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At least 181 records · Page 10Linked to original sources
PubMed1971

A gel-precipitin test for the diagnosis of varicella.

Varicella may be difficult to distinguish clinically from smallpox. Because of this difficulty, much anxiety has occurred when cases of chickenpox are misdiagnosed as smallpox in areas where smallpox is not endemic. Surveillance of smallpox has also been complicated in areas where eradication programmes are in progress. A gel-diffusion test has been developed that can detect varicella-zoster (V-Z) antigen in vesicular fluid. This simple test, which can be performed in the field, identified V-Z antigen in vesicular fluid in all 14 cases of varicella or zoster that were tested. No reactions were observed with vaccinia precipitin antigen. The production of V-Z precipitin antigen in tissue culture provided a positive control that yielded lines of identity with vesicle fluid. This material was also used to screen human sera for suitable antisera for the test.

Chickenpox↗
PubMedDate not supplied

[Comparative analysis between the circumoval precipitin test and ELISA with raw antigens for the diagnosis of schistosomiasis in Venezuela].

Schistosomiasis has special characteristics in Venezuela, since the majority of the infected population is asymptomatic and the elimination of eggs is very low, difficulting in this way parasitologic diagnosis. It is thus necessary to develop sensitive and specific immunologic methods to be applied in field surveys. The present study compares two serologic tests for Schistosomiasis, the enzyme linked immunosorbent assay (ELISA) with eggs (SEA) and adult (AWA) antigens and the traditional circumoval precipitation test (COPT). Sensitivity and specificity of the test were performed being 100% and 92% in COPT, 79% and 71% in ELISA-SEA and 71% and 91% in ELISA-AWA respectively. Advantages and disadvantages of each test are discussed.

Adolescent↗
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↗
PubMed1969

Influence of various parameters on the sensitivity of precipitin tests in farmer's lung by immunodiffusion and immunoosmophoresis.

Dilutions of a standard serum were made in saline and in negative sera, and comparative tests by immunodiffusion and by immunoosmophoresis were made against one antigenic component of Micropolyspora faeni (Thermopolyspora polyspora). The endpoint dilution of the standard serum in saline and serum in wells of different sizes was ascertained in each test. The endpoint dilution was unaffected by the distance of separation (from 1.5 mm to 6 mm) between the origins of serum and antigen, provided that the tests were read at times appropriate to each separation, the greater separations requiring longer periods of development. Higher endpoint dilutions were obtained by the use of 1% Noble agar in immunoosmophoresis than with 1% Ionagar no. 2 (Oxoid). This difference was more noticeable when low osmophoresis potentials were used.

Antigens↗
PubMed1976

Identification of Propionibacterium acnes and related organisms by precipitin tests with trichloroacetic acid extracts.

The serological identification of Propionibacterium acnes, P. granulosum, and P. avidum, using trichloroacetic acid extracts, is described. With antisera prepared against reference strains, the method has been tested on 142 strains recently isolated from human skin. All except two of the strains could be identified serologically, and there was excellent agreement between the serological results and the fermentation pattern of the strains. Two serological types of P. acnes and two of P. avidum were identified, but only one of P. granulosum.

Antigens, Bacterial↗