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Study Objectives To examine whether drivers are aware of sleepiness and associated symptoms, and how subjective reports predict driving impairment and physiological drowsiness. Methods Sixteen shift workers (19-65y; 9 women) drove an instrumented vehicle for 2-hours on a closed-loop track after a night of sleep and a night of work. Subjective sleepiness/symptoms were rated every 15-minutes. Severe and moderate driving impairment was defined by emergency brake manoeuvres and lane deviations, respectively. Physiological drowsiness was defined by eye closures (Johns Drowsiness Scores, JDS) and EEG-based microsleep events. Results All subjective ratings increased post night-shift (p0.81, p0.8), while moderate ocular-based drowsiness was predicted with fair-to-good accuracy (AUC>0.62). KSS, likelihood of falling asleep, ocular symptoms and ‘nodding off’ predicted microsleep events, with fair-to-good accuracy (AUC 0.65-0.73). Conclusions Drivers are aware of sleepiness, and many self-reported sleepiness symptoms predicted subsequent driving impairment/physiological drowsiness. Drivers should self-assess a wide range of sleepiness symptoms and stop driving when these occur to reduce the escalating risk of road crashes due to drowsiness.

Approximately 30% of elderly adults are cognitively unimpaired at time of death despite the presence of Alzheimer’s disease neuropathology at autopsy. Studying individuals who are resilient to the cognitive consequences of Alzheimer’s disease neuropathology may uncover novel therapeutic targets to treat Alzheimer’s disease. It is well established that there are sex differences in response to Alzheimer’s disease pathology, and growing evidence suggests that genetic factors may contribute to these differences. Taken together, we sought to elucidate sex-specific genetic drivers of resilience. We extended our recent large scale genomic analysis of resilience in which we harmonized cognitive data across four cohorts of cognitive ageing, in vivo amyloid PET across two cohorts, and autopsy measures of amyloid neuritic plaque burden across two cohorts. These data were leveraged to build robust, continuous resilience phenotypes. With these phenotypes, we performed sex-stratified [n (males) = 2093, n (females) = 2931] and sex-interaction [n (both sexes) = 5024] genome-wide association studies (GWAS), gene and pathway-based tests, and genetic correlation analyses to clarify the variants, genes and molecular pathways that relate to resilience in a sex-specific manner. Estimated among cognitively normal individuals of both sexes, resilience was 20–25% heritable, and when estimated in either sex among cognitively normal individuals, resilience was 15–44% heritable. In our GWAS, we identified a female-specific locus on chromosome 10 [rs827389, β (females) = 0.08, P (females) = 5.76 × 10−09, β (males) = −0.01, P(males) = 0.70, β (interaction) = 0.09, P (interaction) = 1.01 × 10−04] in which the minor allele was associated with higher resilience scores among females. This locus is located within chromatin loops that interact with promoters of genes involved in RNA processing, including GATA3. Finally, our genetic correlation analyses revealed shared genetic architecture between resilience phenotypes and other complex traits, including a female-specific association with frontotemporal dementia and male-specific associations with heart rate variability traits. We also observed opposing associations between sexes for multiple sclerosis, such that more resilient females had a lower genetic susceptibility to multiple sclerosis, and more resilient males had a higher genetic susceptibility to multiple sclerosis. Overall, we identified sex differences in the genetic architecture of resilience, identified a female-specific resilience locus and highlighted numerous sex-specific molecular pathways that may underly resilience to Alzheimer’s disease pathology. This study illustrates the need to conduct sex-aware genomic analyses to identify novel targets that are unidentified in sex-agnostic models. Our findings support the theory that the most successful treatment for an individual with Alzheimer’s disease may be personalized based on their biological sex and genetic context.

OBJECTIVE: Studies use different instruments to measure cognitirating cognitive tests permit direct comparisons of individuals across studies and pooling data for joint analyses. METHOD: We began our legacy item bank with data from the Adult Changes in Thought study (n = 5,546), the Alzheimer’s Disease Neuroimaging Initiative (n = 3,016), the Rush Memory and Aging Project (n = 2,163), and the Religious on such as the Mini-Mental State Examination, the Alzheimer’s Disease Assessment Scale–Cognitive Subscale, the Wechsler Memory Scale, and the Boston Naming Test. CocalibOrders Study (n = 1,456). Our workflow begins with categorizing items administered in each study as indicators of memory, executive functioning, language, visuospatial functioning, or none of these domains. We use confirmatory factor analysis models with data from the most recent visit on the pooled sample across these four studies for cocalibration and derive item parameters for all items. Using these item parameters, we then estimate factor scores along with corresponding standard errors for each domain for each study. We added additional studies to our pipeline as available and focused on thorough consideration of candidate anchor items with identical content and administration methods across studies. RESULTS: Prestatistical harmonization steps such qualitative and quantitative assessment of granular cognitive items and evaluating factor structure are important steps when trying to cocalibrate cognitive scores across studies. We have cocalibrated cognitive data and derived scores for four domains for 76,723 individuals across 10 studies. CONCLUSIONS: We have implemented a large-scale effort to harmonize and cocalibrate cognitive domain scores across multiple studies of cognitive aging. Scores on the same metric facilitate meta-analyses of cognitive outcomes across studies or the joint analysis of individual data across studies. Our systematic approach allows for cocalibration of additional studies as they become available and our growing item bank enables robust investigation of cognition in the context of aging and dementia.

The morning commute home is an especially vulnerable time for workers engaged in night shift work due to the heightened risk of experiencing drowsy driving. One strategy to manage this risk is to monitor the driver's state in real time using an in vehicle monitoring system and to alert drivers when they are becoming sleepy. The primary objective of this study is to build and evaluate predictive models for drowsiness events occurring in morning drives using a variety of physiological and performance data gathered under a real driving scenario. We used data collected from 16 night shift workers who drove an instrumented vehicle for approximately two hours on a test track on two occasions: after a night shift and after a night of rest. Drowsiness was defined by two outcome events: performance degradation (Lane-Crossing models) and electroencephalogram (EEG) characterized sleep episodes (Microsleep Models). For each outcome, we assessed the accuracy of sets of predictors, including or not including a driver factor, eyelid measures, and driving performance measures. We also compared the predictions using different time intervals relative to the events (e.g., 1-min prior to the event through 10-min prior). By examining the Area Under the receiver operating characteristic Curve (AUC), accuracy, sensitivity, and specificity of the predictive models, the results showed that the inclusion of an individual driver factor improved AUC and prediction accuracy for both outcomes. Eyelid measures improved the prediction for the Lane-Crossing models, but not for Microsleep models. Prediction performance was not changed by adding driving performance predictors or by increasing the time to the event for either outcome. The best models for both measures of drowsiness were those considering driver individual differences and eyelid measures, suggesting that these indicators should be strongly considered when predicting drowsiness events. The results of this paper can benefit the development of real-time drowsiness detection and help to manage drowsiness to avoid related motor-vehicle crashes and loss.

Background: Vascular disease is a risk factor for Alzheimer’s disease (AD) and related dementia in older adults. Retinal artery/vein occlusion (RAVO) is an ophthalmic complication of systemic vascular pathology. Whether there are associations between RAVO and dementia risk is unknown. Objective: To determine whether RAVOs are associated with an increased risk of developing vascular dementia or AD. Methods: Data from Adult Changes in Thought (ACT) study participants were analyzed. This prospective, population-based cohort study followed older adults (age ≥65 years) who were dementia-free at enrollment for development of vascular dementia or AD based on research criteria. RAVO diagnoses were extracted from electronic medical records. Cox-regression survival analyses were stratified by APOE ɛ4 genotype and adjusted for demographic and clinical factors. Results: On review of 41,216 person-years (4,743 participants), 266 (5.6%) experienced RAVO. APOE ɛ4 carriers who developed RAVO had greater than four-fold higher risk for developing vascular dementia (Hazard Ratio [HR] 4.54, 95% Confidence Interval [CI] 1.86, 11.10, p = 0.001). When including other cerebrovascular disease (history of carotid endarterectomy or transient ischemic attack) in the model, the risk was three-fold higher (HR 3.06, 95% CI 1.23, 7.62). No other conditions evaluated in the secondary analyses were found to confound this relationship. There was no effect in non-APOE ɛ4 carriers (HR 1.03, 95% CI 0.37, 2.80). There were no significant associations between RAVO and AD in either APOE group. Conclusion: Older dementia-free patients who present with RAVO and carry the APOE ɛ4 allele appear to be at higher risk for vascular dementia.

Background/Objectives To determine the predictors of narrow angle detection in a United States population-based cohort. Materials and methods This was a retrospective cohort study using the Massachusetts All-Payer Claims Database. Demographic information of all patients and eye care provider information during the years 2011–2015 were extracted from Massachusetts All Payers Claims Data. All payers who received eye care during 1/1/2012–12/31/2015 without any previous eye visit during 2011 were included in the analyses. Laser peripheral iridotomy was identified by Current Procedural Terminology code 66761. Narrow angle detection was defined as the diagnosis of narrow angles by diagnosis code followed by a laser peripheral iridotomy procedure. Different predictors of narrow angle detection were evaluated using Kaplan–Meier curves with the log rank and Cox regression modeling. Results A total of 1,082,144 patients were included. The hazard ratio of narrow angle detection increased with age compared to the reference group of 0–10 years: 21–30 years of age (hazard ratio = 4.5), 31–40 (10.5), 41–50 (27.9), 51–60 (46.1), 61–70 (68.4), 71–80 (56.8) (all p Conclusion Older age and female sex are associated with narrow angles. The rate of narrow angle detection was significantly higher if patients are seen by ophthalmologists compared to optometrists only. Evaluation with an ophthalmologist may be important for patients at high risks for developing primary angle closure glaucoma.

Approximately 30% of older adults exhibit the neuropathologic features of Alzheimer’s disease (AD) without signs of cognitive impairment. Yet, little is known about the genetic factors that allow these potentially resilient individuals to remain cognitively normal in the face of substantial neuropathology. We performed a large, genome-wide association study (GWAS) of two previously validated metrics of cognitive resilience quantified using a latent variable modeling approach and representing better-than-predicted cognitive performance for a given level of neuropathology. Data were harmonized across 5,108 participants from a clinical trial of AD and three longitudinal cohort studies of cognitive aging. All analyses were run across all participants and repeated restricting the sample to individuals with normal cognition to identify variants at the earliest stages of disease. As expected, all resilience metrics were genetically correlated with cognitive performance and education attainment traits (p-values−20), and we observed novel correlations with neuropsychiatric conditions (p-values−4). Notably, neither resilience metric was genetically correlated with clinical AD (p-values>0.42) nor associated withAPOE(p-values>0.13). In single variant analyses, we observed a genome-wide significant locus among participants with normal cognition on chromosome 18 upstream ofATP8B1(index SNP rs2571244, MAF=0.08, p=2.3×10−8). The top variant at this locus (rs2571244) was significantly associated with methylation in prefrontal cortex tissue at multiple CpG sites, including one just upstream ofATPB81(cg19596477; p=2×10−13). Overall, this comprehensive genetic analysis of resilience implicates a putative role of vascular risk, metabolism, and mental health in protection from the cognitive consequences of neuropathology, while also providing evidence for a novel resilience gene along the bile acid metabolism pathway.Furthermore, the genetic architecture of resilience appears to be distinct from that of clinical AD, suggesting that a shift in focus to molecular contributors to resilience may identify novel pathways for therapeutic targets.

Key Points Question Is cataract extraction associated with reduced risk of developing dementia? Findings In this cohort study assessing 3038 adults 65 years of age or older with cataract enrolled in the Adult Changes in Thought study, participants who underwent cataract extraction had lower risk of developing dementia than those who did not have cataract surgery after controlling for numerous additional risks. In comparison, risk of dementia did not differ between participants who did or did not undergo glaucoma surgery, which does not restore vision. Meaning This study suggests that cataract extraction is associated with lower risk of developing dementia among older adults., Importance Visual function is important for older adults. Interventions to preserve vision, such as cataract extraction, may modify dementia risk. Objective To determine whether cataract extraction is associated with reduced risk of dementia among older adults. Design, Setting, and Participants This prospective, longitudinal cohort study analyzed data from the Adult Changes in Thought study, an ongoing, population-based cohort of randomly selected, cognitively normal members of Kaiser Permanente Washington. Study participants were 65 years of age or older and dementia free at enrollment and were followed up biennially until incident dementia (all-cause, Alzheimer disease, or Alzheimer disease and related dementia). Only participants who had a diagnosis of cataract or glaucoma before enrollment or during follow-up were included in the analyses (ie, a total of 3038 participants). Data used in the analyses were collected from 1994 through September 30, 2018, and all data were analyzed from April 6, 2019, to September 15, 2021. Exposures The primary exposure of interest was cataract extraction. Data on diagnosis of cataract or glaucoma and exposure to surgery were extracted from electronic medical records. Extensive lists of dementia-related risk factors and health-related variables were obtained from study visit data and electronic medical records. Main Outcomes and Measures The primary outcome was dementia as defined by Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria. Multivariate Cox proportional hazards regression analyses were conducted with the primary outcome. To address potential healthy patient bias, weighted marginal structural models incorporating the probability of surgery were used and the association of dementia with glaucoma surgery, which does not restore vision, was evaluated. Results In total, 3038 participants were included (mean [SD] age at first cataract diagnosis, 74.4 (6.2) years; 1800 women (59%) and 1238 men (41%); and 2752 (91%) self-reported White race). Based on 23 554 person-years of follow-up, cataract extraction was associated with significantly reduced risk (hazard ratio, 0.71; 95% CI, 0.62-0.83; P, This cohort study analyzing data obtained from the Adult Changes in Thought study assesses whether cataract extraction is associated with reduced risk of dementia among adults 65 years of age or older.

Why are some individuals able to tolerate severe Alzheimer’s disease pathology without experiencing dementia? Dumitrescu et al. perform a large genome-wide analysis of resilience to Alzheimer’s disease and highlight several biological pathways that may protect the brain from the downstream consequences of amyloidosis., Approximately 30% of older adults exhibit the neuropathological features of Alzheimer’s disease without signs of cognitive impairment. Yet, little is known about the genetic factors that allow these potentially resilient individuals to remain cognitively unimpaired in the face of substantial neuropathology. We performed a large, genome-wide association study (GWAS) of two previously validated metrics of cognitive resilience quantified using a latent variable modelling approach and representing better-than-predicted cognitive performance for a given level of neuropathology. Data were harmonized across 5108 participants from a clinical trial of Alzheimer’s disease and three longitudinal cohort studies of cognitive ageing. All analyses were run across all participants and repeated restricting the sample to individuals with unimpaired cognition to identify variants at the earliest stages of disease. As expected, all resilience metrics were genetically correlated with cognitive performance and education attainment traits (P-values < 2.5 × 10−20), and we observed novel correlations with neuropsychiatric conditions (P-values < 7.9 × 10−4). Notably, neither resilience metric was genetically correlated with clinical Alzheimer’s disease (P-values > 0.42) nor associated with APOE (P-values > 0.13). In single variant analyses, we observed a genome-wide significant locus among participants with unimpaired cognition on chromosome 18 upstream of ATP8B1 (index single nucleotide polymorphism rs2571244, minor allele frequency = 0.08, P = 2.3 × 10−8). The top variant at this locus (rs2571244) was significantly associated with methylation in prefrontal cortex tissue at multiple CpG sites, including one just upstream of ATPB81 (cg19596477; P = 2 × 10−13). Overall, this comprehensive genetic analysis of resilience implicates a putative role of vascular risk, metabolism, and mental health in protection from the cognitive consequences of neuropathology, while also providing evidence for a novel resilience gene along the bile acid metabolism pathway. Furthermore, the genetic architecture of resilience appears to be distinct from that of clinical Alzheimer’s disease, suggesting that a shift in focus to molecular contributors to resilience may identify novel pathways for therapeutic targets.

Study objectives Sleep is important for consolidation of hippocampus-dependent memories. It is hypothesized that the temporal sequence of nonrapid eye movement (NREM) sleep and rapid eye movement (REM) sleep is critical for the weakening of nonadaptive memories and the subsequent transfer of memories temporarily stored in the hippocampus to more permanent memories in the neocortex. A great body of evidence supporting this hypothesis relies on behavioral, pharmacological, neural, and/or genetic manipulations that induce sleep deprivation or stage-specific sleep deprivation. Methods We exploit an experimental model of circadian desynchrony in which intact animals are not deprived of any sleep stage but show fragmentation of REM and NREM sleep within nonfragmented sleep bouts. We test the hypothesis that the shortening of NREM and REM sleep durations post-training will impair memory consolidation irrespective of total sleep duration. Results When circadian-desynchronized animals are trained in a hippocampus-dependent contextual fear-conditioning task they show normal short-term memory but impaired long-term memory consolidation. This impairment in memory consolidation is positively associated with the post-training fragmentation of REM and NREM sleep but is not significantly associated with the fragmentation of total sleep or the total amount of delta activity. We also show that the sleep stage fragmentation resulting from circadian desynchrony has no effect on hippocampus-dependent spatial memory and no effect on hippocampus-independent cued fear-conditioning memory. Conclusions Our findings in an intact animal model, in which sleep deprivation is not a confounding factor, support the hypothesis that the stereotypic sequence and duration of sleep stages play a specific role in long-term hippocampus-dependent fear memory consolidation.

The effects of phosphorylation of the tyrosine residue in the highly conserved DRY motif expressed in the putative second cytoplasmic loop of the μ-opioid receptor were assessed after expression in human embryonic kidney (HEK) 293 cells. Tyrosine kinase activation by epidermal growth factor (EGF) or hydrogen peroxide treatment effectively increased phosphorylation of the tyrosine-166 in the μ-opioid receptor (MOR-Tyr166p) as measured by a novel phosphoselective antibody. We were surprised to find that the increase in MOR-Tyr166p immunoreactivity (ir) required coactivation by the opioid agonist [d-Ala2,methyl-Phe4,Gly5-ol]enkephalin (DAMGO), as demonstrated by both Western blot imaging of membrane proteins and confocal microscopy of transfected cells; MOR-Tyr166p-ir did not significantly increase after either DAMGO, EGF, or H2O2 treatment alone. The increase in MOR-Tyr166p-ir was blocked by pretreatment with the opioid antagonist naloxone or the Src kinase inhibitor 4-amino-5-(4-chloro-phenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine. Consistent with these data, mutation of the tyrosine-166 to phenylalanine blocked the increased immunoreactivity, and untransfected HEK293 cells did not increase MOR-Tyr166p-ir after treatment. DAMGO increased guanosine 5′-O-(3-[35S]thio)triphosphate ([35S]GTPγS) binding to membranes from cells expressing wild-type MOR or MOR-Y166F receptors in a dose-dependent manner. Pretreatment of the wild-type MOR-expressing cells with the combination of DAMGO and EGF completely blocked subsequent DAMGO stimulation of [35S]GTPγS binding membranes, whereas [35S]GTPγS binding to membranes from cells expressing mutated MOR(Y166F) was only partially inhibited. These results suggest that G-protein activation as measured by [35S]GTPγS binding can be regulated by DAMGO and EGF by convergent mechanisms and support the hypothesis that tyrosine phosphorylation within the DRY motif may reduce μ-opioid receptor–G-protein coupling efficiency.

SummarySleep is consistently concentrated to a specific time of the day. Its timing and consolidation depend on the interplay between a homeostatic and a circadian process of sleep regulation [1–3]. Sleep propensity rises as a homeostatic response to increasing wake time, whereas a circadian clock determines the specific time when sleep will probably occur. This two-process regulation of sleep also determines which specific sleep stage will be manifested, and the circadian process governs tightly the manifestation of rapid eye movement sleep (REMS) [1, 4]. The role of the hypothalamic suprachiasmatic nucleus (SCN) in the circadian gating of sleep and wakefulness has been unequivocally established by lesion studies [5], but its role in the timing of specific sleep stages has remained unknown. Using a forced desynchrony paradigm that induces the stable dissociation of the ventrolateral (vl) and dorsomedial (dm) SCN, and a jetlag paradigm that induces desynchronization between these SCN subregions, we show that the SCN can time the occurrence of specific sleep stages. Specifically, the circadian regulation of REMS is associated with clock gene expression within the dmSCN. We provide the first neurophysiological model for the disruption of sleep architecture that may result from temporal challenges such as rotational-shift work and jetlag.

Proper functioning of the human circadian timing system is crucial to physical and mental health. Much of what we know about this system is based on experimental protocols that induce the desynchronization of behavioral and physiological rhythms within individual subjects, but the neural (or extraneural) substrates for such desynchronization are unknown. We have developed an animal model of human internal desynchrony in which rats are exposed to artificially short (22-h) light–dark cycles. Under these conditions, locomotor activity, sleep–wake, and slow-wave sleep (SWS) exhibit two rhythms within individual animals, one entrained to the 22-h light–dark cycle and the other free-running with a period >24 h (τ >24 h ). Whereas core body temperature showed two rhythms as well, further analysis indicates this variable oscillates more according to the τ >24 h rhythm than to the 22-h rhythm, and that this oscillation is due to an activity-independent circadian regulation. Paradoxical sleep (PS), on the other hand, shows only one free-running rhythm. Our results show that, similarly to humans, ( i ) circadian rhythms can be internally dissociated in a controlled and predictable manner in the rat and ( ii ) the circadian rhythms of sleep–wake and SWS can be desynchronized from the rhythms of PS and core body temperature within individual animals. This model now allows for a deeper understanding of the human timekeeping mechanism, for testing potential therapies for circadian dysrhythmias, and for studying the biology of PS and SWS states in a neurologically intact model.

Night-shift workers are at high risk of drowsiness-related motor vehicle crashes as a result of circadian disruption and sleep restriction. However, the impact of actual night-shift work on measures of drowsiness and driving performance while operating a real motor vehicle remains unknown. Sixteen night-shift workers completed two 2-h daytime driving sessions on a closed driving track at the Liberty Mutual Research Institute for Safety: (i) a postsleep baseline driving session after an average of 7.6 ± 2.4 h sleep the previous night with no night-shift work, and (ii) a postnight-shift driving session following night-shift work. Physiological measures of drowsiness were collected, including infrared reflectance oculography, electroencephalography, and electrooculography. Driving performance measures included lane excursions, near-crash events, and drives terminated because of failure to maintain control of the vehicle. Eleven near-crashes occurred in 6 of 16 postnight-shift drives (37.5%), and 7 of 16 postnight-shift drives (43.8%) were terminated early for safety reasons, compared with zero near-crashes or early drive terminations during 16 postsleep drives (Fishers exact: P = 0.0088 and P = 0.0034, respectively). Participants had a significantly higher rate of lane excursions, average Johns Drowsiness Scale, blink duration, and number of slow eye movements during postnight-shift drives compared with postsleep drives (3.09/min vs. 1.49/min; 1.71 vs. 0.97; 125 ms vs. 100 ms; 35.8 vs. 19.1; respectively, P < 0.05 for all). Night-shift work increases driver drowsiness, degrading driving performance and increasing the risk of near-crash drive events. With more than 9.5 million Americans working overnight or rotating shifts and one-third of United States commutes exceeding 30 min, these results have implications for traffic and occupational safety.

Posttraumatic elbow stiffness is a common problem that is often difficult to manage. The goal of treatment is to restore a functional range of elbow motion (> or =30 degrees to 130 degrees ). Nonsurgical treatment includes physical therapy and splinting. If nonsurgical treatment has failed, the type of surgical treatment required depends on the extent of degenerative changes. When degenerative changes are absent or mild, soft-tissue release offers reliable increases in elbow motion. When moderate degenerative changes exist within the joint, debridement arthroplasty of osteophytes and soft tissue has shown some success with increase in joint motion. With advanced degenerative changes, the therapeutic options are more limited. Results from biologic resurfacing arthroplasty are unpredictable, and total elbow arthroplasty should be reserved for the lower-demand elbow in a physiologically older individual.

Sleep is a defining trait in animals. Although the function(s) of sleep remain elusive, it is clear that sleep is necessary for survival and its timing precisely regulated. Two processes operate to determine when sleep will occur and how intense it will be. The homeostatic process determines the buildup of sleep pressure that results from extended wakefulness, and the circadian process regulates sleep pressure according to a circadian clock located in the suprachiasmatic nucleus of the hypothalamus. This chapter discusses the experimental evidence for these regulatory processes. In mammals, the interplay between the homeostatic and circadian regulatory limbs not only determines the timing and intensity of sleep but also leads to a stereotypic temporal organization of sleep stages. Whereas increased homeostatic drive favors slow-wave sleep, increased circadian drive favors rapid eye movement (REM) sleep. Environmental challenges that disrupt the timing of sleep affect its amount as well as its quality.

Because time-of-day effects on sleepiness interact with duration of prior waking, the commute home following a night shift is an especially vulnerable time for night shift workers. The current study aimed to explore the impact of night shift work on critical driving events as well as to explore physiological indices leading up to these events. Sixteen healthy night shift workers (18-65 years) each participated in two 2-hour driving sessions in an instrumented vehicle on a driving track. A baseline driving session was conducted following a night of rest, while another session was conducted following a night of shift work. Objective physiological measurements of drowsiness were monitored and collected continuously throughout the drive session as well as different measures of driving performance. Following the night-shift, drivers had higher Johns Drowsiness Scores (based on ocular measures) and were more likely to experience lane excursion events and investigator-initiated braking events than following a night’s rest. While they also reported increasing failures in lane keeping ability, the pattern was not always consistent with actual observed data. The implications for countermeasures are discussed.

To define the roles of the calmodulin-stimulated adenylyl cyclases (AC1 and AC8) in morphine-induced analgesia, tolerance, physical dependence, and conditioned place preference, we used mice having targeted disruptions of either the AC1 or AC8 genes or both genes [double knockout mice (DKO)]. Mice lacking either AC1 or AC8 genes or DKO did not differ from wild-type mice in short-term antinociceptive responses to morphine measured in the tail-flick analgesia assay. Morphine tolerance that developed immediately within 3 h of morphine administration (10 mg/kg s.c.) was significantly attenuated in DKO mice and AC8 single knockout mice. Tolerance induced continually by daily injections of morphine (10 mg/kg s.c.) was also reduced in DKO mice. In DKO mice continually treated with morphine, there was a significant reduction in withdrawal behaviors, including reduced wet-dog shakes and forepaw tremor after naloxone injection (10 mg/kg i.p.). Morphine produced hyperlocomotion and conditioned place preference in wild-type mice, whereas DKO mice displayed significantly less hyperlocomotion and conditioned place preference. Furthermore, the significant increase in phosphorylated cAMP-response element binding protein (CREB) staining in ventral tegmental area induced by long-term morphine treatment was not evident in DKO mice, suggesting that CREB activation by morphine requires cAMP generated by AC1 and AC8. These results support the hypothesis that calmodulin-stimulated adenylyl cyclases are important mediators of the neuronal responses to morphine.

To compare the mechanical effectiveness of three different techniques for stabilization of transverse fractures of the patella.Cadaveric knees were used to model acute fractures of the patella. To test three treatment techniques in pairs of knees, specimen pairs were assigned randomly to a set of predetermined treatment pairs so as to provide equal numbers of paired and unpaired data sets. Results then were analyzed using a two-way analysis of variance.The treatment techniques used are widely applicable in the clinical setting for the treatment of transverse fractures of the patella. No specialized equipment or training is required for the general or subspecialized orthopaedic surgeon.None.Fractures were created in eighteen knees (nine pairs) and repaired by one of three techniques: (a) modified tension band (AO technique); (b) two parallel 4.5-millimeter interfragmentary lag screws; or (c) a new technique using four-millimeter cannulated lag screws with a tension band wired through the screws.In mechanical testing, the amount of interfragmentary separation in simulated knee extension and the maximum load to failure at 45 degrees of flexion were measured.Fractures stabilized with a modified tension band were found to displace significantly more than those fixed with screws alone or screws plus a tension band in simulated knee extensions (p0.05). The fractures fixed with the cannulated screws plus the tension band failed at higher loads (mean = 732 newtons) than those stabilized with screws alone (mean = 554 newtons, p = 0.06) or those with a modified tension band (mean = 395 newtons, p0.05).Combining interfragmentary screw fixation with the tension band principle appears to provide improved stability over the modified tension band or screws alone for transverse patella fractures. Cannulated screws allow for simple, reliable addition of a tension band to screw fixation.