Core requirements of frailty screening in the emergency department: an international Delphi consensus study.

INTRODUCTION: Frailty is associated with adverse outcomes among patients attending emergency departments (EDs). While multiple frailty screens are available, little is known about which variables are important to incorporate and how best to facilitate accurate, yet prompt ED screening. To understand the core requirements of frailty screening in ED, we conducted an international, modified, electronic two-round Delphi consensus study. METHODS: A two-round electronic Delphi involving 37 participants from 10 countries was undertaken. Statements were generated from a prior systematic review examining frailty screening instruments in ED (logistic, psychometric and clinimetric properties). Reflexive thematic analysis generated a list of 56 statements for Round 1 (August-September 2021). Four main themes identified were: (i) principles of frailty screening, (ii) practicalities and logistics, (iii) frailty domains and (iv) frailty risk factors. RESULTS: In Round 1, 13/56 statements (23%) were accepted. Following feedback, 22 new statements were created and 35 were re-circulated in Round 2 (October 2021). Of these, 19 (54%) were finally accepted. It was agreed that ideal frailty screens should be short (<5 min), multidimensional and well-calibrated across the spectrum of frailty, reflecting baseline status 2-4 weeks before presentation. Screening should ideally be routine, prompt (<4 h after arrival) and completed at first contact in ED. Functional ability, mobility, cognition, medication use and social factors were identified as the most important variables to include. CONCLUSIONS: Although a clear consensus was reached on important requirements of frailty screening in ED, and variables to include in an ideal screen, more research is required to operationalise screening in clinical practice.

Macrowear effects of external quartz abrasives of different size and concentration in rabbits (Oryctolagus cuniculus).

External quartz abrasives are one of the driving forces of macrowear in herbivorous animals. We tested to what extent different sizes and concentrations influence their effect on tooth wear. We fed seven pelleted diets varying only in quartz concentration (0%, 4%, and 8%) and size (fine silt: ∼4 µm, coarse silt: ∼50 µm, fine sand: ∼130 µm) to rabbits (Oryctolagus cuniculus, n = 16) for 2 weeks each in a randomized serial experiment. Measurements to quantify wear and growth of incisors and the mandibular first cheek tooth, as well as heights of all other cheek teeth, were performed using calipers, endoscopic examination, and computed tomography scans before and after each feeding period. Tooth growth showed a compensatory correlation with wear. Absolute tooth height (ATH) and relative tooth height (RTH); relative to the 0% quartz "control" diet) was generally lower on the higher concentration and the larger size of abrasives. The effect was more pronounced on the maxillary teeth, on specific tooth positions and the right jaw side. When offered the choice between different sizes of abrasives, the rabbits favored the silt diets over the control and the fine sand diet; in a second choice experiment with different diets, they selected a pelleted diet with coarse-grained sand, however. This study confirms the dose- and size-dependent wear effects of external abrasives, and that hypselodont teeth show compensatory growth. The avoidance of wear did not seem a priority for animals with hypselodont teeth, since the rabbits did not avoid diets inducing a certain degree of wear.

Tooth wear, growth and height in rabbits (Oryctolagus cuniculus) fed pelleted or extruded diets with or without added abrasives.

Among the different factors thought to affect dental wear, dietary consistency is possibly the least investigated. To understand tooth wear of herbivorous animals consuming different dietary consistencies with different abrasive potential, we fed 14 rabbits (Oryctolagus cuniculus) exclusively with a timothy grassmeal-based diet in either pelleted or extruded form, or the same diets with an addition of 5% fine sand abrasives (mean size 130 µm). First, we offered the rabbits the pelleted and extruded diets as well as the pelleted control and pelleted abrasive diet in a two-stage preference experiment. Then, the rabbits received each diet for 2 weeks in a randomised serial feeding experiment, where each animal served as its own control. Tooth measurements for wear, growth and height were achieved using a manual calliper, endoscopic examination and CT scans. The analysis of the diets as fed showed almost identical mean particle size, but the extruded diet had a lower density (volume/mass) and softer consistency compared to the pelleted one and was favoured by most rabbits. The rabbits selected against the diet with sand during the preference experiment, possibly because it caused more tooth wear, especially on the teeth most exposed to wear along the upper tooth row (upper P4 and M1). The maxillary teeth also showed evidence of an increased chewing laterality by the end of the experiment. The extruded diet led to a significantly lower cheek teeth height than the pelleted diet, potentially due to the higher chewing effort needed for a similar dry matter intake. The results suggest that dietary hardness alone is a poor predictor of dental wear. The regrowth of the teeth matched wear consistently.

Gadolinium Tissue Distribution in a Large-Animal Model after a Single Dose of Gadolinium-based Contrast Agents.

Background There is an ongoing scientific debate about the degree and clinical importance of gadolinium deposition in the brain and other organs after administration of gadolinium-based contrast agents (GBCAs). While most published data focus on gadolinium deposition in the brain, other organs are rarely investigated. Purpose To compare gadolinium tissue concentrations in various organs 10 weeks after one injection (comparable to a clinically applied dose) of linear and macrocyclic GBCAs in a large-animal model. Materials and Methods In this prospective animal study conducted from March to May 2018, 36 female Swiss-Alpine sheep (age range, 4-10 years) received one injection (0.1 mmol/kg) of macrocyclic GBCAs (gadobutrol, gadoteridol, and gadoterate meglumine), linear GBCAs (gadodiamide and gadobenate dimeglumine), or saline. Ten weeks after injection, sheep were sacrificed and tissues were harvested. Gadolinium concentrations were quantified with inductively coupled plasma mass spectrometry (ICP-MS). Histologic staining was performed. Data were analyzed with nonparametric tests. Results At 10 weeks after injection, linear GBCAs resulted in highest mean gadolinium concentrations in the kidney (502 ng/g [95% CI: 270, 734]) and liver (445 ng/g [95% CI: 202, 687]), while low concentrations were found in the deep cerebellar nuclei (DCN) (30 ng/g [95% CI: 20, 41]). Tissue concentrations of linear GBCAs were three to 21 times higher compared with those of macrocyclic GBCAs. Administered macrocyclic GBCAs resulted in mean gadolinium concentrations of 86 ng/g (95% CI: 31, 141) (P = .08) in the kidney, 21 ng/g (95% CI: 4, 39) (P = .15) in liver tissue, and 10 ng/g (95% CI: 9, 12) (P > .99) in the DCN, which were not significantly elevated when compared with concentrations in control animals. No histopathologic alterations were observed irrespective of tissue concentrations within any examined organ. Conclusion Ten weeks after one injection of a clinically relevant dose of gadolinium-based contrast agents, the liver and kidney appeared to be reservoirs of gadolinium; however, despite gadolinium presence, no tissue injury was detected. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Clément in this issue.

Agricultural origins on the Anatolian plateau.

This paper explores the explanations for, and consequences of, the early appearance of food production outside the Fertile Crescent of Southwest Asia, where it originated in the 10th/9th millennia cal BC. We present evidence that cultivation appeared in Central Anatolia through adoption by indigenous foragers in the mid ninth millennium cal BC, but also demonstrate that uptake was not uniform, and that some communities chose to actively disregard cultivation. Adoption of cultivation was accompanied by experimentation with sheep/goat herding in a system of low-level food production that was integrated into foraging practices rather than used to replace them. Furthermore, rather than being a short-lived transitional state, low-level food production formed part of a subsistence strategy that lasted for several centuries, although its adoption had significant long-term social consequences for the adopting community at Boncuklu. Material continuities suggest that Boncuklu's community was ancestral to that seen at the much larger settlement of Çatalhöyük East from 7100 cal BC, by which time a modest involvement with food production had been transformed into a major commitment to mixed farming, allowing the sustenance of a very large sedentary community. This evidence from Central Anatolia illustrates that polarized positions explaining the early spread of farming, opposing indigenous adoption to farmer colonization, are unsuited to understanding local sequences of subsistence and related social change. We go beyond identifying the mechanisms for the spread of farming by investigating the shorter- and longer-term implications of rejecting or adopting farming practices.

Dust and grit matter: abrasives of different size lead to opposing dental microwear textures in experimentally fed sheep (Ovis aries).

External abrasives ingested along with the herbivore diet are considered main contributors to dental wear, though how the different sizes and concentrations of these abrasives influence wear remains unclear. Dental microwear texture analysis (DMTA) is an established method for dietary reconstruction which describes a tooth's surface topography on a micrometre scale. The method has yielded conflicting results as to the effect of external abrasives. In the present study, a feeding experiment was performed on sheep (Ovis aries) fed seven diets of different abrasiveness. Our aim was to discern the individual effects of size (4, 50 and 130 µm) and concentration (0%, 4% and 8% of dry matter) of abrasives on dental wear, applying DMTA to four tooth positions. Microwear textures differed between individual teeth, but surprisingly, showed no gradient along the molar tooth row, and the strongest differentiation of experimental groups was achieved when combining data of all maxillary molars. Overall, a pattern of increasing height, volume and complexity of the tooth's microscopic surface appeared with increasing size of dietary abrasives, and when compared with the control, the small abrasive diets showed a polishing effect. The results indicate that the size of dietary abrasives is more important for dental microwear texture traces than their concentration, and that different sizes can have opposing effects on the dietary signal. The latter finding possibly explains conflicting evidence from previous experimental DMTA applications. Further exploration is required to understand whether and how microscopic traces created by abrasives translate quantitatively to tissue loss.

The way wear goes: phytolith-based wear on the dentine-enamel system in guinea pigs (Cavia porcellus).

The effect of phytoliths on tooth wear and function has been contested in studies of animal-plant interactions. For herbivores whose occlusal chewing surface consists of enamel ridges and dentine tissue, the phytoliths might particularly erode the softer dentine, exposing the enamel ridges to different occlusal forces and thus contributing to enamel wear. To test this hypothesis, we fed guinea pigs (Cavia porcellus; n = 36 in six groups) for three weeks exclusively on dry or fresh forage of low (lucerne), moderate (fresh timothy grass) or very high (bamboo leaves) silica content representing corresponding levels of phytoliths. We quantified the effect of these treatments with measurements from micro-computed tomography scans. Tooth height indicated extreme wear due to the bamboo diet that apparently brought maxillary incisors and molars close to the minimum required for functionality. There were negative relationships between a cheek tooth's height and the depth of its dentine basin, corroborating the hypothesis that dentine erosion plays an important role in herbivore tooth wear. In spite of lower body mass, bamboo-fed animals paradoxically had longer cheek tooth rows and larger occlusal surfaces. Because ever-growing teeth can only change in shape from the base upwards, this is a strong indication that failure to compensate for wear by dental height-growth additionally triggered general expansive growth of the tooth bases. The results suggest that enamel wear may intensify after enamel has been exposed due to a faster wear of the surrounding dentine tissue (and not the other way around), and illustrate a surprising plasticity in the reactivity of this rodent's system that adjusts tooth growth to wear.

Physical characteristics of gastrointestinal content of llama (Lama glama).

Changes in digesta dry matter (DM) and mean digesta particle size (MPS) along the gastrointestinal tract are well known in ruminants, but not in camelids. We collected digesta from the dorsal (d) and ventral (v) first forestomach compartment (C1), the second forestomach compartment (C2), three proximal segments and the subsequent glandular part of the third compartment (C3A-D), the caecum and the faeces twelve llamas (Lama glama). DM analysis indicates the presence of digesta stratification in the C1, the presence of fluid in the C2 to facilitate the sorting function of this compartment, the fluid-absorbing function of the proximal parts of the C3, the secretion of enzymes and digestive acids in the C3D, and the water-resorbing function of the lower intestinal tract. These findings illustrate the functional resemblance between the gastrointestinal tract of camelids and cattle-like ruminants (C1 equivalent to the rumen with stratified contents, C2 to the reticulum, C3A/B/C to the omasum and C3D to the abomasum). MPS analysis revealed a progressive reduction in MPS from the C1 to the distal C3. This gradual transition is different from the clear-cut threshold in ruminants between the reticulum and the omasum and had so far only been described in dromedaries (Camelus dromedarius). These findings indicate that regardless of the convergent property of rumination and resemblance of general mechanisms involved in contents stratification and particle sorting, differences between ruminants and camelids exist that could be interpreted as a more efficient functionality of the ruminant forestomach.

Contaminated fingers: a potential cause of Chlamydia trachomatis-positive urine specimens.

OBJECTIVES: The detection of an STI agent in a urogenital tract (UGT) specimen from a young child is regarded as being indicative of sexual abuse. However, the probabilities of contamination events that could conceivably lead to STI positive specimens in the absence of sexual contact are unclear. The objective was to estimate the potential for fingers that have come in contact with Chlamydia trachomatis-positive urine to detectably contaminate C. trachomatis-negative urine. METHODS: The study design was based on self-experimentation. Dilutions of C. trachomatis elementary bodies (EBs) were prepared. A participant contacted an EB dilution then a urine surrogate specimen. The experiment was performed by three participants using three C. trachomatis isolates, of genotype E, F and B. Two surrogate urine contact methods were used to mimic contamination of a carer assisting with a child's urine collection. All EB dilutions and urine surrogate specimens were subjected to C. trachomatis assay and quantification in a real-time PCR-based diagnostic system. RESULTS: The amplimer crossing point (Cq) for EB dilutions was 10.0±1.6 less than for corresponding finger contacted urine specimens, which corresponds to ~10 µL of EB suspension transferred. This was largely independent of participant identity, C. trachomatis strain or EB dilution. Hand decontamination led to large reductions in EBs transferred, but transfer remained consistently detectable. Recent Cq data from C. trachomatis-positive clinical urine specimens were collated, and 20% clearly contained sufficient C. trachomatis to detectably contaminate another specimen by finger-mediated transfer, as in this experiment. CONCLUSIONS: This study directly demonstrated the potential for urine contaminated fingers to convert a C. trachomatis-negative urine specimen to C. trachomatis positive as a result of contact. Accordingly, procedures for urine specimen collection, particularly from children, need to be designed to prevent contamination.

Spoken language and everyday functioning in 5-year-old children using hearing aids or cochlear implants.

OBJECTIVE: This study investigated the factors influencing 5-year language, speech and everyday functioning of children with congenital hearing loss. DESIGN: Standardised tests including PLS-4, PPVT-4 and DEAP were directly administered to children. Parent reports on language (CDI) and everyday functioning (PEACH) were collected. Regression analyses were conducted to examine the influence of a range of demographic variables on outcomes. STUDY SAMPLE: Participants were 339 children enrolled in the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study. RESULTS: Children's average receptive and expressive language scores were approximately 1 SD below the mean of typically developing children, and scores on speech production and everyday functioning were more than 1 SD below. Regression models accounted for 70-23% of variance in scores across different tests. Earlier CI switch-on and higher non-verbal ability were associated with better outcomes in most domains. Earlier HA fitting and use of oral communication were associated with better outcomes on directly administered language assessments. Severity of hearing loss and maternal education influenced outcomes of children with HAs. The presence of additional disabilities affected outcomes of children with CIs. CONCLUSIONS: The findings provide strong evidence for the benefits of early HA fitting and early CI for improving children's outcomes.

Psychosocial development of 5-year-old children with hearing loss: Risks and protective factors.

OBJECTIVE: The aims of this paper were to report on the global psychosocial functioning of 5-year-old DHH children and examine the risk and protective factors that predict outcomes. DESIGN: A cross-sectional analysis of data collected from a prospective, population-based longitudinal study. STUDY SAMPLE: Parents/caregivers of 356 children completed questionnaires on psychosocial development (CDI, SDQ), functional communication (PEACH) and demographic information. Children completed standardized assessments of non-verbal cognitive ability (WNV) and language (PLS-4). RESULTS: On average, global psychosocial functioning was within the range of typically developing children; however, variability was high and 12% of children had scores that were more than 2 SDs below the norm. Non-verbal cognitive ability, presence of additional disabilities, language and functional communication significantly predicted outcomes. In contrast, type of hearing device, severity of hearing loss and age at intervention did not. CONCLUSION: The global psychosocial functioning of this cohort of 5-year-old DHH children fell within the range of typically developing children. The findings suggest that spoken language ability and functional communication skills are vital for healthy psychosocial development.

Language and speech outcomes of children with hearing loss and additional disabilities: identifying the variables that influence performance at five years of age.

OBJECTIVE: This study examined language and speech outcomes in young children with hearing loss and additional disabilities. DESIGN: Receptive and expressive language skills and speech output accuracy were evaluated using direct assessment and caregiver report. Results were analysed first for the entire participant cohort, and then to compare results for children with hearing aids (HAs) versus cochlear implants (CIs). STUDY SAMPLE: A population-based cohort of 146 five-year-old children with hearing loss and additional disabilities took part. RESULTS: Across all participants, multiple regressions showed that better language outcomes were associated with milder hearing loss, use of oral communication, higher levels of cognitive ability and maternal education, and earlier device fitting. Speech output accuracy was associated with use of oral communication only. Average outcomes were similar for children with HAs versus CIs, but their associations with demographic variables differed. For HA users, results resembled those for the whole cohort. For CI users, only use of oral communication and higher cognitive ability levels were significantly associated with better language outcomes. CONCLUSIONS: The results underscore the importance of early device fitting for children with additional disabilities. Strong conclusions cannot be drawn for CI users given the small number of participants with complete data.

Transference-Focused Psychotherapy in Australian psychiatric training and practice.

OBJECTIVE: This article discusses Transference-Focused Psychotherapy, a contemporary evidence-based and manualised form of psychoanalytic psychotherapy for borderline personality disorder. Transference focused psychotherapy has evolved from decades of research in the object-relations approach developed by Professor Otto Kernberg and his collaborators. It is being adopted increasingly throughout North and South America and Europe, and this article explores the role its adoption might play in psychiatric training as well as public and private service provision contexts in Australia. CONCLUSIONS: Transference focused psychotherapy is readily applicable in a range of training, research and public and private service provision contexts in Australia. A numbers of aspects of current Australian psychiatric training and practice, such as the Royal Australian and New Zealand College of Psychiatrists advanced training certificate, and the Australian medicare schedule, make it especially relevant for this purpose.

The Web-based CanMEDS Resident Learning Portfolio Project (WEBCAM): how we got started.

SUMMARY: The CanMEDS framework is ubiquitous in Canadian postgraduate medical education; however, training programs do not have a universal method of assessing competence. We set out to develop a novel portfolio that allowed trainees to generate a longitudinal record of their training and development within the framework. The portfolio provided an objective means for the residency program director to document and evaluate resident progress within the CanMEDS roles.

The self-perceived knowledge, skills and attitudes of Australian practice nurses in providing nutrition care to patients with chronic disease.

BACKGROUND: Nutrition is important for the management of chronic diseases. While practice nurses have numerous roles in primary care, the expectations on practice nurses to provide nutrition care for chronic disease management are increasing. The self-perceived knowledge, skills and attitudes of practice nurses in providing nutrition care has not been widely investigated. OBJECTIVES: The aim of the present study was to investigate the perceptions of Australian practice nurses on the provision of nutrition care for chronic disease management, including specific nutrition-related activities. METHODS: A cross-sectional online survey was completed by 181 Australian practice nurses in 2013. Descriptive analyses were conducted on each survey item. The survey sample was tested for representation of the Australian practice nurse workforce, and associations between respondents' demographic characteristics and responses to survey items were explored. RESULTS: Almost all practice nurses (89%) felt it was important to address diet whenever they cared for a patient. Over half of practice nurses (61%) were unsure if their practices were effective in increasing patients' compliance with nutritional recommendations. Nearly all practice nurses (98%) perceived further education on nutrition would assist them in their role. CONCLUSION: Practice nurses perceive they have an important role and favourable attitudes towards providing nutrition care; however, further training and education to enhance their self-perceived effectiveness is warranted. Future research should clarify whether an increase in nutrition-focused training results in improved effectiveness of nutrition care provided by practice nurses in terms of patient health outcomes.

Elemental Bioimaging of Sheep Bone and Articular Cartilage After Single Application of Gadolinium-Based Contrast Agents.

BACKGROUND: Gadolinium-based contrast agents (GBCAs) are applied to enhance magnetic resonance imaging. Gadolinium (Gd), a rare earth metal, is used in a chelated form when administered as GBCA to patients. There is an ongoing scientific debate about the clinical significance of Gd retention in tissues after administration of GBCAs. It is known that bone serves as Gd reservoir, but only sparse information on localization of Gd in bone is available. PURPOSE: The aim of this study was to compare Gd tissue concentration and spatial distribution in femoral epiphysis and diaphysis 10 weeks after single-dose injection of linear and macrocyclic GBCAs in a large animal model. MATERIALS AND METHODS: In this prospective animal study, Swiss-Alpine sheep (n = 36; age range, 4-10 years) received a single injection (0.1 mmol/kg) of macrocyclic (gadobutrol, gadoteridol, and gadoterate meglumine), linear (gadodiamide and gadobenate dimeglumine) GBCAs, or saline. Ten weeks after injection, sheep were killed, and femur heads and shafts were harvested. Gadolinium spatial distribution was determined in 1 sample of each treatment group by laser ablation-inductively coupled plasma-mass spectrometry. All bone specimens were analyzed histopathologically. RESULTS: Injection of GBCAs in female Swiss-Alpine sheep (n = 36) resulted in Gd localization at the endosteal and periosteal surface and in a subset of GBCAs additionally at the cement lines and the bone cartilage junction. No histopathological alterations were observed in the investigated tissue specimens. CONCLUSIONS: Ten weeks after single injection of a clinically relevant dose in adult sheep, both linear species of GBCA resulted in considerably higher accumulation than macrocyclic GBCAs. Gadolinium deposits were restricted to distinct bone and cartilage compartments, such as in bone linings, cement lines, and bone cartilage junctions. Tissue histology remained unaffected.

Fluorogenic platinum(IV) complexes as potential predictors for the design of hypoxia-activated platinum(IV) prodrugs.

Hypoxia (low-oxygen) is one of the most common characteristics of solid tumours. Exploiting tumour hypoxia to reductively activate Pt(IV) prodrugs has the potential to deliver toxic Pt(II) selectively and thus overcome the systemic toxicity issues of traditional Pt(II) therapies. However, our current understanding of the behaviour of Pt(IV) prodrugs in hypoxia is limited. Here, we evaluated and compared the aryl carbamate fluorogenic Pt(IV) complexes, CisNap and CarboNap, as well as the previously reported OxaliNap, as potential hypoxia-activated Pt(IV) (HAPt) prodrugs. Low intracellular oxygen concentrations (<0.1%) induced the greatest changes in the respective fluorescence emission channels. However, no correlation between reduction under hypoxic conditions and toxicity was observed, except in the case for CarboNap, which displayed significant hypoxia-dependent toxicity. Other aryl carbamate Pt(IV) derivatives (including non-fluorescent analogues) mirrored these observations, where carboplatin(IV) derivative CarboPhen displayed a hypoxia-selective cytotoxicity similar to that of CarboNap. These findings underscore the need to perform extensive structure activity relationship studies on the cytotoxicity of Pt(IV) complexes under normoxic and hypoxic conditions.

Automated pipeline for nerve fiber selection and g-ratio calculation in optical microscopy: exploring staining protocol variations.

G-ratio is crucial for understanding the nervous system's health and function as it measures the relative myelin thickness around an axon. However, manual measurement is biased and variable, emphasizing the need for an automated and standardized technique. Although deep learning holds promise, current implementations lack clinical relevance and generalizability. This study aimed to develop an automated pipeline for selecting nerve fibers and calculating relevant g-ratio using quality parameters in optical microscopy. Histological sections from the sciatic nerves of 16 female mice were prepared and stained with either p-phenylenediamine (PPD) or toluidine blue (TB). A custom UNet model was trained on a mix of both types of staining to segment the sections based on 7,694 manually delineated nerve fibers. Post-processing excluded non-relevant nerves. Axon diameter, myelin thickness, and g-ratio were computed from the segmentation results and its reliability was assessed using the intraclass correlation coefficient (ICC). Validation was performed on adjacent cuts of the same nerve. Then, morphometrical analyses of both staining techniques were performed. High agreement with the ground truth was shown by the model, with dice scores of 0.86 (axon) and 0.80 (myelin) and pixel-wise accuracy of 0.98 (axon) and 0.94 (myelin). Good inter-device reliability was observed with ICC at 0.87 (g-ratio) and 0.83 (myelin thickness), and an excellent ICC of 0.99 for axon diameter. Although axon diameter significantly differed from the ground truth (p = 0.006), g-ratio (p = 0.098) and myelin thickness (p = 0.877) showed no significant differences. No statistical differences in morphological parameters (g-ratio, myelin thickness, and axon diameter) were found in adjacent cuts of the same nerve (ANOVA p-values: 0.34, 0.34, and 0.39, respectively). Comparing all animals, staining techniques yielded significant differences in mean g-ratio (PPD: 0.48 ± 0.04, TB: 0.50 ± 0.04), myelin thickness (PPD: 0.83 ± 0.28 µm, TB: 0.60 ± 0.20 µm), and axon diameter (PPD: 1.80 ± 0.63 µm, TB: 1.78 ± 0.63 µm). The proposed pipeline automatically selects relevant nerve fibers for g-ratio calculation in optical microscopy. This provides a reliable measurement method and serves as a potential pre-selection approach for large datasets in the context of healthy tissue. It remains to be demonstrated whether this method is applicable to measure g-ratio related with neurological disorders by comparing healthy and pathological tissue. Additionally, our findings emphasize the need for careful interpretation of inter-staining morphological parameters.

Macroscopic dental measures in guinea pigs (Cavia porcellus) fed natural and pelleted diets of different abrasiveness: implications for wear and compensatory growth in a hypselodont species.

The drivers of dental wear and compensatory hypselodont tooth growth are of current research interest. Expanding previous macroscopic dental wear measurements based on microtomographic scans of guinea pigs (Cavia porcellus) fed natural diets, we added diet groups with different predicted drivers of dental wear and analysed how measured variables relate to each other. The teeth of guinea pigs fed either pelleted diets containing external abrasives of various shapes, sizes and percentages (n = 66) or natural whole-leaf diets (n = 36, low-phytolith lucerne or grass or high-phytolith bamboo) were evaluated. The bamboo-fed animals showed the lowest tooth height with deep dentine basins, similar to the pellet-fed animals. Deeper dentine basins generally correlated with higher occlusal surfaces, allowing the hypothesis that changes in the pressure signal due to lower basins could initiate compensatory growth and broadening of the whole tooth surface in hypselodont teeth. Macroscopic dental wear did not categorically differ between whole-leaf or pelleted diets or between diets with internal phytoliths or with external silicate abrasives. Supporting interpretations that tooth wear should be viewed as a response to the biomechanical properties of ingested feed which may or may not be aptly summarized by broad descriptors such as 'whole/pelleted' or 'natural/artificial'.

Elemental bioimaging and transcriptomics reveal unchanged gene expression in mouse cerebellum following a single injection of Gadolinium-based contrast agents.

Gadolinium (Gd) deposition in the brain, first and foremost in the dentate nucleus in the cerebellum, following contrast enhanced MRI, rose awareness of potential adverse effects of gadolinium-based contrast agent (GBCA) administration. According to previous in vitro experiments, a conceivable side-effect of Gd deposition could be an alteration of gene expression. In the current study, we aimed to investigate the influence of GBCA administration on gene expression in the cerebellum of mice using a combination of elemental bioimaging and transcriptomics. In this prospective animal study, three groups of eight mice each were intravenously injected with either linear GBCA gadodiamide, macrocyclic GBCA gadoterate (1 mmol GBCA/kg body weight) or saline (NaCl 0.9%). Animals were euthanized four weeks after injection. Subsequently, Gd quantification via laser ablation-ICP-MS and whole genome gene expression analysis of the cerebellum were performed. Four weeks after single application of GBCAs to 24-31 days old female mice, traces of Gd were detectable in the cerebellum for both, the linear and macrocyclic group. Subsequent transcriptome analysis by RNA sequencing using principal component analysis did not reveal treatment-related clustering. Also differential expression analysis did not reveal any significantly differentially expressed genes between treatments.