Showing papers by "University of Graz published in 1991"
TL;DR: This review provides a comprehensive summary on the chemical properties of 4-hydroxyalkenals and malonaldehyde, the mechanisms of their formation and their occurrence in biological systems and methods for their determination, as well as the many types of biological activities described so far.
6,456 citations
TL;DR: The Voronoi diagram as discussed by the authors divides the plane according to the nearest-neighbor points in the plane, and then divides the vertices of the plane into vertices, where vertices correspond to vertices in a plane.
Abstract: Computational geometry is concerned with the design and analysis of algorithms for geometrical problems. In addition, other more practically oriented, areas of computer science— such as computer graphics, computer-aided design, robotics, pattern recognition, and operations research—give rise to problems that inherently are geometrical. This is one reason computational geometry has attracted enormous research interest in the past decade and is a well-established area today. (For standard sources, we refer to the survey article by Lee and Preparata [19841 and to the textbooks by Preparata and Shames [1985] and Edelsbrunner [1987bl.) Readers familiar with the literature of computational geometry will have noticed, especially in the last few years, an increasing interest in a geometrical construct called the Voronoi diagram. This trend can also be observed in combinatorial geometry and in a considerable number of articles in natural science journals that address the Voronoi diagram under different names specific to the respective area. Given some number of points in the plane, their Voronoi diagram divides the plane according to the nearest-neighbor
4,236 citations
Journal Article•
1,812 citations
TL;DR: Alpha-tocopherol is an important, yet not the only parameter that determines the oxidation resistance of LDL, and by supplementating plasma with vitamin E, the alpha-tocaperol content of LDL could be increased from approximately 9 to 30 mol/mol LDL and also the oxidative resistance increased nearly linearly with increasing alpha-ocopherol content.
620 citations
TL;DR: It is shown that in humans the oxidation resistance of LDL can be increased by vitamin E supplementation and the association was seen between levels of carotenoids and vitamin E in plasma and LDL.
478 citations
Journal Article•
TL;DR: In this article, the MR images of six patients, 52-63 years old, who exhibited incidental punctate white matter hyperintensities on MR images before death were used to unravel the morphologic correlate of such lesions.
Abstract: Postmortem examinations were made of the brains of six patients, 52-63 years old, who exhibited incidental punctate white matter hyperintensities on MR images before death. Our aim was to unravel the morphologic correlate of such lesions. By repeating the MR study after fixation on four specimens, cutting the brain parallel to the MR imaging plane, and examining whole-hemisphere microscopic sections, we optimized lesion identification. The white matter signal abnormalities were better delineated on pre- than postmortem scans, and visual inspection of the brain slices was normal in all but one location. Histologically, we found areas of reduced myelination with atrophy of the neuropil around fibrohyalinotic arteries as well as different stages of perivenous damage. The latter ranged from spongiform transformation of the neuropil and scattered foci of demyelination to large perivenous areas with marked rarefaction of myelinated fibers. Edematous glial swelling in foci of ganglion cell heterotopia caused subcortical white matter hyperintensities in one case. Our results suggest minor perivascular damage but not infarction as the most likely substrate of punctate MR white matter hyperintensities in elderly brains. Histologic correlations with MR images obtained during life or with studies of unfixed material are necessary to analyze such small lesions.
292 citations
TL;DR: The investigation shows complex flow patterns especially in the carotid sinus where flow separation occurs at the outer wall throughout the systolic deceleration phase and the changing sign of the velocity near the outer sinus wall results in oscillating shear stress during the pulse cycle.
Abstract: Numerical analysis of flow phenomena and wall shear stresses in the human carotid artery bifurcation has been carried out using a three-dimensional geometrical model. The primary aim of this study is the detailed discussion of non-Newtonian flow velocity and wall shear stress during the pulse cycle. A comparison of non-Newtonian and Newtonian results is also presented. The applied non-Newtonian behavior of blood is based on measured dynamic viscosity. In the foreground of discussion are the flow characteristics in the carotid sinus. The investigation shows complex flow patterns especially in the carotid sinus where flow separation occurs at the outer wall throughout the systolic deceleration phase. The changing sign of the velocity near the outer sinus wall results in oscillating shear stress during the pulse cycle. At the outer wall of the sinus at maximum diameter level the shear stress ranges from -1.92 N/m2 to 1.22 N/m2 with a time-averaged value of 0.04 N/m2. At the inner wall of the sinus at maximum diameter level the shear stress range is from 1.16 N/m2 to 4.18 N/m2 with a mean of 1.97 N/m2. The comparison of non-Newtonian and Newtonian results indicates unchanged flow phenomena and rather minor differences in the basic flow characteristics.
288 citations
TL;DR: The efficiency of vitamin E-dependent (= k) and the vitamin independent (= a) oxidation resistance seem to be subject specific with strong individual variation.
Abstract: Human low density lipoprotein (LDL) with a molecular mass of 2.5 million contains on average 1300 molecules of polyunsaturated fatty acids (PUFAs) bound in the different lipid classes. The predominant antioxidant in LDL is a-tocopherol, with an average of 6 molecules in each LDL particle. The other substances with potential antioxidant activity are: gamma-tocopherol, β-carotene, a-carotene, lycopene, cryptoxanthin, cantaxanthin, phytofluene and ubiquinol-10. Each is present in amounts of only 1/ 20th to 1/300th of that of a-tocopherol. If LDL is exposed to oxidative conditions (Cuions, macrophages) a lag phase precedes the oxidation of PUFAs. During the lag phase the antioxidants disappear with a-tocopherol the first to go and β-carotene the last.The lag phase, which can readily be determined, is an index of the oxidation resistance of LDL. If LDL is loaded with vitamin E in vitro its oxidation resistance increases linearly with its a-tocopherol content according to the equation, y=kx+a. The same relation...
263 citations
Book•
23 May 1991260 citations
TL;DR: The size of the largest nodal metastasis was not related to the clinical stage or survival, but did correlate with the number of positive nodes, and greater numbers ofpositive nodes were found in stage III than stage IV.
239 citations
TL;DR: T. reesei mutants developed after 1978 show approximately the same capacity to produce cellulase, but the different cellulases show very different capacities for hydrolyzing cellulose.
TL;DR: Numerical results are presented for axial and secondary flow velocity and wall shear stresses with special emphasis on the fluid dynamics in the carotid sinus, of major interest because it is affected preferentially by lesions.
TL;DR: The results show that the complex flow in the sinus is affected by the angle variation, and the haemodynamic phenomena, which are important in atherogenesis, are more pronounced in the large angle bifurcation.
TL;DR: Three new bradykinin (BK) antagonists were tested against the effects of BK in 9 bioassay preparations including visceral smooth muscles, vasoconstriction, plasma protein extravasation, release of prostaglandin E2, bronchoconStriction, and stimulation of afferent C‐fibre nociceptors.
Abstract: 1. Three new bradykinin (BK) antagonists, D-Arg0-Hyp3-Thi5-D-Tic7-Oic8-BK (compound I), D-Arg0-Hyp3-D-Tic7-Oic8-BK (compound II), and Arg(Tos)1-Hyp3-Thi5-D-Tic7-Oic8-BK (compound III), were tested against the effects of BK in 9 bioassay preparations including visceral smooth muscles, vasoconstriction, plasma protein extravasation, release of prostaglandin E2, bronchoconstriction, and stimulation of afferent C-fibre nociceptors. In some of these tests the effects of the new compounds were compared with those of the antagonist D-Arg0-Hyp2-Thi5,8-D-Phe7-BK (compound IV), described by Stewart & Vavrek (1987). 2. For all bioassays the general rank order of potency of the compounds was found to be I greater than II greater than III much greater than IV. The new antagonists were long-acting; in some bioassays their effects outlasted the duration of the experiment. 3. The inhibitory effects of the new BK antagonists were specific for BK; actions of noradrenaline, angiotensin II, acetylcholine or histamine were unaffected by the antagonists. They did not stimulate the release of histamine or prostaglandins. An agonistic effect was observed only with very high concentrations of compounds I and II in the plasma protein extravasation test. 4. The long duration of action of the new BK antagonists is probably due to a high and long-lasting affinity to the BK receptors. A high resistance of the antagonists to enzymatic destruction may be another reason. 5. The new BK antagonists will be valuable tools for the investigation of the pathophysiological role of BK. In addition they may offer a potential for therapeutic applications.
01 Jul 1991
TL;DR: The theory of the two-way technique using geostationary communication satellites is presented showing the high accuracy potential of the method and the advantages of the use of spread spectrum techniques are outlined.
Abstract: The history of two-way satellite time transfer is provided and developments in satellite communications technology conducive to this time transfer technique are briefly reviewed. The difference between one-way and two-way satellite time transfer is explained, and the advantages and disadvantages of the two-way method are pointed out. The theory of the two-way technique using geostationary communication satellites is presented showing the high accuracy potential of the method. The advantages of the use of spread spectrum techniques are outlined. The implementation of the two-way method using communication satellites and small Earth stations using pseudonoise (PN) modems is described. Methods for signal delay calibration are dealt with. Existing links are listed and their performances are given. The future use of the two-way technique using communication satellites is discussed. >
TL;DR: The results confirm the presence of subtle neuropsychologic deficits and indicate a higher frequency of white matter signal abnormalities in essential hypertension, as shown on magnetic resonance imaging, but do not indicate a correlation of these findings with each other.
Abstract: To search for a morphologic basis of cognitive impairment possibly associated with essential hypertension, we studied 35 otherwise asymptomatic hypertensive individuals (mean age, 38.7 years; range, 22 to 49 years) and 20 normotensive control subjects (mean age, 37.9 years; range, 26 to 49 years) using neuropsychologic tests and magnetic resonance imaging. Irrespective of drug treatment, hypertensive individuals performed significantly worse than did control subjects when assessed for verbal memory and total learning and memory capacity, while there were no differences in test results of visual memory, attention, vigilance, and reaction time. The hypertensive individuals also described themselves as less active but ranked similar on five other mood subscales. Punctate high-signal intensities of the white matter were found almost twice as often in the hypertensive group (38%) as in the control group (20%). There was no difference in test performance between hypertensive individuals with and those without white matter lesions, however. Our results confirm the presence of subtle neuropsychologic deficits and indicate a higher frequency of white matter signal abnormalities in essential hypertension, as shown on magnetic resonance imaging, but do not indicate a correlation of these findings with each other.
TL;DR: The pharmacology of ruthenium red as a capsaicin antagonist is reviewed, attempting to define the usefulness and the limits of this substance as a tool in sensory neuron research.
TL;DR: It is shown that LDL and Lp(a) are very similar with respect to their fatty acid and antioxidant composition and Cu2(+)-mediated oxidation of Lp (a) is retarded in comparison to LDL which might be due to the higher content of NANA in L p(a).
TL;DR: Data indicate that neopterin plasma levels might be a valuable parameter in activity staging and therapeutic follow up of atherosclerotic patients and an involvement of the nonspecific immune system in atherogenesis is suggested by the increased plasma neopterIn concentrations.
TL;DR: Individual cases were associated with congenital lymphoedema, Klippel‐Trenaunay syndrome and early‐onset varicose veins, and showed a predilection for the extremities.
Abstract: Spindle cell haemangioendothelioma is an uncommon vascular lesion, of which 35 cases have been previously reported. A further 20 cases are reported herein. These lesions affected a wide age range in both sexes, and showed a predilection for the extremities. Twelve patients had multiple lesions and, in these cases, local progression over many years but no true recurrence was typical. None of the 20 patients developed metastases, but one later developed an angiosarcoma. Individual cases were associated with congenital lymphoedema. Klippel-Trenaunay syndrome and early-onset varicose veins. Histologically, in addition to the admixture of cavernous spaces and solid spindle cell/epithelioid cell areas, the presence both of irregularly distributed and perivascular smooth muscle cells and of malformed variably-sized vessels at the periphery of almost every lesion was noted in each case. Reticulin staining, immunohistochemistry and electronmicroscopy revealed the presence of primitive vessel formation and partial endothelial differentiation in the solid spindle cell areas. Combining these data with those from previously published series, it is suggested that spindle cell haemangioendothelioma is a non-neoplastic lesion (rather than a borderline malignancy as it is currently regarded) and that its development correlates with histological and/or clinical evidence of a malformed vasculature at the affected site.
TL;DR: Although apoE and LPL are both expressed in adipocytes in a differentiation-dependent manner, the time course of their expression differs as do their responses to cellular lipid content and tumor necrosis factor, and it is concluded that these genes are not coordinately regulated in adip cells.
TL;DR: An optimized regularization technique is developed that can be used for the inversion of such light-scattering data and has been successfully tested for a large number of simulated and measured data.
Abstract: Optical particle sizing in the range of 10 nm up to several micrometers by means of quasi-elastic and elastic light scattering requires sophisticated data inversion techniques. We have developed an optimized regularization technique that can be used for the inversion of such light-scattering data. The technique has been successfully tested for a large number of simulated and measured data. It is easy to handle. Typical problems that arise in practical applications are discussed.
TL;DR: It was concluded that the recombinant plasmid in the transformant carried an allelic form of the ERG1 gene, which proved to be resistant to the Al derivative, terbinafine.
TL;DR: None of the 38 patients reclassified as having a Stage IB lesion, including 16 who were treated conservatively, developed a recurrence, and the FIGO classification is not a guideline for treatment.
Abstract: In 1985 the International Federation of Gynecology and Obstetrics (FIGO) subdivided Stage IA cervical cancer and specified metric criteria to demarcate Stage IA from Stage IB. Early stromal invasion (Stage IA1) denotes the first invasive protrusions of a carcinoma in situ into the stroma. Microcarcinomas (Stage IA2) are small cancers a number of orders of magnitude larger than Stage IA1 lesions and with a maximum depth of invasion of 5 mm and a maximum horizontal spread of 7 mm; larger lesions are classified as Stage IB. This study reviews 486 patients previously classified as having Stage IA disease. This yielded 344 Stage IA1 and 101 Stage IA2 lesions; 41 cancers were reclassified as Stage IB. Three hundred nine, 89, and 38 patients were followed for greater than or equal to 5 years. One (0.3%) patient with Stage IA1 disease re-presented with Stage IIB disease 12 years after conization. Five (5.6%) patients with Stage IA2 lesions developed invasive recurrences; three died. None of the 38 patients reclassified as having a Stage IB lesion, including 16 who were treated conservatively, developed a recurrence. The FIGO classification is not a guideline for treatment. Stage IA1 lesions can be treated conservatively, but treatment in Stage IA2 must be individualized. Risk factors such as vascular space involvement and confluency are of high sensitivity but low specificity.
TL;DR: In this paper, the synthesis and spectral properties of three new and highly fluorescent solvent polarity probes are described, and the origin of the unusual solvatochromic properties is discussed in terms of the resonance structures of this new group of molecular probes.
TL;DR: Semiquantitative volumetric measurements yielded a significantly increased ventricular-to-intracranial cavity ratio and the cortical atrophy ratings correlated positively with disease duration and cognitive test performance was significantly worse in patients than in controls and was most impaired in those patients with morphologic cerebral abnormalities.
Abstract: We compared brain magnetic resonance imaging and neuropsychologic performance in 20 neurologically asymptomatic patients suffering from idiopathic dilated cardiomyopathy (mean age 41 [range 18-49] years) and 20 age-matched controls (mean age 38 [range 28-49] years). Patients exhibited a significantly higher rate of cerebral infarcts (20% versus 0%, p less than 0.05) and cortical (50% versus 5%, p less than 0.01) and ventricular (55% versus 15%, p less than 0.02) atrophy than controls. Accordingly, semiquantitative volumetric measurements yielded a significantly increased ventricular-to-intracranial cavity ratio in the patients (6.2 +/- 2.9% versus 4.1 +/- 1.3%, p less than 0.01). This ratio and the cortical atrophy ratings correlated positively with disease duration (r = 0.63 and 0.54, p less than 0.05). Cognitive test performance was significantly worse in patients than in controls and was most impaired in those patients with morphologic cerebral abnormalities.
TL;DR: Reliable histological subclassification proved impossible since almost all lesions were of mixed type, albeit often with a single predominant vessel type—of which venous was the most common.
Abstract: We have studied 74 benign intramuscular angiomas in order to try and correlate clinical behaviour with histological appearances. The purpose was to find means of predicting those which would recur. Mean age at presentation was 17.6 years and 85% of the cases presented before age 30. The male: female ratio was 1.4:1. Anatomical distribution was 32% lower limb, 27% head/neck, 24% upper limb and 17% trunk. Reliable histological subclassification proved impossible since almost all lesions were of mixed type, albeit often with a single predominant vessel type--of which venous (42%) was the most common. Over 90% of the lesions contained a variably prominent adipocytic component. More than 50% of patients suffered local recurrence. Neither predominant vessel type nor anatomical localization correlated with recurrence, which was always due to incomplete excision.
TL;DR: The structure of a derivative of coenzyme F430 from methanogenic bacteria, the bromide salt of 12,13-diepi-F430 pentamethyl ester (5, X = Br), was determined by X-ray structure analysis as discussed by the authors.
Abstract: The structure of a derivative of coenzyme F430 from methanogenic bacteria, the bromide salt of 12,13-diepi-F430 pentamethyl ester (5, X = Br), was determined by X-ray structure analysis. It reveals a more pronounced saddle-shaped out-of-plane deformation of the macrocycle than any hydroporphinoid Ni complex investigated so far. The crystal structure confirms the constitution proposed for coenzyme F430 (2) and shows that in the epimer 5, the three stereogenic centers in ring D, C(17), C(18), and C(19), have the (17S)-, (18S)-, and (19R)-configuration, respectively. Deuteration and 2D-NMR studies independently demonstrate that native coenzyme F430 (2) has the same configuration in ring D as the epimer 5. Therefore, our original tentative assignment of configuration at C(19) and C(18) [1] has to be reversed. This completes the assignment of configuration for all stereogenic centers in coenzyme F430, which has the structure shown in Formula2.
TL;DR: In small colonies containing 400–800 bees, nearly one-quarter of the radioactivity which could not be recovered in the nurses was fed by them in a protein-bound form to other members of the worker caste.
Abstract: Honeybee nurses (8 days old) were injected with 14C-phenylalanine. These bees then dispensed the 14C-labelled protein-rich products of their hypopharyngeal glands to the queen and the brood, and also to young drones and workers of all age classes. In small colonies containing 400–800 bees, nearly one-quarter of the radioactivity which could not be recovered in the nurses was fed by them in a protein-bound form to other members of the worker caste. During one night, one nurse fed an average of 4–5 foragers with proteinaceous food. The role of nurses in the work allotment system of honeybee colonies therefore needs a new, extended definition. Nurses are largely responsible for preparing nutrients from pollen, which is difficult to digest. They then distribute the nutritionally valuable protein produced by their hypopharyngeal glands to practically all hive mates.
TL;DR: The exceptional selectivity with which capsaicin acts on a population of peptide-containing thin primary afferent neurons has made this drug an important tool with which to investigate the neuroanatomical, neurochemical and functional implications of these neurons.
Abstract: It was only by the middle of this century that the extent of the sensory innervation of visceral organs including the gastrointestinal tract was revealed. Quantitative analysis showed that as much as 90% of the fibers in the vagus nerve are of afferent nature and that also in the splanchnic and pelvic nerves the afferent-to-efferent fiber ratio is 3: 1 and 1: 1, respectively (see Leek, 1977). These sensory neurons are primary afferent neurons, the vagal afferents having their cell bodies in the nodose ganglion and the splanchnic and pelvic afferents arising from the dorsal root (spinal) ganglia. The sensory nervous system is thought of as a receptive and afferent system that re-flexly activates efferent pathways and thereby enables the organism to react to changes in the external and internal environment and to maintain homeostasis. In addition, there is evidence that a population of peptide-containing afferent neurons can act as an effector system by itself (see Szolcsanyi, 1984b; Holzer, 1988; Maggi and Meli 1988).