Pyrrolizidine alkaloids in honey: comparison of analytical methods

Pyrrolizidine alkaloids (PAs) are a structurally diverse group of toxicologically relevant secondary plant metabolites. Currently, two analytical methods are used to determine PA content in honey. To achieve reasonably high sensitivity and selectivity, mass spectrometry detection is demanded. One method is an HPLC-ESI-MS-MS approach, the other a sum parameter method utilising HRGC-EI-MS operated in the selected ion monitoring mode (SIM). To date, no fully validated or standardised method exists to measure the PA content in honey. To establish an LC-MS method, several hundred standard pollen analysis results of raw honey were analysed. Possible PA plants were identified and typical commercially available marker PA-N-oxides (PANOs). Three distinct honey sets were analysed with both methods. Set A consisted of pure Echium honey (61-80% Echium pollen). Echium is an attractive bee plant. It is quite common in all temperate zones worldwide and is one of the major reasons for PA contamination in honey. Although only echimidine/echimidine-N-oxide were available as reference for the LC-MS target approach, the results for both analytical techniques matched very well (n = 8; PA content ranging from 311 to 520 µg kg(-1)). The second batch (B) consisted of a set of randomly picked raw honeys, mostly originating from Eupatorium spp. (0-15%), another common PA plant, usually characterised by the occurrence of lycopsamine-type PA. Again, the results showed good consistency in terms of PA-positive samples and quantification results (n = 8; ranging from 0 to 625 µg kg(-1) retronecine equivalents). The last set (C) was obtained by consciously placing beehives in areas with a high abundance of Jacobaea vulgaris (ragwort) from the Veluwe region (the Netherlands). J. vulgaris increasingly invades countrysides in Central Europe, especially areas with reduced farming or sites with natural restorations. Honey from two seasons (2007 and 2008) was sampled. While only trace amounts of ragwort pollen were detected (0-6.3%), in some cases extremely high PA values were detected (n = 31; ranging from 0 to 13019 µg kg(-1), average = 1261 or 76 µg kg(-1) for GC-MS and LC-MS, respectively). Here the results showed significantly different quantification results. The GC-MS sum parameter showed in average higher values (on average differing by a factor 17). The main reason for the discrepancy is most likely the incomplete coverage of the J. vulgaris PA pattern. Major J. vulgaris PAs like jacobine-type PAs or erucifoline/acetylerucifoline were not available as reference compounds for the LC-MS target approach. Based on the direct comparison, both methods are considered from various perspectives and the respective individual strengths and weaknesses for each method are presented in detail.

Non-destructive and radiochemical determination of the neutron-induced production cross section of I-129 from Te and other neutron-induced cross sections on Te at 14.7 MeV

Cross sections of twelve neutron-induced reactions on tellurium at 14.7 MeV have been determined. Among them are the (n,2n) cross sections for the production of both 129Te isomers which were determined using gamma ray spectrometry. These reactions dominate the cosmogenic production of 129I in meteoroids and are therefore of special importance. In addition, the neutron-induced cross section on Te at 14.7 MeV for the production of 129I was also determined directly by accelerator mass spectrometry (AMS) after radiochemical separation. The results for the production cross section of 129I determined by the two methods agree within 5%.

New determination of the half-life of 205Bi

We report a new half-life value of 205Bi. During measurements of cross sections for the production of residual radionuclides in proton-induced reactions on lead and bismuth a discrepancy was recognised between the published half-life of 205Bi and our experimental results. In this work, the value for the half-life of 205Bi was determined to be (14.91±0.07) days, based on measurements on 33 irradiated lead samples.

Thin target cross sections for proton-induced formation of radionuclides from lead for E p≤71 MeV

Some new cross sections for proton-induced radionuclide formation from lead are presented. The results extend the previous measurements from about 70 MeV down to threshold energies. Emphasis was placed upon an improved method of γ-ray spectrum analysis which proved to be reliable and effective. The new results are compared with model calculations on the basis of an improved hybrid model of preequilibrium reactions which is able to reproduce the near target products very well. But for more than 6 emitted nucleons, experimental measurements are superior.

Monte Carlo determination of the characteristic limits in measurement of ionising radiation--fundamentals and numerics

It is shown how the decision threshold, the detection limit and the limits of a coverage interval - summarily called the characteristic limits - and, in addition, the best estimate and the associated standard uncertainty of a non-negative radiation measurand are to be calculated by using the Monte Carlo (MC) method in ionising-radiation measurements. The limits are mathematically defined by means of quantiles of the Bayesian distributions of the possible measurand values. The MC-induced uncertainties of the limits and typical problems connected with MC application are also treated. The paper can serve as a bridge between the ISO Guide to the Expression of Uncertainty in Measurement (GUM), Supplement 1 applying the MC method and ISO/FDIS 11929 (at present in preparation) dealing with the characteristic limits. As an illustration, a net count rate measurand, being the difference of a gross and a background count rate, is treated theoretically and numerically. More complex examples deal with the wipe test for surface contamination and with a linear multi-channel spectrum unfolding.

Adsorbed serum albumin is permissive to macrophage attachment to perfluorocarbon polymer surfaces in culture

Monocyte/macrophage adhesion to biomaterials, correlated with foreign body response, occurs through protein-mediated surface interactions. Albumin-selective perfluorocarbon (FC) biomaterials are generally poorly cell-conducive because of insufficient receptor-mediated surface interactions, but macrophages bind to albumin-coated substrates and also preferentially to highly hydrophobic fluorinated surfaces. Bone marrow macrophages (BMMO) and IC-21, RAW 264.7, and J774A.1 monocyte/macrophage cells were cultured on FC surfaces. Protein deposition onto two distinct FC surfaces from complex and single-component solutions was tracked using fluorescence and time-of-flight secondary ion mass spectrometry (ToF-SIMS) methods. Cell adhesion and growth on protein pretreated substrates were compared by light microscopy. Flow cytometry and integrin-directed antibody receptor blocking were used to assess integrins critical for monocyte/macrophage adhesion in vitro. Albumin predominantly adsorbs onto both FC surfaces from 10% serum. In cultures preadsorbed with albumin or serum-dilutions, BMMO responded similar to IC-21 at early time points. Compared with Teflon AF, plasma-polymerized FC was less permissive to extended cell proliferation. The beta(2) integrins play major roles in macrophage adhesion to FC surfaces: antibody blocking significantly disrupted cell adhesion. Albumin-mediated cell adhesion mechanisms to FC surfaces could not be clarified. Primary BMMO and secondary IC-21 macrophages behave similarly on FC surfaces, regardless of preadsorbed protein biasing, with respect to adhesion, cell morphology, motility, and proliferation.

Accumulation of (137)Cs in Brazilian soils and its transfer to plants under different climatic conditions

The spatial distribution and behaviour of the global fallout (137)Cs in the tropical, subtropical and equatorial soil-plant systems were investigated at several upland sites in Brazil selected according to their climate characteristics, and to the agricultural importance. To determine the (137)Cs deposition density, undisturbed soil profiles were taken from 23 environments situated between the latitudes of 02 degrees N and 30 degrees S. Sampling sites located along to the equator exhibited (137)Cs deposition densities with an average value of 219Bqm(-2). Extremely low deposition densities of 1.3Bqm(-2) were found in the Amazon region. In contrast, the southern part of Brazil, located between latitudes of 20 degrees S and 34 degrees S, exhibited considerably higher deposition densities ranging from 140Bqm(-2) to 1620Bqm(-2). To examine the (137)Cs soil-to-plant transfer in the Brazilian agricultural products, 29 mainly tropical plant species, and corresponding soil samples were collected at 43 sampling locations in nine federal states of Brazil. Values of the (137)Cs concentration factor plant/soil exhibited a large range from 0.020 (beans) to 6.2 (cassava). Samples of some plant species originated from different collecting areas showed different concentration factors. The (137)Cs content of some plants collected was not measurable due to a very low (137)Cs concentration level found in the upper layers of the incremental soils. Globally, the soil-to-plant transfer of (137)Cs can be described by a logarithmic normal distribution with a geometric mean of 0.3 and a geometric standard deviation of 3.9.

An extraordinary endocytobiont in Acanthamoeba sp. isolated from a patient with keratitis

In the present article, the detection and the development of a parasitic endocytobiont within host amoebae (Acanthamoeba sp.) recently isolated from the contact lens and the inflamed eye of a patient with keratitis is presented. An otherwise healthy 55-year-old female patient presented with keratitis in her inflamed left eye. She was a contact lens wearer and had no history of a corneal trauma. Acanthamoebae as well as other smaller free-living amoebae could be detected from the fluid of the contact lens storage cases by culture methods. A successful therapy could be provided consequently. Two of these Acanthamoeba strains showed intracellular aggregating organisms. Within 2 to 3 days, the host amoebae ruptured, and numerous microorganisms were released. We succeeded in detecting the mechanism of infection and intrusion of this organisms by using light and electron microscopy. Infection with this endocytobiont is a suitable model for studying the host-parasite relations while the parasites use their hosts as so-called Trojan horses (see Barker, Lambert, Brown, Infect Immun 61:3503-3510, 1992).

[A study of cardiovascular risk factors associated with atherosclerosis of thoracic aorta detected by transesophageal echocardiography in Vietnam]

This study was designed to assess the relationship between cardiovascular risk factors and the presence of atherosclerosis aortic lesions detected by transesophageal echocardiography (TEE), The purpose was to determine if risk factors observed in Vietnam are similar to those detected in industrial countries. Between 2000 and 2002, TEE was performed in a total of 181 patients with a mean age of 63.1 +/- 9.4 (range, 42 to 79). In male patients over the age of 60 years, smoking, hypertension, diabetes and dyslipidemia were associated with significantly greater thickness of the intima and significantly higher number of complex lesions at all levels of thoracic aorta. Presence of these risk factors was associated with a 4.2 to 7.9 fold higher likelihood of atherosclerotic plaque. Findings in our population of hospital patients in Vietnam indicate that, as in Western populations, age, male gender, smoking, arterial hypertension, diabetes, and hypercholesterolemia promote the appearance of plaques in the thoracic aorta. This study provides insight into the cardiovascular risk situation in a city in Southeastern Asia.

123I-IMT SPECT for evaluation of the response to radiation therapy in high grade gliomas: a feasibility study

Assessing response to radiation therapy in patients with high grade gliomas is needed upon making decisions toward further therapy strategies. Currently used standard imaging tools such as CT and MRI are not sensitive enough to detect early therapy effects. We prospectively investigated if single photon emission computed tomography (SPECT) using radiolabelled amino acid derivate (123)I-methyltyrosine (IMT) would be useful for this aim. 10 patients with histologically proven high grade gliomas, who were candidates for radiation therapy, were enrolled in this investigation. All patients were examined by IMT SPECT before radiation therapy and 4 weeks after the initiation of the hypofractionated application of 40 Gy. Patients were followed up for 39 months; the tumours to background ratios (T/B) for IMT under/before radiation therapy were correlated to survival times. Initially, SPECT depicted an abnormal intratumoural IMT uptake in all patients (mean T/B ratios 1.37-1.87). In four out of 10 patients, the mean T/B ratios decreased by more than 10% under radiation therapy. In six other patients, the BQ decreased by less than 10% or increased. There were no significant correlations between the degree of changes in T/B and survival (r = -0.1, p = 0.973). Serial IMT SPECT measurements allow detection of changes in amino acid accumulation in high-grade gliomas under radiation therapy. However, these changes seem to possess no prognostic value in respect to survival prediction.

Corrections of arterial input function for dynamic H215O PET to assess perfusion of pelvic tumours: arterial blood sampling versus image extraction

Assessment of perfusion with 15O-labelled water (H215O) requires measurement of the arterial input function (AIF). The arterial time activity curve (TAC) measured using the peripheral sampling scheme requires corrections for delay and dispersion. In this study, parametrizations with and without arterial spillover correction for fitting of the tissue curve are evaluated. Additionally, a completely noninvasive method for generation of the AIF from a dynamic positron emission tomography (PET) acquisition is applied to assess perfusion of pelvic tumours. This method uses a volume of interest (VOI) to extract the TAC from the femoral artery. The VOI TAC is corrected for spillover using a separate tissue TAC and for recovery by determining the recovery coefficient on a coregistered CT data set. The techniques were applied in five patients with pelvic tumours who underwent a total of 11 examinations. Delay and dispersion correction of the blood TAC without arterial spillover correction yielded in seven examinations solutions inconsistent with physiology. Correction of arterial spillover increased the fitting accuracy and yielded consistent results in all patients. Generation of an AIF from PET image data was investigated as an alternative to arterial blood sampling and was shown to have an intrinsic potential to determine the AIF noninvasively and reproducibly. The AIF extracted from a VOI in a dynamic PET scan was similar in shape to the blood AIF but yielded significantly higher tissue perfusion values (mean of 104.0 +/- 52.0%) and lower partition coefficients (-31.6 +/- 24.2%). The perfusion values and partition coefficients determined with the VOI technique have to be corrected in order to compare the results with those of studies using a blood AIF.

Bayesian decision threshold, detection limit and confidence limits in ionising-radiation measurement

Based on Bayesian statistics and the Bayesian theory of measurement uncertainty, characteristic limits such as the decision threshold, detection limit and limits of a confidence interval can be calculated taking into account all sources of uncertainty. This approach consists of the complete evaluation of a measurement according to the ISO Guide to the Expression of Uncertainty in Measurement (GUM) and the successive determination of the characteristic limits by using the standard uncertainty obtained from the evaluation. This procedure is elaborated here for several particular models of evaluation. It is, however, so general that it allows for a large variety of applications to similar measurements. It is proposed for the revision of those parts of DIN 25482 and ISO 11929 that are still based on conventional statistics and, therefore, do not allow to take completely into account all the components of measurement uncertainty in the calculation of the characteristic limits.

Do serological tissue turnover markers represent callus formation during fracture healing?

Serological parameters of bone and fibrous tissue turnover were demonstrated to monitor the course of fracture healing. The aim of this study was to evaluate the correlation between the serological parameter levels during fracture healing and callus development in a standardised ovine model of fracture healing. Two years old female sheep received a standardised 3 mm tibial bone defect stabilised by an external fixator. The serological levels of the C-terminal propeptide of procollagen type I (PICP), bone specific alkaline phosphatase (bALP), total alkaline phosphatase (tALP), osteocalcin, tartrate-resistant acid phosphatase (TRAP), calcium, phosphate and the N-terminal peptide of procollagen type III (PIIINP) were observed over a 9-week healing period. The course of fracture healing was monitored radiographically, and the callus composition was evaluated histologically at 2, 3, 6 and 9 weeks post-surgery. The serological results were compared with an untreated control group. Additionally, the maximum values during healing were compared with juvenile values to gauge the level of the serological response. The histological and radiographical results demonstrated callus formation without complications. All serological parameters showed broad inter-individual variations, and the response to the standardised fracture scenario was strongly individual. Maximum values during fracture healing did not reach the juvenile levels. The fractured as well as the control animals showed significant changes in the parameter levels. No correlations were observed between the histological course of healing and the course of bone formation markers whilst the TRAP level was reduced during bony callus formation. The PIIINP level increased when the amount of soft callus tissue decreased during healing. The observed bone formation markers were not suitable as general markers to detect the course of fracture healing, whilst PIIINP was able to reflect soft callus degradation.

[Correlation between rainfall and meningococcal meningitis in Niger]

The term "meningitis belt" was coined by Lapeyssonnie in 1963 to describe a zone in Africa where epidemic meningitis occurs sporadically during the dry season. The purpose of this study was to evaluate the relationship between the recorded rainfall and reported incidence of meningococcal meningitis in Niger from 1996 to 2002. A total of 58 277 cases of meningococcal meningitis were reported in Niger during the study period. The mean annual incidence was 82.2 per 10(5) inhabitants. Two epidemic years occurred during the study period, i.e., 1996 with 183 cases per 105 inhabitants and 2000 with 140 cases per 10(5). The incidence increased during the dry season and decreased at the beginning of the rainy season. Calculation of the correlation coefficient between rainfall and incidence of meningococcal meningitis showed a statistically significant negative correlation (r = -0.27; P = 0.01). Neisseria meningitidis sero-group A was predominant but strains of Neisseria meningitidis sero-group W135 have been found in specimens collected since 2002. Outbreaks of meningococcal meningitis epidemics are multi-factorial. Multivariate analysis of all factors would allow implementation of preventive measures earlier than the epidemic prediction strategy based on threshold rates proposed by the World Health Organization.

Iodine-129 in soils from Northern Ukraine and the retrospective dosimetry of the iodine-131 exposure after the Chernobyl accident

Forty-eight soil profiles down to a depth of 40 cm were taken in Russia and Ukraine in 1995 and 1997, respectively, in order to investigate the feasibility of retrospective dosimetry of the 131I exposure after the Chernobyl accident via the long-lived 129I. The sampling sites covered areas almost not affected by fallout from the Chernobyl accident such as Moscow/Russia and the Zhitomir district in Ukraine as well as the highly contaminated Korosten and Narodici districts in Ukraine. 129I was analyzed by radiochemical neutron activation analysis (RNAA) and accelerator mass spectrometry (AMS). 127I was measured for some profiles by RNAA or ion chromatography (IC). The results for 127I demonstrated large differences in the capabilities of the soils to store iodine over long time spans. The depth profiles of 129I and of 137Cs showed large differences in the migration behavior between the two nuclides but also for each nuclide among the different sampling sites. Though it cannot be quantified how much 129I and 137Cs was lost out of the soil columns into deeper depths, the inventories in the columns were taken as proxies for the total inventories. For 129I, these inventories were at least three orders of magnitude higher than a pre-nuclear value of 0.084+/-0.017 mBq m(-2) derived from a soil profile taken in 1939 in Lutovinovo/Russia. From the samples from Moscow and Zhitomir, a pre-Chernobyl 129I inventory of (44+/-24) mBq m(-2) was determined, limiting the feasibility of 129I retrospective dosimetry to areas where the 129I inventories exceed 100 mBq m(-2). Higher average 129I inventories in the Korosten and Narodici districts of 130 and 848 mBq m(-2), respectively, allowed determination of the 129I fallout due to the Chernobyl accident. Based on the total 129I inventories and on literature data for the atomic ratio of 129I/131I=13.6+/-2.8 for the Chernobyl emissions and on aggregated dose coefficients for 131I, the thyroid exposure due to 131I after the Chernobyl accident was estimated for the inhabitants of four villages in the Korosten and of three villages in the Narodici districts. The limitations and uncertainties of the 129I retrospective dosimetry are discussed.

Are bone turnover markers capable of predicting callus consolidation during bone healing?

The aim of this study was to determine the ability of the following bone turnover markers to monitor the course of callus consolidation during bone healing: Carboxy-terminal propeptide of procollagen type I (PICP), skeletal alkaline phosphatase (sALP), and amino-terminal propeptide of type III procollagen (PIlINP). Since interfragmentary movements have been proven to possess the ability to document the progression of bone healing in experimental studies, correlations between bone turnover markers and interfragmentary movements in vivo were investigated. Therefore, two different types of osteosyntheses representing different mechanical situations at the fracture site were compared in an ovine osteotomy model. Blood samples were taken preoperatively and postoperatively in weekly intervals over a nine-week healing period. At the same intervals, interfragmentary movements were measured in all sheep. After nine weeks, animals were sacrificed and the tibiae were evaluated both mechanically and histologically. Wide interindividual ranges were observed for all bone turnover markers. The systemic PICP level did not increase with callus consolidation. The bone-healing model seemed to influence the systemic level of PIIINP and sALP but no general correlation between bone turnover markers and interfragmentary movements could be detected. No differences between the different types of osteosyntheses and thus the different mechanical situations were observed. All analyzed markers failed as general predictors for the course of callus consolidation during bone healing.

[Measures of impact in epidemiology]

After establishing a link between an exposure factor and occurrence of a disease, it is necessary to measure the impact on public health. The etiologic fraction, preventable fraction, and number of cases avoided can be used to measure such impact. The purpose of this article is to present the calculation and interpretation of these indicators using an example taken from the journal of Médecine Tropicale.

[Communicating about risks to public health]

The goals of public health risk communication are to explain the risks, to inform a community without causing a crisis, to implicate the population in decision-making, and to improve dialogue between organizations and communities. Based on a document entitled "Communicating about risks to public health: pointers to good practice", the authors of this article review the main principles relevant to health risk communication and present a list of key points for effective management of this communication.

[Correlation measures in epidemiology]

When a significant correlation has been noted between the occurrence of a disease and exposure to a risk factor, it becomes necessary to measure the strength of the correlation. This can be done using either relative risk or odds ratio techniques depending on the type of study. The purpose of article this article is to present guidelines for calculation and interpretation of these indicators using examples taken from the Médecine Tropicale journal.

Endoparasite KC5/2 encloses large areas of sol-like cytoplasm within Acanthamoebae. Normal behavior or aberration?

In addition to the characteristic development of the rod-shaped or tube-like endocytobionts replicating within the sol-like cytoplasm of acanthamoebae which was published recently (Michel et al. 2003) we observed the strange behavior of the endoparasites described as follows. The material normally forming the characteristic cell walls of KC5/2 organisms was found to form a long array along the borderline between the granuloplasm and the central homogenous sol-like cytoplasm, so that about one third of the sol plasm had already been surrounded. We do not know whether this process belongs to the normal developmental repertoire of the endocytobiont that was interrupted by fixation for electron microscopy, or whether it is an aberrant behavior.

Increased production of interferon-gamma by Leishmania homologue of the mammalian receptor for activated C kinase-reactive CD4+ T cells among human blood mononuclear cells: an early marker of exposure to Leishmania?

A prospective study was undertaken to define early predictive immunological marker(s) of exposure to Leishmania in naïve subjects who have never been exposed to any Leishmania and who were also free of any cutaneous leishmaniasis lesions. These naïve subjects could have been exposed to Leishmania in a rain forest where Leishmania guyanensis and their natural vectors and mammalian host are cocirculating. The production of interferon (IFN)-gamma in response to the Leishmania homologue of the mammalian receptor for activated c kinase (LACK), a candidate for vaccine against leishmaniasis was analysed. At the end of their stay in the rain forest, LACK-specific CD8+ T cells were detected in subjects whose peripheral blood mononuclear cell (PBMC) produced IFN-gamma in response to soluble Leishmania antigens (SLA) and in those whose PBMC remained unresponsive to SLA. However, LACK-specific CD4+ T cells were detected only in PBMCs from individuals who became IFN-gamma responders to SLA. In subjects whose PBMC became positive to SLA, LACK-reactive CD4+ T cells producing high level of IFN-gamma were detectable before the SLA-reactive IFN-gamma producing CD4+ T cells, suggesting that the former readout assay could be used as an early predictive immunological marker of exposure to Leishmania in subjects who remained disease free.

Endocytobiont KC5/2 induces transformation into sol-like cytoplasm of its host Acanthamoeba sp. as substrate for its own development

New investigations of a novel, recently described, non-cultivable endocytobiont of Acanthamoeba sp. reveal at least three hitherto unobserved developmental stages which shed some light on the nature of this peculiar organism. The development of the endocytobiont is closely connected with conspicuous changes in the host amoeba, inducing the transformation from gel to sol-like cytoplasm which bulges like a balloon inside the host cell. Young and transitory developmental stages were found within the homogenous, sol-like cytoplasm. The infectious stages, with their voluminous cell wall and a conspicuous ostiole, could be observed within all parts of the cytoplasm with the exception of the nucleus. It is a remarkable adaptation for this parasite to be able to induce this gel-sol transformation in order to facilitate its own development. The fate of the heavily infected host amoebae is death by rupture or lysis after being overcrowded with parasites. As no structures could be observed within the endoparasites that were comparable to other bacteria, the real nature and taxonomic position of these peculiar organisms remain obscure.

[Statistical tests: value, principle and interpretation]

Comparison of data groups requires the use of statistical tests. This article utilizes an example taken from the Revue Médicine Tropicale to illustrate the value of statistical testing as well as an interpretation of the probability value "p" associated with test results.

Chemisorbed poly(propylene sulphide)-based copolymers resist biomolecular interactions

Alkanethiolates have been widely used as chemisorbates to modify gold surfaces, in spite of their relatively poor oxidative stability. We introduce gold-chemisorbing block copolymers bearing an anchoring block of poly(propylene sulphide) (PPS), selected in the expectation of greater stability. These materials offer a more robust approach to surface modification of gold. As an example, a triblock copolymer with poly(ethylene glycol) (PEG) was selected, with the goal of minimizing biological adsorption and adhesion. The copolymer PEG17-bl-PPS25-bl-PEG9 chemisorbed to form a dense monolayer of 226 +/- 26 ng cm(-2), approximately 2.2 nm thick. The copolymeric adlayer was much more stable to oxidation than commonly used alkanethiolates. Its presence greatly reduced protein adsorption (>95%), even after exposure to whole blood serum (>55 mg x ml(-1)), as well as cell adhesion over long culture durations (>97%). PPS-containing copolymers are an attractive alternative to alkanethiolates, and PEG-bl-PPS-bl-PEG presents a powerful example for use in biodiagnostic and bioanalytical devices.

Evaluation of radioactive exposure from 137Cs in contaminated areas of Northern Ukraine

The paper gives averages of 137Cs deposition densities in soils from three areas in Northern Ukraine measured 12 to 15 y following the Chernobyl accident: in an area near Narodici (75 km west of the Chernobyl nuclear power plant in the so-called zone II) heavily contaminated by the Chernobyl fall-out and in areas around Korosten and Zhitomir showing contamination levels to be much lower. The three areas exhibited very different 137Cs deposition densities of 2.2 MBq m(-2), 400 kBq m(-2), and 5 kBq m(-2), respectively. During a 1-y observation, measurements of the 137Cs transfer in the food chain to humans and 137Cs whole body contents dependent on the 137Cs daily intake were carried out under realistic conditions of the rural inhabitants who lived in settlements within zone II. Detailed investigations of components of the daily diet showed that the high 137Cs contamination levels found in soils of zone II do not affect in any way low 137Cs concentrations of all important agricultural products harvested and consumed by villagers. With regard to consumption habits of the population of zone II, mushrooms and wild berries were found to contribute more than 95% of the 137Cs daily intake to the 137Cs whole body content of about 12 kBq (with maximum values up to 760 kBq) measured in a group of inhabitants of zone II during a period from July 1998 to July 1999. The median of the annual dose of these inhabitants from external and internal exposures was 1.2 mSv y(-1) with a geometric standard deviation of 2.6. Excluding extreme habits, the geometric mean of the total exposure was 1.0 mSv y(-1) with a geometric standard deviation of 1.3.

[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.

[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.

[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.

[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.

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.

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.

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.

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.