{'fraction_non_alphanumeric': 0.013417521704814523, 'fraction_numerical': 0.009471191791633781, 'mean_word_length': 5.436548223350254, '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}}
Uptake of tritiated thymidine by epidermal melanocytes of hairless mice during ultraviolet light radiation.

The backs of male hairless mice were daily exposed to ultraviolet radiation mostly composed of 2536 A wavelength, 6 times per week for a total of 9 exposures. Skin specimens were taken 24 hours after the last exposure. Six hours prior to sacrifice, 40 μCi of tritiated thymidine was injected intradermally at each site irradiated. Frozen vertical sections and split epidermal sheets were incubated for the dopa reaction and then processed with auto-radiographic labeling technique. The uptake of tritiated thymidine by epidermal melanocytes was seen in the autoradiograms using vertical sections but not in those using split epidermal sheets. Cell counts revealed that approximately 1.1 per cent of dopa-positive melanocytes were labeled. It seems unlikely, based on our results, that the populational increase in melanocytes during repeated ultraviolet radiation is due exclusively to the proliferation of melanocytes. Accordingly, it would suggest that the increase in melanocytes is induced through activation of pigment formation in inactive melanocytes or another possible mechanism as yet undemonstrated in addition to the proliferation of melanocytes.