Can the Reduction of Cytokines Stop the Progression of Sepsis?

Objective In this study, we aimed to analyze the laboratory and clinical results of cytokine hemadsorption as an immunomodulation therapy in ICU patients diagnosed with sepsis or septic shock. Methods The levels of procalcitonin (PCT) and C-reactive protein (CRP), determined to be indicators of infection/sepsis, and the levels of interleukins (IL-6, IL-8, and IL-10) and tumor necrosis factor α (TNFα), deemed as indicators of the cytokine storm, were compared among 32 patients before and after the hemadsorption procedure. Results The hemadsorption significantly reduced the levels of IL-6, IL-8, IL-10, TNFα, PCT, CRP, Acute Physiology and Chronic Health Evaluation (APACHE) scores, mortality rate, and Sequential Organ Failure Assessment (SOFA) scores (p<0.05). APACHE scores and the mean predicted mortality rate (PMR) of the non-survivors measured before the procedure was significantly higher than those of survivors (p=0.002 for both). IL-10, APACHE scores, and the mortality rates determined before the hemadsorption procedure were deemed significant parameters to predict the mortality among all ICU patients (p<0.05). IL-10 levels ≤125.3 ng/L, APACHE score >30, and PMR >70.33 were significantly associated with the mortality rates of all patients, indicating that these three parameters determined before the hemadsorption may be good predictors of mortality among ICU patients with sepsis. Conclusion The progression of sepsis in ICU patients may be prevented with cytokine hemadsorption applied as an immunomodulator therapy.

Complexes of glucose oxidase with chitosan and dextran possessing enhanced stability.

In this study, the different mole ratios of glucose oxidase/chitosan/dextran-aldehyde and glucose oxidase/chitosan/dextran-sulfate complexes were synthesized. The modification of glucose oxidase by non-covalent complexation with dextran and chitosan in different molar ratios was studied in order to increase the enzyme activity. The enzyme/polymer complexes obtained were investigated by UV spectrophotometer and dynamic light scattering. Activity determination of synthesized complexes and free enzyme were performed at a temperature range. The best results were obtained by Cchitosan/Cdextran-aldehyde = 10/1 ratio and Cchitosan/Cdextran-sulfate = 1/5 ratio that were used in thermal stability, shelf life, salt stress, and ethanol effect experiments. The results demonstrated that both complexes were thermally stable at 60 °C and had superior storage stability compared to the free glucose oxidase. Complexes showed higher enzymatic activity than free enzyme in the organic solvent environment using 10% ethanol. The complexes were resistant to salt stress containing 0.1 M NaCl or CaCl2. The particle size distribution results of the triple complex evaluated the complexation of the chitosan, dextran derivative, and glucose oxidase. The average size of the triple complex in diameter was found to be 325.8 ± 9.3 nm. Overall findings suggest that the complexes of glucose oxidase, chitosan, and dextran showed significant enhancement in the enzyme activity.

Development of urea biosensor using non-covalent complexes of urease with aldehyde derivative of PEG and analysis on serum samples.

Non-covalent complexes of urease/polyethylene glycol (PEG)-aldehyde were synthesized using regular molar ratios of urease and PEG-aldehyde at room temperature. The physical properties of the non-covalent complexes were analyzed in order to investigate the impact of coupling ratio, temperature, pH, storage stability, and thermal stability. Urease activity was analyzed by UV-Vis spectrophotometer at 630 nm. The results showed that the strongest thermal resistance was obtained using nU/nPEG:1/1 (mg/mL) complex within all molar ratios tested. The enzymatic activity of nU/nPEG:1/1 complex doubled the activity of the free enzyme. Therefore, this complex was chosen to be used in the analyses. When coupled with PEG-aldehyde, urease exhibited improved activity between pH 4.0-9.0 and the optimum pH was found to be 7.0. The thermal inactivation results of the complex demonstrated that higher activity remained (40%) when compared with the free enzyme (10%) at 60 °C. The storage stability of the non-covalent complex was 4 weeks which was greater than the storage stability of the free enzyme. A kinetic model was suggested in order to reveal the mechanism of enzymatic conversion. Potentiometric urea biosensor was prepared using two different membranes: carboxylated poly vinyl chloride (PVC) and palmitic acid containing PVC. The potentiometric responses of both sensors were tested against pH and temperature and the best results were obtained at pH 7.0 and 20-30 °C. Also, selectivity of the suggested biosensors toward Na+, Li+ Ca2+, and K+ ions was evaluated and the reproducibility responses of the urea biosensors were measured with acceptable results.

Synthesis of glucose oxidase-PEG aldehyde conjugates and improvement of enzymatic stability.

In this article, aldehyde derivative of poly(ethylene glycol) (PEG) was synthesized directly with sodium periodate agent. To obtain a conjugate which possesses better stability, PEG aldehyde was bonded to native enzyme with different molar ratios. The conjugation reaction turned out to be efficient and mild. Colorimetric method was applied to evaluate the enzymatic activity of native GOD and its derivatives by introducing another enzyme, horseradish peroxidase. The GOD-PEG aldehyde conjugate with polymeric chains exhibited reduced enzymatic activity towards the catalytical oxidation of glucose, but with significantly increased thermal stability and elongated lifetime. When GOD was modified with PEG aldehyde the enzymatic activity was decreased 40% at 30 °C. However, when incubated at 60 °C the GOD-PEG aldehyde conjugate still retained the enzyme bioactivity of 40% bioactivity left after 4 h, whereas the native GOD lost almost all the activity in 4 h. The polymer chain attached, the more reduction of the enzymatic activity resulted, however, the longer the lifetime and higher thermal stability of the enzyme obtained.

Measuring calcium, potassium, and nitrate in plant nutrient solutions using ion-selective electrodes in hydroponic greenhouse of some vegetables.

Generally, the life cycle of plants depends on the uptake of essential nutrients in a balanced manner and on toxic elements being under a certain concentration. Lack of control of nutrient levels in nutrient solution can result in reduced plant growth and undesired conditions such as blossom-end rot. In this study, sensitivity and selectivity tests for various polyvinylchloride (PVC)-based ion-selective membranes were conducted to identify those suitable for measuring typical concentration ranges of macronutrients, that is, NO(3-), K(+), and Ca(2+), in hydroponic solutions. The sensitivity and selectivity of PVC-membrane-based ion-selective sensors prepared with tetradodecylammoniumnitrate for NO(3-), valinomycin for K(+), and Ca ionophore IV for Ca(2+) were found to be satisfactory for measuring NO(3-), K(+), and Ca(2+) ions in nutrient solutions over typical ranges of hydroponic concentrations. Potassium, calcium, and nitrate levels that were utilized by cucumber and tomato seedlings in the greenhouse were different. The findings show that tomato plants consumed less amounts of nitrate than cucumber plants over the first 2 months of their growth. We also found that the potassium intake was higher than other nutritional elements tested for all plants.