51
|
Peralta-Hernández JM, Manríquez J, Meas-Vong Y, Rodríguez FJ, Chapman TW, Maldonado MI, Godínez LA. Photocatalytic properties of nano-structured TiO2-carbon films obtained by means of electrophoretic deposition. JOURNAL OF HAZARDOUS MATERIALS 2007; 147:588-93. [PMID: 17314007 DOI: 10.1016/j.jhazmat.2007.01.053] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 01/12/2007] [Accepted: 01/15/2007] [Indexed: 05/14/2023]
Abstract
Recent studies have shown that the light-absorption and photocatalytic efficiencies of TiO2 can be improved by coupling TiO2 nano-particles with nonmetallic dopants, such as carbon. In this paper, we describe the electrophoretic preparation of a novel TiO2-carbon nano-composite photocatalyst on a glass indium thin oxide (ITO) substrate. The objective is to take better advantage of the (e-/h+) pair generated by photoexcitation of semiconducting TiO2 particles. The transfer of electrons (e-) into adjacent carbon nano-particles promotes reduction of oxygen to produce hydrogen peroxide (H2O2) which, in the presence of iron ions, can subsequently form hydroxyl radicals (*OH) via the Fenton reaction. At the same time, *OH is formed from water by the (h+) holes in the TiO2. Thus, the *OH oxidant is produced by two routes. The efficiency of this photolytic-Fenton process was tested with a model organic compound, Orange-II (OG-II) azo dye, which is employed in the textile industry.
Collapse
|
52
|
Forcén P, Oriol L, Sánchez C, Rodríguez FJ, Alcalá R, Hvilsted S, Jankova K. Methacrylic azopolymers for holographic storage: A comparison among different polymer types. Eur Polym J 2007. [DOI: 10.1016/j.eurpolymj.2007.05.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
53
|
Rodríguez FJ, Wang FX, Canfield BK, Cattaneo S, Kauranen M. Multipolar tensor analysis of second-order nonlinear optical response of surface and bulk of glass. OPTICS EXPRESS 2007; 15:8695-8701. [PMID: 19547204 DOI: 10.1364/oe.15.008695] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We use two-beam second-harmonic generation to perform a quantitative tensor analysis of the effective dipolar surface nonlinearity and the separable multipolar bulk nonlinearity for BK7 glass. The most straightforward, self-consistent interpretation of the results is obtained when the effective surface response is assumed to have approximate Kleinman symmetry and the bulk contribution is dominated by magnetic, rather than quadrupole, effects.
Collapse
|
54
|
Rabagliati FM, Rodríguez FJ, Alla A, Martínez de Ilarduya A, Muñoz-Guerra S. Styrene/(substituted styrene) copolymerization by Ph2Zn–metallocene–MAO systems: Synthesis and characterization of poly(styrene-co-p-hydroxystyrene) copolymers. POLYMER 2007. [DOI: 10.1016/j.polymer.2007.06.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
55
|
Lago N, Rodríguez FJ, Guzmán MS, Jaramillo J, Navarro X. Effects of motor and sensory nerve transplants on amount and specificity of sciatic nerve regeneration. J Neurosci Res 2007; 85:2800-12. [PMID: 17455293 DOI: 10.1002/jnr.21286] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Nerve regeneration after complete transection does not allow for adequate functional recovery mainly because of lack of selectivity of target reinnervation. We assessed if transplanting a nerve segment from either motor or sensory origin may improve specifically the accuracy of sensory and motor reinnervation. For this purpose, the rat sciatic nerve was transected and repaired with a silicone guide containing a predegenerated segment of ventral root (VR) or dorsal root (DR), compared to a silicone guide filled with saline. Nerve regeneration and reinnervation was assessed during 3 months by electrophysiologic and functional tests, and by nerve morphology and immunohistochemistry against choline acetyltransferase (ChAT) for labeling motor axons. Functional tests showed that reinnervation was successful in all the rats. However, the two groups with a root allotransplant reached higher degrees of reinnervation in comparison with the control group. Group VR showed the highest reinnervation of muscle targets, whereas Group DR had higher levels of sensory reinnervation than VR and saline groups. The total number of regenerated myelinated fibers was similar in the three groups, but the number of ChAT+ fibers was slightly lower in the VR group in comparison with DR and saline groups. These results indicate that a predegenerated root nerve allotransplant enhances axonal regeneration, leading to faster and higher levels of functional recovery. Although there is not clear preferential reinnervation, regeneration of motor axons is promoted at early times by a motor graft, whereas reinnervation of sensory pathways is increased by a sensory graft.
Collapse
|
56
|
Holm PC, Rodríguez FJ, Kele J, Castelo-Branco G, Kitajewski J, Arenas E. BMPs, FGF8 and Wnts regulate the differentiation of locus coeruleus noradrenergic neuronal precursors. J Neurochem 2006; 99:343-52. [PMID: 16987254 DOI: 10.1111/j.1471-4159.2006.04039.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In the present study, we investigated the involvement of rhombomere 1 patterning proteins in the regulation of the major noradrenergic centre of the brain, the locus coeruleus. Primary cultures of rat embryonic day 13.5 locus coeruleus were treated with fibroblast growth factor-8, noggin and members of the bone morphogenetic and Wnt protein families. We show that bone morphogenetic proteins 2, 5 and 7 increase and noggin decreases the number of tyrosine hydroxylase-positive locus coeruleus neurons. Interestingly, from all Wnts expressed in the first rhombomere by embryonic day 12.5 in the mice, we only found expression of wnt5a mRNA in the vicinity of the locus coeruleus. In agreement with this finding, from all Wnts studied in vitro, only Wnt5a increased the number of tyrosine hydroxylase-positive neurons in locus coeruleus cultures. Finally, we also found that fibroblast growth factor-8 increased the number of tyrosine hydroxylase-positive cells in locus coeruleus cultures. Neither of the identified factors affected the survival of tyrosine hydroxylase-positive locus coeruleus noradrenergic neurons or the proliferation of their progenitors or neurogenesis. Instead, our results suggest that these patterning signals of rhombomere 1 may work to promote the differentiation of noradrenergic progenitors at later stages of development.
Collapse
|
57
|
Peralta-Hernández JM, Meas-Vong Y, Rodríguez FJ, Chapman TW, Maldonado MI, Godínez LA. In situ electrochemical and photo-electrochemical generation of the fenton reagent: a potentially important new water treatment technology. WATER RESEARCH 2006; 40:1754-62. [PMID: 16626778 DOI: 10.1016/j.watres.2006.03.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 02/23/2006] [Accepted: 03/07/2006] [Indexed: 05/03/2023]
Abstract
In this work, the design and construction of an annular tube reactor for the electrochemical and photo-electrochemical in situ generation of H2O2 are described. By cathodic reduction of dissolved oxygen and the coupled oxidation of water at a UV-illuminated nanocrystalline-TiO2 semiconductor anode, it was found that the electrochemically generated H2O2 can be employed to readily oxidize the model compound Direct Yellow-52 in dilute acidic solution at high rates in the presence of small quantities of dissolved iron(II). Although, the model organic compound is chemically stable under UV radiation, its electrochemical oxidation rate increases substantially when the semiconductor anode is illuminated as compared to the same processes carried out in the dark.
Collapse
|
58
|
Rabagliati FM, Rodríguez FJ, Alla A, Muñoz-Guerra S. Styrene–substituted-styrene copolymerization using diphenylzinc–metallocene–methylaluminoxane systems. POLYM INT 2006. [DOI: 10.1002/pi.2032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
59
|
Tejedor RM, Millaruelo M, Oriol L, Serrano JL, Alcalá R, Rodríguez FJ, Villacampa B. Photoinduced supramolecular chirality in side-chain liquid crystalline azopolymers. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b518269g] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
60
|
Rodríguez FJ, Sánchez C, Villacampa B, Alcalá R, Cases R, Millaruelo M, Oriol L. Fast and stable recording of birefringence and holographic gratings in an azo-polymethacrylate using a single nanosecond light pulse. J Chem Phys 2005; 123:204706. [PMID: 16351292 DOI: 10.1063/1.2124647] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Pulsed light-induced recording in azobenzene polymers has recently been studied due to its potential use in optical storage applications. In this paper we study the photoinduced birefringence (Deltan) and holographic grating recording in an azobenzene side chain liquid-crystalline polymethacrylate irradiating with a single 4 ns light pulse at 532 nm. For some irradiation conditions, Deltan grows in less than 50 ns reaching an essentially stable value of about 10(-2). Holographic gratings have been registered using intensity and polarization patterns. Fast response and stability, similar to those of Deltan, was observed in the holographic recording process. Both light-induced anisotropy and relief contributions have been found in the case of gratings recorded using intensity patterns, relief being the dominant contribution at high recording energies. Polarization gratings have been recorded using two orthogonally circularly polarized beams. The resultant gratings showed stable efficiencies up to 0.8% (measured at 633 nm in 1-mum-thick films) and no measurable relief was observed.
Collapse
|
61
|
Varela I, Cadiñanos J, Pendás AM, Gutiérrez-Fernández A, Folgueras AR, Sánchez LM, Zhou Z, Rodríguez FJ, Stewart CL, Vega JA, Tryggvason K, Freije JMP, López-Otín C. Accelerated ageing in mice deficient in Zmpste24 protease is linked to p53 signalling activation. Nature 2005; 437:564-8. [PMID: 16079796 DOI: 10.1038/nature04019] [Citation(s) in RCA: 357] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Accepted: 07/20/2005] [Indexed: 01/09/2023]
Abstract
Zmpste24 (also called FACE-1) is a metalloproteinase involved in the maturation of lamin A (Lmna), an essential component of the nuclear envelope. Both Zmpste24- and Lmna-deficient mice exhibit profound nuclear architecture abnormalities and multiple histopathological defects that phenocopy an accelerated ageing process. Similarly, diverse human progeroid syndromes are caused by mutations in ZMPSTE24 or LMNA genes. To elucidate the molecular mechanisms underlying these devastating diseases, we have analysed the transcriptional alterations occurring in tissues from Zmpste24-deficient mice. We demonstrate that Zmpste24 deficiency elicits a stress signalling pathway that is evidenced by a marked upregulation of p53 target genes, and accompanied by a senescence phenotype at the cellular level and accelerated ageing at the organismal level. These phenotypes are largely rescued in Zmpste24-/-Lmna+/- mice and partially reversed in Zmpste24-/-p53-/- mice. These findings provide evidence for the existence of a checkpoint response activated by the nuclear abnormalities caused by prelamin A accumulation, and support the concept that hyperactivation of the tumour suppressor p53 may cause accelerated ageing.
Collapse
|
62
|
Lago N, Ceballos D, Rodríguez FJ, Stieglitz T, Navarro X. Long term assessment of axonal regeneration through polyimide regenerative electrodes to interface the peripheral nerve. Biomaterials 2005; 26:2021-31. [PMID: 15576176 DOI: 10.1016/j.biomaterials.2004.06.025] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Accepted: 06/15/2004] [Indexed: 10/26/2022]
Abstract
Polyimide sieve electrodes were implanted between the severed ends of the sciatic nerve in rats. The degree of axonal regeneration through the electrode was examined by physiological and histological methods from 2 to 12 months postimplantation. Regeneration was successful in the 30 animals implanted. Functional reinnervation of hindlimb targets progressed to reach maximal levels at 6 months. Comparatively, the reinnervation of distal plantar muscles was lower than that of proximal muscles and of digital nerves. The number of regenerated myelinated fibers increased from 2 to 6 months, when it was similar to control values. The majority of myelinated fibers crossing the via holes and regenerated through the distal nerve had a normal appearance. However, in a few cases decline of target reinnervation and loss of regenerated nerve fibers was found from 6 to 12 months postimplantation. Motor axons labeled by ChAT immunoreactivity regenerated scattered within minifascicles, although they were found at higher density at the periphery of the regenerated nerve. The number of ChAT-positive axons was markedly lower distally than proximally to the sieve electrode.
Collapse
|
63
|
Capote A, Rodríguez FJ, Blasco A, Muñoz MF. Jacob's disease associated with temporomandibular joint dysfunction: a case report. Med Oral Patol Oral Cir Bucal 2005; 10:210-4. [PMID: 15876963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Jacob's disease is regarded a rare condition in which a joint formation is established between an enlarged mandibular coronoid process and the inner aspect of the zygomatic body. Chronic temporomandibular joint (TMJ) disk displacement has been proposed as etiological factor of coronoid process enlargement. We present a 23-year-old woman with long-standing TMJ dysfunction and restricted interincisal opening, who developed a progressive zygomatic asymmetry. The patient underwent treatment by intraoral coronoidectomy and homolateral TMJ arthroscopy in the same surgery. The histopathological diagnosis of the coronoid sample was cartilage-capped exostoses with presence of articular fibrous cartilage. Although the low prevalence of this entity, it should be considered as a possible diagnosis in patients with progressive limitation of mouth opening, although a TMJ syndrome may be present as a cause of this entity.
Collapse
|
64
|
Sánchez-Muñoz A, Aguado JM, López-Martín A, López-Medrano F, Lumbreras C, Rodríguez FJ, Colomer R, Cortés-Funes H. Usefulness of antibiotic-lock technique in management of oncology patients with uncomplicated bacteremia related to tunneled catheters. Eur J Clin Microbiol Infect Dis 2005; 24:291-3. [PMID: 15902539 DOI: 10.1007/s10096-005-1291-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
65
|
Rodríguez FJ, Rodríguez A, Mendoza-Londoño R, Tamayo ML. X-LINKED RETINOSCHISIS IN THREE FEMALES FROM THE SAME FAMILY: A PHENOTYPE–GENOTYPE CORRELATION. Retina 2005; 25:69-74. [PMID: 15655444 DOI: 10.1097/00006982-200501000-00010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To describe the clinical findings and outcome for three homozygous females affected with X-linked retinoschisis (XLRS) in a large Colombian family with 26 affected males. METHODS Retrospective review of charts for females from a family with XLRS who underwent complete ophthalmologic examinations, ancillary tests, clinical genetic evaluation, and molecular studies. RESULTS Three female patients (6 eyes) with clinical findings of XLRS were identified. The patients' ages ranged from 10 to 37 years. Initial visual acuity was equal to or worse than 20/50 in 4 eyes (66%) of 2 patients. Four eyes (66%) were hyperopic. Intraocular pressure was normal in all eyes. Three eyes (50%) had cataracts, and vitreous veils were present in 3 (50%). The optic disk was pale in 6 eyes (100%). Foveal schisis was present in 6 eyes (100%). Peripheral retinal schisis was present in five eyes. A silvery gloss or tapetal-like retinal reflex or sheen was observed in 6 eyes (100%), and dendritic lines were found in 2 (33%). One eye had a retinal break, and one had a retinal detachment. Two eyes underwent cataract extraction; one patient underwent bilateral cryotherapy, one, laser treatment, and one, scleral buckling. Final visual acuity was 20/50 to 20/100 in 2 eyes and 20/200 to 20/400 in 4. Follow-up ranged from 7 to 22 years. Molecular analysis showed that all three female patients were homozygous for the allele 639delG of (on) the XRLS1 gene. CONCLUSIONS Compared with their affected male relatives, three females from a family with XLRS had similar ocular findings and a more severe course of disease. These findings are explained by the fact that these patients were homozygous for a mutation in the XLRS1 gene.
Collapse
|
66
|
Rabagliati FM, Pérez MA, Rodríguez FJ, Caro CJ, Crispel N. Further studies on styrene/styrene derivative copolymerizations using combined diphenylzinc-additive initiator systems. POLYM INT 2004. [DOI: 10.1002/pi.1714] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
67
|
Rodríguez FJ, Valero-Cabré A, Navarro X. Regeneration and functional recovery following peripheral nerve injury. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ddmod.2004.09.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
68
|
Zapata PD, Colas B, López-Ruiz P, Ropero RM, Martín RM, Rodríguez FJ, González FJ, López JI, Angulo JC. [Phosphotyrosine phosphatase SHP-1, somatostatin and prostate cancer]. Actas Urol Esp 2004; 28:269-85. [PMID: 15248398 DOI: 10.1016/s0210-4806(04)73075-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We review the mechanisms involved in prostatic growth based on androgens and product of neuroendocrine secretion, with special reference to the role of somatostatin (SS) in the inhibition of neoplastic growth. Our contributions in the field confirm the antiproliferative effect of SS on the prostate is mediated by phosphotyrosine phosphatase SHP-1, that is present in human prostate. This enzyme plays a role in the control of prostatic cell proliferation and in the progression of prostate cancer. Besides, we consider its presence may determine the therapeutic potential of SS in the control of prostate cancer.
Collapse
|
69
|
Rabagliati FM, Cancino RA, Pérez MA, Rodríguez FJ. Styrene/(Styrene Derivative) and Styrene/(1-Alkene) Copolymerization using Ph2Zn-Additive Initiator Systems. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/masy.200451207] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
70
|
Udina E, Rodríguez FJ, Verdú E, Espejo M, Gold BG, Navarro X. FK506 enhances regeneration of axons across long peripheral nerve gaps repaired with collagen guides seeded with allogeneic Schwann cells. Glia 2004; 47:120-9. [PMID: 15185391 DOI: 10.1002/glia.20025] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We assessed the effects of FK506 administration on regeneration after a 6-mm gap repair with a collagen guide seeded with allogeneic Schwann cells (SCs) in the mouse sciatic nerve. SCs were isolated from predegenerated adult sciatic nerves and expanded in culture using a defined medium, before being seeded in the collagen guide embedded in Matrigel. Functional reinnervation was evaluated by noninvasive methods to determine recovery of motor, sensory, and autonomic functions in the hindpaw over 4 months postoperation. Histological analysis of the regenerated nerves was performed at the end of the study. Using simple collagen guides for tubulization repair, treatment with an immunosuppressant dose of FK506 (5 mg/kg/day) resulted in significant improvement of the onset and the degree of reinnervation. While the introduction of allogeneic SCs did not improve regeneration versus a collagen guide filled only with Matrigel, treatment with FK506 allowed for successful regeneration in all the mice and for significant improvement in the levels of functional recovery. Compared with the untreated group, there was greater survival of transplanted pre-labeled SCs in the FK506-treated animals. Morphologically, the best nerve regeneration (in terms of nerve caliber and numbers of myelinated axons) was obtained with SC-seeded guides from FK506-treated animals. Thus, FK506 should be considered as adjunct therapy for various types of tubulization repair.
Collapse
|
71
|
Holm PC, Rodríguez FJ, Kresse A, Canals JM, Silos-Santiago I, Arenas E. Crucial role of TrkB ligands in the survival and phenotypic differentiation of developing locus coeruleus noradrenergic neurons. Development 2003; 130:3535-45. [PMID: 12810600 DOI: 10.1242/dev.00565] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The role of glial cell-line derived neurotrophic factor (GDNF) and neurotrophins in the development of locus coeruleus noradrenergic neurons was evaluated. We found that two neurotrophic factors previously reported to prevent the degeneration of lesioned adult central noradrenergic neurons, GDNF and neurotrophin 3 (NT3), do not play significant roles in the prenatal development of locus coeruleus noradrenergic neurons, as demonstrated by: (1) the lack of alterations in double Gdnf/Nt3 null mutant mice; and (2) the lack of survival-promoting effects of GDNF and/or NT3 in rat E13.5 primary cultures. In contrast, null mutant mice for TrkB, the tyrosine kinase receptor for brain-derived neurotrophic factor and neurotrophin 4, displayed a clear loss of locus coeruleus noradrenergic neurons. In accordance with this, treatment of rat E13.5 primary cultures with TrkB ligands prevented the early loss of noradrenergic neurons and maintained their survival for up to 6 days in vitro. Moreover, an additional 5-10-fold increase in the number of tyrosine hydroxylase positive noradrenergic neurons was detected after 12 hours in culture. This second effect of TrkB ligands involved neither proliferation nor survival, because the number of BrdU- or TUNEL-positive noradrenergic neurons did not change and the effect was elicited by delayed administration of either factor. Because TrkB ligands increased the number of tyrosine hydroxylase-positive cells expressing Phox2a, a paired homeodomain protein required for the development of locus coeruleus noradrenergic neurons, but did not affect the number of Phox2a-positive tyrosine hydroxylase-negative cells, our results suggest that the second effect of TrkB ligands may involve promoting or inducing a noradrenergic phenotype. In summary, our findings suggest that, unlike NT3 and GDNF, TrkB ligands are required and sufficient to promote the development of central noradrenergic neurons.
Collapse
|
72
|
Rabagliati FM, Pérez MA, Cancino RA, Rodríguez FJ, Caro CJ. Homo- and copolymerization of styrene using combined diphenylzinc-additive initiator systems. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/masy.200390148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
73
|
Rodríguez FJ, Gómez N, Labrador RO, Butí M, Ceballos D, Cuadras J, Verdú E, Navarro X. Improvement of regeneration with predegenerated nerve transplants in silicone chambers. Restor Neurol Neurosci 2003; 14:65-79. [PMID: 12671272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
We compared regeneration and reinnervation of target organs after sciatic nerve resection and repair with silicone tubes filled with saline solution or with a peroneal nerve segment as a nerve transplant versus an autologous sciatic nerve graft leaving either 4 mm or 6 mm gaps. The aims of this study were to evaluate the effects of predegeneration and donor immunogenicity of nerve transplants. Functional reinnervation was assessed by noninvasive methods to determine recovery of sweating, sensory and motor functions in the hindpaw after three months postoperation for 4 mm and four months postoperation for 6 mm gap groups. Morphometrical analysis of the regenerated nerve were performed at the end of the follow-up. The group with an autograft achieved faster and higher levels of reinnervation for the four functions tested than any of the groups repaired by tubulization. The introduction of a small nerve transplant improved regeneration and reinnervation with respect to a saline solution filled tube slightly with a 4 mm gap, but significantly with a 6 mm long gap. The beneficial effects of the nerve transplant were significantly increased when it was predegenerated, while disappearing when its cellular component was eliminated by repeated freezing. The immunogenicity of the nerve transplant dramatically affected nerve regeneration, as it was impeded by an heterologous transplant in the tube. In summary, the use of silicone chambers with an autologous predegenerated nerve transplant may be an alternative for repairing long gaps in injured nerves, approaching the level of success of an ideal autologous nerve graft.
Collapse
|
74
|
Navarro X, Rodríguez FJ, Ceballos D, Verdú E. Engineering an artificial nerve graft for the repair of severe nerve injuries. Med Biol Eng Comput 2003; 41:220-6. [PMID: 12691445 DOI: 10.1007/bf02344893] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nerve repair with tubes has a limit to regeneration depending upon the length of the gap. The characteristics of the guide, in terms of permeability, durability and adhesiveness, also influence regeneration. Considering the importance of the cellular component in regeneration, the development of artificial grafts, composed of a biocompatible nerve guide filled with a neurotropic matrix and seeded with Schwann cells (SCs), is an interesting option to enhance nerve regeneration and provide an alternative to the classical autologous nerve graft. We evaluated the ability of SCs transplanted into a nerve guide to improve regeneration after sciatic nerve resection, leaving a 6-mm gap, in the mouse. Syngeneic, isogeneic and autologous SCs were suspended in Matrigel and seeded in resorbable guides, and compared to acellular guides and to nerve autografts. The immunogenicity of the transplanted SCs clearly influenced the outcome. Transplants of autologous SCs resulted in only slightly lower levels of reinnervation than autografts, but higher recovery and number of regenerated axons than transplants of isologous and syngeneic SCs, and than acellular guides. Thus, by combined developments on nerve guides, extracellular matrix components and cell transplantation, an artificial graft has been designed that allows axonal regeneration across long gaps to levels comparable with an autograft.
Collapse
|
75
|
Verdú E, Labrador RO, Rodríguez FJ, Ceballos D, Forés J, Navarro X. Alignment of collagen and laminin-containing gels improve nerve regeneration within silicone tubes. Restor Neurol Neurosci 2003; 20:169-79. [PMID: 12515893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
PURPOSE Placement of extracellular matrix components has been used as a mean to enhance axonal growth across nerve long gaps repaired by tubulization. However, such matrices may impede axonal regeneration depending on its density and microgeometry. METHODS Silicone tubes were prefilled with collagen or laminin-containing gels and implanted into a 6 mm gap, a length considered limiting for regeneration, in the mouse sciatic nerve. Gels were polymerized prior to implantation either in horizontal position or subjected to gravitational (in vertical position) or to magnetic forces to induce longitudinal alignment of the fibrils. Recovery of motor, sensory and sudomotor functions in the hindpaw was evaluated during 4 months postoperation. RESULTS Reinnervation started earlier and achieved slightly higher levels with aligned collagen gels than with the horizontal gel. For the three groups repaired with tubes with Matrigel, there was a gradation of the functional results, reinnervation started earlier and reached higher values in matrix with magnetically-induced, longitudinal orientation than with the horizontal gel, whereas gravitational alignment followed an intermediate evolution. Final morphological evaluation showed more dense residual mass of collagen than of Matrigel at the center of the regenerate nerves. The number of myelinated fibers was increased in tubes with alignment compared to horizontal gels. CONCLUSIONS Alignment of collagen and laminin gels within a silicone tube increases the success and the quality of regeneration in long nerve gaps. The laminin gel performed better than the collagen gel under each condition tested. The combination of an aligned matrix with embedded Schwann cells should be considered in further steps for the development of an artificial nerve graft for clinical application.
Collapse
|