Parenchyma

薄壁组织
  • 文章类型: Journal Article
    我们研究了三种动态葡萄糖增强(DGE)MRI方法,用于在临床场强(3T)下敏感地监测脑实质和脑脊液(CSF)中的葡萄糖摄取和清除率。通过比较三个序列,即,卡尔-珀塞尔-迈博姆-吉尔(CPMG),谐振可变延迟多脉冲(onVDMP),和共振自旋锁(onSL),提出了一种具有截断多线性奇异值分解(MLSVD)去噪的高灵敏度DGEMRI方案。在三种方法中,CPMG方法检测实质DGE信号的灵敏度最高,而onVDMP和onSL对于CSFDGE成像更稳健。这里,onVDMP用于CSF成像,因为它在本研究中表现出DGE结果的最佳稳定性。引入截短的MLSVD去噪方法以进一步提高灵敏度。在具有50%/25%/12.5%w/w的D-葡萄糖注射的小鼠脑中检查所提出的DGEMRI方案。结果表明,这种组合可以检测到来自脑实质和CSF的DGE信号变化,低至12.5%w/w的D-葡萄糖注射。拟议的DGEMRI方案可以敏感地检测到在临床相关浓度下注射D-葡萄糖后来自脑实质和CSF的葡萄糖信号变化。显示出很高的临床翻译潜力。
    We investigated three dynamic glucose-enhanced (DGE) MRI methods for sensitively monitoring glucose uptake and clearance in both brain parenchyma and cerebrospinal fluid (CSF) at clinical field strength (3 T). By comparing three sequences, namely, Carr-Purcell-Meiboom-Gill (CPMG), on-resonance variable delay multipulse (onVDMP), and on-resonance spin-lock (onSL), a high-sensitivity DGE MRI scheme with truncated multilinear singular value decomposition (MLSVD) denoising was proposed. The CPMG method showed the highest sensitivity in detecting the parenchymal DGE signal among the three methods, while both onVDMP and onSL were more robust for CSF DGE imaging. Here, onVDMP was applied for CSF imaging, as it displayed the best stability of the DGE results in this study. The truncated MLSVD denoising method was incorporated to further improve the sensitivity. The proposed DGE MRI scheme was examined in mouse brain with 50%/25%/12.5% w/w D-glucose injections. The results showed that this combination could detect DGE signal changes from the brain parenchyma and CSF with as low as a 12.5% w/w D-glucose injection. The proposed DGE MRI schemes could sensitively detect the glucose signal change from brain parenchyma and CSF after D-glucose injection at a clinically relevant concentration, demonstrating high potential for clinical translation.
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  • 文章类型: Journal Article
    Xylem traits are critical plant functional traits associated with water transport, mechanical support, and carbohydrate and water storage. Studies on the xylem hydraulic efficiency-safety tradeoff are numerous; however, the storage function of xylem parenchyma is rarely considered. The effects of a substantial number of xylem traits on water transport, embolism resistance, mechanical support, storage capacity and nonstructural carbohydrate (NSC) content were investigated in 19 temperate broadleaf species planted in an arid limestone habitat in northern China. There was no xylem hydraulic efficiency-safety tradeoff in the 19 broadleaf species. The total parenchyma fraction was negatively correlated with the fiber fraction. Embolism resistance was positively correlated with indicators of xylem mechanical strength such as vessel wall reinforcement, vessel wall thickness and fiber wall thickness, and was negatively related to the axial parenchyma fraction, especially the paratracheal parenchyma fraction. The paratracheal parenchyma fraction was positively correlated with the ratio of the paratracheal parenchyma fraction to the vessel fraction. In addition, the xylem NSC concentration was positively related to the total parenchyma fraction and axial parenchyma fraction. There was a storage capacity-embolism resistance tradeoff in the xylem of 19 broadleaf species in arid limestone habitats. We speculate that the temperate broadleaf species may show a spectrum of xylem hydraulic strategies, from the embolism resistance strategy related to a more negative P50 (the water potential corresponding to 50% loss of xylem conductivity) to the embolization repair strategy based on more paratracheal parenchyma.
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  • 文章类型: Journal Article
    研究植物次生木质部沿纬度梯度的空间分配模式有助于评估木本被子植物木质部的结构功能权衡。编制了包括中国700种木质被子植物在内的解剖数据集,以及每个物种的纬度和气候数据。血管的相对组织分数,纤维,分析了木质部的薄壁组织(包括射线和轴向薄壁组织),以确定纬度差异和系统发育对解剖变异的影响。分析揭示了跨纬度的船舶和非船舶之间的权衡,组织分数的权衡主要发生在血管和纤维之间,在纤维和总薄壁组织之间。在13个气候变量中,在所有细胞类型的双变量模型中,热指数通常比水分指数具有更大的解释力,虽然意味着年气温,最冷月份的平均温度,和年度实际蒸散量包含在解释不同组织分数方差的顶级多变量模型中。系统发育和气候共同解释了木质部空间占用总变化的57-73%,仅系统发育就占变异的50%以上。这些结果有助于我们了解木材结构功能,并与更好地了解森林对气候变化的响应有关。
    Investigating space allocation patterns of plant secondary xylem along a latitudinal gradient is useful to evaluate structure-function tradeoffs in woody angiosperm xylem. An anatomical dataset including 700 woody angiosperm species across China was compiled together with latitudinal and climate data for each species. The relative tissue fractions of vessels, fibers, and parenchyma (including ray and axial parenchyma) in xylem were analyzed to determine the effect of latitudinal differences and phylogeny on anatomical variation. The analyses revealed a trade-off between vessel and non-vessel fraction across latitude, with tissue fraction trade-offs mainly occurring between vessels and fibers, and between fibers and total parenchyma. Among 13 climate variables, thermal indices generally had greater explanatory power than moisture indices in bi-variate models for all cell types, while mean annual temperature, mean temperature of the coldest month, and annual actual evapotranspiration were included in the top multi-variate models explaining variance of different tissue fractions. Phylogeny and climate together explained 57-73% of the total variation in xylem space occupancy, with phylogeny alone accounting for over 50% of the variation. These results contribute to our knowledge of wood structure-function and are relevant to better understand forest response to climate change.
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  • 文章类型: Case Reports
    颅内起源的非霍奇金淋巴瘤(NHL)非常罕见,约占原发性中枢神经系统淋巴瘤(PCNSL)的1-2%。弥漫性大B细胞淋巴瘤(DLBCL)是最常见的NHL亚型,主要见于免疫功能低下的患者。因此,在具有免疫能力的患者中,巨大的孤立性DLBCL的发生令人困惑。我们介绍了一例68岁的男子,他在我们的设施中入院,有“两(2)个月的失忆症”的病史。磁共振成像(MRI)显示双侧额叶和call体约5.4cm*4.6cm*3.8cm占位性病变,肿块周围有混合信号强度和血管源性水肿。放射学,在组织病理学研究显示DLBCL之前,该肿块被误认为是脑膜瘤.巨大的孤立性原发性颅内淋巴瘤非常罕见,即使是经验丰富的放射科医生或神经外科医生,也可能是脑膜瘤,因为PCNSL的放射学特征可能非常不明确。由于我们病例的巨大和孤立性,我们实现了完全切除。当患者免疫受损时,PCNSL的预后通常很差。在有免疫能力的患者中,他们通过手术和化疗得到了很好的管理,总体生存率和生活质量可以非常令人鼓舞。
    Non-Hodgkin\'s lymphomas (NHL) with intracranial origin are very rare and constitutes about 1-2% of primary central nervous system lymphomas (PCNSL). Diffuse large B cell lymphoma (DLBCL) is the most common subtype of NHL and mostly seen in immunocompromised patients. Therefore, the occurrence of giant solitary DLBCL in an immunocompetent patient is puzzling. We present a case of 68-year-old man who was admitted at our facility with a history of \"hypomnesia of two (2) months\" duration. Magnetic resonance imaging (MRI) revealed a space occupying lesion in the bilateral frontal lobe and corpus callosum measuring about 5.4cm * 4.6cm * 3.8cm with mixed signal intensities and vasogenic edema around the mass. Radiological, this mass was mistaken for meningioma until histopathological studies revealed DLBCL. Giant solitary primary intracranial lymphomas are very rare and can be mistake for meningioma even with very experience radiologist or neurosurgeon since the radiological features of PCNSL can be very unspecific. We achieved to total resection because of the giant and solitary nature of our case. The prognosis of PCNSL is general very poor when the patient is immunocompromised. In immunocompetent patients, who are well managed with surgery and chemotherapy, the overall survival and quality of life can very encouraging.
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  • 文章类型: Case Reports
    Nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) in patients with multiple endocrine neoplasia type 1 (MEN1), which results from a mutation in the MEN1 gene, are commonly small, multiple tumors located in the pancreatic head and inside the pancreatic parenchyma. We herein describe a 35-year-old woman with bone pain and a 7-year history of a prolactinoma. She was clinically diagnosed with MEN1 based on the presence of the prolactinoma and parathyroid hyperplasia. Abdominal computed tomography revealed a 5-cm mass close to the splenic hilum. This soft tissue tumor, which was located outside the pancreatic parenchyma and the tissue origin of which could not be identified preoperatively, was found to be connected to the pancreatic tail. After resection, histological examination revealed a well-differentiated neuroendocrine tumor of pancreatic origin. Genetic testing revealed a heterozygous transition mutation of guanine to adenine at the coding nucleotide 133 in exon 2 (c.133G>A), resulting in an amino acid substitution of glutamic acid with lysine (E45K) in the MEN1 gene. This patient with MEN1 presented with a clinical condition involving a single non-metastatic NF-pNET located outside the pancreatic parenchyma with a missense mutation in the MEN1 gene, which could easily have been misdiagnosed as an accessory spleen.
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  • 文章类型: Case Reports
    Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare and fatal disease with no special clinical manifestations. Here, we report the dynamic brain magnetic resonance imaging (MRI) changes in a 30-year-old female PDLG patient over a 10-month period. MRI showed aggressive dilation of the subarachnoid space and the ventricular system, numerous encapsulated cysts in the subarachnoid space and the dilated cerebral sulci, diffuse reticulated or focal nodular enhancement in the subarachnoid space, as well as overall enhancement in the cystic walls. In addition to the aforementioned PDLG pathological findings, MRI also revealed non-contrasted solid lesions and a contrasted cyst-like lesion in the paraventricular areas. The dynamic and multiform neuroradiological changes help us to understand the pathological process of PDLG. Of particular interest is the discovery that parenchymal infiltration can occur in PDLG.
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  • 文章类型: Journal Article
    薄壁组织是木本被子植物次生木质部边材中至关重要的活组织。考虑到薄壁组织和水运输容器之间的各种相互作用,我们假设两种细胞类型之间的结构-功能关系。通过基于文献中得出的2,332种木质被子植物的广义加性混合模型方法,我们探讨了射线的比例和空间分布与轴向实质和血管大小之间的关系,同时控制最大植物高度和一系列气候因素。当考虑最大植物高度时,我们发现随着年平均气温的升高,平均血管直径与轴向实质比例和排列呈正相关,但不是为了雷薄壁组织.具有高轴向薄壁组织分数的物种倾向于具有宽血管,大部分薄壁组织都挤在血管周围,而具有小直径血管的物种显示出与血管不直接连接的轴向实质数量减少。这一发现为大型脉管种中轴实质和射线实质的独立功能提供了证据,并进一步支持了轴实质在长距离木质部水运输中的重要作用。
    Parenchyma represents a critically important living tissue in the sapwood of the secondary xylem of woody angiosperms. Considering various interactions between parenchyma and water transporting vessels, we hypothesize a structure-function relationship between both cell types. Through a generalized additive mixed model approach based on 2,332 woody angiosperm species derived from the literature, we explored the relationship between the proportion and spatial distribution of ray and axial parenchyma and vessel size, while controlling for maximum plant height and a range of climatic factors. When factoring in maximum plant height, we found that with increasing mean annual temperatures, mean vessel diameter showed a positive correlation with axial parenchyma proportion and arrangement, but not for ray parenchyma. Species with a high axial parenchyma tissue fraction tend to have wide vessels, with most of the parenchyma packed around vessels, whereas species with small diameter vessels show a reduced amount of axial parenchyma that is not directly connected to vessels. This finding provides evidence for independent functions of axial parenchyma and ray parenchyma in large vesselled species and further supports a strong role for axial parenchyma in long-distance xylem water transport.
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  • 文章类型: Case Reports
    OBJECTIVE: The aim of this case report is to discuss the clinicopathological features of a patient with a primary renal carcinoid tumor.
    METHODS: We report on the clinical and pathological information of one case of a patient with a primary renal carcinoid tumor as well as review relative literature.
    RESULTS: The patient was diagnosed with a renal tumor when she received physical examination, and exhibited no positive symptoms. The diameter of tumor was 5 cm, the cross surface of the tumor was light yellow and firm, and the central part was soft with hemorrhage and necrosis. Immunohistochemical staining revealed strong and diffuse staining with synaptophysin, chromogranin A, and neuron-specific enolase.
    CONCLUSIONS: A primary renal carcinoid tumor is extremely rare. Surgical resection is a preferred therapeutic method.
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  • 文章类型: Journal Article
    目标:近年来,相当多的努力集中在将木材解剖学和关键生态特征联系起来。分析大型数据库的研究描述了这些生态特征如何随着与传导和支持相关的木材解剖特征而变化。但没有考虑这些功能如何与参与水和碳水化合物储存的细胞(即薄壁组织细胞)相互作用。
    方法:我们分析了,在系统发育的背景下,执行三种木质部功能中每一种功能的细胞类型之间的功能关系(传导,支撑和储存)和木材密度和理论电导率,使用大约的样品。800种来自中国。
    结果:轴向实质和射线具有不同的进化相关模式。在高传导能力和大量轴向薄壁组织之间发现了进化联系,这可能与储水能力和栓塞修复有关。而大量的射线组织随着机械支撑的增加和水力能力的降低而进化。在系统发育主成分分析中,轴向薄壁组织与传导能力增加以及射线与木材密度的这种关联代表了正交的变化轴。在多变量空间中,然而,射线的比例可能与电导呈正相关,与木材密度呈负相关,表明这些轴在具有宽射线的物种中的灵活性。
    结论:研究结果表明,薄壁组织类型可能在功能上有所不同。不同细胞类型代表的功能轴在谱系之间是保守的,表明在被子植物的生态策略中具有重要作用。
    OBJECTIVE: In recent years considerable effort has focused on linking wood anatomy and key ecological traits. Studies analysing large databases have described how these ecological traits vary as a function of wood anatomical traits related to conduction and support, but have not considered how these functions interact with cells involved in storage of water and carbohydrates (i.e. parenchyma cells).
    METHODS: We analyzed, in a phylogenetic context, the functional relationship between cell types performing each of the three xylem functions (conduction, support and storage) and wood density and theoretical conductivity using a sample of approx. 800 tree species from China.
    RESULTS: Axial parenchyma and rays had distinct evolutionary correlation patterns. An evolutionary link was found between high conduction capacity and larger amounts of axial parenchyma that is probably related to water storage capacity and embolism repair, while larger amounts of ray tissue have evolved with increased mechanical support and reduced hydraulic capacity. In a phylogenetic principal component analysis this association of axial parenchyma with increased conduction capacity and rays with wood density represented orthogonal axes of variation. In multivariate space, however, the proportion of rays might be positively associated with conductance and negatively with wood density, indicating flexibility in these axes in species with wide rays.
    CONCLUSIONS: The findings suggest that parenchyma types may differ in function. The functional axes represented by different cell types were conserved across lineages, suggesting a significant role in the ecological strategies of the angiosperms.
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