Influence of design of dentist's chairs on body posture for dentists with different working experience.

BACKGROUND: Musculoskeletal disorders (MSD) are a common health problem among dentists. Dental treatment is mainly performed in a sitting position. The aim of the study was to quantify the effect of different ergonomic chairs on the sitting position. In addition, it was tested if the sitting position of experienced workers is different from a non-dental group. METHODS: A total of 59 (28 m/31f) subjects, divided into two dentist groups according to their work experience (students and dentists (9 m/11f) < 10 years, dentists (9 m/10f) ≥ 10 years) and a control group (10 m/10f) were measured. A three-dimensional back scanner captured the bare back of all subjects sitting on six dentist's chairs of different design. Initially, inter-group comparisons per chair, firstly in the habitual and secondly in the working postures, were carried out. Furthermore, inter-chair comparison was conducted for the habitual as well as for the working postures of all subjects and for each group. Finally, a comparison between the habitual sitting posture and the working posture for each respective chair (intra-chair comparison) was conducted (for all subjects and for each group). In addition, a subjective assessment of each chair was made. For the statistical analysis, non-parametric tests were conducted and the level of significance was set at 5%. RESULTS: When comparing the three subject groups, all chairs caused a more pronounced spinal kyphosis in experienced dentists. In both conditions (habitual and working postures), a symmetrical sitting position was assumed on each chair. The inter-chair comparisons showed no differences regarding the ergonomic design of the chairs. The significances found in the inter-chair comparisons were all within the measurementerror and could, therefore, be classified as clinically irrelevant. The intra-chair comparison (habitual sitting position vs. working sitting position) illustrated position-related changes in the sagittal, but not in the transverse, plane. These changes were only position-related (forward leaned working posture) and were not influenced by the ergonomic sitting design of the respective chair. There are no differences between the groups in the subjective assessment of each chair. CONCLUSIONS: Regardless of the group or the dental experience, the ergonomic design of the dentist's chair had only a marginal influence on the upper body posture in both the habitual and working sitting postures. Consequently, the focus of the dentist's chair, in order to minimize MSD, should concentrate on adopting a symmetrical sitting posture rather than on its ergonomic design.

The use of traditional and complementary medicine among patients with multiple sclerosis in Belgium.

Introduction. Conventional treatment of multiple sclerosis (MS) is often disappointing. As a result, some of these patients seek salvation in traditional and complementary medicine (T&CM). The aim of this study is to describe how many patients with MS use T&CM and what their motives and expectations are in doing so. Methods. Ninety-nine patients with diagnosed MS, attending the service of ambulatory revalidation of the National Clinic for Multiple Sclerosis in Melsbroek (Belgium) were included in February 2004 in this retrospective study. All patients had MS resulting in motoric or psychosocial symptoms. The disability was not quantified for this study. Participants were interviewed by means of a structured questionnaire on their current treatment of MS including T&CM. Results. In total 44% of the participants had experiences with T&CM. The most frequently used T&CM were homeopathy and acupuncture. Participants using conventional treatment were more satisfied with the support (p=0.006) and the treatment outcome (0.018) than T&CM users. The use of T&CM was not related to gender, education, living conditions, causal treatment such as disease modifying-therapy (DMT), grade of disability or subtype of the disease. Conclusion. Patients diagnosed with MS seek hope in T&CM such as homeopathy or acupuncture. The results of this study suggest that MS patients need more professional support in their personal search for alternative therapies. Key point. 50% of patients diagnosed with multiple sclerosis search relief in traditional and complementary medicine such as homeopathy or acupuncture. These patients often feel compelled to try every opportunity to heal, often stimulated or urged on by friends or relatives. Multiple sclerosis patients are more satisfied with their conventional treatment than with the traditional and complementary medicine.

How reliable are the risk estimates for X-ray examinations in forensic age estimations? A safety update.

Possible biological side effects of exposure to X-rays are stochastic effects such as carcinogenesis and genetic alterations. In recent years, a number of new studies have been published about the special cancer risk that children may suffer from diagnostic X-rays. Children and adolescents who constitute many of the probands in forensic age-estimation proceedings are considerably more sensitive to the carcinogenic risks of ionizing radiation than adults. Established doses for X-ray examinations in forensic age estimations vary from less than 0.1 microSv (left hand X-ray) up to more than 800 microSv (computed tomography). Computed tomography in children, as a relatively high-dose procedure, is of particular interest because the doses involved are near to the lower limit of the doses observed and analyzed in A-bombing survivor studies. From these studies, direct epidemiological data exist concerning the lifetime cancer risk. Since there is no medical indication for forensic age examinations, it should be stressed that only safe methods are generally acceptable. This paper reviews current knowledge on cancer risks associated with diagnostic radiation and aims to help forensic experts, dentists, and pediatricians evaluate the risk from radiation when using X-rays in age-estimation procedures.

The results of dietary advice on lipoprotein levels among patients attending for lipid-lowering drugs.

The aim of this study was to evaluate the changes in fasting lipoproteins levels before and after a dietary advice among the patients attending for a lipid-lowering treatment. In total 286 patients attending for reimbursement of a lipid-lowering drug were recorded at two regional health insurance offices. Lipid levels measured at least three months after the dietary advice were compared with those before the dietary advice. The mean age of the included patients was 61 years. The average fasting total cholesterol (TC) was 7.4 mmol/l before the dietary advice as well as after the dietary advice. Fasting TC did not decrease with the dietary advice in 51% of the included patients. In the logistic regression not one of the studied factors was correlated with a successful dietary advice. Half of the patients receiving lipid-lowering drugs in Belgium were not able to decrease their TC with dietary advice before the initiation of the treatment.

Primary prevention of coronary heart disease in general practice: a cross sectional population study.

The aim of this study was to assess the interventions by general practitioners on cardiovascular risk factors among persons without a history of cardiovascular disease attending for a cardiovascular check-up. All inhabitants of three Belgian towns aged between 45 and 64 years were invited for a cardiovascular check-up and blood test. Of all the attending persons without a history of cardiovascular disease (n = 898), 51% received at least one prescription, diet or health advice: 28% for hyperlipidaemia, 23% for physical activity, 22% for caloric intake, 9% for blood sugar, 5% for blood pressure and 4% for smoking. Interventions on lipoproteins, blood sugar and smoking habits were significantly more often proposed to persons with a medium or high cardiovascular risk compared to those at low cardiovascular risk. For persons at low cardiovascular risk, therapeutic lifestyle changes are often not advised, and isolated risk factors often remain untreated.

Effects of wortmannin and latrunculin A on slow endocytosis at the frog neuromuscular junction.

Phosphoinositides are key regulators of synaptic vesicle cycling and endocytic traffic; the actin cytoskeleton also seems to be involved in modulating these processes. We investigated the effects of perturbing phosphoinositide signalling and actin dynamics on vesicle cycling in frog motor nerve terminals, using fluorescence and electron microscopy, and electrophysiology. Antibody staining for beta-actin revealed that actin surrounds but does not overlap with synaptic vesicle clusters. Latrunculin A, which disrupts actin filaments by binding actin monomers, and wortmannin, an inhibitor of phosphatidyl inositol-3-kinase (PI3-kinase), each disrupted the pattern of presynaptic actin staining, but not vesicle clusters in resting terminals. Latrunculin A, but not wortmannin, also reduced vesicle mobilization and exocytosis. Both drugs inhibited the stimulation-induced uptake of the styryl dye FM1-43 and blocked vesicle reformation from internalized membrane objects after tetanic stimulation. These results are consistent with a role of PI3-kinase and the actin cytoskeleton in the slow pathway of vesicle endocytosis, used primarily by reserve pool vesicles.

An evaluation of pharmaceutical treatment of dyslipidaemia among patients without diagnosed atherosclerotic disease in Belgium.

The aim of this study was to assess the lipoprotein levels in patients without diagnosed atherosclerotic disease but treated with lipid-lowering drugs. During February and March 2002 all demands for continuation of reimbursement of lipid-lowering drugs were recorded at two regional offices of health insurance associations. A total of 1973 patients without diagnosed atherosclerotic disease were included (mean age 66 years). Mean total cholesterol (TC) was 5.39 mmol/l, high-density lipoprotein cholesterol (HDL-C) 1.50 mmol/l, low-density lipoprotein cholesterol (LDL-C) 3.16 mmol/l and triglycerides (TG) 1.59 mmol/l. Thirty-four per cent of the treated patients reached the TC target of 5.0 mmol/l or less. The LDL-C target level of 3.0 mmol/l or less was reached by 45% of the patients. Of the patients receiving a statin, 61% were not treated with the optimal doses. The treatment was adjusted in 15% of the patients who did not reach the combined endpoint.

An analysis of first authorizations for lipid-lowering drugs in Belgium.

INTRODUCTION: In Belgium lipid-lowering drugs are reimbursed in primary and secondary prevention when after a non-specified diet of at least three months total cholesterol (TC) remains higher than 250 mg/dl or triglycerides (TG) remain higher than 200 mg/dl. Low-density lipoprotein cholesterol (LDL-C) is only taken into account for the reimbursement of fibrates when it remains higher than 160 mg/dl in secondary prevention. The aim of this study was to evaluate the changes in fasting lipoproteins levels among patients who wait for the reimbursement of a lipid-lowering drug. Additionally, the parameters influencing the physicians' choice to prescribe a statin or a fibrate were analysed. METHODS: In total 286 first authorizations for the reimbursement of lipid-lowering drugs were recorded during February and March of 2002 at two regional health insurance offices. We studied a mixed primary and secondary prevention population. RESULTS: The mean age at the initiation of the treatment was 61 years (SD = 12). Mean fasting TC was 285 mg/dl before the diet and 286 mg/dl after the diet. Fasting TC and TG did not decrease with the diet for respectively 51% and 54% of the patients. High TC and an improvement of TG during the diet were the only two factors correlated with the prescription of a statin instead of a fibrate. CONCLUSIONS: Half of the patients receiving lipid-lowering drugs in Belgium were not able to decrease their TC with diet before the initiation of the treatment. Cardiovascular risk factors were not taken into account for the reimbursement of statins. Belgian reimbursement criteria should be adapted.

Prevention and follow-up of cardiovascular disease among patients without a personal GP.

OBJECTIVE: This paper describes the characteristics of Belgian people who declare that they have a personal GP (PGP) compared with those who do not. Furthermore, patterns of cardiovascular prevention and care are described for these two groups. METHODS: The data are derived from the 1997 Belgian Health Interview Survey (HIS) in which a representative sample (n = 10 221) of the Belgian population was questioned. The HIS data about physical activity, food, blood pressure, cholesterol, cardiovascular diseases, diabetes and stroke are analysed. RESULTS: After standardization for age and gender, 7.0% of the subjects declared that they did not have a PGP. The mean age of patients without a PGP (33.2 +/- 20.4 years) is significantly lower than for those with a PGP (40.4 +/- 22.7 years) (P < 0.001). More smokers (38.5% compared with 28.5%) were reported among the subjects without a PGP (P < 0.001). For 14.8% of the subjects without a PGP, their blood pressure had never been measured, and for 51.1% their cholesterol had never been measured (6.7% and 35.7%, respectively in subjects with a PGP). Among the subjects without a PGP, 3.8% had high blood pressure and 1.5% had a coronary heart disease. Among the hypertensive patients without a PGP, 43.6% are not treated by any physician. CONCLUSION: Subjects without a PGP were less likely to have a healthy way of life. Having a PGP seemed to have a beneficial influence on the screening for and the follow-up of cardiovascular risk factors. However, it has never been confirmed that providing people who do not have a PGP with one would result in health improvements. In particular, cardiac patients without a PGP sought their medical treatment directly from specialists.

Results from a cardiovascular prevention campaign in persons aged 45-64 years.

The aim of this study was to screen a target population for modifiable cardiovascular risk factors and to find out how treatment goals were achieved in the treated population. All inhabitants aged between 45 and 64 years in the town of Lede in Belgium were invited by the local authorities for a free health check-up. In total, 629 subjects were screened. Total cholesterol > or = 250 mg/dl or triglycerides > or = 200 mg/dl was found in 38%, increased fasting glucose (> or = 110 mg/dl) in 8.6%, diabetes in 2.8%, increased systolic blood pressure (SBP) (> or = 140 mmHg) in 22% and increased diastolic blood pressure (DBP) (> or = 90 mmHg) in 8%. The low-density lipoprotein cholesterol (LDL-C) target level of 115 mg/dl was attained in 13% of treated women and 34% of treated men. Target levels for SBP and DBP were attained in 40% and 75% respectively of those treated. Fasting glucose < 120 mg/dl was found in 33% of the diabetic participants.

A "bad responder" to statins.

We report the case of a man whose high-density lipoprotein cholesterol (HDL-C) and the ratios of total cholesterol to HDL-C and low-density lipoprotein cholesterol to HDL-C worsened dramatically during pravastatin treatment. After 3 years, pravastatin was replaced by fenofibrate. The result was spectacular. The HDL-C increased to at least twice the level obtained during pravastatin.

Sustained stimulation of exocytosis triggers continuous membrane retrieval in rat pituitary somatotrophs.

We studied the relationship between exocytosis and endocytosis in rat pituitary somatotrophs using patch-clamp capacitance, FM1-43 fluorescence imaging and amperometry. Stimulation of exocytosis through voltage-dependent Ca2+ channels by depolarizations (1-5 s) increased the capacitance by 4.3 +/- 0.9 % and the fluorescence by 6.6 +/- 1.1 % (10 cells). The correlation between the capacitance and fluorescence changes indicated that the cell membrane and granule membrane added via exocytosis were stained with the membrane-bound fluorescent dye FM1-43 in a quantitatively similar manner. Intracellular dialysis (0.5-4.5 min) with elevated Ca2+ (1.5-100 microM) evoked continuous exocytosis that was detected with a carbon fibre electrode from dopamine-loaded cells (10 cells) or as an increase in FM1-43 fluorescence (56 +/- 10 %; 21 cells). Interestingly during Ca2+ dialysis the capacitance did not significantly change (2 +/- 1 %; 31 cells), indicating that endocytosis efficiently retrieved increased cell membrane. Sustained endocytosis was not blocked when the intracellular GTP (300 microM) was replaced with GTP[gamma]S. Replacing intracellular Ca2+ (100 microM) with Ba2+ (300 microM) or Sr2+ (200 microM), or reducing the pH of the intracellular solution from 7.2 to 6.2 did not block sustained endocytosis. Our results suggest that pituitary somatotrophs have the ability to undergo continuous exocytosis and membrane retrieval that persist in whole-cell recordings.

Effects of staurosporine on exocytosis and endocytosis at frog motor nerve terminals.

Observations of the dynamic staining and destaining of FM1-43 in frog motor nerve terminals (Henkel and Betz, 1995) suggested that staurosporine might shorten the interval between exocytosis and endocytosis, inducing a "kiss and run" mode of exocytosis and endocytosis. We tested this hypothesis by using FM1-43 imaging (to measure the time course of FM1-43 endocytosis), intracellular recording of evoked synaptic potentials (to measure acetylcholine release), and electron microscopy (to examine synaptic vesicle distribution). Staurosporine reduced FM1-43 uptake during but not after a tetanus, increased the speed of end plate potential (EPP) amplitude rundown, and greatly slowed the recovery from synaptic depression. Ultrastructural observations showed pronounced vesicle depletion near active zones after tetanic stimulation in staurosporine-treated preparations. These results suggest that staurosporine acted primarily to impair mobilization of synaptic vesicles during tetanic stimulation.

Intraterminal Ca(2+) and spontaneous transmitter release at the frog neuromuscular junction.

We investigated the relationship between intraterminal Ca(2+) concentration ([Ca(2+)](i)) and the frequency of miniature end plate potentials (MEPPs) at the frog neuromuscular junction by use of ratiometric imaging of fura-2-loaded nerve terminals and intracellular recording of MEPPs. Elevation of extracellular [KCl] over the range of 2-20 mM resulted in increases in [Ca(2+)](i) and MEPP frequency. Loading terminals with the fast and slow Ca(2+)-buffers bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid-acetoxymethyl (BAPTA-AM) and EGTA-AM resulted in equivalent reductions in the KCl-dependent increases in MEPP frequency. The [Ca(2+)](i) dependence of MEPP frequency determined by elevation of [Ca(2+)](i) due to application of 0.1-10 microM ionomycin was similar to that determined when [Ca(2+)](i) was raised by increasing extracellular KCl. Measurements in 10 mM extracellular KCl revealed that application of the phorbol ester phorbol 12 myristate 13-acetetate (PMA) caused an increase in MEPP frequency while the inactive analogue, 4 alpha-PMA, did not. PMA application also caused an increase in [Ca(2+)](i). The relationship between [Ca(2+)](i) and MEPP frequency in PMA was the same as was determined by the other methods of raising [Ca(2+)](i). Under all conditions tested, our data revealed a low [Ca(2+)](i) threshold for activation of transmitter release and are consistent with a K(d) for [Ca(2+)](i) on the order of 1 microM.

Two endocytic recycling routes selectively fill two vesicle pools in frog motor nerve terminals.

We have identified and characterized two vesicle recycling pathways in frog motor nerve terminals. We exploited the differential staining properties of FM dyes of varying hydrophobicity to label selectively two different vesicle pools, using optical imaging and electron microscopy of photoconverted dyes. During a 1 min tetanus, a rapidly recycling route places vesicles selectively into a small readily releasable pool comprising about 20% of vesicles. After the tetanus, a much slower pathway (from which FM2-10 but not FM1-43 can be rinsed) delivers vesicles via infoldings and cisternae selectively to a reserve pool with a halftime of about 8 min. Mixing between the two pools is slow. During stimulation at 30 Hz, 10-15 s is required to mobilize and release dye from the reserve pool.

Differential regulation of granule-to-granule and granule-to-plasma membrane fusion during secretion from rat pituitary lactotrophs.

We used fluorescence imaging of individual exocytic events together with electron microscopy to study the regulation of dense core granule-to-plasma membrane fusion and granule-to-granule fusion events that occur during secretion from rat pituitary lactotrophs. Stimulating secretion with elevated extracellular potassium, with the calcium ionophore ionomycin, or with thyrotropin releasing hormone or vasoactive intestinal polypeptide resulted in abundant exocytic structures. Approximately 67% of these structures consisted of multiple granules fused together sharing a single exocytic opening with the plasma membrane, i.e., compound exocytosis. For all of these stimulation conditions there appeared to be a finite number of plasma membrane fusion sites, approximately 11 sites around each cellular equator. However, a granule could fuse directly with another granule that had already fused with the plasma membrane even before all plasma membrane sites were occupied. Granule-to-plasma membrane and granule-to-granule fusion events were subject to different regulations. Forskolin, which can elevate cAMP, increased the number of granule-to-granule fusion events without altering the number of granule-to-plasma membrane fusion events. In contrast, the phorbol ester PMA, which activates protein kinase C increased both granule-to-granule and granule-to-plasma membrane fusion events. These results provide a cellular mechanism that can account for the previously demonstrated potentiation of secretion from lactotrophs by cAMP- and PKC-dependent pathways.

Spatial variability in release at the frog neuromuscular junction measured with FM1-43.

We quantified the spatial variability in release properties at different synaptic vesicle clusters in frog motor nerve terminals, using a combination of fluorescence and electron microscopy. Individual synaptic vesicle clusters labeled with FM1-43 varied more than 10-fold in initial intensity (integrated FM1-43 fluorescence) and in absolute rate of dye loss during tetanic electrical nerve stimulation. Most of this variability arose because large vesicle clusters spanned more than one presynaptic active zone (inferred from postsynaptic acetylcholine receptor stripes labeled with rhodamine-conjugated alpha-bungarotoxin); when the rate of dye loss was normalized to the length of receptor stripe covered, variability from spot to spot was greatly reduced. In addition, electron microscopic measurements showed that large vesicle clusters (i.e., those spanning multiple active zones) were also thicker, and the increased depth of vesicles led to increased total spot fluorescence without a corresponding increase in the rate of dye loss during stimulation. These results did not reveal the presence of "hot zones" of secretory activity.