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Biomedical subjects

E Schindler

Publications and source records attributed to E Schindler.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Cocaine-induced acute CNS diseases].

Drug-associated/-induced neurological complications are well known in the literature. Cocaine is of major interest due to its widespread use. On the basis of a case report, we discuss the broad spectrum of medical and, in particular, neurological complications. The risk of cerebrovascular damage and epileptic seizures is indicated. The pathophysiological mechanisms of cerebrovascular complications are not well understood.

Brain Damage, Chronic↗
PubMed1999

Virchow-Robin spaces in childhood migraine.

Virchow-Robin spaces (VRS) are pia-lined extensions of the subarachnoid space which surround penetrating arteries as they enter the brain on its surface. Using high-resolution MRI, which shows small penetrating arteries, we studied a possible association of accentuated VRS in children with tension-type headache (TTH) or migraine. We studied 58 children aged 3-14 years (mean 10.8 years) with a clinical diagnosis of migraine (31) or TTH (27), who underwent cerebral MRI, and 30 headache-free patients of the same age (mean 10.2 years) and 30 adult migraineurs with postpubertal onset of symptoms, who served as controls. The images were reviewed for structural abnormalities in the regions of the small penetrating arteries. Accentuated VRS were found in 61% of the children with migrainous headaches and in 22% of children of those with TTH. Prominent VRS were seen in 27% of the control children and in only 13% of the adults. Small infarcts and gliosis were rare in children with or without headache, but were seen in 30% of the adult migraineurs. Our findings show that accentuated VRS are significantly more common in children with migraine than in those with TTH or headache-free controls. Detection of accentuated VRS may therefore enhance differential diagnosis of primary headaches in children, contributing to an improvement in management.

Adolescent↗
PubMed1999

Effects of low-dose dopexamine on splanchnic oxygenation during major abdominal surgery.

OBJECTIVE: To study the influence of low-dose dopexamine on splanchnic oxygenation during major abdominal surgery. DESIGN: Prospective, randomized, placebo-controlled study. SETTING: University hospital. PATIENTS: Eighteen adult patients undergoing elective major abdominal surgery. INTERVENTIONS: The patients received either dopexamine at 1 microg/kg/min (group A, n = 9) or 0.90% saline as control (group B, n = 9). MEASUREMENTS AND RESULTS: To assess the splanchnic oxygenation, intestinal tissue PO2 (PtissO2) and gastric intramucosal Pco2 (PmucCO2) were measured, and the PCO2 gap (PmucCO2 - PaCO2) was calculated at baseline (T1) and after an infusion period of 60 mins (T2). There was no difference between the groups in the global oxygen transport parameters. Low-dose dopexamine increases PtissO2 on the serosal side of the small bowel (deltaPtissO2, 17+/-24 mm Hg in group A vs. -5+/-10 in group B). The changes in PtissO2 at the serosal side of the colon after dopexamine demonstrated a nonsignificant increase (deltaPtissO2, 7+/-11 mm Hg in group A vs. -11+/-23 mm Hg in group B). In both groups, the Pco2 gap (group A, 6+/-7 mm Hg [T1] and 5+/-6 mm Hg [T2], vs. group B, 9+/-10 mm Hg [T1] and 12+/-10 mm Hg [T2]) remained unchanged compared with the baseline. CONCLUSION: It is concluded that low-dose dopexamine improves PtissO2 at the serosal side of the gut, preferably at the small bowel. However, low-dose dopexamine did not improve gastric PmucCO2.

Abdomen↗
PubMed1998

Intraoperative computed tomography guided neuronavigation: concepts, efficiency, and work flow.

Image-guided surgery is currently considered to be of undisputed value in microsurgical and endoscopical neurosurgery, but one of its major drawbacks is the degradation of accuracy during frameless stereotactic neuronavigation due to brain and/or lesion shift. A computed tomography (CT) scanner system (Philips Tomoscan M) developed for the operating room was connected to a pointer device navigation system for image-guided surgery (Philips EasyGuide system) in order to provide an integrated solution to this problem, and the advantages of this combination were evaluated in 20 cases (15 microsurgical and 5 endoscopic). The integration of the scanner into the operating room setup was successful in all procedures. The patients were positioned on a specially developed scanner table, which permitted movement to a scanning position then back to the operating position at any time during surgery. Contrast-enhanced preoperative CCTs performed following positioning and draping were of high quality in all cases, because a radiolucent head fixation technique was used. The accuracy achieved with this combination was significantly better (1.6:1.22.2). The overall concept is one of working in a closed system where everything is done in the same room, and the efficiency of this is clearly proven in different ways. The most important fact is the time saved in the overall treatment process (about 55 h for one operating room over a 6-month period). The combination of an intraoperative CCT scanner with the pointer device neuronavigation system permits not only the intraoperative control of resection of brain tumors, but also (in about 20% of cases) the identification of otherwise invisible residual tumor tissue by intraoperative update of the neuronavigation data set. Additionally, an image update solves the problem of intraoperative brain and/or tumor shifts during image-guided resection. Having the option of making an intraoperative quality check at any time leads to significantly increased efficiency, improves the operating work flow because of the closed-system concept, and offers an integrated solution for improved patient work flow and clinical outcome.

Brain Neoplasms↗
PubMed1998

[Perfusion and metabolism of liver and splanchnic nerve area under sevoflurane anesthesia].

In common with other halogenated volatile anaesthetics, sevoflurane causes a dose-related cardiovascular depression and therefore the affection of blood flow of different organ systems is suggested. So far known, sevoflurane is not different compared to isoflurane in affecting liver and splanchnic blood flow. Concluded from former published studies there was no case of hepatic toxicity of sevoflurane been published so that this substance can be used in patients with reduced hepatic function. The primary organic metabolite of sevoflurane is hexafluorisopropanol (HFIP), which is readily and rapidly conjugated with glucuronic acid. No reactive intermediates are formed and HFIP appears to be an unlikely compound to form liver protein adducts. For this reasons sevoflurane "hepatitis" is not expected. Like most other inhalation agents sevoflurane increase the neuromuscular blockade after treatment with muscle relaxants in anaesthesia. The MAC values of Sevoflurane where reduced after the application of nitrous oxide, benzodiazepines and opiates. From human studies we know that chronic drug therapy with isoniazid induces the metabolism of sevoflurane, enflurane and isoflurane, markedly increasing peak plasma fluoride concentrations. However, barbiturates as well as phenytoin do not influence the metabolism of sevoflurane because these agents do not induce the major hepatic defluorinating enzyme cytochrome P450 2E1. Obesity, untreated diabetes mellitus and alcohol abuse increase the hepatic content and activity of cytochrome P450 2E1 and therefore enhanced anaesthetic defluorination is to be suspected. Until now, there are no studies about sevoflurane anaesthesia in patients after liver transplantation but the extremely low hepatotoxic potential as compared to isoflurane provides no argument to avoid this substance for anesthesia in liver transplanted patients.

Anesthetics, Inhalation↗
PubMed1998

[Xenon-CT and perfusion MRI in the diagnosis of cerebral gliomas].

Within certain limits the vascularity of cerebral gliomas correlates with dysplasia. Xenon CT and perfusion MRI can be used to investigate tumor vascularity. Using an optimized wash in/out protocol with inhalation of 30% xenon gas, xenon CT was performed and regional cerebral blood flow (rCBF) and blood/tissue partition coefficient (lambda) calculated. Furthermore, perfusion MRI was performed using a dynamic T2*w EPI sequence with intravenous administration of Gd-DTPA. The relative regional cerebral blood volume, arrival time, time to peak and mean transit time were calculated. Both modalities were used in patients with supratentorial gliomas and compared with conventional contrast-enhanced MRI (ceMRI). Calculation of regional cerebral blood flow, as compared to ceMRI, did not contribute to the diagnostic approach of tumor dysplasia. Tumour vascularity was better estimated by measurement of lambda. Measurement of relative regional cerebral blood volume also correlated with tumor vascularity. Mainly the possibility of direct quantification of the Xe-CT data was advantagenous compared to perfusion MRI, and the XeCT data could be interpreted more clearly. Further upgrades of the technical equipment of MR as well as upgrades of available software will increase the applicability of perfusion MRI. However, both modalities offer a more precise investigation of tumor vascularization compared to ceMRI since potential dysplastic alteration may be detected earlier, which will be advantageous for planning bioptical approach of such tumours.

Astrocytoma↗
PubMed1998

An assessment of selective cerebral perfusion via the innominate artery in aortic arch replacement.

Maintaining an adequate cerebral oxygen supply is a serious problem in aortic arch surgery. Deep hypothermic circulatory arrest is the most common method used for cerebral protection, but guarantees only a time-limited safety period. Based on experimental investigations, we applied selective cerebral perfusion via the innominate artery alone with only moderate hypothermia (28 degrees C) and without circulatory arrest in 25 consecutive patients undergoing surgical treatment of an aneurysm (n = 10) or acute type-A dissection (n = 15) involving the aortic valve and arch. In every case a test perfusion was carried out to assess whether the cerebral perfusion achieved would be adequate for the whole operation. In no case was the perfusion inadequate. As a new perioperative monitoring system, we used computer-aided topographical electroencephalometry (CATEEM). There were 18 male and 7 female patients, their age was 47.0 +/- 15.1 years (mean +/- SD). Mean time periods were 155.1 +/- 37.3 min for aortic cross-clamping, and 69.3 +/- 35 min for selective cerebral perfusion. Postoperatively, two patients (8%) revealed a temporary left-sided hemiparesis, and 4 patients (16%) died within 30 days. The overall mortality rate was 16% in a follow-up period of 24.2 +/- 9.5 months. In this small group the CATEEM monitoring enabled an intraoperative selection of patients with sufficient bihemispheric collateral circulation and therefore suitable for simple innominate artery perfusion.

Acute Disease↗
PubMed1998

Humanized anti-L-selectin monoclonal antibody DREG200 therapy in acute thromboembolic stroke.

Strategies directed against activated neutrophils have reduced ischemia-induced brain injury. However, therapies targeted specially against the neutrophil adhesion protein L-selectin have not yet been examined in stroke. This study therefore examined the effects of a monoclonal antibody directed against L-selectin in a rabbit model of thromboembolic stroke with (n = 16) or without (n = 10) concomitant t-PA therapy. Rabbits received either the humanized monoclonal antibody DREG200 directed against the L-selectin receptor or humanized control monoclonal antibody HuDREG55 which does not bind to rabbit L-selectin in addition to t-PA therapy (n = 8, each group). HuDREG200 (2 mg kg-1 i.v.) was given as a bolus 3 h following clot embolization, followed immediately by a 2 h intravenous infusion of t-PA (6.3 mg kg-1. Without t-PA therapy rabbits received HuDREG200 (2 mgkg-1, i.v.; n = 5) or HuDREG55 (n = 5) 1 h following clot embolization. The group receiving HuDREG200 in addition to t-PA demonstrated a moderate improvement in brain infarct size (8.4 +/- 2.4 vs. 13.5 +/- 3.5, %hemisphere, mean +/- sem), ICP (final reading 10.0 +/- 1.6 vs. 12.4 +/- 3.0 torr) and restoration in regional cerebral blood flow (30.2 +/- 7.8 vs. 21.6 +/- 10.9 cc 100 g-1 min-1) when compared to t-PA therapy alone although statistical significance was not achieved. No efficacy was demonstrated in the group receiving HUDREG200 without concomitant t-PA therapy. The results suggest the addition of a humanized anti-L-selectin monoclonal antibody HuDREG200 in combination with t-PA may further improve outcome in acute thromboembolic stroke, although future studies are necessary to support these findings.

Acute Disease↗
PubMed1998

Modulation of somatosensory evoked potentials under various concentrations of desflurane with and without nitrous oxide.

Continuous measurement of somatosensory evoked potentials (SEP) by means of characteristic changes in the signal pattern makes it possible to identify cerebral or spinal cord ischemia during critical phases of the operative procedure. A correct interpretation of the measurements is only possible, however, if the influence of drugs acting on the central nervous system is known. The authors were able to show that inhaled anesthetics have an impact on latencies and response amplitudes. This study examined the influence of various concentrations of desflurane on the conduction of SEP of the Median nerve. In addition, the authors determined how the supplementation of nitrous oxide (N2O) influences the stimulus response of the medianus nerve's SEP. Desflurane has been shown to produce dose-dependent increases in SEP latency (data in part for latency N2O: 0.5 minimum alveolar concentration [MAC] = 20.8 +/- 0.9; 1.5 MAC = 22.2 +/- 1.5; 1.5 MAC/N2O= 23.8 +/- 1.5) and decreases in amplitude, whereas cervically recorded subcortical SEP components are minimally influenced by desflurane. When nitrous oxide is added, there were marked reductions in amplitude (p<0.01) of the cortical stimulus response (1.5 MAC = 2.4 +/- 0.9; 1.5 MAC/N2O = 1.1 +/- 1). It can therefore be recommended that supplementation with N2O should be avoided in the presence of low initial amplitudes. Based on the study's results, the use of desflurane (up to 1.0 MAC) seems to be compatible with intraoperative monitoring of median somatosensory evoked potentials.

Anesthesia, Inhalation↗
PubMed1997

[A protocol for the assessment of patients with coma of unknown origin].

OBJECTIVE: Evaluation of the applicability of a protocol designed for the quick and efficient management of patients with coma of unknown origin (CUO). METHODS: Every patient admitted to our Emergency Department with the diagnosis of CUO was evaluated with our diagnostic protocol. The first diagnostic steps included evaluation of the hemodynamic and respiratory situation, Glasgow Coma Scale, basic neurologic and clinical examination, as well as blood withdrawal, for analysis of metabolic and toxicologic parameters. If indicated, cranial computer tomography (CCT) and/or lumbar puncture were performed. RESULTS: Within the study period from 1. 1. 1995 until 30. 9. 1996, 122 patients (65 males, median age 50 years, 25 and 75 percentile: 33; 69) were included. Blood analysis and the toxicological screening were diagnostic effective in 66 patients, clinical examination and body temperature in one case each, CCT in 50 patients and lumbar puncture in 2 patients. By the use of this diagnostic protocol 51 neurologic, 38 toxicologic, 28 metabolic and 2 infectious causes of coma were diagnosed (98%). Etiology of 2 of the comas remained unclear. CONCLUSION: By using our protocol, 98% of the causes of CUO were clarified. The main causes of coma were of neurological, toxicological and metabolic origin. CCT and the blood analysis were the most important procedures leading to a final diagnosis.

Adult↗
PubMed1997

[Urgent diagnostic steps in acute manifestation of intraspinal processes].

Immediate diagnostic clarification is required in patients who develop acute or subacute symptoms suggestive of an intraspinal lesion. In case of symptoms indicating a monoradicular lesion a spinal CT investigation is mostly sufficient. Since polyradicular syndromes are often due to inflammation, examination of the cerebrospinal fluid is the most important diagnostic measure. However, in case of symptoms suggestive of intramedullary lesions, spinal MRT is by far the most effective diagnostic procedure. In patients with symptoms suggestive of a lesion of the cauda equina spinal CT is sufficient in most cases as a first measure, particularly if the lesion can be precisely localized by clinical examination. The decision as to which diagnostic method should be performed first is relevant mainly because of the limited availability of MRT examinations within the daily clinical routine. MRT should thus be used selectively in patients with lesions that cannot be identified by alternative diagnostic methods.

Diagnosis, Differential↗