Purpose:To evaluate the feasibility of dobutamine stress magnetic resonance (DSMR) in pediatric patients. Materials and Methods:The medical records of all DSMR studies performed on patients Յ22 years old at a single institution were retrospectively reviewed. The DSMR protocol included dobutamine doses up to 40 g/kg/minute and atropine to attain the target heart rate [0.85 ⅐ (220 -age)].Results: Thirty-two DSMR studies were performed in 28 patients (median age ϭ 7.3 years; range ϭ 0.8 -22 years). Twenty of the studies were performed under general anesthesia. The protocol was completed in 26 studies, technical problems and interruptions were few, and image quality scores (1-5) for all ventricular wall segments were high (mean ϭ 4.2). A heart rate Ն160 bpm was attained in 84% of the studies, a rate pressure product Ն20,000 beats ⅐ mm Hg in 87%, and a heart rate greater than or equal to the target heart rate in 19%. No serious adverse events occurred. One patient had an inducible wall motion abnormality. Interobserver agreement was 100% (kappa ϭ 1.0) for test positivity and 92% (kappa ϭ 0.72) for wall motion scores. Conclusion:DSMR in pediatric patients is feasible and provides high-quality imaging of all ventricular wall segments with low interobserver variability. Further exploration of DSMR in pediatric patients is warranted, particularly for those children who are unable to cooperate sufficiently for exercise stress or have poor acoustic windows.

The in vitro activities of ABT 773, telithromycin (HMR 3647), azithromycin, clarithromycin, erythromycin, and levofloxacin were tested against 20 strains of Chlamydia pneumoniae. The MIC at which 90% of the isolates were inhibited and the minimal bactericidal concentration at which 90% of the isolates were killed by ABT 773 were 0.015 g/ml (range, 0.008 to 0.015 g/ml). ABT 773 was the most active antibiotic tested in this study.The ketolides are a new class of macrolide antibiotics with a keto group replacing the L-cladinose moiety in position 3 and an alkyl-aryl extension at positions 11 and 12 of the lactone ring. The ketolides are acid stable and have activity against a broad range of respiratory pathogens, including multiresistant pneumococci, Haemophilus influenzae, Legionella species, and Mycoplasma pneumoniae (1,2,3,5,8). Chlamydia pneumoniae is an important cause of community-acquired respiratory infection in adults and children worldwide. Clinically, these infections cannot be readily differentiated from those caused by other "atypical" pathogens, such as M. pneumoniae. Data on the activity of ketolides against C. pneumoniae are limited; only the activity of telithromycin (HMR 3647) and HMR 3004 (RU 64004) has been evaluated so far (5, 10; F. Haider, F. Eb, and J. Orfila, Abstr. 35th Intersci. Conf. Antimicrob. Agents Chemother., abstr. F165, 1995). Therefore, we compared the in vitro activity of ABT 773 (a new ketolide antibiotic), telithromycin, azithromycin, clarithromycin, erythromycin, and levofloxacin against 20 isolates of C. pneumoniae.Isolates of C. pneumoniae tested included two reference strains, TW 183 (ATCC VR-2282) and AR39 (ATCC 53592), an isolate from a child with pneumonia from Japan, J21 (ATCC 1435), W 6805, an isolate from an adult with pneumonia from Wisconsin, and 16 isolates from a large United States multicenter treatment study of adults with communityacquired pneumonia. ABT 773, telithromycin, azithromycin, erythromycin, clarithromycin, and levofloxacin were provided as powders and solubilized according to the instructions of the manufacturers. Susceptibility testing of C. pneumoniae was performed with cycloheximide-treated HEp-2 cells grown in 96-well microtiter plates (7). Each well was inoculated with 0.1 ml of the test strain diluted to yield 10 3 to 10 4 inclusion-forming units per ml; the plates were centrifuged at 1,700 ϫ g for 1 h and incubated at 35°C for 1 h. Wells were then aspirated and overlaid with medium containing 1 g of cycloheximide per ml and serial twofold dilutions of the test drug. After incubation at 35°C for 72 h, cultures were fixed and stained for inclusions with fluorescein-conjugated antibody to the chlamydial lipopolysaccharide genus-specific antigen (Pathfinder; Kallestad Diagnostics, Chaska, Minn.). The MIC was the lowest antibiotic concentration at which no inclusions were seen.The minimal bactericidal concentration (MBC) was determined by aspirating the antibiotic-containing medium, washing wells twice with phosphate-buffered saline, and adding an...

The nucleoprotein of Lassa virus, strain Josiah, was expressed inEscherichia coli as an N-terminally truncated, histidine-tagged recombinant protein. Following affinity purification the protein was completely denatured and spotted onto nitrocellulose membrane. A total of 1 μg of protein was applied for detection of Lassa virus antibodies (LVA) in a simple immunoblot assay. Specific anti-Lassa immunoglobulin M (IgM) antibodies could be detected by increasing the amount of protein to 5 μg. A panel of 913 serum specimens from regions in which Lassa virus was endemic and from regions in which Lassa virus was not endemic was used for evaluating the sensitivity and specificity of the LVA immunoblot in comparison to those of an indirect immunofluorescence (IIF) assay. The sera originated from field studies conducted in the Republic of Guinea (570 serum samples) and Liberia (99 serum samples), from inpatients of the clinical department of the Bernhard-Nocht-Institute, Hamburg, Germany (94 serum samples), and from healthy German blood donors (150 serum samples). In comparison to the IIF assay the LVA immunoblot assay had a specificity of 90.0 to 99.3%, depending on the origin of the specimens. The sensitivity was found to be highest for the Guinean samples (90.7%) and was lower for the Liberian samples (75%). Acute Lassa fever was diagnosed by PCR in 12 of 59 (20.3%) patients with fever of unknown origin (FUO) from the Republic of Guinea. On admission to the hospital, nine Lassa fever patients (75%) were reactive by the IgM immunoblot assay. One of the patients was infected with a new Lassa variant, which showed 10.4% variation on the amino acid level in comparison to the prototype strain of Lassa virus, Josiah. Seven PCR-negative patients were reactive by immunoblotting. The positive and negative predictive values of a single IgM immunoblot result for acute, PCR-confirmed Lassa fever were therefore 53.6 and 93.0%, respectively. Because of its high negative predictive value, a single IgM immunoblot result will be valuable for excluding acute Lassa fever for cases of FUO in areas where Lassa fever is endemic.

Marfan syndrome (MS) is a connective tissue disease involving the cardiovascular, ocular, and the musculoskeletal systems. MS has variable phenotypic expression and is most often diagnosed in adult life. Infantile-onset MS is rare and is associated with severe cardiovascular manifestations; there is an extremely high mortality during the first 2 years of life. We present a case of a child with severe infantile MS who, during the course of infancy and early childhood, developed aortic root dilatation and polyvalvar insufficiency requiring subsequent successful replacement of the aortic root and of all cardiac valves. To our knowledge, this is the first reported case of quadrivalvar replacement in the pediatric age group.