Role Of Plasma Research Articles

Influence of polymorphonuclear leukocytes and plasma on coronary vasomotion after ischemia

Background. The role of plasma and neutrophils in endothelial dysfunction following myocardial ischemia was investigated. Methods. Isolated rabbit hearts were perfused at constant pressure with a modified Krebs-Henseleit solution. After a 30-minute global ischemia the hearts were perfused at the onset of reperfusion for 10 minutes with either NaCl (group I, n = 6), autologous plasma alone (group II, n = 5), autologous polymorphonuclear leukocytes alone (PMN, group III, n = 6), or PMN and plasma in combination (group IV, n = 5). Before and after ischemia the effects of intracoronary endothelial dependent and independent vasodilation by acetylcholine (1 × 10 −7mol/L) and glycerol trinitrate (1 × 10 −6mol/L) were investigated. Results. A similar increase in coronary flow was induced in groups I, II, and III by acetylcholine and glycerol trinitrate before and after ischemia. In contrast, in group IV the endothelial dependent vasodilation was significantly depressed ( p< 0.05). In groups II and IV a moderate but significant reduction in the recovery of the left ventricular pressure was observed after ischemia and reperfusion. Conclusions. These results suggest that after myocardial ischemia, plasma is required for neutrophil-mediated endothelial dysfunction.

Determinants of plasma coenzyme Q 10 in humans

In the present study, we assessed the strongest determinants of plasma coenzyme Q 10 (Q 10) in 518 men and women (aged 45–70 years) with a stepwise multivariate regression model. Male gender ( P<0.001), serum cholesterol ( P<0.001), serum γ-glutamyltransferase ( P<0.001), serum triglycerides ( P<0.001), age ( P=0.017) and 4-day alcohol consumption ( P=0.03) were the most important factors which were directly associated with plasma Q 10. The intensity of conditioning exercise ( P=0.03) and use of statins ( P<0.05) showed an inverse association with plasma Q 10. None of the assessed nutrients increased plasma Q 10 levels significantly. Our results suggest that many confounding factors, in addition to serum cholesterol and triglycerides, should be taken into account when the role of plasma Q 10 is examined in epidemiological research.

Role of plasma and urinary endothelin-1 in early diabetic and hypertensive nephropathy

To evaluate the role of circulating and renal endothelin-1 (ET-1) in early diabetic nephropathy, plasma ET-1 levels and urinary ET-1 excretion were evaluated in lean, normotensive patients affected by non–insulin-dependent diabetes (NIDDM) either with (n = 9, NIDDM+) or without microalbuminuria (n = 18, NIDDM−); in never-treated, lean, essential hypertensive patients with (n = 12, EH+) or without microalbuminuria (n = 10, EH−); and in healthy volunteers (n = 12). Results showed higher plasma ET-1 levels in NIDDM+ (1.97 ± 0.58 pg/mL) than in NIDDM− (1.59 ± 0.14 pg/mL, P = .013), EH+ (1.40 ± 0.21 pg/mL, P = .005), EH− (0.91 ± 0.19 pg/mL, P < .0001), and controls (0.60 ± 0.10 pg/mL, P < .0001). The circulating ET-1 concentration was also higher in EH+ than EH− and controls ( P < .0001). Urinary ET-1 excretion did not differ ( P = .387, NS) between NIDDM+ (48.5 ± 20.1 pg/min) and NIDDM− (40.9 ± 21.6 pg/min), but was significantly reduced ( P < .0001) in both groups compared with controls (70.0 ± 15.5 pg/min). Similar findings were observed in hypertensive subgroups. No correlations were found between urinary ET-1 and other variables, including plasma ET-1 levels, in all groups. In conclusion, NIDDM+ is accompanied by a significant increase in plasma ET-1 levels. A significant elevation of circulating ET-1 concentration was evident also in NIDDM−, suggesting that early abnormalities of ET-1 production might precede the microalbuminuric phase of diabetes-related renal damage.

Alpha1-microglobulin is found both in blood and in most tissues.

In this study we demonstrate that, in addition to blood, alpha1-microglobulin (alpha1m) is present in most tissues, including liver, heart, eye, kidney, lung, pancreas, and skeletal muscle. Western blotting of perfused and homogenized rat tissue supernatants revealed alpha1m in its free, monomeric form and in high molecular weight forms, corresponding to the complexes fibronectin-alpha1m and alpha1-inhibitor-3-alpha1m, which have previously been identified in plasma. The liver also contained a series of alpha1m isoforms with apparent molecular masses between 40 and 50 kD. These bands did not react with anti-inter-alpha-inhibitor antibodies, indicating that they do not represent the alpha1m-bikunin precursor protein. Similarly, the heart contained a 45-kD alpha1m band and the kidney a 50-kD alpha1m band. None of these alpha1m isoforms was present in plasma. Immunohistochemical analysis of human tissue demonstrated granular intracellular labeling of alpha1m in hepatocytes and in the proximal epithelial cells of the kidney. In addition, alpha1m immunoreactivity was detected in the interstitial connective tissue of heart and lung and in the adventitia of blood vessels as well as on cell surfaces of cardiocytes. alpha1m mRNA was found in the liver and pancreas by polymerase chain reaction, suggesting that the protein found in other tissues is transported via the bloodstream from the production sites in liver and pancreas. The results of this study indicate that in addition to its role in plasma, alpha1m may have important functions in the interstitium of several tissues. (J Histochem Cytochem 46:887-893, 1998)

Linear theory of a plasma loaded, helix type, slow wave amplifier

The linear theory of a plasma loaded helix type traveling wave tube amplifier (TWTA) is considered. The role of plasma on the gain and the degree of concentration of the high frequency fields in the region of the plasma is studied. Strong gain enhancements are observed for frequencies in which hybrid plasma-slow waves are formed. Use of plasma allows for strong interaction even if the beam is displaced from the immediate vicinity of the structure. This latter effect could allow for the development of higher power amplifiers with larger cross-sectional areas.

Role of Plasma and Extracellular Matrix Proteins in the Physiopathology of Foreign Body Infections

Foreign body implants are highly susceptible to microorganism infection. The infectious agents may be of low pathogenicity (such as S. epidermidis) or involve more virulent strains (such as S. aureus). The common denominator for the three main elements that play a role in the physiopathology of such infections (bacteria, neutrophils, and different biomaterials) are host proteins deposited over the surface of the devices immediately after their implantation. These proteins modulate that host cells response but can also promote Staphylococcus adhesion to the biomaterial. Neutrophils and other cells such as fibroblasts adhere to several extracellular matrix proteins such as fibronectin, fibrinogen, collagen, vitronectin, via specific cell surface receptor. The evolution of the technology and the increasing numbers of long-term artificial implants require a better understanding of fundamental mechanisms of foreign body infections to reduce their incidence and optimize their treatment.

Sodium dependent ion transporters in trout gills

Biochemical procedures developed to isolate plasma membranes from the branchial epithelium of rainbow trout (Oncorhynchus mykiss) yield membrane fractions that are specifically enriched in the plasma membrane marker enzyme Na+/K+-ATPase. As the bulk of the branchial Na+/K+-ATPase is assumed to be confined to the mitochondria-rich chloride cells, such membrane preparations must contain the essence of the enzymatic machinery of the chloride cells. Basal Na+ activity in branchial (chloride) cells is around 10 millimolar and, accordingly, we find a Km for Na+ of the Na+/K+-ATPase of 13 millimolar, indicating that the enzyme may be regulated by changes in cytosolic sodium. The Na+-gradient across the serosal plasma membrane created by this pump provides energy for 3Na+/Ca2+-exchange and bumetanide-sensitive Na+/K+/2Cl--cotransport. Here we further postulate the presence of a Na+/Cl--cotransporter, indicated by thiazide-sensitive, bumetanide-insensitive transport of Na+ and Cl-; this cotransporter activity awaits the characterization of its kinetics. The Na+/Ca2+-exchanger has kinetic characteristics compatible with a regulatory role of cytosolic Na+ in the activity of this carrier. Both Na+/Ca2+-exchange and Ca2+-ATPase activity may contribute to transport of Ca2+, the former having lower affinity for calcium but a higher capacity than the latter carrier. The Na+/K+/2Cl--cotransporter has kinetics that favor a regulatory role for plasma K+ in the activity of this carrier. Seawater adaptation leads to increased activity of cotransporter molecules in the plasma membrane fractions (the activity increases relative to that of the Na+/K+-ATPase) and this may reflect a function in Cl--extrusion performed by the chloride cells in a seawater environment. A function for the cotransporter in the gills of freshwater fish may be the regulation of cell volume.

Role of Urinary Arginine Vasopressin in the Sodium Excretion in Patients With Chronic Renal Failure

Patients with chronic renal failure show almost equal levels of sodium excreted in the urine as healthy subjects through an increase of the fractional excretion sodium (FENa). The mechanisms of this adaptation, however, are unknown. Recently, urinary arginine vasopressin (AVP) has been shown to inhibit the antidiuretic action of plasma AVP in the collecting ducts of rabbits and rats. In this article, the roles of plasma and urinary AVP are examined with other hormones in the sodium excretion of 57 patients with chronic renal disease. The fractional excretion of AVP, plasma atrial natriuretic peptide (ANP) and endothelin-1 (ET-1), urinary ET-1, and FEET-1 correlated with the decrease of creatinine clearance (Ccr). Multiple and stepwise regression analyses showed that FEAVP is the major dependent determinant for FENa (adjusted r2 = 0.78). These results suggest that the increase of AVP excretion per remaining nephron could be a cause of the increase of FENa in patients with renal failure. Although plasma AVP works as an antidiuretic hormone, urinary AVP serves as an intrinsic diuretic, especially in patients with chronic renal failure. Patients with chronic renal failure show almost equal levels of sodium excreted in the urine as healthy subjects through an increase of the fractional excretion sodium (FENa). The mechanisms of this adaptation, however, are unknown. Recently, urinary arginine vasopressin (AVP) has been shown to inhibit the antidiuretic action of plasma AVP in the collecting ducts of rabbits and rats. In this article, the roles of plasma and urinary AVP are examined with other hormones in the sodium excretion of 57 patients with chronic renal disease. The fractional excretion of AVP, plasma atrial natriuretic peptide (ANP) and endothelin-1 (ET-1), urinary ET-1, and FEET-1 correlated with the decrease of creatinine clearance (Ccr). Multiple and stepwise regression analyses showed that FEAVP is the major dependent determinant for FENa (adjusted r2 = 0.78). These results suggest that the increase of AVP excretion per remaining nephron could be a cause of the increase of FENa in patients with renal failure. Although plasma AVP works as an antidiuretic hormone, urinary AVP serves as an intrinsic diuretic, especially in patients with chronic renal failure.

Role of urinary arginine vasopressin in the sodium excretion in patients with chronic renal failure.

Patients with chronic renal failure show almost equal levels of sodium excreted in the urine as healthy subjects through an increase of the fractional excretion sodium (FE(Na)). The mechanisms of this adaptation, however, are unknown. Recently, urinary arginine vasopressin (AVP) has been shown to inhibit the antidiuretic action of plasma AVP in the collecting ducts of rabbits and rats. In this article, the roles of plasma and urinary AVP are examined with other hormones in the sodium excretion of 57 patients with chronic renal disease. The fractional excretion of AVP, plasma atrial natriuretic peptide (ANP) and endothelin-1 (ET-1), urinary ET-1, and FE(ET-1) correlated with the decrease of creatinine clearance (Ccr). Multiple and stepwise regression analyses showed that FE(AVP) is the major dependent determinant for FE(Na) (adjusted r2 = 0.78). These results suggest that the increase of AVP excretion per remaining nephron could be a cause of the increase of FE(Na) in patients with renal failure. Although plasma AVP works as an antidiuretic hormone, urinary AVP serves as an intrinsic diuretic, especially in patients with chronic renal failure.

Cytokine Production by Human Peripheral Blood Mononuclear Cells Stimulated by aPseudomonas AeruginosaCulture Filtrate: Role of Plasma and Polymyxin B

The lack of consensus regarding the significance of transmembrane passage of bacterial products across hemodialysis membranes can be related to several methodological differences in the various studies, including the choice of circulating fluid in the blood compartment of the model, nature and concentration of the bacterial products employed to challenge the dialysate compartment and whether cytokine production by PMBC or the limulus amebocyte lysate (LAL) assay was used as the index of transfer and the cytokine used as the read-out. In this study, we examined the production of interleukin-1 alpha (IL-1 alpha), interleukin-1 receptor antagonist (IL-1Ra) and interleukin-8 (IL-8) by peripheral blood mononuclear cells (PBMC) incubated with a Pseudomonas aeruginosa culture filtrate. Further, the effects of 10% autologous human plasma and Polymyxin B sulfate (PmB) on cytokine production by PBMC were also characterized. The results of our study indicate that the Ps. aeruginosa culture filtrate had both PmB suppressible and PmB non-suppressible components and that the addition of 10% human plasma significantly enhanced cytokine production by both PmB suppressible and PmB non-suppressible components. The enhancing effect of plasma was most evident at low concentrations of the filtrate. The inhibitory effect of PmB was most evident in samples cultured in the presence of 10% plasma. There was a direct correlation between the production of IL-1 alpha and IL-1Ra suggesting that both pro-inflammatory cytokines and cytokine-specific inhibitory proteins are concurrently produced. There results have direct relevance to selection of study conditions for in vitro models used to study the transmembrane passage of bacterial products across hemodialysis membranes.

The role of plasma in the disturbance of basal cytosolic calcium in platelets from patients with cirrhosis: [formula omitted]. Liver Research Laboratories, Department of Medicine, Royal Infirmary, Lauriston Place, Edinburgh. Scotland

The role of plasma in the disturbance of basal cytosolic calcium in platelets from patients with cirrhosis: [formula omitted]. Liver Research Laboratories, Department of Medicine, Royal Infirmary, Lauriston Place, Edinburgh. Scotland

An investigation on the role of plasma and serum opsonins on the evternalization of biodegradable poly(D,L-lactic acid) nanoparticles by human monocytes

We demonstrate here that polyethylene glycol (PEG) 6,000 protects biodegradable poly(D,L-lactic acid) nanoparticles (PLA NP) from extensive uptake by monocytes in plasma. These results are in agreement with those previously obtained with PEG 20,000 which reduced the uptake of PLA NP by human monocytes in phosphate buffered saline and plasma, and prolonged the NP circulation time in vivo. The coating efficiency of PEG 6,000 and 20,000 was substantially decreased in serum. The difference between the uptake of plain and coated NP clearly reappeared for PEG 20,000-coated NP in heat inactivated serum and in IgG-depleted serum. We suggest that typical plasma proteins, heat labile serum proteins ( e.g. complement components) and IgG are involved in the opsonization of plain and coated PLA NP. Other proteins previously found to adsorb onto these NP, namely albumin and apolipoprotein E, did not appear to directly influence the uptake process.

The Role of Plasma from Platelet Concentrates in Transfusion Reactions

Comment: Febrile nonhemolytic transfusion reactions occur in 5–30% of platelet transfusions. This carefully conducted study indicates that a significant proportion of these reactions may be related to the plasma supernatant in the platelet concentrates. It suggests that toxic soluble products, such as interleukins, may be produced by white cells during storage and released into the supernatant. These observations would explain why removing leukocytes from the product before transfusion is not effective in preventing reactions in all patients. However, depleting platelet concentrates before storage may be effective in preventing these reactions. Larger scale studies would be needed to demonstrate wheuier this would be efficacious and cost-effective. It should be noted that even this type of treatment will not prevent all reactions. Several patients in this study reacted only to the cellular component of the platelet product, suggesting that there are other mechanisms for reaction in some patients. The investigators in this study found that interleukin-1β and interleukin-6 levels in the plasma supernatant correlated with severity of reactions. However, these were the only cytokines that were assayed. Multiple other bioreactive substances could in fact be involved in these reactions. Further studies involving specific blockers of cytokines would be necessary to demonstrate which exact substances are responsible for these reactions.

The role of plasma coating on the permeation of cytokine-inducing substances through dialyser membranes

We studied the effects of coating of dialyser membranes with plasma proteins on the permeation of bacteria-derived cytokine-inducing substances (CIS). An in vitro dialysis circuit using polysulphone (PS) or modified cellulose triacetate (mCT) dialysers was used. Precoating of the dialysers was performed by recirculation of 10% normal human plasma for 30 min in the blood compartment and subsequent rinse with pyrogen-free saline. Samples from the blood compartment were tested for induction of interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta) and tumour necrosis factor (TNF alpha) at various time points after challenging the dialysate with sterile culture supernatants from Pseudomonas aeruginosa. Contamination of the dialysate resulted in the appearance of CIS in the blood compartment of both polysuphone modified cellulose triacetate (IL-1 alpha: PS, time 0: 81 +/- 11 pg/ml, time 60 min: 4747 +/- 1822 pg/ml, P < 0.05; mCT, time 0: 235 +/- 141 pg/ml, time 60 min: 1632 +/- 531 pg/ml, P < 0.05). The plasma protein layer reduced the penetration of CIS significantly only for polysulphone (IL-1 alpha: PS, time 60: 4747 +/- 1822 versus 880 +/- 525 pg/ml, P < 0.05; modified cellulose triacetate, time 60 min: 1632 +/- 531 pg/ml versus 930 +/- 326 pg/ml). Samples from the blood compartment contained < 6 pg/ml LAL-reactive material at all time points. We conclude that plasma coating of polysulphone dialysers reduces the permeability for CIS derived from Pseudomonas, either by reducing the effective pore size or by adsorption of proteins that bind CIS.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma prorenin as an early marker of nephropathy in diabetic (IDDM) adolescents

We studied a group of 50 adolescents, average age 16 years, with diagnosed IDDM present for about seven years. Twenty-five had microalbuminuria (MA) averaging 111.0 +/- 34.0 (SEM) micrograms/min albumin excretion rate versus 6.7 +/- 7.4 micrograms/min in the 25 without MA. In other respects, such as sex ratio, age, body mass index, duration of IDDM, hemoglobin A1c, and normotensive systolic, diastolic and mean blood pressures (BP), these subgroups were closely matched. We compared them with a control group of 39 normotensive adolescents, of whom 18 were carefully matched siblings of the IDDM subjects with MA and 21 were similarly matched siblings of the IDDM non-MA subjects. Plasma renin concentration was determined by a direct radioimmunoassay method (Sanofi-Pasteur) and found to be virtually the same in the control and IDDM adolescents as a whole. There was also no real difference between the MA and non-MA subgroups. In contrast, plasma prorenin was significantly higher in the combined IDDM group (197.5 +/- 9.3 vs. control, 134.0 +/- 7.9 pg/ml, P < 0.0001). It was also higher in the MA subgroup than in the non-MA subgroup (226.4 +/- 13.6 vs. 168.5 +/- 10.1 pg/ml, P < 0.001). Interestingly, the 18 control siblings matching the MA subgroup had higher plasma prorenin than the 21 control siblings matching the non-MA subgroup (P < 0.001), suggesting a familial predisposition that precedes detectable diabetes and nephropathy. Our findings confirm and extend reports by other workers that elevated plasma prorenin is associated with incipient nephropathy, manifested by MA. The exclusive renal origin of this prorenin, its role in plasma, and the mechanism responsible for its elevation in IDDM with MA, are yet to be demonstrated, as is the general applicability of these findings to different populations of diabetics, with a higher incidence and severity of complications.

直流グロー放電を用いたイオン窒化プロセスに関する基礎的研究（第１報） 窒化プロセスに対するプラズマ放電の効果

For investigating plasma ion nitriding process, we used two kinds of metals as an objective material ; titanium and an austenitic stainless steel (SUS304). We observed the D.C. glow discharge morphology and also investigated the nitriding situation of metal surface with X-ray diffraction analyses. We measured Vickers hardness of nitrided surfaces.Titanium was able to be nitrided if we only elevated the temperature of specimen and wherever we placed it (as cathode or anode) or exposed it into positive column of the glow plasma. On the other hand, SUS304 was nitrided only when we placed it as a cathode. It is necessary for SUS304 to remove oxide film from the surface. It is concluded that role of plasma in nitriding process is to facilitate removal of the oxide film by means of sputtering.

The role of plasma in advanced accelerators*

The role of plasma in advanced accelerators is reviewed with emphasis on three significant areas of research: plasma guiding of beams in accelerators, plasma focusing of beams in high-energy linear colliders, and plasma acceleration of beams.

Radioimmunoassay for Insulin-Like Growth Factor II(IGF-II).

Insulin-like growth factor II (IGF-II) levels in human plasma were measured in physiological and pathological conditions by radioimmunoassay (RIA) with biosynthetic IGF-II. This RIA was specific for IGF-II and cross-reactivity with IGF-I was 1%. The sensitivity was 15 pg/tube with 50% displacement at 50 pg/tube. The intra- and inter-assay coefficients of variation for IGF-II were 6.3 and 9.3%, respectively. The plasma IGF-II levels in normal adults, patients with hypopituitarism and patients with active acromegaly were 589.6 +/- 15.8, 800.9 +/- 45.6 and 330.3 +/- 24.3 ng/ml, respectively. After human growth hormone (hGH) treatment in hypopituitarism, IGF-II slightly increased, but not significantly. After adenomectomy in patients with acromegaly, IGF-II significantly decreased. These data indicate that IGF-II concentrations in plasma were partially GH dependent. This GH dependency was less than that of IGF-I. IGF-II was low in patients with anorexia nervosa and with liver cirrhosis and high in patients with renal failure. In two cases with extrapancreatic tumor-associated hypoglycemia, plasma IGF-II was increased to 1123.8 and 843.5 ng/ml, and returned to normal after tumor resection. These data showed that IGF-II was partly dependent on GH and nutritional conditions and that IGF-II was the most likely cause of some cases of hypoglycemia with extrapancreatic tumor. This specific and sensitive RIA of IGF-II would be useful in evaluating its physiological and pathological role in plasma and tissue.

Proline-rich protein is a glycoprotein and an acute phase reactant

Proline-rich protein (PRP) is a plasma protein associated with lipoproteins. In an attempt to clarify the biological significance of this protein, we isolated and characterized it and studied the biological role in plasma. PRP was isolated by immunosorber column chromatography and by gel filtration and ion-exchange chromatography. The molecular weight determined by gel filtration chromatography was 352 000, that is, about 5-times larger than the weight determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (73 800), indicating pentamer formation. About 10 or 11 isoproteins (p I 5.89–6.55) were observed by isoelectric focusing gel electrophoresis. PRP contained fucose, mannose, galactose, glucosamine and sialic acid accounting for 8.0% of the dry weight. PRP also had a hydrophilic property, as determined by charge shift electrophoresis. Levels of this protein in the human serum related to triacylglycerol-rich lipoproteins. The concentration of PRP correlated to the erythrocyte sedimentation rate (ESR), the C-reactive protein (CRP) and α 1- and α 2-globulin. Sera from patients with infection and inflammation showed significantly higher PRP levels than those noted in controls. Levels of PRP rose in parallel with ESR and CRP levels following acute myocardial infarction, and the maximal level was noted on the 7th postinfarction day. The PRP levels were elevated during the active phase of pneumonia, followed normalization. These data suggest that PRP is an acute phase reactant and may be important in the metabolism of triacylglycerol-rich lipoproteins.

Mechanism of alloying element vaporization during laser welding

Vaporization of alloying elements is a serious problem in the laser welding of many important engineering alloys. Since the available mass transfer correlations are not applicable for credible assessment of the rates of transport of vaporized species in the gas phase, the role of gas phase mass transfer in the overall vaporization of alloying elements was examined by conducting several critical experiments. The rates of transport of alloying elements in the weld pool were determined from numerically computed fluid flow fields. Since the weld pool is surrounded by plasma during laser welding, the role of plasma in the vaporization of alloying elements was physically modeled by allowing molten copper drops to vaporize isothermally both in the presence and absence of plasma. The transport of alloying elements in both liquid and gas phases was found to be rapid and the overall vaporization rates were controlled by the plasma influenced intrinsic vaporization of alloying elements at the weld pool surface. The experimentally obtained rates of vaporization of alloying elements from laser melted stainless steel weld pools were compared with the corresponding theoretically calculated values.