Respiratory Cycle-Related EEG Changes during Sleep Reflect Esophageal Pressures

Study Objectives:

Respiratory cycle-related EEG changes (RCREC) have been demonstrated during sleep by digital analysis and hypothesized to represent subtle inspiratory microarousals that may help to explain daytime sleepiness in patients with sleep-disordered breathing. We therefore examined for the first time associations between RCREC and esophageal pressure swings (ΔPes) that reflect work of breathing.

Design:

Retrospective analysis

Setting:

Academic sleep laboratory

Patients:

Forty adults referred for suspected sleep disordered breathing

Interventions:

Polysomnography with esophageal pressure monitoring and automatic computation of ΔPes using a novel algorithm.

Results:

Computed ΔPes for nearly all respiratory cycles during sleep correlated well with visual scoring of selected respiratory cycle samples (Spearman rho = 0.86, P < 0.0001). The RCREC within the sigma EEG range (12.5–15.5 Hz) rather than that within other frequency ranges most often showed significant within-subject inverse correlations with ΔPes. In contrast, in between-subject comparisons, beta (15.5–30.5 Hz) and to a lesser extent theta (4.5–7.5 Hz) RCREC, rather than sigma RCREC, showed significant inverse associations with mean ΔPes.

Conclusions:

Variation within subjects of sigma RCREC with ΔPes supports previous evidence that RCREC within this range may reflect microarousals exacerbated by increased work of breathing. Correlation of beta and theta, but not sigma RCREC with ΔPes in between-subject comparisons is more difficult to explain but suggests that ranges other than sigma also deserve further investigation for clinical utility.

Citation:

Chervin RD; Malhotra RK; Burns JW. Respiratory cycle-related EEG changes during sleep reflect esophageal pressures. SLEEP 2008;31(12):1713–1720.     

Impact of vitamin A supplementation through different dosages of red palm oil and retinol palmitate on preschool children

Red palm oil (5 ml and 10 ml), ground nut oil fortified with 400 and 800 retinol equivalent retinol palmitate, and ground nut oil (5 and 10 ml), were administered to six groups of preschool children (four experimental and two control groups) in randomly assigned balwadis of Ramanathapuram District of Tamil Nadu for a period of 7 months, to monitor the difference in the efficacy of the mode of supplementation and the optimum dose for improving vitamin A status. Results show that red palm oil groups recorded more gain in retinol and beta-carotene levels compared to other dosage groups, and that administration of 10 ml did not offer any substantial improvement over the 5-ml daily dose.     

Primary cardiac lymphoma masquerading as right atrial myxoma causing complete heart block—a case report

Secondary involvement of the heart and pericardium by systemic lymphoma is well documented. Primary Cardiac lymphomas (PCL) are extremely rare. Incidence of PCL is increasing in immunocompromised patients. However PCL in immunocompetent is much rarer. We report such a case of PCL in an immunocompetent elderly female masquerading as right atrial myxoma causing complete heart block which was surgically debulked successfully. Her rhythm resumed to Sinus rhythm following surgical debulking. Immunohistochemistry of the excised tumour revealed Diffuse Large B cell lymphoma. With combination chemotherapy, she is symptom free on six months follow up.     

Loss of LFA-1, but not Mac-1, protects MRL/MpJ-Fas(lpr) mice from autoimmune disease

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by immune complex-mediated tissue injury. Many different adhesion molecules are thought to participate in the development of SLE; however, few studies have directly examined the contributions of these proteins. Here we demonstrate that LFA-1 plays an essential role in the development of lupus in MRL/MpJ-Fas(lpr) mice. Mice deficient in LFA-1, but not Mac-1, showed significantly increased survival, decreased anti-DNA autoantibody formation, and reduced glomerulonephritis. The phenotype of the LFA-1-deficient mice was similar to that observed in beta(2) integrin-deficient (CD18-null) MRL/MpJ-Fas(lpr) mice, suggesting a lack of redundancy among the beta(2) integrin family members and other adhesion molecules. These studies identify LFA-1 as a key contributor in the pathogenesis of autoimmune disease in this model, and further suggest that therapeutic strategies targeting this adhesion molecule may be beneficial for the treatment of SLE.     

Enhanced expression of stem cell antigen-1 (Ly-6A/E) in lymphocytes from lupus prone mice correlates with disease severity

B6.Sle1 mice, congenic for the NZM2410-derived lupus susceptibility locus, Sle1 on chromosome 1 exhibit many of the features seen in human lupus including activated lymphocytes and high titers of antinuclear autoantibodies. Among the different surface molecules that were aberrantly expressed on the B6.Sle1 lymphocytes was Ly-6A/E. Splenic B- and T-lymphocytes but not myeloid cells from B6.Sle1 mice exhibited enhanced levels of Ly-6A/E compared to B6 controls. In particular, MZ B cells, GC B cells and B-cell blasts expressed the highest levels of Ly-6A/E in both strains, with the levels being even higher on B6.Sle1 derived cells. Following stimulation with LPS or anti-IgM, there was a profound up-regulation in Ly-6A/E, particularly on MZ B cells and B-cell blasts. CD4 and CD8 T cells also up-regulated Ly-6A/E after stimulation with anti-CD3 and anti-CD28. These studies were extended to additional autoimmune strains including B6.Sle3, B6.Sle1.lpr and BXSB. Importantly, Ly-6A/E levels on lymphocytes were commensurate with the degree of disease exhibited by these lupus strains. Finally, it appears that increased interferon levels, in addition to antigen receptor stimulation, may also be a factor accounting for elevated Ly-6A/E in lupus. Given these observations it is important to elucidate the functional role of Ly-6A/E in lupus in future studies.     

Alkali-free bioactive glasses for bone tissue engineering: a preliminary investigation

An alkali-free series of bioactive glasses has been designed and developed in the glass system CaO-MgO-SiO₂-P₂O₅-CaF₂ along the diopside (CaMgSi₂O₆)-fluorapatite (Ca₅(PO₄)₃F)-tricalcium phosphate (3CaO·P₂O₅) join. The silicate network in all the investigated glasses is predominantly coordinated in Q² (Si) units, while phosphorus tends to remain in an orthophosphate (Q⁰) environment. The in vitro bioactivity analysis of glasses has been made by immersion of glass powders in simulated body fluid (SBF) while chemical degradation has been studied in Tris-HCl in accordance with ISO-10993-14. Some of the investigated glasses exhibit hydroxyapatite formation on their surface within 1-12 h of their immersion in SBF solution. The sintering and crystallization kinetics of glasses has been investigated by differential thermal analysis and hot-stage microscopy, respectively while the crystalline phase evolution in resultant glass-ceramics has been studied in the temperature range of 800-900 °C using powder X-ray diffraction and scanning electron microscopy. The alkaline phosphatase activity and osteogenic differentiation for glasses have been studied in vitro on sintered glass powder compacts using rat bone marrow mesenchymal stem cells. The as-designed glasses are ideal candidates for their potential applications in bone tissue engineering in the form of bioactive glasses as well as glass/glass-ceramic scaffolds.     

Participating in a virtual reality balance exercise program can reduce risk and fear of falls

Objective

The objective of this study was to quantify the effectiveness of virtual reality balance games (VRBG) to decrease risk and fear of falls among women.

Methods

Thirty six community dwelling women aged 56 and above were randomly divided into experimental (exercises using VRBG focus on improving balance) and control (conventional balance exercises) groups. Both groups attended a twice 6 weekly exercise session for an hour. Risk and fear of falls were measured with Physiological Profile Approach (PPA) and Activity Specific Balance Scale (ABC-6). Pre and post intervention differences between the groups were examined using two way repeated measures ANOVA.

Results

Both VRBG and conventional balance exercise groups had significant decrease in PPA (p < 0.001) and ABC-6 (p < 0.01) after the interventions. However, no significant effects were demonstrated between the groups in PPA (p = 0.18) and ABC-6 (p = 0.25) post intervention. Time and group interaction effect were not significant for PPA (p = 0.18) and ABC-6 (p = 0.45).

Conclusions

Practising VRBG can increase balance confidence and decrease risk of falls among community dwelling women.