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PubMed1975

Gel precipitin tests for hepatitis-B surface antigen. False positive reactions due to the presence of staphylococcal antigen in contaminated plasma samples.

Plasma samples contaminated with coagulase-positive staphylococci were found to give a false positive precipitin line for hepatitis-B surface antigen in gel tests. The staphylococcal antibody was found to be present in both normal immunoglobulin and anti-hepatitis-B surface antigen immunoglobulin preparations and also in many normal plasma samples.

Antigens, Bacterial↗
PubMed1975

Significance of the gel diffusion precipitin test for invasive amoebiasis.

The double diffusion precipitinin test for amoebiasis, has been evaluated in invasive amoebiasis. It gave positive percentages of 91-3 and 90-0 in cases of amoebic liver abscess and amoebic dysentery. False positive rates of 8-0 per cent and 0-0 per cent were obtained in miscellaneous non-amoebic disorders and in apparently healthy subjects, respectively. Its comparison with the indirect haemagglutination test revealed it to be slightly less sensitive but more specific. The agar gel precipitinin test became positive whenever the indirect haemagglutination titres were 1:256 or more. The adsorption studies revealed that both tests detected different types of antibodies. The use of the gel diffusion test is recommended as a routine method for amoebiasis as it is simple to perform in areas where sophisticated laboratory methods are not available.

Adsorption↗
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↗
PubMed1979

Evaluation of commercial latex agglutination reagents for grouping streptococci.

A total of 155 strains of beta-hemolytic streptococci were serologically grouped by conventional techniques (Lancefield extraction and capillary precipitin testing) and by latex agglutination (LA). Agreement between conventional and LA techniques was 97% when the instructions of the manufacturer for the LA technique were followed. Agreement of 99% was obtained when modified autoclave extracts were used as antigens in the LA procedure. A total of 82 strains of non-beta-hemolytic streptococci were also tested by conventional, prescribed LA, and modified autoclave procedures. The agreement between conventional techniques and both LA procedures was 76%. However, when serological cross-reactions in the conventional grouping procedures were considered as errors, the accuracy of identification of both LA procedures was 88% among the non-beta-hemolytic strains. Of 13 strains of Streptococcus bovis, 10 did not react with the LA group D reagent but were serogroup D by conventional techniques. More S. bovis strains were grouped by the LA technique when extracts of 20 ml of broth cultures were used as antigens; however, cross-reactions were observed with non-group D strains when this technique was applied to them.

Hemolysis↗
PubMed1975

The quantitation of antibody in farmer's lung syndrome using a radioimmunoassay. Results of a clinical survey and comparison of three serological methods.

Three serological tests for antibody to Micropolyspora faeni, the precipitin test (Ouchterlony double diffusion test in two dimensions) the fluorescent antibody test (double-layer technique using patient's serum in middle layer) and a quantitative radioimmunoassay for IgG antibody were applied to cases of farmer's lung syndrome and compared as to their value in diagnosis and management of these cases. Of twenty-one cases with clinical symptoms only ten (48%) had positive precipitin tests, while all (100%) showed a positive fluorescent antibody test. Sixteen (76-4%) were found by the radioimmunoassay to have antibody in excess of the normal controls. The remaining five cases with symptoms had a range of antibody levels which overlapped with those of symptom-free individuals (with sera negative to fluorescent antibody tests). The precipitin test was positive above a level of 75 mug/ml of IgG antibody as determined by the radioimmunoassay, whilst the cases judged by the fluorescent antibody test to be positive were all above a level of 35 mug/ml of IgG antibody. Application of the radioimmunoassay to a group of farmers in the West of Scotland successfully detected high antibody levels in all with clinical evidence of farmer's lung syndrome; farmers who were symptom-free also had measurable antibody. The advantages of a quantitative test for antibody levels in the management of cases of this disease are discussed.

Antibodies, Bacterial↗
PubMed1979

A rapid staphylococcal coagglutination technic to differentiate group A from other streptococcal groups.

A rapid staphylococcal coagglutination technic for differentiating group A from other streptococcal groups properly classified 500 isolates of beta-hemolytic streptococci when compared with the results of a reference capillary precipitin test. Presumptive classification of the same 500 isolates by bacitracin susceptibility produced a significant number of incorrect identifications. The findings further document the inherent inaccuracy of the bacitracin susceptibility test and suggest that the staphylococcal coagglutination technic may be a simple, accurate, inexpensive alternative for identification of group A streptococci.

Agglutination Tests↗
PubMed1979

Extractable antigen shared by Peptostreptococcus anaerobius strains.

Extracts from several species of gram-positive cocci were prepared by a modification of the Rantz-Randall autoclave method and tested for reactions with rabbit anti-Peptostreptococcus anaerobius (ATCC 27337 and VPI 5737) sera in a capillary precipitin test. Antigen preparations from two reference strains of P. anaerobius (ATCC 27337 and VPI 5737) and six clinical isolates of P. anaerobius reacted with the P. anaerobius antisera. These extracts formed a line of identity by immunodiffusion and displayed at least one precipitin line by immunoelectrophoresis. Absorption of the antisera with either the autoclaved extract or a 10% whole-cell suspension from each of the eight P. anaerobius strains removed the precipitin line(s) observed during immunodiffusion and immunoelectrophoresis. Extracts prepared to other species of Peptococcus, Peptostreptococcus, and Streptococcus did not react with the P. anaerobius antisera in a capillary precipitin test. In addition antisera to Lancefield groups A to G did not react with the extracts from the eight P. anaerobius strains. Preliminary chemical analysis of the extracts from the eight strains showed that they contained approximately 0.2 mg of carbohydrate per ml and 3.6 mg of protein per ml. The rabbit anti-P. anaerobius sera used in this study detected a common antigen(s) shared by strains of P. anaerobius, but did not react with autoclave extracts prepared from other species of gram-positive cocci. This extractable antigen could be used in a capillary precipitin test to rapidly identify P. anaerobius strains isolated in the clinical microbiology laboratory.

Antigens, Bacterial↗
PubMed1979

[Studies on the diagnosis of schistosomiasis japonica. (1) Circumoval precipitin (COP) test as a method of screening of the subjects for fecal examination (author's transl)].

Examinations were performed on 351 individuals of Shikishima village, Yamanashi Prefecture. Three fecal samples were collected at one-week intervals and examined by MIFC method without iodine. Reactions with a diameter of 9 mm or more in wheal and/or 20 mm or more in erythema were regarded as the positive for the intradermal reaction using Melcher's antigen (1 : 1,000). For the COP test, each one drop of serum and a saline suspension of eggs were mixed on a microscope slide and sealed a coverslip with vaseline. The number of eggs showing precipitates were counted after 48 hrs at 37 degrees C. The results showed that all the precipitates were small in size in the COP titer less than 40%. Medium precipitates appear first in the cases of a 40.% class and the percentage increased thereafter as the COP titer increased. Large precipitate was found in 10% of the eggs affected in a 50% class and found in 40% in the titer of a 80% class. Of 351 tested, a significant higher rate of egg-passers (42.7%, 41/96) was obtained in the COP reactors, as compared with other two groups; 19.4% (41/211) in the dermal reactors, 11.7% (41/351) in the total subjects. Moreover, the egg-passers were recovered in 60--70% of the cases in the COP titer of more than 70%. It was considered that the COP test was a useful diagnostic method for schistosomiasis japonica and the sensitivity and efficiency of this test were superior to those of intradermal test with regarded to the screening of the subjects for fecal examination.

Feces↗
PubMed1977

Studies in chronic allergic bronchopulmonary aspergillosis. 3. Immunological findings.

Precipitin tests by two different methods, double-diffusion (DD) and counterimmunoelectrophoresis (CIE), and measurements of total and specific IgE against Aspergillus fumigatus were made in 50 patients with chronic allergic bronchopulmonary aspergillosis and in three control groups--atopics with a positive immediate prick test to A. fumigatus but no evidence of allergic aspergillosis, atopics with a negative prick test to A. fumigatus, and non-atopics. Precipitins were found in 84% and 78% of the patients with aspergillosis by the DD and CIE methods respectively. Precipitins were also found in 6 out of 27 (22%) patients with a positive prick test to A. fumigatus but no evidence of aspergillosis and in 1 of 24 patients with a negative prick test to A. fumigatus. The means of specific and total IgE values were significantly higher in the group of patients with aspergillosis than in the three other groups of patients. The increase in specific but not total IgE showed a statistically significant correlation with positive precipitin tests in the patients with aspergillosis. Total IgE but not specific IgE values were significantly higher (0-02 less than P less than 0-05) in patients who had had a transient radiographic shadow in the previous three months. Positive precipitin tests were also significantly correlated with the number of transient shadows in the past and with the interval of time since the last transient shadow.

Aspergillosis↗
PubMed1979

A review of laboratory methods for identification of group B streptococci (Streptococcus agalactiae).

A selected review is presented of the history of Group B streptococcal infections and the laboratory tests used to identify Group B streptococcus (Streptococcus agalactiae), an opportunistic pathogen which causes serious infections in newborn infants and compromised patients in other age groups. Its isolation may be increased by growth in a selective medium. The methods for Group B streptococci identification include the hydrolysis of sodium hippurate, the CAMP reaction, pigment production, and antibiotic disk susceptibility. Also, immunological tests, such as Lancefield's classical precipitin test, immunofluorescence staining, counterimmunoelectrophoresis, and coagglutination are available.

Bacteriological Techniques↗
PubMed1977

Evaluation of candida precipitin and agglutinin tests for the diagnosis of systemic candidiasis in burn patients.

Candida agglutinin and precipitin tests were performed on a group of burned patients without evidence of systemic candidiasis to determine whether tests could be used to distinguish between colonization and systemic disease, as has recently been reported. There were considerable numbers of false-positive results using both tests. These false-positive results occurred regardless of the candida colonization status of the patient. We conclude that these tests are of little diagnostic value in burn patients.

Agglutination Tests↗
PubMed1978

Occupational hypersensitivity lung disease.

A case of occupational hypersensitivity pneumonitis caused by an air conditioning unit is presented. Aspergillus fumigatus and aureobasidium pullulans were cultured from this unit and antibodies to these organisms were found the patient's blood. The case shows that this disease may present in a very subtle form and may be diagnosed by a culture from the patient's environment and an easily performed blood precipitin test. The importance of searching for this type of lung disease and the need for obtaining precipitin tests are stressed.

Air Conditioning↗
PubMed1978

Counterimmunoelectrophoresis in the detection of antibodies to Schistosoma japonicum.

Counterimmunoelectrophoresis (CIE) was used to detect antibodies to Schistosoma japonicum soluble egg antigen in 118 sera from people living in a schistosomiasis endemic area in the Philippines. The sera were also tested for antibodies by the circumoval precipitin test (COPT); 53% were found positive by CIE and 48% positive by COPT. No significant differences were found between the tests (P = 0.18 by McNemar's test). Cross-reactions with sera from patients with intestinal capillariasis and monkeys with experimental angiostrongyliasis were not found and no false reactions were detected with sera from "normal" controls. The CIE test as used in the present studies was found to be comparable to the COPT in sensitivity and specificity as related to cross-reactivity with sera from nematode infections such as intestinal capillariasis and angiostrongyliasis. Results are usually available quickly with nearly 70% of any reactions occurring within 1 h. The test should be of value in seroepidemiologic surveys in schistosomiasis-endemic areas.

Adolescent↗