Development and Validation of a Risk Nomogram Model for Predicting Community-Acquired Pressure Injury Among the Older Adults in China: A Case-Control Study.

Purpose: A predictive model of community-acquired pressure injury (CAPI) was established and validated to allow the early identification of the risk of pressure injuries by family caregivers and community workers. Patients and Methods: The participants were hospitalized patients 65 years and older from two branches of a tertiary hospital in China, one for model training set and the other for validation set. This study was a case-control study based on hospital electronic medical records. According to the presence of pressure injury at admission, patients were divided into a case group and a control group. In the model training set, LASSO regression was used to select the best predictors, and then logistic regression was used to construct a nomogram. The performance of the model was evaluated by drawing the receiver operating characteristic curve (ROC) and calculating the area under the curve (AUC), calibration analysis, and decision curve analysis. The model used a 10-fold crossover for internal and external validation. Results: The study included a total of 20,235 subjects, including 11,567 in the training set and 8668 in the validation set. The prevalence of CAPI in the training and validation sets was 2.5% and 1.8%, respectively. A nomogram was constructed including eight variables: age ≥ 80, malnutrition status, cerebrovascular accidents, hypoproteinemia, respiratory failure, malignant tumor, paraplegia/hemiplegia, and dementia. The AUC of the prediction model in the original model, internal validation, and external validation were 0.868 (95% CI: 0.847, 0.890), mean 0.867, and 0.840 (95% CI: 0.807,03.873), respectively. The nomogram showed acceptable calibration and clinical benefit. Conclusion: We constructed a nomogram to predict CAPI from the perspective of comorbidity that is suitable for use by non-specialists. This nomogram will help family caregivers and community workers with the early identification of PI risks.

Effect of Multiple Doses of Intravenous Tranexamic Acid on Perioperative Blood Loss in Total Knee Arthroplasty: A Randomized Controlled Study.

OBJECTIVE: To identify the efficacy and safety of multiple doses of intravenous tranexamic acid (IV-TXA) following primary total knee arthroplasty (TKA) with a tourniquet. METHODS: This is a single-blind randomized controlled study that recruited osteoarthritis patients who had undergone primary unilateral TKA from May 2019 to May 2020 at our medical center. A total of 300 patients were randomly divided into three groups to receive: one dose (1 g) of IV-TXA before skin incision combined with one dose (1.5 g) of intra-articular tranexamic acid（IA-TXA) followed by a single dose of IV-TXA (1 g) for 3 h (group A); two doses of IV-TXA (1 g) for 3 and 6 h (group B); or three doses of IV-TXA (1 g) for 3, 6, and 12 h (group C) postoperatively. TKA with a tourniquet was performed by the same surgical team. The primary outcomes were total blood cell loss (TBL), hidden blood loss (HBL), maximum hemoglobin (Hb) drop, and transfusion rate. Secondary outcomes were levels of C-reactive protein (CRP) and D-dimer, and the incidence of postoperative complications. One-way analysis of variance, subgroup analysis, and multivariate correlation analysis were used to calculate the differences among the three groups. RESULTS: The study included 56 male and 244 female patients aged 60-80 years. The mean TBL, the mean HBL, and the maximum Hb drop in group C (471.2 ± 190.6 mL, 428.4 ± 190.3 mL, and 21.2 ± 3.8 g/L, respectively) were significantly lower than those in groups B (563.4 ± 224.6 mL, P = 0.030; 519.9 ± 226.4 mL, P = 0.033; and 23.2 ± 4.1 g/L, P = 0.001, respectively), and A (651.6 ± 254.1 mL, P < 0.001; 607.1 ± 254.3 mL, P < 0.001; and 25.1 ± 4.3 g/L, P < 0.001, respectively). No transfusions were required. The postoperative acute inflammatory reaction was less problematic for patients in Group C, and the incidence of thromboembolic events was similar among the groups (P > 0.05). In addition, there were positive correlations between the HBL and the tourniquet inflation time (r = 0.844, P < 0.001). Similarly, the level of CRP on POD1 (r = 0.393, P < 0.001) and POD3 (r = 0.149, P = 0.010), and the level of D-dimer on POD1 (r = 0.382, P < 0.001) were positively correlated with the HBL. CONCLUSION: Three doses of postoperative IV-TXA decreased blood loss and diminished the postoperative inflammatory and fibrinolytic response more than a single dose or two doses in elderly patients following TKA without increasing the incidence of adverse events.

A biomimetic peptide recognizes and traps bacteria in vivo as human defensin-6.

Using broad-spectrum antibiotics for microbial infection may cause flora disequilibrium, drug-resistance, etc., seriously threatening human health. Here, we design a human defensin-6 mimic peptide (HDMP) that inhibits bacterial invasion in vivo through mimicking the mechanisms of human defensin-6 with high efficiency and precision. The HDMP with ligand and self-assembling peptide sequence recognizes bacteria through ligand-receptor interactions and subsequently traps bacteria by an in situ adaptive self-assembly process and resulting nanofibrous networks; these trapped bacteria are unable to invade host cells. In four animal infection models, the infection rate was markedly decreased. Notably, administration of HDMP (5 mg/kg) nanoparticles increased the survival rate of mice with methicillin-resistant S. aureus bacteremia by as much as 100%, even more than that of vancomycin treatment (5 mg/kg, 83.3%)-treated group, the golden standard of antibiotics. This biomimetic peptide shows great potential as a precise and highly efficient antimicrobial agent.

Pb2+ adsorption by ethylenediamine-modified pectins and their adsorption mechanisms.

Ethylenediamine-modified pectins (EPs) with different degrees of amidation (DA) were prepared and characterized by Fourier Transform Infrared spectra (FTIR), elemental analysis, X-ray photoelectron spectroscopy (XPS). The prepared EPs were then used to remove Pb2+ from the aqueous solution. It was found that EPs with the highest DA (EP48) exhibited great removal efficiency of Pb2+ (≥94 %) at low concentrations of 40-80 mg/L. The zeta potential analysis showed that EP48 had the fastest increase in zeta potential when Pb2+ was continuously added and was the first to be electroneutralized. Particle size analysis further confirmed that EP48 was the first precipitated and formed a larger EP48-Pb2+ complex. The FTIR and XPS analyses indicated that Pb2+ was adsorbed via the ion exchange of carboxylic groups and chelation with acylamino and amino groups. These results suggested that the EP48 might be a promising adsorbent for the removal of low concentrations of Pb2+ in contaminated water.

Transformable Nanomaterials as an Artificial Extracellular Matrix for Inhibiting Tumor Invasion and Metastasis.

Tumor metastasis is one of the big challenges in cancer treatment and is often associated with high patient mortality. Until now, there is an agreement that tumor invasion and metastasis are related to degradation of extracellular matrix (ECM) by enzymes. Inspired by the formation of natural ECM and the in situ self-assembly strategy developed in our group, herein, we in situ constructed an artificial extracellular matrix (AECM) based on transformable Laminin (LN)-mimic peptide 1 (BP-KLVFFK-GGDGR-YIGSR) for inhibition of tumor invasion and metastasis. The peptide 1 was composed of three modules including (i) the hydrophobic bis-pyrene (BP) unit for forming and tracing nanoparticles; (ii) the KLVFF peptide motif that was inclined to form and stabilize fibrous structures through intermolecular hydrogen bonds; and (iii) the Y-type RGD-YIGSR motif, derived from LN conserved sequence, served as ligands to bind cancer cell surfaces. The peptide 1 formed nanoparticles (1-NPs) by the rapid precipitation method, owing to strong hydrophobic interactions of BP. Upon intravenous injection, 1-NPs effectively accumulated in the tumor site due to the enhanced permeability and retention (EPR) effect and/or targeting capability of RGD-YIGSR. The accumulated 1-NPs simultaneously transformed into nanofibers (1-NFs) around the solid tumor and further entwined to form AECM upon binding to receptors on the tumor cell surfaces. The AECM stably existed in the primary tumor site over 72 h, which consequently resulted in efficiently inhibiting the lung metastasis in breast and melanoma tumor models. The inhibition rates in two tumor models were 82.3% and 50.0%, respectively. This in vivo self-assembly strategy could be widely utilized to design effective drug-free biomaterials for inhibiting the tumor invasion and metastasis.

[Methane monooxygenases hydroxylase from a type II methanotroph: purification and physical-chemical properties].

Methanotrophs can catalyze hydroxylate of methane and some hydrocarbon. Which play an important role in mitigating global warming and have also potential significance for industrial applications or bioremediation. A high activity of hydroxylase, a crucial component in sMMO, from Methylosinus trichosporium IMV 3011 has been purified to homologues by using chromatographic techniques. The molecular weight of the hydroxylase determined by gel filtration is 201.3 kD, and SDS-PAGE showed that hydroxylase consists of three subunits(alpha beta gamma) with molecular weights of 58kD, 36kD and 23kD respectively, drawing a comparison both methods indicated that the hydroxylase is a homodimer with an (alpha beta gamma)2 configuration. Purified hydroxylase has a pI at 5.2 judged by thin layer isoelectric focusing. The purified hydroxylase contains 3.02 mol of iron per mol of protein. The stability pH for the hydroxylase in solution is 5.8-8.0 and the stability temperature is below 35 degrees C. The cells form show a long, bent, and rod-shaped with even surface observed by scanning electron microscopy.

An efficient and inexpensive catalyst system for the aza-Michael reactions of enones with carbamates.

A new strategy which uses very cheap FeCl3 as an effective catalyst in the presence of Me3SiCl has been developed for the conjugate addition of enones and chalcone with unactivated weakly nucleophilic carbamates.

Particulate methane monooxygenase from Methylosinus trichosporium is a copper-containing enzyme.

Particulate methane monooxygenase (pMMO) has been exfoliated and isolated from membranes of the Methylosinus trichosporium IMV 3011. It appears that the stability of pMMO in the exfoliation process is increased with increasing copper concentration in the growth medium, but extensive intracytoplasmic membrane formed under higher copper concentration may inhibit the exfoliation of active pMMO from membrane. The highest total activity of purified pMMO is obtained with an initial concentration of 6 microM Cu in the growth medium. The purified MMO contains only copper and does not utilize NADH as electron donor. Treatment of purified pMMO with EDTA resulted in little change in copper level, suggesting that the copper in the pMMO is tightly bound with pMMO.