1,720,976 research outputs found
Brain and Spinal Cavernomas : Helsinki Experience
No full textCavernomas are rare neurovascular lesions, encountered in up to 10% of patients harboring vascular abnormalities of the CNS. Cavernomas consist of dilated thin-walled sinusoids or caverns covered by a single layer of endothelium.
Due to advancements in neuroradiology, the number of cavernoma patients coming to be evaluated in neurosurgical practice is increasing. In the present work, we summarized our results on the treatment of cavernomas. Particular attention was paid to uncommon locations or insufficiently investigated cavernomas, including 1. Intraventricular cavernomas; 2. Multiple cavernomas; 3. Spinal cavernomas; and 4. Temporal lobe cavernomas. After analyzing the patient series with these lesions, we concluded that:
1. IVCs are characterized by a high tendency to cause repetitive hemorrhages in a short period of time after the first event. In most patients, hemorrhages were not life-threatening. Surgery is indicated when re-bleedings are frequent and the mass-effect causes progressive neurological deterioration. Modern microsurgical techniques allow safe removal of the IVC, but surgery on fourth ventricle cavernomas carries increased risk of postoperative cranial nerve deficits.
2. In MC cases, when the cavernoma bleeds or generates drug-resistant epilepsy, microsurgical removal of the symptomatic lesion is beneficial to patients. In our series, surgical removal of the most active cavernoma usually the biggest lesion with signs of recent hemorrhage - was safe and prevented further bleedings. Epilepsy outcome showed the effectiveness of active treatment of MCs. However, due to the remaining cavernomas, epileptogenic activity can persist postoperatively, frequently necessitating long-term use of antiepileptic drugs.
3. Spinal cavernomas can cause severe neurological deterioration due to low tolerance of the spinal cord to mass-effect with progressive myelopathy. When aggravated by extralesional massive hemorrhage, neurological decline is usually acute and requires immediate treatment. Microsurgical removal of a cavernoma is effective and safe, improving neurological deficits. Sensorimotor deficits and pain improved postoperatively at a high rate, whereas bladder dysfunction remained essentially unchanged, causing social discomfort to patients.
4. Microsurgical removal of temporal lobe cavernomas is beneficial for patents suffering from drug-resistant epilepsy. In our series, 69% of patients with this condition became seizure-free postoperatively. Duration of epilepsy did not correlate with seizure prognosis. The most frequent disabling symptom at follow-up was memory disorder, considered to be the result of a complex interplay between chronic epilepsy and possible damage to the temporal lobe during surgery.Kavernoomien osuuden kaikista aivosuonten epämuodostumista arvioidaan olevan 5-10%. Pään magneettitutkimuksen tultua kliiniseen käyttöön on diagnosoitujen kavernoomien lukumäärä jatkuvasti lisääntynyt. Noin puolessa tapauksista kavernoomia pidetään synnynnäisinä. Kavernoomien histologiset piirteet on perusteellisesti tutkittu. Tavalliset taudin oireet ovat epilepsia tai neuroloogiset puutokset, mutta se voi aiheuttaa aivojensisäistä verenvuotoa, joka äärimmillään johtaa kuolemaan. Vuotuisen vuotoriskin arvioidaan olevan 0,3 5 % sijainnista riippuen.
Ainoana radikaalina kavernoomien hoitomuotona pidetään nykyään mikrokirurgista poistoa. Muista neurokirurgiassa käytettävistä hoitomenetelmistä ei ole varmistettu selvää tulosta.
Tähän tutkimukseen rekisteröity kaikki kavernomatapaukset Töölön sairaalasta ja Meilahden sairaalasta ajalta 1.01.1980 31.12.2009. Suurin osa Töölössä hoidetuista potilaista on saanut leikkaushoitoa.
Tässä tutkimuksessa erityistä huomiota kiinnitettiin harvinaisiin kavernoomiin: 1. Aivokammioiden sisällä sijaitsevat kavernoomat ; 2. Multippeli kavernoomat ; 3. Selkäkanavan kavernoomat; 4. Ohimolohkon kavernoomat . Tutkittuaan potilaiden sarjoja voimme päätellä, että:
1. Aivokammioiden sisällä sijaitsevilla kavernoomilla on suuri taipumus aiheuttaa toistuvia aivoverenvuotoja, vaikka useimmiten nämä vuodot eivät ole hengenuhkaavia. Kavernooman poisto on aiheellinen silloin, kun aivoverenvuodot toistuu useasti tai itse kavernooma johtaa neuroloogisiin puutoksiin. Nykyisellä mikroneurokirurgisella hoidolla aivokammion kavernoomia saadaan turvallisesti poistettua.
2. Verenvuodot ja vaikea-hoitoinen epilepsia liittyy tyypillisesti multippeli kavernoomiin. Meidän sarjassa, isoimman ja vuotaneen kavernooman mikrokirurginen poisto oli tehokas sekä verenvuodon ehkäisemisessä että epilepsian hoitamisessa. Kuitenkin jäljellä olevat kavernoomat kantavat mahdollisen riskin aiheuttaa epileptisiä kohtauksia, minkä takia epilepsialääkityksen pitkäkestoinen käyttö on suosi-teltu.
3. Selkäkanavan kavernoomat voivat johtaa vakaviin neuroloogisin puutoksiin. Äkillinen halvaus tai kipu raajoissa voi olla merkki kavernoomavuodosta, jolloin leikkaus on suoritettava päivystyksenä. Selkäkanavan kavernoomien mikrokirurginen poisto on tehokas ja turvallinen. Leikkauksen jälkeen, halvaus ja kipu paranevat hyvin, mutta virtsarakon toimintahäiriö pysyy pääosin ennallaan.
4. Ohimolohkon kavernoomilla on taipumusta aiheuttaa vaikea-hoitoista epilepsiaa. Niiden mikrokirurginen poisto parantaa potilaita kohtauksettomiksi noin 70 prosentissa. Yleisin leikkauksen jälkiseuraus oli muistivaikeuksia, minkä syy voi olla pitkäkestoinen epilepsia tai toimenpiteen aiheuttama vaurio.ei saavutettav
Complex networks approach to study comorbidities in patients with unruptured intracranial aneurysms
Full text linkthe role of complex network analysis in patients with diagnosis of unruptured intracranial aneurysm is unexplored. The objective of this study is to assess the applicability of this methodology in aneurysm patients. We retrospectively analyze comprehensive unbiased local digital data of a large number of patients treated for any reason between January 2004 and July 2019. We apply an age-cohort approach to a total of 628,831 patients and construct the diagnostic history of each patient-and include the information how old the patient was when diagnosed for the first time with each diagnosis coded according to International Classification of Diseases. For each cohort of age within a 10 year interval and for each gender, we construct a statistically validated comorbidity network and focused on crucial comorbidity links that the aneurysm code has to other disease codes within the whole network. For all cohorts of different age and gender, the analysis shows that 267 diagnose codes have nearest neighbour statistically validated links to unruptured aneurysm ICD code. Among the 267 comorbidities, 204 (76%) were found in patients aged from 40 to 69-years old. Patterns of connectivity with aneurysms were found for smoking, hypertension, chronic obstructive pulmonary disease, dyslipidemia, and mood disorders. A few uncommon connections are also detected in cohorts of female patients. Our study explored the applicability of network analysis and statistical validation in aneurysm observational study
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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