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Biomedical subjects

H Schön

Publications and source records attributed to H Schön.

At least 19 recordsLinked to original sources
PubMed2001

Recurrent infectious mononucleosis caused by Epstein-Barr virus with persistent splenomegaly.

We present the clinical case of a 20-year-old male soldier who appeared in general good physical condition. He suffered from infectious mononucleosis caused by Epstein-Barr virus that had recurred 2 years after the first serologically documented episode. The detected splenomegaly persisted in the healthy young man, who otherwise showed no apparent immune deficiency. To our knowledge, this is an extremely rare condition.

Adult↗
PubMed1999

Induction of complete wound healing in recalcitrant ulcers by low-intensity laser irradiation depends on ulcer cause and size.

Chronic skin ulcers still represent a therapeutic challenge in dermatology. Among the various non-invasive treatment modalities used for the improvement of impaired wound healing, low-intensity laser irradiations are gaining an increasing body of interest. We used low-intensity laser irradiations delivered by a 30 mW helium-neon laser at an energy density of 30 J/cm2 three times weekly for the induction of wound healing in ulcers of diverse causes. Twenty patients with the same number of ulcers, which had previously been treated by conventional wound care for a median period of 34 weeks (range: 3-120 weeks) without any significant evidence of healing, were included in the study. Concerning the underlying disorders, patients were divided into four groups: diabetes, arterial insufficiency, radio damage and autoimmune vasculitis. In all ulcers, complete epithelization could be induced by laser therapy. No amputation or any other surgical intervention was necessary and no adverse effects of any kind were noted during low-intensity laser treatment. Regarding the different diagnoses, a statistically significant difference was noted (P = 0.008): ulcers due to radio damage healed significantly faster than those caused by diabetes (6 weeks [range: 3-10 weeks] vs. 16 weeks [range: 9-45 weeks], P = 0.005). Wound healing in autoimmune vasculitis (24 weeks [range: 20-35 weeks]) required longer than in radiodermitis, although the difference was not significant. In addition to the diagnosis, wound size was found to be an important factor influencing the duration of wound closure (P = 0.028), whereas duration of previous conventional treatment (P = 0.24) and depth (P = 0.14) showed no effect. Our results indicate that low-intensity laser irradiation could be a valuable non-invasive tool for the induction of wound healing in recalcitrant ulcers, and that healing time is correlated with the ulcer cause and size.

Adult↗
PubMed1998

Low-intensity laser irradiation improves skin circulation in patients with diabetic microangiopathy.

OBJECTIVE: Diabetic foot problems due to angiopathy and neuropathy account for 50% of all nontraumatic amputations and constitute a significant economic burden to society. Low-intensity laser irradiation has been shown to induce wound healing in conditions of reduced microcirculation. We investigated the influence of low-intensity laser irradiation by means of infrared thermography on skin blood circulation in diabetic patients with diabetic microangiopathy. RESEARCH DESIGN AND METHODS: Thirty consecutive patients with diabetic ulcers or gangrenes and elevated levels of glycosylated hemoglobin were randomized by blocks of two to receive either a single low-intensity laser irradiation with an energy density of 30 J/cm2 or a sham irradiation over both forefoot regions in a double-blind placebo-controlled clinical study. Skin blood circulation as indicated by temperature recordings over the forefoot region was detected by infrared thermography. RESULTS: After a single transcutaneous low-intensity laser irradiation, a statistically significant rise in skin temperature was noted (P < 0.001 by ANOVA for repeated measurements), whereas in the sham-irradiated control group, a slight but significant drop in temperature (P < 0.001) was found. Subsequently performed contrasts for comparison of measurements before and after irradiation revealed significant temperature increases at 20 min of irradiation time (P < 0.001), at the end of the irradiation (P < 0.001), and 15 min after stopping the irradiation (P < 0.001). In the sham-irradiated feet, the drop in local skin temperature was not significant at 20 min (P = 0.1), but reached significance at the end of the sham-irradiation procedure (P < 0.001) and 15 min after the end of sham irradiation (P < 0.001). CONCLUSIONS: The data from this first randomized double-blind placebo-controlled clinical trial demonstrate an increase in skin microcirculation due to athermic laser irradiation in patients with diabetic microangiopathy.

Analysis of Variance↗
PubMed1996

Spontaneous versus edrophonium-induced recovery from paralysis with mivacurium.

This study compared spontaneous with edrophonium-induced recovery of neuromuscular transmission (NMT) after mivacurium infusion. During nitrous oxide-narcotic-propofol anesthesia, the electromyogram (EMG) of the adductor pollicis (AP) was recorded and the movement of the first toe in response to stimulation of the posterior tibial nerve was noted. Mivacurium infusion was titrated to produce posttetanic count of 1-5 at the toe and absence of NMT at the AP. Thirty children were assigned to three groups on the basis of age. Edrophonium, 1 mg/kg, with atropine 10 micrograms/kg, was given after the mivacurium infusion when NMT of the AP was 1% or 10% of baseline. In the third group, spontaneous recovery was observed. Edrophonium given when NMT was 11% +/- 1% SEM produced the most rapid recovery, 7.5 +/- 0.6 min to a train-of-four (TOF) ratio (T4/T1) of 0.9 and the shortest interval from T4/T1 of 0.4-0.9, when residual block was likely to be underestimated, 4.8 +/- 0.6 min. Edrophonium given when block was greater produced recovery of the T4/T1 to 0.4 in 2.8 +/- 0.7 min, but the time from then to T4/T1 = 0.9 was 7.9 +/- 1.1 min, as long as during spontaneous recovery. Spontaneous recovery to T4/T1 = 0.9 occurred 12.9 +/- 0.7 min after the first measurable AP EMG. There was no significant relationship between duration of infusion, which ranged from 16 to 135 min, and time to appearance of AP EMG after the infusion, which averaged 3.1 +/- 0.5 min. We recommend that administration of edrophonium to induce reversal of mivacurium be delayed until two responses to a TOF stimuli are observed because this will produce the most rapid recovery and decrease the interval in which residual block may be underestimated.

Anesthesia Recovery Period↗
PubMed1993

[Behavior of various activity-controlled cardiac pacemakers in treadmill stress tests with variable slopes].

New activity pacemaker systems with the principle of sensing low-frequency acceleration in the anterior-posterior axis are currently under clinical evaluation. We compared the pacemaker system Relay, which represents this new generation of accelerometer controlled devices, with conventional activity systems sensing pressure and vibration. Ten pacemaker patients with implanted Activitrax, Sensolog or Relay pacemakers and 10 healthy volunteers with externally strapped-on pacemakers were studied. The aim was to evaluate the systems' ability to distinguish different workloads during graded treadmill testing with changes in speed and/or slope. The rate adaption of the new acceleration sensing pacemakers was found to be more adequate compared to vibration and pressure-sensing pacemakers when only the slope of the treadmill was varied. The acceleration-sensing pacemaker adjusted its rate according to the workload largely independent from the type of stress (n.s.). With the vibration and pressure-sensing pacemakers, however, significant differences (p < 0.05) were seen between rate adaption in the two stress test modes. The new generation of acceleration-sensing pacemakers has certain advantages over conventional vibration-sensitive systems in terms of a higher sensitivity to varying workloads and higher specificity to the type of exercise performed.

Adult↗
PubMed1992

Behavioral and neurochemical indices of barrel cortex-basal ganglia interaction.

Previous experiments from our laboratory have shown a wide variety of time-dependent lateralized changes in behavior and nigrostriatal function following unilateral manipulation of the mystacial vibrissae of rats. The present experiment investigated the effects of unilateral radiofrequency lesion of the cortical vibrissae representation (the barrel fields) in light of these results. We measured lateralized changes in behavior as well as tissue monoamines in neostriatum and substantia nigra, between 1 and 16 days post-lesion. Short-term asymmetries in exploratory behavior (thigmotactic scanning) and neostriatal serotonin metabolism that lasted up to day 6 were seen. In substantia nigra, time-related asymmetries in dopamine concentrations were found with higher ipsilateral values on day 3 and higher contralateral values on day 6. After day 6, the animals had recovered from these acute effects and thereafter, neostriatal dopamine metabolism became asymmetrical. Also during this time, they showed a directional bias in spontaneous and apomorphine-induced turning. Finally, neostriatal serotonin was bilaterally elevated on day 16. These results parallel some of the effects previously seen following unilateral removal of the vibrissae, indicating that the barrel cortex is a critical link in the functional interaction between the vibrissae and basal ganglia.

Animals↗
PubMed1989

Peroxisomal oxidation of pipecolic acid in the rat.

Postnuclear fractions from rat liver and kidney oxidize L-pipecolic acid, a by-product of lysine catabolism, in a hydrogen peroxide-producing reaction. This pipecolate oxidase2) activity is enhanced in preparations from animals treated with clofibrate and thyroxine, substances known to act as peroxisome proliferators and inducers of the peroxisomal fatty acid beta-oxidation. The enzymatic activity co-purified with the peroxisomal marker fatty acyl-CoA oxidase2) rather than with the mitochondrial marker glycerol-3-phosphate dehydrogenase2). Thus the degradation of L-pipecolic acid may start in the rat with a peroxisomal oxidase comparable to other hydrogen peroxide-producing oxidases found in peroxisomes. These findings provide indirect evidence that the marked hyperpipecolinaemia described in a group of human genetic disorders connected with peroxisomal defects such as Zellweger syndrome might be due to the absence of peroxisomal L-pipecolate oxidase.

Animals↗
PubMed1988

[Therapy resistance of amiodarone-induced hyperthyroidism].

The case of a 77-year-old patient who suffered from clinically severe and persistent hyperthyroidism induced by amiodarone is described. Amiodarone-associated hyperthyroidism is a rare (1-5%) but potentially severe complication. Its treatment presents a serious problem. The newer forms of treatment of this specific type of hyperthyroidism with prednisone and perchlorate are described. Under a combined therapy with thionamide drugs, prednisone and perchlorate euthyroidism could be achieved only after months. We propose a simple diagnostic procedure during amiodarone therapy based on the determination of basal ultrasensitive TSH enabling early recognition of amiodarone-associated hyperthyroidism. Thus, with well defined cardiac criteria for therapy with amiodarone as well as early assessment of thyroid dysfunction the incidence of this potentially severe complication can be reduced.

Aged↗
PubMed1986

[Traumatic myocardial infarct. Report of 3 cases].

Three patients aged 52, 22 and 29 years, without known previous heart disease, sustained acute myocardial infarction due to blunt chest trauma. A 52-year-old man without a history of heart disease sustained an acute non-transmural lateral myocardial infarction following blunt chest trauma during a sledging party. No coronary arteriography was performed. The clinical course during follow-up of 3 1/2 years was uncomplicated. A 22-year-old, previously asymptomatic man developed acute transmural anteroseptal infarction after a motor-cycle accident. Seven days later he died suddenly after an uncomplicated initial course. The autopsy demonstrated a complete rupture of the proximal left anterior descending artery with periarterial hemorrhage, compression of this artery by the hemorrhage and luminal thrombosis distal to the rupture. No sign of preexisting atherosclerotic coronary disease was found. A 29-year-old man admitted to the hospital after blunt chest trauma during a football game developed an acute transmural inferior infarction with an uncomplicated clinical course. Seven months later coronary arteriography demonstrated a 40% obstructive lesion of the right coronary artery, compatible with thrombosis and subsequent recanalization.

Accidents, Traffic↗
PubMed1984

[Noninvasive first-pass study of the heart with the short-lived radionuclide gold 195m].

The new shortlived radionuclide Aurum 195 m (T1/2: 30.5 sec) has been used for 1,596 first-pass examinations of 792 patients. During first-pass the same maximum count rates of an average of 300,000 cts/sec and after background subtraction the same enddiastolic counts over the left ventricle averaging 10,000 cts/sec can be achieved as with the previously used Tc-99 m pertechnetate injections. The short half-life and fast regeneration of Au-195 m within 3 minutes allow repeated, subsequent injections with significant reduction in radiation exposure. Half of the studies were done at rest and exercise, one third in two oblique projections, RAO and LAO. Examinations in two projections improve the information facilitating the localization of ischemic or infarcted LV-regions particularly with respect of septal and/or lateral extension. Strictly lateral dysfunction may sometimes be only recognizable in the second LAO-projection. The RAO-view best discriminates the extension along the anterior and infero-posterior wall.

Evaluation Studies as Topic↗
PubMed1983

Toxicological evaluation of cyclosporin A.

Toxicological studies in a variety of different animal species have shown that cyclosporin A (CS-A) is a unique immunosuppressant, since it does not cause myelotoxic, teratogenic, mutagenic, or carcinogenic effects. This is undoubtedly due to the fact CS-A produces its immunosuppressive effects by a specific action on T lymphocytes rather than by a cytotoxic mechanism. The incidence of acute inflammatory lesions was also not significantly higher in treated animals than in controls. Clear-cut organ toxicity only occurred in rats and cynomolgus monkeys, where at high doses nephro- and hepatotoxicity were observed.

Animals↗