The prevalence of genital injuries in post-pubertal females presenting for forensic examination after reported sexual violence: a systematic review

BACKGROUND

Sexual violence is a prevalent issue in contemporary society requiring a robust forensic healthcare response. It is critically important that forensic examiners put clinical examination findings into an appropriate evidence-based context. The presence of genital injuries has been shown to increase the likelihood of successful criminal prosecution and report the crime. However, the reported rates of genital injury vary widely in published studies.

AIMS AND OBJECTIVES

We aim to critically evaluate and synthesize existing literature on the prevalence of genital injuries in post-pubertal females, examined following sexual violence, with a view to describing the prevalence and characteristics of genital injuries as well as the range of forensic practices employed.

METHODS

Three online databases (PubMed, Embase, and Scopus) were systematically searched with key terms.

RESULTS

Of the 1224 studies screened, 141 full-text publications met the inclusion criteria. Reported injury prevalence rates varied widely. Details pertaining to forensic examinations included in each study, such as grade of the examiner, type of examination, location of examination, and time interval from assault to examination also varied widely. Injury prevalence was highest in studies where enhanced visualization techniques were utilized.

CONCLUSIONS

This systematic review demonstrates that there is no universally agreed standard for documenting genital injuries in cases of sexual violence and highlights the need for standardized approaches and guidelines for assessing, documenting, and reporting these injuries. The review provides robust evidence to support a call for establishing consistent context, terminology, classification systems, and data collection methods to improve the comparability and reliability of future research findings.

Parity modulates impact of BMI and gestational weight gain on gut microbiota in human pregnancy

Dysregulation of maternal adaptations to pregnancy due to high pre-pregnancy BMI (pBMI) or excess gestational weight gain (GWG) is associated with worsened health outcomes for mothers and children. Whether the gut microbiome contributes to these adaptations is unclear. We longitudinally investigated the impact of pBMI and GWG on the pregnant gut microbiome. We show that the gut microbiota of participants with higher pBMI changed less over the course of pregnancy in primiparous but not multiparous participants. This suggests that previous pregnancies may have persistent impacts on maternal adaptations to pregnancy. This ecological memory appears to be passed on to the next generation, as parity modulated the impact of maternal GWG on the infant gut microbiome. This work supports a role of the gut microbiome in maternal adaptations to pregnancy and highlights the need for longitudinal sampling and accounting for parity as key considerations for studies of the microbiome in pregnancy and infants. Understanding how these factors contribute to and shape maternal health is essential for the development of interventions impacting the microbiome, including pre/probiotics.

Intestinal permeability and peripheral immune cell composition are altered by pregnancy and adiposity at mid- and late-gestation in the mouse

It is clear that the gastrointestinal tract influences metabolism and immune function. Most studies to date have used male test subjects, with a focus on effects of obesity and dietary challenges. Despite significant physiological maternal adaptations that occur across gestation, relatively few studies have examined pregnancy-related gut function. Moreover, it remains unknown how pregnancy and diet can interact to alter intestinal barrier function. In this study, we investigated the impacts of pregnancy and adiposity on maternal intestinal epithelium morphology, in vivo intestinal permeability, and peripheral blood immunophenotype, using control (CTL) and high-fat (HF) fed non-pregnant female mice and pregnant mice at mid- (embryonic day (E)14.5) and late (E18.5) gestation. We found that small intestine length increased between non-pregnant mice and dams at late-gestation, but ileum villus length, and ileum and colon crypt depths and goblet cell numbers remained similar. Compared to CTL-fed mice, HF-fed mice had reduced small intestine length, ileum crypt depth and villus length. Goblet cell numbers were only consistently reduced in HF-fed non-pregnant mice. Pregnancy increased in vivo gut permeability, with a greater effect at mid- versus late-gestation. Non-pregnant HF-fed mice had greater gut permeability, and permeability was also increased in HF-fed pregnant dams at mid but not late-gestation. The impaired maternal gut barrier in HF-fed dams at mid-gestation coincided with changes in maternal blood and bone marrow immune cell composition, including an expansion of circulating inflammatory Ly6Chigh monocytes. In summary, pregnancy has temporal effects on maternal intestinal structure and barrier function, and on peripheral immunophenotype, which are further modified by HF diet-induced maternal adiposity. Maternal adaptations in pregnancy are thus vulnerable to excess maternal adiposity, which may both affect maternal and child health.

Resilience in adolescence during the COVID-19 crisis in Canada

BACKGROUND

The COVID-19 pandemic constitutes a social crisis that will have long-term health consequences for much of the global population, especially for adolescents. Adolescents are triply affected as they: 1) are experiencing its immediate, direct effects, 2) will carry forward health habits they develop now into adulthood, and 3) as future parents, will shape the early life health of the next generation. It is therefore imperative to assess how the pandemic is influencing adolescent wellbeing, identify sources of resilience, and outline strategies for attenuating its negative impacts.

METHODS

We report the results of longitudinal analyses of qualitative data from 28 focus group discussions (FGDs) with 39 Canadian adolescents and of cross-sectional analyses of survey data from 482 Canadian adolescents gathered between September 2020 and August 2021. FGD participants and survey respondents reported on their: socio-demographic characteristics; mental health and wellbeing before and during the pandemic; pre- and during-pandemic health behaviours; experiences living through a crisis; current perceptions of their school, work, social, media, and governmental environments; and ideas about pandemic coping and mutual aid. We plotted themes emerging from FGDs along a pandemic timeline, noting socio-demographic variations. Following assessment for internal reliability and dimension reduction, quantitative health/wellbeing indicators were analyzed as functions of composite socio-demographic, health-behavioural, and health-environmental indicators.

RESULTS

Our mixed methods analyses indicate that adolescents faced considerable mental and physical health challenges due to the pandemic, and were generally in poorer health than expected in non-crisis times. Nevertheless, some participants showed significantly better outcomes than others, specifically those who: got more exercise; slept better; were food secure; had clearer routines; spent more time in nature, deep in-person social relationships, and leisure; and spent less time on social media.

CONCLUSIONS

Support for youth during times of crisis is essential to future population health because adolescence is a period in the life course which shapes the health behaviours, socio-economic capacities, and neurophysiology of these future parents/carers and leaders. Efforts to promote resilience in adolescents should leverage the factors identified above: helping them find structure and senses of purpose through strong social connections, well-supported work and leisure environments, and opportunities to engage with nature.

Symposium review: Fueling appetite: Nutrient metabolism and the control of feed intake

Conceptual models developed over the past century describe 2 key constraints to feed intake (FI) of healthy animals: gut capacity and metabolic demand. Evidence that greater energy demands (e.g., greater milk production) drive a corresponding increase in caloric intake led to the dominant concept that animals "eat to energy requirements." Although this model provides reasonable initial estimates of FI, it lacks a proposed physiological basis for the control system, does not consider nutrient constraints beyond energy, and fails to explain differential energy intake responses to different fuels. To address these gaps, research has focused on mechanisms for sensing nutrient availability and providing feedback to hypothalamic centers that integrate signals to control feeding behavior. The elimination of FI response to certain nutrients by vagotomy suggests that peripheral tissues play a role in nutrient sensing. These findings and the central role of the liver in metabolic flux led to the development of the hepatic oxidation theory (HOT). According to the HOT, liver energy charge is the regulated variable that induces dietary intake changes and consequently affects whole-body energy balance. Evidence in support of HOT includes associations between hepatic energy charge and meal patterns, increased FI in response to phosphate trapping, and reduced FI in response to phosphate loading. In accordance with the HOT, infusion studies in dairy cattle have consistently demonstrated that providing fuels that either oxidize or stimulate oxidation in the liver decreases FI and energy intake to a greater extent than fuels that bypass the liver. Importantly, this holds true for glucose, which is readily oxidized by nerve cells, but is rarely taken up by the bovine liver. Although the brain integrates multiple signals including those related to gastric distention and illness, the HOT provides a physiological framework for understanding the dominant role the liver likely plays in sensing short-term energy status. Understanding this model provides insights into how to use or bypass the regulatory system to manage FI of animals.

Influence of lactation stage on heat production and macronutrient oxidation in dairy cows during a 24-hour fasting period

Understanding nutrient utilization and partitioning is essential for advancing the efficiency of dairy cattle. Our objective was to determine if dairy cows exposed to a 24-h fasting period differ in heat production (HP) and macronutrient oxidation at different stages of lactation. Twelve primiparous, lactating German Holstein dairy cows were used in a longitudinal study design spanning from 2013 to 2014. Dairy cows were housed in respiration chambers during 3 stages of the lactation cycle: early (mean ± SD; 28.8 ± 6.42 d), mid- (89.4 ± 4.52 d), and late (293 ± 7.76 d) lactation. Individual CO₂, O₂, and CH₄ gas exchanges were measured every 6 min for two 24-h periods, an ad libitum period and fasting period (RES). Blood was sampled at the start and end of the RES period. Gas measurements were used to calculate HP, net carbohydrate oxidation (COX), and net fat oxidation (FOX). Measurements were corrected with metabolic BW (kg of BW^0.75; cBW). The RES period for each stage of lactation was further subdivided into the start (RES_start) and end (RES_end) by averaging the first and last 2 h of the RES period. The net change was calculated as RES_end - RES_start. All energy variables differed among lactation stage within the RES period except for HP/cBW. As expected, COX, COX/cBW, COX/HP, HP, and HP/cBW, were greater at the RES_start compared with RES_end, whereas FOX, FOX/cBW, and FOX/HP were greater at the RES_end except for FOX and FOX/cBW during mid lactation, which was only a tendency for a difference. The net change for COX, COX/cBW, HP, HP/cBW, and FOX/cBW did not differ among stages of lactation. Despite detecting a tendency for a difference among stage of lactation for FOX, pairwise analysis revealed no differences. Plasma triglyceride, urea, and nonesterified fatty acid concentrations were greater at RES_end than RES_start. The net change for plasma glucose, urea, β-hydroxybutyrate, and nonesterified fatty acid concentrations were greater in early than late lactation. Our results demonstrate that despite differences in absolute measurements of energy variables and plasma metabolites, the change in whole-body macronutrient oxidation and HP as cows' transition from a fed-like state to a starvation-like state during a 24-h fasting period is consistent throughout lactation.

Utility of Environmental Complexity as a Predictor of Alzheimer's Disease Diagnosis: A Big-Data Machine Learning Approach

BACKGROUND

Rural-urban differences and spatial navigation deficits have received much attention in Alzheimer's Disease research. While individual environmental and neighborhood factors have been independently investigated, their integrative, multifactorial effects on Alzheimer's diagnosis have not. Here we explore this "environmental complexity" for predictive power in classifying Alzheimer's from cognitively-normal status.

METHODS

We utilized data from the National Alzheimer's Coordinating Center (NACC) uniform data set containing annual visits since 2005 and selected individuals with multiple visits and who remained in their zipcode (N = 22,553). We georeferenced each subject with 3-digit zipcodes of their residences since entering the program. We calculated environmental complexity measures using geospatial tools from street networks and landmarks for spatial navigation in subjects' zipcode zones. Zipcode zones were grouped into two cognitive classes (Cognitively-Normal and Alzheimer's-inclined) based on the ratios of AD and dementia subjects to all subjects in an individual zipcode zone. We randomly selected 80% of the data to train a neural network classifier model on environmental complexity measures to predict the cognitive class for each zone, controlling for salient demographic variables. The remaining 20% served as the test set for performance evaluation.

RESULTS

Our proposed model reached excellent classification ability on the testing data: 83.87% accuracy, 95.23% precision, 83.33% recall, and 0.8889 F1-score (F1-score=1 for perfect prediction). The most salient features of "Alzheimer's-inclined" zipcode zones included longer street-length average, higher circuity, and slightly fewer points of interest. Most "cognitively-normal" zipcode zones appeared in or near urban areas with high environmental complexity measures.

CONCLUSION

Environmental complexity, reflected in frequency and density of street networks and landmarks features, predicted with high precision the cognitive status of 3-digit zipcode zones based on the etiologic diagnoses and observed cognitive impairment of NACC subjects residing in these zones. The zipcode zones vary widely in size (1.6 km2 to 35,241 km2), and large zipcode zones suffer high spatial heterogeneity. Other proven AD risk factors, such as PM2.5, disperse across zones, and so do individual's activities, leading to spatial uncertainty. Nevertheless, the model classifies diagnosis well, establishing the need for prospective experiments to quantify effects of environmental complexity on Alzheimer's development.

Questioning the fetal microbiome illustrates pitfalls of low-biomass microbial studies

Whether the human fetus and the prenatal intrauterine environment (amniotic fluid and placenta) are stably colonized by microbial communities in a healthy pregnancy remains a subject of debate. Here we evaluate recent studies that characterized microbial populations in human fetuses from the perspectives of reproductive biology, microbial ecology, bioinformatics, immunology, clinical microbiology and gnotobiology, and assess possible mechanisms by which the fetus might interact with microorganisms. Our analysis indicates that the detected microbial signals are likely the result of contamination during the clinical procedures to obtain fetal samples or during DNA extraction and DNA sequencing. Furthermore, the existence of live and replicating microbial populations in healthy fetal tissues is not compatible with fundamental concepts of immunology, clinical microbiology and the derivation of germ-free mammals. These conclusions are important to our understanding of human immune development and illustrate common pitfalls in the microbial analyses of many other low-biomass environments. The pursuit of a fetal microbiome serves as a cautionary example of the challenges of sequence-based microbiome studies when biomass is low or absent, and emphasizes the need for a trans-disciplinary approach that goes beyond contamination controls by also incorporating biological, ecological and mechanistic concepts.

Paternal obesity induces placental hypoxia and sex-specific impairments in placental vascularization and offspring metabolism

Paternal obesity predisposes offspring to metabolic dysfunction, but the underlying mechanisms remain unclear. We investigated whether this metabolic dysfunction is associated with changes in placental vascular development and is fueled by endoplasmic reticulum (ER) stress-mediated changes in fetal hepatic development. We also determined whether paternal obesity indirectly affects the in utero environment by disrupting maternal metabolic adaptations to pregnancy. Male mice fed a standard chow or high fat diet (60%kcal fat) for 8–10 weeks were time-mated with female mice to generate pregnancies and offspring. Glucose tolerance was evaluated in dams at mid-gestation (embryonic day (E) 14.5) and late gestation (E18.5). Hypoxia, angiogenesis, endocrine function, macronutrient transport, and ER stress markers were evaluated in E14.5 and E18.5 placentae and/or fetal livers. Maternal glucose tolerance was assessed at E14.5 and E18.5. Metabolic parameters were assessed in offspring at ~60 days of age. Paternal obesity did not alter maternal glucose tolerance but induced placental hypoxia and altered placental angiogenic markers, with the most pronounced effects in female placentae. Paternal obesity increased ER stress-related protein levels (ATF6 and PERK) in the fetal liver and altered hepatic expression of gluconeogenic factors at E18.5. Offspring of obese fathers were glucose intolerant and had impaired whole-body energy metabolism, with more pronounced effects in female offspring. Metabolic deficits in offspring due to paternal obesity may be mediated by sex-specific changes in placental vessel structure and integrity that contribute to placental hypoxia and may lead to poor fetal oxygenation and impairments in fetal metabolic signaling pathways in the liver.

Differences in net fat oxidation, heat production, and liver mitochondrial DNA copy numbers between high and low feed-efficient dairy cows

Improving feed utilization efficiency in dairy cattle could have positive economic and environmental effects that would support the sustainability of the dairy industry. Identifying key differences in metabolism between high and low feed-efficient animals is vital to enhancing feed conversion efficiency. Therefore, our objectives were (1) to determine whether cows grouped by either high or low feed efficiency have measurable differences in net fat and carbohydrate metabolism that account for differences in heat production (HP), and if so, whether these differences also exists under conditions of feed withdrawal when the effect of feeding on HP is minimized, and (2) to determine whether the abundance of mitochondria in the liver can be related to the high or low feed-efficient groups. Ten dairy cows from a herd of 15 (parity = 2) were retrospectively grouped into either a high (H) or a low (L) feed-efficient group (n = 5 per group) based on weekly energy-corrected milk (ECM) divided by dry mater intake (DMI) from wk 4 through 30 of lactation. Livers were biopsied at wk -4, 2, and 12, and blood was sampled weekly from wk -3 to 12 relative to parturition. Blood was subset to be analyzed for the transition period (wk -3 to 3) and from wk 4 to 12. In wk 5.70 ± 0.82 (mean ± SD) postpartum (PP), cows spent 2 d in respiration chambers (RC), in which CO₂, O₂, and CH₄ gases were measured every 6 min for 24 h. Fatty acid oxidation (FOX), carbohydrate oxidation (COX), metabolic respiratory quotient (RQ), and HP were calculated from gas measurements for 23 h. Cows were fed ad libitum (AD-LIB) on d 1 and had feed withdrawn (RES, restricted diet) on d 2. Additional blood samples were taken at the end of the AD-LIB and RES feeding periods in the RC. During wk 4 to 30 PP, H had greater DMI/kg of metabolic body weight (BW^0.75), ECM per kilogram of BW^0.75 yield, and ECM/DMI ratio, compared with L, but a lower body condition score between wk 4 and 12 PP. In the RC period, we detected no differences in BW, DMI, or milk yield between groups. We also detected no significant group or group by feeding period interactions for plasma metabolites except for Revised Quantitative Insulin Sensitivity Check Index, which tended to have a group by feeding period interaction. The H group had lower HP and HP per kilogram of BW^0.75 compared with L. Additionally, H had lower FOX and FOX per kilogram of BW^0.75 compared with L during the AD-LIB period. Methane, CH₄ per kilogram of BW^0.75, and CH₄ per kilogram of milk yield were lower in H compared with L, but, when adjusted for DMI, CH₄/DMI did not differ between groups, nor did HP/DMI. Relative mitochondrial DNA copy numbers in the liver were lower in the L than in the H group. These results suggest that lower feed efficiency in dairy cows may result from fewer mitochondria per liver cell as well as a greater whole-body HP, which likely partially results from higher net fat oxidation.

Exposure to high fructose corn syrup during adolescence in the mouse alters hepatic metabolism and the microbiome in a sex-specific manner

KEY POINTS

The prevalence of obesity and non-alcoholic fatty liver disease in children is dramatically increasing at the same time as consumption of foods with a high sugar content. Intake of high fructose corn syrup (HFCS) is a possible aetiology as it is thought to be more lipogenic than glucose. In a mouse model, HFCS intake during adolescence increased fat mass and hepatic lipid levels in male and female mice. However, only males showed impaired glucose tolerance. Multiple metabolites including lipids, bile acids, carbohydrates and amino acids were altered in liver in a sex-specific manner at 6 weeks of age. Some of these changes were also present in adulthood even though HFCS exposure ended at 6 weeks. HFCS significantly altered the gut microbiome, which was associated with changes in key microbial metabolites. These results suggest that HFCS intake during adolescence has profound metabolic changes that are linked to changes in the microbiome and these changes are sex-specific.

ABSTRACT

The rapid increase in obesity, diabetes and fatty liver disease in children over the past 20 years has been linked to increased consumption of high fructose corn syrup (HFCS), making it essential to determine the short- and long-term effects of HFCS during this vulnerable developmental window. We hypothesized that HFCS exposure during adolescence significantly impairs hepatic metabolic signalling pathways and alters gut microbial composition, contributing to changes in energy metabolism with sex-specific effects. C57bl/6J mice with free access to HFCS during adolescence (3-6 weeks of age) underwent glucose tolerance and body composition testing and hepatic metabolomics, gene expression and triglyceride content analysis at 6 and 30 weeks of age (n = 6-8 per sex). At 6 weeks HFCS-exposed mice had significant increases in fat mass, glucose intolerance, hepatic triglycerides (females) and de novo lipogenesis gene expression (ACC, DGAT, FAS, ChREBP, SCD, SREBP, CPT and PPARα) with sex-specific effects. At 30 weeks, HFCS-exposed mice also had abnormalities in glucose tolerance (males) and fat mass (females). HFCS exposure enriched carbohydrate, amino acid, long chain fatty acid and secondary bile acid metabolism at 6 weeks with changes in secondary bile metabolism at 6 and 30 weeks. Microbiome studies performed immediately before and after HFCS exposure identified profound shifts of microbial species in male mice only. In summary, short-term HFCS exposure during adolescence induces fatty liver, alters important metabolic pathways, some of which continue to be altered in adulthood, and changes the microbiome in a sex-specific manner.

Effect of uncouplers of oxidative phosphorylation on metabolism of propionate in liver explants from dairy cows

Our objective was to determine the effects of uncouplers of oxidative phosphorylation on the metabolism of propionate in liver tissue of dairy cows in the postpartum period. A total of 8 primiparous dairy cows were biopsied for liver tissue explants in 2 block-design experiments. Cows were 5.9 ± 2.8 (mean ± SD) days in milk, and the 2 experiments were run concurrently. Treatments for experiment 1 were 10 μM 2,4-dinitrophenol methyl ether (DNPME) or propylene carbonate (vehicle control). Treatments for experiment 2 were 5 mM sodium salicylate (SAL) or no treatment (control). Explants were incubated in 2.5 mM [¹³C₃]propionate with treatments and terminated after 0.5, 15, and 60 min of exposure to tracer. Treatment with DNPME had no effects on measured metabolites compared with control. Treatment with SAL increased total ¹³C% enrichment of succinate (3.03 vs. 2.45%), but tended to decrease total ¹³C% enrichment of fumarate (2.86 vs. 3.10%) and decreased total ¹³C% enrichment of malate (3.96 vs. 4.58%) compared with the control. Treatment with DNPME appeared to have no effects on hepatic propionate metabolism, and treatment with SAL may impair the succinate dehydrogenase reaction.

Effects of propionate concentration on short-term metabolism in liver explants from dairy cows in the postpartum period

Our objective was to determine the temporal effects of increasing supply of propionate on propionate metabolism in liver tissue of dairy cows in the postpartum (PP) period. A total of 6 dairy cows [primiparous: n = 3, 9.00 ± 1.00 d PP (mean ± SD) and multiparous: n = 3; 4.67 ± 1.15 d PP] were biopsied for liver explants in a block-design experiment. Explants were treated with 3 concentrations of [¹³C₃]sodium propionate of 1, 2, or 4 mM. Explants were incubated in 2 mL of Medium 199 supplemented with 1% BSA, 0.6 mM oleic acid, 2 mM sodium l-lactate, 0.2 mM sodium pyruvate, and 0.5 mMl-glutamine at 38°C and sampled at 0.5, 15, and 60 min. Increasing the concentration of [¹³C₃]propionate increased total ¹³C% enrichment of propionyl coenzyme A (CoA), succinate, fumarate, malate, and citrate with time. Concentration of propionate did not affect total ¹³C% enrichment of hepatic glucose or acetyl CoA, but total ¹³C% enrichment increased with time for hepatic glucose. The ¹³C labeling from propionate was incorporated into acetyl CoA, but increased concentrations of propionate did not result in greater labeling of acetyl CoA. However, increases in ¹³C% enrichment of [M+4]citrate and [M+5]citrate concentrations of [¹³C₃]propionate indicate propionate conversion to acetyl CoA and subsequent entry of acetyl CoA into the tricarboxylic acid cycle in dairy cows in the PP period. This research presents evidence that despite an increase in hepatic acetyl CoA concentration and general consensus on the upregulation of gluconeogenesis of dairy cows during the PP period, carbon derived from propionate contributes to the pool of acetyl CoA, which increases as concentration of propionate increases, in addition to stimulating oxidation of acetyl CoA from other sources. Because of the hypophagic effects of propionate, but importance of propionate as a glucose precursor, a balance of propionate supply to dairy cows could lead to improvements in dry matter intake, and subsequently, health and production in dairy cows.

Placental Metabolomics for Assessment of Sex-specific Differences in Fetal Development During Normal Gestation

The placenta is a metabolically active interfacial organ that plays crucial roles in fetal nutrient delivery, gas exchange and waste removal reflecting dynamic maternal and fetal interactions during gestation. There is growing evidence that the sex of the placenta influences fetal responses to external stimuli in utero, such as changes in maternal nutrition and exposure to environmental stressors. However, the exact biochemical mechanisms associated with sex-specific metabolic adaptations during pregnancy and its link to placental function and fetal development remain poorly understood. Herein, multisegment injection-capillary electrophoresis-mass spectrometry is used as a high throughput metabolomics platform to characterize lyophilized placental tissue (~2 mg dried weight) from C57BL/6J mice fed a standardized diet. Over 130 authentic metabolites were consistently measured from placental extracts when using a nontargeted metabolomics workflow with stringent quality control and robust batch correction. Our work revealed distinct metabolic phenotype differences that exist between male (n = 14) and female (n = 14) placentae collected at embryonic day E18.5. Intracellular metabolites associated with fatty acid oxidation and purine degradation were found to be elevated in females as compared to male placentae (p < 0.05, effect size >0.40), including uric acid, valerylcarnitine, hexanoylcarnitine, and 3-hydroxyhexanolycarnitine. This murine model sheds new insights into sex-specific differences in placental mitochondrial function and protective mechanisms against deleterious oxidative stress that may impact fetal growth and birth outcomes later in life.

The effect of uncouplers of oxidative phosphorylation on the feeding behavior of lactating dairy cows

Our objective was to determine the effects of uncouplers of oxidative phosphorylation on feeding behavior of lactating dairy cows. We hypothesized that uncouplers of oxidative phosphorylation would increase meal size and meal length and performed 2 experiments to test our hypothesis. In experiment 1, 4 late-lactation cows (345 ± 48.4 d in milk; mean ± SD) were administered a daily intrajugular injection of either 10 mg/kg of BW^0.75 of 2,4-dinitrophenol methyl ether (DNPME) and propylene carbonate or propylene carbonate (control; CON) in a crossover design with 2-d periods. In experiment 2, 8 early-lactation cows (11.3 ± 0.89 d in milk) were administered a daily intrajugular injection via jugular catheter of either 50 mg/kg of BW of sodium salicylate (SAL) and saline or saline (control; CON) in a crossover design with 1-d periods. Feeding behavior was recorded by a computerized data acquisition system and analyzed for the first 4 h after access to feed within 15 min of treatment for both experiments. Neither DNPME nor SAL affected meal size over the first 4 h after access to feed. However, DNPME increased meal length by 6.4 min (26.3 vs. 19.9 min) and tended to decrease the number of meals (2.55 vs. 2.78 meals/4 h) over the first 4 h after access to feed compared with CON. Both DNPME and SAL decreased eating rate over the first 4 h after access to feed compared with their respective controls (0.10 vs. 0.12 kg/min for DNPME vs. CON; 0.06 vs. 0.07 kg/min for SAL vs. CON). Lack of treatment effects on meal size may have been caused by increased rate of oxidation of fuels compensating for the disruption of oxidative phosphorylation.

Temporal effects of ruminal infusion of propionic acid on hepatic metabolism in cows in the postpartum period

A faster rate of infusion of propionic acid into the rumen of cows in the postpartum period increased meal size compared with a slower rate of infusion in a previous experiment. Because propionate is anaplerotic and stimulates oxidation of acetyl coenzyme A (CoA) in the liver, and hepatic oxidation has been linked to satiety, this result was opposite to our expected response. We then hypothesized that the faster rate of infusion might have saturated the pathway for propionate metabolism in hepatocytes resulting in lower first-pass extraction by the liver. Because we were measuring feeding behavior, we could not sample blood and liver tissue over time in that experiment. Therefore, to determine the temporal effects of propionic acid (PA) infusion on hepatic metabolism and plasma metabolites over the time course of a meal, we infused 1.25 mol of PA (2.5 L of 0.5M PA) over 5 min (FST) or 15 min (SLW) into the rumen. We evaluated response to PA infusions both before feeding, when ruminal PA production by rumen microbes is lower and hepatic acetyl CoA concentration is greater, and 4 h after feeding, when PA production is greater and hepatic acetyl CoA concentration is lower. Blood and liver samples were collected before, and after 5, 15, and 30 min of infusion. Contrary to our hypothesis, the rate of PA infusion into the rumen did not affect plasma propionate concentration, indicating the FST effects on feeding behavior were not because of a limitation on propionate uptake by the liver. However, FST increased plasma glucose and insulin concentrations faster than SLW, resulting in a reduction in plasma nonesterified fatty acid concentration during the time frame of meals. Decreased plasma nonesterified fatty acid concentration during infusion likely decreased the supply of acetyl CoA for oxidation in the liver. The FST treatment also increased fumarate concentration at 5 min after the initiation of infusion but did not affect oxaloacetate concentration compared with SLW, consistent with a limitation to propionate metabolism at that reaction. A metabolic bottleneck at the malate dehydrogenase reaction for FST compared with SLW would further contribute to a reduction in hepatic oxidation within the time frame of a meal, allowing greater meal size, consistent with the hepatic oxidation theory and our previous results.

Hepatic metabolism of propionate relative to meals for cows in the postpartum period

The objective of this research was to identify potential short-term metabolic bottlenecks of propionate metabolism in the liver of dairy cows in the postpartum (PP) period and how such bottlenecks are affected by feeding status. Propionate, produced primarily from the fermentation of starch, decreases dry matter intake for cows in the postpartum period, likely by stimulating oxidation of acetyl-CoA in the liver. In this study, 8 dairy cows [2 blocks of 4 cows each, 6.63 ± 1.19 (mean ± SD) days PP; body condition score of 2.84 ± 0.39] were administered a pulse dose of either 1.5 mol/500 mL of propionic acid (PA) or 500 mL of water (control; CON) to the rumen either 1 h before or 2 h after feeding in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Liver tissue was sampled at -1, 10 and 20 min relative to dosing, and blood was sampled at -30, -20, -10, -1, 5, 10, 15, 20, 25, 30, and 60 min relative to dosing. We hypothesized that rapid propionate absorption results in bottlenecks as enzymes become saturated and cofactors require regeneration. The PA treatment increased plasma propionate and insulin concentrations rapidly, with peaks reached by 5 min regardless of feeding status and cleared from the plasma within 30 min of dosing. The PA treatment decreased plasma nonesterified fatty acid concentration over 30 min compared with CON before but not after feeding. The PA treatment decreased plasma β-hydroxybutyrate concentration and increased plasma lactate concentration compared with CON both before and after feeding. The PA treatment also increased hepatic pyruvate and lactate concentrations compared with CON. The PA treatment tended to increase hepatic isocitrate and fumarate concentrations but did not affect hepatic malate and oxaloacetate concentrations, suggesting that elevated mitochondrial NADH/NAD⁺ may have slowed the isocitrate dehydrogenase and fumarase reactions. The PA treatment also increased succinate concentration compared with CON, suggesting that a bottleneck may be present at succinate dehydrogenase. The PA treatment tended to increase citrate concentration despite having no effects on acetyl-CoA or oxaloacetate concentrations. These results are in agreement with our hypothesis that rapid absorption of propionate from the rumen and extraction by the liver results in metabolic bottlenecks in the liver that may affect feeding behavior and dry matter intake in dairy cows in the PP period.

High-fat diet intake modulates maternal intestinal adaptations to pregnancy and results in placental hypoxia, as well as altered fetal gut barrier proteins and immune markers

KEY POINTS

Maternal obesity has been associated with shifts in intestinal microbiota, which may contribute to impaired barrier function Impaired barrier function may expose the placenta and fetus to pro-inflammatory mediators We investigated the impacts of diet-induced obesity in mice on maternal and fetal intestinal structure and placental vascularization Diet-induced obesity decreased maternal intestinal short chain fatty acids and their receptors, impaired gut barrier integrity and was associated with fetal intestinal inflammation. Placenta from obese mothers showed blood vessel immaturity, hypoxia, increased transcript levels of inflammation, autophagy and altered levels of endoplasmic reticulum stress markers. These data suggest that maternal intestinal changes probably contribute to adverse placental adaptations and also impart an increased risk of obesity in the offspring via alterations in fetal gut development.

ABSTRACT

Shifts in maternal intestinal microbiota have been implicated in metabolic adaptations to pregnancy. In the present study, we generated cohorts of female C57BL/6J mice fed a control (17% kcal fat, n = 10-14) or a high-fat diet (HFD 60% kcal from fat, n = 10-14; ad libitum) aiming to investigate the impact on the maternal gut microbiota, intestinal inflammation and gut barrier integrity, placental inflammation and fetal intestinal development at embryonic day 18.5. HFD was associated with decreased relative abundances of short-chain fatty acid (SCFA) producing genera during pregnancy. These diet-induced shifts paralleled decreased maternal intestinal mRNA levels of SCFA receptor Gpr41, modestly decreased cecal butyrate, and altered mRNA levels of inflammatory cytokines and immune cell markers in the maternal intestine. Maternal HFD resulted in impaired gut barrier integrity, with corresponding increases in circulating maternal levels of lipopolysaccharide (LPS) and tumour necrosis factor. Placentas from HFD dams demonstrated blood vessel immaturity and hypoxia; decreased free carnitine, acylcarnitine derivatives and trimethylamine-N-oxide; and altered mRNA levels of inflammation, autophagy, and ER stress markers. HFD exposed fetuses had increased activation of nuclear factor-kappa B and inhibition of the unfolded protein response in the developing intestine. Taken together, these data suggest that HFD intake prior to and during pregnancy shifts the composition of the maternal gut microbiota and impairs gut barrier integrity, resulting in increased maternal circulating LPS, which may ultimate contribute to changes in placental vascularization and fetal gut development.

Cochlear compound action potentials from high-level tone bursts originate from wide cochlear regions that are offset toward the most sensitive cochlear region

Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied the spatial origins of AN CAPs evoked by 2- to 16-kHz tone bursts at several sound levels by slowly injecting kainic acid solution into the cochlear apex of anesthetized guinea pigs. As the solution flowed from apex to base, it sequentially reduced CAP responses from low- to high-frequency cochlear regions. The times at which CAPs were reduced, combined with the cochlear location traversed by the solution at that time, showed the cochlear origin of the removed CAP component. For low-level tone bursts, the CAP origin along the cochlea was centered at the characteristic frequency (CF). As sound level increased, the CAP center shifted basally for low-frequency tone bursts but apically for high-frequency tone bursts. The apical shift was surprising because it is opposite the shift expected from AN tuning curve and basilar membrane motion asymmetries. For almost all high-level tone bursts, CAP spatial origins extended over 2 octaves along the cochlea. Surprisingly, CAPs evoked by high-level low-frequency (including 2 kHz) tone bursts showed little CAP contribution from CF regions ≤ 2 kHz. Our results can be mostly explained by spectral splatter from the tone-burst rise times, excitation in AN tuning-curve "tails," and asynchronous AN responses to high-level energy ≤ 2 kHz. This is the first time CAP origins have been identified by a spatially specific technique. Our results show the need for revising the interpretation of the cochlear origins of high-level CAPs-ABR wave 1. NEW & NOTEWORTHY Cochlear compound action potentials (CAPs) and auditory brain stem responses (ABRs) are routinely used in laboratories and clinics. They are typically interpreted as arising from the cochlear region tuned to the stimulus frequency. However, as sound level is increased, the cochlear origins of CAPs from tone bursts of all frequencies become very wide and their centers shift toward the most sensitive cochlear region. The standard interpretation of CAPs and ABRs from moderate to intense stimuli needs revision.

Inhibition of Clostridium perfringens growth by potassium lactate during an extended cooling of cooked uncured ground turkey breasts

The U.S. Department of Agriculture's Food Safety and Inspection Service compliance guideline known as Appendix B specifies chilling time and temperature limits for cured and uncured meat products to inhibit growth of spore-forming bacteria, particularly Clostridium perfringens. Sodium lactate and potassium lactate inhibit toxigenic growth of Clostridium botulinum, and inhibition of C. perfringens has been reported. In this study, a cocktail of spores of three C. perfringens strains (ATCC 13124, ATCC 12915, and ATCC 12916) were inoculated into 100-g samples of ground skinless, boneless turkey breast formulated to represent deli-style turkey breast. Three treatment groups were supplemented with 0 (control), 1, or 2% potassium lactate (pure basis), cooked to 71 °C, and assayed for C. perfringens growth during 10 or 12 h of linear cooling to 4 °C. In control samples, populations of C. perfringens increased 3.8 to 4.7 log CFU/g during the two chilling protocols. The 1% potassium lactate treatment supported only a 2.5- to 2.7-log increase, and the 2% potassium lactate treatment limited growth to a 0.56- to 0.70-log increase. When compared with the control, 2% potassium lactate retarded growth by 2.65 and 4.21 log CFU/g for the 10- and 12-h cooling protocols, respectively. These results confirm that the addition of 2% potassium lactate inhibits growth of C. perfringens and that potassium lactate can be used as an alternative to sodium nitrite for safe extended cooling of uncured meats.

β-Amyloid burden in healthy aging: regional distribution and cognitive consequences

OBJECTIVE

Several lines of evidence suggest that pathologic changes underlying Alzheimer disease (AD) begin years prior to the clinical expression of the disease, underscoring the need for studies of cognitively healthy adults to capture these early changes. The overall goal of the current study was to map the cortical distribution of β-amyloid (Aβ) in a healthy adult lifespan sample (aged 30-89), and to assess the relationship between elevated amyloid and cognitive performance across multiple domains.

METHODS

A total of 137 well-screened and cognitively normal adults underwent Aβ PET imaging with radiotracer (18)F-florbetapir. Aβ load was estimated from 8 cortical regions. Participants were genotyped for APOE and tested for processing speed, working memory, fluid reasoning, episodic memory, and verbal ability.

RESULTS

Aβ deposition is distributed differentially across the cortex and progresses at varying rates with age across cortical brain regions. A subset of cognitively normal adults aged 60 and over show markedly elevated deposition, and also had a higher rate of APOE ε4 (38%) than nonelevated adults (19%). Aβ burden was linked to poorer cognitive performance on measures of processing speed, working memory, and reasoning.

CONCLUSIONS

Even in a highly selected lifespan sample of adults, Aβ deposition is apparent in some adults and is influenced by APOE status. Greater amyloid burden was related to deleterious effects on cognition, suggesting that subtle cognitive changes accrue as amyloid progresses.

Differential aging of the medial temporal lobe: A study of a five-year change

OBJECTIVE

To test the hypothesis that entorhinal cortex (EC) volume decreases at a slower rate than the hippocampal (HC) volume in healthy adults, and to examine whether the rate of shrinkage increases with age.

METHODS

Volumes of the HC and EC were measured twice on MRI scans of 54 healthy adults (aged 26 to 82 years), with an average interval of 5 years.

RESULTS

Markedly different age trends were noted in the examined regions. The EC showed no age-related differences on both occasions and only minimal age-related change (0.33%/y). By contrast, the HC exhibited significant age-related differences at baseline and at follow-up evaluation and decreased at a faster pace of 0.86%/y. Older participants (aged > or = 50 years) showed increased annual shrinkage of the HC (1.18%) and EC shrinkage (0.53%/y). The rate of HC volume loss significantly exceeded that of the EC. No EC shrinkage and modest HC volume reduction were observed in people aged <50 years.

CONCLUSIONS

Age-related shrinkage occurs in the medial temporal lobes of healthy adults, with significant hippocampal decline and minimal entorhinal changes. In both regions, the rate of decline accelerates with age, although the role of pathologic factors in age-related increase of volume loss merits further investigation.

Synaptic vesicle recruitment for release explored by Monte Carlo simulation at the crayfish neuromuscular junction

Neurotransmission at chemically transmitting synapses requires calcium-mediated fusion of synaptic vesicles with the presynaptic membrane. Utilizing ultrastructural information available for the crustacean excitatory neuromuscular junction, we developed a model that employs the Monte Carlo simulation technique to follow the entry and movement of Ca2+ ions at a presynaptic active zone, where synaptic vesicles are preferentially docked for release. The model includes interaction of Ca2+ with an intracellular buffer, and variable separation between calcium channels and vesicle-associated Ca2+-binding targets that react with Ca2+ to trigger vesicle fusion. The end point for vesicle recruitment for release was binding of four Ca2+ ions to the target controlling release. The results of the modeling experiments showed that intracellular structures that interfere with Ca2+ diffusion (in particular synaptic vesicles) influence recruitment or priming of vesicles for release. Vesicular recruitment is strongly influenced by the separation distance between an opened calcium channel and the target controlling release, and by the concentration and binding properties of the intracellular buffers, as in previous models. When a single opened calcium channel is very close to the target, a single synaptic vesicle can be recruited. However, many of the single-channel openings actuated by a nerve impulse are likely to be ineffective for release, although they contribute to the buildup of total intracellular Ca2+. Thus, the overall effectiveness of single calcium channels in causing vesicles to undergo exocytosis is likely quite low.Key words: synapse, Monte Carlo simulation, synaptic vesicle, active zone, vesicle recruitment, crayfish, calcium, calcium buffer.

Lessons learned from three physician-equity models

To improve the profitability of group practice ownership, some healthcare organizations have structured arrangements to include a form of physician equity. An equity incentive is designed to encourage physician behavior that supports business operations by tying financial reward to overall organizational performance. Three physician-equity models--third-party integration, joint venture management services organization (MSO), and physician-owned practice management company--have used the physician equity incentive with varying degrees of success. The experiences of three healthcare systems that implemented these models demonstrates that strategies often cannot be executed as planned, growth should not be assumed, and the changing healthcare marketplace is unpredictable.

Synaptic vesicle recruitment for release explored by Monte Carlo stimulation at the crayfish neuromuscular junction

Neurotransmission at chemically transmitting synapses requires calcium-mediated fusion of synaptic vesicles with the presynaptic membrane. Utilizing ultrastructural information available for the crustacean excitatory neuromuscular junction, we developed a model that employs the Monte Carlo simulation technique to follow the entry and movement of Ca2+ ions at a presynaptic active zone, where synaptic vesicles are preferentially docked for release. The model includes interaction of Ca2+ with an intracellular buffer, and variable separation between calcium channels and vesicle-associated Ca(2+)-binding targets that react with Ca2+ to trigger vesicle fusion. The end point for vesicle recruitment for release was binding of four Ca2+ ions to the target controlling release. The results of the modeling experiments showed that intracellular structures that interfere with Ca2+ diffusion (in particular synaptic vesicles) influence recruitment or priming of vesicles for release. Vesicular recruitment is strongly influenced by the separation distance between an opened calcium channel and the target controlling release, and by the concentration and binding properties of the intracellular buffers, as in previous models. When a single opened calcium channel is very close to the target, a single synaptic vesicle can be recruited. However, many of the single-channel openings actuated by a nerve impulse are likely to be ineffective for release, although they contribute to the buildup of total intracellular Ca2+. Thus, the overall effectiveness of single calcium channels in causing vesicles to undergo exocytosis is likely quite low.

Alternatives to traditional capitation in managed care agreements

Risk arrangements typically fall into one of three categories: primary care capitation, professional services capitation, and global, or full-risk, capitation. Yet, in light of various disadvantages associated with these three methods, such as high administrative costs and inappropriate levels of risk assumed by providers, many healthcare payers and providers are experimenting with alternative payment plans. These alternatives include contact capitation arrangements, under which specialists receive a capitation payment on a per referral basis; open-access arrangements, under which patients do not need a gatekeeper referral to see specialists; and capitation arrangements with quality and hospital utilization bonuses, under which specialists and primary care physicians receive a capitation payment plus the potential for bonuses based on quality and utilization criteria.

Physician equity in health care delivery systems: three alternative models

The 1990s have seen many health care organizations attempting to merge, acquire, or affiliate with physician groups. Many have failed to provide physicians a stake in the success of the newly formed enterprise, frequently resulting in declining physician productivity, poor morale, and large operating losses. These problems warrant a reexamination of the traditional acquisition model of growth in favor of structures that retain a physician ownership component. This article examines three models of health care organization in which physicians share in the success of the enterprise and compares them in terms of ownership structure, governance, and funds flow.

Matching physician compensation plans to capitation levels

As managed care penetration increases, physician compensation plans need to reflect the current transition from fee-for-service to capitated payment. In choosing the compensation structure that will be most beneficial to the success of the group practice and secure physician buy-in, practices need to assess their mission, goals, and corporate culture. They also need to assess their percentage of capitation to total revenues and develop, when necessary, new compensation pools that reward physicians for a variety of behaviors, such as increased productivity and utilization control. Compensation plans should be fair, flexible, and simple to understand and administer.

Evaluating and negotiating a profitable capitation contract

Evaluating the financial terms of capitation contracts and negotiating their nonfinancial provisions are becoming increasingly important responsibilities for healthcare financial managers. To evaluate the financial terms of a contract, financial managers must understand both incremental and replacement pricing strategies. They also must understand when strategic positioning objectives make a capitated plan attractive despite limited financial rewards. Before a contract is accepted, financial managers can take steps to increase its potential profitability by negotiating the nonfinancial provisions that can help control contract expenses. These provisions are related to services to be provided, payment terms, withholds and risk pools, access to data, provision of eligibility data, utilization review and quality assurance procedures, filing of grievances, contract renewal terms, and contract termination.

A "high-tech," "soft-touch" immunization program for members of a Medicaid managed care organization

Immunization rates among the very poor are critically low. The solution to improving rates requires technological tracking of immunizations linked to extensive home visiting outreach services as well as physician and member support services to increase compliance with recommended immunization schedules. This paper describes the development and implementation of a comprehensive immunization program which incorporates these strategies for members of a Medicaid managed care organization. Analysis of preliminary data provides some indication of the value of the tracking system and the effectiveness of incentives and home visiting on member compliance with immunizations.

Corticotropin-releasing factor binding protein dimerizes after association with ligand

We have suggested recently that the fall in plasma CRF-binding protein (BP) during the last few weeks of pregnancy is a direct effect of association with its ligand because of the rapid decrease in plasma BP concentration seen in normal males reaching a nadir some 15 min after a bolus injection of synthetic CRF. In the present study, we have investigated the physicochemical properties of both natural and recombinant BP by gel filtration under physiological conditions and have shown that association of human CRF to this BP results in an increase in molecular weight consistent with the formation of a dimer form of the BP ligand complex. The dimer is more stable when the interaction occurs in the presence of serum or if a peptide with a higher affinity for the BP is substituted as ligand. Experimental evidence would also suggest that the dimer BP has a higher affinity for ligand than the monomeric form. We suggest that this dimerization occurs in vivo when CRF is released into the bloodstream and provides the trigger that causes the uptake of the complex at specific receptor sites.

Auditory brainstem response to tone bursts in quiet, notch noise, highpass noise, and broadband noise

This study investigated the effects of tone bursts (1000 Hz, 2000 Hz, and 4000 Hz) in quiet, notch noise, highpass noise, and broadband noise on the identifiability, latency, and amplitude of the auditory brainstem response (wave V). Normal listeners were presented with 40 dB and 80 dB nHL tone bursts having rise-plateau-fall times of 1 msec. Wave V was observed in all subjects at 40 dB and 80 dB nHL for the quiet and noise conditions. The latency findings suggest that responses elicited by the 80 dB nHL tone bursts in quiet were, in part, mediated by regions on the basilar membrane that did not correspond to the center frequency of the tone burst. To increase frequency-specificity, high-level tone bursts (e.g., 80 dB nHL) should be mixed with notch, highpass, or broadband noise. The use of noise conditions for low intensity levels (e.g., 40 dB nHL) does not appear necessary for isolating the response because both the notch and the highpass conditions yielded latencies similar to the quiet condition. Although similar wave V amplitudes were found at all frequencies, amplitudes were smaller for the broadband noise than for the quiet, notch, and highpass conditions. Thus, the latter conditions seem preferred.