Pediatric Down Syndrome Upper Airway Stimulation: Patient Selection and Post-Implantation Optimization

OBJECTIVE

The Food and Drug Administration recently approved upper airway stimulation (UAS) for children with Down Syndrome and persistent obstructive sleep apnea who meet certain inclusion and exclusion criteria. Although there is a robust experience with this therapy in the adult population, established protocols used in adults are not directly transferrable to a complex pediatric population. This review aims to combine the protocols from several institutions for patient selection and postimplantation optimization, including a protocol for Drug-Induced Sleep Endoscopy in children with Down Syndrome, preactivation threshold measurements, device titration, and follow-up sleep studies.

STUDY DESIGN

Expert panel development of best Practice algorithm.

SETTING

Multi-institutional investigator review.

METHODS

An expert panel was assembled of pediatric otolaryngologists with extensive experience in hypoglossal nerve stimulation in children with Down Syndrome. Thirty statements were created during an initial drafting session. A modified Delphi method was used assess consensus among the panel.

RESULTS

After 2 rounds of Delphi surveys, 29 statements met criteria for consensus. One statement did not meet consensus. The statements were grouped into several categories to facilitate presentation.

CONCLUSIONS

A standardized approach to UAS for children with Down Syndrome must take into account the unique challenges inherent to treating a complex pediatric population with a high rate of sensory processing disorders. This expert panel has met consensus on several statements that will guide clinicians as this novel therapy is adopted.

Residual OSA in Down syndrome: does body position matter?

STUDY OBJECTIVES

To examine children with Down syndrome with residual obstructive sleep apnea (OSA) to determine if they are more likely to have positional OSA.

METHODS

A retrospective chart review of children with Down syndrome who underwent adenotonsillectomy at a single tertiary children's hospital was conducted. Children with Down syndrome who had a postoperative polysomnogram with obstructive apnea-hypopnea index (OAHI) > 1 event/h, following adenotonsillectomy with at least 60 minutes of total sleep time were included. Patients were categorized as mixed sleep (presence of ≥ 30 minutes of both nonsupine and supine sleep), nonsupine sleep, and supine sleep. Positional OSA was defined as an overall OAHI > 1 event/h and a supine OAHI to nonsupine OAHI ratio of ≥ 2. Group differences are tested via Kruskal-Wallis test for continuous variables and Fisher's exact tests for categorical.

RESULTS

There were 165 children with Down syndrome who met inclusion criteria, of which 130 individuals had mixed sleep. Patients who predominately slept supine had a greater OAHI than mixed and nonsupine sleep (P = .002). Sixty (46%) of the mixed-sleep individuals had positional OSA, of which 29 (48%) had moderate/severe OSA. Sleeping off their backs converted 14 (48%) of these 29 children from moderate/severe OSA to mild OSA.

CONCLUSIONS

Sleep physicians and otolaryngologists should be cognizant that the OAHI may be an underestimate if it does not include supine sleep. Positional therapy is a potential treatment option for children with residual OSA following adenotonsillectomy and warrants further investigation.

CITATION

Lackey TG, Tholen K, Pickett K, Friedman N. Residual OSA in Down syndrome: does body position matter? J Clin Sleep Med. 2023;19(1):171-177.

Diagnosis and management of sleep disorders in Prader-Willi syndrome

Clinical experience and a growing body of evidence suggest that sleep disturbances are common in people with Prader-Willi syndrome (PWS). PWS is a rare neuroendocrine disorder characterized by early hypotonia and feeding difficulties; developmental delays; endocrinopathies; and behavioral concerns, especially rigidity, anxiety, and behavioral outbursts. PWS is also characterized by decreased resting energy expenditure and transition to hyperphagia and obesity. We propose that, for many people with PWS, clinical diagnosis and management of sleep disorders is an unmet need. We present current information to suggest disordered sleep is a significant burden for individuals with PWS and often overlooked. While central and obstructive sleep apnea are more widely recognized in PWS, other sleep disorders have increasingly gained recognition, including hypersomnia, narcolepsy-like phenotypes, and insomnia. Sleep disorders can impact behavior, cognition, and quality of life and health for individuals with PWS. Our goal is to bring sleep disorders to the forefront of therapeutic intervention for patients with PWS. This paper presents a review of the literature and recommendations for clinical practice based on published research and our clinical experience as sleep specialists, geneticists, psychiatrists, pediatricians, otolaryngologists, and pulmonologists with extensive experience with this patient population. We recommend that management of sleep be considered an integral part of successful medical management of PWS. Further research concerning sleep problems in PWS is urgently needed to develop best practices and work toward a consensus statement for medical management to meet the needs of people with PWS.

CITATION

Duis J, Pullen LC, Picone M, et al. Diagnosis and management of sleep disorders in Prader-Willi syndrome. J Clin Sleep Med. 2022;18(6):1687-1696.

Airway obstruction and inflammation on combined bronchoscopy in children with Down syndrome

OBJECTIVE

To characterize the upper and lower airway findings in children with Down syndrome and chronic respiratory symptoms, based on evaluation by flexible bronchoscopy (FB) with bronchoalveolar lavage and microlaryngoscopy with bronchoscopy (MLB).

STUDY DESIGN

A retrospective review was conducted of children with Down syndrome aged 1 month to 17 years, who underwent both FB and MLB within a 1-year timeframe between 2010 and 2019 at Children's Hospital Colorado. Anatomic airway findings are reported as frequencies within the cohort. Bronchoalveolar lavage fluid (BALF) culture results, cell differential, and cytopathology are reported as frequencies or mean ± standard deviation. BALF results were compared between children with and without dysphagia documented on a recent swallow evaluation.

RESULTS

Overall, 168 children with Down syndrome were included, with median age of 2.1 years (interquartile range: 0.9-5.1 years). At least one abnormal airway finding was recorded in 96% of patients and 46% had at least three abnormal findings. The most common findings included tracheomalacia (39% FB; 37% MLB), subglottic stenosis (35% MLB), pharyngomalacia (32% FB), and laryngomalacia (16% FB; 30% MLB). Comparison of BALF based on dysphagia status showed that children with dysphagia had more frequent cultures positive for mixed upper respiratory flora (76% vs. 47%, p = 0.004) and a higher percentage of neutrophils (20% vs. 7%, p = 0.006).

CONCLUSION

Abnormal findings for FB and MLB are common in children with Down syndrome and chronic respiratory symptoms, and performing the procedures together may increase the diagnostic yield.

Persistent OSA in obese children: does body position matter?

STUDY OBJECTIVES

The objective of this study was to determine if positional therapy is a viable treatment alternative for obese children with persistent obstructive sleep apnea (OSA).

METHODS

A retrospective review was performed of children who underwent an adenotonsillectomy for OSA from 2014 to 2017. Children were included if they had a body mass index ≥ 95th percentile and underwent a postoperative polysomnogram. Subjects fell into one of three categories: mixed sleep (the presence of ≥ 30 minutes of both nonsupine and supine sleep), nonsupine sleep, and supine sleep. Cure was defined as an OSA/apnea-hypopnea index of < 1 events/h. Paired t tests were used to assess the differences, and a linear model adjusting for obesity class, age at procedure, and sex was performed to assess the differences between nonsupine and supine sleep.

RESULTS

There were 154 children who met the inclusion criteria. Using a paired t test, supine sleep position had a significantly higher average OSA/apnea-hypopnea index (7.9 events) compared with nonsupine (OSA/apnea-hypopnea index of 4.1); P value was < .01 for the 60 children with mixed sleep. Forty-three children had predominantly nonsupine sleep and 33 predominantly supine sleep, and a McNemar's test comparing these children showed that those sleeping in the nonsupine position were significantly more likely to be cured than those in the supine position (P < .001).

CONCLUSIONS

Sleep physicians and otolaryngologists should be cognizant of positional treatment when consulting with families and note that the postoperative polysomnography may be inaccurate if it does not include supine sleep. Positional therapy as a potential treatment option for obese children with persistent OSA after adenotonsillectomy warrants further investigation.

Effect of adenotonsillectomy in children with obstructive sleep apnea and major psychiatric disorders on obstructive apnea-hypopnea index and Epworth Sleepiness Scale scores

STUDY OBJECTIVES

This study evaluates the effectiveness of adenotonsillectomy in the treatment of obstructive sleep apnea in children with major psychiatric disorders as measured by polysomnography and the Epworth Sleepiness Scale (ESS) at a tertiary children's hospital. Adults with major psychiatric disorders often have higher rates of obstructive sleep apnea and decreased response to treatment. The goal was to determine if children with serious mental illness had outcomes similar to their adult counterparts.

METHODS

A retrospective chart review was undertaken to identify children with obstructive sleep apnea and major psychiatric disorders who underwent adenotonsillectomy as part of their treatment for obstructive sleep apnea and had undergone preoperative and postoperative polysomnography as well as ESS. A multivariable model was run for each of the postoperative outcomes (ESS, obstructive apnea-hypopnea index, or body mass index percentile), adjusting for their respective preoperative value, age, and group.

RESULTS

There were 34 patients who qualified for this study and who were matched with 66 controls. There was no significant difference between the 2 groups in terms of change in ESS, obstructive apnea-hypopnea index, or body mass index percentile, both before and after adjusting for age. The only significant findings were that preoperative ESS and body mass index percentile were predictive of postoperative ESS and body mass index percentile for both groups.

CONCLUSIONS

Children with psychiatric disorders in our institution respond to surgical management of obstructive sleep apnea similar to pediatric controls without mental illness despite comorbidities and central-acting medications that may alter sleep.

Accuracy of point-of-care ultrasound by pediatric emergency physicians for testicular torsion

INTRODUCTION

Acute scrotum is a common presentation to the pediatric emergency department, and ultrasound is frequently used to narrow the differential diagnosis. Point-of-care ultrasound (POCUS) is increasingly used by urologists and emergency physicians and could potentially be used to detect pediatric testicular torsion.

OBJECTIVES

This study aimed to determine the accuracy of POCUS by pediatric emergency physicians in diagnosing testicular torsion and the agreement between point-of-care ultrasound and final diagnosis for other causes of acute scrotum.

STUDY DESIGN

A chart review of patients presenting to the study emergency department who received POCUS by a pediatric emergency physician, as well as radiology department ultrasound and/or surgery, was performed. Charts were reviewed for POCUS diagnoses, final diagnoses, and imaging time metrics.

RESULTS

A total of 120 patients met study criteria, with 12 cases of testicular torsion. The diagnostic accuracy of POCUS for testicular torsion is described in the summary table. For all causes of acute scrotum, point-of-care ultrasound agreed with final diagnosis in 70% (95% confidence interval [CI] 62-78%) of cases, and more experienced point-of-care ultrasound users displayed higher agreement with final diagnosis. Point-of-care ultrasound results were generated a median of 73 min (Q1 = 51, Q3 = 112) before radiology department ultrasound results.

DISCUSSION

Scrotal POCUS performed by pediatric emergency physicians appears to be an accurate tool to detect testicular torsion in children with acute scrotum and saves time compared with radiology ultrasound. The study results may not be generalizable to hospitals without a multidisciplinary POCUS system for quality assurance and image sharing. Future work on POCUS for acute scrotum should investigate its impact on patient outcomes, cost-effectiveness, and family satisfaction.

CONCLUSION

Point-of-care ultrasound by pediatric emergency physicians is accurate for detecting testicular torsion in children with acute scrotum and could expedite diagnosis of this time-sensitive condition.

A2ML1 and otitis media: novel variants, differential expression, and relevant pathways

A genetic basis for otitis media is established, however, the role of rare variants in disease etiology is largely unknown. Previously a duplication variant within A2ML1 was identified as a significant risk factor for otitis media in an indigenous Filipino population and in US children. In this report exome and Sanger sequencing was performed using DNA samples from the indigenous Filipino population, Filipino cochlear implantees, US probands, Finnish, and Pakistani families with otitis media. Sixteen novel, damaging A2ML1 variants identified in otitis media patients were rare or low-frequency in population-matched controls. In the indigenous population, both gingivitis and A2ML1 variants including the known duplication variant and the novel splice variant c.4061 + 1 G>C were independently associated with otitis media. Sequencing of salivary RNA samples from indigenous Filipinos demonstrated lower A2ML1 expression according to the carriage of A2ML1 variants. Sequencing of additional salivary RNA samples from US patients with otitis media revealed differentially expressed genes that are highly correlated with A2ML1 expression levels. In particular, RND3 is upregulated in both A2ML1 variant carriers and high-A2ML1 expressors. These findings support a role for A2ML1 in keratinocyte differentiation within the middle ear as part of otitis media pathology and the potential application of ROCK inhibition in otitis media.

FUT2 Variants Confer Susceptibility to Familial Otitis Media

Non-secretor status due to homozygosity for the common FUT2 variant c.461G>A (p.Trp154∗) is associated with either risk for autoimmune diseases or protection against viral diarrhea and HIV. We determined the role of FUT2 in otitis media susceptibility by obtaining DNA samples from 609 multi-ethnic families and simplex case subjects with otitis media. Exome and Sanger sequencing, linkage analysis, and Fisher exact and transmission disequilibrium tests (TDT) were performed. The common FUT2 c.604C>T (p.Arg202∗) variant co-segregates with otitis media in a Filipino pedigree (LOD = 4.0). Additionally, a rare variant, c.412C>T (p.Arg138Cys), is associated with recurrent/chronic otitis media in European-American children (p = 1.2 × 10-5) and US trios (TDT p = 0.01). The c.461G>A (p.Trp154∗) variant was also over-transmitted in US trios (TDT p = 0.01) and was associated with shifts in middle ear microbiota composition (PERMANOVA p < 10-7) and increased biodiversity. When all missense and nonsense variants identified in multi-ethnic US trios with CADD > 20 were combined, FUT2 variants were over-transmitted in trios (TDT p = 0.001). Fut2 is transiently upregulated in mouse middle ear after inoculation with non-typeable Haemophilus influenzae. Four FUT2 variants-namely p.Ala104Val, p.Arg138Cys, p.Trp154∗, and p.Arg202∗-reduced A antigen in mutant-transfected COS-7 cells, while the nonsense variants also reduced FUT2 protein levels. Common and rare FUT2 variants confer susceptibility to otitis media, likely by modifying the middle ear microbiome through regulation of A antigen levels in epithelial cells. Our families demonstrate marked intra-familial genetic heterogeneity, suggesting that multiple combinations of common and rare variants plus environmental factors influence the individual otitis media phenotype as a complex trait.

Effect of patient and nurse ethnicity on emergency department analgesia for children with appendicitis in israeli government hospitals

BACKGROUND

Ethnicity is a risk factor for disparate Emergency Department (ED) analgesia. We aimed to explore ethnic variations in the administration of ED analgesia to children with acute appendicitis in Israeli government hospitals.

METHODS

Children discharged with an International Classification of Disease-Ninth Revision diagnosis of acute appendicitis between 2010 and 2015 were included. The association between patient ethnicity (Jewish, Arab) and analgesia administration (any, opioid) was assessed. Age, gender, triage category, pain score and time of arrival were tested as possible confounders. The effect of patient-nurse ethnic discordance (PNED) was examined.

RESULTS

Overall, 4714 children with acute appendicitis, 3520 Jewish and 1194 Arab, were cared for in the EDs; 1516 (32.2%) received any analgesia and 368 (7.8%) opioid analgesia. Stratified by pain score, no statistical differences were found in the administration of any or opioid analgesia between Jewish and Arab patients with either severe pain or moderate pain. In multivariate modelling adjusted for pain score and triage category, the rates of any analgesia for Arab and Jewish patients were 31.8% (95% CI, 30.9-32.6) and 36.5% (95% CI, 36.0-36.9), adjusted OR (aOR) = 1.16 (95% CI, 0.98-1.38), respectively. The rates of opioid analgesia for Arab and Jewish patients were 8.5% (95% CI, 8.2-8.9) and 7.9% (95% CI, 7.3-8.7), aOR = 0.77; (95% CI, 0.59-1.22), respectively. Jewish and Arab nurses treated proportionally fewer patients from the opposite ethnicity with any analgesia (p < 0.01).

CONCLUSION

Emergency Department analgesia was markedly low, and not associated with patient ethnicity. PNED was associated with decreased rates of analgesia.

SIGNIFICANCE

Emergency Department analgesia for children with acute appendicitis in Israeli government hospitals is markedly low. Patient-provider ethnic discordance may negatively influence the provision of analgesia. Significant efforts should be undertaken in order to increase analgesia provision rates and reduce social inequality.

American Academy of Sleep Medicine Position Paper for the Use of a Home Sleep Apnea Test for the Diagnosis of OSA in Children

INTRODUCTION

The purpose of this position paper is to establish the American Academy of Sleep Medicine's (AASM) position on the use of a home sleep apnea test (HSAT) for the diagnosis of obstructive sleep apnea (OSA) in children (birth to 18 years of age).

METHODS

The AASM commissioned a task force of 8 experts in sleep medicine to review the available literature on the use of an HSAT to diagnose OSA in children. The task force developed the position statement based on a thorough review of these studies and their clinical expertise. The AASM Board of Directors approved the final position statement.

POSITION STATEMENT

Use of a home sleep apnea test is not recommended for the diagnosis of obstructive sleep apnea in children. The ultimate judgment regarding propriety of any specific care must be made by the clinician, in light of the individual circumstances presented by the patient, available diagnostic tools, accessible treatment options, and resources.

Measurements of the stabilities of isolated retinal chromophores

The barrier energies for isomerization and fragmentation were measured for a series of retinal chromophore derivatives using a tandem ion mobility spectrometry approach. These measurements allow us to quantify the effect of charge delocalization on the rigidity of chromophores. We find that the role of the methyl group on the C13 position is pivotal regarding the ground state dynamics of the chromophore. Additionally, a correlation between quasi-equilibrium isomer distribution and fragmentation pathways is observed.

Anesthetic Dilemmas for Dynamic Evaluation of the Pediatric Upper Airway

Sleep cine magnetic resonance imaging and drug-induced sleep endoscopy are currently used to examine the patterns of dynamic airway collapse in children with obstructive sleep apnea. Providing anesthesia that mimics physiologic sleep in these children is a challenge but is critical for accurate interpretation of the airway evaluation. Anesthetic agents might negatively affect the upper airway evaluation. The anesthetic technique in these patients must be tailored to improve patient safety and obtain optimal study. This review focuses on the periprocedural challenges and anesthetic management of children presenting for dynamic evaluation of the upper airway.

Linear Dichroism Spectroscopy of Retinal with Picosecond Time Resolution

For the first time linear dichroism spectroscopy has been extended to the picosecond time regime. 11-cis retinal, all-trans retinal and 1,8-diphenyl-1,3,5,7-octatetraene (DPOT) are incorporated into polyethylene films and oriented by stretching the films. By measuring picosecond transient absorption spectra polarized parallel and perpendicular to the stretching direction and calculating the dichroic ratio we get informations about the molecular geometry in excited singlet and triplet states. The results may have relevance to vision.

Refinement of the Region for Split Hand/Foot Malformation 5 on 2q31.1

Background: Deletions that encompass 2q31.1 have been proposed as a microdeletion syndrome with common clinical features, including intellectual disability/developmental delay, microcephaly, cleft palate, growth delay, and hand/foot anomalies. In addition, several genes within this region have been proposed as candidates for split hand-foot malformation 5 (SHFM5). Methods: To delineate the genotype-phenotype correlation between deletions of this region, we identified 14 individuals with deletions at 2q31.1 detected by microarray analysis for physical and developmental disabilities. Results: All subjects for whom detailed clinical records were available had neurological deficits of varying degree. Seven subjects with deletions encompassing the HOXD cluster had hand/foot anomalies of varying severity, including syndactyly, brachydactyly, and ectrodactyly. Of 7 subjects with deletions proximal to the HOXD cluster, 5 of which encompassed DLX1/DLX2, none had clinically significant hand/foot anomalies. In contrast to previous reports, the individuals in our study did not display a characteristic gestalt of dysmorphic facial features. Conclusion: The absence of hand/foot anomalies in any of the individuals with deletions of DLX1/DLX2 but not the HOXD cluster supports the hypothesis that haploinsufficiency of the HOXD cluster, rather than DLX1/DLX2, accounts for the skeletal abnormalities in subjects with 2q31.1 microdeletions.

Case series: 2q33.1 microdeletion syndrome--further delineation of the phenotype

Recurrent deletions of 2q32q33 have recently been reported as a new microdeletion syndrome, clinical features of which include significant learning difficulties, growth retardation, dysmorphic features, thin and sparse hair, feeding difficulties, and cleft or high palate. Haploinsufficiency of one gene within the deleted region, SATB2, has been suggested to be responsible for most of the features of the syndrome. This article describes seven previously unreported patients with deletions at 2q33.1, all partially overlapping the previously described critical region for the 2q33.1 microdeletion syndrome. The deletions ranged in size from 35 kb to 10.4 Mb, with the smallest deletion entirely within the SATB2 gene. Patients demonstrated significant developmental delay and challenging behaviour, a particular behavioural phenotype that seems to be emerging with more reported patients with this condition. One patient in this cohort has a deletion entirely within SATB2 and has a cleft palate, whereas several patients with larger deletions have a high arched palate. In addition, one other patient has significant orthopaedic problems with ligamentous laxity. Interestingly, this patient has a deletion that lies just distal to SATB2. The orthopaedic problems have not been reported previously and are possibly an additional feature of this syndrome. Overall, this report provides further evidence that the SATB2 gene is the critical gene in this microdeletion syndrome. In addition, because the individuals in this study range in age from 3-19 years, these patients will help define the natural progression of the phenotype in patients with this microdeletion.

Blood mononuclear cell gene expression signature of postpartum depression

In sorrow thou shalt bring forth children (Genesis 3:16) seems as relevant today, with one of seven mothers afflicted by a depressive episode, constituting the most common medical complication after delivery. Why mothers are variably affected by mood symptoms postpartum remains unclear, and the pathogenesis and early molecular indicators of this divergent outcome have not been described. We applied a case-control design comparing differential global gene expression profiles in blood mononuclear cells sampled shortly after delivery at the time of inception of postpartum depression (PD). Nine antidepressant naive mothers showing high depressive scores and developing a persisting major depressive episode with postpartum onset were compared with 10 mothers showing low depressive scores and no depressive symptoms on prospective follow-up. A distinctive gene expression signature was observed after delivery among mothers with an emergent PD, with a significant overabundance of transcripts showing a high-fold differential expression between groups, and correlating with depressive symptom severity among all mothers. Early expression signatures correctly classified the majority of PD patients and controls. Those developing persisting PD exhibit a relative downregulation of transcription after delivery, with differential immune activation, and decreased transcriptional engagement in cell proliferation, and DNA replication and repair processes. Our data provide initial evidence indicating that blood cells sampled shortly after delivery may harbor valuable prognostic information for identifying the onset of persisting PD. Some of the informative transcripts and pathways may be implicated in the differential vulnerability that underlies depression pathogenesis.

Clinical guideline for the evaluation, management and long-term care of obstructive sleep apnea in adults

BACKGROUND

Obstructive sleep apnea (OSA) is a common chronic disorder that often requires lifelong care. Available practice parameters provide evidence-based recommendations for addressing aspects of care.

OBJECTIVE

This guideline is designed to assist primary care providers as well as sleep medicine specialists, surgeons, and dentists who care for patients with OSA by providing a comprehensive strategy for the evaluation, management and long-term care of adult patients with OSA.

METHODS

The Adult OSA Task Force of the American Academy of Sleep Medicine (AASM) was assembled to produce a clinical guideline from a review of existing practice parameters and available literature. All existing evidence-based AASM practice parameters relevant to the evaluation and management of OSA in adults were incorporated into this guideline. For areas not covered by the practice parameters, the task force performed a literature review and made consensus recommendations using a modified nominal group technique.

RECOMMENDATIONS

Questions regarding OSA should be incorporated into routine health evaluations. Suspicion of OSA should trigger a comprehensive sleep evaluation. The diagnostic strategy includes a sleep-oriented history and physical examination, objective testing, and education of the patient. The presence or absence and severity of OSA must be determined before initiating treatment in order to identify those patients at risk of developing the complications of sleep apnea, guide selection of appropriate treatment, and to provide a baseline to establish the effectiveness of subsequent treatment. Once the diagnosis is established, the patient should be included in deciding an appropriate treatment strategy that may include positive airway pressure devices, oral appliances, behavioral treatments, surgery, and/or adjunctive treatments. OSA should be approached as a chronic disease requiring long-term, multidisciplinary management. For each treatment option, appropriate outcome measures and long-term follow-up are described.

Circadian characteristics of serum calcium, magnesium and eight trace elements and of their metallo-moieties in urine of healthy middle-aged men

OBJECTIVE

To monitor the around-the-clock distribution of serum and urine concentrations of calcium, magnesium and eight trace elements and of those same elements in urine after their dialysis, and to statistically describe their circadian characteristics by chronobiological procedures.

MATERIALS AND METHODS

Serum and urine samples were collected every 3h over a single 24h period from eleven clinically-healthy male subjects, 41-60 years of age, and were analyzed for calcium (Ca), magnesium (Mg), iron (Fe), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), cobalt (Co), chromium (Cr), and nickel (Ni). Urines were also sequentially dialyzed against ammonium-barbituric acid buffer at pH 7.35+/-0.02 using a 12.000-14.000 molecular weight exclusion sieve and then reanalyzed for the same elements. Urine concentrations were adjusted by urine volume to reflect a 3h excretion rate. Time-series were analyzed for circadian time-effect by ANOVA and for rhythm characteristics by the single cosinor fitting procedure.

RESULTS

The dialysis effectively removed 90% of total solids, 97% of urea, 92% creatinine, 72% uric acid, and essentially all of glucose. It also removed 99% of potassium (K), 96% of sodium (Na), 65% of Ca and P, 55% of Mg, 41% of Zn and 88% of Ni. A significant or borderline-significant 24h rhythm in serum was detected for Ca, Mg, Fe, Cu, Zn, Cd and Cr; in untreated urine for Ca, Fe, Cu, Zn, Ni, creatinine and volume; and in dialyzed urine for Ca, Fe, Cu, Zn, Pb, Cr, Cd and Ni. A 12h component was significant or borderline-significant in serum for Mg, Fe, Zn, and Cd; in untreated urine for volume, creatinine, Ca, Mg, Cu, and Ni; and in dialyzed urine for Ca, Mg, Fe, Cu, Zn, and Cr. In general, values in serum were lowest near the onset of sleep and highest in the first half of the day (between 02:28 and 13:56 h), while highest values in untreated or dialyzed urine were found several hours later in the day and at night.

CONCLUSIONS

Significant circadian variations were found in levels of nearly every element that was measured in blood and urine of 11 healthy men, but with highest and lowest levels occurring at different times. This suggests not only that urine concentrations need to be adjusted for collection time interval and urine volume, but that different biological limits at different times of the 24h day should be applied for serum and urinary monitoring of trace elements. We also found that the non-dialyzable segments of these elements in urine represent metallo-moieties composed of proteinacious matter greater than 12,000-14,000 Daltons. Further studies would be of interest to reveal time specificity for metabolic functions associated with any of these trace elements.

Uric acid and renal function in multiple sclerosis

OBJECTIVE

The purpose of this study was to examine the circadian distribution of creatinine and uric acid clearances in subjects with Multiple Sclerosis.

MATERIALS AND METHODS

Eleven subjects with MS, 6 women (48+/-7y) and 5 men (58+/-5y) volunteered for this circadian study. Thirteen healthy females (39+/-11y) served as controls. Data of seven healthy male controls (64+/-8 y) were extracted from a similar circadian study conducted previously. Each MS patient, and each male control had blood samples drawn around the clock, at 3h intervals (8/24h), and each collected urines over 3h periods (8/24h). Each female control contributed only one blood sample and one complete 24h urine collection. Blood and urine samples were analyzed for a number of relevant analytes: ELAM, IL-6, NO, insulin, ACTH, aldosterone, cortisol, electrolytes, lymphocytes, monocytes including creatinine and uric acid clearances. Those were standardized to an average body surface area of 1.73 m2.

RESULTS

The relevant analytes demonstrated increased synthesis of insulin, IL-6, ELAM, monocytes, and reduced concentrations of serum NO. The creatinine clearances were significantly lower in MS females than in female controls, 63+/-22 vs.108+/-18 ml/min. They were also lower than those of MS males and male controls, 107.8+/-17, 97.5+/-8.2 ml/min. Uric acid clearances in MS females were also lower 6.9+/-2.4 vs. 10.5+/-4.4 ml/min. The uric acid clearance in MS males was higher than in male controls, 7.0+/-4.5 vs. 4.0+/-1.0 ml/min.

CONCLUSIONS

The alterations in selected relevant analytes and the reduced creatinine and uric acid clearances in females but not in males, suggest a renal dysfunction in MS females. These observations may contribute to understanding better the mechanism of renal dysfunction in female patients and perhaps this may be an additional factor contributing to greater frequency of MS in females than in male subjects.

Horizontal gaze palsy with progressive scoliosis can result from compound heterozygous mutations in ROBO3

BACKGROUND

Horizontal gaze palsy with progressive scoliosis (HGPPS) is an autosomal recessive disorder characterised by congenital absence of horizontal gaze, progressive scoliosis, and failure of the corticospinal and somatosensory axon tracts to decussate in the medulla. We previously reported that HGPPS patients from consanguineous pedigrees harbour homozygous mutations in the axon guidance molecule ROBO3.

METHODS

We now report two sporadic HGPPS children of non-consanguineous parents who harbour compound heterozygous mutations in ROBO3. The mother of one of the children also had scoliosis DNA was extracted from a blood sample from each participant using a standard protocol, and the coding exons of ROBO3 were amplified and sequenced as previously described.

RESULTS

Each patient harboured two unique heterozygous mutations in ROBO3, having inherited one mutation from each parent.

CONCLUSIONS

HGPPS can result from compound heterozygous mutations. More comprehensive examinations of parents and siblings of HGPPS patients are required to determine if the incidence of scoliosis in individuals harbouring heterozygous ROBO3 mutations is greater than in the general population.

Insights into excited-state and isomerization dynamics of bacteriorhodopsin from ultrafast transient UV absorption

A visible-pump/UV-probe transient absorption is used to characterize the ultrafast dynamics of bacteriorhodopsin with 80-fs time resolution. We identify three spectral components in the 265- to 310-nm region, related to the all-trans retinal, tryptophan (Trp)-86 and the isomerized photoproduct, allowing us to map the dynamics from reactants to products, along with the response of Trp amino acids. The signal of the photoproduct appears with a time delay of approximately 250 fs and is characterized by a steep rise ( approximately 150 fs), followed by additional rise and decay components, with time scales characteristic of the J intermediate. The delayed onset and the steep rise point to an impulsive formation of a transition state on the way to isomerization. We argue that this impulsive formation results from a splitting of a wave packet of torsional modes on the potential surface at the branching between the all-trans and the cis forms. Parallel to these dynamics, the signal caused by Trp response rises in approximately 200 fs, because of the translocation of charge along the conjugate chain, and possible mechanisms are presented, which trigger isomerization.

Peripheral blood mononuclear cell gene expression profiles identify emergent post-traumatic stress disorder among trauma survivors

Trauma survivors show marked differences in the severity and persistence of post-traumatic stress disorder (PTSD) symptoms. Early symptoms subside in most, but persist as acute and chronic PTSD in a significant minority. The underlying molecular mechanisms or outcome predictors determining these differences are not known. Molecular markers for identifying any mental disorder are currently lacking. Gene expression profiling during the triggering and development of PTSD may be informative of its onset and course. We used oligonucleotide microarrays to measure peripheral blood mononuclear cell (PBMC) gene expression of trauma survivors at the emergency room and 4 months later. Gene expression signatures at both time points distinguished survivors who met DSM-IV diagnostic criteria for PTSD at 1 and 4 months, from those who met no PTSD criterion. Expression signatures at both time points correlated with the severity of each of the three PTSD symptom clusters assessed 4 months following exposure among all survivors. Results demonstrate a general reduction in PBMCs' expression of transcription activators among psychologically affected trauma survivors. Several differentiating genes were previously described as having a role in stress response. These findings provide initial evidence that peripheral gene expression signatures following trauma identify an evolving neuropsychiatric disorder and are informative of its key clinical features and outcome. Replications in larger samples, as well as studies focusing on specific markers within the signatures discovered, are warranted to confirm and extend the diagnostic utility and pathogenetic implications of our results.

CIS: compound importance sampling method for protein-DNA binding site p-value estimation

MOTIVATION

A key aspect of transcriptional regulation is the binding of transcription factors to sequence-specific binding sites that allow them to modulate the expression of nearby genes. Given models of such binding sites, one can scan regulatory regions for putative binding sites and construct a genome-wide regulatory network. In such genome-wide scans, it is crucial to control the amount of false positive predictions. Recently, several works demonstrated the benefits of modeling dependencies between positions within the binding site. Yet, computing the statistical significance of putative binding sites in this scenario remains a challenge.

RESULTS

We present a general, accurate and efficient method for computing p-values of putative binding sites that is applicable to a large class of probabilistic binding site and background models. We demonstrate the accuracy of the method on synthetic and real-life data.

AVAILABILITY

The procedure for scanning DNA sequences and computing the statistical significance of putative binding site scores is available upon request at http://compbio.cs.huji.ac.il/CIS/ CONTACT: nir@cs.huji.ac.il.

Inferring quantitative models of regulatory networks from expression data

MOTIVATION

Genetic networks regulate key processes in living cells. Various methods have been suggested to reconstruct network architecture from gene expression data. However, most approaches are based on qualitative models that provide only rough approximations of the underlying events, and lack the quantitative aspects that are critical for understanding the proper function of biomolecular systems.

RESULTS

We present fine-grained dynamical models of gene transcription and develop methods for reconstructing them from gene expression data within the framework of a generative probabilistic model. Unlike previous works, we employ quantitative transcription rates, and simultaneously estimate both the kinetic parameters that govern these rates, and the activity levels of unobserved regulators that control them. We apply our approach to expression datasets from yeast and show that we can learn the unknown regulator activity profiles, as well as the binding affinity parameters. We also introduce a novel structure learning algorithm, and demonstrate its power to accurately reconstruct the regulatory network from those datasets.

Increasing asthma awareness among physicians: impact on patient management and satisfaction

Our objective was to investigate the impact of increased asthma awareness among primary care physicians on the asthma control and satisfaction of their patients. Physicians attended an asthma education session with emphasis on patient-physician partnership followed by 4 month monitored follow-up of patients aged 5-44 years with mild to moderate asthma. Findings were compared with a group of patients whose physician attended the session but did not participate in the follow-up and two other control groups. The study included pediatricians and general practitioners of Maccabi Healthcare Services and their patients. Asthma symptoms were rated by patients and physicians. Data on drug prescription and use were derived from the Maccabi central database. Patient response and satisfaction and physician satisfaction were evaluated by telephone interviews. Mean asthma symptom score improved from 2.0 to 1.1 in the study group of patients (p < 0.001). The use of reliever drugs decreased concomitantly with a rise in controller drugs in all patients. An improvement in asthma status was reported by 64% of the study patients and 39% of non-participating patients (p = 0.007). Fifty-eight percent of the patients rated their competence to deal with asthma as high before the intervention compared to 62% of the participating and 55% of the non-participating patients after the intervention (p = 0.002). Most physicians claimed that simply increasing their awareness on asthma led to beneficial results in their patients. Physician education followed by monitored follow-up enhanced asthma control and patient satisfaction. Nevertheless, physician education alone appears to have a significant isolated impact on asthma control.

Bullous myringitis: a case-control study

Prior studies have shown that bullous myringitis (BM) accounts for <10% of acute otitis media (AOM) cases, and that the distribution of viral and bacterial pathogens in BM is similar to that in AOM without BM, except for a relative increase in the proportion of Streptococcus pneumoniae in BM. We studied 518 cases of AOM in children aged 6 months to 12 years. Using tele-otoscopy to assist the diagnosis, we identified 41 cases (7.9%) with BM. Children who had AOM with BM were older than AOM patients without BM (median age: 4.3 years vs 18 months). We compared 41 cases of AOM with BM to 41 control cases of age-, race-, and gender-matched AOM patients without BM. When compared with this matched control group, children with BM had more severe symptoms at the time of diagnosis and were more likely to have bulging of the tympanic membrane in the quadrants that were not obscured by the bulla. Children with AOM and BM may require aggressive pain management. Although parents and clinicians may agree that a watchful waiting approach is appropriate for older children with mild AOM, children experiencing painful AOM with BM may not be successful candidates for a watchful-waiting approach, because parents may resist postponement of antibiotic therapy in children who are more symptomatic.

Evidence-based medicine: the key to guidelines, disease and care management programmes

INTRODUCTION

Evidence-based medicine (EBM) is based on the concept of applying best practice to the diagnosis or treatment of a single patient or clinical question, one patient at one time. Although this is useful as a practitioner seeing patients one at a time, it is limited in its application to populations or to single patients with multiple diseases. I will review how to apply EBM to the structure and implementation of population-based care management programmes.

METHODS

A review of the existing literature on the topic was undertaken in preparation for the First National Disease Management Conference-"Achieving seamless quality care across the continuum"-held between May 25 and 26, 2001. This material has been combined with experience and evidence of the author.

RESULTS

EBM and practice form the basis of the development of evidence-based guidelines that help lay the path for populations of patients with specific conditions. Care and disease management are the programmes that have been developed to implement evidence-based guidelines and best practice and to produce optimal outcomes in populations with chronic conditions, either single or multiple. Examples are presented to further the understanding of the reader.

CONCLUSIONS

To optimally improve the health of a population, chronic collaborative care programmes must be built and implemented that utilise best practice as defined by evidence in the literature.

Clinical, genetic and histopathologic findings in two siblings with muscle-eye-brain disease

PURPOSE

We present the clinical, genetic and histopathologic findings in two siblings with Muscle-Eye-Brain Disease (MEB-D), an autosomal recessive disease characterized by mental retardation, muscular dystrophy, retinal hypoplasia and brain abnormalities.

METHODS

Clinical, histopathologic and gene mapping studies of a family with two normal and two children with MEB-D.

RESULTS

Two siblings presented in the first few months of life with developmental delay, hypotonia, and strabismus. MRI of the brain showed colpocephaly, pontine and cerebellar atrophy, and diffuse white matter disease. Both patients were blind and had high myopia, strabismus, and retinal and optic nerve abnormalities. The older boy had glaucoma. Both children died from uncontrolled seizures. There was retinal, choroidal and RPE atrophy and optic nerve hypoplasia on ocular histopathology. Both patients shared the same parental haplotypes at the MEB locus on chromosome 1p, while an unaffected sibling did not, indicating possible linkage to the MEB locus.

CONCLUSIONS

Patients with MEB-D have severe visual impairment from retinal and optic nerve hypoplasia. High myopia appears to be a consistent finding. The ocular manifestations of MEB-D appear to be distinct from those of patients with Walker-Warburg syndrome.

Rich probabilistic models for gene expression

Clustering is commonly used for analyzing gene expression data. Despite their successes, clustering methods suffer from a number of limitations. First, these methods reveal similarities that exist over all of the measurements, while obscuring relationships that exist over only a subset of the data. Second, clustering methods cannot readily incorporate additional types of information, such as clinical data or known attributes of genes. To circumvent these shortcomings, we propose the use of a single coherent probabilistic model, that encompasses much of the rich structure in the genomic expression data, while incorporating additional information such as experiment type, putative binding sites, or functional information. We show how this model can be learned from the data, allowing us to discover patterns in the data and dependencies between the gene expression patterns and additional attributes. The learned model reveals context-specific relationships, that exist only over a subset of the experiments in the dataset. We demonstrate the power of our approach on synthetic data and on two real-world gene expression data sets for yeast. For example, we demonstrate a novel functionality that falls naturally out of our framework: predicting the "cluster" of the array resulting from a gene mutation based only on the gene's expression pattern in the context of other mutations.

Inferring subnetworks from perturbed expression profiles

Genome-wide expression profiles of genetic mutants provide a wide variety of measurements of cellular responses to perturbations. Typical analysis of such data identifies genes affected by perturbation and uses clustering to group genes of similar function. In this paper we discover a finer structure of interactions between genes, such as causality, mediation, activation, and inhibition by using a Bayesian network framework. We extend this framework to correctly handle perturbations, and to identify significant subnetworks of interacting genes. We apply this method to expression data of S. cerevisiae mutants and uncover a variety of structured metabolic, signaling and regulatory pathways.