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Biomedical subjects

W Sturm

Publications and source records attributed to W Sturm.

At least 19 recordsLinked to original sources
PubMed2006

Alertness-training in neglect: behavioral and imaging results.

PURPOSE: It has been proposed that the right hemisphere alerting network co-activates, either directly or via the brainstem, the spatial attention system in the parietal cortex. The observation that measures of impaired alertness and sustained attention can be used to predict the outcome of neglect might suggest such a relationship, too. The aim of the present study was to investigate the effects of alertness training on hemispatial neglect. METHOD: A three-week computerised alertness training was applied to patients with chronic (> 3 months) stable visuospatial hemineglect. Training effects were investigated both in a single case and in a group of 7 patients by means of neuropsychological tests and functional magnetic resonance imaging (fMRI). RESULTS: After the training, the patients showed a significant improvement in a neglect test battery above any natural fluctuation during a three-week baseline phase. Improvements in the neglect tasks were accompanied by an increase of both right and left hemisphere frontal, anterior cingulate and superior parietal activation, areas known to be associated with both alertness and spatial attention. Four weeks after the end of the training, the patients' neglect test performance had mostly returned to baseline. Despite decreases of activation in some of the initially reactivated areas, increases in neural activity bilaterally in frontal areas, in the right anterior cingulate cortex, the right angular gyrus and in the left temporoparietal cortex remained. An Optokinetic Stimulation Training (OKS) in a control group of another 7 neglect patients led to comparable behavioral results. After the training, however, there was a reactivation mainly in posterior parts of both hemispheres suggesting training specific functional reorganization. CONCLUSION: The limited stability of the behavioral and reactivation results over time demonstrates that a three-week alertness or OKS training alone does not result in long lasting behavioral improvements and stable reactivation patterns in every patient. We rather suggest that combining alertness and spatial attention oriented training procedures might lead to a more stable amelioration of neglect symptoms.

Adult↗
PubMed2005

Spatial attention: more than intrinsic alerting?

It has been proposed that the right hemisphere alerting network co-activates, either directly or via the brainstem, the attention system in the parietal cortex involved in spatial attention. The observation that impaired alertness and sustained attention can predict the outcome of neglect might suggest such a relationship, too. In the present fMRI study, we intended to analyse and compare the functional anatomy of two attentional conditions both involving intrinsic (endogenous) alerting and fixation but differing with respect to the degree of spatially distributed attention by using the same paradigm under two different attentional conditions. In a group of ten participants, both a focused and a distributed visuospatial attention condition evoked similar patterns of activation in dorsolateral prefrontal regions, in the anterior cingulate gyrus, in the superior and inferior parietal cortex as well as in the superior temporal gyrus and in the thalamus. These activation foci were stronger in the right hemisphere under both conditions. After subtraction of the alertness condition with focused spatial attention, distributed spatial attention with stimuli appearing at unpredictable locations within both visual fields induced additional bilateral activations only in the left and right superior parietal cortex and in the right precuneus suggesting that these regions are specific for a more widespread dispersion of spatial attention.

Adult↗
PubMed2005

Impact of alertness training on spatial neglect: a behavioural and fMRI study.

The effects of a 3-week computerised alertness training on chronic (>3 months) visuospatial hemineglect were investigated prospectively in seven patients by means of neuropsychological tests and functional magnetic resonance imaging (fMRI). Following the alertness training, the group showed improved alertness and a significant improvement in the performance of a neglect test battery over and above any improvement during a 3-week baseline phase. Improvements in the neglect tasks were accompanied by an increase of right hemisphere neural activity in frontal cortex, anterior cingulate cortex, precuneus, cuneus and angular gyrus. These areas have previously been associated with alertness and spatial attention. A similar pattern of increased neural activity was found for the left hemisphere. Four weeks after the end of the training, the patients' neglect test performance had mostly returned to baseline, while the increases in neural activity bilaterally in frontal areas, in the right anterior cingulate cortex, the right angular gyrus and the left temporoparietal cortex remained. The data show that a 3-week computerised alertness training can improve performance both in alertness and neglect tests and that these behavioural improvements are associated with reactivation in areas associated with alerting and visuospatial attention. The limited stability of these effects over time suggests that a 3-week alertness training alone does not result in long lasting improvements in every patient, but refining the treatment protocol may lead to a more stable amelioration of neglect symptoms.

Adult↗
PubMed2005

Laparoscopic retroperitoneal lymphadenectomy in the management of low-stage testicular cancer: technique and results.

Retroperitoneal lymph node dissection (RPLND) is still the most sensitive and specific method for detection of lymph node metastases of testicular cancer. Because of its invasiveness and morbidity the acceptance of open RPLND has decreased significantly resulting in a diagnostic deficit. To reduce morbidity and to increase the acceptance of RPLND, laparoscopy has been introduced. Meanwhile, clinical data with long-term follow-ups are available demonstrating the technical feasibility and oncological safety of laparoscopic RPLND. Studies comparing laparoscopy and open surgery could show advantages for the laparoscopic approach concerning blood loss, intraoperative complications and operative time. Antegrade ejaculation can be preserved in the majority of patients. In conclusion, laparoscopic RPLND is a safe method for the management of low-stage germ cell tumors with minimal invasiveness and excellent clinical results. With an increasing number of urologists trained in laparoscopy and an increasing number of published data, it may become a standard approach for low-stage nonseminomatous testicular cancer.

Journal Article↗
PubMed2004

Sensitive detection of tumour cells in effusions by combining cytology and fluorescence in situ hybridisation (FISH).

Diagnosis of malignant cells in effusions is important for staging procedures and resulting therapeutic decisions. Cytodiagnostics in effusions is sometimes difficult since reactive mesothelial cells can mimic malignant cells. We used fluorescence in situ hybridisation (FISH) in single-colour or if appropriate in dual-colour evaluation to detect chromosomal aberrations in effusion cells as markers of malignancy, to raise the diagnostic yield. Cytologic and FISH evaluations--by using probes representing several chromosomes always including chromosomes 11 and 17--were performed in 358 effusion fluids. Cytology was positive for malignancy in 44.4% of all effusions, whereas FISH was positive in 53.9% (P=0.0001). The combination of cytology and FISH was diagnostic for malignancy in 60.9% of effusions. Diagnostic superiority of FISH was demonstrated in effusions from breast cancer, lung cancer, pancreatic cancer, and in effusions from the entire group of gynaecological and gastrointestinal carcinomas. In transudates (effusion protein <2.5 g dl(-1)), malignant cells were detectable by cytology, FISH, and combined use of both methods in 18.6, 30, and 37.1% of effusions, respectively, suggesting that cytologic and molecular analysis should be performed also with transudates. In conclusion, FISH in combination with conventional cytology is a highly sensitive and specific diagnostic tool for detecting malignant cells in effusions.

Aneuploidy↗
PubMed2004

Large-vessel arteritis and myelodysplastic syndrome: report of two cases.

Myelodysplastic syndrome (MDS) is frequently associated with autoimmune diseases such as polymyalgia, arthritis, and rarely, with systemic vasculitis. The pathogenesis of these autoimmune complications remains unknown, but there is increasing evidence of profound immune dysregulation in MDS. In the few cases reported so far, vasculitides associated with MDS affected mainly cutaneous vessels. Here we describe two cases of acute large-vessel vasculitis in association with MDS. The first patient is a 67-yr-old male presenting with a massive large-vessel arteritis as primary manifestation of refractory anemia with excess of blasts type 1 (RAEB-1). The second patient is a 60-yr-old male, who presented with acute thoracic aortitis after a 2-yr history of refractory anemia with ringed sideroblasts (RARS). Both patients received immunosuppressive treatment with steroids, leading to rapid improvement of systemic inflammatory symptoms, vessel wall injury and peripheral blood counts. Whereas the first patient displayed sustained favorable hematologic responses under long-term steroid therapy, there was a rapid transformation into secondary acute myeloid leukemia in the second patient. We conclude that large-vessel vasculitis should be added to the list of potential autoimmune complications in MDS. In this clinical setting, steroid therapy may alleviate inflammatory symptoms and result in beneficial hematologic responses.

Aged↗
PubMed2003

Heart rate response to ultraendurance cycling.

The heart rate (HR) response to ultraendurance cycling is poorly understood. This case report describes the exercise intensity of ultraendurance cycling by means of HR monitoring in a well trained male amateur cyclist performing the Otztal Radmarathon twice en bloque in a circuit of two identical laps (distance 460 km; cumulative altitude difference 11,000 m). The overall intensity was moderate (HR(mean) = 130 beats/min; HR(mean)/HR(max) = 0.71) corresponding to an average individual workload of 47% of VO(2)MAX. Almost the whole race was performed under aerobic conditions (99.6%); high intensity work was negligible (0.4%). The average speed and the HR response also declined in the course of the two laps, average speed by 17.2% (23.8 to 19.7 km/h), HR(mean) by 10.1% (138 to 124 beats/min), and HR(mean)/HR(max) by 10.7% (0.75 to 0.67). This scale of HR decrease corresponds to comparable data gained in the field of triathlon and represents a specific cardiac feature of ultraendurance exercise in general.

Adult↗
PubMed2002

Exercise intensity of cycle-touring events.

The aim of the study was to analyze the exercise intensity of recreational cyclists participating in a cycling-touring event. In 14 male healthy recreational cyclists heart rate (HR) monitoring was performed during the Otztal Radmarathon 1999 (distance: 230 km; altitude difference: 5500 m) in order to evaluate the HR response and to estimate the cardiopulmonary strains for the less-trained athlete confronted with such a marathon. Four different exercise intensities were defined as percentages of maximal HR (HR(max)) as follows: recovery HR (HR(re)) < 70 % of HR max; moderate aerobic HR (HR(ma)) = 70 - 80 %; intense aerobic HR (HR(ia)) = 80 - 90 %; and anaerobic HR (HR(an)) > 90 %. All athletes finished the competition successfully. The mean racing time was 10 h 14 min, the average speed 22.5 km/h. The mean HR(max) was 188 bpm, the average value of the measured HRs (HR(average)) was 145 bpm resulting in a mean HR(average)/HR(max) ratio of 0.77. Athletes spent 18.5 % (1 h 54 min) of total race time within HR(re), 28 % (2 h 52 min) within HR(ma), 39.5 % (4 h 02 min) within HR(ia), and 14 % (1 h 26 min) within HR(an). The vast majority of exercise was done under "aerobic conditions" (HR(re) + HR(ma) + HR(ia) = 86 % or 8 h 48 min) - confirming the knowledge that the aerobic energy supply is crucial for the performance of long-term exercise. The large amount of high exercise intensities (HR(ia) + HR(an) = 53.5 % or 5 h 30 min), however, features the intense cardiopulmonary strains evoked by such competitions. The HR response was related to the course profile with HRs significantly declining in all subjects to an extent of 10 % during the course of race. Our findings show that the exercise intensity borne by recreational cyclists during a cycle-touring event is high and very similar to that of professionals. With respect to the high cardiovascular strains a thorough medical screening is advisable for any participant of such an event combining both high volume and high intensity loads.

Adult↗
PubMed2001

Flow-mediated vasodilation of the femoral and brachial artery induced by exercise in healthy nonsmoking and smoking men.

OBJECTIVES: We sought to analyze diameter changes of conduit arteries in response to whole-body exercise and hypothesized that this response might be endothelium-dependent and, therefore, impaired in smokers. BACKGROUND: Hyperemia and coincident vasodilation are pivotal mechanisms for meeting the increased metabolic demands of active muscle tissue during physical exercise, but studies in humans are sparse. METHODS: We studied diameter and blood flow of the femoral and brachial arteries in response to a submaximal bicycle exercise test in 10 nonsmoking and 8 smoking healthy male subjects. During an exercise period of 40 min the investigated conduit arteries were periodically scanned in longitudinal sections by high-resolution ultrasound. In the same subjects flow-mediated dilation (FMD) of the brachial artery was recorded by inducing an ischemia through a forearm-occluding cuff. RESULTS: In response to exercise the diameter of the femoral artery significantly increased in both nonsmokers and smokers, with a diminished response in smokers (9.2 +/- 1.9% vs. 4.8 +/- 1.6%, p < 0.001). Flow-mediated dilation of the brachial artery induced by forearm occlusion was also reduced in smoking subjects, revealing a strong correlation between these different methods of FMD (exercise vs. forearm ischemia) (r = 0.88, p < 0.001). In contrast, blood flow increase of the femoral artery was similar in nonsmoking and smoking subjects (392 +/- 77% vs. 382 +/- 109%, p = NS). CONCLUSIONS: Conduit arteries react with a flow-mediated dilation in response to whole-body exercise. The impairment of this vasodilation observed in smokers was strongly related to a decrease of endothelium-dependent dilation induced by forearm ischemia, indicating that endothelial dysfunction represents the underlying mechanism.

Adult↗
PubMed2001

Effects of blood estrogen level on cortical activation patterns during cognitive activation as measured by functional MRI.

Modulation of the blood estrogen level as it occurs during the menstrual cycle has a strong influence on both neuropsychological and neurophysiological parameters. One of currently preferred hypotheses is that the menstrual cycle hormones modulate functional hemispheric lateralization. We examined six male and six female subjects by functional magnetic resonance imaging (fMRI) to image cortical activation patterns associated with cognitive and motor activation to determine whether these changes during the menstrual cycle can be visualized. Female subjects, who did not use oral contraceptives, were scanned twice, once during the menses and once on the 11/12 day of the menstrual cycle. A word-stem-completion task, a mental rotation task and a simple motor task were performed by all subjects. Our data provide evidence that the menstrual cycle hormones influence the overall level of cerebral hemodynamics to a much stronger degree than they influence the activation pattern itself. No differences were seen between male subjects and female subjects during the low estrogen phase. During both neuropsychological tasks blood estrogen level had a profound effect on the size but not on the lateralization or the localization of cortical activation patterns. The female brain under estrogen showed a marked increase in perfusion in cortical areas involved in both cognitive tasks, whereas the hemodynamic effects during the motor tasks were less pronounced. This might be due to differences in neuronal or endothelian receptor concentration, differences in synaptic function, or, most likely, changes in the cerebrovascular anatomy in different cortical regions.

Adult↗
PubMed2001

On the functional neuroanatomy of intrinsic and phasic alertness.

Intrinsic and phasic alertness are the most basic aspects of attention intensity probably constituting the basis for the more complex and capacity-demanding aspects of attention selectivity. Intrinsic alertness represents the cognitive control of wakefulness and arousal and is typically assessed by simple reaction time tasks without a preceding warning stimulus. Phasic alertness, in contrast, is called for in reaction time tasks in which a warning stimulus precedes the target, and it represents the ability to increase response readiness subsequent to external cueing. We report PET and fMRI data from both the literature and our own experiments to delineate the cortical and subcortical networks subserving alertness, sustained attention (as another aspect of attention intensity), and spatial orienting of attention. Irrespective of stimulus modality, there seems to exist a mostly right-hemispheric frontal, parietal, thalamic, and brain-stem network which is coactivated by alerting and orienting attentional demands. These findings corroborate both the hypothesis of a frontal modulation of brain-stem activation probably via the reticular nucleus of the thalamus and of a coactivation of the posterior attention system involved in spatial orienting by the anterior alerting network. Under conditions of phasic alertness there are additional activations of left-hemisphere frontal and parietal structures which are interpreted as basal aspects of attention selectivity rather than additional features of alerting.

Arousal↗
PubMed2001

Pronounced postprandial lipemia impairs endothelium-dependent dilation of the brachial artery in men.

OBJECTIVE: Pronounced postprandial lipemia has been established as a risk factor for cardiovascular disease, but reports regarding its effect on endothelial function have been controversial. In the present study the influence of a standardized fatty meal with its ensuing postprandial lipemia of highly varying magnitude on endothelium-dependent dilation (EDD) was investigated. METHODS: In 17 healthy, normolipidemic men EDD of the brachial artery was quantified in two series of three measurements each. In both series initial measurements were performed at 08:00 h after an overnight fast followed by measurements at 12:00 and 16:00 h, in the first series with continued fasting and in the second following the ingestion of a standardized fatty test meal 4 and 8 h postprandially. RESULTS: Measurements of EDD in the fasting state revealed the recently appreciated diurnal variation with higher values in noon and afternoon hours compared with morning values (2.5+/-1.6% at 08:00, 7.5+/-2.7% at 12:00, and 7.0+/-2.1% at 16:00 h, P<0.001 by analysis of variance). Postprandial EDD values measured at 12:00 h were, at the average, lower than fasting EDD values measured at 12:00 h and correlated inversely with the magnitude of postprandial triglyceridemia (r=-0.81, P<0.001). In multivariate analysis, higher postprandial lipemia was associated with impaired postprandial EDD (P<0.001) independent of fasting triglycerides, low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol, insulin, age and body mass index. CONCLUSION: We conclude that pronounced postprandial lipemia is associated with transient impairment of endothelial function. Our findings support the notion that impaired triglyceride metabolic capacity plays an important role in atherogenesis.

Adult↗
PubMed2001

Flow-mediated, endothelium-dependent vasodilatation is impaired in male body builders taking anabolic-androgenic steroids.

Self-administration of anabolic-androgenic steroids to increase muscular strength and lean body mass has been used widely among athletes. Flow mediated dilatation (FMD) determined by ultrasound of the brachial artery is accepted as both an in vivo index of endothelial function and an indicator for future atherosclerosis. FMD was calculated in 20 male non-smoking body builders in different phases of their training cycle and in six male non-smoking control athletes. Ultrasound studies of the brachial artery were performed according to the protocol of Celermajer et al. Of the entire training cycle, work-out phase was training phase without actual intake of anabolic-androgenic steroids over 8 weeks; build-up phase included actual intake of anabolic-androgenic steroids; and competition phase consisted of 8 weeks post intake of anabolic-androgenic steroids. Baseline characteristics did not differ between body builder groups except for a higher weight in competition phase body builders. Hormonal analysis revealed suppressed luteinizing hormone and follicle stimulating hormone levels in build-up phase body builders. The lipid profiles showed a marked reduction of HDL-C in build-up phase body builders. FMD was reduced in body builders of all phases when compared to control athletes (work-out phase: 2.5+/-2.7%; build-up phase: 2.1+/-3.0%; competition phase: 0.4+/-2.9% vs. 10.9+/-4.4%, P<0.05 by pairwise comparison using Scheffe's test for work-out phase, build-up phase and competition phase vs. control athletes). The glyceryl trinitrate-induced vasodilatation was diminished, though not statistically significantly, in body builders when compared with control athletes. The differences in FMD persisted after adjustment for vessel size. Our data indicate that intake of anabolic-androgenic steroids is associated with both an atherogenic blood lipid profile and endothelial dysfunction and thus may pose an increased risk of atherosclerosis.

Adult↗
PubMed2001

Neutrophil degranulation induced by Haemophilus ducreyi.

Haemophilus ducreyi is the causative bacterium of genital ulcers, which are collectively known as chancroid. Little is known about the cytotoxicity of H. ducreyi. The virulent strains are relatively resistant to phagocytosis and apoptosis by neutrophils. Therefore, experiments were designed to examine whether neutrophil degranulation caused by H. ducrey would provide insights into the virulence mechanisms through which cellular damage is affected by the organism. Clinical isolates of eight strains of H. ducreyi and the culture strain type CIP542 (Collection Institute Pasteur) were incubated with neutrophils harvested from human donor blood. The release by the organism of lysosomal enzymes from intracellular granules of neutrophils was indicative of degranulation. The results showed that H. ducreyi triggered the release of lysosomal enzymes from human neutrophils, and that the magnitude of the release was dependent both on the ratio of bacteria to neutrophils and the duration of incubation. In vitro experiments involving HeLa cells were designed to determine the manner in which H. ducreyi initiated the process of degranulation. The morphological changes associated with degranulation were visualized by confocal and transmission electron microscopy. This is the first report that describes degranulation of neutrophils induced by H. ducreyi which causes chancroid infection.

Cathepsin D↗
PubMed2000

Imported malaria: six cases of severe Plasmodium falciparum infection in Innsbruck, Austria, within a period of five weeks (February/March 1999)

Six patients (age, 30-76; 3 male, 3 female) with severe malaria tropica were admitted to the Department of Internal Medicine of the Innsbruck University Hospital within a time period of five weeks. All patients had recently visited classical malaria regions some days before admission: five patients the sub-Saharan Africa and one patient Thailand and Vietnam. All six patients had to be treated in the Intensive Care Unit. Three patients developed an acute respiratory distress syndrome. Two patients died of multi-organ failure. All six patients were treated with quinine and doxycycline intravenously. In one case, exchange transfusion was performed. Only two of six patients had taken prophylactic medication: one patient chloroquine and proguanil and the other mefloquine (she suffered from a severe gastroenteritis during the journey).

Acute Disease↗
PubMed2000

Thalamic and cortical high-frequency (600 Hz) somatosensory-evoked potential (SEP) components are modulated by slight arousal changes in awake subjects.

Human somatosensory-evoked potentials (SEP) recorded at the scalp after conventional electrical median-nerve stimulation contain a low-amplitude (<500 nV), high-frequency (approximately 600 Hz) burst of repetitive wavelets, which are superimposed onto the primary cortical response N20. Previous electroencephalographic (EEG) studies have shown: (1) that these wavelets are generated near the hand area of the primary somatosensory cortex and in deep fibers of thalamocortical afferences; and (2) that only the 600-Hz burst, but not the N20 is decreased during sleep. Since the thalamus is involved in regulating both, selective attention and arousal, the present study aimed at characterizing the effects of focused attention and slight arousal changes on the 600-Hz oscillations. A dipole-source analysis of 64-channel SEP recordings after electric right-median-nerve stimulation allowed the comparison of brainstem, thalamic, and two cortical (one tangential, one radial) source activities in ten awake human subjects under two slightly different arousal states (eyes open vs. eyes closed), each tested for three conditions of focused attention (directed towards rare acoustic and right- or left-hand somatosensory target stimuli). While the N20 was not modified at all, the source strength of the high-frequency wavelet burst was significantly increased for eyes opened versus eyes closed, at the thalamic source site as well as for the tangentially oriented cortical source. In contrast, there were no significant differences between conditions with different attentional targets. This evidence for modulatory effects of increased arousal (eyes open) on both thalamic and cortically generated high-frequency SEP activity fits the hypothesis that the 600-Hz SEP burst at least partially represents an arousal-dependent signal generated at the thalamic level and transmitted to the primary somatosensory cortex.

Adult↗