Joaquin Rueda

Universidad Miguel Hernández de Elche, Elche, Valencia, Spain

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Publications (27)44.52 Total impact

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    ABSTRACT: In order to study acute retinal toxicity of intravitreal triamcinolone acetonide (TA) at high doses in an animal model, thirty New Zealand albino rabbits were injected with intravitreal TA. The animals were divided in five groups: Group 1 received an intravitreal injection of 0.1 mL balanced salt solution; Group 2, 0.1 mL of the solvent (0.99 mg of benzyl alcohol); Group 3, received 4 mg/0.1 mL TA; Group 4, 20mg/0.1 mL TA; and Group 5, 30 mg/0.1 mL TA. A standard light and dark adapted electroretinogram (ERG) was obtained prior and 28 days after the injection. The animals were sacrificed 28 days after the injection and the eyes were enucleated and examined by electron (EM) and light microscopy (LM) using hematoxylin-eosin, Nissl fluorescent, and immunohistochemistry (glial fibrillary acidic protein). No statistically significant differences in ERG before and 28 days after the injection were found. LM and EM did not show retinal damage in any animal. One eye developed bacterial endophthalmitis 14 days after the injection. Intravitreal TA up to 30 mg does not seem to have acute toxic effects on the function (ERG) or the structure (LM, EM) of the retina of albino rabbits.
    Experimental Eye Research 03/2007; 84(2):342-8. DOI:10.1016/j.exer.2006.10.006 · 3.02 Impact Factor
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    ABSTRACT: To describe changes in rabbit retina after intravitreous injection of perfluorohexyloctane (F6H8). Intravitreous injections of C3F8 were performed in the right eye of 48 male New Zealand albino rabbits. All 48 eyes were injected with C3F8. The animals were divided in three groups of 18 each. 18 eyes (6 in each group) were used as controls and 30 (10 in each group) were further injected with F6H8. Animals were sacrificed at days 15, 30, and 60 and the eyes processed for light and electron microscopy and immunohistochemistry. Vitreous tracts were observed behind the lens in all groups. Epiretinal and retrolental membranes developed in most of the treated eyes. Light microscopy showed retinal vacuolization in all eyes. No significant ultrastructural changes appeared in any of them. Macrophages were observed in the inner limiting membrane. Ultrastructural findings can be considered signs of good tolerance to F6H8, though the appearance of epiretinal membranes associated with the presence of macrophagic response suggests we should refrain from using F6H8 until results from clinical trials are available.
    Current Eye Research 10/2005; 30(9):773-9. DOI:10.1080/02713680590959439 · 1.66 Impact Factor
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    Joaquin Rueda, Raquel Cantos, David J Lim
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    ABSTRACT: During development, different epithelial cells in the mouse cochlea express different cell surface glycoconjugates, which may reflect membrane specialization. Some of the lectins tested in this study (SBA, succ-WGA, and PSA) labeled the sensory cells of the cochlea around birth. Other lectins (WGA, Con A, RCA-II, and PHA-E) labeled surfaces of the sensory cells, particularly the stereocilia, from early stages of development (gestation day (GD) 16) through 21 days after birth. These may be adhesion molecules needed to attach the newly forming tectorial membrane (TM) to the stereocilia. Lectin staining of the developing TM revealed that the substructures of the TM are biochemically distinct. Lectin staining also showed the temporal sequence of the expression of cytoplasmic glycoconjugates of the cochlear epithelium during development. Biochemical changes during development are probably the result of different cells being involved in the production of glycoconjugates, and may have functional significance, specifically with regard to the expression of adhesion and/or signaling molecules.
    The Anatomical Record Part A Discoveries in Molecular Cellular and Evolutionary Biology 10/2003; 274(2):923-33. DOI:10.1002/ar.a.10109
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    ABSTRACT: The deficit of thyroid hormone leads to several structural and physiological modifications in the auditory receptor: the outer hair cells present an immature morphology, abnormal persistence of the afferent dendrites and incomplete development of the efferent terminals. The aim of this work was to perform a quantitative and morphometric study of the spiral ganglion neurons in control and hypothyroid animals. The cochleae from both experimental groups were processed in order to obtain plastic sections. In control animals the size of the neurons increased throughout development and was larger in the basal than in the apical portion of the cochlea. In hypothyroid animals, the cell death that takes place normally during development did not occur, and there was no differentiation into types I and II neurons. The size of the neurons also increased with development in treated animals, but they were smaller than in control animals, and in this case the neurons in the apex were larger than in the base. This study shows that hypothyroidism alters the normal development of the spiral ganglion neurons.
    Neuroscience Research 05/2003; 45(4):401-8. DOI:10.1016/S0168-0102(03)00009-9 · 2.15 Impact Factor
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    ABSTRACT: Congenital hypothyroidism induces developmental abnormalities in the auditory receptor, causing deafness due to a poor development of the outer hair cells (OHCs) and a lack of synaptogenesis between these cells and the olivocochlear axons. This efferent innervation is formed by two separate systems: the lateral system, which originates in the lateral superior olive (LSO) and reaches the inner hair cells; and the medial system, which originates in the ventral nucleus of the trapezoid body (VNTB) and innervates the OHCs. A previous study carried out in our laboratory showed that in congenitally hypothyroid animals, the neurons which give rise to the efferent system are normal in number and distribution, although smaller in size. The aim of the present work was to study the efferent fibers in the auditory receptor of hypothyroid animals, by means of stereotaxic injections of biotinylated dextran amine in the nuclei that give rise to the olivocochlear system: LSO and VNTB. In hypothyroid animals, injections in LSO gave rise to lateral olivocochlear fibers lacking their characteristic dense terminal arbors, while injections in the VNTB-labeled fibers terminating in the spiral bundle region, far from the OHCs with which they normally contact. In the latter case, only a small percentage of labeled fibers reached the OHCs area, giving off only two radial branches maximum. Because the number of neurons which develop into the efferent innervation was normal in hypothyroid animals, we conclude that medial fibers may contact a new target.
    The Journal of Comparative Neurology 01/2003; 459(4):454-67. DOI:10.1002/cne.10620 · 3.51 Impact Factor
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    ABSTRACT: Congenital hypothyroidism results in deafness that is caused by changes in the auditory receptor, including scanty development of the outer hair cells and a lack of synaptogenesis between these cells and the efferent system. although the afferent population is present. The normal efferent innervation of the cochlea originates in the superior olivary complex, arising from efferent neurons belonging to the lateral or to the medial olivocochlear system. In the rat, the former is constituted by neurons located in the lateral superior olivary nucleus, that project to the inner hair cells, while the later originates in the ventral nuclei of the trapezoid body and project to the outer hair cells. The aim of this work is to study the localization, number and morphology of the olivochochlear neurons in congenital hypothyroid animals by means of the injections of the retrograde tracers, either fast blue or cholera toxin, in the cochlea. The mean total number of labeled olivocochlear neurons after injection of fast blue in hypothyroid animals was 1,016, and in control ones was 1,027. Using cholera toxin, the mean total number of labeled olivocochlear neurons was slightly lower: 863 in hypothyroid animals versus 910 in control ones. Although both tracers showed no significant differences between groups, when the somatic area of the labeled olivocochlear neurons is considered, the size of all of the three different population of cells (lateral olivocochlear neurons, medial olivocochlear neurons and shell neurons) was significantly lower in the hypothyroid rats. This is the first study of the olivocochlear neurons in hypothyroid animals. The conclusion from this work is that in hypothyroid rats the labeled olivocochlear neurons are significantly smaller but that there is not any modification in the localization and number of the labeled olivocochlear neurons, suggesting that thyroid hormones are necessary for the neuronal growth. However, most of the medial olivocochlear neurons do not make contact with their target, so their maintenance suggests that the axons are in contact with other structures of the cochlea.
    Anatomy and Embryology 05/2000; 201(4):245-57. DOI:10.1007/s004290050315 · 1.39 Impact Factor
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    ABSTRACT: The pattern of lectin labeling in the cerebral cortex of the cat was studied using semithin sections. The labeling produced by some lectins (Concanavalin A, Lens culinaris, Phaseolus vulgaris-L, Phaseolus vulgaris-E, Pisum sativum, wheat germ agglutinin, and succynilated-wheat germ) appeared inside every neuron as small cytoplasmic granules, probably corresponding to cisterns of endoplasmic reticulum and/or the Golgi complex. Lectins with affinity for alpha-mannosyl residues (Pisum sativum, Lens culinaris, and Concanavalin A) stained the cell surface of a subset of cortical neurons. The labeled cells were round or polygonal, medium to large neurons present in layers II-VI, exhibiting the morphological features of nonpyramidal cells. Previous lectin studies of perineuronal nets have shown that these extracellular specializations contain N-acetylgalactosamine and N-acetylglucosamine. Our results show that mannose is also a component of perineuronal nets and that lectins specific for alpha-mannose can be used as tools for the cytochemical detection of a separate class of cortical neurons, which have not yet been fully characterized. In addition, some lectins (Bandeiraea simplicifolia, Concanavalin A, Lens culinaris, Phaseolus vulgaris-L, Phaseolus vulgaris-E, Pisum sativum, and succynilated-wheat germ agglutinin) specifically labeled a population of a type of microglia-related cells known as perivascular cells. The data presented here report for the first time the selective staining of perivascular cells and further support the hypothesis that they are different from typical microglial cells.
    Brain Research Bulletin 08/1999; 49(4):251-62. DOI:10.1016/S0361-9230(99)00056-8 · 2.97 Impact Factor
  • Joaquin Rueda, Raquel Cantos, D J Lim
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    ABSTRACT: The development of stereociliary attachment to the tectorial membrane was investigated in the mouse cochlea using transmission and scanning electron microscopy. At the 18th gestational day, only the major tectorial membrane can be identified covering the greater epithelial ridge and the inner hair cells in all turns. At the 19th gestational day, the minor tectorial membrane was first seen in the basal turn, over the outer hair cells. During early stages of development, the stereocilia of hair cells were surrounded by a loose fibrillar material underneath the tectorial membrane. After the 10th postnatal day, the outer hair cells' stereocilia were attached to Kimura's (or Hardesty's) membrane, while inner hair cells' stereociliary bundles were attached to the undersurface of the tectorial membrane near the Hensen's stripe. Between the 10th and the 14th postnatal days, the space between the inner hair cells and the first row of outer hair cells widened by virtue of the growth of the heads of pillar cells, and the inner hair cells' stereocilia were displaced towards the Hensen's stripe. After the 14th postnatal day, the inner hair cells' stereociliary bundles detached from the tectorial membrane, while the outer hair cells' stereocilia remained attached to it. The tip-link system, which connects the tips of the stereocilia to the next tallest stereocilia, is present at birth in the outer hair cells. The marginal pillar, that anchored the tectorial membrane to the underlying organ of Corti during development, first appeared on the 6th postnatal day and disappeared on the 14th-15th postnatal day. The present data together with other reports support the idea that although some structures, such as hair cells' stereocilia and innervation, are already formed early during development, the cochlear microarchitecture is not fully developed morphologically and ready to function normally until the end of the second postnatal week in the mouse.
    Anatomy and Embryology 12/1996; 194(5):501-14. DOI:10.1007/BF00185996 · 1.39 Impact Factor
  • Toxicology Letters 10/1996; 88:27. DOI:10.1016/S0378-4274(96)80097-X · 3.36 Impact Factor
  • Toxicology Letters 09/1996; 88:26-27. DOI:10.1016/0378-4274(96)88445-1 · 3.36 Impact Factor
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    ABSTRACT: The glycogen content of several types of supporting cells in the organ of Corti of the rat was demonstrated histochemically at the ultrastructural level using the periodic acid-thiocarbohydrazide-silver proteinate method. The development of the glycogen stores was assessed by means of a semiquantitative method in normal and congenitally-hypothyroid rats. At birth, all the cell types of the developing organ of Corti showed in their cytoplasms numerous glycogen particles. As development proceeded, the density of glycogen particles increased, reaching the highest value at the 8th postnatal day for the cells of the organ of Kölliker, inner pillar cell and outer pillar cell. On the other hand, the peak of maximum glycogen content in Deiters' cells was accomplished at the 15th postnatal day. From the day in which the maximum value was obtained onwards, the glycogen content in all the cell types fell and disappeared. Congenital hypothyroidism induced by propylthyouracil only affected the normal development of the density of glycogen particles in Deiters' cells, which didn't undergo the increase observed in the normal animals, remaining at values similar to those obtained at birth. This finding, together with previous similar results on the glycogen content of the inner ear's outer hair cells suggest that hypothyroidism selectively impairs the development of those organ of Corti's cells which mature on the second postnatal week, in the rat.
    Journal für Hirnforschung 02/1995; 36(1):67-75.
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    ABSTRACT: The glycoconjugates in the cytoplasm of inner ear interdental cells and those constituting the limbal tectorial membrane were identified by a post-embedding cytochemical method using low-temperature embedding in Lowicryl K4M and labeling with biotinylated lectins, goat anti-biotin antibody, rabbit anti-goat antibody, and gold-labeled protein A in control animals, and after the systemic injection of pilocarpine. The lectins used were ConA, PHA-E, PSA, RCA, SBA, Succ-WGA, UEA, and WGA. In control animals, a semiquantitive analysis of gold particles showed that Succ-WGA produced the strongest labeling on the tectorial membrane, followed by SBA, ConA, WGA, RCA, PHA-E, and PSA. The lowest values were obtained with UEA. The cytoplasm of the interdental cells was also labeled with all the lectins, but the number of particles/microns2 was lower than on the tectorial membrane. The concentration of gold particles on the limbal tectorial membrane in pilocarpine-treated animals was higher than in control animals for some lectins (RCA, PSA, UEA) but lower for others (WGA, SBA, PHA-E, Succ-WGA). The changes in the labeling pattern of the cytoplasm of the interdental cells paralleled those in the tectorial membrane. These results demonstrate that the saccharide composition of the limbal tectorial membrane can be modified by systemic injection of pilocarpine. This action may take place through a change in either the secretion rate or the amount of some glycoconjugates by the interdental cells.
    Journal of Histochemistry and Cytochemistry 04/1994; 42(3):405-16. DOI:10.1177/42.3.8308257 · 2.40 Impact Factor
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    ABSTRACT: Tectal cells appear at birth in the outer part of the developing organ of Corti. At first they are attached to the basilar membrane, but later they ascend through the auditory epithelium. During the 1st postnatal week (coinciding with the development of the minor tectorial membrane), the newly formed tectal cells show several cytological characteristics suggesting increased metabolic and secretory activities, which include: (1) a large Golgi complex, (2) abundant amorphous material inside the cisterns of rough endoplasmic reticulum, and (3) dense granules inside the mitochondrial matrix. All these features gradually disappear, and by the 14th postnatal day the tectal cells show a dark cytoplasm and few and short microvilli. In addition, tectal cells were stained selectively by some lectins. These findings suggest that tectal cells may participate in the secretion of some components of the minor tectorial membrane, different from those produced by Deiters' cells, Hensen's cells and pillar cells.
    Anatomy and Embryology 06/1993; 187(5):425-32. DOI:10.1007/BF00174418 · 1.39 Impact Factor
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    ABSTRACT: Subcutaneous injection of pilocarpine in guinea pigs resulted in the following ultrastructural changes: 1) the apical cavities of the interdental cells were filled with a substance indistinguishable from the overlying amorphous layer of the TM; 2) a great number of spherical structures appeared over the limbal portion of the tectorial membrane. In TEM photomicrographs these structures displayed the same appearance as the amorphous layer of the TM and were usually continuous to it; 3) the number of holes that decorate the upper surface of the limbal portion of the TM was dramatically increased and it was found that they connect the endolymphatic space to the apical cavities of the interdental cells; 4) there was an increase in the number of the small extracellular vesicles found in the clear spaces of the tectorial membrane. These facts suggest that pilocarpine stimulates the secretion of the interdental cells, confirming the existence of the secretory processes previously described (Prieto et al., 1990). These findings can be related to the turnover of the TM in the adult animal and, perhaps, to the secretion of some organic compound to the endolymph. We postulate that the actions of pilocarpine on the interdental cells are most probably mediated by the activation of muscarinic acetylcholine receptors in these cells.
    Hearing Research 08/1991; 54(1):59-66. DOI:10.1016/0378-5955(91)90136-W · 2.85 Impact Factor
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    ABSTRACT: Fixation with a mixture of tannic acid and glutaraldehyde reveals a darkly stained substance in the intercellular clefts between juxtapposed interdental cells, where it is included by pynocytotic vesicles. Over the interdental cells, similar-sized vesicles (35-45 nm) are present in clear spaces of the amorphous layer of the limbal portion of the tectorial membrane. Some images suggest that they may be secreted through small disruptions of the membrane of the interdental cells' microvilli. In addition, a TA-unstained, amorphous material is present inside both basal ducts and apical cavities of the interdental cells, thus suggesting another secretory route from the basal region of the interdental cells towards either the endolymph, or the tectorial membrane. These two secretion processes coexist in a single interdental complex, and the two secretion products may be involved in the turnover of the adult tectorial membrane and/or the secretion of some component of the endolymph.
    Hearing Research 05/1990; 45(1-2):51-61. DOI:10.1016/0378-5955(90)90182-O · 2.85 Impact Factor
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    ABSTRACT: Lectin staining has been used to detect mono- and oligosaccharides in normal and hypothyroid developing organs of Corti in the rat. Eight developmental stages were studied (1, 5, 8, 10, 15, 20, 50 and 60 days after birth). Congenital hypothyroidism was induced by oral administration of propylthyouracil to pregnant rats. Labelling of the tectorial membrane with 3 lectins, Ulex europaeus agglutinin-I (UEA-I), Lens culinaris agglutinin (LCA) and Ricinus communis agglutinin-I (RCA-I) showed no significant differences between normal and hypothyroid animals. Staining with peanut agglutinin (PNA) showed that the hypothyroid adult tectorial membrane (but not the normal one) possesses the disaccharide galactose + N-acetyl galactosamine. Phaseolus vulgaris agglutinin-L (PHA-L) labels the whole tectorial membrane in both groups of animals, but the staining is more intense in the hypothyroid one for a narrow band of oligosaccharide located just between the tectorial membrane and the underlying organ of Kölliker. Both soybean agglutinin (SBA) and succinylated wheat germ agglutinin (WGA) stain the tectorial membrane as well as the cytoplasm of the cells constituting the inner portion of the organ of Kölliker; this latter feature disappears in the normal animals about the 8th postnatal day, but it is abnormally preserved until the 60th postnatal day in the hypothyroid ones. In the adult hypothyroid animals, 3 of the lectins (LCA, PHA-L and WGA) stain extracellular conglomerates located under the synaptic pole of the outer hair cells.
    Developmental Brain Research 04/1990; 52(1-2):141-9. DOI:10.1016/0165-3806(90)90229-R · 1.78 Impact Factor
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    ABSTRACT: The density of glycogen particles in organ of Corti's sensory cells was measured to determine the effect of congenital hypothyroidism upon the normal development of this energy source. This density in both normal and hypothyroid inner hair cells remains in low values from birth to adulthood. On the other hand, that of normal outer hair cells undergoes a great increase between the 10th and the 20th postnatal days, coinciding with the maturation of both the efferent innervation of these cells and the tuning properties of the auditory receptor. The glycogen stores of the hypothyroid outer hair cells do not show any significant increase from birth to adulthood. This latter fact suggests that the congenital hypothyroidism restrains the development of an important energy source of outer hair cells, most surely disturbing the physiological processes relying on glycogen metabolism.
    Developmental Brain Research 02/1990; 51(1):138-41. DOI:10.1016/0165-3806(90)90268-4 · 1.78 Impact Factor
  • Advances in oto-rhino-laryngology 02/1990; 45:140-2.
  • Advances in oto-rhino-laryngology 02/1990; 45:133-5.
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    ABSTRACT: The effects of locally applied kainic acid on cells and fibers in the rat cochlea were examined in a quantitative and ultrastructural study. Doses of 5 nM per microliter of artificial perilymph destroyed part of the spiral ganglion type I cell population, with no ototoxic effects on cochlear hair cells or supporting cells. Type II cells also appeared unaffected. A quantitative evaluation of the cell loss with the 5 nM dosage showed that 34% of spiral ganglion neurons were lost 10 days after treatment. Doses of 20 nM per microliters and 40 nM per microliters did not result in increasing neuronal loss. This differential toxicity could reflect the presence of a sub-population of spiral ganglion cells with an increased number of KA receptors.
    Hearing Research 07/1989; 40(1-2):65-74. DOI:10.1016/0378-5955(89)90100-7 · 2.85 Impact Factor

Publication Stats

260 Citations
44.52 Total Impact Points

Institutions

  • 2000–2007
    • Universidad Miguel Hernández de Elche
      • • Department of Histology and Anatomy
      • • Faculty of Medicine
      Elche, Valencia, Spain
  • 1986–1996
    • University of Alicante
      • • Phisiology, Genetics and Microbiology
      • • Ecology
      Alicante, Valencia, Spain