Lesion Heterogeneity on High-Field Susceptibility MRI Is Associated with Multiple Sclerosis Severity

BACKGROUND AND PURPOSE

Susceptibility MR imaging contrast variations reflect alterations in brain iron and myelin content, making this imaging tool relevant to studies of multiple sclerosis lesion heterogeneity. In this study, we aimed to characterize the relationship of high-field, susceptibility contrasts in multiple sclerosis lesions to clinical outcomes.

MATERIALS AND METHODS

Twenty-four subjects with multiple sclerosis underwent 7T MR imaging of the brain, disability examinations, and a fatigue inventory. The inverse of T2* relaxation time (R2*), frequency, and relative susceptibility (from quantitative susceptibility mapping) were analyzed in 306 white matter lesions.

RESULTS

Most lesions were hypointense on R2* (88% without a rim, 5% with). Lesions that were hyperintense on quantitative susceptibility mapping were more frequent in relapsing-remitting than in progressive multiple sclerosis (54% versus 35%, P = .018). Hyperintense lesion rims on quantitative susceptibility maps were more common in progressive multiple sclerosis and patients with higher levels of disability and fatigue. Mean lesion R2* was inversely related to disability and fatigue and significantly reduced in progressive multiple sclerosis. Relative susceptibility was lower in lesions in progressive multiple sclerosis (median, -0.018 ppm; range, -0.070 to 0.022) than in relapsing-remitting MS (median, -0.010 ppm; range, -0.062 to 0.052; P = .003).

CONCLUSIONS

A progressive clinical phenotype and greater disability and fatigue were associated with lower R2* and relative susceptibility values (suggestive of low iron due to oligodendrocyte loss) and rimmed lesions (suggestive of chronic inflammation) in this multiple sclerosis cohort. Lesion heterogeneity on susceptibility MR imaging may help explain disability in multiple sclerosis and provide a window into the processes of demyelination, oligodendrocyte loss, and chronic lesion inflammation.

Effects of drought-affected corn and nonstarch polysaccharide enzyme inclusion on nursery pig growth performance

The effectiveness of carbohydrase enzymes has been inconsistent in corn-based swine diets; however, the increased substrate of nonstarch polysaccharides in drought-affected corn may provide an economic model for enzyme inclusion, but this has not been evaluated. A total of 360 barrows (PIC 1050 × 337, initially 5.85 kg BW) were used to determine the effects of drought-affected corn inclusion with or without supplementation of commercial carbohydrases on growth performance and nutrient digestibility of nursery pigs. Initially, 34 corn samples were collected to find representatives of normal and drought-affected corn. The lot selected to represent the normal corn had a test weight of 719.4 kg/m3, 15.0% moisture, and 4.2% xylan. The lot selected to represent drought-affected corn had a test weight of 698.8 kg/m3, 14.3% moisture, and 4.7% xylan. After a 10-d acclimation period postweaning, nursery pigs were randomly allotted to 1 of 8 dietary treatments in a completely randomized design. Treatments were arranged in a 2 × 4 factorial with main effects of corn (normal vs. drought affected) and enzyme inclusion (none vs. 100 mg/kg Enzyme A vs. 250 mg/kg Enzyme B vs. 100 mg/kg Enzyme A + 250 mg/kg Enzyme B). Both enzymes were included blends of β-glucanase, cellulose, and xylanase (Enzyme A) or hemicellulase and pectinases (Enzyme B). Pigs were fed treatment diets from d 10 to 35 postweaning in 2 phases. Feed and fecal samples were collected on d 30 postweaning to determine apparent total tract digestibility of nutrients. The nutrient concentrations of normal and drought-affected corn were similar, which resulted in few treatment or main effects differences of corn type or enzyme inclusion. No interactions were observed (P > 0.10) between corn source and enzyme inclusion. Overall (d 10 to 35), treatments had no effect on ADG or ADFI, but enzyme A inclusion tended to improve (P < 0.10; 0.74 vs. 0.69) G:F, which was primarily driven by the improved feed efficiency (0.76 vs. 0.72; P < 0.05) of pigs fed Enzyme A in Phase 2 (d 10 to 25 postweaning) and was likely a result of improved xylan utilization. In conclusion, drought stress did not alter the nonstarch polysaccharide concentration of corn beyond xylan concentration, so it was not surprising that enzyme inclusion showed little benefit to nursery pig growth performance. However, improved feed efficiency of pigs fed diets containing Enzyme A from d 10 to 25 postweaning warrants further investigation

Transcript profiles in longissimus dorsi muscle and subcutaneous adipose tissue: a comparison of pigs with different postweaning growth rates

Although most pigs recover rapidly from stresses associated with the transition of weaning, a portion of the population lags behind their contemporaries in growth performance. The underlying biological and molecular mechanisms involved in postweaning differences in growth performance are poorly understood. The objective of this experiment was to use transcriptional profiling of skeletal muscle and adipose tissue to develop a better understanding of the metabolic basis for poor weaned-pig transition. A total of 1,054 pigs was reared in commercial conditions and weighed at birth, weaning, and 3 wk postweaning. Transition ADG (tADG) was calculated as the ADG for the 3-wk period postweaning. Nine pigs from both the lowest 10th percentile (low tADG) and the 60th to 70th percentile (high tADG) were harvested at 3 wk postweaning. Differential expression analysis was conducted in longissimus dorsi muscle (LM) and subcutaneous adipose tissue using RNA-Seq methodology. In LM, 768 transcripts were differentially expressed (DE), 327 with higher expression in low tADG and 441 with higher expression in high tADG pigs (q < 0.10). Expression patterns measured in LM by RNA-Seq were verified in 30 of 32 transcripts using quantitative PCR. No DE transcripts were identified in adipose tissue. To identify biological functions potentially underlying the effects of tADG on skeletal muscle metabolism and physiology, functional annotation analysis of the DE transcripts was conducted using DAVID and Pathway Studio analytic tools. The group of DE genes with lower expression in LM of low tADG pigs was enriched in genes with functions related to muscle contraction, glucose metabolism, cytoskeleton organization, muscle development, and response to hormone stimulus (enrichment score > 1.3). The list of DE genes with higher expression in low tADG LM was enriched in genes with functions related to protein catabolism (enrichment score > 1.3). Analysis of known gene-gene interactions identified possible regulators of these differences in gene expression in LM of high and low tADG pigs; these include forkhead box O1 (FOXO1), growth hormone (GH1), and the glucocorticoid receptor (NR3C1). Differences in gene expression between poor transitioning pigs and their contemporaries indicate a shift to decreased protein synthesis, increased protein degradation, and reduced glucose metabolism in the LM of low tADG pigs.

Role for the M1 Muscarinic Acetylcholine Receptor in Top-Down Cognitive Processing Using a Touchscreen Visual Discrimination Task in Mice

The M1 muscarinic acetylcholine receptor (mAChR) subtype has been implicated in the underlying mechanisms of learning and memory and represents an important potential pharmacotherapeutic target for the cognitive impairments observed in neuropsychiatric disorders such as schizophrenia. Patients with schizophrenia show impairments in top-down processing involving conflict between sensory-driven and goal-oriented processes that can be modeled in preclinical studies using touchscreen-based cognition tasks. The present studies used a touchscreen visual pairwise discrimination task in which mice discriminated between a less salient and a more salient stimulus to assess the influence of the M1 mAChR on top-down processing. M1 mAChR knockout (M1 KO) mice showed a slower rate of learning, evidenced by slower increases in accuracy over 12 consecutive days, and required more days to acquire (achieve 80% accuracy) this discrimination task compared to wild-type mice. In addition, the M1 positive allosteric modulator BQCA enhanced the rate of learning this discrimination in wild-type, but not in M1 KO, mice when BQCA was administered daily prior to testing over 12 consecutive days. Importantly, in discriminations between stimuli of equal salience, M1 KO mice did not show impaired acquisition and BQCA did not affect the rate of learning or acquisition in wild-type mice. These studies are the first to demonstrate performance deficits in M1 KO mice using touchscreen cognitive assessments and enhanced rate of learning and acquisition in wild-type mice through M1 mAChR potentiation when the touchscreen discrimination task involves top-down processing. Taken together, these findings provide further support for M1 potentiation as a potential treatment for the cognitive symptoms associated with schizophrenia.

Levels and trends of smokeless tobacco use among youth in countries of the World Health Organization South-East Asia Region

BACKGROUND

At least two rounds of the Global Youth Tobacco Survey (GYTS) have been completed in most of the countries in the World Health Organization South-East Asia region. Comparing findings from these two rounds provides trend data on smokeless tobacco (SLT) use for the first time.

METHODS

This study uses GYTS data from Bangladesh, Bhutan, India, Indonesia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand, and Timor-Leste during 2006-2013. GYTS is a nationally representative survey of 13-15-year-old students using a consistent and standard protocol. Current SLT use is defined as using any kind of SLT products, such as chewing betel quid or nonbetel quid or snuffing any other products orally or through the nasal route, during the 30 days preceding the survey. Prevalence and 95% confidence intervals were computed using SAS/SUDAAN software.

RESULTS

According to most recent GYTS data available in each country, the prevalence of current use of SLT among youth varied from 5.7% in Thailand to 23.2% in Bhutan; among boys, from 7.1% in Bangladesh to 27.2% in Bhutan; and among girls, from 3.7% in Bangladesh to 19.8% in Bhutan. Prevalence of SLT was reported significantly higher among boys than girls in Bhutan (boys 27.2%; girls 19.8%), India (boys 11.1%; girls 6.0%), Maldives (boys 9.2%; girls 2.9%), Myanmar (boys 15.2%; girls 4.0%), and Sri Lanka (boys 13.0%; girls 4.1%). Prevalence of current SLT use increased in Bhutan from 9.4% in 2009 to 23.2% in 2013, and in Nepal from 6.1% in 2007 to 16.2% in 2011.

CONCLUSION

The findings call for countries to implement corrective measures through strengthened policy and enforcement.

Evaluation of conditioning time and temperature on gelatinized starch and vitamin retention in a pelleted swine diet

Two key feed processing parameters, conditioning temperature and time, were altered to determine their effects on concentration of gelatinized starch and vitamin retention in a pelleted finishing swine diet. Diet formulation (corn–soybean meal based with 30% distillers dried grains with solubles) was held constant. Treatments were arranged in a 2 × 3 factorial design plus a control with 2 conditioning temperatures (77 vs. 88°C) and 3 conditioner retention times (15, 30, and 60 s). In addition, a mash diet not subjected to conditioning served as a control for a total of 7 treatments. Samples were collected after conditioning but before pelleting (hot mash), after pelleting but before cooling (hot pellet), and after pelleting and cooling (cold pellet) and analyzed for percentage total starch, percentage gelatinized starch, and riboflavin, niacin, and vitamin D3 concentrations. Total percentage starch was increased by greater conditioning temperature (P = 0.041) but not time (P > 0.10), whereas higher temperature and longer time both increased (P < 0.05) percentage gelatinized starch, with increasing time resulting in a linear increase in percentage starch gelatinization (P = 0.013). The interaction between conditioning temperature and time increased percentage gelatinized starch (P = 0.003) but not percentage total starch (P > 0.10). Sample location also affected both percentage total starch and gelatinized starch (P < 0.05), with the greatest increase in percentage gelatinized starch occurring between hot mash and hot pellet samples. As expected, the pelleting process increased percentage gelatinized starch (P = 0.035; 7.3 vs. 11.7% gelatinized starch for hot mash vs. hot pellet samples, respectively), but there was no difference in total starch concentrations (P > 0.10). Finally, neither conditioning temperature nor time affected riboflavin, niacin, or vitamin D3 concentrations (P > 0.10). In summary, both increasing conditioningtemperature and time effect percentage gelatinized starch, but not to the extent of forcing the diet through a pelleting die.

Evaluating lysine requirements of nursery pigs fed low protein diets with different sources of nonessential amino acids

The Lys requirement of nursery pigs may be dependent on the source of nonessential AA (NEAA) nitrogen or the source of Lys itself. However, little peer-reviewed data examines these phenomena. The objectives of these experiments were to determine if the Lys requirement of pigs is altered when 1) low protein diets are supplemented with different sources of NEAA nitrogen or 2) Lys is supplied as a crystalline source instead of intact protein such as soybean meal (SBM). Two 14-d experiments were conducted using 450 (Exp. 1) and 540 (Exp. 2) pigs (PIC C22/C29 × 337). There were 10 treatments in each experiment, each aligned as a 2 × 5 factorial. In Exp. 1, there were 2 sources of NEAA (l-Gln + l-Gly or l-Gly + l-Ala + l-Pro + l-His) and 5 levels of Lys (1.2, 1.3, 1.4, 1.5, and 1.6%). In Exp. 2, there were 2 sources of proteins providing additional Lys (l-Lys HCl or SBM) and the same 5 levels of Lys. Following weaning at 18 to 22 d of age, pigs were fed a common starter diet for 5 d postweaning followed by a 14-d treatment period. Pigs were weighed and feed disappearance determined on d 0, 7, and 14 of the experiment. Data were analyzed using the MIXED and NLIN procedures of SAS (SAS Inst., Cary, NC). In Exp. 1, increasing CP and Lys resulted in a quadratic increase (P < 0.05) in ADG and a linear improvement (P < 0.05) in G:F during the 14-d treatment period. Breakpoint regression analyses revealed that optimum ADG was obtained at 1.36% Lys, while optimum G:F was obtained at 1.45% Lys. The source of NEAA did not affect (P > 0.10) growth performance during the treatment period. In Exp. 2, both ADG and G:F increased linearly (P < 0.05) with increasing Lys. Optimal ADG was obtained at 1.47% Lys, but the breakpoint for optimum G:F was above tested levels. Source of Lys did not affect (P > 0.10) ADG, but pigs fed additional Lys from crystalline sources had improved (P < 0.05) G:F than those fed additional Lys from intact protein at 1.50% Lys; however, the analyzed Lys values at this level differ. Overall, these data show that the standardized ileal digestibility Lys requirement of pigs is not altered when low protein diets are supplemented with different sources of NEAA nitrogen. Feed efficiency appears to be maximized when additional Lys is supplied by l-Lys HCl instead of SBM, but more research is needed to confirm this phenomenon.

N-aryl piperazine metabotropic glutamate receptor 5 positive allosteric modulators possess efficacy in preclinical models of NMDA hypofunction and cognitive enhancement

Impaired transmission through glutamatergic circuits has been postulated to play a role in the underlying pathophysiology of schizophrenia. Furthermore, inhibition of the N-methyl-d-aspartate (NMDA) subtype of ionotropic glutamate receptors (NMDAR) induces a syndrome that recapitulates many of the symptoms observed in patients with schizophrenia. Selective activation of metabotropic glutamate receptor subtype 5 (mGlu5) may provide a novel therapeutic approach for treatment of symptoms associated with schizophrenia through facilitation of transmission through central glutamatergic circuits. Here, we describe the characterization of two novel N-aryl piperazine mGlu5 positive allosteric modulators (PAMs): 2-(4-(2-(benzyloxy)acetyl)piperazin-1-yl)benzonitrile (VU0364289) and 1-(4-(2,4-difluorophenyl)piperazin-1-yl)-2-((4-fluorobenzyl)oxy)ethanone (DPFE). VU0364289 and DPFE induced robust leftward shifts in the glutamate concentration-response curves for Ca(2+) mobilization and extracellular signal-regulated kinases 1 and 2 phosphorylation. Both PAMs displayed micromolar affinity for the common mGlu5 allosteric binding site and high selectivity for mGlu5. VU0364289 and DPFE possessed suitable pharmacokinetic properties for dosing in vivo and produced robust dose-related effects in reversing amphetamine-induced hyperlocomotion, a preclinical model predictive of antipsychotic-like activity. In addition, DPFE enhanced acquisition of contextual fear conditioning in rats and reversed behavioral deficits in a mouse model of NMDAR hypofunction. In contrast, DPFE had no effect on reversing apomorphine-induced disruptions of prepulse inhibition of the acoustic startle reflex. These mGlu5 PAMs also increased monoamine levels in the prefrontal cortex, enhanced performance in a hippocampal-mediated memory task, and elicited changes in electroencephalogram dynamics commensurate with procognitive effects. Collectively, these data support and extend the role for the development of novel mGlu5 PAMs for the treatment of psychosis and cognitive deficits observed in individuals with schizophrenia.

Potentiation of mGlu5 receptors with the novel enhancer, VU0360172, reduces spontaneous absence seizures in WAG/Rij rats

Absence epilepsy is generated by the cortico-thalamo-cortical network, which undergoes a finely tuned regulation by metabotropic glutamate (mGlu) receptors. We have shown previously that potentiation of mGlu1 receptors reduces spontaneous occurring spike and wave discharges (SWDs) in the WAG/Rij rat model of absence epilepsy, whereas activation of mGlu2/3 and mGlu4 receptors produces the opposite effect. Here, we have extended the study to mGlu5 receptors, which are known to be highly expressed within the cortico-thalamo-cortical network. We used presymptomatic and symptomatic WAG/Rij rats and aged-matched ACI rats. WAG/Rij rats showed a reduction in the mGlu5 receptor protein levels and in the mGlu5-receptor mediated stimulation of polyphosphoinositide hydrolysis in the ventrobasal thalamus, whereas the expression of mGlu5 receptors was increased in the somatosensory cortex. Interestingly, these changes preceded the onset of the epileptic phenotype, being already visible in pre-symptomatic WAG/Rij rats. SWDs in symptomatic WAG/Rij rats were not influenced by pharmacological blockade of mGlu5 receptors with MTEP (10 or 30 mg/kg, i.p.), but were significantly decreased by mGlu5 receptor potentiation with the novel enhancer, VU0360172 (3 or 10 mg/kg, s.c.), without affecting motor behaviour. The effect of VU0360172 was prevented by co-treatment with MTEP. These findings suggest that changes in mGlu5 receptors might lie at the core of the absence-seizure prone phenotype of WAG/Rij rats, and that mGlu5 receptor enhancers are potential candidates to the treatment of absence epilepsy. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.

Characterizing growth and carcass composition differences in pigs with varying weaning weights and postweaning performance

The unprecedented increase in litter size over the last decade has led to a perceived increase in the number of fallback pigs (Sus scrofa). However, there is little peer-reviewed data available regarding the biological differences between fallback pigs and their normal cohorts. Therefore, the objective of this experiment was to identify differences in the biology and physiology, and thus the growth and metabolism, between pigs with varying weaning weights (WW) and postweaning performance. To accomplish this objective, a total of 120 barrows (PIC C22/C29 × 337) were used in growth and comparative slaughter experiments. Pigs were selected from a population of 960 weanling pigs to represent the 10% lightest, median, and heaviest pigs at weaning (n = 40 pigs per WW category). Eight pigs from each WW category were harvested on d 5 postweaning as the initial slaughter group (ISG). The remaining 96 barrows were housed in individual crates, fed ad libitum quantities of a common diet during a 27-d growth study, and were harvested on d 33 or 34 postweaning. After the completion of the live animal component of the experiment, pigs within each WW category were further stratified into the slowest, median, or fastest 33% ADG categories. This resulted in a total of 9 treatments in a nested design. Fallback pigs were designated as those belonging to the slowest ADG category from either the lightest or median WW categories. Data were analyzed using the GLIMMIX procedure of SAS with the fixed effects of WW category and WW(ADG). Although feed intake was maximized (P < 0.0001) by WW(ADG) category, feed efficiency was not different (P = 0.30). When equalized per unit of BW, WW(ADG) category greatly affected (P < 0.02) eviscerated carcass, organ, and metabolic BW, but not (P = 0.28) empty BW. There were no differences (P > 0.12) in tissue nutrient concentrations, ratios, or energy content among pigs in the growth experiment. All tissue deposition rates, which were calculated as the difference between tissue nutrient concentrations of the growth experiment and initial slaughter groups, were maximized (P < 0.0002) by WW(ADG), even when equalized per unit of BW. In conclusion, WW and ADG affect tissue accretion rates, but not feed efficiency or carcass composition in nursery pigs.

Metabotropic glutamate receptors for new treatments in schizophrenia

Metabotropic glutamate receptors (mGluRs) represent exciting targets for the development of novel therapeutic agents for schizophrenia. Recent studies indicate that selective activation of specific mGluR subtypes may provide potential benefits for not only the positive symptoms, but also the negative symptoms and cognitive impairments observed in individuals with schizophrenia. Although optimization of traditional orthosteric agonists may still offer a feasible approach for the activation of mGluRs, important progress has been made in the discovery of novel subtype-selective allosteric ligands, including positive allosteric modulators (PAMs) of mGluR2 and mGluR5. These allosteric mGluR ligands have improved properties for clinical development and have served as key preclinical tools for a more in-depth understanding of the potential roles of these different mGluR subtypes for the treatment of schizophrenia.

Factors affecting storage stability of various commercial phytase sources

A 360-d study was performed to evaluate the effects of different environmental conditions on storage stability of exogenous phytases. Coated and uncoated products from 3 phytase sources [Ronozyme P (DSM Nutritional Products, Basel, Switzerland), OptiPhos (Phytex LLC, Sheridan, IN), and Phyzyme (Danisco Animal Nutrition, Marlborough, UK)] were stored as pure forms, in a vitamin premix, or in a vitamin and trace mineral (VTM) premix. Pure products were stored at -18, 5, 23, and 37°C (75% humidity). Premixes were stored at 23 and 37°C. Sampling was performed on d 0, 30, 60, 90, 120, 180, 270, and 360. Sampling of the pure products stored at -18 (lack of sample) and 5°C (because of mold growth) was discontinued after d 120. Stability was reported as the residual phytase activity (% of initial) at each sampling point. For the stability of the pure forms, all interactive and main effects of the phytase product, coating, time, and storage temperature were significant (P < 0.01), except for the time × coating interaction. When stored at 23°C or less, pure phytases retained at least 91, 85, 78, and 71% of their initial phytase activity at 30, 60, 90, and 120 d of storage, respectively. However, storing pure products at 37°C reduced (P < 0.01) phytase stability, with OptiPhos retaining the most (P < 0.01) activity. Coating mitigated (P < 0.01) the negative effects of high storage temperature for Ronozyme and OptiPhos (from d 90 onward), but not for Phyzyme. For the stability of phytase in different forms of storage, all interactive and main effects of phytase product, form, coating, time, and temperature of storage were significant (P < 0.01). When stored at room temperature (23°C), retained phytase activities for most the phytase sources were more than 85, 73, and 60% of the initial activity up to 180 d when stored as pure products, vitamin premixes, or VTM premixes, respectively. When stored at 37°C, pure phytase products had greater (P < 0.01) retention of initial phytase activity than when phytases were mixed with the vitamin or VTM premixes. Coated phytases stored in any form had greater (P < 0.01) activity retention than the uncoated phytases at all sampling periods. Results indicate that storage stability of commercially available phytases is affected by duration of storage, temperature, product form, coating, and phytase source. Pure products held at 23°C or less were the most stable. In premixes, longer storage times and higher temperatures reduced phytase activity, but coating mitigated some of these negative effects.

Efficacy of different commercial phytase enzymes and development of an available phosphorus release curve for Escherichia coli-derived phytases in nursery pigs

In 2 experiments, a total of 184 pigs (PIC, initial BW of 10.3 and 9.7 kg for Exp. 1 and 2, respectively) were used to develop an available P (aP) release curve for commercially available Escherichia coli-derived phytases. In both experiments, pigs were fed a corn-soybean meal basal diet (0.06% aP) and 2 diets with added inorganic P (iP) from monocalcium phosphate (Exp. 1: 0.075 and 0.15% aP; Exp. 2: 0.07 and 0.14% aP) to develop a standard curve. In Exp. 1, 100, 175, 250, or 500 phytase units (FTU)/kg of OptiPhos 2000 or 200, 350, 500, or 1,000 FTU/kg of Phyzyme XP were added to the basal diet. In Exp. 2, 250, 500, 750, or 1,000 FTU/kg of OptiPhos 2000; 500, 1,000, or 1,500 FTU/kg of Phyzyme XP; or 1,850 or 3,700 FTU/kg of Ronozyme P were added to the basal diet. One FTU was defined as the amount of enzyme required to release 1 µmol of iP per minute from sodium phytate at 37°C. For all phytase products, the manufacturer-guaranteed phytase activities were used in diet formulation. All diets were analyzed for phytase activity using both the Phytex and AOAC methods. Pigs were blocked by sex and BW and allotted to individual pens with 8 pens per treatment. Pigs were killed on d 21, and fibulas were collected and analyzed for bone ash. In both experiments, increasing iP improved (linear, P < 0.01) G:F and percentage bone ash. Pigs fed increasing OptiPhos had improved (Exp. 1: linear, P < 0.001; Exp. 2: quadratic, P < 0.001) percentage bone ash, as did pigs fed increasing Phyzyme XP (linear, P < 0.001). In Exp. 2, increasing Ronozyme P improved (quadratic, P < 0.01) percentage bone ash. Using analyzed values from the AOAC method and percentage bone ash as the response variable, an aP release curve was developed for up to 1,000 FTU/kg of E. coli-derived phytases (OptiPhos 2000 and Phyzyme XP) in P-deficient diets. The prediction equation was Y = -0.000000125X(2) + 0.000236X + 0.016, where Y = aP release (%) and X = analyzed phytase (FTU/kg) in the diet.

Effects of fermented soybean meal and specialty animal protein sources on nursery pig performance

In 2 experiments, 602 pigs were used to evaluate the effects of fish meal, fermented soybean meal, or dried porcine solubles on phase 2 nursery pig performance. In Exp. 1, nursery pigs (n = 252; PIC TR4 x 1050; 6.8 kg initial BW and 7 d after weaning) were fed: 1) a control diet containing no specialty protein sources and the control diet with 2) 5% fish meal, 3) 3.5% dried porcine solubles, 4) 6.0% fermented soybean meal, 5) a combination of 1.75% fermented soybean meal and 1.75% dried porcine solubles, or 6) a combination of 3.0% fermented soybean meal and 2.5% fish meal. There were 7 replications with 6 pigs per pen. Experimental diets were fed for 14 d, and then all pigs were fed a common diet without specialty protein sources for 14 d. From d 0 to 14, pigs fed dried porcine solubles alone or with fermented soybean meal had improved (P < 0.05) ADG and G:F compared with pigs fed all other diets. Overall (d 0 to 28), pigs fed dried porcine solubles had improved (P = 0.01) ADG (421 vs. 383 g) and G:F (0.77 vs. 0.73) compared with pigs fed the control diet and had improved (P = 0.03) G:F (0.77 vs. 0.74) compared with pigs fed the combination of fermented soybean meal and fish meal. In Exp. 2, nursery pigs (n = 350; PIC C22 x 1050; 6.1 kg initial BW and 7 d after weaning) were fed 1) a control diet containing no specialty protein sources and the control diet with 2) 3% fish meal, 3) 6% fish meal, 4) 3.75% fermented soybean meal, 5) 7.50% fermented soybean meal, 6) a combination of 1.88% fermented soybean meal and 1.88% dried porcine solubles, or 7) a combination of 3.75% fermented soybean meal and 3.75% dried porcine solubles. There were 10 replications with 5 pigs per pen. Experimental diets were fed from d 0 to 14, and then all pigs were fed a common diet without specialty protein sources for 21 d. From d 0 to 14, pigs fed increasing fish meal had increased (quadratic, P = 0.05) ADFI. Pigs fed increasing fermented soybean meal had improved (quadratic, P = 0.01) G:F. Pigs fed the combination of fermented soybean meal and dried porcine solubles had improved (P < 0.05) ADG and G:F compared with pigs fed diets containing fish meal and had improved (P < 0.05) ADG and ADFI compared with pigs fed diets containing fermented soybean meal. Overall (d 0 to 35), pigs fed diets with increasing amounts of fermented soybean meal had improved (quadratic, P = 0.03) G:F. Feeding nursery pigs diets containing dried porcine solubles, either alone or in combination with fermented soybean meal, can improve growth performance compared with those fed high concentrations of soybean meal or fish meal.

Selective potentiation of the metabotropic glutamate receptor subtype 2 blocks phencyclidine-induced hyperlocomotion and brain activation

Previous preclinical and clinical studies have demonstrated the efficacy of group II metabotropic glutamate receptor (mGluR) agonists as potential antipsychotics. Recent studies utilizing mGluR2-, mGluR3-, and double knockout mice support that the antipsychotic effects of those compounds are mediated by mGluR2. Indeed, biphenyl indanone-A (BINA), an allosteric potentiator of mGluR2, is effective in experimental models of psychosis, blocking phencyclidine (PCP)-induced hyperlocomotion and prepulse inhibition deficits in mice. In this study, we administered the NMDA receptor antagonist PCP (5.6 mg/kg i.p.) to rats, an established animal model predictive of schizophrenia. Here, we show that BINA (32 mg/kg i.p.) attenuated PCP-induced locomotor activity in rats. Using behaviorally relevant doses of BINA and PCP, we performed pharmacological magnetic resonance imaging (phMRI) to assess the specific brain regions that underlie the psychotomimetic effects of PCP, and examined how BINA modulated the PCP-induced functional changes in vivo. In anesthetized rats, acute administration of PCP produced robust, sustained blood oxygenation level-dependent (BOLD) activation in specific cortical, limbic, thalamic, and striatal regions. Pretreatment with BINA suppressed the amplitude of the BOLD response to PCP in the prefrontal cortex, caudaute-putamen, nucleus accumbens, and mediodorsal thalamus. Our results show key brain structures underlying PCP-induced behaviors in a preclinical model of schizophrenia, and, importantly, its reversal by potentiation of mGluR2 by BINA, revealing specific brain regions functionally involved in its pharmacological action. Finally, our findings bolster the growing body of evidence that mGluR2 is a viable target for the treatment of schizophrenia.

Efficacy of commercial enzymes in diets containing various concentrations and sources of dried distillers grains with solubles for nursery pigs

In 2 experiments, 530 pigs were used to evaluate the effects of adding commercial enzymes to diets containing dried distillers grains with solubles (DDGS) on pig growth performance. In the first experiment, 180 pigs (9.0 kg initial BW) were fed a corn-soybean meal-based control diet, a diet containing 30% corn DDGS, or the 30% DDGS diet with 0.05% of enzyme A, B, or C. There were 6 pigs per pen and 6 pens per treatment. Overall (d 0 to 27), neither DDGS nor enzyme addition increased ADG and G:F. Pigs fed enzyme B had decreased (P < 0.05) ADG as a result of a tendency (P <or= 0.10) for decreased ADFI compared with control pigs or pigs fed DDGS without added enzyme. In Exp. 2, 350 pigs (11.0 kg initial BW) were fed 1 of 10 dietary treatments. Pigs were fed a control corn-soybean meal-based diet or the control diet containing 15 or 30% DDGS from 3 sources (corn, sorghum 1, or sorghum 2). Diets containing 30% DDGS were fed with or without the same enzyme (enzyme A) as Exp. 1. There were 5 pigs per pen and 7 pens per treatment. Overall (d 7 to 28), there were no (P > 0.10) enzyme x DDGS source interactions observed. Corn DDGS did not influence (P > 0.10) ADG, ADFI, or G:F. Sorghum DDGS reduced (P = 0.003) G:F, with no difference (P > 0.10) between sorghum DDGS sources. Adding the commercial enzyme to the 30% DDGS diets did not improve performance. In summary, feeding diets with sorghum DDGS resulted in poorer G:F with no change in ADG compared with feeding the control diet or diets containing corn DDGS. Adding the enzymes used in this study to corn-soybean meal-based diets containing 30% DDGS did not improve growth performance.

Quantitative characterization of the corticospinal tract at 3T

BACKGROUND AND PURPOSE

White matter tract-specific imaging will probably become a major component of clinical neuroradiology. Fiber tracking with diffusion tensor imaging (DTI) is widely used, but variability is substantial. This article reports the ranges of MR imaging appearance and right-left asymmetry of healthy corticospinal tracts (CST) reconstructed with DTI.

METHODS

For 20 healthy volunteers, whole-brain DTI data were coregistered with maps of absolute T1 and T2 relaxation times and magnetization transfer ratio (MTR), all acquired at 3T. For each individual, the 2 reconstructed CSTs and their asymmetry were analyzed with respect to the number of fibers reconstructed; tract volume; and individual MR imaging parameters restricted to the tracts. Interscan variability was estimated by repeat imaging of 8 individuals.

RESULTS

Reconstructed fiber number and tract volume are highly variable, rendering them insensitive to abnormalities in disease. Individual tract-restricted MR imaging parameters are more constrained, and their population averages and normal ranges are reported. The average population asymmetry is generally zero; therefore, normal ranges for an index of asymmetry are reported. By way of example, CST-restricted MR imaging parameters and their asymmetries are shown to be abnormal in an individual with multiple sclerosis who had a lesion affecting the CST.

CONCLUSIONS

The results constitute a normative dataset for the following imaging parameters of the CST: T1, T2, MTR, fractional anisotropy, mean diffusivity, transverse diffusivity, and the 3 diffusion tensor eigenvalues. These data can be used to identify, characterize, and establish the significance of changes in diseases that affect the CST.

Abdominal fat pad aspiration biopsy for tissue confirmation of systemic amyloidosis: specificity, positive predictive value, and diagnostic pitfalls

Abdominal fat pad fine-needle aspiration biopsy (FNAB) is considered the method of choice for confirmation of systemic amyloidosis. Due to our impression that positive results are rare in our FNA service, we retrospectively analyzed our results. Forty-five samples collected from 45 patients over 3 yr were reviewed. Of the 7 patients with positive Congo red-stained FNAB specimens, all 7 (100%) had documented amyloidosis. Of the 33 patients with negative Congo red fat samples, 28 (85%) were disease-free. Of the 5 patients with inadequate samples, 2 (40%) were later diagnosed with disease. We demonstrate excellent specificity (100%). The positive predictive value, documented in only a few previous studies, is likewise excellent (100%). Sensitivity is low (58%) and inadequacy is high (11%). Improvement in technique, such as concurrent cell block preparation, may help avoid inadequate specimens. Difficulties in confirming amyloidosis also include interpretation of the Congo red stain (pale-stained amyloid fibrils and collagen birefringence).

Soliton internal mode bifurcations: pure power law?

The bifurcation of internal solitary wave modes from the essential spectrum has been one of the most exciting recent developments in the study of soliton dynamics. To date, it was believed that the bifurcation of such modes due to discretization has a strict power law dependence on the lattice discreteness parameter. In this work we prove that this dependence actually possesses relevant exponentially small terms which distinguish between different solutions for the discrete models. The theoretical result is established by using a discrete version of the Evans function. The predictions presented herein compare very favorably with the numerical study of the linear eigenvalue problem, and offer explanations of computational effects not possible on the basis of previous theoretical studies.

Stability of neuronal pulses composed of concatenated unstable kinks

We demonstrate that a traveling pulse solution, emerging from the concatenation of two unstable kinks, can be stable. By means of stability analysis and numerical simulations, we show the stability of neuronal pulses (action potentials) with increasing refractory periods, which decompose into two (radiationally) unstable kinks in the limit. These action potentials are solutions of an ultrarefractory version of the FitzHugh-Nagumo system.

Stiffness of simulated radial neck fractures fixed with 4 different devices

We performed a structural investigation of several fixation devices for radial head and neck fixation. Fourteen pairs of fresh-frozen human elbows were used to simulate unstable radial neck fractures fixed with each of the following plates: 2.0-mm T-plate, 2.0-mm blade plate, 2.7-mm T-plate, and 2.7-mm T-plate modified with a fixed-angle blade. The plate constructs were axially loaded in compression with a materials testing machine, and stiffness was calculated from a load-deformation curve. Through use of paired comparisons, the average stiffness of the modified 2.7-mm plate was found to be significantly greater than that of either 2.0-mm plate, whereas a trend was observed for increased stiffness of the modified 2.7-mm T-plate in comparison with the standard 2.7-mm T-plate. The results indicate that two important variables affecting construct stiffness are plate thickness and incorporation of a fixed-angle blade. Given these findings, the addition of a fixed blade to the 2.7-mm plate may improve the stability of fixation of comminuted radial neck fractures.

Ground states of dispersion-managed nonlinear Schrodinger equation

An exact pulse for the parametrically forced nonlinear Schrodinger equation (NLS) is isolated. The equation governs wave envelope propagation in dispersion-managed fiber lines with positive residual dispersion. The pulse is obtained as a ground state of an averaged variational principle associated with the equation governing pulse dynamics. The solutions of the averaged and original equations are shown to stay close for a sufficiently long time. A properly adjusted pulse will therefore exhibit nearly periodic behavior in the time interval of validity of the averaging procedure. Furthermore, we show that periodic variation of dispersion can stabilize spatial solitons in a Kerr medium and one-dimensional solitons in the NLS with quintic nonlinearity. The results are confirmed by numerical simulations.

Muscarinic cholinergic modulation of prepulse inhibition of the acoustic startle reflex

The purpose of the present study was to determine the effects of muscarinic cholinergic receptor antagonists and agonists on prepulse inhibition (PPI) of the acoustic startle reflex in rats. The muscarinic receptor antagonist scopolamine (0.03-1.0 mg/kg) produced a significant dose-dependent decrease in PPI without affecting startle amplitude. In contrast, N-methyl scopolamine, the quaternary analog of scopolamine, had no effect on PPI, indicating that scopolamine disrupted PPI through a central cholinergic mechanism. Two other muscarinic receptor antagonists, trihexyphenidyl (0.3-10 mg/kg) and benztropine (0.03-10 mg/kg), produced significant decreases in PPI similar to scopolamine. On the other hand, the muscarinic receptor antagonists dicyclomine (0.03-10 mg/kg) and biperiden (0.03-10 mg/kg) had no effect on PPI but significantly decreased startle amplitude. Mecamylamine (0.1-10 mg/kg), a nicotinic receptor antagonist, also had no effect on PPI. Administered alone, the muscarinic receptor agonists pilocarpine (0. 03-10 mg/kg), oxotremorine (0.01-0.3 mg/kg), RS-86 (0.1-3.0 mg/kg), and arecoline (0.3-10 mg/kg), as well as the cholinesterase inhibitors physostigmine (0.01-0.3 mg/kg) and tacrine (0.03-10 mg/kg), had no effect on PPI, but each produced significant decreases in startle amplitude at the highest doses tested. In addition, the disruption of PPI by scopolamine was reversed in a dose-dependent manner by the muscarinic receptor agonist oxotremorine. The present findings demonstrate that the muscarinic cholinergic system plays an important role in the normal mechanisms of PPI.

Instability of multiple pulses in coupled nonlinear Schrodinger equations

An analytical technique for constructing multiple pulses is presented in this article; with it we uncover a homoclinic bifurcation through which multihumped solitary waves can be generated in systems of coupled nonlinear Schrodinger equations. A method is then developed to determine the (in)stability of multiple pulses produced by this mechanism. The analysis is applied to two models that describe optical phenomena in dispersive quadratic and Kerr media, respectively. It sheds considerable light upon the characteristics that predispose multiple pulses arising in this class of systems to be unstable.

Effects of scopolamine in comparison with apomorphine and phencyclidine on prepulse inhibition in rats

The potential involvement of the muscarinic cholinergic system in the underlying mechanisms of prepulse inhibition of the acoustic startle reflex was evaluated in male Sprague-Dawley rats under conditions of varying dose, prepulse intensity, and interstimulus interval. The effects of scopolamine on prepulse inhibition were also directly compared with the effects observed using apomorphine and phencyclidine under the same test parameters. Scopolamine (0. 03-1.0 mg/kg) produced a significant dose-dependent decrease in prepulse inhibition, but had no effect on startle amplitude over the dose range tested. Apomorphine (0.03-1.0 mg/kg) and phencyclidine (0. 1-5.6 mg/kg) produced significant dose-dependent decreases in prepulse inhibition and changes in startle amplitude. The scopolamine-induced decrease in prepulse inhibition varied with prepulse intensity in that the changes produced by scopolamine became smaller in magnitude as the prepulse intensity was increased from 9 to 30 dB above background. On the other hand, apomorphine and phencyclidine decreased prepulse inhibition to approximately the same magnitude across all prepulse intensities tested. The observed decreases in prepulse inhibition produced by scopolamine, apomorphine, and phencyclidine were also dependent on interstimulus interval duration. Scopolamine produced marked decreases in prepulse inhibition at the 100- and 300-ms interstimulus interval durations, but had little or no effect on prepulse inhibition at the 30- and 1000-ms interstimulus interval durations. In contrast, apomorphine decreased prepulse inhibition across all interstimulus interval durations while phencyclidine decreased prepulse inhibition across the 30- to 300-ms interstimulus interval durations. The present findings support the hypothesis that the muscarinic cholinergic system, like the dopaminergic and glutamatergic systems, is directly involved in the mechanisms of prepulse inhibition. However, these three neurotransmitter systems appear to modulate different aspects of prepulse inhibition.

Gerstmann-Sträussler-Scheinker disease with mutation at codon 102 and methionine at codon 129 of PRNP in previously unreported patients

We present two patients with Gerstmann-Sträussler-Scheinker disease (GSS), one from a previously undescribed kindred and one from the Canadian branch of a previously reported British kindred. In both patients, GSS is caused by a substitution of thymine for cytosine at codon 102 of the prion protein gene (PRNP). In each patient, we confirmed the clinical diagnosis by neuropathologic examination. The mutation, causing a substitution of leucine for proline at residue 102 (P102L) of the prion protein, has been previously reported in at least 30 other families. In the patients described here, the mutation was in coupling with methionine at PRNP codon 129.

Presenting signs and symptoms of nasopharyngeal carcinoma

Pain in the head and neck may be due to multiple causes and difficult to localize. A definitive diagnosis can be difficult to make. The literature reports several cases of nasopharyngeal carcinoma presenting as temporomandibular disorders (TMD). The records of 52 patients with a diagnosis of nasopharyngeal carcinoma were reviewed to determine the frequency of symptoms that may be similar to TMD. In 13.5% of the patients common TMD signs and symptoms were present, such as clicking in the joint, pain while chewing, and limited opening. Of the patients reviewed, 44.2% described the location of their pain as headache, earache, or as jaw, midface, or neck pain. The most common description of pain was aching, dull, or pressing. Symptoms identified that may assist in differentiation of nasopharyngeal carcinoma from TMD include nosebleed, nasal stuffiness, altered hearing, and cervical lymph node enlargement. A patient with carcinoma of the nasopharynx may have symptoms that must be differentiated from TMD.

The efficacy of gallium scintigraphy in detecting malignant soft tissue neoplasms

A prospective study was conducted on 55 consecutive patients to evaluate the efficacy of gallium scintigraphy in detecting malignancy in any soft tissue mass. It was determined that gallium scintigraphy could detect malignancy with a sensitivity of 96% and a specificity of 87%. Large and small sarcomas, irrespective of their fascial location, were identifiable by gallium imaging. Occult, nonpulmonary sites of disseminated disease were detected in 13%. Gallium scintigraphy proved to be a reliable predictor of malignancy for all soft tissue masses, but because of its cost, it must be used judiciously.

A developmental approach to preschool vision screening

A developmental approach to preschool vision screening is described. The choice of acuity testing material in this test is determined by the child's capabilities, assessed prior to acuity testing. When compared with the Society for Prevention of Blindness test, this approach yields approximately half the number of untestables. Further, the acuity data from the two screening tests are quite similar, and both agree well with data from an additional screening by a pediatric ophthalmologist. Screening of preschool children usually requires a number of compromises in methods felt to be ideal for adults. Sacrifices in cost (i.e., additional personnel to assist the tester), additional effort (i.e., prior training of the children), or precision of acuity measures (i.e., cruder picture type targets for all children and use of isolated targets) are typically made to assure testability. These problems have been minimized by the Experimental method. Because of its low untestability rate and its apparently valid acuity data, this developmental vision screening test can be recommended as a cost effective approach to preschool vision screening. Previous research has shown that ratings of a child's behavior during this developmentally oriented vision screening test predict results of diagnostic cognitive tests as accurately as extensive tests designed exclusively for developmental screening. This test is then extremely cost effective when used for comprehensive preschool screening.