Showing papers by "University of Vienna published in 1988"

Augmentation of demyelination in rat acute allergic encephalomyelitis by circulating mouse monoclonal antibodies directed against a myelin/oligodendrocyte glycoprotein

Abstract: In this study the authors have developed a model with which can be studied directly the influence of circulating anti-myelin antibody on the clinical and pathologic course of inflammatory T-cell-mediated experimental allergic encephalomyelitis (EAE) in the rat. EAE was induced by passive transfer of either myelin basic protein (MBP)-activated spleen cells derived from sensitized donors or long-term-cultured MBP-specific T-cell lines. At the onset of the disease, monoclonal antibodies against a myelin/oligodendrocyte glycoprotein (MOG) were injected intravenously. This antigen is exposed on the surface of central nervous system myelin and oligodendrocytes. Intravenous injection of the antibody in the course of T-cell-mediated transfer EAE augmented the severity and duration of clinical signs and resulted in the formation of large, confluent demyelinated plaques.

Calculated thermal properties of metals.

Abstract: The thermal properties of the 14 nonmagnetic cubic metals through the 4d transition series are derived from first-principles electronic-structure calculations coupled with a Debye treatment of the vibrating lattice. Debye temperatures and Gr\"uneisen constants are derived from an analysis of the compressional characteristics of rigid-lattice binding curves and are used to define the contribution of the lattice vibrations to the free energy. A minimization of the resulting free energy with respect to volume yields temperature-dependent lattice separations and coefficients of thermal expansion. Theoretical values of cohesive energies, equilibrium lattice separations, bulk moduli, Debye temperatures, Gr\"uneisen constants, and coefficients of thermal expansion are derived directly from computed electronic-structure results. Good agreement with experiment is found for all computed quantities.

Eye-length measurement by interferometry with partially coherent light

Abstract: With a multimode semiconductor laser we have been able to measure the optical length of the eye within a precision of 0.03 mm. A first series of inυiυo measurements of several human beings shows good correlation with the acoustically determined eye length.

Alterations in Nocturnal Serum Melatonin Levels In Humans With Growth and Aging

Abstract: The available data on potential alterations in serum melatonin (MLT) levels during a human lifetime are fragmentary and inconsistent. We, therefore, measured day- and nighttime serum MLT concentrations in 367 subjects (210 males and 157 females), aged 3 days to 90 yr. Blood samples were collected between 0730 and 1000 h and between 2300 and 0100 h. Serum MLT levels were measured by RIA. The mean nighttime serum MLT concentration was low during the first 6 months of life, i.e. 27.3 +/- 5.4 (+/- SE) pg/mL (0.12 +/- 0.02 nmol/L). It then increased to a peak value at 1-3 yr of age [329.5 +/- 42.0 pg/mL; (1.43 +/- 0.18 nmol/L)], and it was considerably lower [62.5 +/- 9.0 pg/mL; (0.27 +/- 0.04 nmol/L)] in individuals aged 15-20 yr. During the following decades serum MLT declined moderately until old age (70-90 yr of age), i.e. 29.2 +/- 6.1 pg/mL (0.13 +/- 0.03 nmol/L). This biphasic MLT decline follows 2 exponential functions with different slopes (from age 1-20 yr: r = -0.56; P less than 0.001; y = 278.7 X e -0.09x; from age 20-90 yr: r = -0.44; P less than 0.001; y = 84.8 X e -0.017x). The decrease in nocturnal serum MLT in children and adolescents (1-20 yr) correlated with the increase in body weight (r = -0.54; P less than 0.001) and body surface area (r = -0.71; P less than 0.001). At a later age (20-90 yr) there was no correlation among these variables. Daytime serum MLT levels were low and no age-related alterations were found. This study revealed major age-related alterations in nocturnal serum MLT levels. The negative correlation between serum MLT and body weight in childhood and adolescence is evidence that expansion of body size is responsible for the huge MLT decrease during that period. The moderate decline at older ages must derive from other factors.

The pedunculopontine nucleus in Parkinson's disease, progressive supranuclear palsy and Alzheimer's disease.

Abstract: Significant loss of neurons in the pedunculopontine nucleus pars compacta (PPNc), a putative cholinergic nucleus involved in modulating somatic motor activities, has been demonstrated in progressive supranuclear palsy (PSP) and Parkinson's disease but not in Alzheimer's disease. A morphometric study of this nucleus was performed in two cases of PSP and in a cohort of cases of Parkinson's disease, Alzheimer's disease, senile dementia of Alzheimer type (SDAT), and age-matched controls. In PSP a significant 60% neuronal loss in PPNc was associated with neurofibrillary tangles in 40 to 64% of the remaining neurons. In Parkinson's disease there was a significant decrease in cell numbers and density by 53 and 51%, respectively, with Lewy bodies involving 6 to 39% of all neurons. In Alzheimer's disease and SDAT, large neurons were reduced by 29 and 33.8%, respectively, with tangles in 9 to 38% of the remaining cells. The selective affection of this putative cholinergic nucleus in PSP and Parkinson's disease appears to be related to motor dysfunctions in these disorders.

A progress report on the status of the COLUMBUS MRCI program system

Abstract: The COLUMBUS program system is a collection of Fortran programs for performing general multireference single- and double-excitation configuration interaction (MRSDCI) wave function optimization based on the graphical unitary group approach. The program system also includes integral generation, SCF and MCSCF orbital optimization, integral transformation, and wave function analysis programs. The original program system was written in 1980 to 1981. Since that time, it has evolved into one of the most popular MRSDCI program systems used in the computational chemistry community. The discussion of this evolution will include the exploitation of efficient matrix-matrix and matrix-vector product computational kernels, the use of generally contracted symmetry-adapted orbital basis sets, general Hamiltonian diagonalization procedures, energy-based internal walk selection, flexible DRT specification, improved coupling-coefficient evaluation methods, coupled-pair functional and multireference CPF capabilities, and density matrix construction. The numerous versions of the program system that are maintained at different sites and on different computers are now in the process of being merged. The source code for this combined version will be made available to the computational chemistry community. The source code for a specific computer may be generated from the source code for another computer by a single pass through a simple filter utility that is included with the program system. The directly supported computers will initially include various models of VAX, Cray, FPS, IBM, CDC, and ETA machines with the addition of other machines shortly thereafter. The ongoing developments of the COLUMBUS system that are discussed include a new method for computing analytic energy gradients for MRSDCI wave functions. This effective-density-matrix based method avoids the “coupled perturbed MCSCF” solutions for each coordinate direction, avoids the transformation of any derivative-integral quantities from the AO to the MO basis, avoids the transformation of the coupling coefficients from the MO to the AO basis, allows a subset of the MCSCF doubly occupied orbitals to be frozen in the CI wave function, and allows the MRSDCI wave function to be generated from general reference CSFs that are not necessarily related to the MCSCF expansion CSFs.

Prevention of Necrotizing Enterocolitis in Low-Birth-Weight Infants by IgA–IgG Feeding

Abstract: In a randomized clinical trial, we evaluated the efficacy of an oral immunoglobulin preparation (73 percent IgA and 26 percent IgG) in reducing the incidence of necrotizing enterocolitis in infants of low birth weight for whom breast milk from their mothers was not available. A total of 434 infants weighing between 800 and 2000 g were eligible for entry in the study. Of these, 255 were withdrawn - 234 during the first week of the study because breast milk from their mothers became available (123 in the treatment group and 111 in the control group), and 21 because of violations of protocol or because breast milk became available after the first week. The duration of follow-up was 28 days. Among the infants for whom breast milk did not become available during the study, there were no cases of necrotizing enterocolitis among the 88 receiving oral IgA-IgG, as compared with six cases among the 91 control infants (P = 0.0143). Of the infants withdrawn from the study, two assigned to the control group had necrotizing enterocolitis. We conclude that the oral administration of IgA-IgG may prevent the development of necrotizing enterocolitis in low-birth-weight infants.

Visitors excite primates in zoos

Abstract: Fifteen species of primate were observed to assess the effects of zoo visitors on their social behavior. When visitors were present primates were less affiliative, more active, but more aggressive. These changes were particularly marked in arboreal monkeys, especially in smaller species, and were reduced by 50% by lowering the height of spectators. Detailed observations of a group of mandrills indicated that with increasing numbers of visitors the monkeys showed a linear increase in attention to visitors, in activity, and in stereotyped behavior. All of these effects are consistent with an interpretation that visitors are a source of stressful excitement rather than of enrichment.

Experimental allergic encephalomyelitis: the balance between encephalitogenic T lymphocytes and demyelinating antibodies determines size and structure of demyelinated lesions.

Abstract: The effect of a circulating monoclonal antibody recognizing an antigen located on the surface of myelin sheaths (myelin/oligodendroglia glycoprotein, MOG) on clinical and histopathological expression of experimental allergic encephalomyelitis (EAE) was tested in a model of EAE passively transferred by monospecific T lymphocytes. Intravenous injection of anti-MOG antibody at the onset of the disease massively augmented clinical impairment as well as primary demyelination. The structure of the CNS lesions depended on the balance between encephalitogenic T cells and anti-MOG antibody: when EAE was induced with high numbers of T cells, circulating anti-MOG antibody resulted in ubiquitous perivenous demyelination in the spinal cord and medulla oblongata. On the contrary, focal confluent demyelinated lesions were observed in animals injected with low numbers of T cells (even as few as 104) and anti-MOG antibody. Our studies, thus, indicate that the formation of inflammatory demyelinating lesions may be due to a synergistic action of cellular and humoral immune mechanisms.

Wells' syndrome is a distinctive disease entity and not a histologic diagnosis

Abstract: Wells' syndrome is a distinctive dermatosis clinically resembling acute cellulitis with solid edema; it resolves spontaneously after weeks or months without residues. Recurrences over many years are common. Light microscopy is characteristic for the disease, with diffuse tissue eosinophilia and marked edema, fibrinoid "flame figures," and palisading microgranuloma. Vasculitis is never found. Eosinophilia of the peripheral blood is a frequent feature. Etiology and pathogenesis are unknown, but the disease has been found to be associated with hematologic disorders in several cases, and recurrences can often be related to infections, arthropod bites, drug administration, or surgery. The diagnosis of Wells' syndrome should be based on the typical clinical picture and the course of the disease with its recurrences and histopathology. Flame figures in histologic sections are an important diagnostic feature but not diagnostic per se for the disease because they represent a reaction pattern that can occur in other conditions. A dilution of Wells' syndrome by making flame figures the central criterion of diagnosis and by lumping all flame figure-positive skin reactions together is therefore unjustified.

Cytoskeleton-associated plectin: in situ localization, in vitro reconstitution, and binding to immobilized intermediate filament proteins.

Abstract: The association and interaction of plectin (Mr 300,000) with intermediate filaments and filament subunit proteins were studied. Immunoelectron microscopy of whole mount cytoskeletons from various cultured cell lines (rat glioma C6, mouse BALB/c 3T3, and Chinese hamster ovary) and quick-frozen, deep-etched replicas of Triton X-100-extracted rat embryo fibroblast cells revealed that plectin was primarily located at junction sites and branching points of intermediate filaments. These results were corroborated by in vitro recombination studies using vimentin and plectin purified from C6 cells. Filaments assembled from mixtures of both proteins were extensively crosslinked by oligomeric plectin structures, as demonstrated by electron microscopy of negatively stained and rotary-shadowed specimens as well as by immunoelectron microscopy; the binding of plectin structures on the surface of filaments and cross-link formation occurred without apparent periodicity. Plectin's cross-linking of reconstituted filaments was also shown by ultracentrifugation experiments. As revealed by the rotary-shadowing technique, filament-bound plectin structures were oligomeric and predominantly consisted of a central globular core region of 30-50 nm with extending filaments or filamentous loops. Solid-phase binding to proteolytically degraded vimentin fragments suggested that plectin interacts with the helical rod domain of vimentin, a highly conserved structural element of all intermediate filament proteins. Accordingly, plectin was found to bind to the glial fibrillar acidic protein, the three neurofilament polypeptides, and skin keratins. These results suggest that plectin is a cross-linker of vimentin filaments and possibly also of other intermediate filament types.

Absence of clonal beta and gamma T-cell receptor gene rearrangements in a subset of peripheral T-cell lymphomas.

Abstract: The authors describe a set of seven peripheral T-cell lymphomas that lack detectable rearrangements of T-cell receptor (TCR) genes. All cases showed antigenic profiles consistent with T-cell lymphoma, including expression of Leu-5 (CD2) antigen. However, few other T-lineage markers were found, and none of the cases tested (6 of 7) bound antibody recognizing the constant region of the beta TCR protein. Each case showed exclusively germline configurations of DNA for the beta TCR genes in Southern blot analyses with the use of several different combinations of restriction enzymes and DNA hybridization probes. One case contained clonal rearrangements of the gamma TCR gene and of the immunoglobulin heavy chain gene. Our results suggest that certain cases of peripheral T-cell lymphoma may lack rearrangements of TCR genes--particularly those cases expressing restricted numbers of T-lineage antigens. In view of these findings, failure to detect rearrangements of TCR genes by Southern blot analyses is not necessarily inconsistent with malignant lymphocytic proliferations in T-lineage neoplasia.

The Ecology of Amorphous Aggregations (Marine Snow) in the Northern Adriatic Sea

Abstract: . In the water-column of the Gulf of Trieste (Northern Adriatic Sea) flocculent, amorphous aggregates known as marine snow reach maximum density and dimensions up to 20cm in diameter during summer months. Sampling of these fragile macro-aggregates was carried out by SCUBA-divers. A large detrital component was found to be embedded in an organic matrix together with a large array of intact phytoplankton species. Heterotrophic bacterial density ranged from 2–65 × 108 cells-g-1 (marine snow dry wt) and is therefore of the same order of magnitude as in the surface layer of the sediments of the Gulf. In terms of biomass, bacteria reached only 30–95% of heterotrophic microflagellates. A mean abundance of marine snow of 5g (marine snow dry wt) m-3 was obtained for the water-column above the pyenolinc. At this boundary layer, however, a mean abundance of about 10g (marine snow dry wt) m-3 led to the formation of a distinct, 10-50cm thick layer. Based on these data and sedimentation rates of marine snow to the pyenoclinc (38 g [marine snow dry wt] m-2 d-1) the potential ecological significance of these macro-aggregates for the pelagic system of the Gulf of Trieste is discussed.

Lyapunov instability of dense Lennard-Jones fluids

Abstract: We present calculations of the full spectra of Lyapunov exponents for 8- and 32-particle systems in three dimensions with periodic boundary conditions and interacting with the repulsive part of a Lennard-Jones potential. A new algorithm is discussed which incorporates ideas from control theory and constrained nonequilibrium molecular dynamics. Equilibrium and nonequilibrium steady states are examined. The latter are generated by the application of an external field F/sub e/ through which equal numbers of particles are accelerated in opposite directions, and by thermostatting the system using Nose-Hoover or Gauss mechanics. In equilibrium (F/sub e/ = 0) the Lyapunov spectra are symmetrical and may be understood in terms of a simple Debye model for vibrational modes in solids. For nonequilibrium steady states (F/sub e/not =0) the Lyapunov spectra are not symmetrical and indicate a collapse of the phase-space density onto an attracting fractal subspace with an associated loss in dimensionality proportional to the square of the applied field. Because of this attractor's vanishing volume in phase space and the instability of the corresponding repellor it is not possible to observe trajectories violating the second law of thermodynamics in spite of the time-reversal invariance of the equations of motion. Thus Nose-Hoover mechanics, ofmore » which Gauss's isokinetic mechanics is a special case, resolves the reversibility paradox first stated by J. Loschmidt (Sitzungsber. kais. Akad. Wiss. Wien 2. Abt. 73, 128 (1876)) for nonequilibrium steady-state systems.« less

Circadian fluctuations of plasminogen activator inhibitor and tissue plasminogen activator levels in plasma of patients with unstable coronary artery disease and acute myocardial infarction.

Abstract: A decrease in the fibrinolytic potential, mainly due to an elevation of plasminogen activator inhibitor (PAI), has been described in patients with stable coronary artery disease and a previous myocardial infarction. We investigated plasma levels of PAI and tissue plasminogen activator (t-PA) and their possible circadian variations in patients with unstable coronary artery disease (CAD). Sixty-three patients were studied for at least 2 consecutive days during their stay at the coronary care unit (CCU). Diurnal plasma fluctuations in PAI and t-PA and onset of further myocardial ischemic episodes were monitored. As controls we used 22 age-matched patients submitted to the clinic because of non cardiac chest pain or valvular disease who revealed no evidence of CAD. PAI levels were significantly elevated in patients with unstable CAD (p less than 0.0001) but were not influenced by the extent of underlying CAD, history of previous myocardial infarction, known risk factors for CAD, or by extent of myocardial damage. The circadian variation of PAI levels with peak values between midnight and 6 A.M. found in controls was still present in patients but at a higher level. Preservation of circadian pattern in PAI plasma levels despite myocardial ischemic attacks indicates that elevation of PAI is rather not caused by a reactive phenomenon. On the other hand, elevated PAI levels and episodes of severe myocardial ischemia exhibiting a median time of onset at 10 A.M. seem to be closely related.

The chemistry of detrital chromian spinels and its implications for the geodynamic evolution of the Eastern Alps

Abstract: Detrital chromian spinel is a key mineral in paleogeographic reconstructions. The chemical compositions of the spinels provide even more specific information about their host ophiolites because their chemistry is related to the degree of melting of the mantle peridotite and thus to the geotectonic environment of ocean crust formation.

Serum osteocalcin levels in diabetes mellitus: analysis of the type of diabetes and microvascular complications.

Abstract: Recent studies indicate that serum levels of osteocalcin, a 49-aminoacid bone matrix protein, are a biochemical marker of bone formation. In order to study bone metabolism in diabetes mellitus, in 28 patients with Type 1 (insulin-dependent) diabetes mellitus, in 38 patients with Type 2 (non-insulin-dependent) diabetes mellitus and two control groups, matched for Type 1 and Type 2 diabetic patients, respectively, serum levels of osteocalcin, parathyroid hormone and 25 hydroxy vitamin D were measured by radioimmunoassay. Whereas in Type 1 diabetic patients and control subjects serum levels of osteocalcin and 25 hydroxy vitamin D were not statistically different, serum osteocalcin and 25 hydroxy vitamin D levels were significantly decreased in Type 2 diabetic patients when compared with corresponding control subjects (p<0.03 and p<0.001, respectively). Independent of the type of diabetes, serum parathyroid hormone levels were comparable in diabetic patients and matched control subjects. Serum osteocalcin levels were significantly lower in Type 1 diabetic patients with retinopathy and/or proteinuria than in Type 1 diabetic patients without microangiopathy (p<0.05). Whereas serum parathyroid hormone levels in Type 2 diabetic patients with retinopathy and/or proteinuria were significantly increased (p<0.02), 25 hydroxy vitamin D levels were decreased (p<0.02) when compared with Type 2 diabetic patients without microangiopathy. Our data give evidence of a vitamin D deficiency and a decreased bone formation in patients with Type 2 diabetes mellitus. In Type 1 diabetes mellitus bone formation as reflected by serum osteocalcin levels is influenced by the presence or absence of microangiopathic complications.

Nitrate, nitrate reduction and organic nitrogen in plants from different ecological and taxonomic groups of Central Europe

Abstract: 48 plant species of the families Asteraceae, Chenopodiaceae, Ericaceae, Fabaceae, Lamiaceae, Polygonaceae and Urticaceae were investigated in 14 natural habitats of Central Europe having different nitrate supplies, with respect to their nitrate content, nitrate reductase activity (NRA) and organic nitrogen content. Plants that were flowering were selected where possible for analysis. The plants were subdivided into flowers, laminae, petioles+shoot axes and below-ground organs. Each organ was analyzed separately. Differences among species were found for the three variables investigated. Apart from the Fabaceae, which had particularly high concentrations of organic N, these differences reflect mainly the ecological behaviour, i.e. high nitrate and organic N contents and NRA values per g dry weight were found in species on sites rich in nitrate, and vice versa. Nitrate content, NRA and organic N content were correlated with “nitrogen figures” of Central European vascular plants defined by Ellenberg (1979). By use of regression equations this correlation was tested with species from other systematic groups. Some species were attributed with calculated “N figures” for the first time.

Negative cortical DC shifts preceding and accompanying simultaneous and sequential finger movements.

Abstract: Cortical DC shifts preceding and accompanying the execution of five different bimanual motor tasks were analysed in 20 subjects. All tasks required repetitive flexions and extensions of the two forefingers for a period of at least six seconds. The temporal and spatial structures organization varied in the different tasks: (1) Simultaneous agonistic performance (forefinger flexion on both sides), (2) simultaneous antagonistic performance (e.g. flexion of the right, extension of the left forefinger), (3) sequential agonistic performance, (4) sequential antagonistic performance, (5) uncoordinated flexions and extensions of the two forefingers. Compared to (1) and (2), conditions (3) and (4) included a temporal delay between the performance of the two forefingers; compared to (1) and (3), conditions (2) and (4) required the subjects to perform movements of opposite directions with their two forefingers. Effects of the temporal factor (T; simultaneous vs. sequential) and the spatial factor (S; agonistic vs. antagonistic) on cortical DC shifts were investigated. The voluntary initiation of each motor task was preceded by a Bereitschaftspotential (BP). The performance of the complex tasks (1-4) was accompanied by a slow negative DC potential shift (N-P). In general, the BP did not differ depending on the temporal or spatial structures of the tasks (1-4). However, amplitudes of N-P (i.e. during tasks) were influenced by the temporal factor with significantly larger amplitudes in sequential than in simultaneous tasks. This difference was not a global phenomenon in all recordings but was selectively found in the recordings over the fronto-central midline.(ABSTRACT TRUNCATED AT 250 WORDS)