{'fraction_non_alphanumeric': 0.035687732342007436, 'fraction_numerical': 0.026765799256505577, 'mean_word_length': 4.8268398268398265, '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}}
Unbiased estimation of total β‐cell number and mean β‐cell volume in rodent pancreas

We describe a method for unbiased assumption‐free estimation of the total number of β‐cells and the mean β‐cell volume in mouse and rat pancreas based on light microscopy. Such a method, which takes advantage of one of the most recent developments in stereology, the fractionator, has not previously been described. It relies on repeated fractionation of the tissue using systematic uniform random sampling combined with an unbiased counting principle. The method was applied to eight BALB/cBom male mice (56 days) and six Lewis/MOL male rats (47 days). In mice, the total number of β‐cells was 1.06±0.07±106 (mean±SEM) per pancreas with a mean β‐cell volume of 1280±17 μm3, while in rats the total β‐cell number was 2.76±0.42±106 per pancreas with a mean β‐cell volume of 1170±65 μm3. Furthermore, the results showed that in both species the biological variability in the total β‐cell volume is due to differences in the number of β‐cells rather than variability of the mean β‐cell volume. The method can be used to give a precise description of number and volume of β‐cells at different ages, and will make it possible to estimate the contributions of hyper/hypotrophia and hyperlhypoplasia to a given induced or spontaneous change in the total β‐cell mass.