Immunochemical studies on human plasma lipoproteins

Some years ago, a series of human serum lipoproteins, distinguishable by their hydrated densities and lipid-protein ratios were recognized and isolated by ultracentrifugal techniques (1). Certain of these lipoproteins are invariably present in human serum and the concentrations of these and of others can be quantitatively correlated with disease (2). No difference in the lipoprotein distribution can be demonstrated between serum and plasma. The purpose of this investigation was to obtain information about the immunochemical specificity of some of the lipoproteins

Proteins involved in the Vroman effect during exposure of human blood plasma to glass and polyethylene

The amounts of fibrinogen adsorbed to glass from various human blood plasmas have been measured as a function of time. The plasmas were 11 single donor plasmas, pooled plasma, a single donor high molecular weight kininogen (HMWK)-deficient plasma and HMWK-deficient plasma, which had been reconstituted with HMWK. For adsorption times between 1 min and 1 h more fibrinogen adsorbed from HMWK-deficient plasma compared with the amounts of fibrinogen which adsorbed from the other plasmas. This result supports the conclusion of several authors that HMWK is involved in the displacement of fibrinogen, initially adsorbed from normal human plasma to glass. Glass surfaces, pre-exposed to solutions of plasma and subsequently exposed to 1:1 diluted plasma, gives rise to a relatively high adsorption of HMWK which is independent of the plasma concentration of the precoating solution. The results indicate that HMWK from 1:1 diluted plasma is involved in the displacement of proteins from glass surfaces which had been pre-exposed to solutions with a low plasma concentration. Experiments with polyethylene as a substrate reveal that high density lipoprotein (HDL) from 1:1 diluted plasma is involved in the displacement of proteins from polyethylene surfaces which had been pre-exposed to solutions with a low plasma concentration. Moreover, evidence is presented that substantial amounts of albumin and fibrinogen, adsorbed from 1:1000 diluted plasma to glass and polyethylene, are displaced from the surfaces of these materials by proteins from 1:1 diluted plasma different from HMWK and HDL

Expression of the plasma prekallikrein gene: utilization of multiple transcription start sites and alternative promoter regions

The plasma prekallikrein gene is expressed in many different human tissues at distinctly different levels and therefore tissue-specific control of the gene transcription is likely. In this study we demonstrate that transcription of the plasma prekallikrein gene can be initiated at multiple sites, for which at least four different promoters are utilized. A comparison of the genomic and mRNA sequences of mouse plasma prekallikrein revealed that the sequence segment that was formerly regarded as the first exon of the mouse plasma prekallikrein gene consists of three exons, with the first exon localized 14.2 kbp upstream of the translation start. For the rat and human plasma prekallikrein genes, in silico analysis suggested an analogous exon-intron organization. Determination of the transcription start sites showed that in both mouse and human, the proximal and distal regions could be utilized for transcription initiation; however, the proximal region is preferred. A deletion mutation analysis of the proximal promoter region using a 1.7-kbp segment revealed a strong activating region immediately upstream of the known mRNA, followed by both a modest repressor and an enhancer region

Plasma Soluble Human Elastin Fragments as an Intra-Aneurysmal Localized Biomarker for Ruptured Intracranial Aneurysm

Background—Fragmentation of the tunica media is a hallmark of intracranial aneurysm formation, often leading to aneurysmal progression and subsequent rupture. The objective of this study is to determine the plasma level of elastin fragments in the lumen of ruptured versus unruptured human intracranial aneurysms. Methods and Results—One hundred consecutive patients with/without ruptured saccular intracranial aneurysms undergoing endovascular coiling or stent-assisted coiling were recruited. Blood samples were collected from the lumen of intracranial aneurysm using a microcatheter. The tip of the microcatheter was placed inside the aneurysm’s sac in close proximity to the inner wall of the dome. Plasma levels of elastin fragments were measured using an ELISA-based method. Mean plasma level of soluble human elastin fragments was significantly greater in ruptured aneurysms when compared with nonruptured aneurysms (102.0±15.5 versus 39.3±9.6 ng/mL; P\u3c0.001). Mean plasma level of soluble human elastin fragments did not have significant correlation with age, sex, size, or aneurysm location. Conclusions—The present study revealed that a significantly higher concentration of soluble human elastin fragments in the lumen of ruptured intracranial aneurysms when compared with nonruptured ones. © 2018 The Authors

Detection of surface-adsorbed (lipo)proteins by means of a two-step enzyme-immunoassay: a study on the Vroman effect

In view of reports on the involvement of high-molecular-weight (HMW) kininogen and high-density lipoprotein (HDL) in the Vroman effect, we studied the adsorption of fibrinogen, HMW kininogen, HDL and several other proteins from pooled human plasma and congenitally HMW kininogen-deficient plasma onto glass and low-density polyethylene, both as a function of the plasma concentration and the contact time. Mixtures of purified (lipo)proteins were also included in the study. Protein adsorption was determined by means of a two-step enzyme-immunoassay. Our results support the hypothesis that HMW kininogen is involved in the displacement of fibrinogen, which is almost instantly adsorbed from normal plasma onto glass. On hydrophobic polymers like polyethylene, the low amounts of adsorbed fibrinogen and HMW kininogen from plasma and concentrated plasma solutions may be due to a preferential adsorption of HDL

Surface modification of hydrophobic polymers for improvement of endothelial cell-surface interactions

The aim of this study is to improve the interaction of endothelial cells with polymers used in vascular prostheses. Polytetrafluoroethylene (PTFE; Teflon) films were treated by means of nitrogen and oxygen plasmas. Depending on the plasma exposure time, modified PTFE surfaces showed water-contact angles of 15¿58° versus 96° for unmodified PTFE. Electron spectroscopy in chemical analysis (ESCA) measurements revealed incorporation of both nitrogenand oxygen-containing groups into the PTFE surfaces, dependent on the plasma composition and exposure time. In-vitro biological evaluation of unmodified and modified PTFE surfaces showed that human endothelial cells, seeded from 20% human serum-containing culture medium, adhered well on to modified PTFE surfaces, but not on to unmodified films. Adhesion of endothelial cells on to expanded PTFE graft material (Gore-Tex) was also stimulated by plasma treatment of this substrate. On plasma-treated expanded PTFE, the adhering endothelial cells formed a monolayer, which covered the textured surface. The latter observation is important in view of the hemocompatibility of vascular grafts seeded with endothelial cells before implantation

Endostatin concentration in plasma of healthy human volunteers

Background: Angiogenesis is involved in many cardiovascular and cancerous diseases, including atherosclerosis and is controlled by a fine balance between angiogenic and angiostatic mediators. Endostatin is one of the main angiostatic mediators, and inhibits angiogenesis and prevents progression of atherosclerosis. The available literature shows a broad range of concentrations in relatively small samples of healthy controls and is calculated by using different techniques. This study was aimed to determine the basal endostatin concentration in plasma of healthy volunteers, to fully understand its physiological role. Methods: Fifty healthy adult volunteers were recruited to the study. Participants were advised not to participate in any physical activity on the day before the blood sampling. The volunteers’ physical activity, height, weight, heart rate and blood pressure were recorded. The samples were analysed for plasma endostatin concentration, using ELISA. The participants were divided by gender and ethnic groups to calculate any difference. Results: Endostatin and other variables were normally distributed. Most of the participants had a moderate level of physical activity with no gender related difference (p=0.370). The mean value for plasma endostatin in all samples was 105±12 ng/ml with range of 81–132 ng/ml. For males, it was 107±13 ng/ml, while for females; 102±12 ng/ml. There were no significant gender or ethnicity related differences in endostatin concentration. Moreover, endostatin was not significantly related with any anthropometric and physical variable. Conclusion: This study gives endostatin levels in normal healthy people and show no gender and ethnicity related differences in endostatin levels. Endostatin was not related with any anthropometric and physical variable