Green synthesis of precise inorganic nanomaterials is a major challenge. Magnetotactic bacteria biomineralise magnetite nanoparticles (MNPs) within membrane vesicles (magnetosomes), which are embedded with dedicated proteins that control nanocrystal formation. Some such proteins are used in vitro to control MNP formation in green synthesis; however, these membrane proteins self-aggregate, making their production and use in vitro challenging and difficult to scale.
View Article and Find Full Text PDFBackground And Objective: Obstructive sleep apnoea (OSA) is a prevalent sleep disorder associated with increased cardiovascular morbidity and mortality. Whether treatment of OSA improves cardiovascular risk remains controversial. Our aim was to determine a consensus opinion of key sleep medicine stakeholder groups as to the cardiovascular benefits of treating moderate-severe OSA.
View Article and Find Full Text PDFBackground: The clinical utility of limited-channel sleep studies (which are increasingly conducted at home) versus laboratory polysomnography (PSG) for diagnosing obstructive sleep apnea (OSA) is unclear.
Objective: To compare patient outcomes after PSG versus limited-channel studies.
Design: Multicenter, randomized, noninferiority study.
Cheyne-Stokes respiration (CSR) foretells deleterious outcomes in patients with heart failure. Currently, the size of therapeutic intervention is not guided by the patient's underlying pathophysiology. In theory, the intervention needed to resolve CSR, as a control system instability (loop gain >1), can be predicted knowing the baseline loop gain and how much it falls with therapy.
View Article and Find Full Text PDFStudy Objectives: Depression is a risk factor for medication non-compliance. We aimed to identify if depression is associated with poorer adherence during home-based autotitrating continuous positive airway pressure (autoPAP) titration.
Design: Mixed retrospective-observational study.
Pulse oximetry provides a simple, non-invasive approximation of arterial oxygenation in a wide variety of clinical settings including emergency and critical-care medicine, hospital-based and ambulatory care, perioperative monitoring, inpatient and outpatient settings, and for specific diagnostic applications. Pulse oximetry is of utility in perinatal, paediatric, adult and geriatric populations but may require use of age-specific sensors in these groups. It plays a role in the monitoring and treatment of respiratory dysfunction by detecting hypoxaemia and is effective in guiding oxygen therapy in both adult and paediatric populations.
View Article and Find Full Text PDFBackground And Aims: Depression and obstructive sleep apnoea are two common entities, with common symptoms that make identification of either condition difficult. Our aim was to examine, within a group of patients referred with snoring and obstructive sleep apnoea, (i) the prevalence of depression with the 14-question Hospital Anxiety and Depression Scale (HADS), (ii) the correlation between the two lead depression symptoms from the Mini-International Neuropsychiatric Interview (MINI) and HADS, and (iii) the relationship between depression symptoms with physiological markers of OSA.
Methods: An observational study of depression questionnaires in patients referred because of snoring to a sleep clinic within university-affiliated public teaching hospital.
Objectives: The effect of body position and sleep state on sleep apnoea have major clinical implications in the management of patients, yet are infrequently reported in the scientific literature. The aim of this study was to compare and contrast the prevalence and severity of supine-only and rapid eye movement (REM)-only obstructive sleep apnoea (OSA) in a population.
Methods: Prospective cohort analysis of the influence of supine body position and REM sleep on the severity of apnoea in 100 consecutive patients with OSA (apnoea-hypopnoea index [AHI]>5) using attended polysomnography with continuous digital monitoring in an accredited sleep laboratory.
Rationale: Patients with heart failure (HF) and Cheyne-Stokes respiration or periodic breathing (PB) often demonstrate improved cardiac function when treatment with continuous positive airway pressure (CPAP) resolves PB. Unfortunately, CPAP is successful in only 50% of patients, and no known factor predicts responders to treatment. Because PB manifests from a hypersensitive ventilatory feedback loop (elevated loop gain [LG]), we hypothesized that PB persists on CPAP when LG far exceeds the critical threshold for stable ventilation (LG = 1).
View Article and Find Full Text PDFIntroduction: The influence of sleeping position on obstructive sleep apnea severity is well established. However, in central sleep apnea with Cheyne Stokes respiration (CSA-CSR) in which respiratory-control instability plays a major pathophysiologic role, the effect of position is less clear.
Study Objectives: To examine the influence of position on CSA-CSR severity as well as central and mixed apnea frequency.
While there has been strong evidence for the ability of neuropsychological performance at resolution of posttraumatic amnesia to predict later productivity, there has been less conclusive evidence for the relationship of neuropsychological test scores to concurrent productivity status. The purpose of the current study was to evaluate the relationship of neuropsychological test performance at 1 year post-injury to productivity assessed at the same time point. Participants were 518 persons with medically documented TBI who were enrolled in the TBI Model Systems Research and Demonstration Project.
View Article and Find Full Text PDFPrevious small-scale studies of the effect of sleep-disordered breathing (SDB) on prognosis in congestive heart failure (CHF) are either lacking or conflicting. The aim of this study was to assess the impact of the presence and type of SDB on mortality in a patient group with severe CHF referred to a specialised heart failure centre. Out of 78 patients ((mean +/- SD) 53 +/- 9 yrs, left ventricular ejection fraction 19.
View Article and Find Full Text PDFStudy Objective: Central sleep apnea (CSA) associated with Cheyne-Stokes respiration in patients with congestive heart failure (CHF) is thought to be an acquired pattern of respiratory control instability related, at least in part, to elevated sympathetic nervous system activity. The effect of restoring heart function to normal with heart transplantation in patients with CHF and CSA has only been reported within weeks of the transplant and with varying results. The purpose of the study was to evaluate the impact of successful heart transplant on sympathetic nervous system activity and CSA severity in patients with CHF.
View Article and Find Full Text PDFAlcohol Clin Exp Res
December 2002
Background: Prenatal alcohol exposure has long been associated with alterations in brain structure and behavioral changes. The corpus callosum can be affected by heavy prenatal alcohol exposure, and agenesis (absence) of this structure occurs more often in children with fetal alcohol syndrome than in the general population or in other developmentally delayed populations. Although the majority of children with fetal alcohol syndrome do not have agenesis of the corpus callosum, callosal area is reduced in this population, particularly in the anterior and posterior regions.
View Article and Find Full Text PDFHyperventilation is the key factor contributing to the development of idiopathic nonhypercapnic central sleep apnoea (ICSA), where left ventricular systolic function is normal. ICSA is reported to occur in 20% of patients with left ventricular diastolic dysfunction, in whom elevated pulmonary vascular pressures and resultant increased pulmonary vagal afferent traffic may contribute to hyperventilation. The contribution of the two potential mechanisms responsible for the hyperventilation seen in the following ICSA was measured: 1) left ventricular diastolic dysfunction-induced pulmonary hypertension; and 2) increased peripheral and central hypercapnic ventilatory responses (HCVR).
View Article and Find Full Text PDFBackground: Memory deficits are reported commonly in children with fetal alcohol syndrome. However, little is known about nonverbal memory performance in this population.
Methods: The current study examined learning and memory abilities in alcohol-exposed children and nonexposed controls.
Objective: To investigate the factor structure and concurrent validity of the Caregiver Appraisal Scale (CAS) in a sample of caregivers of adults with traumatic brain injury (TBI).
Design: Prospective cohort study.
Setting: Two sites: (1) Outpatient clinics associated with a comprehensive inpatient brain injury rehabilitation program and (2) a comprehensive residential postacute rehabilitation program in the Southern United States.
Objective: To investigate maintenance of gains after discharge from a postacute rehabilitation program.
Design: Longitudinal cohort study, with inclusion based on availability of subjects at three time points.
Setting: Comprehensive postacute rehabilitation program in the Southern United States.
Working memory has been described as the temporary "online" storage and the subsequent manipulation and retrieval of information. It has been suggested that the prefrontal cortex is a primary site of working memory. Schizophrenia patients, who are thought to have prefrontal cortical dysfunction, have demonstrated inconsistent deficits on a variety of verbal and spatial working memory tests.
View Article and Find Full Text PDFModerate-to-large quantities of alcohol are known to aggravate severe obstructive sleep apnoea (OSA), however, the reported effects of moderate alcohol consumption upon mild-to-moderate OSA are inconsistent. Given the reported benefits of moderate alcohol consumption on cardiovascular mortality, recommendations regarding the management of patients with OSA are difficult to formulate. The aim of this study was to evaluate the effects of moderate alcohol on sleep and breathing in subjects with mild-to-moderate OSA.
View Article and Find Full Text PDFAm J Respir Crit Care Med
December 2000
Given that the apnea-ventilation cycle length during central sleep apnea (CSA) with congestive heart failure (CHF) is approximately 70 s, we hypothesized that rapidly responsive peripheral CO(2) ventilatory responses would be raised in CHF-CSA and would correlate with the severity of CSA. Sleep studies and single breath and rebreathe hypercapnic ventilatory responses (HCVR) were measured as markers of peripheral and central CO(2) ventilatory responses, respectively, in 51 subjects: 12 CHF with no apnea (CHF-N), 8 CHF with obstructive sleep apnea (CHF-OSA), 12 CHF-CSA, 11 CSA without CHF ("idiopathic" CSA; ICSA), and 8 normal subjects. Single breath HCVR was equally elevated in CHF-CSA and ICSA groups compared with CHF-N, CHF-OSA, and normal groups (0.
View Article and Find Full Text PDFBackground: It is widely known that prenatal alcohol exposure is related to cognitive and behavioral deficits throughout childhood and adolescence. Much research has focused on understanding and quantifying the cognitive profile of children with fetal alcohol syndrome (FAS) with relatively less empirical research on behavioral or psychosocial adjustment. The primary purpose of this study was to examine the behavioral and psychosocial profile of children exposed to heavy amounts of alcohol prenatally.
View Article and Find Full Text PDFAlcohol Clin Exp Res
December 1998
Alcohol-exposed children display delayed motor development and impaired fine- and gross-motor skills, including deficits in the maintenance of balance. In a recent study, we assessed the contribution of visual, somatosensory, and vestibular information to the ability to maintain balance. Our findings suggested that alcohol-exposed children were overly reliant on somatosensory information and were unable to compensate by using the visual and/or vestibular systems.
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