bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability of the biceps brachii M-wave
Authors: Calder Kristina M , Hall Lesley-Ann , Lester Steve M , Inglis J Greig , Gabriel David A
Published: December 2005

Background

The peak-to-peak (P-P) amplitude of the maximum M-wave and the area of the negative phase of the curve are important measures that serve as methodological controls in H-reflex studies, motor unit number estimation (MUNE) procedures, and normalization factors for voluntary electromyographic (EMG) activity. These methodologies assume, with little evidence, that M-wave variability is minimal. This study therefore examined the intraclass reliability of these measures for the biceps brachii.

Methods

Twenty-two healthy adults (4 males and 18 females) participated in 5 separate days of electrical stimulation of the musculocutaneous nerve supplying the biceps brachii muscle. A total of 10 stimulations were recorded on each of the 5 test sessions: a total of fifty trials were used for analysis. A two-factor repeated measures analysis of variance (ANOVA) evaluated the stability of the group means across test sessions. The consistency of scores within individuals was determined by calculating the intraclass correlation coefficient (ICC). The variance ratio (VR) was then used to assess the reproducibility of the shape of the maximum M-wave within individual subjects.

Results

The P-P amplitude means ranged from 12.62 ± 4.33 mV to 13.45 ± 4.07 mV across test sessions. The group means were highly stable. ICC analysis also revealed that the scores were very consistent (ICC = 0.98). The group means for the area of the negative phase of the maximum M-wave were also stable (117 to 126 mV·ms). The ICC analysis also indicated a high degree of consistency (ICC = 0.96). The VR for the sample was 0.244 ± 0.169, which suggests that the biceps brachii maximum M-wave shape was in general very reproducible for each subject.

Conclusion

The results support the use of P-P amplitude of the maximum M-wave as a methodological control in H-reflex studies, and as a normalization factor for voluntary EMG. The area of the negative phase of the maximum M-wave is both stable and consistent, and the shape of the entire waveform is highly reproducible and may be used for MUNE procedures.
Importance of disulphide bonds for vaccinia virus L1R protein function
Authors: Blouch Robert E , Byrd Chelsea M , Hruby Dennis E
Published: December 2005

L1R, a myristylated late gene product of vaccinia virus, is essential for formation of infectious intracellular mature virions (IMV). In its absence, only viral particles arrested at an immature stage are detected and no infectious progeny virus is produced. Previous studies have shown that the L1R protein is exclusively associated with the IMV membrane and that myristylation is required for correct targeting. The L1R protein contains six cysteine amino acid residues that have all been shown to participate in intramolecular disulphide bonds. However, it was not clear what role, if any, the disulfide bonds play in the membrane topology of the L1R protein. To address this question, a comprehensive library of L1R mutants in which the cysteine residues have been mutated to serine (either individually or in combination) were tested for their ability to rescue a L1R conditional lethal mutant virus under non-permissive conditions. Much to our surprise, we determined that C57 was not essential for production of infectious IMV. These results suggest that protein disulphide isomerases may be involved in reorganization of disulfide bonds within the L1R protein.
Response inhibition deficits in externalizing child psychiatric disorders: An ERP-study with the Stop-task
Authors: Albrecht Björn , Banaschewski Tobias , Brandeis Daniel , Heinrich Hartmut , Rothenberger Aribert
Published: December 2005

Background

Evidence from behavioural studies suggests that impaired motor response inhibition may be common to several externalizing child psychiatric disorders, although it has been proposed to be the core-deficit in AD/HD. Since similar overt behaviour may be accompanied by different covert brain activity, the aim of this study was to investigate both brain-electric-activity and performance measures in three groups of children with externalizing child psychiatric disorders and a group of normal controls.

Methods

A Stop-task was used to measure specific aspects of response inhibition in 10 children with attention-deficit hyperactivity disorder (AD/HD), 8 children with oppositional defiant disorder/conduct disorder (ODD/CD), 11 children with comorbid AD/HD+ODD/CD and 11 normal controls. All children were between 8 and 14 years old. Event-related potentials and behavioural responses were recorded. An initial go-signal related microstate, a subsequent Stop-signal related N200, and performance measures were analyzed using ANCOVA with age as covariate.

Results

Groups did not differ in accuracy or reaction time to the Go-stimuli. However, all clinical groups displayed reduced map strength in a microstate related to initial processing of the Go-stimulus compared to normal controls, whereas topography did not differ. Concerning motor response inhibition, the AD/HD-only and the ODD/CD-only groups displayed slower Stop-signal reaction times (SSRT) and Stop-failure reaction time compared to normal controls. In children with comorbid AD/HD+ODD/CD, Stop-failure reaction-time was longer than in controls, but their SSRT was not slowed. Moreover, SSRT in AD/HD+ODD/CD was faster than in AD/HD-only or ODD/CD-only. The AD/HD-only and ODD/CD-only groups displayed reduced Stop-N200 mean amplitude over right-frontal electrodes. This effect reached only a trend for comorbid AD/HD+ODD/CD.

Conclusion

Following similar attenuations in initial processing of the Go-signal in all clinical groups compared to controls, distinct Stop-signal related deficits became evident in the clinical groups. Both children with AD/HD and ODD/CD showed deficits in behavioural response-inhibition accompanied by decreased central conflict signalling or inhibition processes. Neither behavioural nor neural markers of inhibitory deficits as found in AD/HD-only and ODD/CD-only were additive. Instead, children with comorbid AD/HD+ODD/CD showed similar or even less prominent inhibition deficits than the other clinical groups. Hence, the AD/HD+ODD/CD-group may represent a separate clinical entity.
In adult onset myositis, the presence of interstitial lung disease and myositis specific/associated antibodies are governed by HLA class II haplotype, rather than by myositis subtype
Authors: Chinoy Hector , Salway Fiona , Fertig Noreen , Shephard Neil , Tait Brian D , Thomson Wendy , Isenberg David A , Oddis Chester V , Silman Alan J , Ollier William ER , Cooper Robert G ,   the UK Adult Onset Myositis Immunogenetic Collaboration (AOMIC)
Published: December 2005

The aim of this study was to investigate HLA class II associations in polymyositis (PM) and dermatomyositis (DM), and to determine how these associations influence clinical and serological differences. DNA samples were obtained from 225 UK Caucasian idiopathic inflammatory myopathy patients (PM = 117, DM = 108) and compared with 537 randomly selected UK Caucasian controls. All cases had also been assessed for the presence of related malignancy and interstitial lung disease (ILD), and a number of myositis-specific/myositis-associated antibodies (MSAs/MAAs). Subjects were genotyped for HLA-DRB1, DQA1 and DQB1. HLA-DRB1*03, DQA1*05 and DQB1*02 were associated with an increased risk for both PM and DM. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype demonstrated strong association with ILD, irrespective of myositis subtype or presence of anti-aminoacyl-transfer RNA synthetase antibodies. The HLA-DRB1*07-DQA1*02-DQB1*02 haplotype was associated with risk for anti-Mi-2 antibodies, and discriminated PM from DM (odds ratio 0.3, 95% confidence interval 0.1–0.6), even in anti-Mi-2 negative patients. Other MSA/MAAs showed specific associations with other HLA class II haplotypes, irrespective of myositis subtype. There were no genotype, haplotype or serological associations with malignancy. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype associations appear to not only govern disease susceptibility in Caucasian PM/DM patients, but also phenotypic features common to PM/DM. Though strongly associated with anti-Mi-2 antibodies, the HLA-DRB1*07-DQA1*02-DQB1*02 haplotype shows differential associations with PM/DM disease susceptibility. In conclusion, these findings support the notion that myositis patients with differing myositis serology have different immunogenetic profiles, and that these profiles may define specific myositis subtypes.
A study on the investigation of cadmium chloride genotoxicity in rat bone marrow using micronucleus test and chromosome aberration analysis
Authors: Çelik Ayla , Çömelekoğlu Ülkü , Yalin Serap
Published: December 2005

In this study, we investigated the genotoxic and cytotoxic potential of cadmium chloride (CdCl2)in Wistar rat tibia bone marrow cells, using the structural chromosomal aberration (SCA) and micronucleus (MN) test systems. CdCl2 was administered to adult female rats as repeated i.p. doses of 0.5 mg/kg b.w. for 18 week (four months) at 48 h intervals. Mitomycin C (MMC) was used as a positive control (2 mg/kg b.w.). This study shows that cadmium chloride treatment significantly induced the frequency of micronucleus in polychromatic erythrocytes in tibia bone marrow. This increase in micronucleus frequency shows that cadmium has a genotoxic effect on bone marrow at this level. Also, in order to determine cytotoxicity in bone marrow, the ratio of polychromatic erythrocytes to normochromatic erythrocytes was calculated in bone marrow. The results of this study indicate that CdCl2 decreased this ratio. The decrease of this ratio in bone marrow shows CdCl2 may lead to cytotoxicity. We have reported that 0.5 mg/kg-level chronic exposure to cadmium (Cd) has an injurious effect on bone marrow. Our findings indicate that CdCl2 has a cytotoxic and genotoxic effect on rat bone marrow at chronic exposure.
An experimental study of social attraction and spacing between the sexes in sheep
Authors: Michelena Pablo , Henric Karine , Angibault Jean-Marc , Gautrais Jacques , Lapeyronie Paul , Porter Richard H. , Deneubourg Jean-Louis , Bon Richard
Published: December 2005

Most ungulates are gregarious species and outside the mating season are typically observed in single-sex groups. However little is known about the mechanisms underlying social segregation between sexes. We investigated the effect of conspecific attraction on individual spacing between unrestrained merino sheep Ovis aries and confined conspecifics. We considered differences between males and females and whether attractiveness of the confined conspecifics depends on their sex. A series of binary choice experiments was conducted in a large outdoor arena, located in pastures. One or two stimulus animals were placed in small individual cages (1.5 m×1 m) on opposite sides of the arena. Sheep were tested with one fixed peer of the same or opposite sex vs an empty cage, and with two fixed peers of either the same sex as themselves, or one male and one female. Sheep in a control condition were exposed to two empty cages. In all of the test conditions, confined sheep were highly attractive. Males were more attracted by single stimulus peers of the same than the opposite sex, whereas females did not display such a preference. Sheep confronted with two restrained conspecifics tended to remain between the stimuli. This also occurred when the stimuli were of opposite sex, although the males tended to be located nearer the same-sex peer. Our findings can explain the strong aggregative behaviour of merino sheep, but also the social segregation previously observed in a mixed-sex group through higher attraction for same-sex than opposite-sex peers in males.
K+-independent initiation of motility in chum salmon sperm treated with an organic alcohol, glycerol
Authors: Morita M. , Fujinoki M. , Okuno M.
Published: December 2005

Sperm of salmonid fishes are quiescent in the presence of millimolar concentrations of extracellular K+, but motility initiation occurs when sperm are suspended in K+-free medium. In this study, glycerol(CH2OHCHOHCH2OH) treatment of intact sperm in the presence of K+ induced the initiation of motility even though a large amount of K+ was present. Another organic alcohol, erythritol(CH2OH(CHOH)2CH2OH), had a similar effect,but ethylene glycol (CH2OHCH2OH) did not initiate sperm motility. Furthermore, this glycerol-treated sperm showed motility without subsequent addition of ATP and cAMP. CCCP, an uncoupler of the mitochondrial electron-transport chain involved in ATP synthesis, suppressed motility of glycerol-treated sperm, suggesting that ATP synthesis is required for dynein to slide microtubules in glycerol-treated sperm. The amount of intracellular cAMP ([cAMP]i) in glycerol-treated sperm did not increase on motility activation, but a protein kinase A (PKA) inhibitor, H-89, inhibited glycerol-treated sperm motility. In addition, phosphorylation of protein associated with motility initiation also occurred in glycerol-treated sperm,suggesting that the glycerol treatment induces activation of PKA without an increase in [cAMP]i. Taken together, it can be concluded that organic alcohol, glycerol and erythritol induce phosphorylation for motility initiation, bypassing the increase in [cAMP]i as a result of a decrease in extracellular K+ concentration.
Locomotor function of the dorsal fin in rainbow trout: kinematic patterns and hydrodynamic forces
Authors: Drucker Eliot G. , Lauder George V.
Published: December 2005

In this study, we examine the kinematics and hydrodynamics of the soft dorsal fin in a representative basal teleost, the rainbow trout(Oncorhynchus mykiss), during steady rectilinear locomotion at 0.5–2.0 body lengths (L) s–1 and during maneuvering. During steady swimming, dorsal fin height and sweep amplitude decrease with increasing speed. The dorsal fin wake, as viewed within a horizontal plane, consists of paired vortices on each side of the body (0.5 L s–1) or nearly linearly arrayed vortex centers above the body (1.0 L s–1) with central jet flows directed predominately laterally (lateral:thrust force ratio=5–6). At 2.0 L s–1, the dorsal fin is no longer recruited to add momentum to the wake. This pattern of decreasing involvement of the trout dorsal fin in thrust production with increasing speed contrasts with the results of our previous study of the soft dorsal fin of sunfish(Lepomis), which is hydrodynamically inactive at low speed and sheds a propulsive vortex wake at higher speed. Yawing maneuvers by trout involve unilateral production of a single vortex ring by the dorsal fin with a strong jet flow oriented almost directly laterally. During steady swimming,interception by the tail of the dorsal fin's vortical wake and the adipose fin's non-vortical (drag) wake is hypothesized as a mechanism for enhancing tail thrust. This study provides the first experimental evidence that the plesiomorphic soft dorsal fin of ray-finned fishes acts as an ancillary force generator during axial locomotion. We suggest that the distinction often made between median and paired fin (MPF) propulsion and body and caudal fin (BCF)propulsion in fishes obscures the important role of multiple propulsors acting in a coordinated fashion. Using a combination of anterior median fin oscillation and axial undulation, without continuous paired fin excursions,trout employ an `M–BCF' gait during steady swimming. The primarily lateral orientation of dorsal fin force in trout induces corresponding roll and yaw moments, which must be countered by forces from the caudal, anal and paired fins. Locomotion in trout therefore involves the simultaneous active use of multiple fins, presumably to maintain body stability in the face of environmental perturbations.
Insect gas exchange patterns: a phylogenetic perspective
Authors: Marais Elrike , Klok C. Jaco , Terblanche John S. , Chown Steven L.
Published: December 2005

Most investigations of insect gas exchange patterns and the hypotheses proposed to account for their evolution have been based either on small-scale,manipulative experiments, or comparisons of a few closely related species. Despite their potential utility, no explicit, phylogeny-based, broad-scale comparative studies of the evolution of gas exchange in insects have been undertaken. This may be due partly to the preponderance of information for the endopterygotes, and its scarcity for the apterygotes and exopterygotes. Here we undertake such a broad-scale study. Information on gas exchange patterns for the large majority of insects examined to date (eight orders, 99 species)is compiled, and new information on 19 exemplar species from a further ten orders, not previously represented in the literature (Archaeognatha,Zygentoma, Ephemeroptera, Odonata, Mantodea, Mantophasmatodea, Phasmatodea,Dermaptera, Neuroptera, Trichoptera), is provided. These data are then used in a formal, phylogeny-based parsimony analysis of the evolution of gas exchange patterns at the order level. Cyclic gas exchange is likely to be the ancestral gas exchange pattern at rest (recognizing that active individuals typically show continuous gas exchange), and discontinuous gas exchange probably originated independently a minimum of five times in the Insecta.
Assessment of Vitamin D Status in Male Osteoporosis
Authors: Al-oanzi Ziad H , Tuck Stephen P , Raj Nicholas , Harrop John S , Summers Gregory D , Cook David B , Francis Roger M , Datta Harish K
Published: December 2005

Background: Clinical assessment of vitamin D status often relies on measuring total circulating 25-hydroxyvitamin D3 (25OHD3), but much of each vitamin D metabolite is bound to plasma vitamin D–binding protein (DBP), such that the percentage of free vitamin is very low. We hypothesized that measurement of free rather than total 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and 25OHD3 may provide better assessment of vitamin D status. We therefore aimed to assess vitamin D status in men with idiopathic osteoporosis, in whom possible secondary causes of osteoporosis had been excluded, and to determine the extent of change in biologically active “free” vitamin D caused by variation in plasma DBP concentrations.

Methods: We measured 1,25(OH)2D3 and 25OHD3 in plasma samples from 56 men with idiopathic osteoporosis [mean (SD) age, 59.6 (13.6) years; range, 21–86 years] and 114 male controls [62.4 (10.4) years; range, 44–82 years].

Results: Mean total plasma 25OHD3 in the 56 men with osteoporosis and the 114 controls was 44.7 (21) and 43.3 (17) nmol/L, respectively; total plasma 1,25(OH)2D3 measured in randomly selected men with osteoporosis (n = 50) and controls (n = 50) was 90 (37) and 103 (39) pmol/L, respectively. Mean plasma DBP was significantly higher (P <0.001) in men with osteoporosis [224 (62) mg/L; n = 56] than in the controls [143 (34) mg/L; n = 114], but calculated free plasma 25OHD3 and 1,25(OH)2D3 were significantly lower in the osteoporotic men than in controls [6.1 (3.1) vs 9.1 (4.4) pmol/L (P <0.00001) and 77 (37) vs 142 (58) fmol/L (P <0.00001), respectively].

Conclusions: Measurement of total vitamin D metabolites alone, although providing a crude assessment of vitamin D status, may not give an accurate indication of the free (biologically active) form of the vitamin. The ratio of total 25OHD3 and 1,25(OH)2D3 to plasma DBP, rather than total circulating vitamin D metabolites, may provide a more useful index of biological activity. Further studies are required to substantiate this hypothesis.
Motor Memory Consolidation in Sleep Shapes More Effective Neuronal Representations
Authors: Fischer Stefan , Nitschke Matthias F. , Melchert Uwe H. , Erdmann Christian , Born Jan
Published: December 2005

Learning a motor skill involves a latent process of consolidation that develops after training to enhance the skill in the absence of any practice and crucially depends on sleep. Here, we show that this latent consolidation during sleep changes the brain representation of the motor skill by reducing overall the neocortical contributions to the representation. Functional magnetic resonance brain imaging was performed during initial training and 48 h later, at retesting, on a sequential finger movement task with training followed by either a night of regular sleep or sleep deprivation. An additional night of sleep for all subjects served to rule out unspecific effects of sleep loss at retrieval testing. Posttraining sleep, but not sleep deprivation, led to improved motor skill performance at retrieval. This sleep-dependent improvement was linked to greatly reduced brain activation in prefrontal, premotor, and primary motor cortical areas, along with a stronger involvement of left parietal cortical regions. Our findings indicate that storing a motor skill during sleep reorganizes its brain representation toward enhanced efficacy.
Control of Dendritic Arborization by the Phosphoinositide-3′-Kinase–Akt–Mammalian Target of Rapamycin Pathway
Authors: Jaworski Jacek , Spangler Samantha , Seeburg Daniel P. , Hoogenraad Casper C. , Sheng Morgan
Published: December 2005

The molecular mechanisms that determine the size and complexity of the neuronal dendritic tree are unclear. Here, we show that the phosphoinositide-3′ kinase (PI3K)–Akt–mammalian target of rapamycin (mTOR) signaling pathway promotes the growth and branching of dendrites in cultured hippocampal neurons. Constitutively active mutants of Ras, PI3K, and Akt, or RNA interference (RNAi) knockdown of lipid phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome Ten), induced growth and elaboration of dendrites that was blocked by mTOR inhibitor rapamycin and/or by overexpression of eIF-4E binding protein 1 (4E-BP1), which inhibits translation of 5′ capped mRNAs. The effect of PI3K on dendrites was lost in more mature neurons (>14 din vitro). Dendritic complexity was reduced by inhibition of PI3K and by RNAi knockdown of mTOR or p70 ribosomal S6 kinase (p70S6K, an effector of mTOR). A rapamycin-resistant mutant of mTOR “rescued” the morphogenetic effects of PI3K in the presence of rapamycin. By regulating global and/or local protein translation, and as a convergence point for multiple signaling pathways, mTOR could play a central role in the control of dendrite growth and branching during development and in response to activity.
Regulation of Dendritic Morphogenesis by Ras–PI3K–Akt–mTOR and Ras–MAPK Signaling Pathways
Authors: Kumar Vikas , Zhang Ming-Xiang , Swank Michael W. , Kunz Jeannette , Wu Gang-Yi
Published: December 2005

Dendritic arborization and spine formation are critical for the functioning of neurons. Although many proteins have been identified recently as regulators of dendritic morphogenesis, the intracellular signaling pathways that control these processes are not well understood. Here we report that the Ras–phosphatidylinositol 3-kinase (PI3K)–Akt–mammalian target of rapamycin (mTOR) signaling pathway plays pivotal roles in the regulation of many aspects of dendrite formation. Whereas the PI3K–Akt–mTOR pathway alone controlled soma and dendrite size, a coordinated activation together with the Ras-mitogen-activated protein kinase signaling pathway was required for increasing dendritic complexity. Chronic inhibition of PI3K or mTOR reduced soma and dendrite size and dendritic complexity, as well as density of dendritic filopodia and spines, whereas a short-term inhibition promoted the formation of mushroom-shaped spines on cells expressing constitutively active mutants of Ras, PI3K, or Akt, or treated with the upstream activator BDNF. Together, our data underscore the central role of a spatiotemporally regulated key cell survival and growth pathway on trophic regulation of the coordinated development of dendrite size and shape.
Novel Seizure Phenotype and Sleep Disruptions in Knock-In Mice with Hypersensitive α4*Nicotinic Receptors
Authors: Fonck Carlos , Cohen Bruce N. , Nashmi Raad , Whiteaker Paul , Wagenaar Daniel A. , Rodrigues-Pinguet Nivalda , Deshpande Purnima , McKinney Sheri , Kwoh Steven , Munoz Jose , Labarca Cesar , Collins Allan C. , Marks Michael J. , Lester Henry A.
Published: December 2005

A leucine to alanine substitution (L9′A) was introduced in the M2 region of the mouse α4 neuronal nicotinic acetylcholine receptor (nAChR) subunit. Expressed inXenopusoocytes, α4(L9′A)β2 nAChRs were ≥30-fold more sensitive than wild type (WT) to both ACh and nicotine. We generated knock-in mice with the L9′A mutation and studied their cellular responses, seizure phenotype, and sleep-wake cycle. Seizure studies on α4-mutated animals are relevant to epilepsy research because all known mutations linked to autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) occur in the M2 region of α4or β2 subunits. Thalamic cultures and synaptosomes from L9′A mice were hypersensitive to nicotine-induced ion flux. L9′A mice were ∼15-fold more sensitive to seizures elicited by nicotine injection than their WT littermates. Seizures in L9′A mice differed qualitatively from those in WT: L9′A seizures started earlier, were prevented by nicotine pretreatment, lacked EEG spike-wave discharges, and consisted of fast repetitive movements. Nicotine-induced seizures in L9′A mice were partial, whereas WT seizures were generalized. When L9′A homozygous mice received a 10 mg/kg nicotine injection, there was temporal and phenomenological separation of mutant and WT-like seizures: an initial seizure ∼20 s after injection was clonic and showed no EEG changes. A second seizure began 3-4 min after injection, was tonic-clonic, and had EEG spike-wave activity. No spontaneous seizures were detected in L9′A mice during chronic video/EEG recordings, but their sleep-wake cycle was altered. Our findings show that hypersensitive α4*nicotinic receptors in mice mediate changes in the sleep-wake cycle and nicotine-induced seizures resembling ADNFLE.
Modulation of NMDA Receptors by Pituitary Adenylate Cyclase Activating Peptide in CA1 Neurons Requires Gαq, Protein Kinase C, and Activation of Src
Authors: Macdonald D. S. , Weerapura M. , Beazely M. A. , Martin L. , Czerwinski W. , Roder J. C. , Orser B. A. , MacDonald J. F.
Published: December 2005

At CA1 synapses, activation of NMDA receptors (NMDARs) is required for the induction of both long-term potentiation and depression. The basal level of activity of these receptors is controlled by converging cell signals from G-protein-coupled receptors and receptor tyrosine kinases. Pituitary adenylate cyclase activating peptide (PACAP) is implicated in the regulation of synaptic plasticity because it enhances NMDAR responses by stimulating Gαs-coupled receptors and protein kinase A (Yaka et al., 2003). However, the major hippocampal PACAP1 receptor (PAC1R) also signals via Gαqsubunits and protein kinase C (PKC). In CA1 neurons, we showed that PACAP38 (1 nm) enhanced synaptic NMDA, and evoked NMDAR, currents in isolated CA1 neurons via activation of the PAC1R, Gαq, and PKC. The signaling was blocked by intracellular applications of the Src inhibitory peptide Src(40-58). Immunoblots confirmed that PACAP38 biochemically activates Src. A Gαqpathway is responsible for this Src-dependent PACAP enhancement because it was attenuated in mice lacking expression of phospholipase C β1, it was blocked by preventing elevations in intracellular Ca2+, and it was eliminated by inhibiting either PKC or cell adhesion kinase β [CAKβ or Pyk2 (proline rich tyrosine kinase 2)]. Peptides that mimic the binding sites for either Fyn or Src on receptor for activated C kinase-1 (RACK1) also enhanced NMDAR in CA1 neurons, but their effects were blocked by Src(40-58), implying that Src is the ultimate regulator of NMDARs. RACK1 serves as a hub for PKC, Fyn, and Src and facilitates the regulation of basal NMDAR activity in CA1 hippocampal neurons.
Chemical speciation of Am, Cm and Eu with EDTA at high ionic strength: thermodynamics and laser fluorescence spectroscopy studies
Authors: Cernochova K. , Mathur J. N. , Choppin Gregory R.
Published: December 2005

The complexation of Am3+, Cm3+ and Eu3+ with EDTA has been studied at an ionic strength of 6.60 mol kg−1 (NaClO4) and pcH 3.60 in the temperature range of 0 to 60 °C with a solvent extraction technique. The complex M(EDTA)− was formed with stability constant values (log β101) at 25 °C between 15.9 and 16.1 which increased with increasing temperature. The complex formation enthalpies have been obtained from the temperature dependence of the stability constants. The large positive enthalpy and entropy changes are attributed to the considerably reduced water activity at such high ionic strength resulting in large positive contributions from the dehydration of the trivalent metal ions as compared to the smaller negative contributions from the M3+–EDTA4− bonding interaction. The nature of the species of the EuEDTA complex formed at 6.60 mol kg−1 (NaClO4) and pcH ≥3.60 was studied by time-resolved laser fluorescence spectroscopy and lifetime measurements. Between pcH 3.60 and 7.0, Eu(EDTA)(H2O)3
− was formed while at pcH 9.0, Eu(OH)(EDTA)(H2O)2
2− was present.
Electrochemical and spectroelectrochemical behaviour of Np(VI) ions in nitric acid solutions
Authors: Kim Seong-Yun , Asakura Toshihide , Morita Yasuji
Published: December 2005

Electrochemical and spectroelectrochemical has been used to investigate the behaviour of neptunium (VI) in 1 ∼ 8 M HNO3solutions. The electrochemical reactions of Np(VI) ions were found to occurquasi-reversibly. The formal redox potentials (E°) for Np(VI)/Np(V) couples were determined to be +0.906, +0.908, +0.909, +0.902, +0.896, +0.895, +0.888, and +0.884 V (vs. Ag/AgCl) for Np(VI) ions in 1, 2, 3, 4, 5, 6, 7, 8 M HNO3solutions, respectively. The reduction processes of Np(VI) ions were followed spectroelectrochemically by using an optical transparent thin layer electrode cell. It was found that the absorption spectra measured at the applied potentials from +1.10 to +0.60 VversusAg/AgCl reference electrode redox couple for Np(VI) in HNO3solution have clear isosbestic points. These results indicate that the only reduction product of Np(VI) is Np(V), which is of considerable stability in HNO3solutions.
In vitro experimental study of the effect of radial shortening and ulnar ostectomy on contact patterns in the elbow joint of dogs
Authors: Preston Chris A. , Schulz Kurt S. , Taylor Ken T. , Kass Philip H. , Hagan Catherine E. , Stover Sue M.
Published: December 2005

Objective—To determine effects of incremental radial shortening and subsequent ulnar ostectomies on joint surface contact patterns in a canine elbow joint model.

Sample Population—Paired forelimbs from 9 adult dogs.

Procedure—Joint casting was performed by placement of colored polymethylmethacrylate in the elbow joint cavity and loading in a materials testing system at physiologic angle and load. Joint casting was performed in unaltered specimens, after radial shortening, and after subsequent distal ulnar ostectomy, proximal ulnar ostectomy, and proximal ulnar ostectomy with intramedullary pinning. Computer-aided analysis of photographs of proximal radial and ulnar articular surfaces without joint casts was performed before and after each casting procedure.

Results—All increments of radial shortening changed the size and location of radial and ulnar contact areas. The radial contact area became smaller, the anconeal contact area disappeared, the medial coronoid contact area migrated craniolaterally, and the lateral projection of the coronoid process became a contact area. A proximal ulnar ostectomy stabilized with an intramedullary pin restored normal contact area size and location and restored continuity of the radial and coronoid contact areas across the radioulnar articulation in 6 of 10 specimens. A midshaft ulnar ostectomy, distal to the level of the radioulnar ligament, had no effect on contact patterns. A proximal ulnar ostectomy without stabilization resulted in varus deformity during loading.

Conclusion and Clinical Relevance—Proximal radial shortening, which creates articular step incongruity, changes the location and size of the radioulnar contact areas. Dynamically stabilized ulnar ostectomies proximal to the radioulnar ligament restore contact patterns in vitro . (Am J Vet Res2001;62:1548–1556)
Effects of β-aminopropionitrile on equine tendon metabolism in vitro and on effects of insulin-like growth factor-I on matrix production by equine tenocytes
Authors: Dahlgren Linda A. , Nixon Alan J. , Brower-Toland Brent D.
Published: December 2005

Objective—To investigate effects of β-aminopropionitrile and a combination of insulin-like growth factor (IGF)-I and β-aminopropionitrile on metabolism of equine tendon fibroblasts.

Sample Population—Flexor tendon explants from 3 horses.

Procedure—Explants received 1 of 4 treatments (control, IGF-I, β-aminopropionitrile, and IGF-I/β-aminopropionitrile) for 10 days, and message expression for collagen types I and III was assessed by use of in situ hybridization. Histologic findings, new protein production, and quantitative determinations of glycosaminoglycan, DNA, and de novo collagen synthesis were made.

Results—Insulin-like growth factor-I stimulated an anabolic response in tendon. Collagen synthesis and glycosaminoglycan and DNA content of explants were all increased. β-Aminopropionitrile significantly suppressed collagen synthesis, which was not ameliorated by concurrent IGF-I treatment. β-Aminopropionitrile caused alterations in cell morphology characterized by large round cells with eccentric nuclei and decreased density of collagen fibers. Protein production and collagen type-III mRNA expression were reduced in these cells.

Conclusion and Clinical Relevance—Treatment with β-aminopropionitrile resulted in decreased production of protein and collagen synthesis, which could be expected to suppress tendon healing. The negative effects of β-aminopropionitrile could not be abrogated by addition of IGF-I to the medium. Treatment resulted in alterations in cell morphology and matrix consistency, which could further delay tendon healing. β-Aminopropionitrile may impair tendon healing at a cellular level by decreasing collagen production or increasing rate of degradation of existing matrix. Because of reduced crosslinking during β- aminopropionitrile treatment, in combination with transiently decreased tensile strength, alterations in collagen content and structure may weaken the healing tendon. (Am J Vet Res2001;62:1557–1562)
Development and evaluation of a highly sensitive and specific blocking enzyme-linked immunosorbent assay and polymerase chain reaction assay for diagnosis of bovine leukemia virus infection in cattle
Authors: Gutiérrez Silvina E. , Dolcini Guillermina L. , Arroyo Guillermo H. , Dubra Caín Rodriguez , Ferrer Jorge F. , Esteban Eduardo N.
Published: December 2005

Objective—To develop a blocking ELISA for detection of bovine leukemia virus (BLV) antibodies that is comparable to a radioimmunoprecipitation (RIP) assay, to evaluate use of this ELISA for identification of BLVinfected herds, and to develop a polymerase chain reaction (PCR) assay for direct diagnosis of infection with BLV.

Sample Population—Serum samples and pooled bulk-tank milk samples from cattle.

Procedure—The blocking ELISA was developed, using BLV gp51 as antigen, captured by a selected bovine polyclonal serum. A nested PCR was conducted with primers specific for a segment of thepolregion of the BLV genome.

Results—Sensitivity and specificity of the ELISA were comparable to those of the RIP assay. Use of the ELISA on pooled milk samples allowed identification of herds in which prevalence of BLV infection among lactating cows was as low as 2.5%. Pooled milk samples from BLV-free herds did not react in the ELISA. All cattle that had positive results for the nested PCR had BLV antibodies, but cattle with consistantly low antibody titers required examination of sequential DNA samples to detect viral sequences. None of the 63 antibodynegative cattle had positive results for the PCR.

Conclusion and Clinical Relevance—This ELISA is a highly specific and sensitive assay for the detection of BLV antibodies in serum and milk samples of cattle. Examination of pooled milk samples with the ELISA provides a reliable, practical, and economic procedure for identification of BLV-infected herds. The nested PCR also constitutes a specific procedure for direct diagnosis of infection with BLV. (Am J Vet Res2001;62:1571–1577)
Use of sample size for estimating efficacy of a vaccine against an infectious disease
Authors: Carpenter Tim E.
Published: December 2005

Objective—To determine the sample size necessary to evaluate the efficacy of a vaccine in a population.

Procedure—An equation was coded into a computer spreadsheet to compare the traditional sample size calculation with that needed when evaluating the efficacy of a vaccine applied in a population.

Results—The traditional approach used to conservatively estimate sample size necessary to detect a given difference in group proportions potentially greatly underestimates the number of animals needed for vaccine efficacy (VE) trials. In VE trials, it is necessary to estimate the effect of population-level vaccination prior to estimating sample size. In VE trials, as incidence proportion in the population or herd decreases or VE decreases, necessary sample size increases.

Conclusion and Clinical Relevance—In designing a clinical or field trial, such as one to evaluate the efficacy of a vaccine against an infectious disease in a population, one needs to approach sample size calculations in a nontraditional manner. The proportion of the population vaccinated, disease transmission dynamics, and VE will affect the incidence in the nonvaccinated and vaccinated groups and, hence, sample size. Thus, estimation of the effect of the vaccination on the population must be made prior to calculating sample size. Otherwise, sample size and the power to identify VE will be insufficient. (Am J Vet Res2001;62:1582–1584)
Cytologic and biochemical changes associated with inoculation of amniotic fluid and meconium into lungs of neonatal rats
Authors: Martínez-Burnes Julio , López Alfonso , Horney Barbara , MacKenzie Allan , Brimacombe Michael
Published: December 2005

Objective—To evaluate the effect of homologous amniotic fluid and meconium inoculated intratracheally into the lungs of neonatal rats.

Animals—153 male 7-day-old Fischer-344 rats.

Procedure—Amniotic fluid was obtained by cesarean section from the uterus of pregnant rats and meconium was collected at the time of birth from the gastrointestinal tract of neonatal rats. Neonatal rats were randomly allocated into 5 treatment groups. Two groups received 0.05 ml of saline (0.9% NaCl) solution; the third and fourth groups received 0.05 ml of 50% or 100% amniotic fluid, respectively; the fifth group was inoculated with 0.05 ml of a 20% suspension of meconium. Six or 7 rat pups/group were euthanatized by exsanguination under halothane anesthesia at postinoculation days 1, 3, 7, and 14. The magnitude of injury and inflammatory response was determined by biochemical and cytologic analyses of bronchoalveolar lavage fluid.

Results—Inoculation with saline solution and amniotic fluid did not induce pulmonary injury or inflammatory response. Inoculation with meconium induced significant ( P < 0.01) injury and inflammatory response, characterized by the release of cytosolic enzymes and recruitment of neutrophils in the lung.

Conclusion and Clinical Relevance—Saline solution is an innocuous vehicle that can be safely used in intratracheal inoculations in neonatal rats. Homologous amniotic fluid, despite containing keratin and epidermal cells, does not cause acute injury or inflammation in the lung. In contrast, meconium acts as a toxic substance injuring respiratory cells and causing a vigorous but transient leukocytic inflammatory reaction in the lungs. (Am J Vet Res2001;62:1636–1641)
Evaluation of ultrastructural changes associated with encephalomyocarditis virus in the myocardium of experimentally infected piglets
Authors: Psychas Vassilios , Papaioannou Nikolaos , Billinis Charalampos , Paschaleri-Papadopoulou Efpraxia , Leontides Sotirios , Papadopoulos Orestis , Tsangaris Thomas , Vlemmas John
Published: December 2005

Objective—To evaluate the ultrastructural changes and localization of encephalomyocarditis virus (EMCV) and viral pathogenesis in the myocardium of experimentally infected piglets.

Animals—Eight 20-day-old piglets.

Procedure—Six piglets were inoculated oronasally with 5 ml (106median tissue culture infective dose/ml) of EMCV suspension, and 2 were used as uninfected controls. Piglets were euthanatized or died between postinoculation days 1 and 3. Samples of heart tissue from all piglets were evaluated histologically, by virus isolation, and by use of immunohistochemistry and electron microscopy.

Results—All infected piglets had gross or microscopic lesions of interstitial myocarditis. immunohistochemically, EMCV antigen was detected in the cytoplasm of cardiac muscle cells, Purkinje fibers, and endothelial cells and in the nucleus of cardiac muscle cells and Purkinje fibers. Ultrastructural lesions were characterized by degeneration and necrosis of cardiac muscle cells and Purkinje fibers. Virus was present intracytoplasmically in cardiac muscle cells, Purkinje fibers, and endothelial cells of capillaries and intranuclearly in cardiac muscle cells. The cell membranes of the Purkinje fibers and endothelial cells had distinct protrusions that contained virus particles. In control piglets, no lesions were found, and no EMCV antigen was detected.

Conclusion and Clinical Relevance—Localization of EMCV intracytoplasmically or intranuclearly in various myocardial cells may well reflect the sites of viral proliferation. The presence of virus particles in cell membrane protrusions and in vacuoles within the lumen of capillaries indicates that virus is released not only by disintegration of the host cell but also via exocytosis. (Am J Vet Res2001;62:1653–1657)
Effect of immunosuppressive doses of cyclosporine on pancreatic beta cell function in pigs
Authors: Dean Sophia K. , Scott Hayley , Keogh Gregory W. , Roberts Simon , Tuch Bernard E.
Published: December 2005

Objective—To evaluate whether immunosuppressive doses of cyclosporine (CsA) have an adverse effect on the liver, kidney, and pancreatic beta cells of pigs.

Animals—8 juvenile 8-week-old Landrace X Large White crossbred pigs.

Procedure—CsA (100 to 140 mg/kg) was administered orally to euglycemic pigs to reach whole blood trough concentrations of approximately 1500 ng/mL. To determine pancreatic beta cell function, plasma Cpeptide and insulin concentrations were measured in response to IV administration of glucose, glucagon, arginine, and oral administration of glucose. Effects on liver and kidney were determined by monitoring serum measurements of liver function and serum creatinine concentrations, respectively.

Results—Plasma concentrations of C-peptide were significantly lower in euglycemic CsA-treated pigs, compared with control pigs, following IV administration of glucose, glucagon, arginine, and oral administration of glucose. Furthermore, the glucose clearance rate was decreased in euglycemic CsA-treated pigs, compared with control pigs. Serum creatinine concentrations and 4 of 7 serum measurements of liver function were not adversely affected by CsA administration. Serum concentrations of bilirubin and albumin were significantly increased, and serum alanine aminotransferase activity was significantly decreased in CsA-treated pigs, compared with control pigs. Histologic evaluation of liver and kidney sections revealed no pathologic findings in CsA-treated or control pigs.

Conclusions and Clinical Relevance—In our study, immunosuppressive doses of CsA caused an impairment of porcine pancreatic beta cell function, but did not have toxic effects on the kidney. However, on the basis of changes in serum bilirubin and albumin concentrations and alanine aminotransferase activity, subclinical toxic effects on the liver did occur when immunosuppressive doses of CsA were administered. (Am J Vet Res2002;63:1501–1506)
Effects of an adenosine kinase inhibitor and an adenosine deaminase inhibitor on accumulation of extracellular adenosine by equine articular chondrocytes
Authors: Tesch Anthony M. , MacDonald Melinda H. , Kollias-Baker Cynthia , Benton Hilary P.
Published: December 2005

Objective—To investigate accumulation of extracellular adenosine (ADO) by equine articular chondrocytes and to compare effects of adenosine kinase inhibition and adenosine deaminase inhibition on the amount of nitric oxide (NO) produced by lipopolysaccharide (LPS)-stimulated chondrocytes.

Sample Population—Articular cartilage from metacarpophalangeal and metatarsophalangeal joints of 14 horses.

Procedure—Chondrocytes were cultured as monolayers, and cells were incubated with LPS, the adenosine kinase inhibitor 5'-iodotubercidin (ITU), or the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3- nonyl)adenine hydrochloride (EHNA). Concentrations of ADO in cell supernatants were measured by use of reverse-phase high-performance liquid chromatography. Effect of inhibition of enzymatic metabolism of ADO on induced NO production was evaluated by exposing cells to a combination of LPS and ITU or LPS and EHNA.

Results—Articular chondrocytes accumulated extracellular ADO when exposed to LPS or ITU. Chondrocytes exposed to ITU accumulated ADO in a time-dependent manner. Unstimulated chondrocytes did not accumulate ADO. Similarly, EHNA alone did not produce detectable ADO concentrations; however, addition of EHNA and ITU resulted in a synergistic effect on accumulation of ADO. Lipopolysaccharideinduced NO production was more effectively suppressed by exposure to ITU than to EHNA

Conclusions and Clinical Relevance—Equine articular chondrocytes release ADO in response to the proinflammatory stimulus of bacterial LPS. Inhibition of the metabolism of ADO increases accumulation of extracellular ADO. Autocrine release of ADO from chondrocytes may play a role in the cellular response to tissue damage in arthritic conditions, and pharmacologic modulation of these pathways in joints of arthritic horses could be a potential method of therapy. (Am J Vet Res2002;63:1512–1519)
Binding of radiolabeled porcine motilin and erythromycin lactobionate to smooth muscle membranes in various segments of the equine gastrointestinal tract
Authors: Koenig Judith B. , Cote Nathalie , LaMarre Jonathan , Harris William H. , Trout Donald R. , Kenney Daniel G. , Monteith Gabrielle
Published: December 2005

Objective—To identify and characterize motilin receptors in equine duodenum, jejunum, cecum, and large colon and to determine whether erythromycin lactobionate competes with porcine motilin for binding to these receptors.

Sample Population—Specimens of various segments of the intestinal tracts of 4 adult horses euthanatized for reasons unrelated to gastrointestinal tract disease.

Procedure—Cellular membranes were prepared from smooth muscle tissues of the duodenum, jejunum, pelvic flexure, and cecum. Affinity and distribution of motilin binding on membrane preparations were determined by use of125I-labeled synthetic porcine motilin. Displacement studies were used to investigate competition between125I-labeled synthetic porcine motilin and erythromycin lactobionate for binding to motilin receptors in various segments of bowel.

Results—Affinity of125I-labeled synthetic porcine motilin for the equine motilin receptor was estimated to be 6.1nM. A significantly higher number of motilin receptors was found in the duodenum than in the pelvic flexure and cecum. The jejunum had a significantly higher number of motilin receptors than the cecum. Erythromycin lactobionate displacement of125I-labeled porcine motilin from the equine motilin receptor did not differ significantly among various segments of bowel.

Conclusions and Clinical Relevance—Motilin receptors were found in the duodenum, jejunum, pelvic flexure, and cecum of horses. The highest number of motilin receptors was in the duodenum, and it decreased in more distal segments of bowel. Erythromycin lactobionate competed with motilin binding in the equine gastrointestinal tract. This suggests that 1 of the prokinetic actions of erythromycin in horses is likely to be secondary to binding on motilin receptors. (Am J Vet Res2002;63:1545–1550)