Effect of synthetic antioxidants on hydrogen peroxide formation, oxyferro cytochrome P-450 concentration and oxygen consumption in liver microsomes

Synthetic antioxidants lead in vitro to increased H2O2 formation in rat liver and lung microsomes and in guinea pig and hamster liver microsomes. Butylated hydroxyanisole and ethoxyquin are more potent than propyl-, octyl-, and dodecyl gallate; butylated hydroxytoluene is only weakly active. Extra production of H2O2 is maximal at antioxidant concentrations between 50 and 500 microM and is dependent on the concentration of NADPH. It is paralleled by increased microsomal oxygen consumption and decreased concentration of oxycytochrome P-450 and is enhanced by pretreatment of the animals with phenobarbital. Both the endogenous and the antioxidant-stimulated H2O2 production are inhibited by metyrapone. In vivo administration of ethoxyquin and butylated hydroxyanisole in the diet leads to decreased oxycytochrome P-450 concentrations but not to increased H2O2 formation in liver microsomes. No extra production of H2O2 was observed in a glucose oxidase or xanthine oxidase system; rather, inhibition occurred in the latter system. Our data suggest that antioxidants enhance the oxidase function of cytochrome P-450. This effect is discussed in view of the known toxicity of these food additives.     

对-羟基苯甲酸丁酯对人精子顶体蛋白酶的抑制作用及其对精子膜功能的影响

本文用明胶玻片法研究对-羟基苯甲酸丁酯对人类精子顶体蛋白酶水解活性的抑制作用,较典型的顶体蛋白酶抑制剂TLCK 的抑制活性强20倍。应用精子尾低渗膨胀实验方法和曙红染色方法,还证明了对-羟基苯甲酸丁酯对精子膜功能有破坏作用;用不同浓度的对-羟基苯甲酸丁酯处理精子1min 后,精子尾低渗膨胀百分率与存活精子百分率具有很好的正相关性(r=0.92)。这说明此化合物的杀精子作用可能是由于对精子膜功能的损伤所致。由于这种化合物能够强烈地抑制人类精子顶体蛋白酶的蛋白水解活性。并对精子膜功能产生不可逆转的损伤,所以很有希望开发成为新型的阴道避孕药。     

Tris (1,3‐dichloro‐2‐propyl) phosphate induces toxicity by stimulating CaMK2 in PC12 cells

Tris (1,3‐dichloro‐2‐propyl) phosphate (TDCIPP) is one of the widely used organophosphorus flame retardants (OPFRs), which are regarded as suitable substitutes for brominated flame retardants (BFRs). Previously, we have validated the toxicity of TDCIPP in PC12 cells owing to the induced alterations in GAP43, NF‐H, CaMK2a/2b, and tubulin α/β proteins; however, limited information is currently available on the toxicity and mechanism of TDCIPP. In the present study, cytotoxicity effects were evaluated by exposing PC12 cells to different concentrations of TDCIPP (0–50 μM) for 4 days. To explore the possible mechanisms through which cytotoxicity is induced, changes in intracellular [Ca²⁺]_i levels and the activation of calmodulin dependent protein kinase 2 (CaMK2), c‐Jun N‐terminal kinase (JNK), extracellular regulated protein kinases (ERK1/2), and p38 mitogen‐activated protein kinases (MAPK) pathways were evaluated. Furthermore, PC12 cells were pretreated with CaMK2 inhibitor KN93 to investigate the relationship between TDCIPP‐induced phosphorylation of CaMK2 and activation of JNK, ERK1/2, and p38 MAPK pathways. Our results indicate that TDCIPP‐induced toxicity might be associated with the overload of [Ca²⁺]_i levels, increased phosphorylation of CaMK2, and activation of the JNK, ERK1/2, and p38 MAPK pathways, the lattermost of which was further demonstrated to be partially elicited by the CaMK2 phosphorylation.     

Novel approach for real-time monitoring of carrier-based DPIs delivery process via pulmonary route based on modular modified Sympatec HELOS

An explicit illustration of pulmonary delivery processes (PDPs) was a prerequisite for the formulation design and optimization of carrier-based DPIs. However, the current evaluation approaches for DPIs could not provide precise investigation of each PDP separately, or the approaches merely used a simplified and idealized model. In the present study, a novel modular modified Sympatec HELOS (MMSH) was developed to fully investigate the mechanism of each PDP separately in real-time. An inhaler device, artificial throat and pre-separator were separately integrated with a Sympatec HELOS. The dispersion and fluidization, transportation, detachment and deposition processes of pulmonary delivery for model DPIs were explored under different flow rates. Moreover, time-sliced measurements were used to monitor the PDPs in real-time. The Next Generation Impactor (NGI) was applied to determine the aerosolization performance of the model DPIs. The release profiles of the drug particles, drug aggregations and carriers were obtained by MMSH in real-time. Each PDP of the DPIs was analyzed in detail. Moreover, a positive correlation was established between the total release amount of drug particles and the fine particle fraction (FPF) values (R² = 0.9898). The innovative MMSH was successfully developed and was capable of illustrating the PDPs and the mechanism of carrier-based DPIs, providing a theoretical basis for the design and optimization of carrier-based DPIs.     

RP-HPLC法测定注射用棓丙酯的含量及有关物质

目的:建立注射用棓丙酯含量和有关物质的RP-HPLC测定方法。方法:采用Agilent SB C18(150 mm×4.6 mm,5μm)色谱柱,以pH2.51的磷酸盐缓冲液-甲醇(6∶4)为流动相,流速1 mL.min-1,检测波长274 nm,柱温25℃。结果:棓丙酯主要成分峰与其相关物质峰完全分离,棓丙酯浓度在5～30μg.mL-1范围内呈良好线性关系,最低检测限(S/N≥3)为2.5 ng.mL-1。结论:该方法专属性好,精密度、稳定性符合要求,方法可靠,可用于棓丙酯含量及其有关物质的测定。     

氨酚氢可酮口服溶液中4种成分的HPLC测定

目的:建立 HPLC 法同时测定氨酚氢可酮口服溶液中主成分(对乙酰氨基酚、重酒石酸氢可酮)和防腐剂(对羟基苯甲酸甲酯、对羟基苯甲酸丙酯)的含量。方法:采用 Zorbax SB-C_(18)柱(4.6 mm×250 mm,5 μm);以0.025 mol·L~(-1)乙酸胺溶液(用冰醋酸调 pH 至4.0)-乙腈(19:81)为流动相 A,0.025 mol·L~(-1)乙酸胺溶液(用冰醋酸调 pH 至4.0)-乙腈(75:25)为流动相 B 进行梯度洗脱;流速为1.0 mL·min~(-1);柱温为35℃;检测波长为280 nm(对乙酰氨基酚)、214 nm(重酒石酸氢可酮)和257 nm(对羟基苯甲酸甲酯和对羟基苯甲酸丙酯)。结果:对乙酰氨基酚、重酒石酸氢可酮、对羟基苯甲酸甲酯和对羟基苯甲酸丙酯的线性范围分别为133.4～1668,2.272～28.40,7.278～90.97,0.7960～9.950μg·mL~(-1);加样回收率(n=9)分别为98.6%,103.7%,100.2%,103.5%。结论:方法简便、准确,可用于氨酚氢可酮口服溶液中4种成分的同时测定。     

Direct and indirect 5-HT receptor agonists produce gender-specific effects on locomotor and vertical activities in C57 BL/6J mice

It is well established that the dopamine (DA) and serotonin (5-HT) systems have extensive and complex interactions. However, the effects of specific 5-HT receptor agonists on traditionally DA-related behaviors remain unclear. Our goal in these studies was to characterize the effects of 5-HT receptor agonists on measures of locomotor activity and vertical rearing. The SSRIs fluoxetine and citalopram produced significant decreases in locomotor activity and vertical rearing at the highest doses used with females significantly more sensitive to citalopram. The 5-HT_1A agonist 8-OH-DPAT and the 5-HT_2C agonist MK 212 significantly decreased activity in both male and female mice, with females more sensitive to 8-OH-DPAT. In contrast, the 5-HT_1B agonist RU 24969 and the 5-HT_2A agonist DOI both increased activity, with DOI exhibiting differential effects with regard to sex. Finally, the 5-HT₃ agonist SR 57227 produced significant locomotor increases only in female mice at the lowest dose. The results of these experiments define locomotor profiles of several 5-HT agonists in male and female C57BL/6J mice, providing a foundation for further explorations of 5-HT receptor effects on activity.     

Development and applications of photo-triggered theranostic agents

Theranostics, the fusion of therapy and diagnostics for optimizing efficacy and safety of therapeutic regimes, is a growing field that is paving the way towards the goal of personalized medicine for the benefit of patients. The use of light as a remote-activation mechanism for drug delivery has received increased attention due to its advantages in highly specific spatial and temporal control of compound release. Photo-triggered theranostic constructs could facilitate an entirely new category of clinical solutions which permit early recognition of the disease by enhancing contrast in various imaging modalities followed by the tailored guidance of therapy. Finally, such theranostic agents could aid imaging modalities in monitoring response to therapy. This article reviews recent developments in the use of light-triggered theranostic agents for simultaneous imaging and photoactivation of therapeutic agents. Specifically, we discuss recent developments in the use of theranostic agents for photodynamic-, photothermal- or photo-triggered chemotherapy for several diseases.     

Aspirin response evaluated by the VerifyNow Aspirin System and light transmission aggregometry

Introduction

Patients with inadequate platelet inhibition by aspirin, referred to as aspirin resistance, might have an increased risk of suffering cardiovascular events. Therefore, identification of these patients by measuring platelet function is of great interest. Our objectives were to evaluate performance parameters of VerifyNow™ and to determine the agreement between VerifyNow™ and light transmission aggregometry (LTA) ad modum Born.

Materials and Methods

We included 21 healthy volunteers and 40 patients with stable coronary artery disease. Duplicate measurements of platelet aggregation were performed using VerifyNow™ and LTA (arachidonic acid 1.0 mM) in healthy volunteers before aspirin and in all participants on four consecutive days during treatment with non-enteric-coated aspirin 75 mg daily. VerifyNow™ test results were expressed in Aspirin Reaction Units (ARU) and LTA test results in percent of maximal aggregation. The cut-off for determination of aspirin resistance was ≥ 550 ARU and ≥ 20%, respectively.

Results

All participants were compliant, confirmed by complete suppression of serum-thromboxane B₂. VerifyNow™ was highly repeatable with a coefficient of variance of 0.5% at baseline and 3.0% during aspirin treatment. No individuals were identified as aspirin resistant with VerifyNow™, whereas seven (12%) individuals were identified with LTA. ROC analysis using LTA as the gold standard showed poor sensitivity and good specificity with a cut-off at 550 ARU.

Conclusion

VerifyNow™ was highly repeatable, but further studies are needed to investigate the relevance of the cut-off level at 550 ARU for detecting aspirin resistance.