Activation of C3 and factor B in normal human serum by P. ovale was demonstrated using a standard unidirectional immunoelectrophoresis technique. Activation of complement by the alternative (properdin) pathway is a possible mechanism by which P. ovale may mediate an inflammatory response.
An avidin-biotin horseradish peroxidase method was used to detect antibodies to Naegleria fowleri and N. lovaniensis in human serum samples. Antibodies were detected in 101 specimens from 115 hospital patients ranging in age from 15 to 98 years. Class-specific anti-immunoglobulins identified antibodies as IgG and IgM. IgG antibody titers to both species ranged from 1:20 to 1:640. Seven of 15 serum samples collected from newborn infants also demonstrated IgG antibodies to these organisms with a titer range of 1:20 to 1:80. The immunoperoxidase test and Western blot analysis of selected serum samples demonstrated a close similarity in serological results between N. fowleri and N. lovaniensis.
Lactamase testing of clinical isolates of staphylococci may be performed in commercial broth microdilution minimum inhibitory concentration plates, using a chromogenic cephalosporin reagent directly in a well containing a noninhibitory concentration of a semisynthetic penicillin which serves as an inducer. A total of 115 staphylococcal isolates tested in 0.25 to 0.50 ,ug of methicillin per ml in Mueller-Hinton broth showed 100% correlation with 1-lactamase tests performed on Mueller-Hinton agar, using 1-,ug oxacillin disk as an inducer.
In a comparison of two commercially available chlamydial isolation systems in which cycloheximide-treated McCoy cell monolayers are used, the system from Bartels Immunodiagnostic Supplies, Inc., Bellevue, Wash., was found to be superior to that from M. A. Bioproducts, Walkersville, Md. for the detection of Chlamydia trachomatis by iodine staining. Of 288 clinical specimens run in parallel, 47 (16.3%) were positive, with 16 of 47 positive results detected in the Bartels system only and 1 of 47 positive results detected in the M. A. Bioproducts system only (P < 0.001). A comparison of the number of inclusion-forming units per cover slip from clinical specimens and passaged isolates also showed that the Bartels cell system demonstrated higher inclusion counts than the M. A. Bioproducts system. In routine clinical use, overall isolation rates were higher (P < 0.001) and contamination rates were lower (P < 0.001) with the Bartels system as compared with results obtained in a previous time period in which the M. A. Bioproducts system was used.
The use of avidin-biotinylated peroxidase as a simple technique for light microscopic visualization of spirochetes is described. The three major genera of spirochetes-Treponema, Borrelia, and Leptospira-were stained with the avidin complex.
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