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At least 865 records · Page 48Linked to original sources
PubMed1986

Identification and selective precipitation of human aldehyde dehydrogenase isozymes using antibodies raised to horse liver aldehyde dehydrogenase isozymes.

Aldehyde dehydrogenase (ALDH) enzymes from human liver homogenates were recognized in immunoblotting experiments and precipitated in Ouchterlony double diffusion gels by antibodies raised to the horse liver mitochondrial and cytosolic ALDH isozymes. The antibody raised to the cytosolic horse liver ALDH (alpha HC) has been shown to be specific for cytosolic ALDH isozymes, while the antibody raised to the horse liver mitochondrial ALDH (alpha HM) precipitated both mitochondrial and cytosolic ALDH isozymes. It was possible to selectively remove the cytosolic ALDH from a homogenate of a liver sample from a Caucasian by preincubation with alpha HC; the remaining mitochondrial enzyme was then precipitated by alpha HM in double diffusion gels. The experiments were repeated with a liver sample from an Oriental, presumed to have been alcohol sensitive since no active mitochondrial ALDH was found. The precipitation of a relatively inactive mitochondrial enzyme by alpha HM from a cytosolic ALDH-free sample confirmed previous reports of the existence of a mitochondrial ALDH in tissue from an alcohol-sensitive Oriental. The results of immunoblotting experiments confirm the co-migration, in electrophoresis, of the cytosolic and mitochondrial ALDHs from the liver of an alcohol-sensitive Oriental. The results reported here, together with previous observations, indicate that the antibodies raised to horse liver ALDH isozymes can be used to determine the subcellular location of ALDH isozymes in various human tissues, including frozen tissue samples which are not amenable to subcellular fractionation.

Aldehyde Dehydrogenase↗
PubMed1989

Evoked and psychogenic epileptic seizures. I. Precipitation.

The precipitation of seizures by external stimulation (evoked seizures) is well known. Less well known is the precipitation of seizures by a change in the patient's thinking or feelings. This artick uses Lockhart's monkey model of focal epilepsy to propose that there is a close relationship between seizures and ongoing brain activity. Thus, seizures precipitated by both voluntary and spontaneous changes in behaviour and thinking must commonly occur. Clinical examples of such seizure precipitation is described.

Adult↗
PubMed1984

A general theory for the precipitin reaction--based on Fc-mediated precipitation.

Fc-mediated immune precipitation is studied theoretically by computer simulation of precipitin curves and of zonal profiles of soluble immune complexes. Comparison with experiments indicates that Fc-mediated immune precipitation is caused by Fc-Fc interactions with association constants ranging from 10(5) to 10(7) liters/mole. The Langmuir adsorption isotherm is used for evaluation of these interactions. A general theory for the precipitin reaction is formulated, assuming it to be a three-stage process: 1st stage Formation of immune complexes, 2nd stage Precipitation due to coalescence of antibody-rich immune complexes, and 3rd stage Fc-mediated immune precipitation.

Antigen-Antibody Complex↗
PubMedDate not supplied

Characterization of iron and manganese precipitates from an in situ ground water treatment plant.

Aquifer samples from the precipitation zone of an in situ iron and manganese removal plant that was operated for 10 years were analyzed for iron and manganese minerals. Measurements were performed by various chemical extraction techniques (5 M HCI, 0.008 M Ti(III)-EDTA, 0.114 M ascorbic acid), X-ray diffraction and Mössbauer spectroscopy. Chemical extractions showed that iron was precipitated as ferric oxides, whereas manganese was not oxidized but deposited as Mn(II) probably within carbonates. The ferric oxides in particular accumulate preferentially in the smaller grain- size fractions. This tendency was observed to a lesser extent for manganese. X-ray diffraction and Mössbauer spectroscopy showed that the ferric oxides were mainly crystalline (goethite, 50% to 100% of the iron). Ferrihydrite was found as well, but only as a minor fraction (< or = 12%). Pure manganese minerals were not found by X-ray diffraction. The precipitated amounts of iron (5 to 27 micromol/g Fe as ferric oxide) and manganese (1 to 4 micromol/g Mn) during 10 years operation of the treatment plant agree with values that were estimated from operational parameters (9 to 31 micromol/g Fe and 3 to 6 micromol/g Mn). Considering the small amounts of precipitated iron and manganese, no long-term risks of clogging of the aquifer are expected.

Iron↗
PubMed1996

Blood precipitate associated with intra-abdominal carboxymethylcellulose administration.

A precipitate was observed on the blood films of horses (15 of 16) and one cow given a peritoneal infusion of 1 % sodium carboxymethylcellulose (SCMC) solution to prevent abdominal adhesions. The intensity of the precipitate seen 2 to 3 days post-infusion strongly correlated with the administered dose of SCMC (range 0.96 to 11.7 ml/kg). The dose given was inversely correlated with bodyweight and the most prominent precipitates were seen in foals. The precipitate was observed as early as 24 hours and persisted for as long as 9 days after SCMC administration. Fibrinogen was the only hematological or biochemical parameter consistently abnormal in horses receiving SCMC, mild increases (500 to 700 mg/dl) were noted in 11/16 cases but did not correlate with SCMC administration.

Journal Article↗
PubMed1968

Lectins in extracts of certain Polygonaceae seed precipitate animal and human serums.

Seeds of four species of Polygonaceae were tested for lectins that precipitate human and animal serums. Rumex crispus, Polygonum convolvulus, and Polygonum pennsylvanicum developed specific precipitate bands on double diffusion on agar gel plates. These bands were enhanced and increased in number when extracts were tested against serums from patients with certain diseases. When tested against lyophilized serum, no precipitate bands developed. The active substance cannot be dialyzed through cellulose membrane against running tap water for 16 hours, and it is heat stable. Extracts from Fagopyrum esculentum developed no precipitate bands.

ABO Blood-Group System↗
PubMed1982

Iron Oxidation and Precipitation of Ferric Hydroxysulfates by Resting Thiobacillus ferrooxidans Cells.

The oxidation of ferrous ions, in acid solution, by resting suspensions of Thiobacillus ferrooxidans produced sediments consisting of crystalline jarosites, amorphous ferric hydroxysulfates, or both. These products differed conspicuously in chemical composition and infrared spectra from precipitates formed by abiotic oxidation under similar conditions. The amorphous sediments, produced by bacterial oxidation, exhibited a distinctive fibroporous microstructure when examined by scanning electron microscopy. Infrared spectra indicated outer-sphere coordination of Fe(III) by sulfate ions, as well as inner-sphere coordination by water molecules and bridging hydroxo groups. In the presence of excess sulfate and appropriate monovalent cations, jarosites, instead of amorphous ferric hydroxysulfates, precipitated from bacterially oxidized iron solutions. It is proposed that the jarositic precipitates result from the conversion of outer-sphere (T(d)) sulfate, present in a soluble polymeric Fe(III) complex, to inner-sphere (C(3v)) bridging sulfate. The amorphous precipitates result from the further polymerization of hydroxo-linked iron octahedra and charge stabilized aggregation of the resulting iron complexes in solution. This view was supported by observations that bacterially oxidized iron solutions gave rise to either amorphous or jarositic sediments in response to ionic environments imposed after oxidation had been completed and the bacteria had been removed by filtration.

Journal Article↗
PubMed1966

Detoxification and immunogenic properties of endotoxin-containing precipitate of Brucella abortus.

Badakhsh, Fred F. (University of Georgia, Athens), and John W. Foster. Detoxification and immunogenic properties of endotoxin-containing precipitate of Brucella abortus. J. Bacteriol. 91:494-498. 1966.-Endotoxin-containing precipitates (ECP) were prepared from Brucella abortus strain 19A by aqueous ether extraction followed by ethyl alcohol precipitation. Lysozyme was the most effective of several enzymes tried for detoxification of endotoxin present in the precipitate. Trypsin was shown to reduce mouse lethal toxicity but not rabbit dermal toxicity. Immunological studies of ECP and enzyme-treated ECP demonstrated that lysozyme did not harm the immunogenic property of ECP, whereas heat, ribonuclease, lipase, and proteolytic enzymes had an adverse effect. Serological reactivity of ECP was increased after lysozyme treatment, whereas ribonuclease reduced serological activity.

Animals↗
PubMed1985

Study of precipitation reactions to Actinomyces israelii antigens in uterine secretions.

Uterine secretions were obtained from 110 women and analysed by counterimmunoelectrophoresis for the occurrence of precipitation reactions against Actinomyces israelii antigens. Precipitation reactions were found in secretions from seven women and a correlation was found between these reactions and long term use of plastic intrauterine devices. The precipitating components could not be proved to be immunoglobulins; neither could identity be shown with IgG precipitins in reference serum. The nature and the importance of the precipitating components are discussed.

Actinomyces↗
PubMedDate not supplied

Predisposing and precipitating factors for delirium in hospitalized older patients.

Delirium is a common and serious problem for older hospitalized patients. This investigation proposes a multifactorial model of delirium etiology, involving a complex interrelationship of predisposing (vulnerability) factors and precipitating factors (acute insults). An overview of risk factors for delirium identified in 14 studies published since 1980 is provided. Although these studies identify key risk factors for delirium, they do not allow the examination of the interrelationship of predisposing and precipitating factors. Thus, we present two prospective cohort studies by our group which empirically examine: (1) predisposing (vulnerability) factors, (2) precipitating factors, and (3) the interrelationship of predisposing and precipitating factors. Understanding these risk factors is the key to developing appropriate preventive strategies and to target intermediate and high risk patients for intervention efforts.

Aged↗
PubMed1999

Upper extremity vein thrombosis: etiologic categories, precipitating causes, and management.

Although an increasing incidence of upper extremity venous thrombosis (U/E-DVT) has been reported, a relative paucity of information regarding the etiologic categories, precipitating causes, and proper management for this disorder is available. To settle on a strategy for the management of U/E-DVT, retrospective analyses were performed using records from the authors' hospital. In 12 patients (seven men, five women), 61 (mean) years of age, diagnosed as having symptomatic venography-proved U/E-DVT and followed up for 41 (mean) months, etiologic factors, precipitating causes, treatments, and outcomes were retrospectively analyzed. As etiologic factors, five of the patients had neoplastic disease, one had hemodialysis, and two had transvenous pacemaker implantations. Among various precipitating causes of U/E-DVT, hypoproteinemia was most frequently noted (67%). Various types of therapeutic management were selected: from thrombolysis with urokinase in six, balloon angioplasty in two, thrombectomy in two, and venous bypass surgery in one patient. Pulmonary embolism did not occur in any of the patients and only three of them complained of mild intermittent arm swelling during the follow-up period. Four patients died of neoplastic disease or heart failure (three within the first 6 months). This study, though limited, suggests that the rate of mortality depends on multiple underlying medical problems in U/E-DVT patients. Low incidences of late postthrombotic sequelae and pulmonary embolism were noted in this series. Symptomatic U/E-DVT patients could be managed conservatively with a revised supplementary therapy for their precipitating causes of U/E-DVT.

Adult↗
PubMedDate not supplied

Lesions and identification of crystalline precipitates of glycoprotein IIb-IIIa antagonists in the rat kidney.

Two glycoprotein IIb-IIIa antagonists (xemilofiban, SC-54684A, and orbofiban, SC-57099B), which are platelet aggregation inhibitors, caused crystalline precipitates in the kidney tubules of rats at high dosages. Dogs were not affected. Depending on the degree of the precipitation, which was dosage dependent, and the location, which differed somewhat between the two compounds, the lesions varied from acute obstruction with tubule cell necrosis, nephron dilation, and sudden death with no inflammation to severe chronic pyogranulomatous inflammation. In order to understand the relevance of the lesions, it was important to identify the precipitates. This was technically challenging because the crystals were water soluble (dissolving in routine fixing and staining techniques) and were present in insufficient quantity to physically isolate. Techniques were devised to evaluate the crystals in situ in unstained frozen sections prepared without directly embedding the tissues in supporting medium, which interfered with the analyses. The crystals were analyzed in situ by infrared and Raman spectroscopy and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). Uroliths found in the renal pelvis of one animal were analyzed by liquid chromatography/mass spectrometry. The resulting spectra showed that the crystals were the de-esterified acids of the parent compounds. This knowledge allowed us to predict that the crystalline precipitates would not be a hazard to humans because of the large multiples of the human dosage at which they occurred and because of differences in renal physiology between rats, dogs, and humans.

Alanine↗
PubMed1987

Localization of calcium in roots and microsomal membranes of corn by direct pyroantimonate precipitation.

Many cell membrane systems, including microsomal vesicles of corn, are able to regulate calcium levels both in vivo and in vitro, often in an ATP-dependent, calmodulin-stimulated fashion. The purpose of this study was to determine calcium distribution in meristematic cells of intact tissue and microsomal vesicles from corn roots using direct pyroantimonate-osmium fixation. In root cells, precipitates were localized in mitochondria, plastids, the nucleus, endoplasmic reticulum, Golgi apparatus, and along the plasma membrane. Plasma membrane-enriched microsomal vesicles isolated from corn roots incubated in media to permit calcium transport before pyroantimonate-osmium fixation show internal precipitates associated with the membrane and in the lumen of the vesicles. De-staining of the sections with 1 mM EDTA or EGTA removed precipitate from the sections, confirming the presence of calcium in the antimonate precipitates. These data support biochemical data that this same membrane preparation exhibited ATP-dependent calcium sequestration that was stimulated by calmodulin, as measured by retention of 45Ca. This provides evidence that these membranes are responsible for ATP-requiring, calmodulin-stimulated calcium transport in the intact cell.

Antimony↗
PubMed2001

[Involvement of glial glutamate transporters in morphine dependence and naloxone-precipitated withdrawal].

A body of evidence supports that excitatory amino acid systems, particularly glutamatergic one, participate in morphine dependence and naloxone-precipitated withdrawal. In this study, we examined the involvement of glial glutamate transporters, GLT-1 and GLAST, in them. Rats were rendered morphine-dependent by subcutaneous implantation of two 75 mg morphine pellets for 5 days. Intracerebroventricular administration of DL-threo-beta-benzyloxyaspartate, a glutamate transporter inhibitor significantly facilitated various naloxone-precipitated withdrawal signs. By northern blot analysis, the expression of GLT-1 mRNA was found to decrease significantly in the striatum and thalamus of morphine-dependent rats, and to increase significantly in the striatum 2 hr after the naloxone-precipitated withdrawal. On the other hand, there were no significant changes in GLAST mRNA levels in any brain regions. In vivo microdialysis experiments revealed that the extracellular glutamate levels was elevated in the striatum and nucleus accumbens, in which the changes of GLT-1 mRNA level were observed, during naloxone-precipitated morphine withdrawal. In cultured astrocytes, the expression of GLT-1 mRNA was regulated by agents activating the cAMP pathway, as well as beta-adrenergic agonist and dopamine, but not morphine. These results suggest that the changes of GLT-1 expression, which alter the glutamate uptake and affect the glutamatergic transmission efficiency, play a role in the development of morphine dependence and the expression of morphine withdrawal.

Amino Acid Transport System X-AG↗
PubMed2003

Determination of precipitating events in the suicide of psychiatric patients.

Data from therapists who were treating patients when they killed themselves were used to provide information about precipitating events that was missing from accounts obtained from suicide victims' relatives and friends. Among 26 patient suicides studied, the therapists identified a precipitating event in 25 cases; in 19 of these, supporting evidence linked the identified event to the suicide. A schema was developed that identifies nine types of evidence provided by therapists in determining that an event precipitated the suicide. Use of the schema is likely to improve accurate identification of events that precipitate patient suicides, and distinguish them from unrelated coterminous events or suicide risk factors.

Adolescent↗
PubMed1998

Precipitated immune complexes of IgM induce the generation of reactive oxygen species by rabbit polymorphonuclear leucocytes.

We report that immune complexes of IgM (ICIgM) antibodies and ovalbumin in the form of a precipitate from the equivalence zone induce the generation of reactive oxygen species by rabbit blood polymorphonuclear leucocytes (PMN), as measured by the chemiluminescence (CL) production in the presence of luminol. The kinetics of CL generation induced by ICIgM is quite different from that induced by precipitated immune complexes of IgG (ICIgG): the maximum rate of CL production for ICIgM occurs around 14 min, whereas for ICIgG it occurs about 5 min after incubation with the cells. Also the triggering of the process requires a higher concentration of ICIgM than of ICIgG. Evidence is presented that these effects are not mediated by interaction of the antigen (ovalbumin) with the cell, since immune precipitates of ovalbumin and the F(ab')2 fragment had no effect. Our observations that precipitated ICIgM can also be an effective stimulus for CL generation and thus for O2- production reveal a new functional capability of PMN. These results may have implications for the understanding of the participation of ICIgM (as well as of ICIgG) in inflammatory reactions mediated by PMN in immune complex diseases, and in the mechanisms of defense against microbes and other non-self agents.

Animals↗
PubMed1993

Crystal precipitation on dentin by poly(acrylic acid) solutions containing SO4(2-) ions.

The ability of four different 40% poly(acrylic acid) (PAA) solutions, containing 4 or 6 wt-% of either Na2SO4 or (NH4)2SO4, to cause precipitation of CaSO4 on dentin surfaces was investigated. Each treatment consisted of exposing the dentin to one of the four solutions for either 1 or 2 min and was followed by a water rinse (1 min) and air drying (30 sec). The treated dentin surfaces were then evaluated in a scanning electron microscope (SEM), which showed that crystals precipitated on the dentin with these solutions. Of the four investigated PAAs, one performed better than the others with regard to crystal precipitation and blockage of the tubules. This solution was selected for additional studies of the effects of different PAA concentrations (10%, 20%, 30%, 40%, and 50%). In these solutions, 4 and 6 wt-% of either Na2SO4 or (NH4)2SO4 were dissolved. Additional dentin surfaces were then treated with these solutions as described earlier and evaluated in an SEM. This evaluation showed that solutions containing 30-50% PAA resulted in optimized crystal formation for all the different sulfate solutions and that the optimization occurred within 1 min. Besides optimizing crystal precipitation, these mixtures also minimized the frequency of open dentinal tubules.

Acid Etching, Dental↗
PubMed2001

Characterization of casein micelle precipitation by chitosans.

We have found that the addition of chitosan, a cationic polymer, on whole or skim milk produces destabilization and coagulation of casein micelles that takes place without changes in the milk pH or the stability of most whey proteins. The amount of lipids recovered in the chitosan-casein aggregates was similar or higher than that obtained with rennet or acid precipitation. Approximately 70% of milk Ca2+ (approximately 750 mg/L) was found in the chitosan-induced aggregates, which is 10 and 50% higher than the amounts observed with acid or rennet coagulations, respectively. Purified alpha, beta-, and kappa-caseins were extensively precipitated by different molecular weight chitosans at pH 6.8. The phosphate groups of caseins seem not to be relevant in this interaction because dephosphorylated alpha- and beta-caseins were equally precipitated with chitosans. Analysis by optical microscopy of the chitosan-casein complex reveals that the size of the aggregates increase as the molecular weight of chitosans increase. Hydrophobic and electrostatic interactions particpate in the association and coagulation of casein micelles with chitosans of different molecular weights. The phenomenon is observed over a broad range of temperature (4 to 70 degrees C) with a reduction in the concentration of chitosan needed to precipitate the caseins that parallels a reduction in the viscosity of the chitosan solutions. Taken together, the results indicate that the electrostatic interactions may contribute energetically to the association between the two biopolymers, but the hydrophobicity of the complex would be the key determinant in the overall energetics of the reaction.

Animals↗