Antigenic characteristics of polypeptides of Coxiella burnetii isolates

Eighteen Coxiella burnetii strains from a variety of clinical and geographical sources were screened for antigenic variation of polypeptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with Coomassie brilliant blue (CBB) staining or immunoblotting. These polypeptide profiles showed the greatest variability in the region from 33 to 8.1 kDa. Such differences in the antigenicity of the polypeptides were also recognized by immunoblotting with 15 various mouse anti-C. burnetii antisera. In addition, we detected a polypeptide at about 28 kDa which was immunodominant in strains from human cases of acute Q fever, milk and ticks but not immunogenic in strains from human cases of chronic Q fever. These findings suggest that this polypeptide is a marker to distinguish between acute and chronic strains.

Antigenic characteristic of the lipopolysaccharides of Coxiella burnetii isolates

Lipopolysaccharides (LPSs) of 8 isolates of Coxiella burnetii from a variety of clinical and geographical sources could be divided into four groups based on molecular heterogeneity in silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles in the region of the 10 to 17 kDa. The lipopolysaccharide of group 1 was identified on isolates from acute Q fever patient, milk and tick. The three remaining groups were primarily found on isolates from human cases of chronic Q fever. These LPSs shared many antigenic epitopes, as determined by immunoblotting with mouse anti-C. burnetii antisera.

Clinical evaluation of a new PCR assay for detection of Coxiella burnetii in human serum samples

A nested PCR method was developed for the detection of Coxiella burnetii in human serum samples. Two pairs of oligonucleotide primers were designed to amplify a 438-bp fragment of the com1 gene encoding a 27-kDa outer membrane protein of C. burnetii. The primers amplified the predicted fragments of 21 various strains of C. burnetii but did not react with DNA samples from other microorganisms. The 438-bp amplification products could be digested with restriction enzymes SspI and SalI. The utility of the nested PCR was evaluated by testing human serum samples. The com1 gene fragment was amplified from 135 (87%) of 155 indirect immunofluorescence test (IF)-positive serum samples and from 11 (11%) of 100 IF-negative serum samples. The nested PCR with primers targeted to the com1 gene appeared to be a sensitive, specific, and useful method for the detection of C. burnetii in serum samples.

Orbital pseudotumors: value of short inversion time inversion-recovery MR imaging

PURPOSE

To evaluate magnetic resonance (MR) signal intensities of orbital pseudotumors on short inversion time inversion-recovery (STIR) images and to predict the effect of treatment.

MATERIALS AND METHODS

Sequential MR examinations were performed in 17 patients with orbital pseudotumors, before and after treatment. All patients underwent MR imaging with T1- and T2-weighted spin-echo or fast spin-echo sequences, and STIR sequences with two 0.5-T systems. Quantitatively and qualitatively, the differences in signal intensities among three therapeutic response groups (good, mild, and no responses) were analyzed for each pulse sequence.

RESULTS

Quantitatively, both contrast and contrast-to-noise ratio on STIR images corresponded well to the results of response to therapy for all background markers; contrast and contrast-to-noise ratio values in the good response group were the largest, while those in the no response group were the smallest (P < .0001). Qualitatively, the signal intensities of the lesions in the good response group were interpreted as hyperintense to the cerebral cortex in 14 (93%) or 11 (73%) of 15 lesions by two observers, respectively, while in the no response group, both observers assessed 16 (89%) of 18 lesions as hypo- or isointense to the muscle (P < .0001).

CONCLUSION

STIR images showed a variety of signal intensities in the lesions, and the signal intensities on the STIR images helped predict the response to the therapy in orbital pseudotumors.

[Concentration of sulbenicillin in human serum and myocardial tissue]

The concentration of sulbenicillin in the serum and myocardial tissue of 13 patients were determined at cardiac surgery. About 100 mg/kg of sulbenicillin were administered intravenously for 60 minutes. Right auricle resected at the vena caval cannuration was examined for myocardial tissue. The serum concentration was also examined every 30 minutes after injection, 30 minutes, 60 minutes, 90 minutes, 120 minutes and 150 minutes. Mean values of serum concentration were 213.6 micrograms/ml, 432.5 micrograms/ml, 181.6 micrograms/ml, 236.3 micrograms/ml and 101 micrograms/ml, respectively. The values determined in myocardial tissue were 146.5 micrograms/g (60 minutes), 39.2 micrograms/g (90 minutes), 66.0 micrograms/g (120 minutes) and 23.5 micrograms/g (150 minutes). The mean value of concentration ratio of sulbenicillin in myocardial tissue was 0.23 of serum concentration. The high myocardial tissue levels of sulbenicillin suggests that its use at cardiovascular surgery would protect the myocardial tissue from the bacterial infections.