Variability of corticospinal and spinal reflex excitability for the ankle dorsiflexor tibialis anterior across repeated measurements in people with and without incomplete spinal cord injury.

To adequately evaluate the corticospinal and spinal plasticity in health and disease, it is essential to understand whether and to what extent the corticospinal and spinal responses fluctuate systematically across multiple measurements. Thus, in this study, we examined the session-to-session variability of corticospinal excitability for the ankle dorsiflexor tibialis anterior (TA) in people with and without incomplete spinal cord injury (SCI). In neurologically normal participants, the following measures were obtained across 4 days at the same time of day (N = 13) or 4 sessions over a 12-h period (N = 9, at 8:00, 12:00, 16:00, and 20:00): maximum voluntary contraction (MVC), maximum M-wave and H-reflex (Mmax and Hmax), motor evoked potential (MEP) amplitude, and silent period (SP) after MEP. In participants with chronic incomplete SCI (N = 17), the same measures were obtained across 4 days. We found no clear diurnal variation in the spinal and corticospinal excitability of the TA in individuals with no known neurological conditions, and no systematic changes in any experimental measures of spinal and corticospinal excitability across four measurement days in individuals with or without SCI. Overall, mean deviations across four sessions remained in a range of 5-13% for all measures in participants with or without SCI. The study shows the limited extent of non-systematic session-to-session variability in the TA corticospinal excitability in individuals with and without chronic incomplete SCI, supporting the utility of corticospinal and spinal excitability measures in mechanistic investigation of neuromodulation interventions. The information provided through this study may serve as the reference in evaluating corticospinal plasticity across multiple experimental sessions.

Selective pigment medium for Streptococcus agalactiae.

Increased awareness of the importance of Streptococcus agalactiae (Group B streptococcus) in neonatal morbidity and mortality has demonstrated the need for a selective and differential primary plating medium. In this report we describe a selective pigment medium containing colistin and nalidixic acid that allows presumptive identification of S. agalactiae from the primary plate, even when specimens are polymicrobic. A preliminary study compared the value of three media for pigment production by 137 known S. agalactiae strains. This was followed by a clinical laboratory trial using the best of these pigment media at an obstetric hospital in which 581 specimens from neonates, female reproductive tracts, and urinary tracts were screened. Subsequent to the clinical laboratory trial, an epidemiological investigation using the selective pigment medium was conducted on a mother/infant population. Of the 1,331 specimens screened for S. agalactiae, 75 (5.6%) were positive on 5% sheep blood agar and 79 (5.9%) were positive on the selective pigment medium.

Susceptibility of Pittsburgh pneumonia agent (Legionella micdadei) and other newly recognized members of the genus Legionella to nineteen antimicrobial agents.

The susceptibilities of 11 strains representing the five recognized species of Legionella were determined by agar dilution testing on buffered charcoal-yeast extract agar. All of the legionellae tested were susceptible to rifampin, erythromycin, rosaramycin, chloramphenicol, and the aminoglycosides and were resistant to clindamycin and vancomycin. Susceptibilities to penicillins and cephalosporins were variable. Legionella micdadei, Legionella bozemanii, and Legionella gormanii were susceptible to these agents, but minimal inhibitory concentrations for each species were different. Legionella dumoffii resembled Legionella pneumophila in being resistant to penicillin, cephalothin, and cephamandole and susceptible to moxalactam and cefoxitin. All species except L. micdadei produced beta-lactamase.