Expression of NEDD4L and ENaC in Urinary Extracellular Vesicles in Pre-eclampsia.

OBJECTIVE: To assess changes in expression of renal epithelial sodium channel (ENaC) and NEDD4L, a ubiquitin ligase, in urinary extracellular vesicles (UEV) of pre-eclamptic women compared to normal pregnant controls. METHODS: Urine was collected from pre-eclamptic women (PE, n = 20) or during normal pregnancy (NP, n = 20). UEV were separated by differential ultracentrifugation. NEDD4L, α-ENaC and γ-ENaC were identified by immunoblotting. RESULTS: There was no difference in the expression of NEDD4L (p = 0.17) and α-ENaC (p = 0.10). PE subjects showed increased expression of γ-ENaC by 6.9-fold compared to NP (p < 0.0001). CONCLUSION: ENaC expression is upregulated in UEV of pre-eclamptic subjects but was not associated with changes in NEDD4L.

Decreased tibial nerve movement in patients with failed back surgery syndrome and persistent leg pain.

PURPOSE: To measure and compare the total and normalised tibial nerve movements during forward bending in patients with and without failed back surgery syndrome (FBSS) and persistent leg pain following anatomically successful lumbar decompression surgery and demonstrated no psychological stress. Nerve pathomechanics may contribute to FBSS with persistent leg pain following anatomically successful lumbar decompression surgery. METHODS: Tibial nerve movement during forward bending was measured in two groups of patients following anatomically successful lumbar decompression surgery. FBSS group (N = 37) consisted of patients with persistent leg pain following lumbar surgery, and non-FBSS (N = 37) were patients with no remaining leg pain following lumbar surgery. Total and normalised tibial nerve movement at the popliteal fossa was measured by a previously validated ultrasound imaging technique and compared between the two groups, and also between the painful and non-painful leg within the FBSS group. RESULTS: Both the mean total and normalised tibial nerve movement were significantly decreased in the FBSS group in both legs when compared to the non-FBSS group (P < 0.05). The total and normalised tibial nerve movements were also more restricted in the painful leg (P < 0.05) when compared to the non-painful side within the FBSS group. CONCLUSION: This was the first study to quantify the decreased total and normalised tibial nerve mobility in FBSS patients with persistent leg pain when compared with non-FBSS patients following anatomically successful lumbar decompression surgery. Further research could investigate the efficacy of intervention, such as nerve mobilisation in this particular group of patients with failed back surgery syndrome and limited nerve mobility. These slides can be retrieved under Electronic Supplementary Material.

Increased expression and phosphorylation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoforms in urinary exosomes in pre-eclampsia.

BACKGROUND: Glycolysis is altered in various kidney diseases, but little is known about glycolysis in pre-eclampsia, a multi-system disorder with major pathological effects on the kidney. Urinary exosomes provide a non-invasive alternative for studying changes in kidney metabolism. This study aims to characterise the expression and phosphorylation of isozymes of the key glycolytic regulatory protein, 6-phosphofructokinase-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2), in urinary exosomes of subjects with pre-eclampsia (PE), compared to normotensive non-pregnant (NC) and normotensive pregnant (NP) controls. METHODS: A cross-sectional study of NC (n = 19), NP (n = 23) and PE (n = 29) subjects was performed. Exosomes were isolated from urine samples by differential ultracentrifugation, and then analyzed by Western blot and densitometry for expression of PFK-2/FBPase-2 isozymes (PFKFB2, PFKFB3 and PFKFB4) and phosphorylation of PFKFB2 at residues Ser483 and Ser466 and PFKFB3 at Ser461. RESULTS: PFKFB2 expression was increased 4.7-fold in PE compared to NP (p < 0.001). PFKFB2 phosphorylation at Ser483 was increased 2.6-fold in PE compared to NP (p = 0.002). Expression of phosphorylated PFKFB2/PFKFB3 at Ser466/Ser461 was increased in PE, being present in 77.4% (95% CI 59.9-88.9%) of PE and 8.3% (95% CI 1.2-27.0%) of NP samples (p < 0.001). PFKFB3 was more commonly expressed in PE, detected in 90.3% (95% CI 74.3-97.4%) of PE and 8.3% (95% CI 1.2-27.0%) of NP samples (p < 0.001). PFKFB4 had a 7.2-fold increase in expression in PE compared to NP (p < 0.001). No significant differences between NP and NC groups were observed. CONCLUSION: Regulatory proteins that increase glycolysis are increased in the urinary exosomes of subjects with pre-eclampsia, suggesting that renal glycolysis may be increased in this condition.

Realistic kinetic loading of the jaw system during single chewing cycles: a finite element study.

Although knowledge of short-range kinetic interactions between antagonistic teeth during mastication is of essential importance for ensuring interference-free fixed dental reconstructions, little information is available. In this study, the forces on and displacements of the teeth during kinetic molar biting simulating the power stroke of a chewing cycle were investigated by use of a finite-element model that included all the essential components of the human masticatory system, including an elastic food bolus. We hypothesised that the model can approximate the loading characteristics of the dentition found in previous experimental studies. The simulation was a transient analysis, that is, it considered the dynamic behaviour of the jaw. In particular, the reaction forces on the teeth and joints arose from contact, rather than nodal forces or constraints. To compute displacements of the teeth, the periodontal ligament (PDL) was modelled by use of an Ogden material model calibrated on the basis of results obtained in previous experiments. During the initial holding phase of the power stroke, bite forces were aligned with the roots of the molars until substantial deformation of the bolus occurred. The forces tilted the molars in the bucco-lingual and mesio-distal directions, but as the intrusive force increased the teeth returned to their initial configuration. The Ogden material model used for the PDL enabled accurate prediction of the displacements observed in experimental tests. In conclusion, the comprehensive kinetic finite element model reproduced the kinematic and loading characteristics of previous experimental investigations.

Weight-HbA1c-insulin-glucose model for describing disease progression of type 2 diabetes.

A previous semi-mechanistic model described changes in fasting serum insulin (FSI), fasting plasma glucose (FPG), and glycated hemoglobin (HbA1c) in patients with type 2 diabetic mellitus (T2DM) by modeling insulin sensitivity and ß-cell function. It was later suggested that change in body weight could affect insulin sensitivity, which this study evaluated in a population model to describe the disease progression of T2DM. Nonlinear mixed effects modeling was performed on data from 181 obese patients with newly diagnosed T2DM managed with diet and exercise for 67 weeks. Baseline ß-cell function and insulin sensitivity were 61% and 25% of normal, respectively. Management with diet and exercise (mean change in body weight = -4.1 kg) was associated with an increase of insulin sensitivity (30.1%) at the end of the study. Changes in insulin sensitivity were associated with a decrease of FPG (range, 7.8-7.3 mmol/L) and HbA1c (6.7-6.4%). Weight change as an effector on insulin sensitivity was successfully evaluated in a semi-mechanistic population model.

Heterogeneous growth-induced prestrain in the heart.

Even when entirely unloaded, biological structures are not stress-free, as shown by Y.C. Fung׳s seminal opening angle experiment on arteries and the left ventricle. As a result of this prestrain, subject-specific geometries extracted from medical imaging do not represent an unloaded reference configuration necessary for mechanical analysis, even if the structure is externally unloaded. Here we propose a new computational method to create physiological residual stress fields in subject-specific left ventricular geometries using the continuum theory of fictitious configurations combined with a fixed-point iteration. We also reproduced the opening angle experiment on four swine models, to characterize the range of normal opening angle values. The proposed method generates residual stress fields which can reliably reproduce the range of opening angles between 8.7±1.8 and 16.6±13.7 as measured experimentally. We demonstrate that including the effects of prestrain reduces the left ventricular stiffness by up to 40%, thus facilitating the ventricular filling, which has a significant impact on cardiac function. This method can improve the fidelity of subject-specific models to improve our understanding of cardiac diseases and to optimize treatment options.

Stress-whitening occurs in demineralized bone.

INTRODUCTION: The incidence of age-related bone fracture is increasing with average population age. Bone scatters more light (stress-whitens) during loading, immediately prior to failure, in a manner visually similar to polymer crazing. We wish to understand the stress-whitening process because of its possible effect on bone toughness. The goals of this investigation were a) to establish that stress-whitening is a property of the demineralized organic matrix of bone rather than only a property of mineralized tissue and that stress whitening within the demineralized bone is dependent upon both b) hydrogen bonding and, c) the orientation of loading. METHODS: Demineralized cortical bone specimens were loaded in tension to failure (0.08 strain/s). The effect of hydrogen bonding on mechanical properties and the stress-whitening process was probed by altering the Hansen's hydrogen bonding parameter (δh) of the immersing solution. RESULTS: Stress-whitening occurred in the demineralized bone. Stress-whitening was negatively correlated with δh (R(2)=0.81, p<0.0001). Stress-whitening was significantly lower (p<0.0001) in specimens loaded orthogonally compared to those loaded parallel to the long (strong) axis. CONCLUSION: The stress-whitening observed was consistent with increased Mie scattering. We suggest that the change in Mie scattering was due to collagen fibril dehydration driven by the externally applied stress. The presence of stress-whitening in demineralized bone suggests that this process may be a property of the collagenous matrix and hence may be present in other collagenous tissues rather than an emergent property of the bone composite.

Image segmentation using fuzzy region competition and spatial/frequency information.

This paper presents a multiphase fuzzy region competition model that takes into account spatial and frequency information for image segmentation. In the proposed energy functional, each region is represented by a fuzzy membership function and a data fidelity term that measures the conformity of spatial and frequency data within each region to (generalized) gaussian densities whose parameters are determined jointly with the segmentation process. Compared with the classical region competition model, our approach gives soft segmentation results via the fuzzy membership functions, and moreover, the use of frequency data provides additional region information that can improve the overall segmentation result. To efficiently solve the minimization of the energy functional, we adopt an alternate minimization procedure and make use of Chambolle's fast duality projection algorithm. We apply the proposed method to synthetic and natural textures as well as real-world natural images. Experimental results show that our proposed method has very promising segmentation performance compared with the current state-of-the-art approaches.

Texture classification using refined histogram.

In this correspondence, we propose a novel, efficient, and effective Refined Histogram (RH) for modeling the wavelet subband detail coefficients and present a new image signature based on the RH model for supervised texture classification. Our RH makes use of a step function with exponentially increasing intervals to model the histogram of detail coefficients, and the concatenation of the RH model parameters for all wavelet subbands forms the so-called RH signature. To justify the usefulness of the RH signature, we discuss and investigate some of its statistical properties. These properties would clarify the sufficiency of the signature to characterize the wavelet subband information. In addition, we shall also present an efficient RH signature extraction algorithm based on the coefficient-counting technique, which helps to speed up the overall classification system performance. We apply the RH signature to texture classification using the well-known databases. Experimental results show that our proposed RH signature in conjunction with the use of symmetrized Kullback-Leibler divergence gives a satisfactory classification performance compared with the current state-of-the-art methods.

Statistical wavelet subband characterization based on generalized gamma density and its application in texture retrieval.

The modeling of image data by a general parametric family of statistical distributions plays an important role in many applications. In this paper, we propose to adopt the three-parameter generalized Gamma density (GGammaD) for modeling wavelet detail subband histograms and for texture image retrieval. The advantage of GGammaD over the existing generalized Gaussian density (GGD) is that it provides more flexibility to control the shape of model which is critical for practical histogram-based applications. To measure the discrepancy between GGammaDs, we use the symmetrized Kullback-Leibler distance (SKLD) and derive a closed form for the SKLD between GGammaDs. Such a distance can be computed directly and effectively via the model parameters, making our proposed scheme particularly suitable for image retrieval systems with large image database. Experimental results on the well-known databases reveal the superior performance of our proposed method compared with the current existing approaches.

Altered motor control, posture and the Pilates method of exercise prescription.

The objectives of this study were to compare the effects of three different Pilates regimes on chronic, mild low back pain symptoms and to determine whether the efficiency of load transfer through the pelvis is improved by those exercises. A between subjects equivalent group experimental design was used. The independent variable was the type of exercise training (three groups) and the two-dependent variables were low back pain symptoms and load transfer through the pelvis. The outcome measures of the first-dependent variable were a comparison between modified Oswestry Disability Questionnaires (one of the standard pain instruments) completed pre- and post-program and frequency, intensity and duration of low back pain. The outcome measure of the second-dependent variable, efficiency of load transfer through the pelvis was the Stork test (one-legged standing test) in weight bearing. Although all groups experienced statistically significant reductions in frequency, intensity and duration of low back pain across the weeks of exercising, there were no significant differences between the groups relative to each other.

Statistical properties of bit-plane probability model and its application in supervised texture classification.

The modeling of wavelet subband histograms via the product Bernoulli distributions (PBD) has received a lot of interest and the PBD model has been applied successfully in texture image retrieval. In order to fully understand the usefulness and effectiveness of the PBD model and its associated signature, namely, the bit-plane probability (BP) signature on image processing applications, we discuss and investigate some of their statistical properties. These properties would help to clarify the sufficiency of the BP signature to characterize wavelet subbands, which, in turn, justifies its use in real time applications. We apply the BP signature on supervised texture classification problem and experimental results suggest that the weighted L(1)-norm (rather than the standard L (1)-norm) should be used for the BP signature. Comparative classification experiments show that our method outperforms the current state-of-the-art Generalized Gaussian Density approaches.

Point injection as an alternative acupuncture technique--an exploratory study of responses in healthy subjects.

INTRODUCTION: Point injection as a therapeutic technique is well documented, but its physiological effects have not been formally compared with traditional acupuncture. One aim of this study was to compare the effects of the two techniques at one acupuncture point, as a step towards understanding the mode of action of point injection and validating its clinical use. A second aim was to explore whether repeated point injection at the same site might provide a way of increasing the dose of stimulation, in the hope of identifying a dose response curve which could be an alternative strategy to placebo control in demonstrating the biological effects of acupuncture. METHODS: Sixty nine healthy subjects (age range 18-56 years, mean 29.9; 48 females) completed the study, which employed a counterbalanced experimental design with two stimulation sessions of LI4 approximately one week apart. One half of the participants received point injection first, and the other half received traditional acupuncture first. Baseline physiological data were recorded, then measurements were made before, during and after stimulation; each subject also reported needle sensation (de qi). The measures were heart rate, derived pressure rate product and mean arterial pressure. RESULTS: Although stronger sensations of de qi were reported with point injection, no significant differences were found for mean heart rate (HR), pressure rate product (PRP) and mean arterial pressure (MAP) before and after stimulation by the two techniques. No subject gender or age bias was encountered and previous exposure to acupuncture had no effect on outcome. Power spectral analysis of heart rate variability (HRV) made on data from a small subset (n=10) of this cohort also showed no significant differences in autonomic response. CONCLUSION: Point injection and traditional acupuncture seem to provoke similar physiological responses, although the greater needle sensation seen with point injection might indicate it could have more powerful clinical effects. Further studies of repeated point injection are necessary to indicate whether this technique may provide a method of increased strength of point stimulation, as an alternative to traditional needling in acupuncture research.

C. elegans SIN-3 and its associated HDAC corepressor complex act as mediators of male sensory ray development.

Mab21 gene family members are required for embryonic development and sensory organ formation in both invertebrates and vertebrates. However, their mechanistic role on differentiation is largely unexplored. We report here the isolation of SIN-3 as a MAB-21 interacting molecule. sin-3 is co-expressed with mab-21 in the ray structural cells and genetically interacts with mab-21 to control sensory organ development. Using pharmacological and RNAi approaches, we demonstrated that histone deacetylase and conserved SIN-3-associated components are required for ray patterning. Conserved physical interactions between these components were also observed, implicating the recruitment of HDAC complex by MAB-21/SIN-3 may occur to determine ray identity in males.

Evaluation of nutritional and inflammatory status of advanced colorectal cancer patients and its correlation with survival.

The purpose of this study was to evaluate novel inflammatory and nutritional prognostic factors in patients with advanced colorectal cancer (ACRC). All ACRC patients attending the clinic for palliative treatment were eligible for study. Demographics, including performance status (PS), C-reactive protein (CRP), albumin (Alb), Glasgow prognostic score (GPS), weight, weight history, body mass index (BMI), and nutritional status using the patient-generated subjective global assessment (PGSGA), were collected and correlated with survival. At a median follow-up of 29.8 mo, with a minimum follow-up of 15.7 mo, the median survival was 9.9 mo (0.8-21.8 mo). Fifteen (29%) patients were newly diagnosed (stage IV colorectal cancer), and 36 (71%) had received prior chemotherapy. Although the median BMI was 27 kg/m2 (range = 17-41 kg/m2), 28 of 50 (56%) were nutritionally at risk. In fact, 19 patients (38%) were critically in need of nutrition intervention (PGSGA score of > or =9). Thirty-three of 48 patients (69%) had an elevated CRP (>10 mg/l with a median of 21.1 mg/L), and 7 patients (15%) had both a CRP of >10 mg/l and hypoalbuminemia (< 35 g/l). A significant positive correlation was found between PGSGA score and CRP (P = 0.003; r = 0.430). Using univariate analysis, significantly worse survival was found for patients with poorer PS (P = 0.001), high GPS (P = 0.04), low Alb (P = 0.017), elevated serum alkaline phosphatase (SAP; P = 0.018), PGSGA score of > 9 (P = 0.001), and PGSGA group B/C (P = 0.02). Using the Cox proportional hazard model for multivariate survival analysis, type of treatment (hazard ratio, HR = 1.48; 95% confidence interval, CI = 1.11-1.79; P = 0.005), PS (HR = 2.37; 95% CI = 1.11-5.09; P = 0.026), GPS (HR = 2.27; 95% CI = 1.09-4.73; P = 0.028), and SAP (HR = 0.44; 95% CI = 0.18-1.07; P =0.069) remained significant predictors of survival. These preliminary data suggest that the type of treatment, PS, GPS, and SAP are important predictors of survival in ACRC.

Nutritional assessment in cancer: comparing the Mini-Nutritional Assessment (MNA) with the scored Patient-Generated Subjective Global Assessment (PGSGA).

The evaluation of nutritional status in cancer patients is often neglected in spite of the fact that poor nutritional status may adversely affect prognosis and treatment tolerance. In day-to-day oncology practice, a sensitive but simply applied nutritional assessment tool is needed to identify at-risk patients. Several tools exist; however, none has been universally accepted. The aim of this study was to compare two potential tools, the Mini-Nutritional Assessment (MNA) and the scored Patient Generated Subjective Global Assessment (PGSGA). The MNA is more simply applied and does not require a trained dietitian. The PGSGA has been previously validated in cancer patients. One hundred fifty-seven newly diagnosed cancer patients were assessed using both tools. Of these, 126 were reassessed at 4-6 wk, and 104 were reassessed at Weeks 8-12 after initial assessment. A significant negative correlation was found between the tools at all three time periods (at baseline r = -0.76; P < 0.001). Taking the PGSGA as the most accepted nutritional assessment tool, at baseline the MNA demonstrated a sensitivity of 97% and specificity of 54%. At 4-6 wk MNA sensitivity was 79% and specificity was 69%. At 8-12 wk MNA sensitivity was 93% and specificity was 82%. When comparing the tools in elderly patients alone (>65 yr), similar results were obtained. Both tools were able to correctly classify patients as malnourished, although the MNA lacks specificity. Therefore, the PGSGA should be the tool of choice for nutritional assessment in cancer patients.

Modelling the impact of population-based cytologic screening on cervical cancer incidence and mortality in Hong Kong: an age--period--cohort approach.

Cervical cancer incidence and mortality statistics in Hong Kong during 1972-2001 were examined to estimate the potential number of cancer cases that can be averted and years of life saved after the launch of an organised, population-based cytologic screening recall programme in 2004 with projections to 2016. Incidence rates under the status quo of opportunistic screening were projected by an age-period-cohort model, using maximum likelihood and Bayesian methods. Modelled rates were translated into numbers of cancer cases and deaths using mid-year population figures and age-period-specific mortality to incidence ratios. We applied International Agency for Research on Cancer risk reduction estimates for different screening strategies to these base case figures to estimate the number of incident cancers potentially averted and years of life saved attributable to organised screening incremental to the current status quo. The estimated numbers of cases projected to be preventable by the maximum likelihood (Bayesian) approach from 2002 to 2016 were 4226 (4176), 3778 (3728) and 2334 (2287) with organised screening every 1, 3 and 5 years, compared to haphazard screening currently. Correspondingly, 33,000 (32,800), 29,500 (29,300) and 18,200 (17,900) years of life could potentially be saved.

Thromboelastography, whole-blood haemostasis and recurrent miscarriage.

BACKGROUND: Some cases of recurrent miscarriage have a thrombotic basis. Thromboelastography is a rapid, reproducible test of whole-blood haemostasis. METHODS: Thromboelastography was performed in 494 consecutive, non-pregnant women (median age 35 years; range 21-48) with a history of miscarriages at <12 weeks gestation (median 4; range 3-12) and 55 parous women (median age 33 years; range 20-41) with no history of pregnancy loss. The prospective outcome of untreated pregnancies amongst 108 women with recurrent miscarriage was studied. RESULTS: The maximum clot amplitude (MA) (median 66.0 mm; range 48.0-76.0) was significantly higher and the rate of clot lysis (LY30) (median 2.5%; range 0.5-7.8) significantly lower amongst women with recurrent miscarriage compared with controls (MA 61.5 mm; range 50.0-67.0; P = 0.01; LY30 4.9%; range 2.9-9.7; P = 0.01). The pre-pregnancy MA was significantly higher amongst women who subsequently miscarried (median 66.0 mm; range 54.0-73.0) compared with those whose had a live birth (median 61.7 mm; 48.0-71.5; P < 0.01). A pre-pregnancy MA >or=64 mm has a sensitivity of 68% and specificity of 82% to predict miscarriage. CONCLUSIONS: Thromboelastography identifies a subgroup of women with recurrent miscarriage to be in a prothrombotic state outside of pregnancy. Women in such a state are at increased risk of miscarriage in future untreated pregnancies.

Ecological condition of central Australian arid-zone rivers.

Australian arid-zone rivers are known to be ecologically variable and go through "boom and bust" cycles based on highly variable and unpredictable flow regimes. They are facing increasing pressure from land and water resources development and, whilst they are considered to be still in relatively good condition, no studies have yet been carried out to verify this. Such baseline studies are crucial if we are to assess any ecological changes in response to development and management interventions. The ecological condition of four of these endorheic rivers (Georgina, Diamantina, Cooper-Thomson and Bulloo) flowing into the Lake Eyre and Bulloo Basins in central Australia was assessed using several criteria (level of human influence, habitat condition, water chemistry and aquatic macroinvertebrate composition). Using criteria based on the level of human influence, most of the sites were assessed to be relatively unimpacted (reference) condition. The most discernible and widespread impact was riparian and bank damage by stock access. However, the level of this impact was considered to be only moderate. Most aquatic macroinvertebrates found in the area are considered to be opportunistic and tolerant of a wide range of environmental conditions, but with their life histories known to be linked to flow conditions. Their trophic guild was dominated by collectors and predators. The AusRivAS modelled observed to expected values of macroinvertebrate composition indicated that there were differences in ecological condition between sites (e.g. different waterholes) and between times (e.g. seasons and years). Overall, 75% of sites were assessed to be good condition with the remainder being mildly impaired. Water chemistry of the sites was characterised by high spatial and temporal variability with low conductivity and alkaline pH, relatively high turbidity, total nitrogen and total phosphorus, and wide-ranging dissolved oxygen. Given the high variability in water quality and ecological condition within a catchment, there was little evidence of any overall difference in these factors between the catchments. However, given that the hydrology of each river system is distinctly different, one might expect some differences in ecological structure and function at finer scale. Periods of hydrological isolation (eg. to allow natural dryouts) as well as the maintenance of natural connectivity (eg. instream, overbank and floodplain wetting) are both necessary for the maintenance of ecological integrity of these systems.

Alteration of lysophosphatidylcholine content in low density lipoprotein after oxidative modification: relationship to endothelium dependent relaxation.

OBJECTIVE: The aim was to examine the formation of lipid peroxidation products and the alteration in phospholipid content in low density lipoprotein (LDL) after oxidative modification by CuSO4, and subsequently, to determine the ability of the modified LDL to impair endothelium dependent relaxation in rat aortic rings. METHODS: Blood samples were obtained from normal human volunteers. LDL was prepared by sequential ultracentrifugation and it was oxidatively modified in the presence of 5 microM CuSO4. Lipid peroxidation products (thiobarbituric acid reactive substances, TBARS), and alterations in electrophoretic mobility and phospholipid content were determined in normal (native) and oxidised LDL. Endothelium dependent relaxation was produced by acetylcholine (10(-8)-10(-5) M) in phenylephrine precontracted rat aortic rings. RESULTS: LDL incubated for 24 h with 5 microM CuSO4 at 20 degrees C and 37 degrees C with constant agitation displayed higher amounts of TBARS than the respective native LDL. While the amounts of TBARS in LDL modified at 20 degrees C and 37 degrees C were similar, the former condition resulted in statistically smaller changes of phospholipid contents. LDL with higher lysophosphatidylcholine content showed greater impairment of endothelium dependent relaxation in rat aortic rings than LDL with lower lysophosphatidylcholine content. CONCLUSIONS: The raised lysophosphatidylcholine level in oxidatively modified LDL was related to the ability of the LDL to impair endothelium dependent relaxation. However, lipid peroxidation products assessed by TBARS did not relate to the phospholipid changes in LDL and therefore cannot be used to predict the vascular effects of LDL after oxidative modification.