2,692 research outputs found

    Influence of protein (human galectin-3) design on aspects of lectin activity

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    The concept of biomedical significance of the functional pairing between tissue lectins and their glycoconjugate counterreceptors has reached the mainstream of research on the flow of biological information. A major challenge now is to identify the principles of structure–activity relationships that underlie specificity of recognition and the ensuing post-binding processes. Toward this end, we focus on a distinct feature on the side of the lectin, i.e. its architecture to present the carbohydrate recognition domain (CRD). Working with a multifunctional human lectin, i.e. galectin-3, as model, its CRD is used in protein engineering to build variants with different modular assembly. Hereby, it becomes possible to compare activity features of the natural design, i.e. CRD attached to an N-terminal tail, with those of homo- and heterodimers and the tail-free protein. Thermodynamics of binding disaccharides proved full activity of all proteins at very similar affinity. The following glycan array testing revealed maintained preferential contact formation with N-acetyllactosamine oligomers and histo-blood group ABH epitopes irrespective of variant design. The study of carbohydrate-inhibitable binding of the test panel disclosed up to qualitative cell-type-dependent differences in sections of fixed murine epididymis and especially jejunum. By probing topological aspects of binding, the susceptibility to inhibition by a tetravalent glycocluster was markedly different for the wild-type vs the homodimeric variant proteins. The results teach the salient lesson that protein design matters: the type of CRD presentation can have a profound bearing on whether basically suited oligosaccharides, which for example tested positively in an array, will become binding partners in situ. When lectin-glycoconjugate aggregates (lattices) are formed, their structural organization will depend on this parameter. Further testing (ga)lectin variants will thus be instrumental (i) to define the full range of impact of altering protein assembly and (ii) to explain why certain types of design have been favored during the course of evolution, besides opening biomedical perspectives for potential applications of the novel galectin forms

    Pityriasis lichenoides et varioliformis acuta with numerous CD30(+) cells: a variant mimicking lymphomatoid papulosis and other cutaneous lymphomas. A clinicopathologic, immunohistochemical, and molecular biological study of 13 cases

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    Pityriasis lichenoides comprises a clinicopathologic spectrum of cutaneous inflammatory disorders, with the 2 most common variants being pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica. The aim of the study was to describe 13 cases of a unique PLEVA variant characterized in the conspicuous CD30 component and thus mimicking lymphomatoid papulosis (LyP), a condition currently classified in the spectrum of CD30 lymphoproliferative disorders. The cohort included 10 female and 3 male patients whose ages at diagnosis ranged from 7 to 89 years (mean 41 y; median 39 y). The clinical manifestation was that of PLEVA, with small erythematous macules quickly evolving into necrotic papules. No waxing and waning was seen on follow-up in any of the cases. Histopathologically, typical features of PLEVA were present, but an unusual finding was occurrence of a considerable number of CD30 small lymphocytes as detected immunohistochemically. Over half of the cases also displayed a large number of CD8 cells and showed coexpression of CD8 and CD30 in the intraepidermal and dermal component of the infiltrate. Of the 11 cases of PLEVA studied for T-cell receptor gene rearrangement, 6 evidenced a monoclonal T-cell population, and 5 were polyclonal. Parvovirus B19 (PVB19) DNA was identified in 4 of 10 cases investigated, and positive serology was observed for PVB19 in 2 patients, altogether suggesting that PVB19 is pathogenetically linked to PLEVA at least in a subset of cases. The presence of CD30 lymphocytes and CD8 lymphocytes would be consistent with an inflammatory antiviral response, as CD30, even atypically appearing lymphoid cells have been identified in some viral skin diseases. The main significance of the PLEVA variant is, however, its potential confusion with LyP or some cytotoxic lymphomas. Admittedly, the CD30 PLEVA variant described herein and LyP show considerable overlap if one takes into account all known variations of the 2 conditions recognized in recent years, thus suggesting that LyP and PLEVA may be much more biologically closely related entities than currently thought or can even occur on a clinicopathologic spectrum

    Primary cutaneous anaplastic large cell lymphoma with angioinvasive features and cytotoxic phenotype: a rare lymphoma variant within the spectrum of CD30+ lymphoproliferative disorders

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    BACKGROUND: Primary cutaneous anaplastic large cell lymphoma (PCALCL) presents with solitary or grouped exophytic tumors and cohesive infiltrates of large CD30+ T cells. OBJECTIVE: To report an angioinvasive variant of PCALCL. METHODS: Retrospective analysis of clinicopathological features of this variant. RESULTS: The group consisted of six patients (median age 46 years) with a solitary flat necrotic lesion preferentially located on the upper extremity. Histologically, there were angiocentric and angiodestructive infiltrates of medium-sized to large pleomorphic and anaplastic cells co-expressing CD30 and CD8. Five patients were treated with surgical excision and one patient with radiotherapy. A relapse was observed in one patient with spontaneous regression of the lesions suggesting a link to the recently described angioinvasive lymphomatoid papulosis (type E). All patients were alive without evidence of disease after a median follow-up of 31 months (range 15-96), indicating an excellent prognosis. CONCLUSIONS: The angioinvasive variant of PCALCL is rare but distinctive and prone to misinterpretation as aggressive lymphoma due to its histological features

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum