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Biomedical subjects

L Simon

Publications and source records attributed to L Simon.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Treatment with danaparoid during pregnancy for a woman with a cutenous allergy to low-molecular-weight heparin] .

The authors describe a case of heparin-induced skin reaction due to two preparations of low molecular weight heparin in a pregnant woman. The main characteristics of heparin-related cutaneous allergy are reported. The use of an heparinoid, usually indicated for patients with heparin-induced thrombocytopenia, appeared to be efficient and safe for the mother and her fetus. An epidural analgesia was performed for labor analgesia, 24 hours after the last injection of danaparid of sodium.

Adult↗
PubMed2000

Effect of injection rate on hypotension associated with spinal anesthesia for cesarean section.

Maternal hypotension is a common problem during cesarean section under spinal anesthesia. We evaluated in a prospective observational study the influence of injection speed on maternal hypotension. Hyperbaric bupivacaine 10 mg, sufentanil 2 microg and morphine 200 microg (total volume 4 mL) were injected either quickly (<15 s) or slowly (=120 s) in 50 women scheduled for elective cesarean section. Hypotension (systolic arterial pressure (SAP) <100 mmHg or <70% of baseline) was promptly treated with 5 mg ephedrine boluses. Slow injection significantly reduced the incidence of hypotension (68% in the 120 s group and 92% in the other, P =0.03). In addition, onset of hypotension was delayed, had a shorter duration and required less ephedrine for hypotension in the 120 s group (11.6 mg vs. 19.6 mg, P =0.019). Anesthesia was satisfactory for all women. We conclude that a 2 mL/min injection rate may be a simple and effective way to reduce the incidence and severity of hypotension during cesarean section under spinal anesthesia.

Journal Article↗
PubMed2000

Vesicle-mediated transfer of virulence genes from Escherichia coli O157:H7 to other enteric bacteria.

Membrane vesicles are released from the surfaces of many gram-negative bacteria during growth. Vesicles consist of proteins, lipopolysaccharide, phospholipids, RNA, and DNA. Results of the present study demonstrate that membrane vesicles isolated from the food-borne pathogen Escherichia coli O157:H7 facilitate the transfer of genes, which are then expressed by recipient Salmonella enterica serovar Enteritidis or E. coli JM109. Electron micrographs of purified DNA from E. coli O157:H7 vesicles showed large rosette-like structures, linear DNA fragments, and small open-circle plasmids. PCR analysis of vesicle DNA demonstrated the presence of specific genes from host and recombinant plasmids (hly, L7095, mobA, and gfp), chromosomal DNA (uidA and eaeA), and phage DNA (stx1 and stx2). The results of PCR and the Vero cell assay demonstrate that genetic material, including virulence genes, is transferred to recipient bacteria and subsequently expressed. The cytotoxicity of the transformed enteric bacteria was sixfold higher than that of the parent isolate (E. coli JM109). Utilization of the nonhost plasmid (pGFP) permitted the evaluation of transformation efficiency (ca. 10(3) transformants microg of DNA(-1)) and demonstrated that vesicles can deliver antibiotic resistance. Transformed E. coli JM109 cells were resistant to ampicillin and fluoresced a brilliant green. The role vesicles play in genetic exchange between different species in the environment or host has yet to be defined.

Animals↗
PubMed2000

[RS3PE syndrome: report of 11 cases].

The RS3P syndrome or remitting seronegative symmetrical synovitis with pitting oedema, was described in 1985 by McCarty. The description refers to a rheumatologic set of symptoms with an acute commence, with no erosive lesions, with seronegativity, affecting more frequently to elderly males and showing an excellent prognosis. These characteristics make it possible to difference from the rheumatoid arthritis and from the rheumatic polymyalgia. We present eleven cases which confirm the good prognosis already described, but we suggest the possibility of this syndrome could be a manifestation or the beginning of other possible diseases.

Aged↗
PubMed2000

[Nosocomial infections in mother and child: specific risks in the labour ward].

Nosocomial infection is a frequent and potentially lethal complication in obstetrics. The incidence of this complication may be underscored and an accurate surveillance system must be used in each obstetrics unit for infection control. This surveillance system should also identify the patients at risk for infection in order to improve prevention efforts. beta-lactam-sensitive streptococcus is often involved in obstetrical infections and a short antibio-prophylaxis is indicated in most obstetrical procedures. Disinfection strategy, guidelines for clinical practice and control charts should be established in each obstetrics unit to prevent nosocomial infections.

Anesthesia, Obstetrical↗
PubMed2000

Morphometric analysis of dendritic tree of cerebellar Purkinje-cells.

Basic neural processes of sensorimotor adaptation can be observed by cellular-level studies on cerebellar cortex, both by electrophysiological and morphological means. In earlier studies we demonstrated double (sometimes triple or quadruple) rhythmic prespike activity patterns in dendritic microelectrode records taken from cerebellar Pc. By their active and passive interactions, the actual input pattern will turn into an arrhythmic output spiking, realizing a nonlinear and phase-sensitive integration. This curious complex spike-generating process can give rise to novel cerebellar functional models. The acting membrane dynamics rely not just upon the ionic current machinery but also upon the specific micromorphology of the dendritic tree, especially that of the branching areas. Although, statistical analyses on Pc dendrites generally followed the graph-theory, elaborated abstract parameters for complexity and hierarchy, and denied realistic geometry. Thus a novel specific morphometric study should be carried out, first applied to the main branching sites.

Animals↗
PubMed1999

Comparative study of the neuronal plasticity along the neuraxis of the vibrissal sensory system of adult rat following unilateral infraorbital nerve damage and subsequent regeneration.

The aim of the present study was to examine the physiological consequences of a unilateral infraorbital nerve lesion and its regeneration at different levels of the somatosensory neuraxis. In animals whose right infraorbital nerve had been crushed, a large unresponsive area was found in the main brainstem trigeminal nucleus (Pr5). Responses evoked by ipsilateral vibrissal deflection in the middle of Pr5 reappeared only on days 22-35 after the nerve had been transected, whereas recovery from the nerve crush took only 7-9 days. However, no sign of short-term neuronal plasticity was observed in Pr5 after peripheral nerve injury. An enlargement of the receptive fields in two-thirds of the units and a lengthening in the delay of the evoked responses were observed as long-term plastic changes in Pr5 neurons after peripheral-nerve regeneration. In the ventral posteromedial nucleus of the thalamus (VPM) of partly denervated animals, however, only minutes or hours after the nerve crush, certain units were found to respond in some cases not only to the vibrissae, but also to mechanical stimulation of the face over the eye (two units), the nose (one unit), and the midline (one unit). Apart from the experiments involving incomplete denervation, the vibrissal representation areas of the VPM were unresponsive to stimulation of both the vibrissae and other parts of the face until nerve regeneration had occurred. In the somatosensory cortex, an infraorbital nerve crush immediately resulted in a large cortical area being unresponsive to vibrissal deflection. It was noteworthy, however, that shortly after the nerve crush, this large unresponsive whisker representation cortical area was invaded from the rostromedial direction by responses evoked by stimulation of the forepaw digits. In spite of the reappearance of vibrissa-evoked responses 7-10 days after the nerve crush, an expanded digital representation could still be observed 3 weeks after the nerve crush, resulting in an overlapping area of digital and vibrissal representations. The withdrawal of the expanded representation of forepaw digits was completed by 60 days after the nerve crush. The results obtained in Pr5, the VPM, and the cortex strongly suggest that the higher the station in the neuraxis, the greater the degree of plasticity after infraorbital nerve injury.

Animals↗
PubMed1999

[Dural taps in peridural analgesia for labor: management by French anesthesiologists in 1997].

OBJECTIVES: To assess prophylactic and curative managements of dural taps occurring during the setting of epidural analgesia (EA) for labour. STUDY DESIGN: Nationwide French retrospective survey. PATIENTS AND METHODS: From April to July 1997, a questionnaire was sent to 799 French obstetrical units located in both teaching and non-teaching public hospitals and private institutions. RESULTS: Answers were obtained from 267 units (response rate of 33%). Although management of dural taps was similar in 52% of the institutions, only 8% had produced a written protocol. After a dural puncture, EA was still performed in 95% of the units, but usually in another interspace (87%). Large oral fluid intake was the most frequent prophylactic measure (81%). To prevent postdural puncture headache (PDPH), bed rest was largely used (76%) and lasted 24 hours in 46% of the institutions. Prophylactic epidural blood patch (EBP) was performed in 14% of the units. To treat PDPH, a majority of anaesthesiologists performed an EBP (92%) and most of them after a delay of 48 hours (62%). Intravenous and oral caffeine was used in 31 and 24% of the units respectively. Prior to EBP, coagulation status was assessed in about 20% of the units and blood culture in less than 3%. In 65% of the units the injection of EBP was discontinued when the patients felt backache. A large range of volumes were injected, but usually less than 20 mL were administered (81%). In 60% of the units the patients were discharged home after an overnight stay in the hospital. If the first EBP failed, a second one was performed in 61% of the cases. CONCLUSION: Management of dural taps occurring after EA for pain relief in labour differs widely from one French obstetrical unit to another.

Anesthesia, Epidural↗
PubMed1999

[Intratracheal intubation without muscle relaxant with the use of remifentanil-propofol].

OBJECTIVES: To assess tracheal intubation conditions after induction of anaesthesia with remifentanil and propofol, using itemized scoring criteria. STUDY DESIGN: Clinical, prospective, open, non comparative trial. PATIENTS: One hundred consecutive patients undergoing surgery not requiring muscle relaxation, during the study period extended over 12 months. METHODS: After premedication with lorazepam (2 mg) the day before and hydroxyzine (100 mg) one hour before surgery, anaesthesia was induced with remifentanil administered continuously with a syringe pump at a rate of 1.20 +/- 0.06 micrograms.kg-1.min-1 and propofol (3 mg.kg-1 IV bolus). The trachea was intubated two minutes later and mouth opening, glottis exposure, glottis opening, movements, additional anaesthetic agents and chest rigidity were recorded. RESULTS: Intubation conditions were excellent in 87% of patients, and the tube was inserted rapidly, within two minutes. However in 38% of patients the cuff inflation caused cough. In 13%, glottis opening was delayed and intubation required three minutes. A major decrease of arterial pressure and heart rate was recorded in 9 and 6% of patients respectively. CONCLUSION: Induction of anaesthesia using remifentanil and propofol allows satisfactory tracheal intubation without a muscle relaxant. However this technique is contraindicated: a) in patients with a full stomach, as intubation is not always successful at the first attempt; b) in patients scheduled to undergo neurosurgery or ophthalmic surgery, as tracheal intubation may elicit cough, increasing intra-cranial and intra-ocular pressure; c) in patients in poor circulatory status, as it decreases significantly arterial pressure and heart rate.

Anesthesia, Intravenous↗
PubMed1999

Stereotypes and terror management: evidence that mortality salience enhances stereotypic thinking and preferences.

If stereotypes function to protect people against death-related concerns, then mortality salience should increase stereotypic thinking and preferences for stereotype-confirming individuals. Study 1 demonstrated that mortality salience increased stereotyping of Germans. In Study 2, it increased participants' tendency to generate more explanations for stereotype-inconsistent than stereotype-consistent gender role behavior. In Study 3, mortality salience increased participants' liking for a stereotype-consistent African American and decreased their liking for a stereotype-inconsistent African American; control participants exhibited the opposite preference. Study 4 replicated this pattern with evaluations of stereotype-confirming or stereotype-disconfirming men and women. Study 5 showed that, among participants high in need for closure, mortality salience led to decreased liking for a stereotype-inconsistent gay man.

Adult↗
PubMed1999

Central venous catheter placement in children: evaluation of electrocardiography using J-wire.

Misplacement of a central venous catheter may lead to myocardial perforation and dysrhythmia. Atrial electrocardiography (ECG) through a saline column is an effective but complex method to determine the accurate location of catheters. We evaluated a simplified variant of this technique using the guidewire as an internal electrode in 23 children (5-16 years old) undergoing spinal surgery. Catheters were placed using a Seldinger technique after jugular or subclavian venous puncture. Each time the operator recognized the atrial signal, the catheter was found to be correctly placed on the chest radiograph (20/23). In three patients, the atrial signal was not obtained. A technical error was responsible in one case whereas the two others were related to aberrant migrations of the catheter either into a subclavian vein or into the pleura. In this latter case, the complication was unrecognized on the first radiograph despite malposition having been predicted by atrial ECG. We conclude that a method using atrial ECG guidance is sensitive and specific, and may be an alternative to the classical chest radiograph to detect accurate placement of central venous catheters in children.

Catheterization, Central Venous↗
PubMed1999

Sound propagation in urban areas: a periodic disposition of buildings.

A numerical simulation of background noise propagation is performed for a network of hexagonal buildings. The obtained results suggest that the prediction of background noise in urban spaces is possible by means of a modified diffusion equation using two parameters: the diffusion coefficient that expresses the spreading out of noise resulting from diffuse scattering and multiple reflections by buildings, and an attenuation term accounting for the wall absorption, atmospheric attenuation, and absorption by the open top. The dependence of the diffusion coefficient with geometrical shapes and the diffusive nature of the buildings are investigated in the case of a periodic disposition of hexagonal buildings.

Journal Article↗
PubMed1999

B lymphocyte antigen D8/17 and repetitive behaviors in autism.

OBJECTIVE: Monoclonal antibody D8/17 identifies a B lymphocyte antigen with expanded expression in rheumatic fever, Sydenham's chorea, and subgroups of obsessive-compulsive disorder and Tourette's syndrome with repetitive behaviors. The authors examined the rate of D8/17 expression in children with autism and its correlation with severity of repetitive behaviors. METHOD: Blood samples from 18 patients with autism and 14 comparable medically ill children were evaluated for percentage of D8/17-positive B cells by immunofluorescence and for streptococcal antibodies. Severity of repetitive behaviors was also determined. RESULTS: The frequency of individuals with > or =11% D8/17-positive cells was significantly higher in the autistic patients (78%) than the comparison subjects (21%), severity of repetitive behaviors significantly correlated with D8/17 expression, and D8/17-positive patients had significantly higher compulsion scores than D8/17-negative patients. CONCLUSIONS: D8/17 expression is high in patients with autism and may serve as a marker for compulsion severity within autism.

Adolescent↗
PubMed1999

Imaging in rheumatoid arthritis: results of group discussions.

None of the current scoring methods for radiological damage in rheumatoid arthritis (RA) is ideal. The objective for RA imaging at OMERACT IV was to start discussion about the problems and applicability of the current scoring methods for radiological damage and to start discussion on the challenge of new imaging techniques. The RA imaging module comprised preconference reading material, plenary sessions, small group discussions, and a plenary report of the group sessions, combined with interactive voting. The OMERACT filter guided the discussions. Priorities for further research in imaging studies were: (1) pathologies versus features on radiographs; (2) relation with longterm outcome; and (3) definition of minimum clinically important difference.

Arthritis, Rheumatoid↗