International cohort study of 73 anti-Ku-positive patients: association of p70/p80 anti-Ku antibodies with joint/bone features and differentiation of disease populations by using principal-components analysis

Introduction

An international cohort study of 73 anti-Ku-positive patients with different connective tissue diseases was conducted to differentiate the anti-Ku-positive populations of patients based on their autoantibody profile and clinical signs/symptoms and to establish possible correlations between antibodies against Ku p70 and Ku p80 with autoimmune diseases.

Methods

Sera of anti-Ku-positive patients were collected from six European centers and were all secondarily tested (in the reference center); 73 were confirmed as positive. Anti-Ku antibodies were detected with counter-immunoelectrophoresis (CIE), line immunoassay (LIA), and immunoblot analyses. All clinical and laboratory data were follow-up cumulative data, except for anti-Ku antibodies. Statistical analyses were performed by using R (V 2.12.1). The Fisher Exact test was used to evaluate the association between anti-Ku antibodies and diagnosis, gender, clinical signs, and other observed antibodies. The P values were adjusted for multiple testing. Separation of disease populations based on the presence of antibodies and clinical signs was investigated by principal-components analysis, which was performed by using thr// R's prcomp function with standard parameters.

Results

A 16% higher prevalence of anti-Ku p70 was found over anti-Ku p80 antibodies. In 41 (57%) patients, a combination of both was detected. Five (7%) patients, who were CIE and/or LIA anti-Ku positive, were negative for both subsets, as detected with the immunoblot; 31% of the patients had undifferentiated connective tissue disease (UCTD); 29% had systemic sclerosis (SSc); 18% had systemic lupus erythematosus (SLE); 11% had rheumatoid arthritis; 7% had polymyositis; and 3% had Sjögren syndrome.

Conclusions

A significant positive association was found between female patients with anti-Ku p70 and joint/bone features, and a significant negative association was found between female patients with anti-Ku p80 only and joint/bone features (P = 0.05, respectively). By using the first and the third components of the principal-component analysis (PCA) with 29 parameters evaluated, we observed that the anti-Ku-positive population of UCTD patients had overlapping parameters, especially with SLE, as opposed to SSc, which could be helpful in delineating UCTD patients.     

Naturally occurring structural isomers in serum IgA1 o-glycosylation

IgA is the most abundantly produced antibody and plays an important role in the mucosal immune system. Human IgA is represented by two isotypes, IgA1 and IgA2. The major structural difference between these two subclasses is the presence of nine potential sites of O-glycosylation in the hinge region between the first and second constant region domains of the heavy chain. Thr(225), Thr(228), Ser(230), Ser(232) and Thr(236) have been identified as the predominant sites of O-glycan attachment. The range and distribution of O-glycan chains at each site within the context of adjacent sites in this clustered region create a complex heterogeneity of surface epitopes that is incompletely defined. We previously described the analysis of IgA1 O-glycan heterogeneity by use of high resolution LC-MS and electron capture dissociation tandem MS to unambiguously localize all amino acid attachment sites in IgA1 (Ale) myeloma protein. Here, we report the identification and elucidation of IgA1 O-glycopeptide structural isomers that occur based on amino acid position of the attached glycans (positional isomers) and the structure of the O-glycan chains at individual sites (glycan isomers). These isomers are present in a model IgA1 (Mce1) myeloma protein and occur naturally in normal human serum IgA1. Variable O-glycan chains attached to Ser(230), Thr(233) or Thr(236) produce the predominant positional isomers, including O-glycans composed of a single GalNAc residue. These findings represent the first definitive identification of structural isomeric IgA1 O-glycoforms, define the single-site heterogeneity for all O-glycan sites in a single sample, and have implications for defining epitopes based on clustered O-glycan variability.     

Molecular mechanism for the selective impairment of cancer mitochondrial function by a mitochondrially targeted vitamin E analogue

The effects of α-tocopheryl succinate (α-TOS), α-tocopheryl acetyl ether (α-TEA) and triphenylphosphonium-tagged vitamin E succinate (mitochondrially targeted vitamin E succinate; MitoVES) on energy-related mitochondrial functions were determined in mitochondria isolated from AS-30D hepatoma and rat liver, bovine heart sub-mitochondrial particles (SMPs), and in rodent and human carcinoma cell lines and rat hepatocytes. In isolated mitochondria, MitoVES stimulated basal respiration and ATP hydrolysis, but inhibited net state 3 (ADP-stimulated) respiration and Ca(2+) uptake, by collapsing the membrane potential at low doses (1-10μM). Uncoupled mitochondrial respiration and basal respiration of SMPs were inhibited by the three drugs at concentrations at least one order of magnitude higher and with different efficacy: MitoVES>α-TEA>α-TOS. At high doses (>10μM), the respiratory complex II (CII) was the most sensitive MitoVES target. Acting as an uncoupler at low doses, this agent stimulated total O(2) uptake, collapsed ?ψ(m), inhibited oxidative phosphorylation and induced ATP depletion in rodent and human cancer cells more potently than in normal rat hepatocytes. These findings revealed that in situ tumor mitochondria are preferred targets of the drug, indicating its clinical relevance.     

Characterization of Stowaway MITEs in pea (Pisum sativum L.) and identification of their potential master elements.

We have investigated miniature inverted-repeat transposable elements (MITEs) of the Stowaway family and corresponding Mariner-like master elements that could potentially facilitate their mobilization in the genome of the garden pea (Pisum sativum L.). The population of pea Stowaway MITEs consists of 103-104 copies dispersed in the genome. Judging from a sequence analysis of 17 isolated Stowaway elements and their flanking genomic regions, the elements are relatively uniform in size and sequence and occur in the vicinity of genes as well as within repetitive sequences. Insertional polymorphism of several elements was detected among various Pisum accessions, suggesting they were still transpositionally active during diversification of these taxa. The identification of several Mariner-like elements (MLEs) harboring intact open reading frames, capable of encoding a transposase, further supports a recent mobilization of the Stowaway elements. Using transposase-coding sequences as a hybridization probe, we estimated that there are about 50 MLE sequences in the pea genome. Among the 5 elements sequenced, 3 distinct subfamilies showing mutual similarities within their transposase-coding regions, but otherwise diverged in sequence, were distinguished and designated as Psmar-1 to Psmar-3. The terminal inverted repeats (TIRs) of these MLE subfamilies differed in their homology to the TIRs of Stowaway MITEs. The homlogy ranged from 9 bp in Psmar-3 to 30 bp in Psmar-1, which corresponds to the complete Stowaway TIR sequence. Based on this feature, the Psmar-1 elements are believed to be the most likely candidates for the master elements of the Stowaway MITEs in pea.     

How universal are reserve design rules? A test using butterflies and their life history traits

We used butterfly species lists available for a set of 125 Czech Republic National Nature Reserves and Monuments, the highest small‐sized conservation category in the country encompassing practically all biotope types existing in central Europe, to test the validity of generally agreed “reserve design rules” using multivariate ordination analyses. Further, we used ordination analysis of butterfly life history traits to seek for biological mechanisms responsible for butterfly community responses to essentially geometric reserves characteristics. Reserve area, relative perimeter, within reserve habitat heterogeneity, and surrounding landscape compositional and configurational heterogeneity all affected the composition of butterfly assemblages after controlling for effects of geographical position and prevailing biotope type. Species inclining towards large reserves displayed low mobility and high local population density, probably because they require large habitat areas to maintain self‐sustaining populations; such species tend to have restricted distribution in the country and threatened status. Reserves with relatively long boundaries hosted species with high mobility, broad trophic range and long adult period; faunas of such reserves contain high proportions of widespread generalists. Species with narrow trophic ranges inclined towards reserves containing diverse habitats, probably due to requirements for high floristic diversity. Species with short adult flight, low generations number and overwintering in early stages inclined towards reserves situated amidst diverse landscapes, perhaps because such species require finely‐grained mosaics for metapopulation dynamics. Commonly agreed reserve design rules thus hold for Central European butterflies, but different design characteristics are important for individual species, depending on their life histories.     

Hybrid Sterility Locus on Chromosome X Controls Meiotic Recombination Rate in Mouse

Meiotic recombination safeguards proper segregation of homologous chromosomes into gametes, affects genetic variation within species, and contributes to meiotic chromosome recognition, pairing and synapsis. The Prdm9 gene has a dual role, it controls meiotic recombination by determining the genomic position of crossover hotspots and, in infertile hybrids of house mouse subspecies Mus m. musculus (Mmm) and Mus m. domesticus (Mmd), it further functions as the major hybrid sterility gene. In the latter role Prdm9 interacts with the hybrid sterility X 2 (Hstx2) genomic locus on Chromosome X (Chr X) by a still unknown mechanism. Here we investigated the meiotic recombination rate at the genome-wide level and its possible relation to hybrid sterility. Using immunofluorescence microscopy we quantified the foci of MLH1 DNA mismatch repair protein, the cytological counterparts of reciprocal crossovers, in a panel of inter-subspecific chromosome substitution strains. Two autosomes, Chr 7 and Chr 11, significantly modified the meiotic recombination rate, yet the strongest modifier, designated meiotic recombination 1, Meir1, emerged in the 4.7 Mb Hstx2 genomic locus on Chr X. The male-limited transgressive effect of Meir1 on recombination rate parallels the male-limited transgressive role of Hstx2 in hybrid male sterility. Thus, both genetic factors, the Prdm9 gene and the Hstx2/Meir1 genomic locus, indicate a link between meiotic recombination and hybrid sterility. A strong female-specific modifier of meiotic recombination rate with the effect opposite to Meir1 was localized on Chr X, distally to Meir1. Mapping Meir1 to a narrow candidate interval on Chr X is an important first step towards positional cloning of the respective gene(s) responsible for variation in the global recombination rate between closely related mouse subspecies.     

Novel immunohistochemical markers for the differentiation of lobular and ductal invasive breast carcinomas

AIMS. Invasive ductal and lobular carcinomas are the most common histological types of breast cancer. The loss of E-cadherin expression has been suggested to be the most reliable marker for invasive lobular carcinoma. The aim of our study was to identify the diagnostic usefulness of novel markers in the differentiation of these tumor types. METHODS. We examined tissue microarrays (TMA) which were constructed from surgical specimens of 119 breast cancer patients. TMA consisted of 80 ductal carcinomas, 29 lobular carcinomas and special type cancers. TMA sections were stained using standard immunohistochemical methods. Monoclonal mouse antibodies against E-cadherin, cytokeratin 5/6 and 17, and polyclonal mouse antibodies against EMP1, DDR1, PRKCI and DVL1 were used. RESULTS. E-cadherin was absent in 93.3% of lobular tumors compared with only 15 % of ductal tumors (p<0.0001). EMP1 and DVL1 were overexpressed in lobular tumors (93.1% and 96.5%, respectively), whereas PRKCI and DDR1 were positive in ductal cancers (90% and 96.2%, respectively). Reduced expression or absence of both cytokeratins 5/6 and 17 was found in both tumor tissues in comparison to normal terminal duct lobular units (p<0.0001). CONCLUSIONS. Apart from the well-established marker, E-cadherin, proteins examined on TMA slides by immunohistochemistry (EMP1, DVL1, DDR1, PRKCI) may represent novel tissue markers helpful in the differentiation of ductal and lobular breast cancers. Further studies with larger sets of patients are desirable, to verify the complete immunohistochemical profiles of various histological types of breast cancer and determine the prognostic and predictive significance of novel markers.     

Early fracture of a plasma cup ceramic liner: a case report and surface analysis

Background: Ceramic surfaces offer excellent tribological properties and for this reason are frequently used in younger patients with osteoarthritis of the hip. However, they may fracture easily owing to low tolerance to tensile and impact stresses in particular. We report a case of early fracture of a currently available ceramic liner in a 44-year-old woman with revision total hip arthroplasty. Methods and Results: Scanning electron microscopy and macroscopic fractographic examination were done to elucidate the cause of failure. These showed the fracture started most probably at the inner surface of the cup. Several mechanisms of fracture initiation are discussed in the paper. Conclusion: This is the first report on early fracture of the Plasma cup ceramic liner in white man. The fracture occurred intraoperatively or early postoperatively while the diagnosis was determined much later despite the patient had experienced sensations of subluxations long time before.