Melatonin treatment for prevention of oxidative stress: involving histopathological changes

This study was undertaken to test the effect of irradiation on the histopathology of the hypothalamus and cerebral cortex. In addition, the probable effects of radiotherapy on the activities of antioxidant enzymes and levels of nitric oxide (NO) in the plasma were investigated as well. The effects of melatonin treatment on radiotherapy-based central nervous system (CNS) damage were also studied. For this purpose, the rats were randomized into four groups. The first group was the control group (sham-exposed group), the second group received only melatonin, the third group was irradiated and the fourth group received both melatonin and irradiation. Plasma samples of rats were collected for measuring the activities of superoxide dismutase (SOD), catalase (CAT) and the levels of NO. 24 h after the interventions, tissue samples were obtained from the hypothalamus and the cerebral cortex for the light microscopic investigations. These tissues were mostly affected by radiation. The results indicated that the application of radiation significantly enhanced the levels of plasma SOD and NO. On the other hand, melatonin pretreatment prevented the decrease in plasma CAT activity induced by irradiation. It was found that the application of melatonin could significantly prevent the irradiation-induced damages. Light microscopic results revealed that the damage of the CNS by radiation was prevented by the application of melatonin.     

Comparative morphometric analysis of intraepidermal and dermal lymphocytes in early mycosis fungoides and some inflammatory dermatoses

OBJECTIVE: Early stage mycosis fungoides (MF) may be indistinguishable from some inflammatory dermatoses (IDs) histopathologically. Various morphologic features of lymphocytes in epidermis and dermis may help to differentiate early-stage MF from other IDs. STUDY DESIGN: We studied 25 cases of early-stage MF and 30 cases of various IDs with prominent exocytosis. The following nuclear variables were measured on dermal and epidermal lymphocytes in MF and IDs (control) groups: nuclear area and perimeter, area convex hull, perimeter convex hull, diameter equivalent circle, minimum feret, maximum feret and form factor. All measurements were done using routinely prepared and hematoxylin-eosin-stained slides. RESULTS: There were statistically significant differences (p < 0.01) for all of the morphometric variables between early-stage MF and IDs. CONCLUSION: Our results revealed that the nuclear contour irregularities of intraepidermal lymphocytes are higher than those of dermal lymphocytes in MF. Their nuclear geometry is also different. Comparison of the nuclear features of intraepidermal with dermal lymphocytes may provide additional support in the diagnosis of early-stage MF.     

Relationship of aerobic and anaerobic parameters with 400 m front crawl swimming performance

The aims of the present study were to investigate the relationship of aerobic and anaerobic parameters with 400 m performance, and establish which variable better explains long distance performance in swimming. Twenty-two swimmers (19.1±1.5 years, height 173.9±10.0 cm, body mass 71.2±10.2 kg; 76.6±5.3% of 400 m world record) underwent a lactate minimum test to determine lactate minimum speed (LMS) (i.e., aerobic capacity index). Moreover, the swimmers performed a 400 m maximal effort to determine mean speed (S400m), peak oxygen uptake (V.O2PEAK) and total anaerobic contribution (C_ANA). The C_ANA was assumed as the sum of alactic and lactic contributions. Physiological parameters of 400 m were determined using the backward extrapolation technique (V.O2PEAK and alactic contributions of C_ANA) and blood lactate concentration analysis (lactic anaerobic contributions of C_ANA). The Pearson correlation test and backward multiple regression analysis were used to verify the possible correlations between the physiological indices (predictor factors) and S400m (independent variable) (p < 0.05). Values are presented as mean ± standard deviation. Significant correlations were observed between S400m (1.4±0.1 m·s^-1) and LMS (1.3±0.1 m·s^-1; r = 0.80), V.O2PEAK (4.5±3.9 L·min^-1; r = 0.72) and C_ANA (4.7±1.5 L·O₂; r= 0.44). The best model constructed using multiple regression analysis demonstrated that LMS and V.O2PEAK explained 85% of the 400 m performance variance. When backward multiple regression analysis was performed, C_ANA lost significance. Thus, the results demonstrated that both aerobic parameters (capacity and power) can be used to predict 400 m swimming performance.     

Temozolomide-related infections: review of the literature

Temozolomide (TMZ) is an alkylating, antineoplastic agent which is being used to treat cases of refractory anaplastic astrocytoma, newly-diagnosed glioblastoma multiforme and metastatic melanoma. TMZ causes lymphopenia and T-cell dysfunction in most of the patients. Related to this toxicity several opportunistic infections have been reported in the literature, but were not well characterized. To further investigate this topic, relevant English language studies were identified through Medline. There were 36 previously reported cases of infection related to TMZ. The median age of the cases was 55 years (range 33-73). The most frequently experienced infections were mucocutaneous candidiasis (n=11; 28.2%), herpes zoster (n=5; 12.8%), herpes simplex virus (n=4; 10.2%), cytomegalovirus (CMV) (n=5; 12.8%), pneumocystis carinii pneumonia (PCP) (n=3; 7.6%), hepatitis B virus (HBV) (n=2; 5.1%) and others (n=9; 23%). Mortality rates were 28.5% (n=4/14) in patients with reported outcome. In this survey, about one third of the TMZ-related severe infections resulted in death. Patients treated with TMZ are at increased risk for opportunistic viral and bacterial infection. Therefore, close monitoring of patients receiving TMZ for opportunistic infections should be carried out.     

Alien marine fishes deplete algal biomass in the Eastern Mediterranean

One of the most degraded states of the Mediterranean rocky infralittoral ecosystem is a barren composed solely of bare rock and patches of crustose coralline algae. Barrens are typically created by the grazing action of large sea urchin populations. In 2008 we observed extensive areas almost devoid of erect algae, where sea urchins were rare, on the Mediterranean coast of Turkey. To determine the origin of those urchin-less 'barrens', we conducted a fish exclusion experiment. We found that, in the absence of fish grazing, a well-developed algal assemblage grew within three months. Underwater fish censuses and observations suggest that two alien herbivorous fish from the Red Sea (Siganus luridus and S. rivulatus) are responsible for the creation and maintenance of these benthic communities with extremely low biomass. The shift from well-developed native algal assemblages to 'barrens' implies a dramatic decline in biogenic habitat complexity, biodiversity and biomass. A targeted Siganus fishery could help restore the macroalgal beds of the rocky infralittoral on the Turkish coast.     

A computational investigation of kinetoplastid trans-splicing

Trans-splicing is an unusual process in which two separate RNA strands are spliced together to yield a mature mRNA. We present a novel computational approach which has an overall accuracy of 82% and can predict 92% of known trans-splicing sites. We have applied our method to chromosomes 1 and 3 of Leishmania major, with high-confidence predictions for 85% and 88% of annotated genes respectively. We suggest some extensions of our method to other systems.     

The effect of melatonin on lipid peroxidation and nitrite/nitrate levels, and on superoxide dismutase and catalase activities in kainic acid-induced injury

Kainic acid (KA) initiates neuronal injury and death by inducing oxidative stress and nitric oxide release from various regions of the brain. It was recently shown that melatonin has free radical-scavenging action and may protect against kainate-induced toxicity. In order to assess the possible supportive effect of melatonin treatment in KA-induced injury in the rat brain cortex, we determined malondialdehyde (MDA) levels as an index of lipid peroxidation, and assessed the activities of catalase (CAT) and superoxide dismutase (SOD) and the levels of nitrite/nitrate 35 male rats were divided into five groups, each receiving a different intraperitoneal treatment: saline solution (0.2 ml), kainic acid (15 mg/kg), melatonin (20 mg/kg), KA then melatonin (each as above, 15 min apart), or melatonin then KA (each as above, 30 min apart). Administration of KA caused an about five-fold increase in the catalase activity and an increase in the SOD activity in the cortex relative to the activities for the controls. Treatment with melatonin 15 min after KA injection kept malondialdehyde levels and catalase and superoxide dismutase activities at the normal levels, and led to an increase in the levels of nitrite/nitrate. Our data suggests that melatonin treatment following KA administration has a protective effect on antioxidant enzyme activities and thus supports the role of melatonin and oxidative stress in the regulation of antioxidative enzyme activity.