Biomedical subjects
Publications and source records attributed to R Robert.
Binding of fibrinogen to various Candida albicans strains has been investigated by immunofluorescence microscopy on kidney sections of experimentally infected mice. Fibrinogen appeared to bind to both mycelium and blastospores in situ whereas previous studies, carried out in vitro, have shown fibrinogen binding to mycelial elements only.
Adherence of Candida albicans to host tissues is considered a crucial step in the pathogenesis of candidiasis. Using in vitro assays, it was demonstrated that the yeast-mycelium transition was an important phenomenon in the acquisition of adhesive properties. Proteins with MWs of 60, 68, 200 and greater than 200 kDa seemed to be involved in germ tube adherence to plastic surfaces. Likewise, recent investigations have revealed that C. albicans expresses on its surface receptors which interact with a wide variety of host proteins, particularly some extracellular matrix components like fibronectin, laminin and collagen. Plasmatic components, such as fibrinogen, iC3b and C3d, have also been proposed as mediators of adherence of C. albicans. Thus, by their reaction with laminin, fibrinogen and C3d, the mannoproteins of 68 and 60 kDa demonstrated multiple biological activities. Proteins of similar MWs were detected as C3d and iC3b receptors, the latter showing similarities with the neutrophil CR3. Based upon the antigenic, structural and functional homologies between the candidal receptors and mammalian integrins, it was postulated that these fungal cell adhesion molecules (F-CAM) are members of the integrin family. Interactions with host proteins and molecular mimicry of mammalian adhesion molecules may be a fertile area for further research.
A comparative study of serial anatomic sections in the transverse, frontal and sagittal planes with corresponding MRI sections of the pelvis allowed the authors to define the most suitable sectional planes and MRI modes for a morphologic study of the levator ani muscle. This study shows the value of MRI examination in the assessment of anorectal malformations.
Four patients with adult respiratory distress syndrome developed sinus bradycardia during weaning procedures with no evidence of hypoxemia. Bradycardia occurred immediately after the patients' endotracheal tubes were disconnected from the ventilator and most of the time resolved after reconnection. However, 3 patients eventually deteriorated, requiring advanced life support and for one of them, cardiac pacing. The precise mechanism of these bradycardic episodes remains unclear but was unrelated to hypoxemia or acid-base disorder.
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A new non-adherent cell line derived from spontaneous mutation of TG180 cells was adapted to in vitro culture in a defined culture medium. This cell line can be used for in vitro production and cloning of Toxoplasma gondii by limiting dilution.
We have previously shown that Listeria monocytogenes serovar 1/2b can bind strongly to bovine albumin (BA) glycosylated by glucosamine or fucosylamine with about 20 to 30 carbohydrate residues per albumin molecule. We now show that the binding is time-dependent, reversible, saturable and specific. The two glycosylated compounds inhibit each other competitively. Scatchard analysis showed that about 100 molecules of BA-glucosamide (heptameric configuration) and 14,300 molecules of BA-fucosylamide (monomeric configuration) bound per bacterial cell. The apparent dissociation constants for BA-glucosamide and BA-fucosylamide were found to be 3.9 x 10(-14) M and 3.5 x 10(-13) M, respectively.
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Two monoclonal antibodies (MAbs), 3D9 with reported specificity for Candida albicans hyphae, and 3B7 with reported specificity for morphological forms of C. albicans found in vivo, were tested by indirect immunofluorescence with C. albicans cells that were grown in 12 different environments (four different culture media incubated at various temperatures) and whose cellular morphology was estimated in terms of morphology index (Mi). Both MAbs reacted strongly with cells with Mi greater than 3.0, i.e., with pseudohyphal and hyphal forms, but in Eagle's medium at 26 degrees C and in a modified Sabouraud's broth medium at 30 degrees C, some reactivity was also found with cells of lower Mi (i.e., yeast forms). Therefore, it was concluded that the hyphal phenotype and the epitopes reactive with the MAbs were co-expressed but that the epitopes could also be expressed independently of the hyphal phenotype. The results confirm the propensity of C. albicans for variation of its surface antigenic composition.
Several studies have shown that protozoa bind to glycoproteins or neoglycoproteins. Here we report that Toxoplasma gondii binds strongly to bovine serum albumin-glucosamide. The binding was rapid, time dependent, partially reversible, saturable, and specific. Scatchard analysis showed about 40,000 molecules of bovine serum albumin-glucosamide per toxoplasma cell. The apparent dissociation constant was found to be 4.46 x 10(-8) M.
We report the outcome of nosocomial legionnaires' disease in three patients who were isolated in the same sterile unit after allogeneic bone marrow transplantation. In all three cases the disease presented with dramatic pulmonary symptoms, and diagnosis was ascertained by direct immunofluorescence on bronchoalveolar fluids. None of the patients underwent seroconversion. This report draws attention to: (1) the fact that bacteriological filters do not ensure absolute security; (2) the need for frequent monitoring of the two factors governing legionella growth, water temperature and chlorination; and (3) the effectiveness of quinolones as a curative and prophylactic treatment of legionnaires' disease in transplanted patients avoiding pharmacological cyclosporin interaction.
A number of chronic pain syndromes in the perineal area can be related to pudental nerves suffering. The constancy of symptoms among various patients, and in duration for a particular one, alterations revealed by electrophysiologic studies, pain relief by diagnostic blocks, data from anatomic studies, preliminary results of medical and surgical applied therapies, give consistent arguments for possible organic lesions of pudental nerves.
The infratemporal fossa (ITF) is a hidden, subracranial part of the retrofacial region, which is concealed by the mandible. While its definition corresponds to bony relationships, it goes far beyond these. The classical pyramid with a lateral mandibular base and a superomedial apex, the pterygopalatine fossa, actually is a passage for the neurovascular elements it contains. It also is the hidden aspect of the manducatory apparatus, accommodating the pterygoid muscles. Besides these bony limits, the ITF has fasciomuscular boundaries formed posteriorly by the sphenomandibular ligament and the lateral insertion of the styloidian curtain on the angle of the mandible. The anterior limit, under the maxillozygomatic bones, is formed by the pterygomandibular ligament, on which spread the fibers of the buccinator muscle. The inferior limit is only theoretic and corresponds to the lower margin of the mandible. Within these limits, the ITF is connected with the mandible and the lateral manducatory muscles, the parotid gland, the peripharyngeal spaces, the submandibular region. However, it primarily is a passage into the neighboring regions with which it communicates through openings that are either endo- or exocranial, parotid, pharyngeal, nasal, orbital. Thus this fossa is one of the paths of the expansile processes that arise from the neighboring regions and invade it, being guided by the various anatomical openings we have described.
The modern imaging techniques (computed tomography, MRI), allow a new approach of the limits and contents of the infratemporal fossa. This better anatomical knowledge allows distinguishing three distinct subregions, hence providing better interdisciplinary understanding.
We report about one case of neurofibroma in the infratemporal fossa, which was treated surgically through a transzygomatic approach. Lowering the zygomatic arch with the masseter muscle and raising the coronoid process with the temporalis muscles provides a wide access to the infratemporal region without any mutilation. This way of approach can be widened anteriorly towards the orbital frame in order to reach lateral orbital lesions, and posteriorly towards the mastoideum to resect large tumors extending into the base of the skull. The transzygomatic approach seems to be particularly appropriate for the exeresis of benign tumors in the infratemporal region.
Twenty-nine patients with acute renal failure and multiple organ failure were treated with continuous arterio-venous or veno-venous haemofiltration for a period of 6 +/- 5 days. Sixteen of these patients were improved and haemofiltration was withdrawn, but secondary worsening occurred in 8 cases. The method is well tolerated by the cardiovascular system and provides a satisfactory metabolic control. The low patient's survival rate (27 percent) is due to the severity of the disease. In the absence of controlled studies, it is difficult to assert that continuous haemofiltration is better than conventional haemodialysis.
Carbohydrate-binding components were shown to be present at the surface of Listeria monocytogenes by means of a panel of neoglycoproteins using direct agglutination. These lectin-like components bind on neoglycoproteins bearing D-glucosamine, L-fucosylamine, or para-amino-phenyl-alpha-D-mannopyrannoside residues. The interactions were inhibited by the carbohydrate moieties specific to the neoglycoproteins. The protein nature of the lectin-like components of L. monocytogenes was ascertained by the loss of carbohydrate-binding capacity following protease treatment.
Two methods were compared for the isolation of the Toxoplasma gondii pellicle: centrifugation using a discontinuous sucrose gradient and affinity purification by microspheres activated with protein A. Electron microscopy showed that these two means of purification gave similar results, although better yields were obtained with the former than with the latter. Proteins of membrane fractions isolated using sucrose gradient were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Bands in the molecular-weight regions of 19, 22, 35, and 79 kDa appeared to be associated with the T. gondii pellicle.