Differential expression of tenascin-C in the developing human lung: an immunohistochemical study.

Much of the specification for the basic embryonic body plan is the result of a hierarchy of developmental decisions at different developmental times. The extracellular matrix (ECM) appears to be a very dynamic structure during embryogenesis. One of the mesenchymal ECM proteins, tenascin, is reported to be transiently expressed during embryonic tissue development, and is absent or much reduced in most fully developed organs. The respiratory system is an outgrowth of the ventral wall of the foregut, and the epithelium of the larynx, trachea, bronchi and alveoli is of endodermal origin. The cartilaginous and muscular components are of mesodermal origin. The aim of this study was to investigate the role of tenascin-C (TNC) in the developing human lung, during the pseudoglandular, canalicular and saccular stage of lung maturation. Formalin-fixed, paraffin-embedded tissue from the lungs of 30 embryos (10 corresponding to the 10th to the 16th gestational week (pseudoglandular stage), 10 to the 17th to the 23rd gestational week (canalicular stage), and 10 to the 24th to the 27th gestational week (saccular stage), were investigated by conventional histology and immunohistology for the expression levels of TNC. The changes observed in the distribution patterns suggest that during embryogenesis, the rate of tenascin synthesis changes significantly. During the pseudoglandular stage, the density of cells expressing TNC was higher in the condensing mesenchyme surrounding the epithelial glands than in the epithelial cells, whereas the inverse result was observed during the canalicular stage. During the saccular stage the pattern of immunoreactivity with TNC was lower than those of the pseudoglandular and canalicular stage, either in epithelial or mesenchymal cells, but it was highly expressed in the basement membranes. This restricted spatiotemporal distribution suggests that tenascin has a key role (1) in mesenchymal tissue remodeling during the pseudoglandular stage, a period that describes the development of the complete bronchial tree and (2) on the epithelial cell shape and function during the canalicular stage, a period that describes the formation of pneumocytes type I and pneumocytes type II. The later, will produce the surfactant, a phospholipid-rich fluid capable of lowering surface tension at the air-alveolar interface. During the saccular stage, tenascin was present mainly in the basement membranes surrounding the acinar and vascular structures, indicating a supporting and mechanical role.

Intraoperative estimation of sentinel lymph nodes in breast cancer by imprint cytology.

BACKGROUND: Frozen section biopsy has been widely used for intraoperative diagnosis and evaluation of sentinel lymph nodes, so a decision can be made regarding whether to perform axillary clearance during primary surgery. This study aims to discuss the reliability of a simpler and faster method - touch imprint cytology - in the interpretation of metastasis from breast cancer. METHODS: A retrospective review of 41 sentinel lymph node biopsies from patients with breast cancer were examined by intraoperative imprint cytology using rapid Diff-Quick staining. Paraffin-embedded permanent sections were examined using hematoxylin and eosin stained sections from the sentinel lymph nodes in collaboration with the employment of an anti-cytokeratin antibody. RESULTS: Sixteen of all sentinel nodes harbored metastases in the paraffin sections, of which all 16 were identified by imprint cytology (sensitivity 93%). CONCLUSION: Touch imprint cytology is a fast and reliable alternative for intraoperative evaluation of sentinel lymph nodes in breast cancer patients.

Induction of hepatic haematopoiesis with fibronectin expression by EMT stromal cells during the second trimester of development.

In an initial period of vertebrate phylogeny (bone marrow-less vertebrates), lymphohaematopoiesis takes place in numerous organs containing a suitable microenvironment. Among other organs (i.e., gonads, kidney and spleen), the liver is apparently the most appropriate site for homing and differentiation of haematopoietic cell precursors. Interaction between haematopoietic cells and stromal cells is important for regulation of haematopoiesis. Numerous soluble and membrane-bound factors directly regulating haematopoiesis have been documented, but little is known about the effect of the foetal hepatic epithelial-to-mesenchymal transition (EMT) stromal cells' activity and their product-fibronectin, on foetal hepatic haematopoiesis. The binding of late-stage erythroid cells to FN has been well characterised and is believed to be critical for the terminal stages of erythroid differentiation. The intention of this article is to provide a quantitative overview of FN, produced by hepatic EMT stromal cells, in foetal hepatic haematopoiesis during the first and second trimester of development. Paraffin-embedded specimens from the liver of 30 human embryos in the first and second trimesters of gestation were investigated by conventional histology and immunohistology for the presence of FN and specific haematopoietic cell types. The staining intensity, and localisation of FN and haematopoietic markers in sequential sections were examined. Furthermore, double immunohistochemical staining was performed to assess simultaneous detection of FN and haematopoietic markers. FN was expressed in the EMT stromal cells of the hepatic portal triads more strongly during the second trimester than the first. Furthermore, an intense immunostaining for haematopoietic lineages, and especially for erythropoiesis, was observed in the second trimester compared to the first. The results of the double immunostaining disclosed an intimate co-expression of the FN and CD haematopoietic markers. Foetal hepatic EMT stromal cells provide a unique microenvironment that supports the emergence, expansion and maintenance of human foetal haematopoietic development during the mid-gestational stage. FN produced by the EMT stromal cells follows a time course parallel to that of haematopoiesis. We suggest that in foetal liver, phenotypic modifications of EMT stromal cells expressing FN concerning the cell adhesion capacity of the protein are associated with proliferation and differentiation of specific haematopoietic cell lineages during the second trimester of gestation, probably reflecting the increasing demand of the growing foetus for mature erythroid and myeloid cells.

A stromal myoid cell line provokes thymic T-cell immigration at the second and third gestational trimesters.

UNLABELLED: Once lymphoid precursors enter the thymus form the blood stream, they come into contact with thymic stromal cells that guide their maturation into functionally competent T cells. Thymic myoid cells are one such cell type. They have been described as a regular constituent of the thymus of embryonic and young vertebrates and express muscle proteins including myosin, desmin, acetylcholine receptor (AChR), C-protein, MyoD, troponin T, rapsyn, and utrophin. It has been emphasized recently that the thymic myoid cells play an important role in the protection of thymocytes from apoptosis, and in the process of T-cell differentiation and maturation. AIM: To provide a quantitative estimation of thymic myoid cells and T-cell population in different stages of development. A probable interaction between these two populations could explain an additional mechanism to the active T-cell migration from the thymus that is a direct contact to a specific myoid cell line. MATERIALS AND METHODS: Paraffin-embedded specimens from the thymus of forty five human embryos at the first, second and third trimester of gestation respectively, were investigated by conventional histology, and immunohistology for the presence in the stroma of the thymic medulla, of myosin in the myoid cells, and UCHL1 (pan T-cell) antigen in the medullary thymocytes. RESULTS: Our results demonstrated a quantitative difference in the second and third trimester of development concerning the expression of myosin in the stromal myoid cells of the thymic medulla over the equivalent expression of the protein in the first trimester. Similar changes in the above periods were found concerning the population of medullary thymocytes expressing UCHL1 antigen. CONCLUSIONS: Our results indicate that: (1) Thymic myoid cells play an important role in the thymic microenvironment as they are well conserved throughout species evolution. (2) The increased population of myoid cells in the medullary area during mid and late gestational age, in comparison with first trimester, probably reflects the increased demand of the growing fetus for mature T lymphocytes. Contractions of myoid cells mediated by their cytoplasmic structural proteins, including myosin which is well preserved during development, might aid the movement of thymocytes expressing UCHL1 antigen, across or out of the gland, suggesting a potential involvement of myoid cells in the thymic function. Further studies on larger series are needed to corroborate this.

Clinicopathologic and prognostic significance of cyclooxygenase-2 expression in endometrial carcinoma.

BACKGROUND: Endometrial carcinoma is the most common malignancy of the female genital tract in the Western world. COX-2 is highly expressed in endometrial carcinoma, but there is controversy regarding its clinical role and its possible prognostic role. COX-2 expression was determined by immuno-histochemistry and was correlated to standard clinico-pathologic variables in a series of primary untreated endometrial carcinoma patients. COX-2 as an accurate predictor of the disease was also analyzed. METHODS: One-hundred and ten cases of primary untreated endometrial carcinoma hosts who were admitted to the Department of Obstetrics and Gynecology, University General Hospital of Alexandroupolis, were investigated. Immunohistochemistry was performed using rabbit polyclonal antiserum against human COX-2. RESULTS: Twenty-eight patients (25.5%) were scored as COX-2 positive. A statistically significant association was found between COX-2 overexpression and FIGO stage (p=0.010). A positive correlation was also found with histological grade (p=0.019) and myometrial invasion (p=0.026). No significant association was found with histologic type of the tumor (p=0.164). COX-2 positive patients had a significant association with sort survival (p=0.028). CONCLUSIONS: COX-2 expression is an independent clinicopathologic factor and an independent prognostic factor in endometrial carcinoma. It could be used to plan treatment modalities for hosts.