Literature search from ms 29/4/2010

Literature search – from MS – 29/4/2010

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(1977). "Specialty conference: Reye's syndrome complicated by Ondine's curse." WESTERN JOURNAL OF MEDICINE 126(2): 110-8.

(2004). "Erratum: Anterior Spinal Artery Syndrome Complicated by the Ondine Curse (Archives of Neuroloy (December 2003) 60 (1787-1790))." ARCHIVES OF NEUROLOGY 61(3): 350.

Abbott, S. B. G., R. L. Stornetta, et al. (2009). "Photostimulation of retrotrapezoid nucleus Phox2b-expressing neurons in vivo produces long-lasting activation of breathing in rats." JOURNAL OF NEUROSCIENCE 29(18): 5806-5819.

The retrotrapezoid "nucleus" (RTN), located in the rostral ventrolateral medullary reticular formation, contains a bilateral cluster of [similar to]1000 glutamatergic noncatecholaminergic Phox2b-expressing propriobulbar neurons that are activated by CO2 in vivo and by acidification in vitro. These cells are thought to function as central respiratory chemoreceptors, but this theory still lacks a crucial piece of evidence, namely that stimulating these particular neurons selectively in vivo increases breathing. The present study performed in anesthetized rats seeks to test whether this expectation is correct. We injected into the left RTN a lentivirus that expresses the light-activated cationic channel ChR2 (channelrhodopsin-2) (H134R mutation; fused to the fluorescent protein mCherry) under the control of the Phox2-responsive promoter PRSx8. Transgene expression was restricted to 423 +/- 38 Phox2b-expressing neurons per rat consisting of noncatecholaminergic and C1 adrenergic neurons (3:2 ratio). Photostimulation delivered to the RTN region in vivo via a fiberoptic activated the CO2-sensitive neurons vigorously, produced a long-lasting (t1/2 = 11 s) increase in phrenic nerve activity, and caused a small and short-lasting cardiovascular stimulation. Selective lesions of the C1 cells eliminated the cardiovascular response but left the respiratory stimulation intact. In rats with C1 cell lesions, the mCherry-labeled axon terminals originating from the transfected noncatecholaminergic neurons were present exclusively in the lower brainstem regions that contain the respiratory pattern generator. These results provide strong evidence that the Phox2b-expressing noncatecholaminergic neurons of the RTN region function as central respiratory chemoreceptors. Copyright copyright 2009 Society for Neuroscience.

Abbott, S. B. G., R. L. Stornetta, et al. (2009). "Photostimulation of channelrhodopsin-2 expressing ventrolateral medullary neurons increases sympathetic nerve activity and blood pressure in rats." JOURNAL OF PHYSIOLOGY 587(23): 5613-5631.

To explore the specific contribution of the C1 neurons to blood pressure (BP) control, we used an optogenetic approach to activate these cells in vivo. A lentivirus that expresses channelrhodopsin-2 (ChR2) under the control of the catecholaminergic neuron-preferring promoter PRSx8 was introduced into the rostral ventrolateral medulla (RVLM). After 2-3 weeks, ChR2 was largely confined to Phox2b-expressing neurons (89%). The ChR2-expressing neurons were non-GABAergic, non-glycinergic and predominantly catecholaminergic ([similar to]54%). Photostimulation of ChR2-transfected RVLM neurons (473 nm, 20 Hz, 10 ms, [similar to]9 mW) increased BP (15 mmHg) and sympathetic nerve discharge (SND; 64%). Light pulses at 0.2-0.5 Hz evoked a large sympathetic nerve response (16 x baseline) followed by a silent period (1-2 s) during which another stimulus evoked a reduced response. Photostimulation activated most (75%) RVLM baroinhibited neurons sampled with 1/1 action potential entrainment to the light pulses and without accommodation during 20 Hz trains. RVLM neurons unaffected by either CO2 or BP were light-insensitive. Botzinger respiratory neurons were activated but their action potentials were not synchronized to the light pulses. Juxtacellular labelling of recorded neurons revealed that, of these three cell types, only the cardiovascular neurons expressed the transgene. In conclusion, ChR2 expression had no discernable effect on the putative vasomotor neurons at rest and was high enough to allow precise temporal control of their action potentials with light pulses. Photostimulation of RVLM neurons caused a sizable sympathoactivation and rise in blood pressure. These results provide the most direct evidence yet that the C1 neurons have a sympathoexcitatory function. copyright 2009 The Authors. Journal compilation copyright 2009 The Physiological Society.

Aboushanab, O. A., S. A. Alotaibi, et al. (2007). "Late onset central hypoventilation syndrome with hypothalamic dysfunction in a Kuwaiti girl." Kuwait Medical Journal 39(4): 376-378.

Late onset central hypoventilation syndrome (LO-CHS) is now considered a well-established disease that develops in previously normal children after infancy and has been regarded as a distinct entity from the congenital central hypoventilation syndrome (CCHS). Both conditions are associated with neural crest tumours, but hypothalamic dysfunction (HD) is a feature of LO-CHS and not CCHS. We report a case of LO-CHS with HD (LO-CHS/HD) who presented in respiratory failure at the age of five years.

Acosta, S., C. Lavarino, et al. (2009). "Comprehensive characterization of neuroblastoma cell line subtypes reveals bilineage potential similar to neural crest stem cells." BMC Developmental Biology 9: 12.

BACKGROUND: Neuroblastic tumors (NBT) derive from neural crest stem cells (NCSC). Histologically, NBT are composed by neuroblasts and Schwannian cells. In culture, neuroblastic (N-), substrate-adherent (S-) and intermediate phenotype (I-) cell subtypes arise spontaneously. METHODS: Here, neuroblastoma (NB) cell line subtypes were characterized according to embryonic peripheral nervous system development markers (GAP43, Phox2b, Sox10, c-kit, GD2, NF68, vimentin, S100beta, calcyclin and ABCG2), morphological features, gene expression and differentiation potential. I-type cells were investigated as a bipotential (neuronal and glial) differentiation stage. RESULTS: Positive immunostaining of NCSC (GAP43, c-kit, NF68, vimentin and Phox2b) and undifferentiated cell (ABCG2) markers was observed in all NB subtypes. N- and I-type cells displayed cytoplasmic membrane GD2 staining, while nuclear calcyclin was restricted to S-type. N- and I-type cells showed similar phenotype and immunoreactivity pattern. Differential gene expression was associated with each cell subtype. N- and I-type cells displayed similar differentiation capacity towards neuronal and glial lineage fates. S-type cells, upon induction, did not show a neuronal-like phenotype, despite gene expression changes. CONCLUSION: Results suggest that N- and I-type NB cell subtypes represent an immature bilineage stage, able to progress towards neuronal and glial fates upon induction of differentiation. S-type cells appear irreversibly committed to a glial lineage fate.

Adachi, M., D. Browne, et al. (2000). "Paired-like homeodomain proteins Phox2a/Arix and Phox2b/NBPhox have similar genetic organization and independently regulate dopamine beta-hydroxylase gene transcription." DNA & Cell Biology 19(9): 539-54.

The homeodomain transcription factors Arix/Phox2a and NBPhox/Phox2b play a role in the specification of the noradrenergic phenotype of central and peripheral neurons. To better understand the functions of these two factors, we have compared the genetic organization, chromosomal location, and transcriptional regulatory properties of Arix and NBPhox. The gene structure is very similar, with each gene containing three exons and two introns, extending a total of approximately 5 kb. Arix and NBPhox are unlinked in human and mouse genomes. NBPhox is located on human Chromosome 4p12 and mouse Chromosome 5, while Arix is located on human Chromosome 11q13 and mouse Chromosome 7. Both proteins bind to three sites in the promoter proximal region of the rat dopamine beta-hydroxylase gene (DBH). In vitro, Arix and NBPhox form DNA-independent multimers and exhibit cooperative binding to the DB1 regulatory element, which contains two homeodomain recognition sites. Both proteins regulate transcription from the rat DBH promoter, and transcription is synergistically increased in the presence of the protein kinase A catalytic subunit (PKA) plus either Arix or NBPhox. The transcription factors exhibit similar concentration-dependent efficacies, and when they are coexpressed, transcription is stimulated to a value approximately equal to that seen with either factor alone. The N-terminal segment of Arix is essential for transcriptional regulatory activity, and this region bears 50% identity with NBPhox, suggesting a similar mechanism of transcriptional activation of the DBH gene. We conclude from this study that Arix and NBPhox exhibit indistinguishable and independent transcriptional regulatory properties on the DBH promoter.

Afifi, T. O., B. J. Cox, et al. (2010). "The relation between types and frequency of gambling activities and problem gambling among women in Canada." Canadian Journal of Psychiatry - Revue Canadienne de Psychiatrie 55(1): 21-8.

OBJECTIVE: Canada experienced large-scale growth of the gambling industry during the 1990s. Clinical data have indicated that substantial proportions of people seeking help for gambling problems in Canada are women. A population health model was used to understand the relation between types and frequency of gambling activities and problem gambling among women in Canada. METHOD: Data used for the analysis were from the nationally representative Canadian Community Health Survey: Mental Health and Well-Being (CCHS 1.2; n = 10,056, women aged 15 years and older; data collected in 2002). RESULTS: The types of gambling associated with the highest odds of problem gambling among women in Canada were video lottery terminals (VLTs) outside the casino (OR 2.37 to 53.73; P < 0.01), VLTs inside the casino (OR 2.84 to 36.19; P < 0.001), and other casino games (OR 4.01 to 24.15; P < 0.001). CONCLUSIONS: These observations further our understanding of problem gambling among women in Canada and confirm that problem gambling among women is an important public health concern. Frequent VLT gambling, both outside and inside casinos, and other casino games are associated with the largest odds of problem gambling, which highlights an area of gambling in Canada that needs to be reassessed if problem gambling is to be prevented or reduced. Evidence-based research is necessary to inform healthy public policies on gambling in Canada. Findings from the current research have important research and policy implications.

Afifi, T. O., M. W. Enns, et al. (2005). "Investigating health correlates of adolescent depression in Canada." Canadian Journal of Public Health Revue Canadienne de Sante Publique. 96(6): 427-31.

BACKGROUND: The prevalence of depression rises sharply during adolescence. Understanding health correlates of adolescent depression may provide descriptive information with regard to which adolescents are more likely to be depressed. Health determinants have been found to have associations with depression in adult populations, but have never been investigated concurrently with depression in a national sample of adolescents in Canada. Therefore, the aim of the present investigation was to understand which health determinants would be significantly associated with adolescent depression. METHODS: A sample of 17,557 adolescents was used from the Canadian Community Health Survey (CCHS) 1.1 to determine the health correlates of adolescent depression among males and females. To understand the relationship between health determinants, logistic regressions were conducted. RESULTS: The survey had an 84.7% response rate. The past 12-month prevalence of depression among the sample of adolescents was 6.5% +/- 0.4% (3.4% +/- 0.27% for males and 9.8% +/- 0.44% for females). Reporting fair/poor perceived health, smoking, alcohol dependence, food allergies, migraine headaches, chronic bronchitis, and having physical health conditions had positive associations with depression for males and females. However, gender differences in the relationship between health correlates and depression were found. Even after controlling for all variables, females were still more likely to be depressed. CONCLUSIONS: Several health determinants were associated with depression in adolescents in Canada. However, the relationship between some health determinants and depression functioned differently for males and females.

Agrawal, A., J. Timothy, et al. (2008). "Bradycardia in neurosurgery." Clinical Neurology & Neurosurgery 110(4): 321-7.

Cushing reflex' is characterized by the occurrence of hypertension, bradycardia and apnoea secondary to raised increased intracranial pressure (ICP), leading to pressure on and or stretch, or both, of the brainstem. With the wide availability of monitoring facilities and advancements in investigation techniques, observation of increased intracranial pressure resulting in haemodynamic instability and bradycardia has been increasingly recognized in relation to many neurosurgical conditions and procedures. The causes of bradycardia include space occupying lesion involving or compressing the brain parenchyma (subdural haematoma, tumours, hydrocephalus), neurosurgical procedures (neuroendoscopy, placement of extradural drains), epileptic and non-epileptic seizures, trigemino-cardiac reflex, cerebellar lesions, spinal lesions (neurogenic shock, autonomic dysreflexia) and many other rare causes (Ventricular catheter obstruction in cases of hydrocephalus, colloid cysts related acute neurogenic cardiac dysfunction, Ondine's curse syndrome, etc.). This highlights that bradycardia can be a warning sign in many neurosurgical conditions and Cushing's reflex is a protective and effective action of the brain for preserving an adequate cerebral perfusion pressure despite an increased intracranial pressure. Management of these patients include identification and treatment of the underlying cause of bradycardia, anti-cholinergics and if necessary cardiac pacing, nevertheless, other causes of haemodynamic changes (i.e. anesthetic drugs, tumor manipulation) should also be considered and managed accordingly. We believe that this knowledge and understanding will help to identify the patients' at risk and will also help in the management of neurosurgical patients with bradycardia. [References: 86]

Ahmad, M., M. Cressman, et al. (1980). "Central alveolar hypoventilation syndromes." ARCHIVES OF INTERNAL MEDICINE 140(1): 29-30.

Syndromes of alveolar hypoventilation of central origin may no longer be viewed as medical curiosities. The symptoms of these interrelated entities often overlap; many patients with sleep apnea are obese and some demonstrate CO₂ retention during the day. Certain Pickwickian patients do not respond to weight loss and except for their obesity would be identified as having 'Ondine's curse'. Patients with primary alveolar hypoventilation have a high incidence of sleep-induced apneas. Studies of ventilatory control in the families of patients with COPD and hypercapnia have indicated that respiratory center sensitivity may be an inherited trait. Strohl et al have identified a family where the father and two sons had obstructive sleep apnea. A third son died during sleep at the age of 30 years, and a fourth asymptomatic son had a child who died at 4 months of age with the sudden infant death syndrome. It appears, then, that several interrelated syndromes of central alveolar hypoventilation exist. The common denominator may be an inherent (and possibly genetic) defect in the central regulatory mechanisms of ventilation that are manifest clinically when complicating factors such as obesity, infection, and airway obstruction supervene.

Akhtar-Danesh, N. and J. Landeen (2007). "Relation between depression and sociodemographic factors." International Journal of Mental Health Systems 1(1): 4.

ABSTRACT: BACKGROUND: Depression is one of the most common mental disorders in Western countries and is related to increased morbidity and mortality from medical conditions and decreased quality of life. The sociodemographic factors of age, gender, marital status, education, immigrant status, and income have consistently been identified as important factors in explaining the variability in depression prevalence rates. This study evaluates the relationship between depression and these sociodemographic factors in the province of Ontario in Canada using the Canadian Community Health Survey, Cycle 1.2 (CCHS-1.2) dataset. METHODS: The CCHS-1.2 survey classified depression into lifetime depression and 12-month depression. The data were collected based on unequal sampling probabilities to ensure adequate representation of young persons (15 to 24) and seniors (65 and over). The sampling weights were used to estimate the prevalence of depression in each subgroup of the population. The multiple logistic regression technique was used to estimate the odds ratio of depression for each sociodemographic factor. RESULTS: The odds ratio of depression for men compared with women is about 0.60. The lowest and highest rates of depression are seen among people living with their married partners and divorced individuals, respectively. Prevalence of depression among people who live with common-law partners is similar to rates of depression among separated and divorced individuals. The lowest and highest rates of depression based on the level of education is seen among individuals with less than secondary school and those with "other post-secondary" education, respectively. Prevalence of 12-month and lifetime depression among individuals who were born in Canada is higher compared to Canadian residents who immigrated to Canada irrespective of gender. There is an inverse relation between income and the prevalence of depression (p < 0.0001). CONCLUSION: The patterns uncovered in this dataset are consistent with previously reported prevalence rates for Canada and other Western countries. The negative relation between age and depression after adjusting for some sociodemographic factors is consistent with some previous findings and contrasts with some older findings that the relation between age and depression is U-shaped. The rate of depression among individuals living common-law is similar to that of separated and divorced individuals, not married individuals, with whom they are most often grouped in other studies.

Alam, G., H. Cui, et al. (2009). "MYCN promotes the expansion of Phox2B-positive neuronal progenitors to drive neuroblastoma development." AMERICAN JOURNAL OF PATHOLOGY 175(2): 856-66.

Amplification of the oncogene MYCN is a tumorigenic event in the development of a subset of neuroblastomas that commonly consist of undifferentiated or poorly differentiated neuroblasts with unfavorable clinical outcome. The cellular origin of these neuroblasts is unknown. Additionally, the cellular functions and target cells of MYCN in neuroblastoma development remain undefined. Here we examine the cell types that drive neuroblastoma development in TH-MYCN transgenic mice, an animal model of the human disease. Neuroblastoma development in these mice begins with hyperplastic lesions in early postnatal sympathetic ganglia. We show that both hyperplasia and primary tumors are composed predominantly of highly proliferative Phox2B(+) neuronal progenitors. MYCN induces the expansion of these progenitors by both promoting their proliferation and preventing their differentiation. We further identify a minor population of undifferentiated nestin(+) cells in both hyperplastic lesions and primary tumors that may serve as precursors of Phox2B(+) neuronal progenitors. These findings establish the identity of neuroblasts that characterize the tumor phenotype and suggest a cellular pathway by which MYCN can promote neuroblastoma development.

Alfonso, I., R. Luzondo, et al. (2007). "[Sleep disorders in the newborn]." MEDICINA 67(6 Pt 1): 556-60.

Sleep disorders are classified in dyssomnias, parasomnias, sleep disorder associated with medical and psychiatric disorders and proposed sleep disorders. Only the parasomnias have been studied as such in the newborn period. The parasomnias that occur in this age group are infant sleep apnea, congenital central hypoventilation syndrome, sudden infant death syndrome, and benign neonatal sleep myoclonus. Infant sleep apnea includes three entities: (1) apnea of prematurity, (2), apparent life threatening episodes with apnea and (3) obstructive sleep apnea. Congenital central hypoventilation syndrome can be associated with other autonomic system illness, such as Hirschsprung disease (Haddad syndrome) and neuroblastoma. The implementation of the supine sleep position and smoking free homes has diminished the frequency of sudden infant death syndrome. Benign neonatal sleep myoclonus should be considered in all newborns with a normal exam between the episodes when they always occur during sleep. This entity may be mistaken for status epilepticus, because it is associated with increases in heart rate. Benzodiazepines prolongs the duration of the episodes. [References: 31]

Ali, A. and H. Flageole (2008). "Diaphragmatic pacing for the treatment of congenital central alveolar hypoventilation syndrome." JOURNAL OF PEDIATRIC SURGERY 43(5): 792-6.

PURPOSE: The congenital central alveolar hypoventilation syndrome (CCAHS), also known as Ondine curse, is characterized by the absence of adequate autonomic control of respiration. The purpose of our study is to review our 20-year experience with diaphragmatic pacing as a treatment modality for CCAHS. METHODS: After obtaining institutional review board approval, the medical records of all 6 patients who currently are in the diaphragmatic pacing program at the Montreal Children's Hospital, Montreal, QC, Canada were reviewed. In addition to demographic details, associated anomalies were noted. Data regarding age at surgery, technical approach, and short- and long-term complications, including equipment failure and replacement, were noted. We were interested in the long-term outcome for this group of patients, particularly their quality of life. RESULTS: Our group of patients is composed of 4 females and 2 males. Their age ranges between 4 and 23 years. They were operated on at an average age of 47.8 months. The surgical approach used was mainly bilateral axillary thoracotomy. Internal component failure is the most common complication. All patients are ventilator free during the day. They all are active and productive, either attending school or working full time. CONCLUSION: Diaphragmatic pacing is an effective treatment of Ondine disease. As equipment improved, there is much less need for replacement of components. Patients can lead a much more normal existence by being ventilator free at least during the day, enabling them to participate in normal daily activities.

Alvarez Fernandez, J. A., C. Gomez Pellico, et al. (1985). "[Ondine's syndrome: presentation of a case associated with paralysis of the right hemidiaphragm]." MEDICINA CLINICA 84(6): 233-6.

Alvord, E. C., Jr. and C. M. Shaw (1989). "Congenital difficulties with swallowing and breathing associated with maternal polyhydramnios: neurocristopathy or medullary infarction?" JOURNAL OF CHILD NEUROLOGY 4(4): 299-306.

Two babies with congenital difficulties in swallowing and breathing are presented and contrasted. Both were associated with maternal polyhydramnios, but one was due to medullary infarction and the other to a malformation ("neurocristopathy"). In the former case, isolated tenth and twelfth cranial nerve palsies provided the clue as to the correct etiology, whereas the latter baby had dyscoordination of swallowing and breathing with sleep apnea ("Ondine's curse"). It is somewhat ironic that the case without a difficult delivery had the infarct, probably prenatal in onset, whereas the one with a difficult delivery had the congenital malformation. Neural crest cells are known to migrate widely and to develop greatly different functions, but the fact that their central associations of neural tube origin may also be affected has not previously been emphasized in the etiopathogenesis of the congenital malformation. A variety of syndromes with combinations of many defects may be seen in which too many or too few cells are formed, with more or less serious consequences especially for the respiratory and gastrointestinal systems. [References: 50]