ABSTRACT
Objective To compare the discrepancies among results of three commonly used laboratory direct test methods for maximal oxygen uptake(VO2max),explore their linear regression relationships,mutual predictability and comparability.Methods Using a quasi-experimental design of cluster sampling and within-group interaction design,20 male cross-country skiers were tested for VO2max using the Bruce protocol(Method 1),90-second incremental load exercise on power bicycle(Method 2),and 1-minute incremental load exercise on treadmill(Method 3),with an interval of one week.The indepen-dent and dependent variable were the three VO2max test methods and the VO2max,respectively.Results Significant differences were found in the average VO2max of the three test results,with the value mea-sured by Method 1 ranking the first,followed by that assessed by Method 3 and Method 2(P<0.05).Moreover,the frequency of individual differences in the results of the three methods showed that the VO2max of Method 1 was about 6 and 3 ml/min·kg higher than that measured by Method 2 and 3.However,at the same treadmill speed,the average blood lactate evaluated using Method 3 was higher than Method 1,and the speed reached aerobic and anaerobic thresholds about one speed unit(1 km/h)lower than Method 1.Meanwhile,linear regression analyses of the test results between Method 1 and 2,as well as Method 1 and 3 showed that both the regression models and coefficients were statis-tically significant(P<0.001),with the R-squared values of 9.25 and 9.05,respectively.Conclusion The Bruce protocol performs best in assessing the maximum value of the athlete's VO2max phase,whose results have linear regression relationships with the other two methods,and can be used for pre-dicting their results.Moreover,athletes of different events and levels can choose different VO2max test methods accordingly.Lastly,the speed and heart rate ranges corresponding to the aerobic and anaero-bic thresholds can serve as an effective and convenient method to control the training intensity.
ABSTRACT
Objective To compare dose distribution in gamma knife radiotherapy plan, conformal radiotherapy(CRT)plan and intensity modulated radiotherapy(MRT)plan for patients with small mass in lung, and evaluate their characters. Methods Fourteen patients with small mass in lung participated in the study. Gamma knife radiotherapy plan(plan 1), CRT plan(plan 2)and IMRT plan(plan 3)were made for each mass. The planning target volume(PTV)and the dose include 95% PTV were consistent.Conformal index(CI), homogeneity index(HI), lung V5 ,V10 ,V20 ,V30 and the max dose of esophagus and spinal cord were analyzed. Paired samples t-test was used for comparison between each two plans. Results The CI of the plan 1,2 and 3 were 0. 58,0. 46 and 0. 63, respectively. CI of the plan 1 ＞ that of the plan 2 (t= -3.95,P =0.000),plan 3 ＞ plan 2(t = -6.01 ,P =0.000),plan 1 =plan 3(t =1.64,P =0.116);HI of the plan 1,2 and 3 were 1.66,1.10 and 1.07 respectively. HI of the plan 1 ＞ plan 2 ,plan 1 ＞ plan 3(t= -20.52,21.41 respectively, both P=0. 000),plan 2 = plan 3(t= -1.08,P=0.294). The wholelung V5 ,V10 ,V20 and V30 were 10.0% ,5.6% ,2. 4% and 1.2%, respectively, in plan 1 ;20. 2% ,13. 4%,6. 9% ,3.0%, respectively, in plan 3; and 26. 5%, 18. 0%, 11.4% and 4. 6%, respectively, in plan 2.The V5, V10, V20 and V 30 of the plan 1 ＜ in plan 2(t = 9. 68,8. 41,5. 45,5. 14, all P = 0. 000), the V5,V10,V20 and V30 of the plan 1 ＜ in plan 3(t=7.58,8.95,6. 15,4.78, respectively, all P=0.000),the V5 ,V10, V20andV30 oftheplan2 ＞ inplan3(t =9. 71,5. 91,4. 13,3.91, respectively, allP =0.000).The max dose of esophagus in plan 1 ,2 and 3 were 24.93 ± 21.54, 31.90 ± 18. 75, 29. 19 ± 23.09 Gy,respectively, plan 1 ＜ plan 2(t = -2. 71 ,P=0.013),plan 1 = plan 3(t = - 1.49,P =0. 152),plan 2 =plan 3(t = 1.35, P = 0. 193). The max dose of spinal cord in plan 1,2 and 3 were 12.07 ± 10. 67,17.70 ±11.35 and 8.92 :± 10. 04 Gy, respectively, plan 2 ＞ plan 1 ＞plan 3(t = -2. 38,2. 29,4. 83,P=0. 1027,0.033,0.000);All three plans of each mass meet the needs that the max dose of the esophagus≤60 Gy and the max dose of spinal cord ≤40 Gy. Conclusions The dose of the normal lung was lower, but the HI and the max dose of spinal cord were higher in Gamma knife radiotherapy plan than those in the CRT and the IMRT plan of the small mass in lung.
ABSTRACT
The relationship between 5-HT receptor and a-adrenoceptor was investigated in rat medullary slice preparations. In 57 nucleus tractus solitarii (NTS) neurons, 47 (82.5%) responded to both serotonin (5-HT) and norepinephrine (NE). After synapse transmission was blocked by perfusion of artificial cerebrospinal fluid (ACSF) with low calcium and high magnesium, 5 in 8 neurons were still sensitive to both 5-HT and NE. On the other hand, 3 in 5 neurons responding only to 5-HT or NA were sensitive to both 5-HT and NE after the synapse transmission blockage. In some neurons which exhibited excitatory or inhibitory responses to 5-HT or NE alone, the responses were inversed when perfused with 5-HT and NE in combination. These results suggest that there may exist an inhibitory interaction between 5-HT receptors and a-adrenoceptors in NTS and that most 5-NT and a-adrenoceptors coexist in the same NTS neurons.