Identified higher-order neurons controlling the feeding motor program of helisoma

A bilaterally symmetrical pair of neurons in the anterior region of the cerebral ganglia of the snail Helisoma trivolvis were found to have excitatory input to the feeding motor program contained in the buccal ganglia. Intracellular microelectrodes were used to stimulate and record from these cells while the motor output of the buccal ganglia was monitored with a combination of intracellular and extracellular recordings. Experimentally evoked tonic activity in an individual cerebral cell could initiate and maintain the patterned motor output from buccal ganglia, characteristic of the activity underlying buccal mass feeding movements. The rate of buccal motor output could be modified directly by varying the firing frequency of the cerebral cell. Cobaltous chloride backfills of cerebrobuccal connectives revealed that these higher-order neurons were the only large cells in the anterior portion of the ganglia to send processes into the connectives. Furthermore, they are the only cells in this region to fluoresce when processed with a sucrose-phosphate-glyoxylic acid solution, indicating that they contain an indoleamine, probably serotonin. Application of low concentrations of serotonin to isolated buccal ganglia or buccal ganglia-buccal mass preparations mimics the effects of the cerebral cells' activity on the buccal motor output, implying that serotonin is a putative transmitter for these cerebral cells.     

Infant Vocalization: An Index of Maternal Attitude Toward the Child

Brief observations of mother-stimulated infant vocalizationwere perform ed during pediatric clinic visits on 4- to 6-month-oldinfants to determine whether mothers with positive attitudestoward the pregnancy and/or the in fant would have infants whovocalized more during clinic visits. Mothers with more positiveattitudes toward the pregnancy, assessed prenatally, had infantswho showed significantly more vocalization during clinic visitsat 5 months, 6 months, and the combination of 5 and 6 months.Mothers with more positive attitudes toward the infant had infantswho showed signcantly more vocalization at 4 months and thecombination of observations at 4 months and 6 months. Resultssuggest that brief observations of vocalization during clinicvisits may be useful as a rough index of the quality of themother-child interaction.     

Haemophilus ducreyi Outer membrane determinants, including DsrA, define two clonal populations

The Haemophilus ducreyi outer membrane component DsrA (for ducreyi serum resistance A) is necessary for complete resistance to normal human serum (NHS). When DsrA expression in 19 temporally and geographically diverse clinical isolates of H. ducreyi was examined by Western blotting, 5 of the strains expressed a different immunotype of the DsrA protein (DsrA(II)) than the well-characterized prototypical strain 35000HP (DsrA(I)). The predicted DsrA proteins expressed by the DsrA(II) strains were 100% identical to each other but only 48% identical to that of strain 35000HP. In addition to the DsrA(II) protein, class II strains also expressed variant forms of other outer membrane proteins (OMPs) including NcaA (necessary for collagen adhesion A), DltA (ducreyi lectin A), Hlp (H. ducreyi lipoprotein), major OMP, and/or OmpA2 (for OMP A2) and synthesized a distinct, faster-migrating lipooligosaccharide. Based on these data, strains expressing DsrA(I) were termed class I, and those expressing DsrA(II) were termed class II. Expression of dsrA(II) from strain CIP 542 ATCC in the class I dsrA(I) mutant FX517 (35000HP background), which does not express a DsrA protein, rendered this strain resistant to 50% NHS. This demonstrates that DsrA(II) protein is also critical to serum resistance. Taken together, these results indicate that there are two clonal populations of H. ducreyi. The implications of two classes of H. ducreyi strains differing in important antigenic outer membrane components are discussed.     

Enhancement of normal neutrophil chemiluminescence by chronic granulomatous disease neutrophils

Neutrophils and other phagocytic cells from patients with chronic granulomatous disease (CGD) lack the ability to generate reactive oxygen intermediates (ROI), although other phagocytic functions appear to be intact. The effects of CGD neutrophils on the ability of normal neutrophils to produce ROI as measured by luminol-enhanced chemiluminescence (CL) were examined. Normal neutrophils (2×10⁵) had a peak CL response to phorbol myristate acetate (PMA; 20 ng/ml) of 6.5±0.9 mV, while the CL response of CGD neutrophils was completely absent. However, the addition of CGD neutrophils (8×10⁵) to normal neutrophils (2×10⁵) markedly increased the peak CL response to PMA to 11.0+-1.1 mV (P < 0.001). The peak response of normal neutrophils (2×10⁵) alone to the peptideN-formyl-methionyl-leucyl-phenylalanine (FMLP; 10^–6 M) was 9.0±1.1mV, and this increased to 22.2±3.5 mV (P < 0.001) when 8×10⁵ CGD neutrophils were added and to 18.9±3.6 mV (P<0.005) when 4×10⁵ CGD neutrophils were added. Thus, CGD neutrophils increase the release of ROI from normal cells, suggesting nonoxidative regulatory factors in ROI production.This work was supported in part by grants GI517-02 and 0008-08 from the Cystic Fibrosis Foundation and HD-09800 and AI-15332 from the National Institutes of Health.     

Long-term azithromycin use is not associated with QT prolongation in children with cystic fibrosis

Chronic Azithromycin (AZM) is a common treatment for lung infection. Among adults at risk of cardiac events, AZM use has been associated with cardiovascular harm. We assessed cardiovascular safety of AZM among children with CF, as a secondary analysis of a placebo-controlled, clinical trial, in which study drug was taken thrice-weekly for a planned 18 months. Safety assessments using electrocardiogram (ECG) occurred at study enrollment, and then after 3 weeks and 18 months of participation. Among 221 study participants with a median of 18 months follow-up, increased corrected QT interval (QTc) of ≥30 msec was rare, at 3.4 occurrences per 100 person-years; and incidence of QTc prolongation was no higher in the AZM arm than the placebo arm (1.8 versus 5.4 per 100 person-years). No persons experienced QTc intervals above 500 msec. Long-term chronic AZM use was not associated with increased QT prolongation.     

Acknowledgment of Ad Hoc Reviewers for Volume 13

Note

Acknowledgment of Ad Hoc Reviewers for Volume 13