Plasma Heat Treatment Research Articles

Distribution of 18-hydroxycorticosterone between red blood cells and plasma.

Plasma 18-hydroxycorticosterone (18-OH-B) to aldosterone (aldo) concentration ratios reflect adrenal corticosterone methyloxidase type II activity. This ratio is determined not only by the relative secretion rates of the two steroids but also by differences in binding, distribution, and metabolism. Plasma cortisol alters the distribution of aldo between red blood cells (RBC) and plasma. We postulated that the distribution of 18-OH-B, like that of aldo, is determined by the availability of high affinity binding sites on plasma transcortin. Double equilibrium dialyses demonstrated that 18-OH-B, aldo, and cortisol compete for binding sites on transcortin. Increasing amounts of each of the three unlabeled steroids produced progressive decrements in the binding of all three labeled steroids to transcortin. The affinity of 18-OH-B (2 X 10(6) M-1) for transcortin was intermediate between those of cortisol (3 X 10(7) M-1) and aldo (0.9 X 10(6) M-1). Heat treatment of plasma decreased the binding of 18-OH-B and cortisol to transcortin by 82% and 75%, respectively. Gel filtration of plasma revealed that protein-bound [3H]18-OH-B and [14C]cortisol eluted in the same fractions. The addition of increasing quantities of unlabeled cortisol to whole blood in vitro produced similar increments in RBC to plasma concentration ratios of [3H]18-OH-B and [14C]aldo. The ratio of the percentage of circulating 18-OH-B in plasma to the percentage of circulating aldo in plasma was constant in blood containing low and high cortisol concentrations. Therefore, changes in plasma cortisol have similar effects on the distribution of 18-OH-B and aldo between RBC and plasma.

Plasma Heat Treatment of Titanium and Titanium Alloy Ti-6Al-4V: Effect of Gas Composition and Temperature

The results of investigations into the thermochemical heat treatment of titanium and the titanium alloy Ti-6Al-4V in a glow discharge are reported. The effect of the important process parameters, gas composition and temperature, on the microstructure, microhardness, and mechanism of layer formation has been studied by means of X-ray diffraction and electron microscopy. The microhardness (Knoop) profiles have been measured and related to various heat treatment conditions. It has been found that the microstructure and the microhardness profiles depend strongly on gas composition. The presence of hydrogen in the gas mixture led to hydride formation in pure titanium, while the microstructure of the titanium alloy Ti-6Al-4V was not affected by hydrogen. It was shown that plasma heat treatment in a gas mixture containing carbon resulted in the formation of titanium carbide. At high carbon contents, compound layer formation can be retarded by a deposit of soot on the surface. It has been observed that, in addition to the established methods of nitrogen mass transfer, i.e. implantation of reactive species and reactive sputtering, chemisorption of nitrogen at the surface plays a significant role in layer formation if pure nitrogen gas is used for the plasma heat treatment; however, the addition of carbon to the gas mixture causes variations in the layer formation mechanism.

Heat inhibition of [formula omitted] lipolysis and 14C ibuprofen protein binding in plasma from heparinized uraemic subjects

Protein binding determination in post heparin plasma samples is complicated by the continued post heparin lipase activity, in vitro , during the binding analysis. The decomposition of lipoproteins and accumulation of nonesterified fatty acids (NEFA) results in artifically elevated free fractions of many drugs. This artefact is particularly accentuated in haemodialysis patients who are frequently hypertriglyceridaemic and receive large doses of heparin. Rapid heat treatment (60° for 15 min) of plasma from heparinized uraemic subjects is shown to inhibit the in vitro lipolysis occuring during 2 hours of equilibrium dialysis at 37° (ED). Mean NEFA concentrations in heat treated plasma after ED x = 400 ± 141 μ mol/ L ) were not different (p > 0.05, n = 9) from the baseline values in fresh plasma ( x 351 ± 117 μ mol/ L ) but were considerably less (p < 0.005) than NEFA levels in untreated plasma after ED ( x = 1025 ± 523 μ mol/ L ). The degree on in vitro lipolysis inhibition (92 ± 6.6%) was very much greater than using the chemical inhibitors phenyl methyl sulphonyl fluoride, EDTA, Triton X100 or protamine sulphate. Heat treatment at 60° for 15 min increased the percentage of free 14C ibuprofen in 3.5% isolated human serum albumin from 0.34% to 0.62%. Reduced binding as a result of heat treatment was not observed however in whole plasma. The percentage free ibuprofen in heat treated, whole plasma from both heparinized and non heparinized subjects ( x = 1.22 ± 0.19; n = 29 ) was not different (p > 0.05) from the percentage free determined in plasma from a non heparinized group ( x = 1.16 ± 0.23; n = 15 ). In contrast the % free ibuprofen in untreated plasma from heparinized subjects was markedly higher ( x = 1.56 ± 0.41; n = 24; p < 0.05 ). There was a strong correlation between % free ibuprofen and plasma NEFA concentration (r = 0.8; p < 0.005; n = 68). The heat treatment of plasma for 15 min at 60° is proposed as an effective means of controlling heparin induced lipolysis in vitro and may be valuable in overcoming the post heparin binding artefact.

Hydrogen passivation of deep metal-related donor centers in germanium

Germanium samples diffused with Cr, Co, Cd, Te, S, Se, Zr, and Ti were exposed to a low pressure hydrogen plasma for 2 h at 250 °C. Deep level transient spectrocopy profiling revealed that the deep metal-related donor centers could be divided into three classes: those which were either weakly or strongly neutralized to the depth of the hydrogen incorporation and those which were unaffected by hydrogen plasma heat treatment.

Factor VIII-related antigen pre-peak on crossed immunoelectrophoresis: A non-random phenomenon

The incidence of a “pre-peak” over the well on crossed immunoelectrophoresis of factor VIII-related antigen (VIIIR:Ag) was found to be not significantly different in groups of hemophilia carriers and non-carrier women. Only 10% of hemophiliacs more than three days post-transfusion exhibited the feature. Upon transfusion 5 out of 6 hemophiliacs showed a transient appearance of the pre-peak. It was also present during pregnancy in 6 of 8 normal women, 2 hemophilia carriers and two von Willebrand's patients. The pre-peak pattern was quite reproducible both in the same sample tested on different days and in different samples from the same subject. The pre-peak material shows a line of identity with the VIIIR:Ag arc and can be induced by heat-treatment of plasma and by cryoprecipitation.

Isolation of non-anticomplementary human immunoglobulin by Cohn fractionation of heated plasma.

Heat treatment of human plasma at 56 degrees C eliminates an unstable immunoglobulin fraction. No anticomplementary activity is generated when the remaining heat-stable immunoglobulins are concentrated and purified by the Cohn alcohol method.

Plasma cholesterol esterifying activity in guinea pigs.

Plasma cholesterol esterifying activity has been measured in guinea pigs fed either a control diet or the same diet supplemented with 1% cholesterol. The extent of esterification was found to be similar in the cholesterol-fed and control guinea pigs and somewhat lower than in rats. The initial rate of esterification was also of the same magnitude as that found in rats and humans, and unaffected by dietary cholesterol if autologous plasma was used as substrate. However, LCAT activity from cholesterol-fed guinea pigs was significantly higher than that of control plasma when acting on either control or cholesterol-fed substrate. This suggests that dietary cholesterol increases the amount (or activity) of LCAT but that the substrate is unsuitable or that a necessary cofactor is present in limiting amounts. Heat treatment of guinea pig plasma seems to alter substrate availability to varying degrees. The implications of these findings in relation to substrate specificity and cofactor requirements of guinea pig LCAT are discussed.

Properties of the reticuloendothelial system of the cat.

SummaryIntravascular phagocytic clearance of colloidal carbon and a “RE-test-lipid emulsion” was comparable to that reported for the rat, mouse, and dogs. Clearance of′ a RE-test-lipid emulsion 3 hr after injection of an initial dose was markedly depressed. However, preopsonization of the emulsion with normal cat plasma prior to injection significantly prevented this depression. Phagocytosis of cat liver slices in vitro was found to be dependent on the amount of normal cat plasma in the incubation medium. As the concentration of plasma in the incubation medium was increased, the degree of phagocytic uptake of the RE-test-lipid emulsion increased proportionately. Heat treatment of normal cat plasma destroyed its phagocytic supporting property. Finally, it was found that hemorrhagic hypotension results in about a 50% depression in the clearance of colloidal carbon as compared to nonhemorrhaged controls. The evidence is consistent with the hypothesis that serum opsonins and/or RES-dependent substances may be...

Importance of requirements to produce minimal risk plasma.

The report by Redeker et al 1 stated that 12 cases of serum hepatitis developed among 120 recipients of commercially prepared pooled plasma. Four of these were clinically icteric and eight were not, giving an attack rate for icteric hepatitis of 3%, and for nonicteric hepatitis, 7%—a total of 10%. There were elevations of transaminase values (serum glutamic oxaloacetic transaminase [SGOT], serum glutamic pyruvic transaminase [SGPT]) in all 12 patients, occurring within proper periods of incubation for serum hepatitis. Needle biopsies were performed upon the 12, and the diagnosis was confirmed pathologically. On the basis of this report, the National Research Council's Committee on Plasma and Plasma Substitutes 2 concluded that heat treatment of plasma was ineffective in preventing serum hepatitis. Thereupon, they hastily recommended the discontinuance of the commercial production of plasma and by legal implication, the private production as well. This experience however, appears to be unique