J García-Valero

University of Barcelona, Barcelona, Catalonia, Spain

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Publications (22)82.59 Total impact

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    ABSTRACT: Among all inflammatory cells involved in COPD, those with a cytolytic or elastolytic activity are thought to play a key role in the pathogenesis of the disease. However, there is no data about the infiltration of cells expressing the CD57 marker in small airways and parenchyma of COPD patients. In this study, surgical specimens from 43 subjects undergoing lung resection due to lung cancer (9 non-smokers, 18 smokers without COPD and 16 smokers with moderate COPD) and 16 patients undergoing double lung transplantation for very severe COPD were examined. CD57+ cells, neutrophils, macrophages and mast cells infiltrating bronchioles (epithelium, smooth muscle and connective tissue) and parenchymal interstitium were localized and quantified by immunohistochemical analysis. Compared to the other groups, the small airways of very severe COPD patients showed a significantly higher density of CD57+ cells, mainly infiltrated in the connective tissue (p=0.001), and a significantly higher density of neutrophils located characteristically in the epithelium (p=0.037). Also, the density of neutrophils was significantly higher in parenchyma of very severe COPD patients compared with the rest of the groups (p=0.001). Finally, there were significant correlations between the bronchiolar density of CD57+ cells and the FEV1 values (R=-0.43, p=0.022), as well as between the parenchymal density of neutrophils and macroscopic emphysema degree (R=0.43, p=0.048) in COPD groups. These results show that CD57+ cells may be involved in COPD pathogenesis, especially in the most severe stages of the disease.
    Histology and histopathology 01/2012; 27(1):39-47. · 2.28 Impact Factor
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    ABSTRACT: Although the presence of pulmonary lymphoid follicles (LFs) has been associated with the progression of chronic obstructive pulmonary disease (COPD), there is no information regarding the pattern of vascularisation, expression of addressins or inflammatory cell densities within these structures in COPD. Histological and immunohistochemical techniques were used to assess the prevalence, structure, localisation, vascularisation and cell proliferation/apoptosis of LFs, as well as the follicular density of B- and T-lymphocytes, macrophages, dendritic cells and CD57(+) cells, in lung tissue of nine nonsmokers, 18 smokers without COPD, 16 smokers with moderate COPD and 16 patients with very severe COPD. The density of CD57(+) cells within LFs of COPD patients was significantly increased compared to that of nonsmokers and smokers without COPD (p<0.05). Moreover, the percentage of LF profiles with cell apoptosis was also significantly higher in COPD patients (p = 0.03). By contrast, no significant differences among groups were observed in the follicular densities of other inflammatory cells, nor in the distribution of blood and lymphatic vessels within LFs. Since CD57(+) cells are important effectors of cytotoxicity and immune regulation, an increase in their follicular density supports the hypothesis of local immune dysfunction in COPD.
    European Respiratory Journal 02/2011; 37(2):289-98. · 6.36 Impact Factor
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    ABSTRACT: In COPD, although histological lesions at both the small airways (wall thickening and tissue remodeling) and lung parenchyma (emphysematous destruction) are definitely different, the inflammatory cells involved in both processes are the same. Our study aims to determine if these histopathological phenotypes are related to two different lymphocyte profiles. Distribution and cell density of CD3(+), CD4(+), CD8(+) and B lymphocytes were compared in small airways and parenchymal interstitium of 9 non-smokers, 18 smokers without COPD, 16 smokers with moderate COPD and 16 patients with very severe COPD undergoing lung transplantation. Spatial distribution of lymphocytes in periemphysematous parenchyma was also assessed. CD3(+) and B cell densities were significantly higher in small airways than parenchyma interstitium of very severe COPD patients. Furthermore, CD8(+) cells were increased in the epithelium of airways of moderate COPD patients compared to non-smokers. Although CD8(+) cell density was increased in parenchyma of COPD patients, CD8(+) and B cell densities were similar when comparing periemphysematous and non-emphysematous alveolar interstitium. In COPD, it is true that the small airways' wall shows a clear inflammatory pattern, with a high mononuclear infiltration and tissue remodeling. However, parenchymal interstitium shows a milder CD8(+) infiltration which, moreover, is not spatially related to emphysematous destroyed areas.
    Respiratory medicine 03/2010; 104(9):1310-8. · 2.33 Impact Factor
  • Juan F Montes, José García-Valero, Jaume Ferrer
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    ABSTRACT: To conduct a detailed morphologic and ultrastructural study of pleural adhesions following talc pleurodesis. Talc with a main particle size of 8.36 +/- 0.2 mum (mean +/- SEM) and at a dose of 200 mg/kg in a 2-mL slurry was instilled via a small catheter into the pleural cavity of 10 male rabbits. Five rabbits were killed at 1 week, and five rabbits were killed at 1 month after instillation. At autopsy, after macroscopically observing the pleural cavity, adhesions were excised from opposing pleural surfaces and processed for histopathologic, immunocytochemical, and ultrastructural study. At 1 week, all adhesions examined were mesothelium-covered fibrovascular bands containing well-developed blood and lymphatic vessels establishing a structural continuity between both pleural layers. Nerves were present in adhesions from 20% of the rabbits. They consisted of a single fascicle containing 5 to 20 thin myelinated axons of various diameters (1 to 6 microm) uniformly distributed throughout the nerve section. The anatomic location of the adhesion did not appear to influence its overall morphology. As early as at 1 week, adhesions are well-formed structures more resembling newly formed pleural tissue than a simple scar. Nerve fibers in pleural adhesions are reported for the first time, which suggests that these adhesions are potentially capable of conducting pain stimuli. Further studies are required in order to confirm our results in human pleural adhesions.
    Chest 10/2006; 130(3):702-9. · 5.85 Impact Factor
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    Juan F Montes, Mercè Durfort, José García-Valero
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    ABSTRACT: Trophozoite, prezoosporangium and zoospore are the 3 main developmental stages that form the life cycle of protozoa of the genus Perkinsus. Several studies have shown that the differentiation of Perkinsus species from the trophozoite to the prezoosporangium stage involves a substantial modification of the antigenic characteristics of these molluscan parasites. With the aim of determining the presence and distribution of antigenic determinants conserved during trophozoite to prezoosporangium differentiation, a polyclonal serum was raised against trophozoites of P. atlanticus purified from parasitized gills of the clam Tapes semidecussatus. Immunocytochemical analyses showed that the serum generated against P. atlanticus trophozoites strongly cross-reacted with the prezoosporangium stage. Immunogold electron microscopy studies revealed that the granular component of the nucleolus, chromatin, cell wall, plasmalemma, lomasomes and vacuolar membrane are the main subcellular structures where the immunodominant epitopes consistently expressed by trophozoites and prezoosporangia are located. Furthermore, analysis of the immunogold staining pattern revealed that the labelling density obtained for prezoosporangia in the nucleolus, cell wall, plasmalemma and lomasomes was significantly higher than that obtained for trophozoites. The most immunoreactive structure in trophozoites was the granular component of the nucleolus, whereas in prezoosporangia it was the lomasome. Interestingly, the main antigenic compartment of P. atlanticus, considering both developmental stages, was the lomasome of the prezoosporangium. These findings show that P. atlanticus trophozoite to prezoosporangium differentiation is accompanied by significant qualitative and quantitative changes in the ultrastructural distribution of the immunodominant antigens shared by these 2 developmental stages.
    Diseases of Aquatic Organisms 09/2005; 66(1):33-40. · 1.73 Impact Factor
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    ABSTRACT: This study was designed to ascertain, in a rabbit model, extrapleural talc deposition and the related inflammatory response after talc slurry pleurodesis with two clinical doses, 200 and 50 mg/kg. Histopathologic evaluations revealed that whereas numerous rabbits receiving a high dose had talc in the ipsilateral (70%) and contralateral (55%) lung, mediastinum (90%), pericardium (30%), and liver (25%), a small number of animals treated with a low dose showed talc in the ipsilateral lung (10%) and mediastinum (20%) and none in the contralateral lung, pericardium, or liver. Hematologic and immunocytochemical analyses showed that a systemic inflammatory response develops shortly after pleurodesis with a high talc dose involving massive accumulation of neutrophils and macrophages in lung tissue. Zymography also revealed that the pulmonary expression of matrix metalloproteinases 2 and 9 was up-regulated in both lungs in a dose-dependent manner soon after talc instillation. Furthermore, microscopic examination of lung specimens revealed that the higher the dose of talc, the greater the development of both fibrotic visceral pleural thickening and foreign-body granulomas. These findings show pleurodesis with a high talc dose to be associated with an increased risk of extrapleural talc deposition, which may originate undesirable acute and chronic inflammatory responses.
    American Journal of Respiratory and Critical Care Medicine 09/2003; 168(3):348-55. · 11.04 Impact Factor
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    ABSTRACT: Cases of acute respiratory failure reported after talc pleurodesis have raised concerns about its safety. It has been speculated that this pulmonary inflammatory syndrome is secondary to the extrapleural dissemination of the talc particles. To test the hypothesis that particle size influences extrapleural talc deposition and pleural inflammation after talc slurry pleurodesis. Thirty rabbits underwent pleurodesis as follows: 10 rabbits received 200 mg/kg of the talc used for human pleurodesis, normal talc (NT); 10 rabbits received 200 mg/kg of talc with particles of larger size, large talc (LT); and 10 rabbits received saline solution. Samples from the ipsilateral lung, chest wall, diaphragm, mediastinal pleura, heart, liver, spleen, and right kidney were obtained at 24 h and 7 days and processed for optic and electron microscopy and energy-dispersive x-ray analysis. Visceral pleural thickening was greater with NT than with LT, but no differences were observed in the macroscopic score of adhesions. There was more talc in the lungs of the rabbits that received NT than in those that received LT. Talc particles were detected in mediastinum (100%) and pericardium (20%), irrespective of the talc used. Three animals, all receiving NT, had talc particles in the liver. Our study shows that while both talcs were equally effective in achieving pleurodesis, the intrapleural injection of NT elicits greater pulmonary and systemic talc particle deposition than LT. Moreover, pleural inflammation was greater with NT than with LT.
    Chest 10/2002; 122(3):1018-27. · 5.85 Impact Factor
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    ABSTRACT: Amyloidosis is a highly prevalent disease characterized by the deposition of amyloid fibrils. Although several types of amyloidosis can be identified according to their protein constituents and suggest putative aetiological factors, the causes of amyloidosis remain unknown. Furthermore, the cellular participation and the ultrastructural particularities of amyloidosis have received little attention. The aim of our study was to evaluate the vascular participation in amyloidosis and the cellular consequences of this disease. Two forms of amyloidosis were studied: experimental amyloid A (AA) and clinical beta(2)-microglobulin amyloidosis. We studied kidney, liver, and spleen in a mouse model, and examined surgically obtained carpal deposits from dialysis patients. We used light and electron microscopy with immunogold labelling for anti-beta(2)-microglobulin and anti-AA protein antibodies. AA amyloid fibril accumulation was associated with membrane lesions in basal, cytoplasmic organelle (endoplasmic reticulum, mitochondria), and nuclear membranes. Amyloid fibrils from beta(2)-microglobulin amyloidosis were also closely associated with elastic fibres and endothelial basement membrane. We observed proliferation of endothelial cells as well as basement membrane enlargement and disruption. Vascular abnormalities, including endothelial enlargement, basement membrane modifications, and vascular proliferation were associated with amyloidosis. Amyloid fibrils have a high avidity for elastic fibres and are able to contact and damage the basement membrane, the cell and intracellular organelle membranes, as well as the nuclear envelope, suggesting a toxic effect of amyloid fibrils on cells.
    Nephrology Dialysis Transplantation 09/2002; 17(8):1450-6. · 3.37 Impact Factor
  • J F Montes, M Durfort, A Lladó, J García-Valero
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    ABSTRACT: Described in the present study is a major component of the cell wall of 2 of the most pathogenic parasites of molluscs, Perkinsus atlanticus and P. marinus. The component is a high molecular weight protein (233 kDa), which we have named PWP-1 (for Perkinsus wall protein-1). Western blots, using a polyclonal serum generated against purified PWP-1 from P. atlanticus, revealed that this protein is expressed by all walled developmental stages of this protozoon. By means of immunogold electron microscopy, labelling for PWP-1 was strong and specifically associated with the cell wall. The label density and distribution pattern was quite different between trophozoites and prezoosporangia. With regard to the structural organization of this protein, PWP-1 is disulphide-linked to other cell wall components and released from the cell wall only following treatment with a sulphydryl agent. We also report that PWP-1 is a trypsin-resistant protein, both in its native and heat-denatured conformation. In addition, results from the N-terminal microsequence of this protein allow us to define PWP-1 as a novel cell wall protein. Overall, our findings strongly suggest that PWP-1 plays a key role in the organization of the cell wall of these protozoa, promoting their survival.
    Parasitology 06/2002; 124(Pt 5):477-84. · 2.36 Impact Factor
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    J F Montes, M Durfort, J García-Valero
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    ABSTRACT: It has been suggested that opportunistic pathogens could contribute to the mortality of Perkinsus atlanticus-infected clams. Examination of Tapes semidecussatus clams from the northern Mediterranean coast of Spain revealed that while 86% of the clams heavily infected with P. atlanticus were co-infected by bacteria and/or viruses, neither non-infected nor lightly P. atlanticus-infected specimens had bacterial or viral infections. The bacteria, which had a Gram-negative cell wall, were always located in the apical pole of gill epithelial cells and enclosed within membranous compartments. Bacteria-containing cells were hypertrophied and showed dysplasia with loss of cilia and microvilli. The viruses shared ultrastructural, morphologic and cytopathic characteristics of a polyomavirus. Viral particles with icosahedral symmetry were found in both the cytoplasm and the nucleus of numerous cell types. Virus-infected cells showed severe alterations, including hypertrophy, reduction of the intracellular compartments and extrusion of the nuclear envelope. Moreover, gill epithelial cells showed disorganization and swelling of the apical region, which affected the ciliary structure. Our findings show that P. atlanticus parasitism favours the development of opportunistic infections which have detrimental effects in this clam population.
    Diseases of Aquatic Organisms 09/2001; 46(1):57-66. · 1.73 Impact Factor
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    ABSTRACT: An image analysis strategy was designed to objectively determine distribution patterns of cell types in spleen sections. The strategy was applied to rat spleen cryostat sections that were strained immunohistochemically by means of monoclonal antibodies against different populations of lymphocytes and macrophages. The strategy revealed three segments of the spleen beginning in the middle of a central arteriole and ending within the red pulp. In each of these segments, three consecutive zones were established: the white pulp, the marginal zone, and the red pulp. In each tissue section, three segments were selected starting in two different arterioles. Consequently, six segments were analysed in each section. Special software was used to calculate percentages of positive staining in all zones in each segment. Image analysis data for each monoclonal antibody tested correlated closely with microscopical observations. The proposed strategy allows objective quantification of lymphocyte and macrophage populations and their distribution patterns. It is an useful tool for studying imbalances in cell populations in the spleen due to immune challenges.
    Acta Histochemica 08/1999; 101(3):281-91. · 1.61 Impact Factor
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    ABSTRACT: Macrophages may participate in amyloid fibril formation by processing the protein precursor. Although this theory seems to apply for amyloidosis, in which proteolytic cleavage is a prerequisite for amyloid fibril formation, it has not been demonstrated for beta2-microglobulin (beta2m) amyloidosis. We aimed to establish the role played by macrophages in beta2m amyloidosis. We used a double immunogold electron microscopy technique, including mouse antihuman CD68, rabbit antihuman beta2m, amyloid P component, and lysosome-associated membrane protein (LAMP-1) antibodies. Differential density labeling studies of beta2m and amyloid P component were performed extra- and intracellularly to assess protein processing by macrophages. The cells surrounding amyloid fibrils were found to be mostly CD68 positive, suggesting that they were of monocyte-macrophage lineage. Intracellular accumulation of amyloid fibrils was also observed; these fibrils were constantly surrounded by LAMP-1-linked gold particles, demonstrating that intracellular beta2m was almost exclusively lysosomal. The rough-surface endoplasmic reticulum was not labeled by beta2m antibody, suggesting that there was no active synthesis of beta2m by the cells. As a marker of endocytosis, protruded cytoplasmic processes in close relation with the intracellular accumulations of beta2m amyloid fibrils were observed. No difference in density labeling (extracellular vs. intracellular) was observed for beta2m, whereas intracellular P component labeling was significantly decreased. All of these data are strongly suggestive of phagocytosis and not synthesis of amyloid fibrils by macrophages. Further, they demonstrate an impaired lysosomal processing specific for beta2m, as other compounds of the amyloid fibrils (P component) are significantly cleared.
    Kidney International 04/1999; 55(3):899-906. · 8.52 Impact Factor
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    ABSTRACT: We identified three patients (two of them relatives) with RA and signs of scleroderma whose sera contained a high titre of IgG class antibodies against the nucleoli and the nucleoplasm of cells of different mammalian origins. Sera from these patients uniformly immunoprecipitated four polypeptides, from a 35S-methionine-labelled HeLa cell extract, whose mol. wts were 120, 105, 95 and 42 kD. Of these, the 95-kD protein was highly phosphorylated. By immunoblotting, these sera reacted with 105-, 95- and 42-kD proteins and affinity-purified antibodies from these, demonstrating that 105- and 95-kD proteins shared cross-reactive epitopes. Moreover, affinity-purified antibodies from each of these proteins immunoprecipitated the whole complex. Localization studies using immunoelectron microscopy and in vivo actinomycin-D-treated cells demonstrated that the 105-, 95- and 42-kD proteins were present in the granular component of the nucleolus and the nucleoplasm. In addition, the 105- and 95-kD were present in free polyribosomes as well as ribosomes attached to endoplasmic reticulum. Pulse/chase experiments strongly suggested that the complex was accomplished shortly after a 10-min pulse. It was preferentially present in the nucleus after a 2 h chase and in both nucleus and cytoplasm after a 5 h chase. We conclude that a protein complex with a main nucleolar distribution is a new autoantigen (p105-p42) recognized by autoantibodies present in the serum of a subgroup of patients with RA and scleroderma signs. These antibodies could be useful as diagnostic markers and as tools for further studies involving the biology of the nucleolus.
    Clinical & Experimental Immunology 12/1998; 114(2):301-10. · 3.41 Impact Factor
  • J. F. MONTES, J. A. DEL RÍO, M. DURFORT, J. GARCÍA-VALERO
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    ABSTRACT: The venerid clams, Tapes decussatus and T. semidecussatus, develop a singular defensive response to Perkinsus atlanticus infection. This reaction involves the redifferentiation of recruited granulocytes and the expression de novo of the polypeptide p225. To determine whether the association of this defensive process with the natural parasitism by P. atlanticus is unique, the inflammatory response elicited by inoculations of bacteria, algae and non-viable P. atlanticus pre-zoosporangia in the clam T. semidecussatus was shown. Inoculated areas were heavily infiltrated by granulocytes and delimited by myofibroblast-like cells and extracellular matrix. While bacteria and algae were phagocytosed by the infiltrated granulocytes, pre-zoosporangia were not. After 40 days, neither cell redifferentiation nor the expression of p225 was observed. These findings indicate that both redifferentiation and p225 expression are specifically associated with P. atlanticus infection. After 5-bromodeoxyuridine administration, only a few cells were labelled either in the inoculated zone or in the cellular reaction around P. atlanticus meronts. Significant differences between untreated and inoculated groups were observed in the epicardic connective tissue soon after injection. These results suggest that this anatomical region could be the main site of haemocyte proliferation stimulated after inoculation of foreign bodies in T. semidecussatus.
    Parasitology 04/1997; 114(04). · 2.36 Impact Factor
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    ABSTRACT: The effect of prenatal ethanol exposure on the intestinal maturation of rat fetuses was investigated to understand the nutritional alterations found in the offspring of alcoholic mothers. Female Wistar rats were maintained on solid diet and 25% ethanol solution as drinking fluid during pregnancy, and non-alcoholic isocaloric pregnant mothers were used as controls. At birth, intestines from unsuckled pups were removed for study. The weight and length of the intestine decreased significantly when ethanol was present in utero. Ultrastructural evaluation of the epithelium revealed loss of contact between neighboring enterocytes and abnormal dilation of the cisternae of the Golgi apparatus in ethanol-exposed pups. Further, increased lysosome-like vesiculation and enhanced lysosomal beta-galactosidase activity was observed in these neonates. The total number of absorptive enterocytes in the epithelium was reduced by 30% in ethanol-exposed neonates as compared to controls, due to altered cell growth and death during fetal life. Ethanol in utero stimulated epithelial cell migration which compensated cell loss, as demonstrated by 5'-Bromodeoxyuridine labeling. These findings could have important implications for the assimilation of nutrients and failure to thrive in infants with fetal alcohol syndrome.
    Teratology 12/1996; 54(5):245-54.
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    J F Montes, G Estrada, M D López-Tejero, J García-Valero
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    ABSTRACT: Cytoskeletal changes after longterm exposure to ethanol have been described in a number of cell types in adult rat and humans. These changes can play a key part in the impairment of nutrient assimilation and postnatal growth retardation after prenatal damage of the intestinal epithelium produced by ethanol intake. To determine, in the newborn rat, which cytoskeletal proteins are affected by longterm ethanol exposure in utero and to what extent. The offspring of two experimental groups of female Wistar rats: ethanol treated group receiving up to 25% (w/v) of ethanol in the drinking fluid and control group receiving water as drinking fluid. Single and double electron microscopy immunolocalisation and label density estimation of cytoskeletal proteins on sections of proximal small intestine incubated with monoclonal antibodies against actin, alpha-tubulin, cytokeratin (polypeptides 1, 5, 6, 7, 8, 10, 11, and 18), and with a polyclonal antibody anti-beta 1,4-galactosyl transferase as trans golgi (TG) or trans golgi network (TGN) marker, or both. SDS-PAGE technique was also performed on cytoskeletal enriched fractions from small intestine. Western blotting analysis was carried out by incubation with the same antibodies used for immunolocalisation. Intestinal epithelium of newborn rats from the ethanol treated group showed an overexpression of cytoskeletal polypeptides ranging from 39 to 54 kDa, affecting actin and some cytokeratins, but not tubulin. Furthermore, a cytokeratin related polypeptide of 28-29 kDa was identified together with an increase in free ubiquitin in the same group. It was noteworthy that actin and cytokeratin were abnormally located in the TG or the TGN, or both. Longterm exposure to ethanol in utero causes severe dysfunction in the cytoskeleton of the developing intestinal epithelium. Actin and cytokeratins, which are involved in cytoskeleton anchoring to plasma membrane and cell adhesion, are particularly affected, showing overexpression, impaired proteolysis, and mislocalisation.
    Gut 07/1996; 38(6):846-52. · 10.73 Impact Factor
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    ABSTRACT: At birth, the mammalian small intestine displays regional differences in morphology as well as complex proximal-to-distal (horizontal) patterns of protein distribution. Lactase-phlorizin hydrolase (LPH), an enterocyte-specific disaccharidase crucial for the digestion of lactose in milk, reveals a characteristic horizontal pattern of expression at birth. However, it is not certain whether this topographic pattern is due to variations in epithelial structure along the length of the small intestine or to regional differences in the transcription of the LPH gene. In order to understand the mechanisms that regulate the regionalization of LPH at birth, we characterized the epithelial structure along the horizontal axis using stereologic techniques and correlated these data with the patterns of lactase activity and LPH mRNA abundance in the small intestine of unsuckled, newborn rats. Epithelial volume and microvillar surface area per unit of intestinal length decreased three-to fourfold from duodenum to distal ileum. In contrast, lactase activity and LPH mRNA abundance were highest in proximal jejunum and lowest in the most proximal and distal ends of the small intestine. Mean lactase activity per cell in proximal duodenum, proximal jejunum, and distal ileum was estimated at 12.0, 26.7, and 5.6 nU/absorptive enterocyte, respectively, and paralleled the concentration of LPH mRNA in the same segments: 20, 45, and 15 molecules of LPH mRNA/absorptive enterocyte. Our data indicate that horizontal gradients of lactase activity in the newborn rat intestine do not depend on epithelial organization or on enteral factors, since the horizontal gradient is established before suckling. Each absorptive enterocyte along the small intestine expresses lactase activity in a position-dependent manner which is controlled at the level of mRNA abundance.
    Journal of Cellular Physiology 06/1996; 167(2):341-8. · 4.22 Impact Factor
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    JF Montes, M Durfort, J García-Valero
    Diseases of Aquatic Organisms - DISEASE AQUAT ORG. 01/1996; 26:149-157.
  • Juan F. Montes, Mercè Durfort, José García-Valero
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    ABSTRACT: Parasitosis by the trophozoite protozoan Perkinsus sp. (Apicomplexa, Perkinsea) induces in the gill filaments of the clam Tapes semidecussatus (Mollusca, Bivalvia) a cellular reaction, which is constituted by infiltrated granulocytes. This cellular reaction has characteristics of those of a holocrine gland, since the parasites are encapsulated by the secretion product of the granulocytes after cell death. An enriched fraction of prezoosporangia and their associated capsule was obtained after culture of the parasitized gills in fluid thioglycollate medium. Specific polypeptides from this fraction were separated by SDS-PAGE and isolated for rabbit immunizations. The serum obtained against an Mr 225 kDa polypeptide, revealed its exclusive localization in the capsule and in the granules of the infiltrated granulocytes, thus indicating that this polypeptide is synthesized by these cells and secreted, in a polarized way, around the trophozoites resulting in their encapsulation. Selective deglycosylation of the polypeptide, by Endo H and alkaline -elimination, did not show an effect on its molecular weight or antibody recognition. Furthermore, the absence of the 225 kDa band in the Western-blots of non-parasitized gills indicated the specific association of this polypeptide with the parasitosis. Finally, this is the first tissue-specific factor described in molluscs in relation to defence mechanisms.
    Cell and Tissue Research 03/1995; 280(1):27-37. · 3.68 Impact Factor
  • Juan F. Montes, Mercè Durfort, José García-Valero
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    ABSTRACT: The cellular defence mechanism of the clam Tapes semidecussatus (Mollusca, Bivalvia) against infection by the parasite protozoan Perkinsus sp. (Apicomplexa, Perkinsea) was studied in the gill filaments. The parasites, localized in the connective tissue, induced a cellular reaction involving infiltrated granulocytes. These showed a secretory aspect, with the cytoplasm being filled by membrane-bound granules with internal membranes. The holocrine secretion, which was proteic and slightly glycosylated, by the granulocytes gave rise to the encapsulation of the parasites. After incubation with lectins from Canavalia ensiformis, Triticum vulgaris, Helix pomatia, Glycine max, Arachis hypogaea, Ricinus communis (agglutinin), Ulex europeus I and Limax flavus, a lack of specific and/or main sugars was observed in the plasma membrane of parasite and granulocyte, and in the wall of the former. Furthermore, GalNac1,3GalNac and -d-gal residues were only detected in association with the internal membranes and dense regions of both granules and capsule, respectively. Blood granulocytes were observed at the periphery of the cellular reaction, close to blood vessels, and these appeared to re-differentiate to give the granulocytes of the cellular reaction. The data reported here suggest that this parasite induces the infiltration and re-differentiation of specialized cells in the host mollusc. In addition, a polarized secretion of a specific defence product is described for the first time.
    Cell and Tissue Research 02/1995; 279(3):529-538. · 3.68 Impact Factor