{'fraction_non_alphanumeric': 0.01902587519025875, 'fraction_numerical': 0.00989345509893455, 'mean_word_length': 5.059907834101383, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Human embryonic stem cells: hype or hope?

Embryonic stem (ES) cells have emerged in recent years as powerful tools for the study of in vitro and in vivo development. The engineering of mouse ES cells has been the basis of major advances in mouse transgenesis and subsequent breakthrough findings pertaining to many aspects of development and disease (31) as well as therapeutic targeting (47). Similarly, the recent derivation of human ES (hES) cells (40,46) has generated significant interest in the scientific as well as the lay community, especially in view of their potential as a universal cell source for cell replacement therapies. These efforts have also kindled complex ethical and political debate centered over the moral implications of the blastocyst derivation of ES cells and the arguable obligations to seek therapies that stand to alleviate human suffering. Current federal policy limits funding of hES cell research to work involving a small group of ES lines derived before August 9, 2001 and listed in a National Institutes of Health registry. Funding of somatic nuclear transfer for the derivation of cloned ES cells is also prohibited. The purpose of this brief review is to present recent advances in human ES cell research with special emphasis on central nervous system (CNS) applications.