151 research outputs found
Advanced carcinoma of the hypopharynx: functional results after circumferential pharyngolaryngectomy with flap reconstruction
Surgical treatment of advanced cancers of the hypopharynx inevitably impairs swallowing, respiration and phonation. The purpose of this study was to analyze the functional results after circumferential pharyngolaryngectomy (CPL) and flap reconstruction, in order to offer decisional guidelines for the choice of the most effective reconstructive method. We performed a retrospective analysis on the medical records of patients submitted to reconstructive surgery after CPL from July 1991 to November 2011. 75% of the 94 patients underwent reconstruction with a free flap (group A), while 25% underwent reconstruction with a pedicled flap (group B); 80% of patients in group A and none in group B were discharged with a free diet; 14% of patients in group A and 26% in group B were unable to resume oral feeding and were discharged with NG-tube or PEG. None of the patients acquired a satisfactory oesophageal voice; 17% of patients in group A and 7% in group B underwent voice restoration with tracheo-oesophageal voice-prosthesis. In conclusion, free flaps should be considered the first choice for reconstruction of the hypopharynx after CPL because of the better functional results obtained. Pedicled flaps represent a valid alternative in patients with contraindications to microvascular surgery
A comprehensive analysis of methods for assessing polygenic burden on Alzheimerâs disease pathology and risk beyond APOE
Genome-wide association studies have identified dozens of loci that alter the risk to develop Alzheimerâs disease. However, with the exception of the APOE-Δ4 allele, most variants bear only little individual effect and have, therefore, limited diagnostic and prognostic value. Polygenic risk scores aim to collate the disease risk distributed across the genome in a single score. Recent works have demonstrated that polygenic risk scores designed for Alzheimerâs disease are predictive of clinical diagnosis, pathology confirmed diagnosis and changes in imaging biomarkers. Methodological innovations in polygenic risk modelling include the polygenic hazard score, which derives effect estimates for individual single nucleotide polymorphisms from survival analysis, and methods that account for linkage disequilibrium between genomic loci. In this work, using data from the Alzheimerâs disease neuroimaging initiative, we compared different approaches to quantify polygenic disease burden for Alzheimerâs disease and their association (beyond the APOE locus) with a broad range of Alzheimerâs disease-related traits: cross-sectional CSF biomarker levels, cross-sectional cortical amyloid burden, clinical diagnosis, clinical progression, longitudinal loss of grey matter and longitudinal decline in cognitive function. We found that polygenic scores were associated beyond APOE with clinical diagnosis, CSF-tau levels and, to a minor degree, with progressive atrophy. However, for many other tested traits such as clinical disease progression, CSF amyloid, cognitive decline and cortical amyloid load, the additional effects of polygenic burden beyond APOE were of minor nature. Overall, polygenic risk scores and the polygenic hazard score performed equally and given the ease with which polygenic risk scores can be derived; they constitute the more practical choice in comparison with polygenic hazard scores. Furthermore, our results demonstrate that incomplete adjustment for the APOE locus, i.e. only adjusting for APOE-Δ4 carrier status, can lead to overestimated effects of polygenic scores due to APOE-Δ4 homozygous participants. Lastly, on many of the tested traits, the major driving factor remained the APOE locus, with the exception of quantitative CSF-tau and p-tau measures
Hippocampal subfield volumetry: differential pattern of atrophy in different forms of genetic frontotemporal dementia
BACKGROUND: Frontotemporal dementia (FTD) is a heterogeneous neurodegenerative disorder, with a strong genetic component. Previous research has shown that medial temporal lobe atrophy is a common feature of FTD. However, no study has so far investigated the differential vulnerability of the hippocampal subfields in FTD.
OBJECTIVES: We aimed to investigate hippocampal subfield volumes in genetic FTD.
METHODS: We in6/2/2018vestigated hippocampal subfield volumes in a cohort of 75 patients with genetic FTD (age: mean (standard deviation) 59.3 (7.7) years; disease duration: 5.1(3.4) years; 29 with MAPT, 28 with C9orf72, and 18 with GRN mutations) compared with 97 age-matched controls (age: 62.1 (11.1) years). We performed a segmentation of their volumetric T1-weighted MRI scans to extract hippocampal subfields volumes. Left and right volumes were summed and corrected for total intracranial volumes.
RESULTS: All three groups had smaller hippocampi than controls. The MAPT group had the most atrophic hippocampi, with the subfields showing the largest difference from controls being CA1-4 (24â27%, p < 0.0005). For C9orf72, the CA4, CA1, and dentate gyrus regions (8â11%, p < 0.0005), and for GRN the presubiculum and subiculum (10â14%, p < 0.0005) showed the largest differences from controls.
CONCLUSIONS: The hippocampus was affected in all mutation types but a different pattern of subfield involvement was found in the three genetic groups, consistent with differential cortical-subcortical network vulnerability
Total hip arthroplasty in an inveterate femoral neck fracture in a patient with congenital insensitivity to pain with anhidrosis
Congenital insensitivity to pain with anhidrosis (CIPA) is an extremely rare disorder characterized by autonomic and sensory nerves malfunction with insensitivity to both deep and superficial painful stimuli, inability to sweat and produce tears, and mild to moderate mental retardation with self-mutilating behavior. Related consequences of inveterate musculoskeletal injuries represent a major issue for these patients, since pain cannot act as a protectionmechanism. For the same reason, the patients are at risk during postoperative rehabilitation, which should be taken into account when selecting an orthopaedic implant. To our knowledge, only one case of total hip arthroplasty has been reported in the literature to date. A 21-year-old Caucasian male patient affected with CIPA arrived at our attention complaining about a functional limitation of the left hip. No history of trauma was reported. The X-rays showed an inveterate femoral neck fracture with a severe necrosis and resorption of the femoral head. We decided to performa total hip arthroplasty with a cemented stem and a cemented dual mobility cup. The postoperative course and rehabilitation were satisfactory, with excellent clinical results, measured with the Harris Hip Score at 1 year
The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST)
(abridged:) The XMM-Newton Extended Survey of the Taurus Molecular Cloud
(XEST) surveys the most populated ~5 square degrees of the Taurus star
formation region, using the XMM-Newton X-ray observatory to study the thermal
structure, variability, and long-term evolution of hot plasma, to investigate
the magnetic dynamo, and to search for new potential members of the
association. Many targets are also studied in the optical, and high-resolution
X-ray grating spectroscopy has been obtained for selected bright sources. The
X-ray spectra have been coherently analyzed with two different thermal models
(2-component thermal model, and a continuous emission measure distribution
model). We present overall correlations with fundamental stellar parameters
that were derived from the previous literature. A few detections from Chandra
observations have been added. The present overview paper introduces the project
and provides the basic results from the X-ray analysis of all sources detected
in the XEST survey.Comprehensive tables summarize the stellar properties of all
targets surveyed. The survey goes deeper than previous X-ray surveys of Taurus
by about an order of magnitude and for the first time systematically accesses
very faint and strongly absorbed TMC objects. We find a detection rate of 85%
and 98% for classical and weak-line T Tau stars (CTTS resp. WTTS), and identify
about half of the surveyed protostars and brown dwarfs. Overall, 136 out of 169
surveyed stellar systems are detected. We describe an X-ray luminosity vs. mass
correlation, discuss the distribution of X-ray-to-bolometric luminosity ratios,
and show evidence for lower X-ray luminosities in CTTS compared to WTTS.
Detailed analysis (e.g., variability, rotation-activity relations, influence of
accretion on X-rays) will be discussed in a series of accompanying papers.Comment: 75 pg, 77 figs. Accepted by A&A, to appear in a special section/issue
dedicated to the XMM-Newton Extended Survey of the Taurus Molecular Cloud
(XEST). V2: ASCII Table 14 added. Version with higher resolution figures at
http://www.issibern.ch/teams/Taurus/papers.html or
http://www.astro.phys.ethz.ch/papers/guedel/guedel_p_nf.htm
The stellar association around Gamma Velorum and its relationship with Vela OB2
We present the results of a photometric BVI survey of 0.9 square degrees
around the Wolf-Rayet binary gamma^2 Vel and its early-type companion gamma^1
Vel. Several hundred PMS stars are identified and the youth of a subset of
these is confirmed by the presence of lithium, H-alpha emission and X-ray
activity. We show that the PMS stars are kinematically coherent and spatially
concentrated around gamma Vel. The PMS stars have similar proper motions to
gamma Vel, to main-sequence stars around gammaVel and to early-type stars of
the wider Vela OB2 association of which gamma^2 Vel is the brightest member.
The ratio of main-sequence stars to low-mass (0.1-0.6 Msun) PMS stars is
consistent with a Kroupa mass function. Main-sequence fitting to stars around
gamma Vel gives a distance modulus of 7.76+/-0.07 mag, consistent with a
similarly-determined distance for Vela OB2 and with interferometric distances
to gamma^2 Vel. High-mass stellar models indicate an age of 3-4 Myr for gamma^2
Vel, but the low-mass PMS stars have ages of ~10 Myr according to low-mass
evolutionary models and 5-10 Myr by empirically placing them in an age sequence
with other clusters based on colour-magnitude diagrams and lithium depletion.
We conclude that the low-mass PMS stars form a genuine association with gamma
Vel and that this is a subcluster within the larger Vela OB2 association. We
speculate that gamma^2 Vel formed after the low-mass stars, expelling gas,
terminating star formation and unbinding the association. The velocity
dispersion of the PMS stars is too low for this star forming event to have
produced all the stars in Vela OB2. Instead, star formation must have started
at several sites within a molecular cloud, either sequentially or,
simultaneously after some triggering event [abridged].Comment: Accepted for publication in MNRA
KLâVS heterozygosity reduces brain amyloid in asymptomatic at-risk APOEâ4 carriers
KLOTHOâVS heterozygosity (KLâVSHET+) was recently shown to be associated with reduced risk of Alzheimer's disease (AD) in APOEâ4 carriers. Additional studies suggest that KLâVSHET+ protects against amyloid burden in cognitively normal older subjects, but sample sizes were too small to draw definitive conclusions. We performed a well-powered meta-analysis across 5 independent studies, comprising 3581 pre-clinical participants ages 60â80, to investigate whether KLâVSHET+ reduces the risk of having an amyloid-positive positron emission tomography scan. Analyses were stratified by APOEâ4 status. KLâVSHET+ reduced the risk of amyloid positivity in APOEâ4 carriers (odds ratio = 0.67 [0.52â0.88]; p = 3.5 Ă 10â3), but not in APOEâ4 non-carriers (odds ratio = 0.94 [0.73â1.21]; p = 0.63). The combination of APOEâ4 and KLâVS genotypes should help enrich AD clinical trials for pre-symptomatic subjects at increased risk of developing amyloid aggregation and AD. KL-related pathways may help elucidate protective mechanisms against amyloid accumulation and merit exploration for novel AD drug targets. Future investigation of the biological mechanisms by which KL interacts with APOEâ4 and AD are warranted
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