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排序方式: 共有5789条查询结果,搜索用时 15 毫秒
81.
Camila P. Almeida Camila O. Silveira Enio F. Ferreira Marcia C. Ferreira Gabriella G. Oliveira Emerson S. Veloso Felipe H.S. Silva Santuza S. Coelho Leonardo M. Moraes Fernando M. Reis Helen L. Del Puerto 《Acta histochemica》2021,123(2):151670
Apoptosis regulation in luteinized granulosa cells (LGC) during assisted reproduction procedures is still controversial. Caspase-3 is a major apoptosis mediator encoded by CASP3 and formed through cleavage of its precursor pro-caspase-3. The aim of this study was to investigate the expression patterns of pro-caspase-3 (mRNA and protein) and cleaved caspase-3 in human LGC. Thirty-five women undergoing controlled ovarian stimulation for in vitro fertilization were prospectively enrolled in the study. LGC were isolated from follicular fluid during oocyte pickup and evaluated by immunocytochemistry for pro-caspase-3 and cleaved caspase-3, and by real-time PCR for CASP3 mRNA expression. We found a positive staining of pro-caspase-3 in 77 % of the LGC (95 % confidence interval [CI] 60%–84%), whereas cleaved caspase-3 was found in only 4% of the cells (95 % CI 3%–6%). The abundance of cells expressing pro-caspase-3 was independent from CASP3 mRNA levels (r = 0.24, p = 0.255) and did not correlate with the amount of cleaved caspase-3 (r = -0.24, p = 0.186). Multivariable logistic regression showed that pro-caspase-3 positivity was not influenced by clinical characteristics such as age, cause or length of infertility, antral follicle count or hormonal drugs used to induce ovulation. These findings suggest that pro-caspase-3 is constitutively expressed in LGC, allowing quick cleavage into active caspase-3 and apoptosis triggering whenever needed in the course of gonadotropin-induced follicular development. 相似文献
82.
Brenda Stefany dos Santos Braga Dário Lisboa Fernandes-Neto Leonardo Conceição Teixeira Juliane da Silva Costa Maria Auxiliadora Pantoja Ferreira Verônica Regina Oliveira-Bahia José Ribamar Felipe Marques Diva Anelie de Araújo Guimarães 《Anatomical record (Hoboken, N.J. : 2007)》2021,304(6):1280-1293
The morphological study of limbs is important for the understanding of tetrapod biology, where it can be applied to taxonomy and phylogeny, as well ecology and behavior. In this study area, osteogenesis is a subject in Kinosternidae, which has been little researched. The main aim of this study was to characterize the skeletogenesis of Kinosternon scorpioides limbs. Samples were histologically processed, and the embryos were cleared with potassium hydroxide and stained with alcian blue and alizarin red. It was observed that the limbs arose in embryonic Stage 10 as mesenchymal condensate cells. The first stylopodium chondrification centers were noted at Stage 14. Zeugopodium chondrification centers appeared at Stage 15; carpal, metacarpal, tarsal, and metatarsal regions were observed at Stage 16, and the cartilage molds of all bones limbs were present at Stage 18. Ossification began in the humerus and femur at Stage 20, and continued into the radius, ulna, tibia, and fibula bones. By Stage 23, it was already effectively directed toward the bone epiphyses in both limbs. At Stage 26 and hatching, only articular cartilages remained, and in the majority of samples the carpal region showed no affinity for alcian blue or alizarin red staining. This study acts as an indicative parameter of the taxon's normal development and can contribute to the phylogenetic understanding of this group. 相似文献
83.
D.J. Petite Felipe M.I. Rivera Campos J. San Miguel Espinosa Y. Malo Rubio J.C. Flores Quan M.V. Cuartero Revilla 《Radiologia》2021,63(4):324-333
Background and aimsWe aimed to analyze the relationship between the initial chest X-ray findings in patients with severe acute respiratory syndrome due to infection with SARS-CoV-2 and eventual clinical worsening and to compare three systems of quantifying these findings.Material and methodsThis retrospective study reviewed the clinical and radiological evolution of 265 adult patients with COVID-19 attended at our center between March 2020 and April 2020. We recorded data related to patients’ comorbidities, hospital stay, and clinical worsening (admission to the ICU, intubation, and death). We used three scoring systems taking into consideration 6 or 8 lung fields (designated 6 A, 6 B, and 8) to quantify lung involvement in each patient's initial abnormal chest X-ray and to classify its severity as mild, moderate, or severe, and we compared these three systems. We also recorded the presence of alveolar opacities and linear opacities (fundamentally linear atelectasis) in the first chest X-ray with pathologic findings.ResultsIn the χ2 analysis, moderate or severe involvement in the three classification systems correlated with hospital admission (p = 0.009 in 6 A, p = 0.001 in 6 B, and p = 0.001 in 8) and with death (p = 0.02 in 6 A, p = 0.01 in 6 B, and p = 0.006 in 8). In the regression analysis, the most significant associations were 6 B with alveolar involvement (OR 2.3; 95%CI 1.1.–4.7; p = 0.025;) and 8 with alveolar involvement (OR 2.07; 95% CI 1.01.–4.25; p = 0.046). No differences were observed in the ability of the three systems to predict clinical worsening by classifications of involvement in chest X-rays as moderate or severe.ConclusionModerate/severe extension in the three chest X-ray scoring systems evaluating the extent of involvement over 6 or 8 lung fields and the finding of alveolar opacities in the first abnormal X-ray correlated with mortality and the rate of hospitalization in the patients studied. No significant difference was found in the predictive ability of the three classification systems proposed. 相似文献
84.
ObjectivesTo compare the primary stability of miniscrews after repeated cycles of insertion through insertion torque (IT) measurements and resonance frequency analysis (RFA).Materials and MethodsSixty titanium miniscrews were divided into two groups according to the insertion protocol: one with predrilled sites and the other self-drilled into porcine iliac crest bone specimens. Each group had three cycles of reinsertion. After each insertion, the IT and RFA were measured. The IT was measured by using a torque meter, and the RFA was measured using the Osstell ISQ device. A total of five miniscrews of each group were selected for sequential assessment of the morphology of their tip and threads using scanning electron microscopy after each insertion cycle.ResultsNo statistically significant differences were found in the IT values of miniscrews reinserted up to three times in the group with predrilled surgical sites. The IT value increased significantly with the number of reinsertions in the self-drilled group. The RFA value decreased as the number of insertions increased in both groups.ConclusionsUnder the conditions of this in vitro study, reinserting miniscrews deteriorates the integrity of their tip and thread. Reinsertion should be discouraged particularly when insertion sites are not predrilled. 相似文献
85.
Gabriel Felipe de Bragança Júlia Dantas Mazão Antheunis Versluis Carlos José Soares 《The Journal of prosthetic dentistry》2021,125(5):778-787
Statement of problemHow the polymerization shrinkage, loading, and mechanical properties of luting materials affect the shrinkage and functional stresses in ceramic laminate veneers (CLVs) with and without tooth preparation is unclear.PurposeThe purpose of this finite element analysis (FEA) study was to evaluate the effect of the polymerization shrinkage, functional loading, and mechanical properties of different luting materials on the stresses in ultrathin 0.3-mm CLVs with and without tooth preparation.Material and methodsThree resin cements, RelyX Veneer (RV), Allcem Veneer APS (AV), Variolink Esthetic LC (VE), and 1 flowable composite resin, Tetric N-Flow (TF), were tested for post-gel shrinkage (Shr), Knoop hardness (KHN), elastic modulus (E), compressive strength (CS), and diametral tensile strength (DTS). IPS e.max CAD disks of 0.3-mm thickness were made for simulating the effects of light attenuation. Eight 2-dimensional finite element models (Marc-Mentat) of a maxillary central incisor were generated to evaluate the polymerization shrinkage stress of different materials for luting 0.3-mm CLVs with or without tooth preparation and the stress during functional loading by using a modified von Mises criterion (mvm). Collected data from Shr, KHN, and E were submitted to 2-way ANOVA and the Tukey HSD test (α=.05).ResultsLight attenuation by the 0.3-mm ceramic disk did not significantly affect the E values, but Shr was significantly lower in VE (26%) and TF (35%). TF had lower volumetric Shr (%) when interposing a ceramic disk (0.31%). Both tested tooth preparation options showed similar stress distributions from polymerization shrinkage or functional loading, with higher stress concentration on the incisal edge and also on the cervical surface. The model featuring tooth preparation and RV resin cement had the highest and VE the lowest stress levels.ConclusionsThe flowable composite resin had similar mechanical properties as the resin cements. The stress distribution from shrinkage and functional loading was similar for both techniques with or without tooth preparation. 相似文献
86.
87.
Juan Venegas Felipe Díaz Tamara Rojas Sandra Miranda M. I. Jercic Christian González William Coñoepán Alex Vargas Sergio Pichuantes Marta Gajardo Jorge Rodríguez Gittith Sánchez 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2013,58(2):139-148
The objective of this study was to investigate if there is specific host-parasite association in Chilean populations of Trypanosoma cruzi. For this purpose, two groups of parasites were analyzed, one from chronic chagasic patients, and the other from Triatoma infestans triatomines in three regions of the country. The first group consisted of four types of samples: parasites from peripheral blood of non-cardiopathic T. cruzi infected patients (NB); parasites from their corresponding xenodiagnosis (NX); parasites from peripheral blood of T. cruzi infected cardiopathic patients (CB) and parasites from their xenodiagnostics (CX). The T. infestans sample in turn was from three regions: III, V and M (Metropolitan). The genetic differentiation by the Fisher exact method, the lineage distribution of the samples, the molecular phylogeny and the frequency of multiclonality were analysed. The results show that not only are the groups of T. cruzi clones from Chagas disease patients and vectors genetically differentiated, but also all the sub-groups (NB, NX, CB and CX) from the III, V and M regions. The analysis of lineage distribution was concordant with the above results, because significant differences among the percentages of TcI, TcIII and hybrids (TcV or TcVI) were observed. The phylogenetic reconstruction with these Chilean T. cruzi samples was coherent with the above results because the four chagasic samples clustered together in a node with high bootstrap support, whereas the three triatomine samples (III, V and M) were located apart from that node. The topology of the tree including published T. cruzi clones and isolates was concordant with the known topology, which confirmed that the results presented here are correct and are not biased by experimental error. Taken together the results presented here are concordant with a specific host-parasite association between some Chilean T. cruzi populations. 相似文献
88.
89.
90.
Felipe Lipsky Luis Henrique da Silveira Lacerda Srgio Ricardo de Lazaro Elson Longo Juan Andrs Miguel Angel San-Miguel 《RSC advances》2020,10(51):30640
Over the years, the possibility of using solar radiation in photocatalysis or photodegradation processes has attracted remarkable interest from scientists around the world. In such processes, due to its electronic properties, Ag3PO4 is one of the most important semiconductors. This work delves into the photocatalytic activity, stability, and reactivity of Ag3PO4 surfaces by comparing plane waves with projector augmented wave and localized Gaussian basis set simulations, at the atomic level. The results indicate that the (110) surface, in agreement with previous experimental reports, displays the most suitable characteristics for photocatalytic activity due to its high reactivity, i.e. the presence of a large amount of undercoordinated Ag cations and a high value work function. Beyond the innovative results, this work shows a good synergy between both kinds of DFT approaches.Over the years, the possibility of using solar radiation in photocatalysis or photodegradation processes has attracted remarkable interest from scientists around the world. 相似文献