Combination Antifungal Therapy Involving Amphotericin B,Rapamycin and 5-Fluorocytosine Using PEG-Phospholipid Micelles

PURPOSE: Rapamycin and 5-fluorocytosine (5-FC) are antifungal agents with unique mechanisms of activity, with potential for cooperative interaction with AmB. Combination antifungal therapy involving conventional AmB has been restricted by poor physical stability and compatibility with antifungal drugs and vehicles. METHODS: AmB and rapamycin were encapsulated in 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy poly(ethylene glycol) (PEG-DSPE) micelles using a solvent evaporation method. The physical stability of micelle encapsulated AmB and rapamycin with 5-FC and saline was evaluated using dynamic light scattering (DLS). In vitro susceptibility of Candida albicans isolates to 5-FC and PEG-DSPE micelle solubilized AmB and rapamycin has been evaluated. Interactive effects have been quantified using a checkerboard layout. RESULTS: In contrast with conventional AmB, PEG-DSPE micelles encapsulating AmB and rapamycin are compatible with saline and 5-FC over 12 h. The solubilized drugs retain high level of potency in vitro. The combination of solubilized AmB and rapamycin was indifferent, as fractional inhibitory concentration (FIC) index and combination index (CI) values were approximately 1. Combinations of solubilized AmB or rapamycin with 5-FC, and the three-drug combination were moderately synergistic since the FIC index and CI values were consistent less than 1. CONCLUSIONS: These results indicate that AmB solubilized in PEG-DSPE micelles is compatible with solubilized rapamycin and 5-FC. The indifferent or moderately synergistic activity of combinations is encouraging and warrants further investigation in appropriate rodent models.     

Analysis of symptomatic and asymptomatic primary root canal infections in adult Norwegian patients

Introduction

This molecular study analyzed the microbiota of primary root canal infections from adult Norwegian patients.

Methods

Samples were taken from the necrotic root canals of teeth with symptomatic (n = 13) or asymptomatic (n = 21) apical periodontitis and chronic apical abscesses (n = 9). DNA was extracted from samples, and bacterial identifications were performed by a closed-ended reverse-capture checkerboard approach targeting 50 candidate endodontic pathogens.

Results

Bacterial DNA was detected in all cases. In teeth with asymptomatic apical periodontitis, the most frequent taxa were Dialister invisus (71%), Fusobacterium nucleatum (62%), and Porphyromonas endodontalis (62%). In chronic apical abscesses, the most prevalent taxa were P. endodontalis (100%), D. invisus (89%), Parvimonas micra (78%), and Solobacterium moorei (78%). In teeth with symptomatic apical periodontitis, the most prevalent taxa were D. invisus, P. endodontalis, S. moorei, Propionibacterium acnes, and Streptococcus species (all in 69%). None of the targeted taxa were significantly associated with either sinus tract or pain (P > .05), except for Selenomonas sputigena, which was more frequently found in painful cases (P = .04). No taxa were found in significantly higher levels in any conditions (P > .05). Cluster analyses revealed bacterial groupings that differed between cases with and without pain.

Conclusions

Although basically the same species were highly prevalent in the different conditions examined and none of the most prevalent taxa were positively associated with symptoms, results revealed that species formed different partnerships and associations in samples from teeth with or without pain. Therefore, it is possible that more virulent multispecies communities can form as a result of overall bacterial combinations and give rise to acute inflammation.     

棋盘格翻转的视野刺激区域对硬脑膜上皮质脑电的影响

To explore the effect of the location of a visual stimulus on neural responses in the primary visual cortex (V1), a micro-electromechanical system-based microelectrode array with nine channels was implanted on the cerebral dura mater of V1 in adult cats. 2 Hz pattern reversal checkerboard stimuli were used to stimulate the four visual quadrants (i.e., upper left, upper right, lower left, and lower right fields). The results showed that there was a N75 component of the visual evoked potential around 50-80 ms after the onset of a checkerboard stimulus, and the onset of these N75 peaks varied with different stimulus locations. The checkerboard stimuli induced shorter latencies in the contralateral V1 than in the ipsilateral V1, while the checkerboard stimulus in the upper half visual field induced shorter latencies for N75. These results suggested that the pattern-reversal stimuli induced neural activities in V1 that can be recorded with multichannel microelectrodes, and more detailed temporal and spatial properties can be measured.     

头孢噻利对铜绿假单胞菌和甲氧西林耐药金葡菌的体外抗菌作用研究

目的探讨头孢噻利与阿米卡星对铜绿假单胞菌及头孢噻利与万古霉素对MRSA的体外联合抗菌作用,为联合抗菌治疗提供依据。方法收集30株不同耐药表型的铜绿假单胞菌和30株耐甲氧西林的金葡菌(MRSA),采用棋盘法测定头孢噻利与阿米卡星、头孢噻利与万古霉素的联合抗菌作用。结果头孢噻利与阿米卡星联合对铜绿假单胞菌具有协同、相加和无关作用者分别占26.7%、40.0%和33.3%。头孢噻利与万古霉素联合对MRSA主要是相加作用(63.3%),其余为无关作用(36.7%)。两组细菌中均未发现拮抗现象。结论头孢噻利与阿米卡星对铜绿假单胞菌及头孢噻利与万古霉素对MRSA在体外均表现出较好的联合抗菌作用。     

以棋盘法测定汉防己甲素与伊曲康唑的体外联合抗烟曲霉作用

目的 探讨汉防己甲素在体外对伊曲康唑抗烟曲霉活性是否有增效作用。方法 参照美国临床和实验室标准协会（CLSI）推荐的M38-A2方案,采用棋盘式微量液基稀释法,以21株烟曲霉临床株为研究对象,测定汉防己甲素联合伊曲康唑对其的抗真菌活性,以OD值测定法判读最低抑菌浓度,并以FICI法评价结果,同时以其中的AF46株为代表,用等效线图解法验证结果。结果 汉防己甲素与伊曲康唑单独作用于上述烟曲霉临床株的最低抑菌浓度值分别为256~512 μg/mL、0.125~32 μg/mL,联合用药时的最低抑菌浓度值分别降至8~64 μg/mL、0.03~2 μg/mL,且终点清晰,“拖尾现象”消失,FICI值为0.08~0.38,均表现为显著协同作用。AF46株的等效曲线呈凹形,也表明具有协同作用。结论 汉防己甲素在体外对伊曲康唑抗烟曲霉活性有显著增效作用。     

2种方法检测热毒宁与头孢哌酮钠/舒巴坦钠对广泛耐药鲍曼不动杆菌协同作用的比较

目的观察微量肉汤棋盘稀释法与纸片扩散法检测体外环境下中药热毒宁联合头孢哌酮钠/舒巴坦钠(SCF)对广泛耐药鲍曼不动杆菌(XDR-AB)协同作用的结果,比较两者的符合性,以指导临床用药。方法筛选2015年该院住院患者感染的XDR-AB共12株,将菌株培养传代,先采用微量肉汤棋盘稀释法检测SCF和热毒宁单独及联合使用时的最低抑菌浓度(MIC),通过计算判断是否有协同作用,再使用纸片扩散法检测抑菌环直径和药物的协同作用。结果微量肉汤棋盘稀释法检测热毒宁与SCF联合用药时,与单独用药时相比,MIC均有不同程度下降,热毒宁与SCF联合用药时的抑菌浓度指数均小于或等于0.5,具有协同作用。纸片扩散法测定出热毒宁原液的抑菌环直径为10mm,不同XDR-AB菌株对SCF的抑菌环直径有所差异,其中5株为15 mm,3株为16 mm,4株为17 mm。但当热毒宁与SCF联合作用时,抑菌环直径扩大,12株也都出现了协同作用。结论体外环境下,热毒宁联合SCF对XDR-AB有很好的协同作用,2种方法结果一致,虽然纸片法更加简便,但结果判断带有一定主观性,需要有经验的人员操作。     

Assessing the levels of immunoglobulins in the saliva of diabetic individuals with periodontitis using checkerboard immunodetection

BACKGROUND: Current methods for determining salivary antibodies are cumbersome for large-scale screenings. OBJECTIVES: To test checkerboard immunodetection for monitoring salivary antibodies and to profile them in diabetic individuals with periodontitis. METHODS: Salivary anti-Porphyromonas gingivalis, anti-Actinobacillus actinomycetemcomitans and total IgA levels of 10 individuals were compared using checkerboard immunoblotting and enzyme-linked immunosorbent assay (ELISA). RESULTS: Close correlation between both methods was found in anti-P. gingivalis IgA and total IgA, but not in anti-A. actinomycetemcomitans IgA, because of high background levels in ELISA. Thereafter, checkerboard immunodetection was used to compare salivary antibodies of 20 adult type II diabetic with 32 non-diabetic individuals with (n=22) or without (n=10) periodontitis. Patients with periodontitis (regardless of their diabetic condition) expressed increased levels of total IgA in both whole and parotid saliva, but reduced levels of anti-A. actinomycetemcomitans IgA in whole saliva. Consequently, the proportion of anti-A. actinomycetemcomitans IgA in the total IgA was lower in saliva of patients with periodontitis compared with healthy controls. CONCLUSIONS: Checkerboard immunodetection was reliable and economical for screening saliva samples for multiple antibody reactions. Our results support previous reports which suggested that patients with periodontitis are able to secrete high levels of salivary Ig, but are hampered in targeting their salivary response toward A. actinomycetemcomitans.     

大蒜素联合不同药物对多重耐药鲍曼不动杆菌的体外抗菌作用

目的评价大蒜素单用及其联合亚胺培南或头孢哌酮/舒巴坦对多耐药鲍曼不动杆菌的体外抗菌作用。方法用微量肉汤稀释法,分别测定大蒜素、亚胺培南、头孢哌酮/舒巴坦对30株多耐药鲍曼不动杆菌的最低抑菌浓度(MIC);同时测定大蒜素与亚胺培南、大蒜素与头孢哌酮/舒巴坦组合药物对该菌株的MIC,计算出部分抑菌浓度指数(FICI)。结果大蒜素单药对鲍曼不动杆菌的MICrange为16～64μg.mL-1,MIC50为32μg.mL-1,MIC90为32μg.mL-1。大蒜素联合亚胺培南和大蒜素联合头孢哌酮/舒巴坦的FICI范围均为0.31～1.50。结论大蒜素单药对鲍曼不动杆菌有明显的体外抑菌作用;亚胺培南和头孢哌酮/舒巴坦均可增强大蒜的体外抗菌活性。     

万古霉素联合阿奇霉素对形成生物被膜耐甲氧西林金黄色葡萄球菌的体外抗菌效果分析

目的  探讨体外万古霉素与阿奇霉素联合应用对形成生物被膜的耐甲氧西林金黄色葡萄球菌（MRSA）的抗菌效果。方法  使用头孢西丁纸片扩散法和MRSA胶乳凝集实验确定MRSA,采用刚果红培养基判断生物被膜的形成,通过肉汤稀释法将万古霉素和阿奇霉素进行棋盘格联合药敏试验,测出不同浓度下的抑菌指数（FIC）,据此判定两药联用后所呈现出的相关效应。结果  万古霉素和阿奇霉素联用组最小抑菌浓度（MIC）明显低于各单药组,两药联用主要表现为相加作用（88.2%）和协同作用（11.8%）,无无关作用和拮抗作用。相加作用时FIC为0.5～1.0;协同作用时FIC≤0.5。结论  万古霉素联用阿奇霉素对生物被膜形成的MRSA具有明显的体外抑菌效果,可以指导临床有效地降低药物使用剂量,减少毒副作用。

     

Pattern Reversal ERG and VEP – Comparison of Stimulation by LED, Monitor and a Maxwellian-view System

Purpose: Pattern stimulation is widely used to detect inner retinal dysfunction. In this work we describe a pattern stimulation technique with LEDs and compare the results with conventional methods. Methods: PERG and VEP were derived from three normal subjects. Three different techniques were used to generate a checkerboard pattern reversal stimulus: a 70 Hz monitor, a Maxwellian-view system equipped with a Xenon-arc lamp and a mechanical mirror system, and a LED array (Roland Consult) consisting of 100 white LEDs. Two kinds of luminance (125 and 340 cd/m²) and four temporal frequencies (4, 8, 12 and 24 reversals per second) were studied on three healthy subjects. Additionally, a luminance tuning experiment (30, 60, 90, 125 and 340 cd/m²) was performed on one subject. Results: Comparison of different stimulation techniques shows reproducible responses of PERG and VEP with all three methods. The LED array leads to slightly smaller amplitudes than both other techniques, which we ascribe to the design of the LED field. No difference of peak times or phases was noticed between different stimulation techniques. A luminance dependency of PERG and VEP is noticeable using stimulation with LED: with decreasing luminance we measured increasing peak times of PERG and VEP and decreasing amplitude of PERG. Conclusion: We conclude that central retinal stimulation with checkerboard pattern reversal is possible with LED. It gives comparable results to monitor and Maxwellian-view system.