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This is the largest described lung cancer stage-shift in association with a symptom awareness campaign. A causal link between the campaign and stage-shift cannot be proven but appears plausible. Limitations of the analysis include a lack of contemporary control population.

This article was prepared under the auspices of the Analytical Investigations Standing Committee of the Scienti®c Committee of the Association of Clinical Biochemists.

Insulin-like growth factors (IGFs) are crucial for many aspects of development, growth, and metabolism yet control of their activity by IGF-binding proteins (IGFBPs) remains controversial. The effect of IGFBP-1 depends on its phosphorylation status; phosphorylated IGFBP-1 inhibits IGF actions whereas the nonphosphorylated isoform is stimulatory. In order to understand this phenomenon, we purified phosphorylated IGFBP-1 from normal human plasma by immunoaffinity chromatography. Unexpectedly, the resulting preparation enhanced IGFstimulated 3T3-L1 fibroblast proliferation, due to the presence of a co-purified protein of Ϸ700 kDa. Matrixassisted laser desorption ionization-mass spectrometry and Western immunoblotting analysis identified this copurified protein as The insulin-like growth factors (IGFs) 1 have a key role in the metabolism, development, growth, and maintenance of many tissues and organs (1). IGF bioavailability is controlled by a number of binding proteins (IGFBPs) and one of these, IG-FBP-1, is capable of either inhibiting (2-4) or potentiating (5-9) IGF activity at the cellular level.IGFBP-1 inhibits IGF actions by competing with the type 1 IGF receptor for IGF binding, however, the mechanism by which IGFBP-1 enhances IGF activity is less certain. Early work to address this phenomenon resulted in the isolation of two IGFBP-1 isoforms from amniotic fluid, which had similar physicochemical properties but markedly different effects on IGF activity (5). IGFBP-1 association with the cell surface was suggested as an explanation of these findings since only the stimulatory isoform was found to bind to cell membranes. It is now known that IGFBP-1 binds to ␣ 5 ␤ 1 integrin via its RGD site and disruption of this interaction leads to inhibition of the subsequent cellular response (6). Polymerization of IGFBP-1 was also postulated as a mechanism for enhancing IGF action (7) and this has been confirmed recently (8).Many studies have also focused on the influence of phosphorylation in relation to IGFBP-1 effects on IGF activity. The inhibitory isoform purified by Busby et al. (5) was subsequently shown to be phosphorylated (9) whereas the stimulatory preparation contained nonphosphorylated IGFBP-1. Highly phosphorylated IGFBP-1, which is the only form found in plasma (10) has a high affinity for IGF-I (9, 11) and can therefore inhibit IGF-I actions by sequestering it from cell surface receptors. Nonphosphorylated IGFBP-1, which has a relatively low affinity for IGF (9, 11) is thought to allow more IGF/IGF receptor interactions and this hypothesis has been supported by numerous in vitro studies (9,(12)(13)(14). However, it is unclear whether in vivo alteration of IGFBP-1 phosphorylation status represents an important mechanism for regulating IGF bioavailability in the non-pregnant adult, since non-and lesser phosphorylated isoforms of IGFBP-1 are only present at high concentrations during pregnancy (10,15).In the light of the above findings, we were surprised to observe that phosphorylated IGFBP-1 purified from ...

BackgroundCrystallin fragments are known to aggregate and cross-link that lead to cataract development. This study has been focused on determination of post-translational modifications (PTMs) of human lens crystallin fragments, and their aggregation properties.MethodsFour crystallin fragments-containing fractions (Fraction I [∼3.5 kDa species], Fraction II [∼3.5–7 kDa species], Fraction III [∼7–10 kDa species] and Fraction IV [>10–18 kDa species]), and water soluble high molecular weight (WS-HMW) protein fraction were isolated from water soluble (WS) protein fraction of human lenses of 50–70 year old-donors. The crystallin fragments of the Fractions I–IV were separated by two-dimensional (2D)-gel electrophoresis followed by analysis of their gel-spots by mass spectrometry. The Fractions I–IV were examined for their molecular mass, particle-diameters, amyloid fibril formation, and for their aggregation by themselves and with WS-HMW proteins.ResultsCrystallin fragments in Fractions I–IV were derived from α-, β- and γ-crystallins, and their 2D-gel separated spots contained multiple crystallins with PTMs such as oxidation, deamidation, methylation and acetylation. Crystallin fragments from all the four fractions exhibited self-aggregated complexes ranging in Mr from 5.5×105 to 1.0×108 Da, with diameters of 10–28 nm, and amyloid fibril-like formation, and aggregation with WS-HMW proteins.ConclusionThe crystallin fragments exhibited several PTMs, and were capable of forming aggregated species by themselves and with WS-HMW proteins, suggesting their potential role in aggregation process during cataract development.General significanceCrystallin fragments play a major role in human cataract development.

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