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1.
Scand J Rheumatol ; 51(6): 470-480, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-34514929

RESUMEN

OBJECTIVE: In patients with rheumatoid arthritis (RA) in sustained remission, tapering of biological disease-modifying anti-rheumatic drugs can be considered. Tapering has already been investigated, but its feasibility remains to be determined. Therefore, we explored the feasibility of tapering etanercept in RA in a setting close to practice. METHOD: Patients with RA in 28-joint Disease Activity Score (DAS28) remission (≥ 6 months) and treated with etanercept 50 mg weekly (≥ 1 year) were included in the pragmatic 1 year open-label multicentre randomized controlled TapERA (Tapering Etanercept in Rheumatoid Arthritis) trial. Patients were assigned to continue etanercept weekly or to taper to every other week (EOW). Patients who lost remission [DAS28-C-reactive protein (CRP) ≥ 2.6] were re-escalated to etanercept weekly. The primary outcome was the proportion of patients maintaining DAS28-CRP remission for 6 months. RESULTS: Sixty-six patients were randomized to etanercept weekly (n = 34) or EOW (n = 32). After 6 months, 26/34 patients (76%) in the weekly and 19/32 (59%) in the EOW group maintained disease control (p = 0.136). In the EOW group, 20/32 patients (63%) remained on their tapered treatment during the trial. Two patients reintroduced weekly etanercept themselves. Ten patients were re-escalated to etanercept weekly by the rheumatologist, after a median (interquartile range) interval of 3.0 (2.0-6.0) months. Among these patients, 7/10 regained remission after re-escalation, four of them at the next study visit. CONCLUSIONS: Although non-inferiority could not be demonstrated, tapering of etanercept to EOW appeared feasible in patients in sustained remission.


Asunto(s)
Antirreumáticos , Artritis Reumatoide , Humanos , Etanercept/uso terapéutico , Resultado del Tratamiento , Artritis Reumatoide/tratamiento farmacológico , Antirreumáticos/uso terapéutico , Proteína C-Reactiva , Inducción de Remisión
2.
Geophys Res Lett ; 49(20): e2022GL099330, 2022 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-36589269

RESUMEN

Sub-grid-scale processes occurring at or near the surface of an ice sheet have a potentially large impact on local and integrated net accumulation of snow via redistribution and sublimation. Given observational complexity, they are either ignored or parameterized over large-length scales. Here, we train random forest (RF) models to predict variability in net accumulation over the Antarctic Ice Sheet using atmospheric variables and topographic characteristics as predictors at 1 km resolution. Observations of net snow accumulation from both in situ and airborne radar data provide the input observable targets needed to train the RF models. We find that local net accumulation deviates by as much as 172% of the atmospheric model mean. The correlation in space between the predicted net accumulation variability and satellite-derived surface-height change indicates that surface processes operate differently through time, driven largely by the seasonal anomalies in snow accumulation.

3.
Geophys Res Lett ; 47(15): e2020GL087970, 2020 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-32999516

RESUMEN

Between 1992 and 2017, the Antarctic Ice Sheet (AIS) lost ice equivalent to 7.6 ± 3.9 mm of sea level rise. AIS mass loss is mitigated by ice shelves that provide a buttress by regulating ice flow from tributary glaciers. However, ice-shelf stability is threatened by meltwater ponding, which may initiate, or reactivate preexisting, fractures, currently poorly understood processes. Here, through ground penetrating radar (GPR) analysis over a buried lake in the grounding zone of an East Antarctic ice shelf, we present the first field observations of a lake drainage event in Antarctica via vertical fractures. Concurrent with the lake drainage event, we observe a decrease in surface elevation and an increase in Sentinel-1 backscatter. Finally, we suggest that fractures that are initiated or reactivated by lake drainage events in a grounding zone will propagate with ice flow onto the ice shelf itself, where they may have implications for its stability.

4.
Nature ; 502(7469): 89-92, 2013 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-24037377

RESUMEN

Iceberg calving has been assumed to be the dominant cause of mass loss for the Antarctic ice sheet, with previous estimates of the calving flux exceeding 2,000 gigatonnes per year. More recently, the importance of melting by the ocean has been demonstrated close to the grounding line and near the calving front. So far, however, no study has reliably quantified the calving flux and the basal mass balance (the balance between accretion and ablation at the ice-shelf base) for the whole of Antarctica. The distribution of fresh water in the Southern Ocean and its partitioning between the liquid and solid phases is therefore poorly constrained. Here we estimate the mass balance components for all ice shelves in Antarctica, using satellite measurements of calving flux and grounding-line flux, modelled ice-shelf snow accumulation rates and a regional scaling that accounts for unsurveyed areas. We obtain a total calving flux of 1,321 ± 144 gigatonnes per year and a total basal mass balance of -1,454 ± 174 gigatonnes per year. This means that about half of the ice-sheet surface mass gain is lost through oceanic erosion before reaching the ice front, and the calving flux is about 34 per cent less than previous estimates derived from iceberg tracking. In addition, the fraction of mass loss due to basal processes varies from about 10 to 90 per cent between ice shelves. We find a significant positive correlation between basal mass loss and surface elevation change for ice shelves experiencing surface lowering and enhanced discharge. We suggest that basal mass loss is a valuable metric for predicting future ice-shelf vulnerability to oceanic forcing.


Asunto(s)
Congelación , Cubierta de Hielo , Modelos Teóricos , Regiones Antárticas , Comunicaciones por Satélite
5.
Ann Rheum Dis ; 74(1): 27-34, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25359382

RESUMEN

OBJECTIVES: To compare the efficacy and safety of intensive combination strategies with glucocorticoids (GCs) in the first 16 weeks (W) of early rheumatoid arthritis (eRA) treatment, focusing on high-risk patients, in the Care in early RA trial. METHODS: 400 disease-modifying antirheumatic drugs (DMARD)-naive patients with eRA were recruited and stratified into high risk or low risk according to classical prognostic markers. High-risk patients (n=290) were randomised to 1/3 treatment strategies: combination therapy for early rheumatoid arthritis (COBRA) Classic (methotrexate (MTX)+ sulfasalazine+60 mg prednisone tapered to 7.5 mg daily from W7), COBRA Slim (MTX+30 mg prednisone tapered to 5 mg from W6) and COBRA Avant-Garde (MTX+leflunomide+30 mg prednisone tapered to 5 mg from W6). Treatment modifications to target low-disease activity were mandatory from W8, if desirable and feasible according to the rheumatologist. The primary outcome was remission (28 joint disease activity score calculated with C-reactive protein <2.6) at W16 (intention-to-treat analysis). Secondary endpoints were good European League Against Rheumatism response, clinically meaningful health assessment questionnaire (HAQ) response and HAQ equal to zero. Adverse events (AEs) were registered. RESULTS: Data from 98 Classic, 98 Slim and 94 Avant-Garde patients were analysed. At W16, remission was reached in 70.4% Classic, 73.6% Slim and 68.1% Avant-Garde patients (p=0.713). Likewise, no significant differences were shown in other secondary endpoints. However, therapy-related AEs were reported in 61.2% of Classic, in 46.9% of Slim and in 69.1% of Avant-Garde patients (p=0.006). CONCLUSIONS: For high-risk eRA, MTX associated with a moderate step-down dose of GCs was as effective in inducing remission at W16 as DMARD combination therapies with moderate or high step-down GC doses and it showed a more favourable short-term safety profile. EUDRACT NUMBER: 2008-007225-39.


Asunto(s)
Antirreumáticos/uso terapéutico , Artritis Reumatoide/tratamiento farmacológico , Glucocorticoides/uso terapéutico , Isoxazoles/uso terapéutico , Metotrexato/uso terapéutico , Prednisona/uso terapéutico , Sulfasalazina/uso terapéutico , Adulto , Anciano , Artritis Reumatoide/diagnóstico , Quimioterapia Combinada/métodos , Intervención Médica Temprana , Femenino , Humanos , Quimioterapia de Inducción/métodos , Leflunamida , Masculino , Persona de Mediana Edad , Medición de Riesgo , Índice de Severidad de la Enfermedad , Resultado del Tratamiento
6.
Ann Rheum Dis ; 73(1): 108-13, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23740231

RESUMEN

OBJECTIVE: To investigate whether biologic-free remission can be achieved in patients with early, active axial spondyloarthritis (SpA) who were in partial remission after 28 weeks of infliximab (IFX)+naproxen (NPX) or placebo (PBO)+NPX treatment and whether treatment with NPX was superior to no treatment to maintain disease control. METHOD: Infliximab as First-Line Therapy in Patients with Early Active Axial Spondyloarthritis Trial (INFAST) Part 1 was a double-blind, randomised, controlled trial in biologic-naïve patients with early, active, moderate-to-severe axial SpA treated with either IFX 5 mg/kg+NPX 1000 mg/d or PBO+NPX 1000 mg/d for 28 weeks. Patients achieving Assessment of SpondyloArthritis international Society (ASAS) partial remission at week 28 continued to Part 2 and were randomised (1:1) to NPX or no treatment until week 52. Treatment group differences in ASAS partial remission and other efficacy variables were assessed through week 52 with Fisher exact tests. RESULTS: At week 52, similar percentages of patients in the NPX group (47.5%, 19/40) and the no-treatment group (40.0%, 16/40) maintained partial remission, p=0.65. Median duration of partial remission was 23 weeks in the NPX group and 12.6 weeks in the no-treatment group (p=0.38). Mean Bath Ankylosing Spondylitis Disease Activity Index scores were low at week 28, the start of follow-up treatment (NPX, 0.7; no treatment, 0.6), and remained low at week 52 (NPX, 1.2; no treatment, 1.7). CONCLUSIONS: In axial SpA patients who reached partial remission after treatment with either IFX+NPX or NPX alone, disease activity remained low, and about half of patients remained in remission during 6 months in which NPX was continued or all treatments were stopped.


Asunto(s)
Antiinflamatorios no Esteroideos/administración & dosificación , Naproxeno/administración & dosificación , Espondiloartritis/tratamiento farmacológico , Espondilitis Anquilosante/tratamiento farmacológico , Adolescente , Adulto , Antiinflamatorios no Esteroideos/efectos adversos , Método Doble Ciego , Diagnóstico Precoz , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Naproxeno/efectos adversos , Placebos , Inducción de Remisión , Espondiloartritis/diagnóstico , Espondilitis Anquilosante/diagnóstico , Resultado del Tratamiento , Adulto Joven
7.
Ann Rheum Dis ; 73(1): 101-7, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23696633

RESUMEN

OBJECTIVES: To assess whether combination therapy with infliximab (IFX) plus nonsteroidal anti-inflammatory drugs (NSAIDs) is superior to NSAID monotherapy for reaching Assessment of SpondyloArthritis international Society (ASAS) partial remission in patients with early, active axial spondyloarthritis (SpA) who were naïve to NSAIDs or received a submaximal dose of NSAIDs. METHODS: Patients were randomised (2 : 1 ratio) to receive naproxen (NPX) 1000 mg daily plus either IFX 5 mg/kg or placebo (PBO) at weeks 0, 2, 6, 12, 18 and 24. The primary efficacy measure was the percentage of patients who met ASAS partial remission criteria at week 28. Several other measures of disease activity, clinical symptoms and patient-rated outcomes were evaluated. Treatment group differences were analysed with Fisher exact tests or analysis of covariance. RESULTS: A greater percentage of patients achieved ASAS partial remission in the IFX+NPX group (61.9%; 65/105) than in the PBO+NPX group (35.3%; 18/51) at week 28 (p=0.002) and at all other visits (p<0.05, all comparisons). Results of most other disease activity and patient-reported endpoints (including Ankylosing Spondylitis Disease Activity Score, Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, multiple quality of life measures and pain measures) showed greater improvement in the IFX+NPX group than the PBO+NPX group, with several measures demonstrating early and consistent improvement over 28 weeks of treatment. CONCLUSIONS: Patients with early, active axial SpA who received IFX+NPX combination treatment were twice as likely to achieve clinical remission as patients who received NPX alone. NPX alone led to clinical remission in a third of patients.


Asunto(s)
Antiinflamatorios no Esteroideos/administración & dosificación , Anticuerpos Monoclonales/administración & dosificación , Antirreumáticos/administración & dosificación , Naproxeno/administración & dosificación , Espondiloartritis/tratamiento farmacológico , Espondilitis Anquilosante/tratamiento farmacológico , Adolescente , Adulto , Antiinflamatorios no Esteroideos/efectos adversos , Anticuerpos Monoclonales/efectos adversos , Antirreumáticos/efectos adversos , Método Doble Ciego , Quimioterapia Combinada , Diagnóstico Precoz , Femenino , Humanos , Infliximab , Masculino , Persona de Mediana Edad , Naproxeno/efectos adversos , Placebos , Espondiloartritis/diagnóstico , Espondilitis Anquilosante/diagnóstico , Resultado del Tratamiento , Adulto Joven
8.
Acta Clin Belg ; 79(1): 26-33, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38108332

RESUMEN

Despite the low prevalence of each rare disease, the total burden is high. Patients with rare diseases encounter numerous barriers, including delayed diagnosis and limited access to high-quality treatments. In order to tackle these challenges, the European Commission launched the European Reference Networks (ERNs), cross-border networks of healthcare providers and patients representatives. In parallel, the aims and structure of these ERNs were translated at the federal and regional levels, resulting in the creation of the Flemish Network of Rare Diseases. In line with the mission of the ERNs and to ensure equal access to care, we describe as first patient pathways for systemic sclerosis (SSc), as a pilot model for other rare connective and musculoskeletal diseases. Consensus was reached on following key messages: 1. Patients with SSc should have multidisciplinary clinical and investigational evaluations in a tertiary reference expert centre at baseline, and subsequently every three to 5 years. Intermediately, a yearly clinical evaluation should be provided in the reference centre, whilst SSc technical evaluations are permissionably executed in a centre that follows SSc-specific clinical practice guidelines. In between, monitoring can take place in secondary care units, under the condition that qualitative examinations and care including interactive multidisciplinary consultations can be provided. 2. Patients with early diffuse cutaneous SSc, (progressive) interstitial lung disease and/or pulmonary arterial hypertension should undergo regular evaluations in specialised tertiary care reference institutions. 3. Monitoring of patients with progressive interstitial lung disease and/or pulmonary (arterial) hypertension will be done in agreement with experts of ERN LUNG.


Asunto(s)
Enfermedades del Tejido Conjuntivo , Enfermedades Pulmonares Intersticiales , Esclerodermia Difusa , Esclerodermia Sistémica , Humanos , Enfermedades Raras/complicaciones , Enfermedades Raras/epidemiología , Enfermedades Raras/terapia , Esclerodermia Sistémica/diagnóstico , Esclerodermia Sistémica/terapia , Enfermedades del Tejido Conjuntivo/diagnóstico , Enfermedades del Tejido Conjuntivo/complicaciones , Enfermedades Pulmonares Intersticiales/diagnóstico , Enfermedades Pulmonares Intersticiales/terapia , Enfermedades Pulmonares Intersticiales/complicaciones
9.
Nat Commun ; 13(1): 4205, 2022 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-35864084

RESUMEN

Clouds regulate the Greenland Ice Sheet's surface energy balance through the competing effects of shortwave radiation shading and longwave radiation trapping. However, the relative importance of these effects within Greenland's narrow ablation zone, where nearly all meltwater runoff is produced, remains poorly quantified. Here we use machine learning to merge MODIS, CloudSat, and CALIPSO satellite observations to produce a high-resolution cloud radiative effect product. For the period 2003-2020, we find that a 1% change in cloudiness has little effect (±0.16 W m-2) on summer net radiative fluxes in the ablation zone because the warming and cooling effects of clouds compensate. However, by 2100 (SSP5-8.5 scenario), radiative fluxes in the ablation zone will become more than twice as sensitive (±0.39 W m-2) to changes in cloudiness due to reduced surface albedo. Accurate representation of clouds will therefore become increasingly important for forecasting the Greenland Ice Sheet's contribution to global sea-level rise.

10.
J Exp Med ; 176(1): 59-65, 1992 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-1613466

RESUMEN

Cytokine-stimulated human osteosarcoma cells (MG-63) secrete several related chemotactic factors, including the neutrophil-activating protein interleukin 8 (IL-8) and the monocyte chemotactic protein (MCP)-1. We describe the isolation and characterization of two novel monocyte chemotactic factors from this tumor cell line. Although these proteins copurified with MCP-1 and IL-8 on heparin-Sepharose, they could be separated by cation-exchange fast protein liquid chromatography and reverse-phase high-performance liquid chromatography. The corresponding 7.5- and 11-kD proteins were NH2-terminally blocked but were identified by sequencing peptide fragments. They showed a primary structure mostly related to that of MCP-1 and were therefore designated MCP-2 and MCP-3, respectively. These molecules can be classified in a subfamily of proinflammatory proteins characterized by the conservation of cysteine residues. MCP-2 and MCP-3 are also functionally related to MCP-1 because they specifically attract monocytes, but not neutrophils, in vitro. The chemotactic potency (specific activity) was comparable for all three MCPs. Intradermal injection of these proteins in rabbits resulted in selective monocyte recruitment in vivo. Since tumor cells are good producers of leukocyte chemotactic factors, it could be questioned whether these molecules can indirectly control tumor growth by attracting leukocytes or whether they rather promote invasion by the secretion of proteases from the attracted cells.


Asunto(s)
Factores Quimiotácticos/fisiología , Secuencia de Aminoácidos , Animales , Quimiocina CCL2 , Factores Quimiotácticos/química , Factores Quimiotácticos/aislamiento & purificación , Quimiotaxis , Humanos , Datos de Secuencia Molecular , Monocitos/inmunología , Conejos
11.
Nat Commun ; 8: 14730, 2017 03 31.
Artículo en Inglés | MEDLINE | ID: mdl-28361871

RESUMEN

Melting of the Greenland ice sheet (GrIS) and its peripheral glaciers and ice caps (GICs) contributes about 43% to contemporary sea level rise. While patterns of GrIS mass loss are well studied, the spatial and temporal evolution of GICs mass loss and the acting processes have remained unclear. Here we use a novel, 1 km surface mass balance product, evaluated against in situ and remote sensing data, to identify 1997 (±5 years) as a tipping point for GICs mass balance. That year marks the onset of a rapid deterioration in the capacity of the GICs firn to refreeze meltwater. Consequently, GICs runoff increases 65% faster than meltwater production, tripling the post-1997 mass loss to 36±16 Gt-1, or ∼14% of the Greenland total. In sharp contrast, the extensive inland firn of the GrIS retains most of its refreezing capacity for now, buffering 22% of the increased meltwater production. This underlines the very different response of the GICs and GrIS to atmospheric warming.

12.
Nat Commun ; 7: 10266, 2016 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-26756470

RESUMEN

The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data and snow model simulations. This impact results from a cloud radiative effect of 29.5 (±5.2) W m(-2). Contrary to conventional wisdom, however, the Greenland ice sheet responds to this energy through a new pathway by which clouds reduce meltwater refreezing as opposed to increasing surface melt directly, thereby accelerating bare-ice exposure and enhancing meltwater runoff. The high sensitivity of the Greenland ice sheet to both ice-only and liquid-bearing clouds highlights the need for accurate cloud representations in climate models, to better predict future contributions of the Greenland ice sheet to global sea level rise.

13.
J Mass Spectrom ; 40(5): 615-27, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15712231

RESUMEN

A series of cationic, zwitterionic and anionic fluorinated carbocyanine dyes, spin-coated on Si substrates, were measured with time-of-flight static secondary ion mass spectrometry (TOF-S-SIMS) under Ga(+) primary ion bombardment. Detailed fragmentation patterns were developed for all dyes measured. In the positive mode, the resulting spectra showed very intense signals for the precursor ions of the cationic dyes, whereas the protonated signals of the anionic dyes were hardly detected. Differences of three orders of magnitude were repeatedly observed for the secondary ion signal intensities of cationic and anionic dyes, respectively. All measured dyes yielded mass spectra containing several characteristic fragment ions. Although the secondary ion yields were still higher for the cationic than the anionic dye fragments, the difference was reduced to a factor of < or =10. This result and the fact that M(+), [M + H](+) or [M + 2H](+) are even-electron species make it very likely that the recorded fragments were not formed directly out of the (protonated) parent ions M(+), [M + H](+) or [M + 2H](+). In the negative mode, none of the recorded spectra contained molecular information. Only signals originating from some characteristic elements of the molecules (F, Cl), the anionic counter ion signal and some low-mass organic ions were detected. A comparative study was made between TOF-S-SIMS, using Ga(+) primary ions, and other mass spectrometric techniques, namely fast atom bombardment (FAB), electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). The measurements showed that MALDI, ESI and FAB all give rise to spectra containing molecular ion signals. ESI and FAB produced M(+) and [M + H](+) signals, originating from the cationic and zwitterionic dyes, in the positive mode and M(-) and [M - H](-) signals of the anionic and zwitterionic dyes in the negative mode. With MALDI, molecular ion signals were measured in both modes for all the dyes. Structural fragment ions were detected for FAB, ESI and MALDI in both the positive and negative modes. Compared with the other techniques, TOF-S-SIMS induced a higher degree of fragmentation.

14.
J Leukoc Biol ; 63(3): 364-72, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9500525

RESUMEN

Monocyte chemotactic protein (MCP)-1 and MCP-2, two closely related CC chemokines, are important mediators of monocyte and lymphocyte migration. These chemokines are secreted by various normal cell types, including fibroblasts, epithelial cells, and leukocytes, as well as by tumor cells. After stimulation with different cytokines and cytokine inducers the MCP-2 production levels are always lower than those of MCP-1. In human diploid fibroblasts cytokines differentially regulate chemokine induction, interleukin (IL)-1beta and interferon (IFN)-gamma being potent stimuli of MCP-1 and MCP-2, respectively. Co-stimulation of fibroblasts by 10 U/mL IL-1beta and 20 ng/mL IFN-gamma resulted in a synergistic induction of MCP-2, whereas the combined effect on MCP-1 and IL-6 production was rather additive. These findings were confirmed at the mRNA level by Northern blot analysis. In contrast, in human MG-63 fibroblastoid cells and HEp-2 epithelial cells, selected for their poor responsiveness to IL-1beta and IFN-gamma, MCP-2 as well as MCP-1 and IL-6 were synergistically induced, yielding protein levels that were increased 3- to 30-fold above the additive levels. When IFN-beta was used as a co-stimulant of IL-1beta, a similar synergistic induction of MCP-1 and MCP-2 was measured both at the protein and the mRNA level. It can be concluded that, when synergy occurred, the MCP-1 and MCP-2 expression levels reached a comparable maximum, indicative for an equal contribution of these chemokines in normal and pathological conditions.


Asunto(s)
Quimiocina CCL2/biosíntesis , Interferón beta/farmacología , Interferón gamma/farmacología , Interleucina-1/farmacología , Proteínas Quimioatrayentes de Monocitos/biosíntesis , División Celular/efectos de los fármacos , Línea Celular , Quimiocina CCL8 , Sinergismo Farmacológico , Células Epiteliales/inmunología , Fibroblastos/inmunología , Humanos , Interleucina-6/farmacología , ARN Mensajero/biosíntesis , Proteínas Recombinantes/farmacología , Transcripción Genética/efectos de los fármacos , Transcripción Genética/inmunología , Células Tumorales Cultivadas
15.
FEBS Lett ; 432(1-2): 73-6, 1998 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-9710254

RESUMEN

The chemokine stromal-cell-derived factor-1alpha (SDF-1alpha) chemoattracts lymphocytes and CD34+ haematopoietic progenitors and is the ligand for CXCR4 (CXC chemokine receptor 4), the main co-receptor for T-tropic HIV-1 strains. SDF-1alpha was NH2-terminally cleaved to SDF-1alpha(3-68) by dipeptidyl-peptidase IV (CD26/DPP IV), which is present in blood in soluble and membrane-bound form. SDF-1alpha(3-68) lost both lymphocyte chemotactic and CXCR4-signaling properties. However, SDF-1alpha(3-68) still desensitized the SDF-1alpha(1-68)-induced Ca2+ response. In contrast to CD26/DPP IV-processed RANTES(3-68), SDF-1alpha(3-68) had diminished potency to inhibit HIV-1 infection. Thus, CD26/DPP IV impairs the inflammatory and haematopoietic potency of chemokines but plays a dual role in AIDS.


Asunto(s)
Fármacos Anti-VIH/farmacología , Quimiocinas CXC/farmacología , Dipeptidil Peptidasa 4/metabolismo , Fragmentos de Péptidos/farmacología , Procesamiento Proteico-Postraduccional , Fármacos Anti-VIH/metabolismo , Quimiocina CXCL12 , Quimiocinas , Quimiocinas CXC/metabolismo , Quimiotaxis de Leucocito , Relación Dosis-Respuesta a Droga , VIH-1/efectos de los fármacos , Humanos , Linfocitos , Receptores CXCR4/metabolismo , Transducción de Señal
16.
J Immunol Methods ; 174(1-2): 237-47, 1994 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-8083528

RESUMEN

Phagocyte recruitment is an important immunological phenomenon in inflammation and cancer. A large family of selective chemotactic cytokines, designated chemokines, has recently emerged. Interleukin-8 (IL-8) is the prototype of such neutrophil activating factors, whereas MCP-1 is a well studied monocyte chemotactic protein. In vitro chemotactic assays were used to isolate and identify natural chemokines from mononuclear phagocytes and tumor cells. Additional new chemotactic proteins (MCP-2, MCP-3) attracting monocytes were also discovered by these methods. All chemokines are structurally related and show affinity for heparin. MCP-1, -2 and -3 have a comparable specific activity in monocyte chemotaxis assays. Specific and sensitive radioimmunoassays for MCP-1 and IL-8 were developed to study the regulation of their secretion by leukocytes. Monocytes or monocyte tumor cells produce MCP-1 and/or IL-8 in response to cytokines, virus, double stranded RNA, bacterial endotoxin, mitogen or phorbol ester. Granulocytes were found to secrete only minor amounts of MCP-1 and IL-8.


Asunto(s)
Factores Quimiotácticos/aislamiento & purificación , Factores Quimiotácticos/fisiología , Granulocitos/fisiología , Monocitos/fisiología , Neutrófilos/fisiología , Secuencia de Aminoácidos , Quimiotaxis de Leucocito , Humanos , Interleucina-8/metabolismo , Datos de Secuencia Molecular , Proteínas Quimioatrayentes de Monocitos , Familia de Multigenes , Alineación de Secuencia , Homología de Secuencia de Aminoácido
17.
Clin Exp Rheumatol ; 9(4): 407-9, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1934692

RESUMEN

This report describes a 68-year-old woman with SLE and positive antiphospholipid antibodies who developed an acute Addisonian crisis due to bilateral adrenal hemorrhage. We suggest that adrenal bleeding can be part of the thrombo-embolic complications seen in the secondary antiphospholipid syndrome.


Asunto(s)
Enfermedad de Addison/etiología , Enfermedades de las Glándulas Suprarrenales/complicaciones , Síndrome Antifosfolípido/complicaciones , Hemorragia/complicaciones , Lupus Eritematoso Sistémico/etiología , Anciano , Síndrome Antifosfolípido/inmunología , Femenino , Humanos , Imagen por Resonancia Magnética
20.
J Rheumatol ; 21(5): 961-3, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-8064743

RESUMEN

We describe a 47-year-old woman with an unusual combination of clinical signs and symptoms: short stature, oldish appearance with distinct craniofacial stigmata, talipes equinovari with adduction position of the forefeet, subluxations of the interphalangeal joints of hands and toes, carpal synostosis and progressive panhypogammaglobulinemia. Partial expression of the syndrome could be documented in different members of this family over 5 generations. Among the different possible differential diagnoses, the possibility of a variant example of Larsen syndrome is discussed.


Asunto(s)
Anomalías Múltiples , Agammaglobulinemia/complicaciones , Pie Equinovaro/patología , Enanismo/patología , Progeria/patología , Pie Equinovaro/genética , Enanismo/diagnóstico por imagen , Enanismo/genética , Femenino , Humanos , Persona de Mediana Edad , Linaje , Progeria/genética , Radiografía , Síndrome
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