Reactive Oxygen Species Are Essential for Vasoconstriction upon Cold Exposure

Purpose. We explored the role of ROS in cold-induced vasoconstriction and corresponding mechanism. Methods. Three experiments were performed. First, we measured blood flow in human hands before and after cold exposure. Second, 24 mice were randomly divided into 3 groups: 8 mice received saline injection, 8 received subcutaneous Tempol injection, and 8 received intrathecal Tempol injection. After 30 min, we determined blood flow in the skin before and after cold exposure. Finally, we used Tempol, CCG-1423, and Go 6983 to pretreat HAVSMCs and HUVECs for 24 h. Then, cells in the corresponding groups were exposed to cold (6 h, 4°C). After cold exposure, the cytoskeleton was stained. Intracellular Ca2+ and ROS levels were measured by flow cytometry and fluorescence microscopy. We measured protein expression via Western blotting. Results. In the first experiment, after cold exposure, maximum skin blood flow decreased to 118.4 ± 50.97 flux units. Then, Tempol or normal saline pretreatment did not change skin blood flow. Unlike intrathecal Tempol injection, subcutaneous Tempol injection increased skin blood flow after cold exposure. Finally, cold exposure for 6 h shrank the cells, making them narrower, and increased intracellular Ca2+ and ROS levels in HUVECs and HAVSMCs. Tempol reduced cell shrinkage and decreased intracellular Ca2+ levels. In addition, Tempol decreased intracellular ROS levels. Cold exposure increased RhoA, Rock1, p-MLC-2, ET-1, iNOS, and p-PKC expression and decreased eNOS expression. Tempol or CCG-1423 pretreatment decreased RhoA, Rock1, and p-MLC-2 levels in HAVSMCs. Furthermore, Tempol or Go 6983 pretreatment decreased ET-1, iNOS, and p-PKC expression and increased eNOS expression in HUVECs. Conclusion. ROS mediate the vasoconstrictor response within the cold-induced vascular response, and ROS in blood vessel tissues rather than nerve fibers are involved in vasoconstriction via the ROS/RhoA/ROCK1 and ROS/PKC/ET-1 pathways in VSMCs and endothelial cells.

N-acetylcysteine alleviates PCB52-induced hepatotoxicity by repressing oxidative stress and inflammatory responses

Polychlorinated biphenyls (PCBs), particularly low chlorinated congeners in our environment, can induce human hepatotoxicity. However, the mechanisms by which PCBs cause hepatotoxicity remain elusive. Moreover, there are no effective treatments for this condition. In this study, 40 μM PCB52 was administered to rat (Brl-3A) and human hepatocytes (L-02) for 48 h following the N-acetylcysteine (NAC)/saline pretreatment. A significant decrease in cell viability was observed in PCB52-treated cells relative to the control. Besides, PCB52 significantly increased reactive oxygen species (ROS) levels and malondialdehyde (MDA) contents, suggesting induction of oxidative stress. The expression of Traf6, MyD88, and Tnf in Brl-3A cells and that of MYD88, TNF, and IL1B in L-02 cells were significantly upregulated by PCB52. Consistently, overexpression of TLR4, MyD88, Traf6, and NF-κB p65 proteins was observed in PCB52-treated cells, indicating activation of inflammatory responses. Nevertheless, no changes in kelch-like ECH-associated protein 1 (keap1), nuclear factor-erythroid 2-related factor (nrf2), and heme oxygenase-1 proteins were observed in PCB52-treated cells, indicating non-activation of the keap1/nrf2 pathway. Pretreatment with NAC significantly ameliorated PCB52 effects on cell viability, ROS levels, MDA contents and expression of inflammatory elements at both RNA and protein levels. However, no changes in keap1, nrf2 and HO-1 protein levels were detected following NAC pretreatment. Taken together, with non-activated keap1/nrf2 pathway, PCB52-induced oxidative stress and inflammatory responses could be responsible for its hepatotoxicity. These effects were effectively attenuated by NAC pretreatment, which scavenges ROS and dampens inflammatory responses. This study might provide novel strategies for the treatment of the PCBs-associated hepatotoxic effects.

Lidocaine Versus Ketamine Pretreatment on Propofol Injection Pain

Propofol is commonly used intravenous anesthesia induction drug but it causes ache upon use, many methods with different results, have been suggested to prevent this pain, the current research was concluded in order to investigate the impact of lidocaine, ketamine in reducing the ache on giving intravenous propofol. This study is randomized controlled clinical trial lasting from June 2015 to November 2015 during which 107 consenting (ASA1 and ASA2) patients were prepared for elective operation with general anesthesia. They randomly split to three subgroups, A cannula (size20) used in the dorsum hand veins, standard monitor was established patients received either 2mL (40 mg) of lidocaine or 2mL (20mg) of ketamine and 2 mL of saline 1 min before injection 2.5 milligram per kilogram propofol. ache severity observed by using four number pain scale, zero = none, one= mild pain, two = moderate pain, and three = intense pain. Atracurium used for indotracheal intubation, isoflurane and fentanyl for anesthesia maintenance. There were no variations between the study groups regarding ASA status, Sex, age. The incidence of ache when injecting propofol were observed in the normal saline group was 86.5% and it was more than ketamine group 0% and lidocaine group 20% (p=0.0002). In the normal saline pretreatment group 8.1% of the patient experienced severe pain, compared with 0% in the lidocaine and ketamine. It can be concluded that intravenous ketamine and lidocaine were equally effective in preventing Ache during propofol injection.

Lacosamide Reduces Seizure Severity but Increases Seizure Frequency in PTZ-Kindled Rats

Objective: This study evaluated the anticonvulsant action of lacosamide (LCS), a novel drug that was recently approved for the treatment of partial or secondarily generalized seizures, using an animal model of generalized epilepsy induced by repetitive pentylenetetrazole (PTZ) administration in rats. The main goal was to evaluate the behavioral pattern of lacosamide action by classifying seizures according to a modi Racine-scale. Furthermore, the reproducibility of the win-PTZ kindling model of epilepsy, a recently described variant of the standard PTZ-kindling model, was also assessed.Methods: Adult male Wistar rats (n=16) were divided into two groups and underwent the win-PTZ-kindling protocol in two independent trials. After finishing the kindling procedure, all animals, which presented stage 5 seizures were tested for the anticonvulsant action of lacosamide at three different doses (3, 10, and 30 mg/kg).Results: The maximal severity of seizures decreased and the latency to stage 3-5 seizures increased when the animals were treated with lacosamide at a single dose of 10 mg/kg compared to saline pretreatment (p < 0.05), both parameter reflecting an anticonvulsant action of the drug. Unfortunately, the number of stage 3-5 seizures also increased, but not significantly. The win-PTZ kindling model showed an adequate reproducibility between different trials, however, the number of fully kindled rats was lower than previously reported.Conclusions: Lacosamide showed a convincing anticonvulsant action in the win-PTZ kindling model of epilepsy by preventing the generalization of seizures. The win-PTZ kindling model was proved to be useful for studying epileptogenesis and the anticonvulsant action of drugs.

Superoxide dismutase failed to attenuate allergen-induced nasal congestion in ragweed-sensitized dogs

We hypothesized that augmentation of antioxidant defenses with exogenous superoxide dismutase (SOD), an enzyme that provides an initial defense against oxidative injury, would attenuate allergen-induced nasal congestion in the canine model of allergic rhinitis. Nasal congestion was evaluated by the measurements of nasal resistance and the volume of the nasal passage. In five nonsensitized dogs, 30,000 U of SOD from bovine erythrocytes delivered by aerosol to the nasal passages before histamine challenge reduced the histamine-induced nasal congestion. At 30 min postchallenge, nasal resistance was 1.14 ± 0.2 cmH2O·l−1·min−1 in the saline pretreatment study vs. 0.36 ± 0.02 cmH2O·l−1·min−1 in the SOD pretreatment study ( P < 0.05), and volume of nasal passage was 10.9 ± 0.5 cm3 vs. 17.4 ± 1.3 cm3 ( P < 0.05), respectively. In five sensitized dogs, however, neither an analogous pretreatment with SOD nor intranasal aerosolized pretreatment with 30,000 U of SOD conjugated to polyethylene glycol attenuated ragweed-induced nasal congestion. Also, systemic application of SOD did not attenuate responses to challenges with histamine and ragweed in nonsensitized and sensitized dogs, respectively. The antioxidant-induced attenuation of nasal congestion in nonsensitized dogs confirms validity of the model and indicates the involvement of free radical-mediated damage in the genesis of the histamine-induced congestion. In sensitized dogs, the data do not support the hypothesis that oxidative stress is a clinically significant component of acute ragweed-induced nasal congestion. The data do not support the use of SOD for acute protection against allergic rhinitis.

Central angiotensin AT1 and muscarinic receptors in ITF expression on intracerebroventricular NaCl

In the present study, we investigated the expression pattern of the inducible transcription factors (ITF) c-Fos, c-Jun, JunB, JunD, and Krox-24 following intracerebroventricular injections of hyperosmolar saline (0.2, 0.3, and 0.6 M NaCl) and its mediation via angiotensin and/or muscarinic receptors. c-Fos, c-Jun, and Krox-24 were differentially expressed in organum vasculosum laminae terminalis, median preoptic area, subfornical organ (SFO), and paraventricular and supraoptic nuclei. Expression of c-Fos and c-Jun was inhibited by pretreatment with the angiotensin AT1 receptor antagonist losartan (10 and 20 nmol icv) following 0.20 and 0.30 M saline. Pretreatment with atropine (15 nmol icv) inhibited the 0.30 and 0.60 M NaCl-induced expression of c-Fos, c-Jun, and Krox-24 in all areas except the SFO. Coexpression of the ITF with vasopressin and oxytocin, the major effector peptides in osmoregulation, was demonstrated, implying the corresponding genes as putative target genes of the ITF. The results show a highly differentiated ITF expression pattern in the brain mediated by angiotensinergic and muscarinergic pathways, suggesting a finely tuned regulation of target genes.

Light microscopic observations of Echinostoma caproni metacercariae during in vitro excystation

Light microscopy was used to study excystation of Echinostoma caproni metacercariae in various media. Optimal excystation was observed in an alkaline trypsin-bile salts medium (TB) at 40 ± 1°C. The percentage of excystation in TB medium declined following either acid pepsin or acid saline pretreatment. Excystation rarely occurred in either trypsin or bile salts alone. Dissolution of the outer cyst occurred in TB medium thus facilitating excystation. Activation of the larva within the inner cyst led to its eventual release through an aperture in the mucoid plug region. Excystation of this species was facilitated by both intrinsic and extrinsic factors. There were considerable differences in excystation events between this species and the related allopatric species, E. trivolvis

By 94 days of gestation plasma cortisol increases block ACTH response to hypotension in lamb fetuses

By use of a crossover design, we studied the effects of increasing plasma cortisol concentration on ACTH responses to a standardized stress in 14 lamb fetuses between 94 and 108 days gestation. On a random basis we assigned the animals into two groups of seven. Animals in groups I and II received infusions of cortisol (5 and 1 microgram/min, respectively) or saline for 4 h. After the cortisol or saline pretreatment, we reduced arterial pressure approximately 40-50% in both groups of animals with nitroprusside. After saline pretreatment, hypotension in the group I animals produced an increase in the fetal plasma ACTH from 15 +/- 3 to 200 +/- 20 pg/ml (P less than 0.001), and in the group II animals pretreated with saline plasma ACTH increased from 21 +/- 4 to 141 +/- 19 pg/ml (P less than 0.001) with hypotension. Cortisol pretreatment elevated fetal plasma cortisol levels from 7 +/- 3 to 36 +/- 5 ng/ml in group I and from 8 +/- 4 to 20 +/- 2 ng/ml in group II. The ACTH response to hypotension in both groups was abolished by the cortisol pretreatment. We conclude that by 94 days gestation increases in plasma cortisol within a physiological range block ACTH responses to hypotension in lamb fetuses.