[Research advances on the interaction between Pseudomonas aeruginosa bacteriophages and the host]

Pseudomonas aeruginosa is the most common pathogen of burn wound infection. It can encode a variety of virulence factors and is highly pathogenic, which can lead to poor prognosis and high mortality. In order to research a new method to combat Pseudomonas aeruginosa infection, researchers have observed a wide range of interactions between the bacteriophages and the host. Bacteriophages influence and even dominate the structure, movement, and metabolism of host bacteria through a variety of mechanisms, catalyze the evolution of the host, and are also an important factor in host environmental adaptability and pathogenicity. In this paper, the interaction between Pseudomonas aeruginosa bacteriophages and the host is reviewed from the single cell level and the population level. Understanding these interactions could provide new idea for the treatment of Pseudomonas aeruginosa clinical infections, provides a basis for future development of antimicrobial agents and guides the treatment of burn infections.

[Cold stress reduces lifespan and mobility of C. elegans by mediating lipid metabolism disorder and abnormal stress]

OBJECTIVE

To investigate the changes of lipid metabolism and stress response of adult C.elegans exposed to non-freezing low temperature and explore the possible mechanism.

METHODS

The survival rate and activity of adult C.elegans cultured at 20℃ or 4℃ were observed.Lipid metabolism of the cultured adult C.elegans was evaluated using oil red O staining and by detecting the expressions of the genes related with lipid metabolism.The effects of low temperature exposure on stress level of adult C.elegans were evaluated using mitochondrial fluorescence staining and by detecting the expression levels of stress-related genes and antioxidant genes at both the mRNA and protein levels.

RESULTS

The lifespan and activity of adult C.elegans exposed to low temperature were significantly reduced with decreased lipid accumulation (P < 0.05) and decreased expressions of genes related with fatty acid synthesis and metabolism (fat-5, fat-6, fat-7, fasn-1, nhr-49, acs-2 and aco-1;P < 0.01).Cold stress significantly increased the expressions of heat shock proteins hsp-70 and hsp16.2(P < 0.05) but lowered the number of mitochondria (P < 0.0001) and the expressions of atfs-1, sod-2, sod-3 and gpx-1(P < 0.05).Knockout of fat-5, nhr-49 or both fat-5 and fat-6 obviously enhanced the sensitivity of C.elegans to cold stress as shown by further reduced activity (P < 0.05) and reduced survival rate at 24 h (P < 0.0001) under cold stress.

CONCLUSION

Exposure to a low temperature at 4℃ results in lowered lipid metabolism of adult C.elegans accompanied by a decreased mitochondrial number and quality control ability, which triggers high expressions of stress-related genes and causes reduction of antioxidant capacity, thus callsing lowered activity and reduced lifespan of C.elegans.

Sodium Ions Affect Pyrraline Formation in the Maillard Reaction With Lys-Containing Dipeptides and Tripeptides

Advanced glycation end products (AGEs) are potentially-hazardous chemical compounds, produced by the Maillard reaction between reducing sugars and Lysine side-chain amino groups in proteins. AGEs are strongly associated with diabetes, Alzheimer's disease and atherosclerosis. Pyrraline, a sugar derivative of Lysine, is a major AGE and an established marker for the presence of dietary AGEs. In this study, the effects of NaCl and different dipeptide and tripeptide structures were compared on the formation of pyrraline-containing peptides and the glucose derivative 3-deoxyglucosone in the presence of glucose and at different NaCl concentrations. The physicochemical properties (polarizability, dipole moment, molecular volume and dissociation constant) and the thermodynamic properties of the peptides were determined. The amount of the pyrraline decreased significantly in the following order of peptides (at the same concentrations): Lys-Phe > Lys-Ala > Lys-Gly; Lys-Gly-Phe > Lys-Gly-Ala > Lys-Gly-Gly. The highest levels of both pyrraline and 3-deoxyglucosone occurred at 0.2 mol/L Na⁺. Sodium ions appear to alter the intramolecular electron density and charge distribution of the peptides and facilitate the reaction by stabilizing some of the intermediates in the reaction sequence.

Microstructure and mechanical properties of dissimilar NiTi and 304 stainless steel joints produced by ultrasonic welding

Superelastic NiTi alloy and 304 stainless steel (304 SS) were joined with a Cu interlayer by ultrasonic spot welding (USW) using different welding energy inputs. The surface morphology, interfacial microstructure, mechanical properties, and fracture mechanisms of the dissimilar NiTi/304 SS USWed joints were studied. The results showed that the surface oxidation intensified with increasing ultrasonic welding energy due to mutual rubbing between tools and sheets. The weld interface microstructure exhibited voids or unbonded zones at low energy inputs, while an intimate contact was established at the joining interface when applying a higher energy input of 750 J. With increasing energy input to 750 J, the weld interface shows two interfaces due to the behavior of plastic flow of Cu interlayer. The lap-shear load of the joints first increased, achieving a maximum value of ∼690 N at an energy input of 750 J, and then decreased with further increase in welding energy. Interfacial failure was observed at NiTi/Cu interface at all energy inputs, and no intermetallic compounds were found on the fracture surfaces of both the NiTi/Cu and Cu/304 SS interfaces.

[Effect of extracorporeal membrane oxygenation on pharmacokinetics of antimicrobial drugs: recent progress and recommendations]

Extracorporeal membrane oxygenation (ECMO) is an effective means to provide life support for patients with severe respiratory or heart failure. Existing studies have shown that ECMO may affect the metabolic process of some drugs by drug adsorption, increasing the apparent distribution volume and changing the clearance rate of the drugs. This review summarizes the recent progress in the studies of the effect of ECMO on the pharmacokinetics of antibacterial and antifungal drugs. For the antibacterial drugs, it is recommended that the dose of teicoplanin, imipenem, and linezolid should be increased during ECMO support, while the dose of azithromycin, ciprofloxacin, and tigecycline should not be modified for the time being. Currently studies on pharmacokinetic changes of antifungal drugs during ECMO support remain limited. Voriconazole can be absorbed substantially by ECMO due to its high lipophilicity, and higher doses are therefore recommended. The dose of micafungin also needs to be increased in children undergoing ECMO. However, current evidence concerning the dose of caspofungin and fluconazole are limited, and it is not clear whether the routine dose should be adjusted during ECMO support.

Glycosylated hemoglobin levels and the risk for contrast-induced nephropathy in diabetic patients undergoing coronary arteriography/percutaneous coronary intervention

Backgrounds

Diabetes mellitus is an independent risk factor for Contrast-induced nephropathy (CIN) in patients undergoing Coronary arteriography (CAG)/percutaneous coronary intervention (PCI). Glycosylated hemoglobin (HbA1c) is the gold standard to measure blood glucose control, which has important clinical significance for evaluating blood glucose control in diabetic patients in the past 3 months. This study aimed to assess whether preoperative HbA1c levels in diabetic patients who received CAG/PCI impacted the occurrence of postoperative CIN.

Methods

We reviewed the incidence of preoperative HbA1c and postoperative CIN in 670 patients with CAG/PCI from January 1, 2020 to October 30, 2020 and divided the preoperative HbA1c levels into 5 groups. Blood samples were collected at admission, 48 h and 72 h after operation to measure the Scr value of patients. Categorical variables were compared using a chi-square test, and continuous variables were compared using an analysis of variance. Fisher’s exact test was used to compare the percentages when the expected frequency was less than 5. Univariable and multivariable logistic regression analysis was used to exclude the influence of confounding factors, and P for trend was used to analyze the trend between HbA1c levels and the increased risk of CIN.

Results

Patients with elevated HbA1c had higher BMI, FBG, and LDL-C, and they were more often on therapy with hypoglycemic agents, Insulin and PCI. They also had higher basal, 48 h and 72 h Scr. The incidence of CIN in the 5 groups of patients were: 9.8, 11.9, 15.2, 25.3, 48.1%. (p < 0.0001) The multivariate analysis confirmed that in the main high-risk subgroup, patients with elevated HbA1C levels (≥8.8%) had a higher risk of CIN disease. Trend test showed the change of OR (1.000,1.248,1.553,2.625,5.829).

Conclusions

Studies have shown that in diabetic patients undergoing CAG/PCI, elevated HbA1c is independently associated with the risk of CIN, and when HbA1c > 9.5%, the incidence of CIN trends increase. Therefore, we should attach great importance to patients with elevated HbA1c at admission and take more active measures to prevent CIN.

[Visual analysis of research progress on emotional labor of medical staff in China]

Objective: To summarize the research progress of medical emotional labor in China, and provide data reference for medical workers in the field of emotional labor. Methods: In March 2020, we searched the research content of emotional labor of medical workers through CNKI system, and analyzed it by using CiteSpace software. We visualized the topic of emotional labor of medical workers by using the knowledge map formed by keyword co-occurrence and keyword clustering, as well as the emergent words and time zone map. The analysis contents include the basic information characteristics of the selected literature, research hotspots and topics, research trends and frontiers. Results: The first related literature was published in 2008, and 126 related literatures were retrieved. Research hotspots include 'emotional labor', 'nurse', 'work burnout', 'medical staff' and 'work satisfaction', etc. Topics can be divided into three categories: research objects, variables affecting factors and medical workplace. There are 24 emergent words. In 2008, 2011, 2013, and 2015, important turning points for research changes exist. Conclusion: In the future, researchers in China can try to broaden the scope of medical subjects and influencing factors, etc., and be closely linked to the results of existing studies.

PARP inhibitor niraparib as a radiosensitizer promotes antitumor immunity of radiotherapy in EGFR-mutated non-small cell lung cancer

BACKGROUND

Poly-(ADP-Ribose)-Polymerase inhibitors (PARPi) were reported as radiosensitizers in non-small cell lung cancer (NSCLC) with wide-type epidermal growth factor receptor (EGFR), but the effects of radiation combined with PARPi were not investigated in EGFR-mutated NSCLC. Moreover, the underlying mechanisms were not well examined. This study aimed to study the efficacy of radiation combined with niraparib in EGFR-mutated NSCLC and explore their influence on the immune system.

METHODS

Clone formation and apoptosis assay were conducted to explore the effects of niraparib and radiation. Immunofluorescence was conducted to detect the double-strand DNA breaks. Real-time PCR and immunoblotting were employed to evaluate the activation of STING/TBK1/TRF3 pathway and the expression levels of interferon β, CCL5 and CXCL10. Immunocompetent mice model bearing with subcutaneous Lewis lung cancer was established to confirm the results in vivo.

RESULTS

Niraparib and radiation were synergistic to inhibit tumor both in vitro and in vivo. Radiation plus niraparib could activate anti-tumor immunity, which appeared as increased CD8⁺ T lymphocytes and activated STING/TBK1/IRF3 pathway.

CONCLUSION

PARPi not only as a radiosensitizer inhibited EGFR-mutated NSCLC tumor growth, but also cooperated with radiation to promote anti-tumor immune responses.

Effect of Polyphenols on Cognitive Function: Evidence from Population-Based Studies and Clinical Trials

Due to progressive population aging, a new dementia case occurs at every 3 seconds, placing a heavy burden of disease. Identifying potential risk or preventive factors is emphasized owing to a lack of effective treatment for dementia. There has been emerging evidence on the link of certain dietary components, particularly polyphenols, to brain wellness and cognitive outcomes. Findings from animal and in vitro studies appear more consistent and conclusive. However, such an association has not been investigated in depth in human beings. In this review, we examined studies on the effect of dietary polyphenols (including flavonoids, curcumin, and resveratrol) on cognitive function. Intervention in early stages of dementia/Alzheimer's disease might be a target to slow down age-related cognitive decline before disease onset. We summarized 28 epidemiological studies (8 cross-sectional and 20 cohort studies) and 55 trials in this review. Preliminary evidence from epidemiological data provides the necessity for intervention trials, even though the measures of polyphenol intake tend to be less precise. Clinical trials are in favor of the role of some polyphenols in benefiting specific domains of cognition. This review also describes the divergence of results and current limitations of research in this field.