[Directly... from Florence. Third European Conference on Travel Medicine].
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Medicine↗
Biomedical subjects
R Michel
Publications and source records attributed to R Michel.
[Everything (or almost everything) about the Kappa coefficient].
Sensitivity, specificity, and predictive value are the standard parameters used to evaluate the efficacy of diagnostic tests. However all three parameters assume the existence of a gold standard test. Thus the problem arises as to what method to use in the absence of a benchmark. The solution involves assessment of agreement between two raters. This article based on an example drawn from an African setting describes the value and computation of the most widely used tool for assessing agreement and reproducibility of measures, i.e., the kappa coefficient.
Statistics, Nonparametric↗
Enlarged Chlamydia-like organisms as spontaneous infection of Acanthamoeba castellanii.
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Acanthamoeba↗
Members of the Cytophaga-Flavobacterium-Bacteroides phylum as intracellular bacteria of acanthamoebae: proposal of 'Candidatus Amoebophilus asiaticus'.
Three Gram-negative, rod-shaped bacteria that were found intracellularly in two environmental and one clinical Acanthamoeba sp. isolates were analysed. Two endocytobionts showing a parasitic behaviour were propagated successfully outside their amoebal host cells and were identified subsequently by comparative 16S rRNA sequence analysis as being most closely affiliated with Flavobacterium succinicans (99% 16S rRNA sequence similarity) or Flavobacterium johnsoniae (98% 16S rRNA sequence similarity). One endocytobiont could neither be cultivated outside its original Acanthamoeba host (Acanthamoeba sp. TUMSJ-321) nor transferred into other amoebae. Electron microscopy revealed that the amoebal trophozoites and cysts were almost completely filled with cells of this endosymbiont which are surrounded by a host-derived membrane. According to 16S rRNA sequence analysis, this endosymbiont could also be assigned to the Cytophaga-Flavobacterium-Bacteroides (CFB) phylum, but was not closely affiliated to any recognized species within this phylogenetic group (less than 82% 16S rRNA sequence similarity). Identity and intracellular localization of this endosymbiont were confirmed by application of a specific fluorescently labelled 16S rRNA-targeted probe. Based on these findings, we propose classification of this obligate Acanthamoeba endosymbiont as 'Candidatus Amoebophilus asiaticus'. Comparative 18S rRNA sequence analysis of the host of 'Candidatus Amoebophilus asiaticus' revealed its membership with Acanthamoeba 18S rDNA sequence type T4 that comprises the majority of all Acanthamoeba isolates.
Acanthamoeba↗
Development of 18S rRNA-targeted oligonucleotide probes for specific detection of Hartmannella and Naegleria in Legionella-positive environmental samples.
Aquatic protozoa are natural hosts of the human pathogen Legionella pneumophila. The fluorescence labeled 16S rRNA-targeted oligonucleotide probe LEGPNE1 has recently been shown to specifically detect extracellular legionellae as well as intracellular legionellae parasitizing protozoa. In this study we designed oligonucleotide probes which are complementary to distinct regions of the 18S rRNA of the Legionella host organisms of the genera Hartmannella and Naegleria. The specificity of the probes, HART498 and NAEG1088, was tested by in situ hybridization of various laboratory reference strains. In order to evaluate the fluorescent probes for environmental studies three selected Legionella-positive cold water habitats were examined for the presence of these protozoa. Traditional culture methods followed by morphological identification revealed an almost consistent presence of Naegleria spp. in cold water habitats. Other protozoa species including Acanthamoeba spp., Echinamoeba spp., Hartmannella spp., Platyamoeba placida, Saccamoeba spp., Thecamoeba quadrilineata, and Vexillifera spp. were found sporadically. Concomitant analysis of the pH, conductivity and temperature of the water samples revealed no preference of Legionella or the respective protozoa for certain environmental conditions. The specificity of the newly designed 18S rRNA probes demonstrates that they are valuable and rapid tools for the identification of culturable environmental protozoa.
Animals↗
Distribution of free-living amoebae (FLA) during preparation and supply of drinking water.
Free-living amoebae (FLA) are widely distributed in aquatic environments with increasing importance in hygienic, medical and ecological relationship to man. Only few data are available about abundances of these protozoa in the treatment of drinking water and standards in the management of water quality are not suitable for detection of FLA. Prevalence of FLA were investigated within six selected German drinking water treatment plants in the course of the purification-process of surface water and in a subsequent drinking water supply. The data give a short survey about the prevalence and reduction of FLA in processing and supply of drinking water.
Amoeba↗
Tracking occupational doses of transient workers.
A number of radioactive material licensees in the United States are unaware that they are required to track the occupational doses their radiation workers receive outside thieir facilities. As a result, these licensees may be cited for not tracking offsite occupational doses and quite possible for allowing some individuals to exceed the annual limits established by regulatory agencies. The accounting of occupational doses to "transient" workers is a difficult task. Unfortunately, written guidance to assist licensees on how to properly address this issue is not available. This paper was developed to raise awareness among radiation safety professionals of the need to establish effective measures to properly track transient worker exposures and maintain compliance with regulatory limits.
Humans↗
Colonic diversion for intractable constipation in children: colonic manometry helps guide clinical decisions.
BACKGROUND: Colonic manometry helps discriminate functional and behavioral causes for childhood constipation from colonic neuromuscular disease. METHODS: Of 375 colonic manometries performed for clinical indications, 12 could not be interpreted because of chronic colonic dilation. Based on colonic manometries that showed either no contractions or an absence of the gastrocolonic response or an absence of high-amplitude propagating contractions, the authors recommended diverting colostomies or ileostomies in 12 chronically constipated children (mean age, 4 years; range, 2-14 years, 5 boys). Before study, medical treatment was ineffective in all children. These children had persistently dilated colons with pathologic diagnoses of intestinal neuronal dysplasia (n = 4), hypoganglionosis (n = 2), hollow visceral myopathy (n = 1), and normal (n = 5). RESULTS: Six to 30 months after diversion, the authors restudied all the children. Eleven of 12 diverted colons were no longer dilated. In two patients, abnormal motility involving the entire colon was unchanged from the initial study, small bowel motility was abnormal, and we recommended no further surgery. In two cases, the colon remained abnormal but small bowel motility was normal, and we recommended subtotal colectomy and ileoproctostomy. In four cases, the left colon remained abnormal, but the right colon was normal, and we recommended reanastomosis after left hemicolectomy. In four cases, motility in the diverted colons was normal, including a gastrocolonic response and high-amplitude propagating contractions, and the authors recommended reanastomosis. Defecation problems resolved in 10 of 12 when followed up 5 to 30 months after treatment. CONCLUSION: These data suggest that in some cases of intractable childhood constipation associated with colonic distention, temporary diversion improved colonic motility. Colonic manometry may be used to predict which patients will benefit from resection or reanastomosis.
Adolescent↗
[Antimalarial chemoprophylaxis in the French army: development from 1986 to 2001].
In 1999, almost 25,000 French soldiers were deployed in malaria transmission areas. With an incidence of 4.5 p. 100 men.year, malaria infection remains a serious problem requiring priority status for control in military personnel. Epidemiological surveillance provides data necessary to assess morbidity due to malaria, monitor changing patterns of Plasmodium falciparum drug-sensitivity, and evaluate the efficacy of malaria control measures. In 1990, the French army replaced chemoprophylaxis using chloroquine alone with combination treatment using a single capsule containing 100 mg of chloroquine base and 200 mg of proguanil chlorhydrate. This measure in association with the use deltamethrine impregnated bed-nets led to a significant decrease in incidence. However a comeback was observed from 1993 to 1997. Since 1995, the effectiveness of the chloroquine-proguanil combination has diminished mainly in the stable malaria areas. In response to increasing Plasmodium falciparum resistance to chloroquine-proguanil chemoprophylaxis, it was necessary to find an alternative. Two studies carried out among French soldiers in Sub-Saharian Africa between 1996 and 1998 demonstrated that a daily dose 100 mg doxycycline was more effective than the chloroquine-proguanil combination. In addition the 1998 study showed that doxycycline monohydrate in the form of a multiparticle tablet was better tolerated. In 2001 four drugs are used for malaria chemoprophylaxis in the army personnel, i.e., chloroquine and proguanil in combination, mefloquine, and doxycycline, depending on location and duration of mission. The chloroquine-proguanil combination is used in countries with chloroquine-resistant strains, e.g., Chad and Senegal. Mefloquine and doxycycline are used in countries with chloroquine-resistant strains. Due to increasing resistance, it will be necessary to evaluate other drugs or antipaludian combinations.
Animals↗
[Disease vector control strategy in the French army].
Disease vector control is a major priority for the Medical Health Corps of the French Armed Forces which maintains around 23,000 troops in tropical areas and is involved in numerous military and humanitarian missions throughout the world. Control strategy includes both general and personal control measures. Personal control measures include wearing permetherin-impregnated combat uniforms, application of repellents to the skin, and use of deltamethrin-impregnated bednets. General measures are implemented in facilities and in the environment. Measures in facilities include not only physical deterrents such as screens on openings and air-conditioning but also application of chemical insecticides to walls, curtains, and screening. Environmental measures include control of larval deposits and elimination of potential breeding areas. Low-volume wide-area spraying of imagocides is a supplemental option used in case of disease outbreak. For units stationed in tropical areas, command and surveillance of vector control operations is under the responsibility of the mosquito control committee which includes personnel from the affected field unit. Strategies are chosen in function of local climate and operational conditions. The efficacy of vector control programs is assessed annually by reviewing the incidence in armed forces personnel of the main vector-transmitted diseases: malaria, dengue fever, and leishmaniasis. Documentation and training are dispensed to all units stationed in tropical areas. To ensure that knowledge of military physicians remains current, three courses on malaria control are offered each year at the Tropical Medicine Institute of the Armed Forces Health Corps (Le Pharo) in Marseille. Field research conducted in collaboration with military or civilian organizations independent of the Armed Services Health Corps makes it possible to keep chiefs of staff informed of state-of-the art vector control measures adapted to use by personnel on assignment or mission in tropical areas.
Animals↗
[Epidemiologic surveillance of dengue fever in the French army from 1996 to 1999].
Dengue fever is a widespread disease that can occur outside tropical areas. Several thousand French military personnel are exposed to this infectious risk each year and exposure is expected to rise with the creation of a professional army and the increasing number of foreign missions. As a result, dengue fever has become a major priority for the Armed Services Health Corps (ASHC). A system of epidemiological surveillance based on the active participation of all military physicians has been designed by the ASHC to collect and analyze all data relevant to cases of dengue fever involving French military personnel stationed overseas or at home. The purpose of this study is to present data compiled for the period from 1996 to 1999. Analysis of these data demonstrated that the incidence of dengue fever peaked in 1997 due to epidemic outbreaks occurring in French Polynesia and Martinique. In response to these outbreaks control measures were adapted especially in regard to vector control. This study shows that the system of surveillance implemented by the ASHC is an effective but still perfectible tool.
Adult↗
[Typhoid fever epidemic in the Ivory Coast in vaccinated French military personnel].
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Adult↗
Vannella sp. harboring Microsporidia-like organisms isolated from the contact lens and inflamed eye of a female keratitis patient.
Viable Hartmannella sp. and two strains of Vannella sp.--but no Acanthamoebae--multiplied on NN-agar inoculated with pieces of the contact lens from a female keratitis patient. Within the cytoplasm of one Vannella isolate, intracellular parasites could be observed whose earliest stages were developing within the nucleus, resembling those Microsporidia-like parasites seen within Vannella isolated recently from a warm tapwater system. This assumption was also confirmed by electron microscopy. In swabs taken directly from the cornea, Pseudomonas aeruginosa were identified, but they did not yield any growth of amebas in culture. However, cocultivation of parasite-free Vannella strains with the above-mentioned swab matter resulted in infected amebas harboring the same intracellular parasites seen before. This infection could be established only if the corresponding spores were present as infective agents in the swab matter. The successful treatment of the patient with antibiotics supports the assumption that P. aeruginosa was the main cause of the corneal ulceration. The extent to which the Microsporidia-like organisms may have been involved in the development of keratitis remains a matter of discussion.
Adult↗
Managing a sound portable gauge radiation safety program.
At some construction engineering companies, individuals with no background in radiation safety sometimes are assigned the not always welcome title of Radiation Safety Officer (RSO). With this new title comes the responsibility of ensuring that portable gauges are used safely at their facilities and in tile field. These newly appointed RSOs sometimes lack the knowledge and experience needed to manage a radiation safety program. This article was developed to provide the basic information needed to work confidently and safely around these instruments and to discuss licensing requirements and other information pertaining to the management of a portable gauge radiation safety program.
California↗
Effective dose equivalent estimates in diagnostic radiology with single dosimetry.
In many external exposure situations dose estimates obtained from personal monitors significantly overestimate the Effective Dose Equivalent (EDE). This occurs particularly when the body is not uniformly exposed due to the irradiation conditions or due to protective shielding (i.e., lead apron) of portions of the body (NCRP 1995). Many numerical relationships between monitoring data and EDE have been proposed to perform more accurate dose estimates (Gill et al. 1980; Faulkner and Harrison 1988; Webster 1989; Niklason et al. 1994; Berger et al. 1995). Also, organizations such as the Conference of Radiation Control Program Directors (CRCPD), the National Council on Radiation Protection and Measurements (NCRP) and the Electric Power Research Institute (EPRI) have published recommendations on this subject (CRCPD 1995; NCRP 1995; EPRI 1998). Before implementing the use of any of the proposed relationships, they should be thoroughly reviewed so that proper practices are chosen and monitoring data are properly evaluated. It is also important for each facility to be aware of the regulatory requirements in their state such as if the methodology is approved for use, which method and for whom can the EDE be applied. The United States Nuclear Regulatory Agency (NRC) does not currently permit dose weighting for any of its licensees. The EPRI study performed in 1997 was initiated by the NRC to determine how viable dose weighting would be, and for which NRC licensee population. This paper discusses numerical relationships for external exposure in diagnostic radiology for estimating EDE in a single-monitor program.
Diagnostic Imaging↗
Managing a sound industrial radiography radiation safety program.
This article was developed to provide new radiation safety officers with the basic information needed for ensuring safety, security, and control of industrial radiography sources and to discuss licensing requirements and other information pertaining to the management of radiation safety programs associated with these sources.
Humans↗
'Candidatus Odyssella thessalonicensis' gen. nov., sp. nov., an obligate intracellular parasite of Acanthamoeba species.
An intracellular bacterium, strain L13, was observed infecting an environmental isolate of an Acanthamoeba species. The bacterium could not be recovered on axenic medium but was recovered and cultivated in vitro using cultures of Acanthamoeba polyphaga. The 16S rRNA gene sequence of L13 was found to be new, sharing less than 84% similarity with other sequences in the GenBank/EMBL database. L13 was found to be a member of the alpha-Proteobacteria, sharing an evolutionary line of descent with a group of uniquely obligate intracellular organisms comprised of Caedibacter and Holospora species and the NHP bacterium. Viable bacteria appeared to be highly motile within amoebae. Ultrastructural analysis of the bacterium demonstrated that it is rod-shaped and possesses a typical Gram-negative cell wall, but has no other outstanding features except small vesicle-like structures often associated with the outer surface of each bacterium. The host range of L13 was found to be limited to the genus Acanthamoeba. In A. polyphaga, L13 infection was slow to manifest when cultures were incubated below 30 degrees C, but at higher temperatures bacteria multiplied prolifically and induced host cell lysis. The protein profile of the bacterium purified from the amoebae was assessed by SDS-PAGE and its G+C content was estimated to be 41 mol%. Although these results support the proposal of L13 as a new species, its obligate intracellular nature prevented isolation of a definitive type strain. L13 is therefore proposed as 'Candidatus Odyssella thessalonicensis' gen. nov., sp. nov.
Acanthamoeba↗
[Transesophageal echocardiography as a standard examination in sepsis?].
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Catheterization, Peripheral↗