Controlled oxidation of calf thymus DNA to produce standard samples for 8-Oxodeoxyguanosine analysis; Effects of freeze-drying,storage and hydrolysis conditions

Calf thymus DNA containing defined levels of 8-hydroxy-2′-deoxyguanosine (8-oxodG) was prepared by treatment with visible light in the presence of photosensitiser Ro 19-8022. The DNA was checked for stability; after freeze-drying, the amount of 8-oxodG did not increase during 6 weeks' storage at room temperature. However, freeze-drying itself can introduce additional oxidative damage. Two enzymic hydrolysis regimes (DNase I, phosphodiesterases I and II, and alkaline phosphatase; or P1 nuclease and alkaline phosphatase) give similar values for 8-oxodG.     

Direct and Indirect Control of the Initiation of Meiotic Recombination by DNA Damage Checkpoint Mechanisms in Budding Yeast

Meiotic recombination plays an essential role in the proper segregation of chromosomes at meiosis I in many sexually reproducing organisms. Meiotic recombination is initiated by the scheduled formation of genome-wide DNA double-strand breaks (DSBs). The timing of DSB formation is strictly controlled because unscheduled DSB formation is detrimental to genome integrity. Here, we investigated the role of DNA damage checkpoint mechanisms in the control of meiotic DSB formation using budding yeast. By using recombination defective mutants in which meiotic DSBs are not repaired, the effect of DNA damage checkpoint mutations on DSB formation was evaluated. The Tel1 (ATM) pathway mainly responds to unresected DSB ends, thus the sae2 mutant background in which DSB ends remain intact was employed. On the other hand, the Mec1 (ATR) pathway is primarily used when DSB ends are resected, thus the rad51 dmc1 double mutant background was employed in which highly resected DSBs accumulate. In order to separate the effect caused by unscheduled cell cycle progression, which is often associated with DNA damage checkpoint defects, we also employed the ndt80 mutation which permanently arrests the meiotic cell cycle at prophase I. In the absence of Tel1, DSB formation was reduced in larger chromosomes (IV, VII, II and XI) whereas no significant reduction was found in smaller chromosomes (III and VI). On the other hand, the absence of Rad17 (a critical component of the ATR pathway) lead to an increase in DSB formation (chromosomes VII and II were tested). We propose that, within prophase I, the Tel1 pathway facilitates DSB formation, especially in bigger chromosomes, while the Mec1 pathway negatively regulates DSB formation. We also identified prophase I exit, which is under the control of the DNA damage checkpoint machinery, to be a critical event associated with down-regulating meiotic DSB formation.     

Basal metabolic rate and autonomic nervous system dysfunction in men with spinal cord injury

Objectives: The purpose of this study was to determine the relationship between autonomic nervous system dysfunction and basal metabolic rate (BMR), and the effect of spasticity on basal metabolic rate. Research Method and Procedures: Twenty men (11 paraplegic and 9 tetraplegic) with American Spinal Injury Association (ASIA)‐A and ‐B grade chronic spinal cord injury (SCI) participated in this study. Total body fat mass and lean tissue mass were measured in all participants using DXA by standard methods. Patients were allocated into 2 groups to determine the effect of autonomic nervous system dysfunction on BMR: Group I (T6 and upper‐level injuries with history of autonomic dysreflexia) and Group II (T7 and lower‐level injuries without history of autonomic dysreflexia). Measurements of BMR were determined by indirect calorimetry under standardized conditions. Results: There were 13 patients in Group I and 7 patients in Group II and the difference between these two in terms of time since injury, BMI, age, weight, lean tissue mass, BMR, and BMR/kg were not significant. Conclusion: We concluded that autonomic nervous system dysfunction does not affect BMR, and it might be ignored in considering energy needs in spinal cord injury.     

Antioxidant and antimicrobial actions of the clubmoss <Emphasis Type="Italic">Lycopodium clavatum</Emphasis> L.

Purpose of the present study was to evaluate antioxidant, antibacterial, antifungal, and antiviral activities of the petroleum ether, chloroform, ethyl acetate and methanol extracts as well as the alkaloid fraction of Lycopodium clavatum L. (LC) from Lycopodiaceae growing in Turkey. Antioxidant activity of the LC extracts was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging method at 0.2 mg/ml using microplate-reader assay. Antiviral assessment of LC extracts was evaluated towards the DNA virus Herpes simplex (HSV) and the RNA virus Parainfluenza (PI-3) using Madin-Darby Bovine Kidney (MDBK) and Vero cell lines. Antibacterial and antifungal activities of the extracts were tested against standard and isolated strains of the following bacteria; Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Acinobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis as well as the fungi; Candida albicans and C. parapsilosis. All of the extracts possessed noteworthy activity against ATCC strain of S. aureus (4 μg/ml), while the LC extracts showed reasonable antifungal effect. On the other hand, we found that only the chloroform extract was active against HSV (16–8 μg/ml), while petroleum ether and alkaloid extracts inhibited potently PI-3 (16–4 μg/ml and 32–4 μg/ml, respectively). However, all of the extracts had insignificant antiradical effect on DPPH. In addition, we also analyzed the content of the alkaloid fraction of the plant by capillary gas chromatography-mass spectrometry (GC-MS) and identified lycopodine as the major alkaloid.     

A model in environmental training--The University / Elementary School / Municipality Cooperation

This study targets development of an effective training scheme model that can be implemented at elementary school level with focus on recovery and recycling of wasted papers in Turkey. For this purpose, three schools were chosen from a district within Istanbul. They were separated from one another as full intervention (FI), semi-intervention (SI) and control (C) schools. Different levels of educational activities carried out in the schools, mostly in the FI school, were directed toward being informative as regards recycling and the development of a positive attitude. Afterwards, in order to evaluate the effects of the training, paper wastes were collected in recycle bins placed at appropriate points in schools and weighed on a weekly basis. Quite a significant result was found (p = 0.0001), when the difference was calculated through the Kruskal Wallis Variance Analysis method, regarding the weekly average amount of paper in each of the three schools against per person. Furthermore, when the results were evaluated and compared as to the ones before the 2.5 months summer vacation and the ones after it, the seven measurements taken before (p = 0.001) and the eight taken afterwards (p = 0.0001), were found to have valid differences, once again, as against schools. The results show that the approach we provided to education is an effective method not only for the collection of paper wastes but also for applications in various areas of health education.     

New class of steroidal alkaloids from Fritillaria imperialis

Two members of a new class of C-nor-D-homo steroidal alkaloids, impranine (1). and dihydroimpranine (2). along with a new pyridyl-pregnane-type steroidal alkaloid, fetisinine (3). and a known base, korsevine (4). were isolated from the bulbs of Fritillaria imperialis. The structures of the compounds were established on the basis of spectroscopic techniques and some chemical transformations. Compounds 1 and 2 form a new class of steroidal alkaloids, named as "impranane."     

Controlled oxidation of calf thymus DNA to produce standard samples for 8-oxodeoxyguanosine analysis; effects of freeze-drying, storage and hydrolysis conditions

Calf thymus DNA containing defined levels of 8-hydroxy-2'-deoxyguanosine (8-oxodG) was prepared by treatment with visible light in the presence of photosensitiser Ro 19-8022. The DNA was checked for stability; after freeze-drying, the amount of 8-oxodG did not increase during 6 weeks' storage at room temperature. However, freeze-drying itself can introduce additional oxidative damage. Two enzymic hydrolysis regimes (DNase I, phosphodiesterases I and II, and alkaline phosphatase; or P1 nuclease and alkaline phosphatase) give similar values for 8-oxodG.     

The protective effect of oxytocin on renal ischemia/reperfusion injury in rats

AIM: Oxytocin was previously shown to have anti-inflammatory effects in different inflammation models. The major objective of the present study was to evaluate the protective role of oxytocin (OT) in protecting the kidney against ischemia/reperfusion (I/R) injury. MATERIALS AND METHODS: Male Wistar albino rats (250-300 g) were unilaterally nephrectomized, and subjected to 45 min of renal pedicle occlusion followed by 6 h of reperfusion. OT (1 mg/kg, ip) or vehicle was administered 15 min prior to ischemia and was repeated immediately before the reperfusion period. At the end of the reperfusion period, rats were decapitated and kidney samples were taken for histological examination or determination of malondialdehyde (MDA), an end product of lipid peroxidation; glutathione (GSH), a key antioxidant; and myeloperoxidase (MPO) activity, an index of tissue neutrophil infiltration. Creatinine and urea concentrations in blood were measured for the evaluation of renal function, while TNF-alpha and lactate dehydrogenase (LDH) levels were determined to evaluate generalized tissue damage. Formation of reactive oxygen species in renal tissue samples was monitored by chemiluminescence technique using luminol and lucigenin probes. RESULTS: The results revealed that I/R injury increased (p<0.01-0.001) serum urea, creatinine, TNF-alpha and LDH levels, as well as MDA, MPO and reactive oxygen radical levels in the renal tissue, while decreasing renal GSH content. However, alterations in these biochemical and histopathological indices due to I/R injury were attenuated by OT treatment (p<0.05-0.001). CONCLUSIONS: Since OT administration improved renal function and microscopic damage, along with the alleviation of oxidant tissue responses, it appears that oxytocin protects renal tissue against I/R-induced oxidative damage.