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Biomedical subjects

D Wenzel

Publications and source records attributed to D Wenzel.

At least 73 records · Page 4Linked to original sources
PubMed1977

Selective deprivation of sleep in pycnoleptic children. Effects of deprivation of slow-wave and REM sleep on the frequency and duration of petit mal attacks.

1. Selective deprivation of slow-wave and paradoxical sleep was performed in 10 children with pycnoleptic attacks (8 of them before anticonvulsive treatment, 2 of them while under medication). The frequency and duration of petit mal attacks were intraindividually compared during night sleep and after waking for a 5-h period. 2. After deprivation of slow-wave sleep with reduction of EEG stages 3 and 4 to about one-third of the baseline but normal duration of sleep, petit mal attacks are more frequent and long-lasting than after normal sleep or selective deprivation of REM sleep. 3. Although total sleep time is significantly diminished after selective deprivation of paradoxical sleep the frequency of attacks during the waking state was lower than after normal sleep and deprivation of slow wave sleep. This observation shows a clear i nfluence of the quality of sleep on the frequency of epileptic attacks. 4. During sleep petit mal seizures were mainly found during stages 2 and paradoxical sleep. Single spike and irregular spike were discharges, however, occurred more frequently during slow-wave sleep. Their frequency was not significantly different in the deprivation conditions. 5. In contrast to experimental data in animals, REM deprivation is less provoking to epileptic attacks outside sleep than deprivation of stages 3 and 4 sleep. Therefore a sufficient amount of slow-wave should be preserved for pycnoleptic children.

Child↗
PubMed1977

The comparison of small-size rectangle and checkerboard stimulation for the evaluation of delayed visual evoked responses in patients suspected of multiple sclerosis.

The use of foveal small-size rectangle stimulation to elicit visual evoked responses was compared with VERs elicited by the standard checkerboard pattern. Foveal stimulation achieved a significantly better discrimination of optic nerve lesions in the early diagnosis of multiple sclerosis. Sources of misdiagnosis due to different neurological disorders are discussed.

Adolescent↗
PubMed1976

[Visual stabilization of free stance in infants: a sign of maturity (author's transl)].

The development of the visual contribution to postural stabilization has been tested using a large visual display rotating around the stationary subject's line of sight. This, in the adult, causes a marked optokinetic postural reaction with a shift of the body center of gravity toward the direction of pattern motion. Scalings of the reactions in children between 6 months and 16 years revealed three phases of development: (1) 6--12-month-old-babies show none or very little optokinetic disturbance of their newly acquired ability to sit. With the development of upright stance and gait, optokinetic influences become increasingly important. (2) Children between the age of 2--5 show a marked dependence of postural stability on vision. In them, the disturbing optokinetic stimulus leads to a marked ipsilateral postural deviation or irresistible fall. (3) From 5 to 15 years of age, visual effects on postural balance slowly decrease to their final strength in adulthood--moderate head and body tilt--in response to the rotating stimulus. It is concluded that the optokinetic loop participates rather late in the multisensory process of postural stabilization. The calibration of the three main loops, visual, vestibular, and proprioceptive, seems to be sequential and mutually interactive. Optimal functioning requires the continuous evaluation of the reafferent sensory consequences of self-generated body movements. Optokinetic destabilization of stance requires the maturity of opto-vestibulo-spinal pathways. Its clinical applicability as a maturity test, however, sofar seems limited.

Adolescent↗
PubMed1976

[Clinical ergometry in cardio-pulmonary functional disorders--a comparison of the usual ergometric technics].

It is reported on the results of a comparative examination of 18 patients with two usual ergometric methods (team pathophysiology of respiration and research group diseases of heart and circulation of the GDR). Referred to the intake of oxygen as a measure for the stress of the cardiorespiratory system by means of the ergometric methods recommended by the research group diseases of heart and circulation significantly higher minute volumes of the heart rate were established. Principal differences in the evidence of the two methods did not appear.

Adolescent↗
PubMed1976

The development of the blood-CSF barrier after birth.

The serum/CSF concentration ratio of alpha-2-macroglobulin is used as parameter to follow the development of the blood-CSF barrier throughout childhood. The decline of the protein permeability within the first year of life has all characteristics of a maturation process. The tightening of the barrier is thought to be the last stage of a continuous developmental process of capillaries. It is accompanied by a compositional shift in favour of small molecular serum proteins.

Adolescent↗
PubMed1975

[Studies on the limitation of the body functional capacity by the pulmonary function in chronic bronchitic patients in the work process].

It is reported on first experiences (18 patients) with investigation of the breathing mechanism during ergometry for the quantification of the respiratory dyspnoea on exertion. The oesophagus-pressure-method is recommended as suitable method. The stopping of the load on account of dyspnoea in the number of patients which above all consisted of obstructive bronchitics was carried out at values for the total breathing capacity (Wtot) of 5 kpm/min and more.

Adult↗
PubMedDate not supplied

Isolation of Legionella pneumophila serogroup 3 from pericardial fluid in a case of pericarditis.

A 43-year-old woman was hospitalized for fulminant pericarditis. During diagnostic work-up, an as yet unknown bronchial carcinoma was detected. In the pericardial exudate Legionella pneumophila serogroup 3 was demonstrated by direct fluorescent antibody technique and by culture. In a lung biopsy L. pneumophila serogroup 3 was found, too. Using an antigen-ELISA for L. pneumophila serogroup 1, antigenuria was demonstrated. In cases of pericarditis negative for common bacterial pathogens, all diagnostic tests for legionellae, e.g. culture, antigen detection in pericardial, pleural effusion and urine and antibody detection should be included in the diagnostic programme.

Adult↗
PubMedDate not supplied

[Acoustically evoked brain stem potentials in infants with velum clefts].

Brainstem acoustic evoked responses were recorded from 37 infants with cleft palate. Only 35% presented normal auditory thresholds. 27% had a bilateral 22% a unilateral hearing deficit of more than 30 dB. Controls after operative closure of the cleft showed no improvement of the conductive hearing loss.

Auditory Threshold↗
PubMedDate not supplied

[Functional disorder of the hypothalamic osmoreceptor as the cause of excessive hypernatremia in a girl with absence epilepsy].

BACKGROUND: Chronic hypernatremia is a rare disorder in childhood and normally results from impairment of the water homeostasis. In some cases, chronic hypernatremia is caused by decreased intake of water based on impaired thirst perception. CASE REPORT: We report a girl with microcephaly, partial agenesis of the corpus callosum, mild midface hypoplasia and absence seizures, who presented with severe hypernatremia (serum sodium concentration 189 mmol/l). Though serum osmolality was increased up to 382 mOsm/kg, the girl showed no signs of thirst. After normalization by intravenous fluid therapy, serum osmolality and serum sodium concentration remained in the normal range with an oral water intake of at least 1500 ml/d. Polyuria was never present, the ability to concentrate urine was preserved. CONCLUSIONS: In summary, we speculate that the chronic hypernatremia in our patient is caused by a selective hypothalamic osmoreceptor dysfunction associated with mild dysplasia of the midline structures. Only very few similar cases have been documented in the literature.

Agenesis of Corpus Callosum↗
PubMedDate not supplied

[Extra-cerebral intracranial fluid collections in childhood: differentiation between benign subarachnoid space enlargement and subdural effusion using color-coded duplex ultrasound].

BACKGROUND: Extracerebral fluid collections in infancy are a common diagnostic problem, because by noninvasive imaging studies (including cranial ultrasonography, CT and NMR), no definite differentiation between two distinct pathological conditions can be found until today: An enlargement of the subarachnoid spaces in children with macrocephaly is a frequent observation of mostly unknown etiology but is known to be associated with a good prognosis. If surgery is necessary in these patients, ventricular shunting is required. On the other hand subdural effusions are often of traumatic origin and require frequently neurosurgical intervention (subdural shunting). Most reports on extracerebral fluid collections in infancy have not differentiated between both pathological conditions and therefore reveal confusing results. Recent studies using magnetic resonance imaging have shown that vascular flow phenomena in the arachnoid space can be used to a reliable diagnosis, whereas previous noninvasive neuroimaging attempts including high resolution computerized tomography (CT) have been useless. PATIENTS AND METHODS: We investigated a cohort of 20 patients aged 4 mths to 30 mths (mean 10.5 +/- 6.6 months) 16 with the history of macrocephaly and normal neurological development and 4 patients after head trauma and symptoms of an elevated intracranial pressure. RESULTS: In all 16 patients with the clinical diagnosis of benign subarachnoid space enlargement colour coded Doppler sonography detected archnoid vessels within the fluid collection, furthermore high resolution ultrasound demonstrated the dural border of of the arachnoidea as an echogenic membrane, an observation useful as a further sign of the subarachnoid location of the fluid collection. In the 4 patients with subdural hematoma the fluid collection showed an increased echogenity, no vascular structures and no surrounding border. CONCLUSION: Out of these observations we conclude that high resolution ultrasound and colour-Doppler sonography are able to reliably differentiate between a subdural and a subarachnoid fluid collection. An NMR investigation with its higher risks (sedation, anesthesia) focused on this target only seems therefore to be not necessary in these patients.

Blood Flow Velocity↗