Can specific THz fields induce collective base-flipping in DNA? A stochastic averaging and resonant enhancement investigation based on a new mesoscopic model.

We study the metastability, internal frequencies, activation mechanism, energy transfer, and the collective base-flipping in a mesoscopic DNA via resonance with specific electric fields. Our new mesoscopic DNA model takes into account not only the issues of helicity and the coupling of an electric field with the base dipole moments, but also includes environmental effects, such as fluid viscosity and thermal noise. Also, all the parameter values are chosen to best represent the typical values for the opening and closing dynamics of a DNA. Our study shows that while the mesoscopic DNA is metastable and robust to environmental effects, it is vulnerable to certain frequencies that could be targeted by specific THz fields for triggering its collective base-flipping dynamics and causing large amplitude separation of base pairs. Based on applying the Freidlin-Wentzell method of stochastic averaging and the newly developed theory of resonant enhancement to our mesoscopic DNA model, our semi-analytic estimates show that the required fields should be THz fields with frequencies around 0.28 THz and with amplitudes in the order of 450 kV/cm. These estimates compare well with the experimental data of Titova et al., which have demonstrated that they could affect the function of DNA in human skin tissues by THz pulses with frequencies around 0.5 THz and with a peak electric field at 220 kV/cm. Moreover, our estimates also conform to a number of other experimental results, which appeared in the last couple years.

Correction: Kim et al. Mito-TIPTP Increases Mitochondrial Function by Repressing the Rubicon-p22phox Interaction in Colitis-Induced Mice. Antioxidants 2021, 10, 1954.

In the original publication [...].

Single-string, closed-loop fixation modification to reposit a dislocated triple-looped haptic intraocular lens.

A technique using the single-string, closed-loop fixation method to reposit dislocated triple-looped haptic intraocular lens (IOL)-capsular bag complex is described. The long needle or curved needle with a 10-0/8-0 polypropylene suture and a 27/30-gauge needle were used as the guide needle to pass through the fenestrated haptics twice. The scleral interlaminar course was used as the fixed point. Last, a fixation knot was created in the sclerotomy by the 2 ends of the thread to close the suture loop for IOL fixation. Another knot was created about 2 to 3 mm from the exit point and was intrasclerally anchored by the aid of the attached needle. 4 eyes from 4 consecutive patients were studied retrospectively; during all follow-up visits, the IOLs were well centered and stable, and no suture erosion, hypotony, scleral atrophy, chronic inflammation, retinal tears, and/or detachments were observed.

Point mutation of V252 in neomycin C epimerase enlarges substrate-binding pocket and improves neomycin B accumulation in Streptomyces fradiae.

Neomycin, an aminoglycoside antibiotic with broad-spectrum antibacterial resistance, is widely used in pharmaceutical and agricultural fields. However, separation and purification of neomycin B as an active substance from Streptomyces fradiae are complicated. Although NeoN can catalyze conversion of neomycin C to neomycin B, the underlying catalytic mechanism is still unclear. In this study, the genomic information of high-yielding mutant S. fradiae SF-2 was elucidated using whole-genome sequencing. Subsequently, the mechanism of NeoN in catalyzing conversion of neomycin C to neomycin B was resolved based on NeoN-SAM-neomycin C ternary complex. Mutant NeoNV252A showed improved NeoN activity, and the recombinant strain SF-2-NeoNV252A accumulated 16,766.6 U/mL neomycin B, with a decrease in neomycin C ratio from 16.1% to 6.28%, when compared with the parental strain SF-2. In summary, this study analyzed the catalytic mechanism of NeoN, providing significant reference for rational design of NeoN to improve neomycin B production and weaken the proportion of neomycin C.

Mito-TIPTP Increases Mitochondrial Function by Repressing the Rubicon-p22phox Interaction in Colitis-Induced Mice.

The run/cysteine-rich-domain-containing Beclin1-interacting autophagy protein (Rubicon) is essential for the regulation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase by interacting with p22phox to trigger the production of reactive oxygen species (ROS) in immune cells. In a previous study, we demonstrated that the interaction of Rubicon with p22phox increases cellular ROS levels. The correlation between Rubicon and mitochondrial ROS (mtROS) is poorly understood. Here, we report that Rubicon interacts with p22phox in the outer mitochondrial membrane in macrophages and patients with human ulcerative colitis. Upon lipopolysaccharide (LPS) activation, the binding of Rubicon to p22phox was elevated, and increased not only cellular ROS levels but also mtROS, with an impairment of mitochondrial complex III and mitochondrial biogenesis in macrophages. Furthermore, increased Rubicon decreases mitochondrial metabolic flux in macrophages. Mito-TIPTP, which is a p22phox inhibitor containing a mitochondrial translocation signal, enhances mitochondrial function by inhibiting the association between Rubicon and p22phox in LPS-primed bone-marrow-derived macrophages (BMDMs) treated with adenosine triphosphate (ATP) or dextran sulfate sodium (DSS). Remarkably, Mito-TIPTP exhibited a therapeutic effect by decreasing mtROS in DSS-induced acute or chronic colitis mouse models. Thus, our findings suggest that Mito-TIPTP is a potential therapeutic agent for colitis by inhibiting the interaction between Rubicon and p22phox to recover mitochondrial function.

MiR-224 ameliorates inflammation and symptoms in mouse model of allergic rhinitis by targeting CDK9.

OBJECTIVES: To explore the regulatory effects of microRNA (miRNA)-224 and its potential target gene, cyclin dependent kinase 9 (CDK9), in the pathological process of allergic rhinitis (AR). METHODS: To investigate the role of miR-224 and CDK9, it was screened by bioinformatics prediction software and verified by dual-luciferase reporter assay. The mouse model of AR was established by ovalbumin (OVA).The animal models were intervened with miR-224 agomir, negative control agomir, and saline respectively. The symptoms of sneezing and nasal rubbing were recorded. The expressions of miR224, CDK9, and cytokines in the nasal mucosa of different groups were analyzed by rt-PCR or western blotting. Enzyme-linked immunoassay (ELISA) was used to evaluate the levels of IgE and Histamine (HA) in the serum. The infiltration of inflammatory cells in the nasal mucosa was studied by immunohistochemistry. The expression and distribution of CDK9 in the nasal mucosa of mice were revealed by immunofluorescence. RESULTS: In the nasal mucosa of the animal models, the level of miR-224 was downregulated, while that of CDK9 was upregulated. The upregulation of miR-224 by miR-224 agomir reduced the frequencies of nasal rubbing and sneezing, the expression of CDK9, the levels of cytokines, and the concentrations of IgE and HA. Moreover, miR-224 appeared to attenuate the infiltration of inflammatory cells and hypersecretion of glands in the nasal mucosa. The expression of CDK9, which was distributed under the mucosa, especially in the submucosa interstitial tissue, was significantly reduced. CONCLUSION: MiR-224 affected the pathogenesis of AR by targeting CDK9. It proves that miR-224 could be a novel potential therapeutic target for AR.

Autologous tenon capsule packing to treat posterior exit wound of penetrating injury: A case report.

BACKGROUND: This study reports a case of autologous tenon capsule packing to treat the posterior exit wound of penetrating injury. CASE SUMMARY: To treat a 58-year-old male patient with penetrating eyeball injury caused by an iron sheet, we used autologous tenon capsule packing. Two months after removal of the silicone oil, the corrected visual acuity was 0.3, the retina was flat, the tenon capsule graft was in place, the posterior wound closed well, and the intraocular pressure was 15.8 mmHg. CONCLUSION: Autologous tenon capsule packing to treat the posterior exit wound of penetrating injury is safe and effective.

Scleral Buckling with Viscoelastics or Gas Injection for Bulging Retinal Detachments: A Retrospective Cohort Study.

OBJECTIVE: To examine the use of a viscoelastic agent instead of air in the vitreous cavity during surgery for scleral buckling. METHODS: This was a retrospective cohort study of patients who underwent scleral buckling surgery for bulging rhegmatogenous retinal detachment (RRD) at Ningbo Eye Hospital from 07/2016 to 12/2019. The patients were grouped into drainage, air injection, cryotherapy and explant (DACE) and drainage, viscoelastic injection, cryotherapy, and explant (DVCE) groups, which were comparatively assessed. RESULTS: There were 25 and 22 patients in the DVCE and DACE groups, respectively. The surgery was significantly shorter with DVCE than DACE (P < 0.05), with less intraoperative external pressure adjustment (P < 0.05). BCVA was lower in the DVCE group at 1 week compared with the DACE group (P < 0.05). Successful retinal reattachment was observed in 92.0% and 81.8% of the DVCE and DACE groups, respectively (P < 0.05). Cases requiring laser replenishing after the operation were less in the DVCE group compared with the DACE group (P < 0.05). There were no differences in complications and intraocular pressure between the two groups (all P < 0.05). CONCLUSION: DVCE has better operative characteristics and faster vision recovery than DACE, with similar outcomes.

Salvianolic acid B inhibits myofibroblast differentiation and extracellular matrix accumulation in nasal polyp fibroblasts via the TGF-ß1 signaling pathway.

In the process of nasal tissue remodeling, nasal fibroblasts serve an important role via myofibroblast differentiation and the production of extracellular matrix (ECM). Nasal fibroblast abnormalities can lead to conditions such as chronic rhinosinusitis. Salvianolic acid B (Sal B), a water-soluble active pharmaceutical compound extract from the root of the traditional Chinese medicine Salvia miltiorrhiza, displays antioxidative, antiproliferative and antifibrosis properties. The present study aimed to investigate the mechanism underlying the effects of Sal B on nasal polyp fibroblast (NPF) myofibroblast differentiation and ECM accumulation. Primary NPFs were obtained from nasal polyps of patients with chronic sinusitis. The proliferative and cytotoxic effects of Sal B on NPFs were evaluated by performing the Cell Counting Kit-8 assay. The Transwell assay was conducted to assess cell migration. α-smooth muscle actin (α-SMA), TGF-ß1 receptor (TßR)-I, TßR-II, Smad2/3 mRNA and protein expression levels and (p)-Smad2/3 phosphorylation levels were measured via reverse transcription-quantitative PCR and western blotting, respectively. Type III collagen and fibronectin levels were analyzed by ELISA. The results indicated that Sal B significantly downregulated TGF-ß1-induced α-SMA, fibronectin and collagen III expression levels in NPFs. Similarly, Sal B significantly decreased TGF-ß1-induced TßR-I, TßR-II, p-Smad2/3, MMP-2 and MMP-9 mRNA and protein expression levels in NPFs. Furthermore, Sal B significantly decreased TGF-ß1-induced NPF migration. Therefore, the present study indicated that Sal B inhibited myofibroblast differentiation and ECM accumulation in nasal fibroblasts, suggesting that Sal B may inhibit nasal polyp formation via certain mechanisms.

Factors associated with difficult intravenous access in the pediatric emergency department.

BACKGROUND: Successful intravenous catheter placement plays a vital role in the pediatric emergency department. We assessed pediatric emergency department-related factors associated with difficult intravenous catheter placement. METHOD: We retrospectively reviewed the electronic medical records of patients younger than 18 years who had an intravenous catheter placement attempt during their pediatric emergency department stay. Difficult intravenous access was defined as intravenous catheter placement requiring more than one attempt. The demographic-, clinical- and procedure-related factors were collected, and a logistic regression analysis was used to evaluate the factors associated with difficult intravenous access. RESULT: In total, 925 patients were enrolled, and 77 (8.32%) cases had difficult intravenous access. The median age of the patients was 3.0 (interquartile range = 1-9) years, and 496 (53.6%) patients were male. After adjustment, we found that age (odds ratio = 0.91, 95% confidence interval = (0.85-0.98), p = 0.01); a history of prematurity (odds ratio = 2.31, 95% confidence interval (1.08-4.98), p = 0.03); the intravenous catheter insertion site (foot versus hand odds ratio = 5.65, 95% confidence interval = (2.97-10.75); p < 0.001); and the experience of the provider (<6 months versus ⩾12 months odds ratio = 4.59, 95% confidence interval = (1.92-11.01), p = 0.01) were associated with difficult intravenous access. However, the acuity of disease, crowdedness at the pediatric emergency department, sex, vein visibility, vein palpability, intravenous catheter size, patients' experience with intravenous access, and time of day were not significantly correlated with difficult intravenous access. CONCLUSION: The success rate of intravenous catheter placement at the pediatric emergency department could be improved by experienced providers. The acuity of disease and crowdedness at the pediatric emergency department were not significantly associated factors.