Intracellular activity of antimicrobial compounds used for Staphylococcus aureus nasal decolonization

Background

Staphylococcus aureus is able to invade mammalian cells during infection and was recently observed inside nasal mucosa of healthy carriers.

Objectives

To determine the intracellular activity of antimicrobial compounds used for decolonization procedures using a cell model mimicking S. aureus nasal epithelium invasion.

Patients and methods

HaCaT cells and human nasal epithelial cells (HNECs) recovered from nasal swabs of S. aureus carriers were visualized by confocal laser scanning microscopy to detect intracellular S. aureus cells. An HaCaT cell model, mimicking S. aureus internalization observed ex vivo in HNECs, was used to assess the intracellular activity against S. aureus of 21 antimicrobial compounds used for nasal decolonization, including mupirocin and chlorhexidine.

Results

HaCaT cells and HNECs were found to internalize S. aureus with the same focal pattern. Most antimicrobial compounds tested on HaCaT cells were shown to have weak activity against intracellular S. aureus. Some systemic antimicrobials, including fusidic acid, clindamycin, linezolid, minocycline, ciprofloxacin, moxifloxacin, rifampicin and levofloxacin, reduced S. aureus intracellular loads by 0.43-1.66 log cfu/106 cells compared with the control (P < 0.001). By contrast, mupirocin and chlorhexidine reduced the S. aureus intracellular load by 0.19 and 0.23 log cfu/106 cells, respectively.

Conclusions

These data indicate that most of the antimicrobial compounds used for nasal decolonization, including mupirocin and chlorhexidine, exhibit weak activity against intracellular S. aureus using the HaCaT cell model. This work emphasizes the need to better understand the role of the S. aureus intracellular reservoir during nasal colonization in order to improve decolonization procedures.

Comparison of microRNAs in adipose and muscle tissue from seven indigenous Chinese breeds and Yorkshire pigs

Elucidation of the pig microRNAome is essential for interpreting functional elements of the genome and understanding the genetic architecture of complex traits. Here, we extracted small RNAs from skeletal muscle and adipose tissue, and we compared their expression levels between one Western breed (Yorkshire) and seven indigenous Chinese breeds. We detected the expression of 172 known porcine microRNAs (miRNAs) and 181 novel miRNAs. Differential expression analysis found 92 and 12 differentially expressed miRNAs in adipose and muscle tissue respectively. We found that different Chinese breeds shared common directional miRNA expression changes compared to Yorkshire pigs. Some miRNAs differentially expressed across multiple Chinese breeds, including ssc-miR-129-5p, ssc-miR-30 and ssc-miR-150, are involved in adipose tissue function. Functional enrichment analysis revealed that the target genes of the differentially expressed miRNAs are associated mainly with signaling pathways rather than metabolic and biosynthetic processes. The miRNA-target gene and miRNA-phenotypic traits networks identified many hub miRNAs that regulate a large number of target genes or phenotypic traits. Specifically, we found that intramuscular fat content is regulated by the greatest number of miRNAs in muscle tissue. This study provides valuable new candidate miRNAs that will aid in the improvement of meat quality and production.

Response of AMP-activated protein kinase and lactate metabolism of largemouth bass (Micropterus salmoides) under acute hypoxic stress

To study adaptation of largemouth bass (Micropterus salmoides) to hypoxic stress, we investigated physiological responses and lactate metabolism of the fish under acute hypoxia. The objectives of this study were to (a) observe changes in glucose, glycogen, and lactate content; (b) detect the activity of lactate dehydrogenase (LDH) in serum, brain, heart, and liver tissues; and (c) quantify the dynamic gene expression of AMP activated protein kinase alpha (AMPKα), hypoxia-inducible factor-1 alpha (HIF-1α), monocarboxylate transporter 1 (MCT1), monocarboxylate transporter 4 (MCT4), and lactate dehydrogenase-a (LDHa) following exposure to hypoxia. The fish were subjected to two hypoxia stresses (dissolved oxygen [DO] 1.20 ± 0.2 mg/L and 3.50 ± 0.3 mg/L, respectively) for 24 h. Our results showed that hypoxic stress significantly increased the decomposition of liver glycogen and significantly increased the concentration of blood glucose; however, the muscle glycogen content was not significantly decreased, which indicates that liver glycogen was the main energy source under acute hypoxia. Moreover, hypoxia led to accumulation of a large amount of lactic acid in tissues, possibly due to the activity of lactic acid dehydrogenase, but this process was delayed in the heart and brain relative to the liver. Additionally, hypoxia induced the expression of AMPKα, HIF-1α, MCT1, MCT4, and LDHa, suggesting that glycometabolism had switched from aerobic to anaerobic. Our results contribute to a better understanding of the molecular mechanisms of the response to hypoxia in largemouth bass.

Cortical bone resorption of fibular bone after maxillary reconstruction with a vascularized fibula free flap: a computed tomography imaging study

This study was performed to evaluate the cortical bone resorption of fibular bone after maxillary reconstruction with a fibula free flap. A total of 35 patients with maxillary defects that were repaired using a fibula flap (62 fibula segments) between January 2011 and January 2016 were enrolled. Computed tomography (CT) images taken 1 week and 1 year postoperative were used to evaluate cortical bone resorption. The 62 fibula segments were measured on four different surfaces in the CT images. At 1 week, the thickness of the cortical bone was 2.57 ± 0.58 mm, 2.72 ± 0.46 mm, 3.84 ± 0.98 mm, and 4.36 ± 0.90 mm for the exterior, interior, superior, and inferior sides, respectively. At approximately 1 year, the cortical bone thickness was significantly reduced to 2.00 ± 0.65 mm (P <  0.01), 2.25 ± 0.60 mm (P <  0.01), 3.37 ± 0.90 mm (P <  0.01), and 2.96 ± 0.84 mm (P <  0.01) for the exterior, interior, superior, and inferior sides, respectively. The cortical bone thickness of fibular bone is significantly reduced 1 year after the restoration of maxillary defects with a fibula free flap, most significantly on the inferior side.

[A study on the status and problem countermeasures of key occupational disease monitoring in Shandong, China, from 2015 to 2017]

Objective: To analyze the completion status, monitoring results, and existing problems of key occupational disease monitoring in Shandong, China, from 2015 to 2017, and to provide reference materials for improving monitoring quality and carrying out occupational disease prevention and control. Methods: The monitoring situation including project coverage, data collection, monitoring results, and monitoring quality of key occupational diseases in Shandong from 2015 to 2017 were described and comparatively analyzed. Results: In the past three years, the uncoverage rate of monitored counties (38.69% in 2015, 10.95% in 2016, and 5.11% in 2017) , the non-work rate of occupational health examination institutions (41.67% in 2015, 18.02% in 2016, and 8.72% in 2017) , and the non-work rate of occupational disease diagnosis institutions (42.31% in 2015, 38.46% in 2016, and 38.46% in 2017) in Shandong decreased year by year. The number of institutions with key occupational hazard factors reported to the safety supervision and management department increased year by year (it was 24140 in 2017, with an increase of 40.50% compared with 2016 and an increase of 114.62% compared with 2015) ; the key occupational hazard factors in enterprises were mainly noise (72.76%) , followed by benzene, silica dust, and coal dust. The number of workers exposed to key occupational hazard factors reported to the safety supervision and management department increased year by year; in 2017, it was 729245, with an increase of 39.78% compared with 2016 and an increase of 84.81% compared with 2015. The ratio of people exposed to key occupational hazard factors identified by the medical examination to the total people in the safety supervision system in a year decreased year by year (40.87% in 2015, 23.86% in 2016, and 17.95% in 2017) . Conclusion: In Shandong, the supervision of enterprises with key occupational hazard factors and the responsibility of enterprise protection should be strengthened. The occupational health examination rate of workers should be improved. It is suggested that we should carry out the special investigations and occupational health risk assessment for key enterprises and key populations.

[Characteristics of distribution and changes of telomere length in human]

OBJECTIVE

To explore the relationship between telomere length changes and age, and to provide data and reference for further study of geriatric medical problems.
 Methods: The healthy people over 20 years old were chosen as subject from several hospitals by random sampling method, and their peripheral blood samples were collected. The relative length of telomere was detected by quantitative real-time PCR, and the relationship between age and telomere length was analyzed by statistical software.
 Results: A total of 1 022 samples were obtained. There were significant differences in the relative telomere length among different age groups (F=21.492, P<0.001). Telomere length and age showed negative correlation (r=-0.325, P<0.001), the regression equation was y=-0.008x+1.772 (x for age, y for the average telomere length, P<0.001).
 Conclusion: The telomere length for peripheral blood leukocytes in healthy people varies between different age groups, suggesting that telomere length gradually decreases with age.

Parathyroid hormone-stimulation of Runx2 during osteoblast differentiation via the regulation of lnc-SUPT3H-1:16 (RUNX2-AS1:32) and miR-6797-5p

Parathyroid hormone (PTH) acts as a regulator of calcium homeostasis and bone remodeling. Runx2, an essential transcription factor in bone, is required for osteoblast differentiation. Noncoding RNAs such as long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) play crucial roles in regulating gene expression in osteoblasts. In this study, we investigated the effects of PTH on osteoblast differentiation via Runx2, lncRNA, and miRNA expression in human bone marrow stromal cells (hBMSCs) and human osteoblastic cells (MG63). PTH-treatment of hBMSCs for 24 h, 7 days, and 14 days stimulated Runx2 mRNA expression. Using bioinformatics tools, we identified 17 lncRNAs originating from human Runx2 gene. Among these, lnc-SUPT3H-1:16 (RUNX2-AS1:32) expression was highly up-regulated by the 7 d PTH-treatment in hBMSCs. We also identified miR-6797-5p as the putative target of lnc-SUPT3H-1:16 and Runx2 using bioinformatics tools. PTH-treatment increased the expression of miR-6797-5p in hBMSCs, and overexpression of miR-6797-5p decreased osteoblast differentiation in MG63 cells, suggesting a role for lnc-SUPT3H-1:16 as sponge molecule. A luciferase gene reporter assay identified direct targeting of miR-6797-5p with lnc-SUPT3H-1:16 and 3'UTR Runx2 in MG63 cells. Thus, PTH stimulated the expression of lnc-SUPT3H-1:16, miR-6797-5p and Runx2, and due to the sponging mechanism of lnc- SUPT3H-1:16 towards miR-6797-5p, Runx2 was protected, resulting in the promotion of osteoblast differentiation.

[Evaluation of the aging status and distribution characteristics for male population by three-dimensional human aging scale]

OBJECTIVE

To investigate the ageing status for male population aged or over 20 years old in urban communities, clarifying their distribution characteristics and rules, and to provide reference for aging research.
 Methods: A total of 1 120 men aged or over 20 years old in Nanchang were obtained by stratified sampling, and the aging scale was measured in 9 groups. The distribution characteristics of aging scores were analyzed by normality test, variance analysis, and linear correlation.
 Results: The total score of aging and the scores of physiological, psychological, and physiological dimensions were 54.01±9.24, 32.33±7.54, 14.66±1.64, and 7.02±1.16, respectively. The scores were positively correlated with age. The total score curve of aging was significantly increased in the 25-<30 and 30-<40, 65-<70 and 70-<75 years old groups. The physiological dimension curve was similar to the total score curve. The psychological dimension curve was more pronounced at 55-<60 and 60-<65 years old groups. The social dimension curve raised slowly and smoothly at all ages.
 Conclusion: The total score and the scores for all dimensions of male physiological-psycho-sociological increase with age; and changes near the age group of 55-<60 and 60-<65 are obvious, providing reference for the understanding of male aging.

Benefits of Etoposide Maintenance Therapy for Patients With Extensive SCLC Who Experienced PR/CR/SD After 4-6 Cycles of First-Line Chemotherapy With Etoposide Plus Cisplatin/Carboplatin

Background: The clinical remission period of small cell lung cancer was shorter after the first-line treatment. Aim: To observe whether oral etoposide maintenance therapy can improve the progression-free survival (PFS) in patients with lung cancer who experienced complete remission (CR), partial remission (PR), and disease stabilization (SD) after 4-6 cycles of first-line chemotherapy with etoposide plus cisplatin/carboplatin. Methods: A retrospective analysis was performed on patients with ED-SCLC who were treated with etoposide (100 mg/d, iv.gtt days 1-5 with a cycle length of every 21 days) plus 4-6 cycles of cisplatin/carboplatin chemotherapy during the period from 1 January 2014 to 31 December 2016 at the Cancer Hospital affiliated with Zhengzhou University. All the patients were divided into 2 groups based on the criteria whether they had gone through maintenance therapy with etoposide: nonmaintained treatment group (NT), and maintenance treatment group (TH). The maintenance treatment group was further subdivided into the 25 mg subgroup (group A) and the 50 mg subgroup (group B) according to the maintenance dose. Analysis of 1-year progression-free survival (PFS) was conducted using the Kaplan-Meier method and Cox proportional hazards model. PFS1 was defined as the first day of first-line treatment until the disease progressed or the last follow-up time. PFS2 was defined as the first day of etoposide capsule treatment until disease progression or the last follow-up time. Results: A total of 85 patients were enrolled in this study; there were 50 patients in the NT group (58.8%) and 35 patients in the TH group (41.2%). In the TH group, there were 10 (28.6%) in the 25 mg subgroup (group A) and 25 (71.4%) in the 50 mg subgroup (group B). Detailed patient information and tumor-related parameters are shown in Table 1. For all patients, the median PFS1 in the first-line regimen with either the cisplatin or carboplatin group was 6.5 months (95% CI: 5.870-7.130) and 6.4 months (95% CI: 5.970-6.970) respectively ( P = 0.0551). Median progression-free survival for all patients and the median PFS for patients of the TH group were 6.5 months (95% CI: 6.138-6.861) and 7.2 months (95% CI: 6.702-7.698) respectively; the median PFS for the NT group, subgroup A, and subgroup B were 5.7 months (95% CI: 4.862-6.478), 6.7 months (95% CI: 6.390-7.010), and 7.4 months (95% CI: 6.386-8.474), respectively ( P = 0.0043). Median PFS2 was 2.400 months for maintenance treatment patients; the median PFS2 in the 25 mg and 50 mg groups was 2.100 months (95% CI 1.690-2.510 months) and 3.030 months (95% CI 1.937-4.123 months), respectively ( P = 0.0309). Conclusion: Use of etoposide capsules to maintain chemotherapy can significantly prolong the progression-free survival (PFS) of CR, PR, and SD in patients with extensive SCLC and improve 1-year survival; a 50-mg dose is better than 25 mg.