Pasteurella multocida Bacterial Meningitis in a 33-Day-Old Infant

A 33-day-old previously healthy term female is admitted to the pediatric intensive care unit with fever, lethargy and bulging fontanel. Given concern for meningitis, a lumbar puncture is performed and empiric treatment is initiated. The cerebrospinal fluid culture results reveal Pasteurella multocida. The patient is treated with intravenous ampicillin for 3 weeks and discharged with close outpatient follow-up.

High-frequency percussive ventilation in a pediatric patient with hydrocarbon aspiration

INTRODUCTION

To describe ventilator management using a high-frequency percussive ventilator (HFPV), after other modes of mechanical ventilation failed.

DESIGN

Case series.

SETTING

Pediatric intensive care unit.

PATIENTS

Previously healthy 11-month-old male with severe aspiration pneumonitis from mineral oil.

INTERVENTIONS

The patient was initially placed on a conventional ventilator in a pressure-regulated volume-control mode but needed higher-than-normal pressures to maintain adequate ventilation. A decision was made to switch the patient to a pressure-control/pressure-support mode. At the end of the third day of pressure-control/pressure-support mode, a decision was made to attempt airway pressure-release ventilation. During a trial attempt, saturation levels deteriorated and a decision was made to place the patient on a high-frequency oscillator. The patient remained on this mode of ventilation for 6 days. On the sixth day, the chest radiograph showed a worsening of his pneumonia, and the patient started to deteriorate. A decision was made to try the HFPV in an attempt to mobilize secretions and any residual mineral oil. Immediately after initiating the HFPV and for 4 hrs thereafter, large amounts of secretions -- including a thick, oily substance -- were suctioned from the airways. Within 12-24 hrs, oxygenation improved dramatically and Fio2 was weaned. During the next 12 hrs, the patient was weaned off HFPV onto a conventional ventilator, and he was extubated 48 hrs after initiating HFPV.

CONCLUSIONS

In this case, HFPV used as an alternative mode of ventilation successfully mobilized secretions that were otherwise unobtainable and that we believe led to the swift recovery of this child. HFPV should be given consideration as a mode of ventilation when mobilization of secretions is an issue.

The gamma-subunit of skeletal muscle phosphorylase kinase contains two noncontiguous domains that act in concert to bind calmodulin

Phosphorylase kinase is a Ca2+-regulated, multisubunit enzyme that contains calmodulin as an integral subunit (termed the delta-subunit). Ca2+-dependent activity of the enzyme is thought to be regulated by direct interaction of the delta-subunit with the catalytic subunit (the gamma-subunit) in the holoenzyme complex. In order to systematically search for putative calmodulin (delta-subunit)-binding domain(s) in the gamma-subunit of phosphorylase kinase, a series of 18 overlapping peptides corresponding to the C terminus of the gamma-subunit was chemically synthesized using a tea bag method. The calmodulin-binding activity of each peptide was tested for its ability to inhibit Ca2+/calmodulin-dependent activation of myosin light chain kinase. Data were obtained indicating that two distinct regions in the gamma-subunit, one spanning residues 287-331 (termed domain-N) and the other residues 332-371 (domain-C), are capable of binding calmodulin with nanomolar affinity. Peptides from both of these two domains also inhibited calmodulin-dependent reactivation of denatured gamma-subunit. The interactions of peptides from both domain-N and domain-C with calmodulin were found to be Ca2+-dependent. Dixon plots obtained using mixtures of peptides from domain-N and domain-C indicate that these two domains can bind simultaneously to a single molecule of calmodulin. Multiple contacts between the gamma-subunit and calmodulin (delta-subunit), as indicated by our data, may help to explain why strongly denaturing conditions are required to dissociate these two subunits, whereas complexes of calmodulin with most other target enzymes can be readily dissociated by merely lowering Ca2+ to submicromolar concentrations. Comparison of the sequences of the two calmodulin-binding domains in the gamma-subunit of phosphorylase kinase with corresponding regions in troponin I indicates similarities that may have functional and evolutionary significance.