Histology and histopathology Vol.18, nº 3 (2003)
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- PublicationOpen AccessLocalization of integrin αvß3 and vascular endothelial growth factor receptor-2 (KDR/Flk-1) in cutaneous and oral melanomas of dog(Murcia: F. Hernández, 2003) Rawlings, N.G.; Simko, E.; Bebchuk, T.; Caldwell, S.; Singh, B.Melanomas are common neoplasms of dogs and arise from pigment-producing cells called melanocytes or melanoblasts. Melanomas of skin are often easily cured by surgical excision, but those of oral mucosa are aggressive, metastasize to the regional lymph nodes and lungs, and respond poorly to conventional therapy. Tumor growth is sustained by proliferation of microvessels via a process called angiogenesis. Integrin α vß3 is expressed in proliferating but not in quiescent microvessels suggesting a role in angiogenesis. Vascular endothelial growth factor (VEGF) manifests its mitogenic and angiogenic effects mainly via VEGF receptor-2 (VEGFR-2/Flk-1). We conducted this immunocytochemical study to investigate the expression of integrin α vß3 and VEGFR-2 in archival and fresh samples from cases of canine melanomas. Results show that integrin α vß3 was expressed in 72% and 88% of cutaneous and oral melanomas, respectively, and the expression was restricted to and immediately around the melanocytes and endothelial cells. VEGFR-2 staining of selected cases of melanoma revealed that its expression overlapped with the α v β 3 integrin. Dual immuno-gold electron microscopy confirmed co-localization of integrin α vß3 and VEGFR-2 in melanocytes and endothelial cells. These data demonstrate expression and co-localization of integrin α vß3 and VEGFR-2 in cutaneous and oral melanomas of dogs.
- PublicationOpen AccessThe influence of different fibrous supplements in the diet on ruminal histology and histometry in veal calves(Murcia : F. Hernández, 2003) Di Giancamillo, A.; Bosi, G.; Arrighi, S.; Savoini, G.; Domeneghini, C.The aim of this study was to determine whether the administration of four different solid feeds would influence selected morphological and morphofunctional aspects of the rumen mucosa in veal calves. The fibrous supplementation of the liquid diet of veal calves has been provided by recent EU formulation (EC Council Directive 91/629/1991; EC Council Directive 97/2/1997). Twenty-five Holstein calves were assigned to either exclusively liquid diet (milk replacer, control), or pelleted feed, corn silage, extruded feed, dried corn silage. The morpho-functional effects of the fibrecontaining diets were examined evaluating histological and histometrical characteristics of ruminal mucosa after the slaughter of calves. There were slight to severe histological abnormalities in the rumens of all animals examined. The severe histological abnormalities were present in calves given pelleted feed, corn silage, and extruded feed. Dried corn silage caused less ruminal damage. We found that the length and epithelial thickness of ruminal papillae were higher in control veal calves than in dietary fibre-supplemented animals. The results of the present study, even if partially, support the EU prescription in the use of fibre diets in veal calves as integration of the traditional milk replacer diet.
- PublicationOpen AccessRNA is closely associated with human mast cell lipid bodies(Murcia : F. Hernández, 2003) Dvorak, A. M.; Morgan, E.S.; Weller, P.F.Both novel and multiple ultrastructural studies based on different principles show relationships of cytoplasmic lipid bodies and ribonucleic acid (RNA) of potential importance to RNA metabolism in human mast cells. The methods include general ultrastructural morphological observations, imaging of RNA with an EDTA regressive stain, imaging of the incorporation of radio labeled uridine by ultrastructural autoradiography, postembedding immunogold labeling of uridine, ribosomes and small nuclear ribonuclear proteins and ultrastructural in situ hybridization detection of poly(A)- positive messenger RNA. Altogether these studies implicate human mast cell lipid bodies in RNA metabolism and are analogous to earlier similar studies which showed that human mast cell granules also curtain RNA.
- PublicationOpen AccessInterleukin-7 (IL-7) and IL-7 receptor (IL-7R) signalling complex in human solid tumours(Murcia : F. Hernández, 2003) Al-Rawi, M.A.A.; Mansel, R.E.; Jiang, W.G.Interleukin-7 (IL-7) plays an important role in the normal development and maintenance of the human immune system. Its effects are mediated via its receptor, IL-7R. Ligand-receptor engagement results in a cascade of phosphorylation events mediated by various molecules including the Janus kinases (Jak1 and Jak3), PI3-kinase, Stats (signal transducers and activators of transcription) and other molecules. The activation of IL- 7 signalling pathway results in survival, proliferation, differentiation and maturation of haematopoietic cells including B and T lymphocytes. Although the relationship of IL-7 with the development and differentiation of some haematological cancers like leukaemias and lymphomas is well recognised, little is known about it involvement with solid tumours. There are several studies that have revealed IL-7/IL-7R expression in epithelial systems and some human solid epithelial tumours. Furthermore, IL-7 can be produced by some human tumour cells and involved in tumour development and progression. In this review article we have summarised the main biological activities of IL-7 and its downstream signalling complex in relation to some human solid malignancies.
- PublicationOpen AccessThe pathobiologic spectrum of Schwannomas(Murcia : F. Hernández, 2003) Kurtkaya-Yapicier, O.; Scheithauer, B.W.; Woodruff, J.M.In terms of their morphology, clinical associations and behavior, peripheral nerve sheath tumors are among the most varied of human neoplasm. Not surprisingly, such tumors are subject to frequent misdiagnosis. This is particularly true of the spectrum of schwannomas which include: a) conventional schwannoma, a histologically benign tumor which, on occasion, is destructive of surrounding osseous structures, b) the relatively recently described cellular schwannoma, a tumor that histologically simulates malignant peripheral nerve sheath tumor (MPNST), c) plexiform schwannoma which, particularly in cellular form and when occurring in childhood, simulates MPNST, and d) melanotic schwannoma which is often mistaken for melanoma. The psammomatous form of the latter is often associated with Carney complex, a rare heritable disorder that: a) includes cutaneous lentigines, b) myxomas of skin, subcutaneous tissue, and heart, c) and endocrine neoplasms. The tendency to misdiagnose schwannomas and to overestimate their grade makes schwannomas worthy of note. Herein, we discuss the four major schwannoma variants, their essential clinicopathologic features, and differential diagnosis. The distinction from MPNST is given particular attention.