Biomedical subjects

R Robert

Publications and source records attributed to R Robert.

At least 19 recordsLinked to original sources

PubMed2006

Large-scale production, bacterial localization assessment and immobilized metal affinity chromatography purification of a human single-chain Fv antibody against alphaIIb-beta3 integrin.

Our objective was to investigate the Escherichia coli localization (such as supernatant, cytoplasm and inclusion bodies) of an anti-alphaIIb-beta3 (alphaIIbbeta3) scFv fragment referred to as scFv[EBB3] produced in batch fermentation. Immobilized metal affinity chromatography (IMAC) purification was performed on supernatant using expanded bed absorbed technology (EBA) and on sonicated cells in native conditions over an immobilized copper-ion affinity column. Inclusion bodies were solubilized before IMAC purification and the refolding procedure was performed on the column. The majority of scFv[EBB3] were present as inclusion bodies (55%), whereas 36% were found in the cytoplasm and only 9% secreted in the supernatant. The scFv activity was assessed by enzyme-linked immunosorbent assay (ELISA), flow cytometry and immunohistochemistry analyses performed on a thrombus induced in vivo on an atherosclerotic rabbit model.

Animals↗

PubMed2006

[Co-infection with Mycobacterium tuberculosis and Pneumocystis jiroveci in a patient without HIV infection].

INTRODUCTION: Co-infection with Pneumocystis jiroveci and Mycobacterium tuberculosis is rarely reported in patients without HIV infection. CASE REPORT: We report the case of a 30 year old woman admitted to hospital for respiratory distress associated with a diffuse infiltrative pneumopathy. Corticosteroid therapy had been started two months earlier for suspected pulmonary sarcoidosis. Fibreoptic bronchoscopy and broncho-alveolar lavage produced evidence of Mycobacterium tuberculosis and cysts of Pneumocystis jiroveci. HIV serology was negative. Clinical progress was satisfactory following anti-tuberculous and anti-fungal therapy. CONCLUSION: Pneumocystis pneumonia is rare in subjects without HIV infection and is most often associated with a pathology or treatment leading to depression of cellular immunity. Corticosteroid treatment, even of short duration, presents the greatest risk. Systematic antibiotic prophylaxis should be considered in relation to the immune status of the patient. Co-infection with the tubercle bacillus as reported here is exceptionally rare.

Adult↗

PubMed2005

[An unusual diagnostic of quadriparesia: hyperkalemic paralysis. Report of four non-familial cases].

INTRODUCTION: The classical cause of hyperkalemic paralysis is the hereditary hyperkalemic paralysis. Very rarely, secondary forms of hyperkalemic paralysis have been reported. EXEGESIS: Four cases of acute paralysis mimicking Guillain-Barre syndrome in three cases and revealing severe hyperkalemia are presented. All the four patients had moderate chronic renal insufficiency. In two cases, the patients received spironolactone. One case was associated with lysis syndrome. All the 4 cases dramatically improved with the treatment of hyperkalemia. CONCLUSION: These cases pointed out the possibility for acute peripheral paralysis to reveal severe hyperkalemia.

Aged↗

PubMed2005

Improvement in production and purification bioprocesses of bacterially expressed anti-alphaIIbbeta3 human single-chain FV antibodies.

Production of anti-alphaIIbbeta3 (anti-alphaIIbbeta3)-binding single-chain FV (scFv) fragments obtained from combinatorial libraries of IgG human antibodies is of broad interest for imaging and treatment of acute coronary syndromes. The objective of our work was to design an optimized production of one selected anti-alphaIIbbeta3-binding scFv fragment for subsequent in vivo animal studies. Fed-batch fermentation was initiated with 2TY media supplemented with 0.1 M glucose. This growing batch culture was used as a starting point for further fed-batch induction, in which a media without glucose containing 1 mM IPTG and 0.4 M saccharose was continuously added. Subsequent purification was performed on the whole cell extract in native conditions over an immobilized copper-ion affinity column. The improved conditions allowed the recovery of 5 mg of highly purified scFv fragments as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The bioactivity of the scFv fragments was further monitored by ELISA, cytometric and immunohistochemical methods.

Animals↗

PubMed2005

[Dialysis-associated spondyloarthropathy. Case report and literature review].

Hemodialysis has considerably prolonged the life of patients suffering from terminal renal failure. However, long-term hemodialysis leads to new bone complications and spinal disorders such as destructive spondyloarthropathy (DSA). At the present time DSA is reported in 8% to 18% of the dialysed patients. Diagnosis is based on severe narrowing of the intervertebral disk, erosions and geodes of the adjacent vertebral plates simulating infectious spondylitis. Lesions progressively involve posterior joints and may lead to severe destruction of the spine. The pathogenesis of this syndrome is still unknown. Several factors have been implicated, including microcrystal deposition, amyloidosis, inflammatory and foreign body reactions and suggest that the pathogenesis of erosive spondyloarthropathies of hemodialysed patients is multifactorial. Spinal instability inducing myelopathy and radiculopathy were observed in 8% of the cases. Treatment must be accorded to the natural disease course and to the quality of the bone. We report the case of a chronic dialysed patient with destructive spondyloarthropathy involving the cervical and thoracic spine. Pathogenesis, radiological datas and therapeutic approach are discussed.

Adult↗

PubMed2004

Experimental assessment of new stent technologies: validation of a comparative paired rabbit iliac artery study model.

Preventing coronary in-stent restenosis is a major challenge for physicians and industry. To assess new stent technologies, a comparative paired iliac artery model in rabbits is proposed. One tubular stent was implanted in each external iliac artery in 12 rabbits (i.e., 24 stents). An artery overdilatation level of 20% was strictly observed. Restenosis was examined at 30 days by angiography, intravascular ultrasound (IVUS) examination, and histomorphometry. On quantitative angiography, the mean loss of angiographic diameter was 9.8 +/- 4.4% in the right as compared to 9.3 +/- 55% in the left artery (p = 0.75). On IVUS, the volume of intrastent neointimal proliferation was 26.6 +/- 4.9 mm(3) in the right and 25.8 +/- 3.5 mm(3) in the left artery (p = 0.58). In histomorphometry, the neointimal proliferation area was 0.78 +/- 17 mm(2) in the right and 0.76 +/- 0.17 mm(2) in the left artery (p = 0.87). Intrastent neointimal proliferation was comparable between the left and right arteries of all rabbits. The model has three main advantages: (1) arterial dilatation and thus arterial wall aggression are controlled, (2) pairing makes each animal its own control subject, and (3) the statistical power for comparative testing is maximized. The model enables the effect of a new drug-delivery device to be assessed.

Animals↗

PubMed2004

Oyster vasa-like gene as a marker of the germline cell development in Crassostrea gigas.

The oyster vasa-like gene was previously demonstrated to be specifically expressed in germline cells of adult oysters Crassostrea gigas. In the present study, this gene was used as a molecular marker to establish the developmental pattern of germline cells during oyster ontogenesis, using whole-mount in situ hybridization and real-time PCR. The Oyvlg transcripts appeared to be localized to the vegetal pole of unfertilized oocytes and maternally transmitted to embryos. At early development, these maternal transcripts were observed to segregate into a single blastomere, from the CD macromere of 2-cell stage to the 4d mesentoblast of blastula. From late blastula stage, the mesentoblast divided into two cell clumps that migrated to both sides of the larvae body and that would correspond to primordial germ cells (PGCs). Based on these results, we postulate that the germline of C. gigas is specified at early development by maternal cytoplasmic determinants including Oyvlg mRNAs, in putative PGCs that would differentiate into germinal stem cells in juvenile oysters.

Animals↗

PubMed2004

[Perineal pain].

The investigation of patients suffering from perineal pain when sitting led us to perform an anatomical study of the pudendal nerve. We dissected 50 cadavers and found areas of conflict for the nerve fibers. The nerve trunk can become entrapped at the level of the ischiatic spine, in the Alcock's canal and when it crosses the falciform process. Considering the clinical and neurophysiological data, this type of chronic pain may arise from compression of the nerve between the sacro-tuberal and the sacro-spinal ligaments, and/or in the fascia of the internal obturator muscle. Much like treatment of entrapment of the median nerve in the wrist, we decided to treat chronic perineal pain by nerve blocks, and later by surgery. We describe here the clinical symptoms, the neurophysiological data, and the technique of the nerve blocks. For patients with persistent pain, we propose a posterior surgical approach which has provided successful pain relief in two third of patients.

Female↗

PubMed2004

[Brindley technique with intradural deafferentation and extradural implantation by a single sacral laminectomy].

AIM: We propose an improved technique for implanting a sacral root stimulator associated with dorsal sacral rhizotomy ("Brindley's technique") in a single intra-sacral approach. METHOD: This novel technique only requires a single sacral laminectomy, consisting in a sacral deafferentation at the level of the dural cul-de-sac, facilitated by the anatomical identification of the sacral roots at this level. RESULTS: Four patients underwent surgery using this technique since October 2002, resulting in a very satisfactory micturition status. DISCUSSION: The aim of this technique, which is as rapid as the conventional intra-dural technique, is to obtain complete deafferentation and to induce non traumatic transdural motor stimulation at the same level. In this way, surgical goals can be reached more readily with greater safety than with other techniques.

Electric Stimulation↗

PubMed2004

[Cerebral venous thrombosis presenting as subarachnoid hemorrhage].

Headache of subacute onset, associated with other signs of increased intracranial pressure, represents the most frequent symptom of cerebral thrombophlebitis. We report a case of subarachnoid hemorrhage as a rare presentation of cerebral thrombophlebitis. Unfractionated intravenous heparin treatment resulted in resolution of subarachnoid hemorrhage on control brain CT scan and quick clinical recovery.

Adult↗

PubMed2004

[Chronic lower back pain: a new therapeutic approach].

Lower back pain is a common complaint of patients seen in our consultations. Despite progress, surgical procedures are still often unsuccessful in relieving pain. Blocks performed in the epidural spaces or more often in the articular facets have provided poor relief of chronic lower back pain. The pain has vegetative components. Considering anatomic findings, we describe the innervation of the peridiscal tIssues which suffer during degenarative conditions. We analyze the course of the autogenic nerves mediating lumbar pain, and select the site of the blocks necessary to obtain optimal selective pain relief. A well-defined block at the level of the communicating rami is described.

Clinical Trials as Topic↗

PubMed2003

What is the arcuate eminence?

A study was made of 100 homogeneous CT scans of the petrous part of the temporal bone to determine whether or not the arcuate eminence (AE) is a good landmark for the superior semicircular canal (SSCC) in the suprapetrous approach to the internal acoustic meatus which is used in the extirpation of acoustic neuromas. Direct measurements were made on consecutive coronal sections, 1 mm thick. The AE was absent from the petrous surface in 15% of cases. It corresponded to the relief of the SSCC in 37% of cases; laterally, however, it was separated from the petrous cortex by bone whose thickness varied from 0.5 to 5 mm. Finally, in 48% of cases, the AE was not a good landmark for the canal although nonetheless it participated in the development of this bulge in 46% of cases, always lying towards the medial border of the pneumatized eminence. In addition, study of the coronal sections with MRI allowed us to confirm that the AE does not routinely correspond to the imprint of a temporal sulcus. The AE, whose presence on the petrous surface is due to the combined effects of the SSCC, the air cells of the petrous part of the temporal bone and the temporal sulci, is only a good guide to the SSCC in 37% of cases and should not be considered as a reliable surgical landmark.

Humans↗

PubMed2003

Role of the sinu-vertebral nerve in low back pain and anatomical basis of therapeutic implications.

Low back pain is frequent and results in major disability for patients. This anatomical study was done to understand mechanisms involved in that pain. Two kinds of innervation are present in the lumbar spine: one depends on the somatic nervous system and the other on the sympathetic nervous system. The sympathetic nerves are the sinu-vertebral nerves and the rami communicantes which innervate the intervertebral disc, the ventral surface of the dura mater, the longitudinal dorsal ligament and the longitudinal ventral ligament. The sinu-vertebral nerve was described first by Luschka in 1850. This nerve is implicated in diffuse low back pain because of its pathway and its sympathetic component. This nerve cannot directly reach a somatic element at each level of the lumbar spine, so must first reach the L2 spinal ganglion. Thus, there is a "hole" in the somatic innervation between L3 and L5 because the dorsal nerves do not reach the skin at these levels. The pain therefore takes another route through the sympathetic system. Discogenic pain is mediated by the sinu-vertebral nerves, and through the rami communicantes reaches the L2 spinal ganglion. Anatomical and clinical features reinforce this hypothesis.

Cadaver↗

PubMed2003

Maternal Herpes simplex virus type 2 encephalitis following Cesarean section.

Herpes simplex virus type 2 (HSV-2) encephalitis is rare especially during pregnancy. In immunocompetent patients, HSV-2 meningitis (contrary to HSV-1 meningitis) is usually mild, without encephalitis. We report a rare case of maternal HSV-2 encephalitis following Cesarean section. The woman had no symptomatic genital lesion, and the infant was not infected. The route of meningeal infection (neuronal or hematogenous) is discussed.

Acyclovir↗

PubMed2003

[Ecology and transmission of Mycobacterium ulcerans].

Mycobacterium ulcerans is an environmental pathogen concerning mainly the tropical countries; it is the causative agent of Buruli ulcer, which has become the third most important mycobacterial disease. In spite of water-linked epidemiological studies to identify the sources of M. ulcerans, the reservoir and the mode of transmission of this organism remain elusive. To determine the ecology and the mode of transmission of M. ulcerans we have set up an experimental model. This experimental model demonstrated that water bugs were able to transmit M. ulcerans by bites. In insects, the bacilli were localized exclusively within salivary glands, where it could both multiply contrary to other mycobacteria species. In another experimental study, we report that the crude extracts from aquatic plants stimulate in vitro the growth of M. ulcerans as much as the biofilm formation by M. ulcerans has been observed on aquatic plants. Given that the water bugs are essentially carnivorous, it is difficult to imagine a direct contact in the contamination of aquatic bugs and plants. It seems very likely that an intermediate host exists. In an endemic area of Daloa in Côte d'Ivoire, our observations were confirmed.

Animals↗

PubMed2003

Improving selection of alphaIIbbeta3-binding phage antibodies with increased reactivity derived from immunized donors.

Although many studies of the immune response in polytransfused Glanzmann thrombasthenia (GT) patients and in autoimmune thrombocytopenic purpura (AITP) have demonstrated the frequent development of Abs directed against the alphaIIbbeta3 integrin, little is known about the induced anti-alphaIIbbeta3 autoantibodies at the molecular level. Phage display is a powerful technology for selecting and engineering mAbs expressed on the surface of filamentous bacteriophage. Combinatorial libraries of single-chain IgG were constructed from splenocytes from two patients with AITP and one patient with GT. In a previous study, activated platelets or alphaIIbbeta3-expressing CHO cells selection was performed to isolate human IgG anti-alphaIIbbeta3 binding fragments using combinatorial libraries created from the B cells of a GT and an AITP patient. However, we have experienced practical problems such as enrichment of truncated antibodies during selection. We decided to test prolonged treatments with elution agents after screening on the purified form of the alphaIIbbeta3 integrin activated with the RGD peptide. We obtained a higher percentage of clones with full-size antibody fragments as well as an enrichment of more specific alphaIIbbeta3-binding phage-Abs. Some of them, recognizing the activated form of the integrin, would be interesting to further study as potential diagnostic or therapeutic agents in acute coronary syndromes. Sequencing of selected phage-Abs revealed that they used different VH and VL genes with, for the majority of them, a high level of extensive hypermutations in the complementarity determining regions, indicating the diversity of the antigen-driven immune response that occurred in GT and AITP patients.

Animals↗

PubMed2003

Rapid identification of Candida glabrata with a new commercial test, GLABRATA RTT.

The GLABRATA RTT test (Fumouze Diagnostics, Levallois Perret, France) is based on the ability of Candida glabrata to hydrolyze trehalose but not maltose. It requires an inoculum of only four to six colonies, and the results are available within 20 min. We tested GLABRATA RTT with 330 stock isolates grown in subcultures on four different primary fungal isolation media and obtained a sensitivity of 94 to 98% (depending on the medium used) and a specificity of 97.3 to 98.6%. The false-positive results corresponded to C. tropicalis, C. famata, and C. lusitaniae. GLABRATA RTT thus offers rapid and reliable identification of C. glabrata.

Candida↗

PubMed2002

Partial return of motor function in paralyzed legs after surgical bypass of the lesion site by nerve autografts three years after spinal cord injury.

Spinal cord injuries often result in irreversible loss of motor and somatosensory functions below the lesion level. Treatment is limited to physiotherapy aimed at compensating disability. We previously showed that re-establishment of tissue continuity can be achieved in animal models through nerve autografts implanted between the rostral spinal ventral horn and the caudal ventral roots. Rostral motor neuron axons could thus reach peripheral targets, leading to some return of motor function. We used a similar approach in a paraplegic patient with stabilized clinical states three years after spinal cord traumatic damage at the T9 level. Three segments from autologous sural nerves were implanted into the right and left antero-lateral quadrant of the cord at T7-8 levels, then connected to homolateral L2-4 lumbar ventral roots, respectively. Eight months after surgery, voluntary contractions of bilateral adductors and of the left quadriceps were observed. Muscular activity was confirmed by motor unit potentials in response to attempted muscle contraction. Motor-evoked potentials from these muscles were recorded by transcranial magnetic stimulation. These data support the hypothesis that muscles have been re-connected to supra-spinal centers through motor neurons located in the rostral stump of the damaged cord. They suggest that delayed surgical reconstruction of motor pathways may contribute to partial functional recovery.

Electromyography↗