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1.
Nat Commun ; 15(1): 3081, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38594279

RESUMO

Tactile sensation and vision are often both utilized for the exploration of objects that are within reach though it is not known whether or how these two distinct sensory systems combine such information. Here in mice, we used a combination of stereo photogrammetry for 3D reconstruction of the whisker array, brain-wide anatomical tracing and functional connectivity analysis to explore the possibility of tacto-visual convergence in sensory space and within the circuitry of the primary visual cortex (VISp). Strikingly, we find that stimulation of the contralateral whisker array suppresses visually evoked activity in a tacto-visual sub-region of VISp whose visual space representation closely overlaps with the whisker search space. This suppression is mediated by local fast-spiking interneurons that receive a direct cortico-cortical input predominantly from layer 6 neurons located in the posterior primary somatosensory barrel cortex (SSp-bfd). These data demonstrate functional convergence within and between two primary sensory cortical areas for multisensory object detection and recognition.


Assuntos
Neurônios , Tato , Camundongos , Animais , Neurônios/fisiologia , Tato/fisiologia , Interneurônios , Reconhecimento Psicológico , Córtex Somatossensorial/fisiologia , Vibrissas/fisiologia
2.
Insects ; 13(11)2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36354836

RESUMO

Seven species in the genus Medetera (Diptera: Dolichopodidae) are described here: Medetera aglaops sp. nov., Medetera corsicana sp. nov., Medetera gibbosipyga sp. nov., Medetera hispanica sp. nov., Medetera lusitana sp. nov., Medetera parva sp. nov., and Medetera rectipyga sp. nov. They all originate from the wider Mediterranean region in southwestern Europe (Iberian Peninsula, southern France, Corsica, Sardinia). The most striking feature in most of the species is the bi- or multicolour pattern of the eyes, most conspicuous in Medetera aglaops sp. nov. and Medetera lusitana sp. nov. This character is shared by the male and female sex and is thus not regarded as Male Secondary Sexual Character. All species belong to the Medetera apicalis species group sensu Bickel and are closely related based on shared characters in the hypandrium and cercus. Interestingly, three species with and four species without the basal pair of anterodorsal and posterodorsal bristles on the mid tibia are represented. This suggests that this diagnostic character has less phylogenetic relevance than previously anticipated. Unlike most Palaearctic Medetera, at least five of the new species are mostly found on rocky substrates in dry biotopes with a sclerophyllous vegetation. This further supports their relationship with species of the Medetera muralis subclade sensu Pollet, Germann and Bernasconi.

3.
Adv Mater ; 33(52): e2105096, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34632625

RESUMO

The grain size is a determinant microstructural feature to enable the activation of deformation twinning in hexagonal close-packed (hcp) metals. Although deformation twinning is one of the most effective mechanisms for improving the strength-ductility trade-off of structural alloys, its activation is reduced with decreasing grain size. This work reports the discovery of the activation of deformation twinning in a fine-grained hcp microstructure by introducing ductile body-centered cubic (bcc) nano-layer interfaces. The fast solidification and cooling conditions of laser-based additive manufacturing are exploited to obtain a fine microstructure that, coupled with an intensified intrinsic heat treatment, permits to generate the bcc nano-layers. In situ high-energy synchrotron X-ray diffraction allows tracking the activation and evolution of mechanical twinning in real-time. The findings obtained show the potential of ductile nano-layering for the novel design of hcp damage tolerant materials with improved life spans.

4.
Materials (Basel) ; 14(14)2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34300775

RESUMO

Precipitation hardened and tempered martensitic-ferritic steels (TMFSs) are used in many areas of our daily lives as tools, components in power generation industries, or in the oil and gas (O&G) industry for creep and corrosion resistance. In addition to the metallurgical and forging processes, the unique properties of the materials in service are determined by the quality heat treatment (HT). By performing a quenching and partitioning HT during an in situ high energy synchrotron radiation experiment in a dilatometer, the evolution of retained austenite, martensite laths, dislocations, and carbides was characterized in detail. Atomic-scale studies on a specimen with the same HT subjected to a laser scanning confocal microscope show how dislocations facilitate cloud formation around carbides. These clouds have a discrete build-up, and thermodynamic calculations and density functional theory explain their stability.

5.
Materials (Basel) ; 14(4)2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33557276

RESUMO

Intermetallic γ-TiAl-based alloys are lightweight materials for high-temperature applications, e.g., in the aerospace and automotive industries. They can replace much heavier Ni-based alloys at operating temperatures up to 750 °C. Advanced variants of this alloy class enable processing routes that include hot forming. These alloys consist of three relevant crystallographic phases (γ-TiAl, α2-Ti3Al, ßo-TiAl) that transform into each other at different temperatures. For thermo-mechanical treatments as well as for adjusting alloy properties required under service conditions, the knowledge of the thermal expansion behavior of these phases is important. Therefore, thermal expansion coefficients were determined for the relevant phases in a Ti-Al-Nb-Mo alloy for temperatures up to 1100 °C using high-energy X-ray diffraction.

6.
Acta Orthop ; 92(1): 102-108, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33103536

RESUMO

Background and purpose - Classification of ankle fractures is crucial for guiding treatment but advanced classifications such as the AO Foundation/Orthopedic Trauma Association (AO/OTA) are often too complex for human observers to learn and use. We have therefore investigated whether an automated algorithm that uses deep learning can learn to classify radiographs according to the new AO/OTA 2018 standards.Method - We trained a neural network based on the ResNet architecture on 4,941 radiographic ankle examinations. All images were classified according to the AO/OTA 2018 classification. A senior orthopedic surgeon (MG) then re-evaluated all images with fractures. We evaluated the network against a test set of 400 patients reviewed by 2 expert observers (MG, AS) independently.Results - In the training dataset, about half of the examinations contained fractures. The majority of the fractures were malleolar, of which the type B injuries represented almost 60% of the cases. Average area under the area under the receiver operating characteristic curve (AUC) was 0.90 (95% CI 0.82-0.94) for correctly classifying AO/OTA class where the most common major fractures, the malleolar type B fractures, reached an AUC of 0.93 (CI 0.90-0.95). The poorest performing type was malleolar A fractures, which included avulsions of the fibular tip.Interpretation - We found that a neural network could attain the required performance to aid with a detailed ankle fracture classification. This approach could be scaled up to other body parts. As the type of fracture is an important part of orthopedic decision-making, this is an important step toward computer-assisted decision-making.


Assuntos
Fraturas do Tornozelo/classificação , Fraturas do Tornozelo/diagnóstico por imagem , Aprendizado Profundo , Algoritmos , Humanos , Radiografia , Suécia
7.
Zootaxa ; 4816(4): zootaxa.4816.4.5, 2020 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-33055686

RESUMO

Eucoryphus Mik is a Palaearctic genus of Dolichopodidae, previously with two described species confined to the montane and alpine zones of the European Alps. This paper describes a third species, Eucoryphus piscariviverus sp. nov., discovered in the mountains of southern Corsica. The systematic position of the genus Eucoryphus and the ecology of its species are discussed in detail and a key to males of the three species is provided.


Assuntos
Dípteros , Animais , França , Ilhas , Masculino
8.
Materials (Basel) ; 13(10)2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32455688

RESUMO

In situ dilatometry experiments using high energy synchrotron X-ray diffraction in transmission mode were carried out at the high energy material science beamline P07@PETRAIII at DESY (Deutsches Elektronen Synchrotron) for the tempering steel AISI 4140 at defined mechanical loading. The focus of this study was on the initial tempering state ( f e r r i t e ) and the hardened state ( m a r t e n s i t e ). Lattice strains were calculated from the 2D diffraction data for different h k l planes and from those temperature-dependent lattice plane specific diffraction elastic constants ( D E C s ) were determined. The resulting coupling terms allow for precise stress analysis for typical hypoeutectoid steels using diffraction data during heat treatment processes, that is, for in situ diffraction studies during thermal exposure. In addition, by averaging h k l specific Y o u n g ' s m o d u l i and P o i s s o n r a t i o s macroscopic temperature-dependent elastic constants were determined. In conclusion a novel approach for the determination of phase-specific temperature-dependent DECs was suggested using diffraction based dilatometry that provides more reliable data in comparison to conventional experimental procedures. Moreover, the averaging of lattice plane specific results from in situ diffraction analysis supply robust temperature-dependent macroscopic elastic constants for martensite and ferrite as input data for heat treatment process simulations.

9.
Int J Orthop Trauma Nurs ; 38: 100779, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32439319

RESUMO

INTRODUCTION: Hip fracture is common in the elderly and is associated with high comorbidity, mortality and complication rates. There has been an increase in the investigation of healthcare-related adverse events (AEs) in some patient groups but there is limited knowledge about hip fracture patients. The aim was to explore the incidence, preventability and nature of AEs in hip fracture patients. METHODS: One hundred and sixty three hip fracture patients participated. A record review was conducted of prospectively collected data using Global Trigger Tool methodology to identify AEs up to 90 days after surgery. RESULTS: Sixty two (38.0%) of 163 patients had at least one AE (range 1-7). One hundred and two AEs were identified and 62 (60.8%) were deemed preventable. Healthcare-associated infections e.g. pneumonia, urinary tract infections and pressure ulcers were common. AEs were more common in older patients and those with pre-existing health conditions. Fifty eight (56.9%) AEs caused temporary harm and 4 (3.9%) contributed to patient death. CONCLUSION: AEs are common in hip fracture patients and most are preventable. If the focus is on improving healthcare for these patients, we should be concentrating our efforts on reducing the number of these preventable AEs, with a particular emphasis on improving the care of older patients with pre-existing health conditions.


Assuntos
Fraturas do Quadril , Humanos , Incidência , Segurança do Paciente , Estudos Prospectivos
10.
Sci Technol Adv Mater ; 21(1): 205-218, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32341720

RESUMO

The aim of this work is to investigate quench induced precipitation during continuous cooling in aluminium wrought alloys EN AW-7150 and EN AW-6082 using in situ synchrotron wide-angle X-ray scattering (WAXS). While X-ray diffraction is usually an ex situ method, a variety of diffraction patterns were recorded during the cooling process, allowing in situ analysis of the precipitation process. The high beam energy of about 100 keV allows the beam to penetrate a bulk sample with a 4 mm diameter in a quenching dilatometer. Additionally, the high intensity of a synchrotron source enables sufficiently high time resolution for fast in situ cooling experiments. Reaction peaks could be detected and compared with results from differential scanning calorimetry (DSC) by this method. A methodology is presented in this paper to evaluate WAXS data in a way that is directly comparable to DSC-experiments. The results show a high correlation between both techniques, DSC and WAXS, and can significantly improve continuous cooling precipitation diagrams.

11.
Materials (Basel) ; 12(23)2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31795073

RESUMO

In situ synchrotron radiation diffraction was performed during the compression of as-cast Mg-3Nd-Zn alloys with different amounts (0, 0.5, 1, and 2 wt %) of Zn addition at room temperature. During the tests, the acoustic emission signals of the samples were recorded. The results show that the addition of Zn decreased the strength of the alloys but, at the same time, increased their ductility. In the earlier stages of deformation, twin formation and basal slip were the dominant deformation mechanisms. The twins tended to grow during the entire compression stage; however, the formation of new twins dominated only at the beginning of the plastic deformation. In order to accommodate the strain levels, the alloys containing Zn underwent nonbasal slip in the later stages of deformation. This can be attributed to the presence of precipitates containing Zn in the microstructure, inhibiting twin growth.

12.
Nanoscale ; 11(16): 7986-7995, 2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-30969286

RESUMO

Nature uses self-assembly of a fairly limited selection of components to build hard and tough protective tissues like nacre and enamel. The resulting hierarchical micro/nanostructures provide decisive toughening mechanisms while preserving strength. However, to mimic microstructural and mechanical characteristics of natural materials in application-relevant synthetic nanostructures has proven to be difficult. Here, we demonstrate a biomimetic synthesis strategy, based on chemical vapour deposition technology, employed to fabricate a protective high-temperature resistant nanostructured ceramic TiAlN thin film with six levels of hierarchy. By using just two variants of gaseous precursors and through bottom-up self-assembly, an irregularly arranged hard and tough multilayer stack was formed, consisting of hard sublayers with herringbone micrograins, separated by tough interlayers with spherical nanograins, respectively composed of lamellar nanostructures of alternating coherent/incoherent, hard/tough, single-/poly-crystalline platelets. Micro- and nanomechanical testing, performed in situ in scanning and transmission electron microscopes, manifests intrinsic toughening mechanisms mediated by five types of interfaces resulting in intergranular, transgranular and cleavage fracture modes with zigzag-like crack patterns at multiple length-scales. The hierarchical 2.7 µm thick film self-assembled during ∼15 minutes of deposition time shows hardness, fracture stress and toughness of ∼31 GPa, ∼7.9 GPa and ∼4.7 MPa m0.5, respectively, as well as phase/microstructural thermal stability up to ∼950/900 °C. The film's microstructural and mechanical characteristics represent a milestone in the production of protective and wear-resistant thin films.

13.
Materials (Basel) ; 12(4)2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30791527

RESUMO

In this study, new multilayer TiAl-based composites were developed and characterized. The materials were produced by spark plasma sintering (SPS) of elemental Ti and Al foils and ceramic particles (TiB2 and TiC) at 1250 °C. The matrix of the composites consisted of α2-TiAl and γ-TiAl lamellas and reinforcing ceramic layers. Formation of the α2 + γ structure, which occurred via a number of solid⁻liquid and solid⁻solid reactions and intermediate phases, was characterized by in situ synchrotron X-ray diffraction analysis. The combination of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis revealed that an interaction of TiC with Ti and Al led to the formation of a Ti2AlC Mn+1AXn (MAX) phase. No chemical reactions between TiB2 and the matrix elements were observed. The microhardness, compressive strength, and creep behavior of the composites were measured to estimate their mechanical properties. The orientation of the layers with respect to the direction of the load affected the compressive strength and creep behavior of TiC-reinforced composites. The compressive strength of samples loaded in the perpendicular direction to layers was higher; however, the creep resistance was better for composites loaded in the longitudinal direction. The microhardness of the composites correlated with the microhardness of reinforcing components.

14.
PLoS One ; 13(11): e0204391, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30427844

RESUMO

BACKGROUND: Patients with surgically treated osteoarthritis of the hip have an increased risk of cardiovascular morbidity and mortality many years after the operation compared with controls. Our hypothesis is that this increased risk after total hip arthroplasty (THA) is mediated by development of periprosthetic osteolysis leading to aseptic loosening of the implant. METHODS: We conducted a nation-wide, nested, case-control study consisting of patients receiving a cemented THA due to osteoarthritis between the years 1992 and 2005. Our study population included a total of 14,430 subjects identified in the Swedish hip arthroplasty register and linked to the Swedish National Patient Register. The case group consisted of patients (n = 2,886) who underwent reoperation of the treated hip due to osteolysis or aseptic loosening at any time within five years after the index surgery. Each case was matched with four controls (n = 11,544) who had not undergone reoperation. The main outcomes were cardiovascular events i.e. myocardial infarction, heart failure and cerebral infarction according to ICD-codes and time to the first cardiovascular event during the exposure period. Outcomes were subgrouped into cardiac and cerebral events. We used regression models to calculate the incidence rates and adjusted our results for confounders. FINDINGS: Overall, 5.1% of patients had cardiac events, with slightly more overall cardiovascular events occurring in the control group (8.1% vs. 6.7%, odds ratio 0.8, 95% confidence interval (CI) 0.7 to 1.0). After adjusting for confounders, the case group had an increased relative risk of 1.3 (95% confidence interval (CI) 1.1 to 1.3) for total number of cardiovascular events. Similar effect sizes were observed for time to first event. INTERPRETATION: Patients with osteoarthritis who received THA and subsequently underwent a revision operation due to loosening had a higher relative risk of developing cardiovascular events than controls. Thus there is an association which could be explained by a common inflammatory disease pathway that requires further experimental research.


Assuntos
Artroplastia de Quadril , Infarto Cerebral , Insuficiência Cardíaca , Prótese de Quadril/efeitos adversos , Infarto do Miocárdio , Osteólise , Sistema de Registros , Idoso , Infarto Cerebral/epidemiologia , Infarto Cerebral/etiologia , Feminino , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/etiologia , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Modelos Cardiovasculares , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/etiologia , Osteólise/epidemiologia , Osteólise/etiologia , Estudos Retrospectivos , Suécia/epidemiologia
15.
Zookeys ; (782): 49-79, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30275719

RESUMO

Recently, a species of Orthoceratium was collected in Greece that differs morphologically from the European species commonly presumed to be Orthoceratiumlacustre (Scopoli, 1763). Verification of the identity of the Greek species through comparison with 460 specimens of Orthoceratium from 17 West Palaearctic and one Afrotropical country, and examination of existing type material, revealed that the species recognized as O.lacustre in northwestern Europe for over 250 years is actually O.sabulosum (Becker, 1907), the other known species in the genus, which was originally described from Tunisia. Although the types of O.lacustre have been lost, a comparison of the distribution ranges of both species in Europe provided evidence that the species collected in Greece is conspecific with O.lacustre. Both species have distinct distributions in the West Palaearctic, with O.lacustre largely restricted to the northern border of the Mediterranean basin, and O.sabulosum more widespread, occurring in northwestern Europe, the western, southern, and eastern Mediterranean, the Middle East, and the Afrotropical Region (Tanzania). Both species are redescribed and fully illustrated, a neotype is designated for O.lacustre and a lectotype for O.sabulosum, and a key to males and females is provided. The misidentifications that lasted for over two centuries are explained by the omission by previous authors to study the type specimens, and inaccuracies in species descriptions and keys.

16.
Materials (Basel) ; 11(9)2018 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-30200647

RESUMO

Mg-4Nd base alloys with Zn additions of 3, 5 and 8 wt % were investigated with in situ synchrotron radiation diffraction during solidification. This method enabled the investigation of phase formation and transformation in the alloys. The diffraction results were supported with TEM observations on the as-solidified samples. The results show the effect of increased Zn addition on stabilizing the Mg3RE phase (RE-rare earth). The experimental results agree only partially with the theoretical calculations indicating the need to improve the existing thermodynamic database on the alloy system.

17.
Nat Commun ; 9(1): 3426, 2018 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-30143641

RESUMO

Metal-based additive manufacturing (AM) permits layer-by-layer fabrication of near net-shaped metallic components with complex geometries not achievable using the design constraints of traditional manufacturing. Production savings of titanium-based components by AM are estimated up to 50% owing to the current exorbitant loss of material during machining. Nowadays, most of the titanium alloys for AM are based on conventional compositions still tailored to conventional manufacturing not considering the directional thermal gradient that provokes epitaxial growth during AM. This results in severely textured microstructures associated with anisotropic structural properties usually remaining upon post-AM processing. The present investigations reveal a promising solidification and cooling path for α formation not yet exploited, in which α does not inherit the usual crystallographic orientation relationship with the parent ß phase. The associated decrease in anisotropy, accompanied by the formation of equiaxed microstructures represents a step forward toward a next generation of titanium alloys for AM.

18.
Materials (Basel) ; 11(7)2018 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-29958428

RESUMO

The mechanical properties of as-cast Mg-4Nd-xZn (x = 0, 3, 5 or 8 wt.%) alloys were investigated both in situ and ex situ in as-cast and solution-treated conditions. The additions of 3 or 5 wt.% Zn in the base Mg-4Nd alloy did not improve yield strength in comparison to the binary Mg-4Nd alloy. Mechanical properties were shown to improve only with the relatively high concentration of 8 wt.% Zn to Mg-4Nd. The change in intermetallic morphology from a continuous intermetallic to a lamella-like intermetallic was the primary reason for the decreased mechanical properties in Mg-4Nd-3Zn and Mg-4Nd-5Zn compared with Mg-4Nd and Mg-4Nd-8Zn. The dissolution of intermetallic at grain boundaries following heat treatment further indicated the importance of grain boundary reinforcement as shown in both in situ and ex situ compression testing. Azimuthal angle-time plots indicated little grain rotation most noticeably in Mg-4Nd, which also indicated the influence of a strong intermetallic network along the grain boundaries.

19.
BMJ Open ; 7(4): e013303, 2017 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-28389485

RESUMO

OBJECTIVES: To explore the value of simulation modelling in evaluating the effects of strategies to plan and schedule operating room (OR) resources aimed at reducing time to surgery for non-elective orthopaedic inpatients at a Swedish hospital. METHODS: We applied discrete-event simulation modelling. The model was populated with real world data from a university hospital with a strong focus on reducing waiting time to surgery for patients with hip fracture. The system modelled concerned two patient groups that share the same OR resources: hip-fracture and other non-elective orthopaedic patients in need of surgical treatment. We simulated three scenarios based on the literature and interaction with staff and managers: (1) baseline; (2) reduced turnover time between surgeries by 20 min and (3) one extra OR during the day, Monday to Friday. The outcome variables were waiting time to surgery and the percentage of patients who waited longer than 24 hours for surgery. RESULTS: The mean waiting time in hours was significantly reduced from 16.2 hours in scenario 1 (baseline) to 13.3 hours in scenario 2 and 13.6 hours in scenario 3 for hip-fracture surgery and from 26.0 hours in baseline to 18.9 hours in scenario 2 and 18.5 hours in scenario 3 for other non-elective patients. The percentage of patients who were treated within 24 hours significantly increased from 86.4% (baseline) to 96.1% (scenario 2) and 95.1% (scenario 3) for hip-fracture patients and from 60.2% (baseline) to 79.8% (scenario 2) and 79.8% (scenario 3) for patients with other non-elective patients. CONCLUSIONS: Healthcare managers who strive to improve the timelines of non-elective orthopaedic surgeries may benefit from using simulation modelling to analyse different strategies to support their decisions. In this specific case, the simulation results showed that the reduction of surgery turnover times could yield the same results as an extra OR.


Assuntos
Simulação por Computador , Fraturas do Quadril/cirurgia , Salas Cirúrgicas/organização & administração , Procedimentos Ortopédicos , Tempo para o Tratamento , Fluxo de Trabalho , Eficiência , Hospitais Universitários , Humanos , Suécia
20.
Neurol Res ; 37(2): 95-105, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24995467

RESUMO

OBJECTIVES: Methylated O6-methylguanin-DNA-methytransferase (MGMT) promoter methylation is associated with survival in patients with glioblastoma. Current evidence suggests that further mismatch repair genes play a pivotal role in the tumor response to treatment. Candidate genes are MLH1, MSH2, and MSH6. Formerly, we found evidence of prognostic impact of MLH1 and MSH6 immunohistochemical expression in a small series of patients with initial glioblastoma. METHODS: Two hundred and eleven patients were included who underwent macroscopically total removal of primary glioblastoma and at least one re-craniotomy for recurrence. Immunohistochemical staining was performed on paraffin-embedded specimens of initial tumors with specific antibodies against MLH1, MSH2, and MSH6. RESULTS were compared to the Ki67 proliferation index and patient survival. Additionally, fresh frozen samples from 16 paired initial and recurrent specimens were examined using real-time reverse transcription polymerase chain reaction (RT-PCR) with specific primers against MLH1, MSH2, and MSH6. RESULTS were compared to MGMT status and survival. RESULTS: (1) Immunohistochemical expression of MSH6 was significantly associated with the Ki67 proliferation index (P<0.001) but not with survival. (2) PCR revealed two patients with increasing expression of MLH1, MLH2, and MSH6 over treatment combined with lacking MGMT methylation. In another two patients, decreased MLH1, MSH2, and MSH6 expression was observed in combination with MGMT promoter methylation. DISCUSSION: Our data indicate that there may be glioblastoma patient subgroups characterized by MMR-expression changes beyond MGMT promoter methylation. The immunohistochemical expression of MLH1, MSH2, and MSH6 in initial glioblastoma is not associated with patient survival.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/biossíntese , Metilases de Modificação do DNA/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Proteínas de Ligação a DNA/biossíntese , Glioblastoma/metabolismo , Proteína 2 Homóloga a MutS/biossíntese , Recidiva Local de Neoplasia/metabolismo , Proteínas Nucleares/biossíntese , Proteínas Supressoras de Tumor/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Metilação de DNA , Reparo de Erro de Pareamento de DNA , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Feminino , Glioblastoma/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL , Recidiva Local de Neoplasia/mortalidade , Regiões Promotoras Genéticas , Análise de Sobrevida , Proteínas Supressoras de Tumor/genética , Adulto Jovem
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