Macrophage-Dependent Cytoplasmic Transfer during Melanoma Invasion In Vivo

Interactions between tumor cells and tumor-associated macrophages play critical roles in the initiation of tumor cell motility. To capture the cellular interactions of the tumor microenvironment with high-resolution imaging, we directly visualized tumor cells and their interactions with macrophages in zebrafish. Live imaging in zebrafish revealed that macrophages are dynamic, yet maintain sustained contact with tumor cells. In addition, the recruitment of macrophages to tumor cells promotes tumor cell dissemination. Using a Cre/LoxP strategy, we found that macrophages transfer cytoplasm to tumor cells in zebrafish and mouse models. Remarkably, macrophage cytoplasmic transfer correlated with melanoma cell dissemination. We further found that macrophages transfer cytoplasm to tumor cells upon cell contact in vitro. Thus, we present a model in which macrophage/tumor cell contact allows for the transfer of cytoplasmic molecules from macrophages to tumor cells corresponding to increased tumor cell motility and dissemination.

Inguinal herniorrhaphy in young infants: perianesthetic complications and associated preanesthetic risk factors

STUDY OBJECTIVES

(1) To prospectively observe and tabulate all perianesthetic complications in young infants undergoing herniorrhaphy with general anesthesia and (2) to identify all major postnatal complications and determine which, if any, might be significant risk factors for perianesthetic complications.

DESIGN

Prospective case control study.

SETTING

Columbus, Ohio, Children's Hospital, a teaching and tertiary referral center.

PATIENTS

One hundred two consecutive infants 60 weeks postconceptual age (PCA) or younger undergoing herniorrhaphy with general anesthesia.

INTERVENTIONS

None

MEASUREMENTS AND MAIN RESULTS

All perianesthetic complications occurring during anesthesia, in the postanesthesia care unit (PACU), during the remaining hospital stay, and within 30 days of anesthesia were recorded, and a detailed postnatal history was compiled. Fifty-five percent of 60 preterm infants [37 weeks gestational age (GA) or younger] and 50% of 42 term infants (older than 37 weeks GA) experienced at least one perianesthetic complication. Following discharge from the PACU, in-house complications were confined to the preterm group. Significant risk factors included a history of apnea, bradycardia, and ventilatory support for at least 24 hours after birth, mainly for respiratory distress syndrome.

CONCLUSIONS

In a teaching hospital, prospectively observed perianesthetic complications can occur in more than 50% of infants 60 weeks PCA or younger undergoing herniorrhaphy with inhalation anesthesia. Infants younger than 49 weeks PCA with a significant preanesthetic risk factor should be monitored overnight for apnea and bradycardia.

Negative pressure pulmonary oedema: a potential hazard of muscle relaxants in awake infants

We report two cases of healthy infants who were given an IV intubating bolus of a nondepolarizing muscle relaxant (0.1 mg.kg-1 vecuronium) at the beginning of an inhalational induction of anaesthesia. Shortly after the introduction of low concentrations of gaseous agents, both infants exhibited airway obstruction although inspiratory muscle activity was still vigorous. The airway obstruction was due to approximation of the tongue to the posterior pharyngeal wall, and was easily corrected by insertion of an oral airway. The infants immediately exhibited fulminant pulmonary oedema, which responded to conventional therapy. It is postulated that paralysis of glossal muscles occurred prior to diaphragmatic paralysis, creating upper airway obstruction while preserving inspiratory muscle activity. This can rapidly lead to negative pressure pulmonary oedema in the small infant. Meticulous attention to the maintenance of an unobstructed upper airway is required if muscle relaxants are administered to the awake infant.

Negative pressure pulmonary oedema secondary to airway obstruction in an intubated infant

We report the case of a healthy one-month-old male infant who underwent an uneventful endotracheal anaesthetic for hernia repair. During transport to the recovery room (a less than 30 second trip), the endotracheal tube in the spontaneously breathing infant became obstructed, possibly due to impaction of the tip in the right main bronchus. Restoration of the airway was followed by fulminant pulmonary oedema. Several days of vigorous respiratory and pharmacologic therapy were required for resolution of the infant's respiratory distress. We review other reported cases of acute airway obstruction associated with pulmonary oedema in children and briefly describe the proposed mechanisms. The difficulties of gauging proper endotracheal tube depth in the infant are noted. This case report demonstrates the importance of continuous monitoring during patient transport to the recovery room.