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Biomedical subjects

G Schneider

Publications and source records attributed to G Schneider.

At least 19 recordsLinked to original sources
PubMed2007

Teletherapeutic drug administration by long distance closed-loop control of propofol.

BACKGROUND: The objective of this pilot study was to investigate the feasibility of an EEG-controlled closed-loop administration of propofol over a long distance of about 200 km. METHODS: We performed a teletherapeutic propofol infusion during total intravenous anaesthesia with propofol in 11 patients undergoing general surgery. The teletherapeutic system consisted of a computer at the patient site in Munich and a computer at the control site in Erlangen, which were connected via the internet through a virtual private network. The patient's EEG signal was sent to the control site computer, where the median frequency (MEF) of the EEG power spectrum was calculated. The propofol infusion, determined by a model-based adaptive feedback algorithm to maintain a MEF of 1.5 to 2 Hz, was sent to the patient site computer connected to the infusion pump. The quality of the control was assessed by the performance error defined as the percentage deviation of the measured MEF from the set point and the necessity of interventions by the anaesthetist at the patient site. RESULTS: During closed-loop administration of propofol [83 (52) min] the median performance error of the system was - 4.6 (4.4)% and the median absolute performance error was 18.8 (5.7)%. From a total number of 10 905 transmitted EEG epochs, there were five epochs with transmission errors, without further consequences for drug control. In one patient, teletherapy was stopped because the internet connection was interrupted. CONCLUSIONS: Teletherapeutic drug administration could be realized over a longer distance. Further studies have to investigate the practicability and safety of teletherapeutic drug control in anaesthesia.

Adolescent↗
PubMed2006

First steps towards effective methods in exploiting high-throughput technologies for the determination of human protein structures of high biomedical value.

The EC 'Structural Proteomics In Europe' contract is aimed specifically at the atomic resolution structure determination of human protein targets closely linked to health, with a focus on cancer (kinesins, kinases, proteins from the ubiquitin pathway), neurological development and neurodegenerative diseases and immune recognition. Despite the challenging nature of the analysis of such targets, approximately 170 structures have been determined to date. Here, the impact of high-throughput technologies, such as parallel expression of multiple constructs, the use of standardized refolding protocols and optimized crystallization screens or the use of mass spectrometry to assist sample preparation, on the structural biology of mammalian protein targets is illustrated through selected examples.

Animals↗
PubMed2006

Eukaryotic expression: developments for structural proteomics.

The production of sufficient quantities of protein is an essential prelude to a structure determination, but for many viral and human proteins this cannot be achieved using prokaryotic expression systems. Groups in the Structural Proteomics In Europe (SPINE) consortium have developed and implemented high-throughput (HTP) methodologies for cloning, expression screening and protein production in eukaryotic systems. Studies focused on three systems: yeast (Pichia pastoris and Saccharomyces cerevisiae), baculovirus-infected insect cells and transient expression in mammalian cells. Suitable vectors for HTP cloning are described and results from their use in expression screening and protein-production pipelines are reported. Strategies for co-expression, selenomethionine labelling (in all three eukaryotic systems) and control of glycosylation (for secreted proteins in mammalian cells) are assessed.

Animals↗
PubMed2006

Application of the use of high-throughput technologies to the determination of protein structures of bacterial and viral pathogens.

The Structural Proteomics In Europe (SPINE) programme is aimed at the development and implementation of high-throughput technologies for the efficient structure determination of proteins of biomedical importance, such as those of bacterial and viral pathogens linked to human health. Despite the challenging nature of some of these targets, 175 novel pathogen protein structures (approximately 220 including complexes) have been determined to date. Here the impact of several technologies on the structural determination of proteins from human pathogens is illustrated with selected examples, including the parallel expression of multiple constructs, the use of standardized refolding protocols and optimized crystallization screens.

Animals↗
PubMed2006

Local and systemic effects on blood lactate concentration during exercise with small and large muscle groups.

To evaluate the relationship between lactate release and [lac](art) and to investigate the influence of the catecholamines on the lactate release, 14 healthy men [age 25+/-3 (SE) year] were studied by superimposing cycle on forearm exercise, both at 65% of their maximal power reached in respective incremental tests. Handgrip exercise was performed for 30 min at 65% of peak power. In addition, between the tenth and the 22nd minute, cycling with the same intensity was superimposed. The increase in venous lactate concentration ([lac](ven)) (rest: 1.3+/-0.4 mmol.l(-1); 3rd min: 3.9+/-0.8 mmol.l(-1)) begins with the forearm exercise, whereas arterial lactate concentration ([lac](art)) remains almost unchanged. Once cycling has been added to forearm exercise (COMB), [lac](art) increases with a concomitant increase in [lac](ven) (12th min: [lac](art), 3.2+/-1.3 mmol.l(-1); [lac](ven), 5.7+/-2.2 mmol.l(-1)). A correlation between oxygen tension (P(v)O(2)) and [lac](ven) cannot be detected. There is a significant correlation between [lac](art) and norepinephrine ([NE]) (y=0.25x+1.2; r=0.815; p<0.01) but no correlation between lactate release and epinephrine ([EPI]) at moderate intensity. Our main conclusion is that lactate release from exercising muscles at moderate intensities is neither dependent on P(v)O(2) nor on [EPI] in the blood.

Adult↗
PubMed2006

Bicuspid aortic valve: evaluation of the ability to participate in competitive sports: case reports of two soccer players.

UNLABELLED: Two competitive soccer players aged 23 and 17 years with known bicuspid aortic valve presented for sports-medical pre-participation screening. Both athletes were well trained and had a maximal oxygen uptake of 61 and 60 ml/min/kg, respectively. Echocardiography of the first athlete revealed an eccentric hypertrophy of the left ventricle (end-diastolic diameter 58-59 mm, septal and posterior myocardial wall thickness 12-13 mm) with good systolic and diastolic function and a functional bicuspid aortic valve with mild regurgitation. In the second athlete, echocardiography showed a bicuspid aortic valve with moderate regurgitation and a relative stenosis, a hypertrophied left ventricle (end-diastolic diameter 62-63 mm, myocardial wall thickness 13-16 mm) and dilation of the ascending aorta of 46 mm, which was confirmed by magnetic resonance imaging. According to international guidelines, the first athlete was allowed to participate in competitive soccer. Nevertheless, regular cardiologic examinations in intervals of 6 months were recommended. In the second case, the athlete was not allowed to take part in competitive sports due to the extended ecstasy of the ascending aorta and the concomitant risk of an aortic rupture. In addition, the left ventricular hypertrophy has to be considered as pathologic. Therefore, the athlete was only allowed to exercise in recreational sports with low and easily controllable intensities. CONCLUSION: In athletes with bicuspid aortic valve, besides the evaluation of the aortic valve, physiologic adaptations of the heart have to be differentiated from pathological changes. Furthermore, the aorta deserves special attention, because in the case of a (probably genetically determined) dilated ascending aorta, an elevated risk for aortic rupture is present during intensive and competitive exercise. A general judgement in athletes with bicuspid aortic valves on their ability to participate in competitive sports is, therefore, not possible.

Adolescent↗
PubMed2006

Two infants with life-threatening diffuse neonatal hemangiomatosis treated with cyclophosphamide.

Diffuse neonatal hemangiomatosis (DNH) is a rare, frequently fatal disorder characterized by multiple cutaneous and visceral hemangiomas. Complications include high-output cardiac failure, hemorrhage, hepatic failure, and consumption coagulopathy. We present two cases of neonates with DNH. We prescribed cyclophosphamide after failure of corticosteroids. Cyclophosphamide induced a fast regression of the lesions with no side effects in both infants. We were able to stop treatment after 3-4 courses of cyclophosphamide in both infants because of the excellent response. Cyclophosphamide seems to be a safe and effective treatment in patients suffering from life-threatening DNH unresponsive to corticosteroids.

Adrenal Cortex Hormones↗
PubMed2006

[Clinical classification of chronic pruritus. Interdisciplinary consensus proposal for a diagnostic algorithm].

Chronic pruritus is a frequent symptom in dermatology caused by a variety of dermatologic, neurologic and other systemic diseases. For adequate, economically-appropriate medical care of patients with chronic pruritus, a clinical classification of pruritus which also serves as a diagnostic algorithm is necessary. Currently suggested classifications are etiologic and not helpful in daily clinical routine. The proposed clinical classification is oriented at the clinical appearance of the patients and differentiates between disorders with or without primary or secondary skin lesions.

Algorithms↗
PubMed2006

[Innovative imaging in urology: fascination and future. Yesterday, today, and tomorrow].

In contrast to other countries (e.g., USA) the German urologist routinely utilizes imaging in order to evaluate urological disorders. Ultrasound as a basic tool has acquired importance similar to the physical examination or the patient history. Because of its minimal invasiveness and low cost, it is increasingly utilized as a first-line exam.In correlation with the patient history and laboratory data more invasive imaging studies are performed and in unclear cases or in the preoperative work-up more extensive imaging procedures like computed tomography (CT) or magnetic resonance imaging (MRI) are utilized. Even in emergency situations the urologist is able to guide interventions under ultrasound or conventional X-ray guidance (e.g., percutaneous drainage of dilated kidney), which resulted in a much lower complication rate of the various procedures. In those cases in which ultrasound is technically infeasible or in unclear cases CT and MRI are used as problem-solving procedures and are able to give the correct diagnosis in a large percentage of cases.After a brief historical overview, newer modalities and innovative techniques are explored and presented. Assuming that these innovative approaches lead to more accurate diagnosis and staging of various neoplastic and nonneoplastic conditions, treatment can be performed in earlier stages of diseases and better stage-adapted treatment can be offered to the patients.

Diagnostic Imaging↗
PubMed2006

[Radiological examination of the hip. Analysis of standard projections].

Plain radiography of the hip joint is the imaging modality of first choice. The standard projections are an anteroposterior view of the whole pelvis and a lateral view of the involved hip. Depending on the suspected pathology, different lateral projections are used such as the Lauenstein view, a false profile view, or a lateral cross-table view. Additional projections may be helpful in special indications. For correct analysis and interpretation, the radiographs need to be checked for adequate orientation and exposure. The orthopedic surgeon has to be familiar with the imaging technique of each radiograph and its normal appearance in order to assess the orientation of the pelvis during exposure and to detect even subtle pathology or changes in orientation of the acetabulum or proximal femur.

Arthrography↗
PubMed2006

[Magnetic resonance tomography and arthrography of the hip joint].

Plain film radiographs represent the imaging of choice for the initial evaluation of pathologies of the hip. However, many lesions of the joint itself and surrounding soft tissues are often not visualized by conventional radiographs. Magnetic resonance imaging (MRI) demonstrates most of these pathologies with high sensitivity and specificity. For further assessment of intra-articular lesions such as labral tears, hyaline cartilage lesions, rupture of the ligamentum teres, and loose bodies, direct MR arthrography after intra-articular administration of contrast medium may be indicated. This article summarizes the technical aspects and the most important indications for MRI and MR arthrography of the hip in correlation with typical imaging findings of the most frequent pathologies.

Arthrography↗
PubMed2006

Caudal regression sequence: vascular origin?

Caudal regression sequence (CRS) is a rare congenital defect of the lower spinal segments and the neural tube. Motor symptoms as well as neurological deficits and loss of bladder and bowel function are usually present. CRS is also associated with anomalies in other systems such as the gastrointestinal and genitourinary tract. Etiology and pathogenesis are poorly understood.A newborn presented with anomalies of the spinal column (lumbosacral) with absence/hypoplasia of the 12th thoracic and first lumbar vertebral anomaly body. Bladder and bowel initially were functional. MR-angiography exhibited an anomaly of the unpaired vessels originating from the aorta, a likely relict of a persisting vitelline artery. These findings indicate a potential vascular genesis of CRS, much as in sirenomelia.

Abnormalities, Multiple↗
PubMed2006

Psychological factors in prurigo nodularis in comparison with psoriasis vulgaris: results of a case-control study.

BACKGROUND: It has been suggested that psychological factors such as repressing anger and altruistic interpersonal behaviour may play a role in the aetiology of chronic itching in prurigo nodularis (PN). Whether these issues are specific for PN or are also common in other chronic skin diseases, e.g. psoriasis, has not been investigated until now. OBJECTIVES: To investigate psychosomatic problem areas and psychiatric comorbidity in patients with PN in comparison with patients with psoriasis. METHODS: Ninety-four patients with PN and 91 patients with psoriasis were administered the Hospital Anxiety and Depression Scale, Toronto Alexithymia Scale, State-Trait Anger Expression Inventory, Inventory of Interpersonal Problems, Screening for Somatoform Disorders and the Whiteley Index for hypochondriasis. RESULTS: After Bonferroni post hoc adjustment, the metrical scales demonstrated no significant differences between patients with PN and those with psoriasis. There was only a tendency to less 'anger-out' and to less autocratic/dominant and more insecure/submissive behaviour in the patients with PN. Patients with PN were, in general, comparable with those with psoriasis with regard to alexithymia, somatization symptoms, hypochondriasis, anxiety and depression, with 18% cases of anxiety and 22% cases of depression. CONCLUSIONS: The hypotheses formulated in the literature on the specific aetiology of PN could not be proven for the majority of patients with PN in our study. Concerning their psychopathology, patients with PN were comparable with those with psoriasis. Therefore the clinical management of PN should include psychosomatic assessment.

Adult↗
PubMed2006

Psychosomatic cofactors and psychiatric comorbidity in patients with chronic itch.

BACKGROUND: While psychosomatic factors may be involved in eliciting as well as coping with chronic itch, psychiatric comorbidity often goes unrecognized in dermatological patients. AIM: To record psychiatric illness, psychiatric and psychotherapeutic pretreatment, and psychotherapy indication in dermatology inpatients with pruritus. METHODS: A consecutive sample of 109 dermatology inpatients with the symptom of pruritus were examined by interviews with consecutive ratings by experts (using psychiatric ICD-10 diagnoses, the Global Assessment of Functioning Scale and the Impairment Score) and self-assessment using the the Eppendorf Itch Questionnaire. RESULTS: In > 70% of the pruritus patients, 1-6 psychiatric diagnoses could be demonstrated. In > 60%, psychotherapeutic or psychiatric treatment was recommended. In contrast, almost 90% of the patients had had no previous psychotherapeutic experience. CONCLUSION: As psychiatric comorbidity in dermatology inpatients suffering from chronic itch is high, dermatology departments should aim for an improvement of their psychosomatic consultation and liaison services.

Adult↗
PubMed2005

Detection and assessment of near-zero delays in neuronal spiking activity.

Cross-correlation histograms (CCHs) have been widely used to study the temporal relationship between pairwise recordings of neuronal signals. One interesting parameter of a CCH is the time position of the central peak which indicates delays between signals. In order to study the potential relevance of these delays which can be as small as 1 ms, it is necessary to measure them with high precision. We present a method for the estimation of the central peak's position that is based on fitting a cosine function to the CCH and show that the precision of this estimate can be tracked analytically. We validate the resulting formula by simulations and by the analysis of a sample dataset obtained from cat visual cortex. The results indicate that the time position of the center peak can be estimated with submillisecond precision. The formula allows one also to develop a test of statistical significance for differences between two sets of measurements.

Algorithms↗
PubMed2005

Concurrent recording of AEP, SSEP and EEG parameters during anaesthesia: a factor analysis.

BACKGROUND: Spontaneous EEG, mid-latency auditory evoked potentials (AEP) and somatosensory evoked potentials (SSEP) have been used to monitor anaesthesia. This poses the question as to whether or not EEG, AEP and SSEP vary in parallel with varying conditions during surgical anaesthesia. METHODS: A total of 81 variables (31 EEG, 22 SSEP, 28 AEP) were simultaneously recorded in 48 surgical patients during anaesthesia. A total of 307 cases of the 81 variables in stable anaesthetic states were recorded. A factor analysis was performed for this data set. RESULTS: Sixteen variables were excluded because of multicollinearity. We extracted 13 factors with eigenvalues >1, representing 78.3% of the total variance, from the remaining 65 x 307 matrix. The first three factors represented 12%, 11% and 10% of the total variance. Factor 1 had only significant loadings from EEG variables, factor 2 only significant loadings from AEP variables and factor 3 only significant loadings from SSEP variables. CONCLUSION: EEG, AEP and SSEP measure different aspects of neural processing during anaesthesia. This gives rise to the hypothesis that simultaneous monitoring of these quantities may give additional information compared with the monitoring of each quantity alone.

Anesthesia, General↗
PubMed2005

[Pathogenesis of the ductal pancreatic adenocarcinoma: implications for future therapies?].

Despite the advances in the knowledge of the molecular pathogenesis, pancreatic cancer remains a devastating disease with an 5-year survival rate below 5%. Current therapeutic approaches are not successful in respect to overall survival. There is a need to transfer the knowledge of basic science to new therapeutic strategies. This review describes the disturbed cell cycle control, anti-apoptotic mechanisms, the process of invasion and metastasis and angioneogenesis of pancreatic cancer cells. This knowledge will allow the development of novel therapeutic strategies for the future.

Apoptosis↗