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1.
Brain Spine ; 4: 102822, 2024.
Article in English | MEDLINE | ID: mdl-38831935

ABSTRACT

Introduction: Technical advances and the increasing role of interdisciplinary decision-making may warrant formal definitions of expertise in surgical neuro-oncology. Research question: The EANS Neuro-oncology Section felt that a survey detailing the European neurosurgical perspective on the concept of expertise in surgical neuro-oncology might be helpful. Material and methods: The EANS Neuro-oncology Section panel developed an online survey asking questions regarding criteria for expertise in neuro-oncological surgery and sent it to all individual EANS members. Results: Our questionnaire was completed by 251 respondents (consultants: 80.1%) from 42 countries. 67.7% would accept a lifetime caseload of >200 cases and 86.7% an annual caseload of >50 as evidence of neuro-oncological surgical expertise. A majority felt that surgeons who do not treat children (56.2%), do not have experience with spinal fusion (78.1%) or peripheral nerve tumors (71.7%) may still be considered experts. Majorities believed that expertise requires the use of skull-base approaches (85.8%), intraoperative monitoring (83.4%), awake craniotomies (77.3%), and neuro-endoscopy (75.5%) as well as continuing education of at least 1/year (100.0%), a research background (80.0%) and teaching activities (78.7%), and formal interdisciplinary collaborations (e.g., tumor board: 93.0%). Academic vs. non-academic affiliation, career position, years of neurosurgical experience, country of practice, and primary clinical interest had a minor influence on the respondents' opinions. Discussion and conclusion: Opinions among neurosurgeons regarding the characteristics and features of expertise in neuro-oncology vary surprisingly little. Large majorities favoring certain thresholds and qualitative criteria suggest a consensus definition might be possible.

2.
Acta Neurochir Suppl ; 135: 339-343, 2023.
Article in English | MEDLINE | ID: mdl-38153490

ABSTRACT

BACKGROUND: The cervical lateral approach can enlarge the spinal canal and foramen to achieve an effective neural decompression without needing spine stabilization. For this review, the authors' main objective was to illustrate the rationale, advantages, disadvantages, complications, and pitfalls of this technique, highlighting also areas for future development. MATERIALS AND METHODS: A Medline via PubMed database search was carried out by using both keywords, namely "cervical oblique corpectomy," "multilevel oblique corpectomy and foraminotomy," and "lateral vertebrectomy," and Medical Subject Headings (MeSH) terms from 1 January 1991, up to 31 December 2021. RESULTS: The analyzed articles suggested that the use of such a technique has declined over time; only 29 clinical studies met all the inclusion criteria and were retained for data analysis, including 1200 patients undergoing such an approach for the management of degenerative cervical myelopathies (DCMs) or of radiculopathies. The main etiopathogeneses were cervical stenosis, degenerative disk disease, or a mix of them-78% of which had a favorable outcome; the most frequent complications were transient and permanent Horner syndrome in 13.6% and 9.2% of cases, respectively. Long-term stability was reported in 97% of patients. CONCLUSION: Multilevel cervical oblique vertebrectomy and/or lateral foraminotomy allow wide neural structure decompression and optimal stability given that the physiological spinal motion is preserved.


Subject(s)
Radiculopathy , Spinal Cord Diseases , Humans , Radiculopathy/etiology , Radiculopathy/surgery , Cervical Vertebrae/surgery , Neck , Spinal Cord Diseases/diagnostic imaging , Spinal Cord Diseases/surgery , Databases, Factual
3.
Brain Spine ; 3: 102669, 2023.
Article in English | MEDLINE | ID: mdl-37720459

ABSTRACT

Introduction: Orbital surgery has always been disputed among specialists, mainly neurosurgeons, otorhinolaryngologists, maxillofacial surgeons and ophthalmologists. The orbit is a borderland between intra- and extracranial compartments; Krönlein's lateral orbitotomy and the orbitozygomatic infratemporal approach are the historical milestones of modern orbital-cranial surgery. Research question: Since its first implementation, endoscopy has significantly impacted neurosurgery, changing perspectives and approaches to the skull base. Since its first application in 2009, transorbital endoscopic surgery opened the way for new surgical scenario, previously feasible only with extensive tissue dissection. Material and methods: A PRISMA based literature search was performed to select the most relevant papers on the topic. Results: Here, we provide a narrative review on the current state and future trends in endoscopic orbital surgery. Discussion and conclusion: This manuscript is a joint effort of the EANS frontiers committee in orbital tumors and the EANS skull base section.

4.
Rev Epidemiol Sante Publique ; 71(3): 101595, 2023 Jun.
Article in French | MEDLINE | ID: mdl-37068363

ABSTRACT

INTRODUCTION: Neurodevelopmental disorders (NDD) affect 5 to 15% of the population. Improved management largely depends on early detection in primary care. A screening tool was developed by an expert consensus and its use has been recommended since 2019. This tool has never been evaluated to date. The aim of this study was to investigate the prevalence and factors associated with the identification of neurodevelopmental disorders in primary care in children aged 6 months to 5 years. METHOD: This work is a multicentric observational study carried out in general practice in two regions of France: Île-de-France and Auvergne-Rhône-Alpes. A multivariate analysis was performed to identify the factors associated with the presence of abnormal signs on the grid. RESULTS: Five hundred and sixty-four (564) children aged 6 months to 4 years were included. The prevalence of children identified on the grid was 3.9%. The factors associated with the neurodevelopmental disorders identified in multivariate analysis were: low socio-professional status of the mother, male gender and parental concern about the child's neurodevelopment. Factors associated with identifying a developmental trajectory gap were male gender (OR = 2.10 (1.22-3.62)) and low socio-professional status of the mother (OR = 2.23 [1.05-4.70]). CONCLUSION: This original work allowed us to carry out first-line testing of a tool for the identification of NDD in primary care and to evaluate the prevalence of identification of these disorders. A complementary cohort study will be necessary to evaluate the sensitivity and specificity of this identification tool.


Subject(s)
Neurodevelopmental Disorders , Child , Female , Humans , Male , Cohort Studies , Neurodevelopmental Disorders/diagnosis , Neurodevelopmental Disorders/epidemiology , Mothers , Parents , Primary Health Care
5.
Acta Neurochir (Wien) ; 163(12): 3387-3400, 2021 12.
Article in English | MEDLINE | ID: mdl-34398339

ABSTRACT

BACKGROUND: The optimal management of clinoidal meningiomas (CMs) continues to be debated. METHODS: We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of these tumors. The data from the literature along with contemporary practice patterns were discussed within the task force to generate consensual recommendations. RESULTS AND CONCLUSION: This article represents the consensus opinion of the task force regarding pre-operative evaluations, patient's counselling, surgical classification, and optimal surgical strategy. Although this analysis yielded only Class B evidence and expert opinions, it should guide practitioners in the management of patients with clinoidal meningiomas and might form the basis for future clinical trials.


Subject(s)
Meningeal Neoplasms , Meningioma , Consensus , Humans , Meningeal Neoplasms/surgery , Meningioma/surgery , Neurosurgical Procedures , Retrospective Studies , Skull Base
6.
Acta Neurochir (Wien) ; 163(6): 1639-1663, 2021 06.
Article in English | MEDLINE | ID: mdl-33740134

ABSTRACT

BACKGROUND: The optimal management of petroclival meningiomas (PCMs) continues to be debated along with several controversies that persist. METHODS: A task force was created by the EANS skull base section along with its members and other renowned experts in the field to generate recommendations for the management of these tumors. To achieve this, the task force reviewed in detail the literature in this field and had formal discussions within the group. RESULTS: The constituted task force dealt with the existing definitions and classifications, pre-operative radiological investigations, management of small and asymptomatic PCMs, radiosurgery, optimal surgical strategies, multimodal treatment, decision-making, and patient's counselling. CONCLUSION: This article represents the consensually derived opinion of the task force with respect to the management of PCMs.


Subject(s)
Meningeal Neoplasms/surgery , Meningioma/surgery , Skull Base/surgery , Clinical Decision-Making , Counseling , Humans , Radiosurgery
7.
J Chem Phys ; 152(2): 024503, 2020 Jan 14.
Article in English | MEDLINE | ID: mdl-31941324

ABSTRACT

Using molecular dynamics simulations, we compare the motion of a nanoswimmer based on Purcell's suggested motor with a time asymmetrical cycle with the motion of the same molecular motor with a time symmetrical cycle. We show that Purcell's theorem still holds at the nanoscale, despite the local structure and the medium's fluctuations. Then, with the purpose of both orienting the swimmer's displacement and increasing the breakdown of the theorem, we study the effect of an electric field on a polarized version of these swimmers. For small and large fields, the time asymmetrical swimmer is more efficient, as suggested by Purcell. However, we find a field range for which Purcell's theorem is broken for the time symmetric motor. Results suggest that the breakdown of the theorem arises from the competition of the orientation field and Brownian forces, while for larger fields, the field destroys the effect of fluctuations restoring the theorem.

8.
Trials ; 20(1): 282, 2019 May 22.
Article in English | MEDLINE | ID: mdl-31118095

ABSTRACT

BACKGROUND: Leisure activities can be both enjoyable and cognitively stimulating, and participation in such activities has been associated with reduced age-related cognitive decline. Thus, integrating stimulating leisure activities in cognitive training programs may represent a powerful and innovative approach to promote cognition in older adults at risk of dementia. The ENGAGE study is a randomized controlled, double-blind preference trial with a comprehensive cohort design that will test the efficacy and long-term impact of an intervention that combines cognitive training and cognitively stimulating leisure activities. METHODS: One hundred and forty-four older adults with a memory complaint will be recruited in Montreal and Toronto. A particular effort will be made to reach persons with low cognitive reserve. Participants will be randomly assigned to one of two conditions: cognitive + leisure training (ENGAGE-MUSIC/SPANISH) or active control (ENGAGE-DISCOVERY). The ENGAGE-MUSIC/SPANISH training will include teaching of mnemonic and attentional control strategies, casual videogames selected to train attention, and classes in music or Spanish as a second language. The ENGAGE-DISCOVERY condition will comprise psychoeducation on cognition and the brain, low-stimulating casual videogames and documentary viewing with discussions. To retain the leisure aspect of the activities, participants will be allowed to exclude either music or Spanish at study entry if they strongly dislike one of these activities. Participants randomized to ENGAGE-MUSIC/SPANISH who did not exclude any activity will be assigned to music or Spanish based on a second random assignment. Training will be provided in 24 2-h sessions over 4 months. Outcomes will be measured at baseline, at 4-month follow-up, and at 24-month follow-up. The primary outcome will be cognitive performance on a composite measure of episodic memory (delayed recall scores for words and face-name associations) measured at baseline and at the 4-month follow-up. Secondary outcomes will include a composite measure of attention (speed of processing, inhibition, dual tasking, and shifting), psychological health, activities of daily living, and brain structure and function and long-term maintenance measured at the 24-month follow-up. Information on cognitive reserve proxies (education and lifestyle questionnaires), sex and genotype (apolipoprotein (Apo)E4, brain-derived neurotrophic factor (BDNF), and catechol-O-methyltransferase (COMT)) will be collected and considered as moderators of training efficacy. DISCUSSION: This study will test whether a program combining cognitive training with stimulating leisure activities can increase cognition and reduce cognitive decline in persons at risk of dementia. TRIAL REGISTRATION: NCT03271190 . Registered on 5 September 2017.


Subject(s)
Cognition , Leisure Activities , Memory Disorders/therapy , Randomized Controlled Trials as Topic , Activities of Daily Living , Aged , Aged, 80 and over , Attention , Brain/pathology , Brain/physiopathology , Cohort Studies , Double-Blind Method , Humans , Memory Disorders/psychology , Middle Aged , Outcome Assessment, Health Care , Research Design
9.
J Dent Res ; 97(12): 1306-1316, 2018 11.
Article in English | MEDLINE | ID: mdl-29879364

ABSTRACT

The most common outcome of defective dental morphogenesis in human patients is dental agenesis (absence of teeth). This may affect either the primary or permanent dentition and can range from 5 or fewer missing teeth (hypodontia), 6 or more (oligodontia), to complete absence of teeth (anodontia). Both isolated and syndromic dental agenesis have been reported to be associated with a large number of mutated genes. The aim of this review was to analyze the dental phenotypes of syndromic and nonsyndromic dental agenesis linked to gene mutations. A systematic review of the literature focusing on genes ( MSX1, PAX9, AXIN2, PITX2, WNT10A, NEMO, EDA, EDAR, EDARADD, GREMLIN2, LTBP3, LRP6, and SMOC2) known to be involved in dental agenesis was performed and included 101 articles. A meta-analysis was performed using the dental phenotypes of 522 patients. The total number and type of missing teeth were analyzed for each mutated gene. The percentages of missing teeth for each gene were compared to determine correlations between genotypes and phenotypes. Third molar agenesis was included in the clinical phenotype assessment. The findings show that isolated dental agenesis exists as part of a spectrum of syndromes for all the identified genes except PAX9 and that the pattern of dental agenesis can be useful in clinical diagnosis to identify (or narrow) the causative gene mutations. While third molar agenesis was the most frequent type of dental agenesis, affecting 70% of patients, it was described in only 30% of patients with EDA gene mutations. This study shows that the pattern of dental agenesis gives information about the mutated gene and could guide molecular diagnosis for geneticists.


Subject(s)
Anodontia/genetics , Mutation/genetics , Genotype , Humans , Phenotype , Syndrome
10.
Neurochirurgie ; 63(6): 458-467, 2017 Dec.
Article in French | MEDLINE | ID: mdl-29122304

ABSTRACT

INTRODUCTION: Vertebral hemangiomas (VH) represent the most common primary bone tumor of the spine and are rarely symptomatic. Currently, there is no consensus for treatment and many therapeutic options are available, alone or in combination including cementoplasty, sclerotherapy, surgery, embolization and/or radiotherapy. OBJECTIVE: To evaluate the clinical and radiological outcome of a multimodal management for symptomatic VH. METHODS: A consecutive prospective and retrospective multicenter study was conducted to review cases of symptomatic VHs between 2005 and 2015. Clinical and radiological aspects, treatment modalities and complications were evaluated preoperatively; postoperatively and at last follow-up. We also reviewed the literature of studies concerning case series of VH, published after 1990 and involving more than 10 patients. RESULTS: Twenty-seven VHs were included in our series (mean age at diagnosis: 47.9 years), out of which 26 were symptomatic. Ten presented with neurologic deficit (37%). An epidural extension was noted in 13 patients (48%). Eleven patients (41%) underwent multimodal treatments. In the multimodal group, eradication was observed in 6 patients (54%), stable residue in 5 cases (46%) with no recurrence versus 3 eradication (23%), 9 stable residue (69%) and no recurrence in the monomodal group, (P>0.05). The literature comprised 14 studies including 458 patients. Only 4 studies were focused on multimodal treatments. CONCLUSION: Based on this study, the multimodal management of symptomatic VHs appeared safe and effective. Finally, we propose an algorithm for symptomatic VHS management based on the severity of epidural extension and fracture risk.


Subject(s)
Hemangioma/therapy , Spinal Neoplasms/therapy , Algorithms , Combined Modality Therapy , Humans , Middle Aged , Prospective Studies , Retrospective Studies
12.
Mar Pollut Bull ; 108(1-2): 275-80, 2016 Jul 15.
Article in English | MEDLINE | ID: mdl-27184131

ABSTRACT

Identifying environmental damage due to anthropogenic activities is a focal point for scientists and policy makers like those involved in the European Water Framework Directive (WFD). Many of these approaches focus on ecological endpoints for assessing environmental perturbations, which lead to policies emphasizing mitigation rather than prevention. Biomarkers provide early-warning indicators of stress but it is necessary to distinguish their natural variations from those induced by chemical stress. The global aim of this study was to establish a baseline assessment criterion (BAC) using historical data in a reference site to define toxicity thresholds. We have developed a multiple polynomial regression model (MPR) accounting the influence of salinity, temperature and size of individual on energetic reserves (glycogen and lipids) in the marine polychaete Hediste diversicolor. The model identified a complex, orthogonal relationship between confounding factors and glycogen and a linear relationship between lipids and size of individuals.


Subject(s)
Environmental Monitoring/methods , Glycogen/metabolism , Lipid Metabolism/drug effects , Polychaeta/drug effects , Polychaeta/metabolism , Water Pollutants, Chemical/toxicity , Animals , Biomarkers/metabolism , Regression Analysis , Salinity
13.
Article in English | MEDLINE | ID: mdl-25353596

ABSTRACT

Starting from fundamental hydrodynamics and thermodynamics equations for thermoviscous fluids, a new modeling procedure, which is suitable to describe acoustic propagation in gas mixtures, is presented. The model revises the boundary conditions which are appropriate to describe the condensation-evaporation processes taking place on a solid wall when one component of the mixture approaches saturation conditions. The general analytical solutions of these basic equations now give a unified description of acoustic propagation in an infinite, semi-infinite, or finite medium, throughout and beyond the boundary layers. The solutions account for the coupling between acoustic propagation and heat and concentration diffusion processes, including precondensation on the walls. The validity of the model and its predictive capability have been tested by a comparison with the description available in the literature of two particular systems (precondensation of propane and acoustic attenuation in a duct filled with an air-water vapor saturated mixture). The results of this comparison are discussed to clarify the relevance of the various physical phenomena that are involved in these processes. The model proposed here might be useful to develop methods for the acoustic determination of the thermodynamic and transport properties of gas mixtures as well as for practical applications involving gas and gas-vapor mixtures like thermoacoustics and acoustics in wet granular or porous media.

15.
J Neuroradiol ; 39(2): 119-22, 2012 May.
Article in English | MEDLINE | ID: mdl-21641646

ABSTRACT

Primary solitary amyloidoma of Meckel's cave is rare, and a bilateral location is even more rare. To the best of our knowledge, only 12 cases in the literature have described such a primary lesion, including one case of bilateral involvement of Meckel's cave. We report here on the case of a 57-year-old woman presenting with pseudotumor masses involving both Meckel's caves and responsible for trigeminal neuropathy. The final diagnosis of amyloidoma was made on the basis of histological examination of surgical biopsy specimens.


Subject(s)
Amyloidosis/diagnosis , Cranial Nerve Neoplasms/diagnosis , Dura Mater/pathology , Amyloidosis/complications , Amyloidosis/surgery , Biopsy , Cranial Nerve Neoplasms/complications , Cranial Nerve Neoplasms/surgery , Diagnosis, Differential , Female , Humans , Magnetic Resonance Angiography , Magnetic Resonance Imaging , Magnetic Resonance Imaging, Interventional , Middle Aged , Positron-Emission Tomography , Tomography, X-Ray Computed , Trigeminal Nerve Diseases/etiology , Trigeminal Nerve Diseases/surgery
16.
J Neuroradiol ; 37(2): 83-8, 2010 May.
Article in English | MEDLINE | ID: mdl-20381147

ABSTRACT

INTRODUCTION: The Solitaire stent is the first fully retractable stent for endovascular treatment (EVT) of intracranial aneurysms. The aim of this study was to evaluate its use in a prospective series with mid-term follow-up. METHODS: A retrospective review of our prospectively maintained database identified all patients treated with a Solitaire stent. Clinical charts, procedural data, angiographic results were reviewed. RESULTS: Between June 2008 and September 2009, 15 patients with 17 wide-necked or fusiform aneurysms (16 unruptured/one ruptured) were identified. EVT was successfully performed in all but one patient in whom the stent was removed because it induced flow reduction in the 1.8-mm parent artery. Among 14 treated patients, 13 had an excellent outcome and one had a good outcome. In this latter patient, the first stent could not be delivered and was changed for another one that was successfully deployed. The patient experienced a thrombo-embolic complication 6 hours after EVT and kept a slight hand paresis. In all cases but one, the stent was thus easily navigated and positioned despite a relative poor visibility. Angiographic results included eight complete occlusions, two neck remnants, and six incomplete occlusions. Six-month control in 14 aneurysms showed 13 complete occlusions and one incomplete occlusion. CONCLUSION: The Solitaire stent is useful for EVT of complex intracranial aneurysms because it is fully retractable, easy to navigate and to precisely place. However, it should be used with caution in arteries less than 2mm in diameter.


Subject(s)
Intracranial Aneurysm/therapy , Stents , Adult , Cerebral Angiography , Databases, Factual , Female , Follow-Up Studies , Humans , Intracranial Aneurysm/pathology , Male , Middle Aged , Retrospective Studies , Stents/adverse effects , Treatment Outcome
17.
J Neuroradiol ; 36(4): 228-32, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19766311

ABSTRACT

INTRODUCTION: Endovascular treatment (EVT) of anterior choroidal artery aneurysms (AChAA) may be challenging because of the close relationship with the parent artery. The aim of this study was to report our experience with EVT of AChAA. METHODS: A retrospective review of our prospectively maintained database identified all AChAA treated by embolization. The clinical charts, procedural data and angiographic results were reviewed. RESULTS: From April 2004-August 2008, 11 patients were identified. Five patients presented with a subarachnoid hemorrhage (SAH) and six patients were asymptomatic. Aneurysms size varied from two to 13 mm (mean size=3.6 mm) and nine had an unfavourable neck/sac ratio (>or=0.7). The anterior choroidal artery was arising from the sac (n=6) or from the neck (n=5). Endovascular treatment consisted of balloon-assisted coiling (n=8), coiling (n=2) and stent-assisted coiling (n=1). No procedural complication occurred and all patients had an excellent outcome except one patient who died because of severe vasospasm 8 days after an uneventful EVT. Immediate angiographic control showed six complete occlusions, one neck remnant and four incomplete occlusions. Follow-up controls (mean=18 months) were obtained in eight patients and showed five stable occlusions and three further thrombosis achieving complete occlusion. CONCLUSION: EVT of AChAA is associated with very good clinical and long-term anatomical results. Because of their small size, unfavourable neck/sac ratio and close relationship with the parent artery, EVT frequently requires the use of adjunctive techniques such as balloon or stent-assisted coiling.


Subject(s)
Choroid Plexus/blood supply , Embolization, Therapeutic/methods , Intracranial Aneurysm/therapy , Adult , Cerebral Angiography , Female , Humans , Male , Middle Aged , Radiography, Interventional , Retrospective Studies , Treatment Outcome
18.
J Neuroradiol ; 34(4): 250-9, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17765306

ABSTRACT

BACKGROUND AND PURPOSE: To prospectively evaluate the results of endovascular treatment (EVT) of intracranial aneurysms when it is considered as first-intention treatment. METHODS: From April 2004-October 2006, 167 consecutive patients with 202 aneurysms were treated in our institution. Five patients with a ruptured aneurysm with an associated haematoma were excluded. In 162 patients with 197 aneurysms, EVT was considered as first-intention treatment. RESULTS: Surgical clipping was performed in 25 aneurysms (25/197=12.7%) including 22 aneurysms excluded from EVT and three EVT failures. EVT was thus attempted in 144 patients with 175 aneurysms and successfully performed in 141 patients with 172 aneurysms (172/197=87.3%). EVT failure rate was 1.7%. Clinical outcome according to the modified Glasgow Outcome Scale was: Excellent, 81.5%; Good, 7%; Poor or Fair, 3.5%; Death, 8%. Procedural complications occurred in 17 cases (10%). Balloon- or stent-assisted techniques were used in 60 cases (34.9%) and were not associated with higher complication rate. Overall procedural morbidity and mortality rates were 4.2 and 2.1%. Initially, complete occlusion was obtained in 68%, neck remnant in 23%, and incomplete occlusion in 9% of aneurysms. Follow-up (mean 11 months) was obtained in 119 aneurysms and showed major recanalisation--that required re-treatment--in 13 cases (11%) and minor recanalisation in 17 cases (14.3%). CONCLUSION: Our findings suggest that new endovascular techniques allow proposing EVT as first-intention treatment in 87.3% of patients with intracranial aneurysms. This therapeutic strategy is associated with good clinical results. However, anatomical results are not improved and remain the EVT limiting factor.


Subject(s)
Angioplasty , Embolization, Therapeutic , Intracranial Aneurysm/therapy , Adolescent , Adult , Aged , Aged, 80 and over , Cohort Studies , Female , Humans , Intracranial Aneurysm/pathology , Male , Middle Aged , Treatment Outcome
19.
Prev Vet Med ; 80(2-3): 230-40, 2007 Jul 16.
Article in English | MEDLINE | ID: mdl-17386950

ABSTRACT

This article describes the use of Markov chains to explore the time-patterns of antimicrobial exposure in broiler poultry. The transition in antimicrobial exposure status (exposed/not exposed to an antimicrobial, with a distinction between exposures to the different antimicrobial classes) in extensive data collected in broiler chicken flocks from November 2003 onwards, was investigated. All Markov chains were first-order chains. Mortality rate, geographical location and slaughter semester were sources of heterogeneity between transition matrices. Transitions towards a 'no antimicrobial' exposure state were highly predominant, whatever the initial state. From a 'no antimicrobial' exposure state, the transition to beta-lactams was predominant among transitions to an antimicrobial exposure state. Transitions between antimicrobial classes were rare and variable. Switches between antimicrobial classes and repeats of a particular class were both observed. Application of Markov chains analysis to the database of the nation-wide antimicrobial resistance monitoring programme pointed out that transition probabilities between antimicrobial exposure states increased with the number of resistances in Escherichia coli strains.


Subject(s)
Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/classification , Chickens , Markov Chains , Poultry Diseases/drug therapy , Animals , Drug Resistance, Bacterial , Poultry Diseases/microbiology , Time Factors
20.
Res Vet Sci ; 80(3): 324-35, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16126240

ABSTRACT

The objective of the study was to compare the in vitro activity of marbofloxacin against Escherichia coli (E. coli) strains with differing marbofloxacin susceptibility levels under optimal growth conditions and under condition mimicking faecal environment in time-kill kinetic studies. Under optimal growth conditions, marbofloxacin exerted a bactericidal concentration-dependent activity against all E. coli strains with bactericidal concentrations equal to 1 or 4 times MIC. Under faecal growth conditions, marbofloxacin maintained a bactericidal concentration-dependent activity but a 4- to 16-fold increase in bactericidal concentration was required to produce a similar magnitude of effect at 8 h. The bactericidal activity decreased between 8 and 24 h and allowed a residual bacterial population to subsist with a significant regrowth for some of them. Under no-growth conditions, marbofloxacin produced a very low decrease of non-dividing bacteria during a short time. No concentration produced a reduction > or = 3log10 in viable count excepted for two susceptible strains at concentration > or = 64 x MIC after 4 h exposure. The pharmacodynamic parameters from time-kill kinetic studies provide a useful means of studying antimicrobial activity. The importance of using different growth conditions is indicated by the difference in the killing of E. coli in the absence of active dividing cells and in the presence of autoclaved faecal content, both of which have a detrimental effect on the activity of marbofloxacin.


Subject(s)
Anti-Bacterial Agents/pharmacology , Escherichia coli Infections/veterinary , Escherichia coli/drug effects , Fluoroquinolones/pharmacology , Poultry Diseases/microbiology , Quinolones/pharmacology , Swine Diseases/microbiology , Animals , Anti-Bacterial Agents/pharmacokinetics , Area Under Curve , Escherichia coli/growth & development , Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Feces/microbiology , Fluoroquinolones/pharmacokinetics , Microbial Sensitivity Tests/veterinary , Quinolones/pharmacokinetics , Swine , Turkeys
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