1,138 research outputs found

    The effects of the spontaneous presence of a spouse/partner and others on cardiovascular reactions to an acute psychological challenge

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    The presence of supportive others has been associated with attenuated cardiovascular reactivity in the laboratory. The effects of the presence of a spouse and others in a more naturalistic setting have received little attention. Blood pressure and heart rate reactions to mental stress were recorded at home in 1028 married/partnered individuals. For 112 participants, their spouse/partner was present; for 78, at least one other person was present. Women tested with a spouse/partner present showed lower magnitude systolic blood pressure and heart rate reactivity than those tested without. Individuals tested with at least one nonspousal other present also displayed attenuated reactivity. This extends the results of laboratory studies and indicates that the spontaneous presence of others is associated with a reduction in cardiovascular reactivity in an everyday environment; spouse/partner presence would appear to be especially effective for women.\ud \u

    Life events and hemodynamic stress reactivity in the middle-aged and elderly

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    Recent versions of the reactivity hypothesis, which consider it to be the product of stress exposure and exaggerated haemodynamic reactions to stress that confers cardiovascular disease risk, assume that reactivity is independent of the experience of stressful life events. This assumption was tested in two substantial cohorts, one middle-aged and one elderly. Participants had to indicate from a list of major stressful life events up to six they had experienced in the previous two years. They were also asked to rate how disruptive and stressful they were, at the time of occurrence and now. Blood pressure and pulse rate were measured at rest and in response to acute mental stress. Those who rated the events as highly disruptive at the time of exposure and currently exhibited blunted systolic blood pressure reactions to acute stress. The present results suggest that acute stress reactivity may not be independent of stressful life events experience

    Quantification of very low-abundant proteins in bacteria using the HaloTag and epi-fluorescence microscopy.

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    Cell biology is increasingly dependent on quantitative methods resulting in the need for microscopic labelling technologies that are highly sensitive and specific. Whilst the use of fluorescent proteins has led to major advances, they also suffer from their relatively low brightness and photo-stability, making the detection of very low abundance proteins using fluorescent protein-based methods challenging. Here, we characterize the use of the self-labelling protein tag called HaloTag, in conjunction with an organic fluorescent dye, to label and accurately count endogenous proteins present in very low numbers (<7) in individual Escherichia coli cells. This procedure can be used to detect single molecules in fixed cells with conventional epifluorescence illumination and a standard microscope. We show that the detection efficiency of proteins labelled with the HaloTag is ≄80%, which is on par or better than previous techniques. Therefore, this method offers a simple and attractive alternative to current procedures to detect low abundance molecules

    Impaired Notch Signaling Promotes \u3cem\u3eDe novo\u3c/em\u3e Squamous Cell Carcinoma Formation

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    Signaling through Notch receptors in the skin has been implicated in the differentiation, proliferation, and survival of keratinocytes, as well as in the pathogenesis of basal cell carcinoma (BCC). To determine the composite function of Notch receptor–mediated signaling in the skin and overcome potential redundancies between receptors, conditional transgenic mice were generated that express the pan-Notch inhibitor, dominant-negative Mastermind Like 1 (DNMAML1), to repress all canonical [CBF-1/Suppressor of hairless/LAG-1 (CSL)–dependent] Notch signaling exclusively in the epidermis. Here, we report that DNMAML1 mice display hyperplastic epidermis and spontaneously develop cutaneous squamous cell carcinoma (SCC) as well as dysplastic precursor lesions, actinic keratoses. Mice expressing epidermal DNMAML1 display enhanced accumulation of nuclear ß-catenin and cyclin D1 in suprabasilar keratinocytes and in lesional cells from SCCs, which was also observed in human cutaneous SCC. These results suggest a model wherein CSL-dependent Notch signaling confers protection against cutaneous SCC. The demonstration that inhibition of canonical Notch signaling in mice leads to spontaneous formation of SCC and recapitulates the disease in humans yields fundamental insights into the pathogenesis of SCC and provides a unique in vivo animal model to examine the pathobiology of cutaneous SCC and for evaluating novel therapies

    New Insights into the Lactate Shuttle: Role of MCT4 in the Modulation of the Exercise Capacity.

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    Lactate produced by muscle during high-intensity activity is an important end product of glycolysis that supports whole body metabolism. The lactate shuttle model suggested that lactate produced by glycolytic muscle fibers is utilized by oxidative fibers. MCT4 is a proton coupled monocarboxylate transporter preferentially expressed in glycolytic muscle fibers and facilitates the lactate efflux. Here we investigated the exercise capacity of mice with disrupted lactate shuttle due to global deletion of MCT4 (MCT4−/−) or muscle-specific deletion of the accessory protein Basigin (iMSBsg−/−). Although MCT4−/− and iMSBsg−/− mice have normal muscle morphology and contractility, only MCT4−/− mice exhibit an exercise intolerant phenotype. In vivo measurements of compound muscle action potentials showed a decrement in the evoked response in the MCT4−/− mice. This was accompanied by a significant structural degeneration of the neuromuscular junctions (NMJs). We propose that disruption of the lactate shuttle impacts motor function and destabilizes the motor unit
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