501 research outputs found
The effect of irrigated urban agriculture on malaria, schistosomiasis and soil-transmitted helminthiasis in different settings of Côte d'Ivoire
No full textMalaria is responsible for more than one million deaths every year, mainly children under the age of five years living in sub-Saharan Africa. At least one billion people harbor one or several of the three main soil-transmitted helminths, namely Ascaris lumbricoides, hookworms and Trichuris trichiura, and about 207 million people are infected with schistosomes. An estimated 70,000 people die each year from amoebiasis, caused by Entamoeba histolytica. Giardiasis, caused by Giardia duodenalis, is responsible for 2.8 million annual infections. Poor rural and urban communities in developing countries bear the highest burden of the above-mentioned diseases. Their causes are multifactorial including lack of access to clean water, improved sanitation and health services, as well as inadequate treatment, protection and prevention. The highest rates of urbanization currently occur in the less developed regions of Africa and Asia, and it is predicted that the majority of the population will be living in small and medium urban centers in the near future. The maintenance of traditional livelihoods, including agriculture, is a typical feature in urban settings across Africa, especially in small towns where population densities and land pressure are lower than in big cities. Urban agriculture contributes to food security and livelihood opportunities for poor urban dwellers. However, the adaptation of disease vectors and intermediate hosts to urban ecosystems has been observed, which might further enhance the negative effects associated with persistent rural lifestyles. For example, the creation of malaria vector breeding sites and contact with contaminated water and soil in areas of irrigated agriculture may increase the transmission of vector-borne, water-related and soil-transmitted parasitic diseases. This PhD focused on the interface of agriculture and human health in two different urban settings of Côte d’Ivoire. The overarching goal was to contribute to a better understanding of the effects of irrigated urban agriculture on the transmission of malaria, schistosomiasis, soil-transmitted helminthiasis and intestinal protozoan infections. The research entailed a considerable amount of fieldwork, carried out between April 2004 and July 2005. In a first step, six zones of irrigated agricultural land use were identified both in Abidjan, the economic capital of Côte d’Ivoire (3.3 million inhabitants), and in the mediumsized town of Man (115,000 inhabitants) in the western part of the country. Next, two standardized mosquito breeding site assessments were conducted in these agricultural zones in the rainy season (September 2004) and in the dry season (February 2005). In each urban setting, a minimum of 120 farming households and additionally 30 non-farming households were randomly selected. Geographic coordinates of houses and the main agricultural plots were recorded. Name, age and sex of all household members were registered. In October
2004, interviews on agricultural land use, farming practices and water storage were
conducted with the heads of the farming households. In a cross-sectional survey done in
May/June 2005, questionnaires were administered to all households to assess the socioeconomic
status, sanitary facilities and common water contact patterns. From each study
participant, a finger prick blood sample and a stool sample were collected. Thick and thin
blood films were stained with Giemsa and examined for Plasmodium spp. under a light
microscopy. The stool samples were prepared based on the Kato-Katz technique and eggs of
Schistosoma mansoni, A. lumbricoides, hookworm and T. trichiura were recorded separately.
Cysts or trophozoites of intestinal protozoa, including Entamoeba histolytica/E. dispar and G.
duodenalis were identified using an ether-formalin concentration method. Risk factors were
identified by fitting multivariate non-random and random effects Bayesian regression models
integrating spatial correlation of infection.
Agricultural land use in Abidjan was characterized by market gardens on lagoon shores
and high-yield vegetable production. The vegetable production areas in Abidjan developed as
a consequence of land access difficulties in unexploited public and private areas near poor
settlements, mainly at lagoon shores. In Man, farming was family- and subsistence-based.
Predominant agricultural activities were traditional irrigated rice farming and vegetable
production in lowlands and along the Kô River.
The typical demographic and socio-economic profile of a vegetable producer in
Abidjan is that he is an immigrant from Burkina Faso, illiterate and lacking a professional
agricultural training. Malaria and intestinal parasitic infections were most prevalent among
the final study cohort of 370 farmers and family members from 121 farming households. We
found overall prevalences of T. trichiura, P. falciparum and hookworm of 42.6%, 24.3% and
17.3%, respectively. The parasites were heterogeneously distributed between the six market
garden zones. Prior health issues were suppressed by the farmers with the daily livelihood
struggle and reported symptoms due to intestinal parasitic infections were of less importance
when compared to malaria. In-depth focus group discussions revealed that the working
environment was discerned as unhealthy, and waste dumps and human defecation grounds
were perceived as main health risks. Farmer communities and their network are indicative for
the degree of social coherence and stability in a vegetable production area because these
zones are characterized by highly dynamic land use patterns.
In the town of Man, Anopheles larvae were present in 50.7% and 42.4% of 369 and 589
examined potential mosquito breeding sites in the rainy and in the dry season, respectively.
The most productive habitats were man-made, i.e. agricultural trenches, irrigation wells, and
flooded and recently transplanted rice plots. The overall prevalence of P. falciparum
infections in the final study cohort of 574 individuals from 112 farming households was
32.1%. Risk factors for P. falciparum in children <15 years of age included living in specific
agricultural zones (i.e. traditional irrigated rice plots, mixed crops and a large rice perimeter),
proximity to permanent man-made ponds and fish ponds, periodic stays overnight in farm
huts and low socio-economic status.
The final study cohort for S. mansoni and soil-transmitted helminthiasis comprised 586
individuals from 113 farming households. The overall prevalences of S. mansoni, hookworm,
E. histolytica/E. dispar and G. duodenalis were 51.4%, 24.7%, 20.2% and 6.3%, respectively.
Members from farming households harbored significantly more often an infection with
E. histolytica/E. dispar and G. duodenalis when compared to non-farming households.
Predictors for an S. mansoni infection included close proximity to the Kô River, contact with
irrigation wells and ponds on the agricultural plots and low educational attainment. Risk
factors for hookworm infection comprised living in agricultural zones of traditional
smallholder irrigated rice plots and a large rice perimeter, using water from domestic wells
and low socio-economic status. Infection prevalences of P. falciparum, S. mansoni and
hookworm were spatially highly heterogeneous between the agricultural zones and highest
infections occurred in a zone of a large rice perimeter. P. falciparum infection intensity and
hookworm infection prevalence were best explained by spatial random effect models. Spatial
correlation between farmers’ houses was not significant.
The findings of the present work illustrated a clear picture of the interconnections
between specific irrigated agricultural land use and agricultural activities, and malaria and
intestinal parasitic infections in different urban settings of Côte d’Ivoire. The outcomes lead
to an enhanced understanding of their epidemiology in local agro-ecological urban settings
and related contextual determinants (i.e. agricultural, behavioural, demographic, socioeconomic
and environmental factors) and allows the design of readily adapted prevention and
control interventions (e.g. tangible vector control strategies and prevention measures for
helminth infections) which actively involve farming communities in the subsequent
implementation and control management
Small animal bone healing models : standards, tips, and pitfalls results of a consensus meeting
No full textSmall animal fracture models have gained increasing interest in fracture healing studies. To achieve standardized and defined study conditions, various variables must be carefully controlled when designing fracture healing experiments in mice or rats. The strain, age and sex of the animals may influence the process of fracture healing. Furthermore, the choice of the fracture fixation technique depends on the questions addressed, whereby intra- and extramedullary implants as well as open and closed surgical approaches may be considered. During the last few years, a variety of different, highly sophisticated implants for fracture fixation in small animals have been developed. Rigid fixation with locking plates or external fixators results in predominantly intramembranous healing in both mice and rats. Locking plates, external fixators, intramedullary screws, the locking nail and the pin-clip device allow different degrees of stability resulting in various amounts of endochondral and intramembranous healing. The use of common pins that do not provide rotational and axial stability during fracture stabilization should be discouraged in the future. Analyses should include at least biomechanical and histological evaluations, even if the focus of the study is directed towards the elucidation of molecular mechanisms of fracture healing using the largely available spectrum of antibodies and gene-targeted animals to study molecular mechanisms of fracture healing. This review discusses distinct requirements for the experimental setups as well as the advantages and pitfalls of the different fixation techniques in rats and mice
Mechanisms of stress, energy homeostasis and insulin resistance in European adolescents: the HELENA study
No full textBACKGROUND AND AIMS: Stress is hypothesized to facilitate the development of obesity, whose the foundations are already set during childhood and adolescence. We investigated the relationship between the stress-system, selected mechanisms of energy homeostasis and insulin resistance (IR) in a sample of European adolescents. METHODS AND RESULTS: Within HELENA-CSS, 723 adolescents (12.5-17.5 years) from 10 European cities provided all the necessary data for this study. Fasting blood samples were collected for cortisol, leptin, insulin and glucose analysis. HOMA-IR was calculated from insulin and glucose concentrations. Adolescents' body fat (BF) %, age and duration of exclusive breastfeeding were assessed. For boys and girls separately, the relationship of cortisol with leptin, insulin, glucose and HOMA-IR was examined by computing Pearson correlation coefficients and Hierarchical Linear Models (HLMs), with 'city' as cluster unit, adjusting for age, BF% and duration of exclusive breastfeeding. In boys, Pearson correlation coefficients illustrated positive correlations of cortisol with insulin (r = 0.144; p = 0.013), glucose (r = 0.315; p < 0.001) and HOMA-IR (r = 0.180; p = 0.002), whilst in girls, this positive relationship was observed for leptin (r = 0.147; p = 0.002), insulin (r = 0.095; p = 0.050) and HOMA-IR (r = 0.099; p = 0.041), but not for glucose (r = 0.054; p = 0.265). Observed associations were independent of adolescents' age, BF% and duration of exclusive breastfeeding after computing HLMs. CONCLUSION: This study suggests that the stress-system is positively related to mechanisms of energy homeostasis and IR in European adolescents, and reveals a potential small gender difference in this relationship. The hypothesis that stress might facilitate the development of obesity during adolescence is supported.sponsorship: The HELENA Study has taken place with the financial support of the European Community Sixth RTD Framework Programme (Contract FOOD-CT-2005-007034). The content of this article reflects only the authors' views and the European Community is not liable for any use that may be made of the information contained therein. Additional support from the Spanish Ministry of Education (AGL2007-29784-E/ALI). This study was also financially supported by the Research Foundation - Flanders (FWO, grant no 1174609N01 to T. D. V) and by the Spanish Ministry of Health: Maternal, Child Health and Development Network (grant no RD08/0072 to L. A. M). The HELENA Study Group would like to acknowledge the participating adolescents and their parents for their voluntary contribution to the HELENA study. Many thanks to Anke Carstensen, Petra Pickert, Rosa Maria Torres and Ulrike Albers for their contribution to the laboratory work. (European Community|FOOD-CT-2005-007034, Spanish Ministry of Education|AGL2007-29784-E/ALI, Research Foundation - Flanders (FWO)|1174609N01, Spanish Ministry of Health: Maternal, Child Health and Development Network|RD08/0072)status: Publishe
Pulse wave propagation in a model human arterial network: assessment of 1-D visco-elastic simulations against in vitro measurements
No full textThe accuracy of the nonlinear one-dimensional (1-D) equations of pressure and flow wave propagation in Voigt-type visco-elastic arteries was tested against measurements in a well-defined experimental 1:1 replica of the 37 largest conduit arteries in the human systemic circulation. The parameters required by the numerical algorithm were directly measured in the in vitro setup and no data fitting was involved. The inclusion of wall visco-elasticity in the numerical model reduced the underdamped high-frequency oscillations obtained using a purely elastic tube law, especially in peripheral vessels, which was previously reported in this paper [Matthys et al., 2007. Pulse wave propagation in a model human arterial network: Assessment of 1-D numerical simulations against in vitro measurements. J. Biomech. 40, 3476–3486]. In comparison to the purely elastic model, visco-elasticity significantly reduced the average relative root-mean-square errors between numerical and experimental waveforms over the 70 locations measured in the in vitro model: from 3.0% to 2.5% (p<0.012) for pressure and from 15.7% to 10.8% (p<0.002) for the flow rate. In the frequency domain, average relative errors between numerical and experimental amplitudes from the 5th to the 20th harmonic decreased from 0.7% to 0.5% (p<0.107) for pressure and from 7.0% to 3.3% (p<10−6) for the flow rate. These results provide additional support for the use of 1-D reduced modelling to accurately simulate clinically relevant problems at a reasonable computational cost
Accuracy of the Kato-Katz, adhesive tape and FLOTAC techniques for helminth diagnosis among children in Kyrgyzstan.
No full textThe purpose of this study was to assess the accuracy of three copro-microscopic techniques for helminth diagnosis: Kato-Katz, adhesive tape and FLOTAC. A total of 163 children from a peri-urban municipality near Bishkek, Kyrgyzstan, participated and submitted multiple stool samples and adhesive tapes. Ninety children supplied at least two stool samples and two adhesive tapes. Three stool samples and three adhesive tapes were available from 71 and 64 children, respectively. From each stool sample, a single Kato-Katz thick smear was prepared and examined quantitatively. Additionally, the first stool sample was subjected to the FLOTAC technique and helminth eggs were counted. Adhesive tapes were checked for the presence of Enterobius vermicularis eggs. Using pooled results as a diagnostic 'gold' standard, the prevalence of Ascaris lumbricoides, E. vermicularis, Hymenolepis nana and Dicrocoelium dendriticum were 54.4%, 13.3%, 11.1% and 11.1%, respectively. Infection intensities were low. When compared to triplicate Kato-Katz, a single FLOTAC was more sensitive for the diagnosis of A. lumbricoides (89.5% versus 39.5%) and D. dendriticum (88.9% versus 33.3%), but less sensitive for H. nana (66.7% versus 88.9%). For E. vermicularis, three adhesive tapes showed much higher sensitivity than a single FLOTAC (92.9% versus 14.3%). FLOTAC yielded significantly higher faecal egg counts than Kato-Katz for A. lumbricoides and D. dendriticum. Overall results suggest that, although FLOTAC represents a promising technique for helminth diagnosis in Kyrgyzstan, the repeated adhesive tape test remains so far the method of choice for diagnosing E. vermicularis
Physical activity, sedentary time, and liver enzymes in adolescents: the HELENA study
No full textBACKGROUND: To examine the association between physical activity (PA) and liver enzyme levels in adolescents from nine European countries.
METHODS: The study comprised 718 adolescents (397 girls). PA was measured by accelerometry and expressed as total PA (counts/min), and time (min/d) engaged in moderate to vigorous intensity PA (MVPA). Time spent sedentary was also objectively measured. We measured serum levels of alanine aspartate aminostrasferase (AST), alanine aminostransferase (ALT), and gamma-glutamyltrasnferase (GGT), and the AST/ALT ratio was computed.
RESULTS: There was an association between MVPA and AST and AST/ALT (age, sex, and center-adjusted beta = 0.096, 95% confidence interval (CI): 0.016 to 0.118; and beta = 0.090, 95% CI: 0.006 to 0.112, respectively). Meeting the PA recommendations (60 min/d of MVPA) was significantly associated with higher AST and AST/ALT, which persisted after further adjusting for sedentary time and waist circumference. Sedentary time was not associated with any of the studied liver enzyme levels.
CONCLUSION: Meeting the current PA recommendations of 60 min/d of MVPA is associated with higher levels of AST and AST/ALT regardless of time spent sedentary as well as total and central body fat in European adolescents
A new model to analyze metaphyseal bone healing in mice
No full textBackground: Despite the increasing clinical problems with metaphyseal fractures, most experimental studies investigate the healing of diaphyseal fractures. Although the mouse would be the preferable species to study the molecular and genetic aspects of metaphyseal fracture healing, a murine model does not exist yet. Using a special locking plate system, we herein introduce a new model, which allows the analysis of metaphyseal bone healing in mice. Methods: In 24 CD-1 mice the distal metaphysis of the femur was osteotomized. After stabilization with the locking plate, bone repair was analyzed radiologically, biomechanically, and histologically after 2 (n = 12) and 5 wk (n = 12). Additionally, the stiffness of the bone-implant construct was tested biomechanically ex vivo. Results: The torsional stiffness of the bone-implant construct was low compared with nonfractured control femora (0.23 ± 0.1 Nmm/°versus 1.78 ± 0.15 Nmm/°, P < 0.05). The cause of failure was a pullout of the distal screw. At 2 wk after stabilization, radiological analysis showed that most bones were partly bridged. At 5 wk, all bones showed radiological union. Accordingly, biomechanical analyses revealed a significantly higher torsional stiffness after 5 wk compared with that after 2 wk. Successful healing was indicated by a torsional stiffness of 90% of the contralateral control femora. Histological analyses showed new woven bone bridging the osteotomy without external callus formation and in absence of any cartilaginous tissue, indicating intramembranous healing. Conclusion: With the model introduced herein we report, for the first time, successful metaphyseal bone repair in mice. The model may be used to obtain deeper insights into the molecular mechanisms of metaphyseal fracture healing. © 2012 Elsevier Inc. All rights reserved
Nutrition and lifestyle in European adolescents: the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study
No full textAdolescence is a critical period, because major physical and psychologic changes occur during a very short period of time. Changes in dietary habits may induce different types of nutritional disorders and are likely to track into adulthood. The aim of this review is to describe the key findings related to nutritional status in European adolescents participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. We performed a cross-sectional study in 3528 (1845 females) adolescents aged 12.5-17.5 y. Birth weight was negatively associated with abdominal fat mass in adolescents and serum leptin concentrations (in female adolescents), providing additional evidence for a programming effect of birth weight on energy homeostasis control. Breakfast consumption was associated with lower body fat content and healthier cardiovascular profile. Adolescents eat half of the recommended amount of fruit and vegetables and less than two-thirds of the recommended amount of milk and milk products but consume more meat and meat products, fats, and sweets than recommended. For beverage consumption, sugar-sweetened beverages, sweetened milk, low-fat milk, and fruit juice provided the highest amount of energy. Although the intakes of saturated fatty acids (FAs) and salt were high, the intake of polyunsaturated FAs was low. Adolescents spent, on average, 9 h/d of their waking time (66-71% and 70-73% of the registered time in boys and girls, respectively) in sedentary activities. Factors associated with adolescents' sedentary behavior included the following: 1) age; 2) media availability in the bedroom; 3) sleeping time; 4) breakfast consumption; and 5) season. Sedentary time was also associated with cardiovascular risk factors and bone mineral content. In European adolescents, deficient concentrations were identified for plasma folate (15%), vitamin D (15%), pyridoxal 5'-phosphate (5%), beta-carotene (25%), and vitamin E (5%). Scientists and public health authorities should raise awareness of the importance of a healthy and sustainable lifestyle as a foundation of the health of the European population, now and in the future
Thermoelastic determination of individual stresses in vicinity of a near-edge hole beneath a concentrated load
No full textCompulsory admissions of patients with mental disorders: state of the art on ethical and legislative aspects in 40 European countries
No full textWasserman D, Apter G, Baeken C, Bailey S, Balazs J, Bec C, Bienkowski P, Bobes J, Ortiz MFB, Brunn H, Bôke Ö, Camilleri N, Carpiniello B, Chihai J, Chkonia E, Courtet P, Cozman D, David M, Dom G, Esanu A, Falkai P, Flannery W, Gasparyan K, Gerlinger G, Gorwood P, Gudmundsson O, Hanon C, Heinz A, Dos Santos MJH, Hedlund A, Ismayilov F, Ismayilov N, Isometsä ET, Izakova L, Kleinberg A, Kurimay T, Reitan SK, Lecic-Tosevski D, Lehmets A, Lindberg N, Lundblad KA, Lynch G, Maddock C, Malt UF, Martin L, Martynikhin I, Maruta NO, Matthys F, Mazaliauskiene R, Mihajlovic G, Peles AM, Miklavic V, Mohr P, Ferrandis MM, Musalek M, Neznanov N, Ostorharics-Horvath G, Pajević I, Popova A, Pregelj P, Prinsen E, Rados C, Roig A, Kuzman MR, Samochowiec J, Sartorius N, Savenko Y, Skugarevsky O, Slodecki E, Soghoyan A, Stone DS, Taylor-East R, Terauds E, Tsopelas C, Tudose C, Tyano S, Vallon P, Van der Gaag RJ, Varandas P, Vavrusova L, Voloshyn P, Wancata J, Wise J, Zemishlany Z, Öncü F, Vahip
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