Frontiers in Laboratory Medicine最新文献

Atherosclerosis is a chronic inflammatory disease, and multiple signaling pathways participate in its pathophysiological process. It has been generally recognized that macrophage autophagy is involved in the development of atherosclerosis. As a multifunctional ubiquitin-binding protein, p62/SQSTM1 participates in many core processes of autophagy in macrophages. Therefore, it is significant to investigate the role of p62 in atherosclerosis on the basis of autophagy theory. In this paper, we will review the latest research about p62 protein in atherosclerosis, in order to provide a reference for further understanding of the occurrence and development of atherosclerosis.

In this paper, we report the synthesis of hybrid silver nanostructures (AgNPs) based on an effective mixing of polyols with Polyvinylpyrrolidone (PVP) and Porphyrin molecules, in particular Protoporphyrin IX (PP). The combination of PVP and PP, which act as co-directing agents and favour the anisotropic growth of nanostructures, yields to very stable complexes for six months. The resulting hybrid silver nanoparticles have been further characterized by polarization modulation-infrared reflection-adsorption spectroscopy (PM-IRRAS), UV–Visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), revealing that the main role of Porphyrin molecules in the formation of silver nanostructures.

Gastric cancer (GC) is one of the leading causes of cancer-related death. The 5-year overall survival (OS) rate of patients is extremely low and to find a new marker is urgently needed. Increasing studies indicate that long noncoding RNAs (lncRNAs) are abnormally expressed in GC. However, the results of these studies were conflicting and inconclusive, especially in the aspects of tumor prognosis. Therefore, we performed a systematic review and meta-analysis to investigate the clinical values, including prognosis and clinicopathology of different lncRNAs in GC. A total of 38 studies including 34 on OS, 17 on disease-free survival (DFS), 1 on progression-free survival (PFS), 1 on disease-specific survival (DSS), and 34 on clinicopathological features were identified from the databases. Our results indicated that the levels of lncRNAs were associated with the OS (hazard ratios [HR] = 1.44, 95% confidence interval [95% CI] = 1.23–1.69, P < 0.001), PFS (HR = 2.32, 95% CI = 1.10–5.28, P = 0.001) and DSS (HR = 2.65, 95% CI = 1.53–3.60, P = 0.009). However, there was no relationship between lncRNAs and DFS (HR = 1.25, 95% CI = 0.90–1.74, P = 0.11). Moreover, lncRNAs were related to lymph node metastasis (odds ratios [OR] = 1.67, 95% CI = 1.21–2.31, P = 0.002) and TNM (OR = 1.93, 95% CI = 1.27–2.92, P < 0.001). In conclusion, our present meta-analysis indicated that lncRNAs could function as potential prognostic markers in GC.

Objective

To assess the China-made equipment Mindray BS-2000M biochemical analyzer and explore the comparability between the results of the sixteen test parameters detected by Mindray BS-2000M biochemical analyzer and by imported equipment Roche cobas702 automatic biochemical analyzer.

Methods

In line with the American Clinical Laboratory Standardization Committee (NCCLS) document EP9-A2, Switzerland Roche cobas702 biochemical analyzer was used as a comparison system, while the Mindray BS-2000M served as an experimental system. Sixteen biochemical parameters from forty cases at different levels were tested at the same time. The correlation coefficient(r), linearity regression equation and absolute deviation (SE) and relative deviation (SE%) of test detection system (Y) and control detection system (X) at different medical decision levels were calculated. The clinical acceptability and comparability between different detection systems were tested according to the standard of allowed total error of American Clinical Proficiency Testing Laboratory Improvement Amendments (CLIA'88).

Results

The test results of the sixteen parameters between the two different biological detection systems were well-correlated (r² ≥0.95, p < 0.01). Linearity study showed acceptable linearity ranges for all the parameters. The relative deviation SE% of sixteen biochemical parameters at different medical decisions levels, excepting relative deviation of TP at two levels and TBIL at one level was greater than 1/2 CLIA 88 allowable total error, while the relative deviation or absolute deviation of the rest of the test parameters at their medical decision levels was less than 1/2CLIA88 predetermined allowable total error, and the total pass rate was 93%, so the China-made equipment Mindray BS-2000M biochemical analyzer may be clinically acceptable.

Conclusion

Mindray BS-2000M has achieved the desirable photometry technical and analytical performance, and can therefore be used in modern clinical laboratories.

Objective

To study LpxA/C/D and pmrA/B gene systems role in colistin resistant clinical strains of Acinetobacter baumannii.

Methods

Transmission Electron Microscopy (TEM) was employed to observe changes in the cell wall, inner and outer membranes. GC-Chromatography was applied to quantify the fatty acid content as a result of changes in the LPS in clinical A. baumannii strains. Furthermore, the isolates were subjected to molecular biology approaches employing Real-Time PCR to evaluate the mRNA expression levels of pmrA and pmrB. Colistin-resistant and colistin-dependent A. baumannii isolates were further screened by PCR amplification to determine mutations in lpxA, lpxC and lpxD genes responsible for lipid A biosynthesis.

Results

Transmission Electron microscopy of six A. baumannii isolates showed that 2 colistin-resistant (Col-R) and 2 colistin-dependent (Col-D) A. baumannii had decreased integrity of the outer and inner membrane and lost uniformity in the periplasmic space compared with 2 susceptible (Col-S) Acinetobacter baumannii strains. GC-Chromatography indicated that there was a trend of decreased saturated and unsaturated fatty acid biosynthesis, especially long carbon chain (16:0, 17:0 and 18:0 carbon chains) and almost no alcohol substitution on the low carbon chain fatty acid (increased modification on the long chain fatty acid and the loss of most unidentified fatty acid peaks) in Col-D and Col-R strains in comparison with Col-S and ATCC19606 strains. The expression data from RT-PCR of PmrA/B two-component regulatory system suggest that upregulated gene expression in 4 Col-R and 3 Col-D strains may lead to a modification in and/or loss of lipid A. Lipid A biosynthesis genes sequencing results revealed deletion of 11 bp nucleotides and change of one nucleotide in lpxA, and a nucleotide point mutation and insertion in lpxC and lpxD of Col-D and Col-R strains resulting in defective lipid A production and outer membrane lipid synthesis.

Conclusion

Mechanisms of colistin resistance in clinical strains of A. baumannii show that colistin may not serve as an antibiotic of the last resort for treating MDR A. baumannii infections when other antibiotics are ineffective. The mechanisms of colistin resistance should provide an impetus for future research on the development of newer alternative therapies to treat emerging MDR A. baumannii.

Objective

This work was to investigate the drug resistance, molecular and virulence characteristics of methicillin-resistant Staphylococcus aureus (MRSA) in burn patients and provide empiric antibiotic therapy for clinical treatment.

Methods

A total of 365 non duplicate Staphylococcus strains, including 85 MRSA and 280 methicillin-susceptible Staphylococcus aureus (MSSA), were collected from burn patients from 2008 to 2015. The susceptibility tests of antibacterial agents were performed by the Kirby-Bauer disk diffusion method. Polymerase chain reaction (PCR) and gel electrophoresis amplification technology were used to identify the mecA, qacA/B, and virulence genes, such as staphylococcal enterotoxin A (sea), staphylococcal enterotoxin B (seb), panton-valentine leukocidin (PVL), hemolysin A (hla), fibronectin-binding protein A (fnbA) of MRSA. Pulsed field gel electrophoresis (PFGE) was performed to analysis nucleotide homology of MRSA isolates.

Results

The resistance rates of MRSA to commonly-used antimicrobial agents were significantly higher than that of MSSA. The PCR assay results showed that all MRSA were mecA-positive and qacA/B-positive strains. The prevalence of virulence gene sea, seb, PVL, hla and fnbA were 70%, 60%, 90%, 85%, 5% in MRSA strains, respectively. Also, the prevalence of virulence genes sea, seb, pvl, hla and fnbA were 40%, 33.3%, 93.3%, 100%, and 20% in MSSA strains, respectively. According to the PFGE analysis, sixteen of MRSA isolates were classified into A, B, and C types and corresponding amounts were 13 (81.25%), 2 (12.5%), and 1 (6.25%), respectively.

Conclusions

The burn patients who infected MRSA have a higher drug resistance, and further recognition the molecular characteristics of MRSA is necessary to find better treatment options.

Mitochondria, vital organelles, produce ATP efficiently for energy homeostasis via aerobic respiration and play a key role in tricarboxylic acid cycle, fatty acid oxidation, regulating of calcium homeostasis. Mitochondria are principal regulators of cell signaling via production of reactive oxygen species. Under various exogenous and/or endogenous stresses, mitochondria have the ability to adapt to changing environmental conditions, termed mitochondrial stress. Mitochondrial stress reconstructs mitochondrial homeostasis through integrated signaling termed the mitochondrial unfolded protein response (UPR_mt). The mitochondrial UPR_mt is a response of the cell to relieve mitochondrial damage and respond to proteotoxic stress specifically in mitochondria. Meanwhile, the mitochondrial UPR_mt can sustain proteostasis and maintain overall cellular homeostasis. This review highlights the complex molecular mechanisms of the mitochondrial UPR_mt.

Fat embolism is a known complication of bone marrow infarction in patients with sickle cell disease (hemoglobin SS and hemoglobin SC disease). We report a case of a 36-year-old woman with hemoglobin SC disease who presented with headache, nausea, and photophobia. The patient experienced hypoxic respiratory failure, anemia and thrombocytopenia and expired four days later. Postmortem examination revealed fat emboli in the lungs and brain. Although uncommon, fat embolism syndrome should be considered in the differential diagnosis of acute complications with hemoglobin SC disease.

Background

The Bruker Biotyper MALDI-TOF MS (Biotyper) system was evaluated for identification of anaerobic bacteria by chemical extraction and the direct smear technique.

Method

A total of 216 strains of anaerobic bacteria representing 36 species were analyzed by two methods. 16S rDNA sequence analysis was used to resolve discrepancies.

Results

The results showed that 202/216 (93.5%) strains were correctly identified following chemical extraction, among them, 176 strains (81.5%) were secured to both genus and species (score > 2.00); another 26 strains (12%) were secured to genus only (score between 1.70 and 2.00). Following direct smear, 194/216 (89.8%) anaerobic bacteria were identified, 155 strains (71.7%) were secured to both genus and species (score) > 2.0 whereas 39 (18%) strains were identified to genus only (score between 1.70 and 2.00). Fourteen strains were not identified (score < 1.70) by MALDI-TOF MS following chemical extraction whereas 22 strains were not identified with the direct smear technique. Although direct smear had a less isolate number for score values >2.00, However the overall identification differences were not statistically significant (0.05 < P < 0.1).

Conclusion

MALDI-TOF MS identification following the direct smear technique appears to be non-inferior to standard chemical extraction. It may be an acceptable alternative to chemical extraction methods for routine identification of anaerobic bacteria in a medical microbiology laboratory.

Background

Respiratory tract infection (RTI) is a common disease among children of all ages that causes high hospitalization and mortality rates. Infection with more than one pathogen has been reported in RTI; however, the association of the pathogen spectrum in upper and lower respiratory tract infections remains unclear.

Methods

A prospective study was conducted during February to October 2016. Fifty-five nasopharyngeal swabs (NPS) and 30 bronchoalveolar lavage fluid (BALF) samples from 55 hospitalized children aged less than 14 years (mean age 40 months) and diagnosed with an RTI were collected. All samples were detected for 18 respiratory pathogens using the Filmarray assay, real-time PCR, or nested PCR methods. Detection results and clinical characteristics of all cases were analyzed using chi-square and t tests.

Results

Forty-one of 55 (74.5%) NPS obtained from children were positive for at least one pathogen by the Filmarray assay. Of these cases, 53.7% (22/41) were co-infected. The most commonly detected pathogen was rhinovirus (RV), followed by Mycoplasma pneumoniae (MP) and respiratory syncytial virus (RSV). Infection by both RV and MP was the most frequently observed pattern of co-infection. Similar results were observed using real-time PCR. The pathogens in the NPS from 76.6% of cases detected by Filmarray and 80.0% of cases by real-time PCR included all the pathogens detected in the BALF sample from the same individual. The Filmarray assay showed an 80% concordance rate with real-time PCR and had a turnaround time of less than 1.2 h. No significant differences were observed between the association of single-infection and co-infection with clinical characteristics, neither by Filmarray nor real-time PCR.

Conclusion

The spectrum of pathogens is mostly concordant in the upper and lower respiratory tract. Collecting NPS for detection can be a non-invasive and more convenient option compared with BALF. Although co-infection is common in children with an RTI, the clinical significance of co-infection remains unclear and warrants further analysis.