Metabolic pathways of glucose and fructose: II spatiotemporal expression of genes involved in synthesis and transport of lactate in ovine conceptuses.

Lactate, an abundant molecule in fetal fluids and blood of mammalian species is often overlooked as a metabolic waste product generated during pregnancy. Most of the glucose and fructose consumed by ovine conceptuses is converted to lactate, but proteins involved in lactate metabolism and transport have not been investigated. This study characterized total lactate produced by ovine conceptuses throughout gestation, as well as expression of mRNAs and proteins involved in lactate metabolism. Lactate increased in abundance in the uterine lumen during the preimplantation period and was more abundant than pyruvate. The abundance of lactate in allantoic and amniotic fluids increased with advancing days of gestation and most abundant on Day 125 of pregnancy (P < 0.05). Lactate dehydrogenase (LDH) subunits A (converts pyruvate to lactate) and B (converts lactate to pyruvate) were expressed by conceptuses throughout gestation. Lactate is transported via monocarboxylic acid transporters SLC16A1 and SLC16A3, both of which were expressed by the conceptus throughout gestation. Additionally, the interplacentomal chorioallantois from Day 126 expressed SLC16A1 and SLC16A3 and transported lactate across the tissue. Hydrocarboxylic acid receptor 1 (HCAR1), a receptor for lactate, was localized to the uterine luminal and superficial glandular epithelia of pregnant ewes throughout gestation, and conceptus trophectoderm during the peri-implantation period of gestation. These results provide novel insights into the spatiotemporal profiles of enzymes, transporters, and receptor for lactate by ovine conceptuses throughout pregnancy.

Metabolic pathways for glucose and fructose: I synthesis and metabolism of fructose by ovine conceptuses.

Fructose, the most abundant hexose sugar in fetal fluids and blood of sheep and other ungulates and cetaceans, is synthesized from glucose via the polyol pathway in trophectoderm and chorion. However, the cell-specific and temporal expression of enzymes for the synthesis and metabolism of fructose in sheep conceptuses (embryo and placental membranes) and placentomes has not been characterized. This study characterized key enzymes involved in fructose synthesis and metabolism by ovine conceptuses throughout pregnancy. Day 17 conceptuses expressed mRNAs for the polyol pathway (SORD and AKR1B1) and glucose and fructose metabolism (HK1, HK2, G6PD, OGT, and FBP), but not those required for gluconeogenesis (G6Pase or PCK). Ovine placentomes also expressed mRNAs for SORD, AKR1B1, HK1, and OGT. Fructose can be metabolized via the ketohexokinase (KHK) pathway and isoforms, KHK-A and KHK-C, were expressed in ovine conceptuses from Day 16 of pregnancy and placentomes during pregnancy in a cell specific manner: KHK-A protein was more abundant in trophectoderm and cotyledons of placentomes, while KHK-C protein was more abundant in endoderm of Day 16 conceptuses and chorionic epithelium in placentomes. Expression of KHK mRNAs in placentomes was greatest at Day 30 of pregnancy (P < 0.05), but not different among days later in gestation. These results provide novel insights into the synthesis and metabolism of fructose via the uninhibited KHK pathway in ovine conceptuses to generate ATP via the TCA cycle, as well as substrates for the pentose cycle, hexosamine biosynthesis pathway and one-carbon metabolism required for conceptus development throughout pregnancy.

Hip sensor location for flash interstitial glucose monitoring system provides adequate clinical accuracy in non-diabetic hypoglycemic dogs.

OBJECTIVE: Flash glucose monitoring systems (FGMS) are frequently used for interstitial glucose monitoring in dogs with diabetes mellitus and are typically placed between the scapulae. We aimed to evaluate the variability between glucose measurements from FGMS placed in 2 locations (between the scapulae and over the hip) in non-diabetic dogs during rapidly induced hypoglycemia. ANIMALS: 24 apparently healthy colony dogs that were subjects in a teaching laboratory. PROCEDURES: Prospective interventional study. FGMS sensors (FreeStyle Libre 14-day system) were placed between the scapulae and over the hip of all dogs. Regular insulin was administered (0.3 u/kg IV) and subsequent hypoglycemia was corrected. Before insulin administration and every 10 minutes over 90 minutes, interstitial glucose was recorded from both locations, and blood glucose was measured with a point-of-care blood glucose monitor (AlphaTRAK 2). RESULTS: There was a constant bias of 5.6 mg/dL (95% limits of agreement: -26.3 to 37.5 mg/dL) between locations, but the proportional bias was not apparent. There was a correlation between FGMS locations (r = 0.731, P = < .001). Sensor site B was clinically accurate with 100% of paired samples within Parkes error grid zones A (83%) and B (17%) but did not meet the criteria for analytical accuracy. CLINICAL RELEVANCE: In this model of induced hypoglycemia in healthy dogs, variation between measurements from FGMS locations was unlikely to have affected the clinical outcome. Placement of FGMS over the hip may be an acceptable alternative to placement between the scapulae, but the utility in hyperglycemic dogs is unknown.

The effects of gestational choline supplementation on cerebellar Purkinje cell number in the sheep model of binge alcohol exposure during the first trimester-equivalent.

Individuals with fetal alcohol spectrum disorders (FASD) incur enduring brain damage and neurodevelopmental impairments from prenatal alcohol exposure (PAE). Preclinical rodent models have demonstrated that choline supplementation during development can reduce the severity of adverse neurodevelopmental consequences of PAE. This study used the sheep model to evaluate dietary choline supplementation during pregnancy as a therapeutic intervention, testing the hypothesis that choline can ameliorate alcohol-induced cerebellar Purkinje cell loss. Pregnant ewes were randomly assigned either to a normal control [NC] group (n = 8), or to groups given intravenous infusions of alcohol (or saline) from gestational days 4-41 (the first trimester-equivalent). A weekly binge-drinking pattern was modeled, with three consecutive days of infusions of saline [SAL], 1.75 g/kg/day alcohol [1.75ALC], or 2.5 g/kg/day alcohol [2.5ALC] followed by four days off. Infused ewes were randomly assigned to receive dietary supplements throughout pregnancy of choline (10 mg/kg/day) or placebo (n = 8 per group). Mean blood alcohol concentrations (BAC) were significantly higher in the 2.5ALC groups (287 mg/dL) than the 1.75ALC groups (197 mg/dL). Lamb cerebella were harvested on postnatal day 180 and processed for stereological counts of Purkinje cells. Both alcohol doses caused significant reductions in Purkinje number relative to NC and SAL-Placebo groups, confirming previous findings. Effects of choline supplementation depended on infusion group: it significantly protected against Purkinje cell loss in the 2.5ALC group, had no effect in the 1.75ALC group, and significantly reduced numbers in the SAL-Choline group (though neither the SAL-Choline nor the SAL-Placebo group differed from the NC group). The protection by choline evident only in the 2.5ALC group suggests that multiple, BAC-dependent mechanisms of cerebellar damage may be activated with alcohol exposure in the first trimester, and that choline may protect against pathogenic mechanisms that emerge at higher BACs. These outcomes extend the evidence that early choline supplementation can mitigate some neurodevelopmental defects resulting from binge-like PAE.

Replacing a Veterinary Physiology Endocrinology Lecture with a Blended Learning Approach Using an Everyday Analogy.

Understanding scientific concepts and processes is critical for veterinary education. This article outlines the impact of blended learning and the use of an analogy on student understanding of the hypothalamic-pituitary-target gland axis over a three-year period. The first-year veterinary physiology course at our institution was modified to incorporate a blended learning approach. An analogy centered around a fast-food restaurant was introduced via an animated video to explain key concepts using an online module. Students completed the module on their own time and class time was optional for asking questions or obtaining clarification as needed. Learning was assessed using the same set of multiple-choice exam questions (MCQs). As hypothesized, students using the online module performed equally well (significantly better for those in the lower quartile) on three summative MCQs to those who received the same information delivered by traditional lecture. Student feedback identified positive aspects regarding blended learning using the analogy, including dynamic visuals, ability to work at their own time and pace, and ease of repeating information. Students cited lack of discipline and poor time management as obstacles to completing the module. Changing the anatomy and physiology of the hypothalamus and pituitary gland from static images and text to an animated video significantly improved student's preference for the blended learning approach. Blended learning and the analogy was preferred by 47% of students over the traditional lecture format (21% preferred traditional lecture and 32% were indifferent) and it was more effective in helping students master this important physiological concept.

Evaluation of a flash glucose monitoring system in nondiabetic dogs with rapidly changing blood glucose concentrations.

BACKGROUND: A flash glucose monitoring system (FGMS; FreeStyle Libre) is useful for monitoring hypoglycemic dogs with diabetes. OBJECTIVE: To assess the utility of this FGMS in dogs with induced hypoglycemia and rapid fluctuations in blood glucose (BG) concentrations. ANIMALS: Twenty-four apparently healthy research (n = 10) and teaching (n = 14) dogs. METHODS: Prospective, observational study performed in tandem with a teaching laboratory. Regular insulin was administered to dogs and resulting hypoglycemia was corrected. Before insulin administration and every 10 minutes over a 90-minute period, serial measurements of interstitial glucose (IG) with FGMS and BG with a portable blood glucose meter (PBGM) and clinical chemistry analyzer concentrations were made. Portable blood glucose meter and FGMS readings were compared to that of the clinical chemistry analyzer. Analytical and clinical accuracy were assessed using ISO 15197:2013 criteria, including Parkes error grid analysis. RESULTS: The proportions of readings in the low BG range (BG <100 mg/dL) for which the test method measurement was within ±15 mg/dL of the reference BG for the PBGM and FGMS were 81.7% (161/197) and 39.1% (72/184), respectively. The proportions of readings for the PBGM and FGMS, which were not likely to affect clinical outcome according to Parkes error grid analysis, were 97.9% (233/238) and 80.1% (177/221), respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: In this model, there was limited agreement between the FGMS and reference standard BG measurements. The FGMS (measuring IG concentrations) was compared to peripheral BG concentrations, not brain-tissue glucose concentrations, and failed to reliably detect hypoglycemia.

Prenatal alcohol exposure and maternal glutamine supplementation alter the mTOR signaling pathway in ovine fetal cerebellum and skeletal muscle.

Prenatal alcohol exposure causes fetal neurodevelopmental damage and growth restriction. Among regions of the brain, the cerebellum is the most vulnerable to developmental alcohol exposure. Despite vast research in the field, there is still a need to identify specific mechanisms by which alcohol causes this damage in order to design effective therapeutic interventions. The mammalian target of rapamycin (mTOR) is known to be associated with axonal regeneration, dendritic arborization, synaptic plasticity, cellular growth, autophagy, and many other cellular processes. Glutamine and glutamine-related amino acids play a key role in fetal development and are known to alter the mTOR pathway; recent research has shown that disturbances in their bioavailability and signaling pathways may mediate adverse effects of prenatal alcohol exposure. This study investigated the role of the mTOR signaling pathway in the fetal cerebellum and skeletal muscle after third trimester-equivalent prenatal alcohol exposure and maternal l-glutamine (GLN) supplementation using a sheep model. Fetal cerebella and skeletal muscles were sampled for Western blot analysis of mTOR and its downstream targets S6 kinase and eukaryotic initiation factor 4E-bindin protein (4E-BP1). The expression of cerebellar phosphorylated mTOR relative to the total mTOR was elevated in the alcohol+GLN group compared to the saline and GLN groups. Alcohol exposure increased the ratio of phosphorylated S6K to total S6K in fetal cerebellum, and no significant effect of GLN supplementation was observed. On contrary, maternal GLN supplementation reduced the activation of mTOR and S6K in fetal skeletal muscle, possibly to make GLN and other amino acids available for use by other organs. These findings suggest prenatal alcohol exposure and maternal GLN supplementation during the third trimester-equivalent alter the mTOR signaling cascade, which plays a possible key role in alcohol-induced developmental damage.

Comparison of analgesic efficacy and fetal effects between transdermal administration of fentanyl and intramuscular administration of buprenorphine in pregnant sheep.

OBJECTIVE: To compare analgesic efficacy and fetal effects between transdermal administration of fentanyl and IM administration of buprenorphine in pregnant sheep. ANIMALS: 12 healthy pregnant ewes. PROCEDURES: Before study initiation, each ewe was confirmed pregnant with a single fetus between 113 and 117 days of gestation. Ewes were randomly assigned to receive buprenorphine (0.01 mg/kg, IM, q 8 h for 48 hours beginning 1 hour before anesthesia induction; n = 6) or fentanyl (a combination of transdermal fentanyl patches sufficient to deliver a dose of 2 µg of fentanyl/kg/h applied between the dorsal borders of the scapulae 24 hours before anesthesia induction; 6). Ewes were anesthetized and underwent a surgical procedure to instrument the fetus with an arterial catheter and place a catheter in utero for collection of amniotic fluid samples. Physiologic variables and behavioral changes indicative of pain were assessed, and amniotic fluid and blood samples from ewes and fetuses were collected for determination of drug concentrations at predetermined times. RESULTS: Both protocols provided acceptable postoperative analgesia with no adverse effects observed in the ewes or fetuses. Compared with the buprenorphine protocol, the fentanyl protocol induced more profound analgesia, decreased the requirement for isoflurane during surgery, and was associated with a shorter anesthesia recovery time. Fetal indices did not differ significantly between the 2 analgesic protocols. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that both protocols provided acceptable analgesia. However, the fentanyl protocol was superior in regard to the extent of analgesia induced, inhalant-sparing effects, and anesthesia recovery time.

A plumber's guide to the cardiovascular system.

Blood flow through the cardiovascular system is governed by the same physical rules that govern the flow of water through domestic plumbing. Using this analogy in a teaching laboratory, a model of the cardiovascular system constructed of pumps and pipes was used to demonstrate the basic interactions of pressure, flow, and resistance in a regulated system, with student volunteers providing the operational actions and regulatory components. The model was used to validate predictions and explore solutions prompted by student discussion. This interactive teaching laboratory provides an engaging experiential exercise that demonstrates regulation of flow and pressure in an intact cardiovascular system with apposite changes in heart rate and resistance. In addition, the system provides strong clinical correlates and illustrates how that regulated system responds to challenges such as heart failure, inappropriate vasodilation, and hemorrhage. The results demonstrate that, with limited practice, the instructor can effectively guide the students to reliably reproduce physiologically appropriate results.

Maternal choline supplementation mitigates alcohol-induced fetal cranio-facial abnormalities detected using an ultrasonographic examination in a sheep model.

Early detection of prenatal alcohol exposure is critical for designing and testing effectiveness of interventional therapeutics. Choline supplementation during and after prenatal alcohol exposure has shown promising benefits in improving outcomes in rodent models and clinical studies. A sheep model of first trimester-equivalent binge alcohol exposure was used in this study to model the dose of maternal choline supplementation used in an ongoing prospective clinical trial involving pregnancies at risk for FASD. Pregnant sheep were randomly assigned to six groups: Saline + Placebo control, Saline + Choline, binge Alcohol + Placebo (light binging), binge Alcohol + Choline, Heavy binge Alcohol + Placebo (heavy binging), and Heavy binge Alcohol + Choline. Ewes received intravenous alcohol or saline on three consecutive days per week from gestation day (GD) 4-41 to mimic a first trimester-equivalent weekend binge-drinking paradigm. Choline (10 mg/kg in the daily food ration) was administered from GD 4 until term. On GD 76, 11 fetal ultrasonographic measurements were collected transabdominally. Heavy binge alcohol exposure reduced fetal Frontothalamic Distance (FTD), Mean Orbital Diameter (MOD), and Mean Lens Diameter (MLD), and increased Interorbital Distance (IOD) and Thalamic Width (TW). Maternal choline supplementation mitigated most of these alcohol-induced effects. Maternal choline supplementation also improved overall fetal femur and humerus bone lengths, compared to their respective placebo groups. Taken together, these results indicate a potential dose-dependent effect that could impact the sensitivity of these ultrasonographic measures in predicting prenatal alcohol exposure. This is the first study in the sheep model to identify biomarkers of prenatal alcohol exposure in utero with ultrasound and co-administration of maternal choline supplementation.

Oxytetracycline concentrations in interstitial fluid from tissue chambers inoculated with Corynebacterium pseudotuberculosis after intramuscular or intrachamber administration in sheep.

OBJECTIVE: To determine oxytetracycline concentrations in plasma and in fluid from Corynebacterium pseudotuberculosis (CPT)-inoculated tissue chambers (used as experimental abscess models) and uninoculated (control) tissue chambers in sheep after IM or local administration of the drug and to investigate whether CPT growth was reduced or eliminated by these treatments. ANIMALS: 10 clinically normal female sheep. PROCEDURES: Sterile tissue chambers were surgically implanted in both paralumbar fossae of each sheep; ≥ 2 weeks later (day -6), 1 randomly selected chamber was inoculated with CPT, and the opposite chamber was injected with sterile growth medium. Sheep received oxytetracycline IM (n = 5) or by percutaneous injection into CPT-inoculated (4) or uninoculated (1) chambers on day 0. Tissue fluid from each chamber and venous blood samples for plasma collection were obtained at predetermined times over 6 days for bacterial counts (tissue chambers) and analysis of oxytetracycline concentrations (tissue chambers and plasma). Sheep were euthanized on day 6. Regional lymph nodes were collected bilaterally from each sheep for culture. RESULTS: Measurable concentrations of oxytetracycline were present in each chamber throughout the study, regardless of administration route or presence of CPT. No CPT growth was detected after the 48-hour time point in inoculated chambers injected with oxytetracycline; however, CPT was isolated from all inoculated chambers throughout the study after IM drug administration. One regional lymph node (ipsilateral to a CPT-inoculated, oxytetracycline-injected chamber with no CPT growth after 48 hours) was culture positive for CPT. CONCLUSIONS AND CLINICAL RELEVANCE: Intralesional administration of oxytetracycline may eliminate growth of CPT locally, but complete elimination of the organism remains difficult.

Pharmacokinetics of tulathromycin in fetal sheep and pregnant ewes.

Macrolides are important antimicrobials frequently used in human and veterinary medicine in the treatment of pregnant women and pregnant livestock. They may be useful for the control of infectious ovine abortion, which has economic, animal health, and human health impacts. In this study, catheters were surgically placed in the fetal vasculature and amnion of pregnant ewes at 115 (±2) days of gestation. Ewes were given a single dose of 2.5 mg/kg tulathromycin subcutaneously, and drug concentrations were determined in fetal plasma, maternal plasma, and amniotic fluid at 4, 8, 12, 24, 36, 48, 72, 144, and 288 hr after drug administration. Pharmacokinetic parameters in maternal plasma were estimated using noncompartmental analysis and were similar to those previously reported in nonpregnant ewes. Tulathromycin was present in fetal plasma and amniotic fluid, indicating therapeutic potential for use against organisms in these compartments, though concentrations were lower than those in maternal plasma. Time-course of drug concentrations in the fetus was quite different than that in the ewe, with plasma concentrations reaching a plateau at 4 hr and remaining at this concentration for the remainder of the sampling period (288 hr), raising questions about how tulathromycin may be transported into or metabolized and eliminated by the fetus.

Maternal choline supplementation in a sheep model of first trimester binge alcohol fails to protect against brain volume reductions in peripubertal lambs.

Fetal alcohol spectrum disorder (FASD) is a leading potentially preventable birth defect. Poor nutrition may contribute to adverse developmental outcomes of prenatal alcohol exposure, and supplementation of essential micronutrients such as choline has shown benefit in rodent models. The sheep model of first-trimester binge alcohol exposure was used in this study to model the dose of maternal choline supplementation used in an ongoing prospective clinical trial involving pregnancies at risk for FASD. Primary outcome measures including volumetrics of the whole brain, cerebellum, and pituitary derived from magnetic resonance imaging (MRI) in 6-month-old lambs, testing the hypothesis that alcohol-exposed lambs would have brain volume reductions that would be ameliorated by maternal choline supplementation. Pregnant sheep were randomly assigned to one of five groups - heavy binge alcohol (HBA; 2.5 g/kg/treatment ethanol), heavy binge alcohol plus choline supplementation (HBC; 2.5 g/kg/treatment ethanol and 10 mg/kg/day choline), saline control (SC), saline control plus choline supplementation (SCC; 10 mg/kg/day choline), and normal control (NC). Ewes were given intravenous alcohol (HBA, HBC; mean peak BACs of ∼280 mg/dL) or saline (SC, SCC) on three consecutive days per week from gestation day (GD) 4-41; choline was administered on GD 4-148. MRI scans of lamb brains were performed postnatally on day 182. Lambs from both alcohol groups (with or without choline) showed significant reductions in total brain volume; cerebellar and pituitary volumes were not significantly affected. This is the first report of MRI-derived volumetric brain reductions in a sheep model of FASD following binge-like alcohol exposure during the first trimester. These results also indicate that maternal choline supplementation comparable to doses in human studies fails to prevent brain volume reductions typically induced by first-trimester binge alcohol exposure. Future analyses will assess behavioral outcomes along with regional brain and neurohistological measures.

Alcohol-Induced Developmental Origins of Adult-Onset Diseases.

Fetal alcohol exposure may impair growth, development, and function of multiple organ systems and is encompassed by the term fetal alcohol spectrum disorders (FASD). Research has so far focused on the mechanisms, prevention, and diagnosis of FASD, while the risk for adult-onset chronic diseases in individuals exposed to alcohol in utero is not well explored. David Barker's hypothesis on Developmental Origins of Health and Disease (DOHaD) suggests that insults to the milieu of the developing fetus program it for adult development of chronic diseases. In the 25 years since the introduction of this hypothesis, epidemiological and animal model studies have made significant advancements in identifying in utero developmental origins of chronic adult-onset diseases affecting cardiovascular, endocrine, musculoskeletal, and psychobehavioral systems. Teratogen exposure is an established programming agent for adult diseases, and recent studies suggest that prenatal alcohol exposure correlates with adult onset of neurobehavioral deficits, cardiovascular disease, endocrine dysfunction, and nutrient homeostasis instability, warranting additional investigation of alcohol-induced DOHaD, as well as patient follow-up well into adulthood for affected individuals. In utero epigenetic alterations during critical periods of methylation are a key potential mechanism for programming and susceptibility of adult-onset chronic diseases, with imprinted genes affecting metabolism being critical targets. Additional studies in epidemiology, phenotypic characterization in response to timing, dose, and duration of exposure, as well as elucidation of mechanisms underlying FASD-DOHaD inter relation, are thus needed to clinically define chronic disease associated with prenatal alcohol exposure. These studies are critical to establish interventional strategies that decrease incidence of these adult-onset diseases and promote healthier aging among individuals affected with FASD.

Merging Clinical Cases, Client Communication, and Physiology to Enhance Student Engagement, Learning, and Skills.

Understanding disease processes, making diagnoses, and guiding clinical therapy are predicated on an understanding of normal physiologic function. However, we have observed that many first-year students fail to appreciate the important role that a clear understanding of normal function plays in becoming well-prepared, practicing veterinarians. Students also struggle with application of basic knowledge to the diagnosis and treatment of disease, as evidenced by poor performance on exam questions requiring application. The purpose of this project was to help students link the physiologic concepts in the classroom with clinical application, as well as to improve their ability to explain those concepts to a client. We found that, as a result of this assignment, students developed a deeper understanding of physiologic processes and their clinical relevance and, subsequently, felt more confident conveying this knowledge to simulated clients. Implementation of this case project has been very well received by the students. Students improved their grasp of the material, and they indicated that the project contributed positively to their motivation to study and learn physiology.

Computed tomography assessment of peripubertal craniofacial morphology in a sheep model of binge alcohol drinking in the first trimester.

Identification of facial dysmorphology is essential for the diagnosis of fetal alcohol syndrome (FAS); however, most children with fetal alcohol spectrum disorders (FASD) do not meet the dysmorphology criterion. Additional objective indicators are needed to help identify the broader spectrum of children affected by prenatal alcohol exposure. Computed tomography (CT) was used in a sheep model of prenatal binge alcohol exposure to test the hypothesis that quantitative measures of craniofacial bone volumes and linear distances could identify alcohol-exposed lambs. Pregnant sheep were randomly assigned to four groups: heavy binge alcohol, 2.5 g/kg/day (HBA); binge alcohol, 1.75 g/kg/day (BA); saline control (SC); and normal control (NC). Intravenous alcohol (BA; HBA) or saline (SC) infusions were given three consecutive days per week from gestation day 4-41, and a CT scan was performed on postnatal day 182. The volumes of eight skull bones, cranial circumference, and 19 linear measures of the face and skull were compared among treatment groups. Lambs from both alcohol groups showed significant reduction in seven of the eight skull bones and total skull bone volume, as well as cranial circumference. Alcohol exposure also decreased four of the 19 craniofacial measures. Discriminant analysis showed that alcohol-exposed and control lambs could be classified with high accuracy based on total skull bone volume, frontal, parietal, or mandibular bone volumes, cranial circumference, or interorbital distance. Total skull volume was significantly more sensitive than cranial circumference in identifying the alcohol-exposed lambs when alcohol-exposed lambs were classified using the typical FAS diagnostic cutoff of ≤10th percentile. This first demonstration of the usefulness of CT-derived craniofacial measures in a sheep model of FASD following binge-like alcohol exposure during the first trimester suggests that volumetric measurement of cranial bones may be a novel biomarker for binge alcohol exposure during the first trimester to help identify non-dysmorphic children with FASD.

Effects of oxymorphone hydrochloride or hydromorphone hydrochloride on minimal alveolar concentration of desflurane in sheep.

OBJECTIVE: To establish the minimum alveolar concentration (MAC) of desflurane and evaluate the effects of 2 opioids on MAC in sheep. ANIMALS: 8 adult nulliparous mixed-breed sheep. PROCEDURES: A randomized crossover design was used. Each sheep was evaluated individually on 2 occasions (to allow assessment of the effects of each of 2 opioids), separated by a minimum of 10 days. On each occasion, sheep were anesthetized with desflurane in 100% oxygen, MAC of desflurane was determined, oxymorphone (0.05 mg/kg) or hydromorphone (0.10 mg/kg) was administered IV, and MAC was redetermined. Physiologic variables and arterial blood gas and electrolyte concentrations were measured at baseline (before MAC determination, with end-tidal desflurane concentration maintained at 10%) and each time MAC was determined. Timing of various stages of anesthesia was recorded for both occasions. RESULTS: Mean ± SEM MAC of desflurane was 8.6 ± 0.2%. Oxymorphone or hydromorphone administration resulted in significantly lower MAC (7.6 ± 0.4% and 7.9 ± 0.2%, respectively). Cardiac output at MAC determination for desflurane alone and for desflurane with opioid administration was higher than that at baseline. No difference was identified among hematologic values at any point. Effects of oxymorphone and hydromorphone on durations of various stages of anesthesia did not differ significantly. CONCLUSIONS AND CLINICAL RELEVANCE: MAC of desflurane in nulliparous adult sheep was established. Intravenous administration of oxymorphone or hydromorphone led to a decrease in MAC; however, the clinical importance of that decrease was minor relative to the effect in other species.

Formate metabolism in fetal and neonatal sheep.

By virtue of its role in nucleotide synthesis, as well as the provision of methyl groups for vital methylation reactions, one-carbon metabolism plays a crucial role in growth and development. Formate, a critical albeit neglected component of one-carbon metabolism, occurs extracellularly and may provide insights into cellular events. We examined formate metabolism in chronically cannulated fetal sheep (gestation days 119-121, equivalent to mid-third trimester in humans) and in their mothers as well as in normal full-term lambs. Plasma formate levels were much higher in fetal lamb plasma and in amniotic fluid (191 ± 62 and 296 ± 154 µM, respectively) than in maternal plasma (33 ± 13 µM). Measurements of folate, vitamin B12, and homocysteine showed that these high formate levels could not be due to vitamin deficiencies. Elevated formate levels were also found in newborn lambs and persisted to about 8 wk of age. Formate was also found in sheep milk. Potential precursors of one-carbon groups were also measured in fetal and maternal plasma and in amniotic fluid. There were very high concentrations of serine in the fetus (∼1.6 mM in plasma and 3.5 mM in the amniotic fluid) compared with maternal plasma (0.19 mM), suggesting increased production of formate; however, we cannot rule out decreased formate utilization. Dimethylglycine, a choline metabolite, was also 30 times higher in the fetus than in the mother.

Maternal L-glutamine supplementation prevents prenatal alcohol exposure-induced fetal growth restriction in an ovine model.

Prenatal alcohol exposure is known to cause fetal growth restriction and disturbances in amino acid bioavailability. Alterations in these parameters can persist into adulthood and low birth weight can lead to altered fetal programming. Glutamine has been associated with the synthesis of other amino acids, an increase in protein synthesis and it is used clinically as a nutrient supplement for low birth weight infants. The aim of this study was to explore the effect of repeated maternal alcohol exposure and L-glutamine supplementation on fetal growth and amino acid bioavailability during the third trimester-equivalent period in an ovine model. Pregnant sheep were randomly assigned to four groups, saline control, alcohol (1.75-2.5 g/kg), glutamine (100 mg/kg, three times daily) or alcohol + glutamine. In this study, a weekend binge drinking model was followed where treatment was done 3 days per week in succession from gestational day (GD) 109-132 (normal term ~147). Maternal alcohol exposure significantly reduced fetal body weight, height, length, thoracic girth and brain weight, and resulted in decreased amino acid bioavailability in fetal plasma and placental fluids. Maternal glutamine supplementation successfully mitigated alcohol-induced fetal growth restriction and improved the bioavailability of glutamine and glutamine-related amino acids such as glycine, arginine, and asparagine in the fetal compartment. All together, these findings show that L-glutamine supplementation enhances amino acid availability in the fetus and prevents alcohol-induced fetal growth restriction.

Effects of all three trimester moderate binge alcohol exposure on the foetal hippocampal formation and olfactory bulb.

OBJECTIVE: Pre-natal alcohol exposure results in injury to the hippocampus and olfactory bulb,but currently there is no consensus on the critical window of vulnerability. This study tested thehypothesis that pre-natal exposure to a moderate dose of alcohol during all three trimesterequivalentsalters development of the hippocampal formation and olfactory bulb in an ovinemodel, where all brain development occurs pre-natally as it does in humans.Research design and methods: Pregnant sheep were divided into saline control and abinge drinking groups (alcohol dose 1.75 g kg(-1); mean peak blood alcohol concentration189 + 19mg dl(-1)). OUTCOME AND RESULTS: The density, volume and total cell number were not different betweengroups for the dentate gyrus, pyramidal cells in the CA1 and CA2/3 fields and mitral cells in theolfactory bulb. CONCLUSIONS: A moderate dose of alcohol administered in a binge pattern throughout gestationdoes not alter cell numbers in the hippocampus or olfactory bulb and exposure during thethird trimester-equivalent is required for hippocampal injury, unless very high doses of alcoholare administered. This has important implications in establishing the sensitivity of imagingmodalities such as MRI in which volumetric measures are being studied as biomarkers forpre-natal alcohol exposure.