Large-scale analysis of sheep rumen metagenome profiles captured by reduced representation sequencing reveals individual profiles are influenced by the environment and genetics of the host

BACKGROUND

Producing animal protein while reducing the animal's impact on the environment, e.g., through improved feed efficiency and lowered methane emissions, has gained interest in recent years. Genetic selection is one possible path to reduce the environmental impact of livestock production, but these traits are difficult and expensive to measure on many animals. The rumen microbiome may serve as a proxy for these traits due to its role in feed digestion. Restriction enzyme-reduced representation sequencing (RE-RRS) is a high-throughput and cost-effective approach to rumen metagenome profiling, but the systematic (e.g., sequencing) and biological factors influencing the resulting reference based (RB) and reference free (RF) profiles need to be explored before widespread industry adoption is possible.

RESULTS

Metagenome profiles were generated by RE-RRS of 4,479 rumen samples collected from 1,708 sheep, and assigned to eight groups based on diet, age, time off feed, and country (New Zealand or Australia) at the time of sample collection. Systematic effects were found to have minimal influence on metagenome profiles. Diet was a major driver of differences between samples, followed by time off feed, then age of the sheep. The RF approach resulted in more reads being assigned per sample and afforded greater resolution when distinguishing between groups than the RB approach. Normalizing relative abundances within the sampling Cohort abolished structures related to age, diet, and time off feed, allowing a clear signal based on methane emissions to be elucidated. Genus-level abundances of rumen microbes showed low-to-moderate heritability and repeatability and were consistent between diets.

CONCLUSIONS

Variation in rumen metagenomic profiles was influenced by diet, age, time off feed and genetics. Not accounting for environmental factors may limit the ability to associate the profile with traits of interest. However, these differences can be accounted for by adjusting for Cohort effects, revealing robust biological signals. The abundances of some genera were consistently heritable and repeatable across different environments, suggesting that metagenomic profiles could be used to predict an individual's future performance, or performance of its offspring, in a range of environments. These results highlight the potential of using rumen metagenomic profiles for selection purposes in a practical, agricultural setting.

Combining host and rumen metagenome profiling for selection in sheep: prediction of methane, feed efficiency, production, and health traits

BACKGROUND

Rumen microbes break down complex dietary carbohydrates into energy sources for the host and are increasingly shown to be a key aspect of animal performance. Host genotypes can be combined with microbial DNA sequencing to predict performance traits or traits related to environmental impact, such as enteric methane emissions. Metagenome profiles were generated from 3139 rumen samples, collected from 1200 dual purpose ewes, using restriction enzyme-reduced representation sequencing (RE-RRS). Phenotypes were available for methane (CH4) and carbon dioxide (CO2) emissions, the ratio of CH4 to CH4 plus CO2 (CH4Ratio), feed efficiency (residual feed intake: RFI), liveweight at the time of methane collection (LW), liveweight at 8 months (LW8), fleece weight at 12 months (FW12) and parasite resistance measured by faecal egg count (FEC1). We estimated the proportion of phenotypic variance explained by host genetics and the rumen microbiome, as well as prediction accuracies for each of these traits.

RESULTS

Incorporating metagenome profiles increased the variance explained and prediction accuracy compared to fitting only genomics for all traits except for CO2 emissions when animals were on a grass diet. Combining the metagenome profile with host genotype from lambs explained more than 70% of the variation in methane emissions and residual feed intake. Predictions were generally more accurate when incorporating metagenome profiles compared to genetics alone, even when considering profiles collected at different ages (lamb vs adult), or on different feeds (grass vs lucerne pellet). A reference-free approach to metagenome profiling performed better than metagenome profiles that were restricted to capturing genera from a reference database. We hypothesise that our reference-free approach is likely to outperform other reference-based approaches such as 16S rRNA gene sequencing for use in prediction of individual animal performance.

CONCLUSIONS

This paper shows the potential of using RE-RRS as a low-cost, high-throughput approach for generating metagenome profiles on thousands of animals for improved prediction of economically and environmentally important traits. A reference-free approach using a microbial relationship matrix from log₁₀ proportions of each tag normalized within cohort (i.e., the group of animals sampled at the same time) is recommended for future predictions using RE-RRS metagenome profiles.

Genetic parameter analysis of bareness and tail traits in New Zealand sheep

Physical traits that improve welfare and disease outcomes for sheep are becoming increasingly important due to both increased climate challenges and societal expectations. Such traits include tail length, the amount of skin (versus wool) on the underside of the tail, and the area of no-wool (hair) on the belly and breech areas (surrounding the anus) of the animal. An industry dataset consisting of records from individual stud breeders and industry progeny tests was available to estimate the genetic parameters associated with these traits and to investigate the potential for within-breed genetic selection. The heritability estimate for tail length was 0.68 ± 0.01 when breed was not fitted, and 0.63 ± 0.01 when breed was fitted. Similar trends were observed for breech and belly bareness which had heritability estimates around 0.50 (± 0.01). The estimates for these bareness traits are both higher than previous reports from animals of the same age. There was, however, between breed variation in the starting point for these traits, with some breeds having significantly longer tails and a wooly breech and belly, and limited variability. Overall, the results of this study show that flocks exhibiting some variation will be able to make rapid genetic progress in selecting for bareness and tail length traits, and therefore have the potential to make progress towards a sheep that is easier to look after and suffers fewer welfare insults. For those breeds that showed limited within-breed variation, outcrossing may be required to introduce genotypes that exhibit shorter tail length and bareness of belly and breech to increase the rate of genetic gain. Whatever approach is taken by the industry, these results support that genetic improvement can be used to breed "ethically improved sheep".

Potential of in-plant intramuscular fat predictions to enable sheep breeders to incorporate consumer preferences in breeding programmes

The inclusion of eating quality traits in sheep genetic improvement programmes is desirable. Intramuscular fat (IMF) plays a key role in ensuring consumer satisfaction when eating lamb, but genetic progress for IMF is constrained by a lack of routine data collection. This study investigated the potential for IMF predictor traits to substitute for measured IMF in genetic improvement programmes. Carcass and predicted IMF (near-infrared estimated IMF and marbling score) data were available on 10,113 New Zealand lambs, 1678 of which also had measured chemical IMF on a slice of M. longissimus lumborum on which the predictions of IMF had been made. Genetic antagonisms were observed between carcass lean traits and IMF. The genetic correlation between the predictors and measured IMF approached one, indicating that predictors of IMF can be used in genetic improvement programmes. Through using selection indexes, simultaneous increases in IMF and the existing terminal selection index are possible, provided all traits are measured. This study highlights the importance and potential of predicted IMF to achieve genetic improvement in traits of importance to consumers.

Genetic parameters for residual feed intake, methane emissions, and body composition in New Zealand maternal sheep

There is simultaneous interest in improving the feed efficiency of ruminant livestock and reducing methane (CH₄) emissions. The relationship (genetic and phenotypic) between feed efficiency (characterized as residual feed intake: RFI) and greenhouse gases [methane (CH₄) and carbon dioxide (CO₂)] traits in New Zealand (NZ) maternal sheep has not previously been investigated, nor has their relationship with detailed estimates of body composition. To investigate these relationships in NZ maternal sheep, a feed intake facility was established at AgResearch Invermay, Mosgiel, NZ in 2015, comprising automated feeders that record individual feeding events. Individual measures of feed intake, feeding behavior (length and duration of eating events), and gas emissions (estimated using portable accumulation chambers) were generated on 986 growing maternal ewe lambs sourced from three pedigree recorded flocks registered in the Sheep Improvement Limited database (www.sil.co.nz). Additional data were generated from a subset of 591 animals for body composition (estimated using ultrasound and computed tomography scanning). The heritability estimates for RFI, CH₄, and CH₄/(CH₄+CO₂) were 0.42 ± 0.09, 0.32 ± 0.08, and 0.29 ± 0.06, respectively. The heritability estimates for the body composition traits were high for carcass lean and fat traits; for example, the heritability for visceral fat (adjusted for body weight) was 0.93 ± 0.19. The relationship between RFI and CH₄ emissions was complex, and although less feed eaten will lead to a lowered absolute amount of CH₄ emitted, there was a negative phenotypic and genetic correlation between RFI and CH₄/(CH₄+CO₂) _of −0.13 ± 0.03 and −0.41 ± 0.15, respectively. There were also genetic correlations, that were different from zero, between both RFI and CH₄ traits with body composition including a negative correlation between the proportion of visceral fat in the body and RFI (−0.52 ± 0.16) and a positive correlation between the proportion of lean in the body and CH₄ (0.54 ± 0.12). Together the results provide the first accurate estimates of the genetic correlations between RFI, CH₄ emissions, and the body composition (lean and fat) in sheep. These correlations will need to be accounted for in genetic improvement programs.

Genomic Tools for the Identification of Loci Associated with Facial Eczema in New Zealand Sheep

Facial eczema (FE) is a significant metabolic disease that affects New Zealand ruminants. Ingestion of the mycotoxin sporidesmin leads to liver and bile duct damage, which can result in photosensitisation, reduced productivity and death. Strategies used to manage the incidence and severity of the disease include breeding. In sheep, there is considerable genetic variation in the response to FE. A commercial testing program is available for ram breeders who aim to increase tolerance, determined by the concentration of the serum enzyme, gamma-glutamyltransferase 21 days after a measured sporidesmin challenge (GGT21). Genome-wide association studies were carried out to determine regions of the genome associated with GGT21. Two regions on chromosomes 15 and 24 are reported, which explain 5% and 1% of the phenotypic variance in the response to FE, respectively. The region on chromosome 15 contains the β-globin locus. Of the significant SNPs in the region, one is a missense variant within the haemoglobin subunit β (HBB) gene. Mass spectrometry of haemoglobin from animals with differing genotypes at this locus indicated that genotypes are associated with different forms of adult β-globin. Haemoglobin haplotypes have previously been associated with variation in several health-related traits in sheep and warrant further investigation regarding their role in tolerance to FE in sheep. We show a strategic approach to the identification of regions of importance for commercial breeding programs with a combination of discovery, statistical and biological validation. This study highlights the power of using increased density genotyping for the identification of influential genomic regions, combined with subsequent inclusion on lower density genotyping platforms.

Relationships between intramuscular fat percentage and fatty acid composition in M. longissimus lumborum of pasture-finished lambs in New Zealand

This paper reports relationships between fatty acids (FAs) and intramuscular fat (IMF)% in M. longissimus lumborum samples from 108 pasture-fed ewe lambs. Samples ranged in IMF from 1 to 6%. Relationships between %FA with total IMF% were mainly linear with percentages of saturated and monounsaturated FAs (MUFA), including trans-FAs, increasing and polyunsaturated FAs decreasing as IMF% increased. Normalized FA content data at 5.5% relative to 1.5% IMF, showed the highest relative increase for C14:0 as rates of endogenous synthesis increase with higher IMF deposition. This can be related to enhanced C12:0 elongation and lower rates of C14:0 desaturation, supported by a preferential desaturation of C18:1 trans-11 and C18:0 compared with C14:0 and C16:0 as IMF increased. The greatest normalized increase after C14:0 was anteisoC17:0 followed by other branched chain FAs and then trans-MUFA and C18:2 cis-9,trans-11. Finally, C22:6 and C22:5 showed higher relative increase than C20:5 indicating greater rates of elongation and desaturation past C20:5 at higher levels of fatness.

Relationships among Consumer Liking, Lipid and Volatile Compounds from New Zealand Commercial Lamb Loins

Loin sections (m. Longissimus lumborum) were collected at slaughter from forty-eight lamb carcasses to evaluate consumer-liking scores of six types of typical New Zealand commercial lamb and to understand the possible underlying reasons for those ratings. A consumer panel (n = 160) evaluated tenderness, juiciness, flavor liking, and overall liking of the different types of lamb loins. Consumer scores differed among the types of lamb meat for all the evaluated attributes (p < 0.05). Further segmentation based on overall liking scores showed two consumer clusters with distinct ratings. Correlation and external preference map analyses indicated that one consumer cluster (n = 75) liked lamb types that had lower total lipid content, a lower proportion of branched-chain fatty acids, oleic and heptadecanoic acids; and a higher proportion of polyunsaturated fatty acids and volatile compounds (green and fruity descriptors). Consumer liking of the other segment (n = 85) was less influenced by fatty acids and volatiles, except hexanoic, heptanoic and octanoic acids (rancid, fatty, and sweaty descriptors). Thus, the fatty acid profile and the volatile compounds derived from their oxidation upon cooking seem to be a stronger driver of consumer liking of lamb for some consumers than others.

Fatty Acid Composition and Volatile Profile of M. longissimus thoracis from Commercial Lambs Reared in Different Forage Systems

Animal production factors can affect the fatty acid and volatile profile of lamb meat. The fatty acid and volatile composition of the M. longissimus thoracis was evaluated from 150 lambs from 10 groups of commercial lambs that differed in age, sex, diet and breed, from three farms, which represent typical forage lamb production systems in New Zealand. The meat from 4-month-old composite lambs slaughtered at weaning had a similar polyunsaturated to saturated fatty acid ratio compared to 6- to 8-month-old composite lambs, but a greater ratio than that of 12-month-old Merino lambs (p < 0.05), with all ratios being lower than the recommended ≥0.45. All lamb production systems produced meat with an omega-6 to omega-3 ratio below 1.5, well below the recommended ratio ≤ 4.0. Meat from 4-month-old lambs had higher C12:0, C14:0 and C16:0 and lower C18:0, reflecting the composition of the milk diet, resulting in higher atherogenic index than meat from other animal groups, while meat from 12-month-old Merino lambs, with lower content of polyunsaturated fatty acids, showed higher thrombogenic index. Meat from lambs processed at weaning contained the greatest concentration of eicosapentaenoic and docosahexaenoic acids, which would qualify as a 'source' or 'good source' of these target fatty acids based on the Commission of Regulation of the European Union or the Food Standards Australia New Zealand guidelines, respectively. Volatiles were extracted from the headspace of raw lean meat and 36 volatile compounds were identified. The abundance of carbon disulphide, isododecane, heptanal, 2,5-hexanediol and 3-octanone and pentanoic, octanoic, nonanoic and heptanoic acids was similar between all groups of lambs. Meat from 12-month-old Merino lambs had low abundance of acetic, propanoic, butanoic and hexanoic acids, and hexanal, octanal and dimethyl sulphide. For 6- to 8-month-old composite lambs, hexanal, octanal and nonanal were present at higher relative abundance in meat from lambs that grazed on chicory than perennial ryegrass. The significant differences in the fatty acid and volatile profiles in meat from 12-month-old Merino lambs compared with lambs slaughtered at weaning or further grazed on red clover, chicory or mixed pasture may result in distinctive nutritional value and lamb flavour.

Consumer liking of M. longissimus lumborum from New Zealand pasture-finished lamb is influenced by intramuscular fat

Palatability of meat is known to be affected by intramuscular fat (IMF), but the effect in relatively low-fat New Zealand lamb is unknown. This study evaluated the eating quality of 108 loins (M. longissimus lumborum) from a single flock of ewe-lambs. Loins ranged from 1.09-5.68% IMF and were stratified into 6 groups: 1.65, 2.12, 2.65, 3.20, 3.58 and 4.40%. Consumers' (n = 165) overall liking of lamb increased significantly at around 3% IMF, achieving maximum scores at 4% IMF. One consumer cluster (n = 111) showed a linear increase in overall liking with increasing IMF%, regarded as 'IMF lovers: the more the better', while a second cluster (n = 54) preferred 2.5-3.5% IMF, described as 'IMF optimizers: just the right amount'. IMF% was modestly correlated (~ + 0.25) with all sensory attributes except juiciness. Liking scores were modestly correlated with monounsaturated (~ + 0.25) and polyunsaturated (~ - 0.20) fatty acids. Results suggest aiming for IMF% levels in New Zealand lamb beyond 3% to maximize eating quality for premium markets in particular.

Panic results in unique molecular and network changes in the amygdala that facilitate fear responses

Recurrent panic attacks (PAs) are a common feature of panic disorder (PD) and post-traumatic stress disorder (PTSD). Several distinct brain regions are involved in the regulation of panic responses, such as perifornical hypothalamus (PeF), periaqueductal gray, amygdala and frontal cortex. We have previously shown that inhibition of GABA synthesis in the PeF produces panic-vulnerable rats. Here, we investigate the mechanisms by which a panic-vulnerable state could lead to persistent fear. We first show that optogenetic activation of glutamatergic terminals from the PeF to the basolateral amygdala (BLA) enhanced the acquisition, delayed the extinction and induced the persistence of fear responses 3 weeks later, confirming a functional PeF-amygdala pathway involved in fear learning. Similar to optogenetic activation of PeF, panic-prone rats also exhibited delayed extinction. Next, we demonstrate that panic-prone rats had altered inhibitory and enhanced excitatory synaptic transmission of the principal neurons, and reduced protein levels of metabotropic glutamate type 2 receptor (mGluR2) in the BLA. Application of an mGluR2-positive allosteric modulator (PAM) reduced glutamate neurotransmission in the BLA slices from panic-prone rats. Treating panic-prone rats with mGluR2 PAM blocked sodium lactate (NaLac)-induced panic responses and normalized fear extinction deficits. Finally, in a subset of patients with comorbid PD, treatment with mGluR2 PAM resulted in complete remission of panic symptoms. These data demonstrate that a panic-prone state leads to specific reduction in mGluR2 function within the amygdala network and facilitates fear, and mGluR2 PAMs could be a targeted treatment for panic symptoms in PD and PTSD patients.

Application of Hyperspectral imaging to predict the pH, intramuscular fatty acid content and composition of lamb M. longissimus lumborum at 24h post mortem

Cost-effective, rapid and objective measurement of lamb quality on a routine basis is an important step for lamb value chains wishing to manage lamb product quality. Hyperspectral imaging (HSI) technology has shown promise as a solution for objective non-invasive prediction of meat quality. The performance of HSI applied 24h post mortem to lamb M. longissimus lumborum (LL) within a processing plant environment was assessed over two sampling years to evaluate its suitability for an objective lamb meat quality assurance tool. Calibration and validation steps were undertaken to evaluate HSI prediction performance for predicting fatty acid content and composition (n=1020 lambs) and pH (n=2406 lambs). Practical considerations of reference meat quality data quality and validation strategies are discussed. HSI can be used to predict meat quality parameters of lamb LL with varying accuracy levels, but ongoing calibration and validation across seasons is required to improve robustness of HSI for objective non-invasive assessment of lamb meat quality.

Pre-clinical medical students' perceptions of their patient safety skills in a simulated emergency department

OBJECTIVES

Patient safety has emerged as an important topic for inclusion in medical curricula. However, there is limited literature describing how medical students are taught, learn and self-assess patient safety skills. The present study aimed to seek pre-clinical medical students' perceptions of (i) their individual performance at a range of safety skills; and (ii) how they define patient safety in a simulated ED.

METHODS

Data were collected in the form of questionnaire responses at the end of the Bond University Simulated ED activity in October 2014. The simulated ED is a session for pre-clinical medical students prior to their clinical rotations, aimed at preparing them for the clinical environment. Likert scale and short answer responses were used to describe students' perceptions of their safety skills and to identify themes related to patient safety.

RESULTS

Seventy-eight out of 92 students completed the questionnaires (85% response rate). The majority of students thought their patients were safe from adverse events during their shift. However, students' perception of patient safety was wide-ranging and demonstrated a number of misconceptions. The most frequent strategies employed by students to ensure patient safety were asking for help from nursing staff or senior doctors, ensuring good communication with the patient and checking allergies before administering medication.

CONCLUSION

Students had a favourable opinion of their own safety skills. However, answers to free text question revealed misconceptions about the nature of patient safety despite significant teaching on this topic.

Pediatric misophonia with comorbid obsessive-compulsive spectrum disorders

OBJECTIVE

Misophonia is a potentially debilitating condition characterized by increased sensitivity to specific sounds, which cause subsequent behavioral and emotional responses. The nature, clinical phenomenology and etiology of misophonia remain unclear, and misophonic clinical presentations are not currently accounted for by existing psychiatric or audiological disorders.

METHOD

We present a case of pediatric misophonia in the context of comorbid obsessive-compulsive disorder and Tourette's syndrome.

RESULTS

Given the interrelationships among obsessive-compulsive spectrum disorders and misophonia, these disorders may share underlying pathophysiology, particularly within the dopaminergic and serotonergic neural systems. Clinical (i.e., treatment) and theoretical implications are discussed.

Genetic relationships between dagginess, breech bareness, and wool traits in New Zealand dual-purpose sheep

Genetic and phenotypic parameters were estimated for dagginess, breech, wool, and fiber traits from approximately 29,500 progeny born in 2009 and 2010 in New Zealand dual-purpose ram breeding sheep flocks. Dagginess is adherence of fecal matter to the wool, and this study investigates the genetic and phenotypic correlations between dagginess and breech and wool traits. Estimates for heritability were moderate (0.21 to 0.44) for the following traits: dag score at 3 and 8 mo (DAG3, DAG8), breech bareness, wool length, wool bulk (BULK), mean fiber diameter, mean fiber diameter SD, mean fiber diameter CV, curvature (CURV), weaning weight at 3 mo, and autumn BW. Heritability estimates for fleece weight at 12 mo and proportion of medullated fibers were high (0.49 and 0.53, respectively). Dag score at 3 mo and DAG8 had low genetic and phenotypic correlations with all traits. Breech bareness had positive genetic and phenotypic correlations with CURV and BULK and mostly negative genetic correlations with all other wool traits. In summary the quantity and attributes of wool were not primary causative factors in fecal accumulation, leaving fecal consistency and composition as the major factors.

Infant mortality and intra-household competition in the Northern Islands of Orkney, Scotland, 1855-2001

This study applies principles from the theory of household life cycles to the study of early childhood mortality in the population of the Northern Orkney Islands, Scotland. The primary hypothesis is that unfavorable household economic conditions resulting from changes in household demographic composition increase the risk of death for children under the age of 5 years because of limited resources and intra-household competition. We apply Cox proportional hazards models to nearly 5,000 linked birth and death records from the Northern Orkney Islands, Scotland, from the period 1855 to 2001. The dependent variable is the child's risk of death before age 5. Findings suggest that children in households with unfavorable age compositions face higher risk of death. This elevated risk of death continues once heterogeneity among children, islands, and households is controlled. Results also show differential risk of death for male children, children of higher birth orders, and twin births. The analyses present evidence for intra-household competition in this historic setting. The most convincing evidence of competition is found in the effects of household consumer/producer ratios and twinning on child mortality risks.

Household-level predictors of the presence of servants in Northern Orkney, Scotland, 1851-1901

Servants were an important part of the northwestern European household economy in the preindustrial past. This study examines household-level characteristics that are predictive of the presence of rural servants using data from Orkney, Scotland. The number of servants present in a household is related to household composition, landholding size, and the marital status of the household head. In addition, the sex of the particular servant hired reveals that the labor of male and female servants is not fungible. The sex of the servant hired is related to the ratio of male and female household members of working age, the occupation of the head, household composition, and the size of the household's landholding.

Topographical distribution of corticotropin-releasing factor type 2 receptor-like immunoreactivity in the rat dorsal raphe nucleus: co-localization with tryptophan hydroxylase

Corticotropin-releasing factor (CRF) and CRF-related neuropeptides are involved in the regulation of stress-related physiology and behavior. Members of the CRF family of neuropeptides bind to two known receptors, the CRF type 1 (CRF₁) receptor, and the CRF type 2 (CRF₂) receptor. Although the distribution of CRF₂ receptor mRNA expression has been extensively studied, the distribution of CRF₂ receptor protein has not been characterized. An area of the brain known to contain high levels of CRF₂ receptor mRNA expression and CRF₂ receptor binding is the dorsal raphe nucleus (DR). In the present study we investigated in detail the distribution of CRF₂ receptor immunoreactivity throughout the rostrocaudal extent of the DR. CRF₂ receptor-immunoreactive perikarya were observed throughout the DR, with the highest number and density in the mid-rostrocaudal DR. Dual immunofluorescence revealed that CRF₂ receptor immunoreactivity was frequently co-localized with tryptophan hydroxylase, a marker of serotonergic neurons. This study provides evidence that CRF₂ receptor protein is expressed in the DR, and that CRF₂ receptors are expressed in topographically organized subpopulations of cells in the DR, including serotonergic neurons. Furthermore, these data are consistent with the hypothesis that CRF₂ receptors play an important role in the regulation of stress-related physiology and behavior through actions on serotonergic and non-serotonergic neurons within the DR.

Anxiety-like behavior is modulated by a discrete subpopulation of interneurons in the basolateral amygdala

The basolateral amygdala (BL) is a putative site for regulating anxiety, where inhibition and excitation respectively lead to decreases and increases in anxiety-like behaviors. The BL contains local networks of GABAergic interneurons that are subdivided into classes based on neurochemical content, and are hypothesized to regulate unique functional responses of local glutamatergic projection neurons. Recently it was demonstrated that lesioning a portion of the BL interneuronal population, those interneurons that express neurokinin1 receptors (NK(1r)), resulted in anxiety-like behavior. In the current study, these NK(1r) expressing cells of the BL are further phenotypically characterized, demonstrating approximately 80% co-expression with GABA thus confirming them as GABAergic interneurons. These NK(1r) interneurons also colocalize with two distinct populations of BL interneurons as defined by the neuropeptide content. Of the NK(1r) positive cells, 41.8% are also positive for neuropeptide Y (NPY) and 39.7% of the NK(1r) positive cells are also positive for cholecystokinin (CCK). In addition to enhancing the phenotypic characterization, the extent to which the NK(1r) cells of amygdala nuclei contribute to anxiety-like responses was also investigated. Lesioning the NK(1r) expressing interneurons, with a stable form of substance P (SSP; the natural ligand for NK(1r)) coupled to the targeted toxin saporin (SAP), in the anterior and posterior divisions of the BL was correlated to increased anxiety-like behaviors compared to baseline and control treated rats. Furthermore the phenotypic and regional selectivity of the lesions was also confirmed.

Investigations into the GDF8 g+6723G-A polymorphism in New Zealand Texel sheep

This work investigated effects of carrying 0, 1, or 2 copies of the A allele resulting from the g+6723G-A transition in growth differentiation factor gene (GDF8) in New Zealand Texel-cross sheep at different lamb ages and carcass weights. Two Texel-cross sires carrying 1 copy of the A allele were mated to approximately 200 ewes carrying 0, 1, or 2 copies of the A allele. A total of 187 progeny were generated and genotyped to determine whether they were carrying 0, 1, or 2 copies of the A allele. The progeny were assigned to 1 of 4 slaughter groups balanced for the 3 genotypes, sex, and sire. The 4 groups were slaughtered commercially when their average BW (across all progeny in the slaughter group) reached 33, 40, 43, and 48 kg, respectively. Measurements of BW, and carcass dimensions and yield were made on all animals using Viascan (a commercial 2-dimensional imaging system that estimates lean content of the carcass as a percentage of total carcass weight). Additional measurements were made on the fourth slaughter group, which was computed tomography scanned at each slaughter time point to obtain 4 serial measures of lean and fat as estimated from the computed tomography images. The A allele did not have an effect on any BW traits. The A allele was associated with increased muscle and decreased fat across the variety of measures of muscling and fat, explaining between 0.2 and 1.1 of a residual SD unit. Estimates for an additive effect were significant and were positive for muscle and negative for fat traits. No dominance effect estimates (positive or negative) were significant. There was no significant interaction between A allele number and carcass weight or slaughter group for any trait. This is the first systematic study of the effect of the A allele copy number over a range of carcass weights (13 to 20 kg) and ages and results suggest the size of the effect across these endpoints is proportionately the same. Testing for the A allele therefore offers breeders the potential to improve rates of genetic gain for lean-meat yield across most production systems.

Response of Bark and Woodboring Beetles to Host Volatiles and Wounding on Western Juniper

In central Oregon, management of western juniper (Juniperus occidentalis var. occidentalis Hook.) has included use of prescribed fire and mechanical removal. After these treatments, several species of bark and woodboring beetles have been observed on treated trees and also occasionally on trees outside management areas, suggesting that these insects might contribute to juniper mortality. In this 2-year (2002–2003) study, we identified bark and woodboring beetles that attack western juniper along with associated beetle predators and examined whether these insects can be manipulated for use in juniper management. Using funnel traps and sticky traps on trees wounded by pruning or treated with host volatiles (juniper berry oil, cade oil, and ethanol) that may attract insects, we captured beetles in the families Buprestidae, Cerambycidae, and Scolytidae (20 species in 17 genera) and known predators in the families Cleridae and Trogositidae (8 species in 7 genera). Cedar bark beetles (Phloeosinus spp.) were the most prevalent insects captured on trees treated with host volatiles and/or wounded. Treatments that included ethanol plus wounding were most attractive to these beetles. However, there was no obvious insect-caused damage or mortality of treated trees in either year of this study.

The bone-muscle ratio of fetal lambs is affected more by maternal nutrition during pregnancy than by maternal size

Bone formation and loss are related to the strain imposed on bone by muscle forces. Bone mineral content (BMC) and lean mass (LM) of fetal lambs was determined at day 140 of pregnancy in 8 groups of ewes, which were of either large or small body size, on either high (ad libitum) or maintenance pasture intake from day 21 of pregnancy, or carrying either singletons or twins. BMC and LM (using DXA scanning) of fetal hindquarters/spine were corrected to leg length. BMC and LM were less in twin than singleton groups (P < 0.001). Large ewes on high intake produced single fetuses with a (group mean) BMC/LM ratio that was higher (P < 0.002) than that in fetuses of large ewes with singletons on maintenance intake or twins on either high or maintenance intakes, the ratios of which were not different. In single fetuses from small ewes on high intake, the BMC/LM ratio was higher than those from small ewes with singletons on maintenance intake or twins on either high or maintenance intakes, the ratios of which were not different. The ratio was not different in singleton fetuses of ewes on high intake, whether they were large or small. Different fetal environments resulted in a given amount of muscle being associated with a higher or lower bone mass. Dietary intake during pregnancy was more important than maternal size in affecting the ratio. We conclude that intrauterine environmental factors may be important in determining bone mass postnatally, and possibly later in life.

Meat quality traits were unaffected by a quantitative trait locus affecting leg composition traits in Texel sheep

A QTL affecting leg muscle and fat traits has been identified within the New Zealand Texel population. The QTL maps to a region on OAR 2 with a two-marker haplotype test established at markers BULGE20 and BM81124. These markers encompass the likely position of Growth Differentiation Factor 8 (GDF8). The pleiotropic effects of this QTL on meat quality traits are tested. Objective measures of meat quality including pH, color (L*, a*, and b*), and tenderness (as assessed by Warner-Bratzler shear force measurements) were assessed on longissimus and semi-membranosus muscles of 540 progeny from six Texel sires. Four of these sires were subsequently identified as segregating for leg muscle and fat traits. For these segregating sires, comparison of progeny that had inherited the favorable haplotype from their sire with those that had received the alternate haplotype revealed no significant differences in the meat quality traits assessed. This finding suggests that the muscling QTL does not have pleiotropic effects on meat quality. A general scan for meat quality QTL was carried out using genotype data for eight markers from FCB128 to RM356 flanking 122cM of OAR 2 using Haley-Knott regression. This analysis revealed two QTL for a single sire. A QTL detected in the region of Marker INRA40 for color L* mapped to a site close to the muscling QTL, but there was evidence to suggest it is at a distinct locus. The QTL in the region of Marker RM356 might map distal to Marker RM356, as no peak was observed. This QTL, which seems to affect pH, color a*, color b*, and Warner-Bratzler shear measurements, requires further characterization.

Serotonergic systems associated with arousal and vigilance behaviors following administration of anxiogenic drugs

Serotonergic systems play important roles in modulating behavioral arousal, including behavioral arousal and vigilance associated with anxiety states. To further our understanding of the neural systems associated with increases in anxiety states, we investigated the effects of multiple anxiogenic drugs on topographically organized subpopulations of serotonergic neurons using double immunohistochemical staining for c-Fos and tryptophan hydroxylase combined with topographical analysis of the rat dorsal raphe nucleus (DR). Anxiogenic drugs with diverse pharmacological properties including the adenosine receptor antagonist caffeine, the serotonin 5-HT2A/2C receptor agonist m-chlorophenyl piperazine (mCPP), the alpha2-adrenoreceptor antagonist yohimbine, and the benzodiazepine receptor partial inverse agonist N-methyl-beta-carboline-3-carboxamide (FG-7142) induced increases in behavioral arousal and vigilance behaviors consistent with an increase in anxiety state. In addition, these anxiogenic drugs, excluding yohimbine, had convergent actions on an anatomically-defined subset of serotonergic neurons within the middle and caudal, dorsal subdivision of the DR. High resolution topographical analysis revealed that at the mid-rostrocaudal level, caffeine and FG-7142 had convergent effects on c-Fos expression in serotonergic neurons that were restricted to a previously undefined region, which we have named the shell region of the dorsal part of the dorsal raphe nucleus (DRDSh), that overlaps the anatomical border between the dorsal part of the dorsal raphe nucleus, the ventral part of the dorsal raphe nucleus (DRV), and the ventrolateral part of the dorsal raphe nucleus (DRVL). Retrograde tracing methods revealed that DRDSh contains large numbers of neurons projecting to the basolateral amygdaloid nucleus, a forebrain structure important for emotional appraisal and modulation of anxiety-related physiological and behavioral responses. Together these findings support the hypothesis that there is a functional topographical organization in the DR and are consistent with the hypothesis that anxiogenic drugs have selective actions on a subpopulation of serotonergic neurons projecting to a distributed central autonomic and emotional motor control system regulating anxiety states and anxiety-related physiological and behavioral responses.

A directed search in the region of GDF8 for quantitative trait loci affecting carcass traits in Texel sheep1

A directed search for QTL affecting carcass traits was carried out in the region of growth differentiation factor 8 (GDF8, also known as myostatin) on ovine chromosome 2 in seven Texel-sired half-sib families totaling 927 progeny. Weights were recorded at birth, weaning, ultrasound scanning, and slaughter. Ultrasonic measures of LM cross-sectional dimensions and s.c. fat above the LM were made, with the same measurements made on the LM after slaughter. Following slaughter, linear measurements of carcass length and width were made on all carcasses, and legs and loins from 540 lambs were dissected. Genotyping was carried out using eight microsatellite markers from FCB128 to RM356 on OAR 2 and analyzed using Haley-Knott regression. There was no evidence for QTL for growth rates or linear carcass traits. There was some evidence for QTL affecting LM dimensions segregating in some sire families, although it was not consistent between ultrasound and carcass measures of the same traits. There was strong and consistent evidence for a QTL affecting muscle and fat traits in the leg that mapped between markers BM81124 and BULGE20 for the four sires that were heterozygous in this region, but not for the three sires that were homozygous. The size of the effect varied across the four sires, ranging from 0.5 to 0.9 of an adjusted SD for weight-adjusted leg muscle traits, and ranging from 0.6 to 1.2 of an adjusted SD for weight-adjusted leg fat traits. The clearest effect shown was for multivariate analysis combining all leg muscle and fat traits analyzed across sires, where the -log(10) probability was 14. Animals carrying the favorable haplotype had 3.3% more muscle and 9.9% less fat in the leg relative to animals carrying other haplotypes. There was evidence for a second peak in the region of marker TEXAN2 for one sire group. It seems that a QTL affecting muscle and fat traits exists within the New Zealand Texel population, and it maps to the region of GDF8 on OAR2.

Use of the oxford multilocus sequence typing protocol and sequencing of the flagellin short variable region to characterize isolates from a large outbreak of waterborne Campylobacter sp. strains in Walkerton, Ontario, Canada

The Walkerton (Ontario, Canada) outbreak of waterborne Escherichia coli O157:H7 and Campylobacter jejuni was quite limited in both space and time, making it a good model for exploring the utility of different typing and subtyping methods for the characterization of relationships among isolates of these organisms. We have extended previous work with these organisms through analysis by the Oxford multilocus sequence typing (MLST) and the flagellin short variable region (fla-SVR) sequencing methods. Additional isolates not epidemiologically related to the Walkerton outbreak have also been included. Both sequencing methods identified and differentiated between Walkerton outbreak strains 1 and 2. When these strains were compared with isolates that were not part of the outbreak, the information produced by the fla-SVR method more often correlated with epidemiological findings than that produced by MLST, though both methods were required for optimal discrimination. The MLST data were more relevant in terms of the overall population structure of the organisms. Both mutation and recombination appeared to be responsible for generating diversity among the isolates tested.

Ratiometry of transmembrane voltage-sensitive fluorescent dye emission in hearts

Transmembrane voltage-sensitive fluorescence measurements are limited by baseline drift that can obscure changes in resting membrane potential and by motion artifacts that can obscure repolarization. Voltage-dependent shift of emission wavelengths may allow reduction of drift and motion artifacts by emission ratiometry. We have tested this for action potentials and potassium-induced changes in resting membrane potential in rabbit hearts stained with di-4-ANEPPS [Pyridinium, 4-(2-(6-(dibutylamino)-2-naphthalenyl) ethenyl)-1-(3-sulfopropyl)-, hydroxide, inner salt] using laser excitation (488 nm) and a two-photomultiplier tube system or spectrofluorometer (resolution of 500-1,000 Hz and <1 mm). Green and red emissions produced upright and inverted action potentials, respectively. Ratios of green emission to red emission followed action potential contours and exhibited larger fractional changes than either emission alone (P < 0.001). The largest changes and signal-to-noise ratio (signal/noise) were obtained with numerator wavelengths of 525-550 nm and denominator wavelengths of 650-700 nm. Ratiometry lessened drift 56-66% (P < 0.015) and indicated decreases in resting membrane potential. Ratiometry lessened motion artifacts and increased magnitudes of deflections representing phase-zero depolarizations relative to total deflections by 123-188% in intact hearts (P < 0.02). Durations of action potentials at different pacing rates, temperatures, and potassium concentrations were independent of whether they were measured ratiometrically or with microelectrodes (P > or = 0.65). The ratiometric calibration slope was 0.017/100 mV and decreased with time. Thus emission ratiometry lessens the effects of motion and drift and indicates resting membrane potential changes and repolarization.

Errors caused by combination of Di-4 ANEPPS and Fluo3/4 for simultaneous measurements of transmembrane potentials and intracellular calcium

Intracellular calcium concentration and transmembrane potentials are two important measurements used to study the mechanisms of cardiac activity. Fluorescent dyes have been used to measure these separately but not simultaneously in cardiac tissue. Fluo-3 and Fluo-4 (a recently improved version of Fluo-3) have been used to measure changes in intracellular calcium concentration and Di-4 ANEPPS has been used to measure transmembrane potentials. This paper addresses the feasibility of using these fluorescent dyes together in order to measure transmembrane potentials and intracellular calcium concentration simultaneously. For the dyes to be used simultaneously, their respective fluorescence spectra must be sufficiently separated in wavelength in order to allow them to be separated by optical filters or spectrographs. An apparatus was constructed to measure the dyes' spectra in a fluorescence imaging chamber as well as in an isolated perfused rabbit heart. The measured spectra were mathematically modeled in order to assess the spectral overlap error under different conditions. Error graphs were constructed which may help researchers select optical filters and dye concentrations that will result in an acceptable error.

Reversal of impaired oxidative phosphorylation and calcium overloading in the skeletal muscle mitochondria of CHF-146 dystrophic hamsters

Membrane-mediated excessive intracellular calcium accumulation (EICA) and diminished cellular energy production are the hallmarks of dystrophic pathobiology in Duchenne and Becker muscular dystrophies. We reported reversal of respiratory damage and Ca(2+)-overloading in the in vitro cardiac mitochondria from CHF-146 dystrophic hamsters (DH) with hereditary muscular dystrophy (Bhattacharya et al., 1993). Here we studied respiratory dysfunctions in the skeletal muscle mitochondria from young and old DH, and whether these abnormalities can be reversed by reducing [Ca2+] in the isolation medium, thereby lowering intramitochondrial Ca(2+)-overloading. Age- and sex-matched CHF-148 albino normal hamsters (NH) served as controls. As an index of EICA and cellular degeneration, Ca and Mg levels were assayed in the skeletal muscle and mitochondria. Mitochondria from young and old DH, isolated without EDTA (BE medium), revealed poor coupling of oxidative phosphorylation, diminished stimulated oxygen consumption rate, and lower respiratory control ratio and ADP/O ratios, compared to NH. Incorporation of 10 mM EDTA (Bo medium) in the isolation medium restored mitochondrial functions of the dystrophic organelles to a near-normal level, and reduced Ca(2+)-overloading. The mitochondrial Ca level in DH was significantly higher than in NH, irrespective of the medium. However, compared to Bo medium, the dystrophic organelles isolated in BE medium had lower Ca levels and markedly improved oxidative phosphorylation as seen in NH. Muscle Ca contents in the young and old DH were elevated relative to NH, showing a positive correlation with the increased mitochondrial Ca(2+)-sequestration. Dystrophic muscle also revealed Ca deposition with an abundance of Ca(2+)-positive and necrotic myofibers by light microscopy, and intramitochondrial Ca(2+)-overloading by electron microscopy, respectively. However, Mg levels in the muscle and mitochondria did not alter with age or dystrophy. These data parallel our observations in the heart, and suggest that functional impairments and Ca(2+)-overloading also occur in the skeletal muscle mitochondria of DH, and are indeed reversible if EICA is regulated by slow Ca(2+)-channel blocker therapy (Johnson and Bhattacharya, 1993).

Correlation of gallbladder ejection fraction with pathologic grade for chronic inflammation

BACKGROUND

The purpose of this study is to define the sensitivity and specificity of the gallbladder ejection fraction (GBEF) for identifying patients with various grades of histologically proven chronic cholecystitis.

METHODS

Of 693 consecutive patients who had a scintigraphic GBEF determination at Baptist Medical Center of Oklahoma, 161 subsequently had a cholecystectomy at the same institution. Pathologic material was reassessed by one outside blinded reviewer, who graded the intensity of the inflammation present on a 0 (absent) to 3 (most severe) scale.

RESULTS

The least square mean maximum GBEF was 23.7% for those with grade 0, 9.6% for those with grade 3, and 13.9% for those with cholesterolosis. If a normal value for GBEF is set at > 30%, the sensitivity for detecting grade 1, 2, or 3 disease was 84%, and the specificity was 26%. For grade 3 disease alone, the sensitivity was 100%, and the specificity was 26%.

CONCLUSIONS

The GBEF is sensitive but not specific for chronic inflammation of the gallbladder. The GBEF appears to be useful as a screening examination in the appropriate clinical setting.

Reduced sarcolemmal dystrophin distribution and upregulation of utrophin in the cardiac and skeletal muscles of CHF-146 dystrophic hamsters

Abnormalities in the dystrophic gene product, dystrophin, have been implicated in initiating the primary membrane defect and excessive intracellular calcium accumulation (EICA), which play fundamental pathogenic roles in hereditary muscular dystrophy (HMD). Two other cytoskeletal proteins, spectrin and utrophin, bear remarkable structural and functional homologies to dystrophin. CHF-146 strain dystrophic hamsters (DH), like patients with Duchenne muscular dystrophy (DMD), die prematurely from cardiopulmonary insufficiency, focal myonecrosis, and progressive degeneration of the cardiac and skeletal muscles with EICA. Although DH present a suitable model for HMD, there are controversies concerning their dystrophin and utrophin status. Using immunocytochemistry and Western blotting, we studied dystrophin, spectrin and utrophin anomalies in the cardiac and skeletal muscles of 6-mo-old male DH. Age- and sex-matched CHF-148 strain albino normal hamsters (NH) served as controls. Sarcolemmal dystrophin staining was much weaker and interruptive in the DH. The densitometric analysis of the immunoblots revealed that dystrophin is reduced in DH by 83% in cardiac muscle (p < 0.0001), and by 50% in skeletal muscle (p < 0.0001). We conclude that sarcolemmal dystrophin distribution is markedly reduced and discontinuous in the cardiac and skeletal muscles of DH, with simultaneous upregulation of utrophin and a varied degree of spectrin labelling. This observation suggests that reduced sarcolemmal dystrophin is associated with membrane hyperpermeability, which leads to progressive muscle degeneration via EICA and segmental necrosis in DH. As in DMD, utrophin appears to play an important compensatory role in hamster dystrophinopathy.

Laparoscopy. Gasless vs. CO2 pneumoperitoneum

OBJECTIVE

To compare gasless laparoscopy with conventional laparoscopy using CO2 pneumoperitoneum.

STUDY DESIGN

Women undergoing bilateral laparoscopic tubal coagulation (LTC) were randomly assigned to one of two laparoscopy procedures: (1) a gasless laparoscopy system consisting of an intraabdominal fan retractor and electrically powered mechanical arm, and (2) standard CO2 pneumoperitoneum laparoscopy. The two laparoscopic procedures were compared on the basis of intraoperative visualization, operation duration, procedural difficulty, ventilatory parameters, hemodynamic stability, and postoperative pain and nausea.

RESULTS

Significant disadvantages for the surgeon (increased technical difficulty, poorer visualization, longer operative times) and patient (greater postoperative pain and nausea) were seen with the gasless system. Because of these findings, the study was prematurely terminated after only 18 patients had participated. Intraoperative ventilatory and hemodynamic parameters were more stable in the gasless laparoscopy groups; however, the differences were not clinically significant in this population of healthy patients.

CONCLUSION

The markedly increased technical difficulty and absence of clear clinical benefits for the healthy patient led to the conclusion that laparoscopy with CO2 pneumoperitoneum is preferable for routine LTC and most laparoscopic procedures in the pelvis. Gasless laparoscopy may be of benefit for the fragile patient with a compromised cardiovascular system who may suffer complications from hypercarbenemia.

Behavioral components of marital satisfaction: an individualized assessment approach

This study examined the extent to which spousal behaviors, obtained through a daily checklist of marital activities individualized along an importance dimension, related to global and daily marital satisfaction. Eighty-two marital couples completed daily checklists of spousal behaviors for 7 days using either an individualized or a standardized assessment method. The results demonstrated that the individualized measures of daily behavioral events were significantly related to global and daily measures of marital satisfaction and discriminated distressed from nondistressed spouses. Although the individualized method did not correlate with marital satisfaction to a significantly greater degree than the standardized method, the individualized assessment approach provides a valid, viable, and cost-effective alternative for assessing daily spousal events that relate to marital satisfaction.

Evaluation of U.S. Public Health Service programs. Organization and management

This article provides an overview of evaluation in the Public Health Service (PHS) of the U.S. Department of Health and Human Services. The kinds of evaluation activities are outlined with illustrations of recently completed studies. The overview includes information on resources, policies, and management of evaluations conducted by the various PHS agencies and programs. In particular, the department's new efforts to better disseminate evaluation results through the Internet are described. The article concludes with a discussion of future prospects of how PHS evaluations will play a role in implementation of the Government Performance and Results Act (GPRA).

Behavioral components of marital satisfaction: an individualized assessment approach

This study examined the extent to which spousal behaviors, obtained through a daily checklist of marital activities individualized along an importance dimension, related to global and daily marital satisfaction. Eighty-two marital couples completed daily checklists of spousal behaviors for 7 days using either an individualized or a standardized assessment method. The results demonstrated that the individualized measures of daily behavioral events were significantly related to global and daily measures of marital satisfaction and discriminated distressed from nondistressed spouses. Although the individualized method did not correlate with marital satisfaction to a significantly greater degree than the standardized method, the individualized assessment approach provides a valid, viable, and cost-effective alternative for assessing daily spousal events that relate to marital satisfaction.

A comparative evaluation of bedside capillary blood glucose monitoring devices designed for hospital use

Capillary blood glucose monitoring devices (CBGMs) that incorporate "wipeless" technology recently have been designed and marketed for hospital use. Our objective was to evaluate three such devices for accuracy and precision, comparing them to a popular device that utilizes older technology and to a reference standard. Blood glucose level was simultaneously determined on the CBGMs and a reference standard. Results were analyzed for precision by performing repeated measurements of a single sample and for accuracy across the entire range of determinations. Clinically relevant subsets of the entire range also were determined and arbitrarily defined as low (< 60 mg/dL), normal (60 to 140 mg/dL), high (141 to 300 mg/dL), and very high (> 300 mg/dL). We found that accuracy and precision of these devices varied considerably. Lack of accuracy was particularly evident upon analysis of the clinically relevant subset ranges of blood glucose levels. Consequently, routine evaluation of CBGMs should include analysis of clinically relevant subset ranges of blood glucose levels. The marked differences in accuracy and precision between CBGMs that are currently.

Postoperative abscess mimicked by Surgicel

Laparoscopic cholecystectomy is a very common surgery in many hospitals today. Thrombogenic agents are important for visualization, especially since the gallbladder fossa is a difficult bleeding source to control. Surgicel, oxidized regenerated cellulose, is a bioabsorbable thrombogenic which given the proper clinical context can be indistinguishable from an abscess on postoperative CT scans.

Effects of accumbens DALA microinjections on brain stimulation reward and behavioral activation in intact and 6-OHDA treated rats

The effects of bilateral nucleus accumbens microinjections of d-ala-met-enkephalinamide (DALA) were assessed in behavioral activation and lateral hypothalamic self-stimulation (LHSS) rate-frequency curve-shift paradigms in normal and accumbens 6-OHDA (4.0 micrograms) treated rats. Microinjections of DALA (2.5 micrograms/microliters) in the behavioral activation paradigm had little effect on normal activity; however, DALA administered to 6-OHDA treated rats produced a significant overall increase in locomotion. The 6-OHDA DALA-induced locomotion effect peaked at 2 weeks after 6-OHDA treatment and then returned to baseline levels by week 5 post-treatment. Using LHSS, DALA tested over a range of doses (2.5, 5, 10, 20 micrograms/microliters) displayed a weak biphasic reward effect only at the highest dose, which was characterized by an initial suppression followed by an elevation. DALA significantly depressed initial operant motor/performance in LHSS in a dose dependent fashion. Microinjections of the normally ineffective low dose of DALA (2.5 micrograms/microliters) following accumbens 6-OHDA treatment produced a significant LHSS reward decrease 2 weeks post-treatment, while LHSS motor/performance was relatively unaffected. Results are discussed in terms of opiate-dopamine and limbic-motor interactions.

Pulse oximetry signals local anesthetic-induced methemoglobinemia

An otherwise healthy patient with a fractured mandible was scheduled to undergo an open reduction under general anesthesia. Just before transport to the operating room, bimaxillary arch bars were placed under local anesthesia with 4% prilocaine and 1:200,000 epinephrine. Although induction of anesthesia and nasoendotracheal intubation were uneventful, pulse oximetry values fell to 89% despite adequate ventilation and an inspired oxygen concentration of 50%. Inquiry by the anesthesiologist and arterial blood gas measurements revealed that methemoglobinemia had developed in response to the large amount 576 mg) of prilocaine administered. A total of 150 mg of methylene blue administered in two doses corrected the problem. The oral surgeon, having recently switched to prilocaine because of a manufacturer's recall of lidocaine, was unaware of the potential of prilocaine to cause this disorder.

Reversal of impaired oxidative phosphorylation and calcium overloading in the in vitro cardiac mitochondria of CHF-146 dystrophic hamsters with hereditary muscular dystrophy

Membrane-mediated excessive intracellular calcium accumulation (EICA), and diminished cellular energy charge are invariably present in the myocardium of CHF-146 strain dystrophic hamsters (DH) with hereditary muscular dystrophy (HMD) and hypertrophic cardiomyopathy (HC). Therefore, we investigated respiratory dysfunctions and Ca2+ overloading in the isolated cardiac mitochondria from young and old DH, and whether these abnormalities can be reversed by controlling EICA in the in vitro mitochondria upon chelating excessive Ca2+ from the isolation medium with EDTA. Age- and sex-matched CHF-148 strain albino normal hamsters (NH) served as the disease controls. As an index of membrane-mediated EICA and chronic cellular degeneration, Ca and Mg concentrations were quantitated in the ventricular myocardium and in the cardiac mitochondria harvested in two different isolation media. Mitochondria from young and old DH, isolated in the absence of 10 mM EDTA (B0 medium), revealed poor coupling of oxidative phosphorylation, diminished stimulated oxygen consumption rate, and lower respiratory control and ADP/O ratios, than those seen in NH. However, incorporation of 10 mM EDTA in the isolation medium (B medium) restored the mitochondrial functions and reduced massive Ca(2+)-overloading in the dystrophic organelles. Ca concentration in the in vitro mitochondria from DH was significantly higher than in NH, irrespective of the composition of the isolation medium and age of the hamsters. Furthermore, the dystrophic organelles isolated in B medium had a much lower Ca concentration, and markedly improved oxidative phosphorylation as seen in the cardiac mitochondria from NH, compared to those prepared using B0 medium.(ABSTRACT TRUNCATED AT 250 WORDS)

The magnetic resonance appearance of extraperitoneal bowel perforation: a case report

The use of magnetic resonance imaging (MRI) for abdominal and gastrointestinal imaging has been quite limited, when compared to its utilization in other organ systems. We present an interesting case of extraperitoneal bowel perforation, which was diagnosed by magnetic resonance (MR). Extraperitoneal bowel perforation is frequently a confusing and difficult diagnosis to make. The multiplanar imaging capability and unique sensitivity of MR to fluid enabled a specific diagnosis to be made in this challenging case.

Regulation of membrane-mediated chronic muscle degeneration in dystrophic hamsters by calcium-channel blockers: diltiazem, nifedipine and verapamil

Membrane-mediated excessive intracellular calcium accumulation (EICA) is a fundamental pathogenetic event associated with chronic muscle degeneration in patients with Duchenne muscular dystrophy (DMD), and in animals with hereditary muscular dystrophy (HMD). Because of potential Ca(2+)-channel blocking properties, we investigated the relative efficacies of chronic diltiazem (DTZM) (50 mg/kg/d), nifedipine (NFDN) (6 mg/kg/d), and verapamil (VPML) (25 mg/kg/d) therapies in reducing EICA and improving dystrophic pathobiology beginning in 30-day-old male BIO-14.6 strain dystrophic hamsters (DH). Each agent, and sterile distilled water as vehicle control, was given in a single daily oral dose for 180 days to four groups each of DH and BIO-F1B strain normal hamsters (NH). Plasma [Ca] and [Mg]; plasma aldolase (ALD), creatine kinase (CK), and lactate dehydrogenase (LDH) activities; relative cardiac hypertrophy and relative soleus hypertrophy; tissue [Ca] and [Mg] of the heart and rectus femoris muscle, histology of rectus femoris, and overall mortality rate were quantitated. Muscle Mg was not modified in DH, or by any of these agents. NFDN produced significant edema in the soleus and myocardium. During the 6-month therapeutic trial, 45% DH and 18% NH died on VPML, 27% DH and 9% NH on NFDN, and 20% DH controls on distilled water, but none on DTZM; suggesting that DTZM treated DH lived longer than DH controls. Relative efficacy in regulating EICA in both the cardiac and skeletal muscles; plasma ALD, CK, and LDH; and improving associated dystrophic pathobiology was found to be DTZM >>> NFDN > VPML. DTZM appears to be the most effective and safest agent in mitigating EICA in cardiac and skeletal muscles, efflux of intracellular enzymes, histopathology of dystrophic muscle with sporadic necrosis, and chronic muscle degeneration in DH with HMD. DTZM therapy also halted the high morbidity and mortality associated with the dystrophic pathobiology inherent in DH.

Proximity injuries: correlation with results of extremity arteriography

The results of 170 emergency arteriography procedures in 142 patients who had sustained extremity injuries near major arteries were correlated with the findings from a physical examination conducted prior to arteriography. Radiographically demonstrable significant arterial injuries, which usually required surgical repair, were present at 42 of the 170 injury sites (25%). Major physical findings suggestive of arterial injury were noted at 105 of 170 sites (62%). Arteriography demonstrated a significant injury in 40 (38%) of these 105 injury sites, representing 95% of all major arterial injuries. Among the 65 injury sites without any suggestive major physical finding, only two were associated with a significant vascular injury at arteriography (3%) (5% of all 42 arterial injuries). At each of these 65 injury sites, the decision to perform emergency arteriography was based solely on the proximity of the wound to a major artery. In spite of this very low yield in the subgroup of 51 patients without major physical findings, emergency arteriography is still routinely requested for extremity injuries at the authors' institutions. The validity of this policy, a possible reason for its development, and its effect on patient disposition are examined.