Characteristics of successful government-led interventions to support healthier populations: a starting portfolio of positive outlier examples.

Despite progress on the Millennium and Sustainable Development Goals, significant public health challenges remain to address communicable and non-communicable diseases and health inequities. The Healthier Societies for Healthy Populations initiative convened by WHO's Alliance for Health Policy and Systems Research; the Government of Sweden; and the Wellcome Trust aims to address these complex challenges. One starting point is to build understanding of the characteristics of successful government-led interventions to support healthier populations. To this end, this project explored five purposefully sampled, successful public health initiatives: front-of-package warnings on food labels containing high sugar, sodium or saturated fat (Chile); healthy food initiatives (trans fats, calorie labelling, cap on beverage size; New York); the alcohol sales and transport ban during COVID-19 (South Africa); the Vision Zero road safety initiative (Sweden) and establishment of the Thai Health Promotion Foundation. For each initiative a qualitative, semistructured one-on-one interview with a key leader was conducted, supplemented by a rapid literature scan with input from an information specialist. Thematic analysis of the five interviews and 169 relevant studies across the five examples identified facilitators of success including political leadership, public education, multifaceted approaches, stable funding and planning for opposition. Barriers included industry opposition, the complex nature of public health challenges and poor interagency and multisector co-ordination. Further examples building on this global portfolio will deepen understanding of success factors or failures over time in this critical area.

Design of experiments: an efficient strategy to identify factors influencing extraction and derivatization of Arabidopsis thaliana samples in metabolomic studies with gas chromatography/mass spectrometry.

The usual aim in metabolomic studies is to quantify the entire metabolome of each of a series of biological samples. To do this for complex biological matrices, e.g., plant tissues, efficient and reproducible extraction protocols must be developed. However, derivatization protocols must also be developed if GC/MS (one of the mostly widely used analytical methods for metabolomics) is involved. The aim of this study was to investigate how different chemical and physical factors (extraction solvent, derivatization reagents, and temperature) affect the extraction and derivatization of the metabolome from leaves of the plant Arabidopsis thaliana. Using design of experiment procedures, variation was systematically introduced, and the effects of this variation were analyzed using regression models. The results show that this approach allows a reliable protocol for metabolomic analysis of Arabidopsis to be determined with a relatively limited number of experiments. Following two different investigations an extraction and derivatization protocol was chosen. Further, the reproducibility of the analysis of 66 endogenous compounds was investigated, and it was shown that both hydrophilic and lipophilic compounds were detected with high reproducibility.

Derivatization for LC-electrospray ionization-MS: a tool for improving reversed-phase separation and ESI responses of bases, ribosides, and intact nucleotides.

We have developed a method for analyzing polar compounds by reversed-phase LC-ESI-MS following esterification of the analytes' free hydroxyl groups with propionyl or benzoyl acid anhydride. The method was applied to members of the plant hormone group cytokinins, which includes adenine bases, ribosides/glycosides, and nucleotides substituted at N-6 with an isoprenoid side chain, spanning a wide range of polarity. It was also used to analyze other compounds of biological importance, e.g., the nucleotides AMP, ADP, and ATP. The formation of more hydrophobic derivatives had a significant impact on two aspects of the analysis. The retention on a reversed-phase material was greatly increased without the use of any acetate/formate buffer or ion pairing reagent, and the ESI response was enhanced, due to the higher surface activities of the derivatives. Detection limits of propionylated cytokinins were in the high-attomole to low-femtomole range, an improvement by factors of 10-100 compared to previously reported figures. Using an automated SPE-based purification method, 12 endogenous cytokinins were quantified in extracts from 20- to 100-mg samples of leaves (from the plant Arabidopsis thaliana) with high accuracy and precision. Furthermore, the chromatographic properties of the benzoylated AMP, ADP, and ATP in the reversed-phase LC-MS system were much better in terms of retention, separation, and sensitivity than those of their underivatized counterparts, even without the use of any ion pairing reagent. Our data show that derivatization followed by LC-ESI-MS is an effective strategy for analyzing low molecular weight compounds, enabling compounds with a wide range of polarity to be determined in a single-injection LC-MS analysis.

A strategy for identifying differences in large series of metabolomic samples analyzed by GC/MS.

In metabolomics, the purpose is to identify and quantify all the metabolites in a biological system. Combined gas chromatography and mass spectrometry (GC/MS) is one of the most commonly used techniques in metabolomics together with 1H NMR, and it has been shown that more than 300 compounds can be distinguished with GC/MS after deconvolution of overlapping peaks. To avoid having to deconvolute all analyzed samples prior to multivariate analysis of the data, we have developed a strategy for rapid comparison of nonprocessed MS data files. The method includes baseline correction, alignment, time window determinations, alternating regression, PLS-DA, and identification of retention time windows in the chromatograms that explain the differences between the samples. Use of alternating regression also gives interpretable loadings, which retain the information provided by m/z values that vary between the samples in each retention time window. The method has been applied to plant extracts derived from leaves of different developmental stages and plants subjected to small changes in day length. The data show that the new method can detect differences between the samples and that it gives results comparable to those obtained when deconvolution is applied prior to the multivariate analysis. We suggest that this method can be used for rapid comparison of large sets of GC/MS data, thereby applying time-consuming deconvolution only to parts of the chromatograms that contribute to explain the differences between the samples.