Multimodal intraoperative monitoring: towards a routine use in surgical treatment of severe spinal disorders

European Spine Journal -     

Association of psychiatric disorders and sleep apnea in a large cohort

STUDY OBJECTIVES: We conducted the present study to determine whether psychiatric disorders are commonly associated with sleep apnea in Veterans Health Administration beneficiaries. METHOD: The Veterans Health Administration maintains several centralized databases containing healthcare data for more than 4 million veterans. We reviewed data from 1998 to 2001 and identified patient records having International Classification of Diseases-Ninth Edition-Clinical Modification codes indicating sleep apnea and various psychiatric conditions. Subsequently, we compared age, sex, ethnicity, and prevalence of comorbid psychiatric conditions for Veterans Health Administration beneficiaries with and without sleep apnea. RESULTS: Out of 4,060,504 unique cases, 118,105 were identified as having sleep apnea (estimated prevalence of 2.91%). Mean age at the time of diagnosis was 57.6 years. Psychiatric comorbid diagnoses in the sleep apnea group included depression (21.8%), anxiety (16.7%), posttraumatic stress disorder (11.9%), psychosis (5.1), and bipolar disorders (3.3%). Compared with patients not diagnosed with sleep apnea, a significantly greater prevalence (P < .0001) was found for mood disorders, anxiety, posttraumatic stress disorder, psychosis, and dementia in patients with sleep apnea. CONCLUSIONS: Sleep apnea is associated with a higher prevalence of psychiatric comorbid conditions in Veterans Health Administration beneficiaries. This association suggests that patients with psychiatric disorders and coincident symptoms suggesting sleep-disordered breathing should be evaluated for sleep apnea.     

Erythropoietin regulates hypoxic ventilation in mice by interacting with brainstem and carotid bodies

Apart from its role in elevating red blood cell number, erythropoietin (Epo) exerts protective functions in brain, retina and heart upon ischaemic injury. However, the physiological non-erythroid functions of Epo remain unclear. Here we use a transgenic mouse line (Tg21) constitutively overexpressing human Epo in brain to investigate Epo's impact on ventilation upon hypoxic exposure. Tg21 mice showed improved ventilatory response to severe acute hypoxia and moreover improved ventilatory acclimatization to chronic hypoxic exposure. Furthermore, following bilateral transection of carotid sinus nerves that uncouples the brain from the carotid body, Tg21 mice adapted their ventilation to acute severe hypoxia while chemodenervated wild-type (WT) animals developed a life-threatening apnoea. These results imply that Epo in brain modulates ventilation. Additional analysis revealed that the Epo receptor (EpoR) is expressed in the main brainstem respiratory centres and suggested that Epo stimulates breathing control by alteration of catecholaminergic metabolism in brainstem. The modulation of hypoxic pattern of ventilation after i.v. injection of recombinant human Epo in WT mice and the dense EpoR immunosignal observed in carotid bodies showed that these chemoreceptors are sensitive to plasma levels of Epo. In summary, our results suggest that Epo controls ventilation at the central (brainstem) and peripheral (carotid body) levels. These novel findings are relevant to understanding better respiratory disorders including those occurring at high altitude.     

A NEW METHOD FOR DETECTING EYE MOVEMENT IN SLEEP

A new method of detecting eye movements (EMs) during sleep is described. The method consists of an electromechanical measurement using micro-miniaturized silver cup electrodes. These electrodes, when placed on the eyelid, produce electro-oculographic (EOG) recordings similar to the usual electrical method. The eyelid method offers the advantage of a relatively “clean” recording showing only EMs and movement artifact, with no intermingling of EEG and EOG. Furthermore, the method is at least one and one half times as sensitive as the usual EOG technique. In addition to these two special advantages, it also offers the features of conventional methods, convenience of DC coupling, independence from signal converters, ease of analyzing EM directionality, and durability despite the small size of the electrodes. Fabrication of the electrodes, recording configurations, and simultaneous comparisons to both the usual EOG technique and to a strain gauge method are described.     

Regional distribution of antibodies to herpes simplex virus type 1 (HSV-1) and HSV-2 in men and women in Ontario,Canada

This study estimated the regional and age- and gender-specific seroprevalences of herpes simplex virus type 1 (HSV-1) and HSV-2 in Ontario, Canada. Stored serum specimens from subjects aged 15 to 44 years, including men (n = 979), women not under prenatal care (n = 638), and women under prenatal care (n = 701) submitted for routine viral serology were randomly selected according to regional population size from public health laboratories. HSV-1 and HSV-2 testing was done with the MRL enzyme immunoassay (EIA) (Focus Technologies), and HSV-2 was also tested by the Gull/Meridian EIA. Specimens discordant for HSV-2 antibodies between the two EIAs were resolved by a recombinant immunoblot assay (Focus Technologies). The overall age- and gender-standardized seroprevalences of HSV-1 and HSV-2 were 51.1% (95% confidence interval [CI], 50.1 to 52.1) and 9.1% (95% CI, 8.6 to 9.7), respectively. The seroprevalence of HSV-1 antibodies increased from 26.9 to 54.7% in men between 15 to 16 and 40 to 44 years of age, from 32.0 to 88.7% in women not under prenatal care, and from 55.2 to 69.2% in women under prenatal care. The seroprevalence of HSV-2 increased from 3.8 to 21.3% in men between 15 to 16 and 40 to 44 years of age, from 0 to 18.9% in women not under prenatal care, and from 3.4 to 23.1% in women under prenatal care. HSV-2 results were discordant for 3.3% (76 of 2,318) of specimens. Both types of HSV antibodies appeared to be acquired earlier among women under prenatal care than among men and women not under prenatal care. Antibodies were more prevalent among people in northern Ontario (72.9% of subjects [range, 68.4 to 77.4%] for HSV-1 and 13.7% of subjects [95% CI, 10.2 to 17.2%] for HSV-2) than elsewhere.     

Signal transduction in human B cells initiated via Ig{beta} ligation

Ig and Igß heterodimers are non-covalently associatedwith Ig to compose the antigen receptor complexes on B cells.The demonstration that different sets of tyrosine kinases bindto the cytoplasmic tails of Ig and Igß suggests thatIg and Igß may activate distinct second messengerpathways. In this study, we examined the effects of mAbs againstan exposed epitope of human Igß on pre-B and B celltriggering. Cross-linkage of Igß on B cells leadsto activation of tyrosine kinases, hydrolysis of phosphatidylinositides,and elevation of intracellular Ca²⁺, effects qualitatively identicalto those of anti-_µ mAbs. Our observations thus indicatethat cross-linking of Igß does not segregate signaltransduction pathways connected with the cytoplasmic talls ofIg and Igß. Ig ligation has been reported to be moreeffective in triggering pre-B than B cells, whereas our resultsindicated that Igß ligation is more efficient in triggeringB than pre-B cells. In addition to their activation properties,the anti-Igß mAbs effectively modulated B cell receptorcomplexes and blocked terminal differentiation of all plasmacell isotypes. The findings support the idea that anti-Igßcould serve as a universal B cell immunosuppressant.