to treat COVID-19.

Structural basis for repurposing a 100-years-old drug suramin for treating COVID-19

The COVID-19 pandemic by non-stop infections of SARS-CoV-2 has continued to ravage many countries worldwide. Here we report the discovery of suramin, a 100-year-old drug, as a potent inhibitor of the SARS-CoV-2 RNA dependent RNA polymerase (RdRp) through blocking the binding of RNA to the enzyme. In biochemical assays, suramin and its derivatives are at least 20-fold more potent than remdesivir, the currently approved nucleotide drug for COVID-19. The 2.6 [A] cryo-EM structure of the viral RdRp bound to suramin reveals two binding sites of suramin, with one site directly blocking the binding of the RNA template strand and the other site clash with the RNA primer strand near the RdRp catalytic active site, therefore inhibiting the viral RNA replication. Furthermore, suramin potently inhibits SARS-CoV-2 duplication in Vero E6 cells. These results provide a structural mechanism for the first non-nucleotide inhibitor of the SARS-CoV-2 RdRp and a rationale for repurposing suramin for treating COVID-19. One Sentence SummaryDiscovery and mechanism of suramin as potent SARS-CoV-2 RNA polymerase inhibitor and its repurposing for treating COVID-19.

Establishment and evaluation of a triple-color human papillomavirus pseudovirion neutralization assay / 中华预防医学杂志

Objective@#To establish a triple-color pseudovirion-based neutralization assay (PBNA) and evaluate its capability of detecting immunogenicity of the sera generated by the immunization of HPV 9-valent vaccine.@*Methods@#HPV pseudovirus (PsVs) 6/11/16/18/31/33/45/52/58 with the encapsidated fluorescence expressing red fluorescent plasmid N31-MCHREEY, green fluorescent N31-EGFP or blue fluorescent N31-mTagBFP were generated. The concentration of HPV PsVs and the infection titers of HPV PsVs were detected by double-antibody sandwich ELISA and TCID50, respectively. The single- and triple color HPV 16/33/45 PsVs were used to detect the neutralization titers of mice sera immunized with HPV 9-valent vaccine and confirmed the accuracy and specificity of the triple-color PBNAs. Then, the single- and triple color HPV 6/11/18/31/33/45/52/58 PsVs were employed to detect the neutralization titers of cynomolgus macaques sera immunized with HPV 9-valent vaccine and determined whether the triple-color PBNAs could be applied to evaluate the immunogenicity of the sera generated by the immunization of HPV9-valent vaccine.@*Results@#The concentration of HPV16 PsVs encapsulating green, red or blue fluorescent plasmid was 5.0 to 6.0 μg/ml and HPV6/11/18/31/33/45/52/59 triple-color HPV PsVs was about 1.0 to 3.0 μg/ml. 9 types HPV PsVs containing EGFP, Mcherry or mTagBFP reporter plasmid were obtained and the concentration can meet the need of neutralization detection. 9 types single-color fluorescent HPV PsVs had similar infectivity against 293FT cells with the infection titer values between 1×104 and 1×105. The results of PBNAs showed that there was no significant difference in the anti-HPV neutralization titers of mice sera induced by HPV 9-valent vaccine between single-color and triple-color HPV16/33/45 PsVs (P>0.05). Similarly, there was also no significant difference in the anti-HPV neutralization titers of cynomolgus macaques sera induced by HPV 9-valent vaccine between single-color and triple-color HPV6/11/18/31/33/45/52/58 PsVs (P>0.05).@*Conclusion@#We successfully established the triple-color PBNAs and verified the accuracy and specificity of triple-color PBNAs consistent with single-color PBNAs. The triple-color PBNAs can be applied to evaluate the immunogenicity of HPV 9-valent vaccine's immune serum.

Review for progress and current status of human papillomavirus prophylactic vaccine / 中国生化药物杂志

Persistant infection of high-risk human papillomavirus (HPV) is the primary cause leading to cervical cancer, which is ranked as second cancer threatening the health of women following breast cancer.Development of HPV vaccine is very important because there is no effective therapeutics for cervical cancer.Three currently licensed HPV vaccines based on major capsid protein L1 in the foreign market confered good safety and efficacy in clinical trials, but the current price is expensive due to high cost, which limits the wide application in developing countries.So far, the vaccines have not been launced in China market.Here, we review the progress and the current status of the HPV vaccine, which will attract the readers’ interest on the forthcoming emergence of HPV vaccine in China.

The microsurgical anatomic research of the internal auditory canal area on the retrosigmold approach / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To evaluate the safety of the circular round window and discus anatomic landmarks of posterior wall of internal auditory canal by investigating the microscopic anatomy of internal auditory canal area of the retrosigmold approach, which can provide the anatomical basis for acoustic neutrinomas surgery.@*METHOD@#Fifteen adult cadaver heads (30 sides) fixed with formalin were used in the study. The retrosigmold approach operations were imitated to dissect the blood vessels and nerves in internal auditory canal area by opening round bony window and removing posterior wall of internal auditory canal.@*RESULT@#Fifteen specimens of 30 sides circular bone window were opened without injury with transverse sinus and sigmoid sinus. The vertical distance between the highest point of bone window margo superior and the lowest point of transverse sinus margo inferior was (4.02 ± 0.32) mm. The vertical distance from the most anterior point of bone window leading edge to the most posterior point of sigmoid sinus trailing edge was (6.31 ± 0.43) mm. The internal auditory canal tubercle located in the anterior superior position of internal auditory canal. The vertical distance from the highest point of internal auditory canal tubercle to the upper margin of internal auditory canal was (2.31 ± 0.32) mm. To expose the whole internal auditory canal, the length and width of the internal auditory canal posterior wall removal was (7.29 ± 0.32) mm, (4.12 ± 0.29) mm. Within this removal range, no case of cochlea, semicircular canal or venous was injured in 30 specimens.@*CONCLUSION@#The method of opening round window through retrosigmold approach is simple, practial and convenient. With little variation and easiness of location, the sinternal auditory canal tubercle can be used in the identification of the internal auditory canal. When exposing the whole internal auditory canal, the removal scope of the posterior wall should be paid more attention to, in order to avoid the damage of cochlea, semicircular canal and jugular bulb.

Effect of Ipratropium bromide combined with atomization inhalation of budesonide on acute exacerbation of chronic obstructive pulmonary disease / 中华老年医学杂志

Objective To assess the clinical efffects off Ipratropium bromide combined with atomization inhalation of budesonide via a ventilator with a Y-shaped connector on acute exacerbation off chronic obstructive pulmonary disease (AECOPD).Methods A total off 62 AECOPD patients treated at our hospital from June 2013 to September 2014 were randomly divided into the experimental group (n=31,treated with ipratropium bromide combined with atomization inhalation of budesonide) and the control group (n =31,treated with the same amount of saline).Results The airway pressure of mechanical ventilation,the time of mechanical ventilation and the time of staying in the intensive care unit all showed significant differences between the experimental and control groups [(25.4±5.2) cmH2O vs.(38.1±3.4) cmH2O,(6.5±1.3) d vs.(6.8±1.4) d,(8.9±2.1) d vs.(9.5±1.5) d,t=10.934,0.960,1.108,respectively,P＜0.05 for all].The rate of tracheotomy was lower in the experimental group than in the control group (17/31 or 54.8％ vs.20/31 or 64.5％,x2 =0.603,P＜0.05).Conclusions Ipratropium bromide combined with budesonide inhalation under mechanical ventilation via a Y-shaped connector has ffavorable clinical effects on AECOPD.

Values of glycosylated hemoglobin in screening for patients with prediabetic state in Guangzhou region / 国际检验医学杂志

Objective To study the values of glycosylated hemoglobin in screening for patients with prediabetic state in Guang-zhou region .Methods 525 Guangzhou people who had accepted health examination were enrolled and were subjected to oral glucose tolerance test(OGTT) .BIO-RAD D-10 automatic glycosylated hemoglobin analyzer was employed to detect their glycosylated he-moglobin A1c(GHbA1c) .OGTT results were served as diagnostic criteria ,Receiver operator characteristic (ROC) curve analysis was performed to obtain the optimal threshold of GHbA1c in diagnosing impaired glucose regulation (IGR) .Results The optimal threshold of GHbA1c in diagnosing IGR was 5 .95% .The sensitivities of GHbA1c≥5 .95% and GHbA1c≥5 .7% in diagnosing IGR were 53 .3% and 84 .8% ,respectively ,while their specificities were 72 .8% and 31 .0% ,respectively .The difference of sensitivity between GHbA1c≥5 .95% combined with FPG≥5 .6 mmol/L and GHbA1c≥5 .7% alone in diagnosing IGR showed no statistical significance(P= 0 .406) ,while the specificity increased obviously (P= 0 .000) .Conclusion The criteria of GHbA1c≥5 .7% can be used for prediabetic state screening but not for diagnosis .GHbA1c≥5 .95% combined with FPG≥5 .6 mmol/L can be used effectively for prediabetic state screening in Guangzhou people .

Inhibitory effect of full-length spleen tyrosine kinase on invasion and metastasis of human laryngeal squamous cells / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study the effect of gene transfection of full length spleen tyrosine kinase (Syk (L)) on the biological behavior of malignant cancer cells.</p><p><b>METHODS</b>Eukaryotic expression vector pIRES2-EGFP-Syk (L) was constrauted and sequenc. Laryngeal carcinoma cell line Hep-2 were transfected with pIRES2-EGFP-Syk (L) vectors or blank vectors. The expressions of mRNA and protein were examined by real time fluorescence quantitative polymerase chain reaction (Q-RT-PCR) and Western blot analysis. CCK-8 method was used for evaluating cell proliferation, Transwell for cell invasion capacity in vitro, and tumor formation in nude mice for in vivo tumorigenicity.</p><p><b>RESULTS</b>pIRES2-EGFP-Syk (L) vectors were successfully construct and transfected to Hep-2 cells. Q-PCR showed that mRNA expression level in Hep-2 cells transfected with Sky (L) (28.395 ± 0.067) was higher than those in Hep-2-neo cells transfected with blank vectors (3.891 ± 0.021) and Hep-2 cells with no transfection (1.005 ± 0.012), with statistically significant difference (F = 104.02, P < 0.01). Western blot showed that protein expression level of transfected-Sky (L) cells (0.821 ± 0.047) was significantly higher than those of Hep-2-neo cells (0.558 ± 0.031) and Hep-2 cells (0.468 ± 0.031), and the difference was statistically significant (F = 112.32, P < 0.01) ; CCK-8 assay showed OD value (1.390 ± 0.067) of transfected-Sky (L) cells was lower than those of Hep-2-neo cells (1.830 ± 0.067) and Hep-2 cells (1.920 ± 0.040), and the difference was statistically significant (F = 107.64, P < 0.01). Transwell assay showed average cell number per field of transfected-Sky (L) cells (176.04 ± 22.32) was higher than those of Hep-2-neo cells (301.02 ± 21.45) and Hep-2 cells (336.04 ± 26.01) with statistically significant difference (F = 123.46, P < 0.01). The volume (250.77 ± 34.83) mm(3) tumor formed from transfected-Sky (L) cells in nude mice, was less than those from Hep-2-neo cells (750.77 ± 40.83) mm(3) and Hep-2 cells (770.77 ± 30.83) mm(3), with statistically significant difference (F = 165.78, P < 0.01).</p><p><b>CONCLUSION</b>Down-regulation of Syk in Hep-2 cells is associated with the malignant biological behaviors of the cells. Syk (L) may be a potential target in gene therapy for laryngeal squamous cell carcinoma.</p>

Study of demonstrating main operative section of facial recess approach using double oblique multiplanar reconstruction on multislice CT / 中华放射学杂志

Objective To explore the method of demonstrating main operative section of facial recess approach with multi-slice CT by using double oblique muttiplanar reconstruction.MethodsSimilarly as surgical procedure of facial recess approach,30 (60 eras) normal temporal bones in cadavers were reconstructed to observe main operative sections and anatomical marks.Main images of operative section of facial recess approach were reconstructed using double oblique multiplanar reconstruction on multislice CT.With the reference of operative anatomical marks,the ratios of visibility of anatomical marks on the transverse plane,coronal plane,sagittal plane and double oblique were calculated and compared.The degree,of which major anatomical landmarks were displayed on the same plane ( axial,coronal,sagittal,or doubleoblique sagittal plane),was classified using the following criteria: level 4: 100％ of anatomical landmarks were presented in the same plane; level 3: 90％ to 99％ of anatomical landmarks were presented in the same plane; level 2: 80％ to 89％ of anatomical landmarks were presented in the same plane; level 1: 70％ to 79％ of anatomical landmarks were presented in the same plane ; level 0: ＜ 70％ of anatomical landmarks were presented in the same plane.Classification data were tested by chi-square test.Results Four key operative section were involved in facial recess approach,which were of oblique sagittal orientation.The central mark of the first key operative section was semicircular canal by using double oblique multi-planar reformation.On reconstructed images of the first key operative section,horizontal reference line was short process of incus,and the angle adjusting the reference line on the transverse plane was 22.15° ±5.22°.On the reconstructed images of the first key operative section,coronal reference line was tympanic segment of facial canal,and the angle adjusting the reference line on the coronal plane was 14.35° ± 4.02°.On the reconstructed images of the second key operative section,the central mark was fossa incudis,the horizontal reference line was short process of incus and the angle was 20.15° ± 5.52°,while the coronal reference line was tympanic segment of facial cana,and the angle was 13.15° ± 3.33°.On the reconstructed operative images of the third key section,the central mark was pyramidal eminence,the horizontal reference line was the horizontal portion of the facial nerve and the angle was 32.53° ±5.22°,while the coronal reference line was the tympanic segment of facial nerve,and the angle was 15.05° ± 4.43°.On the fourth reconstructed images of the key operative section,the central mark was the posterior border of round window,the horizontal reference line was the superior border of oval window,and the angle was 50.15° ± 8.02°,while the coronal reference line was the tympanic segment of facial nerve,and the angle was 15.25° ± 4.12°.For the four planes (double-oblique sagittal,axial,coronal,or sagittal plane),the results of the degree to which they could include the major anatomical landmarks in the same layer of the first section were: level 4 in 60 sides,level 2 in 12 sides and level 3 in 48 sides,level 2 in 15 sides and level 3 in 45 sides,level 3 in 10 sides and level 4 in 50 sides,respectively.The results of the second section were: level 4 in 60 sides,level 2 in 11 sides and level 3 in 49 sides,level 2 in 13 sides and level 3 in 47 sides,level 3 in 11 sides and level 4 in 49 sides,respectively.The results of the third section were: level 4 in 60 sides,level 2 in 10 sides and level 3 in 50 sides,level 2 in 11 sides and level 3 in 49 sides,level 3 in 9 sides and level 4 in 51 sides,respectively.The results of the fourth section were: level 4 in 60 sides,level 2 in 9 sides and level 3 in 51 sides,level 2 in 8 sides and level 3 in 52 sides,level 3 in 5 sides and level 4 in 55 sides,respectively.The four planes differed significantly in the degree to which they could include the major anatomical landmarks in the same layer ( x2 =123.3200,121.4231,122.4011,125.4213,all,P ＜ 0.05 ).The visibility ratio of every section is 100％ (60/60).Conclusion Double oblique multi-planar reformation is a new method to demonstrate landmarks of operative section of facial recess approach in one slice.The reconstructive images of operative section with double oblique multi-planer reconstruction may provide valuable information for operation.

Study of demonstrating main operative mark of transmastoid-epitympanum approach of the facial nerve using double oblique multi-planar reconstruction in multi-slice CT / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To explore a method of demonstrating the facial nerve anatomical landmarks under transmastoid and epitympanum approach with multi-slice CT using double oblique multi-planar reconstruction (MPR).@*METHOD@#Two temporal bone of a corpse were dissected, under transmastoid and epitympanum approach, to observe the anatomical landmarks of facial nerve. Based on that, the anatomical landmarks of facial nerve under transmastoid and epitympanum approach in 30 (60 ears) normal temporal bones of adult corpses were reconstructed using double oblique MPR in multi-slice CT. The achievement ratio was calculated and the differences among transverse plane, coronal plane, sagittal plane and double oblique were compared.@*RESULT@#The different part of facial nerve, such as mastoid segment, tympanum segment, pyramid segment, geniculate ganglion and the outer labyrinthine segment could be exposed clearly with the main anatomical landmarks, such as horizontal semicircular canal, epitympanic recess and cochleariform process through transmastoid and epitympanum approach. The image of anatomical landmarks could be showed in the same sections by double oblique multi-planar reconstruction. The double oblique multi-planar reconstruction to show the landmarks of facial nerve displaying on the same imaging is better than transverse plane, coronal plane and sagittal plane. The achievement ratio of every section is 100%.@*CONCLUSION@#Double oblique MPR is a new method to demonstrate anatomical landmarks through transmastoid and epitympanum approach in one slice. Combined with the operative approach and purpose, the reconstructive images with double oblique MPR can provide valuable information for operation.

Three-dimensional reconstruction of the optic canal-based on multislice helical CT: a comparison analysis with skull dissection of 40 postmortem cases.

Decompression operation of the optic canal via the nasal path under endoscope is widely used, but it is both a challenging and controversial method. Unsatisfactory results were largely associated with otolaryngologists' limited understanding of the real anatomical situations of the optic canal before operation. To provide otolaryngologists with the real situations and data preoperation, multislice helical CT was used to reconstruct the images of the optic canal. Using multislice helical CT-aided three-dimensional reconstructive methods in combination with direct anatomic measurement, we dissected and analyzed the shape of the optic canal and its anatomic relationship with the adjoining structures in 40 intact postmortem skull samples. The In-Space technique clearly showed the structure and the related region of the optic canal. The virtual endoscopy technique showed superbly the spatial appearance and topography of the inner optic canal and also gave the inner structure of the optic canal optically. There was no statistic difference in three-dimensional reconstructive data with that obtained by anatomical measurements and thus can be used to directly instruct the clinic operation. These results demonstrate that a combined In-Space technique with virtual endoscopy can accurately define the subtle structure and the related region of the optical canal. In conclusion, multislice helical CT-based three-dimensional reconstruction is of important value for clinical operations.

Three dimensional reconstruction study of multi-slice helical CT imaging on optic canal area / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To investigate the accuracy and clinical application of multi-slice spiral CT imaging on optic canal area.@*METHOD@#Forty intact specimens of human corpse head were tested with three dimensional reconstruction of multi-slice spiral CT imaging. The results of radiology and anatomy were compared on adjacent structures of optic canal interior wall and its developmental relationship with sphenoid sinus.@*RESULT@#(1) The high spatial resolution of integrity could be obtained with dimensional processing technique. The anatomical structure of optic canal and its surrounding area could be demonstrated clearly. (2) With the technique of virtual endoscopy, the interior reconstruction of optic canal could demonstrate the inner topography of optic canal, the reconstruction image of which was identical to that of the control subjects. (3) There was no significant difference between the data of multi-slice spiral CT imaging and that of anatomy (P > 0.05).@*CONCLUSION@#Associated application of dimensional processing technique and virtual endoscopy, not only can the subtle structures of optic canal be demonstrated and measured, but also the detailed information on spatial relationships of optic canal area can be provided for operation.