Polyacrylamide Tube Gel Electrophoresis Research Articles

Comprehensive Lipoprotein Characterization Using Lipidomics Analysis of Human Plasma.

Lipoproteins are responsible for the transport of lipids and other nutrients in the circulation and therefore play an important role in lipid metabolism and dyslipidemia. They have also been linked to multiple metabolic disorders including cardiovascular disease, and thus understanding their lipid composition is of crucial importance. Characterization of lipoproteins is a challenging task due to their heterogeneity. In particular, their fractionation is often laborious and time-consuming, making large sets of clinical samples difficult to analyze. We developed and validated lipidomics analysis of lipoproteins including chylomicrons, very low-density, low-density, and high-density lipoproteins. Lipoproteins were first fractionated by polyacrylamide tube gel electrophoresis, and, after liquid-liquid extraction, lipids were analyzed by direct-infusion mass spectrometry. About 100 unique lipid species were detected with good reproducibility and reliability. In addition to their lipid composition, valuable information on the fatty acid composition of lipoproteins and lipids was obtained. The presented method offers in-depth analysis of the lipid as well as fatty acid composition of lipoproteins while allowing a good sample throughput. It is thus especially suited for studying lipid associated diseases in clinical cohorts.

Comparison of a direct enzymatic assay and polyacrylamide tube gel electrophoresis for measurement of small, dense low-density lipoprotein cholesterol.

Comparison of a direct enzymatic assay and polyacrylamide tube gel electrophoresis for measurement of small, dense low-density lipoprotein cholesterol.

Small-dense LDL/large-buoyant LDL ratio associates with the metabolic syndrome

ObjectiveHeterogeneous particles of intermediate-density lipoprotein (IDL) and low-density lipoprotein (LDL) vary in atherogenesis. We investigated the association between the metabolic syndrome (MetS) score and lipoprotein subclasses. Design and methodsA total of 260 outpatients were scored into six groups, based on their number of MetS components. Lipoprotein subclass determined by polyacrylamide tube gel electrophoresis separates IDL particles into three midbands (MID-A to C) and LDL into larger-buoyant (LDL1 and LDL2) and small-dense LDL (LDL3 to LDL6). ResultsMean concentrations of VLDL, MIDC, LDL2, and LDL3 to LDL6 positively correlated with increasing MetS score, but those of MIDA, LDL1 and HDL-C inversely correlated. LDL2 and LDL3 to LDL6 increased while MIDA and LDL1 decreased with increasing visceral fat, HOMA-IR, and triglycerides, with a reverse pattern for HDL-C. MIDB and MIDC were unchanged. By logistic regression, LDL1 and LDL3 to LDL6 significantly associates with the MetS score (odds ratio=0.957 and 1.077, respectively). The ratio of (LDL3 to LDL6)/LDL1 in the presence of HDL-C, showed the strongest association with MetS. ConclusionsRespective subpopulations of IDL and LDL particles can vary in their ability to identify MetS. Because of the most strongly associated with MetS, (LDL3 to LDL6)/LDL1 ratio is proposed as an excellent marker for evaluating lipid metabolic status in patient with MetS.

The effect of rosuvastatin on low-density lipoprotein subfractions in patients with impaired fasting glucose.

Prediabetes substantially increases cardiovascular risk. We examined the effect of rosuvastatin on the quantity and quality of low-density lipoprotein cholesterol (LDL-C) in patients with dyslipidemia having impaired fasting glucose (IFG) compared to normoglycemic patients with dyslipidemia. This was a prospective observational study including patients with dyslipidemia and IFG (IFG group, n = 49) matched with normoglycemic patients with dyslipidemia (control group, n = 64). Study participants, following dietary intervention, were prescribed rosuvastatin 10 or 20 mg/d to achieve LDL-C goals. Baseline as well as 24 weeks posttreatment changes in the serum lipid profile were evaluated. Moreover, analysis of the LDL subfraction profile was conducted using a polyacrylamide tube gel electrophoresis method. Similar effects were observed in lipid profile in both treatment groups. Patients with IFG experienced a greater decrease in the cholesterol concentration of small dense LDL particles (-65.7%, P < .001 vs baseline) compared to controls (-38.5%, P < .001 vs baseline; P = .018 vs patients with IFG). There was no significant difference in the changes of cholesterol concentration of large and buoyant LDL particles in the IFG group when compared to the control group. A greater increase in the mean LDL particle size (+1.5%, P < .001 vs baseline) was noted in the IFG group compared to the control group at 24 weeks (+0.4%, P = .028 vs baseline; P = .008 vs IFG group). Targeting dyslipidemia with rosuvastatin was associated with more favorable changes in the LDL subfraction profile in patients with IFG compared to normoglycemic ones.

The effect of rosuvastatin on low-density lipoprotein subfractions in patients with impaired fasting glucose

Background:Prediabetes substantially increases cardiovascular risk. We examined the effect of rosuvastatin on the quantity and quality of low-density lipoprotein cholesterol (LDL-C) in patients with dyslipidemia having impaired fasting glucose (IFG) compared to normoglycemic patients with dyslipidemia.Methods:This was a prospective observational study including patients with dyslipidemia and IFG (IFG group, n = 49) matched with normoglycemic patients with dyslipidemia (control group, n = 64). Study participants, following dietary intervention, were prescribed rosuvastatin 10 or 20 mg/d to achieve LDL-C goals. Baseline as well as 24 weeks posttreatment changes in the serum lipid profile were evaluated. Moreover, analysis of the LDL subfraction profile was conducted using a polyacrylamide tube gel electrophoresis method.Results:Similar effects were observed in lipid profile in both treatment groups. Patients with IFG experienced a greater decrease in the cholesterol concentration of small dense LDL particle...

Diabetes mellitus, but not small dense low-density lipoprotein, is predictive of cardiovascular disease: A Korean community-based prospective cohort study.

Small dense low-density lipoprotein (sdLDL) has been suggested to be a potential risk factor for cardiovascular diseases (CVD). We carried out a prospective nested case-control study in the Korean Health and Genome Study. Participants were men and women aged 40-69years who developed CVD (n=313), and were matched by age and sex to controls who remained free of CVD (n=313) during the 8-years follow-up period (from 2001 to 2009). LDL subfractions were analyzed in frozen samples collected from the 626 participants using polyacrylamide tube gel electrophoresis. Patients with CVD had a significantly higher glycated hemoglobin level compared with the controls (5.72 vs 5.56). The proportion of patients with diabetes mellitus (DM) was higher in those who developed CVD during follow up (8.0% vs 1.9%). The frequency of CVD according to each tertile of LDL particle size and the number of metabolic syndrome components did not differ significantly. In the multivariate analysis, DM (odds ratio 4.244, 95% confidence interval 1.693-10.640, P=0.002) was the only independent predictive factor of CVD. LDL particle size was not associated with the risk for future CVD. Small dense LDL might not be a significant predictor of CVD in this Korean community-based prospective cohort study.

Higher levels of small dense low‐density lipoprotein (LDL) are associated with cardiac autonomic neuropathy in patients with Type 2 diabetes

To investigate the relationship between small dense LDL cholesterol and cardiac autonomic neuropathy among patients with Type 2 diabetes. A total of 175 patients who had not taken lipid-lowering agents previously were enrolled consecutively in this study. Small dense LDL cholesterol level was measured using polyacrylamide tube gel electrophoresis, which fractionates LDL cholesterol into seven components according to particle size and charge. We analysed the mean LDL cholesterol particle size and the proportion of small dense LDL cholesterol. The mean (± sd) patient age was 56 (± 14) years, the mean (± sd) duration of diabetes was 10.3 (± 8.3) years, the mean (± sd) proportion of small dense LDL cholesterol was 21.3 (± 17.6)% and the mean (± sd) LDL cholesterol size was 26.33 (± 0.8) nm. Men with cardiac autonomic neuropathy had a longer duration of diabetes compared with those without cardiac autonomic neuropathy. Women with cardiac autonomic neuropathy had a larger waist circumference, higher plasma triglyceride levels, smaller mean (± sd) LDL cholesterol size [26.8 (± 4.3) nm vs 26.4 (± 6.9) nm; P < 0.01] and larger mean (± sd) proportion of small dense LDL cholesterol [10.1 (± 9.9)% vs 19.1 (± 16.8)%; P < 0.01] compared with those without cardiac autonomic neuropathy. After adjusting for other confounding risk factors, the triglyceride/ HDL cholesterol ratio (odds ratio = 1.698, 95% CI: 1.07-2.69; P = 0.025) and mean LDL cholesterol size (odds ratio = 0.873, 95% CI: 0.77-0.99; P = 0.038) remained as independent risk factors for cardiac autonomic neuropathy in women. A more atherogenic lipid profile such as the triglyceride: HDL cholesterol ratio and a smaller mean LDL cholesterol particle size were related to the prevalence of cardiac autonomic neuropathy in women with Type 2 diabetes.

Comparability of two different polyacrylamide gel electrophoresis methods for the classification of LDL pattern type

BackgroundThe measurement of small dense low-density lipoprotein (sdLDL) particles is relevant when assessing cardiovascular risk. However, there is as yet no referenced method for the determination of LDL subfractions or a standardized comparison of the methods currently available.Therefore, the aim of this study was to compare the pattern of LDL particles measured by polyacrylamide tube gel electrophoresis (PTGE) and polyacrylamide gradient gel electrophoresis (PGGE) and to correlate the results with triglyceride concentration. Materials and methodsSerum samples were collected from 177 patients. Lipid profile and LDL particle size were assessed using PTGE and PGGE. ResultsPearson correlation and kappa index revealed a very good agreement between the methods. There was 81.3% concordance for classification of sdLDL particles and 97.2% concordance for classification of large LDL when PTGE and PGGE were compared. LDL size correlated with triglyceride in subjects with triglyceride levels >116mg/dl, pointing to a high CAD risk, as reflected by their higher prevalence of pattern B. ConclusionsPTGE correlates favourably and is in very good agreement with PGGE. The determination of LDL particle size may be an appropriate analytical procedure to estimate CAD risk in patients with high triglyceride levels.

Smaller Mean LDL Particle Size and Higher Proportion of Small Dense LDL in Korean Type 2 Diabetic Patients

BackgroundSmall dense low density lipoprotein (sdLDL) has recently emerged as an important risk factor of coronary heart disease.MethodsThe mean LDL particle size was measured in 203 patients with type 2 diabetes mellitus (T2DM) and 212 matched subjects without diabetes using polyacrylamide tube gel electrophoresis. Major vascular complications were defined as stroke, angiographically-documented coronary artery disease or a myocardial infarction. Peripheral vascular stenosis, carotid artery stenosis (≥50% in diameter) or carotid artery plaque were considered minor vascular complications. Overall vascular complications included both major and minor vascular complications.ResultsDiabetic patients had significantly smaller mean-LDL particle size (26.32 nm vs. 26.49 nm) and a higher percentage of sdLDL to total LDL compared to those of subjects without diabetes (21.39% vs. 6.34%). The independent predictors of sdLDL in this study were serum triglyceride level and body mass index (odds ratio [OR], 1.020 with P<0.001 and OR 1.152 with P<0.027, respectively). However, no significant correlations were found between sdLDL and major vascular complications (P=0.342), minor vascular complications (P=0.573) or overall vascular complications (P=0.262) in diabetic subjects.ConclusionDiabetic patients had a smaller mean-LDL particle size and higher proportion of sdLDL compared to those of subjects without diabetes. Obese diabetic patients with hypertriglyceridemia have an increased risk for atherogenic small dense LDL. However, we could not verify an association between LDL particle size and vascular complications in this study.

LDL Species Heterogeneity in the Atherogenic Dyslipidemia of Polycystic Ovary Syndrome

One of the important risk factors for coronary heart disease is dyslipidemia. Several lipid abnormalities have been studied in patients with polycystic ovary syndrome (PCOS), but the relationship between PCOS and low-density lipoprotein (LDL) subclass pattern is not clear. A case-control study was designed to look into lipid differences, and LDL size was analyzed by a newly developed polyacrylamide tube gel electrophoresis method. Results indicated that only PCOS status and serum triglyceride levels were independently associated with LDL particle size. The apolipoprotein (Apo)A-I level was higher in PCOS patients with small dense LDL (sdLDL). PCOS seems to result in smaller LDL particle size and higher ApoA-I levels independent of triglyceride levels. After adjusting for triglyceride levels, other traits of insulin resistance syndrome (IRS) were not associated with LDL size phenotype, suggesting that the IRS-related sdLDL is linked most strongly to alterations in triglyceride levels.

Comparison of Low-Density Lipoprotein Size by Polyacrylamide Tube Gel Electrophoresis and Polyacrylamide Gradient Gel Electrophoresis

We evaluated a low-density lipoprotein (LDL) subfraction separation method using polyacrylamide tube gel electrophoresis (PTGE) and compared it with the reference method, polyacrylamide gradient gel electrophoresis (PGGE-REF). Excellent intra-assay and interassay coefficients of variation were obtained (<4%) for PTGE. For 102 subjects, LDL subclasses correlated most significantly with triglyceride (TG) level, high-density lipoprotein (HDL) cholesterol level, total cholesterol/HDL cholesterol ratio, and non-HDL cholesterol level (P < .05). The distribution of large LDL (76%) was predominant for subjects with low TG levels (<150 mg/dL [1.69 mmol/L]), while distribution of small LDL (79%) was predominant for subjects with high TG levels (>200 mg/dL [2.26 mmol/L]). Excellent agreement between the methods was observed (weighted kappa = 0.78). Of 51 samples classified as small, dense LDL by PGGE-REF, none were misclassified as large LDL and 4 as intermediate LDL by PTGE (92% concordance); of 44 samples classified as large LDL by PGGE-REF, 3 were misclassified as small and 7 as intermediate by PTGE (77% concordance). The PTGE method is precise and compares favorably with PGGE-REF. It has the advantage of being simple, less expensive, and more suitable for use in the clinical laboratory.

Aflatoxin-induced alterations in Glycine max, cv. 'Essex' root cell membrane protein content.

Aflatoxins (AFTs) are hepatocarcinogens, mutagens, teratogens and toxins. Isolates of AFTs-producing strains of Aspergillus flavus can grow upon both autoclaved soybeans and to a lesser extent field-grown beans. Besides inhibiting the elongation of excised, in vitro cultured soybean roots, the AFTs can impair the roots' ability to remove [14C]-leucine from a culture medium and to incorporate the amino acid into acid-insoluble, cytoplasmic protein. In this connection, exogenous AFTs once taken-up and compartmentalized by the excised roots can reduce the acid-insoluble protein content of what appears to be a non-enriched plasmalemma fraction. Here, we report a combined biochemical and microscopical attempt to determine whether the protein reduction occurs throughout the excised, in vitro-cultured root and whether the plasmalemma proteins which are affected by AFTs can be both solubilized and characterized. Histochemistry of Carnoy-fixed roots revealed a reduction in Ninhydrin-Schiff-stainability throughout the AFTs-treated root. Transmission electron microscopy of 80 000 X g pellets derived from homogenates of both non-treated (NT) and treated (T) roots provided further evidence to our previously reported marker enzyme analyses for the occurrence of the plasmalemma in the 80 000 X g pellet. Treatment of the latter with the Laemmli SDS procedure released greater than 85% of the protein associated with the pellets obtained from homogenates of either NT or T roots. Gel permeation chromatography on Biogel-100 of released proteins from 80 000 X g pellets of both NT and T roots yielded both void volume and retarded peaks. Both the amplitude and the quantities of protein recovered within the void volume peak were less within the void volume of the t than the NT root. Polyacrylamide tube gel electrophoresis of G-100 void volume peaks of chromatographed, SDS-released proteins from the pellets revealed quantitative but not qualitative differences in Coomassie Blue-gel staining patterns between T and NT roots. These results suggest that the SDS methods which we employed could solubilize the 80 000 X g pellet proteins but that combined gel permeation chromatography and tube gel electrophoresis were not sensitive enough to reveal whether AFTs could alter the types of proteins associated with the 80 000 X g pellet (purported plasmalemma).

Location of chromosomal control of ribulose bisphosphate carboxylase amounts in wheat

The central role of ribulose bisphosphate carboxylase (RuBPCase) in the photosynthetic process makes genetic manipulation of amounts of this enzyme particularly desirable, and the location of its genetic control of fundamental importance. In order to determine this location in wheat (Triticum aestivum) RuBPCase amounts per cell were measured in aneuploids of the cultivar Chinese Spring using colorimetric quantification following polyacrylamide tube gel electrophoresis. In this way homoeologous chromosome group 4 was identified as the site of major control of RuBPCase levels in leaves of breadwheat.

4 S RNA in regenerating optic axons of goldfish

Previous experiments have demonstrated that 4 S RNA is transported axonally during the reconnection period of optic nerve regeneration in goldfish. The present experiments were performed to determine whether 4 S RNA is transported axonally during later, maturational stages of nerve regeneration and to examine some of the characteristics of 4 S RNA in regenerating axons. [3H]Uridine was injected into both eyes of fish 18 days (near the time of reconnection) after bilateral optic nerve crush and the fish were sacrificed at various times up to 180 days after injection. [2H]RNA was isolated by phenol extraction and ethanol precipitation from 24 pooled tecta and fractionated by SDS-polyacrylamide tube gel electrophoresis. Data from these experiments showed that 70% of the [3H]RNA is present as 4 S RNA 12 days after injection, and 60 days after injection, this value is still approximately 50%. When nerves were cut 36 days after injection (54 days post-crush) and allowed to degenerate for 6 days before determining tectal [3H]RNA, the majority of the 4 S[3H]RNA was lost from the tectum. This indicates that up to 36 days after injection, 4 S [3H]RNA remains within regenerating axons and that it is unlikely that significant amounts of axonally transported 4 S RNA are transferred out of the axon to surrounding cells. In other experiments, the time of sacrifice after injection was held constant and the time of injection after nerve crush was varied. Analysis of tectal [3H]RNA showed that the major period of axonal transport of 4 S [3H]RNA was in early stages of regeneration at 24 and 36 days after nerve crush and that the amount of 4 S [3H]RNA which is transported axonally decreased at later time points. Calculations of the amount of axonal 4 S [3H]RNA versus what is synthesized in periaxonal cells gave results suggesting that 4 S RNA in regeneration axons turns over relatively slowly when compared with 4 S RNA in tectal cells.

Characterization of a viroid associated with avocado sunblotch disease

A viroid has been purified from avocado leaves infected by sunblotch disease and designated the avocado sunblotch viroid. It is a covalently closed circular RNA molecule with a molecular weight lower than that of chrysanthemum stunt viroid and citrus exocortis viroid while hybridization analysis with 32P-labeled complementary DNA indicated that it is a single RNA species. It could be detected as a stainable RNA band on polyacrylamide tube gel electrophoresis of partially purified extracts of only two of four avocado isolates with positive symptoms of sunblotch disease. However, the viroid was detected in all four isolates by hybridization analysis with 32P-complementary DNA; this procedure has potential use for the rapid indexing of sunblotch disease since the viroid was not present in an isolate of healthy avocado. It has yet to be shown that the viroid is the causative agent of sunblotch disease.

The light-harvesting chlorophyll [formula omitted] complex from barley thylakoid membranes. Polypeptide composition and characterization of an oligomer

Electrophoretic analysis by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis showed that the light-harvesting chlorophyll a b - protein complex of barley thylakoids contains only one polypeptide of apparent molecular weight 26 000. The barley mutant, deficient in chlorophyll b and this light-harvesting complex, lacks this polypeptide. The addition of a nonionic detergent, Triton X-100, to the sodium dodecyl solubilization buffer prior to SDS polyacrylamide tube gel electrophoresis, allowed separation of a relatively stable complex, characterized as an oligomeric form of the light-harvesting complex. The oligomer also contained a polypeptide with an apparent molecular weight of 26 000. The absorption and fluorescence spectral properties of the oligomer are similar to those of the monomer. It is suggested that the oligomer of the light-harvesting chlorophyll a b - protein is closer to the in vivo form rather than the monomer.