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Biomedical subjects

H Wiese

Publications and source records attributed to H Wiese.

At least 19 recordsLinked to original sources
PubMed2005

Prospective PC-interactive pressure algesimetry of post-traumatic neck pain after whiplash injury.

Cervical pain is a prominent symptom in both acute whiplash injury and late whiplash syndrome. However, no systematic analysis of post-traumatic pain development covering several weeks has yet been performed in whiplash patients. It was the aim of the present study to analyse the duration and course of post-traumatic muscle pain due to whiplash injury in a prospective follow-up examination with short investigation intervals. A recovery of initially increased muscle pain after whiplash injury within 1 month was hypothesized. Pressure pain of the splenius and trapezius muscles was recorded using PC-interactive pressure algesimetry. Whiplash patients were investigated during the acute injury stage and after 3, 4, and 6 weeks and compared with matched controls. We found significantly increased pressure pain of the splenius and trapezius muscles in the acute stage of whiplash injury. After 4 weeks patients' scores of pain parameters were comparable to those of healthy control subjects. Within the patient group the first changes of pressure pain were observed within 3 (splenius) and 4 weeks (trapezius). For most patients the recovery dynamics lasted 4-6 weeks. A minority of patients did not show any improvement after 6 weeks. The present study shows that the dynamics of pressure pain due to whiplash injury can be quantified by means of PC-interactive pressure algesimetry. Our results confirm the clinical experience that the acute post-traumatic cervical syndrome normally subsides within weeks.

Adult↗
PubMed2004

Quantification of acute neck pain following whiplash injury by computer-aided pressure algesimetry.

Until now the clinical investigation of cervical pain due to whiplash injury is mainly based on finger palpation. The present study introduces a PC-interactive pressure algesimetry to standardize cervical pain measurement. Pressure pain scores of the splenius and trapezius muscles of 23 patients with an acute cervical syndrome after whiplash injury were compared to those of 24 healthy subjects. The pressure painfulness of neck and shoulder muscles was significantly increased in whiplash patients. The splenii muscles showed an equally increased muscle pain whereas the trapezii muscles showed a left-sided preponderance of painfulness, possibly due to the seat belt position in this group of motor vehicle drivers. The computer-interactive pressure algesimetry enables a standardized and rater-independent quantification of the cervical syndrome with neck and shoulder pain caused by whiplash injury.

Adolescent↗
PubMed1996

On the mechanism of the post-activation depression of the H-reflex in human subjects.

It was demonstrated that the soleus H-reflex was depressed for more than 10 s following a preceding passive dorsiflexion of the ankle joint. This depression was caused by activation of large-diameter afferents with receptors located in the leg muscles, as an ischaemic block of large-diameter fibres just below the knee joint abolished the depression, whereas a similar block just proximal to the ankle joint was ineffective. The depression of the H-reflex was not caused by changes in motoneuronal excitability, as motor-evoked potentials by magnetic brain stimulation were not depressed by the same passive dorsiflexion. Therefore it was concluded that the long-lasting depression is due to mechanisms acting at presynaptic level. The transmission of the monosynaptic Ia excitation from the femoral nerve to soleus motoneurones was not depressed by the ankle dorsiflexion. The depression thus seems to be confined to those afferents that were activated by the conditioning dorsiflexion. In parallel experiments on decerebrate cats, more invasive methods have complemented the indirect techniques used in the experiments on human subjects. A similar long-lasting depression of triceps surae monosynaptic reflexes was evoked by a preceding conditioning stimulation of the triceps surae Ia afferents. This depression was accompanied by a reduction of the monosynaptic Ia excitatory postsynaptic potential recorded intracellularly in triceps surae motoneurones, but not by changes in the input resistance or membrane potential in the motoneurones. Stimulation of separate branches within the triceps surae nerve demonstrated that the depression is confined to those afferents that were activated by the conditioning stimulus. This long-lasting depression was not accompanied by a dorsal root potential. It is concluded that the long-lasting depression is probably caused by a presynaptic effect, but different from the "classical" GABAergic presynaptic inhibition which is widely distributed among afferent fibres and accompanied by dorsal root potentials. It is more probably related to the phenomenon of a reduced transmitter release from previously activated fibres, i.e. a homosynaptic post-activation depression. The consequences of this post-activation depression for the interpretation of results on spinal mechanisms during voluntary movements in man are discussed.

Adult↗
PubMed1994

X-ray kinematography as a tool for investigations of distal limb movements of the cat.

X-ray kinematography was used to investigate the kinematics of cat distal forelimb joints during motor behaviour. These joints are not accessible for instrumentation with external markers normally used in conventional motion analysis systems. To trace the movements in space two X-ray systems positioned rectangularly to each other illuminated the forelimb quasi-simultaneously with pulsed X-ray shots (time resolution: 20 ms). A mathematical model was developed for 3-dimensional reconstruction of the object and includes procedures for correction of image distortions, e.g., pincushion distortions and rotation of the image due to interaction of the earth's magnetic field with the electron optics of the image amplifiers. Accuracy of image correction and object reconstruction is +/- 1 pixel, corresponding to +/- 0.5 mm in space which is sufficient for investigation of the kinematics of cat distal forelimb joints. The approach described is of general relevance and useful in kinematic investigations where the structures under study are not directly accessible to external instrumentation with markers.

Animals↗
PubMed1992

Limitations of clearance determination using the single sample distribution volume method. An error analysis on the basis of compartment models.

To investigate the error possibly contained in the single sample distribution volume method for the determination of renal clearance, a mathematical model was applied to describe the effect of changes in distribution volume, clearance, intravascular space, intracompartmental exchange and the time point of blood sampling. The method was found to be valid only under well-defined circumstances (Topt = 45 +/- 5 min, Cl = 390 +/- 50 ml/min, Vd = 16.7 +/- 4 l, alpha = 0.05.V1 ml/min, V1/Vd = 0.5 +/- 0.05) as shown in sample calculations. Two-compartment model-based error calculations demonstrate that this technique implies at best an uncertainty of +/- 10% or more. Whilst it can be used preferably in healthy, normal-weight adults, it is not applicable, without error, under all other circumstances.

Humans↗
PubMed1992

Electroencephalography and evoked potentials: a PC-based analysis program for laboratory courses in physiology.

A computer program (EEG Analysis) was developed for the preclinical laboratory course in physiology held for medical and dental students. It offers an off-line analysis of a set of typical and frequently occurring physiological and pathological electroencephalogram (EEG) and evoked potential (EP) recordings, which are stored in an IBM-compatible personal computer (PC) system. The users are requested to measure and analyze the data sets and to work through a base of questions relevant in the frame of the particular topic. The program is structured in several exercises: calibration, pickup of non-EEG signals (eye movements, chewing), waveforms in EEG recordings from awake subjects (alpha-waves, beta-waves), desynchronization of cerebral activity (visual activation, acoustic activation, mental activation), habituation of cerebral activity upon acoustic stimuli, EEG recordings from asleep subjects (different sleep stages, sleep-specific EEG signals), epileptic seizures, and EPs (principle of averaging, visually evoked potentials in different cortical areas). The program runs under MS-DOS and is network capable. The software structure ensures maximal flexibility for rapid changes and adaptations of the program to specific needs of a particular EEG course. The program has been used for three years, and the response from > 800 students has been consistently positive.

Acoustic Stimulation↗
PubMed1992

[Mucociliary clearance in childhood].

AIM OF THE STUDY: A new, nearly monodisperse human serum albumin particle produced by air-pressure-nebulization was inhaled by children and lung-transplant patients. METHOD: After inhalation of the particles obtained with an air-pressure nebulizer, the initial deposition pattern showed a marked tracheobronchial deposition which could be reproducibly obtained without a special breathing technique, the alveolar deposition being not higher than 10%. With the use of 99mTc, the radiation exposure is limited to a level which is low enough for children, but images can be taken up to 24 hrs later. Further parameters for in vivo characterization of the mucociliary function are the 24 h retention pattern and the velocity of particle motion in the trachea. RESULTS: Within the first 45 minutes, the global clearance rate was 51% in healthy children, which is rather high in comparison with the literature, most likely due to size of particles and the selection of patients with a mean age of 10.7 years. In ciliary dysfunction, the initial clearance rate was 16% and 46% within 24 h. CONCLUSIONS: With simplification of the preparation, application, and examination technique, this method is to be used in children, so that a wider use can be anticipated. The normally fast initial elimination of particles allows quick differentiation of normal and impaired ciliary function.

Adolescent↗
PubMed1989

Acute facilitory action of progesterone on gonadotropin secretion of perifused rat pituitary cells.

The purpose of this study was to investigate the kinetics and estrogen dependence of the facilitory progesterone action on LH and FSH secretion from pituitary cells under dynamic culture conditions. Anterior pituitary cells obtained from ovariectomized or intact adult Wistar rats were cultivated on Cytodex 1 microcarrier beads. The perifusion experiments were performed with four separate perfusion chambers. The cells of chambers I + II had been pretreated with medium containing vehicle (0.1% ethanol), those of chambers III + IV with medium containing 1 nmol/l estradiol for 48 h. After perfusion was started, each of the chambers was challenged with an initial 2-min GnRH (1 nmol/l) pulse. Chamber I was further perifused with medium containing vehicle, chamber II with medium containing vehicle + 100 nmol/l progesterone, chamber III with medium containing 1 nmol/l estradiol, and chamber IV with medium containing 1 nmol/l estradiol + 100 nmol/l progesterone. Three further GnRH pulses were administered at 50-min intervals to each of the chambers. In estradiol-primed cells from intact rats, progesterone induced a positive effect on LH and FSH secretion after 50 min of exposure to progesterone. After 100 min of progesterone treatment, LH and FSH release were enhanced to 420 and 500 per cent, respectively. When such cells were not primed with estradiol, a slight though insignificant positive action of progesterone on LH release was present after 50 and 100 min of treatment, whereas FSH secretion was not influenced. The facilitory effect of progesterone occurred only after 100 min when estradiol-primed cells from ovariectomized rats were used.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Screening for pheochromocytoma in the MEN 2 syndrome.

Twenty-two patients with the multiple endocrine neoplasia type 2 (MEN 2) syndrome were screened for pheochromocytoma since it is a major cause of morbidity in MEN 2 families. Clinical symptoms, biochemical parameters, ultrasound, computed tomography or magnetic resonance imaging, and meta-iodo-benzylguanidine (MIBG) scintigraphy were evaluated for detection of adrenal tumors. Clinical symptoms and plasma or urine catecholamines appeared to be nonspecific, whereas MIBG scintigraphy was highly specific and the most sensitive parameter. Patients older than age 30 should be scintigraphically screened at least once despite the radiation exposure. Demonstration of only slight uptake is not an indication for surgery but rather for careful follow-up.

3-Iodobenzylguanidine↗
PubMed1988

Minimizing the influence of the series resistance in potential clamped Ranvier nodes.

Series resistance artifacts in ionic current measurements on single myelinated nerve fibres are commonly minimized by reducing sodium currents. Doing this some deviations from the predictions of the Hodgkin-Huxley-Frankenhaeuser formalism become evident. In the present investigation two methods to reduce sodium currents were used with and without compensated feedback to examine the influence of the nodal series resistance. Changing the availability of sodium permeability by appropriate prepulses peak sodium current-voltage relations obeyed the Hodgkin-Huxley-Frankenhaeuser formalism only provided the amount of compensated feedback was set to give minimum of the current-voltage relation near E = 0. For reduced sodium concentration in the bathing fluid the so-called independence principle predicts a shift of the minimum of the current-voltage relation on the potential axis in negative direction as compared to ordinary Ringer solution, if the effective series resistance is sufficiently small. This was confirmed by experiments only if the above mentioned amount of compensated feedback was used. The results suggest that the "E = 0"-criterion indicates optimum compensation of the influence of the series resistance.

Animals↗