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Marked Similarities (marked + similarity)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	33%

Selected Abstracts

Molecular diversity of HLA-A*19 group of alleles in south Indian population

INTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2006
V. Vettriselvi
Summary To determine the genetic diversity of the human leucocyte antigen (HLA)-A*19 group of alleles in the south Indian Tamil population, we studied 100 random healthy unrelated individuals. The frequency of HLA-A*19 was 37% with A*33 (45.9%), A*32 (29.7%), A*31 (16.2%), A*30 (5.4%), A*29 (2.7%) and A*74 (0%). The frequency distribution of the HLA-A*19 alleles was distinct and revealed marked similarities and variations with other populations [source]

Degenerative and regenerative processes involved in midgut pseudotumor formation in the stick insect (Carausius morosus)

JOURNAL OF MORPHOLOGY, Issue 12 2009
Paul Hoffmann
Abstract Spontaneous and experimentally induced pseudotumor formation in Carausius morosus impairs the midgut tissue homeostasis. Spontaneous pseudotumor formation begins by the break down of a single or a small group of columnar cells (CCs) and is followed by the degeneration of neighboring CCs. There are not only marked similarities but also decisive differences between normal dying CCs in healthy specimens and the degeneration of CCs leading to pseudotumors: in both cases, the apical cell parts with the nucleus are extruded into the midgut lumen, but only during of pseudotumor formation an "amorphous substance" originates from the basal parts of the CCs. Hemocytes are attracted to this substance and form a nodule-like aggregation, which is responsible for the phenotype of pseudotumors. Pseudotumor infestation has also an impact on the midgut nidi, which consist of an intestinal stem cell and several CC progenitor cells. In healthy specimens only one progenitor cell per nidus differentiates at a time, but, several to all progenitor cells differentiate simultaneously in pseudotumor-infested specimens. Extirpation of the ingluvial ganglion in healthy specimens results in an immediate onset of pseudotumor formation and a dramatic acceleration of pseudotumor growth. Importantly, the ultrastructural characteristics of spontaneous and experimentally induced pseudotumors are identical. This supports the idea that the stomatogastric nervous system plays an integral role in the maintenance of midgut tissue homeostasis. J. Morphol., 2009. © 2009 Wiley-Liss, Inc. [source]

T-cell receptor repertoire in IgA nephropathy renal biopsies

NEPHROLOGY, Issue 2002
John F Knight
SUMMARY: Renal biopsies from patients with IgA nephropathy (IgAN) were studied to determine whether the presence of ,, and ,, T cells is correlated with disease progression in IgAN. The ,, and ,, T-cell receptor (TCR) repertoire was further analysed in these renal biopsies. Immunohistochemical staining using mAb (TCR, and TCR,) and molecular studies using reverse transcription,polymerase chain reaction (RT-PCR) with primers specific for TCR families were undertaken. CDR3 length spectratyping and sequencing of TCR chains were used to analyse the diversity of the CDR3 region of these receptors. It was demonstrated that the presence of ,, T cells is associated with progressive IgAN while ,, T cells are found in both stable and progressive disease. Analysis of the TCR variable (V), repertoire showed the preferential use of V,8 with marked similarities in the CDR3 region by some renal infiltrating T cells in the kidney of some IgAN patients, although T cells infiltrating the renal interstitium of patients with IgAN express heterogeneous T cell receptors. The data from analysis of ,, T-cell repertoire showed that ,, T cells infiltrating the kidneys of IgAN patients use a restricted subset of ,, T cells with a feature of recurrent junctional amino acid motifs in V,1 T cells. The results suggest that both ,, and ,, T cells are involved in the progression of IgAN to renal failure and also that there is clonal expansion of individual ,, or ,, T cells in the kidneys of some IgAN patients. The conserved amino acid in the TCR CDR3 region of V,8 and the feature of recurrent junctional amino acid motifs in V,1 T cells may indicate antigen-driven selection. [source]

T-cell receptor repertoire in IgA nephropathy renal biopsies

NEPHROLOGY, Issue 2002
John F KNIGHT
SUMMARY: Renal biopsies from patients with IgA nephropathy (IgAN) were studied to determine whether the presence of ,, and ,, T cells is correlated with disease progression in IgAN. the ,, and ,, T-cell receptor (TCR) repertoire was further analysed in these renal biopsies. Immunohistochemical staining using mAb (TCR, and TCR,) and molecular studies using reverse transcription-polymerase chain reaction (RT-PCR) with primers specific for TCR families were undertaken. CDR3 length spectratyping and sequencing of TCR chains were used to analyse the diversity of the CDR3 region of these receptors. It was demonstrated that the presence of ,, T cells is associated with progressive IgAN while ,, T cells are found in both stable and progressive disease. Analysis of the TCR variable (V), repertoire showed the preferential use of V,8 with marked similarities in the CDR3 region by some renal infiltrating T cells in the kidney of some IgAN patients, although T cells infiltrating the renal interstitium of patients with IgAN express heterogeneous T cell receptors. the data from analysis of ,, T-cell repertoire showed that ,, T cells infiltrating the kidneys of IgAN patients use a restricted subset of ,, T cells with a feature of recurrent junctional amino acid motifs in V,1 T cells. the results suggest that both ,, and ,, T cells are involved in the progression of IgAN to renal failure and also that there is clonal expansion of individual ,, or ,, T cells in the kidneys of some IgAN patients. the conserved amino acid in the TCR CDR3 region of V,8 and the feature of recurrent junctional amino acid motifs in V,1 T cells may indicate antigen-driven selection. [source]

Bacterial diversity in the breadcrumb sponge Halichondria panicea (Pallas)

FEMS MICROBIOLOGY ECOLOGY, Issue 1 2006
Antje Wichels
Abstract The aim of this study was to investigate the diversity and variability of bacterial communities associated with the marine sponge Halichondria panicea with respect to tissue compartmentalization as well as seasonal and small-scale geographic variation. Diversity of microorganisms in sponges was investigated recently, but work on the variability and succession of associated bacterial communities is rare. Despite some information on Pacific and Mediterranean sponges, it is still uncertain whether bacteria and sponges are specifically associated. In this study, H. panicea specimens were sampled throughout the year at different stations around the island of Helgoland (North Sea) and investigated using molecular tools. The bacterial community associated with H. panicea was diverse, consisting of one denaturing gradient gel electrophoresis (DGGE) band occurring in most ,tissue' samples and additional variable bands. Variability was observed between different sponge fractions (i.e. the aquiferous system and the ,tissue'), sampling locations, and sampling dates. A PCR-DGGE specific for the Roseobacter group of marine Alphaproteobacteria displayed low diversity and a marked similarity between all samples. Phylogenetic analysis also pointed to specific Alphaproteobacteria of the Roseobacter group, which was predominant in most sponge ,tissue' samples. We conclude that H. panicea harbour a specific Roseobacter population with varying bacterial co-populations occurring seasonally or on a small-scale geographically, sometimes even dominating the bacterial community. [source]

Effect of thermal aging on the crystal structural characteristics of poly(tetra fluoro ethylene)

POLYMER ENGINEERING & SCIENCE, Issue 11 2007
Anjana Jain
The residual effects of cumulative thermal aging on the crystal structural characteristics of the fluoro carbon poly(tetra fluoro ethylene) (PTFE) have been studied by X-ray diffraction methods. The initial hexagonal arrangement of the PTFE chains in a 157 helical conformation is left unaffected by the exposures to temperatures (T), up to and beyond its melting point, Tm. The unit cell registers a residual anisotropic volume expansion. The anisotropy arises from the enhanced enlargement of the basal plane dimension a compared with the axial dimension c. Conformational changes contributing to the observed increase in the chain length have been examined. Enhancement of residual crystallinity of samples aged at T's < Tm suggests that the selective thermal aging could be used as an effective tool to improve the initial crystallinity of commercially available PTFE. The activation energy for 50% enhancement in initial crystallinity has been estimated as 53.9 kJ mol,1. Aging at 400°C, a temperature above Tm, is accompanied by markedly different features viz., deterioration in crystallinity and other structural characteristics. The overall behavior of thermally aged PTFE bears a marked similarity to many polyamides. POLYM. ENG. SCI., 47:1724,1729, 2007. © 2007 Society of Plastics Engineers [source]