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1.
Since the exact mechanism of manganese (Mn)-induced learning disability is not known, we investigated the role of elevated
cholesterol in rats exposed daily to 357 and 714 μg Mn/kg for 30 d. Significant Mn accumulation was accompanied by increased
cholesterol content in the hippocampal region of Mn-treated rats. The learning, which is based on the time needed to reach
food placed at the exit of a T-maze after a 1-d training period, was significantly slower in exposed rats than in unexposed
rats. The rats receiving 357 and 714 μg Mn/kg reached the food in 104.5±13.8 and 113.3±25.7 s, respectively, on d 30, whereas
their untreated counterparts reached the food in 28.7±11.4 s. This delay was completely corrected to 29.3±7.8 and 30.7±6.0
s in rats with coadministration of an inhibitor of cholesterol biosynthesis with 357 and 714 μg/kg of Mn. The correction of
impaired learning was associated with the normalization of hippocampal cholesterol, but the Mn level in this region of the
brain was not influenced in rats treated with a drug that inhibits cholesterol biosynthesis. These results suggested that
Mn-induced hypercholesterolemia is involved in Mn-dependent learning disability. 相似文献
2.
The protective effect of arbutin against potassium bromate-induced oxidative damage in the rat brain
H. Turan Akkoyun Ahmet Uyar Mahire Bayramoglu Akkoyun Aydın Şükrü Bengü Şule Melek Fatma Karagözoğlu Sevinç Aydın Suat Ekin Sinem Aslan Erdem 《Journal of biochemical and molecular toxicology》2023,37(2):e23248
This study aimed to investigate the protective effects of arbutin (ARB) against brain injury induced in rats with potassium bromate (KBrO3). The rats were divided into four groups as Group 1: Control (0.9% NaCl ml/kg/day p.), Group 2: KBrO3 (100 mg/kg (gavage), Group 3: ARB (50 mg/kg/day p.), and Group 4: KBrO3 + ARB (100 mg/kg (gavage) + 50 mg/kg/day p.). At the end of the fifth day of the study, the rats in all groups were killed, and their brain tissues were collected. In the collected brain tissues, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) levels were measured, and routine histopathological examinations were made. The MDA levels in the group that was exposed to KBrO3 were significantly higher than those in the control group (p ˂ 0.001). In comparison to the KBrO3 group, the MDA levels in the KBrO3 + ARB group were significantly lower (p ˂ 0.001). It was observed that SOD and CAT enzyme activity levels were significantly lower in the KBrO3 group compared to the control group (p ˂ 0.001), while these levels were significantly higher in the KBrO3 + ARB group than in the KBrO3 group (p ˂ 0.001). Additionally, the group that was subjected to KBrO3 toxicity, as well as ARB administration, had much lower levels of histopathologic signs than the group that was subjected to KBrO3 toxicity only. Consequently, it was found that KBrO3 exposure led to injury in the brain tissues of the rats, and using ARB was effective in preventing this injury. 相似文献
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Ellie E. Dyer Victoria Franks Phillip Cassey Ben Collen Robert C. Cope Kate E. Jones Çagan H. Şekercioğlu Tim M. Blackburn 《Global Ecology and Biogeography》2016,25(11):1346-1355
Aim Determining the causes of range size variation in the distributions of alien species is important for understanding the spread of invasive species. Factors influencing alien range size have been explored for some species at a regional level, but to date there has been no global analysis of an entire class. Here, we present such an analysis for birds, testing for the effects of introduction event, location and species‐level variables on alien range sizes. Location Global. Methods We used a novel dataset on the global distributions of alien bird species to test for relationships between alien range size and colonization pressure, residence time, extent of the global climatic niche, native range size, body mass and specialization, using a statistical approach based on phylogenetic generalized least squares models. We performed this analysis globally, and for separate biogeographical realms. Results Approximately half of the variation in alien bird range size is explained by colonization pressure in univariate analysis. We identified consistent effects of higher colonization pressure at global and realm levels, as well as support for effects of native range size and residence time. We found less support for effects of body mass, specialization or extent of the global climatic niche on alien range size. Main conclusions Alien bird range sizes are generally small relative to their native range sizes, and many are continuing to expand. Nevertheless, current variation is predictable, most strongly by the event‐level factor of colonization pressure. Whether a species is widespread is a better predictor of alien range size than whether a species could be widespread (estimated by global climatic niche extent), while we also find effects of residence time on alien range size. These relationships may help to identify those alien species that are more likely to spread and hence have greater environmental and economic impacts where they have been introduced. 相似文献
5.
Summary Partitioning behaviour and adsorption isotherms of lactase/CM-Sephadex system at equilibrium were investigated together with the adsorption kinetics in this study. Maximum adsorption was obtained at the pH values between 5.5–6.0. Adsorption isotherm was a close fit to the Langmuir model.Nomenclature a
specific mass transfer area
- Dm
molecular diffusion coefficient (m2/sec)
- e1, e2
charge of the protein and the gel
- k
apparent mass transfer coefficient (s-1)
- ka
global mass transfer coefficient
- f
partition coefficient
- Kp
dissociation constant for adsorbent-adsorbate complex, (mg/mL solvent)
- p
equilibrium concentration of free enzyme, (mg free enzyme/mL solution)
- q
equilibrium concentration of adsorbed enzyme, (mg ads./mL gel)
- qm
maximum adsorption capacity, (mg ads./ml gel)
- Re
particle Reynolds number
- Sh
Sherwood number
- Vg/V
gel volume (mL)/bulk solvent volume (mL)
- Z
dimensionless extent of adsorption
-
Kp/Po , model parameter
-
(/) +1 , model parameter
-
Vg qm / V Po , model parameter 相似文献
6.
Summary In this paper genetic, clinical, and epidemiological studies on a muscular dystrophy which originated and is concentrated in the village of Çullar, Nevehir of inland Turkey, are reported. A pedigree chart has been constructed by careful and repeated inquiries, and both clinical and laboratory examinations have generally been carried out in the field. The consideration, facioscapulohumeral muscular dystrophy of Landouzy-Déjérine, has been found to have affected at least 53 individuals, 9 of whom are deceased. Both sexes in six generations are involved as would be expected from a dominant mendelian gene freshly mutated at least 100 years ago. Additionally, some 19 individuals have been described as having the disease or some of its stigmata, but have not been examined by us. Initial signs and symptoms seem to appear early in infancy, though variable, and because of complete dominance, some 75 individuals are at risk. The disease progresses slowly without interfering significantly with survival and reproduction. For prevention the so-called Çullar example measures have been taken to improve the area culturally and socioeconomically. 相似文献
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Yılmaz Baş Nermin Koç Kaan Helvacı Cem Koçak Raşit Akdeniz Havva Hande Keser Şahin 《Translational oncology》2021,14(2):100994
We investigated programmed cell death 1 (PD-1) / programmed cell death ligand 1 (PD-L1) expression in high grade serous ovarian cancer (HGSOC) and its relationship to tumor infiltrating lymphocytes (TIL) and prognosis. Formalin fixed paraffin embedded (FFPE) samples of 94 HGSOC cases were included in the study. Immunohistochemical analysis (CD3, CD4, CD8, PD-1 and PD-L1) was performed. Samples were analyzed for expression of immune proteins in the peritumoral stromal and intratumoral areas, scored, and expression was correlated with overall survival, stage, and age. PD-L1 staining ratio with a score greater than 0 was found to have lower survival. There were two positive staining patterns, patchy/diffuse and patchy/focal patterns, in 24 (25.5%) cases. Considering the threshold value ≥5%, we demonstrated that the PD-L1 positive cancer cell membrane immunoreactivity rate and patchy/diffuse PD-L1 expression were 9.6% (n = 9). There was statistically significant relationship between high PD-1 scores and PD-L1 cases of ≥ 5%. A statistically significant difference was found between PD-L1 staining and survival in patients with a threshold ≥ 5%. However an appropriate rate for treatment was determined in 9.6% cases. There was a statistically significant correlation between PD-1 positive TIL score and intratumoral CD3, peritumoral stromal CD3, intratumoral CD4 and intratumoral CD8 positive cells. Survival was lower in cases with higher PD-L1 positive stromal TIL score. 相似文献
9.
Elif Tatlidede Özer Şehirli Ayliz Velioğlu-Öğünç Şule Çetinel Berrak Ç. Yeğen Ayşen Yarat 《Free radical research》2013,47(3):195-205
The possible protective effects of resveratrol (RVT) against cardiotoxicity were investigated in Wistar albino rats treated with saline, saline+doxorubicin (DOX; 20 mg/kg) or RVT (10 mg/kg)+DOX. Blood pressure and heart rate were recorded on the 1st week and on the 7th week, while cardiomyopathy was assessed using transthoracic echocardiography before the rats were decapitated. DOX-induced cardiotoxicity resulted in decreased blood pressure and heart rate, but lactate dehydrogenase, creatine phosphokinase, total cholesterol, triglyceride, aspartate aminotransferase and 8-OHdG levels were increased in plasma. Moreover, DOX caused a significant decrease in plasma total antioxidant capacity along with a reduction in cardiac superoxide dismutase, catalase and Na+,K+-ATPase activities and glutathione contents, while malondialdehyde, myelopreoxidase activity and the generation of reactive oxygen species were increased in the cardiac tissue. On the other hand, RVT markedly ameliorated the severity of cardiac dysfunction, while all oxidant responses were prevented; implicating that RVT may be of therapeutic use in preventing oxidative stress due to DOX toxicity. 相似文献
10.
Sevgi Yardim-Akaydin Aylin Sepici Yeşim Özkan Meral Torun Bolkan Şimşek Vesile Sepici 《Free radical research》2013,47(6):623-628
Free radicals are implicated in many diseases including atherosclerosis, cancer and also in rheumatoid arthritis. Reaction of uric acid with free radicals, such as hydroxyl radical and hypochlorous acid (HOCl) results in allantoin production. In this study, we measured the serum allantoin levels, oxidation products of uric acid, as a marker of free radical generation in rheumatoid arthritis. Fasting blood samples were obtained from 21 rheumatoid patients and 15 healthy controls. In this study, the serum allantoin and uric acid levels were measured by a gas chromatography–mass spectrometry method and the ratios were calculated. The mean allantoin and uric acid levels and ratios in the patient group were 22.1±11.3, 280.5±65.0 and 8.0±3.7?μM, while in the control group they were 13.6±6.3, 278.3±53.6 and 4.9±2.1?μM, respectively. The effects of gender, age, menopausal status, duration of disease and medications on serum allantoin and uric acid levels of the patient and control groups were studied. Our results suggest that uric acid acts as a free radical scavenger and thus is converted to allantoin. Increased allantoin levels suggest the possible involvement of free radicals in rheumatoid arthritis. 相似文献