High-yield ligation-free assembly of DNA constructs with nucleosome positioning sequence repeats for single-molecule manipulation assays.

Force and torque spectroscopy have provided unprecedented insights into the mechanical properties, conformational transitions, and dynamics of DNA and DNA-protein complexes, notably nucleosomes. Reliable single-molecule manipulation measurements require, however, specific and stable attachment chemistries to tether the molecules of interest. Here, we present a functionalization strategy for DNA that enables high-yield production of constructs for torsionally constrained and very stable attachment. The method is based on two subsequent PCRs: first ∼380 bp long DNA strands are generated that contain multiple labels, which are used as "megaprimers" in a second PCR to generate ∼kbp long double-stranded DNA constructs with multiple labels at the respective ends. To achieve high-force stability, we use dibenzocyclooctyne-based click chemistry for covalent attachment to the surface and biotin-streptavidin coupling to the bead. The resulting tethers are torsionally constrained and extremely stable under load, with an average lifetime of 70 ± 3 h at 45 pN. The high yield of the approach enables nucleosome reconstitution by salt dialysis on the functionalized DNA, and we demonstrate proof-of-concept measurements on nucleosome assembly statistics and inner turn unwrapping under force. We anticipate that our approach will facilitate a range of studies of DNA interactions and nucleoprotein complexes under forces and torques.

Twisting DNA by salt.

The structure and properties of DNA depend on the environment, in particular the ion atmosphere. Here, we investigate how DNA twist -one of the central properties of DNA- changes with concentration and identity of the surrounding ions. To resolve how cations influence the twist, we combine single-molecule magnetic tweezer experiments and extensive all-atom molecular dynamics simulations. Two interconnected trends are observed for monovalent alkali and divalent alkaline earth cations. First, DNA twist increases monotonously with increasing concentration for all ions investigated. Second, for a given salt concentration, DNA twist strongly depends on cation identity. At 100 mM concentration, DNA twist increases as Na+ < K+ < Rb+ < Ba2+ < Li+ ≈ Cs+ < Sr2+ < Mg2+ < Ca2+. Our molecular dynamics simulations reveal that preferential binding of the cations to the DNA backbone or the nucleobases has opposing effects on DNA twist and provides the microscopic explanation of the observed ion specificity. However, the simulations also reveal shortcomings of existing force field parameters for Cs+ and Sr2+. The comprehensive view gained from our combined approach provides a foundation for understanding and predicting cation-induced structural changes both in nature and in DNA nanotechnology.

Intramedullary nailing for irreducible spiral subtrochanteric fractures: A comparison of cerclage and non-cerclage wiring.

PURPOSE: Intramedullary nailing is the preferred internal fixation technique for the treatment of subtrochanteric fractures because of its biomechanical advantages. However, no definitive conclusion has been reached regarding whether combined cable cerclage is required during intramedullary nailing treatment. This study is performed to compare the clinical effects of intramedullary nailing with cerclage and non-cerclage wiring in the treatment of irreducible spiral subtrochanteric fractures. METHODS: Patients with subtrochanteric fractures admitted to our center from January 2013 to December 2021 were retrospectively analyzed. The patients were enrolled in the case-control study according to the inclusion and exclusion criteria and divided into the non-cerclage group and the cerclage group. The patients' clinical data, including the operative time, intraoperative blood loss, hospital stay, reoperation rate, fracture union time, and Harris hip score, were compared between these 2 groups. Categorical variables were compared using Chi-square or Fisher's exact test. Continuous variables with normal distribution were presented as mean ± standard deviation and analyzed with Student's t-test. Non-normally distributed variables were expressed as median (Q1, Q3) and assessed using the Mann-Whitney test. A p < 0.05 was considered significant. RESULTS: In total, 69 patients were included in the study (35 patients in the non-cerclage group and 34 patients in the cerclage group). The baseline data of the 2 groups were comparable. There were no significant difference in the length of hospital stay (z = -0.391, p = 0.696), operative time (z = -1.289, p = 0.197), or intraoperative blood loss (z = -1.321, p = 0.186). However, compared with non-cerclage group, the fracture union time was shorter (z = -5.587, p < 0.001), the rate of nonunion was lower (χ2 = 6.030, p = 0.03), the anatomical reduction rate was higher (χ2 = 5.449, p = 0.03), and the Harris hip score was higher (z = -2.99, p = 0.003) in the cerclage group, all with statistically significant differences. CONCLUSIONS: Intramedullary nailing combined with cable cerclage wiring is a safe and reliable technique for the treatment of irreducible subtrochanteric fractures. This technique can improve the reduction effect, increase the stability of fracture fixation, shorten the fracture union time, reduce the occurrence of nonunion, and contribute to the recovery of hip joint function.

Peroxisome proliferator-activated receptors as therapeutic target for cancer.

Peroxisome proliferator-activated receptors (PPARs) are transcription factors belonging to the nuclear receptor family. There are three subtypes of PPARs, including PPAR-α, PPAR-ß/δ and PPAR-γ. They are expressed in different tissues and act by regulating the expression of target genes in the form of binding to ligands. Various subtypes of PPAR have been shown to have significant roles in a wide range of biological processes including lipid metabolism, body energy homeostasis, cell proliferation and differentiation, bone formation, tissue repair and remodelling. Recent studies have found that PPARs are closely related to tumours. They are involved in cancer cell growth, angiogenesis and tumour immune response, and are essential components in tumour progression and metastasis. As such, they have become a target for cancer therapy research. In this review, we discussed the current state of knowledge on the involvement of PPARs in cancer, including their role in tumourigenesis, the impact of PPARs in tumour microenvironment and the potential of using PPARs combinational therapy to treat cancer by targeting essential signal pathways, or as adjuvants to boost the effects of current chemo and immunotherapies. Our review highlights the complexity of PPARs in cancer and the need for a better understanding of the mechanism in order to design effective cancer therapies.

Brain CT can predict low lean mass in the elderly with cognitive impairment: a community-dwelling study.

BACKGROUND: The coexistence of sarcopenia and dementia in aging populations is not uncommon, and they may share common risk factors and pathophysiological pathways. This study aimed to evaluate the relationship between brain atrophy and low lean mass in the elderly with impaired cognitive function. METHODS: This cross-sectional study included 168 elderly patients who visited the multi-disciplinary dementia outpatient clinic at Kaohsiung Chang Gung Memorial Hospital for memory issues, between 2017 and 2019. The body composition was assessed by dual energy X-ray absorptiometry (DEXA) and CT based skeletal muscle index including L3 skeletal muscle index (L3SMI) and masseter muscle mass index (MSMI). The brain atrophy assessment was measured by CT based visual rating scale. Possible predictors of low lean mass in the elderly with cognitive impairement were identified by binary logistic regression. ROC curves were generated from binary logistic regression. RESULTS: Among the 81 participants, 43 (53%) remained at a normal appendicular skeletal muscle index (ASMI), whereas 38 (47%) showed low ASMI. Compared with the normal ASMI group, subjects with low ASMI exhibited significantly lower BMI, L3SMI, and MSMI (all p < 0.05), and showed significant brain atrophy as assessed by visual rating scale (p < 0.001). The accuracy of predictive models for low ASMI in the elderly with cognitive impairment were 0.875, (Area under curve (AUC) = 0.926, 95% confidence interval [CI] 0.844-0.972) in model 1 (combination of BMI, GCA and L3SMI) and 0.885, (Area under curve (AUC) = 0.931, [CI] 0.857-0.979) in model 2 (combination of BMI, GCA and MSMI). CONCLUSIONS: Global cortical atrophy and body mass index combined with either L3 skeletal muscle index or masseter skeletal muscle index can predict low lean mass in the elderly with cognitive impairment.

Effects of Ramosetron on Nausea and Vomiting Following Spinal Surgery: A Meta-Analysis.

Background: Spinal surgery is associated with severe pain within the first few days after surgery. Opioids are commonly used to control postoperative pain, but these can lead to postoperative nausea and vomiting (PONV). Therefore, use of more effective and better-tolerated agents would be beneficial for these patients. Serotonin receptor antagonists, such as ramosetron, have been used to reduce PONV in patients receiving anesthesia. Objective: We conducted a meta-analysis of published randomized controlled trials (RCTs) to compare the efficacy and tolerance of ramosetron to prevent PONV after spinal surgery. Methods: Medline, Embase, Cochrane Library, and Science Citation Index databases were systematically searched for relevant RCT articles published between January 1979 and November 2020. Full text articles restricted to English language that described RCTs comparing the use of ramosetron with other serotonin antagonists to treat PONV following spinal surgery in adult patients were considered for meta-analysis. Two reviewers independently performed study selection, quality assessment, and data extraction of all articles. Differences were resolved by a third reviewer. Results: The search identified 88 potentially relevant articles, of which only 3 met our selection criteria. Study drugs were administered at the end of spinal surgery in all 3 included articles. The meta-analysis revealed that ramosetron (0.3 mg) reduced the pain score (mean difference = -0.66; 95% CI -1.02 to -0.30), lowered the risk of PONV (risk ratio = 0.86; 95% CI, 0.76-0.97), and postoperative vomiting (risk ratio = 0.32; 95% CI, 0.17-0.60), and limited the use of rescue antiemetics (risk ratio = 0.66; 95% CI, 0.45-0.96) after spinal surgery. However, there were no significant differences in the incidence of postoperative nausea, the use of rescue pain medications, the number of rescue analgesics required, and the risk of discontinuation of patient-controlled analgesia between ramosetron and palonosetron (0.075 mg) or ondansetron (4 mg). There were no statistically significant differences in the risk of adverse events among the 3 medications. Conclusions: This meta-analysis of 3 RCTs showed that ramosetron reduced the risk of PONV and POV, limited the use of rescue antiemetics, reduced the postoperative pain score, and did not increase the risk of discontinuing patient-controlled analgesia compared with palonosetron or ondansetron after spinal surgery in 3 RCTs. Therefore, this meta-analysis indicates that ramosetron is an effective and well tolerated antiemetic that can be used to prevent PONV following spinal surgery in adult patients. PROSPERO identifier: CRD42020223596 (Curr Ther Res Clin Exp. 2022; 83:XXX-XXX)© 2022 Elsevier HS Journals, Inc.

Dynamic DNA Shortening by Telomere-Binding Protein Cdc13.

Telomeres are essential for chromosome maintenance. Cdc13 is a single-stranded telomeric DNA binding protein that caps telomeres and regulates telomerase function in yeast. Although specific binding of Cdc13 to telomeric DNA is critical for telomere protection, the detail mechanism how Cdc13-DNA complex protects telomere is unclear. Using two single-molecule methods, tethered particle motion and atomic force microscopy, we demonstrate that specific binding of Cdc13 on single-stranded telomeric DNA shortens duplex DNA into distinct states differed by ∼70-80 base pairs. DNA shortening by Cdc13 is dynamic and independent of duplex DNA sequences or length. Significantly, we found that Pif1 helicase is incapable of removing Cdc13 from the shortened DNA-Cdc13 complex, suggesting that Cdc13 forms structurally stable complex by shortening of the bound DNA. Together our data identified shortening of DNA by Cdc13 and provided an indication for efficient protection of telomere ends by the shortened DNA-Cdc13 complex.

Relationships of exercise timing with sleep, fatigue and rest-activity rhythms of lung cancer patients in Taiwan: An exploratory study.

OBJECTIVE: To explore the relationship of exercise timing (exercising close to bedtime, exercising in daylight and maintaining fixed exercise schedule) with sleep quality, fatigue and rest-activity rhythms among lung cancer patients in Taiwan. METHODS: Results from 43 lung cancer patients who were assigned and adhered to the exercise intervention in a 12-week randomised controlled trial were analysed. The MD Anderson Symptom Inventory and Pittsburgh Sleep Quality Index (PSQI) were administered. Actigraphs were used to assess rest-activity rhythms (in-bed less than out-of-bed dichotomy index, I < O) and objective sleep parameters, including total sleep time (TST) and sleep onset latency (SOL). RESULTS: Patients who exercised >4 hr before bedtime had significant improvement in fatigue (p < .0001), sleep quality (p = .012 for PSQI; p = .037 for TST; p = .017 for SOL) and rest-activity rhythms (p = .048 for I < O). Furthermore, patients who exercised with daylight exposure had a significant improvement in fatigue (p = .037) and sleep quality (p = .039 for PSQI). CONCLUSIONS: Exercising >4 hr before bedtime with daylight exposure is associated with improvement in rest-activity rhythms, sleep quality and fatigue in lung cancer patients. The causal relationship requires further investigation with experimental design.

Cocaine modifies brain lipidome in mice.

Lipids are predominant components of the brain and key regulators for neural structure and function. The neuropsychopharmacological effect of cocaine has been intensively investigated; however, the impact of cocaine on brain lipid profiles is largely unknown. In this study, we used a LC-MS-based lipidomic approach to investigate the impact of cocaine on brain lipidome in two mouse models, cocaine-conditioned place preference (CPP) and hyperlocomotor models and the lipidome was profoundly modified in the nucleus accumbens (NAc) and striatum respectively. We comprehensively analyzed the lipids among 21 subclasses across 7 lipid classes and found that cocaine profoundly modified brain lipidome. Notably, the lipid metabolites significantly modified were sphingolipids and glycerophospholipids in the NAc, showing a decrease in ceramide and an increase in its up/downstream metabolites levels, and decrease lysophosphatidylcholine (LPC) and lysophosphoethanolamine (LPE) and increase phosphatidylcholine (PC) and phosphatidylethanolamines (PE) levels, respectively. Moreover, long and polyunsaturated fatty acid phospholipids were also markedly increased in the NAc. Our results show that cocaine can markedly modify brain lipidomic profiling. These findings reveal a link between the modified lipidome and psychopharmacological effect of cocaine, providing a new insight into the mechanism of cocaine addiction.