622 research outputs found
Pregnancy follow-up in a patient with mechanical valve: possible in sub-Saharan Africa?
Background: In Africa in general and in Cameroon in particular, post rheumatic cardiopathies are a health care problem, one of the causes of infertility in the women population and a major cause of death among children and adults. Management of a pregnant woman with mechanical heart valve is a complex issue for all health care providers involved in the care of such patients. Patient and case report: Miss A is 26-years old and consulted for cardiac assessment; referred from Bamenda (North-West province of Cameroon) for better management of a cardiac problem including arrhythmia and a history of recurrent tonsillitis. The cardiac echo-dopplerography showed severe post-rheumatic mitral valve regurgitation with pulmonary hypertension and a dysfunctional left ventricle. The patient was later evacuated in a surgical centre in Milan San Donato (Italy) where a St. Jude mechanical heart valve N.27 was implanted. Two years after surgery, during a follow-up visit, the patient brought a pelvic ultrasound showing a single live intrauterine foetus, gestational age estimated at 7 weeks. Conclusion: anagement of mechanical valve in a pregnancy context, resulting in a favourable outcome (no thromboembolic events and the delivery of a healthy baby) is possible in sub-
Saharan Africa. Close observation, adherence to existing clinical guidelines, patient cooperation and an appropriate technical infrastructure are critical factors to consider
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Laguerre–Gauss and Hermite–Gauss soft X-ray states generated using diffractive optics
Light’s capacity to carry angular momentum is integral to our knowledge of physics and ability to probe matter. In addition to spin, photons can occupy free-space orbital angular momentum eigenstates 1,2 . Visible light orbital angular momentum is used in quantum information experiments, super-resolution microscopy, optical tweezers and angular momentum transfer to atoms in optical lattices 3,4 . Soft X-ray orbital angular momentum applications, slowed by the lack of suitable optics and the rarity of coherent X-ray sources, could enable the direct alteration of atomic states through orbital angular momentum exchange, and methods to study the electronic properties of quantum materials. We have made soft X-ray diffractive optics that generate single Laguerre–Gauss modes, observed carrying up to 30ħ angular momentum per photon, or their superpositions. We also present Hermite–Gauss diffractive optics and a soft X-ray orbital angular momentum analyser. These tools could enable both the manipulation and finer characterization of topologically complex electronic matter, such as magnetic skyrmions
Polymorphisms of CR1, CLU and PICALM confer susceptibility of Alzheimer's disease in a southern Chinese population
In this case-controlled study, we tested susceptible genetic variants for Alzheimer's disease (AD) in CR1, CLU and PICALM from genome-wide association studies (GWAS) in a southern Chinese population. Eight hundred twelve participants consisting of 462 late-onset Alzheimer's disease (LOAD) patients and 350 nondemented control subjects were recruited. We found by multivariate logistic regression analysis, that single nucleotide polymorphisms (SNPs) in CR1 (rs6656401 adjusted allelic p = 0.035; adjusted genotypic p = 0.043) and CLU (rs2279590 adjusted allelic p = 0.035; adjusted genotypic p = 0.006; rs11136000 adjusted allelic p = 0.038; adjusted genotypic p = 0.009) were significantly different between LOAD patients and nondemented controls. For PICALM, LOAD association was found only in the APOE ε4 (-) subgroup (rs3851179 adjusted allelic p = 0.028; adjusted genotypic p = 0.013). Our findings showed evidence of CR1, CLU, and PICALM and LOAD susceptibility in an independent southern Chinese population, which provides additional evidence for LOAD association apart from prior genome-wide association studies in Caucasian populations. © 2012 Elsevier Inc.postprin
Chromosome 4q;10q translocations; Comparison with different ethnic populations and FSHD patients
BACKGROUND: Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disorder characterized by the weakness of facial, shoulder-girdle and upper arm muscles. Most patients with FSHD have fewer numbers of tandem repeated 3.3-kb KpnI units on chromosome 4q35. Chromosome 10q26 contains highly homologous KpnI repeats, and inter-chromosomal translocation has been reported. METHODS: To clarify the influence on the deletion of the repeats, we surveyed three different ethnic populations and FSHD patients using the BglII/BlnI dosage test. RESULTS: The frequency of translocation in 153 Japanese, 124 Korean, 114 Chinese healthy individuals and 56 Japanese 4q35-FSHD patients were 27.5%, 29.8%, 19.3%, and 32.1%, respectively. The ratio of '4 on 10' (trisomy and quatrosomy of chromosome 4) was higher than that of '10 on 4' (nullsomy and monosomy of chromosome 4) in all populations. CONCLUSIONS: The inter-chromosomal exchange was frequently observed in all four populations we examined, and no significant difference was observed between healthy and diseased groups
ISSLS PRIZE in Clinical Science 2023: comparison of degenerative MRI features of the intervertebral disc between those with and without chronic low back pain. An exploratory study of two large female populations using automated annotation
Objectives
The relationship of degeneration to symptoms has been questioned. MRI detects apparently similar disc degeneration and degenerative changes in subjects both with and without back pain. We aimed to overcome these problems by re-annotating MRIs from asymptomatic and symptomatics groups onto the same grading system.
Methods
We analysed disc degeneration in pre-existing large MRI datasets. Their MRIs were all originally annotated on different scales. We re-annotated all MRIs independent of their initial grading system, using a verified, rapid automated MRI annotation system (SpineNet) which reported degeneration on the Pfirrmann (1–5) scale, and other degenerative features (herniation, endplate defects, marrow signs, spinal stenosis) as binary present/absent. We compared prevalence of degenerative features between symptomatics and asymptomatics.
Results
Pfirrmann degeneration grades in relation to age and spinal level were very similar for the two independent groups of symptomatics over all ages and spinal levels. Severe degenerative changes were significantly more prevalent in discs of symptomatics than asymptomatics in the caudal but not the rostral lumbar discs in subjects
Conclusions
We confirmed age and disc level are significant in determining imaging differences between asymptomatic and symptomatic populations and should not be ignored. Automated analysis, by rapidly combining and comparing data from existing groups with MRIs and information on LBP, provides a way in which epidemiological and ‘big data’ analysis could be advanced without the expense of collecting new groups.
Level of evidence I
Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding
A predicted physicochemically distinct sub-proteome associated with the intracellular organelle of the anammox bacterium Kuenenia stuttgartiensis
Medema MH, Zhou M, van Hijum SAFT, et al. A predicted physicochemically distinct sub-proteome associated with the intracellular organelle of the anammox bacterium Kuenenia stuttgartiensis. BMC Genomics. 2010;11(1): 299.Background Anaerobic ammonium-oxidizing (anammox) bacteria perform a key step in global nitrogen cycling. These bacteria make use of an organelle to oxidize ammonia anaerobically to nitrogen (N2) and so contribute ~50% of the nitrogen in the atmosphere. It is currently unknown which proteins constitute the organellar proteome and how anammox bacteria are able to specifically target organellar and cell-envelope proteins to their correct final destinations. Experimental approaches are complicated by the absence of pure cultures and genetic accessibility. However, the genome of the anammox bacterium Candidatus "Kuenenia stuttgartiensis" has recently been sequenced. Here, we make use of these genome data to predict the organellar sub-proteome and address the molecular basis of protein sorting in anammox bacteria. Results Two training sets representing organellar (30 proteins) and cell envelope (59 proteins) proteins were constructed based on previous experimental evidence and comparative genomics. Random forest (RF) classifiers trained on these two sets could differentiate between organellar and cell envelope proteins with ~89% accuracy using 400 features consisting of frequencies of two adjacent amino acid combinations. A physicochemically distinct organellar sub-proteome containing 562 proteins was predicted with the best RF classifier. This set included almost all catabolic and respiratory factors encoded in the genome. Apparently, the cytoplasmic membrane performs no catabolic functions. We predict that the Tat-translocation system is located exclusively in the organellar membrane, whereas the Sec-translocation system is located on both the organellar and cytoplasmic membranes. Canonical signal peptides were predicted and validated experimentally, but a specific (N- or C-terminal) signal that could be used for protein targeting to the organelle remained elusive. Conclusions A physicochemically distinct organellar sub-proteome was predicted from the genome of the anammox bacterium K. stuttgartiensis. This result provides strong in silico support for the existing experimental evidence for the existence of an organelle in this bacterium, and is an important step forward in unravelling a geochemically relevant case of cytoplasmic differentiation in bacteria. The predicted dual location of the Sec-translocation system and the apparent absence of a specific N- or C-terminal signal in the organellar proteins suggests that additional chaperones may be necessary that act on an as-yet unknown property of the targeted proteins
Skyrmion fluctuations at a first-order phase transition boundary
Magnetic skyrmions are topologically protected spin textures with promising prospects for applications in data storage. They can form a lattice state due to competing magnetic interactions and are commonly found in a small region of the temperature - magnetic field phase diagram. Recent work has demonstrated that these magnetic quasi-particles fluctuate at the μeV energy scale. Here, we use a coherent x-ray correlation method at an x-ray free-electron laser to investigate these fluctuations in a magnetic phase coexistence region near a first-order transition boundary where fluctuations are not expected to play a major role. Surprisingly, we find that the relaxation of the intermediate scattering function at this transition differs significantly compared to that deep in the skyrmion lattice phase. The observation of a compressed exponential behavior suggests solid-like dynamics, often associated with jamming. We assign this behavior to disorder and the phase coexistence observed in a narrow field-window near the transition, which can cause fluctuations that lead to glassy behavior
GRANULOMA CENTRAL DE CÉLULAS GIGANTES
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