Scotopic contrast sensitivity and glare after accelerated corneal cross-linking

Background: The aim was to assess one-year changes in uncorrected and corrected contrast sensitivity (CS) and glare under scotopic conditions after accelerated cross-linking (CXL) using the 18 mW/cm2 protocol for the treatment of progressive keratoconus and compare results with unoperated controls. Methods: In this non-randomised clinical trial, 30 eyes were enrolled in the CXL group and 30 were assigned to the control group. Scotopic CS at spatial frequencies (SFs) of 0.5, 1.1, 2.2, 3.4, 7.1 and 15 cycles per degree (cpd) were assessed using the MonCv3System (Metrovision, Pérenchies, France) under scotopic conditions (0.5 lux) at baseline and at six and 12 months. Results: The mean ages of the participants in the CXL and control groups were 24.32 ± 5.17 and 30.93 ± 7.43 years, respectively (p < 0.001). After adjusting for age, changes in uncorrected and corrected CS and glare were similar in the two groups (all p > 0.05) except for corrected CS at SF 7.1 cpd (1.45 ± 4.31 versus 3.21 ± 4.69 dB, p = 0.010) and 15 cpd (1.12 ± 4.63 versus 3.03 ± 5.48 dB, p = 0.007), which were reduced as an effect of CXL. Based on covariate analyses, among corrected CS indices, corrected CS7.1 and CS15 were related to CXL and their baseline values (all p < 0.050). Uncorrected CS in all SFs and uncorrected and corrected glare were related to their pre-operative values (all p < 0.001). Conclusion: Accelerated CXL can reduce scotopic corrected CS at SFs higher than 7.0 cpd in cases with better baseline values of these parameters. Changes in uncorrected CS and glare are only a factor of baseline values and the indices reduce in cases with better baseline values after one year. © 2017 Optometry Australi

Evaluation of virulence factors and antibiotic resistance patterns in clinical urine isolates of klebsiella pneumoniae in Semnan, Iran

Background: Klebsiella pneumoniae as an opportunistic pathogen can be the cause of a range of nosocomial and community-acquired infections. Many virulence factors help these bacteria overcome an immune system and cause various diseases. K1 and K2 capsular antigens, also magA, wcaG, and rmpA are well-known K. pneumoniae virulence factors. Klebsiella pneumoniae has been revealed to have the ability to acquire resistance to many antibiotics, which cause treatment failure. Objectives: This study aimed at determining the prevalence of magA, wcaG, rmpA, Capsular type K1, Capsular type K2, TEM, and SHV in K. pneumoniae isolates. Methods: A total of 173 non-duplicate K. pneumoniae isolates were collected from two different hospitals in Semnan, Iran, from urine specimens. Klebsiella pneumoniae was identified by conventional bacteriological tests. Disk diffusion test was performed according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Detection of virulence factors, TEM, and SHV gene was performed by specific primers. Results: Frequency of virulence factors was as follow: capsular type K2: 32.9, rmpA: 20.2, capsular type K1: 6.9, and wcaG: 16.2. Also, the SHV and TEM were observed in 46.8 and 33.5, respectively. Antibiotics resistance rates were as follow, imipenem: 7.5, ciprofloxacin: 16.1, levofloxacin: 17.3, amoxicillin-clavulanic acid: 30, trimethoprim-sulfamethoxazole: 32.9, cefepime: 34.1, nitrofurantoin: 35.8, amikacin: 36.4, aztreonam: 39.3, ceftazidime: 42.7. Conclusions: Frequency of some virulence factors including capsular type K2, rmpA, wcaG, and also resistant rate to imipenem, amikacin, and ceftazidime were significantly higher than similar studies. Presence of virulence factors accompanied by drug resistance should make bacteria an infectious agent and lead to treatment failure. © 2018, Author(s)

New magnetic Co3O4/Fe3O4 doped polyaniline nanocomposite for the effective and rapid removal of nitrate ions from ground water samples

In the present study, a new nanocomposite of iron/cobalt oxides and magnetic nanoparticle doped with polyaniline (PANI-Co3O4@MNPs) was synthesized and subsequently, evaluated for its potential in decontaminating nitrate ions from ground water. Various important parameters such as pH, mass dosage, adsorption time, initial concentration, and temperature were experimentally investigated. The important surface and chemical properties of PANI-Co3O4@MNPs, such as surface morphology and roughness, composition and chemical structure were evaluated using field emission scanning electron microscope, energy-dispersive X-ray spectroscopy, and Fourier transform infrared. Finally, the removal of nitrate was assessed using kinetic, adsorption isotherm, and thermodynamic studies to investigate the underlying mechanism of the removal process. Maximum adsorption capacity was found to be 68.96 mg/g for nitrate ions at pH 6, adsorbent dosage 60 mg within 60 min. The kinetic studies and the adsorption isotherms have been well fitted using pseudo first and the Freundlich models respectively whereas the thermodynamic parameters have been described in terms of enthalpy, entropy, and Gibbs free energy which showed a negative value signifying that the adsorption process was exothermic and spontaneous in nature

Maxadilan Prevents Apoptosis in iPS Cells and Shows No Effects on the Pluripotent State or Karyotype

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a structurally endogenous peptide with many biological roles. Maxadilan, a 61-amino acid vasodilatory peptide, specifically activates the PACAP type I receptor (PAC1). Although PAC1 has been identified in embryonic stem cells, little is known about its presence or effects in human induced pluripotent stem (iPS) cells. In the present study, we investigated the expression of PAC1 in human iPS cells by reverse transcriptase polymerase chain reaction (RT-PCR) and western blot analysis. To study the physiological effects mediated by PAC1, we evaluated the role of maxadilan in preventing apoptotic cell death induced by ultraviolet C (UVC). After exposure to UVC, the iPS cells showed a marked reduction in cell viability and a parallel increase of apoptotic cells, as demonstrated by WST-8 analysis, annexin V/propidium iodide (PI) analysis and the terminal transferase dUTP nick end labeling (TUNEL) assay. The addition of 30 nM of maxadilan dramatically increased iPS cell viability and reduced the percentage of apoptotic cells. The anti-apoptotic effects of maxadilan were correlated to the downregulation of caspase-3 and caspase-9. Concomitantly, immunofluorescence, western blot analysis, real-time quantitative polymerase chain reaction (RT-qPCR) analysis and in vitro differentiation results showed that maxadilan did not affect the pluripotent state of iPS cells. Moreover, karyotype analysis showed that maxadilan did not affect the karyotype of iPS cells. In summary, these results demonstrate that PAC1 is present in iPS cells and that maxadilan effectively protects iPS cells against UVC-induced apoptotic cell death while not affecting the pluripotent state or karyotype

Regulation of Pax6 by CTCF during Induction of Mouse ES Cell Differentiation

Pax6 plays an important role in embryonic cell (ES) differentiation during embryonic development. Expression of Pax6 undergoes from a low level to high levels following ES cell differentiation to neural stem cells, and then fades away in most of the differentiated cell types. There is a limited knowledge concerning how Pax6 is regulated in ES cell differentiation. We report that Pax6 expression in mouse ES cells was controlled by CCCTC binding factor (CTCF) through a promoter repression mechanism. Pax6 expression was significantly enhanced while CTCF activity was kept in the constant during ES cell differentiation to radial glial cells. Instead, the interaction of CTCF with Pax6 gene was regulated by decreased CTCF occupancy in its binding motifs upstream from Pax6 P0 promoter following the course of ES cell differentiation. Reduced occupancy of CTCF in the binding motif region upstream from the P0 promoter was due to increased DNA methylations in the CpG sites identified in the region. Furthermore, changes in DNA methylation levels in vitro and in vivo effectively altered methylation status of these identified CpG sites, which affected ability of CTCF to interact with the P0 promoter, resulting in increases in Pax6 expression. We conclude that there is an epigenetic mechanism involving regulations of Pax6 gene during ES cell differentiation to neural stem cells, which is through increases or decreases in methylation levels of Pax6 gene to effectively alter the ability of CTCF in control of Pax6 expression, respectively

Histone H1 Depletion Impairs Embryonic Stem Cell Differentiation

Pluripotent embryonic stem cells (ESCs) are known to possess a relatively open chromatin structure; yet, despite efforts to characterize the chromatin signatures of ESCs, the role of chromatin compaction in stem cell fate and function remains elusive. Linker histone H1 is important for higher-order chromatin folding and is essential for mammalian embryogenesis. To investigate the role of H1 and chromatin compaction in stem cell pluripotency and differentiation, we examine the differentiation of embryonic stem cells that are depleted of multiple H1 subtypes. H1c/H1d/H1e triple null ESCs are more resistant to spontaneous differentiation in adherent monolayer culture upon removal of leukemia inhibitory factor. Similarly, the majority of the triple-H1 null embryoid bodies (EBs) lack morphological structures representing the three germ layers and retain gene expression signatures characteristic of undifferentiated ESCs. Furthermore, upon neural differentiation of EBs, triple-H1 null cell cultures are deficient in neurite outgrowth and lack efficient activation of neural markers. Finally, we discover that triple-H1 null embryos and EBs fail to fully repress the expression of the pluripotency genes in comparison with wild-type controls and that H1 depletion impairs DNA methylation and changes of histone marks at promoter regions necessary for efficiently silencing pluripotency gene Oct4 during stem cell differentiation and embryogenesis. In summary, we demonstrate that H1 plays a critical role in pluripotent stem cell differentiation, and our results suggest that H1 and chromatin compaction may mediate pluripotent stem cell differentiation through epigenetic repression of the pluripotency genes

Dabigatran etexilate, a novel oral direct thrombin inhibitor, for preventing thromboembolic events after knee replacement arthroplasty

Background: Dabigatran etexilate is one of the few direct thrombin inhibitors with anti-coagulant activities and the following distinctive features: taken orally, no need to closely monitor for complications, and no need for regular dose adjustments. Relying on the above mentioned valuable advantages, dabigatran etexilate can be considered as a premier choice for the prevention of venous thromboembolism after knee replacement arthroplasty. Methods: Forty five patients undergoing 50 knee replacement surgeries were included in this case-series study undertaken in Hazrat Rasool Akram and Khatam-alanbia Hospitals during 2010. Dabigatran etexilate was administered for the prevention of venous thromboembolism after knee arthroplasty in doses of 110 mg in the first 1-4 h after surgery followed by daily doses of 220 mg for 10 days. Patients were examined 3 times and a color Doppler sonography was performed on the 11th day to check for venous thrombosis. Finally, the patients were re-examined at the end of the 1st and the 3rd months postoperatively. Results: Only one out of 45 patients was diagnosed to have venous thrombosis on sonography done on the 11th day but the patient did not have any symptoms and repeat sonographies at the end of the 1st and the 3rd months postoperatively showed no venous thrombosis either. No complications were witnessed in the patients in the 3-month follow-up period. Conclusion: Dabigatran etexilate (220 mg/d for 10 days) can be an effective drug against venous thrombosis after total knee replacement surgeries