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Biomedical subjects

W Betz

Publications and source records attributed to W Betz.

At least 19 recordsLinked to original sources
PubMed2004

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.

Blood Glucose↗
PubMed2004

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.

Adult↗
PubMed2003

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.

Adolescent↗
PubMed2003

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.

Belgium↗
PubMed2003

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.

Aged↗
PubMed2002

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.

Anticholesteremic Agents↗
PubMed2001

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.

Animals↗
PubMed1997

Post-cranioplasty cerebrospinal fluid hydrodynamic changes: magnetic resonance imaging quantitative analysis.

The syndrome of the trephined has been described in many patients with cranial defects as an indication for cranioplasty. Cerebral blood flow changes, the effect of the atmospheric pressure on the brain, as well as cerebrospinal fluid hydrodynamic changes have been postulated as the possible reasons for this syndrome. Using dynamic phase-contrast magnetic resonance imaging we measured arterial, venous, and cerebrospinal fluid flow into and out of the skull, before and after cranioplasty in one patient whose bone flap was removed because of osteomyelitis. We report significant changes in the oscillatory CSF flow after cranioplasty. A moderate increase in venous outflow as well as a two-fold increase in craniocaudal cerebrospinal fluid systolic flow velocity was measured after the skull closure. The changes in the cerebrospinal fluid oscillatory flow at the level of the craniovertebral junction could reflect changes in the compliance of the craniospinal system produced by closure of the cranial defect.

Adult↗
PubMed1977

Effects of innervation on acetylcholine sensitivity of developing muscle in vitro.

1. Chick embryo skeletal muscle fibres were grown in culture. The acetylcholine (AACh) sensitivity of non-innervated fibres was compared with that of fibres innervated in vitro by chick embryo ciliary ganglion neurones. 2. The general pattern of ACh sensitivity was unchanged by innervation: ACh hot spots were superimposed on a background of uniform ACh sensitivity. 3. Quantitative comparisons revealed two differences between non-innervated and innervated fibres. First, hot spots were encountered about one third more often on innervated fibres. Secondly, about one-third of the hot spots on innervated fibres had significantly higher ACh sensitivities than the remainder, which were similar to those on control fibres. 4. Apossible explanation of these results is that nerves which form synapses induce the appearanceof end-plates which have higher ACh sensitivities than the pre-existing ACh hot spots.

Acetylcholine↗
PubMed1977

Properties of isolated adult rat muscle fibres maintained in tissue culture.

1. Adult rat skeletal muscles were dissociated by collagenase treatment and trituration, and the isolated muscle fibres were maintained in vitro for 2-3 weeks. At various stages, the fibres were examined physiologically and morphologically. 2. The isolated fibres underwent some changes characteristic of muscle denervated in vivo. For instance, input resistance increased and extrajunctional acetylcholine (ACh) receptors appeared. In addition, the beginning stages of apparent muscle fibre fragmentation were observed. 3. In other respects, the cultured isolated fibres behaved differently than in vivo denervated fibres. Fibrillation developed only occasionally in vitro. The onset of ACh supersensitivity was slower (6 days) than after denervation in vivo (2-3 days). Some fibres developed localized regions of destriation, which apparently was due to loss of in-register alignment of myofibrils.

Acetylcholine↗
PubMed1976

The formation of synapses between chick embryo skeletal muscle and ciliary ganglia grown in vitro.

1. Chick embryo ciliary ganglia (explanted) and skeletal muscle (dissociated) were grown together in vitro for up to 3 weeks. Nerve processes sprouted from the ganglia and contacted neighbouring myotubes and striated muscle fibres. 2. Spontaneous action potentials and subthreshold e.p.p.s. were recorded from muscle fibres with intracellular micropipettes. Similar potentials could be evoked by electrical stimulation of the ganglion. The pharmacological effects of curare and tetrodotoxin were identical to those observed at adult vertebrate neuromuscular junctions. 3. The amplitude, but not the frequency, of the spontaneous potentials was affected by changing the muscle fibre membrane potential. The reversal potential of evoked synaptic potentials occurred at a membrane potential of about 0 mV.

Action Potentials↗
PubMed1976

Functional and non-functional contacts between ciliary neurones and muscle grown in vitro.

1. In cultures of chick embryo skeletal muscle and ciliary ganglia, muscle fibres near a ganglion were contacted by many individual nerve processes. Experiments were performed to determine if these muscle fibres were multiply innervated, and if any of the nerve-muscle contacts were non-synaptic. 2. Synaptic potentials evoked by electrical stimulation of a ganglion were graded with stimulus strength. When two ganglia were plated near each other, synaptic potentials could be evoked in some muscle fibres by stimulation of either ganglion. These observations suggest that muscle fibres were multiply innervated. 3. Spontaneous synaptic potentials recorded from single muscle fibres with two widely spaced micropipettes varied in a manner which suggested that the synapses were distributed at different points on the surface of the muscle fibres. 4. Stimulation of some nerve processes failed to evoke synaptic potentials in muscle fibres contacted by those processes. Such nerve-muscle contacts were not strongly adhesive, and the nerves were peeled easily from the surface of the muscle with a micropipette. On the other hand, nerve processes which formed synaptic contacts with muscle fibres seemed to be tightly adherent to the muscle. 5. Electron microscopic observations of nerve-muscle contacts revealed that the vast majority of such contacts lacked morphological specializations characteristic of mature neuromuscular synapses.

Animals↗
PubMed1973

Effects of proteolytic enzymes on function and structure of frog neuromuscular junctions.

1. Frog cutaneous pectoris nerve-muscle preparations were incubated with collagenase and protease and examined with electrophysiological and electron microscopic techniques.2. The physiological properties and intracellular ultrastructural appearance of individual muscle and nerve cells were not affected by the enzyme treatment. However, neuromuscular transmission and the morphology of the nerve-muscle junction were altered.3. Collagenase produced an irreversible loss of activity of end-plate cholinesterase and a partial loss of stainable ;synaptic cleft material'.4. Protease produced these changes and, in addition, the entire basement membrane was digested, which led to ;synaptic disjunction' of nerve terminals and muscle end-plates.

Acetylcholinesterase↗
PubMed1971

Does curare affect transmitter release?

1. The effect of curare on the amount of transmitter released by a nerve stimulus was studied in frog and rat nerve-muscle preparations using electrophysiological techniques.2. When the frog sartorius nerve-muscle preparation was exposed to low doses of curare, the amplitudes of spontaneous miniature end-plate potentials and end-plate currents (e.p.c.s, measured under ;voltage clamp' conditions) were reduced to the same extent, suggesting that the drug did not alter the number of transmitter quanta released by nerve stimulation.3. With higher doses of curare in frog muscle treated with glycerol to abolish twitching, quantum content was estimated from the coefficient of variation (CV) of e.p.c.s. The measured CV increased slightly in curare; this increase probably resulted from a relatively greater contribution of random noise to the observed fluctuations when the e.p.c. was reduced by curare.4. In the rat diaphragm, muscle fibres were cut to block twitching. This procedure produced, among other changes, a reduction in the muscle fibre space constant, so that junctional signals were distorted by the cable properties of the muscle fibre when, as often occurred, micro-electrodes were more than 100-200 mu from the end-plate focus. This produced errors in estimates of quantum content; when these errors were accounted for, it appeared that curare did not significantly alter quantum content.5. It is concluded that if curare affects transmitter release at all, its effect must be much smaller than its well known post-synaptic blocking action.

Animals↗