Histology and histopathology Vol.20, nº 2 (2005)

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Open Access
Corneal endothelial cell density decreases with age in emmetropic eyes
(Murcia : F. Hernández, 2005) Sanchis-Gimeno, J.A.; Lleó-Pérez, A.; Alonso, L.M.; Rahhal, M.S.; Martínez Soriano, F.
Purpose: To analyze the corneal endothelial cell density in healthy adult emmetropic subjects. Methods: We analyzed the corneal endothelial cell density of a group made up of 225 emmetropic subjects (n=225). As age-matched control groups we analyzed two other groups, one made up of myopic subjects (n=209) and the other made up of hyperopic subjects (n=203). We recorded the mean of three consecutive measurements of the corneal endothelial cell density using the Topcon SP-2000P non-contact specular microscope (Topcon Corp., Tokyo, Japan). Results: The mean age was 38.6±11.8 years, 40.7±12.2 years, and 39.2±10.5 years for emmetropic, myopic and hyperopic subjects respectively (p=0.994). No significant differences (p=0.920) in endothelial cell density values were found between emmetropic (2985±245 cells/mm2), myopic (2936±258 cells/mm2) and hyperopic eyes (2946±253 cells/mm2). Lower corneal endothelial cell density values were found in older emmetropic (p<0.001), myopic (p<0.001), and hyperopic subjects (p<0.001). A significant correlation between endothelial cell density and age was found in emmetropic (r= -0.958; p<0.001), myopic (r= -0.954; p<0.001) and hyperopic subjects (r= -0.948; p<0.001). Conclusions: In healthy emmetropic subjects there is a reduction in corneal endothelial cell density with age although there are no differences in corneal endothelial cell density values between emmetropic, myopic and hyperopic subjects.
Open Access
Functional aspects of the somatostatinergic system in the retina and the potential therapeutic role of somatostatin in retinal disease
(Murcia : F. Hernández, 2005) Casini, G.; Catalani, E.; Dal Monte, M.; Bagnoli, P.
The somatostatinergic system of the retina has been investigated in a variety of studies. A considerable amount of experimental evidence is available concerning the patterns of expression of somatostatin (SRIF) and its receptors in vertebrate retinas. However the functional roles of this peptidergic system in retinal physiology are far from being elucidated. Nonetheless, data have been provided concerning the regulatory action of SRIF on the excitability of different retinal cell types and on the modulation of ion channels in different vertebrate retinas. The present review is focused on recent and unpublished investigations of the mouse retina relative to the involvement of specific SRIF receptors in the regulation of ion channels and transmitter release, the transduction pathways coupled to SRIF receptors, and the mechanisms regulating the expression of SRIF and its receptors as derived from studies in transgenic animal models. In these models, altered expression levels of SRIF or of specific SRIF receptors have also been found to affect the morphology of retinal cell types (namely the rod bipolar cells) and to result in functional alterations at the level of both ion channel regulation and transmitter release. These new pieces of evidence constitute an important step forward in the understanding of the functional actions of the retinal somatostatinergic system, although our current knowledge is far from being exhaustive. The ultimate goal of understanding SRIF functional actions in the retina is concerned with the possibility of using SRIF or its analogs as therapeutic agents to cure retinal diseases. Indeed, encouraging results are being obtained in clinical investigations focused on the use of SRIF analogs to treat diabetic retinopathy, a retinal disease with high social impact and originating as a complication of diabetes. The closing part of the present paper examines the evidence supporting SRIF as a promising therapeutic agent in this disease.
Open Access
Immunodetection of aldose reductase in normal and diseased human liver
(Murcia : F. Hernández, 2005) Brown, K.E.; Broadhurst, K.A.; Mathahs, M.M.; Kladney, R.D.; Fimmel, C.J.; Srivastava,S.K.; Brunt, E.M.
Aldose reductase is an NADPH-dependent aldo-keto reductase best known as the rate-limiting enzyme of the polyol pathway that is implicated in the complications of diabetes. Aldose reductase appears to be involved in a variety of disease states other than diabetes, presumably due to its ability to catalyze the reduction of a broad spectrum of aldehydes, including some cytotoxic products of lipid peroxidation. Although the data regarding expression of aldose reductase in normal liver are conflicting, prior studies have suggested that the enzyme may be induced in diseased liver. The goal of these studies was to characterize expression of aldose reductase in normal and diseased human liver, using RT-PCR, Western analysis and immunohistochemistry. Aldose reductase transcripts and protein were detected at low levels in control human livers. In contrast, levels of aldose reductase mRNA and protein were increased in chronically diseased human livers. Immunohistochemistry demonstrated localization of aldose reductase in sinusoidal lining cells; dual immunofluorescence confocal microscopy with the macrophage marker, CD68, confirmed that the aldose reductase-positive sinusoidal lining cells were Kupffer cells. Abundant aldose reductase-positive, CD68- positive cells were present in the fibrous septa of cirrhotic livers, accounting for the increase in Immunostaining of human lung, spleen and lymph node revealed that macrophages in those tissues also express aldose reductase. These data are the first to demonstrate that aldose reductase is expressed by human macrophages in various tissues and suggest that this enzyme may play a role in immune or inflammatory processes.
Open Access
Irradiation of the rabbit cornea with UVB rays stimulates the expression of nitric oxide synthases-generated nitric oxide and the formation of cytotoxic nitrogen-related oxidants
(Murcia : F. Hernández, 2005) Cejkova, J.; Ardan, T.; Cejka, C.; Kovaceva, J.; Zídek, Z.
Until now, the role of nitric oxide (NO) in cornea irradiated with UVB rays remains unknown. Therefore, we investigated nitric oxide synthase isomers (NOS), enzymes that generate NO, nitrotyrosine (NT), a cytotoxic byproduct of NO, and malondialdehyde (MDA), a byproduct of lipid peroxidation, in rabbit corneas repeatedly irradiated with UVB rays (312 nm, 1x daily for 6 days, the dose per day 1.01 J/cm2) using immunohistochemical methods. The biochemical measurement of nitrite and nitrate has been used for the indirect investigation of NO concentration in the aqueous humor. Results show that in contrast to normal corneas, where of the NOS isomers only endothelial nitric oxide synthase (NOS3) was expressed in a significant amount (in the epithelium and endothelium), in irradiated corneas all NOS isomers (also brain nitric oxide synthase, NOS1, and inducible nitric oxide synthase, NOS2) as well as an indirect measure of ONOO-formation and MDA were gradually expressed, first in the epithelium, the endothelium and the keratocytes beneath the epithelium and finally in the cells of all corneal layers and the inflammatory cells that invaded the corneal stroma. This was accompanied by an elevated concentration of NO in the aqueous humor. In conclusion, repeated irradiation with UVB rays evoked the stimulation of NO production, peroxynitrite formation (demonstrated by NT residues) and lipid peroxidation (evaluated by MDA staining).
Open Access
Morphological aspects of potassium flow in the semicircular canal ampulla of the pigeon
(Murcia : F. Hernández, 2005) Helling, K.; Merker, H. J.
Potassium ions are a prerequisite for the development and regulation of sensory cell stimulation in the inner ear. From the potassium-rich endolymph the ions flow into the sensory cells apically and are released basolaterally. After transport pathways of various lengths potassium is released again into the endolymph - in the cochlea by marginal cells of the stria vascularis, in the vestibular labyrinth by dark cells. While this long recycling pathway is relatively well-known in the cochlea, few studies have been conducted on the semicircular canal ampullae (SCCA) where its morphological basis is largely unknown. According to the present electron microscopic findings, potassium ions are initially released into the extracellular space during stimulation of the sensory cells and then absorbed by supporting and light cells. Finally they are transported transcellularly over numerous very long gap junctions into the region of the dark cells. From here they move to an extracellular compartment, which is more or less completely sealed off basally by basal plates of the light cells. Apically the intercellular space between light and dark cells is sealed by junctional complexes. This newly identified space in the SCCA corresponds to the extracellular compartment between the marginal and intermediate cells in the stria vascularis. At both sites, the cochlea and the SCCA, this probably serves as a regulatory valve, reservoir or storage space, particularly for potassium ions. It is likely that the different morphology of the ion transport pathways is related to the different flow levels of potassium ions expressed by the different levels of the so-called endocochlear potential and concomitant movement of other ions in the cochlea and SCCA.
Open Access
Administration of L-arginine reduces the delay of the healing process caused by ibuprofen. Implication of COX and growth factors expression
(Murcia : F. Hernández, 2005) Sánchez-Fidalgo, S.; Martín-Lacave, Inés; Illanes, M.; Bruseghini, L.; Esteras, A.; Motilva, V.
The objective of the present study has been to advance knowledge of the gastric role played by the amino acid L-Arginine (L-Arg) in the evolution of a chronic gastric ulcer. In order to clarify it, L-Arg alone or together with Ibuprofen have been administrated in an experimental acetic acid chronic ulcer, analysing characteristic parameters of an active curative process, such as PGE2 production, COX expression, and also angiogenesis, proliferation/apoptosis and growth factors expression. Our results reveal that L-Arg is favourable in the healing process improving the curative course. Ibuprofen caused a delay in ulcer healing, more evident 14 days after ulcer induction; COX-2 expression was increased at the 7th day although no signal of protein could be detected after 14 days; PGE2 production was inhibited in intact and ulcerated areas at both times assayed. In contrast, treatment with L-Arg reduced the delay of the lesion, the increment in COX-2 expression induced by Ibuprofen, and was able to maintain PGE2 levels similar to the control group after 14 days. Additionally, the histological study showed that the healing effects of L-Arg might be associated with an increased angiogenesis and FGF-2 expression. These actions could be considered key factors in the healing response associated with L-Arg administration. However, the proliferation study assayed with the PCNA-immunostaining method did not reveal significant differences, as the same as the apoptosis analysis. In conclusion, the coupling of L-Arg to Ibuprofen is an attractive alternative to Ibuprofen administration alone because it not only attenuates but also improves the evolution of chronic lesions through mechanisms that implicate endogenous PG and FGF-2- associated pathways, which allow an increase of angiogenesis process.
Open Access
Local immune response in serous papillary carcinoma of the endometrium
(Murcia : F. Hernández, 2005) Tamiolakis, D.; Venizelos, J.; Lambropoulou, M.; Nikolaidou, S.; Tsikouras, P.; Jivannakis, T.; Papadopoulos, N.
Objective: Serous papillary carcinomas of the endometrium are aggressive tumors that tend to permeate, in a very extensive fashion, to uterine and adnexal lymphatic and vascular channels at an early stage in their evolution, and are associated with a particularly gloomy prognosis. It is generally thought that even tumors apparently limited to the endometrium or confined to an endometrial polyp have a poor outcome. Our study points towards the value of HLADR antigen in the outcome of serous papillary endometrial cancer. Our aim was to assess the HLA-DR expression in inactive, endometrial intraepithelial carcinoma (EIC), and invasive serous carcinoma curretage specimens from the endometrial cavity, suggesting a role inimmune response to keep tumor proliferation in check. Study design: Thirty-one cases of inactive endometrium, twelve cases of EIC, and thirtynine cases of serous papillary invasive carcinoma curettings were evaluated for the detection of HLA-DR monoclonal antigen. T helper (TH) marker (CD4) in the tumor stroma of the relevant cases was also studied, given that it is now known that the dependence of immune responsiveness on the class II antigens reflects the central role of these molecules in presenting antigen to TH cells. Results: HLA-DR was expressed in 20 of 31 inactive endometrium (64.5%), 4 of 12 in EIC (33.3%), and in 10 of 39 serous papillary invasive carcinomas (25.6%). CD4 was expressed in 9 of 31 inactive endometrium (29%), 5 of 12 in EIC (42%), and in 26 of 39 serous papillary invasive carcinomas (67%). Conclusions: The results showed decreased expression of HLA-DR and increased expression of CD4 as the lesion progressed to malignancy. The aberrant expression of HLA-DR by epithelial cells of inactive endometrium, of EIC and of serous papillary invasive carcinomas agrees with the hypothesis of the inactive endometrium - carcinoma in situ sequence as the usual route for the development of serous papillary invasive carcinoma. The immune attract mechanism by low HLA-DR signaling seems to be of minor importance in the malignant and metastatic potential of the serous papillary endometrial tumours.
Open Access
Differential expression of tissue kallikrein in the skin of systemic sclerosis
(Murcia : F. Hernández, 2005) Milia, A.F.; Del Rosso, A.; Pacini, A.; Manetti, M.; Marrelli, A.; Nosi, Daniele; Giacomelli, R.; Matucci-Cerinic, M.; Ibba-Manneschi, L.
Systemic sclerosis (SSc) is characterised by ischemic damage, impaired angiogenesis and skin fibrosis. Tissue kallikrein (t-kallikrein) is involved through kinins in inflammation, vasorelaxation and angiogenesis. T-kallikrein is synthetised by endothelial, smooth muscle, and inflammatory cells and, in skin, also by dark cells of the sweat glands, where it is involved in sweat formation. Our aim was to analyse, by immunohistochemistry and RT-PCR, the expression of t-kallikrein in the skin of patients with different SSc subsets, limited (lSSc) and diffuse (dSSc), and phases, early and advanced. Skin biopsies were taken from 18 SSc patients and 10 controls. Immunohistochemistry was performed on paraffin sections with an antibody against human urinary t-kallikrein. For RT-PCR, cDNA from skin biopsies was amplified using primers specific for human t-kallikrein. In the control skin, dark cells of the secretory units of sweat glands showed immunopositivity for tkallikrein as well as blood vessels. In the lSSc skin, immunoreactivity was observed only in some glands, with weak staining in the advanced phase. In early lSSc skin, immunoreactivity was observed in microvessel walls and in the inflammatory infiltrate. In dSSc skin, dark cells of the glandular fundus units, and the few remaining vessels showed scarcity (early phase) or lack (advanced phase) of immunoreactivity for t-kallikrein. RT-PCR confirmed a decrease of t-kallikrein mRNA levels from early to advanced phase in SSc subsets, reaching its lowest level in advanced dSSc. In conclusion, immunohistochemical and biomolecular results indicate that t-kallikrein is decreased in the skin of SSc patients and decreases progressively from the early to advanced phase of lSSc and dSSc. The decreased expression of t-kallikrein may be involved in the impairment of the sweating process, vessel functionality and angiogenesis.
Open Access
Histological heterogeneity of human glioblastomas investigated with an unsupervised neural network (SOM)
(Murcia : F. Hernández, 2005) Iglesias-Rozas, J.R.; Hopf, N.
The histological variability of Glioblastomas (GB) precludes the modern assimilation of theses tumors into a single histological tumor group. As an alternative to statistical histological evaluation, we investigated 1489 human GB in order to discover whether they could be correctly classified using Self- Organizing Maps (SOM). In all tumors 50 histological features, as well as the age and sex of the patients, were examined. Four clusters of GB with a significance of 52 (maximal significance 60) were found. Cluster C1 contained 37.47% of all GB and 41.09% of all polymorphic glioblastomas (PG). Cluster C2 included 35.06% of all GB and 44.96% of all giant cell glioblastomas (GCG). Cluster C3 contained 16.45% of all GB with a significant component of astroblasts, glioblasts and oligodendroglia. Cluster C4 included 11.01% of all GB, 87.80% of the gliosarcomas (GS) and 36.72% of all GCG. Placing a series of component windows with their maps side by side allows the immediate recognition of the dependencies on variables and the determination of variables necessary to build the specific clusters. The SOM allow a realistic histological classification, comparable to the actual classification by the WHO. In addition, we found new, small subclusters of human GB which may have a clinical significance. With SOM one can learn to discriminate, discard and delete data, select histological and clinical or genetic variables that are meaningful, and consequently influence the result of patient management.
Open Access
Photopigment coexpression in mammals: comparative and developmental aspects
(Murcia : F. Hernández, 2005) Lukáts, A.; Szabó, A.; Röhlich, P.; Vígh, B.; Szél, A.
In mammals, each cone had been thought to contain only one single type of photopigment. It was not until the early 1990s that photopigment coexpression was reported. In the house mouse, the distribution of color cones shows a characteristic division. Whereas in the upper retinal field the ratio of short wave to middleto- long wave cones falls in the usual range (1:10), in the ventral retinal field M/L-pigment expression is completely missing. In the transitional zone, numerous dual cones are detectable (spatial coexpression). In other species without retinal division, dual cones appear during development, suggesting that M/L-cones develop from S-cones. Dual elements represent a transitory stage in M/L-cone differentiation that disappear with maturation (transitory coexpression). These two phenomena seem to be mutually exclusive in the species studied so far. In the comparative part of this report the retinal cone distribution of eight rodent species is reported. In two species dual cones appear in adult specimens without retinal division, and dual elements either occupy the dorsal peripheral retina, or make up the entire cone population. This is the first observation proving that all cones of a retina are of dual nature. These species are good models for the study of molecular control of opsin expression and renders them suitable sources of dual cones for investigations on the role and neural connections of this peculiar cone type. In the developmental part, the retinal maturation of other species is examined to test the hypothesis of transitory coexpression. In these species S-pigment expression precedes that of the M/L-pigment, but dual cones are either identified in a small number or they are completely missing from the developing retina. These results exclude a common mechanism for M/L-cone maturation: they either transdifferentiate from S-cones or develop independently.
Open Access
Bioactive lysophospholipids and mesangial cell intracellular signaling pathways: role in the pathobiology of kidney disease
(Murcia : F. Hernández, 2005) Kamanna, V.S.; Bassa, B.V.; Ganji, S.H.; Roh, D.D.
Lysophosphatidic acid (LPA), lysophosphatidylcholine (LPC), and sphingosine -1- phosphate (S1P) are major biologically active lysophospholipids (LPLs) that are produced by activated platelets, monocyte/macrophages, and many types of mammalian cells. LPLs have been shown to induce a wide array of physiological and pathophysiological properties including cellular differentiation, proliferation, migration, extracellular matrix deposition, change in morphology, and chemotactic responses. The recent cloning and identification of G protein-coupled receptors as specific receptors for LPLs created a great deal of interest in LPLs signaling and diverse biological responses. The pathobiological role of LPLs has been implicated in a number of pathological states and human diseases including atherosclerosis, glomerulosclerosis, post-ischemic renal failure, polycystic kidney disease, and ovarian cancer. Although the research in this area is growing at an enormous rate, this review is specifically focused on the recent understanding of the pathophysiological properties of LPA and LPC with special reference to kidney diseases, and their specific G-protein-coupled receptors and intracellular signaling pathways.
Open Access
Effects of single, double or triple combinations of octreotide, galanin and serotonin on a human pancreatic cancer cell line
(Murcia : F. Hernández, 2005) Tjomsland, V.; El-Salhy, M.
The human pancreatic cancer cell line (SW 1990) was exposed to 0.2 µg/ml of octreotide, galanin or serotonin as single, double or triple combinations. The tumor cells were checked at 3, 6 and 12 hours. In order to determine the number of viable cancer cells, the MTTassay was used. Proliferation, apoptosis and the expression of epidermal growth factor were detected with immunohistochemistry using the avidin-biotin complex method. In addition, apoptosis was also detected with (TUNEL) method. The primary antibodies used were proliferating cell nuclear antigen (PCNA), anti-poly (ADP-ribose) polymerase (PARP) and antihuman epidermal growth factor. Single treatment with octreotide or serotonin reduced, the number of viable cells and the proliferation index at all observation times. Galanin increased the number of viable cells and the proliferation index. Whereas double treatments containing octreotide reduced the number of viable cells, those containing galanin increased the number. The effect of single, double or triple treatment on the apoptotic index obtained with both TUNEL method and PARP expression varied depending on the combination and the observation time. Octreotide did not affect the tumor cell expression of EGF. Galanin and serotonin, on the other hand, increased the expression of EGF Whereas triple combination increased the expression of EGF after 6 h, all the other double combinations decreased this expression. It has been concluded that treatment with a combination of octreotide and serotonin may be useful in clinical settings.
Open Access
Human and animal spongiform encephalopathies are the result of chronic autoimmune attack in the CNS: A novel medical theory supported by overwhelming experimental evidence
(Murcia : F. Hernández, 2005) Ting Zhu, Bao
Spongiform encephalopathies, also called "prion diseases", are fatal degenerative diseases of the central nervous system which can occur in animals (such as the "mad cow disease" in cattle) and also in humans. This paper presents a novel medical theory concerning the pathogenic mechanisms for various human and animal spongiform encephalopathies. It is hypothesized that various forms of prion diseases are essentially autoimmune diseases, resulting from chronic autoimmune attack of the central nervous system. A key step in the pathogenic process leading towards the development of spongiform encephalopathies involves the production of specific autoimmune antibodies against the disease-causing prion protein (PrPsc) and possibly other immunogenic macromolecules present in the brain. As precisely explained in this paper, the autoimmune antibodies produced against PrPsc are responsible for the conversion of the normal cellular prion protein (PrPc) to PrPsc, for the accumulation of PrPsc in the brain and other peripheral tissues, and also for the initiation of an antibody-mediated chronic autoimmune attack of the central nervous system neurons, which would contribute to the development of characteristic pathological changes and clinical symptoms associated with spongiform encephalopathies. The validity and correctness of the proposed theory is supported by an overwhelming body of experimental observations that are scattered in the biomedical literature. In addition, the theory also offers practical new strategies for early diagnosis, treatment, and prevention of various human and animal prion diseases.
Open Access
Microtubules regulate aortic endothelial cell actin microfilament reorganization in intact and repairing monolayers
(Murcia : F. Hernández, 2005) Lee, J.S.Y.; Gotlieb, A.I.
To understand the role of microtubules and microfilaments in regulating endothelial monolayer integrity and repair, and since microtubules and microfilaments show some co-alignment in endothelial cells, we tested the hypothesis that microtubules organize microfilament distribution. Disruption of microtubules with colchicine in resting confluent aortic endothelial monolayers resulted in disruption of microfilament distribution with a loss of dense peripheral bands, an increase in actin microfilament bundles, and an associated increase of focal adhesion proteins at the periphery of the cells. However, when microfilaments were disrupted with cytochalasin B, microtubule distribution did not change. During the early stages of wound repair of aortic endothelial monolayers, microtubules and microfilaments undergo a sequential series of changes in distribution prior to cell migration. They are initially distributed randomly relative to the wound edge, then align parallel to the wound edge and then elongate perpendicular to the wound edge. When microtubules in wounded cultures were disrupted, dense peripheral bands and lamellipodia formation were lost with increases in central stress fibers. However, following microfilament disruption, microtubule redistribution was not disrupted and the microtubules elongated perpendicular to the wound edge similar to non-treated cultures. Microtubules may organize independently of microfilaments while microfilaments require microtubules to maintain normal organization in confluent and repairing aortic endothelial monolayers.
Open Access
Impairment of thrombospondin-1 expression during epithelial wound healing in corneas of vitamin A-deficient mice
(Murcia : F. Hernández, 2005) Uno, K.; Kuroki, M.; Hayashi, H.; Uchida, H.; Oshima, K.
The purpose of this study is to investigate the expression of thrombospondin-1 (TSP-1), a multifunctional extracellular matrix protein, during reepithelialization in wounded corneas of vitamin Adeficient mice. Epithelial defects were created in the corneas of normal and Vitamin A-deficient mice with a microgrinder. Wounded corneas were stained with fluorescein and photographed for evaluation of reepithelialization. Histological examination and immunohistochemical analysis of TSP-1 expression were also performed on the specimens from wounded corneas. In vitamin A-deficient mice, re-epithelialization of the wounded corneal epithelium was significantly delayed compared with that in normal mice. TSP-1 was detectable neither in the unwounded corneal epithelium of normal mice nor in that of vitamin A-deficient mice. In normal mice, linear staining of TSP-1 was observed on the wounded corneal surface and stroma at 30 min and 8 h to 16 h, respectively, after abrasion, and this TSP-1 expression disappeared at 36 to 48 h, when reepithelialization was completed. In contrast, no TSP-1 staining was observed in the wounded corneas of vitamin A-deficient mice, except for the endothelial cells, throughout the wound healing process. Histological examination revealed a progressive increase in polymorphonuclear neutrophil infiltration in the stroma of the corneas of vitamin A-deficient mice during the healing process. These findings suggest that vitamin A may modulate the expression of TSP-1 in the corneas to accelerate the re-epithelialization of wounded corneas.
Open Access
Dose-dependent promoting effect of dextran sodium sulfate on mouse colon carcinogenesis initiated with azoxymethane
(Murcia : F. Hernández, 2005) Suzuki, R.; Kohno, H.; Sugie, S.; Tanaka, T.
We previously reported a powerful tumorpromoting ability of dextran sodium sulfate (DSS) in a novel mouse model for colitis-related colon carcinogenesis initiated with azoxymethane (AOM). To determine the dose-dependent influence of DSS in our animal model, male ICR mice were given a single intraperitoneal injection of AOM (10 mg/kg body weight), followed by DSS at dose levels of 2, 1, 0.5, 0.25, and 0.1% (w/v) in drinking water for 1 week. All animals were sacrificed at week 14 and histological alterations in their colon and nitrotyrosine immunohistochemistry were examined to evaluate the nitrosative stress. In the mice which received AOM and 2% DSS, the incidences (multiplicity) of colonic tubular adenoma and adenocarcinoma were 75% (1.25±1.26/mouse) and 100% (2.75±2.22/mouse), respectively. Mice given AOM and 1% DSS had 80% incidence of adenoma (1.00±0.71/mouse) and 60% incidence of adenocarcinoma (1.40±2.07/mouse) in the colon. In a mouse treated with AOM and 0.5% DSS, only one colonic adenoma (20% incidence with 0.20±0.45 multiplicity) developed. Higher frequency of high-grade colonic dysplasia was noted in mice given AOM and 2% or 1% DSS when compared with mice treated with AOM and lower doses of DSS. Also, scoring of inflammation and nitrotyrosine immunoreactivity suggested that severe inflammation and nitrosation stress caused by high-doses (2% and 1%) of DSS contribute its tumor-promoting effects in mouse colon carcinogenesis initiated with a low dose of AOM. Thus, our findings indicate that a tumor-promoting effect of DSS was dose-dependent (1% or more) and the effect might occur under the condition of inflammation and nitrosation stress.
Open Access
Immunohistochemical localization of phosphatidylcholine in rat mandibular condylar surface and lower joint cavity by cryotechniques
(Murcia : F. Hernández, 2005) Zea-Aragón, Z.; Terada, N.; Ohtsuki, K.; Ohnishi, M.; Ohno, S.
The immunolocalization of phospholipids has not yet been clearly demonstrated in temporomandibular joints (TMJs). We have examined the distribution of one of phospholipids, phosphatidylcholine (PC), in the rat mandibular condylar surface and lower joint cavity. Some fresh resected TMJs with their disks attached were immediately plunged into isopentane-propane cryogen (-193 °C). Cryostat sections were cut, mounted on NH3 +-coated slides, and fixed with paraformaldehyde (PF). Cryosections were first immunostained with anti-mouse PC antibody (JE-1). Subsequently, they were labeled with immunogold particles following silver enhancing for light microscopic analyses. Some cryosections were subjected to double immunofluoresecence labeling with antifibronectin antibody or hyaluronic acid-binding protein in combination with the anti-PC antibody. As an immunocontrol, other cryosections were pretreated with phospholipase A2 before such immunofluorescence labeling. We have confirmed the presence of PC in the lower joint cavity of rat TMJs as well as on the mandibular condylar surface layer, which was colocalized with hyaluronic acid and fibronectin respectively. However, by treatment with phospholipase A2, such immunolabeling for PC was clearly decreased, showing that the PC is a component in the rat in vivo TMJ. These findings suggest that PC, hyaluronic acid and fibronectin may interact each other in the TMJ articular surface areas to play a functional role for lubrication in TMJ.
Open Access
Characterization of metaplastic and heterotopic epithelia in the human gastrointestinal tract by the expression pattern of acyl-CoA synthetase 5
(Murcia : F. Hernández, 2005) Gassler, N.; Obermüller, N.; Keith, M.; Schirmacher, P.; Autschbachl, F.
Metaplastic and heterotopic epithelia are frequently found in the human intestine. The recently cloned human acyl-CoA synthetase 5 (ACS5) is a key enzyme in providing cytosolic acyl-CoA thioesters. The aim of the study was to identify and to locate the expression of ACS5 in the gastric body and the small intestine with metaplasia or heterotopia by different methods. In the normal gastrointestinal tract, ACS5 was predominantly found in the villus epithelium of the small intestine, but not in the gastric mucosa. Of note, strong expression of ACS5 was also detectable in intestinal metaplasia of the stomach. Inversely, ACS5 expression could neither be detected in heterotopic gastric mucosa of the corpus type nor in gastric, pseudopyloric, or antral metaplasia of the small intestine. In conclusion, our data implicate that ACS5 is a suitable differentiating marker molecule in the gastrointestinal tract.
Open Access
The signaling network of tumor invasion
(Murcia : F. Hernández, 2005) Wang, G.K.; Zhang, W.
The ability of a cell to invade its surroundings is an important hallmark of malignant tumors and results from aberrant cell signaling mechanisms. The signal transduction that leads to tumor invasion can be broken down into major pathways. Even though the pathway systems are distinct in themselves, none of these pathways operate independently when it comes to transmitting signals that culminate in an invasive phenotype. That is, the malignant change in one receptor not only leads to malignant changes directly downstream but can also affect the molecules of many other pathways. Three major pathway systems involved in tumor invasion are discussed in this review: the integrin system, the insulin-like growth factor system, and the Rho family GTPases. Here we see that although the individual signaling systems can each contribute to invasion, each system is networked to others and should not be considered isolated. Each system is first reviewed as independent contributors to an invasive phenotype and then discussed in the context of interacting pathways that collectively result in tumor invasion.
Open Access
The tumor suppressor RASSF1A in human carcinogenesis: an update
(Murcia : F. Hernández, 2005) Dammann, R.; Schagdarsurengin, U.; Seidel, C.; Strunnikova, M.; Rastetter, M.; Baier, K.; Pfeifer, G.P.
Loss of heterozygosity of the small arm of chromosome 3 is one of the most common alterations in human cancer. Most notably, a segment in 3p21.3 is frequently lost in lung cancer and several other carcinomas. We and others have identified a novel Ras effector at this segment, which was termed Ras Association Domain family 1 (RASSF1A) gene. RASSF1 consists of two main variants (RASSF1A and RASSF1C), which are transcribed from distinct CpG island promoters. Aberrant methylation of the RASSF1A promoter region is one of the most frequent epigenetic inactivation events detected in human cancer and leads to silencing of RASSF1A. Hypermethylation of RASSF1A was commonly observed in primary tumors including lung, breast, pancreas, kidney, liver, cervix, nasopharyngeal, prostate, thyroid and other cancers. Moreover, RASSF1A methylation was frequently detected in body fluids including blood, urine, nipple aspirates, sputum and bronchial alveolar lavages. Inactivation of RASSF1A was associated with an advanced tumor stage (e.g. bladder, brain, prostate, gastric tumors) and poor prognosis (e.g. lung, sarcoma and breast cancer). Detection of aberrant RASSF1A methylation may serve as a diagnostic and prognostic marker. The functional analyses of RASSF1A reveal an involvement in apoptotic signaling, microtubule stabilization and mitotic progression. The tumor suppressor RASSF1A may act as a negative Ras effector inhibiting cell growth and inducing cell death. Thus, RASSF1A may represent an epigenetically inactivated bona fide tumor suppressor in human carcinogenesis.