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At least 1,333 records · Page 74Linked to original sources
PubMed1979

Fc-mediated immune precipitation. I. A new role of the Fc-portion of IgG.

By comparing the amounts of precipitate formed by the reaction between human serum albumin (HSA) and isomolar solutions of rabbit anti-HSA F(ab')2 fragments and of the corresponding intact rabbit anti-HSA IgG, respectively, it was found that the Fc portion of IgG was of great importance for the precipitin reaction. In the present antigen-antibody system, about half of the antigen was precipitated by this mechanism. This effect was called Fc-mediated precipitation and was most clearly expressed in the biologically important zone of low antigen excess and the zone of equivalence. It was found that the pepsin digestion did not change the ability of the F(ab')2 fragments to bind the antigen in comparison to intact IgG. Furthermore, turbidimetric analyses indicated that the Fc portion was involved in the overall mechanism of the precipitin reaction throughout the range of the precipitin curve.

Animals↗
PubMed1984

Precipitating antibodies to nuclear antigens in systemic vasculitis.

We have examined sera from 61 patients with systemic vasculitis for precipitating antibodies to components of saline tissue extracts. Precipitins were rare in patients with polyarteritis nodosa (PAN) and their absence helped to distinguish PAN from vasculitis associated with other connective tissue diseases. Precipitins were detected in some patients with other vasculitides. Previously described precipitating antibodies (anti-Ro [SSA] and anti-La [SSB]) were restricted to a few patients with features of systemic lupus erythematosus (SLE). A different, as yet unidentified, precipitin which reacted with a component of rabbit thymus extract but not calf thymus or human spleen extracts was detected in many patients with rheumatoid disease. This precipitin was present in all patients with active rheumatoid vasculitis (RV) as well as 52% of patients with uncomplicated but active rheumatoid synovitis. Higher titres of precipitating antibody were present in patients with active RV than those with inactive RV or uncomplicated rheumatoid synovitis, and serial studies showed a good correlation between a fall in antibody titre and healing of vasculitis with treatment. These studies suggest that this unidentified precipitin may be an important marker of RV.

Antigens↗
PubMed1982

A "liver" antigen associated with avian erythroblastosis: binding by bentonite and precipitation with sodium dodecyl sulphate.

The properties of a complement fixing antigen, EbAg, extracted from erythroblastosis-affected chicken livers are described. The antigen in extracts freed of structural protein is strongly bound by bentonite, but not by barium sulphate. Strongly alkaline solutions of sodium dodecyl sulphate are required to release the antigen from bentonite. Acidification of the detergent solution precipitates the active solution precipitates the active protein. Extraction of heme from the acidified detergent precipitate by methyl-ethyl ketone further purifies the antigen. This acid detergent treatment eliminates the need to use bentonite as a purification step.

Adsorption↗
PubMed1984

Precipitating autoantibodies to mitochondrial proteins in progressive systemic sclerosis.

Sera from 88 patients with progressive systemic sclerosis were examined for precipitating mitochondrial antibodies using sonicated rat liver mitochondrial fraction as an antigen source in immunodiffusion. Precipitin lines indicating the presence of anti-mitochondrial antibodies (AMA) in 22 patients were detected. Only six of 22 sera had, additionally, precipitating antibodies to nuclear antigens. Standardized reference sera containing antibodies to mitochondrial antigens (M-A, M-B and M-C systems) were used to further characterize the type of mitochondrial antibodies. M-B antibody was most commonly detected (72.7%) either alone (eight patients) or in combination (eight patients) with M-A and M-C antibodies. M-A antibody was found in 12 patients (54.5%) and M-C antibody was present in three. The antigen related to M-B is DNAase and trypsin sensitive, in contrast to the resistant M-A antigen. AMA were detected in 21 of 22 patients by indirect immunofluorescence. When solid phase ELISA was used to detect AMA using mitochondrial fraction as antigen, a significant difference (P less than 0.005) was noted between sera with and without precipitating mitochondrial antibody. The antibody was frequently present in patients with progressive systemic sclerosis detected 2 or more years earlier (P less than 0.01). Three patients were found to have primary biliary cirrhosis and others had pruritus, hepatomegaly or abnormal liver function tests. The implication of the findings is discussed.

Animals↗
PubMed1984

Acute severe asthma. A prospective study of the precipitating factors in 40 children.

A prospective study was undertaken to determine the factors precipitating acute severe asthma in children attending the Red Cross War Memorial Children's Hospital, Cape Town. A comparison in terms of recent exposure to possible precipitating factors was made between 40 known asthmatics presenting with acute severe asthma and 40 known asthmatics who were clinically well. Exposure to known allergens had occurred in 7 cases. The time of onset of symptoms bore no relationship to meteorological changes in temperature, humidity or average pressure. Drug compliance in both groups was of the order of 50%. The majority of severe asthma attacks were associated with infection of the respiratory tract. The importance of infection as a precipitating factor in a severe asthma attack is discussed with reference to the cholinergic, adrenergic and immunological mechanisms.

Acute Disease↗
PubMed1978

A survey of the effect of some drugs, chemicals, and enzymes on calcium oxalate precipitation in the rat kidney.

A single intraperitoneal injection of sodium oxalate was used to induce intrarenal tubular precipitation of calcium oxalate in rats. This experimental model was used to screen the efficacy of hydrochlorothiazide, orthophosphate, methylene blue, trypan blue, retinal folic acid, neuraminidase, and lysozyme in retarding intratubular calcium oxalate precipitation. Orthophosphate caused a 53 per cent reduction in calcium oxalate precipitation relative to the control animals.

Animals↗
PubMed1984

Polyethylene glycol precipitates in serum during and after erythema nodosum leprosum--study of their composition and anticomplementary activity.

Polyethylene glycol (PEG) precipitates obtained from sera were characterized and quantitated in 20 borderline lepromatous (BL) and polar lepromatous (LL) patients with moderate to severe erythema nodosum leprosum (ENL) before and four weeks after treatment with anti-ENL drugs, e.g., cortisone, clofazimine, chloroquine, or aspirin. Although the clinical severity of ENL subsided, there was no significant clearance of material that precipitates with PEG from the circulation. These precipitates had variable anticomplementary properties.

Antigen-Antibody Complex↗
PubMed1980

Inhibition of immune precipitation by complement.

Immune precipitation of bovine serum albumin (BSA) by rabbit anti-BSA antibody (Ab) was studied at 37 degrees C in the presence of normal human serum, normal rabbit serum, decomplemented serum and reagents permitting complement activation either by the classical pathway or the alternative pathway. Inhibition of precipitation occurred in the presence of complement. Antibody-excess complexes were kept soluble more easily than complexes formed at equivalence. Human serum was a better inhibitor than rabbit serum. Analysis of the phenomenon showed that during the first minutes of the reaction immune complexes were maintained in solution by the classical pathway only, but at later stages the alternative pathway was essential. Such soluble immune complexes precipitated after further incubation for 24 hr. The subsequent addition of ethylenediamine tetra-acetate (EDTA) to serum at 37 degrees C holding immune complexes in solution led to a slow aggregation of the complexes. Their size was found to be approximately 25S as assessed by sucrose density-gradient ultracentrifugation and they bore C3 and C4 fragments.

Animals↗
PubMed1982

[The larva precipitation test with Ascaris suum and Toxocara canis larvae].

Investigations were made by means of a larvae precipitation test (LPT) on different laboratory animals (pigs and white mice, and pigs, rabbits, guinea pigs and white mice respectively) experimentally infected with Ascaris suum and Toxocara canis respectively for the serological evidence of specific A. suum and T. canis antibodies. Living A. suum larvae isolated from the lungs of experimentally infected white mice forming oral, excretion porus and cuticula precipitates proved to be a suitable antigen for the intravital evidence of prepatent A. suum infections in pigs and mice. By using living T. canis larvae from lungs, liver and brain of infected mice as antigen prepatent T. canis infections in pigs, rabbits, guinea pigs and mice were serologically proved because of precipitates on oral and excretion porus. It was found for the first time that frozen preserved larvae of A. suum and T. canis are suitable for the evidence of specific antibodies and--because of the faster and more exact determination of the results as well as the possible preserving of the antigen--superior to the test on living larvae.

Animals↗
PubMed1982

Antibody activity and complement-mediated solubilization of precipitates during the immune response.

The avidity of antibodies against human serum albumin (HSA) and the complement-mediated solubilization of HSA anti-HSA precipitates has been investigated during the immune response in rats, mice, rabbits, and guinea-pigs. The avidity of the anti-HSA antibodies was quantitatively determined and expressed as the amount of HSA required to solubilize 50% of 10 ng HSA anti-HSA precipitate. In rats, from 25 to 100 days after primary immunization the avidity of the anti-HSA antibodies increased approximately 100-fold, whereas the affinity did not change significantly. The increase in avidity was accompanied by a thirty-six-fold decrease in the amount of immune precipitate that could be solubilized by complement. Booster injections of the rats did not prevent the increase in avidity (thirteen-fold) that occurred from 25 to 50 days after the first immunization; however, the subsequent eight-fold increase in avidity from 50 to 100 days could partially or completely be abolished by secondary immunizations. A close, inverse relationship between the avidity of the anti-HSA antibodies and the rate of complement-mediated solubilization was observed. In addition, an increase in avidity without a change in affinity of anti-HSA antibodies and a decrease in the rate of complement-mediated solubilization was found during the immune response against HSA not only in rats, but also in mice, rabbits, and guinea-pigs.

Animals↗
PubMedDate not supplied

[Effect of pluviometric precipitation on the physical, chemical, and health/hygiene aspects of water from three public water supplies].

Aiming to know the influence of the pluviometric precipitation over the physical chemical and bacteriological characteristics of the water coming from three sources of public supply, and to verify the probable origin of faecal contamination, tests of total coliforms, faecal coliforms, faecal streptococci and mesophilic microorganisms, as well as the determination of pH, temperature and turbidity of 156 water samples were done. The samples were taken from a stream, a drain and an artesian well, located in the city of Jaboticabal, SP, Brazil. The results obtained showed that the occurrence of pluviometric precipitation determined a significant increase of the number of total coliforms in the water samples from the stream. The use of the ratio CF/EF, indicate the probable origin of the faecal contamination only in the samples of the water coming from the stream, which were defined as being of human origin. In relation to the physical-chemical composition it was noticed that the influence of the pluviometric precipitation over the turbidity appeared to be higher and significant in the samples of water of the stream.

Brazil↗
PubMed1993

Effects of modulated and continuous microwave irradiation on pyroantimonate precipitable calcium content in junctional complex of mouse small intestine.

The pyroantimonate precipitable calcium content of intestinal epithelial cells was investigated in mice following total body irradiation with 2450 MHz continuous and low frequency (16 Hz) square modulated waves. In the control animals the reaction products appeared in the intercellular space of adjacent cells including intermediate junctions and desmosomes and were absent in the area of tight junctions. Immediately after low frequency modulated microwave irradiation at 0.5 and 1mW/cm2 power densities, a rapid distribution of pyroantimonate precipitable calcium content was observed. The pyroantimonate deposits were located on the cytoplasmic side of lateral membrane, in the area of junctional complex, including tight junction, and in other parts of lateral plasma membrane. These changes were reversible and 24 hours after the irradiation the distribution of pyroantimonate deposits was similar to the control. Continuous waves with same energy not altered the distribution of precipitable calcium. We conclude the low frequency modulated microwave irradiation can modify the calcium distribution without heat effects.

Animals↗
PubMed1975

[Investigations on the influence of NO2 and SO2 as well a combination of the two gases on the production of precipitating antibodies in guinea-pigs (author's transl)].

The influence of NO2 and SO2 or their combination on the production of precipitating antibodies was studied in guinea pigs. The gas concentration has been 10 mg/m3; the continuous exposure began 3 days before sensitization and lasted up to the testing date. Sensitization was done s.c. and i.m. with fresh chicken albumen plus complete Freund's adjuvans. Production of precipitating antibodies was tested by the double diffusion method of Ouchterlony. Moreover total protein content was measured and an immunelectrophoretic separation of the protein fractions was performed with polyvalent antiguinea pig serum. The statistical evaluation of the results has yielded no support in favour of an interaction of NO2 and SO2 or their combination in the concentration used on the formation of precipitating antibodies.

Animals↗
PubMed1993

A nonpeptidic delta opioid receptor agonist, BW373U86, attenuates the development and expression of morphine abstinence precipitated by naloxone in rat.

The effect of (+-)-4-((alpha-R*)-alpha-((2S*,5R*)-4-allyl-2,5-dimethyl-1- piperazinyl)-3-hydroxybenzyl)-N,N-diethylbenzamide (BW373U86), the first potent nonpeptidic, highly selective delta opioid receptor agonist, on morphine dependence was studied in rats. Continuous infusion of BW373U86 by a subcutaneously implanted osmotic minipump did not induce any abnormal behavior. After 6 days of BW373U86 infusion, intraperitoneal injection of a high dose of naloxone or naltrindole did not precipitate morphine-like abstinence syndromes. Furthermore, a single injection of BW373U86 did not induce abstinence syndromes or modulate morphine abstinence precipitated by naloxone in chronic morphine-treated rats. However, naloxone-precipitated abstinence syndromes in morphine-dependent rats were partially suppressed by BW373U86 in a dose-dependent manner when the compound was infused subcutaneously before and throughout morphine treatment. Abstinence signs such as wet-dog shake, forelimb tremor and teeth chattering were either suppressed or the intensity was significantly attenuated in these BW373U86-infused rats. This effect was antagonized by naltrindole. These data show that chronic infusion of BW373U86 does not produce physical dependence and that it attenuates some abstinence behaviors in morphine-dependent rats via delta opioid receptors.

Animals↗
PubMed1993

Quantitative analysis of concentration-response curves for precipitated abstinence responses in the opiate-dependent guinea pig ileum.

Our group has introduced a theoretical model of drug-receptor-effector interactions that can account for most of the kinetic aspects of opiate dependence and abstinence. The present study analyzes the experimental concentration-response curves for precipitated abstinence responses in the isolated guinea pig ileum and compares them with the curves generated by the mathematical model. Two experimental series were included: in the first, the effects of morphine exposure time on dependence development were analyzed; in the second, the effects of morphine concentration were studied. The results show that both the exposure time and morphine concentration determine the magnitude of precipitated abstinence responses. Dependence can be detected after exposure times to opiates as short as 7.5 min. The concentration-response curves for abstinence responses precipitated by naloxone in ilea exposed to morphine for different periods showed: 1) an initial increase in Emax; 2) a parallel shift to the left in the position of the abstinence curves as dependence develops; and 3) an asymptotic limit to the displacement on the left. The results presented here fit well with theoretical predictions. Practical and theoretical implications are discussed.

Animals↗
PubMed1996

Buprenorphine's physical dependence potential: antagonist-precipitated withdrawal in humans.

Buprenorphine is a partial mu opioid agonist with demonstrated efficacy in the treatment of opioid dependence. One potential advantage of buprenorphine over full mu opioid agonists is its reported low physical dependence profile. This study systematically examined physical dependence produced by maintenance with a clinically relevant dose of buprenorphine using antagonist challenge procedures. In this residential laboratory study, eight opioid-dependent volunteers maintained on 8 mg/day of sublingual buprenorphine were each challenged on independent occasions with placebo, i.m. naloxone (0.3, 1.0, 3.0 and 10.0 mg/70 kg) and p.o. naltrexone (0.3, 1.0 and 3.0 mg/70 kg) 14 hr after their daily buprenorphine dose using a repeated measures, cross-over design. Both naloxone and naltrexone precipitated time- and dose-dependent withdrawal, as evidenced by changes in subject-rated, observer-rated and physiological measures. Significant precipitated withdrawal occurred at 3.0 and 10 mg/70 kg i.m. of naloxone and 3.0 mg/70 kg p.o. of naltrexone. These results indicate that buprenorphine maintenance produces physical dependence and that i.m. naloxone and p.o. naltrexone produce equivalent effects in withdrawal precipitation under these conditions. Findings have implications for selection of antagonist doses for use in formulating combination agonist/antagonist medications and for use in transition of drug abusers from buprenorphine to antagonist maintenance therapies.

Adult↗
PubMed1977

[Diagnostic value of the allergy test and precipitation reaction for the intravital diagnosis of trichinelliasis in swine].

A total of twenty-two experimentally infected pigs, presenting from 250 to 12000 Trichinellae per kilogram body weight, were studied by the skin allergy test, the tube precipitation reaction, and the double gel diffusion technique after Ouchterlony in the course of one year following infection. Use was made of a Trichinella antigen obtained by the Tanner and Gregory's modified method. Unspecific allergy reactions were observed in 2.04% of 104 control pigs, and 2 of the infected ones did not react to the antigen diluted 1:1000. To decrease the cases of unspecific reactions a suggestion was made to extend the antigen from 1:5000 to 1:10000 and to read the result of the reactions not earlier than the 45th min. after injecting the antigen and the physiologic saline. The precipitation reaction proved positive in a comparatively short period--up to the fourth month of infection, and in sporadic cases up to the 7 1/2 month. Unspecific precipitation was observed in 18.7% of a total of 53 control sera. Ouchterlony's diffusion technique was shown to be specific, revealing trichinellosis in the animals from the 15th to the 365th day after the infection had been carried out. It was most markedly expressed from the 30th to the 120th day. It is suggested to use the skin allergy test on farms with a record of swine trichinelloses, all positively reacting pigs being serologically studied after Ouchterlony.

Animals↗
PubMed1976

Circling behavior after narcotic drugs and during naloxone-precipitated abstinence in rats with unilateral nigral lesions.

Unilateral lesions of the substantia nigra zona compacta (SNC) in rats were produced by electrolytic coagulation or by an injection of 6-hydroxydopamine. Two to 5 weeks later, after being preselected for amphetamine-induced ipsilateral circling behavior, the animals were administered narcotic agonists or antagonists and their circling behavior was observed. Morphine, methadone, levorphanol, nalorphine or pentazocine induced ipsilateral circling movements; both naloxone and dextrorphan were without effect. Ipsilateral circling was also observed in rats with unilateral electrolytic lesions after administration of agents that are thought to enhance central dopaminergic activities: d-amphetamine, l-dopa and apomorphine. In rats with unilateral electrolytic or 6-hydroxydopamine SNC lesions that were rendered highly morphine-dependent by multiple-morphine pellet implantation, contralateral (C) circling behavior was observed within 1 to 2 minutes after a naloxone challenge; the onset and duration of C circling behavior coincided with the initial appearance and duration of precipitated-morphine withdrawal signs. C circling was also observed after administration of putative dopamine receptor blockers, haloperidol and pimozide in rats with either unilateral electrolytic or 6-hydroxydopamine SNC lesions. Morphine pretreatment diminished both the C circling intensity and the appearance of withdrawal signs observed after a naloxone challenge in morphine-dependent, SNC-lesioned rats. The naloxone-precipitated withdrawal in unilaterally lesioned morphine-dependent rats was accompanied by a 20% elevation of neostriatal dopamine in the intact side. In contrast to the effects of a chronic SNC lesion in decreasing neostriatal dopamine, a 77% increase was observed in the lesioned side 30 minutes after electrolytic coagulation. Thus, narcotic agonists and partial agonists may enhance central dopaminergic activities and naloxone-precipitated withdrawal may involve a diminution in central dopaminergic activities of the nigroneostriatal pathway.

Animals↗