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At least 19 recordsLinked to original sources
PubMed1977

Studies of urticaria and acute serum sickness with the C1q precipitin test.

The C1q precipitin test was performed in serum samples from five groups of patients: (1) 20 patients with acomplementemic systemic lupus erythematosus glomerulonephritis (SLE), (2) 2 patients with serum sickness due to the administration of horse serum, (3) 2 patients with serum sickness preceding hepatitis B, (4) 50 patients with chronic urticaria, and (5) 30 normal controls. Positive C1q precipitin tests were found in all patients with SLE and the four cases of serum sickness. Positive tests correlated with depressed serum complement (C3 and C4) levels and were found only in the early phase of serum sickness. Urticaria patients uniformly had negative C1q precipitin tests and normal serum complement levels.

Acute Disease↗
PubMed1975

Fluorescent virus precipitin test.

A fluorescent virus precipitin test (FVPT) for the serologic identification of small particulate antigens such as viruses has been described. The test has several advantageous characteristics: (a) It is probably as sensitive as any serologic test (i.e., aggregates with dimensions of 0.2 mum are detectable; therefore, complexes containing as few as three large viruses would give a positive test). (b) Cultivation of the virus is not required. (c) Since an indirect test can be used, only a single fluorescent conjugate is needed to permit the detection of a number of viruses. (d) The indirect test can be used to detect antiviral antibody. (e) The FVPT is rapid and reliable. (f) Its simplicity should enhance its general acceptance and application.

Animals↗
PubMed1975

Application of agar-gel precipitin test for the detection of Sendai virus antibody in rat sera.

A simplified agar-gel precipitin test was performed for the detection of Sendai virus antibody in rat sera. A close correlation was observed between detection of antibodies by complement-fixation test and agar-gel precipitin test. No correlation was found between results obtained by hemagglutination-inhibition test and agar-gel precipitin test in sera with HI titer of less than 1:8.

Animals↗
PubMed1979

A modified quantitative precipitin test which is rapid, sensitive and reproducible.

A modification of the standard quantitative precipitin test is described. The new procedure, which utilizes polyethylene glycol (PEG) at both the 37 degrees C and 4 degrees C incubation stages, provides a convenient quantitative precipitin test assay which is more reliable and much faster than the standard assay. Moreover, the modified or PEG assay gives a quantitative measure of antibody concentration even when antisera of low titre are tested. The sensitivity of the capillary-tube test is also enhanced when the supernatant solutions contain PEG.

Animals↗
PubMed1978

Schistosomiasis japonica in Barrio San Antonio, Basey, Samar in the Philippines: II. Quantitative fecal examination and circumoval precipitin tests.

An improved quantitative stool examination technique (MFCT) and two variations in the performance of the circumoval precipitin test, one using whole serum (SCOPT) and the other employing the eluate from finger prick blood dried on filter paper (FPCOPT), were evaluated in a field study to detect infection with S. japonicum among residents of an endemic barrio in Samar. The sensitivity of SCOPT was above 90%, that of MFCT was between 80 to 90%, while that of FPCOPT was only about 50%. Intensity of infection as judged by fecal egg excretion and duration of infection as indicated by age were shown to be determinants of serum reactivity (and hence sensitivity of the two serodiagnostic tests). The relative insensitivity of FPCOPT observed in this work, also evident in some published data of previous workers, puts to doubt the wisdom of using this technique as the procedure of choice in epidemiologic surveys in the Philippines as currently favored in that country. Atypical positive reactions in circumoval precipitin tests using whole serum were detected which may make the differentiation of relatively recent from old infections possible.

Adolescent↗
PubMedDate not supplied

[Co-agglutination as an alternative to precipitin testing in streptococcal grouping (author's transl)].

Grouping of beta-hemolytic streptococcal strains was performed over a six months period on a total of 102 isolates. The purpose was to compare the Lancefield method with three different possibilities offered by the Co-agglutination technique. The results show that the Co-agglutination is as reliable as precipitin testing but it can be much more sensitive and rapid than any other method.

Agglutination Tests↗
PubMed1976

Detection of neonatal calf diarrhea virus, infant reovirus-like diarrhea virus, and a coronavirus using the fluorescent virus precipitin test.

Thirty-four calf and five infant fecal specimens were tested for the neonatal calf diarrhea virus (NCDV) and for the reovirus-like infantile diarrhea agent; respectively. The procedures used were the fluorescent virus precipitin test and immune electron microscopy. Fourteen of the calf stools contained detectable NCDV, and four of the five infant stools contained the reovirus-like human agent. Infectious NCDV was detected in four of the 34 calf fecal specimens when Madin-Darby bovine kidney cell cultures that had been inoculated with supernatant fluids from stool suspensions were stained with fluorescent antibody. The 20 calf stools that did not have detectable virus were examined for the bovine corona diarrhea virus. Coronavirus was found in two of these specimens.

Animals↗
PubMedDate not supplied

Identification of avian mycoplasma isolates by the agar-gel precipitin test.

Recent isolates of Mycoplasma gallisepticum and Mycoplasma synoviae were readily typed by the agar-gel precipitin test with antigens prepared by freezing and thawing, sonic vibration, or sodium dodecyl sulfate. Specific antisera prepared in rabbits or in foot-pad-inoculated chickens were adequate for culture typing. Relatively few sera from chickens and turkeys in naturally infected flocks reacted positively. The precipitin reaction was highly specific, however.

Animals↗
PubMed1978

Increasing the predictive value positive of the precipitin test for the diagnosis of deep-seated candidiasis.

Three hundred fifty human sera were tested by double immunodiffusion, crossed-line electrophoresis, and crossed immuno-affinoelectrophoresis with a concanavalin A intermediate gel for precipitating antibodies to antigens present in cytoplasmic extracts of Candida albicans. Sera from 48 of 287 hospitalized patients at risk of invasive candidiasis contained precipitating antibodies to Candida antigens. Of these 48 sera, 27 had precipitating antibodies only to cell-wall antigens present in the cytoplasmic extract, and 21 sera had precipitating antibodies to both cytoplasmic and cell-wall antigens. The latter sera came from patients who were 2.5 times as likely to have deep-seated candidiasis as those patients with precipitins exclusively to cell-wall antigens. Sera from seven of 22 patients with vaginal candidiasis and 10 of 41 patients with other fungal infections had precipitating antibodies to C. albicans cell-wall antigens; only two of these sera also contained precipitating antibodies to the cytoplasmic antigens. Crossed immunoaffinoelectrophoresis with concanavalin A reduced the number of false-positive results and increased the predictive value positive of the precipitin test for deep-seated candidiasis from 31% to 71%.

Antigens, Fungal↗
PubMedDate not supplied

Virus-neutralization versus agar-gel precipitin tests for detecting serological response to infectious bursal disease virus.

The virus-neutralization (VN) test was found much more sensitive than the agar-gel precipitin (AGP) test for detecting prior exposure to infectious bursal disease (IBD). Many sera that were negative in the AGP test were found to have VN antibodies, and virtually all sera in a commercial flock were free of precipitin but had VN titers. VN titers varied widely on a flock basis, and revaccination of an 8-month-old flock through the drinking water did not alter the antibody titers. Inoculation of maternally immune chicks at 7 days of age with IBD virus resulted in a good serologic response by both the AGP and VN tests.

Age Factors↗
PubMed1977

A precipitin test for the diagnosis of human abdominal angiostrongyliasis.

A precipitin reaction was observed when sera of cotton rats infected either naturally or experimentally with Angiostrongylus costaricensis were tested by gel double-diffusion against sera obtained from three biopsy-confirmed human cases of A. costaricensis. With immunoelectrophoresis, the antigen was demonstrated in the serum of infected rats. The antibody in the human serum was mostly of the IgG type. No cross reactions were seen with sera from individuals infected with the common intestinal helminths, or individuals serologically positive for Toxocara, A. cantonensis, Chagas' disease, amebiasis, leishmaniasis, toxoplasmosis, or syphilis.

Abdomen↗
PubMed1978

A micro-procedure for quantitative precipitin tests.

A new method for the quantitative analysis of antigens and antibodies has been based on (1) ultrafiltration of the antigen-antibody precipitates through silver membranes of 0.2 micrometer pore size in a specially designed multisample apparatus, and (2) spectrophotometric determination at 210 nm of the amount of proteins in the antigen-antibody precipitates dissolved in 0.01 N HCl. At this wavelength, the = C = O group of the polypeptide chains constitutes the main chromophoric group. In comparisons with the ninhydrin color reaction, protein determination by low UV spectrophotometry, e.g., at 210 nm, was shown to be about 6 times more sensitive, permitting analysis of samples containing from 1.0 to 35.0 microgram of antigen. The concentration range of protein solutions in 0.01 N HCl which is measured at low UV can be regulated by a factor of 8--10 by changing absorption between 200 and 230 nm. Comparison of the ultrafiltration microtechnique with the standard quantitative precipitin microtechnique involving centrifugation of precipitates was made in 4 different antigen-antibody systems. The new technique was found to be as accurate as the standard technique. It allows completion of analysis within only 5--6 h. The standard precipitin technique, by contrast, requires a 5--7-day reaction period for completion.

Animals↗
PubMed1977

Host feeding patterns of Connecticut mosquitoes (Diptera: Culicidae).

Blood-engorged Coquillettidia perturbans, Psorophora ferox, Culex, Culiseta, and Aedes mosquitoes were collected principally by sweep net from salt marsh and woodland habitats in Connecticut. Of the 570 mosquitoes tested, precipitin tests identified the origins of 517 blood meals and revealed distinct host feeding patterns. Aedes mosquitoes fed chiefly on mammals; A. abserratus, A. cantator, and A. vexans showed selectivity for cattle and (or) horses. A. cantator also obtained blood from avian hosts and, in some instances, showed mixed passerine-mammal blood meals. These findings increase the vector potential of this salt marsh mosquito for eastern equine encephalomyelitis virus. Feedings on deer by A. abserratus suggest potential involvement of this mosquito in the transmission of certain subtypes of California encephalitis. Culex-pipiens, C. restuans, Culiseta melanura, and Cs. morsitans dyari acquired blood almost exclusively from passeriform birds.

Aedes↗
PubMed1977

A cellulose acetate membrane precipitin (CAP) test for amoebiasis.

A simple precipitin test (CAP) using cellulose acetate membrane has been devised and evaluated against the gel diffusion precipitin (GDP) test. In 251 sera tested by both methods, the CAP was never negative when the GDP was positive (110 sera). 34 sera were negative by the GDP but positive by the CAP; in all of these the patients either had a past history of amoebiasis or were considered to have active amoebiasis. The CAP is technically very simple, the result is available within four and a half hours, and the membranes can be impregnated with antigen and stored for several months. The CAP is slightly more sensitive than the GDP and remains positive longer after the patient has been cured; it seems to be equally specific.

Amebiasis↗
PubMed1979

Schistosomiasis japonica in Barrio San Antonia, Basey Samar, in the Philippines: III. The plasma circumoval precipitin test-procedure and use in epidemiologic studies.

A plasma circumoval precipitin test is proposed as the basic diagnostic tool for epidemiologic studies on schistosomiasis japonica in the Philippines. The collection of plasma, the preparation of the COP test slide, and the reading and interpretation of results are described in detail with pertinent comments. The cost, advantages and usefulness of the test are also discussed.

Child↗