新月菱形藻胞外多糖的成分及其硫酸酯的制备

目的阐明新月菱形藻胞外多糖(exopolysaccharides of Nitzschia closterium,EPN)的成分、单糖组成及其硫酸酯化条件。方法新月菱形藻胞外多糖以醇沉法从该藻的培养液中制备;DEAE-Sephedex25柱分离,HPLC法测定其质量分数,HPLC测定其相对分子质量;以氯磺酸-吡啶法探索新月菱形藻硫酸酯化反应条件。结果新月菱形藻向胞外分泌3种多糖,相对分子质量分别为EPN11.886×105,EPN21.41×105,EPN31.134×105。3种多糖的单糖组成均为甘露糖、鼠李糖、葡萄糖醛酸、葡萄糖和岩藻糖。甘露糖、鼠李糖、葡萄糖醛酸、葡萄糖和岩藻糖的摩尔比在EPN1为4.3∶1∶5.1∶8.9∶5.6,EPN2为4.2∶7.3∶3.7∶12.8∶3.4,EPN3为3.5∶2.1∶4.3∶4.9∶4.7。3种多糖的硫酸酯化条件基本一致,提高氯磺酸比例和延长反应时间均有利于增加酯化产物的硫酸根、提高取代度和酸酯化反应的产率。结论新月菱形藻胞外多糖为酸性多糖,其硫酸酯化产物多糖硫酸酯可能具有潜在的药理活性。     

人胚胎RPE细胞在微孔聚酰胺纳米纤维膜和蚀刻多孔聚酯膜上生长的比较研究

目的: 比较观察人胚胎视网膜色素上皮(RPE)细胞在微孔聚酰胺纳米纤维膜(EPN)和蚀刻多孔聚酯膜(EPP)上的生长情况,为理想Bruch’s 膜替代物的研究奠定实验基础。方法: 人胚胎RPE细胞培养在底分别为EPN(EPN组)、EPP(EPP组)的Transwell 小室以及常规Transwell小室(对照组)。在第2,4,8 h和第1,4,8天分别评估3组细胞的贴壁和增殖情况。对比观察细胞生长形态及两种替代物的表面结构;免疫荧光染色观察RPE细胞ZO-1的表达。通过组织病理切片观察EPN和EPP植入21天龄(P21) RCS大鼠视网膜下间隙2周后的生物学反应。结果: 接种8 h(密度为4×10⁵/cm²)后,EPN组, EPP组和对照组RPE细胞贴壁生长数量分别为1.23×10⁵/cm²,1.70×10⁵/cm²和1.64×10⁵/cm²,其中EPN组细胞数量明显少于EPP组及对照组(P<0.05);以2.5×10⁵/cm²的密度接种后第1天,EPN组细胞密度明显低于EPP组和对照组(P<0.05),但在接种后第8天,EPN组细胞数量显著多于EPP组和对照组(P<0.05)。EPN 和EPP均支持RPE 单细胞层形成,前者纤维排列类似Bruch’s 膜内胶原层;与对照组比,EPN和EPP组RPE细胞均呈现较强的ZO-1表达,较好地保持了原代RPE细胞表型;EPP和EPN植入视网膜下间隙后出现纤维包裹和光感受器层破坏、丢失,但在移植物附近未见明显毒性或排斥等其他异常反应。结论: EPN和EPP均支持人胚胎RPE细胞生长,二者植入P21 RCS大鼠视网膜下间隙后存在大体生物相容性。EPN的纤维排列与Bruch’s膜内胶原层相近,可能是一种具有广阔发展前途的Bruch’s 膜替代物。     

Induction of xenobiotic metabolism in rats by short-term administration of brominated diphenyl ethers

Commercial preparations of fire retardant brominated diphenyl ethers were tested along with bis (-bromophenyl) ether and diphenyl ether for their ability to alter xenobiotic metabolism. The materials, 0.1 $\text{mmol}\text{kg}\text{day}$, were administered p.o. to male rats for 14 days. Pentabromodiphenyl and octa-bromodiphenyl ether preparations increased O-ethyl O-p-nitrophenyl phenyl-phosphonothioate (EPN) detoxification, p-nitroanisole demethylation, NADPH-cytochrome c reductase, cytochrome P-450, liver weight, UDP-glucuronyltrans-ferase and benzo[a] pyrene hydroxylase. Diphenyl ether increased only EPN detoxification and decabromodiphenyl ether only liver weight. Bis(p-bromo-phenyl) ether increased liver weight, cytochrome c reductase and cytochrome P-450. The data indicate that these materials are inducers of xenobiotic metabolism with activity dependent upon degree of bromination.     

新月菱形藻胞外多糖的成分及其硫酸酯的制备

目的阐明新月菱形藻胞外多糖(exopolysaccharides of Nitzschia closterium,EPN)的成分、单糖组成及其硫酸酯化条件。方法新月菱形藻胞外多糖以醇沉法从该藻的培养液中制备;DEAE-Sephedex25柱分离,HPLC法测定其质量分数,HPLC测定其相对分子质量;以氯磺酸-吡啶法探索新月菱形藻硫酸酯化反应条件。结果新月菱形藻向胞外分泌3种多糖,相对分子质量分别为EPN11.886×105,EPN21.41×105,EPN31.134×105。3种多糖的单糖组成均为甘露糖、鼠李糖、葡萄糖醛酸、葡萄糖和岩藻糖。甘露糖、鼠李糖、葡萄糖醛酸、葡萄糖和岩藻糖的摩尔比在EPN1为4.3∶1∶5.1∶8.9∶5.6,EPN2为4.2∶7.3∶3.7∶12.8∶3.4,EPN3为3.5∶2.1∶4.3∶4.9∶4.7。3种多糖的硫酸酯化条件基本一致,提高氯磺酸比例和延长反应时间均有利于增加酯化产物的硫酸根、提高取代度和酸酯化反应的产率。结论新月菱形藻胞外多糖为酸性多糖,其硫酸酯化产物多糖硫酸酯可能具有潜在的药理活性。     

A near-fatal case of emphysematous pyelonephritis: Embracing the new management ‘gold standard’ – Saving the life while saving the kidney!

Introduction

Emphysematous pyelonephritis (EPN) is a rare, acute, severe infection of the renal parenchyma and its surrounding tissues and is associated with a significant morbidity and mortality. Underlying diabetes is the most commonly associated risk factor.

Early cortical processing of natural and artificial emotional faces differs between lower and higher socially anxious persons

Emotional facial expressions provide critical information for social interactions. Above all, angry faces are assumed to reflect potential social threat. We investigated event-related potentials (ERPs) triggered by natural and artificial faces expressing fear, anger, happiness or no emotion in participants with low and high levels of social anxiety. Overall, artificial faces elicited stronger P100 and N170 responses than natural faces. Additionally, the N170 component was larger for emotional compared to neutral facial expressions. Social anxiety was associated with an enhanced emotional modulation of the early posterior negativity (EPN) in response to fearful and angry facial expressions. Additionally, while the late positive potential (LPP) was larger for emotional than for neutral faces in low socially anxious participants, LPPs of higher socially anxious participants did not differ. LPPs might therefore be enhanced in higher socially anxious participants for both emotional and neutral faces. Furthermore, the modulations of the EPN and LPP were comparable between natural and artificial faces. These results indicate that social anxiety influences early perceptual processing of faces and that artificial faces are suitable for psychophysiological emotion research.

c-Fos expression after deep brain stimulation of the pedunculopontine tegmental nucleus in the rat 6-hydroxydopamine Parkinson model

Deep brain stimulation (DBS) is used to alleviate motor dysfunction in Parkinson's disease (PD). The pedunculopontine nucleus (PPN) may be a potential target for severe freezing and postural instability with 25 Hz stimulation being considered more effective than 130 Hz stimulation. Here we evaluated the expression of c-Fos after 25 Hz and 130 Hz DBS of the pedunculopontine tegmental nucleus (PPTg, i.e., the rodent equivalent to the human PPN) in the rat 6-hydroxydopamine (6-OHDA) PD model.Anaesthetized male Sprague Dawley rats with unilateral 6-OHDA-induced nigrostriatal lesions were stimulated with 25 Hz, 130 Hz, or 0 Hz sham-stimulation for 4 h by electrodes implanted into the ipsilateral PPTg. Thereafter the distribution and number of neurons expressing the immediate early gene c-Fos, a marker for acute neuronal activity, was assessed.DBS of the PPTg induced strong ipsilateral c-Fos expression at the stimulation site, with 25 Hz having a more marked impact than 130 Hz. Additionally, c-Fos was strongly expressed in the central gray. In the dorsal part expression was stronger after 25 Hz stimulation, while in the medial and ventral part there was no difference between 25 Hz and 130 Hz stimulation. Expression in the basal ganglia was negligible.In the rat 6-OHDA PD model stimulation of the PPTg did not affect c-Fos expression in the basal ganglia, but had a strong impact on other functional circuitries. PPN stimulation in humans might therefore also have an impact on other systems than the motor system.     

Explicit semantic stimulus categorization interferes with implicit emotion processing

Previous functional magnetic resonance imaging and event-related brain potential studies revealed that performing a cognitive task may suppress the preferential processing of emotional stimuli. However, these studies utilized simple and artificial tasks (i.e. letter, shape or orientation discrimination tasks), unfamiliar to the participants. The present event-related potential study examined the emotion–attention interaction in the context of a comparably more natural scene categorization task. Deciding whether a natural scene contains an animal or not is a familiar and meaningful task to the participants and presumed to require little attentional resources. The task images were presented centrally and were overlaid upon emotional or neutral background pictures. Thus, implicit emotion and explicit semantic categorization may compete for processing resources in neural regions implicated in object recognition. Additionally, participants passively viewed the same stimulus materials without the demand to categorize task images. Significant interactions between task condition and emotional picture valence were observed for the occipital negativity and late positive potential. In the passive viewing condition, emotional background images elicited an increased occipital negativity followed by an increased late positive potential. In contrast, during the animal-/non-animal-categorization task, emotional modulation effects were replaced by strong target categorization effects. These results suggest that explicit semantic categorization interferes with implicit emotion processing when both processes compete for shared resources.     

Disposition,elimination and metabolism of O-ethylO-4-nitrophenyl phenylphosphonothioate after subchronic dermal application in male cats

The metabolism, distribution, and excretion of the insecticide O-ethylO-4-nitrophenyl phenylphosphonothioate (EPN) were studied in the male cat. Each cat was given a daily dermal dose of 0.5 mg/kg [¹⁴C] EPN for 10 consecutive days. Fifteen days after the last dose, the cats had excreted 62% of the cumulative dose in the urine and 10% in the faces. No ¹⁴CO₂ was detected in the expired air. O-Ethyl phenylphosphonic acid (EPPA) was identified as the major urinary and fecal metabolite. Phenylphosphonic acid (PPA) was the second highest metabolite. Only traces of the intact EPN were recovered in the urine and feces. The disposition studies performed 1, 5, 10 and 15 days after the administration of the last dose showed that EPN was the major compound identified in the brain, spinal cord, sciatic nerve, adipose tissue, plasma and kidney. Most of the radioactivity in the liver was identified as EPPA followed by PPA. The time course of plasma EPN, determined after the 10th daily dose was biphasic. The slower process had a half-life of 17.0 days. After tissue distribution was completed, tissue elimination was adequately represented as a single first-order process.     

Effect of chronic exposure to EPN and to Guthion on the critical swimming speed and brain acetylcholinesterase activity of Cyprinodon variegatus

Swimming performance of the estuarine sheepshead minnow, Cyprinodon variegatus, was measured in a stamina tunnel at the end of life-cycle toxicity tests with the organophosphate pesticides EPN (265 days) and Guthion (219 days). Effects of acetylcholinesterase (AChE) inhibition were also determined. These measures were compared to survival, growth and reproduction data obtained in the life-cycle toxicity test. Significant effects on swimming stamina were detected in fish exposed to 2.2 μg EPN/1 (57% that of control fish) and in fish exposed to 4.1 μgEPN/1 (46% of controls). Survival and growth were reduced only in 7.9 μg EPN/1. Swimming performance was not affected by Guthion concentrations up to 0.5 μg/1, a concentration affecting reproduction. AChE was significantly inhibited by all tested concentrations of EPN, 0.25 to 7.9 μg/1, and Guthion, 0.06 to 0.50 μg/1. Swimming stamina may be an important endpoint to include with measurements of effects on survival, growth and reproduction in chronic toxicity tests with fish, but the relation of AChE inhibition to these endpoints is uncertain.