Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 216
Filter
1.
Gefasschirurgie ; 25(6): 408-416, 2020.
Article in German | MEDLINE | ID: mdl-32963422

ABSTRACT

Background: Due to the novelty of COVID­19 there is lack of evidence-based recommendations regarding the mechanical ventilation of these patients. Objective: Identification and delineation of critical parameters enabling individualized lung and diaphragm protective mechanical ventilation. Material and methods: Selective literature search, critical evaluation and discussion of expert recommendations. Results: In the current literature a difference between ARDS in COVID­19 and classical ARDS is described; however, there are no evidence-based recommendations for dealing with this discrepancy. In the past parameters and approaches for a personalized mechanical ventilation strategy were already introduced and applied. Conclusion: Using the parameters presented here it is possible to individualize the mechanical ventilation of COVID­19 patients in order to adjust and increase its compatibility to the heterogeneous clinical presentation of the COVID­19 ARDS.

2.
Cereb Cortex ; 30(6): 3686-3703, 2020 05 18.
Article in English | MEDLINE | ID: mdl-31907512

ABSTRACT

The capacity-limited human brain is constantly confronted with a huge amount of sensory information. Selective attention is needed for biasing neural processing towards relevant information and consequently allows meaningful interaction with the environment. Activity in the alpha-band has been proposed to be related to top-down modulation of neural inhibition and could thus represent a viable candidate to control the priority of stimulus processing. It is, however, unknown whether modulations in the alpha-band directly relate to changes in the sensory gain control of the early visual cortex. Here, we used a spatial cueing paradigm while simultaneously measuring ongoing alpha-band oscillations and steady-state visual evoked potentials (SSVEPs) as a marker of continuous early sensory processing in the human visual cortex. Thereby, the effects of spatial attention for both of these signals and their potential interactions were assessed. As expected, spatial attention modulated both alpha-band and SSVEP responses. However, their modulations were independent of each other and the corresponding activity profiles differed across task demands. Thus, our results challenge the view that modulations of alpha-band activity represent a mechanism that directly alters or controls sensory gain. The potential role of alpha-band oscillations beyond sensory processing will be discussed in light of the present results.


Subject(s)
Alpha Rhythm/physiology , Attention/physiology , Evoked Potentials, Visual/physiology , Spatial Processing/physiology , Visual Cortex/physiology , Adolescent , Adult , Electroencephalography , Female , Humans , Male , Neural Inhibition/physiology , Photic Stimulation , Young Adult
3.
BJOG ; 125(9): 1179-1184, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29328522

ABSTRACT

OBJECTIVE: To evaluate the quality of ultrasound images obtained with cassava flour slurry (CFS) compared with conventional gel in order to determine objectively whether CFS could be a true low-cost alternative. DESIGN: Blinded non-inferiority trial. SETTING: Obstetrical ultrasound unit in an academic medical centre. POPULATION OR SAMPLE: Women with a singleton pregnancy, undergoing anatomy ultrasounds. METHODS: Thirty pregnant women had standard biometry measures obtained with CFS and conventional gel. Images were compared side-by-side in random order by two blinded sonologists and rated for image resolution, detail and total image quality using a 10-cm visual analogue scale. Ratings were compared using paired t-tests. Participant and sonographer experience was measured using five-point Likert scales. MAIN OUTCOME MEASURES: Image resolution, detail, and total image quality. Participant experience of gel regarding irritation, messiness, and ease of removal. RESULTS: We found no significant difference between perceived image quality obtained with CFS (mean = 6.2, SD = 1.2) and commercial gel (mean = 6.4, SD = 1.2) [t (28) = -1.1; P = 0.3]. Images were not rated significantly differently for either reviewer in any measure, any standardized image or any view of a specific anatomic structure. All five sonographers rated CFS as easy to obtain clear images and easy for patient and machine cleanup. Only one participant reported itching with CFS. CONCLUSIONS: CFS produces comparable image quality to commercial ultrasound gel. The dissemination of these results and the simple CFS recipe could significantly increase access to ultrasound for screening, monitoring and diagnostic purposes in resource-limited settings. FUNDING: This study was internally funded by our department. TWEETABLE ABSTRACT: Low-cost homemade cassava flour slurry creates images equal to commercial ultrasound gel, improving access.


Subject(s)
Flour , Image Interpretation, Computer-Assisted/standards , Manihot , Ultrasonography, Prenatal/standards , Adult , Costs and Cost Analysis , Female , Flour/economics , Gels , Humans , Manihot/economics , Pregnancy , Single-Blind Method , Ultrasonography, Prenatal/economics , Ultrasonography, Prenatal/methods
4.
Anaesthesist ; 65(6): 438-48, 2016 Jun.
Article in German | MEDLINE | ID: mdl-27160419

ABSTRACT

BACKGROUND: Patient blood management (PBM) is a multidisciplinary approach focusing on the diagnosis and treatment of preoperative anaemia, the minimisation of blood loss, and the optimisation of the patient-specific anaemia reserve to improve clinical outcomes. Economic aspects of PBM have not yet been sufficiently analysed. OBJECTIVES: The aim of this study is to analyse the costs associated with the clinical principles of PBM and the project costs associated with the implementation of a PBM program from an institutional perspective. MATERIALS AND METHODS: Patient-related costs of materials and services were analysed at the University Hospital Frankfurt for 2013. Personnel costs of all major processes were quantified based on the time required to perform each step. Furthermore, general project costs of the implementation phase were determined. RESULTS: Direct costs of transfusing a single unit of red blood cells can be calculated to a minimum of €147.43. PBM-associated costs varied depending on individual patient requirements. The following costs per patient were calculated: diagnosis of preoperative anaemia €48.69-123.88; treatment of preoperative anaemia (including iron-deficiency anaemia and megaloblastic anaemia) €12.61-127.99; minimising perioperative blood loss (including point-of-care diagnostics, coagulation management and cell salvage) €3.39-1,901.81; and costs associated with the optimisation of the tolerance to anaemia (including patient monitoring and volume therapy) €28.62. General project costs associated with the implementation of PBM were €24,998.24. CONCLUSIONS: PBM combines various alternatives to the transfusion of red blood cells and improves clinical outcome. Costs of PBM vary from institution to institution and depend on the extent to which different aspects of PBM have been implemented. The quantification of costs associated with PBM is essential in order to assess the economic impact of PBM, and thereby, to efficiently re-allocate health care resources. Costs were determined at a single university hospital. Thus, further analyses of both the costs of transfusion and the costs of PBM-principles will be necessary to evaluate the cost-effectiveness of PBM.


Subject(s)
Anemia/economics , Blood Transfusion/economics , Perioperative Care/economics , Anemia/diagnosis , Anemia/therapy , Blood Loss, Surgical/prevention & control , Cost Control , Costs and Cost Analysis , Erythrocyte Transfusion/economics , Hospital Costs , Humans , Personnel, Hospital/economics , Point-of-Care Systems , Preoperative Care/economics , Treatment Outcome
5.
Cell Microbiol ; 18(11): 1570-1582, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27038042

ABSTRACT

The human restricted pathogen Moraxella catarrhalis is an important causal agent for exacerbations in chronic obstructive lung disease in adults. In such patients, increased numbers of granulocytes are present in the airways, which correlate with bacteria-induced exacerbations and severity of the disease. Our study investigated whether the interaction of M. catarrhalis with the human granulocyte-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM)-3 is linked to NF-κB activation, resulting in chemokine production. Granulocytes from healthy donors and NB4 cells were infected with M. catarrhalis in the presence of different inhibitors, blocking antibodies and siRNA. The supernatants were analysed by enzyme-linked immunosorbent assay for chemokines. NF-κB activation was determined using a luciferase reporter gene assay and chromatin-immunoprecipitation. We found evidence that the specific engagement of CEACAM3 by M. catarrhalis ubiquitous surface protein A1 (UspA1) results in the activation of pro-inflammatory events, such as degranulation of neutrophils, ROS production and chemokine secretion. The interaction of UspA1 with CEACAM3 induced the activation of the NF-κB pathway via Syk and the CARD9 pathway and was dependent on the phosphorylation of the CEACAM3 ITAM-like motif. These findings suggest that the CEACAM3 signalling in neutrophils is able to specifically modulate airway inflammation caused by infection with M. catarrhalis.


Subject(s)
CARD Signaling Adaptor Proteins/metabolism , Carcinoembryonic Antigen/metabolism , Granulocytes/physiology , Moraxella catarrhalis/physiology , Moraxellaceae Infections/microbiology , Syk Kinase/metabolism , Cell Degranulation , Chemokines/metabolism , Granulocytes/microbiology , HEK293 Cells , Host-Pathogen Interactions , Humans , Respiratory Burst , Signal Transduction
6.
Article in English | AIM (Africa) | ID: biblio-1258653

ABSTRACT

Introduction The role of Focused Assessment with Sonography for Trauma (FAST) is well described in the literature in high-resource general emergency care settings. However; there are limited data on utilisation of FAST by local providers in limited-resource conflict settings. We describe the first experience of a hospital in E-DRC using the FAST exam in triage to evaluate and expedite blunt and penetrating trauma patients during an armed invasion. Methods HEAL Africa Hospital (HEAL) is a tertiary trauma centre located in Goma; Eastern Democratic Republic of Congo. In 2010; ultrasound training was initiated. During subsequent armed fighting and the invasion of Goma; the hospital adopted the FAST exam as triage tool in the emergency centre (EC). Ultrasound scans were prospectively logged and perceived utility for immediate patient management was recorded. At a 1 year follow-up; a cohort of physician and nurses considered downstream patient recipients were also asked perceived utility towards its use. Results 222/243 (91) of ultrasound scans were recorded by physicians as having positive utility for immediate patient management. 61/243 (25) scans were FAST exams; 24 for obstetric evaluation and 158 were scans for pain management with ultrasound regional anaesthesia. 23/61 (41) of the FAST were reported as positive. Patients with + FAST were immediately prioritised and either a chest tube was placed or taken to the operating room for laparotomy. All 23 patients brought for laparotomy or chest tube were shown to have haemoperitoneum or positive output respectively. Discussion : The introduction of FAST training and requisite equipment in resource stressed healthcare settings is both desirable and feasible. In this study; the introduction of FAST by local providers had an important influence on the decision making process and enabled immediate triage of casualties to laparotomy; chest tube or clinical observations. Prospective controlled research is further needed to evaluate the impact


Subject(s)
Emergency Medical Services , Referral and Consultation , Ultrasonography , Wounds and Injuries
8.
Vox Sang ; 104(1): 19-29, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23252689

ABSTRACT

BACKGROUND: The cobas TaqScreen MPX Test, version 2.0, a multiplex, multi-dye nucleic acid amplification technology (NAT) test from Roche was evaluated by two European Blood Banks, the German Red Cross Blood Donor Service, Frankfurt, Germany and Centro de Hemoterapia y Hemodonación de Castilla y León, Valladolid, Spain. In addition, the cobas TaqScreen DPX Test was evaluated for the simultaneous detection and quantitation of parvovirus B19 and the detection of hepatitis A virus (HAV). STUDY DESIGN AND METHODS: The performances of the two tests were evaluated regarding the analytical sensitivity, the reproducibility of the tests using samples containing low concentrations of each virus and cross-contamination using samples containing high titres of virus. RESULTS: The analytical sensitivity of the MPX Test, version 2.0, obtained by the German Red Cross Blood Donor Service was 1·1, 3·9 and 43·3 IU/ml for HBV, HCV and HIV-1, respectively. The comparable analytical sensitivity at Centro de Hemoterapia y Hemodonación de Castilla y León was 3·5, 17·6 and 50·6 IU/ml for HBV, HCV and HIV-1, respectively. The analytical sensitivity of the DPX test determined by the German Red Cross Blood Donor Service was 0·6 and 3·8 IU/ml for HAV and B19. CONCLUSION: These multiplex and multi-dye blood screening assays represent a flexible NAT screening system for mini-pools between 6 and 96 samples per pool and fulfil all requirements of the European Pharmacopoeia for HCV and B19V testing of plasma for fractionation. The inclusion of a new multi-dye technology means discriminatory assays are no longer required for either test thus improving workflow, turn-around time and minimize the risk of obtaining a reactive result for which the virus cannot be identified.


Subject(s)
Blood Safety , HIV Infections/diagnosis , Hepatitis B/diagnosis , Hepatitis C/diagnosis , Nucleic Acid Amplification Techniques , Blood Banks , Blood Donors , Europe , Genotype , HIV Infections/virology , HIV-1/genetics , HIV-2/genetics , Hepacivirus/genetics , Hepatitis A/diagnosis , Hepatitis A/virology , Hepatitis A virus/genetics , Hepatitis B/virology , Hepatitis B virus/genetics , Hepatitis C/virology , Humans , Mass Screening , Parvovirus B19, Human/genetics , Reproducibility of Results
9.
Article in German | MEDLINE | ID: mdl-21698530

ABSTRACT

Individualized, (stem) cell-based therapies of congenital and acquired illnesses are among the most exciting medical challenges of the twenty-first century. Before the full potential of such therapies can be achieved, many basic scientific and biotechnological questions remain to be answered. What is the ideal source for the generation of such cellular drugs is one of those issues. In many respects, hematopoietic stem cells fulfill the requirements for stem cells as starting material for novel cellular therapeutics, including the simple access to large amounts of stem cells, the availability of good phenotypic markers for their prospective isolation, and an extensive body of knowledge about the in vitro manipulation of these cells. This manuscript discusses the general and specific usability of hematopoietic stem cells as starting material for novel cellular therapeutics and presents some examples of hematological and nonhematological therapeutic approaches which are based on hematopoietic stem cells.


Subject(s)
Biotechnology/methods , Cell Transplantation/methods , Genetic Therapy/methods , Hematopoietic Stem Cell Transplantation/methods , Precision Medicine , Therapies, Investigational/methods , Forecasting , Germany , Humans , Regenerative Medicine/methods
10.
Chirurg ; 82(4): 348-58, 2011 Apr.
Article in German | MEDLINE | ID: mdl-21249326

ABSTRACT

BACKGROUND: The aim of the present study was to assess ex-vivo function of pathogen-inactivated versus conventional platelet concentrates (PC) in the perioperative setting. MATERIAL AND METHODS: A total of 30 patients who underwent cardiac surgery and who postoperatively depended on the transfusion of two platelet concentrates were enrolled into this study. Of the patients 15 received conventional buffy coat PC (conv. PC) and 15 received pathogen-inactivated PC (PI-PC). Age, volume and platelet content of each PC were recorded. Before (T0) and 30 min after PC transfusion (T1), blood samples were taken and platelet function analyses (MEA) and conventional laboratory coagulation analyses were performed. The transfusion-associated increment of platelet concentration (increment) and the corrected count increment (CCI) were assessed at timepoint T1. RESULTS: There were no significant group differences between the groups in MEA analyses or conventional laboratory at T0 or T1. The platelet content per PC was significantly higher in the PI-PC group [3.3 (3.1/3.5)× 10(11) platelets per PI-PC versus 3 (2.9/3)× 10(11) platelets per conv. PC, p<0.001]. Platelet increment (42±27×10(9)/l versus 69.4±29×10(9)/l, p=0.013) was significantly lower in the PI-PC group. CONCLUSION: Whereas ex-vivo analyses of platelet function did not show any group differences at T1, a significantly lower increment was seen in the pilot study after transfusion of PI-PC as compared to conventional PC.


Subject(s)
Blood Preservation/methods , Blood-Borne Pathogens , Heart Diseases/surgery , Platelet Count , Platelet Transfusion/methods , Ultraviolet Rays , Aged , Aged, 80 and over , Blood Buffy Coat , Blood Coagulation Tests , Cohort Studies , Female , Furocoumarins , Germany , Humans , Intensive Care Units , Male , Middle Aged , Platelet Aggregation/drug effects , Platelet Function Tests , Postoperative Care , Prospective Studies
11.
Proc Natl Acad Sci U S A ; 107(31): 13878-82, 2010 Aug 03.
Article in English | MEDLINE | ID: mdl-20643918

ABSTRACT

A central question in the field of attention is whether visual processing is a strictly limited resource, which must be allocated by selective attention. If this were the case, attentional enhancement of one stimulus should invariably lead to suppression of unattended distracter stimuli. Here we examine voluntary cued shifts of feature-selective attention to either one of two superimposed red or blue random dot kinematograms (RDKs) to test whether such a reciprocal relationship between enhancement of an attended and suppression of an unattended stimulus can be observed. The steady-state visual evoked potential (SSVEP), an oscillatory brain response elicited by the flickering RDKs, was measured in human EEG. Supporting limited resources, we observed both an enhancement of the attended and a suppression of the unattended RDK, but this observed reciprocity did not occur concurrently: enhancement of the attended RDK started at 220 ms after cue onset and preceded suppression of the unattended RDK by about 130 ms. Furthermore, we found that behavior was significantly correlated with the SSVEP time course of a measure of selectivity (attended minus unattended) but not with a measure of total activity (attended plus unattended). The significant deviations from a temporally synchronized reciprocity between enhancement and suppression suggest that the enhancement of the attended stimulus may cause the suppression of the unattended stimulus in the present experiment.


Subject(s)
Attention , Behavior/physiology , Brain/physiology , Adolescent , Adult , Brain Mapping , Electroencephalography , Female , Humans , Male , Time Factors , Young Adult
12.
Plant Dis ; 93(3): 322, 2009 Mar.
Article in English | MEDLINE | ID: mdl-30764195

ABSTRACT

Red band needle blight of pines caused by Mycosphaerella pini (anamorph Dothistroma septosporum) has recently been recorded on Scots pine (Pinus sylvestris) at 14 rural districts in southern and central Finland. Scots pine is the most common and commercially most important tree species in Finland. Red bands with aggregations of conidial stromata on otherwise brown attached needles were frequently encountered on saplings and young trees in dense stands and sporadically on lower twigs of mature trees within 2 m of the ground. These symptoms and signs, typical for M. pini (1), were also observed on needles of P. contorta and P. cembra, which occur in Finland in low frequency. Symptoms of red band needle blight and abundant conidial stromata were found in March and April of 2008 after a mild and rainy winter. After this time, the frequency at which fresh acervuli were observed decreased. Conidia were isolated after squeezing conidial stromata into a drop of sterile water and rinsing out the drop onto water agar from where single conidia were picked up from under the microscope with a modified Pasteur pipette. The conidia were hyaline, smooth, thin walled, filiform, 2.0 to 2.7 (2.4) µm wide, and 15 to 37 (29.4) µm long. Germination of the conidia on water agar was 100%. The cultures grew slowly and reached a diameter of 4 to 10 mm within 3 weeks on modified orange serum agar (2) at 20°C and abundantly produced conidia. Complete sequences of the internal transcribed spacer (ITS) region including the 5.8S rRNA gene were obtained for three isolates from different rural districts: Hartola (61°34'N, 26°01'E), Kangasniemi (61°59'N, 26°39'E), and Suonenjoki (62°37'N, 27°07'E). These sequences are deposited in GenBank with Accession Nos. EU834294, EU834295, and EU834296 and are identical to each other and to more than 50 M. pini sequences in GenBank, including those of several Estonian and Austrian isolates. These isolates are deposited in the culture collection of the Finnish Forest Research Institute with identifiers Dot1, Dot2, and Dot8. Symptoms were reproduced after inoculation of 1-year-old Scots pine seedlings growing in seedling trays with 115 cm3 cavities. A conidial suspension (5 to 6·× 103 conidia ml-1) was prepared from two single-conidial cultures (Dot10 and Dot15), combined, and sprayed during July 2008 onto 192 seedlings until needles looked completely wet. Sixty-four seedlings were sprayed with distilled water as a control treatment. Seedlings were incubated outdoors in Suonenjoki and covered with a transparent plastic hood for the first 5 days after inoculation. The first symptoms (brown segments and red bands on needles) appeared on inoculated seedlings 1 month later, and conidial stromata appeared after another 2 to 4 weeks. M. pini was reisolated from the acervuli of 10 sample needles. Three months after inoculation, all inoculated seedlings showed symptoms while all noninoculated seedlings were healthy. It is possible that M. pini has spread recently from the south since it was identified for the first time in Estonia 2 years earlier (3). Although the Gulf of Finland separates Finnish pine forests from Estonian pine forests by approximately 50 to 100 km, spores may have been aerially disseminated over this distance. Alternatively, introduction of M. pini to Finland may have occurred on imported seedlings. References: (1) Anonymous. OEPP/EPPO Bull. 35, 303, 2005. (2) M. Hanso and R. Drenkhan. Plant Pathol. 57:170, 2008. (3) M. M. Müller et al. Mycol. Res. 98:593, 1994.

13.
Brain Res ; 1196: 74-84, 2008 Feb 27.
Article in English | MEDLINE | ID: mdl-18234156

ABSTRACT

Natural stimuli are compiled of numerous features, which are cortically represented in dispersed structures. Synchronized oscillations in the Gamma-Band (>30 Hz; induced Gamma-Band Responses, iGBRs), are regarded as a plausible mechanism to re-integrate these regions into a meaningful cortical object representation. Using electroencephalography (EEG) it was demonstrated that the generators of iGBRs can be localized to temporal, parietal, posterior, and frontal areas. The present magnetoencephalogram (MEG) study intended to replicate these findings in order contribute to the ongoing debate regarding the possible functional difference of high-frequency signals as measured by both techniques. During a standard object recognition task we found an augmentation of the iGBR after the presentation of meaningful as opposed to meaningless stimuli at approximately 160-440 ms after stimulus onset. This peak was localized to inferior temporal gyri, superior parietal lobules and the right middle frontal gyrus. Importantly, most of these brain structures were significantly phase-locked to each other. The implications of these results are twofold: (1) they present further evidence for the view that iGBRs signify neuronal activity in a broadly distributed network during object recognition. (2) MEG is well suited to detect induced high-frequency oscillations with a very similar morphology as revealed by EEG recordings, thereby eliminating known problems with electroencephalographical methods (e.g. reference confounds). In contrast to the iGBR, the localization of event-related fields (ERFs) and evoked Gamma-Band Response (eGBRs) revealed generators in focal visual areas, and thus, seem to mirror early sensory processing.


Subject(s)
Brain Mapping , Cerebral Cortex/physiology , Electroencephalography , Magnetoencephalography , Pattern Recognition, Visual/physiology , Adult , Analysis of Variance , Cerebral Cortex/anatomy & histology , Family , Female , Humans , Male , Photic Stimulation/methods
14.
Neuroimage ; 35(1): 255-62, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17187993

ABSTRACT

Focusing attention to a specific body location has been shown to improve processing of events presented at this body location. One important debate concerns the stage in the somatosensory pathway at which the neural response is modulated when one attends to a tactile stimulus. Previous studies focused on components of the somatosensory evoked potential to transient stimuli, and demonstrated an early cortical attentional modulation. The neural basis of sustained spatial stimulus processing with continuous stimulation remains, however, largely unexplored. A way to approach this topic is to present vibrating stimuli with different frequencies for several seconds simultaneously to different body locations while subjects have to attend to the one or the other location. The amplitude of the somatosensory steady-state evoked potential (SSSEP) elicited by these vibrating stimuli increases with attention. On the basis of 128 electrode recordings, we investigated the topographical distribution and the underlying cortical sources by means of a VARETA approach of this attentional amplitude modulation of the SSSEP. Sustained spatial attention was found to be mediated in primary somatosensory cortex with no differences in SSSEP amplitude topographies between attended and unattended body locations. These result patterns were seen as evidence for a low-level sensory gain control mechanism in tactile spatial attention.


Subject(s)
Attention/physiology , Somatosensory Cortex/physiology , Space Perception/physiology , Adult , Data Interpretation, Statistical , Electroencephalography , Evoked Potentials, Somatosensory/physiology , Female , Fingers/physiology , Functional Laterality/physiology , Humans , Male , Touch/physiology , Vibration
15.
Proc Natl Acad Sci U S A ; 103(38): 14250-4, 2006 Sep 19.
Article in English | MEDLINE | ID: mdl-16956975

ABSTRACT

We used an electrophysiological measure of selective stimulus processing (the steady-state visual evoked potential, SSVEP) to investigate feature-specific attention to color cues. Subjects viewed a display consisting of spatially intermingled red and blue dots that continually shifted their positions at random. The red and blue dots flickered at different frequencies and thereby elicited distinguishable SSVEP signals in the visual cortex. Paying attention selectively to either the red or blue dot population produced an enhanced amplitude of its frequency-tagged SSVEP, which was localized by source modeling to early levels of the visual cortex. A control experiment showed that this selection was based on color rather than flicker frequency cues. This signal amplification of attended color items provides an empirical basis for the rapid identification of feature conjunctions during visual search, as proposed by "guided search" models.


Subject(s)
Attention/physiology , Color Perception/physiology , Color , Form Perception/physiology , Adult , Behavior/physiology , Brain Mapping , Evoked Potentials, Visual/physiology , Female , Humans , Photic Stimulation , Random Allocation
16.
Int J Sports Med ; 26(8): 645-50, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16158369

ABSTRACT

The present study was designed to investigate whether the stress of a half-marathon race can induce myocardial cell injury or left ventricular dysfunction in moderately trained runners of both gender, as assessed by post-race plasma concentrations of biochemical cardiac-specific markers and by quantitative echocardiographic measurements. We examined 12 male (mean+/-SD); age: 42.8+/-7.3 yr; height: 177.6+/-7.4 cm; body mass: 75.6+/-9.4 kg; BMI: 24.1+/-1.8 and 13 female (mean+/-SD); age: 39.0+/-6.5 yr; height: 164.6+/-6.2 cm; body mass: 58.4+/-9.8 kg; BMI: 21.5+/-3.4 recreational runners, who completed a half-marathon race. Blood samples were collected from each subject before the half-marathon race as well as 20 min and 2 h post-race and cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured. Quantitative echocardiographic analyses of wall dimensions and ejection fraction were also obtained from 14 of 25 subjects within 1 wk after the race. Both blood markers showed significant changes (p<0.05-0.001) over the time course of the three blood draws. A significant percentage of laboratory analytes analyzed in this study were outside the reference ranges and fulfilled conventional criteria for cardiac muscle damage. However, echocardiography within one week following the competition did not show any evidence that running a half-marathon competition damages the myocardium. Strenuous endurance exercise in middle-aged recreational runners induces a significant elevation of biochemical cardiac-specific markers, which may reflect transient subclinical myocardial damage, but can also reflect a physiological reparative or adaptive process.


Subject(s)
Exercise/physiology , Natriuretic Peptide, Brain/blood , Peptide Fragments/blood , Physical Endurance/physiology , Troponin I/blood , Adult , Female , Humans , Male , Myocardium/pathology
17.
Cell Death Differ ; 11(7): 760-70, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15017383

ABSTRACT

Potassium withdrawal is commonly used to induce caspase-mediated apoptosis in cerebellar granule neurons in vitro. However, the underlying and cell death-initiating mechanisms are unknown. We firstly investigated potassium efflux through the outward delayed rectifier K+ current (Ik) as a potential mediator. However, tetraethylammoniumchloride, an inhibitor of Ik, was ineffective to block apoptosis after potassium withdrawal. Since potassium withdrawal reduced intracellular pH (pHi) from 7.4 to 7.2, we secondly investigated the effects of intracellular acidosis. To study intracellular acidosis in cerebellar granule neurons, we inhibited the Na+/H+ exchanger (NHE) with 4-isopropyl-3-methylsulfonylbenzoyl-guanidine methanesulfonate (HOE 642) and 5-(N-ethyl-N-isopropyl)-amiloride. Both inhibitors concentration-dependently induced cell death and potentiated cell death after potassium withdrawal. Although inhibition of the NHE induced cell death with morphological criteria of apoptosis in light and electron microscopy including chromatin condensation, positive TUNEL staining and cell shrinkage, no internucleosomal DNA cleavage or activation of caspases was detected. In contrast to potassium withdrawal-induced apoptosis, cell death induced by intracellular acidification was not prevented by insulin-like growth factor-1, cyclo-adenosine-monophosphate, caspase inhibitors and transfection with an adenovirus expressing Bcl-XL. However, cycloheximide protected cerebellar granule neurons from death induced by potassium withdrawal as well as from death after treatment with HOE 642. Therefore, the molecular mechanisms leading to cell death after acidification appear to be different from the mechanisms after potassium withdrawal and resemble the biochemical but not the morphological characteristics of paraptosis.


Subject(s)
Acidosis/etiology , Amiloride/analogs & derivatives , Apoptosis/drug effects , Caspases/physiology , Cerebellum/cytology , Neurons/physiology , Sodium-Hydrogen Exchangers/antagonists & inhibitors , Acidosis/metabolism , Adenoviridae/genetics , Amiloride/pharmacology , Animals , Cell Survival , Cells, Cultured , Cycloheximide/pharmacology , Dose-Response Relationship, Drug , Guanidines/pharmacology , Hydrogen-Ion Concentration/drug effects , Neurons/drug effects , Neurons/ultrastructure , Potassium/metabolism , Protein Synthesis Inhibitors/pharmacology , Rats , Rats, Sprague-Dawley , Sodium-Hydrogen Exchangers/drug effects , Sulfones/pharmacology
18.
Nature ; 424(6946): 309-12, 2003 Jul 17.
Article in English | MEDLINE | ID: mdl-12867981

ABSTRACT

By voluntarily directing attention to a specific region of a visual scene, we can improve our perception of stimuli at that location. This ability to focus attention upon specific zones of the visual field has been described metaphorically as a moveable spotlight or zoom lens that facilitates the processing of stimuli within its 'beam'. A long-standing controversy has centred on the question of whether the spotlight of spatial attention has a unitary beam or whether it can be divided flexibly to disparate locations. Evidence supporting the unitary spotlight view has come from numerous behavioural and electrophysiological studies. Recent experiments, however, indicate that the spotlight of spatial attention may be divided between non-contiguous zones of the visual field for very brief stimulus exposures (&<100 ms). Here we use an electrophysiological measure of attentional allocation (the steady-state visual evoked potential) to show that the spotlight may be divided between spatially separated locations (excluding interposed locations) over more extended time periods. This spotlight division appears to be accomplished at an early stage of visual-cortical processing.


Subject(s)
Attention/physiology , Visual Fields/physiology , Visual Perception/physiology , Electrophysiology , Eye Movements/physiology , Fixation, Ocular/physiology , Humans , Photic Stimulation
19.
Acta Med Austriaca ; 30(2): 55-8, 2003.
Article in German | MEDLINE | ID: mdl-12752090

ABSTRACT

In 19 marathon runners of both sexes, plasma concentrations of total creatine kinase (CK) activity, CKMB mass, myoglobin and troponin I were determined before and immediately after the race. Total CK activity and myoglobin increased significantly in all runners and showed neither a correlation with the individual age of the runners nor with the time they needed to reach the goal. In 12 of the runners, CKMB mass increased during the race to a level suggesting myocardial necrosis. However, the runners did not show any detectable deterioration of cardiac function after the race. The appearance of considerable amounts of muscle proteins in plasma precipitated by the muscle strain during the race seems explained by damage of skeletal muscle detected by histological studies. These phenomena may also be a consequence of profoundly disturbed cellular permeability, perhaps due to a kind of local stunning of muscle tissue by prolonged muscular strain.


Subject(s)
Muscle Proteins/blood , Running/physiology , Sports/physiology , Adult , Creatine Kinase/blood , Female , Humans , Male , Myoglobin/blood , Troponin I/blood
20.
Article in English | MEDLINE | ID: mdl-12650760

ABSTRACT

The paper describes the development of a method for the determination of 15 nucleotides in cultured mononuclear blood and umbilical vein endothelial cell lysates by solvent generated ion-pair chromatography. The phase system is generated via a mobile phase of 100 mM phosphoric acid adjusted to pH 6.2 with triethylamine. Nucleotides are eluted by applying a linear magnesium ion gradient. The method is robust, highly reproducible and easily adaptable to other cell lysates and allows the separation and quantitation of the nucleotides with detection limits in the range from 17 (ADP) to 126 (CDP) pmol in 20-microl aliquots.


Subject(s)
Chromatography, High Pressure Liquid/methods , Nucleotides/blood , Umbilical Veins/metabolism , Humans , Hydrogen-Ion Concentration , Solvents , Umbilical Veins/cytology
SELECTION OF CITATIONS
SEARCH DETAIL
...