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At least 1,045 records · Page 58Linked to original sources
PubMed1978

Determinants of high blood pressure in salt-deprived renal hypertensive rats: role of changes in plasma volume, extracellular fluid volume and plasma angiotensin II.

1. Rats with indwelling aortic and right atrial cannulae were maintained on a sodium-free diet before and after renal arterial constriction combined with contralateral nephrectomy. Control animals underwent the same protocol except that non-constricting clips were used. 2. Plasma volumes in the salt-deprived animals were lower than previously determined values in animals with free access to sodium. After clipping plasma volume increased in the hypertensive animals. Extracellular fluid volume was increased equally in both normotensive and hypertensive animals on the second postoperative day only. 3. Before clipping and contralateral nephrectomy plasma angiotensin II values were higher than normal. After the operation angiotensin II concentrations fell to normal over a period of 14 days without significant differences between experimental and control groups. 4. It is concluded that high blood pressure after clipping may be in part maintained by increases in plasma volume. However, the results strongly suggest that other renal mechanisms are likely to be of major pathogenic importance.

Angiotensin II↗
PubMed1983

The effects of heat acclimation on plasma volume and plasma protein of females.

Four females were studied during a 10-day heat acclimation regimen consisting of 2 h per day of stationary cycle riding (means = 46% VO2 max) in a hot environment (40 degrees C, 50% RH) to determine the effects of heat acclimation on changes in plasma volume and vascular protein both at rest and during exercise. Changes in plasma volume were calculated from hematocrit and hemoglobin measurements. Plasma volume decreased during each 2-h session on baseline days through heat day 6 (-4.9% to -1.2%). On heat days 8 and 10, there was an expansion of plasma volume during the session (1.4% and 0.8%). This hemodilution was significantly different (P less than 0.05) from the hemoconcentration on baseline through heat day 4. The gain of protein during the 2-h session was not significantly different on any of the heat days from that on baseline days. With acclimation of females to work in the heat, there is an increased ability to maintain the fluid of the vascular compartment during a 2-h exercise session in the heat.

Acclimatization↗
PubMed1984

Decrease of plasma fibronectin concentration following infusion of a gelatin-based plasma substitute in man.

Intravenous infusion of 500 ml of a gelatin-based plasma substitute, Haemaccel, given to healthy volunteers, resulted in a significant decrease of the immunoreactive plasma fibronectin concentration 48 h and 72 h after infusion. One hour after infusion, the ability of fibronectin to bind gelatin was inhibited with a gradual recovery within 48 h. A dextran based plasma substitute, Macrodex, did not have this effect on plasma fibronectin.

Adult↗
PubMed1950

Plasma iron and saturation of plasma iron-binding protein in dogs as related to the gastro-intestinal absorption of radioiron.

The absorption of a test amount of radioactive iron during artificial saturation of the plasma iron-binding protein, by the repeated intravenous injection of small amounts of iron, was measured in three normal and four anemic dogs. The procedure had no detectable influence on the iron absorption of the normal dogs nor on that of two of the anemic dogs. Two other anemic dogs showed some suppression of iron absorption, though the amount absorbed was still in excess of that absorbed by a normal dog. The reasons for this suppression are not clear from these experiments. Artificially raising the plasma iron to normal levels in one anemic dog did not influence the absorption of iron from the gastrointestinal tract nor was a delayed effect noted after the plasma iron had fallen to base line levels after 5 hours of artificial saturation. It appears that the plasma iron-binding protein and its relative saturation play little role per se in the control of iron absorption in dogs.

Anemia↗
PubMed1952

Studies on a proteolytic enzyme in human plasma. VIII. The effect of calcium and strontium ions on the activation of the plasma proteolytic enzyme.

Calcium ions accelerated the activation of the proteolytic enzyme of plasma from its precursor in the globulin fraction. Calcium did not appear to potentiate fibrinolysis by active bovine or human plasma proteolytic enzyme, nor did it accelerate the activation of the precursor of this enzyme by chloroform or by streptokinase. Experiments with partially purified plasma proteolytic enzyme suggested that the acceleratory effect of calcium was mediated indirectly. Since the concentration of calcium which was effective was comparable to that present in plasma, it is possible that the phenomena reported are of biological significance.

Animals↗
PubMed1954

Plasma and tissue proteins produced by non-hepatic rat organs as studied with lysine-epsilon-C14; gamma globulins the chief plasma protein fraction produced by non-hepatic tissues.

The non-hepatic tissues in a perfused "carcass" (caudal half of the rat) maintain some physiological functions for as long as 5 to 6 hours of perfusion, including good clearance of lysine-epsilon-C(14) and glucose from the perfusate, and synthesis of both tissue and plasma proteins. The perfused "carcass" tissues incorporate only small amounts of lysine-epsilon-C(14) into the plasma proteins to an extent not markedly affected by the presence of the gastrointestinal tract, pancreas, spleen, or kidneys. This activity is found only in the globulin fraction obtained by sodium sulfate fractionation. No significant activity was detected in the plasma fibrinogen or albumin fractions. C(14)-labeled plasma proteins obtained from the eviscerated surviving rat 6 hours after intravenous lysine-epsilon-C(14) have been separated by zone electrophoresis. The gamma globulins contain most of the C(14) activity, with small but measurable activity in the beta and alpha globulins, and no activity in the albumin fraction.

Animals↗
PubMed1998

Plasma patterns of tumor necrosis factor-alpha (TNF) and TNF soluble receptors during acute meningococcal infections and the effect of plasma exchange.

In 39 patients with acute meningococcal infections, the plasma concentrations of tumor necrosis factor-alpha (TNF) and its soluble receptors (sRs) TNFsR-p55 and TNFsR-p75 were measured from admission till recovery. At admission, patients with shock had significantly higher TNF, TNFsR-p55, and TNFsR-p75 values than patients without shock. In addition, during the first 24 hours, patients with shock had higher TNFsR-p75 to TNFsR-p55 ratios, indicating that in shock the increase of TNFsR-p75 exceeds that of TNFsR-p55. TNF measured more than 12 hours after admission failed to differentiate between shock and nonshock because TNF concentrations normalized within 12-24 hours. However, because concentrations of TNFsRs remained elevated for 5-6 days, at that time plasma TNFsRs still differentiated between shock and nonshock. Plasma exchange or whole blood exchange (PEBE), performed in 20 patients with shock, accelerated the decrease of plasma TNFsRs. However, because of a rebound after each PEBE session, the overall half-lives of both TNFsRs were not affected by PEBE.

Acute Disease↗
PubMed1984

Plasma exchange in myasthenia gravis complicated with complement activation and urticarial reactions using fresh-frozen plasma as replacement solution.

6 patients with myasthenia gravis (MG) underwent 26 plasma exchanges (PE) using fresh-frozen plasma (FFP) as replacement solution. After each procedure, complement C3 conversion products (C3c) were detected in the plasma of all the patients. 3 patients had one or more attacks of urticaria during or immediately after the procedure. Using 5% albumin-saline solution as plasma replacement solution, complement activation and urticarial reactions were not seen. It is concluded that infusion of FFP to patients with MG should be avoided as it may induce complement activation and allergic reactions.

Adolescent↗
PubMed1982

Endometrial and plasma concentrations of pregnancy-associated plasma protein-A (PAPP-A).

Pregnancy-associated plasma protein-A (PAPP-A), oestradiol and progesterone levels have been measured by radioimmunoassay in plasma and in endometrial homogenates of 20 women undergoing hysterectomy. Results were grouped according to the histological stages of the endometrium. In plasma, oestradiol and progesterone concentrations changed from proliferative to secretory stages in the well-established pattern of the menstrual cycle, but PAPP-A levels did not change. In endometrium, oestradiol levels were high during the proliferative stage and low in inactive and secretory endometrium. Endometrial PAPP-A and progesterone concentrations increased from inactive to secretory stages, but only the increase in PAPP-A was statistically significant. A positive correlation observed between endometrial PAPP-A concentrations and plasma oestradiol/progesterone ratio suggests a possible hormonal control for the presence of PAPP-A in the uterus.

Adult↗
PubMed2006

Storage of platelet-rich plasma-derived platelet concentrate pools in plasma and additive solution.

BACKGROUND: Prestorage pooling of platelet (PLT)-rich plasma (PRP)-derived PLT concentrates (PCs) and storage in either plasma (PS) or an additive solution (AS) is logistically feasible and would result in a product similar to buffy-coat or apheresis PLTs. STUDY DESIGN AND METHODS: On Day 0, PS PRP PCs were pooled with a sterile connecting device into a new 1.3-L storage container (ELX, PALL Medical). AS-PCs were prepared by addition of a new low-pH glucose-containing AS to the PLT sediment. AS-PCs were pooled into a 1.3-L ELX bag containing four tablets of NaHCO3. PC pools were sampled on Days 1, 5, and 7. RESULTS: PS pools containing 5 units had a mean PLT yield similar to the AS pools (39 x 10(10) +/- 3 x 10(10) vs. 37 x 10(10) +/- 6 x 10(10); p = 0.25). All pools had WBC counts of less than 1 x 10(6). pH and HCO3 decreased in PS pools with storage, but either increased or remained constant in the AS pools. On Day 7, no differences were seen in morphology score or extent of shape change. Hypotonic shock response was better preserved in the plasma pools (71 +/- 12% vs. 56 +/- 13%, p < 0.01); however, surface P-selectin was expressed less in the AS pools (6 +/- 4% vs. 18 +/- 10%, p < 0.01). CONCLUSION: Manufacture and storage of PRP-PCs in pools either in plasma or in a glucose-containing AS in this new container are feasible, and there is good preservation of PLT quality to Day 7.

Blood Platelets↗
PubMed2006

Effect of repeated freeze-thaw cycles on routine plasma biochemical constituents in canine plasma.

BACKGROUND: The effect of repeated freeze-thaw cycles on plasma constituents has not been assessed in dogs, although such a procedure is not uncommon to use in routine laboratory practice. OBJECTIVE: To assess the effect of freeze-thaw cycles on routine plasma constituents in healthy dogs. METHODS: Six healthy adult dogs were used. Blood was sampled and placed in heparinized tubes. After centrifugation, plasma was separated into 5 aliquots. One aliquot was considered as the reference aliquot and used immediately for the assay of all of the biochemical constituents. All of the other aliquots were stored at 20 degrees C. Three aliquots underwent 1, 2, or 3 freeze-thaw cycles during a 1- to 3-day period. The last aliquot remained at 20 degrees C throughout the study and was thawed on the third day. The following biochemical constituents were assayed: glucose, urea, creatinine, total proteins, sodium, potassium, chloride, calcium, phosphates, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), and alkaline phosphatase (ALP). RESULTS: No clinically relevant change was observed between the different aliquots for all of the constituents. CONCLUSION: Repeated freeze-thaw cycles do not cause changes in the biochemical constituents studied in canine plasma.

Alanine Transaminase↗
PubMed1978

The role of plasma volume, plasma renin and the sympathetic nervous system in the posture-induced decline in renal lithium clearance in man.

Excretion of lithium in urine was studied in 2 healthy males while recumbent and while upright, either walking or standing quietly. An oral dose of 24.3 mmol of Lit was taken as three lithium carbonate tablets 13 h before clearance tests. Renal lithium clearance decreased and lithium fractional reabsorption increased while upright. Standing immersed to the neck in water, which prevents the fall in plasma volume upon changing posture from recumbent to upright, prevented the fall in renal lithium clearance as well as the rise in lithium fractional reabsorption while upright. Oral doses of guanethidine (total dose of 200 mg) or oxprenolol (total dose of 140 mg) taken to prevent high levels of sympathetic nervous system activity and plasma renin, respectively, failed to prevent the fall in renal lithium clearance or the rise in lithium fractional reabsorption upon changing posture from recumbent to upright. The findings indicate that the fall in renal lithium clearance and the rise in lithium fractional reabsorption upon changing posture from recumbent to upright is related to the fall in plasma volume but not to high levels of sympathetic nervous system activity or plasma renin activity.

Absorption↗
PubMed1985

Plasma renin activity, blood uric acid and plasma volume in pregnancy-induced hypertension.

UNLABELLED: Plasma renin activity (PRA), plasma aldosterone (PA), blood uric acid (BUA), plasma concentrations of catecholamines (Pcat) and plasma volume (PV) were measured simultaneously in 24 patients with pregnancy-induced hypertension. This hypertensive group was divided into labile (LH) and permanent hypertension (PH) groups according to the response of their blood pressure to home bed rest. As compared to normal theoretical values, PV was decreased in both hypertensive groups (LH = -70%; PH = -14%). As compared to a control group of 16 normotensive pregnant women, PRA was higher in LH and lower in PH whereas PA was lower in both hypertensive groups. In both hypertensive groups, BUA was higher than in the control group. No difference in Pcat was found between the three groups. In the PH group negative correlations were found between BUA and PRA, as well as between BUA and PV, but no correlation between PRA and PV nor between Pcat and BUA were found. CONCLUSIONS: LH and PH are two pathophysiologically different entities in pregnancy-induced hypertension. In PH, renin secretion is not appropriate to hypovolemia and therefore not primarily involved in the pathogenesis of hypertension. The role of hypovolemia in the increase of BUA may be discussed.

Female↗
PubMed1989

Inactivation of hepatitis viruses and HIV in plasma and plasma derivatives by treatment with beta-propiolactone/UV irradiation.

A combined treatment of plasma or plasma derivatives by beta-propiolactone (beta-PL)/UV irradiation is in use at Biotest for the preparation of the virus-safe, stabilized serum (Biseko) and coagulation factor concentrates. The efficacy of this sterilization procedure has been demonstrated for HAV (greater than 8.2 log10), HBV (6.9 log10), NANBHV (greater than 4.5 log10) and HIV (greater than 6.0 log10). The methods used in these studies (titration in chimpanzees or cell cultures) are not applicable in routine monitoring of sterilization processes. We therefore developed a test system using four types of bacteriophages: phi X174, phi e, Kappa and f2. Using these bacteriophages in 88 single tests, sterilization efficacy was regularly monitored during the period from 1981 to 1986. The four types of bacteriophages showed, on average, an inactivation rate of 6.7 log10, independent of size or genome structure. This inactivation is in the range of the inactivation of the relevant pathogenic virus, HBV, by beta-PL/UV. It was shown that under the production conditions of Intraglobin and the other Biotest immunoglobulin preparations, beta-PL (without UV) is as virucidal as the combination of beta-PL/UV in plasma or cryo-poor plasma.

Animals↗
PubMed2004

Assessment of the combined effect of plasma exchange and plasma perfusion on patients with severe hepatitis awaiting orthotopic liver transplantation.

To determine if plasma exchange combined with plasma perfusion is a reliable and effective temporary liver support treatment for patients on the waiting list for OLT, we tested this method in 5 patients with end-stage and 3 patients with middle-stage severe hepatitis. Four patients were successfully controlled until a donor liver was available 4 to 13 days later. In contrast, the remaining 4 patients were not adequately controlled by this treatment and experienced aggravated disease progression, dying 3 to 8 days after treatment while still awaiting OLT. Of those 4 patients who received OLT, 2 patients died from multi-organ failure caused by hepatic failure, while the other 2 survived. These findings show that plasma exchange combined with plasma perfusion provides temporary support for some patients on the waiting list for OLT. The ability of patients to successfully bridge to OLT is closely associated with the degree of liver failure, complications, multi-organ failure, and the length of the waiting period for a donor liver.

Adult↗
PubMed2003

Expression of CD52 on plasma cells in plasma cell proliferative disorders.

Multiple myeloma (MM) and primary systemic amyloidosis (AL) remain incurable disorders, and new treatments targeted to the malignant plasma cells are needed. Alemtuzumab is a humanized monoclonal antibody to CD52 and has activity in chronic lymphocytic leukemia. We examined the CD52 expression on CD45+ and CD45- plasma cell populations to evaluate the potential for using alemtuzumab for these disorders. Bone marrows from 61 patients (29 AL, 23 MM, and 9 MGUS [monoclonal gammopathies of undetermined significance]) were studied using 3-color (CD38/45/52) flow cytometry. Among those with MGUS, MM, and AL, 67%, 52%, and 35%, respectively, were positive for CD52 expression. The CD52 expression was predominantly confined to the clonal CD38+/CD45+ plasma cell fraction with median expression of 68%, 88%, and 82% in MGUS, MM, and AL, respectively, compared with 18%, 6%, and 9% among the CD45- plasma cell population. Clinical trials are warranted in these diseases to learn the therapeutic benefit of anti-CD52 immunotherapy.

Alemtuzumab↗
PubMed1992

[Effect of plasma and plasma components on lymphocyte transformation].

Blood transfusions have an immunosuppressive effect on the recipient and induce changes of several immunological parameters. We therefore studied the effect of homologous and autologous fresh plasma, fresh-frozen plasma, heparinized plasma, as well as the influence of i.v. immunoglobulins on the MLC- and mitogen-induced lymphocyte transformation. We conclude from our study that, besides unspecific mechanisms, an unknown plasma factor enriched in the immunoglobulin fraction suppresses the MLC- and mitogen-induced T-cell immune response.

Humans↗
PubMed1976

Interdependence of Na-excretion, plasma electrolytes, plasma volume and renal Na-K-ATPase-activity in hypertensive rats.

Hypertensive Goldblatt-rats have higher than normal Na-appetite and an enhanced Na-output. They have normal plasma Na- and K-concentration and kidney weight but a significantly reduced plasma volume. The amount of renal membrane protein and the renal Na-K-ATPase-activity of hypertensive rats was found to be significantly below that of controls. In order to evaluate the role of Na-appetite, Na-excretion rate and renal Na-K-ATPase-activity in the electrolyte balance, Goldblatt-rats with a stable hypertension and control animals were put for 8 days on a Na-free diet. Na-excretion rate of control rats reached a minimum (13 muEq/100 g x 24 hr) within 5 days and was maintained on this level up to the end of the experiment. Na-free diet did not alter either the kidney weight or the amount of membrane protein of the animals. However, in salt-free fed control rats total renal Na-K-ATPase-activity was found elevated by about 10% as compared to animals maintained on normal diet. Goldblatt-rats continuously excreted significantly higher amounts of Na (35 muEq/100 g x 24 hr), had sharply reduced plasma volume and plasma Na- concentration. The renal Na-K-ATPase-activity should no adaptation in gold blatt-rats. In all animals studied the rate of Na-excretion showed a close indirect correlation with the renal Na-K-ATPase-activity. It is concluded, that Goldblatt-rats depend on dietary Na to a higher extent than controls because of their reduced capacity to retain Na. The increased Na-appetite of hypertensive rats is a factor secondary to Na-loss.

Adenosine Triphosphatases↗