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Biomedical subjects

D Claus

Publications and source records attributed to D Claus.

At least 127 records · Page 7Linked to original sources
PubMed1990

Thermal discrimination thresholds: a comparison of different methods.

Thermal testing was carried out on 55 healthy subjects in order to establish normal results and reproducibility of warm and cold thresholds. Diurnal variations of thresholds were investigated in a further 30 normal subjects. Then the sensitivity of different testing procedures was investigated in 33 patients with diabetes mellitus, but without severe polyneuropathy. Forced choice testing takes 6 times longer than the method of limits, and the results are not considerably different. It is thought that the forced choice algorithm does not provide a method for clinical routine. Another new approach, the double random staircase method, may help to exclude bias without taking too much time.

Adolescent↗
PubMed1990

Transient cyst-like cortical defects following fractures in children. Medullary fat within the subperiosteal haematoma.

Asymptomatic cyst-like cortical defects appearing after fractures in children have been occasionally reported. Typically, these defects appear during fracture consolidation, within the newly formed subperiosteal bone, proximal to the fracture line, do not enlarge, and progressively disappear. We have previously shown a fatty density on CT scan within the early cortical defect. We now present two additional cases in which early CT scans appeared to confirm that these transient cortical defects may consist of fat, and probably result from the inclusion of medullary fat within the subperiosteal haematoma.

Adipose Tissue↗
PubMed1990

[Transcutaneous cardiac pacemaker for prevention and emergency therapy in neurologic intensive care patients].

In a number of neurological diseases, e.g. Guillain-Barré syndrome, patients are at high risk for a bradyarrhythmia or asystolia. Sometimes a cardiac pacemaker is needed for prophylaxis or for emergency therapy. The usual temporary insertion of a transvenous stimulating electrode has many disadvantages and a high incidence of complications. We report on our initial experience with the non-invasive technique of transcutaneous stimulation via superficial electrodes. The advantages of this method are discussed.

Adolescent↗
PubMed1990

[The value of echographic studies in congenital hip dislocation].

Since the studies of R. Graf has echography of the hip replaced the standard X-Rays of the pelvis in the early diagnosis of CDH after birth. The authors report their experience with this technique in 400 newborn children. The technical aspects and results are described. The study is original because the pediatric orthopaedic surgeon does simultaneously the clinical examination under echographic control.

Hip Dislocation, Congenital↗
PubMed1990

[Inductive stimulation].

Electrical stimulation, which has long been known, has recently been complemented by electromagnetic stimulation. This method is based on the law of induction and employs coils in place of electrodes. The effect of this process is deduced from both the relationship between magnetic and electrical fields and the stimulating effect. A new type of stimulator has been developed from a resonant circuit, thus allowing nerves to be excited with low-frequency pulses up to fusion frequency.

Animals↗
PubMed1989

Intensive care for children after orthotopic liver transplantation.

We report our experience in the management of children after orthotopic liver transplantation (OLT). From 03/84 to 04/87 50 patients (pts) were transplanted. Mean age was 4 3/12 years (8/12 to 13 2/12) and mean body weight 14.7 kg (5.8 to 40). Hospital mortality was 14%. Problems related to the surgery included: Abdominal complications: bleeding (8 pts), infection (18 pts), ascites and fistula (1 pt), need for secondary abdominal surgery (10 patients). Respiratory problems: lobar atelectasis (11 pts), right diaphragmatic paralysis (2 pts) and right pleural effusion (11 pts). Problems related to immunosuppression included: Bacterial infection (29 pts) fungal infection (5 pts), one patient died of disseminated cytomegalovirus infection. Side effect of cyclosporin A (CsA) were systemic blood hypertension (S.B.H.) (47 pts), sinusal bradycardia (37 pts), associated to SBH (24 pts), hypertensive encephalopathy (2 pts). Generalized seizures (2 pts in the absence of SBH). Renal side effects of CsA were hypercreatininemia, decreased sodium bicarbonate and hyperkaliemia. The nephrotoxicity of CsA was favoured by the use of other nephrotoxic drugs such as aminoglycosides, amphotericin B. Edematous pancreatitis was observed in 3 patients and related to the use of large doses of steroids. Problems related to the functioning of the graft included: Primary non-function of the graft (4 pts), hepatic artery thrombosis (8 pts) and severe acute rejection unresponsive to therapy (1 pt); these situations needed to be recognised early in order to organize a second OLT. Other causes of hepatic dysfunction were: portal vein thrombosis (1 pt), biliary tract obstruction (2 pts), angiocholitis (3 pts), right hepatic lobe necrosis (2 pts). Acute hepatic insufficiency in 7 children.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Changes in human alpha-motoneurone excitability following mechanical muscle stimuli.

Short mechanical stretches given to partially activated human abductor digiti minimi muscle (ADM) evoke early (M1) and late (M2) reflex responses. Transcranial magnetic brain stimuli were used to evoke compound muscle action potentials in ADM and hence to estimate motoneuronal excitability at various times after mechanical stimuli. There was no evidence that Ia volleys produce additional facilitation in motoneurones of muscles which are already voluntarily activated. However, the inhibitory phase between M1 and M2 was associated with a reduction in size of muscle responses from brain stimuli. This may reflect reduced Ia input, polysynaptic Ia inhibition or Renshaw inhibition.

Adult↗
PubMed1989

Obstruction to hepatic venous drainage after liver transplantation: treatment with balloon angioplasty.

Stenosis of the suprahepatic inferior vena caval anastomosis is a rare but serious vascular complication after liver transplantation. It may cause significant obstruction to venous drainage from the allograft liver and result in the Budd-Chiari syndrome with massive ascites and pleural effusion causing respiratory compromise. The authors report two such cases in which percutaneous transluminal angioplasty (PTA) of the stenotic anastomosis was performed. This nonsurgical approach resulted in resolution of ascites, pleural effusion, and respiratory distress in both patients. They conclude that PTA is a therapeutic alternative with minimal risk compared with surgical repair or retransplantation and should be considered the initial treatment of choice in selected patients.

Angioplasty, Balloon↗
PubMed1989

[The study of the central motor conduction time to the leg: normal findings and methodologic observations].

Central motor conduction time (CMCT) is calculated by subtracting latencies from each other measured to a target muscle after transcranial brain stimulation and after stimulation of lumbar spinal nerve roots. Transcranial magnetoelectrical stimulation of the motor cortex has proved to be the most useful method. However this is not true for transcutaneous stimulation of lumbar roots. In healthy subjects electrical root stimuli given at T12/L1 produced compound muscle responses in Tibialis anterior muscles in all 18 trials. However, magnetoelectrical stimulation (100% stimulus strength) evoked responses in only 8 (Novametrix) and 12 out of 18 trials (Cadwell). Stimulation with the Digitimer D190 was less effective. Additionally compound responses after electrical root excitation were more consistent and they had a higher amplitude compared with magnetoelectrical stimulation. Regarding to these results electrical lumbar root stimulation is thought to be the advantageous method despite it is slightly more uncomfortable. Therefore normal results of CMCT to Tibialis anterior (shown in Table 1) are measured after magnetoelectrical transcranial (Digitimer D190) and transcutaneous electrical stimulation of spinal nerve roots. If the peripheral motor conduction is delayed normal values have to be adapted since CMCT is thought to involve a proximal anterior root segment. An intraspinal motor conduction time can be calculated from CMCT to upper and lower extremities.

Brain↗
PubMed1989

[Urodynamic and electrophysiologic studies in evaluating congenital neurogenic bladder].

We investigated 50 patients with a congenital neurogenic bladder secondary to myelomeningocele (38), sacral agenesis (5) and occult spinal dysraphism (7). There were 25 males and 25 females, aged from 1 month to 29 years (mean age at the time of evaluation was 9.2 years). Pressure-Flow-EMG study was obtained in every instance. In addition, 25 patients underwent electrophysiological testing (sacral reflex arc testing and somatosensory evoked potentials from the pudendal nerve). The patients were then classified according to the urodynamic and electrophysiological results. We allocated the patients into a "functional" classification as recommended by Van Gool. This classification is useful in the selection of proper therapy, and in the definition of the risks of upper tracts deterioration.

Adolescent↗
PubMed1989

[Sexual ambiguity: urologic aspects].

Ambiguous genitalia require prompt decision in the neonatal period to give the child the best opportunity to avoid later major problems of sexual identification. A team approach including the neonatologist, the pediatric endocrinologist, the geneticist and the pediatric urologist seems to be the best way to make the right decision. This paper is a review of 48 cases of ambiguous genitalia referred to our center for management. The diagnosis of female pseudohermaphroditism was established in 30 cases with 21 presented with adrenogenital syndrome. Ten patients were considered as having a diagnosis of male pseudohermaphroditism, six presented with gonadal dysgenesis and two were true hermaphrodites. Principles of surgical management for each category of patients is exposed, discussed and will be the way to treat subsequent cases.

Disorders of Sex Development↗
PubMed1989

[Differential diagnosis of Friedreich ataxia].

The clinical records of 72 patients with spinocerebellar ataxias which had manifested before the age of 20, were examined in a retrospective study. Depending on whether the muscle stretch reflexes in the legs were positive or negative, two groups were distinguished, that of early onset cerebellar ataxia with retained tendon reflexes (EOCA) (13 P.) and that of Friedreich's ataxia (FA) (59 P.). The clinical course was much worse in the FA patients compared with EOCA. Cardiomyopathy and diabetes mellitus were not a feature of EOCA. Scoliosis and a disturbed position sense in the toes were more frequent in FA cases. The striking differences in clinical signs and course of the diseases justify the differentiation of EOCA from FA, as suggested by Harding in 1981.

Adolescent↗
PubMed1988

Effect of desynchronized inputs on compound sensory and muscle action potentials.

Stimulation of the second (S1) or third (S2) digit elicits a median sensory potential at the wrist. Similarly, a shock applied to the median (Sm) or ulnar (Su) nerve at the wrist evokes a sensory potential of the fourth digit and a muscle potential over the thenar eminence. Hence, a concomitant application of S1 and S2 or Sm and Su with varying interstimulus intervals simulates the effect of desynchronized inputs. In 10 hands, a shift in latency on the order of 1 msec between S1 and S2 or Sm and Su caused a major reduction in sensory potential by as much as 30-40% but little change in muscle action potential. A latency difference slightly less than one-half the total duration of unit discharge maximized the phase cancellation between the two components and consequently the loss of area under the waveform.

Action Potentials↗
PubMed1988

Facilitation of muscle responses to magnetic brain stimulation by mechanical stimuli in man.

Transcranial magnetic brain stimuli were applied to 9 normal subjects and compound muscle action potentials were recorded from the right abductor digiti minimi with surface electrodes. Vibration of 120 Hz, 0.6 mm peak to peak amplitude, applied to the muscle tendon enhanced its responses to magnetic brain stimuli. This facilitation corresponds to the tonic vibration reflex. Inhibition of muscle responses was not seen with vibration. Thus it is likely that the known inhibition of stretch reflexes by vibration is purely presynaptic. Small rectangular mechanical stimuli (rise time 200 mm/s, amplitude 1 mm) applied to ADM elicited short and long loop reflex responses. When brain stimuli were give 7-16 ms after the muscle tap, muscle responses were enhanced. It is argued that this is a result of the summation of the effects of Ia afferent impulses and descending pyramidal volleys at the alpha motoneurones. A separate late facilitation corresponding with the arrival of muscle afferent inputs to the sensori-motor cortex was not seen.

Action Potentials↗