Histology and histopathology Vol.21, nº12 (2006)

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http://hdl.handle.net/10201/177442

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Morphogenesis of rat experimental pulmonary emphysema induced by intratracheally administered papain: changes in elastic fibres
(Murcia : F. Hernández, 2006) Sánchez-Gascón, F.; Girona, J.C.; Bernal-Mañas, C.M.; Morales, E.; Canteras, M.; Beltrán Frutos, Ester; Pastor García, Luis Miguel
The ultrastructural changes of elastic fibres in emphysematous lungs have been studied in men, but few works exist on this topic in experimental emphysematous animals. In this paper, the morphogenesis of emphysema and alterations of the elastic fibres produced by the instillation of papain are described by light and electron microscopy. Wistar rats were instilled through the trachea with papain at a rate of 3 mg/100 g animal weight. The animals were sacrificed 12 h, 3 days, 10 days and 60 days after enzyme instillation. The "Mean Linear Intercept" (MLI), the "Number of fenestrations/respiratory units" (NF) the “Number of macrophages per mm of alveolar wall” (NM) and the "Number of respiratory unit/mm2” (RU), both in the control and experimental groups were studied. Two months after treatment, the experimental group showed a strong increase in the MLI (p<0.001) and NF (p<0.001), and a diminished number of RU (p<0.05) compared with the control group. Partial correlation analysis showed a positive correlation only between MLI and NF. Twelve hours after papain instillation an inflammatory response was observed, the elastic fibres were ruptured, while the microfibrilar component remained. New formations of eulanin elastic fibres were observed three days post papain instillation. After ten days the interalveolar oedema had disappeared and the elastic fibres were of normal morphology although irregular groups of strips of elastic fibres were evident. A mixed pattern of panlobular, centrilobular and normal lung zones were observed. Two months after papain instillation abundant accumulations of elastic fibres of irregular outline were observed associated to collagen fibres. In conclusion, the morphometric parameters studied showed a significant progression of the emphysema. The strong correlation between NF and MLI suggested that papain-induced emphysema is principally caused by breaches of the alveolar walls. The results seem to point to a very abnormal remodelling process associated with elastic fibre regeneration, although there were no signs of destruction of these new fibres formed in emphysematous rat lung induced by papain.
Open Access
Natural IgM antibodies: from parias to parvenus
(Murcia : F. Hernández, 2006) Vollmers, H.P.; Brändlein, S.
Over the years, natural IgM antibodies were considered as the parias among the immune competent molecules. Their characteristic properties, like low affinity, cross-reactivity and pentameric structure, were assessed as difficult and nebulous. Today, mainly based on the persistent work of a few researchers and the key discoveries on innate immunity, natural IgM antibodies are “back on stage”. Their important role in the immune response against invasive particles, modified selfcomponents and altered cells is accepted. All the so far negatively judged features have to be seen in a different light, e.g. low affinity seems to be good for function and does not exclude specificity, cross-reactivity is no longer judged as unspecific, but instead as a very economic way of immune recognition and the pentameric structure is important for binding capacity and functional activities. In addition, with the use of natural IgM antibodies, a new field of tumour-specific targets has been encountered, the carbo-neo-epitopes, which are commonly found on post-transscriptionally modified membrane receptors. Having understood the typical features of natural IgM antibodies, their renaissance opens a new area of cancer therapeutics and diagnostics.
Open Access
Bone allograft non-union is related to excessive osteoclastic bone resorption: A sheep model study
(Murcia : F. Hernández, 2006) Laird, R.K.; Pavlos, N.J.; Xu, J.; Brankov, B.; White, B.; Fan, Y.; Papadimitriou, J.M.; Wood, D.J.; Zheng, M.H.
Using a sheep femoral allograft model we have investigated the cellular and molecular mechanisms associated with non-union of bone allografts. Histomorphometric analysis revealed that allograft nonunions featured both marked increases in osteoclast (OC) numbers and total eroded bone surface as compared to allografts wich had undergone direct union. Three distinct cellular layers lying adjacent to the allograft bone surface were identified in all non-union cases. The outer or fibroblastic layer contained an abundance of fibroblasts and connective tissue. Circumscribing this layer was a band of synovial-like cells consisting mainly of large spindle-shaped mononuclear cells mixed with scattered round-shaped mononuclear cells. The third layer, which was directly juxtaposed to the allograft bone surface, consisted predominantly of multinuclear OCs which were positively identified by calcitonin receptor immunohistochemistry. Interestingly, in-situ hybridisation revealed that surrounding synovial-like cells in non-union allografts, expressed abundant gene transcripts for receptor activator NF-kB ligand (RANKL), a membrane bound factor critical for both the induction of OC activity and osteoclastogenesis. We propose that excessive bone resorption by host OCs contributes, at least partially, to the failure of bone allografts. The production of RANKL by synovial-like fibroblasts may be the driving force responsible for the elevated generation and activation of OCs. Based on such evidence novel therapeutic strategies for the treatment of non-union bone allografts using anti-bone resorbing agents may be devised.
Open Access
Cellular proliferation, differentiation and apoptosis in polyether-polyurethane sponge implant model in mice
(Murcia : F. Hernández, 2006) Campos, Paula P.; Andrade, Silvia P.; Moro, L.; Ferreira, M.A.N.D.; Vasconcelos, A.C.
The integration of implanted material to host organism requires spatial and temporal organization of several cellular processes, such as proliferation, differentiation and apoptosis. Despite the clinical relevance of these processes, there is little information regarding the sequence of such events in synthetic matrices. Here, we present a combination of techniques used to characterize the fibrovascular response in subcutaneous polyether-polyurethane sponge implants in mice at days 4, 7, 10 and 14 postimplantation. The AgNOR technique was modified and used as a surrogate marker for proliferating and activated cells invading the implant. The number of AgNOR-stained cells increased progressively from day 4 (606±76) to day 14 (2146±71) postimplantation. The number of TUNEL-positive (apoptotic index) cells also increased progressively from day 4 (459±40) to day 14 (1157±119) postimplantation. However, the ratio of TUNEL-labeled/proliferating cells had its highest peak in the early phase of the process remaining stable until day 14. Using Picrosirius staining it was shown that thin collagen increased from day 4, peaking at day 10 and falling markedly at day 14, whereas dense collagen increased progressively during the whole period. These experiments hold potential to investigate not only distinct phases of tissue repair induced by synthetic matrices but also to study underlying mechanisms involved
Open Access
Chronic hypoxia alters calbindin D-28k immunoreactivity in lingual and laryngeal taste buds in the rat
(Murcia : F. Hernández, 2006) Yoshida, T.; Matsuda, H.; Yamamoto, Y.; Hayashida, Y.; Tsukuda, M.; Kusakabe, T.
The distribution and abundance of the calcium binding protein, calbindin D-28k (CB) immunoreactivity in the taste buds of the circumvallate papillae and larynx were compared between normoxic and chronically hypoxic rats (10% O2 for 8 weeks). In the normoxic rats, CB immunoreactivity was observed in some cells and fibers of the intragemmal region of the taste buds in the circumvallate papillae. In contrast, in the subgemmal region of the laryngeal taste buds, fibers but not cells were immunoreactive for CB. In chronically hypoxic rats, CB immunoreactive cells and fibers in the taste buds were decreased in the circumvallate papillae. In the laryngeal taste buds, the density of the subgemmal CB immunoreactive fibers in chronically hypoxic rats was greater than in normoxic rats. It is considered that function of the laryngeal taste buds is different from that of the lingual taste buds, so that laryngeal taste buds may be involved in chemosensation other than taste. The altered density of CB immunoreactive cells and fibers in the lingual and laryngeal taste buds is a predominant feature of hypoxic adaptation, and chronic hypoxic exposure might change the chemical sensitivity of the circumvallate papillae and larynx through the regulation of intracellular Ca2+

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