Biomedical subjects

L Soler

Publications and source records attributed to L Soler.

At least 19 recordsLinked to original sources

PubMed2005

A complete augmented reality guidance system for liver punctures: first clinical evaluation.

We provided in an augmented reality guidance system for liver punctures, which has been validated on a static abdominal phantom. In this paper, we report the first in vivo experiments. We developed a strictly passive protocol to directly evaluate our system on patients. We show that the system algorithms work efficiently and we highlight the clinical constraints that we had to overcome (small operative field, weight and sterility of the tracked marker attached to the needle...). Finally, we investigate to what extent breathing motion can be neglected for free breathing patient. Results show that the guiding accuracy, close to 1 cm, is sufficient for large targets only (above 3 cm of diameter) when the breathing motion is neglected. In the near future, we aim at validating our system on smaller targets using a respiratory gating technique.

Allantoin↗

PubMed2005

First record of the rare species Aeromonas culicicola from a drinking water supply.

We describe the recovery of the rare species Aeromonas culicicola, so far known only in mosquitoes in India, from a drinking water supply in Spain. Typing, using enterobacterial repetitive intergenic consensus-PCR, revealed that the 27 new isolates belonged to 3 very closely related strains. These strains were genetically identified by 16S rRNA gene sequencing. Spanish strains differed from the mosquito strains in three nucleotide positions. The AHCYTOEN gene was present in these water strains, which may have a public health significance.

Aeromonas↗

PubMed2005

Trematodes associated with mangrove habitat in Puerto Rican salt marshes.

Batillaria minima is a common snail in the coastal estuaries of Puerto Rico. This snail is host to a variety of trematodes, the most common being Cercaria caribbea XXXI, a microphallid species that uses crabs as second intermediate hosts. The prevalence of infection was higher (7.1%) near mangroves than on mudflats away from mangroves (1.4%). Similarly, there was a significant positive association between the proportion of a site covered with mangroves and the prevalence of the microphallid. The association between mangroves and higher trematode prevalence is most likely because birds use mangroves as perch sites and this results in local transmission to snails.

Animals↗

PubMed2004

Phylogenetic analysis of the genus Aeromonas based on two housekeeping genes.

The phylogenetic relationships of all known species of the genus Aeromonas, and especially Aeromonas bestiarum and Aeromonas salmonicida, were investigated on 70 strains using the rpoD sequence, which encodes the sigma70 factor. This analysis was complemented with the sequence of gyrB, which has already proven useful for determining the phylogenetic relationships in the genus. Nucleotide sequences of rpoD and gyrB showed that both genes had similar substitution rates (< 2 %) and a similar number of variable positions (34 % for rpoD versus 32 % for gyrB). Strain groupings by analysis of rpoD, gyrB and a combination of both genes were consistent with the taxonomic organization of all Aeromonas species described to date. However, the simultaneous analysis of both clocks improved the reliability and the power to differentiate, in particular, closely related taxa. At the inter-species level, gyrB showed a better resolution for differentiating Aeromonas sp. HG11/Aeromonas encheleia and Aeromonas veronii/Aeromonas culicicola/Aeromonas allosaccharophila, while rpoD more clearly differentiated A. salmonicida from A. bestiarum. The analysis of rpoD provided initial evidence for clear phylogenetic divergence between the latter two species.

Aeromonas↗

PubMed2004

Type III secretion system genes in clinical Aeromonas isolates.

We have identified the genes ascF and ascG, which encode components of a putative type III secretion system (TTSS) in AEROMONAS: We investigated the distribution of these and other TTSS genes in 84 clinical isolates and found hybridizing sequences in 50% of the strains, with a higher prevalence in Aeromonas hydrophila and Aeromonas veronii than in Aeromonas caviae.

Aeromonas↗

PubMed2003

Characterisation of Aeromonas spp. isolated from frozen fish intended for human consumption in Mexico.

A total of 82 strains of presumptive Aeromonas spp. were identified biochemically and genetically (16S rDNA-RFLP). The strains were isolated from 250 samples of frozen fish (Tilapia, Oreochromis niloticus niloticus) purchased in local markets in Mexico City. In the present study, we detected the presence of several genes encoding for putative virulence factors and phenotypic activities that may play an important role in bacterial infection. In addition, we studied the antimicrobial patterns of those strains. Molecular identification demonstrated that the prevalent species in frozen fish were Aeromonas salmonicida (67.5%) and Aeromonas bestiarum (20.9%), accounting for 88.3% of the isolates, while the other strains belonged to the species Aeromonas veronii (5.2%), Aeromonas encheleia (3.9%) and Aeromonas hydrophila (2.6%). Detection by polymerase chain reaction (PCR) of genes encoding putative virulence factors common in Aeromonas, such as aerolysin/hemolysin, lipases including the glycerophospholipid-cholesterol acyltransferase (GCAT), serine protease and DNases, revealed that they were all common in these strains. Our results showed that first generation quinolones and second and third generation cephalosporins were the drugs with the best antimicrobial effect against Aeromonas spp. In Mexico, there have been few studies on Aeromonas and its putative virulence factors. The present work therefore highlights an important incidence of Aeromonas spp., with virulence potential and antimicrobial resistance, isolated from frozen fish intended for human consumption in Mexico City.

Aeromonas↗

PubMed2003

Distribution of virulence genes in clinical and environmental isolates of Aeromonas spp.

The distribution and phenotypic activity of the genes encoding for serine protease, glycerophospholipid-cholesterol acyltransferase, lipases, aerolysin/hemolysin and DNases were investigated in 234 isolates identified by 16S rDNA-RFLP representing all the species of Aeromonas. The former three genes were found to be highly conserved among the genus. Aerolysin/hemolysin and DNase genes and beta-hemolytic activity were significantly more frequent in clinical than in environmental isolates. Aerolysin/hemolysin and serine protease genes were present in all beta-hemolytic strains supporting serine protease as possibly important for the activation of the former gene. The high prevalence of virulence factors in clinical isolates indicates that they may play a role in the mechanisms of pathogenesis of these microorganisms.

Acyltransferases↗

PubMed2003

Evaluation of two miniaturized systems, MicroScan W/A and BBL Crystal E/NF, for identification of clinical isolates of Aeromonas spp.

Fifty-two clinical strains and 22 type and reference Aeromonas strains, previously genetically characterized by 16S rRNA gene restriction fragment length polymorphism, were identified in parallel with the MicroScan Walk/Away and BBL Crystal Enteric/Nonfermenter systems. The former identified only 14.8% of the isolates correctly, and the latter identified only 20.3% correctly, which indicates that neither of these systems is useful for this purpose.

Aeromonas↗

PubMed2002

[Image fusion, virtual reality, robotics and navigation. Effects on surgical practice].

In the new minimally invasive surgical era, virtual reality, robotics, and image merging have become topics on their own, offering the potential to revolutionize current surgical treatment and assessment. Improved patient care in the digital age seems to be the primary impetus for continued efforts in the field of telesurgery. The progress in endoscopic surgery with regard to telesurgery is manifested by digitization of the pre-, intra-, and postoperative interaction with the patients' surgical disease via computer system integration: so-called Computer Assisted Surgery (CAS). The preoperative assessment can be improved by 3D organ reconstruction, as in virtual colonoscopy or cholangiography, and by planning and practicing surgery using virtual or simulated organs. When integrating all of the data recorded during this preoperative stage, an enhanced reality can be made possible to improve intra-operative patient interactions. CAS allows for increased three-dimensional accuracy, improved precision and the reproducibility of procedures. The ability to store the actions of the surgeon as digitized information also allows for universal, rapid distribution: i.e., the surgeon's activity can be transmitted to the other side of the operating room or to a remote site via high-speed communications links, as was recently demonstrated by our own team during the Lindbergh operation. Furthermore, the surgeon will be able to share his expertise and skill through teleconsultation and telemanipulation, bringing the patient closer to the expert surgical team through electronic means and opening the way to advanced and continuous surgical learning. Finally, for postoperative interaction, virtual reality and simulation can provide us with 4 dimensional images, time being the fourth dimension. This should allow physicians to have a better idea of the disease process in evolution, and treatment modifications based on this view can be anticipated. We are presently determining the accuracy and efficacy of 4 dimensional imaging compared to conventional evaluations.

Computer Systems↗

PubMed2002

A DNA probe specific for Aeromonas colonies.

Members of the genus Aeromonas are important enteropathogens. Commercial identification systems are often unable to correctly identify Aeromonas strains and misidentification as Vibrio spp. is common. A digoxigenin-DNA probe based on a 237 bp of the glycerophospholipid-cholesterol acyltransferase gene has been tested in a colony hybridization assay. The probe hybridized with all Aeromonas species tested (n = 16) but not with strains of other enteropathogenic bacteria (n = 20). The probe allowed the unequivocal identification of Aeromonas in primary isolation media within 36 h.

Acyltransferases↗

PubMed2002

Phenotypic characteristics and pathogenicity of Aeromonas genomospecies isolated from common carp (Cyprinus carpio L.).

AIMS: To evaluate the relationship between the genomospecies, phenotypic profile and pathogenicity for carp of 37 motile Aeromonas strains. METHODS AND RESULTS: Aeromonas strains were identified to genomospecies level by the 16S rDNA restriction fragment length polymorphism (RFLP) method and characterized phenotypically by the API 20E and API Zym systems and by conventional tube or plate methods. 16S rDNA RFLP analysis showed that the strains belonged to five species, Aeromonas bestiarum (5), Aerom. salmonicida (13), Aerom. veronii (11), Aerom. sobria (6) and Aerom. encheleia (2). Most strains of Aerom. bestiarum (80%) and Aerom. salmonicida (85%) could be separated by growth at 4 and 42 degrees C, autoagglutination after boiling, reaction for lipase (C14) and naphthol-AS-BI-phosphohydrolase. All strains of Aerom. veronii corresponded to Aerom. veronii biotype sobria and could be separated from Aerom. sobria by citrate utilization, growth at 37 and 42 degrees C, amygdalin and cellobiose fermentation. All strains of Aerom. bestiarum and most strains of Aerom. salmonicida (76.9%) and Aerom. veronii (63.6%) were pathogenic for carp. CONCLUSIONS: The biochemical identification of carp Aeromonas strains is not entirely clear. Some association between Aeromonas species, phenotypic profile and specific disease signs was observed. SIGNIFICANCE AND IMPACT OF THE STUDY: The results will be useful for ichthyopathology laboratories in the diagnosis of motile aeromonad septicaemia in carp.

Aeromonas↗

PubMed2001

Fully automatic anatomical, pathological, and functional segmentation from CT scans for hepatic surgery.

OBJECTIVE: To improve the planning of hepatic surgery, we have developed a fully automatic anatomical, pathological, and functional segmentation of the liver derived from a spiral CT scan. MATERIALS AND METHODS: From a 2 mm-thick enhanced spiral CT scan, the first stage automatically delineates skin, bones, lungs, kidneys, and spleen by combining the use of thresholding, mathematical morphology, and distance maps. Next, a reference 3D model is immersed in the image and automatically deformed to the liver contours. Then an automatic Gaussian fitting on the imaging histogram estimates the intensities of parenchyma, vessels, and lesions. This first result is next improved through an original topological and geometrical analysis, providing an automatic delineation of lesions and veins. Finally, a topological and geometrical analysis based on medical knowledge provides hepatic functional information that is invisible in medical imaging: portal vein labeling and hepatic anatomical segmentation according to the Couinaud classification. RESULTS: Clinical validation performed on more than 30 patients shows that delineation of anatomical structures by this method is often more sensitive and more specific than manual delineation by a radiologist. CONCLUSION: This study describes the methodology used to create the automatic segmentation of the liver with delineation of important anatomical, pathological, and functional structures from a routine CT scan. Using the methods proposed in this study, we have confirmed the accuracy and utility of the creation of a 3D liver model compared with the conventional reading of the CT scan by a radiologist. This work may allow improved preoperative planning of hepatic surgery by more precisely delineating liver pathology and its relationship to normal hepatic structures. In the future, this data may be integrated with computer-assisted surgery and thus represents a first step towards the development of an augmented-reality surgical system.

Humans↗

PubMed2001

Teleeducation in surgery: European Institute for Telesurgery experience.

The information age is revolutionizing the practice and education of surgery. The use of video-conference systems through Integrated Service Digital Network (ISDN) teletransmission connects surgeons around the world without the limits of distance. Teleeducation, teleteaching, teletraining, telementoring, and teleaccreditation have been clearly demonstrated and are now common practice. Pre- and perioperative surgical advice may be obtained from expert networks. Patient data can be reconstructed as virtual tridimensional images analyzed by computers, and the surgical procedure can be simulated to obtain an optimal surgical decision. Finally, the use of the Internet will provide access to this information, whenever and wherever necessary, through dedicated websites. It remains to be adequately demonstrated that these means will allow improvement in patient care.

Computer Simulation↗

PubMed2001

Associations of high myopia in childhood.

PURPOSE: High myopia in early childhood is a recognised association of ocular and systemic disease. The aim of this study was to describe the types, pattern and frequency of these associations. METHODS: All children presenting to two ophthalmology units over 3 years who were found to have high myopia were recruited. High myopia was defined as one or both eyes demonstrating 6 dioptres spherical equivalent or more of myopic refractive error on retinoscopy. We limited the age to less than 10 years old. A retrospective case review was undertaken of the 112 consecutive children who fulfilled the criteria above. The demographic data, source and indication for referral were recorded along with the ocular and systemic findings and diagnosis. RESULTS: Only 9 (8%) of the children had 'simple high myopia' with no associated ocular or systemic associations. In 54% there was an underlying systemic association with or without further ocular problems (e.g. developmental delay, prematurity, Marfan, Stickler, Noonan, Down syndrome) and in the remaining 38% there were further ocular problems associated with the high myopia (e.g. lens subluxation, coloboma, retinal dystrophy, anisometropic amblyopia). A family history of high myopia did not preclude associated abnormality: in 4 cases the diagnosis of a systemic condition in the child led to the identification of the disease in at least one myopic relative. Asian (p < 0.001) and male (p < 0.05) patients were overrepresented in the series. CONCLUSION: High myopia is strongly associated with systemic and ocular problems; it may be the reason for the child's initial medical referral and an important clue to an underlying systemic or ocular condition. Referrals infrequently originated from community optometrists despite prior attendance. We suggest that all children under 10 years of age with high myopia are referred to a paediatric ophthalmology clinic for review and we propose a structured clinical evaluation in the hospital eye clinic.

Child↗

PubMed2001

Safety in computer assisted surgery.

Today, surgeons accept computer assisted technologies as important tools to enhance the treatment of a patient. The positive impact and acceptance of computer assisted technologies could be increased to a great extent, if all methods and devices used for diagnosis and treatment of a patient are better co-ordinated and more finely tuned. Often computer assisted treatments cannot be performed due to a lack of communication between hospital departments, useless patient data, deficient interfaces, etc. Risks for the patient and potential errors within the treatment are often unrecognised, as up to now the safety of computer integrated surgery is only product-, device and security oriented. We have developed a new approach for a safety architecture, which includes safety aspects considering patients, users, interdependencies and interactions of computer assisted methods and apparatuses.

Computer Systems↗

PubMed2000

Extended method for discrimination of Aeromonas spp. by 16S rDNA RFLP analysis.

A previously described molecular method, based on 16S rDNA RFLP analysis, for the identification of Aeromonas spp. was unable to separate the species Aeromonas salmonicida, Aeromonas bestiarum and the recently described Aeromonas popoffii. In this study, the method has been extended with endonucleases AIwNI and PstI for the identification of these species. A molecular frame for the identification of all known Aeromonas spp. is presented.

Aeromonas↗

PubMed2000

Virtual university applied to telesurgery: from teleeducation to telemanipulation.

UNLABELLED: PROBLEM/BACKGROUND: In order to improve patient care by minimal invasive surgery (MIS), we perfected a Virtual TeleSurgical University that allows for teleeducation, teleconcertation, surgical planning and telemanipulation, through new Virtual Reality and multimedia systems. TOOLS AND METHODS: The organization of this innovative school was federated around three major research programs. First, the TESUS program focused on the teletransmission of medical information, allowing for videoconferencing around the world and telementoring. Next, the WeBS-Surg program is a multimedia continuous surgical education system on internet, that allows for teleeducation and teleconcertation between world experts in MIS. Then, the MASTER program (Minimal Access Surgery by Telecommunications and Robotics) allowed the development of the third millenium Operating room. It included Virtual Reality systems that delineate automatically anatomical and pathological structures of a patients from him CT-scan, and that allow for an interactive surgical planning and force-feed-back simulation. It also included a telesurgical robot named Zeus controlled by surgeons through telemanipulation system. RESULTS: Tests and validation shows that all these systems improved all steps of the surgical procedure: preoperatively due to a better continuous education and a computer assisted surgical planning, and peroperatively due to teleconcertation, telementoring and telemanipulation systems. CONCLUSION: Revolutionary tools for minimal invasive surgery learning, planning and performing are all ready available. These tools represents the first prototype of the computer assisted tele-robotical surgery that will be the future of surgery.

Computer Simulation↗

PubMed2000

An automatic virtual patient reconstruction from CT-scans for hepatic surgical planning.

UNLABELLED: PROBLEM/BACKGROUND: In order to help hepatic surgical planning we perfected automatic 3D reconstruction of patients from conventional CT-scan, and interactive visualization and virtual resection tools. TOOLS AND METHODS: From a conventional abdominal CT-scan, we have developed several methods allowing the automatic 3D reconstruction of skin, bones, kidneys, lung, liver, hepatic lesions, and vessels. These methods are based on deformable modeling or thresholding algorithms followed by the application of mathematical morphological operators. From these anatomical and pathological models, we have developed a new framework for translating anatomical knowledge into geometrical and topological constraints. More precisely, our approach allows to automatically delineate the hepatic and portal veins but also to label the portal vein and finally to build an anatomical segmentation of the liver based on Couinaud definition which is currently used by surgeons all over the world. Finally, we have developed a user friendly interface for the 3D visualization of anatomical and pathological structures, the accurate evaluation of volumes and distances and for the virtual hepatic resection along a user-defined cutting plane. RESULTS: A validation study on a 30 patients database gives 2 mm of precision for liver delineation and less than 1 mm for all other anatomical and pathological structures delineation. An in vivo validation performed during surgery also showed that anatomical segmentation is more precise than the delineation performed by a surgeon based on external landmarks. This surgery planning system has been routinely used by our medical partner, and this has resulted in an improvement of the planning and performance of hepatic surgery procedures. CONCLUSION: We have developed new tools for hepatic surgical planning allowing a better surgery through an automatic delineation and visualization of anatomical and pathological structures. These tools represent a first step towards the development of an augmented reality system combined with computer assisted tele-robotical surgery.

Computer Graphics↗