Sleep architecture in Pierre-Robin sequence: The effect of mandibular distraction osteogenesis.

INTRODUCTION: Pierre-Robin Sequence (PRS), a triad of micro/retrognathia, glossoptosis, and upper airway obstruction, usually in conjunction with a cleft palate is frequently associated with significant morbidity. Mandibular distraction osteogenesis (MDO) is an effective treatment modality to address retroglossal upper airway obstruction by increasing the anterior-posterior diameter of the infant airway. Although MDO has been shown to improve the apnea-hypopnea index (AHI) in children with PRS, the consequences of MDO on other aspects of infant sleep, including hypercapnea, hypoxia, the REM to Non-REM ratio, as well as its effect on central and mixed apneas has not been investigated with an adequate sample size. OBJECTIVE: To characterize the effect of MDO on key components of sleep architecture in infants with PRS. METHODS: Charts from 32 infants with PRS that were addressed with MDO at our tertiary-care children's hospital were retrospectively reviewed. Of these, 26 infants (57.7% male; mean age = 4.1 weeks, SD = 5.0) had pre- and post-operative polysomnograms (PSG). Paired samples t-tests were used to compare pre- and post- MDO sleep architecture mean score differences. RESULTS: Among the 26 infants, 73.1% demonstrated severe pre-MDO sleep apnea (AHI > 10). Several aspects of sleep architecture were found to improve post-operatively. Significant improvements were found in AHI (30.3 vs. 8.7; t = 4.1, p < 0.001), obstructive apneas (79.3 vs. 5.8; t = 4.0, p < 0.001), hypopneas (48.1 vs. 22.1; t = 2.2, p = 0.040), time spent below 90% SpO2 (3.9% vs. 0.7%; t = 3.3, p = 0.003), and lowest SpO2 nadir (75.4% vs. 82.9%; 3.4, p = 0.002). In addition, a marginally significant improvement was found for mixed apnea (6.3 vs. 1.6; t = 1.99, p = 0.058). CONCLUSION: MDO improves several sleep architecture parameters in this sample of infants with PRS. Statistically significant improvement was seen in obstructive apneas, hypopneas, AHI, obstructive AHI, and several indicators of hypoxia during sleep.

Chloral hydrate for sedation of children with asthma during dental treatment.

AIM: We hypothesised that chloral hydrate is safe and effective for sedation during dental treatments for children with mild asthma. We evaluated the safety and efficacy of chloral hydrate by measuring changes in heart rate (HR), transcutaneous oxygen saturation, (SpO2), asthma score, behaviour, types and frequency of adverse reactions associated with chloral hydrate were assessed throughout treatment. MATERIALS AND METHODS: Children (<10 years old) with mild asthma undergoing dental treatments received a single 65 mg/kg oral dose of chloral hydrate liquid 1 hour prior to treatment in an open label trial. Heart rate (HR), SpO2, asthma score, behaviour, types and frequency of adverse reactions associated with chloral hydrate were assessed throughout treatment. Asthma score was obtained before and after treatment. Thirty minutes after treatment, SpO2, HR, and level of consciousness was assessed. RESULTS: Twenty four children were enrolled and 92% (22/24) recovered from sedation without respiratory depression. Two experienced mild respiratory depression related to chloral hydrate. Asthma was not a contributing factor as they did not experience wheezing, cough, tachypnoea, or retractions. Inhaled nitrous oxide supplemented chloral hydrate sedation in 63% (15/24) children to achieve effective cooperation. Three children had a SpO2 <95% (2 during treatment, 1 during recovery). CONCLUSION: Chloral hydrate 65 mg/kg administered a as single oral dose appears to be safe with respect to disease exacerbation for children with mild asthma undergoing dental treatment. Due to ineffective sedation and mild respiratory depression associated with chloral hydrate, newer, easily titrated medications, such as midazolam, may offer advantages.

Analysis of the mechanism by which melatonin inhibits human eosinophil peroxidase.

BACKGROUND AND PURPOSE: Eosinophil peroxidase (EPO) catalyses the formation of oxidants implicated in the pathogenesis of various respiratory diseases including allergy and asthma. Mechanisms for inhibiting EPO, once released, are poorly understood. The aim of this work is to determine the mechanisms by which melatonin, a hormone produced in the brain by the pineal gland, inhibits the catalytic activity of EPO. EXPERIMENTAL APPROACH: We utilized H2O2-selective electrode and direct rapid kinetic measurements to determine the pathways by which melatonin inhibits human EPO. KEY RESULTS: In the presence of plasma levels of bromide (Br-), melatonin inactivates EPO at two different points in the classic peroxidase cycle. First, it binds to EPO and forms an inactive complex, melatonin-EPO-Br, which restricts access of H2O2 to the catalytic site of the oxidation enzyme. Second, melatonin competes with Br- and switches the reaction from a two electron (2e-) to a one electron (1e-) pathway allowing the enzyme to function with catalase-like activity. Melatonin is a bulky molecule and binds to the entrance of the EPO haem pocket (regulatory sites). Furthermore, Br- seems to enhance the affinity of this binding. In the absence of Br-, melatonin accelerated formation of EPO Compound II and its decay by serving as a 1e- substrate for EPO Compounds I and II. CONCLUSIONS AND IMPLICATIONS: The interplay between EPO and melatonin may have a broader implication in the function of several biological systems. This dual regulation by melatonin is unique and represents a new mechanism for melatonin to control EPO and its downstream inflammatory pathways.

Effect of zinc supplementation on respiratory tract infections in children with cystic fibrosis.

Zinc (Zn) has significant anti-oxidant and anti-inflammatory activity. Zn deficiency can occur in subsets of patients with cystic fibrosis (CF) especially those with malabsorption and impaired growth. Although supplemental Zn has significantly reduced infections in various disorders, its efficacy has not been thoroughly investigated in CF. We performed a double blind placebo controlled pilot study to investigate the effect of daily 30 mg elemental Zn for 1 year on the rate of respiratory tract infections (RTIs), use of antibiotics and plasma cytokines in 26 children with CF (ages 7-18 years). Plasma Zn, Cu, inflammatory cytokines and ex vivo generation of IL-2 were measured at baseline and at the end of the study. The number of days of oral antibiotics was lower in Zn treated patients compared to placebo (P = 0.05). However, compared to placebo, the effect of Zn was greater in patients who exhibited low plasma Zn at baseline (P = 0.02) than those who had plasma Zn levels identical to normal subjects (P = 0.55). Zn supplementation was marginally effective in reducing percentage increase in plasma IL-6 and IL-8 while increasing the percentage change in ex vivo generation of IL-2 in isolated mononuclear cell. In conclusion, oral intake of 30 mg/day of Zn reduced the number of days of oral antibiotics used to treat RTIs in children with CF. A higher daily Zn dose may be needed to decrease RTIs and modify immune responses.

A study on birth weight in a teaching-referral hospital, Gondar, Ethiopia.

OBJECTIVE: To determine the pattern of birth weight of neonates in a teaching-referral hospital and to identify some epidemiological parameters associated with them. STUDY DESIGN: A prospective descriptive study, using a pre-prepared Questionnaire, on all deliveries in the maternity ward during one year. SETTING: The Gondar College of Medical Sciences Hospital, Gondar, north western Ethiopia. RESULTS: 810 consecutive hospital births were recorded. The mean birth weight of 373 full term singleton neonates was 3 003g (SD600). The incidence of low birth weight (birth weight < 2 500 g) and very low birth weight (birth weight < 1 500 g) was 15.4% and 2.6% respectively. The mean birth weight and percentage of low birth weight were significantly different in both sexes (p < 0.0001). The birth weight increases as parity and length of gestation increase. As maternal age and maternal height increase, so do the birth weights of their neonates in this study. Total house hold income, maternal education and antenatal care use were not found to influence the mean birth weight in this study. CONCLUSION: The mean birth weight and prevalence of low birth weight are similar to other reports from Ethiopia. It was observed that as maternal age, maternal height, parity and length of gestation increase, the mean birth weight increase in this study.

Granular cell tumor of the bronchus.

Persistent atelectasis and recurrent pneumonia in the same location should raise suspicion of congenital anomalies or obstructing lesions of the bronchus leading to the affected area. We present an 8-year-old black female with a history of recurrent fever, cough, atelectasis of the right middle and lower lobes, and weight loss for several months. Flexible bronchoscopy revealed a polypoid mass obstructing the bronchus intermedius. Biopsy of the neoplasm demonstrated a granular cell tumor (GCT). The patient had a lobectomy of the right lower and middle lobes. She had no recurrence of the tumor after several years of follow-up.

Quality of life as a treatment outcome in patients with cystic fibrosis.

We attempted to determine the responsiveness and validity of the Quality of Well-Being (QWB) scale in 20 consecutive children and adolescents with cystic fibrosis. The QWB score was determined for 6-day periods immediately before and after hospital admission, and at 6- and 12-month follow-up. With the instrument's scale of zero-1, responsiveness was indicated by significant changes in QWB score (0.09), physical (0.019), social (0.021), and symptom-problem complexes (0.04) domains, and all pulmonary function tests from before to after treatment of an acute exacerbation. Only the symptom-problem complex domain significantly changed from after treatment to 6- and 12-month follow-up. Validity was shown by significant correlations between before and after QWB scores and forced vital capacity (r=0.476), residual volume total lung capacity ratio (r=0.452), forced expiratory volume in 1 second (r=0.358), and forced expiratory flow between 25% and 75% of vital capacity (r=0.35).

Comparison of 2-channel and 4-channel pneumograms.

To determine whether the addition of air flow and O2 saturation (SaO2) channels improves sensitivity of the pneumogram in identifying cardiorespiratory pattern abnormalities, 2- and 4-channel pneumograms (PG-2 and PG-4) were simultaneously recorded in 91 consecutive infants. Forty-one infants (45%) had cardiorespiratory symptoms, and 50 were asymptomatic. Pneumograms were considered abnormal for any of the following: apnea greater than or equal to 20 seconds, heart rate less than 80 bpm for greater than 5 seconds in preterm and less than 60 bpm in full-term infants (bradycardia), shorter apnea with bradycardia or desaturation, periodic breathing greater than 7% of total sleep time in preterm and greater than 4% in full-term infants, or SaO2 less than 85% for greater than 5 seconds. Both recordings were normal in 72% of infants and abnormal in 24%. In only 4% were the PG-4 abnormal when the PG-2 were normal, in all instances due to minimum SaO2 levels of 77-84% for 5-19 seconds associated with central apnea of intermediate duration (three infants) or with mixed apnea. The difference in frequency of abnormal results between the PG-2 and PG-4 recordings was not statistically significant (X2). In conclusion, although PG-4 do increase the scope of physiological information obtained in infants with cardiorespiratory events, this short-term study does not establish whether this increase results in any long-term benefits. Further, at least in this number and these types of at-risk infants, PG-4 do not improve the sensitivity of cardiorespiratory recordings for detecting abnormalities.