Pax3 mRNA is decreased in the hearts of rats with experimental diaphragmatic hernia

Rats with nitrofen-induced congenital diaphragmatic hernia (CDH) have heart hypoplasia and cardiovascular malformations. The mechanism of action of nitrofen involves changes in neural crest signaling. Pax3 function is required for cardiac neural crest cells to complete their migration to the developing heart. The aim of this study was to examine whether Pax3 expression is changed at two gestational endpoints in rat embryos or fetuses exposed to nitrofen. On day E9.5 of gestation, pregnant rats received either 100 mg of nitrofen (n=10) or vehicle alone (control, n=10). The fetuses were recovered on E15 or E21. Their hearts were dissected out and weighed. Pax3 mRNA expression was determined by real-time polymerase chain reaction. We used two-tailed Students t-tests to compare groups, with a threshold of significance of p<0.05. Compared with controls, nitrofen-exposed fetuses had heart hypoplasia in terms of heart/body weight ratio (0.62±0.10% vs. 0.77±0.17%, p<0.05). Pax3 mRNA expression in the heart was significantly decreased on E15 in nitrofen-treated embryos (32.94±17.11 U vs. 55.09±11.56 U, p<0.05), and it was still decreased, although not significantly, in the hearts of nitrofen-exposed fetuses recovered on E21 (15.67±5.56 U vs. 20.51±5.92 U, not significant). In conclusion, Pax3 is underexpressed in the hearts of nitrofen-exposed embryonal rats before the end of gestation. The mechanism of action of Pax3 should be further investigated because it could be one of the targets for future prenatal transplacental intervention.Paper presented at the XVIIth International Symposium of Pediatric Surgical Research, Liverpool, United Kingdom, 1–2 October, 2004.     

Incorrect instruction in the use of the Valsalva manoeuvre for paroxysmal supra-ventricular tachycardia is common

Objective: Success rates for the Valsalva manoeuvre (VM) in treatment of paroxysmal supraventricular tachycardia (SVT) vary with performance technique. This study aimed to assess whether ED doctors instruct their patients to perform the recommended VM technique (supine position for 15 s). Methods: A multicentre, observational study of 35 ED registrars and 17 emergency physicians. Each doctor was asked to describe how he/she would instruct a patient in SVT to perform the VM. Results: Only five (9.6%) doctors would position their patient correctly and 31 (59.6%) would incorrectly instruct their patient to assume a sitting or semirecumbent position. Only five (9.6%) doctors would give specific instructions to blow for at least 15 s and 34 (65.4%) would instruct their patient to blow ‘as long as you can’. Only four (7.4%) doctors would use a sphygmomanometer to measure intrathoracic pressure during the VM. There were no significant differences (P > 0.05) between the registrar and physician group responses for any study endpoint. Conclusion: Few ED doctors correctly instruct their patients in the VM technique recommended for management of SVT. Hence, maximal vagal tone and SVT conversion rates may not be achieved in many cases. The use of the recommended VM technique is encouraged.     

Assessment of tracheal intubation in children after induction with propofol and different doses of remifentanil

Tracheal intubating conditions were assessed in 112 children after induction of anaesthesia with propofol and remifentanil 1.0, 2.0 or 3.0 micro g.kg-1. Subjects in a control group were given propofol and mivacurium 0.2 mg.kg-1. Haemodynamic and respiratory parameters were recorded. Plasma catecholamine levels were measured in a subgroup of 40 children. Intubating conditions were acceptable in 14/28 (50%), 18/26 (69%) and 22/27 (82%) in those subjects given remifentanil 1.0, 2.0 or 3.0 micro g.kg-1, respectively, and in 27/28 (96%) of the control group. Intubating conditions in subjects given remifentanil 3.0 micro g.kg-1 were better than in those given remifentanil 1.0 micro g.kg-1 (p < 0.05). There were no significant differences in intubating conditions between those given remifentanil 3.0 micro g.kg-1 and the control group. Systolic blood pressure and heart rate increased in response to tracheal intubation in subjects given remifentanil 1.0 micro g.kg-1 and in the control group (p < 0.05). Time to resumption of spontaneous respiration was prolonged in subjects given remifentanil 3.0 micro g.kg-1 (p < 0.001). In conclusion, remifentanil 2 micro g.kg-1 provides acceptable intubating conditions and haemodynamic stability without prolonging the return of spontaneous respiration.     

Laryngeal embryonal rhabdomyosarcoma: a case of cervical metastases 13 years after treatment and a 25-year review of existing literature

Rhabdomyosarcoma is the most common soft tissue sarcoma in childhood, the majority of which are of the embryonal rhabdomyosarcoma (ER) variety. Present day treatment protocols involve a combination of aggressive surgery, chemotherapy, and radiation therapy. Embryonal rhabdomyosarcoma of the larynx is rare and unlike ER of other regions exhibits excellent response to multimodality treatment without the need for extensive surgery. We report a case of cervical metastases in a 29-year-old man 13 years after treatment of his laryngeal ER. To our knowledge, this is the first reported case of late neck metastases in ER of the larynx and the second reported case of delayed presentation of recurrent disease. A 25-year review of all published reports of ER of the larynx was conducted that highlights the move toward organ preservation with the multimodality treatment protocols. Embryonal rhabdomyosarcoma of the larynx is highly responsive to combination chemoradiotherapy, allowing for excellent cure rates without the need for extensive surgery. Late relapses warrant long-term follow-up.     

Long-term results of 100 consecutive comprehensive neck dissections: implications for selective neck dissections

OBJECTIVE: The optimal surgical procedure for the neck in patients with squamous head and neck cancers is controversial. Selective neck dissections have replaced modified radical neck dissections as the procedure of choice for the clinically negative (N0) neck and are now being considered for patients with early-stage neck disease. We report the long-term local recurrence rates in 100 consecutive patients undergoing a radical or modified radical neck dissection for clinically positive (N+) and N0 neck disease and review comprehensively the literature reporting and comparing regional control rates for both neck dissection types. PATIENTS: The clinical records of 100 consecutive patients who underwent a comprehensive neck dissection (levels I-V) for squamous head and neck cancers with a minimum of a 2-year follow-up were retrospectively reviewed for primary site of disease, clinical and pathologic neck status, histopathologic grade, neck dissection type, and the site and time of recurrence. RESULTS: Complete data were available for 97 patients on whom 99 neck dissections were performed. Three patients died from unknown causes. Seventy-six patients with N+ disease underwent a therapeutic neck dissection, while 24 patients with clinically N0 disease underwent an elective dissection. The overall neck recurrence rate in patients with controlled primary disease was 7%. The neck or regional failure rate for patients completing the recommended adjuvant radiotherapy was 4%. Six (25%) of 24 patients with clinically N0 disease had occult metastases. The recurrence rate for this group was 4%. CONCLUSION: Further study is needed to determine the optimal surgical management of the N0 and limited N+ neck.     

The Leg Drop Pendulum Test performed under general anesthesia in spastic cerebral palsy

The general aim of this study was to examine the stiffness and damping characteristics (rate at which oscillations diminish) of limbs of a small population of patients with spastic cerebral palsy (CP) during the Leg Drop Pendulum Test while under general anesthesia and to compare them with patients without CP, both awake and under similar anesthetized conditions. To facilitate a quantitative comparison the authors defined a set of parameters that reflect the stiffness and damping of limbs with spasticity under general anesthesia. To give these parameters more meaning a similar set was constructed for children without disabilities under conditions of normal wakefulness and under anesthesia. The test population of 10 patients with spasticity ranged in age from 4 to 19 years and had a mean age of 10 years 9 months (SD 5 years 10 months); there were four females and six males. The control population consisted of eight patients without disabilities who ranged in age from 7 to 19 years with mean age of 13 years 9 months (SD 3 years 3 months); there were six females and two males. To even out the populations, two limbs from the non-affected sides of two patients with hemiplegic spasticity (both female) were used in the control group. The Leg Drop Pendulum Test was administered to 10 limbs with spastic CP and 10 control limbs under general anesthesia. The two test populations were chosen from patients who were previously scheduled to undergo surgery. Two measures compared limbs of those under anesthetic with those under alert conditions: the damped natural frequency and the damping ratio. The natural frequency is the frequency at which a pendulum oscillates as it comes to rest; the damping ratio is a measure of how quickly the oscillations diminish. In spasticity, active muscle tone disappeared under anesthesia. In both groups the underlying biomechanics of the limb varied considerably. In controls the variation seemed to be growth related.