Showing papers by "Jagiellonian University published in 1994"

Role of angiogenesis in patients with cerebral ischemic stroke.

Abstract: Stroke is one of the most common causes of mortality and morbidity in the Western world. It results from the occlusion of a cerebral artery followed by severe disturbances in blood supply through microvessels to brain tissue. Despite an extensive literature its pathophysiology is poorly understood, and this has severely impeded the logical development of therapy.Brains were obtained from 10 patients aged 46 to 85 years with survival times of 5 to 92 days after their stroke. Infarcted areas and representative control tissues from the contralateral uninvolved brain hemisphere were collected. Microvessel density was measured microscopically. A total of 6520 microvessels were scored in 10,801 areas. The level of activation of the endothelial cells was studied by immunohistochemistry using three monoclonal antibodies, viz, E-9, raised against activated endothelial cells; IG11, recognizing vascular cell adhesion molecule-1; and anti-proliferating cell nuclear antigen. Angiogenic activity in tissue extracts was ...

Hydrophobic barriers of lipid bilayer membranes formed by reduction of water penetration by alkyl chain unsaturation and cholesterol.

Abstract: The hydrophobicity profiles across phosphatidylcholine (PC)-cholesterol bilayer membranes were estimated in both frozen liposome suspensions and fluid-phase membranes as a function of alkyl chain length, unsaturation, and cholesterol mole fraction. A series of stearic acid spin labels, with the probe attached to various positions along the alkyl chain, cholesterol-type spin labels (cholestane and androstane spin labels), and Tempo-PC were used to examine depth-dependent changes in local hydrophobicity, which is determined by the extent of water penetration into the membrane. Local hydrophobicity was monitored primarily by observing the z component of the hyperfine interaction tensor (A,) of the nitroxide spin probe in a frozen suspension of the membrane at -150 "C and was further confirmed in the fluid phase by observing the rate of collision of Fe(CN)63- with the spin probe in the membrane using saturation recovery ESR. Saturated-PC membranes show low hydrophobicity (high polarity) across the membrane, comparable to 2-propanol and 1-octanol, even at the membrane center where hydrophobicity is highest. Longer alkyl chains only make the central hydrophobic regions wider without increasing the level of hydrophobicity. Introduction of a double bond at C9-C10 decreases the level of water penetration at all locations in the membrane, and this effect is considerably greater than the cis configuration than with the trans configuration. Incorporation of cholesterol (30 mol %) dramatically changes the profiles; it decreases hydrophobicity (increases water penetration) from the polar headgroup region to a depth of approximately C7 and C9 for saturated- and unsaturated-PC membranes, respectively, which is about where the bulky rigid steroid ring structure of cholesterol reaches in the membrane. Membrane hydrophobicity sharply increases at these positions from the level of methanol to the level of pure hexane, and hydrophobicity is constant in the inner region of the membrane. Thus, formation of effective hydrophobic barriers to permeation of small polar molecules requires alkyl chain unsaturation and/or cholesterol. The thickness of this rectangular hydrophobic barrier is less than 50% of the thickness of the hydrocarbon regions. Results obtained in dioleoyl-PC- cholesterol membranes in the fluid phase are similar to those obtained in frozen membranes. These results correlate well with permeability data for water and amino acids in the literature.

Modified valence indices from the two-particle density matrix

Abstract: The modified ionic and covalent valence indices are introduced, defined in the framework of the two-particle density matrix, with respect to the reference state of separated atoms or ions (SAL). They include only quadratic contributions in changes of the molecular charge-and-bond order matrix elements, relative to the SAL. General properties of the modified valence indices are examined and illustrative qualitative results for model systems are presented. Numerical UHF SCF MO valence data for selected diatomic and triatomic molecules are reported and interpreted in terms of the valence saturation effect and the ionic vs. covalent valence competition. A three-orbital valence model of a symmetric transition state of the bond-forming–bond-breaking reaction supports the BEBO model postulate of preservation of the total “bond order.” The model predictions are compared with the UHF numerical values. © 1994 John Wiley & Sons, Inc.

Pathogenesis of periodontitis: a major arginine-specific cysteine proteinase from Porphyromonas gingivalis induces vascular permeability enhancement through activation of the kallikrein/kinin pathway.

Abstract: To elucidate the mechanism of production of an inflammatory exudate, gingival crevicular fluid (GCF), from periodontal pockets in periodontitis, we examined the vascular permeability enhancement (VPE) activity induced by an arginine-specific cysteine proteinase, Arg-gingipain-1 (RGP-1), produced by a major periopathogenic bacterium, Porphyromonas gingivalis. Intradermal injections into guinea pigs of RGP-1 (> 10(-8) M), or human plasma incubated with RGP-1 (> 10(-9) M), induced VPE in a dose- and activity-dependent manner but with different time courses for the two routes of production. VPE activity induced by RGP-1 was augmented by kininase inhibitors, inhibited by a kallikrein inhibitor and unaffected by an antihistamine drug. The VPE activity in human plasma incubated with RGP-1 also correlated closely with generation of bradykinin (BK). RGP-1 induced 30-40% less VPE activity in Hageman factor-deficient plasma and no VPE in plasma deficient in either prekallikrein (PK) or high molecular weight kininogen (HMWK). After incubation with RGP-1, plasma deficient in PK or HMWK, reconstituted with each missing protein, caused VPE, as did a mixture of purified PK and HMWK, but RGP-1 induced no VPE from HMWK. The VPE of extracts of clinically isolated P. gingivalis were reduced to about 10% by anti-RGP-1-IgG, leupeptin, or tosyl-L-lysine chloromethyl ketone, which paralleled effects observed with RGP-1. These results indicate that RGP-1 is the major VPE factor of P. gingivalis, inducing this activity through PK activation and subsequent BK release, resulting in GCF production at sites of periodontitis caused by infection with this organism.

Measurement of total and partial photon proton cross sections at 180 GeV center of mass energy

Abstract: Photon proton cross sections for elastic light vector meson production, σelνp, inelastic diffractive production, σndνp, non-diffractive production, σdνp, as well as the total cross section, σtotνp, have been measured at an average υp center of mass energy of 180 GeV with the ZEUS detector at HERA. The resulting values are σelνp = 18 ± 7 μb, σdνp = 33 ± 8 μb, σndνp = 91 ± 11 μb, and σtotνp 143 ± 17 μb, where the errors include statistical and systematic errors added in quadrature.

Quantum mechanical valence study of a bond-breaking-bond-forming process in triatomic systems

Abstract: The recently introduced set of the quadratic, two-electron covalent and ionic valence indices is used to investigate the bond-breaking–bond-forming (BB-BF) process in an atom exchange reaction between H2 and X (X = H, F—I) as well as in the O2—H system Valence changes accompanying selected charge reorganizations are examined within the three-orbital model and valence diagrams for symmetric transition states (TSs) are given The UHF valence data for Li2O and CO2 and the H—H—X, O—O—H, and O—H—O (ABC) TSs (collinear and angular) are reported and compared to valence data in the separated fragments limits (SFL), AB and BC The overall valence, ν(ABC), and the total (ionic plus covalent) diatomic valences, νAB and νBC, are used as measures of the overall bond-order in a concerted BB–BF reaction, to test the postulate of the bond-energy–bond-order (BEBO) model In collinear TSs of H2X, ν ≊ −1, ie, one bonding electron pari, is found to be roughly preserved, whereas in the angular H2X and in collinear O—H—O TSs, the effect of increased valence at the saddle-point is observed, relative to that of diatomic fragments (reactiants or products) For the angular O—O—H TS, a similar increase in | ν (ABC)| relative to both O2 and OH SFLs is detected; smaller changes relative to the O2 data are found in the collinear TS This observation is in agreement with earlier predictions from the intersecting-state model The relative diatomic valences, ν/ν and ν/ν, are shown to conserve the overall relative bond multiplicity around 1 in both collinear and angular TSs of the H2—X systems © 1994 John Wiley & Sons, Inc

Differential effects of zooplankton species on ciliate community structure

Abstract: An in situ bioassay experiment using Diacyclops bicuspidatus thomasi, Daphnia rosea, Diaptomus novamexicanus, and Holopedium gibberum single-species treatments was conducted to assess the influence of these zooplankters on the ciliate community structure of Castle Lake, California. At peak ambient abundances for adult individuals, these zooplankters all strongly depressed ciliate population growth rates. The ranking of the zooplankton-imposed ciliate death rates, from least to most severe, was Holopedium C-C Daphnia = Diaptomus

Humoral immunosuppression in men exposed to polycyclic aromatic hydrocarbons and related carcinogens in polluted environments.

Abstract: We evaluated humoral immunity by measuring IgG, IgA, IgM, and IgE concentrations in 274 male workers in an iron foundry in Cracow, Poland. There were two groups: 199 coke oven workers and 76 cold-rolling mill workers. The groups were similar with respect to age, length of work (average 15 years), and smoking habits. Exposure to polycyclic aromatic hydrocarbons (PAHs), assessed by personal and area monitoring, ranged from 0.2 to 50 micrograms/m3 benzo[a]pyrene in coke plant workers and was of 3-5 magnitudes higher than in the cold-rolling mill employees. Comparison of the two groups revealed a marked depression of mean serum IgG and IgA in coke oven workers (p < 0.001, Student's unpaired t-test). In the same subjects, serum IgM had a tendency to decrease, whereas serum IgE showed a trend toward higher values. Thus, workers exposed chronically to complex mixtures of air pollutants, composed primarily of PAHs, develop immunosuppression. It remains to be established whether the immunosuppression described here is related to the frequent development of lung cancer reported in coke plant employees. Workers exposed chronically to PAHs should have serum immunoglobulins monitored regularly.

Role of gastric blood flow, neutrophil infiltration, and mucosal cell proliferation in gastric adaptation to aspirin in the rat.

Abstract: Gastric mucosa exhibits the ability to adapt to ulcerogenic action of aspirin but the mechanism of this phenomenon is unknown. In this study, acute gastric lesions were produced by single or repeated doses of acidified aspirin in rats with intact or resected salivary glands and with intact or suppressed synthase of nitric oxide. A single oral dose of aspirin produced a dose dependent increase in gastric lesions accompanied by considerable blood neutrophilia and mucosal neutrophil infiltration, significant reduction in gastric blood flow, and almost complete suppression of biosynthesis of prostaglandins. After rechallenge with aspirin, the mucosal damage became smaller and progressively declined with repeated aspirin insults. Gastric adaptation to aspirin was accompanied by a significant rise in gastric blood flow, reduction in both blood neutrophilia and mucosal neutrophil infiltration, and a remarkable increase in mucosal cell regeneration and mucosal content of epidermal growth factor. Salivectomy, which reduced the mucosal content of epidermal growth factor, aggravated the initial mucosal damage induced by the first exposure to acidified aspirin but did not prevent the adaptation of this mucosa to repeated aspirin insults. Pretreatment with NG-nitro-L-arginine (L-NNA), a specific inhibitor of nitric oxide synthase, eliminated the hyperaemic response to repeated aspirin but did not abolish the development of adaptation to aspirin showing that the maintenance of the gastric blood flow plays little part in this adaptation. In conclusion, the stomach adapts readily to repeated aspirin insults and this is accompanied by a considerable reduction in blood neutrophilia and the severity of neutrophil infiltration and by an extensive proliferation of mucosal cells possibly involving epidermal growth factor.

Gravitating solitons and hairy black holes

Abstract: During the past few years there has been a lot of interest in soliton (by which I mean non-singular finite energy stationary solution) and black hole solutions of Einstein’s equationswith nonlinear field sources. In this brief survey I shall outline the most interesting,in my view, results of these studies

Antioxidant properties of plastoquinol and other biological prenylquinols in liposomes and solution.

Abstract: Oxidation of biological prenylquinols, like plastoquinol-9 (PQH2-9), ubiquinol-10 (UQH2-10), reduced vitamins K1(VK1H2) and K2(VK2H2), α-tocopherol quinol (α-TQH2) and α-tocopherol (α-T) was followed by their fluorescence during sonication of egg yolk lecithin/prenylquinol liposomes. The order of magnitude of oxidation of the prenylquinols by free radicals generated during sonication was VK2H2 VK1H2 α-TQH2 α-T. It was shown that egg yolk lecithin undergoes degradation even when sonicated briefly under atmosphere of nitrogen and at 0°C. A kinetic study of free radical scavenging action of the prenylquinols in solvents of different polarity was performed. The pseudo-first-order rate constants, k, for the reaction of the prenylquinols with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) in hexane showed that their scavenging activity changes in the order α-T> UQH2-10, being the highest in hexane and methanol, whereas in acetone and ethyl acetate the scavenging activity ...

The MHC class-II and CD44 molecules are involved in the induction of tumour necrosis factor (TNF) gene expression by human monocytes stimulated with tumour cells.

Abstract: Tumour necrosis factor alpha (TNF) mRNA is detected in the macrophage infiltrate surrounding the tumour, but the cellular/molecular interactions leading to TNF gene expression in macrophages are unknown. The in vitro system in which human blood monocytes are stimulated with human cancer cells for TNF release was used to study such interactions. Monoclonal antibodies (MAbs) against various adhesion molecules (LFA-1, LFA-3, ICAM-1, VNR, VLA beta I chain) were unable to block TNF production in co-culture of monocytes with a human pancreatic carcinoma (HPC) cell line. However, anti-CD44 and anti-HLA-DR MAbs effectively blocked TNF release and TNF-mRNA induction in monocytes. Pre-incubation of monocytes with anti-HLA-DR and tumour cells with anti-CD44 MAbs had a similar effect. It was concluded that CD44 molecules are involved in tumour-monocyte interactions and that HLA-DR determinants of monocytes are engaged in signal transduction for TNF gene activation. These findings may suggest that certain surface determinants of tumour cells act as ligands for MHC class-II molecules and induce TNF production in monocytes.

Differential effects of temperature on macrophages of ectothermic vertebrates.

Abstract: The role of macrophages in vertebrate defense reactions is especially important at low temperatures, which commonly affect representatives of ectothermic species. The aim of this work was to compare the effects of in vivo thermal acclimation and in vitro assay temper- atures on peritoneal macrophages (PMs) from fish (carp and goldfish) and amphibians (salamanders and toads). The substratum adherence of PMs was undisturbed over the wide range of temperatures experienced by animals in nature. Dehydrogenases and endocytosis were sensitive to temperature fluctuations in a species-specific manner, more or less dependent on the previous thermal history of animals. The MTT reduction, inhibited by low assay temperatures, was slightly improved in PMs from cold- acclimated amphibians but not fishes. Endocytosis by the amphibian PMs, very efficient over the wide range of as- say temperatures, was additionally improved by previous in vivo cold exposure. Contrasting effects of thermal ac- climation were most evident in the case of endocytic properties of fish PMs; endocytosis by PMs from cold- acclimated fishes was extraordinarily efficient at a tem- perature just above zero, which almost completely in- hibited cells from fishes adapted to warmth. J. Leukoc. Biol. 56: 729-731; 1994.

Effect of isolation stress on brain mast cells and brain histamine levels in rats

Abstract: The effects of the chronic social stress of isolation on changes in brain mast cells (MC), the hypothalamic histamine content and the activity of the hypothalamic-pituitary adrenal (HPA) axis were investigated in rats.

Some morphological and hormonal aspects of ovulation and superovulation in the rat

Abstract: In the first experiment, mature female Wistar rats, displaying a regular 4-day oestrous cycle, were killed in succession every 2 or 3 h on the day of pro-oestrus and oestrus until the time of ovulation. In the second experiment, immature female Wistar rats (aged 24 days) were injected s.c. with 30 IU pregnant mare serum gonadotrophin (PMSG) and 56 h later with 20 IU human chorionic gonadotrophin (hCG). They were killed in groups at 0, 24, 48, 56 and 57 h, and then every 2 h until 72 h. Excised ovaries were homogenized and analysed for steroid content or they were submitted to a routine histological procedure. The cyclic and PMSG/hCG-treated rats exhibited some similarities and differences in the general pattern of steroid content. Either a presumptive endogenous LH surge or administration of hCG resulted in an increase in the ovarian androgen concentration which preceded a rise in progesterone; the progesterone peak, in turn, was accompanied by a fall in the amount of androgens and oestradiol. However, in comparison with cyclic rats, superovulated animals displayed a significantly higher ovarian androgen level for a prolonged period; ovarian oestradiol concentration was also raised while the progesterone content was much lower. Histological analysis revealed large differences between the ovaries of superovulated and cyclic rats, especially with regard to the maturing follicles. The majority of PMSG/hCG-derived follicles showed hypertrophied theca interna and degenerated or luteinized granulosa. A large number of preovulatory follicles did not ovulate. These results clearly indicate that PMSG/hCG-induced follicles are not equal to the follicles developing during a normal oestrous cycle. This should be taken into consideration when using superovulated animals in experiments.

Invariant chaos in mixmaster cosmology.

Abstract: We discuss mathematical aspects of determining local instability parameters by using invariant characteristics of the internal pseudo-Riemannian geometry with the Jacobi metric (in principle, for Hamiltonian dynamical systems). Analytical formulas allowing one to compute the separation rate of nearby trajectories are given and the fundamental difference between the behavior of geodesics in the Riemannian and pseudo-Riemannian spaces carrying Jacobi metrics is stressed. The formalism developed here is used as an invariant tool to detect chaos in general relativity.

Growth of tomato seedlings under different HCO‐ 3 concentration in the medium

Abstract: An increase in the concentration of HCO‐ 3 ions in liquid media surrounding the root system significantly affected the biomass production of tomato seedlings in early stages of growth. This effect depended upon HCO‐ 3 concentration. The cultivation of seedlings during a period of 24 days (from 21–45 days after sowing) on a medium enriched to 5.68 mM HCO3 (0.025% CO2 after the computed dissociation) increased the production of dry matter (DW) plant"1 to about 179% as compared with the respective control. Various tomato organs showed different values of DW increase, the greatest one being noted in leaf blades. This result was correlated with an increase in leaf blade area to about 176% in relation to the control. With an increase in the concentration to 22.72 mM HCO‐ 3 (0.1% CO2 after the computed dissociation) a general tendency of changes was maintained, however, the absolute values of growth were diminished. In media of an enriched HCO3 content the length of shoots, and roots, was not significan...

Spin dosimetry in catalysis research

Abstract: Various aspects of the problem of reliability of the standards for spin dosimetry in solid samples containing transition metal ions are discussed. A method of preparing standards for d1 and d9 ions, based on vanadyl- and copper sulfate, is described. Reference samples with various spin concentration were prepared by uniform distribution of the paramagnetic substance in a diamagnetic, chemically unreactive matrix. The testing of the quality of standards was performed by statistical methods considering the following factors: reproducibility of the average chemical composition between preparations, macro- and microhomogeneity within preparations and precision of EPR measurements. The statistical analysis proved good quality of the standards produced by the elaborated method except for microinhomogeneity. Several examples are given to illustrate application of spin dosimetry in catalysis research. E.g., two different centers of reduced vanadium in vanadia-molybdena catalysts, V(IV) stabilized by oxygen vacancies and V(IV) stabilized by Mo(VI) ions, respectively, were identified. The kinetic model of redox processes occurring in V2O5−MoO3 catalysts upon interaction with oxygen and propylene was proposed. Quantitative determination of isolated Co(II) ions in CoO−MgO solid solutions revealed a strong correlation between the number of these ions and the amount of adsorbed O2− species.