Primary ciliary dyskinesia (PCD, MIM 242650) is characterized by recurrent infections of the respiratory tract due to reduced mucociliary clearance and by sperm immobility. Half of the affected offspring have situs inversus (reversed organs), which results from randomization of left-right (LR) asymmetry. We previously localized to chromosome 5p a PCD locus containing DNAH5, which encodes a protein highly similar to the Chlamydomonas gamma-dynein heavy chain. Here we characterize the full-length 14-kb transcript of DNAH5. Sequence analysis in individuals with PCD with randomization of LR asymmetry identified mutations resulting in non-functional DNAH5 proteins.
This study tested the effectiveness of the AutoSet self-titrating nasal continuous positive airway pressure (nCPAP) system in treating obstructive sleep apnea (OSA), and choosing a suitable pressure for subsequent conventional fixed-pressure nCPAP therapy. Twenty-one adult men with untreated OSA were studied with full polysomnography on each of four nights: diagnostic, manual and AutoSet nCPAP titration (in random order), and conventional fixed-pressure nCPAP at the pressure recommended by the AutoSet titration. Titration was satisfactorily performed in 20 of 21 subjects. Severe mask leak prevented automated titration in one subject and caused transient unnecessary increases in pressure in three subjects. In the 20 subjects, respiratory disturbance index (RDI) was 60.3 +/- 5.7 events/h (mean +/- SEM) on the diagnostic night. RDI was lower with manual titration (10.1 +/- 3.0, p < 0.001), and lower still with Autoset (2.8 +/- 0.9, p < 0.01) and fixed pressure (2.5 +/- 0.7, p = ns versus AutoSet) nCPAP. There were similar changes in the arousal index, which was 52.7 +/- 4.6 events/h on the diagnostic night, 14.2 +/- 2.4 with manual titration and 8.9 +/- 0.9 with AutoSet titration, and 9.5 +/- 1.0 on the night of conventional fixed-pressure CPAP (p < 0.001 versus diagnostic). We conclude that the AutoSet system is suitable for automated nCPAP pressure titration.
The plasma level of fibrinogen is felt to be an independent risk factor for vascular events. Obstructive sleep apnea (OSA) has a high prevalence in patients with stroke and may also be an independent risk factor. The aim of our study was to determine the association between OSA and plasma levels of fibrinogen in patients with stroke. Polysomnography was performed during neurological rehabilitation in 113 patients (82 men, 31 women, age 58 +/- 11.1 yr, mean +/- SD) with ischemic stroke. OSA was absent (RDI < 5) in 44 patients, 42 had mild OSA (5 < or = RDI < 20), and 27 had moderate to severe OSA (RDI > or = 20). Parameters of OSA (respiratory disturbance index [RDI], oxygen indices) were correlated to plasma levels of fibrinogen, measured in the morning after admission to rehabilitation. Fibrinogen was positively correlated with RDI (r = 0.24, p = 0.007), duration of the longest apnea (r = 0.18, p = 0.049), and negatively correlated with several oxygen indices including average minimal oxygen saturation (r = -0.41, p < 0.001). Correlation coefficients were slightly higher when excluding patients with stroke of presumed cardiac origin. Multiple linear regression identified minimal mean oxygen saturation and sex as independent predictors of fibrinogen level. The correlation between severity of coexisting OSA and fibrinogen level in patients with stroke suggests a possible pathophysiological mechanism for an increased risk of stroke in patients with OSA.
Sleep-disordered breathing (SDB) in the form of obstructive sleep apnea is a possible risk factor for stroke. We carried out a cross-sectional survey out in a rehabilitation center among patients with first-ever stroke to further determine the incidence and types of SDB and its relationship to known risk factors for stroke. Full polysomnography was performed in 147 consecutive patients (95 men, 52 women, age 61+/-10 years) admitted to our neurological Rehabilitation Department 46+/-20 days after first-ever stroke. Subjective sleepiness (Epworth Sleepiness Scale), vascular risk factors, anthropometric data, and polysomnographic findings were compared between stroke patients with varying degrees of SDB. With a cutoff point for the respiratory disturbance index (RDI) of 5, 10, 15, or 20 the respective prevalence of SDB was 61%, 44%, 32%, and 22%. The type of SDB was generally obstructive, with dominant central apneas in only 6% of patients. Patients with an RDI of 20 or higher had less REM sleep, thicker necks, and a more central type of obesity. Even in patients with an RDI of 20 or higher subjective sleepiness, although higher than in those without SDB, was not a predominant symptom. Snoring and anthropometric data suggest that obstructive SDB may have existed prior to stroke. The prevalence of hypertension and coronary heart disease were higher among stroke patients with an RDI of 20 or higher than in those without SDB. We conclude that the prevalence of SDB among patients with stroke is high. Examination of stroke should include screening for SDB.
Mouth leak is common during nasal ventilatory assistance, but its effects on ventilatory support and on sleep architecture are unknown. The acute effect of sealing the mouth on sleep architecture and transcutaneous carbon dioxide tension (Ptc,CO 2 ) was tested in 9 patients (7 hypercapnic) on longterm nasal bilevel ventilation with symptomatic mouth leak.Patients slept with nasal bilevel ventilation at their usual settings on two nights in random order. On one night, the mouth was taped closed. Nocturnal nasal bilevel ventilatory support has become an important and successful therapy for respiratory failure during sleep [1±3]. At present, nasal masks are more common than mouthpieces, mouth-nose masks or full face masks (perhaps because of issues related to comfort, fit and deadspace) but a major practical problem is escape of air via the mouth, as has been well documented for nasal continuous positive airway pressure (CPAP) [4,5].In the only study to date to directly measure the effect of mouth leaks on effectiveness of ventilatory support, CAR-REY et al.[6] investigated the effect of voluntary mouth opening on diaphragm electromyogram (EMG) activity during awake nasal intermittent positive pressure ventilation in 5 subjects. With the mouth closed, diaphragm EMG dropped to 15% of unassisted control, but with the mouth open, returned to 98% of unassisted control, implying complete loss of ventilatory support.Mouth leak is ubiquitous during noninvasive ventilatory support in sleep. BACH et al. [7] demonstrated that during nasal intermittent positive pressure ventilation (NIPPV), severe leak (>33% of tidal volume escaping) was present for a median of 55% of sleep time, and was associated with 7.5 desaturations (of at least 4%) per hour of sleep.MEYER et al. [8] found severe mouth leak during most of sleep time and 100% of slow wave sleep.Mouth leak could lead to severe sleep fragmentation, either directly via airway irritation, or indirectly via a reduction in effectiveness of ventilation as discussed above. In the study by BACH et al. [7], there were a total of 34 arousals . h -1 and 74% of desaturations were terminated by either an arousal or a lightening of sleep stage. The authors concluded that leak was reducing ventilatory effectiveness and causing desaturation, and that arousal reversed the leak and desaturation. Similarly, in the study of MEYER et al. [8] there were 46 arousals . h -1 in stages I-II nonrapid eye movement (NREM) sleep, associated in time with mouth leak. However, association in time does not establish causality, and it is not known whether preventing the mouth leak would improve sleep quality.The purpose of the present paper was to directly assess the effect of mouth leak on sleep architecture and transcutaneous carbon dioxide tension (Ptc,CO 2 ) during nasal bilevel ventilatory support, by preventing the leak. To do this, the authors measured the first-night effect of taping the mouth closed, on sleep architecture and Ptc,CO 2 in patients already on long-term nasal bilevel venti...
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