Structural and functional analysis of the signaling lymphocytic activation molecule family 7 (SLAMF7) gene in response to infection with coagulase-negative and coagulase-positive staphylococci.

Splice variants of the signaling lymphocytic activation molecule family 7 (SLAMF7) gene have been identified, and differences in the expression of this gene have been demonstrated at the mRNA level in the mammary glands of healthy and mastitis-infected dairy cows. At the same time, significant associations have been found between a deletion in the SLAM7 gene exon, the occurrence of different splice variants, and the occurrence of mastitis in one group of dairy cows. An expression study was conducted on 40 Polish Holstein-Friesian dairy cows of the Black and White variety (group I). Milk samples were taken for microbiological analysis 2 d before slaughter and examined for the presence of bacteria. Immediately after slaughter, mammary tissue samples were taken and divided into 3 groups according to the health status of the mammary gland: healthy (without pathogenic bacteria in milk), coagulase-negative staphylococci (CNS), and coagulase-positive staphylococci (CPS). Based on different SLAMF7 gene DNA fragments, 2 alternative variants of this gene (V1 and V2) and complete gene expression were identified. Separate analyses performed for each isoform showed that the health status of the cow was strongly associated with the expression level of individual variants. The highest expression was detected for the SLAMF7 complete amplicon in healthy cows, and in the CNS and CPS cows the expression of this variant was also higher than V1 and V2. Sanger sequencing was applied to detect the polymorphism/indel variant in the second exon of the SLAMF7 gene probably having the greatest effect on the protein structure and function of SLAMF7. Two genotypes were detected: AA (wild-type) and AB (insertion A). In healthy cows, the frequency of homozygotes AA was higher than the heterozygotes, whereas in the infected animals, the genotypic distribution was the opposite. An association analysis between the identified polymorphism and production traits-including somatic cell count, as well as lactose, protein, and casein content and yield as indicators of subclinical mastitis occurrence-was performed on the group II cows (166 Polish Holstein-Friesian dairy cows). Unfortunately, due to the low number of AB animals, no relationship was demonstrated between genotype in the second exon and the health status of cows. Additionally, the difference in the percentage of SLAMF7-targeted DNA methylation between the groups of animals was not significant, with an average of ∼66 to 68%.

Quasinormal mode solvers for resonators with dispersive materials.

Optical resonators are widely used in modern photonics. Their spectral response and temporal dynamics are fundamentally driven by their natural resonances, the so-called quasinormal modes (QNMs), with complex frequencies. For optical resonators made of dispersive materials, the QNM computation requires solving a nonlinear eigenvalue problem. This raises a difficulty that is only scarcely documented in the literature. We review our recent efforts for implementing efficient and accurate QNM solvers for computing and normalizing the QNMs of micro- and nanoresonators made of highly dispersive materials. We benchmark several methods for three geometries, a two-dimensional plasmonic crystal, a two-dimensional metal grating, and a three-dimensional nanopatch antenna on a metal substrate, with the perspective to elaborate standards for the computation of resonance modes.

Design of metallic nanoparticle gratings for filtering properties in the visible spectrum.

Plasmonic resonances in metallic nanoparticles are exploited to create efficient optical filtering functions. A finite element method is used to model metallic nanoparticle gratings. The accuracy of this method is shown by comparing numerical results with measurements on a two-dimensional grating of gold nanocylinders with an elliptic cross section. A parametric analysis is then performed in order to design efficient filters with polarization dependent properties together with high transparency over the visible range. The behavior of nanoparticle gratings is also modeled using the Maxwell-Garnett homogenization theory and analyzed by comparison with the diffraction of a single nanoparticle. The proposed structures are intended to be included in optical systems that could find innovative applications.

Pedigrees as a source of information in mtDNA studies of dogs and horses.

The goal of this study was to demonstrate the usefulness of pedigree data in studies of mitochondrial DNA diversity in dogs and horses. Pedigree information allows for precisely choosing animals with distinct haplotypes for analysis, makes it possible to find rare haplotypes present exclusively in single individuals and helps to evaluate haplotype frequencies at the present and in the past. Estimating founder contributions to gene pools enables evaluating the parts of gene pools observed with the help of mtDNA analysis. An important aspect is also the financial benefits: using pedigree data, researchers can save a significant amount of time and money needed for sample collection and laboratory analysis.

A limited sampling strategy for estimating mycophenolic acid area under the curve in adult heart transplant patients treated with concomitant cyclosporine.

OBJECTIVE: Heart transplantation studies have shown a relationship between the mycophenolic acid area under the curve (AUC) 0-12 h (MPA AUC(0-12h)) values and risk of acute rejection episodes and fewer side-effects in patient receiving cyclosporine during the first year post-transplant. However, measurement of full AUC is costly and time consuming and in this case it is an impractical approach to drug monitoring. Therefore, the authors describe a limited sampling strategy to estimate the MPA AUC(0-12h) value in adult heart transplant recipients. METHODS: Ninety MPA pharmacokinetic (PK) profiles were studied. The samples were collected immediately before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 9, 12 h after the morning dose of mycophenolate mofetil (MMF) following an overnight fast. PK profiles were determined at 6-8 weeks, 6, 12 months and more than 1 year after transplantation. Using stepwise multiple linear regression analysis a sampling strategy from 60 of PK profiles was obtained and next the bias and precision of the model were evaluated in another 30 PK profiles. RESULTS: The three-point model using C(0.5h), C(1h), C(2h) was found to be superior to all other models tested (r(2) = 0.841). The regression equation for AUC estimation which gave the best fit to this model is: 9.69 + 0.63C(0.5) + 0.61C(1) + 2.20C(2). Using that model 63 of the 90 (70%) full AUC values were estimated within 15% of their actual value. For the best-fit model, the mean prediction error was 3.2%, with 95% confidence intervals for prediction error to range from -42.2% to 40.3%. All other models which use one, two or three time-points over the first 2 h are poorer predictors of the full AUC than the model above. CONCLUSION: The proposed three time-point equation to estimate AUC will be helpful in optimizing immunosuppressive therapy in heart transplantation.

The weight of pharmacokinetic parameters for mycophenolic acid in prediction of rejection outcome: the receiver operating characteristic curve analysis.

Often the clinical researcher is confronted with the question of how accurate a particular laboratory test is to identify disease. To confirm the ability of pharmacokinetic (PK) parameters to discriminate between patients with or without acute rejection after kidney transplantation, an analysis of receiver operating characteristic (ROC) curves was performed in 51 adult patients, among whom nearly 50% experienced biopsy-proven acute rejection episodes during the first 90 days posttransplant. All patients received cyclosporine or tacrolimus, prednisone, and mycophenolate mofetil (MMF). The following PK variables were determined for mycophenolic acid, an active metabolite of MMF: predose (C(0)), maximum concentration (C(max)), and area under the concentration-time curve (AUC(0-12h)). ROC plots of sensitivity versus 1-specificity were generated to determine whether a particular PK parameter could discriminate renal transplant recipients with an acute rejection from those who experienced no rejection. Area under the ROC curves and the 95% confidence interval limits were calculated using the method of Hanley and McNeil. The C(0) and C(max) were less predictive values for acute rejection than AUC(0-12h). The AUC parameter appeared the most effective to discriminate an acute rejection episode during MMF therapy. This study indicated the utility of ROC curve analysis to select PK parameters to predict acute rejection episodes.

International Equine Gene Mapping Workshop Report: a comprehensive linkage map constructed with data from new markers and by merging four mapping resources.

A comprehensive male linkage map was generated by adding 359 new, informative microsatellites to the International Equine Gene Map half-sibling reference families and by combining genotype data from three independent mapping resources: a full sibling family created at the Animal Health Trust in Newmarket, United Kingdom, eight half-sibling families from Sweden and two half-sibling families from the University of California, Davis. Because the combined data were derived primarily from half-sibling families, only autosomal markers were analyzed. The map was constructed from a total of 766 markers distributed on the 31 equine chromosomes. It has a higher marker density than that of previously reported maps, with 626 markers linearly ordered and 140 other markers assigned to a chromosomal region. Fifty-nine markers (7%) failed to meet the criteria for statistical evidence of linkage and remain unassigned. The map spans 3,740 cM with an average distance of 6.3 cM between markers. Fifty-five percent of the intervals are < or = 5 cM and only 3% > or = 20 cM. The present map demonstrates the cohesiveness of the different data sets and provides a single resource for genome scan analyses and integration with the radiation hybrid map.

Analogies between optical propagation and heat diffusion: applications to microcavities, gratings and cloaks.

A new analogy between optical propagation and heat diffusion in heterogeneous anisotropic media has been proposed recently by three of the present authors. A detailed derivation of this unconventional correspondence is presented and developed. In time harmonic regime, all thermal parameters are related to optical ones in artificial metallic media, thus making possible to use numerical codes developed for optics. Then, the optical admittance formalism is extended to heat conduction in multilayered structures. The concepts of planar microcavities, diffraction gratings and planar transformation optics for heat conduction are addressed. Results and limitations of the analogy are emphasized.

Morpho butterflies wings color modeled with lamellar grating theory.

We describe an approach for converting reflection coefficients of any structure into colors, taking into account human color perception. This procedure is applied to the study of the colors reflected by Morpho rhetenor butterflies wings. The scales of these wings have a tree-like periodic structure which is modeled with the help of a rigorous lamellar grating electromagnetic theory. In this way, we are able to determine the colors reflected by the wing under various illumination conditions.

Anomalous refractive properties of photonic crystals

We describe methods of investigating the behavior of photonic crystals. Our approach establishes a link between the dispersion relation of the Bloch modes for an infinite crystal (which describes the intrinsic properties of the photonic crystal in the absence of an incident field) and the diffraction problem of a grating (finite photonic crystal) illuminated by an incident field. We point out the relationship between the translation operator of the first problem and the transfer matrix of the second. The eigenvalues of the transfer matrix contain information about the dispersion relation. This approach enables us to answer questions such as When does ultrarefraction occur? Can the photonic crystal simulate a homogeneous and isotropic material with low effective index? This approach also enables us to determine suitable parameters to obtain ultrarefractive or negative refraction properties and to design optical devices such as highly dispersive microprisms and ultrarefractive microlenses. Rigorous computations add a quantitative aspect and demonstrate the relevance of our approach.

Photonic crystal lens: from negative refraction and negative index to negative permittivity and permeability.

We consider a dielectric photonic crystal made of cylindrical holes in a high index matrix. We show that a given finite size photonic crystal can mimic a homogeneous material whose permittivity and permeability are negative. We pay attention to the limitation of the homogeneous medium model and the vital role of the truncation of the crystal.

Comparison of mycophenolic acid pharmacokinetic parameters in kidney transplant patients within the first 3 months post-transplant.

OBJECTIVE: The aim of this study was to investigate the effect of time on pharmacokinetic (PK) parameters of mycophenolic acid (MPA) in the early post-transplant period in kidney recipients. MPA is the active metabolite of mycophenolate mofetil (MMF), which was introduced into clinical practice ten years ago. METHOD: Mycophenolate mofetil was co-administered with cyclosporin (CsA) in a subgroup of 23 patients and with tacrolimus (Tac) in a subgroup of 10 patients. MPA plasma concentration profiles were measured by a validated high performance liquid chromatography method 1 week, 2 and 3 months after transplantation. RESULTS: Despite a comparable MMF dose, a large inter-patient variability in both MPA area under the curve (AUC) from 0 to 12 h (range 10.03-135.4 microg h/mL) and in predose concentrations (0.31-6.09 microg/mL) was observed. Patients with AUC > 35 microg h/mL showed better (P < 0.1) renal function than patients with AUC < 20 microg h/mL (mean creatinine concentration 1.48 +/- 0.12 vs. 3.35 +/- 0.4 mg/dL respectively). The total MPA trough and AUC did not correlate with biochemical parameters: leucocyte cell count and haematocrit. A higher trough level of the metabolite MPA glucuronide (MPAG) in the 1 week after transplantation was found when compared with the 3-month level (mean 150.1 +/- 146.7; range 17.1 to 560 vs. 75.8 +/- 40.0; range 27.3 to 174.2 microg/mL). The concentration of MPA, and MPA AUC values were significantly lower in patients receiving MMF and CsA than those receiving MMF and Tac during all three periods studied (P < 0.02). The influence of C(0) and MPA AUC values on the risk of graft rejection was investigated using receiver operating characteristic (ROC) curve analysis. The area under the ROC curve for AUC was 0.847, whereas that of C(0) was 0.632. CONCLUSIONS: The MPA AUC(0-12h) appeared to be the more effective PK parameter for predicting acute rejection. We recommend that routine MPA and MPAG therapeutic drug level monitoring should be an important part of MMF therapy.

The second generation of the International Equine Gene Mapping Workshop half-sibling linkage map.

A low-density, male-based linkage map was constructed as one of the objectives of the International Equine Gene Mapping Workshop. Here we report the second generation map based on testing 503 half-sibling offspring from 13 sire families for 344 informative markers using the CRIMAP program. The multipoint linkage analysis localized 310 markers (90%) with 257 markers being linearly ordered. The map included 34 linkage groups representing all 31 autosomes and spanning 2262 cM with an average interval between loci of 10.1 cM. This map is a milestone in that it is the first map with linkage groups assigned to each of the 31 automosomes and a single linkage group to all but three chromosomes.