Buy an essay on Statistical analysis of cues causing dive reflex and effects of changes caused by Drug

The aim of this research is to study human dive reflex via measuring heart rate, and analyze the cues simulating the dive response basing on the following measurements of heart rate: resting, simulated dive, breath hold in air, snorkel + dive, snorkel in air, cold gel pack applied when breathing, cold gel pack applied while holding breath, RT gel pack when breathing, RT gel pack while holding breath. For this task it is reasonable to use ANOVA (repeated measures analysis) with resting heart rate measurement and simulated dive chosen as groups to be compared with other groups (Bonferroni post test, comparison of column A versus all other columns and column B versus all other columns selected). Significance level was defined as p<0.05 (p<0.01 will be considered as very significant and denoted by **, p<0.001 will be considered as extremely significant and denoted as ***).

Fig. 1 represents results of comparing means of heart rate while resting to other groups. Fig. 2. shows the comparison of groups C-I (starting from breath hold in air to RT gel pack/breathing).

Figure 1: Comparison of heart rate measurement compared to resting

(statistical significance, i.e. p<0.001, denoted by ***)

Figure 2: Comparison of heart rate measurement compared to simulated dive

(statistical significance: p<0.01, denoted by **, p<0.001 denoted as ***)

As it can be concluded from Fig. 1, comparison of resting heart rate measurement to other groups showed statistically significant difference of the means for simulated dive (i.e. the existence of simulated dive effect was proven), for snorkeling while diving, and for applying cold pack both when breathing and when breath is hold. Thus, it can be concluded that cold temperature is one of the cues simulating dive reflex.

Fig. 2 gives more information on these cues: statistical difference of mean heart rate during simulated dive and when breath was hold in air was shown; also, extremely significant difference occurs for snorkeling in air, and application of RT gel pack while breathing, and while breath is hold. Medium significance was shown for application of cold gel pack when breath is hold. Thus, it is possible to state that dive reflex is also caused by such cues as water submersion and breath holding.

Data Set 2.

The aim of this research is to study the effect of drug X on the level of reactive oxygen species (via measuring DCF fluorescence) and on caspace-3 activity. Analysis of different concentrations of Drug X on DCF fluorescence and caspace-3 activity was performed using ordinary ANOVA, suggesting that all values were sampled from Gaussian distribution. P-value of the whole data set is <0.0001, considered extremely significant.

Concentration of 0 uM was taken as control group, and post-tests were made by comparing all groups versus control group – Dunnett post test. Significance level chosen – p<0.05. Fig. 3. illustrates groups where the difference between means is statistically significant. It is possible to determine that concentration of drug X of 0.4uM and more results in statistically significant difference of the means, and thus proven the effect of this drug, when concentration is greater than 0.4uM. Linear regression analysis (R²=0.958) shows that there is strong relationship between mean DCF fluorescence and drug X concentration.

Figure 3: Comparison of means for different drug X concentration

(statistical significance, i.e. p<0.05, denoted by *)

Fig. 4 illustrates the results of statistical analysis of drug X impact on caspace-3 activity (different concentrations of drug X compared as in previous example). Analysis was done using ordinary ANOVA, with Dunnett post-test. P-value of the whole data set is <0.0001; thus, drug X has an effect on caspace-3 activity. ANOVA shows that all concentrations but 0.1uM has a statistically different mean from control group, and thus, drug X has effect for concentration greater than 0.1 uM (0.1, 0.2, 0.4, 2, 5 uM). Linear regression analysis (R²=0.962) shows that there is strong relationship between mean caspace-3 acrivity and drug X concentration.

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Figure 4: Comparison of means for different drug X concentration

(statistical significance, i.e. p<0.05, denoted by *)

In order to determine whether there is an association between changes in ROS and changes in caspace-3 activity, correlation analysis (Pearson r, suggesting Gaussian distribution) of two caspace-3 activity measurements (5 um drug X only and 5 uM drug X + 250 uM NAC) was performed. Correlation coefficient value r = -0.1911, and r squared is 0.03562. Two-tailed p-value for r² is 0.7582; thus, r is not significantly different from zero. Thus, it is possible to state that there is no correlation between caspace-3 activity using NAC and without NAC. Fig. 5. illustrates comparison of the effect of drug X alone to drug X effect plus NAC.

Figure 5: Comparison of drug X effect to Drug X + NAC on caspace-3 activity (no statistical significance found)

Thus, statistical analysis shows that drug X has effect both on ROS changes (starting from concentration of 0.4 uM) and on caspace-3 activity (starting from concentration of 0.2 uM). Also, it has been found that ROS changes do not affect caspace-3 activity significantly; consequently, measured changes in caspace-3 activity are the effect of drug X – which proves its efficiency for the above-mentioned concentrations.