Mucorales species activation of a serum leukotactic factor.

Previous studies have suggested that the focal accumulation of phagocytic leukocytes is an important feature of the host response in mucormycosis. To ascertain the basis for this influx of inflammatory cells, we evaluated the effect of members of the order Mucorales, including species from the genera Rhizopus, Absidia, and Mucor, on the chemotactic activity of normal human serum for neutrophils and monocytes. Both hyphae and spores produced concentration-dependent chemotaxigenesis in serum to a maximum level equivalent to that produced by zymosan activation of serum. Chemotactic activity was similar for live and heat-killed hyphae. No leukotactic activity was demonstrated in the absence of serum. The pretreatment of serum with anti-C3 antibody, heating at 56 degrees C, or 0.01 M EDTA abolished the activity. The pretreatment of serum with 0.01 M ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid did not abolish the activity. These data provide evidence that the leukotactic activity of Mucorales species is generated through the alternative complement pathway.

Rocky Mountain spotted fever. Serological evidence of previous subclinical infection in children.

Serological tests for Rocky Mountain spotted fever were performed on single serum specimens from sixth graders from Forsyth County, North Carolina, an area highly endemic for this disease. Five of 508 *.098%) sera were positive (titer greater than or equal to 1:64) using the indirect fluorescent antibody method. Elevated Proteus agglutination antibody titers (greater than 1:160) to OX-19, but not ot OX-2, were common (19.6%) in these children. No correlation of those with positive OX-19 titers could be made with the cases demonstrating elevated indirect fluorescent antibody titers or with a history of urinary tract infection. These data suggest that the increased prevalence of elevated Proteus OX-19 antibody levels makes a single high titer unreliable in the diagnosis of Rocky Mountain spotted fever and that naturally acquired mild or asymptomatic subclinical cases of Rickettsia rickttsii infection occur.

Chemotaxin-induced changes in cyclic adenosine monophosphate levels in human neutrophils.

Incubation of the chemotactic agent N-formyl-methionyl-leucyl-phenylalanine with human neutrophils produced a rapid elevation of the intracellular level of cyclic adenosine monophosphate (cAMP). This cAMP spike occurred within 30 s after exposure and returned to normal by 5 min.

Pathology of Yersinia enterocolitica meningitis.

Yersinia enterocolitica, a gram negative aerobic non-haemolytic bacillus, has been identified as a cause of meningitis only once before and the neuropathological features of Y. enterocolitica meningitis have not been reported in the literature. We describe the pathological features of a case of acute fatal meningitis caused by Y. enterocolitica, serotype 0:18, in a 47-year-old male alcoholic with cirrhosis. The organism presumably reached the meninges via the blood stream from the abdominal cavity. Intravascular fibrin thrombi, both recent and organising, were associated with multiple foci of necrosis in the brain. In spite of vigorous antibiotic therapy for three weeks the organism was cultured from the brain at autopsy. Among the various infections caused by Y. enterocolitica, meningitis appears to be the most difficult to eradicate.

The use of videotape for off-line viewing of computer-assisted radionuclide cardiology studies.

Videotape offers an inexpensive method for off-line viewing of dynamic radionuclide cardiac studies. Two approaches to videotaping have been explored and demonstrated to be feasible. In the first, a video camera in conjunction with a cassette-type recorder is used to record from the computer display scope. Alternatively, for computer systems already linked to video display units, the video signal can be routed directly to the recorder. Acceptance and use of tracer cardiology studies will be enhanced by increased availability of the studies for clinical review. Videotape offers an inexpensive flexible means of achieving this.