TABLE 3.

Time-dependent changes in the activity and number of NK cells in blood^a

Parameter and groupb	8 wk before the exam	2 wk before the exam	1 day before the exam	Immediately after the exam	2 wk after the exam
NK cell activity (%)
Placebo	19.8 ± 1.5	23.9 ± 1.9	19.3 ± 1.3	13.8 ± 1.3c	17.6 ± 1.4
L. casei strain Shirota	20.9 ± 2.1	26.0 ± 2.4	18.5 ± 1.9	15.7 ± 1.5	17.7 ± 1.7
NK cell no. (cells/ml)
Placebo	17.1 ± 1.1	13.0 ± 1.2c	14.2 ± 1.1	10.2 ± 0.9d	11.9 ± 1.0d
L. casei strain Shirota	17.7 ± 1.3	16.8 ± 1.4	16.3 ± 1.5	11.2 ± 0.9d	13.1 ± 1.0

^aValues indicate means ± SE. Data were analyzed by Dunnett's multiple-comparison test within a group and the unpaired Student's t test between the groups.

^bPlacebo group, n = 24; L. casei strain Shirota group, n = 23.

^cP < 0.05.

^dP < 0.01 vs. baseline (8 weeks before).