Given the importance of the thymus to the immune system and the limited knowledge about its development and involution processes, this study evaluated the expression of the vascular endothelial growth factor, a key angiogenic factor for the formation of vascular tissue bed and modulation of functions related to cell proliferation and migration, hormone synthesis, and immunomodulation. In this study, thymus samples of dog fetuses (30, 40, 50 and 60 days old), and young (180 days old) and adult (365 days old) dogs were submitted to real-time PCR and Western blot. Timedependent changes were observed for proteins and genes associated with the development of the vascular system, such as VEGF-A, VEGF-C, Flt-1, KDR, FLT-4, and EG-VEGF. This result demonstrates that these system components play different roles during development and involution of the thymus. Possible functions, such as the modulatory effect on vasculogenesis and microenvironment, influence the proliferation and differentiation of thymocytes, T cells maturation, cell-cell interaction and hormone secretion.

A preocupação com o meio ambiente vem sendo uma preocupação de todas as empresas no mundo inteiro. Com isso, a Logí­stica Reversa (LR) está sendo abordada com maior frequência, conhecida também como logí­stica inversa é uma fração da logí­stica que trata do retorno dos produtos, resí­duos e/ou materiais utilizados na produção. O presente artigo através de entrevista em uma grande empresa da região norte do Paraná tem o propósito de analisar as dificuldades e desafios enfrentados pelas empresas em realizar a logí­stica reversa de modo a cumprir com a legislação pertinente bem como em manter seus custos e encontrar na região empresas que atendam às suas necessidades no descarte de materiais.

Considering the spleen great importance for the immune system and the role of this organ in response to Feline Leukemia Virus (FeLV) infection in response to Feline Leukemia Virus (FeLV) infection, the objective of this study was to evaluate spleen histomorphometric changes, as well as its weight and volume. Furthermore, lymphocytes were quantified and the VEGF system expression was analyzed, especially its VEGF-A protein, which is part of physiological angiogenesis in different body organs. Spleens of infected and non-infected cats of six months to three years old were collected and used for confection of histological slides, which passed through the coloration process and immunohistochemistry technique. We observed state of splenomegaly, however, there were no statistically significant histomorphometric changes. Presence of lymphocytes was significantly reduced in the diseased group when compared with the control. On the other hand, there was a statistically significant increase in the VEGF-A protein expression.

The functions of the cloacal bursa are not known in great detail; therefore, detailed morphophysiological studies are necessary to elucidate the relationship between this structure and the immunity of birds. A quantitative analysis was performed to determine the volume density of lymphocytes (Vv[lymphocytes]) and connective tissue density arranged along the organ. Cloacal bursa, from male and female Gallus gallus domesticus, aged between one and seven weeks old, were separated in seven groups according to age (G1 to G7). Histological sections were stained with hematoxilin-eosin and Picrosirius red to differentiate lymphocytes and connective tissue, respectively. Vv(lymphocytes) increased up to 4 weeks, decreasing in subsequent weeks. Connective tissue density increased throughout the seven weeks studied. Areas of intense lymphopoiesis were observed from G1 to G4 and areas of distancing between the cells and early tissue necrosis were observed from G5 to G7. Therefore, the increase in the lymphocytes number expected during the development and maturation periods of the cloacal bursa occurred in the first four weeks. From that period, the involution process started, lymphoid depletion was observed while connective tissue density increased. These processes occurred as simultaneous and inversely proportional events during the remodeling process of the organ. A bolsa cloacal apresentou alterações em sua constituição ao longo das sete semanas analisadas. As expected and described in literature, the main alterations observed were the lymphocyte depletion and the increasing in connective tissue density that did not follow a regular pattern, but occurred in simultaneous events and in a inversaly proportional way.

The feline leukemia virus (FeLV) is a complex disease that affects mainly the immune and hematological systems of cats. And because the thymus was closely associated with the immune system, the aim of this study was to quantify the morphological changes in the thymus of naturally infected and uninfected animals. Thymus morphological changes were evaluated by quantifying the following parameters: thymocytes, fat tissue, thymic corpuscles, connective tissue, and type I and III collagen. This study analyzed a total of seven cats, five in the negative group (Fn) and two in the positive (Fp) group. The areas occupied by thymocytes in FeLV negative (Fn) and positive (Fp) animals were, respectively, 55.16% ± 6.15% and 44.81% ± 6.15% (p = 0.39); adipocytes, 42.14% ± 5.97% (Fn) and 53.42% ± 11.3% (Fp) (p = 0.34); blood vessels, 0.85% ± 0.24% (Fn) and 1.75% ± 0.52% (Fp) (p = 0.15). Whereas thymic corpuscles occupied an area of 0.68% ± 0.19% in negative animals (Fn) only. The connective tissue covered area varied between 12.05% ± 0.68% (Fn) and 10.34% ± 0.62% (Fp) (p = 0.009). Collagen type I (p = 0.30) and type III (p = 0.59) were present in, respectively, 1.73% ± 0.3% and 0.44% ± 0.09% in Fn, and 1.44% ± 0.36 and 0.44% ± 0.13% in Fp. The FeLV virus was not able to completely modify the thymus structure of infected animals, considering the areas occupied by thymocytes, adipose tissue, blood vessels and also type I and III collagens. However, the connective tissue underwent a certain degree of remodeling since less connective tissue area was observed in FeLV infected animals. The absence of thymic corpuscles in immunosuppressed animals suggests a possible connection to thymopoiesis.