Sleep Position Detection for Closed-Loop Treatment of Sleep-Related Breathing Disorders.

Reliable detection of sleep positions is essential for the development of technical aids for patients with position-dependent sleep-related breathing disorders. We compare personalized and generalizable sleeping position classifiers using unobtrusive eight-channel pressure-sensing mats. Data of six male patients with confirmed position-dependent sleep apnea was recorded during three subsequent nights. Personalized position classifiers trained using leave-one-night-out cross-validation on average reached an F1-score of 61.3% for supine/non-supine and an F1-score of 46.2% for supine/lateral-left/lateral-right classification. The generalizable classifiers reached average F1-scores of 62.1% and 49.1% for supine/non-supine and supine/lateral-left/lateral-right classification, respectively. In-bed presence ("bed occupancy") could be detected with an average F1-score of 98.1%. This work shows that personalized sleep-position classifiers trained with data from two nights have comparable performance to classifiers trained with large interpatient datasets. Simple eight-channel sensor mattresses can be used to accurately detect in-bed presence required for closed-loop systems but their use to classify sleep-positions is limited.

Hunting for B + → K + τ + τ - imprints on the B + → K + µ + µ - dimuon spectrum.

We investigate the possibility of indirectly constraining the B + → K + τ + τ - decay rate using precise data on the B + → K + µ + µ - dimuon spectrum. To this end, we estimate the distortion of the spectrum induced by the B + → K + τ + τ - → K + µ + µ - re-scattering process, and propose a method to simultaneously constrain this (non-standard) contribution and the long-distance effects associated to hadronic intermediate states. The latter are constrained using the analytic properties of the amplitude combined with data and perturbative calculations. Finally, we estimate the sensitivity expected at the LHCb experiment with present and future datasets. We find that constraints on the branching fraction of O ( 10 - 3 ) , competitive with current direct bounds, can be achieved with the current dataset, while bounds of O ( 10 - 4 ) could be obtained with the LHCb upgrade-II luminosity.

Mitochondrial diseases represent a risk factor for valproate-induced fulminant liver failure.

We report on 3 siblings (2 females and 1 male) with chronic progressive external ophthalmoplegia (CPEO), compatible with inherited mitochondrial cytopathy. The younger of the two sisters died at the age of 37 due to progressive respiratory failure. The older one presented with a status epilepticus at the age of 39 and was treated with valproate. Five months after the start of treatment, she developed fulminant liver failure and died. The brother has suffered from CPEO since early childhood but has had so far no other symptoms of a mitochondrial disease. A muscle biopsy from the younger sister revealed ragged-red fibers and decreased activities of complex I and IV of the respiratory chain but no pathogenic mutations in the mitochondrial tRNA genes or in several locations in the coding region of the mitochondrial genome. In the older sister's liver (obtained post-mortem), mitochondrial DNA was fragmented and could not be investigated. The clinical presentation and the biochemical findings suggest that all 3 siblings suffered from a mitochondrial cytopathy. Since mitochondrial cytopathies and valproate-induced fulminant liver failure are both rare events, an association between them is likely. Mitochondrial diseases should therefore be considered as a risk factor for valproate-induced liver failure and be excluded before treatment with valproate.

Microvesicular steatosis, hemosiderosis and rapid development of liver cirrhosis in a patient with Pearson's syndrome.

BACKGROUND/AIMS: Pearson's marrow-pancreas syndrome consists of refractory sideroblastic anemia with vacuolization of marrow precursors and exocrine pancreas dysfunction. Patients with this disease usually have large deletions of the mitochondrial genome. We report a patient with Pearson's syndrome who had predominantly hepatic manifestations such as microvesicular steatosis, hemosiderosis and rapidly developing cirrhosis. METHODS: Analysis of the mitochondrial and nuclear genomes, determination of enzyme activities and of the hepatic iron content were performed using standard techniques of molecular biology and biochemistry. RESULTS: The patient had typical ringed sideroblasts in a bone marrow smear and a 7436-bp deletion of the mitochondrial genome in all tissues investigated, compatible with Pearson's syndrome. He died within 3 months after birth due to liver failure. Histopathological analysis of the liver revealed complete cirrhosis with signs of chronic cholestasis, microvesicular steatosis and massive hemosiderosis. In addition, the patient was heterozygous for the C282Y and H63D mutations of the hemochromatosis gene. CONCLUSIONS: Pearson's syndrome should be added to the list of neonatal diseases which can cause microvesicular steatosis, hepatic accumulation of iron and liver cirrhosis.

The effect of ketamine anesthetic induction on muscle responses to transcranial magnetic cortex stimulation studied in man.

In man, an anesthetic agent that induces surgical anesthesia with minimal influence on descending pyramidal tract activity remains to be found. Anesthesia with ketamine allows recording of stable compound muscle action potentials (CMAPs) to single transcranial magnetic stimulations of the motor cortex (CortStim) in monkeys. This report describes the findings in 5 patients, where CMAPs to CortStim were recorded from the right hypothenar during anesthesia induction with ketamine. The agent was injected intravenously every 90 s in 6 steps of 0.5 mg up to a maximum of 3 mg/kg body weight (BW). Surgical anesthesia was achieved after ketamine injection of 1.5 (n = 4 patients) or 2.0 mg/kg BW (n = 1). In the five individuals tested, CMAP amplitudes and latencies (mean; range) were 2.6 (1.6-5.8) mV and 22.8 (20.4-24.6) ms before induction, and 1.6 (0.3-4.7) mV and 23.5 (21.7-24.5) ms after administration of the maximum dose. The paired differences (mean +/- 1 S.D.) were 0.8 +/- 0.6 mV and 1.0 +/- 0.8 ms and were statistically not significant (n = 5, P = 0.1, Wilcoxon-test). With ketamine as a single anesthetic induction agent CMAPs to single CortStim remain easily recordable even in dosages higher than those necessary to induce surgical anesthesia. All other previously tested anesthetic agents suppress CMAPs to CortStim as soon as the patient is unconscious.

Influence of some anesthetic agents on muscle responses to transcranial magnetic cortex stimulation: a pilot study in humans.

The effects of some commonly used intravenous and inhalational anesthetic agents on the motor evoked responses to transcranial magnetic cortex stimulation were assessed in 17 subjects. Compound motor action potentials (CMAPs) of the abductor digiti minimi muscle were recorded. Baseline values (12 stimulations/subject) were established before anesthesia was induced with a single agent administered in steps up to a maximal dose (MaxDose). Cortical stimulation was performed and depth of anesthesia was assessed according to Guedel after each dose. A common feature was the marked intra- and interindividual variability of baseline values of CMAPs in those patients not premedicated, those premedicated, and the anesthetized patients. The average amplitude of CMAPs was related to the depth of anesthesia in a given subject, whereas onset latencies of CMAPs did not systematically change. CMAPs were markedly reduced or abolished after administration of potent sedative drugs such as midazolam (MaxDose, 0.4 mg/kg body weight), pentothal (MaxDose, 8 mg/kg), propofol (MaxDose, 2 mg/kg), and isoflurane (MaxDose, 1.9 and 3.7 vol %), as soon as patients reached Stage II and Stage III anesthesia. When fentanyl (MaxDose, 8 micrograms/kg) or nitrous oxide (MaxDose, 79%) was used, the subjects reached Stages I and II, but not Stage III. With these drugs, reliable recording of CMAPs was possible even with the maximal administered dose.

Severe neonatal asphyxia due to X-linked centronuclear myopathy.

Severe neonatal centronuclear myopathy is inherited as an X-linked condition characterized by primary asphyxia, extreme muscular hypotonia and absent spontaneous movements. We report seven cases from three families to point out the importance of diagnosis with regard to prognosis, outcome and genetic counselling. In hypotonic diseases, analysis of cerebrospinal fluid, electromyography, nerve conduction velocity creatine kinase and a skin biopsy for fibroblast cultures for metabolic investigations are usually carried out. Needle muscle biopsy is an additional valuable investigation to establish diagnosis. In all our patients we found an increased number of centrally located nuclei with perinuclear halos confirming the diagnosis of centronuclear myopathy. The diagnosis of this disorder will become of greater importance as soon as carrier detection and prenatal diagnosis by DNA-technology are routinely available.

[Results in microsurgical carotid artery endarterectomy]. / Ergebnisse der mikrochirurgischen Karotisendarteriektomie.

100 consecutive carotid endarterectomies were performed by a microscopic technique with monitoring of cerebral perfusion by transcranial Doppler sonography and EEG. No additional cerebral deficits occurred in this series. Perioperative mortality due to medical complications occurred in 2 instances. During the average follow-up period of 15 months, 1 patient suffered a lethal cerebral infarction ipsilateral to the operated carotid artery and 1 patient a contralateral minor stroke. 2 patients died from unrelated causes during follow-up.

Results of microsurgical carotid endarterectomy. A prospective study with transcranial Doppler and EEG monitoring, and elective shunting.

100 consecutive carotid endarterectomies in a total of 93 patients were performed using the operative microscope. Cerebral perfusion and activity were monitored with simultaneous transcranial Doppler (TCD) and EEG. Thiopentone for cerebral protection was given prior to carotid clamping in 11 cases when an insufficient collateral circulation was suspected on the basis of the pre-operative TCD or angiography and if temporary intraluminal shunting was to be avoided because of a high bifurcation, long stenosis or associated carotid artery kinking. A temporary intraluminal shunt was inserted electively if the mean middle cerebral artery flow velocity fell after cross-clamping below 30-40%. Direct closure of the arteriotomy was preferred over a patch graft, which was performed only in cases with concomitant stricture of the arterial wall. No peri-operative strokes occurred in the present series. Two patients died due to medical complications in the post-operative period. During the mean follow-up of 15 months, 1 patient suffered a lethal stroke ipsilateral to the treated carotid artery and another patient had a minor contralateral stroke. Two patients died of unrelated causes during follow-up. Two patients suffered a single reversible neurologic deficit corresponding to the treated carotid territory. Four other patients had a single contralateral hemispheric or retinal reversible ischaemic attack during follow-up.