West C M, Moore J V
Photochem Photobiol. 1989 Nov;50(5):665-9. doi: 10.1111/j.1751-1097.1989.tb04324.x.
Flow cytometry (FCM) has been used to investigate the intracellular fluorescence of hematoporphyrin derivative (HPD) in monolayer and spheroid cultures of WiDr cells. For exponentially-growing monolayer cultures mean cellular fluorescence was directly proportion to the external HPD levels in the range 5-100 micrograms ml-1 (r = 0.99). Heterogeneity of cellular fluorescence was quantified by determining the ratio of the fluorescence value below which were observed values for 98% of the cell population compared to the fluorescence value for 2%. In exponentially-growing cultures, decreasing levels of HPD in the medium led to an increase in the 98:2% ratio, i.e. an increase in heterogeneity of intracellular drug levels. The growth of cells as multicellular spheroids confers a spheroid-size-dependent resistance to photodynamic treatment. With increasing spheroid size (100, 250, 500, 750 and 1000 microns diam.) there was a decrease in mean intracellular HPD levels and a large linear increase in the 98:2% ratio (r = 0.94).
流式细胞术（FCM）已被用于研究维氏大鼠十二指肠腺癌细胞（WiDr细胞）单层培养和球体培养中血卟啉衍生物（HPD）的细胞内荧光。对于指数生长的单层培养物，平均细胞荧光与5-100微克/毫升范围内的外部HPD水平直接成正比（r = 0.99）。通过确定荧光值的比率来量化细胞荧光的异质性，该比率是指在该荧光值以下观察到98%细胞群体的荧光值与2%细胞群体的荧光值之比。在指数生长的培养物中，培养基中HPD水平的降低导致98:2%比率增加，即细胞内药物水平的异质性增加。细胞作为多细胞球体生长赋予了对光动力治疗的球体大小依赖性抗性。随着球体大小增加（直径为100、250、500、750和1000微米），平均细胞内HPD水平降低，98:2%比率大幅线性增加（r = 0.94）。
