Effect of alpha-lipoic acid supplementation on markers of protein oxidation in post-mitotic tissues of ageing rat

In the present study, we investigated whether DL-alpha-lipoic acid (LA) supplementation could have prooxidant or antioxidant effects on oxidative protein damage parameters such as protein carbonyl (PCO), nitrotyrosine (NT), advanced oxidation protein products (AOPP), and protein thiol (P-SH), as well as oxidative stress parameters such as total thiol (T-SH), non-protein thiol (Np-SH), and lipid hydroperoxide (LHP) in the brain and the skeletal muscle tissue of aged rats. PCO, and NT levels were increased, AOPP and P-SH levels were not changed in the brain tissue of aged rats given LA supplementation. On the other hand, TSH, Np-SH, and LHP levels were decreased in the brain tissue of aged rats given LA supplementation. The levels of the same parameters were not significantly different in the skeletal muscle tissue of aged rats given LA supplementation. The increased levels of protein oxidation markers such as PCO, and NT in the brain tissue of LA-supplemented aged rats compared with non-supplemented aged rats may suggest that oxidative protein damage is increased in LA-supplemented aged rats. We assume that an explanation for our findings regarding LA supplementation on protein oxidation markers in the brain tissue of aged rats may be due to the prooxidant effects of LA. Depending on post-mitotic tissue type and dosage of LA, the prooxidant effects of LA supplementation, should be considered in future studies.     

Glatiramer Acetate Increases Phagocytic Activity of Human Monocytes In Vitro and in Multiple Sclerosis Patients

Beside its effects on T cells, a direct influence on cells of the myelo-monocytic lineage by GA becomes evident. Recently, we demonstrated that GA drives microglia to adopt properties of type II antigen presenting cells (APC) and increases their phagocytic activity. In the present work, we focused on human blood monocytes in order to examine whether GA may increase phagocytic activity in vivo and to evaluate the molecular mechanisms explaining this new discovered mode of action. Peripheral blood mononuclear cells (PBMC) were obtained using a Biocoll-Isopaque gradient and monocytes were subsequently isolated by using CD14 MicroBeads. Phagocytic activity was determined by flow cytometric measurement of the ingestion of fluorescent beads. Flow cytometry was also used to assess monocytic differentiation and expression of phagocytic receptors. Monocytes of GA treated MS patients exhibited a significantly higher phagocytic activity than those of healthy controls or non-treated MS patients. In vitro, a significant phagocytic response was already detectable after 1 h of GA treatment at the concentrations of 62.5 and 125 µg/ml. A significant increase at all concentrations of GA was observed after 3 h and 24 h, respectively. Only monocytes co-expressing CD16, particularly CD14⁺⁺CD16⁺ cells, were observed to phagocytose. Treatment of monocytes with IL-10 and supernatants from GA-treated monocytes did not alter phagocytosis. We observed a decrease in CD11c expression by GA while no changes were found in the expression of CD11b, CD36, CD51/61, CD91, TIM-3, and CD206. In our blocking assays, treatment with anti-CD14, anti-CD16, anti-TIM3, anti-CD210, and particularly anti-CD36 antibodies led to a decrease in phagocytosis. Our results demonstrate a new mechanism of action of GA treatment that augments phagocytic activity of human monocytes in vivo and in vitro. This activity seems to arise from the CD14⁺⁺CD16⁺ monocyte subset.     

Serum and hair zinc levels in epileptic children taking valproic acid

This study was performed to investigate the serum and hair zinc levels in patients having epilepsy diagnoses who were intended to be put on valproic acid (VA) monotherapy and had never ingested antiepileptics before. A total of 16 patients having normal growth, development, and nutrition was selected as Group 1, and Group 2 was made up of 10 patients who had received VA monotherapy for 2 yrs or more and had normal growth, development, and nutrition characteristics. A control group (Group 3) was formed of 15 subjects who applied to the hospital for upper respiratory tract disorders. Serum and hair samples were taken for zinc assays from the Group 1 patients on the d 0, 15, 30, 45, 60, 75, and 180. Groups 2 and 3 were sampled only once, and zinc levels were determined. We found that both serum and hair zinc levels in Group 1 were higher than those of Group 2 and control group before the beginning of VA therapy, but they returned to normal during VA treatment. There was no zinc deficiency, and zinc replacement treatment may therefore be considered as unnecessary.     

Changes in the rates of antimicrobial resistance among clinical isolates of Pseudomonas aeruginosa between 2002 and 2004 in a tertiary-care teaching hospital in Turkey

Pseudomonas aeruginosa is an important opportunistic pathogen usually resistant to most antimicrobials. We present changes in the resistance pattern of P. aeruginosa to amikacin (AK) and ciprofloxacin (CIP) between January 2002 and June 2004. The physicians of each unit were given information on antibiotic resistance rates of P. aeruginosa isolated from ward patients at regular intervals. The antibiotic resistance of 161 P. aeruginosa isolates isolated from intensive care units (ICUs) and non-ICUs were tested by disk diffusion method, and the results were interpreted according to the guidelines of National Committee for Clinical Laboratory Standards. Thirty-five percent of all the P. aeruginosa isolates were resistant to AK in 2002, 18% in 2003, and 20% in 2004. The CIP resistance rates were 4% in 2002, 26% in 2003, and 20% in 2004. In that period, resistance to AK decreased, whereas resistance to CIP increased. The usage rate of AK in 2002 was 32%, which fell to 26% in 2003 (p < 0.05). This rate increased to 27% in 2004 (p < 0.05). The usage rate of CIP was very low in 2002 (3%). Subsequently, it increased to 8% in 2003 and 2004 (p < 0.05). The changes in resistance rates may have been due to alteration in drug usage policy in our hospital. It is important to provide physicians with information on antibiotic resistance rates at regular intervals to guide therapy for critical P. aeruginosa infections.     

Serum and gastric fluid levels of cytokines and nitrates in gastric diseases infected with Helicobacter pylori

This case control study presents data on the concentrations of nitrite and nitrate and a variety of pro-inflammatory cytokines such as interleukin-1 beta (IL-1 beta), interleukin-2R (IL-2R), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor TNF-alpha in gastric fluid and serum. Patients with gastritis, gastric ulcer and gastric cancer are studied and grouped according to infection by Helicobacter pylori. The 208 patients who underwent upper gastrointestinal endoscopic examination were classified as follows; H. pylori-positive gastritis (n = 32), H. pylori-negative gastritis (n = 32), H. pylori-positive ulcers (n = 34), H. pylori-negative ulcers (n = 34), 43 patients with H. pylori-positive gastric cancer in addition to 33 H. pylori-negative healthy control individuals. Gastric fluids and blood samples were taken concomitantly. Cytokines and nitrite and nitrate determinations were attempted as soon as possible after collection of the samples. Nitrite and nitrate levels of serum and gastric fluids of H. pylori-positive gastritis and ulcers were higher than H. pylori-negative gastritis and ulcers. The concentrations of total nitrite and nitrate and cytokines (TNF-alpha, IL-2R, IL-6, and IL-8) in gastric fluids and sera of H. pylori-positive gastric cancer patients were higher than H. pylori-negative control groups. IL-1 beta level was significantly elevated in gastric fluid of infected cancer patients but not in serum. Taken together, the results suggest that an increase in cytokine-NO combination in gastric mucosa previously reported by many studies is not restricted to local infected gastric tissue but also detected in gastric fluid and sera of H. pylori-positive subjects and may have an important role in the pathogenesis and development of common gastric diseases.     

Extremely Low-Frequency Magnetic Field Decreased Calcium,Zinc and Magnesium Levels in Costa of Rat

Electromagnetic field (EMF) can affect cells due to biochemical change followed by a change in level of ions trafficking through membrane. We aimed to investigate possible changes in some elements in costa of rats exposed to long-term extremely low-frequency magnetic field (ELF-MF). Rats were exposed to 100 and 500 μT ELF-MF, which are the safety standards of public and occupational exposure for 2 h/day during 10 months. At the end of the exposure period, the samples of costa were taken from the rats exposed to ELF-MF and sham. The levels of elements were measured by using atomic absorption spectrophotometry (AAS) and ultraviolet (UV) spectrophotometry. Ca levels decreased in the ELF-500 exposure group in comparison to sham group (p < 0.05). Statistically significant decrease was found in Mg levels in the ELF-500 exposure group in comparison to sham and ELF-100 exposure groups (p < 0.05). Zn levels were found to be lower in the ELF-500 exposure group than those in the sham and ELF-100 exposure groups (p < 0.05). No significant differences were determined between groups in terms of the levels of P, Cu and Fe. In conclusion, it can be maintained that long-term ELF-MF exposure can affect the chemical structure and metabolism of bone by changing the levels of some important elements such as Ca, Zn and Mg in rats.     

Comprehensive profiling of radiosensitive human cell lines with DNA damage response assays identifies the neutral comet assay as a potential surrogate for clonogenic survival

In an effort to explore the possible causes of human radiosensitivity and identify more rapid assays for cellular radiosensitivity, we interrogated a set of assays that evaluate cellular functions involved in recognition and repair of DNA double-strand breaks: (1) neutral comet assay, (2) radiation-induced γ-H2AX focus formation, (3) the temporal kinetics of structural maintenance of chromosomes 1 phosphorylation, (4) intra-S-phase checkpoint integrity, and (5) mitochondrial respiration. We characterized a unique panel of 19 "radiosensitive" human lymphoblastoid cell lines from individuals with undiagnosed diseases suggestive of a DNA repair disorder. Radiosensitivity was defined by reduced cellular survival using a clonogenic survival assay. Each assay identified cell lines with defects in DNA damage response functions. The highest concordance rate observed, 89% (17/19), was between an abnormal neutral comet assay and reduced survival by the colony survival assay. Our data also suggested that the neutral comet assay would be a more rapid surrogate for analyzing DNA repair/processing disorders.     

A novel TMPRSS3 missense mutation in a DFNB8/10 family prevents proteolytic activation of the protein

Pathogenic mutations in TMPRSS3, which encodes a transmembrane serine protease, cause non-syndromic deafness DFNB8/10. Missense mutations map in the low density-lipoprotein receptor A (LDLRA), scavenger-receptor cysteine-rich (SRCR), and protease domains of the protein, indicating that all domains are important for its function. TMPRSS3 undergoes proteolytic cleavage and activates the ENaC sodium channel in a Xenopus oocyte model system. To assess the importance of this gene in non-syndromic childhood or congenital deafness in Turkey, we screened for mutations affected members of 25 unrelated Turkish families. The three families with the highest LOD score for linkage to chromosome 21q22.3 were shown to harbor P404L, R216L, or Q398X mutations, suggesting that mutations in TMPRSS3 are a considerable contributor to non-syndromic deafness in the Turkish population. The mutant TMPRSS3 harboring the novel R216L missense mutation within the predicted cleavage site of the protein fails to undergo proteolytic cleavage and is unable to activate ENaC, thus providing evidence that pre-cleavage of TMPRSS3 is mandatory for normal function.Marie Wattenhofer and Nilüfer Sahin-Calapoglu contributed equally to this work