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2.
Proc Natl Acad Sci U S A ; 116(24): 11567-11569, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31164417
3.
Clin Rheumatol ; 38(10): 2737-2746, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31161486

RESUMO

OBJECTIVES: To identify baseline predictors of remission and low disease activity (LDA) in early rheumatoid arthritis (RA) from the GLADAR (Grupo Latino Americano De estudio de la Artritis Reumatoide) cohort. METHODS: Patients with 1- and 2-year follow-up visits were included. Remission and LDA were defined by DAS28-ESR (< 2.6 and ≤ 3.2, respectively). Baseline predictors examined were gender, ethnicity, age at diagnosis, socioeconomic status, symptoms' duration, DMARDs, RF, thrombocytosis, anemia, morning stiffness, DAS28-ESR (and its components), HAQ-DI, DMARDs and corticosteroid use, and Sharp-VDH score. Multivariable binary logistic regression models (excluding DAS28-ESR components to avoid over adjustment) were derived using a backward selection method (α-level set at 0.05). RESULTS: Four hundred ninety-eight patients were included. Remission and LDA/remission were met by 19.3% and 32.5% at the 1-year visit, respectively. For the 280 patients followed for 2 years, these outcomes were met by 24.3% and 38.9%, respectively. Predictors of remission at 1 year were a lower DAS28-ESR (OR 1.17; CI 1.07-1.27; p = 0.001) and HAQ-DI (OR 1.48; CI 1.04-2.10; p = 0.028). At 2 years, only DAS28-ESR (OR 1.40; CI 1.17-1.6; p < 0.001) was a predictor. Predictors of LDA/remission at 1 year were DAS28-ESR (OR 1.42; CI 1.26-1.61; p < 0.001), non-use of corticosteroid (OR 1.74; CI 1.11-2.44; p = 0.008), and male gender (OR 1.77; CI 1.2-2.63; p = 0.036). A lower baseline DAS28-ESR (OR 1.45; CI 1.23-1.70; p < 0.001) was the only predictor of LDA/remission at 2 years. CONCLUSIONS: A lower disease activity consistently predicted remission and LDA/remission at 1 and 2 years of follow-up in early RA patients from the GLADAR cohort. Key Points • In patients with early RA, a lower disease activity at first visit is a strong clinical predictor of achieving remission and LDA subsequently. • Other clinical predictors of remission and LDA to keep in mind in these patients are male gender, non-use of corticosteroids and low disability at baseline. • Not using corticosteroids at first visit is associated with a lower disease activity and predicts LDA/remission at 1 year in these patients.

4.
Proc Natl Acad Sci U S A ; 116(20): 9820-9824, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31036653

RESUMO

Middle to Late Pleistocene human evolution in East Asia has remained controversial regarding the extent of morphological continuity through archaic humans and to modern humans. Newly found ∼300,000-y-old human remains from Hualongdong (HLD), China, including a largely complete skull (HLD 6), share East Asian Middle Pleistocene (MPl) human traits of a low vault with a frontal keel (but no parietal sagittal keel or angular torus), a low and wide nasal aperture, a pronounced supraorbital torus (especially medially), a nonlevel nasal floor, and small or absent third molars. It lacks a malar incisure but has a large superior medial pterygoid tubercle. HLD 6 also exhibits a relatively flat superior face, a more vertical mandibular symphysis, a pronounced mental trigone, and simple occlusal morphology, foreshadowing modern human morphology. The HLD human fossils thus variably resemble other later MPl East Asian remains, but add to the overall variation in the sample. Their configurations, with those of other Middle and early Late Pleistocene East Asian remains, support archaic human regional continuity and provide a background to the subsequent archaic-to-modern human transition in the region.

5.
Rheumatology (Oxford) ; 58(9): 1655-1661, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30938432

RESUMO

OBJECTIVES: The objective of this study was to compare the results obtained from different assays for the detection of anti-Mi-2 antibodies, which are important markers in the diagnosis of DM. METHODS: The study included 82 patients (68 females/14 males), most of whom had DM (n = 57), followed by PM (n = 16) and juvenile DM (n = 9). All samples were tested using a novel particle-based multi-analyte technology (PMAT) (Inova Diagnostics, research use only) in parallel with a line immunoassay (LIA: Euroimmun). To assess clinical specificity for the PMAT assay, a total of 775 disease and healthy controls were tested. RESULTS: 29 samples were positive by at least one test for anti-Mi-2 antibodies. Of those, 24 were Mi-2ß LIA+, five were Mi-2α LIA+ and 23 Mi-2 PMAT+. The comparison shows varying agreement between the different methods (kappa 0.27-0.77). When LIA results were used as reference for receiver operating characteristics analysis, high area under the curve values were found for both PMAT vs LIA Mi-2α and LIA Mi-2ß. When analysing the results in the context of the myositis phenotype, PMAT associated closest with the DM phenotype. In the control group, 3/775 controls (all low levels) were anti-Mi-2+ resulting in a sensitivity and specificity of 28.1% and 99.6%, respectively. CONCLUSION: Overall, good agreement was found between LIA and PMAT for anti-Mi-2 antibodies, which is important for the standardization of autoantibodies. Anti-Mi-2ß antibodies measured by PMAT tend be more highly associated with the clinical phenotype of DM.

6.
Clin Chem Lab Med ; 57(11): 1754-1763, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31005948

RESUMO

Background International autoantibody standards, traditionally based on material obtained from plasmapheresis of single subjects, represent individual immune response and may not comprehend the heterogeneity of the general population. The anti-DFS70 autoantibody yields a characteristic dense fine speckled (DFS) nuclear pattern on indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) and speaks against autoimmunity. We propose a novel strategy for developing autoantibody reference standards, based on stepwise pooling of serum samples from hundreds of individuals with anti-DFS70 antibodies. Methods Within a 2-year period, serum samples were selected from routine HEp-2 IFA according to the following criteria: DFS HEp-2 IFA pattern at titer ≥1:640; anti-DFS70 reactivity in three analyte-specific tests (Western blot [WB], enzyme-linked immunosorbent assay [ELISA] and chemiluminescent immunoassay [CLIA]). Aliquots of individual samples were combined into progressively larger pools with stepwise validation of intermediary pools as for individual samples. Validated intermediary pools were merged into a final pool for lyophilization. Results A total of 741 validated samples yielded a 750 mL final pool that was lyophilized into thousands of 200 µL-aliquots. Reconstituted aliquots yielded the expected anti-DFS70 reactivity in ELISA, CLIA and WB, as well as high-titer DFS HEp-2 IFA pattern. The appropriate anti-DFS70 reactivity of the lyophilized pool was confirmed by seven international expert centers, using HEp-2 IFA, ELISA, WB and immunoprecipitation. Conclusions This proof-of-concept study provides an innovative and efficient strategy to build serum reference standards for autoantibody testing. The anti-DFS70 standard will integrate the panel of standards of Autoantibody Standardization Committee (ASC, www.autoab.org), contributing to education for proper assay validation and interpretation of the DFS pattern and other HEp-2 IFA patterns.

7.
Front Immunol ; 10: 745, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31024569

RESUMO

Objective: Sporadic Inclusion Body Myositis (sIBM) is an inflammatory myopathy (IIM) without a specific diagnostic biomarker until autoantibodies to the cytosolic 5'-nucleotidase 1A (NT5c1A/Mup44) were reported. The objectives of our study were to determine the sensitivity and specificity of anti-NT5c1A for sIBM, demonstrate demographic, clinical and serological predictors for anti-NT5c1A positivity and determine if anti-nuclear antibody (ANA) indirect immunofluorescence (IIF) staining on HEp-2 cells is a reliable screening method for anti-NT5c1A. Methods: Sera from sIBM patients and controls were stored at -80°C until required for analysis. IgG antibodies to NT5c1A were detected by an addressable laser bead immunoassay (ALBIA) using a full-length human recombinant protein. Autoantibodies to other autoimmune myopathy antigens (Jo-1, OJ, TIF1y, PL-12, SAE, EJ, MDA5, PL7, SRP, NXP2, MI-2) were detected by line immunoassay (LIA), chemiluminescence immunoassay (CIA) or enzyme linked immunosorbent assay (ELISA) and ANA detected by IIF on HEp-2 substrate. Demographic, clinical and serological data were obtained by chart review. Results: Forty-three patients with sIBM, 537 disease control patients with other autoimmune, degenerative and neuromuscular diseases, and 78 healthy controls were included. 48.8% (21/43) of sIBM patients were positive for anti-NT5c1A. The overall sensitivity, specificity, positive predictive value, and negative predictive value of anti-NT5c1A for sIBM were 0.49, 0.92, 0.29, and 0.96, respectively. Compared to sIBM, the frequency of anti-NT5c1A was lower in both the disease control group (8.8%, OR 0.10 [95%CI: 0.05-0.20], p < 0.0001) and in the apparently healthy control group (5.1%, OR 0.06 [95%CI: 0.02-0.18], p < 0.0001). In the univariable analysis, sIBM patients with more severe muscle weakness were more likely to be anti-NT5c1A positive (OR 4.10 [95% CI: 1.17, 14.33], p = 0.027), although this was not statistically significant (adjusted OR 4.30 [95% CI: 0.89, 20.76], p = 0.069) in the multivariable analysis. The ANA of sIBM sera did not demonstrate a consistent IIF pattern associated with anti-NT5c1A. Conclusions: Anti-NT5c1A has moderate sensitivity and high specificity for sIBM using ALBIA. The presence of anti-NT5c1A antibodies may be associated with muscle weakness. Anti-NT5c1A antibodies were not associated with a specific IIF staining pattern, hence screening using HEp-2 substrate is unlikely to be a useful predictor for presence of these autoantibodies.

8.
Ann Rheum Dis ; 78(7): 879-889, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30862649

RESUMO

The indirect immunofluorescence assay (IIFA) on HEp-2 cells is widely used for detection of antinuclear antibodies (ANA). The dichotomous outcome, negative or positive, is integrated in diagnostic and classification criteria for several systemic autoimmune diseases. However, the HEp-2 IIFA test has much more to offer: besides the titre or fluorescence intensity, it also provides fluorescence pattern(s). The latter include the nucleus and the cytoplasm of interphase cells as well as patterns associated with mitotic cells. The International Consensus on ANA Patterns (ICAP) initiative has previously reached consensus on the nomenclature and definitions of HEp-2 IIFA patterns. In the current paper, the ICAP consensus is presented on the clinical relevance of the 29 distinct HEp-2 IIFA patterns. This clinical relevance is primarily defined within the context of the suspected disease and includes recommendations for follow-up testing. The discussion includes how this information may benefit the clinicians in daily practice and how the knowledge can be used to further improve diagnostic and classification criteria.

9.
Rev. argent. reumatol ; 29(3): 6-10, set. 2018. tab
Artigo em Espanhol | LILACS | ID: biblio-977290

RESUMO

Objetivos: Estimar el efecto de los antimaláricos (AM) sobre los diferentes dominios del índice de daño SLICC (SDI). Métodos: Se estudiaron pacientes con diagnóstico clínico reciente (≤2 años) de lupus eritematoso sistémico (LES) de la cohorte GLADEL. Variable de estudio: aumento en los dominios del SDI desde el ingreso a la cohorte. Variables independientes: características sociodemográficas, clínicas, laboratorio y tratamientos. El efecto de los AM, como variable dependiente del tiempo, sobre los dominios más frecuentes del SDI (ajustado por factores de confusión) fue examinado con un modelo de regresión de Cox multivariado. Resultados: De 1466 pacientes estudiados, 1049 (72%) recibieron AM con un tiempo medio de exposición de 30 meses (Q1-Q3: 11-57) y 665 pacientes (45%) presentaron daño durante un seguimiento medio de 24 meses (Q1-Q3: 8-55); 301 eventos fueron cutáneos, 208 renales, 149 neuropsiquiátricos, 98 musculoesqueléticos, 88 cardiovasculares y 230 otros. Después de ajustar por factores de confusión, el uso de AM se asoció a un menor riesgo de daño renal (HR 0,652; IC 95%: 0,472-0,901) y en el límite de la significancia estadística (HR 0,701, IC 95%: 0,481-1,024) para el dominio neuropsiquiátrico. Conclusión: En GLADEL, el uso de AM se asoció independientemente a un menor riesgo de daño acumulado renal.


Objective: To assess the effects of antimalarials (AM) over the items of the SLICC Damage Index (SDI). Methods: Patients with recent (≤2 years) diagnosis of systemic lupus erythematosus (SLE) from the GLADEL cohort were studied. End-point: increase in items SDI since cohort entry. Independent variables (socio-demographic, clinical, laboratory and treatment) were included. The effect of AM as a time dependent variable on most frequent SDI items (adjusting for potential confounders) was examined with a multivariable Cox regression model. Results: Of the 1466 patients included in this analysis, 1049 (72%) received AM with a median exposure time of 30 months (Q1-Q3: 11-57). Damage occurred in 665 (45%) patients during a median follow-up time of 24 months (Q1-Q3: 8-55). There were 301 integument, 208 renal, 149 neuropsychiatric, 98 musculoskeletal, 88 cardiovascular and 230 others less frequently represented damages. After adjusting for potential confounders at any time during follow-up, a lower risk of renal damage (HR 0.652; 95% CI: 0.472-0.901) and borderline for neuropsychiatric damage (HR 0.701, 95% CI: 0.481-1.024) was found. Conclusion: In the GLADEL cohort, after adjustment for possible confounding factors, AM were independently associated with a reduced risk of renal damage accrual.


Assuntos
Lúpus Eritematoso Sistêmico , Antimaláricos
10.
J Hum Evol ; 120: 329-377, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29706232

RESUMO

Technological strategies of early humans are discussed in the light of a recently excavated stone tool assemblage from EF-HR, an archaeological site older than 1.33 Ma at Olduvai Gorge, Tanzania. Renewed fieldwork at EF-HR has unearthed a lithic collection containing over 2300 artefacts (including a hundred handaxes in stratigraphic position), which represents one of the largest assemblages for the early Acheulean in eastern Africa. Our technological study shows co-occurrence of two distinctive reduction sequences in the same assemblage, one aimed at obtaining small flakes and the other focused on the production of large, thick, heavy flakes that were then used as blanks for handaxe shaping. Flaking of small cores is expedient and low intensity, and knapping methods are similar to those observed in earlier Oldowan assemblages. Large Cutting Tools (LCTs) show no evidence of planform and biconvex symmetry, and shaping sequences are brief and discontinuous, indicating short use-lives for handaxes. Bifaces are rare and atypical. Recurrent morphotypes are knives, which are poorly-shaped, scraper-like, large-sized handaxes. Despite the apparent expediency of EF-HR handaxe production, a closer inspection of the interplay between debitage and façonnage stages reveals remarkably standardized procedural patterns. Large Cutting Tool blanks were produced following fixed knapping rules resulting in flakes with a specific morphology and mass distribution. Adapted to the idiosyncrasies of each blank, shaping was almost invariably imposed over the same areas in all LCTs and sought to produce morphotypes that, technologically, are remarkably identical to each other. This strongly supports the existence of mental templates and technical rules that were systematically practiced in LCT production at EF-HR, and underscore the structured nature of technological behaviour at the onset of the Acheulean in eastern Africa.

11.
J Hum Evol ; 120: 236-273, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29773229

RESUMO

HWK EE (Olduvai Gorge, Tanzania) is a late Oldowan site dated to ∼1.7 Ma that contains a large fossil and lithic assemblage. This paper reports on the technology of the recently excavated stone tool collection, over 18,000 pieces. Our results indicate that reduction sequences were generally short, flaking productivity was low, and knapping methods were largely simple and expedient, lacking the technical skills observed in other Oldowan assemblages. Conspicuous differences are observed in the chaînes opératoires of the three main raw materials used at HWK EE: the quartzite reduction sequence can be reconstructed in full at the site, most of the lava detached pieces are missing, and there is a preferential use of chert for retouched tools. This portrays a composite picture, where knapping expediency and low productivity are accompanied by raw material selectivity and consistent presence of retouched artefacts. Coexistence of these features in the same assemblage leads us to question the monolithic structure of the Oldowan techno-complex, and highlights the kaleidoscopic nature of technological strategies at Olduvai immediately before the earliest Acheulean handaxes appear in the sequence.

13.
J Hum Evol ; 120: 76-91, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29752005

RESUMO

The well-dated Pleistocene sediments at Olduvai Gorge have yielded a rich record of hominin fossils, stone tools, and vertebrate faunal remains that, taken together, provide insight to hominin behavior and paleoecology. Since 2008, the Olduvai Geochronology and Archaeology Project (OGAP) has undertaken extensive excavations in Bed II that have yielded a large collection of early Pleistocene stone tools and fossils. The strata of Lower, Middle and Upper Bed II at Olduvai Gorge capture the critical transition from Oldowan to Acheulean technology and therefore provide an opportunity to explore the possible role of biotic and abiotic change during the transition. Here, we analyze newly discovered and existing fossil teeth from Bed II sites using stable isotope and tooth wear methods to investigate the diets of large mammals. We reconstruct the dietary ecology of Bed II mammals and evaluate whether vegetation or hydroclimate shifts are associated with the technological change. Combined isotope and tooth wear data suggest most mammals were C4 grazers or mixed feeders. Carbon isotope data from bulk enamel samples indicate that a large majority of Bed II large mammals analyzed had diets comprising mostly C4 vegetation (>75% of diet), whereas only a small number of individuals had either mixed C3-C4 or mostly C3 diets (<25% C4). Mesowear generally indicates an increase of the abrasiveness of the diet between intervals IIA and IIB (∼1.66 Ma), probably reflecting increased grazing. Microwear indicates more abrasive diets in interval IIA suggesting stronger seasonal differences at the time of death during this interval. This is also supported by the intratooth isotope profiles from Equus oldowayensis molars, which suggest a possible decrease in seasonality across the transition. Neither stable isotope nor tooth wear analyses indicate major vegetation or hydrological change across the Oldowan-Acheulean transition.

14.
J Hum Evol ; 120: 19-31, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29685748

RESUMO

Archaeological excavations at EF-HR and HWK EE allow reassessment of Bed II stratigraphy within the Junction Area and eastern Olduvai Gorge. Application of Sequence Stratigraphic methods provides a time-stratigraphic framework enabling correlation of sedimentary units across facies boundaries, applicable even in those areas where conventional timelines, such as tephrostratigraphic markers, are absent, eroded, or reworked. Sequence Stratigraphically, Bed II subdivides into five major Sequences 1 to 5, all floored by major disconformities that incise deeply into the underlying succession, proving that simple "layer cake" stratigraphy is inappropriate. Previous establishment of the Lemuta Member has invalidated the use of Tuff IIA as the boundary between Lower and Middle Bed II, now redefined at the disconformity between Sequences 2 and 3, a lithostratigraphic contact underlying the succession containing the Lower, Middle, and Upper Augitic Sandstones. HWK EE site records Oldowan technology in the Lower Augitic Sandstone at the base of Sequence 3, within Middle Bed II. We suggest placement of recently reported Acheulean levels at FLK W within the Middle Augitic Sandstone, thus emphasizing that handaxes are yet to be found in earlier stratigraphic units of the Olduvai sequence. This would place a boundary between the Oldowan and Acheulean technologies at Olduvai in the Tuff IIB zone or earliest Middle Augitic Sandstone. A major disconformity between Sequences 3 and 4 at and near EF-HR cuts through the level of Tuff IIC, placing the main Acheulean EF-HR assemblage at the base of Sequence 4, within Upper rather than Middle Bed II. Sequence stratigraphic methods also yield a more highly resolved Bed II stratigraphic framework. Backwall and sidewall surveying of archaeological trenches at EF-HR and HWK EE permits definition of "Lake-parasequences" nested within the major Sequences that record downcutting of disconformities associated with lake regression, then sedimentation associated with lake transgression, capped finally by another erosional disconformity or hiatal paraconformity caused by the next lake withdrawal. On a relative time-scale rather than a vertical metre scale, the resulting Wheeler diagram framework provides a basis for recognizing time-equivalent depositional episodes and the position of time gaps at various scales. Relative timing of archaeological assemblage levels can then be differentiated at a millennial scale within this framework.

15.
Ophthalmology ; 125(9): 1444-1451, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29602570

RESUMO

PURPOSE: To assess efficacy, safety, and cost-effectiveness of adalimumab (ADA) therapy optimization in a large series of patients with uveitis due to Behçet disease (BD) who achieved remission after the use of this biologic agent. DESIGN: Open-label multicenter study of ADA-treated patients with BD uveitis refractory to conventional immunosuppressants. SUBJECTS: Sixty-five of 74 patients with uveitis due to BD, who achieved remission after a median ADA duration of 6 (range, 3-12) months. ADA was optimized in 23 (35.4%) of them. This biologic agent was maintained at a dose of 40 mg/subcutaneously/2 weeks in the remaining 42 patients. METHODS: After remission, based on a shared decision between the patient and the treating physician, ADA was optimized. When agreement between patient and physician was reached, optimization was performed by prolonging the ADA dosing interval progressively. Comparison between optimized and nonoptimized patients was performed. MAIN OUTCOME MEASURES: Efficacy, safety, and cost-effectiveness in optimized and nonoptimized groups. To determine efficacy, intraocular inflammation (anterior chamber cells, vitritis, and retinal vasculitis), macular thickness, visual acuity, and the sparing effect of glucocorticoids were assessed. RESULTS: No demographic or ocular differences were found at the time of ADA onset between the optimized and the nonoptimized groups. Most ocular outcomes were similar after a mean ± standard deviation follow-up of 34.7±13.3 and 26±21.3 months in the optimized and nonoptimized groups, respectively. However, relevant adverse effects were only seen in the nonoptimized group (lymphoma, pneumonia, severe local reaction at the injection site, and bacteremia by Escherichia coli, 1 each). Moreover, the mean ADA treatment costs were lower in the optimized group than in the nonoptimized group (6101.25 euros/patient/year vs. 12 339.48; P < 0.01). CONCLUSION: ADA optimization in BD uveitis refractory to conventional therapy is effective, safe, and cost-effective.

16.
J Hum Evol ; 120: 32-47, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29458978

RESUMO

Fossil bird data (community composition and taphonomic profiles) are used here to infer the environmental context of the Oldowan-Acheulean transitional period at Olduvai Gorge, Tanzania. This is the first comprehensive report on the Middle Bed II avifauna and includes fossils excavated by the Olduvai Geochronology and Archaeology Project (OGAP) and recently rediscovered fossils collected by Mary Leakey. Crane, ibis, darter, owl, raptor, crow, and vulture are reported from Bed II for the first time. The presence of these taxa, absent earlier in this Bed, point to a general opening and drying of the landscape with grassland and open woodland expansion. Taxa associated with dense, emergent wetland vegetation, such as dabbling ducks and rails, are uncommon and less diverse than earlier in Bed II. This suggests more mature wetlands with clearer waters. Cormorants continue to be common, but are less diverse. Cormorants and other roosting taxa provide evidence of trees in the area. Compared to lowermost Bed II, the Middle to Upper Bed II landscape is interpreted here as more open and drier (but not necessarily more arid), with matured wetlands, scattered trees, and a greater expansion of grasslands.

18.
J Hum Evol ; 120: 378-401, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29331229

RESUMO

The lithic assemblages at the Oldowan-Acheulean transition in Bed II of Olduvai Gorge, Tanzania, represent a wide variety of raw materials reflecting both the diversity of volcanic, metamorphic, and sedimentary source materials available in the Olduvai basin and surroundings and the preferences of the tool-makers. A geochemical and petrographic systematic analysis of lava-derived archaeological stone tools, combined with textural and mineralogical characterization of quartzite, chert, and other metamorphic and sedimentary raw materials from two Middle and Upper Bed II sites, has enabled us to produce a comprehensive dataset and characterization of the rocks employed by Olduvai hominins, which is used here to establish a referential framework for future studies on Early Stone Age raw material provenancing. The use of rounded blanks for most lava-derived artifacts demonstrates that hominins were accessing lava in local stream channels. Most quartzite artifacts appear to derive from angular blocks, likely acquired at the source (predominantly Naibor Soit hill), though some do appear to be manufactured from stream-transported quartzite blanks. Raw material composition of the EF-HR assemblage indicates that Acheulean hominins selected high-quality lavas for the production of Large Cutting Tools. On the other hand, the HWK EE lithic assemblage suggests that raw material selectivity was not entirely based on rock texture, and other factors, such as blank shape and availability of natural angles suitable for flaking, played a major role in Oldowan reduction sequences.

19.
J Hum Evol ; 120: 48-75, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29191415

RESUMO

Eight years of excavation work by the Olduvai Geochronology and Archaeology Project (OGAP) has produced a rich vertebrate fauna from several sites within Bed II, Olduvai Gorge, Tanzania. Study of these as well as recently re-organized collections from Mary Leakey's 1972 HWK EE excavations here provides a synthetic view of the faunal community of Olduvai during Middle Bed II at ∼1.7-1.4 Ma, an interval that captures the local transition from Oldowan to Acheulean technology. We expand the faunal list for this interval, name a new bovid species, clarify the evolution of several mammalian lineages, and record new local first and last appearances. Compositions of the fish and large mammal assemblages support previous indications for the dominance of open and seasonal grassland habitats at the margins of an alkaline lake. Fish diversity is low and dominated by cichlids, which indicates strongly saline conditions. The taphonomy of the fish assemblages supports reconstructions of fluctuating lake levels with mass die-offs in evaporating pools. The mammals are dominated by grazing bovids and equids. Habitats remained consistently dry and open throughout the entire Bed II sequence, with no major turnover or paleoecological changes taking place. Rather, wooded and wet habitats had already given way to drier and more open habitats by the top of Bed I, at 1.85-1.80 Ma. This ecological change is close to the age of the Oldowan-Acheulean transition in Kenya and Ethiopia, but precedes the local transition in Middle Bed II. The Middle Bed II large mammal community is much richer in species and includes a much larger number of large-bodied species (>300 kg) than the modern Serengeti. This reflects the severity of Pleistocene extinctions on African large mammals, with the loss of large species fitting a pattern typical of defaunation or 'downsizing' by human disturbance. However, trophic network (food web) analyses show that the Middle Bed II community was robust, and comparisons with the Serengeti community indicate that the fundamental structure of food webs remained intact despite Pleistocene extinctions. The presence of a generalized meat-eating hominin in the Middle Bed II community would have increased competition among carnivores and vulnerability among herbivores, but the high generality and interconnectedness of the Middle Bed II food web suggests this community was buffered against extinctions caused by trophic interactions.

20.
J Hum Evol ; 120: 140-202, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29153333

RESUMO

This paper reports the results of renewed fieldwork at the HWK EE site (Olduvai Gorge, Tanzania). HWK EE is positioned across the boundary between Lower and Middle Bed II, a crucial interval for studying the emergence of the Acheulean at Olduvai Gorge. Our excavations at HWK EE have produced one of the largest collections of fossils and artefacts from any Oldowan site, distributed across several archaeological units and a large excavation surface in four separate trenches that can be stratigraphically correlated. Here we present the main stratigraphic and archaeological units and discuss site formation processes. Results show a great density of fossils and stone tools vertically through two stratigraphic intervals (Lemuta and Lower Augitic Sandstone) and laterally across an area of around 300 m2, and highlight the confluence of biotic and abiotic agents in the formation of the assemblage. The large size and diversity of the assemblage, as well as its good preservation, qualify HWK EE as a reference site for the study of the late Oldowan at Olduvai Gorge and elsewhere in Africa. In addition, the description of the stratigraphic and archaeological sequence of HWK EE presented in this paper constitutes the foundation for further studies on hominin behavior and paleoecology in Lower and Middle Bed II.

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