206 research outputs found

    C-Telopeptide Pyridinoline Cross-Links: Sensitive Indicators of Periodontal Tissue Destruction

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    C-telopeptides and related pyridinoline cross-links of bone Type I collagen are sensitive markers of bone resorption in osteolytic diseases such as osteoporosis and osteoarthritis. We have studied the release of C-telopeptide pyridinoline crosslinks of Type I collagen as measures of bone destruction in periodontal disease. Studies in preclinical animal models and humans have demonstrated the relationship between radiographic bone loss and crevicular fluid C-telopeptide levels. We have recently found that C-telopeptide levels correlate strongly with microbial pathogens associated with periodontitis and around endosseous dental implants. Host-modulation of bone-related collagen breakdown has been shown by studies in humans demonstrating that MMP inhibition blocks tissue destruction and release of C-telopeptides in patients with active periodontal disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72598/1/j.1749-6632.1999.tb07698.x.pd

    Helical distribution of the bacterial chemoreceptor via colocalization with the Sec protein translocation machinery

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    In Escherichia coli, chemoreceptor clustering at a cell pole seems critical for signal amplification and adaptation. However, little is known about the mechanism of localization itself. Here we examined whether the aspartate chemoreceptor (Tar) is inserted directly into the polar membrane by using its fusion to green fluorescent protein (GFP). After induction of Tar–GFP, fluorescent spots first appeared in lateral membrane regions, and later cell poles became predominantly fluorescent. Unexpectedly, Tar–GFP showed a helical arrangement in lateral regions, which was more apparent when a Tar–GFP derivative with two cysteine residues in the periplasmic domain was cross-linked to form higher oligomers. Moreover, similar distribution was observed even when the cytoplasmic domain of the double cysteine Tar–GFP mutant was replaced by that of the kinase EnvZ, which does not localize to a pole. Observation of GFP–SecE and a translocation-defective MalE–GFP mutant, as well as indirect immunofluorescence microscopy on SecG, suggested that the general protein translocation machinery (Sec) itself is arranged into a helical array, with which Tar is transiently associated. The Sec coil appeared distinct from the MreB coil, an actin-like cytoskeleton. These findings will shed new light on the mechanisms underlying spatial organization of membrane proteins in E. coli

    Electron Dynamics in Nd1.85_{1.85}Ce.15_{.15}CuO4+δ_{4+\delta}: Evidence for the Pseudogap State and Unconventional c-axis Response

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    Infrared reflectance measurements were made with light polarized along the a- and c-axis of both superconducting and antiferromagnetic phases of electron doped Nd1.85_{1.85}Ce.15_{.15}CuO4+δ_{4+\delta}. The results are compared to characteristic features of the electromagnetic response in hole doped cuprates. Within the CuO2_2 planes the frequency dependent scattering rate, 1/τ(ω)\tau(\omega), is depressed below \sim 650 cm1^{-1}; this behavior is a hallmark of the pseudogap state. While in several hole doped compounds the energy scales associated with the pseudogap and superconducting states are quite close, we are able to show that in Nd1.85_{1.85}Ce.15_{.15}CuO4+δ_{4+\delta} the two scales differ by more than one order of magnitude. Another feature of the in-plane charge response is a peak in the real part of the conductivity, σ1(ω)\sigma_1(\omega), at 50-110 cm1^{-1} which is in sharp contrast with the Drude-like response where σ1(ω)\sigma_1(\omega) is centered at ω=0\omega=0. This latter effect is similar to what is found in disordered hole doped cuprates and is discussed in the context of carrier localization. Examination of the c-axis conductivity gives evidence for an anomalously broad frequency range from which the interlayer superfluid is accumulated. Compelling evidence for the pseudogap state as well as other characteristics of the charge dynamics in Nd1.85_{1.85}Ce.15_{.15}CuO4+δ_{4+\delta} signal global similarities of the cuprate phase diagram with respect to electron and hole doping.Comment: Submitted to PR

    Surface-wave imaging of the weakly-extended Malawi Rift from ambient-noise and teleseismic Rayleigh waves from onshore and lake-bottom seismometers

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    Located at the southernmost sector of the Western Branch of the East African Rift System, the Malawi Rift exemplifies an active, magma-poor, weakly extended continental rift. To investigate the controls on rifting, we image crustal and uppermost mantle structure beneath the region using ambient-noise and teleseismic Rayleigh-wave phase velocities between 9 and 100 s period. Our study includes six lake-bottom seismometers located in Lake Malawi (Nyasa), the first time seismometers have been deployed in any of the African rift lakes. Noise-levels in the lake are lower than that of shallow oceanic environments and allow successful application of compliance corrections and instrument orientation determination. Resulting phase-velocity maps reveal slow velocities primarily confined to Lake Malawi at short periods (T 25 s) a prominent low-velocity anomaly exists beneath the Rungwe Volcanic Province at the northern terminus of the rift basin. Estimates of phase-velocity sensitivity indicates these low velocities occur within the lithospheric mantle and potentially uppermost asthenosphere, suggesting that mantle processes may control the association of volcanic centers and the localization of magmatism. Beneath the main portion of the Malawi Rift, a modest reduction in velocity is also observed at periods sensitive to the crust and upper mantle, but these velocities are much higher than those observed beneath Rungwe

    Hearing and vision rehabilitation for people with dementia in five European countries (SENSE-Cog): a randomised controlled trial

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    Background: The effect of hearing and vision difficulties on the risk of developing dementia and worsening outcomes in people already living with dementia is well established. We evaluated the clinical impact of a hearing and vision rehabilitation and support programme on quality of life in people with mild-to-moderate dementia and concurrent sensory difficulties. Methods: We conducted a parallel-group, multicentre, observer-blind, superiority randomised controlled trial in seven older adult clinics in five European countries (Cyprus, France, Greece, Ireland, and the UK). People with mild-to-moderate dementia with adult-acquired hearing difficulties, vision difficulties, or both were randomly assigned (1:1) along with their care partner to an 18-week home-based sensory support intervention (SSI) of tailored hearing and vision rehabilitation and support, or to care as usual. Randomisation was blocked (block size of four, six, or eight) and stratified by country, with allocation assigned via a remote web-based system. The SSI included: full hearing assessment, vision assessment, or both; fitting of hearing aids, glasses, or other sensory aids; and home-based support from a sensory support therapist to assist adherence and uptake of sensory aids, foster social networking, and optimise the home sensory environment. Care as usual involved no additional intervention beyond services normally available to people with dementia at the respective sites. The primary outcome was health-related quality of life (Dementia Quality of Life Instrument [DEMQoL]) score at 36 weeks, reported as an adjusted mean difference. Analyses were done according to the intention-to-treat principle. This trial is registered with the ISRCTN Registry, ISRCTN17056211. Findings: Between May 4, 2018, and May 6, 2021, 252 people with mild-to-moderate dementia were randomly assigned, of whom 251 (n=126 in the SSI group and n=125 in the care as usual group) were included in the analysis. The mean age of participants was 79·6 years (SD 5·8), and 132 (53%) were women. After a median follow-up time of 37·7 weeks (IQR 36·2–39·0), the mean DEMQoL score was 92·8 (SD 15·2) in the SSI group and 92·8 (14·0) in the care as usual group (adjusted difference 0·18, 95% CI –2·13 to 2·30, p=0·87). Among 114 adverse events reported for 56 (44%) participants in the SSI group, ten events in nine participants were related or possibly related to the intervention (medical device pain or discomfort n=6, ear pain n=1, scratch to the ear n=1, sore eye n=1, redness n=1; all of grade 1). Serious adverse events were reported for 25 (20%) participants in the SSI group and 16 (13%) in the care as usual group. Six (5%) participants in the SSI group and five (4%) in the care as usual group died. None of the serious adverse events or deaths were related to the study intervention or procedures. Interpretation: This study showed no improvement in quality in life in participants who received the intervention in the longer term. Sensory difficulties are common in people with dementia and interventions aimed at improving sensory-cognitive health should be explored further

    History of clinical transplantation

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    How transplantation came to be a clinical discipline can be pieced together by perusing two volumes of reminiscences collected by Paul I. Terasaki in 1991-1992 from many of the persons who were directly involved. One volume was devoted to the discovery of the major histocompatibility complex (MHC), with particular reference to the human leukocyte antigens (HLAs) that are widely used today for tissue matching.1 The other focused on milestones in the development of clinical transplantation.2 All the contributions described in both volumes can be traced back in one way or other to the demonstration in the mid-1940s by Peter Brian Medawar that the rejection of allografts is an immunological phenomenon.3,4 © 2008 Springer New York
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