Blood-brain Barrier Breakdown Following Gliotoxic Drug Injection In The Brainstem Of Wistar Rats [ruptura Da Barreira Hematoencefàlica Após Injeção De Droga Gliotóxica No Tronco Encefálico De Ratos Wistar]

Ethidium bromide (EB) causes local astrocytic disappearance, with glia limitans disruption and supposed blood-brain barrier (BBB) breakdown The aim of this study was to investigate the BBB integrity after the injection of 0.1% EB (group E) or 0.9% saline solution (group C) into cisterna pontis of Wistar rats. Brainstem fragments were collected from 24 hours to 31 days post-injection for ultrastructural study and GFAP immuno-histochemical staining. Some animals received colloidal carbon ink by intravenous route at the same periods. In rats from group C, there was no sign of astrocyte loss and no leakage of ink from blood vessels in the injection site. In group E, astrocyte disappearance began at 48 hours and some areas were still devoid of astrocytic processes 31 days after. Leakage of carbon particles was seen from 48 hours to 7 days in the EB-induced lesions. Tight junctions did not show any detectable ultrastructural change due to the lack of perivascular astrocytes.603 A582589Bondan, E.F., Lallo, M.A., Graça, D.L., Desmielinizaçao experimental por brometo de etídio no sistema nervoso central (1998) Rev Univ Guarulhos -Ciênc Biol Saúde, 5, pp. 19-32Bondan, E.F., Lallo, M.A., Graça, D.L., (1998) Efeitos do brometo de etídio no tronco encefálico de ratos Wistar imunossuprimidos com ciclosporina, pp. 1-46. , São Paulo: Coleção Cadernos de Estudos e Pesquisas UNIPBondan, E.F., Graça, D.L., Sinhorini, I.L., Lallo, M.A., Silva, I.M., Pharmacological interference on remyelination in rats submitted to the ethidium bromide model (1998) Arch Anat Cytol Path/Clin Exp Path, 46, p. 536Bondan, E.F., Lallo, M.A., Sinhorini, I.L., Graça, D.L., Schwann cells may express an oligodendrocyte-like remyelinating pattern following ethidium bromide injection in the rat brainstem (1999) Acta Microscopica, 8, pp. 707-708Bondan, E.F., Lallo, M.A., Sinhorini, I.L., Baz, E.I., Paulino, C.A., Graça, D.L., Ultrastructural investigation on the brainstem remyelination after local ethidium bromide injection in rats immunosuppressed with dexamethasone (1999) Acta Microscopica, 8, pp. 709-710Bondan, E.F., Lallo, M.A., Sinhorini, I.L., Pereira, L.A.V., Graça, D.L., The effect of cyclophosphamide on brainstem remyelination following ethidium bromide injection in Wistar rats (2000) J Submicrosc Cytol Pathol, 32, pp. 603-612Graça, D.L., (1986) Investigation into ethidium bromide induced-demyelination in the central nervous system, , Thesis (PhD), University of Cambridge, CambridgeGraça, D.L., Blakemore, W.F., Delayed remyelination in rat spinal cord following ethidium bromide injection (1986) Neuropathol Appl Neurobiol, 12, pp. 593-605Graça, D.L., Pereira, L.A.V., (1990) Dinâmica da impregnaça̧o celular pelo brometo de etídio "in vitro" e "in vivo" (Abstr), pp. 430-431. , Porto Alegre: Anais da 42a Reunia̧o da Sociedade Brasileira para o Progresso da Ciência (SBPC)Pereira, L.A.V., Dertkigill, M.S.J., Graça, D.L., Cruz-Höfling, M.A., Dynamics of remyelination in the brain of adult rats after exposure to ethidium bromide (1998) J Submicrosc Cytol Pathol, 30, pp. 341-348Yajima, K., Suzuki, K., Ultrastructural changes of oligodendroglia and myelin sheats induced by ethidium bromide (1979) Neuropathol Appl Neurobiol, 5, pp. 49-62Yajima, K., Suzuki, K., Demyelination and remyelination in the rat central nervous system following ethidium bromide injection (1979) Lab Invest, 41, pp. 385-392Bondan, E.F., Lallo, M.A., Mielinizaça̧o, desmielinizaça̧o e remielinizaça̧o no SNC: Aspectos histofisiológicos relevantes à formaça̧o e integridade da mielina central (1998) Rev Inst Ciênc Saúde, 16, pp. 103-111Leibowitz, S., Hughes, R.A.C., (1983) Immunology of the nervous system, pp. 2-16. , London: Edward ArnoldSternberger, N.H., Multiple sclerosis as a autoimunne disease: Vascular antigens (1989) Res Immunol, 140, pp. 181-187Janzer, R.C., Raff, M.C., Astrocytes induce blood-brain barrier properties in endothelial cells (1987) Nature, 325, pp. 253-257Risau, W., Induction of blood-brain barrier endothelial cell differentiation (1991) Ann NY Acad Sci, 405, pp. 405-419Peters, A., Palay, S.L., Webster HdeF, (1991) The fine structure of the nervous system. 3. Ed., pp. 290-295. , New York: Oxford Univ PressStewart, P.A., Coomber, B.L., Astrocytes and the blood-brain barrier (1986) Astrocytes: development, morphology and regional specializations of astrocytes, pp. 311-323. , Fedoroff S, Verdanakis A (eds.). London: Academic PressBundgaard, M., Pathways across the vertebrate blood-brain barrier: Morphological viewpoints (1986) Ann NY Acad Sci, 481, pp. 7-18Reese, T.S., Karnovsky, M.J., Fine structural localization of a blood-brain barrier to exogenous peroxidase (1967) J Cell Biol, 34, pp. 207-217Felts, P.A., Smith, K.J., Tilt, E., Blood-brain barrier function in central demyelinating lesions repaired by Schwann cell remyelination (1991) Ann NY Acad Sci, 633, pp. 615-616Weller, R.O., Pathology of multiple sclerosis (1985) Mc Alpine's multiple sclerosis, pp. 301-343. , Matthews WB, Acheson ED, Batchelor Jr (eds.). Edinburgh: Churchill LivingstoneHsu, S.-M., Raine, L., Fanger, H., A comparative study of the peroxidase-antiperoxidase method and an avidin-biotin complex method for studying polypeptide hormones with radioimmunoassay antibodies (1981) Am J Clin Pathol, 75, pp. 734-738Majno, G., Palade, G.E., Studies on inflammation: I. The effect of histamine and serotonin on vascular permeability. An electron microscope study (1961) J Biophys Biochem Cytol, 11, pp. 571-605Reynolds, R., Wilkin, G.P., Cellular reaction to an acute demyelinating/ remyelinating lesion of the rat brainstem: Localization of GD3 ganglioside immunoreactivity (1993) J Neurosc Res, 36, pp. 405-42

Remodeling Of Cortical And Corticocancellous Fresh-frozen Allogeneic Block Bone Grafts - A Radiographic And Histomorphometric Comparison To Autologous Bone Grafts

Objectives: To compare cortical (AL-C) and corticocancellous (AL-CC) fresh-frozen block bone allografts to cortical block bone autografts (AT) used for lateral ridge augmentation in terms of radiographic dimensional maintenance and histomorphometrical graft remodeling. Materials and methods: Twenty-four patients, requiring ridge augmentation in the anterior maxilla prior to implant placement, were treated with AT, AL-C or AL-CC bone blocks (eight patients per graft type). Patients were examined with CBCT prior to, 14 days, and 6-8 months after grafting. Amount of augmentation and dimensional block graft maintenance over time was evaluated by comparing planimetric measurements of the alveolar ridge made on CBCT sections of the augmentation area. During implant installation surgery, 6-8 months after grafting, cylindrical biopsies were harvested perpendicularly to the lateral aspect of the augmented alveolar ridge. The relative volumes of vital and necrotic bone and soft tissues were histomorphometrically estimated. Comparisons among groups and observation times were performed using Friedman test followed by Dunn's post-hoc test. Results: Radiographic evaluation showed that the three types of grafts resulted in a significant increase in alveolar ridge width, with no significant differences among the groups in terms of ridge dimensions at the various observation times. However, significant graft resorption (P = 0.03) was observed in the AL-CC group over time (-8.3 ± 7.1%) compared with the AT and AL-C groups, where a slight increase was observed, on average (1.5 ± 20.6% and 1.3 ± 14.9%, respectively). Histomorphometrical analysis showed that larger amounts of vital bone were found in the biopsies from the AT augmented sites (25.1 ± 11.2%) compared with AL-CC and AL-C augmented sites (9.3 ± 3.8% and 3.9 ± 4.6%, respectively; P ≤ 0.01). AL-CC and AT biopsies had the smallest amount of necrotic bone (38.2 ± 12.1% and 56.7 ± 26.0, respectively) compared with AL-C (83.7 ± 10.8%, P < 0.01) biopsies. AL-CC biopsies showed the largest amount of soft tissues (52.5 ± 11.7%) compared with those from AT (18.1 ± 17.1%, P = 0.03) and AL-C (12.3 ± 8.5%, P < 0.01) sites. Conclusions: AL block bone graft architecture influences significantly its dimensional incorporation and remodeling. Compared with AT bone graft, a small portion of the AL block consists of vital bone 6-8 months after grafting. Cortical AL blocks seem to show the least amounts of vital bone, while corticocancellous AL blocks seem to undergo more resorption over time. © 2014 John Wiley & Sons A/S

Immunohistochemical Staining Of The Macrophagic And Astrocytic Response In The Brainstem Of Wistar Rats Submitted To The Ethidium Bromide Gliotoxic Model And Treated With Cyclophosphamide [marcação Imuno-histoquímica Da Resposta Macrofágica E Astrocitária No Tronco Encefálico De Ratos Wistar Submetidos Ao Modelo Gliotóxico Do Brometo De Etídio E Tratados Com Ciclofosfamida]

The gliotoxic ethidium bromide (EB) was used to study morphologically the macrophagic and astrocytic response under immunosuppression by cyclophosphamide (CY). Astrocyte immunoreactivity to glial fibrillary acidic protein (GFAP) and vimentin (VIM) and macrophagic immunoreactivity to ED1 were investigated after EB injection. Male Wistar rats were injected with 0.9% saline solution (group I), 0.1% BE (group II) and 0.1% EB associated with CY treatment (group III). Brainstem samples were collected from the 1st to the 21st day post-injection for GFAP, VIM and ED1 immunostaining. In groups II and III, it was observed increased immunoreactivity to GFAP and reexpression of VIM. In group II, ED1-positive cells were noted after the 2nd day and in group III, after the 3rd day. On the 14th day post-injection, it was observed a greater quantity of ED1- positive cells in group III than in group II. Apparently, CY did not change the astrocytic response pattern.643 B787793Graça, D.L., Mielinização, desmielinização e remielinização no sistema nervoso central (1998) Arq Neuro-psiquiatr, 46, pp. 292-297Raine, C.S., Morphology of myelin and myelination (1984) Myelin. 2.Ed., pp. 1-50. , Morell P (ed). New York: Plenum PressRaine, C.S., The neuropathology of myelin diseases (1984) Myelin. 2. Ed., pp. 259-310. , Morell P (ed). New York: Plenum PressGraça, D.L., Blakemore, W.F., Delayed remyelination in rat spinal cord following ethidium bromide injection (1986) Neuropathol Appl Neurobiol, 12, pp. 593-605Riet-Correa, G., Fernandes, C.G., Pereira, L.A., Graca, D.L., Ethidium bromide-induced demyelination of the sciatic nerve of adult Wistar rats (2002) Braz J Med Biol Res, 35, pp. 99-104Benveniste, E.N., Cytokines: Influence on glial cell gene expression and function (1992) Neuroimmunoendocrinology. 2.Ed., pp. 106-153. , Blalack JE (ed). Basel: KargerEng, L.F., Lee, Y.L., Intermediate filaments in astrocytes (1995) Neuroglia, pp. 650-666. , Kettenmann H, Ranson BR (eds). New York: OxfordMucke, L., Oldstone, M.B.A., Morris, J.C., Nerenberg, M.I., Rapid activation of astrocyte-specific expression of GFAP-lacZ transgene by focal injury (1991) New Biology, 3, pp. 465-474Bignami, A., Dahl, D., (1994) Glial Cells in the Central Nervous System and Their Reaction to Injury, , Austin: LandesEng, L.R., Shiurba, R.A., Glial fibrillary acidic protein: A review of structure, function, and clinical application (1988) Neuronal and Glial Proteins: Structure, Function and Clinical Application, pp. 339-359. , Marangos PJ, Campbell I, Cohen RM (eds). New York: Academic PressTakamyia, Y., Kohsaka, S., Toya, S., Otani, M., Tsukuda, Y., Immuno-histochemical studies on the proliferation of reactive astrocytes and the expression of cytoskeletal proteins following brain injury (1988) Dev Brain Res, 38, pp. 201-210Streit, W.J., Microglial cells (1995) Neuroglia, pp. 85-96. , Kettenmann H, Ranson BR (eds). New York: OxfordDijkstra, C.D., Dopp, E.A., Jolong, P., Kraal, G., The heterogeneity of mononuclear phagocytes in lymphoid organs: Distinct MO subpopulations in the rat recognized by monoclonal antibodies ED1, ED2 and ED3 (1985) Immunology, 56, pp. 351-358Damoiseaux, J.G.M.C., Dopp, E.A., Calame, W., Chao, D., MacPherson, G.G., Dijkstra, C.D., Rat macrophage lysosomal membrane antigen recognized by monoclonal antibody ED1 (1994) Immunology, 83, pp. 140-147Wyss-Coray, T., Mucke, L., Inflammation in neurodegenerative disease: A double-edged sword (2002) Neuron, 35, pp. 419-432Giulian, D., Glia as part of the immune system (1995) Neuroglia, pp. 671-684. , Kettenmann H, Ranson BR (eds). New York: OxfordVan Furth, R., Phagocytic cells: Development and distribution of mononuclear phagocytes in normal steady state and inflammation (1988) Inflammation: Basic Principles and Clinical Correlates, pp. 281-295. , Gallin JI, Goldstein IM, Snyderman R (eds). New York: Raven PressVan't Wout, J.W., Linde, I., Leijh, P.C.J., Van Furth, R., Effect of irradiation, cyclophosphamide, and etoposide (VP-16) on number of peripheral blood and peritonial leukocytes in mice under normal conditions and during acute inflammatory reaction (1989) Inflammation, 3, pp. 1-14Bach, J.F., Immunosuppressive therapy of autoimmune diseases (1993) Trends Pharmacol Sci, 14, pp. 213-216Counihan, T.J., Feighery, C., Immunosuppressive therapy in autoimmune disease: A review (1991) Irish J Med Sci, 160, pp. 199-205Hoffman, G.S., Immunosuppressive therapy for autoimmune diseases (1993) Ann Allergy, 70, pp. 263-270Bondan, E.F., Lallo, M.A., Sinhorini, I.L., Pereira, L.A.V.D., Graça, D.L., The effect of cyclophosphamide on brainstem remyelination following local ethidium bromide injection in Wistar rats (2000) J Submicroscopic Cytol Pathol, 32, pp. 603-612Hsu, S.M., Raine, L., Fanger, H., A comparative study of the peroxidase-antiperoxidase method and an avidin-biotin complex method for studying polypeptide hormones with radioimmunoassay antibodies (1981) Am J Clin Pathol, 75, pp. 734-738Fernaud-Espinosa, I., Nietro-Sampedro, M., Bovolenta, P., Diffferential activation of microglia and astrocytes in aniso- and isomorphic gliotic tissue (1993) Glia, 8, pp. 277-291Bondan, E.F., Lallo, M.A., Sinhorini, I.L., Baz, E.I., Paulino, C.A., Graça, D.L., Ultrastructural investigation on the brainstem remyelination after local ethidium bromide injection in rats immunosuppressed with dexamethasone (1999) Acta Microscopica, 8, pp. 709-710Schiffer, D., Giordana, M.T., Migheli, A., Giaccone, G., Pezzotta, S., Mauro, A., Glial fibrillary acidic protein and vimentin in experimental glial reaction of the rat brain (1986) Brain Res, 374, pp. 110-118Petito, C.K., Morgello, S., Felix, J.C., Lesse, M.L., The two patterns of reactive astrocytosis in postischemic rat brain (1990) J Cer Blood Flow Metab, 10, pp. 850-859Fujita, T., Yoshimine, T., Maruno, M., Hayakawa, T., Cellular dynamics of macrophages and microglial cells in reaction to stab wounds in rat cerebral cortex (1998) Acta Neurochir, 140, pp. 275-27

Alveolar Ridge And Maxillary Sinus Augmentation Using Rhbmp-2: A Systematic Review

Purpose: The aim of this systematic review was to evaluate clinical and safety data for recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier when used for alveolar ridge/maxillary sinus augmentation in humans. Materials and Methods: Clinical studies/case series published 1980 through June 2012 using rhBMP-2/ACS were searched. Studies meeting the following criteria were considered eligible for inclusion: >10 subjects at baseline and maxillary sinus or alveolar ridge augmentation not concomitant with implant placement. Results: Seven of 69 publications were eligible for review. rhBMP-2/ACS yielded clinically meaningful bone formation for maxillary sinus augmentation that would allow placement of regular dental implants without consistent differences between rhBMP-2 concentrations. Nevertheless, the statistical analysis showed that sinus augmentation following autogenous bone graft was significantly greater (mean bone height: 1.6mm, 95% CI: 0.5-2.7mm) than for rhBMP-2/ACS (rhBMP-2 at 1.5mg/mL). In extraction sockets, rhBMP-2/ACS maintained alveolar ridge height while enhancing alveolar ridge width. Safety reports did not represent concerns for the proposed indications. Conclusions: rhBMP-2/ACS appears a promising alternative to autogenous bone grafts for alveolar ridge/maxillary sinus augmentation; dose and carrier optimization may expand its efficacy, use, and clinical application. © 2013 Wiley Periodicals, Inc

Effect Of Nitrofen In The Final Stages Of Development Of The Diaphragm Muscle In Rats [efeito Do Nitrofen Na Fase Final Do Desenvolvimento Da Musculatura Do Diafragma Em Ratos]

PURPOSE: To evaluate the expression of myosin in muscle fibers of the diaphragm in experimental congenital diaphragmatic hernia (CDH). METHODS: Fetuses of pregnant rats were divided into four groups: External Control (EC), composed of non-manipulated rats; Nitrofen, composed of pregnant rats that received 100 mg of nitrofen (2,4-dichloro-4'nitrodiphenyl ether) diluted in olive oil on gestational day (GD) 9.5, whose fetuses developed CDH (N+) or not (N-), and Olive Oil Placebo (OO), composed of pregnant rats that received the oil on the same GD. The fetuses were collected on GD 18.5, 19.5, 20.5 and 21.5 (term = 22 days). We obtained body weight (BW) and photographed the diaphragm area (DA), hernia area (HA) and subsequent calculated the HA/DA ratio in N+ group. Samples of Diaphragm muscle were processed for histological staining with H/E and immunohistochemistry (IHQ) for myosin. RESULTS: The fetuses of N- and N+ groups had decreased BW and DA compared to EC and OO groups (p <0.001). HA was decreased on GD 18.5 compared to 21.5 (p <0.001) and the HA/DA ratio showed no difference. IHQ showed decreased expression of myosin in nitrofen groups. CONCLUSION: CDH induced by nitrofen model contributes to the understanding of muscularization in the formation of the diaphragm where the myosin expression is decreased.28SUPPL.11318Greer, J.J., Cote, D., Allan, D.W., Zhang, W., Babiuk, R.P., Ly, L., Lemke, R.P., Bagnall, K., Structure of the primordial diaphragm and defects associated with nitrofen-induced CDH (2000) J Appl Physiol, 89, pp. 2123-2129Allan, D.W., Greer, J.J., Pathogenesis of nitrofen-induced congenital diaphragmatic hernia in fetal rats (1997) J Appl Physiol, 83, pp. 338-347Stege, G., Fenton, A., Jaffray, B., Nihilism in the 1990s: The true mortality of congenital diafragmatic hernia (2003) Pediatrics, 112, pp. 532-535Tannuri, U., Heart hypoplasia in an animal model of congenital diaphragmatic hernia (2001) Rev Hosp Clin Fac Med Sao Paulo, 56, pp. 173-178Allan, D.W., Greer, J.J., Polysialylated NCAM expression during motor axon outgrowth and myogenesis in the fetal rat (1998) J Comp Neurol, 391, pp. 275-292Brotto, M.A., Biesiadecki, B.J., Brotto, L.S., Nosek, T.M., Jin, J.P., Coupled expression of troponin T and troponin I isoforms in single skeletal muscle fibers correlates with contractility (2006) Am J Physiol Cell Physiol, 290, pp. C567-C576Andersen, D.H., Incidence of congenital diaphragmatic in the young of rats bred on a diet deficient in vitamin A (1941) AM J Dis Child, 62, pp. 888-889Schmidt, A.F., Gonçalves, F.L., Nassr, A.C., Pereira, L.A., Farmer, D., Sbragia, L., Antenatal steroid and tracheal occlusion restore vascular endothelial grouth factor receptors in congenital diaphragmatic hernia rat model (2010) Am J Obstet Gynecol, 203 (184), pp. e13-e20Clugston, R.D., Zhang, W., Greer, J.J., Early development of the primordial mammalian diaphragm and cellular mechanisms of nitrofen-induced congenital diaphragmatic hernia (2010) Birth Defects Res a Clin Mol Teratol, 88, pp. 15-24Dingemann, J., Doi, T., Ruttenstock, E., Puri, P., The role of primary myogenic regulatory factors in the developing diaphragmatic muscle in the nitrofen-induced diaphragmatic hernia (2011) Pediatr Surg Int, 27, pp. 579-582Mayer, S., Metzger, R., Kluth, D., The embryology of the diaphragm (2011) Semin Pediatr Surg, 20, pp. 161-169Tovar, J.A., Congenital diaphragmatic hernia (2012) Orphanet J Rare Dis, 7, p. 1Babiuk, R.P., Greer, J.J., Diaphragm defects occur in a CDH hernia model independently of myogenesis and lung formation (2002) Am J Physiol Lung Cell Mol Physiol, 283, pp. 1310-1314Gayan-Ramirez, G., Decramer, M., Clinical relevance of myosin isoforms in the diaphragm (2000) Rev Mal Respir, 17, pp. 574-584Kelly, A.M., Rosser, B.W., Hoffman, R., Panettieri, R.A., Schiaffino, S., Rubinstein, N.A., Nemeth, P.M., Metabolic and contractile protein expression in developing rat diaphragm muscle (1991) J Neurosci, 11, pp. 1231-124

Albumin is synthesized in epididymis and aggregates in a high molecular mass glycoprotein complex involved in sperm-egg fertilization

The epididymis has an important role in the maturation of sperm for fertilization, but little is known about the epididymal molecules involved in sperm modifications during this process. We have previously described the expression pattern for an antigen in epididymal epithelial cells that reacts with the monoclonal antibody (mAb) TRA 54. Immunohistochemical and immunoblotting analyses suggest that the epitope of the epididymal antigen probably involves a sugar moiety that is released into the epididymal lumen in an androgen-dependent manner and subsequently binds to luminal sperm. Using column chromatography, SDS-PAGE with in situ digestion and mass spectrometry, we have identified the protein recognized by mAb TRA 54 in mouse epididymal epithelial cells. The ∼65 kDa protein is part of a high molecular mass complex (∼260 kDa) that is also present in the sperm acrosomal vesicle and is completely released after the acrosomal reaction. The amino acid sequence of the protein corresponded to that of albumin. Immunoprecipitates with anti-albumin antibody contained the antigen recognized by mAb TRA 54, indicating that the epididymal molecule recognized by mAb TRA 54 is albumin. RT-PCR detected albumin mRNA in the epididymis and fertilization assays in vitro showed that the glycoprotein complex containing albumin was involved in the ability of sperm to recognize and penetrate the egg zona pellucida. Together, these results indicate that epididymal-derived albumin participates in the formation of a high molecular mass glycoprotein complex that has an important role in egg fertilization. © 2014 Arroteia et al.The epididymis has an important role in the maturation of sperm for fertilization, but little is known about the epididymal molecules involved in sperm modifications during this process. We have previously described the expression pattern for an antigen in epididymal epithelial cells that reacts with the monoclonal antibody (mAb) TRA 54. Immunohistochemical and immunoblotting analyses suggest that the epitope of the epididymal antigen probably involves a sugar moiety that is released into the epididymal lumen in an androgen-dependent manner and subsequently binds to luminal sperm. Using column chromatography, SDS-PAGE with in situ digestion and mass spectrometry, we have identified the protein recognized by mAb TRA 54 in mouse epididymal epithelial cells. The ∼65 kDa protein is part of a high molecular mass complex (∼260 kDa) that is also present in the sperm acrosomal vesicle and is completely released after the acrosomal reaction. The amino acid sequence of the protein corresponded to that of albumin. Immunoprecipitates with anti-albumin antibody contained the antigen recognized by mAb TRA 54, indicating that the epididymal molecule recognized by mAb TRA 54 is albumin. RT-PCR detected albumin mRNA in the epididymis and fertilization assays in vitro showed that the glycoprotein complex containing albumin was involved in the ability of sperm to recognize and penetrate the egg zona pellucida. Together, these results indicate that epididymal-derived albumin participates in the formation of a high molecular mass glycoprotein complex that has an important role in egg fertilization9