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At least 595 records · Page 33Linked to original sources
PubMed1987

Use of plasma segments for estimating factor VIII activity in pools of fresh frozen plasma.

This study describes a procedure for estimating the factor VIII activity of pools of fresh frozen plasma destined for fractionation into factor VIII concentrates. This information is useful for estimating overall yields. We compared the factor VIII activity of plasma packs and the attached segments shortly after the production of fresh frozen plasmas, during storage at -30 degrees C for up to 4 weeks, after shipping at -20 degrees C to the fractionation site, after storage at -30 degrees C at the fractionation site, and after cryoprecipitation. The factor VIII activity of the segments and the plasma packs were indistinguishable at all stages except after cryoprecipitation. Our results suggest that, prior to the cryoprecipitation stage, a pool of a representative number of plasma segments can be used to determine the factor VIII activity of the plasma pool to be fractionated.

Blood Preservation↗
PubMed1982

Tissue and plasma concentrations of pregnancy-associated plasma protein-A (PAPP-A): comparison with other fetoplacental products.

Human placental lactogen (hPL), alpha fetoprotein (AFP), prolactin (PRL) and pregnancy-associated plasma protein-A (PAPP-A) were measured by radioimmunoassay in plasma, in homogenates of trophoblast, decidua, chorion, amnion and in amniotic fluid from 10 patients after non-complicated term delivery. Plasma samples and homogenates of trophoblast and decidua were also collected from 10 patients undergoing surgical termination of pregnancy between 7 and 12 weeks gestation. In addition, plasma and endometrial samples from 10 patients undergoing hysterectomy for other indications than malignancy were analysed for comparison. The highest tissue concentrations of hPL, AFP and PRL corresponded in each case to the known site of synthesis. For PAPP-A the highest concentration was found in maternal plasma at term [238.8 +/- 75.6 (SEM) micrograms/ml]. The highest tissue concentration was found at term in the decidua (57.0 +/- 2.0 micrograms/g), more than three times higher than that in the trophoblast (16.9 +/- 5.4 micrograms/g). The concentrations of PAPP-A in endometrial samples from non-pregnant women (1.9 +/- 0.6 micrograms/g) was 40 times higher than that in the corresponding plasma samples (0.05 +/- 0.02 microgram/ml). These observations point to the decidua as a possible source of PAPP-A.

Amniotic Fluid↗
PubMed2006

Plasma exchange-based plasma recycling dialysis system as a potential platform for artificial liver support.

We developed a plasma recycling dialysis (PRD) system based on plasma exchange (PE). In this system, rapid reduction of toxic substances and restitution of deficient essential substances are performed by PE, and subsequent blood purification is performed by dialysis between separated plasma recycled over a purification device and the patient's blood across the membrane of the plasma separator. This study was performed to demonstrate the safety and efficacy of this system. Hyperbilirubinemia was induced by ligating the bile duct in pigs, and 7 days later, only PE for 2 h (group PE) or PE for 2 h followed by PRD for 6 h (group PE + PRD) was performed. The separated plasma was recycled over anion-exchange resin through the extra fiber space of the plasma separator. The safety and efficacy of this system were evaluated based on the values of hemodynamic and laboratory parameters. Transfer from PE to PRD was completed in a few minutes. The hemodynamic status and blood cells counts were stable and hemolysis was not observed during the procedure. In the PE + PRD group, the concentrations of total bile acids continuously decreased (pretreatment, 155.5 +/- 40.6 microM; 2 h [end of PE], 76.1 +/- 14.4 microM; 8 h [end of PRD], 25.8 +/- 9.1 microM) and the value was significantly lower than in the PE group after 6 h. The total bilirubin also continuously decreased during PRD (pretreatment, 55.3 +/- 11.5 microM; 2 h [end of PE], 33.8 +/- 8.4 microM; 8 h [end of PRD], 18.6 +/- 7.7 microM) and was significantly lower than in the PE group after 4 h. No significant change was observed in other laboratory values. This PE-based PRD system allowed a swift transfer from PE to sorbent-based blood purification. The safety of this system was demonstrated and the removal of toxic substances was significant. This study confirmed the clinical utility of this system as a platform for artificial liver support.

Animals↗
PubMed2004

Alginate plasma expander maintains perfusion and plasma viscosity during extreme hemodilution.

Extreme hemodilution was performed in the hamster chamber window model using 6% Dextran 70, lowering systemic hematocrit by 60%. Animals were subsequently divided into three groups and hemodiluted to a hematocrit of 11% using 6% Dextran 70, 6% Dextran 500, and a 4% Dextran 70 + 0.7% alginate solution (n = 6 each group). Final plasma viscosities were 1.4 +/- 0.2, 2.2 +/- 0.1, and 2.7 +/- 0.2 cp, respectively, (P < 0.05, high viscosity vs. low viscosity). Blood viscosities were 2.1 +/- 0.2, 2.9 +/- 0.4, and 3.9 +/- 0.3 cp, respectively. The lowest blood and plasma viscosity group had a significantly lower functional capillary density, 37 +/- 16%, whereas the two high-viscosity solutions were 71 +/- 15% and 76 +/- 12% (P < 0.05, high viscosity vs. low viscosity), respectively. Arteriolar and venular flow in the Dextran 500 and alginate groups was higher than baseline (i.e., normal nontreated animals), whereas the low-viscosity group showed a reduction in flow. These microvascular changes were paralleled by changes in base excess, which was negative for the Dextran 70 group and positive for the other groups. However, tissue Po(2) was uniformly low for all groups (average of 1.4 mmHg). Calculation of tissue oxygen consumption in the window chamber based on the microvascular data, flow, and intravascular Po(2) showed that only the alginate + Dextran 70 solution-exchanged animals returned to baseline oxygen consumption, whereas the other groups were lower than baseline (P < 0.05). These results show that hemodilution performed with high-viscosity plasma expanders yields systemic arterial pressures and functional capillary densities that are significantly higher (P < 0.05) than those obtained with 6% Dextran 70, a fluid whose viscosity is similar to that of plasma. A condition for obtaining these results is that the oncotic pressure of the plasma expander be titrated to near normal, so that autotransfusion of fluid from the tissue into the vascular compartment does not reduce the effects of increasing plasma viscosity and increased shear stress on the microvascular wall.

Alginates↗
PubMed2003

Stress-induced plasma volume change determined using plasma FT-IR spectra.

Our purpose was to determine the plasma-volume (PV) change induced by a physical stress independent of the metabolic events that may interfere with physiological fluid shifts in to and out of the intravascular space. Our methods included using 178 exercise tests of varying duration and intensity for determination of PV change during exercise. Plasma Fourier transform infrared (FT-IR) spectra were used to compare hematocrit change to the total spectral area (4000-500 cm(-1)) and the protein and albumin concentration changes induced by exercise. Our results showed that exercise induced a raise in protein (+10.4 +/- 3.1%) and albumin (+9.8 +/- 3.3%) concentrations that significantly correlated with PV change (14.1 +/- 5.2% of plasma volume; P = 0.05 with protein and albumin concentration changes). However, evolution of the total spectral area obtained from rest-plasma (524 +/- 21 a.u.) and exercise-plasma (611 +/- 26 a.u.; +14.1 +/- 4.8%) FT-IR spectra showed a higher correlation level with PV change (r = 0.98; P = 0.005; S(x/y) = 1.26 a.u.). It is our conclusion that although exercise-induced changes in protein and albumin concentrations were found to correlate with PV change, the use of the total spectral area of the plasma FT-IR spectra allowed a more precise measurement of PV change.

Blood Chemical Analysis↗
PubMed2003

Changes in red blood cell osmotic fragility induced by total plasma and plasma fractions obtained from rats bearing progressive and regressive variants of the Walker 256 tumor.

Two variants (A and B) of the widely employed Walker 256 rat tumor cells are known. When inoculated sc, the A variant produces solid, invasive, highly metastasizing tumors that cause severe systemic effects and death. We have obtained a regressive variant (AR) whose sc growth is slower, resulting in 70-80% regression followed by development of immunity against A and AR variants. Simultaneously with the beginning of tumor regression, a temporary anemia developed (approximately 8 days duration), accompanied by marked splenomegaly (approximately 300%) and changes in red blood cell osmotic fragility, with mean corpuscular fragility increasing from 4.1 to 6.5 g/l NaCl. The possibility was raised that plasma factors associated with the immune response induced these changes. In the present study, we identify and compare the osmotic fragility increasing activity of plasma fractions obtained from A and AR tumor bearers at different stages of tumor development. The results showed that by day 4 compounds precipitating in 60% (NH4)2SO4 and able to increase red blood cell osmotic fragility appeared in the plasma of A and AR tumor bearers. Later, these compounds disappeared from the plasma of A tumor bearers but slightly increased in the plasma of AR tumor bearers. Furthermore, by day 10, compounds precipitating between 60 and 80% (NH4)2SO4 and with similar effects appeared only in plasma of AR tumor bearers. The salt solubility, production kinetics and hemolytic activity of these compounds resemble those of the immunoglobulins. This, together with their preferential increase in rats bearing the AR variant, suggest their association with an immune response against this tumor.

Anemia↗
PubMed1999

Arsenic trioxide and melarsoprol induce apoptosis in plasma cell lines and in plasma cells from myeloma patients.

Recent data have renewed the interest for arsenic-containing compounds as anticancer agents. In particular, arsenic trioxide (As2O3) has been demonstrated to be an effective drug in the treatment of acute promyelocytic leukemia by inducing programmed cell death in leukemic cells both in vitro and in vivo. This prompted us to study the in vitro effects of As2O3 and of another arsenical derivative, the organic compound melarsoprol, on human myeloma cells and on the plasma cell differentiation of normal B cells. At pharmacological concentrations (10(-8) to 10(-6) mol/L), As2O3 and melarsoprol caused a dose- and time-dependent inhibition of survival and growth in myeloma cell lines that was, in some, similar to that of acute promyelocytic leukemia cells. Both arsenical compounds induced plasma cell apoptosis, as assessed by 4',6-diamidino-2-phenylindole staining, detection of phosphatidylserine at the cell surface using annexin V, and by the terminal deoxynucleotidyl transferase-mediated nick end labeling assay. As2O3 and melarsoprol also inhibited viability and growth and induced apoptosis in plasma-cell enriched preparations from the bone marrow or blood of myeloma patients. In nonseparated bone marrow samples, both arsenical compounds triggered death in myeloma cells while sparing most myeloid cells, as demonstrated by double staining with annexin V and CD38 or CD15 antibodies. In primary myeloma cells as in cell lines, interleukin 6 did not prevent arsenic-induced cell death or growth inhibition, and no synergistic effect was observed with IFN-alpha. In contrast to As2O3, melarsoprol only slightly reduced the plasma cell differentiation of normal B cells induced by pokeweed mitogen. Both pokeweed mitogen-induced normal plasma cells and malignant plasma cells showed a normal nuclear distribution of PML protein, which was disrupted by As2O3 but not by melarsoprol, suggesting that the two arsenical derivatives acted by different mechanisms. These results point to the use of arsenical derivatives as investigational drugs in the treatment of multiple myeloma.

Antineoplastic Agents↗
PubMed1999

Increased plasma oxidizability and decreased erythrocyte and plasma antioxidative capacity in patients with NIDDM.

BACKGROUND: Atherosclerosis and microvascular complications in patients with non-insulin-dependent diabetes have been linked to increased oxidative stress. The glutathione redox cycle is a major determinant of the antioxidative capacity of plasma and its constituents. METHODS: We attempted to investigate plasma oxidation and plasma and erythrocyte glutathione and glutathione enzymes in 20 patients with NIDDM, compared with euglycemic matched controls. Plasma oxidation was analyzed both basally (without) and as induced by 2,2'-azobis,2-amidopropane hydrochloride measured by the generation of thiobarbituric acid reactive substances and lipid peroxides. RESULTS: There was a significant increase in oxidation both basally (without) and as induced by AAPH. Plasma glutathione was lowered by 50% (P < 0.01) and erythrocyte glutathione peroxidase, glutathione s-transferase and glutathione reductase activities were lower by 30%, 27% and 46%, respectively (P < 0.01) in the patients with NIDDM. CONCLUSIONS: Confronted by increased oxidation, patients with NIDDM show an abnormal plasma and erythrocyte antioxidative capacity, which may result in an accelerated rate of complications.

Adult↗
PubMed2000

The effect of flow on lysis of plasma clots in a plasma environment.

Fibrinolysis initially generates channels in an occluding thombus which results in blood flow through the thrombus. Since the impact of flow along the surface of a thrombus on thrombolysis has not been investigated in detail, we studied in vitro how such a flow affects lysis. Compacted and noncompacted plasma clots were used as model thrombi. With compacted clots, fibrin-specific lysis induced by alteplase in the outer plasma was accelerated about 2-fold by strong flow (arterial shear rate). Non-fibrin-specific lysis induced either by a high concentration of alteplase or by streptokinase was slow, was accompanied by rapid depletion of plasminogen in the outer plasma, and was only slightly accelerated by flow. With noncompacted clots, similar acceleration factors were documented, when mild flow (venous shear rate) was applied. Strong flow further accelerated fibrin-specific lysis, up to 10-fold as compared to lysis without flow, but paradoxically retarded non-fibrin-specific lysis. The data suggest that flow accelerates lysis by enhancing transport of plasminogen from the outer plasma to the surface of the clot. Both opposite effects of the strong flow were mediated by forceful intrusion of the outer plasma into the noncompacted clot due to flow irregularities. In the case of non-fibrin-specific lysis this resulted in the replacement of the plasminogen-containing milieu by plasminogen-depleted outer plasma in certain areas of the clot turning them into virtually unlysable fragments. This flow-enforced "plasminogen steal" may contribute to the relatively high percentage of incomplete thrombolysis (TIMI-2 grade flow) documented in a number of trials for non-fibrin-specific thrombolytic agents. In the case of fibrin-specific lysis, the effect of flow on the speed of fibrinolysis is always beneficial.

Fibrinolysis↗
PubMed1960

The antihemophilic globulin in plasma; content of freshly frozen single-donor plasma units prepared by the Los Angeles Red Cross Blood Center.

A study was made of the antihemophilic globulin (AHG) content of 16 units of freshly frozen, single-donor, type specific plasma prepared by the Los Angeles Red Cross Blood Center for the treatment of patients with coagulation disorders. Three specimens were examined for each unit-(1) a control sample taken from the donor in a separate small tube, (2) a plasma unit sample before storage, and (3) a plasma unit sample after storage for periods up to one year. From a comparison of the AHG content of Samples 1 and 2, it was found that little AHG was lost in preparing the plasma units. From a comparison of Samples 2 and 3, it was found that a moderate AHG loss (averaging about 20 per cent) occurs on storage. This varied unpredictably from bottle to bottle and was unrelated to the duration of storage. Good AHG activity was found in 4 units after storage for one year. An individual unit of frozen plasma from the Los Angeles Red Cross Blood Center will contain between 50 and 115 per cent AHG activity (with a standard reference sample of plasma taken as 100 per cent).

Blood Coagulation Tests↗
PubMed1991

Longterm followup after treatment of polyarteritis nodosa and Churg-Strauss angiitis with comparison of steroids, plasma exchange and cyclophosphamide to steroids and plasma exchange. A prospective randomized trial of 71 patients. The Cooperative Study Group for Polyarteritis Nodosa.

We attempted to define the most effective treatment for polyarteritis nodosa and Churg-Strauss angiitis, with a prospective, randomized, multicenter trial of cyclophosphamide in conjunction with corticosteroids and plasma exchanges, compared to corticosteroids and plasma exchanges. A total of 71 patients who fulfilled clinical, histological and/or arteriographic diagnostic criteria were randomly designated to receive either prednisone and plasma exchanges (group A, n = 39) or cyclophosphamide, prednisone and plasma exchanges (group B, n = 32). The end points of the study were control of the disease (recovery and remission) and death. Upon study entry clinical and laboratory features did not differ in the 2 groups. Treatment was stopped in 19 patients because of ineffectiveness in 10 (9 in Group A) and side effects in 9 (8 in Group B). Initial control of the disease was similar in both groups. At 5 years, 27 patients had completely recovered and 14 patients were in clinical remission. The cyclophosphamide-prednisone-plasma exchange association was beneficial in preventing relapses during longterm followup. Nineteen deaths were reported during the followup period. There was no difference between the 10 year cumulative survival rates of the 2 groups (respectively, 72 and 75%). Thus, the association of cyclophosphamide with corticosteroids and plasma exchanges reduced the incidence of relapses and improved the quality of the clinical response to therapy.

Adolescent↗
PubMed1990

Net inotropic plasma activity in canine hypovolemic traumatic shock: low molecular weight plasma fraction after prolonged hypotension depresses cardiac muscle performance in vitro.

Numerous studies report controversial results about the occurrence and role of cardiodepressant substances in various forms of circulatory shock. We investigated the net inotropic effect of the low molecular weight fraction (mol wt less than or equal to 1,000) of plasma in prolonged canine hypovolemic traumatic shock using an in vitro guinea pig papillary muscle assay (isotonic mode). The shock plasma fractions (ultrafiltrates) after 4 hr of hypotension (mean arterial blood pressure 40-50 mm Hg) and immediately post-reinfusion significantly depressed papillary muscle function (P less than .02). The extent of papillary muscle shortening was decreased by 49.5 +/- 9.9% in pre- and 50.6 +/- 10.0% in post-reinfusion plasma ultrafiltrates (mean values +/- standard error of the mean; n = 6 shock experiments). In contrast, both the plasma ultrafiltrates from ten non-anesthetized healthy dogs and the control ultrafiltrates obtained prior to onset of shock in the experiments (-6.4 +/- 2.6; n = 6) induced no significant change of the in vitro performance of papillary muscle contraction. These results were achieved with plasma fractions in which ionized calcium and pH were adjusted to concentrations equivalent to the bioassay solution. Lactate acidosis and severe hypoglycemia (1.97 +/- 0.43 mM post-reinfusion) occurred in the shock experiments. Lack of energy substrate (glucose) was not responsible for the in vitro depression. Four depressive shock ultrafiltrates with glucose concentrations adjusted to control ultrafiltrate levels induced a 66.6 +/- 8.8% decrease in the extent of papillary muscle shortening. These results suggest that the possible occurrence of high net negative inotropic activity in plasma, especially just post-reinfusion, may play a role in the pathogenesis of irreversible circulatory shock.

Animals↗
PubMed1989

Differences between values for plasma and serum in tests performed in the Ektachem 700 XR Analyzer, and evaluation of "plasma separator tubes (PST)".

We measured 25 analytes in plasma and serum from the same blood specimen, using the Kodak Ektachem 700 XR Analyzer. For 22 of the analytes, values for plasma were practically the same as those for serum; for the other three, differences between concentrations in plasma and serum were significant, both statistically and medically. Values for the same analytes in plasma from regular heparinized tubes were essentially indistinguishable from those for plasma obtained by use of Plasma Separator Tubes (PST).

Adult↗
PubMed1978

Distribution of IgA 1 and IgA 2 plasma cells in various normal human tissues and in the jejunum of plasma IgA-deficient patients.

The distribution of IgA 1 and IgA 2 plasma cells was studied in normal human tissues. IgA 2 is a minor constituent in peripheral lymph nodes as well as in serum and in bone marrow plasma cells. An increased proportion of IgA 2 plasma cells was observed in gastric and intestinal mucosa, as well as in bronchial mucosa and salivary and mammary glands. Tonsils and mesenteric lymph nodes exhibit values intermediate between those of central and peripheral lymphoid systems. In patients with plasma IgA-deficiency, IgA 2 is the predominant intestinal IgA plasma cells. This may explain the frequent association of an asymptomatic condition and plasma IgA deficiency.

Adolescent↗
PubMed1981

Effects of furosemide-induced plasma volume reduction on plasma antidiuretic hormone in normal and hypertensive subjects.

Plasma antidiuretic hormone (ADH) was measured before and after furosemide administration in hypertensive patients (essential benign hypertensions with low plasma renin activity) and in normal subjects. Furosemide-induced reduction of plasma volume was about 10% after 2 hours. In normal subjects, plasma ADH rose progressively till the end of the study (1.5 pg/ml per hour corresponding to about 3 pg/ml per liter of plasma water lost) whereas it remained unchanged in hypertensive patients. There was an early increase of plasma renin activity (PRA) in normal subjects followed by a progressive fall. PRA response was blunted in hypertensive patients. These results show that volume-dependent ADH secretion is inhibited in patients with essential benign hypertension.

Adult↗
PubMed1996

Platelet inhibitory effect of nitroglycerin in platelet-rich plasma: relevance of glutathione-s-transferases in plasma.

BACKGROUND: Nitroglycerin (NTG) is believed to exert its platelet inhibitory effect via its biotransformation to nitric oxide (NO). We examined the relevance of glutathione-s-transferases (GST) in plasma in the conversion of NTG to NO and the platelet inhibitory effect of NTG. METHODS AND RESULTS: Nitroglycerin (1-100 micrograms/mL) was incubated with human platelet-rich plasma (PRP) for 10-60 minutes. Nitroglycerin caused a concentration-dependent inhibition of platelet aggregation in PRP with IC50 approximately 50 micrograms/mL. NTG also enhanced nitrite levels in PRP and stimulated cyclic GMP accumulation in platelets. In contrast, when NTG was incubated with washed platelets (WP) in concentrations as high as 100 micrograms/mL, there was no inhibition of platelet aggregation, formation of nitrite, or accumulation of cGMP. However, treatment of WP suspension with authentic NO exhibited diminished platelet aggregation, suggesting that NTG delivers NO in plasma that subsequently inhibits platelet aggregation. In keeping with this concept, the aggregation inhibitory effect of NTG in PRP was blocked by oxyhemoglobin. The platelet aggregation inhibition by NTG was potentiated by propylthiouracil (600 micrograms/mL), a GST inducer, and antagonized by ketoprofen (100 micrograms/mL), a GST inhibitor. Direct measurement indeed showed significant GST activity in plasma (24 +/- 3 mU/mL). CONCLUSIONS: We suggest that NTG inhibits platelet aggregation in PRP by its biotransformation to NO in plasma. The presence of GST, and perhaps other cofactors, in plasma is relevant in the platelet inhibitory effects of NTG in PRP.

Adult↗
PubMedDate not supplied

[Which patients should be treated with plasma exchange? Indications for plasma exchange therapy].

What is the current opinion on therapeutic plasma exchange, after 20 years of clinical use for numerous patients and disease states? Principles of rational therapy have broken through into the field of therapeutic plasmapheresis during the last decade. Efficacy proven by controlled clinical trials is the prerequisite for determining indications. Superiority of plasma exchange over other therapeutic modalities has been established for only a limited number of rare diseases. Plasma exchange treatment is still actual for plasmatic hyperviscosity syndromes in the course of haematological and rheumatological diseases. Indications for therapeutic plasma exchange in nephrology are narrowed to some forms of Goodpasture's syndrome, rapidly progressive glomerulonephritis with antineutrophil cytoplasmic antibodies and renal insufficiency, and thrombotic thrombocytopenic purpura/haemolytic uraemic syndrome. Plasma exchange therapy is indicated for severe forms of Guillain-Barré syndrome and myasthenia gravis. Therapeutic benefit of plasma exchange was not found by controlled clinical trials in patients with rheumatoid arthritis, systemic lupus erythematosus, polymyositis, dermatomyositis, multiple sclerosis and rejection of kidney allotransplant.

Humans↗