Bone age assessment with conventional ultrasonography in healthy infants from 1 to 24 months of age.

BACKGROUND: Radiographic bone age determination is part of the routine evaluation of suspected growth disorders. Simplicity and low cost are its major advantages, but although the effective dose of ionizing radiation is low, it should be taken into consideration given its cumulative effect. OBJECTIVES: To assess the chronological ultrasonographic emergence of the ossification centers of the hand and wrist. MATERIALS AND METHODS: Cross-sectional study of healthy patients ages 1 to 24 months (n=498) from Buenos Aires, Argentina. All patients underwent ultrasonographic evaluation of the left hand and wrist to identify the different bone nuclei; a subgroup of infants had their nuclei measured (n=228). RESULTS: Girls showed an earlier emergence of the evaluated nuclei and a trend to a greater size than age-matched boys. Size-for-age relation showed linear increase. Carpal bones (capitate and hamate) were the first to appear, as early as from the first 3 months of life, an age gap not thoroughly present on the radiographic atlas developed by Greulich and Pyle. The distal epiphysis of the radius and the second metacarpophalangeal joint (index finger) followed in order of emergence. The proximal epiphysis of the first metacarpal bone (thumb) was the last to emerge and was infrequently found on boys at age 24 months. Overall, these findings are in accordance with the radiographic atlas. An ultrasonography atlas of the left hand and wrist was outlined for girls and boys. CONCLUSION: Conventional ultrasonography allows proper identification of the ossification centers of the hand and wrist and may become an innocuous follow-up tool for patients with growth disorders.

Effect of linezolid compared with glycopeptides in methicillin-resistant Staphylococcus aureus severe pneumonia in piglets.

OBJECTIVES: To investigate if compared with glycopeptides, antimicrobial therapy (AMT) with linezolid (LZD) improves the outcome in methicillin-resistant Staphylococcus aureus (MRSA) experimental pneumonia in mechanically ventilated piglets. METHODS: The MRSA minimal inhibitory concentration (MIC) was 0.5 for vancomycin (VAN), 0.25 for teicoplanin (TEI), and 2.0 microg/mL for LZD was inoculated in Largewhite-Landrace piglets divided into five groups. One group (n = 6) did not receive mechanical ventilation (MV) or AMT. Those in the remaining groups received MV and VAN (n = 9), TEI (n = 7), LZD (n = 9), or no AMT (n = 7). Plasma and BAL tumor necrosis factor-alpha, interleukin-6, and C-reactive protein (CRP) concentrations, postmortem lung pathology, cultures (lung, blood, and BAL) and plasma, epithelial lining fluid (ELF), and lung antibiotic concentrations were evaluated. MEASUREMENTS AND MAIN RESULTS: All piglets developed severe pneumonia; lung pathology score was lower in those receiving LZD vs those receiving glycopeptides (p = 0.049) or no AMT (p = 0.037). Serum CRP and serum and BAL cytokines increased; there were no differences between the groups. Fourteen died spontaneously at 44.4 +/- 16.8 h; the remaining 24 were killed after 72 to 96 h. The concentrations of the antimicrobial agents tested in 15 piglets were higher than the MIC for the three antimicrobial agents in peak and trough plasma, ELF, and lung specimens. Survival at 72 h was higher in the LZD comparing with the no-AMT group. CONCLUSIONS: Inoculation produced severe MRSA pneumonia. LZD AMT was associated with lower pathology score, better survival, and a trend to better clearance of MRSA, not attributable exclusively to pharmacokinetic or pharmacodynamic reasons.