Týmus je primárny lymfatický orgán s dôležitou endokrinnou funkciou. Lokalizovaný je v hornom mediastíne, u novorodencov zasahuje do predného mediastína. Morfológia týmusu sa značne líši dokonca v rovnakej vekovej kategórii. U mladých jedincov je tvorený dvoma asymetrickými lalokmi a má tvar písmena „V“, pričom výbežky kraniálne siahajú do krčnej oblasti. Anomálie tvaru, veľkosti a lokalizácie týmusu možno vysvetliť narušením vývinu základu týmusu v hltanovej oblasti embrya a/alebo narušením jeho zostupu z oblasti krku do mediastína. Medzi najčastejšie anomálie týmusu zaraďujeme odchýlky v počte lalokov, ektopický týmus, prídavné tkanivo týmusu, apláziu týmusu, kombinovanú apláziu týmusu a prištítnych teliesok (DiGeorgeov syndróm), hypopláziu a hyperpláziu týmusu. V súčasnej literatúre je značná nejednota v klasifikácii anomálií týmusu, na ktoré v našom príspevku poukazujeme. Opierame sa pri tom o poznatky o vývine týmusu a postupujeme podľa odporúčania medzinárodnej Terminologia Embryologica. Cystická forma akcesórneho tkaniva týmusu lokalizovaného na krku sa označuje ako „vrodená krčná cysta týmusu“. Týmofaryngová krčná cysta je ďalší špeciálny a veľmi vzácny variant akcesórneho cystického tkaniva týmusu. Pomerne častá a asymptomatická anatomická variácia je fúzia týmusu s jedným alebo s viacerými prištítnymi telieskami.
Thymus is a central lymphoid organ with an important endocrine function located in the superior mediastinum, but in newborns it caudally reaches to anterior mediastinum. Thymic morphology varies greatly even in the same age group. For instance, in young adults, it is typically bilobed and V-shaped, with two small processes extending into the neck. Anomalies of the thymic shape, size and localization are explained by the disruption of thymic primordia formation and/or disruption of its descent from the neck to the mediastinum. The most common thymic anomalies include anomalies in number of the thymic lobes, ectopic thymus, accessory thymic tissue, thymic aplasia, thymoparathyroid aplasia (DiGeorge syndrome), thymic hypoplasia and hyperplasia. In a case of ectopic thymus, the whole thymus is (most often) located in the midline neck, and no thymic tissue is located in the normal position in the mediastinum. The presence of accessory thymic tissue reflects a failed migration of the whole thymic primordia from the third pharyngeal pouches. It may be found at any level of the pathway of normal thymic descent, from the angle of the mandible to the superior mediastinum. The prevalence of foci of accessory thymic tissue varies according to several authors from 1.8% up to more than 50%. A great controversy about the terms being used in the classification of thymic anomalies arises in current literature. Most of the recent articles use the term “ectopic thymus” in a confusing way, because they call cervical extension of the thymus, accessory cervical lobes of the thymus or accessory thymic tissue also “ectopic thymus”. The “genuine” ectopic thymus is a distinct entity from accessory thymic tissue localized in the neck. The term “ectopic thymus” should be reserved for states where only ectopic thymic tissue is present, while no thymus tissue is localized in the normal, mediastinal position. These two entities are differentiated also according to the recommendation of the Terminologia Embryologica (ectopia thymi versus textus thymicus accessorius). A cystic version of accessory thymic tissue localized in the neck is called “congenital cervical thymic cyst”. The cystic version of aberrant thymic tissue is more often described in the literature than the “classical” solid form. Thymopharyngeal duct cyst is another special and extremely rare variant of cystic accessory thymic tissue. Only circa 5 cases are described in the literature. Relatively common and asymptomatic anatomical variation is the fusion of thymus with one or more parathyroid glands - much common with the inferior due to common embryonic origin of both organs. Key-words: accessory thymic tissue, DiGeorge syndrome, ectopic thymus, embryonic development, human thymus, Terminologia Embryologica
- MeSH
- cysty mediastina * diagnóza klasifikace vrozené MeSH
- dítě MeSH
- hyperplazie thymu * diagnóza klasifikace vrozené MeSH
- klasifikace * MeSH
- lidé MeSH
- nádory brzlíku * diagnóza klasifikace vrozené MeSH
- thymus * abnormality anatomie a histologie růst a vývoj MeSH
- vrozené, dědičné a novorozenecké nemoci a abnormality MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Several deleterious effects may occur when intense and exhaustive exercise (IE) is not well-planned. This study aimed to investigate the effects of a short duration IE on body chemical composition and hypothalamic-pituitary-adrenal (HPA) axis. C57Bl/6 mice were distributed into four groups (10 mice per group): control (C-4D and C-10D), 4 days (E-4D), and 10 days of IE (E-10D). IE program consisted of a daily running session at 85 % of maximum speed until the animal reached exhaustion. Body weight as well as total body water, fat and protein content were determined from animal carcasses. HPA activation was assessed by plasma corticosterone levels measured by radioimmunoassay and the weight of both the adrenal glands and thymus were measured. Plasma corticosterone levels increased by 64 % in both the E-4D and E-10D groups. The weight of the adrenal glands augmented by 74 % and 45 %, at 4 and 10 days of IE, respectively, whereas thymus weight diminished by 15 % only in the E-10D group. The total carcass fat content decreased by 20 % only at 4 days IE, whereas protein content decreased by 20 % in both E-4D and E-10D groups. A relationship between corticosterone plasma levels and loss of body protein content in both E-4D and E-10D groups was observed (R(2)=0.999). We concluded that IE may be related to HPA axis activation associated with remodeling of body chemical composition in C57BL/6 mice.
- MeSH
- běh MeSH
- biologické markery krev MeSH
- časové faktory MeSH
- fyziologický stres * MeSH
- kortikosteron krev MeSH
- kosterní svaly anatomie a histologie metabolismus MeSH
- myši inbrední C57BL MeSH
- nadledviny anatomie a histologie metabolismus MeSH
- proteiny metabolismus MeSH
- proteolýza MeSH
- složení těla * MeSH
- svalová únava * MeSH
- systém hypofýza - nadledviny anatomie a histologie metabolismus MeSH
- systém hypotalamus-hypofýza metabolismus MeSH
- tělesná námaha * MeSH
- thymus anatomie a histologie MeSH
- velikost orgánu MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The thymus plays a critical role in establishing and maintaining the peripheral T-cell pool. It does so by providing a microenvironment within which T-cell precursors differentiate and undergo selection processes to create a functional population of major histocompatibility complex-restricted, self-tolerant T cells. These cells are central to adaptive immunity. Thymic T-cell development is influenced by locally produced soluble factors and cell-to-cell interactions, as well as by sympathetic noradrenergic and endocrine system signalling. Thymic lymphoid and non-lymphoid cells have been shown not only to express beta- and alpha(1)- adrenoceptors (ARs), but also to synthesize catecholamines (CAs). Thus, it is suggested that CAs influence T-cell development via both neurocrine/endocrine and autocrine/paracrine action, and that they serve as immunotransmitters between thymocytes and nerves. CAs acting at multiple sites along the thymocyte developmental route affect T-cell generation not only numerically, but also qualitatively. Thymic CA level and synthesis, as well as AR expression exhibit sex steroid-mediated sexual dimorphism. Moreover, the influence of CAs on T-cell development exhibits glucocorticoid-dependent plasticity. This review summarizes recent findings in this field and our current understanding of complex and multifaceted neuroendocrine-immune communications at thymic level.
- MeSH
- adrenergní receptory fyziologie imunologie MeSH
- experimenty na zvířatech MeSH
- financování organizované MeSH
- glukokortikoidy fyziologie imunologie MeSH
- homeostáza fyziologie imunologie MeSH
- katecholaminy fyziologie imunologie MeSH
- krysa rodu rattus MeSH
- metaanalýza jako téma MeSH
- pohlavní dimorfismus MeSH
- statistika jako téma MeSH
- T-lymfocyty cytologie fyziologie imunologie MeSH
- thymové hormony fyziologie izolace a purifikace metabolismus MeSH
- thymus anatomie a histologie enzymologie fyziologie MeSH
- Check Tag
- krysa rodu rattus MeSH
- Publikační typ
- přehledy MeSH
OBJECTIVE: To determine sonographically the transverse diameter of the fetal thymus and present nomogram for the transverse diameter of the fetal thymus in uncomplicated singleton pregnancies between 19 and 38 weeks of gestation. Setting: Department of Obstetrics and Gynecology, Charles University in Prague, Faculty of Medicine Hradec Kralove, University Hospital Hradec Kralove, Czech Republic. METHODS: A prospective study was performed. The transverse diameter of the fetal thymus was measured by the one experienced examiner in 198 healthy fetuses between 19 and 38 weeks of gestation. RESULTS: The transverse diameters of the fetal thymus were obtained from 183 of the 198 subjects. The regression equation was expressed as a function of gestational age: the transverse diameter of the fetal thymus (mm) = 1.001 × gestational age (week) - 0.932 or 0.143 × day - 1.34. Both the correlation coefficients, r=0.91 for weeks and r=0.92 for days were found to be highly statistically significant (p<0.0001). CONCLUSION: This study presents normative data (mean, 5th and 95th) for the ultrasound measurements of the transverse diameter of the fetal thymus in healthy singleton pregnancies.
- MeSH
- gestační stáří MeSH
- lidé MeSH
- nomogramy MeSH
- plod MeSH
- regresní analýza MeSH
- těhotenství MeSH
- thymus anatomie a histologie ultrasonografie MeSH
- ultrasonografie prenatální MeSH
- vývoj plodu MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
AIMS: Thymus is the central lymphatic organ in humans with important endocrine function that is involved in maturation of immunocompetent T-lymphocytes. In our study we investigated the relationship among thymus size and the anthropometric dimensions as well as between thymus size and the number of lymphocytes in peripheral blood in full-term newborns. METHODS: The examined group consisted of 212 full-term newborns from the region of Southern Slovakia. We examined birth weight, birth body length, head circumference and chest circumference. Thymus size was estimated by ultrasonography and it was expressed as Thymic Index. The number of lymphocytes in peripheral blood was determined from the number of total leukocytes and from the leukogram. RESULTS: We have found a statistically significant positive correlation among thymus size and the body dimensions of newborns. The highest correlation with thymus size was found for birth weight (r = 0.409; P < 0.001) followed by birth body length (r = 0.368; P < 0.001), head circumference (r = 0.365; P < 0.001) and chest circumference (r = 0.340; P < 0.001). We have proven also a statistically significant positive correlation between the number of lymphocytes in peripheral blood and thymus size (r = 0.208; P = 0.039). CONCLUSION: Our results confirmed the findings of other authors about a close relationship of Thymic Index and basic body parameters in newborns.
- MeSH
- antropometrie MeSH
- financování organizované MeSH
- lidé MeSH
- novorozenec krev MeSH
- počet lymfocytů MeSH
- thymus anatomie a histologie MeSH
- velikost orgánu MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec krev MeSH
- ženské pohlaví MeSH
- Geografické názvy
- Slovenská republika MeSH
