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At least 217 records · Page 12Linked to original sources
PubMed1996

[Identification of food sources of Anopheles aquasalis (Diptera: Culicidae) by precipitin test in the State of Rio de Janeiro, Brazil].

Anopheles aquasalis has shown local variations in blood-host preference in Brazil: it seems to be anthropophilic in the northeast and zoophilic or opportunistic in the Amazon and other regions. A study was carried out in Guapimirim county, State of Rio de Janeiro, from May to November 1992, for the purpose of identifying the blood meal source of this anopheline by capillary tube precipitin test. A total of 1,366 females were captured at natural resting-places, 725 of which were blood-fed. The gut content of 473 blood fed females reacted to the antisera used (human, cow, horse, pig, dog and chicken). The majority of the females-356 (75.3%)-had blood from only one source. A substantial bovine preference was observed-52.2% had fed on cows, 29.8% on horses, 10.7% on pigs, 4.5% on chickens and 1.7% on dogs, but only few had fed on man (1.1%) and none on rats. On the other hand, 24.7% of the females had fed on more than one host, mainly on cows and horses. It was assumed that An. aquasalis is zoophilic in southeastern Brazil, feeding on a wide variety of animals, the cow being the primary host.

Animals↗
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↗
PubMed1988

A nonimmunoglobulin precipitin to tissue extracts in pathological human sera.

An alpha-globulin component was noted in pathological human sera, which produced gel precipitation reactions with extracts of human and animal liver. The highest incidence of the precipitin was found in malaria (95%), renal graft rejection (81%), and rheumatoid arthritis (57%). The precipitinogen was thermostable and ethanol soluble; of two precipitation lines formed by this component, one merged into identity reaction with a line produced by commercial lecithin of bovine origin. The possible diagnostic application of the reactions noted was considered.

Alpha-Globulins↗
PubMed1987

Detergent-treated Newcastle disease virus as an agar gel precipitin test antigen.

A soluble Newcastle disease virus (NDV) agar gel precipitin (AGP) antigen was prepared by treating 100-fold concentrated NDV with a nonionic detergent. Virus concentration prior to detergent treatment was best accomplished by ultracentrifugation or by a simple, less expensive, and more practical method involving acid (HCl) precipitation of NDV. Virus concentrated by polyethylene glycol precipitation was found to have a low antigen titer and was not considered suitable as an AGP antigen. Antigens derived from the LaSota, Roakin, and Texas GB strains formed at least two lines of identity in the AGP test as early as 24 hr after inoculation of the agar gels. Virus used for AGP antigen production could be grown in chicken embryos from an NDV-immune as well as susceptible breeder flock. The NDV AGP antigen was found to be stable after 20 consecutive freezing and thawing cycles and storage at -20 C or 4 C for at least 6 months. Detergent-treated NDV was used as an AGP test antigen to determine serum antibody responses of chickens following infection and vaccination. Hemagglutination-inhibition, virus neutralization, and enzyme-linked immunosorbent assay antibody production was also evaluated for comparative purposes. The AGP test was found to be useful as an aid in diagnosing field infections and assessing inactivated virus vaccination responses. These purposes were achieved by demonstrating an increase in the number of AGP positive chickens between preinfection and postinfection or vaccination bleedings. The ease of performance and low cost of the AGP test favors its use for screening large numbers of serum samples, perhaps in conjunction with a quantitative serological test.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

The circumoval precipitin reaction on Schistosoma mansoni eggs as seen by scanning electron microscopy.

The circumoval precipitin reaction on Schistosoma mansoni eggs was examined for the first time by scanning electron microscopy. The precipitates appeared as layered segmenters, and apparent fusion of adjacent precipitates was observed. This suggests that the single precipitates seen by light microscopy may on occasion be a collection of several precipitates exuding from nearby pores. The precipitates appeared on all areas of the egg surface except the spine.

Animals↗
PubMed1982

Circumoval precipitin antigens for the diagnosis of schistosomiasis. II. Isolation of functional antigens.

A serum was prepared by immunizing rabbits with circumoval precipitin (COP) immune complexes isolated by Protein A Sepharose affinity chromatography. This serum, positive in the COP test, was used to isolate by antibody affinity chromatography the COP antigens contained in crude schistosome egg antigens (SEA). The COP antigens were then applied to the enzyme-linked immunosorbent assay (ELISA) and compared to SEA. In a rabbit immunized repeatedly with the COP immune complexes the reactivity in the ELISA to both SEA and the COP antigens increased with time. In a primary infection of S. mansoni the reactivity to both antigen preparations rose in parallel; however, SEA showed higher reactivity. Interestingly, with the COP antigens a dramatic increase in antibody response was obtained in the serum of the 4th week in two separate groups of infected mice. This is probably a reflection of the common antigens between worms and eggs since two of the three major antibodies to the COP antigens identified previously are absorbable with lyophilized S. mansoni worms.

Animals↗
PubMed1988

Schistosoma mansoni cationic egg antigens (CEF6): immunoserology with oxamniquine-treated patients and involvement of CEF6 in the circumoval precipitin reaction.

The serologic activity of a cationic fraction (denoted CEF6) of Schistosoma mansoni soluble egg antigen was compared in an ELISA with that of the unpurified soluble egg antigen for the ability to detect human infections and for the prediction of chemotherapeutic success in patients followed up to 5 years post-treatment with oxamniquine. The cationic fraction correctly identified 100% of 20 patients as infected with S. mansoni; moreover, 50% (10 of 20) seroconverted to negative by 2 years post-treatment and 100% of 15 patients tested were negative 5 years post-treatment. In general, the cationic fraction was superior to the unpurified soluble egg antigen for the detection of infection and for the prediction of chemotherapeutic success. The cationic fraction also exhibited greater immunologic specificity over the unpurified soluble egg antigen in that the latter exhibited higher titers than the former to antibodies against heterologous parasite antigens (Fasciola hepatica, Clonorchis sinensis, Paragonimus westermani adult worms; Trichinella spiralis larvae). Moreover, rabbit antisera raised against egg antigens isolated from the precipitation formed when fresh S. mansoni eggs are incubated with S. mansoni infection of immunization sera (known as circumoval precipitin reactions or COP) reacted strongly with the cationic fraction in ELISA. In addition, antiserum to the cationic fraction as well as antisera against either of the two antigenic components of this fraction, known as antigens alpha 1 and omega 1, all give positive COP reactions when incubated with fresh S. mansoni eggs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Comparison of direct and modified direct complement-fixation and agar-gel precipitin methods in detecting chlamydial antibody in wild birds.

Detection of chlamydial antibody in serums of wild birds was compared for the following methods: direct complement-fixation (DCF), modified DCF (MDCF), and agar-gel precipitin (AGP). The birds species used were great-tailed grackles (Cassidix mexicanus), common grackles (Quiscalus quiscula), brown-headed cowbirds (Molothrus ater), bronzed cowbirds (Tangavius aeneus), and mourning doves (Zenaida macroura). The birds were either inoculated with an isolate of Chlamydia psittaci obtained originally from turkeys or kept as uninoculated cagemates. DCF detected antibody in most inoculated common grackles, mourning doves, and brown-headed cowbirds. It was unreliable, however, for great-tailed grackles and bronzed cowbirds inoculated intramuscularly. MDCF method detected antibody in all inoculated birds except 1 mourning dove, and gave higher titers than did DCF. AGP detected antibody in all inoculated brown-headed cowbirds and all mourning doves, 1 inoculated and 1 exposed great-tailed grackle, and none of the other 2 species. Chlamydiae were apparently transmitted to the uninoculated great-tailed and common grackles and mourning doves, for antibody was detected by all 3 methods in these species kept as uninoculated cagemates.

Animal Population Groups↗
PubMed1998

Worm recovery and precipitin antibody response in guinea pigs and rats infected with Clonorchis sinensis.

Guinea pigs (Hartley strain) and rats (Wistar strain) were each fed 200 and 100 Clonorchis sinensis metacercariae, respectively. Five animals from each species were sacrificed weekly between 1-8 weeks postinfection (WPI) and then at 12, 16, 20 and 30 WPI for collection of worms, bile and sera. The overall worm recovery rates for guinea pigs and rats were 18.7% and 12.4%, respectively. Only one of the five rats examined at 20 WPI still harbored one worm, while all were worm-free at 30 WPI. By a double diffusion test, no antibodies were detected against C. sinensis adult antigens in the bile juice. Serum antibodies were detected in at least 95% of the infected guinea pigs between 4-30 WPI and rats between 3-16 WPI. Precipitin antibodies seemed to be correlated with the presence of live worms in rats that had been infected for more than 12 weeks.

Animals↗
PubMed2000

The circumoval precipitin reaction in Fasciola. Detection of shell pores by scanning electron microscopy.

Precipitation reaction was detected around Fasciola eggs containing mature miracidia when they were incubated for 20 minutes with the sera of acute and chronic fasciolosis patients. The reaction was of the bleb type. The amount of blebs formed around the eggs was greater in case of acute than chronic fasciolosis. Scanning electron microscopy illustrated pores in the shell of Fasciola eggs. It is probable that the metabolic antigen passes through these pores leading to the positive circumoval precipitin reaction in cases of Fasciola infection. Antibodies specific to Fasciola excretory/secretory (E/S) egg antigens were not detected in the sera of Schistosoma cases.

Animals↗
PubMedDate not supplied

[Isolation and partial study of an anti-hemoglobine precipitine in "Biomphalaria glabrata" (author's transl)].

A protein (PaHb) with a precipiting capacity with regard to normal and pathological human hemoglobin as well as horse and hen hemoglobin has been separated on immunoadsorbent from hemolymph of Biomphalaria glabrata. The joining of PaHb and hemoglobin takes place at the level of the polypeptidic chain. A reconnaissance of the spatial structure of the globin seems to exist. The absence of heme does not lead to a decrease in the intensity of the reaction. The coefficient of the sedimentation of PaHb is of 2.74 S and its molecular weight has been estimated at 47,000 per chromatography in thin layer. The divalent cation MgCl2 strengthens the intensity of the reaction, as for CaCl2 no change is observed, and in the presence of sodium citrate one observes a clear decrease in the reaction. The intensifying of the reaction when in presence of divalent cation MgCl2 could be the result of a stabilization or an activation of the natural structure of PaHb when in presence of Mg. PaHb shows no fonctional impairment after exposure at 65 degrees C during 45 min. The localization of PaHb in the total antigenic structure of the hemolymph is situated around the level of the 5th precipitine line. The functional role of the protein seems to carry the hemoprotein of the hemolymph.

Animals↗
PubMed1975

Evaluation of the circumoval precipitin test using dried blood on filter paper as a diagnostic tool in epidemiological survey for schistosomiasis.

The suitability of the circumoval precipitin (COP) test in a field survey for schistosomiasis in the rural area using dried blood samples on filter paper was evaluated with reference to the stool examination by the merthiolate-iodine-formaldehyde concentration (MIFC) technique. Both blood and stool samples were collected simultaneously among over 600 inhabitants of two schistosomiasis endemic communities (barrios) of Palo, Leyte, Philippines. The method of collecting blood samples on filter paper, the procedure for COP test and its sensitivity in detecting schistosomiasis cases are described. Blood sampling from finger prick was acceptable to both adults and children so that blood samples were readily obtained while the collection of stool samples required repeated visits to the homes. A significantly higher percentage of schistosomiasis positives were obtained by COP test than by stool examination. The COP test results were comparable to the stool examination results on the following aspects: 1) highest infection rate in the 10-19 age group and lowest infection rate in the 60 years old and above; 2) positive rates for schistosomiasis did not differ significantly between the two barrios and 3) no family accumulation of the disease in the two communities was observed in this survey in 1972. The stability of the antibody in filter paper, the reliability of the test and the simple and rapid procedures involved make this filter paper method of COP test very practical and suitable for schistosomiasis survey in rural areas.

Adolescent↗
PubMed1975

Evaluation of a technique of circumoval precipitin test using blood taken on filter paper and a microtiter technique of complement fixation test of Schistosoma japonicum.

For the circumoval precipitin test (COPT) blood was taken on quantitative blood sampling filter paper by finger prick from outpatients at the Schistosomiasis Control Pilot Project, Palo, Leyte, Philippines. The volume of serum available per strip of filter paper was 0.04 ml and this was extracted at 1:3, 1:5 and 1:8 dilutions. Lyophilized eggs of Schistosoma japonicum were mixed with the diluted serum on a microscope glass slide and incubated at 37 degrees C for 2 days. The reaction was read following the criterion made by Yokogawa et al. [11]. The serum at 1:8 was too dilute to make correct diagnosis; serum at 1:3 dilution contained too much hemoglobin which made microscopic observation difficult and the extract at 1:5 was found to be appropriate. There was no remarkable difference in antigenicity among 3 preparations of lyophilized eggs from Kofu strain, Japan, and those of new and old preparations from Philippine strain. Under the best condition, false negative results appeared in 15.3% of 152 outpatients in Leyte and false positives in 2% of 50 human sera collected in Tokyo. This method of COPT is not satisfactory for the diagnosis of individual cases but is useful in the epidemiological assessment of Schistosoma infections because of the simplicity of blood sampling from dwellers of infested areas and also because it shows nearly the same sensitivity as that of a single fecal examination by the MIFC method. A microtiter technique of complement fixation test (CFT) was also studied. This method, however, was less sensitive than the COPT or a single fecal examination as to give 23.7% false negatives. Frequency distributions of CF and COP titers were analysed among egg positive, egg negative and treated groups. The results showed that treatment with stibophen had little influence in lowering the serum response, especially in COPT.

Blood Specimen Collection↗
PubMed1991

Application of alcohol- or acetone-fixed Schistosoma eggs as an alternative to lyophilized eggs for the circumoval precipitin test.

Antigenicity of Schistosoma mansoni and S. japonicum eggs preserved in ethanol or acetone were assessed in a circumoval precipitin (COP) assay. The egg antigens were found to retain sufficiently their COP reactivity for the diagnosis of both schistosomiasis mansoni and japonica, although their reactivity became lower than that of lyophilized eggs. These alternative preparations for COP tests have advantages, such as keeping eggs directly in fixatives soon after the egg-purification process. Furthermore, evaporation-process may cause eggshell cleavages which facilitate the reaction. The possible usefulness of those eggs in COP assays in local endemic areas is discussed.

Acetone↗
PubMed1989

Evaluation of the intraoval precipitin reaction (IOP) for diagnosis of schistosomiasis.

On using lypholized eggs of S. mansoni isolated from mice, and that of S. haematobium isolated fresh from man. IOP was not observed and the sensitivity of (COP) was less in the former than in the latter. The IOP reaction should be taken into account when the ovum precipitin test is employed for schistosomiasis serodiagnosis and seroepidemiology, as being more sensitive than the COP reaction.

Animals↗
PubMed1987

Prevalence of serum precipitins against microbes in mouldy hay, and of chronic bronchitis and farmer's lung with respect to farmers' occupational health hazards.

During the farmers' occupational health study 1979-82, the work conditions of 3,358 randomly selected farmers were investigated with respect to occurrence of work-related health hazards. The farmers also underwent a health examination in their local health centre, and precipitating antibodies against four microbes present in mouldy hay were analyzed. Results of the precipitin tests and the symptoms of chronic bronchitis and farmer's lung were analyzed with respect to the occurrence of work-related exposures to biological agents and dust in farming. The prevalence of antibodies against Aspergillus umbrosus was largest (6.9%) among farmers with biological health hazards. The occurrence of antibodies against any of the four microbes was associated more with work-related biological agents than with dust exposures. Chronic bronchitis and farmer's lung were also more common among farmers with exposures to biological agents and dust than among those without such exposures. The work conditions were investigated independently of the results of the health examinations. Occurrence of chronic bronchitis and farmer's lung are associated with the work-related health hazards in farming. For proper delivery of occupational health services methods of investigating work-related health hazards need to be improved.

Antibodies, Bacterial↗
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↗