Search

A nearly 400-km-long erosion channel through the Strait of Gibraltar has been interpreted as evidence for a catastrophic refill of the Mediterranean at the end of the Messinian salinity crisis, 5.33 million years ago. This channel extends from the Gulf of Cadiz to the Algerian Basin and implies the excavation of ca. 1000 km3of Miocene sediment from the Alboran Basin and bedrock from the Strait of Gibraltar. The fate of these eroded materials remains unknown. In a first attempt to predict the distribution of those flood deposits, we develop a numerical model to simulate the transport of material eroded from the Strait of Gibraltar. It is a Lagrangian model based upon standard sediment transport equations which is able to simulate suspended and bed load sediment transport. Water circulation during the flood was obtained from a hydrodynamic model of the whole Mediterranean Sea previously developed by the authors and applied to the Zanclean flood. Five particle sizes were considered for suspended load and three for bed load transport. Areas of sediment deposition in the Mediterranean Sea were determined. In the case of suspended load, these are related to hydrodynamic conditions: areas sheltered from the jet of incoming water by local topography and areas where water currents abruptly decrease due to a sudden increase in water depth. In the case of bed load transport, sediments follow water streamlines and deposits are much more localized than in the case of suspended load. Single channel seismic records were also analysed to identify and characterize flood-related deposits in the eastern Alboran Sea.

The Eurasian‐African NW‐SE oblique plate convergence produces shortening and orthogonal extension in the Alboran Sea Basin (westernmost Mediterranean), located between the Betic and Rif Cordilleras. A NNE‐SSW broadband of deformation and seismicity affects the Alboran central part. After the 1993–1994 and 2004 seismic series, an earthquake sequence struck mainly its southern sector in 2016–2017 (main event Mw= 6.3, 25 January 2016). The near‐surface deformation is investigated using seismic profiles, multibeam bathymetry, gravity and seismicity data. Epicenters can be grouped into two main alignments. The northern WSW‐ENE alignment has reverse earthquake focal mechanisms, and in its epicentral region recent mass transport deposits occur. The southern alignment consists of a NNE‐SSW vertical sinistral deformation zone, with early epicenters of higher‐magnitude earthquakes located along a narrow band 5 to 10‐km offset westward of the Al Idrisi Fault. Here near‐surface deformation includes active NW‐SE vertical and normal faults, unmapped until now. Later, epicenters spread eastward, reaching the Al Idrisi Fault, characterized by discontinuous active NNE‐SSW vertical fractures. Seismicity and tectonic structures suggest a westward propagation of deformation and the growth at depth of incipient faults, comprising a NNE‐SSW sinistral fault zone in depth that is connected upward with NW‐SE vertical and normal faults. This recent fault zone is segmented and responsible for the seismicity in 1993–1994 in the coastal area, in 2004 onshore, and in 2016–2017 offshore. Insights for seismic hazard assessment point to the growth of recent faults that could produce potentially higher magnitude earthquakes than the already formed faults. The 2016–2017 seismic sequence is related to the wide NNE‐SSW sinistral fault zone located in the central part of the Alboran SeaEpicentral sea bottom deformations include mass transport deposits and recent faultsSeismicity and sea bottom deformations are located west of the main Al Idrisi Fault, supporting the westward widening of the fault zone

The magma‐poor rifted continental margin of Galicia has an extremely complex structure. Its formation involved several rifting episodes that occurred ultimately during the early Cretaceous near a ridge triple junction, which produced a change in the orientation of the main structures in its transition to the north Iberia margin. In addition, there is a superimposed partial tectonic inversion along its northwest and northern border which developed from the Late Cretaceous to at least Oligocene times. The present study integrates a large volume of new geophysical information (mainly marine gravity data and 2‐D seismic reflection profiles) to provide insights on the formation of this rift system and on the development of its later inversion. The combined interpretation and modeling of this data enable the presentation of a new crustal and structural domain map for the whole Galicia margin. This includes the rift domains related to the extreme thinning of the crust and the lithospheric mantle (stretched, necking, and hyperextension and mantle exhumation domains), as well as a domain of intense compressional deformation. New constraints arise on the origin, the deep structure, and the characterization of the along‐ and across‐strike variation of the continent‐ocean transition of the margin, where a progressive change from hyperextension to partial inversion is observed. The development of both rifting and later partial tectonic inversion is influenced by the existence of former first‐order tectonic features. Most of the tectonic inversion is focused on the hyperextension and mantle exhumation domain, which in some areas of the northwestern margin is completely overprinted by compressional deformation. The diverse rift‐related structural domains in the margin have distinctive gravity anomaly imprintsMapping of the crustal and structural domains shows a strong segmentation of the NW Iberia margin with high inheritance controlRift architecture and segmentation control the development of the partial tectonic inversion of the margin

The Gebra–Magia Complex is an important example of a submarine mass-movement composite located on the lower continental slope of the Antarctic Peninsula (Central Bransfield Basin). Continuous instability dynamics over time is inferred to have affected the palaeo-trough-mouth fans present in the study area.The depositional architecture and the outstanding relief of the Gebra Valley, which is the most striking morphological feature in the area, determine the asymmetrical morphology of the complex. This complex is characterized, from east to west, by an open-slope margin flanking the sidewall of the Gebra Valley, the Gebra Valley itself and a SW margin that is connected to the Magia area by a large scar approximately 7.8 km to the SW.The Gebra Valley is a Quaternary debris valley resulting from repeated large-scale mass-transport and cut-and-fill processes. In contrast, the Magia area is dominated by unchannelized sedimentary instability processes, resulting in a different sedimentary architecture and morphology. The near-surface sediments in the Gebra–Magia Complex document the continuous occurrence of recent mass movements, as also evidenced by flows transported downslope as unchannelized or channelized flows.Climate and tectonic activity are considered the primary factors controlling the development of the complex.

New putative antigenic peptides corresponding to the N- and C-terminal of the E2 envelope protein of GBVC/ HGV were synthesized using solid-phase chemistry. The antigens were obtained in linear and chimeric forms with the main aim of improving the sensitivity of the enzyme immunoassays. Furthermore, CD and FTIR have been used in conjunction to characterize their conformational changes showing that the chimeric peptide presents a more ordered secondary structure than its parent peptides.

Objective. To analyse the frequency and prognostic factors of radiographic progression in a series of Spanish patients with early rheumatoid arthritis (RA) after 1 yr of treatment with disease-modifying anti-rheumatic drugs (DMARDs).
Methods. Sixty patients (47 females, 13 males) with RA with a disease duration shorter than 2 yr [mean (s.d.) duration 9.5±6.6 months] were treated with the same therapeutic protocol using gold salts as the first DMARD and methotrexate as a second option, and were followed up for 1 yr. Radiographic progression in the hands and feet (total radiographic Larsen score and the erosion joint count) was used as the outcome variable. Clinical, laboratory, immunogenetic and radiographic data were obtained at study entry. Disease activity and response to therapy were measured at 6 and 12 months.
Results. Erosive disease was found in 21.7% of patients at baseline and in 38.3% after 1 yr. Although a substantial reduction in disease activity was observed during the 1 yr follow-up [disease activity score (DAS28) 5.8±0.8 at entry and 3.9±1.3 at 12 months, P < 0.001], the Larsen score rose from 1.9±3.3 to 5.6±9.8 after 1 yr. In 26.6% of patients, a raised erosion joint count was observed after 1 yr. Radiographic progression in the total joint radiographic damage (increase in Larsen score of ≥2) was observed in 36.6%. In the multivariate analysis, baseline pain [visual analogue scale (VAS)] and the presence of two copies of the shared epitope were associated with radiographic progression in the erosion joint count. Disease duration before study entry, VAS pain and Larsen score at baseline were significant predictors of radiographic progression in total damage (Larsen score). Baseline radiographic damage had the highest positive predictive value for progression.
Conclusions. Radiographic progression was observed in up to 36.6% of patients with early RA after 1 yr of DMARD therapy in spite of a significant reduction in disease activity. Baseline factors, such as VAS pain, disease duration until DMARD therapy, damage score at baseline and the presence of two copies of the shared epitope, were associated with radiographic progression.

Objective. To analyse the prevalence and clinical significance of anti-cyclic citrullinated peptide antibodies (anti-CCP) and antikeratin antibodies (AKA) in patients with palindromic rheumatism (PR).
Method. Sixty-three patients with PR were included: 33 were defined as pure or persistent PR at the time of serum test measurement, and 30 as associated PR, defined as patients with past history of PR who had developed persistent arthritis at the time of serum test: [21 with rheumatoid arthritis (RA)]. Sixty patients with early RA, and 80 with seronegative spondyloarthropathy were included as control groups. Anti-CCP were determined by a standardized ELISA test and AKA by indirect immunofluorescence in rat oesophagus. Clinical characteristics of these pure PR patients were compared according to the presence or absence of anti-CCP antibodies. A follow-up study was also performed.
Results. Anti-CCP were detected in 18 out of 32 (56.3%) patients with pure PR and 10 out of 30 (33.3%) with associated PR (38.1% in RA-associated PR patients). AKA were detected in 12 patients out of 33, with pure PR (36.4%), and in 9 out of 30 with associated PR (30%) (33.3% in RA-associated PR patients). The prevalence of anti-CCP and AKA in the RA control group was 55% (not significantly different from the pure PR group) and 61.7% (with respect to pure PR patients, P=0.02), respectively. In the spondyloarthropathy group, the prevalence of anti-CCP and AKA was 2.5 and 3.8%, respectively (P<0.001 compared with pure PR patients). No significant clinical differences were observed between pure PR patients with and without CCP antibodies.
Conclusions. Anti-CCP and, to a lesser extent, AKA, were found in a high proportion of patients with PR, suggesting that this syndrome is an abortive form of RA. The predictive value of these antibodies in PR, as markers of progression to an established RA, remains uncertain.

The present study was undertaken to examine the structural features of two peptide constructs designed on the basis of linear combination of B and T-cell epitopes in different orientations (BT and TB) that may be important to explain the differences in the elicited antihepatitis A virus immune response and in the interaction with biological model membranes. A CD study was carried out and the corresponding quantitative analysis of the experimental data was done using deconvolution computer programs. Moreover, fluorescence experiments were performed to analyze differences in the fluorescence emission spectra of both molecules. The main conformational difference by CD studies was obtained working in aqueous medium. Although the TB sequence adopted a preferably random coil structure, the BT peptide was best fitted with β-type structures. These results are further supported by fluorescence studies. These findings have relevance for the design of synthetic immunopeptides. © 2001 John Wiley & Sons, Inc. Biopoly 58: 117–128, 2001

A number of genes/regions have recently been reported to be linked to asthma or its related phenotypes (i.e. atopy and bronchial hyperresponsiveness), by genetic linkage and allele-sharing methods. We have performed a case–control study comparing the allelic distribution of nine microsatellite markers and two genetic variants in a group of patients attended at emergency room departments because of an acute attack of asthma with respect to an external healthy population of controls. A total of 146 asthmatic subjects and 50 population controls from Barcelona, Spain, were genotyped for nine microsatellite markers from some asthma/atopy candidate genes/regions: the β-subunit of the high-affinity IgE receptor (FcεRI-β) located on chromosome 11; the 5q31–32 candidate region; the T-cell receptor genes, TCR-α on chromosome 14 and TCR-β on chromosome 7. Two genetic variants of the β-subunit of the high-affinity IgE receptor (FcεRI-β) gene were also analyzed. None of the asthmatic or control individuals carried the Ile181Leu variant. There were no significant differences between asthmatic and control subjects neither for the polymorphic markers nor for the other variant of the β-subunit of the high-affinity IgE receptor (FcεRI-β) gene. No association could be observed in this sample of Spanish asthmatics with the genes/regions studied.

The flow cytometric enumeration of CD34+ hemopoietic precursor cells (HPC) present in samples used for transplantation of HPC has proven to be the most powerful single parameter for prediction of engraftment. At present, several different methodological approaches are used for the flow cytometric enumeration of CD34+ HPC. In the present study we have compared two of these methods as regards enumeration of CD34+ HPC and their CD34+/CD19− and CD34+/CD19+ subsets: a lyse-non-wash procedure based on the use of a recently commercialized red cell lysing solution (Quicklysis, Cytognos, Salamanca, Spain) and a lyse-and-then-wash method in which the Becton Dickinson (San Jose, CA) FACS Lysing Solution was used. For that purpose a total of 52 samples corresponding to 20 G-CSF mobilized peripheral blood (PB) samples and 21 PB-derived leucapheresis products from patients undergoing autologous PB stem cell harvest, together with 11 bone marrow (BM) samples from healthy volunteers were analyzed. Our results show that for each of the three types of samples analyzed the use of the lyse-and-then-wash method is associated with significantly lower numbers of both total CD34+ HPC (P ≤ 0.003) and its major CD34+/CD19− subset (P ≤ 0.01) while no significant changes are detected in the number of CD34+/CD19+ HPC in BM samples (P > 0.05). The use of an internal standard (reference beads) added just prior to data acquisition, showed that the differences between both methods are due to a selective loss of CD34+ HPC and its major CD34+/CD19− subset in BM (P = 0.002 and P = 0.003), PB (P < 0.0001 and P < 0.0001) and PB-derived leucapheresis products (P  < 0.0001 and P = 0.0001). Finally, addition of a centrifugation and washing step to a group of 11 leucapheresis samples lysed with Quicklysis showed that they did not significantly affect the overall number of total CD34+, CD34+/CD19− and CD34+/CD19+ HPC obtained. In line with these findings elimination of centrifugation and washing steps when FACS Lysing Solution was used to lyse mature red cells almost corrected for the selective loss of CD34+ HPC. In spite of these differences a significant degree of correlation (r > 0.83 in all cases) was found between both methods regarding the total number of CD34+, CD34+/CD19− and CD34+/CD19+ HPC present in the BM, PB and PB-derived leucapheresis samples analyzed in this study. Cytometry (Comm. Clin. Cytometry) 34:264–271, 1998. © 1998 Wiley-Liss, Inc.

Explores the sedimentary processes and depositional evolution of the turbidite environments that have developed at the transition between the feeding system (the Agadir Canyon) and the depositional area (the Agadir Basin) since the Oligocene. Methodology of the study; Evolution of the Agadir turbidite system; Details on sedimentary activity; Conclusion.

The Pleistocene sedimentary growth pattern of the northern Catalonia continental shelf is characterized by the vertical stacking of seaward downlapping regressive deposits. These deposits are characterized by a progradational development, with oblique clinoforms of low angle in the middle continental shelf, that become more inclined seaward in the outer continental shelf and shelfbreak. Eustatic sea level fluctuations controlled the development of this sedimentary pattern, whereas sediment supply conditioned the nonuniform progradation along the continental shelf and subsidence due to both sediment loading and tectonics controlled its preservation through and along the continental shelf.

Five depositional bodies occur within the Quaternary deposits of the northwestern Alboran Sea: Guadalmedina-Guadalhorce prodelta, shelf-edge wedges, progradational packages, Guadiaro channel-levee complex, and debris flow deposits. The sedimentary structure reflects two styles of margin growth characterized: 1) by an essentially sediment-starved outer, shelf and upper slope and by divergent slope seismic facies; 2) by a prograding sediment outer shelf, and parallel slope seismic facies. Eustatic oscillations, sediment supply, and tectonic tilting have controlled the type of growth pattern, and the occurrence of the depositional bodies. Debris flows were also controlled locally by diapirism.

Laboratory analysis of core samples from the western Alboran Sea slope reveal a large variability in texture and geotechnical properties. Stability analysis suggests that the sediment is stable under static gravitational loading but potentially unstable under seismic loading. Slope failures may occur if horizontal ground accelerations greater than 0.16g are seismically induced. The, Alboran Sea is an active region, on which earthquakes inducing accelerations big enough to exceed the shear strength of the soft soil may occur. Test results contrast with the apparent stability deduced from seismic profiles.

In a prospective study sixty-eight patients consecutively diagnosed as having AIDS or advanced ARC who were started on zidovudine therapy were followed up for a median period of 725 days. In the 20 patients who had a baseline p24 antigen level above 20 pg/ml, there was a statistically significant trend towards reduction of the p24 antigen levels after the first month of treatment. The median time of survival of the 68 patients was 702 days and the median symptom-free period was 510 days. Treatment with zidovudine significantly reduced the p24 antigen levels. However, the life expectancy and the symptom-free period were not statistically different in the patients with p24 antigen levels always below or with levels always above two arbitrarily chosen cut-off points of 20 pg/ml and 50 pg/ml, respectively.

The late Pleistocene-Holocene sedimentary evolution of the northern Catalonia continental shelf is interpreted as transgressive and highstand systems tracts, separated by an unconformity that seismically represents the coincidence between the ravinement surface and maximum flooding surface. During the transgressive stage, the shoreface erosion prevailed over sedimentation, leading to the development of palimpsest and relict facies. During the highstand stage, accumulation occurred only in areas with a steady supply of sediment, favouring the development of a depositional mound and the Fluviá-Muga and Ter prodeltas. Their distribution resulted from southward geostrophic current flow and the physiographic configuration of the area.

Multibeam bathymetric and ultra high-resolution seismic data reveal that the distal course of the Equatorial Atlantic Mid-Ocean Channel (EAMOC) extends further east and south than was previously known, and is controlled by the presence of morphologic highs related to the Fernando de Noronha Fracture Zone. Distal course of the EAMOC is buried by sediments, and does not have bathymetric expression on the seafloor. The channel fill consists of three seismic sequences, suggesting that the recent geological evolution of the channel is composed of successive phases of decreasing sedimentary activity that finally resulted in its complete burial. Tectonic and volcanic activity related to the Fernando de Noronha Fracture Zone and Ridge, together with the effect of strong pulses of the Antarctic bottom water current during the upper Pliocene are suggested to have contributed to the progressive burial and the final abandonment of the EAMOC.

To evaluate strategies for screening patients on hemodialysis (HD) for markers of acute and chronic hepatitis C virus (HCV) infection, we studied sixty-nine patients at a single center over a 36-month period. Serum samples were tested for alanine aminotransferase (ALT) levels, anti-HCV and HCV RNA at 3–4 month intervals. Anti-HCV was tested for by EIA1, EIA2, and RIBA2. HCV RNA was detected by polymerase chain reaction (PCR). In addition, IgM antibody to the c33 antigen of HCV was detected by an experimental EIA. Of the 43 HD patients at the start of the study, anti-HCV was detected by EIA1 in 13 (30%). All EIA1 positive patients and 14 (47%) of the 30 EIA1 negative patients tested positive by EIA2. Thus, at the start of the study 27 (63%) of 43 patients tested positive for anti-HCV by EIA2. The presence of anti-HCV among EIA2 positive patients was confirmed by RIBA2 in all patients. Based on the PCR results, the sensitivity, specificity, positive predictive value and negative predictive value for EIA1 were 48%, 100%, 53% and 100%, respectively, and for EIA2 were 100%, 100%, 100% and 100%, respectively. During follow-up, 26 EIA2 negative patients began HD in the unit. Of the 42 EIA2 negative patients, five (12%) seroconverted for anti-HCV during follow-up. All five patients with new HCV infection tested positive for HCV RNA three months prior to the detection of anti-HCV by EIA2. In addition, IgM to c33 was detected three months prior to seroconversion for anti-HCV by conventional tests in the two patients in whom testing was performed. All patients in whom HCV RNA was detected remained HCV RNA positive through the course of the study. The HCV subtype testing revealed that 25 (86%) of 29 patients had HCV type II infection and the remainder had mixed infection with both type I and II. The results of this study demonstrate that EIA2 is a reliable predictor of HCV infection among HD patients, and that RIBA2 or PCR testing is not necessary in routine clinical practice. Further, clearance of viremia and recovery from HCV infection is unusual, and hence regular testing for HCV should be limited to patients who are EIA2 negative. Serum ALT levels and conventional anti-HCV tests are poor predictors of early HCV infection. The anti-c33 IgM test may have a role in the identification of individuals with early HCV infection.

Since the Miocene, the thinned continental crust below the Alboran Sea and its overlying sedimentary cover have been undergoing deformation caused by both convergence of Eurasia and Africa and by deep processes related to the Tethyan slab retreat. Part of this deformation is recorded at the Xauen and Tofiño banks in the southern Alboran Sea. Using swath bathymetry and multichannel seismic reflection data, we identified different stages and styles of deformation. The South Alboran Basin is made up of Early Miocene to Pliocene sedimentary layers that correlate with the West Alboran Basin depocenter and are dominated by E‐W trending folds and thrusts. The Xauen and Tofiño Banks first recorded the phase of extension and strike‐slip movement during the slab retreat, followed by the phase of compressional inversion since the Tortonian and are now structured by tight folds, thrusts, and mud bodies. This study proposes that the Banks were located on the southern‐inherited Subduction Tear Edge Propagator (STEP) fault related to the westward migration of the Alboran domain during the Miocene. The STEP fault zone, acting as a boundary between the African block and the Alboran block, was located along the onshore Jebha‐Nekor fault and the offshore Alboran Ridge and the Yusuf fault zone. Thick‐skinned and thin‐skinned shortening occurred when slab retreat stopped, and inversion began. The present‐day style of the deformation seems to be linked to a decollement level made of undercompacted shale on top of the Ghomaride complex. The reactivation of the Subduction Tear Edge Propagator fault zone on the southern edge of the Alboran Domain forms the South Alboran RidgeThe style of the present‐day structure of the South Alboran region implies an interaction between thick‐skinned and thin‐skinned tectonicsUndercompacted shales and inherited crustal structures are involved in the structural evolution of the South Alboran Basin

Three pedigrees informative for the segregation of genetic variants of the binding protein for the fourth component of complement (C4BP) and C3b/C4b receptor (C3bR) have been identified. There were 10 informative meioses with no recombinants, indicating a close linkage between the loci encoding C4BP and C3bR, C4BP and C3bR [maximum lod (logarithm of odds of linkage) score: 2.4 at recombinant fraction = 0.0]. In addition, in the four unrelated individuals who were doubly heterozygous (C4BP*1, C4BP*2, C3bR*A, C3bR*B), the infrequent allele C4BP*2 segregated together with the uncommon allele C3bR*B, supporting the hypothesis of linkage between C4BP and C3bR and suggesting that linkage disequilibrium exists between these particular alleles. We conclude that the loci encoding C3bR and C4BP, two functionally related molecules, are linked.

Laboratorie d’Immuno-Hématologie Unité INSERM U93 Center Hoyem Hopital Saint-Louis, 75475 Paris Cedex 10, France, and Unidad de Immunologia Hospital Clinico Barcelona 11, Spain