Browsing by Subject "endotoksiini"

Tutkimuksen tarkoituksena oli selvittää Escherichia colimastiitin patogeneesia sekä antibioottihoidon vaikutusta taudin kulkuun ja bakteerien eliminoitumiseen utareesta. Työn ensimmäisessä osassa aiheutettiin kokeellinen mastiitti neljälle ayshire-lehmälle inokuloimalla yhteen neljännekseen kahdella eri tartutuskerralla 10³ CFU Escherichia coli-bakteeria. Joka toisella tartutuskerralla hoitona oli vain lypsy oksitosiinin avulla ja joka toisella tartutuskerralla lypsyn lisäksi parenteraalinen antibioottihoito (trimetopriimi-sulfadiatsiini). Tulehdusparametrejä ja lehmien kliinistä tilaa seurattiin jatkuvasti sekä akuutin taudin että paranemisen edistyessä. Tulehdusreaktio oli huipussaan 12 tunnin kuluttua tartutuksesta ja kaikki tulehdusparametriarvot laskivat normaalitasolle kolmen viikon kuluessa. Antitrypsiiniaktiivisuus tosin oli huipussaan jo kahdeksan tunnin kuluttua tartutuksesta ja se laski normaalitasolle kaikilla lehmillä kahden viikon kuluessa. Bakteerit eliminoituivat utareesta viikon kuluessa, samoin endotoksiinit. Sairastuvuudessa, taudin vakavuudessa tai paranemisnopeudessa ei voitu todeta eroa eri hoitojen tai tartutuskertojen välillä. Toinen osatutkimus käsitti 47 spontaania akuuttia koliformimastiittia. Sairaan neljänneksen maidosta määritettiin NAGaasi- ja antitrypsiiniaktiivisuudet sekä endotoksiinipitoisuus semikvantitatiivisesti. Tässä ryhmässä esiintyi yleisesti hyvin korkeita NAGaasi- ja antitrypsiiniaktiivisuuksia ja endotoksiinia löytyi useimmista näytteistä.

Idiosyncratic drug reaction denotes a non-immunological hypersensitivity to a substance unrelated to drug toxicity. Idiosyncratic drug reactions occur rarely and unpredictably amongst drug users. Endotoxins (lipopolysaccharides) are a part of the outer membrane of the cell wall of Gram-negative bacteria. Endotoxins may cause fever, leukopenia, and shock depending on the bacterial species and the health of the infected person. Usually endotoxins first insult the liver, a key detoxication organ in the host. Endotoxins can provoke Kuppfer cells to release pro-inflammatory cytokines, such as tumour necrosis factor alpha (TNF-α) and interleukin-1 (IL-1), which can lead to systemic inflammatory response and damage liver. Inflammation and liver damage can sensitize to idiosyncratic drug reactions. Endotoxin tolerance is defined as a reduced responsiveness to a lipopolysaccharide (LPS) challenge following the first encounter with endotoxin. Endotoxin tolerance is associated with a reduction of tumor necrosis factor alpha and interleukin-1 production in response to LPS. Endotoxin tolerance protects against a lethal challenge of LPS and prevents infection-inflicted tissue damage. The aim of this study was to determine such a dose and time-point after exposure which lead to a mild liver lesion and to increased hepatic levels of TNF-α and IL-1 mRNA in rats. We also made an attempt to induce endotoxin tolerance. 38 laboratory rats were used and studied in three rat groups. TNF-α and IL-1 levels were analyzed from rats killed 1, 3, 6, 12 or 24 h after endotoxin (1.0 mg/kg) given intraperitoneally. Endotoxin treatment resulted in significantly increased levels of TNF- α:n and IL-1 mRNA in all endotoxin-treated rats. Serum ASAT and ALAT levels also increased at 24 h. These results are consistent with tissue damage and inflammation in the liver. We failed to induce a clear endotoxin tolerance. The dose used (0,5 mg/kg) dose may have been too large for that.

Gut inflammation and permeability is speculated to play a major role in the pathophysiology of several human diseases. Signs of a low-grade gut inflammation in patients with type 1 diabetes (T1D) have been found. Focus of this study was to understand the role of gut inflammation and increased gut permeability in the development of diabetic complications, especially nephropathy. Approximately, one-third of Finnish patients with T1D develop kidney disease during their lifetime. Inflammatory mechanisms may have an essential role in the pathophysiology of the disease. Lipopolysaccharide, LPS, is found in the outer membrane of gram-negative bacteria. LPS activates innate immune system and triggers the activation of inflammatory cytokines, neutrophils and macrophages as well as many pathophysiological processes in vivo, for instance fever and endotoxic shock. Aim of this study was to establish a zebrafish gut inflammation model using fluorophore conjugated endotoxin, LPS. We hypothesized that delivery of LPS in addition to EDTA in the gut of zebrafish triggers inflammation and increased gut permeability which may lead to leakage of LPS to blood stream and potentially kidney injury. This novel zebrafish inflammation model could possibly be used for studying the pathophysiological mechanisms of gut inflammation and possible kidney injury as well as for screening new anti-inflammatory drugs. In addition, this animal model can be used for studying intestinal alkaline phosphatase (IAP) in reducing gut permeability and LPS-mediated kidney damage. IAP is an enzyme produced in small-intestinal epithelium. IAP can detoxify several bacterial endotoxins including LPS and thus protect against the induction of intestinal inflammation. LPS and EDTA were delivered in the gut of 6 days old zebrafish larvae using microgavage injection. Fluorescence microscopy imaging of live zebrafish enabled following the same individual at different timepoints after injections. Paraffin sectioning of the small larvae was promising for investigating the morphology and permeability of the gut as well as possible immunostaining for detection of IAP. L-phenylalanine was used for inhibition of IAP enzyme. Using the novel method of microinjection to gut on zebrafish larvae the timing and amount of delivered materials to gut can be controlled well. The anatomy and function of the gut in zebrafish is very similar to small intestine of mammals and the highly developed vertebrate immune system makes zebrafish an interesting model organism for studying gut inflammation and permeability. In addition, inflammatory processes can be visualized in live, intact transparent zebrafish larvae. However, the technique has a lot of challenges including small size of the fish and possible tissue damage of the fish while performing injection. More experiments need to be carried out to establish the model for drug screening. Also, along with microscopy images, a more precise way for quantification the gut permeability is needed. Based on the images it’s not yet possible to conclude whether LPS increased gut permeability or if IAP inhibition with L-phenylalanine worked in zebrafish larvae. Using adult zebrafish in the future will give more information about the chronic gut inflammation and development of possible kidney injury.