The anastomosis angle does change the flow fields at vascular end-to-side anastomoses in vivo.

No abstract

Summary Cell survival was investigated in an intraocular retinoblastoma-like tumour 30min to 48h after photodynamic therapy. The survival of the cells was assessed by an in vivo to in vitro colony forming assay, estimated by either the plating efficiency of the treated tumour cells compared to non-treated cells or the number of clonogenic cells per mg excised tumour. Curves showing cell survival as a function of the time between light irradiation and excision of the intraocular tumours were biphasic. This suggests more than one PDT tissue destruction mechanism in vivo (i.e. an early direct cell damage plus a subsequent late damage occurring in the tumour tissue left in situ after treatment). The delayed mechanism may be due to changes in the environment of the tumours probably caused by vascular damage. Tumour cells sensitised by Photofrin II in vivo and excised from the eyes were damaged by light when irradiated in vitro and this was dependent on the light energy dose. This showed that cellular Photofrin II uptake in the eye tumours was sufficient for direct cell damage and thus supports the suggestion that direct and indirect tumour destruction occurs in this eye tumour after photodynamic therapy.

We report the amplification of the putative oncogene INTl in two of four retinoblastomas. In one case, the INTl signal was amplified 10 to 15-fold, in the other 100-fold. In both cases there were signs of increased tumor aggressiveness with invasion of the choroid and development of metastases. The two cases without INTl amplification had neither metastases nor locally invasive growth. Our findings indicate that INTl amplification may be a feature of increased malignant potential in retinoblastomas.

Retinoblastoma-like cells grew in colonies on the bottom of tissue culture flasks. The population doubling time was 19 h. Tumour cells from cell cultures had a 39% plating efficiency, and fresh tumour cells from intraocular tumours had a 32% plating efficiency in colony forming assays. Inoculation of 1.5 X 10(4) tumour cells in the vitreous of F-344 rats resulted in a 100% tumour take and regularly growing tumours with a doubling time of 3 days. The tumour take-rate was not changed in wholebody immunosuppressed animals. The tumour volume was assessed under a stereo microscope, and it was possible to divide the tumours into 4 groups according to the number of intraocular tumour cells. Tumour growth caused eye perforation in 89% of the inoculated eyes. Spontaneous tumour regression was not seen in non-perforation groups. Immunosuppression with whole-body irradiation and dense traumatic cataract had no significant effect on the growth. It is concluded that this animal retinoblastoma-like tumour is suitable for quantitative therapy studies in vivo and in vitro.