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Showing papers by "Ludwig Maximilian University of Munich published in 1997"


Journal ArticleDOI
01 Jan 1997-Brain
TL;DR: Using functional magnetic resonance imaging (fMRI) it is concluded that neural elements involved in motor hand function are located in a characteristic 'precentral knob' which is a reliable landmark for identifying the precentral gyrus under normal and pathological conditions.
Abstract: Using functional magnetic resonance imaging (fMRI) we have evaluated the anatomical location of the motor hand area. The segment of the precentral gyrus that most often contained motor hand function was a knob-like structure, that is shaped like an omega or epsilon in the axial plane and like a hook in the sagittal plane. On the cortical surface of cadaver specimens this precentral knob corresponded precisely to the characteristic 'middle knee' of the central sulcus that has been described by various anatomists in the last century. We were then able to show that this knob is a reliable landmark for identifying the precentral gyrus directly. We therefore conclude that neural elements involved in motor hand function are located in a characteristic 'precentral knob' which is a reliable landmark for identifying the precentral gyrus under normal and pathological conditions. It faces and forms the 'middle knee' of the central sulcus, is located just at the cross point between the precentral sulcus and the central sulcus, and is therefore also visible on the cortical surface.

1,685 citations


Journal ArticleDOI
TL;DR: The chemistry of N-heterocyclic carbenes has long been limited to metal coordination compounds derived from azolium precursors, a development that was started by Ofele and Wanzlick in 1968 as discussed by the authors.
Abstract: The chemistry of N-heterocyclic carbenes has long been limited to metal coordination compounds derived from azolium precursors, a development that was started by Ofele and Wanzlick in 1968. Since free carbenes are now available through the work of Arduengo (1991), a renaissance in this little-recognized area of chemistry has occurred. A leading motive is the advantages of N-heterocyclic carbenes as ligands in organometallic catalysts, where they extend the scope of application reached by phosphanes (functionalized, chiral, water-soluble, and immobilized derivatives). The present review summarizes the state of the art with regard to synthesis, structure, bonding theory, metal coordination chemistry, and catalysis. Chelating, functionalized, chiral, and immobilized ligands can be generated and attached to metal centers in straightforward procedures under mild conditions. A wealth of new chemistry is thus opened. It is also shown how carbenes derived from imidazoles and triazoles behave as ligands in catalysis. It is reasonable to assume that N-heterocyclic carbenes surpass the ubiquitous phosphanes as ligands in a number of organometallic catalytic reactions.

1,479 citations


Journal ArticleDOI
TL;DR: Gollwitzer et al. as mentioned in this paper explored the theoretical distinction between goal intentions and implementation intentions by assessing the completion rate of various goal projects and found that difficult goal intentions were completed about 3 times more often when participants had furnished them with implementation intentions.
Abstract: The theoretical distinction between goal intentions ("I intend to achieve -c") and implementation intentions ("I intend to perform goal-directed behavior y when I encounter situation z"; P. M. Gollwitzer, 1993) is explored by assessing the completion rate of various goal projects. In correlational Study 1, difficult goal intentions were completed about 3 times more often when participants had furnished them with implementation intentions. In experimental Study 2, all participants were assigned the same difficult goal intention, and half were instructed to form implementation intentions. The beneficial effects of implementatio n intentions paralleled diose of Study 1. In experimental Study 3, implementatio n intentions were observed to facilitate the immediate initiation of goaldirected action when the intended opportunity was encountered. Implementation intentions are interpreted to be powerful self-regulatory tools for overcoming the typical obstacles associated with the initiation of goal-directed actions. Whether people meet their goals depends on both how goal content is framed and how people regulate the respective goaldirected activities (Gollwitzer & Moskowitz, 1996). Content theories focus on the thematic properties of set goals and how these affect the regulation of goal pursuit and actual goal achievement. Such theories attempt to explain differences in goal-directed behaviors in terms of what is specified as the goal by the individual, as the content characteristics of the goal are expected to affect a person's successful goal pursuit. Goal content has been considered both in terms of the different needs on which it is based (e.g., autonomy needs vs. materialistic needs; Deci & Ryan, 1991; Kasser & Ryan, 1994) as well as in terms of implicit theories (e.g., entity theories vs, incremental theories

1,260 citations


Journal ArticleDOI
11 Jul 1997-Cell
TL;DR: In this article, DNA was extracted from a Neandertal-type specimen found in 1856 in western Germany and a hitherto unknown mt-DNA sequence was determined by sequencing clones from short overlapping PCR products.

1,207 citations


Journal ArticleDOI
TL;DR: The majority of patients were constitutionally small, with 36% of patients below the 3rd centile for either height or weight parameters, and the majority of surviving patients were developmentally normal or had only mild learning problems.
Abstract: We present clinical data on 558 patients with deletions within the DiGeorge syndrome critical region of chromosome 22q11. Twenty-eight percent of the cases where parents had been tested had inherited deletions, with a marked excess of maternally inherited deletions (maternal 61, paternal 18). Eight percent of the patients had died, over half of these within a month of birth and the majority within 6 months. All but one of the deaths were the result of congenital heart disease. Clinically significant immunological problems were very uncommon. Nine percent of patients had cleft palate and 32% had velopharyngeal insufficiency, 60% of patients were hypocalcaemic, 75% of patients had cardiac problems, and 36% of patients who had abdominal ultrasound had a renal abnormality. Sixty-two percent of surviving patients were developmentally normal or had only mild learning problems. The majority of patients were constitutionally small, with 36% of patients below the 3rd centile for either height or weight parameters.

1,087 citations


Journal ArticleDOI
28 Feb 1997-Science
TL;DR: Dextran filaments linked to a gold surface were probed with the atomic force microscope tip by vertical stretching and the conformational change was found to be reversible and was corroborated by molecular dynamics calculations.
Abstract: Recent developments in piconewton instrumentation allow the manipulation of single molecules and measurements of intermolecular as well as intramolecular forces. Dextran filaments linked to a gold surface were probed with the atomic force microscope tip by vertical stretching. At low forces the deformation of dextran was found to be dominated by entropic forces and can be described by the Langevin function with a 6 angstrom Kuhn length. At elevated forces the strand elongation was governed by a twist of bond angles. At higher forces the dextran filaments underwent a distinct conformational change. The polymer stiffened and the segment elasticity was dominated by the bending of bond angles. The conformational change was found to be reversible and was corroborated by molecular dynamics calculations.

1,079 citations


Journal ArticleDOI
TL;DR: Molecular chaperones in the matrix exert multiple functions in translocation, sorting, folding, and assembly of newly imported proteins.
Abstract: Mitochondria import many hundreds of different proteins that are encoded by nuclear genes These proteins are targeted to the mitochondria, translocated through the mitochondrial membranes, and sorted to the different mitochondrial subcompartments Separate translocases in the mitochondrial outer membrane (TOM complex) and in the inner membrane (TIM complex) facilitate recognition of preproteins and transport across the two membranes Factors in the cytosol assist in targeting of preproteins Protein components in the matrix partake in energetically driving translocation in a reaction that depends on the membrane potential and matrix-ATP Molecular chaperones in the matrix exert multiple functions in translocation, sorting, folding, and assembly of newly imported proteins

1,079 citations


Journal ArticleDOI
TL;DR: A protocol that allows CGH to chips consisting of glass slides with immobilized target DNAs arrayed in small spots to be developed, providing a basis for the development of automated diagnostic procedures with biochips designed to meet clinical needs.
Abstract: Comparative genomic hybridization (CGH) to metaphase chromosomes has been widely used for the genome-wide screening of genomic imbalances in tumor cells. Substitution of the chromosome targets by a matrix consisting of an ordered set of defined nucleic acid target sequences would greatly enhance the resolution and simplify the analysis procedure, both of which are prerequisites for a broad application of CGH as a diagnostic tool. However, hybridization of whole genomic human DNA to immobilized single-copy DNA fragments with complexities below the megabase pair level has been hampered by the low probability of specific binding because of the high probe complexity. We developed a protocol that allows CGH to chips consisting of glass slides with immobilized target DNAs arrayed in small spots. High-copy-number amplifications contained in tumor cells were rapidly scored by use of target DNAs as small as a cosmid. Low-copy-number gains and losses were identified reliably by their ratios by use of chromosome-specific DNA libraries or genomic fragments as small as 75 kb cloned in PI or PAC vectors as targets, thus greatly improving the resolution achievable by chromosomal CGH. The ratios obtained for the same chromosomal imbalance by matrix CGH and by chromosomal CGH corresponded very well. The new matrix CGH protocol provides a basis for the development of automated diagnostic procedures with biochips designed to meet clinical needs.

1,062 citations


Journal ArticleDOI
TL;DR: It is found insufficient evidence from these studies that homoeopathy is clearly efficacious for any single clinical condition, and the hypothesis that the clinical effects of homoeopathic remedies are completely due to placebo is not compatible.

910 citations


Journal ArticleDOI
TL;DR: In this paper, the authors derive the optimal incentive scheme for a manager as a function of the competitiveness of the environment in which his firm operates, and show that increased competition reduces the profits of a firm.
Abstract: are imperfectly competitive, Leibenstein (1966) claims that there may be a substantial amount of "X-inefficiency", where X-inefficiency measures the degree to which actual profits depart from the maximum of profits that could be obtained if all operations in the firm were carried out at minimal costs. He offers empirical evidence from case studies showing that the welfare loss due to organizational slack is of an order of magnitude bigger than the welfare loss due to monopolistic price distortions on imperfectly competitive markets.' These results support the common presumption that increasing competition reduces organizational and in particular managerial slack. However, this early literature does not offer a theoretical explanation for the link between competition and managerial incentives. In particular, it ignores the fact that managerial incentives can be affected by the design of an incentive scheme. In this paper I derive the optimal incentive scheme for a manager as a function of the competitiveness of the environment in which his firm operates. The basic impact of increased competition is that it reduces the profits of a firm. This has two effects in the model. First, if a firm has high costs, then the reduction of profits may be sufficient to render the firm unprofitable, so the probability that it has to be liquidated goes up. This unambiguously induces the manager of the firm to work harder for a cost reduction in order to avoid liquidation and to keep his job. Second, the reduction in profits may affect

905 citations


Journal ArticleDOI
TL;DR: The trend toward an increased risk over time after transplantation and the greater risk among younger patients indicate the need for life-long surveillance.
Abstract: Background The late effects of bone marrow transplantation, including cancer, need to be determined in a large population at risk. Methods We studied 19,229 patients who received allogeneic transplants (97.2 percent) or syngeneic transplants (2.8 percent) between 1964 and 1992 at 235 centers to evaluate the risk of the development of a new solid cancer. Risk factors relating to the patient, the transplant, and the course after transplantation were evaluated. Results The transplant recipients were at significantly higher risk of new solid cancers than the general population (observed cases, 80; ratio of observed to expected cases, 2.7; P<0.001). The risk was 8.3 times as high as expected among those who survived 10 or more years after transplantation. The cumulative incidence rate was 2.2 percent (95 percent confidence interval, 1.5 to 3.0 percent) at 10 years and 6.7 percent (95 percent confidence interval, 3.7 to 9.6 percent) at 15 years. The risk was significantly elevated (P<0.05) for malignant melanom...

Journal ArticleDOI
TL;DR: A graphical method, likelihood-mapping, is introduced, to visualize the phylogenetic content of a set of aligned sequences, based on an analysis of the maximum likelihoods for the three fully resolved tree topologies that can be computed for four sequences.
Abstract: We introduce a graphical method, likelihood-mapping, to visualize the phylogenetic content of a set of aligned sequences. The method is based on an analysis of the maximum likelihoods for the three fully resolved tree topologies that can be computed for four sequences. The three likelihoods are represented as one point inside an equilateral triangle. The triangle is partitioned in different regions. One region represents star-like evolution, three regions represent a well-resolved phylogeny, and three regions reflect the situation where it is difficult to distinguish between two of the three trees. The location of the likelihoods in the triangle defines the mode of sequence evolution. If n sequences are analyzed, then the likelihoods for each subset of four sequences are mapped onto the triangle. The resulting distribution of points shows whether the data are suitable for a phylogenetic reconstruction or not.

Journal ArticleDOI
TL;DR: C Cyanosis, operative experience of the surgeon and an RV outflow tract patch influence long-term outcome after repair of TOF in older children, and thus heart monitoring should be intensified.

Journal ArticleDOI
TL;DR: The role of modelling in economic evaluation is explored by discussing, with examples, the uses of models and some suggestions for good modelling practice are made.
Abstract: The role of modelling in economic evaluation is explored by discussing, with examples, the uses of models. The expanded use of pragmatic clinical trials as an alternative to models is discussed. Some suggestions for good modelling practice are made.

Journal ArticleDOI
TL;DR: Individual differences in learning from worked-out examples with respect to the quality of self-explanations were found to be multidimensional and successful learners tended to employ more prlnciplebased explanations, more explication of operator-goal combinations, and more anticipative reasoning.

Journal ArticleDOI
TL;DR: RFLPs, AFLPs, RAPDs and SSRs were used to determine the genetic relationships among 18 cultivated barley accessions and the results compared to pedigree relationships where these were available and the choice of appropriate technology for different aspects of germplasm evaluation is discussed.
Abstract: RFLPs, AFLPs, RAPDs and SSRs were used to determine the genetic relationships among 18 cultivated barley accessions and the results compared to pedigree relationships where these were available. All of the approaches were able to uniquely fingerprint each of the accessions. The four assays differed in the amount of polymorphism detected. For example, all 13 SSR primers were polymorphic, with an average of 5.7 alleles per primer set, while nearly 54% of the fragments generated using AFLPs were monomorphic. The highest diversity index was observed for AFLPs (0.937) and the lowest for RFLP (0.322). Principal co-ordinate analysis (PCoA) clearly separated the spring types from the winter types using RFLP and AFLP data with the two-row winter types forming an intermediate group. Only a small group of spring types clustered together using SSR data with the two-row and six-row winter varieties more widely dispersed. Direct comparisons between genetic similarity (GS) estimates revealed by each of the assays were measured by a number of approaches. Spearman rank correlation ranked over 70% of the pairwise comparisons between AFLPs and RFLPs in the same order. SSRs had the lowest values when compared to the other three assays. These results are discussed in terms of the choice of appropriate technology for different aspects of germplasm evaluation.

Journal ArticleDOI
TL;DR: Femtosecond pulses with center wavelengths between 470 and 750 nm are generated in a single-stage type I BBO optical parametric amplifier pumped by a frequency-doubled 1-kHz Ti:sapphire amplifier.
Abstract: Femtosecond pulses with center wavelengths between 470 and 750 nm are generated in a single-stage type I BBO optical parametric amplifier pumped by a frequency-doubled 1-kHz Ti:sapphire amplifier. A high-quality white-light continuum is used as the seed. Pulse durations as short as 16 fs and pulse energies of as much as 11 microJ are observed. The quantum efficiency is ~25% for both 7- and 40-microJ pump pulses. This unique combination of ultrashort pulse duration and high conversion is made possible by noncollinear phase matching that permits a sufficiently large amplification bandwidth. Simultaneously the group velocities of the signal and the idler are effectively matched. As a result widely tunable sub-20-fs pulses can be generated in a nonlinear crystal as thick as 2 mm.

Journal ArticleDOI
TL;DR: A lack of correlation between microvascular and epicardial vessel disease suggests discordant manifestations and progression of CAV, and methods to augment endogenous nitric oxide bioavailability as well as newer immunosuppressive regimens may be protective.
Abstract: Cardiac allograft vasculopathy (CAV) remains a troublesome long-term complication of heart transplantation. It is manifested by a unique and unusually accelerated form of coronary disease affecting both intramural and epicardial coronary arteries and veins. CAV is characterized by vascular injury induced by a variety of noxious stimuli, including the immune system response to the allograft, ischemia-reperfusion injury, viral infection, immunosuppressive drugs, and classic risk factors such as hyperlipidemia, insulin resistance, and hypertension. The obstructive vascular lesions are thought to progress through repetitive endothelial injury followed by repair response. The role of major histocompatibility complex donor-recipient differences in the pathogenesis of CAV has not yet been completely elucidated. Intracoronary ultrasound studies reveal a dual morphology with donor-transmitted or de novo focal, noncircumferential plaques in proximal segments and/or a diffuse, concentric pattern observed in distal segments. A lack of correlation between microvascular and epicardial vessel disease suggests discordant manifestations and progression of CAV. Apoptosis and loss of functional vascular remodeling have to be considered as important mediators of clinically relevant CAV. Strategies for blocking T-cell costimulation and expression of adhesion molecules may help prevent chronic rejection in clinical transplantation. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and antiproliferative drugs may slow progression of CAV by various effects. Methods to augment endogenous nitric oxide bioavailability as well as newer immunosuppressive regimens may be protective. Balloon angioplasty has a limited role in the treatment of focal lesions. Experiences with coronary stenting, coronary artery bypass grafting, and transmyocardial laser revascularization are limited. Retransplantation has a worse outcome than initial transplantation.


Journal ArticleDOI
TL;DR: The complete construction of a mutant herpesvirus genome can now be carried out in a controlled manner prior to the reconstitution of infectious progeny.
Abstract: A strategy for cloning and mutagenesis of an infectious herpesvirus genome is described. The mouse cytomegalovirus genome was cloned and maintained as a 230 kb bacterial artificial chromosome (BAC) in E. coli. Transfection of the BAC plasmid into eukaryotic cells led to a productive virus infection. The feasibility to introduce targeted mutations into the BAC cloned virus genome was shown by mutation of the immediate-early 1 gene and generation of a mutant virus. Thus, the complete construction of a mutant herpesvirus genome can now be carried out in a controlled manner prior to the reconstitution of infectious progeny. The described approach should be generally applicable to the mutagenesis of genomes of other large DNA viruses.

Journal ArticleDOI
01 Oct 1997-Stroke
TL;DR: Blood concentrations of S-100 protein periodically in the first 10 days after cerebral infarction helps to predict infarct volume and the long-term neurological outcome more accurately than periodic measurements of blood concentrations of NSE.
Abstract: Background and Purpose Better techniques are needed to monitor infarction volume and predict neurological outcome after ischemic brain infarction. We evaluated the usefulness of serial measurements of S-100 protein versus neuron-specific enolase (NSE) in blood samples from patients with acute stroke. Methods Using nonisotopic sandwich immunoassays, we measured plasma concentrations of S-100 protein and NSE on admission and on days 3, 4, 7, and 14 after infarction in 44 patients (age range, 22 to 86 years; mean age, 65.1 years; 12 female, 32 male). Infarct volume was measured by volumetric CT on day 4 after ictus, and clinical outcome was assessed at discharge from hospital with the Activities of Daily Living Scale and 6 months after infarction with the Glasgow Outcome Scale. Results Peak blood levels of S-100 protein were found on day 2.5±1.3, and peak levels of NSE were found on day 1.9±0.8 after infarction. Peak plasma levels of S-100 protein correlated well with infarct volume (r=.75, P<.001) and with ...

Journal ArticleDOI
TL;DR: The reduction ofCD11b expression and inhibition of CD11b-dependent monocyte adhesion to endothelium may crucially contribute to the clinical benefit of HMG-CoA reductase inhibitors in CHD, independent of cholesterol-lowering effects.

Journal ArticleDOI
TL;DR: The strong correlation between elevated uPA and/or PAI-1 values in primary cancer tissues and the tumor invasion/ metastasis capacity of cancer cells, proteolytic factors have been selected as targets for therapy.
Abstract: Extravasation and intravasation of solid malignant tumors is controlled by attachment of tumor cells to components of the basement membrane and the extracellular matrix, by local proteolysis and tumor cell migration. Strong clinical and experimental evidence has accumulated that the tumor-associated serine protease plasmin, its activator uPA (urokinase-type plasminogen activator), the receptor uPA-R (CD87), and the inhibitors PAI-1 and PAI-2 are linked to cancer invasion and metastasis. In cancer, increase of uPA, uPA-R, and/or PAI-1 is associated with tumor progression and with shortened disease-free and/or overall survival in patients afflicted with malignant solid tumors. uPA and/or its inhibitor PAI-1 appear to be one of the strongest prognostic markers so far described. Strong prognostic value to predict disease recurrence and overall survival has been documented for patients with cancer of the breast, ovary, cervix, endometrium, stomach, colon, lung, bladder, kidney, brain, and soft-tissue. Due to the strong correlation between elevated uPA and/or PAI-1 values in primary cancer tissues and the tumor invasion/ metastasis capacity of cancer cells, proteolytic factors have been selected as targets for therapy. Various very different approaches to interfere with the expression or reactivity of uPA or CD87 at the gene or protein level were successfully tested including antisense oligonucleotides, antibodies, enzyme inhibitors, and recombinant or synthetic uPA and uPA-R analogues.

Journal ArticleDOI
TL;DR: A simplified method for the calculation of mammalian cell survival after charged particle irradiation is presented that is based on the track structure model of Scholz and Kraft, and yields linear-quadratic relations also for heavy ion irradiation.
Abstract: A simplified method for the calculation of mammalian cell survival after charged particle irradiation is presented that is based on the track structure model of Scholz and Kraft [1, 2]. Utilizing a modified linear-quadratic relation for the x-ray survival curve, one finds that the model yields linear-quadratic relations also for heavy ion irradiation. If survival is calculated as a function of specific energy, z, in the cell nucleus--thus reducing the stochastic fluctuations of energy deposition--the increase in slope of the survival curve and therefore the coefficient beta z can be estimated with sufficient accuracy from the initial slope, alpha z. This permits the tabulation of the coefficients alpha z for the particle types and energies of interest, and subsequent fast calculations of survival levels at any point in a mixed particle beam. The complexity of the calculations can thereby be reduced in a wide range of applications, which permits the rapid calculations that are required for treatment planning in heavy ion therapy. The validity of the modified computations is assessed by the comparison with explicit calculations in terms of the original model and with experimental results for track-segment conditions. The model is then used to analyze the influence of beam fragmentation on the biological effect of charged particle beams penetrating to different depths in tissue. In addition, cell-survival rates after neuron irradiation are computed from the slowing-down spectra of secondary charged particles and are compared to experimental observations.

Journal ArticleDOI
TL;DR: It is possible to develop highly selective and active inhibitors of integrins, especially the αv β3 subtype, by the novel procedure of spatial screening and the resulting αvβ3 antagonists exhibit activity in the nanomolar range and suppress tumor-induced angiogenesis (formation of new blood vessels).
Abstract: Cell–cell and cell–matrix interactions play a major role in biology. An important class of surface receptors are the integrins, which exist in a number of subtypes and are involved in many biological processes, for example embryonic development, blood coagulation, osteoporosis, cancer, and regulation of the balance between proliferation and death (apoptosis) of a cell. Therefore, selective inhibition of specific integrin subtypes is of great pharmaceutical interest. It is possible to develop highly selective and active inhibitors of integrins, especially the αvβ3 subtype, by the novel procedure of spatial screening. The resulting αvβ3 antagonists exhibit activity in the nanomolar range and suppress tumor-induced angiogenesis (formation of new blood vessels). Tissues with intact blood vessels are not influenced. This opens a promising new way for cancer therapy.

Journal ArticleDOI
01 Mar 1997-Brain
TL;DR: Whether the loss of phenomenal vision is a necessary consequence of striate cortical destruction and whether this structure is indispensable for conscious sight are much debated questions which need to be tackled experimentally.
Abstract: In man and monkey, absolute cortical blindness is caused by destruction of the optic radiations and/or the primary visual cortex. It is characterized by an absence of any conscious vision, but stimuli presented inside its borders may nevertheless be processed. This unconscious vision includes neuroendocrine, reflexive, indirect and forced-choice responses which are mediated by the visual subsystems that escape the direct cerebral damage and the Ensuring degeneration. While extrastriate cortical areas participate in the mediation of the forced-choice responses, a concomitant striate cortical activation does not seem to be necessary for blindsight. Whether the loss of phenomenal vision is a necessary consequence of striate cortical destruction and whether this structure is indispensable for conscious sight are much debated questions which need to be tackled experimentally.

Proceedings ArticleDOI
01 May 1997
TL;DR: A new cost model for nearest neighbor search in high-dimensional data space is developed which takes boundary effects into account and therefore also works in high dimensions and is applicable to different data distributions and index structures.
Abstract: In this paper, we present a new cost model for nearest neighbor search in high-dimensional data space. We first analyze different nearest neighbor algorithms, present a generalization of an algorithm which has been originally proposed for Quadtrees [13], and show that this algorithm is optimal. Then, we develop a cost model which - in contrast to previous models - takes boundary effects into account and therefore also works in high dimensions. The advantages of our model are in particular: Our model works for data sets with an arbitrary number of dimensions and an arbitrary number of data points, is applicable to different data distributions and index structures, and provides accurate estimates of the expected query execution time. To show the practical relevance and accuracy of our model, we perform a detailed analysis using synthetic and real data. The results of applying our model to Hilbert and X-tree indices show that it provides a good estimation of the query performance, which is considerably better than the estimates by previous models especially for highdimensional data.

Journal ArticleDOI
TL;DR: It is suggested that leukocyte-platelet adhesion contributes to the regulation of inflammatory responses in AMI.
Abstract: Background Activated platelets tether and activate myeloid leukocytes. To investigate the potential relevance of this mechanism in acute myocardial infarction (AMI), we examined cytokine induction by leukocyte-platelet adhesion and the occurrence of leukocyte-platelet conjugates in patients with AMI. Methods and Results We obtained peripheral venous blood samples in 20 patients with AMI before and daily for 5 days after direct percutaneous transluminal coronary angioplasty (PTCA) and in 20 patients undergoing elective PTCA. Throughout the study period, CD41 immunofluorescence of leukocytes (flow cytometry) revealed increased leukocyte-platelet adhesion in patients with AMI compared with control patients (mean±SE of fluorescence [channels] before PTCA: 77±16 versus 35±9; Pequals;.003). In vitro, thrombin-stimulated fixed platelets bound to neutrophils and monocytes. Within 2 hours, this resulted in increased mRNA for interleukin (IL)-1β, IL-8, and monocyte chemoattractant protein (MCP)-1 in unfractionated ...

Journal ArticleDOI
01 May 1997-Brain
TL;DR: This article is a review of some fundamental concepts of immunology and offers a hypothetical scenario for the immunopathogenesis of multiple sclerosis and a critical overview of various immunotherapies relying on modern biotechnology.
Abstract: Based on exciting results in animal models, a number of novel immunotherapies employing biotechnological products, rather than conventional immunosuppressants, are being developed for the treatment of multiple sclerosis. The first part of this article is a review of some fundamental concepts of immunology and offers a hypothetical scenario for the immunopathogenesis of multiple sclerosis. The second part provides a critical overview of various immunotherapies relying on modern biotechnology. For each approach, the underlying immunological principles, experimental and clinical evidence, and foreseeable problems are separately addressed. Thus, it is hoped that this article serves a dual purpose, namely to provide an update on recent advances in immunology, and to serve as a useful source of reference to immunotherapies holding promise for future treatment of multiple sclerosis.

Journal ArticleDOI
TL;DR: In Alzheimer's disease a marked reduction of regional cerebral blood flow and cerebral hemoglobin oxygenation may occur during activation of brain function, probably mainly in degenerating brain areas, such as the parietal cortex.