The effects of sex and season on the metal levels and proximate composition of red mullet (Mullus barbatus Linnaeus 1758) caught from the Middle Black Sea

The effects of seasonal and sexual differences on the levels of macro, trace element, and toxic metal levels in Mullus barbatus were investigated using the ICP-MS. The quantity relationships of macro elements were found as K>P>Na>Ca>Mg for male, P>K>Na>Ca>Mg in female; the quantity relationships of trace elements were determined as Fe>Zn>Mn>Mo>Se>Cu>Ni>Co in male, Fe>Zn>Mn>Se>Cu>Ni>Mo>Co in female; and the quantity relationship of toxic elements were found as As>Pb>Cd in both male and female. Macro, trace, and toxic metal levels showed no significant differences (p > .05) in terms of sexuality, but demonstrated seasonal differences (p > .05). Overall, the highest level of macro elements was determined in the autumn, while the high level of trace elements was measured in the winter. The As, Cd, and Pb levels in the muscle tissue of red mullet fish were higher than acceptable limits. However, when the Estimated Daily Intake (EDI) and Estimated Weekly Intake (EWI) of both toxic metals are considered, they appear to be below acceptable limits. As a result, it was determined that the red mullet had been contaminated with toxic metals (Cd and Pb) but their levels according to EDI and EWI were below the limit.     

Electrophysiological and neuropsychological outcomes of severe obstructive sleep apnea: effects of hypoxemia on cognitive performance

Obstructive sleep apnea syndrome (OSAS) is a sleep disorder characterized with upper airway obstructions. Some studies showed cognitive and electrophysiological changes in patients with OSAS; however, contradictory results were also reported. The purpose of the present study was twofold: (1) to investigate cognitive changes in severe OSAS patients by using neuropsychological tests and electrophysiological methods together, (2) to investigate influence of hypoxemia levels on cognition. Fifty-four severe OSAS patients and 34 age-, gender- and education matched healthy subjects were participated. OSAS patients were further divided into two subgroups according to minimum oxygen saturation levels. All participants underwent a detailed neuropsychological test battery. A classical visual oddball task was used to elicit ERP P300 and mean P300 amplitudes were measured from F_z, C_z and P_z electrode sites. OSAS patients showed reduced mean P300 amplitudes up to 43–51% on all electrode sites compared to healthy controls. Subgroup analysis revealed significant differences in neuropsychological test scores between healthy controls and high hypoxemia OSAS group, as well as between low and high hypoxemia groups. Moreover, both low and high hypoxemia OSAS groups had lower P300 amplitudes compared with healthy controls. P300 amplitudes showed a gradual decline in parallel with increasing hypoxemia severity; however, the difference between high and low hypoxemia OSAS groups did not reach significance. Moderate correlations were found between sleep parameters, neuropsychological test scores and P300 amplitudes. These results suggest that electrophysiological measures could be better indicators of cognitive changes than neuropsychological tests in OSAS, particularly in mildly affected patients.     

Experimental design methods for bioengineering applications

Experimental design is a form of process analysis in which certain factors are selected to obtain the desired responses of interest. It may also be used for the determination of the effects of various independent factors on a dependent factor. The bioengineering discipline includes many different areas of scientific interest, and each study area is affected and governed by many different factors. Briefly analyzing the important factors and selecting an experimental design for optimization are very effective tools for the design of any bioprocess under question. This review summarizes experimental design methods that can be used to investigate various factors relating to bioengineering processes. The experimental methods generally used in bioengineering are as follows: full factorial design, fractional factorial design, Plackett–Burman design, Taguchi design, Box–Behnken design and central composite design. These design methods are briefly introduced, and then the application of these design methods to study different bioengineering processes is analyzed.     

Efflux of Glutathione and Glutathione Complexes from Human Erythrocytes in Response to Inorganic Arsenic Exposure

The objective of the present study was to investigate if arsenic exposure results in glutathione efflux from human erythrocytes. Arsenite significantly depleted intracellular nonprotein thiol level in a time- and concentration-dependent manner. The intracellular nonprotein thiol level was decreased to 0.767?±?0.0017???mol/ml erythrocyte following exposure to 10?mM of arsenite for 4?h. Extracellular nonprotein thiol level was increased concomitantly with the intracellular decrease and reached to 0.481?±?0.0005???mol/ml erythrocyte in 4?h. In parallel with the change in extracellular nonprotein thiol levels, significant increases in extracellular glutathione levels were detected. Extracellular glutathione levels reached to 0.122?±?0.0013, 0.226?±?0.003, and 0.274?±?0.004???mol/ml erythrocyte with 1, 5, and 10?mM of arsenite, respectively. Dimercaptosuccinic acid treatment of supernatants significantly increased the glutathione levels measured in the extracellular media. Utilization of MK571 and verapamil, multidrug resistance-associated protein 1 and Pgp inhibitors, decreased the rate of glutathione efflux from erythrocytes suggesting a role for these membrane transporters in the process. The results of the present study indicate that human erythrocytes efflux glutathione in reduced free form and in conjugated form or forms that can be recovered with dimercaptosuccinic acid when exposed to arsenite.     

Expression of p97/VCP and ubiquitin during postnatal development of the degenerating rat retina

In this study, we aimed to investigate the distribution pattern of ubiquitin and p97/VCP in the rat retina during postnatal development. Eyeballs from 1-, 4-, 10-, 36- and 72-week-old rats were examined by immunohistochemistry, and protein colocalization was determined by immunofluorescence microscopy. In the 1-week-old rat retina, p97/VCP was strongly expressed in the neuroblast layer, however no ubiquitin immunoreactivity was observed. p97/VCP immunoreactivity was present in the ganglion cell layer (GCL), inner nuclear layer (INL), outer nuclear layer (ONL), inner segment (IS) of the photoreceptor layer, and retinal pigment epithelium in the 4- and 10-week-old rat retinas. p97/VCP immunoreactivity increased significantly in the 10-week-old rat retinas. Ubiquitin was barely seen in the 4-week-old rat retinas, and ubiquitin expression was weak in the GCL and the IPL of the 10-week-old rat retinas. In the 36- and 72-week-old rats, the presence of ubiquitin was remarkable in the IS, INL, IPL and GCL, however, p97/VCP immunoreactivity was significantly decreased. Colocalization of ubiquitin and p97/VCP was also observed in the INL, IS, GCL and ONL of 36- and 72-week-old rat retinas. Our results indicate that p97/VCP immunoreactivity in the retina significantly decreases after rats reach 10 weeks of age, whereas ubiquitin immunoreactivity increases with aging. These results suggest that an altered expression pattern of p97/VCP and ubiquitin in the developing rat retina may associate with age-related retinal degeneration.     

Molecular epidemiology of penicillin resistantStreptococcus pneumoniae strains in Turkey. A multicenter study

A total of 539 isolates recovered from various clinical sites were collected from 13 hospitals from different regions of Turkey between 1999 and 2002. Susceptibility to penicillin and cefotaxime was determined by the E-test and the remaining antimicrobials were evaluated by disk diffusion tests. Penicillin resistant and intermediate isolates were serotyped and PFGE patterns were analysed. Overall 16 isolates (3%) were resistant to penicillin, and 143 (26.5%) were intermediate. Resistance and intermediate rates were 3.1% and 29.0% respectively in respiratory tract isolates. Multiple resistance (resistance to ≥3 antibiotics) occurred in 81.8% of the penicillin resistant isolates and the most frequent resistance phenotype was penicillin+trimethoprim/sulphamethoxazole (37.7%). Minimum inhibitory concentrations of cefotaxime were lower than 1 mg/ml for all the isolates. The highest rate of resistance was observed for trimethoprim/ sulphamethoxazole (26.6%) followed by doxycycline (12.6%). Resistance to erythromycin was 10.1%, clindamycin 9.9%, chloramphenicol 4.3%, ofloxacin 5.0% and levofloxacin 0.2%. There was no resistance to vancomycin. Resistant isolates belonged to serogroups 9, 23, and 6. The most frequent serogroups among intermediate isolates were 23, 19, 14, 1, 9, and 6. Five distinct PFGE patterns were observed among penicillin resistant isolates. There was no distinct clustering of specific PFGE patterns in the study centres. No correlation between serotypes, resistance and PFGE patterns was found. There seems to be genetic heterogeneity inStreptococccus pneumoniae isolates in Turkey.