Improved amplification efficiency on stool samples by addition of spermidine and its use for non-invasive detection of colorectal cancer

Table 1 PCR efficiencies in presence and absence of spermidine

1st experiment	Sperm.	Ct	∆Ct	AE (%)	Effects ?
1st serial
Control	0	20.05 ± 0.17		100
	1	20.11 ± 0.02	0.06	96	=
	2	20.77 ± 0.17	0.72	61	-
	3	21.12 ± 0.03	1.07	48	-
	4	21.70 ± 0.32	1.65	32	-
	5	22.66 ± 0.16	2.61	16	-
	10	NA	ND	0	Total inhibition
Sample	0	28.16 ± 0.85		100
	1	25.11 ± 0.11	−3.06	831	+
	2	25.35 ± 0.03	−2.81	701	+
	3	25.73 ± 0.11	−2.44	541	+
	4	26.53 ± 0.16	−1.63	310	+
	5	28.08 ± 0.13	−0.08	106	+
	10	NA	ND	0	Total inhibition
2nd serial
Control	0	19.86 ± 0.33		100
	0.05	19.61 ± 0.10	−0.25	119	+
	0.10	19.78 ± 0.13	−0.09	106	+
	0.50	19.87 ± 0.15	0	100	=
	1	19.91 ± 0.14	0.05	97	=
Sample	0	28.17 ± 0.26		100
	0.05	26.63 ± 0.49	−1.54	290	+
	0.10	25.98 ± 0.11	−2.19	456	+
	0.50	25.09 ± 0.01	−3.08	843	+
	1	25.22 ± 0.11	−2.95	773	+

Abbreviations: Sperm., spermidine (mM); Ct, mean of cycle threshold value ± standard deviation value; AE, amplification efficiency; NA, non amplification; ND, not determined; =, equal; −, inhibitor; +, facilitator.
The amplification efficiency of the albumin gene at each spermidine concentration points was calculated using 2^-ΔCt where ΔCt = (Ct _{with spermidine}) – (Ct _{without spermidine}). For example in the 1st study, Control DNA with 1 mM of spermidine showing a ΔCt = 0.06, we recovered 96% of the true yield (100%, ΔCt = 0).

ISSN: 1472-6750