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The epidemiology of animal trypanosomosis around Bobo-Dioulasso (Burkina Faso, West Africa) benefited a lot in the last years from the progress of molecular tools. The two most used molecular techniques were the polymerase chain reaction for the diagnosis of the disease in cattle and the characterization of the trypanosomes in the host and the vector on one hand, and the microsatellite DNA polymorphism in tsetse flies to study the intraspecific genetic variability of the vector on the other hand. The results obtained in the Sideradougou area during a recent two year survey with these techniques, associated with many other georeferenced informations concerning vector and cattle distribution, natural environment, landuse, ground occupation, livestock management, were combined in a Geographical Information System. This new approach of a complex pathogenic system led to a better evaluation of the risk of trypanosome transmission.

Background: Although malaria remains one of the major public health threats in inter-tropical areas, there is limited understanding of imported malaria in children by paediatricians and emergency practitioners in non-endemic countries, often resulting in misdiagnosis and inadequate treatment. Moreover, classical treatments (atovaquone-proguanil, quinine, mefloquine) are limited either by lengthy treatment courses or by side effects. Since 2010, the World Health Organization (WHO) has recommended the use of oral artemisinin-based combination therapy for the treatment of uncomplicated Plasmodium falciparum malaria worldwide. The benefits of artenimol-piperaquine in children have been validated in endemic countries but experience remains limited in cases of imported malaria., Methods: This prospective observational study in routine paediatric care took place at the Emergency Department, Robert-Debré Hospital (Paris, France) from September 2012 to December 2014. Tolerance and efficacy of artenimol-piperaquine in children presenting with the following inclusion criteria were assessed: P. falciparum positive on thin or thick blood smear; and the absence of WHO-defined features of severity., Results: Among 83 children included in this study, treatment with artenimol-piperaquine was successful in 82 children (98.8%). None of the adverse events were severe and all were considered mild with no significant clinical impact. This also applied to cardiological adverse events despite a significant increase of the mean post-treatment QTc interval., Conclusion: Artenimol-piperaquine displays a satisfying efficacy and tolerance profile as a first-line treatment for children with imported uncomplicated falciparum malaria and only necessitates three once-daily oral intakes of the medication. Comparative studies versus artemether-lumefantrine or atovaquone-proguanil would be useful to confirm the results of this study.

Post-malaria neurologic syndrome (PMNS) is a rare complication following a Plasmodium falciparum infection and its pathophysiology remains unclear. This is the first report of a pediatric PMNS following an infection acquired in Africa and the fourth description of pediatric PMNS overall. Neither intrathecal synthesis of Immunoglobin G nor specific P. falciparum antibodies were found in the cerebrospinal fluid.

Background: Functional gastrointestinal disorders and migraine are both common causes of medical attention. We have previously shown an association between migraine and infant colic. In this case-control study, we aimed to establish whether there is an association between migraine and other functional gastrointestinal disorders in children and adolescents., Methods: We included children and adolescents aged 6-17 years presenting to the emergency department of four tertiary hospitals in France and Italy. Patients diagnosed with either migraine or tension-type headache by the hospital's paediatric neurologist were enrolled as cases. Patients presenting to the emergency department with minor trauma and no history of recurrent headache were enrolled as controls. Investigators masked to a patient's group allocation diagnosed functional gastrointestinal disorders using the Rome III diagnostic criteria. Univariable and multivariable analyses were done to identify specific disorders and baseline factors associated with migraines and tension-type headache., Findings: Between Nov 1, 2014, and Jan 31, 2015, we enrolled 648 controls and 424 cases (257 patients with migraine and 167 with tension-type headache). 83 (32%) children and adolescents in the migraine group were diagnosed with functional gastrointestinal disorders compared with 118 (18%) in the control group (p<0·0001). Multivariable logistic regression showed a significant association between migraine and three gastrointestinal disorders: functional dyspepsia (odds ratio 10·76, 95% CI 3·52-32·85; p<0·0001), irritable bowel syndrome (3·47, 1·81-6·62; p=0·0002), and abdominal migraine (5·87, 1·95-17·69; p=0·002). By contrast, there was an inverse association between migraine and functional constipation (0·34, 0·14-0·84, p=0·02). 41 (25%) participants with tension-type headache had functional gastrointestinal disorders, which did not significantly differ from the prevalence of these disorders in the control group (p=0·07); no significant association was noted between any functional gastrointestinal disease and tension-type headaches., Interpretation: Three abdominal-pain-related functional gastrointestinal disorders were associated with migraine in children and adolescents. These findings are of value to the diagnosis and management of these common diseases. Future studies should investigate whether antimigraine drugs are of benefit in functional gastrointestinal disorders., Funding: None., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Quinine was the main treatment for malaria between 1630 and the beginning of the XXth century. In the 1940s, the synthesis of chloroquine gave rise to the hope of eliminating this plague. Falciparum resistance to chloroquine, first observed in Asia then in sub-Saharan Africa, lead researchers to discover halofantrine, mefloquine, atovaquone-proguanil and artemisinin combined therapies. There is no ideal treatment for uncomplicated imported malaria in children. Medical teams have to develop a protocol according to available drugs and their personal experience, with a special attention to follow-up at days 3-4 and day 28. From now on, severe malaria must be treated with intravenous artesunate, a more effective therapy than quinine., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Thousands of street children of Manila are affected by early-in-life oral infection. The aim of the present investigation was to evaluate the effectiveness of a sea-salt mouthrinse solution in street children of Manila affected by mild to severe forms of periodontal disease. These children were all in need of special protection: abandoned, abused, exploited, neglected, orphaned, poor. During 3 oral-health missions in 2003, 2004 and 2005, 617 abandoned children (5 to 13 year-old), received oral examination at a non-sectarian child-caring institution in Metro Manila (Virlanie Foundation) by calibrated examiners. A treatment based on what could be done was proposed: 1. Teaching of a precise tooth brushing technique with sea-salt, controlled and reinforced every two days for one week by calibrated health educators, 2. The application of sea-salt water mouthrinse (2.5 gram in 20 ml). Periodontal measurements were repeated at the end of each mission. All children returned to child-caring institution for the followup examinations. In 2003, 10 male and 11 female (n=21) were diagnosed with aggressive periodontitis. In 2009 and 2010, none was affected by aggressive periodontitis. For all patients, the gingival index decreased from 1.08 at the first mission to 1.04 at the end of the second mission and 0.98 at the end of the third mission. The periodontal index decreased from 1.33 at the first mission to 0.98 at the second mission and 0.92 at the last mission. The present investigation confirms that prevention and early diagnosis can result in success with minimum cost. The provided oral health program empowered street children in the most desperate circumstances to be educated and become self-reliant, independent, and responsible. We propose here an antimicrobial approach which has a high degree of efficacy and tolerability, and can be implemented in virtually all parts of the world using low-cost resources.

The epidemiology of vector-borne diseases is complex due to the variability in the ecology of the different actors involved, i.e. hosts, parasites and vectors. The transmission of African animal trypanosomosis in the West-African savannah region is an excellent example of this complexity: riverine tsetse flies have an heterogeneous distribution along the rivers, depending of suitable habitats, and transmit pathogenic trypanosomes were they use domestic animal as feeding hosts. Contrasting epidemiological situations may thus occur at the local scale, and a broad view of the overall environment is necessary to quantify the interfaces in time and space between hosts and vectors. Geographical Information Systems (GIS) can provide new insight into the study of such complex epidemiological processes. GIS is a powerful technology that has been used mainly in map-making, and an enormous amount of knowledge can be gained simply by geographical data projection. GIS also allows juxtaposition of different types of information, creation of new variables, testing of theories and correlation, and generating of predictive models. The purpose of the present paper is to exemplify the potential application of GIS using a recent study carried out on animal trypanosomosis in a cattle-raising area of Burkina Faso.

The goal of periodontal treatments is to eliminate bacteria and their products without damaging cementum surfaces. Nonsurgical treatments are often limited by the inability of curettes to access the most apical zone of the pocket. While ultrasonic mini-inserts have been used for nearly 10 years now, their effect on dental tissues has not been tested. The purpose of the present study was to compare a new series of mini-inserts to Gracey curettes, which are the reference in nonsurgical treatments. Two experienced periodontists conducted root treatments on teeth destined for extraction using regular clinical criteria. One face of each root was instrumented using a Gracey curette, and the opposite face was instrumented using an ultrasonic mini-insert. After the instrumentation procedure, the teeth were prepared for examination by secondary electron (topographic features) and backscattered electron (organic and mineral composition) microscopy. Differences in surface composition between teeth treated by the two periodontists were noted and were related to the lateral pressure exerted. Calculus removal was less effective when strong lateral pressure was exerted using the ultrasonic mini-inserts, while more cementum was removed and more scratching occurred with both manual and ultrasonic instruments. In all cases, the ultrasonic mini-inserts allowed greater apical access. The new ultrasonic mini-inserts were as effective as manual curettes in eliminating plaque and calculus. The shape of the mini-inserts made them more effective in apical zones. The amount of damage to the cementum depended on the lateral pressure exerted by the periodontist.

Mucoidy and cytotoxicity arise from two independent modifications of the phenotype of the bacterium Pseudomonas aeruginosa that contribute to the mortality and morbidity of cystic fibrosis. We show that, even though the transcriptional regulatory networks controlling both processes are quite different from a molecular or mechanistic point of view, they may be identical from a dynamic point of view: epigenesis may in both cases be the cause of the acquisition of these new phenotypes. This was highlighted by the identity of formal graphs modelling these networks. A mathematical framework based on formal methods from computer science was defined and implemented with a software environment. It allows an easy and rigorous validation and certification of these models and of the experimental methods that can be proposed to falsify or validate the underlying hypothesis.

Human African trypanosomosis (HAT) remains a major public health problem in Subsaharan Africa. The region around the town of Bonon in middle western Côte d'Ivoire is a highly endemic HAT zone. The purpose of this study was to assess the role of travelling of infected patients in transmission of HAT. The study population included a total of 96 patients in whom HAT had been diagnosed actively or passively between 1999 and 2000. Information on each patient's residence and workplaces, i.e. water site, and farm field, was used to calculate the mean distance traveled and mean number of places visited daily by each patient. Findings indicated that both parameters, i.e., distance traveled and number of places visited, were significantly higher for patients living in Bonon than those living in hamlets or homesteads. Based on analysis of patient movements the endemic zone could be divided into three subdivisions with different modes of disease transmission. This study was performed as a preliminary step for a larger investigation designed to allow specific targeting of HAT hot spots based mainly on a geographic information system.

Modelling of the spatial distribution of bovine trypanosomosis prevalence in Sideradougou district Burkina Faso was performed by using a combination of spatial and statistical analysis. Based on a comprehensive and geographically representative census of herds and farms in the area, more than 2000 cattle were randomly chosen and their blood sampled during field survey. Data on livestock farming practices were recorded for each farm. All data were mapped within a GIS to generate new information on spatial constraints in the area. Surveys results were analysed and serological prevalence data were modelled using logistic regression. The model allowed identification and quantification of risk factors. In a second step the statistical model was used predictively on the entire farm population in the area. This method was successful in predicting the serological prevalence for each individual herd in the sample, from their livestock management patterns and spatial location. Predicted prevalences were represented within the GIS, taking daily movements of animals into account. Spatial distribution of prevalence would illustrate specific locations at risk from an epidemiological viewpoint. It gives evidence that the hydrological network and land occupation patterns in the savanna-type countryside are playing an important part when structuring a so-called "trypanosomosis space".

Purpose: The purpose of this prospective multicenter study was to evaluate the efficacy of 3i threaded implants for the treatment of edentulous patients in a 1- to 5-year period. This article reports the total data and global results of 3 threaded designs of 3i implants: self-tapping, ICE, and Osseotite., Materials and Methods: A total of 1,583 implants (619 ICE, 545 Osseotite, and 419 self-tapping) were placed between 1995 and 1999 in 528 patients at 13 European clinical centers. The average age of the patients was 53.6 years. Clinical and radiographic evaluations were performed annually for up to 5 years., Results: Of the total implants, 707 were placed in the maxilla and 876 in the mandible. A total of 1,162 implants were placed in posterior segments. Forty-eight implants were lost to follow-up and 55 were failures. The most frequent prosthetic indication was the short-span fixed prosthesis (440 cases), followed by 172 single-tooth replacements, 56 long-span prostheses, and 4 overdentures. Radiographic evaluation after 6, 12, and 24 months of implant loading showed, respectively, mean crestal bone loss of 0.04 +/- 1.3 mm, 0.12 +/- 1.6 mm, and 0.2 +/- 1.7 mm. A cumulative survival rate of 96.5% was observed 5 years after implant placement, with 97.2% survival in the maxilla and 95.8% in the mandible. The survival rate was similar in anterior (96.7%) and posterior (96.5%) segments., Discussion: A total of 55 failures were reported in this study with 47 early failures and 8 late failures. The rate of late failures is of utmost importance for the restorative dentist., Conclusion: This clinical study gives evidence of very high success rates using 3 threaded designs of 3i implants.

The size of tsetse flies is often associated with population dynamics and vectorial capacity parameters. Adult fly size is generally estimated from measurements of wing segments. To take measure of the wing, a semi-automatic software was developed by CIRAD-EMVT and IRD. It was used in wild populations of Glossina tachinoides Westwood and G. palpalis gambiensis Vanderplank (Diptera: Glossinidae) trapped near Bobo-Dioulasso, Burkina Faso. From an numeric picture of the wing, the software calculates the length of vein segments, the ratios between these lengths, the surface of the tsetse characteristic "hatchet cell", and the greyness on the wings. The data were interesting at the level of taxonomy. In addition, they help specify physiological characteristics of the studied populations.

Recent studies in a rangeland area of Burkina Faso showed that riparian tsetse flies (Glossina tachinoides and G. palpalis gambiensis) were found along the main rivers, but depending on their location, they had different hosts and were not infected by the same trypanosomoses. There were different epidemiological situations within a distance of a few kilometres, and local assessment of the trypanosome risk thus called for a global approach taking account of the environmental and human factors involved in the interfaces between hosts and vectors. Various types of information concerning entomology, parasitology, ecology, land occupation and animal production systems were fed into a Geographical Information System. High spatial resolution remote sensing tools and original modelling methods were used to detect the valley landscapes most favourable to tsetse flies, and describe land use by herds. The impact of trypanosomes appeared to depend largely on animal movements, watering practices and the degree of contact with riparian tsetse flies. Linking these types of information revealed the most dangerous sites in epidemiological terms, which in this case represented some 18% of the network initially surveyed.

Expression in Escherichia coli of the Myxococcus xanthus gene celA, which encodes an extracellular endoglucanase, resulted in CelA being distributed between cytoplasm, periplasm and membrane. The presence of an adjacent open reading frame downstream from the full celA gene, or the absence of a putative lipoprotein signal sequence, confined CelA distribution to the periplasm and membrane, or to the cytoplasm and periplasm, respectively.

The epidemiology of vector-borne diseases is complex due to variability in the ecology of the different actors involved, i.e., hosts, parasites and vectors. Transmission of animal trypanosomiasis in the West African savannah region is an excellent example of this complexity. Because of the importance of place and time in determining the interface between host and vector, a broad view of the overall environment is necessary to understand the variety of situations that can be encountered in an epidemiological system. Spatial distribution is a key factor for risk evaluation. State-of-the-art geographic information systems (GIS) have provided new insight into this complex epidemiology. GIS is a powerful technology that has been used mainly in map-making. An enormous amount of knowledge can be gained simply by geographical data projection. However GIS also allows juxtaposition of different types of information, creation of new variables, testing of theories and correlations, and generation of predictive models. The purpose of this article is to exemplify the potential applications of GIS using a recent study carried out on animal trypanosomiasis in a cattle-raising area of Burkina Faso.

Several extracellular enzymes that are responsible for plant tissue maceration were detected in culture supernatant of the psychrotrophic bacterium Chryseomonas luteola MFCL0. Isoelectrofocusing experiments showed that pectate lyase (PL) activity resulted from the cumulative action of three major isoenzymes, designated PLI, PLII, and PLIII. Cellulolytic activity was also detected in culture supernatants. These enzymes exhibited different behaviors with respect to growth temperature. PLII was not regulated by temperature, whereas PLI and PLIII were regulated similarly by growth temperature. Maximal levels of PLI and PLIII were produced at 14 degrees C when cells were grown in polygalacturonate-containing synthetic medium and at around 20 to 24 degrees C in nutrient broth. In contrast, thermoregulation of cellulolytic activity production differed from thermoregulation of PL. The level of cellulolytic activity was low in all media at temperatures up to 20 degrees C, and then it increased dramatically until the temperature was 28 degrees C, which is the optimal temperature for growth of C. luteola. Previously, we defined the critical temperature by using the modified Arrhenius equation to characterize bacterial behavior. This approach consists of monitoring changes in the maximal specific growth rate as a function of temperature. Our most striking result was the finding that the temperature at which maximum levels of PLI and PLIII were produced in two different media was the same as the critical temperature for growth observed in these two media.

Random transcription fusion delivery, with bacterial luciferase genes as reporter, was performed in the psychrotrophic bacterium Pseudomonas fluorescens. Direct screening on plates of the insertions allowed the isolation of fusions into thermoregulated genes with good accuracy, either in a library of insertion fusions, or after genetic transfer of a putative regulatory mutation. Using this method, it was shown that in Ps. fluorescens, nearly 40% of the genes are thermoregulated and belong to at least three classes according to the maximal temperature of expression of the fused genes. This is more than had been estimated by a previous method, and demonstrates the importance of thermoregulation in psychrotrophic bacteria. As this reporter is the first to be used for direct screening for genes regulated by temperature, it should be of great value in the study of mechanisms involved in adaptation to this environmental factor.

African animal trypanosomoses constitute the most important vector-borne cattle diseases in sub-Saharan Africa. Generally it is considered that there is a great lack of accurate tools for the diagnosis of the disease. During a trypanosomosis survey in the agro-pastoral zone of Sideradougou, Burkina Faso, 1036 cattle were examined for trypanosomes using microscopy. The PCR was applied on a subset of 260 buffy-coat samples using primers specific for Trypanosoma congolense savannah and riverine-forest groups, T. vivax, and T. brucei. Parasitological examination and the molecular technique were compared, showing a better efficiency of the latter. In the near future, the PCR is likely to become an efficient tool to estimate the prevalence of African trypanosomoses in affected areas.

In the psychrotrophic bacterium Pseudomonas fluorescens, some genes are thermoregulated: they are maximally expressed at a particular temperature within the broad range of temperatures that allow growth of this bacterium. To study this regulation, random transcriptional insertion fusions were obtained by means of mini-Tn5lacZ1 or mini-Tn5luxAB transposition. One fusion was studied in which beta-galactosidase production was maximal at a low-growth temperature. The mutated gene (that we call xsf) was highly homologous to xseA from Escherichia coli (and from other bacteria) which encodes the large subunit of exonuclease VII. Genetic tools were constructed in order to analyse and manipulate this fusion: a plasmid derived from R68.45 was used for chromosome transfer and a replacement vector was constructed to allow in situ marker exchange of the mini-Tn5lacZ1 by an Hg(r) interposon. This vector was used to make double mutants and hence to study the effect of the insertion in xsf on the expression of other fusions. Six genes were thereby identified with a decreased expression in an xsf- background and with different characteristics of thermoregulation.

An endoglucanase, CelA, is secreted by Myxococcus xanthus only during exponential growth. The production of this enzyme is decreased by mutations in 5 different genes (Exc +/- phenotype), three of which correspond to asg genes which regulate the production of an early cell-to-cell signal in development. Transcription of celA is decreased in two of these Exc +/- mutants, whereas a post-transcriptional step is affected in two other Exc- mutants. Thus, asg genes, in addition to regulating the onset of development, also regulate a gene (celA) that is expressed during exponential growth and that is not involved in development.

The secretion of numerous proteins during vegetative growth of Myxococcus xanthus, and the multicellular development cycle induced upon starvation of these bacteria, are partially interrelated in so far as mutants impaired in extracellular protein production are unable to undergo development. We have cloned and sequenced a gene in which a Tn5 insertion leads to a decrease in the production of most, if not all, extracellular proteins, and prevents development and sporulation. The deduced protein is homologous to the putative ubiquinone-binding subunit of bacterial and mitochondrial NADH:ubiquinone oxidoreductases (complex I). This is the first example of the presence of this complex in a bacterium from subclass delta of the proteobacteria. This gene is expressed during growth and during early development. As its disruption by Tn5 does not impair growth of the mutant strain, we assume the presence of a second alternative NADH oxidoreductase, and suggest that the phenotypic alterations caused by the mutation are due to a decrease in the proton-motive force.

Two psychrotrophic toluene-degrading Pseudomonas putida strains were isolated at low temperature from a toluene-polluted soil, thereby demonstrating that toluene degradation at low temperature occurred in nature, a finding of possible interest for soil bioremediation procedures. In one of these strains, two aromatic compounds (toluene and benzoate) were degraded, most likely through different pathways. To study the effect of the growth temperature on the metabolism of these substrates, we studied the evolution of the maximal growth rates with respect to both temperature and substrate. It was shown that not only cardinal temperatures but also temperature characteristics deduced from the Arrhenius plot of maximal growth rates differed when the different substrates were used as sole carbon and energy source.

The variations in the maximal specific growth rate of the psychrotrophic bacterium Pseudomonas fluorescens MF0 with respect to temperature were studied between 0 and 30 degrees C (optimal for growth). The Arrhenius plot showed a drastic change in slope at the intermediate temperature of 17 degrees C. Over the cold domain from 0 to 17 degrees C, the temperature characteristic was twofold higher than over the suboptimal domain from 17 to 30 degrees C. The macromolecular composition of exponentially growing cells was invariant over the entire range from 0 to 30 degrees C. Variations of temperature and growth rate were independently investigated through chemostat experiments in order to characterize their respective effects on cell macromolecular composition and size. The effect of growth rate in this psychrotrophic strain is identical to that of all other bacteria assayed so far. In contrast, an original biphasic variation of total protein concentration was demonstrated in strain MF0 with respect to temperature, with a maximum at 17 to 20 degrees C. Indeed, increasing the temperature in the chemostat resulted in a biphasic decrease in the net protein production rate: a very slight decrease below 17 degrees C and a much larger decrease from 17 to 28 degrees C. These results could signify an increase in the cellular protein degradation rate with increasing temperature, especially above 17 degrees C.

A recombinant Myxococcus xanthus strain was constructed that constitutively produces two proteins from Escherichia coli, the cytoplasmic beta-galactosidase and the periplasmic pH 2.5 acid phosphatase (AppA protein). We have previously shown that during vegetative growth, AppA protein is partly accumulated in the periplasm of M. xanthus and partly released into the medium. We demonstrate here that during starvation-induced development, release of periplasmic AppA protein to the medium did not occur over a period of 20 h. This was coincident with, but not caused by, the arrest of the synthesis of the foreign proteins. We have shown that this lack of secretion could be attributed to starvation per se and did not depend on the ability of the cells to undergo development. Our findings suggest that protein secretion which occurs during the first hours of starvation-induced development might therefore take place via a different route from that which occurs in vegetative cells.

This work determined the levels of expression of CD11c by neutrophils (PMNs) collected from subjects with various periodontal conditions. The percentages of CD11c-positive crevicular fluid PMNs were significantly lower than those of peripheral blood PMNs, but the levels of CD11c expression were similar in PB-PMNs and CF-PMNs (P<0.001). On the other hand, no significant difference could be found between the groups, either for the percentages of CD11c-positive cells or for the CD11c expression levels.

A representative sample of 2020 schoolchildren, aged 6 to 15 years, was randomly selected from 85 state and private schools in Rennes and distributed in 10 groups, according to their age. Type and prevalence of dental injuries were determined in each group, using Ellis & Davey's classification, giving rise to a subset of 345 subjects. Simple enamel fracture was the predominant injury (59.4%), occurring most often on maxillary central incisors. Most time (77.1%), the trauma affected only one tooth. Mean prevalence of dental injuries was 13.6% from 2020 subjects. Boys showed a higher prevalence than girls (respectively 17% and 10.2%), but this difference was only significant for age-groups 12 and 13 (p < 0.001) and for the whole group of 6-15 (p < 0.001).

In this study, we assessed the LFA-1 (CD18/CD11a) and CR3 (CD18/CD11b) expression on peripheral polymorphonuclear leukocytes (PB-PMN) and crevicular fluid polymorphonuclear leukocytes (CF-PMN), by subjects with a healthy periodontium (n = 7), gingivitis (n = 8), early-onset periodontitis (n = 17) and adult periodontitis (n = 8). Using flow cytometry analysis, the %s of CD18, CD11a and CD11b positive cells and the absolute numbers of fluorescent molecules were determined. No significant difference could be found among the 4 groups, for these 2 kinds of parameters, in PB-PMN or CF-PMN. However, a great difference could be noted between the results obtained from PB-PMN and those obtained from CF-PMN. The %s of positive CF-PMN were significantly lower than those of PB-PMN for the 3 sub-units (p < 0.001). The levels of CD18 and CD11b expressed by CF-PMN were higher than those expressed by PB-PMN and the difference was significant for CD11b (p < 0.001). On the contrary, the level of CD11a expressed on CF-PMN was significantly lower than that expressed by PB-PMN (p < 0.001). Hence, our current results show that early-onset periodontitis PMN can be quite normal and this fact is not surprising insofar as, in our study, these cells were perfectly functional and all the subjects were in good health. We concluded that the analysis of the leukocyte adhesion receptors expression on PB-PMN does not appear useful for helping to establish a differential diagnosis between the different forms of periodontitis.(ABSTRACT TRUNCATED AT 250 WORDS)

After the demonstration that Stigmatella aurantiaca DW4 secretes an endo-N-acetyl-beta-D-glucosaminidase (ENGase), acting on the di-N-acetylchitobiosyl part of N-linked glycans (S. Bourgerie, Y. Karamanos, T. Grard, and R. Julien, J. Bacteriol. 176:6170-6174, 1994), an ENGase activity having the same substrate specificity was also found to be secreted during vegetative growth of Myxococcus xanthus DK1622. The activity decreased in mutants known to secrete less protein than the wild type (Exc +/-). During submerged development, the activity was produced in two steps: the first increase occurred during the aggregation phase, and the second one occurred much later, during spore formation. This production was lower in developmental mutants impairing cell-cell signaling, the late mutants (csg and dsg) being the most deficient. Finally, when sporulation was obtained either by starvation in liquid shake flask culture or by glycerol induction, the activity was produced exclusively by the wild-type cells during the maturation of the coat.

In the psychrotrophic bacterium Pseudomonas fluorescens, the production of several enzymes that otherwise differ in their cell location, growth phase production and inducibility appeared to be similarly regulated by the growth temperature. In order to determine the level of this regulation, the expression of the apo and lip genes encoding two of these enzymes, the acidic phosphatase and lipase, respectively, was studied at different temperatures. Both genes were optimally expressed at 17.5 degrees C, i.e., at the optimal temperature of production of the enzymes; however, the low level of activity at the highest temperature could be due to an additional post-transcriptional control.

Previous studies have indicated that oxygen-free radicals may cause damage to the periodontal tissues. This study compared the luminol-dependent chemiluminescence response (after stimulation with either opsonized zymosan or phorbol myristate acetate (PMA) of peripheral blood polymorphonuclear leukocytes (PMN) isolated from human subjects with a healthy periodontium (n = 7), gingivitis (n = 8), adult periodontitis (n = 8), or early-onset periodontitis (n = 17). These results were also compared with those obtained in a larger reference group which consists of 50 subjects without infection or inflammation, selected on the basis of laboratory investigations. An enhanced response was defined as being 2 standard deviations above the reference group mean; a reduced response was defined as being 2 standard deviations below this mean. Although PMN from patients with either gingivitis or periodontitis were often functionally activated (when compared to the PMN from the reference group), no significant differences could be found between the 4 groups, with regard to the chemiluminescence response means obtained in a basal state or after stimulation.

The polymorphonuclear neutrophil (PMN) appears to be an important cell in the protection of the host from pathogenic periodontal microorganisms and, despite some reports to the contrary, it is generally assumed that early-onset forms of periodontal disease (including both juvenile and rapidly progressing periodontitis) are associated with a defect in PMN chemotactic behaviour. The purpose of the present study was to examine the peripheral PMN chemotactic behaviour, using the under agarose method, in 4 groups, namely healthy periodontium group (n = 7), gingivitis group (n = 8), early-onset periodontitis group (n = 17) and adult periodontitis group (n = 8). PMN from early-onset periodontitis patients showed normal random and chemotactic locomotory behaviour when compared with those of PMN from subjects of the other groups. No statistically significant difference could be found among the 4 studied groups, with regard to spontaneous and oriented migration.

The psychotrophic strain Pseudomonas fluorescens MFO is known to express several enzymatic activities in milk, including extracellular proteolytic activity, optimally when cells are grown at 17.5 degrees C. In order to study the nature of the mechanisms controlling the production of the extracellular protease, we devised a defined medium in which this enzymatic activity was induced by an amino acid and small peptides. Regardless of the inducer, optimal proteolytic activity appeared at 17.5 degrees C. SDS-PAGE and isoelectrofocussing revealed a single protease produced by P. fluorescens MFO with all the inducers used and at all temperatures examined. The level of proteolytic activity correlated with the amount of enzyme in the supernatants.

Two transposon insertion mutants of Myxococcus xanthus altered in the secretion of protein as determined by the hydrolytic activities of several enzymes during vegetative growth were also unable to complete fruiting body formation and were severely impaired in sporulation. The insertions were located in the same part of the M. xanthus chromosome but were unlinked by transduction and therefore define two distinct loci, called excA and excB. Since both Exc +/- mutants were able to rescue development of an asgB mutation, they do not belong to the Asg- group, despite of the fact that asg mutants are also Exc +/-. Our results sustain the hypothesis of a possible relationship between protein secretion during vegetative growth and development or sporulation.

We describe here an extracellular proteolytic activity secreted during both growth and submerged development by Myxococcus xanthus DK1622. This activity yields the clotting of kappa-casein at pH 6 and is inhibited by specific inhibitors of aspartic proteases. Secretion of this milk-clotting proteolytic activity (of Mcp) is time regulated during the developmental cycle, with a large increase near 9 h poststarvation, but its production does not require cell-cell contact. The lack of secretion of this activity by several developmental mutants in submerged development conditions shows that Mcp production is developmentally regulated.

In accordance with previous results, the activity of extracellular proteases from Pseudomonas fluorescens MF0 is maximal at a growth temperature of 17.5 degrees C, well below the optimal growth temperature. In addition, the activities of three periplasmic phosphatases display the same growth temperature optimum. Chemostat experiments have shown that it is the growth temperature itself and not the value of the growth rate that regulates these activities. In contrast, a foreign periplasmic phosphatase, expressed under the control of its own promoter, displays a different sensitivity toward temperature. We conclude that in the psychrotrophic strain P. fluorescens MF0, growth temperature exerts a specific control upon the activity of certain enzymes. The critical temperature (17.5 degrees C) is within the range of normal growth, suggesting that this control is probably different from a cold shock or heat shock response.

The inducibility of two promoter systems, one heterologous and one homologous, has been assessed in the Gram-negative bacterium Myxococcus xanthus. The heterologous system involved the hybrid tac promoter and the presence of lacIq, the lac repressor from Escherichia coli. This system is inducible in its natural host with isopropyl-beta-D-thiogalactopyranoside (IPTG). The homologous promoter system involves the light-inducible carQRS promoter, which is normally involved in the expression of the regulators of the light-inducible light-protective carotenoid synthesis regulon in M. xanthus. In each case, promoter activity and strength was assayed using the E. coli gene lacZ. In our constructs, which were present in a single copy in the M. xanthus chromosome, the carQRS promoter yielded at least a 47-fold increase in beta-galactosidase production upon light induction, whilst IPTG increased by 8-fold the amount of enzyme produced under the control of the ptac-lacIq system. Regulation by the latter was significantly higher than that obtained with the unmodified lacZ promoter.

The site-specific recombination mechanism through which the plasmid RP4 has been previously shown to integrate into the chromosome of Myxococcus xanthus has been investigated further. Once integrated in one of the numerous chromosomal sites from two different strains, through a precise site on the plasmid, the latter can be excised either precisely or after a definite 14.5-kb deletion. In some cases, the integration is followed by different DNA rearrangements that yield a higher rate of excision and integration. A model for the site-specific integration and excision of the plasmid is proposed.

The immune response is now proved to be of great importance in the control of periodontal diseases. The predominant role of T lymphocytes in the mechanisms of specific immunity is admitted and is related to the functions of effectors T cells and T-helper cells, controlling the response of macrophages and the antibody production. The relations between the evolution of the disease and the tissular T/B and T4/T8 ratio and the lymphocyte function tests are discussed.