963 resultados para leaf tissue density


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Effect of aqueous leaf extracts of Catheranthus roseus, Calotropis gigantium and Datura stromoneum on common carp, Cyprinus carpio were investigated. C. carpio were separately fed with 1 and 2% aqueous extracts of these three plant leaves for a period of seven days. In 1% Catheranthus roseus of leaf extract fed group no significant tissue level changes were recorded. One and 2% of other two species fed treated group showed mild to severe necrotic and cellular changes in liver, kidney and spleen. Immunologically, significant rise in antibody titre and respiratory burst activity was recorded for 1% Catheranthus roseusfed group.

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土壤是人类赖以生存的自然环境和农业生产的重要资源,世界面临的粮食、资源和环境问题与土壤密切相关,目前危害土壤的主要因素是干旱和重金属污染。杨树具有适应性强、生长快和丰产等特性,本论文以青杨组杨树为模式植物,采用植物生态、生理及生物化学等方法,研究杨树对土壤干旱和锰胁迫的生态生理反应以及种群间差异,研究成果可为我国干旱半干旱地区营造人工林、防止沙漠化提供理论依据,也为恢复与重建重金属污染地区退化生态系统提供科学指导。主要研究结果如下: 1. 青海杨不同种群对干旱胁迫的响应差异 干旱胁迫显著降低了两个青海杨种群(干旱种群和湿润种群)生物量积累,包括株高、基径、干物质积累等,通过植物结构的调整,有更多的生物量向根部分配。干旱胁迫还显著降低了叶绿素和类胡萝卜素含量,增加了游离脯氨酸和总氨基酸含量。另一方面,干旱胁迫诱导了活性氧的积累,作为第二信使,激活了抗氧化系统,包括抗坏血酸(ASA)含量和酶系统如超氧化物歧化酶(SOD),愈创木酚过氧化物酶(GPX),抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)。这样,杨树既有避旱机制又有耐旱机制,使其在干旱胁迫下有相当程度的可塑性。与湿润种群相比,干旱种群杨树有更多的生物量分配到根部,积累了更多的游离脯氨酸和总氨基酸来进行渗透调节,并且有更有效的抗氧化系统,包括更高含量的ASA 和更高活性的APX 和GR,这些使得干旱种群杨树比湿润种群杨树对干旱有更好的耐性。 2. 喷施硝普钠(SNP)对青海杨阿坝种群干旱胁迫耐性的影响 干旱胁迫显著的降低了青海杨阿坝种群的生长和生物量积累以及叶片相对含水量,还诱导了脯氨酸的合成以进行渗透调节。干旱胁迫下过氧化氢(H2O2)显著累积从而造成对膜脂和蛋白的伤害,使得丙二醛和蛋白羰基含量升高。干旱胁迫下喷施SNP可以减轻干旱胁迫造成的伤害,包括增加叶片的相对含水量,增加脯氨酸和总氨基酸的积累,并激活抗氧化酶系统如SOD,GPX和APX,从而减少丙二醛(MDA)和蛋白羰基(C=O)的积累,但是在水分良好情况下SNP的效果不显著。 3. 青杨不同种群对锰胁迫的生长与形态响应差异 在同一锰浓度下,干旱种群的耐性指数都要高于湿润种群,这表明青杨对干旱和高锰胁迫具有交叉耐性。两个种群的株高,生物量和叶绿素含量都随锰浓度的升高而逐渐下降。就累积浓度而言,0 和0.1 mM 锰胁迫下,干旱种群积累的锰浓度要高于湿润种群,而在高浓度锰胁迫下(0.5 和1 mM),湿润种群要高于干旱种群。在0,0.1 和0.5 mM下,锰大多积累在根中,叶片次之,茎中最少。而在1 mM,锰更多的积累在叶片中。就累积总量而言,在各个锰浓度胁迫下,根,茎和叶相比,两个种群青杨都是叶片累积的锰总量要高于根和茎。两个种群间比较,对照中没有显著区别,0.1 mM 锰胁迫下,湿润种群根中累积的锰要高于干旱种群,而在地上部中,干旱种群要高于湿润种群。而0.5 和1 mM 锰胁迫下,根、叶、茎+叶、根+茎+叶中,锰累积总量都是湿润种群高于干旱种群。锰胁迫下,青杨叶片数和叶面积包括总叶面积和平均叶面积都显著降低。叶片横切面的光学显微观察结果表明未经锰胁迫的栅栏组织的细胞饱满,海绵组织发达、清晰;胁迫后杨树叶片栅栏组织细胞出现不同程度的皱缩,海绵组织几乎不可见,此外还发现输导组织在胁迫下密度变小和分生组织严重割裂等现象。 4. 青杨不同种群对锰胁迫的生理与生化响应差异 青杨两个种群脱落酸(ABA)含量在锰胁迫下都显著增加,干旱种群的增幅更大。三种多胺含量在锰胁迫下显示了不同的响应趋势:腐胺在两个种群的各个锰处理下都增加,亚精胺只在干旱种群中显著增加,而精胺除了干旱种群在1 mM 下有所增加外,在锰胁迫下变化很小。谷胱甘肽含量随锰浓度升高而增加,在0.5 mM 锰时达到最高值,1mM 时有所下降。植物络合素(PCs)含量与非蛋白巯基(NP-SH)趋势相似,随锰浓度的升高而增加,且干旱种群中含量要高于湿润种群。锰处理还引起氧化胁迫,表现为过氧化氢和丙二醛含量增加。SOD 活性在湿润种群中,在0 到0.5 mM 锰胁迫下活性升高,但在1 mM 锰胁迫时,其活性有所下降。而在干旱种群中,SOD 活性变化较小,并始终维持在一个较高的水平。APX 活性在两个种群中都随锰浓度的升高而增加,干旱种群活性要高于湿润种群。锰胁迫还显著增加了酚类物质的含量,同时GPX 和多酚氧化酶(PPO)活性也随锰浓度的升高而增加。干旱种群的酚类含量和GPX 与PPO 活性都要高于湿润种群。锰胁迫还改变了氨基酸的含量和构成,根据锰胁迫下浓度变化的不同,可以将游离氨基酸分为三组:第一组包括,谷氨酸,丙氨酸和天门冬氨酸,这一组氨基酸含量在锰胁迫下有所下降。第二组包括缬氨酸,亮氨酸和苏氨酸含量在锰胁迫下基本不变化或变化很小。剩下的氨基酸为第三组,这组氨基酸含量在锰胁迫下显著增加,而根据增加的幅度又可以将它们分为两个亚组,丝氨酸,酪氨酸,苯丙氨酸,组氨酸和脯氨酸,在1 mM 下的含量是对照的4 倍以上。异亮氨酸,赖氨酸,精氨酸和甘氨酸含量在1 mM 下是对照含量的2 倍以下。同时,同一锰浓度下,干旱种群比湿润种群积累的氨基酸含量要高。 Soil is the indispensable environment for human survival and important resource foragriculture development. Food and environmental problems facing the world are all closelyrelated to soil and nowadays it is threatened by many factors, among which drought stress andheavy metal pollution are the most serious ones. Poplars (Populus spp.) are importantcomponents of ecosystem and suitable as a source of fuel, fiber and lumber due to their fastgrowth. In this study, different populations of Section Tacamahaca spach were used as modelplants to investigate the adaptability to drought stress and manganese toxicity and differencesbetween populations from dry and wet climate regions. Our results can provide theoreticalevidence for the afforestation and prevention of desertification in the arid and semi-arid areas,and also can supply scientific direction for the reconstruction and rehalibitation of ecosystemscontaminated by heavy metals. The results are as follows: 1. Differences in ecophysiological responses to drought stress in two contrastingpopulations of Populus przewalskii Drought stress not only significantly affected dry mass accumulation and allocation, butalso significantly decreased chlorophyll pigment contents and accumulated free proline andtotal amino acids. On the other hand, drought also significantly increased the levels ofabscisic acid and reactive oxygen species, as secondary messengers, to induce the entire set ofantioxidative systems including the increase of reduced ascorbic acid content and the activities of superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase and glutathioneredutase. Thus the combination of drought avoidance and tolerance mechanisms conferredpoplar a high degree of plasticity in response to drought stress. Compared with the wetclimate population, the dry climate population showed lower dry matter accumulation andallocated more biomass to root systems, and accumulated more free proline and total aminoacids for osmotic adjustment. The dry climate population also showed more efficientantioxidant systems with higher content of ascorbic acid and higher activities of ascorbateperoxidase and glutathione redutase than the wet climate population. All these made the dryclimate population superior in adaptation to drought stress than the wet climate population. 2. Effect of exogenous applied SNP on drought tolerance in Populus przewalskii Drought stress significantly increased hydrogen peroxide content and caused oxidativestress to lipids and proteins assessed by the increase in malondialdehyde and total carbonylcontents, respectively. The cuttings of P. przewalskii accumulated proline and other aminoacids for osmotic adjustment to lower water potential, and activated the antioxidant enzymes such as superoxide dismutase, guaiacol peroxidase and ascorbate peroxidase to maintain thebalance of generation and quenching of reactive oxygen species. Moreover, exogenous SNPapplication significantly heightened the growth performance of P. przewalskii cuttings underdrought treatment by promotion of proline accumulation and activation of antioxidant enzymeactivities, while under well-watered treatment the effect of SNP application was very little. 3. Morphological responses to manganese toxicity in the two contrasting populations ofPopulus cathayana High concentration of manganese caused significant decrease in shoot height andbiomass accumulation. The tolerance index of the dry climate population was significantlyhigher than that of the wet climate population, suggesting the superior Mn tolerance in theformer and the existence of cross-tolerance of drought stress and high Mn toxicity. Injuries tothe leaf anatomical features were also found as the reduced thickness in palisade and spongyparenchyma, the decreased density in the conducting tissue and the collapse and split in themeristematic tissue in the central vein. As for the Mn concentrations in the plant tissues, under0, 0.1 and 0.5 mM, most of the Mn accumulated in the roots, then leaves, and stem the least, while under 1 mM, most of the Mn accumulated in the leaves. As far as the total amounts ofMn extraction are concerned, the leaf extracted more Mn than the root and stem in the twopopulations under various Mn concentrations. There is no difference between the twopopulations under control. Under 0.1 mM, the wet climate population extracted higher Mn inthe root than the dry climate population, while in the shoot, the dry climate populationextracted much more Mn. Under 0.5 and 1 mM, the wet climate population translocated moreMn both in the root and the shoot than the dry climate population. 4. Physiological and biochemical responses to manganese toxicity in the two contrastingpopulations of Populus cathayana Mn treatment resulted in oxidative stress indicated by the oxidation to lipids, proteinsand DNA. A regulated network of defence strategies was employed for the chelation,detoxification and tolerance of Mn including the enhanced synthesis of ABA and polyamines,the accumulation of free amino acids, especially His and Pro, and the activation of theenzymes superoxide dismutase and guaiacol peroxidase. Contents of non-protein thiol,reduced glutathione, phytochelatins and phenolics compounds and activities of superoxide dismutase, guaiacol peroxidase and polyphenol oxidase also increased significantly forantioxidant or chelation functions. The wet climate population not only accumulated lessabscisic acid, free amino acids, phytochelatins and phenolics compounds, but also exhibitedlower activities of superoxide dismutase, guaiacol peroxidase and polyphenol oxidase thusresulting in more serious oxidative damage and more curtained growth.

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Purpose: To determine the effects of carbon ion beams with five different linear energy transfer (LET) values on adventitious shoots from in vitro leaf explants of Saintpaulia ionahta Mauve cultivar with regard to tissue increase, shoots differentiation and morphology changes in the shoots. Materials and methods: In vitro leaf explant samples were irradiated with carbon ion beams with LET values in the range of 31 similar to 151 keV/mu m or 8 MeV of X-rays (LET 0.2 keV/mu m) at different doses. Fresh weight increase, surviving fraction and percentage of the explants with regenerated malformed shoots in all the irradiated leaf explants were statistically analysed. Results: The fresh weight increase (FWI) and surviving fraction (SF) decreased dramatically with increasing LET at the same doses. In addition, malformed shoots, including curliness, carnification, nicks and chlorophyll deficiency, occurred in both carbon ion beam and X-ray irradiations. The induction frequency with the former, however, was far more than that with the X-rays. Conclusions: This work demonstrated the LET dependence of the relative biological effectiveness (RBE) of tissue culture of Saintpaulia ionahta according to 50% FWI and 50% SF. After irradiating leaf explants with 5 Gy of a 221 MeV carbon ion beam having a LET value of 96 keV/mu m throughout the sample, a chlorophyll-deficient (CD) mutant, which could transmit the character of chlorophyll deficiency to its progeny through three continuous tissue culture cycles, and plantlets with other malformations were obtained.

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The effects of 960 MeV carbon ion beam and 8 MeV X-ray irradiation on adventitious shoots from in vitro leaf explants of two different Saintpaulia ionahta (Mauve and Indikon) cultivars were studied with regard to tissue increase, shoots differentiation and morphology changes in the shoots. The experimental results showed that the survival fraction of shoot formation for the Mauve and Indikon irradiated with the carbon ion beam at 20 Gy were 0.715 and 0.600, respectively, while those for both the cultivars exposed to the Xray irradiation at the same dose were 1.000. Relative biological effectiveness (RBE) of Mauve with respect to X-ray was about two. Secondly, the percentage of regenerating explants with malformed shoots in all Mauve regenerating explants irradiated with carbon ion beam at 20 Gy accounted for 49.6%, while that irradiated with the same dose of X-ray irradiation was only 4.7%; as for Saintpatdia ionahta Indikon irradiated with 20 Gy carbon ion beam, the percentage was 43.3%, which was higher than that of X-ray irradiation. Last, many chlorophyll deficient and other varieties of mutants were obtained in this study. Based on the results above, it can be concluded that the effect of mutation induction by carbon ion beam irradiation on the leaf explants of Saintpaulia ionahta is better than that by X-ray irradiation; and the optimal mutagenic dose varies from 20 Gy to 25 Gy for carbon ion beam irradiation.

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In many plant species, leaf morphology varies with altitude, an effect that has been attributed to temperature. It remains uncertain whether such a trend applies equally to juvenile and mature trees across altitudinal gradients in semi-arid mountain regions. We examined altitude-related differences in a variety of needle characteristics of juvenile (2-m tall) and mature (5-m tall) alpine spruce (Picea crassifolia Kom.) trees growing at altitudes between 2501 and 3450 m in the Qilian Mountains of northwest China. We found that stable carbon isotope composition (delta C-13), area- and mass-based leaf nitrogen concentration (N-a, N-m), number of stomata per gram of nitrogen (St/N), number of stomata per unit leaf mass (St/LM), projected leaf area per 100 needles (LA) and leaf mass per unit area (LMA) varied nonlinearly with altitude for both juvenile and mature trees, with a relationship reversal point at about 3 100 m. Stomatal density (SD) of juvenile trees remained unchanged with altitude, whereas SD and stomatal number per unit length (SNL) of mature spruce initially increased with altitude, but subsequently decreased. Although several measured indices were generally found to be higher in mature trees than in juvenile trees, N-m, leaf carbon concentration (C.), leaf water concentration. (LWC), St/N, LA and St/LM showed inconsistent differences between trees of different ages along the altitudinal gradient. In both juvenile and mature trees, VC correlated significantly with LMA, N-m, N-a, SNL, St/LM and St/N. Stomatal density, LWC and LA were only significantly correlated with delta C-13 in mature trees. These findings suggest that there are distinct ecophysiological differences between the needles of juvenile and mature trees that determine their response to changes in altitude in semi-arid mountainous regions. Variations in the fitness of forests of different ages may have important implications for modeling forest responses to changes in environmental conditions, such as predicted future temperature increases in high attitude areas associated with climate change.

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The extremely high level of solar radiation on the Qinghai-Tibet Plateau may induce photoinhibition and thus limit leaf carbon gain. To assess the effect of high light, we examined gas exchange and chlorophyll fluorescence for two species differing in light interception: the prostrate Saussurea superba and the erect-leaved Gentiana straminea. In controlled conditions with favorable water and temperature, neither species showed apparent photoinhibition in gas exchange measurements. In natural environment, however, their photosynthetic rate decreased remarkably at high light. Photosynthesis depression was aggravated under high leaf temperature or soil water stress. Relative stomatal limitation was much higher in S. superba than in G. straminea and it remarkably increased in the later species at midday when soil was dry. F-v/F-m as an indicator for photoinhibition was generally higher in S. superba than in the other species. F-v/F-m decreased significantly under high light at midday in both species, even when soil moisture was high. F-0 linearly elevated with the increment of leaf temperature in G. straminea, but remained almost constant in S. superba. Electron transport rate (ETR) increased with photosynthetically active photon flux density (PPFD) in S. superba, but declined when PPFD was high than about 1000 mumol m(-2) s(-1) in G. straminea. Compared to favorable environment, the estimated daily leaf carbon gain at PPFD above 800 mumol m(-2) s(-1) was reduced by 32% in S. superba and by 17% in G. straminea when soil was moist, and by 43% and 53%, respectively, when soil was dry. Our results suggest that the high radiation induces photoinhibition and significantly limits photosynthetic carbon gain, and the limitation may further increase at higher temperature and in dry soil.

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Wallace, Joanne, et al., 'Body composition and bone mineral density changes during a premier league season as measured by dual-energy X-ray absorptiometry', International Journal of Body Composition Research (2006) 4(2) pp.61-66 RAE2008

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The deposition of ultrasonic energy in tissue can cause tissue damage due to local heating. For pressures above a critical threshold, cavitation will occur in tissue and bubbles will be created. These oscillating bubbles can induce a much larger thermal energy deposition in the local region. Traditionally, clinicians and researchers have not exploited this bubble-enhanced heating since cavitation behavior is erratic and very difficult to control. The present work is an attempt to control and utilize this bubble-enhanced heating. First, by applying appropriate bubble dynamic models, limits on the asymptotic bubble size distribution are obtained for different driving pressures at 1 MHz. The size distributions are bounded by two thresholds: the bubble shape instability threshold and the rectified diffusion threshold. The growth rate of bubbles in this region is also given, and the resulting time evolution of the heating in a given insonation scenario is modeled. In addition, some experimental results have been obtained to investigate the bubble-enhanced heating in an agar and graphite based tissue- mimicking material. Heating as a function of dissolved gas concentrations in the tissue phantom is investigated. Bubble-based contrast agents are introduced to investigate the effect on the bubble-enhanced heating, and to control the initial bubble size distribution. The mechanisms of cavitation-related bubble heating are investigated, and a heating model is established using our understanding of the bubble dynamics. By fitting appropriate bubble densities in the ultrasound field, the peak temperature changes are simulated. The results for required bubble density are given. Finally, a simple bubbly liquid model is presented to estimate the shielding effects which may be important even for low void fraction during high intensity focused ultrasound (HIFU) treatment.

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Tissue microarrays assembled from control and multiple sclerosis (MS) brain tissue have been used to assess the expression patterns and cellular distribution of two antigens, the proinflammatory cytokine osteopontin and the inducible heat shock protein alpha B -crystallin, which have previously been implicated in MS pathogenesis. Tissue cores were taken from paraffin-embedded donor blocks containing chronic active or chronic inactive plaques and normal-appearing white matter (NAWM) in seven MS cases, and white matter (WM) in five control cases. Expression patterns of both proteins were assessed against myelin density and microglial activation in the different tissue categories. Both proteins showed increased expression in all categories of MS tissue compared with control WM. The results indicate progressive up-regulation of expression of osteopontin with increased plaque activity, while elevation of alpha B-crystallin expression in MS tissue was independent of demyelination. In MS NAWM a significant correlation was observed between high levels of expression of osteopontin and alpha B -crystallin. Osteopontin expression was predominantly confined to astrocytes throughout MS tissues. alpha B -crystallin was expressed on astrocytes, oligodendrocytes and occasionally on demyelinated axons. Taken together, these data indicate a wider distribution of osteopontin and alpha B -crystallin in MS tissues than previously described and support their proposed role in MS pathogenesis.

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Purpose: We characterized interleukin-8 (IL-8) and IL-8 receptor expression (CXCR1 and CXCR2) in prostate cancer to address their significance to this disease. Experimental Design: Immunohistochemistry was conducted on 40 cases of human prostate biopsy containing histologically normal and neoplastic tissue, excised from patients with locally confined or invasive androgen-dependent prostate cancer, and 10 cases of transurethral resection of the prostate material from patients with androgen-independent disease. Results: Weak to moderate IL-8 expression was strictly localized to the apical membrane of normal prostate epithelium. In contrast, membranous expression of IL-8, CXCR1, and CXCR2 was nonapical in cancer cells of Gleason pattern 3 and 4, whereas circumferential expression was present in Gleason pattern 5 and androgen-independent prostate cancer. Each of IL-8, CXCR1, and CXCR2 were also increasingly localized to the cytoplasm of cancer cells in correlation with advancing stage of disease. Cytoplasmic expression (but not apical membrane expression) of IL-8 in Gleason pattern 3 and 4 cancer correlated with Ki-67 expression (R = 0.79; P <0.001), cyclin D1 expression (R = 0.79; P <0.001), and microvessel density (R = 0.81; P <0.001). In vitro studies on androgen-independent PC3 cells confirmed the mitogenic activity of IL-8, increasing the rate of cell proliferation through activation of both CXCR1 and CXCR2 receptors. Conclusions: We propose that the concurrent increase in IL-8 and IL-8 receptor expression in human prostate cancer induces autocrine signaling that may be functionally significant in initiating and promoting the progression of prostate cancer by underpinning cell proliferation and angiogenesis.

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Lung T lymphocytes are important in pulmonary immunity and inflammation. it has been difficult to study these cells due to contamination with other cell types, mainly alveolar macrophages. We have developed a novel method for isolating lung T cells from lung resection tissue, using a combination of approaches. Firstly the lung tissue was finely chopped and filtered through a nylon mesh. Lymphocytic cells were enriched by Percoll density centrifugation and the T cells purified using human CD3 microbeads, resulting in 90.5% +/- 1.9% (n = 11) pure lymphocytes. The T cell yield from the crude cell preparation was 10.8 +/- 2.1% and viability, calculated using propidium iodide (PI) staining and trypan blue, was typically over 95%. The purification process did not affect expression of CD69 or CD103, nor was there a difference in the proportion of CD4 and CD8 cells between the starting population and the purified cells. Microarray analysis and real time RT-PCR revealed upregulation of GAPDH and CXCR6 of the lung T cells as compared to blood-derived T cells. This technique highly enriches lung T cells to allow detailed investigation of the biology of these cells. (C) 2008 Elsevier B.V. All rights reserved.

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Background: The phosphatidylinositol 3-kinase (PI3K)-AKT signal transduction pathway is critical to cell growth and survival. In vitro functional studies indicate that the candidate schizophrenia susceptibility gene DTNBP1 influences AKT signaling to promote neuronal viability. The AKT1 gene has also been implicated in schizophrenia by association studies and decreased protein expression in the brains of schizophrenic patients. 
 Methods: The association of DTNBP1 in the Irish Study of High Density Schizophrenia Families (ISHDSF) prompted our investigation of AKT1 for association with disease in this sample. Eight single nucleotide polymorphisms spanning AKT1 were analyzed for association with schizophrenia across four definitions of affection and according to Operational Criteria Checklist of Psychotic Illness (OPCRIT) symptom scales. We examined expression of AKT1 messenger RNA from postmortem brain tissue of schizophrenic, bipolar, and control individuals. 
 Results: No single marker showed significant association, but the risk haplotype previously found over-transmitted to Caucasian schizophrenic patients was significantly under-transmitted in the ISHDSF (.01 < p < .05), across all OPCRIT symptom dimensions. Exploratory haplotype analysis confirmed association with schizophrenia toward the 5’ end of AKT1 (.008 < p < .049, uncorrected). We found significantly decreased RNA levels in prefrontal cortex of schizophrenic individuals, consistent with reduced AKT1 protein levels reported in schizophrenic brain. 
 Conclusions: The replication of association of AKT1 gene variants in a further Caucasian family sample adds support for involvement of AKT signaling in schizophrenia, perhaps encompassing a broader clinical phenotype that includes mood dysregulation. We show that AKT signaling might be compromised in schizophrenic and bipolar patients via reduced RNA expression of specific AKT isoforms.

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Diabetes may induce both quantitative and qualitative changes in lipoproteins, especially low-density lipoprotein (LDL). Effects of LDL glycation on endothelial cell secretion of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) have not been fully elucidated. Human aortic endothelial cell (HAEC) tPA and PAI-1 production were determined after incubation with LDL (50 to 500 microg/mL protein, 24 h) from three sources: (1) nondiabetic LDL (N-LDL) modified in vitro to form six preparations: native, nonmodified (N); glycated (G); minimally oxidized (MO); minimally oxidized and glycated (MOG); heavily oxidized (HO); and heavily oxidized and glycated (HOG); (2) in vivo glycated and relatively nonglycated LDL subfractions from type 1 diabetic patients; (3) LDL from type 1 diabetic patients and matched controls, which was subfractionated using density gradient ultracentrifugation. In experiments using LDL modified in vitro, the rate of tPA release by HAECs incubated with N-LDL (83 +/- 4 ng/mg cell protein/24 h) did not differ significantly from those incubated with G-LDL (73 +/- 7), MO-LDL (74 +/- 13), or MOG-LDL (66 +/- 15) and was not influenced by LDL concentration. The rate of PAI-1 release was similar in HAECs incubated with N-LDL (5.7 +/- 0.6 mug/mg cell protein/24 h), G-LDL (5.7 +/- 0.7), MO-LDL (5.5 +/- 0.8), or MOG-LDL (5.7 +/- 0.9) and was not influenced by LDL concentration. In contrast, tPA release was significantly decreased in cells incubated with LDL (10 microg/mL) modified extensively by oxidation, and averaged 45.2 +/- 5.0 and 43.7 +/- 9.9 ng/mg/24 h for HO-LDL and HOG-LDL, respectively, and was further decreased with increasing concentrations of the heavily oxidized LDL preparations. PAI-1 release was not significantly decreased relative to N-LDL in cells incubated with low concentrations (5 to 50 microg/mL) of HO-LDL and HOG-LDL, but was decreased to 3.2 +/- 0.5 and 3.1 +/- 0.7 microg/mg/24 h for HO-LDL and HOG-LDL at 200 microg/mL, respectively. Results using in vivo glycated versus nonglycated LDL showed that tPA and PAI-1 release did not differ between subfractions. Release of tPA averaged 5.11 +/- 0.6 and 5.12 +/- 0.7 ng/mg/24 h, whereas release of PAI-1 averaged 666 +/- 27 ng/mg/24 h and 705 +/- 30 ng/mg/24 h for nonglycated and glycated LDL subfractions, respectively. Using LDL of different density subclasses, tPA and PAI-1 release in response to LDL from diabetic patients compared with control subjects did not differ when HAECs were incubated with LDLs of increasing density isolated from each subject pair. We conclude that oxidation of LDL, but not glycation, may contribute to the altered fibrinolysis observed in diabetes.