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Objectives: The World Health Organization (WHO) highlights parous women as a key population for monitoring trends of physical activity (PA). We aimed to estimate the proportion of Danish women non-adhering to WHO PA guidelines in parous women compared with nulliparous women and to describe leisure-time PA intensity in each of these groups., Study Design: Cross-sectional study., Methods: This population-based study builds on a sample of 27,668 women aged 16-40 years from the Danish National Health Survey 2021. These data were linked with childbirth data from the Danish National Birth Registry. The primary outcome was self-reported weekly hours of moderate to vigorous leisure-time PA (MVPA) dichotomized into: (i) adhering to WHO guidelines for MVPA or (ii) not adhering to WHO guidelines for MVPA. Binomial regression analysis was used to calculate prevalence proportions (PP) and prevalence proportion ratios (PPR)., Results: Of the 27,668 women, a total of 20,022 were included; 9338 (46.6%) parous women and 10,684 (53.4%) nulliparous women. The PP of women non-adhering to WHO PA guidelines was 63.8% (95% CI 62.9-64.8) for parous and 51.3% (95% CI 50.4-52.3) for nulliparous women, corresponding to a PPR of 1.24 (95% CI 1.21; 1.27)., Conclusions: The proportion of parous women who did not adhere to WHO PA guidelines for MVPA was 24% higher than that of nulliparous women. This highlights parous women as a subgroup of the adult population at increased risk of non-adherence to WHO PA guidelines. These findings call for future research to inform new strategies aiming to promote PA in parous women., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

An assay for studying the proteolytic activity of endopeptidases using a biotinylated and cysteine-modified peptide has been developed. This assay is rapid, sensitive, and reproducible. Although used here specifically for the enzyme which cleaves at the amino terminus (N-terminus) of beta-amyloid peptide (BAP); this type of radiolabeled substrate is readily applied to the analysis and detection of other endoprotease activities. This method relies on a peptide substrate which contains: (a) the amino acids flanking the enzymatic cleavage site, (b) an added cysteine at the carboxy-terminus to allow for incorporation of radiolabel via an addition reaction with tritiated N-[ethyl-1,2-3H]maleimide (3H-NEM), and (c) a biotin at the N-terminus to allow for binding to avidin-coated scintillation proximity assay (SPA) beads. It has been suggested that the enzyme involved in the N-terminal cleavage of amyloid precursor peptide to generate BAP is a chymotrypsin-like serine protease such as cathepsin G. To study this enzymatic activity and to screen for its inhibitors, we have synthesized the peptide biotin-SEVKMDAEFdC which contains the amino acids flanking the N-terminal cleavage site of BAP. Tritiated NEM is covalently bound to the cysteine at the carboxy-terminal end and the labeled peptide is purified by reverse-phase high-performance liquid chromatography. Following digestion of 3H-NEM-labeled peptide by cathepsin G, the biotinylated side of the cleaved peptide is bound to the SPA bead, while the tritiated end of the cleaved peptide remains in solution. Enzymatic hydrolysis is measured as the loss of 3H-induced scintillation signal. This method has allowed us to rapidly determine kinetic constants and develop a high throughput screen to study inhibition of cathepsin G cleavage in a native peptide context.

We have used an S1 nuclease protection strategy to measure alternatively spliced amyloid precursor protein (APP) mRNAs associated with Alzheimer's disease (AD) to determine whether the expression of either one or more of the transcripts correlate with observed amyloid plaque pathology. Comparison of AD with normal cortex reveals that increasing plaque density parallels an increase in the fraction of APP-695 and a corresponding decrease in APP-770 and 751 mRNA fractions. A specific increase of APP-695, the protease inhibitor-lacking APP RNA form, in those brain regions most involved with amyloid plaque formation, suggests that an imbalance in the protease inhibitor is potentially significant in the disease. These data are consistent with cellular/tissue region-specific regulation of alternative splicing accounting for AD-related changes in the expression of APP mRNA forms.

Using an S1 nuclease protection assay, we have identified a novel "variant" Amyloid Precursor Protein (APP) RNA in human brain which is 3-6-fold more abundant than APP-770, but less abundant than APP-751 or APP-695. This variant, referred to as amyloid precursor-related protein 365 (APRP-365), is not detected in mouse and rat brain RNAs. A 1.6 kilo-basepair cDNA clone corresponding to this variant APP RNA predicts the existence of a 365 amino acid protein that is similar to the amino-terminal end of APP-770 but lacks the beta-amyloid peptide and any hydrophobic transmembrane spanning domains. In a modified polymerase chain reaction (PCR), we used amplification of reverse transcribed mRNA to confirm and extend our S1 observations. Together, the features of APRP-365 suggest that the human variant is a soluble protein containing a Kunitz protease inhibitor domain.

The carcinogen aflatoxin B1 (AFB1), upon activation to a hypothesized AFB1-2,3-oxide (AFB1-oxide), reacts with DNA guanines. Aflatoxin B1-2,3-dichloride (AFB1-Cl2) was originally synthesized as an electronic analog for the putative AFB1-oxide, which has never been isolated due to presumed reactivity. We have previously shown that AFB1-oxide reacts with base-paired DNA guanines in a sequence-specific manner, as revealed by an alkali-degradation analysis. On the basis of a replication-block analysis, we have shown that AFB1-Cl2 reacts with single-stranded DNA preferentially at inverted repeat sequences, which were suggested to be capable of forming intrastrand base-paired structures. Here, we present data to show the following. Both AFB1-oxide and AFB1-Cl2 react with guanines in double-stranded DNA to induce similar sequence-specific, alkali-labile sites. Reactivity with partial DNA duplexes as well as the use of single-strand specific chemical probes directly demonstrates that AFB1-Cl2, like AFB1-oxide, prefers base-paired guanines over non-base-paired guanines. DNA replication block patterns induced by AFB1-oxide are essentially similar to those induced by AFB1-Cl2. Unexpectedly, and unlike other tested DNA lesions, Mn2+ does not appear to affect the template blocking properties of the adduct formed by AFB1-Cl2 or AFB1-oxide. The sites for replication stoppage as well as the lack of a Mn2+ effect on adducted templates have implications for the mechanisms of mutagenesis by activated AFB1.