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Biomedical subjects

D De Clercq

Publications and source records attributed to D De Clercq.

At least 19 recordsLinked to original sources
PubMed2003

Percutaneous puncture technique for treating persistent retropharyngeal lymph node infections in seven horses.

Between 1999 and 2001, seven horses with fever, dysphagia and a history of chronic upper respiratory tract infection lasting between three weeks and three months were examined. They had been treated unsuccessfully with a variety of antibiotics for three to four weeks. A deep abscess in a retropharyngeal lymph node was diagnosed in each case by clinical examination, endoscopy and echographic examination of the retropharyngeal region. The infected retropharyngeal lymph node of each horse was punctured with a spinal needle under ultrasound guidance. Pus was aspirated from four of the horses, and their abscesses were then rinsed with 0.9 per cent saline solution, and antibiotics (sodium ceftiofur or penicillin) were injected. In the other three horses the pus was too viscous to be aspirated, and the enlarged lymph node was opened along the tract of the needle and rinsed with chlorhexidine. All the horses were treated with penicillin for two weeks and in six of them the clinical signs gradually disappeared. The other horse continued to show fever and the penicillin treatment was continued for another 10 days, after which the signs gradually disappeared over a period of two months.

Animals↗
PubMed2003

Human water contacts patterns in Schistosoma mansoni epidemic foci in northern Senegal change according to age, sex and place of residence, but are not related to intensity of infection.

In an epidemic focus in northern Senegal, adults had lower intensities of infection than adolescents, a phenomenon that could not be attributed to immunity acquired over the previous 10-15 years of exposure to the parasite because all age groups had had the same number of years' experience of the worm. This article considers whether this pattern could have been because of higher levels of exposure to the parasite in younger age groups. Personal contact with infected water was recorded using a questionnaire in Schistosoma mansoni foci not more than 3 years old and in another, 10-year-old focus. Many aspects of contact (e.g. frequency, duration or time of day of contact) may contribute to the number of encounters with infective cercariae (true exposure), so various assumptions regarding the relationship between water contact and true exposure were tested resulting in a range of exposure indices. People reported a mean of 4.4 separate contacts, and spent a median of 57 min per day in water. Patterns of water contact differed depending on the exposure index used, e.g. considering duration, males spent a longer time in water than females (P < 0.001). But using frequency, females had more contacts with water than males in most villages (P < 0.001). Generally, exposure levels dropped as people become aged (P < 0.001) and residents of the older focus were more exposed than residents of other foci (P < 0.002). Intensity of (re)infection was not related to exposure either alone or in models incorporating age, sex and/or village irrespective of the index used. There is therefore evidence that age, sex and place of residence determine exposure but none to suggest that exposure had an influence on the relationship between these factors and intensity of infection. We propose therefore that in this population other factors have principal importance in determining intensity of infection.

Adolescent↗
PubMed2002

Efficacy of artesunate and praziquantel in Schistosoma haematobium infected schoolchildren.

Praziquantel is the current mainstay for morbidity control of schistosomiasis. Artemisinin and its derivatives, widely used for the treatment of malaria, also display antischistosomal properties. The present study is an effort to assess the therapeutic efficacy of artesunate, an artemisinin derivative, in Schistosoma haematobium infections in a human population. The efficacy of artesunate and praziquantel were comparatively studied in primary schoolchildren from two villages, Lampsar (n=180) and Makhana (n=108), located along the Lampsar river in the delta of the Senegal River Basin in Northern Senegal (West Africa). In each village, half of the infected children were treated with a single oral dose of 40 mg/kg praziquantel and half with artesunate following the recommended malaria monotherapy regimen. For both drugs, cure and egg count reduction rates were, without apparent explanation, higher in Makhana than in Lampsar. In both villages, high and nearly comparable egg count reduction rates were obtained with both drugs at each follow-up after treatment (5, 12 and 24 weeks) in the heavy infected group of children (>50 eggs/10 ml of urine). No major adverse effects were observed. The results demonstrate that artesunate is effective against S. haematobium, but the results obtained with praziquantel were consistently better.

Adolescent↗
PubMed2002

Treadmill exercise negatively affects visual contribution to static postural stability.

This study was undertaken to explore the nature of impaired postural stability following physical exercise. Nine healthy subjects (aged 24 +/- 3 years) were subjected to 30 min of treadmill walking or running on two separate occasions. Walking and running speeds (1.9 to 2.2 m/s) were chosen to induce equal energy expenditure. During treadmill exercise, kinematic analysis of head movement was performed. Prior to and immediately following exercise, postural sway was evaluated as mean velocity of centre of pressure (VCOP), measured on a force plate during 30 s quiet stance with eyes open or eyes closed. The results indicate that exercise increased two-dimensional postural sway by 9 - 19 % in eyes open, but not in the eyes closed condition. The deteriorating effect of exercise was both evident in the sagittal and in the frontal plane, although the effect on the former was slightly more transient. Post-exercise sway values were significantly higher after running than after walking. Kinematic analysis of head movement confirmed larger vertical displacement and acceleration pattern in running compared to walking. It is concluded that exercise of moderate intensity deteriorates visual contribution to postural stability. The effect is evident as an initial destabilisation in the sagittal direction and a less transient loss of latero-lateral stability. Running tends to disturb postural stability more than walking, possibly due to more excessive head movement and disturbance of vestibular and visual information centres.

Adult↗
PubMed2001

Back care education in elementary school: a pilot study investigating the complementary role of the class teacher.

This study investigated the efficacy of guidelines for a motivated class teacher to enhance the application of back care principles, taught by a physical therapist, in fifth-grade elementary schoolchildren. Testing consisted of a practical test before and a practical test, knowledge test and candid camera evaluation 11 weeks after the program. Three groups were compared: an intervention group of 38 pupils, with extra guidelines for the teacher, an intervention group of 48 pupils, without extra guidelines and 34 controls. The intervention plus guidelines group, compared to the intervention group without extra teacher guidelines, obtained significantly higher posttest-pretest gain scores for five of the seven practical test items and scored significantly higher for seven of the nine items of the candid camera evaluation. Knowledge test scores did not differ significantly between the two intervention groups. Study results indicate that guidelines to a motivated class teacher improve efficacy of back care education in elementary schoolchildren.

Activities of Daily Living↗
PubMed2001

Necessary precautions in measuring correct vertical jumping height by means of force plate measurements.

The present study was designed to investigate the determination of vertical jumping height by means of force plate measurements. Four different sources of error influence this determination: the measurement of body mass, the determination of take off, the integration frequency, and the assessment of the initial conditions influencing the determination of the start of the movement. A theoretical model was utilized to simulate the vertical ground reaction forces in vertical jumping and to compare the outcome of analytical and numerical double integration of the vertical acceleration of the body centre of mass. A high integration frequency and an optimizing loop for body mass determination were found to be important and should be taken into account when determining jumping height parameters.

Acceleration↗
PubMed2001

Generalization of back education principles by elementary school children: evaluation with a practical test and a candid camera observation.

UNLABELLED: The efficacy of back education in elementary school children was shown using a practical test. Similar results in a candid camera evaluation were questioned. The purposes of this study were (i) to explore the relationship between the results of a practical test and the results of a candid camera procedure when evaluating back education principles, and (ii) to investigate whether in a candid camera procedure scores are still better in pupils who followed a back education programme than in controls. A candid camera evaluation followed by a practical test was performed in 71 pupils who had participated in a back education programme and 60 controls. Correlations between the two evaluation methods were significant but weak for 5 of the 9 test items in the intervention group (Rs 0.26-0.46) and for 7 test items in the control group (Rs 0.38-0.58). The difference in sum scores between the evaluation methods was significantly higher in the intervention group than in the control group (p < 0.001). The intervention group scored higher than the control group for 8 practical test items and 7 candid evaluation items. CONCLUSION: The study results question the use of a practical test for the individual evaluation of back education principles but show the usefulness of a practical test to study programme efficacy. As some principles seem to have become a habit, while for the implementation of others the pupils need external stimuli, the effects of more specific guidelines for parents and teachers to generalize back education principles require further study.

Back Pain↗
PubMed2001

Studies on the biology of schistosomiasis with emphasis on the Senegal river basin.

The construction of the Diama dam on the Senegal river, the Manantali dam on the Bafing river, Mali and the ensuing ecological changes have led to a massive outbreak of Schistosoma mansoni in Northern Senegal, associated with high intensity of infections, due to intense transmission, and the creation of new foci of S. haematobium. Data on the vectorial capacity of Biomphalaria pfeifferi from Ndombo, near Richard Toll, Senegal are presented with sympatric and allopatric (Cameroon) S. mansoni. Comparisons are made on infectivity, cercarial production, chronobiology of cercarial emergence and longevity of infected snails. Recent data on the intermediate host specificity of different isolates of S. haematobium from the Lower and Middle Valley of the Senegal river basin (SRB) demonstrate the existence of at least two strains of S. haematobium. The role of Bulinus truncatus in the transmission of S. haematobium in the Lower and Middle Valleys of the SRB is reviewed. Both S. haematobium and S. mansoni are transmitted in the same foci in some areas of the SRB.

Animals↗
PubMed2000

Biomechanical analysis of the stance phase during barefoot and shod running.

This study investigated spatio-temporal variables, ground reaction forces and sagittal and frontal plane kinematics during the stance phase of nine trained subjects running barefoot and shod at three different velocities (3.5, 4.5, 5.5 m s(-1)). Differences between conditions were detected with the general linear method (factorial model). Barefoot running is characterized by a significantly larger external loading rate than the shod condition. The flatter foot placement at touchdown is prepared in free flight, implying an actively induced adaptation strategy. In the barefoot condition, plantar pressure measurements reveal a flatter foot placement to correlate with lower peak heel pressures. Therefore, it is assumed that runners adopt this different touchdown geometry in barefoot running in an attempt to limit the local pressure underneath the heel. A significantly higher leg stiffness during the stance phase was found for the barefoot condition. The sagittal kinematic adaptations between conditions were found in the same way for all subjects and at the three running velocities. However, large individual variations were observed between the runners for the rearfoot kinematics.

Adolescent↗
PubMed2000

The epidemiology of human hookworm infections in the southern region of Mali.

Two surveys of hookworm (Necator americanus) infections, conducted three years apart (December 1994 and January 1998) in a village in the Sikasso region of Mali, revealed that overall prevalence of infection was 68.7% and 53%, respectively. In both years there was a highly significant difference between the sexes in the prevalence and abundance of infection, with male subjects carrying heavier infections than females. Both prevalence and abundance of infection increased with age, although in 1998 there was a strong interaction between sex and age, arising from the declining egg counts among 16-20-year-old females and the continuing increase among males, reinforced by the subsequent reduction among the older males (> or = 61 years) and concomitant increase among females. After controlling for the effects of age, sex and their interaction, a highly significant positive relationship was detected between faecal egg counts of individuals who were examined in both 1994 and 1998 (n = 134), indicating predisposition to infection. This relationship remained significant in each of 4 age classes spanning 7-79 years. The members of some family compounds were shown to carry heavier infections than expected whilst others were less infected, suggesting compound-related clustering of hookworm infections. The use of footwear increased with age but there was no significant relationship between the extent of use of footwear and the abundance of hookworm infection. Eyesight deteriorated with age and impaired vision was particularly prominent among the older sectors of the community, a legacy from the time when onchocerciasis was widely prevalent in the region. Although men with partially damaged eyes carried lower infections than expected for their age, no overall significant relationship was found between quality of vision and hookworm infections. These results are discussed in relation to hookworm epidemiology in general and in Mali in particular.

Adolescent↗
PubMed2000

What is the effect of combining artesunate and praziquantel in the treatment of Schistosoma mansoni infections?

A group of 110 individuals with Schistosoma mansoni infection was investigated. Patients were allocated to one of three treatment groups and given artesunate or praziquantel alone or both in combination. Combined artesunate-praziquantel significantly increased the number of individuals cured at 5 weeks post-treatment, but at 12 weeks was only better than artesunate alone and at 24 weeks there was no statistically significant difference between the three groups. Egg count reduction rate was similar to the rate obtained with praziquantel used alone.

Adolescent↗
PubMed2000

Effects of back care education in elementary schoolchildren.

UNLABELLED: The purpose of this study was to investigate the effects of a back care education programme, consisting of six sessions of 1 h each, in fourth- and fifth-grade elementary schoolchildren. Testing consisted of a practical performance and a back care knowledge test. Forty-two subjects and 36 controls performed a pre-test and were tested within 1 wk after the programme. To monitor effects and follow-up effects on a larger sample, 82 different pupils were tested within 1 wk after the programme and 116 other children 3 mo after. Both larger samples were compared with one group of 129 controls. Interrater reliability for the test items of the practical assessment was high; intraclass correlation coefficients varied from 0.785 to 0.980. In the pre/post design study, interaction between time and condition was significant for the sum score of the practical assessment and for the knowledge test (p < 0.001), with higher scores for the intervention group (15% improvement for the knowledge test score, 31.6% for the practical sum score). Significantly higher sum scores for the knowledge test and for all practical assessment items were found in the intervention groups, tested within 1 wk and 3 mo after the programme, in comparison with the control group (p < 0.001). CONCLUSION: The effectiveness of a primary educational prevention programme on back care principles was demonstrated in this study. Effectiveness, long-term outcomes and behavioural changes need further evaluation to optimize back care prevention programmes for elementary schoolchildren.

Back Pain↗
PubMed1999

The epidemiology of a recent focus of mixed Schistosoma haematobium and Schistosoma mansoni infections around the 'Lac de Guiers' in the Senegal River Basin, Senegal.

A village with mixed Schistosoma mansoni and S. haematobium infections (probably in a early endemic phase) was identified around the Lac de Guiers in the Senegal River Basin. In documenting the epidemiology of both schistosomes, we focused on prevalence and intensity of infection, transmission patterns and the impact of treatment. S. mansoni prevalences (near 100%) and egg counts (overall geometric mean eggs per gram of faeces (epg) of 589 were high in all age groups, with 35% of individuals excreting > 1000 epg, and showing a slow decline in egg output only after the age of 30 years. The overall prevalence (28%) and egg counts (2% > 50 eggs/10 ml) of S. haematobium were low, with mean counts of 6.3 eggs/10 ml. Maximal mean S. mansoni egg counts were found in 5-9 year-old boys and in 15-19 year-old girls; S. haematobium maximal counts in 1-4 year-old boys and in girls aged 5-9. Extremely high Biomphalaria pfeifferi infection ratios were recorded over the whole year. Following a single treatment, re-infection was rapid with prevalences and mean egg counts of both Schistosoma species reaching pretreatment levels within 7 months.

Adolescent↗
PubMed1998

The influence of exercise and dehydration on postural stability.

The aim of this study was to investigate the effects of exercise-induced and thermal dehydration on postural balance. Eight male subjects cycled for 2 h at a power output equal to 57-63% VO2max on two different occasions: once without drinking (NF) and once with intake of 1.9 l of a carbohydrate-electrolyte solution (FR). Before and after the exercise test, the velocity of the centre of pressure (COP) excursion was measured on a force platform during 30-s bipedal standing in normal position, feet side by side, and tandem position, feet heel to toe. On another occasion, eight subjects underwent seven consecutive sauna sessions (85 degrees C, 50% rh) of 15 min duration with no fluid replacement (S) to induce thermal dehydration. Mean fluid loss was 2.7 (+/- 0.4)%, 0.5 (+/- 0.5)% and 3.0 (+/- 0.6)% of body mass after NF, FR and S, respectively. Mean velocity of COP excursion after the exercise test was significantly higher in the NF than in the FR trial (p < 0.05). Postural stability was not influenced by S. In conclusion, prolonged exercise without fluid ingestion seems to negatively affect postural stability, whereas no effect is observed after exercise with fluid replacement or after thermal dehydration.

Adult↗
PubMed1997

Assessment of cure by detection of circulating antigens in serum and urine, following schistosomiasis mass treatment in two villages of the Office du Niger, Mali.

Eight weeks after mass chemotherapy with 40 mg/kg praziquantel in two villages in Office du Niger (an irrigation area in Mali, endemic for both Schistosoma haematobium and Schistosoma mansoni) the circulating anodic (CAA) and cathodic (CCA) antigen detection assays were carried out on serum and urine samples. Both prior and post treatment highest prevalence was measured with the urine-CCA assay. Cure rates determined by antigen detection were almost half that of the egg counting methods. It was shown that the reduction in intensity should be preferentially assessed by the serum-CAA assay. Compared with egg detection, a single antigen detection assay gave a much better assessment of the impact of chemotherapy.

Animals↗
PubMed1997

Circulating anodic and cathodic antigen in serum and urine of mixed Schistosoma haematobium and S. mansoni infections in Office du Niger, Mali.

In Office du Niger, an area endemic for both Schistosoma haematobium and S. mansoni in Mali, circulating anodic (CAA) and cathodic (CCA) antigen detection assays were performed on pretreatment serum and urine samples from two villages, Rigandé and Siguivoucé, and compared with egg counting methods. The highest prevalence was obtained with the urine-CCA assay which also had the highest sensitivity to S. haematobium, S. mansoni or mixed infection. A single urine-CCA assay was as sensitive as repeated egg counts (one stool+two urine examinations per individual). When the different assays were tested in parallel, several combinations including assays on serum were found to be highly sensitive. As urine sampling is widely accepted, urine assays will be used for further monitoring these villages one and two years after chemotherapy.

Animals↗
PubMed1997

Failure of mebendazole in treatment of human hookworm infections in the southern region of Mali.

Preliminary studies indicated that single-dose (500 mg) mebendazole gave disappointing results in the treatment of hookworm infections (Necator americanus) in Mali. A placebo-controlled, randomized trial conducted with the participation of 103 infected subjects (background hookworm prevalence > 50%) confirmed that mebendazole (Vermox) did not reduce parasite burdens significantly, as assessed through fecal egg counts. In contrast, a group of subjects treated with pyrantel (Combantrin) experienced a significant reduction in fecal worm egg counts (overall, both sexes combined showed a 75% reduction). Male subjects carried significantly more intense infections compared with females, but there was no gender difference in response to treatment. A standard egg hatch assay showed that N. americanus from our subjects in Mali was more resistant to benzimidazoles compared with a laboratory-maintained strain that had not been exposed to anthelmintics in more than 100 generations (50% effective dose = 0.12 and 0.07 microg/ml of thiabendazole, respectively), suggesting that, among other possibilities, the development of resistance to the benzimidazoles by N. americanus may have contributed to the drug failure. Whatever the underlying explanation, our results indicate that single-dose treatment with mebendazole is an ineffective treatment for hookworm infections and despite its relatively cheap cost and wide availability, mebendazole should not be considered a drug of choice in the mass treatment of hookworm infections in this region of Mali.

Adolescent↗