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61.
We examined the depth-wise distribution of microfungi through 0–50-cm crusted sandy and playa profiles at the Nizzana research site, the Negev desert, Israel. A total of 188 species from 77 genera was isolated using the soil dilution plate method. Density of microfungal isolates sharply decreased with depth highly positively correlating with organic matter content at the sandy profiles. High load of solar radiation (at the surface) as well as strongly limited aeration, water infiltration, and increased salinity (at the playa depth) led to dominance of melanin-containing species with large, multicellular conidia both in the topsoil of all profiles and in the deep playa layers, while at 1–30 cm, species producing light-colored small one-celled conidia mostly prevailed. In that way, the above vertical variations resemble differences in the composition of topsoil microfungal communities found between the sites located in the Negev desert and in the Mediterranean region of Israel.  相似文献   
62.
Diagnosing amyloid goitre with thyroid aspiration biopsy   总被引:1,自引:0,他引:1  
OBJECTIVE: The aim of the study was to evaluate the value of fine needle aspiration biopsy of the thyroid as a tool for diagnosing amyloid goitre and assess how amyloidosis affects thyroid tissue and thyroid function. METHODS: Clinical and laboratory evaluation of 50 patients with secondary systemic amyloidosis was done, and goitre was found in 38 of them. All 38 patients underwent thyroid aspiration biopsy. Tissue samples were stained with haematoxylin and eosin, May-Grünwald-Giemsa, crystal violet and Congo red. RESULTS: Of the 38 cases of amyloid goitre, 10 showed euthyroid sick syndrome, two showed primary hyperthyroidism, two showed hypothyroidism and one showed subacute thyroiditis. The serum levels of thyroid hormones and thyroid-stimulating hormone were normal in the remaining patients. Thirty-five of the 38 patients (92%) showed amyloidosis after thyroid aspiration. One of these patients had papillary carcinoma in addition to amyloid goitre. Ten patients underwent subtotal thyroidectomy, and one patient underwent total thyroidectomy after aspiration. Microscopic evaluation revealed that the thyroid parenchyma in all patients was largely replaced with amyloid and adipose tissue. CONCLUSION: Fine needle aspiration of the thyroid is a valuable and sensitive method for diagnosing amyloid goitre, especially because it is a safe and easily performed procedure. Further, amyloid goitre has no significant influence on thyroid function even when it causes extensive parenchyma replacement.  相似文献   
63.
Abstract

Eccentric contractions are skeletal muscle stretches with concurrent active force production; these contractions commonly occur during dynamic sports activities and can cause acute muscle injury. Recovery from this injury depends in part on pro-inflammatory processes, such as neutrophil infiltration at the injured site, which is affected by estrogen. This estrogen effect has been examined broadly, but without distinguishing between major compartments within muscle in which neutrophil infiltration can occur. Therefore, we compared neutrophil antigen expression in two compartments of eccentrically contracted muscle of ovariectomized mice with or without estrogen. To quantify neutrophil antigen expression, serial cross sections of muscle were immunolabeled with antibodies that recognize 7/4 or Ly6C/G, then quantified using computer-assisted image analysis. At 48 h post injury, estrogen-positive (E+) mice had more 7/4-positive and Ly6C/G-positive myofibers, increased 7/4 area percentage, and more 7/4-positive cells in the connective tissue. In addition, E+ mice showed more 7/4-positive myofibers that were Ly6C/G-negative and more Ly6C/G-positive myofibers that were 7/4-negative. These data suggest that in injured muscle, estrogen increases 7/4 antigen in connective tissue and myofibers and is associated with more Ly6C/G-positive myofibers when the 7/4 antigen is absent from these myofibers.  相似文献   
64.
为探究生物质炭添加对喀斯特地区土壤水分入渗特性的影响,本研究以坡耕地黄壤为对象,采用室内土柱模拟的方法,研究不同添加量(质量分数为0、1%和2%)和不同粒径(粒径大小为<0.25、0.25~1和>1 mm)生物质炭添加下土壤水分累计入渗量、入渗速率及湿润锋进程的变化特征,并对入渗过程进行模拟。结果表明: 在定容重条件下,添加生物质炭后土壤的入渗过程明显受到抑制,添加生物质炭土壤的累计入渗量和入渗速率显著低于未添加生物质炭土壤,生物质炭添加量为1%和2%土壤的累计入渗量和入渗速率无显著差异。不同粒径生物质炭添加下,土壤累计入渗量从大到小依次表现为<0.25、0.25~1和>1 mm。与CK相比,当添加量为1%时,土壤300 min累计入渗量分别下降20.9%、35.2%和45.0%;当添加量为2%时,分别下降21.5%、37.5%和44.2%,说明大粒径生物质炭对土壤入渗的抑制作用显著强于小粒径生物质炭。土壤湿润锋进程对不同含量和不同粒径生物质炭添加的响应趋势与累计入渗量的变化趋势基本一致。Horton和Kostiakov模型能够用于模拟本研究中的土壤水分入渗过程,Horton模型拟合精度高,R2最大(0.91~0.98),均方根误差(RMSE)最小(0.14~0.21),而Kostiakov模型拟合得到的初始入渗速率更接近实测结果。研究结果可为生物质炭的合理施用提供科学依据,也可为喀斯特坡耕地土壤改良和水土保持提供有益参考。  相似文献   
65.
探讨分泌型磷蛋白1 (Secreted Phosphoprotein 1,SPP1)在头颈部鳞状细胞癌(Head and neck squamous cell carcinoma, HNSC)中与免疫浸润及临床的相关性,明确SPP1在HNSC预后和个体化治疗中的潜在价值。使用癌症基因组图谱(The Cancer Genome Atlas,TCGA)HNSC数据分析SPP1表达。使用来自TCGA的临床生存数据评估SPP1的临床预后价值。使用R语言的clusterProfiler 包进行SPP1相关的富集分析。使用R语言的CIBERSORT函数评估22种肿瘤浸润免疫细胞在HNSC中的浸润情况,分析肿瘤浸润免疫细胞与SPP1表达之间的关联。差异表达分析发现SPP1在HNSC中高表达(P<0.001),临床相关性分析发现SPP1表达与T分期(P=0.001)、临床分期(P=0.013)相关,SPP1高表达患者的总生存期明显短于低表达患者(P=0.020 4)。基因富集分析发现SPP1在HNSC中与免疫学功能及免疫相关通路有关联。肿瘤浸润免疫细胞分析发现在高SPP1表达组中,M2巨噬细胞(P=0.001 1)、未活化树突状细胞(P=0.005 5)、活化肥大细胞(P=0.048 8)浸润比例增加,而活化记忆性CD4+ T淋巴细胞(P<0.001)、浆细胞(P=0.026 6)、未活化肥大细胞(P=0.038 6)浸润比例减少。研究表明 SPP1在HNSC中充当致癌基因,并与患者的临床结果相关,SPP1在肿瘤免疫微环境中起重要作用,可能成为HNSC中有价值的预后生物标志物及免疫治疗生物靶标。  相似文献   
66.
The endoplasmic reticulum (ER) is an organelle important for protein synthesis and folding, lipid synthesis and Ca2+ homoeostasis. Consequently, ER stress or dysfunction affects numerous cellular processes and has been implicated as a contributing factor in several pathophysiological conditions. Tunicamycin induces ER stress in various cell types in vitro as well as in vivo. In mice, a hallmark of tunicamycin administration is the development of fatty livers within 24–48 hrs accompanied by hepatic ER stress. We hypothesized that tunicamycin would induce ER stress in adipose tissue that would lead to increased lipolysis and subsequently to fatty infiltration of the liver and hepatomegaly. Our results show that intraperitoneal administration of tunicamycin rapidly induced an ER stress response in adipose tissue that correlated with increased circulating free fatty acids (FFAs) and glycerol along with decreased adipose tissue mass and lipid droplet size. Furthermore, we found that in addition to fatty infiltration of the liver as well as hepatomegaly, lipid accumulation was also present in the heart, skeletal muscle and kidney. To corroborate our findings to a clinical setting, we examined adipose tissue from burned patients where increases in lipolysis and the development of fatty livers have been well documented. We found that burned patients displayed significant ER stress within adipose tissue and that ER stress augments lipolysis in cultured human adipocytes. Our results indicate a possible role for ER stress induced lipolysis in adipose tissue as an underlying mechanism contributing to increases in circulating FFAs and fatty infiltration into other organs.  相似文献   
67.
肥胖与慢性炎症   总被引:1,自引:0,他引:1  
孙波  李辉  王宁 《生物学杂志》2012,29(2):88-90
肥胖及其相关的代谢类疾病严重影响人类的健康,而肥胖诱导的慢性炎症是胰岛素抵抗和代谢综合症发病的关键因素.脂肪组织慢性炎症发生的机制及其与代谢综合症的关系已经成为全球瞩目的研究热点.慢性炎症的特征主要包括脂肪组织中促炎细胞因子表达量增加,抗炎细胞因子表达量降低以及大量巨噬细胞浸润.鉴于肥胖及其相关代谢综合症对人类健康的巨大危害,现对慢性炎症的发生机制,肥胖和慢性炎症之间的关系,脂肪组织炎症中巨噬细胞浸润以及和信号传导通路进行综述.  相似文献   
68.
Preferential movement of water in macropores plays an important role when the process of ponded infiltration in natural porous systems is studied. For example, the detailed knowledge of water flow through macropores is of a major importance when predicting runoff responses to rainfall events. The main objectives of this study are to detect preferential movement of water in Chernozem soil and to employ numerical modeling to describe the variably saturated flow during a field ponded infiltration experiment. The infiltration experiment was performed at the Macov experimental station (Calcari-Haplic Chernozem in Danubian Lowland, Slovakia). The experiment involved single ring ponded infiltration. At the quasi steady state phase of the experiment dye tracer was added to the infiltrating water. Then the soil profile was excavated and the penetration pattern of the applied tracer was recorded. The abundance of biopores as a product of fauna and flora was found. To quantify the preferential flow effects during the infiltration experiment, three-dimensional axisymmetric simulations were carried out by a two-dimensional dual-continuum numerical model. The water flow simulations based on measured hydraulic characteristics without consideration of preferential flow effects failed to describe the infiltration experiment adequately. The 3D axisymmetric simulation based on dual-permeability approach provided relatively realistic space-time distribution of soil water pressure below the infiltration ring.  相似文献   
69.
渝北水源区水源涵养林构建模式对土壤渗透性的影响   总被引:16,自引:0,他引:16  
赵洋毅  王玉杰  王云琦  赵占军  吴云  陈林 《生态学报》2010,30(15):4162-4172
土壤渗透性是评价土壤水源涵养作用重要指标之一,其受制于许多外在和内在因素的影响,与植被类型、土壤结构、土壤种类和降雨强度等关系密切。为探讨不同构建模式水源涵养林对土壤渗透性能的影响,以裸地为对照,以土壤初渗速率,稳渗速率,平均渗透速率和渗透总量表征土壤渗透性,对重庆北部水源区8种不同构建模式的水源涵养林地的土壤渗透性及其与理化性质的关系进行研究。结果表明:不同模式水源林地和同一模式林地不同层次土壤渗透性能存在较大差异,各林地土壤渗透性随土壤深度的增加而降低,母质层土壤渗透性受林分类型和林分结构等外界条件的干扰较小,差异不显著;8种林地土壤渗透性均好于裸地,各林地土壤渗透性能大小依次为:广东山胡椒×杉木混交林马尾松×柳杉混交林(火烧迹地)四川大头茶×四川山矾混交林毛竹×四川山矾×马尾松混交林马尾松×广东山胡椒混交林马尾松×四川大头茶混交林广东山胡椒×四川杨桐混交林毛竹纯林裸地,根据土壤渗透能力可将8种模式林分类型分为4类:第1类,广东山胡椒×杉木混交林和马尾松×柳杉混交林,土壤渗透性最好;第2类,四川大头茶×四川山矾混交林,土壤渗透能力较好;第3类,毛竹×四川山矾×马尾松混交林、马尾松×广东山胡椒混交林、广东山胡椒×四川杨桐混交林、马尾松×四川大头茶混交林,土壤渗透性好;第4类,毛竹林和裸露地,土壤渗透性最差。以广东山胡椒和杉木混交的林分模式的土壤渗透性最好,毛竹纯林地最差,毛竹纯林对提高土壤渗透性作用较差,营林时适当增加毛竹林中其他树种的混交比例可增强林地土壤渗透性能。通用经验方程对各林分土壤入渗过程的拟合效果最好,比较适用于描述本研究区域水源涵养林地土壤入渗特征的模型,Kostiakov方程拟合效果次之,Horton方程最差;结合相关分析,筛选出9个极显著或显著影响土壤渗透性能的土壤理化性质因子,通过主成分分析法,得到土壤渗透性能综合参数α及与其极显著相关因子的综合参数β,并构建土壤渗透性各指标及其综合参数α与β的线性回归模型,为重庆北部的水源涵养林建设和防治水土流失提供理论依据。  相似文献   
70.
再生水浇灌方式对芦苇地土壤水文生态特性的影响   总被引:3,自引:0,他引:3  
夏江宝  谢文军  陆兆华  贾琼  董立杰 《生态学报》2010,30(15):4137-4143
为提高再生水资源在芦苇群落生态恢复中的高效利用,采用温室内模拟实验的方法,以未灌溉(CK)为对照,对再生水(FS)、再生水清水轮灌(QF)及清水灌溉(QS)等3种浇灌方式下的芦苇地盐碱含量及水文物理参数进行测定分析,以其阐明不同浇灌方式下芦苇地的土壤水文生态效应。结果表明:清水灌溉、清废轮灌降盐压碱效果显著(P0.001),而再生水灌溉后土壤含盐量增加12.8%。与未灌溉相比,3种浇灌方式均使土壤容重减小,孔隙度增大,改善土壤水文物理效果表现为清废轮灌清水灌溉再生水灌溉。Horton模型比较适合描述灌溉后芦苇地土壤水分入渗过程,清水灌溉、清废轮灌改善了土壤水分的渗透性能,初渗率和稳渗率均比未灌溉增加,而再生水灌溉后初渗率下降15.0%。3种浇灌方式均能增强芦苇地贮蓄和保持土壤水分的能力,清废轮灌、清水灌溉、再生水灌溉的饱和蓄水量分别比未灌溉增加11.5%、4.3%、2.4%,涵蓄降水和供植物生长有效水分贮存能力表现为清废轮灌最好,其次为清水灌溉,而再生水灌溉则较差。  相似文献   
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