RESUMO
This study aimed to investigate the T cell immunoreceptor with ITIM and Ig domains (TIGIT) expression in lung adenocarcinoma (LUAD). TIGIT expression was measured by western blot, reverse transcription quantitative polymerase chain reaction. Seventy-two paired surgical specimens were collected from patients with stage I-IV LUAD. The expression of TIGIT in surgical specimens was determined using immunohistochemistry. TIGIT was overexpressed in LUAD tissues. Moreover, overexpressed TIGIT was significantly associated with advanced clinical staging, lymph node metastasis, distant metastasis, and TP53 mutations in LUAD. Moreover, high expression of TIGIT was negatively correlated with purity of CD4+ T cells. High rations of TIGIT+CD4+ T cells predicted poor overall survival of LUAD patients. Additionally, high ratios of TIGIT+CD4+ T cells is closely related to CD4+ T cell depletion. Taken together, TIGIT was overexpressed in LUAD patients. High levels of TIGIT induced the alteration of CD4+ T cell based immunomodulation and predicted poor prognosis of LUAD patients. Therefore, TIGIT can be potential biomarker for LUAD.
Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Relevância Clínica , Expressão Ectópica do Gene , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/metabolismo , Adenocarcinoma de Pulmão/patologia , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Neoplasias Pulmonares/metabolismoRESUMO
5-Hydroxymethfurural (5-HMF) is naturally found in a variety of foods and beverages and represents a main inhibitor in the lignocellulosic hydrolysates used for fermentation. This study investigated the impact of 5-HMF on the genomic stability and phenotypic plasticity of the yeast Saccharomyces cerevisiae. Using next-generation sequencing technology, we examined the genomic alterations of diploid S. cerevisiae isolates that were subcultured on a medium containing 1.2 g/L 5-HMF. We found that in 5-HMF-treated cells, the rates of chromosome aneuploidy, large deletions/duplications, and loss of heterozygosity were elevated compared with that in untreated cells. 5-HMF exposure had a mild impact on the rate of point mutations but altered the mutation spectrum. Contrary to what was observed in untreated cells, more monosomy than trisomy occurred in 5-HMF-treated cells. The aneuploidy mutant with monosomic chromosome IX was more resistant to 5-HMF than the diploid parent strain because of the enhanced activity of alcohol dehydrogenase. Finally, we found that overexpression of ADH6 and ZWF1 effectively stabilized the yeast genome under 5-HMF stress. Our findings not only elucidated the global effect of 5-HMF on the genomic integrity of yeast but also provided novel insights into how chromosomal instability drives the environmental adaptability of eukaryotic cells.IMPORTANCESingle-cell microorganisms are exposed to a range of stressors in both natural and industrial settings. This study investigated the effects of 5-hydroxymethfurural (5-HMF), a major inhibitor found in baked foods and lignocellulosic hydrolysates, on the chromosomal instability of yeast. We examined the mechanisms leading to the distinct patterns of 5-HMF-induced genomic alterations and discovered that chromosomal loss, typically viewed as detrimental to cell growth under most conditions, can contribute to yeast tolerance to 5-HMF. Our results increased the understanding of how specific stressors stimulate genomic plasticity and environmental adaptation in yeast.
Assuntos
Instabilidade Genômica , Saccharomyces cerevisiae , Humanos , Saccharomyces cerevisiae/genética , Adaptação Fisiológica , Aneuploidia , Instabilidade CromossômicaRESUMO
Astragalus sinicus is a versatile legume crop, primarily utilized as a green manure in China. During 2020 and 2021, A. sinicus plants exhibiting dark brown or reddish-brown lesions or spots on leaves and stems were collected from fields in the Henan, Sichuan, and Guangxi provinces of China. Sixteen single-spore isolates were isolated from the infected leaf and stem tissue samples. Phylogenetic analyses based on the concatenated internal transcribed spacer, gapdh, and cmdA sequences indicated that 14 of them belong to Stemphylium astragali, whereas two isolates can be well separated from other known species in this genus. Based on the morphological characteristics and nucleotide polymorphisms with sister taxa, the two isolates were identified as a new species named S. henanense. Furthermore, pathogenicity assays showed that the S. astragali and S. henanense isolates caused leaf and stem spot symptoms on A. sinicus. Altogether, we describe a new species of Stemphylium (i.e., S. henanense sp. nov.) causing leaf spot disease of A. sinicus. In addition, this is the first report of S. astragali causing stem spot disease of A. sinicus.
Assuntos
Fabaceae , Doenças das Plantas , China , Filogenia , BioensaioRESUMO
Trifolium repens L. (White clover) a multipurpose legume crop, primarily utilized as a green manure in China. In March 2018, field investigations showed that a leaf spot disease occurred on T. repens in three fields with 50% to 80% incidence (50 plants in each field were investigated) in Nanchong City, Sichuan Province of China. Infected leaves showed symptoms of irregular dark brown spots in the center of leaves or at the leaf margins. Symptomatic leaves were surface sterilized with 3% NaClO for 3 min followed by 75% ethanol for 30 s and then rinsed in sterile water three times. Thereafter, tissue samples from margins of individual lesions were placed on potato dextrose agar and incubated at 25°C in the dark. Four pure cultures (Y3-1; Y3-2; Y3-3; Y3-4) were obtained by single spore isolation. On oatmeal agar medium, a colony reached 57 mm diameter after 9 d in alternating light and dark at 25â. Fimbriate aerial hypha were flat and compact with pale brown to dark brown color. Conidiogenous cells were hyaline, smooth, ampulliform to doliiform (n = 30), ranging from 4.1 to 10.5 µm long (6.6 ± 1.8 µm) × 2.2 to 5.7 µm wide (4.1 ± 0.8 µm). Conidia were ellipsoidal to cylindrical, hyaline, thin walled, smooth, aseptate, with 2 to 4 polar guttules (n = 50), ranging from 3.2 to 11.3 µm long (6.3 ± 1.1 µm) × 2.1 to 4.1 µm wide (2.8 ± 0.4 µm). Conidial matrix was whitish. Morphologically these isolates resembled species in Boeremia (Chen et al. 2015). Genomic DNA of each culture was extracted from mycelia using the quick and safe method (Chi et al. 2009). The 28S large subunit of nuclear ribosomal RNA (LSU) region, internal transcribed spacer (ITS) region, RNA polymerase II second largest subunit (RPB2), translation elongation factor 1-α (TEF 1-α), ß-Tubulin (TUB2) were amplified with corresponding primers (Carbone and Kohn 1999; Liu et al. 1999; Rehner and Samuels 1994; Sung et al. 2007; Vilgalys and Hester 1990; White et al. 1990; Woudenberg et al.2009). Sequences were deposited in GenBank with accession numbers: ON705759 to ON705766, ON734043 to ON734046 and ON841585 to ON841592. Phylogenetic analysis was conducted with combined sequences of the five loci using the maximum likelihood (ML) and the maximum parsimony (MP) methods. The four isolates and the extype strain of B. linicola (CBS 116.76) clustered together with high bootstrap support (BS) values (MLBS = 100; MPBS = 98). All sequences showed 100% identity to those of CBS 116.76, except the ITS region of our isolates (ON705759 to ON705762), which show 99.6% identity to that of CBS 116.76. Based on morphological characteristics and phylogenetic results, our isolates were identified as B. linicola, although the morphological characteristics of CBS 116.76 had not been characterized. To assess pathogenicity, a conidial suspension (approximately 105 CFU/mL) of isolate Y3-1 was sprayed on 1-month-old healthy plants in a greenhouse at 22â to 28â. Plants sprayed with sterilized water were used as negative controls. The test was conducted three times, each with 3 plants. After 10 days, the leaves of the plants showed irregular brown lesions that were similar to the symptoms observed in the field, control plants remained healthy. The pathogen was reisolated and confirmed to be B. linicola, thus completing the verification of Koch's Postulates. Compared to B. exigua, a causal pathogen associated with leaf spot on white clover reported by Wang et al (Wang et al. 2021), B. linicola produced larger conidia, and the two species did not cluster together in the phylogenetic tree. To our knowledge, this is the first report of leaf spot disease caused by B. linicola on Trifolium repens in China.
RESUMO
Palm grass (Setaria palmifolia) has been used as an ornamental plant and vegetable crop (Wu, 2009; Plarre, 1995). In June 2019, 2-10 mm severe leaf lesions with gray centers and brown-yellow edges were observed on the leaves of palm grass in Liuyang city (28°43'N, 114°12'E), Hunan province, China (Fig. 1A). Disease incidence on leaves was 20 - 40%. The infected leaves were collected and disinfected with 75% alcohol for 30 sec and 1% sodium hypochlorite for 1 min, followed by three rinses in sterilized ddH2O, dried on sterilized filter paper, and incubated on water agar for 48 h under continuous fluorescent light at 26â. Then, typical pyriform and 2-septate conidia (23.97 - 30.37 × 7.42 - 9.98 µm, N = 30) appeared at the lesions (Fig. 1B). Four single-spore were captured, and then grew on oatmeal tomato agar for seven days under continuous fluorescent light at 26â to obtain four isolates (LY-ZY-7a, -7b, -9b and -9c) and produce conidia for inoculation tests. The colony morphology of LY-ZY-7b on OTA was gray and floccose, and the growth rate was 6.15 - 6.31 mm/d at 26 °C (Fig. 1C). Spores of LY-ZY-7b were washed off with sterilized ddH2O plus 0.025% Tween-20 to make spore suspensions. For scratch inoculation, 10 µL spore suspension (1 × 105 spores/mL) was inoculated on the wound scratched with a sterilized pin along the vein (3 mm × 3 mm) on palm grass middle leaf of 4-week-old seedlings. The inoculated leaves were sealed in a 15-cm Petri dish. For spray inoculation, 20 mL spore suspension (5 × 104 spores/mL) was made and sprayed on ten healthy palm grasses of 4-week-old seedlings. Plants used as negative controls were sprayed with sterilized ddH2O plus 0.025% Tween-20 (Liu et al. 2022; Zhang et al. 2014). After inoculation, all plants were put into transparent boxes to maintain > 95% humidity and covered with black plastic bags for one day. Then, the boxes containing the plants were placed in a growth chamber at 26°C (12 h light / 12 h darkness photoperiod). After six days, typical blast-type lesions with brown-yellow edges were visible on the leaves. Control plants did not show symptoms (Fig. 1D, 1E). Microscopical examination showed that the conidia and conidiophore recovered from the lesion of the inoculated plants have the same morphology as those recovered from natural infected tissues (Fig. 1F, 1G). The colony morphology of the pathogen isolated from the artificially inoculated tissue was consistent with that of isolate LY-ZY-7b (Fig. 1C). The spore suspension (5 × 104 spores/mL) of isolate LY-ZY-7b and one rice-infecting strain P131 (Yang et al., 2010) was made and sprayed onto 4-week-old seedlings of three rice cultivars. But unfortunately, isolate LY-ZY-7b could not cause any disease lesions on the tested rice cultivars, whereas strain P131 produced many typical blast lesions on rice leaves (Fig. 1H). Then, the fungal genetic identity of four isolates (LY-ZY-7a, -7b, -9b, and -9c) was confirmed by comparison of the sequence obtained from partial DNA of Actin (ACT), ITS, and RPB1 loci from our isolates and those previously published by Klaubauf et al. 2014. The nucleotide sequences of ACT, ITS, and RPB1 were submitted to GenBank ON228695-ON228697 (ACT), ON210978-ON210980 (ITS), ON228698-ON228701 (RPB1). A phylogenetic tree deduced from a maximum likelihood analysis based on combined ACT-ITS-RPB1 sequence data of Pyricularia showed that these four isolates (LY-ZY-7a, -7b, -9b, and -9c) clustered together on Pyricularia oryzae, with a high bootstrap support value (Fig. 2). Based on morphological characteristics and molecular phylogeny, these four isolates were identified as P. oryzae (Klaubauf et al. 2014; Qi et al. 2019). To our knowledge, this is the first report of blast disease on palm grass caused by P. oryzae in China, which will help develop disease management strategies against palm grass blast. Moreover, as a host of P. oryzae, palm grass might contribute as an inoculum source for blast diseases on cereal crops (such as rice, wheat, and barley) caused by P. oryzae in the field.
RESUMO
Chronic fatigue syndrome (CFS) is characterized by extreme fatigue and disabling symptoms. Women with CFS often have a high risk of gynaecological problems such as irregular menstruation, endometriosis and pelvic pain and sexual dysfunction. Our previous results have shown that, in pregnant mice, CFS significantly decreased the progestational hormone level in serum, as well as learning and memory, and the function of the hypothalamus-pituitary-gonadal axis. In addition, the F1 generation also suffered from congenital hypothyroidism. At present, there has been no report about placenta formation and embryonic development in pregnant mice with CFS. The aim of the present study was to investigate the influence of CFS on the morphology, oxidative stress and Wnt/ß-catenin signalling pathway during placenta formation. In this study, we found that CFS decreased the number of implantation sites for blastocysts, and increased the number of absorbed, stillborn and malformed fetuses. The morphology and structure of the placenta were abnormal in pregnant mice with CFS. Further study found that the oxidative stress in serum, uterus and placenta was increased in pregnant mice with CFS, while the levels of antioxidase were decreased. CFS also inhibited the Wnt/ß-catenin signalling pathway in the placenta. These results suggested that inhibition of the Wnt/ß-catenin signalling pathway and enhanced oxidative stress play an important role in abnormal placentation in pregnant mice with CFS.
Assuntos
Síndrome de Fadiga Crônica , beta Catenina , Animais , Feminino , Camundongos , Estresse Oxidativo , Placenta , Gravidez , Via de Sinalização Wnt , beta Catenina/metabolismoRESUMO
When a stimulus is presented, its encoding is known to progress from low- to high-level features. How these features are decoded to produce perception is less clear, and most models assume that decoding follows the same low- to high-level hierarchy of encoding. There are also theories arguing for global precedence, reversed hierarchy, or bidirectional processing, but they are descriptive without quantitative comparison with human perception. Moreover, observers often inspect different parts of a scene sequentially to form overall perception, suggesting that perceptual decoding requires working memory, yet few models consider how working-memory properties may affect decoding hierarchy. We probed decoding hierarchy by comparing absolute judgments of single orientations and relative/ordinal judgments between two sequentially presented orientations. We found that lower-level, absolute judgments failed to account for higher-level, relative/ordinal judgments. However, when ordinal judgment was used to retrospectively decode memory representations of absolute orientations, striking aspects of absolute judgments, including the correlation and forward/backward aftereffects between two reported orientations in a trial, were explained. We propose that the brain prioritizes decoding of higher-level features because they are more behaviorally relevant, and more invariant and categorical, and thus easier to specify and maintain in noisy working memory, and that more reliable higher-level decoding constrains less reliable lower-level decoding.
Assuntos
Teorema de Bayes , Modelos Neurológicos , Percepção Visual/fisiologia , Humanos , Memória de Curto Prazo , Experimentação Humana não Terapêutica , Estimulação LuminosaRESUMO
QiShenYiQi Pills (QSYQ) is a compound Chinese medicine widely used in China for treatment of cardiovascular disease. However, limited data are available regarding the anti-fibrotic role of QSYQ after ischemia/reperfusion (I/R) injury. This study aimed to investigate the effect of post-treatment with QSYQ on myocardial fibrosis after I/R-induced myocardium injury, and the role of different compounds of QSYQ, focusing especially on the involvement of chemokine ribosomal protein S19 (RP S19) dimer and monocyte migration. Male Sprague-Dawley rats were subjected to left anterior descending coronary artery occlusion for 30 min followed by reperfusion with or without administration of QSYQ (0.6, 1.2, or 1.8 g/kg) once daily by gavage for 6 days. Post-treatment with QSYQ diminished I/R-induced infarct size, alleviated myocardium injury, attenuated myocardial fibrosis after 6 days of reperfusion, and restored heart function and myocardial blood flow after I/R. In addition, the drug significantly inhibited monocyte infiltration and macrophage polarization towards M2, which was attributable to chemokine RP S19 dimer. Moreover, Western blots revealed that QSYQ blocked I/R-induced increase in TGFß1 and TGFßRâ ¡ and reversed its relevant gene expression, such as Smad3,4,6,7, and inhibited the increase of MMP 2,9 expression. As the major components of QSYQ, astragaloside IV (AsIV), 3,4-dihydroxy-phenyl lactic acid (DLA), and notoginsenoside R1 (R1) were assessed as to the contribution of each of them to the expression of the proteins concerned. The results showed that the effect of AsIV was similar to QSYQ, while DLA and R1 only partly simulated the effect of QSYQ. The results provide evidence for the potential role of QSYQ in treating myocardial fibrosis following I/R injury. This effect may be associated with QSYQ's inhibition effect on monocyte chemotaxis and TGFß1/Smads signaling pathway with different component targeting distinct link (s) of the signaling.
Assuntos
Cardiotônicos/uso terapêutico , Medicamentos de Ervas Chinesas/uso terapêutico , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Animais , Cardiotônicos/farmacologia , Linhagem Celular , Medicamentos de Ervas Chinesas/farmacologia , Fibrose , Macrófagos/efeitos dos fármacos , Masculino , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/metabolismo , Miocárdio/patologia , RNA Interferente Pequeno/genética , Ratos Sprague-Dawley , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Smad/metabolismo , Fator de Crescimento Transformador beta1/metabolismoRESUMO
It has been debated whether kinematic features, such as the number of peaks or decomposed submovements in a velocity profile, indicate the number of discrete motor impulses or result from a continuous control process. The debate is particularly relevant for tasks involving target perturbation, which can alter movement kinematics. To simulate such tasks, finite-horizon models require two preset movement durations to compute two control policies before and after the perturbation. Another model employs infinite- and finite-horizon formulations to determine, respectively, movement durations and control policies, which are updated every time step. We adopted an infinite-horizon optimal feedback control model that, unlike previous approaches, does not preset movement durations or use multiple control policies. It contains both control-dependent and independent noises in system dynamics, state-dependent and independent noises in sensory feedbacks, and different delays and noise levels for visual and proprioceptive feedbacks. We analytically derived an optimal solution that can be applied continuously to move an effector toward a target regardless of whether, when, or where the target jumps. This single policy produces different numbers of peaks and "submovements" in velocity profiles for different conditions and trials. Movements that are slower or perturbed later appear to have more submovements. The model is also consistent with the observation that subjects can perform the perturbation task even without detecting the target jump or seeing their hands during reaching. Finally, because the model incorporates Weber's law via a state representation relative to the target, it explains why initial and terminal visual feedback are, respectively, less and more effective in improving end-point accuracy. Our work suggests that the number of peaks or submovements in a velocity profile does not necessarily reflect the number of motor impulses and that the difference between initial and terminal feedback does not necessarily imply a transition between open- and closed-loop strategies.
RESUMO
The aim of this study was to examine the effect of abscisic acid (ABA), sucrose, and auxin on grape fruit development and to assess the mechanism of these three factors on the grape fruit ripening process. Different concentrations of ABA, sucrose, and auxin were used to treat the grape fruit, and the ripening-related indices, such as physiological and molecular level parameters, were analyzed. The activity of BG protein activity was analyzed during the fruit development. Sucrose, ABA, and auxin influenced the grape fruit sugar accumulation in different ways, as well as the volatile compounds, anthocyanin content, and fruit firmness. ABA and sucrose induced, but auxin blocked, the ripening-related gene expression levels, such as softening genes PE, PG, PL, and CELL, anthocyanin genes DFR, CHI, F3H, GST, CHS, and UFGT, and aroma genes Ecar, QR, and EGS. ABA, sucrose, and glucose induced the fruit dry weight accumulation, and auxin mainly enhanced fruit dry weight through seed weight accumulation. In the early development of grape, starch was the main energy storage; in the later, it was glucose and fructose. Sucrose metabolism pathway-related gene expression levels were significant for glucose and fructose accumulation. BG protein activity was important in the regulation of grape ABA content levels. ABA plays a core role in the grape fruit development; sucrose functions in fruit development through two pathways: one was ABA dependent, the other ABA independent. Auxin blocked ABA accumulation to regulate the fruit development process.
Assuntos
Ácido Abscísico/metabolismo , Frutas/crescimento & desenvolvimento , Ácidos Indolacéticos/metabolismo , Sacarose/metabolismo , Vitis/metabolismo , Frutas/metabolismo , Desenvolvimento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Vitis/genética , Vitis/crescimento & desenvolvimentoRESUMO
Aim We aimed to identify clinical characteristics and risk factors associated with onset of high-altitude headache (HAH) after acute exposure at 3700 m. Method In two hours, 163 individuals ascended by plane to 3700 m. Demographic information, physiological and psychological measurements, cognitive function, physical work capacity tests and profile of mood states within one week prior to the departure and within 24 hours after arrival were examined. Results HAH patients featured significantly higher vertebral artery diastolic velocity (Vd), heart rate (HR) and pulmonary artery diameter. HAH was also associated with a more negative mood state, including scores for tension anxiety, depression, hostility, fatigue and confusion, as well as lower vigor (all p values <0.05). Furthermore, negative emotions were positively related to HAH severity. HAH slightly decreased cognitive functioning. HR, Vd, lack of vigor, confusion and self-reported anxiety (all p values <0.05) were independent risk factors for HAH. We have identified three independent baseline predictors for HAH including internal diameter of the left ventricle (LVD), Athens Insomnia Scale (AIS) and confusion score. Conclusions Higher HR, Vd, confusion and self-reported anxiety and insufficient vigor were independent risk factors for HAH. Furthermore, higher baseline LVD, AIS and confusion score are independent predictors of HAH.
Assuntos
Doença da Altitude/fisiopatologia , Doença da Altitude/psicologia , Cefaleia/etiologia , Hemodinâmica/fisiologia , Adolescente , Povo Asiático , Ventrículos do Coração/anatomia & histologia , Humanos , Masculino , Fatores de RiscoRESUMO
Modeling stereo transparency with physiologically plausible mechanisms is challenging because in such frameworks, large receptive fields mix up overlapping disparities, whereas small receptive fields can reliably compute only small disparities. It seems necessary to combine information across scales. A coarse-to-fine disparity energy model, with both position- and phase-shift receptive fields, has already been proposed. However, because each scale decodes only one disparity for each location and uses the decoded disparity to select cells at the next scale, this model cannot represent overlapping surfaces at different depths. We have extended the model to solve stereo transparency. First, we introduce multiplicative connections from cells at one scale to the next to implement coarse-to-fine computation. The connection is the strongest when the presynaptic cell's preferred disparity matches the postsynaptic cell's position-shift parameter, encouraging the next scale to encode residual disparities with the more reliable phase-shift mechanism. This modification not only eliminates the artificial decoding and selection steps of the original model but also enables maintenance of complete population responses throughout the coarse-to-fine process. Second, because of this modification, explicit decoding is no longer necessary but rather is for visualization only. We use a simple threshold criterion to decode multiple disparities from population energy responses instead of a single disparity in the original model. We demonstrate our model using simulations on a variety of transparent and nontransparent stereograms. The model also reproduces psychophysically observed disparity interactions (averaging, thickening, attraction, and repulsion) as the depth separation between two overlapping planes varies.
Assuntos
Algoritmos , Percepção de Forma/fisiologia , Modelos Neurológicos , Modelos Psicológicos , Neurônios/fisiologia , Disparidade Visual/fisiologia , Simulação por Computador/estatística & dados numéricos , Humanos , Visão Binocular/fisiologia , Campos Visuais/fisiologiaRESUMO
BACKGROUND: This study aimed to identify the systemic and cerebral hemodynamic characteristics and their roles in high-altitude headache (HAH) among young Chinese men following acute exposure. METHODS: The subjects (n = 385) were recruited in June and July of 2012. They completed case report form questionnaires, as well as heart rate (HR), blood pressure, echocardiogram and transcranial Doppler examinations at 3700 m following a two-hour plane flight. A subgroup of 129 participants was examined at two altitudes (500 and 3700 m). RESULTS: HAH was characterized by increased HR and cardiac output (CO) and lower saturation pulse oxygen (SpO(2)) (all p < 0.05). The change in tricuspid regurgitation was also different between the HAH positive (HAH+) and HAH negative (HAH-) subjects. Furthermore, the HAH+ subjects exhibited faster mean (V(m)), systolic (V(s)) and diastolic (V(d)) velocities in the basilar artery (BA; all p < 0.05) and a faster V(d) ( 25.96 ± 4.97 cm/s vs. 24.76 ± 4.76 cm/s, p = 0.045) in the left vertebral artery (VA). The bilateral VA asymmetry was also significantly different between the two groups. The pulsatility index (PI) and resistance index (RI) of left VA were lower in the HAH subjects (p < 0.05) and were negatively correlated with HAH (p < 0.05). Baseline CO and Vm in left VA (or right MCA in different regressions) were independent predictors for HAH, whereas CO/HR and ΔV(d) (V(d) difference between bilateral VAs) were independent risk factors for HAH at 3700 m. CONCLUSIONS: HAH was characterized, in part, by increased systemic hemodynamics and posterior cerebral circulation, which was reflected by the BA and left VA velocities, and lower arterial resistance and compliance. Furthermore, baseline CO and V(m) in left VA or right MCA at sea level were independent predictors for HAH, whilst bilateral VA asymmetry may contribute to the development of HAH at high altitude.
Assuntos
Doença da Altitude/fisiopatologia , Circulação Cerebrovascular/fisiologia , Cefaleia/fisiopatologia , Hemodinâmica/fisiologia , Adolescente , Adulto , Altitude , Doença da Altitude/complicações , Pressão Sanguínea/fisiologia , Cefaleia/etiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Inquéritos e Questionários , Adulto JovemRESUMO
PURPOSE: We aimed at identifying the cerebral hemodynamic characteristics of acute mountain sickness (AMS). METHODS: Transcranial Doppler (TCD) sonography examinations were performed between 18 and 24 h after arrival at 3,700 m via plane from 500 m (n = 454). A subgroup of 151 subjects received TCD examinations at both altitudes. RESULTS: The velocities of the middle cerebral artery, vertebral artery (VA) and basilar artery (BA) increased while the pulsatility indexes (PIs) and resistance indexes (RIs) decreased significantly (all p < 0.05). Velocities of BA were higher in AMS (AMS+) individuals when compared with non-AMS (AMS-) subjects (systolic velocity: 66 ± 12 vs. 69 ± 15 cm/s, diastolic velocity: 29 ± 7 vs. 31 ± 8 cm/s and mean velocity, 42 ± 9 vs. 44 ± 10 cm/s). AMS was characterized by higher diastolic velocity [V d_VA (26 ± 4 vs. 25 ± 4, p = 0.013)] with lower PI and RI (both p = 0.004) in VA. Furthermore, the asymmetry index (AI) of VAs was significantly lower in the AMS + group [-5.7 % (21.0 %) vs. -2.5 % (17.8 %), p = 0.016]. The AMS score was closely correlated with the hemodynamic parameters of BA and the V d_VA, PI, RI and AI of VA. CONCLUSION: AMS is associated with alterations in cerebral hemodynamics in the posterior circulation rather than the anterior one, and is characterized by higher blood velocity with lower resistance. In addition, the asymmetry of VAs may be involved in AMS.
Assuntos
Doença da Altitude/fisiopatologia , Circulação Cerebrovascular , Hemodinâmica , Adolescente , Adulto , Fatores Etários , Altitude , Estudos de Casos e Controles , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Even though retinal images of objects change their locations following each eye movement, we perceive a stable and continuous world. One possible mechanism by which the brain achieves such visual stability is to construct a craniotopic coordinate by integrating retinal and extraretinal information. There have been several proposals on how this may be done, including eye-position modulation (gain fields) of retinotopic receptive fields (RFs) and craniotopic RFs. In the present study, we investigated coordinate systems used by RFs in the lateral intraparietal (LIP) cortex and frontal eye fields (FEF) and compared the two areas. We mapped the two-dimensional RFs of neurons in detail under two eye fixations and analyzed how the RF of a given neuron changes with eye position to determine its coordinate representation. The same recording and analysis procedures were applied to the two brain areas. We found that, in both areas, RFs were distributed from retinotopic to craniotopic representations. There was no significant difference between the distributions in the LIP and FEF. Only a small fraction of neurons was fully craniotopic, whereas most neurons were between the retinotopic and craniotopic representations. The distributions were strongly biased toward the retinotopic side but with significant craniotopic shifts. These results suggest that there is only weak evidence for craniotopic RFs in the LIP and FEF, and that transformation from retinotopic to craniotopic coordinates in these areas must rely on other factors such as gain fields.
Assuntos
Macaca , Campos Visuais , Animais , Lobo Frontal/fisiologia , Movimentos Oculares , EncéfaloRESUMO
The nature and function of perisaccadic receptive field (RF) remapping have been controversial. We use a delayed saccade task to reduce previous confounds and examine the remapping time course in the lateral intraparietal area and frontal eye fields. In the delay period, the RF shift direction turns from the initial fixation to the saccade target. In the perisaccadic period, RFs first shift toward the target (convergent remapping), but around the time of saccade onset/offset, the shifts become predominantly toward the post-saccadic RF locations (forward remapping). Thus, unlike forward remapping that depends on the corollary discharge (CD) of the saccade command, convergent remapping appears to follow attention from the initial fixation to the target. We model the data with attention-modulated and CD-gated connections and show that both sets of connections emerge automatically in neural networks trained to update stimulus retinal locations across saccades. Our work thus unifies previous findings into a mechanism for transsaccadic visual stability.
Assuntos
Neurônios , Movimentos Sacádicos , Lobo Parietal , Lobo Frontal , Estimulação LuminosaRESUMO
Optimization models explain many aspects of biological goal-directed movements. However, most such models use a finite-horizon formulation, which requires a prefixed movement duration to define a cost function and solve the optimization problem. To predict movement duration, these models have to be run multiple times with different prefixed durations until an appropriate duration is found by trial and error. The constrained minimum time model directly predicts movement duration; however, it does not consider sensory feedback and is thus applicable only to open-loop movements. To address these problems, we analyzed and simulated an infinite-horizon optimal feedback control model, with linear plants, that contains both control-dependent and control-independent noise and optimizes steady-state accuracy and energetic costs per unit time. The model applies the steady-state estimator and controller continuously to guide an effector to, and keep it at, target position. As such, it integrates movement control and posture maintenance without artificially dividing them with a precise, prefixed time boundary. Movement pace is determined by the model parameters, and the duration is an emergent property with trial-to-trial variability. By considering the mean duration, we derived both the log and power forms of Fitts's law as different approximations of the model. Moreover, the model reproduces typically observed velocity profiles and occasional transient overshoots. For unbiased sensory feedback, the effector reaches the target without bias, in contrast to finite-horizon models that systematically undershoot target when energetic cost is considered. Finally, the model does not involve backward and forward sweeps in time, its stability is easily checked, and the same solution applies to movements of different initial conditions and distances. We argue that biological systems could use steady-state solutions as default control mechanisms and might seek additional optimization of transient costs when justified or demanded by task or context.
Assuntos
Algoritmos , Modelos Neurológicos , Modelos Teóricos , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Animais , HumanosRESUMO
High-altitude pulmonary edema (HAPE) is a non-cardiogenic type of pulmonary edema developing altitudes > 2,500 m. Angiotensin converting enzyme (ACE) and nitric oxide synthase 3 (NOS3) play important roles in regulating pulmonary vascular tone. To assess associations between genetic variants in the ACE and NOS3 genes and HAPE risk, 27 HAPE patients and 108 matched controls were genotyped and analyzed. The indicated HAPE association of the NOS3 G894T (Glu298Asp) single nucleotide polymorphism (SNP), which may change NO production, was further evaluated by a meta-analysis of six studies involving 399 HAPE patients and 495 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined with fixed-effects models. Stratification analyses of ethnicity and geographic location were performed. Significant associations were observed for the dominant model in two ACE tag SNPs influencing serum ACE concentrations (rs8066114 polymorphism: GG+CG vs. CC; rs4461142 polymorphism: TT+CT vs. CC). Furthermore, Single-locus analysis indicated significantly different distributions of G allele frequency between the cases (29.63%) and controls (17.13%) for the ACE rs8066114 polymorphism. The case-control distributions of genotype frequencies and T allele frequency of NOS3 G894T (Glu298Asp) polymorphism were significantly higher in the cases than controls, and the NOS3 G894T (Glu298Asp) SNP showed elevated HAPE risk under the dominant model (TT+GT vs. GG). Meta-analysis showed overall association of NOS3 G894T SNP with HAPE risk under the allele contrast and dominant genetic models, which remained significant for Asians. In conclusion, ACE rs8066114 and rs4461142 and NOS3 rs1799983 (G894T) polymorphisms may be associated with increased HAPE risk in Asians.
Assuntos
Doença da Altitude/genética , Hipertensão Pulmonar/genética , Óxido Nítrico Sintase Tipo III/genética , Peptidil Dipeptidase A/genética , Polimorfismo de Nucleotídeo Único/genética , Doença da Altitude/etnologia , Povo Asiático/genética , Estudos de Casos e Controles , China , Primers do DNA/genética , Estudos de Associação Genética , Genótipo , Humanos , Hipertensão Pulmonar/etnologia , Modelos Genéticos , Razão de Chances , Reação em Cadeia da Polimerase , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
The nature and function of perisaccadic receptive-field (RF) remapping have been controversial. We used a delayed saccade task to reduce previous confounds and examined the remapping time course in areas LIP and FEF. In the delay period, the RF shift direction turned from the initial fixation to the saccade target. In the perisaccadic period, RFs first shifted toward the target (convergent remapping) but around the time of saccade onset/offset, the shifts became predominantly toward the post-saccadic RF locations (forward remapping). Thus, unlike forward remapping that depends on the corollary discharge (CD) of the saccade command, convergent remapping appeared to follow attention from the initial fixation to the target. We modelled the data with attention-modulated and CD-gated connections, and showed that both sets of connections emerged automatically in neural networks trained to update stimulus retinal locations across saccades. Our work thus unifies previous findings into a mechanism for transsaccadic visual stability.
RESUMO
Enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to analyze the difference of intestinal microbial community diversity between healthy and orally infected rabbits with Entamoeba histolytica. The dynamic changes in different parts of digestive system including the duodenum, jejunum, ileum, caecum, and rectum in healthy and infected rabbits at different time points were also tested. The intestinal microbial community of the control healthy rabbits was steady, and the total number of ERIC-PCR bands in the control healthy rabbit was the least in the rectum and the most in the caecum. ERIC-PCR bands of orally inoculated rabbits did not obviously change until 24 h after postinoculation (p.i.). The numbers of the ERIC-PCR bands gradually decreased from 24 to 72 h p.i., and then, with the development of disease, the band numbers gradually increased until 6 days p.i. Sequence analysis showed that the nucleotide sequence homologies of the fragment about 1,200 bp of infected ileum sampled at 32 h p.i. were above 95 % with Sinorhizobium meliloti enterobacterial, Erwinia amylovora and Salmonella typhimurium, and the nucleotide sequence homologies of the fragment about 300 bp of infected ileum sampled at 48 h p.i. were more than 90 % with Xanthomonas campestris enterobacterial, Yersinia enterocolitica subsp., Shigella flexneri, S. meliloti enterobacterial, Yersinia pestis, Klebsiella pneumoniae subsp., and Escherichia coli. The prominent bacteria had changed after E. histolytica infection. The DNAstar of staple of ERIC-PCR showed that aerobe and facultative aerobe (E. coli, Shigella, and Salmonella) became preponderant bacilli in the intestine of orally infected rabbits with E. histolytica.