[Effect of different work rate increasing rate on the overall function evaluation of cardiopulmonary exercise testing I-peak parameters and changes in respiratory exchange rate].

Objective: To observe the effect of healthy volunteers different work rate increasing rate cardiopulmonary exercise test (CPET) on the peak exercise core indicators and the changes of respiratory exchange rate (RER) during exercise, to explore the effect of different work rate increasing rate on CPET peak exercise related indicators. Methods: Twelve healthy volunteers were randomly assigned to a moderate (30 W/min), a relatively low (10 W/min) and relatively high (60 W/min) three different work rate increasing rate CPET on different working days in a week. The main peak exercise core indicators of CPET data: VO2, VCO2, work rate (WR), breathe frequency(Bf), tidal volume (VT), ventilation (VE), heart rate (HR), blood pressure (BP), Oxygen pulse(O2P), exercise time and RER for each period of CPET were analyzed using standard methods. The ANOVA test and paired two-two comparison was performed on the difference of each index in the three groups of different work rate increasing rate. Results: Compared with the moderate work rate group, the peak work rate of the lower and higher work rate groups were relatively lower and higher, respectively ((162.04±41.59) W/min vs (132.92±34.55) W/min vs (197.42±46.14) W/min, P<0.01); exercise time was significantly prolonged and shortened ((5.69 ± 1.33) min vs (13.49 ± 3.43) min vs (3.56 ± 0.76) min, P<0.01); peak RER (1.27 ± 0.07 vs 1.18 ± 0.06 vs 1.33 ± 0.08, P<0.01~P<0.05) and the recovery RER maximum (1.72±0.16 vs 1.61±0.11 vs 1.81±0.14, P<0.01~P<0.05) were significantly decreased and increased. Conclusion: Different work rate increasing rate of CPET significantly change the Peak Work Rate, exercise time, Peak RER, and maximum RER during recovery. The CPET operator should choose an individualized work rate increasing rate that is appropriate for the subject, and also does not use a fixed RER value as a basis for ensuring safety, the subject's extreme exercise, and early termination of exercise.

[Effect of different work rate increasing rate on the overall function evaluation of cardiopulmonary exercise testing II- sub-peak parameters].

Objective: To observe the effect of healthy volunteers different work rate increasing rate cardiopulmonary exercise testing (CPET) on the sub-peak parameters . Methods: Twelve healthy volunteers were randomly assigned to a moderate (30 W/min), a relatively low (10 W/min) and relatively high (60 W/min) three different work rate increasing rate CPET on different working days in a week. The core indicators related to CPET sub-peak exercise of 12 volunteers were compared according to standard Methods: anaerobic threshold (AT), oxygen uptake per unit power (ΔVO2/ΔWR), oxygen uptake eficiency plateau,（OUEP), the lowest average of 90 s of carbon dioxide ventilation equivalent (Lowest VE/ VCO2), the slope of carbon dioxide ventilation equivalent (VE/ VCO2 Slope) and intercept and anaerobic threshold oxygen uptake ventilation efficiency value (VO2/ VE@AT) and the anaerobic threshold carbon dioxide ventilation equivalent value (VE/ VCO2@AT). Paired t test was performed on the difference of each parameter in the three groups of different work rate increasing rate. Results: Compared with the relatively low and relatively high work rate increasing rate group, the moderate work rate increasing rate group uptake eficiency plateau, (42.22±4.76 vs 39.54±3.30 vs 39.29±4.29) and the lowest average of 90 s of carbon dioxide ventilation equivalent (24.13±2.88 vs 25.60±2.08 vs 26.06±3.05) was significantly better, and the difference was statistically significant (P<0.05); Compared with the moderate work rate increasing rate group, the oxygen uptake per unit work rate of the relatively low and relatively high work rate increasing rate group increased and decreased significantly ((8.45±0.66 vs 10.04±0.58 vs 7.16±0.60) ml/(min·kg)), difference of which was statistically significant (P<0.05); the anaerobic threshold did not change significantly ((0.87±0.19 vs 0.87±0.19 vs 0.89±0.19) L/min), the difference was not statistically significant (P>0.05). Conclusion: Relatively low and relatively high power increase rate can significantly change the CPET sub-peak sports related indicators such as the effectiveness of oxygen uptake ventilation, the effectiveness of carbon dioxide exhaust ventilation, and the oxygen uptake per unit work rate. Compared with the moderate work rate increasing rate CPET, the lower and higher work rate increasing rate significantly reduces the effectiveness of oxygen uptake ventilation and the effectiveness of carbon dioxide exhaust ventilation in healthy individuals. The standardized operation of CPET requires the selection of a work rate increasing rate suitable for the subject, so that the CPET sub-peak related indicators can best reflect the true functional state of the subject.

[Clinical study on the characteristics of exercise pathophysiological in patients with severe heart failure].

Objective: The cardiopulmonary function of patients with chronic heart failure (CHF) was severely limited, but the holistic integrative exercise pathophysiology is still unclear. Methods: After signed the consent form, Eighty three patients with severe CHF from October 2016 to October 2017 in Fuwai Hospital were performed Ramp incremental loading program CardioPulmonary Exercise Testing (CPET), and 12 normal subjects served as control. CPET were performed according to standard of Harbor-UCLA MC and the circulatory, respiratory and metabolic parameters during CPET were measured and analyzed. Results: Peak oxygen uptake (Peak VO2) in CHF (14.33±2.69) ml/(min·kg), (44.25±14.74)%pred was significantly lower than control ((29.42±5.46) ml/(min·kg), (83.88±6.28)%pred). Other core parameters of CPET such as anaerobic threshold (AT), peak oxygen pulse, oxygen uptake efficiency platform (OUEP), the lowest of carbon dioxide output ventilation ratio (Lowest VE/VCO2), and carbon dioxide output ventilation slope (VE/VCO2 Slope) in CHF were significantly different with the control group(P<0.01). The core parameters of lung function, such as forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC, and carbon monoxide diffusion (DLCO) were significantly decreased (P<0.01). Systolic blood pressure during all stages of CPET in CHF was significantly lower than control group (P<0.05); Heart rate at AT, peak and recovery stages were significantly lower than control (P<0.01). Minute ventilation, tidal volume and respiratory frequency at rest, warm-up were significantly higher than control (P<0.05). Tidal volume at recovery was significantly higher than control (P<0.05). VO2 at AT, peak and recovery stages in CHF were significantly higher than control (P<0.01). Oxygen pulse at AT and peak were significantly higher than control (P<0.01). Pulse oxygen saturation during all stages of CPET in CHF were significantly lower than control (P<0.01). Conclusion: The decreased holistic functional capacity of cardiogenic CHF dominantly due to circulatory limitation, and secondly due to respiratory and metabolic limitation.

[The effectiveness of different respiration models to the amplitude of waveform information in arterial blood gas].

Objective: The objective is to find the characteristics of arterial blood sample waveform in different respiration models. Methods: Six post-operative patients with normal heart function and negative Allen test, were 4 male and 2 female, (59.00±16.64)year, (71.67±0.37)kg, left ventricular ejection fraction(LVEF) (61.33±2.16)%, had been placed the arterial catheterization and central venous catheterization for continuous collecting arterial in 3 different kinds of respiration models: normal breathing, no breathing and deep breathing. We selected two breaths cycles of waveform from each patient for data calculations of magnitudes and time interval. Compare the adjacent highest and lowest values of patients to verify whether there are periodic wave-like signal changes in arterial and venous blood gas in the three breathing states. In addition, statistical t-test analysis was performed on the change amplitude of the periodic wave-like signal of the patient's arterial and venous blood gas to compare whether there is a difference. Results: The heart beat numbers for drawing blood into pipe were 15-16, and all covered more than 2 breathing cycles. There were significant changes of arterial PaO2 (i.e. the highest high values compare to the next lowest values, P<0.05) in three different breathing models(normal, no breathing and high breathing), the magnitudes of which were (9.96±5.18)mmHg, (5.33±1.55)mmHg and (13.13±7.55)mmHg, with (8.09±2.43)%, (5.29±2.19)% and (10.40±2.68)% from their mean respectively. PO2 in venous blood gas did not show wavy changes under normal breathing, 20 s breath holding and high tidal volume ventilation. The amplitudes were (1.63 ± 0.41) mmHg, (1.13 ± 0.41) mmHg and (1.31 ± 0.67) mmHg, which were (3.91 ± 1.22)%, (2.92 ± 1.12)%, (3.33 ± 1.81)%, respectively, which were significantly lower than that of arterial blood gas under the same state, but there was no significant difference between groups. Conclusion: With continuous beat-by-beat arterial blood sampling and ABG analyzing method in three different breathing models, We obtain a clear evidence of the biggest periodic parameters ABG waveform in high breathing models, which followed by normal breathing models, no breathing was the smallest, and the wave variation amplitude of venous oxygen partial pressure was not obvious in the three respiratory states, which implies the oscillatory information of the arterial blood with comes from the gas exchanging in the lung.

[The experimental evidence of waveform information in arterial blood gas by beat-by-beat sampling method in human body-the differences of waveform information between arterial and venous blood samples].

Objective: The arterial blood with the oscillatory information comes from the right heart system after gas exchanging in the lung. However, the evidence of the waveform of venous ABG is lack. The objectives of this article are to compare the different information between arterial and venous beat-by-beat blood sample at the same time. Methods: Six post-operative patients with normal heart function and negative Allen test, had been placed the arterial catheterization and central venous catheterization directly connected to pre-heparin plasticpipes for continuous collecting arterial and venous blood. We twisted the 2 pipes into helix formation. After drawing arterial and venous blood with syringes in one heart beat with one helix at the same time, totally 15 heart beats, clipping the pipes with forceps, we put the helix pipe into icedwater at once and analyses PaO2, PaCO2, pH and SaO2 as soon as possible. We selected two breathscycles of waveform from each patient for data calculations of magnitudes and time interval. Results: The heart beat numbers for drawing blood into pipe were 15~16, and all covered more than 2 breathing cycles. There were significant changes of arterial PaO2(i.e. the highest high values compare to the next lowestvalues, P<0.05), but no significant changes in venous blood(P>0.05). The magnitudes of changing PaO2 in arterial and venous blood sample were (9.96±5.18)mmHg and (1.63±0.41)mmHg with significant variance(P=0.010), and they were (8.09±2.43)% and (3.91±1.22)%from their mean with significant variance(P=0.009) respectively. Conclusion: With continuous beat-by-beat arterial and venous blood sampling and ABG analyzing method at the same time, we obtain a clear evidence of periodic parameters ABG waveform, which following breathing cycle, but no clear ABG waveform of the periodic parameters in the venous blood samples, which implies the oscillatory information of the arterial blood with comes from the gas exchanging in the lung.

[Preliminary experimental study on the influence of different tidal volume and frequency of normal minute ventilation on the dynamic changes of carotid blood oxygen in living goats].

Objective: On the basis of preliminarily verifying the use of ultra-fast reaction polymer matrix optical fiber oxygen sensor and its measuring system to record the continuous and dynamic changes of carotid artery oxygen partial pressure (PaO2), in order to analyze and discuss the influence of lung ventilation on the continuous and dynamic changes of PaO2, we designed a whole animal experimental study in vivo. Methods: Four hybrid goats were selected, and the skin was cut and exposed directly under general anesthesia and tracheal intubation. The oxygen sensor, connected with the measuring system, was inserted directly into the left carotid artery to continuously record the dynamic changes of PaO2. With normal minute ventilation,mechanical ventilation is implemented through three tidal volumes: normal tidal volume (VT=15 ml/kg, Rf=20 bpm), half tidal volume (halved VT, doubled Rf) and double tidal volume (doubled VT, halved Rf). Each tidal volume was stable for 10~15 min respectively. We analyzed and calculated the average values of PaO2, the fluctuation magnitudes of PaO2 changes between breaths of last 180 s and the delay times of lung-carotid artery were. We analyzed the effects of different tidal volumes. Results: The heart rate and blood pressure of living goats were maintained stable during the mechanical ventilation experiment with normal ventilation volume Lung-carotid artery delay time is 1.4~1.8 s (about 3 heartbeats at this time). Under normal tidal volume of mechanical ventilation, the average value of PaO2 was (102.94±2.40, 99.38~106.16) mmHg, and the fluctuation range was (21.43±1.65, 19.21~23.59) mmHg, accounting for (20.80± 1.34, 18.65~22.22)% of the average value. Under the condition of halving tidal volume, the average value of PaO2 was maintained at (101.01±4.25, 94.09~105.66) mmHg, which was slightly decreased but not significant (P>0.05 compared with normal mechanical ventilation), but the fluctuation range of PaO2 was significantly reduced to (18.14±1.43, 16.46~20.05) mmHg, accounting for 17.5% of the average value. Under double tidal volume mechanical ventilation, although the average value of PaO2 increased slightly remained at (106.42±4.74, 101.19~114.08) mmHg (P>0.05 compared with normal mechanical ventilation and P<0.05 compared with half tidal volume mechanical ventilation), the fluctuation magnitude of PaO2 increased significantly to (26.58±1.88, 23.46~28.46)mmHg. Conclusion: Inspiration and expiration of normal lung ventilation are the initial factors for the increase and decrease of PaO2 in carotid artery. Under normal ventilation, halving tidal volume and doubling tidal volume significantly changed the fluctuation magnitude of PaO2, but the average value of PaO2 changed only slightly, while the lung-carotid delay time was similar.

[Ultra-fast response polymer optical fiber oxygen measurement device and its preliminary experimental report on continuous dynamic change of arterial oxygen partial pressure under mechanical ventilation in living animals].

Objective: We tried to implant the ultra-fast polymer optical fiber chemical oxygen sensor （POFCOS） into arterial blood vessel,connect with photoelectric conversion measurement system to record the continuous dynamic rapid changes of arterial PO2(PaO2) in whole living animals. It should be the experimental evidence for the new theory of holistic integrative physiology and medicine(HIPM) forexplain the mechanism of respiratory control and regulation in whole circusof respiration-circulation-metabolism. Methods: ①Fabrication of ultrafast POFCOS, calibration and its measuring system: The distal part of 2 m optical fiber was heated and pulled until it became a tapered tip. After cleaning and drying, the tip of 1 mm tapered optical fiber was dip-coated into the luminophore doped polymer solution, then was slowly pumped out while solvent was quickly evaporated to form an oxygen sensing tip, which was dried at room temperature for 24 hours. ②Animal experiments: Under general anesthesia and intubation, goatwas mechanically ventilated with 40%~60% oxygen. We exposed both right and left carotid arteries and the left femoral artery by skin cutting, and inserted the POFCOS directly into the arteries via indwelling catheter. The end of POFCOS were connected to the personal computer through optical fiber, excitation and detection Y-type optical fiber coupler through photoelectric conversion, so as we can realize the continuous dynamic response of living goat carotid PaO2 under mechanical ventilation. We mainly analyzed the intra-breath wave-form alternate increase and decrease of PaO2 and their time delay between lung and carotid arteries.We completes breathing control whole loop to explain the mechanism of mutual breathing and the switching of inspiration and exhalation. Results: The POFCOS has a very fast T90 response time was set 100 ms for liquid. When the heart rate of 40%~60% oxygen mechanical ventilated living goat was ~110 bpm, the PaO2 of left and right carotid artery showed a same wave-sizeup and down following with the inspiration and expiration of ventilator, with a range of up to 15 mmHg. There weresignificant noises of PaO2 change recorded in the left femoral artery. The lung-carotid artery time delay is 1.5~1.7 s after inhalation and exhalation, PaO2 at both left and right carotid arteries starts toincrease and decrease. After two-three heartbeats after the start of lung ventilation, thealternate up-down wave-form information of the arterialized pulmonary vein blood after pulmonary capillaries waspumpedby left ventricle to the position of peripheral chemoreceptors,thus realizing the whole cycle of inhalation and exhalation. It alternately interrupted inhalation, i.e. switching inhalation to exhalation, and then interrupted exhalation,i.e. switching exhalation to inhalation. Conclusion: The ultra-fast reactive implantableoxygen sensor and its measuring system can measure the physiological waveform changes of PaO2 in living animals, which can provide experimental evidence for explaining the mechanism of switching of inspiration-expiration in HIPM.

[Preliminary report on partial pressure changes of oxygen and carbon dioxide in umbilical artery and vein before and after the first breath in Chinese neonates II-The personalized analysis of partial pressure of oxygen and carbon dioxide difference between umbilical artery and vein at same time in same newborn].

Objective: In order to explore the mechanism of neonatal spontaneous breathing, the difference of oxygen and carbon dioxide between umbilical cord arteries and veins before the start of spontaneous breathing after birth has been analyzed among people. In this part, the related information is analyzed individually. Methods: After all fetal parents signed the informed consent before birth, and before the newborn was born and did not breathe, the umbilical cord was exposed as quickly as possible, and the heparinized arterial indwelling needle was inserted into the umbilical artery and umbilical vein in the direction of newborn and placenta, and then blood was taken continuously. Although dozens of mothers were selected,but only 3 cases were collected from Pua and Puv blood samplers at the same time for blood gas analysis and determination, and the differences and dynamic changes of umbilical vein and umbilical artery were calculated and analyzed. Results: In all 3 none spontaneous breathing newborns,PuvO2 was significantly higher than PuaO2 at the same time (P<0.01), with an average difference of (24.17±7.09) mmHg; while PuvCO2 was significantly lower than PuaCO2 (all P<0.01), with an average difference of (-7.67±3.70) mmHg.The difference of Puv-uaO2 was significantly higher than those of Puv-uaCO2 (P<0.05). Conclusion: PuaO2 decreases gradually with time (heartbeat frequency) before spontaneous breathing after the delivered fetus as a newborn, and it induces the first inhalation to start spontaneous breathing when it reaches the threshold of triggering breathing.

[Preliminary report on partial pressure changes of oxygen and carbon dioxide in umbilical artery and vein before and after the first breath in Chinese neonates I-The group difference of partial pressure of oxygen and carbon dioxide between umbilical artery and vein in newborns].

Objective: The fetus has no actual respiration, and the newborn begins to breathe after birth. We assume that the first breath dominantly generated by hypoxia. In this study, the changes and lowest limit of blood oxygen partial pressureof umbilical artery (PuaO2) after chemoreceptor were analyzed to explore the mechanism of neonatal spontaneous breathing. Methods: With signed consent form by all fetal parents before birth, 14 newborns successfully completed the umbilical artery or vein catheterization and drawn blood according to the heartbeat. All blood samples analyzed by blood gas analyzer,calculated and analyzed the similarities and differences between umbilical vein(Puv) and umbilical artery(Pua). Results: Although we completed 14 newborns, there were only 9 cases of umbilical artery samples and 8 cases of umbilical vein samples were collected. Only 3 cases collected both Pua and Puv blood samples at the same time (see serial paper II). PuaO2 in gradually decreased with time (heartbeat frequency), until Pua contracted after spontaneous breathing produced about 8~10 heartbeats, and then could not get enough blood samples. Only 3 newborns were able to take blood samples after spontaneous breathing for 8~10 heartbeats, and their PuaO2 were jumped to 186.0, 137.0 and 93.8 mmHg respectively. The mean value of PuaO2 was (25.94±6.79, 18.04~37.51)mmHg, the highest value was (29.11±6.46, 23.00~45.90)mmHg, and the lowest value was (21.34±5.54, 14.00~33.60)mmHg. Although PuvO2 decreased gradually with time (heartbeat) too, most of them also showed the tendency of alternately rising and falling with the regularity of mother's respiration. The mean value of PuvO2 was (53.35±21.35, 32.56~100.73)mmHg, the highest value was (90.38±48.44, 43.40~153.00)mmHg, and the lowest value was (36.96±14.90, 24.80~73.80)mmHg. Although there were large individual differences, the mean, highest and lowest values of PuvO2 were significantly higher than those of PuaO2 (P<0.05); although PuvCO2 slightly lower than PuaCO2, it was no significant difference (P>0.05). Conclusion: PuaO2 decreases gradually with time before spontaneous breathing after the delivered fetus as a newborn, and it induces the first inhalation to start spontaneous breathing when it reaches the threshold of triggering breathing.

[Max test verify further clinical research for whether individualized symptom-limited cardiopulmonary exercise testing is the maximum extreme exercise].

Objective: To verify that the cardiopulmonary exercise testing (CPET) performed by clinical subjects is the maximum extreme exercise, we designed The Max test（Max）during clinical CPET. We used Max to verify the accuracy of the quantitative CPET evaluation result, and whether it is feasible and safe to use the specific value of a certain index as the standard for stopping CPET. Methods: Two hundred and sixteen cases from Fuwai Hospital were selected during June 2017 to January 2019,including 41 healthy person（control group） and 175with cardiovascular diseases（patient group）,The patients had a CPET peak RER ≤ 1.10, or the peak heart rate and peak blood pressure were basically non-responsive.The Max was first attempted in 60 subjects,and this study is further expanded . When the CPET ended, they had a 5-minute break, then the Max, during which, they cycled with a velocity of ≥ 60 r/min, at a constant intensity equivalent to to 130% of peak work,until exhausted.The difference and percentage difference between the peak heart rate and the peak oxygen uptake were calculated. ①If the percentage difference of heart rate and oxygen uptake are all less than -10%,then the Max is defined as failure,otherwise it is succesful. 2 If the percentage difference is between -10%~10%, then the Max is successful, which proved that the CPET is precise.③If the difference is ≥10%, the Max is successful, which proves that the CPET is non-extreme exercise. Results: Patient group's Peak VO2(L/min,ml/(min·kg)),anaerobic threshold (L/min,ml/(min·kg),%pred),Peak VO2/HR(ml/beat, % pred),Peak RER,Peak SBP,Peak WR,peak heart rate,OUEP （ratio,%pred） were lower than those of the control group(P<0.05)．The VE/ VCO2 Slope （ratio,%pred）and Lowest VE/ VCO2（ratio,%pred） were higher in the patient group than in the control group (P<0.05)．No adverse events occurred during the CPET and Max in all cases. Among the 216 cases,Max was successful in 198 cases(91.7%)．CPET was proved to be maximum extreme exercise for 182 cases,non-maximum extreme exercise for 16 cases,and failed in 18 cases(8.3%)．Conclusion: For CPET with a low peak RER and a maximum challenge,the Max can confirm the accuracy of the objective quantitative assessment of CPET. Max is safe and feasible,and that deserved further research and clinical application.

Comparison of acute pneumonia caused by SARS-COV-2 and other respiratory viruses in children: a retrospective multi-center cohort study during COVID-19 outbreak.

BACKGROUND: Until January 18, 2021, coronavirus disease-2019 (COVID-19) has infected more than 93 million individuals and has caused a certain degree of panic. Viral pneumonia caused by common viruses such as respiratory syncytial virus, rhinovirus, human metapneumovirus, human bocavirus, and parainfluenza viruses have been more common in children. However, the incidence of COVID-19 in children was significantly lower than that in adults. The purpose of this study was to describe the clinical manifestations, treatment and outcomes of COVID-19 in children compared with those of other sources of viral pneumonia diagnosed during the COVID-19 outbreak. METHODS: Children with COVID-19 and viral pneumonia admitted to 20 hospitals were enrolled in this retrospective multi-center cohort study. A total of 64 children with COVID-19 were defined as the COVID-19 cohort, of which 40 children who developed pneumonia were defined as the COVID-19 pneumonia cohort. Another 284 children with pneumonia caused by other viruses were defined as the viral pneumonia cohort. The epidemiologic, clinical, and laboratory findings were compared by Kolmogorov-Smirnov test, t-test, Mann-Whitney U test and Contingency table method. Drug usage, immunotherapy, blood transfusion, and need for oxygen support were collected as the treatment indexes. Mortality, intensive care needs and symptomatic duration were collected as the outcome indicators. RESULTS: Compared with the viral pneumonia cohort, children in the COVID-19 cohort were mostly exposed to family members confirmed to have COVID-19 (53/64 vs. 23/284), were of older median age (6.3 vs. 3.2 years), and had a higher proportion of ground-glass opacity (GGO) on computed tomography (18/40 vs. 0/38, P < 0.001). Children in the COVID-19 pneumonia cohort had a lower proportion of severe cases (1/40 vs. 38/284, P = 0.048), and lower cases with high fever (3/40 vs. 167/284, P < 0.001), requiring intensive care (1/40 vs. 32/284, P < 0.047) and with shorter symptomatic duration (median 5 vs. 8 d, P < 0.001). The proportion of cases with evaluated inflammatory indicators, biochemical indicators related to organ or tissue damage, D-dimer and secondary bacterial infection were lower in the COVID-19 pneumonia cohort than those in the viral pneumonia cohort (P < 0.05). No statistical differences were found in the duration of positive PCR results from pharyngeal swabs in 25 children with COVID-19 who received antiviral drugs (lopinavir-ritonavir, ribavirin, and arbidol) as compared with duration in 39 children without antiviral therapy [median 10 vs. 9 d, P = 0.885]. CONCLUSION: The symptoms and severity of COVID-19 pneumonia in children were no more severe than those in children with other viral pneumonia. Lopinavir-ritonavir, ribavirin and arbidol do not shorten the duration of positive PCR results from pharyngeal swabs in children with COVID-19. During the COVID-19 outbreak, attention also must be given to children with infection by other pathogens infection.

[Dendritic cells elicit cellular immune response by targeting to capture breast cancer cells].

OBJECTIVE: To investigate the specific anti-breast cancer immune response induced by dendritic cells (DC) loaded with trastuzumab and apoptotic Her-2+ breast cancer cells. METHODS: DCs were generated from healthy peripheral blood mononuclear cells (PBMCs) in the presence of recombinant cytokines GM-CSF, IL-4 and TNF-alpha. Mature DCs were harvested after 7 days' co-culture of PBMCs and trastuzumab-treated apoptotic SKBr3 cells. The morphologic characteristics and ultrastructure of the DC were observed under the inverted phase-contrast microscope and transmission electron microscope (TEM), respectively. Flow cytometry (FCM) was used to check the expression of several DC specific markers: CD14, CD1a, CD64, CD80, CD83, CD86, HLA-ABC and HLA-DR. DC-cytokine induced killer (DC-CIK) cells were prepared by co-culture of DCs and peripheral blood lymphocytes in the presence of anti-CD3 antibodies and human IL-2 at an appropriate concentration. The number of antigen-specific T cells was analyzed by human interferon gamma enzyme linked immunospot (ELISPOT) assay. MTT assay was employed to assess the lysis of breast cancer cell line induced by DC-CIK cells. RESULTS: 5 minutes after the adding of DCs to SKBr3 cells pretreated with trastuzumab, the apoptotic SKBr3 cells were found to be circled by DCs. 48 hours later, many membrane-wrapped organelles of the apoptotic target cells in the cytoplasm of DCs were found by TEM. The majority of the organelles were degraded. Fewer organelles from the apoptotic cells were found in DCs without Herceptin. More than 60% in every group of DCs expressed a high-affinity receptor for IgG (FcgammaRI or CD64). CD14 expression on the mature DCs were comparatively lower, and HLA-DR and HLA-ABC expressions were higher in the trastuzumab group. The expression of CD1a, CD80, CD83 and CD86 in trastuzumab group were higher than those in immature DCs group (P < 0.05). ELISPOT assay suggests that the spot number of antigen-specific T cells were higher in trastuzumab group than that in the antigen unloaded DCs group (P < 0.05). The lysis of SKBr3 cells induced by the SKBr3 antigen loaded DC-CIK cells were 1.7 times higher than that of CIK. CONCLUSION: The lysis of SKBr3 cells induced by DC-CIK was increased after that DCs were combined with trastuzumab to capture antigen from SKBr3 cells. These findings support further investigation into the use of combination immunotherapy of the humanized monoclonal antibody, DC vaccines and immunological effector cells.

[Detection and classification of Mycoplasma in cell lines].

OBJECTIVE: To detect the rate of Mycoplasma infection in cell lines and further determine its types. METHODS: We performed nest PCR amplification of Mycoplasma's conserved regions (16S-23S) and sequenced the spacer with different length between conserved regions. RESULTS: Within the tested 22 cell lines, 17 (77.3%) showed Mycoplasma infections, of which 5 had two or more types of Mycoplasma. M. fermentans and hyorhinis were more frequently detected within the types of infected Mycoplasma. CONCLUSION: The high rate of Mycoplasma infection in cell lines makes it necessary for researchers to pay more attention to its influence on research data when using cell lines as models. Establishment of detection and classifying techniques make it possible to further study the pathogenesis of different types of Mycoplasma.

[Cytokine-induced killer cells induce apoptosis of K562 cells expressed bcr-abl].

In order to investigate whether cytokine-induced killer (CIK) cells can induce apoptosis of bcr-abl(+) K562 cells, apoptosis of K562 cells and CEM cells induced by CIK cells, etoposide or camptothecin was detected with flow cytometry DNA assay. RT-PCR showed that K562 cells expressed the bcr-abl fusion gene, K 562 cells, K562 cells/etoposide or K562 cells/camptothecin groups showed no sub-G(1) peak. K562 cells/CIK cells group showed sub-G(1) peak (38.1%). CEM cells showed no sub-G(1) peak. CEM cells/camptothecin or CEM cells/etoposide groups showed sub-G(1) peak (23.5% or 32.3% respectively). CEM cells/CIK cells group showed sub-G(1) peak (45.4%). Etoposide or camptothecin did not induce apoptosis of K562 cells. CIK cells induce apoptosis of K562 cells. Bcr-abl fusion gene prevented apoptosis induced by etoposide or camptothecin, but did not prevent apoptosis induced by CIK cells. This property may support the observed adoptive immunologic effect of allogeneic bone marrow transplantation and donor lymphocyte transfusions of CML case relapsing after allogeneic bone marrow transplantation.