Recently a COVID-19 pneumonia pandemic caused by a novel coronavirus 2019-nCoV has broken out over the world. In order to better control the spread of the pandemic, there’s an urgent need to extensively study the virus’ origin and the mechanisms for its infectivity and pathogenicity. Spike protein is a special structural protein on the surface of coronavirus. It contains important information about the evolution of the virus and plays critical roles in the processes of cellular recognition and entry. In the past decades, spike protein has always been one of the most important objects in research works on coronaviruses closely related to human life. In this review we introduce these research works related to spike proteins, hoping it will provide reasonable ideas for the control of the current pandemic, as well as for the diagnosis and treatment of COVID-19.
ObjectiveTo evaluate the stability of the fixation technique for the crossed rods consisting of occipital plate and C2 bilateral lamina screws by biomechanical test.MethodsSix fresh cervical specimens were harvested and established an atlantoaxial instability model. The models were fixed with parallel rods and crossed rods after occipital plate and C2 bilateral laminae screws were implanted. The specimens were tested in the following sequence: atlantoaxial instability model (unstable model group), under parallel rods fixation (parallel fixation group), and under crossed rods fixation (cross fixation group). The range of motion (ROM) of the C0-2 segments were measured in flexion-extension, left/right lateral bending, and left/right axial rotation. After the test, X-ray film was taken to observe the internal fixator position.ResultsThe biomechanical test results showed that the ROMs in flexion-extension, left/right lateral bending, and left/right axial rotation were significantly lower in the cross fixation group and the parallel fixation group than in the unstable model group (P<0.05). There was no significant difference between the cross fixation group and the parallel fixation group in flexion-extension and left/right lateral bending (P>0.05). In the left/right axial rotation, the ROMs of the cross fixation group were significantly lower than those of the parallel fixation group (P<0.05). After the test, the X-ray film showed the good internal fixator position.ConclusionThe axial rotational stability of occipitocervical fusion can be further improved by crossed rods fixation when the occipital plate and C2 bilateral lamina screws are used.
Objective To analyze the risk factors for ventilator-associated pneumonia( VAP) in adult patients undergoing cardiac surgery with cardiopulmonary bypass ( CPB) . Methods A total of 127 consecutive adult patients who received postoperative ventilation for more than 48 hours between January 2002 and June 2008 in the cardiac surgical intensive care unit( CSICU) were included in this study. The patients were assigned into a VAPgroup( n =64) and a control group( n = 63) . Pre-, intra-, and postoperative factors were collected and analyzed between two groups, and the multivariate analysis( logistic regression)were used to identify the risk factors of VAP. Results The overall incidence of VAP was 5.1%. The mortality of VAP was 28. 1% . Compared to the control group, the patients in the VAP group had longer duration of cardiopulmonary bypass time, ventilation time, more blood products usage and the duration of stay in CSICU( P lt; 0. 001) , higher morbidity of low cardiac output syndrome and tracheotomy( P lt; 0. 01) and higher rate of aortic surgery and mortality( P lt; 0. 05) . The preoperative left ventricular ejection fraction ( LVEF) and postoperative oxygenation index( PaO2 /FiO2 ) were lower in the VAP group than those of the control group( P lt; 0. 001) . Five variables were found to be significantly related to the development of VAP by multivariate analysis: CPB time gt; 120 min( OR = 6. 352, P = 0. 000) ; PaO2 /FiO2 lt; 300 mm Hg( OR =3. 642, P = 0. 017) , transfusion of blood products ≥1500 mL( OR = 5. 083, P = 0. 039) , ventilation time≥5 days( OR = 9. 074, P = 0. 047) and tracheotomy( OR = 19. 899, P = 0. 021) . A total of 102 pathogens were obtained by sputum culture in 64 VAP patients. There were 62( 60. 8% ) cases of gram negative bacilli, 19 cases( 18. 6% ) of gram positive cocci and 21( 20. 6% ) cases of eumycetes. Conclusion This study shows that the cardiopulmonary bypass time, ventilation time, hypoxemia, blood products transfusion and tracheotomy are risk factors most likely associated with VAP development.