Comparative in vitro cytotoxicity study on uncoated magnetic nanoparticles: effects on cell viability, cell morphology, and cellular uptake

Magnetic iron oxide nanoparticles (MIONPs) must be biocompatible, and a thorough knowledge on their potential cytotoxicity is crucial for their biomedical applications. However, the detailed study about the effects of iron oxide nanoparticles on cell viability, cell morphology, and cellular uptake of different mammalian cells is still insufficient. In this paper, comparative cytotoxicity study of uncoated magnetite nanoparticles at different concentrations was performed on human cervical cancer cell line (HeLa) and immortalized normal human retinal pigment epithelial cell line (RPE). The size, structure, and magnetic behavior of the MIONPs were characterized using transmission electron microscopy (TEM), X-ray diffractometry (XRD), and vibrating sample magnetometry (VSM) respectively. After 24-hour incubation with the MIONPs, the cell viability was determined by live/dead assay, the cell morphology at high magnification was observed under scanning electron microscopy (SEM), and the cellular uptake of MIONPs was measured under TEM and verified by energy-dispersive X-ray spectroscopy (EDX) analysis. Our results indicate that the uncoated MIONPs at a high concentration (0.40 mg/ml) were toxic to both HeLa and RPE cells. However, the cytotoxicity of uncoated MIONPs at low concentrations was cell-type specific, and RPE cells were more susceptible to these MIONPs than HeLa cells. The effects of the MIONPs on cell morphology and the nanoparticles uptake also showed different features between these two cell lines. Hence cell type should be taken into consideration in the in vitro cytotoxicity study of uncoated MIONPs. Additionally, it should be noticed that the cell morphological changes and the uptake of nanoparticles can take place even though no toxic effect of these MIONPs at low concentrations was reflected in the traditional cell viability assay.

Long-term Clinical Outcomes in Patients Undergoing Lumbar Discectomy by Fenestration

Objective:

To investigate the long-term outcome of discectomy and relevant factors associated with clinical outcome.

Methods:

Patients who underwent lumbar discectomy by fenestration were evaluated retrospectively, using the Oswestry disability index (ODI; 0 - 20 minimal, 21 - 40 moderate, > 41 severe disability) and the Stauffer-Coventry criteria (‘excellent’, ‘good’, ‘fair’, ‘poor’) to measure clinical and radiographic outcomes.

Results:

Sixty patients (mean follow-up, 214 months) were included in the analysis. At final follow-up, patients were rated as ‘excellent’ (n = 31), ‘good’ (n = 13), ‘fair’ (n = 5) and ‘poor’ (n = 11) using the Stauffer-Coventry criteria; the latter group included six patients who underwent reoperations. The mean ODI score was 11.2. The height of the operative intervertebral space was significantly inversely correlated with the follow-up ODI value. Heavy manual work, smoking and a long duration of aggressive preoperative symptoms were significantly associated with unsatisfactory outcomes.

Conclusions:

The long-term outcome of lumbar discectomy by fenestration was satisfactory in the majority of patients. Heavy manual work, smoking and the duration of aggressive preoperative symptoms were negative predictors of a good clinical outcome.

Analysis of the causes and types of traumatic spinal cord injury based on 561 cases in China from 2001 to 2010

OBJECTIVES

A remarkable increase in traumatic spinal cord injury (TSCI) morbidity has occurred in China from 2001 to 2010 due to rapid industrial and economic development; this increase seriously threatens public health. The current study investigated the major causes and severity of TSCI in 561 hospitalized TSCI patients who came from all over China to the General Hospital of Chinese People's Armed Police Forces.

METHODS

Information (including each patient's age, gender, time and cause of injury and severity of spinal cord injury (SCI, complete or incomplete)) regarding 561 hospitalized TSCI patients whose injuries occurred between 2001 and 2010 was retrospectively analyzed.

RESULTS

Among the 561 patients, the youngest was 9 months old and the oldest was 67 years old; the average patient age was 34.74 ± 12.24 years. The sex ratio was 4.1:1 (male:female). The injuries were primarily caused by transportation accidents (51.2%), falling from a height (23.9%), tamping (8.6%), stumbling (8.0%), stabbing (3.0%) and crushing (1.8%). Although no statistically significant associations were observed between the different injury causes and severity of the injury, a statistically significant association was observed between the different injury causes and levels of the lesion.

CONCLUSION

Transportation accidents, falling from a height, tamping, stumbling, stabbing and crushing are the most common causes of TSCI. No statistically significant relationships were observed between certain injury causes and either complete or incomplete injury. However, different injury causes usually led to different levels of the lesion. No statistical differences were observed between the levels of the lesion and either complete or incomplete injury.

Generation of polarization-entangled photon pairs via concurrent spontaneous parametric downconversions in a single χ(2) nonlinear photonic crystal

We propose a scheme for generating polarization-entangled photon pairs using a χ((2)) nonlinear photonic crystal, which is designed for enabling two concurrent quasi-phase-matched spontaneous parametric downconversion processes. Beamlike photon pairs produced from each process are collinear but noncollinear with the pump. Moreover, the source we design works in a postselection-free way and applies to both degenerate and nondegenerate cases. Combining possible waveguide technologies, our scheme may provide an integrated polarization entanglement source.

Frailty in relation to the risk of falls, fractures, and mortality in older Chinese adults: results from the Beijing Longitudinal Study of Aging

OBJECTIVES

Falls are well known to be associated with adverse health outcomes, especially when complicated by fracture. Falls are more common in people who are frail and readily related to several items in the frailty phenotype. Less is known about the relationship between falls and frailty defined as deficit accumulation. Our objective was to investigate the relationship between falls, fractures, and frailty based on deficit accumulation.

DESIGN

Representative cohort study, with 8 year follow-up.

SETTING

The Beijing Longitudinal Study of Aging (BLSA).

PARTICIPANTS

3,257 Chinese people aged 55+ years at baseline.

MEASUREMENTS

A frailty index (FI) was constructed using 33 health deficits, but excluding falls and fractures. The rates of falls, fractures and death as a function of age and the FI were analyzed. Multivariable models evaluated the relationships between frailty and the risk of recurrent falls, fractures, and mortality adjusting for age, sex, and education. Self or informant reported fall and fracture data were verified against participants' health records.

RESULTS

Of 3,257 participants at baseline (1992), 360 people (11.1%) reported a history of falls, and 238 (7.3%) reported fractures. By eight years, 1,155 people had died (35.3%). The FI was associated with an increased risk of recurrent falls (OR=1.54; 95% confidence interval (CI)=1.34-1.76), fractures (OR=1.07; 95% CI=0.94-1.22), and death (OR=1.50, 95% CI=1.41-1.60). The FI showed a significant effect on mortality in a multivariate Cox regression model (Hazard Rate=1.29, 95% CI=1.25-1.33). When adjusted for the FI, neither falls nor fractures were associated with mortality.

CONCLUSION

Falls and fractures were common in older Chinese adults, and associated with frailty. Only frailty was independently associated with death.

Hemolytic properties of synthetic nano- and porous silica particles: the effect of surface properties and the protection by the plasma corona

Novel silica materials incorporating nanotechnology are promising materials for biomedical applications, but their novel properties may also bring unforeseen behavior in biological systems. Micro-size silica is well documented to induce hemolysis, but little is known about the hemolytic activities of nanostructured silica materials. In this study, the hemolytic properties of synthetic amorphous silica nanoparticles with primary sizes of 7-14 nm (hydrophilic vs. hydrophobic), 5-15 nm, 20 nm and 50 nm, and model meso/macroporous silica particles with pore diameters of 40 nm and 170 nm are investigated. A crystalline silica sample (0.5-10 μm) is included for benchmarking purposes. Special emphasis is given to investigations of how the temperature and solution complexity (solvent, plasma), as well as the physicochemical properties (such as size, surface charge, hydrophobicity and other surface properties), link to the hemolytic activities of these particles. Results suggests the potential importance of small size and large external surface area, as well as surface charge/structure, in the hemolysis of silica particles. Furthermore, a significant correlation is observed between the hemolytic profile of red blood cells and the cytotoxicity profile of human promyelocytic leukemia cells (HL-60) induced by nano- and porous silica particles, suggesting a potential universal mechanism of action. Importantly, the results generated suggest that the protective effect of plasma towards silica nanoparticle-induced hemolysis as well as cytotoxicity is primarily due to the protein/lipid layer shielding the silica particle surface. These results will assist the rational design of hemocompatible silica particles for biomedical applications.

The association of plasma free amino acids with liver enzymes in Type 2 diabetic patients

BACKGROUND

Elevated γ-glutamyl transpeptidase (GGT) and alanine aminotransferase (ALT) could predict the risk of Type 2 diabetes (T2D), but the reason for their elevation was unclear. GGT and ALT mediated the metabolism of many amino acids (AA). Up to now, it was not investigated whether abnormal AA concentration was associated with elevated liver enzymes.

AIM

This study was to investigate the status of AA in T2D and their relationship with liver enzymes.

SUBJECTS AND METHODS

A total of 132 T2D patients and 137 healthy controls were recruited. Plasma free AA were measured by high-performance liquid chromatography. The contribution of individual AA to liver enzymes was assessed by stepwise linear regression.

RESULTS

a) The levels of alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, methionine, glutamate, and lysine were higher while the level of glycine was lower in T2D than in controls (all p<0.01). b) Glutamate contributed to GGT in T2D, and its contribution was even greater than that of waist circumference. Leucine, lysine, and glutamate contributed to ALT.

CONCLUSION

There were significant differences in plasma AA profile between T2D and controls. Abnormal AA might contribute to elevated liver enzymes. The interaction between AA, liver enzymes, and the risk of T2D should be further investigated by prospective studies.

Identification of the forensically important beetles Nicrophorus japonicus, Ptomascopus plagiatus and Silpha carinata (Coleoptera: Silphidae) based on 16S rRNA gene in China

Sarcophagous beetles play an important role in estimating postmortem interval time (PMI) in the later stages decomposition of carcasses. However, the morphological similarity of beetles usually poses a challenge for forensic scientists within their routine work. As a supplementary to traditional morphological method, molecular genetics identification is simple and time-saving. A molecular identification method involving a 288-bp segment of the 16S ribosomal RNA (16S rRNA) gene from 15 beetles of Silphidae (Coleoptera), collected from 5 locations in 4 Chinese provinces, was evaluated. Phenogram analysis of the sequenced segments by the unweighted pairgroup method analysis (UPGMA) method showed that all specimens were properly assigned into four species with strong similarity, which indicated the possibility of separation congeneric species with the short 16S rRNA fragment. These results will be instrumental for implementation of the Chinese database of forensically relevant beetles.

Pharmacological profile of phosphatidylinositol 3-kinases and related phosphatidylinositols mediating endothelin(A) receptor-operated native TRPC channels in rabbit coronary artery myocytes

BACKGROUND AND PURPOSE

Endothelin(A) (ET(A) ) receptor-operated canonical transient receptor potential (TRPC) channels mediate Ca²⁺ influx pathways, which are important in coronary artery function. Biochemical pathways linking ET(A) receptor stimulation to TRPC channel opening are unknown. We investigated the involvement of phosphatidylinositol 3-kinases (PI3K) in ET(A) receptor activation of native heteromeric TRPC1/C5/C6 and TRPC3/C7 channels in rabbit coronary artery vascular smooth muscle cells (VSMCs).

EXPERIMENTAL APPROACH

A pharmacological profile of PI3K was created by studying the effect of pan-PI3K, pan-Class I PI3K and Class I PI3K isoform-selective inhibitors on ET(A) receptor-evoked single TRPC1/C5/C6 and TRPC3/C7 channel activities in cell-attached patches from rabbit freshly isolated coronary artery VSMCs. The action of phosphatidylinositol 3-phosphate- [PI(3)P], 4-phosphate- [PI(4)P] and 5-phosphate- [PI(5)P] containing molecules involved in PI3K-mediated reactions were studied in inside-out patches. Expression of PI3K family members in coronary artery tissue lysates were analysed using quantitative PCR.

KEY RESULTS

ET(A) receptor-operated TRPC1/C5/C6 and TRPC3/C7 channel activities were inhibited by wortmannin. However, ZSTK474 and AS252424 reduced ET(A) receptor-evoked TRPC1/C5/C6 channel activity but potentiated TRPC3/C7 channel activity. All the PI(3)P-, PI(4)P- and PI(5)P-containing molecules tested induced TRPC1/C5/C6 channel activation, whereas only PI(3)P stimulated TRPC3/C7 channels.

CONCLUSIONS AND IMPLICATIONS

ET(A) receptor-operated native TRPC1/C5/C6 and TRPC3/C7 channel activities are likely to be mediated by Class I PI3Kγ and Class II/III PI3K isoforms, respectively. ET(A) receptor-evoked and constitutively active PI3Kγ-mediated pathways inhibit TRPC3/C7 channel activation. PI3K-mediated pathways are novel regulators of native TRPC channels in VSMCs, and these signalling cascades are potential pharmacological targets for coronary artery disease.

Ketamine-induced ventricular structural, sympathetic and electrophysiological remodelling: pathological consequences and protective effects of metoprolol

BACKGROUND AND PURPOSE

Growing evidence suggests that long-term abuse of ketamine does harm the heart and increases the risk of sudden death. The present study was performed to explore the cardiotoxicity of ketamine and the protective effects of metoprolol.

EXPERIMENTAL APPROACH

Rats and rabbits were divided into control, ketamine, metoprolol alone and ketamine plus metoprolol groups. Ketamine (40 mg·kg(-1) ·day(-1), i.p.) and metoprolol (20 mg·kg(-1) ·day(-1), p.o.) were administered continuously for 12 weeks in rats and 8 weeks in rabbits. Cardiac function, electrophysiological disturbances, cardiac collagen, cardiomyocte apoptosis and the remodelling-related proteins were evaluated.

KEY RESULTS

Rabbits treated with ketamine showed decreased left ventricular ejection fraction, slowed ventricular conduction velocity and increased susceptibility to ventricular arrhythmia. Metoprolol prevented these pathophysiological alterations. In ketamine-treated rats, cardiac collagen volume fraction and apoptotic cell number were higher than those of control animals; these effects were prevented by co-administration of metoprolol. Consistently, the expressions of poly (ADP-ribose) polymerases-1, apoptosis-inducing factor and NF-κB-light-chain-enhancer of activated B cells were all increased after ketamine treatment and sharply reduced after metoprolol administration. Moreover, ketamine enhanced sympathetic sprouting, manifested as increased growth-associated protein 43 and tyrosine TH expression. These effects of ketamine were prevented by metoprolol.

CONCLUSIONS AND IMPLICATIONS

Chronic treatment with ketamine caused significant ventricular myocardial apoptosis, fibrosis and sympathetic sprouting, which altered the electrophysiological properties of the heart and increased its susceptibility to malignant arrhythmia that may lead to sudden cardiac death. Metoprolol prevented the cardiotoxicity of ketamine, indicating a promising new therapeutic strategy.

Comparison of efficacy between uncovered and covered self-expanding metallic stents in malignant large bowel obstruction: a systematic review and meta-analysis

AIM

Insertion of a self-expandable metallic stent (SEMS) can rapidly relieve colorectal obstruction. This study aimed to compare the efficacy between uncovered and covered SEMSs in the treatment of malignant colorectal obstruction.

METHOD

A systematic search in Medline, Embase, the Cochrane controlled trials register and bibliographies of retrieved articles was performed. Randomized controlled trials and other comparative studies comparing uncovered and covered SEMSs for treatment of malignant colorectal obstruction were selected for this systematic review and meta-analysis. The main outcome measures were technical success, clinical success, tumour ingrowth, tumour overgrowth, early migration (≤ 7 days), late migration (> 7 days), overall complications and the duration of stent patency.

RESULTS

Compared with covered SEMSs, uncovered SEMSs were associated with a lower late migration rate (relative risk 0.25; 95% CI 0.08, 0.80; P = 0.02), a higher tumour ingrowth rate (relative risk 5.99; 95% CI 2.23, 16.10; P = 0.0004) and a prolonged stent patency (weighted mean difference 15.34 days; 95% CI 4.31, 26.37; P = 0.006). There was no significant difference in technical success, clinical success, tumour overgrowth, early migration, perforation or overall complications between the two groups.

CONCLUSION

Tumour ingrowth occurred more frequently in the uncovered SEMS group, while late migration was more common in the covered SEMS group.

Patterns of co-morbidity with anxiety disorders in Chinese women with recurrent major depression

BACKGROUND

Studies conducted in Europe and the USA have shown that co-morbidity between major depressive disorder (MDD) and anxiety disorders is associated with various MDD-related features, including clinical symptoms, degree of familial aggregation and socio-economic status. However, few studies have investigated whether these patterns of association vary across different co-morbid anxiety disorders. Here, using a large cohort of Chinese women with recurrent MDD, we examine the prevalence and associated clinical features of co-morbid anxiety disorders.

METHOD

A total of 1970 female Chinese MDD patients with or without seven co-morbid anxiety disorders [including generalized anxiety disorder (GAD), panic disorder, and five phobia subtypes] were ascertained in the CONVERGE study. Generalized linear models were used to model association between co-morbid anxiety disorders and various MDD features.

RESULTS

The lifetime prevalence rate for any type of co-morbid anxiety disorder is 60.2%. Panic and social phobia significantly predict an increased family history of MDD. GAD and animal phobia predict an earlier onset of MDD and a higher number of MDD episodes, respectively. Panic and GAD predict a higher number of DSM-IV diagnostic criteria. GAD and blood-injury phobia are both significantly associated with suicidal attempt with opposite effects. All seven co-morbid anxiety disorders predict higher neuroticism.

CONCLUSIONS

Patterns of co-morbidity between MDD and anxiety are consistent with findings from the US and European studies; the seven co-morbid anxiety disorders are heterogeneous when tested for association with various MDD features.

Comparative study of different surgical transposition methods for ulnar nerve entrapment at the elbow

This study compared the therapeutic effects of two techniques for surgical decompression treatment for ulnar nerve entrapment at the elbow: subcutaneous transposition and modified submuscular transposition with Z-lengthening of the pronator teres origin. A total of 278 patients with ulnar nerve entrapment (McGowan grades I - III) were randomly assigned to undergo one of these techniques. All patients were followed-up for 2 years. The effects were assessed by preoperative and postoperative cross-sectional area, motor conduction velocity, sensory conduction velocity and nerve action potential. All of these parameters improved after surgery in both groups. For patients with grade I disease, there were no significant differences between the two techniques. For patients with grade II and III disease, modified submuscular transposition was associated with significantly greater improvements compared with subcutaneous transposition. In conclusion, subcutaneous ulnar nerve transposition is recommended for grade I patients and modified submuscular ulnar nerve transposition for grade II and III patients.

Procoagulant activity of erythrocytes and platelets through phosphatidylserine exposure and microparticles release in patients with nephrotic syndrome

Recent studies showed that an imbalance of prothrombotic and antithrombotic factors and impaired thrombolytic activity contribute to the thrombophilia of the nephrotic syndrome (NS). However, it is not clear whether blood cell injury and/or activation is involved in hypercoagulability in NS patients. Our objectives were to study the increase in microparticle (MP) release and phosphatidylserine (PS) exposure on the outer membrane of MP-origin cells in NS patients, and to evaluate their procoagulant activity (PCA). The subjects were patients with membranous nephropathy (MN), minimal change nephrotic syndrome (MCNS) and healthy controls. Analyses of MPs and PS exposure were performed using a flow cytometer. PCA was determined by clotting time and purified coagulation complex assays. We found that lactadherin+ MPs, which derived from red blood cells (RBC), platelet and endothelial cell, increased in NS patients. Moreover, PS exposure on RBCs and platelets in each NS group, especially in MN, are higher than that in controls. MP shedding and PS exposure of RBCs/platelets were highly procoagulant in NS patients. However, blockade of PS with lactadherin inhibited over 90% of PCA while an anti-tissue factor antibody had no significant inhibition effect. Our results demonstrate that the thrombophilic susceptibility of NS may be partly ascribed to MP release and PS exposure of RBCs, platelets and endothelial cells. Lactadherin is a sensitive probe for PS that has high anticoagulant activity.