The sciatic nerves of rabbit were frozen with different temperatures(-20℃,-60℃, -- 100℃, -140℃ and 180℃).The morphology and function of the frozen nerves were examined with light microscopy (HE stain and histochemical thiocholism method), electron microscopy, and short latency sematesthelic evoked potentials(SSEP), sensory conduction velocity(SCV), electromyo-gram(EMG) at various time intervals after freezing. It was showed that there were no changes in morphology and function of nerves after being frozen at -20C. The nerve fibers showed signs of frozen degeneration and lost their conduction function at -60℃. However, the nerves could recover in this group. About one half of the nerve fibres frozen with -100℃ showed Wallerian degeneration, and the time of repair was delayed. But still the regeneration of nerves was complete. Necrosis of nerve fibers occurred immediately after freezing with -140℃ and-180℃. There were destruction of the basement membrane and proliferation of collagen fibers. The results explained the mechanism of cryoanalgesia clinically. We believe that the temperatures lower than -140℃ are optimal for cryoanalgesia.

Objective To observe the effect of different airway pressure on ventilation, organ perfusion and return of spontaneous circulation (ROSC) of cardiac arrest (CA) pigs during cardiopulmonary resuscitation (CPR), and to explore the possible beneficial mechanism of positive airway pressure during CPR. Methods Twenty healthy landrace pigs of clean grade were divided into low airway pressure group (LP group, n = 10) and high airway pressure group (HP group, n = 10) with random number table. The model of ventricular fibrillation (VF) was reproduced by electrical stimulation, and mechanical chest compressions and mechanical ventilation (volume-controlled mode, tidal volume 7 mL/kg, frequency 10 times/min) were performed after 8 minutes of untreated VF. Positive end expiratory pressure (PEEP) in LP group and HP group was set to 0 cmH2O and 6 cmH2O (1 cmH2O = 0.098 kPa) respectively. Up to three times of 100 J biphasic defibrillation was delivered after 10 minutes of CPR. The ROSC of animals were observed, and the respiratory parameters, arterial and venous blood gas and hemodynamic parameters were recorded at baseline, 5 minutes and 10 minutes of CPR. Results The number of animals with ROSC in the HP group was significantly more than that in the LP group (8 vs. 3, P < 0.05). Intrathoracic pressure during chest compression relaxation was negative in the HP group, and its absolute value was significantly lower than that in LP group at the same time [intrathoracic negative pressure peak (cmH2O): -4.7±2.2 vs. -10.8±3.5 at 5 minutes, -3.9±2.8 vs. -6.5±3.4 at 10 minutes], however, there was significantly difference only at 5 minutes of CPR (P < 0.01). Intrathoracic pressure variation during CPR period in the HP group were significantly higher than those in the LP group (cmH2O: 22.5±7.9 vs. 14.2±4.4 at 5 minutes, 23.1±6.4 vs. 12.9±5.1 at 10 minutes, both P < 0.01). Compared to the LP group, arterial partial pressure of oxygen [PaO2 (mmHg, 1 mmHg = 0.133 kPa): 81.5±10.7 vs. 68.0±12.1], venous oxygen saturation (SvO2: 0.493±0.109 vs. 0.394±0.061) at 5 minutes of CPR, and PaO2 (mmHg: 77.5±13.4 vs. 63.3±10.5), arterial pH (7.28±0.09 vs 7.23±0.11), SvO2 (0.458±0.096 vs. 0.352±0.078), aortic blood pressure [AoP (mmHg): 39.7±9.5 vs. 34.0±6.9], coronary perfusion pressure [CPP (mmHg): 25.2±9.6 vs. 19.0±7.6], and carotid artery flow (mL/min:44±16 vs. 37±14) at 10 minutes of CPR in the HP group were significantly higher (all P < 0.05). Arterial partial pressure of carbon dioxide (PaCO2) in the HP group was significantly lower than that in the LP group at 10 minutes of CPR (mmHg: 60.1±9.7 vs. 67.8±8.6, P < 0.05). Conclusions Compared to low airway pressure, a certain degree of positive airway pressure can still maintain the negative intrathoracic pressure during relaxation of chest compressions of CPR, while increase the degree of intrathoracic pressure variation. Positive airway pressure can improve oxygenation and hemodynamics during CPR, and is helpful to ROSC.

OBJECTIVETo provide the basis for improving utilization of Artemisia annua germplasm resources and breeding variety, the interrelations between artemisinin content, artemisinin yield and agronomic traits of A. annua were studied.

METHODThe artemisinin content and each agronomic trait of 63 A. annua germplasm resources were measured by the visual observation and measurement methods. And the correlation analysis, regression analysis and path analysis were adopted.

RESULTThe result showed that there were significant differences in the artemisinin content and yield of 63 germplasm resources from the main production region of A. annua. Correlation analysis showed that there were significantly positive correlation between leaf weight and artemisinin yield with stem and branch characters, but there were negative correlation between artemisinin content with leaf characters of A. annua plant. The artemisinin content of A. annua increased with the increasing of primary branch number, bottom secondary branch number, and bottom stem diameter, etc. On the other hand, it decreased with the increasing of top secondary branch number, secondary leaf axis length, and bottom branch diameter, etc. The artemisinin yield of A. annua increased with the increasing of artemisinin content, leaf weight, and bottom secondary branch number, etc., and decreased with the increasing of bottom branch diameter, middle secondary branch number, and stem weight, etc. Path analysis showed that the primary branch number and bottom secondary branch number had a direct positive effect on the artemisinin content of A. annua. But the top secondary branch number had a direct negative effect on the artemisinin content of A. annua. The leaf weight and artemisinin content had a direct positive effect on the artemisinin yield and the ratio of leaf/stem, branch weight and stem weight had a direct negative effect.

CONCLUSIONOn the breeding A. annua variety, it can take into account both high leaf yield and high artemisinin content. And it was strongly recommend that the plant with moderate plant height and crown, shortness pinnae and secondary leaf axis, less middle and top secondary branch, strong stem, higher primary branch number and bottom secondary branch number, and higher ratio leaf/stem could be selected for breeding new varieties with high leaf yield and high artemisinin content.

Artemisia annua ; chemistry ; growth & development ; Artemisinins ; analysis ; Biomass ; Plant Extracts ; analysis ; Plant Leaves ; chemistry ; growth & development ; Plant Stems ; chemistry ; growth & development

Objective To approach the predictive value of continuous monitoring end-tidal carbon dioxide partial pressure (PETCO2) on the outcome of in-hospital cardiopulmonary resuscitation (CPR), and explored the indicators of termination of resuscitation. Methods A secondary analysis of a multicenter observational study data was conducted. The screening aim was adult non-traumatic in-hospital CPR patients whose PETCO2were recorded within 30 minutes of CPR. Clinical information was reviewed. The mean PETCO2in restoration of spontaneous circulation (ROSC) and non-ROSC patients was recorded. The outcome of CPR was continuously assessed by PETCO2≤ 10 mmHg (1 mmHg = 0.133 kPa) for 1, 3, 5, 8, 10 minutes. Receiver operating characteristic (ROC) curve was plotted, and the predictive value of PETCO2≤ 10 mmHg for different duration on the outcome of CPR was evaluated. Results A total of 467 recovery patients, including 419 patients with complete recovery were screened. Patients who were out-of-hospital resuscitation, non-adults, traumatic injury, had no PETCO2value, PETCO2value failed to explained the clinical conditions, or patients had not monitored PETCO2within 30 minutes of resuscitation were excluded, and finally 120 adult patients with non-traumatic in-hospital resuscitation were enrolled in the analysis. The mean PETCO2in 50 patients with ROSC was significantly higher than that of 70 non-ROSC patients [mmHg: 17 (11, 27) vs. 9 (6, 16), P < 0.01]. ROC curve analysis showed that the area under ROC curve (AUC) of PETCO2during the resuscitation for predicting recovery outcome was 0.712 [95% confidence interval (95%CI) = 0.689-0.735]; when the cut-off was 10.5 mmHg, the sensitivity was 57.8%, and the specificity was 78.0%, the positive predictive value (PPV) was 84.6%, and negative predictive value (NPV) was 46.9%. The duration of PETCO2≤ 10 mmHg was used for further analysis, which showed that with PETCO2≤10 mmHg in duration, the prediction of the sensitivity of the patients failed to recover decreased from 58.2% to 28.2%, but specificity increased from 39.4% to 100%; PPV increased from 40% to 100%, and NPV decreased from 57.5% to 34.2%. Conclusion For adult non-traumatic in-hospital CPR patients, continuous 10 minutes PETCO2≤10 mmHg may be an indicate of termination of CPR.

OBJECTIVETo study the accuracy of pulse contour cardiac output (PCCO) during blood volume change.

METHODSHemorrhagic shock model was made in twenty dogs followed by volume resuscitation. Two PiCCO catheters were placed into each model to monitor the cardiac output (CO). One of catheters was used to calibrate CO by transpulmonary thermodilution technique (COTP) (calibration group), and the other one was used to calibrate PCCO (none-calibration group). In the hemorrhage phase, calibration was carried out each time when the blood volume dropped by 5 percents in the calibration group until the hemorrhage volume reached to 40 percent of the basic blood volume. Continuous monitor was done in the none-calibration group.Volume resuscitation phase started after re-calibration in the two groups. Calibration was carried out each time when the blood equivalent rose by 5 percents in calibration group until the percentage of blood equivalent volume returned back to 100. Continuous monitor was done in none-calibration group. COTP, PCCO, mean arterial pressure (MAP), systemic circulation resistance (SVR), global enddiastolic volume (GEDV) were recorded respectively in each time point.

RESULTS(1) At the baseline, COTP in calibration group showed no statistic difference compared with PCCO in none-calibration group (P >0.05). (2) In the hemorrhage phase, COTP and GEDV in calibration group decreased gradually, and reached to the minimum value (1.06 ± 0.57) L/min, (238 ± 93) ml respectively at TH8. SVR in calibration group increased gradually, and reached to the maximum value (5 074 ± 2 342) dyn · s · cm⁻⁵ at TH6. However, PCCO and SVR in none-calibration group decreased in a fluctuating manner, and reached to the minimum value (2.42 ± 1.37) L/min, (2 285 ± 1 033) dyn · s · cm⁻⁵ respectively at TH8. COTP in the calibration group showed a significant statistic difference compared with PCCO in the none-calibration group at each time point (At TH1-8, t values were respectively -5.218, -5.495, -4.639, -6.588, -6.029, -5.510, -5.763 and -5.755, all P < 0.01). From TH1 to TH8, the difference in percentage increased gradually. There were statistic differences in SVR at each time point between the two groups (At TH1 and TH4, t values were respectively 2.866 and 2.429, both P < 0.05, at TH2 - TH3 and TH5 - TH8, t values were respectively 3.073, 3.590, 6.847, 8.425, 6.910 and 8.799, all P < 0.01). There was no statistic difference in MAP between the two groups (P > 0.05). (3) In the volume resuscitation phase, COTP and GEDV in the calibration group increased gradually. GEDV reached to the maximum value ((394±133) ml) at TR7, and COTP reached to the maximum value (3.15 ± 1.42) L/min at TR8. SVR in the calibration group decreased gradually, and reached to the minimum value (3 284 ± 1 271) dyn · s · cm⁻⁵ at TR8. However, PCCO and SVR in the none-calibration group increased in a fluctuating manner. SVR reached to the maximum value (8 589 ± 4 771) dyn · s · cm⁻⁵ at TR7, and PCCO reached to the maximum value (1.35 ± 0.70) L/min at TR8. COTP in the calibration group showed a significant statistic difference compared with PCCO in the none-calibration group at each time point (At TR1-8, t values were respectively 8.195, 8.703, 7.903, 8.266, 9.600, 8.340, 8.938, 8.332, all P < 0.01). From TR1 to TR8, the difference in percentage increased gradually. There were statistic differences in SVR at each time point between the two groups (At TR1, t value was -2.810, P < 0.05, at TR2-8, t values were respectively -6.026, -6.026, -5.375, -6.008, -5.406, -5.613 and -5.609, all P < 0.05). There was no statistic difference in MAP between the two groups (P > 0.05).

CONCLUSIONPCCO could not reflect the real CO in case of rapid blood volume change, which resulting in the misjudgment of patient's condition. In clinical practice, more frequent calibrations should be done to maintain the accuracy of PCCO in rapid blood volume change cases.

Animals ; Blood Volume ; Calibration ; Cardiac Output ; Disease Models, Animal ; Dogs ; Humans ; Monitoring, Physiologic ; Shock, Hemorrhagic ; diagnosis ; Thermodilution