Neurološki simptomi nedostatka vitamina B12: analiza pedijatrijskih bolesnika

Vitamin B12 is one of the essential vitamins that affect various systems in the body, including the central nervous system. Vitamin B12 plays an important part in the metabolism of the nervous system, although its exact role under pathological conditions is not fully understood. The purpose of this study was to emphasize the importance of early diagnosis of vitamin B12 deficiency in the light of the characteristics of the patients enrolled. This retrospective, clinical study included 38 children with neurological symptoms of vitamin B12 deficiency. Records of 38 patients referred to a single center of the university hospital outpatient child neurology clinic due to neurological symptoms of vitamin B12 deficiency between February 2012 and December 2013 were evaluated retrospectively. Patients aged 0-18 years with symptoms including syncope, dizziness, convulsion, hypotonia, developmental retardation, tremor, ataxia, tingling sensations and paresthesia, blurring of vision, fatigue and concentration difficulty caused by vitamin B12 deficiency were included in the study. Patient neurological findings included syncope (n=6), dizziness (n=4), hypotonia (n=9), inability to sit or walk without support, or gait ataxia (n=2), convulsion (n=4), hand tremor (n=1), tingling sensations and paresthesia (n=3), vision blurring (n=1), fatigue and concentration difficulty (n=8). All patients with neurological symptoms of vitamin B12 deficiency recovered within one month after vitamin B12 supplementation. In conclusion, clinical characteristics of vitamin B12 deficiency are broad and nonspecific and may not be associated with anemia and increased mean corpuscular volume. Since different clinical characteristics can be seen without anemia, awareness and cautious approach are essential in order to avoid severe clinical disease, especially in children from underdeveloped countries.Vitamin B12 jedan je od ključnih vitamina koji utječe na razne sustave u organizmu uključujući središnji živčani sustav. Vitamin B12 ima važnu ulogu u metabolizmu živčanog sustava, iako njegova uloga u patološkim stanjima nije u potpunosti razjašnjena. Namjera ovoga istraživanja bila je naglasiti važnost rane dijagnoze nedostatka vitamina B12 u svjetlu karakteristika bolesnika uključenih u istraživanje. Ovo retrospektivno kliničko istraživanje uključilo je 38 djece s neurološkim simptomima nedostatka vitamina B12. Retrospektivno su analizirani podaci za 38 djece upućene u ambulantu za dječju neurologiju jedne sveučilišne bolnice zbog neuroloških simptoma nedostatka vitamina B12 između veljače 2012. i prosinca 2013. godine. Uključeni su bolesnici u dobi od 0 do 18 godina sa sljedećim simptomima uzrokovanim nedostatkom vitamina B12: sinkopa, vrtoglavica, konvulzije, hipotonija, zastoj u razvoju, tremor, ataksija, trnci i parestezije, zamagljen vid, umor i otežana koncentracija. U bolesnika su zabilježeni sljedeći neurološki nalazi: sinkopa (n=6), vrtoglavica (n=4), hipotonija (n=9), nemogućnost da sjedi ili hoda bez potpore, ili ataksija u hodu (n=2), konvulzije (n=4), tremor ruku (n=1), trnci i parestezija (n=3), zamagljen vid (n=1), umor i otežana koncentracija (n=8). Svi bolesnici s neurološkim simptomima nedostatka vitamina B12 oporavili su se kroz jedan mjesec nakon nadomještanja vitamina B12. U zaključku, kliničke značajke nedostatka vitamina B12 široke su i nespecifične te ne moraju biti udružene s anemijom i povećanim srednjim korpuskularnim volumenom. Kako se razne kliničke značajke mogu zapaziti bez anemije, svijest o ovom nedostatku i pažljiv pristup bitni su kako bi se izbjegla teška klinička bolest, poglavito u djece iz manje razvijenih zemalja

An optimal stopping problem for spectrally negative Markov additive processes

Previous authors have considered optimal stopping problems driven by the running maximum of a spectrally negative L\'evy process $X$, as well as of a one-dimensional diffusion. Many of the aforementioned results are either implicitly or explicitly dependent on Peskir's maximality principle. In this article, we are interested in understanding how some of the main ideas from these previous works can be brought into the setting of problems driven by the maximum of a class of Markov additive processes (more precisely Markov modulated L\'evy processes). Similarly to previous works in the L\'evy setting, the optimal stopping boundary is characterised by a system of ordinary first-order differential equations, one for each state of the modulating component of the Markov additive process. Moreover, whereas scale functions played an important role in the previously mentioned work, we work instead with scale matrices for Markov additive processes here. We exemplify our calculations in the setting of the Shepp-Shiryaev optimal stopping problem, as well as a family of capped maximum optimal stopping problems.Comment: 31 page

Deformable MRI fusion for intracranial SRS: Can we trust?

Purpose/Objective: The aim of this study is to evaluate the reliability of MRI fusion for the determination of target volume when performing CT based intracranial stereotactic radiosurgery. Materials and Methods: Patients treated with CT based intracranial stereotactic radiosurgery with various diagnoses are included in the study. All patients were immobilized using stereotactic thermoplastic masks prior to simulation. The planning CT was obtained both with and without iv contrast with 1mm slice thickness

Socio-economic tools to mitigate the impacts of ocean acidification on economies and communities reliant on coral reefs — a framework for prioritization

Coral reef preservation is a challenge for the whole of humanity, not just for the estimated three billion people that directly depend upon coral reefs for their livelihoods and food security. Ocean acidification combined with rising sea surface temperatures, and an array of other anthropogenic influences such as pollution, sedimentation, over fishing, and coral mining represent the key threats currently facing coral reef survival. Here we summarize a list of agreements, policies, and socio-economic tools and instruments that can be used by global, national and local decision-makers to address ocean acidification and associated threats, as identified during an expert workshop in October 2017. We then discuss these tools and instruments at a global level and identify the key tasks for raising decision makers’ awareness. Finally, we suggest ways of prioritizing between different actions or tools for mitigation and adaptation

Dosimetric comparison of linac-based modulated techniques for hippocampal sparing whole brain radiotherapy

Objective Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques were compared in terms of their dosimetric quality, treatment efficiency, and delivery accuracy for hippocampal sparing prophylactic whole brain radiotherapy. Methods Ten previously treated patients were selected for this study. All plans were prescribed to deliver 30 Gy in 10 fractions to 90% of the target volume. RTOG 0933 recommendations were applied for treatment planning. Plans were compared based on the organ at risk (OAR) sparing, homogeneity and conformity indexes, monitor unit (MU), and beam on time (BOT). Delivery accuracy of the plans was also compared. Results VMAT plans had better homogeneity index and conformity index than IMRT plans. In terms of hippocampus sparing, VMAT plans were superior to other plans. Since brainstem, optic nerves, and chiasm were in the PTV, their doses were nearly equal to each other for both techniques. So, there were no statistical differences between techniques. Although both eyes were not in the PTV, there was no significant dose difference between techniques. However, due to the posterior gantry angles of IMRT plans, lens doses were lower in IMRT plans than those in VMAT plans. The VMAT technique had lower MU and BOT values than the IMRT technique. In terms of delivery accuracy, VMAT plans were superior than IMRT plans. Conclusion VMAT plans provide better target volume coverage, homogeneity, conformity, and hippocampus sparing when compared with IMRT plans. VMAT plans are also the best in terms of treatment efficiency since they require a much smaller number of MUs and thus a shorter treatment time than IMRT plans

Distribution of maximum loss of fractional Brownian motion with drift

In this paper, we find bounds on the distribution of the maximum loss of fractional Brownian motion with H >= 1/2 and derive estimates on its tail probability. Asymptotically, the tail of the distribution of maximum loss over [0, t] behaves like the tail of the marginal distribution at time t