23 research outputs found
A madár thymus dendritikus sejtjeinek in vivo identifikálása és a thymus velőállományának kompartmentalizációja
Avian coronavirus infection induces mannose-binding lectin production in dendritic cell precursors of chicken lymphoid organs
The aim of this immunocytochemical study was to compare mannose-binding lectin (MBL) production induced by avian coronavirus in the spleen and caecal tonsil (CT). One-day-old specific-pathogen-free (SPF) chickens were experimentally infected with six QX field isolates and the H120 vaccine strain. In the negative control birds, the spleen was MBL negative, while the CT showed scattered MBL-positive cells in close proximity and within the surface epithelium and germinal centre (GC)-like cell clusters. MBL was detectable in the ellipsoid-associated cells (EACs) and cell clusters in the periarterial lymphoid sheath (PALS) by 7 days post infection (dpi). In both organs, the MBL-positive cells occupy antigen-exposed areas, indicating that GC formation depends on resident precursors of dendritic cells. The majority of MBL-positive EACs express the CD83 antigen, providing evidence that coronavirus infection facilitated the maturation of dendritic cell precursors. Surprisingly, co-localisation of MBL and CD83 was not detectable in the CT. In the spleen (associated with circulation), the EACs producing MBL and expressing CD83 are a common precursor of both follicular (FDC) and interdigitating dendritic cells (IDC). In the CT (gut-associated lymphoid tissue, GALT) the precursors of FDC and IDC are MBL-producing cells and CD83-positive cells, respectively. In the CT the two separate precursors of lymphoid dendritic cells provide some ‘autonomy’ for the GALT
A thymus szerkezete a huszonegyedik század elején = Structure of the thymus at the beginning of the 21th century
Absztrakt:
A thymus klasszikus hisztológiai tulajdonságai: a kéreg- és velőállomány, a
Hassall-testek és a mirigyekre jellemző lebenyezettség. Az anti-páncitokeratin
festése azt mutatja, hogy a kérgi és velőhámsejtek keratinmintázata különböző. A
velőállomány további kompartmentekre különül: keratinpozitív hálózatra és
keratinnegatív területre. A keratinpozitív hálózat összeköttetésben áll a kérgi
hámreticulummal, míg a keratinnegatív terület folyamatos a septumok kötőszöveti
állományával. A keratinnegatív területnek, a toknak és a septumnak a
támasztószövete reticularis kötőszövet. A kéregállományt a tok és a septumok
reticularis kötőszövetétől folyamatos bazális membrán választja el, de a
keratinnegatív területek és a keratinpozitív hálózat határánál a bazális membrán
szakadozottá válik. Ez az immunhisztokémiai lelet az első, amely magyarázhatja,
hogy miért nincs a velőállományában vér-thymus barrier. A keratinnegatív terület
és a septumok támasztószövetének azonossága azt sugallja, hogy a sövények és a
keratinnegatív területek azonos eredetűek. A thymus tokja és sövényei a
cranialis ganglionlécből származnak, ezért feltételezzük, hogy a keratinnegatív
terület is ganglionléc-eredetű. A velőállomány vérerei a keratinnegatív
területben helyezkednek el, ezért minden, a thymusból kilépő vagy abba belépő,
immunológiailag kompetens sejtnek keresztül kell mennie a keratinnegatív
területen. Ez azt sugallja, hogy a keratinnegatív terület a thymus
tranzitzónája. A hematoxilin-eozin festés alapján megjelenő kéreg-velő határt
nem reprezentálja sejtes háttér, de a keratinpozitív hálózat és a keratinnegatív
terület között húzódó határt sejtes összetétele határozza meg
(epithelium-mesenchyma). Feltételezzük, hogy a keratinnegatív terület és a
keratinpozitív hálózat között lévő határ a thymus valódi szövettani és
funkcionális határa. Orv Hetil. 2019; 160(5): 163–171.
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Abstract:
The classical histological features of the thymus are the cortex and medulla, the
Hassall’s bodies as well as the lobules. Anti-pan-cytokeratin
immunocytochemistry shows that the keratin staining pattern of the cortical and
medullary epithelial cells is different. The medulla is further
compartmentalized: it consists of keratin-positive network and keratin-negative
areas. Histology of the keratin-negative area is identical with the connective
tissue of the septae. The basal lamina is continuous at the capsule and septae,
but it becomes discontinuous at the border between the keratin-positive network
and keratin-negative area. This immunohistochemical finding is the first
histological sign, which may explain that the medulla has no blood-thymus
barrier. The supporting tissue of the keratin-negative area is identical with
that of the septae. The connective tissue of thymic capsule and septae develops
from the cranial neural crest cells, therefore we hypothesize that the
keratin-negative area has neural crest origin. Blood vessels of the thymic
medulla localize in the keratin-negative area. Every emigrating or immigrating
immunologically competent cells should enter the keratin-negative area,
therefore this area is the transit zone of the thymus. The hematoxylin-eosin
staining of the thymus shows that the thymic cortico-medullary border does not
represent cellular background. However, the border between keratin-positive
network and keratin-negative area is determined by cellular identity (epithelial
and mesenchymal tissues). Therefore, it can be assumed that the real
histological and functional border is the border between the keratin-positive
network and the keratin-negative area. Orv Hetil. 2019; 160(5): 163–171
Nehéz helyzetben a HEART Team: valve-in-valve implantáció? = HEART Team in trouble: valve-in-valve implantation?
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Wall motion changes in myocardial infarction in relation to the time elapsed from symptoms until revascularization
A szív pozitív inotróp támogatása a miozin-aktivátor hatású omecamtiv mecarbil segítségével = Inotropic therapy with the myosin activator omecamtiv mecarbil
Coronavirus infection retards the development of the cortico-medullary capillary network in the bursa of Fabricius of chicken
Coronavirus infection delays the development of the cortico-medullary (CM) capillary network which results in retarded development of bursal follicles. The smaller size of the medulla in the coronavirus-infected birds may lead to a lower number of B lymphocytes and bursal secretory dendritic cells, which negatively affects the reactivity and efficacy of the immune system. Contrary to the wild-type infectious bronchitis virus (IBV) strain, infection induced by H120 vaccine virus exerts only a moderate influence on caveolin-1 expression of the CM capillary web and on follicular development compared to the untreated controls
Az interventrikuláris szeptum mérése echokardiográfiával: mérési különbségek és klinikai következményeik
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A novel aspect of the structure of the avian thymic medulla.
We provide evidence for the compartmentalization of the avian thymic medulla and identify the avian thymic dendritic cell. The thymic anlage develops from an epithelial cord of the branchial endoderm. Branches of the cord are separated by primary septae of neural crest origin. The dilation of the primary septae produces the keratin-negative area (KNA) of the thymic medulla and fills the gaps of the keratin-positive network (KPN). Morphometric analysis indicates that the KNA takes up about half of the volume of the thymic medulla, which has reticular connective tissue, like peripheral lymphoid organs. The KNA receives blood vessels and in addition to pericytes, the myoid cells of striated muscle structure occupy this area. The myoid cells are of branchial arch or prechordal plate origin providing indirect evidence for the neural crest origin of the KNA. The marginal epithelial cells of the KPN co-express keratin and vimentin intermediate filaments, which indicate their functional peculiarity. The basal lamina of the primary septum is discontinuous on the surface of the KPN providing histological evidence for the loss of the blood-thymus barrier in the medulla. In the center of the KNA, the dendritic cells lie in close association with blood vessels, whereas the B-cells accumulate along the KPN. The organization of the KPN and KNA increases the "surface" of the so-called cortico-medullary border, thereby contributing to the efficacy of central tolerance