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Showing papers by "University of Jena published in 1997"


Journal ArticleDOI
TL;DR: The error-related negativity is the manifestation of the activity of a generic neural system involved in error detection, and the distribution of the scalp potential was consistent with a local source in the anterior cingulate cortex or a more distributed sources in the supplementary motor areas.
Abstract: We examined scalp-recorded event-related potentials following feedback stimuli in a time-estimation task. Six hundred msec after indicating the end of a 1 sec interval, subjects received a visual, auditory, or somatosensory stimulus that indicated whether the interval they had produced was correct. Following feedback indicating incorrect performance, a negative deflection occurred, whose characteristics corresponded closely to those of the component (the error-related negativity) that accompanies errors in choice reaction time tasks. Furthermore, equivalent dipole analysis suggested that, for all three modalities, the distribution of the scalp potential was consistent with a local source in the anterior cingulate cortex or a more distributed source in the supplementary motor areas. These loci correspond closely to those described previously for the error-related negativity. We conclude that the error-related negativity is the manifestation of the activity of a “generic” neural system involved in error detection.

1,423 citations


Journal ArticleDOI
02 Jan 1997-Nature
TL;DR: It is shown that Th1 cells, but not Th2 cells, are able to bind to P- selectin and E-selectin, indicating that selective recruitment is an additional level of regulation for both effector function profile and character of a local immune response.
Abstract: When activated, T helper cells differentiate into one of two subsets, Th1 and Th2, characterized by distinct profiles of cytokine production. Th1 cells activate pro-inflammatory effector mechanisms involved in protection and autoimmunity, whereas Th2 cells induce humoral and allergic responses and downregulate local inflammation. Apart from differences in the repertoire of cytokines, no phenotypic attributes are established that distinguish the two subsets. Here we show that Th1 cells, but not Th2 cells, are able to bind to P-selectin and E-selectin. Moreover, only Th1 cells can efficiently enter inflamed sites in Th1-dominated models, such as sensitized skin or arthritic joints, but not in a Th2-dominated allergic response. Immigration of Th1 cells into inflamed skin can be blocked by antibodies against P- and E-selectin. These results provide evidence for adhesion mechanisms to distinguish between the two T helper subsets and mediate their differential trafficking. They indicate that selective recruitment is an additional level of regulation for both effector function profile and character of a local immune response.

729 citations


Journal ArticleDOI
17 Jan 1997-Science
TL;DR: Findings indicate that phosphoinositide 3-kinase γ mediates Gβγ-dependent regulation of the MAPK signaling pathway.
Abstract: The tyrosine kinase class of receptors induces mitogen-activated protein kinase (MAPK) activation through the sequential interaction of the signaling proteins Grb2, Sos, Ras, Raf, and MEK. Receptors coupled to heterotrimeric guanine triphosphate-binding protein (G protein) stimulate MAPK through Gbetagamma subunits, but the subsequent intervening molecules are still poorly defined. Overexpression of phosphoinositide 3-kinase gamma (PI3Kgamma) in COS-7 cells activated MAPK in a Gbetagamma-dependent fashion, and expression of a catalytically inactive mutant of PI3Kgamma abolished the stimulation of MAPK by Gbetagamma or in response to stimulation of muscarinic (m2) G protein-coupled receptors. Signaling from PI3Kgamma to MAPK appears to require a tyrosine kinase, Shc, Grb2, Sos, Ras, and Raf. These findings indicate that PI3Kgamma mediates Gbetagamma-dependent regulation of the MAPK signaling pathway.

687 citations


Journal ArticleDOI
TL;DR: Improved stability and loading capacities were found for amorphous lipid nanoparticles which present the characteristic signals of supercooled melts in high resolution 1 H-NMR, and significant differences between monoacid triglycerides and complex lipids were found.

481 citations


Journal ArticleDOI
04 Dec 1997-Nature
TL;DR: In this paper, the authors studied the response of a Langmuir-Blodgett multilayer film of cadmium arachidate to laser heating by observing changes in the intensity of one Bragg peak for different delays between the perturbing optical pulse and the X-ray probe pulse.
Abstract: The extension of time-resolved X-ray diffraction to the subpicosecond domain is an important challenge, as the nature of chemical reactions and phase transitions is determined by atomic motions on these timescales. An ultimate goal is to study the structure of transient states with a time resolution shorter than the typical period of vibration along a reaction coordinate (around 100 fs). Biological processes that can be initiated optically have been studied extensively by ultrafast infrared, visible and ultraviolet spectroscopy1. But these techniques probe only electronic states, whereas time-resolved crystallography should be able to directly monitor atomic positions. Here we show that changes in the X-ray diffraction pattern from an organic film heated by a laser pulse can be monitored on a timescale of less than a picosecond. We have studied the response of a Langmuir–Blodgett multilayer film of cadmium arachidate to laser heating by observing changes in the intensity of one Bragg peak for different delays between the perturbing optical pulse and the X-ray probe pulse. A strong decrease in intensity is seen within a picosecond of heating, resulting from disorder introduced to the layers of cadmium atoms before thermal expansion of the film (which ultimately leads to its destruction) has time to occur.

396 citations


Journal ArticleDOI
TL;DR: It is suggested that EHE of soft tissue is better regarded as a fully malignant, rather than borderline, vascular neoplasm, albeit the prognosis is better than in conventional angiosarcoma.
Abstract: Epithelioid hemangioendothelioma of soft tissues (EHE) represents a distinct entity with an unpredictable clinical course. We analyzed the clinicopathologic and immunohistochemical features in a series of 30 patients. Patient age range was 16-74 years (median 50); 18 of 30 patients were female. Eight tumors arose in the lower and two in the upper extremities, seven on the trunk, five each in the head/ neck and anogenital regions, two in the mediastinum, and one in the abdomen. Seventeen neoplasms were located in deep soft tissues, nine were subcutaneous or perifascial, and four were dermal; size ranged from 0.4 to 10 cm; in 11 cases the tumor was > 5 cm. Tumors with an infiltrative growth pattern were more common than entirely circumscribed lesions. The tumors were composed histologically of short strands, cords, or small clusters of epithelioid, round, to slightly spindled endothelial cells that formed at least focally, intracellular lumina and were set in a frequently myxohyaline stroma. Thirteen of 30 lesions showed angiocentric growth, which was occlusive in many cases. Immunohistochemically, all cases tested were positive for at least one endothelial marker (CD31, CD34, factor VIII, Ulex europaeus), six of 23 (26%) were positive for cytokeratin, and five of 11 (45%) were positive for alpha-smooth muscle actin. Median follow-up of 36 months (range 2-96) in 24 cases showed local recurrence in three cases and systemic metastases in five cases (21%); four patients (17%) died of tumor. Although more aggressive histologic features (striking nuclear atypia in eight cases, numerous spindled cells in 10, more than two mitoses per 10 high-power fields in nine, and small, more solid angiosarcomalike foci in four cases) tended to be related to poor clinical outcome, there was no clear correlation. Two metastasizing cases showed no histologically atypical features whatever. We suggest that EHE of soft tissue is better regarded as a fully malignant, rather than borderline, vascular neoplasm, albeit the prognosis is better than in conventional angiosarcoma.

360 citations


Journal ArticleDOI
M. Dakna1, T. Anhut1, Tomáš Opatrný1, Ludwig Knöll1, D.-G. Welsch1 
TL;DR: In this paper, a scheme for generating Schrodinger-cat-like states of a single-mode optical field by means of conditional measurement is proposed, where a squeezed vacuum is fed into a beam splitter and counting the photons in one of the output channels, the conditional states in the other output channel exhibit a number of properties similar to those of superpositions of two coherent states with opposite phases.
Abstract: A scheme for generating Schr\"odinger-cat-like states of a single-mode optical field by means of conditional measurement is proposed. Feeding a squeezed vacuum into a beam splitter and counting the photons in one of the output channels, the conditional states in the other output channel exhibit a number of properties that are very similar to those of superpositions of two coherent states with opposite phases. We present analytical and numerical results for the photon-number and quadrature-component distributions of the conditional states and their Wigner and Husimi functions. Further, we discuss the effect of realistic photocounting on the states.

344 citations


Journal ArticleDOI
TL;DR: In this article, the emission spectra of the transition metals Cr, Mn, Fe, Co, Ni, and Cu were measured, employing a single-crystal diffractometer optimized for minimal instrumental broadening.
Abstract: The $K{\ensuremath{\alpha}}_{1,2}$ and $K{\ensuremath{\beta}}_{1,3}$ emission spectra of the $3d$ transition metals Cr, Mn, Fe, Co, Ni, and Cu were measured, employing a single-crystal diffractometer optimized for minimal instrumental broadening. The high-accuracy diffractometer, and the interferometrically calibrated silicon crystal employed ensure absolute wavelengths in the metric scale to a sub-part-per-million accuracy. An accurate analytic representation of each line, obtained by a fit to a minimal set of Lorentzians, is presented. The absolute energies, linewidths, and indices of asymmetry, derived from the data, agree well with previous measurements. So do also the intensity ratios $K{\ensuremath{\alpha}}_{2}/K{\ensuremath{\alpha}}_{1}$ and $K{\ensuremath{\beta}}_{1,3}/K{\ensuremath{\alpha}}_{1,2},$ which are, however, slightly, but consistently, higher than previous values. Possible origins for the observed $Z$-dependent trends are discussed.

335 citations


Journal ArticleDOI
TL;DR: The aim of this paper is to examine the influence of tissue resistivity changes on the neuromagnetic field and the electric scalp potential, using a high-resolution finite element method of the human head with 13 different tissue types.
Abstract: Modeling in magnetoencephalography (MEG) and electroencephalography (EEG) requires knowledge of the in vivo tissue resistivities of the head. The aim of this paper is to examine the influence of tissue resistivity changes on the neuromagnetic field and the electric scalp potential. A high-resolution finite element method (FEM) model (452162 elements, 2-mm resolution) of the human head with 13 different tissue types is employed for this purpose. Our main finding was that the magnetic fields are sensitive to changes in the tissue resistivity in the vicinity of the source. In comparison, the electric surface potentials are sensitive to changes in the tissue resistivity in the vicinity of the source and in the vicinity of the position of the electrodes. The magnitude (strength) of magnetic fields and electric surface potentials is strongly influenced by tissue resistivity changes, while the topography is not as strongly influenced. Therefore, an accurate modeling of magnetic field and electric potential strength requires accurate knowledge of tissue resistivities, while for source localization procedures this knowledge might not be a necessity.

314 citations


Journal ArticleDOI
TL;DR: It is concluded that undesirable splanchnic effects on patients in whom that region is particularly fragile should be considered when using epinephrine for septic shock treatment.
Abstract: ObjectiveTo assess the effects of epinephrine on splanchnic perfusion and splanchnic oxygen uptake in patients with septic shock.DesignProspective, controlled trial.SettingUniversity hospital intensive care unit (ICU).PatientsEight patients with septic shock, according to the criteria of the 1992 Am

291 citations


Journal ArticleDOI
TL;DR: It is shown that laccase‐less mutants of P. cinnabarinus were greatly reduced in their ability to metabolize 14C ring‐labeled DHP, but 14CO2 evolution in these mutant cultures could be restored to levels comparable to those of the wild‐type cultures by addition of purified P.cinnabaranus laccases.

Journal ArticleDOI
TL;DR: The power limitations should be considered during NIR femtosecond microscopy of vital cells and in the design of compact NIR FemTosecond solid-state lasers for two-photon microscopes.
Abstract: The influence of femtosecond near-infrared (NIR) microirradiation on cell vitality and cellular reproduction has been studied. Chinese hamster ovary cells exposed to a highly focused 150-fs scanning beam at 730, 760, and 800 nm (80 MHz, 80-mus pixel dwell time) of /=6 -mW mean power, cells were unable to form clones. They died or became giant cells. Complete cell destruction, including cell fragmentation, occurred at mean powers >10 mW. Cell death was accompanied by intense luminescence in the mitochondrial region. When we consider the diffraction-limited spot size in the submicrometer region, intensities and photon flux densities of 0.8-kW pulses (10-mW mean power) are of the order of terawatts per square centimeter (10(12)W/cm (2)) and 10(32) photons cm(-2) s(-1) , respectively. Extremely high fields may induce destructive intracellular plasma formation. The power limitations should be considered during NIR femtosecond microscopy of vital cells and in the design of compact NIR femtosecond solid-state lasers for two-photon microscopes.

Journal ArticleDOI
TL;DR: In this article, the accuracy, transferability, and plane-wave convergence properties of pseudopotentials for Fe, Co, and Ni in the context of atomic, molecular, and solid calculations were studied.
Abstract: We present a study of the accuracy, transferability, and plane-wave convergence properties of ultrasoft Vanderbilt-type pseudopotentials for Fe, Co, and Ni in the context of atomic, molecular, and solid calculations. Special attention has been given to the magnetic properties of these systems. To go beyond the local-spin-density-approximation, generalized gradient approximations for the exchange-correlation functional have been included. All calculations have been performed using a plane-wave basis set, and we show that ultrasoft pseudopotentials allow -- as expected -- for a considerably lower cutoff energy than standard soft norm-conserving pseudopotentials. Lattice properties show very good agreement with all-electron calculations and experiment, while larger discrepancies exist for magnetic structural energy differences (which however remain smaller than 2 mRy/atom). These differences can be traced back to the frozen core approximation which is implicitly assumed in the construction of the pseudopotentials. More accurate results for the magnetization energies of atomic configurations can be obtained by treating the $3p$ semicore states as valence states.

Journal ArticleDOI
K. Meyer1
TL;DR: In this article, the Raman and infrared spectra of zinc phosphate glasses, xZnO·(1−x)P2O5 with 0≤x≤0.5, and the crystalline compounds, o′-P 2O5, ZnP4O11, α1-, α2-, and β-Zn(PO3)2, were measured.
Abstract: The Raman and infrared spectra of zinc phosphate glasses, xZnO·(1−x)P2O5 with 0≤x≤0.5, and the crystalline compounds, o′-P2O5, ZnP4O11, α1-, α2-, and β-Zn(PO3)2, were measured. An analysis of the vibrational spectra is discussed in comparison with the results of the investigation of the same glasses by 31 P -MAS–NMR spectroscopy and X-ray diffraction. The structure of the zinc phosphate glasses can be described by substructures of the high-temperature modifications of the three crystalline compounds with x=0, 0.33, and 0.5.

Journal ArticleDOI
TL;DR: It is frequently difficult to distinguish patients with systemic infection from those who appear septic but have no bacteriological or clinical evidence of infection, and new parameters are needed to provide an early marker of the infectious etiology of a generalized inflammatory response and allow early diagnosis and the application of more specific therapeutic interventions.
Abstract: Severe infection and sepsis with consecutive multiple organ dysfunction or failure (MODS) are major causes of morbidity and mortality in modern intensive care units [1]. Recent advances in our understanding of the pathogenesis of sepsis have made it clear that uncontrolled infections, whether clinically manifest or occult, are not the only cause of systemic inflammation and organ dysfunction. Other stimuli such as pancreatitis [2], major trauma [3], and burns [4] can also trigger an excessive inflammatory response and lead to MODS. As a result, it is now generally accepted that not all patients displaying the clinical signs of sepsis have an underlying infection. It is therefore frequently difficult to distinguish patients with systemic infection from those who appear septic but have no bacteriological or clinical evidence of infection. Common signs of systemic inflammation such as changes in body temperature, leukocytosis, and tachycardia may have an infectious or noninfectious etiology and are neither ,specific nor sensitive for sepsis. Thus, of 61 patients with sepsis (documented infection and at least two signs of remote organ failure), 35 (57%) presented with leukocytosis, 18 (29%) had leukopenia, and eight (14%) had normal leukocyte counts (unpublished data). Likewise, patients with sepsis may present with fever, hypothermia, or normal body temperature. Bacteriological evidence of infection, although considered a gold standard, may have some drawbacks. Negative blood cultures do not exclude sepsis and multiple samples may be required over extended periods before positive cultures emerge [5]. Furthermore, positive or negative cultures may not develop concurrently with clinical signs of sepsis. Because these common clinical and laboratory parameters lack sensitivity and specificity, others are needed to provide an early marker of the infectious etiology of a generalized inflammatory response and thus allow early diagnosis and the application of more specific therapeutic interventions. Furthermore, new parameters also may help identify subgroups of septic patients who may benefit from proor antiinflammatory therapies. One such parameter, procalcitonin, has recently attracted attention as a possible marker of the systemic inflammatory response to infection.

Journal ArticleDOI
TL;DR: It follows that determining the winner in Carroll's elections is not NP-complete unless the polynomial hierarchy collapses, and the stronger lower bound and upper bound are provided that matches the lower bound.
Abstract: In 1876, Lewis Carroll proposed a voting system in which the winner is the candidate who with the fewest changes in voters' preferences becomes a Condorcet winner—a candidate who beats all other candidates in pairwise majority-rule elections. Bartholdi, Tovey, and Trick provided a lower bound—NP-hardness—on the computational complexity of determining the election winner in Carroll's system. We provide a stronger lower bound and an upper bound that matches our lower bound. In particular, determining the winner in Carroll's system is complete for parallel access to NP, that is, it is complete for Theta_2p for which it becomes the most natural complete problem known. It follows that determining the winner in Carroll's elections is not NP-complete unless the polynomial hierarchy collapses.

Journal ArticleDOI
TL;DR: The data suggest that HERG channel blockade is involved in the arrhythmogenic side effects of haloperidol.
Abstract: 1. The antipsychotic drug haloperidol can induce a marked QT prolongation and polymorphic ventricular arrhythmias. In this study, we expressed several cloned cardiac K+ channels, including the human ether-a-go-go related gene (HERG) channels, in Xenopus oocytes and tested them for their haloperidol sensitivity. 2. Haloperidol had only little effects on the delayed rectifier channels Kv1.1, Kv1.2, Kv1.5 and IsK, the A-type channel Kv1.4 and the inward rectifier channel Kir2.1 (inhibition < 6% at 3 microM haloperidol). 3. In contrast, haloperidol blocked HERG channels potently with an IC50 value of approximately 1 microM. Reduced haloperidol, the primary metabolite of haloperidol, produced a block with an IC50 value of 2.6 microM. 4. Haloperidol block was use- and voltage-dependent, suggesting that it binds preferentially to either open or inactivated HERG channels. As haloperidol increased the degree and rate of HERG inactivation, binding to inactivated HERG channels is suggested. 5. The channel mutant HERG S631A has been shown to exhibit greatly reduced C-type inactivation which occurs only at potentials greater than 0 mV. Haloperidol block of HERG S631A at 0 mV was four fold weaker than for HERG wild-type channels. Haloperidol affinity for HERG S631A was increased four fold at +40 mV compared to 0 mV. 6. In summary, the data suggest that HERG channel blockade is involved in the arrhythmogenic side effects of haloperidol. The mechanism of haloperidol block involves binding to inactivated HERG channels.

Journal ArticleDOI
TL;DR: SFT represents a distinct neoplasm that should be included in the differential diagnosis of spindle-cell neoplasms in soft tissue, nasal cavity and nasopharynx, urinary bladder, and prostate, and strict diagnostic criteria are necessary to avoid overdiagnosis or confusion with more aggressive neoplasts in these locations.
Abstract: The clinicopathological features of 12 extraserosal solitary fibrous tumours (SFT) are described. The age of the patients ranged from 18 to 72 years (mean: 48.2 years; median: 54 years); 5 were female patients. Seven lesions arose in soft tissue (5 in perifascial, and 1 each in subcutaneous and intramuscular tissues). They were situated in the groin (2 cases) and the neck, right buttock, left scapula, upper arm, and anterior abdominal wall (1 case each). One polypoid lesion was seen in in the nasal cavity and 1 in the nasopharynx; 2 neoplasms arose in the urinary bladder and 1 was located in the prostate and periprostatic tissue. Nine lesions were excised; in 1 patient wide excision was performed and in 2 patients, transurethral resection. Limited follow-up of 3 cases revealed a benign clinical course. The size of the neoplasms ranged from 1.7 cm to 20.0 cm (mean: 5.4 cm; median: 3.5 cm). Histologically, the neoplasms were well circumscribed and composed of cytologically bland spindle cells arranged without an obvious pattern; focally storiform or fascicular growth patterns were seen. Tumour cells were separated by thick bands of collagen demonstrating foci of keloid-like hyalinization. Prominent vascularity showing a haemangiopericytoma-like vascular pattern and vessels with thick, hyalinized vessel walls were seen in all cases. Increased mitotic activity was noted in 2 soft tissue cases (4-6 mitoses in 10 high-power fields); the other cases showed fewer than 2 mitotic figures in 10 highpower fields. Immunohistochemically, all cases tested stained positively for vimentin, CD34 and CD99, and 2 cases showed focal myofibroblastic differentiation. Two cases examined ultrastructurally showed a fibroblastic phenotype; focally pinocytic vesicles and microfilaments were identified. SFT represents a distinct neoplasm that should be included in the differential diagnosis of spindle-cell neoplasms in soft tissue, nasal cavity and nasopharynx, urinary bladder, and prostate. Strict diagnostic criteria are necessary to avoid overdiagnosis or confusion with more aggressive neoplasms in these locations.

Journal ArticleDOI
TL;DR: There is a growing interest in CLA, considered to be beneficial in prevention of carcinogenesis, and its percentage in milk products can be increased through a suitable dietary regimen.


Journal ArticleDOI
TL;DR: The data unambiguously demonstrate that the streptococcal enzyme is a virulence factor, and thereby provide additional evidence that microbial cysteine proteases are critical in host-pathogen interactions.
Abstract: Cysteine proteases have been implicated as important virulence factors in a wide range of prokaryotic and eukaryotic pathogens, but little direct evidence has been presented to support this notion. Virtually all strains of the human bacterial pathogen Streptococcus pyogenes express a highly conserved extracellular cysteine protease known as streptococcal pyrogenic exotoxin B (SpeB). Two sets of isogenic strains deficient in SpeB cysteine protease activity were constructed by integrational mutagenesis using nonreplicating recombinant plasmids containing a truncated segment of the speB gene. Immunoblot analyses and enzyme assays confirmed that the mutant derivatives were deficient in expression of enzymatically active SpeB cysteine protease. To test the hypothesis that the cysteine protease participates in host mortality, we assessed the ability of serotype M3 and M49 wild-type strains and isogenic protease-negative mutants to cause death in outbred mice after intraperitoneal inoculation. Compared to wild-type parental organisms, the serotype M3 speB mutant lost virtually all ability to cause mouse death (P < 0.00001), and similarly, the virulence of the M49 mutant was detrimentally altered (P < 0.005). The data unambiguously demonstrate that the streptococcal enzyme is a virulence factor, and thereby provide additional evidence that microbial cysteine proteases are critical in host-pathogen interactions.

Journal ArticleDOI
TL;DR: The understanding of these processes and the sequence of events leading to pleural loculation, pleural adhesion or repair are likely to provide the basis for early therapeutic intervention and reduce pleural-associated morbidity.
Abstract: Although infectious, inflammatory and neoplastic diseases frequently involve the pleural space and walls, little is known about the immunological and molecular mechanisms underlying pleural disorders. This article provides an overview of recent insights into immunobiological processes likely to play a role in the pathogenesis of pleural disorders. Pleural involvement in certain diseases is associated with the infiltration of a number of different types of immune cells, such as neutrophils, eosinophils or lymphocytes, in various proportions depending on both the course and the aetiology of the underlying disease. In addition to infiltrating cells, mesothelial cells have been demonstrated to actively participate in pleural inflammation via release of various mediators and proteins, including platelet-derived growth factor (PDGF), interleukin-8, monocyte chemotactic peptide (MCP-1), nitric oxide (NO), collagen, antioxidant enzymes and the plasminogen activation inhibitor (PAI). Furthermore, several inflammatory mediators have been detected at increased concentrations within pleural effusions, including lipid mediators, cytokines and proteins (adenosine deaminase, lysosyme, eosinophil-derived cationic proteins, and products of the coagulation cascade). The presence of these mediators underline the concept of pleural inflammation, and certain cytokines seem to characterize a specific aetiology of pleurisy. The understanding of these processes and the sequence of events leading to pleural loculation, pleural adhesion or repair are likely to provide the basis for early therapeutic intervention and reduce pleural-associated morbidity.

Journal ArticleDOI
TL;DR: Investigations of highly efficient grating couplers for polymer slab and strip waveguides fabricated by electron-beam lithography are reported and a focusing blazed grating that couples the light with an efficiency of 42% into a polymer strip waveguide is reported.
Abstract: Investigations of highly efficient grating couplers for polymer slab and strip waveguides fabricated by electron-beam lithography are reported A maximum input efficiency of 67% is achieved The electron-beam direct-writing technique allows one to replicate the original gratings into polymer substrates by embossing An all-polymeric optical chip with efficient grating couplers is demonstrated Waveguide grating couplers with blazed profile and variable grating depth are investigated Thus, the intensity distribution of the outcoupled light is matched to a Gaussian-like profile A focusing blazed grating that couples the light with an efficiency of 42% into a polymer strip waveguide is reported A curvature correction of the grating lines allows one to improve the focusing properties

Journal ArticleDOI
TL;DR: A total of 12 placebo-controlled trials with hypericum extracts were performed and in comparison with synthetic antidepressants, a similar reduction of depressive symptomatology was seen, although the comparators were not adequately dosed.
Abstract: In Germany, hypericum extracts are among the most widely prescribed antidepressants. Additionally, many preparations of St. John's wort are sold on the free market and one extract is even the best selling antidepressant in the country. In contrast to synthetic antidepressants, the approval procedures are not so strict, which implies that the pharmaceutical industry is not forced to conduct clinical trials suitable for licensing. Nevertheless, numerous studies on hypericum extracts including depressed patients have been published in the last 20 years. The purpose of this paper is to review these investigations in respect of methodological considerations and to draw conclusions pertaining to the proof of antidepressant efficacy. To this effect, a computer-assisted literature research was performed and manufacturers were asked to supply the author with study results. A total of 12 placebo-controlled trials with hypericum extracts were performed, mostly with positive results. Also in comparison with synthetic antidepressants (3 studies published), a similar reduction of depressive symptomatology was seen, although the comparators were not adequately dosed. No trials in severely depressed patients have been published yet. Since most studies on hypericum have methodological flaws, further studies are warranted.

Journal ArticleDOI
TL;DR: Under the assumption that the simulated PET images embody the salient features of real PET images with respect to coreg registration, this study shows that the routines examined reliably solve the MRI to PET coregistration problem.

Journal ArticleDOI
TL;DR: It is reported for the first time, using two different noninvasive methods, that peripheral, mere motor deefferentation is a sufficient stimulus for reorganizational changes in the healthy adult human cortex.
Abstract: Possible changes in the organization of the cortex in patients with facial palsy, serving as a model of peripheral motor deefferentation, were investigated by using transcranial magnetic stimulation (TMS) and positron emission tomography (PET). With TMS, the size of the area producing muscle-evoked potentials (MEPs) of the abductor pollicis brevis muscle, the sum of MEP amplitudes within this area, and the volume over the mapping area were compared between both hemispheres in 8 patients. With PET, increases in regional cerebral blood flow, measured with the standard H 2 15 O 2 bolus injection technique, were compared between 6 patients and 6 healthy volunteers during sequential finger opposition. Patients moved the hand ipsilateral to the facial palsy, the control subjects the right hand. Of 9 patients in total, 5 participated in both experiments. With both methods, an enlargement of the hand field contralateral to the facial palsy was found, extending in a lateral direction, into the site of the presumed face area. The PET data showed that the enlargement of the hand field in the somatosensory cortex (SMC) is part of a widespread cortical reorganization, including the ipsilateral SMC and bilateral secondary motor and sensory areas. We report for the first time, using two different noninvasive methods, that peripheral, mere motor deefferentation is a sufficient stimulus for reorganizational changes in the healthy adult human cortex.

Journal ArticleDOI
TL;DR: Growth on wheat straw and beech wood led to increased values for both extra- and intracellular laccase activities, based on fungal dry weight, in comparison with growth on glucose.
Abstract: Trametes versicolor was shown to produce extracellular laccase during surface cultivation on glucose, wheat straw and beech wood. Growth on both wheat straw and beech wood led to an increase as high as 3.5-fold in extracellular laccase activity, in comparison with growth on glucose. The corresponding yields in fungal biomass reached only about 20% of the value obtained on glucose. Manganese peroxidase activity␣appeared during growth on wheat straw and beech wood. Mycelia grown on glucose, wheat straw and beech wood also showed intracellular laccase activities, monitored with 2,6-dimethoxyphenol, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 4-hydroxy-3,5-dimethoxybenzaldehyde azine (syringaldazine) and 3,4-dihydroxyphenylalanine (l-DOPA). Assaying intracellular laccase with 2,6-dimethoxyphenol, syringaldazine and l-DOPA showed the maximum oxidation rates to be at pH values different from those producing maximum oxidation rates with extracellular laccase. In each case most of the total laccase activity was recovered from the culture filtrates. Growth on wheat straw and beech wood led to increased values for both extra- and intracellular laccase activities, based on fungal dry weight, in comparison with growth on glucose.

Journal ArticleDOI
TL;DR: Approaches to the gas chromatographic enantiomer separation of chiral organchlorines (alpha-hexachlorocyclohexane, cis- and trans-chlordane, heptachlor, heptonachlorepoxide, oxychlordanes, o,p'-DDT, compounds of technical toxaphene and stable atropisomeric polychlorinated biphenyls) are reviewed.

Journal ArticleDOI
TL;DR: Kovalenko et al. as mentioned in this paper investigated the mechanism of action of AG1296, a potent and specific inhibitor of the platelet-derived growth factor (PDGF) receptor tyrosine kinase.
Abstract: The mechanism of action of AG1296, a potent and specific inhibitor of the platelet-derived growth factor (PDGF) receptor tyrosine kinase [Kovalenko, M, Gazit, A, Bohmer, A, Rorsman, Ch, Ronnstrand, L, Heldin, C-H, Waltenberger, J, Bohmer, F D, & Levitzki, A (1994) Cancer Res 54, 6106-6114] was investigated This quinoxalin-type tyrphostin neither interferes with PDGF-BB binding to the PDGF beta-receptor nor has any effect on receptor dimerization Kinetic analysis of the inhibition was carried out using a synthetic peptide substrate (KY751) corresponding to the sequence around tyrosine 751 autophosphorylation site of the PDGF receptor It revealed purely competitive inhibition vis-a-vis ATP, mixed competitive inhibition vis-a-vis the peptide substrate for the non-activated receptor, and mixed competitive inhibition vis-a-vis both substrates for the activated receptor Thus, the type of inhibition apparently changes upon receptor activation, indicating conformational changes at the ATP-binding site The high degree of selectivity for the tyrphostin AG1296 might result from the complex type of interaction with the active center of the receptor as revealed by the kinetic analysis Dose-response curves for inhibition of the phosphorylation of individual autophosphorylation sites of the PDGF beta-receptor by AG1296 were different, phosphorylation of tyrosine 857 being the most susceptible to inhibition Thus, phosphorylation of tyrosine 857 in the PDGF receptor kinase domain seems dispensable for partial kinase activation The findings are discussed in relation to current models of receptor tyrosine kinase activation

Journal ArticleDOI
TL;DR: C cerebral activation was assessed by means of functional magnetic resonance imaging (fMRI), and a lack of activation in the right prefrontal cortex and--as a trend--an increased left temporal activity during execution of the WCST was noted compared to controls.
Abstract: It has been demonstrated by single photon emission computed tomography (SPECT) and positron emission tomography (PET) that frontal brain regions are stimulated during performance of the Wisconsin Card Sorting Test (WCST). The WCST is also regarded as one of the standard tests for the assessment of frontal activity in brain imaging studies of schizophrenia. In this study cerebral activation was assessed by means of functional magnetic resonance imaging (fMRI). In healthy volunteers WCST stimulation resulted in a right lateralized frontal activation. In 13 chronic schizophrenics on stable neuroleptic medication, a lack of activation in the right prefrontal cortex and — as a trend — an increased left temporal activity during execution of the WCST was noted compared to controls. Since a one-slice technique was used, no information about the activation pattern in adjacent brain regions was obtained. However, as fMRI possesses a superior spatial resolution compared to SPECT and PET, the anatomical localization of the activation effect in the measured slice can be defined more precisely. Beside these methodological considerations, the results are discussed in relation to prior findings of a reduced ability of schizophrenics to coordinate cerebral function.