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PubMed1976

Studies on the mechanism of solubilization of immune precipitates by serum.

Antigen (Ag)-antibody (Ab) aggregates prepared with several different antigens are solubilized by fresh serum at 37 degrees C (complex-release activity of serum or CRA). The rate of solubilization varies in different systems and is strongly influenced by the affinity of Ab for the Ag in the immune precipitate. With a given Ag-Ab precipitate, the maximum amount of complex that can be solubilized by individual sera is independent of the initial concentration of complexes and cannot be increased by prolonged incubation. CRA occurs in the absence of C2 and C4, but not in the absence of C3 and factor B of the properdin pathway. Addition of C2 to C2-deficient serum or C4 to C4-deficient serum enhances CRA. Solubilization does not involve extensive degradation of the complexed antibody, as might be detected by acrylamide gel electrophoresis of released antibody after reduction and alkylation to separate H and L chains. Immune precipitates can also be solubilized by incubation with monovalent fragments (Fab or Fab') of antibodies against determinants of the Ab molecules in the immune precipitate. In contrast, F(ab')2 fragments decrease the solubility of the immune precipitates. In view of these findings, we propose that CRA is mediated by the binding of functionally monovalent C fragments (C3 and C4) onto Ab molecules in the precipitates.

Animals↗

PubMed1978

Purification and properties of non-precipitating antibodies to cobrotoxin.

The heterogeneity of precipitating and non-precipitating antibodies to cobrotoxin was demonstrated by their elution pattern on cobrotoxin-Sepharose and chromatography on DEAE-cellulose column. Gel filtration patterns on a Sepharose 6B column revealed that the soluble complexes formed from non-precipitating antibody and HNB-cobrotoxin at a different molar ratio all emerged in the void volume, indicating that the molecular weight of the soluble complex is around 4,000,000 or larger. Unreacted free non-precipitating antibody coincided with the peak of IgG and was proved to be free from HNB-cobrotoxin. The molar ratio of antibody to antigen for the soluble complex was found to be 0.79 to 0.97 indicating that 1.58--1.94 molecules of non-precipitating antibody are bound to HNB-cobrotoxin instead of three molecules as in the case of precipitating antibody.

Antibodies↗

PubMed1997

Precipitation of Arsenic Trisulfide by Desulfotomaculum auripigmentum.

A newly discovered bacterium, Desulfotomaculum auripigmentum, precipitates arsenic trisulfide (As(inf2)S(inf3)). Precipitation of As(inf2)S(inf3) by this organism results from its reduction of As(V) to As(III) and S(VI) to S(-II). At the As(III) concentration range of interest (0.1 to 1 mM), the stability of As(inf2)S(inf3) is highly sensitive to pH and [S(-II)]. Thus, the relative rates at which D. auripigmentum reduces As(V) and S(VI) are critical to its formation of As(inf2)S(inf3). Other As(V)- or S(VI)-reducing bacteria are unable to precipitate As(inf2)S(inf3) either due to their inability to reduce both As(V) and S(VI) or because they reduce S(VI) too rapidly. Electron microscopy of thin sections showed that the precipitate forms both intra- and extracellularly. Microbial As(inf2)S(inf3) formation nucleates precipitation of the mineral in the bulk milieu, whereas heat-killed cells alone do not serve as templates for its formation. Precipitation of As(inf2)S(inf3) by D. auripigmentum suggests that As(inf2)S(inf3) formation may be important in the biogeochemical cycle of arsenic.

Journal Article↗

PubMed1981

Influence of the alternative protein A interaction on the precipitation between human monoclonal immunoglobulins and protein A from Staphylococcus aureus.

A quantitative nephelometric test system was used to evaluate the prerequisites for occurrence of precipitation between human immunoglobulins and protein A from Staphylococcus aureus. Purified human monoclonal IgG, IgA, and IgM with varying expressions of the alternative Fab-related protein A reactivity and F)ab')2 gamma, Fc gamma, and F(ab')2 alpha fragments from the myeloma proteins were tested for their precipitation reaction with protein A and for their ability to induce coprecipitation with protein A and to inhibit the precipitation between human polyclonal IgG and protein A. The results indicate that both the classical Fc gamma and the alternative F(ab')2 epsilon equivalent protein A interactions are needed to obtain precipitation between protein A and IgG. Fc gamma fragments from three IgG myeloma proteins inhibited the precipitation between human polyclonal IgG and protein A in the same way, indicating that the Fc gamma fragment is monovalent in its reaction with protein A. In contrast, polyclonal F(ab')2 alpha fragments precipitated protein A in the presence of nonprecipitating rabbit IgG, suggesting that the alternative protein A reactivity is bivalently expressed in human immunoglobulins.

Animals↗

PubMed1982

Distribution of mitochondrial calcium: pyroantimonate precipitation and atomic absorption spectroscopy.

Mitochondrial function is highly dependent upon the concentrations of cations within the various compartments of this organelle. Utilizing variants of the pyroantimonate precipitation method, we have undertaken to localize cations, particularly calcium, in isolated mitochondria. Precipitated cations were present in two major compartments: 1) within the intracristal space and 2) in the matrix, frequently in association with the matrix face of cristal membranes. Precipitated cations were abundant in mitochondrial samples fixed with most pyroantimonate-containing fixatives, but were usually absent in samples fixed in phosphate-buffered, pyroantimonate-containing fixative solutions. Atomic absorption spectroscopy demonstrated that Ca2+ added to mitochondrial suspensions prior to fixation was retained in the mitochondrial pellet if 0.1 M collidine was present as the fixative buffer. When the same concentration of phosphate-buffered pyroantimonate-osmium fixative was employed, however, much of the added Ca2+ was lost to the supernatant. The suborganellar localization of cations was influenced by the presence of added respiratory substrate. Incubation of mitochondria in an isoosmotic buffered sucrose medium without succinate favored localization of precipitates in the intracristal space of the outer compartment. In the presence of succinate, the localization of precipitates was shifted toward the matrix compartment. This redistribution was particularly obvious in samples to which Ca2+ had been added and was blocked by the addition of antimycin. The observation of precipitated cations in the outer mitochondrial compartment supports previous evidence for a calcium-binding protein in this compartment.

Animals↗

PubMed2005

Proteins of Thermus thermophilus are resistant to glycation-induced protein precipitation: an evolutionary adaptation to life at extreme temperatures?

In thermophilic bacteria, formation of Maillard products may occur at increased rates because this reaction is favored at higher temperatures. Therefore, specific protective mechanisms against glycation-induced protein precipitation are likely to exist in thermophilic bacteria. Indeed, Thermus thermophilus proteins remained soluble when a cell-free extract of T. thermophilus was incubated at 37 degrees C in the presence of glucose, fructose, or methylglyoxal; whereas E. coli proteins precipitated. In E. coli cell-free extracts, sugar-induced precipitation was accelerated by the addition of 5 microM Fe2+ and inhibited by metal chelators, suggesting that glycoxidation processes are involved in the formation of the precipitate. A low lysine content, endogenous small scavenger molecules, or enzymatic "antiglycation" mechanisms for the degradation of AGEs or their precursors could be excluded as possible causes for the resistance to protein precipitation in T. thermophilus. Therefore, the resistance to glycation-mediated protein precipitation is an endogenous property of thermophilic proteins that was acquired during evolution in environments with high glycation activity.

Adaptation, Physiological↗

PubMed2006

Experimental and computer modelling speciation studies of the effect of pH and phosphate on the precipitation of calcium and magnesium salts in urine.

BACKGROUND: pH and phosphate concentration are the major determinants of precipitation in urine of the salts of calcium and magnesium. This study aims to model the process of salt precipitation and establish whether the acidification of urine samples is necessary for the accurate measurement of calcium and magnesium in a clinical laboratory setting. METHODS: Urine samples were collected from 21 patients, aliquots were taken from each patient sample and the pH was adjusted to cover the range 2.0-10.0. The analytical and biological variation for each analyte was established and used to calculate percentage changes and critical differences. The critical difference was used to assess whether there was a significant difference between acidified and un-acidified samples. The JESS (Joint Expert Speciation System) thermodynamic computer-modelling program was used to predict the distribution of salt species formed with varying pH values and phosphate levels in simulated urine. RESULTS: The results showed that at a pH greater than 6.5, measured calcium, magnesium and phosphate significantly decreased as a result of precipitation (p<0.0001), although the critical difference was generally not exceeded. Computer modelling showed that both pH and phosphate concentration affected the distribution of salt species formed, as well as the precipitation patterns of calcium and magnesium phosphates. Overall, calcium phosphate precipitation tends to predominate at lower phosphate concentrations and at pH values below about 6.5, while both calcium and magnesium phosphate precipitation occur at higher phosphate concentrations and pH values greater than 6.5. CONCLUSIONS: For accurate analysis of these analytes in urine, the pH should be routinely measured and acidification should be undertaken prior to analysis if the pH is greater than 6.5. Based on the findings of this study, acidification or the lack of it does not result in a clinically significant change in calcium, magnesium and phosphate measured in urine. This study also predicted the likely salt species formed at varying urinary pH values and phosphate concentrations.

Calcium↗

PubMed1975

Boar seminal zinc-precipitable protein and the haemagglutinin.

About 30% of boar seminal plasma nitrogen is maximally precipitated at room temperature by 6 to 10 mM zinc in citrate solution at pH 8. A rise in the total nitrogen precipitated by 1 to 6 mM zinc is accompanied by a fall in the haemagglutinin titre of the supernatant fluid. At 6 mM zinc addition, 95% of the haemagglutinin is precipitated, but much of this is recoverable by re-solution of the zinc precipitate. Protein profile studies by gel-filtration chromatography of the zinc precipitate solution reveals a mixture of proteins, some of which are not by themselves zinc-precipitable.

Agglutinins↗

PubMed1976

Relationship between precipitate volume and antigen weight in immunodiffusion.

Immunodiffusion of antigen from conic and cylindrical wells of various sizes in thick antiserum gel plate was studied. The shape of precipitate was affected by the shape and size of the well and by the antigen weight. In the test of anti-rabbit serum agar plate, albumin concentration ranged from 2 to 25 mg/ml, and the maximal albumin weight was 15.8 times the minimal one. In this case, regression line and standard deviation (S.D.) were calculated from antigen weight (x) and standardized data (y1) of precipitate volume, and from antigen weight and standardized data (y2) of precipitation ring area, and the following results were obtained: y1=0.006x-1.611, S.D.=0.092 for the former and y2=0.005x-1.546, S.D.=0.295, for the latter. In the test of agar plates containing anti-carbonic anhydrase B (CA B), the maximal concentration and weight of CA B was 16.7 times and 18.3 times the minimal one, respectively. In this case, regression line and standard deviation obtained from the CA B weight (x) and the standardized data (y3) of the precipitate volume, and from the weight (x) and the standardized data (y4) of the precipitation ring area were as follows: y3=0.146x-1.754, S.D.=0.208, and y4=0.104x-1.251, S.D.=0.717, respectively. There was a clearer linearity in the relationship between the precipitate volume and the antigen weight than in that between the ring area and the antigen weight. In the gel medium, antigen concentration gave no influences on antigen quantitation at the end point of antigen diffusion in a wide range.

Albumins↗

PubMed2001

The association between extreme precipitation and waterborne disease outbreaks in the United States, 1948-1994.

OBJECTIVES: Rainfall and runoff have been implicated in site-specific waterborne disease outbreaks. Because upward trends in heavy precipitation in the United States are projected to increase with climate change, this study sought to quantify the relationship between precipitation and disease outbreaks. METHODS: The US Environmental Protection Agency waterborne disease database, totaling 548 reported outbreaks from 1948 through 1994, and precipitation data of the National Climatic Data Center were used to analyze the relationship between precipitation and waterborne diseases. Analyses were at the watershed level, stratified by groundwater and surface water contamination and controlled for effects due to season and hydrologic region. A Monte Carlo version of the Fisher exact test was used to test for statistical significance. RESULTS: Fifty-one percent of waterborne disease outbreaks were preceded by precipitation events above the 90th percentile (P = .002), and 68% by events above the 80th percentile (P = .001). Outbreaks due to surface water contamination showed the strongest association with extreme precipitation during the month of the outbreak; a 2-month lag applied to groundwater contamination events. CONCLUSIONS: The statistically significant association found between rainfall and disease in the United States is important for water managers, public health officials, and risk assessors of future climate change.

Animals↗

PubMed1979

Waldenström's macroglobulinemia associated with a mixed cryoglobulin. Report of a case with partial precipitation in vitro at 37 degrees C.

A 68-year-old man had Waldenström's macroglobulinemia associated with a mixed cryoglobulin (monoclonal IgM kappa and polyclonal IgG, 0.96 g/dL) manifested by purpura, weight loss, hepatosplenomegaly, and proteinuria. On cooling of serum warmed to 50 degrees C, the cryoglobulin begins to precipitate above 40 degrees C, with substantial precipitation at body temperature. Incubation at 37 degrees C (after equilibration at 50 degrees C) causes approximately two thirds of the cryoglobulin to precipitate in 30 to 60 minutes; the precipitate dissolves on rewarming the serum to 50 degrees C. The ability of this cryoglobulin to precipitate at 37 degrees C in vitro indicates that the temperature spectrum of cyroglobulin precipitation can extend to body temperature or above it, and suggests that some serum samples that contain cryoglubulins must be separated quickly at a temperature of 37 degrees C or higher.

Aged↗

PubMed2001

Opioid and cannabinoid modulation of precipitated withdrawal in delta(9)-tetrahydrocannabinol and morphine-dependent mice.

The goal of the present study was to elucidate the relationship between cannabinoid and opioid systems in drug dependence. The CB(1) cannabinoid receptor antagonist SR 141716A precipitated both paw tremors and head shakes in four different mouse strains that were treated repeatedly with Delta(9)-tetrahydrocannabinol (Delta(9)-THC). SR 141716A-precipitated Delta(9)-THC withdrawal was ameliorated in mu-opioid receptor knockout mice compared with the wild-type control animals and failed to occur in mice devoid of CB(1) cannabinoid receptors. An acute injection of morphine in Delta(9)-THC-dependent mice undergoing SR 1417161A-precipitated withdrawal dose dependently decreased both paw tremors, antagonist dose 50 (AD(50)) (95% CL) = 0.035 (0.03--0.04), and head shakes, AD(50) (95% CL) = 0.07 (0.04--0.12). In morphine-dependent mice, the opioid antagonist naloxone precipitated head shakes, paw tremors, diarrhea, and jumping. As previously reported, naloxone-precipitated morphine withdrawal failed to occur in mu-opioid knockout mice and was significantly decreased in CB(1) cannabinoid receptor knockout mice. Acute treatment of Delta(9)-THC in morphine-dependent mice undergoing naloxone-precipitated withdrawal blocked paw tremors, AD(50) (95% CL) = 0.5 (0.3--1.0), and head shakes AD(50) (95% CL) = 0.6 (0.57--0.74) in dose-dependent manners, but failed to diminish the occurrence of diarrhea or jumping. Finally, naloxone and SR 141716A failed to elicit any overt effects in Delta(9)-THC-dependent and morphine-dependent mice, respectively. These findings taken together indicate that the mu-opioid receptor plays a modulatory role in cannabinoid dependence, thus implicating a reciprocal relationship between the cannabinoid and opioid systems in dependence.

Animals↗

PubMed2001

The nucleoside triphosphate pyrophosphohydrolase isozyme PC-1 directly promotes cartilage calcification through chondrocyte apoptosis and increased calcium precipitation by mineralizing vesicles.

OBJECTIVE: Aging associated elevations of cartilage extracellular inorganic pyrophosphate (PPi) and PPi-generating nucleoside triphosphate pyrophosphohydrolase (NTPPPH) are linked with degenerative arthritis in chondrocalcinosis. Increased chondrocyte apoptosis and expression of annexin V occur at sites of matrix calcification in degenerative arthritis, and membrane limited chondrocyte apoptotic bodies containing NTPPPH may promote chondrocalcinosis by acting as mineralizing matrix vesicles (MV). Because chondrocytes express 3 related NTPPPH isozymes [PC-1, autotaxin (ATX), and B10/PDNP3], we evaluated the effects on apoptosis and MV mediated calcium precipitation of direct expression of NTPPPH isozymes. METHODS: To achieve "gain of function" of NTPPPH isozymes, we expressed the isozymes in cultured chondrocytic cells. RESULTS: Plasmid cDNA transfection of PC-1, but not ATX or B10/PDNP3, markedly increased apoptosis of cultured chondrocytic knee meniscal cells and increased calcium precipitation by MV fractions. The capacity of PC-1 to increase chondrocyte and meniscal cell apoptosis, and calcium precipitation by MV, further analyzed using adenoviral gene transfer in cultured meniscal cells and articular chondrocytes, was shown to be dependent on integrity of the PC-I NTPPPH catalytic site. The MV-containing fraction released from meniscal cells and chondrocytes that overexpressed wild-type PC-1 had increased annexin V. Use of antibodies to annexin V and PC-1 revealed that both annexin V and PC-1 directly mediated the elevated calcium-precipitating capacity of MV. The increased ability of MV to precipitate calcium from PC-1-overexpressing cells did not require exogenous ATP. CONCLUSION: Upregulated expression of enzymatically active PC-1 directly promotes apoptosis, increased MV annexin V, and an increased capacity of meniscal cell and articular chondrocyte MV to precipitate calcium. These results suggest a direct link between increased PC-1 expression and the pathogenesis of chondrocalcinosis.

Apoptosis↗

PubMed2004

Effect of atmospheric precipitation on the dissolved loads of the Dongjiang River, China.

The atmospheric precipitation plays an important role in influencing the river chemistry of the Dongjiang River. The atmospheric contribution to river water is estimated by reference to Cl concentration called Clref. The Clref of 41.97 micromol/L represents the highest chloride concentration of the rainwater inputs to river water, thus sea salts are responsible for total Cl concentration of the Dongjiang River. According to the principal compositions of precipitation and river water, two approaches-sea salt correction and precipitation correction were proposed in order to correct the contribution proportions of atmospheric precipitation on the solutes and to calculate chemical weathering rate. The results reflected that the atmospheric contribution ratios fluctuate from approximately 5% to approximately 20% of TDS (total dissolved solids) in the Dongjiang River. As compared with the other world watersheds, the lower dissolved ion contents and high runoff may result in the obvious influence of precipitation on river chemistry in the Dongjiang basin. The major elemental chemistry is mainly controlled by silicate weathering, with the anion HCO3- and cation Ca2+ and Na+ dominating the major compositions in this basin. The estimated chemical weathering rate of 15.78-23.48 t/(km2 x a) is only 40%-60% of a global average in the Dongjiang basin. Certainly, the estimated results are still under correction gradually because the effect of human activities on the precipitation chemistry has never been quantified in detail.

China↗

PubMed2005

[Activation of the spinal extracellular signal-regulated kinase is involved in morphine dependence and naloxone-precipitated withdrawal response].

Extracellular signal-regulated kinase (ERK), a mitogen-activated protein kinase (MAPK), transduces a broad range of extracellular stimuli into diverse intracellular responses. It has been reported that ERK is involved in the modulation of nociceptive information and central sensitization produced by intense noxious stimuli or peripheral tissue inflammation. Our previous studies showed that the spinal neurons sensitization was involved in morphine withdrawal response. This study was to investigate the role of the spinal ERK in morphine dependence and naloxone-precipitated withdrawal response. To set up morphine-dependent model, rats were subcutaneously injected with morphine (twice a day, for 5 d). The dose of morphine was 10 mg/kg on the first day and was increased by 10 mg/kg each day. On day 6, 4 h after the injection of morphine (50 mg/kg), morphine withdrawal syndrome was precipitated by an injection of naloxone (4 mg/kg, i.p.). Using anti-phospho-ERK (pERK) antibody, the time course of pERK expression was detected by Western blot. U0126, a mitogen-activated protein kinase kinase (MEK) inhibitor, or phosphorothioate-modified antisense oligonucleotides (ODN) was intrathecally injected 30 min or 36, 24 and 12 h before naloxone-precipitated withdrawal. The scores of morphine withdrawal symptom and morphine withdrawal-induced allodynia were observed. One hour after naloxone-precipitated withdrawal, pERK expression in the spinal dorsal horn was assessed by immunohistochemical analysis and Western blot was used to detect the expression of cytosolic and nuclear fraction of pERK in the rat spinal cord. The results showed that the expression of cytosolic and nuclear fraction of pERK, not non-phospho-ERK, in the spinal cord was gradually increased following the injection of morphine. When morphine withdrawal was precipitated with naloxone, the expression of the spinal pERK further increased. Intrathecal administration of U0126 or antisense ODN against ERK decreased the scores of morphine withdrawal, attenuated morphine withdrawal-induced allodynia and also inhibited the increase of pERK expression in the spinal cord of morphine withdrawal rats. These results suggest that activation of the spinal ERK is involved in morphine-dependent and naloxone-precipitated withdrawal response.

Animals↗

PubMed1991

[Oral streptococci affecting Ca-phosphate precipitation].

The precipitation of Ca-compounds in ageing dental plaque leads to the formation of calculus. Bacterial lipoteichoic acid (LTA) has been discussed as Ca-carrier in this process (Zoon et al., 1989). Therefore in this study, LTA was isolated from oral streptococci and tested for its influence on the precipitation of Ca-phosphate. LTA-containing bacteria, LTA-free bacteria and isolated LTA were added to the reaction mixtures for Ca-phosphate precipitation and the amount of precipitated mineral was measured. LTA-containing cells and, above all, LTA, inhibited Ca-phosphate precipitation in a distinct pH-range just above the acid solubility of the mineral by complexing Ca(2+)-ions. Experiments with Ca-fluoride in place of Ca-phosphate showed that LTA did not affect the precipitation of this mineral.

Calcium Fluoride↗

PubMed1990

Insufficient accuracy and specificity of polyanion precipitation methods for quantifying low-density lipoproteins.

Recently, polyanion precipitation assays for low-density lipoprotein (LDL)-cholesterol have been found to underestimate their analyte in normolipidemic samples (Siekmeier et al., Clin Chim Acta 1988;177:221-30). Therefore, accuracy, specificity, and interference by nonesterified fatty acids have been studied for three precipitants (obtained by heparin, dextran sulfate, or polyvinyl sulfate precipitation). At normal concentrations of LDL, precipitation is incomplete, whereas it is nearly quantitative at high concentrations of LDL. The polyvinyl sulfate reagent markedly responds to variations in the amount of non-LDL protein present in the precipitation mixture. In the dextran sulfate and the polyvinyl sulfate method, but not in the heparin method, the percentages of LDL precipitated notably increase as the concentration of the polyanion compound is decreased. In either assay, very-low-density lipoproteins, but not high-density lipoproteins, are significantly coprecipitated (dextran sulfate 28%, polyvinyl sulfate and heparin 66%) in a concentration-independent fashion. Increased concentrations of nonesterified fatty acids markedly interfere with the dextran sulfate and polyvinyl sulfate assay, but do not much affect results with the heparin reagent.

Adult↗

PubMedDate not supplied

pH adjustment of local anesthetic solutions with sodium bicarbonate: laboratory evaluation of alkalinization and precipitation.

pH adjustment of several commonly administered local anesthetic solutions was evaluated in the laboratory. The pH achieved after the addition of sodium bicarbonate and the onset of precipitation for alkalinized solutions were recorded. Solutions of 2-chloroprocaine and lidocaine readily alkalinized to near physiological pH without precipitation. Mepivacaine solutions exhibited a tendency for delayed precipitation (18-20-minute latency for 1.5% mepivacaine) above neutral pH. Bupivacaine and etidocaine solutions precipitated after the addition of small amounts of sodium bicarbonate and could not be alkalinized to physiologic pH. Two commercially available sodium bicarbonate preparations, 4% (wt/vol) and 8.4% (wt/vol), were compared and produced similar pH changes and precipitation behavior. The data obtained for pH and time to precipitation for local anesthetic solutions alkalinized with sodium bicarbonate may be useful for practical application in the clinical setting.

Anesthetics, Local↗