Skeletal muscle post-conditioning by diazoxide, anti-oxidative and anti-apoptotic mechanisms

Pretreatment with diazoxide, K_ATP channel opener, increases tissue tolerance against ischemia reperfusion (IR) injury. In clinical settings pretreatment is rarely an option therefore we evaluated the effect of post-ischemic treatment with diazoxide on skeletal muscle IR injury. Rats were treated with either saline, diazoxide (K_ATP opener; 40?mg/kg) or 5-hydroxydecanoate (5-HD; mitochondrial K_ATP inhibitor; 40?mg/kg) after skeletal muscle ischemia (3?h) and reperfusion (6, 24 or 48?h). Tissue contents of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activities, Bax and Bcl-2 protein expression and muscle histology were determined. Apoptosis was examined (24 and 48?h) after ischemia. IR induced severe histological damage, increased MDA content and Bax expression (24 and 48?h; p?<?0.01) and decreased CAT and SOD activities (6 and 24?h, p?<?0.01 and 48?h, p?<?0.05), with no significant effect on Bcl-2 expression. Diazoxide reversed IR effects on MDA (6 and 24?h; p?<?0.05), SOD (6 and 24?h; p?<?0.01) and CAT (6 and 48?h, p?<?0.05 and 24?h p?<?0.01) and tissue damage. Diazoxide also decreased Bax (24 and 48?h; p?<?0.05) and increased Bcl-2 protein expression (24 and 48?h; p?<?0.01). Post-ischemic treatment with 5-HD had no significant effect on IR injury. Number of apoptotic nuclei in IR and 5-HD treated groups significantly increased (p?<?0.001) while diazoxide decreased apoptosis (p?<?0.01). The results suggested that post-ischemic treatment with diazoxide decrease oxidative stress in acute phase which modulates expression of apoptotic proteins in the late phase of reperfusion injury. Involvement of KATP channels in this effect require further evaluations.     

A Comparative Study of the Oxidative Profile in Graves’ Disease, Hashimoto’s Thyroiditis, and Papillary Thyroid Cancer

The aim of this study was to evaluate and compare the oxidative profiles of three thyroid disorders: Graves’ disease (GD), Hashimoto thyroiditis (HT), and papillary thyroid cancer (PTC). Malondialdehyde levels (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities were examined in the plasma of 52 patients (29 untreated HT, 16 untreated GD, and 7 PTC who underwent surgical therapy). Results were compared with those of 30 healthy controls and among the three groups of patients. The GD, HT, and PTC patients exhibited increased plasma MDA levels and SOD activities compared with the controls (p?<?0.05, p?<?0.05, and p?<?0.001, respectively). CAT activities significantly increased only for the PTC and HT patients (p?<?0.001 and p?<?0.05, respectively), whereas GPx activities significantly decreased only in the GD and PTC (p?<?0.05 and p?<?0.01, respectively). The comparison among the three groups of patients has shown increased MDA level and SOD activity for the PTC patients as compared to the GD patients (p?<?0.01 and p?<?0.001, respectively). Compared with HT, PTC patients exhibited significant higher MDA level, SOD, and CAT activities and a significant lower GPx activity (p?<?0.01, p?<?0.001, p?<?0.05, and p?<?0.05, respectively). No significant discrepancies were noted between the GD and HT patients. Our results have clearly shown an oxidative profile that is highly disturbed for the PTC patients as compared to those of autoimmune disorders. Future studies are needed to determine whether or not the oxidative stress has a prognostic value in this pathology.     

The evaluation of protective and mitigating effects of vitamin C against side effects induced by radioiodine therapy

The goal of this study was to evaluate the protective and mitigative effect of vitamin C on oxidative stress in differentiated thyroid cancer (DTC) patients ablated with radioiodine. 58 DTC patients selected for radioactive iodine therapy (RAIT) with 5550 MBq ¹³¹Iodine were divided into four groups. Group 1 (control group) consisted of patients who underwent RAIT routinely. Other patients received 1500 mg vitamin C daily 2 days after (group 2), 2 days before to 2 days after (group 3) and 2 days before RAIT (group 4). Serum oxidative stress markers including malondialdehyde (MDA), glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) were measured immediately before and 2 days after RAIT. A significant increase in MDA after RAIT was observed in all groups (p?<?0.05). The concentrations of MDA were significantly higher in the control group compared to the intervention groups (p?<?0.05). A significant decrease in the control group (p?<?0.05) and increase in group 4 (p?<?0.05) were observed in GSH level after RAIT (p?<?0.05). Mean variation of GSH was significant between control group with groups 3 (p?<?0.01) and 4 (p?<?0.01). The results indicate that activity of SOD remained unchanged in all groups (p?>?0.05). A significant increase was observed in CAT activity after RAIT in all groups (p?<?0.05), which was higher in control group than intervention groups. In groups 3 (p?<?0.05) and 4 (p?<?0.05), this increase in CAT activity was significantly lower than the control group. RAIT causes serum oxidative stress, which can be ameliorated using vitamin C as an antioxidant. These results indicate that radioprotective effect of vitamin C is preferable to its mitigative effect.     

Comparative Analysis of the Protective Effects of Caffeic Acid Phenethyl Ester (CAPE) on Pulmonary Contusion Lung Oxidative Stress and Serum Copper and Zinc Levels in Experimental Rat Model

The aim of this study was to investigate the effects of caffeic acid phenethyl ester (CAPE) in the lungs by biochemical and histopathological analyses in an experimental isolated lung contusion model. Eighty-one male Sprague–Dawley rats were used. The animals were divided randomly into four groups: group 1 (n?=?9) was defined as without contusion and without CAPE injection. Group 2 (n?=?9) was defined as CAPE 10 μmol/kg injection without lung contusion. Group 3 (n?=?36) was defined as contusion without CAPE-administrated group which consisted of four subgroups that were created according to analysis between days?0, 1, 2, and 3. Group 4 (n?=?27) was defined as CAPE 10 μmol/kg administrated after contusion group divided into three subgroups according to analysis on days?1, 2, and 3. CAPE 10 μmol/kg was injected intraperitoneally 30 min after trauma and on days?1 and 2. Blood samples were obtained to measure catalase (CAT) and superoxide dismutase (SOD) activities and level of malondialdehyde (MDA) and for blood gas analysis. Trace elements such as zinc and copper were measured in serum. The lung tissue was also removed for histopathological examination. Isolated lung contusion increased serum and tissue SOD and CAT activities and MDA levels (p?<?0.05). Both serum and tissue SOD, MDA, and CAT levels on day?3 were lower in group 4 compared to group 3 (p?<?0.05). Further, the levels of SOD, MDA, and CAT in group 4 were similar compared to group 1 (p?>?0.05). CAPE also had a significant beneficial effect on blood gases (p?<?0.05). Both serum zinc and copper levels were (p?<?0.05) influenced by the administration of CAPE. Histopathological examination revealed lower scores in group 4 compared to group 3 (p?<?0.05) and no significant differences compared to group 1 (p?>?0.05). CAPE appears to be effective in protecting against severe oxidative stress and tissue damage caused by pulmonary contusion in an experimental setting. Therefore, we conclude that administration of CAPE may be used for a variety of conditions associated with pulmonary contusion. Clinical use of CAPE may have the advantage of prevention of pulmonary contusion.     

Protective Effects of Quercetin Against Cadmium Chloride-Induced Oxidative Injury in Goat Sperm and Zygotes

Quercetin, a plant-derived flavonoid, is frequently used as an antioxidant for efficient anti-oxidative capacity. However, whether quercetin has protective effects on goat sperm and preimplantation embryos against Cd²⁺-induced oxidative injury is still unclear. So, we researched the influence of quercetin on goat sperm and zygotes respectively under the oxidative stress induced by Cd²⁺. In our study, quercetin decreased the malonaldehyde (MDA) and reactive oxygen species (ROS) levels caused by Cd²⁺ in goat sperm (p?<?0.05), which facilitated sperm characteristics including motility, survival rates, membrane integrity, and mitochondria activity during storage in vitro and subsequent embryo development (p?<?0.05). Moreover, in goat zygotes, quercetin decreased peroxidation products including ROS, MDA, and carbonyl through preserving or maintaining mitochondrial function, gene expression, and anti-oxidative products such as glutathione peroxidase, superoxide dismutase, and catalase, which ameliorated subsequent embryo development and embryo quality (p?<?0.05). Taken together, these results suggest that quercetin protects both goat sperm and preimplantation embryos from Cd²⁺-induced oxidative stress.     

Effects of Zinc on Interleukins and Antioxidant Enzyme Values in Psoriasis-Induced Mice

The effects of zinc chloride (ZnCl₂), disodium zinc ethylenediamine tetraacetate (Zn-EDTA), and zinc gluconate (Zn-GLU) on the antioxidant enzyme activities and levels of interleukins (ILs) in psoriasis-induced mice were studied. One hundred twenty female mice were randomly divided into six groups with 20 mice in each group: the control, positive control (PC), methotrexate (MTX), ZnCl₂, Zn-EDTA, and Zn-GLU groups. All animals except the control group were given diethylstilbestrol for three consecutive days. After successfully inducing psoriasis, the control and PC groups were given normal saline (i.g.) daily while the remaining groups were given MTX, ZnCl₂, Zn-EDTA, and Zn-GLU, respectively. The results revealed that the zinc supplementation could significantly (p?<?0.05) inhibit mitosis in the mouse vaginal epithelium as methotrexate did and the inhibiting efficacy had nothing to do with the zinc forms. After ZnCl₂, Zn-EDTA, and Zn-GLU supplementation, the levels of liver superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities increased and the concentration of malondialdehyde (MDA) decreased significantly (p?<?0.05) compared to the PC group. The levels of SOD, CAT activity, and MDA level between each zinc supplementation group and MTX group were insignificant (p?>?0.05). The zinc treatments also caused a significant (p?<?0.05) decrease in the raised IL-2 level of animal serum. The results obtained in the present work indicate the potential for zinc as a complementary pharmaceutical intervention for the treatment of topical psoriasis.     

The Regulation of Exogenous Jasmonic Acid on UV-B Stress Tolerance in Wheat

Enhanced ultraviolet-B radiation (UV-B, 280?C320?nm) is recognized as one of the environmental stress factors that cannot be neglected. Jasmonic acid (JA) is an important signaling molecule in a plant??s defense against biotic and abiotic stresses. To determine the role of exogenous JA in the resistance of wheat to stress from UV-B radiation, wheat seedlings were exposed to 0.9?kJ?m^?2?h^?1 UV-B radiation for 12?h after pretreatment with 1 and 2.5?mM JA, and the activity of antioxidant enzymes, the level of malondialdehyde (MDA), the content of UV-B absorbing compounds, photosynthetic pigments, and proline and chlorophyll fluorescence parameters were measured. The results of two-way ANOVA illustrated that the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), MDA level, anthocyanin and carotenoid (Car) content, and almost all chlorophyll fluorescence parameters were significantly affected by UV-B, JA, and UV-B?×?JA (P?<?0.05) [the maximal efficiency of photosystem II photochemistry (F _v/F _m) was not affected significantly by UV-B radiation]. Duncan??s multiple-range tests demonstrated that UV-B stress induced a significant reduction in plant photosystem II (PSII) function and SOD activity and an increased level of membrane lipid peroxidation, indicative of the deleterious effect of UV-B radiation on wheat. JA pretreatment obviously mitigated the detrimental effect of UV-B on PSII function by increasing F _v/F _m, reaction centers?? excitation energy capture efficiency (F _v??/F _m??), effective photosystem II quantum yield (??PSII), and photosynthetic electron transport rate (ETR), and by decreasing nonphotochemical quenching (NPQ) of wheat seedlings. Moreover, the activity of SOD and the content of proline and anthocyanin were provoked by exogenous JA. However, the MDA level was increased and Car content was decreased by exogenous JA with or without the presence of supplementary UV-B, whereas the contents of chlorophyll and flavonoids and related phenolics were not affected by exogenous JA. Meanwhile, exogenous JA resulted in a decrease of CAT and POD activities under UV-B radiation stress. These results partly confirm the hypothesis that exogenous JA could counteract the negative effects of UV-B stress on wheat seedlings to some extent.     

The effect of zinc on the growth and physiological and biochemical parameters in seedlings of Eruca sativa (L.) (Rocket)

Eruca sativa seedlings were treated with different Zn concentrations (0, 250, 500, 1,000, 2,000 μg g^?1 dried growth medium) under controlled conditions. The seedlings were harvested 20 days after Zn treatment. Physiological parameters, such as root and shoot length, fresh and dry weight, were measured and Zn content of roots and shoots was determined. Furthermore, various biochemical parameters were studied on E. sativa leaves: enzymatic antioxidants, such as superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), and non-enzymatic antioxidants, such as ascorbate, non-protein thiols. Malondialdehyde, which is an index of lipid peroxidation, was assayed. Zn treatment did not have any significant effect on fresh and dry weights, whereas 500 μg g^?1 Zn increased root growth significantly (p < 0.05). Zn accumulated in roots 2–8 times more than it did in leaves. Lipid peroxidation increased in proportion with the increase in Zn. Although a decrease in SOD and CAT activities at increased Zn was found, a significant increase in APX and POD was observed at 500 and 1,000 μg g^?1 Zn, respectively. In addition, an increase in the amounts of non-protein thiols and total AsA (Ascorbate) was observed with the increase in Zn.     

210Po Activity and Concentrations of Selected Trace Elements (As, Cd, Cu, Hg, Pb, Zn) in the Muscle Tissue of Tunas Thunnus albacares and Katsuwonus pelamis from the Eastern Pacific Ocean

Daily mineral intake (DMI) of Cu and Zn, percentage weekly intake (PWI) of As, Cd, Hg, Pb, and doses of ²¹⁰Po were estimated by using their elemental concentration in muscle of two tuna species and the average tuna consumption in Mexico. Skipjack tuna Katsuwonus pelamis had significantly (p?<?0.05) higher levels of As (1.38???g?g^?1 dw) and Cu (1.85???g?g^?1 dw) than yellowfin tuna Thunnus albacares, whereas Pb concentrations (0.18???g?g^?1 dw) were significantly (p?<?0.05) higher in T. albacares. The sequence of elemental concentrations in both species was Zn?>?Cu?>?As?>?Hg?>?Pb?>?Cd. In T. albacares, concentrations of Cd and Pb in muscle tissue were positively correlated (p?<?0.05) with weight of specimens, while Cu was negatively correlated. DMI values were below 10?%. PWI figures (<2?%) are not potentially harmful to human health. ²¹⁰Po concentration in T. albacares and K. pelamis accounts for 13.5 to 89.7?% of the median individual annual dose (7.1???Sv) from consumption of marine fish and shellfish for the world population.     

Weight loss and regain in obese individuals: a link with adipose tissue metabolism indices?

This study was performed to examine whether changes in subcutaneous adipose tissue (SCAT) metabolism indices after weight loss were related to the magnitude of weight regain. Nine men and ten premenopausal women whose body mass index ranged from 30 to 42 kg/m², 35–48 years old, were studied before and after a 15-week weight loss program, as well as at a 17–22-month follow-up period. Although body composition was evaluated at all study periods, abdominal and femoral SCAT-lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) activities, and α2- and β-adrenoceptors (ARs) were measured before and after weight loss, exclusively. Although the SCAT-LPL activity did not change after weight loss in men, it tended to decrease in the femoral depot of women (p?=?0.06). SCAT-HSL activity remained unchanged after weight reduction in men, while the post-weight loss lipase activity tended to be higher in both regions of women (p?=?0.06). Although the post-weight loss number of β-ARs was higher irrespective of the fat depot (0.001?<?p?<?0.05), the number of α2-ARs was increased in the femoral (p?<?0.05), but not in the abdominal SCAT (p?=?0.08) after weight reduction, in men. Neither the α2- nor the β-AR density changed after weight reduction, in women. Abdominal SCAT-LPL activity after weight reduction was negatively related to weight regain indices, in women (?0.65?<?Rhô?<??0.75; 0.01?<?p?<?0.05). Both the post-weight loss abdominal SCAT α2-AR density and the α2-/β-AR balance were positively associated with weight regain indices, in men (0.69?<?Rhô?<?0.88; 0.01?<?p?<?0.05). These results suggest that selected SCAT metabolism indices could predict failure to weight loss maintenance, in both genders.     

Effects of Extremely Low-Frequency Magnetic Field on Caspase Activities and Oxidative Stress Values in Rat Brain

This study was aimed to investigate the effect of extremely low-frequency magnetic field (ELF-MF) on apoptosis and oxidative stress values in the brain of rat. Rats were exposed to 100 and 500 µT ELF-MF, which are the safety standards of public and occupational exposure for 2 h/day for 10 months. Brain tissues were immunohistochemically stained for the active (cleaved) caspase-3 in order to measure the apoptotic index by a semi-quantitative scoring system. In addition, the levels of catalase (CAT), malondialdehyde (MDA), myeloperoxidase (MPO), total antioxidative capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were measured in rat brain. Final score of apoptosis and MPO activity were not significantly different between the groups. CAT activity decreased in both exposure groups (p?<?0.05), while TAC was found to be lower in ELF 500 group than those in ELF-100 and sham groups (p?<?0.05). MDA, TOS, and OSI values were found to be higher in ELF-500 group than those in ELF-100 and sham groups (p?<?0.05). In conclusion, apoptosis was not changed by long-term ELF-MF exposure, while both 100 and 500 µT ELF-MF exposure induced toxic effect in the rat brain by increasing oxidative stress and diminishing antioxidant defense system.     

Abundance and community composition of bacterioplankton in the Northern South China Sea during winter: geographic position and water layer influences

The abundance and composition of bacterioplankton of the Northern South China Sea (NSCS) were investigated using flow cytometry and high-throughput sequencing. The results showed that the absolute abundance of bacterioplankton retained high values in surface waters at both continental shelf and oceanic sites and Proteobacteria, Cyanobacteria, and Bacteroidetes represented the three typical dominant phyla in NSCS. The average bacterioplankton abundances at 5 m, 75 m, and 200 m were 9.55, 5.04, and 1.32?×?10⁵ cells mL^?1, respectively, and there was a significantly positive correlation between bacterioplankton abundance and Chl a content (r?=?0.84, p?<?0.01). Drastic changes of the bacterioplankton community occurred in different water layers. Three operational taxonomic units (OTUs), whose distribution were significantly different between 5-m and 75-m water layers, all belonged to Flavobacteriales of the Bacteroidetes (p?<?0.05). In addition, bacterioplankton community richness and diversity at the continental shelf (CS) was generally higher than at oceanic stations (SB and KI). Five OTUs, which favored the habitat of continental shelf, belonged to Alphaproteobacteria including the orders of the SAR11 cluster, Rhodospirillales, Rhodobacterales and other unclassified orders (p?<?0.05). Two OTUs, which favored the habitat of oceanic stations, were assigned to the orders of Flavobacteriales and Alteromonadales. Furthermore, the abundances of two OTUs belonging to the Cyanobacteria phylum and Verrucomicrobiales order were significantly different between the sea basin (SB) and Kuroshio influenced area (KI) stations (p?<?0.05).     

pH effects on growth and lipid accumulation of the biofuel microalgae Nannochloropsis salina and invading organisms

Biofuels derived from non-crop sources, such as microalgae, offer their own advantages and limitations. Despite high growth rates and lipid accumulation, microalgae cultivation still requires more energy than it produces. Furthermore, invading organisms can lower efficiency of algae production. Simple environmental changes might be able to increase algae productivity while minimizing undesired organisms like competitive algae or predatory algae grazers. Microalgae are susceptible to pH changes. In many production systems, pH is kept below 8 by CO₂ addition. Here, we uncouple the effects of pH and CO₂ input, by using chemical pH buffers and investigate how pH influences Nannochloropsis salina growth and lipid accumulation as well as invading organisms. We used a wide range of pH levels (5, 6, 7, 8, 9, and 10). N. salina showed highest growth rates at pH 8 and 9 (0.19?±?0.008 and 0.19?±?0.011, respectively; mean ± SD). Maximum cell densities in these treatments were reached around 21 days into the experiment (95.6?×?10⁶?±?9?×?10⁶ cells mL^?1 for pH 8 and 92.8?×?10⁶?±?24?×?10⁶ cells mL^?1 for pH 9). Lipid accumulation of unbuffered controls were 21.8?±?5.8 % fatty acid methyl esters content by mass, and we were unable to trigger additional significant lipid accumulation by manipulating pH levels at the beginning of stationary phase. Ciliates (grazing predators) occurred in significant higher densities at pH 6 (56.9?±?39.6?×?10⁴ organisms mL^?1) than higher pH treatments (0.1–6.8?×?10⁴ organisms mL^?1). Furthermore, the addition of buffers themselves seemed to negatively impact diatoms (algal competitors). They were more abundant in an unbuffered control (12.7?±?5.1?×?10⁴ organisms mL^?1) than any of the pH treatments (3.6–4.7?×?10⁴ organisms mL^?1). In general, pH values of 8 to 9 might be most conducive to increasing algae production and minimizing invading organisms. CO₂ addition seems more valuable to algae as an inorganic carbon source and not as an essential mechanism to reduce pH.     

Development of an experimental laboratory fertilization protocol for the South African abalone,Haliotis midae (Linnaeus 1758)

In this study, effective gamete concentrations, egg viability, and fertilization volumes were evaluated for Haliotis midae (L.). Sperm concentrations between 5?×?10³ and 5?×?10⁴?mL^?1 (p?>?0.05) consistently resulted in high hatch-out rates (96?±?1%). At concentrations higher than 5?×?10⁵?mL^?1, hatch-out rates decreased to 69?±?7% (p??1 resulted in high fertilization rates, with 50?eggs?mL^?1 being the ideal concentration for fertilization in H. midae. Egg viability was consistently high up to 100?min post-spawning, with a decrease in hatch-out success, when eggs were fertilized 120?min post-spawning. Fertilization volumes did not affect successful hatch-out. The results from this study can be implemented by South African abalone farms to increase hatch-out rates and subsequent culture. It can also be used as basis for the development of fertilization protocols in other marine invertebrate species.     

Thiamine deficiency induces oxidative stress in brain mitochondria of Mus musculus

The present investigation evaluates the changes in the levels of antioxidant enzymes, lipid peroxidation (LPO), and protein carbonyl content (PCC) in brain mitochondria following thiamine deficiency (TD). The study was carried out on Mus musculus allocated into three groups, namely control and thiamine-deficient group for 8 (TD 8) and 10 (TD 10) days. The LPO was measured in terms of reduced glutathione (GSH) and thiobarbituric acid reactive substance (TBARS). Antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were measured biochemically. A significant increase in the TBARS (p?<?0.0001) and PCC (p?<?0.001) levels in group II (TD 8) and group III (TD 10) animals was observed in comparison to controls. The GSH levels were found to be reduced in both the treated groups compared to the control. A significant reduction in the activities of SOD was also observed in group II (p?<?0.01) and group III (p?<?0.0001) animals in comparison to the control. Enzymatic activities of CAT (p?<?0.001) and GPx (p?<?0.05) were found to be significantly reduced in group III (TD 10) in comparison to the control. In conclusion, reduction in the activities of antioxidant enzymes as well as an increase in LPO and PCC following TD implies oxidative stress in brain mitochondria that may further leads to neurodegeneration.     

Quantitative Mass Spectrometry Analysis Reveals that Deletion of the TRPV1 Receptor in Mice Alters Substance P and Neurokinin A Expression in the Central Nervous System

Vanilloid receptors have a central role in the processing of nociceptive stimuli. TRPV1 null mice showed significant decrease in response to heat noxious stimuli. However, thermal sensitivity is still present suggesting that the TRPV1 is not an exclusive transducer of thermal stimuli. Additionally, tachykinin peptides play a central role in pain processing and expression levels may also contribute in modifying the pain threshold. The LC?CMS/MS analysis revealed that SP and NKA were significantly down-regulated in TRPV1^?/? in spinal cord and brain tissues. In spinal cord, SP concentrations were 23.4?% lower (p?<?0.0049) and NKA concentrations were 22.0?% lower (p?<?0.0022) in TRPV1 null mice. Additionally, brain SP concentrations were 26.9?% lower (p?<?0.0260) and brain NKA concentrations were 31.9?% lower (p?<?0.0063) in TRPV1 null mice. These results clearly demonstrate that TPRV1 null mice exhibit lower SP and NKA concentrations in the central nervous system. The deficit of thermal responses may also be related to the down-regulations of SP and NKA.     

Effects of metalaxyl enantiomers stress on root activity and leaf antioxidant enzyme activities in tobacco seedlings

The objective of this experiment was to study the effects of metalaxyl enantiomers on the activity of roots and antioxidative enzymes in tobacco seedlings. Water culture experiment was conducted to analyze the effects of different concentrations of metalaxyl enantiomers (30 and 10 mg L^?1) on root activity and leaf superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities and malondialdehyde (MDA) content of tobacco seedlings. The results showed that metalaxyl significantly inhibited root activity and significantly improved leaf SOD, POD, and CAT activities and MDA content. A better physiological response in tobacco seedlings was observed at 30 mg L^?1 than at 10 mg L^?1 metalaxyl. The stereoselectivity for different enantiomers had no obvious effect on root activity and the leaf POD activity, but it affected significantly the SOD and CAT activities and MDA content. The SOD activity was promoted more by R‐enantiomer than by S‐enantiomer at 30 mg L^?1 metalaxyl, and the same effect was observed on CAT activity from the beginning to the end of the stress period. The MDA content under the stress by R‐enantiomer was higher than that under the stress by S‐enantiomer at 10 mg L^?1 metalaxyl.     

Effect of peroxynitrite on endothelial L-arginine transport and metabolism

Under conditions of oxidative stress it is well known that the bioavailability of nitric oxide (NO) is known to be significantly reduced. This process is in part due to the combination of NO with superoxide radicals to form peroxynitrite (ONOO^?). While this process inactivates NO per se, it is not certain to which extent this process may also further impair ongoing NO production. Given the pivotal role of arginine availability for NO synthesis we determined the impact of ONOO^? on endothelial arginine transport and intracellular arginine metabolism. Peroxynitrite reduced endothelial [³H]-l-arginine transport and increased the rate of arginine efflux in a concentration-dependent manner (both p < 0.05). In conjunction, exposure to ONOO^? significantly reduced the intracellular concentration of l-arginine, N^G-hydroxy-l-arginine (an intermediate of NO biosynthesis) and citrulline by 46%, 45% and 60% respectively (all p < 0.05), while asymmetric dimethyl arginine (ADMA) levels rose by 180% (p < 0.05). ONOO^? exposure did not alter the cellular distribution of the principal l-arginine transporter, CAT1, rather the effect on CAT1 activity appeared to be mediated by protein nitrosation. Conclusion Peroxynitrite negatively influences NO production by combined effects on arginine uptake and efflux, most likely due to a nitrosative action of ONOO^? on CAT-1.     

The Effects of Zinc Treatment on the Blood–Brain Barrier Permeability and Brain Element Levels During Convulsions

We evaluated the effect of zinc treatment on the blood–brain barrier (BBB) permeability and the levels of zinc (Zn), natrium (Na), magnesium (Mg), and copper (Cu) in the brain tissue during epileptic seizures. The Wistar albino rats were divided into four groups, each as follows: (1) control group, (2) pentylenetetrazole (PTZ) group: rats treated with PTZ to induce seizures, (3) Zn group: rats treated with ZnCl₂ added to drinking water for 2 months, and (4) Zn?+?PTZ group. The brains were divided into left, right hemispheres, and cerebellum?+?brain stem regions. Evans blue was used as BBB tracer. Element concentrations were analyzed by inductively coupled plasma optical emission spectroscopy. The BBB permeability has been found to be increased in all experimental groups (p?<?0.05). Zn concentrations in all brain regions in Zn-supplemented groups (p?<?0.05) showed an increase. BBB permeability and Zn level in cerebellum?+?brain stem region were significantly high compared to cerebral hemispheres (p?<?0.05). In all experimental groups, Cu concentration decreased, whereas Na concentrations showed an increase (p?<?0.05). Mg content in all the brain regions decreased in the Zn group and Zn?+?PTZ groups compared to other groups (p?<?0.001). We also found that all elements’ levels showed hemispheric differences in all groups. During convulsions, Zn treatment did not show any protective effect on BBB permeability. Chronic Zn treatment decreased Mg and Cu concentration and increased Na levels in the brain tissue. Our results indicated that Zn treatment showed proconvulsant activity and increased BBB permeability, possibly changing prooxidant/antioxidant balance and neuronal excitability during seizures.     

Leptin restores markers of female fertility in lipodystrophy

Objectives

Female reproductive dysfunction occurs in patients with pathological loss of adipose tissue, i.e. lipodystrophy (LD). However, mechanisms remain largely unclear and treatment effects of adipocyte-derived leptin have not been assessed in LD animals.