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PubMed1990

Uptake of aluminium by human neuroblastoma cells.

We have treated human neuroblastoma cells with various complexes of aluminium, over a range of concentrations, and have measured the amount of aluminium entering the cells after one week, using atomic absorption spectroscopy. We have found that the cells incorporate much higher levels of the element after treatment with aluminium-EDTA than with aluminium-citrate or aluminium-maltol. With aluminium-EDTA, initially the uptake increases with increasing concentration in the medium but eventually reaches a plateau; the concentration within the cells is then higher than that in the medium. No obvious change in morphology of the cells occurs after treatment. The number of cells present after a week's treatment with aluminium-EDTA is lower than that of untreated cells but does not vary over a wide range of aluminium concentrations.

Aluminum↗
PubMed1990

Familial elevation of serum angiotensin converting enzyme activity.

A clustering of high levels of serum angiotensin converting enzyme (S-ACE) was found in an Italian family. The elevation affected five subjects, two of whom were completely healthy and free from known causes of S-ACE increase. The values of S-ACE in hyperACEmic subjects exceeded the values found in normal relatives severalfold. HyperACEmia seemed to be inherited as an autosomal dominant trait. Immunogenetic studies were performed, but we did not find a genetic marker for this condition. The S-ACE activity was inhibited in vitro by edetic acid (EDTA) and SQ 14,225 (captopril). The S-ACE activity was also determined after 1:8 dilution and dialysis against saline of sera. From these experiments we deduced that Lieberman's intrinsic ACE inhibitor was lacking in the hyperACEmic sera. In the presence of remarkable S-ACE increase, a congenital elevation of S-ACE should be considered and it would be useful to perform a familial investigation.

Female↗
PubMed1989

Optimum conditions for the stabilization and measurement of tissue plasminogen activator activity in human plasma.

Current studies show a more than 50-fold variation in the estimated level of tissue-type plasminogen activator (t-PA) activity in normal resting blood samples that result from major differences in the methods used to sample, preserve, and assay t-PA activity in blood. In this study we developed optimized methods for stabilizing and measuring t-PA activity in plasma by using a coupled plasminogen-chromogenic substrate (amidolytic) assay. To maximize the recovery of t-PA activity, blood should be acidified within 60 seconds after being drawn by adding 2 parts whole blood to 1 part 0.5 mol/L sodium acetate, pH 4.2. This method prevents hemolysis and eliminates 70% of the alpha 2-plasmin inhibitor. Optimum conditions for measuring t-PA activity are pH 8.0 to 8.3 (37 degrees C), ionic strength 0.02 to 0.04, 0.5 mumol/L plasminogen, 80 micrograms/ml CNBr-cleaved fibrinogen, and a chromogenic substrate concentration of 0.65 mmol/L D-valyl-leucyl-lysyl-p-nitroanilide, 0.25 mmol/L D-valyl-phenylalanyl-lysyl-p-nitroanilide, or 0.2 mmol/L D-norleucyl-hexahydrotyrosyl-lysyl-p-nitroanilide. The final assay is linear with respect to added one-chain t-PA, two-chain t-PA, and acidified plasma. There was no difference in t-PA activity measured with ethylenediaminetetraacetic acid anticoagulant versus that measured with citrate anticoagulant after correction for dilution effects (average resting t-PA activity in plasma from 20 healthy individuals = 1.59 IU/ml). We conclude that assay conditions can have major effects on the measurement of t-PA activity in plasma and that suboptimal conditions may result in a significant underestimation of t-PA activity.

Citrates↗
PubMed1989

High specific activity [samarium-153] EDTA for imaging of experimental tumor models.

Enriched samarium oxide (98.2% 152Sm2O3) was irradiated in low neutron flux and high neutron flux reactors to produce 153Sm with specific activities of 14.3 GBq and 22.1 TBq mmol-1 Sm, respectively, at the time of use. Formulation of 153Sm as [153Sm]EDTA, with a 1:10 molar ratio of SM:EDTA, provided a stable radiotracer in vitro and in vivo. High specific activity [153Sm]EDTA showed superior uptake in cell culture (20.8 +/- 0.9% vs. 5.5 +/- 0.1% for 6 and 600 pmol Sm per 10(6) cells, respectively) and better tumor index values (51 vs. 37 at 10.9 nmol and 1.09 mumol Sm kg-1, respectively) in the BDF1 mouse/Lewis lung tumor model. High specific activity [153Sm]EDTA scintigrams of Copenhagen x Fisher rats bearing transplanted Dunning R3327 tumors clearly delineated the tumors within 6 hr, with moderate liver and bone uptake and low soft-tissue background. The injected radiotracer underwent rapid central compartment clearance and whole-body elimination. The absence of observed adverse histopathological toxicity combines with high image quality within 6 hr, to support the clinical tumor-imaging potential of this agent. Comparative studies with [67Ga]citrate at molar-equivalent doses indicated that high specific activity [153Sm]EDTA was a superior radiotracer in these in vitro and in vivo models.

Animals↗
PubMed1989

Polarized electric field effects on the regulation of succinate dehydrogenase activity in amphibian muscle and liver: kinetic study.

Electropolarity treatment (0.8 V/DC/Cm) was given to the gastrocnemius muscle of Bufo melanostictus every day for 5 min. for 5 days, and kinetic study of succinate dehydrogenase (SDH) in muscle and liver was conducted with different effectors - sodium malonate, ethylene diamine tetra acetic acid (EDTA), calcium chloride (CACl2) and sodium citrate. Of the four modulators tested, the malonate and EDTA inhibited while sodium citrate and CACl2 activated the enzyme. The significance of the modulation in SDH activity to different extents was discussed.

Animals↗
PubMed1989

Accelerated nonproteolytic cleavage of C3 in plasma from patients with primary biliary cirrhosis.

Complement 3 (C3) with decreased net charge and altered immunoreactivity was detected by crossed immunoelectrophoresis when EDTA plasma from patients with primary biliary cirrhosis was incubated in vitro after reconstitution with Ca++ and Mg++. The alpha and beta chains of this C3 were intact. C3 with decreased net charge was not detected in patients' fresh plasma. Similar C3 alterations were obtained after reaction between native C3 in serum from healthy persons or purified C3 nucleophiles that induce cleavage of the single thioester bond in the alpha chain of C3. This C3 alteration was unchanged when the reaction occurred in the presence of protease inhibitors. The electrophoretically slow C3 fraction was labile in serum on further proteolytic cleavage of C3. It is suggested that accelerated nonproteolytic C3 cleavage in patients with primary biliary cirrhosis facilitates subsequent binding of C3 to C3b receptors and targets of complement attack.

Calcium↗
PubMed1986

Factors influencing the cholesterol esterification rate in lecithin cholesterol acyltransferase radioassay.

Factors affecting the esterification rate of cholesterol by lecithin cholesterol acyltransferase (LCAT E.C. 2.3.1.43) in native cold labelled substrates (human, rabbit, rat serum, plasma, VLDL, LDL depleted serum, rabbit intraocular fluids) repaired by use of ready-made 14C-cholesterol discs (Cholesterol kinetics LCAT-test, UVVVR, Czechoslovakia) were investigated. EDTA added to the serum during the cold incubation (18 h, 0 degrees C-4 degrees C) increased the rate of esterification due to elimination of Ca2+ ions. The similar stimulating effect was found in the presence of mercaptoethanol (ME) in the serum, while in the plasma already stimulated by EDTA no additional effect by ME could be noticed. Freezing and thawing did not affect the fractional esterification rate (FER-per cent of total serum unesterified cholesterol esterified per hour) in normolipidaemic sera, whereas in hyperlipidaemic sera, particularly those with high levels of VLDL, FER was stimulated. Esterification partially proceeded during the cold incubation of serum or plasma with 14C-cholesterol ready-to-use discs, attaining the values of about 0.3%/h and 2-6%/h, respectively, in human sera and in rabbit and rat sera. The starting level of esterification did not affect the linearity of LCAT reaction during warm incubation (30 min at 37 degrees C), neither was the absolute value of FER changed as compared with cold labelled sera with those inhibited by DTNB and reactivated by ME. Substantial LCAT activity was also detected in extremely diluted substrates--such as intraocular fluid collected from rabbits with induced uveitis or after preceding paracentesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Retinol, alpha-tocopherol, lycopene, and alpha- and beta-carotene simultaneously determined in plasma by isocratic liquid chromatography.

Retinol, alpha-tocopherol, lycopene, and alpha- and beta-carotene can be simultaneously determined in human plasma by reversed-phase liquid chromatography. Plasma--0.5 mL plus added internal standard, retinyl acetate--is deproteinized with 0.5 mL of ethanol, then extracted with 1.0 mL of petroleum ether. The organic layer is removed and evaporated, the residue is redissolved in 0.25 mL of ethanol, and 8-microL samples are injected into a 60 X 4.6 mm column of Hypersil ODS 3-microns particles at 35 degrees C. An isocratic methanol mobile phase, flow rate 0.9 mL/min, is used for the 9-min run. Retinol and retinyl acetate are monitored at 305 nm, the tocopherols at 292 nm, and the carotenoids at 460 nm. Between-run CVs were 3.1, 6.9, 6.1, and 6.5% for retinol, alpha-tocopherol, lycopene, and beta-carotene, respectively. Small sample requirement, simplicity of extraction, short run time, and good reproducibility make this procedure ideal for clinical or research use.

Carotenoids↗
PubMed1987

Effect of intravenous sodium loading on renal tubular handling of sodium and water in unilaterally nephrectomized humans.

Glomerular filtration rate (GFR), proximal absolute and fractional reabsorption of isotonic fluid (PAR and PFR) and distal absolute and fractional reabsorption of sodium (DARNa and DFRNa) were measured using the lithium clearance technique in nine unilaterally nephrectomized people (UNP) 1-11 years postnephrectomy and in 14 controls before, during and after an intravenous sodium load. Glomerular filtration rate per kidney was 53% higher in UNP and decreased slightly but significantly (p less than 0.01) in both groups during sodium loading. The PAR per kidney was significantly higher in UNP (p less than 0.01) but PFR was the same as in controls. Both groups responded to sodium loading with a significant decrease in both PAR and PFR. In UNP, DARNa per kidney was significantly higher than in controls (p less than 0.01) but DFRNa was the same in the two groups. Sodium loading resulted in a further increase in DARNa and a decrease in DFRNa in both groups. Both groups responded to sodium loading with a similar increase in fractional sodium excretion. It is concluded that unilateral nephrectomy is followed by an increase in GFR, PAR and DARNa but with maintenance of fractional reabsorption in both proximal and distal tubuli. In response to an intravenous sodium load, the remnant kidney is able to respond in a normal way with a further increase in DARNa. The adjustments necessary to maintain sodium balance after unilateral nephrectomy take place in both proximal and distal tubuli.

Adult↗
PubMedDate not supplied

[Changes in the membrane permeability of erythrocytes in the presence of heparin].

It has been found by the conductometric impulse method that membrane conductivity of human erythrocytes rises about 70 times at heparin concentration in blood samples above 0.2 mg/ml. The presence of edetic acid (EDTA) in blood samples inhibits the rise of membrane conductivity on addition of heparin.

Cell Membrane Permeability↗
PubMed1985

Chelate conjugates of monoclonal antibodies for imaging lymphoid structures in the mouse.

Radiolabeling of a mouse monoclonal antibody (MoAb) specific for the mouse histocompatibility alloantigen IAk expressed by the B lymphocytes of BALB/k and C3H mice but not BALB/c mice was performed by mixing the chelate-labeled anti (alpha) IAk MoAb with purified, no-carrier-added 111In citrate. Labeling efficiency was 85-95%, and the labeled alpha IAk MoAb retained its antigen binding properties in vitro and in vivo. The organ, spleen, and lymph node distribution of intravenously and subcutaneously administered 111In alpha IAk MoAb was compared in mice, two IAk positive and one IAk negative strains, and to 125I alpha IAk MoAb in one IAk positive strain. The 111In alpha IAk MoAb was more stable in vivo compared to 125I alpha IAk MoAb, as shown by a much slower excretion and a higher absolute uptake in lymph nodes and spleen. Lymph node to blood ratio was increased twofold by intravenous anti-EDTA MoAb. Subcutaneous injection permitted clear images of the tiny lymph nodes in the mouse. Potential clinical applications of 111In alpha lymphocyte MoAb include localization of normal lymph nodes and T & B cell leukemias and lymphomas, as well as detecting lymphatic metastases of other cancers. Therapy may also be possible using MoAbs labeled with beta-emitting metal ions such as yttrium-90.

Animals↗
PubMed1985

Stability of ascorbate in urine: relevance to analyses for ascorbate and oxalate.

Ascorbate is unstable in urine at room temperature at pH values ranging from 1 to 12. At pH 7 and above, oxalate is generated in amounts directly proportional to the ascorbate concentration. In 12 different urines, adjusted to pH 12 and incubated for 20 h at room temperature, there was a significant correlation between the amount of oxalate formed and the initial ascorbate concentration (r = 0.97, p less than 0.01). The mean (+/- SD) concentration of oxalate (1.32 +/- 0.70 mmol/L) formed during this period approximated the initial ascorbate concentration (1.57 +/- 1.09 mmol/L). Disodium EDTA, 10 mmol/L final concentration, stabilizes ascorbate in urine and inhibits its conversion to oxalate at pH values of 4.4 to 7.0 during a 24-h period. We therefore propose that urine specimens for ascorbate and oxalate analyses be collected with disodium EDTA present such as to give about this final concentration.

Ascorbic Acid↗