Mapping the Reactions in a Single Zero-Valent Iron Nanoparticle

Nanoscale zerovalent iron (nZVI) possesses unique functionalities for metal-metalloid removal and sequestration. So far, direct evidence on the heavy metal-nZVI reactions in the solid phase is still limited due to low concentration of heavy metals and small size of nanoparticles. In this work, angstrom-resolution spectral mappings on the reactions of nZVI with chromate, arsenate, nickel, silver, cesium, and zinc ions are presented. This work was achieved with spherical aberration-corrected scanning transmission electron microscopy integrated with high-sensitivity X-ray energy-dispersive spectroscopy-scanning transmission electron microscopy (XEDS-STEM). Results confirm that iron nanoparticles have a core-shell structure. In addition, the removal mechanism significantly depends on the standard potential E⁰ (E⁰ is standard potential w.r.t. standard hydrogen electrode at 25 °C when free ion activity is 1.). For strong oxidizing agents, such as Cr(VI), the removal mechanism is diffusion and encapsulation in the core area of the nZVI particle. For moderate oxidizers, such as As(V) with E⁰ more positive than that of iron, the removal mechanism is adsorption at the surface, followed by diffusion and encapsulation into the particle between the core and the shell. For metal cations with an E⁰ close to or more negative than that of iron, such as Cs(I) and Zn(II), the removal mechanism is sorption or surface-complex formation. For metal cations with E⁰ much more positive than that of iron, such as Ag(I), the removal mechanism is rapid reduction on the surface of nZVI. Meanwhile, metals with E⁰ slightly more positive than that of iron, such as Ni(II), can be immobilized at the nanoparticle surface via sorption and reduction. The synergetic effects of sorption, reduction, and encapsulation mechanisms of nZVI lead to rapid reactions and high efficiency for treatment and immobilization of many toxic heavy metals. Results also demonstrate that the XEDS-STEM technique is a powerful tool for studying reactions in individual nanoparticles and is particularly valuable for mapping trace-level elements in environmental media.

[Analysis of the clinical and electrophysiological characteristics of multifocal motor neuropathy]

Ten patients diagnosed with multifocal motor neuropathy (MMN) were recruited in the Department of Neurology at Chinese PLA General Hospital from January 1, 2009 to August 31, 2015. The clinical and electrophysiological features were analyzed retrospectively. All patients complained of progressive asymmetric limb weakness, which was more severe in distal than in proximal. Five presented muscle atrophy. None had sensory disturbances. All suffered diminished or disappeared tendon reflex, whereas Babinski signs were negative. Multi-focal conduction block (CB) was confirmed by nerve conduction studies (NCS) in all patients and 7 showed spontaneous potentials in needle electrode electromyography. Abnormal sensory nerve conduction was seen in 3 patients. Laboratory test revealed anti-ganglioside GM1 antibody in cerebrospinal fluid (CSF) in 6 cases and elevated CSF protein in 7 cases. Limb weakness alleviated greatly in 9 cases after intravenous immunoglobulin (IVIg) treatment. But the other one reported poor response, who had long course of disease, serious limb weakness and obvious muscle atrophy. Motor nerve damage is the most important manifestation of MMN and sensory nerve damage may also appear. NCS is essential to the diagnosis of this disease, with CB as the characteristic electrophysiological feature. IVIg is an effective treatment.

[Characteristics of repetitive nerve stimulation in 53 cases of amyotrophic lateral sclerosis]

Objective: To investigate the feature of repetitive nerve stimulation (RNS) in patients with amyotrophic lateral sclerosis (ALS) and correlation between RNS and clinical features and electromyography (EMG) findings of the corresponding muscle. Methods: Needle EMG and RNS were performed in 53 patients with ALS, who were recruited into Department of Neurology of Chinese PLA general hospital during April to December in 2016. Decrement of the compond muscle action potential (CMAP) in response to RNS of different nerves and stimulus frequencies was compared. The effects of gender, age of onset, disease duration, region of onset, ALS functional rating scale-revised (ALSFRS-R) and rate of disease progression (ΔFS) on the decrement were analyzed. Results: 49.1% of patients with ALS had decremental responses to low frequency RNS (LF-RNS) in accessory nerve, which was lower in ulnar nerve (4.3%) and common peroneal nerve (2.6%). Decremental responses of accessory nerve at 3 Hz were observed in 49.1% of patients with ALS, more frequent than 30.2% at 1 Hz. None of the patients had increased responses to high frequency RNS. Patients with upper-limb-onset, longer disease duration and lower ALSFRS-R tended to have more frequent decrement of CMAP in response to RNS. The decrement with LF-RNS of accessory nerve was in concert with neurogenic damage of sternocleidomastoid muscle with needle EMG (r=0.365, P=0.007). There were 3 patients who had decremental responses to LF-RNS in accessory nerve without clinical involvement and neurogenic damage of sternocleidomastoid muscle. Conclusions: There is significant decrement of CMAP in response to LF-RNS of accessory nerve in patients with ALS, which may reveal neuromuscular junction (NMJ) impairment. It may indicated a dying-back pattern of disease progression which derived from motor neuron terminal or NMJ to neuronal soma that some patients with ALS have decremental responses in RNS without clinical involvement and neurogenic damage of sternocleidomastoid muscle.

A double-edged sword: Should stage IV non-small cell lung cancer patients be informed of their cancer diagnosis?

This study aimed to examine whether awareness of cancer diagnosis and prognosis among patients with stage IV lung cancer treated with first-line erlotinib vary with psychological distress and quality of life (QoL). This study was carried out at the Comprehensive treatment Department of Tianjin Cancer Hospital between August 2013 and September 2015 among patients ≥18 years-old and suffering from EGFR mutation-positive stage IV non-small cell lung cancer (NSCLC) treated with first-line erlotinib (150 mg/day; N = 137). The Hospital Anxiety and Depression Scale (HADS) was administered before (baseline) and after 12 weeks of treatment. QoL was assessed using the Functional Assessment of Cancer Therapy-Lung (FACT-L) questionnaire. Diagnosis and prognosis awareness was assessed by interview. Among patients, 21% reported to be fully aware of their disease; 41% were only aware of the diagnosis, not the stage; and 51% were not aware at all. Among patients, 63.5% reported elevated anxiety, 71.5% were depressed, and 75.2% had HADS score ≥15 (emotional distress). Patients who were totally and partly aware experienced improvements in HADS and FACT-L compared with baseline (all p < .05). Patients who were not aware scored better than the other patients for all FACT-L subscales from baseline to 12 weeks (all p < .05). Aware patients experienced improvements from baseline in HADS and FACT-L (all p < .05). Awareness of cancer diagnosis and stage was associated with initially high global distress and poorer QoL. Unaware patients exhibited better emotional distress and QoL during first-line therapy with erlotinib for EGFR mutation-positive advanced NSCLC.

Visualizing Arsenate Reactions and Encapsulation in a Single Zero-Valent Iron Nanoparticle

A nanostructure-based mechanism is presented on the enrichment, separation, and immobilization of arsenic with nanoscale zero-valent iron (nZVI). The As-Fe reactions are studied with spherical aberration corrected scanning transmission electron microscopy (Cs-STEM). Near-atomic resolution (<1 nm³) electron tomography discovers a thin continuous layer (23 ± 3 Å) of elemental arsenic sandwiched between the iron oxide shell and the zerovalent iron core. This points to a unique mechanism of nanoencapsulation and proves that the outer layer, especially the Fe(0)-oxide interface, is the edge of the As-Fe reactions. Atomic-resolution imaging on the grain boundary provides strong evidence that arsenic atoms diffuse preferably along the nonequilibrium, high-energy, and defective polycrystalline grain boundary of iron oxides. Results also offer direct evidence on the surface sorption or surface complex formation of arsenate on ferric hydroxide (FeOOH). The core-shell structure and unique properties of nZVI clearly underline rapid separation, large capacity, and stability for the treatment of toxic heavy metals such as cadmium, chromium, arsenic, and uranium.

[Clinical and electrophysiological studies of oxaliplatin-induced peripheral neuropathy]

OBJECTIVE

To identify the sensitive scales and the early change of nerve conduction for chronic oxaliplatin-induced peripheral neuropathy (OXLIPN), and to investigate correlation between the symptoms of acute OXLIPN and chronic OXLIPN.

METHODS

Between December 2014 and August 2015, 16 colorectal cancer patients confirmed by pathology, from department of Oncology, Chinese PLA General Hospital, scheduled to receive XELOX, completed the acute neurotoxic symptoms questionnaire at the end of 1 cycles and the scales of TNSc and NCI-CTC at the baseline and the end of 4 cycles. Nerve conduction studies (bilateral peroneal nerves and sural nerves) were performed in 11 patients at the baseline and the end of 4 cycles.

RESULTS

After chemotherapy, TNSc increased 1-9 points for all cases, while NCI-CTC increased 1 point for only 9 cases, the remaining 7 cases had the same NCI-CTC score before and after chemotherapy, where TNSc increased 1-6 points. Left sural nerve a-SNAP (amplitude of sensory nerve action potential) was (15.3±5.8)μV before chemotherapy and(12.3±5.0)μV after chemotherapy. Right sural nerve a-SNAP was (17.4±8.6)μV before chemotherapy and (13.3±6.7)μV after chemotherapy. After chemotherapy, these datum were significantly reduced for left peroneal nerve distal and proximal a-CMAP (amplitude of compound muscle action potential), bilateral sural nerve a-SNAP and left sural nerve SCV (sensory conduction velocity) (P<0.05). After chemotherapy, TNSc was correlated significantly with the acute neurotoxic symptoms questionnaire (Spearman r=0.698, P=0.003).

CONCLUSIONS

TNSc is more sensitive to the severity and changes in chronic OXLIPN than NCI-CTC. Sural nerve a-SNAP has a higher sensitivity for the early changes of nerve conduction studies in chronic OXLIPN. Patients who have more symptoms of acute OXLIPN are those who eventually develop more severe chronic OXLIPN.

Solution and surface chemistry of the Se(IV)-Fe(0) reactions: Effect of initial solution pH

Aspects of solution and solid-phase reactions between selenite (Se(IV)) and nanoscale zero-valent iron (nZVI) were investigated. Experimental results on the effects of initial solution pH, formation and evolution of nZVI corrosion products, and speciation of selenium in nZVI were presented. In general, the rate of Se(IV) removal decreases with increasing initial pH. The observed rate constants of Se(IV) removal decreased from 0.3530 to 0.0364 min^-1 as pH increased from 4.0 to 10.0. Composition and morphology of nZVI corrosion products and selenium species were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Results confirmed that Se(IV) was reduced to Se(0) and Se(-II) by nZVI. Lower solution pH favored further reduction of Se(0) to Se(-II). Amorphous FeOOH, magnetite/maghemite (Fe₃O₄/γ-Fe₂O₃) and ferrous hydroxide (Fe(OH)₂) were identified as the main corrosion products. Under alkaline conditions, the corrosion products were mainly of Fe(OH)₂ along with small amounts of Fe₃O₄, while nZVI in acidic solutions was oxidized to mostly Fe₃O₄ and amorphous FeOOH. Furthermore, these corrosion products acted as intermediates for electron transfer and reactive/sorptive sites for Se(IV) adsorption and reduction, thus played a crucial role in the removal of aqueous Se(IV).

[Impact of different degree pulpitis on cell proliferation and osteoblastic differentiation of dental pulp stem cell in Beagle immature premolars]

OBJECTIVE

To compare the proliferation and osteoblastic differentiation of dental pulp stem cell (DPSC) isolated from normal and inflamed pulps of different degrees in Beagle immature premolars, and provide evidence for the use of inflammatory DPSC (IDPSC).

METHODS

This study evaluated 14 Beagle's young premolars (21 roots). In the experiment group, irreversible pulpitis was induced by pulp exposure and the inflamed pulps were extracted 2 weeks and 6 weeks after the pulp chamber opening.For the control group, normal pulps were extracted immediately after the exposure. HE staining and real-time PCR were performed to confirm the inflammation. The cells were isolated from the inflamed and normal pulps (IDPSC and DPSC). Cell proliferation and osteoblastic differentiation potentials of the two cells were compared.

RESULTS

Inflammation cells infiltration was observed in the inflamed pulps by HE staining. The expression of inflammatory factor was much higher in the 6 week inflamed pulp. IDPSC had higher potential of cell proliferation and osteoblastic differentiation potentials. Furthermore, the osteoblastic differentiation potentials of IDPSC from 2 week inflamed pulp were higher than those from 6 week inflamed pulp.

CONCLUSION

The potential of cell proliferation and osteoblastic differentiation of DPSC was enhanced at early stage of irreversible pulpitis, and reduced at late stage in Beagle immature premolars.

[An analysis of characteristics of nerve conduction in 154 cases of amyotrophic lateral sclerosis]

Objective: To analyze the features of nerve conduction in patients with amyotrophic lateral sclerosis (ALS), and explore the correlation between compound muscle action potential (CMAP) amplitude and disease duration and revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R). Methods: Standard motor and sensory nerve conduction studies were performed in 154 patients with ALS. The following parameters were collected including CMAP amplitude, distal motor latency (DML), motor conduction velocity, sensory conduction velocity and sensory nerve action potential amplitude. Regression study was done to explore the correlation between CMAP amplitude and disease duration and ALSFRS-R. Results: Motor nerve conduction abnormalities were presented in a majority of the patients with prolonged DML in the tibial nerve, median nerve and ulnar nerve as the most common form (61.06%-81.42%), followed by decreased CMAP amplitude (30.12%-53.98%), decreased MCV (12.05%-16.81%) and absence of CMAP (2.65%-9.73%). Sensory nerve conduction abnormalities were detected in a small proportion of patients and the decreased SCV, decreased SNAP amplitude and absence of SNAP in the sural nerve, median nerve and ulnar nerve were found in 1.22%-2.73%, 0-1.82% and 0-1.22% patients respectively. No correlation was found between CMAP of the common peroneal nerve, tibial nerve, median nerve and ulnar nerve and the disease duration (P>0.05), while significant positive correlation was established between CMAP amplitude of the median nerve and ulnar nerve and ALSFRS-R (r=0.273, P=0.016; r=0.357, P=0.001). Conclusions: Motor nerve conduction is abnormal in a majority of ALS patients with prolonged DML as the most common form, while abnormal sensory nerve conduction is only found in a few of ALS patients. CMAP amplitude of the median nerve and ulnar nerve might be of certain clinical value in evaluating the severity of ALS.

[Needle electromyography features and values of paraspinal muscle parameters in assessment of respiratory function of patients with amyotrophic lateral sclerosis]

Objective: To analyze the features of needle electromyography (EMG) in patients with amyotrophic lateral sclerosis (ALS), and explore the correlation between EMG parameters of the tenth thoracic paraspinal muscle and disease duration, rate of disease progression, forced vital capacity (FVC) and revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R). Methods: Standard EMG was recorded from unilateral sternocleidomastoid muscle and/or tongue muscles, upper and lower limbs muscles and the tenth thoracic paraspinal muscle in 112 patients with definite ALS between March 2012 and June 2013 in the Department of Neurology at Chinese PLA General Hospital. Parameters studies included spontaneous potentials, duration and amplitude of motor unit potentials (MUP), pattern of recruitment. Results: EMG revealed diffuse neurogenic changes in each case. Fibrillation potential or positive sharp waves were found in some muscles in all of patients, and both of them were found in most of the cases. Fasciculation potentials (FPs) were found in 8 patients and accompanied with fibrillation potential and positive sharp waves in 5 of them. Complex repetitive discharges (CRDs) were found in only 1 patient. Duration and amplitude of MUP was prolonged and increased in ALS patients, and the rate of high amplitude and decreased recruitment pattern were 35.71% and 72.32%, respectively. Logistic regression analysis revealed an association of the FVC loss with the drop of ALSFRS-R and peak amplitude of the tenth thoracic paraspinal muscle. Conclusions: The abnormal spontaneous activity with high frequency are fibrillation potentials and/or positive sharp waves. However, FPs is observed in a small number of patients and CRDs is rarely seen in ALS. The ALSFRS-R and peak amplitude of thetenth thoracic paraspinal muscle may be of certain clinical value in estimating the severity of disease especially the respiratory dysfunction in ALS patients.

miR-143 suppresses the proliferation of NSCLC cells by inhibiting the epidermal growth factor receptor

MicroRNAs (miRs) regulate the proliferation and metastasis of numerous cancer cell types. It was previously reported that miR-143 levels were downregulated in non-small cell lung cancer (NSCLC) tissues and cell lines, and that the migration and invasion of NSCLC cells was inhibited upon suppression of cell proliferation and colony formation by the upregulation of miR-143. Epidermal growth factor receptor (EGFR), which is a vital factor in the promotion of cancer cell proliferation and has been investigated as a potential focus in cancer therapy, has been reported to be a possible target of miR-143. The present study aimed to investigate the role of miR-143 in NSCLC using NSCLC cell lines and primary cells from NSCLC patients. NSCLC cells were co-transfected with EGFR and miR-143, and the mRNA and protein expression of EGFR were analyzed. Furthermore, the activity of the transfected cancer cells with regard to colony formation, migration, invasion and apoptosis were evaluated. The levels of miR-143 were decreased in the NSCLC cell lines and primary cells from patients with NSCLC compared with the controls. Following transfection with miR-143, the ability of NSCLC cells to proliferate, form colonies, migrate and invade was inhibited. Similarly, knockdown of EGFR led to the suppression of NSCLC cell proliferation. The mRNA and protein expression levels of EGFR were significantly reduced following miR-143 overexpression, and the level of miR-143 was inversely correlated with that of EGFR in NSCLC cells. The results of the present study demonstrated that miR-143 was able to suppress NSCLC cell proliferation and invasion by inhibiting the effects of EGFR, suggesting that EGFR may be considered a potential target for NSCLC therapy.