Static tests of constructive tires using hydraulic press on the soil

ABSTRACT The power consumption and load capacity of agricultural machines have grown and the effects of pressure on the soil by tires have been still little investigated. In concern with sustainable development, the relationship machine-tire-soil must be in balance to give more consistency on the best use of tires for a given load. This study aimed to evaluate four tires of two constructive types, the bias belted tires and radial tires, both with respective rim diameters of 22.5 and 26.5 inches with variables measuring the footprint, elastic deformation, sinkage and resistance to penetration. A hydraulic press with an attachment shaft for tire mounting and a box of soil in which the tire has been imposed on a load of 53.00 kN using nominal pressures recommended by the tire manufacturer. The radial construction tire with rim diameter of 26.5 inches obtained less sinkage and resistance to penetration; however, greater elastic deformation and footprint compared to other tires. The bias-belted tire with 22.5-inch rim presented the highest resistance to penetration and the lowest elastic deformation.

Night admission is an independent risk factor for mortality in trauma patients - a systemic error approach

ABSTRACTObjective:to assess the impact of the shift inlet trauma patients, who underwent surgery, in-hospital mortality.Methods:a retrospective observational cohort study from November 2011 to March 2012, with data collected through electronic medical records. The following variables were statistically analyzed: age, gender, city of origin, marital status, admission to the risk classification (based on the Manchester Protocol), degree of contamination, time / admission round, admission day and hospital outcome.Results:during the study period, 563 patients injured victims underwent surgery, with a mean age of 35.5 years (± 20.7), 422 (75%) were male, with 276 (49.9%) received in the night shift and 205 (36.4%) on weekends. Patients admitted at night and on weekends had higher mortality [19 (6.9%) vs. 6 (2.2%), p=0.014, and 11 (5.4%) vs. 14 (3.9%), p=0.014, respectively]. In the multivariate analysis, independent predictors of mortality were the night admission (OR 3.15), the red risk classification (OR 4.87), and age (OR 1.17).Conclusion:the admission of night shift and weekend patients was associated with more severe and presented higher mortality rate. Admission to the night shift was an independent factor of surgical mortality in trauma patients, along with the red risk classification and age.

Jeg strikker, derfor er jeg! : læring og identitet i uformelle læringsrum

The dissertation ´I knit, therefore I am!´ Learning and identity in informal space has two main purposes. The first purpose being an investigation of how new value attributions and thinking can generate novel and usable knowledge to the field of craftsmanship, and the second purpose being a display of a different and overlooked philosophical and cultural potential in a reflexive mode of expression, which is able to reflect the normative comprehension of craftsmanship. The dissertation focuses on learning and identity in informal spaces of learning and how it is possible to relate such a learning perspective to crafts training in educational establishments. The empirical foundation of this dissertation is ‘craftivism’. In the dissertation activists from the Nordic countries have been interviewed about what they do when they put up their textile graffiti on lamp posts and house walls. Three research problems are presented: 1) What stories do people who work as crafts activists, tell about ways of relating and methods of action when they make crafts? 2) What do these stories tell about learning and identity? 3) How may the research results influence training and education in craftsmanship? These questions are being asked in order to acquire new knowledge in two aspects; first aspect being knowledge about crafts in relation to techniques, tradition and the objects in crafts, and the second aspect being knowledge about learning and identity in informal spaces of learning. The dissertations theoretical foundation is post structural and sociocultural combined with hermeneutical-inspired qualitative interviews. The author’s position and pre-understanding is subject to discussion in relation to the informant; the performing activist, as the background for both of them is craftsmanship. Starting from cultural studies, it is possible to see the activist subject’s conditions of possibilities in the culture, as the activism of the sub-cultural phenomenon’s craft lights up through a performing approach to the individual’s actions. First the research material has been analysed for events of textile graffiti and possible themes in the events, after which the results have been summarised. Next the research material has been analysed for events about learning and identity due to the author’s wish of comprehending the background of and motivational force in activism. The analysis is divided in main perspectives with different dimensions. The results of the analysis show the activist subject’s construction of an individual who actively takes part in a community by e.g. creating joy, changing the world’s perception of sustainability or by feminizing the public space. By taking crafts over the borders (and away from the class room) crafts become contextualized in a novel fashion thus obtaining an independent status. In this fashion the dissertation writes itself into a new method of comprehending and performing traditional craftsmanship techniques.

Communicative Purposes of Press Releases Announcing Reduction in Workforce

Tämä tutkielma käsittelee kaupallisten yhtiöiden julkaisemia lehdistötiedotteita, joissa ilmoitetaan henkilöstövähennyksistä. Erityisenä tutkimuskohteena ovat lehdistötiedotteiden informatiiviset ja promotionaaliset päämäärät ja tarkoitukset sekä näiden päämäärien ja tarkoitusten ilmentyminen tekstin retorisen rakenteen, valittujen retoristen strategioiden sekä leksikaalisten ja kieliopillisten valintojen kautta. Tutkimuksen aineisto koostuu 50 englanninkielisestä lehdistötiedotteesta, jotka sisältävät ilmoituksen henkilöstövähennyksistä. Lehdistötiedotteet kerättiin yritysten verkkosivuilta. Tutkimuksen teoreettisena viitekehityksenä toimivat soveltavan kielentutkimuksen alalla erityisesti ammattikielentutkimuksessa (ESP, English for Specific Purposes) laajalti käytetty Swalesin (1990) tekstilajia (genre) koskeva määritelmää ja Bhatian (1993) kehittämä geneerisen analyysin malli. Ennen aineiston kielitieteellistä analysointia tutkimuksessa perehdyttiin Bhatian (1993) mallin mukaisesti lehdistötiedotteiden historiaan, kohdeyleisöihin, diskurssiyhteisöön ja sen tuottamiin muihin tekstilajeihin, aikaisempiin lehdistotiedotteita käsitteleviin kielitieteellisiin tutkimuksiin sekä erityisesti yritysten henkilövähennyksiin liittyvään tilannekontekstiin. Kielitieteellisessä analyysissä tutkittavista teksteistä tunnistettiin kahdeksan retorista vaihetta (move), jotka olivat tyypillisiä tutkituille teksteille. Kunkin retorisen vaiheen yksittäiset ilmentymät koottiin yhteen erillisiksi aineistoiksi, joista pyrittiin tunnistamaan kullekin vaiheelle tyypilliset retoriset strategiat sekä toistuvat leksikaaliset ja kieliopilliset valinnat. Tutkimuksessa todettiin, että vaikka tutkittujen lehdistötiedotteiden pääasiallinen tarkoitus oli yhtiön toiminnasta tiedottaminen, niillä oli myös promotionaalinen päämäärä, joka ilmeni mm. pyrkimyksenä välittää yhtiöstä mahdollisimman positiivinen kuva eri kohdeyleisöille, erityisesti sijoittajille. Tämän positiivisen kuvan välittämiseen käytettyjä keinoja olivat mm. odotettavissa olevien saavutusten korostaminen, ulkoisten tekijöiden nimeäminen nykyisen tilanteen aiheuttajaksi, passiivin käyttö sekä erilaiset yrityksen julkisen kuvan säilyttämiseen pyrkivät (face-saving) strategiat.

Composite artistry in the Book of Numbers : a study in biblical narrative conventions

The present thesis discusses the coherence or lack of coherence in the book of Numbers, with special regard to its narrative features. The fragmented nature of Numbers is a well-known problem in research on the book, affecting how we approach and interpret it, but to date there has not been any thorough investigation of the narrative features of the work and how they might contribute to the coherence or the lack of coherence in the book. The discussion is pursued in light of narrative theory, and especially in connection to three parameters that are typically understood to be invoked in the interpretation of narratives: 1) a narrative paradigm, or ‘story,’ meaning events related to each other temporally, causally, and thematically, in a plot with a beginning, middle, and end; 2) discourse, being the expression plane of a narrative, or the devices that an author has at hand in constructing a narrative; 3) the situation or languagegame of the narrative, prototypical examples being factual reports, which seeks to depict a state of affairs, and storytelling narratives, driven by a demand for tellability. In view of these parameters the present thesis argues that it is reasonable to form four groups to describe the narrative material of Numbers: genuine narratives (e.g. Num 12), independent narrative sequences (e.g. Num 5:1-4), instrumental scenes and situations (e.g. Num 27:1-5), and narrative fragments (e.g. Num 18:1). These groups are mixed throughout with non-narrative materials. Seen together, however, the narrative features of these groups can be understood to create an attenuated narrative sequence from beginning to end in Numbers, where one thing happens after another. This sequence, termed the ‘larger story’ of Numbers, concerns the wandering of Israel from Sinai to Moab. Furthermore, the larger story has a fragmented plot. The end-point is fixed on the promised land, Israel prepares for the wandering towards it (Num 1-10), rebels against wandering and the promise and is sent back into the wilderness (Num 13-14), returns again after forty years (Num 21ff.), and prepares for conquering the land (Num 22-36). Finally, themes of the promised land, generational succession, and obedience-disobedience, operate in this larger story. Purity is also a significant theme in the book, albeit not connected to plot in the larger story. All in all, sequence, plot, and theme in the larger story of Numbers can be understood to bring some coherence to the book. However, neither aspect entirely subsumes the whole book, and the four groups of narrative materials can also be understood to underscore the incoherence of the work in differentiating its variegated narrative contents. Numbers should therefore be described as an anthology of different materials that are loosely connected through its narrative features in the larger story, with the aim of informing Israelite identity by depicting a certain period in the early history of the people.

Puolueiden keskustelutilaisuuksista mediatapahtumiksi. Television vaaliohjelmat ja niihin liittynyt sanomalehtijulkisuus 1960-luvulta 1980-luvulle

Tässä tutkimuksessa tarkastellaan television vaaliohjelmia ja niihin liittynyttä sanomalehtijulkisuutta 1960-luvun alusta 1980-luvun lopulle. Tarkastelun kohteena ovat sekä eduskunta- että presidentinvaalien vaaliohjelmat. Tutkimusaineisto koostuu Yleisradion hallinto- ja ohjelmaneuvostojen pöytäkirjoista, vaaliohjelmien televisiotallenteista sekä vaaliohjelmia käsittelevistä sanomalehtikirjoituksista. Lehtiaineisto on kerätty Helsingin Sanomista, Ilta-Sanomista, Iltalehdestä, Aamulehdestä, Kansan Uutisista, Suomenmaasta sekä Suomen Sosialidemokraatista. Sanomalehtiaineistoa on täydennetty Yleisradion leikearkistoon kerätyillä lehtileikkeillä. Tutkimuksessa on analysoitu toisaalta television vaaliohjelmien kehitystä ja toisaalta vaaliohjelmiin liittynyttä sanomalehtikirjoittelua. Television vaaliohjelmien kehityksen osalta tutkimuksessa on kuvattu, millä tavoin vaaliohjelmia on eri aikoina tehty ja millaisia poliittisia kiistoja niiden tekemiseen on liittynyt. Sanomalehtiaineiston analyysissa on tarkasteltu sitä, mihin seikkoihin vaaliohjelmia käsittelevissä kirjoituksissa on kiinnitetty huomiota, millä tavoin lehdet ovat suhtautuneet ohjelmien toteutukseen ja millainen rooli ohjelmilla on nähty olleen vaalikampanjoinnissa. Väitöskirjan näkökulma on historiallinen, mikä merkitsee ajallisten kontekstien keskeisyyttä analyysissa. Tutkimuksessa on kiinnitetty huomiota sekä poliittisessa kulttuurissa että mediamaisemassa tapahtuneisiin muutoksiin. Vaaliohjelmat olivat 1960-luvulla tarkkaan säänneltyjä puolueiden välisiä keskustelutilaisuuksia, joissa toimittajilla ei ollut näkyvää roolia. Ohjelmien toteutuksesta vastasivat puoluemandaateilla toimineet Yleisradion ohjelma- ja hallintoneuvoston jäsenet, joten ohjelmien toteutuksen yksityiskohdista vastasivat puolueet. Puolueet riitelivät usein vaaliohjelmien toteutuksesta, mikä osoittaa, että puolueille television vaaliohjelmat olivat tärkeitä poliittisia foorumeita jo 1960-luvulta lähtien. Vaaliohjelmat jakautuivat kahteen erilaiseen ohjelmaformaattiin; vaalitentteihin ja suureen vaalikeskusteluun. Vaalitenteissä kunkin puolueen edustajat olivat vuorollaan ”altavastaajina”, joille muiden puolueiden edustajat esittivät kysymyksiä. Suuri vaalikeskustelu oli perinteisempi paneelikeskustelu, jossa poliitikot selvittivät vuorotellen kantojaan ajankohtaisiin poliittisin kysymyksiin. 1970-luvun puolivälissä vaalitenttien toteutuksessa tapahtui suuria muutoksia, kun toimittajat syrjäyttivät poliitikot vaalitenttien kyselijöinä. Suuri vaalikeskustelu säilyi ennallaan. Sanomalehtien suhtautuminen vaaliohjelmiin oli 1960- ja 1970-luvuilla huomattavasti pidättyvämpää kuin poliitikkojen. Sanomalehdistön näkökulmasta television vaaliohjelmien tärkeimpänä tehtävänä oli puolueiden poliittisten linjausten esittely. Vaaliohjelmia käsittelevissä teksteissä esiteltiin pääasiassa poliitikkojen ohjelmissa pitämiä puheenvuoroja. Puoluelehdissä puheenvuorojen sisältöä arvioitiin aatteellisista lähtökohdista, sitoutumattomissa sanomalehdissä neutraalimmin. Vaaliohjelmien toteutukseen liittynyt kritiikki kohdistui toisaalta poliitikkojen puoluepropagandaan, toisaalta poliitikkojen liialliseen varovaisuuteen. Sanomalehtien suhtautuminen vaaliohjelmiin säilyi ennallaan myös 1970-luvulla, jolloin vaaliohjelmia alettiin tehdä toimittajavetoisesti. Ainoa muutos liittyi vaaliohjelmakritiikkiin, joka kohdistui nyt poliitikkojen ohella myös toimittajiin, joiden katsottiin olleen ohjelmissa liian hyökkääviä. Suurin muutos vaaliohjelmiin liittyneessä kirjoittelussa tapahtui 1980-luvulla. Vaaliohjelmia käsitteleviä kirjoituksia julkaistiin sanomalehdistössä monikertainen määrä 1970-lukuun verrattuna. Samalla myös vaaliohjelmia käsittelevien kirjoitusten näkökulmat alkoivat muuttua, kun ohjelmin visuaalinen ulottuvuus alkoi olla yhä näkyvämmin esillä sanomalehtiin laadituissa analyyseissa. Lehdet alkoivat teettää säännöllisesti erilaisia tutkimuksia poliitikkojen pärjäämisestä ohjelmissa ja kirjoittaa vaalikeskusteluiden voittajista ja häviäjistä. Lisäksi lehtijutuissa arvioitiin poliitikkojen esiintymistä ja vaaliohjelmista välittyviä vaikutelmia. Vuoden 1982 presidentinvaaleissa uusista näkökulmista kirjoittivat erityisesti iltapäivälehdet, mutta vuosikymmenen jälkipuoliskolla samankaltaisia lähestymistapoja omaksuivat myös Helsingin Sanomat ja Aamulehti. Niiden vaaliohjelmia käsittelevissä uutisissa kiinnitettiin yhä useammin huomiota poliitikkojen esiintymiseen, pukeutumiseen ja tunnetiloihin. Puoluelehtien suhtautuminen vaaliohjelmiin säilyi kuitenkin ennallaan, ja myös vaaliohjelmakritiikki säilyi suurelta osin muuttumattomana. 1980-luvun aikana television vaaliohjelmat muuttuivat lehdistön käsittelyssä puolueiden tavoitteita esittelevistä keskustelutilaisuuksista poliitikkojen ja puolue johtajien henkilökohtaisia ominaisuuksia mittaaviksi esiintymiskokeiksi ja suuriksi mediatapahtumiksi, joiden katsottiin toisinaan jopa ratkaisseen vaalin tuloksen. Nostaessaan television vaaliohjelmat kampanjajournalisminsa ytimeen, sanomalehdet vahvistivat television poliittista roolia.

Letters from the War of Ecosystems – An Analysis of Independent Software Vendors in Mobile Application Marketplaces

The recent emergence of a new generation of mobile application marketplaces has changed the business in the mobile ecosystems. The marketplaces have gathered over a million applications by hundreds of thousands of application developers and publishers. Thus, software ecosystems—consisting of developers, consumers and the orchestrator—have emerged as a part of the mobile ecosystem. This dissertation addresses the new challenges faced by mobile application developers in the new ecosystems through empirical methods. By using the theories of two-sided markets and business ecosystems as the basis, the thesis assesses monetization and value creation in the market as well as the impact of electronic Word-of-Mouth (eWOM) and developer multihoming— i. e. contributing for more than one platform—in the ecosystems. The data for the study was collected with web crawling from the three biggest marketplaces: Apple App Store, Google Play and Windows Phone Store. The dissertation consists of six individual articles. The results of the studies show a gap in monetization among the studied applications, while a majority of applications are produced by small or micro-enterprises. The study finds only weak support for the impact of eWOM on the sales of an application in the studied ecosystem. Finally, the study reveals a clear difference in the multi-homing rates between the top application developers and the rest. This has, as discussed in the thesis, an impact on the future market analyses—it seems that the smart device market can sustain several parallel application marketplaces.

Butyrate induces apoptosis in murine macrophages via caspase-3, but independent of autocrine synthesis of tumor necrosis factor and nitric oxide

We demonstrated that 4 mM butyrate induces apoptosis in murine peritoneal macrophages in a dose- and time-dependent manner as indicated by studies of cell viability, flow cytometric analysis of annexin-V binding, DNA ladder pattern and the determination of hypodiploid DNA content. The activity of caspase-3 was enhanced during macrophage apoptosis induced by butyrate and the caspase inhibitor z-VAD-FMK (100 µM) inhibited the butyrate effect, indicating the major role of the caspase cascade in the process. The levels of butyrate-induced apoptosis in macrophages were enhanced by co-treatment with 1 µg/ml bacterial lipopolysaccharide (LPS). However, our data indicate that apoptosis induced by butyrate and LPS involves different mechanisms. Thus, LPS-induced apoptosis was only observed when macrophages were primed with IFN-gamma and was partially dependent on iNOS, TNFR1 and IRF-1 functions as determined in experiments employing macrophages from various knockout mice. In contrast, butyrate-induced macrophage apoptosis was highly independent of IFN-gamma priming and of iNOS, TNFR1 and IRF-1 functions.

c-Myc protein expression is not an independent prognostic predictor in cervical squamous cell carcinoma

The c-myc protein is known to regulate the cell cycle, and its down-regulation can lead to cell death by apoptosis. The role of c-myc protein as an independent prognostic determinant in cervical cancer is controversial. In the present study, a cohort of 220 Brazilian women (mean age 53.4 years) with FIGO stage I, II and III (21, 28 and 51%, respectively) cervical squamous cell carcinomas was analyzed for c-myc protein expression using immunohistochemistry. The disease-free survival and relapse-rate were analyzed using univariate (Kaplan-Meier) survival analysis for 116 women who completed the standard FIGO treatment and were followed up for 5 years. Positive c-myc staining was detected in 40% of carcinomas, 29% being grade 1, 9% grade 2, and 2% grade 3. The distribution of positive c-myc according to FIGO stage was 19% (17 women) in stage I, 33% (29) in stage II, and 48% (43) in stage III of disease. During the 60-month follow-up, disease-free survival in univariate (Kaplan-Meier) survival analysis (116 women) was lower for women with c-myc-positive tumors, i.e., 60.5, 47.5 and 36.6% at 12, 36, and 60 months, respectively (not significant). The present data suggest that immunohistochemical demonstration of c-myc does not possess any prognostic value independent of FIGO stage, and as such is unlikely to be a useful prognostic marker in cervical squamous cell carcinoma.

Thiol-independent activity of a cholesterol-binding enterohemolysin produced by enteropathogenic Escherichia coli

Enterohemolysin produced by Escherichia coli associated with infant diarrhea showed characteristics similar to those of thiol-activated hemolysins produced by Gram-positive bacteria, including inactivation by cholesterol, lytic activity towards eukaryotic cells and thermoinstability. However, enterohemolysin activity was not inactivated by oxidation or by SH group-blocking agents (1 mM HgCl2, 1 mM iodoacetic acid) and the hemolysin (100 µg/ml) was not lethal to mice, in contrast to the lethality of the thiol-activated hemolysin family to animals. Earlier reports showed that intravenous injection of partially purified streptolysin O preparations (0.2 µg) was rapidly lethal to mice. These results suggest that E. coli enterohemolysin is not a thiol-activated hemolysin, despite its ability to bind cholesterol, probably due to the absence of free thiol-group(s) that characterize the active form of the thiol-activated hemolysin molecule.

Possibility of press forming wood films into primary packaging

In recent times the packaging industry is finding means to maximize profit. Wood used to be the most advantageous and everyday material for packaging, worktables, counters, constructions, interiors, tools and as materials and utensils in the food companies in the world. The use of wood has declined vigorously, and other materials like plastic, ceramic, stainless steel, concrete, and aluminum have taken its place. One way that the industry could reduce its cost is by finding possibilities of using wood for primary packaging after which it can be safely recycled or burned as a carbon source for energy. Therefore, the main objective of this thesis is to investigate the possibility of press-forming a wood film into primary packaging. In order to achieve the stated objectives, discussion on major characteristics of wood in terms of structure, types and application were studied. Two different wood species, pine and birch were used for the experimental work. These were provided by a local carpentry workshop in Lappeenranta and a workshop in Ruokolahti supervised by Professor Timo Kärki. Laboratory tests were carried out at Lappeenranta University of Technology FMS workshop on Stenhøj EPS40 M hydraulic C-frame press coupled with National Instruments VI Logger and on the Adjustable packaging line machine at LUT Packaging laboratory. The tests succeeded better on the LUT packaging line than on the Stenhoj equipment due to the integrated heating system in the machine. However, there is much work to be done before the quality of a tray produced from the wood film is comparable to that of the wood plastic composite tray.

The action of red wine and purple grape juice on vascular reactivity is independent of plasma lipids in hypercholesterolemic patients

Although red wine (RW) reduces cardiovascular risk, the mechanisms underlying the effect have not been identified. Correction of endothelial dysfunction by RW flavonoids could be one mechanism. We measured brachial artery reactivity by high-resolution ultrasonography, plasma lipids, glucose, adhesion molecules (ICAM-1 and VCAM), and platelet function in 16 hypercholesterolemic individuals (8 men and 8 women; mean age 51.6 ± 8.1 years) without other risk factors. Twenty-four normal subjects were used as controls for vascular reactivity. Subjects randomly received RW, 250 ml/day, or purple grape juice (GJ), 500 ml/day, for 14 days with an equal wash-out period. At baseline, all 16 subjects were hypercholesterolemic (mean LDL = 181.0 ± 28.7 mg/dl) but HDL, triglycerides, glucose, adhesion molecules, and platelet function were within normal limits. Brachial artery flow-mediated dilation was significantly decreased compared to controls (9.0 ± 7.1 vs 12.1 ± 4.5%; P < 0.05) and increased with both GJ (10.1 ± 7.1 before vs 16.9 ± 6.7% after: P < 0.05) and RW (10.1 ± 6.4 before vs 15.6 ± 4.6% after; P < 0.05). RW, but not GJ, also significantly increased endothelium-independent vasodilation (17.0 ± 8.6 before vs 23.0 ± 12.0% after; P < 0.01). GJ reduced ICAM-1 but not VCAM and RW had no effect on either molecule. No significant alterations were observed in plasma lipids, glucose or platelet aggregability with RW or GJ. Both RW and GJ similarly improved flow-mediated dilation, but RW also enhanced endothelium-independent vasodilation in hypercholesterolemic patients despite the increased plasma cholesterol. Thus, we conclude that GJ may protect against coronary artery disease without the additional negative effects of alcohol despite the gender.

Ureases display biological effects independent of enzymatic activity: Is there a connection to diseases caused by urease-producing bacteria?

Ureases are enzymes from plants, fungi and bacteria that catalyze the hydrolysis of urea to form ammonia and carbon dioxide. While fungal and plant ureases are homo-oligomers of 90-kDa subunits, bacterial ureases are multimers of two or three subunit complexes. We showed that some isoforms of jack bean urease, canatoxin and the classical urease, bind to glycoconjugates and induce platelet aggregation. Canatoxin also promotes release of histamine from mast cells, insulin from pancreatic cells and neurotransmitters from brain synaptosomes. In vivo it induces rat paw edema and neutrophil chemotaxis. These effects are independent of ureolytic activity and require activation of eicosanoid metabolism and calcium channels. Helicobacter pylori, a Gram-negative bacterium that colonizes the human stomach mucosa, causes gastric ulcers and cancer by a mechanism that is not understood. H. pylori produces factors that damage gastric epithelial cells, such as the vacuolating cytotoxin VacA, the cytotoxin-associated protein CagA, and a urease (up to 10% of bacterial protein) that neutralizes the acidic medium permitting its survival in the stomach. H. pylori whole cells or extracts of its water-soluble proteins promote inflammation, activate neutrophils and induce the release of cytokines. In this paper we review data from the literature suggesting that H. pylori urease displays many of the biological activities observed for jack bean ureases and show that bacterial ureases have a secretagogue effect modulated by eicosanoid metabolites through lipoxygenase pathways. These findings could be relevant to the elucidation of the role of urease in the pathogenesis of the gastrointestinal disease caused by H. pylori.

Endothelium-dependent and -independent hepatic artery vasodilatation is not impaired in a canine model of liver ischemia-reperfusion injury

We investigated whether hepatic artery endothelium may be the earliest site of injury consequent to liver ischemia and reperfusion. Twenty-four heartworm-free mongrel dogs of either sex exposed to liver ischemia/reperfusion in vivo were randomized into four experimental groups (N = 6): a) control, sham-operated dogs, b) dogs subjected to 60 min of ischemia, c) dogs subjected to 30 min of ischemia and 60 min of reperfusion, and d) animals subjected to 45 min of ischemia and 120 min of reperfusion. The nitric oxide endothelium-dependent relaxation of hepatic artery rings contracted with prostaglandin F2a and exposed to increasing concentrations of acetylcholine, calcium ionophore A23187, sodium fluoride, phospholipase-C, poly-L-arginine, isoproterenol, and sodium nitroprusside was evaluated in organ-chamber experiments. Lipid peroxidation was estimated by malondialdehyde activity in liver tissue samples and by blood lactic dehydrogenase (LDH), serum aspartate aminotransferase (AST) and serum alanine aminotransferase (ALT) activities. No changes were observed in hepatic artery relaxation for any agonist tested. The group subjected to 45 min of ischemia and 120 min of reperfusion presented marked increases of serum aminotransferases (ALT = 2989 ± 1056 U/L and AST = 1268 ± 371 U/L; P < 0.01), LDH = 2887 ± 1213 IU/L; P < 0.01) and malondialdehyde in liver samples (0.360 ± 0.020 nmol/mgPT; P < 0.05). Under the experimental conditions utilized, no abnormal changes in hepatic arterial vasoreactivity were observed: endothelium-dependent and independent hepatic artery vasodilation were not impaired in this canine model of ischemia/reperfusion injury. In contrast to other vital organs and in the ischemia/reperfusion injury environment, dysfunction of the main artery endothelium is not the first site of reperfusion injury.