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1.
Nature ; 507(7492): 350-3, 2014 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-24522537

RESUMO

Inference of colour patterning in extinct dinosaurs has been based on the relationship between the morphology of melanin-containing organelles (melanosomes) and colour in extant bird feathers. When this relationship evolved relative to the origin of feathers and other novel integumentary structures, such as hair and filamentous body covering in extinct archosaurs, has not been evaluated. Here we sample melanosomes from the integument of 181 extant amniote taxa and 13 lizard, turtle, dinosaur and pterosaur fossils from the Upper-Jurassic and Lower-Cretaceous of China. We find that in the lineage leading to birds, the observed increase in the diversity of melanosome morphologies appears abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs. Similarly, mammals show an increased diversity of melanosome form compared to all ectothermic amniotes. In these two clades, mammals and maniraptoran dinosaurs including birds, melanosome form and colour are linked and colour reconstruction may be possible. By contrast, melanosomes in lizard, turtle and crocodilian skin, as well as the archosaurian filamentous body coverings (dinosaur 'protofeathers' and pterosaur 'pycnofibres'), show a limited diversity of form that is uncorrelated with colour in extant taxa. These patterns may be explained by convergent changes in the key melanocortin system of mammals and birds, which is known to affect pleiotropically both melanin-based colouration and energetic processes such as metabolic rate in vertebrates, and may therefore support a significant physiological shift in maniraptoran dinosaurs.


Assuntos
Evolução Biológica , Dinossauros/fisiologia , Plumas , Melanossomas/fisiologia , Pigmentação , Jacarés e Crocodilos/anatomia & histologia , Animais , Aves/anatomia & histologia , China , Extinção Biológica , Plumas/citologia , Fósseis , Cor de Cabelo , Tegumento Comum/anatomia & histologia , Tegumento Comum/fisiologia , Lagartos/anatomia & histologia , Mamíferos/anatomia & histologia , Melaninas/metabolismo , Melanossomas/ultraestrutura , Pigmentação da Pele , Tartarugas/anatomia & histologia
2.
Nature ; 500(7461): 163-7, 2013 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-23925238

RESUMO

The earliest evolution of mammals and origins of mammalian features can be traced to the mammaliaforms of the Triassic and Jurassic periods that are extinct relatives to living mammals. Here we describe a new fossil from the Middle Jurassic that has a mandibular middle ear, a gradational transition of thoracolumbar vertebrae and primitive ankle features, but highly derived molars with a high crown and multiple roots that are partially fused. The upper molars have longitudinal cusp rows that occlude alternately with those of the lower molars. This specialization for masticating plants indicates that herbivory evolved among mammaliaforms, before the rise of crown mammals. The new species shares the distinctive dental features of the eleutherodontid clade, previously represented only by isolated teeth despite its extensive geographic distribution during the Jurassic. This eleutherodontid was terrestrial and had ambulatory gaits, analogous to extant terrestrial mammals such as armadillos or rock hyrax. Its fur corroborates that mammalian integument had originated well before the common ancestor of living mammals.


Assuntos
Adaptação Biológica , Evolução Biológica , Fósseis , Animais , Osso e Ossos/anatomia & histologia , China , Mamíferos , Filogenia , Especificidade da Espécie , Dente/anatomia & histologia
3.
World J Surg Oncol ; 13: 97, 2015 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-25886608

RESUMO

BACKGROUND: Magnetic resonance imaging (MRI) plays an irreplaceable role in the preoperative diagnosis of glioma, and its imaging features are the base of making treatment decisions in patients with glioma, but it is still controversial whether peritumoral edema shown by MRI from preoperative routine scans are associated with patient survival. The aim of this study was to assess the prognostic value of preoperative MRI features in patients with glioblastoma. METHODS: A retrospective review of 87 patients with newly diagnosed supratentorial glioblastoma was performed using medical records and MRI data from routine scans. The Kaplan-Meier method and COX proportional hazard model were applied to evaluate the prognostic impact on overall survival of pretreatment MRI features (including peritumoral edema, edema shape, necrosis, cyst, enhancement, tumor crosses midline, edema crosses midline, and tumor size). RESULTS: In addition to patient age, Karnofsky performance status (KPS) and postoperative chemoradiotherapy, peritumoral edema extent and necrosis on preoperative MRI were independent prognostic indicator for poor survival. Furthermore, patients with two unfavorable conditions (major edema and necrosis) had a shorter overall survival compared with the remainder. CONCLUSIONS: Our data confirm that peritumoral edema extent and necrosis are helpful for predicting poor clinical outcome in glioblastoma. These features were easy to determine from routine MRI scans postoperatively and therefore could provide a certain instructive significance for clinical activities.


Assuntos
Edema Encefálico/patologia , Neoplasias Encefálicas/complicações , Glioblastoma/complicações , Imageamento por Ressonância Magnética/métodos , Adulto , Idoso , Edema Encefálico/etiologia , Edema Encefálico/mortalidade , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/cirurgia , Feminino , Seguimentos , Glioblastoma/mortalidade , Glioblastoma/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
4.
BMC Evol Biol ; 14: 77, 2014 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-24707892

RESUMO

BACKGROUND: Manchurochelys manchoukuoensis is an emblematic turtle from the Cretaceous Yixian Formation of Liaoning, China, a geological rock unit that is famous for yielding perfectly preserved skeletons of fossil vertebrates, including that of feathered dinosaurs. Manchurochelys manchoukuoensis was one of the first vertebrates described from this fauna, also known as the Jehol Biota. The holotype was lost during World War II and only one additional specimen has been described since. Manchurochelys manchoukuoensis is a critical taxon for unraveling the phylogenetic relationships of Cretaceous pancryptodires from Asia, a group that is considered to be of key importance for the origin of crown-group hidden-neck turtles (Cryptodira). RESULTS: A new specimen of Manchurochelys manchoukuoensis is described here from the Jiufotang Formation of Qilinshan, Chifeng, Inner Mongolia, China. This is the third specimen described and expands the range of this taxon from the Yixian Formation of the Fuxin-Yixian Basin in Liaoning to the Jiufotang Formation of the Chifeng-Yuanbaoshan Basin. A possible temporal extension of the range is less certain. The new finding adds to our understanding of the morphology of this taxon and invites a thorough revision of the phylogeny of Macrobaenidae, Sinemydidae, and closely allied forms. CONCLUSIONS: Our comprehensive phylogenetic analyses of Cretaceous Asian pancryptodires yielded two main competing hypotheses: in the first these taxa form a paraphyletic grade, whereas in the second they form a monophyletic clade. The inclusion of problematic tree changing taxa, such as Panpleurodires (stem + crown side-neck turtles) has a major influence on the phylogenetic relationships of Sinemydidae and closely allied forms. Manchurochelys manchoukuoensis nests within Sinemydidae together with Sinemys spp. and Dracochelys bicuspis in the majority of our analyses.


Assuntos
Fósseis , Filogenia , Tartarugas/anatomia & histologia , Tartarugas/classificação , Exoesqueleto , Animais , Osso e Ossos/anatomia & histologia , China
5.
Cancer Invest ; 32(2): 31-6, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24328555

RESUMO

To systematically review the efficacy/safety of radiotherapy/temozolomide (TMZ) vs. radiotherapy for treating glioblastoma (GBM), Medline, Current Contents, and Cochrane database were searched. Five studies were reviewed. Median survival ranged from 9.4 to 19.0 months (radiotherapy/TMZ) vs. 7.3-17.1 months (radiotherapy). Survival ranged from 80.2% to 95.0% (radiotherapy/TMZ) vs. 8.3-84.2% (radiotherapy) at 0.5 years and from 20.0% to 61.1% (radiotherapy/TMZ) vs. 5.0-50.6% (radiotherapy) at 1 year. Median progression-free survival (PFS) ranged from 5.5 to 13.0 months (radiotherapy/TMZ) vs. 4.4-7.6 months (radiotherapy). PFS rates at 0.5 years ranged from 53.9-78.0% (radiotherapy/TMZ) vs. 53.9-78.0% (radiotherapy). Radiotherapy/TMZ provides better survival outcomes than radiotherapy alone in treating GBM.


Assuntos
Antineoplásicos Alquilantes/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Neoplasias do Sistema Nervoso Central/radioterapia , Dacarbazina/análogos & derivados , Glioblastoma/tratamento farmacológico , Glioblastoma/radioterapia , Quimiorradioterapia , Dacarbazina/uso terapêutico , Intervalo Livre de Doença , Glioblastoma/patologia , Humanos , Temozolomida
6.
BMC Evol Biol ; 13: 203, 2013 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-24053145

RESUMO

BACKGROUND: Most turtles from the Middle and Late Jurassic of Asia are referred to the newly defined clade Xinjiangchelyidae, a group of mostly shell-based, generalized, small to mid-sized aquatic froms that are widely considered to represent the stem lineage of Cryptodira. Xinjiangchelyids provide us with great insights into the plesiomorphic anatomy of crown-cryptodires, the most diverse group of living turtles, and they are particularly relevant for understanding the origin and early divergence of the primary clades of extant turtles. RESULTS: Exceptionally complete new xinjiangchelyid material from the ?Qigu Formation of the Turpan Basin (Xinjiang Autonomous Province, China) provides new insights into the anatomy of this group and is assigned to Xinjiangchelys wusu n. sp. A phylogenetic analysis places Xinjiangchelys wusu n. sp. in a monophyletic polytomy with other xinjiangchelyids, including Xinjiangchelys junggarensis, X. radiplicatoides, X. levensis and X. latiens. However, the analysis supports the unorthodox, though tentative placement of xinjiangchelyids and sinemydids outside of crown-group Testudines. A particularly interesting new observation is that the skull of this xinjiangchelyid retains such primitive features as a reduced interpterygoid vacuity and basipterygoid processes. CONCLUSIONS: The homology of basipterygoid processes is confidently demonstrated based on a comprehensive review of the basicranial anatomy of Mesozoic turtles and a new nomenclatural system is introduced for the carotid canal system of turtles. The loss of the basipterygoid process and the bony enclosure of the carotid circulation system occurred a number of times independently during turtle evolution suggesting that the reinforcement of the basicranial region was essential for developing a rigid skull, thus paralleling the evolution of other amniote groups with massive skulls.


Assuntos
Evolução Biológica , Tartarugas/anatomia & histologia , Tartarugas/genética , Animais , China , Filogenia , Esqueleto , Tartarugas/classificação , Tartarugas/fisiologia
7.
Naturwissenschaften ; 99(11): 925-35, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23086389

RESUMO

A spectacular new terrestrial Konzentratlagerstätte is introduced from the Turpan Basin of Xinjiang, China that probably belongs to the late Middle Jurassic Qigu Formation. It contains a mass accumulation of "xinjiangchelyid" turtles preliminarily identified as Annemys sp. In the zone with the highest turtle concentration, complete and articulated turtle skeletons are tightly packed at a density of up to 36 turtles per square meter. The fossiliferous layer is thickened here and shows an erosional base. This high concentration zone outcrops approximately 10 m in length and shows no decrease in turtle density after exposing 2 m of the layer into the hillside. Adjacent is a more expansive zone of at least 10 m by 30 m. In this region, the fossiliferous layer is evenly thick, and approximately five, fully disarticulated turtles are present per square meter. A conservatively estimated 1,800 turtles may, therefore, have been deposited at this site. It is likely that these aquatic turtles gathered in a retreating water hole in a riverine environment during a drought, much as some aquatic turtles will do today, but perished when the habitat dried up completely. A following catastrophic rainfall event caused a debris flow, possibly channelized in a dry river bed, which transported complete turtles, disarticulated turtles, and mudstone clasts and deposited them after a short distance. This taphonomic model is consistent with previous environmental reconstructions of the Turpan Basin during the late Middle Jurassic in predicting the episodic breakdown of regional monsoonal circulation resulting in a seasonally dry climate with severe episodic droughts.


Assuntos
Osso e Ossos , Fósseis , Tartarugas , Animais , China , Sedimentos Geológicos , Tartarugas/anatomia & histologia , Tartarugas/classificação
8.
Sci Rep ; 12(1): 10159, 2022 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-35715498

RESUMO

The tapejarid pterosaurs flourished in the Jehol Biota with an abundance of immature individuals and a rarity of individuals at skeletal maturity. Most of these individuals plot well on an ontogenetic series based on the proportions of limb elements, but this has lacked histological evidence until now. Here, a new wing skeleton of Sinopterus was thin-sectioned to provide the first histological data about the ontogeny of the Jehol tapejarids. Histologically, the new specimen is an immature individual at a late juvenile stage prior to sexual maturity. It is grouped with medium-sized and medium-crested individuals, which are distinct from the small-sized and crestless individuals as well as the rare large-sized and large-crested individuals at skeletal maturity, supporting the presence of the premaxillary crest as an ontogenetic feature in the Jehol tapejarids. Furthermore, this histology indicates that the largest skeletally immature individuals might have reached the sexual maturity. Enigmatically, there is a size gap between sexual and skeletal maturity, which is at about 79% of the large size, implying a ontogenetic strategy comparable with Pteranodon and possibly with the Brazilian tapejarid Caiuajara. This size gap is consistent with lack of the larger sexually mature individuals in the Jehol Biota, which is hypothesized to be a migratory habitat for the Jehol tapejarids.


Assuntos
Fósseis , Esqueleto , Animais , Biota , Brasil , Humanos
9.
J Neurol Surg A Cent Eur Neurosurg ; 81(2): 155-162, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31550736

RESUMO

BACKGROUND: Basal ganglia hemorrhage (BGH) is a devastating neurologic disease with high morbidity and mortality, and its management is still controversial. We evaluated the effectiveness of surgical treatments for BGH and investigated computed tomography (CT) imaging features affecting the hematoma evacuation rate (ER) in patients treated with neuroendoscopic surgery. MATERIALS AND METHODS: A total of 104 BGH patients who underwent craniotomy, burr-hole drainage, or neuroendoscopic surgery were analyzed retrospectively. Clinical characteristics, imaging features, and postoperative complications were compared. Univariate and multivariate regression analyses were applied to identify imaging factors associated with ER. RESULTS: A significant difference in ER was observed: 78.4% in patients treated with neuroendoscopic surgery, 33.6% in patients treated with burr-hole drainage, and 82.5% in patients treated with craniotomy (p < 0.001). Similar results were observed for operative time (p < 0.001). Five cases (12.5%) of rebleeding were found in patients treated with burr-hole drainage (p = 0.020). No significant difference was found for pneumonia, intracranial infection, gastrointestinal bleeding, hospital mortality, hospital stay, expenses, 3-day Glasgow Coma Scale (GCS) scores after surgery, or GCS at discharge. The CT imaging feature, the island sign (p = 0.004), was observed as an independent factor correlated with lower ER for neuroendoscopic surgery. CONCLUSIONS: The benefits and drawbacks of surgical treatments confirmed they have their own indications, and neuroendoscopic surgery may be relatively beneficial for BGH treatment. The island sign was an independent factor affecting ER for neuroendoscopic surgery. Therefore, comprehensive assessment of clinical data, especially the island sign, should be performed preoperatively in BGH patients.


Assuntos
Hemorragia dos Gânglios da Base/diagnóstico por imagem , Hemorragia dos Gânglios da Base/cirurgia , Drenagem/métodos , Endoscopia/métodos , Procedimentos Neurocirúrgicos/métodos , Idoso , Craniotomia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neuroendoscopia , Cuidados Pós-Operatórios , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Resultado do Tratamento
10.
Science ; 365(6450): 276-279, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31320539

RESUMO

We report a new Jurassic docodontan mammaliaform found in China that is preserved with the hyoid bones. Its basihyal, ceratohyal, epihyal, and thyrohyal bones have mobile joints and are arranged in a saddle-shaped configuration, as in the mobile linkage of the hyoid apparatus of extant mammals. These are fundamentally different from the simple hyoid rods of nonmammaliaform cynodonts, which were likely associated with a wide, nonmuscularized throat, as seen in extant reptiles. The hyoid apparatus provides a framework for the larynx and for the constricted, muscularized esophagus, crucial for transport and powered swallowing of the masticated food and liquid in extant mammals. These derived structural components of hyoids evolved among early diverging mammaliaforms, before the disconnection of the middle ear from the mandible in crown mammals.


Assuntos
Osso Hioide/anatomia & histologia , Mamíferos/anatomia & histologia , Mamíferos/classificação , Animais , Orelha Média/anatomia & histologia , Esôfago/anatomia & histologia , Laringe/anatomia & histologia , Mandíbula/anatomia & histologia , Filogenia
11.
PeerJ ; 7: e6229, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30671300

RESUMO

Chronostratigraphic correlation of terrestrial Early Cretaceous biotas in China is highly problematic due to the lack of marine deposits, few absolute dates, and limited number of index fossils. This often leaves vertebrate faunas as one of the few potential tools for a preliminary biostratigraphy. Taxonomic identity of fragmentary fossils is, however, often uncertain and many faunas are insufficiently sampled. Turtles are one of the most common elements of Early Cretaceous biotas of Asia and their skeleton is frequently preserved more completely than that of other vertebrates- they yet receive little attention from vertebrate paleontologists. We here record the presence of the sinemydid turtle Ordosemys leios from the Lower Cretaceous Mengyin Formation of Shandong Province, China, best known for the first dinosaurs and Mesozoic turtles described from the country. Ordosemys is the third turtle reported from the Mengyin Formation along with Sinemys lens and Sinochelys applanata and the only other formation where Ordosemys is known to co-occur with Sinemys is the Luohandong Formation of the Ordos Basin (Inner Mongolia), the type and so far only horizon of Ordosemys leios. The presence of the crocodyliform Shantungosuchus may further define a fauna that is so far only known from these two formations. The stratigraphic position of the Luohandong Formation is poorly controlled and it has been placed anywhere between the Valanginian and Aptian. Published absolute dates from the Mengyin Formation and the numerous shared vertebrate and invertebrate taxa (now also including turtles) implies a Valanginian-early Hauterivian age for the Luohandong Formation-in contrast to late Hauterivian-Albian as previously proposed using the temporal distribution of Psittacosaurus. The new specimen of Ordosemys leios preserves the only known manus of this species and ecomorphological analysis of limb proportions implies that it was a less capable swimmer compared to Ordosemys liaoxiensis coming from the younger Jehol Biota.

12.
PeerJ ; 6: e5371, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30065899

RESUMO

Hyperphalangy is a rare condition in extant aquatic turtles, and mainly limited to soft-shelled turtles. Here we report a new freshwater turtle, Jeholochelys lingyuanensis gen. et sp. nov. from the Early Cretaceous Jehol Biota of western Liaoning, China. This new turtle is characterized by a hyperphalangy condition with one additional phalanx in pedal digit V, rather than the primitive condition (phalangeal formula: 2-3-3-3-3) of crown turtles. J. lingyuanensis is recovered with other coexisting turtles in the family Sinemydidae in the phylogenetic analysis. This discovery further confirms that hyperphalangy occurred multiple times in the early evolutionary history of the crown turtles. Hyperphalangy is possibly a homoplasy in Jeholochelys and the soft-shelled turtles to adapt to the aquatic environments.

13.
PeerJ ; 6: e4977, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29942679

RESUMO

A new three-dimensionally preserved troodontid specimen consisting of most of the skull, partial mandibles and six articulated cervical vertebrae (PMOL-AD00102) from the Early Cretaceous Yixian Formation of Beipiao, western Liaoning, China is identified as Sinovenator changii on the basis of a surangular with a "T"-shaped cross-section. High-resolution computed tomographic data for the skull of this new specimen facilitated a detailed description of the cranial anatomy of S. changii. New diagnostic features of S. changii include a well-developed medial shelf on the jugal, a slender bar in the parasphenoid recess, a lateral groove on the pterygoid flange of the ectopterygoid, and the lateral surface of the anterior cervical vertebrae bearing two pneumatic foramina. Our new observation confirms that the braincase of Sinovenator is not as primitive as previously suggested, although it still shows an intermediate state between derived troodontids and non-troodontid paravians in having an initial stage of the subotic recess and the otosphenoidal crest. Additionally, this new specimen reveals some novel and valuable anatomical information of troodontids regarding the quadrate-quadratojugal articulation, the stapes, the epipterygoid and the atlantal ribs.

14.
PLoS One ; 12(9): e0185486, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28950013

RESUMO

BACKGROUND: In the Early Cretaceous Jehol Biota, the toothless pterosaurs flourished with the chaoyangopterids and tapejarids playing a key role in understanding the early diversity and evolution of the Azhdarchoidea. Unlike the more diverse tapejarids, the rarer chaoyangopterids are characterized by a long and low rostrum, supporting a close relationship with the huge azhdarchids. Unfortunately, our knowledge is still limited in the osteology, paleoecology, and taxonomy of the Chaoyangopteridae. As one of the best preserved skeletons, the type and only specimen of Jidapterus edentus provides an opportunity to understand the morphology and paleoecology of the chaoyangopterids. RESULTS: Our study of the osteology of Jidapterus edentus reveals valuable information about the morphology of the Chaoyangopteridae such as a rostrum with a curved dorsal profile, high Rostral Index (RI), larger angle between the dorsal and postorbital processes of the jugal, sequentially shorter fourth to seventh cervical vertebrae, sternum with a plate wider than long, contact of the metacarpal I with the distal syncarpal, pneumatic foramen on first wing phalanx, hatchet-like postacetabular process with unconstricted neck and small dorsal process, distinctly concave anterior margin of pubis, subrectangular pubic plate with nearly parallel anterior and posterior margins, longer proximal phalanges of pedal digits III and IV, as well as reduced and less curved pedal unguals. These features further support the validity of Jidapterus edentus as a distinct species and the close relationship of the chaoyangopterids with the azhdarchids. Paleoecologically, the chaoyangopterids are probably like the azhdarchids, more terrestrial than the contemporaneous and putatively arboreal tapejarids, which may have been limited to the forest-dominated ecosystem of the Jehol Biota. DISCUSSION: The osteology of Jidapterus edentus further supports the close relationship of the Chaoyangopteridae with the Azhdarchidae in sharing a high RI value and reduced and mildly-curved pedal unguals, and it also implies a possible paleoecological similarity in their terrestrial capability. Combined with the putatively arboreal and herbivorous tapejarids, this distinct lifestyle of the chaoyangopterids provides new insights into the diversity of pterosaurs in the ecosystem of the Jehol Biota.


Assuntos
Dinossauros/classificação , Fósseis , Paleontologia , Animais , Dinossauros/anatomia & histologia
15.
PeerJ ; 5: e3274, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28462061

RESUMO

A small juvenile turtle is described from the Early Cretaceous Jehol Biota, shedding light on the juvenile morphology and ontogeny of Manchurochelys manchoukuoensis. Several juvenile features are uncovered, such as a small and circular carapace (less than half of the adult), wide vertebral scales, and lateral carapacial fontanelles. In contrast to the adult morphology, which has an oval carapace, closed lateral fontanelles, and longer vertebrals 2-4, the juvenile of M. manchoukuoensis is more comparable to that of Sinemys lens, except for earlier occurrence of the well-ossified carapace of the latter. Differs from Changmachelys bohlini, and Ordosemys liaoxiensis, in which the circular carapace is relatively independent of ontogenetic age, and the lateral fontanelles are only closed in adult stage of O. liaoxiensis. Therefore, the trajectory of ontogenetic change appears to be highly diversified in the sinemydids.

16.
R Soc Open Sci ; 4(2): 160672, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28386425

RESUMO

Pterosaurs were a unique clade of flying reptiles that were contemporaries of dinosaurs in Mesozoic ecosystems. The Pterodactyloidea as the most species-diverse group of pterosaurs dominated the sky during Cretaceous time, but earlier phases of their evolution remain poorly known. Here, we describe a 160 Ma filter-feeding pterosaur from western Liaoning, China, representing the geologically oldest record of the Ctenochasmatidae, a group of exclusive filter feeders characterized by an elongated snout and numerous fine teeth. The new pterosaur took the lead of a major ecological transition in pterosaur evolution from fish-catching to filter-feeding adaptation, prior to the Tithonian (145-152 Ma) diversification of the Ctenochasmatidae. Our research shows that the rise of ctenochasmatid pterosaurs was followed by the burst of eco-morphological divergence of other pterodactyloid clades, which involved a wide range of feeding adaptations that considerably altered the terrestrial ecosystems of the Cretaceous world.

17.
FEBS Lett ; 579(5): 1055-60, 2005 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-15710390

RESUMO

Transections of the entorhinal afferent fibers to hippocampus, perforant path (PP), result in the denervation in specific hippocampal subregions, which is followed by a series of plastic events including axon sprouting and reactive synaptogenesis. Many growth-associated molecules are thought to participate in these events. In the present study, we proved the upregulation of ephrin-A2 in the denervated areas of the ipsilateral hippocampus following PP transections. Interestingly, when the elevation of ephrin-A2 reached the maximum axon sprouting in the denervated areas almost finished, implying the possible inhibitory effect of ephrin-A2 on sprouting. In addition, ephrin-A2 expression was observed in synapses during reactive synaptogenesis, suggesting that this molecule might also be implicated in the formation and maturation of synapses in the denervated areas.


Assuntos
Efrina-A2/metabolismo , Hipocampo/metabolismo , Hipocampo/cirurgia , Via Perfurante/fisiologia , Regulação para Cima , Animais , Diferenciação Celular , Denervação , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Hipocampo/citologia , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos ICR , Sinapses/metabolismo
18.
Neuroreport ; 16(15): 1629-33, 2005 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-16189468

RESUMO

Thymosin beta4 is a major actin-sequestering molecule. Here, we report a prominent upregulation of thymosin beta4 in the hippocampus following entorhinal deafferentation. Northern blotting displayed a transient increase of thymosin beta4 mRNA in the deafferented hippocampus by 1.8, 2.3, 1.3 and 1.1-fold of controls, respectively, at 1, 3, 7 and 15 days post-lesion. In-situ hybridization confirmed that the induction of thymosin beta4 mRNA specifically occurred in the entorhinally denervated zones of the hippocampus. The double labeling of in-situ hybridization for thymosin beta4 mRNA with isolectin B4 cytochemistry showed that isolectin B4-positive microglial cells are responsible for deafferentation-induced thymosin beta4 mRNA expression. The results suggest that thymosin beta4 may participate in the process of microglial activation, which is the earliest event in lesion-induced plasticity.


Assuntos
Hipocampo/metabolismo , Microglia/metabolismo , RNA Mensageiro/biossíntese , Timosina/biossíntese , Animais , Northern Blotting , Denervação , Córtex Entorrinal/fisiologia , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Imuno-Histoquímica , Hibridização In Situ , Lectinas , Neurônios Aferentes/fisiologia , Ratos , Ratos Sprague-Dawley , Regulação para Cima
19.
Sci Rep ; 5: 16299, 2015 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-26553740

RESUMO

Morphological phylogenies stand in a major conflict with molecular hypotheses regarding the phylogeny of Cryptodira, the most diverse and widely distributed clade of extant turtles. However, molecular hypotheses are often considered a better estimate of phylogeny given that it is more consistent with the stratigraphic and geographic distribution of extinct taxa. That morphology fails to reproduce the molecular topology partly originates from problematic character polarization due to yet another contradiction around the composition of the cryptodiran stem lineage. Extinct sinemydids are one of these problematic clades: they have been either placed among stem-cryptodires, stem-chelonioid sea turtles, or even stem-turtles. A new sinemydid from the Early Cretaceous Jehol Biota (Yixian Formation, Barremian-Early Aptian) of China, Xiaochelys ningchengensis gen. et sp. nov., allows for a reassessment of the phylogenetic position of Sinemydidae. Our analysis indicates that sinemydids mostly share symplesiomorphies with sea turtles and their purported placement outside the crown-group of turtles is an artefact of previous datasets. The best current phylogenetic estimate is therefore that sinemydids are part of the stem lineage of Cryptodira together with an array of other Jurassic to Cretaceous taxa. Our study further emphasises the importance of using molecular scaffolds in global turtle analyses.


Assuntos
Tartarugas/anatomia & histologia , Algoritmos , Animais , Evolução Biológica , Biota , China , Fósseis/anatomia & histologia , Filogenia , Tartarugas/classificação
20.
J Neurol Sci ; 356(1-2): 148-52, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26143529

RESUMO

Although age is thought to correlate with the prognosis of glioma patients, the most appropriate age-group classification standard to evaluate prognosis had not been fully studied. This study aimed to investigate the influence of age-group classification standards on the prognosis of patients with high-grade hemispheric glioma (HGG). This retrospective study of 125 HGG patients used three different classification standards of age-groups (≤ 50 and >50 years old, ≤ 60 and >60 years old, ≤ 45 and 45-65 and ≥ 65 years old) to evaluate the impact of age on prognosis. The primary end-point was overall survival (OS). The Kaplan-Meier method was applied for univariate analysis and Cox proportional hazards model for multivariate analysis. Univariate analysis showed a significant correlation between OS and all three classification standards of age-groups as well as between OS and pathological grade, gender, location of glioma, and regular chemotherapy and radiotherapy treatment. Multivariate analysis showed that the only independent predictors of OS were classification standard of age-groups ≤ 50 and > 50 years old, pathological grade and regular chemotherapy. In summary, the most appropriate classification standard of age-groups as an independent prognostic factor was ≤ 50 and > 50 years old. Pathological grade and chemotherapy were also independent predictors of OS in post-operative HGG patients.


Assuntos
Envelhecimento , Neoplasias Encefálicas/classificação , Neoplasias Encefálicas/diagnóstico , Lateralidade Funcional , Glioma/classificação , Glioma/diagnóstico , Neoplasias Encefálicas/mortalidade , Feminino , Seguimentos , Glioma/mortalidade , Humanos , Estimativa de Kaplan-Meier , Masculino , Prognóstico , Modelos de Riscos Proporcionais
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