A new molecular method for rapid etiological diagnosis of sepsis with improved performance.

The value of blood cultures for confirming the clinical diagnosis of sepsis is suboptimal. There is growing interest in the potential of real-time PCR technology by detection of minute amounts of pathogen DNA in patient blood samples with results available within 4-6 h. Adopting a two-step approach, we evaluated the compliance of two versions of the MicrobScan assay on a total of 748 patients with suspected bloodstream infections. The results obtained with a second version of the MicrobScan assay are characterized by increased specificity (from 95.1 to 98.2%) and sensitivity (from 76.7 to 85.1), increased throughput and the possibility of simultaneously testing different kinds of samples collected from the potential sites of infection and utilizing different syndromic panels.

Genetic analysis of activity, brain and behavioral associations in extended families with heavy genetic loading for bipolar disorder.

BACKGROUND: Disturbed sleep and activity are prominent features of bipolar disorder type I (BP-I). However, the relationship of sleep and activity characteristics to brain structure and behavior in euthymic BP-I patients and their non-BP-I relatives is unknown. Additionally, underlying genetic relationships between these traits have not been investigated. METHODS: Relationships between sleep and activity phenotypes, assessed using actigraphy, with structural neuroimaging (brain) and cognitive and temperament (behavior) phenotypes were investigated in 558 euthymic individuals from multi-generational pedigrees including at least one member with BP-I. Genetic correlations between actigraphy-brain and actigraphy-behavior associations were assessed, and bivariate linkage analysis was conducted for trait pairs with evidence of shared genetic influences. RESULTS: More physical activity and longer awake time were significantly associated with increased brain volumes and cortical thickness, better performance on neurocognitive measures of long-term memory and executive function, and less extreme scores on measures of temperament (impulsivity, cyclothymia). These associations did not differ between BP-I patients and their non-BP-I relatives. For nine activity-brain or activity-behavior pairs there was evidence for shared genetic influence (genetic correlations); of these pairs, a suggestive bivariate quantitative trait locus on chromosome 7 for wake duration and verbal working memory was identified. CONCLUSIONS: Our findings indicate that increased physical activity and more adequate sleep are associated with increased brain size, better cognitive function and more stable temperament in BP-I patients and their non-BP-I relatives. Additionally, we found evidence for pleiotropy of several actigraphy-behavior and actigraphy-brain phenotypes, suggesting a shared genetic basis for these traits.

An actigraphy study investigating sleep in bipolar I patients, unaffected siblings and controls.

OBJECTIVES: Disturbances in sleep and waking patterns are highly prevalent during mood episodes in bipolar disorder. The question remains whether these disturbances persist during phases of euthymia and whether they are heritable traits of bipolar disorder. The current study investigates objective sleep measures in a large sample of bipolar I patients, non-affected siblings and controls. METHODS: A total of 107 bipolar disorder I patients, 74 non-affected siblings, and 80 controls were included. Sleep was measured with actigraphy over the course of 14 days. Seven sleep parameters were analyzed for group differences and their relationship with age at onset, number of episodes and psychotic symptoms using linear mixed model analysis to account for family dependencies. RESULTS: Patients had a longer sleep duration and later time of sleep offset compared to the non-affected siblings but these differences were entirely attributable to differences in mood symptoms. We found no difference between patients and controls or siblings and controls when the analyses were restricted to euthymic patients. None of the bipolar illness characteristics were associated with sleep. LIMITATIONS: Medication use was not taken into account which may have influenced our findings and controls were younger compared to non-affected siblings. CONCLUSIONS: In the largest study to date, our findings suggest that recovered bipolar I patients and their siblings do not experience clinically significant sleep disturbances. Sleep disturbances are primarily a reflection of current mood state, but are unrelated to the course of the disorder.

Genetic contributions to circadian activity rhythm and sleep pattern phenotypes in pedigrees segregating for severe bipolar disorder.

Abnormalities in sleep and circadian rhythms are central features of bipolar disorder (BP), often persisting between episodes. We report here, to our knowledge, the first systematic analysis of circadian rhythm activity in pedigrees segregating severe BP (BP-I). By analyzing actigraphy data obtained from members of 26 Costa Rican and Colombian pedigrees [136 euthymic (i.e., interepisode) BP-I individuals and 422 non-BP-I relatives], we delineated 73 phenotypes, of which 49 demonstrated significant heritability and 13 showed significant trait-like association with BP-I. All BP-I-associated traits related to activity level, with BP-I individuals consistently demonstrating lower activity levels than their non-BP-I relatives. We analyzed all 49 heritable phenotypes using genetic linkage analysis, with special emphasis on phenotypes judged to have the strongest impact on the biology underlying BP. We identified a locus for interdaily stability of activity, at a threshold exceeding genome-wide significance, on chromosome 12pter, a region that also showed pleiotropic linkage to two additional activity phenotypes.

Amyloid-Beta interaction with mitochondria.

Mitochondrial dysfunction is a hallmark of amyloid-beta(Aß)-induced neuronal toxicity in Alzheimer's disease (AD). The recent emphasis on the intracellular biology of Aß and its precursor protein (AßPP) has led researchers to consider the possibility that mitochondria-associated and/or intramitochondrial Aß may directly cause neurotoxicity. In this paper, we will outline current knowledge of the intracellular localization of both Aß and AßPP addressing the question of how Aß can access mitochondria. Moreover, we summarize evidence from AD postmortem brain as well as cellular and animal AD models showing that Aß triggers mitochondrial dysfunction through a number of pathways such as impairment of oxidative phosphorylation, elevation of reactive oxygen species (ROS) production, alteration of mitochondrial dynamics, and interaction with mitochondrial proteins. In particular, we focus on Aß interaction with different mitochondrial targets including the outer mitochondrial membrane, intermembrane space, inner mitochondrial membrane, and the matrix. Thus, this paper establishes a modified model of the Alzheimer cascade mitochondrial hypothesis.

Serum factors in older individuals change cellular clock properties.

Human aging is accompanied by dramatic changes in daily sleep-wake behavior: Activity shifts to an earlier phase, and the consolidation of sleep and wake is disturbed. Although this daily circadian rhythm is brain-controlled, its mechanism is encoded by cell-autonomous circadian clocks functioning in nearly every cell of the body. In fact, human clock properties measured in peripheral cells such as fibroblasts closely mimic those measured physiologically and behaviorally in the same subjects. To understand better the molecular mechanisms by which human aging affects circadian clocks, we characterized the clock properties of fibroblasts cultivated from dermal biopsies of young and older subjects. Fibroblast period length, amplitude, and phase were identical in the two groups even though behavior was not, thereby suggesting that basic clock properties of peripheral cells do not change during aging. Interestingly, measurement of the same cells in the presence of human serum from older donors shortened period length and advanced the phase of cellular circadian rhythms compared with treatment with serum from young subjects, indicating that a circulating factor might alter human chronotype. Further experiments demonstrated that this effect is caused by a thermolabile factor present in serum of older individuals. Thus, even though the molecular machinery of peripheral circadian clocks does not change with age, some age-related circadian dysfunction observed in vivo might be of hormonal origin and therefore might be pharmacologically remediable.

Combined expression of tau and the Harlequin mouse mutation leads to increased mitochondrial dysfunction, tau pathology and neurodegeneration.

Mitochondrial dysfunction and oxidative stress play an important role in ageing and have been implicated in several age-related neurodegenerative conditions including Alzheimer's disease (AD) and other tauopathies characterized by the presence of intracellular accumulations of the hyperphosphorylated microtubule-associated protein tau. To study the interaction between mitochondrial dysfunction and tau pathology in vivo, we generated a novel mouse model by crossbreeding two existing lines: the Harlequin (Hq) mutant mice which suffer from mitochondrial dysfunction and oxidative stress due to a lack of the mitochondrial apoptosis-inducing factor (AIF), and the P301L tau transgenic mice, a mouse model of human tau pathology. Combined expression of the Hq mouse mutation and the tau transgene in the Tau/Hq double mutant mice led to an increase in tau pathology and apoptotic neurodegeneration when compared to single expression of the two mutations. Neurodegeneration was most prominent in the dentate gyrus and was significantly increased in the cerebellum leading to aggravated motor deficits. Functional activity measurements of the mitochondrial respiratory chain (MRC) in the Tau/Hq mice revealed early decreased activities of multiple MRC complexes and depleted ATP levels which preceded neurodegeneration and elevated oxidative stress markers. These results suggest an age-dependent mutual reinforcement of the tau pathology and mitochondrial dysfunction in vivo, which may contribute to neurodegeneration in patients suffering from AD and other age-related tauopathies.

Systemic and cellular reflections on ageing and the circadian oscillator: a mini-review.

From circulation to digestion to excretion, a circadian clock synchronizes most aspects of mammalian physiology with the solar day. During normal ageing, this daily coordination gradually erodes, and during pathological ageing such erosion is exacerbated. Recent experiments suggest that therapies aimed at sustaining circadian function increase quality of life in elderly patients. Hence, a better understanding of the interactions between the circadian clock and ageing - at both cellular and systemic levels - could lead to direct benefits for aged individuals.

The physiological period length of the human circadian clock in vivo is directly proportional to period in human fibroblasts.

BACKGROUND: Diurnal behavior in humans is governed by the period length of a circadian clock in the suprachiasmatic nuclei of the brain hypothalamus. Nevertheless, the cell-intrinsic mechanism of this clock is present in most cells of the body. We have shown previously that for individuals of extreme chronotype ("larks" and "owls"), clock properties measured in human fibroblasts correlated with extreme diurnal behavior. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we have measured circadian period in human primary fibroblasts taken from normal individuals and, for the first time, compared it directly with physiological period measured in vivo in the same subjects. Human physiological period length was estimated via the secretion pattern of the hormone melatonin in two different groups of sighted subjects and one group of totally blind subjects, each using different methods. Fibroblast period length was measured via cyclical expression of a lentivirally delivered circadian reporter. Within each group, a positive linear correlation was observed between circadian period length in physiology and in fibroblast gene expression. Interestingly, although blind individuals showed on average the same fibroblast clock properties as sighted ones, their physiological periods were significantly longer. CONCLUSIONS/SIGNIFICANCE: We conclude that the period of human circadian behaviour is mostly driven by cellular clock properties in normal individuals and can be approximated by measurement in peripheral cells such as fibroblasts. Based upon differences among sighted and blind subjects, we also speculate that period can be modified by prolonged unusual conditions such as the total light deprivation of blindness.

Identification and early characterization of genetically modified NGF-producing neural stem cells grafted into the injured adult rat brain.

OBJECTIVE: To investigate whether genetically modified mouse neural stem cells (NSC) expressing recombinant human nerve growth factor (rhNGF) and transplanted in chemically injured rat brain, can survive and eventually acquire phenotypic characteristics of early nerve cells. METHODS: Stably high expression of rhNGF in NSC was obtained by a new lentivirus-mediated expression system. To test the effectiveness of hNGF secreted by rhNGF-NSC, hereby we performed either a bioassay for neurite outgrowth in PC12 rat cells or immunoblot analysis for TrkA, the high-affinity NGF receptor, from engineered NSC. rhNGF and mock-NSC were grafted into adult injured rats striatum and 3 days later, animals were killed, and brains were removed and examined by immunohistochemical analysis. RESULTS: The results showed that rhNGF-producing NSC cultured for extended period of time release bioactive hNGF in the culture media which promotes PC12 neuronal differentiation and correlates with the up-regulation of TrkA. rhNGF-NSC transplanted into the injured brain can survive, produce hNGF and induce the expression of NGF receptors, p75(NTR) and TrkA. DISCUSSION: In vitro and in vivo experiments confirmed the ability of rhNGF-NSC to secrete bioactive hNGF. Our data provide by means of genetically modified rhNGF-producing NSC, a useful experimental tool to test the potential clinical effectiveness of trophic factors relevant to central nervous system (CNS).

Nerve growth factor eye drop administrated on the ocular surface of rodents affects the nucleus basalis and septum: biochemical and structural evidence.

It has been shown that conjunctivally applied NGF in rats can reach the retina and optic nerve. Whether topical eye NGF application reaches the central nervous system is not known. In the present study, we have addressed this question. It was found that topical eye NGF application affects brain cells. Time-course studies revealed that repeated NGF application leads to high concentration of this neurotrophins after 6 h and normal levels after 24 h. Our results also showed that topical eye application of NGF causes an enhanced expression of NGF receptors and ChAT immunoreactivity in forebrain cholinergic neurons, suggesting that ocular NGF application could have a functional role on damaged brain cells. The present findings suggest that eye NGF application can represent an alternative route to prevent degeneration of NGF-receptive neurons involved in disorders such as Alzheimer and Parkinson.

Effects of electroacupuncture on retinal nerve growth factor and brain-derived neurotrophic factor expression in a rat model of retinitis pigmentosa.

The aim of this study was to investigate the effect of electroacupuncture (EA) on the progression of retinal degeneration in rats affected by inherited retinitis pigmentosa (IRP) and to correlate this event with the retinal expression of neurotrophins. Thirty-day-old Royal College of Surgeons (RCS) rats were exposed to 25-min-long daily sessions of low-frequency EA for 11 consecutive days. Control-untreated and EA-treated rats were sacrificed 1 h after the last EA session, and their retina removed for biochemical, molecular, and immunohistochemical analyses. Our data revealed that daily sessions of low-frequency EA for 11 days to RCS rats during a critical developmental stage of retinal cell degeneration cause an increase of retinal nerve growth factor (NGF) and NGF high-affinity receptor (TrkA) expression; and increase of outer nuclear layer (ONL) thickness; and enhanced vascularization. These findings suggest the possible beneficial effects of EA treatment in the development of IRP-like retinal degeneration of RCS rats and that the mechanism through which EA might exerts its action on the regulation of NGF and brain-derived neurotrophic factor (BDNF) and/or their receptors in retinal cells.