Histology and histopathology Vol.17, nº 2 (2002)
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- PublicationOpen AccessTumor-associated fibroblasts (Part I): active stromal participants in tumor development and progression?(Murcia: F. Hernández, 2002) Kunz-Schughart, L.A.; Knuechel, R.Phenotypic and functional characteristics of tumor associated fibroblasts (TAF) in contrast to normal fibroblasts are re v i e wed in this first synopsis (part I). Terms as tumor stroma, desmo-plasia, T A F , myofibroblast, and fetal-type fibroblast are defined, and experimental systems to study heterologous cell interactions are presented. While we only start to gather information on the genotype of T A F , a broad range of data deals with the e xpression profile of these cells, co v ering e.g. ECM and ECM-modulating molecules, growth factors and cytokines. Summarizing the recent state of kno w l e d g e indicates that TAF provide sources for tumor diagnosis and therap y , that ha v e to be further defined in an or g an- s p e c i f ic approach in terms of the functional impact on the tumor cell and its environment (see part II).
- PublicationOpen AccessPressure volume curve and alveolar recruitment/ de-recruitment. A morphometric model of the respiratory cycle(Murcia : F. Hernández, 2002) Escolar Castellón, J.de D.; Escolar, M.A.; Guzmán, J.; Roqués, M.H y p o t h e s i s : The changes in pulmonary volume taking place during respiration are accompanied by the opening and closing of the alveoli, with the number of alveoli open, at the same transpulmonary pressure (TPP) differing, depending on whether the lung is insufflated or deflated. Material and methods: Seventy 344 Fischer rats divided into five groups. Group 1 lungs were fixed by instilling 10% formalin through the trachea to a pressure of 25 cm H2O. The lungs of the next four groups were air- fi l l e d and fixed via the pulmonary artery: group 2 lungs were fixed in inflation at 10 cm H2O TPP; group 3 lungs were fixed in inflation at 20 cm. H2O TPP; the lungs of groups 4 and 5 were fi xed in deflation and, therefore, were inflated with air up to 27 cm. H2O to drop to 20 cm in group 4 and to 10 cm in group 5. The lungs were processed for light microscopy, carrying out a morphometric study. The results were statistically processed. Results: The lungs insufflated with liquid fixative at 25 cm of TPP reached higher values in the va r i a b l e s Pulmonary Volume, Internal Alveolar Surface (IAS) and Number of Alveoli, being statistically signifi c a n t (p<0.05) in comparison with the other four groups. In the lungs fixed in deflation, the pulmonary volume, IAS and number of alveoli were greater than in those fixed in inflation. The lungs fixed to 20 cm in deflation displayed s i g n i ficant statistical differences compared with those fi xed to 20 cm in inflation. The IAS and number of a l veoli gave good rates in relation with the pulmonary volume (r³ 0.65). Three variables were used to measure the size of the alveoli, alveolar cord, alveolar surface and Lm, but none showed significant modifications. Conclusion: This study supports the hypothesis that changes in lung volume are related to the increase/decrease in the number of alveoli that are open/closed and not to the modification in the size of the a l veoli. Alveolar recruitment is the microscopic expression of pulmonary hysteresis, since the number of alveoli open in deflation is greater than the number open during inflation.
- PublicationOpen AccessLow density lipoproteins and mitogenic signal transduction processes: Role in the pathogenesis of renal disease(Murcia : F. Hernández, 2002) Kamanna, V.S.Abnormalities in lipid and lipoprotein metabolism are commonly observed in patients with chronic renal disease. Specifi c a l l y, hyperlipidemia and the glomerular deposition of atherogenic lipoproteins (e.g., Low density lipoprotein, LDL; and its oxidized variants) are implicated in key pathobiological processes i nvo l ved in the development of glomerular disease, including stimulation of monocyte infiltration into the mesangial space, mesangial cell hy p e r c e l l u l a r i t y, and mesangial extracellular matrix deposition. This rev i ew discusses recent understanding of glomerular mitogenic responses, intracellular signaling events associated with mesangial hypercellularity in renal diseases, and the participation of cholesterol and atherogenic lipoproteins in intracellular signaling pathways involved in mesangial cell proliferation. G e n e r a l l y, the mitogenic intracellular signaling p a t h ways are regulated by the activation of series of transmembrane and cytoplasmic protein tyrosine kinases that converge into the activation of Ras and down-stream m i t o g e n - a c t ivated protein kinase (MAP kinase). A c t ivated MAP kinase, through translocating into the nucleus and the activation of various transcription factors and protooncogenes, regulate cell proliferation. The importance of mitogenic intracellular signaling in mesangial proliferative disease has only recently been recognized and showed that the activation of MAP kinase and/or cy c l i n / cyclin-dependent kinases play crucial role in different phases of cell growth cycle and hypercellularity of glomerular cells in va r i o u s experimental renal diseases. Using glomerular mesangial cells as an in-vitro model system, studies from our laboratory indicated that the accumulation of LDL and more potently its oxidized forms within the glomerulus, through the activation of membrane receptor tyrosine kinases (e.g., EGF receptor), activate Ras and MAP kinase signaling cascade leading to DNA synthesis and subsequent mesangial cell proliferation. These data suggest that atherogenic lipoproteins may act as one of the major endogenous modulators for mitogenic signaling response and cell proliferation within the glomerulus. It is reasonable to speculate that the correction or reduction of hy p e r l i p i d e m i a , glomerular lipid deposition, and the pro-oxidative milieu within the glomerulus, through the inhibition of mitogenic signaling events, may provide protective e nvironment against mesangial hypercellularity and subsequent matrix deposition, and the progression of renal disease.
- PublicationOpen AccessAbnormalities in dendritic cell and macrophage accumulation in the pancreas of nonobese diabetic (NOD) mice during the early neonatal period(Murcia : F. Hernández, 2002) Charré, S.; Rosmalen, J.G.M.; Pelegri, C.; Alves, V.; Leenen, P.J.M.; Drexhage, H.A.; Homo-Delarche, F.Dendritic cell (DC), macrophage (Mø) and l y m p h o cyte infiltrations have been observed in normal human perinatal pancreata, but have never been investigated so early in control mice. In type 1 diabetesprone NOD mice, these cells are thought to infiltrate first the periphery of the islets of Langerhans around weaning before further islet infiltration and ß-cell destruction. We quantified, during the first month of life, the numbers of DC (characterized by CD11c positivity and dendritic morphology), histiocyte-like Mø (characterized by ER-MP23 positivity) and Mø with scave n g i n g potential (characterized by BM8 positivity) in C57BL/6, DBA/2 and BALB/c control, and NOD and lymphocytedeficient NODscid mouse pancreata. First, CD11c+ DC were present at low densities from birth onwards in control pancreata, while densities were higher in NOD and NODscid. Second, high numbers of BM8+ and ER-MP23+ Mø were observed at birth in all strains investigated. After birth, particularly BM8+ cells disappeared progressively in control strains, but not in NOD and NODs c i d. Third, NOD mice also had more E R - M P 2 3+ Mø at birth compared to controls. Finally, DC and Mø localizations were similar in all strains, i.e., mostly as dispersed cells in periva s c u l a r, periductular, peri-islet areas and interlobular septa. The most remarkable finding was that particularly BM8+ Mø, were seen at sites of islet neogenesis and predominantly at the duct-islet interface. Our data showed that different types of APC were present in the pancreas during postnatal development in various control mouse strains and some differences were o b s e r ved in NOD and NOD s c i d mice from birth onwards.
- PublicationOpen AccessCounting particles in tissue sections: Choices of methods and importance of calibration to minimize biases(Murcia : F. Hernández, 2002) von Bartheld, C.S.Investigators must choose between counting methods to quantify microscopic particles in tissues. The c o nventional profile-based ("model-based" or "2D-") counting methods have been criticized for their potential biases due to assumptions about shapes, sizes, and orientation of particles when converting profile counts into cell numbers. New stereological methods ("designbased" or "3D-") methods such as the optical disector or p hysical disector were initially introduced as being inherently unbiased. Recent calibration analyses and comparisons of results from different investigators have r evealed the potential for significant biases in the most efficient and most frequently used design-based method, the optical disector. This rev i ew aims to objective l y assess the strengths and limitations of current profi l e - and disector-based cell counting methods by examination of studies in which these methods have been calibrated against the "gold-standard", counts obtained by 3-dimensional reconstruction of serial sections. Advantages and disadvantages of each counting method and the associated embedding and sectioning techniques are compared and frequent mistakes and pitfalls of each technique are discussed. The importance of a calibration step for each technique is emphasized, and a protocol is provided for a quick and simple calibration by a "sampling" 3-D reconstruction of limited serial sections. Trends in the usage of counting methods are analyzed in four major journals. It is hoped that this r ev i ew will be helpful, for both inv e s t i gators and manuscript rev i ewers, in clarifying some of the contentious issues in the choice and implementation of appropriate methods for particle counting in tissue sections.