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At least 793 records · Page 44Linked to original sources
PubMed1980

Studied of very low density lipoprotein triglyceride metabolism in an obese population with low plasma lipids: lack of influence of body weight or plasma insulin.

Pima Indians have a high prevalence of hyperinsulinemia, obesity, and diabetes, but they have low plasma cholesterol levels, reduced low density lipoprotein synthesis, and little arteriosclerotic heart disease. To investigate lipoprotein metabolism further in this group, very low density lipoprotein (VLDL) metabolism was studied, using [3H]glycerol as an endogenous precursor of triglyceride (TG) synthesis, in 15 obese Pima nondiabetic males and compared to that of 10 obese and 13 normal weight, normolipidemic, nondiabetic Caucasian males. The resultant kinetic data were analyzed using a multicompartmental model which includes two pathways for VLDL-TG synthesis and a process of stepwise delipidation for VLDL catabolism. As compared to obese Caucasians, the obese Pimas had a lower rate of VLDL-TG synthesis, and a lower proportion of slow pathway for synthesis. The fractional catabolic rate in the Pimas was higher than in either Caucasian group, a larger proportion of VLDL-TG was delipidized at each step, and particle residence time was shorter. When the relation between VLDL-TG metabolism and plasma insulin was examined, plasma insulin levels in the Pima were not correlated with VLDL-TG synthetic rates, catabolic rates, or plasma pools. On the other hand VLDL-TG synthetic rates were correlated with plasma free fatty acid levels. Thus, in this population with low plasma lipids and reduced arteriosclerotic heart disease, VLDL-TG synthesis is low, VLDL-TG catabolism is accelerated, and VLDL pools appear to be insensitive to the influence of body weight and hyperinsulinemia.

Adolescent↗
PubMed1994

Compartmentalization, processing and redistribution of the plasma membrane protein CE9 on rodent spermatozoa. Relationship of the annulus to domain boundaries in the plasma membrane of the tail.

Western blotting, immunofluorescence and immunogold electron microscopy were used to examine the compartmentalization, processing and redistribution of the integral plasma membrane protein CE9 on the spermatozoa of rats, mice and hamsters. In each species examined, spermatozoal CE9 was found to undergo endoproteolytic processing followed by a net redistribution from the posterior-tail domain into the anterior-tail domain of the plasma membrane during epididymal maturation. Compared to spermatozoa of the rat and mouse, those of the hamster were found to express a greater proportion of their CE9 within the anterior-tail plasma membrane domain at all stages of maturation. As a consequence, CE9 was judged to be a suitable marker for two different spermatozoal plasma membrane domains: the posterior-tail plasma membrane domain (spermatozoa from the testis and caput epididymidis of the rat and mouse) and the anterior-tail domain (spermatozoa from the cauda epididymidis of the hamster). Immunogold electron microscopy was used to pinpoint the positions of the boundaries of these CE9-containing plasma membrane domains at a high level of resolution. In each case, the position of the CE9 domain boundary was found to be strongly correlated with that of the subplasmalemmal electron-dense ring known as the annulus. The precise spatial relationship between the CE9 domain boundary and the annulus was, however, found to differ significantly among species and/or as a function of maturation.

Animals↗
PubMed1993

[Changes in plasma atrial natriuretic factor, plasma and urinary cyclic GMP during exercise in coronary patients and healthy subjects].

The concentrations of plasma ANF and plasma and urinary cyclic GMP were measured at rest and during exercise in 12 normal subjects (reference group) and 20 patients with coronary artery disease (coronary group). In both groups, plasma ANF and c GMP increased during exercise and fell one hour after (F = 3.8, p = 0.029 and F = 13.3, p = 0.0001, respectively) whereas the urinary c GMP increased one hour after exercise (F = 5.3, p = 0.029). In the control group, ANF increased on effort and fell during recovery to above its resting value whereas the plasma c GMP remained unchanged throughout the test. In the coronary group, no significant increase in ANF was observed on effort (wide dispersion of values) whereas the c GMP increased during effort and fell to below testing value during the recovery phase. The ANF of the coronary group was globally higher than the ANF of the control group (F = 4.7, p = 0.04). The plasma c GMP of the coronary group was comparable to that of the controls (F = 2.1, p = 0.15) despite higher concentrations at rest (p < 0.05) and during exercise (p < 0.05). However, there was a positive interaction between the efforts of exercise and the pressure of coronary disease on the concentration of plasma c GMP (F = 6.7, p = 0.0024). There was no difference in urinary c GMP between control and coronary subjects (F = 1, p = 0.33).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Plasma and red blood cell magnesium levels and plasma creatinine after a 100 km race.

Magnesium homeostasis is critical for exercise performance. In this report the effect of long distance race on the erythrocyte and plasma magnesium concentration is determined in a group of 7 well-trained male amateur runners. After a 100 km race the plasma Mg2+ levels increased significantly from 0.845 +/- 0.074 to 0.934 +/- 0.099 mmol.l-1 (p < 0.05). However, the intra-erythrocyte Mg2+ concentrations were not modified significantly (2.10 +/- 0.2 mmol.l-1 versus 2.14 +/- 0.12 mmol.l-1). Creatinine plasma levels increased significantly from 73.4 +/- 3.5 mumol.l-1 to 117.6 +/- 19.4 mumol.l-1 (p < 0.01), suggesting impairment of the renal function. A significant positive correlation between plasma magnesium and plasma creatinine, r = +0.65 (p < 0.01) was found. These results suggest that an increase in the magnesium plasma levels could be related to renal failure during long-distance running.

Adult↗
PubMed1993

Contribution of plasma proteinase inhibitors to the regulation of activated protein C in plasma.

Activated protein C (APC), a serine protease, is regulated in plasma by protease inhibitors. This study was undertaken to determine the role of the major plasma inhibitors in regulating APC in plasma. Kinetic analysis and specific immunoassays for APC-inhibitor complexes were used to determine the inhibitors that form complexes with APC. Of the eight plasma inhibitors investigated, four interact with APC: protein C inhibitor (PCI), alpha 1-proteinase inhibitor (PI), alpha 2-antiplasmin (AP) and C1 esterase inhibitor (C1 Inh). The second order rate constants are: 1.3 x 10(4) M-1 s-1 (PCI); 15 M-1 s-1 (PI); 410 M-1 s-1 (AP); and < 6 M-1 s-1 (C1 Inh), with a relative effectiveness of each inhibitor to inactivate APC in plasma: 49:36:15: < 1, respectively. PCI, PI and AP are the major inhibitors of APC in plasma. Low concentrations of APC will be inhibited by PCI with PI and AP playing a secondary role. However, as increasing APC is generated, PI and AP begin to play more important roles as the PCI is consumed.

Enzyme Activation↗
PubMed1993

Decreased plasma lecithin:cholesterol acyltransfer and associated changes in plasma and red cell lipids in uraemia.

Plasma lipids, lecithin:cholesterol acyltransferase (LCAT) activity and erythrocyte lipid composition were compared for a group of newly diagnosed uraemic patients and a group of healthy subjects. Plasma triacylglycerol was increased and both total and high-density lipoprotein (HDL) cholesterol were decreased. A lower percentage of total cholesterol in patients' plasma was in the esterified form and plasma values of the phospholipid, lysolecithin, were also lower. The plasma LCAT activity of uraemic patients, whether expressed as nmol or percentage of cholesterol esterified per hour, was significantly lower than for normals. Both LCAT activity and lysolecithin in uraemic plasma were inversely correlated with the concentration of urea. The lipid composition of erythrocytes from patients was also abnormal, with both free cholesterol and lecithin being increased. These results are consistent with the occurrence of an acquired deficiency of LCAT in uraemia, comparable to that previously described in hepatic disease. The LCAT enzyme is secreted by the liver, and the inverse correlation noted in this study between LCAT activity and urea suggests that the increased urea in renal disease may inhibit the synthesis and secretion of the enzyme by the liver. The resulting reduction in LCAT activity may lead to the accumulation of cholesterol and lecithin in cell membranes and contribute to the overall pathophysiology of renal disease.

Adult↗
PubMed1976

Plasma volume changes after infusion of various plasma expanders.

In the immediate post-operative period after moderate surgical procedures, 1 litre of a colloid solution or saline was given intravenously. The plasma volume expansion after infusion of dextran 70 (Macrodex), hydroxyethylstarch (Volex), polygelatin (Haemaccel), albumin and saline was found to be between 790 and 180 ml. The most efficent plasma expander was dextran, followed by hydroxyethylstarch. Polygelatin and saline did not give full restitution, although twice the calculated loss was infused. Total plasma protein concentration was lowered in all groups in proportion to the dilution, except for the patients given albumin, in whom the concentration of total protein increased. Calculation of the total circulating protein mass showed no decrease during the period immediately after the infusion. This investigation has demonstrated that the most efficient plasma volume expander is dextran but that hydroxyethylstarch offers an almost equal alternative in terms of volume expansion. Dextran, however, exerts an advantageous effect on the microcirculation. As the metabolic pathways of hydroxyethylstarch have not yet been further explored, dextran is preferred when using artificial colloids. Judged by its secondary effects alone, including the influence on plasma protein patterns, albumin seems to be the compound of choice. Polygelatin and saline are not efficient expanders when hypovolaemia is to be corrected rapidly.

Adult↗
PubMed2001

Role of methylene blue-treated or fresh-frozen plasma in the response to plasma exchange in patients with thrombotic thrombocytopenic purpura.

Twenty patients with thrombotic thrombocytopenic purpura (TTP) underwent plasma exchange using either standard fresh-frozen plasma (Group A, n = 13) or methylene blue-treated plasma (Group B, n = 7). Both groups presented similar characteristics except that bilirubin values were higher in Group A (P < 0.05). The complete remission rate was higher in Group A than B (69% versus 57%). The mean number of procedures was higher in Group B (21 +/- 7 versus 11 +/- 3, P < 0.01) and the mean duration of hospitalization was also longer (37 +/- 12 d versus 22 +/- 11 d; P < 0.01). Our study shows that the use of methylene blue-treated fresh-frozen plasma to treat TTP is associated with a higher number of plasma exchanges and greater transfusion requirements without improving clinical results.

Adult↗
PubMed1990

[Comparative study of the efficacy and tolerability of 2 plasma substitutes used as vascular-loading solutions during plasma exchange].

A 4% human albumin solution in association with colloids was tested in an attempt to reduce the cost of replacement fluids during plasma exchange. In a retrospective study, from May 1988 to December 1989, the efficiency and tolerance of gelatin (Plasmion) and dextran 40 (Plasmacair) were compared. Since June 12, 1989, dextran 40 infused only after administration of dextran 1000 (Promit). Seven hundred and forty eight plasma exchanges were performed in 75 patients; 37 received gelatin (7.24 plasma exchanges/patient), 50 dextran (9.6 plasma exchanges/patient) and 12 both solutions after clinical evidence of intolerance to gelatin. No reaction was noted with dextran 40 used alone or in association with haptenic prevention. The gelatin solution induced 2 immediate allergic reactions and one delayed cutaneous reaction. No cross-reactive allergy was observed between the 2 colloids. Dextran 1000 injections were well tolerated. Gelatin infusions were associated with 10 times more episodes of hypovolemia (5.6 versus 0.62%). This difference is probably linked to a faster elimination of gelatin from the vascular compartment and necessitates the infusion of a larger volume of gelatin, as compared to dextran 40, for the same volume of plasma exchanged.

Drug Hypersensitivity↗
PubMed2006

Great apes show highly selective plasma carotenoids and have physiologically high plasma retinyl esters compared to humans.

Great apes are the closest living relatives of humans. Physiological similarities between great apes and humans provide clues to identify which biological features in humans are primitive or derived from great apes. Vitamin A (VA) and carotenoid metabolism have been only partially studied in great apes, and comparisons between great apes and humans are not available. We aimed to investigate VA and carotenoid intake and plasma concentrations in great apes living in captivity, and to compare them to healthy humans. Dietary intakes of humans (n = 20) and, among the great apes, chimpanzees (n = 15) and orangutans (n = 5) were calculated. Plasma retinol (ROH), retinol-binding protein (RBP), retinyl esters, and major carotenoids were analyzed. The great ape diet was higher in VA than in humans, due to high intake of provitamin A carotenoids. Plasma ROH concentrations in great apes were similar to those in humans, but retinyl esters were higher in great apes than in humans. Differences in plasma carotenoid concentrations were observed between great apes and humans. Lutein was the main carotenoid in great apes, while beta-carotene was the main carotenoid for humans. RBP concentrations did not differ between great apes and humans. The molar ratio of ROH to RBP was close to 1.0 in both great apes and humans. In conclusion, great apes show homeostatic ROH regulation, with high but physiological retinyl esters circulating in plasma. Furthermore, great apes show great selectivity in their plasmatic carotenoid concentration, which is not explained by dietary intake.

Animals↗
PubMed1977

Comparison of whole plasma and perchloric acid-extracted plasma assays for carcinoembryonic antigen.

A direct, paired, comparison was made of two plasma radioimmunoassays for carcinoembryonic antigen (CEA), between a perchloric acid-extracted, ammonium sulphate precipitation method; and a whole-plasma, double-antibody method. For both assays the same preparations of standard CEA, 125I-labelled CEA, and anti-CEA serum were used. Plasma samples were taken from young healthy subjects (24), cancer-free hospital inpatients (44) and cancer-proven untreated patients (94). Within-batch and between-batch variation were both greater for the extracted-plasma method. Cancer discriminatory ability was assessed by probabilistic means. With cancer-free inpatients as the reference group, no difference between the assay methods was revealed. With young healthy subjects as the reference group the whole-plasma assay was superior.

Adult↗
PubMed1984

The effect of plasma on platelet function in hypercholesterolemic rabbits and the changes in fatty acid composition of the plasma.

Rabbits were fed with 1% cholesterol-containing standard diet for 1 to 3 months. The arachidonic acid (AA)-induced aggregation of the platelet-rich plasma (PRP) of the control rabbits was accelerated by substitution of hypercholesterolemic plasma. The incorporation of 14C-AA into thromboxane B2 in platelets was increased approximately 1.6 times with PRP and 1.2 times with the washed platelet suspension (WPS) in hypercholesterolemic rabbits as compared with those of the control. Analysis of the fatty acid compositions of phospholipids and total lipids of hypercholesterolemic rabbits revealed an increase in AA of platelets and plasma, and a decrease in docosahexaenoic acid (DHA) in plasma. The AA/DHA ratio of plasma increased dependently on the period of feeding with the high cholesterol diet, and the increase in the ratio was parallel with the acceleration of platelet aggregation by AA in PRP.

Animals↗
PubMed1995

Plasma cryoprecipitation studies: major increase in fibrinogen yield by albumin enrichment of plasma.

The present studies compared fibrinogen yields of cryoprecipitate (Cr) obtained under differing conditions, and focused on yields from albumin enriched plasma. Addition of human albumin to fresh plasma collected into CPDA-1, citrate, or heparin (4 U/ml) resulted in an average of 2.8 fold (+/- 0.34 SD, n = 17) increase in yields of Cr fibrinogen. This albumin effect was shown with undefatted and defatted albumin, fibrinogen yields increasing in the range of 2-6 g of albumin added/dl of plasma and plateauing thereafter. Similarly increased were yields of fibronectin, plasminogen and factor XIII, but not of factor VIII or of von Willebrand factor. By electrophoretic analyses, Cr fibrinogen from albumin enriched and that from untreated plasma did not differ. Fibrin related measurements disclosed that the albumin enhancement of fibrinogen yield did not result form increased fibrin formation in Cr. This enhancement was shown in plasma that had been enriched with soluble fibrin to increase its yield and in that which had been subjected to hirudin, to high ionic strength, or to dilution to decrease its Cr fibrinogen yield. The results suggest a water exclusion effect, inducing cryoprecipitation of otherwise soluble fibrin/fibrinogen complexes.

Albumins↗
PubMed1991

Human plasma fractionation and the impact of new technologies on the use and quality of plasma-derived products.

Recent years brought several important changes in the domain of human plasma derived products. High purity and effective anti-viral treatment became a reality. This radically improved the quality of patient treatment. At the same time recent discoveries in molecular biology paved the way for the production of several crucial plasma components by recombinant technology. In the light of these developments the future possibilities for different plasma components production is widely discussed and the eventual benefit of more expensive technologies is being evaluated. This paper, analyzes and presents methods applied by different producers to obtain plasma derived components preparations. The impact of these technologies, the quality of the products and the future of the plasma industry is being discussed.

Biotechnology↗
PubMed1979

Homeostatic regulation of free retinol-binding protein and free thyroxine pools of plasma by their plasma carrier proteins in chicken.

The mechanism underlying homeostatic regulation of the plasma levels of free retinol-binding protein and free thyroxine, the systemic distribution of which is of great importance, has been investigated. A simple method has been developed to determine the rate of dissociation of a ligand from the binding protein. Analysis of the dissociation process of retinol-binding protein from prealbumin-2 reveals that the free retinol-binding protein pool undergoes massive flux, and that prealbumin-2 participates in homeostatic regulation of the free retinol-binding protein pool. Studies on the dissociation process of thyroxine from its plasma carrier proteins show that the various plasma carrier proteins share two roles. Of the two types of protein, the thyroxine-binding globulin (the high affinity binding protein) contributes only 27% of the free thyroxine in a rapid transition process, despite its being the major binding protein. But prealbumin-2, which has lower affinity towards thyroxine, participates mainly in a rapid flux of the free thyroxine pool. Thus thyroxine-binding globulin acts predominantly as a plasma reservoir of thyroxine, and also probably in the 'buffering' action on plasma free thyroxine level, in the long term, while prealbumin-2 participates mainly in the maintenance of constancy of free thyroxine levels even in the short term. The existence of these two types of binding protein facilitates compensation for the metabolic flux of the free ligand and maintenance of the thyroxine pool within a very narrow range.

Animals↗
PubMed2006

Plasma and plasma products in the treatment of massive haemorrhage.

Massive haemorrhage requires the use of plasma products when it is accompanied by a coagulopathy or when the more than one blood volume has been lost and intractable bleeding continues. The coagulopathy results from haemorrhagic shock, hypothermia, and activation, consumption and dilution of coagulation factors. Plasma products have a critical role in maintaining sufficient levels of coagulation proteins to ensure haemostasis can occur. Fresh frozen plasma is a source of all coagulation proteins and is required when the prothrombin time and activated partial thromboplastin time exceed 1.5 times the normal control. Cryoprecipitate is the plasma product of choice if fibrinogen, the most critical coagulation protein, is required rapidly and to maintain levels at >1g/L. Prothrombin complex concentrates, monocomponent factor therapy and fibrin sealants each have a role in specific clinical settings. Recombinant factor VIIa has now been shown to have a role in massive haemorrhage. Randomised controlled trials are currently underway to determine the optimal dose and timing of its administration. The physiology and management of the coagulation disturbance using plasma products in the massive haemorrhage of specific clinical situations are described.

Blood Coagulation Factors↗
PubMed1987

Divided renal and caval vein plasma renin activity in two-kidney two-clip hypertension in rabbits and variations of blood pressure, plasma volume and renal function following unilateral nephrectomy.

Determinations were made of peripheral plasma renin activity, blood pressure, plasma volume and blood urea nitrogen in rabbit models of two-kidney one-clip, two-kidney two-clip or one-kidney one-clip hypertension that were created by staged operation to produce functionally significant renal artery stenosis. The plasma renin activity in the divided renal veins and inferior caval vein was also measured in animals with two-kidney two-clip hypertension. In rabbits with two-kidney two-clip hypertension the plasma renin activity was significantly higher in the renal vein on the more involved side and comparable in the renal vein on the less involved side and the inferior caval vein. This response pattern of renin secretion, unilateral hypersecretion with contralateral suppression, was identical with that observed in animals with two-kidney one-clip hypertension. In animals with one-kidney one-clip hypertension there was a marked increase in plasma volume and blood urea nitrogen. The renovascular hypertension was in decreasing order of severity in animals with one-kidney one-clip hypertension, those with two-kidney two-clip hypertension and those with two-kidney one-clip hypertension.

Animals↗
PubMed1999

Mature plasma cells as indicator of better prognosis in multiple myeloma. New methodology for the assessment of plasma cell morphology.

The relationship between plasmablastic cells and outcome in multiple myeloma (MM) has been established for nearly 15 years. But the assessment of these cells is not easy to perform and it allows the identification of only a small proportion of patients. We investigated the plasma cell morphology using a progressive evaluation of consecutive criteria: nucleolus, chromatin and nuclear-cellular ratio (N/C). The combination of these three items produces a subclassification where four cellular subtypes identify 93% of the plasma cells, and these subtypes are related to the outcome. The interest of this methodology is to be based on the mature plasma cells that are easier to identify than the plasmablastic cells. These new cell subtypes introduce a new classification for patients: Group 1 includes patients with at least 66% mature plasma cells (P000). Both Group 2 and 3 have less than 66% P000 and are separated by their degree of maturation (Proplasma I > or = Proplasma II + plasmablastic). The distinction of these three groups of patients is highly related to the prognosis (P < 10(-4)). These results have been confirmed on a second group of patients coming from a different institution. In conclusion, we propose a new methodology for the plasma cell evaluation in MM, that is based on the morphological criteria and that has the advantage of identifying an intermediate (30%) subgroup of patients with a prognostic significance.

Algorithms↗