{'fraction_non_alphanumeric': 0.030890369473046637, 'fraction_numerical': 0.005451241671714113, 'mean_word_length': 5.073529411764706, '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}}
Alveolar macrophages release an insulin-like growth factor I-type molecule.

Human alveolar macrophages, when activated, release a progression-type growth factor for fibroblasts that signals "competent" fibroblasts to replicate. The present study demonstrates that this growth activity is an insulin-like growth factor I (IGF-I)-type molecule. Partial purification of medium conditioned by activated alveolar macrophages using ion exchange and gel filtration chromatography revealed an IGF-I molecule as detected by an anti-IGF-I polyclonal antibody and that the specific activity of the progression-type growth activity tracked with the amount of IGF-I present. In a serum-free complementation test, the increase in fibroblast proliferation by alveolar macrophage IGF-I was reduced in a dose-response manner with an anti-IGF-I monoclonal antibody. The alveolar macrophage IGF-I displaced 125I-IGF-I from its receptor in a binding assay utilizing human lung fibroblasts and it stimulated type I IGF receptors purified from human lung fibroblasts to phosphorylate a tyrosine-containing artificial substrate. In contrast to the 7.6-kD serum IGF-I, gel chromatography revealed that the alveolar macrophage IGF-I had an apparent molecular mass of 26 kD, similar to other tissue IGF-Is. Alveolar macrophages expressed IGF-I mRNA transcripts as detected by solution hybridization using a 32P-labeled riboprobe complementary to exons I-II-III of the IGF-I gene. In the context of the known functions of the family of IGF-I molecules in cell growth, IGF-I released by activated alveolar macrophages may play a role in acute and chronic inflammatory disorders.