Out of Control? Managing Baseline Variability in Experimental Studies with Control Groups

Moser, Paul

doi:10.1007/164_2019_280

Cited by 19 publications

(12 citation statements)

References 57 publications

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“…On the other hand, the positive control group is the one that is not subjected to the experimental treatment but is instead exposed to another treatment that is known to have a similar effect to the experimental treatment. When the control groups are used correctly, they not only validate the experiment but also offer the foundation for the analysis of the effect of the applied treatments [63]. Hence, they must be treated as any other experimental group in terms of preparation, randomization, blinding and other factors.…”

Section: Discussionmentioning

confidence: 99%

Remineralizing Effects of Resin-Based Dental Sealants: A Systematic Review of In Vitro Studies

et al. 2022

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The incorporation of remineralizing additives into sealants has been considered as a feasible way to prevent caries by potential remineralization through ions release. Thus, this systematic review aimed to identify the remineralizing additives in resin-based sealants (RBS) and assess their performance. Search strategies were built to search four databases (PubMed, MEDLINE, Web of Science and Scopus). The last search was conducted in June 2020. The screening, data extraction and quality assessment were completed by two independent reviewers. From the 8052 screened studies, 275 full-text articles were assessed for eligibility. A total of 39 laboratory studies matched the inclusion criteria. The methodologies used to assess the remineralizing effect included microhardness tests, micro-computed tomography, polarized-light microscopy, ions analysis and pH measurements. Calcium phosphate (CaP), fluoride (F), boron nitride nanotubes (BNN), calcium silicate (CS) and hydroxyapatite (HAP) were incorporated into resin-based sealants in order to improve their remineralizing abilities. Out of the 39 studies, 32 studies focused on F as a remineralizing agent. Most of the studies confirmed the effectiveness of F and CaP on enamel remineralization. On the other hand, BNN and CS showed a small or insignificant effect on remineralization. However, most of the included studies focused on the short-term effects of these additives, as the peak of the ions release and concentration of these additives was seen during the first 24 h. Due to the lack of a standardized in vitro study protocol, a meta-analysis was not conducted. In conclusion, studies have confirmed the effectiveness of the incorporation of remineralizing agents into RBSs. However, the careful interpretation of these results is recommended due to the variations in the studies’ settings and assessments.

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Section: Discussionmentioning

confidence: 99%

Remineralizing Effects of Resin-Based Dental Sealants: A Systematic Review of In Vitro Studies

et al. 2022

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“…nutrient effect, fortuitous assembly of an unrelated biological motif etc.). This is the provision of a negative control (Moser, 2020). How best to scramble aa sequences?…”

Section: Discussionmentioning

confidence: 99%

Hexapeptides from a mammalian inhibitory hormone activate and inactivate nematode reproduction

Hart¹,

Mohan

Davies

et al. 2021

Preprint

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Increased reproduction (x3) of the entomopathogenic nematode Steinernema siamkayai occurred when exposed to one synthetic peptide (IEPVFT), while the fecundity of worms exposed to hexamer (KLKMNG) was reduced (x0.5). These hexamers were opposite ends of a 14 amino acid (aa) synthetic peptide KLKMNGKNIEPVFT (EPL030). The bioactivity of the hexamers is surprising it is a scrambled-sequence control of another peptide, MKPLTGKVKEFNNI (EPL001) which are bioinformatically obscure. EPL001 emerged from a physicochemical fractionation aimed at finding a postulated hormone that is reproductively related and tissue-mass reducing and has antiproliferative effects on human prostate cancer cells and rat bone marrow cells in vitro. Intracerebroventricular infusion of EPL001 in sheep was associated with elevated growth hormone in peripheral blood and reduced prolactin. The highly dissimilar EPL001 and EPL030 nonetheless have the foregoing biological effects in common in mammalian systems, while being divergently pro- and anti-fecundity respectively in the nematode Caenorhabditis elegans. Immunoprecipitation of EPL001 using an anti-EPL001 antibody suggests it encodes the sheep neuroendocrine prohormone secretogranin II (sSgII). Using bespoke bioinformatics with six sSgII residues deduced bioactivity to key aa: MKPLTGKVKEFNNI. Peptides more potent as cell inhibitors than EPL001 suggest a stereospecific bimodular tri-residue signature (i.e. simultaneous accessibility for binding of two specific trios of aa side chains, MKP & VFN). An evolutionarily conserved receptor is conceptualised as having dimeric binding sites, each with ligand-matching bimodular stereocentres. Sequence analysis and computational modelling suggest the activity of the control peptide EPL030 and its N- and C-terminal hexapeptide progeny is due the novel hormonal motif MKPVFN.

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“…Although different methods may produce control groups of different quality [15] (depending on the nature of the population used for selection), studies published in the literature most often only use the greedy PSM matching. Despite the popularity of the widely applied greedy k-nn-based PSM method, it has also got many criticisms [16][17][18][19][20][21][22]. All these articles pointed out that the PSM method in some cases and studies may result in a not well-balanced control group.…”

Section: Related Workmentioning

confidence: 99%

Optimized Weighted Nearest Neighbours Matching Algorithm for Control Group Selection

Szekér

Vathy-Fogarassy

2021

Algorithms

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An essential criterion for the proper implementation of case-control studies is selecting appropriate case and control groups. In this article, a new simulated annealing-based control group selection method is proposed, which solves the problem of selecting individuals in the control group as a distance optimization task. The proposed algorithm pairs the individuals in the n-dimensional feature space by minimizing the weighted distances between them. The weights of the dimensions are based on the odds ratios calculated from the logistic regression model fitted on the variables describing the probability of membership of the treated group. For finding the optimal pairing of the individuals, simulated annealing is utilized. The effectiveness of the newly proposed Weighted Nearest Neighbours Control Group Selection with Simulated Annealing (WNNSA) algorithm is presented by two Monte Carlo studies. Results show that the WNNSA method can outperform the widely applied greedy propensity score matching method in feature spaces where only a few covariates characterize individuals and the covariates can only take a few values.

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Out of Control? Managing Baseline Variability in Experimental Studies with Control Groups

Cited by 19 publications

References 57 publications

Remineralizing Effects of Resin-Based Dental Sealants: A Systematic Review of In Vitro Studies

Remineralizing Effects of Resin-Based Dental Sealants: A Systematic Review of In Vitro Studies

Hexapeptides from a mammalian inhibitory hormone activate and inactivate nematode reproduction

Optimized Weighted Nearest Neighbours Matching Algorithm for Control Group Selection

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