Histology and histopathology Vol.14, nº 1 (1999)

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Open Access
Molecular genetics of ovarian carcinomas
(Murcia : F. Hernández, 1999) Diebold, J.
The phenotypic variability of epithelial ovarian neoplasms correlates with a diversity of changes at the molecular level. Invasive serous and undifferentiated ovarian carcinomas are characterized by p53 mutations with p53 protein accumulation, extensive loss of genetic material of chromosome 17 and complex changes on many other chromosomes, e.g. amplification of oncogenes. These alterations are seen only in a minority of mucinous and endometrioid carcinomas, mainly in advanced stages. Overexpression of bcl-2 is seen most frequently in endometrioid carcinomas (ca. 90% of cases), which in addition show microsatellite instability in around a third of the cases, as has been described in endometrioid endometrial carcinomas. KRAS mutations are characteristic for mucinous LMP tumors and mucinous carcinomas (40-50% of cases) and are also found in a third of serous LMP tumors. In addition, serous LMP tumors show mild microsatellite instability in 30%. However, complex chromosomal aberrations are never seen in these neoplasms
Open Access
Intracellular cholesterol trafficking
(Murcia : F. Hernández, 1999) Sviridov, D.
The overall picture of intracellular cholesterol trafficking is very complex. The transfer of cholesterol within the cell depends on the contribution of several trafficking mechanisms. The known elements of cholesterol trafficking machinery include clathrin-coated pits, scavenger receptor type B1, caveolae, phospholipd rafts, Niemann-Pick C disease protein, sterol carrier protein 2, multidrug resistance protein, microsomal triglyceride transfer protein and steroidogenic acute regulation protein. Several pathways of intracellular cholesterol trafficking, for example retroendocytosis and cholesterol absorption in the intestine, are yet to be connected to specific structural elements. The contribution of different pathways depends on cell type, the source and destination of cholesterol and cellular cholesterol content and requirements. Some pathways are found in most, if not all, cell types, while others are associated with the specialized function of a particular cell type, for example, lipoprotein assembly in the liver or intestine and steroid hormone synthesis in steroidogenic tissue. Certain routes of intracellular cholesterol trafficking are heavily backed up by several auxiliary pathways, others entirely depend on a single functional element. In this review we describe the intracellular machinery involved in the intracellular transfer of cholesterol and give an overview of both the general and specialized pathways of intracellular cholesterol trafficking known to date.
Open Access
Thrombospondin-1, PECAM-1, and regulation of angiogenesis
(Murcia : F. Hernández, 1999) Sheibani, N.; Frazier, W.A.
Thrombospondin-l (TSPl) is a multidomain glycoprotein expressed by many cell types. It is a multifunctional protein with important roles in regulation of vascular cell functions. Mutation or loss of tumor suppressor genes results in down regulation of TSPl expression during malignant transformation. Thus, suggesting that down regulation of TSPl may contribute to development of the tumor angiogenic phenotype and perhaps tumor metastasis. TSPl was demonstrated to be a natural inhibitor of angiogenesis. Peptides from procollagen-like domain and type 1 repeats of TSP1, like whole TSP1, inhibit the angiogenic response to a variety of angiogenic stimuli in vivo and endothelial cell (EC) migration in vitro by directly acting on ECs. The molecular mechanisms which mediate these inhibitory effects of TSPl and its peptides are not understood. TSPl expression is down regulated in the Polyoma middle T transformed mouse brain ECs (bEND.3). This may remove the TSPl inhibitory effects allowing ECs to rapidly proliferate in culture and form hemangiomas in vivo. Re-expression of TSPl in bEND.3 cells restores a normal phenotype and suppresses their ability to form hemangiomas. This is mediated by modulating expression of several genes in concert favoring a differentiated state of endothelium. TSPl transfected bEND.3 cells down regulate expression of PECAM-1, a multifunctional endothelial cell adhesion molecule with essential roles in angiogenesis. A similar phenotype to that of TSPl transfected cells was observed when endogenous PECAM-1 levels were down regulated by anti-sense transfection of bEND.3 cells. The anti-sense PECAM-1 transfected cells turn on expression of endogenous TSPl and its angioinhibitory receptor, CD36. Expression of other genes with potential roles in regulation of EC phenotype were also affected in patterns very similar to those observed in TSPl transfected bEND.3 cells. Therefore, it appears that a reciprocal relationship exists between TSPl and PECAM-1 such that they are constituents of a "switch" that regulates in concert many components of the angiogenic and differentiated phenotype of ECs.
Open Access
The degradation of glycogen in the lysosomes of newborn rat hepatocytes: glycogen-, maltose- and isomaltose-hydrolyzing acid alpha glucosidase activities in liver
(Murcia : F. Hernández, 1999) Kalamidas, Stefanos; Kotoulas, Othon B.
The lysosomal glucosidase activities and glycogen degradation in newborn rat liver were studied by using biochemical assays, electron microscopy and quantitative morphometry. Glycogen-hydrolyzing, maltose-hydrolyzing and isomaltose-hydrolyzing activities were low at birth but increased afterwards. At the age of 6 hours they were markedly elevated. Actinomycin prevented the development of glucosidase activities indicating that these depend on protein synthesis. Parenteral glucose inhibited all three activities. This was apparently due to the abolition of normal postnatal hypoglycemia and the need for blood glucose. Cyclic AMP increased the glycogen-hydrolyzing but not the maltose-hydrolyzing activity. Propranolol inhibited the glycogen-hydrolyzing but not the maltose-hydrolyzing activity. The observations of this study provide further support for the hypothesis made by previous investigators that these activities are due to different enzymes.
Open Access
Epithelia1 integrity, cell death and cell loss in mammalian small intestine
(Murcia : F. Hernández, 1999) Mayhew, T.M.; Myklebust, R.; Whybrow, A.; Jenkins, R.
In recent years, the different mechanisms of epithelial cell loss which occur in mammalian and avian small intestine have been re-investigated. Information is now available for a variety of mammalian types and mechanisms can be divided into two major classes: [i] those preserving epithelial integrity by maintaining intercellular tight junctions throughout early-to-late stages of cell extrusion; and [ii] those which compromise integrity by introducing breaches in epithelial continuity. Both classes are associated with the activity andtor proximity of non-epithelia1 cells (mainly lymphocytes and mononuclear phagocytes) located in the epithelium or underlying lamina propria. Intraepithelial lymphocytes may be involved in enterocyte targetting and killing whilst lamina propria (LP) macrophages sequester cell debris. Where epithelial integrity is maintained, two types of loss can be identified. In the first (type l), complete cells are extruded into the lumen. In the second (type 2), only anucleate apical cell fragments pass into the lumen . There are two variants of type 2 loss distinguishable by the fate of the nucleated basal portions of cells. One variant (type 2a) creates large intercellular spaces extending from the preserved apical cap to the basal lamina and containing enterocyte debris for phagocytosis. The second (type 2b) involves the gradual shrinkage of individual cells (which become more electron-dense) and in situ degeneration of their nucleated subapical portions in increasingly narrower intercellular spaces between adjacent healthy enterocytes. The mechanism of removal of these fragments is unclear but may be via macrophages or surrounding enterocytes. Apoptosis has been implicated in both type 1 and type 2 extrusion. In contrast, type 3 loss involves morphological changes in enterocytes which are reminiscent of those seen in necrosis and is accompanied by breaks in epithelial continuity following cell swelling, a decrease in cell electron density and total or subtotal degradation of organelles and membranes. It ends in loss of either an abnormal cell apex (with subsequent exposure of the degraded cell contents and their spillage into the lumen) or a complete cell remnant (extruded into the lumen before total disintegration of plasma membranes).
Open Access
Possible involvement of DNA methylation in 5-azacytidine-induced neuronal cell apoptosis
(Murcia : F. Hernández, 1999) Nakayama, Hiroyuki; Kajikawa, S.; Shinozuka, J.; Su, W.P.; Doi, K.
Eight chemicals that are cytidine analogues or nucleosides (5-azacytidine (SAzC), 5-azadeoxycytidine, 6-azacytidine, 5-azacytosin, cytidine, 3-deazaadenine, 3-deazauridine and 6-azauridine) were examined for the ability to induce neuronal apoptosis. 5AzC and 5-azadeoxycytidine induced apoptosis in the brain and spinal cord of the fetuses at 24 hr after the injection to dams, while the other chemicals tested failed to induce apoptosis. In the system of PC12 cells, only 5AzC induced apoptosis, and other chemicals failed to provoke morphological and biochemical changes characteristic of apoptosis. SAzC, 5-azadeoxycytidine and 6-azacytidine failed to induce apoptosis in C6 cells. Gel electrophoresis after MspI or HapII digestions revealed no apparent evidence of DNA demethylation after 5AzC-treatment in either fetal brains or PC12 cells. These results indicate that DNA demethylation is possibly involved in 5AzC-induced neuronal apoptosis although no direct evidence of DNA demethylation was obtained.
Open Access
Cytokines and pulmonary inflammatory and immune diseases
(Murcia : F. Hernández, 1999) Xing, Z.; Jordana, M.; Gauldie, J.; Wang, J.
Cytokines are important soluble signalling molecules that dictate and coordinate inflammatory and immune responses. Further understanding the role of cytokines in the pathobiologic mechanisms of pulmonary inflammatory and immune diseases holds the key to the development of effective prophylactic and therapeutic strategies. In the last several years, the use of models of human pulmonary diseases established either in normal adult animals, mice deficient for a given immune cell type or cytokine, or mice engineered to overexpress a given cytokine, has remarkably facilitated our understanding of the mechanisms operating in human disease. Cytokines that are involved in pulmonary inflammatory and immune conditions may be generally divided into groups of pro-inflammatory, antiinflammatory and growth-stimulatory cytokines. While pro-inflammatory cytokines can be detrimental under such severe conditions as endotoxemia and fibrosis, they are required in host resistance against infectious agents. Anti-inflammatory cytokines play an important role in controlling the extent of tissue inflammatory/irnmune responses. Overexpression of growth-stimulatory cytokines are often directly associated with tissue fibrotic responses. In this review, the findings attained from experimental models by us and others were discussed with emphasis on cellular and histopathologic alterations, cytokine-mediated molecular mechanisms and the prospects of cytokine-based therapeutic strategies. Due to the restricted space, we chose to focus only on models for endotoxic lung, endotoxemia, acute pulmonary infections by extracellular Gram-negative bacteria, chronic pulmonary infections by intracellular myco-bacteria, allergic airways inflammation and pulmonary fibrosis.
Open Access
Systematic review and meta-analysis in anatomic pathology: the value of nuclear DNA content in predicting progression in low grade CIN, the significance of the histological subtype on prognosis in cervical carcinoma
(Murcia : F. Hernández, 1999) Heatley, M.K.
Meta-analysis, though increasingly popular in clinical medicine, has not found acceptance in anatomic pathology. This paper argues that, in combination with a systematic review of the literature, meta-analysis may be usefully applied to pathological research and two examples drawn from gynaecological pathology (the value of nuclear DNA quantitation in predicting progression in low grade cervical intraepithelia1 neoplasia and the difference in prognosis between squamous cell carcinoma and adenocarcinoma of the cervix) are included to illustrate the methods used and to demonstrate some of the difficulties associated with these techniques.
Open Access
Activin: A novel player in tissue repair processes
(Murcia : F. Hernández, 1999) Hubner, G.; Alzheimer, C.; Werner, S.
Recent studies have demonstrated a strong expression of activin in repair processes of various tissues and organs, including the skin, the lung, the intestine, the cardiovascular system, and even the brain. Although little is as yet known about the function of activin in tissue repair, first results suggest a role of activin in epithelia1 differentiation, fibroblast proliferation and expression of matrix molecules by these cells, and also in neuroprotection. Whereas a transient overexpression of activin after tissue injury might be beneficial for the repair process, sustained expression of activin could lead to fibrotic processes. Therefore, the modulation of the availability or biological activity of activin could be of particular importance for the treatment of impaired tissue repair on the one hand and tissue fibrosis on the other hand.
Open Access
Development of follicular dendritic cells: A study using short-term bone marrow cell grafting in SCID mice
(Murcia : F. Hernández, 1999) Yamakawa, Mitsunori; lmai, Yutaka; Dobashi, Michio; Kasajima, Takeshi
To evaluate the cellular origin of follicular dendritic cells (FDC) in lymphoid follicles (LFs), severe combined immunodeficient (SCID) mice (H-2d) were grafted with 5-bromo-2'-deoxyuridine (BrdU)- incorporated bone marrow cells from CB-17 mice (H-2'9 and with non-BrdU-incorporated bone marrow cells from C3H mice (H-2k) and Wistar rats (RTIU). This procedure was followed by antigenic stimulation with horseradish peroxidase and related immune complex (mouse peroxidase anti-peroxidase) administration. Secondary LFs in the lymph nodes and spleen of the reconstructed SCID mice were examined morphologically and immunocytochemically. LFs reconstructed with CB-17 mouse bone marrow cells contained FDCs capable of trapping and/or retaining mouse peroxidase anti-peroxidase as immune complexes. Secondary LFs contained BrdU-incorporated germinal center lymphocytes but not non-lymphoid stromal cells. A cell grafting study in SCID mice using bone marrow cells from C3H mice and Wistar rats demonstrated that FDCs in reconstructed LFs exhibited a marker specific for the recipient but not for the donor. These data indicate that functionally active FDCs occur de novo in reconstructed LFs in SCID mice, and do not support the view that FDCs originate from bone marrow cells in short-term reconstructed LFs.
Open Access
Lipid signaling and cell responses at the nuclear level
(Murcia : F. Hernández, 1999) Neri, L.M.; Capitani, S.; Borgatti, P.; Martelli, A.M.
The nucleus is known to be a site for an active lipid metabolism. Although phospholipids are present in the nuclear envelope, evidence suggests that they are also located further inside the nucleus. The function of these intranuclear lipids has escaped clarification for many years. Early experiments showed that they can interact with DNA double helix affecting its thermal stability and can influence RNA synthesis in isolated nuclei. However, in the last 10 years several investigations have suggested that they may be involved in signal transduction pathways at the nuclear level and a growing body of evidence supports this hypothesis
Open Access
lmmunohistochemical demonstration of metallothionein in benign and malignant canine mammary tumours
(Murcia : F. Hernández, 1999) Fuentealba, I.C.; Mullins, J.E.
Immunocytochemical demonstration of metallothionein (MT) has been reported as a useful prognostic tool in human breast cancer. The aim of this study was to determine the immunohistochemical location of MT in canine mammary tumours and its possible correlation with the morphologic characteristics of these tumours. Surgical specimens from spontaneous malignant (n=20) and benign mammary neoplasms (n=20) were processed for routine histological examination and immunohistochemical study. An indirect immunoperoxidase technique, using monoclonal antibody E9 against horse MT was employed. Intensity of the stain, the percentage of immunoreactive tumour cells and immunohistochemical overexpression of MT was estimated for each case. Metallothionein overexpression, defined as those cases with more than 10% immunopositive cells, was detected in both benign and malignant mammary tumours. However, strong immunostaining intensity was seen in benign tumours, whereas in malignant tumours immunopositive cells stained weakly. Positive MT immunostaining occurred in neoplastic epithelial cells, and some chondrocytes present in mixed mammary tumours. I-Iowever, staining intensity was variable in immunopositive cells. Differences in staining intensity between the primary malignant mammary tumour, tumour emboli and metastatic cells within a lymph node were also noted. Myoepithelial cells and connective tissue did not stain for MT. We concluded that metallothionein immunostaining cannot be used as a diagnostic or prognostic tool in canine mammary neoplasms. However, results of this study support the hypothesis that MT has a role in tumour proliferation and tumour progression.
Open Access
Development of immune complex trapping: experimental study of lymphoid follicles and germinal centers newly induced by exogenous stimulants in mouse popliteal lymph nodes
(Murcia : F. Hernández, 1999) Horie, K.; Chen, D.; Hoshi, H.
The development of immune complex trapping in newly-induced lymphoid follicles of draining popliteal lymph nodes was investigated in young adult mice, which had been given bilateral injection of hemocyanin (KLH) or phytohemagglutinin (PHA), each absorbed onto alumina. HRP-anti-HRP immune complex was injected into the footpad 1 day before sacrifice. Using three series of semi-serial cryostat sections prepared from each popliteal node, the number of lymphoid follicles in each node was counted, and follicular localization of the in vivo injected and in vitro applied immune complexes in each follicle was determined. By day 5, a large germinal center had developed within each preexisting follicle. A large number of 'new' secondary follicles, each containing a small PNA-positive germinal center, appeared outside pre-existing follicles, from day 5 through day 11 in KLH-treated nodes, and from day 7 through day 14 in PHA-treated nodes. Shortly after their appearance, new secondary follicles showed no in vitro or in vivo trapping, but subsequently, many of the new follicles began to display in vitro trapping, at first weakly but later intensely. Occurrence of in vivo trapping in new follicles took some time and was first recognized when new follicles showed intense in vitro trapping. At day 21 or 25, many of the new follicles showed both in vitro and in vivo trapping. It was concluded that in lymph nodes treated with a stimulant, secondary follicles containing germinal centers can be formed de novo in the extrafollicular zone where the follicular trapping microenvironment is absent, but subsequently the microenvironment capable of trapping immune complexes develops at the site of formation of new follicles.
Open Access
Epigenetic modulation of differentiation in CE44 teratocarcinoma
(Murcia : F. Hernández, 1999) Álvarez, A.; Lacalle, J.; Garcia-Sanz, M.; Simón, J.; Aréchaga, J.; Hilario, E.
Teratocarcinoma is a mixed germ cell tumor histologically composed of embryonal carcinoma cells and embryonic and extraembryonic tissues. In the present work we have used the CE44 teratocarcinoma, which is a tumor cell line derived from the OTT6050 experimental tumor, to appreciate the influence the microenvironment has on the modulation of tumoral differentiation. For this, we have studied the development of CE44 teratocarcinoma in primary tumors (subcutaneous and intrasplenic) and in experimental metastases (hepatic and pulmonary). CE44 teratocarcinoma shows variations in its capacity for differentiation in so far as development is concerned and, in hepatic metastases, we noticed a reparative process of the intratumoral necrotic areas which in the same cases were substituted by loose connective tissue. Our results clearly suggest that the microenvironment is decisive in the biological behaviour of the teratocarcinoma cells and that epigenetic factors influence the capacity for differentiation of the undifferentiated tumoral cells.
Open Access
Clinical applications of detecting dysfunctional p53 tumor suppressor protein
(Murcia : F. Hernández, 1999) Baas, I.O.; Hruban, R.H.; Offerhaus, G.J.A.
The p53 gene encodes for a protein, p53, which plays a critical role in controlling the cell cycle, in DNA repair and in programed cell death (apoptosis). p53 is one of the most frequently mutated genes in human neoplasms and a variety of techniques have been developed to detect these mutations. These range from advanced molecular-genetic analyses to immunohistochemical staining for the p53 protein. This review will summarize our current understanding of the function of p53 as well as current methods to detect dysfunctional p53 and the clinical value of such analyses.
Open Access
Bcl-2 protein expression and gut neurohormonal polypeptidelamine production in colorectal carcinomas and tumor-neighboring mucosa, which closely correlate to the occurrence of tumor
(Murcia : F. Hernández, 1999) Ohmori, Takaaki; Asahi, S.; Sato, C.; Maki, F.; Masumoto, A.; Okada, K.
To clarify whether advanced colorectal carcinomas and tumor-neighboring mucosa simultaneously produce both Bcl-2 protein and gut neurohormonal polypeptides andlor amines, and the interrelationship of these phenomenon, we studied retrospective analysis of Bcl-2 protein production and neuroendocrine characteristics in 52 cases of advanced colorectal carcinoma and surrounding mucosa. All of the tumor-neighboring mucosa presented hyperplasia. The rates of enhanced immunoreactivity of the tumor-neighboring mucosa and of positive immunoreactivity of the carcinomas against human Bcl-2 protein and against human vasoactive intestinal polypeptide, pancreatic polypeptide and somatostatin were 78.8% and 94.2%, 82.7% and 59.6%, 78.8% and 67.3%, and 88.5% and 84.6% respectively. Double immunostaining for Bcl-2 protein and each peptide hormone revealed simultaneous expression. In contrast, that of tumor-neighboring mucosa and carcinomas to serotonin and chromogranin-A and to argyrophilia were 11.5% and 1.9%, 32.7% and 17.3%, and 26.9% and 21.2%, respectively. We concluded that tumor-neighboring crypt cells displayed not only hyperplasia but also neuroendocrine characteristics and that enhanced Bcl-2 protein immunoreactivity correlated with tumor occurrence in the wall of the colorectum. The production of Bcl-2 protein by tumor cells and tumorneighboring crypt cells indicates that the bcl-2 protooncogene may act not only as an inhibitor of apoptosis but also as an inducer of neuroendocrine differentiation from the latent characteristics of the endodermal stem cell.
Open Access
Molecular and cellular basis of tissue remodeling during amphibian metamorphosis
(Murcia : F. Hernández, 1999) Su, Y.; Damjanovski, S.; Shi, Y.; Shi, Y.B.
Amphibian metamorphosis involves systematic transformations of various tadpole organs1 tissues. Three major types of changes take place during this process. These are remodeling, resorption, and de novo development, all of which appear to involve both cell proliferation and apoptosis (programmed cell death). All metamorphic changes are controlled by thyroid hormone (T3) and are organ-autonomous. Recent studies using primary cell cultures and a stably transformed cell line from tadpole tissues have implicated that T3 induces apoptosis cell-autonomously. This T3-induced, metamorphosis-associated apoptosis is similar to cell death in other animal species and involves similar cell death executioners. Both the activation of these executioners and the pathways leading to cell proliferation and differentiation are believed to be through transcriptional regulation by T3 receptors (TRs). TRs can activate or repress target gene transcription depending upon the presence or absence of T3, respectively. Many direct T3-response genes have been isolated and found to encode a variety of proteins that can affect both intra- and extra-cellular events. The determinations of the identities of these response genes through sequence analyses and studies on their expression profiles during development have provided strong clues toward their roles in metamorphosis. However, future studies using organ and cell culture systems andlor transient or stable transgenic technologies are required to understand how these genes transduce the T3 signal to activate the downstream cell death and proliferation/differentiation pathways.
Open Access
Radial glia and cell debris removal during lesion-regeneration of the lizard medial cortex
(Murcia : F. Hernández, 1999) Nacher, J.; Ramirez, C.; Palop, J.J.; Molowny, A.; Luis de la Iglesia, J.A.; López-García, Carlos
Intraperitoneal injection of the neurotoxin 3- acetylpyridine (3AP) induces a rapid degeneration of the medial cerebral cortex (lizard fascia dentata) granular layer and of its zinc enriched axonal projection (lizard mossv fibres). After 6-8 weeks ~ost-lesionth e cell debris have ieen rekoved and the grakular layer is repopulated by neurons generated in the subjacent ependyma. Both processes, neuron incorporation and debris removal, seem to be crucial for successful regeneration. Scavenging processes in the lesioned mammalian CNS are usually carried out by microglia andlor astrocytes. In the lizard cerebral cortex there are no free astrocytes and the only glial fibrillary acid (GFAP) immunoreactive cells are radial glia-ependymocytes, similar to those present during mammalian CNS development. Ependymocytes, in addition to their help in vertical migrations of just generated immature neurons, built the cortical glial scaffold, insulate the blood capillaries, form the outer glial limiting membrane, thus playing an essential role in the lizard cortical blood-brain barrier. In this study, by means of GFAP-immunocytochemistry and electron microscopy, we have shown that radial glial cells participate actively in the removal/phagocytosis of cellular debris generated in the lesion process: mainly degenerated synapses, but interestingly, also some neuronal somata. Cell debris taken up by ependymocyte lateral processes seem to be progressively transported to either distal (pial) or proximal (ventricular) poles of the cell, where they result in lipofuscin accumulations. The hypothetical subsequent exchange of debris from ependymoglia by microglia/macrophages and Kolmer cells is discussed.
Open Access
Angiogenesis and expression of tenascin after transmural laser revascularization
(Murcia : F. Hernández, 1999) Gassler, N.; Rastar, F.; Hentz, M.W.
Transmyocardial revascularization (TMR) with CO2-laser equipment is an alternative approach in the treatment of patients with severe ischemic cardiac disease. Several studies concerning morphological features after TMR document a strong transmyocardial injury, but little is known about wound healing in laserinduced alterations of the cardiac skeleton and their putative role for angiogenesis and endothelialization. The present study was conducted to establish a useful immunohistochemical marker for detection of these laser-induced injuries and to analyze starting points of angiogenesis in human myocardium after TMR. Our data show that tenascin labeling is a useful immunohistochemical approach to detect laser-alterated segments of the cardiac skeleton as well as laser-induced fibrosis. Starting points of the angiogenetic process are seen throughout the margins of laser-induced lesions, where myocardial capillaries are found. Disrupted vessels located within laser-alterated connective tissue septa are not major starting points for endothelialization of laser-induced lesions and for capillary sprouts. In comparison to laser-induced fibrosis, induction and promotion of angiogenesis by laser radiation is weak.
Open Access
The use of the lectin Helixpomatia agglutinin (HPA) as a prognostic indicator and as a tool in cancer research
(Murcia : F. Hernández, 1999) Mitchell, B.S.; Schumacher, U.
Progress in treatment for cancer has enabled extension of the disease-free interval, and of the quality of life for patients, but there has been very little improvement in overall survival rates. The main reason for this has been the ineffectiveness of current therapies to kill all the cancer cells once they have spread to distant sites to form metastatic deposits. One marker which has proved to be useful in identifying those cancers which have the potential to spread is the lectin Helixpomatia agglutinin (HPA). In clinical studies, HPA binding to primary tumours in tissue sections has been of prognostic value in breast, colon and gastric cancer, while no prognostic significance for HPA could be detected in tumours of the head and neck. These studies hence indicate that HPA is best suited to recognise a glycotope on adenocarcinomas. In several studies, HPA reactivity is equal or superior to other classical markers of metastatic potential. Since HPA is a marker of prognosis at the level of individual tumour cells, human tumour cell lines were screened for their HPA positivity. When transplanted into severe combined immunodeficient (scid) mice, HPA positive human breast and colon cancer cells metastasised while HPA negative cancer cell lines in general did not. In order to define HPA binding glycotopes at the molecular level, isolated cell membrane glycoproteins were exposed to labelled HPA on nitrocellulose membranes after Western blotting procedure. The majority of the isolated cell membrane glycoproteins bound HPA indicating that not a single HPA binding glycoprotein exists, which is associated with the metastatic phenotype. Functional investigations using the humanlscid mouse chimeras will aid in the identification of those HPA positive glycoproteins which are functionally involved in the metastatic cascade.