Flinders University

About: Flinders University is a education organization based out in Adelaide, South Australia, Australia. It is known for research contribution in the topics: Population & Health care. The organization has 12033 authors who have published 32831 publications receiving 973172 citations. The organization is also known as: Flinders University of South Australia.

A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative?

Abstract: Study Objectives: The purposes of this study were to compare the benefits of different length naps relative to no nap and to analyze the electroencephalographic elements that may account for the benefits. Design: A repeated-measures design included 5 experimental conditions: a no-nap control and naps of precisely 5, 10, 20, and 30 minutes of sleep. Setting: Nocturnal sleep restricted to about 5 hours in participants’ homes was followed by afternoon naps at 3:00 PM and 3 hours of postnap testing conducted in a controlled laboratory environment. Participants: Twenty-four healthy, young adults who were good sleepers and not regular nappers. Measurements and Results: The 5-minute nap produced few benefits in comparison with the no-nap control. The 10-minute nap produced immediate improvements in all outcome measures (including sleep latency, subjective sleepiness, fatigue, vigor, and cognitive performance), with some of these benefits maintained for as long as 155 minutes. The 20minute nap was associated with improvements emerging 35 minutes after napping and lasting up to 125 minutes after napping. The 30-minute nap produced a period of impaired alertness and performance immediately after napping, indicative of sleep inertia, followed by improvements lasting up to 155 minutes after the nap. Conclusions: These findings suggest that the 10-minute nap was overall the most effective afternoon nap duration of the nap lengths examined in this study. The implications from these results also suggest a need to consider a process occurring in the first 10 minutes of sleep that may account for the benefits associated with brief naps.

Targeted drug delivery using genetically engineered diatom biosilica

Abstract: The ability to selectively kill cancerous cell populations while leaving healthy cells unaffected is a key goal in anticancer therapeutics. The use of nanoporous silica-based materials as drug-delivery vehicles has recently proven successful, yet production of these materials requires costly and toxic chemicals. Here we use diatom microalgae-derived nanoporous biosilica to deliver chemotherapeutic drugs to cancer cells. The diatom Thalassiosira pseudonana is genetically engineered to display an IgG-binding domain of protein G on the biosilica surface, enabling attachment of cell-targeting antibodies. Neuroblastoma and B-lymphoma cells are selectively targeted and killed by biosilica displaying specific antibodies sorbed with drug-loaded nanoparticles. Treatment with the same biosilica leads to tumour growth regression in a subcutaneous mouse xenograft model of neuroblastoma. These data indicate that genetically engineered biosilica frustules may be used as versatile 'backpacks' for the targeted delivery of poorly water-soluble anticancer drugs to tumour sites.

Associations of Obstructive Sleep Apnea With Atrial Fibrillation and Continuous Positive Airway Pressure Treatment: A Review

Abstract: Importance Obstructive sleep apnea (OSA) is the most common clinically significant breathing abnormality during sleep. It is highly prevalent among patients with atrial fibrillation (AF), and it promotes arrhythmogenesis and impairs treatment efficacy. Observations The prevalence of OSA ranges from 3% to 49% in population-based studies and from 21% to 74% in patients with AF. Diagnosis and treatment of OSA in patients with AF requires a close interdisciplinary collaboration between electrophysiologists, cardiologists, and sleep specialists. Because the prevalence of OSA is high in patients with AF and most do not report daytime sleepiness, sleep-study evaluation may be reasonable for patients being considered for rhythm control strategy. Acute, transient apnea-associated atrial electrophysiological changes and increased occurrence of AF triggers associated with short episodes of intermittent deoxygenation and reoxygenation, intrathoracic pressure changes during obstructed breathing efforts, and sympathovagal activation combine to create a stimulus for AF triggers and a complex and dynamic substrate for AF during sleep. Repeated episodes of long-term OSA are eventually associated with structural remodeling and changes in electrical conduction in the atrium. Observational data suggest OSA reduces the efficacy of catheter-based and pharmacological antiarrhythmic therapy. Nonrandomized studies have shown that treatment of OSA by continuous positive airway pressure can help to maintain a sinus rhythm after electrical cardioversion and catheter ablation in patients with AF. However, it remains unclear which sleep apnea metric should be used to determine severity and guide such treatment in patients with AF. Conclusions and Relevance Data from nonrandomized studies of patients with AF suggest that treatment of OSA by continuous positive airway pressure may help to maintain sinus rhythm after electrical cardioversion and improve catheter ablation success rates. Randomized clinical trials are needed to confirm the association between OSA and AF the benefits of treatment of OSA and the need for and cost-effectiveness of routine OSA screening and treatment.

Selectivity of substrate (trifluoperazine) and inhibitor (amitriptyline, androsterone, canrenoic acid, hecogenin, phenylbutazone, quinidine, quinine, and sulfinpyrazone) “probes” for human udp-glucuronosyltransferases

Abstract: Relatively few selective substrate and inhibitor probes have been identified for human UDP-glucuronosyltransferases (UGTs). This work investigated the selectivity of trifluoperazine (TFP), as a substrate, and amitriptyline, androsterone, canrenoic acid, hecogenin, phenylbutazone, quinidine, quinine, and sulfinpyrazone, as inhibitors, for human UGTs. Selectivity was assessed using UGTs 1A1, 1A3, 1A4, 1A6, 1A7, 1A8, 1A9, 1A10, 2B7, and 2B15 expressed in HEK293 cells. TFP was confirmed as a highly selective substrate for UGT1A4. However, TFP bound extensively to both HEK293 lysate and human liver microsomes in a concentration-dependent manner (fuinc 0.20-0.59). When corrected for nonspecific binding, Km values for TFP glucuronidation were similar for both UGT1A4 (4.1 microM) and human liver microsomes (6.1+/-1.2 microM) as the enzyme sources. Of the compounds screened as inhibitors, hecogenin, alone, was selective; significant inhibition was observed only for UGT1A4 (IC50 1.5 microM). Using phenylbutazone and quinine as "models," inhibition kinetics were variously described by competitive and noncompetitive mechanisms. Inhibition of UGT2B7 by quinidine was also investigated further, because the effects of this compound on morphine pharmacokinetics (a known UGT2B7 substrate) have been ascribed to inhibition of P-glycoprotein. Quinidine inhibited human liver microsomal and recombinant UGT2B7, with respective Ki values of 335+/-128 microM and 186 microM. In conclusion, TFP and hecogenin represent selective substrate and inhibitor probes for UGT1A4, although the extensive nonselective binding of the former should be taken into account in kinetic studies. Amitriptyline, androsterone, canrenoic acid, hecogenin, phenylbutazone, quinidine, quinine, and sulfinpyrazone are nonselective UGT inhibitors.

Efficacy of oral risperidone, haloperidol, or placebo for symptoms of delirium among patients in palliative care: a randomized clinical trial

Abstract: Importance Antipsychotics are widely used for distressing symptoms of delirium, but efficacy has not been established in placebo-controlled trials in palliative care. Objective To determine efficacy of risperidone or haloperidol relative to placebo in relieving target symptoms of delirium associated with distress among patients receiving palliative care. Design, Setting, and Participants A double-blind, parallel-arm, dose-titrated randomized clinical trial was conducted at 11 Australian inpatient hospice or hospital palliative care services between August 13, 2008, and April 2, 2014, among participants with life-limiting illness, delirium, and a delirium symptoms score (sum of Nursing Delirium Screening Scale behavioral, communication, and perceptual items) of 1 or more. Interventions Age-adjusted titrated doses of oral risperidone, haloperidol, or placebo solution were administered every 12 hours for 72 hours, based on symptoms of delirium. Patients also received supportive care, individualized treatment of delirium precipitants, and subcutaneous midazolam hydrochloride as required for severe distress or safety. Main Outcome and Measures Improvement in mean group difference of delirium symptom score (severity range, 0-6) between baseline and day 3. Five a priori secondary outcomes: delirium severity, midazolam use, extrapyramidal effects, sedation, and survival. Results Two hundred forty-seven participants (mean [SD] age, 74.9 [9.8] years; 85 women [34.4%]; 218 with cancer [88.3%]) were included in intention-to-treat analysis (82 receiving risperidone, 81 receiving haloperidol, and 84 receiving placebo). In the primary intention-to-treat analysis, participants in the risperidone arm had delirium symptom scores that were significantly higher than those among participants in the placebo arm (on average 0.48 Units higher; 95% CI, 0.09-0.86;P = .02) at study end. Similarly, for those in the haloperidol arm, delirium symptom scores were on average 0.24 Units higher (95% CI, 0.06-0.42;P = .009) than in the placebo arm. Compared with placebo, patients in both active arms had more extrapyramidal effects (risperidone, 0.73; 95% CI, 0.09-1.37;P = .03; and haloperidol, 0.79; 95% CI, 0.17-1.41;P = .01). Participants in the placebo group had better overall survival than those receiving haloperidol (hazard ratio, 1.73; 95% CI, 1.20-2.50;P = .003), but this was not significant for placebo vs risperidone (hazard ratio, 1.29; 95% CI, 0.91-1.84;P = .14). Conclusions and Relevance In patients receiving palliative care, individualized management of delirium precipitants and supportive strategies result in lower scores and shorter duration of target distressing delirium symptoms than when risperidone or haloperidol are added. Trial Registration anzctr.org.au Identifier:ACTRN12607000562471.