Isothermal amplification based on specific signal extraction and output for fluorescence and colorimetric detection of nucleic acids.

Due to the complexity of compositions and low abundance of target in clinical sample, nucleic acids detection often suffers from false positives caused by nonspecific amplification. In in vitro diagnosis (IVD), PCR usually employ TaqMan probe to report specific signals and block false positive signals. However, nucleic acid isothermal amplifications, such as loop-mediated isothermal amplification (LAMP), lack of mature specific signal output mechanism, which prevents them from being used for IVD and point-of-care testing (POCT). In this work, we constructed a specific signal extract-to-output isothermal detection system (SSEI). SSEI contains a well-designed DNA probe for specific signal extraction and output in LAMP. This probe is a double-stranded DNA with an overhang sequence and named as extract-to-output probe (ETO probe). ETO probe can recognize the target-specific intermediate products in LAMP and release another signal-output probe (OP) to report the target-specific signals. With these unique properties, SSEI can detect as low as 10 copies of target DNA per reaction either by fluorescence detector or naked eyes. Moreover, due to the excellent performance against background nucleic acids interference, this biosensing platform had been successfully used for hepatitis B virus (HBV) clinical samples detection.

Dual functions of iridium(III) 2-phenylpyridine complexes: Metastasis inhibition and lysosomal damage.

Six N-phenylcarbazole/triphenylamine-appended half-sandwich iridium(III) 2-phenylpyridine complexes ([(η5-Cp*)Ir(C^N)Cl]) were prepared and characterized. Compared with cisplatin, these complexes exhibited potential antitumor activity against A549 and HeLa tumor cells, with IC50 values (half-maximum inhibitory concentration) that changed from 2.8 ± 0.8 µM to 39.5 ± 2.7 µM, and could block the migration of tumor cells. These complexes also effectively bound to protein (binding constant: ~104 M-1) and were transported through serum proteins, catalyzed the oxidation of coenzyme nicotinamide-adenine dinucleotide. Additionally, laser confocal microscopy and flow cytometry confirmed that these complexes possessed a non-energy-dependent cellular uptake mechanism, effectively accumulated in lysosomes (Pearson colocalization coefficient: ~0.74), damaged the integrity of acidic lysosomes, led to a change in the mitochondrial membrane potential, disrupted the cell cycle (G0/G1 phase), and eventually induced apoptosis. Above all, these complexes are potential antitumor agents with dual functions: metastasis inhibition and lysosomal damage.

The analysis of false prolongation of the activated partial thromboplastin time (activator: silica): Interference of C-reactive protein.

BACKGROUND: To investigate the effect of C-reactive protein on the activated partial thromboplastin time (APTT) (different activators) in different detecting systems. METHODS: The C-reactive protein and coagulation test of 112 patients with the infectious disease were determined by automation protein analyzer IMMAG 800 and automation coagulation analyzer STA-R Evolution, respectively. The pooled plasma APTT with different concentrations of C-reactive protein was measured by different detecting system: STA-R Evolution (activator: silica, kaolin), Sysmex CS-2000i (activator: ellagic acid), and ACL TOP 700 (activator: colloidal silica). In addition, the self-made platelet lysate (phospholipid) was added to correct the APTT prolonged by C-reactive protein (150 mg/L) on STA-R Evolution (activator: silica) system. RESULTS: The good correlation between C-reactive protein and APTT was found on the STA-R Evolution (activator: silica) system. The APTT on the STA-R Evolution (activator: silica) system was prolonged by 24.6 second, along with increasing C-reactive protein concentration. And the APTT of plasma containing 150 mg/L C-reactive protein was shortened by 3.4-6.9 second when the plasma was mixed with self-made platelet lysate. However, the APTT was prolonged unobviously on other detecting systems including STA-R Evolution (activator: kaolin), Sysmex CS-2000i, and ACL TOP 700. CONCLUSION: C-reactive protein interferes with the detection of APTT, especially in STA-R Evolution (activator: silica) system. The increasing in C-reactive protein results in a false prolongation of the APTT (activator: silica), and it is most likely that C-reactive protein interferes the coagulable factor binding of phospholipid.

[Correlations between serum interleukin-18 (IL-18) level, IL-18 gene promoter polymorphisms and the development of sepsis in children].

OBJECTIVE: To investigate the correlations of serum interleukin-18 (IL-18) level and IL-18 gene promoter polymorphisms to the development of sepsis in children. METHOD: Using enzyme-linked immunosorbent assay (ELISA), the authors tested the serum IL-18 level in 90 patients with sepsis and 123 normal controls, and their single nucleotide polymorphisms of the promoter region of IL-18 gene at position -607C/A and -137G/C were detected using polymerase chain reaction with sequence specific primers method and sequencing technique. RESULT: (1) The serum IL-18 level in sepsis groups was (196.56 +/- 157.32) pg/ml that was significantly higher than (66.16 +/- 41.63) pg/ml in normal controls (P < 0.01), the more severe the degree of sepsis was, the more significantly higher the serum IL-18 level was. The serum IL-18 level in non serious sepsis group was (152.87 +/- 114.96) pg/ml that was significantly higher than (66.16 +/- 41.63) pg/ml in normal controls, the serum IL-18 level in serious sepsis group was (191.98 +/- 169.72) pg/ml that was significantly higher than that in non serious sepsis group, and the serum IL-18 level in extremely serious sepsis patients was (323.89 +/- 159.35) pg/ml, the difference was highly significant (P = 0.000). The difference was significant among the groups with different severity of sepsis (P < 0.01). There was a negative correlation between PCIS (pediatric critical illness score) of sepsis and the serum IL-18 level (P < 0.01). (2) There were polymorphisms in IL-18 gene promoter of matched healthy children and sepsis in children. The GG genotype frequency (61.8%) of IL-18-137G/C in healthy children was the highest, followed by GC genotype (35.8%) and CC genotype (2.4%) in sequence. The G allele frequency (79.7%) was higher in IL-18-137G/C of healthy children than C allele (20.3%). The GG genotype frequency (71.1%) of IL-18-137G/C in septic children was the highest, the next were GC genotype (26.7%) and CC genotype (2.2%). The G allele frequency (84.4%) was higher in IL-18-137G/C of septic children than C allele (15.6%). The CA genotype frequency (61.0%) of IL-18-607C/A in healthy children was the highest, followed by CC genotype (26.8%) and AA genotype (12.2%). The C allele frequency (57.3%) was higher in IL-18-607C/A of healthy children than A allele (42.7%). The CA genotype frequency (76.7%) of IL-18-607C/A in septic children was the highest, followed by CC genotype (21.1%) and AA genotype (2.2%) in sequence. The C allele frequency (59.4%) was higher in IL-18-607C/A of septic children than A allele (40.6%). (3) The genotype frequency of IL-18-607 CA was 76.7% in sepsis groups that was significantly higher than 61.0% in normal controls, and the genotype frequency of -607 AA was 2.2% in sepsis groups that was significantly lower than 12.2% in normal controls, the difference was significant (P < 0.05). (4) In the order of -137CC, -137GC, -137GG, the serum IL-18 level in normal controls were as follows: (45.67 +/- 28.36) pg/ml, (53.27 +/- 37.91) pg/ml, (76.91 +/- 42.44) pg/ml, and with (140.50 +/- 60.10) pg/ml, (184.42 +/- 157.33) pg/ml, (237.02 +/- 161.76) pg/ml respectively in sepsis groups. In the order of -607AA, -607CA, -607CC, the serum IL-18 level in normal controls were: (48.80 +/- 32.11) pg/ml, (68.41 +/- 42.53) pg/ml, (70.17 +/- 43.87) pg/ml; and with (141.50 +/- 64.35) pg/ml, (151.21 +/- 121.19) pg/ml, (211.16 +/- 163.64) pg/ml respectively in sepsis groups. The difference was not significant among different groups (P > 0.05). CONCLUSION: The serum IL-18 level in sepsis groups was significantly higher than that in normal controls, which was related to the severity of sepsis. It was possible that the genotype of -607CA carriers was susceptible to sepsis, which mean that the genotype of -607CA might be susceptible genotype of sepsis. However, the genotype of -607AA might play an oppose role in the risk of sepsis.