Electrophysiological classification of P2X7 receptors in rat cultured neocortical astroglia

BACKGROUND AND PURPOSE

P2X7 receptors are ATP-gated cation channels mediating important functions in microglial cells, such as the release of cytokines and phagocytosis. Electrophysiological evidence that these receptors also occur in CNS astroglia is rare and rather incomplete.

EXPERIMENTAL APPROACH

We used whole-cell patch-clamp recordings to search for P2X7 receptors in astroglial-neuronal co-cultures prepared from the cerebral cortex of rats.

KEY RESULTS

All the astroglial cells investigated responded to ATP with membrane currents, reversing around 0 mV. These currents could be also detected in isolated outside-out patch vesicles. The results of the experiments with the P2X [alpha,beta-methylene ATP and 2'-3'-O-(4-benzoyl) ATP] and P2Y receptor agonists [adenosine 5'-O-(2-thiodiphosphate), uridine 5'-diphosphate, uridine 5'-triphosphate (UTP) and UDP-glucose] suggested the involvement of P2X receptors in this response. The potentiation of ATP responses in a low divalent cation or alkaline bath, but not by ivermectin, made it likely that a P2X7 receptor is operational. Blockade of the ATP effect by the P2X7 antagonists Brilliant Blue G, calmidazolium and oxidized ATP corroborated this assumption.

CONCLUSIONS AND IMPLICATIONS

Rat cultured cortical astroglia possesses functional P2X7 receptors. It is suggested that astrocytic P2X7 receptors respond to high local ATP concentrations during neuronal injury.

Evaluation and management of children younger than two years old with apparently minor head trauma: proposed guidelines

OBJECTIVE

In children <2 years old, minor head trauma (HT) is a common injury that can result in skull fracture and intracranial injury (ICI). These injuries can be difficult to detect in this age group; therefore, many authors recommend a low threshold for radiographic imaging. Currently, no clear guidelines exist regarding the evaluation and management of head-injured infants. We sought to develop guidelines for management based on data and expert opinion that would enable clinicians to identify children with complications of HT and reduce unnecessary imaging procedures. METHODS.

EVIDENCE

References addressing pediatric HT were generated from a computerized database (Medline). The articles were reviewed and evidence tables were compiled. EXPERT PANEL: The multidisciplinary panel was comprised of nine experts in pediatric HT.

CONSENSUS PROCESS

A modified Delphi technique was used to develop the guidelines. Before the one meeting, panel members reviewed the evidence and formulated answers to specific clinical questions regarding HT in young children. At the meeting, guidelines were formulated based on data and expert consensus.

RESULTS

A management strategy was developed that categorizes children into 4 subgroups, based on risk of ICI. Children in the high-risk group should undergo a computed tomography (CT) scan. Those in the intermediate risk group with symptoms of possible ICI should either undergo CT scan or observation. Those in the intermediate risk group with some risk for skull fracture or ICI should undergo CT and/or skull radiographs or observation. Those in the low-risk group require no radiographic imaging.

CONCLUSIONS

We have developed a guideline for the evaluation of children <2 years old with minor HT. The effect of these guidelines on clinical outcomes and resource utilization should be evaluated.

Pediatric Emergency Medicine (PEM) fellowship: essentials of a three-year academic curriculum. Three-Year Academic Subcommittee of the PEM Fellowship Committee of the Section of Emergency Medicine, American Academy of Pediatrics

This committee of fellowship directors has proposed guidelines for an academic curriculum for training fellows in PEM. The curriculum should be modified to each unique program, but is based on current expectation of the American Board of Pediatrics and the ACGME for graduate education. This is the first PEM academic curriculum document in publication. Ongoing refinement and adaptation based on feedback from fellows and directors is essential to provide the best fellowship experience to our trainees. The proposed curriculum is also subject to further change as more details are given for ACGME approval of the fellowship programs.

Blunt pediatric laryngotracheal trauma: case reports and review of the literature

Blunt laryngotracheal trauma can be a life-threatening event. Two cases of isolated blunt laryngotracheal trauma in pediatric patients are presented. One case involves a 12-year-old mate who suffered isolated tracheal trauma from a fall. He developed respiratory distress and required a tracheostomy. Intraoperatively he was noted to have a thyroid cartilage fracture. The other case involves a 14-year-old female who was kicked in the neck by a horse. After unsuccessful intubation attempts that completed a tracheal transection, she required an emergency cricothyrotomy and a subsequent tracheostomy. The diagnosis, differential diagnosis, associated injuries, and treatment options for blunt laryngeal trauma are reviewed.