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PubMed1988

Phenol amplifies complement-fixing activity and induces IgG-precipitating activity in grain-dust extract.

The use of phenol as a preservative in extracts of grain dust was found to be associated with an amplification of complement-fixing activity and the appearance of IgG-precipitating activity. Both activities were absorbed by IgG, suggesting that they were due to a single material. Phenol itself neither fixed complement nor formed a precipitate with IgG. 14C-labeled phenol was incorporated into the IgG precipitating material. Both the amplification of complement-fixing activity and the appearance of IgG-precipitating activity in phenol-containing grain-dust extract were dependent on the presence of air and were inhibited by heating the extract before phenol addition. One interpretation of these results is that a component of grain-dust extract, possibly an enzyme, oxidatively modifies phenol to a form that fixes complement and precipitates IgG. The modified material demonstrates properties of a polyphenol (tannin).

Chemical Precipitation↗

PubMed1970

Rapid method for the isolation of lipoproteins from human serum by precipitation with polyanions.

Procedures are described for the isolation of lipoproteins from human serum by precipitation with polyanions and divalent cations. A mixture of low and very low density lipoproteins can be prepared without ultracentrifugation by precipitation with heparin and either MnCl(2) alone or MgCl(2) plus sucrose. In both cases the precipitation is reversible, selective, and complete. The highly concentrated isolated lipoproteins are free of other plasma proteins as judged by immunological and electrophoretic methods. The low density and very low density lipoproteins can then be separated from each other by ultracentrifugation. The advantage of the method is that large amounts of lipoproteins can be prepared with only a single preparative ultracentrifugation. Polyanions other than heparin may also be used; when the precipitation of the low and very low density lipoproteins is achieved with dextran sulfate and MnCl(2), or sodium phosphotungstate and MgCl(2), the high density lipoproteins can subsequently be precipitated by increasing the concentrations of the reagents. These lipoproteins, containing small amounts of protein contaminants, are further purified by ultracentrifugation at d 1.22. With a single preparative ultracentrifugation, immunologically pure high density lipoproteins can be isolated from large volumes of serum.

Acetates↗

PubMed1983

Complement-mediated inhibition of immune precipitation in patients with immune complex diseases.

The ability of human sera to prevent the precipitation of antigen-antibody complexes has been investigated. The early complement components including C3 are required for optimal prevention of immune precipitation, whereas the later components are not required. The sera of 36 of 75 patients with seropositive rheumatoid arthritis (RA), 14 of 32 with SLE and four of 17 with glomerulonephritis exhibited reduced capacities to prevent immune precipitation. In contrast sera from patients with seronegative RA, ankylosing spondylitis, psoriatic arthritis or degenerative joint disease were normal in this respect. In SLE and GN sera hypocomplementaemia was frequently associated but not always with failure to prevent immune precipitation, whereas only a small proportion of the patients with seropositive RA and reduced capacity to retain complexes in a soluble form were hypocomplementaemic. Thus the failure of sera to prevent the precipitation of antigen-antibody complexes is not always associated with hypocomplementaemia.

Antigen-Antibody Complex↗

PubMed1983

[Usefulness of the agar precipitation test for the determination of the antigenic properties of Mycoplasma gallisepticum. I. Double diffusion test in agar gel].

The usefulness of the double diffusion test in agar gel for the analysis of sero-antigenic structure of mycoplasms was exemplified with serotype S6 Mycoplasma gallispeticum. Serum of a high precipitation value obtained on rabbits intradermally vaccinated with a suspension of mycoplasms with a complete Freund's adjuvant was used. As antigens in the reactions with a specific antiserum was applied an ultrasonic disintegrate of the same suspension of mycoplasms, and in order to elucidate an eventual-phenomenon of fusion of precipitation bands, unheated, and heated at 60, 70 and 100 degrees C for 30 min samples of disintegrate. Apart from a normal antiserum, in the studies were also used antiserum absorbed with lyophylized disintegrate of mycoplasms heated at 100 degrees C. The double diffusion test in agar gel was performed in 3 sets: 1. Unabsorbed antiserum and unheated disintegrate, 2. Unabsorbed antiserum, unheated and heated disintegrate, 3. Absorbed antiserum, unheated and heated disintegrate. In the first set of the examinations 12 more or less intensive precipitation bands were found, in the second set of the experiment appeared two accessory bands, and the third set of the experiment enabled visualization of the other accessory line. Generally in the 3 sets of the experiment 15 precipitation lines were noted in Mycoplasma gallisepticum S6. The precipitation bands represented particular antigenic components of the microorganism studied. Among them 7 components was susceptible to 60 degrees C, 4 were susceptible to 70 degrees C, and 4 were not susceptible even to heating at 100 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Agar↗

PubMed1984

Differential precipitation of the Clq subcomponent of the first complement component (C1) by polyethylene glycol from normal human serum and sera of patients with collagen diseases.

Sera were, under strictly standardized conditions, centrifuged in the presence of 0-5% PEG and the Clq concentration in the precipitates was measured by radial immunodiffusion. The presence of circulating immune complexes and rheumatoid factor(s) resulted in a shift of Clq precipitation to lower PEG concentrations. Clq precipitation at 1.5% PEG was shown to be specific for sera containing immune complexes. Under similar conditions addition of aggregated IgG to normal human serum gave rise to Clq precipitation directly proportional to the amount of aggregated IgG. Precipitation of endogenous Clq at 1.5% PEG and assay by radial immunodiffusion may therefore be useful for the detection and quantitation of immune complexes in human serum.

Antigen-Antibody Complex↗

PubMed1983

Quantification of high-density-lipoprotein cholesterol by precipitation with phosphotungstic acid/MgCl2.

We evaluated the use of a modified phosphotungstic acid/MgCl2 precipitation procedure for the precipitation of apolipoprotein B-containing lipoproteins. Precipitation of these lipoproteins [very-low- and low-density lipoproteins, and lipoprotein (a)] is complete, with negligible coprecipitation of high-density lipoprotein subfractions (HDL1, HDL2, HDL3), even in hypertriglyceridemic sera. In comparison with ultracentrifugation, the precipitation method yields, on the average, values that are 0.17 mmol/L lower for cholesterol values but almost identical for apolipoprotein A-I and phosphatidylcholine. Looking for delta 3,5-cholestadiene formed from cholesterol in the precipitation residue, we used "high-performance" liquid chromatography and "high-performance" thin-layer chromatography and found none.

Apolipoproteins↗

PubMed1983

Partial purification of some red cell enzymes utilizing hemoglobin precipitation by zinc salts.

Carrell and Lehmann have reported a method of precipitating Hb that is attractive in terms of its rapidity, simplicity, reversibility, and lack of rigorous conditions. We have applied the methodology to the concentration and partial purification of certain red cell enzyme activities. Twenty-three glycolytic and nonglycolytic enzymes were studied (Table 1). Under conditions where 97% to 98% of Hb was precipitated, recoveries in the supernatant for 14 enzymes ranged from 40% to 100%, with nine activities virtually completely recovered as measured by routine assay. In six instances, only minimal activity was recoverable either in the supernatant or in the precipitate. In the case of those enzymes whose recovered activities in supernatant were large, more rigorous investigation to detect possible zinc-induced alterations is necessary to determine whether the procedure impairs parameters not readily evaluated by routine assay. The effect of the procedure on PK was studied more intensively. The kinetics of the enzyme with PEP and ADP were unaffected, its thermostability appeared not to differ from native PK, and ATP inhibition of activity was normal. Addition of more zinc to the supernatant precipitated PK, which could then be further partially purified by (NH4)2SO4 precipitation. Inclusion of magnesium and substrate PEP in the hemolysate prior to zinc addition increased recovery in the supernatant from 40% to 80%.

Adenosine Triphosphate↗

PubMed1994

Modification of the dextran-Mg2+ high-density lipoprotein cholesterol precipitation method for use with previously frozen plasma.

Although dextran-Mg2+ precipitation produces accurate and precise results for high-density lipoprotein (HDL) cholesterol in fresh plasma and serum, precipitation of frozen specimens with triglycerides > 2.26 mmol/L (> 200 mg/dL) is difficult. We developed a modification that dilutes thawed samples by 35% and increases dextran-Mg2+ reagent to 15% of sample volume. Standard precipitations were performed on 62 fresh EDTA-treated plasma specimens; supernatant solutions were analyzed fresh and after freezing. Standard and modified methods were also performed on thawed, paired plasmas. In specimens with triglycerides < or = 2.26 mmol/L, HDL cholesterol results for all methods were similar. For triglycerides > 2.26 mmol/L, however, bias and precision were significantly affected by freezing, and 38.5% of samples with standard precipitation required additional procedures to produce clear supernatant solutions. HDL cholesterol concentrations for thawed samples with standard precipitation were significantly greater than for fresh samples (P < 0.02), but those for the modified method were not different from fresh samples, and only one specimen required additional steps to produce a clear supernate.

Chemical Precipitation↗

PubMedDate not supplied

Identification and characterization of the sulfate precipitate in GI147211C IV formulation.

GI147211, a water soluble analog of camptothecin, is currently being investigated for the treatment of cancer as a topoisomerase I inhibitor. Precipitate was observed in some samples of a stability lot of the IV clinical formulation after being stored at 5 degrees C for one month. The precipitate was identified as the sulfate salt of GI147211 by various techniques including Environmental Scanning Electron Microscope/Energy Dispersive X-ray (ESEM/EDX) and Ion Chromatography (IC). The cause of the precipitation was proven to be from the presence of residual sulfate ions in ammonium sulfate treated glass vials that were suspected to be improperly washed. The solubility product (Ksp) of the sulfate salt was determined in 5% dextrose solution adjusted to pH 3.5 at 5 degrees C to mimic the clinical formulation and refrigerated storage conditions. The Ksp was also determined at 15 and 33 degrees C to determine the temperature effect on the constant. The stoichiometry of the sulfate salt was determined by solubility experiments using HPLC and IC to be 2:1 (base/salt). Based on the stoichiometry, the Ksp was calculated to be 3.04 x 10(-12), 9.27 x 10(-12) and 9.96 x 10(-11) M3 at 5 degrees C, 15 degrees C and 33 degrees C, respectively. Using the Ksp values, the sulfate threshold in GI147211 Injection when GI147211 sulfate precipitates was determined to be 1.3, 3.8 and 41 ppm at 5, 15 and 33 degrees C, respectively. Further experiments demonstrated that using the proper cleaning techniques the sulfate level in the treated vials was reduced to < 1.3 ppm. The washing cycles for the vials used for clinical supplies were thereafter modified so that the sulfate precipitate would no longer be an issue.

Antineoplastic Agents↗

PubMed1997

Precipitation methods for high-density lipoprotein cholesterol measurement compared, and final evaluation under routine operating conditions of a method with a low sample-to-reagent ratio.

We evaluated six precipitation methods for high-density lipoprotein cholesterol (HDL-chol) determination: the heparin/Mn2+ precipitation reagent method (Hep), two variants of the phosphotungstic acid/Mg2+ method (Tung-L and Tung-B), the dextran sulfate 50,000/Mg2+ method (Dex), the PEG 6000 method (PEG), and the PEG 6000/dextran sulfate 15,000 (PEG/Dex) method. The Tung-B and PEG/Dex precipitation methods have a low sample/precipitation reagent volume ratio (< 0.4). The Tung-B, Dex, PEG, and PEG/Dex methods gave similar values, averaging within 0.1 mmol/L of each other, showing that the precipitation selectivity of these methods is comparable. The precipitation efficiency of Tung-B and Peg/Dex, however, was superior. Ultrafiltration of the supernatants was needed only at triglyceride concentrations > 16.4 mmol/L (undiluted sample) or > 28.0 mmol/L (sample diluted twofold); however, ultrafiltration without dilution was the most accurate method. Results of Tung-B under routine conditions (33 technicians) agreed well with those of the PEG method for 406 normo- and hyperlipidemic plasma samples. By comparison with the HDL-chol method from the Centers for Disease Control and Prevention, the Tung-B method showed a total error of 10.6% which fulfills the criteria of the National Cholesterol Education Program for HDL-chol analysis. In conclusion, with motivated personnel, Tung-B is a reliable, cost-effective method for routine HDL-chol analysis.

Chemical Precipitation↗

PubMedDate not supplied

Concentration of viral vectors by co-precipitation with calcium phosphate.

BACKGROUND: The envelope glycoproteins, surface unit (SU) and transmembrane (TM) of the murine leukemia virus (MLV) are not covalently linked and tend to dissociate upon high-speed centrifugation, leading to loss of vector infectivity. This study describes a gentle and simple method to concentrate MLV vectors or HIV vectors pseudotyped with MLV envelopes. Having a fast and inexpensive method to concentrate large volumes of vector supernatant will facilitate in vivo experiments and clinical trials that require high titer vector stocks. METHODS: The methods employed in the study were co-precipitation of viral supernatant with calcium phosphate, low-speed centrifugation, dialysis, and infection assays with Lac-Z transducing vectors. RESULTS: Murine leukemia virus vectors and HIV vectors pseudotyped with vesicular stomatitis virus glycoprotein (VSV.G) or MLV envelopes were concentrated successfully using the calcium phosphate co-precipitation method. Parameters that influence virus yield and the reproducibility of the method were investigated. The optimized protocol involves virus harvest in serum-free media, co-precipitation using 60mM calcium chloride, pelleting at 2,000 g, resuspending the pellet in a small volume of 0.1M EDTA-saline, and dialysis against saline to remove EDTA. Volumes were decreased from 300 ml to 10 ml, with 50-100% recovery, and titers can be concentrated up to 1,000-fold. CONCLUSIONS: The calcium phosphate co-precipitation method to concentrate virus is applicable to retrovirus and lentivirus preparations. It uses simple techniques and does not require expensive equipment. Multiple rounds of co-precipitation can be carried out if required.

Animals↗

PubMed1998

Aggregation During Precipitation from Solution. A Pore Diffusion-Reaction Model for Calcium Oxalate Monohydrate.

We have studied the precipitation of calcium oxalate monohydrate (COM) from supersaturated saline solutions both as an in vitro model of the formation of human kidney stones and more generally as a model of particle-size enlargement during precipitation from solution. In any precipitation system there are two mechanisms for size enlargement: growth, by which is meant the deposition of ionic or molecular species on crystal surfaces, and aggregation, the process by which crystals collide, adhere to each other, and form new, stable particles. In this paper we report batch precipitation experiments conducted at constant initial supersaturation and varying ratios of calcium to oxalate ions. By comparison with a simple diffusion-reaction model we are able to draw substantial inferences on the processes that control aggregation. We conclude that at constant temperature and agitation, the aggregation rate constant depends only on the cementing rate, which in turn depends on the solution composition and an appropriately formulated Thiele modulus only. Thus, for the first time, it is possible to propose and evaluate a physico-chemical model for the kinetics of aggregation during precipitation from solution. Copyright 1998 Academic Press.

Journal Article↗

PubMed1999

Role of Surface Precipitation in Copper Sorption by the Hydrous Oxides of Iron and Aluminum.

Isotherms were developed at pH 6.9 for adsorption (ADS) and coprecipitation (CPT) of Cu by hydrous oxides of Fe (HFO) and Al (HAO) to study the role of sorbate/sorbent ratio in metal cation removal. For low sorbate/sorbent conditions, HFO had a higher Cu retention capacity than HAO regardless of contact methodology. For either oxide, CPT was consistently more effective than ADS in removing Cu from solution. At high sorbate/sorbent ratios, surface precipitation dominates and the oxide's net cation retention capacity depends on the nature and solubility of the precipitate formed at the oxide-water interface. X-ray diffraction patterns and isotherms of HAO for both ADS and CPT suggest formation of a solid solution [e.g., CuAl2O4(s)] with dramatically lower solubility than Cu(OH)2(s) precipitated in bulk solution. In contrast, Cu precipitated on the HFO surface exhibited a solubility comparable to the bulk precipitated Cu(OH)2(s). Therefore, at high sorbate/sorbent ratios, HAO has a higher Cu "apparent" sorption capacity than HFO. The relative utility of these oxides as metal scavengers thus depends markedly on sorbate/sorbent conditions. Copyright 1999 Academic Press.

Journal Article↗

PubMed2000

Small-Angle X-Ray Scattering Studies on Nucleation Formation of Dextran Precipitation in the Presence of Boron.

In the present study, the nucleation formation process of dextran precipitation in the presence of boron was investigated by small-angle X-ray scattering (SAXS) techniques. The formation mechanism of aggregates or nuclei is very important in the initial step of crystallization. SAXS measurement is an excellent technique for observing these processes. The results of SAXS measurement suggest that boron, as a trace impurity, induces the aggregating of dextran molecules intermolecularly as a process in the nucleation formation of dextran precipitate nuclei and causes precipitation of dextran through an elongation process. These reactions occur readily at low boron concentrations. In fact, boron, which was detected at low levels in dextran solutions, was concentrated in the precipitates. Therefore, an aqueous solution of boron-free dextran should be resistant to precipitation. Copyright 2000 Academic Press.

Journal Article↗

PubMed1975

Ultrastructural study of calcium-containing precipitation in human parathyroid glands.

Using the potassium pyroantimonate technique for ultrastructural localization of cations and X-ray elemental analysis with both energy dispersive and wave-length dispersive systems, calcium-containing precipitates were found in normal, hyperplastic and adenomatous human parathyroid glands. Differences were observed between oxyphil cells, and suppressed, stimulated and active chief cells in the content and localization of intracellular precipitation. The oxyphil cells and suppressed chief cells possessed precipitates mainly in nuclei and medium-sized and large mitochondria, whereas the stimulated chief cells possessed precipitates in normal-appearing and morphologically altered mitochondria, and in smooth-surfaced vacuoles and cytosol. The active chief cells usually showed a rather sparse precipitation.

Adenoma↗

PubMed1976

[Antireticulin antibodies and precipitating antibodies to food proteins in the sera of children with coeliac disease (author's transl)].

Sera from 41 children suffering with histologically proven coeliac disease and from 40 healthy control children were investigated for the presence of antireticulin antibodies and precipitating antibodies to a watery extract of wheat flour and to cow's milk. Antireticulin antibodies were demonstrated by means of indirect immunofluorescence using sections of fresh rat kidney as substrat. For the detection of precipitating antibodies a combination of electrophoresis and immunodiffusion was used. Serum antireticulin antibodies were found in 11/13 children (85%) with active coeliac disease, in 7/17 children (41%) with clinically and biochemically silent coeliac relapse and in 0/16 children with treated coeliac disease. Serum precipitating antibodies to wheat flour and cow's milk were found respectively in 3/13 children (23%) and 2/13 children (15%) with active coeliac disease and in 1/16 children (6%) with treated coeliac disease. Precipitating antibodies could not be detected in the sera of 17 patients with silent relapse of coeliac disease. In the sera of 40 controls neither antireticulin nor precipitating antibodies were detectable. The presence of antireticulin antibodies in serum did not correspond to the presence of serum precipitins to wheat flour and cow's milk. The significance of serum antireticulin antibodies for screening investigations and for follow-up studies is discussed.

Adolescent↗

PubMed1991

Effects of naloxone-precipitated withdrawal after a single dose of morphine on catecholamine concentrations in guinea-pig brain.

The effect of naloxone-precipitated withdrawal after acute morphine was studied on the concentrations of noradrenaline (NA), 4-hydroxy-3-methoxyphenylethyleneglycol (MHPG), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and on the metabolite/parent amine ratios MHPG/NA, DOPAC/DA and HVA/DA, in eight regions of the guinea-pig brain. Guinea-pigs were treated with a single dose of morphine sulphate (15 mg/kg s.c.) or saline (control) and 2h later with naloxone hydrochloride (15 mg/kg s.c.) to precipitate withdrawal. The animals were decapitated at 0.5 h or 1 h after naloxone injections and their brains analysed for monoamine concentrations by HPLC-ECD. At 0.5 h after naloxone-precipitated withdrawal NA and MHPG levels, and the MHPG/NA ratio, were increased in the hypothalamus, and the NA levels were increased in the hypothalamus, medulla/pons and cortex 1 h after naloxone. Naloxone-precipitated withdrawal also produced increased DA metabolism in the cortex, midbrain and medulla 0.5 h later, and in the cortex, hypothalamus and striatum 1 h later. Hence naloxone-precipitated withdrawal from acute morphine treatment produced a complex pattern of increased synthesis and metabolism of NA and DA which varied over time and with the brain region examined.

Animals↗

PubMed1979

Hydroxyl content of solution-precipitated calcium phosphates.

A method is described for determination of the titratable hydroxide ion in calcium phosphate precipitates. The procedure requires accurate analysis of the other titratable species in the crystal lattice but is unaffected by the presence of other lattice constituents or impurities. The method was applied to precipitates that had been previously analyzed by solution thermodynamic techniques, and the results were consistent with the earlier observations. The hydroxide content of the precipitates increased with crystal maturity and with increasing pH of the precipitation medium. The hydroxide content of the amorphous phase and the immediate postamorphous-crystalline transformation phase was shown to be nearly zero. After 3 to 4 days' maturation, the hydroxide content of precipitates prepared at pH values of 7, 8, and 9 was shown to increase to approximately 23, 40, 56% of that required for pure hydroxyapatite.

Calcium Phosphates↗