The effect of caffeine abstinence on sleep among habitual caffeine users with poor sleep

Caffeine is the most widely used psychoactive substance in the world and is known to disrupt healthy sleep. However, very few studies have directly tested the effect of caffeine abstinence on sleep, and these have yielded inconsistent findings. The purpose of the present study was to examine changes in sleep following caffeine abstinence and examine the extent to which characteristics of habitual caffeine use moderated this change. Participants included 66 healthy, young adults with habitual caffeine use and poor sleep. During the 2‐week baseline, sleep was assessed using wrist actigraphy and daily caffeine use was assessed with bedtime diaries. Eligible participants then completed 1 week of caffeine abstinence, during which sleep was measured with wrist actigraphy. Multilevel models found no significant differences between either mean levels or growth trajectories of total sleep time or sleep efficiency between baseline and caffeine abstinence. Mean levels of sleep onset latency also did not differ between baseline and caffeine abstinence. A small but significant quadratic effect was observed, such that sleep onset latency decreased during the first few days of caffeine abstinence, then increased to levels above baseline. Characteristics of caffeine use did not moderate changes in sleep between baseline and caffeine abstinence. These data suggest that abstaining from caffeine may not result in long‐term sleep improvement for habitual caffeine users, which contradicts the common sleep health recommendation. The present findings encourage more rigorous investigation of the effectiveness of caffeine restriction on sleep.     

Acute surgical unit safely reduces unnecessary after-hours cholecystectomy

Introduction

The acute surgical model has been trialled in several institutions with mixed results. The aim of this study was to determine whether the acute surgical model provides better outcomes for patients with acute biliary presentation, compared with the traditional emergency surgery model of care.

Methods

A retrospective review was carried out of patients who were admitted for management of acute biliary presentation, before and after the establishment of an acute surgical unit (ASU). Outcomes measured were time to operation, operating time, after-hours operation (6pm – 8am), length of stay and surgical complications.

Results

A total of 342 patients presented with acute biliary symptoms and were managed operatively. The median time to operation was significantly reduced in the ASU group (32.4 vs 25.4 hours, p=0.047), as were the proportion of operations performed after hours (19.5% vs 2.5%, p<0.001) and the median length of stay (4 vs 3 days, p<0.001). The median operating time, rate of conversion to open cholecystectomy and wound infection rates remained similar.

Conclusions

Implementation of an ASU can lead to objective differences in outcomes for patients who present with acute cholecystitis. In our study, the ASU significantly reduced time to operation, the number of operations performed after hours and length of stay.     

地高辛抗血清对老龄大鼠心肌缺氧复氧损伤影响的体外实验

目的:观察内洋地黄素水平在老龄大鼠心肌细胞缺氧复氧损伤中的变化以及地高辛抗血清的保护作用。方法:实验于2005-04/05在皖南医学院病理生理教研室完成。取10只24月龄和10只6月龄雄性普通级SD大鼠,分别制备青年和老龄大鼠心肌细胞匀浆,老龄和成年大鼠为两大组,每组分为7小组,即每只大鼠心肌随机分到各小组中,共计14小组,每组10支试管。正常对照组:给予CO2和O2的混合气体(1∶19)通气40min;缺氧复氧组:CO2,O2,N2混合气体(5∶4∶91)通气20min后换成CO2和O2的混合气体(1∶19)通气20min;阴性对照组:同缺氧复氧组,但于再给氧前加入0.1mL的非特异性灭活兔血清;地高辛抗血清组:同缺氧复氧组,但于再给氧前加入0.1mL的非特异性地高辛抗血清(分别为1∶90000,60000,30000,10000)。观察大鼠心肌细胞钠-钾-三磷酸腺苷酶活性和线粒体内钙聚集程度,分析其剂量-效应关系。结果:①缺氧复氧时,青年组和老龄组大鼠心肌分泌内洋地黄素均显著升高,但老龄组显著低于青年组[(0.081±0.03),(0.153±0.06);(0.074±0.04),(0.125±0.05)ng/g;P<0.05]。②缺氧复氧时,老龄组与青年组心肌细胞钠-钾-三磷酸腺苷酶活性显著受抑制[(0.239±0.015),(0.778±0.050);(0.350±0.047),(0.836±0.044)μkat/g;P<0.05],老龄组与青年组相比,其抑制效应显著增强(P<0.05)。③缺氧复氧时,老龄组线粒体内钙与青年组比较明显增强[(0.082±0.011),(0.495±0.095);(0.075±0.008),(0.412±0.084)mmol/L,P<0.05]。④老龄组和青年组相比,地高辛抗血清呈剂量依赖性的恢复钠-钾-三磷酸腺苷酶活性(r=0.695,0.797,n=5,P<0.05),减轻线粒体内钙聚集(r=-0.565,-0.649,n=5,P<0.05);经直线回归分析发现,老龄鼠回归系数大于青年组(酶活性抑制K=1.50,0.94,线粒体内钙K=-7.43,-6.46)。结论:心肌细胞缺氧复氧时,老龄鼠损伤较青年大鼠更显著,其机制与老龄大鼠心肌细胞钠-钾-三磷酸腺苷酶对内洋地黄素敏感性增加有关,地高辛抗血清对老龄大鼠心肌细胞缺氧复氧保护作用更有效。     

Art participation for psychosocial wellbeing during stroke rehabilitation: a feasibility randomised controlled trial

Purpose: To examine the feasibility of undertaking a pragmatic single-blind randomised controlled trial (RCT) of a visual arts participation programme to evaluate effects on survivor wellbeing within stroke rehabilitation.

Methods: Stroke survivors receiving in-patient rehabilitation were randomised to receive eight art participation sessions (n?=?41) or usual care (n?=?40). Recruitment, retention, preference for art participation and change in selected outcomes were evaluated at end of intervention outcome assessment and three-month follow-up.

Results: Of 315 potentially eligible participants 81 (29%) were recruited. 88% (n?=?71) completed outcome and 77% (n?=?62) follow-up assessments. Of eight intervention group non-completers, six had no preference for art participation. Outcome completion varied between 97% and 77%. Running groups was difficult because of randomisation timing. Effectiveness cannot be determined from this feasibility study but effects sizes suggested art participation may benefit emotional wellbeing, measured on the positive and negative affect schedule, and self-efficacy for Art (d?=?0.24–0.42).

Conclusions: Undertaking a RCT of art participation within stroke rehabilitation was feasible. Art participation may enhance self-efficacy and positively influence emotional wellbeing. These should be outcomes in a future definitive trial. A cluster RCT would ensure art groups could be reliably convened. Fewer measures, and better retention strategies are required.

• Implications for Rehabilitation

• This feasibility randomised controlled trial (RCT) showed that recruiting and retaining stroke survivors in an RCT of a visual arts participation intervention within stroke rehabilitation was feasible.

• Preference to participate in art activities may influence recruitment and drop-out rates, and should be addressed and evaluated fully.

• Art participation as part of rehabilitation may improve some aspects of post-stroke wellbeing, including positive affect and self-efficacy for art.

• A future definitive cluster RCT would facilitate full evaluation of the value art participation can add to rehabilitation.

     

Development of specific receptors for N-formylated chemotactic peptides in a human monocyte cell line stimulated with lymphokines

A human monocyte-like cell line, U937, when grown in continuous culture, does not secrete lysosomal enzymes or migrate towards chemotactic factors. When the cells are stimulated by lymphokines, however, they develop the ability both to migrate directionally and to secrete enzymes in response to several types of chemoattractants. The development, by stimulated cells, of chemotactic and secretory responses to one class of chemoattractants, the N- formylated peptides, is accompanied by the appearance on the cells of specific binding sites for these substances. Using tritiated N-formyl- methionyl-leueyl-phenylalanine (fMet-Leu-[(3)H]Phe) as a ligand, it was determined that unstimulated U937 cells possess no detectable binding sites. However, after stimulation with lymphocyte culture supernates for 24, 48, and 72 h, they developed 4,505 (+/-) 1,138, 22,150(+/-) 4,030, and 37,200 (+/-) 8,000 sites/cell, respectively. The dissociation constants for the interaction of fMet-Leu-[SH]Phe with the binding sites were approximately the same regardless of stimulation time and ranged between 15 and 30 nM. The binding of fMet-Leu-[(3)H]Phe by stimulated U937 cells was rapid and readily reversed by the addition of a large excess of unlabeled peptide. The affinity of a series of N-formylated peptides for binding to U937 cells exactly reflected the potency of the peptides in inducing lysosomal enzyme secretion and chemotaxis. The availability of a continuous human monocytic cell line that can be induced to express receptors for N-formylated peptides will provide a useful tool not only for the characterization of such receptors but also for the delineation of regulatory mechanisms involved in cellular differentiation and the chemotactic response.     

Neurofibromin-deficient Schwann cells secrete a potent migratory stimulus for Nf1+/- mast cells

The NF1 tumor suppressor gene encodes a GTPase-activating protein called neurofibromin that negatively regulates Ras signaling. Mutations in NF1 cause neurofibromatosis type 1 (NF1). The development of neurofibromas, which are complex tumors composed of multiple cell types, is a hallmark of NF1. Somatic inactivation of murine Nf1 in Schwann cells is necessary, but not sufficient, to initiate neurofibroma formation. Neurofibromas occur with high penetrance in mice in which Nf1 is ablated in Schwann cells in the context of a heterozygous mutant (Nf1+/-) microenvironment. Mast cells infiltrate neurofibromas, where they secrete proteins that can remodel the ECM and initiate angiogenesis. Thus, identification of mechanisms responsible for mast cell migration to tumor microenvironments is important for understanding tumorigenesis and for designing potential therapies. Here, we show that homozygous Nf1 mutant (Nf1-/-) Schwann cells secrete Kit ligand (KitL), which stimulates mast cell migration, and that Nf1+/- mast cells are hypermotile in response to KitL. Furthermore, we link hyperactivation of the Ras-class IA-PI3K-Rac2 pathway to increased Nf1+/- mast cell migration. Thus, these studies identify a novel interaction between Nf1-/- Schwann cells and Nf1+/- mast cells that is likely to be important in neurofibroma formation.     

Recent US Case of Variant Creutzfeldt-Jakob Disease—Global Implications

Variant Creutzfeldt-Jakob disease (vCJD) is a rare, fatal prion disease resulting from transmission to humans of the infectious agent of bovine spongiform encephalopathy. We describe the clinical presentation of a recent case of vCJD in the United States and provide an update on diagnostic testing. The location of this patient’s exposure is less clear than those in the 3 previously reported US cases, but strong evidence indicates that exposure to contaminated beef occurred outside the United States more than a decade before illness onset. This case exemplifies the persistent risk for vCJD acquired in unsuspected geographic locations and highlights the need for continued global surveillance and awareness to prevent further dissemination of vCJD.     

A prospective clinicopathologic study of dose-modified CODOX-M/IVAC in patients with sporadic Burkitt lymphoma defined using cytogenetic and immunophenotypic criteria (MRC/NCRI LY10 trial)

This prospective study aimed to develop reproducible diagnostic criteria for sporadic Burkitt lymphoma (BL), applicable to routine practice, and to evaluate the efficacy of dose-modified (dm) CODOX-M/IVAC in patients diagnosed using these criteria. The study was open to patients with an aggressive B-cell lymphoma with an MKI67 fraction approaching 100%. Immunophenotype and fluorescent in situ hybridization (FISH) were used to separate BL from other aggressive B-cell lymphomas. BL was characterized by the presence of a cMYC rearrangement as a sole cytogenetic abnormality occurring in patients with a germinal center phenotype with absence of BCL-2 expression and abnormal TP53 expression. A total of 128 patients were eligible for the study, of whom 58 were considered to have BL and 70 to have diffuse large B-cell lymphoma (DLBCL). There were 110 clinically fit patients who received dmCODOX-M (methotrexate, dose 3 g/m(2)) with or without IVAC according to risk group. The 2-year progression-free survival was 64% (95% confidence interval [CI] 51%-77%) for BL, 55% (95% CI 42%-66%) for DLBCL, 85% (95% CI 73%-97%) for low risk, and 49% (95% CI 38%-60%) for high-risk patients. The observed differences in outcome and other clinical features validate the proposed diagnostic criteria. Compared with the previous trial LY06 with full-dose methotrexate (6.7 g/m(2)), there was a reduction in toxicity with comparable outcomes. This study was registered at www.clinicaltrials.gov as NCT00040690.