Evaluation of QSAR models for predicting mutagenicity: outcome of the Second Ames/QSAR international challenge project

Quantitative structure-activity relationship (QSAR) models are powerful in silico tools for predicting the mutagenicity of unstable compounds, impurities and metabolites that are difficult to examine using the Ames test. Ideally, Ames/QSAR models for regulatory use should demonstrate high sensitivity, low false-negative rate and wide coverage of chemical space. To promote superior model development, the Division of Genetics and Mutagenesis, National Institute of Health Sciences, Japan (DGM/NIHS), conducted the Second Ames/QSAR International Challenge Project (2020-2022) as a successor to the First Project (2014-2017), with 21 teams from 11 countries participating. The DGM/NIHS provided a curated training dataset of approximately 12,000 chemicals and a trial dataset of approximately 1,600 chemicals, and each participating team predicted the Ames mutagenicity of each trial chemical using various Ames/QSAR models. The DGM/NIHS then provided the Ames test results for trial chemicals to assist in model improvement. Although overall model performance on the Second Project was not superior to that on the First, models from the eight teams participating in both projects achieved higher sensitivity than models from teams participating in only the Second Project. Thus, these evaluations have facilitated the development of QSAR models.

Enhancing interprofessional practice through the co-design of a holistic culturally and developmentally informed First Nations child health assessment

BACKGROUND

This qualitative study explored staff experiences of co-designing and implementing a novel interprofessional (IP) First Nations child health assessment (the helpful check), developed in partnership with a remote North-Queensland Aboriginal CommunityControlled Health Organisation.

METHOD

Eleven staff across two teams (family health and allied health) were involved in co-designing and implementing the child health assessment and associated IP practices. Interviews were undertaken using a semi-structured interview template and were audio recorded and transcribed verbatim. Data were analysed using thematic analysis.

RESULTS

Three overarching themes were developed: (1) connect teams by building strong relationships; (2) leave space for helpful check processes to evolve; and (3) integrate helpful check processes into routine practice to sustain change.

CONCLUSIONS

Results demonstrate how the incorporation of IP practices into a remote primary healthcare setting led to perceived benefits for both the health service staff and clients.

The impact of auditory white noise on semantic priming

It has been proposed that white noise can improve cognitive performance for some individuals, particularly those with lower attention, and that this effect may be mediated by dopaminergic circuitry. Given existing evidence that semantic priming is modulated by dopamine, this study investigated whether white noise can facilitate semantic priming. Seventy-eight adults completed an auditory semantic priming task with and without white noise, at either a short or long inter-stimulus interval (ISI). Measures of both direct and indirect semantic priming were examined. Analysis of the results revealed significant direct and indirect priming effects at each ISI in noise and silence, however noise significantly reduced the magnitude of indirect priming. Analyses of subgroups with higher versus lower attention revealed a reduction to indirect priming in noise relative to silence for participants with lower executive and orienting attention. These findings suggest that white noise focuses automatic spreading activation, which may be driven by modulation of dopaminergic circuitry.

A plaque index for occlusal surfaces and fissures. Measurement of repeatability and plaque removal

Plaque indices have largely been developed for buccal and lingual tooth surfaces. There has been minimal interest in plaque accumulation on occlusal surfaces despite the predilection for caries at these sites. A numerical plaque index (0-5) is described based on the presence and distribution of plaque in the fissures and over the occlusal surfaces of permanent molar and premolar teeth. The repeatability of a single examiner in scoring the index was performed using 4 groups of 10 subjects. Each group of volunteers suspended tooth cleaning for 48 h and the index scored after disclosing plaque deposits. The index was rescored 60-90 min later. Plaque area was also determined by drawing the outline of plaque onto grids. Except for one condition of repeatability for one group, the 4 conditions of repeatability in scoring the index were met for all 4 groups of subjects. The sensitivity of the index and area recordings to detect plaque removed by brushing was then evaluated. A group of 10 subjects had plaque scored by index and area after suspending toothcleaning for 48 h. Subjects were then randomly allocated to brush or not brush their teeth and plaque rescored. The experiment was then repeated and brushing or not brushing crossed over. Highly significant differences between brushing and no brushing plaque indices and areas were determined. In conclusion, the occlusal fissure plaque index was easy to apply, repeatable and sufficiently sensitive to detect plaque removed by brushing. The index could find use as an additional measure of oral hygiene, in clinical trials on plaque control and possibly epidemiological studies relating to caries.

The cardiopulmonary cost of backward walking at selected speeds

Backward walking has been advocated as a method of maintaining cardiovascular conditioning in patients undergoing knee rehabilitation because it may decrease patellofemoral joint compressive forces. The primary purpose of this study was to determine the relationship between the rate of oxygen consumption (VO2) and backward walking speed. Twenty-five healthy males, aged 18-35 years, participated in this study. The rate of oxygen consumption and heart rate were measured at the backward walking speeds of 0.89, 1.12, 1.34, 1.56, and 1.79 m/sec (2.0, 2.5, 3.0, 3.5, and 4.0 miles/hour, respectively). Analysis revealed a direct, curvilinear relationship between VO2 and backward walking speed. This research provides information that can be used to prescribe a backward walking rehabilitation program which may be appropriate to maintain aerobic fitness levels during rehabilitation of patients with patellofemoral pain syndrome.

SPROUT: recent developments in the de novo design of molecules

SPROUT is a computer program for constrained structure generation. It is designed to generate molecules for a range of applications in molecular recognition. The program uses a number of approximations that enable a wide variety of diverse structures to be generated. Practical use of the program is demonstrated in two examples. The first demonstrates the ability of the program to generate candidate inhibitors for a receptor site of known 3D structure, specifically the GDP binding site of p21. In the second example, structures are generated to fit a pharmacophore hypothesis that models morphine agonists.

Serum lipoproteins and atherosclerosis in animals

The lipoproteins have been examined in more than 300 serum or plasma samples taken during life or at post mortem from a fairly wide range of mammals, birds and reptiles. The material, which was collected over a period of several years, was subjected to a limited range of lipid analyses, but all specimens were submitted to electrophoresis with paper or cellulose acetate membrane as supporting medium. The lipoprotein pattern in mammals appears to be basically similar to that in man, but there are wide variations in lipid concentrations; the highest levels being found in bears, seals and primates. High concentrations were also observed in many birds and a few reptiles, but the lipoprotein patterns in these vertebrates differ from those in mammals and are further greatly modified by oviparity. Semi-quantitative data on the degree of atherosclerosis were available on the animals that died. There was only a crude positive correlation between the intensity of the arterial disease and high serum beta-lipoprotein levels, and it was concluded that the latter are probably of only secondary importance in the development of spontaneous atherosclerosis in animals.