Human quad liver-on-chip system as a tool toward bridging the gap between animals and humans regarding toxicology and pharmacology of a cannabidiol-rich cannabis extract.

Cannabidiol (CBD) is a major phytocannabinoid from Cannabis sativa. It is currently widely available and widely used in the USA, but despite its rapid progress to market, the pharmacology and toxicology of both CBD and cannabidiol-rich cannabis extracts (CRCE) remain largely unknown. The goals of this study were to investigate the potential of a novel human microphysiological system to emulate CRCE-induced hepatotoxicity and pharmacological properties demonstrated in animal models. For this purpose, C57BL6/J male mice were subjected to dosing with either 0, 61.5, 184.5, or 615 mg/kg of CRCE for 10 days. The liver-on-chip system, incorporating human primary hepatocytes, sinusoidal endothelial cells, as well as Kupffer and stellate cells was subjected to 0, 300, 1,200, or 4,400 ng/mL of CRCE (8 h exposure followed by 16 h washout) for 5 days. Administration of CRCE in mice resulted in nearly 4-fold elevations of plasma ALT at 615 mg/kg (p < 0.01) and a dose-dependent decrease in intrahepatic miR-122. Elevated levels of ALT, paralleled by decreased intrahepatic and increased effluent levels of miR-122, were also observed in the liver-on-chip, although these results were not statistically significant. Exposure to CRCE resulted in a robust and dose-dependent induction of key cytochrome P450 enzymes, namely Cyp1a2, Cyp2b6 (CYP2B10), Cyp2e1, and Cyp2c9 (CYP2C19) in both mouse livers and liver-on-chip. The results of this study demonstrate the congruence between the responses observed in mouse and human liver-on-chip experimental systems and provide evidence of the potential microphysiological systems hold for translating animal data into clinical practice.

Associations Between Maternal Physical Activity, Maternal Lipid Levels, and Infant Anthropometric Outcomes at Two Weeks of Age.

BACKGROUND: This study determined the relationship between physical activity (PA), circulating lipids throughout pregnancy and infant anthropometric outcomes at birth and 2 weeks of age. METHODS: Women (N = 234) with normal weight (NW, BMI 18.5-24.9 kg/m2) and with overweight and class I obesity (OW/OB, BMI 25-35 kg/m2) were categorized into high and low PA based on average cohort steps during pregnancy (8099 steps/day). Circulating fasting lipids were measured at each trimester. Standardized methods were used to obtain anthropometrics measures. Infant body composition was estimated by quantitative nuclear magnetic resonance (EchoMRI-AH small; ECHO Medical Systems). RESULTS: Women with NW who had higher activity had lower circulating triglycerides (TG) and total cholesterol (TC) levels at 12 weeks compared to women with NW and low activity (p < 0.05). Women with OW/OB and high activity level throughout pregnancy had lower circulating TG, and low density lipoprotein (LDL), at 12 weeks, lower LDL at 24 weeks, and lower TG at 36 weeks compared to the women with OW/OB who had low activity levels (p < 0.05). For children born to women with OW/OB, maternal circulating TG and LDL were most associated with infant anthropometrics at 2 weeks of age. CONCLUSION: This study supports that higher PA during pregnancy is associated with lower lipid levels throughout pregnancy with a greater effect size in women with OW/OB. Maternal lipids were associated with anthropometrics and infant body composition at two weeks of life in women with OW/OB.

Metabolic physiology and skeletal muscle phenotypes in male and female myoglobin knockout mice.

Myoglobin (Mb) is a regulator of O2 bioavailability in type I muscle and heart, at least when tissue O2 levels drop. Mb also plays a role in regulating cellular nitric oxide (NO) pools. Robust binding of long-chain fatty acids and long-chain acylcarnitines to Mb, and enhanced glucose metabolism in hearts of Mb knockout (KO) mice, suggest additional roles in muscle intermediary metabolism and fuel selection. To evaluate this hypothesis, we measured energy expenditure (EE), respiratory exchange ratio (RER), body weight gain and adiposity, glucose tolerance, and insulin sensitivity in Mb knockout (Mb-/-) and wild-type (WT) mice challenged with a high-fat diet (HFD, 45% of calories). In males (n = 10/genotype) and females (n = 9/genotype) tested at 5-6, 11-12, and 17-18 wk, there were no genotype effects on RER, EE, or food intake. RER and EE during cold (10°C, 72 h), and glucose and insulin tolerance, were not different compared with within-sex WT controls. At ∼18 and ∼19 wk of age, female Mb-/- adiposity was ∼42%-48% higher versus WT females (P = 0.1). Transcriptomics analyses (whole gastrocnemius, soleus) revealed few consistent changes, with the notable exception of a 20% drop in soleus transferrin receptor (Tfrc) mRNA. Capillarity indices were significantly increased in Mb-/-, specifically in Mb-rich soleus and deep gastrocnemius. The results indicate that Mb loss does not have a major impact on whole body glucose homeostasis, EE, RER, or response to a cold challenge in mice. However, the greater adiposity in female Mb-/- mice indicates a sex-specific effect of Mb KO on fat storage and feed efficiency.NEW & NOTEWORTHY The roles of myoglobin remain to be elaborated. We address sexual dimorphism in terms of outcomes in response to the loss of myoglobin in knockout mice and perform, for the first time, a series of comprehensive metabolic studies under conditions in which fat is mobilized (high-fat diet, cold). The results highlight that myoglobin is not necessary and sufficient for maintaining oxidative metabolism and point to alternative roles for this protein in muscle and heart.

Early infant feeding effect on growth and body composition during the first 6 years and neurodevelopment at age 72 months.

BACKGROUND: This study longitudinally characterized the developmental status, growth, and body composition of children who were fed human milk (breastfed, BF), cow's milk-based (MF), or soy protein-based (SF) infant formula from 3 to 12 months. METHODS: Standardized anthropometrics and dual-energy X-ray absorptiometry were used to characterize growth and body composition at 3, 6, 9, 12, 24, 36, 48, 60, and 72 months (NCT00616395). Preschool Language Scale-3, Children's Memory Scale Index (CMS), and Wechsler Preschool and Primary Scale of Intelligence were administered at age 72 months. Mixed-effects models adjusting for gestational age, birth weight, child race and sex, parental education, and maternal IQ were performed. RESULTS: Body Mass index (BMI) was significantly lower between 24 and 72 months in BF children compared to SF children. At 3 and 6 months, BF infants had significantly higher fat mass (FM) than SF infants, whereas BF children had significantly lower FM at 36 and 48 months than SF children. Delayed Recognition Index of the CMS was higher for SF than for MF participants (p = 0.009). There was no other significant difference in developmental outcomes between groups. CONCLUSIONS: In conclusion, BF, MF, and SF support adequate growth and development up to age 6 years. IMPACT: Although soy protein-based infant formula is reported to support normal infant growth and development compared to cow's milk-based formula and human milk, there are limited data on the effect of these feeding methods in school-aged children. This study suggests a significant difference in body composition, specifically BMI, after 24 months between infant feeding methods during the first year of life and in early childhood; however, all diets provide adequate nutrients to maintain normal development up to 72 months.

Impact of Student-Run Free Clinics in Urgent Care.

As Emergency Departments (EDs) become increasingly crowded, the non-urgent use of EDs exacerbates this problem. Uninsured patients have the highest percentage of non-urgent ED visits and free healthcare clinics provide access to care for the uninsured. This study analyzed the patient population of the 12th Street Health and Wellness Center (HWC), a student-run free clinic (SRFC), to understand the impact of SRFCs in urgent care. 2024 return and new patient intake forms from the HWC were analyzed. Multivariable logistic regression was performed to see which factors from the patient intake forms increase the probability that a patient came will into the clinic for urgent care. About 10% of the HWC patient population uses the clinic for emergencies, of which, 94% of them were not referred to the ED. If the HWC was not available, most of these uninsured individuals would have gone to an ED and incurred an estimated total cost of $39,515.80 in 2019. Multivariable logistic regression indicated that patients that came via walk-in are significantly more likely to seek urgent care at the clinic. Further, patients without insurance and patients who need a Spanish interpreter have a higher tendency to seek urgent care at this clinic. SRFCs save their surrounding EDs thousands of dollars in non-urgent ED visits. SRFCs should be attentive to patients who come in without an appointment, without insurance, and who need a Spanish interpreter because they are more likely to come in for an emergency.

Coupling of energy intake and energy expenditure across a temperature spectrum: impact of diet-induced obesity in mice.

Obesity and its metabolic sequelae are implicated in dysfunction of the somatosensory, sympathetic, and hypothalamic systems. Because these systems contribute to integrative regulation of energy expenditure (EE) and energy intake (EI) in response to ambient temperature (Ta) changes, we hypothesized that diet-induced obesity (DIO) disrupts Ta-associated EE-EI coupling. C57BL/6N male mice were fed a high-fat diet (HFD; 45% kcal) or low-fat diet (LFD; 10% kcal) for ∼9.5 wk; HFD mice were then split into body weight (BWT) quartiles (n = 8 each) to study DIO-low gainers (Q1) versus -high gainers (Q4). EI and indirect calorimetry (IC) were measured over 3 days each at 10°C, 20°C, and 30°C. Responses did not differ between LFD, Q1, and Q4; EI and BWT-adjusted EE increased rapidly when transitioning toward 20°C and 10°C. In all groups, EI at 30°C was not reduced despite lower EE, resulting in positive energy balance and respiratory exchange ratios consistent with increased de novo lipogenesis, energy storage, and relative hyperphagia. We conclude that 1) systems controlling Ta-dependent acute EI/EE coupling remained intact in obese mice and 2) rapid coupling of EI/EE at cooler temperatures is an important adaptation to maintain energy stores and defend body temperature, but less critical at thermoneutrality. A post hoc analysis using digestible EI plus IC-calculated EE suggests that standard IC assumptions for EE calculation require further validation in the setting of DIO. The experimental paradigm provides a platform to query the hypothalamic, somatosensory, and sympathetic mechanisms that drive Ta-associated EI/EE coupling.

Paradoxical Patterns of Sinusoidal Obstruction Syndrome-Like Liver Injury in Aged Female CD-1 Mice Triggered by Cannabidiol-Rich Cannabis Extract and Acetaminophen Co-Administration.

The goal of this study was to investigate the potential for a cannabidiol-rich cannabis extract (CRCE) to interact with the most common over-the-counter drug and the major known cause of drug-induced liver injury-acetaminophen (APAP)-in aged female CD-1 mice. Gavaging mice with 116 mg/kg of cannabidiol (CBD) [mouse equivalent dose (MED) of 10 mg/kg of CBD] in CRCE delivered with sesame oil for three consecutive days followed by intraperitoneally (i.p.) acetaminophen (APAP) administration (400 mg/kg) on day 4 resulted in overt toxicity with 37.5% mortality. No mortality was observed in mice treated with 290 mg/kg of CBD+APAP (MED of 25 mg/kg of CBD) or APAP alone. Following CRCE/APAP co-administration, microscopic examination revealed a sinusoidal obstruction syndrome-like liver injury-the severity of which correlated with the degree of alterations in physiological and clinical biochemistry end points. Mechanistically, glutathione depletion and oxidative stress were observed between the APAP-only and co-administration groups, but co-administration resulted in much greater activation of c-Jun N-terminal kinase (JNK). Strikingly, these effects were not observed in mice gavaged with 290 mg/kg CBD in CRCE followed by APAP administration. These findings highlight the potential for CBD/drug interactions, and reveal an interesting paradoxical effect of CBD/APAP-induced hepatotoxicity.

A One-Year Institutional View of Resident Physician Burnout.

OBJECTIVES: This prospective study explores the prevalence, associated characteristics, and trajectory of burnout over one academic year in a multidisciplinary sample of resident physicians using a relatively new burnout survey instrument. METHODS: All residents from a U.S. academic health center (n = 633) were invited to complete the Copenhagen Burnout Inventory (CBI) three times, with 4-month time lags between invitations. A total of 281 (44%) provided complete CBI survey responses at least once, and 43 (7%) did at all three times. Descriptive statistics, cross-sectional analyses, correlations, and multivariable linear regression analyses were computed, as well as repeated measures ANOVAs and paired t tests, as appropriate, for each CBI domain (personal, work, patient-related burnout). RESULTS: About half had CBI scores indicating moderate-to-high levels of personal burnout (49-52%) and work-related burnout (45-49%), whereas patient-related burnout was less common (14-24%). However, patient-related burnout increased significantly from the beginning to the end of the year. Regression analyses indicated patient-related burnout was significantly higher for postgraduate year 1-2 residents compared to PGY 4+ residents, but was not significantly different by gender. Personal and work burnout scores were significantly higher for females. Persistently high burnout was observed in only 6% of respondents. CONCLUSIONS: In this study of resident physicians using the CBI, burnout was prevalent and higher levels of burnout were observed for females on the personal and work burnout domains, while junior residents had higher patient-related burnout. Persistently, high burnout was rare. The CBI demonstrated high reliability, was practical to administer, and produced similar results with existing burnout research.

Elevated Diastolic Closing Margin Is Associated with Intraventricular Hemorrhage in Premature Infants.

OBJECTIVE: To determine whether the diastolic closing margin (DCM), defined as diastolic blood pressure minus critical closing pressure, is associated with the development of early severe intraventricular hemorrhage (IVH). STUDY DESIGN: A reanalysis of prospectively collected data was conducted. Premature infants (gestational age 23-31 weeks) receiving mechanical ventilation (n = 185) had ∼1-hour continuous recordings of umbilical arterial blood pressure, middle cerebral artery cerebral blood flow velocity, and PaCO2 during the first week of life. Models using multivariate generalized linear regression and purposeful selection were used to determine associations with severe IVH. RESULTS: Severe IVH (grades 3-4) was observed in 14.6% of the infants. Irrespective of the model used, Apgar score at 5 minutes and DCM were significantly associated with severe IVH. A clinically relevant 5-mm Hg increase in DCM was associated with a 1.83- to 1.89-fold increased odds of developing severe IVH. CONCLUSION: Elevated DCM was associated with severe IVH, consistent with previous animal data showing that IVH is associated with hyperperfusion. Measurement of DCM may be more useful than blood pressure in defining cerebral perfusion in premature infants.

The Diastolic Closing Margin Is Associated with Intraventricular Hemorrhage in Premature Infants.

Premature infants are at an increased risk of intraventricular hemorrhage (IVH). The roles of hypotension and hyperemia are still debated. Critical closing pressure (CrCP) is the arterial blood pressure (ABP) at which cerebral blood flow (CBF) ceases. When diastolic ABP is equal to CrCP, CBF occurs only during systole. The difference between diastolic ABP and CrCP is the diastolic closing margin (DCM). We hypothesized that a low DCM was associated with IVH. One hundred eighty-six premature infants, with a gestational age (GA) range of 23-33 weeks, were monitored with umbilical artery catheters and transcranial Doppler insonation of middle cerebral artery flow velocity for 1-h sessions over the first week of life. CrCP was calculated linearly and using an impedance model. A multivariate generalized linear regression model was used to determine associations with severe IVH (grades 3-4). An elevated DCM by either method was associated with IVH (p < 0.0001 for the linear method; p < 0.001 for the impedance model). Lower 5-min Apgar scores, elevated mean CBF velocity, and lower mean ABP were also associated with IVH (p < 0.0001). Elevated DCM, not low DCM, was associated with severe IVH in this cohort.

Treatment with a monoclonal antibody against methamphetamine and amphetamine reduces maternal and fetal rat brain concentrations in late pregnancy.

We hypothesized that treatment of pregnant rat dams with a dual reactive monoclonal antibody (mAb4G9) against (+)-methamphetamine [METH; equilibrium dissociation rate constant (KD) = 16 nM] and (+)-amphetamine (AMP; KD = 102 nM) could confer maternal and fetal protection from brain accumulation of both drugs of abuse. To test this hypothesis, pregnant Sprague-Dawley rats (on gestational day 21) received a 1 mg/kg i.v. METH dose, followed 30 minutes later by vehicle or mAb4G9 treatment. The mAb4G9 dose was 0.56 mole-equivalent in binding sites to the METH body burden. Pharmacokinetic analysis showed baseline METH and AMP elimination half-lives were congruent in dams and fetuses, but the METH volume of distribution in dams was nearly double the fetal values. The METH and AMP area under the serum concentration-versus-time curves from 40 minutes to 5 hours after mAb4G9 treatment increased >7000% and 2000%, respectively, in dams. Fetal METH serum did not change, but AMP decreased 23%. The increased METH and AMP concentrations in maternal serum resulted from significant increases in mAb4G9 binding. Protein binding changed from ∼15% to > 90% for METH and AMP. Fetal serum protein binding appeared to gradually increase, but the absolute fraction bound was trivial compared with the dams. mAb4G9 treatment significantly reduced METH and AMP brain values by 66% and 45% in dams and 44% and 46% in fetuses (P < 0.05), respectively. These results show anti-METH/AMP mAb4G9 therapy in dams can offer maternal and fetal brain protection from the potentially harmful effects of METH and AMP.

Clinical efficacy of sertraline alone and augmented with gabapentin in recently abstinent cocaine-dependent patients with depressive symptoms.

BACKGROUND: Cocaine dependence is a major public health problem with no available robustly effective pharmacotherapy. This study's aim was to determine if treatment with sertraline (SERT) or SERT plus gabapentin (GBP) improved treatment retention, depressive symptoms, and/or cocaine use. METHODS: Depressed cocaine-dependent patients (N = 99) were enrolled in a 12-week, double-blind, randomized, placebo (PLA)-controlled, clinical trial and placed in research beds at a residential treatment facility (Recovery Centers of Arkansas). They were randomized by depressive symptom severity and inducted onto 1 of the following while residing at the Recovery Centers of Arkansas: SERT (200 mg/d), SERT (200 mg/d) plus GBP (1200 mg/d), or PLA. Participants transferred to outpatient treatment at the start of their third week, continued receiving study medications or PLA (weeks 3-12), and participated in weekly individual cognitive behavioral therapy. Compliance was facilitated through the use of contingency management procedures. Supervised urine samples were obtained thrice weekly and self-reported mood weekly. At the end of 12 weeks, participants were tapered off the study medication over 5 days and referred to a local treatment program. RESULTS: Sertraline, but not SERT plus GBP, showed a significantly lower overall percentage of cocaine-positive urine samples compared with that of PLA. A significantly greater percentage of participants experienced relapse in the PLA group (88.9%) compared with that of the SERT group (65.2%). Hamilton depression ratings decreased significantly over time regardless of the treatment group. Retention in treatment did not differ significantly between the treatment groups. CONCLUSIONS: Sertraline plus GBP may not be superior to SERT alone in delaying relapse among abstinent cocaine-dependent individuals undergoing cognitive behavioral therapy.

The effects of massage therapy to induce sleep in infants born preterm.

PURPOSE: The aim of this study was to determine whether massage therapy can be used as an adjunct intervention to induce sleep in infants born preterm. METHODS: Thirty infants born at a minimum of 28 weeks gestational age, who were at the time of the study between 32 and 48 weeks adjusted gestational age, were randomly assigned to receive massage therapy on 1 day and not receive massage on an alternate day. The Motionlogger Micro Sleep Watch Actigraph recorded lower extremity activity on the morning of each day. RESULTS: No significant difference was found between groups for sleep efficiency (P = .13) during the time period evaluated. Groups differed significantly during the time period after the massage ended with more infants sleeping on the nonmassage day (χ = 4.9802, P = .026). CONCLUSIONS: Massage is well tolerated in infants born preterm and infants do not fall asleep faster after massage than without massage.

Inter-strain variability in responses to a single administration of the cannabidiol-rich cannabis extract in mice.

Cannabidiol (CBD) has gained widespread popularity; however, its pharmacological and toxicological profiles in the context of human genetic diversity remain largely unexplored. Here, we investigated the variability in metabolism and toxicity of CBD-rich cannabis extract (CRCE) in genetically diverse mouse models: C57BL/6J, B6C3F1/J, and NZO/HlLtJ strains. Mice received a single dose of CRCE containing 57.9% CBD at dosages of 0, 246, 738, and 2460 mg/kg of CBD. At 24 h after treatment, no appreciable histomorphological changes were detected in the liver. Plasma bilirubin levels increased markedly in all strains at the highest CBD dose. Mice in all treatment groups displayed significant but distinct increases in ALT and AST levels. While B6C3F1/J and NZO/HlLtJ mice had negligible plasma CBD levels at 738 mg/kg, C57BL/6J mice exhibited levels exceeding 7000 ng/mL. At 2460 mg/kg, high CBD concentrations were found in B6C3F1/J and C57BL/6J mice, but markedly lower levels were seen in NZO/HlLtJ mice. Gene expression profiling showed significant increases in Cyp2b10 across all strains but varying responses in Cyp1a1 expression, indicating strain-specific CYP dysregulation. Genetically diverse mice exhibited differential pharmacological and toxicological responses to CRCE, suggesting a high potential for inter-individual variability in the pharmacology and toxicology of CBD in humans.

Effects of leptin on pedunculopontine nucleus (PPN) neurons.

Leptin, a hormone that regulates appetite and energy expenditure, is increased in obese individuals, although these individuals often exhibit leptin resistance. Obesity is characterized by sleep/wake disturbances, such as excessive daytime sleepiness, increased REM sleep, increased nighttime arousals, and decreased percentage of total sleep time. Several studies have shown that short sleep duration is highly correlated with decreased leptin levels in both animal and human models. Arousal and rapid eye movement (REM) sleep are regulated by the cholinergic arm of the reticular activating system, the pedunculopontine nucleus (PPN). The goal of this project was to determine the role of leptin in the PPN, and thus in obesity-related sleep disorders. Whole-cell patch-clamp recordings were conducted on PPN neurons in 9- to 17-day-old rat brainstem slices. Leptin decreased action potential (AP) amplitude, AP frequency, and h-current (I(H)). These findings suggest that leptin causes a blockade of Na⁺ channels. Therefore, we conducted an experiment to test the effects of leptin on Na⁺ conductance. To determine the average voltage dependence of this conductance, results from each cell were equally weighted by expressing conductance as a fraction of the maximum conductance in each cell. I Na amplitude was decreased in a dose-dependent manner, suggesting a direct effect of leptin on these channels. The average decrease in Na⁺ conductance by leptin was ~40 %. We hypothesize that leptin normally decreases activity in the PPN by reducing I(H) and I(Na) currents, and that in states of leptin dysregulation (i.e., leptin resistance) this effect may be blunted, therefore causing increased arousal and REM sleep drive, and ultimately leading to sleep-related disorders.

A longitudinal observational study of skeletal development between ages 3 mo and 6 y in children fed human milk, milk formula, or soy formula.

BACKGROUND: Early infant feeding can affect skeletal development. Most children are fed with breast milk, dairy-based infant formula, or soy-based infant formula during the first year of life. The National Health and Nutrition Examination Survey 2003-2010 reports that 12% of the US infants consume soy-based infant formula. Despite potential effects of soy-associated isoflavones on skeletal development, studies investigating bone metabolism and structural and functional bone indices in children are lacking. OBJECTIVE: The aim of this observational study was to investigate early effects of soy-based infant formula (SF group) intake on bone metabolism and structure during the first 6 y of life comparing with those of infants fed with breast milk (BF group) and dairy-based infant formula (MF group). METHODS: A total of 433 healthy infants were followed up from 3 mo to 6 y of age. Children's skeletal development was assessed using dual-energy X-ray absorptiometry (DXA; N = 433) and peripheral quantitative computed tomography (pQCT; n = 78). The urinary biomarkers of bone metabolism (N-terminal telopeptide of type I collagen [NTx] and osteocalcin) were evaluated using immunoassays at 6, 24, 60, and 72 mo. RESULTS: No statistically significant group differences were observed in bone mineral density (BMD) between the BF, MF, and SF groups, assessed using DXA or pQCT. At 6 y of age, children in the SF group showed significantly greater whole-body bone mineral content measured using DXA than those in the MF group. Six-month-old boys in the SF group demonstrated significantly greater levels of NTx than those in the MF group and significantly greater osteocalcin levels than those in the BF group. CONCLUSIONS: Together, these data suggest that although infants at age 6 mo in the SF group showed some enhanced bone metabolism compared with those in the BF and MF groups, as indicated by the urinary biomarkers, no differences in bone metabolism or BMD were noted between ages 2 and 6 y. This trial was registered at clinicaltrials.gov as NCT00616395.

Gamma band activity in the developing parafascicular nucleus.

The parafascicular nucleus (Pf) receives cholinergic input from the pedunculopontine nucleus, part of the reticular activating system involved in waking and rapid eye movement (REM) sleep, and sends projections to the cortex. We tested the hypothesis that Pf neurons fire maximally at gamma band frequency (30-90 Hz), that this mechanism involves high-threshold voltage-dependent P/Q- and N-type calcium channels, and that this activity is enhanced by the cholinergic agonist carbachol (CAR). Patch-clamped 9- to 25-day-old rat Pf neurons (n = 299) manifested a firing frequency plateau at gamma band when maximally activated (31.5 ± 1.5 Hz) and showed gamma oscillations when voltage-clamped at holding potentials above -20 mV, and the frequency of the oscillations increased significantly with age (24.6 ± 3.8 vs. 51.6 ± 4.4 Hz, P < 0.001) but plateaued at gamma frequencies. Cells exposed to CAR showed significantly higher frequencies early in development compared with those without CAR (24.6 ± 3.8 vs. 41.7 ± 4.3 Hz, P < 0.001) but plateaued with age. The P/Q-type calcium channel blocker ω-agatoxin-IVA (ω-Aga) blocked gamma oscillations, whereas the N-type blocker ω-conotoxin-GVIA (ω-CgTx) only partially decreased the power spectrum amplitude of gamma oscillations. The blocking effect of ω-Aga on P/Q-type currents and ω-CgTx on N-type currents was consistent over age. We conclude that P/Q- and N-type calcium channels appear to mediate Pf gamma oscillations during development. We hypothesize that the cholinergic input to the Pf could activate these cells to oscillate at gamma frequency, and perhaps relay these rhythms to cortical areas, thus providing a stable high-frequency state for "nonspecific" thalamocortical processing.

Effect of Obesity on Arithmetic Processing in Preteens With High and Low Math Skills: An Event-Related Potentials Study.

Preadolescence is an important period for the consolidation of certain arithmetic facts, and the development of problem-solving strategies. Obese subjects seem to have poorer academic performance in math than their normal-weight peers, suggesting a negative effect of obesity on math skills in critical developmental periods. To test this hypothesis, event-related potentials (ERPs) were collected during a delayed-verification math task using simple addition and subtraction problems in obese [above 95th body mass index (BMI) percentile] and non-obese (between 5th and 90th BMI percentile) preteens with different levels of math skill; thirty-one with low math skills (14 obese, mean BMI = 26.40, 9.79 years old; 17 non-obese, BMI = 17.45, 9.76 years old) and thirty-one with high math skills (15 obese, BMI = 26.90, 9.60 years old; 16 non-obese, BMI = 17.13, 9.63 years old). No significant differences between weight groups were observed in task accuracy regardless of their mathematical skill level. For ERPs, electrophysiological differences were found only in the subtraction condition; participants with obesity showed an electrophysiologic pattern associated with a reduced ability to allocate attention resources regardless of their math skill level, these differences were characterized by longer P300 latency than their normal-weight peers. Moreover, the participants with obesity with high math skills displayed hypoactivity in left superior parietal lobule compared with their normal-weight peers. Additionally, obese preteens with low math skills displayed smaller arithmetic N400 amplitude than non-obese participants, reflecting difficulties in retrieving visual, semantic, and lexical information about numbers. We conclude that participants with obesity are less able than their normal-weight peers to deploy their attention regardless of their behavioral performance, which seems to have a greater effect on obese participants with low math skills because they also show problems in the retrieval of solutions from working memory, resulting in a delay in the development of mathematical skills.

Proteomics Indicates Lactate Dehydrogenase Is Prognostic in Acetaminophen-Induced Acute Liver Failure Patients and Reveals Altered Signaling Pathways.

Better biomarkers to predict death early in acute liver failure (ALF) are needed. To that end, we obtained early (study day 1) and later (day 3) serum samples from transplant-free survivors (n = 28) and nonsurvivors (n = 30) of acetaminophen-induced ALF from the NIH-sponsored Acute Liver Failure Study Group and from control volunteers (n = 10). To identify proteins that increase early in serum during ALF, we selected individuals from this cohort for whom alanine aminotransferase was lower on day 1 than day 3, indicating a time point before peak injury (n = 10/group). We then performed untargeted proteomics on their day 1 samples. Out of 1682 quantifiable proteins, 361 were ≥ 4-fold elevated or decreased in ALF patients versus controls and 16 of those were further elevated or decreased ≥ 4-fold in nonsurvivors versus survivors, indicating potential to predict death. Interestingly, 1 of the biomarkers was lactate dehydrogenase (LDH), which is already measured in most clinical laboratories. To validate our proteomics results and to confirm the prognostic potential of LDH, we measured LDH activity in all day 1 and 3 samples from all 58 ALF patients. LDH was elevated in the nonsurvivors versus survivors on both days. In addition, it had prognostic value similar to the model for end-stage liver disease and outperformed the King's College Criteria, while a combination of model for end-stage liver disease and LDH together outperformed either alone. Finally, bioinformatics analysis of our proteomics data revealed alteration of numerous signaling pathways that may be important in liver regeneration. Overall, we conclude LDH can predict death in APAP-induced ALF.