Analysis of immunoglobulin light chain rearrangements in the salivary gland and blood of a patient with Sjögren's syndrome

Patients with Sjögren's syndrome (SS) have characteristic lymphocytic infiltrates of the salivary glands. To determine whether the B cells accumulating in the salivary glands of SS patients represent a distinct population and to delineate their potential immunopathologic impact, individual B cells obtained from the parotid gland and from the peripheral blood were analyzed for immunglobulin light chain gene rearrangements by PCR amplification of genomic DNA. The productive immunglobulin light chain repertoire in the parotid gland of the SS patient was found to be restricted, showing a preferential usage of particular variable lambda chain genes (Vλ2E) and variable kappa chain genes (VκA27). Moreover, clonally related V_L chain rearrangements were identified; namely, VκA27–Jκ5 and VκA19–Jκ2 in the parotid gland, and Vλ1C–Jλ3 in the parotid gland and the peripheral blood. Vκ and Vλ rearrangements from the parotid gland exhibited a significantly elevated mutational frequency compared with those from the peripheral blood (P < 0.001). Mutational analysis revealed a pattern of somatic hypermutation similar to that found in normal donors, and a comparable impact of selection of mutated rearrangements in both the peripheral blood and the parotid gland. These data indicate that there is biased usage of V_L chain genes caused by selection and clonal expansion of B cells expressing particular V_L genes. In addition, the data document an accumulation of B cells bearing mutated V_L gene rearrangements within the parotid gland of the SS patient. These results suggest a role of antigen-activated and selected B cells in the local autoimmune process in SS.     

Behavioral assessment of the ability of intracerebral embryonic neural tissue grafts to ameliorate the effects of brain damage in marmosets

The transplantation of neuronal tissue into the brains of patients with Parkinson's disease is already being assessed as an experimental treatment for the symptoms of this disease, and the possibility of using similar graft tissue to ameliorate the symptoms of other neurodegenerative diseases is being considered. In this context, a small number of transplant experiments have been carried out in monkeys with lesions of the central dopamine and cholinergic systems. These experiments make it possible to determine the optimum methods of transplantation in an animal whose brain is structurally more closely related to the human than that of the rat and to assess the behavioral consequences of transplantation on symptoms that either resemble very closely the symptoms seen in patients, or are of a complex cognitive nature and are therefore more difficult to measure in the rat. It is intended that these experiments will contribute to the development of better treatments for the neurodegenerative diseases, either by the use of transplantation as a clinical treatment, or by contributing to a better understanding of the mechanisms that normally maintain neuronal function and that fail in these diseases.     

Gonorrhea modeling: a comparison of control methods

A population dynamics model for a heterogeneous population is used to compare the effectiveness of six prevention methods for gonorrhea involving population screening and contact tracing of selected groups. The population is subdivided according to sex, sexual activity, and symptomatic or asymptomatic infection. For this model contact tracing of certain groups is more effective than general population screening.     

Balancing the length of the distal tip by septins is key for stability and signalling function of primary cilia

Primary cilia are antenna‐like organelles required for signalling transduction. How cilia structure is mechanistically maintained at steady‐state to promote signalling is largely unknown. Here, we define that mammalian primary cilia axonemes are formed by proximal segment (PS) and distal segment (DS) delineated by tubulin polyglutamylation‐rich and ‐poor regions, respectively. The analysis of proximal/distal segmentation indicated that perturbations leading to cilia over‐elongation influenced PS or DS length with a different impact on cilia behaviour. We identified septins as novel repressors of DS growth. We show that septins control the localisation of MKS3 and CEP290 required for a functional transition zone (TZ), and the cilia tip accumulation of the microtubule‐capping kinesin KIF7, a cilia‐growth inhibitor. Live‐cell imaging and analysis of sonic‐hedgehog (SHH) signalling activation established that DS over‐extension increased cilia ectocytosis events and decreased SHH activation. Our data underlines the importance of understanding cilia segmentation for length control and cilia‐dependent signalling.     

1H NMR conformational study on n-terminal nonapeptide sequences of HIV-1 Tat protein: a contribution to structure–activity relationships

On the basis of our recent results, the N-terminal sequence of HIV-1 Tat protein as a natural competitive inhibitor of dipeptidyl peptidase IV (DP IV) is supposed to interact directly with the active site of DP IV hence mediating its immunosuppressive effects via specific DP IV interactions. Of special interest is the finding that amino acid substitutions of the Tat(1–9) peptide (MDPVDPNIE) in position 5 with S-isoleucine and in position 6 with S-leucine led to peptides with strongly reduced inhibitory activity suggesting differences in the solution conformation of the three analogues. Therefore, ¹H NMR techniques in conjunction with molecular modelling have been used here to determine the solution structure of Tat(1–9), I⁵-Tat(1–9) and L⁶-Tat(1–9) and to examine the influence of amino acid exchanges on structural features of these peptides. The defined structures revealed differences in the conformations what might be the reason for different interactions of these Tat(1–9) analogues with certain amino acids of the active site of DP IV. © 1998 European Peptide Society and John Wiley & Sons, Ltd.     

Habitat differences affect life history tactics of a pulsed resource consumer,the edible dormouse (<Emphasis Type="Italic">Glis glis</Emphasis>)

We studied flexibility of life history tactics, in terms of habitat-dependent survival and reproduction, in a pulsed resource consumer, the edible dormouse (Glis glis). We compared capture–mark–recapture data from three subpopulations of dormice: one in a homogeneous beech forest (Forest), and two in patches of woodland (Grove/Hedge), with more constant but less energy-rich food availability (e.g., fleshy fruits), over a period of 5 years. The general seasonal pattern of hibernation and reproduction was similar in all three subpopulations. Juveniles were born in only 3 out of 5 years at all study sites, which was paralleled by the occurrence of strong seed production in beech. Reproductive output (number of juveniles/female) was lower at the two sites with low seed tree abundance (Grove: 1.3; Hedge: 2.0) than in the Forest (4.4). Yearly survival probability of adults was significantly lower in the Forest (0.57, CI = 0.42–0.70) than in the areas Grove and Hedge (0.83, CI = 0.70–0.91). Despite their shortened lifespan, estimated lifetime reproductive success of females in the Forest was higher (6.2 young) than in the areas Grove/Hedge (4.8 young). Together, these data indicate that, in more constant habitats (Grove/Hedge), lower reproductive investment was associated with increased longevity. However, dormice apparently maximise lifetime reproductive success by a ‘sit tight’ strategy that synchronises reproduction with energy rich seed pulses in deciduous forests. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Characterization of advanced glycation end products: mass changes in correlation to side chain modifications

Advanced glycation end products (AGEs) that arise from the reaction of sugars with protein side chains are supposed to be involved in the pathogenesis of several diseases; therefore, the effects of AGEs on cells are the objective of numerous investigations. Because AGE modifications are an extremely heterogeneous group of side chain modifications, the exact characterization of an AGE-modified protein is impossible. To gain a deeper understanding about AGE formation kinetics and structures, AGEs can be characterized with respect to the degree of modification, specific side chain modifications, absorbance and fluorescence characteristics, and changes in the protein structure and molecular weight. For this study, human serum albumin (HSA)-AGEs derived from different concentrations of glucose, methyl glyoxal, and glyoxylic acid were used. The molecular mass of the obtained AGEs was determined using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The mass data were compared with earlier results concerning the degree of lysine and arginine side chain modifications and AGE-specific fluorescence and absorbance data. The molecular masses were found to gradually increase with increasing concentrations of the individual modifier without reaching a plateau. The mass increase correlates very well with the AGE-specific absorbance at 360 nm and with the degree of side chain modifications. The mass spectrometric data prove, for the first time, that an increasing absorbance at 360 nm is directly correlated to a mass increase during the AGE formation process.     

Two analytical methods to study the interaction of AGEs with cell surface proteins

Advanced glycation end products (AGEs) are sugar-modified proteins that are known to appear in vivo and are suspected to be involved in the pathogenesis of several diseases. Although different cellular responses to AGEs can be measured in cell culture studies, knowledge about the nature of AGE-binding and their cell surface receptors is poor. In the present paper a method for the purification of AGE-binding proteins from membrane fractions derived from different rat organs as well as a method for assaying the binding of fluorescein labelled AGEs to the surface of cells of different cell lines are described. The presence of more than 10 proteins interacting with AGEs could be shown in membrane fractions obtained from rat organs. Additionally, binding of AGE-modified BSA to different cells could be shown using fluorescence-labelled ligands in a flow cytometric approach. The presented methods provide an option to isolate AGE-interacting proteins which is a precondition for the identification of these proteins. Furthermore, the measurement of AGE-binding to cell surfaces bears the potential to gain a deeper understanding about the nature of AGE-binding to cell surface proteins and might be applied as a preliminary test before performing cell culture studies about AGE effects.     

A multi-gene phylogeny of aquiline eagles (Aves: Accipitriformes) reveals extensive paraphyly at the genus level

The phylogeny of the tribe Aquilini (eagles with fully feathered tarsi) was investigated using 4.2 kb of DNA sequence of one mitochondrial (cyt b) and three nuclear loci (RAG-1 coding region, LDH intron 3, and adenylate-kinase intron 5). Phylogenetic signal was highly congruent and complementary between mtDNA and nuclear genes. In addition to single-nucleotide variation, shared deletions in nuclear introns supported one basal and two peripheral clades within the Aquilini. Monophyly of the Aquilini relative to other birds of prey was confirmed. However, all polytypic genera within the tribe, Spizaetus, Aquila, Hieraaetus, turned out to be non-monophyletic. Old World Spizaetus and Stephanoaetus together appear to be the sister group of the rest of the Aquilini. Spizastur melanoleucus and Oroaetus isidori are nested among the New World Spizaetus species and should be merged with that genus. The Old World 'Spizaetus' species should be assigned to the genus Nisaetus (Hodgson, 1836). The sister species of the two spotted eagles (Aquila clanga and Aquila pomarina) is the African Long-crested Eagle (Lophaetus occipitalis). Hieraaetus fasciatus/spilogaster are closest to Aquila verreauxii and should be merged with that genus. Wahlberg's Eagle H. wahlbergi, formerly placed in Aquila, is part of a clade including three small Hieraaetus species (pennatus, ayresii, and morphnoides). The Martial Eagle (Polemaetus bellicosus) is the sister species of the Aquila/Hieraaetus/Lophaetus clade. Basal relationships within this clade remained unresolved. Parsimony reconstruction of the evolution of plumage pattern within Aquilini suggests that: (1) transverse barring of parts of the body plumage was lost in the Palearctic Aquila-Hieraaetus clade, (2) pale underparts in adult plumage evolved three times independently, and (3) dimorphic adult plumage is a derived character of the small-bodied Hieraaetus clade.