Serhan Sakarya

Nitric oxide regulates bacterial translocation in experimental acute edematous pancreatitis

Background/Aims: The role of nitric oxide (NO) in bacterial translocation (BT) associated with acute pancreatitis is controversial. We investigated the effects of the NO synthase substrate, L-arginine, and the NO synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME), on BT in caerulein-induced acute pancreatitis in rats. Methods: Acute pancreatitis was induced by subcutaneous injections of caerulein (12 µg/kg) at 6-hour intervals for 2 days. Subcutaneous injections of L-arginine (100 mg/kg) or L-NAME (10 mg/kg) were administeredonce daily for 2 days. At 48 h, pancreatic injury and BT to the mesenteric lymph nodes (MLN), liver, and peritoneum were assessed. Results: Compared with controls, rats that received caerulein injections alone had increased BT to the MLN and pancreatic inflammatory changes. L-Arginine significantly reduced the inflammation and BT caused by caerulein. L-NAME did not significantly alter pancreatic inflammation. Although caerulein + L-NAME-treated rats had increased BT to the peritoneum, MLN, and liver compared with controls, rates of BT did not significantly differ between caerulein alone- and caerulein + L-NAME-treated rats. Conclusion: In acute edematous pancreatitis, BT is increased and is regulated by NO. NO substrates limit BT and pancreatic inflammation associated with acute pancreatitis, probably by their bactericidal actions and ability to improve pancreatic blood flow.

The synthesis and targeting of PPP-type copolymers to breast cancer cells: Multifunctional platforms for imaging and diagnosis

Herein, we demonstrate the synthesis and application of water-soluble, biomolecule conjugated PPP copolymers bearing poly(ethylene glycol) (PEG) side chains as fluorescent probes for the in vitro imaging of cancer cells. The targeting of fluorescent polymers to breast cancer cells allows effective visualization and discrimination of MCF7 cells from human mammary epithelial cells. Furthermore, these materials are also suitable for efficient radiolabeling via125I which enables dual-modality holding the possibility of both radioactive and fluorescence imaging in cancer diagnosis applications.

Sialic acid is required for nonspecific adherence of Salmonella enterica ssp. enterica serovar Typhi on Caco-2 cells

To initiate infection, bacteria must adhere to and colonize host tissues. Specific and nonspecific mechanisms participate in the adherence process. Salmonella enterica ssp. enterica serovar Typhi (S. Typhi) must first adhere to the intestinal epithelium to invade and disseminate throughout the host. In this study, the role of colonic epithelial cell surface sialic acid in the adherence of S. Typhi was defined. Neuraminidase treatment of colonic Caco-2 cells removed 27-58% of surface sialic acid. Thus desialylation diminished the adherence of S. Typhi by 41%. Sialic acid treatment of S. Typhi had no effect on their adherence to neuraminidase-treated or control cells. These results indicate that sialic acid on the surface of colonic cells enhances S. Typhi adherence. These findings may suggest novel therapeutic strategies for S. Typhi infections.

Saccharomyces boulardii expresses neuraminidase activity selective for α2,3‐linked sialic acid that decreases Helicobacter pylori adhesion to host cells

Helicobacter pylori is a major causative agent of gastritis and peptic ulcer disease and is an established risk factor for gastric malignancy. Antibiotic combination therapy can eradicate H. pylori. As these same regimens can evoke adverse effects and resistance, new alternative therapies or adjunctive treatments are needed. A probiotic approach may provide a novel strategy for H. pylori treatment. In the current study, two probiotic bacteria, Lactobacillus acidophilus and Lactobacillus reuteri, and a probiotic yeast, Saccharomyces boulardii, were evaluated for their ability to influence H. pylori viability, adherence to gastric and duodenal cells, as well as the effect of S. boulardii on cell surface expression of sialic acid. Our results indicate that S. boulardii contains neuraminidase activity selective for α(2‐3)‐linked sialic acid. This neuraminidase activity removes surface α(2‐3)‐linked sialic acid, the ligand for the sialic acid‐binding H. pylori adhesin, which in turn, inhibits H. pylori adherence to duodenal epithelial cells.

The seroprevalence of Crimean-Congo haemorrhagic fever among inhabitants living in the endemic regions of Western Anatolia

Abstract Background: In Turkey, Crimean-Congo haemorrhagic fever (CCHF) is seen particularly in the north-eastern part of Anatolia. Aydin was thought to be a non-endemic area, however the first case was reported from Aydin in 2006 and a total of 39 cases were reported between 2006 and 2010. Methods: Four hundred and twenty-nine volunteers from 3 endemic regions of Aydin were enrolled in this study. We determined the IgG seropositivity against the virus by enzyme-linked immunosorbent assay (ELISA) method. Results: IgG seropositivity in the study group was found to be 19.6% (n = 84). Chi-squared automatic interaction detector (CHAID) analysis was performed and a significant relationship between IgG seropositivity and tick-bite was found. The IgG seropositivity rate was 13% in cases without a history of tick-bite, while it was 41.1% in those with a tick-bite history (p < 0.001). In cases without a history of tick-bite (n = 339), the most important factor related to seropositivity was cattle-dealing. The seropositivity rate was higher in women than in men in the group dealing with cattle without a history of tick-bite (p = 0.013). In cases with a tick-bite history, the most important factor related to IgG seropositivity was age; the rate was 81% in cases younger than 34 y old, while it was 29% in cases older than 34 y. Conclusions: This study indicates that people suffering from the disease did not ask for any professional healthcare or that the healthcare providers could not diagnose these cases.

Polysulfone/Pyrene Membranes: A New Microwell Assay Platform for Bioapplications

The use of PSU-Py prepared by click chemistry as a platform in membrane-bottom microwell plates for oxidase and hydrolase/oxidase-based enzyme assays is studied. For the GOx assay, the postulated fluorescence mechanism is based on the consumption of glucose by dissolved oxygen and GOx in the microwell plates covered with the PSU-Py membrane. For the AG-GOx assay, maltose is used as AG substrate and hydrolyzed to glucose which is then oxidized by the GOx activity. It is shown that the PSU-Py membrane acts as a fluorescence indicator of the enzymatic reactions, and both GOx and AG/GOx enzyme assays are successfully applied for glucose, maltose and acorbose analysis in the range 0.125-2.0 × 10(-3) M glucose, 0.05-0.5 × 10(-3) M maltose, and 0.0125-0.1 mg · mL(-1) acorbose, respectively.

Escherichia coli bind to urinary bladder epithelium through nonspecific sialic acid mediated adherence

The first step in the bacterial colonization and infection of uropathogenic Escherichia coli is adherence to uroepithelium. Over 80% of all urinary tract infections are caused by E. coli. Uropathogenic E. coli express several adherence factors including type 1 and P fimbriae, which mediate attachment to the uroepithelium through specific binding to different glycoconjugate receptors. We showed that P and type 1 fimbriae are not the sole adhesins on uropathogenic E. coli and sialic acid also mediates nonspecific bacterial adherence of uropathogenic E. coli and urinary bladder epithelium.

Enzymatic Synthesis of Uracil Glucuronide, Labeling with 125/131I, and In Vitro Evaluation on Adenocarcinoma Cells

Human UDP-glucuronosyltransferases (UGTs) are a family of membrane-bound enzymes of the endoplasmic reticulum. They catalyze the glucuronidation of various endogenous and exogenous compounds, converting them into more polar glucuronides. In this study, uracil glucuronide was enzymatically synthesized using a UGT-rich microsome preparate, which was separated from Hutu-80 cells. Two different glucuronide derivatives were obtained, with a total reaction yield of 22.95% +/- 2.4% (n = 4). The glucuronide ligands were defined as uracil-n-glucuronide (UNG) and uracil-o-glucuronide (UOG). These were then analyzed by high-performance liquid chromatography-mass spectrometry and labeled with I-125 and I-131, separately. The radiolabeled (125/131)I-UNG and (125/131)I-UOG presented good incorporation ratios for Hutu-80, Caco-2, Detroit 562, and ACBRI 519 cells. The incorporation ratios of (125/131)I-UOG were higher than those of (125/131)I-UNG and of other labeled components for all cell types, and were also statistically significant compared to the values of (125/131)I-UNG for primary human intestinal epithelial cells (ACBRI 519) and human intestinal adenocarcinoma cells. Cell incorporation rates of n-glucuronides and o-glucuronides were higher compared to uracil, with o-glucuronides being more selective. The results suggest that both I-125- and I-131-labeled glucuronides can be used in imaging and therapy, and further research should be done in preclinical stages.

Photochemically prepared polysulfone/poly(ethylene glycol) amphiphilic networks and their biomolecule adsorption properties.

Polysulfone/poly(ethylene glycol) amphiphilic networks were prepared via in situ photo-induced free radical crosslinking polymerization. First, the hydrophobic polysulfone diacrylate (PSU-DA) oligomer was synthesized by condensation polymerization and subsequent esterification processes. Then, the obtained oligomer was co-crosslinked with the hydrophilic poly(ethylene glycol) diacrylate (PEG-DA) or poly(ethylene glycol) methyl ether acrylate (PEG-MA) at different feed ratios. In the case of PEG-MA, the resulting network possessed dangling pendant hydrophilic chains on the crosslinked surface. The structure and the morphology of the membranes were characterized by attenuated total reflection infrared spectroscopy (ATR-IR) and scanning electron microscopy (SEM). The enhancement of surface hydrophilicity was investigated by water contact angle measurements. The biomolecule adsorption properties of these networks were also studied. The biomolecules easily adsorbed on the surface of the hydrophobic polysulfone networks whereas dangling hydrophilic chains on the surface prevented the adsorption of the biomolecules.

Investigation of Therapeutic Efficiency of Bleomycin and Bleomycin-Glucuronide Labeled with 131I on the Cancer Cell Lines

The aim of this study is to determine the incorporations of radiolabeled bleomycin ((131)I-BLM) and bleomycin-glucuronide ((131)I-BLMGLU) on PC-3 (human prostate carcinoma cell line), Caco-2 (human colon adenocarcinoma cell line), Hutu-80 (Human Duodenum adenocarcinoma cell line), and A549 (Human lung adenocarcinoma epithelial cell line) cancerous cell lines. For this purpose, BLM and BLMGLU enyzmatically synthesized were labeled with (131)I, quality control studies were done and the incorporation yields of (131)I-BLM and (131)I-BLMGLU on these cell lines were measured. Quality-control studies showed that the radiolabeling yields were obtained as 95% and 90% for (131)I-BLM and (131)I-BLMGLU, respectively. Also, as a result of the cell culture studies, it was found that (131)I-BLM and (131)I-BLMGLU had higher incorporation on PC-3 cells than that of other cell lines. In addition to this, it was reported that the incorporation yield of (131)I-BLMGLU was higher than that (131)I-BLM. At the end of the study, cytotoxicities of BLM and BLMGLU on PC-3 cancerous cell line were inspected and fluorescent images of BLM and BLMGLU were taken on PC-3 cells by using fluorescein isothiocyanate. In conclusion, cell culture studies demonstrated that the incorporation values of (131)I-BLMGLU on the four cell lines were about five to six times higher than (131)I-BLM. Radiolabeled glucuronide derivatives can be used in cancer therapy and tumor imaging, depending on the properties of radioiodine for the β-glucuronidase-rich tissues because glucuronidation leads to rapid and higher incorporation on adenocarcinoma cells.