Authors:Greta Gölz, Gül Karadas, André Fischer, Ulf B. Göbel, Thomas Alter, Stefan Bereswill, and Markus M. Heimesaat
Arcobacter butzleri causes sporadic cases of gastroenteritis, but the underlying immunopathological mechanisms of infection are unknown. We have recently demonstrated that A. butzleri-infected gnotobiotic IL-10−/− mice were clinically unaffected but exhibited intestinal and systemic inflammatory immune responses. For the first time, we here investigated the role of Toll-like receptor (TLR)-4, the main receptor for lipopolysaccharide and lipooligosaccharide of Gram-negative bacteria, in murine arcobacteriosis. Gnotobiotic TLR-4/IL-10-double deficient (TLR-4−/− IL-10−/−) and IL-10−/− control mice generated by broad-spectrum antibiotics were perorally infected with A. butzleri. Until day 16 postinfection, mice of either genotype were stably colonized with the pathogen, but fecal bacterial loads were approximately 0.5–2.0 log lower in TLR-4−/− IL-10−/− as compared to IL-10−/− mice. A. butzleri-infected TLR-4−/− IL-10−/− mice displayed less pronounced colonic apoptosis accompanied by lower numbers of macrophages and monocytes, T lymphocytes, regulatory T-cells, and B lymphocytes within the colonic mucosa and lamina propria as compared to IL-10−/− mice. Furthermore, colonic concentrations of nitric oxide, TNF, IL-6, MCP-1, and, remarkably, IFN-γ and IL-12p70 serum levels were lower in A. butzleri-infected TLR-4−/− IL-10−/− versus IL-10−/− mice. In conclusion, TLR-4 is involved in mediating murine A. butzleri infection. Further studies are needed to investigate the molecular mechanisms underlying Arcobacter—host interactions in more detail.
Authors:Fulya Üstün Alkan, Tülay Bakirel, Oya Üstüner, and Hasret Yardibi
The present study evaluated the effects of doxorubicin (DOX) and deracoxib (DER), as single agents and in combination treatments, on antioxidant parameters in the canine mammary carcinoma cell line CMT-U27. The cells were exposed to DOX and DER for 24, 48 and 72 h. The viability and malondialdehyde (MDA), nitric oxide (NO), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and total glutathione (GSH) activities of CMT-U27 cells were determined. The half inhibition concentration (IC50) of DOX was found to be ∼0.9 μM in the 72-h period. IC50 and 1/10 IC50 concentrations of DOX were combined with all concentrations of DER (50–1000 μM) in the combination experiments. The results showed increased oxidative status associated with significant decreases of CAT and GSH levels in CMT-U27 cells exposed to 10-μM and higher concentrations of DOX compared to control cells. In contrast, there were no significant changes in the groups tested with any of the concentrations of DER (50–1000 μM). In combination treatments, DER attenuated DOX-induced oxidative damage by modulating the enzymatic and non-enzymatic components in CMT-U27 cells. We suggest that the combination of DOX and DER can be beneficial in the treatment of cancer cells by increasing cellular responses to oxidative stress. In conclusion, the use of COX inhibitor in conjunction with a chemotherapeutic agent may provide a basis for new concepts of cancer treatment through systematic modulation of the antioxidant defence systems in mammary cancers of animals.
Authors:Anne Grunau, Ulrike Escher, Stefan Bereswill, and Markus M. Heimesaat
The rising incidences of infections with multidrug-resistant (MDR) Gram-negative bacteria including Pseudomonas aeruginosa (PA) have gained increasing attention in medicine, but also in the general public and global health politics. The mechanisms underlying opportunistic pathogen—host interactions are unclear, however. To address this, we challenged secondary abiotic IL10−/− mice deficient for Toll-like receptor-4 (TLR4−/− × IL10−/−), the main receptor of the Gram-negative cell wall constituent lipopolysaccharide, with a clinical MDR PA isolate. Despite higher intestinal colonization densities, apoptotic colonic epithelial cell numbers were lower in TLR4−/− × IL10−/− mice as compared to IL10−/− controls at day 14 postinfection (p.i.), whereas proliferating/regenerating cells had increased in the latter only. Furthermore, PA-colonized TLR4−/− × IL10−/− mice displayed less distinct innate and adaptive immune cell responses in the colon as compared to IL10−/− counterparts that were accompanied by lower nitric oxide concentrations in mesenteric lymph nodes in the former at day 14 p.i. Conversely, splenic NO levels were higher in both naive and PA-colonized TLR4-deficient IL10−/− mice versus IL10−/− controls. Remarkably, intestinal MDR PA was able to translocate to extra-intestinal including systemic compartments of TLR4−/− × IL10−/− mice only. Hence, MDR PA-induced intestinal and systemic immune responses observed in secondary abiotic IL10−/− mice are TLR4-dependent.
Authors:K. Rajagopalan, P. Ravindran, and T. Radhakrishnan
TG-DTA-EGA studies have shown that anhydrous uranyl nitrate cannot be obtained by thermal decomposition of uranyl nitrate
hexahydrate. Hydrolysis and polymerization of the salt during dehydration resulted in hydroxynitrates which decomposed in
multiple steps with the evolution of oxides of nitrogen and water. The extent of hydrolysis dependend on the sample size,
heating rate and nature of sample containment. Large samples on decomposition at relatively high heating rates showed evolution
of nitric oxide even above 500°C. Infrared studies on the residues prepared at various temperatures supported the conclusions.
The hyphenated thermal analysis-mass spectrometry
technique (TA-MS) was applied for the investigation of the thermal behavior
of reference and aged parchment samples. The kinetic parameters of the process
were calculated independently from all recorded TA and MS signals. The kinetic
analysis showed the distinct dependence of the activation energy on the reaction
progress. Such behavior is characteristic for the multistage mechanism of
The comparison of the kinetic parameters calculated
from the different signals i.e. TG, DSC, MS for H2O,
NO and CO2, however, indicated that they were differently
dependent on the aging of the sample. For the parchment samples, the aging
almost does not change the kinetics of the decomposition calculated from the
DSC data: the influence of aging seems to be too negligible to be detected
by these techniques. On the other hand, the much more sensitive mass spectrometric
technique applied to the kinetic analysis allowed monitoring of visible changes
in the thermal behavior of the parchment samples due to the aging process.
The influence of aging was especially visible when the MS signals of water
and nitric oxide were applied for the determination of the kinetic parameters.
The applied method of the kinetic analysis allowed also the prediction
of the thermal behaviour of reference and aged parchment samples under isothermal
and modulated temperature conditions. Presented results have confirmed the
usefulness of thermoanalytical methods for investigating behaviour of such
complicated systems as leather or parchment.
Authors:A. Altınok, Z.M. Coşkun, K. Karaoğlu, S. Bolkent, A.G. Akkan, and S. Özyazgan
In this study, we investigated the possible effect of Δ9-tetrahydrocannabinol (THC), a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, on metabolic control and vascular complications of diabetes in streptozotocin/nicotinamide (STZ/NIC) induced type 2 diabetes mellitus.
Material and methods
Type 2 diabetes was induced with 65 mg/kg STZ, 15 minute later 85 mg/kg NIC was given intraperitoneally (i.p.) to rats. Three days after diabetes induction, THC (3 mg/kg/day, i.p.) was given for 7 days to diabetic rats. Body weight and plasma glucose levels of rats were measured in all groups before and at the end of 3 weeks after diabetes induction. Acetylcholine (Ach) and sodium nitroprusside (SNP) potency and maximum relaxant effects were calculated on aortic rings pre-contracted with noradrenaline (NA).
At the end of 3 weeks, blood glucose levels of diabetic group significantly increased in comparison with the control group. Increased plasma glucose levels were significantly decreased by the treatment of THC. Ach induced relaxation was impaired whereas endothelium-independent relaxation to SNP was unaffected on isolated diabetic rat aorta. THC treatment enhanced Ach induced relaxation on diabetic rat aortas.
These results suggested that THC improved endothelium-dependent relaxation in STZ/NIC induced diabetic rat aorta and that these effects were mediated at least in part, by control of hyperglycemia and enhanced endothelial nitric oxide bioavailability.
Authors:M Ninković, M Ninković, M Ninković, Z Maličević, Z Maličević, Z Maličević, A Jelenković, A Jelenković, A Jelenković, DM Jovanović, DM Jovanović, DM Jovanović, M Đukić, M Đukić, M Đukić, I Vasiljević, I Vasiljević, and I Vasiljević
a part of blood-brain barrier, brain capillaries participate in
pathophysiological events during systemic inflammation. We investigated the
effects of 7-nitroindazole (7-NI), selective neuronal nitric oxide synthase
(NOS) inhibitor, to oxidative status (OS) of brain capillaries. Adult Wistar
rats were randomized at groups: control group (CG) (sham operated), sepsis
group (GS) (cecal ligation and perforation with inoculation of Escherichia
coli (ATCC 25922), 7-NI group (G7-NI), (30 mg/kg b/w i. p.) and 7-NI +
sepsis group (G7-NIS), (7-NI was applied 30 minutes before operation). Lipid
peroxidation index (LPI), nitrite concentration, superoxide dismutase (SOD)
activity and superoxide anion (O2·-) content were determined 3, 6, 24 and 48 hour in each
group. Cerebral capillaries were separated from non-vascular brain tissue
using sucrose gradient. Compared to controls, LPI, nitrite and O2·- increased at SG. In the G7-NIS, LPI reached control
values at the 24 th and 48 th hour, while nitrite were
decreased at the 3 rd and 24 th hour, compared to controls. In the same
group, O2·- decreased at the 3 rd, 6 th and 24 th hour, although SOD showed variable activity.
The systematic nNOS inhibition with 7-NI forces OS on early terms of sepsis,
but lately it contributes to the normalization of OS in cerebral capillaries.
Authors:M Slavić, M Slavić, M Slavić, I Appiah, I Appiah, I Appiah, A Nikolić-Kokić, A Nikolić-Kokić, A Nikolić-Kokić, R Radojičić, R Radojičić, R Radojičić, DR Jones, DR Jones, DR Jones, MB Spasić, MB Spasić, MB Spasić, S Milovanović, S Milovanović, S Milovanović, D Blagojević, D Blagojević, and D Blagojević
interactions between nitric oxide donors, reactive oxygen species and
anti-oxidative defence enzymes led us to determine the activities of
anti-oxidative defence enzymes in isolated uterine smooth muscle before and
after spontaneous rhythmic activity ex vivo. For our experiments we
used isolated uteri from female Wistar rats. Our results showed an increase
in total superoxide dismutase (SOD) and Mn SOD activities in uterine smooth
muscle after spontaneous contractions when compared with non-exercised
uterine smooth muscle. The activity of catalase (CAT) and glutathione
preoxidase (GSH-Px) were also increased. No statistically significant changes
in the activities of glutathione reductase (GR) and CuZn SOD were found. It
is known that an organism's anti-oxidative defence system (guarding against
excessive reactive oxygen species generation) requires balanced increments in
its individual anti-oxidative enzyme activities rather than increases in the
activity of only some enzymes without increases in others. Thus, we may
conclude that some adaptive responses are found in exercised uterine smooth
muscle but are not complete. Therefore, our results indicate that changes in
anti-oxidative enzyme activities may influence the results of the examination
of substances ex vivo.