Effect of HALI and di-h-HALI on the number of fenestrae per micrometer squared in time. From this graph, we can conclude that both agents increase the number of fenestrae, although at a different rate and different maximum. Data are means plus or minus S.E.M. of triplicate determinations. Note the significant differences between control LSECs (0 minutes) and treated LSECs, as indicated by asterisks (p < 0.01) or by triangles (p < 0.05) (Mann-Whitney U test, two-sided). No significant difference in the number of fenestrae was observed at the 0.05 confidence level between 60 and 120 minutes of treatment with HALI or di-h-HALI.