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1.
Med Mycol ; 46(8): 795-804, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18608937

ABSTRACT

This study addresses the recognition of laminin by Paracoccidioides brasiliensis conidia, as well as its possible role in the adherence of conidia to A549 cells. Adherence of conidia to immobilized laminin was shown to be specific, as anti-laminin antibodies, soluble laminin or the laminin-derived peptides IKVAV and CDPGYIGSR inhibited this interaction. RGD containing peptides and various monosaccharides had no effect on adherence, with the exception of N-acetylneuraminic acid. Pre-treatment of conidia with fibrinogen and fibronectin, but not with BSA, also resulted in significant inhibition, suggesting that P. brasiliensis conidia might cross-recognize host proteins involved in colonization. In assays using transmission electron microscopy, we observed internalization of conidia 30 min after exposition to A549 cells. Laminin present on the surface of A549 cells shown to serve as mediator of this interaction, with a significant decrease in fungal adherence when the epithelial cells were pre-treated with anti-laminin antibodies or when conidia were pre-incubated with either soluble laminin or the laminin-specific peptides. Together these results suggest that the recognition of laminin by P. brasiliensis conidia is a key process in the interaction with pulmonary epithelial cells, where this extracellular matrix protein acts as bridging molecule.


Subject(s)
Laminin/metabolism , Paracoccidioides/physiology , Pulmonary Alveoli/microbiology , Analysis of Variance , Basement Membrane/metabolism , Cell Adhesion , Cell Adhesion Molecules/antagonists & inhibitors , Cell Adhesion Molecules/metabolism , Cell Line, Tumor , Epithelial Cells/metabolism , Epithelial Cells/microbiology , Fungal Proteins/metabolism , Humans , Immobilized Proteins/metabolism , Laminin/genetics , Microscopy, Electron, Transmission , Peptides/metabolism , Pulmonary Alveoli/cytology , Spores, Fungal/physiology
2.
Microb Pathog ; 44(5): 389-401, 2008 May.
Article in English | MEDLINE | ID: mdl-18083324

ABSTRACT

We examined the ability of Paracoccidioides brasiliensis conidia to interact with fibronectin, fibrinogen and with A549 cells, in order to establish the nature of the molecules involved. Conidia bound to immobilized proteins in a concentration-dependent manner. Antibodies against fibronectin and fibrinogen inhibited the fungal adherence to the corresponding proteins; as did laminin and fibronectin, but not fibrinogen when added in soluble form; however, the fibrinogen fragment D interfered with adhesion in a significant manner. Various monosaccharides and RGD/RGDS peptides had no effect on adherence to fibronectin or fibrinogen, while N-acetylneuraminic acid (NANA) abolished adherence to both proteins. Additionally, these proteins were detected on the surface of A549 cells. Inhibition assays showed a significant decrease in fungal adherence when A549 cells were treated with anti-fibrinogen, anti-fibronectin antibodies and a purified adhesin of P. brasiliensis (32-kDa protein); or when conidia were treated with these soluble proteins, mAb anti-32-kDa protein, RGD peptides and NANA. These results suggest that fibrinogen and fibronectin facilitate the adherence of conidia to A549 cells probably through the interaction with adhesin-type molecules or a sialic acid based recognition system. These interactions appear to play a role in the initial fungal attachment to the lung, and consequently, also in the pathogenesis of paracoccidioidomycosis.


Subject(s)
Cell Adhesion Molecules/metabolism , Cell Adhesion/physiology , Fibrinogen/metabolism , Fibronectins/metabolism , Paracoccidioides/physiology , Spores, Fungal/physiology , Cell Line , Epithelial Cells/microbiology , Humans
3.
Toxicon ; 40(8): 1107-114, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12165312

ABSTRACT

The clinical and epidemiological features, as well as complications presented by 39 patients with Bothrops, Porthidium and Bothriechis snakebites, are described. Patients were admitted during 1 year in 25 hospitals of Antioquia and Chocó and then, they were transferred to the Hospital Universitario San Vicente de Paúl in Medellín, 30 of them because of the presence of complications, eight because of lack of antivenoms and another one because of the desire of his relatives. Thirty--one (79.5%) of the patients were male, 13 (33.3%) children, 59% of them were bitten at the lower extremities, the majority (74.4%) by Bothrops asper. Twenty-one (53.8%) of the patients were initially attended by traditional healers and sought medical attention at the local hospitals after 2h in 87.2% of the cases. Edema (100%), hemorrhage (74.4%), blistering (38.5%) and necrosis (38.5%), were the local signs of envenomation, while blood coagulation alteration (79.5%), hematuria (74.4%), gingival bleeding (43.6%), hypovolemic shock (23.1%) and oliguria (23.1%), were the systemic signs of envenomation. The final grade of envenomation was severe in 29 patients (74.4%). Thirty patients (76.9%) had one or more complications of the envenomation: acute renal failure (ARF), 15 (38.5%); soft-tissue infection, 12 (30.8%); central nervous system (CNS) hemorrhage, 5 (12.8%); compartment syndrome, 3 (7.7%); soft--tissue hematomas, 6 (15.4%); and Abruptio placentae, one (2.6%). There were four deaths (10.3%), two from ARF and two from cerebral hemorrhage. Fourteen other patients (35.9%) had sequelae. The onset of serotherapy after 2h of the bite was associated with the occurrence of ARF and CNS hemorrhage (p=0.02), as well as the risk of death and sequelae (RR=2.5).


Subject(s)
Bothrops , Snake Bites/complications , Snake Bites/epidemiology , Viperidae , Adolescent , Adult , Aged , Animals , Anti-Infective Agents/adverse effects , Anti-Infective Agents/therapeutic use , Antivenins/adverse effects , Antivenins/therapeutic use , Bacterial Infections/etiology , Bacterial Infections/microbiology , Child , Child, Preschool , Colombia/epidemiology , Female , Hematoma/drug therapy , Hematoma/pathology , Hemorrhage/chemically induced , Hemorrhage/pathology , Humans , Infant , Kidney Function Tests , Male , Medicine, Traditional , Middle Aged , Snake Bites/pathology , Treatment Outcome
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