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Biomedical subjects

R Robert

Publications and source records attributed to R Robert.

At least 127 records · Page 7Linked to original sources
PubMed1990

Structures involved in the binding of human fibrinogen to Candida albicans germ tubes.

Recent evidence for the interaction between human fibrinogen and Candida albicans germ tubes have led us to attempt to characterize the structures involved. Using 125I-radiolabeled proteins, fibrinogen purified by affinity chromatography and its plasmin degradation products, the binding sites on the fibrinogen molecule appeared to be located specifically in the D-domain. Conversely to the fibrinogen and the fragment D, radiolabeled fragment E, however, did not interact with cells. The binding was time-dependent, saturable and reversible. Scatchard analysis of the data obtained revealed an average of 6000 binding sites per germ tube with dissociation constant (Kd) of 5.2 X 10(-8) M. No potent competition was observed for a range of different proteins and carbohydrates. Fibrinogen fragment D binding proteins were identified using a dithiothreitol-iodoacetamide extract of the fungus. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting, one component of 68 kDa was detected. Thus, the presence of fibrinogen binding proteins specifically localized on the cell wall surface of C. albicans germ tubes may constitute one of the factors involved in the development of candidosis.

Binding Sites↗
PubMed1990

Laminin receptors on Candida albicans germ tubes.

Recent evidence for the role of laminin in cell adhesion and in the pathogenesis of several bacterial infections has led us to investigate the existence of receptors for this extracellular matrix component in Candida albicans. At first, immunofluorescence demonstrated the presence of laminin-binding sites at the surface of germ tubes. Electron microscopy confirmed this result and permitted precise localization of the binding sites on the outermost fibrillar layer of the germ tube cell wall. By using 125I-radiolabeled laminin, the binding was shown to be saturable and specific, hence demonstrating characteristics of true receptors. Analysis of the data by the Scatchard equation indicated that there were about 8,000 binding sites per cell, with a dissociation constant (Kd) of 1.3 x 10(-9) M. Binding was inhibited by prior heating or trypsinization of cells. Furthermore, of the different proteins and carbohydrates tested in competition experiments, only fibrinogen greatly reduced the laminin binding. Finally, dithiothreitol and iodoacetamide treatment of germ tubes allowed us to identify the laminin receptors through analysis of this extract by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblotting. Two components, of 68 kilodaltons and a doublet of 60 and 62 kilodaltons, were detected. Thus, C. albicans possesses germ tube-specific surface receptors for laminin which could mediate its attachment to basement membranes and so contribute to the establishment of candidiasis.

Candida albicans↗
PubMed1990

Evaluation of a new bicolored latex agglutination test for immunological diagnosis of hepatic amoebiasis.

A new bicolored latex agglutination amoeba test (BLA) for detection of antibodies against Entamoeba histolytica was evaluated for its practicability and diagnostic sensitivity and specificity. BLA is rapid (5 min) and simple to perform. It requires only 20 microliters of a 1/3-diluted serum, 17 microliters of reagent, and a glass slide. Reading of the test is easy because a positive result shows a green spot with a red surrounding edge. This bicolored pattern is easily distinguishable from the negative test result, which shows a homogeneous dark-brown spot. By using serum samples from 348 individuals, BLA was compared with immunofluorescence assay, indirect hemagglutination, and counterimmunoelectrophoresis. Sensitivity, specificity, efficiency, and positive and negative predictive values of the four methods were almost identical. The results of this study indicate that BLA could be very useful both as a screening method for the diagnosis of invasive amoebiasis and for epidemiological purposes.

Amebiasis↗
PubMed1990

[Neuralgia of the pudendal nerve. Anatomo-clinical considerations and therapeutical approach].

The anatomic study of the pudendal nerve and its relation allows an approach of the mechanisms of compression likely to engender perineal neuralgia. Two conflictual zones are isolated: the first is linked to the clamp which is produced by the insertion of the sacro-epinous ligament on the ischial spine and the sacro-tuberal ligament; the second is linked to the falciform process of the sacrotuberal which threatens the nerve by its sharp upper edge. This conflict is particularly acute in a sitting position. The relation between the trunk of the nerve, its branches and these zones of conflict may explain the clinical observations. The electrophysiological investigations (detection of neurogenic muscles of the perineal floor. Increased sacral latency, pudendal nerve terminal motor latency) confirm the diagnosis. The anesthetic blocks of the pudendal nerve on the ischial spine only have a complimentary diagnostic value. The peridural blocks may also have an interesting therapeutic action (60% of good results 3 months later). In some persistent cases, the nerve has been decompressed firstly by perineal approach, but latterly by transguteal approach.

Electrophysiology↗
PubMed1990

[Postoperative analgesia for circumcision in children].

Circumcision in children is followed by severe pain. This study analysed retrospectively anesthetic techniques of 110 children from 17 months to 14 years old who had undergone ambulatory of 24 h stay circumcision. There were two groups of patients: one being operated on under locoregional techniques combined with general anesthesia (53.6%), the other one under general anesthesia alone (46.4%). Post operative analgesia was provided by the regional anesthesia (with or without additional analgesics via rectal route) for the former group whereas analgesic drugs were administered only rectally for the latter one. In this second group, pain relief assessment was insufficiently recorded and was considered poor. In the first group, dorsal nerves block of the penis (DNBP) was performed on 47 children (79.8% of the locoregional techniques), caudal block on 10 patients and ring block on 2 patients. Regional techniques offered a satisfactory, safe and reliably effective post circumcision analgesia. DNBP should be used systematically in order to shorten duration of day circumcision stay.

Administration, Rectal↗
PubMed1990

[Intramuscular methohexital. A simple and reliable means of sedation for cerebral computed tomography in children].

Intramuscular methohexital sedation was retained as an easy and reliable method to sedate children for a C.T. scan. In this retrospective study of 50 cases of children aged from 2 months to 7 years all the children were administrated an oral premedication (diazepam: 1 drop/kg and atropine: 0.02 mg.kg-1) one hour before the scanner examination. Once in the operating room, they were administrated 10 mg.kg-1 methohexital saline 2.5% solution, intramuscularly deep in the buttock. E.C.G. was the main monitoring. Spontaneous breathing was evidenced by means of a simple device. At the end of the scan, the child was taken care for in the recovery room. The methohexital dose provided adequate sedation in most cases. Once the injection was given, a motionless state was reached in 4.20 minutes. The insertion of an intravenous catheter induced movements in 96% cases, which did not interfere with the successful intravenous puncture. In 33% cases, 1 to 2 mg.kg-1 ketamine was necessary because of a failed attempt at obtaining the required state, or of an awakening due to iodized injection. Among those cases, half the children were overweight for their ages. In this situation an adjusting dose should be considered. On average, a child under the influence of the drug slept for 35 minutes and the required time for a C.T. scan is 23.3 minutes. Time in the recovery room is on average 20 minutes. There was no episode of cardiovascular or respiration failure, or local reaction at the injection site. There was also no episode of seizure.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1989

Severe hypoxemia in a case of midgut carcinoid tumor.

A 33-year-old woman treated for carcinoid tumor developed severe hypoxaemia. This hypoxaemia may have been related to an extracardiac right-to-left shunt. The pathogenic role of vasoactive agents is discussed and comparisons made with cirrhosis-associated hypoxaemia.

Adult↗
PubMed1989

The infratemporal fossa: a trial clarification.

The contents of the infratemporal fossa have been studied using CT scans, anatomical dissections and radiography of the anatomical specimens. On the strength of this, 3 distinct regions are discernable: the anterior part of the fossa contains the fat pad of the cheek and this area corresponds to the retromaxillo-zygomatic region; the region of the pterygoid m. contains vascular structures and lies behind the preceding region; the pterygopalatine fossa, formerly considered the deepest part, extends the infratemporal fossa superiorly and medially. These anatomical and radiographic findings could serve as a guide to maxillo-facial surgeons dealing with expanding lesions within the infratemporal fossa, or invading it from adjacent regions.

Adipose Tissue↗
PubMed1989

Reflections on the mechanical structure of the base of the skull and on the face. Part 1: Classical theories, observed structures.

Using thick sections of the base of the skull and face their mechanical structure is viewed from the engineering aspect and the anatomic solutions evolved are compared with those selected by Aerospatiale engineers for the concept and development of the Airbus. It is concluded that the anterior and middle cranial fossae, together with the face, constitute an inseparable mechanical assembly each of whose component units participate in the rigidity of the others. Since this mechanical assembly must provide maximal rigidity for minimal weight, this suggests that aeronautical solutions should throw much light on the detail of construction of the skull and face. Indeed, the rigidity and lightness of the latter are obtained by means of solutions familiar in aeronautics: the reliance on thin-shelled beams with a honeycomb filling, the diploe analogous to a preconstrained composite or sandwich structure, a system of frames, struts and stiffeners, and the use of fillets at the sites of junction of struts.

Biomechanical Phenomena↗
PubMed1989

Chlorophacinone intoxication. A biological and toxicological study.

Plasma chlorophacinone determinations were performed in three cases of intoxication. The data collected in this study confirm the particularly prolonged anticoagulant effect of this compound and show that the knowledge of plasma concentrations may be very useful for clinicians since it allows to confirm the diagnosis and to evaluate the duration of the treatment. The determination of half-lives was investigated and the results indicate that the greater the quantity absorbed, the longer the half-life. The effect of phenobarbital on the elimination of cholorophacinone could be studied in one case. An increased elimination was noted when phenobarbital was administered.

Adult↗
PubMed1989

[Clinical, neurophysiologic and therapeutic remarks from anatomic data on the pudendal nerve in some cases of perineal pain].

Clinical observations in patients suffering from positional perineal pain have led us to performing an anatomical study of the pudendal nerve in order to demonstrate compression of this nerve trunk by elements likely to compress it in the sitting position. Thus we observed that the falciform process of the sacrotuberous ligament may act in this way. Besides helping us to understand the clinical symptoms, this anatomical study allowed choosing the technique we found most appropriate for the anatomical conditions observed out of the various neurophysiological examinations described in the literature. Lastly, we describe the surgical technique that allows releasing the trunk of the pudendal nerve under an operating microscope.

Evoked Potentials, Somatosensory↗
PubMed1989

[Cephalhematoma infection in neonatal septicemia].

Most cephalhematomas resorb spontaneously; intervention by means of needle aspiration may introduce infection. In our case, a neonatal septicemia was associated with a large parietal cephalhematoma. The newborn was discharged after treatment of sepsis. Three days later, the diagnosis of infected cephalhematoma was apparent, associated with meningitis and septicemia. The authors discuss the physiopathology of the infection, antimicrobial therapy and careful aspiration when a serious infection is associated with cephalhematoma.

Cerebral Hemorrhage↗
PubMed1989

Dynamic changes of the cell wall surface of Candida albicans associated with germination and adherence.

The distribution of mannoproteins at the cell wall surface of Candida albicans was analyzed during the process of germination in conditions favoring adherence of germ tubes to a plastic matrix. Three cytochemical methods allowing the detection of concanavalin A binding sites, anionic sites and the enzyme acid phosphatase, respectively were used. All three methods gave similar results, indicating a spatial and temporal reorganization of some cell wall mannoproteins: a strong labeling was observed on blastoconidia; in contrast, as soon as the emergence of germ tubes took place, these reactions decreased dramatically at the surface of mother cells, whereas the germ tube surface was strongly stained. Some new components with multiple biological activities were detected at the germ-tube surface. Indeed, among mannoproteins responsible for an enhanced adhesion to plastic surfaces, two components with molecular weights of 68 and 60 to 62 kDa were shown to interact with laminin, fibrinogen, and C3d. This study therefore indicates that germination, and then adherence of germ tubes, imply a degradation of surface mannoproteins, and a simultaneous presentation of new molecules which can interact with their nonbiological materials or host proteins.

Acid Phosphatase↗