Characterization of linezolid- and methicillin-resistant coagulase-negative staphylococci in a tertiary hospital in China.

BACKGROUND: Recently, linezolid-resistant staphylococci have become an emerging problem worldwide. Understanding the mechanisms of resistance, molecular epidemiology and transmission of linezolid-resistant CoNS in hospitals is very important. METHODS: The antimicrobial susceptibilities of all isolates were determined by the microdilution method. The resistance mechanisms and molecular characteristics of the strains were determined using whole-genome sequencing and PCR. RESULTS: All the strains were resistant to oxacillin and carried the mecA gene; 13 patients (36.1%) had prior linezolid exposure. Most S. epidermidis and S. hominis isolates were ST22 and ST1, respectively. MLST typing and evolutionary analysis indicated most linezolid-resistant CoNS strains were genetically related. In this study, we revealed that distinct CoNS strains have different mechanisms of linezolid resistance. Among ST22-type S. epidermidis, acquisition of the T2504A and C2534T mutations in the V domain of the 23 S rRNA gene, as well as mutations in the ribosomal proteins L3 (L101V, G152D, and D159Y) and L4 (N158S), were linked to the development of linezolid resistance. In S. cohnii isolates, cfr, S158Y and D159Y mutations in the ribosomal protein L3 were detected. Additionally, emergence of the G2576T mutation and the cfr gene were major causes of linezolid resistance in S. hominis isolates. The cfr gene, G2576T and C2104T mutations, M156T change in L3 protein, and I188S change in L4 protein were found in S. capitis isolates. CONCLUSION: The emergence of linezolid-resistant CoNS in the environment is concerning because it involves clonal dissemination and frequently coexists with various drug resistance mechanisms.

Antimicrobial Peptides Targeting Streptococcus mutans: Current Research on Design, Screening and Efficacy.

Antimicrobial peptides (AMPs) are small-molecule peptides that play a vital role in the nonspecific immune defense system of organisms. They mainly kill microorganisms by physically destroying the cell membrane and causing the leakage of contents. AMPs have attracted much attention as potential alternatives to antibiotics due to their low susceptibility to resistance. Streptococcus mutans (S. mutans) is one of the main causative agents of human dental caries. The design, screening, and efficacy evaluation of AMPs targeting S. mutans offer new possibilities for the prevention and treatment of oral diseases, especially dental caries, in the future. This article reviews AMPs from different sources that have inhibitory effects on S. mutans, discusses the mechanism of action of AMPs against S. mutans biofilms, and focuses on the research progress of screening methods, design modification, and biological activity evaluation of AMPs. We hope to provide insights and reference value for the development of new biologics.

Aptasensors with palladium nanoparticle-modified hemin-containing metal-organic frameworks as the signal marker for detection of exosomes.

Zr-metal-organic frameworks (Zr-MOFs) have received increasing interest for their use as the signal marker in the development of sandwich-structured aptasensors for the detection of exosomes. However, Zr4+ ions of the Zr-MOFs can interact with not only the exosomes, but also the aptamers, leading to possible false positives and a large background response. In the present study, we report for the first time aptasensors with Pd nanoparticle (NP)-decorated and hemin-embedded UiO-66 MOFs serving as the signal amplification marker to eliminate false positives and decrease the background response of aptasensors. To construct aptasensors for detection of exosomes, CD63-specific aptamers were tethered onto magnetic Fe3O4 particles coated with polydopamine (PDA) and UiO-66-NH2 using glutaraldehyde crosslinking for capturing the exosomes. To prepare highly catalytic Zr-MOF-based signal markers, UiO-66 MOFs were modified with hemin followed by Pd NPs. The as-prepared Pd-decorated hemin-embedded MOFs showed high catalytic activity towards the chromogenic oxidation reaction of TMB by H2O2. Moreover, the decoration with Pd NPs led to the change of the surface charge state of the catalytic hemin-embedded UiO-66 MOFs from positive to negative, weakening the interaction between the signal marker and the negatively charged aptamers. Therefore, the as-prepared aptasensors showed an improved sensing performance towards exosomes with a linear concentration range from 4.28 × 102 to 4.28 × 105 and a limit of detection (LOD) of 86.2 particles per µL. The as-prepared aptasensors also showed high sensitivity and selectivity to the exosomes from different origins including the HeLa cell line and MCF-7 cell line.

Tanshinone IIA changed the amniotic fluid volume and regulated expression of AQP1 and AQP3 in amniotic epithelium cells: a promising drug treating abnormal amniotic fluid volume.

BACKGROUND: Many studies have confirmed the association of aquaporins (AQPs) with abnormal amniotic fluid volume (AFV). In our previous experiments, we found that Tanshinone IIA was able to regulate the expression of AQP1 and AQP3. However, the exact mechanism by which Tanshinone IIA regulates AQPs protein expression and its effect on AFV remains unclear. The purpose of this study was to investigate the effects of Tanshinone IIA on AFV and the possible molecular mechanism of regulation of AQP1 and AQP3. METHODS: The expression of AQPs protein in the amniotic membranes was compared between pregnant women with normal pregnancy and those with isolated oligohydramnios. The AQP1 knockout (AQP1-KO) mice and wild-type (WT) mice were treated with saline or Tanshinone IIA (10 mg/kg) at 13.5GD and 16.5GD. Human amniotic epithelium cells (hAECs) from pregnant women with normal AFV and isolated oligohydramnios were incubated with 35 µmmol/L Tanshinone IIA or 25 mmol/L LiCl [inhibitor of glycogen synthetic kinase 3ß (GSK-3ß)]. The protein expressions of AQPs, GSK-3ß, phospho-GSK-3ß (Ser9) in fetal membranes of mice and human amniotic epithelium cells were detected by western blotting. RESULTS: The expression of AQP1 protein in the amniotic membrane of isolated oligohydramnios was increased compared with normal pregnancy. The AFV in AQP1-KO mice is higher than that in WT mice. In wild-type mice, AFV in Tanshinone IIA group was significantly higher than that in control group, and AQP1 protein expression was significantly lower than that in control group, but in AQP1 knockout mice, Tanshinone IIA reduced amniotic fluid volume and AQP3 protein expression at 16.5GD. Tanshinone IIA reduced AQP1, AQP3 and p-GSK-3ß (Ser9) protein expression in normal hAECs, and this effect was inhibited by LiCl. In hAECs with oligohydramnios, the down-regulation of AQP1 and up-regulation of AQP3 by Tanshinone IIA was independent of GSK-3ß signaling pathway. CONCLUSIONS: Tanshinone IIA may increase AFV in normal pregnancy by downregulating AQP1 protein expression in the fetal membranes, which may be associated with p-GSK-3ß signaling pathway. But a larger AFV in AQP1-KO mice was significantly attenuated by Tanshinone IIA, which may be related to AQP3. Tanshinone IIA is a promising drug for the treatment of amniotic fluid abnormality.

Case report: Long-term clinical benefit of pyrotinib therapy following trastuzumab resistance in HER2-amplification recurrent mucinous ovarian carcinoma.

Advanced or recurrent mucinous carcinoma of the ovary minimally responds to current cytotoxic treatments and has a poor prognosis. Despite multimodal treatment with chemotherapy and surgery, most patients ultimately progress and require palliative systemic therapy. Anti-HER2 therapy has been demonstrated to be an effective strategy for the treatment of HER2-positive breast cancer. However, the role of anti-HER2 therapy in ovarian cancer remains largely unknown. Here, we report the case of a young woman with FIGO Stage IIIc recurrent mucinous ovarian carcinoma (MOC) who developed trastuzumab resistance and disease progression following cross-treatment with trastuzumab combined with pertuzumab. HER2 amplification was discovered using next-generation sequencing (NGS). The patient then received bevacizumab, and pyrotinib (an irreversible HER2 antagonist) plus capecitabine treatment, and achieved a long-term clinical benefit for 22 months. Pyrotinib combined with bevacizumab is a potential treatment for MOC patients who are heavily pretreated and harbor a HER2 amplification. Our case may provide valuable treatment information for patients with advanced or recurrent MOC.

Research progress on the molecular mechanisms of hepatic metastasis in lung cancer: a narrative review.

The liver is one of the most common sites of metastatic spread of lung cancer, and the process of metastasis is regulated by many factors. A number of genes, including multiple tumor suppressor 1 (mts1), p120 catenin, and CT45A1, increase the possibility of hepatic metastasis in lung cancer, whereas Tip30/CC3, CUL5, and SOCS3 expression in lung tumors inhibit tumor metastasis. microRNAs (miRNAs), such as miRNA-126, miRNA-338, and miRNA-218, can affect the metastasis of lung cancer cells to the liver. The D114-Notch signaling pathway can inhibit liver metastasis in small cell lung cancer. Serum tumor markers cytokeratin 19 fragment antigen 21-1 and neuron-specific enolase (NSE) are closely related to the risk of hepatic metastasis in lung cancer. Based on previously published literature, we found that the metastasis and invasion of lung cancer to the liver are determined by molecular factors. Therefore, the selective identification and intervention of these erroneous signals can predict early lung cancer metastasis to the liver. In this review article, we describe the mechanisms and influencing factors (genes, signal pathways, chemicals, proteins, miRNAs) of hepatic metastasis in lung cancer. We hope to provide a summary of the evidence for the mechanisms by which related genes or proteins affect the malignancy of liver metastasis from lung cancer so that doctors and researchers can improve treatment options.

Expression and Regulation of Aquaporins in Pregnancy Complications and Reproductive Dysfunctions.

Aquaporins (AQPs), small hydrophobic integral membrane proteins, mediate rapid transport of water and small solutes. The abnormal expressions of AQPs are associated with pregnancy complications and reproductive dysfunctions, including preeclampsia, gestational diabetes mellitus, tubal ectopic pregnancy, intrahepatic cholestasis of pregnancy, preterm birth, chorioamnionitis, polyhydramnios, and oligohydramnios, thus resulting in adverse pregnancy outcomes. This review explains the alterations of AQPs in pregnancy complications and reproductive dysfunctions and summarizes the molecular mechanisms involved in the regulations of AQPs by drugs such as oxytocin, polychlorinated biphenyls, all-trans-retinoic acid, salvia miltiorrhiza, and insulin, or other factors such as oxygen and osmotic pressure. All the research provides evidence that AQPs could be the new therapeutic targets of pregnancy-related diseases.

The Endocrine Disruption of Prenatal Phthalate Exposure in Mother and Offspring.

Phthalates are a group of ubiquitous synthetic endocrine-disrupting chemicals. Fetal and neonatal periods are particularly susceptible to endocrine disorders, which prenatal exposure to phthalates causes. There is increasing evidence concerning the potential endocrine disrupting for phthalate exposure during pregnancy. This article aims to review the endocrine impairment and potential outcomes of prenatal phthalate exposure. Prenatal exposure phthalates would disrupt the levels of thyroid, sex hormone, and 25-hydroxyvitamin D in pregnant women or offspring, which results in preterm birth, preeclampsia, maternal glucose disorders, infant cryptorchidism, infant hypospadias, and shorter anogenital distance in newborns, as well as growth restriction not only in infants but also in early adolescence and childhood. The relationship of prenatal phthalate exposure with maternal and neonatal outcomes in human beings was often sex-specific associations. Because of the potentially harmful influence of prenatal phthalate exposure, steps should be taken to prevent or reduce phthalate exposure during pregnancy.

Timing of umbilical cord clamping and neonatal jaundice in singleton term pregnancy.

BACKGROUND: Delayed cord clamping was not adopted widely in China because of the potential effect of neonatal hyperbilirubinemia, jaundice and polycythemia, and the optimal cord clamping time remained controversial. AIM: To assess the effect of delayed cord clamping versus early cord clamping on neonatal jaundice for term infants. STUDY DESIGN: This retrospective study included 1981 mother-infant pairs, who were assigned to early cord clamping groups (n = 1005) and delayed cord clamping group (n = 949). The delayed cord clamping included three subgroups (30-60 s, 61-90 s, 91-120 s). The main outcomes were transcutaneous bilirubin levels at 0 to 4 days of age, the rate of jaundice requiring phototherapy, the neonatal hematological status at 1 to 3 days after birth. RESULTS: Compared with the early cord clamping group, the neonatal transcutaneous bilirubin level did not differ and the neonatal hematological status (hemoglobin and hematocrit levels) were improved in combined and three subgroups of delayed cord clamping group. Increasing the duration of cord clamping from 90 s to 120 s did not result in further increases in hemoglobin and hematocrit levels but led to a trend towards a higher risk of neonatal jaundice requiring phototherapy and neonatal polycythemia. CONCLUSIONS: Delayed cord clamping for <90 s in healthy term infants may not only improve the early hematological status of newborns but also avoid excessive neonatal jaundice requiring phototherapy.

Early versus delayed umbilical cord clamping on maternal and neonatal outcomes.

PURPOSE: Policies for timing of cord clamping varied from early cord clamping (ECC) in the first 30 s after birth, to delayed cord clamping (DCC) in more than 30 s after birth or when cord pulsation has ceased. DCC, an inexpensive method allowed physiological placental transfusion. The aim of this article is to review the benefits and the potential harms of early versus delayed cord clamping. METHODS: Narrative overview, synthesizing the findings of the literature retrieved from searches of computerized databases. RESULTS: Delayed cord clamping in term and preterm infants had shown higher hemoglobin levels and iron storage, the improved infants' and children's neurodevelopment, the lesser anemia, the higher blood pressure and the fewer transfusions, as well as the lower rates of intraventricular hemorrhage (IVH), chronic lung disease, necrotizing enterocolitis, and late-onset sepsis. DCC was seldom associated with lower Apgar scores, neonatal hypothermia of admission, respiratory distress, and severe jaundice. In addition, DCC was not associated with increased risk of postpartum hemorrhage and maternal blood transfusion whether in cesarean section or vaginal delivery. DCC appeared to have no effect on cord blood gas analysis. However, DCC for more than 60 s reduced drastically the chances of obtaining clinically useful cord blood units (CBUs). CONCLUSION: Delayed cord clamping in term and preterm infants was a simple, safe, and effective delivery procedure, which should be recommended, but the optimal cord clamping time remained controversial.

Physiological and pathological impact of AQP1 knockout in mice.

Aquaporin 1 (AQP1) is a glycoprotein responsible for water passive transport quickly across biological membrane. Here, we reviewed the structural and functional impacts of AQP1 knockout (AQP1-KO) in animal or cell culture models. AQP1 gene deletion can cause a large number of abnormalities including the disturbance in epithelial fluid secretion, polyhydramnios, deficiency of urinary concentrating function, and impairment of pain perception. AQP1-KO mice also displayed aberrations of cardiovascular, gastrointestinal and hepatobiliary, and kidney functions as well as placenta and embryo development. Moreover, AQP1-KO perturbed tumor angiogenesis and led to reduced brain injury upon trauma. On the cellular level, AQP1-KO caused neuroinflammation, aberrant cell proliferation and migration, and macrophages infiltration. Mechanistic studies confirmed that AQP1 gene products regulate the secretory function and participated in balancing the osmotic water flux across the peritoneal membrane. The available data indicated that AQP1 might serve as a potential target for developing novel therapeutic approaches against diverse human diseases.