Comparison of scanning electron microscopy findings regarding biofilm colonization with microbiological results in nasolacrimal stents for external, endoscopic and transcanalicular dacryocystorhinostomy

AIM:To compare bacterial biofilm colonization in lacrimal stents following external dacryocystorhinostomy (EX-DCR), endoscopic dacryocystorhinostomy (EN-DCR), and transcanalicular dacryocystorhinostomy (TC-DCR) with multidiode laser.METHODS: This prospective study included 30 consecutive patients with nasolacrimal duct obstruction who underwent EXT-, EN-, or TC-DCR. Thirty removed lacrimal stent fragments and conjunctival samples were cultured. The lacrimal stent biofilms were examined by scanning electron microscopy (SEM).RESULTS:Eleven (36.7%) of the 30 lacrimal stent cultures were positive for aerobic bacteria (most commonly Staphylococcus epidermidis and Pseudomonas aeruginosa). However anaerobic bacteria and fungi were not identified in the lacrimal stent cultures. Twenty-seven (90%) patients had biofilm-positive lacrimal stents. The conjunctival culture positivity after the DCR, biofilm positivity on stents, the grade of biofilm colonization, and the presence of mucus and coccoid and rod-shaped organisms did not significantly differ between any of the groups (P＞0.05). However, a significant difference was found when the SEM results were compared to the results of the lacrimal stent and conjunctival cultures (P＜0.001).CONCLUSION: Type of dacryocystorhinostomy (DCR) surgery did not affect the biofilm colonization of the lacrimal stents. SEM also appears to be more precise than microbiological culture for evaluating the presence of biofilms on lacrimal stents.     

Effects of erbium:yttrium–aluminum–garnet and neodymium:yttrium–aluminum–garnet laser hypersensitivity treatment parameters on the bond strength of self-etch adhesives

This in vitro study evaluated the shear bond strength (SBS) of two self-etch adhesives to coronal and root dentin treated with erbium:yttrium–aluminum–garnet (Er:YAG) or neodymium:yttrium–aluminum–garnet (Nd:YAG) lasers for dentin hypersensitivity. The coronal and root dentin surfaces of 60 extracted human cuspids were divided into three groups (n = 20): (1) control (without treatment); (2) treated with Er:YAG; (3) treated with Nd:YAG laser and a one-step (S3) or two-step self-etch adhesive (SE). A nano-composite was applied and SBS tests were performed. The mean SBS values were calculated, failure modes were determined, and data were subjected to statistical analysis (P = 0.05). Control/SE exhibited higher values than did control/S3 and Nd:YAG/S3 on coronal dentin (P < 0.05). No significant differences were observed between the SE and S3 groups in root dentin (P > 0.05). Comparisons of two dentin substrates did not show any difference except control/SE (P < 0.05). The failure modes were mainly adhesive. The SBSs of self-etch adhesives to Er:YAG or Nd:YAG laser-treated surfaces were comparable with control for both coronal and root dentin.     

Renin–angiotensin gene polymorphisms in relation to severe chronic periodontitis

Aim: Evidence suggests that the ultimate product of the renin–angiotensin system (RAS), angiotensin II, exerts inflammatory actions. The present study aimed to evaluate the inter‐relation between gene polymorphisms of the RAS components; angiotensin converting enzyme (ACE), angiotensinogen (AGT) and angiotensin II type‐I receptor (AT1R), and severe chronic periodontitis (CP). Material and Methods: DNA was obtained from peripheral blood of 90 CP patients and 126 periodontally healthy subjects, and the clinical parameters were recorded. ACE I/D, AGT M235T and AT1R A1166C polymorphisms were genotyped by the PCR–RFLP method. Chi‐square, anova and logistic regression methods were used in statistical analyses. Results: The frequency of the ACE D allele was significantly lower in the CP group than the healthy group (p_corr=0.015). CP subjects exhibited increased C allele carriage and C allele frequency of the AT1R gene (p_corr=0.03 and p_corr=0.03, respectively). All clinical parameters of CP patients were found to be similar in variant allele‐carrying and non‐carrying subjects (p>0.05). Conclusions: The present findings suggest that ACE I/D and AT1R polymorphisms might be associated with susceptibility to CP but not with disease severity. The D allele of ACE I/D might be associated with decreased, whereas the C variant of AT1R A1166C might be associated with an elevated risk for CP in Turkish population.     

Feasibility study of pre-clinical Thiel embalmed human cadaver for MR-guided focused ultrasound of the spine

Background Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive treatment option based on high acoustic absorption and minimal thermal conductivity of the bone to destroy nerves and reduce pain. There is lack of a preclinical validation tool with correct human anatomy. This work introduces usage of an ex-vivo Thiel embalmed human tissue model for preclinical verification of MRgFUS on intervertebral discs or bone metastases within the spinal body. Material and methods Thiel embalmed human cadaver was subjected to FUS sonication of the vertebra (with energies 250J, 420J, 600J) and the intervertebral disc (with energies 310J, 610J, 950J) of the lumbar spine for 20s of sonication under MR guidance. Results For the vertebra, maximum temperatures were recorded as 38?°C, 58.3?°C, 69?°C. The intervertebral disc reached maximum temperatures of 23.7?°C, 54?°C, 83?°C. The temperature measurements showed that the spinal canal and adjacent organs were not heated > 0.1?°C. Conclusions A heating pattern that can induce thermal ablation was achieved in the vertebral body and the intervertebral disc. Adjacent structures and nerves were not heated in lethal levels. Thus, the Thiel embalmed human cadaver can be a safe and efficient model for preclinical study of application of MRgFUS on the upper lumbar spine.     

Data Requirements for the Reliable Use of Atomic Pair Distribution Functions in Amorphous Pharmaceutical Fingerprinting

Purpose

To determine the optimal measurement strategy for fingerprinting condensed phases of pharmaceutical systems using atomic pair distribution functions (PDFs) obtained from data collected using several types of x-ray diffraction instruments.

Methods

PDFs of crystalline and amorphous-phase molecular systems derived from data accessible to copper-, molybdenum-, and silver-anode laboratory sources were compared to one another and synchrotron data using qualitative and quantitative methods.

Results

We find that reliable fingerprinting is still possible using silver and molybdenum laboratory sources, but data from copper anode laboratory sources are unreliable for fingerprinting, yielding ambiguous and potentially incorrect results.

Conclusion

The ambiguities make data measured using low energy x-rays unsuitable for fingerprinting active pharmaceutical ingredients and small molecule systems, and, in general, copper anode diffractometers are undesirable for this purpose; however, laboratory x-ray sources with either Mo or Ag anodes are well suited for this application.     

Reoperative lower extremity revascularization with cadaver vein for limb salvage

We evaluated our experience using cryopreserved cadaver vein allografts (CVGs) for infrageniculate revascularization in patients with a history of failed bypass or no suitable autogenous vein. Records of all patients who underwent lower extremity revascularization with CVG for critical limb ischemia were reviewed. Patient demographics, vessel treated, and postoperative course were analyzed. Patients who had a redo cadaver vein bypass were compared to those with a first-time cadaver vein bypass. Cumulative patency rates, limb salvage, mortality, and factors associated with outcomes were determined using the Kaplan-Meier method with Cox proportional hazards. Between January 2000 and December 2006, 66 CVGs were done in 56 patients out of 1,726 total bypasses. There were 36 men and 20 women, and the mean age was 71.67 +/- 10.50 years. Mean follow-up was 12.12 +/- 14.16 months. Seventy-eight percent of patients had previous bypasses, and 50% of all failed bypasses were failed expanded polytetrafluoroethylene bypasses. Operative indications were tissue loss (73%) and ischemic rest pain (27%). The mean preoperative ankle-brachial index was 0.43 +/- 0.16, and this increased to 0.89 +/- 0.18 at 30 days (p = 0.001). Procedure-related complications included graft infection (3, 4%), graft thrombosis (3, 4%), pseudoaneurysm (3, 4%), and bleeding (2, 3%). Cumulative 1-year primary, primary assisted, secondary patencies, limb salvage, and survival rates with confidence intervals were 0.19 (0.10-0.36), 0.29 (0.18-0.47), 0.42 (0.29-0.60), 0.73 (0.62-0.86), and 0.77 (0.65-0.90). Reoperative procedures fared the same as primary procedures. Multivariable analysis showed that predictors for increased risk of secondary patency loss were age >70 (hazard ratio [HR] = 3.13, p = 0.009) and patients with secondary revascularization (HR = 3.36, p = 0.015). Older patients (HR = 2.92, p = 0.042) and those with renal insufficiency (HR = 2.92, p = 0.019) were at increased risk of mortality. CVG remains an option for reoperative lower limb revascularization for limb salvage if there is no autogenous vein available. However, patency rates are poor, and patients older than 70 are more likely to have inferior outcomes.     

Annealing helicase 2 (AH2), a DNA-rewinding motor with an HNH motif

The structure and integrity of DNA is of considerable biological and biomedical importance, and it is therefore critical to identify and to characterize enzymes that alter DNA structure. DNA helicases are ATP-driven motor proteins that unwind DNA. Conversely, HepA-related protein (HARP) protein (also known as SMARCAL1 and DNA-dependent ATPase A) is an annealing helicase that rewinds DNA in an ATP-dependent manner. To date, HARP is the only known annealing helicase. Here we report the identification of a second annealing helicase, which we term AH2, for annealing helicase 2. Like HARP, AH2 catalyzes the ATP-dependent rewinding of replication protein A (RPA)-bound complementary single-stranded DNA, but does not exhibit any detectable helicase activity. Unlike HARP, however, AH2 lacks a conserved RPA-binding domain and does not interact with RPA. In addition, AH2 contains an HNH motif, which is commonly found in bacteria and fungi and is often associated with nuclease activity. AH2 appears to be the only vertebrate protein with an HNH motif. Contrary to expectations, purified AH2 does not exhibit nuclease activity, but it remains possible that AH2 contains a latent nuclease that is activated under specific conditions. These structural and functional differences between AH2 and HARP suggest that different annealing helicases have distinct functions in the cell.