Bone marrow angiogenesis and mast cell density increase simultaneously with progression of human multiple myeloma

Immunohistochemical, cytochemical and ultrastructural data showing vivid angiogenesis and numerous mast cells (MCs) in the bone marrow of 24 patients with active multiple myeloma (MM) compared with 34 patients with non-active MM and 22 patients with monoclonal gammopathy of undetermined significance (MGUS) led us to hypothesize that angiogenesis parallels progression of MM, and that MCs participate in its induction via angiogenic factors in their secretory granules. © 1999 Cancer Research Campaig

The analysis of the dermal collagen matrix in the absence of α11β1-integrins suggests a potential role for integrins α11β1 in the regulation of skin biomechanics

Integrins \u3b111\u3b21 are major collagen receptors and are thought to play a central role in fibrillar collagen arrangement [1;2], but this has not been demonstrated in vivo. In order to answer this question, here, we analysed the overall organisation of the dermal collagen network fibril diameter in samples of back skin of \u3b111\u3b21-integrin-deficient mice (KO). Dermal collagen organisation was assessed for its complexity and its heterogeneity on paraffin sections after Sirius red staining (4 KO and 4 controls), by quantifying fractal dimension and lacunarity respectively. The results showed that fractal dimension was increased in KO mice (1,40\ub10,06 in \u3b111\u3b21 KO mice vs 1,24\ub10,05 of control mice, p=0,009), whereas Lacunarity was reduced (0,78\ub10,06 in \u3b111\u3b21 KO mice 0,97\ub10,02 of control mice p=0,002), indicating a re-organisation of the dermal collagen network in absence of integrins \u3b111\u3b21. Fibril diameter was studied in images taken at the Transmission Electron Microscope (5 KO and 5 controls). The total number of fibrils examined was 22,212 (for the 5 controls) and 28,446 (for the 5 KO). The analysis showed a proportional increase in smaller fibrils with a proportional decrease in larger fibrils in \u3b111\u3b21 KO mice, being these differences were most evident in fibrils with smallest (120nm) diameter. Chi squared test confirmed statistical significance of these changes (equivalent to p=0,001). Given the fundamental role of dermal collagen in skin stability, these changes in collagen organisation and fibril size also suggest a potential implication of \u3b111\u3b21 integrins in the control of skin biomechanics

Sequential morphological characteristics of murine fetal liver hematopoietic microenvironment in Swiss Webster mice

Embryonic hematopoiesis occurs via dynamic development with cells migrating into various organs. Fetal liver is the main hematopoietic organ responsible for hematopoietic cell expansion during embryologic development. We describe the morphological sequential characteristics of murine fetal liver niches that favor the settlement and migration of hematopoietic cells from 12 days post-coitum (dpc) to 0 day post-partum. Liver sections were stained with hematoxylin and eosin, Lennert’s Giemsa, Sirius Red pH 10.2, Gomori’s Reticulin, and Periodic Acid Schiff/Alcian Blue pH 1.0 and pH 2.5 and were analyzed by bright-field microscopy. Indirect imunohistochemistry for fibronectin, matrix metalloproteinase-1 (MMP-1), and MMP-9 and histochemistry for naphthol AS-D chloroacetate esterase (NCAE) were analyzed by confocal microscopy. The results showed that fibronectin was related to the promotion of hepatocyte and trabecular differentiation; reticular fibers did not appear to participate in fetal hematopoiesis but contributed to the physical support of the liver after 18 dpc. During the immature phase, hepatocytes acted as the fundamental stroma for the erythroid lineage. The appearance of myeloid cells in the liver was related to perivascular and subcapsular collagen, and NCAE preceded MMP-1 expression in neutrophils, an occurrence that appeared to contribute to their liver evasion. Thus, the murine fetal liver during ontogenesis shows two different phases: one immature and mainly endodermic (<14 dpc) and the other more developed (endodermic-mesenchymal; >15 dpc) with the maturation of hepatocytes, a better definition of trabecular pattern, and an increase in the connective tissue in the capsule, portal spaces, and liver parenchyma. The decrease of hepatic hematopoiesis (migration) coincides with hepatic maturation

Angiogenesis extent and macrophage density increase simultaneously with pathological progression in B-cell non-Hodgkin's lymphomas

Node biopsies of 30 benign lymphadenopathies and 71 B-cell non-Hodgkin's lymphomas (B-NHLs) were investigated for microvessel and macrophage counts using immunohistochemistry and morphometric analysis. Both counts were significantly higher in B-NHL. Moreover, when these were grouped into low-grade and high-grade lymphomas, according to the Kiel classification and Working Formulation (WF), statistically significant higher counts were found in the high-grade tumours. Immunohistochemistry and electron microscopy revealed a close spatial association between microvessels and macrophages. Overall, the results suggest that, in analogy to what has already been shown in solid tumours, angiogenesis occurring in B-NHLs increases with tumour progression, and that macrophages promote the induction of angiogenesis via the release of their angiogenic factors. © 1999 Cancer Research Campaig

Localization of Apaf1 gene expression in the early development of the mouse by means of in situ reverse transcriptase-polymerase chain reaction

Apoptosis is an essential ubiquitous process that controls the duration of the life span of cells, thus playing a crucial role in morphogenetic, histogenetic, and phylogenetic developmental processes. Apaf1 (apoptosis protease activating factor 1) is one of the central mediators of the intrinsic apoptotic pathway and a part of the apoptosome, which activates procaspase-3 and promotes cell death. Gene knockout of Apaf1 in mice leads to late embryonic lethality with malformations such as the persistence of interdigital webs and hyperplasia of brain and retina. Therefore, Apaf1 is generally believed to play a crucial role in developmental apoptosis and have a widespread expression. However, its pattern of expression in early development remains unknown. To specify whether Apaf1 indeed plays this key role, we investigated the pattern of gene expression for Apaf1 in mouse embryos on day 7,9, and 12 of development. Our results show, that gene expression for Apafl first occurs within the embryo between day 7 and 9 of development, becoming more widespread toward day 12 and then includes structures, such as yolk sac, mesenchyme, cartilage, heart anlage, otic vesicle, peridermis, and anlagen of the spinal ganglia and vertebral bodies. Our results also show that gene expression for Apaf1 is not ubiquitous in early mouse development. This finding indicates that cell death processes are independent of or less dependent on Apaf1 during this time. Of interest, an active gene expression for Apafl is also present in organ anlagen such as heart or intestine, in which no obvious phenotype is seen after Apafl deletion. This finding suggests a possible role for Apafl in such anlagen as a putative alternative compensatory pathway, which could he switched on in the case of defects in the mediators that are normally involved in such organs. (c) 2005 Wiley-Liss, Inc

Ultrastructural localization of integrin subunits α α 3 and α α 6 in capillarized sinusoids of the human cirrhotic liver

Normal liver sinusoids are not lined by a basement membrane (BM). In contrast, in the course of development of liver cirrhosis, a structured BM is formed de novo in the space of Disse. This BM contributes to the inhibition of the metabolic function of the liver but the pathogenic background of the formation of this perisinusoidal BM is still unclear. Integrins of the ß1-class are generally essential for BM stability and some of them (such as α 2ß1, α 3ß1 and α 6ß1) appear de novo in the perisinusoidal space of the cirrhotic liver. Their cellular distribution in capillarized sinusoids as well as the correlation between their cellular distribution and the formation of the microvascular BM in the cirrhotic liver has not been shown at the ultrastructural level. In the present work we aimed to clarify this issue. We focused on integrins α 3ß1 and α 6ß1 and localised them ultrastructurally in human cirrhotic liver microvessels using postembedding immunogold which allows the ultrastructural localization of antigens with high resolution in the tissue. The newly formed basement membrane of capillarized sinusoids was visualized by means of fixation with addition of tannic acid, which enables the visualization of structures of the extracellular matrix with the highest resolution. Also, we carried out laminin detection using postembedding immunogold. Our results show that both α 3ß1 and α 6ß1 are expressed on the surface of both hepatocytes and endothelial cells, i.e. on both sides of the newly formed basement membrane. This latter shows zones of higher density both in close proximity to the endothelial and to the hepatocytic surfaces which resemble laminae densae. We propose that hepatocytes and endothelial cells may, therefore, by expressing such integrins, contribute to the formation of this pathological BM in the microvessels of the human cirrhotic liver. On stellate cells, which are major producers of BM components, both integrins α 3ß1 and α 6ß1 were also localized

Soft tissue landmarks for tibial baseplate rotational alignment in total knee arthroplasty. A cadaveric study

Introduction: The tip of the tibial tubercle (TTT) is used to assess tibial baseplate rotation in total knee arthroplasty (TKA) however it can be difficult to palpate and visualise intra-operatively. Several more easily accessible soft-tissue structures have been proposed as intra-operative assessments, including the patellar tendon's medial border (MBPT) and the junction of the medial third of the patellar tendon (mt-PT). No studies have described the relationship between the TTT and these proposed landmarks. The aims of the study were to 1) determine the relationship of the soft tissue landmarks to the TTT, and 2) identify any sex differences in these measures. Materials and Methods: Measurements of the position of these soft tissue landmarks relative to the TTT were made on 56 cadaveric knees (28 female) by two observers at the level of the standard tibial cut (10 mm distal to the lateral tibial plateau). The results obtained were compared by sex and side. Results: On average, 50.7% (SD 6.79, range 33.1 - 63.1%) of the patellar tendon footprint was medial to the TTT. There were no significant differences between the sexes or left and right lower limbs. However, there was large variability in the position of all the soft tissue landmarks relative to the TTT. Conclusions: The results indicate that on average, the patellar tendon footprint is evenly spread around the TTT. However, there is a large variability in the anatomical relationship between the soft tissue landmarks and the TTT. Caution is advised if relying on these structures intra-operatively