The Human Endogenous Circadian System Causes Greatest Platelet Activation during the Biological Morning Independent of Behaviors

Platelets are involved in the thromboses that are central to myocardial infarctions and ischemic strokes. Such adverse cardiovascular events have day/night patterns with peaks in the morning (~9 AM), potentially related to endogenous circadian clock control of platelet activation. The objective was to test if the human endogenous circadian system influences (1) platelet function and (2) platelet response to standardized behavioral stressors. We also aimed to compare the magnitude of any effects on platelet function caused by the circadian system with that caused by varied standardized behavioral stressors, including mental arithmetic, passive postural tilt and mild cycling exercise.We studied 12 healthy adults (6 female) who lived in individual laboratory suites in dim light for 240 h, with all behaviors scheduled on a 20-h recurring cycle to permit assessment of endogenous circadian function independent from environmental and behavioral effects including the sleep/wake cycle. Circadian phase was assessed from core body temperature. There were highly significant endogenous circadian rhythms in platelet surface activated glycoprotein (GP) IIb-IIIa, GPIb and P-selectin (6-17% peak-trough amplitudes; p ≤ 0.01). These circadian peaks occurred at a circadian phase corresponding to 8-9 AM. Platelet count, ATP release, aggregability, and plasma epinephrine also had significant circadian rhythms but with later peaks (corresponding to 3-8 PM). The circadian effects on the platelet activation markers were always larger than that of any of the three behavioral stressors.These data demonstrate robust effects of the endogenous circadian system on platelet activation in humans--independent of the sleep/wake cycle, other behavioral influences and the environment. The 9 AM timing of the circadian peaks of the three platelet surface markers, including platelet surface activated GPIIb-IIIa, the final common pathway of platelet aggregation, suggests that endogenous circadian influences on platelet function could contribute to the morning peak in adverse cardiovascular events as seen in many epidemiological studies

Natural parenting : back to basics in infant care

Peer reviewe

Primary Human mDC1, mDC2, and pDC Dendritic Cells Are Differentially Infected and Activated by Respiratory Syncytial Virus

Respiratory syncytial virus (RSV) causes recurrent infections throughout life. Vaccine development may depend upon understanding the molecular basis for induction of ineffective immunity. Because dendritic cells (DCs) are critically involved in early responses to infection, their interaction with RSV may determine the immunological outcome of RSV infection. Therefore, we investigated the ability of RSV to infect and activate primary mDCs and pDCs using recombinant RSV expressing green fluorescent protein (GFP). At a multiplicity of infection of 5, initial studies demonstrated ∼6.8% of mDC1 and ∼0.9% pDCs were infected. We extended these studies to include CD1c−CD141+ mDC2, finding mDC2 infected at similar frequencies as mDC1. Both infected and uninfected cells upregulated phenotypic markers of maturation. Divalent cations were required for infection and maturation, but maturation did not require viral replication. There is evidence that attachment and entry/replication processes exert distinct effects on DC activation. Cell-specific patterns of RSV-induced maturation and cytokine production were detected in mDC1, mDC2, and pDC. We also demonstrate for the first time that RSV induces significant TIMP-2 production in all DC subsets. Defining the influence of RSV on the function of selected DC subsets may improve the likelihood of achieving protective vaccine-induced immunity

Full central neurokinin-1 receptor blockade is required for efficacy in depression: Evidence from orvepitant clinical studies

10.1177/0269881113480990Journal of Psychopharmacology275424-434JOPS

Clinical value of early partial symptomatic improvement in the prediction of response and remission during short-term treatment trials in 3369 subjects with bipolar I or II depression

OBJECTIVE: To evaluate the clinical value of early partial symptomatic improvement in predicting the probability of response during the short-term treatment of bipolar depression. METHODS: Blinded data from 10 multicenter, randomized, double-blind, placebo-controlled trials in bipolar I or II depression were used to determine if early improvement (≥20% reduction in depression symptom severity after 14days of treatment) predicted later short-term response or remission. Sensitivity, specificity, efficiency, and positive and negative predictive values (PPV, NPV) were calculated using an intent to treat analysis of individual and pooled study data. RESULTS: 1913 patients were randomized to active compounds (aripiprazole, lamotrigine, olanzapine/olanzapine-fluoxetine, and quetiapine), and 1456 to placebo. In the pooled positive studies, early improvement predicted response and remission with high sensitivity (86% and 88%, respectively), but rates of false positives were high (53% and 59%, respectively). Pooled negative predictive values for response/remission (i.e. confidence in knowing the drug will not result in response or remission) were 74% and 82%, respectively, with low rates of false negatives (14% and 12%, respectively). CONCLUSION: Early improvement in an individual patient does not appear to be a reliable predictor of eventual response or remission due to an unacceptably high false positive rate. However, the absence of early improvement appears to be a highly reliable predictor of eventual non-response, suggesting that clinicians can have confidence in knowing when a drug is not going to work during short-term treatment. Patients who fail to demonstrate early improvement within the first two weeks of treatment may benefit from a change in therapy