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PubMed2005

[Effectiveness and mechanism of permanganate enhancing arsenite co-precipitation with ferric chloride].

The effectiveness and mechanism of permanganate enhancing arsenite (As(III)) co-precipitation with ferric chloride is investigated. Effects of parameters such as pH, natural organic matter (NOM) on As removal are studied. Permanganate significantly enhances As(III) removal for ferric co-precipitation (FCP) process. With Fe(III) dosage increasing from 2mg/L to 8mg/L, As removal increased from 41.3% to 75.4% for FCP process; for permanganate oxidation-ferric co-precipitation (POFCP) process, however, corresponsive As removal increased from 61.2% to 99.3% . As removal increased with higher pH for both processes; comparing to FCP process, pH had less effects on As removal for POFCP process; the presence of NOM reduced As removal for FCP process whereas no obvious reduction was observed for POFCP process. Permanganate oxidizing As(III) to As(V) is the main course for enhancing As(III ) removal; furthermore, products of permanganate reduction, hydrous MnO2 (s), also contribute to removing As. POFCP process exhibits good potential of removing As(III ) to assure chemical safety of drinking water.

Arsenites↗

PubMed1976

Enzymatic determinations of cholesterol in high-density-lipoprotein fractions prepared by a precipitation technique.

An enzymatic method for cholesterol in serum [Clin. Chem. 20, 470 (1974)] was initially found to be unsatisfactory for measuring cholesterol in high-density-lipoprotein fractions prepared by precipitation with Mn2+. A fine precipitate formed in the cuvette and cholesterol values were falsely increased. We describe a simple, convenient method for circumventing these problems. An ethylenediaminetetraacetate solution is used to reconstitute the enzymatic reagent. Cholesterol values by this procedure correlated with those obtained by the Lipid Research Clinic's procedure for the same lipoprotein fraction preparations (regression slope, .998; Y-intercept, 8.9 mg/liter; correlation coefficient, .984; standard error of the estimate, 16.8 mg/liter). Precision of the assay, including the precipitation step, was calculated. The SDwithin day was 9.7 mg/liter and SDoverall was 23.7 mg/liter. Results for total cholesterol with the modified reagent were linearly related to concentrations exceeding 4 g/liter, thereby permitting determination of high-density-lipoproteins and total cholesterol in a single run.

Chemical Precipitation↗

PubMed1977

Evaluation of the dual-precipitation method by comparison with the ultracentrifugation method for measurement of lipoproteins in serum.

We evaluated the dual-precipitation method for quantitative measurement of lipoproteins as described by Wilson and Spiger [J. Lab. Clin. Med. 82, 473 (1973)] for normo- and hyperlipemic sera, by comparison with the results obtained with ultracentrifugation. If serum with an above-normal triglyceride concentration is analyzed, the very-low-density lipoprotein cholesterol value obtained with the precipitation method is usually too low. For measurement of high-density lipoprotein cholesterol the ultracentrifugation and precipitation procedures give comparable results, but the latter method is preferred because sinking pre-beta-lipoproteins present in the high-density lipoprotein fraction isolated by means of the ultracentrifuge may result in falsely high values for cholesterol in that fraction. Therefore, at least for the determination of very-low-density lipoprotein cholesterol in hyperlipemic serum, the use of an ultracentrifuge remains necessary. Because few laboratories have an ultracentrifuge at their disposal, it seemed important to look at the stability of sera in view of the forwarding of samples. Also, a way of increasing the efficiency of the ultracentrifuge was studied. Sera can be stored for a week at 4 degrees C or for 54 h at room temperature without noticeable effect on lipoprotein values. Moreover, reliable values can be obtained with an ultracentrifugation time of 8 h (0.8 X 10(8) g-min).

Chemical Precipitation↗

PubMed1978

Multi-laboratory comparison of three heparin-Mn2+ precipitation procedures for estimating cholesterol in high-density lipoprotein.

Plasma high-density lipoprotein is commonly estimated by measuring the cholesterol remaining in plasma supernatant solutions after other lipoproteins, which contain apolipoprotein B, are precipitated with heparin and Mn2+. The method (method I) now in use by the Lipid Research Clinics, in which Mn2+ is at 46 mmol/liter final concentration, is reasonably accurate, but precipitation and sedimentation of lipoproteins other than high-density lipoproteins is often incomplete. We evaluated two modifications of method I. In method II, the Mn2+ concentration was doubled; the second modification (method III) included the increased Mn2+ concentration in a combined heparin Mn2+ reagent, decreased sample volume (2 ml), and a shorter incubation time (10 min at room temperature). The percentages of samples with turbid supernates (i.e., incomplete sedimentation) by methods I, II, and III were 9, 3, and 2%, respectively. Among non-turbid supernates, the percentages of samples containing measurable apolipoprotein B (incomplete precipitation) were 79, 19, and 16%, respectively. We conclude that method III is the most convenient and accurate of the three procedures.

Chemical Precipitation↗

PubMed1989

[Precipitating keratin antibodies in psoriasis vulgaris].

A microprecipitation method was used to test sera of psoriasis patients and control persons for precipitating keratin interfilament antibody (KIF-Ab). Precipitating KIF-Ab were detected in 83% of the psoriasis patients. The sera of only 20.5% of controls without dermatological diseases and 40% of nonpsoriatic patients contained KIF-Ab. The mean KIF-Ab titer of the control and psoriasis group did not differ significantly. The different therapy had different effects on the detectability of precipitating KIF-Ab. Upon completion of dithranol treatment and clinical healing, all sera reacted with KIF from psoriasis scales (pso-sc). PUVA treatment lowered the Ab-titer as well as the number of seropositive sera. These results were confirmed by means of immunoblot and immunodot techniques. Sera from psoriasis patients contained Ab of the IgG and IgM-types against 65, 55 and 45 kD proteins. KIF-IgA-Ab were found frequently in the cases of severe forms of psoriasis.

Adolescent↗

PubMed1978

Preparation of rubella virus haemagglutinating antigen by polyethlene glycol precipitation.

Polyethylene glycol (PEG) was used for precipitation of rubella virus haemagglutinating (HA) antigen from the fluid phase of infected Vero cell cultures, maintained with or without calf serum. In both cases potent antigen preparation were obtained. When the antigen was precipitated from serum-containing medium, higher titres were obtained, provided that substrate or final product were treated with Tween 80 and ether. HA antigen obtained by PET precipitation was entirely valuable in the haemagglutination-inhibition test, as compared with antigens prepared by other methods.

Cell Line↗

PubMed1989

The determination of high density lipoprotein cholesterol separated by electrophoresis and sodium phosphotungstate/Mg2+ precipitation: a physical evaluation.

Epidemiologic studies show that the risk of clinically evident atherosclerosis correlates negatively with concentrations of high density lipoprotein (HDL) and the influence of different factors on variations in the concentration of HDL cholesterol. We measured HDL cholesterol by both the electrophoresis and the precipitation method, and then proposed reference intervals for HDL cholesterol, adjusted for age and sex. Our findings show that the HIDL cholesterol concentration was lowest in cord blood. The concentration increased between the ages of 1 to 15 years, but lowered between the ages of 16 to 20 years. After this age period our study shows that the HDL cholesterol levels began to rise again before leveling off between the ages of 21-30 years. There was a significant difference in concentrations of HDL cholesterol between males and females. Our findings also show that the precision of the precipitation method is better than that of the electrophoresis method. The C.V. of the within-run analysis was 4.8% vs. 10.7%, while the C.V. of the between-run analysis was 4.3% vs. 14.6%. However, a significant correlation (r = 0.77) was noted between the precipitation method and electrophoresis. The electrophoresis method can be recommended as an aid in lipoprotein phenotyping, so we suggest it as a routine clinical method for HDL cholesterol analysis.

Adolescent↗

PubMed1989

[Methodologic studies of the isolation of VLDL using the lipoprotein precipitation reaction in the preparation of apolipoprotein E (Apo E)].

Several lipoprotein precipitation reactions were examined in the isolation of VLDL for apo E phenotyping in comparison to ultracentrifugation. MgCl2-Heparin- and phosphotungstic acid precipitation revealed the best results, although an apo E phenotyping was possible in only 40% of the samples. Ultracentrifugation was unequivocally superior to lipoprotein precipitation reactions.

Apolipoproteins E↗

PubMed1989

Canine common duct and gallbladder bile contain antinucleating factors that inhibit CaCO3 precipitation.

We performed studies involving large incremental additions of calcium to bile to examine the degree of CaCO3 supersaturation that can be achieved in bile, as compared with that in simple NaCl-NaHCO3 solutions. The addition of CaCl2 to bile increased total and free ionized calcium by from four to 12 times their original values and by from two to three times the highest concentrations encountered in bile in vivo. The increase in [Ca++] resulted in fourfold to 12-fold increases in the saturation indexes of bile, with the saturation index reaching as high as 73.4 in a common duct sample. Despite the markedly elevated CaCO3 saturation indexes, evidence of CaCO3 precipitation was not observed in either common duct or gallbladder bile over a 24-hour period. For comparison, calcium added to NaCl-NaHCO3 solutions resulted in the precipitation of CaCO3 within 4 hours if saturation indexes were greater than 12. These results indicate that native bile contains potent antinucleating factors that markedly inhibit CaCO3 precipitation, and they confirm our previous in vivo observations in canine common duct bile.

Animals↗

PubMed1985

[Effect of the method of extracorporeal heparin precipitation of plasma proteins (selective plasmapheresis) on the level of immune complexes in the blood].

A study was made of the effect of selective plasmapheresis (SPP) on the concentration of circulating immune complexes (CIC). The method is based on precipitation at 4 degrees C of plasma fibronectin and associated macromolecular complexes by means of heparin. Sterile plasma of the patient is separated from the precipitate, frozen and kept at -20 degrees C till the next plasmapheresis during which it is returned to the patient instead of the donor's one. All 15 patients examined were exposed to 6 SPP with an interval made every 2 to 5 days. Six patients were diagnosed to have rheumatoid arthritis, 2 systemic lupus erythematosus, 3 hemorrhagic microthrombovasculitis, and 4 multiple sclerosis. The concentration of CIC was measured by precipitation with 3.5% polyethylene glycol before and after SPP, in some cases between sessions. All the patients with rheumatoid arthritis and systemic lupus erythematosus and 2 out of the 3 patients with hemorrhagic vasculitis showed an elevated content of CIC (greater than 0.150 Units OD). The CIC content appeared normal in all the patients with multiple sclerosis. After SPP 4 patients manifested a reduction in the CIC concentration, whereas in 6 it returned to normal. Such a time course correlated with the improvement of other clinical and laboratory findings. It was established that after the first session of SPP the CIC content sharply declined followed by a gradual increment and exceeded the initial values toward the beginning of the second session. After the second SPP the patients manifested the same tendencies. The CIC content reached a maximum by the third SPP and then fell from session to session.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1988

Ammonium sulfate precipitation of the glucocorticoid receptor from rat liver.

The transformed glucocorticoid receptor (GR) from rat liver precipitated at 30% saturation of ammonium sulfate and sedimented at 4.3 S on glycerol gradient centrifugation, whereas the nontransformed GR precipitated at higher concentrations of ammonium sulfate (40-50% saturation) and sedimented at 8.6 S on a gradient. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that heat shock protein 90 (hsp 90) precipitated at 40-50% saturation of ammonium sulfate. Moreover, hsp 90 and the nontransformed GR were eluted from DEAE high performance ion-exchange chromatography at similar salt concentrations (0.22-0.23 M NaCl), whereas the transformed GR was eluted at 0.1 M NaCl. Therefore, hsp 90 seems to be responsible for the surface charge characteristics of the nontransformed GR.

Ammonium Sulfate↗

PubMedDate not supplied

[A critical study of immuno-enzymatic reactions coupled with the precipitation tests on cellulose acetate membranes].

Precipitating tests carried out on cellulose acetate membrane can be increased by treating the immune complexes with enzyme linked anti-immunoglobulin antibodies. From our trials in parastic diseases (Amoebiasis, schistosomiasis, fasciolasis, filariasis, hydatidosis, trichinosis) and mycosis (Aspergillosis, Candidiasis), it seems that the immuno-enzymatic labelling of the "active" precipitating reactions should only be taken in consideration. We must insit on the importance of ELIEDA (enzyme-linked-immuno-electrodiffusion-assay) and ELIDEPA (enzyme-linked-immuno-double-electro-phoresis-assay). Both of these analytical assays are particularly sensitive. The sequence of appearance of the multiple precipitating systems of the complex parasitic mosaic can easily be watched. The different classes of immunoglobulins and their kinetics are determined by the use of monospecific antibodies linked to different enzymes which give a polychromic specific staining.

Amebiasis↗

PubMed1986

Measurement of apolipoprotein B radioactivity in whole blood plasma by precipitation with isopropanol.

A method to measure apolipoprotein B radioactivity in whole blood plasma is described that is suitable for routine use in kinetic experiments in vivo. Radiolabeled apolipoprotein B is precipitated from plasma diluted 15- to 30-fold in the presence of carrier low density lipoproteins by 50% isopropanol. The amount of radioiodine in apoB is estimated from the difference between total radioiodine concentration in whole plasma and the fraction soluble in 50% isopropanol. Addition of up to 100 microliters of plasma to radioiodinated lipoproteins did not alter the percent of radioiodine precipitated in 1500 microliters of 50% isopropanol. The percent of radioiodine precipitated by isopropanol 3 min after intravenous injection of homologous radioiodinated very low density lipoproteins, intermediate density lipoproteins, and low density lipoproteins into rabbits was almost identical to that in the injected lipoproteins (y = 1.009 X +/- 0.462; r = 0.997).

1-Propanol↗

PubMed1986

Detection of circulating immune complexes in liver diseases, systemic lupus erythematosus and glomerulonephritis by polyethylene glycol precipitation.

A method for detection and quantitation of circulating immune complexes using precipitation of the complexes by polyethylene glycol (PEG) has been reexamined to determine the influence of pH on the recovery and the reproducibility of the results. Results showed that the pH optimum for these determinations was 7.8. The recovery percentages range from 57.8-146.5% at lower immune complex concentrations, and from 73.9-101.3% at higher concentrations. The reproducibility of the method seems reasonably acceptable with a percent coefficient of variation ranging from 0.5-9.5. This method for quantitation of circulating immune complexes by polyethylene glycol precipitation is consistent and relatively reliable. Using this method, the levels of circulating immune complexes in sera in patients with hepatitis, liver cirrhosis, hepatoma, acute post-streptococcal glomerulonephritis (before and after treatment) and systemic lupus erythematosus have been examined. The results showed that except the patients with treated acute post-streptococcal glomerulonephritis who had a similar amount of immune complexes with normal controls, the level of immune complexes in patients with other types of diseases were all higher than the control. In addition, the composition of IgG, IgA, IgM, C3 and C4 of the precipitable complexes in sera of patients with three types of liver disease has been analyzed and demonstrated that the percentages of IgM were higher than the normal control. However, C3 and C4 in hepatitis and liver cirrhosis patients were lower than those of the control.

Antigen-Antibody Complex↗

PubMedDate not supplied

[Demonstration and differentiation of circulating immune complexes in chronic inflammatory rheumatic diseases using a semiautomated PEG-precipitation laser nephelometer test].

Circulating immune complexes were determined in rheumatoid arthritis and systemic lupus erythematosus using a semiautomated PEG-precipitation laser-nephelometer technique. Immunoglobulins IgA, IgG and IgM as well as complement proteins C3c and C4 were quantitatively determined in 2.75% PEG-precipitates. The PEG-precipitates obtained from the sera of healthy controls, SLE patients, and RA subjects displayed different protein patterns. In RA sera a significant elevation of all investigated proteins was found. In SLE sera, a significant increase of IgG, IgA, IgM, and C3 was found, whereas C4 was significantly reduced as compared to the controls. Typical values for a calculated IgG/C4 ratio in circulating immune complexes were obtained for RA and SLE. In RA this ratio remained unchanged in different activity stages and was found in seropositive as well as in seronegative sera. Thus circulating immune complexes from SLE and RA sera differ with respect to the degree of complement-dependent solubilization.

Adult↗

PubMed1966

Physico-chemical properties of substances used as molluscicides: precipitation and adsorption.

When molluscicide solutions are applied to natural waters, the active substance may be precipitated or adsorbed and its concentration in the water thus rapidly reduced below the effective minimum. In this paper the authors describe experiments in which factors affecting loss by precipitation and adsorption were examined separately for a number of molluscicidal chemicals. It was found that the amount lost by precipitation depended on the pH of the water and that at a given pH there was a maximum amount of chemical that would remain in solution. The amount lost by adsorption on a standard adsorbent (filter-paper) appeared to be negligible with certain compounds, but with others it was found to depend both on the salt content and on the pH of the water, decreasing with increased dissolved solids and increased pH. It is therefore essential to take into consideration the pH and turbidity of the water before applying molluscicidal treatment.

Adsorption↗

PubMed1981

Antibody precipitation of lipid vesicles containing myelin proteins: dependence on lipid composition.

Antibody binding to human CNS myelin basic protein and to rabbit sciatic nerve myelin P-2 in their lipid-bound and water-soluble conformations has been investigated. 125I-labeled basic protein or P-2 was bound to the surface of liposomes (vesicles) of different acidic lipids, phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidic acid (PA), phosphatidylglycerol (PG), and cerebroside sulfate (CBS). The antibody was prepared against aqueous solutions of basic protein and P-2. Antibody binding to the proteins in liposomes was measured by precipitation of the liposomes by using a double antibody radioimmunoassay. The amount of 125I-basic protein precipitated was lest when the protein was bound to PA and increased in the order PA less than PS less than PG less than CBS less than PE approximately equal to basic protein in solution, suggesting that the antigenic determinants were lest exposed or most altered for PA and most exposed for PE. This agreed fairly well with previously published biophysical studies that suggested that hydrophobic segments of the protein penetrated into the lipid bilayer and that this penetration decreased in the order PA approximately equal to PG greater than PS greater than CBS greater than or equal to PE. The amount of 125I-P-2 precipitated was least for PA and CBS and increased in the order PA approximately equal to CBS less than PS less than PG less than PE approximately equal to P-2 in solution. However, the differences were less than for basic protein and the effect of CBS was different for the 2 proteins. Less is known about the conformation of P-2 in these lipids but it is known that lipids increase its disease-inducing activity. These results indicate that interaction with lipid may sequester or alter the conformation of antigenic determinants such that antibody binding decreases.

Animals↗

PubMed1982

Interference in a chromogenic alpha-amylase assay caused by dye-labeled oligosaccharide-induced precipitation of lipoprotein.

We examined the mechanism by which hypertriglyceridemia interferes with the Roche Diagnostics "Amylochrome" procedure for measurement of amylase in lactescent samples with normal and above-normal amylase activity. The serum blank recommended in the Amylochrome protocol to compensate for lactescence remains inappropriately turbid, compared with the test, and is partly responsible for the underestimation of amylase activity. Other major interference is seen when lipoprotein in hyperlipemic samples with above-normal amylase activity reacts with the soluble oligosaccharide-triazinyl dye product of the Amylochrome assay to form a flocculent blue precipitate. The formation of this precipitate in the test, and its removal, diminish lactescence due to lipemia, an effect that cannot be matched by any manipulation of a serum blank procedure. Oligosaccharide-dye product is removed as a component of the precipitate.

Amylases↗