Introduction of a methoxymethyl side chain into p-phenylenediamine attenuates its sensitizing potency and reduces the risk of allergy induction

The strong sensitizing potencies of the most important primary intermediates of oxidative hair dyes, p-phenylenediamine (PPD) and p-toluylenediamine (PTD, i.e. 2-methyl-PPD) are well established. They are considered as the key sensitizers in hair dye allergic contact dermatitis. While modification of their molecular structure is expected to alter their sensitizing properties, it may also impair their color performance. With introduction of a methoxymethyl side chain we found the primary intermediate 2-methoxymethyl-p-phenylenediamine (ME-PPD) with excellent hair coloring performance but significantly reduced sensitizing properties compared to PPD and PTD: In vitro, ME-PPD showed an attenuated innate immune response when analyzed for its protein reactivity and dendritic cell activation potential. In vivo, the effective concentration of ME-PPD necessary to induce an immune response 3-fold above vehicle control (EC3 value) in the local lymph node assay (LLNA) was 4.3%, indicating a moderate skin sensitizing potency compared to values of 0.1 and 0.17% for PPD and PTD, respectively. Finally, assessing the skin sensitizing potency of ME-PPD under consumer hair dye usage conditions through a quantitative risk assessment (QRA) indicated an allergy induction risk negligible compared to PPD or PTD.     

Oxidative stress increased hepatotoxicity induced by nano‐titanium dioxide in BRL‐3A cells and Sprague–Dawley rats

Extensive studies have shown that titanium dioxide (TiO₂) nanomaterials (NMs) can cause toxicity in vitro and in vivo under normal conditions. However, an adverse effect induced by nano‐TiO₂ in many diseased conditions, typically characterized by oxidative stress (OS), remains unknown. We investigated the toxicity of nano‐TiO₂ in rat liver cells (BRL‐3A) and Sprague–Dawley (SD) rat livers under OS conditions, which were generated using hydrogen peroxide (H₂O₂) in vitro and alloxan in vivo, respectively. In vitro results showed that cell death ratios after nano‐TiO₂ exposure were significantly enhanced (up to 2.62‐fold) in BRL‐3A cells under OS conditions, compared with normal controls. Significant interactions between OS conditions and nano‐TiO₂ resulted in the rapid G0/G1 to S phase transition and G2/M arrest, which were opposite to G0/G1 phase arrest in cells after NMs exposure only. In vivo results showed that obvious pathological changes in rat livers and the increased activities of four enzymes (i.e. aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and alkaline phosphatase) owing to liver damage after nano‐TiO₂ exposure under OS conditions, compared with their healthy controls. In addition, compared with increased hepatotoxicity after nano‐TiO₂ exposure, micro‐TiO₂ showed no adverse effects to cells and rat livers under OS conditions. Our results suggested that OS conditions synergistically increase nano‐TiO₂ induced toxicity in vitro and in vivo, indicating that the evaluation of nanotoxicity under OS conditions is essentially needed prior to various applications of NMs in foods, cosmetics and potential treatment of diseases. Copyright © 2013 John Wiley & Sons, Ltd.     

Application of Hydrogen Peroxide to the Control of Eutrophic Lake Systems in Laboratory Assays

We exposed water samples from a recreational lake dominated by the cyanobacterium Planktothrix agardhii to different concentrations of hydrogen peroxide (H₂O₂). An addition of 0.33 mg·L⁻¹ of H₂O₂ was the lowest effective dose for the decay of chlorophyll-a concentration to half of the original in 14 h with light and 17 h in experiments without light. With 3.33 mg·L⁻¹ of H₂O₂, the values of the chemical oxygen demand (COD) decreased to half at 36 and 126 h in experiments performed with and without light, respectively. With increasing H₂O₂, there is a decrease in the total and faecal coliform, and this effect was made more pronounced by light. Total and faecal coliform were inhibited completely 48 h after addition of 3.33 mg·L⁻¹ H₂O₂. Although the densities of cyanobacterial cells exposed to H₂O₂ did not decrease, transmission electron microscope observation of the trichomes showed several stages of degeneration, and the cells were collapsed after 48 h of 3.33 mg·L⁻¹ of H₂O₂ addition in the presence of light. Our results demonstrate that H₂O₂ could be potentially used in hypertrophic systems because it not only collapses cyanobacterial cells and coliform bacteria but may also reduce chlorophyll-a content and chemical oxygen demand.     

过氧化氢低温等离子体灭菌器在儿科学器械灭菌中的应用

目的探讨过氧化氢低温等离子在儿科器械灭菌中的灭菌效果和失败原因的观察,为正确使用等离子灭菌器提供实践指导。方法对1264次使用过氧化氢等离子低温灭菌系统的情况进行监测。结果 1244次灭菌循环运行完成,20次循环被取消。结论过氧化氢等离子灭菌质量可靠、高效、环保。     

Nanomedicine for acute respiratory distress syndrome: The latest application,targeting strategy,and rational design

Acute respiratory distress syndrome (ARDS) is characterized by the severe inflammation and destruction of the lung air–blood barrier, leading to irreversible and substantial respiratory function damage. Patients with coronavirus disease 2019 (COVID-19) have been encountered with a high risk of ARDS, underscoring the urgency for exploiting effective therapy. However, proper medications for ARDS are still lacking due to poor pharmacokinetics, non-specific side effects, inability to surmount pulmonary barrier, and inadequate management of heterogeneity. The increased lung permeability in the pathological environment of ARDS may contribute to nanoparticle-mediated passive targeting delivery. Nanomedicine has demonstrated unique advantages in solving the dilemma of ARDS drug therapy, which can address the shortcomings and limitations of traditional anti-inflammatory or antioxidant drug treatment. Through passive, active, or physicochemical targeting, nanocarriers can interact with lung epithelium/endothelium and inflammatory cells to reverse abnormal changes and restore homeostasis of the pulmonary environment, thereby showing good therapeutic activity and reduced toxicity. This article reviews the latest applications of nanomedicine in pre-clinical ARDS therapy, highlights the strategies for targeted treatment of lung inflammation, presents the innovative drug delivery systems, and provides inspiration for strengthening the therapeutic effect of nanomedicine-based treatment.     

Blood-Brain Barrier Permeability of Asiaticoside,Madecassoside and Asiatic Acid in Porcine Brain Endothelial Cell Model

Neurotherapeutic potentials of Centella asiatica and its reputation to boost memory, prevent cognitive deficits and improve brain functions are widely acknowledged. The plant's bioactive compounds, i.e. asiaticoside, madecassoside and asiatic acid were reported to have central nervous system (CNS) actions, particularly in protecting the brain against neurodegenerative disorders. Hence, it is important for these compounds to cross the blood-brain barrier (BBB) to be clinically effective therapeutics. This study aimed to explore the capability of asiaticoside, madecassoside and asiatic acid to cross the BBB using in vitro BBB model from primary porcine brain endothelial cells (PBECs). Our findings showed that asiaticoside, madecassoside and asiatic acid are highly BBB permeable with apparent permeability (P_app) of 70.61 ± 6.60, 53.31 ± 12.55 and 50.94 ± 10.91 × 10^?6 cm/s respectively. No evidence of cytotoxicity and tight junction disruption of the PBECs were observed in the presence of these compounds. Asiatic acid showed cytoprotective effect towards the PBECs against oxidative stress. This study reported for the first time that Centella asiatica compounds demonstrated high capability to cross the BBB, comparable to central nervous system drugs, and therefore warrant further development as therapeutics for the treatment of neurodegenerative diseases.     

过氧化氢氧化降解法制备低分子玻璃酸

目的制备低分子玻璃酸 (HA)。方法过氧化氢氧化降解法。结果随着过氧化氢浓度增加 ,反应温度的升高 ,降解速率加快。中性条件下HA的氧化降解速率较快 ,而酸性或碱性时却较慢。为了方便降解过程的可控性 ,过氧化氢浓度选 0 .0 5 % ,反应温度定为 5 0℃ ,反应pH为中性。随着HA相对分子质量的降低 ,运动黏度迅速下降 ,而糖醛酸含量基本不变。不同过氧化氢浓度降解时 ,低分子HA收率基本相同。结论过氧化氢氧化降解法可用于制备低分子HA。     

刺五加叶皂甙对糖尿病大鼠脂质过氧化物的作用

目的 :探讨刺五加叶皂甙 (ASS)治疗糖尿病的作用机制。方法 :观察刺五加叶皂甙对四氧嘧啶实验性糖尿病大鼠血糖水平以及脂质过氧化物 (L PO)含量作用。对正常对照组、糖尿病对照组和喂饲刺五加叶皂甙组大鼠体内的上述指标进行检测。结果 :刺五加叶皂甙组大鼠血糖水平明显低于糖尿病对照组 (P <0 .0 1) ;血浆、胰腺 L PO含量显著低于糖尿病对照组(P<0 .0 5 ) ;超氧化物歧化酶 (SOD)活性在肝、胰腺明显高于糖尿病对照组 (P <0 .0 5 )。结论 :刺五加叶皂甙具有降低实验性糖尿病大鼠血糖的作用 ,其与提高抗氧自由基酶类活性及抗过氧化损伤有密切关系     

过氧化苯甲酰对小鼠肝脏组织损伤作用

目的 探讨面粉增白剂过氧化苯甲酰(benzoyl peroxide,BPO)对小鼠肝脏组织的损伤作用。方法 64只昆明种小鼠随机分为对照组和低、中、高剂量BPO组,分别灌胃给予BPO 50,100和200 mg/kg,每组16只,雌雄各半;灌胃6周后,测定各组肝脏组织中谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量及三磷酸腺苷(ATP)酶活力。结果 高、中剂量BPO组SOD活力分别为(40.15±7.13),(46.01±6.69)U/(mg·prot),与对照组(53.15±6.55)U/(mg·prot)比较,差异有统计学意义(P<0.05);高剂量BPO组与对照组MDA含量分别为(1.93±0.37)和(1.57±0.33)nmol/(mg·prot),差异有统计学意义(P<0.05);高剂量BPO组Mg²⁺-ATP、Ca²⁺-ATP酶活力分别为(1.58±0.11)和(1.48±0.09)μmol Pi/(mg·prot),与对照组比较明显降低,差异有统计学意义(P<0.05);各剂量BPO组GSH-Px活力与对照组比较差异无统计学意义(P>0.05)。结论 BPO在一定程度上可降低小鼠肝脏抗氧化及Ca²⁺、Mg²⁺-ATP酶活力。     

用正交法探讨过氧乙酸含量测定的影响因素

目的探讨过氧乙酸含量测定的影响因素.方法用正交法设计影响因素,碘量法测定其含量.结果高锰酸钾放置时间是影响过氧乙酸含量测定的主要因素.结论当滴加高锰酸钾液使供试液呈微红色时应迅速地完成实验操作.