APG system

Abstract: Objects We have recently developed a new type of acceleration plethysmography (APG) machine and software. This APG system functions to indicate heart rate variability, by using the coefficient of the variation of the a-a intervals (CVaa%) . We tried to evaluate the validity of the APG system to estimate heart rate variability, instead of using ECG.Methods We simultaneously recorded an ECG and an APG by using a 2-channel APG system. We examined the difference between the a-a intervals (Taa) of an APG and the R-R interval of an ECG. Next, APG waveforms of 121 healthy people and 26 diabetics were recorded, and the mean CVaa% in each age category for healthy people and diabetics were calculated.Results 1) All differences between the Taa and the R-R interval were within 10 msec., and the multiple correlation coefficient was 0.999175.2) The mean CVaa% was 0.2 to 1.5% bigger than the mean coefficient of the variation of the R-R intervals (CVRR%) in all age categories. 3) The mean CVaa% decreased by age. 4) In ages 40-60, mean CVaa% of diabetics was significantly lower than that of healthy people.Conclusion The APG system is suitable to estimate heart rate variability. And, when we want to evaluate heart rate variability by CVaa% of an APG in stead of CVRR% of an ECG, a standard value of CVaa% in each age is necessary. The APG system has some possibilities for explanation of a mechanism of autonomic-nerve-related diseases.

Abstract: It is commonly known that autonomic modulations are caused by depression, fatal arrhythmia, and vascular disease. This may lead to be an urgent need of a reliable physiological technology to evaluate autonomic modulations. The specific purpose of the current study is to examine the possibility of whether the Acceleration Plethysmography (APG) system can become a new useful tool to measure autonomic modulations. We verified the heart rate variability (HRV) analysis by APG whether it can be used as same as by the ECG. The HRV is interpreted from the a-a interval (Taa) on APG waves. We assembled the simultaneous measurement system of APG and ECG, examined the identities of the R-R interval (TRR) of ECG and the Taa of APG in six subjects of 22-60 old, and then compared variables in frequency domains of HRV by both APG and ECG. The results showed a close correspondence of the Taa and the TRR. Furthermore, when the regression formula was set as Taa=C*TRR, the coefficient of regression (C) was 1.0002, 1.0001, 0.9997, 1.0000, 0.9999, 1.0001 respectively; whereas for each subject, the coefficient of determination was 0.9901, 0.9892, 0.9968, 0.9740, 0.9676, 0.9677 respectively (p<0.01) . As for the difference between APG and ECG, the coefficient of variation of HRV was merely 0.1-0.2%, and the LF/HF ratio as 0.1-0.4. If we carefully interpret the results of the frequency analysis, the APG system can be a useful objective methodology to evaluate autonomic modulations. Because of its simplicity in usage, it is expected to be employed in the occupational health or primary care.

Abstract: Phylogenctic position of the monotypic genus Dipentodon has long been controversial. We investigated its,:position with 125 accessions representing 50 genera and 40 families of eudicots in the APG system. Four data sets-including the chloroplast gene rbcL, the nuclear 18S ribosomal DNA, and the mitochondrial gene matR, as well as,,,the combined matrix-were used in the study with the maximum parsimony (MP) and Bayesian inference (131) analyses. The phylogenctic trees based on individual genes and the combined data suggested that Diventodon is sister to Tapiscia (Tapisciaceae) and that Dipentodon could be placed in euroside 11 of the APG system. The clade of Dipentodon and Tapiscia is closest to Malvales and Sapindales. Such finding does not support the previously suggested close relationship between Dipentodon and various other groups, including Celastraceae, Samydaceae, Flacourtiaceae, Hamamelidaceae, and Santalales.