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Scandinavian Journal of Trauma,... Aug 2019Traumatic spinal cord injury is a relatively rare injury in Denmark but may result in serious neurological consequences. For decades, prehospital spinal stabilisation...
Traumatic spinal cord injury is a relatively rare injury in Denmark but may result in serious neurological consequences. For decades, prehospital spinal stabilisation with a rigid cervical collar and a hard backboard has been considered to be the most appropriate procedure to prevent secondary spinal cord injuries during patient transportation. However, the procedure has been questioned in recent years, due to the lack of high-quality studies supporting its efficacy. A national interdisciplinary task force was therefore established to provide updated clinical guidelines on prehospital procedures for spinal stabilisation of adult trauma patients in Denmark. The guidelines are based on a systematic review of the literature and grading of the evidence, in addition to a standardised consensus process.This process yielded five main recommendations:A strong recommendation against spinal stabilisation of patients with isolated penetrating trauma; a weak recommendation against the prehospital use of a rigid cervical collar and a hard backboard for ABCDE-stable patients; and a weak recommendation for the use of a vacuum mattress for patient transportation. Finally, our group recommends the use of our clinical algorithm to ensure good clinical practice.
Topics: Adult; Algorithms; Denmark; Evidence-Based Emergency Medicine; Humans; Immobilization; Moving and Lifting Patients; Orthotic Devices; Spinal Cord Injuries; Stretchers; Triage; Wounds, Penetrating
PubMed: 31426850
DOI: 10.1186/s13049-019-0655-x -
Journal of Neurodevelopmental Disorders Jan 2021Research with rodents is crucial for expanding our understanding of genetic and environmental risk factors for neurodevelopmental disorders (NDD). However, there is... (Review)
Review
Research with rodents is crucial for expanding our understanding of genetic and environmental risk factors for neurodevelopmental disorders (NDD). However, there is growing concern about the number of animal studies that are difficult to replicate, potentially undermining the validity of results. These concerns have prompted funding agencies and academic journals to implement more rigorous standards in an effort to increase reproducibility in research. However, these standards fail to address a major source of variability in rodent research brought on by the "litter effect," the fact that rodents from the same litter are phenotypically more similar to one other than rodents from different litters of the same strain. We show that the litter effect accounts for 30-60% of the variability associated with commonly studied phenotypes, including brain, placenta, and body weight. Moreover, we show how failure to control for litter-to-litter variation can mask a phenotype in Chd8 mice that model haploinsufficiency of CHD8, a high-confidence autism gene. Thus, if not properly controlled, the litter effect has the potential to negatively influence rigor and reproducibility of NDD research. While efforts have been made to educate scientists on the importance of controlling for litter effects in previous publications, our analysis of the recent literature (2015-2020) shows that the vast majority of NDD studies focused on genetic risks, including mutant mouse studies, and environmental risks, such as air pollution and valproic acid exposure, do not correct for litter effects or report information on the number of litters used. We outline best practices to help scientists minimize the impact of litter-to-litter variability and to enhance rigor and reproducibility in future NDD studies using rodent models.
Topics: Animals; Female; Haploinsufficiency; Mice; Neurodevelopmental Disorders; Phenotype; Pregnancy; Reproducibility of Results
PubMed: 33397279
DOI: 10.1186/s11689-020-09353-y -
BMC Microbiology May 2023Decomposition of plant litter is a key driver of carbon and nutrient cycling in terrestrial ecosystems. Mixing litters of different plant species may alter the...
BACKGROUND
Decomposition of plant litter is a key driver of carbon and nutrient cycling in terrestrial ecosystems. Mixing litters of different plant species may alter the decomposition rate, but its effect on the microbial decomposer community in plant litter is not fully understood. Here, we tested the effects of mixing with maize (Zea mays L.) and soybean [Glycine max (Linn.) Merr.] stalk litters on the decomposition and microbial decomposer communities of common bean (Phaseolus vulgaris L.) root litter at the early decomposition stage in a litterbag experiment.
RESULTS
Mixing with maize stalk litter, soybean stalk litter, and both of these litters increased the decomposition rate of common bean root litter at 56 day but not 14 day after incubation. Litter mixing also increased the decomposition rate of the whole liter mixture at 56 day after incubation. Amplicon sequencing found that litter mixing altered the composition of bacterial (at 56 day after incubation) and fungal communities (at both 14 and 56 day after incubation) in common bean root litter. Litter mixing increased the abundance and alpha diversity of fungal communities in common bean root litter at 56 day after incubation. Particularly, litter mixing stimulated certain microbial taxa, such as Fusarium, Aspergillus and Stachybotrys spp. In addition, a pot experiment with adding litters in the soil showed that litter mixing promoted growth of common bean seedlings and increased soil nitrogen and phosphorus contents.
CONCLUSIONS
This study showed that litter mixing can promote the decomposition rate and cause shifts in microbial decomposer communities, which may positively affect crop growth.
Topics: Ecosystem; Phaseolus; Soil Microbiology; Microbiota; Bacteria; Plants; Soil; Glycine max; Plant Leaves
PubMed: 37217839
DOI: 10.1186/s12866-023-02871-4 -
Frontiers in Veterinary Science 2022The current study evaluated interactions between farrowing duration and litter size on the level of asphyxia, vitality, percentage of stillbirth, and pre-weaning...
The current study evaluated interactions between farrowing duration and litter size on the level of asphyxia, vitality, percentage of stillbirth, and pre-weaning mortality of piglets. Farrowing duration was measured in 159 crossbred gilts and sows (Yorkshire × Dutch Landrace). Litter size ranged between 12 and 21 piglets. Blood acid-base parameters in umbilical cord blood and vitality scores of piglets were determined immediately after birth. Number of piglets born alive and stillborn as well as individual piglet weights at birth were recorded. Pre-weaning mortality (excluding stillbirth) was determined throughout lactation. Litter size as well as farrowing duration were categorized to evaluate the interaction between the two. There tended to be an interaction between litter size and farrowing duration for pre-weaning mortality ( = 0.10). In small litters (12-15 piglets), a prolonged farrowing duration (>250 min) tended to increase pre-weaning mortality compared with a short (<150 min) and medium farrowing duration (150-250 min), while for large litters (19-21 piglets), a medium to long farrowing duration tended to decrease pre-weaning mortality. No other interactions between litter size and farrowing duration were found. Piglets within large litters showed a higher umbilical cord lactate level ( < 0.01), lower average vitality score ( = 0.01), and a higher stillborn percentage ( < 0.01) compared with piglets within medium size (16-18 piglets) and small litters. Each additional piglet born to a litter linearly decreased average piglet birth weight (17.6 g, < 0.01), increased farrowing duration (11 min, < 0.01), and increased stillbirth (0.5%, = 0.04). A medium farrowing duration resulted in a lower stillborn percentage compared with a short or prolonged farrowing duration, suggesting that farrowing duration might have an optimum. When analyzed linearly, stillborn percentage increased with 1.85% per every 100 min ( < 0.01) of farrowing duration. It can be concluded that both litter size and farrowing duration affect stillborn percentage, but independent from each other. However, these two factors tended to interact regarding pre-weaning mortality, suggesting that setting a certain threshold for maximal farrowing duration should be taken with care, because this appears to depend on litter size.
PubMed: 35529832
DOI: 10.3389/fvets.2022.836202 -
Genes Dec 2021INGA FOOD S. A., as a Spanish company that produces and commercializes fattened pigs, has produced a hybrid Iberian sow called CASTÚA by crossing the Retinto and...
INGA FOOD S. A., as a Spanish company that produces and commercializes fattened pigs, has produced a hybrid Iberian sow called CASTÚA by crossing the Retinto and Entrepelado varieties. The selection of the parental populations is based on selection criteria calculated from purebred information, under the assumption that the genetic correlation between purebred and crossbred performance is high; however, these correlations can be less than one because of a GxE interaction or the presence of non-additive genetic effects. This study estimated the additive and dominance variances of the purebred and crossbred populations for litter size, and calculated the additive genetic correlations between the purebred and crossbred performances. The dataset consisted of 2030 litters from the Entrepelado population, 1977 litters from the Retinto population, and 1958 litters from the crossbred population. The individuals were genotyped with a GeneSeek GGP Porcine70K HDchip. The model of analysis was a 'biological' multivariate mixed model that included additive and dominance SNP effects. The estimates of the additive genotypic variance for the total number born (TNB) were 0.248, 0.282 and 0.546 for the Entrepelado, Retinto and Crossbred populations, respectively. The estimates of the dominance genotypic variances were 0.177, 0.172 and 0.262 for the Entrepelado, Retinto and Crossbred populations. The results for the number born alive (NBA) were similar. The genetic correlations between the purebred and crossbred performance for TNB and NBA-between the brackets-were 0.663 in the Entrepelado and 0.881 in Retinto poplulations. After backsolving to obtain estimates of the SNP effects, the additive genetic variance associated with genomic regions containing 30 SNPs was estimated, and we identified four genomic regions that each explained > 2% of the additive genetic variance in chromosomes (SSC) 6, 8 and 12: one region in SSC6, two regions in SSC8, and one region in SSC12.
Topics: Animals; Crosses, Genetic; Genome; Genomics; Genotype; Hybridization, Genetic; Litter Size; Models, Genetic; Phenotype; Polymorphism, Single Nucleotide; Swine
PubMed: 35052355
DOI: 10.3390/genes13010012 -
NeuroImage Apr 2023Our current understanding of litter variability in neurodevelopmental studies using mice may limit translation of neuroscientific findings. Higher variance of measures...
Our current understanding of litter variability in neurodevelopmental studies using mice may limit translation of neuroscientific findings. Higher variance of measures across litters than within, often termed intra-litter likeness, may be attributable to both pre- and postnatal environment. This study aimed to assess the litter-effect within behavioral assessments (2 timepoints) and anatomy using T1-weighted magnetic resonance images across 72 brain region volumes (4 timepoints) (36 C57bl/6J inbred mice; 7 litters: 19F/17M). Between-litter comparisons of brain and behavioral measures and their associations were evaluated using univariate and multivariate techniques. A power analysis using simulation methods was then performed on modeled neurodevelopment and to evaluate trade-offs between number-of-litters, number-of-mice-per-litter, and sample size. Our results show litter-specific developmental effects, from the adolescent period to adulthood for brain structure volumes and behaviors, and for their associations in adulthood. Our power simulation analysis suggests increasing the number-of-litters in experimental designs to achieve the smallest total sample size necessary for detecting different rates of change in specific brain regions. Our results demonstrate how litter-specific effects may influence development and that increasing the litters to the total sample size ratio should be strongly considered when designing neurodevelopmental studies.
Topics: Pregnancy; Female; Animals; Mice; Litter Size; Computer Simulation; Mice, Inbred C57BL
PubMed: 36681136
DOI: 10.1016/j.neuroimage.2023.119888 -
Endocrinology Jul 2016The power of animal models is derived from the ability to control experimental variables so that observed effects may be unequivocally attributed to the factor that was... (Review)
Review
The power of animal models is derived from the ability to control experimental variables so that observed effects may be unequivocally attributed to the factor that was changed. One variable that is difficult to control in animal experiments is the number and composition of offspring in a litter. To account for this variability, artificial equalization of the number of offspring in a litter (culling) is often used. The rationale for culling, however, has always been controversial. The Developmental Origins of Health and Disease concept provides a new context to evaluate the pros and cons of culling in laboratory animal studies, especially in the context of endocrine-disrupting chemicals. Emerging evidence indicates that culling, especially of large litters, can drastically change the feeding status of a pup, which can result in compensatory growth with long-term consequences for the animal, including increased risk of cardio-metabolic diseases. Similarly, culling of litters to intentionally bias sex ratios can alter the animal's behavior and physiology, with effects observed on a wide range of outcomes. Thus, in an attempt to control for variability in developmental rates, culling introduces an uncontrolled or confounding variable, which itself may affect a broad spectrum of health-related consequences. Variabilities in culling protocols could be responsible for differences in responses to endocrine-disrupting chemicals reported across studies. Because litter sex composition and size are vectors that can influence both prenatal and postnatal growth, they are essential considerations for the interpretation of results from laboratory animal studies.
Topics: Animals; Behavior, Animal; Endocrine Disruptors; Female; Litter Size; Models, Animal; Reproduction; Research Design
PubMed: 27175970
DOI: 10.1210/en.2016-1145 -
Animal : An International Journal of... Jul 2023Survival of growing pigs through to slaughter age is not only a key driver of profitability but also has implications for animal welfare. Changing preweaning mortality... (Review)
Review
Survival of growing pigs through to slaughter age is not only a key driver of profitability but also has implications for animal welfare. Changing preweaning mortality by over 3% gives a similar change in profit per pig as changing postweaning mortality by 1%. There is significant scope to improve both traits through management and breeding to improve survival. The aim of this literature review was to explore the relationship between litter size and piglet birthweight and the detrimental impact this negative association has had on pig survival, along with genetic strategies that have been implemented in breeding programmes. It is suggested that the primary effect of litter size on mortality was indirect, through the effects of litter size on individual piglet birthweights. The circumstances affecting the litter a piglet was born into were the most important for determining the birthweight of individual piglets, rather than the genetic make-up of the individual piglet itself. Therefore, breeding programmes should include the average piglet birthweight of a litter (i.e., a sow trait) rather than individual piglet birthweight to maintain the weight of piglets at birth. The relative weighting of litter size and average piglet birthweight should be done in a manner that avoids selecting heavy pigs from small litters. Additional genetic strategies to improve survival include survival at the litter level, or survival of individual piglets or enhanced through the use of genomic information. At the litter level, litter size at day 5 and weaning can be considered as sow traits, but the use of these traits depends on the recording environment. At the individual piglet level, pre- and postweaning survival can be recorded as 0/1 traits and analysed directly. Although heritabilities are low for all these traits, genetic improvements can be made. For preweaning survival, the genes of the nurse sow are more important than the genes of the individual piglet. The nurse sow model captures both the lactation and gestation effects, and the information obtained when piglets born from different litters are reared together. However, once a piglet is weaned, its own genes became more important for the expression of postweaning mortality outcomes. Finally, for a successful selection programme, combining the average piglet birthweight at the litter level and mortality data based on individual piglet records (not solely birthweight) might yield the best response in piglet survival.
PubMed: 37574357
DOI: 10.1016/j.animal.2023.100914 -
Nutrients May 2022Overfeeding during lactation has a deleterious impact on the baby's health throughout life. In humans, early overnutrition has been associated with higher susceptibility... (Review)
Review
Overfeeding during lactation has a deleterious impact on the baby's health throughout life. In humans, early overnutrition has been associated with higher susceptibility to obesity and metabolic disorders in childhood and adulthood. In rodents, using a rodent litter size reduction model (small litter) to mimic early overfeeding, the same metabolic profile has been described. Therefore, the rodent small litter model is an efficient tool to investigate the adaptive mechanisms involved in obesogenesis. Besides central and metabolic dysfunctions, studies have pointed to the contribution of the endocrine system to the small litter phenotype. Hormones, especially leptin, insulin, and adrenal hormones, have been associated with satiety, glucose homeostasis, and adipogenesis, while hypothyroidism impairs energy metabolism, favoring obesity. Behavioral modifications, hepatic metabolism changes, and reproductive dysfunctions have also been reported. In this review, we update these findings, highlighting the interaction of early nutrition and the adaptive features of the endocrine system. We also report the sex-related differences and epigenetic mechanisms. This model highlights the intense plasticity during lactation triggering many adaptive responses, which are the basis of the developmental origins of health and disease (DOHaD) concept. Our review demonstrates the complexity of the adaptive mechanisms involved in the obesity phenotype promoted by early overnutrition, reinforcing the necessity of adequate nutritional habits during lactation.
Topics: Adult; Animals; Female; Humans; Lactation; Litter Size; Metabolic Diseases; Obesity; Overnutrition; Pregnancy
PubMed: 35631188
DOI: 10.3390/nu14102045 -
Physiology & Behavior Oct 2018Most maternal caregiving behaviors change across lactation to match the developmental needs of the continuously aging offspring. However, it is mostly unknown whether...
Most maternal caregiving behaviors change across lactation to match the developmental needs of the continuously aging offspring. However, it is mostly unknown whether the dams' postpartum stage or litter age is the primary driving force of these changes. In this study, postnatal day 1 and 8 litters were cross-fostered or in-fostered to postpartum day 1 or 8 dams. Five days later, undisturbed observations of maternal caregiving behaviors were performed on the subsequent two days. We found a main effect of dams' postpartum stage on the frequency that mothers spent with the pups and displayed erect postures over them (hovering over and kyphosis), although it was mostly driven by an interaction between postpartum stage and litter age: early-postpartum dams were in contact with younger litters and in erect postures more often with younger litters compared to later-postpartum dams with younger litters. Additionally, there was an interaction between postpartum stage and litter age on the litter weights because older litters living with later-postpartum dams were heavier than older litters living with early-postpartum dams. There was also an interaction between postpartum stage and litter age on the dams' bodyweight, with early-postpartum dams living with younger litters weighing the least and later-postpartum dams living with younger litters weighing the most. Because activity of the neuropeptide, orexin, within the medial preoptic area (mPOA) has been implicated in maternal nursing and other caregiving behaviors, we measured mPOA levels of orexin-A but it was not affected by postpartum stage or litter age (nor was there an interaction). However, high orexin-A was negatively associated with the frequency of contact with pups and the display of erect postures. These results indicate that changes in caregiving across lactation are driven by endogenous factors in the dams, age-related cues they receive from offspring, and interactions between these factors.
Topics: Age Factors; Animals; Animals, Newborn; Female; Maternal Behavior; Orexins; Postpartum Period; Preoptic Area
PubMed: 29928888
DOI: 10.1016/j.physbeh.2018.06.025