Oxidative stress status assessment of rats' brains injury following subacute exposure to K-oximes

Oxidative stress status and morphological injuries in the brain of Wistar rats induced by repeated application of selected acetylcholinesterase reactivators - asoxime, obidoxime, K027, K048, K074, and K075 were evaluated. Each oxime in a dose of 0.1 of LD50/kg im was given 2x/week for 4 weeks. Markers of lipid peroxidation (malondialdehyde, MDA), and protein oxidation (advanced oxidation protein products, AOPP), as well as the activity of antioxidant enzymes (catalase, CAT, superoxide dismutase, SOD, glutathione reductase, GR, and glutathione peroxidase, GPx), were estimated in the brain tissue homogenates on day 35 of the study. Brain alterations were carefully quantified by semiquantitative grading scales - brain damage score (BDS). Oxidative stress parameters, MDA and AOPP were significantly highest in the asoxime-, obidoxime- and K075-treated groups (p < 0.001). The activity of SOD and CAT was significantly elevated in the obidoxime-, K048-, and K075-treated groups (p < 0.001). Besides, GR was markedly decreased in the obidoxime- and K074-treated groups (p < 0.01), while treatment with K048, K074 and K075 induced extremely high elevation in GPx levels (p < 0.001). In the same groups of rats, brain alterations associated with polymorphonuclear cell infiltrate were significantly more severe than those observed in animals receiving only asoxime or K027 (p < 0.001). The presented results confirmed that treatment with different oximes significantly improved the oxidative status and attenuated signs of inflammation in rats' brains. Presented results, together with our previously published data can help to predict likely adverse systemic toxic effects, and target organ systems, which are crucial for establishing risk categories, as well as in dose selection of K-oximes as drug candidates.

Overexpression of MRP1/ABCC1, Survivin and BCRP/ABCC2 Predicts the Resistance of Diffuse Large B-Cell Lymphoma to R-CHOP Treatment

BACKGROUND

Approximately 40% of patients with diffuse large B-cell lymphoma (DLBCL) experience treatment resistance to the first-line R-CHOP regimen. ATP binding cassette (ABC) transporters and survivin might play a role in multidrug resistance (MDR) in various tumors. The aim was to investigate if the coexpression of ABC transporters and survivin was associated with R-CHOP treatment response.

METHODS

The expression of Bcl-2, survivin, P-glycoprotein/ABCB1, MRP1/ABCC1, and BCRP/ABCC2 was analyzed using immunohistochemistry in tumor specimens obtained from patients with DLBCL, and classified according to the treatment response as Remission, Relapsed, and (primary) Refractory groups. All patients received R-CHOP or equivalent treatment.

RESULTS

Bcl-2 was in strong positive correlation with clinical parameters and all biomarkers except P-gp/ABCB1. The overexpression of MRP1/ABCC1, survivin, and BCRP/ABCC2 presented as high immunoreactive scores (IRSs) was detected in the Refractory and Relapsed groups (p < 0.05 vs. Remission), respectively, whereas the IRS of P-gp/ABCB1 was low. Significant correlations were found among either MRP1/ABCC1 and survivin or BCRP/ABCC2 in the Refractory and Relapsed groups, respectively. In multiple linear regression analysis, ECOG status along with MRP1/ABCC1 or survivin and BRCP/ABCG2 was significantly associated with the prediction of the R-CHOP treatment response.

CONCLUSIONS

DLBCL might harbor certain molecular signatures such as MRP1/ABCC1, survivin, and BCRP/ABCC2 overexpression that can predict resistance to R-CHOP.

Research update on aflatoxins toxicity, metabolism, distribution, and detection: A concise overview

Serious health risks associated with the consumption of food products contaminated with aflatoxins (AFs) are worldwide recognized and depend predominantly on consumed AF concentration by diet. A low concentration of aflatoxins in cereals and related food commodities is unavoidable, especially in subtropic and tropic regions. Accordingly, risk assessment guidelines established by regulatory bodies in different countries help in the prevention of aflatoxin intoxication and the protection of public health. By assessing the maximal levels of aflatoxins in food products which are a potential risk to human health, it's possible to establish appropriate risk management strategies. Regarding, a few factors are crucial for making a rational risk management decision, such as toxicological profile, adequate information concerning the exposure duration, availability of routine and some novel analytical techniques, socioeconomic factors, food intake patterns, and maximal allowed levels of each aflatoxin in different food products which may be varied between countries.

Protective Effects of Simvastatin on Endotoxin-Induced Acute Kidney Injury through Activation of Tubular Epithelial Cells' Survival and Hindering Cytochrome C-Mediated Apoptosis

Increasing evidence suggests that apoptosis of tubular cells and renal inflammation mainly determine the outcome of sepsis-associated acute kidney injury (AKI). The study aim was to investigate the molecular mechanism involved in the renoprotective effects of simvastatin in endotoxin (lipopolysaccharide, LSP)-induced AKI. A sepsis model was established by intraperitoneal injection of a single non-lethal LPS dose after short-term simvastatin pretreatment. The severity of the inflammatory injury was expressed as renal damage scores (RDS). Apoptosis of tubular cells was detected by Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labeling (TUNEL assay) (apoptotic DNA fragmentation, expressed as an apoptotic index, AI) and immunohistochemical staining for cleaved caspase-3, cytochrome C, and anti-apoptotic Bcl-xL and survivin. We found that endotoxin induced severe renal inflammatory injury (RDS = 3.58 ± 0.50), whereas simvastatin dose-dependently prevented structural changes induced by LPS. Furthermore, simvastatin 40 mg/kg most profoundly attenuated tubular apoptosis, determined as a decrease of cytochrome C, caspase-3 expression, and AIs (p  <  0.01 vs. LPS). Conversely, simvastatin induced a significant increase of Bcl-XL and survivin, both in the strong inverse correlations with cleaved caspase-3 and cytochrome C. Our study indicates that simvastatin has cytoprotective effects against LPS-induced tubular apoptosis, seemingly mediated by upregulation of cell-survival molecules, such as Bcl-XL and survivin, and inhibition of the mitochondrial cytochrome C and downstream caspase-3 activation.

Tissue-protective effects of fullerenol C60(OH)24 and amifostine in irradiated rats

Polyhydroxylated fullerenes, named fullerenols (C(60)(OH)(n); n=12-26) are excellent antioxidants. Harmful effects of ionizing radiation on living organism are mainly mediated by free radical species and fullerenols attract an attention as a potential radioprotectors. Our preliminary investigations on mice and rats subjected to radiation injury show that fullerenol C(60)(OH)(24) provides high survival rate of irradiated small rodents. Radioprotective effect was comparable to that of the standard radioprotector amifostine. The aim of this study was to compare the efficacy of fullerenol C(60)(OH)(24) (10 and 100mg/kg i.p.) and amifostine (300 mg/kg i.p.) in protection of rats against harmful effects of ionizing radiation. The animals were whole-body irradiated by X-rays (8 MV). Both compounds were given 30 min before irradiation. In order to evaluate the general radioprotective efficacy of fullerenol and amifostine rats were irradiated with an absolutely lethal dose of X-rays (8 Gy) and their survival and body mass gain were monitored during the period of 30 days after irradiation. The aim of the second part of the study is to investigate the tissue-protective effects of tested compounds (100 mg/kg i.p. of fullerenol and 300 mg/kg i.p. of amifostine, 30 min before irradiation). It was carried out on rats irradiated with a sublethal dose of X-rays (7 Gy). Influence of ionizing radiation on hematopoesis as well as the radioprotective efficiency of the compounds given were evaluated by determining blood cell count during 28 days after irradiation. For this purpose the blood was taken from tail vein before irradiation and on the 3rd, 7th, 14th, 21st and 28th day after irradiation. In order to estimate the radioprotective effects of fullerenol and amifostine on other rat tissue, the animals were sacrificed on the 7th and 28th day after irradiation and their main organs (lung, heart, liver, kidney, small intestine and spleen) were taken for histopathological analysis. In the experiment in which the general radioprotective efficacy of fullerenol and amifostine was examined, fullerenol given in a dose of 100mg/kg produced better protection than given in a dose of 10mg/kg. This effect was comparable to that of amifostine. The results of hematological investigations showed that fullerenol better than amifostine prevented radiation-induced reduction in the white cell count (granulocytes and lymphocytes), particularly in the first 7 days after irradiation. Pathohistology examinations revealed better radioprotective effects of fullerenol compared to those of amifostine on the spleen, small intestine and lung, while amifostine had better radioprotective effects than fullerenol in protection of the heart, liver and kidney. These results confirm satisfactory radioprotective efficacy of fullerenol and encourage further investigations as a potential radioprotector.

Diuretic activity of Maydis stigma extract in rats

Maydis stigma (corn silk) is a herbal drug reputed for the treatment of urinary ailments in various traditional medicine systems. To determine its influence on urinary volume and the excretion of sodium, potassium and chloride, 5% and 10% decoctions were administered daily to adult male Wistar rats for eight days. The concentration of electrolytes and urea in plasma, the influence of treatment on urinary pH value as well as creatinine clearance were also investigated. Daily oral administration of 5% decoction at the dose of 10 ml/kg led to a significant and acute diuresis in rats, reaching the peak value in the first 24 h of treatment. Over a similar period, application of 10% decoction did not affect urinary excretion of water, but significantly increased the pH value of excreted urine. A significant decrease in sodium and chloride plasma levels was observed in both treated groups. The creatinine clearance was markedly increased after the treatment with both extracts. Our findings indicate that the diuretic effect of 5% aqueous Maydis stigma extract is in accordance with the increase in glomerular filtration rate and inhibition of sodium and chloride tubular reabsorption, caused a by still unidentified intrinsic factor, but not the salt-loading effect.

[Principles of lymph node surgery in differentiated thyroid carcinoma]

Surgery is the initial therapy in differentiated thyroid carcinoma (DTC). The surgery is performed on organ of tumor origin and regional lymphatic basins. The aim of surgery in DTC is to eradicate all tumor foci, cure the most number of patients, reduce recurrence and mortality rate, and provide good quality of life. There is no doubt between oncologists that the surgery for thyroid carcinoma has no alternative. The extent of surgery is matter of actual controversies. It should be performed by well trained surgeons. Dissection of central and biopsy of supraclavicular and lower third of jugulo-carotid chain of neck lymph nodes is the integral part of surgery in DTC, together with total thyroidectomy. If lymph node metastases are found in jugulo-carotid chain, modified radical neck dissection, unilateral or bilateral is indicated. Dissection of mediastinal lymph nodes should be performed too in cases of involvement. The extent of primary surgery should be dictated by stage of disease and prognostic factors. The quality of surgery and incidence of complications depends prognostic factors, as well as on surgeon's skill and experience. That is why the surgeon is factor of prognosis in treatment of patients with DTC.

[Identification of sentinel lymph nodes in thyroid carcinoma]

Sentinel lymph node (SLN) was defined as the first lymph node that the tumor would drain to, within that tumors regional lymphatic basin. In 1998, Kelemen and coworkers have published the first results on SLN lymphonodectomy in thyroid carcinomas. Different methods have been used in a goal of lymphatic mapping (application of vital blue dye and/or radiocolloid). In a period from 2001 to 2003 we have performed SLN biopsy in 64 patients with thyroid tumors. There were 12 cases of thyroid carcinoma. SLN identification rate was 73.44%. We found no false positive or negative results on definitive histopathology. The impact of lymph node metastases in differentiated thyroid carcinoma is still controversial. The management of cervical lymph nodes varies from berry picking to modified radical neck dissection. There is a significant disproportion in percentage of pre and intraoperatively enlarged lymph nodes (27-45%) and histologically confirmed lymph node metastases (80-90%) in papillary thyroid carcinoma. In the current literature the average rate of SLN identification is 91% (66-100%) and when identified, the SLN accurately predicts the disease status of the neck in most patients (80-100%). The SLN biopsy for thyroid carcinoma is good and feasible technique for estimating the cervical lymph node status.

Polyhydramnios and arterio-arterial placental anastomoses may beneficially affect monochorionic twin pregnancies

Our objective was to appraise whether an increased amniotic fluid pressure by polyhydramnios can beneficially affect monochorionic twins that are haemodynamically connected by arterio-venous plus arterio-arterial placental anastomoses. We assessed the effects of polyhydramnios in monochorionic twin placentas, combining (a) data from previous in vitro placental perfusion experiments in singleton term placentas under simulated normal and increased amniotic fluid pressures with (b) logical deduction from observations made in monochorionic twins. Our hypothesis is that in monochorionic placentas, an increased amniotic fluid pressure increases the placental microvascular resistance but not the resistance of placental chorionic plate arteries. Hence, an increased amniotic fluid pressure increases the microvascular resistance of the joint cotyledon, the arterio-venous resistance, but not the arterioarterial resistance. This proposed mechanism reduces arterio-venous but not oppositely directed arterio-arterial transfusion. Therefore, reversal of the normal direction of net foeto-foetal transfusion may develop, which will reduce the circulatory imbalance that evolved between the monochorionic foetal twins. In contrast, in monochorionic twins connected by unidirectional or bidirectional arterio-venous anastomoses reversal of the normal direction of net foeto-foetal transfusion will not occur. In conclusion, reversal of the normal direction of net foeto-foetal transfusion, induced by polyhydramnios, is protective against the onset and severity of twin-twin transfusion syndrome in monochorionic twins connected by arterio-venous plus arterio-arterial anastomoses, but not by unidirectional or bidirectional arterio-venous anastomoses.