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PubMed1975

[Identification of proteases of staphylococci by means of an antitrypsin precipitating serum].

Specific antitrypsin precipitating sera obtained by intraconjunctival immunization of rabbits with crystalline trypsin was used to reveal in the supernant of staphylococcal cultures protease having antigenic character common with that of trypsin. This is confirmed by the trypsin accumulation in the process of staphylococcus cultivation, by the inhibition of the proteolytic activity of the antitrypsin precipitating sera and by the production of protein-precipitate as a result of incubation of the supernant with the antitrypsin precipitating sera.

Antigens↗
PubMed1990

Separation processes in biotechnology. Precipitation.

Precipitation has a clear role in downstream processing for product concentration, and ongoing developments promise a more important role in fractionation. Its advantages include adaptability to continuous processing and larger scales, the wide variety of possible precipitants, and the ability to retain biological activity. The focus here has been on precipitation of proteins, but many of the principles apply to nucleic acid removal and precipitation of lower-molecular-weight biological products, such as pharmaceuticals.

Biotechnology↗
PubMedDate not supplied

Human sera with precipitating antibodies to human soluble immune complexes. A brief communication.

INTRODUCTION: Previous numerous papers by the senior author dealt with the human serum factor referred to as anti-antibody which is specifically directed against IgG antibodies that underwent molecular transformation in the course of the reactions with their corresponding antigens. The reactions of this serum factor could be conveniently detected by means of agglutination of Rh-positive erythrocytes sensitized by anti Rh antibodies. No precipitation tests could be developed. MATERIAL AND METHODS: Most studies were conducted by means of double diffusion in gel precipitation. RESULTS: A rheumatoid arthritis serum, G, was noted that produced a strong reaction of double diffusion in gel precipitation with serum samples of a renal graft recipient, T. Further screening detected one more rheumatoid arthritis serum reacting with T; of 28 sera from renal graft recipients, 6 reacted in a similar way to T, but the reactions were considerably weaker and poorly reproducible. Evidence was presented that the precipitin in the two rheumatoid arthritis sera under study had properties of previously described anti-antibody. CONCLUSIONS: Sera with precipitating anti-antibodies may serve as exquisite reagents for detection of soluble immune complexes in human sera.

Antibodies, Anti-Idiotypic↗
PubMed2006

[Adsorption of dissolved organic matter in soil and dissolved organic matter effect on the copper precipitation in high pH range].

Batch experiments were performed to study the dissolved organic matter (DOM) derived from green manure and pig manure sorption in acidic and calcareous soils and the effect of DOM derived from green manure and pig manure compost on the precipitation of copper at different pH in solution. The results showed that there was a significant net release of dissolved organic carbon (DOC) in soil (33.58 mg x L(-1) for calcareous soil and 17.17 mg x L(-1) for acidic soil) when a DOC-free solution was added. As the amount of added DOC increased, the release of DOC from soils decreased. This indicates that parts of the added DOC were sorbed by thesoil material and this effect was influenced by DOM's properties and soil properties. In this experiment the initial mass (IM) isotherm was used to describe the DOM sorption in soil which has been shown to be a useful tool for describing the sorption of DOC insoils because it takes into consideration the release of indigenous DOM from soil. As compared to green manure DOM, pig manure DOM had high m and Kd values, which indicated that it had a higher affinity with soil. As compared to that of green manure DOM, the m and Kd values are 0.4241, 2.946 in acidic soil and 0.2846, 1.58 in calcareous soil, respectively. What's more, the results also indicated that the acidic soil with higher Fe-oxide and Al-oxide content exhibited much higher DOC adsorption ability than calcareous soil rich in 2:1 minerals. In this experiment, green manure and pig manure compost DOM were selected to investigate the effects of DOM on the precipitation-dissolution behavior of copper at different pH. It can be found that DOM can inhibit the copper precipitation especially at high pH range because of the formation of DOM-Cu complex. From pH 6 to pH 10, as compared to the control treatment with no DOM added, the precipitation rate average decreased by 43.6% for the treatment with green manure DOM added and 22.65% for the treatment with pig manure compost DOM.

Adsorption↗
PubMed1978

A comprehensive evaluation of the heparin-manganese precipitation procedure for estimating high density lipoprotein cholesterol.

The accurate quantitation of high density lipoproteins has recently assumed greater importance in view of studies suggesting their negative correlation with coronary heart disease. High density lipoproteins may be estimated by measuring cholesterol in the plasma fraction of d > 1.063 g/ml. A more practical approach is the specific precipitation of apolipoprotein B (apoB)-containing lipoproteins by sulfated polysaccharides and divalent cations, heparin-Mn(2+) being the most commonly used combination. The present heparin-Mn(2+) procedure was found to be reasonably specific and not often subject to large errors; however, 9% (primarily hypertriglyceridemic samples) of the 966 plasma samples treated with heparin-Mn(2+) had obvious supernatant turbidity, indicating incomplete sedimentation of apoB-associated lipoproteins. Furthermore, 48% of the nonturbid supernates contained more than 1 mg/dl (mean 2.5 mg/dl) of apoB-associated cholesterol when measured by a radial immunodiffusion procedure, indicating slight overestimation of HDL cholesterol. Determination of the extent of the unprecipitated apoB-associated lipoproteins by sensitive radioimmunoassay and of the amount of precipitated high density lipoprotein by radial immunodiffusion assay of apolipoproteins A-I and A-II at various heparin and Mn(2+) concentrations indicated that the usual heparin level (approximately 1.3 mg/ml) was adequate. However, a twofold increase in Mn(2+) concentration to 0.092 M improved precipitation of the apoB-associated lipoproteins without excessive precipitation of high density lipoprotein from plasma. This increased Mn(2+) level also provided improved sedimentation of the apoB-associated lipoproteins from hypertriglyceridemic plasma. Additional observations suggested that, for convenience, the heparin and Mn(2+) can be added simultaneously as a combined reagent, that samples can be incubated for 10 minutes at room temperature before centrifugation, and that turbid supernates from hypertriglyceridemic samples can usually be made free of apoB-associated lipoproteins by centrifugation at 12,000 g for 10 minutes.

Apolipoproteins↗
PubMed1986

Evaluation of the dual-precipitation method for determination of cholesterol in high-density lipoprotein subfractions HDL2 and HDL3 in serum.

We compared the dual-precipitation method for measurement of cholesterol in high-density lipoprotein subfractions HDL2 and HDL3 (Gidez et al., J Lipid Res 1982;23:1206-33) with density-gradient ultracentrifugation in a swinging-bucket rotor (Demacker et al., Clin Chem 1983;29:656-63). The concentration of dextran sulfate 15,000 (DS) needed for optimal accuracy of the HDL2-chol and HDL3-chol values was established empirically. At a DS concentration of 0.87 g/L, the values for HDL2-chol as well as for HDL3-chol in 88 sera did not differ significantly from those obtained by ultracentrifugation. The precision of the method was satisfactory and was related to the concentration. Nevertheless, the dual-precipitation method lacks specificity inasmuch as it produces no fractions that contain only one HDL subfraction. HDL2 and HDL3 each contained an equivalent amount of cholesterol from the other. At increasing DS concentrations, some radiolabeled HDL3 appeared to have precipitated prior to complete precipitation of HDL2. This lack of specificity can be tolerated in large-scale epidemiological studies for screening, but not in small-scale intervention studies or in assay of clinical samples, where better accuracy is needed and ultracentrifugation is preferred.

Centrifugation, Density Gradient↗
PubMed1989

Effects of pH and ionic strength on precipitation of phytopathogenic viruses by polyethylene glycol.

The effects of ionic strength of the solution (changed by varying NaCl concentrations or buffer molarity) on the precipitation with polyethylene glycol (PEG) 6000 were studied on phytopathogenic viruses of different morphology: the isometric red clover mottle virus (RCMV), rod-shaped tobacco mosaic virus, flexuous potato virus X (PVX) and bacilliform alfalfa mosaic virus. With increasing NaCl concentration or buffer molarity up to a certain level (0.1 mol/l), the efficiency of PEG precipitation increased. This relationship did not apply to PVX. The effects of pH on PEG precipitation were studied on RCMV. The efficiency of precipitation increased with decreasing difference between pH of the solution and pI of the virus.

Buffers↗
PubMed1989

IgG subclasses of PEG precipitable IgG in systemic lupus erythematosus sera.

Polyethylene glycol (PEG, 4%)-precipitated macromolecular IgG isolated from the sera of 20 patients with systemic lupus erythematosus (SLE) and 15 control subjects was analyzed for its IgG isotype concentration by single radial immunodiffusion. PEG precipitates from SLE sera had higher mean levels of IgG1, IgG2 and IgG3 and lower IgG4 than PEG precipitates isolated from normal sera although only the IgG2 levels were significantly different. Using an anti-complementary assay there was a significant correlation between the ability of parent sera to fix complement and the absolute levels of PEG precipitable IgG1, IgG2 and IgG3. These data suggest that the ability of immune complexes in the sera of patients with SLE to fix complement is dependent on their IgG subclass composition.

Chemical Precipitation↗
PubMed1989

Use of a dual-precipitation procedure for measuring high-density lipoprotein 3 (HDL3) in normolipidemic serum.

We compared results by a dual-precipitation method (J Lipid Res 1982;23:1206-23) for measuring high-density lipoprotein 3 (HDL3) cholesterol with those by ultracentrifugation at d 1.125, using 56 fresh and 105 frozen-stored serum samples. For both methods, HDL2-cholesterol was calculated as the difference between total HDL-cholesterol and HDL3-cholesterol. In general, for pooled serum samples, agreement was closest with ultracentrifugation when we used a dextran sulfate concentration of 5.0 mg/L to precipitate the HDL2-rich fraction, although the optimal concentration varied from 3.0 to 6.8 mg/L for different pools. For individual samples, the values for HDL3 by dual precipitation averaged 12.8% lower than by ultracentrifugation. The coefficients of correlation between the two methods were HDL3, r = 0.70; and HDL2, r = 0.92. The dual-precipitation method reflected the expected sex-related differences in HDL2-cholesterol concentration and inverse relationship with triglyceride concentration.

Adult↗
PubMed1988

Falsely high high-density lipoprotein triglyceride values by the heparin-manganese precipitation method.

Recent evidence indicates that high-density lipoprotein triglyceride (HDL-Tg) may be a predictor of coronary artery disease. We examined three methods for HDL-Tg measurement, comparing results obtained by measurement of Tg in the supernate after heparin-manganese chloride (heparin-Mn) precipitation of EDTA-treated plasma (I) with results obtained after preparative ultracentrifugation (II and III). In II, we used heparin-Mn precipitation of low-density lipoprotein (LDL) from the infranate after ultracentrifugation at d 1.006 to remove very-low-density lipoprotein (VLDL). In III, we performed sequential flotation ultracentrifugation at d 1.006 and 1.063, then measured Tg in the d greater than 1.063 fraction. Method I gave significantly higher HDL-Tg results than II and III, which gave essentially identical results. The difference in results between I and II was not caused by the presence of heparin or manganese chloride, because these were used in both methods. Prior removal of VLDL in II and III resulted in lower HDL-Tg values, and subsequent removal of LDL by precipitation or ultracentrifugation did not alter final HDL-Tg values. The higher values obtained in I were the result of the presence of VLDL-rich unsedimented precipitate in the supernate.

Chemical Precipitation↗
PubMed1988

Precipitable tissue proteins can cause experimental acute renal failure.

UNLABELLED: A previous investigation demonstrated that intravenous infusion of a saline-liver extract into rats causes acute renal failure (ARF), manifested by severe azotemia, extensive cast formation, and patchy tubular necrosis. The purpose of the present study was to explore its pathogenesis. Histologic assessments of rat kidneys made 1.5 hours after liver extract infusion demonstrated eosinophilic material within glomerular capillaries, Bowman's space, and proximal tubular lumina, distal nephron cast formation, and tubular dilation without evidence of tubular necrosis. Renal blood flow at this time was normal but the rats were anuric. Assessments made 24 hours after liver extract infusion demonstrated persisting ARF (blood urea nitrogen, 132 +/- 8; creatinine, 2.54 +/- 0.19 mg/dl), profound cast deposition almost exclusively in the inner medulla/papilla, and the appearance of patchy proximal tubular necrosis. Sephacryl S200 fractionation and 10% polyacrylamide gel electrophoresis of liver extract showed high and low molecular weight proteins (less than 30,000). Proteins in both regions demonstrated prominent acid precipitability (pH 4.5) and autoaggregation (at 37 degrees C). Trace amounts of spontaneously precipitated protein recovered from urine during liver extract infusion demonstrated a predominance of low molecular weight proteins by polyacrylamide gel electrophoresis. Infusing rats with filterable low molecular weight proteins (cytochrome c, ribonuclease, myoglobin) without autoaggregation/acid precipitation characteristics or liver extract made devoid of precipitable proteins failed to induce ARF. However, infusing a kidney extract containing acid precipitating/autoaggregating proteins caused inner medullary/papillary cast formation and ARF. CONCLUSION: normal parenchymal tissues contain proteins which can undergo glomerular filtration and which can spontaneously aggregate under conditions which exist in the distal nephron. If released into the circulation, or if shed from tubular cells into lumina after nephrotoxic or ischemic renal injury, they could help to induce intratubular obstruction and ARF.

Acute Kidney Injury↗
PubMed1988

Differential precipitation of isolated human plasma lipoproteins with heparin and manganese chloride.

We studied the precipitation of isolated lipoproteins with heparin and MnCl2. Lipoproteins were isolated from human plasma by preparative ultracentrifugation and their free cholesterol was labeled. Each lipoprotein fraction was then precipitated at various pHs, with or without bovine serum albumin (60 g/L) present. Under no set of conditions was one class of lipoproteins completely separated from the other two. Specifically, under standard conditions for precipitation of serum lipoproteins (pH 7.4 and protein 60 g/L), 12% of the very-low-density lipoprotein (VLDL) and 8% of the low-density lipoprotein (LDL) remained in the supernatant liquid, and 30% of the high-density lipoprotein (HDL) was precipitated. These results indicate that, under these conditions, so-called HDL cholesterol may be a mixture of VLDL, LDL, and HDL, although the sum of the amount of these three fractions remaining in the supernate is fortuitously very close to the value for HDL cholesterol isolated by ultracentrifugation.

Chemical Precipitation↗
PubMed1979

Effect of reagent pH on determination of high-density lipoprotein cholesterol by precipitation with sodium phosphotungstate-magnesium.

When determining high-density lipoprotein cholesterol by use of sodium phosphotungstate-magnesium precipitation method, I found that the pH of the sodium phosphotungstate reagent was a critical factor in the method. Unless the pH of the reagent was less than 7.6, the precipitation of low-density lipoprotein and very-low-density lipoprotein was incomplete. When the specimen pH was between 7.35 and 8.65, the pH of the serum of plasma did not influence the completeness of precipitation. Optimum concentrations of precipitation reagents, determined after the pH of the sodium phosphotungstate reagent was standardized to pH 6. 15, were 40 g/L for sodium phosphotungstate and 2 mol/L for MgCl2. The distribution of high-density lipoprotein cholesterol in a healthy adult population was skewed to the left for women (n = 34; mean = 660 mg/L) and bi-modal for men (n = 44; mean = 460 mg/mL). The central 95% reference interval was 280 to 880 mg/L for women and 250 to 750 mg/L for men.

Chemical Precipitation↗
PubMed1984

Globin chain precipitation, deranged iron metabolism and dyserythropoiesis in some thalassaemia syndromes.

Electron microscope studies of the erythropoietic cells have revealed two morphologically distinct types of intracellular inclusion in homozygous beta-thalassaemia and HbH disease, presumably reflecting different appearances of precipitated alpha- and beta-chains, respectively. Inclusions resembling those seen in homozygous beta-thalassaemia are also seen in HbE/beta-thalassaemia and to a lesser extent in heterozygous beta-thalassaemia. Dyserythropoietic changes including those indicative of deranged iron metabolism, are seen in some erythropoietic cells in all of the above-mentioned thalassaemia syndromes. Several of these changes are most prominent in homozygous beta-thalassaemia and HbE/beta-thalassaemia, less marked in heterozygous beta-thalassaemia and least prominent in HbH disease. There are gross disturbances of proliferation and protein biosynthesis in erythroblasts in homozygous beta-thalassaemia but not in HbH disease and this difference is reflected in a much greater degree of ineffective erythropoiesis in the former than in the latter. Results of studies into the relationship between the extent of alpha-chain precipitation in individual cells and both the disorder of proliferation and of protein biosynthesis are consistent with the view that these functional disturbances are related to the presence of precipitated alpha-chains and/or an expanded intracellular soluble alpha-chain pool. Some alpha-chains precipitate on centrioles and, presumably, thereby interfere with mitosis. The biochemical changes in the cell membrane of thalassaemic erythroblasts which result in their recognition and phagocytosis by macrophages remain to be determined.

Autoradiography↗
PubMed1984

Electrothermal atomic absorption spectrometric determination of aluminum in serum with a new technique for protein precipitation.

We have studied the electrothermal atomic absorption measurement of aluminum in serum samples by direct analysis with standard additions and the use of a matrix modifier. We have also measured aluminum by analysis of the supernate after pretreatment of serum with concentrated nitric acid to precipitate proteins, and have compared the results obtained by these two techniques. Both appear to eliminate interferences arising from the serum matrix. We quantified the aluminum by utilizing a stabilized temperature (L'vov) platform. Within-run precision (CV) for the standard-additions method was 16.6% (means = 6.5 micrograms/L) and 6.0% (means = 86.8 micrograms/L) and for the protein precipitation method was 10.1% (means = 10.9 micrograms/L) and 4.2% (means = 88.5 micrograms/L). Linearity of the standard curve extended from 0 to 120 micrograms/L for the standard-additions method and from 0 to 100 micrograms/L for the protein precipitation method. Samples from 38 patients were analyzed by both techniques, and linear regression analysis yielded the equation y (protein precipitation) = 1.02 X (standard additions) + 2.04.

Aluminum↗
PubMed1980

Effect of microwave radiation on redissolving precipitated matter in fluorouracil injection.

The effect on the stability of fluorouracil injection of using microwave radiation to redissolve precipitated matter was studied. Fifteen ampuls each of Fluorouracil Injection, USP, containing precipitate were heated to 60 degrees C in a microwave oven and water bath, respectively. The contents of each heated ampul and of 15 control ampuls (unheated, no precipitate) were assayed by high-performance liquid chromatography, and the pH value of each sample was measured. Each test group fell within USP concentration requirements and showed no significant decrease in potency. Among the microwave-heated ampuls, a mean drop of 0.03 pH units was significant (p less than 0.05) but did not affect drug stability or solubility, since all samples remained within the USP pH range of 8.6-9.0. Precipitated matter in fluorouracil injection can be redissolved by heating with microwave radiation without significantly affecting the drug's stability.

Chemical Precipitation↗
PubMed1980

[Comparative study of total cholesterol, HDL cholesterol, LDL + VLDL cholesterol. Two methods: precipitation by concanavalin A and ultra centrifugation (author's transl)].

The authors determined in 3 populations (37 controls, 59 asymptomatic hyperlipemias, and 20 cases of arterial hyperlipemia) the total cholesterol, the HDL cholesterol and the LDL + VLDL cholesterol and their ratio by two methods : precipitation by concanavalin A and ultracentrifugation (AirFuge). These various lipid parameters were compared between 3 populations in order to determine their more or less discriminant character; furthermore, was established the degree of correlation between the results obtained by precipitation with concanavalin A and by ultracentrifugation. The results show : firstly, that the LDL + VLDL was significantly higher and the ratio HDL/LDL + VLDL significantly lower in hyperlipemia and in arterial disease compared with controls ; the HDL was significantly lower in arterial disease than in controls. No lipid parameter permitted one to differentiate between asymptomatic hyperlipemia and arterial disease. Furthermore, the correlation determined by the chi square method was very strong between the results obtained by precipitation with concanavalin A and ultracentrifugation as the coefficient of simple linear regression is very little different from the value + 1. They emphasize the interest of the method of precipitation by concanavalin A which is simple, rapid and very reliable.

Adult↗
PubMed1994

Precipitation profile of the intravenous induction agents.

To investigate the formation of precipitation between various intravenous agents, we cross-matched the anesthetic agents commonly used in the induction phase. Thiopentone and thiamylal precipitated in combination with non-depolarizing muscle relaxants, lidocaine, morphine, and meperidine. Ketamine and etomidate were naive to these agents. Crystalloidal solutions, such as lactated Ringer, normal saline, and dextrose solution did not contribute to the formation of precipitate. In conclusion, our study indicates that intravenous line must be irrigated before and after thiopentone and/or thiamylal. In order to prevent precipitate formation, mixtures of various drugs should be avoided until in vitro assay is done.

Anesthesia, Intravenous↗