In vitro synergism of a water insoluble fraction of Uncaria tomentosa combined with fluconazole and terbinafine against resistant non-Candida albicans isolates

Context: Uncaria tomentosa D.C. (Rubiaceae) has several biological activities, including activity against resistant Candida strains. The synergistic interaction with terbinafine or fluconazole can be an important alternative to overcome this resistance.

Objectives: The potential synergy between a water insoluble fraction (WIF) from Uncaria tomentosa bark and the antifungals terbinafine (TRB) and fluconazole (FLZ) against non-Candida albicans resistant strains was investigated.

Materials and methods: TRB and FLZ, alone and combined with WIF, were tested by the checkerboard procedure using the micro-dilution technique against seven isolates of Candida glabrata and C. krusei. The molecular interactions occurring outside the cell wall were evaluated by scanning electron microscopy, Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC) analysis.

Results: The checkerboard inhibitory assay demonstrated synergy for WIF:TRB and WIF:FLZ combinations, respectively. The best synergistic cell damage was demonstrated unequivocally for the associations of WIF and TRB (1.95:4.0?μg/mL) and WIF and FLZ (1.95:8.0?μg/mL). The comparison of the FT-IR spectra of the antifungal alone, and in combination with WIF, allows recognizing clear differences in 3000, 1600, 1400, and 700–800?cm^?1 bands. Additionally, modifications on TRB and FLZ thermograms were clearly noticed after their combination with WIF.

Conclusions: DSC and infrared analysis demonstrated intermolecular interactions between WIF and either TRB or FLZ. Hence, quite likely the synergistic effect is related to interaction events occurring outside the cell wall between antifungal and cat’s claw proanthocyanidins. A direct action on the cell wall is suggested, without connection with the ABC efflux pump mechanism.     

Use of checkerboard DNA–DNA hybridization to evaluate the internal contamination of dental implants and comparison of bacterial leakage with cast or pre-machined abutments

Aims: To evaluate the checkerboard DNA–DNA hybridization method for detection and quantitation of bacteria from the internal parts of dental implants and to compare bacterial leakage from implants connected either to cast or to pre-machined abutments.
Materials and methods: Nine plastic abutments cast in a Ni–Cr alloy and nine pre-machined Co–Cr alloy abutments with plastic sleeves cast in Ni–Cr were connected to Branemark-compatible implants. A group of nine implants was used as control. The implants were inoculated with 3 μl of a solution containing 10⁸ cells/ml of Streptococcus sobrinus . Bacterial samples were immediately collected from the control implants while assemblies were completely immersed in 5 ml of sterile Tripty Soy Broth (TSB) medium. After 14 days of anaerobic incubation, occurrence of leakage at the implant–abutment interface was evaluated by assessing contamination of the TSB medium. Internal contamination of the implants was evaluated with the checkerboard DNA–DNA hybridization method.
Results: DNA–DNA hybridization was sensitive enough to detect and quantify the microorganism from the internal parts of the implants. No differences in leakage and in internal contamination were found between cast and pre-machined abutments. Bacterial scores in the control group were significantly higher than in the other groups ( P <0.05).
Conclusion: Bacterial leakage through the implant–abutment interface does not significantly differ when cast or pre-machined abutments are used. The checkerboard DNA–DNA hybridization technique is suitable for the evaluation of the internal contamination of dental implants although further studies are necessary to validate the use of computational methods for the improvement of the test accuracy.     

弱视儿童由棋盘格和条栅刺激产生的视觉诱发电位的比较

目的 用视觉诱发电位探讨弱视儿童对刺激信号的不同处理方式，更好地指导临床。方法 以斜视性弱视儿童作受试对象。用棋盘格和水平、垂直条栅作为刺激图形，在不同的空间频率下分别记录视觉诱发电位。对N75和P100峰的潜伏期做分析比较。结果 斜视性弱视眼由棋盘格诱发的反应在中高空间频率下显著长于由条栅诱发的反应。结论 视觉系统对棋盘格和条栅刺激采取了不完全相同的处理机制。而斜视性弱视对于棋盘格刺激的处理影响更大。在临床上，用中、高空间频率的棋盘格刺激产生的视觉诱发电位反应来检查弱视更敏感、更可靠。     

Functional Magnetic Resonance Imaging in Acute Unilateral Optic Neuritis

Despite good clinical criteria for diagnosing optic neuritis (ON), only a few techniques can precisely assess its impact on visual brain function. The authors studied whether functional magnetic resonance imaging (fMRI) of visual activation reliably reflects the cerebral consequences of acute unilateral ON, and how fMRI correlates with clinical function and visual evoked potentials (VEPs). Twenty ON patients, before and after steroid treatment, were compared to 20 controls. Each eye was stimulated separately with a checkerboard pattern reversing at 1, 2, 4, and 8 Hz. VEPs were recorded the same day. Initially, affected eye responses differed significantly from those of unaffected counterparts and controls in 12 patients. Post hoc classification by fMRI criteria was correct in approximately 85%. fMRI and VEP response parameters (as well as visual acuity) correlated significantly. The higher stimulation frequencies yielded greater fMRI responses from unaffected eyes, but not from affected eyes, in controls. The fMRI responses were quantifiable in every subject, whereas in 11 ON eyes, no VEPs were obtained during the acute stage. The authors conclude that fMRI is sensitive to the cerebral response alteration during ON and might therefore contribute to evaluating the temporal evolution of the visual functional deficit during recovery or therapy.     

In vivo antimicrobial effects of endodontic treatment procedures as assessed by molecular microbiologic techniques

Introduction

This culture-independent molecular microbiology study evaluated the antimicrobial effects of chemomechanical preparation supplemented by intracanal medication during treatment of teeth with apical periodontitis.

Methods

Samples were taken from 24 necrotic root canals at the baseline (S1), after chemomechanical preparation by using 2.5% NaOCl as the irrigant (S2), and after a 7-day interappointment medication with calcium hydroxide paste in either glycerin (CHG) or camphorated paramonochlorophenol/glycerin (CHPG) (S3). Bacterial, archaeal, and fungal presence was evaluated by polymerase chain reaction (PCR), and bacterial identifications were performed by a closed-ended reverse-capture checkerboard approach targeting 28 candidate endodontic pathogens.

Results

All S1 samples were positive for bacteria but negative for both archaea and fungi. Treatment procedures were highly effective in reducing the bacterial levels and number of taxa. Overall, 46% of S2 samples and 62.5% of S3 samples were PCR-negative for bacteria. Specifically, S2 and S3 samples yielded negative PCR results in 50% and 58% of the canals in the CHG group and in 42% and 67% of the canals in the CHPG group, respectively. Except for comparisons with S1 samples, no other statistically significant differences were observed for intragroup and intergroup comparisons involving S2 and S3. Several taxa were still found in S2 and S3 samples, and the most prevalent were Propionibacterium acnes and Streptococcus species.

Conclusions

Bacterial levels and number of taxa were substantially reduced after chemomechanical preparation and intracanal medication. However, presence of detectable levels of persisting bacteria in many cases indicates that the search for more effective antimicrobial treatment strategies should be stimulated.     

Comparison of the in vivo antimicrobial effectiveness of sodium hypochlorite and chlorhexidine used as root canal irrigants: a molecular microbiology study

Introduction

The purpose of this clinical study was to compare the antimicrobial effects of 2.5% sodium hypochlorite (NaOCl) and 0.12% chlorhexidine digluconate (CHX) when used as irrigants during treatment of teeth with apical periodontitis.

Methods

Forty-seven single-rooted single-canal teeth with necrotic pulps and asymptomatic apical periodontitis were selected for this study according to stringent inclusion/exclusion criteria. Bacterial samples were taken at the baseline (S1) and after (S2) chemomechanical preparation using 2.5% NaOCl (n = 30) or 0.12% CHX (n = 17) as the irrigant. Bacterial, archaeal, and fungal presence was evaluated by broad-range polymerase chain reaction (PCR), whereas bacterial identifications were performed by a closed-ended reverse-capture checkerboard approach targeting 28 candidate endodontic pathogens.

Results

All S1 samples were PCR positive for bacterial presence but negative for both archaea and fungi. Both NaOCl- and CHX-based protocols were significantly effective in reducing the bacterial levels and number of taxa. No significant differences were observed between them in all tested parameters including the incidence of negative PCR results in S2 (40% for NaOCl vs 47% for CHX, p = 0.8), reduction in the number of taxa per canal (p = 0.3), and reduction in the bacterial levels (p = 0.07). The most prevalent taxa in S2 samples from the NaOCl group were Propionibacterium acnes, Streptococcus species, Porphyromonas endodontalis, and Selenomonas sputigena. In the CHX group, the most prevalent taxa in S2 were Dialister invisus, Actinomyces israelii, Prevotella baroniae, Propionibacterium acidifaciens, and Streptococcus species.

Conclusions

Treatment protocols using irrigation with either NaOCl or CHX succeded in significantly reducing the the number of bacterial taxa and their levels in infected root canals, with no significant difference between these substances.     

Evidence for intact local connectivity but disrupted regional function in the occipital lobe in children and adolescents with schizophrenia

It has long been known that specific visual frequencies result in greater blood flow to the striate cortex. These peaks are thought to reflect synchrony of local neuronal firing that is reflective of local cortical networks. Since disrupted neural connectivity is a possible etiology for schizophrenia, our goal was to investigate whether localized connectivity, as measured by aberrant synchrony, is abnormal in children and adolescents with schizophrenia. Subjects included 25 children and adolescents with schizophrenia and 39 controls matched for age and gender. Subjects were scanned on a Siemens 3 Tesla Trio scanner while observing flashing checkerboard presented at either 1, 4, 8, or 12 Hz. Image processing included both a standard GLM model and a Fourier transform analysis. Patients had significantly smaller volume of activation in the occipital lobe compared to controls. There were no differences in the integral or percent signal change of the hemodynamic response function for each of the four frequencies. Occipital activation was stable during development between childhood and late adolescence. Finally, both patients and controls demonstrated an increased response between 4 and 8 Hz consistent with synchrony or entrainment in the neuronal response. Children and adolescents with schizophrenia had a significantly lower volume of activation in the occipital lobe in response to the flashing checkerboard task. However, features of intact local connectivity in patients, such as the hemodynamic response function and maximal response at 8 Hz, were normal. These results are consistent with abnormalities in regional connectivity with preserved local connectivity in early-onset schizophrenia.     

Comparative analysis of endodontic pathogens using checkerboard hybridization in relation to culture

Background/Aim:  The purpose of this study was to detect bacterial species and to quantify the total number of bacteria from samples of infected root canals before (S1) and after chemo-mechanical preparation using 2% chlorhexidine (CHX) gel as auxiliary chemical substance (S2) and after 7 days of intracanal dressing (S3) to compare microbial changes.
Method:  Twenty-four teeth were selected for this study. Chemo-mechanical preparation was performed using 2% CHX gel, then three different intracanal medicaments [M1: Ca(OH)₂ paste; M2: 2% CHX gel; and M3: Ca(OH)₂ paste plus 2% CHX gel] were used for 7 days. Checkerboard DNA–DNA hybridization was performed to detect 40 bacterial species. Aerobic and anaerobic culture techniques were used to determine the bacterial community by counting the colony-forming units (CFU).
Results:  The species most frequently identified by checkerboard in S1 were: Fusobacterium nucleatum ssp . polymorphum , Treponema socranskii ssp. socranskii , Parvimonas micra and Enterococcus faecalis. In S2 and S3 a total of eight different species were identified; and only one of them was gram-positive ( E. faecalis ). Microorganisms were not identified after use of M2 for 7 days. The quantification obtained on agar plates ranged from 4 × 10⁵ to 2.6 × 10⁶ CFU/ml in S1, mean CFU was reduced by 99.96% in S2, and there was no statistical difference between the CFU in S2 and S3.
Conclusion:  The antibacterial effect of the mechanical preparation supplemented by the use of an antibacterial auxiliary substance greatly reduced the microorganisms in the main root canal.     

两性霉素B和伊曲康唑的体外联合药敏试验分析

目的 研究两性霉素B和伊曲康唑在酵母菌体外联合药敏试验中的相互作用,为临床用药提供参考依据.方法 参照美国国家临床试验标准化委员会(NCCLS)提出的标准(M27-A方案),采用棋盘微量稀释法对28株酵母菌(隐球菌和念珠菌)进行了二性霉素B和伊曲康唑的体外联合药敏试验.结果 发现联合用药时各药物的MIC几何均值比单用有...