Whole transcriptome analysis of the pectoralis major muscle reveals molecular mechanisms involved with white striping in broiler chickens.

White striping (WS) is one of the most common myopathies identified in broiler chickens leading to substantial production losses, where the incidence reaches 12% in commercial chickens. It occurs primarily in heavier chickens being a modification of the breast muscle characterized by the presence of pale parallel streaks in the same orientation of the muscle fibers. Since the WS etiology remains unclear, we aimed to identify the biological and genetic mechanisms involved in its occurrence through the whole transcriptome analysis of WS in affected and unaffected chicken breast muscles. A total of 11,177 genes were expressed in the pectoralis major muscle. Out of those, 1,441 genes were differentially expressed (FDR ≤ 0.01) between the two analyzed groups, being, respectively, 772 genes upregulated and 669 downregulated in the WS affected group. A total of 36 significantly overrepresented GO terms related to WS myopathy were enriched, and the most relevant biological processes were activation of immune system, angiogenesis, hypoxia, cell death, and striated muscle contraction. The unbalance of those biological processes may trigger the occurrence of the WS phenotype in broilers. The possible lack of capillary blood supply homogeneously in the muscle triggers the hypoxia, following the activation of glycolysis, calcium signaling and apoptosis related genes facilitating the tissue damage and WS incidence.

Double inversion recovery sequence of the cervical spinal cord in multiple sclerosis and related inflammatory diseases.

BACKGROUND AND PURPOSE: MR imaging plays an important role in diagnosing MS and other related inflammatory diseases; however, imaging of the spinal cord is still challenging. We hypothesized that a 3D double inversion recovery sequence for cervical spinal cord imaging would be more sensitive in detecting inflammatory lesions than a conventional 2D T2-weighted TSE sequence at 3T. MATERIALS AND METHODS: On a 3T MR imaging scanner, we examined 30 patients with suspected or established MS (MS, n = 16; clinically isolated syndrome, n = 12; isolated myelitis, n = 2) and 10 healthy controls. Newly developed 3D double inversion recovery and conventional 2D axial and sagittal T2-weighted TSE images of the cervical spinal cord were acquired. Two blinded neuroradiologists independently assessed the scans in pseudorandomized order for lesion numbers and rated lesion visibility and overall image quality on 5-point scales. A subsequent consensus reading delivered definite lesion counts. Standardized contrast-to-noise ratios were calculated in representative lesions of each patient. RESULTS: Overall, 28% more lesions could be detected with 3D double inversion recovery than with conventional T2WI (119 versus 93, P < .002). On average, the standardized contrast-to-noise ratio was significantly higher (P < .001) in double inversion recovery than in T2WI. Lesion visibility was rated significantly higher (P < .001) in double inversion recovery compared with T2WI despite lower image quality. CONCLUSIONS: The novel 3D double inversion recovery sequence allowed better detection of lesions in MS and related inflammatory diseases of the cervical spinal cord, compared with conventional 2D T2WI.

Inversion-recovery single-shot cardiac MRI for the assessment of myocardial infarction at 1.5 T with a dedicated cardiac coil.

OBJECTIVE: The aim of this study was to assess the diagnostic accuracy of imaging myocardial infarction with a two-dimensional (2D) single-shot inversion-recovery (IR)-gradient-echo (GE) sequence compared with a standard 2D segmented IR-GE sequence at 1.5 T using a dedicated cardiac coil. METHODS: 22 patients with myocardial infarction documented in the past 3-12 months were examined at 1.5 T using a 5 channel cardiac coil. Imaging of delayed enhancement was performed 15 min after administration of 0.2 mmol of gadopentetate dimeglumine per kilogram of body weight. Immediately after completion of the single-shot sequence, which allows for coverage of the entire ventricle during a single breath-hold with nine slices, the segmented IR sequence was started. Infarct volumes, infarct transmurality and contrast-to-noise ratios (CNRs) of infarcted and healthy myocardium were compared between both techniques. RESULTS: Despite a moderate, non-significant loss of CNR (CNR(single-shot IR)=31.2±4.1; CNR(segmented IR)=37.9±4.1; p=0.405), the 2D single-shot technique correctly determined infarct size when compared with the standard 2D segmented IR-GE sequence. Assessment of both infarct volume (r=0.95; p<0.0001) and transmurality (r=0.97; p<0.0001) is possible, with excellent correlation of both techniques. CONCLUSION: Single-shot delayed enhancement imaging during a single breath-hold is feasible at 1.5 T with the use of a dedicated cardiac coil. Despite a moderately lower CNR, the single-shot technique allows for fast and accurate determination of infarct size with high spatial resolution and has the potential to reduce electrocardiogram and breathing artefacts.

Identification of loci associated with tolerance to Johne's disease in Holstein cattle.

Johne's disease, caused by Mycobacterium avium subspecies paratuberculosis (Map), is a fatal disease in cattle. The objective of this study was to identify loci associated with tolerance in cows infected with Map. Tolerance was defined as a cow's fitness at a given level of Map infection intensity. Fitness was measured by Map faecal cultures, and Map infection intensity was measured by culturing four gut tissues. The quantitative phenotype of tolerance was defined by numerical indexes of cultures of peak (peak tolerance, PT) and average (average tolerance, AT) faecal and tissue Map from 245 Holstein cows. The categorical phenotype was defined as: ≥ 100 cfu Map tissue infection, and faecal shedding ≥ 75 cfu (intolerant) or <10 cfu (tolerant cows). In 94 cows, Map was identified in ≥ 1 tissue, including 44 cows with ≥ 100 Map tissue cfu and 36 with ≥ 1 faecal cfu. A genome-wide association analysis was performed after filtering, leaving genotypes for 45,789 SNPs in 90 animals for the quantitative phenotype and 16 cases and 25 controls for the categorical analysis of tolerance. rs41748405:A>C (BTA15) was associated with PT (P = 1.12 × 10(-7)) and AT (P = 2.17 × 10(-6)). Associations were identified with PT and adjacent SNPs ss61512613:A>G and ss61530518:A>G (BTA6) (P < 3.0 × 10(-5)), and with AT for ss61469568:A>G (BTA 2) (P = 3.3 × 10(-5)) and ss86284768:A>G (BTA1) (P = 3.31 × 10(-5)). For the categorical phenotype, an association was found with ss8632653:A>G (BTA6) (P < 5.0 × 10(-5)). This is the first study to identify loci associated with tolerance to Johne's disease.

The influence of collagen network integrity on the accumulation of gadolinium-based MR contrast agents in articular cartilage.

PURPOSE: Delayed gadolinium-enhanced MR imaging of cartilage is used to quantify the proteoglycan loss in early osteoarthritis. It is assumed that T1 after Gd-DTPA administration in the near equilibrium state reflects selective proteoglycan loss from cartilage. To investigate the influence of the collagen network integrity on contrast accumulation, the relaxation rates ΔR(1) and ΔR(2) were compared after Gd-DTPA administration in a well established model of osteoarthritis. MATERIALS AND METHODS: Collagen or proteoglycan depletion was induced by the proteolytic enzymes papain and collagenase in healthy bovine patellar cartilage. Using a dedicated MRI sequence, T(1) and T(2) maps were simultaneously acquired before and 11 h after Gd-DTPA administration. Depth-dependent profiles of ΔR(1) and ΔR(2) were calculated in healthy, proteoglycan and collagen-depleted articular cartilage and the mean values of different cartilage layers were compared using the Mann-Whitney-U test. RESULTS: In superficial layers (1 mm) there was no significant difference (p > 0.05) in either ΔR(1) or ΔR(2) between proteoglycan-depleted (16.6 ± 1.2 s(-1), 15.9 ± 1.0 s(-1)) and collagen-depleted articular cartilage (15.3 ± 0.9 s(-1), 15.5 ± 0.9 s(-1)). In deep layers (3 mm) both parameters were significantly higher (p = 0.005, 0.03) in proteoglycan-depleted articular cartilage (12.3 ± 1.1 s(-1), 9.8 ± 0.8 s(-1)) than in collagen-depleted articular cartilage (9.1 ± 1.1 s(-1), 8.7 ± 0.7 s(-1)). CONCLUSION: Both proteoglycan loss and alterations in the collagen network influence the accumulation of Gd-DTPA in articular cartilage with significant differences between superficial and deep cartilage layers.

A whole genome association analysis identifies loci associated with Mycobacterium avium subsp. paratuberculosis infection status in US holstein cattle.

The purpose of this study was to identify loci associated with Mycobacterium avium subspecies paratuberculosis (Map) infection status in US Holsteins using the Illumina BovineSNP50 BeadChip whole genome single nucleotide polymorphism (SNP) assay. Two hundred forty-five cows from dairies in New York, Pennsylvania and Vermont enrolled in longitudinal herd studies between January 1999 and November 2007 were assessed for the presence of Map in both faecal and tissue samples. An animal was considered tissue infected if any sample contained at least one colony forming unit of Map per gram of tissue (CFU/g) and the same definition was employed for faecal samples. Each animal was genotyped with the Illumina BovineSNP50 BeadChip and after quality assurance filtering, 218 animals and 45 683 SNPs remained. We sought to identify loci associated with four different case/control classifications: presence of Map in the tissue, presence of Map in faeces, presence of Map in both tissue and faeces and presence of Map in tissue but not faeces. A case-control genome wide association study was conducted to test the four different classifications of Map infection status (cases) when compared with a Map-negative control group (control). Regions on chromosomes 1, 5, 7, 8, 16, 21 and 23 were identified with moderate significance (P < 5 x 10(-5)). Two regions, one on chromosome 3 (near EDN2) and another on chromosome 9 (no positional gene candidates), were identified with a high level of association to the presence of Map in tissue and both tissue and faeces respectively (P < 5 x 10(-7), genome-wide Bonferonni P < 0.05).

Prospective study on bright lumen magnetic resonance colonography in comparison with conventional colonoscopy.

The aim of this prospective trial was to evaluate sensitivity and specificity of bright lumen magnetic resonance colonography (MRC) in comparison with conventional colonoscopy (CC). A total of 120 consecutive patients with clinical indications for CC were prospectively examined using MRC (1.5 Tesla) which was then followed by CC. Prior to MRC, the cleansed colon was filled with a gadolinium-water solution. A 3D GRE sequence was performed with the patient in the prone and supine position, each acquired during one breathhold period. After division of the colon into five segments, interactive data analysis was carried out using three-dimensional post-processing, including a virtual intraluminal view. The results of CC served as a reference standard. In all patients MRC was performed successfully and no complications occurred. Image quality was diagnostic in 92% (574/620 colonic segments). On a per-patient basis, the results of MRC were as follows: sensitivity 84% (95% CI 71.7-92.3%), specificity 97% (95% CI 89.0-99.6%). Five flat adenomas and 6/16 small polyps (< or =5 mm) were not identified by MRC. MRC offers high sensitivity and excellent specificity rates in patients with clinical indications for CC. Improved MRC techniques are needed to detect small polyps and flat adenomas.

Detection of hepatocellular carcinoma: comparison of Gd-DTPA- and ferumoxides-enhanced MR imaging.

The aim was to compare the diagnostic performance of dynamic Gd-DTPA- and ferumoxides-enhanced MRI for hepatocellular carcinoma (HCC). Twenty-five patients with chronic hepatitis or liver cirrhosis underwent both dynamic gadopentetate- and ferumoxides-enhanced MRI studies of the liver for HCC detection on the same day. MR data of both studies were retrospectively and independently analyzed. Two observers determined in consensus the grade of diffuse fibrotic liver changes (mild, moderate or severe) and the number of focal lesions. HCCs were confirmed by histology (n=22) and/or follow-up studies for at least six months (n=64). Differences in results obtained from both MR data sets were tested for significance with the McNemar's test (p<0.05). Ferumoxides-enhanced MR images detected 84 of 99 hepatic lesions, including 82 of 86 HCCs and 2 false positive, nonmalignant lesions, while Gd-DTPA-enhanced MR images detected 92 of 99 hepatic lesions, including 81 of 86 HCCs and 11 false positive, nonmalignant lesions. Sensitivity of MRI for detection of HCCs was not significantly different between ferumoxides-enhanced (95.3%; p>0.05) and Gd-DTPA-enhanced scans (94.2%). Gd-DTPA- and ferumoxides-enhanced MRI perform equally well for HCC detection. The majority of small hypervascular hepatic lesions, detected on dynamic Gd-DTPA-enhanced MRI but not on ferumoxides-enhanced MRI, represent no HCCs.

Evaluation of reconstructed orbital wall fractures: high-resolution MRI using a microscopy surface coil versus 16-slice MSCT.

We evaluated high-resolution magnetic resonance imaging (MR) using a 47-mm microscopy surface coil in comparison to 16-slice multislice CT (MSCT) for postsurgical imaging of reconstructed orbital walls. Twenty-five patients with 27 internal orbital wall fractures were imaged prospectively after reconstruction with resorbable polydioxanone sulfate (PDS) sheets. Coronal high-quality T1- and T2-weighted MR images were obtained with an in-plane resolution of 350 microm within a measure time of 6-7 min for each sequence. Nineteen symptomatic patients underwent MSCT as the current gold standard. In MRI the PDS foil appears in T1- and T2-weighted images as a thin, low-signal-intensity linear structure. In CT it appears hyperdense in comparison to soft tissue and slightly hypodense in comparison to cortical bone. PDS foils could be clearly depicted in 20 out of 25 patients (80%) with MRI and in 13 out of 19 patients (68%) with MSCT. An inadequate foil position or size could be diagnosed in eight patients with MRI and in only three patients with MSCT. In ten symptomatic patients secondary surgery could be avoided because of regular MRI findings except mild hematoma and muscle edema. High-resolution MRI of the orbit using a 47-mm microscopy coil is a promising method to accurately demonstrate normal and pathologic conditions in symptomatic patients after orbital wall reconstruction with PDS foils.

Observation of the swallowing process by application of videofluoroscopy and real-time magnetic resonance imaging-consequences for retronasal aroma stimulation.

The process of eating and drinking was observed in vivo by application of videofluoroscopy, a dynamic X-ray technique, as well as real-time magnetic resonance imaging. The study was aimed at elucidating the timing and performance of the physiological organs involved in mastication and swallowing, mainly the tongue, the pharynx and the soft palate (velum palatinum). It was shown for the first time that effective physiological barriers do exist during food consumption that are capable of retaining volatiles such as helium within the oral cavity. These barriers allow the access of odorants to the nasal cavity only at certain times during the eating process. Their effectiveness is related to the texture of the food as well as the amount of food material present in the oral cavity and, thereby, directly influences retronasal aroma perception.

[Virtual endoscopy of the urinary tract from T(2)-weighted and gadolinium-enhanced T(1)-weighted MR urographic images]. / Virtuelle Endoskopie des Urogenitaltraktes auf der Basis T(2)-gewichteter und kontrastmittelunterstützter T(1)-gewichteter Datensätze.

PURPOSE: To determine the diagnostic performance of T(2)-weighted (T2w) and gadolinium-enhanced T(1)-weighted (T1w-Gd-enhanced) MR urographic images for virtual endoscopy of the urinary tract. MATERIALS AND METHODS: 36 patients underwent MR urography at 1.5 T. In each patient a T2w (3D-TSE, respiration-triggered) and a T1w-Gd-enhanced sequence (T1-FFE, breathhold) were acquired. Data reconstruction was performed as maximum intensity projection (MIP) and virtual endoscopy (VE). RESULTS: Combined analysis of MIP and VE delineated 32 of 36 pathologies; 86 % (19/22) of intraluminal pathologies could be depicted by VE and 15 % (3/22) by MIP (p

The quantification of DeltaR2(*) under brain activation: dependence on relaxation rate at rest and significance threshold.

Transverse relaxation rates R2(*) were measured in subjects performing a motor task using a segmented EPI double gradient echo sequence (TE = 23/70 ms) with five different voxel sizes between 1.8 mm(3) and 41.7 mm(3). An analysis of the errors involved in the calculation of the change of the transverse relaxation rate--DeltaR2(*) and of the consequences of defining an arbitrary threshold of statistical significance in the data analysis was performed. Correlations between the magnitude of the BOLD effect and the significance level on one hand and between the transverse relaxation time at rest and its change under activation on the other, both referenced in the literature, can be understood as a consequence of this procedure. Analysing histograms of parameter changes rather than average values alone allows for an estimate of the contribution of false positive voxels. Furthermore, while the averaged signal change increases in proportion to the selection threshold the histograms of activated voxels remain insensitive to the latter.

Solvent composition and viscosity effects on the kinetics of CO binding to horse myoglobin.

Ligand binding to myoglobin in aqueous solution involves two kinetic components, one extramolecular and one intramolecular, which have been interpreted in terms of two sequential kinetic barriers. In mixed solvents and sub-zero temperatures, the outer barrier increases and the inner barrier splits into several components, giving rise to fast intramolecular recombination. The nature of these barriers and their relation to structural relaxation are examined using the effect of solvent composition and viscosity on the kinetics of CO binding to horse myoglobin in 60% ethylene glycol/water, 75% and 90% glycerol/water, 80% and 92% sucrose/water solutions. Measurements of the corresponding solvent structural relaxation rates by frequency resolved calorimetry allow us to discriminate between solvent composition and viscosity-related effects. The outer kinetic barrier controlling ligand entry and release depends on the viscosity consistent with Kramers-Stokes law of activated escape in the presence of friction. At high cosolvent concentration, we observe deviations from Stokes law, implying a smaller microviscosity at the protein-solvent interface as compared to the bulk. The inner barrier and its coupling to structural relaxation appears to be independent of viscosity but changes with solvent composition. As a possible explanation, we discuss the role of distal water molecules in the formation of the effective inner barrier. At low temperatures, this barrier has a distributed height, depending only slightly on the nature of the cosolvent and temperature at low cosolvent concentrations. In contrast, myoglobin embedded in a sucrose glass (92% sucrose/water) exhibits a temperature-dependent and bimodal enthalpy distribution. This result demonstrates that the exchange between protonation states of His64, A0 left and right arrow A1, can take place in the glass and at temperatures as low as 80 K.

Structural relaxation and nonexponential kinetics of CO-binding to horse myoglobin. Multiple flash photolysis experiments.

The geminate recombination kinetics of CO-myoglobin strongly deviates from single exponential behavior in contrast to what is expected for unimolecular reactions (1). At low temperatures, this result was attributed to slowly exchanging conformational states which differ substantially in barrier height for ligand binding. Above 160 K the kinetics apparently slow down with temperature increase. Agmon and Hopfield (2) explain this result in terms of structural relaxation perpendicular to the reaction coordinate, which enhances the activation energy. In their model, structural relaxation homogenizes the kinetic response. Recently, Steinbach et al. (3) proposed a relaxation model which conserves the kinetic inhomogeneity. Below we test these conjectures by single and multiple excitation experiments. This method allows for discrimination between parallel (inhomogeneous) and sequential (homogeneous) kinetic schemes. The kinetic anomaly above 160 K is shown to result from a homogeneous, structurally relaxed intermediate. However a second anomaly is found above 210 K concerning the inhomogeneous phase which may indicate either a shift in activation energy or entropy.

Solvent damping of internal processes in myoglobin studied by specific heat spectroscopy and flash photolysis.

We address the question of dynamic coupling between protein and solvent by comparing the enthalpy relaxation of the solvent (75% v/v glycerol-water) to internal ligand binding in myoglobin. When the solvent relaxation is slow compared to intramolecular events we observe decoupling of protein motions from the solvent. In the opposite limit there is a significant contribution of the solvent to internal friction. The solvent enhances the apparent activation energy of transitions in myoglobin. This result is discussed in terms of a generalized Kramer's law involving a dynamic friction coefficient.

Human immunodeficiency virus type 1-infected individuals make autoantibodies that bind to CD43 on normal thymic lymphocytes.

Sera from human immunodeficiency virus type 1 (HIV-1)-infected and -noninfected individuals were screened for antibodies that could bind to native T cell differentiation antigens. Antibodies that could immunoprecipitate CD43 (sialophorin, leukosialin) from a T cell lymphoma line were detected in sera from 27% of patients, and antibodies that could bind specifically to transfected cells expressing CD43 were detected in 47% of patients. The anti-CD43 antibodies were related to HIV-1 infection in that no patients with other chronic viral infections or systemic lupus erythematosus contained such antibodies in their sera. The anti-CD43 autoantibodies bound to a partially sialylated form of CD43 expressed by normal human thymocytes, but not by normal, circulating T lymphocytes. However, the determinant(s) recognized by the anti-CD43 autoantibodies was present on a large proportion of circulating T lymphocytes, but masked from antibody recognition by sialic acid residues. These results demonstrate that HIV-1 infection is specifically associated with the production of autoantibodies that bind to a native T cell surface antigen.

Surface immunoglobulin-positive T lymphocytes in HIV-1 infection: relationship to CD4+ lymphocyte depletion.

T lymphocytes bound to autologous immunoglobulin (surface Ig + T cells) and serum antibodies that bind to allogeneic lymphocytes have been detected in HIV-1-infected individuals, but their significance in the immunopathogenesis of HIV-1 infection is uncertain. We tested peripheral blood from HIV-1-infected individuals to determine if surface Ig+ T cells are specific for HIV-1 infection and are associated with CD4+ lymphocyte depletion. The majority of HIV-1-infected individuals contained substantial numbers of circulating surface Ig+ T cells. The presence of such cells was restricted to seropositive individuals and not related to risk factors associated with the acquisition of HIV-1 infection. Autologous immunoglobulin was detected on both CD4+ and CD8+ cells in all patients tested. Most individuals with surface Ig+ T lymphocytes also had serum anti-T-lymphocyte antibodies. The presence of surface Ig+ T lymphocytes correlated significantly with lower absolute CD4+ lymphocyte counts only in asymptomatic, HIV-1-infected individuals.

Percolation model of ionic channel dynamics.

The nonexponential closed-time distributions observed for ionic channels have been explained recently by quasi-one-dimensional models of structural diffusion (Millhauser, G. L., E. E. Salpeter, and R. E. Oswald. 1988. Proc. Natl. Acad. Sci. USA. 85: 1503-1507; Condat, C. A., and J. Jäckle. 1989. Biophys. J. 55: 915-925; Levitt, D. G. 1989. Biophys. J. 55: 489-498). We generalize this treatment by allowing for more complex trajectories using percolation theory. We assume that the gating transition depends on marginally connected conformational states leading to the observed spread in time scales.