But so far, improvement in vision has persisted as long as two years after a single treatment without evidence of significant adverse side effects.

但到目前为止，在经过一次性治疗后，病人视觉的改善最长已经维持了两年时间，没有证据显示出现了明显的不良副作用。

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Between 2001 and 2003, the patients received up to three perfusions of islet cells, so long as islet function persisted after the preceding transplantation.

在2001年到2003年之间，胰岛功能在前一次移植后能够维持的患者接受了多达3次的胰岛细胞移植。

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