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Biomedical subjects

F Denis

Publications and source records attributed to F Denis.

At least 19 recordsLinked to original sources

A versatile shuttle cosmid vector for use in Escherichia coli and actinomycetes.

A shuttle cosmid vector has been constructed for Escherichia coli and actinomycetes. This vector, pFD666, utilizes the origin of replication (ori) of the broad-host-range plasmid, pJV1, from Streptomyces phaeochromogenes, for replication in actinomycetes and is compatible with vectors derived from pIJ101. The pFD666 vector employs the neomycin phosphotransferase-encoding gene (neo) from transposon Tn5 as the selective marker. To achieve this, the native promoter of neo was replaced by one optimized for expression in both hosts. The polylinker used for cloning has nine unique sites flanked by the promoters for T7 and SP6 RNA polymerase for the production of specific RNA probes. Terminators on both sides of the polylinker protect the vector from transcription originating from cloned inserts. An M13 ori allows the production of single-stranded DNA.

Actinomycetales

Shear fracture-dislocations of the thoracic and lumbar spine associated with forceful hyperextension (lumberjack paraplegia).

Twelve patients sustained a shear fracture-dislocation of their thoracic or lumbar spines by a hyperextension mechanism of injury. Ten male and two female patients were injured; their average age was 29 years (range, 22 months to 56 years). Ten fracture-dislocations occurred in the thoracic spine, one at the thoracolumbar junction, and one in the lumbar spine. Eleven patients had complete paraplegia, and one had incomplete paraplegia at the time of injury. Dural tears were found in six of the patients. Eleven patients were treated by posterior spinal fusion with instrumentation, and one was treated with a brace. Three patients were treated with Harrington distraction rods alone, six had Harrington distraction rods supplemented with a midline Harrington compression rod or interspinous wiring, and two were treated with Cotrel-Dubousset instrumentation. No patient was lost to follow-up. The average length of follow-up was 3.5 years (range, 1-9 years). Six of the patients treated with Cotrel-Dubousset instrumentation or Harrington distraction rods supplemented with either a midline compression rod or interspinous wiring healed anatomically; two patients developed pseudarthroses. None of the patients treated with Harrington distraction rods alone healed in an anatomic position. The use of Harrington distraction rods alone was associated with overdistraction and nonanatomic alignment of the spine. The disruption of the anterior stabilizing structures of the spine associated with hyperextension injuries necessitates the use of instrumentation that can stabilize the spine and prevent overdistraction. This injury can be successfully treated with Cotrel-Dubousset or Harrington distraction rods supplemented with either a midline compression rod or interspinous wiring.

Adult

[Bacterial endophthalmitis. Ophthalmological results of a national multicenter prospective survey].

Under the aegis of the GEEP (Groupement d'Etudes Epidémiologiques et Prophylactiques) a prospective multicentre study concerning bacterial endophthalmitis was carried out over a period of one year long with the contribution of 64 metropolitan ophthalmologic hospital departments. During this survey 143 cases of post surgical endophthalmitis were recorded: 111 of them were secondary to elective surgery, 32 developed after a perforating eye injury. Twenty-four cases of endophthalmitis developed in the absence of surgery were therefore called "medical" endophthalmitis. The frequency of endophthalmitis after elective surgery was 0.32%, and 2.8% after penetrating eye injury. Intraocular samples were obtained in 61.5% of the cases of post surgical endophthalmitis. 53 bacteria were isolated from 50 cases of endophthalmitis. The bacterial nature of the endophthalmitis was proved in 35% of these cases of post surgical endophthalmitis. Bacteria isolated from these cases of post surgical endophthalmitis were gram positive in 86.7%, and gram negative in 13.3% of cases. 20 bacteria were isolated from pseudophakic eyes: 10 of them were Staphylococcus epidermidis. The visual prognosis of endophthalmitis depends on the strain: visual acuity was more than 1/10 in 68% of cases of Staphylococcus endophthalmitis infection, but in only in 7% of cases of Streptococcus endophthalmitis infection. Intraocular injections of antibiotics both in the anterior chamber and in the vitreous, and vitrectomy increased the quality of the visual result. Three months after post surgical endophthalmitis, 35% of those eyes who received systemic and periocular antibiotic therapy, combined with intraocular antibiotics, with or without vitrectomy, recovered a visual acuity of 4/10 or more, instead of only 18% in the group without any intraocular therapy.

Adolescent

[Vertical transmission of HTLV-I].

Vertical transmission of the human T-cell leukemia type 1 (HTLV-1) from seropositive mothers to their offspring has been extensively studied. Transmission occurs mainly through breastfeeding. Prevention relies on screening pregnant women (and wet-nurses) for HTLV-1 antibodies and advising seropositive women to refrain breast feeding. Recently, antigen detection or genome detection (using PCR) studies on lymphocytes from neonates born to HTLV-1 positive mothers have established that prenatal vertical transmission does occur, although in only a small proportion of cases (0.5 to 7%). Studies on the HTLV-1 and improved understanding of its modes of transmission may provide new insight into the transmission of the HIV.

Cordocentesis

[Study of intraocular diffusion of ofloxacin in humans and rabbits].

The diffusion of ofloxacin in infected and healthy human and rabbit eyes was investigated. In the human study, cataract surgery patients were given intravenous ofloxacin either as a single 200 or 400 mg dose or as two 400 mg infusions 12 hours apart. Samples of aqueous humor and plasma were collected between 1 and 12 hours after the end of the infusion. Levels in the anterior chamber increased with the dose; peak levels, which occurred after three hours, were 0.33 mg/l after 200 mg and 1.24 mg/l after two 200 mg doses given 12 hours apart. In the rabbit study, 16 hours after experimental infection of the left eye by injection of S. epidermidis into the vitreous, animals were given an intraperitoneal injection of 20 or 50 mg/kg ofloxacin. Dosages in the various ocular tissues showed that penetration into the eye varied with race (albinos greater than pigmented) and dose. Intraocular ofloxacin levels, including in the vitreous, increased two fold when the eye was infected; however, penetration into the sclera, choroid, and retina was comparable in infected and noninfected eyes. These findings in humans and animals suggest that ofloxacin in a dose of a least 400 mg is a useful agent for the treatment of prophylaxis of ocular infections.

Aged

[Diffusion of piperacillin in the eye].

Intraocular diffusion of piperacillin was studied in 42 patients scheduled for cataract surgery (n = 35) or vitrectomy (n = 7). Piperacillin was administered intravenously (4 g/injection). Thirty-four patients were given a single dose and 8 were given two doses 12 hours apart. Peak piperacillin levels in the aqueous (7.3 mg/l) occurred one hour after the injection; levels in the vitreous were low (less than 0.6 mg/l). Intraocular diffusion of piperacillin was also studied in rabbits with an experimental Staphylococcus epidermidis infection of one eye; the other eye served as the control. In pigmented rabbits (6 Fauve de Bourgogne animals), increased diffusion and decreased elimination of piperacillin were seen in the aqueous, iris and cornea of the infected eyes, as compared with uninfected control eyes. In albino rabbits (6 New Zealand animals), results were less conclusive, with a difference between the infected and healthy eyes appearing only during the second hour following the injection. The good diffusion of piperacillin in the aqueous, especially in infected eyes (at least in rabbits), suggests that this drug may be useful for the treatment of ocular infections provided it is initiated early and given in combination with another antimicrobial exhibiting good intraocular diffusion.

Aged

Long-term evaluation of adolescents treated operatively for spondylolisthesis. A comparison of in situ arthrodesis only with in situ arthrodesis and reduction followed by immobilization in a cast.

The medical records and radiographs of forty-two adolescents (twenty-three male and nineteen female) who had had a posterolateral spinal arthrodesis for spondylolisthesis between 1950 and 1986 were reviewed to assess the long-term outcome of this form of treatment. The average age of the patients at the time of the operation was fourteen years (range, seven years and nine months to seventeen years and eleven months). The duration of the clinical and radiographic follow-up ranged from two years to twenty-seven years and seven months. All patients had an in situ arthrodesis of the involved vertebrae. Eighteen patients had no additional intervention, and twenty-four patients had reduction and application of a cast. Use of the cast led to a decrease in sagittal translation of more than 5 per cent in eighteen patients and a decrease in lumbosacral kyphosis (the slip angle) of more than 5 degrees in fourteen patients. Of the patients who did not have a cast, eight had an increase in sagittal translation of more than 5 per cent and ten had an increase in lumbosacral kyphosis of more than 5 degrees. There were no neurological problems at the time of the initial operation or after the reduction maneuver. At the most recent clinical follow-up examination, thirty-eight patients had no complaints of low-back pain or any restriction of work-related or recreational activities. Persistent low-back pain and pain in the lower extremities limited the activities of the remaining four patients, two of whom had another operation to alleviate these symptoms.

Adolescent

An improved aminoglycoside resistance gene cassette for use in gram-negative bacteria and Streptomyces.

A cloning cassette, carrying a modified amino-glycoside resistance gene (neo) from transposon Tn5 was constructed. Three restriction sites internal to the neo gene were eliminated by in vitro mutagenesis, allowing their use in designing new cloning vectors. The original, suboptimal transcription promoter was replaced with a synthetic sequence corresponding to the consensus for E. coli and Streptomyces promoters. The cassette has numerous restriction sites for easy subcloning of the promoter, the coding sequence or the whole gene.

Amino Acid Sequence

Seroepidemiology of human herpesvirus-6 in pregnant women from different parts of the world.

The prevalence of HHV-6 IgG was studied in 11 different countries across several continents: Morocco, Burkina-Faso, Congo, Ivory Coast, Mali, Niger, Senegal, Togo, Ecuador, Martinique, and France. The study group consisted of 550 pregnant women, representative of the general adult population in each country. Antibodies were detected by immunofluorescence assay on HSB-2 cells infected with HHV-6. Each serum was tested at nine dilutions (1:20 to 1:5,120), sera greater than or equal to 20 being considered positive. For the negative antigen control, we used mock-infected HSB-2 cells. Great differences were seen between separate areas: Morocco showed both low prevalence (20%) and a low geometric mean titer (12), whereas sub-Saharan Africa displayed high prevalences (60% to 90%) and variable geometric mean titers (34 to 229). This study revealed a prevalence of 92% for Ecuador, significantly higher than the prevalence for Martinique (50%), yet both countries had very low antibody titers compared with those found in Africa. The prevalence in France (76%) was similar to previous results from other European countries.

Adult

Specificity of new peptide immunoassays versus other immunoassays and agglutination tests for detection of HIV antibody in African sera.

The specificity of three HIV EIAs using synthetic peptides was evaluated and compared with that of four commercial EIAs using recombinant proteins or whole virus lysates of HIV-1 or of HIV-1 and HIV-2, and of two tests based on agglutination of sensitized particles. A total of 734 West African sera were screened. The best results were obtained with tests using recombinant proteins. HIV tests using synthetic peptides able to distinguish between HIV-1 and HIV-2 antibodies showed comparable specificity, but some false negative results represent a major handicap of these peptide EIAs in screening for HIV antibodies.

Agglutination Tests

[The axial orientation of the phalanges following the curling up of the fingers].

This study follows and modestly completes those by Dubousset and Kapandji concerning the phenomena of axial (or longitudinal) rotation of the phalanges combined with flexion-extension of the fingers. Our analysis of the orientation of axial rotation of the skeletal elements of the digital chain, in relation to each other and during digito-palmar flexion was supported by simple observation, impressions in silicone paste, study of anatomical preparations, three-dimensional computed tomography. The index finger and middle finger tend to supinate. The ring finger undergoes virtually no rotation and the distal end of the little finger tends to pronate. These phenomena, essential for good adaptation to grip and fine manipulation must be taken into account by rehabilitation physicians when the amplitude of these movements are limited by immobilisation or disease.

Adult

Seroepidemiology of human T-cell lymphotropic virus type I/II in Benin (West Africa).

In 1988-1989, a national survey was conducted in Benin to determine the distribution of HTLV-I infection in a representative sample of adult individuals. This study comprised 2625 healthy subjects recruited in the six provinces of Benin and 1300 blood donors from Cotonou and from the other five provinces. Sera were screened for HTLV-I antibody by both immunofluorescence (IF) and enzyme immunoassay (EIA). Sera positive or doubtful by at least one technique were further analyzed by Western blot and radioimmunoprecipitation assay (RIPA) when indeterminate. Samples were considered as positive if they reacted with two gene products. No blood donor was positive. Over the 2625 subjects, 39 (1.5%) were positive. We observed a statistical difference between male and female (1%, 2%, p less than 0.05). A difference was also observed according to the areas studied: the HTLV-I antibody rate increased from coastal (0.3%) to northern (5.4%) provinces. HTLV-I seroprevalence increased significantly with age. This survey shows that HTLV-I infection exists in Benin but varies according to regions.

Adult

Site-directed serology using synthetic oligopeptides representing the C-terminus of the external glycoproteins of HIV-1, HIV-2, or SIVmac may distinguish subtypes among primate lentiviruses.

In this study the presence of a highly immunogenic domain located at the C-terminus of the external glycoproteins (EGP) of human and simian immunodeficiency viruses (HIV-1, HIV-2, and SIVMAC) is shown using synthetic oligopeptides as antigens in enzyme immunoassays. This epitope is probably located within the last 13 and 15 residues of the EGP of HIV-1 and HIV-2, respectively. The C terminal epitope of the EGP of SIVMAC may involve residues located more upstream. Among the HIV-2/SIV serotype, we observed that the reactivity to the C-terminal epitope of gp120 was dependent of both species and geographical origin of the samples tested. It seems that this gp 120 C-terminal epitope could distinguish subtypes among the HIV-2/SIV serotype. Further studies, using site-directed enzyme immunoassays with synthetic peptides representing the C-terminus of the EGP derived from a wide variety of HIV2/SIV strains must be performed to confirm this observation. These kinds of assays may constitute important tools for use in seroepidemiological studies and broaden our understanding of the distribution and phylogenetic relationship of primate lentiviruses.

Amino Acid Sequence

Luque-Galveston procedure for correction and stabilization of neuromuscular scoliosis and pelvic obliquity: a review of 68 patients.

Sixty-eight patients with neuromuscular spine deformity were treated by posterior spine fusion with Luque-Galveston instrumentation between 1982 and 1986. The minimum follow-up was 4 years. Diagnoses included cerebral palsy in 34 patients and other neuromuscular diseases in another 34 patients. The average age was 14 years. Twenty patients also had anterior spine fusion without instrumentation. Preoperatively the average scoliosis was 73 degrees and this was corrected to 33 degrees at final follow-up. The subgroup having anterior discectomy and fusion had a more severe scoliosis and pelvic obliquity, but the percent of correction was similar to that of the group with posterior reconstruction only. Twenty-four patients who had an associated significant sagittal plane deformity were corrected to a physiologic curvature. A postoperative thoracolumbosacral orthosis was used in 27 patients, and a molded seating orthosis was used in 18. Although the rate of complications was high (62%), most of them were minor. Instrumentation problems occurred in 14 patients (21%), only 4 of them having broken rods. There were no broken wires. Pseudarthrosis occurred in seven patients (10%). Three patients had minor neurologic deficits, all transient. The "windshield-wiper" sign was defined as any radiolucency of 2 mm or greater. Twenty-six patients had this sign at follow-up, and this group had a higher percentage of complications, but the existence of this sign did not necessarily indicate a problem.

Adolescent

The subclass distribution of IgG autoantibodies in cicatricial pemphigoid and epidermolysis bullosa acquisita.

To study the subclass distribution of autoantibodies and their complement-fixing capacity in cicatricial pemphigoid (CP) and epidermolysis bullosa acquisita (EBA) we studied the sera from 23 patients by both indirect immunofluorescence (IIF) on 4-microns cryostat sections of normal human skin and immunoblotting of epidermal or dermal extracts. Monoclonal antibodies of strict specificity for human IgG subclasses were used. Sera from 20 patients with BP served as controls. In addition, total IgG subclass levels were determined by indirect competitive ELISA in all sera. Complement binding capacity was studied by IIF using antibodies to C3 after incubation of skin section with autoantibodies and source of fresh complement. CP autoantibodies reacting with the 230-240 kD and/or the 180-kD epidermal bands showed an IgG4/IgG1 subclass restriction, with a predominance of IgG4 in 10 cases, of IgG1 in four. In BP sera, IgG4 and IgG1 autoantibodies were detected with a similar frequency (100% and 83%, respectively). In EBA sera, autoantibodies reacting with the 290 kD and 145 kD dermal bands also showed an IgG1/IgG4 restriction. Concordant results were obtained by IIF. However, the IIF method had a lower sensitivity for the detection of IgG4 CP antibodies and IgG1 EBA antibodies than immunoblotting. Finally, when CP antibodies were analyzed for their complement-binding activity, it was found that sera containing IgG4 autoantibodies alone never fixed complement whereas all complement-fixing CP sera had IgG1 autoantibodies, suggesting that only this subclass of antibodies is capable of fixing complement.

Aged

Fine serotyping of human immunodeficiency virus serotype 1 (HIV-1) and HIV-2 infections by using synthetic oligopeptides representing an immunodominant domain of HIV-1 and HIV-2/simian immunodeficiency virus.

In this study, enzyme immunoassays for detection of type-specific antibodies to human immunodeficiency viruses (HIV) were developed by using short peptides corresponding to sequences located within the immunodominant domain of the transmembrane glycoproteins of both HIV-1 and HIV-2-simian immunodeficiency virus (SIV). The assays were highly sensitive with currently available sera from various geographical areas. Furthermore, they appeared to be more specific in HIV serotyping than the Western blot (immunoblot) assay, since all of the sera were clearly discriminated as one or the other type. It was also shown that in contrast to HIV-1, the C-terminal cysteine residue (amino acid 620, SIV from captive macaques, Mm142 strain) of the HIV-2-SIV peptide is not necessary for recognition of the peptide by antibody to HIV-2.

Amino Acid Sequence