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1.
Front Neurol ; 10: 838, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31440201

RESUMO

Objective: Pipeline embolization devices (PEDs) are widely used to exclude intracranial aneurysms from their parent arteries. Side branches covered by PEDs, however, sometimes experience occlusion and related symptoms. Thus, predictors of branch occlusion and the patency and clinical outcomes of these branches are concerning. Methods: We conducted a retrospective review of consecutive patients who had been treated with PEDs in our institution during 2015-2018 to identify those in whom one or more branches were involved. Pretreatment and follow-up angiograms were assessed to determine patency of the involved branches. Demographic and clinical data, treatment strategies, and comorbidities were collected to investigate their relations with branch occlusion. Results: Altogether, 173 branches [24 (13.9%) occluded), 29 (16.8%) with diminished flow] in 126 patients were studied. Five patients (OphA involved) presented with blurred vision and 1 patient (ACA involved) presented with headache. None of the other patients had neurologic complications or clinical strokes related to branch occlusion. Multivariate analysis identified that small PED diameter [p = 0.003, odds ratio (OR) = 0.168], branches arising from the aneurysm (p = 0.004, OR = 6.614), and involvement of the anterior cerebral artery (ACA) (p < 0.001, OR = 25.656) significantly predicted branch occlusion. Conclusion: Branch occlusion rate after PED deployment was low and most occlusions was asymptomatic. Branches with rich collateral supply were more likely to occlude, especially the ACA. Smaller PED diameter, branches arising from the aneurysm, and ACA involvement were significant predictors of branch occlusion after PED treatment.

2.
Front Neurol ; 10: 658, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31275237

RESUMO

Objective: Flow diverter devices are increasingly used in the treatment of posterior circulation aneurysms, sometimes necessarily involving ostia of side branches and perforators. The aim of this study was to identify the hemodynamic influence of flow diverters on side branches and perforators of the posterior circulation. Methods: We performed a retrospective study of consecutive patients treated by a flow diverter device for posterior circulation aneurysms with anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA) involvement. Computational fluid dynamics (CFD) were used to discern hemodynamic changes of branches after deployment of the flow diverter. Results: We studied 18 branches from 17 patients (mean age, 50.72 ± 8.17 years). No branches were occluded on immediate angiography and later follow-up. Average flow velocity in aneurysms decreased from 0.077 ± 0.065 m/s to 0.025 ± 0.025 m/s (p < 0.01). Average flow velocity in branch ostia decreased from 0.29 ± 0.14 m/s to 0.27 ± 0.16 m/s (p = 0.189). The difference in flow velocity reduction ratio between aneurysms and branches was statistically significant (68.8 vs. 9.5%; p < 0.001). The mean pressure in branch ostia increased from 10,717.4 ± 489.0 to 10,859.0 ± 643.4 Pa (p < 0.01). Conclusion: While a flow diverter device is capable of slowing down aneurysmal inflow, it is unable to block the flow into branches and perforators when used in the treatment of posterior circulation aneurysms; flow velocity in branches even increased in some cases. With a low branch occlusion ratio, it may be acceptable to cover posterior circulation branches and perforators if unavoidable.

3.
J Transl Med ; 17(1): 160, 2019 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-31096981

RESUMO

BACKGROUND: Flow diverter devices are increasingly used for endovascular treatment of internal carotid artery aneurysms. Treatment of ophthalmic segment aneurysms with flow diverter devices also includes coverage of the ophthalmic artery but may result in complications. It is unclear, however, whether these devices mechanically block blood flow in the ophthalmic artery. Also unclear is the relationship between deployment of a flow diverter device and post-treatment occlusion. We studied hemodynamic changes in the ophthalmic artery after deployment of a flow diverter device to determine the relationship between those changes and post-stent occlusion of the artery. METHODS: We analyzed hemodynamic modifications in the ophthalmic artery in 21 patients (19 women, 2 men; mean age 53.43 ± 7.32 years) treated by a single pipeline embolization device. Patient-specific geometries were determined from three-dimensional digital subtraction angiography and the stenting process was simulated. Computational fluid dynamics technology was used to analyze the change in ophthalmic artery hemodynamics. We compared pre-treatment and post-treatment flow velocity of the ophthalmic artery. RESULTS: Among the 21 patients with aneurysms located in the ophthalmic segment, no ophthalmic artery occlusion was found during immediate or follow-up angiography. Post-stent flow velocity in the ophthalmic artery decreased from 0.35 ± 0.19 to 0.33 ± 0.20 m/s, with the difference not being statistically significant (P = 0.106). CONCLUSION: Our results showed no significant change in ophthalmic artery blood flow after pipeline embolization device deployment. Hence, post-stent occlusion of the ophthalmic artery could not be explained by reduced blood flow. Delayed thrombosis and neointimal formation maybe the keys to ophthalmic artery occlusion and need further investigation.

4.
Science ; 359(6374): 456-459, 2018 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-29371468

RESUMO

To date, the earliest modern human fossils found outside of Africa are dated to around 90,000 to 120,000 years ago at the Levantine sites of Skhul and Qafzeh. A maxilla and associated dentition recently discovered at Misliya Cave, Israel, was dated to 177,000 to 194,000 years ago, suggesting that members of the Homo sapiens clade left Africa earlier than previously thought. This finding changes our view on modern human dispersal and is consistent with recent genetic studies, which have posited the possibility of an earlier dispersal of Homo sapiens around 220,000 years ago. The Misliya maxilla is associated with full-fledged Levallois technology in the Levant, suggesting that the emergence of this technology is linked to the appearance of Homo sapiens in the region, as has been documented in Africa.


Assuntos
Evolução Biológica , Migração Humana/história , África , Cavernas , Dentição , Fósseis , História Antiga , Humanos , Israel , Maxila , Tecnologia/história
5.
Am J Phys Anthropol ; 164(4): 679-701, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29068047

RESUMO

OBJECTIVES: A nearly complete hominin fossil cranium from Dali in Shaanxi Province, China was excavated in 1978. We update and expand on previous research by providing a multivariate analysis of the specimen relative to a large sample of Middle and Late Pleistocene hominins. MATERIALS AND METHODS: We apply principal components analysis, discriminant function analysis, and a method of assessing group membership based on a soft independent model of class analogy (SIMCA) to the study of Dali's cranial morphology. We evaluate Dali's affinities within the context of Middle and Late Pleistocene Homo patterns of craniofacial morphology. RESULTS: When just the facial skeleton is considered, Dali aligns with Middle Paleolithic H. sapiens and is clearly more derived than African or Eurasian Middle Pleistocene Homo. When just the neurocranium is considered, Dali is most similar to African and Eastern Eurasian but not Western European Middle Pleistocene Homo. When both sets of variables are considered together, Dali exhibits a unique morphology that is most closely aligned with the earliest H. sapiens from North Africa and the Levant. DISCUSSION: These results add perspective to our previous view of as Dali a "transitional" form between Chinese H. erectus and H. sapiens. Athough no taxonomic allocation is appropriate at this time for Dali, it appears to represent a population that played a more central role in the origin of Chinese H. sapiens. Dali's affinities can be understood in the context of Wu's Continuity with Hybridization scenario and a braided-stream network model of gene flow. Specifically, we propose that Pleistocene populations in China were shaped by periods of isolated evolutionary change within local lineages at certain times, and gene flow between local lineages or between Eastern and Western Eurasia, and Africa at other times, resulting in contributions being made in different capacities to different regions at different times.


Assuntos
Evolução Biológica , Hominidae/anatomia & histologia , Crânio/anatomia & histologia , África , Animais , Antropologia Física , China , Fósseis , Fluxo Gênico , Hominidae/genética , Análise Multivariada
6.
J Hum Evol ; 88: 54-69, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26553818

RESUMO

The Hexian calvarium is one of the most complete and well-preserved Homo erectus fossils ever found in east Asia, apart from the Zhoukoudian specimens. Various methods bracket the age of the Hexian fossil to between 150 and 412 ka (thousands of years ago). The Hexian calvarium has been considered to be H. erectus given its morphological similarities to Zhoukoudian and Javan H. erectus. However, discussion continues regarding the affinities of the Hexian specimen with other H. erectus fossils. The arguments mainly focus on its relationships to other Asian H. erectus fossils, including those from both China and Java. To better determine the affinities of the Hexian cranium, our study used 3D landmark and semilandmark geometric morphometric techniques and multivariate statistical analyses to quantify the shape of the neurocranium and to compare the Hexian cranium to other H. erectus specimens. The results of this study confirmed the morphological similarities between Hexian and Chinese H. erectus in overall morphology, and particularly in the structure of the frontal bone and the posterior part of the neurocranium. Although the Hexian specimen shows the strongest connection to Chinese H. erectus, the morphology of the lateral neurocranium resembles early Indonesian H. erectus specimens, possibly suggesting shared common ancestry or gene flow from early Indonesian populations. Overall cranial and frontal bone morphology are strongly influenced by geography. Although geographically intermediate between Zhoukoudian and Indonesian H. erectus, the Hexian specimen does not form part of an obvious morphological gradient with regard to overall cranial shape.


Assuntos
Evolução Biológica , Fósseis/anatomia & histologia , Hominidae/anatomia & histologia , Crânio/anatomia & histologia , Animais , Cefalometria , China , Hominidae/classificação , Masculino , Filogenia
7.
Small ; 11(6): 694-701, 2015 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-25236419

RESUMO

Size-dependent nonlinear optical properties of modification-free transition metal dichalcogenide (TMD) nanosheets are reported, including MoS2 , WS2 , and NbSe2 . Firstly, a gradient centrifugation method is demonstrated to separate the TMD nanosheets into different sizes. The successful size separation allows the study of size-dependent nonlinear optical properties of nanoscale TMD materials for the first time. Z-scan measurements indicate that the dispersion of MoS2 and WS2 nanosheets that are 50-60 nm thick leads to reverse saturable absorption (RSA), which is in contrast to the saturable absorption (SA) seen in the thicker samples. Moreover, the NbSe2 nanosheets show no size-dependent effects because of their metallic nature. The mechanism behind the size-dependent nonlinear optical properties of the semiconductive TMD nanosheets is revealed by transient transmission spectra measurements.

8.
Am J Phys Anthropol ; 150(1): 141-57, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23283667

RESUMO

In 1978, a nearly complete hominin fossil cranium was recovered from loess deposits at the site of Dali in Shaanxi Province, northwestern China. It was subsequently briefly described in both English and Chinese publications. Here we present a comprehensive univariate and nonmetric description of the specimen and provide comparisons with key Middle Pleistocene Homo erectus and non-erectus hominins from Eurasia and Africa. In both respects we find affinities with Chinese H. erectus as well as African and European Middle Pleistocene hominins typically referred to as Homo heidelbergensis. Specifically, the Dali specimen possesses a low cranial height, relatively short and arched parietal bones, an angled occipital bone, and a nonprominent articular tubercle relative to the preglenoid surface all of which distinguish it from Afro/European Middle Pleistocene Homo and align it with Asian H. erectus. At the same time, it displays a more derived morphology of the supraorbital torus and supratoral sulcus and a thinner tympanic plate than H. erectus, a relatively long upper (lambda-inion) occipital plane with a clear separation of inion and opisthocranion, and an absolute and relative increase in brain size, all of which align it with African and European Middle Pleistocene Homo. Finally, traits such as the form of the frontal keel and the relatively short, broad midface align Dali specifically with other Chinese specimens from the Middle Pleistocene and Late Pleistocene, including H. erectus, and differentiate these from the Afro/European specimens of this time period.


Assuntos
Fósseis , Hominidae/anatomia & histologia , Crânio/anatomia & histologia , Animais , Antropologia Física , China , Paleopatologia , Crânio/patologia
9.
Proc Natl Acad Sci U S A ; 107(45): 19201-6, 2010 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-20974952

RESUMO

The 2007 discovery of fragmentary human remains (two molars and an anterior mandible) at Zhirendong (Zhiren Cave) in South China provides insight in the processes involved in the establishment of modern humans in eastern Eurasia. The human remains are securely dated by U-series on overlying flowstones and a rich associated faunal sample to the initial Late Pleistocene, >100 kya. As such, they are the oldest modern human fossils in East Asia and predate by >60,000 y the oldest previously known modern human remains in the region. The Zhiren 3 mandible in particular presents derived modern human anterior symphyseal morphology, with a projecting tuber symphyseos, distinct mental fossae, modest lateral tubercles, and a vertical symphysis; it is separate from any known late archaic human mandible. However, it also exhibits a lingual symphyseal morphology and corpus robustness that place it close to later Pleistocene archaic humans. The age and morphology of the Zhiren Cave human remains support a modern human emergence scenario for East Asia involving dispersal with assimilation or populational continuity with gene flow. It also places the Late Pleistocene Asian emergence of modern humans in a pre-Upper Paleolithic context and raises issues concerning the long-term Late Pleistocene coexistence of late archaic and early modern humans across Eurasia.


Assuntos
Fósseis , Paleodontologia/métodos , China , Extremo Oriente , Humanos , Mandíbula , Dente Molar
10.
Am J Phys Anthropol ; 127(3): 253-62, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15584056

RESUMO

The morphology and affinities of early and middle Pleistocene Homo erectus in East Asia have been explored since the late nineteenth century. A fragmentary hominid cranium (Nanjing no.1) recovered in Tangshan near Nanjing, China bears directly on these issues. In the present study, the morphological features of Nanjing no.1 are described and compared with Homo erectus from both Eurasia and Africa. Our results indicate that this middle Pleistocene hominid fossil should be referred to as Homo erectus. The sharing of typical Homo erectus features with African and European counterparts demonstrates that Homo erectus is a widely distributed lineage that evolved during the million years after its Pliocene origins. The differences between Nanjing no.1 and Zhoukoudian suggest certain level of regional variation in East Asian Homo erectus.


Assuntos
Fósseis , Hominidae/anatomia & histologia , Modelos Anatômicos , Crânio/anatomia & histologia , Animais , Cefalometria , China , Feminino , Humanos , Análise de Componente Principal
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