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Featured researches published by O. Sauer.


Journal of Photochemistry and Photobiology B-biology | 1998

In vitro and in vivo porphyrin accumulation by C6 glioma cells after exposure to 5-aminolevulinic acid

Walter Stummer; Susanne Stocker; Alexander Novotny; Axel Heimann; O. Sauer; Oliver Kempski; Nikolaus Plesnila; Joachim Wietzorrek; H.-J. Reulen

Several malignant tissues synthesize endogenous porphyrins after exposure to 5-aminolevulinic acid (5-ALA). The present experiments have been designed to elucidate whether the C6 glioma cell, a model cell for human malignant glioma, similarly synthesizes porphyrins when exposed to 5-ALA, and whether specific synthesis occurs when C6 cells are inoculated into rat brains to form a tumor. In this situation the blood-brain barrier may interfere with 5-ALA availability, and spreading of porphyrins with edema outside the tumor may occur. Flow cytometry is used to determine the course of cell volume and porphyrin fluorescence intensities in cultured C6 cells which are incubated in 1 mM 5-ALA. For the induction of experimental brain tumors, 10(4) untreated C6 cells are inoculated into the brains of rats. After 9 days animals receive 100 mg 5-ALA/kg body weight. Brains are removed after 3, 6, or 9 h and frozen coronal sections obtained for H/E staining or fluorescence spectography. Cultured C6 cells show a linear increase of protoporphyrin IX fluorescence after exposure to 5-ALA, which begins to plateau after 85 min. Marked fluorescence is also observed in solid and infiltrating experimental tumor. However, faint fluorescence also occurs in normal tissue, basal pia, choroid plexus, and, more obviously, in white-matter tracts bordering the tumor (maximal distance: 1.5 +/- 0.7 mm). The observations demonstrate that C6 cells synthesize protoporphyrin IX after exposure to 5-ALA in vitro and in vivo. However, when utilizing 5-ALA for fluorescence detection or photodynamic therapy of brain tumors, attention should be paid to the possibility of protoporphyrin IX occurring outside the tumor.


BMC Neurology | 2005

Observations on comatose survivors of cardiopulmonary resuscitation with generalized myoclonus

Frank Thömke; J. J. Marx; O. Sauer; Thomas Hundsberger; Stefan Hägele; Jascha Wiechelt; Sacha L. Weilemann

BackgroundThere is only limited data on improvements of critical medical care is resulting in a better outcome of comatose survivors of cardiopulmonary resuscitation (CPR) with generalized myoclonus. There is also a paucity of data on the temporal dynamics of electroenephalographic (EEG) abnormalities in these patients.MethodsSerial EEG examinations were done in 50 comatose survivors of CPR with generalized myoclonus seen over an 8 years period.ResultsGeneralized myoclonus occurred within 24 hours after CPR. It was associated with burst-suppression EEG (n = 42), continuous generalized epileptiform discharges (n = 5), alpha-coma-EEG (n = 52), and low amplitude (10 μV <) recording (n = 1). Except in 3 patients, these EEG-patterns were followed by another of these always nonreactive patterns within one day, mainly alpha-coma-EEG (n = 10) and continuous generalized epileptiform discharges (n = 9). Serial recordings disclosed a variety of EEG-sequences composed of these EEG-patterns, finally leading to isoelectric or flat recordings. Forty-five patients died within 2 weeks, 5 patients survived and remained in a permanent vegetative state.ConclusionGeneralized myoclonus in comatose survivors of CPR still implies a poor outcome despite advances in critical care medicine. Anticonvulsive drugs are usually ineffective. All postanoxic EEG-patterns are transient and followed by a variety of EEG sequences composed of different EEG patterns, each of which is recognized as an unfavourable sign. Different EEG-patterns in anoxic encephalopathy may reflect different forms of neocortical dysfunction, which occur at different stages of a dynamic process finally leading to severe neuronal loss.


Clinical Toxicology | 2010

Escitalopram causes fewer seizures in human overdose than citalopram.

Zeynep Yilmaz; Alessandro Ceschi; Christine Rauber-Lüthy; O. Sauer; Uwe Stedtler; Dagmar Prasa; Carola Seidel; Elisabeth Hackl; Petra Hoffmann-Walbeck; Gabriela Gerber-Zupan; Kathrin Bauer; Hugo Kupferschmidt; G.A. Kullak-Ublick; Martin F. Wilks

Context. Seizures are a recognized complication of acute overdose with the racemic (1:1 ratio of R- and S-enantiomers) selective serotonin reuptake inhibitor antidepressant citalopram. Objective. We tested the hypothesis that escitalopram (the therapeutically active S‐enantiomer of citalopram) causes fewer seizures in overdose than citalopram at comparable doses of the S-enantiomer. Methods. Multicenter retrospective review of cases with citalopram and escitalopram overdose reported to German, Austrian, and Swiss Poisons Centers between 1997 and 2006. Results. 316 citalopram and 63 escitalopram cases were analyzed. Somnolence, nausea, vomiting, tachycardia, QT prolongation, and tremor occurred with similar frequency in both groups. There was a striking difference in the frequency of single and multiple seizures: 43 cases (13.5%) in the citalopram group and 1 case (1.6%) with a single seizure in the escitalopram group (p = 0.0065). Discussion and conclusions. At comparable ingested doses of the S-enantiomer, the symptom profile for citalopram and escitalopram intoxications is similar except for seizures that occur more frequently in citalopram than in escitalopram poisoning.


Lung | 2006

An update on interventional lung assist devices and their role in acute respiratory distress syndrome.

Marc-Alexander von Mach; J. Kaes; Babatunde Omogbehin; Ingo Sagoschen; Jascha Wiechelt; Kristina Kaiser; O. Sauer; L. S. Weilemann

In recent years, pumpless arteriovenous systems for extracorporeal gas exchange have become a new therapeutic option for the treatment of patients suffering from acute respiratory failure. Experiences with the pumpless extracorporeal membrane lung in animal experiments and in patients with adult respiratory distress syndrome published in the current literature are reviewed. In addition this article presents a case of varicella pneumonia with persistent hypoxemia and hypercapnia under mechanical ventilation that showed a significant improvement with treatment with a pumpless extracorporeal lung assist using an arteriovenous shunt for eight days. The patient made a complete recovery. This is the first report of a patient with a life-threatening varicella pneumonia successfully treated with pumpless extracorporeal lung assist device. This review provides an update on interventional lung assist devices and a critical discussion of their advantages and limitations.


Experimental and Clinical Endocrinology & Diabetes | 2004

Experiences of a poison center with metformin-associated lactic acidosis.

Ma von Mach; O. Sauer; L. Sacha Weilemann


Experimental and Clinical Endocrinology & Diabetes | 2004

Metformin-associated lactic acidosis: a case report and analysis of a poison centre database

Ma von Mach; O. Sauer; L. S. Weilemann


Intensivmedizin Und Notfallmedizin | 1997

Psychogene Amphetamine (,,Ecstasy``)

O. Sauer; L. S. Weilemann


Deutsche Medizinische Wochenschrift | 2003

[Fulminant pulmonary edema in falciparum malaria [corrected]].

M.-A. Von Mach; T. Hansen; W. Ehrenthal; O. Sauer; L. S. Weilemann


Intensivmedizin Und Notfallmedizin | 2005

Klinischer Stellenwert von Monointoxikationen mit Ibuprofen, Diclofenac und Metamizol

J. Kaes; M.-A. von Mach; I. Weilemann; J. Wiechelt; Michael Lauterbach; A. Eich; O. Sauer; L. S. Weilemann


Intensivmedizin Und Notfallmedizin | 2004

Lethal outcome of gas gangrene sepsis in a patient with pancytopenia?A case report

J. Kaes; Marc A von Mach; Valentine O Wagner; O. Sauer; Michael Lauterbach; J. Wiechelt; L. S. Weilemann

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