Ochorenia myelínu CNS sa súhrnne označujú ako leukoencefalopatie. Termín zahŕňa poruchy, pri ktorých zmeny v bielej hmote prevažujú alebo sú výlučné, pričom patofyziologický mechanizmus ani histopatologická báza nie sú rozhodujúce. Z tejto širokej skupiny vrodených a získaných porúch sa vyčleňuje skupina leukodystrofií, ktorá označuje primárnu poruchu myelínu a buniek tvoriacich myelín. Klasicky sa do tejto skupiny radí šesť klinických jednotiek: X‑adrenoleukodystrofia, metachromatická leukodystrofia, Krabbeho globoidná leukodystrofia, Canavanovej choroba, Pelizaeus‑Merzbacherova choroba a Alexandrova choroba. Pribúdajúcimi poznatkami sa skupina rozširuje o stále nové primárne poruchy. Pre presnú diagnostiku je dôležitý klinický nález, významné sú zmeny na MR mozgu a laboratórne vyšetrenia. Precíznou analýzou MR obrazu je možné diagnostický proces urýchliť. Jedným zo spoločných znakov leukodystrofií je progresívny priebeh. U detí nastáva zväčša rýchla strata motorických a kognitívnych funkcií. V prípade adolescentov a adultných pacientov je ťažisko zmien v psychickej a mentálnej oblasti, pričom motorický deficit nastupuje neskôr. Priebeh X‑adrenoleukodystrofie, metachromatickej leukodystrofie, Krabbeho globoidnej leukodystrofie sa dá vo včasnom štádiu alebo predklinickom období ovplyvniť transplantáciou kostnej drene alebo kmeňových buniek. V prípade metachromatickej leukodystrofie je v skorých štádiách indikovaná génová a enzýmová terapia. Pre ostatné leukodystrofie je dostupná len symptomatická liečba. Cieľom práce je zhrnutie najdôležitejších poznatkov a liečebných možností., Myelin disorders of the central nervous system are also known as leukoencephalopathies. This term includes diseases, in which changes of the white matter are dominant, or even exclusive, while neither the pathophysiological mechanism nor the histopathological basis are decisive. This broad selection of inborn and acquired disorders includes a group of leukodystrophies characterized by primary dysfunction of myelin and myelin-producing cells. Typically, six separate clinical entities are included in this group: X-linked adrenoleukodystrophy, metachromatic leukodystrophy, Krabbe’s globoid cell leukodystrophy, Canavan disease, Pelizaeus-Merzbacher disease and Alexander disease. The group is constantly expanding as our knowledge develops. Clinical and laboratory findings, as well as MRI scans, are crucial for exact diagnosis. Accurate analysis of MRI images accelerates the diagnostic process considerably. A common feature of leukodystrophies is their progressive nature. Children exhibit rapid loss of motor and cognitive functions. In adolescent and adult patients, psychological and mental changes are the most prominent, while motor deficit has a later onset. The course of X-linked adrenoleukodystrophy, metachromatic leukodystrophy, and Krabbe’s leukodystrophy can be managed at the early or pre-clinical stages with bone marrow or stem cell transplantation. Gene and enzyme therapy are indicated at the earliest stages of metachromatic leukodystrophy. For the remaining leukodystrophies, only symptomatic therapy is available. The purpose of this paper is to summarize current information and knowledge as well as possible therapeutic options in this group of disorders., Vědomostní test, and M. Kolníková, P. Sýkora
Climate features that influence life cycles, notably severity, seasonality, unpredictability and variability, are summarized for different polar zones. The zones differ widely in these factors and how they are combined. For example, seasonality is markedly reduced by oceanic influences in the Subantarctic. Information about the life cycles of Arctic and Antarctic arthropods is reviewed to assess the relative contributions of flexibility and programming to life cycles in polar regions. A wide range of life cycles occurs in polar arthropods and, when whole life cycles are considered, fixed or programmed elements are well represented, in contrast to some recent opinions that emphasize the prevalence of flexible or opportunistic responses. Programmed responses ale especially common for controlling the appearance of stages that are sensitive to adverse conditions, such as the reproductive adult. The relative contribution of flexibility and programming to different life cycles is correlated with taxonomic affinity (which establishes the general lifecycle framework for a species), and with climatic zone, the habitats of immature and adult stages, and food., Hugh V. Danks, and Lit