Browsing by Subject "Thymus"

Now showing 1 - 18 of 18
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    Apoptosis of thymocytes in experimental African Swine Fever virus infection
    (Murcia : F. Hernández, 2004) Salguero, F.J.; Sánchez-Cordón, P.J.; Sierra, M. A.; Jover, A.; Núñez, A.; Gómez-Villamandos, J. C.
    This paper report on the lesions occurred in the thymus in experimental acute African swine fever (ASF). Twenty-one pigs were inoculated with the highly virulent ASF virus (ASFV) isolate Spain-70. Animals were slaughtered from 1 to 7 days post infection (dpi). Three animals with similar features were used as controls. Thymus samples were fixed in 10% buffered formalin solution for histological and immunohistochemical study and in 2.5% glutaraldehyde for ultrastructural examination. For immunohistochemical study, the avidin-biotin-peroxidase complex (ABC) technique was used to demonstrate viral protein 73 and porcine myeloid-histiocyte antigen SWC3 using specific monoclonal antibodies. Cell apoptosis was evaluated by the TUNEL assay. Blood samples were taken daily from all pigs and were used for leukocyte counts. The results of this study show a severe thymocyte apoptosis not related to the direct action of ASFV on these cells, but probably to a quantitative increase in macrophages in the thymus and their activation. A decrease in the percentage of blood lymphocytes was observed at the same time No significant vascular changes were observed in the study. With these results we suggest that ASFV infection of the thymus does not seem to play a critical role in the acute disease. Although severe apoptosis was observed, animals died because of the severe lesions found in the other organs.
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    Cocaine abuse and its impact on the thymus and spleen
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Aki, Toshihiko; Unuma, Kana; Biología Celular e Histología
    Cocaine is a psychostimulant abused worldwide. Its pharmacotoxicological properties are derived mainly from its impact on the neurotransmission of sympathomimetic nerves. Cocaine enhances and prolongs the neurotransmission of monoamines, such as dopamine, serotonin, and adrenaline, which are responsible not only for cocaine’s euphoric effects, but also its cardiovascular toxicity. In addition to these effects on central as well as peripheral nerves, immunosuppression is also implicated in cocaine toxicity. The thymus and spleen are lymphoid organs that are essential in lymphocyte maturation and erythrocyte homeostasis. Reductions in thymus and spleen size, which are observed under both physiological and pathological conditions, are known as thymic involution and splenic contraction, respectively. These phenomena are also observed in experimental animal models of binge cocaine abuse. In this brief review, we describe the mechanisms of cocaine toxicity, thymic involution, and splenic contraction, followed by discussions about the possible role of the latter two phenomena in cocaine intoxication.
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    Corticosterone 21-acetate in vivo induces acute stress in chicken thymus: cell proliferation, apoptosis and cytokine responses
    (Murcia : F. Hernández, 2004) Franchini, A.; Marchesini, E.; Ottaviani, E.
    In vivo effects of acute stress induced by corticosterone 21-acetate in male Gallus domesticus thymus are studied and the steroid actions are evaluated in terms of cell proliferation, apoptosis and cytokine response in 10- and 21-day-old chickens. Steroid treatment induced thymocyte apoptosis and cell death decreased in the cortical-medullar direction and was more evident in younger animals. 24 h after treatment, the observed effect was reversed. The mitotic activity and thymic cells containing cytokine-like molecules were also affected. Indeed, the acute stress stimulated cytokine immunoreactivity to anti-IL-1a, IL-6 and TNF- a antibodies both in epithelial cells and interdigitating cells located in medullar and cortical-medullar regions. The increased cytokine expression observed after 12 h was maintained after 24 h. The comparison between 10- and 21-day-old chickens showed a lower number of cells containing cytokine-like molecules in younger specimens. The present findings suggest that cytokines activated by acute stress in vivo could contribute to restoring immunological homeostasis and influence thymic glucocorticoid-mediated functions.
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    Cyclosporin A-induced changes of the thymic microenvironment. A review of morphological studies
    (Murcia : F. Hernández, 1998) Milicevic, N.M.; Milicevic, Z.
    Cyclosporin A is an immunosuppressive drug, which disrupts the activation of peripheral Tlymphocyte pool and blocks the maturation of thymocytes within the thymus. Normally, thymic nonlymphoid cells provide the optimal inductive microenvironment for development of T-lymphocytes. After application of cyclosporin A the complex alterations of the thymic microenvironment occur, affecting all types of nonlymphoid cells. All subsets of thymic epithelial cells are thoroughly changed. The subcapsular epithelial cells show the proGinent enlargement of cytokeratin contents. In electron microscopy, however, these cells present the morpho-functional aspect of resting cells. The epithelial cells in deeper cortex become enlarged and stockier, whereby their cell processes appear more ramified and thicker. Thus, the cytoreticulum they create seems much denser. These cells strongly express MHC antigens. Their subcellular organization is suggestive of increased synthetic and secretory activity. The number of medullary epithelial cells is decreased. The cells with the most mature phenotype are the most prominently depleted and the ones with phenotypically and morphologically immature appearance predominate.The number of Hassall's bodies is also decreased. The number of cortical macrophages does not increase. However, these cells become enlarged showing the prominent changes in enzyme capacity, histochemical features and ultrastructural organization. Thus, they become similar to macrophages located in the cortico-medullary zone of the normal rat thymus. Cortical macrophages increase the activity of hydrolytic enzymes, acid phosphatase and nonspecific esterase, develop the strong activity of chloroacetate esterase, the strong activity of respiratory enzyme succinic dehydrogenase and begin to show the marked presence of prostaglandin synthase. Moreover, the cytoplasmic inclusions, which are aldehyde fuchsin- and PASpositive and show sudanophilia, appear within cortical macrophages. In electron microscopy these cells show Offprint requests to: Prof. Dr. Novica Milcevk, Dim. Tucovka 83, 11000 Beograd. Yugoslavia an abundant cytoplasm a very active appearance and the variety of vacuolar cytoplasmic inclusions. The mitoses of neighboring thymocytes are often seen. The number of interdigitating cells is decreased due to reduced size of thymic medulla, but these cells do not show the substantial phenotypic changes. The description and classification of all types of nonlymphoid cells, which constitute the normal thymic microenvironment, is also presented. The functional significance and possible mechanisms of CSA-induced changes of the thymic microenvironment are discussed.
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    Effect of boric acid supplementation of ostrich water on the expression of Foxn1 in thymus
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2015) Xiao, Ke; Rahman Ansari, Abdur; ur Rehman, Zia; Khaliq, Haseeb; Song, Hui; Tang, Juan; Wang, Jing; Wang, Wei; Sun, Peng-Peng; Zhong, Juming; Peng, Ke-Mei
    Foxn1 is essential for thymus development. The relationship between boric acid and thymus development, optimal dose of boric acid in ostrich diets, and the effects of boric acid on the expression of Foxn1 were investigated in the present study. Thirty healthy ostriches were randomly divided into six groups: Group I, II, III, IV, V, VI, and supplemented with boric acid at the concentration of 0 mg/L, 40 mg/L, 80 mg/L, 160 mg/L, 320 mg/L, 640 mg/L, respectively. The histological changes in thymus were observed by HE staining, and the expression of Foxn1 analyzed by immunohistochemistry and western blot. TUNEL method was used to label the apoptotic cells. Ostrich Foxn1 was sequenced by Race method. The results were as following: Apoptosis in ostrich thymus was closely related with boric acid concentrations. Low boric acid concentration inhibited apoptosis in thymus, but high boric acid concentration promoted apoptosis. Foxn1- positive cells were mainly distributed in thymic medulla and rarely in cortex. Foxn1 is closely related to thymus growth and development. The nucleotide sequence and the encoded protein of Foxn1 were 2736 bases and 654 amino acids in length. It is highly conserved as compared with other species. These results demonstrated that the appropriate boric acid supplementation in water would produce positive effects on the growth development of ostrich thymus by promoting Foxn1 expression, especially at 80mg/L, and the microstructure of the thymus of ostrich fed 80 mg/L boric acid was well developed. The supplementation of high dose boron (>320mg/L) damaged the microstructure of thymus and inhibited the immune function by inhibiting Foxn1 expression, particularly at 640mg/L. The optimal dose of boric acid supplementation in ostrich diets is 80 mg/L boric acid. The genomic full-length of African ostrich Foxn1 was cloned for the first time in the study.
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    Endothelin-l enhances thymocyte proliferation in monolaterally adrenalectomized rats with contralateral adrenocortical regeneration
    (Murcia : F. Hernández, 1998) Malendowicz, L.K.; Macchi, Verónica; Brelinska, R.; Trejer, M.; Gottardo, Giuseppe; Nussdorfer, G.G.
    Endothelins (ETs) are a family of vasoactive peptides widely distributed in the body systems, where they exert pleiotropic biological effects, acting through two main subtypes of receptors, named ETA and ETB. Evidence indicates that ET-1 plays a permissive role in the development of neural crest-derived structures, among which are the epithelia1 cells of the thymus. These cells are known to control proliferation and differentiation of thymocytes, a process requiring adequate levels of glucocorticoids. Therefore, we have investigated the effects of ET-1, that binds both ETA and ETB receptors, on thymocyte proliferation in monolaterally adrenalectomized rats with contralateral enucleated adrenal at day 4 and 8 of regeneration, when glucocorticoid production is very low and, respectively, rather normal. Metaphase index (percentage of metaphase arrested cells) of thymocytes is the lowest at day 4 of regeneration, and markedly rose at day 8, thereby confirming the need of sizable levels of circulating glucocorticoid for the maintenance of a normal rate of thymocyte proliferation. ET-l markedly increased the mitotic index of thymocytes at both times of adrenal regeneration. At day 8 of regeneration, the ETA-receptor antagonist BQ-123 markedly lowered mitotic index of thymocytes, and annulled its ET-1- evoked raise. Conversely, the ETB-receptor antagonist BQ-788 was ineffective. Collectively, these findings clearly indicate that endogenous ETs, through the activation of ETA receptors, are involved in the maintenance and stimulation of thymocyte proliferation in the adult rat, thereby playing a possibly important role in the modulation of the immune-system functions.
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    Ethanol enhances thymocyte apoptosis and autophagy in macrophages of rat thymi
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2017) Betsuyaku, Tsubasa; Eid, Nabil; Ito, Yuko; Tanaka, Yoshihisa; Otsuki, Yoshinori; Kondo, Yoichi
    Tingible body macrophages (TBMs) play essential roles in the phagocytosis of apoptotic lymphocytes, specifically under exposure to various stressors. Although excessive ethanol consumption may enhance thymocyte apoptosis, reports investigating the autophagic response of the thymus to ethanol toxicity are still lacking. We investigated apoptosis and autophagy in thymi of an animal model of binge ethanol exposure. Adult male Wistar rats were injected intraperitoneally either with 5 g/kg ethanol or phosphate buffer saline (for the control group) and sacrificed 0, 3, 6 and 24 hours after injection. Light and transmission electron microscopy (TEM) studies revealed enhanced formation of TBMs phagocytosing many apoptotic thymocytes in the thymic cortex of the ethanol-treated rats (ETRs), and this formation was particularly marked at 24 h. The macrophages showed signs of activation under TEM and immunofluorescence double labeling with RM4 (a macrophage marker) and iNOS. Additionally, in comparison to the control group, autophagy was enhanced in ETR thymic TBMs as evidenced ultrastructurally by accumulation of autophagic vacuoles, immunohistochemical increases in LC3 puncta, Western blot analysis of the latter protein, and colocalization of LC3 and RM4 in immunofluorescence double labeling. Immunoelectron microscopy also revealed LC3-labeled autophagic vacuoles and apoptotic cell phagosomes in ETR TBMs, suggesting the possibility of LC3-related phagocytosis. This was confirmed by enhanced colocalization of LC3 with lysosomal cathepsins in double labeling. These results indicate that enhanced autophagy in ETR thymic TBMs is not only a cytoprotective mechanism but could also be involved in the clearance of apoptotic thymocytes, thus preventing autoimmune reactions and suppressing inflammatory response.
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    IIThe glycoconjugate sugar residues of the sessile and motile cells in the thymus of normal and Cyclosporin-A-treated rats: lectin histochemistry
    (Murcia : F. Hernández, 2002) Gheri, G.; Gheri Bryk, S.; Riccardi-Arbi, R.; Sgambati, E.; Cirri Borghi, M.B.
    It is well known that cell surface glycoconjugates play a determinant role in cellular recognition, cell-to-cell adhesion and serve as receptor molecules. T-lymphocytes are in strict contact with the thymic epithelial cells, which control their process of maturation and proliferation. On the other hand the normal maturation of the epithelial cells is believed to be induced by T-lymphocytes. For these reasons we have studied the glycoconjugates saccharidic moieties of the sessile and motile cells in the thymus of normal male albino Wistar rats and their changes following cyclosporin-A treatment, using a battery of seven HRPlectins. Cytochemical controls were performed for specificity of lectin-sugar reaction. Some sections were pre-treated with neuraminidase prior to staining with HRP-lectins. Our results have demonstrated, in the control rats, a large amount and a variety of terminal and subterminal oligosaccharides within and/or on the epithelial thymic cells and in macrophages. After cyclosporin-A treatment, among the thymic epithelial cells, the subcapsular, paraseptal and perivascular cells showed the loss of some sugar residues, which characterized the same cells in the intact thymus. Some hypotheses are reported on the role played by the glycoconjugate sugar residues in control and cyclosporin-A treated rats.
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    Linfomas primarios del timo
    (Elsevier, 2006-07) Ríos, A.; Torres, J.; Roca, M.J.; Galindo, P.J.; Alonso-Romero, José Luis; Parrilla, P.; Medicina
    Introducción. Los linfomas primarios tímicos (LPT) son infrecuentes, pero su pronóstico va ligado a un tratamiento precoz. Se realiza una revisión de esta patología en nuestro hospital con el objetivo de determinar cuál es el mejor manejo diagnóstico-terapéutico en estos pacientes. Material y métodos. Se revisan diez LPT, cuatro Hodgkin y seis no Hodgkin (4 linfomas primarios mediastínicos B [LPMB] y 2 linfomas linfoblásticos T [LLT]). La edad media fue de 23 ± 10 años, siendo la mayoría mujeres. Resultados. En los linfomas de Hodgkin la sospecha diagnóstica inicial fue de timoma en dos casos y de linfoma en los dos restantes. Todos fueron intervenidos, realizándose una biopsia intraoperatoria, completándose con una timectomía en los dos que informó de timoma. Se trataron con radioquimioterapia. En dos casos la respuesta fue parcial, completándose el tratamiento con un trasplante de médula ósea (TMO) (uno fue éxitus, y el otro presenta enfermedad activa). Los linfomas no Hodgkin (LNH) presentaban grandes tumoraciones y una evolución corta. Todos fueron intervenidos, realizándose en cuatro una biopsia y en dos una timectomía. Se trataron con quimioterapia, asociándose en dos radioterapia. La respuesta fue total en tres, recidivando dos, que tras TMO están en remisión completa. En los tres restantes la respuesta fue parcial. Conclusiones. Ante un paciente con tumoración tímica sugestiva por el estudio preoperatorio o intraoperatorio de linfoma debe realizarse una biopsia quirúrgica y no cirugía resectiva para evitar resecciones y morbilidad quirúrgica innecesaria. Los LPT son infrecuentes pero agresivos, sobre todo los LNH, siendo su principal tratamiento la radioquimioterapia, asociada a TMO en casos seleccionados.
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    Morphometrical changes in the rat thymic lymphoid cells after treatment with two different doses of estradiol benzoate
    (Murcia : F. Hernández, 1994) Martin, A.; Alonso, L.M.; Gomez del Moral, M.; Zapata, A.G.
    In the present study we have evaluated morphometrically the contribution of thymocytes to the thymic involution induced by a single injection either of 100 pg or 500 pg of estradiol benzoate. Our results demonstrate that changes in the numbers of both cortical and medullary thymocytes contribute to thymic involution although the importance of the first is quantitatively higher. On the other hand, while cortical pyknosis and a decreased mitotic index could be important for explaining the estrogen-dependent thymic changes, the release of lymphocytes from thymus seems to be the main factor inducing the thymic involution as well as the lack of recovery observed at the end of the experimental period.
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    Neonatal thymulin gene therapy in nude mice: Effects on the morphology of the pituitary corticotrope population
    (Murcia: F. Hernández, 2011) Martines, Eliana; Reggiani, Paula; Schwerdt, José I.; Goya, Rodolfo; Cónsole, Gloria
    The integrity of the thymus during early life is necessary for a proper maturation of the neuroendocrine system, including the adrenal axis. The thymic metallopeptide thymulin seems to be a central physiologic mediator of thymus-pituitary communication. Furthermore, neonatal thymulin gene therapy has been shown to prevent the typical alterations of gonadotrophic cell number and morphology and serum gonadotropin levels in nude female mice. In the present study we assessed the impact of athymia and the effect of neonatal thymulin gene therapy on the corticotropic cell population in nude mice. The effect of thymulin administration to adult nudes on their hypothalamic content of corticotropin-releasing hormone (CRH) and the adrenal content of corticosterone was also determined. We used an adenoviral vector expressing a synthetic gene for the thymic peptide thymulin (metFTS) termed RAd-FTS. On postnatal day 1 or 2, heterozygous (nu/+) and homozygous (nu/nu) pups of both sexes received a single bilateral i.m. injection of RAd-FTS or RAd-GFP, a control vector. On postnatal day 71, mice were bled and sacrificed, and their pituitaries were immediately dissected, fixed and immunostained for corticotropin. Morphometry was performed by means of an image-analysis system. The following parameters were calculated: volume density (VD: Σ cell area/reference area), cell density (CD: number of cells/reference area), and cell surface (CS: expressed in µm2). Serum thymulin levels were measured by a bioassay, and CRH as well as corticosterone were determined by IRMA and RIA, respectively. Neonatal thymulin gene therapy in the athymic mice restored their serum thymulin levels and increased corticotrope CD, VD and CS in both control and athymic mice. Athymic mice showed only a marginal reduction in corticotrope CD, VD and CS. In these mutants hypothalamic CRH content was slightly increased, whereas adrenal corticosterone tended to be lower. Thymulin administration to adult mice tended to reverse these changes. Our results suggest a possible modulating effect of thymulin on the corticotrope population and the adrenal gland, confirming the existence of a bidirectional thymus-pituitary-adrenal axis.
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    Neoplasias primarias del timo de estirpe no linfoide. Estudio de 58 casos
    (Elsevier, 2004) Ríos Zambudio, Antonio; Torres Lanzas, Juan; Galindo Fernández, Pedro José; Roca Calvo, María José; Alonso-Romero, José Luis; Sola Pérez, Joaquín; Parrilla Paricio, Pascual; Medicina
    Fundamento y objetivo: Los tumores primarios del timo de estirpe no linfoide son infrecuentes, aunque presentan una gran variedad. El objetivo de este trabajo es identificar las variables clínicas, terapéuticas e histológicas que tienen valor pronóstico. Pacientes y método: Se estudiaron 58 tumores primarios del timo de estirpe no linfoide que correspondieron a 52 neoplasias epiteliales (NEPT) (90%), 4 timolipomas (7%) y 2 tumores neuroendocrinos(3%). La clínica más frecuente fue la miastenia grave (41%) y la disnea (21%).Cabe destacar la presencia de 13 pacientes asintomáticos (24%). Para el análisis estadístico se utilizaron las curvas de supervivencia de Kaplan-Meier y el modelo de regresión de Cox. Resultados: Se intervino a todos los pacientes con timectomía, excepto en 4 casos en que se efectuó una biopsia. La mortalidad perioperatoria fue del 3% (n = 2) y la morbilidad, del 31%(n = 18), principalmente por afecciones respiratorias y de la herida. Se administró tratamiento adyuvante con quimioterapia y/o radioterapia en las 24 NEPT grados de Masaoka III y IV, y en el carcinoma linfoepitelial. Con un seguimiento medio (DE) de 13 (5) años, fallecieron 12 pacientes con NEPT y 1 con un tumor neuroendocrino, debido a evolución de la enfermedad. La supervivencia acumulada fue del 80% a los 5 años, del 71% a los 7 años y del 63% a los 10años. Actualmente existen 2 recidivas locales en 2 NEPT, tras 9 y 8 años de seguimiento, respectivamente. Los principales factores pronósticos son el tipo y subtipo histológicos, así como el estadio clínico (p < 0,001). Conclusiones: El diagnóstico precoz en los tumores primarios del timo de estirpe no linfoide es fundamental para instaurar un tratamiento correcto antes de que presenten un estadio clínico más avanzado. Los principales factores pronósticos son el tipo y subtipo histológicos, así como el estadio clínico.
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    Studies on the involvement Histology and Histopathology Cellular and Molecular Biology of endogenous neuropeptides in the control of thymocyte proliferation in the rat
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2001) Trejter, M.; Warchol, J. B.; de Caro, R.; Brelinska, R.; Nussdorfer, G. G.; Malendowicz, L. K.
    The possible involvement of endogenous vasoactive intestinal peptide (VIP), cholecystokinin (CCK) and neurotensin (NT) in the control of thymocyte proliferation ha s been investigated in vivo in the immature rat. For this task, we have studied the effects of the administration of selective antagonists of the receptors of the three neuropeptides on the mitotic index (%0 of metaphase-arrested cells after vincristin injection) of thymocytes. Both CCK- and TN-receptor antagonists were ineffective. In contrast, two VIP receptor antago nists (VIP-As) enhanced the mitotic index of thymocytes. VIP reversed the effect of VIP-As, but when administered alone it did not alter the mitotic activity of thymocytes. In light of these findings, we conclude that endogenous VIP exerts a maximal tonic inhibitory influence on the basal proliferative activity of rat thymocytes, while endogenous CCK and NT do not play a relevant modulatory role in thi process.
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    The effect of thymic inoculation to induce tolerance of allogeneic thyroid grafts in the outbred rabbit
    (Murcia : F. Hernández, 1998) Torchia, M.G.; Aitken, R.M.; Thliveris, A.
    Many studies have demonstrated that allograft tolerance can be achieved in inbred rats and mice following intrathymic injection of donor cells or antigen and treatment with antilymphocyte serum (ALS). In outbred dogs, xenografts, and inbred rat strains with major MHC antigen difference, tolerance has not similarly been induced. The focus of this study was to determine whether allogeneic thyroid graft tolerance could be achieved in outbred rabbits. In the experimental group (n=5), recipients received an intrathymic injection of donor lymphocytes and a single treatment of ALS. Controls (n=5) received intrathymic cell culture medium and ALS treatment. Donor-recipient allogenicity was monitored with mixed lymphocyte culture (MLC) over 18 weeks. Donor thyroid tissue was placed into recipient gluteal muscle fibres one week following the last MLC measurement. A third group of rabbits (n=4) received thyroid autografts without any other treatment. There were no differences in MLC stimulation indices (SI) between the control and experimental group nor did MLC (SI) change within groups. All thyroid autografts survived the two week monitoring period and demonstrated normal appearing thyroid follicles on histologic examination. All thyroid allografts showed severe acute rejection reactions on biopsy within one week. Further studies using outbred animals to examine the role of thymic inoculation are required to determine whether similar techniques might be successful in the human.
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    The relevance of cell microenvironments for the appearance of lympho-haemopoietic tissues in primitive vertebrates
    (Murcia : F. Hernández, 1995) Zapata, A.G.; Torroba, M.; Vicente, A.; Varas, A.; Sacedón, R.; Jiménez, E.
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    Thymic alterations induced by partial hepatectomy: upregulation of glycoprotein 96, CD91 and TLR2 and generation of regulatory T cells
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Jakovac, Hrvoje; Ćuk, Mira; Trobonjača, Zlatko; Mrakovčić-Šutić, Ines; Radošević-Stašić, Biserka
    Glycoprotein 96 (gp96) is an endoplasmic reticulum (ER)-resident heat shock protein. It controls the folding of nascent membrane-spanning and secretory proteins, participates in stress-induced unfolded protein response (UPR) and in pathways leading to proteolysis of damaged proteins through ER-associated degradation pathways and chaperone-mediated autophagy. In addition, gp96 controls the steroid biosynthesis and Ca2+ homeostasis and participates in insulin-IGF/signaling pathways. Besides, owing to its peptide chaperone capacity and ability to interact with antigen-presenting cells, gp96 has been implicated in priming of innate and adaptive immunity. In an attempt to visualize the intensity of ER-stress in thymus and possible participation of gp96 in generation of auto-reactive T cell clones that were detected in regenerating liver, in this study we investigated the dynamics of gp96 expression in partially hepatectomized (pHx) and sham Hx mice. Simultaneously, we detected the thymic expression of receptors responsible for endocytosis of gp96- chaperoned peptides (CD91) and intracellular activation of ER-stress pathways (TLR2), as well as the expression of TGF-β and the distribution of CD4+CD25+FoxP3+ cells. The data have shown that both pHx and sham Hx induced an accelerated apoptosis and hypoplasia in thymus. Partial Hx induced, however, a higher expression of gp96, the translocation of the CD91, TLR2 and TGF-β immunostaining from medulla to cortex and an appearance of Treg cells. The data show that pHx triggers in thymus the ERstress and UPR response and suggest that gp96 participates in the generation of natural Treg cells, which might be involved in the control of liver regeneration in the periphery.
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    Thymus x faustinoi, híbrido nuevo del sureste de la Península Ibérica
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 2004) López Espinosa, José Antonio; Sánchez Saorín, Francisco J.; Morales Valverde, Ramón; Sánchez Gómez, Pedro; Biología Vegetal; Facultad de Biología
    Se describe el nuevo híbrido Thymus x faustinoi, encontrado en la Región de Murcia entre poblaciones de Th. mastichina subsp. mastichina y Th. granatensis subsp. micranthus e intermedio morfológicamente entre ambos taxones. Además se listan los híbridos nuevos descritos de este género para la Península Ibérica en los últimos 9 años.
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    Vascular and stromal changes in irradiated and recovering rat thymus
    (Murcia : F. Hernández, 1999) Wang, Y.L.; Tokuda, N.; Tamechika, M.; Hashimoto, N.; Yamauchi, M.; Kawamura, H.; Irifune, T.; Choi, M.; Awaya, A.; Sawada, T.; Fukumoto, T.
    To analyze the mechanisms responsible for thymocyte proliferation, maturation and migration in the thymus, the rat thymus just after, and recovering from irradiation was studied morphologically. The vascular structures of the rat thymus after a radiation dose of 6 Gy were found to be destroyed on day 3, but had recovered to almost normal by day 7, suggesting that the abrupt recovery of thymus structure after irradiation was due primarily to this change in vascular structure. Furthermore, the epithelial tissues in the thymic cortex appeared to contribute to this abrupt proliferation, and possibly to the abrupt maturation of thymocytes, while medullary epithelial tissues remained sparse and appeared inactive for a relatively long period. These findings are considered important for understanding the interrelationship between thymic epithelial cells and thymocytes with respect to thymocyte proliferation, maturation and migration.